python_code
stringlengths 0
1.8M
| repo_name
stringclasses 7
values | file_path
stringlengths 5
99
|
|---|---|---|
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <uapi/linux/fadvise.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "advise.h"
struct io_fadvise {
struct file *file;
u64 offset;
u32 len;
u32 advice;
};
struct io_madvise {
struct file *file;
u64 addr;
u32 len;
u32 advice;
};
int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);
if (sqe->buf_index || sqe->off || sqe->splice_fd_in)
return -EINVAL;
ma->addr = READ_ONCE(sqe->addr);
ma->len = READ_ONCE(sqe->len);
ma->advice = READ_ONCE(sqe->fadvise_advice);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
#else
return -EOPNOTSUPP;
#endif
}
int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
{
#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
io_req_set_res(req, ret, 0);
return IOU_OK;
#else
return -EOPNOTSUPP;
#endif
}
static bool io_fadvise_force_async(struct io_fadvise *fa)
{
switch (fa->advice) {
case POSIX_FADV_NORMAL:
case POSIX_FADV_RANDOM:
case POSIX_FADV_SEQUENTIAL:
return false;
default:
return true;
}
}
int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_fadvise *fa = io_kiocb_to_cmd(req, struct io_fadvise);
if (sqe->buf_index || sqe->addr || sqe->splice_fd_in)
return -EINVAL;
fa->offset = READ_ONCE(sqe->off);
fa->len = READ_ONCE(sqe->len);
fa->advice = READ_ONCE(sqe->fadvise_advice);
if (io_fadvise_force_async(fa))
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_fadvise(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_fadvise *fa = io_kiocb_to_cmd(req, struct io_fadvise);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK && io_fadvise_force_async(fa));
ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
| linux-master | io_uring/advise.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "sqpoll.h"
#include "fdinfo.h"
#include "cancel.h"
#include "rsrc.h"
#ifdef CONFIG_PROC_FS
static __cold int io_uring_show_cred(struct seq_file *m, unsigned int id,
const struct cred *cred)
{
struct user_namespace *uns = seq_user_ns(m);
struct group_info *gi;
kernel_cap_t cap;
int g;
seq_printf(m, "%5d\n", id);
seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid));
seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid));
seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid));
seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid));
seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid));
seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid));
seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid));
seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid));
seq_puts(m, "\n\tGroups:\t");
gi = cred->group_info;
for (g = 0; g < gi->ngroups; g++) {
seq_put_decimal_ull(m, g ? " " : "",
from_kgid_munged(uns, gi->gid[g]));
}
seq_puts(m, "\n\tCapEff:\t");
cap = cred->cap_effective;
seq_put_hex_ll(m, NULL, cap.val, 16);
seq_putc(m, '\n');
return 0;
}
/*
* Caller holds a reference to the file already, we don't need to do
* anything else to get an extra reference.
*/
__cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
{
struct io_ring_ctx *ctx = f->private_data;
struct io_sq_data *sq = NULL;
struct io_overflow_cqe *ocqe;
struct io_rings *r = ctx->rings;
unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1;
unsigned int sq_head = READ_ONCE(r->sq.head);
unsigned int sq_tail = READ_ONCE(r->sq.tail);
unsigned int cq_head = READ_ONCE(r->cq.head);
unsigned int cq_tail = READ_ONCE(r->cq.tail);
unsigned int cq_shift = 0;
unsigned int sq_shift = 0;
unsigned int sq_entries, cq_entries;
bool has_lock;
unsigned int i;
if (ctx->flags & IORING_SETUP_CQE32)
cq_shift = 1;
if (ctx->flags & IORING_SETUP_SQE128)
sq_shift = 1;
/*
* we may get imprecise sqe and cqe info if uring is actively running
* since we get cached_sq_head and cached_cq_tail without uring_lock
* and sq_tail and cq_head are changed by userspace. But it's ok since
* we usually use these info when it is stuck.
*/
seq_printf(m, "SqMask:\t0x%x\n", sq_mask);
seq_printf(m, "SqHead:\t%u\n", sq_head);
seq_printf(m, "SqTail:\t%u\n", sq_tail);
seq_printf(m, "CachedSqHead:\t%u\n", ctx->cached_sq_head);
seq_printf(m, "CqMask:\t0x%x\n", cq_mask);
seq_printf(m, "CqHead:\t%u\n", cq_head);
seq_printf(m, "CqTail:\t%u\n", cq_tail);
seq_printf(m, "CachedCqTail:\t%u\n", ctx->cached_cq_tail);
seq_printf(m, "SQEs:\t%u\n", sq_tail - sq_head);
sq_entries = min(sq_tail - sq_head, ctx->sq_entries);
for (i = 0; i < sq_entries; i++) {
unsigned int entry = i + sq_head;
struct io_uring_sqe *sqe;
unsigned int sq_idx;
if (ctx->flags & IORING_SETUP_NO_SQARRAY)
break;
sq_idx = READ_ONCE(ctx->sq_array[entry & sq_mask]);
if (sq_idx > sq_mask)
continue;
sqe = &ctx->sq_sqes[sq_idx << sq_shift];
seq_printf(m, "%5u: opcode:%s, fd:%d, flags:%x, off:%llu, "
"addr:0x%llx, rw_flags:0x%x, buf_index:%d "
"user_data:%llu",
sq_idx, io_uring_get_opcode(sqe->opcode), sqe->fd,
sqe->flags, (unsigned long long) sqe->off,
(unsigned long long) sqe->addr, sqe->rw_flags,
sqe->buf_index, sqe->user_data);
if (sq_shift) {
u64 *sqeb = (void *) (sqe + 1);
int size = sizeof(struct io_uring_sqe) / sizeof(u64);
int j;
for (j = 0; j < size; j++) {
seq_printf(m, ", e%d:0x%llx", j,
(unsigned long long) *sqeb);
sqeb++;
}
}
seq_printf(m, "\n");
}
seq_printf(m, "CQEs:\t%u\n", cq_tail - cq_head);
cq_entries = min(cq_tail - cq_head, ctx->cq_entries);
for (i = 0; i < cq_entries; i++) {
unsigned int entry = i + cq_head;
struct io_uring_cqe *cqe = &r->cqes[(entry & cq_mask) << cq_shift];
seq_printf(m, "%5u: user_data:%llu, res:%d, flag:%x",
entry & cq_mask, cqe->user_data, cqe->res,
cqe->flags);
if (cq_shift)
seq_printf(m, ", extra1:%llu, extra2:%llu\n",
cqe->big_cqe[0], cqe->big_cqe[1]);
seq_printf(m, "\n");
}
/*
* Avoid ABBA deadlock between the seq lock and the io_uring mutex,
* since fdinfo case grabs it in the opposite direction of normal use
* cases. If we fail to get the lock, we just don't iterate any
* structures that could be going away outside the io_uring mutex.
*/
has_lock = mutex_trylock(&ctx->uring_lock);
if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) {
sq = ctx->sq_data;
if (!sq->thread)
sq = NULL;
}
seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);
seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
struct file *f = io_file_from_index(&ctx->file_table, i);
if (f)
seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);
else
seq_printf(m, "%5u: <none>\n", i);
}
seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);
for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {
struct io_mapped_ubuf *buf = ctx->user_bufs[i];
unsigned int len = buf->ubuf_end - buf->ubuf;
seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, len);
}
if (has_lock && !xa_empty(&ctx->personalities)) {
unsigned long index;
const struct cred *cred;
seq_printf(m, "Personalities:\n");
xa_for_each(&ctx->personalities, index, cred)
io_uring_show_cred(m, index, cred);
}
seq_puts(m, "PollList:\n");
for (i = 0; i < (1U << ctx->cancel_table.hash_bits); i++) {
struct io_hash_bucket *hb = &ctx->cancel_table.hbs[i];
struct io_hash_bucket *hbl = &ctx->cancel_table_locked.hbs[i];
struct io_kiocb *req;
spin_lock(&hb->lock);
hlist_for_each_entry(req, &hb->list, hash_node)
seq_printf(m, " op=%d, task_works=%d\n", req->opcode,
task_work_pending(req->task));
spin_unlock(&hb->lock);
if (!has_lock)
continue;
hlist_for_each_entry(req, &hbl->list, hash_node)
seq_printf(m, " op=%d, task_works=%d\n", req->opcode,
task_work_pending(req->task));
}
if (has_lock)
mutex_unlock(&ctx->uring_lock);
seq_puts(m, "CqOverflowList:\n");
spin_lock(&ctx->completion_lock);
list_for_each_entry(ocqe, &ctx->cq_overflow_list, list) {
struct io_uring_cqe *cqe = &ocqe->cqe;
seq_printf(m, " user_data=%llu, res=%d, flags=%x\n",
cqe->user_data, cqe->res, cqe->flags);
}
spin_unlock(&ctx->completion_lock);
}
#endif
| linux-master | io_uring/fdinfo.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <linux/fsnotify.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "sync.h"
struct io_sync {
struct file *file;
loff_t len;
loff_t off;
int flags;
int mode;
};
int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in))
return -EINVAL;
sync->off = READ_ONCE(sqe->off);
sync->len = READ_ONCE(sqe->len);
sync->flags = READ_ONCE(sqe->sync_range_flags);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
int ret;
/* sync_file_range always requires a blocking context */
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = sync_file_range(req->file, sync->off, sync->len, sync->flags);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in))
return -EINVAL;
sync->flags = READ_ONCE(sqe->fsync_flags);
if (unlikely(sync->flags & ~IORING_FSYNC_DATASYNC))
return -EINVAL;
sync->off = READ_ONCE(sqe->off);
sync->len = READ_ONCE(sqe->len);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_fsync(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
loff_t end = sync->off + sync->len;
int ret;
/* fsync always requires a blocking context */
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = vfs_fsync_range(req->file, sync->off, end > 0 ? end : LLONG_MAX,
sync->flags & IORING_FSYNC_DATASYNC);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
if (sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
return -EINVAL;
sync->off = READ_ONCE(sqe->off);
sync->len = READ_ONCE(sqe->addr);
sync->mode = READ_ONCE(sqe->len);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_fallocate(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
int ret;
/* fallocate always requiring blocking context */
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = vfs_fallocate(req->file, sync->mode, sync->off, sync->len);
if (ret >= 0)
fsnotify_modify(req->file);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
| linux-master | io_uring/sync.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "../fs/internal.h"
#include "io_uring.h"
#include "statx.h"
struct io_statx {
struct file *file;
int dfd;
unsigned int mask;
unsigned int flags;
struct filename *filename;
struct statx __user *buffer;
};
int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_statx *sx = io_kiocb_to_cmd(req, struct io_statx);
const char __user *path;
if (sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
sx->dfd = READ_ONCE(sqe->fd);
sx->mask = READ_ONCE(sqe->len);
path = u64_to_user_ptr(READ_ONCE(sqe->addr));
sx->buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2));
sx->flags = READ_ONCE(sqe->statx_flags);
sx->filename = getname_flags(path,
getname_statx_lookup_flags(sx->flags),
NULL);
if (IS_ERR(sx->filename)) {
int ret = PTR_ERR(sx->filename);
sx->filename = NULL;
return ret;
}
req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_statx(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_statx *sx = io_kiocb_to_cmd(req, struct io_statx);
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
ret = do_statx(sx->dfd, sx->filename, sx->flags, sx->mask, sx->buffer);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void io_statx_cleanup(struct io_kiocb *req)
{
struct io_statx *sx = io_kiocb_to_cmd(req, struct io_statx);
if (sx->filename)
putname(sx->filename);
}
| linux-master | io_uring/statx.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/compat.h>
#include <net/compat.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "kbuf.h"
#include "alloc_cache.h"
#include "net.h"
#include "notif.h"
#include "rsrc.h"
#if defined(CONFIG_NET)
struct io_shutdown {
struct file *file;
int how;
};
struct io_accept {
struct file *file;
struct sockaddr __user *addr;
int __user *addr_len;
int flags;
u32 file_slot;
unsigned long nofile;
};
struct io_socket {
struct file *file;
int domain;
int type;
int protocol;
int flags;
u32 file_slot;
unsigned long nofile;
};
struct io_connect {
struct file *file;
struct sockaddr __user *addr;
int addr_len;
bool in_progress;
bool seen_econnaborted;
};
struct io_sr_msg {
struct file *file;
union {
struct compat_msghdr __user *umsg_compat;
struct user_msghdr __user *umsg;
void __user *buf;
};
unsigned len;
unsigned done_io;
unsigned msg_flags;
u16 flags;
/* initialised and used only by !msg send variants */
u16 addr_len;
u16 buf_group;
void __user *addr;
void __user *msg_control;
/* used only for send zerocopy */
struct io_kiocb *notif;
};
static inline bool io_check_multishot(struct io_kiocb *req,
unsigned int issue_flags)
{
/*
* When ->locked_cq is set we only allow to post CQEs from the original
* task context. Usual request completions will be handled in other
* generic paths but multipoll may decide to post extra cqes.
*/
return !(issue_flags & IO_URING_F_IOWQ) ||
!(issue_flags & IO_URING_F_MULTISHOT) ||
!req->ctx->task_complete;
}
int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
sqe->buf_index || sqe->splice_fd_in))
return -EINVAL;
shutdown->how = READ_ONCE(sqe->len);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
struct socket *sock;
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
ret = __sys_shutdown_sock(sock, shutdown->how);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
static bool io_net_retry(struct socket *sock, int flags)
{
if (!(flags & MSG_WAITALL))
return false;
return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
}
static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_async_msghdr *hdr = req->async_data;
if (!req_has_async_data(req) || issue_flags & IO_URING_F_UNLOCKED)
return;
/* Let normal cleanup path reap it if we fail adding to the cache */
if (io_alloc_cache_put(&req->ctx->netmsg_cache, &hdr->cache)) {
req->async_data = NULL;
req->flags &= ~REQ_F_ASYNC_DATA;
}
}
static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req,
unsigned int issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_cache_entry *entry;
struct io_async_msghdr *hdr;
if (!(issue_flags & IO_URING_F_UNLOCKED)) {
entry = io_alloc_cache_get(&ctx->netmsg_cache);
if (entry) {
hdr = container_of(entry, struct io_async_msghdr, cache);
hdr->free_iov = NULL;
req->flags |= REQ_F_ASYNC_DATA;
req->async_data = hdr;
return hdr;
}
}
if (!io_alloc_async_data(req)) {
hdr = req->async_data;
hdr->free_iov = NULL;
return hdr;
}
return NULL;
}
static inline struct io_async_msghdr *io_msg_alloc_async_prep(struct io_kiocb *req)
{
/* ->prep_async is always called from the submission context */
return io_msg_alloc_async(req, 0);
}
static int io_setup_async_msg(struct io_kiocb *req,
struct io_async_msghdr *kmsg,
unsigned int issue_flags)
{
struct io_async_msghdr *async_msg;
if (req_has_async_data(req))
return -EAGAIN;
async_msg = io_msg_alloc_async(req, issue_flags);
if (!async_msg) {
kfree(kmsg->free_iov);
return -ENOMEM;
}
req->flags |= REQ_F_NEED_CLEANUP;
memcpy(async_msg, kmsg, sizeof(*kmsg));
if (async_msg->msg.msg_name)
async_msg->msg.msg_name = &async_msg->addr;
if ((req->flags & REQ_F_BUFFER_SELECT) && !async_msg->msg.msg_iter.nr_segs)
return -EAGAIN;
/* if were using fast_iov, set it to the new one */
if (iter_is_iovec(&kmsg->msg.msg_iter) && !kmsg->free_iov) {
size_t fast_idx = iter_iov(&kmsg->msg.msg_iter) - kmsg->fast_iov;
async_msg->msg.msg_iter.__iov = &async_msg->fast_iov[fast_idx];
}
return -EAGAIN;
}
static int io_sendmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
int ret;
iomsg->msg.msg_name = &iomsg->addr;
iomsg->free_iov = iomsg->fast_iov;
ret = sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
&iomsg->free_iov);
/* save msg_control as sys_sendmsg() overwrites it */
sr->msg_control = iomsg->msg.msg_control_user;
return ret;
}
int io_send_prep_async(struct io_kiocb *req)
{
struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *io;
int ret;
if (!zc->addr || req_has_async_data(req))
return 0;
io = io_msg_alloc_async_prep(req);
if (!io)
return -ENOMEM;
ret = move_addr_to_kernel(zc->addr, zc->addr_len, &io->addr);
return ret;
}
static int io_setup_async_addr(struct io_kiocb *req,
struct sockaddr_storage *addr_storage,
unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *io;
if (!sr->addr || req_has_async_data(req))
return -EAGAIN;
io = io_msg_alloc_async(req, issue_flags);
if (!io)
return -ENOMEM;
memcpy(&io->addr, addr_storage, sizeof(io->addr));
return -EAGAIN;
}
int io_sendmsg_prep_async(struct io_kiocb *req)
{
int ret;
if (!io_msg_alloc_async_prep(req))
return -ENOMEM;
ret = io_sendmsg_copy_hdr(req, req->async_data);
if (!ret)
req->flags |= REQ_F_NEED_CLEANUP;
return ret;
}
void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
{
struct io_async_msghdr *io = req->async_data;
kfree(io->free_iov);
}
int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
if (req->opcode == IORING_OP_SEND) {
if (READ_ONCE(sqe->__pad3[0]))
return -EINVAL;
sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
sr->addr_len = READ_ONCE(sqe->addr_len);
} else if (sqe->addr2 || sqe->file_index) {
return -EINVAL;
}
sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
sr->flags = READ_ONCE(sqe->ioprio);
if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
return -EINVAL;
sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
if (sr->msg_flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
sr->msg_flags |= MSG_CMSG_COMPAT;
#endif
sr->done_io = 0;
return 0;
}
int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr iomsg, *kmsg;
struct socket *sock;
unsigned flags;
int min_ret = 0;
int ret;
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
if (req_has_async_data(req)) {
kmsg = req->async_data;
kmsg->msg.msg_control_user = sr->msg_control;
} else {
ret = io_sendmsg_copy_hdr(req, &iomsg);
if (ret)
return ret;
kmsg = &iomsg;
}
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return io_setup_async_msg(req, kmsg, issue_flags);
flags = sr->msg_flags;
if (issue_flags & IO_URING_F_NONBLOCK)
flags |= MSG_DONTWAIT;
if (flags & MSG_WAITALL)
min_ret = iov_iter_count(&kmsg->msg.msg_iter);
ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
if (ret < min_ret) {
if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
return io_setup_async_msg(req, kmsg, issue_flags);
if (ret > 0 && io_net_retry(sock, flags)) {
kmsg->msg.msg_controllen = 0;
kmsg->msg.msg_control = NULL;
sr->done_io += ret;
req->flags |= REQ_F_PARTIAL_IO;
return io_setup_async_msg(req, kmsg, issue_flags);
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
}
/* fast path, check for non-NULL to avoid function call */
if (kmsg->free_iov)
kfree(kmsg->free_iov);
req->flags &= ~REQ_F_NEED_CLEANUP;
io_netmsg_recycle(req, issue_flags);
if (ret >= 0)
ret += sr->done_io;
else if (sr->done_io)
ret = sr->done_io;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_send(struct io_kiocb *req, unsigned int issue_flags)
{
struct sockaddr_storage __address;
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct msghdr msg;
struct socket *sock;
unsigned flags;
int min_ret = 0;
int ret;
msg.msg_name = NULL;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_namelen = 0;
msg.msg_ubuf = NULL;
if (sr->addr) {
if (req_has_async_data(req)) {
struct io_async_msghdr *io = req->async_data;
msg.msg_name = &io->addr;
} else {
ret = move_addr_to_kernel(sr->addr, sr->addr_len, &__address);
if (unlikely(ret < 0))
return ret;
msg.msg_name = (struct sockaddr *)&__address;
}
msg.msg_namelen = sr->addr_len;
}
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return io_setup_async_addr(req, &__address, issue_flags);
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len, &msg.msg_iter);
if (unlikely(ret))
return ret;
flags = sr->msg_flags;
if (issue_flags & IO_URING_F_NONBLOCK)
flags |= MSG_DONTWAIT;
if (flags & MSG_WAITALL)
min_ret = iov_iter_count(&msg.msg_iter);
flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
msg.msg_flags = flags;
ret = sock_sendmsg(sock, &msg);
if (ret < min_ret) {
if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
return io_setup_async_addr(req, &__address, issue_flags);
if (ret > 0 && io_net_retry(sock, flags)) {
sr->len -= ret;
sr->buf += ret;
sr->done_io += ret;
req->flags |= REQ_F_PARTIAL_IO;
return io_setup_async_addr(req, &__address, issue_flags);
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
}
if (ret >= 0)
ret += sr->done_io;
else if (sr->done_io)
ret = sr->done_io;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
{
int hdr;
if (iomsg->namelen < 0)
return true;
if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
iomsg->namelen, &hdr))
return true;
if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
return true;
return false;
}
static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct user_msghdr msg;
int ret;
if (copy_from_user(&msg, sr->umsg, sizeof(*sr->umsg)))
return -EFAULT;
ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
if (ret)
return ret;
if (req->flags & REQ_F_BUFFER_SELECT) {
if (msg.msg_iovlen == 0) {
sr->len = iomsg->fast_iov[0].iov_len = 0;
iomsg->fast_iov[0].iov_base = NULL;
iomsg->free_iov = NULL;
} else if (msg.msg_iovlen > 1) {
return -EINVAL;
} else {
if (copy_from_user(iomsg->fast_iov, msg.msg_iov, sizeof(*msg.msg_iov)))
return -EFAULT;
sr->len = iomsg->fast_iov[0].iov_len;
iomsg->free_iov = NULL;
}
if (req->flags & REQ_F_APOLL_MULTISHOT) {
iomsg->namelen = msg.msg_namelen;
iomsg->controllen = msg.msg_controllen;
if (io_recvmsg_multishot_overflow(iomsg))
return -EOVERFLOW;
}
} else {
iomsg->free_iov = iomsg->fast_iov;
ret = __import_iovec(ITER_DEST, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
&iomsg->free_iov, &iomsg->msg.msg_iter,
false);
if (ret > 0)
ret = 0;
}
return ret;
}
#ifdef CONFIG_COMPAT
static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct compat_msghdr msg;
struct compat_iovec __user *uiov;
int ret;
if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
return -EFAULT;
ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
if (ret)
return ret;
uiov = compat_ptr(msg.msg_iov);
if (req->flags & REQ_F_BUFFER_SELECT) {
compat_ssize_t clen;
iomsg->free_iov = NULL;
if (msg.msg_iovlen == 0) {
sr->len = 0;
} else if (msg.msg_iovlen > 1) {
return -EINVAL;
} else {
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(clen, &uiov->iov_len))
return -EFAULT;
if (clen < 0)
return -EINVAL;
sr->len = clen;
}
if (req->flags & REQ_F_APOLL_MULTISHOT) {
iomsg->namelen = msg.msg_namelen;
iomsg->controllen = msg.msg_controllen;
if (io_recvmsg_multishot_overflow(iomsg))
return -EOVERFLOW;
}
} else {
iomsg->free_iov = iomsg->fast_iov;
ret = __import_iovec(ITER_DEST, (struct iovec __user *)uiov, msg.msg_iovlen,
UIO_FASTIOV, &iomsg->free_iov,
&iomsg->msg.msg_iter, true);
if (ret < 0)
return ret;
}
return 0;
}
#endif
static int io_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
iomsg->msg.msg_name = &iomsg->addr;
iomsg->msg.msg_iter.nr_segs = 0;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return __io_compat_recvmsg_copy_hdr(req, iomsg);
#endif
return __io_recvmsg_copy_hdr(req, iomsg);
}
int io_recvmsg_prep_async(struct io_kiocb *req)
{
int ret;
if (!io_msg_alloc_async_prep(req))
return -ENOMEM;
ret = io_recvmsg_copy_hdr(req, req->async_data);
if (!ret)
req->flags |= REQ_F_NEED_CLEANUP;
return ret;
}
#define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT)
int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
if (unlikely(sqe->file_index || sqe->addr2))
return -EINVAL;
sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
sr->flags = READ_ONCE(sqe->ioprio);
if (sr->flags & ~(RECVMSG_FLAGS))
return -EINVAL;
sr->msg_flags = READ_ONCE(sqe->msg_flags);
if (sr->msg_flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
if (sr->msg_flags & MSG_ERRQUEUE)
req->flags |= REQ_F_CLEAR_POLLIN;
if (sr->flags & IORING_RECV_MULTISHOT) {
if (!(req->flags & REQ_F_BUFFER_SELECT))
return -EINVAL;
if (sr->msg_flags & MSG_WAITALL)
return -EINVAL;
if (req->opcode == IORING_OP_RECV && sr->len)
return -EINVAL;
req->flags |= REQ_F_APOLL_MULTISHOT;
/*
* Store the buffer group for this multishot receive separately,
* as if we end up doing an io-wq based issue that selects a
* buffer, it has to be committed immediately and that will
* clear ->buf_list. This means we lose the link to the buffer
* list, and the eventual buffer put on completion then cannot
* restore it.
*/
sr->buf_group = req->buf_index;
}
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
sr->msg_flags |= MSG_CMSG_COMPAT;
#endif
sr->done_io = 0;
return 0;
}
static inline void io_recv_prep_retry(struct io_kiocb *req)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
sr->done_io = 0;
sr->len = 0; /* get from the provided buffer */
req->buf_index = sr->buf_group;
}
/*
* Finishes io_recv and io_recvmsg.
*
* Returns true if it is actually finished, or false if it should run
* again (for multishot).
*/
static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
struct msghdr *msg, bool mshot_finished,
unsigned issue_flags)
{
unsigned int cflags;
cflags = io_put_kbuf(req, issue_flags);
if (msg->msg_inq && msg->msg_inq != -1)
cflags |= IORING_CQE_F_SOCK_NONEMPTY;
if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
io_req_set_res(req, *ret, cflags);
*ret = IOU_OK;
return true;
}
if (!mshot_finished) {
if (io_fill_cqe_req_aux(req, issue_flags & IO_URING_F_COMPLETE_DEFER,
*ret, cflags | IORING_CQE_F_MORE)) {
io_recv_prep_retry(req);
/* Known not-empty or unknown state, retry */
if (cflags & IORING_CQE_F_SOCK_NONEMPTY ||
msg->msg_inq == -1)
return false;
if (issue_flags & IO_URING_F_MULTISHOT)
*ret = IOU_ISSUE_SKIP_COMPLETE;
else
*ret = -EAGAIN;
return true;
}
/* Otherwise stop multishot but use the current result. */
}
io_req_set_res(req, *ret, cflags);
if (issue_flags & IO_URING_F_MULTISHOT)
*ret = IOU_STOP_MULTISHOT;
else
*ret = IOU_OK;
return true;
}
static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
struct io_sr_msg *sr, void __user **buf,
size_t *len)
{
unsigned long ubuf = (unsigned long) *buf;
unsigned long hdr;
hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
kmsg->controllen;
if (*len < hdr)
return -EFAULT;
if (kmsg->controllen) {
unsigned long control = ubuf + hdr - kmsg->controllen;
kmsg->msg.msg_control_user = (void __user *) control;
kmsg->msg.msg_controllen = kmsg->controllen;
}
sr->buf = *buf; /* stash for later copy */
*buf = (void __user *) (ubuf + hdr);
kmsg->payloadlen = *len = *len - hdr;
return 0;
}
struct io_recvmsg_multishot_hdr {
struct io_uring_recvmsg_out msg;
struct sockaddr_storage addr;
};
static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
struct io_async_msghdr *kmsg,
unsigned int flags, bool *finished)
{
int err;
int copy_len;
struct io_recvmsg_multishot_hdr hdr;
if (kmsg->namelen)
kmsg->msg.msg_name = &hdr.addr;
kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
kmsg->msg.msg_namelen = 0;
if (sock->file->f_flags & O_NONBLOCK)
flags |= MSG_DONTWAIT;
err = sock_recvmsg(sock, &kmsg->msg, flags);
*finished = err <= 0;
if (err < 0)
return err;
hdr.msg = (struct io_uring_recvmsg_out) {
.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
};
hdr.msg.payloadlen = err;
if (err > kmsg->payloadlen)
err = kmsg->payloadlen;
copy_len = sizeof(struct io_uring_recvmsg_out);
if (kmsg->msg.msg_namelen > kmsg->namelen)
copy_len += kmsg->namelen;
else
copy_len += kmsg->msg.msg_namelen;
/*
* "fromlen shall refer to the value before truncation.."
* 1003.1g
*/
hdr.msg.namelen = kmsg->msg.msg_namelen;
/* ensure that there is no gap between hdr and sockaddr_storage */
BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
sizeof(struct io_uring_recvmsg_out));
if (copy_to_user(io->buf, &hdr, copy_len)) {
*finished = true;
return -EFAULT;
}
return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
kmsg->controllen + err;
}
int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr iomsg, *kmsg;
struct socket *sock;
unsigned flags;
int ret, min_ret = 0;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
bool mshot_finished = true;
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
if (req_has_async_data(req)) {
kmsg = req->async_data;
} else {
ret = io_recvmsg_copy_hdr(req, &iomsg);
if (ret)
return ret;
kmsg = &iomsg;
}
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return io_setup_async_msg(req, kmsg, issue_flags);
if (!io_check_multishot(req, issue_flags))
return io_setup_async_msg(req, kmsg, issue_flags);
retry_multishot:
if (io_do_buffer_select(req)) {
void __user *buf;
size_t len = sr->len;
buf = io_buffer_select(req, &len, issue_flags);
if (!buf)
return -ENOBUFS;
if (req->flags & REQ_F_APOLL_MULTISHOT) {
ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
if (ret) {
io_kbuf_recycle(req, issue_flags);
return ret;
}
}
iov_iter_ubuf(&kmsg->msg.msg_iter, ITER_DEST, buf, len);
}
flags = sr->msg_flags;
if (force_nonblock)
flags |= MSG_DONTWAIT;
kmsg->msg.msg_get_inq = 1;
kmsg->msg.msg_inq = -1;
if (req->flags & REQ_F_APOLL_MULTISHOT) {
ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
&mshot_finished);
} else {
/* disable partial retry for recvmsg with cmsg attached */
if (flags & MSG_WAITALL && !kmsg->msg.msg_controllen)
min_ret = iov_iter_count(&kmsg->msg.msg_iter);
ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg,
kmsg->uaddr, flags);
}
if (ret < min_ret) {
if (ret == -EAGAIN && force_nonblock) {
ret = io_setup_async_msg(req, kmsg, issue_flags);
if (ret == -EAGAIN && (issue_flags & IO_URING_F_MULTISHOT)) {
io_kbuf_recycle(req, issue_flags);
return IOU_ISSUE_SKIP_COMPLETE;
}
return ret;
}
if (ret > 0 && io_net_retry(sock, flags)) {
sr->done_io += ret;
req->flags |= REQ_F_PARTIAL_IO;
return io_setup_async_msg(req, kmsg, issue_flags);
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
req_set_fail(req);
}
if (ret > 0)
ret += sr->done_io;
else if (sr->done_io)
ret = sr->done_io;
else
io_kbuf_recycle(req, issue_flags);
if (!io_recv_finish(req, &ret, &kmsg->msg, mshot_finished, issue_flags))
goto retry_multishot;
if (mshot_finished) {
/* fast path, check for non-NULL to avoid function call */
if (kmsg->free_iov)
kfree(kmsg->free_iov);
io_netmsg_recycle(req, issue_flags);
req->flags &= ~REQ_F_NEED_CLEANUP;
}
return ret;
}
int io_recv(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct msghdr msg;
struct socket *sock;
unsigned flags;
int ret, min_ret = 0;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
size_t len = sr->len;
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return -EAGAIN;
if (!io_check_multishot(req, issue_flags))
return -EAGAIN;
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_control = NULL;
msg.msg_get_inq = 1;
msg.msg_controllen = 0;
msg.msg_iocb = NULL;
msg.msg_ubuf = NULL;
retry_multishot:
if (io_do_buffer_select(req)) {
void __user *buf;
buf = io_buffer_select(req, &len, issue_flags);
if (!buf)
return -ENOBUFS;
sr->buf = buf;
}
ret = import_ubuf(ITER_DEST, sr->buf, len, &msg.msg_iter);
if (unlikely(ret))
goto out_free;
msg.msg_inq = -1;
msg.msg_flags = 0;
flags = sr->msg_flags;
if (force_nonblock)
flags |= MSG_DONTWAIT;
if (flags & MSG_WAITALL)
min_ret = iov_iter_count(&msg.msg_iter);
ret = sock_recvmsg(sock, &msg, flags);
if (ret < min_ret) {
if (ret == -EAGAIN && force_nonblock) {
if (issue_flags & IO_URING_F_MULTISHOT) {
io_kbuf_recycle(req, issue_flags);
return IOU_ISSUE_SKIP_COMPLETE;
}
return -EAGAIN;
}
if (ret > 0 && io_net_retry(sock, flags)) {
sr->len -= ret;
sr->buf += ret;
sr->done_io += ret;
req->flags |= REQ_F_PARTIAL_IO;
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
out_free:
req_set_fail(req);
}
if (ret > 0)
ret += sr->done_io;
else if (sr->done_io)
ret = sr->done_io;
else
io_kbuf_recycle(req, issue_flags);
if (!io_recv_finish(req, &ret, &msg, ret <= 0, issue_flags))
goto retry_multishot;
return ret;
}
void io_send_zc_cleanup(struct io_kiocb *req)
{
struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *io;
if (req_has_async_data(req)) {
io = req->async_data;
/* might be ->fast_iov if *msg_copy_hdr failed */
if (io->free_iov != io->fast_iov)
kfree(io->free_iov);
}
if (zc->notif) {
io_notif_flush(zc->notif);
zc->notif = NULL;
}
}
#define IO_ZC_FLAGS_COMMON (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_FIXED_BUF)
#define IO_ZC_FLAGS_VALID (IO_ZC_FLAGS_COMMON | IORING_SEND_ZC_REPORT_USAGE)
int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *notif;
if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)))
return -EINVAL;
/* we don't support IOSQE_CQE_SKIP_SUCCESS just yet */
if (req->flags & REQ_F_CQE_SKIP)
return -EINVAL;
notif = zc->notif = io_alloc_notif(ctx);
if (!notif)
return -ENOMEM;
notif->cqe.user_data = req->cqe.user_data;
notif->cqe.res = 0;
notif->cqe.flags = IORING_CQE_F_NOTIF;
req->flags |= REQ_F_NEED_CLEANUP;
zc->flags = READ_ONCE(sqe->ioprio);
if (unlikely(zc->flags & ~IO_ZC_FLAGS_COMMON)) {
if (zc->flags & ~IO_ZC_FLAGS_VALID)
return -EINVAL;
if (zc->flags & IORING_SEND_ZC_REPORT_USAGE) {
io_notif_set_extended(notif);
io_notif_to_data(notif)->zc_report = true;
}
}
if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
unsigned idx = READ_ONCE(sqe->buf_index);
if (unlikely(idx >= ctx->nr_user_bufs))
return -EFAULT;
idx = array_index_nospec(idx, ctx->nr_user_bufs);
req->imu = READ_ONCE(ctx->user_bufs[idx]);
io_req_set_rsrc_node(notif, ctx, 0);
}
if (req->opcode == IORING_OP_SEND_ZC) {
if (READ_ONCE(sqe->__pad3[0]))
return -EINVAL;
zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
zc->addr_len = READ_ONCE(sqe->addr_len);
} else {
if (unlikely(sqe->addr2 || sqe->file_index))
return -EINVAL;
if (unlikely(zc->flags & IORING_RECVSEND_FIXED_BUF))
return -EINVAL;
}
zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
zc->len = READ_ONCE(sqe->len);
zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
if (zc->msg_flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
zc->done_io = 0;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
zc->msg_flags |= MSG_CMSG_COMPAT;
#endif
return 0;
}
static int io_sg_from_iter_iovec(struct sock *sk, struct sk_buff *skb,
struct iov_iter *from, size_t length)
{
skb_zcopy_downgrade_managed(skb);
return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
}
static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
struct iov_iter *from, size_t length)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
int frag = shinfo->nr_frags;
int ret = 0;
struct bvec_iter bi;
ssize_t copied = 0;
unsigned long truesize = 0;
if (!frag)
shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
else if (unlikely(!skb_zcopy_managed(skb)))
return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
bi.bi_size = min(from->count, length);
bi.bi_bvec_done = from->iov_offset;
bi.bi_idx = 0;
while (bi.bi_size && frag < MAX_SKB_FRAGS) {
struct bio_vec v = mp_bvec_iter_bvec(from->bvec, bi);
copied += v.bv_len;
truesize += PAGE_ALIGN(v.bv_len + v.bv_offset);
__skb_fill_page_desc_noacc(shinfo, frag++, v.bv_page,
v.bv_offset, v.bv_len);
bvec_iter_advance_single(from->bvec, &bi, v.bv_len);
}
if (bi.bi_size)
ret = -EMSGSIZE;
shinfo->nr_frags = frag;
from->bvec += bi.bi_idx;
from->nr_segs -= bi.bi_idx;
from->count -= copied;
from->iov_offset = bi.bi_bvec_done;
skb->data_len += copied;
skb->len += copied;
skb->truesize += truesize;
if (sk && sk->sk_type == SOCK_STREAM) {
sk_wmem_queued_add(sk, truesize);
if (!skb_zcopy_pure(skb))
sk_mem_charge(sk, truesize);
} else {
refcount_add(truesize, &skb->sk->sk_wmem_alloc);
}
return ret;
}
int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
{
struct sockaddr_storage __address;
struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
struct msghdr msg;
struct socket *sock;
unsigned msg_flags;
int ret, min_ret = 0;
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
return -EOPNOTSUPP;
msg.msg_name = NULL;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_namelen = 0;
if (zc->addr) {
if (req_has_async_data(req)) {
struct io_async_msghdr *io = req->async_data;
msg.msg_name = &io->addr;
} else {
ret = move_addr_to_kernel(zc->addr, zc->addr_len, &__address);
if (unlikely(ret < 0))
return ret;
msg.msg_name = (struct sockaddr *)&__address;
}
msg.msg_namelen = zc->addr_len;
}
if (!(req->flags & REQ_F_POLLED) &&
(zc->flags & IORING_RECVSEND_POLL_FIRST))
return io_setup_async_addr(req, &__address, issue_flags);
if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
ret = io_import_fixed(ITER_SOURCE, &msg.msg_iter, req->imu,
(u64)(uintptr_t)zc->buf, zc->len);
if (unlikely(ret))
return ret;
msg.sg_from_iter = io_sg_from_iter;
} else {
io_notif_set_extended(zc->notif);
ret = import_ubuf(ITER_SOURCE, zc->buf, zc->len, &msg.msg_iter);
if (unlikely(ret))
return ret;
ret = io_notif_account_mem(zc->notif, zc->len);
if (unlikely(ret))
return ret;
msg.sg_from_iter = io_sg_from_iter_iovec;
}
msg_flags = zc->msg_flags | MSG_ZEROCOPY;
if (issue_flags & IO_URING_F_NONBLOCK)
msg_flags |= MSG_DONTWAIT;
if (msg_flags & MSG_WAITALL)
min_ret = iov_iter_count(&msg.msg_iter);
msg_flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
msg.msg_flags = msg_flags;
msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;
ret = sock_sendmsg(sock, &msg);
if (unlikely(ret < min_ret)) {
if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
return io_setup_async_addr(req, &__address, issue_flags);
if (ret > 0 && io_net_retry(sock, msg.msg_flags)) {
zc->len -= ret;
zc->buf += ret;
zc->done_io += ret;
req->flags |= REQ_F_PARTIAL_IO;
return io_setup_async_addr(req, &__address, issue_flags);
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
}
if (ret >= 0)
ret += zc->done_io;
else if (zc->done_io)
ret = zc->done_io;
/*
* If we're in io-wq we can't rely on tw ordering guarantees, defer
* flushing notif to io_send_zc_cleanup()
*/
if (!(issue_flags & IO_URING_F_UNLOCKED)) {
io_notif_flush(zc->notif);
req->flags &= ~REQ_F_NEED_CLEANUP;
}
io_req_set_res(req, ret, IORING_CQE_F_MORE);
return IOU_OK;
}
int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr iomsg, *kmsg;
struct socket *sock;
unsigned flags;
int ret, min_ret = 0;
io_notif_set_extended(sr->notif);
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
return -EOPNOTSUPP;
if (req_has_async_data(req)) {
kmsg = req->async_data;
} else {
ret = io_sendmsg_copy_hdr(req, &iomsg);
if (ret)
return ret;
kmsg = &iomsg;
}
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return io_setup_async_msg(req, kmsg, issue_flags);
flags = sr->msg_flags | MSG_ZEROCOPY;
if (issue_flags & IO_URING_F_NONBLOCK)
flags |= MSG_DONTWAIT;
if (flags & MSG_WAITALL)
min_ret = iov_iter_count(&kmsg->msg.msg_iter);
kmsg->msg.msg_ubuf = &io_notif_to_data(sr->notif)->uarg;
kmsg->msg.sg_from_iter = io_sg_from_iter_iovec;
ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
if (unlikely(ret < min_ret)) {
if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
return io_setup_async_msg(req, kmsg, issue_flags);
if (ret > 0 && io_net_retry(sock, flags)) {
sr->done_io += ret;
req->flags |= REQ_F_PARTIAL_IO;
return io_setup_async_msg(req, kmsg, issue_flags);
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
}
/* fast path, check for non-NULL to avoid function call */
if (kmsg->free_iov) {
kfree(kmsg->free_iov);
kmsg->free_iov = NULL;
}
io_netmsg_recycle(req, issue_flags);
if (ret >= 0)
ret += sr->done_io;
else if (sr->done_io)
ret = sr->done_io;
/*
* If we're in io-wq we can't rely on tw ordering guarantees, defer
* flushing notif to io_send_zc_cleanup()
*/
if (!(issue_flags & IO_URING_F_UNLOCKED)) {
io_notif_flush(sr->notif);
req->flags &= ~REQ_F_NEED_CLEANUP;
}
io_req_set_res(req, ret, IORING_CQE_F_MORE);
return IOU_OK;
}
void io_sendrecv_fail(struct io_kiocb *req)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
if (req->flags & REQ_F_PARTIAL_IO)
req->cqe.res = sr->done_io;
if ((req->flags & REQ_F_NEED_CLEANUP) &&
(req->opcode == IORING_OP_SEND_ZC || req->opcode == IORING_OP_SENDMSG_ZC))
req->cqe.flags |= IORING_CQE_F_MORE;
}
int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
unsigned flags;
if (sqe->len || sqe->buf_index)
return -EINVAL;
accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
accept->flags = READ_ONCE(sqe->accept_flags);
accept->nofile = rlimit(RLIMIT_NOFILE);
flags = READ_ONCE(sqe->ioprio);
if (flags & ~IORING_ACCEPT_MULTISHOT)
return -EINVAL;
accept->file_slot = READ_ONCE(sqe->file_index);
if (accept->file_slot) {
if (accept->flags & SOCK_CLOEXEC)
return -EINVAL;
if (flags & IORING_ACCEPT_MULTISHOT &&
accept->file_slot != IORING_FILE_INDEX_ALLOC)
return -EINVAL;
}
if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
return -EINVAL;
if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
if (flags & IORING_ACCEPT_MULTISHOT)
req->flags |= REQ_F_APOLL_MULTISHOT;
return 0;
}
int io_accept(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
bool fixed = !!accept->file_slot;
struct file *file;
int ret, fd;
if (!io_check_multishot(req, issue_flags))
return -EAGAIN;
retry:
if (!fixed) {
fd = __get_unused_fd_flags(accept->flags, accept->nofile);
if (unlikely(fd < 0))
return fd;
}
file = do_accept(req->file, file_flags, accept->addr, accept->addr_len,
accept->flags);
if (IS_ERR(file)) {
if (!fixed)
put_unused_fd(fd);
ret = PTR_ERR(file);
if (ret == -EAGAIN && force_nonblock) {
/*
* if it's multishot and polled, we don't need to
* return EAGAIN to arm the poll infra since it
* has already been done
*/
if (issue_flags & IO_URING_F_MULTISHOT)
ret = IOU_ISSUE_SKIP_COMPLETE;
return ret;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
} else if (!fixed) {
fd_install(fd, file);
ret = fd;
} else {
ret = io_fixed_fd_install(req, issue_flags, file,
accept->file_slot);
}
if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
io_req_set_res(req, ret, 0);
return IOU_OK;
}
if (ret < 0)
return ret;
if (io_fill_cqe_req_aux(req, issue_flags & IO_URING_F_COMPLETE_DEFER,
ret, IORING_CQE_F_MORE))
goto retry;
return -ECANCELED;
}
int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
if (sqe->addr || sqe->rw_flags || sqe->buf_index)
return -EINVAL;
sock->domain = READ_ONCE(sqe->fd);
sock->type = READ_ONCE(sqe->off);
sock->protocol = READ_ONCE(sqe->len);
sock->file_slot = READ_ONCE(sqe->file_index);
sock->nofile = rlimit(RLIMIT_NOFILE);
sock->flags = sock->type & ~SOCK_TYPE_MASK;
if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
return -EINVAL;
if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
return -EINVAL;
return 0;
}
int io_socket(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
bool fixed = !!sock->file_slot;
struct file *file;
int ret, fd;
if (!fixed) {
fd = __get_unused_fd_flags(sock->flags, sock->nofile);
if (unlikely(fd < 0))
return fd;
}
file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
if (IS_ERR(file)) {
if (!fixed)
put_unused_fd(fd);
ret = PTR_ERR(file);
if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
return -EAGAIN;
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
} else if (!fixed) {
fd_install(fd, file);
ret = fd;
} else {
ret = io_fixed_fd_install(req, issue_flags, file,
sock->file_slot);
}
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_connect_prep_async(struct io_kiocb *req)
{
struct io_async_connect *io = req->async_data;
struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
}
int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
return -EINVAL;
conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
conn->addr_len = READ_ONCE(sqe->addr2);
conn->in_progress = conn->seen_econnaborted = false;
return 0;
}
int io_connect(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_connect *connect = io_kiocb_to_cmd(req, struct io_connect);
struct io_async_connect __io, *io;
unsigned file_flags;
int ret;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
if (connect->in_progress) {
struct socket *socket;
ret = -ENOTSOCK;
socket = sock_from_file(req->file);
if (socket)
ret = sock_error(socket->sk);
goto out;
}
if (req_has_async_data(req)) {
io = req->async_data;
} else {
ret = move_addr_to_kernel(connect->addr,
connect->addr_len,
&__io.address);
if (ret)
goto out;
io = &__io;
}
file_flags = force_nonblock ? O_NONBLOCK : 0;
ret = __sys_connect_file(req->file, &io->address,
connect->addr_len, file_flags);
if ((ret == -EAGAIN || ret == -EINPROGRESS || ret == -ECONNABORTED)
&& force_nonblock) {
if (ret == -EINPROGRESS) {
connect->in_progress = true;
return -EAGAIN;
}
if (ret == -ECONNABORTED) {
if (connect->seen_econnaborted)
goto out;
connect->seen_econnaborted = true;
}
if (req_has_async_data(req))
return -EAGAIN;
if (io_alloc_async_data(req)) {
ret = -ENOMEM;
goto out;
}
memcpy(req->async_data, &__io, sizeof(__io));
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
out:
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
void io_netmsg_cache_free(struct io_cache_entry *entry)
{
kfree(container_of(entry, struct io_async_msghdr, cache));
}
#endif
| linux-master | io_uring/net.c |
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/io_uring.h>
#include "io_uring.h"
#include "notif.h"
#include "rsrc.h"
static void io_notif_complete_tw_ext(struct io_kiocb *notif, struct io_tw_state *ts)
{
struct io_notif_data *nd = io_notif_to_data(notif);
struct io_ring_ctx *ctx = notif->ctx;
if (nd->zc_report && (nd->zc_copied || !nd->zc_used))
notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED;
if (nd->account_pages && ctx->user) {
__io_unaccount_mem(ctx->user, nd->account_pages);
nd->account_pages = 0;
}
io_req_task_complete(notif, ts);
}
static void io_tx_ubuf_callback(struct sk_buff *skb, struct ubuf_info *uarg,
bool success)
{
struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);
struct io_kiocb *notif = cmd_to_io_kiocb(nd);
if (refcount_dec_and_test(&uarg->refcnt))
__io_req_task_work_add(notif, IOU_F_TWQ_LAZY_WAKE);
}
static void io_tx_ubuf_callback_ext(struct sk_buff *skb, struct ubuf_info *uarg,
bool success)
{
struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);
if (nd->zc_report) {
if (success && !nd->zc_used && skb)
WRITE_ONCE(nd->zc_used, true);
else if (!success && !nd->zc_copied)
WRITE_ONCE(nd->zc_copied, true);
}
io_tx_ubuf_callback(skb, uarg, success);
}
void io_notif_set_extended(struct io_kiocb *notif)
{
struct io_notif_data *nd = io_notif_to_data(notif);
if (nd->uarg.callback != io_tx_ubuf_callback_ext) {
nd->account_pages = 0;
nd->zc_report = false;
nd->zc_used = false;
nd->zc_copied = false;
nd->uarg.callback = io_tx_ubuf_callback_ext;
notif->io_task_work.func = io_notif_complete_tw_ext;
}
}
struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
struct io_kiocb *notif;
struct io_notif_data *nd;
if (unlikely(!io_alloc_req(ctx, ¬if)))
return NULL;
notif->opcode = IORING_OP_NOP;
notif->flags = 0;
notif->file = NULL;
notif->task = current;
io_get_task_refs(1);
notif->rsrc_node = NULL;
notif->io_task_work.func = io_req_task_complete;
nd = io_notif_to_data(notif);
nd->uarg.flags = IO_NOTIF_UBUF_FLAGS;
nd->uarg.callback = io_tx_ubuf_callback;
refcount_set(&nd->uarg.refcnt, 1);
return notif;
}
| linux-master | io_uring/notif.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io_uring.h>
#include <linux/eventpoll.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "epoll.h"
#if defined(CONFIG_EPOLL)
struct io_epoll {
struct file *file;
int epfd;
int op;
int fd;
struct epoll_event event;
};
int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_epoll *epoll = io_kiocb_to_cmd(req, struct io_epoll);
if (sqe->buf_index || sqe->splice_fd_in)
return -EINVAL;
epoll->epfd = READ_ONCE(sqe->fd);
epoll->op = READ_ONCE(sqe->len);
epoll->fd = READ_ONCE(sqe->off);
if (ep_op_has_event(epoll->op)) {
struct epoll_event __user *ev;
ev = u64_to_user_ptr(READ_ONCE(sqe->addr));
if (copy_from_user(&epoll->event, ev, sizeof(*ev)))
return -EFAULT;
}
return 0;
}
int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_epoll *ie = io_kiocb_to_cmd(req, struct io_epoll);
int ret;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock);
if (force_nonblock && ret == -EAGAIN)
return -EAGAIN;
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
#endif
| linux-master | io_uring/epoll.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "nop.h"
int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return 0;
}
/*
* IORING_OP_NOP just posts a completion event, nothing else.
*/
int io_nop(struct io_kiocb *req, unsigned int issue_flags)
{
io_req_set_res(req, 0, 0);
return IOU_OK;
}
| linux-master | io_uring/nop.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/fsnotify.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "../fs/internal.h"
#include "io_uring.h"
#include "rsrc.h"
#include "openclose.h"
struct io_open {
struct file *file;
int dfd;
u32 file_slot;
struct filename *filename;
struct open_how how;
unsigned long nofile;
};
struct io_close {
struct file *file;
int fd;
u32 file_slot;
};
static bool io_openat_force_async(struct io_open *open)
{
/*
* Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open,
* it'll always -EAGAIN. Note that we test for __O_TMPFILE because
* O_TMPFILE includes O_DIRECTORY, which isn't a flag we need to force
* async for.
*/
return open->how.flags & (O_TRUNC | O_CREAT | __O_TMPFILE);
}
static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
const char __user *fname;
int ret;
if (unlikely(sqe->buf_index))
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
/* open.how should be already initialised */
if (!(open->how.flags & O_PATH) && force_o_largefile())
open->how.flags |= O_LARGEFILE;
open->dfd = READ_ONCE(sqe->fd);
fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
open->filename = getname(fname);
if (IS_ERR(open->filename)) {
ret = PTR_ERR(open->filename);
open->filename = NULL;
return ret;
}
open->file_slot = READ_ONCE(sqe->file_index);
if (open->file_slot && (open->how.flags & O_CLOEXEC))
return -EINVAL;
open->nofile = rlimit(RLIMIT_NOFILE);
req->flags |= REQ_F_NEED_CLEANUP;
if (io_openat_force_async(open))
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
u64 mode = READ_ONCE(sqe->len);
u64 flags = READ_ONCE(sqe->open_flags);
open->how = build_open_how(flags, mode);
return __io_openat_prep(req, sqe);
}
int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
struct open_how __user *how;
size_t len;
int ret;
how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
len = READ_ONCE(sqe->len);
if (len < OPEN_HOW_SIZE_VER0)
return -EINVAL;
ret = copy_struct_from_user(&open->how, sizeof(open->how), how, len);
if (ret)
return ret;
return __io_openat_prep(req, sqe);
}
int io_openat2(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
struct open_flags op;
struct file *file;
bool resolve_nonblock, nonblock_set;
bool fixed = !!open->file_slot;
int ret;
ret = build_open_flags(&open->how, &op);
if (ret)
goto err;
nonblock_set = op.open_flag & O_NONBLOCK;
resolve_nonblock = open->how.resolve & RESOLVE_CACHED;
if (issue_flags & IO_URING_F_NONBLOCK) {
WARN_ON_ONCE(io_openat_force_async(open));
op.lookup_flags |= LOOKUP_CACHED;
op.open_flag |= O_NONBLOCK;
}
if (!fixed) {
ret = __get_unused_fd_flags(open->how.flags, open->nofile);
if (ret < 0)
goto err;
}
file = do_filp_open(open->dfd, open->filename, &op);
if (IS_ERR(file)) {
/*
* We could hang on to this 'fd' on retrying, but seems like
* marginal gain for something that is now known to be a slower
* path. So just put it, and we'll get a new one when we retry.
*/
if (!fixed)
put_unused_fd(ret);
ret = PTR_ERR(file);
/* only retry if RESOLVE_CACHED wasn't already set by application */
if (ret == -EAGAIN &&
(!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK)))
return -EAGAIN;
goto err;
}
if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set)
file->f_flags &= ~O_NONBLOCK;
if (!fixed)
fd_install(ret, file);
else
ret = io_fixed_fd_install(req, issue_flags, file,
open->file_slot);
err:
putname(open->filename);
req->flags &= ~REQ_F_NEED_CLEANUP;
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_openat(struct io_kiocb *req, unsigned int issue_flags)
{
return io_openat2(req, issue_flags);
}
void io_open_cleanup(struct io_kiocb *req)
{
struct io_open *open = io_kiocb_to_cmd(req, struct io_open);
if (open->filename)
putname(open->filename);
}
int __io_close_fixed(struct io_ring_ctx *ctx, unsigned int issue_flags,
unsigned int offset)
{
int ret;
io_ring_submit_lock(ctx, issue_flags);
ret = io_fixed_fd_remove(ctx, offset);
io_ring_submit_unlock(ctx, issue_flags);
return ret;
}
static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
return __io_close_fixed(req->ctx, issue_flags, close->file_slot - 1);
}
int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
if (sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index)
return -EINVAL;
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
close->fd = READ_ONCE(sqe->fd);
close->file_slot = READ_ONCE(sqe->file_index);
if (close->file_slot && close->fd)
return -EINVAL;
return 0;
}
int io_close(struct io_kiocb *req, unsigned int issue_flags)
{
struct files_struct *files = current->files;
struct io_close *close = io_kiocb_to_cmd(req, struct io_close);
struct fdtable *fdt;
struct file *file;
int ret = -EBADF;
if (close->file_slot) {
ret = io_close_fixed(req, issue_flags);
goto err;
}
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
if (close->fd >= fdt->max_fds) {
spin_unlock(&files->file_lock);
goto err;
}
file = rcu_dereference_protected(fdt->fd[close->fd],
lockdep_is_held(&files->file_lock));
if (!file || io_is_uring_fops(file)) {
spin_unlock(&files->file_lock);
goto err;
}
/* if the file has a flush method, be safe and punt to async */
if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) {
spin_unlock(&files->file_lock);
return -EAGAIN;
}
file = __close_fd_get_file(close->fd);
spin_unlock(&files->file_lock);
if (!file)
goto err;
/* No ->flush() or already async, safely close from here */
ret = filp_close(file, current->files);
err:
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
| linux-master | io_uring/openclose.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Contains the core associated with submission side polling of the SQ
* ring, offloading submissions from the application to a kernel thread.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/audit.h>
#include <linux/security.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "sqpoll.h"
#define IORING_SQPOLL_CAP_ENTRIES_VALUE 8
enum {
IO_SQ_THREAD_SHOULD_STOP = 0,
IO_SQ_THREAD_SHOULD_PARK,
};
void io_sq_thread_unpark(struct io_sq_data *sqd)
__releases(&sqd->lock)
{
WARN_ON_ONCE(sqd->thread == current);
/*
* Do the dance but not conditional clear_bit() because it'd race with
* other threads incrementing park_pending and setting the bit.
*/
clear_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
if (atomic_dec_return(&sqd->park_pending))
set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
mutex_unlock(&sqd->lock);
}
void io_sq_thread_park(struct io_sq_data *sqd)
__acquires(&sqd->lock)
{
WARN_ON_ONCE(sqd->thread == current);
atomic_inc(&sqd->park_pending);
set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
mutex_lock(&sqd->lock);
if (sqd->thread)
wake_up_process(sqd->thread);
}
void io_sq_thread_stop(struct io_sq_data *sqd)
{
WARN_ON_ONCE(sqd->thread == current);
WARN_ON_ONCE(test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state));
set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
mutex_lock(&sqd->lock);
if (sqd->thread)
wake_up_process(sqd->thread);
mutex_unlock(&sqd->lock);
wait_for_completion(&sqd->exited);
}
void io_put_sq_data(struct io_sq_data *sqd)
{
if (refcount_dec_and_test(&sqd->refs)) {
WARN_ON_ONCE(atomic_read(&sqd->park_pending));
io_sq_thread_stop(sqd);
kfree(sqd);
}
}
static __cold void io_sqd_update_thread_idle(struct io_sq_data *sqd)
{
struct io_ring_ctx *ctx;
unsigned sq_thread_idle = 0;
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
sq_thread_idle = max(sq_thread_idle, ctx->sq_thread_idle);
sqd->sq_thread_idle = sq_thread_idle;
}
void io_sq_thread_finish(struct io_ring_ctx *ctx)
{
struct io_sq_data *sqd = ctx->sq_data;
if (sqd) {
io_sq_thread_park(sqd);
list_del_init(&ctx->sqd_list);
io_sqd_update_thread_idle(sqd);
io_sq_thread_unpark(sqd);
io_put_sq_data(sqd);
ctx->sq_data = NULL;
}
}
static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p)
{
struct io_ring_ctx *ctx_attach;
struct io_sq_data *sqd;
struct fd f;
f = fdget(p->wq_fd);
if (!f.file)
return ERR_PTR(-ENXIO);
if (!io_is_uring_fops(f.file)) {
fdput(f);
return ERR_PTR(-EINVAL);
}
ctx_attach = f.file->private_data;
sqd = ctx_attach->sq_data;
if (!sqd) {
fdput(f);
return ERR_PTR(-EINVAL);
}
if (sqd->task_tgid != current->tgid) {
fdput(f);
return ERR_PTR(-EPERM);
}
refcount_inc(&sqd->refs);
fdput(f);
return sqd;
}
static struct io_sq_data *io_get_sq_data(struct io_uring_params *p,
bool *attached)
{
struct io_sq_data *sqd;
*attached = false;
if (p->flags & IORING_SETUP_ATTACH_WQ) {
sqd = io_attach_sq_data(p);
if (!IS_ERR(sqd)) {
*attached = true;
return sqd;
}
/* fall through for EPERM case, setup new sqd/task */
if (PTR_ERR(sqd) != -EPERM)
return sqd;
}
sqd = kzalloc(sizeof(*sqd), GFP_KERNEL);
if (!sqd)
return ERR_PTR(-ENOMEM);
atomic_set(&sqd->park_pending, 0);
refcount_set(&sqd->refs, 1);
INIT_LIST_HEAD(&sqd->ctx_list);
mutex_init(&sqd->lock);
init_waitqueue_head(&sqd->wait);
init_completion(&sqd->exited);
return sqd;
}
static inline bool io_sqd_events_pending(struct io_sq_data *sqd)
{
return READ_ONCE(sqd->state);
}
static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
{
unsigned int to_submit;
int ret = 0;
to_submit = io_sqring_entries(ctx);
/* if we're handling multiple rings, cap submit size for fairness */
if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE)
to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE;
if (!wq_list_empty(&ctx->iopoll_list) || to_submit) {
const struct cred *creds = NULL;
if (ctx->sq_creds != current_cred())
creds = override_creds(ctx->sq_creds);
mutex_lock(&ctx->uring_lock);
if (!wq_list_empty(&ctx->iopoll_list))
io_do_iopoll(ctx, true);
/*
* Don't submit if refs are dying, good for io_uring_register(),
* but also it is relied upon by io_ring_exit_work()
*/
if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs)) &&
!(ctx->flags & IORING_SETUP_R_DISABLED))
ret = io_submit_sqes(ctx, to_submit);
mutex_unlock(&ctx->uring_lock);
if (to_submit && wq_has_sleeper(&ctx->sqo_sq_wait))
wake_up(&ctx->sqo_sq_wait);
if (creds)
revert_creds(creds);
}
return ret;
}
static bool io_sqd_handle_event(struct io_sq_data *sqd)
{
bool did_sig = false;
struct ksignal ksig;
if (test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state) ||
signal_pending(current)) {
mutex_unlock(&sqd->lock);
if (signal_pending(current))
did_sig = get_signal(&ksig);
cond_resched();
mutex_lock(&sqd->lock);
}
return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
}
static int io_sq_thread(void *data)
{
struct io_sq_data *sqd = data;
struct io_ring_ctx *ctx;
unsigned long timeout = 0;
char buf[TASK_COMM_LEN];
DEFINE_WAIT(wait);
snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
set_task_comm(current, buf);
if (sqd->sq_cpu != -1)
set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu));
else
set_cpus_allowed_ptr(current, cpu_online_mask);
mutex_lock(&sqd->lock);
while (1) {
bool cap_entries, sqt_spin = false;
if (io_sqd_events_pending(sqd) || signal_pending(current)) {
if (io_sqd_handle_event(sqd))
break;
timeout = jiffies + sqd->sq_thread_idle;
}
cap_entries = !list_is_singular(&sqd->ctx_list);
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
int ret = __io_sq_thread(ctx, cap_entries);
if (!sqt_spin && (ret > 0 || !wq_list_empty(&ctx->iopoll_list)))
sqt_spin = true;
}
if (io_run_task_work())
sqt_spin = true;
if (sqt_spin || !time_after(jiffies, timeout)) {
if (sqt_spin)
timeout = jiffies + sqd->sq_thread_idle;
if (unlikely(need_resched())) {
mutex_unlock(&sqd->lock);
cond_resched();
mutex_lock(&sqd->lock);
}
continue;
}
prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
if (!io_sqd_events_pending(sqd) && !task_work_pending(current)) {
bool needs_sched = true;
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
atomic_or(IORING_SQ_NEED_WAKEUP,
&ctx->rings->sq_flags);
if ((ctx->flags & IORING_SETUP_IOPOLL) &&
!wq_list_empty(&ctx->iopoll_list)) {
needs_sched = false;
break;
}
/*
* Ensure the store of the wakeup flag is not
* reordered with the load of the SQ tail
*/
smp_mb__after_atomic();
if (io_sqring_entries(ctx)) {
needs_sched = false;
break;
}
}
if (needs_sched) {
mutex_unlock(&sqd->lock);
schedule();
mutex_lock(&sqd->lock);
}
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
atomic_andnot(IORING_SQ_NEED_WAKEUP,
&ctx->rings->sq_flags);
}
finish_wait(&sqd->wait, &wait);
timeout = jiffies + sqd->sq_thread_idle;
}
io_uring_cancel_generic(true, sqd);
sqd->thread = NULL;
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
atomic_or(IORING_SQ_NEED_WAKEUP, &ctx->rings->sq_flags);
io_run_task_work();
mutex_unlock(&sqd->lock);
complete(&sqd->exited);
do_exit(0);
}
void io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
{
DEFINE_WAIT(wait);
do {
if (!io_sqring_full(ctx))
break;
prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE);
if (!io_sqring_full(ctx))
break;
schedule();
} while (!signal_pending(current));
finish_wait(&ctx->sqo_sq_wait, &wait);
}
__cold int io_sq_offload_create(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
int ret;
/* Retain compatibility with failing for an invalid attach attempt */
if ((ctx->flags & (IORING_SETUP_ATTACH_WQ | IORING_SETUP_SQPOLL)) ==
IORING_SETUP_ATTACH_WQ) {
struct fd f;
f = fdget(p->wq_fd);
if (!f.file)
return -ENXIO;
if (!io_is_uring_fops(f.file)) {
fdput(f);
return -EINVAL;
}
fdput(f);
}
if (ctx->flags & IORING_SETUP_SQPOLL) {
struct task_struct *tsk;
struct io_sq_data *sqd;
bool attached;
ret = security_uring_sqpoll();
if (ret)
return ret;
sqd = io_get_sq_data(p, &attached);
if (IS_ERR(sqd)) {
ret = PTR_ERR(sqd);
goto err;
}
ctx->sq_creds = get_current_cred();
ctx->sq_data = sqd;
ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
if (!ctx->sq_thread_idle)
ctx->sq_thread_idle = HZ;
io_sq_thread_park(sqd);
list_add(&ctx->sqd_list, &sqd->ctx_list);
io_sqd_update_thread_idle(sqd);
/* don't attach to a dying SQPOLL thread, would be racy */
ret = (attached && !sqd->thread) ? -ENXIO : 0;
io_sq_thread_unpark(sqd);
if (ret < 0)
goto err;
if (attached)
return 0;
if (p->flags & IORING_SETUP_SQ_AFF) {
int cpu = p->sq_thread_cpu;
ret = -EINVAL;
if (cpu >= nr_cpu_ids || !cpu_online(cpu))
goto err_sqpoll;
sqd->sq_cpu = cpu;
} else {
sqd->sq_cpu = -1;
}
sqd->task_pid = current->pid;
sqd->task_tgid = current->tgid;
tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE);
if (IS_ERR(tsk)) {
ret = PTR_ERR(tsk);
goto err_sqpoll;
}
sqd->thread = tsk;
ret = io_uring_alloc_task_context(tsk, ctx);
wake_up_new_task(tsk);
if (ret)
goto err;
} else if (p->flags & IORING_SETUP_SQ_AFF) {
/* Can't have SQ_AFF without SQPOLL */
ret = -EINVAL;
goto err;
}
return 0;
err_sqpoll:
complete(&ctx->sq_data->exited);
err:
io_sq_thread_finish(ctx);
return ret;
}
__cold int io_sqpoll_wq_cpu_affinity(struct io_ring_ctx *ctx,
cpumask_var_t mask)
{
struct io_sq_data *sqd = ctx->sq_data;
int ret = -EINVAL;
if (sqd) {
io_sq_thread_park(sqd);
/* Don't set affinity for a dying thread */
if (sqd->thread)
ret = io_wq_cpu_affinity(sqd->thread->io_uring, mask);
io_sq_thread_unpark(sqd);
}
return ret;
}
| linux-master | io_uring/sqpoll.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/blk-mq.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/fsnotify.h>
#include <linux/poll.h>
#include <linux/nospec.h>
#include <linux/compat.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "opdef.h"
#include "kbuf.h"
#include "rsrc.h"
#include "rw.h"
struct io_rw {
/* NOTE: kiocb has the file as the first member, so don't do it here */
struct kiocb kiocb;
u64 addr;
u32 len;
rwf_t flags;
};
static inline bool io_file_supports_nowait(struct io_kiocb *req)
{
return req->flags & REQ_F_SUPPORT_NOWAIT;
}
#ifdef CONFIG_COMPAT
static int io_iov_compat_buffer_select_prep(struct io_rw *rw)
{
struct compat_iovec __user *uiov;
compat_ssize_t clen;
uiov = u64_to_user_ptr(rw->addr);
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(clen, &uiov->iov_len))
return -EFAULT;
if (clen < 0)
return -EINVAL;
rw->len = clen;
return 0;
}
#endif
static int io_iov_buffer_select_prep(struct io_kiocb *req)
{
struct iovec __user *uiov;
struct iovec iov;
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
if (rw->len != 1)
return -EINVAL;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return io_iov_compat_buffer_select_prep(rw);
#endif
uiov = u64_to_user_ptr(rw->addr);
if (copy_from_user(&iov, uiov, sizeof(*uiov)))
return -EFAULT;
rw->len = iov.iov_len;
return 0;
}
int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
unsigned ioprio;
int ret;
rw->kiocb.ki_pos = READ_ONCE(sqe->off);
/* used for fixed read/write too - just read unconditionally */
req->buf_index = READ_ONCE(sqe->buf_index);
if (req->opcode == IORING_OP_READ_FIXED ||
req->opcode == IORING_OP_WRITE_FIXED) {
struct io_ring_ctx *ctx = req->ctx;
u16 index;
if (unlikely(req->buf_index >= ctx->nr_user_bufs))
return -EFAULT;
index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
req->imu = ctx->user_bufs[index];
io_req_set_rsrc_node(req, ctx, 0);
}
ioprio = READ_ONCE(sqe->ioprio);
if (ioprio) {
ret = ioprio_check_cap(ioprio);
if (ret)
return ret;
rw->kiocb.ki_ioprio = ioprio;
} else {
rw->kiocb.ki_ioprio = get_current_ioprio();
}
rw->kiocb.dio_complete = NULL;
rw->addr = READ_ONCE(sqe->addr);
rw->len = READ_ONCE(sqe->len);
rw->flags = READ_ONCE(sqe->rw_flags);
/* Have to do this validation here, as this is in io_read() rw->len might
* have chanaged due to buffer selection
*/
if (req->opcode == IORING_OP_READV && req->flags & REQ_F_BUFFER_SELECT) {
ret = io_iov_buffer_select_prep(req);
if (ret)
return ret;
}
return 0;
}
void io_readv_writev_cleanup(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
kfree(io->free_iovec);
}
static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
{
switch (ret) {
case -EIOCBQUEUED:
break;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/*
* We can't just restart the syscall, since previously
* submitted sqes may already be in progress. Just fail this
* IO with EINTR.
*/
ret = -EINTR;
fallthrough;
default:
kiocb->ki_complete(kiocb, ret);
}
}
static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
if (rw->kiocb.ki_pos != -1)
return &rw->kiocb.ki_pos;
if (!(req->file->f_mode & FMODE_STREAM)) {
req->flags |= REQ_F_CUR_POS;
rw->kiocb.ki_pos = req->file->f_pos;
return &rw->kiocb.ki_pos;
}
rw->kiocb.ki_pos = 0;
return NULL;
}
static void io_req_task_queue_reissue(struct io_kiocb *req)
{
req->io_task_work.func = io_queue_iowq;
io_req_task_work_add(req);
}
#ifdef CONFIG_BLOCK
static bool io_resubmit_prep(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
if (!req_has_async_data(req))
return !io_req_prep_async(req);
iov_iter_restore(&io->s.iter, &io->s.iter_state);
return true;
}
static bool io_rw_should_reissue(struct io_kiocb *req)
{
umode_t mode = file_inode(req->file)->i_mode;
struct io_ring_ctx *ctx = req->ctx;
if (!S_ISBLK(mode) && !S_ISREG(mode))
return false;
if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
!(ctx->flags & IORING_SETUP_IOPOLL)))
return false;
/*
* If ref is dying, we might be running poll reap from the exit work.
* Don't attempt to reissue from that path, just let it fail with
* -EAGAIN.
*/
if (percpu_ref_is_dying(&ctx->refs))
return false;
/*
* Play it safe and assume not safe to re-import and reissue if we're
* not in the original thread group (or in task context).
*/
if (!same_thread_group(req->task, current) || !in_task())
return false;
return true;
}
#else
static bool io_resubmit_prep(struct io_kiocb *req)
{
return false;
}
static bool io_rw_should_reissue(struct io_kiocb *req)
{
return false;
}
#endif
static void io_req_end_write(struct io_kiocb *req)
{
if (req->flags & REQ_F_ISREG) {
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
kiocb_end_write(&rw->kiocb);
}
}
/*
* Trigger the notifications after having done some IO, and finish the write
* accounting, if any.
*/
static void io_req_io_end(struct io_kiocb *req)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
if (rw->kiocb.ki_flags & IOCB_WRITE) {
io_req_end_write(req);
fsnotify_modify(req->file);
} else {
fsnotify_access(req->file);
}
}
static bool __io_complete_rw_common(struct io_kiocb *req, long res)
{
if (unlikely(res != req->cqe.res)) {
if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
io_rw_should_reissue(req)) {
/*
* Reissue will start accounting again, finish the
* current cycle.
*/
io_req_io_end(req);
req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
return true;
}
req_set_fail(req);
req->cqe.res = res;
}
return false;
}
static inline int io_fixup_rw_res(struct io_kiocb *req, long res)
{
struct io_async_rw *io = req->async_data;
/* add previously done IO, if any */
if (req_has_async_data(req) && io->bytes_done > 0) {
if (res < 0)
res = io->bytes_done;
else
res += io->bytes_done;
}
return res;
}
void io_req_rw_complete(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
struct kiocb *kiocb = &rw->kiocb;
if ((kiocb->ki_flags & IOCB_DIO_CALLER_COMP) && kiocb->dio_complete) {
long res = kiocb->dio_complete(rw->kiocb.private);
io_req_set_res(req, io_fixup_rw_res(req, res), 0);
}
io_req_io_end(req);
if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED;
req->cqe.flags |= io_put_kbuf(req, issue_flags);
}
io_req_task_complete(req, ts);
}
static void io_complete_rw(struct kiocb *kiocb, long res)
{
struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
struct io_kiocb *req = cmd_to_io_kiocb(rw);
if (!kiocb->dio_complete || !(kiocb->ki_flags & IOCB_DIO_CALLER_COMP)) {
if (__io_complete_rw_common(req, res))
return;
io_req_set_res(req, io_fixup_rw_res(req, res), 0);
}
req->io_task_work.func = io_req_rw_complete;
__io_req_task_work_add(req, IOU_F_TWQ_LAZY_WAKE);
}
static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
{
struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
struct io_kiocb *req = cmd_to_io_kiocb(rw);
if (kiocb->ki_flags & IOCB_WRITE)
io_req_end_write(req);
if (unlikely(res != req->cqe.res)) {
if (res == -EAGAIN && io_rw_should_reissue(req)) {
req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
return;
}
req->cqe.res = res;
}
/* order with io_iopoll_complete() checking ->iopoll_completed */
smp_store_release(&req->iopoll_completed, 1);
}
static int kiocb_done(struct io_kiocb *req, ssize_t ret,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
unsigned final_ret = io_fixup_rw_res(req, ret);
if (req->flags & REQ_F_CUR_POS)
req->file->f_pos = rw->kiocb.ki_pos;
if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) {
if (!__io_complete_rw_common(req, ret)) {
/*
* Safe to call io_end from here as we're inline
* from the submission path.
*/
io_req_io_end(req);
io_req_set_res(req, final_ret,
io_put_kbuf(req, issue_flags));
return IOU_OK;
}
} else {
io_rw_done(&rw->kiocb, ret);
}
if (req->flags & REQ_F_REISSUE) {
req->flags &= ~REQ_F_REISSUE;
if (io_resubmit_prep(req))
io_req_task_queue_reissue(req);
else
io_req_task_queue_fail(req, final_ret);
}
return IOU_ISSUE_SKIP_COMPLETE;
}
static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
struct io_rw_state *s,
unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
struct iov_iter *iter = &s->iter;
u8 opcode = req->opcode;
struct iovec *iovec;
void __user *buf;
size_t sqe_len;
ssize_t ret;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len);
if (ret)
return ERR_PTR(ret);
return NULL;
}
buf = u64_to_user_ptr(rw->addr);
sqe_len = rw->len;
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE ||
(req->flags & REQ_F_BUFFER_SELECT)) {
if (io_do_buffer_select(req)) {
buf = io_buffer_select(req, &sqe_len, issue_flags);
if (!buf)
return ERR_PTR(-ENOBUFS);
rw->addr = (unsigned long) buf;
rw->len = sqe_len;
}
ret = import_ubuf(ddir, buf, sqe_len, iter);
if (ret)
return ERR_PTR(ret);
return NULL;
}
iovec = s->fast_iov;
ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
req->ctx->compat);
if (unlikely(ret < 0))
return ERR_PTR(ret);
return iovec;
}
static inline int io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct io_rw_state *s,
unsigned int issue_flags)
{
*iovec = __io_import_iovec(rw, req, s, issue_flags);
if (IS_ERR(*iovec))
return PTR_ERR(*iovec);
iov_iter_save_state(&s->iter, &s->iter_state);
return 0;
}
static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
{
return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
}
/*
* For files that don't have ->read_iter() and ->write_iter(), handle them
* by looping over ->read() or ->write() manually.
*/
static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
{
struct kiocb *kiocb = &rw->kiocb;
struct file *file = kiocb->ki_filp;
ssize_t ret = 0;
loff_t *ppos;
/*
* Don't support polled IO through this interface, and we can't
* support non-blocking either. For the latter, this just causes
* the kiocb to be handled from an async context.
*/
if (kiocb->ki_flags & IOCB_HIPRI)
return -EOPNOTSUPP;
if ((kiocb->ki_flags & IOCB_NOWAIT) &&
!(kiocb->ki_filp->f_flags & O_NONBLOCK))
return -EAGAIN;
ppos = io_kiocb_ppos(kiocb);
while (iov_iter_count(iter)) {
void __user *addr;
size_t len;
ssize_t nr;
if (iter_is_ubuf(iter)) {
addr = iter->ubuf + iter->iov_offset;
len = iov_iter_count(iter);
} else if (!iov_iter_is_bvec(iter)) {
addr = iter_iov_addr(iter);
len = iter_iov_len(iter);
} else {
addr = u64_to_user_ptr(rw->addr);
len = rw->len;
}
if (ddir == READ)
nr = file->f_op->read(file, addr, len, ppos);
else
nr = file->f_op->write(file, addr, len, ppos);
if (nr < 0) {
if (!ret)
ret = nr;
break;
}
ret += nr;
if (!iov_iter_is_bvec(iter)) {
iov_iter_advance(iter, nr);
} else {
rw->addr += nr;
rw->len -= nr;
if (!rw->len)
break;
}
if (nr != len)
break;
}
return ret;
}
static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
const struct iovec *fast_iov, struct iov_iter *iter)
{
struct io_async_rw *io = req->async_data;
memcpy(&io->s.iter, iter, sizeof(*iter));
io->free_iovec = iovec;
io->bytes_done = 0;
/* can only be fixed buffers, no need to do anything */
if (iov_iter_is_bvec(iter) || iter_is_ubuf(iter))
return;
if (!iovec) {
unsigned iov_off = 0;
io->s.iter.__iov = io->s.fast_iov;
if (iter->__iov != fast_iov) {
iov_off = iter_iov(iter) - fast_iov;
io->s.iter.__iov += iov_off;
}
if (io->s.fast_iov != fast_iov)
memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,
sizeof(struct iovec) * iter->nr_segs);
} else {
req->flags |= REQ_F_NEED_CLEANUP;
}
}
static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
struct io_rw_state *s, bool force)
{
if (!force && !io_cold_defs[req->opcode].prep_async)
return 0;
if (!req_has_async_data(req)) {
struct io_async_rw *iorw;
if (io_alloc_async_data(req)) {
kfree(iovec);
return -ENOMEM;
}
io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
iorw = req->async_data;
/* we've copied and mapped the iter, ensure state is saved */
iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
}
return 0;
}
static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
{
struct io_async_rw *iorw = req->async_data;
struct iovec *iov;
int ret;
/* submission path, ->uring_lock should already be taken */
ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
if (unlikely(ret < 0))
return ret;
iorw->bytes_done = 0;
iorw->free_iovec = iov;
if (iov)
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
int io_readv_prep_async(struct io_kiocb *req)
{
return io_rw_prep_async(req, ITER_DEST);
}
int io_writev_prep_async(struct io_kiocb *req)
{
return io_rw_prep_async(req, ITER_SOURCE);
}
/*
* This is our waitqueue callback handler, registered through __folio_lock_async()
* when we initially tried to do the IO with the iocb armed our waitqueue.
* This gets called when the page is unlocked, and we generally expect that to
* happen when the page IO is completed and the page is now uptodate. This will
* queue a task_work based retry of the operation, attempting to copy the data
* again. If the latter fails because the page was NOT uptodate, then we will
* do a thread based blocking retry of the operation. That's the unexpected
* slow path.
*/
static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
int sync, void *arg)
{
struct wait_page_queue *wpq;
struct io_kiocb *req = wait->private;
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
struct wait_page_key *key = arg;
wpq = container_of(wait, struct wait_page_queue, wait);
if (!wake_page_match(wpq, key))
return 0;
rw->kiocb.ki_flags &= ~IOCB_WAITQ;
list_del_init(&wait->entry);
io_req_task_queue(req);
return 1;
}
/*
* This controls whether a given IO request should be armed for async page
* based retry. If we return false here, the request is handed to the async
* worker threads for retry. If we're doing buffered reads on a regular file,
* we prepare a private wait_page_queue entry and retry the operation. This
* will either succeed because the page is now uptodate and unlocked, or it
* will register a callback when the page is unlocked at IO completion. Through
* that callback, io_uring uses task_work to setup a retry of the operation.
* That retry will attempt the buffered read again. The retry will generally
* succeed, or in rare cases where it fails, we then fall back to using the
* async worker threads for a blocking retry.
*/
static bool io_rw_should_retry(struct io_kiocb *req)
{
struct io_async_rw *io = req->async_data;
struct wait_page_queue *wait = &io->wpq;
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
struct kiocb *kiocb = &rw->kiocb;
/* never retry for NOWAIT, we just complete with -EAGAIN */
if (req->flags & REQ_F_NOWAIT)
return false;
/* Only for buffered IO */
if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
return false;
/*
* just use poll if we can, and don't attempt if the fs doesn't
* support callback based unlocks
*/
if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
return false;
wait->wait.func = io_async_buf_func;
wait->wait.private = req;
wait->wait.flags = 0;
INIT_LIST_HEAD(&wait->wait.entry);
kiocb->ki_flags |= IOCB_WAITQ;
kiocb->ki_flags &= ~IOCB_NOWAIT;
kiocb->ki_waitq = wait;
return true;
}
static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter)
{
struct file *file = rw->kiocb.ki_filp;
if (likely(file->f_op->read_iter))
return call_read_iter(file, &rw->kiocb, iter);
else if (file->f_op->read)
return loop_rw_iter(READ, rw, iter);
else
return -EINVAL;
}
static bool need_complete_io(struct io_kiocb *req)
{
return req->flags & REQ_F_ISREG ||
S_ISBLK(file_inode(req->file)->i_mode);
}
static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
struct kiocb *kiocb = &rw->kiocb;
struct io_ring_ctx *ctx = req->ctx;
struct file *file = req->file;
int ret;
if (unlikely(!file || !(file->f_mode & mode)))
return -EBADF;
if (!(req->flags & REQ_F_FIXED_FILE))
req->flags |= io_file_get_flags(file);
kiocb->ki_flags = file->f_iocb_flags;
ret = kiocb_set_rw_flags(kiocb, rw->flags);
if (unlikely(ret))
return ret;
kiocb->ki_flags |= IOCB_ALLOC_CACHE;
/*
* If the file is marked O_NONBLOCK, still allow retry for it if it
* supports async. Otherwise it's impossible to use O_NONBLOCK files
* reliably. If not, or it IOCB_NOWAIT is set, don't retry.
*/
if ((kiocb->ki_flags & IOCB_NOWAIT) ||
((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
req->flags |= REQ_F_NOWAIT;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
return -EOPNOTSUPP;
kiocb->private = NULL;
kiocb->ki_flags |= IOCB_HIPRI;
kiocb->ki_complete = io_complete_rw_iopoll;
req->iopoll_completed = 0;
} else {
if (kiocb->ki_flags & IOCB_HIPRI)
return -EINVAL;
kiocb->ki_complete = io_complete_rw;
}
return 0;
}
int io_read(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
struct io_rw_state __s, *s = &__s;
struct iovec *iovec;
struct kiocb *kiocb = &rw->kiocb;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
struct io_async_rw *io;
ssize_t ret, ret2;
loff_t *ppos;
if (!req_has_async_data(req)) {
ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
} else {
io = req->async_data;
s = &io->s;
/*
* Safe and required to re-import if we're using provided
* buffers, as we dropped the selected one before retry.
*/
if (io_do_buffer_select(req)) {
ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
}
/*
* We come here from an earlier attempt, restore our state to
* match in case it doesn't. It's cheap enough that we don't
* need to make this conditional.
*/
iov_iter_restore(&s->iter, &s->iter_state);
iovec = NULL;
}
ret = io_rw_init_file(req, FMODE_READ);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
req->cqe.res = iov_iter_count(&s->iter);
if (force_nonblock) {
/* If the file doesn't support async, just async punt */
if (unlikely(!io_file_supports_nowait(req))) {
ret = io_setup_async_rw(req, iovec, s, true);
return ret ?: -EAGAIN;
}
kiocb->ki_flags |= IOCB_NOWAIT;
} else {
/* Ensure we clear previously set non-block flag */
kiocb->ki_flags &= ~IOCB_NOWAIT;
}
ppos = io_kiocb_update_pos(req);
ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
ret = io_iter_do_read(rw, &s->iter);
if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
req->flags &= ~REQ_F_REISSUE;
/* if we can poll, just do that */
if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
return -EAGAIN;
/* IOPOLL retry should happen for io-wq threads */
if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
goto done;
/* no retry on NONBLOCK nor RWF_NOWAIT */
if (req->flags & REQ_F_NOWAIT)
goto done;
ret = 0;
} else if (ret == -EIOCBQUEUED) {
if (iovec)
kfree(iovec);
return IOU_ISSUE_SKIP_COMPLETE;
} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
(req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) {
/* read all, failed, already did sync or don't want to retry */
goto done;
}
/*
* Don't depend on the iter state matching what was consumed, or being
* untouched in case of error. Restore it and we'll advance it
* manually if we need to.
*/
iov_iter_restore(&s->iter, &s->iter_state);
ret2 = io_setup_async_rw(req, iovec, s, true);
iovec = NULL;
if (ret2) {
ret = ret > 0 ? ret : ret2;
goto done;
}
io = req->async_data;
s = &io->s;
/*
* Now use our persistent iterator and state, if we aren't already.
* We've restored and mapped the iter to match.
*/
do {
/*
* We end up here because of a partial read, either from
* above or inside this loop. Advance the iter by the bytes
* that were consumed.
*/
iov_iter_advance(&s->iter, ret);
if (!iov_iter_count(&s->iter))
break;
io->bytes_done += ret;
iov_iter_save_state(&s->iter, &s->iter_state);
/* if we can retry, do so with the callbacks armed */
if (!io_rw_should_retry(req)) {
kiocb->ki_flags &= ~IOCB_WAITQ;
return -EAGAIN;
}
req->cqe.res = iov_iter_count(&s->iter);
/*
* Now retry read with the IOCB_WAITQ parts set in the iocb. If
* we get -EIOCBQUEUED, then we'll get a notification when the
* desired page gets unlocked. We can also get a partial read
* here, and if we do, then just retry at the new offset.
*/
ret = io_iter_do_read(rw, &s->iter);
if (ret == -EIOCBQUEUED)
return IOU_ISSUE_SKIP_COMPLETE;
/* we got some bytes, but not all. retry. */
kiocb->ki_flags &= ~IOCB_WAITQ;
iov_iter_restore(&s->iter, &s->iter_state);
} while (ret > 0);
done:
/* it's faster to check here then delegate to kfree */
if (iovec)
kfree(iovec);
return kiocb_done(req, ret, issue_flags);
}
int io_write(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
struct io_rw_state __s, *s = &__s;
struct iovec *iovec;
struct kiocb *kiocb = &rw->kiocb;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
ssize_t ret, ret2;
loff_t *ppos;
if (!req_has_async_data(req)) {
ret = io_import_iovec(ITER_SOURCE, req, &iovec, s, issue_flags);
if (unlikely(ret < 0))
return ret;
} else {
struct io_async_rw *io = req->async_data;
s = &io->s;
iov_iter_restore(&s->iter, &s->iter_state);
iovec = NULL;
}
ret = io_rw_init_file(req, FMODE_WRITE);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
req->cqe.res = iov_iter_count(&s->iter);
if (force_nonblock) {
/* If the file doesn't support async, just async punt */
if (unlikely(!io_file_supports_nowait(req)))
goto copy_iov;
/* File path supports NOWAIT for non-direct_IO only for block devices. */
if (!(kiocb->ki_flags & IOCB_DIRECT) &&
!(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) &&
(req->flags & REQ_F_ISREG))
goto copy_iov;
kiocb->ki_flags |= IOCB_NOWAIT;
} else {
/* Ensure we clear previously set non-block flag */
kiocb->ki_flags &= ~IOCB_NOWAIT;
}
ppos = io_kiocb_update_pos(req);
ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
if (unlikely(ret)) {
kfree(iovec);
return ret;
}
if (req->flags & REQ_F_ISREG)
kiocb_start_write(kiocb);
kiocb->ki_flags |= IOCB_WRITE;
/*
* For non-polled IO, set IOCB_DIO_CALLER_COMP, stating that our handler
* groks deferring the completion to task context. This isn't
* necessary and useful for polled IO as that can always complete
* directly.
*/
if (!(kiocb->ki_flags & IOCB_HIPRI))
kiocb->ki_flags |= IOCB_DIO_CALLER_COMP;
if (likely(req->file->f_op->write_iter))
ret2 = call_write_iter(req->file, kiocb, &s->iter);
else if (req->file->f_op->write)
ret2 = loop_rw_iter(WRITE, rw, &s->iter);
else
ret2 = -EINVAL;
if (req->flags & REQ_F_REISSUE) {
req->flags &= ~REQ_F_REISSUE;
ret2 = -EAGAIN;
}
/*
* Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
* retry them without IOCB_NOWAIT.
*/
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
ret2 = -EAGAIN;
/* no retry on NONBLOCK nor RWF_NOWAIT */
if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
goto done;
if (!force_nonblock || ret2 != -EAGAIN) {
/* IOPOLL retry should happen for io-wq threads */
if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
goto copy_iov;
if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) {
struct io_async_rw *io;
trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2,
req->cqe.res, ret2);
/* This is a partial write. The file pos has already been
* updated, setup the async struct to complete the request
* in the worker. Also update bytes_done to account for
* the bytes already written.
*/
iov_iter_save_state(&s->iter, &s->iter_state);
ret = io_setup_async_rw(req, iovec, s, true);
io = req->async_data;
if (io)
io->bytes_done += ret2;
if (kiocb->ki_flags & IOCB_WRITE)
io_req_end_write(req);
return ret ? ret : -EAGAIN;
}
done:
ret = kiocb_done(req, ret2, issue_flags);
} else {
copy_iov:
iov_iter_restore(&s->iter, &s->iter_state);
ret = io_setup_async_rw(req, iovec, s, false);
if (!ret) {
if (kiocb->ki_flags & IOCB_WRITE)
io_req_end_write(req);
return -EAGAIN;
}
return ret;
}
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
kfree(iovec);
return ret;
}
void io_rw_fail(struct io_kiocb *req)
{
int res;
res = io_fixup_rw_res(req, req->cqe.res);
io_req_set_res(req, res, req->cqe.flags);
}
int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
{
struct io_wq_work_node *pos, *start, *prev;
unsigned int poll_flags = 0;
DEFINE_IO_COMP_BATCH(iob);
int nr_events = 0;
/*
* Only spin for completions if we don't have multiple devices hanging
* off our complete list.
*/
if (ctx->poll_multi_queue || force_nonspin)
poll_flags |= BLK_POLL_ONESHOT;
wq_list_for_each(pos, start, &ctx->iopoll_list) {
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
struct file *file = req->file;
int ret;
/*
* Move completed and retryable entries to our local lists.
* If we find a request that requires polling, break out
* and complete those lists first, if we have entries there.
*/
if (READ_ONCE(req->iopoll_completed))
break;
if (req->opcode == IORING_OP_URING_CMD) {
struct io_uring_cmd *ioucmd;
ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
ret = file->f_op->uring_cmd_iopoll(ioucmd, &iob,
poll_flags);
} else {
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
ret = file->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
}
if (unlikely(ret < 0))
return ret;
else if (ret)
poll_flags |= BLK_POLL_ONESHOT;
/* iopoll may have completed current req */
if (!rq_list_empty(iob.req_list) ||
READ_ONCE(req->iopoll_completed))
break;
}
if (!rq_list_empty(iob.req_list))
iob.complete(&iob);
else if (!pos)
return 0;
prev = start;
wq_list_for_each_resume(pos, prev) {
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
/* order with io_complete_rw_iopoll(), e.g. ->result updates */
if (!smp_load_acquire(&req->iopoll_completed))
break;
nr_events++;
req->cqe.flags = io_put_kbuf(req, 0);
}
if (unlikely(!nr_events))
return 0;
pos = start ? start->next : ctx->iopoll_list.first;
wq_list_cut(&ctx->iopoll_list, prev, start);
if (WARN_ON_ONCE(!wq_list_empty(&ctx->submit_state.compl_reqs)))
return 0;
ctx->submit_state.compl_reqs.first = pos;
__io_submit_flush_completions(ctx);
return nr_events;
}
| linux-master | io_uring/rw.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/super.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* super.c contains code to handle: - mount structures
* - super-block tables
* - filesystem drivers list
* - mount system call
* - umount system call
* - ustat system call
*
* GK 2/5/95 - Changed to support mounting the root fs via NFS
*
* Added kerneld support: Jacques Gelinas and Bjorn Ekwall
* Added change_root: Werner Almesberger & Hans Lermen, Feb '96
* Added options to /proc/mounts:
* Torbjörn Lindh ([email protected]), April 14, 1996.
* Added devfs support: Richard Gooch <[email protected]>, 13-JAN-1998
* Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
*/
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/writeback.h> /* for the emergency remount stuff */
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/backing-dev.h>
#include <linux/rculist_bl.h>
#include <linux/fscrypt.h>
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
#include <uapi/linux/mount.h>
#include "internal.h"
static int thaw_super_locked(struct super_block *sb, enum freeze_holder who);
static LIST_HEAD(super_blocks);
static DEFINE_SPINLOCK(sb_lock);
static char *sb_writers_name[SB_FREEZE_LEVELS] = {
"sb_writers",
"sb_pagefaults",
"sb_internal",
};
static inline void __super_lock(struct super_block *sb, bool excl)
{
if (excl)
down_write(&sb->s_umount);
else
down_read(&sb->s_umount);
}
static inline void super_unlock(struct super_block *sb, bool excl)
{
if (excl)
up_write(&sb->s_umount);
else
up_read(&sb->s_umount);
}
static inline void __super_lock_excl(struct super_block *sb)
{
__super_lock(sb, true);
}
static inline void super_unlock_excl(struct super_block *sb)
{
super_unlock(sb, true);
}
static inline void super_unlock_shared(struct super_block *sb)
{
super_unlock(sb, false);
}
static inline bool wait_born(struct super_block *sb)
{
unsigned int flags;
/*
* Pairs with smp_store_release() in super_wake() and ensures
* that we see SB_BORN or SB_DYING after we're woken.
*/
flags = smp_load_acquire(&sb->s_flags);
return flags & (SB_BORN | SB_DYING);
}
/**
* super_lock - wait for superblock to become ready and lock it
* @sb: superblock to wait for
* @excl: whether exclusive access is required
*
* If the superblock has neither passed through vfs_get_tree() or
* generic_shutdown_super() yet wait for it to happen. Either superblock
* creation will succeed and SB_BORN is set by vfs_get_tree() or we're
* woken and we'll see SB_DYING.
*
* The caller must have acquired a temporary reference on @sb->s_count.
*
* Return: This returns true if SB_BORN was set, false if SB_DYING was
* set. The function acquires s_umount and returns with it held.
*/
static __must_check bool super_lock(struct super_block *sb, bool excl)
{
lockdep_assert_not_held(&sb->s_umount);
relock:
__super_lock(sb, excl);
/*
* Has gone through generic_shutdown_super() in the meantime.
* @sb->s_root is NULL and @sb->s_active is 0. No one needs to
* grab a reference to this. Tell them so.
*/
if (sb->s_flags & SB_DYING)
return false;
/* Has called ->get_tree() successfully. */
if (sb->s_flags & SB_BORN)
return true;
super_unlock(sb, excl);
/* wait until the superblock is ready or dying */
wait_var_event(&sb->s_flags, wait_born(sb));
/*
* Neither SB_BORN nor SB_DYING are ever unset so we never loop.
* Just reacquire @sb->s_umount for the caller.
*/
goto relock;
}
/* wait and acquire read-side of @sb->s_umount */
static inline bool super_lock_shared(struct super_block *sb)
{
return super_lock(sb, false);
}
/* wait and acquire write-side of @sb->s_umount */
static inline bool super_lock_excl(struct super_block *sb)
{
return super_lock(sb, true);
}
/* wake waiters */
#define SUPER_WAKE_FLAGS (SB_BORN | SB_DYING | SB_DEAD)
static void super_wake(struct super_block *sb, unsigned int flag)
{
WARN_ON_ONCE((flag & ~SUPER_WAKE_FLAGS));
WARN_ON_ONCE(hweight32(flag & SUPER_WAKE_FLAGS) > 1);
/*
* Pairs with smp_load_acquire() in super_lock() to make sure
* all initializations in the superblock are seen by the user
* seeing SB_BORN sent.
*/
smp_store_release(&sb->s_flags, sb->s_flags | flag);
/*
* Pairs with the barrier in prepare_to_wait_event() to make sure
* ___wait_var_event() either sees SB_BORN set or
* waitqueue_active() check in wake_up_var() sees the waiter.
*/
smp_mb();
wake_up_var(&sb->s_flags);
}
/*
* One thing we have to be careful of with a per-sb shrinker is that we don't
* drop the last active reference to the superblock from within the shrinker.
* If that happens we could trigger unregistering the shrinker from within the
* shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we
* take a passive reference to the superblock to avoid this from occurring.
*/
static unsigned long super_cache_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
struct super_block *sb;
long fs_objects = 0;
long total_objects;
long freed = 0;
long dentries;
long inodes;
sb = container_of(shrink, struct super_block, s_shrink);
/*
* Deadlock avoidance. We may hold various FS locks, and we don't want
* to recurse into the FS that called us in clear_inode() and friends..
*/
if (!(sc->gfp_mask & __GFP_FS))
return SHRINK_STOP;
if (!super_trylock_shared(sb))
return SHRINK_STOP;
if (sb->s_op->nr_cached_objects)
fs_objects = sb->s_op->nr_cached_objects(sb, sc);
inodes = list_lru_shrink_count(&sb->s_inode_lru, sc);
dentries = list_lru_shrink_count(&sb->s_dentry_lru, sc);
total_objects = dentries + inodes + fs_objects + 1;
if (!total_objects)
total_objects = 1;
/* proportion the scan between the caches */
dentries = mult_frac(sc->nr_to_scan, dentries, total_objects);
inodes = mult_frac(sc->nr_to_scan, inodes, total_objects);
fs_objects = mult_frac(sc->nr_to_scan, fs_objects, total_objects);
/*
* prune the dcache first as the icache is pinned by it, then
* prune the icache, followed by the filesystem specific caches
*
* Ensure that we always scan at least one object - memcg kmem
* accounting uses this to fully empty the caches.
*/
sc->nr_to_scan = dentries + 1;
freed = prune_dcache_sb(sb, sc);
sc->nr_to_scan = inodes + 1;
freed += prune_icache_sb(sb, sc);
if (fs_objects) {
sc->nr_to_scan = fs_objects + 1;
freed += sb->s_op->free_cached_objects(sb, sc);
}
super_unlock_shared(sb);
return freed;
}
static unsigned long super_cache_count(struct shrinker *shrink,
struct shrink_control *sc)
{
struct super_block *sb;
long total_objects = 0;
sb = container_of(shrink, struct super_block, s_shrink);
/*
* We don't call super_trylock_shared() here as it is a scalability
* bottleneck, so we're exposed to partial setup state. The shrinker
* rwsem does not protect filesystem operations backing
* list_lru_shrink_count() or s_op->nr_cached_objects(). Counts can
* change between super_cache_count and super_cache_scan, so we really
* don't need locks here.
*
* However, if we are currently mounting the superblock, the underlying
* filesystem might be in a state of partial construction and hence it
* is dangerous to access it. super_trylock_shared() uses a SB_BORN check
* to avoid this situation, so do the same here. The memory barrier is
* matched with the one in mount_fs() as we don't hold locks here.
*/
if (!(sb->s_flags & SB_BORN))
return 0;
smp_rmb();
if (sb->s_op && sb->s_op->nr_cached_objects)
total_objects = sb->s_op->nr_cached_objects(sb, sc);
total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc);
total_objects += list_lru_shrink_count(&sb->s_inode_lru, sc);
if (!total_objects)
return SHRINK_EMPTY;
total_objects = vfs_pressure_ratio(total_objects);
return total_objects;
}
static void destroy_super_work(struct work_struct *work)
{
struct super_block *s = container_of(work, struct super_block,
destroy_work);
int i;
for (i = 0; i < SB_FREEZE_LEVELS; i++)
percpu_free_rwsem(&s->s_writers.rw_sem[i]);
kfree(s);
}
static void destroy_super_rcu(struct rcu_head *head)
{
struct super_block *s = container_of(head, struct super_block, rcu);
INIT_WORK(&s->destroy_work, destroy_super_work);
schedule_work(&s->destroy_work);
}
/* Free a superblock that has never been seen by anyone */
static void destroy_unused_super(struct super_block *s)
{
if (!s)
return;
super_unlock_excl(s);
list_lru_destroy(&s->s_dentry_lru);
list_lru_destroy(&s->s_inode_lru);
security_sb_free(s);
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
free_prealloced_shrinker(&s->s_shrink);
/* no delays needed */
destroy_super_work(&s->destroy_work);
}
/**
* alloc_super - create new superblock
* @type: filesystem type superblock should belong to
* @flags: the mount flags
* @user_ns: User namespace for the super_block
*
* Allocates and initializes a new &struct super_block. alloc_super()
* returns a pointer new superblock or %NULL if allocation had failed.
*/
static struct super_block *alloc_super(struct file_system_type *type, int flags,
struct user_namespace *user_ns)
{
struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
static const struct super_operations default_op;
int i;
if (!s)
return NULL;
INIT_LIST_HEAD(&s->s_mounts);
s->s_user_ns = get_user_ns(user_ns);
init_rwsem(&s->s_umount);
lockdep_set_class(&s->s_umount, &type->s_umount_key);
/*
* sget() can have s_umount recursion.
*
* When it cannot find a suitable sb, it allocates a new
* one (this one), and tries again to find a suitable old
* one.
*
* In case that succeeds, it will acquire the s_umount
* lock of the old one. Since these are clearly distrinct
* locks, and this object isn't exposed yet, there's no
* risk of deadlocks.
*
* Annotate this by putting this lock in a different
* subclass.
*/
down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
if (security_sb_alloc(s))
goto fail;
for (i = 0; i < SB_FREEZE_LEVELS; i++) {
if (__percpu_init_rwsem(&s->s_writers.rw_sem[i],
sb_writers_name[i],
&type->s_writers_key[i]))
goto fail;
}
s->s_bdi = &noop_backing_dev_info;
s->s_flags = flags;
if (s->s_user_ns != &init_user_ns)
s->s_iflags |= SB_I_NODEV;
INIT_HLIST_NODE(&s->s_instances);
INIT_HLIST_BL_HEAD(&s->s_roots);
mutex_init(&s->s_sync_lock);
INIT_LIST_HEAD(&s->s_inodes);
spin_lock_init(&s->s_inode_list_lock);
INIT_LIST_HEAD(&s->s_inodes_wb);
spin_lock_init(&s->s_inode_wblist_lock);
s->s_count = 1;
atomic_set(&s->s_active, 1);
mutex_init(&s->s_vfs_rename_mutex);
lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
init_rwsem(&s->s_dquot.dqio_sem);
s->s_maxbytes = MAX_NON_LFS;
s->s_op = &default_op;
s->s_time_gran = 1000000000;
s->s_time_min = TIME64_MIN;
s->s_time_max = TIME64_MAX;
s->s_shrink.seeks = DEFAULT_SEEKS;
s->s_shrink.scan_objects = super_cache_scan;
s->s_shrink.count_objects = super_cache_count;
s->s_shrink.batch = 1024;
s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE;
if (prealloc_shrinker(&s->s_shrink, "sb-%s", type->name))
goto fail;
if (list_lru_init_memcg(&s->s_dentry_lru, &s->s_shrink))
goto fail;
if (list_lru_init_memcg(&s->s_inode_lru, &s->s_shrink))
goto fail;
return s;
fail:
destroy_unused_super(s);
return NULL;
}
/* Superblock refcounting */
/*
* Drop a superblock's refcount. The caller must hold sb_lock.
*/
static void __put_super(struct super_block *s)
{
if (!--s->s_count) {
list_del_init(&s->s_list);
WARN_ON(s->s_dentry_lru.node);
WARN_ON(s->s_inode_lru.node);
WARN_ON(!list_empty(&s->s_mounts));
security_sb_free(s);
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
call_rcu(&s->rcu, destroy_super_rcu);
}
}
/**
* put_super - drop a temporary reference to superblock
* @sb: superblock in question
*
* Drops a temporary reference, frees superblock if there's no
* references left.
*/
void put_super(struct super_block *sb)
{
spin_lock(&sb_lock);
__put_super(sb);
spin_unlock(&sb_lock);
}
static void kill_super_notify(struct super_block *sb)
{
lockdep_assert_not_held(&sb->s_umount);
/* already notified earlier */
if (sb->s_flags & SB_DEAD)
return;
/*
* Remove it from @fs_supers so it isn't found by new
* sget{_fc}() walkers anymore. Any concurrent mounter still
* managing to grab a temporary reference is guaranteed to
* already see SB_DYING and will wait until we notify them about
* SB_DEAD.
*/
spin_lock(&sb_lock);
hlist_del_init(&sb->s_instances);
spin_unlock(&sb_lock);
/*
* Let concurrent mounts know that this thing is really dead.
* We don't need @sb->s_umount here as every concurrent caller
* will see SB_DYING and either discard the superblock or wait
* for SB_DEAD.
*/
super_wake(sb, SB_DEAD);
}
/**
* deactivate_locked_super - drop an active reference to superblock
* @s: superblock to deactivate
*
* Drops an active reference to superblock, converting it into a temporary
* one if there is no other active references left. In that case we
* tell fs driver to shut it down and drop the temporary reference we
* had just acquired.
*
* Caller holds exclusive lock on superblock; that lock is released.
*/
void deactivate_locked_super(struct super_block *s)
{
struct file_system_type *fs = s->s_type;
if (atomic_dec_and_test(&s->s_active)) {
unregister_shrinker(&s->s_shrink);
fs->kill_sb(s);
kill_super_notify(s);
/*
* Since list_lru_destroy() may sleep, we cannot call it from
* put_super(), where we hold the sb_lock. Therefore we destroy
* the lru lists right now.
*/
list_lru_destroy(&s->s_dentry_lru);
list_lru_destroy(&s->s_inode_lru);
put_filesystem(fs);
put_super(s);
} else {
super_unlock_excl(s);
}
}
EXPORT_SYMBOL(deactivate_locked_super);
/**
* deactivate_super - drop an active reference to superblock
* @s: superblock to deactivate
*
* Variant of deactivate_locked_super(), except that superblock is *not*
* locked by caller. If we are going to drop the final active reference,
* lock will be acquired prior to that.
*/
void deactivate_super(struct super_block *s)
{
if (!atomic_add_unless(&s->s_active, -1, 1)) {
__super_lock_excl(s);
deactivate_locked_super(s);
}
}
EXPORT_SYMBOL(deactivate_super);
/**
* grab_super - acquire an active reference
* @s: reference we are trying to make active
*
* Tries to acquire an active reference. grab_super() is used when we
* had just found a superblock in super_blocks or fs_type->fs_supers
* and want to turn it into a full-blown active reference. grab_super()
* is called with sb_lock held and drops it. Returns 1 in case of
* success, 0 if we had failed (superblock contents was already dead or
* dying when grab_super() had been called). Note that this is only
* called for superblocks not in rundown mode (== ones still on ->fs_supers
* of their type), so increment of ->s_count is OK here.
*/
static int grab_super(struct super_block *s) __releases(sb_lock)
{
bool born;
s->s_count++;
spin_unlock(&sb_lock);
born = super_lock_excl(s);
if (born && atomic_inc_not_zero(&s->s_active)) {
put_super(s);
return 1;
}
super_unlock_excl(s);
put_super(s);
return 0;
}
static inline bool wait_dead(struct super_block *sb)
{
unsigned int flags;
/*
* Pairs with memory barrier in super_wake() and ensures
* that we see SB_DEAD after we're woken.
*/
flags = smp_load_acquire(&sb->s_flags);
return flags & SB_DEAD;
}
/**
* grab_super_dead - acquire an active reference to a superblock
* @sb: superblock to acquire
*
* Acquire a temporary reference on a superblock and try to trade it for
* an active reference. This is used in sget{_fc}() to wait for a
* superblock to either become SB_BORN or for it to pass through
* sb->kill() and be marked as SB_DEAD.
*
* Return: This returns true if an active reference could be acquired,
* false if not.
*/
static bool grab_super_dead(struct super_block *sb)
{
sb->s_count++;
if (grab_super(sb)) {
put_super(sb);
lockdep_assert_held(&sb->s_umount);
return true;
}
wait_var_event(&sb->s_flags, wait_dead(sb));
lockdep_assert_not_held(&sb->s_umount);
put_super(sb);
return false;
}
/*
* super_trylock_shared - try to grab ->s_umount shared
* @sb: reference we are trying to grab
*
* Try to prevent fs shutdown. This is used in places where we
* cannot take an active reference but we need to ensure that the
* filesystem is not shut down while we are working on it. It returns
* false if we cannot acquire s_umount or if we lose the race and
* filesystem already got into shutdown, and returns true with the s_umount
* lock held in read mode in case of success. On successful return,
* the caller must drop the s_umount lock when done.
*
* Note that unlike get_super() et.al. this one does *not* bump ->s_count.
* The reason why it's safe is that we are OK with doing trylock instead
* of down_read(). There's a couple of places that are OK with that, but
* it's very much not a general-purpose interface.
*/
bool super_trylock_shared(struct super_block *sb)
{
if (down_read_trylock(&sb->s_umount)) {
if (!(sb->s_flags & SB_DYING) && sb->s_root &&
(sb->s_flags & SB_BORN))
return true;
super_unlock_shared(sb);
}
return false;
}
/**
* retire_super - prevents superblock from being reused
* @sb: superblock to retire
*
* The function marks superblock to be ignored in superblock test, which
* prevents it from being reused for any new mounts. If the superblock has
* a private bdi, it also unregisters it, but doesn't reduce the refcount
* of the superblock to prevent potential races. The refcount is reduced
* by generic_shutdown_super(). The function can not be called
* concurrently with generic_shutdown_super(). It is safe to call the
* function multiple times, subsequent calls have no effect.
*
* The marker will affect the re-use only for block-device-based
* superblocks. Other superblocks will still get marked if this function
* is used, but that will not affect their reusability.
*/
void retire_super(struct super_block *sb)
{
WARN_ON(!sb->s_bdev);
__super_lock_excl(sb);
if (sb->s_iflags & SB_I_PERSB_BDI) {
bdi_unregister(sb->s_bdi);
sb->s_iflags &= ~SB_I_PERSB_BDI;
}
sb->s_iflags |= SB_I_RETIRED;
super_unlock_excl(sb);
}
EXPORT_SYMBOL(retire_super);
/**
* generic_shutdown_super - common helper for ->kill_sb()
* @sb: superblock to kill
*
* generic_shutdown_super() does all fs-independent work on superblock
* shutdown. Typical ->kill_sb() should pick all fs-specific objects
* that need destruction out of superblock, call generic_shutdown_super()
* and release aforementioned objects. Note: dentries and inodes _are_
* taken care of and do not need specific handling.
*
* Upon calling this function, the filesystem may no longer alter or
* rearrange the set of dentries belonging to this super_block, nor may it
* change the attachments of dentries to inodes.
*/
void generic_shutdown_super(struct super_block *sb)
{
const struct super_operations *sop = sb->s_op;
if (sb->s_root) {
shrink_dcache_for_umount(sb);
sync_filesystem(sb);
sb->s_flags &= ~SB_ACTIVE;
cgroup_writeback_umount();
/* Evict all inodes with zero refcount. */
evict_inodes(sb);
/*
* Clean up and evict any inodes that still have references due
* to fsnotify or the security policy.
*/
fsnotify_sb_delete(sb);
security_sb_delete(sb);
/*
* Now that all potentially-encrypted inodes have been evicted,
* the fscrypt keyring can be destroyed.
*/
fscrypt_destroy_keyring(sb);
if (sb->s_dio_done_wq) {
destroy_workqueue(sb->s_dio_done_wq);
sb->s_dio_done_wq = NULL;
}
if (sop->put_super)
sop->put_super(sb);
if (CHECK_DATA_CORRUPTION(!list_empty(&sb->s_inodes),
"VFS: Busy inodes after unmount of %s (%s)",
sb->s_id, sb->s_type->name)) {
/*
* Adding a proper bailout path here would be hard, but
* we can at least make it more likely that a later
* iput_final() or such crashes cleanly.
*/
struct inode *inode;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
inode->i_op = VFS_PTR_POISON;
inode->i_sb = VFS_PTR_POISON;
inode->i_mapping = VFS_PTR_POISON;
}
spin_unlock(&sb->s_inode_list_lock);
}
}
/*
* Broadcast to everyone that grabbed a temporary reference to this
* superblock before we removed it from @fs_supers that the superblock
* is dying. Every walker of @fs_supers outside of sget{_fc}() will now
* discard this superblock and treat it as dead.
*
* We leave the superblock on @fs_supers so it can be found by
* sget{_fc}() until we passed sb->kill_sb().
*/
super_wake(sb, SB_DYING);
super_unlock_excl(sb);
if (sb->s_bdi != &noop_backing_dev_info) {
if (sb->s_iflags & SB_I_PERSB_BDI)
bdi_unregister(sb->s_bdi);
bdi_put(sb->s_bdi);
sb->s_bdi = &noop_backing_dev_info;
}
}
EXPORT_SYMBOL(generic_shutdown_super);
bool mount_capable(struct fs_context *fc)
{
if (!(fc->fs_type->fs_flags & FS_USERNS_MOUNT))
return capable(CAP_SYS_ADMIN);
else
return ns_capable(fc->user_ns, CAP_SYS_ADMIN);
}
/**
* sget_fc - Find or create a superblock
* @fc: Filesystem context.
* @test: Comparison callback
* @set: Setup callback
*
* Create a new superblock or find an existing one.
*
* The @test callback is used to find a matching existing superblock.
* Whether or not the requested parameters in @fc are taken into account
* is specific to the @test callback that is used. They may even be
* completely ignored.
*
* If an extant superblock is matched, it will be returned unless:
*
* (1) the namespace the filesystem context @fc and the extant
* superblock's namespace differ
*
* (2) the filesystem context @fc has requested that reusing an extant
* superblock is not allowed
*
* In both cases EBUSY will be returned.
*
* If no match is made, a new superblock will be allocated and basic
* initialisation will be performed (s_type, s_fs_info and s_id will be
* set and the @set callback will be invoked), the superblock will be
* published and it will be returned in a partially constructed state
* with SB_BORN and SB_ACTIVE as yet unset.
*
* Return: On success, an extant or newly created superblock is
* returned. On failure an error pointer is returned.
*/
struct super_block *sget_fc(struct fs_context *fc,
int (*test)(struct super_block *, struct fs_context *),
int (*set)(struct super_block *, struct fs_context *))
{
struct super_block *s = NULL;
struct super_block *old;
struct user_namespace *user_ns = fc->global ? &init_user_ns : fc->user_ns;
int err;
retry:
spin_lock(&sb_lock);
if (test) {
hlist_for_each_entry(old, &fc->fs_type->fs_supers, s_instances) {
if (test(old, fc))
goto share_extant_sb;
}
}
if (!s) {
spin_unlock(&sb_lock);
s = alloc_super(fc->fs_type, fc->sb_flags, user_ns);
if (!s)
return ERR_PTR(-ENOMEM);
goto retry;
}
s->s_fs_info = fc->s_fs_info;
err = set(s, fc);
if (err) {
s->s_fs_info = NULL;
spin_unlock(&sb_lock);
destroy_unused_super(s);
return ERR_PTR(err);
}
fc->s_fs_info = NULL;
s->s_type = fc->fs_type;
s->s_iflags |= fc->s_iflags;
strscpy(s->s_id, s->s_type->name, sizeof(s->s_id));
/*
* Make the superblock visible on @super_blocks and @fs_supers.
* It's in a nascent state and users should wait on SB_BORN or
* SB_DYING to be set.
*/
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &s->s_type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(s->s_type);
register_shrinker_prepared(&s->s_shrink);
return s;
share_extant_sb:
if (user_ns != old->s_user_ns || fc->exclusive) {
spin_unlock(&sb_lock);
destroy_unused_super(s);
if (fc->exclusive)
warnfc(fc, "reusing existing filesystem not allowed");
else
warnfc(fc, "reusing existing filesystem in another namespace not allowed");
return ERR_PTR(-EBUSY);
}
if (!grab_super_dead(old))
goto retry;
destroy_unused_super(s);
return old;
}
EXPORT_SYMBOL(sget_fc);
/**
* sget - find or create a superblock
* @type: filesystem type superblock should belong to
* @test: comparison callback
* @set: setup callback
* @flags: mount flags
* @data: argument to each of them
*/
struct super_block *sget(struct file_system_type *type,
int (*test)(struct super_block *,void *),
int (*set)(struct super_block *,void *),
int flags,
void *data)
{
struct user_namespace *user_ns = current_user_ns();
struct super_block *s = NULL;
struct super_block *old;
int err;
/* We don't yet pass the user namespace of the parent
* mount through to here so always use &init_user_ns
* until that changes.
*/
if (flags & SB_SUBMOUNT)
user_ns = &init_user_ns;
retry:
spin_lock(&sb_lock);
if (test) {
hlist_for_each_entry(old, &type->fs_supers, s_instances) {
if (!test(old, data))
continue;
if (user_ns != old->s_user_ns) {
spin_unlock(&sb_lock);
destroy_unused_super(s);
return ERR_PTR(-EBUSY);
}
if (!grab_super_dead(old))
goto retry;
destroy_unused_super(s);
return old;
}
}
if (!s) {
spin_unlock(&sb_lock);
s = alloc_super(type, (flags & ~SB_SUBMOUNT), user_ns);
if (!s)
return ERR_PTR(-ENOMEM);
goto retry;
}
err = set(s, data);
if (err) {
spin_unlock(&sb_lock);
destroy_unused_super(s);
return ERR_PTR(err);
}
s->s_type = type;
strscpy(s->s_id, type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(type);
register_shrinker_prepared(&s->s_shrink);
return s;
}
EXPORT_SYMBOL(sget);
void drop_super(struct super_block *sb)
{
super_unlock_shared(sb);
put_super(sb);
}
EXPORT_SYMBOL(drop_super);
void drop_super_exclusive(struct super_block *sb)
{
super_unlock_excl(sb);
put_super(sb);
}
EXPORT_SYMBOL(drop_super_exclusive);
static void __iterate_supers(void (*f)(struct super_block *))
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
/* Pairs with memory marrier in super_wake(). */
if (smp_load_acquire(&sb->s_flags) & SB_DYING)
continue;
sb->s_count++;
spin_unlock(&sb_lock);
f(sb);
spin_lock(&sb_lock);
if (p)
__put_super(p);
p = sb;
}
if (p)
__put_super(p);
spin_unlock(&sb_lock);
}
/**
* iterate_supers - call function for all active superblocks
* @f: function to call
* @arg: argument to pass to it
*
* Scans the superblock list and calls given function, passing it
* locked superblock and given argument.
*/
void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
bool born;
sb->s_count++;
spin_unlock(&sb_lock);
born = super_lock_shared(sb);
if (born && sb->s_root)
f(sb, arg);
super_unlock_shared(sb);
spin_lock(&sb_lock);
if (p)
__put_super(p);
p = sb;
}
if (p)
__put_super(p);
spin_unlock(&sb_lock);
}
/**
* iterate_supers_type - call function for superblocks of given type
* @type: fs type
* @f: function to call
* @arg: argument to pass to it
*
* Scans the superblock list and calls given function, passing it
* locked superblock and given argument.
*/
void iterate_supers_type(struct file_system_type *type,
void (*f)(struct super_block *, void *), void *arg)
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
hlist_for_each_entry(sb, &type->fs_supers, s_instances) {
bool born;
sb->s_count++;
spin_unlock(&sb_lock);
born = super_lock_shared(sb);
if (born && sb->s_root)
f(sb, arg);
super_unlock_shared(sb);
spin_lock(&sb_lock);
if (p)
__put_super(p);
p = sb;
}
if (p)
__put_super(p);
spin_unlock(&sb_lock);
}
EXPORT_SYMBOL(iterate_supers_type);
/**
* get_active_super - get an active reference to the superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. Returns the superblock with an active
* reference or %NULL if none was found.
*/
struct super_block *get_active_super(struct block_device *bdev)
{
struct super_block *sb;
if (!bdev)
return NULL;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (sb->s_bdev == bdev) {
if (!grab_super(sb))
return NULL;
super_unlock_excl(sb);
return sb;
}
}
spin_unlock(&sb_lock);
return NULL;
}
struct super_block *user_get_super(dev_t dev, bool excl)
{
struct super_block *sb;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (sb->s_dev == dev) {
bool born;
sb->s_count++;
spin_unlock(&sb_lock);
/* still alive? */
born = super_lock(sb, excl);
if (born && sb->s_root)
return sb;
super_unlock(sb, excl);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);
break;
}
}
spin_unlock(&sb_lock);
return NULL;
}
/**
* reconfigure_super - asks filesystem to change superblock parameters
* @fc: The superblock and configuration
*
* Alters the configuration parameters of a live superblock.
*/
int reconfigure_super(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
int retval;
bool remount_ro = false;
bool remount_rw = false;
bool force = fc->sb_flags & SB_FORCE;
if (fc->sb_flags_mask & ~MS_RMT_MASK)
return -EINVAL;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
retval = security_sb_remount(sb, fc->security);
if (retval)
return retval;
if (fc->sb_flags_mask & SB_RDONLY) {
#ifdef CONFIG_BLOCK
if (!(fc->sb_flags & SB_RDONLY) && sb->s_bdev &&
bdev_read_only(sb->s_bdev))
return -EACCES;
#endif
remount_rw = !(fc->sb_flags & SB_RDONLY) && sb_rdonly(sb);
remount_ro = (fc->sb_flags & SB_RDONLY) && !sb_rdonly(sb);
}
if (remount_ro) {
if (!hlist_empty(&sb->s_pins)) {
super_unlock_excl(sb);
group_pin_kill(&sb->s_pins);
__super_lock_excl(sb);
if (!sb->s_root)
return 0;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
remount_ro = !sb_rdonly(sb);
}
}
shrink_dcache_sb(sb);
/* If we are reconfiguring to RDONLY and current sb is read/write,
* make sure there are no files open for writing.
*/
if (remount_ro) {
if (force) {
sb_start_ro_state_change(sb);
} else {
retval = sb_prepare_remount_readonly(sb);
if (retval)
return retval;
}
} else if (remount_rw) {
/*
* Protect filesystem's reconfigure code from writes from
* userspace until reconfigure finishes.
*/
sb_start_ro_state_change(sb);
}
if (fc->ops->reconfigure) {
retval = fc->ops->reconfigure(fc);
if (retval) {
if (!force)
goto cancel_readonly;
/* If forced remount, go ahead despite any errors */
WARN(1, "forced remount of a %s fs returned %i\n",
sb->s_type->name, retval);
}
}
WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) |
(fc->sb_flags & fc->sb_flags_mask)));
sb_end_ro_state_change(sb);
/*
* Some filesystems modify their metadata via some other path than the
* bdev buffer cache (eg. use a private mapping, or directories in
* pagecache, etc). Also file data modifications go via their own
* mappings. So If we try to mount readonly then copy the filesystem
* from bdev, we could get stale data, so invalidate it to give a best
* effort at coherency.
*/
if (remount_ro && sb->s_bdev)
invalidate_bdev(sb->s_bdev);
return 0;
cancel_readonly:
sb_end_ro_state_change(sb);
return retval;
}
static void do_emergency_remount_callback(struct super_block *sb)
{
bool born = super_lock_excl(sb);
if (born && sb->s_root && sb->s_bdev && !sb_rdonly(sb)) {
struct fs_context *fc;
fc = fs_context_for_reconfigure(sb->s_root,
SB_RDONLY | SB_FORCE, SB_RDONLY);
if (!IS_ERR(fc)) {
if (parse_monolithic_mount_data(fc, NULL) == 0)
(void)reconfigure_super(fc);
put_fs_context(fc);
}
}
super_unlock_excl(sb);
}
static void do_emergency_remount(struct work_struct *work)
{
__iterate_supers(do_emergency_remount_callback);
kfree(work);
printk("Emergency Remount complete\n");
}
void emergency_remount(void)
{
struct work_struct *work;
work = kmalloc(sizeof(*work), GFP_ATOMIC);
if (work) {
INIT_WORK(work, do_emergency_remount);
schedule_work(work);
}
}
static void do_thaw_all_callback(struct super_block *sb)
{
bool born = super_lock_excl(sb);
if (born && sb->s_root) {
if (IS_ENABLED(CONFIG_BLOCK))
while (sb->s_bdev && !thaw_bdev(sb->s_bdev))
pr_warn("Emergency Thaw on %pg\n", sb->s_bdev);
thaw_super_locked(sb, FREEZE_HOLDER_USERSPACE);
} else {
super_unlock_excl(sb);
}
}
static void do_thaw_all(struct work_struct *work)
{
__iterate_supers(do_thaw_all_callback);
kfree(work);
printk(KERN_WARNING "Emergency Thaw complete\n");
}
/**
* emergency_thaw_all -- forcibly thaw every frozen filesystem
*
* Used for emergency unfreeze of all filesystems via SysRq
*/
void emergency_thaw_all(void)
{
struct work_struct *work;
work = kmalloc(sizeof(*work), GFP_ATOMIC);
if (work) {
INIT_WORK(work, do_thaw_all);
schedule_work(work);
}
}
static DEFINE_IDA(unnamed_dev_ida);
/**
* get_anon_bdev - Allocate a block device for filesystems which don't have one.
* @p: Pointer to a dev_t.
*
* Filesystems which don't use real block devices can call this function
* to allocate a virtual block device.
*
* Context: Any context. Frequently called while holding sb_lock.
* Return: 0 on success, -EMFILE if there are no anonymous bdevs left
* or -ENOMEM if memory allocation failed.
*/
int get_anon_bdev(dev_t *p)
{
int dev;
/*
* Many userspace utilities consider an FSID of 0 invalid.
* Always return at least 1 from get_anon_bdev.
*/
dev = ida_alloc_range(&unnamed_dev_ida, 1, (1 << MINORBITS) - 1,
GFP_ATOMIC);
if (dev == -ENOSPC)
dev = -EMFILE;
if (dev < 0)
return dev;
*p = MKDEV(0, dev);
return 0;
}
EXPORT_SYMBOL(get_anon_bdev);
void free_anon_bdev(dev_t dev)
{
ida_free(&unnamed_dev_ida, MINOR(dev));
}
EXPORT_SYMBOL(free_anon_bdev);
int set_anon_super(struct super_block *s, void *data)
{
return get_anon_bdev(&s->s_dev);
}
EXPORT_SYMBOL(set_anon_super);
void kill_anon_super(struct super_block *sb)
{
dev_t dev = sb->s_dev;
generic_shutdown_super(sb);
kill_super_notify(sb);
free_anon_bdev(dev);
}
EXPORT_SYMBOL(kill_anon_super);
void kill_litter_super(struct super_block *sb)
{
if (sb->s_root)
d_genocide(sb->s_root);
kill_anon_super(sb);
}
EXPORT_SYMBOL(kill_litter_super);
int set_anon_super_fc(struct super_block *sb, struct fs_context *fc)
{
return set_anon_super(sb, NULL);
}
EXPORT_SYMBOL(set_anon_super_fc);
static int test_keyed_super(struct super_block *sb, struct fs_context *fc)
{
return sb->s_fs_info == fc->s_fs_info;
}
static int test_single_super(struct super_block *s, struct fs_context *fc)
{
return 1;
}
static int vfs_get_super(struct fs_context *fc,
int (*test)(struct super_block *, struct fs_context *),
int (*fill_super)(struct super_block *sb,
struct fs_context *fc))
{
struct super_block *sb;
int err;
sb = sget_fc(fc, test, set_anon_super_fc);
if (IS_ERR(sb))
return PTR_ERR(sb);
if (!sb->s_root) {
err = fill_super(sb, fc);
if (err)
goto error;
sb->s_flags |= SB_ACTIVE;
}
fc->root = dget(sb->s_root);
return 0;
error:
deactivate_locked_super(sb);
return err;
}
int get_tree_nodev(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc))
{
return vfs_get_super(fc, NULL, fill_super);
}
EXPORT_SYMBOL(get_tree_nodev);
int get_tree_single(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc))
{
return vfs_get_super(fc, test_single_super, fill_super);
}
EXPORT_SYMBOL(get_tree_single);
int get_tree_keyed(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc),
void *key)
{
fc->s_fs_info = key;
return vfs_get_super(fc, test_keyed_super, fill_super);
}
EXPORT_SYMBOL(get_tree_keyed);
static int set_bdev_super(struct super_block *s, void *data)
{
s->s_dev = *(dev_t *)data;
return 0;
}
static int super_s_dev_set(struct super_block *s, struct fs_context *fc)
{
return set_bdev_super(s, fc->sget_key);
}
static int super_s_dev_test(struct super_block *s, struct fs_context *fc)
{
return !(s->s_iflags & SB_I_RETIRED) &&
s->s_dev == *(dev_t *)fc->sget_key;
}
/**
* sget_dev - Find or create a superblock by device number
* @fc: Filesystem context.
* @dev: device number
*
* Find or create a superblock using the provided device number that
* will be stored in fc->sget_key.
*
* If an extant superblock is matched, then that will be returned with
* an elevated reference count that the caller must transfer or discard.
*
* If no match is made, a new superblock will be allocated and basic
* initialisation will be performed (s_type, s_fs_info, s_id, s_dev will
* be set). The superblock will be published and it will be returned in
* a partially constructed state with SB_BORN and SB_ACTIVE as yet
* unset.
*
* Return: an existing or newly created superblock on success, an error
* pointer on failure.
*/
struct super_block *sget_dev(struct fs_context *fc, dev_t dev)
{
fc->sget_key = &dev;
return sget_fc(fc, super_s_dev_test, super_s_dev_set);
}
EXPORT_SYMBOL(sget_dev);
#ifdef CONFIG_BLOCK
/*
* Lock a super block that the callers holds a reference to.
*
* The caller needs to ensure that the super_block isn't being freed while
* calling this function, e.g. by holding a lock over the call to this function
* and the place that clears the pointer to the superblock used by this function
* before freeing the superblock.
*/
static bool super_lock_shared_active(struct super_block *sb)
{
bool born = super_lock_shared(sb);
if (!born || !sb->s_root || !(sb->s_flags & SB_ACTIVE)) {
super_unlock_shared(sb);
return false;
}
return true;
}
static void fs_bdev_mark_dead(struct block_device *bdev, bool surprise)
{
struct super_block *sb = bdev->bd_holder;
/* bd_holder_lock ensures that the sb isn't freed */
lockdep_assert_held(&bdev->bd_holder_lock);
if (!super_lock_shared_active(sb))
return;
if (!surprise)
sync_filesystem(sb);
shrink_dcache_sb(sb);
invalidate_inodes(sb);
if (sb->s_op->shutdown)
sb->s_op->shutdown(sb);
super_unlock_shared(sb);
}
static void fs_bdev_sync(struct block_device *bdev)
{
struct super_block *sb = bdev->bd_holder;
lockdep_assert_held(&bdev->bd_holder_lock);
if (!super_lock_shared_active(sb))
return;
sync_filesystem(sb);
super_unlock_shared(sb);
}
const struct blk_holder_ops fs_holder_ops = {
.mark_dead = fs_bdev_mark_dead,
.sync = fs_bdev_sync,
};
EXPORT_SYMBOL_GPL(fs_holder_ops);
int setup_bdev_super(struct super_block *sb, int sb_flags,
struct fs_context *fc)
{
blk_mode_t mode = sb_open_mode(sb_flags);
struct block_device *bdev;
bdev = blkdev_get_by_dev(sb->s_dev, mode, sb, &fs_holder_ops);
if (IS_ERR(bdev)) {
if (fc)
errorf(fc, "%s: Can't open blockdev", fc->source);
return PTR_ERR(bdev);
}
/*
* This really should be in blkdev_get_by_dev, but right now can't due
* to legacy issues that require us to allow opening a block device node
* writable from userspace even for a read-only block device.
*/
if ((mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) {
blkdev_put(bdev, sb);
return -EACCES;
}
/*
* Until SB_BORN flag is set, there can be no active superblock
* references and thus no filesystem freezing. get_active_super() will
* just loop waiting for SB_BORN so even freeze_bdev() cannot proceed.
*
* It is enough to check bdev was not frozen before we set s_bdev.
*/
mutex_lock(&bdev->bd_fsfreeze_mutex);
if (bdev->bd_fsfreeze_count > 0) {
mutex_unlock(&bdev->bd_fsfreeze_mutex);
if (fc)
warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev);
blkdev_put(bdev, sb);
return -EBUSY;
}
spin_lock(&sb_lock);
sb->s_bdev = bdev;
sb->s_bdi = bdi_get(bdev->bd_disk->bdi);
if (bdev_stable_writes(bdev))
sb->s_iflags |= SB_I_STABLE_WRITES;
spin_unlock(&sb_lock);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
shrinker_debugfs_rename(&sb->s_shrink, "sb-%s:%s", sb->s_type->name,
sb->s_id);
sb_set_blocksize(sb, block_size(bdev));
return 0;
}
EXPORT_SYMBOL_GPL(setup_bdev_super);
/**
* get_tree_bdev - Get a superblock based on a single block device
* @fc: The filesystem context holding the parameters
* @fill_super: Helper to initialise a new superblock
*/
int get_tree_bdev(struct fs_context *fc,
int (*fill_super)(struct super_block *,
struct fs_context *))
{
struct super_block *s;
int error = 0;
dev_t dev;
if (!fc->source)
return invalf(fc, "No source specified");
error = lookup_bdev(fc->source, &dev);
if (error) {
errorf(fc, "%s: Can't lookup blockdev", fc->source);
return error;
}
fc->sb_flags |= SB_NOSEC;
s = sget_dev(fc, dev);
if (IS_ERR(s))
return PTR_ERR(s);
if (s->s_root) {
/* Don't summarily change the RO/RW state. */
if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
warnf(fc, "%pg: Can't mount, would change RO state", s->s_bdev);
deactivate_locked_super(s);
return -EBUSY;
}
} else {
/*
* We drop s_umount here because we need to open the bdev and
* bdev->open_mutex ranks above s_umount (blkdev_put() ->
* bdev_mark_dead()). It is safe because we have active sb
* reference and SB_BORN is not set yet.
*/
super_unlock_excl(s);
error = setup_bdev_super(s, fc->sb_flags, fc);
__super_lock_excl(s);
if (!error)
error = fill_super(s, fc);
if (error) {
deactivate_locked_super(s);
return error;
}
s->s_flags |= SB_ACTIVE;
}
BUG_ON(fc->root);
fc->root = dget(s->s_root);
return 0;
}
EXPORT_SYMBOL(get_tree_bdev);
static int test_bdev_super(struct super_block *s, void *data)
{
return !(s->s_iflags & SB_I_RETIRED) && s->s_dev == *(dev_t *)data;
}
struct dentry *mount_bdev(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data,
int (*fill_super)(struct super_block *, void *, int))
{
struct super_block *s;
int error;
dev_t dev;
error = lookup_bdev(dev_name, &dev);
if (error)
return ERR_PTR(error);
flags |= SB_NOSEC;
s = sget(fs_type, test_bdev_super, set_bdev_super, flags, &dev);
if (IS_ERR(s))
return ERR_CAST(s);
if (s->s_root) {
if ((flags ^ s->s_flags) & SB_RDONLY) {
deactivate_locked_super(s);
return ERR_PTR(-EBUSY);
}
} else {
/*
* We drop s_umount here because we need to open the bdev and
* bdev->open_mutex ranks above s_umount (blkdev_put() ->
* bdev_mark_dead()). It is safe because we have active sb
* reference and SB_BORN is not set yet.
*/
super_unlock_excl(s);
error = setup_bdev_super(s, flags, NULL);
__super_lock_excl(s);
if (!error)
error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
s->s_flags |= SB_ACTIVE;
}
return dget(s->s_root);
}
EXPORT_SYMBOL(mount_bdev);
void kill_block_super(struct super_block *sb)
{
struct block_device *bdev = sb->s_bdev;
generic_shutdown_super(sb);
if (bdev) {
sync_blockdev(bdev);
blkdev_put(bdev, sb);
}
}
EXPORT_SYMBOL(kill_block_super);
#endif
struct dentry *mount_nodev(struct file_system_type *fs_type,
int flags, void *data,
int (*fill_super)(struct super_block *, void *, int))
{
int error;
struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL);
if (IS_ERR(s))
return ERR_CAST(s);
error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
s->s_flags |= SB_ACTIVE;
return dget(s->s_root);
}
EXPORT_SYMBOL(mount_nodev);
int reconfigure_single(struct super_block *s,
int flags, void *data)
{
struct fs_context *fc;
int ret;
/* The caller really need to be passing fc down into mount_single(),
* then a chunk of this can be removed. [Bollocks -- AV]
* Better yet, reconfiguration shouldn't happen, but rather the second
* mount should be rejected if the parameters are not compatible.
*/
fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK);
if (IS_ERR(fc))
return PTR_ERR(fc);
ret = parse_monolithic_mount_data(fc, data);
if (ret < 0)
goto out;
ret = reconfigure_super(fc);
out:
put_fs_context(fc);
return ret;
}
static int compare_single(struct super_block *s, void *p)
{
return 1;
}
struct dentry *mount_single(struct file_system_type *fs_type,
int flags, void *data,
int (*fill_super)(struct super_block *, void *, int))
{
struct super_block *s;
int error;
s = sget(fs_type, compare_single, set_anon_super, flags, NULL);
if (IS_ERR(s))
return ERR_CAST(s);
if (!s->s_root) {
error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
if (!error)
s->s_flags |= SB_ACTIVE;
} else {
error = reconfigure_single(s, flags, data);
}
if (unlikely(error)) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
return dget(s->s_root);
}
EXPORT_SYMBOL(mount_single);
/**
* vfs_get_tree - Get the mountable root
* @fc: The superblock configuration context.
*
* The filesystem is invoked to get or create a superblock which can then later
* be used for mounting. The filesystem places a pointer to the root to be
* used for mounting in @fc->root.
*/
int vfs_get_tree(struct fs_context *fc)
{
struct super_block *sb;
int error;
if (fc->root)
return -EBUSY;
/* Get the mountable root in fc->root, with a ref on the root and a ref
* on the superblock.
*/
error = fc->ops->get_tree(fc);
if (error < 0)
return error;
if (!fc->root) {
pr_err("Filesystem %s get_tree() didn't set fc->root\n",
fc->fs_type->name);
/* We don't know what the locking state of the superblock is -
* if there is a superblock.
*/
BUG();
}
sb = fc->root->d_sb;
WARN_ON(!sb->s_bdi);
/*
* super_wake() contains a memory barrier which also care of
* ordering for super_cache_count(). We place it before setting
* SB_BORN as the data dependency between the two functions is
* the superblock structure contents that we just set up, not
* the SB_BORN flag.
*/
super_wake(sb, SB_BORN);
error = security_sb_set_mnt_opts(sb, fc->security, 0, NULL);
if (unlikely(error)) {
fc_drop_locked(fc);
return error;
}
/*
* filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
* but s_maxbytes was an unsigned long long for many releases. Throw
* this warning for a little while to try and catch filesystems that
* violate this rule.
*/
WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
"negative value (%lld)\n", fc->fs_type->name, sb->s_maxbytes);
return 0;
}
EXPORT_SYMBOL(vfs_get_tree);
/*
* Setup private BDI for given superblock. It gets automatically cleaned up
* in generic_shutdown_super().
*/
int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
{
struct backing_dev_info *bdi;
int err;
va_list args;
bdi = bdi_alloc(NUMA_NO_NODE);
if (!bdi)
return -ENOMEM;
va_start(args, fmt);
err = bdi_register_va(bdi, fmt, args);
va_end(args);
if (err) {
bdi_put(bdi);
return err;
}
WARN_ON(sb->s_bdi != &noop_backing_dev_info);
sb->s_bdi = bdi;
sb->s_iflags |= SB_I_PERSB_BDI;
return 0;
}
EXPORT_SYMBOL(super_setup_bdi_name);
/*
* Setup private BDI for given superblock. I gets automatically cleaned up
* in generic_shutdown_super().
*/
int super_setup_bdi(struct super_block *sb)
{
static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name,
atomic_long_inc_return(&bdi_seq));
}
EXPORT_SYMBOL(super_setup_bdi);
/**
* sb_wait_write - wait until all writers to given file system finish
* @sb: the super for which we wait
* @level: type of writers we wait for (normal vs page fault)
*
* This function waits until there are no writers of given type to given file
* system.
*/
static void sb_wait_write(struct super_block *sb, int level)
{
percpu_down_write(sb->s_writers.rw_sem + level-1);
}
/*
* We are going to return to userspace and forget about these locks, the
* ownership goes to the caller of thaw_super() which does unlock().
*/
static void lockdep_sb_freeze_release(struct super_block *sb)
{
int level;
for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--)
percpu_rwsem_release(sb->s_writers.rw_sem + level, 0, _THIS_IP_);
}
/*
* Tell lockdep we are holding these locks before we call ->unfreeze_fs(sb).
*/
static void lockdep_sb_freeze_acquire(struct super_block *sb)
{
int level;
for (level = 0; level < SB_FREEZE_LEVELS; ++level)
percpu_rwsem_acquire(sb->s_writers.rw_sem + level, 0, _THIS_IP_);
}
static void sb_freeze_unlock(struct super_block *sb, int level)
{
for (level--; level >= 0; level--)
percpu_up_write(sb->s_writers.rw_sem + level);
}
static int wait_for_partially_frozen(struct super_block *sb)
{
int ret = 0;
do {
unsigned short old = sb->s_writers.frozen;
up_write(&sb->s_umount);
ret = wait_var_event_killable(&sb->s_writers.frozen,
sb->s_writers.frozen != old);
down_write(&sb->s_umount);
} while (ret == 0 &&
sb->s_writers.frozen != SB_UNFROZEN &&
sb->s_writers.frozen != SB_FREEZE_COMPLETE);
return ret;
}
/**
* freeze_super - lock the filesystem and force it into a consistent state
* @sb: the super to lock
* @who: context that wants to freeze
*
* Syncs the super to make sure the filesystem is consistent and calls the fs's
* freeze_fs. Subsequent calls to this without first thawing the fs may return
* -EBUSY.
*
* @who should be:
* * %FREEZE_HOLDER_USERSPACE if userspace wants to freeze the fs;
* * %FREEZE_HOLDER_KERNEL if the kernel wants to freeze the fs.
*
* The @who argument distinguishes between the kernel and userspace trying to
* freeze the filesystem. Although there cannot be multiple kernel freezes or
* multiple userspace freezes in effect at any given time, the kernel and
* userspace can both hold a filesystem frozen. The filesystem remains frozen
* until there are no kernel or userspace freezes in effect.
*
* During this function, sb->s_writers.frozen goes through these values:
*
* SB_UNFROZEN: File system is normal, all writes progress as usual.
*
* SB_FREEZE_WRITE: The file system is in the process of being frozen. New
* writes should be blocked, though page faults are still allowed. We wait for
* all writes to complete and then proceed to the next stage.
*
* SB_FREEZE_PAGEFAULT: Freezing continues. Now also page faults are blocked
* but internal fs threads can still modify the filesystem (although they
* should not dirty new pages or inodes), writeback can run etc. After waiting
* for all running page faults we sync the filesystem which will clean all
* dirty pages and inodes (no new dirty pages or inodes can be created when
* sync is running).
*
* SB_FREEZE_FS: The file system is frozen. Now all internal sources of fs
* modification are blocked (e.g. XFS preallocation truncation on inode
* reclaim). This is usually implemented by blocking new transactions for
* filesystems that have them and need this additional guard. After all
* internal writers are finished we call ->freeze_fs() to finish filesystem
* freezing. Then we transition to SB_FREEZE_COMPLETE state. This state is
* mostly auxiliary for filesystems to verify they do not modify frozen fs.
*
* sb->s_writers.frozen is protected by sb->s_umount.
*/
int freeze_super(struct super_block *sb, enum freeze_holder who)
{
int ret;
atomic_inc(&sb->s_active);
if (!super_lock_excl(sb))
WARN(1, "Dying superblock while freezing!");
retry:
if (sb->s_writers.frozen == SB_FREEZE_COMPLETE) {
if (sb->s_writers.freeze_holders & who) {
deactivate_locked_super(sb);
return -EBUSY;
}
WARN_ON(sb->s_writers.freeze_holders == 0);
/*
* Someone else already holds this type of freeze; share the
* freeze and assign the active ref to the freeze.
*/
sb->s_writers.freeze_holders |= who;
super_unlock_excl(sb);
return 0;
}
if (sb->s_writers.frozen != SB_UNFROZEN) {
ret = wait_for_partially_frozen(sb);
if (ret) {
deactivate_locked_super(sb);
return ret;
}
goto retry;
}
if (!(sb->s_flags & SB_BORN)) {
super_unlock_excl(sb);
return 0; /* sic - it's "nothing to do" */
}
if (sb_rdonly(sb)) {
/* Nothing to do really... */
sb->s_writers.freeze_holders |= who;
sb->s_writers.frozen = SB_FREEZE_COMPLETE;
wake_up_var(&sb->s_writers.frozen);
super_unlock_excl(sb);
return 0;
}
sb->s_writers.frozen = SB_FREEZE_WRITE;
/* Release s_umount to preserve sb_start_write -> s_umount ordering */
super_unlock_excl(sb);
sb_wait_write(sb, SB_FREEZE_WRITE);
if (!super_lock_excl(sb))
WARN(1, "Dying superblock while freezing!");
/* Now we go and block page faults... */
sb->s_writers.frozen = SB_FREEZE_PAGEFAULT;
sb_wait_write(sb, SB_FREEZE_PAGEFAULT);
/* All writers are done so after syncing there won't be dirty data */
ret = sync_filesystem(sb);
if (ret) {
sb->s_writers.frozen = SB_UNFROZEN;
sb_freeze_unlock(sb, SB_FREEZE_PAGEFAULT);
wake_up_var(&sb->s_writers.frozen);
deactivate_locked_super(sb);
return ret;
}
/* Now wait for internal filesystem counter */
sb->s_writers.frozen = SB_FREEZE_FS;
sb_wait_write(sb, SB_FREEZE_FS);
if (sb->s_op->freeze_fs) {
ret = sb->s_op->freeze_fs(sb);
if (ret) {
printk(KERN_ERR
"VFS:Filesystem freeze failed\n");
sb->s_writers.frozen = SB_UNFROZEN;
sb_freeze_unlock(sb, SB_FREEZE_FS);
wake_up_var(&sb->s_writers.frozen);
deactivate_locked_super(sb);
return ret;
}
}
/*
* For debugging purposes so that fs can warn if it sees write activity
* when frozen is set to SB_FREEZE_COMPLETE, and for thaw_super().
*/
sb->s_writers.freeze_holders |= who;
sb->s_writers.frozen = SB_FREEZE_COMPLETE;
wake_up_var(&sb->s_writers.frozen);
lockdep_sb_freeze_release(sb);
super_unlock_excl(sb);
return 0;
}
EXPORT_SYMBOL(freeze_super);
/*
* Undoes the effect of a freeze_super_locked call. If the filesystem is
* frozen both by userspace and the kernel, a thaw call from either source
* removes that state without releasing the other state or unlocking the
* filesystem.
*/
static int thaw_super_locked(struct super_block *sb, enum freeze_holder who)
{
int error;
if (sb->s_writers.frozen == SB_FREEZE_COMPLETE) {
if (!(sb->s_writers.freeze_holders & who)) {
super_unlock_excl(sb);
return -EINVAL;
}
/*
* Freeze is shared with someone else. Release our hold and
* drop the active ref that freeze_super assigned to the
* freezer.
*/
if (sb->s_writers.freeze_holders & ~who) {
sb->s_writers.freeze_holders &= ~who;
deactivate_locked_super(sb);
return 0;
}
} else {
super_unlock_excl(sb);
return -EINVAL;
}
if (sb_rdonly(sb)) {
sb->s_writers.freeze_holders &= ~who;
sb->s_writers.frozen = SB_UNFROZEN;
wake_up_var(&sb->s_writers.frozen);
goto out;
}
lockdep_sb_freeze_acquire(sb);
if (sb->s_op->unfreeze_fs) {
error = sb->s_op->unfreeze_fs(sb);
if (error) {
printk(KERN_ERR "VFS:Filesystem thaw failed\n");
lockdep_sb_freeze_release(sb);
super_unlock_excl(sb);
return error;
}
}
sb->s_writers.freeze_holders &= ~who;
sb->s_writers.frozen = SB_UNFROZEN;
wake_up_var(&sb->s_writers.frozen);
sb_freeze_unlock(sb, SB_FREEZE_FS);
out:
deactivate_locked_super(sb);
return 0;
}
/**
* thaw_super -- unlock filesystem
* @sb: the super to thaw
* @who: context that wants to freeze
*
* Unlocks the filesystem and marks it writeable again after freeze_super()
* if there are no remaining freezes on the filesystem.
*
* @who should be:
* * %FREEZE_HOLDER_USERSPACE if userspace wants to thaw the fs;
* * %FREEZE_HOLDER_KERNEL if the kernel wants to thaw the fs.
*/
int thaw_super(struct super_block *sb, enum freeze_holder who)
{
if (!super_lock_excl(sb))
WARN(1, "Dying superblock while thawing!");
return thaw_super_locked(sb, who);
}
EXPORT_SYMBOL(thaw_super);
/*
* Create workqueue for deferred direct IO completions. We allocate the
* workqueue when it's first needed. This avoids creating workqueue for
* filesystems that don't need it and also allows us to create the workqueue
* late enough so the we can include s_id in the name of the workqueue.
*/
int sb_init_dio_done_wq(struct super_block *sb)
{
struct workqueue_struct *old;
struct workqueue_struct *wq = alloc_workqueue("dio/%s",
WQ_MEM_RECLAIM, 0,
sb->s_id);
if (!wq)
return -ENOMEM;
/*
* This has to be atomic as more DIOs can race to create the workqueue
*/
old = cmpxchg(&sb->s_dio_done_wq, NULL, wq);
/* Someone created workqueue before us? Free ours... */
if (old)
destroy_workqueue(wq);
return 0;
}
| linux-master | fs/super.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* fs/eventpoll.c (Efficient event retrieval implementation)
* Copyright (C) 2001,...,2009 Davide Libenzi
*
* Davide Libenzi <[email protected]>
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <linux/spinlock.h>
#include <linux/syscalls.h>
#include <linux/rbtree.h>
#include <linux/wait.h>
#include <linux/eventpoll.h>
#include <linux/mount.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/anon_inodes.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/mman.h>
#include <linux/atomic.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/compat.h>
#include <linux/rculist.h>
#include <net/busy_poll.h>
/*
* LOCKING:
* There are three level of locking required by epoll :
*
* 1) epnested_mutex (mutex)
* 2) ep->mtx (mutex)
* 3) ep->lock (rwlock)
*
* The acquire order is the one listed above, from 1 to 3.
* We need a rwlock (ep->lock) because we manipulate objects
* from inside the poll callback, that might be triggered from
* a wake_up() that in turn might be called from IRQ context.
* So we can't sleep inside the poll callback and hence we need
* a spinlock. During the event transfer loop (from kernel to
* user space) we could end up sleeping due a copy_to_user(), so
* we need a lock that will allow us to sleep. This lock is a
* mutex (ep->mtx). It is acquired during the event transfer loop,
* during epoll_ctl(EPOLL_CTL_DEL) and during eventpoll_release_file().
* The epnested_mutex is acquired when inserting an epoll fd onto another
* epoll fd. We do this so that we walk the epoll tree and ensure that this
* insertion does not create a cycle of epoll file descriptors, which
* could lead to deadlock. We need a global mutex to prevent two
* simultaneous inserts (A into B and B into A) from racing and
* constructing a cycle without either insert observing that it is
* going to.
* It is necessary to acquire multiple "ep->mtx"es at once in the
* case when one epoll fd is added to another. In this case, we
* always acquire the locks in the order of nesting (i.e. after
* epoll_ctl(e1, EPOLL_CTL_ADD, e2), e1->mtx will always be acquired
* before e2->mtx). Since we disallow cycles of epoll file
* descriptors, this ensures that the mutexes are well-ordered. In
* order to communicate this nesting to lockdep, when walking a tree
* of epoll file descriptors, we use the current recursion depth as
* the lockdep subkey.
* It is possible to drop the "ep->mtx" and to use the global
* mutex "epnested_mutex" (together with "ep->lock") to have it working,
* but having "ep->mtx" will make the interface more scalable.
* Events that require holding "epnested_mutex" are very rare, while for
* normal operations the epoll private "ep->mtx" will guarantee
* a better scalability.
*/
/* Epoll private bits inside the event mask */
#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE)
#define EPOLLINOUT_BITS (EPOLLIN | EPOLLOUT)
#define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | EPOLLERR | EPOLLHUP | \
EPOLLWAKEUP | EPOLLET | EPOLLEXCLUSIVE)
/* Maximum number of nesting allowed inside epoll sets */
#define EP_MAX_NESTS 4
#define EP_MAX_EVENTS (INT_MAX / sizeof(struct epoll_event))
#define EP_UNACTIVE_PTR ((void *) -1L)
#define EP_ITEM_COST (sizeof(struct epitem) + sizeof(struct eppoll_entry))
struct epoll_filefd {
struct file *file;
int fd;
} __packed;
/* Wait structure used by the poll hooks */
struct eppoll_entry {
/* List header used to link this structure to the "struct epitem" */
struct eppoll_entry *next;
/* The "base" pointer is set to the container "struct epitem" */
struct epitem *base;
/*
* Wait queue item that will be linked to the target file wait
* queue head.
*/
wait_queue_entry_t wait;
/* The wait queue head that linked the "wait" wait queue item */
wait_queue_head_t *whead;
};
/*
* Each file descriptor added to the eventpoll interface will
* have an entry of this type linked to the "rbr" RB tree.
* Avoid increasing the size of this struct, there can be many thousands
* of these on a server and we do not want this to take another cache line.
*/
struct epitem {
union {
/* RB tree node links this structure to the eventpoll RB tree */
struct rb_node rbn;
/* Used to free the struct epitem */
struct rcu_head rcu;
};
/* List header used to link this structure to the eventpoll ready list */
struct list_head rdllink;
/*
* Works together "struct eventpoll"->ovflist in keeping the
* single linked chain of items.
*/
struct epitem *next;
/* The file descriptor information this item refers to */
struct epoll_filefd ffd;
/*
* Protected by file->f_lock, true for to-be-released epitem already
* removed from the "struct file" items list; together with
* eventpoll->refcount orchestrates "struct eventpoll" disposal
*/
bool dying;
/* List containing poll wait queues */
struct eppoll_entry *pwqlist;
/* The "container" of this item */
struct eventpoll *ep;
/* List header used to link this item to the "struct file" items list */
struct hlist_node fllink;
/* wakeup_source used when EPOLLWAKEUP is set */
struct wakeup_source __rcu *ws;
/* The structure that describe the interested events and the source fd */
struct epoll_event event;
};
/*
* This structure is stored inside the "private_data" member of the file
* structure and represents the main data structure for the eventpoll
* interface.
*/
struct eventpoll {
/*
* This mutex is used to ensure that files are not removed
* while epoll is using them. This is held during the event
* collection loop, the file cleanup path, the epoll file exit
* code and the ctl operations.
*/
struct mutex mtx;
/* Wait queue used by sys_epoll_wait() */
wait_queue_head_t wq;
/* Wait queue used by file->poll() */
wait_queue_head_t poll_wait;
/* List of ready file descriptors */
struct list_head rdllist;
/* Lock which protects rdllist and ovflist */
rwlock_t lock;
/* RB tree root used to store monitored fd structs */
struct rb_root_cached rbr;
/*
* This is a single linked list that chains all the "struct epitem" that
* happened while transferring ready events to userspace w/out
* holding ->lock.
*/
struct epitem *ovflist;
/* wakeup_source used when ep_scan_ready_list is running */
struct wakeup_source *ws;
/* The user that created the eventpoll descriptor */
struct user_struct *user;
struct file *file;
/* used to optimize loop detection check */
u64 gen;
struct hlist_head refs;
/*
* usage count, used together with epitem->dying to
* orchestrate the disposal of this struct
*/
refcount_t refcount;
#ifdef CONFIG_NET_RX_BUSY_POLL
/* used to track busy poll napi_id */
unsigned int napi_id;
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
/* tracks wakeup nests for lockdep validation */
u8 nests;
#endif
};
/* Wrapper struct used by poll queueing */
struct ep_pqueue {
poll_table pt;
struct epitem *epi;
};
/*
* Configuration options available inside /proc/sys/fs/epoll/
*/
/* Maximum number of epoll watched descriptors, per user */
static long max_user_watches __read_mostly;
/* Used for cycles detection */
static DEFINE_MUTEX(epnested_mutex);
static u64 loop_check_gen = 0;
/* Used to check for epoll file descriptor inclusion loops */
static struct eventpoll *inserting_into;
/* Slab cache used to allocate "struct epitem" */
static struct kmem_cache *epi_cache __read_mostly;
/* Slab cache used to allocate "struct eppoll_entry" */
static struct kmem_cache *pwq_cache __read_mostly;
/*
* List of files with newly added links, where we may need to limit the number
* of emanating paths. Protected by the epnested_mutex.
*/
struct epitems_head {
struct hlist_head epitems;
struct epitems_head *next;
};
static struct epitems_head *tfile_check_list = EP_UNACTIVE_PTR;
static struct kmem_cache *ephead_cache __read_mostly;
static inline void free_ephead(struct epitems_head *head)
{
if (head)
kmem_cache_free(ephead_cache, head);
}
static void list_file(struct file *file)
{
struct epitems_head *head;
head = container_of(file->f_ep, struct epitems_head, epitems);
if (!head->next) {
head->next = tfile_check_list;
tfile_check_list = head;
}
}
static void unlist_file(struct epitems_head *head)
{
struct epitems_head *to_free = head;
struct hlist_node *p = rcu_dereference(hlist_first_rcu(&head->epitems));
if (p) {
struct epitem *epi= container_of(p, struct epitem, fllink);
spin_lock(&epi->ffd.file->f_lock);
if (!hlist_empty(&head->epitems))
to_free = NULL;
head->next = NULL;
spin_unlock(&epi->ffd.file->f_lock);
}
free_ephead(to_free);
}
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
static long long_zero;
static long long_max = LONG_MAX;
static struct ctl_table epoll_table[] = {
{
.procname = "max_user_watches",
.data = &max_user_watches,
.maxlen = sizeof(max_user_watches),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
.extra1 = &long_zero,
.extra2 = &long_max,
},
{ }
};
static void __init epoll_sysctls_init(void)
{
register_sysctl("fs/epoll", epoll_table);
}
#else
#define epoll_sysctls_init() do { } while (0)
#endif /* CONFIG_SYSCTL */
static const struct file_operations eventpoll_fops;
static inline int is_file_epoll(struct file *f)
{
return f->f_op == &eventpoll_fops;
}
/* Setup the structure that is used as key for the RB tree */
static inline void ep_set_ffd(struct epoll_filefd *ffd,
struct file *file, int fd)
{
ffd->file = file;
ffd->fd = fd;
}
/* Compare RB tree keys */
static inline int ep_cmp_ffd(struct epoll_filefd *p1,
struct epoll_filefd *p2)
{
return (p1->file > p2->file ? +1:
(p1->file < p2->file ? -1 : p1->fd - p2->fd));
}
/* Tells us if the item is currently linked */
static inline int ep_is_linked(struct epitem *epi)
{
return !list_empty(&epi->rdllink);
}
static inline struct eppoll_entry *ep_pwq_from_wait(wait_queue_entry_t *p)
{
return container_of(p, struct eppoll_entry, wait);
}
/* Get the "struct epitem" from a wait queue pointer */
static inline struct epitem *ep_item_from_wait(wait_queue_entry_t *p)
{
return container_of(p, struct eppoll_entry, wait)->base;
}
/**
* ep_events_available - Checks if ready events might be available.
*
* @ep: Pointer to the eventpoll context.
*
* Return: a value different than %zero if ready events are available,
* or %zero otherwise.
*/
static inline int ep_events_available(struct eventpoll *ep)
{
return !list_empty_careful(&ep->rdllist) ||
READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR;
}
#ifdef CONFIG_NET_RX_BUSY_POLL
static bool ep_busy_loop_end(void *p, unsigned long start_time)
{
struct eventpoll *ep = p;
return ep_events_available(ep) || busy_loop_timeout(start_time);
}
/*
* Busy poll if globally on and supporting sockets found && no events,
* busy loop will return if need_resched or ep_events_available.
*
* we must do our busy polling with irqs enabled
*/
static bool ep_busy_loop(struct eventpoll *ep, int nonblock)
{
unsigned int napi_id = READ_ONCE(ep->napi_id);
if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on()) {
napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep, false,
BUSY_POLL_BUDGET);
if (ep_events_available(ep))
return true;
/*
* Busy poll timed out. Drop NAPI ID for now, we can add
* it back in when we have moved a socket with a valid NAPI
* ID onto the ready list.
*/
ep->napi_id = 0;
return false;
}
return false;
}
/*
* Set epoll busy poll NAPI ID from sk.
*/
static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
{
struct eventpoll *ep;
unsigned int napi_id;
struct socket *sock;
struct sock *sk;
if (!net_busy_loop_on())
return;
sock = sock_from_file(epi->ffd.file);
if (!sock)
return;
sk = sock->sk;
if (!sk)
return;
napi_id = READ_ONCE(sk->sk_napi_id);
ep = epi->ep;
/* Non-NAPI IDs can be rejected
* or
* Nothing to do if we already have this ID
*/
if (napi_id < MIN_NAPI_ID || napi_id == ep->napi_id)
return;
/* record NAPI ID for use in next busy poll */
ep->napi_id = napi_id;
}
#else
static inline bool ep_busy_loop(struct eventpoll *ep, int nonblock)
{
return false;
}
static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
{
}
#endif /* CONFIG_NET_RX_BUSY_POLL */
/*
* As described in commit 0ccf831cb lockdep: annotate epoll
* the use of wait queues used by epoll is done in a very controlled
* manner. Wake ups can nest inside each other, but are never done
* with the same locking. For example:
*
* dfd = socket(...);
* efd1 = epoll_create();
* efd2 = epoll_create();
* epoll_ctl(efd1, EPOLL_CTL_ADD, dfd, ...);
* epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...);
*
* When a packet arrives to the device underneath "dfd", the net code will
* issue a wake_up() on its poll wake list. Epoll (efd1) has installed a
* callback wakeup entry on that queue, and the wake_up() performed by the
* "dfd" net code will end up in ep_poll_callback(). At this point epoll
* (efd1) notices that it may have some event ready, so it needs to wake up
* the waiters on its poll wait list (efd2). So it calls ep_poll_safewake()
* that ends up in another wake_up(), after having checked about the
* recursion constraints. That are, no more than EP_MAX_NESTS, to avoid
* stack blasting.
*
* When CONFIG_DEBUG_LOCK_ALLOC is enabled, make sure lockdep can handle
* this special case of epoll.
*/
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi,
unsigned pollflags)
{
struct eventpoll *ep_src;
unsigned long flags;
u8 nests = 0;
/*
* To set the subclass or nesting level for spin_lock_irqsave_nested()
* it might be natural to create a per-cpu nest count. However, since
* we can recurse on ep->poll_wait.lock, and a non-raw spinlock can
* schedule() in the -rt kernel, the per-cpu variable are no longer
* protected. Thus, we are introducing a per eventpoll nest field.
* If we are not being call from ep_poll_callback(), epi is NULL and
* we are at the first level of nesting, 0. Otherwise, we are being
* called from ep_poll_callback() and if a previous wakeup source is
* not an epoll file itself, we are at depth 1 since the wakeup source
* is depth 0. If the wakeup source is a previous epoll file in the
* wakeup chain then we use its nests value and record ours as
* nests + 1. The previous epoll file nests value is stable since its
* already holding its own poll_wait.lock.
*/
if (epi) {
if ((is_file_epoll(epi->ffd.file))) {
ep_src = epi->ffd.file->private_data;
nests = ep_src->nests;
} else {
nests = 1;
}
}
spin_lock_irqsave_nested(&ep->poll_wait.lock, flags, nests);
ep->nests = nests + 1;
wake_up_locked_poll(&ep->poll_wait, EPOLLIN | pollflags);
ep->nests = 0;
spin_unlock_irqrestore(&ep->poll_wait.lock, flags);
}
#else
static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi,
__poll_t pollflags)
{
wake_up_poll(&ep->poll_wait, EPOLLIN | pollflags);
}
#endif
static void ep_remove_wait_queue(struct eppoll_entry *pwq)
{
wait_queue_head_t *whead;
rcu_read_lock();
/*
* If it is cleared by POLLFREE, it should be rcu-safe.
* If we read NULL we need a barrier paired with
* smp_store_release() in ep_poll_callback(), otherwise
* we rely on whead->lock.
*/
whead = smp_load_acquire(&pwq->whead);
if (whead)
remove_wait_queue(whead, &pwq->wait);
rcu_read_unlock();
}
/*
* This function unregisters poll callbacks from the associated file
* descriptor. Must be called with "mtx" held.
*/
static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi)
{
struct eppoll_entry **p = &epi->pwqlist;
struct eppoll_entry *pwq;
while ((pwq = *p) != NULL) {
*p = pwq->next;
ep_remove_wait_queue(pwq);
kmem_cache_free(pwq_cache, pwq);
}
}
/* call only when ep->mtx is held */
static inline struct wakeup_source *ep_wakeup_source(struct epitem *epi)
{
return rcu_dereference_check(epi->ws, lockdep_is_held(&epi->ep->mtx));
}
/* call only when ep->mtx is held */
static inline void ep_pm_stay_awake(struct epitem *epi)
{
struct wakeup_source *ws = ep_wakeup_source(epi);
if (ws)
__pm_stay_awake(ws);
}
static inline bool ep_has_wakeup_source(struct epitem *epi)
{
return rcu_access_pointer(epi->ws) ? true : false;
}
/* call when ep->mtx cannot be held (ep_poll_callback) */
static inline void ep_pm_stay_awake_rcu(struct epitem *epi)
{
struct wakeup_source *ws;
rcu_read_lock();
ws = rcu_dereference(epi->ws);
if (ws)
__pm_stay_awake(ws);
rcu_read_unlock();
}
/*
* ep->mutex needs to be held because we could be hit by
* eventpoll_release_file() and epoll_ctl().
*/
static void ep_start_scan(struct eventpoll *ep, struct list_head *txlist)
{
/*
* Steal the ready list, and re-init the original one to the
* empty list. Also, set ep->ovflist to NULL so that events
* happening while looping w/out locks, are not lost. We cannot
* have the poll callback to queue directly on ep->rdllist,
* because we want the "sproc" callback to be able to do it
* in a lockless way.
*/
lockdep_assert_irqs_enabled();
write_lock_irq(&ep->lock);
list_splice_init(&ep->rdllist, txlist);
WRITE_ONCE(ep->ovflist, NULL);
write_unlock_irq(&ep->lock);
}
static void ep_done_scan(struct eventpoll *ep,
struct list_head *txlist)
{
struct epitem *epi, *nepi;
write_lock_irq(&ep->lock);
/*
* During the time we spent inside the "sproc" callback, some
* other events might have been queued by the poll callback.
* We re-insert them inside the main ready-list here.
*/
for (nepi = READ_ONCE(ep->ovflist); (epi = nepi) != NULL;
nepi = epi->next, epi->next = EP_UNACTIVE_PTR) {
/*
* We need to check if the item is already in the list.
* During the "sproc" callback execution time, items are
* queued into ->ovflist but the "txlist" might already
* contain them, and the list_splice() below takes care of them.
*/
if (!ep_is_linked(epi)) {
/*
* ->ovflist is LIFO, so we have to reverse it in order
* to keep in FIFO.
*/
list_add(&epi->rdllink, &ep->rdllist);
ep_pm_stay_awake(epi);
}
}
/*
* We need to set back ep->ovflist to EP_UNACTIVE_PTR, so that after
* releasing the lock, events will be queued in the normal way inside
* ep->rdllist.
*/
WRITE_ONCE(ep->ovflist, EP_UNACTIVE_PTR);
/*
* Quickly re-inject items left on "txlist".
*/
list_splice(txlist, &ep->rdllist);
__pm_relax(ep->ws);
if (!list_empty(&ep->rdllist)) {
if (waitqueue_active(&ep->wq))
wake_up(&ep->wq);
}
write_unlock_irq(&ep->lock);
}
static void epi_rcu_free(struct rcu_head *head)
{
struct epitem *epi = container_of(head, struct epitem, rcu);
kmem_cache_free(epi_cache, epi);
}
static void ep_get(struct eventpoll *ep)
{
refcount_inc(&ep->refcount);
}
/*
* Returns true if the event poll can be disposed
*/
static bool ep_refcount_dec_and_test(struct eventpoll *ep)
{
if (!refcount_dec_and_test(&ep->refcount))
return false;
WARN_ON_ONCE(!RB_EMPTY_ROOT(&ep->rbr.rb_root));
return true;
}
static void ep_free(struct eventpoll *ep)
{
mutex_destroy(&ep->mtx);
free_uid(ep->user);
wakeup_source_unregister(ep->ws);
kfree(ep);
}
/*
* Removes a "struct epitem" from the eventpoll RB tree and deallocates
* all the associated resources. Must be called with "mtx" held.
* If the dying flag is set, do the removal only if force is true.
* This prevents ep_clear_and_put() from dropping all the ep references
* while running concurrently with eventpoll_release_file().
* Returns true if the eventpoll can be disposed.
*/
static bool __ep_remove(struct eventpoll *ep, struct epitem *epi, bool force)
{
struct file *file = epi->ffd.file;
struct epitems_head *to_free;
struct hlist_head *head;
lockdep_assert_irqs_enabled();
/*
* Removes poll wait queue hooks.
*/
ep_unregister_pollwait(ep, epi);
/* Remove the current item from the list of epoll hooks */
spin_lock(&file->f_lock);
if (epi->dying && !force) {
spin_unlock(&file->f_lock);
return false;
}
to_free = NULL;
head = file->f_ep;
if (head->first == &epi->fllink && !epi->fllink.next) {
file->f_ep = NULL;
if (!is_file_epoll(file)) {
struct epitems_head *v;
v = container_of(head, struct epitems_head, epitems);
if (!smp_load_acquire(&v->next))
to_free = v;
}
}
hlist_del_rcu(&epi->fllink);
spin_unlock(&file->f_lock);
free_ephead(to_free);
rb_erase_cached(&epi->rbn, &ep->rbr);
write_lock_irq(&ep->lock);
if (ep_is_linked(epi))
list_del_init(&epi->rdllink);
write_unlock_irq(&ep->lock);
wakeup_source_unregister(ep_wakeup_source(epi));
/*
* At this point it is safe to free the eventpoll item. Use the union
* field epi->rcu, since we are trying to minimize the size of
* 'struct epitem'. The 'rbn' field is no longer in use. Protected by
* ep->mtx. The rcu read side, reverse_path_check_proc(), does not make
* use of the rbn field.
*/
call_rcu(&epi->rcu, epi_rcu_free);
percpu_counter_dec(&ep->user->epoll_watches);
return ep_refcount_dec_and_test(ep);
}
/*
* ep_remove variant for callers owing an additional reference to the ep
*/
static void ep_remove_safe(struct eventpoll *ep, struct epitem *epi)
{
WARN_ON_ONCE(__ep_remove(ep, epi, false));
}
static void ep_clear_and_put(struct eventpoll *ep)
{
struct rb_node *rbp, *next;
struct epitem *epi;
bool dispose;
/* We need to release all tasks waiting for these file */
if (waitqueue_active(&ep->poll_wait))
ep_poll_safewake(ep, NULL, 0);
mutex_lock(&ep->mtx);
/*
* Walks through the whole tree by unregistering poll callbacks.
*/
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
epi = rb_entry(rbp, struct epitem, rbn);
ep_unregister_pollwait(ep, epi);
cond_resched();
}
/*
* Walks through the whole tree and try to free each "struct epitem".
* Note that ep_remove_safe() will not remove the epitem in case of a
* racing eventpoll_release_file(); the latter will do the removal.
* At this point we are sure no poll callbacks will be lingering around.
* Since we still own a reference to the eventpoll struct, the loop can't
* dispose it.
*/
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = next) {
next = rb_next(rbp);
epi = rb_entry(rbp, struct epitem, rbn);
ep_remove_safe(ep, epi);
cond_resched();
}
dispose = ep_refcount_dec_and_test(ep);
mutex_unlock(&ep->mtx);
if (dispose)
ep_free(ep);
}
static int ep_eventpoll_release(struct inode *inode, struct file *file)
{
struct eventpoll *ep = file->private_data;
if (ep)
ep_clear_and_put(ep);
return 0;
}
static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt, int depth);
static __poll_t __ep_eventpoll_poll(struct file *file, poll_table *wait, int depth)
{
struct eventpoll *ep = file->private_data;
LIST_HEAD(txlist);
struct epitem *epi, *tmp;
poll_table pt;
__poll_t res = 0;
init_poll_funcptr(&pt, NULL);
/* Insert inside our poll wait queue */
poll_wait(file, &ep->poll_wait, wait);
/*
* Proceed to find out if wanted events are really available inside
* the ready list.
*/
mutex_lock_nested(&ep->mtx, depth);
ep_start_scan(ep, &txlist);
list_for_each_entry_safe(epi, tmp, &txlist, rdllink) {
if (ep_item_poll(epi, &pt, depth + 1)) {
res = EPOLLIN | EPOLLRDNORM;
break;
} else {
/*
* Item has been dropped into the ready list by the poll
* callback, but it's not actually ready, as far as
* caller requested events goes. We can remove it here.
*/
__pm_relax(ep_wakeup_source(epi));
list_del_init(&epi->rdllink);
}
}
ep_done_scan(ep, &txlist);
mutex_unlock(&ep->mtx);
return res;
}
/*
* Differs from ep_eventpoll_poll() in that internal callers already have
* the ep->mtx so we need to start from depth=1, such that mutex_lock_nested()
* is correctly annotated.
*/
static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt,
int depth)
{
struct file *file = epi->ffd.file;
__poll_t res;
pt->_key = epi->event.events;
if (!is_file_epoll(file))
res = vfs_poll(file, pt);
else
res = __ep_eventpoll_poll(file, pt, depth);
return res & epi->event.events;
}
static __poll_t ep_eventpoll_poll(struct file *file, poll_table *wait)
{
return __ep_eventpoll_poll(file, wait, 0);
}
#ifdef CONFIG_PROC_FS
static void ep_show_fdinfo(struct seq_file *m, struct file *f)
{
struct eventpoll *ep = f->private_data;
struct rb_node *rbp;
mutex_lock(&ep->mtx);
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
struct epitem *epi = rb_entry(rbp, struct epitem, rbn);
struct inode *inode = file_inode(epi->ffd.file);
seq_printf(m, "tfd: %8d events: %8x data: %16llx "
" pos:%lli ino:%lx sdev:%x\n",
epi->ffd.fd, epi->event.events,
(long long)epi->event.data,
(long long)epi->ffd.file->f_pos,
inode->i_ino, inode->i_sb->s_dev);
if (seq_has_overflowed(m))
break;
}
mutex_unlock(&ep->mtx);
}
#endif
/* File callbacks that implement the eventpoll file behaviour */
static const struct file_operations eventpoll_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = ep_show_fdinfo,
#endif
.release = ep_eventpoll_release,
.poll = ep_eventpoll_poll,
.llseek = noop_llseek,
};
/*
* This is called from eventpoll_release() to unlink files from the eventpoll
* interface. We need to have this facility to cleanup correctly files that are
* closed without being removed from the eventpoll interface.
*/
void eventpoll_release_file(struct file *file)
{
struct eventpoll *ep;
struct epitem *epi;
bool dispose;
/*
* Use the 'dying' flag to prevent a concurrent ep_clear_and_put() from
* touching the epitems list before eventpoll_release_file() can access
* the ep->mtx.
*/
again:
spin_lock(&file->f_lock);
if (file->f_ep && file->f_ep->first) {
epi = hlist_entry(file->f_ep->first, struct epitem, fllink);
epi->dying = true;
spin_unlock(&file->f_lock);
/*
* ep access is safe as we still own a reference to the ep
* struct
*/
ep = epi->ep;
mutex_lock(&ep->mtx);
dispose = __ep_remove(ep, epi, true);
mutex_unlock(&ep->mtx);
if (dispose)
ep_free(ep);
goto again;
}
spin_unlock(&file->f_lock);
}
static int ep_alloc(struct eventpoll **pep)
{
struct eventpoll *ep;
ep = kzalloc(sizeof(*ep), GFP_KERNEL);
if (unlikely(!ep))
return -ENOMEM;
mutex_init(&ep->mtx);
rwlock_init(&ep->lock);
init_waitqueue_head(&ep->wq);
init_waitqueue_head(&ep->poll_wait);
INIT_LIST_HEAD(&ep->rdllist);
ep->rbr = RB_ROOT_CACHED;
ep->ovflist = EP_UNACTIVE_PTR;
ep->user = get_current_user();
refcount_set(&ep->refcount, 1);
*pep = ep;
return 0;
}
/*
* Search the file inside the eventpoll tree. The RB tree operations
* are protected by the "mtx" mutex, and ep_find() must be called with
* "mtx" held.
*/
static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
{
int kcmp;
struct rb_node *rbp;
struct epitem *epi, *epir = NULL;
struct epoll_filefd ffd;
ep_set_ffd(&ffd, file, fd);
for (rbp = ep->rbr.rb_root.rb_node; rbp; ) {
epi = rb_entry(rbp, struct epitem, rbn);
kcmp = ep_cmp_ffd(&ffd, &epi->ffd);
if (kcmp > 0)
rbp = rbp->rb_right;
else if (kcmp < 0)
rbp = rbp->rb_left;
else {
epir = epi;
break;
}
}
return epir;
}
#ifdef CONFIG_KCMP
static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff)
{
struct rb_node *rbp;
struct epitem *epi;
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
epi = rb_entry(rbp, struct epitem, rbn);
if (epi->ffd.fd == tfd) {
if (toff == 0)
return epi;
else
toff--;
}
cond_resched();
}
return NULL;
}
struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd,
unsigned long toff)
{
struct file *file_raw;
struct eventpoll *ep;
struct epitem *epi;
if (!is_file_epoll(file))
return ERR_PTR(-EINVAL);
ep = file->private_data;
mutex_lock(&ep->mtx);
epi = ep_find_tfd(ep, tfd, toff);
if (epi)
file_raw = epi->ffd.file;
else
file_raw = ERR_PTR(-ENOENT);
mutex_unlock(&ep->mtx);
return file_raw;
}
#endif /* CONFIG_KCMP */
/*
* Adds a new entry to the tail of the list in a lockless way, i.e.
* multiple CPUs are allowed to call this function concurrently.
*
* Beware: it is necessary to prevent any other modifications of the
* existing list until all changes are completed, in other words
* concurrent list_add_tail_lockless() calls should be protected
* with a read lock, where write lock acts as a barrier which
* makes sure all list_add_tail_lockless() calls are fully
* completed.
*
* Also an element can be locklessly added to the list only in one
* direction i.e. either to the tail or to the head, otherwise
* concurrent access will corrupt the list.
*
* Return: %false if element has been already added to the list, %true
* otherwise.
*/
static inline bool list_add_tail_lockless(struct list_head *new,
struct list_head *head)
{
struct list_head *prev;
/*
* This is simple 'new->next = head' operation, but cmpxchg()
* is used in order to detect that same element has been just
* added to the list from another CPU: the winner observes
* new->next == new.
*/
if (!try_cmpxchg(&new->next, &new, head))
return false;
/*
* Initially ->next of a new element must be updated with the head
* (we are inserting to the tail) and only then pointers are atomically
* exchanged. XCHG guarantees memory ordering, thus ->next should be
* updated before pointers are actually swapped and pointers are
* swapped before prev->next is updated.
*/
prev = xchg(&head->prev, new);
/*
* It is safe to modify prev->next and new->prev, because a new element
* is added only to the tail and new->next is updated before XCHG.
*/
prev->next = new;
new->prev = prev;
return true;
}
/*
* Chains a new epi entry to the tail of the ep->ovflist in a lockless way,
* i.e. multiple CPUs are allowed to call this function concurrently.
*
* Return: %false if epi element has been already chained, %true otherwise.
*/
static inline bool chain_epi_lockless(struct epitem *epi)
{
struct eventpoll *ep = epi->ep;
/* Fast preliminary check */
if (epi->next != EP_UNACTIVE_PTR)
return false;
/* Check that the same epi has not been just chained from another CPU */
if (cmpxchg(&epi->next, EP_UNACTIVE_PTR, NULL) != EP_UNACTIVE_PTR)
return false;
/* Atomically exchange tail */
epi->next = xchg(&ep->ovflist, epi);
return true;
}
/*
* This is the callback that is passed to the wait queue wakeup
* mechanism. It is called by the stored file descriptors when they
* have events to report.
*
* This callback takes a read lock in order not to contend with concurrent
* events from another file descriptor, thus all modifications to ->rdllist
* or ->ovflist are lockless. Read lock is paired with the write lock from
* ep_scan_ready_list(), which stops all list modifications and guarantees
* that lists state is seen correctly.
*
* Another thing worth to mention is that ep_poll_callback() can be called
* concurrently for the same @epi from different CPUs if poll table was inited
* with several wait queues entries. Plural wakeup from different CPUs of a
* single wait queue is serialized by wq.lock, but the case when multiple wait
* queues are used should be detected accordingly. This is detected using
* cmpxchg() operation.
*/
static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
int pwake = 0;
struct epitem *epi = ep_item_from_wait(wait);
struct eventpoll *ep = epi->ep;
__poll_t pollflags = key_to_poll(key);
unsigned long flags;
int ewake = 0;
read_lock_irqsave(&ep->lock, flags);
ep_set_busy_poll_napi_id(epi);
/*
* If the event mask does not contain any poll(2) event, we consider the
* descriptor to be disabled. This condition is likely the effect of the
* EPOLLONESHOT bit that disables the descriptor when an event is received,
* until the next EPOLL_CTL_MOD will be issued.
*/
if (!(epi->event.events & ~EP_PRIVATE_BITS))
goto out_unlock;
/*
* Check the events coming with the callback. At this stage, not
* every device reports the events in the "key" parameter of the
* callback. We need to be able to handle both cases here, hence the
* test for "key" != NULL before the event match test.
*/
if (pollflags && !(pollflags & epi->event.events))
goto out_unlock;
/*
* If we are transferring events to userspace, we can hold no locks
* (because we're accessing user memory, and because of linux f_op->poll()
* semantics). All the events that happen during that period of time are
* chained in ep->ovflist and requeued later on.
*/
if (READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR) {
if (chain_epi_lockless(epi))
ep_pm_stay_awake_rcu(epi);
} else if (!ep_is_linked(epi)) {
/* In the usual case, add event to ready list. */
if (list_add_tail_lockless(&epi->rdllink, &ep->rdllist))
ep_pm_stay_awake_rcu(epi);
}
/*
* Wake up ( if active ) both the eventpoll wait list and the ->poll()
* wait list.
*/
if (waitqueue_active(&ep->wq)) {
if ((epi->event.events & EPOLLEXCLUSIVE) &&
!(pollflags & POLLFREE)) {
switch (pollflags & EPOLLINOUT_BITS) {
case EPOLLIN:
if (epi->event.events & EPOLLIN)
ewake = 1;
break;
case EPOLLOUT:
if (epi->event.events & EPOLLOUT)
ewake = 1;
break;
case 0:
ewake = 1;
break;
}
}
wake_up(&ep->wq);
}
if (waitqueue_active(&ep->poll_wait))
pwake++;
out_unlock:
read_unlock_irqrestore(&ep->lock, flags);
/* We have to call this outside the lock */
if (pwake)
ep_poll_safewake(ep, epi, pollflags & EPOLL_URING_WAKE);
if (!(epi->event.events & EPOLLEXCLUSIVE))
ewake = 1;
if (pollflags & POLLFREE) {
/*
* If we race with ep_remove_wait_queue() it can miss
* ->whead = NULL and do another remove_wait_queue() after
* us, so we can't use __remove_wait_queue().
*/
list_del_init(&wait->entry);
/*
* ->whead != NULL protects us from the race with
* ep_clear_and_put() or ep_remove(), ep_remove_wait_queue()
* takes whead->lock held by the caller. Once we nullify it,
* nothing protects ep/epi or even wait.
*/
smp_store_release(&ep_pwq_from_wait(wait)->whead, NULL);
}
return ewake;
}
/*
* This is the callback that is used to add our wait queue to the
* target file wakeup lists.
*/
static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
poll_table *pt)
{
struct ep_pqueue *epq = container_of(pt, struct ep_pqueue, pt);
struct epitem *epi = epq->epi;
struct eppoll_entry *pwq;
if (unlikely(!epi)) // an earlier allocation has failed
return;
pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL);
if (unlikely(!pwq)) {
epq->epi = NULL;
return;
}
init_waitqueue_func_entry(&pwq->wait, ep_poll_callback);
pwq->whead = whead;
pwq->base = epi;
if (epi->event.events & EPOLLEXCLUSIVE)
add_wait_queue_exclusive(whead, &pwq->wait);
else
add_wait_queue(whead, &pwq->wait);
pwq->next = epi->pwqlist;
epi->pwqlist = pwq;
}
static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi)
{
int kcmp;
struct rb_node **p = &ep->rbr.rb_root.rb_node, *parent = NULL;
struct epitem *epic;
bool leftmost = true;
while (*p) {
parent = *p;
epic = rb_entry(parent, struct epitem, rbn);
kcmp = ep_cmp_ffd(&epi->ffd, &epic->ffd);
if (kcmp > 0) {
p = &parent->rb_right;
leftmost = false;
} else
p = &parent->rb_left;
}
rb_link_node(&epi->rbn, parent, p);
rb_insert_color_cached(&epi->rbn, &ep->rbr, leftmost);
}
#define PATH_ARR_SIZE 5
/*
* These are the number paths of length 1 to 5, that we are allowing to emanate
* from a single file of interest. For example, we allow 1000 paths of length
* 1, to emanate from each file of interest. This essentially represents the
* potential wakeup paths, which need to be limited in order to avoid massive
* uncontrolled wakeup storms. The common use case should be a single ep which
* is connected to n file sources. In this case each file source has 1 path
* of length 1. Thus, the numbers below should be more than sufficient. These
* path limits are enforced during an EPOLL_CTL_ADD operation, since a modify
* and delete can't add additional paths. Protected by the epnested_mutex.
*/
static const int path_limits[PATH_ARR_SIZE] = { 1000, 500, 100, 50, 10 };
static int path_count[PATH_ARR_SIZE];
static int path_count_inc(int nests)
{
/* Allow an arbitrary number of depth 1 paths */
if (nests == 0)
return 0;
if (++path_count[nests] > path_limits[nests])
return -1;
return 0;
}
static void path_count_init(void)
{
int i;
for (i = 0; i < PATH_ARR_SIZE; i++)
path_count[i] = 0;
}
static int reverse_path_check_proc(struct hlist_head *refs, int depth)
{
int error = 0;
struct epitem *epi;
if (depth > EP_MAX_NESTS) /* too deep nesting */
return -1;
/* CTL_DEL can remove links here, but that can't increase our count */
hlist_for_each_entry_rcu(epi, refs, fllink) {
struct hlist_head *refs = &epi->ep->refs;
if (hlist_empty(refs))
error = path_count_inc(depth);
else
error = reverse_path_check_proc(refs, depth + 1);
if (error != 0)
break;
}
return error;
}
/**
* reverse_path_check - The tfile_check_list is list of epitem_head, which have
* links that are proposed to be newly added. We need to
* make sure that those added links don't add too many
* paths such that we will spend all our time waking up
* eventpoll objects.
*
* Return: %zero if the proposed links don't create too many paths,
* %-1 otherwise.
*/
static int reverse_path_check(void)
{
struct epitems_head *p;
for (p = tfile_check_list; p != EP_UNACTIVE_PTR; p = p->next) {
int error;
path_count_init();
rcu_read_lock();
error = reverse_path_check_proc(&p->epitems, 0);
rcu_read_unlock();
if (error)
return error;
}
return 0;
}
static int ep_create_wakeup_source(struct epitem *epi)
{
struct name_snapshot n;
struct wakeup_source *ws;
if (!epi->ep->ws) {
epi->ep->ws = wakeup_source_register(NULL, "eventpoll");
if (!epi->ep->ws)
return -ENOMEM;
}
take_dentry_name_snapshot(&n, epi->ffd.file->f_path.dentry);
ws = wakeup_source_register(NULL, n.name.name);
release_dentry_name_snapshot(&n);
if (!ws)
return -ENOMEM;
rcu_assign_pointer(epi->ws, ws);
return 0;
}
/* rare code path, only used when EPOLL_CTL_MOD removes a wakeup source */
static noinline void ep_destroy_wakeup_source(struct epitem *epi)
{
struct wakeup_source *ws = ep_wakeup_source(epi);
RCU_INIT_POINTER(epi->ws, NULL);
/*
* wait for ep_pm_stay_awake_rcu to finish, synchronize_rcu is
* used internally by wakeup_source_remove, too (called by
* wakeup_source_unregister), so we cannot use call_rcu
*/
synchronize_rcu();
wakeup_source_unregister(ws);
}
static int attach_epitem(struct file *file, struct epitem *epi)
{
struct epitems_head *to_free = NULL;
struct hlist_head *head = NULL;
struct eventpoll *ep = NULL;
if (is_file_epoll(file))
ep = file->private_data;
if (ep) {
head = &ep->refs;
} else if (!READ_ONCE(file->f_ep)) {
allocate:
to_free = kmem_cache_zalloc(ephead_cache, GFP_KERNEL);
if (!to_free)
return -ENOMEM;
head = &to_free->epitems;
}
spin_lock(&file->f_lock);
if (!file->f_ep) {
if (unlikely(!head)) {
spin_unlock(&file->f_lock);
goto allocate;
}
file->f_ep = head;
to_free = NULL;
}
hlist_add_head_rcu(&epi->fllink, file->f_ep);
spin_unlock(&file->f_lock);
free_ephead(to_free);
return 0;
}
/*
* Must be called with "mtx" held.
*/
static int ep_insert(struct eventpoll *ep, const struct epoll_event *event,
struct file *tfile, int fd, int full_check)
{
int error, pwake = 0;
__poll_t revents;
struct epitem *epi;
struct ep_pqueue epq;
struct eventpoll *tep = NULL;
if (is_file_epoll(tfile))
tep = tfile->private_data;
lockdep_assert_irqs_enabled();
if (unlikely(percpu_counter_compare(&ep->user->epoll_watches,
max_user_watches) >= 0))
return -ENOSPC;
percpu_counter_inc(&ep->user->epoll_watches);
if (!(epi = kmem_cache_zalloc(epi_cache, GFP_KERNEL))) {
percpu_counter_dec(&ep->user->epoll_watches);
return -ENOMEM;
}
/* Item initialization follow here ... */
INIT_LIST_HEAD(&epi->rdllink);
epi->ep = ep;
ep_set_ffd(&epi->ffd, tfile, fd);
epi->event = *event;
epi->next = EP_UNACTIVE_PTR;
if (tep)
mutex_lock_nested(&tep->mtx, 1);
/* Add the current item to the list of active epoll hook for this file */
if (unlikely(attach_epitem(tfile, epi) < 0)) {
if (tep)
mutex_unlock(&tep->mtx);
kmem_cache_free(epi_cache, epi);
percpu_counter_dec(&ep->user->epoll_watches);
return -ENOMEM;
}
if (full_check && !tep)
list_file(tfile);
/*
* Add the current item to the RB tree. All RB tree operations are
* protected by "mtx", and ep_insert() is called with "mtx" held.
*/
ep_rbtree_insert(ep, epi);
if (tep)
mutex_unlock(&tep->mtx);
/*
* ep_remove_safe() calls in the later error paths can't lead to
* ep_free() as the ep file itself still holds an ep reference.
*/
ep_get(ep);
/* now check if we've created too many backpaths */
if (unlikely(full_check && reverse_path_check())) {
ep_remove_safe(ep, epi);
return -EINVAL;
}
if (epi->event.events & EPOLLWAKEUP) {
error = ep_create_wakeup_source(epi);
if (error) {
ep_remove_safe(ep, epi);
return error;
}
}
/* Initialize the poll table using the queue callback */
epq.epi = epi;
init_poll_funcptr(&epq.pt, ep_ptable_queue_proc);
/*
* Attach the item to the poll hooks and get current event bits.
* We can safely use the file* here because its usage count has
* been increased by the caller of this function. Note that after
* this operation completes, the poll callback can start hitting
* the new item.
*/
revents = ep_item_poll(epi, &epq.pt, 1);
/*
* We have to check if something went wrong during the poll wait queue
* install process. Namely an allocation for a wait queue failed due
* high memory pressure.
*/
if (unlikely(!epq.epi)) {
ep_remove_safe(ep, epi);
return -ENOMEM;
}
/* We have to drop the new item inside our item list to keep track of it */
write_lock_irq(&ep->lock);
/* record NAPI ID of new item if present */
ep_set_busy_poll_napi_id(epi);
/* If the file is already "ready" we drop it inside the ready list */
if (revents && !ep_is_linked(epi)) {
list_add_tail(&epi->rdllink, &ep->rdllist);
ep_pm_stay_awake(epi);
/* Notify waiting tasks that events are available */
if (waitqueue_active(&ep->wq))
wake_up(&ep->wq);
if (waitqueue_active(&ep->poll_wait))
pwake++;
}
write_unlock_irq(&ep->lock);
/* We have to call this outside the lock */
if (pwake)
ep_poll_safewake(ep, NULL, 0);
return 0;
}
/*
* Modify the interest event mask by dropping an event if the new mask
* has a match in the current file status. Must be called with "mtx" held.
*/
static int ep_modify(struct eventpoll *ep, struct epitem *epi,
const struct epoll_event *event)
{
int pwake = 0;
poll_table pt;
lockdep_assert_irqs_enabled();
init_poll_funcptr(&pt, NULL);
/*
* Set the new event interest mask before calling f_op->poll();
* otherwise we might miss an event that happens between the
* f_op->poll() call and the new event set registering.
*/
epi->event.events = event->events; /* need barrier below */
epi->event.data = event->data; /* protected by mtx */
if (epi->event.events & EPOLLWAKEUP) {
if (!ep_has_wakeup_source(epi))
ep_create_wakeup_source(epi);
} else if (ep_has_wakeup_source(epi)) {
ep_destroy_wakeup_source(epi);
}
/*
* The following barrier has two effects:
*
* 1) Flush epi changes above to other CPUs. This ensures
* we do not miss events from ep_poll_callback if an
* event occurs immediately after we call f_op->poll().
* We need this because we did not take ep->lock while
* changing epi above (but ep_poll_callback does take
* ep->lock).
*
* 2) We also need to ensure we do not miss _past_ events
* when calling f_op->poll(). This barrier also
* pairs with the barrier in wq_has_sleeper (see
* comments for wq_has_sleeper).
*
* This barrier will now guarantee ep_poll_callback or f_op->poll
* (or both) will notice the readiness of an item.
*/
smp_mb();
/*
* Get current event bits. We can safely use the file* here because
* its usage count has been increased by the caller of this function.
* If the item is "hot" and it is not registered inside the ready
* list, push it inside.
*/
if (ep_item_poll(epi, &pt, 1)) {
write_lock_irq(&ep->lock);
if (!ep_is_linked(epi)) {
list_add_tail(&epi->rdllink, &ep->rdllist);
ep_pm_stay_awake(epi);
/* Notify waiting tasks that events are available */
if (waitqueue_active(&ep->wq))
wake_up(&ep->wq);
if (waitqueue_active(&ep->poll_wait))
pwake++;
}
write_unlock_irq(&ep->lock);
}
/* We have to call this outside the lock */
if (pwake)
ep_poll_safewake(ep, NULL, 0);
return 0;
}
static int ep_send_events(struct eventpoll *ep,
struct epoll_event __user *events, int maxevents)
{
struct epitem *epi, *tmp;
LIST_HEAD(txlist);
poll_table pt;
int res = 0;
/*
* Always short-circuit for fatal signals to allow threads to make a
* timely exit without the chance of finding more events available and
* fetching repeatedly.
*/
if (fatal_signal_pending(current))
return -EINTR;
init_poll_funcptr(&pt, NULL);
mutex_lock(&ep->mtx);
ep_start_scan(ep, &txlist);
/*
* We can loop without lock because we are passed a task private list.
* Items cannot vanish during the loop we are holding ep->mtx.
*/
list_for_each_entry_safe(epi, tmp, &txlist, rdllink) {
struct wakeup_source *ws;
__poll_t revents;
if (res >= maxevents)
break;
/*
* Activate ep->ws before deactivating epi->ws to prevent
* triggering auto-suspend here (in case we reactive epi->ws
* below).
*
* This could be rearranged to delay the deactivation of epi->ws
* instead, but then epi->ws would temporarily be out of sync
* with ep_is_linked().
*/
ws = ep_wakeup_source(epi);
if (ws) {
if (ws->active)
__pm_stay_awake(ep->ws);
__pm_relax(ws);
}
list_del_init(&epi->rdllink);
/*
* If the event mask intersect the caller-requested one,
* deliver the event to userspace. Again, we are holding ep->mtx,
* so no operations coming from userspace can change the item.
*/
revents = ep_item_poll(epi, &pt, 1);
if (!revents)
continue;
events = epoll_put_uevent(revents, epi->event.data, events);
if (!events) {
list_add(&epi->rdllink, &txlist);
ep_pm_stay_awake(epi);
if (!res)
res = -EFAULT;
break;
}
res++;
if (epi->event.events & EPOLLONESHOT)
epi->event.events &= EP_PRIVATE_BITS;
else if (!(epi->event.events & EPOLLET)) {
/*
* If this file has been added with Level
* Trigger mode, we need to insert back inside
* the ready list, so that the next call to
* epoll_wait() will check again the events
* availability. At this point, no one can insert
* into ep->rdllist besides us. The epoll_ctl()
* callers are locked out by
* ep_scan_ready_list() holding "mtx" and the
* poll callback will queue them in ep->ovflist.
*/
list_add_tail(&epi->rdllink, &ep->rdllist);
ep_pm_stay_awake(epi);
}
}
ep_done_scan(ep, &txlist);
mutex_unlock(&ep->mtx);
return res;
}
static struct timespec64 *ep_timeout_to_timespec(struct timespec64 *to, long ms)
{
struct timespec64 now;
if (ms < 0)
return NULL;
if (!ms) {
to->tv_sec = 0;
to->tv_nsec = 0;
return to;
}
to->tv_sec = ms / MSEC_PER_SEC;
to->tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC);
ktime_get_ts64(&now);
*to = timespec64_add_safe(now, *to);
return to;
}
/*
* autoremove_wake_function, but remove even on failure to wake up, because we
* know that default_wake_function/ttwu will only fail if the thread is already
* woken, and in that case the ep_poll loop will remove the entry anyways, not
* try to reuse it.
*/
static int ep_autoremove_wake_function(struct wait_queue_entry *wq_entry,
unsigned int mode, int sync, void *key)
{
int ret = default_wake_function(wq_entry, mode, sync, key);
/*
* Pairs with list_empty_careful in ep_poll, and ensures future loop
* iterations see the cause of this wakeup.
*/
list_del_init_careful(&wq_entry->entry);
return ret;
}
/**
* ep_poll - Retrieves ready events, and delivers them to the caller-supplied
* event buffer.
*
* @ep: Pointer to the eventpoll context.
* @events: Pointer to the userspace buffer where the ready events should be
* stored.
* @maxevents: Size (in terms of number of events) of the caller event buffer.
* @timeout: Maximum timeout for the ready events fetch operation, in
* timespec. If the timeout is zero, the function will not block,
* while if the @timeout ptr is NULL, the function will block
* until at least one event has been retrieved (or an error
* occurred).
*
* Return: the number of ready events which have been fetched, or an
* error code, in case of error.
*/
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
int maxevents, struct timespec64 *timeout)
{
int res, eavail, timed_out = 0;
u64 slack = 0;
wait_queue_entry_t wait;
ktime_t expires, *to = NULL;
lockdep_assert_irqs_enabled();
if (timeout && (timeout->tv_sec | timeout->tv_nsec)) {
slack = select_estimate_accuracy(timeout);
to = &expires;
*to = timespec64_to_ktime(*timeout);
} else if (timeout) {
/*
* Avoid the unnecessary trip to the wait queue loop, if the
* caller specified a non blocking operation.
*/
timed_out = 1;
}
/*
* This call is racy: We may or may not see events that are being added
* to the ready list under the lock (e.g., in IRQ callbacks). For cases
* with a non-zero timeout, this thread will check the ready list under
* lock and will add to the wait queue. For cases with a zero
* timeout, the user by definition should not care and will have to
* recheck again.
*/
eavail = ep_events_available(ep);
while (1) {
if (eavail) {
/*
* Try to transfer events to user space. In case we get
* 0 events and there's still timeout left over, we go
* trying again in search of more luck.
*/
res = ep_send_events(ep, events, maxevents);
if (res)
return res;
}
if (timed_out)
return 0;
eavail = ep_busy_loop(ep, timed_out);
if (eavail)
continue;
if (signal_pending(current))
return -EINTR;
/*
* Internally init_wait() uses autoremove_wake_function(),
* thus wait entry is removed from the wait queue on each
* wakeup. Why it is important? In case of several waiters
* each new wakeup will hit the next waiter, giving it the
* chance to harvest new event. Otherwise wakeup can be
* lost. This is also good performance-wise, because on
* normal wakeup path no need to call __remove_wait_queue()
* explicitly, thus ep->lock is not taken, which halts the
* event delivery.
*
* In fact, we now use an even more aggressive function that
* unconditionally removes, because we don't reuse the wait
* entry between loop iterations. This lets us also avoid the
* performance issue if a process is killed, causing all of its
* threads to wake up without being removed normally.
*/
init_wait(&wait);
wait.func = ep_autoremove_wake_function;
write_lock_irq(&ep->lock);
/*
* Barrierless variant, waitqueue_active() is called under
* the same lock on wakeup ep_poll_callback() side, so it
* is safe to avoid an explicit barrier.
*/
__set_current_state(TASK_INTERRUPTIBLE);
/*
* Do the final check under the lock. ep_scan_ready_list()
* plays with two lists (->rdllist and ->ovflist) and there
* is always a race when both lists are empty for short
* period of time although events are pending, so lock is
* important.
*/
eavail = ep_events_available(ep);
if (!eavail)
__add_wait_queue_exclusive(&ep->wq, &wait);
write_unlock_irq(&ep->lock);
if (!eavail)
timed_out = !schedule_hrtimeout_range(to, slack,
HRTIMER_MODE_ABS);
__set_current_state(TASK_RUNNING);
/*
* We were woken up, thus go and try to harvest some events.
* If timed out and still on the wait queue, recheck eavail
* carefully under lock, below.
*/
eavail = 1;
if (!list_empty_careful(&wait.entry)) {
write_lock_irq(&ep->lock);
/*
* If the thread timed out and is not on the wait queue,
* it means that the thread was woken up after its
* timeout expired before it could reacquire the lock.
* Thus, when wait.entry is empty, it needs to harvest
* events.
*/
if (timed_out)
eavail = list_empty(&wait.entry);
__remove_wait_queue(&ep->wq, &wait);
write_unlock_irq(&ep->lock);
}
}
}
/**
* ep_loop_check_proc - verify that adding an epoll file inside another
* epoll structure does not violate the constraints, in
* terms of closed loops, or too deep chains (which can
* result in excessive stack usage).
*
* @ep: the &struct eventpoll to be currently checked.
* @depth: Current depth of the path being checked.
*
* Return: %zero if adding the epoll @file inside current epoll
* structure @ep does not violate the constraints, or %-1 otherwise.
*/
static int ep_loop_check_proc(struct eventpoll *ep, int depth)
{
int error = 0;
struct rb_node *rbp;
struct epitem *epi;
mutex_lock_nested(&ep->mtx, depth + 1);
ep->gen = loop_check_gen;
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
epi = rb_entry(rbp, struct epitem, rbn);
if (unlikely(is_file_epoll(epi->ffd.file))) {
struct eventpoll *ep_tovisit;
ep_tovisit = epi->ffd.file->private_data;
if (ep_tovisit->gen == loop_check_gen)
continue;
if (ep_tovisit == inserting_into || depth > EP_MAX_NESTS)
error = -1;
else
error = ep_loop_check_proc(ep_tovisit, depth + 1);
if (error != 0)
break;
} else {
/*
* If we've reached a file that is not associated with
* an ep, then we need to check if the newly added
* links are going to add too many wakeup paths. We do
* this by adding it to the tfile_check_list, if it's
* not already there, and calling reverse_path_check()
* during ep_insert().
*/
list_file(epi->ffd.file);
}
}
mutex_unlock(&ep->mtx);
return error;
}
/**
* ep_loop_check - Performs a check to verify that adding an epoll file (@to)
* into another epoll file (represented by @ep) does not create
* closed loops or too deep chains.
*
* @ep: Pointer to the epoll we are inserting into.
* @to: Pointer to the epoll to be inserted.
*
* Return: %zero if adding the epoll @to inside the epoll @from
* does not violate the constraints, or %-1 otherwise.
*/
static int ep_loop_check(struct eventpoll *ep, struct eventpoll *to)
{
inserting_into = ep;
return ep_loop_check_proc(to, 0);
}
static void clear_tfile_check_list(void)
{
rcu_read_lock();
while (tfile_check_list != EP_UNACTIVE_PTR) {
struct epitems_head *head = tfile_check_list;
tfile_check_list = head->next;
unlist_file(head);
}
rcu_read_unlock();
}
/*
* Open an eventpoll file descriptor.
*/
static int do_epoll_create(int flags)
{
int error, fd;
struct eventpoll *ep = NULL;
struct file *file;
/* Check the EPOLL_* constant for consistency. */
BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC);
if (flags & ~EPOLL_CLOEXEC)
return -EINVAL;
/*
* Create the internal data structure ("struct eventpoll").
*/
error = ep_alloc(&ep);
if (error < 0)
return error;
/*
* Creates all the items needed to setup an eventpoll file. That is,
* a file structure and a free file descriptor.
*/
fd = get_unused_fd_flags(O_RDWR | (flags & O_CLOEXEC));
if (fd < 0) {
error = fd;
goto out_free_ep;
}
file = anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep,
O_RDWR | (flags & O_CLOEXEC));
if (IS_ERR(file)) {
error = PTR_ERR(file);
goto out_free_fd;
}
ep->file = file;
fd_install(fd, file);
return fd;
out_free_fd:
put_unused_fd(fd);
out_free_ep:
ep_clear_and_put(ep);
return error;
}
SYSCALL_DEFINE1(epoll_create1, int, flags)
{
return do_epoll_create(flags);
}
SYSCALL_DEFINE1(epoll_create, int, size)
{
if (size <= 0)
return -EINVAL;
return do_epoll_create(0);
}
#ifdef CONFIG_PM_SLEEP
static inline void ep_take_care_of_epollwakeup(struct epoll_event *epev)
{
if ((epev->events & EPOLLWAKEUP) && !capable(CAP_BLOCK_SUSPEND))
epev->events &= ~EPOLLWAKEUP;
}
#else
static inline void ep_take_care_of_epollwakeup(struct epoll_event *epev)
{
epev->events &= ~EPOLLWAKEUP;
}
#endif
static inline int epoll_mutex_lock(struct mutex *mutex, int depth,
bool nonblock)
{
if (!nonblock) {
mutex_lock_nested(mutex, depth);
return 0;
}
if (mutex_trylock(mutex))
return 0;
return -EAGAIN;
}
int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
bool nonblock)
{
int error;
int full_check = 0;
struct fd f, tf;
struct eventpoll *ep;
struct epitem *epi;
struct eventpoll *tep = NULL;
error = -EBADF;
f = fdget(epfd);
if (!f.file)
goto error_return;
/* Get the "struct file *" for the target file */
tf = fdget(fd);
if (!tf.file)
goto error_fput;
/* The target file descriptor must support poll */
error = -EPERM;
if (!file_can_poll(tf.file))
goto error_tgt_fput;
/* Check if EPOLLWAKEUP is allowed */
if (ep_op_has_event(op))
ep_take_care_of_epollwakeup(epds);
/*
* We have to check that the file structure underneath the file descriptor
* the user passed to us _is_ an eventpoll file. And also we do not permit
* adding an epoll file descriptor inside itself.
*/
error = -EINVAL;
if (f.file == tf.file || !is_file_epoll(f.file))
goto error_tgt_fput;
/*
* epoll adds to the wakeup queue at EPOLL_CTL_ADD time only,
* so EPOLLEXCLUSIVE is not allowed for a EPOLL_CTL_MOD operation.
* Also, we do not currently supported nested exclusive wakeups.
*/
if (ep_op_has_event(op) && (epds->events & EPOLLEXCLUSIVE)) {
if (op == EPOLL_CTL_MOD)
goto error_tgt_fput;
if (op == EPOLL_CTL_ADD && (is_file_epoll(tf.file) ||
(epds->events & ~EPOLLEXCLUSIVE_OK_BITS)))
goto error_tgt_fput;
}
/*
* At this point it is safe to assume that the "private_data" contains
* our own data structure.
*/
ep = f.file->private_data;
/*
* When we insert an epoll file descriptor inside another epoll file
* descriptor, there is the chance of creating closed loops, which are
* better be handled here, than in more critical paths. While we are
* checking for loops we also determine the list of files reachable
* and hang them on the tfile_check_list, so we can check that we
* haven't created too many possible wakeup paths.
*
* We do not need to take the global 'epumutex' on EPOLL_CTL_ADD when
* the epoll file descriptor is attaching directly to a wakeup source,
* unless the epoll file descriptor is nested. The purpose of taking the
* 'epnested_mutex' on add is to prevent complex toplogies such as loops and
* deep wakeup paths from forming in parallel through multiple
* EPOLL_CTL_ADD operations.
*/
error = epoll_mutex_lock(&ep->mtx, 0, nonblock);
if (error)
goto error_tgt_fput;
if (op == EPOLL_CTL_ADD) {
if (READ_ONCE(f.file->f_ep) || ep->gen == loop_check_gen ||
is_file_epoll(tf.file)) {
mutex_unlock(&ep->mtx);
error = epoll_mutex_lock(&epnested_mutex, 0, nonblock);
if (error)
goto error_tgt_fput;
loop_check_gen++;
full_check = 1;
if (is_file_epoll(tf.file)) {
tep = tf.file->private_data;
error = -ELOOP;
if (ep_loop_check(ep, tep) != 0)
goto error_tgt_fput;
}
error = epoll_mutex_lock(&ep->mtx, 0, nonblock);
if (error)
goto error_tgt_fput;
}
}
/*
* Try to lookup the file inside our RB tree. Since we grabbed "mtx"
* above, we can be sure to be able to use the item looked up by
* ep_find() till we release the mutex.
*/
epi = ep_find(ep, tf.file, fd);
error = -EINVAL;
switch (op) {
case EPOLL_CTL_ADD:
if (!epi) {
epds->events |= EPOLLERR | EPOLLHUP;
error = ep_insert(ep, epds, tf.file, fd, full_check);
} else
error = -EEXIST;
break;
case EPOLL_CTL_DEL:
if (epi) {
/*
* The eventpoll itself is still alive: the refcount
* can't go to zero here.
*/
ep_remove_safe(ep, epi);
error = 0;
} else {
error = -ENOENT;
}
break;
case EPOLL_CTL_MOD:
if (epi) {
if (!(epi->event.events & EPOLLEXCLUSIVE)) {
epds->events |= EPOLLERR | EPOLLHUP;
error = ep_modify(ep, epi, epds);
}
} else
error = -ENOENT;
break;
}
mutex_unlock(&ep->mtx);
error_tgt_fput:
if (full_check) {
clear_tfile_check_list();
loop_check_gen++;
mutex_unlock(&epnested_mutex);
}
fdput(tf);
error_fput:
fdput(f);
error_return:
return error;
}
/*
* The following function implements the controller interface for
* the eventpoll file that enables the insertion/removal/change of
* file descriptors inside the interest set.
*/
SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
struct epoll_event __user *, event)
{
struct epoll_event epds;
if (ep_op_has_event(op) &&
copy_from_user(&epds, event, sizeof(struct epoll_event)))
return -EFAULT;
return do_epoll_ctl(epfd, op, fd, &epds, false);
}
/*
* Implement the event wait interface for the eventpoll file. It is the kernel
* part of the user space epoll_wait(2).
*/
static int do_epoll_wait(int epfd, struct epoll_event __user *events,
int maxevents, struct timespec64 *to)
{
int error;
struct fd f;
struct eventpoll *ep;
/* The maximum number of event must be greater than zero */
if (maxevents <= 0 || maxevents > EP_MAX_EVENTS)
return -EINVAL;
/* Verify that the area passed by the user is writeable */
if (!access_ok(events, maxevents * sizeof(struct epoll_event)))
return -EFAULT;
/* Get the "struct file *" for the eventpoll file */
f = fdget(epfd);
if (!f.file)
return -EBADF;
/*
* We have to check that the file structure underneath the fd
* the user passed to us _is_ an eventpoll file.
*/
error = -EINVAL;
if (!is_file_epoll(f.file))
goto error_fput;
/*
* At this point it is safe to assume that the "private_data" contains
* our own data structure.
*/
ep = f.file->private_data;
/* Time to fish for events ... */
error = ep_poll(ep, events, maxevents, to);
error_fput:
fdput(f);
return error;
}
SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
int, maxevents, int, timeout)
{
struct timespec64 to;
return do_epoll_wait(epfd, events, maxevents,
ep_timeout_to_timespec(&to, timeout));
}
/*
* Implement the event wait interface for the eventpoll file. It is the kernel
* part of the user space epoll_pwait(2).
*/
static int do_epoll_pwait(int epfd, struct epoll_event __user *events,
int maxevents, struct timespec64 *to,
const sigset_t __user *sigmask, size_t sigsetsize)
{
int error;
/*
* If the caller wants a certain signal mask to be set during the wait,
* we apply it here.
*/
error = set_user_sigmask(sigmask, sigsetsize);
if (error)
return error;
error = do_epoll_wait(epfd, events, maxevents, to);
restore_saved_sigmask_unless(error == -EINTR);
return error;
}
SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
int, maxevents, int, timeout, const sigset_t __user *, sigmask,
size_t, sigsetsize)
{
struct timespec64 to;
return do_epoll_pwait(epfd, events, maxevents,
ep_timeout_to_timespec(&to, timeout),
sigmask, sigsetsize);
}
SYSCALL_DEFINE6(epoll_pwait2, int, epfd, struct epoll_event __user *, events,
int, maxevents, const struct __kernel_timespec __user *, timeout,
const sigset_t __user *, sigmask, size_t, sigsetsize)
{
struct timespec64 ts, *to = NULL;
if (timeout) {
if (get_timespec64(&ts, timeout))
return -EFAULT;
to = &ts;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
return do_epoll_pwait(epfd, events, maxevents, to,
sigmask, sigsetsize);
}
#ifdef CONFIG_COMPAT
static int do_compat_epoll_pwait(int epfd, struct epoll_event __user *events,
int maxevents, struct timespec64 *timeout,
const compat_sigset_t __user *sigmask,
compat_size_t sigsetsize)
{
long err;
/*
* If the caller wants a certain signal mask to be set during the wait,
* we apply it here.
*/
err = set_compat_user_sigmask(sigmask, sigsetsize);
if (err)
return err;
err = do_epoll_wait(epfd, events, maxevents, timeout);
restore_saved_sigmask_unless(err == -EINTR);
return err;
}
COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
struct epoll_event __user *, events,
int, maxevents, int, timeout,
const compat_sigset_t __user *, sigmask,
compat_size_t, sigsetsize)
{
struct timespec64 to;
return do_compat_epoll_pwait(epfd, events, maxevents,
ep_timeout_to_timespec(&to, timeout),
sigmask, sigsetsize);
}
COMPAT_SYSCALL_DEFINE6(epoll_pwait2, int, epfd,
struct epoll_event __user *, events,
int, maxevents,
const struct __kernel_timespec __user *, timeout,
const compat_sigset_t __user *, sigmask,
compat_size_t, sigsetsize)
{
struct timespec64 ts, *to = NULL;
if (timeout) {
if (get_timespec64(&ts, timeout))
return -EFAULT;
to = &ts;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
return do_compat_epoll_pwait(epfd, events, maxevents, to,
sigmask, sigsetsize);
}
#endif
static int __init eventpoll_init(void)
{
struct sysinfo si;
si_meminfo(&si);
/*
* Allows top 4% of lomem to be allocated for epoll watches (per user).
*/
max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) /
EP_ITEM_COST;
BUG_ON(max_user_watches < 0);
/*
* We can have many thousands of epitems, so prevent this from
* using an extra cache line on 64-bit (and smaller) CPUs
*/
BUILD_BUG_ON(sizeof(void *) <= 8 && sizeof(struct epitem) > 128);
/* Allocates slab cache used to allocate "struct epitem" items */
epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem),
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL);
/* Allocates slab cache used to allocate "struct eppoll_entry" */
pwq_cache = kmem_cache_create("eventpoll_pwq",
sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL);
epoll_sysctls_init();
ephead_cache = kmem_cache_create("ep_head",
sizeof(struct epitems_head), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL);
return 0;
}
fs_initcall(eventpoll_init);
| linux-master | fs/eventpoll.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/file_table.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1997 David S. Miller ([email protected])
*/
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/eventpoll.h>
#include <linux/rcupdate.h>
#include <linux/mount.h>
#include <linux/capability.h>
#include <linux/cdev.h>
#include <linux/fsnotify.h>
#include <linux/sysctl.h>
#include <linux/percpu_counter.h>
#include <linux/percpu.h>
#include <linux/task_work.h>
#include <linux/ima.h>
#include <linux/swap.h>
#include <linux/kmemleak.h>
#include <linux/atomic.h>
#include "internal.h"
/* sysctl tunables... */
static struct files_stat_struct files_stat = {
.max_files = NR_FILE
};
/* SLAB cache for file structures */
static struct kmem_cache *filp_cachep __read_mostly;
static struct percpu_counter nr_files __cacheline_aligned_in_smp;
/* Container for backing file with optional real path */
struct backing_file {
struct file file;
struct path real_path;
};
static inline struct backing_file *backing_file(struct file *f)
{
return container_of(f, struct backing_file, file);
}
struct path *backing_file_real_path(struct file *f)
{
return &backing_file(f)->real_path;
}
EXPORT_SYMBOL_GPL(backing_file_real_path);
static void file_free_rcu(struct rcu_head *head)
{
struct file *f = container_of(head, struct file, f_rcuhead);
put_cred(f->f_cred);
if (unlikely(f->f_mode & FMODE_BACKING))
kfree(backing_file(f));
else
kmem_cache_free(filp_cachep, f);
}
static inline void file_free(struct file *f)
{
security_file_free(f);
if (unlikely(f->f_mode & FMODE_BACKING))
path_put(backing_file_real_path(f));
if (likely(!(f->f_mode & FMODE_NOACCOUNT)))
percpu_counter_dec(&nr_files);
call_rcu(&f->f_rcuhead, file_free_rcu);
}
/*
* Return the total number of open files in the system
*/
static long get_nr_files(void)
{
return percpu_counter_read_positive(&nr_files);
}
/*
* Return the maximum number of open files in the system
*/
unsigned long get_max_files(void)
{
return files_stat.max_files;
}
EXPORT_SYMBOL_GPL(get_max_files);
#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
/*
* Handle nr_files sysctl
*/
static int proc_nr_files(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
files_stat.nr_files = get_nr_files();
return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
}
static struct ctl_table fs_stat_sysctls[] = {
{
.procname = "file-nr",
.data = &files_stat,
.maxlen = sizeof(files_stat),
.mode = 0444,
.proc_handler = proc_nr_files,
},
{
.procname = "file-max",
.data = &files_stat.max_files,
.maxlen = sizeof(files_stat.max_files),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
.extra1 = SYSCTL_LONG_ZERO,
.extra2 = SYSCTL_LONG_MAX,
},
{
.procname = "nr_open",
.data = &sysctl_nr_open,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &sysctl_nr_open_min,
.extra2 = &sysctl_nr_open_max,
},
{ }
};
static int __init init_fs_stat_sysctls(void)
{
register_sysctl_init("fs", fs_stat_sysctls);
if (IS_ENABLED(CONFIG_BINFMT_MISC)) {
struct ctl_table_header *hdr;
hdr = register_sysctl_mount_point("fs/binfmt_misc");
kmemleak_not_leak(hdr);
}
return 0;
}
fs_initcall(init_fs_stat_sysctls);
#endif
static int init_file(struct file *f, int flags, const struct cred *cred)
{
int error;
f->f_cred = get_cred(cred);
error = security_file_alloc(f);
if (unlikely(error)) {
put_cred(f->f_cred);
return error;
}
atomic_long_set(&f->f_count, 1);
rwlock_init(&f->f_owner.lock);
spin_lock_init(&f->f_lock);
mutex_init(&f->f_pos_lock);
f->f_flags = flags;
f->f_mode = OPEN_FMODE(flags);
/* f->f_version: 0 */
return 0;
}
/* Find an unused file structure and return a pointer to it.
* Returns an error pointer if some error happend e.g. we over file
* structures limit, run out of memory or operation is not permitted.
*
* Be very careful using this. You are responsible for
* getting write access to any mount that you might assign
* to this filp, if it is opened for write. If this is not
* done, you will imbalance int the mount's writer count
* and a warning at __fput() time.
*/
struct file *alloc_empty_file(int flags, const struct cred *cred)
{
static long old_max;
struct file *f;
int error;
/*
* Privileged users can go above max_files
*/
if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) {
/*
* percpu_counters are inaccurate. Do an expensive check before
* we go and fail.
*/
if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files)
goto over;
}
f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
if (unlikely(!f))
return ERR_PTR(-ENOMEM);
error = init_file(f, flags, cred);
if (unlikely(error)) {
kmem_cache_free(filp_cachep, f);
return ERR_PTR(error);
}
percpu_counter_inc(&nr_files);
return f;
over:
/* Ran out of filps - report that */
if (get_nr_files() > old_max) {
pr_info("VFS: file-max limit %lu reached\n", get_max_files());
old_max = get_nr_files();
}
return ERR_PTR(-ENFILE);
}
/*
* Variant of alloc_empty_file() that doesn't check and modify nr_files.
*
* This is only for kernel internal use, and the allocate file must not be
* installed into file tables or such.
*/
struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred)
{
struct file *f;
int error;
f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
if (unlikely(!f))
return ERR_PTR(-ENOMEM);
error = init_file(f, flags, cred);
if (unlikely(error)) {
kmem_cache_free(filp_cachep, f);
return ERR_PTR(error);
}
f->f_mode |= FMODE_NOACCOUNT;
return f;
}
/*
* Variant of alloc_empty_file() that allocates a backing_file container
* and doesn't check and modify nr_files.
*
* This is only for kernel internal use, and the allocate file must not be
* installed into file tables or such.
*/
struct file *alloc_empty_backing_file(int flags, const struct cred *cred)
{
struct backing_file *ff;
int error;
ff = kzalloc(sizeof(struct backing_file), GFP_KERNEL);
if (unlikely(!ff))
return ERR_PTR(-ENOMEM);
error = init_file(&ff->file, flags, cred);
if (unlikely(error)) {
kfree(ff);
return ERR_PTR(error);
}
ff->file.f_mode |= FMODE_BACKING | FMODE_NOACCOUNT;
return &ff->file;
}
/**
* alloc_file - allocate and initialize a 'struct file'
*
* @path: the (dentry, vfsmount) pair for the new file
* @flags: O_... flags with which the new file will be opened
* @fop: the 'struct file_operations' for the new file
*/
static struct file *alloc_file(const struct path *path, int flags,
const struct file_operations *fop)
{
struct file *file;
file = alloc_empty_file(flags, current_cred());
if (IS_ERR(file))
return file;
file->f_path = *path;
file->f_inode = path->dentry->d_inode;
file->f_mapping = path->dentry->d_inode->i_mapping;
file->f_wb_err = filemap_sample_wb_err(file->f_mapping);
file->f_sb_err = file_sample_sb_err(file);
if (fop->llseek)
file->f_mode |= FMODE_LSEEK;
if ((file->f_mode & FMODE_READ) &&
likely(fop->read || fop->read_iter))
file->f_mode |= FMODE_CAN_READ;
if ((file->f_mode & FMODE_WRITE) &&
likely(fop->write || fop->write_iter))
file->f_mode |= FMODE_CAN_WRITE;
file->f_iocb_flags = iocb_flags(file);
file->f_mode |= FMODE_OPENED;
file->f_op = fop;
if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
i_readcount_inc(path->dentry->d_inode);
return file;
}
struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt,
const char *name, int flags,
const struct file_operations *fops)
{
static const struct dentry_operations anon_ops = {
.d_dname = simple_dname
};
struct qstr this = QSTR_INIT(name, strlen(name));
struct path path;
struct file *file;
path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this);
if (!path.dentry)
return ERR_PTR(-ENOMEM);
if (!mnt->mnt_sb->s_d_op)
d_set_d_op(path.dentry, &anon_ops);
path.mnt = mntget(mnt);
d_instantiate(path.dentry, inode);
file = alloc_file(&path, flags, fops);
if (IS_ERR(file)) {
ihold(inode);
path_put(&path);
}
return file;
}
EXPORT_SYMBOL(alloc_file_pseudo);
struct file *alloc_file_clone(struct file *base, int flags,
const struct file_operations *fops)
{
struct file *f = alloc_file(&base->f_path, flags, fops);
if (!IS_ERR(f)) {
path_get(&f->f_path);
f->f_mapping = base->f_mapping;
}
return f;
}
/* the real guts of fput() - releasing the last reference to file
*/
static void __fput(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct vfsmount *mnt = file->f_path.mnt;
struct inode *inode = file->f_inode;
fmode_t mode = file->f_mode;
if (unlikely(!(file->f_mode & FMODE_OPENED)))
goto out;
might_sleep();
fsnotify_close(file);
/*
* The function eventpoll_release() should be the first called
* in the file cleanup chain.
*/
eventpoll_release(file);
locks_remove_file(file);
ima_file_free(file);
if (unlikely(file->f_flags & FASYNC)) {
if (file->f_op->fasync)
file->f_op->fasync(-1, file, 0);
}
if (file->f_op->release)
file->f_op->release(inode, file);
if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL &&
!(mode & FMODE_PATH))) {
cdev_put(inode->i_cdev);
}
fops_put(file->f_op);
put_pid(file->f_owner.pid);
put_file_access(file);
dput(dentry);
if (unlikely(mode & FMODE_NEED_UNMOUNT))
dissolve_on_fput(mnt);
mntput(mnt);
out:
file_free(file);
}
static LLIST_HEAD(delayed_fput_list);
static void delayed_fput(struct work_struct *unused)
{
struct llist_node *node = llist_del_all(&delayed_fput_list);
struct file *f, *t;
llist_for_each_entry_safe(f, t, node, f_llist)
__fput(f);
}
static void ____fput(struct callback_head *work)
{
__fput(container_of(work, struct file, f_rcuhead));
}
/*
* If kernel thread really needs to have the final fput() it has done
* to complete, call this. The only user right now is the boot - we
* *do* need to make sure our writes to binaries on initramfs has
* not left us with opened struct file waiting for __fput() - execve()
* won't work without that. Please, don't add more callers without
* very good reasons; in particular, never call that with locks
* held and never call that from a thread that might need to do
* some work on any kind of umount.
*/
void flush_delayed_fput(void)
{
delayed_fput(NULL);
}
EXPORT_SYMBOL_GPL(flush_delayed_fput);
static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput);
void fput(struct file *file)
{
if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
init_task_work(&file->f_rcuhead, ____fput);
if (!task_work_add(task, &file->f_rcuhead, TWA_RESUME))
return;
/*
* After this task has run exit_task_work(),
* task_work_add() will fail. Fall through to delayed
* fput to avoid leaking *file.
*/
}
if (llist_add(&file->f_llist, &delayed_fput_list))
schedule_delayed_work(&delayed_fput_work, 1);
}
}
/*
* synchronous analog of fput(); for kernel threads that might be needed
* in some umount() (and thus can't use flush_delayed_fput() without
* risking deadlocks), need to wait for completion of __fput() and know
* for this specific struct file it won't involve anything that would
* need them. Use only if you really need it - at the very least,
* don't blindly convert fput() by kernel thread to that.
*/
void __fput_sync(struct file *file)
{
if (atomic_long_dec_and_test(&file->f_count))
__fput(file);
}
EXPORT_SYMBOL(fput);
EXPORT_SYMBOL(__fput_sync);
void __init files_init(void)
{
filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, NULL);
percpu_counter_init(&nr_files, 0, GFP_KERNEL);
}
/*
* One file with associated inode and dcache is very roughly 1K. Per default
* do not use more than 10% of our memory for files.
*/
void __init files_maxfiles_init(void)
{
unsigned long n;
unsigned long nr_pages = totalram_pages();
unsigned long memreserve = (nr_pages - nr_free_pages()) * 3/2;
memreserve = min(memreserve, nr_pages - 1);
n = ((nr_pages - memreserve) * (PAGE_SIZE / 1024)) / 10;
files_stat.max_files = max_t(unsigned long, n, NR_FILE);
}
| linux-master | fs/file_table.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "internal.h"
#include "mount.h"
static DEFINE_SPINLOCK(pin_lock);
void pin_remove(struct fs_pin *pin)
{
spin_lock(&pin_lock);
hlist_del_init(&pin->m_list);
hlist_del_init(&pin->s_list);
spin_unlock(&pin_lock);
spin_lock_irq(&pin->wait.lock);
pin->done = 1;
wake_up_locked(&pin->wait);
spin_unlock_irq(&pin->wait.lock);
}
void pin_insert(struct fs_pin *pin, struct vfsmount *m)
{
spin_lock(&pin_lock);
hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);
hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
spin_unlock(&pin_lock);
}
void pin_kill(struct fs_pin *p)
{
wait_queue_entry_t wait;
if (!p) {
rcu_read_unlock();
return;
}
init_wait(&wait);
spin_lock_irq(&p->wait.lock);
if (likely(!p->done)) {
p->done = -1;
spin_unlock_irq(&p->wait.lock);
rcu_read_unlock();
p->kill(p);
return;
}
if (p->done > 0) {
spin_unlock_irq(&p->wait.lock);
rcu_read_unlock();
return;
}
__add_wait_queue(&p->wait, &wait);
while (1) {
set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&p->wait.lock);
rcu_read_unlock();
schedule();
rcu_read_lock();
if (likely(list_empty(&wait.entry)))
break;
/* OK, we know p couldn't have been freed yet */
spin_lock_irq(&p->wait.lock);
if (p->done > 0) {
spin_unlock_irq(&p->wait.lock);
break;
}
}
rcu_read_unlock();
}
void mnt_pin_kill(struct mount *m)
{
while (1) {
struct hlist_node *p;
rcu_read_lock();
p = READ_ONCE(m->mnt_pins.first);
if (!p) {
rcu_read_unlock();
break;
}
pin_kill(hlist_entry(p, struct fs_pin, m_list));
}
}
void group_pin_kill(struct hlist_head *p)
{
while (1) {
struct hlist_node *q;
rcu_read_lock();
q = READ_ONCE(p->first);
if (!q) {
rcu_read_unlock();
break;
}
pin_kill(hlist_entry(q, struct fs_pin, s_list));
}
}
| linux-master | fs/fs_pin.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/buffer.c
*
* Copyright (C) 1991, 1992, 2002 Linus Torvalds
*/
/*
* Start bdflush() with kernel_thread not syscall - Paul Gortmaker, 12/95
*
* Removed a lot of unnecessary code and simplified things now that
* the buffer cache isn't our primary cache - Andrew Tridgell 12/96
*
* Speed up hash, lru, and free list operations. Use gfp() for allocating
* hash table, use SLAB cache for buffer heads. SMP threading. -DaveM
*
* Added 32k buffer block sizes - these are required older ARM systems. - RMK
*
* async buffer flushing, 1999 Andrea Arcangeli <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/syscalls.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/mm.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/capability.h>
#include <linux/blkdev.h>
#include <linux/file.h>
#include <linux/quotaops.h>
#include <linux/highmem.h>
#include <linux/export.h>
#include <linux/backing-dev.h>
#include <linux/writeback.h>
#include <linux/hash.h>
#include <linux/suspend.h>
#include <linux/buffer_head.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/bio.h>
#include <linux/cpu.h>
#include <linux/bitops.h>
#include <linux/mpage.h>
#include <linux/bit_spinlock.h>
#include <linux/pagevec.h>
#include <linux/sched/mm.h>
#include <trace/events/block.h>
#include <linux/fscrypt.h>
#include <linux/fsverity.h>
#include <linux/sched/isolation.h>
#include "internal.h"
static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
static void submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh,
struct writeback_control *wbc);
#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)
inline void touch_buffer(struct buffer_head *bh)
{
trace_block_touch_buffer(bh);
folio_mark_accessed(bh->b_folio);
}
EXPORT_SYMBOL(touch_buffer);
void __lock_buffer(struct buffer_head *bh)
{
wait_on_bit_lock_io(&bh->b_state, BH_Lock, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(__lock_buffer);
void unlock_buffer(struct buffer_head *bh)
{
clear_bit_unlock(BH_Lock, &bh->b_state);
smp_mb__after_atomic();
wake_up_bit(&bh->b_state, BH_Lock);
}
EXPORT_SYMBOL(unlock_buffer);
/*
* Returns if the folio has dirty or writeback buffers. If all the buffers
* are unlocked and clean then the folio_test_dirty information is stale. If
* any of the buffers are locked, it is assumed they are locked for IO.
*/
void buffer_check_dirty_writeback(struct folio *folio,
bool *dirty, bool *writeback)
{
struct buffer_head *head, *bh;
*dirty = false;
*writeback = false;
BUG_ON(!folio_test_locked(folio));
head = folio_buffers(folio);
if (!head)
return;
if (folio_test_writeback(folio))
*writeback = true;
bh = head;
do {
if (buffer_locked(bh))
*writeback = true;
if (buffer_dirty(bh))
*dirty = true;
bh = bh->b_this_page;
} while (bh != head);
}
/*
* Block until a buffer comes unlocked. This doesn't stop it
* from becoming locked again - you have to lock it yourself
* if you want to preserve its state.
*/
void __wait_on_buffer(struct buffer_head * bh)
{
wait_on_bit_io(&bh->b_state, BH_Lock, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(__wait_on_buffer);
static void buffer_io_error(struct buffer_head *bh, char *msg)
{
if (!test_bit(BH_Quiet, &bh->b_state))
printk_ratelimited(KERN_ERR
"Buffer I/O error on dev %pg, logical block %llu%s\n",
bh->b_bdev, (unsigned long long)bh->b_blocknr, msg);
}
/*
* End-of-IO handler helper function which does not touch the bh after
* unlocking it.
* Note: unlock_buffer() sort-of does touch the bh after unlocking it, but
* a race there is benign: unlock_buffer() only use the bh's address for
* hashing after unlocking the buffer, so it doesn't actually touch the bh
* itself.
*/
static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate)
{
if (uptodate) {
set_buffer_uptodate(bh);
} else {
/* This happens, due to failed read-ahead attempts. */
clear_buffer_uptodate(bh);
}
unlock_buffer(bh);
}
/*
* Default synchronous end-of-IO handler.. Just mark it up-to-date and
* unlock the buffer.
*/
void end_buffer_read_sync(struct buffer_head *bh, int uptodate)
{
__end_buffer_read_notouch(bh, uptodate);
put_bh(bh);
}
EXPORT_SYMBOL(end_buffer_read_sync);
void end_buffer_write_sync(struct buffer_head *bh, int uptodate)
{
if (uptodate) {
set_buffer_uptodate(bh);
} else {
buffer_io_error(bh, ", lost sync page write");
mark_buffer_write_io_error(bh);
clear_buffer_uptodate(bh);
}
unlock_buffer(bh);
put_bh(bh);
}
EXPORT_SYMBOL(end_buffer_write_sync);
/*
* Various filesystems appear to want __find_get_block to be non-blocking.
* But it's the page lock which protects the buffers. To get around this,
* we get exclusion from try_to_free_buffers with the blockdev mapping's
* private_lock.
*
* Hack idea: for the blockdev mapping, private_lock contention
* may be quite high. This code could TryLock the page, and if that
* succeeds, there is no need to take private_lock.
*/
static struct buffer_head *
__find_get_block_slow(struct block_device *bdev, sector_t block)
{
struct inode *bd_inode = bdev->bd_inode;
struct address_space *bd_mapping = bd_inode->i_mapping;
struct buffer_head *ret = NULL;
pgoff_t index;
struct buffer_head *bh;
struct buffer_head *head;
struct folio *folio;
int all_mapped = 1;
static DEFINE_RATELIMIT_STATE(last_warned, HZ, 1);
index = block >> (PAGE_SHIFT - bd_inode->i_blkbits);
folio = __filemap_get_folio(bd_mapping, index, FGP_ACCESSED, 0);
if (IS_ERR(folio))
goto out;
spin_lock(&bd_mapping->private_lock);
head = folio_buffers(folio);
if (!head)
goto out_unlock;
bh = head;
do {
if (!buffer_mapped(bh))
all_mapped = 0;
else if (bh->b_blocknr == block) {
ret = bh;
get_bh(bh);
goto out_unlock;
}
bh = bh->b_this_page;
} while (bh != head);
/* we might be here because some of the buffers on this page are
* not mapped. This is due to various races between
* file io on the block device and getblk. It gets dealt with
* elsewhere, don't buffer_error if we had some unmapped buffers
*/
ratelimit_set_flags(&last_warned, RATELIMIT_MSG_ON_RELEASE);
if (all_mapped && __ratelimit(&last_warned)) {
printk("__find_get_block_slow() failed. block=%llu, "
"b_blocknr=%llu, b_state=0x%08lx, b_size=%zu, "
"device %pg blocksize: %d\n",
(unsigned long long)block,
(unsigned long long)bh->b_blocknr,
bh->b_state, bh->b_size, bdev,
1 << bd_inode->i_blkbits);
}
out_unlock:
spin_unlock(&bd_mapping->private_lock);
folio_put(folio);
out:
return ret;
}
static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
{
unsigned long flags;
struct buffer_head *first;
struct buffer_head *tmp;
struct folio *folio;
int folio_uptodate = 1;
BUG_ON(!buffer_async_read(bh));
folio = bh->b_folio;
if (uptodate) {
set_buffer_uptodate(bh);
} else {
clear_buffer_uptodate(bh);
buffer_io_error(bh, ", async page read");
folio_set_error(folio);
}
/*
* Be _very_ careful from here on. Bad things can happen if
* two buffer heads end IO at almost the same time and both
* decide that the page is now completely done.
*/
first = folio_buffers(folio);
spin_lock_irqsave(&first->b_uptodate_lock, flags);
clear_buffer_async_read(bh);
unlock_buffer(bh);
tmp = bh;
do {
if (!buffer_uptodate(tmp))
folio_uptodate = 0;
if (buffer_async_read(tmp)) {
BUG_ON(!buffer_locked(tmp));
goto still_busy;
}
tmp = tmp->b_this_page;
} while (tmp != bh);
spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
/*
* If all of the buffers are uptodate then we can set the page
* uptodate.
*/
if (folio_uptodate)
folio_mark_uptodate(folio);
folio_unlock(folio);
return;
still_busy:
spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
return;
}
struct postprocess_bh_ctx {
struct work_struct work;
struct buffer_head *bh;
};
static void verify_bh(struct work_struct *work)
{
struct postprocess_bh_ctx *ctx =
container_of(work, struct postprocess_bh_ctx, work);
struct buffer_head *bh = ctx->bh;
bool valid;
valid = fsverity_verify_blocks(bh->b_folio, bh->b_size, bh_offset(bh));
end_buffer_async_read(bh, valid);
kfree(ctx);
}
static bool need_fsverity(struct buffer_head *bh)
{
struct folio *folio = bh->b_folio;
struct inode *inode = folio->mapping->host;
return fsverity_active(inode) &&
/* needed by ext4 */
folio->index < DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
}
static void decrypt_bh(struct work_struct *work)
{
struct postprocess_bh_ctx *ctx =
container_of(work, struct postprocess_bh_ctx, work);
struct buffer_head *bh = ctx->bh;
int err;
err = fscrypt_decrypt_pagecache_blocks(bh->b_folio, bh->b_size,
bh_offset(bh));
if (err == 0 && need_fsverity(bh)) {
/*
* We use different work queues for decryption and for verity
* because verity may require reading metadata pages that need
* decryption, and we shouldn't recurse to the same workqueue.
*/
INIT_WORK(&ctx->work, verify_bh);
fsverity_enqueue_verify_work(&ctx->work);
return;
}
end_buffer_async_read(bh, err == 0);
kfree(ctx);
}
/*
* I/O completion handler for block_read_full_folio() - pages
* which come unlocked at the end of I/O.
*/
static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate)
{
struct inode *inode = bh->b_folio->mapping->host;
bool decrypt = fscrypt_inode_uses_fs_layer_crypto(inode);
bool verify = need_fsverity(bh);
/* Decrypt (with fscrypt) and/or verify (with fsverity) if needed. */
if (uptodate && (decrypt || verify)) {
struct postprocess_bh_ctx *ctx =
kmalloc(sizeof(*ctx), GFP_ATOMIC);
if (ctx) {
ctx->bh = bh;
if (decrypt) {
INIT_WORK(&ctx->work, decrypt_bh);
fscrypt_enqueue_decrypt_work(&ctx->work);
} else {
INIT_WORK(&ctx->work, verify_bh);
fsverity_enqueue_verify_work(&ctx->work);
}
return;
}
uptodate = 0;
}
end_buffer_async_read(bh, uptodate);
}
/*
* Completion handler for block_write_full_page() - pages which are unlocked
* during I/O, and which have PageWriteback cleared upon I/O completion.
*/
void end_buffer_async_write(struct buffer_head *bh, int uptodate)
{
unsigned long flags;
struct buffer_head *first;
struct buffer_head *tmp;
struct folio *folio;
BUG_ON(!buffer_async_write(bh));
folio = bh->b_folio;
if (uptodate) {
set_buffer_uptodate(bh);
} else {
buffer_io_error(bh, ", lost async page write");
mark_buffer_write_io_error(bh);
clear_buffer_uptodate(bh);
folio_set_error(folio);
}
first = folio_buffers(folio);
spin_lock_irqsave(&first->b_uptodate_lock, flags);
clear_buffer_async_write(bh);
unlock_buffer(bh);
tmp = bh->b_this_page;
while (tmp != bh) {
if (buffer_async_write(tmp)) {
BUG_ON(!buffer_locked(tmp));
goto still_busy;
}
tmp = tmp->b_this_page;
}
spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
folio_end_writeback(folio);
return;
still_busy:
spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
return;
}
EXPORT_SYMBOL(end_buffer_async_write);
/*
* If a page's buffers are under async readin (end_buffer_async_read
* completion) then there is a possibility that another thread of
* control could lock one of the buffers after it has completed
* but while some of the other buffers have not completed. This
* locked buffer would confuse end_buffer_async_read() into not unlocking
* the page. So the absence of BH_Async_Read tells end_buffer_async_read()
* that this buffer is not under async I/O.
*
* The page comes unlocked when it has no locked buffer_async buffers
* left.
*
* PageLocked prevents anyone starting new async I/O reads any of
* the buffers.
*
* PageWriteback is used to prevent simultaneous writeout of the same
* page.
*
* PageLocked prevents anyone from starting writeback of a page which is
* under read I/O (PageWriteback is only ever set against a locked page).
*/
static void mark_buffer_async_read(struct buffer_head *bh)
{
bh->b_end_io = end_buffer_async_read_io;
set_buffer_async_read(bh);
}
static void mark_buffer_async_write_endio(struct buffer_head *bh,
bh_end_io_t *handler)
{
bh->b_end_io = handler;
set_buffer_async_write(bh);
}
void mark_buffer_async_write(struct buffer_head *bh)
{
mark_buffer_async_write_endio(bh, end_buffer_async_write);
}
EXPORT_SYMBOL(mark_buffer_async_write);
/*
* fs/buffer.c contains helper functions for buffer-backed address space's
* fsync functions. A common requirement for buffer-based filesystems is
* that certain data from the backing blockdev needs to be written out for
* a successful fsync(). For example, ext2 indirect blocks need to be
* written back and waited upon before fsync() returns.
*
* The functions mark_buffer_inode_dirty(), fsync_inode_buffers(),
* inode_has_buffers() and invalidate_inode_buffers() are provided for the
* management of a list of dependent buffers at ->i_mapping->private_list.
*
* Locking is a little subtle: try_to_free_buffers() will remove buffers
* from their controlling inode's queue when they are being freed. But
* try_to_free_buffers() will be operating against the *blockdev* mapping
* at the time, not against the S_ISREG file which depends on those buffers.
* So the locking for private_list is via the private_lock in the address_space
* which backs the buffers. Which is different from the address_space
* against which the buffers are listed. So for a particular address_space,
* mapping->private_lock does *not* protect mapping->private_list! In fact,
* mapping->private_list will always be protected by the backing blockdev's
* ->private_lock.
*
* Which introduces a requirement: all buffers on an address_space's
* ->private_list must be from the same address_space: the blockdev's.
*
* address_spaces which do not place buffers at ->private_list via these
* utility functions are free to use private_lock and private_list for
* whatever they want. The only requirement is that list_empty(private_list)
* be true at clear_inode() time.
*
* FIXME: clear_inode should not call invalidate_inode_buffers(). The
* filesystems should do that. invalidate_inode_buffers() should just go
* BUG_ON(!list_empty).
*
* FIXME: mark_buffer_dirty_inode() is a data-plane operation. It should
* take an address_space, not an inode. And it should be called
* mark_buffer_dirty_fsync() to clearly define why those buffers are being
* queued up.
*
* FIXME: mark_buffer_dirty_inode() doesn't need to add the buffer to the
* list if it is already on a list. Because if the buffer is on a list,
* it *must* already be on the right one. If not, the filesystem is being
* silly. This will save a ton of locking. But first we have to ensure
* that buffers are taken *off* the old inode's list when they are freed
* (presumably in truncate). That requires careful auditing of all
* filesystems (do it inside bforget()). It could also be done by bringing
* b_inode back.
*/
/*
* The buffer's backing address_space's private_lock must be held
*/
static void __remove_assoc_queue(struct buffer_head *bh)
{
list_del_init(&bh->b_assoc_buffers);
WARN_ON(!bh->b_assoc_map);
bh->b_assoc_map = NULL;
}
int inode_has_buffers(struct inode *inode)
{
return !list_empty(&inode->i_data.private_list);
}
/*
* osync is designed to support O_SYNC io. It waits synchronously for
* all already-submitted IO to complete, but does not queue any new
* writes to the disk.
*
* To do O_SYNC writes, just queue the buffer writes with write_dirty_buffer
* as you dirty the buffers, and then use osync_inode_buffers to wait for
* completion. Any other dirty buffers which are not yet queued for
* write will not be flushed to disk by the osync.
*/
static int osync_buffers_list(spinlock_t *lock, struct list_head *list)
{
struct buffer_head *bh;
struct list_head *p;
int err = 0;
spin_lock(lock);
repeat:
list_for_each_prev(p, list) {
bh = BH_ENTRY(p);
if (buffer_locked(bh)) {
get_bh(bh);
spin_unlock(lock);
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
err = -EIO;
brelse(bh);
spin_lock(lock);
goto repeat;
}
}
spin_unlock(lock);
return err;
}
/**
* sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers
* @mapping: the mapping which wants those buffers written
*
* Starts I/O against the buffers at mapping->private_list, and waits upon
* that I/O.
*
* Basically, this is a convenience function for fsync().
* @mapping is a file or directory which needs those buffers to be written for
* a successful fsync().
*/
int sync_mapping_buffers(struct address_space *mapping)
{
struct address_space *buffer_mapping = mapping->private_data;
if (buffer_mapping == NULL || list_empty(&mapping->private_list))
return 0;
return fsync_buffers_list(&buffer_mapping->private_lock,
&mapping->private_list);
}
EXPORT_SYMBOL(sync_mapping_buffers);
/**
* generic_buffers_fsync_noflush - generic buffer fsync implementation
* for simple filesystems with no inode lock
*
* @file: file to synchronize
* @start: start offset in bytes
* @end: end offset in bytes (inclusive)
* @datasync: only synchronize essential metadata if true
*
* This is a generic implementation of the fsync method for simple
* filesystems which track all non-inode metadata in the buffers list
* hanging off the address_space structure.
*/
int generic_buffers_fsync_noflush(struct file *file, loff_t start, loff_t end,
bool datasync)
{
struct inode *inode = file->f_mapping->host;
int err;
int ret;
err = file_write_and_wait_range(file, start, end);
if (err)
return err;
ret = sync_mapping_buffers(inode->i_mapping);
if (!(inode->i_state & I_DIRTY_ALL))
goto out;
if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
goto out;
err = sync_inode_metadata(inode, 1);
if (ret == 0)
ret = err;
out:
/* check and advance again to catch errors after syncing out buffers */
err = file_check_and_advance_wb_err(file);
if (ret == 0)
ret = err;
return ret;
}
EXPORT_SYMBOL(generic_buffers_fsync_noflush);
/**
* generic_buffers_fsync - generic buffer fsync implementation
* for simple filesystems with no inode lock
*
* @file: file to synchronize
* @start: start offset in bytes
* @end: end offset in bytes (inclusive)
* @datasync: only synchronize essential metadata if true
*
* This is a generic implementation of the fsync method for simple
* filesystems which track all non-inode metadata in the buffers list
* hanging off the address_space structure. This also makes sure that
* a device cache flush operation is called at the end.
*/
int generic_buffers_fsync(struct file *file, loff_t start, loff_t end,
bool datasync)
{
struct inode *inode = file->f_mapping->host;
int ret;
ret = generic_buffers_fsync_noflush(file, start, end, datasync);
if (!ret)
ret = blkdev_issue_flush(inode->i_sb->s_bdev);
return ret;
}
EXPORT_SYMBOL(generic_buffers_fsync);
/*
* Called when we've recently written block `bblock', and it is known that
* `bblock' was for a buffer_boundary() buffer. This means that the block at
* `bblock + 1' is probably a dirty indirect block. Hunt it down and, if it's
* dirty, schedule it for IO. So that indirects merge nicely with their data.
*/
void write_boundary_block(struct block_device *bdev,
sector_t bblock, unsigned blocksize)
{
struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize);
if (bh) {
if (buffer_dirty(bh))
write_dirty_buffer(bh, 0);
put_bh(bh);
}
}
void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode)
{
struct address_space *mapping = inode->i_mapping;
struct address_space *buffer_mapping = bh->b_folio->mapping;
mark_buffer_dirty(bh);
if (!mapping->private_data) {
mapping->private_data = buffer_mapping;
} else {
BUG_ON(mapping->private_data != buffer_mapping);
}
if (!bh->b_assoc_map) {
spin_lock(&buffer_mapping->private_lock);
list_move_tail(&bh->b_assoc_buffers,
&mapping->private_list);
bh->b_assoc_map = mapping;
spin_unlock(&buffer_mapping->private_lock);
}
}
EXPORT_SYMBOL(mark_buffer_dirty_inode);
/*
* Add a page to the dirty page list.
*
* It is a sad fact of life that this function is called from several places
* deeply under spinlocking. It may not sleep.
*
* If the page has buffers, the uptodate buffers are set dirty, to preserve
* dirty-state coherency between the page and the buffers. It the page does
* not have buffers then when they are later attached they will all be set
* dirty.
*
* The buffers are dirtied before the page is dirtied. There's a small race
* window in which a writepage caller may see the page cleanness but not the
* buffer dirtiness. That's fine. If this code were to set the page dirty
* before the buffers, a concurrent writepage caller could clear the page dirty
* bit, see a bunch of clean buffers and we'd end up with dirty buffers/clean
* page on the dirty page list.
*
* We use private_lock to lock against try_to_free_buffers while using the
* page's buffer list. Also use this to protect against clean buffers being
* added to the page after it was set dirty.
*
* FIXME: may need to call ->reservepage here as well. That's rather up to the
* address_space though.
*/
bool block_dirty_folio(struct address_space *mapping, struct folio *folio)
{
struct buffer_head *head;
bool newly_dirty;
spin_lock(&mapping->private_lock);
head = folio_buffers(folio);
if (head) {
struct buffer_head *bh = head;
do {
set_buffer_dirty(bh);
bh = bh->b_this_page;
} while (bh != head);
}
/*
* Lock out page's memcg migration to keep PageDirty
* synchronized with per-memcg dirty page counters.
*/
folio_memcg_lock(folio);
newly_dirty = !folio_test_set_dirty(folio);
spin_unlock(&mapping->private_lock);
if (newly_dirty)
__folio_mark_dirty(folio, mapping, 1);
folio_memcg_unlock(folio);
if (newly_dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
return newly_dirty;
}
EXPORT_SYMBOL(block_dirty_folio);
/*
* Write out and wait upon a list of buffers.
*
* We have conflicting pressures: we want to make sure that all
* initially dirty buffers get waited on, but that any subsequently
* dirtied buffers don't. After all, we don't want fsync to last
* forever if somebody is actively writing to the file.
*
* Do this in two main stages: first we copy dirty buffers to a
* temporary inode list, queueing the writes as we go. Then we clean
* up, waiting for those writes to complete.
*
* During this second stage, any subsequent updates to the file may end
* up refiling the buffer on the original inode's dirty list again, so
* there is a chance we will end up with a buffer queued for write but
* not yet completed on that list. So, as a final cleanup we go through
* the osync code to catch these locked, dirty buffers without requeuing
* any newly dirty buffers for write.
*/
static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
{
struct buffer_head *bh;
struct list_head tmp;
struct address_space *mapping;
int err = 0, err2;
struct blk_plug plug;
INIT_LIST_HEAD(&tmp);
blk_start_plug(&plug);
spin_lock(lock);
while (!list_empty(list)) {
bh = BH_ENTRY(list->next);
mapping = bh->b_assoc_map;
__remove_assoc_queue(bh);
/* Avoid race with mark_buffer_dirty_inode() which does
* a lockless check and we rely on seeing the dirty bit */
smp_mb();
if (buffer_dirty(bh) || buffer_locked(bh)) {
list_add(&bh->b_assoc_buffers, &tmp);
bh->b_assoc_map = mapping;
if (buffer_dirty(bh)) {
get_bh(bh);
spin_unlock(lock);
/*
* Ensure any pending I/O completes so that
* write_dirty_buffer() actually writes the
* current contents - it is a noop if I/O is
* still in flight on potentially older
* contents.
*/
write_dirty_buffer(bh, REQ_SYNC);
/*
* Kick off IO for the previous mapping. Note
* that we will not run the very last mapping,
* wait_on_buffer() will do that for us
* through sync_buffer().
*/
brelse(bh);
spin_lock(lock);
}
}
}
spin_unlock(lock);
blk_finish_plug(&plug);
spin_lock(lock);
while (!list_empty(&tmp)) {
bh = BH_ENTRY(tmp.prev);
get_bh(bh);
mapping = bh->b_assoc_map;
__remove_assoc_queue(bh);
/* Avoid race with mark_buffer_dirty_inode() which does
* a lockless check and we rely on seeing the dirty bit */
smp_mb();
if (buffer_dirty(bh)) {
list_add(&bh->b_assoc_buffers,
&mapping->private_list);
bh->b_assoc_map = mapping;
}
spin_unlock(lock);
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
err = -EIO;
brelse(bh);
spin_lock(lock);
}
spin_unlock(lock);
err2 = osync_buffers_list(lock, list);
if (err)
return err;
else
return err2;
}
/*
* Invalidate any and all dirty buffers on a given inode. We are
* probably unmounting the fs, but that doesn't mean we have already
* done a sync(). Just drop the buffers from the inode list.
*
* NOTE: we take the inode's blockdev's mapping's private_lock. Which
* assumes that all the buffers are against the blockdev. Not true
* for reiserfs.
*/
void invalidate_inode_buffers(struct inode *inode)
{
if (inode_has_buffers(inode)) {
struct address_space *mapping = &inode->i_data;
struct list_head *list = &mapping->private_list;
struct address_space *buffer_mapping = mapping->private_data;
spin_lock(&buffer_mapping->private_lock);
while (!list_empty(list))
__remove_assoc_queue(BH_ENTRY(list->next));
spin_unlock(&buffer_mapping->private_lock);
}
}
EXPORT_SYMBOL(invalidate_inode_buffers);
/*
* Remove any clean buffers from the inode's buffer list. This is called
* when we're trying to free the inode itself. Those buffers can pin it.
*
* Returns true if all buffers were removed.
*/
int remove_inode_buffers(struct inode *inode)
{
int ret = 1;
if (inode_has_buffers(inode)) {
struct address_space *mapping = &inode->i_data;
struct list_head *list = &mapping->private_list;
struct address_space *buffer_mapping = mapping->private_data;
spin_lock(&buffer_mapping->private_lock);
while (!list_empty(list)) {
struct buffer_head *bh = BH_ENTRY(list->next);
if (buffer_dirty(bh)) {
ret = 0;
break;
}
__remove_assoc_queue(bh);
}
spin_unlock(&buffer_mapping->private_lock);
}
return ret;
}
/*
* Create the appropriate buffers when given a folio for data area and
* the size of each buffer.. Use the bh->b_this_page linked list to
* follow the buffers created. Return NULL if unable to create more
* buffers.
*
* The retry flag is used to differentiate async IO (paging, swapping)
* which may not fail from ordinary buffer allocations.
*/
struct buffer_head *folio_alloc_buffers(struct folio *folio, unsigned long size,
bool retry)
{
struct buffer_head *bh, *head;
gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT;
long offset;
struct mem_cgroup *memcg, *old_memcg;
if (retry)
gfp |= __GFP_NOFAIL;
/* The folio lock pins the memcg */
memcg = folio_memcg(folio);
old_memcg = set_active_memcg(memcg);
head = NULL;
offset = folio_size(folio);
while ((offset -= size) >= 0) {
bh = alloc_buffer_head(gfp);
if (!bh)
goto no_grow;
bh->b_this_page = head;
bh->b_blocknr = -1;
head = bh;
bh->b_size = size;
/* Link the buffer to its folio */
folio_set_bh(bh, folio, offset);
}
out:
set_active_memcg(old_memcg);
return head;
/*
* In case anything failed, we just free everything we got.
*/
no_grow:
if (head) {
do {
bh = head;
head = head->b_this_page;
free_buffer_head(bh);
} while (head);
}
goto out;
}
EXPORT_SYMBOL_GPL(folio_alloc_buffers);
struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
bool retry)
{
return folio_alloc_buffers(page_folio(page), size, retry);
}
EXPORT_SYMBOL_GPL(alloc_page_buffers);
static inline void link_dev_buffers(struct folio *folio,
struct buffer_head *head)
{
struct buffer_head *bh, *tail;
bh = head;
do {
tail = bh;
bh = bh->b_this_page;
} while (bh);
tail->b_this_page = head;
folio_attach_private(folio, head);
}
static sector_t blkdev_max_block(struct block_device *bdev, unsigned int size)
{
sector_t retval = ~((sector_t)0);
loff_t sz = bdev_nr_bytes(bdev);
if (sz) {
unsigned int sizebits = blksize_bits(size);
retval = (sz >> sizebits);
}
return retval;
}
/*
* Initialise the state of a blockdev folio's buffers.
*/
static sector_t folio_init_buffers(struct folio *folio,
struct block_device *bdev, sector_t block, int size)
{
struct buffer_head *head = folio_buffers(folio);
struct buffer_head *bh = head;
bool uptodate = folio_test_uptodate(folio);
sector_t end_block = blkdev_max_block(bdev, size);
do {
if (!buffer_mapped(bh)) {
bh->b_end_io = NULL;
bh->b_private = NULL;
bh->b_bdev = bdev;
bh->b_blocknr = block;
if (uptodate)
set_buffer_uptodate(bh);
if (block < end_block)
set_buffer_mapped(bh);
}
block++;
bh = bh->b_this_page;
} while (bh != head);
/*
* Caller needs to validate requested block against end of device.
*/
return end_block;
}
/*
* Create the page-cache page that contains the requested block.
*
* This is used purely for blockdev mappings.
*/
static int
grow_dev_page(struct block_device *bdev, sector_t block,
pgoff_t index, int size, int sizebits, gfp_t gfp)
{
struct inode *inode = bdev->bd_inode;
struct folio *folio;
struct buffer_head *bh;
sector_t end_block;
int ret = 0;
gfp_t gfp_mask;
gfp_mask = mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS) | gfp;
/*
* XXX: __getblk_slow() can not really deal with failure and
* will endlessly loop on improvised global reclaim. Prefer
* looping in the allocator rather than here, at least that
* code knows what it's doing.
*/
gfp_mask |= __GFP_NOFAIL;
folio = __filemap_get_folio(inode->i_mapping, index,
FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp_mask);
bh = folio_buffers(folio);
if (bh) {
if (bh->b_size == size) {
end_block = folio_init_buffers(folio, bdev,
(sector_t)index << sizebits, size);
goto done;
}
if (!try_to_free_buffers(folio))
goto failed;
}
bh = folio_alloc_buffers(folio, size, true);
/*
* Link the folio to the buffers and initialise them. Take the
* lock to be atomic wrt __find_get_block(), which does not
* run under the folio lock.
*/
spin_lock(&inode->i_mapping->private_lock);
link_dev_buffers(folio, bh);
end_block = folio_init_buffers(folio, bdev,
(sector_t)index << sizebits, size);
spin_unlock(&inode->i_mapping->private_lock);
done:
ret = (block < end_block) ? 1 : -ENXIO;
failed:
folio_unlock(folio);
folio_put(folio);
return ret;
}
/*
* Create buffers for the specified block device block's page. If
* that page was dirty, the buffers are set dirty also.
*/
static int
grow_buffers(struct block_device *bdev, sector_t block, int size, gfp_t gfp)
{
pgoff_t index;
int sizebits;
sizebits = PAGE_SHIFT - __ffs(size);
index = block >> sizebits;
/*
* Check for a block which wants to lie outside our maximum possible
* pagecache index. (this comparison is done using sector_t types).
*/
if (unlikely(index != block >> sizebits)) {
printk(KERN_ERR "%s: requested out-of-range block %llu for "
"device %pg\n",
__func__, (unsigned long long)block,
bdev);
return -EIO;
}
/* Create a page with the proper size buffers.. */
return grow_dev_page(bdev, block, index, size, sizebits, gfp);
}
static struct buffer_head *
__getblk_slow(struct block_device *bdev, sector_t block,
unsigned size, gfp_t gfp)
{
/* Size must be multiple of hard sectorsize */
if (unlikely(size & (bdev_logical_block_size(bdev)-1) ||
(size < 512 || size > PAGE_SIZE))) {
printk(KERN_ERR "getblk(): invalid block size %d requested\n",
size);
printk(KERN_ERR "logical block size: %d\n",
bdev_logical_block_size(bdev));
dump_stack();
return NULL;
}
for (;;) {
struct buffer_head *bh;
int ret;
bh = __find_get_block(bdev, block, size);
if (bh)
return bh;
ret = grow_buffers(bdev, block, size, gfp);
if (ret < 0)
return NULL;
}
}
/*
* The relationship between dirty buffers and dirty pages:
*
* Whenever a page has any dirty buffers, the page's dirty bit is set, and
* the page is tagged dirty in the page cache.
*
* At all times, the dirtiness of the buffers represents the dirtiness of
* subsections of the page. If the page has buffers, the page dirty bit is
* merely a hint about the true dirty state.
*
* When a page is set dirty in its entirety, all its buffers are marked dirty
* (if the page has buffers).
*
* When a buffer is marked dirty, its page is dirtied, but the page's other
* buffers are not.
*
* Also. When blockdev buffers are explicitly read with bread(), they
* individually become uptodate. But their backing page remains not
* uptodate - even if all of its buffers are uptodate. A subsequent
* block_read_full_folio() against that folio will discover all the uptodate
* buffers, will set the folio uptodate and will perform no I/O.
*/
/**
* mark_buffer_dirty - mark a buffer_head as needing writeout
* @bh: the buffer_head to mark dirty
*
* mark_buffer_dirty() will set the dirty bit against the buffer, then set
* its backing page dirty, then tag the page as dirty in the page cache
* and then attach the address_space's inode to its superblock's dirty
* inode list.
*
* mark_buffer_dirty() is atomic. It takes bh->b_folio->mapping->private_lock,
* i_pages lock and mapping->host->i_lock.
*/
void mark_buffer_dirty(struct buffer_head *bh)
{
WARN_ON_ONCE(!buffer_uptodate(bh));
trace_block_dirty_buffer(bh);
/*
* Very *carefully* optimize the it-is-already-dirty case.
*
* Don't let the final "is it dirty" escape to before we
* perhaps modified the buffer.
*/
if (buffer_dirty(bh)) {
smp_mb();
if (buffer_dirty(bh))
return;
}
if (!test_set_buffer_dirty(bh)) {
struct folio *folio = bh->b_folio;
struct address_space *mapping = NULL;
folio_memcg_lock(folio);
if (!folio_test_set_dirty(folio)) {
mapping = folio->mapping;
if (mapping)
__folio_mark_dirty(folio, mapping, 0);
}
folio_memcg_unlock(folio);
if (mapping)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
}
}
EXPORT_SYMBOL(mark_buffer_dirty);
void mark_buffer_write_io_error(struct buffer_head *bh)
{
set_buffer_write_io_error(bh);
/* FIXME: do we need to set this in both places? */
if (bh->b_folio && bh->b_folio->mapping)
mapping_set_error(bh->b_folio->mapping, -EIO);
if (bh->b_assoc_map) {
mapping_set_error(bh->b_assoc_map, -EIO);
errseq_set(&bh->b_assoc_map->host->i_sb->s_wb_err, -EIO);
}
}
EXPORT_SYMBOL(mark_buffer_write_io_error);
/*
* Decrement a buffer_head's reference count. If all buffers against a page
* have zero reference count, are clean and unlocked, and if the page is clean
* and unlocked then try_to_free_buffers() may strip the buffers from the page
* in preparation for freeing it (sometimes, rarely, buffers are removed from
* a page but it ends up not being freed, and buffers may later be reattached).
*/
void __brelse(struct buffer_head * buf)
{
if (atomic_read(&buf->b_count)) {
put_bh(buf);
return;
}
WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n");
}
EXPORT_SYMBOL(__brelse);
/*
* bforget() is like brelse(), except it discards any
* potentially dirty data.
*/
void __bforget(struct buffer_head *bh)
{
clear_buffer_dirty(bh);
if (bh->b_assoc_map) {
struct address_space *buffer_mapping = bh->b_folio->mapping;
spin_lock(&buffer_mapping->private_lock);
list_del_init(&bh->b_assoc_buffers);
bh->b_assoc_map = NULL;
spin_unlock(&buffer_mapping->private_lock);
}
__brelse(bh);
}
EXPORT_SYMBOL(__bforget);
static struct buffer_head *__bread_slow(struct buffer_head *bh)
{
lock_buffer(bh);
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
return bh;
} else {
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(REQ_OP_READ, bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh))
return bh;
}
brelse(bh);
return NULL;
}
/*
* Per-cpu buffer LRU implementation. To reduce the cost of __find_get_block().
* The bhs[] array is sorted - newest buffer is at bhs[0]. Buffers have their
* refcount elevated by one when they're in an LRU. A buffer can only appear
* once in a particular CPU's LRU. A single buffer can be present in multiple
* CPU's LRUs at the same time.
*
* This is a transparent caching front-end to sb_bread(), sb_getblk() and
* sb_find_get_block().
*
* The LRUs themselves only need locking against invalidate_bh_lrus. We use
* a local interrupt disable for that.
*/
#define BH_LRU_SIZE 16
struct bh_lru {
struct buffer_head *bhs[BH_LRU_SIZE];
};
static DEFINE_PER_CPU(struct bh_lru, bh_lrus) = {{ NULL }};
#ifdef CONFIG_SMP
#define bh_lru_lock() local_irq_disable()
#define bh_lru_unlock() local_irq_enable()
#else
#define bh_lru_lock() preempt_disable()
#define bh_lru_unlock() preempt_enable()
#endif
static inline void check_irqs_on(void)
{
#ifdef irqs_disabled
BUG_ON(irqs_disabled());
#endif
}
/*
* Install a buffer_head into this cpu's LRU. If not already in the LRU, it is
* inserted at the front, and the buffer_head at the back if any is evicted.
* Or, if already in the LRU it is moved to the front.
*/
static void bh_lru_install(struct buffer_head *bh)
{
struct buffer_head *evictee = bh;
struct bh_lru *b;
int i;
check_irqs_on();
bh_lru_lock();
/*
* the refcount of buffer_head in bh_lru prevents dropping the
* attached page(i.e., try_to_free_buffers) so it could cause
* failing page migration.
* Skip putting upcoming bh into bh_lru until migration is done.
*/
if (lru_cache_disabled() || cpu_is_isolated(smp_processor_id())) {
bh_lru_unlock();
return;
}
b = this_cpu_ptr(&bh_lrus);
for (i = 0; i < BH_LRU_SIZE; i++) {
swap(evictee, b->bhs[i]);
if (evictee == bh) {
bh_lru_unlock();
return;
}
}
get_bh(bh);
bh_lru_unlock();
brelse(evictee);
}
/*
* Look up the bh in this cpu's LRU. If it's there, move it to the head.
*/
static struct buffer_head *
lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size)
{
struct buffer_head *ret = NULL;
unsigned int i;
check_irqs_on();
bh_lru_lock();
if (cpu_is_isolated(smp_processor_id())) {
bh_lru_unlock();
return NULL;
}
for (i = 0; i < BH_LRU_SIZE; i++) {
struct buffer_head *bh = __this_cpu_read(bh_lrus.bhs[i]);
if (bh && bh->b_blocknr == block && bh->b_bdev == bdev &&
bh->b_size == size) {
if (i) {
while (i) {
__this_cpu_write(bh_lrus.bhs[i],
__this_cpu_read(bh_lrus.bhs[i - 1]));
i--;
}
__this_cpu_write(bh_lrus.bhs[0], bh);
}
get_bh(bh);
ret = bh;
break;
}
}
bh_lru_unlock();
return ret;
}
/*
* Perform a pagecache lookup for the matching buffer. If it's there, refresh
* it in the LRU and mark it as accessed. If it is not present then return
* NULL
*/
struct buffer_head *
__find_get_block(struct block_device *bdev, sector_t block, unsigned size)
{
struct buffer_head *bh = lookup_bh_lru(bdev, block, size);
if (bh == NULL) {
/* __find_get_block_slow will mark the page accessed */
bh = __find_get_block_slow(bdev, block);
if (bh)
bh_lru_install(bh);
} else
touch_buffer(bh);
return bh;
}
EXPORT_SYMBOL(__find_get_block);
/*
* __getblk_gfp() will locate (and, if necessary, create) the buffer_head
* which corresponds to the passed block_device, block and size. The
* returned buffer has its reference count incremented.
*
* __getblk_gfp() will lock up the machine if grow_dev_page's
* try_to_free_buffers() attempt is failing. FIXME, perhaps?
*/
struct buffer_head *
__getblk_gfp(struct block_device *bdev, sector_t block,
unsigned size, gfp_t gfp)
{
struct buffer_head *bh = __find_get_block(bdev, block, size);
might_sleep();
if (bh == NULL)
bh = __getblk_slow(bdev, block, size, gfp);
return bh;
}
EXPORT_SYMBOL(__getblk_gfp);
/*
* Do async read-ahead on a buffer..
*/
void __breadahead(struct block_device *bdev, sector_t block, unsigned size)
{
struct buffer_head *bh = __getblk(bdev, block, size);
if (likely(bh)) {
bh_readahead(bh, REQ_RAHEAD);
brelse(bh);
}
}
EXPORT_SYMBOL(__breadahead);
/**
* __bread_gfp() - reads a specified block and returns the bh
* @bdev: the block_device to read from
* @block: number of block
* @size: size (in bytes) to read
* @gfp: page allocation flag
*
* Reads a specified block, and returns buffer head that contains it.
* The page cache can be allocated from non-movable area
* not to prevent page migration if you set gfp to zero.
* It returns NULL if the block was unreadable.
*/
struct buffer_head *
__bread_gfp(struct block_device *bdev, sector_t block,
unsigned size, gfp_t gfp)
{
struct buffer_head *bh = __getblk_gfp(bdev, block, size, gfp);
if (likely(bh) && !buffer_uptodate(bh))
bh = __bread_slow(bh);
return bh;
}
EXPORT_SYMBOL(__bread_gfp);
static void __invalidate_bh_lrus(struct bh_lru *b)
{
int i;
for (i = 0; i < BH_LRU_SIZE; i++) {
brelse(b->bhs[i]);
b->bhs[i] = NULL;
}
}
/*
* invalidate_bh_lrus() is called rarely - but not only at unmount.
* This doesn't race because it runs in each cpu either in irq
* or with preempt disabled.
*/
static void invalidate_bh_lru(void *arg)
{
struct bh_lru *b = &get_cpu_var(bh_lrus);
__invalidate_bh_lrus(b);
put_cpu_var(bh_lrus);
}
bool has_bh_in_lru(int cpu, void *dummy)
{
struct bh_lru *b = per_cpu_ptr(&bh_lrus, cpu);
int i;
for (i = 0; i < BH_LRU_SIZE; i++) {
if (b->bhs[i])
return true;
}
return false;
}
void invalidate_bh_lrus(void)
{
on_each_cpu_cond(has_bh_in_lru, invalidate_bh_lru, NULL, 1);
}
EXPORT_SYMBOL_GPL(invalidate_bh_lrus);
/*
* It's called from workqueue context so we need a bh_lru_lock to close
* the race with preemption/irq.
*/
void invalidate_bh_lrus_cpu(void)
{
struct bh_lru *b;
bh_lru_lock();
b = this_cpu_ptr(&bh_lrus);
__invalidate_bh_lrus(b);
bh_lru_unlock();
}
void folio_set_bh(struct buffer_head *bh, struct folio *folio,
unsigned long offset)
{
bh->b_folio = folio;
BUG_ON(offset >= folio_size(folio));
if (folio_test_highmem(folio))
/*
* This catches illegal uses and preserves the offset:
*/
bh->b_data = (char *)(0 + offset);
else
bh->b_data = folio_address(folio) + offset;
}
EXPORT_SYMBOL(folio_set_bh);
/*
* Called when truncating a buffer on a page completely.
*/
/* Bits that are cleared during an invalidate */
#define BUFFER_FLAGS_DISCARD \
(1 << BH_Mapped | 1 << BH_New | 1 << BH_Req | \
1 << BH_Delay | 1 << BH_Unwritten)
static void discard_buffer(struct buffer_head * bh)
{
unsigned long b_state;
lock_buffer(bh);
clear_buffer_dirty(bh);
bh->b_bdev = NULL;
b_state = READ_ONCE(bh->b_state);
do {
} while (!try_cmpxchg(&bh->b_state, &b_state,
b_state & ~BUFFER_FLAGS_DISCARD));
unlock_buffer(bh);
}
/**
* block_invalidate_folio - Invalidate part or all of a buffer-backed folio.
* @folio: The folio which is affected.
* @offset: start of the range to invalidate
* @length: length of the range to invalidate
*
* block_invalidate_folio() is called when all or part of the folio has been
* invalidated by a truncate operation.
*
* block_invalidate_folio() does not have to release all buffers, but it must
* ensure that no dirty buffer is left outside @offset and that no I/O
* is underway against any of the blocks which are outside the truncation
* point. Because the caller is about to free (and possibly reuse) those
* blocks on-disk.
*/
void block_invalidate_folio(struct folio *folio, size_t offset, size_t length)
{
struct buffer_head *head, *bh, *next;
size_t curr_off = 0;
size_t stop = length + offset;
BUG_ON(!folio_test_locked(folio));
/*
* Check for overflow
*/
BUG_ON(stop > folio_size(folio) || stop < length);
head = folio_buffers(folio);
if (!head)
return;
bh = head;
do {
size_t next_off = curr_off + bh->b_size;
next = bh->b_this_page;
/*
* Are we still fully in range ?
*/
if (next_off > stop)
goto out;
/*
* is this block fully invalidated?
*/
if (offset <= curr_off)
discard_buffer(bh);
curr_off = next_off;
bh = next;
} while (bh != head);
/*
* We release buffers only if the entire folio is being invalidated.
* The get_block cached value has been unconditionally invalidated,
* so real IO is not possible anymore.
*/
if (length == folio_size(folio))
filemap_release_folio(folio, 0);
out:
return;
}
EXPORT_SYMBOL(block_invalidate_folio);
/*
* We attach and possibly dirty the buffers atomically wrt
* block_dirty_folio() via private_lock. try_to_free_buffers
* is already excluded via the folio lock.
*/
void folio_create_empty_buffers(struct folio *folio, unsigned long blocksize,
unsigned long b_state)
{
struct buffer_head *bh, *head, *tail;
head = folio_alloc_buffers(folio, blocksize, true);
bh = head;
do {
bh->b_state |= b_state;
tail = bh;
bh = bh->b_this_page;
} while (bh);
tail->b_this_page = head;
spin_lock(&folio->mapping->private_lock);
if (folio_test_uptodate(folio) || folio_test_dirty(folio)) {
bh = head;
do {
if (folio_test_dirty(folio))
set_buffer_dirty(bh);
if (folio_test_uptodate(folio))
set_buffer_uptodate(bh);
bh = bh->b_this_page;
} while (bh != head);
}
folio_attach_private(folio, head);
spin_unlock(&folio->mapping->private_lock);
}
EXPORT_SYMBOL(folio_create_empty_buffers);
void create_empty_buffers(struct page *page,
unsigned long blocksize, unsigned long b_state)
{
folio_create_empty_buffers(page_folio(page), blocksize, b_state);
}
EXPORT_SYMBOL(create_empty_buffers);
/**
* clean_bdev_aliases: clean a range of buffers in block device
* @bdev: Block device to clean buffers in
* @block: Start of a range of blocks to clean
* @len: Number of blocks to clean
*
* We are taking a range of blocks for data and we don't want writeback of any
* buffer-cache aliases starting from return from this function and until the
* moment when something will explicitly mark the buffer dirty (hopefully that
* will not happen until we will free that block ;-) We don't even need to mark
* it not-uptodate - nobody can expect anything from a newly allocated buffer
* anyway. We used to use unmap_buffer() for such invalidation, but that was
* wrong. We definitely don't want to mark the alias unmapped, for example - it
* would confuse anyone who might pick it with bread() afterwards...
*
* Also.. Note that bforget() doesn't lock the buffer. So there can be
* writeout I/O going on against recently-freed buffers. We don't wait on that
* I/O in bforget() - it's more efficient to wait on the I/O only if we really
* need to. That happens here.
*/
void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len)
{
struct inode *bd_inode = bdev->bd_inode;
struct address_space *bd_mapping = bd_inode->i_mapping;
struct folio_batch fbatch;
pgoff_t index = block >> (PAGE_SHIFT - bd_inode->i_blkbits);
pgoff_t end;
int i, count;
struct buffer_head *bh;
struct buffer_head *head;
end = (block + len - 1) >> (PAGE_SHIFT - bd_inode->i_blkbits);
folio_batch_init(&fbatch);
while (filemap_get_folios(bd_mapping, &index, end, &fbatch)) {
count = folio_batch_count(&fbatch);
for (i = 0; i < count; i++) {
struct folio *folio = fbatch.folios[i];
if (!folio_buffers(folio))
continue;
/*
* We use folio lock instead of bd_mapping->private_lock
* to pin buffers here since we can afford to sleep and
* it scales better than a global spinlock lock.
*/
folio_lock(folio);
/* Recheck when the folio is locked which pins bhs */
head = folio_buffers(folio);
if (!head)
goto unlock_page;
bh = head;
do {
if (!buffer_mapped(bh) || (bh->b_blocknr < block))
goto next;
if (bh->b_blocknr >= block + len)
break;
clear_buffer_dirty(bh);
wait_on_buffer(bh);
clear_buffer_req(bh);
next:
bh = bh->b_this_page;
} while (bh != head);
unlock_page:
folio_unlock(folio);
}
folio_batch_release(&fbatch);
cond_resched();
/* End of range already reached? */
if (index > end || !index)
break;
}
}
EXPORT_SYMBOL(clean_bdev_aliases);
/*
* Size is a power-of-two in the range 512..PAGE_SIZE,
* and the case we care about most is PAGE_SIZE.
*
* So this *could* possibly be written with those
* constraints in mind (relevant mostly if some
* architecture has a slow bit-scan instruction)
*/
static inline int block_size_bits(unsigned int blocksize)
{
return ilog2(blocksize);
}
static struct buffer_head *folio_create_buffers(struct folio *folio,
struct inode *inode,
unsigned int b_state)
{
BUG_ON(!folio_test_locked(folio));
if (!folio_buffers(folio))
folio_create_empty_buffers(folio,
1 << READ_ONCE(inode->i_blkbits),
b_state);
return folio_buffers(folio);
}
/*
* NOTE! All mapped/uptodate combinations are valid:
*
* Mapped Uptodate Meaning
*
* No No "unknown" - must do get_block()
* No Yes "hole" - zero-filled
* Yes No "allocated" - allocated on disk, not read in
* Yes Yes "valid" - allocated and up-to-date in memory.
*
* "Dirty" is valid only with the last case (mapped+uptodate).
*/
/*
* While block_write_full_page is writing back the dirty buffers under
* the page lock, whoever dirtied the buffers may decide to clean them
* again at any time. We handle that by only looking at the buffer
* state inside lock_buffer().
*
* If block_write_full_page() is called for regular writeback
* (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a
* locked buffer. This only can happen if someone has written the buffer
* directly, with submit_bh(). At the address_space level PageWriteback
* prevents this contention from occurring.
*
* If block_write_full_page() is called with wbc->sync_mode ==
* WB_SYNC_ALL, the writes are posted using REQ_SYNC; this
* causes the writes to be flagged as synchronous writes.
*/
int __block_write_full_folio(struct inode *inode, struct folio *folio,
get_block_t *get_block, struct writeback_control *wbc,
bh_end_io_t *handler)
{
int err;
sector_t block;
sector_t last_block;
struct buffer_head *bh, *head;
unsigned int blocksize, bbits;
int nr_underway = 0;
blk_opf_t write_flags = wbc_to_write_flags(wbc);
head = folio_create_buffers(folio, inode,
(1 << BH_Dirty) | (1 << BH_Uptodate));
/*
* Be very careful. We have no exclusion from block_dirty_folio
* here, and the (potentially unmapped) buffers may become dirty at
* any time. If a buffer becomes dirty here after we've inspected it
* then we just miss that fact, and the folio stays dirty.
*
* Buffers outside i_size may be dirtied by block_dirty_folio;
* handle that here by just cleaning them.
*/
bh = head;
blocksize = bh->b_size;
bbits = block_size_bits(blocksize);
block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
last_block = (i_size_read(inode) - 1) >> bbits;
/*
* Get all the dirty buffers mapped to disk addresses and
* handle any aliases from the underlying blockdev's mapping.
*/
do {
if (block > last_block) {
/*
* mapped buffers outside i_size will occur, because
* this folio can be outside i_size when there is a
* truncate in progress.
*/
/*
* The buffer was zeroed by block_write_full_page()
*/
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
} else if ((!buffer_mapped(bh) || buffer_delay(bh)) &&
buffer_dirty(bh)) {
WARN_ON(bh->b_size != blocksize);
err = get_block(inode, block, bh, 1);
if (err)
goto recover;
clear_buffer_delay(bh);
if (buffer_new(bh)) {
/* blockdev mappings never come here */
clear_buffer_new(bh);
clean_bdev_bh_alias(bh);
}
}
bh = bh->b_this_page;
block++;
} while (bh != head);
do {
if (!buffer_mapped(bh))
continue;
/*
* If it's a fully non-blocking write attempt and we cannot
* lock the buffer then redirty the folio. Note that this can
* potentially cause a busy-wait loop from writeback threads
* and kswapd activity, but those code paths have their own
* higher-level throttling.
*/
if (wbc->sync_mode != WB_SYNC_NONE) {
lock_buffer(bh);
} else if (!trylock_buffer(bh)) {
folio_redirty_for_writepage(wbc, folio);
continue;
}
if (test_clear_buffer_dirty(bh)) {
mark_buffer_async_write_endio(bh, handler);
} else {
unlock_buffer(bh);
}
} while ((bh = bh->b_this_page) != head);
/*
* The folio and its buffers are protected by the writeback flag,
* so we can drop the bh refcounts early.
*/
BUG_ON(folio_test_writeback(folio));
folio_start_writeback(folio);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
submit_bh_wbc(REQ_OP_WRITE | write_flags, bh, wbc);
nr_underway++;
}
bh = next;
} while (bh != head);
folio_unlock(folio);
err = 0;
done:
if (nr_underway == 0) {
/*
* The folio was marked dirty, but the buffers were
* clean. Someone wrote them back by hand with
* write_dirty_buffer/submit_bh. A rare case.
*/
folio_end_writeback(folio);
/*
* The folio and buffer_heads can be released at any time from
* here on.
*/
}
return err;
recover:
/*
* ENOSPC, or some other error. We may already have added some
* blocks to the file, so we need to write these out to avoid
* exposing stale data.
* The folio is currently locked and not marked for writeback
*/
bh = head;
/* Recovery: lock and submit the mapped buffers */
do {
if (buffer_mapped(bh) && buffer_dirty(bh) &&
!buffer_delay(bh)) {
lock_buffer(bh);
mark_buffer_async_write_endio(bh, handler);
} else {
/*
* The buffer may have been set dirty during
* attachment to a dirty folio.
*/
clear_buffer_dirty(bh);
}
} while ((bh = bh->b_this_page) != head);
folio_set_error(folio);
BUG_ON(folio_test_writeback(folio));
mapping_set_error(folio->mapping, err);
folio_start_writeback(folio);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
clear_buffer_dirty(bh);
submit_bh_wbc(REQ_OP_WRITE | write_flags, bh, wbc);
nr_underway++;
}
bh = next;
} while (bh != head);
folio_unlock(folio);
goto done;
}
EXPORT_SYMBOL(__block_write_full_folio);
/*
* If a folio has any new buffers, zero them out here, and mark them uptodate
* and dirty so they'll be written out (in order to prevent uninitialised
* block data from leaking). And clear the new bit.
*/
void folio_zero_new_buffers(struct folio *folio, size_t from, size_t to)
{
size_t block_start, block_end;
struct buffer_head *head, *bh;
BUG_ON(!folio_test_locked(folio));
head = folio_buffers(folio);
if (!head)
return;
bh = head;
block_start = 0;
do {
block_end = block_start + bh->b_size;
if (buffer_new(bh)) {
if (block_end > from && block_start < to) {
if (!folio_test_uptodate(folio)) {
size_t start, xend;
start = max(from, block_start);
xend = min(to, block_end);
folio_zero_segment(folio, start, xend);
set_buffer_uptodate(bh);
}
clear_buffer_new(bh);
mark_buffer_dirty(bh);
}
}
block_start = block_end;
bh = bh->b_this_page;
} while (bh != head);
}
EXPORT_SYMBOL(folio_zero_new_buffers);
static int
iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
const struct iomap *iomap)
{
loff_t offset = block << inode->i_blkbits;
bh->b_bdev = iomap->bdev;
/*
* Block points to offset in file we need to map, iomap contains
* the offset at which the map starts. If the map ends before the
* current block, then do not map the buffer and let the caller
* handle it.
*/
if (offset >= iomap->offset + iomap->length)
return -EIO;
switch (iomap->type) {
case IOMAP_HOLE:
/*
* If the buffer is not up to date or beyond the current EOF,
* we need to mark it as new to ensure sub-block zeroing is
* executed if necessary.
*/
if (!buffer_uptodate(bh) ||
(offset >= i_size_read(inode)))
set_buffer_new(bh);
return 0;
case IOMAP_DELALLOC:
if (!buffer_uptodate(bh) ||
(offset >= i_size_read(inode)))
set_buffer_new(bh);
set_buffer_uptodate(bh);
set_buffer_mapped(bh);
set_buffer_delay(bh);
return 0;
case IOMAP_UNWRITTEN:
/*
* For unwritten regions, we always need to ensure that regions
* in the block we are not writing to are zeroed. Mark the
* buffer as new to ensure this.
*/
set_buffer_new(bh);
set_buffer_unwritten(bh);
fallthrough;
case IOMAP_MAPPED:
if ((iomap->flags & IOMAP_F_NEW) ||
offset >= i_size_read(inode))
set_buffer_new(bh);
bh->b_blocknr = (iomap->addr + offset - iomap->offset) >>
inode->i_blkbits;
set_buffer_mapped(bh);
return 0;
default:
WARN_ON_ONCE(1);
return -EIO;
}
}
int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,
get_block_t *get_block, const struct iomap *iomap)
{
unsigned from = pos & (PAGE_SIZE - 1);
unsigned to = from + len;
struct inode *inode = folio->mapping->host;
unsigned block_start, block_end;
sector_t block;
int err = 0;
unsigned blocksize, bbits;
struct buffer_head *bh, *head, *wait[2], **wait_bh=wait;
BUG_ON(!folio_test_locked(folio));
BUG_ON(from > PAGE_SIZE);
BUG_ON(to > PAGE_SIZE);
BUG_ON(from > to);
head = folio_create_buffers(folio, inode, 0);
blocksize = head->b_size;
bbits = block_size_bits(blocksize);
block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
for(bh = head, block_start = 0; bh != head || !block_start;
block++, block_start=block_end, bh = bh->b_this_page) {
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (folio_test_uptodate(folio)) {
if (!buffer_uptodate(bh))
set_buffer_uptodate(bh);
}
continue;
}
if (buffer_new(bh))
clear_buffer_new(bh);
if (!buffer_mapped(bh)) {
WARN_ON(bh->b_size != blocksize);
if (get_block)
err = get_block(inode, block, bh, 1);
else
err = iomap_to_bh(inode, block, bh, iomap);
if (err)
break;
if (buffer_new(bh)) {
clean_bdev_bh_alias(bh);
if (folio_test_uptodate(folio)) {
clear_buffer_new(bh);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
continue;
}
if (block_end > to || block_start < from)
folio_zero_segments(folio,
to, block_end,
block_start, from);
continue;
}
}
if (folio_test_uptodate(folio)) {
if (!buffer_uptodate(bh))
set_buffer_uptodate(bh);
continue;
}
if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
!buffer_unwritten(bh) &&
(block_start < from || block_end > to)) {
bh_read_nowait(bh, 0);
*wait_bh++=bh;
}
}
/*
* If we issued read requests - let them complete.
*/
while(wait_bh > wait) {
wait_on_buffer(*--wait_bh);
if (!buffer_uptodate(*wait_bh))
err = -EIO;
}
if (unlikely(err))
folio_zero_new_buffers(folio, from, to);
return err;
}
int __block_write_begin(struct page *page, loff_t pos, unsigned len,
get_block_t *get_block)
{
return __block_write_begin_int(page_folio(page), pos, len, get_block,
NULL);
}
EXPORT_SYMBOL(__block_write_begin);
static void __block_commit_write(struct folio *folio, size_t from, size_t to)
{
size_t block_start, block_end;
bool partial = false;
unsigned blocksize;
struct buffer_head *bh, *head;
bh = head = folio_buffers(folio);
blocksize = bh->b_size;
block_start = 0;
do {
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (!buffer_uptodate(bh))
partial = true;
} else {
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
}
if (buffer_new(bh))
clear_buffer_new(bh);
block_start = block_end;
bh = bh->b_this_page;
} while (bh != head);
/*
* If this is a partial write which happened to make all buffers
* uptodate then we can optimize away a bogus read_folio() for
* the next read(). Here we 'discover' whether the folio went
* uptodate as a result of this (potentially partial) write.
*/
if (!partial)
folio_mark_uptodate(folio);
}
/*
* block_write_begin takes care of the basic task of block allocation and
* bringing partial write blocks uptodate first.
*
* The filesystem needs to handle block truncation upon failure.
*/
int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
struct page **pagep, get_block_t *get_block)
{
pgoff_t index = pos >> PAGE_SHIFT;
struct page *page;
int status;
page = grab_cache_page_write_begin(mapping, index);
if (!page)
return -ENOMEM;
status = __block_write_begin(page, pos, len, get_block);
if (unlikely(status)) {
unlock_page(page);
put_page(page);
page = NULL;
}
*pagep = page;
return status;
}
EXPORT_SYMBOL(block_write_begin);
int block_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct folio *folio = page_folio(page);
size_t start = pos - folio_pos(folio);
if (unlikely(copied < len)) {
/*
* The buffers that were written will now be uptodate, so
* we don't have to worry about a read_folio reading them
* and overwriting a partial write. However if we have
* encountered a short write and only partially written
* into a buffer, it will not be marked uptodate, so a
* read_folio might come in and destroy our partial write.
*
* Do the simplest thing, and just treat any short write to a
* non uptodate folio as a zero-length write, and force the
* caller to redo the whole thing.
*/
if (!folio_test_uptodate(folio))
copied = 0;
folio_zero_new_buffers(folio, start+copied, start+len);
}
flush_dcache_folio(folio);
/* This could be a short (even 0-length) commit */
__block_commit_write(folio, start, start + copied);
return copied;
}
EXPORT_SYMBOL(block_write_end);
int generic_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = mapping->host;
loff_t old_size = inode->i_size;
bool i_size_changed = false;
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
/*
* No need to use i_size_read() here, the i_size cannot change under us
* because we hold i_rwsem.
*
* But it's important to update i_size while still holding page lock:
* page writeout could otherwise come in and zero beyond i_size.
*/
if (pos + copied > inode->i_size) {
i_size_write(inode, pos + copied);
i_size_changed = true;
}
unlock_page(page);
put_page(page);
if (old_size < pos)
pagecache_isize_extended(inode, old_size, pos);
/*
* Don't mark the inode dirty under page lock. First, it unnecessarily
* makes the holding time of page lock longer. Second, it forces lock
* ordering of page lock and transaction start for journaling
* filesystems.
*/
if (i_size_changed)
mark_inode_dirty(inode);
return copied;
}
EXPORT_SYMBOL(generic_write_end);
/*
* block_is_partially_uptodate checks whether buffers within a folio are
* uptodate or not.
*
* Returns true if all buffers which correspond to the specified part
* of the folio are uptodate.
*/
bool block_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
{
unsigned block_start, block_end, blocksize;
unsigned to;
struct buffer_head *bh, *head;
bool ret = true;
head = folio_buffers(folio);
if (!head)
return false;
blocksize = head->b_size;
to = min_t(unsigned, folio_size(folio) - from, count);
to = from + to;
if (from < blocksize && to > folio_size(folio) - blocksize)
return false;
bh = head;
block_start = 0;
do {
block_end = block_start + blocksize;
if (block_end > from && block_start < to) {
if (!buffer_uptodate(bh)) {
ret = false;
break;
}
if (block_end >= to)
break;
}
block_start = block_end;
bh = bh->b_this_page;
} while (bh != head);
return ret;
}
EXPORT_SYMBOL(block_is_partially_uptodate);
/*
* Generic "read_folio" function for block devices that have the normal
* get_block functionality. This is most of the block device filesystems.
* Reads the folio asynchronously --- the unlock_buffer() and
* set/clear_buffer_uptodate() functions propagate buffer state into the
* folio once IO has completed.
*/
int block_read_full_folio(struct folio *folio, get_block_t *get_block)
{
struct inode *inode = folio->mapping->host;
sector_t iblock, lblock;
struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
unsigned int blocksize, bbits;
int nr, i;
int fully_mapped = 1;
bool page_error = false;
loff_t limit = i_size_read(inode);
/* This is needed for ext4. */
if (IS_ENABLED(CONFIG_FS_VERITY) && IS_VERITY(inode))
limit = inode->i_sb->s_maxbytes;
VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
head = folio_create_buffers(folio, inode, 0);
blocksize = head->b_size;
bbits = block_size_bits(blocksize);
iblock = (sector_t)folio->index << (PAGE_SHIFT - bbits);
lblock = (limit+blocksize-1) >> bbits;
bh = head;
nr = 0;
i = 0;
do {
if (buffer_uptodate(bh))
continue;
if (!buffer_mapped(bh)) {
int err = 0;
fully_mapped = 0;
if (iblock < lblock) {
WARN_ON(bh->b_size != blocksize);
err = get_block(inode, iblock, bh, 0);
if (err) {
folio_set_error(folio);
page_error = true;
}
}
if (!buffer_mapped(bh)) {
folio_zero_range(folio, i * blocksize,
blocksize);
if (!err)
set_buffer_uptodate(bh);
continue;
}
/*
* get_block() might have updated the buffer
* synchronously
*/
if (buffer_uptodate(bh))
continue;
}
arr[nr++] = bh;
} while (i++, iblock++, (bh = bh->b_this_page) != head);
if (fully_mapped)
folio_set_mappedtodisk(folio);
if (!nr) {
/*
* All buffers are uptodate - we can set the folio uptodate
* as well. But not if get_block() returned an error.
*/
if (!page_error)
folio_mark_uptodate(folio);
folio_unlock(folio);
return 0;
}
/* Stage two: lock the buffers */
for (i = 0; i < nr; i++) {
bh = arr[i];
lock_buffer(bh);
mark_buffer_async_read(bh);
}
/*
* Stage 3: start the IO. Check for uptodateness
* inside the buffer lock in case another process reading
* the underlying blockdev brought it uptodate (the sct fix).
*/
for (i = 0; i < nr; i++) {
bh = arr[i];
if (buffer_uptodate(bh))
end_buffer_async_read(bh, 1);
else
submit_bh(REQ_OP_READ, bh);
}
return 0;
}
EXPORT_SYMBOL(block_read_full_folio);
/* utility function for filesystems that need to do work on expanding
* truncates. Uses filesystem pagecache writes to allow the filesystem to
* deal with the hole.
*/
int generic_cont_expand_simple(struct inode *inode, loff_t size)
{
struct address_space *mapping = inode->i_mapping;
const struct address_space_operations *aops = mapping->a_ops;
struct page *page;
void *fsdata = NULL;
int err;
err = inode_newsize_ok(inode, size);
if (err)
goto out;
err = aops->write_begin(NULL, mapping, size, 0, &page, &fsdata);
if (err)
goto out;
err = aops->write_end(NULL, mapping, size, 0, 0, page, fsdata);
BUG_ON(err > 0);
out:
return err;
}
EXPORT_SYMBOL(generic_cont_expand_simple);
static int cont_expand_zero(struct file *file, struct address_space *mapping,
loff_t pos, loff_t *bytes)
{
struct inode *inode = mapping->host;
const struct address_space_operations *aops = mapping->a_ops;
unsigned int blocksize = i_blocksize(inode);
struct page *page;
void *fsdata = NULL;
pgoff_t index, curidx;
loff_t curpos;
unsigned zerofrom, offset, len;
int err = 0;
index = pos >> PAGE_SHIFT;
offset = pos & ~PAGE_MASK;
while (index > (curidx = (curpos = *bytes)>>PAGE_SHIFT)) {
zerofrom = curpos & ~PAGE_MASK;
if (zerofrom & (blocksize-1)) {
*bytes |= (blocksize-1);
(*bytes)++;
}
len = PAGE_SIZE - zerofrom;
err = aops->write_begin(file, mapping, curpos, len,
&page, &fsdata);
if (err)
goto out;
zero_user(page, zerofrom, len);
err = aops->write_end(file, mapping, curpos, len, len,
page, fsdata);
if (err < 0)
goto out;
BUG_ON(err != len);
err = 0;
balance_dirty_pages_ratelimited(mapping);
if (fatal_signal_pending(current)) {
err = -EINTR;
goto out;
}
}
/* page covers the boundary, find the boundary offset */
if (index == curidx) {
zerofrom = curpos & ~PAGE_MASK;
/* if we will expand the thing last block will be filled */
if (offset <= zerofrom) {
goto out;
}
if (zerofrom & (blocksize-1)) {
*bytes |= (blocksize-1);
(*bytes)++;
}
len = offset - zerofrom;
err = aops->write_begin(file, mapping, curpos, len,
&page, &fsdata);
if (err)
goto out;
zero_user(page, zerofrom, len);
err = aops->write_end(file, mapping, curpos, len, len,
page, fsdata);
if (err < 0)
goto out;
BUG_ON(err != len);
err = 0;
}
out:
return err;
}
/*
* For moronic filesystems that do not allow holes in file.
* We may have to extend the file.
*/
int cont_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len,
struct page **pagep, void **fsdata,
get_block_t *get_block, loff_t *bytes)
{
struct inode *inode = mapping->host;
unsigned int blocksize = i_blocksize(inode);
unsigned int zerofrom;
int err;
err = cont_expand_zero(file, mapping, pos, bytes);
if (err)
return err;
zerofrom = *bytes & ~PAGE_MASK;
if (pos+len > *bytes && zerofrom & (blocksize-1)) {
*bytes |= (blocksize-1);
(*bytes)++;
}
return block_write_begin(mapping, pos, len, pagep, get_block);
}
EXPORT_SYMBOL(cont_write_begin);
void block_commit_write(struct page *page, unsigned from, unsigned to)
{
struct folio *folio = page_folio(page);
__block_commit_write(folio, from, to);
}
EXPORT_SYMBOL(block_commit_write);
/*
* block_page_mkwrite() is not allowed to change the file size as it gets
* called from a page fault handler when a page is first dirtied. Hence we must
* be careful to check for EOF conditions here. We set the page up correctly
* for a written page which means we get ENOSPC checking when writing into
* holes and correct delalloc and unwritten extent mapping on filesystems that
* support these features.
*
* We are not allowed to take the i_mutex here so we have to play games to
* protect against truncate races as the page could now be beyond EOF. Because
* truncate writes the inode size before removing pages, once we have the
* page lock we can determine safely if the page is beyond EOF. If it is not
* beyond EOF, then the page is guaranteed safe against truncation until we
* unlock the page.
*
* Direct callers of this function should protect against filesystem freezing
* using sb_start_pagefault() - sb_end_pagefault() functions.
*/
int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
get_block_t get_block)
{
struct folio *folio = page_folio(vmf->page);
struct inode *inode = file_inode(vma->vm_file);
unsigned long end;
loff_t size;
int ret;
folio_lock(folio);
size = i_size_read(inode);
if ((folio->mapping != inode->i_mapping) ||
(folio_pos(folio) >= size)) {
/* We overload EFAULT to mean page got truncated */
ret = -EFAULT;
goto out_unlock;
}
end = folio_size(folio);
/* folio is wholly or partially inside EOF */
if (folio_pos(folio) + end > size)
end = size - folio_pos(folio);
ret = __block_write_begin_int(folio, 0, end, get_block, NULL);
if (unlikely(ret))
goto out_unlock;
__block_commit_write(folio, 0, end);
folio_mark_dirty(folio);
folio_wait_stable(folio);
return 0;
out_unlock:
folio_unlock(folio);
return ret;
}
EXPORT_SYMBOL(block_page_mkwrite);
int block_truncate_page(struct address_space *mapping,
loff_t from, get_block_t *get_block)
{
pgoff_t index = from >> PAGE_SHIFT;
unsigned blocksize;
sector_t iblock;
size_t offset, length, pos;
struct inode *inode = mapping->host;
struct folio *folio;
struct buffer_head *bh;
int err = 0;
blocksize = i_blocksize(inode);
length = from & (blocksize - 1);
/* Block boundary? Nothing to do */
if (!length)
return 0;
length = blocksize - length;
iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits);
folio = filemap_grab_folio(mapping, index);
if (IS_ERR(folio))
return PTR_ERR(folio);
bh = folio_buffers(folio);
if (!bh) {
folio_create_empty_buffers(folio, blocksize, 0);
bh = folio_buffers(folio);
}
/* Find the buffer that contains "offset" */
offset = offset_in_folio(folio, from);
pos = blocksize;
while (offset >= pos) {
bh = bh->b_this_page;
iblock++;
pos += blocksize;
}
if (!buffer_mapped(bh)) {
WARN_ON(bh->b_size != blocksize);
err = get_block(inode, iblock, bh, 0);
if (err)
goto unlock;
/* unmapped? It's a hole - nothing to do */
if (!buffer_mapped(bh))
goto unlock;
}
/* Ok, it's mapped. Make sure it's up-to-date */
if (folio_test_uptodate(folio))
set_buffer_uptodate(bh);
if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) {
err = bh_read(bh, 0);
/* Uhhuh. Read error. Complain and punt. */
if (err < 0)
goto unlock;
}
folio_zero_range(folio, offset, length);
mark_buffer_dirty(bh);
unlock:
folio_unlock(folio);
folio_put(folio);
return err;
}
EXPORT_SYMBOL(block_truncate_page);
/*
* The generic ->writepage function for buffer-backed address_spaces
*/
int block_write_full_page(struct page *page, get_block_t *get_block,
struct writeback_control *wbc)
{
struct folio *folio = page_folio(page);
struct inode * const inode = folio->mapping->host;
loff_t i_size = i_size_read(inode);
/* Is the folio fully inside i_size? */
if (folio_pos(folio) + folio_size(folio) <= i_size)
return __block_write_full_folio(inode, folio, get_block, wbc,
end_buffer_async_write);
/* Is the folio fully outside i_size? (truncate in progress) */
if (folio_pos(folio) >= i_size) {
folio_unlock(folio);
return 0; /* don't care */
}
/*
* The folio straddles i_size. It must be zeroed out on each and every
* writepage invocation because it may be mmapped. "A file is mapped
* in multiples of the page size. For a file that is not a multiple of
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
folio_zero_segment(folio, offset_in_folio(folio, i_size),
folio_size(folio));
return __block_write_full_folio(inode, folio, get_block, wbc,
end_buffer_async_write);
}
EXPORT_SYMBOL(block_write_full_page);
sector_t generic_block_bmap(struct address_space *mapping, sector_t block,
get_block_t *get_block)
{
struct inode *inode = mapping->host;
struct buffer_head tmp = {
.b_size = i_blocksize(inode),
};
get_block(inode, block, &tmp, 0);
return tmp.b_blocknr;
}
EXPORT_SYMBOL(generic_block_bmap);
static void end_bio_bh_io_sync(struct bio *bio)
{
struct buffer_head *bh = bio->bi_private;
if (unlikely(bio_flagged(bio, BIO_QUIET)))
set_bit(BH_Quiet, &bh->b_state);
bh->b_end_io(bh, !bio->bi_status);
bio_put(bio);
}
static void submit_bh_wbc(blk_opf_t opf, struct buffer_head *bh,
struct writeback_control *wbc)
{
const enum req_op op = opf & REQ_OP_MASK;
struct bio *bio;
BUG_ON(!buffer_locked(bh));
BUG_ON(!buffer_mapped(bh));
BUG_ON(!bh->b_end_io);
BUG_ON(buffer_delay(bh));
BUG_ON(buffer_unwritten(bh));
/*
* Only clear out a write error when rewriting
*/
if (test_set_buffer_req(bh) && (op == REQ_OP_WRITE))
clear_buffer_write_io_error(bh);
if (buffer_meta(bh))
opf |= REQ_META;
if (buffer_prio(bh))
opf |= REQ_PRIO;
bio = bio_alloc(bh->b_bdev, 1, opf, GFP_NOIO);
fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
__bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
bio->bi_end_io = end_bio_bh_io_sync;
bio->bi_private = bh;
/* Take care of bh's that straddle the end of the device */
guard_bio_eod(bio);
if (wbc) {
wbc_init_bio(wbc, bio);
wbc_account_cgroup_owner(wbc, bh->b_page, bh->b_size);
}
submit_bio(bio);
}
void submit_bh(blk_opf_t opf, struct buffer_head *bh)
{
submit_bh_wbc(opf, bh, NULL);
}
EXPORT_SYMBOL(submit_bh);
void write_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags)
{
lock_buffer(bh);
if (!test_clear_buffer_dirty(bh)) {
unlock_buffer(bh);
return;
}
bh->b_end_io = end_buffer_write_sync;
get_bh(bh);
submit_bh(REQ_OP_WRITE | op_flags, bh);
}
EXPORT_SYMBOL(write_dirty_buffer);
/*
* For a data-integrity writeout, we need to wait upon any in-progress I/O
* and then start new I/O and then wait upon it. The caller must have a ref on
* the buffer_head.
*/
int __sync_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags)
{
WARN_ON(atomic_read(&bh->b_count) < 1);
lock_buffer(bh);
if (test_clear_buffer_dirty(bh)) {
/*
* The bh should be mapped, but it might not be if the
* device was hot-removed. Not much we can do but fail the I/O.
*/
if (!buffer_mapped(bh)) {
unlock_buffer(bh);
return -EIO;
}
get_bh(bh);
bh->b_end_io = end_buffer_write_sync;
submit_bh(REQ_OP_WRITE | op_flags, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
return -EIO;
} else {
unlock_buffer(bh);
}
return 0;
}
EXPORT_SYMBOL(__sync_dirty_buffer);
int sync_dirty_buffer(struct buffer_head *bh)
{
return __sync_dirty_buffer(bh, REQ_SYNC);
}
EXPORT_SYMBOL(sync_dirty_buffer);
/*
* try_to_free_buffers() checks if all the buffers on this particular folio
* are unused, and releases them if so.
*
* Exclusion against try_to_free_buffers may be obtained by either
* locking the folio or by holding its mapping's private_lock.
*
* If the folio is dirty but all the buffers are clean then we need to
* be sure to mark the folio clean as well. This is because the folio
* may be against a block device, and a later reattachment of buffers
* to a dirty folio will set *all* buffers dirty. Which would corrupt
* filesystem data on the same device.
*
* The same applies to regular filesystem folios: if all the buffers are
* clean then we set the folio clean and proceed. To do that, we require
* total exclusion from block_dirty_folio(). That is obtained with
* private_lock.
*
* try_to_free_buffers() is non-blocking.
*/
static inline int buffer_busy(struct buffer_head *bh)
{
return atomic_read(&bh->b_count) |
(bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock)));
}
static bool
drop_buffers(struct folio *folio, struct buffer_head **buffers_to_free)
{
struct buffer_head *head = folio_buffers(folio);
struct buffer_head *bh;
bh = head;
do {
if (buffer_busy(bh))
goto failed;
bh = bh->b_this_page;
} while (bh != head);
do {
struct buffer_head *next = bh->b_this_page;
if (bh->b_assoc_map)
__remove_assoc_queue(bh);
bh = next;
} while (bh != head);
*buffers_to_free = head;
folio_detach_private(folio);
return true;
failed:
return false;
}
bool try_to_free_buffers(struct folio *folio)
{
struct address_space * const mapping = folio->mapping;
struct buffer_head *buffers_to_free = NULL;
bool ret = 0;
BUG_ON(!folio_test_locked(folio));
if (folio_test_writeback(folio))
return false;
if (mapping == NULL) { /* can this still happen? */
ret = drop_buffers(folio, &buffers_to_free);
goto out;
}
spin_lock(&mapping->private_lock);
ret = drop_buffers(folio, &buffers_to_free);
/*
* If the filesystem writes its buffers by hand (eg ext3)
* then we can have clean buffers against a dirty folio. We
* clean the folio here; otherwise the VM will never notice
* that the filesystem did any IO at all.
*
* Also, during truncate, discard_buffer will have marked all
* the folio's buffers clean. We discover that here and clean
* the folio also.
*
* private_lock must be held over this entire operation in order
* to synchronise against block_dirty_folio and prevent the
* dirty bit from being lost.
*/
if (ret)
folio_cancel_dirty(folio);
spin_unlock(&mapping->private_lock);
out:
if (buffers_to_free) {
struct buffer_head *bh = buffers_to_free;
do {
struct buffer_head *next = bh->b_this_page;
free_buffer_head(bh);
bh = next;
} while (bh != buffers_to_free);
}
return ret;
}
EXPORT_SYMBOL(try_to_free_buffers);
/*
* Buffer-head allocation
*/
static struct kmem_cache *bh_cachep __read_mostly;
/*
* Once the number of bh's in the machine exceeds this level, we start
* stripping them in writeback.
*/
static unsigned long max_buffer_heads;
int buffer_heads_over_limit;
struct bh_accounting {
int nr; /* Number of live bh's */
int ratelimit; /* Limit cacheline bouncing */
};
static DEFINE_PER_CPU(struct bh_accounting, bh_accounting) = {0, 0};
static void recalc_bh_state(void)
{
int i;
int tot = 0;
if (__this_cpu_inc_return(bh_accounting.ratelimit) - 1 < 4096)
return;
__this_cpu_write(bh_accounting.ratelimit, 0);
for_each_online_cpu(i)
tot += per_cpu(bh_accounting, i).nr;
buffer_heads_over_limit = (tot > max_buffer_heads);
}
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags)
{
struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags);
if (ret) {
INIT_LIST_HEAD(&ret->b_assoc_buffers);
spin_lock_init(&ret->b_uptodate_lock);
preempt_disable();
__this_cpu_inc(bh_accounting.nr);
recalc_bh_state();
preempt_enable();
}
return ret;
}
EXPORT_SYMBOL(alloc_buffer_head);
void free_buffer_head(struct buffer_head *bh)
{
BUG_ON(!list_empty(&bh->b_assoc_buffers));
kmem_cache_free(bh_cachep, bh);
preempt_disable();
__this_cpu_dec(bh_accounting.nr);
recalc_bh_state();
preempt_enable();
}
EXPORT_SYMBOL(free_buffer_head);
static int buffer_exit_cpu_dead(unsigned int cpu)
{
int i;
struct bh_lru *b = &per_cpu(bh_lrus, cpu);
for (i = 0; i < BH_LRU_SIZE; i++) {
brelse(b->bhs[i]);
b->bhs[i] = NULL;
}
this_cpu_add(bh_accounting.nr, per_cpu(bh_accounting, cpu).nr);
per_cpu(bh_accounting, cpu).nr = 0;
return 0;
}
/**
* bh_uptodate_or_lock - Test whether the buffer is uptodate
* @bh: struct buffer_head
*
* Return true if the buffer is up-to-date and false,
* with the buffer locked, if not.
*/
int bh_uptodate_or_lock(struct buffer_head *bh)
{
if (!buffer_uptodate(bh)) {
lock_buffer(bh);
if (!buffer_uptodate(bh))
return 0;
unlock_buffer(bh);
}
return 1;
}
EXPORT_SYMBOL(bh_uptodate_or_lock);
/**
* __bh_read - Submit read for a locked buffer
* @bh: struct buffer_head
* @op_flags: appending REQ_OP_* flags besides REQ_OP_READ
* @wait: wait until reading finish
*
* Returns zero on success or don't wait, and -EIO on error.
*/
int __bh_read(struct buffer_head *bh, blk_opf_t op_flags, bool wait)
{
int ret = 0;
BUG_ON(!buffer_locked(bh));
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(REQ_OP_READ | op_flags, bh);
if (wait) {
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
ret = -EIO;
}
return ret;
}
EXPORT_SYMBOL(__bh_read);
/**
* __bh_read_batch - Submit read for a batch of unlocked buffers
* @nr: entry number of the buffer batch
* @bhs: a batch of struct buffer_head
* @op_flags: appending REQ_OP_* flags besides REQ_OP_READ
* @force_lock: force to get a lock on the buffer if set, otherwise drops any
* buffer that cannot lock.
*
* Returns zero on success or don't wait, and -EIO on error.
*/
void __bh_read_batch(int nr, struct buffer_head *bhs[],
blk_opf_t op_flags, bool force_lock)
{
int i;
for (i = 0; i < nr; i++) {
struct buffer_head *bh = bhs[i];
if (buffer_uptodate(bh))
continue;
if (force_lock)
lock_buffer(bh);
else
if (!trylock_buffer(bh))
continue;
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
continue;
}
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
submit_bh(REQ_OP_READ | op_flags, bh);
}
}
EXPORT_SYMBOL(__bh_read_batch);
void __init buffer_init(void)
{
unsigned long nrpages;
int ret;
bh_cachep = kmem_cache_create("buffer_head",
sizeof(struct buffer_head), 0,
(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
SLAB_MEM_SPREAD),
NULL);
/*
* Limit the bh occupancy to 10% of ZONE_NORMAL
*/
nrpages = (nr_free_buffer_pages() * 10) / 100;
max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head));
ret = cpuhp_setup_state_nocalls(CPUHP_FS_BUFF_DEAD, "fs/buffer:dead",
NULL, buffer_exit_cpu_dead);
WARN_ON(ret < 0);
}
| linux-master | fs/buffer.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* "splice": joining two ropes together by interweaving their strands.
*
* This is the "extended pipe" functionality, where a pipe is used as
* an arbitrary in-memory buffer. Think of a pipe as a small kernel
* buffer that you can use to transfer data from one end to the other.
*
* The traditional unix read/write is extended with a "splice()" operation
* that transfers data buffers to or from a pipe buffer.
*
* Named by Larry McVoy, original implementation from Linus, extended by
* Jens to support splicing to files, network, direct splicing, etc and
* fixing lots of bugs.
*
* Copyright (C) 2005-2006 Jens Axboe <[email protected]>
* Copyright (C) 2005-2006 Linus Torvalds <[email protected]>
* Copyright (C) 2006 Ingo Molnar <[email protected]>
*
*/
#include <linux/bvec.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/splice.h>
#include <linux/memcontrol.h>
#include <linux/mm_inline.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/uio.h>
#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/gfp.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/sched/signal.h>
#include "internal.h"
/*
* Splice doesn't support FMODE_NOWAIT. Since pipes may set this flag to
* indicate they support non-blocking reads or writes, we must clear it
* here if set to avoid blocking other users of this pipe if splice is
* being done on it.
*/
static noinline void noinline pipe_clear_nowait(struct file *file)
{
fmode_t fmode = READ_ONCE(file->f_mode);
do {
if (!(fmode & FMODE_NOWAIT))
break;
} while (!try_cmpxchg(&file->f_mode, &fmode, fmode & ~FMODE_NOWAIT));
}
/*
* Attempt to steal a page from a pipe buffer. This should perhaps go into
* a vm helper function, it's already simplified quite a bit by the
* addition of remove_mapping(). If success is returned, the caller may
* attempt to reuse this page for another destination.
*/
static bool page_cache_pipe_buf_try_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct folio *folio = page_folio(buf->page);
struct address_space *mapping;
folio_lock(folio);
mapping = folio_mapping(folio);
if (mapping) {
WARN_ON(!folio_test_uptodate(folio));
/*
* At least for ext2 with nobh option, we need to wait on
* writeback completing on this folio, since we'll remove it
* from the pagecache. Otherwise truncate wont wait on the
* folio, allowing the disk blocks to be reused by someone else
* before we actually wrote our data to them. fs corruption
* ensues.
*/
folio_wait_writeback(folio);
if (!filemap_release_folio(folio, GFP_KERNEL))
goto out_unlock;
/*
* If we succeeded in removing the mapping, set LRU flag
* and return good.
*/
if (remove_mapping(mapping, folio)) {
buf->flags |= PIPE_BUF_FLAG_LRU;
return true;
}
}
/*
* Raced with truncate or failed to remove folio from current
* address space, unlock and return failure.
*/
out_unlock:
folio_unlock(folio);
return false;
}
static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
put_page(buf->page);
buf->flags &= ~PIPE_BUF_FLAG_LRU;
}
/*
* Check whether the contents of buf is OK to access. Since the content
* is a page cache page, IO may be in flight.
*/
static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct folio *folio = page_folio(buf->page);
int err;
if (!folio_test_uptodate(folio)) {
folio_lock(folio);
/*
* Folio got truncated/unhashed. This will cause a 0-byte
* splice, if this is the first page.
*/
if (!folio->mapping) {
err = -ENODATA;
goto error;
}
/*
* Uh oh, read-error from disk.
*/
if (!folio_test_uptodate(folio)) {
err = -EIO;
goto error;
}
/* Folio is ok after all, we are done */
folio_unlock(folio);
}
return 0;
error:
folio_unlock(folio);
return err;
}
const struct pipe_buf_operations page_cache_pipe_buf_ops = {
.confirm = page_cache_pipe_buf_confirm,
.release = page_cache_pipe_buf_release,
.try_steal = page_cache_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
static bool user_page_pipe_buf_try_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
return false;
buf->flags |= PIPE_BUF_FLAG_LRU;
return generic_pipe_buf_try_steal(pipe, buf);
}
static const struct pipe_buf_operations user_page_pipe_buf_ops = {
.release = page_cache_pipe_buf_release,
.try_steal = user_page_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
static void wakeup_pipe_readers(struct pipe_inode_info *pipe)
{
smp_mb();
if (waitqueue_active(&pipe->rd_wait))
wake_up_interruptible(&pipe->rd_wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
}
/**
* splice_to_pipe - fill passed data into a pipe
* @pipe: pipe to fill
* @spd: data to fill
*
* Description:
* @spd contains a map of pages and len/offset tuples, along with
* the struct pipe_buf_operations associated with these pages. This
* function will link that data to the pipe.
*
*/
ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd)
{
unsigned int spd_pages = spd->nr_pages;
unsigned int tail = pipe->tail;
unsigned int head = pipe->head;
unsigned int mask = pipe->ring_size - 1;
int ret = 0, page_nr = 0;
if (!spd_pages)
return 0;
if (unlikely(!pipe->readers)) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
goto out;
}
while (!pipe_full(head, tail, pipe->max_usage)) {
struct pipe_buffer *buf = &pipe->bufs[head & mask];
buf->page = spd->pages[page_nr];
buf->offset = spd->partial[page_nr].offset;
buf->len = spd->partial[page_nr].len;
buf->private = spd->partial[page_nr].private;
buf->ops = spd->ops;
buf->flags = 0;
head++;
pipe->head = head;
page_nr++;
ret += buf->len;
if (!--spd->nr_pages)
break;
}
if (!ret)
ret = -EAGAIN;
out:
while (page_nr < spd_pages)
spd->spd_release(spd, page_nr++);
return ret;
}
EXPORT_SYMBOL_GPL(splice_to_pipe);
ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
{
unsigned int head = pipe->head;
unsigned int tail = pipe->tail;
unsigned int mask = pipe->ring_size - 1;
int ret;
if (unlikely(!pipe->readers)) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
} else if (pipe_full(head, tail, pipe->max_usage)) {
ret = -EAGAIN;
} else {
pipe->bufs[head & mask] = *buf;
pipe->head = head + 1;
return buf->len;
}
pipe_buf_release(pipe, buf);
return ret;
}
EXPORT_SYMBOL(add_to_pipe);
/*
* Check if we need to grow the arrays holding pages and partial page
* descriptions.
*/
int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd)
{
unsigned int max_usage = READ_ONCE(pipe->max_usage);
spd->nr_pages_max = max_usage;
if (max_usage <= PIPE_DEF_BUFFERS)
return 0;
spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL);
spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page),
GFP_KERNEL);
if (spd->pages && spd->partial)
return 0;
kfree(spd->pages);
kfree(spd->partial);
return -ENOMEM;
}
void splice_shrink_spd(struct splice_pipe_desc *spd)
{
if (spd->nr_pages_max <= PIPE_DEF_BUFFERS)
return;
kfree(spd->pages);
kfree(spd->partial);
}
/**
* copy_splice_read - Copy data from a file and splice the copy into a pipe
* @in: The file to read from
* @ppos: Pointer to the file position to read from
* @pipe: The pipe to splice into
* @len: The amount to splice
* @flags: The SPLICE_F_* flags
*
* This function allocates a bunch of pages sufficient to hold the requested
* amount of data (but limited by the remaining pipe capacity), passes it to
* the file's ->read_iter() to read into and then splices the used pages into
* the pipe.
*
* Return: On success, the number of bytes read will be returned and *@ppos
* will be updated if appropriate; 0 will be returned if there is no more data
* to be read; -EAGAIN will be returned if the pipe had no space, and some
* other negative error code will be returned on error. A short read may occur
* if the pipe has insufficient space, we reach the end of the data or we hit a
* hole.
*/
ssize_t copy_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len, unsigned int flags)
{
struct iov_iter to;
struct bio_vec *bv;
struct kiocb kiocb;
struct page **pages;
ssize_t ret;
size_t used, npages, chunk, remain, keep = 0;
int i;
/* Work out how much data we can actually add into the pipe */
used = pipe_occupancy(pipe->head, pipe->tail);
npages = max_t(ssize_t, pipe->max_usage - used, 0);
len = min_t(size_t, len, npages * PAGE_SIZE);
npages = DIV_ROUND_UP(len, PAGE_SIZE);
bv = kzalloc(array_size(npages, sizeof(bv[0])) +
array_size(npages, sizeof(struct page *)), GFP_KERNEL);
if (!bv)
return -ENOMEM;
pages = (struct page **)(bv + npages);
npages = alloc_pages_bulk_array(GFP_USER, npages, pages);
if (!npages) {
kfree(bv);
return -ENOMEM;
}
remain = len = min_t(size_t, len, npages * PAGE_SIZE);
for (i = 0; i < npages; i++) {
chunk = min_t(size_t, PAGE_SIZE, remain);
bv[i].bv_page = pages[i];
bv[i].bv_offset = 0;
bv[i].bv_len = chunk;
remain -= chunk;
}
/* Do the I/O */
iov_iter_bvec(&to, ITER_DEST, bv, npages, len);
init_sync_kiocb(&kiocb, in);
kiocb.ki_pos = *ppos;
ret = call_read_iter(in, &kiocb, &to);
if (ret > 0) {
keep = DIV_ROUND_UP(ret, PAGE_SIZE);
*ppos = kiocb.ki_pos;
}
/*
* Callers of ->splice_read() expect -EAGAIN on "can't put anything in
* there", rather than -EFAULT.
*/
if (ret == -EFAULT)
ret = -EAGAIN;
/* Free any pages that didn't get touched at all. */
if (keep < npages)
release_pages(pages + keep, npages - keep);
/* Push the remaining pages into the pipe. */
remain = ret;
for (i = 0; i < keep; i++) {
struct pipe_buffer *buf = pipe_head_buf(pipe);
chunk = min_t(size_t, remain, PAGE_SIZE);
*buf = (struct pipe_buffer) {
.ops = &default_pipe_buf_ops,
.page = bv[i].bv_page,
.offset = 0,
.len = chunk,
};
pipe->head++;
remain -= chunk;
}
kfree(bv);
return ret;
}
EXPORT_SYMBOL(copy_splice_read);
const struct pipe_buf_operations default_pipe_buf_ops = {
.release = generic_pipe_buf_release,
.try_steal = generic_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
/* Pipe buffer operations for a socket and similar. */
const struct pipe_buf_operations nosteal_pipe_buf_ops = {
.release = generic_pipe_buf_release,
.get = generic_pipe_buf_get,
};
EXPORT_SYMBOL(nosteal_pipe_buf_ops);
static void wakeup_pipe_writers(struct pipe_inode_info *pipe)
{
smp_mb();
if (waitqueue_active(&pipe->wr_wait))
wake_up_interruptible(&pipe->wr_wait);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
/**
* splice_from_pipe_feed - feed available data from a pipe to a file
* @pipe: pipe to splice from
* @sd: information to @actor
* @actor: handler that splices the data
*
* Description:
* This function loops over the pipe and calls @actor to do the
* actual moving of a single struct pipe_buffer to the desired
* destination. It returns when there's no more buffers left in
* the pipe or if the requested number of bytes (@sd->total_len)
* have been copied. It returns a positive number (one) if the
* pipe needs to be filled with more data, zero if the required
* number of bytes have been copied and -errno on error.
*
* This, together with splice_from_pipe_{begin,end,next}, may be
* used to implement the functionality of __splice_from_pipe() when
* locking is required around copying the pipe buffers to the
* destination.
*/
static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd,
splice_actor *actor)
{
unsigned int head = pipe->head;
unsigned int tail = pipe->tail;
unsigned int mask = pipe->ring_size - 1;
int ret;
while (!pipe_empty(head, tail)) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
sd->len = buf->len;
if (sd->len > sd->total_len)
sd->len = sd->total_len;
ret = pipe_buf_confirm(pipe, buf);
if (unlikely(ret)) {
if (ret == -ENODATA)
ret = 0;
return ret;
}
ret = actor(pipe, buf, sd);
if (ret <= 0)
return ret;
buf->offset += ret;
buf->len -= ret;
sd->num_spliced += ret;
sd->len -= ret;
sd->pos += ret;
sd->total_len -= ret;
if (!buf->len) {
pipe_buf_release(pipe, buf);
tail++;
pipe->tail = tail;
if (pipe->files)
sd->need_wakeup = true;
}
if (!sd->total_len)
return 0;
}
return 1;
}
/* We know we have a pipe buffer, but maybe it's empty? */
static inline bool eat_empty_buffer(struct pipe_inode_info *pipe)
{
unsigned int tail = pipe->tail;
unsigned int mask = pipe->ring_size - 1;
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
if (unlikely(!buf->len)) {
pipe_buf_release(pipe, buf);
pipe->tail = tail+1;
return true;
}
return false;
}
/**
* splice_from_pipe_next - wait for some data to splice from
* @pipe: pipe to splice from
* @sd: information about the splice operation
*
* Description:
* This function will wait for some data and return a positive
* value (one) if pipe buffers are available. It will return zero
* or -errno if no more data needs to be spliced.
*/
static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd)
{
/*
* Check for signal early to make process killable when there are
* always buffers available
*/
if (signal_pending(current))
return -ERESTARTSYS;
repeat:
while (pipe_empty(pipe->head, pipe->tail)) {
if (!pipe->writers)
return 0;
if (sd->num_spliced)
return 0;
if (sd->flags & SPLICE_F_NONBLOCK)
return -EAGAIN;
if (signal_pending(current))
return -ERESTARTSYS;
if (sd->need_wakeup) {
wakeup_pipe_writers(pipe);
sd->need_wakeup = false;
}
pipe_wait_readable(pipe);
}
if (eat_empty_buffer(pipe))
goto repeat;
return 1;
}
/**
* splice_from_pipe_begin - start splicing from pipe
* @sd: information about the splice operation
*
* Description:
* This function should be called before a loop containing
* splice_from_pipe_next() and splice_from_pipe_feed() to
* initialize the necessary fields of @sd.
*/
static void splice_from_pipe_begin(struct splice_desc *sd)
{
sd->num_spliced = 0;
sd->need_wakeup = false;
}
/**
* splice_from_pipe_end - finish splicing from pipe
* @pipe: pipe to splice from
* @sd: information about the splice operation
*
* Description:
* This function will wake up pipe writers if necessary. It should
* be called after a loop containing splice_from_pipe_next() and
* splice_from_pipe_feed().
*/
static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd)
{
if (sd->need_wakeup)
wakeup_pipe_writers(pipe);
}
/**
* __splice_from_pipe - splice data from a pipe to given actor
* @pipe: pipe to splice from
* @sd: information to @actor
* @actor: handler that splices the data
*
* Description:
* This function does little more than loop over the pipe and call
* @actor to do the actual moving of a single struct pipe_buffer to
* the desired destination. See pipe_to_file, pipe_to_sendmsg, or
* pipe_to_user.
*
*/
ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd,
splice_actor *actor)
{
int ret;
splice_from_pipe_begin(sd);
do {
cond_resched();
ret = splice_from_pipe_next(pipe, sd);
if (ret > 0)
ret = splice_from_pipe_feed(pipe, sd, actor);
} while (ret > 0);
splice_from_pipe_end(pipe, sd);
return sd->num_spliced ? sd->num_spliced : ret;
}
EXPORT_SYMBOL(__splice_from_pipe);
/**
* splice_from_pipe - splice data from a pipe to a file
* @pipe: pipe to splice from
* @out: file to splice to
* @ppos: position in @out
* @len: how many bytes to splice
* @flags: splice modifier flags
* @actor: handler that splices the data
*
* Description:
* See __splice_from_pipe. This function locks the pipe inode,
* otherwise it's identical to __splice_from_pipe().
*
*/
ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags,
splice_actor *actor)
{
ssize_t ret;
struct splice_desc sd = {
.total_len = len,
.flags = flags,
.pos = *ppos,
.u.file = out,
};
pipe_lock(pipe);
ret = __splice_from_pipe(pipe, &sd, actor);
pipe_unlock(pipe);
return ret;
}
/**
* iter_file_splice_write - splice data from a pipe to a file
* @pipe: pipe info
* @out: file to write to
* @ppos: position in @out
* @len: number of bytes to splice
* @flags: splice modifier flags
*
* Description:
* Will either move or copy pages (determined by @flags options) from
* the given pipe inode to the given file.
* This one is ->write_iter-based.
*
*/
ssize_t
iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
struct splice_desc sd = {
.total_len = len,
.flags = flags,
.pos = *ppos,
.u.file = out,
};
int nbufs = pipe->max_usage;
struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec),
GFP_KERNEL);
ssize_t ret;
if (unlikely(!array))
return -ENOMEM;
pipe_lock(pipe);
splice_from_pipe_begin(&sd);
while (sd.total_len) {
struct iov_iter from;
unsigned int head, tail, mask;
size_t left;
int n;
ret = splice_from_pipe_next(pipe, &sd);
if (ret <= 0)
break;
if (unlikely(nbufs < pipe->max_usage)) {
kfree(array);
nbufs = pipe->max_usage;
array = kcalloc(nbufs, sizeof(struct bio_vec),
GFP_KERNEL);
if (!array) {
ret = -ENOMEM;
break;
}
}
head = pipe->head;
tail = pipe->tail;
mask = pipe->ring_size - 1;
/* build the vector */
left = sd.total_len;
for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
size_t this_len = buf->len;
/* zero-length bvecs are not supported, skip them */
if (!this_len)
continue;
this_len = min(this_len, left);
ret = pipe_buf_confirm(pipe, buf);
if (unlikely(ret)) {
if (ret == -ENODATA)
ret = 0;
goto done;
}
bvec_set_page(&array[n], buf->page, this_len,
buf->offset);
left -= this_len;
n++;
}
iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left);
ret = vfs_iter_write(out, &from, &sd.pos, 0);
if (ret <= 0)
break;
sd.num_spliced += ret;
sd.total_len -= ret;
*ppos = sd.pos;
/* dismiss the fully eaten buffers, adjust the partial one */
tail = pipe->tail;
while (ret) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
if (ret >= buf->len) {
ret -= buf->len;
buf->len = 0;
pipe_buf_release(pipe, buf);
tail++;
pipe->tail = tail;
if (pipe->files)
sd.need_wakeup = true;
} else {
buf->offset += ret;
buf->len -= ret;
ret = 0;
}
}
}
done:
kfree(array);
splice_from_pipe_end(pipe, &sd);
pipe_unlock(pipe);
if (sd.num_spliced)
ret = sd.num_spliced;
return ret;
}
EXPORT_SYMBOL(iter_file_splice_write);
#ifdef CONFIG_NET
/**
* splice_to_socket - splice data from a pipe to a socket
* @pipe: pipe to splice from
* @out: socket to write to
* @ppos: position in @out
* @len: number of bytes to splice
* @flags: splice modifier flags
*
* Description:
* Will send @len bytes from the pipe to a network socket. No data copying
* is involved.
*
*/
ssize_t splice_to_socket(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
struct socket *sock = sock_from_file(out);
struct bio_vec bvec[16];
struct msghdr msg = {};
ssize_t ret = 0;
size_t spliced = 0;
bool need_wakeup = false;
pipe_lock(pipe);
while (len > 0) {
unsigned int head, tail, mask, bc = 0;
size_t remain = len;
/*
* Check for signal early to make process killable when there
* are always buffers available
*/
ret = -ERESTARTSYS;
if (signal_pending(current))
break;
while (pipe_empty(pipe->head, pipe->tail)) {
ret = 0;
if (!pipe->writers)
goto out;
if (spliced)
goto out;
ret = -EAGAIN;
if (flags & SPLICE_F_NONBLOCK)
goto out;
ret = -ERESTARTSYS;
if (signal_pending(current))
goto out;
if (need_wakeup) {
wakeup_pipe_writers(pipe);
need_wakeup = false;
}
pipe_wait_readable(pipe);
}
head = pipe->head;
tail = pipe->tail;
mask = pipe->ring_size - 1;
while (!pipe_empty(head, tail)) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
size_t seg;
if (!buf->len) {
tail++;
continue;
}
seg = min_t(size_t, remain, buf->len);
ret = pipe_buf_confirm(pipe, buf);
if (unlikely(ret)) {
if (ret == -ENODATA)
ret = 0;
break;
}
bvec_set_page(&bvec[bc++], buf->page, seg, buf->offset);
remain -= seg;
if (remain == 0 || bc >= ARRAY_SIZE(bvec))
break;
tail++;
}
if (!bc)
break;
msg.msg_flags = MSG_SPLICE_PAGES;
if (flags & SPLICE_F_MORE)
msg.msg_flags |= MSG_MORE;
if (remain && pipe_occupancy(pipe->head, tail) > 0)
msg.msg_flags |= MSG_MORE;
if (out->f_flags & O_NONBLOCK)
msg.msg_flags |= MSG_DONTWAIT;
iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, bvec, bc,
len - remain);
ret = sock_sendmsg(sock, &msg);
if (ret <= 0)
break;
spliced += ret;
len -= ret;
tail = pipe->tail;
while (ret > 0) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
size_t seg = min_t(size_t, ret, buf->len);
buf->offset += seg;
buf->len -= seg;
ret -= seg;
if (!buf->len) {
pipe_buf_release(pipe, buf);
tail++;
}
}
if (tail != pipe->tail) {
pipe->tail = tail;
if (pipe->files)
need_wakeup = true;
}
}
out:
pipe_unlock(pipe);
if (need_wakeup)
wakeup_pipe_writers(pipe);
return spliced ?: ret;
}
#endif
static int warn_unsupported(struct file *file, const char *op)
{
pr_debug_ratelimited(
"splice %s not supported for file %pD4 (pid: %d comm: %.20s)\n",
op, file, current->pid, current->comm);
return -EINVAL;
}
/*
* Attempt to initiate a splice from pipe to file.
*/
static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
if (unlikely(!out->f_op->splice_write))
return warn_unsupported(out, "write");
return out->f_op->splice_write(pipe, out, ppos, len, flags);
}
/*
* Indicate to the caller that there was a premature EOF when reading from the
* source and the caller didn't indicate they would be sending more data after
* this.
*/
static void do_splice_eof(struct splice_desc *sd)
{
if (sd->splice_eof)
sd->splice_eof(sd);
}
/**
* vfs_splice_read - Read data from a file and splice it into a pipe
* @in: File to splice from
* @ppos: Input file offset
* @pipe: Pipe to splice to
* @len: Number of bytes to splice
* @flags: Splice modifier flags (SPLICE_F_*)
*
* Splice the requested amount of data from the input file to the pipe. This
* is synchronous as the caller must hold the pipe lock across the entire
* operation.
*
* If successful, it returns the amount of data spliced, 0 if it hit the EOF or
* a hole and a negative error code otherwise.
*/
long vfs_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
unsigned int p_space;
int ret;
if (unlikely(!(in->f_mode & FMODE_READ)))
return -EBADF;
if (!len)
return 0;
/* Don't try to read more the pipe has space for. */
p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail);
len = min_t(size_t, len, p_space << PAGE_SHIFT);
ret = rw_verify_area(READ, in, ppos, len);
if (unlikely(ret < 0))
return ret;
if (unlikely(len > MAX_RW_COUNT))
len = MAX_RW_COUNT;
if (unlikely(!in->f_op->splice_read))
return warn_unsupported(in, "read");
/*
* O_DIRECT and DAX don't deal with the pagecache, so we allocate a
* buffer, copy into it and splice that into the pipe.
*/
if ((in->f_flags & O_DIRECT) || IS_DAX(in->f_mapping->host))
return copy_splice_read(in, ppos, pipe, len, flags);
return in->f_op->splice_read(in, ppos, pipe, len, flags);
}
EXPORT_SYMBOL_GPL(vfs_splice_read);
/**
* splice_direct_to_actor - splices data directly between two non-pipes
* @in: file to splice from
* @sd: actor information on where to splice to
* @actor: handles the data splicing
*
* Description:
* This is a special case helper to splice directly between two
* points, without requiring an explicit pipe. Internally an allocated
* pipe is cached in the process, and reused during the lifetime of
* that process.
*
*/
ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
splice_direct_actor *actor)
{
struct pipe_inode_info *pipe;
long ret, bytes;
size_t len;
int i, flags, more;
/*
* We require the input to be seekable, as we don't want to randomly
* drop data for eg socket -> socket splicing. Use the piped splicing
* for that!
*/
if (unlikely(!(in->f_mode & FMODE_LSEEK)))
return -EINVAL;
/*
* neither in nor out is a pipe, setup an internal pipe attached to
* 'out' and transfer the wanted data from 'in' to 'out' through that
*/
pipe = current->splice_pipe;
if (unlikely(!pipe)) {
pipe = alloc_pipe_info();
if (!pipe)
return -ENOMEM;
/*
* We don't have an immediate reader, but we'll read the stuff
* out of the pipe right after the splice_to_pipe(). So set
* PIPE_READERS appropriately.
*/
pipe->readers = 1;
current->splice_pipe = pipe;
}
/*
* Do the splice.
*/
bytes = 0;
len = sd->total_len;
/* Don't block on output, we have to drain the direct pipe. */
flags = sd->flags;
sd->flags &= ~SPLICE_F_NONBLOCK;
/*
* We signal MORE until we've read sufficient data to fulfill the
* request and we keep signalling it if the caller set it.
*/
more = sd->flags & SPLICE_F_MORE;
sd->flags |= SPLICE_F_MORE;
WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail));
while (len) {
size_t read_len;
loff_t pos = sd->pos, prev_pos = pos;
ret = vfs_splice_read(in, &pos, pipe, len, flags);
if (unlikely(ret <= 0))
goto read_failure;
read_len = ret;
sd->total_len = read_len;
/*
* If we now have sufficient data to fulfill the request then
* we clear SPLICE_F_MORE if it was not set initially.
*/
if (read_len >= len && !more)
sd->flags &= ~SPLICE_F_MORE;
/*
* NOTE: nonblocking mode only applies to the input. We
* must not do the output in nonblocking mode as then we
* could get stuck data in the internal pipe:
*/
ret = actor(pipe, sd);
if (unlikely(ret <= 0)) {
sd->pos = prev_pos;
goto out_release;
}
bytes += ret;
len -= ret;
sd->pos = pos;
if (ret < read_len) {
sd->pos = prev_pos + ret;
goto out_release;
}
}
done:
pipe->tail = pipe->head = 0;
file_accessed(in);
return bytes;
read_failure:
/*
* If the user did *not* set SPLICE_F_MORE *and* we didn't hit that
* "use all of len" case that cleared SPLICE_F_MORE, *and* we did a
* "->splice_in()" that returned EOF (ie zero) *and* we have sent at
* least 1 byte *then* we will also do the ->splice_eof() call.
*/
if (ret == 0 && !more && len > 0 && bytes)
do_splice_eof(sd);
out_release:
/*
* If we did an incomplete transfer we must release
* the pipe buffers in question:
*/
for (i = 0; i < pipe->ring_size; i++) {
struct pipe_buffer *buf = &pipe->bufs[i];
if (buf->ops)
pipe_buf_release(pipe, buf);
}
if (!bytes)
bytes = ret;
goto done;
}
EXPORT_SYMBOL(splice_direct_to_actor);
static int direct_splice_actor(struct pipe_inode_info *pipe,
struct splice_desc *sd)
{
struct file *file = sd->u.file;
return do_splice_from(pipe, file, sd->opos, sd->total_len,
sd->flags);
}
static void direct_file_splice_eof(struct splice_desc *sd)
{
struct file *file = sd->u.file;
if (file->f_op->splice_eof)
file->f_op->splice_eof(file);
}
/**
* do_splice_direct - splices data directly between two files
* @in: file to splice from
* @ppos: input file offset
* @out: file to splice to
* @opos: output file offset
* @len: number of bytes to splice
* @flags: splice modifier flags
*
* Description:
* For use by do_sendfile(). splice can easily emulate sendfile, but
* doing it in the application would incur an extra system call
* (splice in + splice out, as compared to just sendfile()). So this helper
* can splice directly through a process-private pipe.
*
*/
long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
loff_t *opos, size_t len, unsigned int flags)
{
struct splice_desc sd = {
.len = len,
.total_len = len,
.flags = flags,
.pos = *ppos,
.u.file = out,
.splice_eof = direct_file_splice_eof,
.opos = opos,
};
long ret;
if (unlikely(!(out->f_mode & FMODE_WRITE)))
return -EBADF;
if (unlikely(out->f_flags & O_APPEND))
return -EINVAL;
ret = rw_verify_area(WRITE, out, opos, len);
if (unlikely(ret < 0))
return ret;
ret = splice_direct_to_actor(in, &sd, direct_splice_actor);
if (ret > 0)
*ppos = sd.pos;
return ret;
}
EXPORT_SYMBOL(do_splice_direct);
static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags)
{
for (;;) {
if (unlikely(!pipe->readers)) {
send_sig(SIGPIPE, current, 0);
return -EPIPE;
}
if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage))
return 0;
if (flags & SPLICE_F_NONBLOCK)
return -EAGAIN;
if (signal_pending(current))
return -ERESTARTSYS;
pipe_wait_writable(pipe);
}
}
static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
struct pipe_inode_info *opipe,
size_t len, unsigned int flags);
long splice_file_to_pipe(struct file *in,
struct pipe_inode_info *opipe,
loff_t *offset,
size_t len, unsigned int flags)
{
long ret;
pipe_lock(opipe);
ret = wait_for_space(opipe, flags);
if (!ret)
ret = vfs_splice_read(in, offset, opipe, len, flags);
pipe_unlock(opipe);
if (ret > 0)
wakeup_pipe_readers(opipe);
return ret;
}
/*
* Determine where to splice to/from.
*/
long do_splice(struct file *in, loff_t *off_in, struct file *out,
loff_t *off_out, size_t len, unsigned int flags)
{
struct pipe_inode_info *ipipe;
struct pipe_inode_info *opipe;
loff_t offset;
long ret;
if (unlikely(!(in->f_mode & FMODE_READ) ||
!(out->f_mode & FMODE_WRITE)))
return -EBADF;
ipipe = get_pipe_info(in, true);
opipe = get_pipe_info(out, true);
if (ipipe && opipe) {
if (off_in || off_out)
return -ESPIPE;
/* Splicing to self would be fun, but... */
if (ipipe == opipe)
return -EINVAL;
if ((in->f_flags | out->f_flags) & O_NONBLOCK)
flags |= SPLICE_F_NONBLOCK;
ret = splice_pipe_to_pipe(ipipe, opipe, len, flags);
} else if (ipipe) {
if (off_in)
return -ESPIPE;
if (off_out) {
if (!(out->f_mode & FMODE_PWRITE))
return -EINVAL;
offset = *off_out;
} else {
offset = out->f_pos;
}
if (unlikely(out->f_flags & O_APPEND))
return -EINVAL;
ret = rw_verify_area(WRITE, out, &offset, len);
if (unlikely(ret < 0))
return ret;
if (in->f_flags & O_NONBLOCK)
flags |= SPLICE_F_NONBLOCK;
file_start_write(out);
ret = do_splice_from(ipipe, out, &offset, len, flags);
file_end_write(out);
if (!off_out)
out->f_pos = offset;
else
*off_out = offset;
} else if (opipe) {
if (off_out)
return -ESPIPE;
if (off_in) {
if (!(in->f_mode & FMODE_PREAD))
return -EINVAL;
offset = *off_in;
} else {
offset = in->f_pos;
}
if (out->f_flags & O_NONBLOCK)
flags |= SPLICE_F_NONBLOCK;
ret = splice_file_to_pipe(in, opipe, &offset, len, flags);
if (!off_in)
in->f_pos = offset;
else
*off_in = offset;
} else {
ret = -EINVAL;
}
if (ret > 0) {
/*
* Generate modify out before access in:
* do_splice_from() may've already sent modify out,
* and this ensures the events get merged.
*/
fsnotify_modify(out);
fsnotify_access(in);
}
return ret;
}
static long __do_splice(struct file *in, loff_t __user *off_in,
struct file *out, loff_t __user *off_out,
size_t len, unsigned int flags)
{
struct pipe_inode_info *ipipe;
struct pipe_inode_info *opipe;
loff_t offset, *__off_in = NULL, *__off_out = NULL;
long ret;
ipipe = get_pipe_info(in, true);
opipe = get_pipe_info(out, true);
if (ipipe) {
if (off_in)
return -ESPIPE;
pipe_clear_nowait(in);
}
if (opipe) {
if (off_out)
return -ESPIPE;
pipe_clear_nowait(out);
}
if (off_out) {
if (copy_from_user(&offset, off_out, sizeof(loff_t)))
return -EFAULT;
__off_out = &offset;
}
if (off_in) {
if (copy_from_user(&offset, off_in, sizeof(loff_t)))
return -EFAULT;
__off_in = &offset;
}
ret = do_splice(in, __off_in, out, __off_out, len, flags);
if (ret < 0)
return ret;
if (__off_out && copy_to_user(off_out, __off_out, sizeof(loff_t)))
return -EFAULT;
if (__off_in && copy_to_user(off_in, __off_in, sizeof(loff_t)))
return -EFAULT;
return ret;
}
static int iter_to_pipe(struct iov_iter *from,
struct pipe_inode_info *pipe,
unsigned flags)
{
struct pipe_buffer buf = {
.ops = &user_page_pipe_buf_ops,
.flags = flags
};
size_t total = 0;
int ret = 0;
while (iov_iter_count(from)) {
struct page *pages[16];
ssize_t left;
size_t start;
int i, n;
left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start);
if (left <= 0) {
ret = left;
break;
}
n = DIV_ROUND_UP(left + start, PAGE_SIZE);
for (i = 0; i < n; i++) {
int size = min_t(int, left, PAGE_SIZE - start);
buf.page = pages[i];
buf.offset = start;
buf.len = size;
ret = add_to_pipe(pipe, &buf);
if (unlikely(ret < 0)) {
iov_iter_revert(from, left);
// this one got dropped by add_to_pipe()
while (++i < n)
put_page(pages[i]);
goto out;
}
total += ret;
left -= size;
start = 0;
}
}
out:
return total ? total : ret;
}
static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
struct splice_desc *sd)
{
int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data);
return n == sd->len ? n : -EFAULT;
}
/*
* For lack of a better implementation, implement vmsplice() to userspace
* as a simple copy of the pipes pages to the user iov.
*/
static long vmsplice_to_user(struct file *file, struct iov_iter *iter,
unsigned int flags)
{
struct pipe_inode_info *pipe = get_pipe_info(file, true);
struct splice_desc sd = {
.total_len = iov_iter_count(iter),
.flags = flags,
.u.data = iter
};
long ret = 0;
if (!pipe)
return -EBADF;
pipe_clear_nowait(file);
if (sd.total_len) {
pipe_lock(pipe);
ret = __splice_from_pipe(pipe, &sd, pipe_to_user);
pipe_unlock(pipe);
}
if (ret > 0)
fsnotify_access(file);
return ret;
}
/*
* vmsplice splices a user address range into a pipe. It can be thought of
* as splice-from-memory, where the regular splice is splice-from-file (or
* to file). In both cases the output is a pipe, naturally.
*/
static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter,
unsigned int flags)
{
struct pipe_inode_info *pipe;
long ret = 0;
unsigned buf_flag = 0;
if (flags & SPLICE_F_GIFT)
buf_flag = PIPE_BUF_FLAG_GIFT;
pipe = get_pipe_info(file, true);
if (!pipe)
return -EBADF;
pipe_clear_nowait(file);
pipe_lock(pipe);
ret = wait_for_space(pipe, flags);
if (!ret)
ret = iter_to_pipe(iter, pipe, buf_flag);
pipe_unlock(pipe);
if (ret > 0) {
wakeup_pipe_readers(pipe);
fsnotify_modify(file);
}
return ret;
}
static int vmsplice_type(struct fd f, int *type)
{
if (!f.file)
return -EBADF;
if (f.file->f_mode & FMODE_WRITE) {
*type = ITER_SOURCE;
} else if (f.file->f_mode & FMODE_READ) {
*type = ITER_DEST;
} else {
fdput(f);
return -EBADF;
}
return 0;
}
/*
* Note that vmsplice only really supports true splicing _from_ user memory
* to a pipe, not the other way around. Splicing from user memory is a simple
* operation that can be supported without any funky alignment restrictions
* or nasty vm tricks. We simply map in the user memory and fill them into
* a pipe. The reverse isn't quite as easy, though. There are two possible
* solutions for that:
*
* - memcpy() the data internally, at which point we might as well just
* do a regular read() on the buffer anyway.
* - Lots of nasty vm tricks, that are neither fast nor flexible (it
* has restriction limitations on both ends of the pipe).
*
* Currently we punt and implement it as a normal copy, see pipe_to_user().
*
*/
SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov,
unsigned long, nr_segs, unsigned int, flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
ssize_t error;
struct fd f;
int type;
if (unlikely(flags & ~SPLICE_F_ALL))
return -EINVAL;
f = fdget(fd);
error = vmsplice_type(f, &type);
if (error)
return error;
error = import_iovec(type, uiov, nr_segs,
ARRAY_SIZE(iovstack), &iov, &iter);
if (error < 0)
goto out_fdput;
if (!iov_iter_count(&iter))
error = 0;
else if (type == ITER_SOURCE)
error = vmsplice_to_pipe(f.file, &iter, flags);
else
error = vmsplice_to_user(f.file, &iter, flags);
kfree(iov);
out_fdput:
fdput(f);
return error;
}
SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in,
int, fd_out, loff_t __user *, off_out,
size_t, len, unsigned int, flags)
{
struct fd in, out;
long error;
if (unlikely(!len))
return 0;
if (unlikely(flags & ~SPLICE_F_ALL))
return -EINVAL;
error = -EBADF;
in = fdget(fd_in);
if (in.file) {
out = fdget(fd_out);
if (out.file) {
error = __do_splice(in.file, off_in, out.file, off_out,
len, flags);
fdput(out);
}
fdput(in);
}
return error;
}
/*
* Make sure there's data to read. Wait for input if we can, otherwise
* return an appropriate error.
*/
static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
{
int ret;
/*
* Check the pipe occupancy without the inode lock first. This function
* is speculative anyways, so missing one is ok.
*/
if (!pipe_empty(pipe->head, pipe->tail))
return 0;
ret = 0;
pipe_lock(pipe);
while (pipe_empty(pipe->head, pipe->tail)) {
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
if (!pipe->writers)
break;
if (flags & SPLICE_F_NONBLOCK) {
ret = -EAGAIN;
break;
}
pipe_wait_readable(pipe);
}
pipe_unlock(pipe);
return ret;
}
/*
* Make sure there's writeable room. Wait for room if we can, otherwise
* return an appropriate error.
*/
static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
{
int ret;
/*
* Check pipe occupancy without the inode lock first. This function
* is speculative anyways, so missing one is ok.
*/
if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage))
return 0;
ret = 0;
pipe_lock(pipe);
while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) {
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
break;
}
if (flags & SPLICE_F_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
pipe_wait_writable(pipe);
}
pipe_unlock(pipe);
return ret;
}
/*
* Splice contents of ipipe to opipe.
*/
static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
struct pipe_inode_info *opipe,
size_t len, unsigned int flags)
{
struct pipe_buffer *ibuf, *obuf;
unsigned int i_head, o_head;
unsigned int i_tail, o_tail;
unsigned int i_mask, o_mask;
int ret = 0;
bool input_wakeup = false;
retry:
ret = ipipe_prep(ipipe, flags);
if (ret)
return ret;
ret = opipe_prep(opipe, flags);
if (ret)
return ret;
/*
* Potential ABBA deadlock, work around it by ordering lock
* grabbing by pipe info address. Otherwise two different processes
* could deadlock (one doing tee from A -> B, the other from B -> A).
*/
pipe_double_lock(ipipe, opipe);
i_tail = ipipe->tail;
i_mask = ipipe->ring_size - 1;
o_head = opipe->head;
o_mask = opipe->ring_size - 1;
do {
size_t o_len;
if (!opipe->readers) {
send_sig(SIGPIPE, current, 0);
if (!ret)
ret = -EPIPE;
break;
}
i_head = ipipe->head;
o_tail = opipe->tail;
if (pipe_empty(i_head, i_tail) && !ipipe->writers)
break;
/*
* Cannot make any progress, because either the input
* pipe is empty or the output pipe is full.
*/
if (pipe_empty(i_head, i_tail) ||
pipe_full(o_head, o_tail, opipe->max_usage)) {
/* Already processed some buffers, break */
if (ret)
break;
if (flags & SPLICE_F_NONBLOCK) {
ret = -EAGAIN;
break;
}
/*
* We raced with another reader/writer and haven't
* managed to process any buffers. A zero return
* value means EOF, so retry instead.
*/
pipe_unlock(ipipe);
pipe_unlock(opipe);
goto retry;
}
ibuf = &ipipe->bufs[i_tail & i_mask];
obuf = &opipe->bufs[o_head & o_mask];
if (len >= ibuf->len) {
/*
* Simply move the whole buffer from ipipe to opipe
*/
*obuf = *ibuf;
ibuf->ops = NULL;
i_tail++;
ipipe->tail = i_tail;
input_wakeup = true;
o_len = obuf->len;
o_head++;
opipe->head = o_head;
} else {
/*
* Get a reference to this pipe buffer,
* so we can copy the contents over.
*/
if (!pipe_buf_get(ipipe, ibuf)) {
if (ret == 0)
ret = -EFAULT;
break;
}
*obuf = *ibuf;
/*
* Don't inherit the gift and merge flags, we need to
* prevent multiple steals of this page.
*/
obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE;
obuf->len = len;
ibuf->offset += len;
ibuf->len -= len;
o_len = len;
o_head++;
opipe->head = o_head;
}
ret += o_len;
len -= o_len;
} while (len);
pipe_unlock(ipipe);
pipe_unlock(opipe);
/*
* If we put data in the output pipe, wakeup any potential readers.
*/
if (ret > 0)
wakeup_pipe_readers(opipe);
if (input_wakeup)
wakeup_pipe_writers(ipipe);
return ret;
}
/*
* Link contents of ipipe to opipe.
*/
static int link_pipe(struct pipe_inode_info *ipipe,
struct pipe_inode_info *opipe,
size_t len, unsigned int flags)
{
struct pipe_buffer *ibuf, *obuf;
unsigned int i_head, o_head;
unsigned int i_tail, o_tail;
unsigned int i_mask, o_mask;
int ret = 0;
/*
* Potential ABBA deadlock, work around it by ordering lock
* grabbing by pipe info address. Otherwise two different processes
* could deadlock (one doing tee from A -> B, the other from B -> A).
*/
pipe_double_lock(ipipe, opipe);
i_tail = ipipe->tail;
i_mask = ipipe->ring_size - 1;
o_head = opipe->head;
o_mask = opipe->ring_size - 1;
do {
if (!opipe->readers) {
send_sig(SIGPIPE, current, 0);
if (!ret)
ret = -EPIPE;
break;
}
i_head = ipipe->head;
o_tail = opipe->tail;
/*
* If we have iterated all input buffers or run out of
* output room, break.
*/
if (pipe_empty(i_head, i_tail) ||
pipe_full(o_head, o_tail, opipe->max_usage))
break;
ibuf = &ipipe->bufs[i_tail & i_mask];
obuf = &opipe->bufs[o_head & o_mask];
/*
* Get a reference to this pipe buffer,
* so we can copy the contents over.
*/
if (!pipe_buf_get(ipipe, ibuf)) {
if (ret == 0)
ret = -EFAULT;
break;
}
*obuf = *ibuf;
/*
* Don't inherit the gift and merge flag, we need to prevent
* multiple steals of this page.
*/
obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
obuf->flags &= ~PIPE_BUF_FLAG_CAN_MERGE;
if (obuf->len > len)
obuf->len = len;
ret += obuf->len;
len -= obuf->len;
o_head++;
opipe->head = o_head;
i_tail++;
} while (len);
pipe_unlock(ipipe);
pipe_unlock(opipe);
/*
* If we put data in the output pipe, wakeup any potential readers.
*/
if (ret > 0)
wakeup_pipe_readers(opipe);
return ret;
}
/*
* This is a tee(1) implementation that works on pipes. It doesn't copy
* any data, it simply references the 'in' pages on the 'out' pipe.
* The 'flags' used are the SPLICE_F_* variants, currently the only
* applicable one is SPLICE_F_NONBLOCK.
*/
long do_tee(struct file *in, struct file *out, size_t len, unsigned int flags)
{
struct pipe_inode_info *ipipe = get_pipe_info(in, true);
struct pipe_inode_info *opipe = get_pipe_info(out, true);
int ret = -EINVAL;
if (unlikely(!(in->f_mode & FMODE_READ) ||
!(out->f_mode & FMODE_WRITE)))
return -EBADF;
/*
* Duplicate the contents of ipipe to opipe without actually
* copying the data.
*/
if (ipipe && opipe && ipipe != opipe) {
if ((in->f_flags | out->f_flags) & O_NONBLOCK)
flags |= SPLICE_F_NONBLOCK;
/*
* Keep going, unless we encounter an error. The ipipe/opipe
* ordering doesn't really matter.
*/
ret = ipipe_prep(ipipe, flags);
if (!ret) {
ret = opipe_prep(opipe, flags);
if (!ret)
ret = link_pipe(ipipe, opipe, len, flags);
}
}
if (ret > 0) {
fsnotify_access(in);
fsnotify_modify(out);
}
return ret;
}
SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags)
{
struct fd in, out;
int error;
if (unlikely(flags & ~SPLICE_F_ALL))
return -EINVAL;
if (unlikely(!len))
return 0;
error = -EBADF;
in = fdget(fdin);
if (in.file) {
out = fdget(fdout);
if (out.file) {
error = do_tee(in.file, out.file, len, flags);
fdput(out);
}
fdput(in);
}
return error;
}
| linux-master | fs/splice.c |
// SPDX-License-Identifier: GPL-2.0
/*
* /proc/sys/fs shared sysctls
*
* These sysctls are shared between different filesystems.
*/
#include <linux/init.h>
#include <linux/sysctl.h>
static struct ctl_table fs_shared_sysctls[] = {
{
.procname = "overflowuid",
.data = &fs_overflowuid,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_MAXOLDUID,
},
{
.procname = "overflowgid",
.data = &fs_overflowgid,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_MAXOLDUID,
},
{ }
};
static int __init init_fs_sysctls(void)
{
register_sysctl_init("fs", fs_shared_sysctls);
return 0;
}
early_initcall(init_fs_sysctls);
| linux-master | fs/sysctls.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/utime.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
#include <asm/unistd.h>
#include <linux/filelock.h>
static bool nsec_valid(long nsec)
{
if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
return true;
return nsec >= 0 && nsec <= 999999999;
}
int vfs_utimes(const struct path *path, struct timespec64 *times)
{
int error;
struct iattr newattrs;
struct inode *inode = path->dentry->d_inode;
struct inode *delegated_inode = NULL;
if (times) {
if (!nsec_valid(times[0].tv_nsec) ||
!nsec_valid(times[1].tv_nsec))
return -EINVAL;
if (times[0].tv_nsec == UTIME_NOW &&
times[1].tv_nsec == UTIME_NOW)
times = NULL;
}
error = mnt_want_write(path->mnt);
if (error)
goto out;
newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
if (times) {
if (times[0].tv_nsec == UTIME_OMIT)
newattrs.ia_valid &= ~ATTR_ATIME;
else if (times[0].tv_nsec != UTIME_NOW) {
newattrs.ia_atime = times[0];
newattrs.ia_valid |= ATTR_ATIME_SET;
}
if (times[1].tv_nsec == UTIME_OMIT)
newattrs.ia_valid &= ~ATTR_MTIME;
else if (times[1].tv_nsec != UTIME_NOW) {
newattrs.ia_mtime = times[1];
newattrs.ia_valid |= ATTR_MTIME_SET;
}
/*
* Tell setattr_prepare(), that this is an explicit time
* update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
* were used.
*/
newattrs.ia_valid |= ATTR_TIMES_SET;
} else {
newattrs.ia_valid |= ATTR_TOUCH;
}
retry_deleg:
inode_lock(inode);
error = notify_change(mnt_idmap(path->mnt), path->dentry, &newattrs,
&delegated_inode);
inode_unlock(inode);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
mnt_drop_write(path->mnt);
out:
return error;
}
static int do_utimes_path(int dfd, const char __user *filename,
struct timespec64 *times, int flags)
{
struct path path;
int lookup_flags = 0, error;
if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
return -EINVAL;
if (!(flags & AT_SYMLINK_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
if (flags & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
retry:
error = user_path_at(dfd, filename, lookup_flags, &path);
if (error)
return error;
error = vfs_utimes(&path, times);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
}
static int do_utimes_fd(int fd, struct timespec64 *times, int flags)
{
struct fd f;
int error;
if (flags)
return -EINVAL;
f = fdget(fd);
if (!f.file)
return -EBADF;
error = vfs_utimes(&f.file->f_path, times);
fdput(f);
return error;
}
/*
* do_utimes - change times on filename or file descriptor
* @dfd: open file descriptor, -1 or AT_FDCWD
* @filename: path name or NULL
* @times: new times or NULL
* @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
*
* If filename is NULL and dfd refers to an open file, then operate on
* the file. Otherwise look up filename, possibly using dfd as a
* starting point.
*
* If times==NULL, set access and modification to current time,
* must be owner or have write permission.
* Else, update from *times, must be owner or super user.
*/
long do_utimes(int dfd, const char __user *filename, struct timespec64 *times,
int flags)
{
if (filename == NULL && dfd != AT_FDCWD)
return do_utimes_fd(dfd, times, flags);
return do_utimes_path(dfd, filename, times, flags);
}
SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
struct __kernel_timespec __user *, utimes, int, flags)
{
struct timespec64 tstimes[2];
if (utimes) {
if ((get_timespec64(&tstimes[0], &utimes[0]) ||
get_timespec64(&tstimes[1], &utimes[1])))
return -EFAULT;
/* Nothing to do, we must not even check the path. */
if (tstimes[0].tv_nsec == UTIME_OMIT &&
tstimes[1].tv_nsec == UTIME_OMIT)
return 0;
}
return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
}
#ifdef __ARCH_WANT_SYS_UTIME
/*
* futimesat(), utimes() and utime() are older versions of utimensat()
* that are provided for compatibility with traditional C libraries.
* On modern architectures, we always use libc wrappers around
* utimensat() instead.
*/
static long do_futimesat(int dfd, const char __user *filename,
struct __kernel_old_timeval __user *utimes)
{
struct __kernel_old_timeval times[2];
struct timespec64 tstimes[2];
if (utimes) {
if (copy_from_user(×, utimes, sizeof(times)))
return -EFAULT;
/* This test is needed to catch all invalid values. If we
would test only in do_utimes we would miss those invalid
values truncated by the multiplication with 1000. Note
that we also catch UTIME_{NOW,OMIT} here which are only
valid for utimensat. */
if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
return -EINVAL;
tstimes[0].tv_sec = times[0].tv_sec;
tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
tstimes[1].tv_sec = times[1].tv_sec;
tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
}
return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
}
SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
struct __kernel_old_timeval __user *, utimes)
{
return do_futimesat(dfd, filename, utimes);
}
SYSCALL_DEFINE2(utimes, char __user *, filename,
struct __kernel_old_timeval __user *, utimes)
{
return do_futimesat(AT_FDCWD, filename, utimes);
}
SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
{
struct timespec64 tv[2];
if (times) {
if (get_user(tv[0].tv_sec, ×->actime) ||
get_user(tv[1].tv_sec, ×->modtime))
return -EFAULT;
tv[0].tv_nsec = 0;
tv[1].tv_nsec = 0;
}
return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
}
#endif
#ifdef CONFIG_COMPAT_32BIT_TIME
/*
* Not all architectures have sys_utime, so implement this in terms
* of sys_utimes.
*/
#ifdef __ARCH_WANT_SYS_UTIME32
SYSCALL_DEFINE2(utime32, const char __user *, filename,
struct old_utimbuf32 __user *, t)
{
struct timespec64 tv[2];
if (t) {
if (get_user(tv[0].tv_sec, &t->actime) ||
get_user(tv[1].tv_sec, &t->modtime))
return -EFAULT;
tv[0].tv_nsec = 0;
tv[1].tv_nsec = 0;
}
return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
}
#endif
SYSCALL_DEFINE4(utimensat_time32, unsigned int, dfd, const char __user *, filename, struct old_timespec32 __user *, t, int, flags)
{
struct timespec64 tv[2];
if (t) {
if (get_old_timespec32(&tv[0], &t[0]) ||
get_old_timespec32(&tv[1], &t[1]))
return -EFAULT;
if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
return 0;
}
return do_utimes(dfd, filename, t ? tv : NULL, flags);
}
#ifdef __ARCH_WANT_SYS_UTIME32
static long do_compat_futimesat(unsigned int dfd, const char __user *filename,
struct old_timeval32 __user *t)
{
struct timespec64 tv[2];
if (t) {
if (get_user(tv[0].tv_sec, &t[0].tv_sec) ||
get_user(tv[0].tv_nsec, &t[0].tv_usec) ||
get_user(tv[1].tv_sec, &t[1].tv_sec) ||
get_user(tv[1].tv_nsec, &t[1].tv_usec))
return -EFAULT;
if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 ||
tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0)
return -EINVAL;
tv[0].tv_nsec *= 1000;
tv[1].tv_nsec *= 1000;
}
return do_utimes(dfd, filename, t ? tv : NULL, 0);
}
SYSCALL_DEFINE3(futimesat_time32, unsigned int, dfd,
const char __user *, filename,
struct old_timeval32 __user *, t)
{
return do_compat_futimesat(dfd, filename, t);
}
SYSCALL_DEFINE2(utimes_time32, const char __user *, filename, struct old_timeval32 __user *, t)
{
return do_compat_futimesat(AT_FDCWD, filename, t);
}
#endif
#endif
| linux-master | fs/utimes.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* 32-bit compatibility support for ELF format executables and core dumps.
*
* Copyright (C) 2007 Red Hat, Inc. All rights reserved.
*
* Red Hat Author: Roland McGrath.
*
* This file is used in a 64-bit kernel that wants to support 32-bit ELF.
* asm/elf.h is responsible for defining the compat_* and COMPAT_* macros
* used below, with definitions appropriate for 32-bit ABI compatibility.
*
* We use macros to rename the ABI types and machine-dependent
* functions used in binfmt_elf.c to compat versions.
*/
#include <linux/elfcore-compat.h>
#include <linux/time.h>
#define ELF_COMPAT 1
/*
* Rename the basic ELF layout types to refer to the 32-bit class of files.
*/
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
#undef elfhdr
#undef elf_phdr
#undef elf_shdr
#undef elf_note
#undef elf_addr_t
#undef ELF_GNU_PROPERTY_ALIGN
#define elfhdr elf32_hdr
#define elf_phdr elf32_phdr
#define elf_shdr elf32_shdr
#define elf_note elf32_note
#define elf_addr_t Elf32_Addr
#define ELF_GNU_PROPERTY_ALIGN ELF32_GNU_PROPERTY_ALIGN
/*
* Some data types as stored in coredump.
*/
#define user_long_t compat_long_t
#define user_siginfo_t compat_siginfo_t
#define copy_siginfo_to_external copy_siginfo_to_external32
/*
* The machine-dependent core note format types are defined in elfcore-compat.h,
* which requires asm/elf.h to define compat_elf_gregset_t et al.
*/
#define elf_prstatus compat_elf_prstatus
#define elf_prstatus_common compat_elf_prstatus_common
#define elf_prpsinfo compat_elf_prpsinfo
#undef ns_to_kernel_old_timeval
#define ns_to_kernel_old_timeval ns_to_old_timeval32
/*
* To use this file, asm/elf.h must define compat_elf_check_arch.
* The other following macros can be defined if the compat versions
* differ from the native ones, or omitted when they match.
*/
#undef elf_check_arch
#define elf_check_arch compat_elf_check_arch
#ifdef COMPAT_ELF_PLATFORM
#undef ELF_PLATFORM
#define ELF_PLATFORM COMPAT_ELF_PLATFORM
#endif
#ifdef COMPAT_ELF_HWCAP
#undef ELF_HWCAP
#define ELF_HWCAP COMPAT_ELF_HWCAP
#endif
#ifdef COMPAT_ELF_HWCAP2
#undef ELF_HWCAP2
#define ELF_HWCAP2 COMPAT_ELF_HWCAP2
#endif
#ifdef COMPAT_ARCH_DLINFO
#undef ARCH_DLINFO
#define ARCH_DLINFO COMPAT_ARCH_DLINFO
#endif
#ifdef COMPAT_ELF_ET_DYN_BASE
#undef ELF_ET_DYN_BASE
#define ELF_ET_DYN_BASE COMPAT_ELF_ET_DYN_BASE
#endif
#ifdef COMPAT_ELF_PLAT_INIT
#undef ELF_PLAT_INIT
#define ELF_PLAT_INIT COMPAT_ELF_PLAT_INIT
#endif
#ifdef COMPAT_SET_PERSONALITY
#undef SET_PERSONALITY
#define SET_PERSONALITY COMPAT_SET_PERSONALITY
#endif
#ifdef compat_start_thread
#define COMPAT_START_THREAD(ex, regs, new_ip, new_sp) \
compat_start_thread(regs, new_ip, new_sp)
#endif
#ifdef COMPAT_START_THREAD
#undef START_THREAD
#define START_THREAD COMPAT_START_THREAD
#endif
#ifdef compat_arch_setup_additional_pages
#define COMPAT_ARCH_SETUP_ADDITIONAL_PAGES(bprm, ex, interpreter) \
compat_arch_setup_additional_pages(bprm, interpreter)
#endif
#ifdef COMPAT_ARCH_SETUP_ADDITIONAL_PAGES
#undef ARCH_HAS_SETUP_ADDITIONAL_PAGES
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
#undef ARCH_SETUP_ADDITIONAL_PAGES
#define ARCH_SETUP_ADDITIONAL_PAGES COMPAT_ARCH_SETUP_ADDITIONAL_PAGES
#endif
#ifdef compat_elf_read_implies_exec
#undef elf_read_implies_exec
#define elf_read_implies_exec compat_elf_read_implies_exec
#endif
/*
* Rename a few of the symbols that binfmt_elf.c will define.
* These are all local so the names don't really matter, but it
* might make some debugging less confusing not to duplicate them.
*/
#define elf_format compat_elf_format
#define init_elf_binfmt init_compat_elf_binfmt
#define exit_elf_binfmt exit_compat_elf_binfmt
#define binfmt_elf_test_cases compat_binfmt_elf_test_cases
#define binfmt_elf_test_suite compat_binfmt_elf_test_suite
/*
* We share all the actual code with the native (64-bit) version.
*/
#include "binfmt_elf.c"
| linux-master | fs/compat_binfmt_elf.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
File: fs/xattr.c
Extended attribute handling.
Copyright (C) 2001 by Andreas Gruenbacher <[email protected]>
Copyright (C) 2001 SGI - Silicon Graphics, Inc <[email protected]>
Copyright (c) 2004 Red Hat, Inc., James Morris <[email protected]>
*/
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/xattr.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/evm.h>
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fsnotify.h>
#include <linux/audit.h>
#include <linux/vmalloc.h>
#include <linux/posix_acl_xattr.h>
#include <linux/uaccess.h>
#include "internal.h"
static const char *
strcmp_prefix(const char *a, const char *a_prefix)
{
while (*a_prefix && *a == *a_prefix) {
a++;
a_prefix++;
}
return *a_prefix ? NULL : a;
}
/*
* In order to implement different sets of xattr operations for each xattr
* prefix, a filesystem should create a null-terminated array of struct
* xattr_handler (one for each prefix) and hang a pointer to it off of the
* s_xattr field of the superblock.
*/
#define for_each_xattr_handler(handlers, handler) \
if (handlers) \
for ((handler) = *(handlers)++; \
(handler) != NULL; \
(handler) = *(handlers)++)
/*
* Find the xattr_handler with the matching prefix.
*/
static const struct xattr_handler *
xattr_resolve_name(struct inode *inode, const char **name)
{
const struct xattr_handler **handlers = inode->i_sb->s_xattr;
const struct xattr_handler *handler;
if (!(inode->i_opflags & IOP_XATTR)) {
if (unlikely(is_bad_inode(inode)))
return ERR_PTR(-EIO);
return ERR_PTR(-EOPNOTSUPP);
}
for_each_xattr_handler(handlers, handler) {
const char *n;
n = strcmp_prefix(*name, xattr_prefix(handler));
if (n) {
if (!handler->prefix ^ !*n) {
if (*n)
continue;
return ERR_PTR(-EINVAL);
}
*name = n;
return handler;
}
}
return ERR_PTR(-EOPNOTSUPP);
}
/**
* may_write_xattr - check whether inode allows writing xattr
* @idmap: idmap of the mount the inode was found from
* @inode: the inode on which to set an xattr
*
* Check whether the inode allows writing xattrs. Specifically, we can never
* set or remove an extended attribute on a read-only filesystem or on an
* immutable / append-only inode.
*
* We also need to ensure that the inode has a mapping in the mount to
* not risk writing back invalid i_{g,u}id values.
*
* Return: On success zero is returned. On error a negative errno is returned.
*/
int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode)
{
if (IS_IMMUTABLE(inode))
return -EPERM;
if (IS_APPEND(inode))
return -EPERM;
if (HAS_UNMAPPED_ID(idmap, inode))
return -EPERM;
return 0;
}
/*
* Check permissions for extended attribute access. This is a bit complicated
* because different namespaces have very different rules.
*/
static int
xattr_permission(struct mnt_idmap *idmap, struct inode *inode,
const char *name, int mask)
{
if (mask & MAY_WRITE) {
int ret;
ret = may_write_xattr(idmap, inode);
if (ret)
return ret;
}
/*
* No restriction for security.* and system.* from the VFS. Decision
* on these is left to the underlying filesystem / security module.
*/
if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
return 0;
/*
* The trusted.* namespace can only be accessed by privileged users.
*/
if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
if (!capable(CAP_SYS_ADMIN))
return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
return 0;
}
/*
* In the user.* namespace, only regular files and directories can have
* extended attributes. For sticky directories, only the owner and
* privileged users can write attributes.
*/
if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
(mask & MAY_WRITE) &&
!inode_owner_or_capable(idmap, inode))
return -EPERM;
}
return inode_permission(idmap, inode, mask);
}
/*
* Look for any handler that deals with the specified namespace.
*/
int
xattr_supports_user_prefix(struct inode *inode)
{
const struct xattr_handler **handlers = inode->i_sb->s_xattr;
const struct xattr_handler *handler;
if (!(inode->i_opflags & IOP_XATTR)) {
if (unlikely(is_bad_inode(inode)))
return -EIO;
return -EOPNOTSUPP;
}
for_each_xattr_handler(handlers, handler) {
if (!strncmp(xattr_prefix(handler), XATTR_USER_PREFIX,
XATTR_USER_PREFIX_LEN))
return 0;
}
return -EOPNOTSUPP;
}
EXPORT_SYMBOL(xattr_supports_user_prefix);
int
__vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct inode *inode, const char *name, const void *value,
size_t size, int flags)
{
const struct xattr_handler *handler;
if (is_posix_acl_xattr(name))
return -EOPNOTSUPP;
handler = xattr_resolve_name(inode, &name);
if (IS_ERR(handler))
return PTR_ERR(handler);
if (!handler->set)
return -EOPNOTSUPP;
if (size == 0)
value = ""; /* empty EA, do not remove */
return handler->set(handler, idmap, dentry, inode, name, value,
size, flags);
}
EXPORT_SYMBOL(__vfs_setxattr);
/**
* __vfs_setxattr_noperm - perform setxattr operation without performing
* permission checks.
*
* @idmap: idmap of the mount the inode was found from
* @dentry: object to perform setxattr on
* @name: xattr name to set
* @value: value to set @name to
* @size: size of @value
* @flags: flags to pass into filesystem operations
*
* returns the result of the internal setxattr or setsecurity operations.
*
* This function requires the caller to lock the inode's i_mutex before it
* is executed. It also assumes that the caller will make the appropriate
* permission checks.
*/
int __vfs_setxattr_noperm(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
struct inode *inode = dentry->d_inode;
int error = -EAGAIN;
int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
XATTR_SECURITY_PREFIX_LEN);
if (issec)
inode->i_flags &= ~S_NOSEC;
if (inode->i_opflags & IOP_XATTR) {
error = __vfs_setxattr(idmap, dentry, inode, name, value,
size, flags);
if (!error) {
fsnotify_xattr(dentry);
security_inode_post_setxattr(dentry, name, value,
size, flags);
}
} else {
if (unlikely(is_bad_inode(inode)))
return -EIO;
}
if (error == -EAGAIN) {
error = -EOPNOTSUPP;
if (issec) {
const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
error = security_inode_setsecurity(inode, suffix, value,
size, flags);
if (!error)
fsnotify_xattr(dentry);
}
}
return error;
}
/**
* __vfs_setxattr_locked - set an extended attribute while holding the inode
* lock
*
* @idmap: idmap of the mount of the target inode
* @dentry: object to perform setxattr on
* @name: xattr name to set
* @value: value to set @name to
* @size: size of @value
* @flags: flags to pass into filesystem operations
* @delegated_inode: on return, will contain an inode pointer that
* a delegation was broken on, NULL if none.
*/
int
__vfs_setxattr_locked(struct mnt_idmap *idmap, struct dentry *dentry,
const char *name, const void *value, size_t size,
int flags, struct inode **delegated_inode)
{
struct inode *inode = dentry->d_inode;
int error;
error = xattr_permission(idmap, inode, name, MAY_WRITE);
if (error)
return error;
error = security_inode_setxattr(idmap, dentry, name, value, size,
flags);
if (error)
goto out;
error = try_break_deleg(inode, delegated_inode);
if (error)
goto out;
error = __vfs_setxattr_noperm(idmap, dentry, name, value,
size, flags);
out:
return error;
}
EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
int
vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
const char *name, const void *value, size_t size, int flags)
{
struct inode *inode = dentry->d_inode;
struct inode *delegated_inode = NULL;
const void *orig_value = value;
int error;
if (size && strcmp(name, XATTR_NAME_CAPS) == 0) {
error = cap_convert_nscap(idmap, dentry, &value, size);
if (error < 0)
return error;
size = error;
}
retry_deleg:
inode_lock(inode);
error = __vfs_setxattr_locked(idmap, dentry, name, value, size,
flags, &delegated_inode);
inode_unlock(inode);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
if (value != orig_value)
kfree(value);
return error;
}
EXPORT_SYMBOL_GPL(vfs_setxattr);
static ssize_t
xattr_getsecurity(struct mnt_idmap *idmap, struct inode *inode,
const char *name, void *value, size_t size)
{
void *buffer = NULL;
ssize_t len;
if (!value || !size) {
len = security_inode_getsecurity(idmap, inode, name,
&buffer, false);
goto out_noalloc;
}
len = security_inode_getsecurity(idmap, inode, name, &buffer,
true);
if (len < 0)
return len;
if (size < len) {
len = -ERANGE;
goto out;
}
memcpy(value, buffer, len);
out:
kfree(buffer);
out_noalloc:
return len;
}
/*
* vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
*
* Allocate memory, if not already allocated, or re-allocate correct size,
* before retrieving the extended attribute. The xattr value buffer should
* always be freed by the caller, even on error.
*
* Returns the result of alloc, if failed, or the getxattr operation.
*/
int
vfs_getxattr_alloc(struct mnt_idmap *idmap, struct dentry *dentry,
const char *name, char **xattr_value, size_t xattr_size,
gfp_t flags)
{
const struct xattr_handler *handler;
struct inode *inode = dentry->d_inode;
char *value = *xattr_value;
int error;
error = xattr_permission(idmap, inode, name, MAY_READ);
if (error)
return error;
handler = xattr_resolve_name(inode, &name);
if (IS_ERR(handler))
return PTR_ERR(handler);
if (!handler->get)
return -EOPNOTSUPP;
error = handler->get(handler, dentry, inode, name, NULL, 0);
if (error < 0)
return error;
if (!value || (error > xattr_size)) {
value = krealloc(*xattr_value, error + 1, flags);
if (!value)
return -ENOMEM;
memset(value, 0, error + 1);
}
error = handler->get(handler, dentry, inode, name, value, error);
*xattr_value = value;
return error;
}
ssize_t
__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
void *value, size_t size)
{
const struct xattr_handler *handler;
if (is_posix_acl_xattr(name))
return -EOPNOTSUPP;
handler = xattr_resolve_name(inode, &name);
if (IS_ERR(handler))
return PTR_ERR(handler);
if (!handler->get)
return -EOPNOTSUPP;
return handler->get(handler, dentry, inode, name, value, size);
}
EXPORT_SYMBOL(__vfs_getxattr);
ssize_t
vfs_getxattr(struct mnt_idmap *idmap, struct dentry *dentry,
const char *name, void *value, size_t size)
{
struct inode *inode = dentry->d_inode;
int error;
error = xattr_permission(idmap, inode, name, MAY_READ);
if (error)
return error;
error = security_inode_getxattr(dentry, name);
if (error)
return error;
if (!strncmp(name, XATTR_SECURITY_PREFIX,
XATTR_SECURITY_PREFIX_LEN)) {
const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
int ret = xattr_getsecurity(idmap, inode, suffix, value,
size);
/*
* Only overwrite the return value if a security module
* is actually active.
*/
if (ret == -EOPNOTSUPP)
goto nolsm;
return ret;
}
nolsm:
return __vfs_getxattr(dentry, inode, name, value, size);
}
EXPORT_SYMBOL_GPL(vfs_getxattr);
/**
* vfs_listxattr - retrieve \0 separated list of xattr names
* @dentry: the dentry from whose inode the xattr names are retrieved
* @list: buffer to store xattr names into
* @size: size of the buffer
*
* This function returns the names of all xattrs associated with the
* inode of @dentry.
*
* Note, for legacy reasons the vfs_listxattr() function lists POSIX
* ACLs as well. Since POSIX ACLs are decoupled from IOP_XATTR the
* vfs_listxattr() function doesn't check for this flag since a
* filesystem could implement POSIX ACLs without implementing any other
* xattrs.
*
* However, since all codepaths that remove IOP_XATTR also assign of
* inode operations that either don't implement or implement a stub
* ->listxattr() operation.
*
* Return: On success, the size of the buffer that was used. On error a
* negative error code.
*/
ssize_t
vfs_listxattr(struct dentry *dentry, char *list, size_t size)
{
struct inode *inode = d_inode(dentry);
ssize_t error;
error = security_inode_listxattr(dentry);
if (error)
return error;
if (inode->i_op->listxattr) {
error = inode->i_op->listxattr(dentry, list, size);
} else {
error = security_inode_listsecurity(inode, list, size);
if (size && error > size)
error = -ERANGE;
}
return error;
}
EXPORT_SYMBOL_GPL(vfs_listxattr);
int
__vfs_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
const char *name)
{
struct inode *inode = d_inode(dentry);
const struct xattr_handler *handler;
if (is_posix_acl_xattr(name))
return -EOPNOTSUPP;
handler = xattr_resolve_name(inode, &name);
if (IS_ERR(handler))
return PTR_ERR(handler);
if (!handler->set)
return -EOPNOTSUPP;
return handler->set(handler, idmap, dentry, inode, name, NULL, 0,
XATTR_REPLACE);
}
EXPORT_SYMBOL(__vfs_removexattr);
/**
* __vfs_removexattr_locked - set an extended attribute while holding the inode
* lock
*
* @idmap: idmap of the mount of the target inode
* @dentry: object to perform setxattr on
* @name: name of xattr to remove
* @delegated_inode: on return, will contain an inode pointer that
* a delegation was broken on, NULL if none.
*/
int
__vfs_removexattr_locked(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name,
struct inode **delegated_inode)
{
struct inode *inode = dentry->d_inode;
int error;
error = xattr_permission(idmap, inode, name, MAY_WRITE);
if (error)
return error;
error = security_inode_removexattr(idmap, dentry, name);
if (error)
goto out;
error = try_break_deleg(inode, delegated_inode);
if (error)
goto out;
error = __vfs_removexattr(idmap, dentry, name);
if (!error) {
fsnotify_xattr(dentry);
evm_inode_post_removexattr(dentry, name);
}
out:
return error;
}
EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
int
vfs_removexattr(struct mnt_idmap *idmap, struct dentry *dentry,
const char *name)
{
struct inode *inode = dentry->d_inode;
struct inode *delegated_inode = NULL;
int error;
retry_deleg:
inode_lock(inode);
error = __vfs_removexattr_locked(idmap, dentry,
name, &delegated_inode);
inode_unlock(inode);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
return error;
}
EXPORT_SYMBOL_GPL(vfs_removexattr);
/*
* Extended attribute SET operations
*/
int setxattr_copy(const char __user *name, struct xattr_ctx *ctx)
{
int error;
if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE))
return -EINVAL;
error = strncpy_from_user(ctx->kname->name, name,
sizeof(ctx->kname->name));
if (error == 0 || error == sizeof(ctx->kname->name))
return -ERANGE;
if (error < 0)
return error;
error = 0;
if (ctx->size) {
if (ctx->size > XATTR_SIZE_MAX)
return -E2BIG;
ctx->kvalue = vmemdup_user(ctx->cvalue, ctx->size);
if (IS_ERR(ctx->kvalue)) {
error = PTR_ERR(ctx->kvalue);
ctx->kvalue = NULL;
}
}
return error;
}
int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct xattr_ctx *ctx)
{
if (is_posix_acl_xattr(ctx->kname->name))
return do_set_acl(idmap, dentry, ctx->kname->name,
ctx->kvalue, ctx->size);
return vfs_setxattr(idmap, dentry, ctx->kname->name,
ctx->kvalue, ctx->size, ctx->flags);
}
static long
setxattr(struct mnt_idmap *idmap, struct dentry *d,
const char __user *name, const void __user *value, size_t size,
int flags)
{
struct xattr_name kname;
struct xattr_ctx ctx = {
.cvalue = value,
.kvalue = NULL,
.size = size,
.kname = &kname,
.flags = flags,
};
int error;
error = setxattr_copy(name, &ctx);
if (error)
return error;
error = do_setxattr(idmap, d, &ctx);
kvfree(ctx.kvalue);
return error;
}
static int path_setxattr(const char __user *pathname,
const char __user *name, const void __user *value,
size_t size, int flags, unsigned int lookup_flags)
{
struct path path;
int error;
retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
if (error)
return error;
error = mnt_want_write(path.mnt);
if (!error) {
error = setxattr(mnt_idmap(path.mnt), path.dentry, name,
value, size, flags);
mnt_drop_write(path.mnt);
}
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
}
SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
const char __user *, name, const void __user *, value,
size_t, size, int, flags)
{
return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
}
SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
const char __user *, name, const void __user *, value,
size_t, size, int, flags)
{
return path_setxattr(pathname, name, value, size, flags, 0);
}
SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
const void __user *,value, size_t, size, int, flags)
{
struct fd f = fdget(fd);
int error = -EBADF;
if (!f.file)
return error;
audit_file(f.file);
error = mnt_want_write_file(f.file);
if (!error) {
error = setxattr(file_mnt_idmap(f.file),
f.file->f_path.dentry, name,
value, size, flags);
mnt_drop_write_file(f.file);
}
fdput(f);
return error;
}
/*
* Extended attribute GET operations
*/
ssize_t
do_getxattr(struct mnt_idmap *idmap, struct dentry *d,
struct xattr_ctx *ctx)
{
ssize_t error;
char *kname = ctx->kname->name;
if (ctx->size) {
if (ctx->size > XATTR_SIZE_MAX)
ctx->size = XATTR_SIZE_MAX;
ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL);
if (!ctx->kvalue)
return -ENOMEM;
}
if (is_posix_acl_xattr(ctx->kname->name))
error = do_get_acl(idmap, d, kname, ctx->kvalue, ctx->size);
else
error = vfs_getxattr(idmap, d, kname, ctx->kvalue, ctx->size);
if (error > 0) {
if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error))
error = -EFAULT;
} else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) {
/* The file system tried to returned a value bigger
than XATTR_SIZE_MAX bytes. Not possible. */
error = -E2BIG;
}
return error;
}
static ssize_t
getxattr(struct mnt_idmap *idmap, struct dentry *d,
const char __user *name, void __user *value, size_t size)
{
ssize_t error;
struct xattr_name kname;
struct xattr_ctx ctx = {
.value = value,
.kvalue = NULL,
.size = size,
.kname = &kname,
.flags = 0,
};
error = strncpy_from_user(kname.name, name, sizeof(kname.name));
if (error == 0 || error == sizeof(kname.name))
error = -ERANGE;
if (error < 0)
return error;
error = do_getxattr(idmap, d, &ctx);
kvfree(ctx.kvalue);
return error;
}
static ssize_t path_getxattr(const char __user *pathname,
const char __user *name, void __user *value,
size_t size, unsigned int lookup_flags)
{
struct path path;
ssize_t error;
retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
if (error)
return error;
error = getxattr(mnt_idmap(path.mnt), path.dentry, name, value, size);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
}
SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
const char __user *, name, void __user *, value, size_t, size)
{
return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
}
SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
const char __user *, name, void __user *, value, size_t, size)
{
return path_getxattr(pathname, name, value, size, 0);
}
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
void __user *, value, size_t, size)
{
struct fd f = fdget(fd);
ssize_t error = -EBADF;
if (!f.file)
return error;
audit_file(f.file);
error = getxattr(file_mnt_idmap(f.file), f.file->f_path.dentry,
name, value, size);
fdput(f);
return error;
}
/*
* Extended attribute LIST operations
*/
static ssize_t
listxattr(struct dentry *d, char __user *list, size_t size)
{
ssize_t error;
char *klist = NULL;
if (size) {
if (size > XATTR_LIST_MAX)
size = XATTR_LIST_MAX;
klist = kvmalloc(size, GFP_KERNEL);
if (!klist)
return -ENOMEM;
}
error = vfs_listxattr(d, klist, size);
if (error > 0) {
if (size && copy_to_user(list, klist, error))
error = -EFAULT;
} else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
/* The file system tried to returned a list bigger
than XATTR_LIST_MAX bytes. Not possible. */
error = -E2BIG;
}
kvfree(klist);
return error;
}
static ssize_t path_listxattr(const char __user *pathname, char __user *list,
size_t size, unsigned int lookup_flags)
{
struct path path;
ssize_t error;
retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
if (error)
return error;
error = listxattr(path.dentry, list, size);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
}
SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
size_t, size)
{
return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
}
SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
size_t, size)
{
return path_listxattr(pathname, list, size, 0);
}
SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
{
struct fd f = fdget(fd);
ssize_t error = -EBADF;
if (!f.file)
return error;
audit_file(f.file);
error = listxattr(f.file->f_path.dentry, list, size);
fdput(f);
return error;
}
/*
* Extended attribute REMOVE operations
*/
static long
removexattr(struct mnt_idmap *idmap, struct dentry *d,
const char __user *name)
{
int error;
char kname[XATTR_NAME_MAX + 1];
error = strncpy_from_user(kname, name, sizeof(kname));
if (error == 0 || error == sizeof(kname))
error = -ERANGE;
if (error < 0)
return error;
if (is_posix_acl_xattr(kname))
return vfs_remove_acl(idmap, d, kname);
return vfs_removexattr(idmap, d, kname);
}
static int path_removexattr(const char __user *pathname,
const char __user *name, unsigned int lookup_flags)
{
struct path path;
int error;
retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
if (error)
return error;
error = mnt_want_write(path.mnt);
if (!error) {
error = removexattr(mnt_idmap(path.mnt), path.dentry, name);
mnt_drop_write(path.mnt);
}
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
}
SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
const char __user *, name)
{
return path_removexattr(pathname, name, LOOKUP_FOLLOW);
}
SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
const char __user *, name)
{
return path_removexattr(pathname, name, 0);
}
SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
{
struct fd f = fdget(fd);
int error = -EBADF;
if (!f.file)
return error;
audit_file(f.file);
error = mnt_want_write_file(f.file);
if (!error) {
error = removexattr(file_mnt_idmap(f.file),
f.file->f_path.dentry, name);
mnt_drop_write_file(f.file);
}
fdput(f);
return error;
}
int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name)
{
size_t len;
len = strlen(name) + 1;
if (*buffer) {
if (*remaining_size < len)
return -ERANGE;
memcpy(*buffer, name, len);
*buffer += len;
}
*remaining_size -= len;
return 0;
}
/**
* generic_listxattr - run through a dentry's xattr list() operations
* @dentry: dentry to list the xattrs
* @buffer: result buffer
* @buffer_size: size of @buffer
*
* Combine the results of the list() operation from every xattr_handler in the
* xattr_handler stack.
*
* Note that this will not include the entries for POSIX ACLs.
*/
ssize_t
generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
ssize_t remaining_size = buffer_size;
int err = 0;
for_each_xattr_handler(handlers, handler) {
if (!handler->name || (handler->list && !handler->list(dentry)))
continue;
err = xattr_list_one(&buffer, &remaining_size, handler->name);
if (err)
return err;
}
return err ? err : buffer_size - remaining_size;
}
EXPORT_SYMBOL(generic_listxattr);
/**
* xattr_full_name - Compute full attribute name from suffix
*
* @handler: handler of the xattr_handler operation
* @name: name passed to the xattr_handler operation
*
* The get and set xattr handler operations are called with the remainder of
* the attribute name after skipping the handler's prefix: for example, "foo"
* is passed to the get operation of a handler with prefix "user." to get
* attribute "user.foo". The full name is still "there" in the name though.
*
* Note: the list xattr handler operation when called from the vfs is passed a
* NULL name; some file systems use this operation internally, with varying
* semantics.
*/
const char *xattr_full_name(const struct xattr_handler *handler,
const char *name)
{
size_t prefix_len = strlen(xattr_prefix(handler));
return name - prefix_len;
}
EXPORT_SYMBOL(xattr_full_name);
/**
* simple_xattr_space - estimate the memory used by a simple xattr
* @name: the full name of the xattr
* @size: the size of its value
*
* This takes no account of how much larger the two slab objects actually are:
* that would depend on the slab implementation, when what is required is a
* deterministic number, which grows with name length and size and quantity.
*
* Return: The approximate number of bytes of memory used by such an xattr.
*/
size_t simple_xattr_space(const char *name, size_t size)
{
/*
* Use "40" instead of sizeof(struct simple_xattr), to return the
* same result on 32-bit and 64-bit, and even if simple_xattr grows.
*/
return 40 + size + strlen(name);
}
/**
* simple_xattr_free - free an xattr object
* @xattr: the xattr object
*
* Free the xattr object. Can handle @xattr being NULL.
*/
void simple_xattr_free(struct simple_xattr *xattr)
{
if (xattr)
kfree(xattr->name);
kvfree(xattr);
}
/**
* simple_xattr_alloc - allocate new xattr object
* @value: value of the xattr object
* @size: size of @value
*
* Allocate a new xattr object and initialize respective members. The caller is
* responsible for handling the name of the xattr.
*
* Return: On success a new xattr object is returned. On failure NULL is
* returned.
*/
struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
{
struct simple_xattr *new_xattr;
size_t len;
/* wrap around? */
len = sizeof(*new_xattr) + size;
if (len < sizeof(*new_xattr))
return NULL;
new_xattr = kvmalloc(len, GFP_KERNEL_ACCOUNT);
if (!new_xattr)
return NULL;
new_xattr->size = size;
memcpy(new_xattr->value, value, size);
return new_xattr;
}
/**
* rbtree_simple_xattr_cmp - compare xattr name with current rbtree xattr entry
* @key: xattr name
* @node: current node
*
* Compare the xattr name with the xattr name attached to @node in the rbtree.
*
* Return: Negative value if continuing left, positive if continuing right, 0
* if the xattr attached to @node matches @key.
*/
static int rbtree_simple_xattr_cmp(const void *key, const struct rb_node *node)
{
const char *xattr_name = key;
const struct simple_xattr *xattr;
xattr = rb_entry(node, struct simple_xattr, rb_node);
return strcmp(xattr->name, xattr_name);
}
/**
* rbtree_simple_xattr_node_cmp - compare two xattr rbtree nodes
* @new_node: new node
* @node: current node
*
* Compare the xattr attached to @new_node with the xattr attached to @node.
*
* Return: Negative value if continuing left, positive if continuing right, 0
* if the xattr attached to @new_node matches the xattr attached to @node.
*/
static int rbtree_simple_xattr_node_cmp(struct rb_node *new_node,
const struct rb_node *node)
{
struct simple_xattr *xattr;
xattr = rb_entry(new_node, struct simple_xattr, rb_node);
return rbtree_simple_xattr_cmp(xattr->name, node);
}
/**
* simple_xattr_get - get an xattr object
* @xattrs: the header of the xattr object
* @name: the name of the xattr to retrieve
* @buffer: the buffer to store the value into
* @size: the size of @buffer
*
* Try to find and retrieve the xattr object associated with @name.
* If @buffer is provided store the value of @xattr in @buffer
* otherwise just return the length. The size of @buffer is limited
* to XATTR_SIZE_MAX which currently is 65536.
*
* Return: On success the length of the xattr value is returned. On error a
* negative error code is returned.
*/
int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
void *buffer, size_t size)
{
struct simple_xattr *xattr = NULL;
struct rb_node *rbp;
int ret = -ENODATA;
read_lock(&xattrs->lock);
rbp = rb_find(name, &xattrs->rb_root, rbtree_simple_xattr_cmp);
if (rbp) {
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
ret = xattr->size;
if (buffer) {
if (size < xattr->size)
ret = -ERANGE;
else
memcpy(buffer, xattr->value, xattr->size);
}
}
read_unlock(&xattrs->lock);
return ret;
}
/**
* simple_xattr_set - set an xattr object
* @xattrs: the header of the xattr object
* @name: the name of the xattr to retrieve
* @value: the value to store along the xattr
* @size: the size of @value
* @flags: the flags determining how to set the xattr
*
* Set a new xattr object.
* If @value is passed a new xattr object will be allocated. If XATTR_REPLACE
* is specified in @flags a matching xattr object for @name must already exist.
* If it does it will be replaced with the new xattr object. If it doesn't we
* fail. If XATTR_CREATE is specified and a matching xattr does already exist
* we fail. If it doesn't we create a new xattr. If @flags is zero we simply
* insert the new xattr replacing any existing one.
*
* If @value is empty and a matching xattr object is found we delete it if
* XATTR_REPLACE is specified in @flags or @flags is zero.
*
* If @value is empty and no matching xattr object for @name is found we do
* nothing if XATTR_CREATE is specified in @flags or @flags is zero. For
* XATTR_REPLACE we fail as mentioned above.
*
* Return: On success, the removed or replaced xattr is returned, to be freed
* by the caller; or NULL if none. On failure a negative error code is returned.
*/
struct simple_xattr *simple_xattr_set(struct simple_xattrs *xattrs,
const char *name, const void *value,
size_t size, int flags)
{
struct simple_xattr *old_xattr = NULL, *new_xattr = NULL;
struct rb_node *parent = NULL, **rbp;
int err = 0, ret;
/* value == NULL means remove */
if (value) {
new_xattr = simple_xattr_alloc(value, size);
if (!new_xattr)
return ERR_PTR(-ENOMEM);
new_xattr->name = kstrdup(name, GFP_KERNEL_ACCOUNT);
if (!new_xattr->name) {
simple_xattr_free(new_xattr);
return ERR_PTR(-ENOMEM);
}
}
write_lock(&xattrs->lock);
rbp = &xattrs->rb_root.rb_node;
while (*rbp) {
parent = *rbp;
ret = rbtree_simple_xattr_cmp(name, *rbp);
if (ret < 0)
rbp = &(*rbp)->rb_left;
else if (ret > 0)
rbp = &(*rbp)->rb_right;
else
old_xattr = rb_entry(*rbp, struct simple_xattr, rb_node);
if (old_xattr)
break;
}
if (old_xattr) {
/* Fail if XATTR_CREATE is requested and the xattr exists. */
if (flags & XATTR_CREATE) {
err = -EEXIST;
goto out_unlock;
}
if (new_xattr)
rb_replace_node(&old_xattr->rb_node,
&new_xattr->rb_node, &xattrs->rb_root);
else
rb_erase(&old_xattr->rb_node, &xattrs->rb_root);
} else {
/* Fail if XATTR_REPLACE is requested but no xattr is found. */
if (flags & XATTR_REPLACE) {
err = -ENODATA;
goto out_unlock;
}
/*
* If XATTR_CREATE or no flags are specified together with a
* new value simply insert it.
*/
if (new_xattr) {
rb_link_node(&new_xattr->rb_node, parent, rbp);
rb_insert_color(&new_xattr->rb_node, &xattrs->rb_root);
}
/*
* If XATTR_CREATE or no flags are specified and neither an
* old or new xattr exist then we don't need to do anything.
*/
}
out_unlock:
write_unlock(&xattrs->lock);
if (!err)
return old_xattr;
simple_xattr_free(new_xattr);
return ERR_PTR(err);
}
static bool xattr_is_trusted(const char *name)
{
return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
}
/**
* simple_xattr_list - list all xattr objects
* @inode: inode from which to get the xattrs
* @xattrs: the header of the xattr object
* @buffer: the buffer to store all xattrs into
* @size: the size of @buffer
*
* List all xattrs associated with @inode. If @buffer is NULL we returned
* the required size of the buffer. If @buffer is provided we store the
* xattrs value into it provided it is big enough.
*
* Note, the number of xattr names that can be listed with listxattr(2) is
* limited to XATTR_LIST_MAX aka 65536 bytes. If a larger buffer is passed
* then vfs_listxattr() caps it to XATTR_LIST_MAX and if more xattr names
* are found it will return -E2BIG.
*
* Return: On success the required size or the size of the copied xattrs is
* returned. On error a negative error code is returned.
*/
ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
char *buffer, size_t size)
{
bool trusted = ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN);
struct simple_xattr *xattr;
struct rb_node *rbp;
ssize_t remaining_size = size;
int err = 0;
err = posix_acl_listxattr(inode, &buffer, &remaining_size);
if (err)
return err;
read_lock(&xattrs->lock);
for (rbp = rb_first(&xattrs->rb_root); rbp; rbp = rb_next(rbp)) {
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
/* skip "trusted." attributes for unprivileged callers */
if (!trusted && xattr_is_trusted(xattr->name))
continue;
err = xattr_list_one(&buffer, &remaining_size, xattr->name);
if (err)
break;
}
read_unlock(&xattrs->lock);
return err ? err : size - remaining_size;
}
/**
* rbtree_simple_xattr_less - compare two xattr rbtree nodes
* @new_node: new node
* @node: current node
*
* Compare the xattr attached to @new_node with the xattr attached to @node.
* Note that this function technically tolerates duplicate entries.
*
* Return: True if insertion point in the rbtree is found.
*/
static bool rbtree_simple_xattr_less(struct rb_node *new_node,
const struct rb_node *node)
{
return rbtree_simple_xattr_node_cmp(new_node, node) < 0;
}
/**
* simple_xattr_add - add xattr objects
* @xattrs: the header of the xattr object
* @new_xattr: the xattr object to add
*
* Add an xattr object to @xattrs. This assumes no replacement or removal
* of matching xattrs is wanted. Should only be called during inode
* initialization when a few distinct initial xattrs are supposed to be set.
*/
void simple_xattr_add(struct simple_xattrs *xattrs,
struct simple_xattr *new_xattr)
{
write_lock(&xattrs->lock);
rb_add(&new_xattr->rb_node, &xattrs->rb_root, rbtree_simple_xattr_less);
write_unlock(&xattrs->lock);
}
/**
* simple_xattrs_init - initialize new xattr header
* @xattrs: header to initialize
*
* Initialize relevant fields of a an xattr header.
*/
void simple_xattrs_init(struct simple_xattrs *xattrs)
{
xattrs->rb_root = RB_ROOT;
rwlock_init(&xattrs->lock);
}
/**
* simple_xattrs_free - free xattrs
* @xattrs: xattr header whose xattrs to destroy
* @freed_space: approximate number of bytes of memory freed from @xattrs
*
* Destroy all xattrs in @xattr. When this is called no one can hold a
* reference to any of the xattrs anymore.
*/
void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space)
{
struct rb_node *rbp;
if (freed_space)
*freed_space = 0;
rbp = rb_first(&xattrs->rb_root);
while (rbp) {
struct simple_xattr *xattr;
struct rb_node *rbp_next;
rbp_next = rb_next(rbp);
xattr = rb_entry(rbp, struct simple_xattr, rb_node);
rb_erase(&xattr->rb_node, &xattrs->rb_root);
if (freed_space)
*freed_space += simple_xattr_space(xattr->name,
xattr->size);
simple_xattr_free(xattr);
rbp = rbp_next;
}
}
| linux-master | fs/xattr.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/pipe.c
*
* Copyright (C) 1991, 1992, 1999 Linus Torvalds
*/
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/log2.h>
#include <linux/mount.h>
#include <linux/pseudo_fs.h>
#include <linux/magic.h>
#include <linux/pipe_fs_i.h>
#include <linux/uio.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/audit.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <linux/memcontrol.h>
#include <linux/watch_queue.h>
#include <linux/sysctl.h>
#include <linux/uaccess.h>
#include <asm/ioctls.h>
#include "internal.h"
/*
* New pipe buffers will be restricted to this size while the user is exceeding
* their pipe buffer quota. The general pipe use case needs at least two
* buffers: one for data yet to be read, and one for new data. If this is less
* than two, then a write to a non-empty pipe may block even if the pipe is not
* full. This can occur with GNU make jobserver or similar uses of pipes as
* semaphores: multiple processes may be waiting to write tokens back to the
* pipe before reading tokens: https://lore.kernel.org/lkml/1628086770.5rn8p04n6j.none@localhost/.
*
* Users can reduce their pipe buffers with F_SETPIPE_SZ below this at their
* own risk, namely: pipe writes to non-full pipes may block until the pipe is
* emptied.
*/
#define PIPE_MIN_DEF_BUFFERS 2
/*
* The max size that a non-root user is allowed to grow the pipe. Can
* be set by root in /proc/sys/fs/pipe-max-size
*/
static unsigned int pipe_max_size = 1048576;
/* Maximum allocatable pages per user. Hard limit is unset by default, soft
* matches default values.
*/
static unsigned long pipe_user_pages_hard;
static unsigned long pipe_user_pages_soft = PIPE_DEF_BUFFERS * INR_OPEN_CUR;
/*
* We use head and tail indices that aren't masked off, except at the point of
* dereference, but rather they're allowed to wrap naturally. This means there
* isn't a dead spot in the buffer, but the ring has to be a power of two and
* <= 2^31.
* -- David Howells 2019-09-23.
*
* Reads with count = 0 should always return 0.
* -- Julian Bradfield 1999-06-07.
*
* FIFOs and Pipes now generate SIGIO for both readers and writers.
* -- Jeremy Elson <[email protected]> 2001-08-16
*
* pipe_read & write cleanup
* -- Manfred Spraul <[email protected]> 2002-05-09
*/
static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass)
{
if (pipe->files)
mutex_lock_nested(&pipe->mutex, subclass);
}
void pipe_lock(struct pipe_inode_info *pipe)
{
/*
* pipe_lock() nests non-pipe inode locks (for writing to a file)
*/
pipe_lock_nested(pipe, I_MUTEX_PARENT);
}
EXPORT_SYMBOL(pipe_lock);
void pipe_unlock(struct pipe_inode_info *pipe)
{
if (pipe->files)
mutex_unlock(&pipe->mutex);
}
EXPORT_SYMBOL(pipe_unlock);
static inline void __pipe_lock(struct pipe_inode_info *pipe)
{
mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT);
}
static inline void __pipe_unlock(struct pipe_inode_info *pipe)
{
mutex_unlock(&pipe->mutex);
}
void pipe_double_lock(struct pipe_inode_info *pipe1,
struct pipe_inode_info *pipe2)
{
BUG_ON(pipe1 == pipe2);
if (pipe1 < pipe2) {
pipe_lock_nested(pipe1, I_MUTEX_PARENT);
pipe_lock_nested(pipe2, I_MUTEX_CHILD);
} else {
pipe_lock_nested(pipe2, I_MUTEX_PARENT);
pipe_lock_nested(pipe1, I_MUTEX_CHILD);
}
}
static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct page *page = buf->page;
/*
* If nobody else uses this page, and we don't already have a
* temporary page, let's keep track of it as a one-deep
* allocation cache. (Otherwise just release our reference to it)
*/
if (page_count(page) == 1 && !pipe->tmp_page)
pipe->tmp_page = page;
else
put_page(page);
}
static bool anon_pipe_buf_try_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct page *page = buf->page;
if (page_count(page) != 1)
return false;
memcg_kmem_uncharge_page(page, 0);
__SetPageLocked(page);
return true;
}
/**
* generic_pipe_buf_try_steal - attempt to take ownership of a &pipe_buffer
* @pipe: the pipe that the buffer belongs to
* @buf: the buffer to attempt to steal
*
* Description:
* This function attempts to steal the &struct page attached to
* @buf. If successful, this function returns 0 and returns with
* the page locked. The caller may then reuse the page for whatever
* he wishes; the typical use is insertion into a different file
* page cache.
*/
bool generic_pipe_buf_try_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct page *page = buf->page;
/*
* A reference of one is golden, that means that the owner of this
* page is the only one holding a reference to it. lock the page
* and return OK.
*/
if (page_count(page) == 1) {
lock_page(page);
return true;
}
return false;
}
EXPORT_SYMBOL(generic_pipe_buf_try_steal);
/**
* generic_pipe_buf_get - get a reference to a &struct pipe_buffer
* @pipe: the pipe that the buffer belongs to
* @buf: the buffer to get a reference to
*
* Description:
* This function grabs an extra reference to @buf. It's used in
* the tee() system call, when we duplicate the buffers in one
* pipe into another.
*/
bool generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
{
return try_get_page(buf->page);
}
EXPORT_SYMBOL(generic_pipe_buf_get);
/**
* generic_pipe_buf_release - put a reference to a &struct pipe_buffer
* @pipe: the pipe that the buffer belongs to
* @buf: the buffer to put a reference to
*
* Description:
* This function releases a reference to @buf.
*/
void generic_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
put_page(buf->page);
}
EXPORT_SYMBOL(generic_pipe_buf_release);
static const struct pipe_buf_operations anon_pipe_buf_ops = {
.release = anon_pipe_buf_release,
.try_steal = anon_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */
static inline bool pipe_readable(const struct pipe_inode_info *pipe)
{
unsigned int head = READ_ONCE(pipe->head);
unsigned int tail = READ_ONCE(pipe->tail);
unsigned int writers = READ_ONCE(pipe->writers);
return !pipe_empty(head, tail) || !writers;
}
static ssize_t
pipe_read(struct kiocb *iocb, struct iov_iter *to)
{
size_t total_len = iov_iter_count(to);
struct file *filp = iocb->ki_filp;
struct pipe_inode_info *pipe = filp->private_data;
bool was_full, wake_next_reader = false;
ssize_t ret;
/* Null read succeeds. */
if (unlikely(total_len == 0))
return 0;
ret = 0;
__pipe_lock(pipe);
/*
* We only wake up writers if the pipe was full when we started
* reading in order to avoid unnecessary wakeups.
*
* But when we do wake up writers, we do so using a sync wakeup
* (WF_SYNC), because we want them to get going and generate more
* data for us.
*/
was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage);
for (;;) {
/* Read ->head with a barrier vs post_one_notification() */
unsigned int head = smp_load_acquire(&pipe->head);
unsigned int tail = pipe->tail;
unsigned int mask = pipe->ring_size - 1;
#ifdef CONFIG_WATCH_QUEUE
if (pipe->note_loss) {
struct watch_notification n;
if (total_len < 8) {
if (ret == 0)
ret = -ENOBUFS;
break;
}
n.type = WATCH_TYPE_META;
n.subtype = WATCH_META_LOSS_NOTIFICATION;
n.info = watch_sizeof(n);
if (copy_to_iter(&n, sizeof(n), to) != sizeof(n)) {
if (ret == 0)
ret = -EFAULT;
break;
}
ret += sizeof(n);
total_len -= sizeof(n);
pipe->note_loss = false;
}
#endif
if (!pipe_empty(head, tail)) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
size_t chars = buf->len;
size_t written;
int error;
if (chars > total_len) {
if (buf->flags & PIPE_BUF_FLAG_WHOLE) {
if (ret == 0)
ret = -ENOBUFS;
break;
}
chars = total_len;
}
error = pipe_buf_confirm(pipe, buf);
if (error) {
if (!ret)
ret = error;
break;
}
written = copy_page_to_iter(buf->page, buf->offset, chars, to);
if (unlikely(written < chars)) {
if (!ret)
ret = -EFAULT;
break;
}
ret += chars;
buf->offset += chars;
buf->len -= chars;
/* Was it a packet buffer? Clean up and exit */
if (buf->flags & PIPE_BUF_FLAG_PACKET) {
total_len = chars;
buf->len = 0;
}
if (!buf->len) {
pipe_buf_release(pipe, buf);
spin_lock_irq(&pipe->rd_wait.lock);
#ifdef CONFIG_WATCH_QUEUE
if (buf->flags & PIPE_BUF_FLAG_LOSS)
pipe->note_loss = true;
#endif
tail++;
pipe->tail = tail;
spin_unlock_irq(&pipe->rd_wait.lock);
}
total_len -= chars;
if (!total_len)
break; /* common path: read succeeded */
if (!pipe_empty(head, tail)) /* More to do? */
continue;
}
if (!pipe->writers)
break;
if (ret)
break;
if ((filp->f_flags & O_NONBLOCK) ||
(iocb->ki_flags & IOCB_NOWAIT)) {
ret = -EAGAIN;
break;
}
__pipe_unlock(pipe);
/*
* We only get here if we didn't actually read anything.
*
* However, we could have seen (and removed) a zero-sized
* pipe buffer, and might have made space in the buffers
* that way.
*
* You can't make zero-sized pipe buffers by doing an empty
* write (not even in packet mode), but they can happen if
* the writer gets an EFAULT when trying to fill a buffer
* that already got allocated and inserted in the buffer
* array.
*
* So we still need to wake up any pending writers in the
* _very_ unlikely case that the pipe was full, but we got
* no data.
*/
if (unlikely(was_full))
wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
/*
* But because we didn't read anything, at this point we can
* just return directly with -ERESTARTSYS if we're interrupted,
* since we've done any required wakeups and there's no need
* to mark anything accessed. And we've dropped the lock.
*/
if (wait_event_interruptible_exclusive(pipe->rd_wait, pipe_readable(pipe)) < 0)
return -ERESTARTSYS;
__pipe_lock(pipe);
was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage);
wake_next_reader = true;
}
if (pipe_empty(pipe->head, pipe->tail))
wake_next_reader = false;
__pipe_unlock(pipe);
if (was_full)
wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
if (wake_next_reader)
wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
if (ret > 0)
file_accessed(filp);
return ret;
}
static inline int is_packetized(struct file *file)
{
return (file->f_flags & O_DIRECT) != 0;
}
/* Done while waiting without holding the pipe lock - thus the READ_ONCE() */
static inline bool pipe_writable(const struct pipe_inode_info *pipe)
{
unsigned int head = READ_ONCE(pipe->head);
unsigned int tail = READ_ONCE(pipe->tail);
unsigned int max_usage = READ_ONCE(pipe->max_usage);
return !pipe_full(head, tail, max_usage) ||
!READ_ONCE(pipe->readers);
}
static ssize_t
pipe_write(struct kiocb *iocb, struct iov_iter *from)
{
struct file *filp = iocb->ki_filp;
struct pipe_inode_info *pipe = filp->private_data;
unsigned int head;
ssize_t ret = 0;
size_t total_len = iov_iter_count(from);
ssize_t chars;
bool was_empty = false;
bool wake_next_writer = false;
/* Null write succeeds. */
if (unlikely(total_len == 0))
return 0;
__pipe_lock(pipe);
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
goto out;
}
#ifdef CONFIG_WATCH_QUEUE
if (pipe->watch_queue) {
ret = -EXDEV;
goto out;
}
#endif
/*
* If it wasn't empty we try to merge new data into
* the last buffer.
*
* That naturally merges small writes, but it also
* page-aligns the rest of the writes for large writes
* spanning multiple pages.
*/
head = pipe->head;
was_empty = pipe_empty(head, pipe->tail);
chars = total_len & (PAGE_SIZE-1);
if (chars && !was_empty) {
unsigned int mask = pipe->ring_size - 1;
struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask];
int offset = buf->offset + buf->len;
if ((buf->flags & PIPE_BUF_FLAG_CAN_MERGE) &&
offset + chars <= PAGE_SIZE) {
ret = pipe_buf_confirm(pipe, buf);
if (ret)
goto out;
ret = copy_page_from_iter(buf->page, offset, chars, from);
if (unlikely(ret < chars)) {
ret = -EFAULT;
goto out;
}
buf->len += ret;
if (!iov_iter_count(from))
goto out;
}
}
for (;;) {
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
if (!ret)
ret = -EPIPE;
break;
}
head = pipe->head;
if (!pipe_full(head, pipe->tail, pipe->max_usage)) {
unsigned int mask = pipe->ring_size - 1;
struct pipe_buffer *buf;
struct page *page = pipe->tmp_page;
int copied;
if (!page) {
page = alloc_page(GFP_HIGHUSER | __GFP_ACCOUNT);
if (unlikely(!page)) {
ret = ret ? : -ENOMEM;
break;
}
pipe->tmp_page = page;
}
/* Allocate a slot in the ring in advance and attach an
* empty buffer. If we fault or otherwise fail to use
* it, either the reader will consume it or it'll still
* be there for the next write.
*/
spin_lock_irq(&pipe->rd_wait.lock);
head = pipe->head;
if (pipe_full(head, pipe->tail, pipe->max_usage)) {
spin_unlock_irq(&pipe->rd_wait.lock);
continue;
}
pipe->head = head + 1;
spin_unlock_irq(&pipe->rd_wait.lock);
/* Insert it into the buffer array */
buf = &pipe->bufs[head & mask];
buf->page = page;
buf->ops = &anon_pipe_buf_ops;
buf->offset = 0;
buf->len = 0;
if (is_packetized(filp))
buf->flags = PIPE_BUF_FLAG_PACKET;
else
buf->flags = PIPE_BUF_FLAG_CAN_MERGE;
pipe->tmp_page = NULL;
copied = copy_page_from_iter(page, 0, PAGE_SIZE, from);
if (unlikely(copied < PAGE_SIZE && iov_iter_count(from))) {
if (!ret)
ret = -EFAULT;
break;
}
ret += copied;
buf->offset = 0;
buf->len = copied;
if (!iov_iter_count(from))
break;
}
if (!pipe_full(head, pipe->tail, pipe->max_usage))
continue;
/* Wait for buffer space to become available. */
if ((filp->f_flags & O_NONBLOCK) ||
(iocb->ki_flags & IOCB_NOWAIT)) {
if (!ret)
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
if (!ret)
ret = -ERESTARTSYS;
break;
}
/*
* We're going to release the pipe lock and wait for more
* space. We wake up any readers if necessary, and then
* after waiting we need to re-check whether the pipe
* become empty while we dropped the lock.
*/
__pipe_unlock(pipe);
if (was_empty)
wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe));
__pipe_lock(pipe);
was_empty = pipe_empty(pipe->head, pipe->tail);
wake_next_writer = true;
}
out:
if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))
wake_next_writer = false;
__pipe_unlock(pipe);
/*
* If we do do a wakeup event, we do a 'sync' wakeup, because we
* want the reader to start processing things asap, rather than
* leave the data pending.
*
* This is particularly important for small writes, because of
* how (for example) the GNU make jobserver uses small writes to
* wake up pending jobs
*
* Epoll nonsensically wants a wakeup whether the pipe
* was already empty or not.
*/
if (was_empty || pipe->poll_usage)
wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
if (wake_next_writer)
wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) {
int err = file_update_time(filp);
if (err)
ret = err;
sb_end_write(file_inode(filp)->i_sb);
}
return ret;
}
static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct pipe_inode_info *pipe = filp->private_data;
unsigned int count, head, tail, mask;
switch (cmd) {
case FIONREAD:
__pipe_lock(pipe);
count = 0;
head = pipe->head;
tail = pipe->tail;
mask = pipe->ring_size - 1;
while (tail != head) {
count += pipe->bufs[tail & mask].len;
tail++;
}
__pipe_unlock(pipe);
return put_user(count, (int __user *)arg);
#ifdef CONFIG_WATCH_QUEUE
case IOC_WATCH_QUEUE_SET_SIZE: {
int ret;
__pipe_lock(pipe);
ret = watch_queue_set_size(pipe, arg);
__pipe_unlock(pipe);
return ret;
}
case IOC_WATCH_QUEUE_SET_FILTER:
return watch_queue_set_filter(
pipe, (struct watch_notification_filter __user *)arg);
#endif
default:
return -ENOIOCTLCMD;
}
}
/* No kernel lock held - fine */
static __poll_t
pipe_poll(struct file *filp, poll_table *wait)
{
__poll_t mask;
struct pipe_inode_info *pipe = filp->private_data;
unsigned int head, tail;
/* Epoll has some historical nasty semantics, this enables them */
WRITE_ONCE(pipe->poll_usage, true);
/*
* Reading pipe state only -- no need for acquiring the semaphore.
*
* But because this is racy, the code has to add the
* entry to the poll table _first_ ..
*/
if (filp->f_mode & FMODE_READ)
poll_wait(filp, &pipe->rd_wait, wait);
if (filp->f_mode & FMODE_WRITE)
poll_wait(filp, &pipe->wr_wait, wait);
/*
* .. and only then can you do the racy tests. That way,
* if something changes and you got it wrong, the poll
* table entry will wake you up and fix it.
*/
head = READ_ONCE(pipe->head);
tail = READ_ONCE(pipe->tail);
mask = 0;
if (filp->f_mode & FMODE_READ) {
if (!pipe_empty(head, tail))
mask |= EPOLLIN | EPOLLRDNORM;
if (!pipe->writers && filp->f_version != pipe->w_counter)
mask |= EPOLLHUP;
}
if (filp->f_mode & FMODE_WRITE) {
if (!pipe_full(head, tail, pipe->max_usage))
mask |= EPOLLOUT | EPOLLWRNORM;
/*
* Most Unices do not set EPOLLERR for FIFOs but on Linux they
* behave exactly like pipes for poll().
*/
if (!pipe->readers)
mask |= EPOLLERR;
}
return mask;
}
static void put_pipe_info(struct inode *inode, struct pipe_inode_info *pipe)
{
int kill = 0;
spin_lock(&inode->i_lock);
if (!--pipe->files) {
inode->i_pipe = NULL;
kill = 1;
}
spin_unlock(&inode->i_lock);
if (kill)
free_pipe_info(pipe);
}
static int
pipe_release(struct inode *inode, struct file *file)
{
struct pipe_inode_info *pipe = file->private_data;
__pipe_lock(pipe);
if (file->f_mode & FMODE_READ)
pipe->readers--;
if (file->f_mode & FMODE_WRITE)
pipe->writers--;
/* Was that the last reader or writer, but not the other side? */
if (!pipe->readers != !pipe->writers) {
wake_up_interruptible_all(&pipe->rd_wait);
wake_up_interruptible_all(&pipe->wr_wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
}
__pipe_unlock(pipe);
put_pipe_info(inode, pipe);
return 0;
}
static int
pipe_fasync(int fd, struct file *filp, int on)
{
struct pipe_inode_info *pipe = filp->private_data;
int retval = 0;
__pipe_lock(pipe);
if (filp->f_mode & FMODE_READ)
retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
if ((filp->f_mode & FMODE_WRITE) && retval >= 0) {
retval = fasync_helper(fd, filp, on, &pipe->fasync_writers);
if (retval < 0 && (filp->f_mode & FMODE_READ))
/* this can happen only if on == T */
fasync_helper(-1, filp, 0, &pipe->fasync_readers);
}
__pipe_unlock(pipe);
return retval;
}
unsigned long account_pipe_buffers(struct user_struct *user,
unsigned long old, unsigned long new)
{
return atomic_long_add_return(new - old, &user->pipe_bufs);
}
bool too_many_pipe_buffers_soft(unsigned long user_bufs)
{
unsigned long soft_limit = READ_ONCE(pipe_user_pages_soft);
return soft_limit && user_bufs > soft_limit;
}
bool too_many_pipe_buffers_hard(unsigned long user_bufs)
{
unsigned long hard_limit = READ_ONCE(pipe_user_pages_hard);
return hard_limit && user_bufs > hard_limit;
}
bool pipe_is_unprivileged_user(void)
{
return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
}
struct pipe_inode_info *alloc_pipe_info(void)
{
struct pipe_inode_info *pipe;
unsigned long pipe_bufs = PIPE_DEF_BUFFERS;
struct user_struct *user = get_current_user();
unsigned long user_bufs;
unsigned int max_size = READ_ONCE(pipe_max_size);
pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL_ACCOUNT);
if (pipe == NULL)
goto out_free_uid;
if (pipe_bufs * PAGE_SIZE > max_size && !capable(CAP_SYS_RESOURCE))
pipe_bufs = max_size >> PAGE_SHIFT;
user_bufs = account_pipe_buffers(user, 0, pipe_bufs);
if (too_many_pipe_buffers_soft(user_bufs) && pipe_is_unprivileged_user()) {
user_bufs = account_pipe_buffers(user, pipe_bufs, PIPE_MIN_DEF_BUFFERS);
pipe_bufs = PIPE_MIN_DEF_BUFFERS;
}
if (too_many_pipe_buffers_hard(user_bufs) && pipe_is_unprivileged_user())
goto out_revert_acct;
pipe->bufs = kcalloc(pipe_bufs, sizeof(struct pipe_buffer),
GFP_KERNEL_ACCOUNT);
if (pipe->bufs) {
init_waitqueue_head(&pipe->rd_wait);
init_waitqueue_head(&pipe->wr_wait);
pipe->r_counter = pipe->w_counter = 1;
pipe->max_usage = pipe_bufs;
pipe->ring_size = pipe_bufs;
pipe->nr_accounted = pipe_bufs;
pipe->user = user;
mutex_init(&pipe->mutex);
return pipe;
}
out_revert_acct:
(void) account_pipe_buffers(user, pipe_bufs, 0);
kfree(pipe);
out_free_uid:
free_uid(user);
return NULL;
}
void free_pipe_info(struct pipe_inode_info *pipe)
{
unsigned int i;
#ifdef CONFIG_WATCH_QUEUE
if (pipe->watch_queue)
watch_queue_clear(pipe->watch_queue);
#endif
(void) account_pipe_buffers(pipe->user, pipe->nr_accounted, 0);
free_uid(pipe->user);
for (i = 0; i < pipe->ring_size; i++) {
struct pipe_buffer *buf = pipe->bufs + i;
if (buf->ops)
pipe_buf_release(pipe, buf);
}
#ifdef CONFIG_WATCH_QUEUE
if (pipe->watch_queue)
put_watch_queue(pipe->watch_queue);
#endif
if (pipe->tmp_page)
__free_page(pipe->tmp_page);
kfree(pipe->bufs);
kfree(pipe);
}
static struct vfsmount *pipe_mnt __read_mostly;
/*
* pipefs_dname() is called from d_path().
*/
static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen)
{
return dynamic_dname(buffer, buflen, "pipe:[%lu]",
d_inode(dentry)->i_ino);
}
static const struct dentry_operations pipefs_dentry_operations = {
.d_dname = pipefs_dname,
};
static struct inode * get_pipe_inode(void)
{
struct inode *inode = new_inode_pseudo(pipe_mnt->mnt_sb);
struct pipe_inode_info *pipe;
if (!inode)
goto fail_inode;
inode->i_ino = get_next_ino();
pipe = alloc_pipe_info();
if (!pipe)
goto fail_iput;
inode->i_pipe = pipe;
pipe->files = 2;
pipe->readers = pipe->writers = 1;
inode->i_fop = &pipefifo_fops;
/*
* Mark the inode dirty from the very beginning,
* that way it will never be moved to the dirty
* list because "mark_inode_dirty()" will think
* that it already _is_ on the dirty list.
*/
inode->i_state = I_DIRTY;
inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
return inode;
fail_iput:
iput(inode);
fail_inode:
return NULL;
}
int create_pipe_files(struct file **res, int flags)
{
struct inode *inode = get_pipe_inode();
struct file *f;
int error;
if (!inode)
return -ENFILE;
if (flags & O_NOTIFICATION_PIPE) {
error = watch_queue_init(inode->i_pipe);
if (error) {
free_pipe_info(inode->i_pipe);
iput(inode);
return error;
}
}
f = alloc_file_pseudo(inode, pipe_mnt, "",
O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT)),
&pipefifo_fops);
if (IS_ERR(f)) {
free_pipe_info(inode->i_pipe);
iput(inode);
return PTR_ERR(f);
}
f->private_data = inode->i_pipe;
res[0] = alloc_file_clone(f, O_RDONLY | (flags & O_NONBLOCK),
&pipefifo_fops);
if (IS_ERR(res[0])) {
put_pipe_info(inode, inode->i_pipe);
fput(f);
return PTR_ERR(res[0]);
}
res[0]->private_data = inode->i_pipe;
res[1] = f;
stream_open(inode, res[0]);
stream_open(inode, res[1]);
return 0;
}
static int __do_pipe_flags(int *fd, struct file **files, int flags)
{
int error;
int fdw, fdr;
if (flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT | O_NOTIFICATION_PIPE))
return -EINVAL;
error = create_pipe_files(files, flags);
if (error)
return error;
error = get_unused_fd_flags(flags);
if (error < 0)
goto err_read_pipe;
fdr = error;
error = get_unused_fd_flags(flags);
if (error < 0)
goto err_fdr;
fdw = error;
audit_fd_pair(fdr, fdw);
fd[0] = fdr;
fd[1] = fdw;
/* pipe groks IOCB_NOWAIT */
files[0]->f_mode |= FMODE_NOWAIT;
files[1]->f_mode |= FMODE_NOWAIT;
return 0;
err_fdr:
put_unused_fd(fdr);
err_read_pipe:
fput(files[0]);
fput(files[1]);
return error;
}
int do_pipe_flags(int *fd, int flags)
{
struct file *files[2];
int error = __do_pipe_flags(fd, files, flags);
if (!error) {
fd_install(fd[0], files[0]);
fd_install(fd[1], files[1]);
}
return error;
}
/*
* sys_pipe() is the normal C calling standard for creating
* a pipe. It's not the way Unix traditionally does this, though.
*/
static int do_pipe2(int __user *fildes, int flags)
{
struct file *files[2];
int fd[2];
int error;
error = __do_pipe_flags(fd, files, flags);
if (!error) {
if (unlikely(copy_to_user(fildes, fd, sizeof(fd)))) {
fput(files[0]);
fput(files[1]);
put_unused_fd(fd[0]);
put_unused_fd(fd[1]);
error = -EFAULT;
} else {
fd_install(fd[0], files[0]);
fd_install(fd[1], files[1]);
}
}
return error;
}
SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags)
{
return do_pipe2(fildes, flags);
}
SYSCALL_DEFINE1(pipe, int __user *, fildes)
{
return do_pipe2(fildes, 0);
}
/*
* This is the stupid "wait for pipe to be readable or writable"
* model.
*
* See pipe_read/write() for the proper kind of exclusive wait,
* but that requires that we wake up any other readers/writers
* if we then do not end up reading everything (ie the whole
* "wake_next_reader/writer" logic in pipe_read/write()).
*/
void pipe_wait_readable(struct pipe_inode_info *pipe)
{
pipe_unlock(pipe);
wait_event_interruptible(pipe->rd_wait, pipe_readable(pipe));
pipe_lock(pipe);
}
void pipe_wait_writable(struct pipe_inode_info *pipe)
{
pipe_unlock(pipe);
wait_event_interruptible(pipe->wr_wait, pipe_writable(pipe));
pipe_lock(pipe);
}
/*
* This depends on both the wait (here) and the wakeup (wake_up_partner)
* holding the pipe lock, so "*cnt" is stable and we know a wakeup cannot
* race with the count check and waitqueue prep.
*
* Normally in order to avoid races, you'd do the prepare_to_wait() first,
* then check the condition you're waiting for, and only then sleep. But
* because of the pipe lock, we can check the condition before being on
* the wait queue.
*
* We use the 'rd_wait' waitqueue for pipe partner waiting.
*/
static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt)
{
DEFINE_WAIT(rdwait);
int cur = *cnt;
while (cur == *cnt) {
prepare_to_wait(&pipe->rd_wait, &rdwait, TASK_INTERRUPTIBLE);
pipe_unlock(pipe);
schedule();
finish_wait(&pipe->rd_wait, &rdwait);
pipe_lock(pipe);
if (signal_pending(current))
break;
}
return cur == *cnt ? -ERESTARTSYS : 0;
}
static void wake_up_partner(struct pipe_inode_info *pipe)
{
wake_up_interruptible_all(&pipe->rd_wait);
}
static int fifo_open(struct inode *inode, struct file *filp)
{
struct pipe_inode_info *pipe;
bool is_pipe = inode->i_sb->s_magic == PIPEFS_MAGIC;
int ret;
filp->f_version = 0;
spin_lock(&inode->i_lock);
if (inode->i_pipe) {
pipe = inode->i_pipe;
pipe->files++;
spin_unlock(&inode->i_lock);
} else {
spin_unlock(&inode->i_lock);
pipe = alloc_pipe_info();
if (!pipe)
return -ENOMEM;
pipe->files = 1;
spin_lock(&inode->i_lock);
if (unlikely(inode->i_pipe)) {
inode->i_pipe->files++;
spin_unlock(&inode->i_lock);
free_pipe_info(pipe);
pipe = inode->i_pipe;
} else {
inode->i_pipe = pipe;
spin_unlock(&inode->i_lock);
}
}
filp->private_data = pipe;
/* OK, we have a pipe and it's pinned down */
__pipe_lock(pipe);
/* We can only do regular read/write on fifos */
stream_open(inode, filp);
switch (filp->f_mode & (FMODE_READ | FMODE_WRITE)) {
case FMODE_READ:
/*
* O_RDONLY
* POSIX.1 says that O_NONBLOCK means return with the FIFO
* opened, even when there is no process writing the FIFO.
*/
pipe->r_counter++;
if (pipe->readers++ == 0)
wake_up_partner(pipe);
if (!is_pipe && !pipe->writers) {
if ((filp->f_flags & O_NONBLOCK)) {
/* suppress EPOLLHUP until we have
* seen a writer */
filp->f_version = pipe->w_counter;
} else {
if (wait_for_partner(pipe, &pipe->w_counter))
goto err_rd;
}
}
break;
case FMODE_WRITE:
/*
* O_WRONLY
* POSIX.1 says that O_NONBLOCK means return -1 with
* errno=ENXIO when there is no process reading the FIFO.
*/
ret = -ENXIO;
if (!is_pipe && (filp->f_flags & O_NONBLOCK) && !pipe->readers)
goto err;
pipe->w_counter++;
if (!pipe->writers++)
wake_up_partner(pipe);
if (!is_pipe && !pipe->readers) {
if (wait_for_partner(pipe, &pipe->r_counter))
goto err_wr;
}
break;
case FMODE_READ | FMODE_WRITE:
/*
* O_RDWR
* POSIX.1 leaves this case "undefined" when O_NONBLOCK is set.
* This implementation will NEVER block on a O_RDWR open, since
* the process can at least talk to itself.
*/
pipe->readers++;
pipe->writers++;
pipe->r_counter++;
pipe->w_counter++;
if (pipe->readers == 1 || pipe->writers == 1)
wake_up_partner(pipe);
break;
default:
ret = -EINVAL;
goto err;
}
/* Ok! */
__pipe_unlock(pipe);
return 0;
err_rd:
if (!--pipe->readers)
wake_up_interruptible(&pipe->wr_wait);
ret = -ERESTARTSYS;
goto err;
err_wr:
if (!--pipe->writers)
wake_up_interruptible_all(&pipe->rd_wait);
ret = -ERESTARTSYS;
goto err;
err:
__pipe_unlock(pipe);
put_pipe_info(inode, pipe);
return ret;
}
const struct file_operations pipefifo_fops = {
.open = fifo_open,
.llseek = no_llseek,
.read_iter = pipe_read,
.write_iter = pipe_write,
.poll = pipe_poll,
.unlocked_ioctl = pipe_ioctl,
.release = pipe_release,
.fasync = pipe_fasync,
.splice_write = iter_file_splice_write,
};
/*
* Currently we rely on the pipe array holding a power-of-2 number
* of pages. Returns 0 on error.
*/
unsigned int round_pipe_size(unsigned int size)
{
if (size > (1U << 31))
return 0;
/* Minimum pipe size, as required by POSIX */
if (size < PAGE_SIZE)
return PAGE_SIZE;
return roundup_pow_of_two(size);
}
/*
* Resize the pipe ring to a number of slots.
*
* Note the pipe can be reduced in capacity, but only if the current
* occupancy doesn't exceed nr_slots; if it does, EBUSY will be
* returned instead.
*/
int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots)
{
struct pipe_buffer *bufs;
unsigned int head, tail, mask, n;
bufs = kcalloc(nr_slots, sizeof(*bufs),
GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
if (unlikely(!bufs))
return -ENOMEM;
spin_lock_irq(&pipe->rd_wait.lock);
mask = pipe->ring_size - 1;
head = pipe->head;
tail = pipe->tail;
n = pipe_occupancy(head, tail);
if (nr_slots < n) {
spin_unlock_irq(&pipe->rd_wait.lock);
kfree(bufs);
return -EBUSY;
}
/*
* The pipe array wraps around, so just start the new one at zero
* and adjust the indices.
*/
if (n > 0) {
unsigned int h = head & mask;
unsigned int t = tail & mask;
if (h > t) {
memcpy(bufs, pipe->bufs + t,
n * sizeof(struct pipe_buffer));
} else {
unsigned int tsize = pipe->ring_size - t;
if (h > 0)
memcpy(bufs + tsize, pipe->bufs,
h * sizeof(struct pipe_buffer));
memcpy(bufs, pipe->bufs + t,
tsize * sizeof(struct pipe_buffer));
}
}
head = n;
tail = 0;
kfree(pipe->bufs);
pipe->bufs = bufs;
pipe->ring_size = nr_slots;
if (pipe->max_usage > nr_slots)
pipe->max_usage = nr_slots;
pipe->tail = tail;
pipe->head = head;
spin_unlock_irq(&pipe->rd_wait.lock);
/* This might have made more room for writers */
wake_up_interruptible(&pipe->wr_wait);
return 0;
}
/*
* Allocate a new array of pipe buffers and copy the info over. Returns the
* pipe size if successful, or return -ERROR on error.
*/
static long pipe_set_size(struct pipe_inode_info *pipe, unsigned int arg)
{
unsigned long user_bufs;
unsigned int nr_slots, size;
long ret = 0;
#ifdef CONFIG_WATCH_QUEUE
if (pipe->watch_queue)
return -EBUSY;
#endif
size = round_pipe_size(arg);
nr_slots = size >> PAGE_SHIFT;
if (!nr_slots)
return -EINVAL;
/*
* If trying to increase the pipe capacity, check that an
* unprivileged user is not trying to exceed various limits
* (soft limit check here, hard limit check just below).
* Decreasing the pipe capacity is always permitted, even
* if the user is currently over a limit.
*/
if (nr_slots > pipe->max_usage &&
size > pipe_max_size && !capable(CAP_SYS_RESOURCE))
return -EPERM;
user_bufs = account_pipe_buffers(pipe->user, pipe->nr_accounted, nr_slots);
if (nr_slots > pipe->max_usage &&
(too_many_pipe_buffers_hard(user_bufs) ||
too_many_pipe_buffers_soft(user_bufs)) &&
pipe_is_unprivileged_user()) {
ret = -EPERM;
goto out_revert_acct;
}
ret = pipe_resize_ring(pipe, nr_slots);
if (ret < 0)
goto out_revert_acct;
pipe->max_usage = nr_slots;
pipe->nr_accounted = nr_slots;
return pipe->max_usage * PAGE_SIZE;
out_revert_acct:
(void) account_pipe_buffers(pipe->user, nr_slots, pipe->nr_accounted);
return ret;
}
/*
* Note that i_pipe and i_cdev share the same location, so checking ->i_pipe is
* not enough to verify that this is a pipe.
*/
struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice)
{
struct pipe_inode_info *pipe = file->private_data;
if (file->f_op != &pipefifo_fops || !pipe)
return NULL;
#ifdef CONFIG_WATCH_QUEUE
if (for_splice && pipe->watch_queue)
return NULL;
#endif
return pipe;
}
long pipe_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
{
struct pipe_inode_info *pipe;
long ret;
pipe = get_pipe_info(file, false);
if (!pipe)
return -EBADF;
__pipe_lock(pipe);
switch (cmd) {
case F_SETPIPE_SZ:
ret = pipe_set_size(pipe, arg);
break;
case F_GETPIPE_SZ:
ret = pipe->max_usage * PAGE_SIZE;
break;
default:
ret = -EINVAL;
break;
}
__pipe_unlock(pipe);
return ret;
}
static const struct super_operations pipefs_ops = {
.destroy_inode = free_inode_nonrcu,
.statfs = simple_statfs,
};
/*
* pipefs should _never_ be mounted by userland - too much of security hassle,
* no real gain from having the whole whorehouse mounted. So we don't need
* any operations on the root directory. However, we need a non-trivial
* d_name - pipe: will go nicely and kill the special-casing in procfs.
*/
static int pipefs_init_fs_context(struct fs_context *fc)
{
struct pseudo_fs_context *ctx = init_pseudo(fc, PIPEFS_MAGIC);
if (!ctx)
return -ENOMEM;
ctx->ops = &pipefs_ops;
ctx->dops = &pipefs_dentry_operations;
return 0;
}
static struct file_system_type pipe_fs_type = {
.name = "pipefs",
.init_fs_context = pipefs_init_fs_context,
.kill_sb = kill_anon_super,
};
#ifdef CONFIG_SYSCTL
static int do_proc_dopipe_max_size_conv(unsigned long *lvalp,
unsigned int *valp,
int write, void *data)
{
if (write) {
unsigned int val;
val = round_pipe_size(*lvalp);
if (val == 0)
return -EINVAL;
*valp = val;
} else {
unsigned int val = *valp;
*lvalp = (unsigned long) val;
}
return 0;
}
static int proc_dopipe_max_size(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return do_proc_douintvec(table, write, buffer, lenp, ppos,
do_proc_dopipe_max_size_conv, NULL);
}
static struct ctl_table fs_pipe_sysctls[] = {
{
.procname = "pipe-max-size",
.data = &pipe_max_size,
.maxlen = sizeof(pipe_max_size),
.mode = 0644,
.proc_handler = proc_dopipe_max_size,
},
{
.procname = "pipe-user-pages-hard",
.data = &pipe_user_pages_hard,
.maxlen = sizeof(pipe_user_pages_hard),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{
.procname = "pipe-user-pages-soft",
.data = &pipe_user_pages_soft,
.maxlen = sizeof(pipe_user_pages_soft),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{ }
};
#endif
static int __init init_pipe_fs(void)
{
int err = register_filesystem(&pipe_fs_type);
if (!err) {
pipe_mnt = kern_mount(&pipe_fs_type);
if (IS_ERR(pipe_mnt)) {
err = PTR_ERR(pipe_mnt);
unregister_filesystem(&pipe_fs_type);
}
}
#ifdef CONFIG_SYSCTL
register_sysctl_init("fs", fs_pipe_sysctls);
#endif
return err;
}
fs_initcall(init_pipe_fs);
| linux-master | fs/pipe.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/exec.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* #!-checking implemented by tytso.
*/
/*
* Demand-loading implemented 01.12.91 - no need to read anything but
* the header into memory. The inode of the executable is put into
* "current->executable", and page faults do the actual loading. Clean.
*
* Once more I can proudly say that linux stood up to being changed: it
* was less than 2 hours work to get demand-loading completely implemented.
*
* Demand loading changed July 1993 by Eric Youngdale. Use mmap instead,
* current->executable is only used by the procfs. This allows a dispatch
* table to check for several different types of binary formats. We keep
* trying until we recognize the file or we run out of supported binary
* formats.
*/
#include <linux/kernel_read_file.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/swap.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/sched/mm.h>
#include <linux/sched/coredump.h>
#include <linux/sched/signal.h>
#include <linux/sched/numa_balancing.h>
#include <linux/sched/task.h>
#include <linux/pagemap.h>
#include <linux/perf_event.h>
#include <linux/highmem.h>
#include <linux/spinlock.h>
#include <linux/key.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/utsname.h>
#include <linux/pid_namespace.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/tsacct_kern.h>
#include <linux/cn_proc.h>
#include <linux/audit.h>
#include <linux/kmod.h>
#include <linux/fsnotify.h>
#include <linux/fs_struct.h>
#include <linux/oom.h>
#include <linux/compat.h>
#include <linux/vmalloc.h>
#include <linux/io_uring.h>
#include <linux/syscall_user_dispatch.h>
#include <linux/coredump.h>
#include <linux/time_namespace.h>
#include <linux/user_events.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
#include <trace/events/task.h>
#include "internal.h"
#include <trace/events/sched.h>
static int bprm_creds_from_file(struct linux_binprm *bprm);
int suid_dumpable = 0;
static LIST_HEAD(formats);
static DEFINE_RWLOCK(binfmt_lock);
void __register_binfmt(struct linux_binfmt * fmt, int insert)
{
write_lock(&binfmt_lock);
insert ? list_add(&fmt->lh, &formats) :
list_add_tail(&fmt->lh, &formats);
write_unlock(&binfmt_lock);
}
EXPORT_SYMBOL(__register_binfmt);
void unregister_binfmt(struct linux_binfmt * fmt)
{
write_lock(&binfmt_lock);
list_del(&fmt->lh);
write_unlock(&binfmt_lock);
}
EXPORT_SYMBOL(unregister_binfmt);
static inline void put_binfmt(struct linux_binfmt * fmt)
{
module_put(fmt->module);
}
bool path_noexec(const struct path *path)
{
return (path->mnt->mnt_flags & MNT_NOEXEC) ||
(path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);
}
#ifdef CONFIG_USELIB
/*
* Note that a shared library must be both readable and executable due to
* security reasons.
*
* Also note that we take the address to load from the file itself.
*/
SYSCALL_DEFINE1(uselib, const char __user *, library)
{
struct linux_binfmt *fmt;
struct file *file;
struct filename *tmp = getname(library);
int error = PTR_ERR(tmp);
static const struct open_flags uselib_flags = {
.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
.acc_mode = MAY_READ | MAY_EXEC,
.intent = LOOKUP_OPEN,
.lookup_flags = LOOKUP_FOLLOW,
};
if (IS_ERR(tmp))
goto out;
file = do_filp_open(AT_FDCWD, tmp, &uselib_flags);
putname(tmp);
error = PTR_ERR(file);
if (IS_ERR(file))
goto out;
/*
* may_open() has already checked for this, so it should be
* impossible to trip now. But we need to be extra cautious
* and check again at the very end too.
*/
error = -EACCES;
if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
path_noexec(&file->f_path)))
goto exit;
error = -ENOEXEC;
read_lock(&binfmt_lock);
list_for_each_entry(fmt, &formats, lh) {
if (!fmt->load_shlib)
continue;
if (!try_module_get(fmt->module))
continue;
read_unlock(&binfmt_lock);
error = fmt->load_shlib(file);
read_lock(&binfmt_lock);
put_binfmt(fmt);
if (error != -ENOEXEC)
break;
}
read_unlock(&binfmt_lock);
exit:
fput(file);
out:
return error;
}
#endif /* #ifdef CONFIG_USELIB */
#ifdef CONFIG_MMU
/*
* The nascent bprm->mm is not visible until exec_mmap() but it can
* use a lot of memory, account these pages in current->mm temporary
* for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
* change the counter back via acct_arg_size(0).
*/
static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
{
struct mm_struct *mm = current->mm;
long diff = (long)(pages - bprm->vma_pages);
if (!mm || !diff)
return;
bprm->vma_pages = pages;
add_mm_counter(mm, MM_ANONPAGES, diff);
}
static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
int write)
{
struct page *page;
struct vm_area_struct *vma = bprm->vma;
struct mm_struct *mm = bprm->mm;
int ret;
/*
* Avoid relying on expanding the stack down in GUP (which
* does not work for STACK_GROWSUP anyway), and just do it
* by hand ahead of time.
*/
if (write && pos < vma->vm_start) {
mmap_write_lock(mm);
ret = expand_downwards(vma, pos);
if (unlikely(ret < 0)) {
mmap_write_unlock(mm);
return NULL;
}
mmap_write_downgrade(mm);
} else
mmap_read_lock(mm);
/*
* We are doing an exec(). 'current' is the process
* doing the exec and 'mm' is the new process's mm.
*/
ret = get_user_pages_remote(mm, pos, 1,
write ? FOLL_WRITE : 0,
&page, NULL);
mmap_read_unlock(mm);
if (ret <= 0)
return NULL;
if (write)
acct_arg_size(bprm, vma_pages(vma));
return page;
}
static void put_arg_page(struct page *page)
{
put_page(page);
}
static void free_arg_pages(struct linux_binprm *bprm)
{
}
static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
struct page *page)
{
flush_cache_page(bprm->vma, pos, page_to_pfn(page));
}
static int __bprm_mm_init(struct linux_binprm *bprm)
{
int err;
struct vm_area_struct *vma = NULL;
struct mm_struct *mm = bprm->mm;
bprm->vma = vma = vm_area_alloc(mm);
if (!vma)
return -ENOMEM;
vma_set_anonymous(vma);
if (mmap_write_lock_killable(mm)) {
err = -EINTR;
goto err_free;
}
/*
* Place the stack at the largest stack address the architecture
* supports. Later, we'll move this to an appropriate place. We don't
* use STACK_TOP because that can depend on attributes which aren't
* configured yet.
*/
BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
vma->vm_end = STACK_TOP_MAX;
vma->vm_start = vma->vm_end - PAGE_SIZE;
vm_flags_init(vma, VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP);
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
err = insert_vm_struct(mm, vma);
if (err)
goto err;
mm->stack_vm = mm->total_vm = 1;
mmap_write_unlock(mm);
bprm->p = vma->vm_end - sizeof(void *);
return 0;
err:
mmap_write_unlock(mm);
err_free:
bprm->vma = NULL;
vm_area_free(vma);
return err;
}
static bool valid_arg_len(struct linux_binprm *bprm, long len)
{
return len <= MAX_ARG_STRLEN;
}
#else
static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
{
}
static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
int write)
{
struct page *page;
page = bprm->page[pos / PAGE_SIZE];
if (!page && write) {
page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
if (!page)
return NULL;
bprm->page[pos / PAGE_SIZE] = page;
}
return page;
}
static void put_arg_page(struct page *page)
{
}
static void free_arg_page(struct linux_binprm *bprm, int i)
{
if (bprm->page[i]) {
__free_page(bprm->page[i]);
bprm->page[i] = NULL;
}
}
static void free_arg_pages(struct linux_binprm *bprm)
{
int i;
for (i = 0; i < MAX_ARG_PAGES; i++)
free_arg_page(bprm, i);
}
static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
struct page *page)
{
}
static int __bprm_mm_init(struct linux_binprm *bprm)
{
bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
return 0;
}
static bool valid_arg_len(struct linux_binprm *bprm, long len)
{
return len <= bprm->p;
}
#endif /* CONFIG_MMU */
/*
* Create a new mm_struct and populate it with a temporary stack
* vm_area_struct. We don't have enough context at this point to set the stack
* flags, permissions, and offset, so we use temporary values. We'll update
* them later in setup_arg_pages().
*/
static int bprm_mm_init(struct linux_binprm *bprm)
{
int err;
struct mm_struct *mm = NULL;
bprm->mm = mm = mm_alloc();
err = -ENOMEM;
if (!mm)
goto err;
/* Save current stack limit for all calculations made during exec. */
task_lock(current->group_leader);
bprm->rlim_stack = current->signal->rlim[RLIMIT_STACK];
task_unlock(current->group_leader);
err = __bprm_mm_init(bprm);
if (err)
goto err;
return 0;
err:
if (mm) {
bprm->mm = NULL;
mmdrop(mm);
}
return err;
}
struct user_arg_ptr {
#ifdef CONFIG_COMPAT
bool is_compat;
#endif
union {
const char __user *const __user *native;
#ifdef CONFIG_COMPAT
const compat_uptr_t __user *compat;
#endif
} ptr;
};
static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
{
const char __user *native;
#ifdef CONFIG_COMPAT
if (unlikely(argv.is_compat)) {
compat_uptr_t compat;
if (get_user(compat, argv.ptr.compat + nr))
return ERR_PTR(-EFAULT);
return compat_ptr(compat);
}
#endif
if (get_user(native, argv.ptr.native + nr))
return ERR_PTR(-EFAULT);
return native;
}
/*
* count() counts the number of strings in array ARGV.
*/
static int count(struct user_arg_ptr argv, int max)
{
int i = 0;
if (argv.ptr.native != NULL) {
for (;;) {
const char __user *p = get_user_arg_ptr(argv, i);
if (!p)
break;
if (IS_ERR(p))
return -EFAULT;
if (i >= max)
return -E2BIG;
++i;
if (fatal_signal_pending(current))
return -ERESTARTNOHAND;
cond_resched();
}
}
return i;
}
static int count_strings_kernel(const char *const *argv)
{
int i;
if (!argv)
return 0;
for (i = 0; argv[i]; ++i) {
if (i >= MAX_ARG_STRINGS)
return -E2BIG;
if (fatal_signal_pending(current))
return -ERESTARTNOHAND;
cond_resched();
}
return i;
}
static int bprm_stack_limits(struct linux_binprm *bprm)
{
unsigned long limit, ptr_size;
/*
* Limit to 1/4 of the max stack size or 3/4 of _STK_LIM
* (whichever is smaller) for the argv+env strings.
* This ensures that:
* - the remaining binfmt code will not run out of stack space,
* - the program will have a reasonable amount of stack left
* to work from.
*/
limit = _STK_LIM / 4 * 3;
limit = min(limit, bprm->rlim_stack.rlim_cur / 4);
/*
* We've historically supported up to 32 pages (ARG_MAX)
* of argument strings even with small stacks
*/
limit = max_t(unsigned long, limit, ARG_MAX);
/*
* We must account for the size of all the argv and envp pointers to
* the argv and envp strings, since they will also take up space in
* the stack. They aren't stored until much later when we can't
* signal to the parent that the child has run out of stack space.
* Instead, calculate it here so it's possible to fail gracefully.
*
* In the case of argc = 0, make sure there is space for adding a
* empty string (which will bump argc to 1), to ensure confused
* userspace programs don't start processing from argv[1], thinking
* argc can never be 0, to keep them from walking envp by accident.
* See do_execveat_common().
*/
ptr_size = (max(bprm->argc, 1) + bprm->envc) * sizeof(void *);
if (limit <= ptr_size)
return -E2BIG;
limit -= ptr_size;
bprm->argmin = bprm->p - limit;
return 0;
}
/*
* 'copy_strings()' copies argument/environment strings from the old
* processes's memory to the new process's stack. The call to get_user_pages()
* ensures the destination page is created and not swapped out.
*/
static int copy_strings(int argc, struct user_arg_ptr argv,
struct linux_binprm *bprm)
{
struct page *kmapped_page = NULL;
char *kaddr = NULL;
unsigned long kpos = 0;
int ret;
while (argc-- > 0) {
const char __user *str;
int len;
unsigned long pos;
ret = -EFAULT;
str = get_user_arg_ptr(argv, argc);
if (IS_ERR(str))
goto out;
len = strnlen_user(str, MAX_ARG_STRLEN);
if (!len)
goto out;
ret = -E2BIG;
if (!valid_arg_len(bprm, len))
goto out;
/* We're going to work our way backwards. */
pos = bprm->p;
str += len;
bprm->p -= len;
#ifdef CONFIG_MMU
if (bprm->p < bprm->argmin)
goto out;
#endif
while (len > 0) {
int offset, bytes_to_copy;
if (fatal_signal_pending(current)) {
ret = -ERESTARTNOHAND;
goto out;
}
cond_resched();
offset = pos % PAGE_SIZE;
if (offset == 0)
offset = PAGE_SIZE;
bytes_to_copy = offset;
if (bytes_to_copy > len)
bytes_to_copy = len;
offset -= bytes_to_copy;
pos -= bytes_to_copy;
str -= bytes_to_copy;
len -= bytes_to_copy;
if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
struct page *page;
page = get_arg_page(bprm, pos, 1);
if (!page) {
ret = -E2BIG;
goto out;
}
if (kmapped_page) {
flush_dcache_page(kmapped_page);
kunmap_local(kaddr);
put_arg_page(kmapped_page);
}
kmapped_page = page;
kaddr = kmap_local_page(kmapped_page);
kpos = pos & PAGE_MASK;
flush_arg_page(bprm, kpos, kmapped_page);
}
if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
ret = -EFAULT;
goto out;
}
}
}
ret = 0;
out:
if (kmapped_page) {
flush_dcache_page(kmapped_page);
kunmap_local(kaddr);
put_arg_page(kmapped_page);
}
return ret;
}
/*
* Copy and argument/environment string from the kernel to the processes stack.
*/
int copy_string_kernel(const char *arg, struct linux_binprm *bprm)
{
int len = strnlen(arg, MAX_ARG_STRLEN) + 1 /* terminating NUL */;
unsigned long pos = bprm->p;
if (len == 0)
return -EFAULT;
if (!valid_arg_len(bprm, len))
return -E2BIG;
/* We're going to work our way backwards. */
arg += len;
bprm->p -= len;
if (IS_ENABLED(CONFIG_MMU) && bprm->p < bprm->argmin)
return -E2BIG;
while (len > 0) {
unsigned int bytes_to_copy = min_t(unsigned int, len,
min_not_zero(offset_in_page(pos), PAGE_SIZE));
struct page *page;
pos -= bytes_to_copy;
arg -= bytes_to_copy;
len -= bytes_to_copy;
page = get_arg_page(bprm, pos, 1);
if (!page)
return -E2BIG;
flush_arg_page(bprm, pos & PAGE_MASK, page);
memcpy_to_page(page, offset_in_page(pos), arg, bytes_to_copy);
put_arg_page(page);
}
return 0;
}
EXPORT_SYMBOL(copy_string_kernel);
static int copy_strings_kernel(int argc, const char *const *argv,
struct linux_binprm *bprm)
{
while (argc-- > 0) {
int ret = copy_string_kernel(argv[argc], bprm);
if (ret < 0)
return ret;
if (fatal_signal_pending(current))
return -ERESTARTNOHAND;
cond_resched();
}
return 0;
}
#ifdef CONFIG_MMU
/*
* During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
* the binfmt code determines where the new stack should reside, we shift it to
* its final location. The process proceeds as follows:
*
* 1) Use shift to calculate the new vma endpoints.
* 2) Extend vma to cover both the old and new ranges. This ensures the
* arguments passed to subsequent functions are consistent.
* 3) Move vma's page tables to the new range.
* 4) Free up any cleared pgd range.
* 5) Shrink the vma to cover only the new range.
*/
static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long old_start = vma->vm_start;
unsigned long old_end = vma->vm_end;
unsigned long length = old_end - old_start;
unsigned long new_start = old_start - shift;
unsigned long new_end = old_end - shift;
VMA_ITERATOR(vmi, mm, new_start);
struct vm_area_struct *next;
struct mmu_gather tlb;
BUG_ON(new_start > new_end);
/*
* ensure there are no vmas between where we want to go
* and where we are
*/
if (vma != vma_next(&vmi))
return -EFAULT;
vma_iter_prev_range(&vmi);
/*
* cover the whole range: [new_start, old_end)
*/
if (vma_expand(&vmi, vma, new_start, old_end, vma->vm_pgoff, NULL))
return -ENOMEM;
/*
* move the page tables downwards, on failure we rely on
* process cleanup to remove whatever mess we made.
*/
if (length != move_page_tables(vma, old_start,
vma, new_start, length, false))
return -ENOMEM;
lru_add_drain();
tlb_gather_mmu(&tlb, mm);
next = vma_next(&vmi);
if (new_end > old_start) {
/*
* when the old and new regions overlap clear from new_end.
*/
free_pgd_range(&tlb, new_end, old_end, new_end,
next ? next->vm_start : USER_PGTABLES_CEILING);
} else {
/*
* otherwise, clean from old_start; this is done to not touch
* the address space in [new_end, old_start) some architectures
* have constraints on va-space that make this illegal (IA64) -
* for the others its just a little faster.
*/
free_pgd_range(&tlb, old_start, old_end, new_end,
next ? next->vm_start : USER_PGTABLES_CEILING);
}
tlb_finish_mmu(&tlb);
vma_prev(&vmi);
/* Shrink the vma to just the new range */
return vma_shrink(&vmi, vma, new_start, new_end, vma->vm_pgoff);
}
/*
* Finalizes the stack vm_area_struct. The flags and permissions are updated,
* the stack is optionally relocated, and some extra space is added.
*/
int setup_arg_pages(struct linux_binprm *bprm,
unsigned long stack_top,
int executable_stack)
{
unsigned long ret;
unsigned long stack_shift;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma = bprm->vma;
struct vm_area_struct *prev = NULL;
unsigned long vm_flags;
unsigned long stack_base;
unsigned long stack_size;
unsigned long stack_expand;
unsigned long rlim_stack;
struct mmu_gather tlb;
struct vma_iterator vmi;
#ifdef CONFIG_STACK_GROWSUP
/* Limit stack size */
stack_base = bprm->rlim_stack.rlim_max;
stack_base = calc_max_stack_size(stack_base);
/* Add space for stack randomization. */
stack_base += (STACK_RND_MASK << PAGE_SHIFT);
/* Make sure we didn't let the argument array grow too large. */
if (vma->vm_end - vma->vm_start > stack_base)
return -ENOMEM;
stack_base = PAGE_ALIGN(stack_top - stack_base);
stack_shift = vma->vm_start - stack_base;
mm->arg_start = bprm->p - stack_shift;
bprm->p = vma->vm_end - stack_shift;
#else
stack_top = arch_align_stack(stack_top);
stack_top = PAGE_ALIGN(stack_top);
if (unlikely(stack_top < mmap_min_addr) ||
unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
return -ENOMEM;
stack_shift = vma->vm_end - stack_top;
bprm->p -= stack_shift;
mm->arg_start = bprm->p;
#endif
if (bprm->loader)
bprm->loader -= stack_shift;
bprm->exec -= stack_shift;
if (mmap_write_lock_killable(mm))
return -EINTR;
vm_flags = VM_STACK_FLAGS;
/*
* Adjust stack execute permissions; explicitly enable for
* EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
* (arch default) otherwise.
*/
if (unlikely(executable_stack == EXSTACK_ENABLE_X))
vm_flags |= VM_EXEC;
else if (executable_stack == EXSTACK_DISABLE_X)
vm_flags &= ~VM_EXEC;
vm_flags |= mm->def_flags;
vm_flags |= VM_STACK_INCOMPLETE_SETUP;
vma_iter_init(&vmi, mm, vma->vm_start);
tlb_gather_mmu(&tlb, mm);
ret = mprotect_fixup(&vmi, &tlb, vma, &prev, vma->vm_start, vma->vm_end,
vm_flags);
tlb_finish_mmu(&tlb);
if (ret)
goto out_unlock;
BUG_ON(prev != vma);
if (unlikely(vm_flags & VM_EXEC)) {
pr_warn_once("process '%pD4' started with executable stack\n",
bprm->file);
}
/* Move stack pages down in memory. */
if (stack_shift) {
ret = shift_arg_pages(vma, stack_shift);
if (ret)
goto out_unlock;
}
/* mprotect_fixup is overkill to remove the temporary stack flags */
vm_flags_clear(vma, VM_STACK_INCOMPLETE_SETUP);
stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
stack_size = vma->vm_end - vma->vm_start;
/*
* Align this down to a page boundary as expand_stack
* will align it up.
*/
rlim_stack = bprm->rlim_stack.rlim_cur & PAGE_MASK;
stack_expand = min(rlim_stack, stack_size + stack_expand);
#ifdef CONFIG_STACK_GROWSUP
stack_base = vma->vm_start + stack_expand;
#else
stack_base = vma->vm_end - stack_expand;
#endif
current->mm->start_stack = bprm->p;
ret = expand_stack_locked(vma, stack_base);
if (ret)
ret = -EFAULT;
out_unlock:
mmap_write_unlock(mm);
return ret;
}
EXPORT_SYMBOL(setup_arg_pages);
#else
/*
* Transfer the program arguments and environment from the holding pages
* onto the stack. The provided stack pointer is adjusted accordingly.
*/
int transfer_args_to_stack(struct linux_binprm *bprm,
unsigned long *sp_location)
{
unsigned long index, stop, sp;
int ret = 0;
stop = bprm->p >> PAGE_SHIFT;
sp = *sp_location;
for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0;
char *src = kmap_local_page(bprm->page[index]) + offset;
sp -= PAGE_SIZE - offset;
if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0)
ret = -EFAULT;
kunmap_local(src);
if (ret)
goto out;
}
*sp_location = sp;
out:
return ret;
}
EXPORT_SYMBOL(transfer_args_to_stack);
#endif /* CONFIG_MMU */
static struct file *do_open_execat(int fd, struct filename *name, int flags)
{
struct file *file;
int err;
struct open_flags open_exec_flags = {
.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
.acc_mode = MAY_EXEC,
.intent = LOOKUP_OPEN,
.lookup_flags = LOOKUP_FOLLOW,
};
if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
return ERR_PTR(-EINVAL);
if (flags & AT_SYMLINK_NOFOLLOW)
open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
if (flags & AT_EMPTY_PATH)
open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
file = do_filp_open(fd, name, &open_exec_flags);
if (IS_ERR(file))
goto out;
/*
* may_open() has already checked for this, so it should be
* impossible to trip now. But we need to be extra cautious
* and check again at the very end too.
*/
err = -EACCES;
if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
path_noexec(&file->f_path)))
goto exit;
err = deny_write_access(file);
if (err)
goto exit;
out:
return file;
exit:
fput(file);
return ERR_PTR(err);
}
struct file *open_exec(const char *name)
{
struct filename *filename = getname_kernel(name);
struct file *f = ERR_CAST(filename);
if (!IS_ERR(filename)) {
f = do_open_execat(AT_FDCWD, filename, 0);
putname(filename);
}
return f;
}
EXPORT_SYMBOL(open_exec);
#if defined(CONFIG_BINFMT_FLAT) || defined(CONFIG_BINFMT_ELF_FDPIC)
ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
{
ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
if (res > 0)
flush_icache_user_range(addr, addr + len);
return res;
}
EXPORT_SYMBOL(read_code);
#endif
/*
* Maps the mm_struct mm into the current task struct.
* On success, this function returns with exec_update_lock
* held for writing.
*/
static int exec_mmap(struct mm_struct *mm)
{
struct task_struct *tsk;
struct mm_struct *old_mm, *active_mm;
int ret;
/* Notify parent that we're no longer interested in the old VM */
tsk = current;
old_mm = current->mm;
exec_mm_release(tsk, old_mm);
if (old_mm)
sync_mm_rss(old_mm);
ret = down_write_killable(&tsk->signal->exec_update_lock);
if (ret)
return ret;
if (old_mm) {
/*
* If there is a pending fatal signal perhaps a signal
* whose default action is to create a coredump get
* out and die instead of going through with the exec.
*/
ret = mmap_read_lock_killable(old_mm);
if (ret) {
up_write(&tsk->signal->exec_update_lock);
return ret;
}
}
task_lock(tsk);
membarrier_exec_mmap(mm);
local_irq_disable();
active_mm = tsk->active_mm;
tsk->active_mm = mm;
tsk->mm = mm;
mm_init_cid(mm);
/*
* This prevents preemption while active_mm is being loaded and
* it and mm are being updated, which could cause problems for
* lazy tlb mm refcounting when these are updated by context
* switches. Not all architectures can handle irqs off over
* activate_mm yet.
*/
if (!IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
local_irq_enable();
activate_mm(active_mm, mm);
if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
local_irq_enable();
lru_gen_add_mm(mm);
task_unlock(tsk);
lru_gen_use_mm(mm);
if (old_mm) {
mmap_read_unlock(old_mm);
BUG_ON(active_mm != old_mm);
setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm);
mm_update_next_owner(old_mm);
mmput(old_mm);
return 0;
}
mmdrop_lazy_tlb(active_mm);
return 0;
}
static int de_thread(struct task_struct *tsk)
{
struct signal_struct *sig = tsk->signal;
struct sighand_struct *oldsighand = tsk->sighand;
spinlock_t *lock = &oldsighand->siglock;
if (thread_group_empty(tsk))
goto no_thread_group;
/*
* Kill all other threads in the thread group.
*/
spin_lock_irq(lock);
if ((sig->flags & SIGNAL_GROUP_EXIT) || sig->group_exec_task) {
/*
* Another group action in progress, just
* return so that the signal is processed.
*/
spin_unlock_irq(lock);
return -EAGAIN;
}
sig->group_exec_task = tsk;
sig->notify_count = zap_other_threads(tsk);
if (!thread_group_leader(tsk))
sig->notify_count--;
while (sig->notify_count) {
__set_current_state(TASK_KILLABLE);
spin_unlock_irq(lock);
schedule();
if (__fatal_signal_pending(tsk))
goto killed;
spin_lock_irq(lock);
}
spin_unlock_irq(lock);
/*
* At this point all other threads have exited, all we have to
* do is to wait for the thread group leader to become inactive,
* and to assume its PID:
*/
if (!thread_group_leader(tsk)) {
struct task_struct *leader = tsk->group_leader;
for (;;) {
cgroup_threadgroup_change_begin(tsk);
write_lock_irq(&tasklist_lock);
/*
* Do this under tasklist_lock to ensure that
* exit_notify() can't miss ->group_exec_task
*/
sig->notify_count = -1;
if (likely(leader->exit_state))
break;
__set_current_state(TASK_KILLABLE);
write_unlock_irq(&tasklist_lock);
cgroup_threadgroup_change_end(tsk);
schedule();
if (__fatal_signal_pending(tsk))
goto killed;
}
/*
* The only record we have of the real-time age of a
* process, regardless of execs it's done, is start_time.
* All the past CPU time is accumulated in signal_struct
* from sister threads now dead. But in this non-leader
* exec, nothing survives from the original leader thread,
* whose birth marks the true age of this process now.
* When we take on its identity by switching to its PID, we
* also take its birthdate (always earlier than our own).
*/
tsk->start_time = leader->start_time;
tsk->start_boottime = leader->start_boottime;
BUG_ON(!same_thread_group(leader, tsk));
/*
* An exec() starts a new thread group with the
* TGID of the previous thread group. Rehash the
* two threads with a switched PID, and release
* the former thread group leader:
*/
/* Become a process group leader with the old leader's pid.
* The old leader becomes a thread of the this thread group.
*/
exchange_tids(tsk, leader);
transfer_pid(leader, tsk, PIDTYPE_TGID);
transfer_pid(leader, tsk, PIDTYPE_PGID);
transfer_pid(leader, tsk, PIDTYPE_SID);
list_replace_rcu(&leader->tasks, &tsk->tasks);
list_replace_init(&leader->sibling, &tsk->sibling);
tsk->group_leader = tsk;
leader->group_leader = tsk;
tsk->exit_signal = SIGCHLD;
leader->exit_signal = -1;
BUG_ON(leader->exit_state != EXIT_ZOMBIE);
leader->exit_state = EXIT_DEAD;
/*
* We are going to release_task()->ptrace_unlink() silently,
* the tracer can sleep in do_wait(). EXIT_DEAD guarantees
* the tracer won't block again waiting for this thread.
*/
if (unlikely(leader->ptrace))
__wake_up_parent(leader, leader->parent);
write_unlock_irq(&tasklist_lock);
cgroup_threadgroup_change_end(tsk);
release_task(leader);
}
sig->group_exec_task = NULL;
sig->notify_count = 0;
no_thread_group:
/* we have changed execution domain */
tsk->exit_signal = SIGCHLD;
BUG_ON(!thread_group_leader(tsk));
return 0;
killed:
/* protects against exit_notify() and __exit_signal() */
read_lock(&tasklist_lock);
sig->group_exec_task = NULL;
sig->notify_count = 0;
read_unlock(&tasklist_lock);
return -EAGAIN;
}
/*
* This function makes sure the current process has its own signal table,
* so that flush_signal_handlers can later reset the handlers without
* disturbing other processes. (Other processes might share the signal
* table via the CLONE_SIGHAND option to clone().)
*/
static int unshare_sighand(struct task_struct *me)
{
struct sighand_struct *oldsighand = me->sighand;
if (refcount_read(&oldsighand->count) != 1) {
struct sighand_struct *newsighand;
/*
* This ->sighand is shared with the CLONE_SIGHAND
* but not CLONE_THREAD task, switch to the new one.
*/
newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
if (!newsighand)
return -ENOMEM;
refcount_set(&newsighand->count, 1);
write_lock_irq(&tasklist_lock);
spin_lock(&oldsighand->siglock);
memcpy(newsighand->action, oldsighand->action,
sizeof(newsighand->action));
rcu_assign_pointer(me->sighand, newsighand);
spin_unlock(&oldsighand->siglock);
write_unlock_irq(&tasklist_lock);
__cleanup_sighand(oldsighand);
}
return 0;
}
char *__get_task_comm(char *buf, size_t buf_size, struct task_struct *tsk)
{
task_lock(tsk);
/* Always NUL terminated and zero-padded */
strscpy_pad(buf, tsk->comm, buf_size);
task_unlock(tsk);
return buf;
}
EXPORT_SYMBOL_GPL(__get_task_comm);
/*
* These functions flushes out all traces of the currently running executable
* so that a new one can be started
*/
void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
{
task_lock(tsk);
trace_task_rename(tsk, buf);
strscpy_pad(tsk->comm, buf, sizeof(tsk->comm));
task_unlock(tsk);
perf_event_comm(tsk, exec);
}
/*
* Calling this is the point of no return. None of the failures will be
* seen by userspace since either the process is already taking a fatal
* signal (via de_thread() or coredump), or will have SEGV raised
* (after exec_mmap()) by search_binary_handler (see below).
*/
int begin_new_exec(struct linux_binprm * bprm)
{
struct task_struct *me = current;
int retval;
/* Once we are committed compute the creds */
retval = bprm_creds_from_file(bprm);
if (retval)
return retval;
/*
* Ensure all future errors are fatal.
*/
bprm->point_of_no_return = true;
/*
* Make this the only thread in the thread group.
*/
retval = de_thread(me);
if (retval)
goto out;
/*
* Cancel any io_uring activity across execve
*/
io_uring_task_cancel();
/* Ensure the files table is not shared. */
retval = unshare_files();
if (retval)
goto out;
/*
* Must be called _before_ exec_mmap() as bprm->mm is
* not visible until then. Doing it here also ensures
* we don't race against replace_mm_exe_file().
*/
retval = set_mm_exe_file(bprm->mm, bprm->file);
if (retval)
goto out;
/* If the binary is not readable then enforce mm->dumpable=0 */
would_dump(bprm, bprm->file);
if (bprm->have_execfd)
would_dump(bprm, bprm->executable);
/*
* Release all of the old mmap stuff
*/
acct_arg_size(bprm, 0);
retval = exec_mmap(bprm->mm);
if (retval)
goto out;
bprm->mm = NULL;
retval = exec_task_namespaces();
if (retval)
goto out_unlock;
#ifdef CONFIG_POSIX_TIMERS
spin_lock_irq(&me->sighand->siglock);
posix_cpu_timers_exit(me);
spin_unlock_irq(&me->sighand->siglock);
exit_itimers(me);
flush_itimer_signals();
#endif
/*
* Make the signal table private.
*/
retval = unshare_sighand(me);
if (retval)
goto out_unlock;
me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC |
PF_NOFREEZE | PF_NO_SETAFFINITY);
flush_thread();
me->personality &= ~bprm->per_clear;
clear_syscall_work_syscall_user_dispatch(me);
/*
* We have to apply CLOEXEC before we change whether the process is
* dumpable (in setup_new_exec) to avoid a race with a process in userspace
* trying to access the should-be-closed file descriptors of a process
* undergoing exec(2).
*/
do_close_on_exec(me->files);
if (bprm->secureexec) {
/* Make sure parent cannot signal privileged process. */
me->pdeath_signal = 0;
/*
* For secureexec, reset the stack limit to sane default to
* avoid bad behavior from the prior rlimits. This has to
* happen before arch_pick_mmap_layout(), which examines
* RLIMIT_STACK, but after the point of no return to avoid
* needing to clean up the change on failure.
*/
if (bprm->rlim_stack.rlim_cur > _STK_LIM)
bprm->rlim_stack.rlim_cur = _STK_LIM;
}
me->sas_ss_sp = me->sas_ss_size = 0;
/*
* Figure out dumpability. Note that this checking only of current
* is wrong, but userspace depends on it. This should be testing
* bprm->secureexec instead.
*/
if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP ||
!(uid_eq(current_euid(), current_uid()) &&
gid_eq(current_egid(), current_gid())))
set_dumpable(current->mm, suid_dumpable);
else
set_dumpable(current->mm, SUID_DUMP_USER);
perf_event_exec();
__set_task_comm(me, kbasename(bprm->filename), true);
/* An exec changes our domain. We are no longer part of the thread
group */
WRITE_ONCE(me->self_exec_id, me->self_exec_id + 1);
flush_signal_handlers(me, 0);
retval = set_cred_ucounts(bprm->cred);
if (retval < 0)
goto out_unlock;
/*
* install the new credentials for this executable
*/
security_bprm_committing_creds(bprm);
commit_creds(bprm->cred);
bprm->cred = NULL;
/*
* Disable monitoring for regular users
* when executing setuid binaries. Must
* wait until new credentials are committed
* by commit_creds() above
*/
if (get_dumpable(me->mm) != SUID_DUMP_USER)
perf_event_exit_task(me);
/*
* cred_guard_mutex must be held at least to this point to prevent
* ptrace_attach() from altering our determination of the task's
* credentials; any time after this it may be unlocked.
*/
security_bprm_committed_creds(bprm);
/* Pass the opened binary to the interpreter. */
if (bprm->have_execfd) {
retval = get_unused_fd_flags(0);
if (retval < 0)
goto out_unlock;
fd_install(retval, bprm->executable);
bprm->executable = NULL;
bprm->execfd = retval;
}
return 0;
out_unlock:
up_write(&me->signal->exec_update_lock);
out:
return retval;
}
EXPORT_SYMBOL(begin_new_exec);
void would_dump(struct linux_binprm *bprm, struct file *file)
{
struct inode *inode = file_inode(file);
struct mnt_idmap *idmap = file_mnt_idmap(file);
if (inode_permission(idmap, inode, MAY_READ) < 0) {
struct user_namespace *old, *user_ns;
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
/* Ensure mm->user_ns contains the executable */
user_ns = old = bprm->mm->user_ns;
while ((user_ns != &init_user_ns) &&
!privileged_wrt_inode_uidgid(user_ns, idmap, inode))
user_ns = user_ns->parent;
if (old != user_ns) {
bprm->mm->user_ns = get_user_ns(user_ns);
put_user_ns(old);
}
}
}
EXPORT_SYMBOL(would_dump);
void setup_new_exec(struct linux_binprm * bprm)
{
/* Setup things that can depend upon the personality */
struct task_struct *me = current;
arch_pick_mmap_layout(me->mm, &bprm->rlim_stack);
arch_setup_new_exec();
/* Set the new mm task size. We have to do that late because it may
* depend on TIF_32BIT which is only updated in flush_thread() on
* some architectures like powerpc
*/
me->mm->task_size = TASK_SIZE;
up_write(&me->signal->exec_update_lock);
mutex_unlock(&me->signal->cred_guard_mutex);
}
EXPORT_SYMBOL(setup_new_exec);
/* Runs immediately before start_thread() takes over. */
void finalize_exec(struct linux_binprm *bprm)
{
/* Store any stack rlimit changes before starting thread. */
task_lock(current->group_leader);
current->signal->rlim[RLIMIT_STACK] = bprm->rlim_stack;
task_unlock(current->group_leader);
}
EXPORT_SYMBOL(finalize_exec);
/*
* Prepare credentials and lock ->cred_guard_mutex.
* setup_new_exec() commits the new creds and drops the lock.
* Or, if exec fails before, free_bprm() should release ->cred
* and unlock.
*/
static int prepare_bprm_creds(struct linux_binprm *bprm)
{
if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex))
return -ERESTARTNOINTR;
bprm->cred = prepare_exec_creds();
if (likely(bprm->cred))
return 0;
mutex_unlock(¤t->signal->cred_guard_mutex);
return -ENOMEM;
}
static void free_bprm(struct linux_binprm *bprm)
{
if (bprm->mm) {
acct_arg_size(bprm, 0);
mmput(bprm->mm);
}
free_arg_pages(bprm);
if (bprm->cred) {
mutex_unlock(¤t->signal->cred_guard_mutex);
abort_creds(bprm->cred);
}
if (bprm->file) {
allow_write_access(bprm->file);
fput(bprm->file);
}
if (bprm->executable)
fput(bprm->executable);
/* If a binfmt changed the interp, free it. */
if (bprm->interp != bprm->filename)
kfree(bprm->interp);
kfree(bprm->fdpath);
kfree(bprm);
}
static struct linux_binprm *alloc_bprm(int fd, struct filename *filename)
{
struct linux_binprm *bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
int retval = -ENOMEM;
if (!bprm)
goto out;
if (fd == AT_FDCWD || filename->name[0] == '/') {
bprm->filename = filename->name;
} else {
if (filename->name[0] == '\0')
bprm->fdpath = kasprintf(GFP_KERNEL, "/dev/fd/%d", fd);
else
bprm->fdpath = kasprintf(GFP_KERNEL, "/dev/fd/%d/%s",
fd, filename->name);
if (!bprm->fdpath)
goto out_free;
bprm->filename = bprm->fdpath;
}
bprm->interp = bprm->filename;
retval = bprm_mm_init(bprm);
if (retval)
goto out_free;
return bprm;
out_free:
free_bprm(bprm);
out:
return ERR_PTR(retval);
}
int bprm_change_interp(const char *interp, struct linux_binprm *bprm)
{
/* If a binfmt changed the interp, free it first. */
if (bprm->interp != bprm->filename)
kfree(bprm->interp);
bprm->interp = kstrdup(interp, GFP_KERNEL);
if (!bprm->interp)
return -ENOMEM;
return 0;
}
EXPORT_SYMBOL(bprm_change_interp);
/*
* determine how safe it is to execute the proposed program
* - the caller must hold ->cred_guard_mutex to protect against
* PTRACE_ATTACH or seccomp thread-sync
*/
static void check_unsafe_exec(struct linux_binprm *bprm)
{
struct task_struct *p = current, *t;
unsigned n_fs;
if (p->ptrace)
bprm->unsafe |= LSM_UNSAFE_PTRACE;
/*
* This isn't strictly necessary, but it makes it harder for LSMs to
* mess up.
*/
if (task_no_new_privs(current))
bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
/*
* If another task is sharing our fs, we cannot safely
* suid exec because the differently privileged task
* will be able to manipulate the current directory, etc.
* It would be nice to force an unshare instead...
*/
t = p;
n_fs = 1;
spin_lock(&p->fs->lock);
rcu_read_lock();
while_each_thread(p, t) {
if (t->fs == p->fs)
n_fs++;
}
rcu_read_unlock();
if (p->fs->users > n_fs)
bprm->unsafe |= LSM_UNSAFE_SHARE;
else
p->fs->in_exec = 1;
spin_unlock(&p->fs->lock);
}
static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file)
{
/* Handle suid and sgid on files */
struct mnt_idmap *idmap;
struct inode *inode = file_inode(file);
unsigned int mode;
vfsuid_t vfsuid;
vfsgid_t vfsgid;
if (!mnt_may_suid(file->f_path.mnt))
return;
if (task_no_new_privs(current))
return;
mode = READ_ONCE(inode->i_mode);
if (!(mode & (S_ISUID|S_ISGID)))
return;
idmap = file_mnt_idmap(file);
/* Be careful if suid/sgid is set */
inode_lock(inode);
/* reload atomically mode/uid/gid now that lock held */
mode = inode->i_mode;
vfsuid = i_uid_into_vfsuid(idmap, inode);
vfsgid = i_gid_into_vfsgid(idmap, inode);
inode_unlock(inode);
/* We ignore suid/sgid if there are no mappings for them in the ns */
if (!vfsuid_has_mapping(bprm->cred->user_ns, vfsuid) ||
!vfsgid_has_mapping(bprm->cred->user_ns, vfsgid))
return;
if (mode & S_ISUID) {
bprm->per_clear |= PER_CLEAR_ON_SETID;
bprm->cred->euid = vfsuid_into_kuid(vfsuid);
}
if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
bprm->per_clear |= PER_CLEAR_ON_SETID;
bprm->cred->egid = vfsgid_into_kgid(vfsgid);
}
}
/*
* Compute brpm->cred based upon the final binary.
*/
static int bprm_creds_from_file(struct linux_binprm *bprm)
{
/* Compute creds based on which file? */
struct file *file = bprm->execfd_creds ? bprm->executable : bprm->file;
bprm_fill_uid(bprm, file);
return security_bprm_creds_from_file(bprm, file);
}
/*
* Fill the binprm structure from the inode.
* Read the first BINPRM_BUF_SIZE bytes
*
* This may be called multiple times for binary chains (scripts for example).
*/
static int prepare_binprm(struct linux_binprm *bprm)
{
loff_t pos = 0;
memset(bprm->buf, 0, BINPRM_BUF_SIZE);
return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos);
}
/*
* Arguments are '\0' separated strings found at the location bprm->p
* points to; chop off the first by relocating brpm->p to right after
* the first '\0' encountered.
*/
int remove_arg_zero(struct linux_binprm *bprm)
{
int ret = 0;
unsigned long offset;
char *kaddr;
struct page *page;
if (!bprm->argc)
return 0;
do {
offset = bprm->p & ~PAGE_MASK;
page = get_arg_page(bprm, bprm->p, 0);
if (!page) {
ret = -EFAULT;
goto out;
}
kaddr = kmap_local_page(page);
for (; offset < PAGE_SIZE && kaddr[offset];
offset++, bprm->p++)
;
kunmap_local(kaddr);
put_arg_page(page);
} while (offset == PAGE_SIZE);
bprm->p++;
bprm->argc--;
ret = 0;
out:
return ret;
}
EXPORT_SYMBOL(remove_arg_zero);
#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
/*
* cycle the list of binary formats handler, until one recognizes the image
*/
static int search_binary_handler(struct linux_binprm *bprm)
{
bool need_retry = IS_ENABLED(CONFIG_MODULES);
struct linux_binfmt *fmt;
int retval;
retval = prepare_binprm(bprm);
if (retval < 0)
return retval;
retval = security_bprm_check(bprm);
if (retval)
return retval;
retval = -ENOENT;
retry:
read_lock(&binfmt_lock);
list_for_each_entry(fmt, &formats, lh) {
if (!try_module_get(fmt->module))
continue;
read_unlock(&binfmt_lock);
retval = fmt->load_binary(bprm);
read_lock(&binfmt_lock);
put_binfmt(fmt);
if (bprm->point_of_no_return || (retval != -ENOEXEC)) {
read_unlock(&binfmt_lock);
return retval;
}
}
read_unlock(&binfmt_lock);
if (need_retry) {
if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
printable(bprm->buf[2]) && printable(bprm->buf[3]))
return retval;
if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
return retval;
need_retry = false;
goto retry;
}
return retval;
}
/* binfmt handlers will call back into begin_new_exec() on success. */
static int exec_binprm(struct linux_binprm *bprm)
{
pid_t old_pid, old_vpid;
int ret, depth;
/* Need to fetch pid before load_binary changes it */
old_pid = current->pid;
rcu_read_lock();
old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
rcu_read_unlock();
/* This allows 4 levels of binfmt rewrites before failing hard. */
for (depth = 0;; depth++) {
struct file *exec;
if (depth > 5)
return -ELOOP;
ret = search_binary_handler(bprm);
if (ret < 0)
return ret;
if (!bprm->interpreter)
break;
exec = bprm->file;
bprm->file = bprm->interpreter;
bprm->interpreter = NULL;
allow_write_access(exec);
if (unlikely(bprm->have_execfd)) {
if (bprm->executable) {
fput(exec);
return -ENOEXEC;
}
bprm->executable = exec;
} else
fput(exec);
}
audit_bprm(bprm);
trace_sched_process_exec(current, old_pid, bprm);
ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
proc_exec_connector(current);
return 0;
}
/*
* sys_execve() executes a new program.
*/
static int bprm_execve(struct linux_binprm *bprm,
int fd, struct filename *filename, int flags)
{
struct file *file;
int retval;
retval = prepare_bprm_creds(bprm);
if (retval)
return retval;
/*
* Check for unsafe execution states before exec_binprm(), which
* will call back into begin_new_exec(), into bprm_creds_from_file(),
* where setuid-ness is evaluated.
*/
check_unsafe_exec(bprm);
current->in_execve = 1;
sched_mm_cid_before_execve(current);
file = do_open_execat(fd, filename, flags);
retval = PTR_ERR(file);
if (IS_ERR(file))
goto out_unmark;
sched_exec();
bprm->file = file;
/*
* Record that a name derived from an O_CLOEXEC fd will be
* inaccessible after exec. This allows the code in exec to
* choose to fail when the executable is not mmaped into the
* interpreter and an open file descriptor is not passed to
* the interpreter. This makes for a better user experience
* than having the interpreter start and then immediately fail
* when it finds the executable is inaccessible.
*/
if (bprm->fdpath && get_close_on_exec(fd))
bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;
/* Set the unchanging part of bprm->cred */
retval = security_bprm_creds_for_exec(bprm);
if (retval)
goto out;
retval = exec_binprm(bprm);
if (retval < 0)
goto out;
sched_mm_cid_after_execve(current);
/* execve succeeded */
current->fs->in_exec = 0;
current->in_execve = 0;
rseq_execve(current);
user_events_execve(current);
acct_update_integrals(current);
task_numa_free(current, false);
return retval;
out:
/*
* If past the point of no return ensure the code never
* returns to the userspace process. Use an existing fatal
* signal if present otherwise terminate the process with
* SIGSEGV.
*/
if (bprm->point_of_no_return && !fatal_signal_pending(current))
force_fatal_sig(SIGSEGV);
out_unmark:
sched_mm_cid_after_execve(current);
current->fs->in_exec = 0;
current->in_execve = 0;
return retval;
}
static int do_execveat_common(int fd, struct filename *filename,
struct user_arg_ptr argv,
struct user_arg_ptr envp,
int flags)
{
struct linux_binprm *bprm;
int retval;
if (IS_ERR(filename))
return PTR_ERR(filename);
/*
* We move the actual failure in case of RLIMIT_NPROC excess from
* set*uid() to execve() because too many poorly written programs
* don't check setuid() return code. Here we additionally recheck
* whether NPROC limit is still exceeded.
*/
if ((current->flags & PF_NPROC_EXCEEDED) &&
is_rlimit_overlimit(current_ucounts(), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
retval = -EAGAIN;
goto out_ret;
}
/* We're below the limit (still or again), so we don't want to make
* further execve() calls fail. */
current->flags &= ~PF_NPROC_EXCEEDED;
bprm = alloc_bprm(fd, filename);
if (IS_ERR(bprm)) {
retval = PTR_ERR(bprm);
goto out_ret;
}
retval = count(argv, MAX_ARG_STRINGS);
if (retval == 0)
pr_warn_once("process '%s' launched '%s' with NULL argv: empty string added\n",
current->comm, bprm->filename);
if (retval < 0)
goto out_free;
bprm->argc = retval;
retval = count(envp, MAX_ARG_STRINGS);
if (retval < 0)
goto out_free;
bprm->envc = retval;
retval = bprm_stack_limits(bprm);
if (retval < 0)
goto out_free;
retval = copy_string_kernel(bprm->filename, bprm);
if (retval < 0)
goto out_free;
bprm->exec = bprm->p;
retval = copy_strings(bprm->envc, envp, bprm);
if (retval < 0)
goto out_free;
retval = copy_strings(bprm->argc, argv, bprm);
if (retval < 0)
goto out_free;
/*
* When argv is empty, add an empty string ("") as argv[0] to
* ensure confused userspace programs that start processing
* from argv[1] won't end up walking envp. See also
* bprm_stack_limits().
*/
if (bprm->argc == 0) {
retval = copy_string_kernel("", bprm);
if (retval < 0)
goto out_free;
bprm->argc = 1;
}
retval = bprm_execve(bprm, fd, filename, flags);
out_free:
free_bprm(bprm);
out_ret:
putname(filename);
return retval;
}
int kernel_execve(const char *kernel_filename,
const char *const *argv, const char *const *envp)
{
struct filename *filename;
struct linux_binprm *bprm;
int fd = AT_FDCWD;
int retval;
/* It is non-sense for kernel threads to call execve */
if (WARN_ON_ONCE(current->flags & PF_KTHREAD))
return -EINVAL;
filename = getname_kernel(kernel_filename);
if (IS_ERR(filename))
return PTR_ERR(filename);
bprm = alloc_bprm(fd, filename);
if (IS_ERR(bprm)) {
retval = PTR_ERR(bprm);
goto out_ret;
}
retval = count_strings_kernel(argv);
if (WARN_ON_ONCE(retval == 0))
retval = -EINVAL;
if (retval < 0)
goto out_free;
bprm->argc = retval;
retval = count_strings_kernel(envp);
if (retval < 0)
goto out_free;
bprm->envc = retval;
retval = bprm_stack_limits(bprm);
if (retval < 0)
goto out_free;
retval = copy_string_kernel(bprm->filename, bprm);
if (retval < 0)
goto out_free;
bprm->exec = bprm->p;
retval = copy_strings_kernel(bprm->envc, envp, bprm);
if (retval < 0)
goto out_free;
retval = copy_strings_kernel(bprm->argc, argv, bprm);
if (retval < 0)
goto out_free;
retval = bprm_execve(bprm, fd, filename, 0);
out_free:
free_bprm(bprm);
out_ret:
putname(filename);
return retval;
}
static int do_execve(struct filename *filename,
const char __user *const __user *__argv,
const char __user *const __user *__envp)
{
struct user_arg_ptr argv = { .ptr.native = __argv };
struct user_arg_ptr envp = { .ptr.native = __envp };
return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
}
static int do_execveat(int fd, struct filename *filename,
const char __user *const __user *__argv,
const char __user *const __user *__envp,
int flags)
{
struct user_arg_ptr argv = { .ptr.native = __argv };
struct user_arg_ptr envp = { .ptr.native = __envp };
return do_execveat_common(fd, filename, argv, envp, flags);
}
#ifdef CONFIG_COMPAT
static int compat_do_execve(struct filename *filename,
const compat_uptr_t __user *__argv,
const compat_uptr_t __user *__envp)
{
struct user_arg_ptr argv = {
.is_compat = true,
.ptr.compat = __argv,
};
struct user_arg_ptr envp = {
.is_compat = true,
.ptr.compat = __envp,
};
return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
}
static int compat_do_execveat(int fd, struct filename *filename,
const compat_uptr_t __user *__argv,
const compat_uptr_t __user *__envp,
int flags)
{
struct user_arg_ptr argv = {
.is_compat = true,
.ptr.compat = __argv,
};
struct user_arg_ptr envp = {
.is_compat = true,
.ptr.compat = __envp,
};
return do_execveat_common(fd, filename, argv, envp, flags);
}
#endif
void set_binfmt(struct linux_binfmt *new)
{
struct mm_struct *mm = current->mm;
if (mm->binfmt)
module_put(mm->binfmt->module);
mm->binfmt = new;
if (new)
__module_get(new->module);
}
EXPORT_SYMBOL(set_binfmt);
/*
* set_dumpable stores three-value SUID_DUMP_* into mm->flags.
*/
void set_dumpable(struct mm_struct *mm, int value)
{
if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
return;
set_mask_bits(&mm->flags, MMF_DUMPABLE_MASK, value);
}
SYSCALL_DEFINE3(execve,
const char __user *, filename,
const char __user *const __user *, argv,
const char __user *const __user *, envp)
{
return do_execve(getname(filename), argv, envp);
}
SYSCALL_DEFINE5(execveat,
int, fd, const char __user *, filename,
const char __user *const __user *, argv,
const char __user *const __user *, envp,
int, flags)
{
return do_execveat(fd,
getname_uflags(filename, flags),
argv, envp, flags);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
const compat_uptr_t __user *, argv,
const compat_uptr_t __user *, envp)
{
return compat_do_execve(getname(filename), argv, envp);
}
COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
const char __user *, filename,
const compat_uptr_t __user *, argv,
const compat_uptr_t __user *, envp,
int, flags)
{
return compat_do_execveat(fd,
getname_uflags(filename, flags),
argv, envp, flags);
}
#endif
#ifdef CONFIG_SYSCTL
static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int error = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (!error)
validate_coredump_safety();
return error;
}
static struct ctl_table fs_exec_sysctls[] = {
{
.procname = "suid_dumpable",
.data = &suid_dumpable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax_coredump,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
},
{ }
};
static int __init init_fs_exec_sysctls(void)
{
register_sysctl_init("fs", fs_exec_sysctls);
return 0;
}
fs_initcall(init_fs_exec_sysctls);
#endif /* CONFIG_SYSCTL */
| linux-master | fs/exec.c |
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Christian Brauner <[email protected]> */
#include <linux/cred.h>
#include <linux/fs.h>
#include <linux/mnt_idmapping.h>
#include <linux/slab.h>
#include <linux/user_namespace.h>
#include "internal.h"
struct mnt_idmap {
struct user_namespace *owner;
refcount_t count;
};
/*
* Carries the initial idmapping of 0:0:4294967295 which is an identity
* mapping. This means that {g,u}id 0 is mapped to {g,u}id 0, {g,u}id 1 is
* mapped to {g,u}id 1, [...], {g,u}id 1000 to {g,u}id 1000, [...].
*/
struct mnt_idmap nop_mnt_idmap = {
.owner = &init_user_ns,
.count = REFCOUNT_INIT(1),
};
EXPORT_SYMBOL_GPL(nop_mnt_idmap);
/**
* check_fsmapping - check whether an mount idmapping is allowed
* @idmap: idmap of the relevent mount
* @sb: super block of the filesystem
*
* Return: true if @idmap is allowed, false if not.
*/
bool check_fsmapping(const struct mnt_idmap *idmap,
const struct super_block *sb)
{
return idmap->owner != sb->s_user_ns;
}
/**
* initial_idmapping - check whether this is the initial mapping
* @ns: idmapping to check
*
* Check whether this is the initial mapping, mapping 0 to 0, 1 to 1,
* [...], 1000 to 1000 [...].
*
* Return: true if this is the initial mapping, false if not.
*/
static inline bool initial_idmapping(const struct user_namespace *ns)
{
return ns == &init_user_ns;
}
/**
* no_idmapping - check whether we can skip remapping a kuid/gid
* @mnt_userns: the mount's idmapping
* @fs_userns: the filesystem's idmapping
*
* This function can be used to check whether a remapping between two
* idmappings is required.
* An idmapped mount is a mount that has an idmapping attached to it that
* is different from the filsystem's idmapping and the initial idmapping.
* If the initial mapping is used or the idmapping of the mount and the
* filesystem are identical no remapping is required.
*
* Return: true if remapping can be skipped, false if not.
*/
static inline bool no_idmapping(const struct user_namespace *mnt_userns,
const struct user_namespace *fs_userns)
{
return initial_idmapping(mnt_userns) || mnt_userns == fs_userns;
}
/**
* make_vfsuid - map a filesystem kuid according to an idmapping
* @idmap: the mount's idmapping
* @fs_userns: the filesystem's idmapping
* @kuid : kuid to be mapped
*
* Take a @kuid and remap it from @fs_userns into @idmap. Use this
* function when preparing a @kuid to be reported to userspace.
*
* If no_idmapping() determines that this is not an idmapped mount we can
* simply return @kuid unchanged.
* If initial_idmapping() tells us that the filesystem is not mounted with an
* idmapping we know the value of @kuid won't change when calling
* from_kuid() so we can simply retrieve the value via __kuid_val()
* directly.
*
* Return: @kuid mapped according to @idmap.
* If @kuid has no mapping in either @idmap or @fs_userns INVALID_UID is
* returned.
*/
vfsuid_t make_vfsuid(struct mnt_idmap *idmap,
struct user_namespace *fs_userns,
kuid_t kuid)
{
uid_t uid;
struct user_namespace *mnt_userns = idmap->owner;
if (no_idmapping(mnt_userns, fs_userns))
return VFSUIDT_INIT(kuid);
if (initial_idmapping(fs_userns))
uid = __kuid_val(kuid);
else
uid = from_kuid(fs_userns, kuid);
if (uid == (uid_t)-1)
return INVALID_VFSUID;
return VFSUIDT_INIT(make_kuid(mnt_userns, uid));
}
EXPORT_SYMBOL_GPL(make_vfsuid);
/**
* make_vfsgid - map a filesystem kgid according to an idmapping
* @idmap: the mount's idmapping
* @fs_userns: the filesystem's idmapping
* @kgid : kgid to be mapped
*
* Take a @kgid and remap it from @fs_userns into @idmap. Use this
* function when preparing a @kgid to be reported to userspace.
*
* If no_idmapping() determines that this is not an idmapped mount we can
* simply return @kgid unchanged.
* If initial_idmapping() tells us that the filesystem is not mounted with an
* idmapping we know the value of @kgid won't change when calling
* from_kgid() so we can simply retrieve the value via __kgid_val()
* directly.
*
* Return: @kgid mapped according to @idmap.
* If @kgid has no mapping in either @idmap or @fs_userns INVALID_GID is
* returned.
*/
vfsgid_t make_vfsgid(struct mnt_idmap *idmap,
struct user_namespace *fs_userns, kgid_t kgid)
{
gid_t gid;
struct user_namespace *mnt_userns = idmap->owner;
if (no_idmapping(mnt_userns, fs_userns))
return VFSGIDT_INIT(kgid);
if (initial_idmapping(fs_userns))
gid = __kgid_val(kgid);
else
gid = from_kgid(fs_userns, kgid);
if (gid == (gid_t)-1)
return INVALID_VFSGID;
return VFSGIDT_INIT(make_kgid(mnt_userns, gid));
}
EXPORT_SYMBOL_GPL(make_vfsgid);
/**
* from_vfsuid - map a vfsuid into the filesystem idmapping
* @idmap: the mount's idmapping
* @fs_userns: the filesystem's idmapping
* @vfsuid : vfsuid to be mapped
*
* Map @vfsuid into the filesystem idmapping. This function has to be used in
* order to e.g. write @vfsuid to inode->i_uid.
*
* Return: @vfsuid mapped into the filesystem idmapping
*/
kuid_t from_vfsuid(struct mnt_idmap *idmap,
struct user_namespace *fs_userns, vfsuid_t vfsuid)
{
uid_t uid;
struct user_namespace *mnt_userns = idmap->owner;
if (no_idmapping(mnt_userns, fs_userns))
return AS_KUIDT(vfsuid);
uid = from_kuid(mnt_userns, AS_KUIDT(vfsuid));
if (uid == (uid_t)-1)
return INVALID_UID;
if (initial_idmapping(fs_userns))
return KUIDT_INIT(uid);
return make_kuid(fs_userns, uid);
}
EXPORT_SYMBOL_GPL(from_vfsuid);
/**
* from_vfsgid - map a vfsgid into the filesystem idmapping
* @idmap: the mount's idmapping
* @fs_userns: the filesystem's idmapping
* @vfsgid : vfsgid to be mapped
*
* Map @vfsgid into the filesystem idmapping. This function has to be used in
* order to e.g. write @vfsgid to inode->i_gid.
*
* Return: @vfsgid mapped into the filesystem idmapping
*/
kgid_t from_vfsgid(struct mnt_idmap *idmap,
struct user_namespace *fs_userns, vfsgid_t vfsgid)
{
gid_t gid;
struct user_namespace *mnt_userns = idmap->owner;
if (no_idmapping(mnt_userns, fs_userns))
return AS_KGIDT(vfsgid);
gid = from_kgid(mnt_userns, AS_KGIDT(vfsgid));
if (gid == (gid_t)-1)
return INVALID_GID;
if (initial_idmapping(fs_userns))
return KGIDT_INIT(gid);
return make_kgid(fs_userns, gid);
}
EXPORT_SYMBOL_GPL(from_vfsgid);
#ifdef CONFIG_MULTIUSER
/**
* vfsgid_in_group_p() - check whether a vfsuid matches the caller's groups
* @vfsgid: the mnt gid to match
*
* This function can be used to determine whether @vfsuid matches any of the
* caller's groups.
*
* Return: 1 if vfsuid matches caller's groups, 0 if not.
*/
int vfsgid_in_group_p(vfsgid_t vfsgid)
{
return in_group_p(AS_KGIDT(vfsgid));
}
#else
int vfsgid_in_group_p(vfsgid_t vfsgid)
{
return 1;
}
#endif
EXPORT_SYMBOL_GPL(vfsgid_in_group_p);
struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns)
{
struct mnt_idmap *idmap;
idmap = kzalloc(sizeof(struct mnt_idmap), GFP_KERNEL_ACCOUNT);
if (!idmap)
return ERR_PTR(-ENOMEM);
idmap->owner = get_user_ns(mnt_userns);
refcount_set(&idmap->count, 1);
return idmap;
}
/**
* mnt_idmap_get - get a reference to an idmapping
* @idmap: the idmap to bump the reference on
*
* If @idmap is not the @nop_mnt_idmap bump the reference count.
*
* Return: @idmap with reference count bumped if @not_mnt_idmap isn't passed.
*/
struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap)
{
if (idmap != &nop_mnt_idmap)
refcount_inc(&idmap->count);
return idmap;
}
/**
* mnt_idmap_put - put a reference to an idmapping
* @idmap: the idmap to put the reference on
*
* If this is a non-initial idmapping, put the reference count when a mount is
* released and free it if we're the last user.
*/
void mnt_idmap_put(struct mnt_idmap *idmap)
{
if (idmap != &nop_mnt_idmap && refcount_dec_and_test(&idmap->count)) {
put_user_ns(idmap->owner);
kfree(idmap);
}
}
| linux-master | fs/mnt_idmapping.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/fs_stack.h>
/* does _NOT_ require i_mutex to be held.
*
* This function cannot be inlined since i_size_{read,write} is rather
* heavy-weight on 32-bit systems
*/
void fsstack_copy_inode_size(struct inode *dst, struct inode *src)
{
loff_t i_size;
blkcnt_t i_blocks;
/*
* i_size_read() includes its own seqlocking and protection from
* preemption (see include/linux/fs.h): we need nothing extra for
* that here, and prefer to avoid nesting locks than attempt to keep
* i_size and i_blocks in sync together.
*/
i_size = i_size_read(src);
/*
* But on 32-bit, we ought to make an effort to keep the two halves of
* i_blocks in sync despite SMP or PREEMPTION - though stat's
* generic_fillattr() doesn't bother, and we won't be applying quotas
* (where i_blocks does become important) at the upper level.
*
* We don't actually know what locking is used at the lower level;
* but if it's a filesystem that supports quotas, it will be using
* i_lock as in inode_add_bytes().
*/
if (sizeof(i_blocks) > sizeof(long))
spin_lock(&src->i_lock);
i_blocks = src->i_blocks;
if (sizeof(i_blocks) > sizeof(long))
spin_unlock(&src->i_lock);
/*
* If CONFIG_SMP or CONFIG_PREEMPTION on 32-bit, it's vital for
* fsstack_copy_inode_size() to hold some lock around
* i_size_write(), otherwise i_size_read() may spin forever (see
* include/linux/fs.h). We don't necessarily hold i_mutex when this
* is called, so take i_lock for that case.
*
* And if on 32-bit, continue our effort to keep the two halves of
* i_blocks in sync despite SMP or PREEMPTION: use i_lock for that case
* too, and do both at once by combining the tests.
*
* There is none of this locking overhead in the 64-bit case.
*/
if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
spin_lock(&dst->i_lock);
i_size_write(dst, i_size);
dst->i_blocks = i_blocks;
if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
spin_unlock(&dst->i_lock);
}
EXPORT_SYMBOL_GPL(fsstack_copy_inode_size);
/* copy all attributes */
void fsstack_copy_attr_all(struct inode *dest, const struct inode *src)
{
dest->i_mode = src->i_mode;
dest->i_uid = src->i_uid;
dest->i_gid = src->i_gid;
dest->i_rdev = src->i_rdev;
dest->i_atime = src->i_atime;
dest->i_mtime = src->i_mtime;
inode_set_ctime_to_ts(dest, inode_get_ctime(src));
dest->i_blkbits = src->i_blkbits;
dest->i_flags = src->i_flags;
set_nlink(dest, src->i_nlink);
}
EXPORT_SYMBOL_GPL(fsstack_copy_attr_all);
| linux-master | fs/stack.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/exportfs.h>
#include <linux/fs_struct.h>
#include <linux/fsnotify.h>
#include <linux/personality.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
#include "internal.h"
#include "mount.h"
static long do_sys_name_to_handle(const struct path *path,
struct file_handle __user *ufh,
int __user *mnt_id, int fh_flags)
{
long retval;
struct file_handle f_handle;
int handle_dwords, handle_bytes;
struct file_handle *handle = NULL;
/*
* We need to make sure whether the file system support decoding of
* the file handle if decodeable file handle was requested.
* Otherwise, even empty export_operations are sufficient to opt-in
* to encoding FIDs.
*/
if (!path->dentry->d_sb->s_export_op ||
(!(fh_flags & EXPORT_FH_FID) &&
!path->dentry->d_sb->s_export_op->fh_to_dentry))
return -EOPNOTSUPP;
if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle)))
return -EFAULT;
if (f_handle.handle_bytes > MAX_HANDLE_SZ)
return -EINVAL;
handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
GFP_KERNEL);
if (!handle)
return -ENOMEM;
/* convert handle size to multiple of sizeof(u32) */
handle_dwords = f_handle.handle_bytes >> 2;
/* we ask for a non connectable maybe decodeable file handle */
retval = exportfs_encode_fh(path->dentry,
(struct fid *)handle->f_handle,
&handle_dwords, fh_flags);
handle->handle_type = retval;
/* convert handle size to bytes */
handle_bytes = handle_dwords * sizeof(u32);
handle->handle_bytes = handle_bytes;
if ((handle->handle_bytes > f_handle.handle_bytes) ||
(retval == FILEID_INVALID) || (retval < 0)) {
/* As per old exportfs_encode_fh documentation
* we could return ENOSPC to indicate overflow
* But file system returned 255 always. So handle
* both the values
*/
if (retval == FILEID_INVALID || retval == -ENOSPC)
retval = -EOVERFLOW;
/*
* set the handle size to zero so we copy only
* non variable part of the file_handle
*/
handle_bytes = 0;
} else
retval = 0;
/* copy the mount id */
if (put_user(real_mount(path->mnt)->mnt_id, mnt_id) ||
copy_to_user(ufh, handle,
sizeof(struct file_handle) + handle_bytes))
retval = -EFAULT;
kfree(handle);
return retval;
}
/**
* sys_name_to_handle_at: convert name to handle
* @dfd: directory relative to which name is interpreted if not absolute
* @name: name that should be converted to handle.
* @handle: resulting file handle
* @mnt_id: mount id of the file system containing the file
* @flag: flag value to indicate whether to follow symlink or not
* and whether a decodable file handle is required.
*
* @handle->handle_size indicate the space available to store the
* variable part of the file handle in bytes. If there is not
* enough space, the field is updated to return the minimum
* value required.
*/
SYSCALL_DEFINE5(name_to_handle_at, int, dfd, const char __user *, name,
struct file_handle __user *, handle, int __user *, mnt_id,
int, flag)
{
struct path path;
int lookup_flags;
int fh_flags;
int err;
if (flag & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH | AT_HANDLE_FID))
return -EINVAL;
lookup_flags = (flag & AT_SYMLINK_FOLLOW) ? LOOKUP_FOLLOW : 0;
fh_flags = (flag & AT_HANDLE_FID) ? EXPORT_FH_FID : 0;
if (flag & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
err = user_path_at(dfd, name, lookup_flags, &path);
if (!err) {
err = do_sys_name_to_handle(&path, handle, mnt_id, fh_flags);
path_put(&path);
}
return err;
}
static struct vfsmount *get_vfsmount_from_fd(int fd)
{
struct vfsmount *mnt;
if (fd == AT_FDCWD) {
struct fs_struct *fs = current->fs;
spin_lock(&fs->lock);
mnt = mntget(fs->pwd.mnt);
spin_unlock(&fs->lock);
} else {
struct fd f = fdget(fd);
if (!f.file)
return ERR_PTR(-EBADF);
mnt = mntget(f.file->f_path.mnt);
fdput(f);
}
return mnt;
}
static int vfs_dentry_acceptable(void *context, struct dentry *dentry)
{
return 1;
}
static int do_handle_to_path(int mountdirfd, struct file_handle *handle,
struct path *path)
{
int retval = 0;
int handle_dwords;
path->mnt = get_vfsmount_from_fd(mountdirfd);
if (IS_ERR(path->mnt)) {
retval = PTR_ERR(path->mnt);
goto out_err;
}
/* change the handle size to multiple of sizeof(u32) */
handle_dwords = handle->handle_bytes >> 2;
path->dentry = exportfs_decode_fh(path->mnt,
(struct fid *)handle->f_handle,
handle_dwords, handle->handle_type,
vfs_dentry_acceptable, NULL);
if (IS_ERR(path->dentry)) {
retval = PTR_ERR(path->dentry);
goto out_mnt;
}
return 0;
out_mnt:
mntput(path->mnt);
out_err:
return retval;
}
static int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
struct path *path)
{
int retval = 0;
struct file_handle f_handle;
struct file_handle *handle = NULL;
/*
* With handle we don't look at the execute bit on the
* directory. Ideally we would like CAP_DAC_SEARCH.
* But we don't have that
*/
if (!capable(CAP_DAC_READ_SEARCH)) {
retval = -EPERM;
goto out_err;
}
if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle))) {
retval = -EFAULT;
goto out_err;
}
if ((f_handle.handle_bytes > MAX_HANDLE_SZ) ||
(f_handle.handle_bytes == 0)) {
retval = -EINVAL;
goto out_err;
}
handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
GFP_KERNEL);
if (!handle) {
retval = -ENOMEM;
goto out_err;
}
/* copy the full handle */
*handle = f_handle;
if (copy_from_user(&handle->f_handle,
&ufh->f_handle,
f_handle.handle_bytes)) {
retval = -EFAULT;
goto out_handle;
}
retval = do_handle_to_path(mountdirfd, handle, path);
out_handle:
kfree(handle);
out_err:
return retval;
}
static long do_handle_open(int mountdirfd, struct file_handle __user *ufh,
int open_flag)
{
long retval = 0;
struct path path;
struct file *file;
int fd;
retval = handle_to_path(mountdirfd, ufh, &path);
if (retval)
return retval;
fd = get_unused_fd_flags(open_flag);
if (fd < 0) {
path_put(&path);
return fd;
}
file = file_open_root(&path, "", open_flag, 0);
if (IS_ERR(file)) {
put_unused_fd(fd);
retval = PTR_ERR(file);
} else {
retval = fd;
fd_install(fd, file);
}
path_put(&path);
return retval;
}
/**
* sys_open_by_handle_at: Open the file handle
* @mountdirfd: directory file descriptor
* @handle: file handle to be opened
* @flags: open flags.
*
* @mountdirfd indicate the directory file descriptor
* of the mount point. file handle is decoded relative
* to the vfsmount pointed by the @mountdirfd. @flags
* value is same as the open(2) flags.
*/
SYSCALL_DEFINE3(open_by_handle_at, int, mountdirfd,
struct file_handle __user *, handle,
int, flags)
{
long ret;
if (force_o_largefile())
flags |= O_LARGEFILE;
ret = do_handle_open(mountdirfd, handle, flags);
return ret;
}
#ifdef CONFIG_COMPAT
/*
* Exactly like fs/open.c:sys_open_by_handle_at(), except that it
* doesn't set the O_LARGEFILE flag.
*/
COMPAT_SYSCALL_DEFINE3(open_by_handle_at, int, mountdirfd,
struct file_handle __user *, handle, int, flags)
{
return do_handle_open(mountdirfd, handle, flags);
}
#endif
| linux-master | fs/fhandle.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/freezer.h>
#include <linux/mm.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/swap.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/perf_event.h>
#include <linux/highmem.h>
#include <linux/spinlock.h>
#include <linux/key.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/coredump.h>
#include <linux/sched/coredump.h>
#include <linux/sched/signal.h>
#include <linux/sched/task_stack.h>
#include <linux/utsname.h>
#include <linux/pid_namespace.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/tsacct_kern.h>
#include <linux/cn_proc.h>
#include <linux/audit.h>
#include <linux/kmod.h>
#include <linux/fsnotify.h>
#include <linux/fs_struct.h>
#include <linux/pipe_fs_i.h>
#include <linux/oom.h>
#include <linux/compat.h>
#include <linux/fs.h>
#include <linux/path.h>
#include <linux/timekeeping.h>
#include <linux/sysctl.h>
#include <linux/elf.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
#include <asm/exec.h>
#include <trace/events/task.h>
#include "internal.h"
#include <trace/events/sched.h>
static bool dump_vma_snapshot(struct coredump_params *cprm);
static void free_vma_snapshot(struct coredump_params *cprm);
static int core_uses_pid;
static unsigned int core_pipe_limit;
static char core_pattern[CORENAME_MAX_SIZE] = "core";
static int core_name_size = CORENAME_MAX_SIZE;
struct core_name {
char *corename;
int used, size;
};
static int expand_corename(struct core_name *cn, int size)
{
char *corename;
size = kmalloc_size_roundup(size);
corename = krealloc(cn->corename, size, GFP_KERNEL);
if (!corename)
return -ENOMEM;
if (size > core_name_size) /* racy but harmless */
core_name_size = size;
cn->size = size;
cn->corename = corename;
return 0;
}
static __printf(2, 0) int cn_vprintf(struct core_name *cn, const char *fmt,
va_list arg)
{
int free, need;
va_list arg_copy;
again:
free = cn->size - cn->used;
va_copy(arg_copy, arg);
need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
va_end(arg_copy);
if (need < free) {
cn->used += need;
return 0;
}
if (!expand_corename(cn, cn->size + need - free + 1))
goto again;
return -ENOMEM;
}
static __printf(2, 3) int cn_printf(struct core_name *cn, const char *fmt, ...)
{
va_list arg;
int ret;
va_start(arg, fmt);
ret = cn_vprintf(cn, fmt, arg);
va_end(arg);
return ret;
}
static __printf(2, 3)
int cn_esc_printf(struct core_name *cn, const char *fmt, ...)
{
int cur = cn->used;
va_list arg;
int ret;
va_start(arg, fmt);
ret = cn_vprintf(cn, fmt, arg);
va_end(arg);
if (ret == 0) {
/*
* Ensure that this coredump name component can't cause the
* resulting corefile path to consist of a ".." or ".".
*/
if ((cn->used - cur == 1 && cn->corename[cur] == '.') ||
(cn->used - cur == 2 && cn->corename[cur] == '.'
&& cn->corename[cur+1] == '.'))
cn->corename[cur] = '!';
/*
* Empty names are fishy and could be used to create a "//" in a
* corefile name, causing the coredump to happen one directory
* level too high. Enforce that all components of the core
* pattern are at least one character long.
*/
if (cn->used == cur)
ret = cn_printf(cn, "!");
}
for (; cur < cn->used; ++cur) {
if (cn->corename[cur] == '/')
cn->corename[cur] = '!';
}
return ret;
}
static int cn_print_exe_file(struct core_name *cn, bool name_only)
{
struct file *exe_file;
char *pathbuf, *path, *ptr;
int ret;
exe_file = get_mm_exe_file(current->mm);
if (!exe_file)
return cn_esc_printf(cn, "%s (path unknown)", current->comm);
pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
if (!pathbuf) {
ret = -ENOMEM;
goto put_exe_file;
}
path = file_path(exe_file, pathbuf, PATH_MAX);
if (IS_ERR(path)) {
ret = PTR_ERR(path);
goto free_buf;
}
if (name_only) {
ptr = strrchr(path, '/');
if (ptr)
path = ptr + 1;
}
ret = cn_esc_printf(cn, "%s", path);
free_buf:
kfree(pathbuf);
put_exe_file:
fput(exe_file);
return ret;
}
/* format_corename will inspect the pattern parameter, and output a
* name into corename, which must have space for at least
* CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
*/
static int format_corename(struct core_name *cn, struct coredump_params *cprm,
size_t **argv, int *argc)
{
const struct cred *cred = current_cred();
const char *pat_ptr = core_pattern;
int ispipe = (*pat_ptr == '|');
bool was_space = false;
int pid_in_pattern = 0;
int err = 0;
cn->used = 0;
cn->corename = NULL;
if (expand_corename(cn, core_name_size))
return -ENOMEM;
cn->corename[0] = '\0';
if (ispipe) {
int argvs = sizeof(core_pattern) / 2;
(*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL);
if (!(*argv))
return -ENOMEM;
(*argv)[(*argc)++] = 0;
++pat_ptr;
if (!(*pat_ptr))
return -ENOMEM;
}
/* Repeat as long as we have more pattern to process and more output
space */
while (*pat_ptr) {
/*
* Split on spaces before doing template expansion so that
* %e and %E don't get split if they have spaces in them
*/
if (ispipe) {
if (isspace(*pat_ptr)) {
if (cn->used != 0)
was_space = true;
pat_ptr++;
continue;
} else if (was_space) {
was_space = false;
err = cn_printf(cn, "%c", '\0');
if (err)
return err;
(*argv)[(*argc)++] = cn->used;
}
}
if (*pat_ptr != '%') {
err = cn_printf(cn, "%c", *pat_ptr++);
} else {
switch (*++pat_ptr) {
/* single % at the end, drop that */
case 0:
goto out;
/* Double percent, output one percent */
case '%':
err = cn_printf(cn, "%c", '%');
break;
/* pid */
case 'p':
pid_in_pattern = 1;
err = cn_printf(cn, "%d",
task_tgid_vnr(current));
break;
/* global pid */
case 'P':
err = cn_printf(cn, "%d",
task_tgid_nr(current));
break;
case 'i':
err = cn_printf(cn, "%d",
task_pid_vnr(current));
break;
case 'I':
err = cn_printf(cn, "%d",
task_pid_nr(current));
break;
/* uid */
case 'u':
err = cn_printf(cn, "%u",
from_kuid(&init_user_ns,
cred->uid));
break;
/* gid */
case 'g':
err = cn_printf(cn, "%u",
from_kgid(&init_user_ns,
cred->gid));
break;
case 'd':
err = cn_printf(cn, "%d",
__get_dumpable(cprm->mm_flags));
break;
/* signal that caused the coredump */
case 's':
err = cn_printf(cn, "%d",
cprm->siginfo->si_signo);
break;
/* UNIX time of coredump */
case 't': {
time64_t time;
time = ktime_get_real_seconds();
err = cn_printf(cn, "%lld", time);
break;
}
/* hostname */
case 'h':
down_read(&uts_sem);
err = cn_esc_printf(cn, "%s",
utsname()->nodename);
up_read(&uts_sem);
break;
/* executable, could be changed by prctl PR_SET_NAME etc */
case 'e':
err = cn_esc_printf(cn, "%s", current->comm);
break;
/* file name of executable */
case 'f':
err = cn_print_exe_file(cn, true);
break;
case 'E':
err = cn_print_exe_file(cn, false);
break;
/* core limit size */
case 'c':
err = cn_printf(cn, "%lu",
rlimit(RLIMIT_CORE));
break;
/* CPU the task ran on */
case 'C':
err = cn_printf(cn, "%d", cprm->cpu);
break;
default:
break;
}
++pat_ptr;
}
if (err)
return err;
}
out:
/* Backward compatibility with core_uses_pid:
*
* If core_pattern does not include a %p (as is the default)
* and core_uses_pid is set, then .%pid will be appended to
* the filename. Do not do this for piped commands. */
if (!ispipe && !pid_in_pattern && core_uses_pid) {
err = cn_printf(cn, ".%d", task_tgid_vnr(current));
if (err)
return err;
}
return ispipe;
}
static int zap_process(struct task_struct *start, int exit_code)
{
struct task_struct *t;
int nr = 0;
/* Allow SIGKILL, see prepare_signal() */
start->signal->flags = SIGNAL_GROUP_EXIT;
start->signal->group_exit_code = exit_code;
start->signal->group_stop_count = 0;
for_each_thread(start, t) {
task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
if (t != current && !(t->flags & PF_POSTCOREDUMP)) {
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
/* The vhost_worker does not particpate in coredumps */
if ((t->flags & (PF_USER_WORKER | PF_IO_WORKER)) != PF_USER_WORKER)
nr++;
}
}
return nr;
}
static int zap_threads(struct task_struct *tsk,
struct core_state *core_state, int exit_code)
{
struct signal_struct *signal = tsk->signal;
int nr = -EAGAIN;
spin_lock_irq(&tsk->sighand->siglock);
if (!(signal->flags & SIGNAL_GROUP_EXIT) && !signal->group_exec_task) {
signal->core_state = core_state;
nr = zap_process(tsk, exit_code);
clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
tsk->flags |= PF_DUMPCORE;
atomic_set(&core_state->nr_threads, nr);
}
spin_unlock_irq(&tsk->sighand->siglock);
return nr;
}
static int coredump_wait(int exit_code, struct core_state *core_state)
{
struct task_struct *tsk = current;
int core_waiters = -EBUSY;
init_completion(&core_state->startup);
core_state->dumper.task = tsk;
core_state->dumper.next = NULL;
core_waiters = zap_threads(tsk, core_state, exit_code);
if (core_waiters > 0) {
struct core_thread *ptr;
wait_for_completion_state(&core_state->startup,
TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
/*
* Wait for all the threads to become inactive, so that
* all the thread context (extended register state, like
* fpu etc) gets copied to the memory.
*/
ptr = core_state->dumper.next;
while (ptr != NULL) {
wait_task_inactive(ptr->task, TASK_ANY);
ptr = ptr->next;
}
}
return core_waiters;
}
static void coredump_finish(bool core_dumped)
{
struct core_thread *curr, *next;
struct task_struct *task;
spin_lock_irq(¤t->sighand->siglock);
if (core_dumped && !__fatal_signal_pending(current))
current->signal->group_exit_code |= 0x80;
next = current->signal->core_state->dumper.next;
current->signal->core_state = NULL;
spin_unlock_irq(¤t->sighand->siglock);
while ((curr = next) != NULL) {
next = curr->next;
task = curr->task;
/*
* see coredump_task_exit(), curr->task must not see
* ->task == NULL before we read ->next.
*/
smp_mb();
curr->task = NULL;
wake_up_process(task);
}
}
static bool dump_interrupted(void)
{
/*
* SIGKILL or freezing() interrupt the coredumping. Perhaps we
* can do try_to_freeze() and check __fatal_signal_pending(),
* but then we need to teach dump_write() to restart and clear
* TIF_SIGPENDING.
*/
return fatal_signal_pending(current) || freezing(current);
}
static void wait_for_dump_helpers(struct file *file)
{
struct pipe_inode_info *pipe = file->private_data;
pipe_lock(pipe);
pipe->readers++;
pipe->writers--;
wake_up_interruptible_sync(&pipe->rd_wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
pipe_unlock(pipe);
/*
* We actually want wait_event_freezable() but then we need
* to clear TIF_SIGPENDING and improve dump_interrupted().
*/
wait_event_interruptible(pipe->rd_wait, pipe->readers == 1);
pipe_lock(pipe);
pipe->readers--;
pipe->writers++;
pipe_unlock(pipe);
}
/*
* umh_pipe_setup
* helper function to customize the process used
* to collect the core in userspace. Specifically
* it sets up a pipe and installs it as fd 0 (stdin)
* for the process. Returns 0 on success, or
* PTR_ERR on failure.
* Note that it also sets the core limit to 1. This
* is a special value that we use to trap recursive
* core dumps
*/
static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
{
struct file *files[2];
struct coredump_params *cp = (struct coredump_params *)info->data;
int err = create_pipe_files(files, 0);
if (err)
return err;
cp->file = files[1];
err = replace_fd(0, files[0], 0);
fput(files[0]);
/* and disallow core files too */
current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
return err;
}
void do_coredump(const kernel_siginfo_t *siginfo)
{
struct core_state core_state;
struct core_name cn;
struct mm_struct *mm = current->mm;
struct linux_binfmt * binfmt;
const struct cred *old_cred;
struct cred *cred;
int retval = 0;
int ispipe;
size_t *argv = NULL;
int argc = 0;
/* require nonrelative corefile path and be extra careful */
bool need_suid_safe = false;
bool core_dumped = false;
static atomic_t core_dump_count = ATOMIC_INIT(0);
struct coredump_params cprm = {
.siginfo = siginfo,
.limit = rlimit(RLIMIT_CORE),
/*
* We must use the same mm->flags while dumping core to avoid
* inconsistency of bit flags, since this flag is not protected
* by any locks.
*/
.mm_flags = mm->flags,
.vma_meta = NULL,
.cpu = raw_smp_processor_id(),
};
audit_core_dumps(siginfo->si_signo);
binfmt = mm->binfmt;
if (!binfmt || !binfmt->core_dump)
goto fail;
if (!__get_dumpable(cprm.mm_flags))
goto fail;
cred = prepare_creds();
if (!cred)
goto fail;
/*
* We cannot trust fsuid as being the "true" uid of the process
* nor do we know its entire history. We only know it was tainted
* so we dump it as root in mode 2, and only into a controlled
* environment (pipe handler or fully qualified path).
*/
if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) {
/* Setuid core dump mode */
cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */
need_suid_safe = true;
}
retval = coredump_wait(siginfo->si_signo, &core_state);
if (retval < 0)
goto fail_creds;
old_cred = override_creds(cred);
ispipe = format_corename(&cn, &cprm, &argv, &argc);
if (ispipe) {
int argi;
int dump_count;
char **helper_argv;
struct subprocess_info *sub_info;
if (ispipe < 0) {
printk(KERN_WARNING "format_corename failed\n");
printk(KERN_WARNING "Aborting core\n");
goto fail_unlock;
}
if (cprm.limit == 1) {
/* See umh_pipe_setup() which sets RLIMIT_CORE = 1.
*
* Normally core limits are irrelevant to pipes, since
* we're not writing to the file system, but we use
* cprm.limit of 1 here as a special value, this is a
* consistent way to catch recursive crashes.
* We can still crash if the core_pattern binary sets
* RLIM_CORE = !1, but it runs as root, and can do
* lots of stupid things.
*
* Note that we use task_tgid_vnr here to grab the pid
* of the process group leader. That way we get the
* right pid if a thread in a multi-threaded
* core_pattern process dies.
*/
printk(KERN_WARNING
"Process %d(%s) has RLIMIT_CORE set to 1\n",
task_tgid_vnr(current), current->comm);
printk(KERN_WARNING "Aborting core\n");
goto fail_unlock;
}
cprm.limit = RLIM_INFINITY;
dump_count = atomic_inc_return(&core_dump_count);
if (core_pipe_limit && (core_pipe_limit < dump_count)) {
printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n",
task_tgid_vnr(current), current->comm);
printk(KERN_WARNING "Skipping core dump\n");
goto fail_dropcount;
}
helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv),
GFP_KERNEL);
if (!helper_argv) {
printk(KERN_WARNING "%s failed to allocate memory\n",
__func__);
goto fail_dropcount;
}
for (argi = 0; argi < argc; argi++)
helper_argv[argi] = cn.corename + argv[argi];
helper_argv[argi] = NULL;
retval = -ENOMEM;
sub_info = call_usermodehelper_setup(helper_argv[0],
helper_argv, NULL, GFP_KERNEL,
umh_pipe_setup, NULL, &cprm);
if (sub_info)
retval = call_usermodehelper_exec(sub_info,
UMH_WAIT_EXEC);
kfree(helper_argv);
if (retval) {
printk(KERN_INFO "Core dump to |%s pipe failed\n",
cn.corename);
goto close_fail;
}
} else {
struct mnt_idmap *idmap;
struct inode *inode;
int open_flags = O_CREAT | O_WRONLY | O_NOFOLLOW |
O_LARGEFILE | O_EXCL;
if (cprm.limit < binfmt->min_coredump)
goto fail_unlock;
if (need_suid_safe && cn.corename[0] != '/') {
printk(KERN_WARNING "Pid %d(%s) can only dump core "\
"to fully qualified path!\n",
task_tgid_vnr(current), current->comm);
printk(KERN_WARNING "Skipping core dump\n");
goto fail_unlock;
}
/*
* Unlink the file if it exists unless this is a SUID
* binary - in that case, we're running around with root
* privs and don't want to unlink another user's coredump.
*/
if (!need_suid_safe) {
/*
* If it doesn't exist, that's fine. If there's some
* other problem, we'll catch it at the filp_open().
*/
do_unlinkat(AT_FDCWD, getname_kernel(cn.corename));
}
/*
* There is a race between unlinking and creating the
* file, but if that causes an EEXIST here, that's
* fine - another process raced with us while creating
* the corefile, and the other process won. To userspace,
* what matters is that at least one of the two processes
* writes its coredump successfully, not which one.
*/
if (need_suid_safe) {
/*
* Using user namespaces, normal user tasks can change
* their current->fs->root to point to arbitrary
* directories. Since the intention of the "only dump
* with a fully qualified path" rule is to control where
* coredumps may be placed using root privileges,
* current->fs->root must not be used. Instead, use the
* root directory of init_task.
*/
struct path root;
task_lock(&init_task);
get_fs_root(init_task.fs, &root);
task_unlock(&init_task);
cprm.file = file_open_root(&root, cn.corename,
open_flags, 0600);
path_put(&root);
} else {
cprm.file = filp_open(cn.corename, open_flags, 0600);
}
if (IS_ERR(cprm.file))
goto fail_unlock;
inode = file_inode(cprm.file);
if (inode->i_nlink > 1)
goto close_fail;
if (d_unhashed(cprm.file->f_path.dentry))
goto close_fail;
/*
* AK: actually i see no reason to not allow this for named
* pipes etc, but keep the previous behaviour for now.
*/
if (!S_ISREG(inode->i_mode))
goto close_fail;
/*
* Don't dump core if the filesystem changed owner or mode
* of the file during file creation. This is an issue when
* a process dumps core while its cwd is e.g. on a vfat
* filesystem.
*/
idmap = file_mnt_idmap(cprm.file);
if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode),
current_fsuid())) {
pr_info_ratelimited("Core dump to %s aborted: cannot preserve file owner\n",
cn.corename);
goto close_fail;
}
if ((inode->i_mode & 0677) != 0600) {
pr_info_ratelimited("Core dump to %s aborted: cannot preserve file permissions\n",
cn.corename);
goto close_fail;
}
if (!(cprm.file->f_mode & FMODE_CAN_WRITE))
goto close_fail;
if (do_truncate(idmap, cprm.file->f_path.dentry,
0, 0, cprm.file))
goto close_fail;
}
/* get us an unshared descriptor table; almost always a no-op */
/* The cell spufs coredump code reads the file descriptor tables */
retval = unshare_files();
if (retval)
goto close_fail;
if (!dump_interrupted()) {
/*
* umh disabled with CONFIG_STATIC_USERMODEHELPER_PATH="" would
* have this set to NULL.
*/
if (!cprm.file) {
pr_info("Core dump to |%s disabled\n", cn.corename);
goto close_fail;
}
if (!dump_vma_snapshot(&cprm))
goto close_fail;
file_start_write(cprm.file);
core_dumped = binfmt->core_dump(&cprm);
/*
* Ensures that file size is big enough to contain the current
* file postion. This prevents gdb from complaining about
* a truncated file if the last "write" to the file was
* dump_skip.
*/
if (cprm.to_skip) {
cprm.to_skip--;
dump_emit(&cprm, "", 1);
}
file_end_write(cprm.file);
free_vma_snapshot(&cprm);
}
if (ispipe && core_pipe_limit)
wait_for_dump_helpers(cprm.file);
close_fail:
if (cprm.file)
filp_close(cprm.file, NULL);
fail_dropcount:
if (ispipe)
atomic_dec(&core_dump_count);
fail_unlock:
kfree(argv);
kfree(cn.corename);
coredump_finish(core_dumped);
revert_creds(old_cred);
fail_creds:
put_cred(cred);
fail:
return;
}
/*
* Core dumping helper functions. These are the only things you should
* do on a core-file: use only these functions to write out all the
* necessary info.
*/
static int __dump_emit(struct coredump_params *cprm, const void *addr, int nr)
{
struct file *file = cprm->file;
loff_t pos = file->f_pos;
ssize_t n;
if (cprm->written + nr > cprm->limit)
return 0;
if (dump_interrupted())
return 0;
n = __kernel_write(file, addr, nr, &pos);
if (n != nr)
return 0;
file->f_pos = pos;
cprm->written += n;
cprm->pos += n;
return 1;
}
static int __dump_skip(struct coredump_params *cprm, size_t nr)
{
static char zeroes[PAGE_SIZE];
struct file *file = cprm->file;
if (file->f_mode & FMODE_LSEEK) {
if (dump_interrupted() ||
vfs_llseek(file, nr, SEEK_CUR) < 0)
return 0;
cprm->pos += nr;
return 1;
} else {
while (nr > PAGE_SIZE) {
if (!__dump_emit(cprm, zeroes, PAGE_SIZE))
return 0;
nr -= PAGE_SIZE;
}
return __dump_emit(cprm, zeroes, nr);
}
}
int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
{
if (cprm->to_skip) {
if (!__dump_skip(cprm, cprm->to_skip))
return 0;
cprm->to_skip = 0;
}
return __dump_emit(cprm, addr, nr);
}
EXPORT_SYMBOL(dump_emit);
void dump_skip_to(struct coredump_params *cprm, unsigned long pos)
{
cprm->to_skip = pos - cprm->pos;
}
EXPORT_SYMBOL(dump_skip_to);
void dump_skip(struct coredump_params *cprm, size_t nr)
{
cprm->to_skip += nr;
}
EXPORT_SYMBOL(dump_skip);
#ifdef CONFIG_ELF_CORE
static int dump_emit_page(struct coredump_params *cprm, struct page *page)
{
struct bio_vec bvec;
struct iov_iter iter;
struct file *file = cprm->file;
loff_t pos;
ssize_t n;
if (cprm->to_skip) {
if (!__dump_skip(cprm, cprm->to_skip))
return 0;
cprm->to_skip = 0;
}
if (cprm->written + PAGE_SIZE > cprm->limit)
return 0;
if (dump_interrupted())
return 0;
pos = file->f_pos;
bvec_set_page(&bvec, page, PAGE_SIZE, 0);
iov_iter_bvec(&iter, ITER_SOURCE, &bvec, 1, PAGE_SIZE);
iov_iter_set_copy_mc(&iter);
n = __kernel_write_iter(cprm->file, &iter, &pos);
if (n != PAGE_SIZE)
return 0;
file->f_pos = pos;
cprm->written += PAGE_SIZE;
cprm->pos += PAGE_SIZE;
return 1;
}
int dump_user_range(struct coredump_params *cprm, unsigned long start,
unsigned long len)
{
unsigned long addr;
for (addr = start; addr < start + len; addr += PAGE_SIZE) {
struct page *page;
/*
* To avoid having to allocate page tables for virtual address
* ranges that have never been used yet, and also to make it
* easy to generate sparse core files, use a helper that returns
* NULL when encountering an empty page table entry that would
* otherwise have been filled with the zero page.
*/
page = get_dump_page(addr);
if (page) {
int stop = !dump_emit_page(cprm, page);
put_page(page);
if (stop)
return 0;
} else {
dump_skip(cprm, PAGE_SIZE);
}
}
return 1;
}
#endif
int dump_align(struct coredump_params *cprm, int align)
{
unsigned mod = (cprm->pos + cprm->to_skip) & (align - 1);
if (align & (align - 1))
return 0;
if (mod)
cprm->to_skip += align - mod;
return 1;
}
EXPORT_SYMBOL(dump_align);
#ifdef CONFIG_SYSCTL
void validate_coredump_safety(void)
{
if (suid_dumpable == SUID_DUMP_ROOT &&
core_pattern[0] != '/' && core_pattern[0] != '|') {
pr_warn(
"Unsafe core_pattern used with fs.suid_dumpable=2.\n"
"Pipe handler or fully qualified core dump path required.\n"
"Set kernel.core_pattern before fs.suid_dumpable.\n"
);
}
}
static int proc_dostring_coredump(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int error = proc_dostring(table, write, buffer, lenp, ppos);
if (!error)
validate_coredump_safety();
return error;
}
static struct ctl_table coredump_sysctls[] = {
{
.procname = "core_uses_pid",
.data = &core_uses_pid,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "core_pattern",
.data = core_pattern,
.maxlen = CORENAME_MAX_SIZE,
.mode = 0644,
.proc_handler = proc_dostring_coredump,
},
{
.procname = "core_pipe_limit",
.data = &core_pipe_limit,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static int __init init_fs_coredump_sysctls(void)
{
register_sysctl_init("kernel", coredump_sysctls);
return 0;
}
fs_initcall(init_fs_coredump_sysctls);
#endif /* CONFIG_SYSCTL */
/*
* The purpose of always_dump_vma() is to make sure that special kernel mappings
* that are useful for post-mortem analysis are included in every core dump.
* In that way we ensure that the core dump is fully interpretable later
* without matching up the same kernel and hardware config to see what PC values
* meant. These special mappings include - vDSO, vsyscall, and other
* architecture specific mappings
*/
static bool always_dump_vma(struct vm_area_struct *vma)
{
/* Any vsyscall mappings? */
if (vma == get_gate_vma(vma->vm_mm))
return true;
/*
* Assume that all vmas with a .name op should always be dumped.
* If this changes, a new vm_ops field can easily be added.
*/
if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
return true;
/*
* arch_vma_name() returns non-NULL for special architecture mappings,
* such as vDSO sections.
*/
if (arch_vma_name(vma))
return true;
return false;
}
#define DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER 1
/*
* Decide how much of @vma's contents should be included in a core dump.
*/
static unsigned long vma_dump_size(struct vm_area_struct *vma,
unsigned long mm_flags)
{
#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
/* always dump the vdso and vsyscall sections */
if (always_dump_vma(vma))
goto whole;
if (vma->vm_flags & VM_DONTDUMP)
return 0;
/* support for DAX */
if (vma_is_dax(vma)) {
if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED))
goto whole;
if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE))
goto whole;
return 0;
}
/* Hugetlb memory check */
if (is_vm_hugetlb_page(vma)) {
if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
goto whole;
if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
goto whole;
return 0;
}
/* Do not dump I/O mapped devices or special mappings */
if (vma->vm_flags & VM_IO)
return 0;
/* By default, dump shared memory if mapped from an anonymous file. */
if (vma->vm_flags & VM_SHARED) {
if (file_inode(vma->vm_file)->i_nlink == 0 ?
FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
goto whole;
return 0;
}
/* Dump segments that have been written to. */
if ((!IS_ENABLED(CONFIG_MMU) || vma->anon_vma) && FILTER(ANON_PRIVATE))
goto whole;
if (vma->vm_file == NULL)
return 0;
if (FILTER(MAPPED_PRIVATE))
goto whole;
/*
* If this is the beginning of an executable file mapping,
* dump the first page to aid in determining what was mapped here.
*/
if (FILTER(ELF_HEADERS) &&
vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
if ((READ_ONCE(file_inode(vma->vm_file)->i_mode) & 0111) != 0)
return PAGE_SIZE;
/*
* ELF libraries aren't always executable.
* We'll want to check whether the mapping starts with the ELF
* magic, but not now - we're holding the mmap lock,
* so copy_from_user() doesn't work here.
* Use a placeholder instead, and fix it up later in
* dump_vma_snapshot().
*/
return DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER;
}
#undef FILTER
return 0;
whole:
return vma->vm_end - vma->vm_start;
}
/*
* Helper function for iterating across a vma list. It ensures that the caller
* will visit `gate_vma' prior to terminating the search.
*/
static struct vm_area_struct *coredump_next_vma(struct vma_iterator *vmi,
struct vm_area_struct *vma,
struct vm_area_struct *gate_vma)
{
if (gate_vma && (vma == gate_vma))
return NULL;
vma = vma_next(vmi);
if (vma)
return vma;
return gate_vma;
}
static void free_vma_snapshot(struct coredump_params *cprm)
{
if (cprm->vma_meta) {
int i;
for (i = 0; i < cprm->vma_count; i++) {
struct file *file = cprm->vma_meta[i].file;
if (file)
fput(file);
}
kvfree(cprm->vma_meta);
cprm->vma_meta = NULL;
}
}
/*
* Under the mmap_lock, take a snapshot of relevant information about the task's
* VMAs.
*/
static bool dump_vma_snapshot(struct coredump_params *cprm)
{
struct vm_area_struct *gate_vma, *vma = NULL;
struct mm_struct *mm = current->mm;
VMA_ITERATOR(vmi, mm, 0);
int i = 0;
/*
* Once the stack expansion code is fixed to not change VMA bounds
* under mmap_lock in read mode, this can be changed to take the
* mmap_lock in read mode.
*/
if (mmap_write_lock_killable(mm))
return false;
cprm->vma_data_size = 0;
gate_vma = get_gate_vma(mm);
cprm->vma_count = mm->map_count + (gate_vma ? 1 : 0);
cprm->vma_meta = kvmalloc_array(cprm->vma_count, sizeof(*cprm->vma_meta), GFP_KERNEL);
if (!cprm->vma_meta) {
mmap_write_unlock(mm);
return false;
}
while ((vma = coredump_next_vma(&vmi, vma, gate_vma)) != NULL) {
struct core_vma_metadata *m = cprm->vma_meta + i;
m->start = vma->vm_start;
m->end = vma->vm_end;
m->flags = vma->vm_flags;
m->dump_size = vma_dump_size(vma, cprm->mm_flags);
m->pgoff = vma->vm_pgoff;
m->file = vma->vm_file;
if (m->file)
get_file(m->file);
i++;
}
mmap_write_unlock(mm);
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *m = cprm->vma_meta + i;
if (m->dump_size == DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER) {
char elfmag[SELFMAG];
if (copy_from_user(elfmag, (void __user *)m->start, SELFMAG) ||
memcmp(elfmag, ELFMAG, SELFMAG) != 0) {
m->dump_size = 0;
} else {
m->dump_size = PAGE_SIZE;
}
}
cprm->vma_data_size += m->dump_size;
}
return true;
}
| linux-master | fs/coredump.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Routines that mimic syscalls, but don't use the user address space or file
* descriptors. Only for init/ and related early init code.
*/
#include <linux/init.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/fs.h>
#include <linux/fs_struct.h>
#include <linux/file.h>
#include <linux/init_syscalls.h>
#include <linux/security.h>
#include "internal.h"
int __init init_mount(const char *dev_name, const char *dir_name,
const char *type_page, unsigned long flags, void *data_page)
{
struct path path;
int ret;
ret = kern_path(dir_name, LOOKUP_FOLLOW, &path);
if (ret)
return ret;
ret = path_mount(dev_name, &path, type_page, flags, data_page);
path_put(&path);
return ret;
}
int __init init_umount(const char *name, int flags)
{
int lookup_flags = LOOKUP_MOUNTPOINT;
struct path path;
int ret;
if (!(flags & UMOUNT_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
ret = kern_path(name, lookup_flags, &path);
if (ret)
return ret;
return path_umount(&path, flags);
}
int __init init_chdir(const char *filename)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (error)
return error;
error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (!error)
set_fs_pwd(current->fs, &path);
path_put(&path);
return error;
}
int __init init_chroot(const char *filename)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (error)
return error;
error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (error)
goto dput_and_out;
error = -EPERM;
if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
goto dput_and_out;
error = security_path_chroot(&path);
if (error)
goto dput_and_out;
set_fs_root(current->fs, &path);
dput_and_out:
path_put(&path);
return error;
}
int __init init_chown(const char *filename, uid_t user, gid_t group, int flags)
{
int lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
struct path path;
int error;
error = kern_path(filename, lookup_flags, &path);
if (error)
return error;
error = mnt_want_write(path.mnt);
if (!error) {
error = chown_common(&path, user, group);
mnt_drop_write(path.mnt);
}
path_put(&path);
return error;
}
int __init init_chmod(const char *filename, umode_t mode)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW, &path);
if (error)
return error;
error = chmod_common(&path, mode);
path_put(&path);
return error;
}
int __init init_eaccess(const char *filename)
{
struct path path;
int error;
error = kern_path(filename, LOOKUP_FOLLOW, &path);
if (error)
return error;
error = path_permission(&path, MAY_ACCESS);
path_put(&path);
return error;
}
int __init init_stat(const char *filename, struct kstat *stat, int flags)
{
int lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
struct path path;
int error;
error = kern_path(filename, lookup_flags, &path);
if (error)
return error;
error = vfs_getattr(&path, stat, STATX_BASIC_STATS,
flags | AT_NO_AUTOMOUNT);
path_put(&path);
return error;
}
int __init init_mknod(const char *filename, umode_t mode, unsigned int dev)
{
struct dentry *dentry;
struct path path;
int error;
if (S_ISFIFO(mode) || S_ISSOCK(mode))
dev = 0;
else if (!(S_ISBLK(mode) || S_ISCHR(mode)))
return -EINVAL;
dentry = kern_path_create(AT_FDCWD, filename, &path, 0);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mknod(&path, dentry, mode, dev);
if (!error)
error = vfs_mknod(mnt_idmap(path.mnt), path.dentry->d_inode,
dentry, mode, new_decode_dev(dev));
done_path_create(&path, dentry);
return error;
}
int __init init_link(const char *oldname, const char *newname)
{
struct dentry *new_dentry;
struct path old_path, new_path;
struct mnt_idmap *idmap;
int error;
error = kern_path(oldname, 0, &old_path);
if (error)
return error;
new_dentry = kern_path_create(AT_FDCWD, newname, &new_path, 0);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto out;
error = -EXDEV;
if (old_path.mnt != new_path.mnt)
goto out_dput;
idmap = mnt_idmap(new_path.mnt);
error = may_linkat(idmap, &old_path);
if (unlikely(error))
goto out_dput;
error = security_path_link(old_path.dentry, &new_path, new_dentry);
if (error)
goto out_dput;
error = vfs_link(old_path.dentry, idmap, new_path.dentry->d_inode,
new_dentry, NULL);
out_dput:
done_path_create(&new_path, new_dentry);
out:
path_put(&old_path);
return error;
}
int __init init_symlink(const char *oldname, const char *newname)
{
struct dentry *dentry;
struct path path;
int error;
dentry = kern_path_create(AT_FDCWD, newname, &path, 0);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
error = security_path_symlink(&path, dentry, oldname);
if (!error)
error = vfs_symlink(mnt_idmap(path.mnt), path.dentry->d_inode,
dentry, oldname);
done_path_create(&path, dentry);
return error;
}
int __init init_unlink(const char *pathname)
{
return do_unlinkat(AT_FDCWD, getname_kernel(pathname));
}
int __init init_mkdir(const char *pathname, umode_t mode)
{
struct dentry *dentry;
struct path path;
int error;
dentry = kern_path_create(AT_FDCWD, pathname, &path, LOOKUP_DIRECTORY);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mkdir(&path, dentry, mode);
if (!error)
error = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode,
dentry, mode);
done_path_create(&path, dentry);
return error;
}
int __init init_rmdir(const char *pathname)
{
return do_rmdir(AT_FDCWD, getname_kernel(pathname));
}
int __init init_utimes(char *filename, struct timespec64 *ts)
{
struct path path;
int error;
error = kern_path(filename, 0, &path);
if (error)
return error;
error = vfs_utimes(&path, ts);
path_put(&path);
return error;
}
int __init init_dup(struct file *file)
{
int fd;
fd = get_unused_fd_flags(0);
if (fd < 0)
return fd;
fd_install(fd, get_file(file));
return 0;
}
| linux-master | fs/init.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/seq_file.c
*
* helper functions for making synthetic files from sequences of records.
* initial implementation -- AV, Oct 2001.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cache.h>
#include <linux/fs.h>
#include <linux/export.h>
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/mm.h>
#include <linux/printk.h>
#include <linux/string_helpers.h>
#include <linux/uio.h>
#include <linux/uaccess.h>
#include <asm/page.h>
static struct kmem_cache *seq_file_cache __ro_after_init;
static void seq_set_overflow(struct seq_file *m)
{
m->count = m->size;
}
static void *seq_buf_alloc(unsigned long size)
{
if (unlikely(size > MAX_RW_COUNT))
return NULL;
return kvmalloc(size, GFP_KERNEL_ACCOUNT);
}
/**
* seq_open - initialize sequential file
* @file: file we initialize
* @op: method table describing the sequence
*
* seq_open() sets @file, associating it with a sequence described
* by @op. @op->start() sets the iterator up and returns the first
* element of sequence. @op->stop() shuts it down. @op->next()
* returns the next element of sequence. @op->show() prints element
* into the buffer. In case of error ->start() and ->next() return
* ERR_PTR(error). In the end of sequence they return %NULL. ->show()
* returns 0 in case of success and negative number in case of error.
* Returning SEQ_SKIP means "discard this element and move on".
* Note: seq_open() will allocate a struct seq_file and store its
* pointer in @file->private_data. This pointer should not be modified.
*/
int seq_open(struct file *file, const struct seq_operations *op)
{
struct seq_file *p;
WARN_ON(file->private_data);
p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);
if (!p)
return -ENOMEM;
file->private_data = p;
mutex_init(&p->lock);
p->op = op;
// No refcounting: the lifetime of 'p' is constrained
// to the lifetime of the file.
p->file = file;
/*
* seq_files support lseek() and pread(). They do not implement
* write() at all, but we clear FMODE_PWRITE here for historical
* reasons.
*
* If a client of seq_files a) implements file.write() and b) wishes to
* support pwrite() then that client will need to implement its own
* file.open() which calls seq_open() and then sets FMODE_PWRITE.
*/
file->f_mode &= ~FMODE_PWRITE;
return 0;
}
EXPORT_SYMBOL(seq_open);
static int traverse(struct seq_file *m, loff_t offset)
{
loff_t pos = 0;
int error = 0;
void *p;
m->index = 0;
m->count = m->from = 0;
if (!offset)
return 0;
if (!m->buf) {
m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
if (!m->buf)
return -ENOMEM;
}
p = m->op->start(m, &m->index);
while (p) {
error = PTR_ERR(p);
if (IS_ERR(p))
break;
error = m->op->show(m, p);
if (error < 0)
break;
if (unlikely(error)) {
error = 0;
m->count = 0;
}
if (seq_has_overflowed(m))
goto Eoverflow;
p = m->op->next(m, p, &m->index);
if (pos + m->count > offset) {
m->from = offset - pos;
m->count -= m->from;
break;
}
pos += m->count;
m->count = 0;
if (pos == offset)
break;
}
m->op->stop(m, p);
return error;
Eoverflow:
m->op->stop(m, p);
kvfree(m->buf);
m->count = 0;
m->buf = seq_buf_alloc(m->size <<= 1);
return !m->buf ? -ENOMEM : -EAGAIN;
}
/**
* seq_read - ->read() method for sequential files.
* @file: the file to read from
* @buf: the buffer to read to
* @size: the maximum number of bytes to read
* @ppos: the current position in the file
*
* Ready-made ->f_op->read()
*/
ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
struct iovec iov = { .iov_base = buf, .iov_len = size};
struct kiocb kiocb;
struct iov_iter iter;
ssize_t ret;
init_sync_kiocb(&kiocb, file);
iov_iter_init(&iter, ITER_DEST, &iov, 1, size);
kiocb.ki_pos = *ppos;
ret = seq_read_iter(&kiocb, &iter);
*ppos = kiocb.ki_pos;
return ret;
}
EXPORT_SYMBOL(seq_read);
/*
* Ready-made ->f_op->read_iter()
*/
ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct seq_file *m = iocb->ki_filp->private_data;
size_t copied = 0;
size_t n;
void *p;
int err = 0;
if (!iov_iter_count(iter))
return 0;
mutex_lock(&m->lock);
/*
* if request is to read from zero offset, reset iterator to first
* record as it might have been already advanced by previous requests
*/
if (iocb->ki_pos == 0) {
m->index = 0;
m->count = 0;
}
/* Don't assume ki_pos is where we left it */
if (unlikely(iocb->ki_pos != m->read_pos)) {
while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN)
;
if (err) {
/* With prejudice... */
m->read_pos = 0;
m->index = 0;
m->count = 0;
goto Done;
} else {
m->read_pos = iocb->ki_pos;
}
}
/* grab buffer if we didn't have one */
if (!m->buf) {
m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
if (!m->buf)
goto Enomem;
}
// something left in the buffer - copy it out first
if (m->count) {
n = copy_to_iter(m->buf + m->from, m->count, iter);
m->count -= n;
m->from += n;
copied += n;
if (m->count) // hadn't managed to copy everything
goto Done;
}
// get a non-empty record in the buffer
m->from = 0;
p = m->op->start(m, &m->index);
while (1) {
err = PTR_ERR(p);
if (!p || IS_ERR(p)) // EOF or an error
break;
err = m->op->show(m, p);
if (err < 0) // hard error
break;
if (unlikely(err)) // ->show() says "skip it"
m->count = 0;
if (unlikely(!m->count)) { // empty record
p = m->op->next(m, p, &m->index);
continue;
}
if (!seq_has_overflowed(m)) // got it
goto Fill;
// need a bigger buffer
m->op->stop(m, p);
kvfree(m->buf);
m->count = 0;
m->buf = seq_buf_alloc(m->size <<= 1);
if (!m->buf)
goto Enomem;
p = m->op->start(m, &m->index);
}
// EOF or an error
m->op->stop(m, p);
m->count = 0;
goto Done;
Fill:
// one non-empty record is in the buffer; if they want more,
// try to fit more in, but in any case we need to advance
// the iterator once for every record shown.
while (1) {
size_t offs = m->count;
loff_t pos = m->index;
p = m->op->next(m, p, &m->index);
if (pos == m->index) {
pr_info_ratelimited("buggy .next function %ps did not update position index\n",
m->op->next);
m->index++;
}
if (!p || IS_ERR(p)) // no next record for us
break;
if (m->count >= iov_iter_count(iter))
break;
err = m->op->show(m, p);
if (err > 0) { // ->show() says "skip it"
m->count = offs;
} else if (err || seq_has_overflowed(m)) {
m->count = offs;
break;
}
}
m->op->stop(m, p);
n = copy_to_iter(m->buf, m->count, iter);
copied += n;
m->count -= n;
m->from = n;
Done:
if (unlikely(!copied)) {
copied = m->count ? -EFAULT : err;
} else {
iocb->ki_pos += copied;
m->read_pos += copied;
}
mutex_unlock(&m->lock);
return copied;
Enomem:
err = -ENOMEM;
goto Done;
}
EXPORT_SYMBOL(seq_read_iter);
/**
* seq_lseek - ->llseek() method for sequential files.
* @file: the file in question
* @offset: new position
* @whence: 0 for absolute, 1 for relative position
*
* Ready-made ->f_op->llseek()
*/
loff_t seq_lseek(struct file *file, loff_t offset, int whence)
{
struct seq_file *m = file->private_data;
loff_t retval = -EINVAL;
mutex_lock(&m->lock);
switch (whence) {
case SEEK_CUR:
offset += file->f_pos;
fallthrough;
case SEEK_SET:
if (offset < 0)
break;
retval = offset;
if (offset != m->read_pos) {
while ((retval = traverse(m, offset)) == -EAGAIN)
;
if (retval) {
/* with extreme prejudice... */
file->f_pos = 0;
m->read_pos = 0;
m->index = 0;
m->count = 0;
} else {
m->read_pos = offset;
retval = file->f_pos = offset;
}
} else {
file->f_pos = offset;
}
}
mutex_unlock(&m->lock);
return retval;
}
EXPORT_SYMBOL(seq_lseek);
/**
* seq_release - free the structures associated with sequential file.
* @file: file in question
* @inode: its inode
*
* Frees the structures associated with sequential file; can be used
* as ->f_op->release() if you don't have private data to destroy.
*/
int seq_release(struct inode *inode, struct file *file)
{
struct seq_file *m = file->private_data;
kvfree(m->buf);
kmem_cache_free(seq_file_cache, m);
return 0;
}
EXPORT_SYMBOL(seq_release);
/**
* seq_escape_mem - print data into buffer, escaping some characters
* @m: target buffer
* @src: source buffer
* @len: size of source buffer
* @flags: flags to pass to string_escape_mem()
* @esc: set of characters that need escaping
*
* Puts data into buffer, replacing each occurrence of character from
* given class (defined by @flags and @esc) with printable escaped sequence.
*
* Use seq_has_overflowed() to check for errors.
*/
void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
unsigned int flags, const char *esc)
{
char *buf;
size_t size = seq_get_buf(m, &buf);
int ret;
ret = string_escape_mem(src, len, buf, size, flags, esc);
seq_commit(m, ret < size ? ret : -1);
}
EXPORT_SYMBOL(seq_escape_mem);
void seq_vprintf(struct seq_file *m, const char *f, va_list args)
{
int len;
if (m->count < m->size) {
len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
if (m->count + len < m->size) {
m->count += len;
return;
}
}
seq_set_overflow(m);
}
EXPORT_SYMBOL(seq_vprintf);
void seq_printf(struct seq_file *m, const char *f, ...)
{
va_list args;
va_start(args, f);
seq_vprintf(m, f, args);
va_end(args);
}
EXPORT_SYMBOL(seq_printf);
#ifdef CONFIG_BINARY_PRINTF
void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary)
{
int len;
if (m->count < m->size) {
len = bstr_printf(m->buf + m->count, m->size - m->count, f,
binary);
if (m->count + len < m->size) {
m->count += len;
return;
}
}
seq_set_overflow(m);
}
EXPORT_SYMBOL(seq_bprintf);
#endif /* CONFIG_BINARY_PRINTF */
/**
* mangle_path - mangle and copy path to buffer beginning
* @s: buffer start
* @p: beginning of path in above buffer
* @esc: set of characters that need escaping
*
* Copy the path from @p to @s, replacing each occurrence of character from
* @esc with usual octal escape.
* Returns pointer past last written character in @s, or NULL in case of
* failure.
*/
char *mangle_path(char *s, const char *p, const char *esc)
{
while (s <= p) {
char c = *p++;
if (!c) {
return s;
} else if (!strchr(esc, c)) {
*s++ = c;
} else if (s + 4 > p) {
break;
} else {
*s++ = '\\';
*s++ = '0' + ((c & 0300) >> 6);
*s++ = '0' + ((c & 070) >> 3);
*s++ = '0' + (c & 07);
}
}
return NULL;
}
EXPORT_SYMBOL(mangle_path);
/**
* seq_path - seq_file interface to print a pathname
* @m: the seq_file handle
* @path: the struct path to print
* @esc: set of characters to escape in the output
*
* return the absolute path of 'path', as represented by the
* dentry / mnt pair in the path parameter.
*/
int seq_path(struct seq_file *m, const struct path *path, const char *esc)
{
char *buf;
size_t size = seq_get_buf(m, &buf);
int res = -1;
if (size) {
char *p = d_path(path, buf, size);
if (!IS_ERR(p)) {
char *end = mangle_path(buf, p, esc);
if (end)
res = end - buf;
}
}
seq_commit(m, res);
return res;
}
EXPORT_SYMBOL(seq_path);
/**
* seq_file_path - seq_file interface to print a pathname of a file
* @m: the seq_file handle
* @file: the struct file to print
* @esc: set of characters to escape in the output
*
* return the absolute path to the file.
*/
int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
{
return seq_path(m, &file->f_path, esc);
}
EXPORT_SYMBOL(seq_file_path);
/*
* Same as seq_path, but relative to supplied root.
*/
int seq_path_root(struct seq_file *m, const struct path *path,
const struct path *root, const char *esc)
{
char *buf;
size_t size = seq_get_buf(m, &buf);
int res = -ENAMETOOLONG;
if (size) {
char *p;
p = __d_path(path, root, buf, size);
if (!p)
return SEQ_SKIP;
res = PTR_ERR(p);
if (!IS_ERR(p)) {
char *end = mangle_path(buf, p, esc);
if (end)
res = end - buf;
else
res = -ENAMETOOLONG;
}
}
seq_commit(m, res);
return res < 0 && res != -ENAMETOOLONG ? res : 0;
}
/*
* returns the path of the 'dentry' from the root of its filesystem.
*/
int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
{
char *buf;
size_t size = seq_get_buf(m, &buf);
int res = -1;
if (size) {
char *p = dentry_path(dentry, buf, size);
if (!IS_ERR(p)) {
char *end = mangle_path(buf, p, esc);
if (end)
res = end - buf;
}
}
seq_commit(m, res);
return res;
}
EXPORT_SYMBOL(seq_dentry);
void *single_start(struct seq_file *p, loff_t *pos)
{
return *pos ? NULL : SEQ_START_TOKEN;
}
static void *single_next(struct seq_file *p, void *v, loff_t *pos)
{
++*pos;
return NULL;
}
static void single_stop(struct seq_file *p, void *v)
{
}
int single_open(struct file *file, int (*show)(struct seq_file *, void *),
void *data)
{
struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL_ACCOUNT);
int res = -ENOMEM;
if (op) {
op->start = single_start;
op->next = single_next;
op->stop = single_stop;
op->show = show;
res = seq_open(file, op);
if (!res)
((struct seq_file *)file->private_data)->private = data;
else
kfree(op);
}
return res;
}
EXPORT_SYMBOL(single_open);
int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
void *data, size_t size)
{
char *buf = seq_buf_alloc(size);
int ret;
if (!buf)
return -ENOMEM;
ret = single_open(file, show, data);
if (ret) {
kvfree(buf);
return ret;
}
((struct seq_file *)file->private_data)->buf = buf;
((struct seq_file *)file->private_data)->size = size;
return 0;
}
EXPORT_SYMBOL(single_open_size);
int single_release(struct inode *inode, struct file *file)
{
const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
int res = seq_release(inode, file);
kfree(op);
return res;
}
EXPORT_SYMBOL(single_release);
int seq_release_private(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
kfree(seq->private);
seq->private = NULL;
return seq_release(inode, file);
}
EXPORT_SYMBOL(seq_release_private);
void *__seq_open_private(struct file *f, const struct seq_operations *ops,
int psize)
{
int rc;
void *private;
struct seq_file *seq;
private = kzalloc(psize, GFP_KERNEL_ACCOUNT);
if (private == NULL)
goto out;
rc = seq_open(f, ops);
if (rc < 0)
goto out_free;
seq = f->private_data;
seq->private = private;
return private;
out_free:
kfree(private);
out:
return NULL;
}
EXPORT_SYMBOL(__seq_open_private);
int seq_open_private(struct file *filp, const struct seq_operations *ops,
int psize)
{
return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
}
EXPORT_SYMBOL(seq_open_private);
void seq_putc(struct seq_file *m, char c)
{
if (m->count >= m->size)
return;
m->buf[m->count++] = c;
}
EXPORT_SYMBOL(seq_putc);
void seq_puts(struct seq_file *m, const char *s)
{
int len = strlen(s);
if (m->count + len >= m->size) {
seq_set_overflow(m);
return;
}
memcpy(m->buf + m->count, s, len);
m->count += len;
}
EXPORT_SYMBOL(seq_puts);
/**
* seq_put_decimal_ull_width - A helper routine for putting decimal numbers
* without rich format of printf().
* only 'unsigned long long' is supported.
* @m: seq_file identifying the buffer to which data should be written
* @delimiter: a string which is printed before the number
* @num: the number
* @width: a minimum field width
*
* This routine will put strlen(delimiter) + number into seq_filed.
* This routine is very quick when you show lots of numbers.
* In usual cases, it will be better to use seq_printf(). It's easier to read.
*/
void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
unsigned long long num, unsigned int width)
{
int len;
if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
goto overflow;
if (delimiter && delimiter[0]) {
if (delimiter[1] == 0)
seq_putc(m, delimiter[0]);
else
seq_puts(m, delimiter);
}
if (!width)
width = 1;
if (m->count + width >= m->size)
goto overflow;
len = num_to_str(m->buf + m->count, m->size - m->count, num, width);
if (!len)
goto overflow;
m->count += len;
return;
overflow:
seq_set_overflow(m);
}
void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
unsigned long long num)
{
return seq_put_decimal_ull_width(m, delimiter, num, 0);
}
EXPORT_SYMBOL(seq_put_decimal_ull);
/**
* seq_put_hex_ll - put a number in hexadecimal notation
* @m: seq_file identifying the buffer to which data should be written
* @delimiter: a string which is printed before the number
* @v: the number
* @width: a minimum field width
*
* seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v)
*
* This routine is very quick when you show lots of numbers.
* In usual cases, it will be better to use seq_printf(). It's easier to read.
*/
void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
unsigned long long v, unsigned int width)
{
unsigned int len;
int i;
if (delimiter && delimiter[0]) {
if (delimiter[1] == 0)
seq_putc(m, delimiter[0]);
else
seq_puts(m, delimiter);
}
/* If x is 0, the result of __builtin_clzll is undefined */
if (v == 0)
len = 1;
else
len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;
if (len < width)
len = width;
if (m->count + len > m->size) {
seq_set_overflow(m);
return;
}
for (i = len - 1; i >= 0; i--) {
m->buf[m->count + i] = hex_asc[0xf & v];
v = v >> 4;
}
m->count += len;
}
void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
{
int len;
if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */
goto overflow;
if (delimiter && delimiter[0]) {
if (delimiter[1] == 0)
seq_putc(m, delimiter[0]);
else
seq_puts(m, delimiter);
}
if (m->count + 2 >= m->size)
goto overflow;
if (num < 0) {
m->buf[m->count++] = '-';
num = -num;
}
if (num < 10) {
m->buf[m->count++] = num + '0';
return;
}
len = num_to_str(m->buf + m->count, m->size - m->count, num, 0);
if (!len)
goto overflow;
m->count += len;
return;
overflow:
seq_set_overflow(m);
}
EXPORT_SYMBOL(seq_put_decimal_ll);
/**
* seq_write - write arbitrary data to buffer
* @seq: seq_file identifying the buffer to which data should be written
* @data: data address
* @len: number of bytes
*
* Return 0 on success, non-zero otherwise.
*/
int seq_write(struct seq_file *seq, const void *data, size_t len)
{
if (seq->count + len < seq->size) {
memcpy(seq->buf + seq->count, data, len);
seq->count += len;
return 0;
}
seq_set_overflow(seq);
return -1;
}
EXPORT_SYMBOL(seq_write);
/**
* seq_pad - write padding spaces to buffer
* @m: seq_file identifying the buffer to which data should be written
* @c: the byte to append after padding if non-zero
*/
void seq_pad(struct seq_file *m, char c)
{
int size = m->pad_until - m->count;
if (size > 0) {
if (size + m->count > m->size) {
seq_set_overflow(m);
return;
}
memset(m->buf + m->count, ' ', size);
m->count += size;
}
if (c)
seq_putc(m, c);
}
EXPORT_SYMBOL(seq_pad);
/* A complete analogue of print_hex_dump() */
void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
int rowsize, int groupsize, const void *buf, size_t len,
bool ascii)
{
const u8 *ptr = buf;
int i, linelen, remaining = len;
char *buffer;
size_t size;
int ret;
if (rowsize != 16 && rowsize != 32)
rowsize = 16;
for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
linelen = min(remaining, rowsize);
remaining -= rowsize;
switch (prefix_type) {
case DUMP_PREFIX_ADDRESS:
seq_printf(m, "%s%p: ", prefix_str, ptr + i);
break;
case DUMP_PREFIX_OFFSET:
seq_printf(m, "%s%.8x: ", prefix_str, i);
break;
default:
seq_printf(m, "%s", prefix_str);
break;
}
size = seq_get_buf(m, &buffer);
ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
buffer, size, ascii);
seq_commit(m, ret < size ? ret : -1);
seq_putc(m, '\n');
}
}
EXPORT_SYMBOL(seq_hex_dump);
struct list_head *seq_list_start(struct list_head *head, loff_t pos)
{
struct list_head *lh;
list_for_each(lh, head)
if (pos-- == 0)
return lh;
return NULL;
}
EXPORT_SYMBOL(seq_list_start);
struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
{
if (!pos)
return head;
return seq_list_start(head, pos - 1);
}
EXPORT_SYMBOL(seq_list_start_head);
struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
{
struct list_head *lh;
lh = ((struct list_head *)v)->next;
++*ppos;
return lh == head ? NULL : lh;
}
EXPORT_SYMBOL(seq_list_next);
struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos)
{
struct list_head *lh;
list_for_each_rcu(lh, head)
if (pos-- == 0)
return lh;
return NULL;
}
EXPORT_SYMBOL(seq_list_start_rcu);
struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos)
{
if (!pos)
return head;
return seq_list_start_rcu(head, pos - 1);
}
EXPORT_SYMBOL(seq_list_start_head_rcu);
struct list_head *seq_list_next_rcu(void *v, struct list_head *head,
loff_t *ppos)
{
struct list_head *lh;
lh = list_next_rcu((struct list_head *)v);
++*ppos;
return lh == head ? NULL : lh;
}
EXPORT_SYMBOL(seq_list_next_rcu);
/**
* seq_hlist_start - start an iteration of a hlist
* @head: the head of the hlist
* @pos: the start position of the sequence
*
* Called at seq_file->op->start().
*/
struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
{
struct hlist_node *node;
hlist_for_each(node, head)
if (pos-- == 0)
return node;
return NULL;
}
EXPORT_SYMBOL(seq_hlist_start);
/**
* seq_hlist_start_head - start an iteration of a hlist
* @head: the head of the hlist
* @pos: the start position of the sequence
*
* Called at seq_file->op->start(). Call this function if you want to
* print a header at the top of the output.
*/
struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
{
if (!pos)
return SEQ_START_TOKEN;
return seq_hlist_start(head, pos - 1);
}
EXPORT_SYMBOL(seq_hlist_start_head);
/**
* seq_hlist_next - move to the next position of the hlist
* @v: the current iterator
* @head: the head of the hlist
* @ppos: the current position
*
* Called at seq_file->op->next().
*/
struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
loff_t *ppos)
{
struct hlist_node *node = v;
++*ppos;
if (v == SEQ_START_TOKEN)
return head->first;
else
return node->next;
}
EXPORT_SYMBOL(seq_hlist_next);
/**
* seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
* @head: the head of the hlist
* @pos: the start position of the sequence
*
* Called at seq_file->op->start().
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
loff_t pos)
{
struct hlist_node *node;
__hlist_for_each_rcu(node, head)
if (pos-- == 0)
return node;
return NULL;
}
EXPORT_SYMBOL(seq_hlist_start_rcu);
/**
* seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
* @head: the head of the hlist
* @pos: the start position of the sequence
*
* Called at seq_file->op->start(). Call this function if you want to
* print a header at the top of the output.
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
loff_t pos)
{
if (!pos)
return SEQ_START_TOKEN;
return seq_hlist_start_rcu(head, pos - 1);
}
EXPORT_SYMBOL(seq_hlist_start_head_rcu);
/**
* seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
* @v: the current iterator
* @head: the head of the hlist
* @ppos: the current position
*
* Called at seq_file->op->next().
*
* This list-traversal primitive may safely run concurrently with
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
struct hlist_node *seq_hlist_next_rcu(void *v,
struct hlist_head *head,
loff_t *ppos)
{
struct hlist_node *node = v;
++*ppos;
if (v == SEQ_START_TOKEN)
return rcu_dereference(head->first);
else
return rcu_dereference(node->next);
}
EXPORT_SYMBOL(seq_hlist_next_rcu);
/**
* seq_hlist_start_percpu - start an iteration of a percpu hlist array
* @head: pointer to percpu array of struct hlist_heads
* @cpu: pointer to cpu "cursor"
* @pos: start position of sequence
*
* Called at seq_file->op->start().
*/
struct hlist_node *
seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
{
struct hlist_node *node;
for_each_possible_cpu(*cpu) {
hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
if (pos-- == 0)
return node;
}
}
return NULL;
}
EXPORT_SYMBOL(seq_hlist_start_percpu);
/**
* seq_hlist_next_percpu - move to the next position of the percpu hlist array
* @v: pointer to current hlist_node
* @head: pointer to percpu array of struct hlist_heads
* @cpu: pointer to cpu "cursor"
* @pos: start position of sequence
*
* Called at seq_file->op->next().
*/
struct hlist_node *
seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
int *cpu, loff_t *pos)
{
struct hlist_node *node = v;
++*pos;
if (node->next)
return node->next;
for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
*cpu = cpumask_next(*cpu, cpu_possible_mask)) {
struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
if (!hlist_empty(bucket))
return bucket->first;
}
return NULL;
}
EXPORT_SYMBOL(seq_hlist_next_percpu);
void __init seq_file_init(void)
{
seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC);
}
| linux-master | fs/seq_file.c |
// SPDX-License-Identifier: GPL-2.0
/*
* fs/timerfd.c
*
* Copyright (C) 2007 Davide Libenzi <[email protected]>
*
*
* Thanks to Thomas Gleixner for code reviews and useful comments.
*
*/
#include <linux/alarmtimer.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/time.h>
#include <linux/hrtimer.h>
#include <linux/anon_inodes.h>
#include <linux/timerfd.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/rcupdate.h>
#include <linux/time_namespace.h>
struct timerfd_ctx {
union {
struct hrtimer tmr;
struct alarm alarm;
} t;
ktime_t tintv;
ktime_t moffs;
wait_queue_head_t wqh;
u64 ticks;
int clockid;
short unsigned expired;
short unsigned settime_flags; /* to show in fdinfo */
struct rcu_head rcu;
struct list_head clist;
spinlock_t cancel_lock;
bool might_cancel;
};
static LIST_HEAD(cancel_list);
static DEFINE_SPINLOCK(cancel_lock);
static inline bool isalarm(struct timerfd_ctx *ctx)
{
return ctx->clockid == CLOCK_REALTIME_ALARM ||
ctx->clockid == CLOCK_BOOTTIME_ALARM;
}
/*
* This gets called when the timer event triggers. We set the "expired"
* flag, but we do not re-arm the timer (in case it's necessary,
* tintv != 0) until the timer is accessed.
*/
static void timerfd_triggered(struct timerfd_ctx *ctx)
{
unsigned long flags;
spin_lock_irqsave(&ctx->wqh.lock, flags);
ctx->expired = 1;
ctx->ticks++;
wake_up_locked_poll(&ctx->wqh, EPOLLIN);
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
}
static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
{
struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx,
t.tmr);
timerfd_triggered(ctx);
return HRTIMER_NORESTART;
}
static enum alarmtimer_restart timerfd_alarmproc(struct alarm *alarm,
ktime_t now)
{
struct timerfd_ctx *ctx = container_of(alarm, struct timerfd_ctx,
t.alarm);
timerfd_triggered(ctx);
return ALARMTIMER_NORESTART;
}
/*
* Called when the clock was set to cancel the timers in the cancel
* list. This will wake up processes waiting on these timers. The
* wake-up requires ctx->ticks to be non zero, therefore we increment
* it before calling wake_up_locked().
*/
void timerfd_clock_was_set(void)
{
ktime_t moffs = ktime_mono_to_real(0);
struct timerfd_ctx *ctx;
unsigned long flags;
rcu_read_lock();
list_for_each_entry_rcu(ctx, &cancel_list, clist) {
if (!ctx->might_cancel)
continue;
spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ctx->moffs != moffs) {
ctx->moffs = KTIME_MAX;
ctx->ticks++;
wake_up_locked_poll(&ctx->wqh, EPOLLIN);
}
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
}
rcu_read_unlock();
}
static void timerfd_resume_work(struct work_struct *work)
{
timerfd_clock_was_set();
}
static DECLARE_WORK(timerfd_work, timerfd_resume_work);
/*
* Invoked from timekeeping_resume(). Defer the actual update to work so
* timerfd_clock_was_set() runs in task context.
*/
void timerfd_resume(void)
{
schedule_work(&timerfd_work);
}
static void __timerfd_remove_cancel(struct timerfd_ctx *ctx)
{
if (ctx->might_cancel) {
ctx->might_cancel = false;
spin_lock(&cancel_lock);
list_del_rcu(&ctx->clist);
spin_unlock(&cancel_lock);
}
}
static void timerfd_remove_cancel(struct timerfd_ctx *ctx)
{
spin_lock(&ctx->cancel_lock);
__timerfd_remove_cancel(ctx);
spin_unlock(&ctx->cancel_lock);
}
static bool timerfd_canceled(struct timerfd_ctx *ctx)
{
if (!ctx->might_cancel || ctx->moffs != KTIME_MAX)
return false;
ctx->moffs = ktime_mono_to_real(0);
return true;
}
static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags)
{
spin_lock(&ctx->cancel_lock);
if ((ctx->clockid == CLOCK_REALTIME ||
ctx->clockid == CLOCK_REALTIME_ALARM) &&
(flags & TFD_TIMER_ABSTIME) && (flags & TFD_TIMER_CANCEL_ON_SET)) {
if (!ctx->might_cancel) {
ctx->might_cancel = true;
spin_lock(&cancel_lock);
list_add_rcu(&ctx->clist, &cancel_list);
spin_unlock(&cancel_lock);
}
} else {
__timerfd_remove_cancel(ctx);
}
spin_unlock(&ctx->cancel_lock);
}
static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
{
ktime_t remaining;
if (isalarm(ctx))
remaining = alarm_expires_remaining(&ctx->t.alarm);
else
remaining = hrtimer_expires_remaining_adjusted(&ctx->t.tmr);
return remaining < 0 ? 0: remaining;
}
static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
const struct itimerspec64 *ktmr)
{
enum hrtimer_mode htmode;
ktime_t texp;
int clockid = ctx->clockid;
htmode = (flags & TFD_TIMER_ABSTIME) ?
HRTIMER_MODE_ABS: HRTIMER_MODE_REL;
texp = timespec64_to_ktime(ktmr->it_value);
ctx->expired = 0;
ctx->ticks = 0;
ctx->tintv = timespec64_to_ktime(ktmr->it_interval);
if (isalarm(ctx)) {
alarm_init(&ctx->t.alarm,
ctx->clockid == CLOCK_REALTIME_ALARM ?
ALARM_REALTIME : ALARM_BOOTTIME,
timerfd_alarmproc);
} else {
hrtimer_init(&ctx->t.tmr, clockid, htmode);
hrtimer_set_expires(&ctx->t.tmr, texp);
ctx->t.tmr.function = timerfd_tmrproc;
}
if (texp != 0) {
if (flags & TFD_TIMER_ABSTIME)
texp = timens_ktime_to_host(clockid, texp);
if (isalarm(ctx)) {
if (flags & TFD_TIMER_ABSTIME)
alarm_start(&ctx->t.alarm, texp);
else
alarm_start_relative(&ctx->t.alarm, texp);
} else {
hrtimer_start(&ctx->t.tmr, texp, htmode);
}
if (timerfd_canceled(ctx))
return -ECANCELED;
}
ctx->settime_flags = flags & TFD_SETTIME_FLAGS;
return 0;
}
static int timerfd_release(struct inode *inode, struct file *file)
{
struct timerfd_ctx *ctx = file->private_data;
timerfd_remove_cancel(ctx);
if (isalarm(ctx))
alarm_cancel(&ctx->t.alarm);
else
hrtimer_cancel(&ctx->t.tmr);
kfree_rcu(ctx, rcu);
return 0;
}
static __poll_t timerfd_poll(struct file *file, poll_table *wait)
{
struct timerfd_ctx *ctx = file->private_data;
__poll_t events = 0;
unsigned long flags;
poll_wait(file, &ctx->wqh, wait);
spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ctx->ticks)
events |= EPOLLIN;
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
return events;
}
static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
loff_t *ppos)
{
struct timerfd_ctx *ctx = file->private_data;
ssize_t res;
u64 ticks = 0;
if (count < sizeof(ticks))
return -EINVAL;
spin_lock_irq(&ctx->wqh.lock);
if (file->f_flags & O_NONBLOCK)
res = -EAGAIN;
else
res = wait_event_interruptible_locked_irq(ctx->wqh, ctx->ticks);
/*
* If clock has changed, we do not care about the
* ticks and we do not rearm the timer. Userspace must
* reevaluate anyway.
*/
if (timerfd_canceled(ctx)) {
ctx->ticks = 0;
ctx->expired = 0;
res = -ECANCELED;
}
if (ctx->ticks) {
ticks = ctx->ticks;
if (ctx->expired && ctx->tintv) {
/*
* If tintv != 0, this is a periodic timer that
* needs to be re-armed. We avoid doing it in the timer
* callback to avoid DoS attacks specifying a very
* short timer period.
*/
if (isalarm(ctx)) {
ticks += alarm_forward_now(
&ctx->t.alarm, ctx->tintv) - 1;
alarm_restart(&ctx->t.alarm);
} else {
ticks += hrtimer_forward_now(&ctx->t.tmr,
ctx->tintv) - 1;
hrtimer_restart(&ctx->t.tmr);
}
}
ctx->expired = 0;
ctx->ticks = 0;
}
spin_unlock_irq(&ctx->wqh.lock);
if (ticks)
res = put_user(ticks, (u64 __user *) buf) ? -EFAULT: sizeof(ticks);
return res;
}
#ifdef CONFIG_PROC_FS
static void timerfd_show(struct seq_file *m, struct file *file)
{
struct timerfd_ctx *ctx = file->private_data;
struct timespec64 value, interval;
spin_lock_irq(&ctx->wqh.lock);
value = ktime_to_timespec64(timerfd_get_remaining(ctx));
interval = ktime_to_timespec64(ctx->tintv);
spin_unlock_irq(&ctx->wqh.lock);
seq_printf(m,
"clockid: %d\n"
"ticks: %llu\n"
"settime flags: 0%o\n"
"it_value: (%llu, %llu)\n"
"it_interval: (%llu, %llu)\n",
ctx->clockid,
(unsigned long long)ctx->ticks,
ctx->settime_flags,
(unsigned long long)value.tv_sec,
(unsigned long long)value.tv_nsec,
(unsigned long long)interval.tv_sec,
(unsigned long long)interval.tv_nsec);
}
#else
#define timerfd_show NULL
#endif
#ifdef CONFIG_CHECKPOINT_RESTORE
static long timerfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct timerfd_ctx *ctx = file->private_data;
int ret = 0;
switch (cmd) {
case TFD_IOC_SET_TICKS: {
u64 ticks;
if (copy_from_user(&ticks, (u64 __user *)arg, sizeof(ticks)))
return -EFAULT;
if (!ticks)
return -EINVAL;
spin_lock_irq(&ctx->wqh.lock);
if (!timerfd_canceled(ctx)) {
ctx->ticks = ticks;
wake_up_locked_poll(&ctx->wqh, EPOLLIN);
} else
ret = -ECANCELED;
spin_unlock_irq(&ctx->wqh.lock);
break;
}
default:
ret = -ENOTTY;
break;
}
return ret;
}
#else
#define timerfd_ioctl NULL
#endif
static const struct file_operations timerfd_fops = {
.release = timerfd_release,
.poll = timerfd_poll,
.read = timerfd_read,
.llseek = noop_llseek,
.show_fdinfo = timerfd_show,
.unlocked_ioctl = timerfd_ioctl,
};
static int timerfd_fget(int fd, struct fd *p)
{
struct fd f = fdget(fd);
if (!f.file)
return -EBADF;
if (f.file->f_op != &timerfd_fops) {
fdput(f);
return -EINVAL;
}
*p = f;
return 0;
}
SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
{
int ufd;
struct timerfd_ctx *ctx;
/* Check the TFD_* constants for consistency. */
BUILD_BUG_ON(TFD_CLOEXEC != O_CLOEXEC);
BUILD_BUG_ON(TFD_NONBLOCK != O_NONBLOCK);
if ((flags & ~TFD_CREATE_FLAGS) ||
(clockid != CLOCK_MONOTONIC &&
clockid != CLOCK_REALTIME &&
clockid != CLOCK_REALTIME_ALARM &&
clockid != CLOCK_BOOTTIME &&
clockid != CLOCK_BOOTTIME_ALARM))
return -EINVAL;
if ((clockid == CLOCK_REALTIME_ALARM ||
clockid == CLOCK_BOOTTIME_ALARM) &&
!capable(CAP_WAKE_ALARM))
return -EPERM;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
init_waitqueue_head(&ctx->wqh);
spin_lock_init(&ctx->cancel_lock);
ctx->clockid = clockid;
if (isalarm(ctx))
alarm_init(&ctx->t.alarm,
ctx->clockid == CLOCK_REALTIME_ALARM ?
ALARM_REALTIME : ALARM_BOOTTIME,
timerfd_alarmproc);
else
hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS);
ctx->moffs = ktime_mono_to_real(0);
ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));
if (ufd < 0)
kfree(ctx);
return ufd;
}
static int do_timerfd_settime(int ufd, int flags,
const struct itimerspec64 *new,
struct itimerspec64 *old)
{
struct fd f;
struct timerfd_ctx *ctx;
int ret;
if ((flags & ~TFD_SETTIME_FLAGS) ||
!itimerspec64_valid(new))
return -EINVAL;
ret = timerfd_fget(ufd, &f);
if (ret)
return ret;
ctx = f.file->private_data;
if (isalarm(ctx) && !capable(CAP_WAKE_ALARM)) {
fdput(f);
return -EPERM;
}
timerfd_setup_cancel(ctx, flags);
/*
* We need to stop the existing timer before reprogramming
* it to the new values.
*/
for (;;) {
spin_lock_irq(&ctx->wqh.lock);
if (isalarm(ctx)) {
if (alarm_try_to_cancel(&ctx->t.alarm) >= 0)
break;
} else {
if (hrtimer_try_to_cancel(&ctx->t.tmr) >= 0)
break;
}
spin_unlock_irq(&ctx->wqh.lock);
if (isalarm(ctx))
hrtimer_cancel_wait_running(&ctx->t.alarm.timer);
else
hrtimer_cancel_wait_running(&ctx->t.tmr);
}
/*
* If the timer is expired and it's periodic, we need to advance it
* because the caller may want to know the previous expiration time.
* We do not update "ticks" and "expired" since the timer will be
* re-programmed again in the following timerfd_setup() call.
*/
if (ctx->expired && ctx->tintv) {
if (isalarm(ctx))
alarm_forward_now(&ctx->t.alarm, ctx->tintv);
else
hrtimer_forward_now(&ctx->t.tmr, ctx->tintv);
}
old->it_value = ktime_to_timespec64(timerfd_get_remaining(ctx));
old->it_interval = ktime_to_timespec64(ctx->tintv);
/*
* Re-program the timer to the new value ...
*/
ret = timerfd_setup(ctx, flags, new);
spin_unlock_irq(&ctx->wqh.lock);
fdput(f);
return ret;
}
static int do_timerfd_gettime(int ufd, struct itimerspec64 *t)
{
struct fd f;
struct timerfd_ctx *ctx;
int ret = timerfd_fget(ufd, &f);
if (ret)
return ret;
ctx = f.file->private_data;
spin_lock_irq(&ctx->wqh.lock);
if (ctx->expired && ctx->tintv) {
ctx->expired = 0;
if (isalarm(ctx)) {
ctx->ticks +=
alarm_forward_now(
&ctx->t.alarm, ctx->tintv) - 1;
alarm_restart(&ctx->t.alarm);
} else {
ctx->ticks +=
hrtimer_forward_now(&ctx->t.tmr, ctx->tintv)
- 1;
hrtimer_restart(&ctx->t.tmr);
}
}
t->it_value = ktime_to_timespec64(timerfd_get_remaining(ctx));
t->it_interval = ktime_to_timespec64(ctx->tintv);
spin_unlock_irq(&ctx->wqh.lock);
fdput(f);
return 0;
}
SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
const struct __kernel_itimerspec __user *, utmr,
struct __kernel_itimerspec __user *, otmr)
{
struct itimerspec64 new, old;
int ret;
if (get_itimerspec64(&new, utmr))
return -EFAULT;
ret = do_timerfd_settime(ufd, flags, &new, &old);
if (ret)
return ret;
if (otmr && put_itimerspec64(&old, otmr))
return -EFAULT;
return ret;
}
SYSCALL_DEFINE2(timerfd_gettime, int, ufd, struct __kernel_itimerspec __user *, otmr)
{
struct itimerspec64 kotmr;
int ret = do_timerfd_gettime(ufd, &kotmr);
if (ret)
return ret;
return put_itimerspec64(&kotmr, otmr) ? -EFAULT : 0;
}
#ifdef CONFIG_COMPAT_32BIT_TIME
SYSCALL_DEFINE4(timerfd_settime32, int, ufd, int, flags,
const struct old_itimerspec32 __user *, utmr,
struct old_itimerspec32 __user *, otmr)
{
struct itimerspec64 new, old;
int ret;
if (get_old_itimerspec32(&new, utmr))
return -EFAULT;
ret = do_timerfd_settime(ufd, flags, &new, &old);
if (ret)
return ret;
if (otmr && put_old_itimerspec32(&old, otmr))
return -EFAULT;
return ret;
}
SYSCALL_DEFINE2(timerfd_gettime32, int, ufd,
struct old_itimerspec32 __user *, otmr)
{
struct itimerspec64 kotmr;
int ret = do_timerfd_gettime(ufd, &kotmr);
if (ret)
return ret;
return put_old_itimerspec32(&kotmr, otmr) ? -EFAULT : 0;
}
#endif
| linux-master | fs/timerfd.c |
// SPDX-License-Identifier: GPL-2.0
/****************************************************************************/
/*
* linux/fs/binfmt_flat.c
*
* Copyright (C) 2000-2003 David McCullough <[email protected]>
* Copyright (C) 2002 Greg Ungerer <[email protected]>
* Copyright (C) 2002 SnapGear, by Paul Dale <[email protected]>
* Copyright (C) 2000, 2001 Lineo, by David McCullough <[email protected]>
* based heavily on:
*
* linux/fs/binfmt_aout.c:
* Copyright (C) 1991, 1992, 1996 Linus Torvalds
* linux/fs/binfmt_flat.c for 2.0 kernel
* Copyright (C) 1998 Kenneth Albanowski <[email protected]>
* JAN/99 -- coded full program relocation ([email protected])
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/init.h>
#include <linux/flat.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <asm/cacheflush.h>
#include <asm/page.h>
#include <asm/flat.h>
#ifndef flat_get_relocate_addr
#define flat_get_relocate_addr(rel) (rel)
#endif
/****************************************************************************/
/*
* User data (data section and bss) needs to be aligned.
* We pick 0x20 here because it is the max value elf2flt has always
* used in producing FLAT files, and because it seems to be large
* enough to make all the gcc alignment related tests happy.
*/
#define FLAT_DATA_ALIGN (0x20)
/*
* User data (stack) also needs to be aligned.
* Here we can be a bit looser than the data sections since this
* needs to only meet arch ABI requirements.
*/
#define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
#define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
#define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
#define MAX_SHARED_LIBS (1)
#ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET
#define DATA_START_OFFSET_WORDS (0)
#else
#define DATA_START_OFFSET_WORDS (MAX_SHARED_LIBS)
#endif
struct lib_info {
struct {
unsigned long start_code; /* Start of text segment */
unsigned long start_data; /* Start of data segment */
unsigned long start_brk; /* End of data segment */
unsigned long text_len; /* Length of text segment */
unsigned long entry; /* Start address for this module */
unsigned long build_date; /* When this one was compiled */
bool loaded; /* Has this library been loaded? */
} lib_list[MAX_SHARED_LIBS];
};
static int load_flat_binary(struct linux_binprm *);
static struct linux_binfmt flat_format = {
.module = THIS_MODULE,
.load_binary = load_flat_binary,
};
/****************************************************************************/
/*
* create_flat_tables() parses the env- and arg-strings in new user
* memory and creates the pointer tables from them, and puts their
* addresses on the "stack", recording the new stack pointer value.
*/
static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
{
char __user *p;
unsigned long __user *sp;
long i, len;
p = (char __user *)arg_start;
sp = (unsigned long __user *)current->mm->start_stack;
sp -= bprm->envc + 1;
sp -= bprm->argc + 1;
if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK))
sp -= 2; /* argvp + envp */
sp -= 1; /* &argc */
current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
sp = (unsigned long __user *)current->mm->start_stack;
if (put_user(bprm->argc, sp++))
return -EFAULT;
if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {
unsigned long argv, envp;
argv = (unsigned long)(sp + 2);
envp = (unsigned long)(sp + 2 + bprm->argc + 1);
if (put_user(argv, sp++) || put_user(envp, sp++))
return -EFAULT;
}
current->mm->arg_start = (unsigned long)p;
for (i = bprm->argc; i > 0; i--) {
if (put_user((unsigned long)p, sp++))
return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(0, sp++))
return -EFAULT;
current->mm->arg_end = (unsigned long)p;
current->mm->env_start = (unsigned long) p;
for (i = bprm->envc; i > 0; i--) {
if (put_user((unsigned long)p, sp++))
return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(0, sp++))
return -EFAULT;
current->mm->env_end = (unsigned long)p;
return 0;
}
/****************************************************************************/
#ifdef CONFIG_BINFMT_ZFLAT
#include <linux/zlib.h>
#define LBUFSIZE 4000
/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
#define RESERVED 0xC0 /* bit 6,7: reserved */
static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,
long len, int fd)
{
unsigned char *buf;
z_stream strm;
int ret, retval;
pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);
memset(&strm, 0, sizeof(strm));
strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
if (!strm.workspace)
return -ENOMEM;
buf = kmalloc(LBUFSIZE, GFP_KERNEL);
if (!buf) {
retval = -ENOMEM;
goto out_free;
}
/* Read in first chunk of data and parse gzip header. */
ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
strm.next_in = buf;
strm.avail_in = ret;
strm.total_in = 0;
retval = -ENOEXEC;
/* Check minimum size -- gzip header */
if (ret < 10) {
pr_debug("file too small?\n");
goto out_free_buf;
}
/* Check gzip magic number */
if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
pr_debug("unknown compression magic?\n");
goto out_free_buf;
}
/* Check gzip method */
if (buf[2] != 8) {
pr_debug("unknown compression method?\n");
goto out_free_buf;
}
/* Check gzip flags */
if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
(buf[3] & RESERVED)) {
pr_debug("unknown flags?\n");
goto out_free_buf;
}
ret = 10;
if (buf[3] & EXTRA_FIELD) {
ret += 2 + buf[10] + (buf[11] << 8);
if (unlikely(ret >= LBUFSIZE)) {
pr_debug("buffer overflow (EXTRA)?\n");
goto out_free_buf;
}
}
if (buf[3] & ORIG_NAME) {
while (ret < LBUFSIZE && buf[ret++] != 0)
;
if (unlikely(ret == LBUFSIZE)) {
pr_debug("buffer overflow (ORIG_NAME)?\n");
goto out_free_buf;
}
}
if (buf[3] & COMMENT) {
while (ret < LBUFSIZE && buf[ret++] != 0)
;
if (unlikely(ret == LBUFSIZE)) {
pr_debug("buffer overflow (COMMENT)?\n");
goto out_free_buf;
}
}
strm.next_in += ret;
strm.avail_in -= ret;
strm.next_out = dst;
strm.avail_out = len;
strm.total_out = 0;
if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
pr_debug("zlib init failed?\n");
goto out_free_buf;
}
while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
if (ret <= 0)
break;
len -= ret;
strm.next_in = buf;
strm.avail_in = ret;
strm.total_in = 0;
}
if (ret < 0) {
pr_debug("decompression failed (%d), %s\n",
ret, strm.msg);
goto out_zlib;
}
retval = 0;
out_zlib:
zlib_inflateEnd(&strm);
out_free_buf:
kfree(buf);
out_free:
kfree(strm.workspace);
return retval;
}
#endif /* CONFIG_BINFMT_ZFLAT */
/****************************************************************************/
static unsigned long
calc_reloc(unsigned long r, struct lib_info *p)
{
unsigned long addr;
unsigned long start_brk;
unsigned long start_data;
unsigned long text_len;
unsigned long start_code;
start_brk = p->lib_list[0].start_brk;
start_data = p->lib_list[0].start_data;
start_code = p->lib_list[0].start_code;
text_len = p->lib_list[0].text_len;
if (r > start_brk - start_data + text_len) {
pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
r, start_brk-start_data+text_len, text_len);
goto failed;
}
if (r < text_len) /* In text segment */
addr = r + start_code;
else /* In data segment */
addr = r - text_len + start_data;
/* Range checked already above so doing the range tests is redundant...*/
return addr;
failed:
pr_cont(", killing %s!\n", current->comm);
send_sig(SIGSEGV, current, 0);
return RELOC_FAILED;
}
/****************************************************************************/
#ifdef CONFIG_BINFMT_FLAT_OLD
static void old_reloc(unsigned long rl)
{
static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
flat_v2_reloc_t r;
unsigned long __user *ptr;
unsigned long val;
r.value = rl;
#if defined(CONFIG_COLDFIRE)
ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
#else
ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
#endif
get_user(val, ptr);
pr_debug("Relocation of variable at DATASEG+%x "
"(address %p, currently %lx) into segment %s\n",
r.reloc.offset, ptr, val, segment[r.reloc.type]);
switch (r.reloc.type) {
case OLD_FLAT_RELOC_TYPE_TEXT:
val += current->mm->start_code;
break;
case OLD_FLAT_RELOC_TYPE_DATA:
val += current->mm->start_data;
break;
case OLD_FLAT_RELOC_TYPE_BSS:
val += current->mm->end_data;
break;
default:
pr_err("Unknown relocation type=%x\n", r.reloc.type);
break;
}
put_user(val, ptr);
pr_debug("Relocation became %lx\n", val);
}
#endif /* CONFIG_BINFMT_FLAT_OLD */
/****************************************************************************/
static inline u32 __user *skip_got_header(u32 __user *rp)
{
if (IS_ENABLED(CONFIG_RISCV)) {
/*
* RISC-V has a 16 byte GOT PLT header for elf64-riscv
* and 8 byte GOT PLT header for elf32-riscv.
* Skip the whole GOT PLT header, since it is reserved
* for the dynamic linker (ld.so).
*/
u32 rp_val0, rp_val1;
if (get_user(rp_val0, rp))
return rp;
if (get_user(rp_val1, rp + 1))
return rp;
if (rp_val0 == 0xffffffff && rp_val1 == 0xffffffff)
rp += 4;
else if (rp_val0 == 0xffffffff)
rp += 2;
}
return rp;
}
static int load_flat_file(struct linux_binprm *bprm,
struct lib_info *libinfo, unsigned long *extra_stack)
{
struct flat_hdr *hdr;
unsigned long textpos, datapos, realdatastart;
u32 text_len, data_len, bss_len, stack_len, full_data, flags;
unsigned long len, memp, memp_size, extra, rlim;
__be32 __user *reloc;
u32 __user *rp;
int i, rev, relocs;
loff_t fpos;
unsigned long start_code, end_code;
ssize_t result;
int ret;
hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
text_len = ntohl(hdr->data_start);
data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
stack_len = ntohl(hdr->stack_size);
if (extra_stack) {
stack_len += *extra_stack;
*extra_stack = stack_len;
}
relocs = ntohl(hdr->reloc_count);
flags = ntohl(hdr->flags);
rev = ntohl(hdr->rev);
full_data = data_len + relocs * sizeof(unsigned long);
if (strncmp(hdr->magic, "bFLT", 4)) {
/*
* Previously, here was a printk to tell people
* "BINFMT_FLAT: bad header magic".
* But for the kernel which also use ELF FD-PIC format, this
* error message is confusing.
* because a lot of people do not manage to produce good
*/
ret = -ENOEXEC;
goto err;
}
if (flags & FLAT_FLAG_KTRACE)
pr_info("Loading file: %s\n", bprm->filename);
#ifdef CONFIG_BINFMT_FLAT_OLD
if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
rev, FLAT_VERSION, OLD_FLAT_VERSION);
ret = -ENOEXEC;
goto err;
}
/*
* fix up the flags for the older format, there were all kinds
* of endian hacks, this only works for the simple cases
*/
if (rev == OLD_FLAT_VERSION &&
(flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))
flags = FLAT_FLAG_RAM;
#else /* CONFIG_BINFMT_FLAT_OLD */
if (rev != FLAT_VERSION) {
pr_err("bad flat file version 0x%x (supported 0x%lx)\n",
rev, FLAT_VERSION);
ret = -ENOEXEC;
goto err;
}
#endif /* !CONFIG_BINFMT_FLAT_OLD */
/*
* Make sure the header params are sane.
* 28 bits (256 MB) is way more than reasonable in this case.
* If some top bits are set we have probable binary corruption.
*/
if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
pr_err("bad header\n");
ret = -ENOEXEC;
goto err;
}
#ifndef CONFIG_BINFMT_ZFLAT
if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
pr_err("Support for ZFLAT executables is not enabled.\n");
ret = -ENOEXEC;
goto err;
}
#endif
/*
* Check initial limits. This avoids letting people circumvent
* size limits imposed on them by creating programs with large
* arrays in the data or bss.
*/
rlim = rlimit(RLIMIT_DATA);
if (rlim >= RLIM_INFINITY)
rlim = ~0;
if (data_len + bss_len > rlim) {
ret = -ENOMEM;
goto err;
}
/* Flush all traces of the currently running executable */
ret = begin_new_exec(bprm);
if (ret)
goto err;
/* OK, This is the point of no return */
set_personality(PER_LINUX_32BIT);
setup_new_exec(bprm);
/*
* calculate the extra space we need to map in
*/
extra = max_t(unsigned long, bss_len + stack_len,
relocs * sizeof(unsigned long));
/*
* there are a couple of cases here, the separate code/data
* case, and then the fully copied to RAM case which lumps
* it all together.
*/
if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
/*
* this should give us a ROM ptr, but if it doesn't we don't
* really care
*/
pr_debug("ROM mapping of file (we hope)\n");
textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
MAP_PRIVATE, 0);
if (!textpos || IS_ERR_VALUE(textpos)) {
ret = textpos;
if (!textpos)
ret = -ENOMEM;
pr_err("Unable to mmap process text, errno %d\n", ret);
goto err;
}
len = data_len + extra +
DATA_START_OFFSET_WORDS * sizeof(unsigned long);
len = PAGE_ALIGN(len);
realdatastart = vm_mmap(NULL, 0, len,
PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
ret = realdatastart;
if (!realdatastart)
ret = -ENOMEM;
pr_err("Unable to allocate RAM for process data, "
"errno %d\n", ret);
vm_munmap(textpos, text_len);
goto err;
}
datapos = ALIGN(realdatastart +
DATA_START_OFFSET_WORDS * sizeof(unsigned long),
FLAT_DATA_ALIGN);
pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
data_len + bss_len + stack_len, datapos);
fpos = ntohl(hdr->data_start);
#ifdef CONFIG_BINFMT_ZFLAT
if (flags & FLAT_FLAG_GZDATA) {
result = decompress_exec(bprm, fpos, (char *)datapos,
full_data, 0);
} else
#endif
{
result = read_code(bprm->file, datapos, fpos,
full_data);
}
if (IS_ERR_VALUE(result)) {
ret = result;
pr_err("Unable to read data+bss, errno %d\n", ret);
vm_munmap(textpos, text_len);
vm_munmap(realdatastart, len);
goto err;
}
reloc = (__be32 __user *)
(datapos + (ntohl(hdr->reloc_start) - text_len));
memp = realdatastart;
memp_size = len;
} else {
len = text_len + data_len + extra +
DATA_START_OFFSET_WORDS * sizeof(u32);
len = PAGE_ALIGN(len);
textpos = vm_mmap(NULL, 0, len,
PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
if (!textpos || IS_ERR_VALUE(textpos)) {
ret = textpos;
if (!textpos)
ret = -ENOMEM;
pr_err("Unable to allocate RAM for process text/data, "
"errno %d\n", ret);
goto err;
}
realdatastart = textpos + ntohl(hdr->data_start);
datapos = ALIGN(realdatastart +
DATA_START_OFFSET_WORDS * sizeof(u32),
FLAT_DATA_ALIGN);
reloc = (__be32 __user *)
(datapos + (ntohl(hdr->reloc_start) - text_len));
memp = textpos;
memp_size = len;
#ifdef CONFIG_BINFMT_ZFLAT
/*
* load it all in and treat it like a RAM load from now on
*/
if (flags & FLAT_FLAG_GZIP) {
#ifndef CONFIG_MMU
result = decompress_exec(bprm, sizeof(struct flat_hdr),
(((char *)textpos) + sizeof(struct flat_hdr)),
(text_len + full_data
- sizeof(struct flat_hdr)),
0);
memmove((void *) datapos, (void *) realdatastart,
full_data);
#else
/*
* This is used on MMU systems mainly for testing.
* Let's use a kernel buffer to simplify things.
*/
long unz_text_len = text_len - sizeof(struct flat_hdr);
long unz_len = unz_text_len + full_data;
char *unz_data = vmalloc(unz_len);
if (!unz_data) {
result = -ENOMEM;
} else {
result = decompress_exec(bprm, sizeof(struct flat_hdr),
unz_data, unz_len, 0);
if (result == 0 &&
(copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
unz_data, unz_text_len) ||
copy_to_user((void __user *)datapos,
unz_data + unz_text_len, full_data)))
result = -EFAULT;
vfree(unz_data);
}
#endif
} else if (flags & FLAT_FLAG_GZDATA) {
result = read_code(bprm->file, textpos, 0, text_len);
if (!IS_ERR_VALUE(result)) {
#ifndef CONFIG_MMU
result = decompress_exec(bprm, text_len, (char *) datapos,
full_data, 0);
#else
char *unz_data = vmalloc(full_data);
if (!unz_data) {
result = -ENOMEM;
} else {
result = decompress_exec(bprm, text_len,
unz_data, full_data, 0);
if (result == 0 &&
copy_to_user((void __user *)datapos,
unz_data, full_data))
result = -EFAULT;
vfree(unz_data);
}
#endif
}
} else
#endif /* CONFIG_BINFMT_ZFLAT */
{
result = read_code(bprm->file, textpos, 0, text_len);
if (!IS_ERR_VALUE(result))
result = read_code(bprm->file, datapos,
ntohl(hdr->data_start),
full_data);
}
if (IS_ERR_VALUE(result)) {
ret = result;
pr_err("Unable to read code+data+bss, errno %d\n", ret);
vm_munmap(textpos, text_len + data_len + extra +
DATA_START_OFFSET_WORDS * sizeof(u32));
goto err;
}
}
start_code = textpos + sizeof(struct flat_hdr);
end_code = textpos + text_len;
text_len -= sizeof(struct flat_hdr); /* the real code len */
/* The main program needs a little extra setup in the task structure */
current->mm->start_code = start_code;
current->mm->end_code = end_code;
current->mm->start_data = datapos;
current->mm->end_data = datapos + data_len;
/*
* set up the brk stuff, uses any slack left in data/bss/stack
* allocation. We put the brk after the bss (between the bss
* and stack) like other platforms.
* Userspace code relies on the stack pointer starting out at
* an address right at the end of a page.
*/
current->mm->start_brk = datapos + data_len + bss_len;
current->mm->brk = (current->mm->start_brk + 3) & ~3;
#ifndef CONFIG_MMU
current->mm->context.end_brk = memp + memp_size - stack_len;
#endif
if (flags & FLAT_FLAG_KTRACE) {
pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
"Load", bprm->filename,
start_code, end_code, datapos, datapos + data_len,
datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
}
/* Store the current module values into the global library structure */
libinfo->lib_list[0].start_code = start_code;
libinfo->lib_list[0].start_data = datapos;
libinfo->lib_list[0].start_brk = datapos + data_len + bss_len;
libinfo->lib_list[0].text_len = text_len;
libinfo->lib_list[0].loaded = 1;
libinfo->lib_list[0].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
libinfo->lib_list[0].build_date = ntohl(hdr->build_date);
/*
* We just load the allocations into some temporary memory to
* help simplify all this mumbo jumbo
*
* We've got two different sections of relocation entries.
* The first is the GOT which resides at the beginning of the data segment
* and is terminated with a -1. This one can be relocated in place.
* The second is the extra relocation entries tacked after the image's
* data segment. These require a little more processing as the entry is
* really an offset into the image which contains an offset into the
* image.
*/
if (flags & FLAT_FLAG_GOTPIC) {
rp = skip_got_header((u32 __user *) datapos);
for (; ; rp++) {
u32 addr, rp_val;
if (get_user(rp_val, rp))
return -EFAULT;
if (rp_val == 0xffffffff)
break;
if (rp_val) {
addr = calc_reloc(rp_val, libinfo);
if (addr == RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}
if (put_user(addr, rp))
return -EFAULT;
}
}
}
/*
* Now run through the relocation entries.
* We've got to be careful here as C++ produces relocatable zero
* entries in the constructor and destructor tables which are then
* tested for being not zero (which will always occur unless we're
* based from address zero). This causes an endless loop as __start
* is at zero. The solution used is to not relocate zero addresses.
* This has the negative side effect of not allowing a global data
* reference to be statically initialised to _stext (I've moved
* __start to address 4 so that is okay).
*/
if (rev > OLD_FLAT_VERSION) {
for (i = 0; i < relocs; i++) {
u32 addr, relval;
__be32 tmp;
/*
* Get the address of the pointer to be
* relocated (of course, the address has to be
* relocated first).
*/
if (get_user(tmp, reloc + i))
return -EFAULT;
relval = ntohl(tmp);
addr = flat_get_relocate_addr(relval);
rp = (u32 __user *)calc_reloc(addr, libinfo);
if (rp == (u32 __user *)RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}
/* Get the pointer's value. */
ret = flat_get_addr_from_rp(rp, relval, flags, &addr);
if (unlikely(ret))
goto err;
if (addr != 0) {
/*
* Do the relocation. PIC relocs in the data section are
* already in target order
*/
if ((flags & FLAT_FLAG_GOTPIC) == 0) {
/*
* Meh, the same value can have a different
* byte order based on a flag..
*/
addr = ntohl((__force __be32)addr);
}
addr = calc_reloc(addr, libinfo);
if (addr == RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}
/* Write back the relocated pointer. */
ret = flat_put_addr_at_rp(rp, addr, relval);
if (unlikely(ret))
goto err;
}
}
#ifdef CONFIG_BINFMT_FLAT_OLD
} else {
for (i = 0; i < relocs; i++) {
__be32 relval;
if (get_user(relval, reloc + i))
return -EFAULT;
old_reloc(ntohl(relval));
}
#endif /* CONFIG_BINFMT_FLAT_OLD */
}
flush_icache_user_range(start_code, end_code);
/* zero the BSS, BRK and stack areas */
if (clear_user((void __user *)(datapos + data_len), bss_len +
(memp + memp_size - stack_len - /* end brk */
libinfo->lib_list[0].start_brk) + /* start brk */
stack_len))
return -EFAULT;
return 0;
err:
return ret;
}
/****************************************************************************/
/*
* These are the functions used to load flat style executables and shared
* libraries. There is no binary dependent code anywhere else.
*/
static int load_flat_binary(struct linux_binprm *bprm)
{
struct lib_info libinfo;
struct pt_regs *regs = current_pt_regs();
unsigned long stack_len = 0;
unsigned long start_addr;
int res;
int i, j;
memset(&libinfo, 0, sizeof(libinfo));
/*
* We have to add the size of our arguments to our stack size
* otherwise it's too easy for users to create stack overflows
* by passing in a huge argument list. And yes, we have to be
* pedantic and include space for the argv/envp array as it may have
* a lot of entries.
*/
#ifndef CONFIG_MMU
stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
#endif
stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
res = load_flat_file(bprm, &libinfo, &stack_len);
if (res < 0)
return res;
/* Update data segment pointers for all libraries */
for (i = 0; i < MAX_SHARED_LIBS; i++) {
if (!libinfo.lib_list[i].loaded)
continue;
for (j = 0; j < MAX_SHARED_LIBS; j++) {
unsigned long val = libinfo.lib_list[j].loaded ?
libinfo.lib_list[j].start_data : UNLOADED_LIB;
unsigned long __user *p = (unsigned long __user *)
libinfo.lib_list[i].start_data;
p -= j + 1;
if (put_user(val, p))
return -EFAULT;
}
}
set_binfmt(&flat_format);
#ifdef CONFIG_MMU
res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
if (!res)
res = create_flat_tables(bprm, bprm->p);
#else
/* Stash our initial stack pointer into the mm structure */
current->mm->start_stack =
((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
pr_debug("sp=%lx\n", current->mm->start_stack);
/* copy the arg pages onto the stack */
res = transfer_args_to_stack(bprm, ¤t->mm->start_stack);
if (!res)
res = create_flat_tables(bprm, current->mm->start_stack);
#endif
if (res)
return res;
/* Fake some return addresses to ensure the call chain will
* initialise library in order for us. We are required to call
* lib 1 first, then 2, ... and finally the main program (id 0).
*/
start_addr = libinfo.lib_list[0].entry;
#ifdef FLAT_PLAT_INIT
FLAT_PLAT_INIT(regs);
#endif
finalize_exec(bprm);
pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
regs, start_addr, current->mm->start_stack);
start_thread(regs, start_addr, current->mm->start_stack);
return 0;
}
/****************************************************************************/
static int __init init_flat_binfmt(void)
{
register_binfmt(&flat_format);
return 0;
}
core_initcall(init_flat_binfmt);
/****************************************************************************/
| linux-master | fs/binfmt_flat.c |
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/uaccess.h>
#include <linux/fs_struct.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/prefetch.h>
#include "mount.h"
#include "internal.h"
struct prepend_buffer {
char *buf;
int len;
};
#define DECLARE_BUFFER(__name, __buf, __len) \
struct prepend_buffer __name = {.buf = __buf + __len, .len = __len}
static char *extract_string(struct prepend_buffer *p)
{
if (likely(p->len >= 0))
return p->buf;
return ERR_PTR(-ENAMETOOLONG);
}
static bool prepend_char(struct prepend_buffer *p, unsigned char c)
{
if (likely(p->len > 0)) {
p->len--;
*--p->buf = c;
return true;
}
p->len = -1;
return false;
}
/*
* The source of the prepend data can be an optimistic load
* of a dentry name and length. And because we don't hold any
* locks, the length and the pointer to the name may not be
* in sync if a concurrent rename happens, and the kernel
* copy might fault as a result.
*
* The end result will correct itself when we check the
* rename sequence count, but we need to be able to handle
* the fault gracefully.
*/
static bool prepend_copy(void *dst, const void *src, int len)
{
if (unlikely(copy_from_kernel_nofault(dst, src, len))) {
memset(dst, 'x', len);
return false;
}
return true;
}
static bool prepend(struct prepend_buffer *p, const char *str, int namelen)
{
// Already overflowed?
if (p->len < 0)
return false;
// Will overflow?
if (p->len < namelen) {
// Fill as much as possible from the end of the name
str += namelen - p->len;
p->buf -= p->len;
prepend_copy(p->buf, str, p->len);
p->len = -1;
return false;
}
// Fits fully
p->len -= namelen;
p->buf -= namelen;
return prepend_copy(p->buf, str, namelen);
}
/**
* prepend_name - prepend a pathname in front of current buffer pointer
* @p: prepend buffer which contains buffer pointer and allocated length
* @name: name string and length qstr structure
*
* With RCU path tracing, it may race with d_move(). Use READ_ONCE() to
* make sure that either the old or the new name pointer and length are
* fetched. However, there may be mismatch between length and pointer.
* But since the length cannot be trusted, we need to copy the name very
* carefully when doing the prepend_copy(). It also prepends "/" at
* the beginning of the name. The sequence number check at the caller will
* retry it again when a d_move() does happen. So any garbage in the buffer
* due to mismatched pointer and length will be discarded.
*
* Load acquire is needed to make sure that we see the new name data even
* if we might get the length wrong.
*/
static bool prepend_name(struct prepend_buffer *p, const struct qstr *name)
{
const char *dname = smp_load_acquire(&name->name); /* ^^^ */
u32 dlen = READ_ONCE(name->len);
return prepend(p, dname, dlen) && prepend_char(p, '/');
}
static int __prepend_path(const struct dentry *dentry, const struct mount *mnt,
const struct path *root, struct prepend_buffer *p)
{
while (dentry != root->dentry || &mnt->mnt != root->mnt) {
const struct dentry *parent = READ_ONCE(dentry->d_parent);
if (dentry == mnt->mnt.mnt_root) {
struct mount *m = READ_ONCE(mnt->mnt_parent);
struct mnt_namespace *mnt_ns;
if (likely(mnt != m)) {
dentry = READ_ONCE(mnt->mnt_mountpoint);
mnt = m;
continue;
}
/* Global root */
mnt_ns = READ_ONCE(mnt->mnt_ns);
/* open-coded is_mounted() to use local mnt_ns */
if (!IS_ERR_OR_NULL(mnt_ns) && !is_anon_ns(mnt_ns))
return 1; // absolute root
else
return 2; // detached or not attached yet
}
if (unlikely(dentry == parent))
/* Escaped? */
return 3;
prefetch(parent);
if (!prepend_name(p, &dentry->d_name))
break;
dentry = parent;
}
return 0;
}
/**
* prepend_path - Prepend path string to a buffer
* @path: the dentry/vfsmount to report
* @root: root vfsmnt/dentry
* @p: prepend buffer which contains buffer pointer and allocated length
*
* The function will first try to write out the pathname without taking any
* lock other than the RCU read lock to make sure that dentries won't go away.
* It only checks the sequence number of the global rename_lock as any change
* in the dentry's d_seq will be preceded by changes in the rename_lock
* sequence number. If the sequence number had been changed, it will restart
* the whole pathname back-tracing sequence again by taking the rename_lock.
* In this case, there is no need to take the RCU read lock as the recursive
* parent pointer references will keep the dentry chain alive as long as no
* rename operation is performed.
*/
static int prepend_path(const struct path *path,
const struct path *root,
struct prepend_buffer *p)
{
unsigned seq, m_seq = 0;
struct prepend_buffer b;
int error;
rcu_read_lock();
restart_mnt:
read_seqbegin_or_lock(&mount_lock, &m_seq);
seq = 0;
rcu_read_lock();
restart:
b = *p;
read_seqbegin_or_lock(&rename_lock, &seq);
error = __prepend_path(path->dentry, real_mount(path->mnt), root, &b);
if (!(seq & 1))
rcu_read_unlock();
if (need_seqretry(&rename_lock, seq)) {
seq = 1;
goto restart;
}
done_seqretry(&rename_lock, seq);
if (!(m_seq & 1))
rcu_read_unlock();
if (need_seqretry(&mount_lock, m_seq)) {
m_seq = 1;
goto restart_mnt;
}
done_seqretry(&mount_lock, m_seq);
if (unlikely(error == 3))
b = *p;
if (b.len == p->len)
prepend_char(&b, '/');
*p = b;
return error;
}
/**
* __d_path - return the path of a dentry
* @path: the dentry/vfsmount to report
* @root: root vfsmnt/dentry
* @buf: buffer to return value in
* @buflen: buffer length
*
* Convert a dentry into an ASCII path name.
*
* Returns a pointer into the buffer or an error code if the
* path was too long.
*
* "buflen" should be positive.
*
* If the path is not reachable from the supplied root, return %NULL.
*/
char *__d_path(const struct path *path,
const struct path *root,
char *buf, int buflen)
{
DECLARE_BUFFER(b, buf, buflen);
prepend_char(&b, 0);
if (unlikely(prepend_path(path, root, &b) > 0))
return NULL;
return extract_string(&b);
}
char *d_absolute_path(const struct path *path,
char *buf, int buflen)
{
struct path root = {};
DECLARE_BUFFER(b, buf, buflen);
prepend_char(&b, 0);
if (unlikely(prepend_path(path, &root, &b) > 1))
return ERR_PTR(-EINVAL);
return extract_string(&b);
}
static void get_fs_root_rcu(struct fs_struct *fs, struct path *root)
{
unsigned seq;
do {
seq = read_seqcount_begin(&fs->seq);
*root = fs->root;
} while (read_seqcount_retry(&fs->seq, seq));
}
/**
* d_path - return the path of a dentry
* @path: path to report
* @buf: buffer to return value in
* @buflen: buffer length
*
* Convert a dentry into an ASCII path name. If the entry has been deleted
* the string " (deleted)" is appended. Note that this is ambiguous.
*
* Returns a pointer into the buffer or an error code if the path was
* too long. Note: Callers should use the returned pointer, not the passed
* in buffer, to use the name! The implementation often starts at an offset
* into the buffer, and may leave 0 bytes at the start.
*
* "buflen" should be positive.
*/
char *d_path(const struct path *path, char *buf, int buflen)
{
DECLARE_BUFFER(b, buf, buflen);
struct path root;
/*
* We have various synthetic filesystems that never get mounted. On
* these filesystems dentries are never used for lookup purposes, and
* thus don't need to be hashed. They also don't need a name until a
* user wants to identify the object in /proc/pid/fd/. The little hack
* below allows us to generate a name for these objects on demand:
*
* Some pseudo inodes are mountable. When they are mounted
* path->dentry == path->mnt->mnt_root. In that case don't call d_dname
* and instead have d_path return the mounted path.
*/
if (path->dentry->d_op && path->dentry->d_op->d_dname &&
(!IS_ROOT(path->dentry) || path->dentry != path->mnt->mnt_root))
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
rcu_read_lock();
get_fs_root_rcu(current->fs, &root);
if (unlikely(d_unlinked(path->dentry)))
prepend(&b, " (deleted)", 11);
else
prepend_char(&b, 0);
prepend_path(path, &root, &b);
rcu_read_unlock();
return extract_string(&b);
}
EXPORT_SYMBOL(d_path);
/*
* Helper function for dentry_operations.d_dname() members
*/
char *dynamic_dname(char *buffer, int buflen, const char *fmt, ...)
{
va_list args;
char temp[64];
int sz;
va_start(args, fmt);
sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1;
va_end(args);
if (sz > sizeof(temp) || sz > buflen)
return ERR_PTR(-ENAMETOOLONG);
buffer += buflen - sz;
return memcpy(buffer, temp, sz);
}
char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
{
DECLARE_BUFFER(b, buffer, buflen);
/* these dentries are never renamed, so d_lock is not needed */
prepend(&b, " (deleted)", 11);
prepend(&b, dentry->d_name.name, dentry->d_name.len);
prepend_char(&b, '/');
return extract_string(&b);
}
/*
* Write full pathname from the root of the filesystem into the buffer.
*/
static char *__dentry_path(const struct dentry *d, struct prepend_buffer *p)
{
const struct dentry *dentry;
struct prepend_buffer b;
int seq = 0;
rcu_read_lock();
restart:
dentry = d;
b = *p;
read_seqbegin_or_lock(&rename_lock, &seq);
while (!IS_ROOT(dentry)) {
const struct dentry *parent = dentry->d_parent;
prefetch(parent);
if (!prepend_name(&b, &dentry->d_name))
break;
dentry = parent;
}
if (!(seq & 1))
rcu_read_unlock();
if (need_seqretry(&rename_lock, seq)) {
seq = 1;
goto restart;
}
done_seqretry(&rename_lock, seq);
if (b.len == p->len)
prepend_char(&b, '/');
return extract_string(&b);
}
char *dentry_path_raw(const struct dentry *dentry, char *buf, int buflen)
{
DECLARE_BUFFER(b, buf, buflen);
prepend_char(&b, 0);
return __dentry_path(dentry, &b);
}
EXPORT_SYMBOL(dentry_path_raw);
char *dentry_path(const struct dentry *dentry, char *buf, int buflen)
{
DECLARE_BUFFER(b, buf, buflen);
if (unlikely(d_unlinked(dentry)))
prepend(&b, "//deleted", 10);
else
prepend_char(&b, 0);
return __dentry_path(dentry, &b);
}
static void get_fs_root_and_pwd_rcu(struct fs_struct *fs, struct path *root,
struct path *pwd)
{
unsigned seq;
do {
seq = read_seqcount_begin(&fs->seq);
*root = fs->root;
*pwd = fs->pwd;
} while (read_seqcount_retry(&fs->seq, seq));
}
/*
* NOTE! The user-level library version returns a
* character pointer. The kernel system call just
* returns the length of the buffer filled (which
* includes the ending '\0' character), or a negative
* error value. So libc would do something like
*
* char *getcwd(char * buf, size_t size)
* {
* int retval;
*
* retval = sys_getcwd(buf, size);
* if (retval >= 0)
* return buf;
* errno = -retval;
* return NULL;
* }
*/
SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
{
int error;
struct path pwd, root;
char *page = __getname();
if (!page)
return -ENOMEM;
rcu_read_lock();
get_fs_root_and_pwd_rcu(current->fs, &root, &pwd);
if (unlikely(d_unlinked(pwd.dentry))) {
rcu_read_unlock();
error = -ENOENT;
} else {
unsigned len;
DECLARE_BUFFER(b, page, PATH_MAX);
prepend_char(&b, 0);
if (unlikely(prepend_path(&pwd, &root, &b) > 0))
prepend(&b, "(unreachable)", 13);
rcu_read_unlock();
len = PATH_MAX - b.len;
if (unlikely(len > PATH_MAX))
error = -ENAMETOOLONG;
else if (unlikely(len > size))
error = -ERANGE;
else if (copy_to_user(buf, b.buf, len))
error = -EFAULT;
else
error = len;
}
__putname(page);
return error;
}
| linux-master | fs/d_path.c |
// SPDX-License-Identifier: GPL-2.0
/*
* fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
*
* In fact, that's a piece of procfs; it's *almost* isolated from
* the rest of fs/proc, but has rather close relationships with
* fs/namespace.c, thus here instead of fs/proc
*
*/
#include <linux/mnt_namespace.h>
#include <linux/nsproxy.h>
#include <linux/security.h>
#include <linux/fs_struct.h>
#include <linux/sched/task.h>
#include "proc/internal.h" /* only for get_proc_task() in ->open() */
#include "pnode.h"
#include "internal.h"
static __poll_t mounts_poll(struct file *file, poll_table *wait)
{
struct seq_file *m = file->private_data;
struct proc_mounts *p = m->private;
struct mnt_namespace *ns = p->ns;
__poll_t res = EPOLLIN | EPOLLRDNORM;
int event;
poll_wait(file, &p->ns->poll, wait);
event = READ_ONCE(ns->event);
if (m->poll_event != event) {
m->poll_event = event;
res |= EPOLLERR | EPOLLPRI;
}
return res;
}
struct proc_fs_opts {
int flag;
const char *str;
};
static int show_sb_opts(struct seq_file *m, struct super_block *sb)
{
static const struct proc_fs_opts fs_opts[] = {
{ SB_SYNCHRONOUS, ",sync" },
{ SB_DIRSYNC, ",dirsync" },
{ SB_MANDLOCK, ",mand" },
{ SB_LAZYTIME, ",lazytime" },
{ 0, NULL }
};
const struct proc_fs_opts *fs_infop;
for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) {
if (sb->s_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
}
return security_sb_show_options(m, sb);
}
static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
{
static const struct proc_fs_opts mnt_opts[] = {
{ MNT_NOSUID, ",nosuid" },
{ MNT_NODEV, ",nodev" },
{ MNT_NOEXEC, ",noexec" },
{ MNT_NOATIME, ",noatime" },
{ MNT_NODIRATIME, ",nodiratime" },
{ MNT_RELATIME, ",relatime" },
{ MNT_NOSYMFOLLOW, ",nosymfollow" },
{ 0, NULL }
};
const struct proc_fs_opts *fs_infop;
for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) {
if (mnt->mnt_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
}
if (is_idmapped_mnt(mnt))
seq_puts(m, ",idmapped");
}
static inline void mangle(struct seq_file *m, const char *s)
{
seq_escape(m, s, " \t\n\\#");
}
static void show_type(struct seq_file *m, struct super_block *sb)
{
mangle(m, sb->s_type->name);
if (sb->s_subtype) {
seq_putc(m, '.');
mangle(m, sb->s_subtype);
}
}
static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
{
struct proc_mounts *p = m->private;
struct mount *r = real_mount(mnt);
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
struct super_block *sb = mnt_path.dentry->d_sb;
int err;
if (sb->s_op->show_devname) {
err = sb->s_op->show_devname(m, mnt_path.dentry);
if (err)
goto out;
} else {
mangle(m, r->mnt_devname ? r->mnt_devname : "none");
}
seq_putc(m, ' ');
/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
if (err)
goto out;
seq_putc(m, ' ');
show_type(m, sb);
seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
err = show_sb_opts(m, sb);
if (err)
goto out;
show_mnt_opts(m, mnt);
if (sb->s_op->show_options)
err = sb->s_op->show_options(m, mnt_path.dentry);
seq_puts(m, " 0 0\n");
out:
return err;
}
static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
{
struct proc_mounts *p = m->private;
struct mount *r = real_mount(mnt);
struct super_block *sb = mnt->mnt_sb;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
int err;
seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
MAJOR(sb->s_dev), MINOR(sb->s_dev));
if (sb->s_op->show_path) {
err = sb->s_op->show_path(m, mnt->mnt_root);
if (err)
goto out;
} else {
seq_dentry(m, mnt->mnt_root, " \t\n\\");
}
seq_putc(m, ' ');
/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
if (err)
goto out;
seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
show_mnt_opts(m, mnt);
/* Tagged fields ("foo:X" or "bar") */
if (IS_MNT_SHARED(r))
seq_printf(m, " shared:%i", r->mnt_group_id);
if (IS_MNT_SLAVE(r)) {
int master = r->mnt_master->mnt_group_id;
int dom = get_dominating_id(r, &p->root);
seq_printf(m, " master:%i", master);
if (dom && dom != master)
seq_printf(m, " propagate_from:%i", dom);
}
if (IS_MNT_UNBINDABLE(r))
seq_puts(m, " unbindable");
/* Filesystem specific data */
seq_puts(m, " - ");
show_type(m, sb);
seq_putc(m, ' ');
if (sb->s_op->show_devname) {
err = sb->s_op->show_devname(m, mnt->mnt_root);
if (err)
goto out;
} else {
mangle(m, r->mnt_devname ? r->mnt_devname : "none");
}
seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
err = show_sb_opts(m, sb);
if (err)
goto out;
if (sb->s_op->show_options)
err = sb->s_op->show_options(m, mnt->mnt_root);
seq_putc(m, '\n');
out:
return err;
}
static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
{
struct proc_mounts *p = m->private;
struct mount *r = real_mount(mnt);
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
struct super_block *sb = mnt_path.dentry->d_sb;
int err;
/* device */
if (sb->s_op->show_devname) {
seq_puts(m, "device ");
err = sb->s_op->show_devname(m, mnt_path.dentry);
if (err)
goto out;
} else {
if (r->mnt_devname) {
seq_puts(m, "device ");
mangle(m, r->mnt_devname);
} else
seq_puts(m, "no device");
}
/* mount point */
seq_puts(m, " mounted on ");
/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
if (err)
goto out;
seq_putc(m, ' ');
/* file system type */
seq_puts(m, "with fstype ");
show_type(m, sb);
/* optional statistics */
if (sb->s_op->show_stats) {
seq_putc(m, ' ');
err = sb->s_op->show_stats(m, mnt_path.dentry);
}
seq_putc(m, '\n');
out:
return err;
}
static int mounts_open_common(struct inode *inode, struct file *file,
int (*show)(struct seq_file *, struct vfsmount *))
{
struct task_struct *task = get_proc_task(inode);
struct nsproxy *nsp;
struct mnt_namespace *ns = NULL;
struct path root;
struct proc_mounts *p;
struct seq_file *m;
int ret = -EINVAL;
if (!task)
goto err;
task_lock(task);
nsp = task->nsproxy;
if (!nsp || !nsp->mnt_ns) {
task_unlock(task);
put_task_struct(task);
goto err;
}
ns = nsp->mnt_ns;
get_mnt_ns(ns);
if (!task->fs) {
task_unlock(task);
put_task_struct(task);
ret = -ENOENT;
goto err_put_ns;
}
get_fs_root(task->fs, &root);
task_unlock(task);
put_task_struct(task);
ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
if (ret)
goto err_put_path;
m = file->private_data;
m->poll_event = ns->event;
p = m->private;
p->ns = ns;
p->root = root;
p->show = show;
INIT_LIST_HEAD(&p->cursor.mnt_list);
p->cursor.mnt.mnt_flags = MNT_CURSOR;
return 0;
err_put_path:
path_put(&root);
err_put_ns:
put_mnt_ns(ns);
err:
return ret;
}
static int mounts_release(struct inode *inode, struct file *file)
{
struct seq_file *m = file->private_data;
struct proc_mounts *p = m->private;
path_put(&p->root);
mnt_cursor_del(p->ns, &p->cursor);
put_mnt_ns(p->ns);
return seq_release_private(inode, file);
}
static int mounts_open(struct inode *inode, struct file *file)
{
return mounts_open_common(inode, file, show_vfsmnt);
}
static int mountinfo_open(struct inode *inode, struct file *file)
{
return mounts_open_common(inode, file, show_mountinfo);
}
static int mountstats_open(struct inode *inode, struct file *file)
{
return mounts_open_common(inode, file, show_vfsstat);
}
const struct file_operations proc_mounts_operations = {
.open = mounts_open,
.read_iter = seq_read_iter,
.splice_read = copy_splice_read,
.llseek = seq_lseek,
.release = mounts_release,
.poll = mounts_poll,
};
const struct file_operations proc_mountinfo_operations = {
.open = mountinfo_open,
.read_iter = seq_read_iter,
.splice_read = copy_splice_read,
.llseek = seq_lseek,
.release = mounts_release,
.poll = mounts_poll,
};
const struct file_operations proc_mountstats_operations = {
.open = mountstats_open,
.read_iter = seq_read_iter,
.splice_read = copy_splice_read,
.llseek = seq_lseek,
.release = mounts_release,
};
| linux-master | fs/proc_namespace.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This file contains the procedures for the handling of select and poll
*
* Created for Linux based loosely upon Mathius Lattner's minix
* patches by Peter MacDonald. Heavily edited by Linus.
*
* 4 February 1994
* COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
* flag set in its personality we do *not* modify the given timeout
* parameter to reflect time remaining.
*
* 24 January 2000
* Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
* of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
*/
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/sched/rt.h>
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/personality.h> /* for STICKY_TIMEOUTS */
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/fs.h>
#include <linux/rcupdate.h>
#include <linux/hrtimer.h>
#include <linux/freezer.h>
#include <net/busy_poll.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
/*
* Estimate expected accuracy in ns from a timeval.
*
* After quite a bit of churning around, we've settled on
* a simple thing of taking 0.1% of the timeout as the
* slack, with a cap of 100 msec.
* "nice" tasks get a 0.5% slack instead.
*
* Consider this comment an open invitation to come up with even
* better solutions..
*/
#define MAX_SLACK (100 * NSEC_PER_MSEC)
static long __estimate_accuracy(struct timespec64 *tv)
{
long slack;
int divfactor = 1000;
if (tv->tv_sec < 0)
return 0;
if (task_nice(current) > 0)
divfactor = divfactor / 5;
if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
return MAX_SLACK;
slack = tv->tv_nsec / divfactor;
slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
if (slack > MAX_SLACK)
return MAX_SLACK;
return slack;
}
u64 select_estimate_accuracy(struct timespec64 *tv)
{
u64 ret;
struct timespec64 now;
/*
* Realtime tasks get a slack of 0 for obvious reasons.
*/
if (rt_task(current))
return 0;
ktime_get_ts64(&now);
now = timespec64_sub(*tv, now);
ret = __estimate_accuracy(&now);
if (ret < current->timer_slack_ns)
return current->timer_slack_ns;
return ret;
}
struct poll_table_page {
struct poll_table_page * next;
struct poll_table_entry * entry;
struct poll_table_entry entries[];
};
#define POLL_TABLE_FULL(table) \
((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
/*
* Ok, Peter made a complicated, but straightforward multiple_wait() function.
* I have rewritten this, taking some shortcuts: This code may not be easy to
* follow, but it should be free of race-conditions, and it's practical. If you
* understand what I'm doing here, then you understand how the linux
* sleep/wakeup mechanism works.
*
* Two very simple procedures, poll_wait() and poll_freewait() make all the
* work. poll_wait() is an inline-function defined in <linux/poll.h>,
* as all select/poll functions have to call it to add an entry to the
* poll table.
*/
static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
poll_table *p);
void poll_initwait(struct poll_wqueues *pwq)
{
init_poll_funcptr(&pwq->pt, __pollwait);
pwq->polling_task = current;
pwq->triggered = 0;
pwq->error = 0;
pwq->table = NULL;
pwq->inline_index = 0;
}
EXPORT_SYMBOL(poll_initwait);
static void free_poll_entry(struct poll_table_entry *entry)
{
remove_wait_queue(entry->wait_address, &entry->wait);
fput(entry->filp);
}
void poll_freewait(struct poll_wqueues *pwq)
{
struct poll_table_page * p = pwq->table;
int i;
for (i = 0; i < pwq->inline_index; i++)
free_poll_entry(pwq->inline_entries + i);
while (p) {
struct poll_table_entry * entry;
struct poll_table_page *old;
entry = p->entry;
do {
entry--;
free_poll_entry(entry);
} while (entry > p->entries);
old = p;
p = p->next;
free_page((unsigned long) old);
}
}
EXPORT_SYMBOL(poll_freewait);
static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
{
struct poll_table_page *table = p->table;
if (p->inline_index < N_INLINE_POLL_ENTRIES)
return p->inline_entries + p->inline_index++;
if (!table || POLL_TABLE_FULL(table)) {
struct poll_table_page *new_table;
new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
if (!new_table) {
p->error = -ENOMEM;
return NULL;
}
new_table->entry = new_table->entries;
new_table->next = table;
p->table = new_table;
table = new_table;
}
return table->entry++;
}
static int __pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
struct poll_wqueues *pwq = wait->private;
DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
/*
* Although this function is called under waitqueue lock, LOCK
* doesn't imply write barrier and the users expect write
* barrier semantics on wakeup functions. The following
* smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
* and is paired with smp_store_mb() in poll_schedule_timeout.
*/
smp_wmb();
pwq->triggered = 1;
/*
* Perform the default wake up operation using a dummy
* waitqueue.
*
* TODO: This is hacky but there currently is no interface to
* pass in @sync. @sync is scheduled to be removed and once
* that happens, wake_up_process() can be used directly.
*/
return default_wake_function(&dummy_wait, mode, sync, key);
}
static int pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
struct poll_table_entry *entry;
entry = container_of(wait, struct poll_table_entry, wait);
if (key && !(key_to_poll(key) & entry->key))
return 0;
return __pollwake(wait, mode, sync, key);
}
/* Add a new entry */
static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
poll_table *p)
{
struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
struct poll_table_entry *entry = poll_get_entry(pwq);
if (!entry)
return;
entry->filp = get_file(filp);
entry->wait_address = wait_address;
entry->key = p->_key;
init_waitqueue_func_entry(&entry->wait, pollwake);
entry->wait.private = pwq;
add_wait_queue(wait_address, &entry->wait);
}
static int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
ktime_t *expires, unsigned long slack)
{
int rc = -EINTR;
set_current_state(state);
if (!pwq->triggered)
rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
__set_current_state(TASK_RUNNING);
/*
* Prepare for the next iteration.
*
* The following smp_store_mb() serves two purposes. First, it's
* the counterpart rmb of the wmb in pollwake() such that data
* written before wake up is always visible after wake up.
* Second, the full barrier guarantees that triggered clearing
* doesn't pass event check of the next iteration. Note that
* this problem doesn't exist for the first iteration as
* add_wait_queue() has full barrier semantics.
*/
smp_store_mb(pwq->triggered, 0);
return rc;
}
/**
* poll_select_set_timeout - helper function to setup the timeout value
* @to: pointer to timespec64 variable for the final timeout
* @sec: seconds (from user space)
* @nsec: nanoseconds (from user space)
*
* Note, we do not use a timespec for the user space value here, That
* way we can use the function for timeval and compat interfaces as well.
*
* Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
*/
int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec)
{
struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec};
if (!timespec64_valid(&ts))
return -EINVAL;
/* Optimize for the zero timeout value here */
if (!sec && !nsec) {
to->tv_sec = to->tv_nsec = 0;
} else {
ktime_get_ts64(to);
*to = timespec64_add_safe(*to, ts);
}
return 0;
}
enum poll_time_type {
PT_TIMEVAL = 0,
PT_OLD_TIMEVAL = 1,
PT_TIMESPEC = 2,
PT_OLD_TIMESPEC = 3,
};
static int poll_select_finish(struct timespec64 *end_time,
void __user *p,
enum poll_time_type pt_type, int ret)
{
struct timespec64 rts;
restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
if (!p)
return ret;
if (current->personality & STICKY_TIMEOUTS)
goto sticky;
/* No update for zero timeout */
if (!end_time->tv_sec && !end_time->tv_nsec)
return ret;
ktime_get_ts64(&rts);
rts = timespec64_sub(*end_time, rts);
if (rts.tv_sec < 0)
rts.tv_sec = rts.tv_nsec = 0;
switch (pt_type) {
case PT_TIMEVAL:
{
struct __kernel_old_timeval rtv;
if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
memset(&rtv, 0, sizeof(rtv));
rtv.tv_sec = rts.tv_sec;
rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
if (!copy_to_user(p, &rtv, sizeof(rtv)))
return ret;
}
break;
case PT_OLD_TIMEVAL:
{
struct old_timeval32 rtv;
rtv.tv_sec = rts.tv_sec;
rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
if (!copy_to_user(p, &rtv, sizeof(rtv)))
return ret;
}
break;
case PT_TIMESPEC:
if (!put_timespec64(&rts, p))
return ret;
break;
case PT_OLD_TIMESPEC:
if (!put_old_timespec32(&rts, p))
return ret;
break;
default:
BUG();
}
/*
* If an application puts its timeval in read-only memory, we
* don't want the Linux-specific update to the timeval to
* cause a fault after the select has completed
* successfully. However, because we're not updating the
* timeval, we can't restart the system call.
*/
sticky:
if (ret == -ERESTARTNOHAND)
ret = -EINTR;
return ret;
}
/*
* Scalable version of the fd_set.
*/
typedef struct {
unsigned long *in, *out, *ex;
unsigned long *res_in, *res_out, *res_ex;
} fd_set_bits;
/*
* How many longwords for "nr" bits?
*/
#define FDS_BITPERLONG (8*sizeof(long))
#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
/*
* Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
*/
static inline
int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
{
nr = FDS_BYTES(nr);
if (ufdset)
return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
memset(fdset, 0, nr);
return 0;
}
static inline unsigned long __must_check
set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
{
if (ufdset)
return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
return 0;
}
static inline
void zero_fd_set(unsigned long nr, unsigned long *fdset)
{
memset(fdset, 0, FDS_BYTES(nr));
}
#define FDS_IN(fds, n) (fds->in + n)
#define FDS_OUT(fds, n) (fds->out + n)
#define FDS_EX(fds, n) (fds->ex + n)
#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
static int max_select_fd(unsigned long n, fd_set_bits *fds)
{
unsigned long *open_fds;
unsigned long set;
int max;
struct fdtable *fdt;
/* handle last in-complete long-word first */
set = ~(~0UL << (n & (BITS_PER_LONG-1)));
n /= BITS_PER_LONG;
fdt = files_fdtable(current->files);
open_fds = fdt->open_fds + n;
max = 0;
if (set) {
set &= BITS(fds, n);
if (set) {
if (!(set & ~*open_fds))
goto get_max;
return -EBADF;
}
}
while (n) {
open_fds--;
n--;
set = BITS(fds, n);
if (!set)
continue;
if (set & ~*open_fds)
return -EBADF;
if (max)
continue;
get_max:
do {
max++;
set >>= 1;
} while (set);
max += n * BITS_PER_LONG;
}
return max;
}
#define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR |\
EPOLLNVAL)
#define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR |\
EPOLLNVAL)
#define POLLEX_SET (EPOLLPRI | EPOLLNVAL)
static inline void wait_key_set(poll_table *wait, unsigned long in,
unsigned long out, unsigned long bit,
__poll_t ll_flag)
{
wait->_key = POLLEX_SET | ll_flag;
if (in & bit)
wait->_key |= POLLIN_SET;
if (out & bit)
wait->_key |= POLLOUT_SET;
}
static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
{
ktime_t expire, *to = NULL;
struct poll_wqueues table;
poll_table *wait;
int retval, i, timed_out = 0;
u64 slack = 0;
__poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
unsigned long busy_start = 0;
rcu_read_lock();
retval = max_select_fd(n, fds);
rcu_read_unlock();
if (retval < 0)
return retval;
n = retval;
poll_initwait(&table);
wait = &table.pt;
if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
wait->_qproc = NULL;
timed_out = 1;
}
if (end_time && !timed_out)
slack = select_estimate_accuracy(end_time);
retval = 0;
for (;;) {
unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
bool can_busy_loop = false;
inp = fds->in; outp = fds->out; exp = fds->ex;
rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
unsigned long in, out, ex, all_bits, bit = 1, j;
unsigned long res_in = 0, res_out = 0, res_ex = 0;
__poll_t mask;
in = *inp++; out = *outp++; ex = *exp++;
all_bits = in | out | ex;
if (all_bits == 0) {
i += BITS_PER_LONG;
continue;
}
for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
struct fd f;
if (i >= n)
break;
if (!(bit & all_bits))
continue;
mask = EPOLLNVAL;
f = fdget(i);
if (f.file) {
wait_key_set(wait, in, out, bit,
busy_flag);
mask = vfs_poll(f.file, wait);
fdput(f);
}
if ((mask & POLLIN_SET) && (in & bit)) {
res_in |= bit;
retval++;
wait->_qproc = NULL;
}
if ((mask & POLLOUT_SET) && (out & bit)) {
res_out |= bit;
retval++;
wait->_qproc = NULL;
}
if ((mask & POLLEX_SET) && (ex & bit)) {
res_ex |= bit;
retval++;
wait->_qproc = NULL;
}
/* got something, stop busy polling */
if (retval) {
can_busy_loop = false;
busy_flag = 0;
/*
* only remember a returned
* POLL_BUSY_LOOP if we asked for it
*/
} else if (busy_flag & mask)
can_busy_loop = true;
}
if (res_in)
*rinp = res_in;
if (res_out)
*routp = res_out;
if (res_ex)
*rexp = res_ex;
cond_resched();
}
wait->_qproc = NULL;
if (retval || timed_out || signal_pending(current))
break;
if (table.error) {
retval = table.error;
break;
}
/* only if found POLL_BUSY_LOOP sockets && not out of time */
if (can_busy_loop && !need_resched()) {
if (!busy_start) {
busy_start = busy_loop_current_time();
continue;
}
if (!busy_loop_timeout(busy_start))
continue;
}
busy_flag = 0;
/*
* If this is the first loop and we have a timeout
* given, then we convert to ktime_t and set the to
* pointer to the expiry value.
*/
if (end_time && !to) {
expire = timespec64_to_ktime(*end_time);
to = &expire;
}
if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
to, slack))
timed_out = 1;
}
poll_freewait(&table);
return retval;
}
/*
* We can actually return ERESTARTSYS instead of EINTR, but I'd
* like to be certain this leads to no problems. So I return
* EINTR just for safety.
*
* Update: ERESTARTSYS breaks at least the xview clock binary, so
* I'm trying ERESTARTNOHAND which restart only when you want to.
*/
int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, struct timespec64 *end_time)
{
fd_set_bits fds;
void *bits;
int ret, max_fds;
size_t size, alloc_size;
struct fdtable *fdt;
/* Allocate small arguments on the stack to save memory and be faster */
long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
ret = -EINVAL;
if (n < 0)
goto out_nofds;
/* max_fds can increase, so grab it once to avoid race */
rcu_read_lock();
fdt = files_fdtable(current->files);
max_fds = fdt->max_fds;
rcu_read_unlock();
if (n > max_fds)
n = max_fds;
/*
* We need 6 bitmaps (in/out/ex for both incoming and outgoing),
* since we used fdset we need to allocate memory in units of
* long-words.
*/
size = FDS_BYTES(n);
bits = stack_fds;
if (size > sizeof(stack_fds) / 6) {
/* Not enough space in on-stack array; must use kmalloc */
ret = -ENOMEM;
if (size > (SIZE_MAX / 6))
goto out_nofds;
alloc_size = 6 * size;
bits = kvmalloc(alloc_size, GFP_KERNEL);
if (!bits)
goto out_nofds;
}
fds.in = bits;
fds.out = bits + size;
fds.ex = bits + 2*size;
fds.res_in = bits + 3*size;
fds.res_out = bits + 4*size;
fds.res_ex = bits + 5*size;
if ((ret = get_fd_set(n, inp, fds.in)) ||
(ret = get_fd_set(n, outp, fds.out)) ||
(ret = get_fd_set(n, exp, fds.ex)))
goto out;
zero_fd_set(n, fds.res_in);
zero_fd_set(n, fds.res_out);
zero_fd_set(n, fds.res_ex);
ret = do_select(n, &fds, end_time);
if (ret < 0)
goto out;
if (!ret) {
ret = -ERESTARTNOHAND;
if (signal_pending(current))
goto out;
ret = 0;
}
if (set_fd_set(n, inp, fds.res_in) ||
set_fd_set(n, outp, fds.res_out) ||
set_fd_set(n, exp, fds.res_ex))
ret = -EFAULT;
out:
if (bits != stack_fds)
kvfree(bits);
out_nofds:
return ret;
}
static int kern_select(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, struct __kernel_old_timeval __user *tvp)
{
struct timespec64 end_time, *to = NULL;
struct __kernel_old_timeval tv;
int ret;
if (tvp) {
if (copy_from_user(&tv, tvp, sizeof(tv)))
return -EFAULT;
to = &end_time;
if (poll_select_set_timeout(to,
tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
(tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
return -EINVAL;
}
ret = core_sys_select(n, inp, outp, exp, to);
return poll_select_finish(&end_time, tvp, PT_TIMEVAL, ret);
}
SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
fd_set __user *, exp, struct __kernel_old_timeval __user *, tvp)
{
return kern_select(n, inp, outp, exp, tvp);
}
static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
fd_set __user *exp, void __user *tsp,
const sigset_t __user *sigmask, size_t sigsetsize,
enum poll_time_type type)
{
struct timespec64 ts, end_time, *to = NULL;
int ret;
if (tsp) {
switch (type) {
case PT_TIMESPEC:
if (get_timespec64(&ts, tsp))
return -EFAULT;
break;
case PT_OLD_TIMESPEC:
if (get_old_timespec32(&ts, tsp))
return -EFAULT;
break;
default:
BUG();
}
to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
ret = set_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = core_sys_select(n, inp, outp, exp, to);
return poll_select_finish(&end_time, tsp, type, ret);
}
/*
* Most architectures can't handle 7-argument syscalls. So we provide a
* 6-argument version where the sixth argument is a pointer to a structure
* which has a pointer to the sigset_t itself followed by a size_t containing
* the sigset size.
*/
struct sigset_argpack {
sigset_t __user *p;
size_t size;
};
static inline int get_sigset_argpack(struct sigset_argpack *to,
struct sigset_argpack __user *from)
{
// the path is hot enough for overhead of copy_from_user() to matter
if (from) {
if (!user_read_access_begin(from, sizeof(*from)))
return -EFAULT;
unsafe_get_user(to->p, &from->p, Efault);
unsafe_get_user(to->size, &from->size, Efault);
user_read_access_end();
}
return 0;
Efault:
user_access_end();
return -EFAULT;
}
SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
fd_set __user *, exp, struct __kernel_timespec __user *, tsp,
void __user *, sig)
{
struct sigset_argpack x = {NULL, 0};
if (get_sigset_argpack(&x, sig))
return -EFAULT;
return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_TIMESPEC);
}
#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
SYSCALL_DEFINE6(pselect6_time32, int, n, fd_set __user *, inp, fd_set __user *, outp,
fd_set __user *, exp, struct old_timespec32 __user *, tsp,
void __user *, sig)
{
struct sigset_argpack x = {NULL, 0};
if (get_sigset_argpack(&x, sig))
return -EFAULT;
return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_OLD_TIMESPEC);
}
#endif
#ifdef __ARCH_WANT_SYS_OLD_SELECT
struct sel_arg_struct {
unsigned long n;
fd_set __user *inp, *outp, *exp;
struct __kernel_old_timeval __user *tvp;
};
SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
{
struct sel_arg_struct a;
if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
return kern_select(a.n, a.inp, a.outp, a.exp, a.tvp);
}
#endif
struct poll_list {
struct poll_list *next;
int len;
struct pollfd entries[];
};
#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
/*
* Fish for pollable events on the pollfd->fd file descriptor. We're only
* interested in events matching the pollfd->events mask, and the result
* matching that mask is both recorded in pollfd->revents and returned. The
* pwait poll_table will be used by the fd-provided poll handler for waiting,
* if pwait->_qproc is non-NULL.
*/
static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait,
bool *can_busy_poll,
__poll_t busy_flag)
{
int fd = pollfd->fd;
__poll_t mask = 0, filter;
struct fd f;
if (fd < 0)
goto out;
mask = EPOLLNVAL;
f = fdget(fd);
if (!f.file)
goto out;
/* userland u16 ->events contains POLL... bitmap */
filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP;
pwait->_key = filter | busy_flag;
mask = vfs_poll(f.file, pwait);
if (mask & busy_flag)
*can_busy_poll = true;
mask &= filter; /* Mask out unneeded events. */
fdput(f);
out:
/* ... and so does ->revents */
pollfd->revents = mangle_poll(mask);
return mask;
}
static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
struct timespec64 *end_time)
{
poll_table* pt = &wait->pt;
ktime_t expire, *to = NULL;
int timed_out = 0, count = 0;
u64 slack = 0;
__poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
unsigned long busy_start = 0;
/* Optimise the no-wait case */
if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
pt->_qproc = NULL;
timed_out = 1;
}
if (end_time && !timed_out)
slack = select_estimate_accuracy(end_time);
for (;;) {
struct poll_list *walk;
bool can_busy_loop = false;
for (walk = list; walk != NULL; walk = walk->next) {
struct pollfd * pfd, * pfd_end;
pfd = walk->entries;
pfd_end = pfd + walk->len;
for (; pfd != pfd_end; pfd++) {
/*
* Fish for events. If we found one, record it
* and kill poll_table->_qproc, so we don't
* needlessly register any other waiters after
* this. They'll get immediately deregistered
* when we break out and return.
*/
if (do_pollfd(pfd, pt, &can_busy_loop,
busy_flag)) {
count++;
pt->_qproc = NULL;
/* found something, stop busy polling */
busy_flag = 0;
can_busy_loop = false;
}
}
}
/*
* All waiters have already been registered, so don't provide
* a poll_table->_qproc to them on the next loop iteration.
*/
pt->_qproc = NULL;
if (!count) {
count = wait->error;
if (signal_pending(current))
count = -ERESTARTNOHAND;
}
if (count || timed_out)
break;
/* only if found POLL_BUSY_LOOP sockets && not out of time */
if (can_busy_loop && !need_resched()) {
if (!busy_start) {
busy_start = busy_loop_current_time();
continue;
}
if (!busy_loop_timeout(busy_start))
continue;
}
busy_flag = 0;
/*
* If this is the first loop and we have a timeout
* given, then we convert to ktime_t and set the to
* pointer to the expiry value.
*/
if (end_time && !to) {
expire = timespec64_to_ktime(*end_time);
to = &expire;
}
if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
timed_out = 1;
}
return count;
}
#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
sizeof(struct pollfd))
static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
struct timespec64 *end_time)
{
struct poll_wqueues table;
int err = -EFAULT, fdcount, len;
/* Allocate small arguments on the stack to save memory and be
faster - use long to make sure the buffer is aligned properly
on 64 bit archs to avoid unaligned access */
long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
struct poll_list *const head = (struct poll_list *)stack_pps;
struct poll_list *walk = head;
unsigned long todo = nfds;
if (nfds > rlimit(RLIMIT_NOFILE))
return -EINVAL;
len = min_t(unsigned int, nfds, N_STACK_PPS);
for (;;) {
walk->next = NULL;
walk->len = len;
if (!len)
break;
if (copy_from_user(walk->entries, ufds + nfds-todo,
sizeof(struct pollfd) * walk->len))
goto out_fds;
todo -= walk->len;
if (!todo)
break;
len = min(todo, POLLFD_PER_PAGE);
walk = walk->next = kmalloc(struct_size(walk, entries, len),
GFP_KERNEL);
if (!walk) {
err = -ENOMEM;
goto out_fds;
}
}
poll_initwait(&table);
fdcount = do_poll(head, &table, end_time);
poll_freewait(&table);
if (!user_write_access_begin(ufds, nfds * sizeof(*ufds)))
goto out_fds;
for (walk = head; walk; walk = walk->next) {
struct pollfd *fds = walk->entries;
int j;
for (j = walk->len; j; fds++, ufds++, j--)
unsafe_put_user(fds->revents, &ufds->revents, Efault);
}
user_write_access_end();
err = fdcount;
out_fds:
walk = head->next;
while (walk) {
struct poll_list *pos = walk;
walk = walk->next;
kfree(pos);
}
return err;
Efault:
user_write_access_end();
err = -EFAULT;
goto out_fds;
}
static long do_restart_poll(struct restart_block *restart_block)
{
struct pollfd __user *ufds = restart_block->poll.ufds;
int nfds = restart_block->poll.nfds;
struct timespec64 *to = NULL, end_time;
int ret;
if (restart_block->poll.has_timeout) {
end_time.tv_sec = restart_block->poll.tv_sec;
end_time.tv_nsec = restart_block->poll.tv_nsec;
to = &end_time;
}
ret = do_sys_poll(ufds, nfds, to);
if (ret == -ERESTARTNOHAND)
ret = set_restart_fn(restart_block, do_restart_poll);
return ret;
}
SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
int, timeout_msecs)
{
struct timespec64 end_time, *to = NULL;
int ret;
if (timeout_msecs >= 0) {
to = &end_time;
poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
}
ret = do_sys_poll(ufds, nfds, to);
if (ret == -ERESTARTNOHAND) {
struct restart_block *restart_block;
restart_block = ¤t->restart_block;
restart_block->poll.ufds = ufds;
restart_block->poll.nfds = nfds;
if (timeout_msecs >= 0) {
restart_block->poll.tv_sec = end_time.tv_sec;
restart_block->poll.tv_nsec = end_time.tv_nsec;
restart_block->poll.has_timeout = 1;
} else
restart_block->poll.has_timeout = 0;
ret = set_restart_fn(restart_block, do_restart_poll);
}
return ret;
}
SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
struct __kernel_timespec __user *, tsp, const sigset_t __user *, sigmask,
size_t, sigsetsize)
{
struct timespec64 ts, end_time, *to = NULL;
int ret;
if (tsp) {
if (get_timespec64(&ts, tsp))
return -EFAULT;
to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
ret = set_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret);
}
#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds,
struct old_timespec32 __user *, tsp, const sigset_t __user *, sigmask,
size_t, sigsetsize)
{
struct timespec64 ts, end_time, *to = NULL;
int ret;
if (tsp) {
if (get_old_timespec32(&ts, tsp))
return -EFAULT;
to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
ret = set_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret);
}
#endif
#ifdef CONFIG_COMPAT
#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))
/*
* Ooo, nasty. We need here to frob 32-bit unsigned longs to
* 64-bit unsigned longs.
*/
static
int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
unsigned long *fdset)
{
if (ufdset) {
return compat_get_bitmap(fdset, ufdset, nr);
} else {
zero_fd_set(nr, fdset);
return 0;
}
}
static
int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
unsigned long *fdset)
{
if (!ufdset)
return 0;
return compat_put_bitmap(ufdset, fdset, nr);
}
/*
* This is a virtual copy of sys_select from fs/select.c and probably
* should be compared to it from time to time
*/
/*
* We can actually return ERESTARTSYS instead of EINTR, but I'd
* like to be certain this leads to no problems. So I return
* EINTR just for safety.
*
* Update: ERESTARTSYS breaks at least the xview clock binary, so
* I'm trying ERESTARTNOHAND which restart only when you want to.
*/
static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
struct timespec64 *end_time)
{
fd_set_bits fds;
void *bits;
int size, max_fds, ret = -EINVAL;
struct fdtable *fdt;
long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
if (n < 0)
goto out_nofds;
/* max_fds can increase, so grab it once to avoid race */
rcu_read_lock();
fdt = files_fdtable(current->files);
max_fds = fdt->max_fds;
rcu_read_unlock();
if (n > max_fds)
n = max_fds;
/*
* We need 6 bitmaps (in/out/ex for both incoming and outgoing),
* since we used fdset we need to allocate memory in units of
* long-words.
*/
size = FDS_BYTES(n);
bits = stack_fds;
if (size > sizeof(stack_fds) / 6) {
bits = kmalloc_array(6, size, GFP_KERNEL);
ret = -ENOMEM;
if (!bits)
goto out_nofds;
}
fds.in = (unsigned long *) bits;
fds.out = (unsigned long *) (bits + size);
fds.ex = (unsigned long *) (bits + 2*size);
fds.res_in = (unsigned long *) (bits + 3*size);
fds.res_out = (unsigned long *) (bits + 4*size);
fds.res_ex = (unsigned long *) (bits + 5*size);
if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
(ret = compat_get_fd_set(n, outp, fds.out)) ||
(ret = compat_get_fd_set(n, exp, fds.ex)))
goto out;
zero_fd_set(n, fds.res_in);
zero_fd_set(n, fds.res_out);
zero_fd_set(n, fds.res_ex);
ret = do_select(n, &fds, end_time);
if (ret < 0)
goto out;
if (!ret) {
ret = -ERESTARTNOHAND;
if (signal_pending(current))
goto out;
ret = 0;
}
if (compat_set_fd_set(n, inp, fds.res_in) ||
compat_set_fd_set(n, outp, fds.res_out) ||
compat_set_fd_set(n, exp, fds.res_ex))
ret = -EFAULT;
out:
if (bits != stack_fds)
kfree(bits);
out_nofds:
return ret;
}
static int do_compat_select(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
struct old_timeval32 __user *tvp)
{
struct timespec64 end_time, *to = NULL;
struct old_timeval32 tv;
int ret;
if (tvp) {
if (copy_from_user(&tv, tvp, sizeof(tv)))
return -EFAULT;
to = &end_time;
if (poll_select_set_timeout(to,
tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
(tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
return -EINVAL;
}
ret = compat_core_sys_select(n, inp, outp, exp, to);
return poll_select_finish(&end_time, tvp, PT_OLD_TIMEVAL, ret);
}
COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct old_timeval32 __user *, tvp)
{
return do_compat_select(n, inp, outp, exp, tvp);
}
struct compat_sel_arg_struct {
compat_ulong_t n;
compat_uptr_t inp;
compat_uptr_t outp;
compat_uptr_t exp;
compat_uptr_t tvp;
};
COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
{
struct compat_sel_arg_struct a;
if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
return do_compat_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
compat_ptr(a.exp), compat_ptr(a.tvp));
}
static long do_compat_pselect(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
void __user *tsp, compat_sigset_t __user *sigmask,
compat_size_t sigsetsize, enum poll_time_type type)
{
struct timespec64 ts, end_time, *to = NULL;
int ret;
if (tsp) {
switch (type) {
case PT_OLD_TIMESPEC:
if (get_old_timespec32(&ts, tsp))
return -EFAULT;
break;
case PT_TIMESPEC:
if (get_timespec64(&ts, tsp))
return -EFAULT;
break;
default:
BUG();
}
to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
ret = set_compat_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = compat_core_sys_select(n, inp, outp, exp, to);
return poll_select_finish(&end_time, tsp, type, ret);
}
struct compat_sigset_argpack {
compat_uptr_t p;
compat_size_t size;
};
static inline int get_compat_sigset_argpack(struct compat_sigset_argpack *to,
struct compat_sigset_argpack __user *from)
{
if (from) {
if (!user_read_access_begin(from, sizeof(*from)))
return -EFAULT;
unsafe_get_user(to->p, &from->p, Efault);
unsafe_get_user(to->size, &from->size, Efault);
user_read_access_end();
}
return 0;
Efault:
user_access_end();
return -EFAULT;
}
COMPAT_SYSCALL_DEFINE6(pselect6_time64, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct __kernel_timespec __user *, tsp, void __user *, sig)
{
struct compat_sigset_argpack x = {0, 0};
if (get_compat_sigset_argpack(&x, sig))
return -EFAULT;
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p),
x.size, PT_TIMESPEC);
}
#if defined(CONFIG_COMPAT_32BIT_TIME)
COMPAT_SYSCALL_DEFINE6(pselect6_time32, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct old_timespec32 __user *, tsp, void __user *, sig)
{
struct compat_sigset_argpack x = {0, 0};
if (get_compat_sigset_argpack(&x, sig))
return -EFAULT;
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p),
x.size, PT_OLD_TIMESPEC);
}
#endif
#if defined(CONFIG_COMPAT_32BIT_TIME)
COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds,
unsigned int, nfds, struct old_timespec32 __user *, tsp,
const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
{
struct timespec64 ts, end_time, *to = NULL;
int ret;
if (tsp) {
if (get_old_timespec32(&ts, tsp))
return -EFAULT;
to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
ret = set_compat_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret);
}
#endif
/* New compat syscall for 64 bit time_t*/
COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds,
unsigned int, nfds, struct __kernel_timespec __user *, tsp,
const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
{
struct timespec64 ts, end_time, *to = NULL;
int ret;
if (tsp) {
if (get_timespec64(&ts, tsp))
return -EFAULT;
to = &end_time;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
return -EINVAL;
}
ret = set_compat_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret);
}
#endif
| linux-master | fs/select.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* binfmt_elf_fdpic.c: FDPIC ELF binary format
*
* Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
* Derived from binfmt_elf.c
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/cputime.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/security.h>
#include <linux/highmem.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/init.h>
#include <linux/elf.h>
#include <linux/elf-fdpic.h>
#include <linux/elfcore.h>
#include <linux/coredump.h>
#include <linux/dax.h>
#include <linux/regset.h>
#include <linux/uaccess.h>
#include <asm/param.h>
typedef char *elf_caddr_t;
#if 0
#define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdebug(fmt, ...) do {} while(0)
#endif
#if 0
#define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdcore(fmt, ...) do {} while(0)
#endif
MODULE_LICENSE("GPL");
static int load_elf_fdpic_binary(struct linux_binprm *);
static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
struct mm_struct *, const char *);
static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
struct elf_fdpic_params *,
struct elf_fdpic_params *);
#ifndef CONFIG_MMU
static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
struct file *,
struct mm_struct *);
#endif
static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
struct file *, struct mm_struct *);
#ifdef CONFIG_ELF_CORE
static int elf_fdpic_core_dump(struct coredump_params *cprm);
#endif
static struct linux_binfmt elf_fdpic_format = {
.module = THIS_MODULE,
.load_binary = load_elf_fdpic_binary,
#ifdef CONFIG_ELF_CORE
.core_dump = elf_fdpic_core_dump,
.min_coredump = ELF_EXEC_PAGESIZE,
#endif
};
static int __init init_elf_fdpic_binfmt(void)
{
register_binfmt(&elf_fdpic_format);
return 0;
}
static void __exit exit_elf_fdpic_binfmt(void)
{
unregister_binfmt(&elf_fdpic_format);
}
core_initcall(init_elf_fdpic_binfmt);
module_exit(exit_elf_fdpic_binfmt);
static int is_elf(struct elfhdr *hdr, struct file *file)
{
if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
return 0;
if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
return 0;
if (!elf_check_arch(hdr))
return 0;
if (!file->f_op->mmap)
return 0;
return 1;
}
#ifndef elf_check_fdpic
#define elf_check_fdpic(x) 0
#endif
#ifndef elf_check_const_displacement
#define elf_check_const_displacement(x) 0
#endif
static int is_constdisp(struct elfhdr *hdr)
{
if (!elf_check_fdpic(hdr))
return 1;
if (elf_check_const_displacement(hdr))
return 1;
return 0;
}
/*****************************************************************************/
/*
* read the program headers table into memory
*/
static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
struct file *file)
{
struct elf_phdr *phdr;
unsigned long size;
int retval, loop;
loff_t pos = params->hdr.e_phoff;
if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
return -ENOMEM;
if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
return -ENOMEM;
size = params->hdr.e_phnum * sizeof(struct elf_phdr);
params->phdrs = kmalloc(size, GFP_KERNEL);
if (!params->phdrs)
return -ENOMEM;
retval = kernel_read(file, params->phdrs, size, &pos);
if (unlikely(retval != size))
return retval < 0 ? retval : -ENOEXEC;
/* determine stack size for this binary */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (phdr->p_type != PT_GNU_STACK)
continue;
if (phdr->p_flags & PF_X)
params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
else
params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
params->stack_size = phdr->p_memsz;
break;
}
return 0;
}
/*****************************************************************************/
/*
* load an fdpic binary into various bits of memory
*/
static int load_elf_fdpic_binary(struct linux_binprm *bprm)
{
struct elf_fdpic_params exec_params, interp_params;
struct pt_regs *regs = current_pt_regs();
struct elf_phdr *phdr;
unsigned long stack_size, entryaddr;
#ifdef ELF_FDPIC_PLAT_INIT
unsigned long dynaddr;
#endif
#ifndef CONFIG_MMU
unsigned long stack_prot;
#endif
struct file *interpreter = NULL; /* to shut gcc up */
char *interpreter_name = NULL;
int executable_stack;
int retval, i;
loff_t pos;
kdebug("____ LOAD %d ____", current->pid);
memset(&exec_params, 0, sizeof(exec_params));
memset(&interp_params, 0, sizeof(interp_params));
exec_params.hdr = *(struct elfhdr *) bprm->buf;
exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
/* check that this is a binary we know how to deal with */
retval = -ENOEXEC;
if (!is_elf(&exec_params.hdr, bprm->file))
goto error;
if (!elf_check_fdpic(&exec_params.hdr)) {
#ifdef CONFIG_MMU
/* binfmt_elf handles non-fdpic elf except on nommu */
goto error;
#else
/* nommu can only load ET_DYN (PIE) ELF */
if (exec_params.hdr.e_type != ET_DYN)
goto error;
#endif
}
/* read the program header table */
retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
if (retval < 0)
goto error;
/* scan for a program header that specifies an interpreter */
phdr = exec_params.phdrs;
for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
switch (phdr->p_type) {
case PT_INTERP:
retval = -ENOMEM;
if (phdr->p_filesz > PATH_MAX)
goto error;
retval = -ENOENT;
if (phdr->p_filesz < 2)
goto error;
/* read the name of the interpreter into memory */
interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
if (!interpreter_name)
goto error;
pos = phdr->p_offset;
retval = kernel_read(bprm->file, interpreter_name,
phdr->p_filesz, &pos);
if (unlikely(retval != phdr->p_filesz)) {
if (retval >= 0)
retval = -ENOEXEC;
goto error;
}
retval = -ENOENT;
if (interpreter_name[phdr->p_filesz - 1] != '\0')
goto error;
kdebug("Using ELF interpreter %s", interpreter_name);
/* replace the program with the interpreter */
interpreter = open_exec(interpreter_name);
retval = PTR_ERR(interpreter);
if (IS_ERR(interpreter)) {
interpreter = NULL;
goto error;
}
/*
* If the binary is not readable then enforce
* mm->dumpable = 0 regardless of the interpreter's
* permissions.
*/
would_dump(bprm, interpreter);
pos = 0;
retval = kernel_read(interpreter, bprm->buf,
BINPRM_BUF_SIZE, &pos);
if (unlikely(retval != BINPRM_BUF_SIZE)) {
if (retval >= 0)
retval = -ENOEXEC;
goto error;
}
interp_params.hdr = *((struct elfhdr *) bprm->buf);
break;
case PT_LOAD:
#ifdef CONFIG_MMU
if (exec_params.load_addr == 0)
exec_params.load_addr = phdr->p_vaddr;
#endif
break;
}
}
if (is_constdisp(&exec_params.hdr))
exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
/* perform insanity checks on the interpreter */
if (interpreter_name) {
retval = -ELIBBAD;
if (!is_elf(&interp_params.hdr, interpreter))
goto error;
interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
/* read the interpreter's program header table */
retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
if (retval < 0)
goto error;
}
stack_size = exec_params.stack_size;
if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
executable_stack = EXSTACK_ENABLE_X;
else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
executable_stack = EXSTACK_DISABLE_X;
else
executable_stack = EXSTACK_DEFAULT;
if (stack_size == 0) {
stack_size = interp_params.stack_size;
if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
executable_stack = EXSTACK_ENABLE_X;
else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
executable_stack = EXSTACK_DISABLE_X;
else
executable_stack = EXSTACK_DEFAULT;
}
retval = -ENOEXEC;
if (stack_size == 0)
stack_size = 131072UL; /* same as exec.c's default commit */
if (is_constdisp(&interp_params.hdr))
interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
/* flush all traces of the currently running executable */
retval = begin_new_exec(bprm);
if (retval)
goto error;
/* there's now no turning back... the old userspace image is dead,
* defunct, deceased, etc.
*/
if (elf_check_fdpic(&exec_params.hdr))
set_personality(PER_LINUX_FDPIC);
else
set_personality(PER_LINUX);
if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
current->personality |= READ_IMPLIES_EXEC;
setup_new_exec(bprm);
set_binfmt(&elf_fdpic_format);
current->mm->start_code = 0;
current->mm->end_code = 0;
current->mm->start_stack = 0;
current->mm->start_data = 0;
current->mm->end_data = 0;
current->mm->context.exec_fdpic_loadmap = 0;
current->mm->context.interp_fdpic_loadmap = 0;
#ifdef CONFIG_MMU
elf_fdpic_arch_lay_out_mm(&exec_params,
&interp_params,
¤t->mm->start_stack,
¤t->mm->start_brk);
retval = setup_arg_pages(bprm, current->mm->start_stack,
executable_stack);
if (retval < 0)
goto error;
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
retval = arch_setup_additional_pages(bprm, !!interpreter_name);
if (retval < 0)
goto error;
#endif
#endif
/* load the executable and interpreter into memory */
retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
"executable");
if (retval < 0)
goto error;
if (interpreter_name) {
retval = elf_fdpic_map_file(&interp_params, interpreter,
current->mm, "interpreter");
if (retval < 0) {
printk(KERN_ERR "Unable to load interpreter\n");
goto error;
}
allow_write_access(interpreter);
fput(interpreter);
interpreter = NULL;
}
#ifdef CONFIG_MMU
if (!current->mm->start_brk)
current->mm->start_brk = current->mm->end_data;
current->mm->brk = current->mm->start_brk =
PAGE_ALIGN(current->mm->start_brk);
#else
/* create a stack area and zero-size brk area */
stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
if (stack_size < PAGE_SIZE * 2)
stack_size = PAGE_SIZE * 2;
stack_prot = PROT_READ | PROT_WRITE;
if (executable_stack == EXSTACK_ENABLE_X ||
(executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
stack_prot |= PROT_EXEC;
current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
MAP_PRIVATE | MAP_ANONYMOUS |
MAP_UNINITIALIZED | MAP_GROWSDOWN,
0);
if (IS_ERR_VALUE(current->mm->start_brk)) {
retval = current->mm->start_brk;
current->mm->start_brk = 0;
goto error;
}
current->mm->brk = current->mm->start_brk;
current->mm->context.end_brk = current->mm->start_brk;
current->mm->start_stack = current->mm->start_brk + stack_size;
#endif
retval = create_elf_fdpic_tables(bprm, current->mm, &exec_params,
&interp_params);
if (retval < 0)
goto error;
kdebug("- start_code %lx", current->mm->start_code);
kdebug("- end_code %lx", current->mm->end_code);
kdebug("- start_data %lx", current->mm->start_data);
kdebug("- end_data %lx", current->mm->end_data);
kdebug("- start_brk %lx", current->mm->start_brk);
kdebug("- brk %lx", current->mm->brk);
kdebug("- start_stack %lx", current->mm->start_stack);
#ifdef ELF_FDPIC_PLAT_INIT
/*
* The ABI may specify that certain registers be set up in special
* ways (on i386 %edx is the address of a DT_FINI function, for
* example. This macro performs whatever initialization to
* the regs structure is required.
*/
dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
dynaddr);
#endif
finalize_exec(bprm);
/* everything is now ready... get the userspace context ready to roll */
entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
start_thread(regs, entryaddr, current->mm->start_stack);
retval = 0;
error:
if (interpreter) {
allow_write_access(interpreter);
fput(interpreter);
}
kfree(interpreter_name);
kfree(exec_params.phdrs);
kfree(exec_params.loadmap);
kfree(interp_params.phdrs);
kfree(interp_params.loadmap);
return retval;
}
/*****************************************************************************/
#ifndef ELF_BASE_PLATFORM
/*
* AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
* If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
* will be copied to the user stack in the same manner as AT_PLATFORM.
*/
#define ELF_BASE_PLATFORM NULL
#endif
/*
* present useful information to the program by shovelling it onto the new
* process's stack
*/
static int create_elf_fdpic_tables(struct linux_binprm *bprm,
struct mm_struct *mm,
struct elf_fdpic_params *exec_params,
struct elf_fdpic_params *interp_params)
{
const struct cred *cred = current_cred();
unsigned long sp, csp, nitems;
elf_caddr_t __user *argv, *envp;
size_t platform_len = 0, len;
char *k_platform, *k_base_platform;
char __user *u_platform, *u_base_platform, *p;
int loop;
int nr; /* reset for each csp adjustment */
unsigned long flags = 0;
#ifdef CONFIG_MMU
/* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
* by the processes running on the same package. One thing we can do is
* to shuffle the initial stack for them, so we give the architecture
* an opportunity to do so here.
*/
sp = arch_align_stack(bprm->p);
#else
sp = mm->start_stack;
/* stack the program arguments and environment */
if (transfer_args_to_stack(bprm, &sp) < 0)
return -EFAULT;
sp &= ~15;
#endif
/*
* If this architecture has a platform capability string, copy it
* to userspace. In some cases (Sparc), this info is impossible
* for userspace to get any other way, in others (i386) it is
* merely difficult.
*/
k_platform = ELF_PLATFORM;
u_platform = NULL;
if (k_platform) {
platform_len = strlen(k_platform) + 1;
sp -= platform_len;
u_platform = (char __user *) sp;
if (copy_to_user(u_platform, k_platform, platform_len) != 0)
return -EFAULT;
}
/*
* If this architecture has a "base" platform capability
* string, copy it to userspace.
*/
k_base_platform = ELF_BASE_PLATFORM;
u_base_platform = NULL;
if (k_base_platform) {
platform_len = strlen(k_base_platform) + 1;
sp -= platform_len;
u_base_platform = (char __user *) sp;
if (copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
return -EFAULT;
}
sp &= ~7UL;
/* stack the load map(s) */
len = sizeof(struct elf_fdpic_loadmap);
len += sizeof(struct elf_fdpic_loadseg) * exec_params->loadmap->nsegs;
sp = (sp - len) & ~7UL;
exec_params->map_addr = sp;
if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
return -EFAULT;
current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
if (interp_params->loadmap) {
len = sizeof(struct elf_fdpic_loadmap);
len += sizeof(struct elf_fdpic_loadseg) *
interp_params->loadmap->nsegs;
sp = (sp - len) & ~7UL;
interp_params->map_addr = sp;
if (copy_to_user((void __user *) sp, interp_params->loadmap,
len) != 0)
return -EFAULT;
current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
}
/* force 16 byte _final_ alignment here for generality */
#define DLINFO_ITEMS 15
nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;
if (bprm->have_execfd)
nitems++;
csp = sp;
sp -= nitems * 2 * sizeof(unsigned long);
sp -= (bprm->envc + 1) * sizeof(char *); /* envv[] */
sp -= (bprm->argc + 1) * sizeof(char *); /* argv[] */
sp -= 1 * sizeof(unsigned long); /* argc */
csp -= sp & 15UL;
sp -= sp & 15UL;
/* put the ELF interpreter info on the stack */
#define NEW_AUX_ENT(id, val) \
do { \
struct { unsigned long _id, _val; } __user *ent, v; \
\
ent = (void __user *) csp; \
v._id = (id); \
v._val = (val); \
if (copy_to_user(ent + nr, &v, sizeof(v))) \
return -EFAULT; \
nr++; \
} while (0)
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_NULL, 0);
if (k_platform) {
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_PLATFORM,
(elf_addr_t) (unsigned long) u_platform);
}
if (k_base_platform) {
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_BASE_PLATFORM,
(elf_addr_t) (unsigned long) u_base_platform);
}
if (bprm->have_execfd) {
nr = 0;
csp -= 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
}
nr = 0;
csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
#ifdef ELF_HWCAP2
NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
#endif
NEW_AUX_ENT(AT_PAGESZ, PAGE_SIZE);
NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
NEW_AUX_ENT(AT_PHDR, exec_params->ph_addr);
NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
NEW_AUX_ENT(AT_PHNUM, exec_params->hdr.e_phnum);
NEW_AUX_ENT(AT_BASE, interp_params->elfhdr_addr);
if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0)
flags |= AT_FLAGS_PRESERVE_ARGV0;
NEW_AUX_ENT(AT_FLAGS, flags);
NEW_AUX_ENT(AT_ENTRY, exec_params->entry_addr);
NEW_AUX_ENT(AT_UID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
NEW_AUX_ENT(AT_EUID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
NEW_AUX_ENT(AT_GID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
NEW_AUX_ENT(AT_EGID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
NEW_AUX_ENT(AT_EXECFN, bprm->exec);
#ifdef ARCH_DLINFO
nr = 0;
csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);
/* ARCH_DLINFO must come last so platform specific code can enforce
* special alignment requirements on the AUXV if necessary (eg. PPC).
*/
ARCH_DLINFO;
#endif
#undef NEW_AUX_ENT
/* allocate room for argv[] and envv[] */
csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
envp = (elf_caddr_t __user *) csp;
csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
argv = (elf_caddr_t __user *) csp;
/* stack argc */
csp -= sizeof(unsigned long);
if (put_user(bprm->argc, (unsigned long __user *) csp))
return -EFAULT;
BUG_ON(csp != sp);
/* fill in the argv[] array */
#ifdef CONFIG_MMU
current->mm->arg_start = bprm->p;
#else
current->mm->arg_start = current->mm->start_stack -
(MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
#endif
p = (char __user *) current->mm->arg_start;
for (loop = bprm->argc; loop > 0; loop--) {
if (put_user((elf_caddr_t) p, argv++))
return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(NULL, argv))
return -EFAULT;
current->mm->arg_end = (unsigned long) p;
/* fill in the envv[] array */
current->mm->env_start = (unsigned long) p;
for (loop = bprm->envc; loop > 0; loop--) {
if (put_user((elf_caddr_t)(unsigned long) p, envp++))
return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(NULL, envp))
return -EFAULT;
current->mm->env_end = (unsigned long) p;
mm->start_stack = (unsigned long) sp;
return 0;
}
/*****************************************************************************/
/*
* load the appropriate binary image (executable or interpreter) into memory
* - we assume no MMU is available
* - if no other PIC bits are set in params->hdr->e_flags
* - we assume that the LOADable segments in the binary are independently relocatable
* - we assume R/O executable segments are shareable
* - else
* - we assume the loadable parts of the image to require fixed displacement
* - the image is not shareable
*/
static int elf_fdpic_map_file(struct elf_fdpic_params *params,
struct file *file,
struct mm_struct *mm,
const char *what)
{
struct elf_fdpic_loadmap *loadmap;
#ifdef CONFIG_MMU
struct elf_fdpic_loadseg *mseg;
unsigned long load_addr;
#endif
struct elf_fdpic_loadseg *seg;
struct elf_phdr *phdr;
unsigned nloads, tmp;
unsigned long stop;
int loop, ret;
/* allocate a load map table */
nloads = 0;
for (loop = 0; loop < params->hdr.e_phnum; loop++)
if (params->phdrs[loop].p_type == PT_LOAD)
nloads++;
if (nloads == 0)
return -ELIBBAD;
loadmap = kzalloc(struct_size(loadmap, segs, nloads), GFP_KERNEL);
if (!loadmap)
return -ENOMEM;
params->loadmap = loadmap;
loadmap->version = ELF_FDPIC_LOADMAP_VERSION;
loadmap->nsegs = nloads;
/* map the requested LOADs into the memory space */
switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
case ELF_FDPIC_FLAG_CONSTDISP:
case ELF_FDPIC_FLAG_CONTIGUOUS:
#ifndef CONFIG_MMU
ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
if (ret < 0)
return ret;
break;
#endif
default:
ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
if (ret < 0)
return ret;
break;
}
/* map the entry point */
if (params->hdr.e_entry) {
seg = loadmap->segs;
for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
if (params->hdr.e_entry >= seg->p_vaddr &&
params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
params->entry_addr =
(params->hdr.e_entry - seg->p_vaddr) +
seg->addr;
break;
}
}
}
/* determine where the program header table has wound up if mapped */
stop = params->hdr.e_phoff;
stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (phdr->p_type != PT_LOAD)
continue;
if (phdr->p_offset > params->hdr.e_phoff ||
phdr->p_offset + phdr->p_filesz < stop)
continue;
seg = loadmap->segs;
for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
if (phdr->p_vaddr >= seg->p_vaddr &&
phdr->p_vaddr + phdr->p_filesz <=
seg->p_vaddr + seg->p_memsz) {
params->ph_addr =
(phdr->p_vaddr - seg->p_vaddr) +
seg->addr +
params->hdr.e_phoff - phdr->p_offset;
break;
}
}
break;
}
/* determine where the dynamic section has wound up if there is one */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (phdr->p_type != PT_DYNAMIC)
continue;
seg = loadmap->segs;
for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
if (phdr->p_vaddr >= seg->p_vaddr &&
phdr->p_vaddr + phdr->p_memsz <=
seg->p_vaddr + seg->p_memsz) {
Elf_Dyn __user *dyn;
Elf_Sword d_tag;
params->dynamic_addr =
(phdr->p_vaddr - seg->p_vaddr) +
seg->addr;
/* check the dynamic section contains at least
* one item, and that the last item is a NULL
* entry */
if (phdr->p_memsz == 0 ||
phdr->p_memsz % sizeof(Elf_Dyn) != 0)
goto dynamic_error;
tmp = phdr->p_memsz / sizeof(Elf_Dyn);
dyn = (Elf_Dyn __user *)params->dynamic_addr;
if (get_user(d_tag, &dyn[tmp - 1].d_tag) ||
d_tag != 0)
goto dynamic_error;
break;
}
}
break;
}
/* now elide adjacent segments in the load map on MMU linux
* - on uClinux the holes between may actually be filled with system
* stuff or stuff from other processes
*/
#ifdef CONFIG_MMU
nloads = loadmap->nsegs;
mseg = loadmap->segs;
seg = mseg + 1;
for (loop = 1; loop < nloads; loop++) {
/* see if we have a candidate for merging */
if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
if (load_addr == (seg->addr & PAGE_MASK)) {
mseg->p_memsz +=
load_addr -
(mseg->addr + mseg->p_memsz);
mseg->p_memsz += seg->addr & ~PAGE_MASK;
mseg->p_memsz += seg->p_memsz;
loadmap->nsegs--;
continue;
}
}
mseg++;
if (mseg != seg)
*mseg = *seg;
}
#endif
kdebug("Mapped Object [%s]:", what);
kdebug("- elfhdr : %lx", params->elfhdr_addr);
kdebug("- entry : %lx", params->entry_addr);
kdebug("- PHDR[] : %lx", params->ph_addr);
kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
seg = loadmap->segs;
for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
loop,
seg->addr, seg->addr + seg->p_memsz - 1,
seg->p_vaddr, seg->p_memsz);
return 0;
dynamic_error:
printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
what, file_inode(file)->i_ino);
return -ELIBBAD;
}
/*****************************************************************************/
/*
* map a file with constant displacement under uClinux
*/
#ifndef CONFIG_MMU
static int elf_fdpic_map_file_constdisp_on_uclinux(
struct elf_fdpic_params *params,
struct file *file,
struct mm_struct *mm)
{
struct elf_fdpic_loadseg *seg;
struct elf_phdr *phdr;
unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0;
int loop, ret;
load_addr = params->load_addr;
seg = params->loadmap->segs;
/* determine the bounds of the contiguous overall allocation we must
* make */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (params->phdrs[loop].p_type != PT_LOAD)
continue;
if (base > phdr->p_vaddr)
base = phdr->p_vaddr;
if (top < phdr->p_vaddr + phdr->p_memsz)
top = phdr->p_vaddr + phdr->p_memsz;
}
/* allocate one big anon block for everything */
maddr = vm_mmap(NULL, load_addr, top - base,
PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, 0);
if (IS_ERR_VALUE(maddr))
return (int) maddr;
if (load_addr != 0)
load_addr += PAGE_ALIGN(top - base);
/* and then load the file segments into it */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
if (params->phdrs[loop].p_type != PT_LOAD)
continue;
seg->addr = maddr + (phdr->p_vaddr - base);
seg->p_vaddr = phdr->p_vaddr;
seg->p_memsz = phdr->p_memsz;
ret = read_code(file, seg->addr, phdr->p_offset,
phdr->p_filesz);
if (ret < 0)
return ret;
/* map the ELF header address if in this segment */
if (phdr->p_offset == 0)
params->elfhdr_addr = seg->addr;
/* clear any space allocated but not loaded */
if (phdr->p_filesz < phdr->p_memsz) {
if (clear_user((void *) (seg->addr + phdr->p_filesz),
phdr->p_memsz - phdr->p_filesz))
return -EFAULT;
}
if (mm) {
if (phdr->p_flags & PF_X) {
if (!mm->start_code) {
mm->start_code = seg->addr;
mm->end_code = seg->addr +
phdr->p_memsz;
}
} else if (!mm->start_data) {
mm->start_data = seg->addr;
mm->end_data = seg->addr + phdr->p_memsz;
}
}
seg++;
}
return 0;
}
#endif
/*****************************************************************************/
/*
* map a binary by direct mmap() of the individual PT_LOAD segments
*/
static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
struct file *file,
struct mm_struct *mm)
{
struct elf_fdpic_loadseg *seg;
struct elf_phdr *phdr;
unsigned long load_addr, delta_vaddr;
int loop, dvset;
load_addr = params->load_addr;
delta_vaddr = 0;
dvset = 0;
seg = params->loadmap->segs;
/* deal with each load segment separately */
phdr = params->phdrs;
for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
unsigned long maddr, disp, excess, excess1;
int prot = 0, flags;
if (phdr->p_type != PT_LOAD)
continue;
kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
(unsigned long) phdr->p_vaddr,
(unsigned long) phdr->p_offset,
(unsigned long) phdr->p_filesz,
(unsigned long) phdr->p_memsz);
/* determine the mapping parameters */
if (phdr->p_flags & PF_R) prot |= PROT_READ;
if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
flags = MAP_PRIVATE;
maddr = 0;
switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
case ELF_FDPIC_FLAG_INDEPENDENT:
/* PT_LOADs are independently locatable */
break;
case ELF_FDPIC_FLAG_HONOURVADDR:
/* the specified virtual address must be honoured */
maddr = phdr->p_vaddr;
flags |= MAP_FIXED;
break;
case ELF_FDPIC_FLAG_CONSTDISP:
/* constant displacement
* - can be mapped anywhere, but must be mapped as a
* unit
*/
if (!dvset) {
maddr = load_addr;
delta_vaddr = phdr->p_vaddr;
dvset = 1;
} else {
maddr = load_addr + phdr->p_vaddr - delta_vaddr;
flags |= MAP_FIXED;
}
break;
case ELF_FDPIC_FLAG_CONTIGUOUS:
/* contiguity handled later */
break;
default:
BUG();
}
maddr &= PAGE_MASK;
/* create the mapping */
disp = phdr->p_vaddr & ~PAGE_MASK;
maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
phdr->p_offset - disp);
kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
loop, phdr->p_memsz + disp, prot, flags,
phdr->p_offset - disp, maddr);
if (IS_ERR_VALUE(maddr))
return (int) maddr;
if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
ELF_FDPIC_FLAG_CONTIGUOUS)
load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
seg->addr = maddr + disp;
seg->p_vaddr = phdr->p_vaddr;
seg->p_memsz = phdr->p_memsz;
/* map the ELF header address if in this segment */
if (phdr->p_offset == 0)
params->elfhdr_addr = seg->addr;
/* clear the bit between beginning of mapping and beginning of
* PT_LOAD */
if (prot & PROT_WRITE && disp > 0) {
kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
if (clear_user((void __user *) maddr, disp))
return -EFAULT;
maddr += disp;
}
/* clear any space allocated but not loaded
* - on uClinux we can just clear the lot
* - on MMU linux we'll get a SIGBUS beyond the last page
* extant in the file
*/
excess = phdr->p_memsz - phdr->p_filesz;
excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
#ifdef CONFIG_MMU
if (excess > excess1) {
unsigned long xaddr = maddr + phdr->p_filesz + excess1;
unsigned long xmaddr;
flags |= MAP_FIXED | MAP_ANONYMOUS;
xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
prot, flags, 0);
kdebug("mmap[%d] <anon>"
" ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
loop, xaddr, excess - excess1, prot, flags,
xmaddr);
if (xmaddr != xaddr)
return -ENOMEM;
}
if (prot & PROT_WRITE && excess1 > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess1);
if (clear_user((void __user *) maddr + phdr->p_filesz,
excess1))
return -EFAULT;
}
#else
if (excess > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess);
if (clear_user((void *) maddr + phdr->p_filesz, excess))
return -EFAULT;
}
#endif
if (mm) {
if (phdr->p_flags & PF_X) {
if (!mm->start_code) {
mm->start_code = maddr;
mm->end_code = maddr + phdr->p_memsz;
}
} else if (!mm->start_data) {
mm->start_data = maddr;
mm->end_data = maddr + phdr->p_memsz;
}
}
seg++;
}
return 0;
}
/*****************************************************************************/
/*
* ELF-FDPIC core dumper
*
* Modelled on fs/exec.c:aout_core_dump()
* Jeremy Fitzhardinge <[email protected]>
*
* Modelled on fs/binfmt_elf.c core dumper
*/
#ifdef CONFIG_ELF_CORE
struct elf_prstatus_fdpic
{
struct elf_prstatus_common common;
elf_gregset_t pr_reg; /* GP registers */
/* When using FDPIC, the loadmap addresses need to be communicated
* to GDB in order for GDB to do the necessary relocations. The
* fields (below) used to communicate this information are placed
* immediately after ``pr_reg'', so that the loadmap addresses may
* be viewed as part of the register set if so desired.
*/
unsigned long pr_exec_fdpic_loadmap;
unsigned long pr_interp_fdpic_loadmap;
int pr_fpvalid; /* True if math co-processor being used. */
};
/* An ELF note in memory */
struct memelfnote
{
const char *name;
int type;
unsigned int datasz;
void *data;
};
static int notesize(struct memelfnote *en)
{
int sz;
sz = sizeof(struct elf_note);
sz += roundup(strlen(en->name) + 1, 4);
sz += roundup(en->datasz, 4);
return sz;
}
/* #define DEBUG */
static int writenote(struct memelfnote *men, struct coredump_params *cprm)
{
struct elf_note en;
en.n_namesz = strlen(men->name) + 1;
en.n_descsz = men->datasz;
en.n_type = men->type;
return dump_emit(cprm, &en, sizeof(en)) &&
dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
}
static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
{
memcpy(elf->e_ident, ELFMAG, SELFMAG);
elf->e_ident[EI_CLASS] = ELF_CLASS;
elf->e_ident[EI_DATA] = ELF_DATA;
elf->e_ident[EI_VERSION] = EV_CURRENT;
elf->e_ident[EI_OSABI] = ELF_OSABI;
memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
elf->e_type = ET_CORE;
elf->e_machine = ELF_ARCH;
elf->e_version = EV_CURRENT;
elf->e_entry = 0;
elf->e_phoff = sizeof(struct elfhdr);
elf->e_shoff = 0;
elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
elf->e_phnum = segs;
elf->e_shentsize = 0;
elf->e_shnum = 0;
elf->e_shstrndx = 0;
return;
}
static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
{
phdr->p_type = PT_NOTE;
phdr->p_offset = offset;
phdr->p_vaddr = 0;
phdr->p_paddr = 0;
phdr->p_filesz = sz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
phdr->p_align = 4;
return;
}
static inline void fill_note(struct memelfnote *note, const char *name, int type,
unsigned int sz, void *data)
{
note->name = name;
note->type = type;
note->datasz = sz;
note->data = data;
return;
}
/*
* fill up all the fields in prstatus from the given task struct, except
* registers which need to be filled up separately.
*/
static void fill_prstatus(struct elf_prstatus_common *prstatus,
struct task_struct *p, long signr)
{
prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
prstatus->pr_sigpend = p->pending.signal.sig[0];
prstatus->pr_sighold = p->blocked.sig[0];
rcu_read_lock();
prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
rcu_read_unlock();
prstatus->pr_pid = task_pid_vnr(p);
prstatus->pr_pgrp = task_pgrp_vnr(p);
prstatus->pr_sid = task_session_vnr(p);
if (thread_group_leader(p)) {
struct task_cputime cputime;
/*
* This is the record for the group leader. It shows the
* group-wide total, not its individual thread total.
*/
thread_group_cputime(p, &cputime);
prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
} else {
u64 utime, stime;
task_cputime(p, &utime, &stime);
prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
}
prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
}
static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
struct mm_struct *mm)
{
const struct cred *cred;
unsigned int i, len;
unsigned int state;
/* first copy the parameters from user space */
memset(psinfo, 0, sizeof(struct elf_prpsinfo));
len = mm->arg_end - mm->arg_start;
if (len >= ELF_PRARGSZ)
len = ELF_PRARGSZ - 1;
if (copy_from_user(&psinfo->pr_psargs,
(const char __user *) mm->arg_start, len))
return -EFAULT;
for (i = 0; i < len; i++)
if (psinfo->pr_psargs[i] == 0)
psinfo->pr_psargs[i] = ' ';
psinfo->pr_psargs[len] = 0;
rcu_read_lock();
psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
rcu_read_unlock();
psinfo->pr_pid = task_pid_vnr(p);
psinfo->pr_pgrp = task_pgrp_vnr(p);
psinfo->pr_sid = task_session_vnr(p);
state = READ_ONCE(p->__state);
i = state ? ffz(~state) + 1 : 0;
psinfo->pr_state = i;
psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
psinfo->pr_zomb = psinfo->pr_sname == 'Z';
psinfo->pr_nice = task_nice(p);
psinfo->pr_flag = p->flags;
rcu_read_lock();
cred = __task_cred(p);
SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
rcu_read_unlock();
strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
return 0;
}
/* Here is the structure in which status of each thread is captured. */
struct elf_thread_status
{
struct elf_thread_status *next;
struct elf_prstatus_fdpic prstatus; /* NT_PRSTATUS */
elf_fpregset_t fpu; /* NT_PRFPREG */
struct memelfnote notes[2];
int num_notes;
};
/*
* In order to add the specific thread information for the elf file format,
* we need to keep a linked list of every thread's pr_status and then create
* a single section for them in the final core file.
*/
static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_struct *p, int *sz)
{
const struct user_regset_view *view = task_user_regset_view(p);
struct elf_thread_status *t;
int i, ret;
t = kzalloc(sizeof(struct elf_thread_status), GFP_KERNEL);
if (!t)
return t;
fill_prstatus(&t->prstatus.common, p, signr);
t->prstatus.pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
t->prstatus.pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
regset_get(p, &view->regsets[0],
sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
&t->prstatus);
t->num_notes++;
*sz += notesize(&t->notes[0]);
for (i = 1; i < view->n; ++i) {
const struct user_regset *regset = &view->regsets[i];
if (regset->core_note_type != NT_PRFPREG)
continue;
if (regset->active && regset->active(p, regset) <= 0)
continue;
ret = regset_get(p, regset, sizeof(t->fpu), &t->fpu);
if (ret >= 0)
t->prstatus.pr_fpvalid = 1;
break;
}
if (t->prstatus.pr_fpvalid) {
fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
&t->fpu);
t->num_notes++;
*sz += notesize(&t->notes[1]);
}
return t;
}
static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
elf_addr_t e_shoff, int segs)
{
elf->e_shoff = e_shoff;
elf->e_shentsize = sizeof(*shdr4extnum);
elf->e_shnum = 1;
elf->e_shstrndx = SHN_UNDEF;
memset(shdr4extnum, 0, sizeof(*shdr4extnum));
shdr4extnum->sh_type = SHT_NULL;
shdr4extnum->sh_size = elf->e_shnum;
shdr4extnum->sh_link = elf->e_shstrndx;
shdr4extnum->sh_info = segs;
}
/*
* dump the segments for an MMU process
*/
static bool elf_fdpic_dump_segments(struct coredump_params *cprm,
struct core_vma_metadata *vma_meta,
int vma_count)
{
int i;
for (i = 0; i < vma_count; i++) {
struct core_vma_metadata *meta = vma_meta + i;
if (!dump_user_range(cprm, meta->start, meta->dump_size))
return false;
}
return true;
}
/*
* Actual dumper
*
* This is a two-pass process; first we find the offsets of the bits,
* and then they are actually written out. If we run out of core limit
* we just truncate.
*/
static int elf_fdpic_core_dump(struct coredump_params *cprm)
{
int has_dumped = 0;
int segs;
int i;
struct elfhdr *elf = NULL;
loff_t offset = 0, dataoff;
struct memelfnote psinfo_note, auxv_note;
struct elf_prpsinfo *psinfo = NULL; /* NT_PRPSINFO */
struct elf_thread_status *thread_list = NULL;
int thread_status_size = 0;
elf_addr_t *auxv;
struct elf_phdr *phdr4note = NULL;
struct elf_shdr *shdr4extnum = NULL;
Elf_Half e_phnum;
elf_addr_t e_shoff;
struct core_thread *ct;
struct elf_thread_status *tmp;
/* alloc memory for large data structures: too large to be on stack */
elf = kmalloc(sizeof(*elf), GFP_KERNEL);
if (!elf)
goto end_coredump;
psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
if (!psinfo)
goto end_coredump;
for (ct = current->signal->core_state->dumper.next;
ct; ct = ct->next) {
tmp = elf_dump_thread_status(cprm->siginfo->si_signo,
ct->task, &thread_status_size);
if (!tmp)
goto end_coredump;
tmp->next = thread_list;
thread_list = tmp;
}
/* now collect the dump for the current */
tmp = elf_dump_thread_status(cprm->siginfo->si_signo,
current, &thread_status_size);
if (!tmp)
goto end_coredump;
tmp->next = thread_list;
thread_list = tmp;
segs = cprm->vma_count + elf_core_extra_phdrs(cprm);
/* for notes section */
segs++;
/* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
* this, kernel supports extended numbering. Have a look at
* include/linux/elf.h for further information. */
e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
/* Set up header */
fill_elf_fdpic_header(elf, e_phnum);
has_dumped = 1;
/*
* Set up the notes in similar form to SVR4 core dumps made
* with info from their /proc.
*/
fill_psinfo(psinfo, current->group_leader, current->mm);
fill_note(&psinfo_note, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
thread_status_size += notesize(&psinfo_note);
auxv = (elf_addr_t *) current->mm->saved_auxv;
i = 0;
do
i += 2;
while (auxv[i - 2] != AT_NULL);
fill_note(&auxv_note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
thread_status_size += notesize(&auxv_note);
offset = sizeof(*elf); /* ELF header */
offset += segs * sizeof(struct elf_phdr); /* Program headers */
/* Write notes phdr entry */
phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
if (!phdr4note)
goto end_coredump;
fill_elf_note_phdr(phdr4note, thread_status_size, offset);
offset += thread_status_size;
/* Page-align dumped data */
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
offset += cprm->vma_data_size;
offset += elf_core_extra_data_size(cprm);
e_shoff = offset;
if (e_phnum == PN_XNUM) {
shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
if (!shdr4extnum)
goto end_coredump;
fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
}
offset = dataoff;
if (!dump_emit(cprm, elf, sizeof(*elf)))
goto end_coredump;
if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
goto end_coredump;
/* write program headers for segments dump */
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *meta = cprm->vma_meta + i;
struct elf_phdr phdr;
size_t sz;
sz = meta->end - meta->start;
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
phdr.p_vaddr = meta->start;
phdr.p_paddr = 0;
phdr.p_filesz = meta->dump_size;
phdr.p_memsz = sz;
offset += phdr.p_filesz;
phdr.p_flags = 0;
if (meta->flags & VM_READ)
phdr.p_flags |= PF_R;
if (meta->flags & VM_WRITE)
phdr.p_flags |= PF_W;
if (meta->flags & VM_EXEC)
phdr.p_flags |= PF_X;
phdr.p_align = ELF_EXEC_PAGESIZE;
if (!dump_emit(cprm, &phdr, sizeof(phdr)))
goto end_coredump;
}
if (!elf_core_write_extra_phdrs(cprm, offset))
goto end_coredump;
/* write out the notes section */
if (!writenote(thread_list->notes, cprm))
goto end_coredump;
if (!writenote(&psinfo_note, cprm))
goto end_coredump;
if (!writenote(&auxv_note, cprm))
goto end_coredump;
for (i = 1; i < thread_list->num_notes; i++)
if (!writenote(thread_list->notes + i, cprm))
goto end_coredump;
/* write out the thread status notes section */
for (tmp = thread_list->next; tmp; tmp = tmp->next) {
for (i = 0; i < tmp->num_notes; i++)
if (!writenote(&tmp->notes[i], cprm))
goto end_coredump;
}
dump_skip_to(cprm, dataoff);
if (!elf_fdpic_dump_segments(cprm, cprm->vma_meta, cprm->vma_count))
goto end_coredump;
if (!elf_core_write_extra_data(cprm))
goto end_coredump;
if (e_phnum == PN_XNUM) {
if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
goto end_coredump;
}
if (cprm->file->f_pos != offset) {
/* Sanity check */
printk(KERN_WARNING
"elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
cprm->file->f_pos, offset);
}
end_coredump:
while (thread_list) {
tmp = thread_list;
thread_list = thread_list->next;
kfree(tmp);
}
kfree(phdr4note);
kfree(elf);
kfree(psinfo);
kfree(shdr4extnum);
return has_dumped;
}
#endif /* CONFIG_ELF_CORE */
| linux-master | fs/binfmt_elf_fdpic.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/readdir.c
*
* Copyright (C) 1995 Linus Torvalds
*/
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/dirent.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/compat.h>
#include <linux/uaccess.h>
#include <asm/unaligned.h>
/*
* Some filesystems were never converted to '->iterate_shared()'
* and their directory iterators want the inode lock held for
* writing. This wrapper allows for converting from the shared
* semantics to the exclusive inode use.
*/
int wrap_directory_iterator(struct file *file,
struct dir_context *ctx,
int (*iter)(struct file *, struct dir_context *))
{
struct inode *inode = file_inode(file);
int ret;
/*
* We'd love to have an 'inode_upgrade_trylock()' operation,
* see the comment in mmap_upgrade_trylock() in mm/memory.c.
*
* But considering this is for "filesystems that never got
* converted", it really doesn't matter.
*
* Also note that since we have to return with the lock held
* for reading, we can't use the "killable()" locking here,
* since we do need to get the lock even if we're dying.
*
* We could do the write part killably and then get the read
* lock unconditionally if it mattered, but see above on why
* this does the very simplistic conversion.
*/
up_read(&inode->i_rwsem);
down_write(&inode->i_rwsem);
/*
* Since we dropped the inode lock, we should do the
* DEADDIR test again. See 'iterate_dir()' below.
*
* Note that we don't need to re-do the f_pos games,
* since the file must be locked wrt f_pos anyway.
*/
ret = -ENOENT;
if (!IS_DEADDIR(inode))
ret = iter(file, ctx);
downgrade_write(&inode->i_rwsem);
return ret;
}
EXPORT_SYMBOL(wrap_directory_iterator);
/*
* Note the "unsafe_put_user() semantics: we goto a
* label for errors.
*/
#define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \
char __user *dst = (_dst); \
const char *src = (_src); \
size_t len = (_len); \
unsafe_put_user(0, dst+len, label); \
unsafe_copy_to_user(dst, src, len, label); \
} while (0)
int iterate_dir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
int res = -ENOTDIR;
if (!file->f_op->iterate_shared)
goto out;
res = security_file_permission(file, MAY_READ);
if (res)
goto out;
res = down_read_killable(&inode->i_rwsem);
if (res)
goto out;
res = -ENOENT;
if (!IS_DEADDIR(inode)) {
ctx->pos = file->f_pos;
res = file->f_op->iterate_shared(file, ctx);
file->f_pos = ctx->pos;
fsnotify_access(file);
file_accessed(file);
}
inode_unlock_shared(inode);
out:
return res;
}
EXPORT_SYMBOL(iterate_dir);
/*
* POSIX says that a dirent name cannot contain NULL or a '/'.
*
* It's not 100% clear what we should really do in this case.
* The filesystem is clearly corrupted, but returning a hard
* error means that you now don't see any of the other names
* either, so that isn't a perfect alternative.
*
* And if you return an error, what error do you use? Several
* filesystems seem to have decided on EUCLEAN being the error
* code for EFSCORRUPTED, and that may be the error to use. Or
* just EIO, which is perhaps more obvious to users.
*
* In order to see the other file names in the directory, the
* caller might want to make this a "soft" error: skip the
* entry, and return the error at the end instead.
*
* Note that this should likely do a "memchr(name, 0, len)"
* check too, since that would be filesystem corruption as
* well. However, that case can't actually confuse user space,
* which has to do a strlen() on the name anyway to find the
* filename length, and the above "soft error" worry means
* that it's probably better left alone until we have that
* issue clarified.
*
* Note the PATH_MAX check - it's arbitrary but the real
* kernel limit on a possible path component, not NAME_MAX,
* which is the technical standard limit.
*/
static int verify_dirent_name(const char *name, int len)
{
if (len <= 0 || len >= PATH_MAX)
return -EIO;
if (memchr(name, '/', len))
return -EIO;
return 0;
}
/*
* Traditional linux readdir() handling..
*
* "count=1" is a special case, meaning that the buffer is one
* dirent-structure in size and that the code can't handle more
* anyway. Thus the special "fillonedir()" function for that
* case (the low-level handlers don't need to care about this).
*/
#ifdef __ARCH_WANT_OLD_READDIR
struct old_linux_dirent {
unsigned long d_ino;
unsigned long d_offset;
unsigned short d_namlen;
char d_name[];
};
struct readdir_callback {
struct dir_context ctx;
struct old_linux_dirent __user * dirent;
int result;
};
static bool fillonedir(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct readdir_callback *buf =
container_of(ctx, struct readdir_callback, ctx);
struct old_linux_dirent __user * dirent;
unsigned long d_ino;
if (buf->result)
return false;
buf->result = verify_dirent_name(name, namlen);
if (buf->result)
return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->result = -EOVERFLOW;
return false;
}
buf->result++;
dirent = buf->dirent;
if (!user_write_access_begin(dirent,
(unsigned long)(dirent->d_name + namlen + 1) -
(unsigned long)dirent))
goto efault;
unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
unsafe_put_user(offset, &dirent->d_offset, efault_end);
unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
user_write_access_end();
return true;
efault_end:
user_write_access_end();
efault:
buf->result = -EFAULT;
return false;
}
SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
struct old_linux_dirent __user *, dirent, unsigned int, count)
{
int error;
struct fd f = fdget_pos(fd);
struct readdir_callback buf = {
.ctx.actor = fillonedir,
.dirent = dirent
};
if (!f.file)
return -EBADF;
error = iterate_dir(f.file, &buf.ctx);
if (buf.result)
error = buf.result;
fdput_pos(f);
return error;
}
#endif /* __ARCH_WANT_OLD_READDIR */
/*
* New, all-improved, singing, dancing, iBCS2-compliant getdents()
* interface.
*/
struct linux_dirent {
unsigned long d_ino;
unsigned long d_off;
unsigned short d_reclen;
char d_name[];
};
struct getdents_callback {
struct dir_context ctx;
struct linux_dirent __user * current_dir;
int prev_reclen;
int count;
int error;
};
static bool filldir(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct linux_dirent __user *dirent, *prev;
struct getdents_callback *buf =
container_of(ctx, struct getdents_callback, ctx);
unsigned long d_ino;
int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
sizeof(long));
int prev_reclen;
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
return false;
buf->error = -EINVAL; /* only used if we fail.. */
if (reclen > buf->count)
return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->error = -EOVERFLOW;
return false;
}
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
return false;
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
goto efault;
/* This might be 'dirent->d_off', but if so it will get overwritten */
unsafe_put_user(offset, &prev->d_off, efault_end);
unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
user_write_access_end();
buf->current_dir = (void __user *)dirent + reclen;
buf->prev_reclen = reclen;
buf->count -= reclen;
return true;
efault_end:
user_write_access_end();
efault:
buf->error = -EFAULT;
return false;
}
SYSCALL_DEFINE3(getdents, unsigned int, fd,
struct linux_dirent __user *, dirent, unsigned int, count)
{
struct fd f;
struct getdents_callback buf = {
.ctx.actor = filldir,
.count = count,
.current_dir = dirent
};
int error;
f = fdget_pos(fd);
if (!f.file)
return -EBADF;
error = iterate_dir(f.file, &buf.ctx);
if (error >= 0)
error = buf.error;
if (buf.prev_reclen) {
struct linux_dirent __user * lastdirent;
lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
if (put_user(buf.ctx.pos, &lastdirent->d_off))
error = -EFAULT;
else
error = count - buf.count;
}
fdput_pos(f);
return error;
}
struct getdents_callback64 {
struct dir_context ctx;
struct linux_dirent64 __user * current_dir;
int prev_reclen;
int count;
int error;
};
static bool filldir64(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct linux_dirent64 __user *dirent, *prev;
struct getdents_callback64 *buf =
container_of(ctx, struct getdents_callback64, ctx);
int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
sizeof(u64));
int prev_reclen;
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
return false;
buf->error = -EINVAL; /* only used if we fail.. */
if (reclen > buf->count)
return false;
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
return false;
dirent = buf->current_dir;
prev = (void __user *)dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
goto efault;
/* This might be 'dirent->d_off', but if so it will get overwritten */
unsafe_put_user(offset, &prev->d_off, efault_end);
unsafe_put_user(ino, &dirent->d_ino, efault_end);
unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
unsafe_put_user(d_type, &dirent->d_type, efault_end);
unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
user_write_access_end();
buf->prev_reclen = reclen;
buf->current_dir = (void __user *)dirent + reclen;
buf->count -= reclen;
return true;
efault_end:
user_write_access_end();
efault:
buf->error = -EFAULT;
return false;
}
SYSCALL_DEFINE3(getdents64, unsigned int, fd,
struct linux_dirent64 __user *, dirent, unsigned int, count)
{
struct fd f;
struct getdents_callback64 buf = {
.ctx.actor = filldir64,
.count = count,
.current_dir = dirent
};
int error;
f = fdget_pos(fd);
if (!f.file)
return -EBADF;
error = iterate_dir(f.file, &buf.ctx);
if (error >= 0)
error = buf.error;
if (buf.prev_reclen) {
struct linux_dirent64 __user * lastdirent;
typeof(lastdirent->d_off) d_off = buf.ctx.pos;
lastdirent = (void __user *) buf.current_dir - buf.prev_reclen;
if (put_user(d_off, &lastdirent->d_off))
error = -EFAULT;
else
error = count - buf.count;
}
fdput_pos(f);
return error;
}
#ifdef CONFIG_COMPAT
struct compat_old_linux_dirent {
compat_ulong_t d_ino;
compat_ulong_t d_offset;
unsigned short d_namlen;
char d_name[];
};
struct compat_readdir_callback {
struct dir_context ctx;
struct compat_old_linux_dirent __user *dirent;
int result;
};
static bool compat_fillonedir(struct dir_context *ctx, const char *name,
int namlen, loff_t offset, u64 ino,
unsigned int d_type)
{
struct compat_readdir_callback *buf =
container_of(ctx, struct compat_readdir_callback, ctx);
struct compat_old_linux_dirent __user *dirent;
compat_ulong_t d_ino;
if (buf->result)
return false;
buf->result = verify_dirent_name(name, namlen);
if (buf->result)
return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->result = -EOVERFLOW;
return false;
}
buf->result++;
dirent = buf->dirent;
if (!user_write_access_begin(dirent,
(unsigned long)(dirent->d_name + namlen + 1) -
(unsigned long)dirent))
goto efault;
unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
unsafe_put_user(offset, &dirent->d_offset, efault_end);
unsafe_put_user(namlen, &dirent->d_namlen, efault_end);
unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
user_write_access_end();
return true;
efault_end:
user_write_access_end();
efault:
buf->result = -EFAULT;
return false;
}
COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
{
int error;
struct fd f = fdget_pos(fd);
struct compat_readdir_callback buf = {
.ctx.actor = compat_fillonedir,
.dirent = dirent
};
if (!f.file)
return -EBADF;
error = iterate_dir(f.file, &buf.ctx);
if (buf.result)
error = buf.result;
fdput_pos(f);
return error;
}
struct compat_linux_dirent {
compat_ulong_t d_ino;
compat_ulong_t d_off;
unsigned short d_reclen;
char d_name[];
};
struct compat_getdents_callback {
struct dir_context ctx;
struct compat_linux_dirent __user *current_dir;
int prev_reclen;
int count;
int error;
};
static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct compat_linux_dirent __user *dirent, *prev;
struct compat_getdents_callback *buf =
container_of(ctx, struct compat_getdents_callback, ctx);
compat_ulong_t d_ino;
int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
namlen + 2, sizeof(compat_long_t));
int prev_reclen;
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
return false;
buf->error = -EINVAL; /* only used if we fail.. */
if (reclen > buf->count)
return false;
d_ino = ino;
if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
buf->error = -EOVERFLOW;
return false;
}
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
return false;
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;
if (!user_write_access_begin(prev, reclen + prev_reclen))
goto efault;
unsafe_put_user(offset, &prev->d_off, efault_end);
unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
user_write_access_end();
buf->prev_reclen = reclen;
buf->current_dir = (void __user *)dirent + reclen;
buf->count -= reclen;
return true;
efault_end:
user_write_access_end();
efault:
buf->error = -EFAULT;
return false;
}
COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
struct compat_linux_dirent __user *, dirent, unsigned int, count)
{
struct fd f;
struct compat_getdents_callback buf = {
.ctx.actor = compat_filldir,
.current_dir = dirent,
.count = count
};
int error;
f = fdget_pos(fd);
if (!f.file)
return -EBADF;
error = iterate_dir(f.file, &buf.ctx);
if (error >= 0)
error = buf.error;
if (buf.prev_reclen) {
struct compat_linux_dirent __user * lastdirent;
lastdirent = (void __user *)buf.current_dir - buf.prev_reclen;
if (put_user(buf.ctx.pos, &lastdirent->d_off))
error = -EFAULT;
else
error = count - buf.count;
}
fdput_pos(f);
return error;
}
#endif
| linux-master | fs/readdir.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/locks.c
*
* We implement four types of file locks: BSD locks, posix locks, open
* file description locks, and leases. For details about BSD locks,
* see the flock(2) man page; for details about the other three, see
* fcntl(2).
*
*
* Locking conflicts and dependencies:
* If multiple threads attempt to lock the same byte (or flock the same file)
* only one can be granted the lock, and other must wait their turn.
* The first lock has been "applied" or "granted", the others are "waiting"
* and are "blocked" by the "applied" lock..
*
* Waiting and applied locks are all kept in trees whose properties are:
*
* - the root of a tree may be an applied or waiting lock.
* - every other node in the tree is a waiting lock that
* conflicts with every ancestor of that node.
*
* Every such tree begins life as a waiting singleton which obviously
* satisfies the above properties.
*
* The only ways we modify trees preserve these properties:
*
* 1. We may add a new leaf node, but only after first verifying that it
* conflicts with all of its ancestors.
* 2. We may remove the root of a tree, creating a new singleton
* tree from the root and N new trees rooted in the immediate
* children.
* 3. If the root of a tree is not currently an applied lock, we may
* apply it (if possible).
* 4. We may upgrade the root of the tree (either extend its range,
* or upgrade its entire range from read to write).
*
* When an applied lock is modified in a way that reduces or downgrades any
* part of its range, we remove all its children (2 above). This particularly
* happens when a lock is unlocked.
*
* For each of those child trees we "wake up" the thread which is
* waiting for the lock so it can continue handling as follows: if the
* root of the tree applies, we do so (3). If it doesn't, it must
* conflict with some applied lock. We remove (wake up) all of its children
* (2), and add it is a new leaf to the tree rooted in the applied
* lock (1). We then repeat the process recursively with those
* children.
*
*/
#include <linux/capability.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/filelock.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/security.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/time.h>
#include <linux/rcupdate.h>
#include <linux/pid_namespace.h>
#include <linux/hashtable.h>
#include <linux/percpu.h>
#include <linux/sysctl.h>
#define CREATE_TRACE_POINTS
#include <trace/events/filelock.h>
#include <linux/uaccess.h>
#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
#define IS_REMOTELCK(fl) (fl->fl_pid <= 0)
static bool lease_breaking(struct file_lock *fl)
{
return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
}
static int target_leasetype(struct file_lock *fl)
{
if (fl->fl_flags & FL_UNLOCK_PENDING)
return F_UNLCK;
if (fl->fl_flags & FL_DOWNGRADE_PENDING)
return F_RDLCK;
return fl->fl_type;
}
static int leases_enable = 1;
static int lease_break_time = 45;
#ifdef CONFIG_SYSCTL
static struct ctl_table locks_sysctls[] = {
{
.procname = "leases-enable",
.data = &leases_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#ifdef CONFIG_MMU
{
.procname = "lease-break-time",
.data = &lease_break_time,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif /* CONFIG_MMU */
{}
};
static int __init init_fs_locks_sysctls(void)
{
register_sysctl_init("fs", locks_sysctls);
return 0;
}
early_initcall(init_fs_locks_sysctls);
#endif /* CONFIG_SYSCTL */
/*
* The global file_lock_list is only used for displaying /proc/locks, so we
* keep a list on each CPU, with each list protected by its own spinlock.
* Global serialization is done using file_rwsem.
*
* Note that alterations to the list also require that the relevant flc_lock is
* held.
*/
struct file_lock_list_struct {
spinlock_t lock;
struct hlist_head hlist;
};
static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
/*
* The blocked_hash is used to find POSIX lock loops for deadlock detection.
* It is protected by blocked_lock_lock.
*
* We hash locks by lockowner in order to optimize searching for the lock a
* particular lockowner is waiting on.
*
* FIXME: make this value scale via some heuristic? We generally will want more
* buckets when we have more lockowners holding locks, but that's a little
* difficult to determine without knowing what the workload will look like.
*/
#define BLOCKED_HASH_BITS 7
static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
/*
* This lock protects the blocked_hash. Generally, if you're accessing it, you
* want to be holding this lock.
*
* In addition, it also protects the fl->fl_blocked_requests list, and the
* fl->fl_blocker pointer for file_lock structures that are acting as lock
* requests (in contrast to those that are acting as records of acquired locks).
*
* Note that when we acquire this lock in order to change the above fields,
* we often hold the flc_lock as well. In certain cases, when reading the fields
* protected by this lock, we can skip acquiring it iff we already hold the
* flc_lock.
*/
static DEFINE_SPINLOCK(blocked_lock_lock);
static struct kmem_cache *flctx_cache __read_mostly;
static struct kmem_cache *filelock_cache __read_mostly;
static struct file_lock_context *
locks_get_lock_context(struct inode *inode, int type)
{
struct file_lock_context *ctx;
/* paired with cmpxchg() below */
ctx = locks_inode_context(inode);
if (likely(ctx) || type == F_UNLCK)
goto out;
ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
if (!ctx)
goto out;
spin_lock_init(&ctx->flc_lock);
INIT_LIST_HEAD(&ctx->flc_flock);
INIT_LIST_HEAD(&ctx->flc_posix);
INIT_LIST_HEAD(&ctx->flc_lease);
/*
* Assign the pointer if it's not already assigned. If it is, then
* free the context we just allocated.
*/
if (cmpxchg(&inode->i_flctx, NULL, ctx)) {
kmem_cache_free(flctx_cache, ctx);
ctx = locks_inode_context(inode);
}
out:
trace_locks_get_lock_context(inode, type, ctx);
return ctx;
}
static void
locks_dump_ctx_list(struct list_head *list, char *list_type)
{
struct file_lock *fl;
list_for_each_entry(fl, list, fl_list) {
pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
}
}
static void
locks_check_ctx_lists(struct inode *inode)
{
struct file_lock_context *ctx = inode->i_flctx;
if (unlikely(!list_empty(&ctx->flc_flock) ||
!list_empty(&ctx->flc_posix) ||
!list_empty(&ctx->flc_lease))) {
pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
inode->i_ino);
locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
}
}
static void
locks_check_ctx_file_list(struct file *filp, struct list_head *list,
char *list_type)
{
struct file_lock *fl;
struct inode *inode = file_inode(filp);
list_for_each_entry(fl, list, fl_list)
if (fl->fl_file == filp)
pr_warn("Leaked %s lock on dev=0x%x:0x%x ino=0x%lx "
" fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n",
list_type, MAJOR(inode->i_sb->s_dev),
MINOR(inode->i_sb->s_dev), inode->i_ino,
fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
}
void
locks_free_lock_context(struct inode *inode)
{
struct file_lock_context *ctx = locks_inode_context(inode);
if (unlikely(ctx)) {
locks_check_ctx_lists(inode);
kmem_cache_free(flctx_cache, ctx);
}
}
static void locks_init_lock_heads(struct file_lock *fl)
{
INIT_HLIST_NODE(&fl->fl_link);
INIT_LIST_HEAD(&fl->fl_list);
INIT_LIST_HEAD(&fl->fl_blocked_requests);
INIT_LIST_HEAD(&fl->fl_blocked_member);
init_waitqueue_head(&fl->fl_wait);
}
/* Allocate an empty lock structure. */
struct file_lock *locks_alloc_lock(void)
{
struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
if (fl)
locks_init_lock_heads(fl);
return fl;
}
EXPORT_SYMBOL_GPL(locks_alloc_lock);
void locks_release_private(struct file_lock *fl)
{
BUG_ON(waitqueue_active(&fl->fl_wait));
BUG_ON(!list_empty(&fl->fl_list));
BUG_ON(!list_empty(&fl->fl_blocked_requests));
BUG_ON(!list_empty(&fl->fl_blocked_member));
BUG_ON(!hlist_unhashed(&fl->fl_link));
if (fl->fl_ops) {
if (fl->fl_ops->fl_release_private)
fl->fl_ops->fl_release_private(fl);
fl->fl_ops = NULL;
}
if (fl->fl_lmops) {
if (fl->fl_lmops->lm_put_owner) {
fl->fl_lmops->lm_put_owner(fl->fl_owner);
fl->fl_owner = NULL;
}
fl->fl_lmops = NULL;
}
}
EXPORT_SYMBOL_GPL(locks_release_private);
/**
* locks_owner_has_blockers - Check for blocking lock requests
* @flctx: file lock context
* @owner: lock owner
*
* Return values:
* %true: @owner has at least one blocker
* %false: @owner has no blockers
*/
bool locks_owner_has_blockers(struct file_lock_context *flctx,
fl_owner_t owner)
{
struct file_lock *fl;
spin_lock(&flctx->flc_lock);
list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
if (fl->fl_owner != owner)
continue;
if (!list_empty(&fl->fl_blocked_requests)) {
spin_unlock(&flctx->flc_lock);
return true;
}
}
spin_unlock(&flctx->flc_lock);
return false;
}
EXPORT_SYMBOL_GPL(locks_owner_has_blockers);
/* Free a lock which is not in use. */
void locks_free_lock(struct file_lock *fl)
{
locks_release_private(fl);
kmem_cache_free(filelock_cache, fl);
}
EXPORT_SYMBOL(locks_free_lock);
static void
locks_dispose_list(struct list_head *dispose)
{
struct file_lock *fl;
while (!list_empty(dispose)) {
fl = list_first_entry(dispose, struct file_lock, fl_list);
list_del_init(&fl->fl_list);
locks_free_lock(fl);
}
}
void locks_init_lock(struct file_lock *fl)
{
memset(fl, 0, sizeof(struct file_lock));
locks_init_lock_heads(fl);
}
EXPORT_SYMBOL(locks_init_lock);
/*
* Initialize a new lock from an existing file_lock structure.
*/
void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
{
new->fl_owner = fl->fl_owner;
new->fl_pid = fl->fl_pid;
new->fl_file = NULL;
new->fl_flags = fl->fl_flags;
new->fl_type = fl->fl_type;
new->fl_start = fl->fl_start;
new->fl_end = fl->fl_end;
new->fl_lmops = fl->fl_lmops;
new->fl_ops = NULL;
if (fl->fl_lmops) {
if (fl->fl_lmops->lm_get_owner)
fl->fl_lmops->lm_get_owner(fl->fl_owner);
}
}
EXPORT_SYMBOL(locks_copy_conflock);
void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
{
/* "new" must be a freshly-initialized lock */
WARN_ON_ONCE(new->fl_ops);
locks_copy_conflock(new, fl);
new->fl_file = fl->fl_file;
new->fl_ops = fl->fl_ops;
if (fl->fl_ops) {
if (fl->fl_ops->fl_copy_lock)
fl->fl_ops->fl_copy_lock(new, fl);
}
}
EXPORT_SYMBOL(locks_copy_lock);
static void locks_move_blocks(struct file_lock *new, struct file_lock *fl)
{
struct file_lock *f;
/*
* As ctx->flc_lock is held, new requests cannot be added to
* ->fl_blocked_requests, so we don't need a lock to check if it
* is empty.
*/
if (list_empty(&fl->fl_blocked_requests))
return;
spin_lock(&blocked_lock_lock);
list_splice_init(&fl->fl_blocked_requests, &new->fl_blocked_requests);
list_for_each_entry(f, &new->fl_blocked_requests, fl_blocked_member)
f->fl_blocker = new;
spin_unlock(&blocked_lock_lock);
}
static inline int flock_translate_cmd(int cmd) {
switch (cmd) {
case LOCK_SH:
return F_RDLCK;
case LOCK_EX:
return F_WRLCK;
case LOCK_UN:
return F_UNLCK;
}
return -EINVAL;
}
/* Fill in a file_lock structure with an appropriate FLOCK lock. */
static void flock_make_lock(struct file *filp, struct file_lock *fl, int type)
{
locks_init_lock(fl);
fl->fl_file = filp;
fl->fl_owner = filp;
fl->fl_pid = current->tgid;
fl->fl_flags = FL_FLOCK;
fl->fl_type = type;
fl->fl_end = OFFSET_MAX;
}
static int assign_type(struct file_lock *fl, int type)
{
switch (type) {
case F_RDLCK:
case F_WRLCK:
case F_UNLCK:
fl->fl_type = type;
break;
default:
return -EINVAL;
}
return 0;
}
static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
struct flock64 *l)
{
switch (l->l_whence) {
case SEEK_SET:
fl->fl_start = 0;
break;
case SEEK_CUR:
fl->fl_start = filp->f_pos;
break;
case SEEK_END:
fl->fl_start = i_size_read(file_inode(filp));
break;
default:
return -EINVAL;
}
if (l->l_start > OFFSET_MAX - fl->fl_start)
return -EOVERFLOW;
fl->fl_start += l->l_start;
if (fl->fl_start < 0)
return -EINVAL;
/* POSIX-1996 leaves the case l->l_len < 0 undefined;
POSIX-2001 defines it. */
if (l->l_len > 0) {
if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
return -EOVERFLOW;
fl->fl_end = fl->fl_start + (l->l_len - 1);
} else if (l->l_len < 0) {
if (fl->fl_start + l->l_len < 0)
return -EINVAL;
fl->fl_end = fl->fl_start - 1;
fl->fl_start += l->l_len;
} else
fl->fl_end = OFFSET_MAX;
fl->fl_owner = current->files;
fl->fl_pid = current->tgid;
fl->fl_file = filp;
fl->fl_flags = FL_POSIX;
fl->fl_ops = NULL;
fl->fl_lmops = NULL;
return assign_type(fl, l->l_type);
}
/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
* style lock.
*/
static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
struct flock *l)
{
struct flock64 ll = {
.l_type = l->l_type,
.l_whence = l->l_whence,
.l_start = l->l_start,
.l_len = l->l_len,
};
return flock64_to_posix_lock(filp, fl, &ll);
}
/* default lease lock manager operations */
static bool
lease_break_callback(struct file_lock *fl)
{
kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
return false;
}
static void
lease_setup(struct file_lock *fl, void **priv)
{
struct file *filp = fl->fl_file;
struct fasync_struct *fa = *priv;
/*
* fasync_insert_entry() returns the old entry if any. If there was no
* old entry, then it used "priv" and inserted it into the fasync list.
* Clear the pointer to indicate that it shouldn't be freed.
*/
if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
*priv = NULL;
__f_setown(filp, task_pid(current), PIDTYPE_TGID, 0);
}
static const struct lock_manager_operations lease_manager_ops = {
.lm_break = lease_break_callback,
.lm_change = lease_modify,
.lm_setup = lease_setup,
};
/*
* Initialize a lease, use the default lock manager operations
*/
static int lease_init(struct file *filp, int type, struct file_lock *fl)
{
if (assign_type(fl, type) != 0)
return -EINVAL;
fl->fl_owner = filp;
fl->fl_pid = current->tgid;
fl->fl_file = filp;
fl->fl_flags = FL_LEASE;
fl->fl_start = 0;
fl->fl_end = OFFSET_MAX;
fl->fl_ops = NULL;
fl->fl_lmops = &lease_manager_ops;
return 0;
}
/* Allocate a file_lock initialised to this type of lease */
static struct file_lock *lease_alloc(struct file *filp, int type)
{
struct file_lock *fl = locks_alloc_lock();
int error = -ENOMEM;
if (fl == NULL)
return ERR_PTR(error);
error = lease_init(filp, type, fl);
if (error) {
locks_free_lock(fl);
return ERR_PTR(error);
}
return fl;
}
/* Check if two locks overlap each other.
*/
static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
{
return ((fl1->fl_end >= fl2->fl_start) &&
(fl2->fl_end >= fl1->fl_start));
}
/*
* Check whether two locks have the same owner.
*/
static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
{
return fl1->fl_owner == fl2->fl_owner;
}
/* Must be called with the flc_lock held! */
static void locks_insert_global_locks(struct file_lock *fl)
{
struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
percpu_rwsem_assert_held(&file_rwsem);
spin_lock(&fll->lock);
fl->fl_link_cpu = smp_processor_id();
hlist_add_head(&fl->fl_link, &fll->hlist);
spin_unlock(&fll->lock);
}
/* Must be called with the flc_lock held! */
static void locks_delete_global_locks(struct file_lock *fl)
{
struct file_lock_list_struct *fll;
percpu_rwsem_assert_held(&file_rwsem);
/*
* Avoid taking lock if already unhashed. This is safe since this check
* is done while holding the flc_lock, and new insertions into the list
* also require that it be held.
*/
if (hlist_unhashed(&fl->fl_link))
return;
fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu);
spin_lock(&fll->lock);
hlist_del_init(&fl->fl_link);
spin_unlock(&fll->lock);
}
static unsigned long
posix_owner_key(struct file_lock *fl)
{
return (unsigned long)fl->fl_owner;
}
static void locks_insert_global_blocked(struct file_lock *waiter)
{
lockdep_assert_held(&blocked_lock_lock);
hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
}
static void locks_delete_global_blocked(struct file_lock *waiter)
{
lockdep_assert_held(&blocked_lock_lock);
hash_del(&waiter->fl_link);
}
/* Remove waiter from blocker's block list.
* When blocker ends up pointing to itself then the list is empty.
*
* Must be called with blocked_lock_lock held.
*/
static void __locks_delete_block(struct file_lock *waiter)
{
locks_delete_global_blocked(waiter);
list_del_init(&waiter->fl_blocked_member);
}
static void __locks_wake_up_blocks(struct file_lock *blocker)
{
while (!list_empty(&blocker->fl_blocked_requests)) {
struct file_lock *waiter;
waiter = list_first_entry(&blocker->fl_blocked_requests,
struct file_lock, fl_blocked_member);
__locks_delete_block(waiter);
if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
waiter->fl_lmops->lm_notify(waiter);
else
wake_up(&waiter->fl_wait);
/*
* The setting of fl_blocker to NULL marks the "done"
* point in deleting a block. Paired with acquire at the top
* of locks_delete_block().
*/
smp_store_release(&waiter->fl_blocker, NULL);
}
}
/**
* locks_delete_block - stop waiting for a file lock
* @waiter: the lock which was waiting
*
* lockd/nfsd need to disconnect the lock while working on it.
*/
int locks_delete_block(struct file_lock *waiter)
{
int status = -ENOENT;
/*
* If fl_blocker is NULL, it won't be set again as this thread "owns"
* the lock and is the only one that might try to claim the lock.
*
* We use acquire/release to manage fl_blocker so that we can
* optimize away taking the blocked_lock_lock in many cases.
*
* The smp_load_acquire guarantees two things:
*
* 1/ that fl_blocked_requests can be tested locklessly. If something
* was recently added to that list it must have been in a locked region
* *before* the locked region when fl_blocker was set to NULL.
*
* 2/ that no other thread is accessing 'waiter', so it is safe to free
* it. __locks_wake_up_blocks is careful not to touch waiter after
* fl_blocker is released.
*
* If a lockless check of fl_blocker shows it to be NULL, we know that
* no new locks can be inserted into its fl_blocked_requests list, and
* can avoid doing anything further if the list is empty.
*/
if (!smp_load_acquire(&waiter->fl_blocker) &&
list_empty(&waiter->fl_blocked_requests))
return status;
spin_lock(&blocked_lock_lock);
if (waiter->fl_blocker)
status = 0;
__locks_wake_up_blocks(waiter);
__locks_delete_block(waiter);
/*
* The setting of fl_blocker to NULL marks the "done" point in deleting
* a block. Paired with acquire at the top of this function.
*/
smp_store_release(&waiter->fl_blocker, NULL);
spin_unlock(&blocked_lock_lock);
return status;
}
EXPORT_SYMBOL(locks_delete_block);
/* Insert waiter into blocker's block list.
* We use a circular list so that processes can be easily woken up in
* the order they blocked. The documentation doesn't require this but
* it seems like the reasonable thing to do.
*
* Must be called with both the flc_lock and blocked_lock_lock held. The
* fl_blocked_requests list itself is protected by the blocked_lock_lock,
* but by ensuring that the flc_lock is also held on insertions we can avoid
* taking the blocked_lock_lock in some cases when we see that the
* fl_blocked_requests list is empty.
*
* Rather than just adding to the list, we check for conflicts with any existing
* waiters, and add beneath any waiter that blocks the new waiter.
* Thus wakeups don't happen until needed.
*/
static void __locks_insert_block(struct file_lock *blocker,
struct file_lock *waiter,
bool conflict(struct file_lock *,
struct file_lock *))
{
struct file_lock *fl;
BUG_ON(!list_empty(&waiter->fl_blocked_member));
new_blocker:
list_for_each_entry(fl, &blocker->fl_blocked_requests, fl_blocked_member)
if (conflict(fl, waiter)) {
blocker = fl;
goto new_blocker;
}
waiter->fl_blocker = blocker;
list_add_tail(&waiter->fl_blocked_member, &blocker->fl_blocked_requests);
if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
locks_insert_global_blocked(waiter);
/* The requests in waiter->fl_blocked are known to conflict with
* waiter, but might not conflict with blocker, or the requests
* and lock which block it. So they all need to be woken.
*/
__locks_wake_up_blocks(waiter);
}
/* Must be called with flc_lock held. */
static void locks_insert_block(struct file_lock *blocker,
struct file_lock *waiter,
bool conflict(struct file_lock *,
struct file_lock *))
{
spin_lock(&blocked_lock_lock);
__locks_insert_block(blocker, waiter, conflict);
spin_unlock(&blocked_lock_lock);
}
/*
* Wake up processes blocked waiting for blocker.
*
* Must be called with the inode->flc_lock held!
*/
static void locks_wake_up_blocks(struct file_lock *blocker)
{
/*
* Avoid taking global lock if list is empty. This is safe since new
* blocked requests are only added to the list under the flc_lock, and
* the flc_lock is always held here. Note that removal from the
* fl_blocked_requests list does not require the flc_lock, so we must
* recheck list_empty() after acquiring the blocked_lock_lock.
*/
if (list_empty(&blocker->fl_blocked_requests))
return;
spin_lock(&blocked_lock_lock);
__locks_wake_up_blocks(blocker);
spin_unlock(&blocked_lock_lock);
}
static void
locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before)
{
list_add_tail(&fl->fl_list, before);
locks_insert_global_locks(fl);
}
static void
locks_unlink_lock_ctx(struct file_lock *fl)
{
locks_delete_global_locks(fl);
list_del_init(&fl->fl_list);
locks_wake_up_blocks(fl);
}
static void
locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose)
{
locks_unlink_lock_ctx(fl);
if (dispose)
list_add(&fl->fl_list, dispose);
else
locks_free_lock(fl);
}
/* Determine if lock sys_fl blocks lock caller_fl. Common functionality
* checks for shared/exclusive status of overlapping locks.
*/
static bool locks_conflict(struct file_lock *caller_fl,
struct file_lock *sys_fl)
{
if (sys_fl->fl_type == F_WRLCK)
return true;
if (caller_fl->fl_type == F_WRLCK)
return true;
return false;
}
/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
* checking before calling the locks_conflict().
*/
static bool posix_locks_conflict(struct file_lock *caller_fl,
struct file_lock *sys_fl)
{
/* POSIX locks owned by the same process do not conflict with
* each other.
*/
if (posix_same_owner(caller_fl, sys_fl))
return false;
/* Check whether they overlap */
if (!locks_overlap(caller_fl, sys_fl))
return false;
return locks_conflict(caller_fl, sys_fl);
}
/* Determine if lock sys_fl blocks lock caller_fl. Used on xx_GETLK
* path so checks for additional GETLK-specific things like F_UNLCK.
*/
static bool posix_test_locks_conflict(struct file_lock *caller_fl,
struct file_lock *sys_fl)
{
/* F_UNLCK checks any locks on the same fd. */
if (caller_fl->fl_type == F_UNLCK) {
if (!posix_same_owner(caller_fl, sys_fl))
return false;
return locks_overlap(caller_fl, sys_fl);
}
return posix_locks_conflict(caller_fl, sys_fl);
}
/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
* checking before calling the locks_conflict().
*/
static bool flock_locks_conflict(struct file_lock *caller_fl,
struct file_lock *sys_fl)
{
/* FLOCK locks referring to the same filp do not conflict with
* each other.
*/
if (caller_fl->fl_file == sys_fl->fl_file)
return false;
return locks_conflict(caller_fl, sys_fl);
}
void
posix_test_lock(struct file *filp, struct file_lock *fl)
{
struct file_lock *cfl;
struct file_lock_context *ctx;
struct inode *inode = file_inode(filp);
void *owner;
void (*func)(void);
ctx = locks_inode_context(inode);
if (!ctx || list_empty_careful(&ctx->flc_posix)) {
fl->fl_type = F_UNLCK;
return;
}
retry:
spin_lock(&ctx->flc_lock);
list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
if (!posix_test_locks_conflict(fl, cfl))
continue;
if (cfl->fl_lmops && cfl->fl_lmops->lm_lock_expirable
&& (*cfl->fl_lmops->lm_lock_expirable)(cfl)) {
owner = cfl->fl_lmops->lm_mod_owner;
func = cfl->fl_lmops->lm_expire_lock;
__module_get(owner);
spin_unlock(&ctx->flc_lock);
(*func)();
module_put(owner);
goto retry;
}
locks_copy_conflock(fl, cfl);
goto out;
}
fl->fl_type = F_UNLCK;
out:
spin_unlock(&ctx->flc_lock);
return;
}
EXPORT_SYMBOL(posix_test_lock);
/*
* Deadlock detection:
*
* We attempt to detect deadlocks that are due purely to posix file
* locks.
*
* We assume that a task can be waiting for at most one lock at a time.
* So for any acquired lock, the process holding that lock may be
* waiting on at most one other lock. That lock in turns may be held by
* someone waiting for at most one other lock. Given a requested lock
* caller_fl which is about to wait for a conflicting lock block_fl, we
* follow this chain of waiters to ensure we are not about to create a
* cycle.
*
* Since we do this before we ever put a process to sleep on a lock, we
* are ensured that there is never a cycle; that is what guarantees that
* the while() loop in posix_locks_deadlock() eventually completes.
*
* Note: the above assumption may not be true when handling lock
* requests from a broken NFS client. It may also fail in the presence
* of tasks (such as posix threads) sharing the same open file table.
* To handle those cases, we just bail out after a few iterations.
*
* For FL_OFDLCK locks, the owner is the filp, not the files_struct.
* Because the owner is not even nominally tied to a thread of
* execution, the deadlock detection below can't reasonably work well. Just
* skip it for those.
*
* In principle, we could do a more limited deadlock detection on FL_OFDLCK
* locks that just checks for the case where two tasks are attempting to
* upgrade from read to write locks on the same inode.
*/
#define MAX_DEADLK_ITERATIONS 10
/* Find a lock that the owner of the given block_fl is blocking on. */
static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
{
struct file_lock *fl;
hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
if (posix_same_owner(fl, block_fl)) {
while (fl->fl_blocker)
fl = fl->fl_blocker;
return fl;
}
}
return NULL;
}
/* Must be called with the blocked_lock_lock held! */
static int posix_locks_deadlock(struct file_lock *caller_fl,
struct file_lock *block_fl)
{
int i = 0;
lockdep_assert_held(&blocked_lock_lock);
/*
* This deadlock detector can't reasonably detect deadlocks with
* FL_OFDLCK locks, since they aren't owned by a process, per-se.
*/
if (IS_OFDLCK(caller_fl))
return 0;
while ((block_fl = what_owner_is_waiting_for(block_fl))) {
if (i++ > MAX_DEADLK_ITERATIONS)
return 0;
if (posix_same_owner(caller_fl, block_fl))
return 1;
}
return 0;
}
/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
* after any leases, but before any posix locks.
*
* Note that if called with an FL_EXISTS argument, the caller may determine
* whether or not a lock was successfully freed by testing the return
* value for -ENOENT.
*/
static int flock_lock_inode(struct inode *inode, struct file_lock *request)
{
struct file_lock *new_fl = NULL;
struct file_lock *fl;
struct file_lock_context *ctx;
int error = 0;
bool found = false;
LIST_HEAD(dispose);
ctx = locks_get_lock_context(inode, request->fl_type);
if (!ctx) {
if (request->fl_type != F_UNLCK)
return -ENOMEM;
return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0;
}
if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
new_fl = locks_alloc_lock();
if (!new_fl)
return -ENOMEM;
}
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
if (request->fl_flags & FL_ACCESS)
goto find_conflict;
list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
if (request->fl_file != fl->fl_file)
continue;
if (request->fl_type == fl->fl_type)
goto out;
found = true;
locks_delete_lock_ctx(fl, &dispose);
break;
}
if (request->fl_type == F_UNLCK) {
if ((request->fl_flags & FL_EXISTS) && !found)
error = -ENOENT;
goto out;
}
find_conflict:
list_for_each_entry(fl, &ctx->flc_flock, fl_list) {
if (!flock_locks_conflict(request, fl))
continue;
error = -EAGAIN;
if (!(request->fl_flags & FL_SLEEP))
goto out;
error = FILE_LOCK_DEFERRED;
locks_insert_block(fl, request, flock_locks_conflict);
goto out;
}
if (request->fl_flags & FL_ACCESS)
goto out;
locks_copy_lock(new_fl, request);
locks_move_blocks(new_fl, request);
locks_insert_lock_ctx(new_fl, &ctx->flc_flock);
new_fl = NULL;
error = 0;
out:
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
if (new_fl)
locks_free_lock(new_fl);
locks_dispose_list(&dispose);
trace_flock_lock_inode(inode, request, error);
return error;
}
static int posix_lock_inode(struct inode *inode, struct file_lock *request,
struct file_lock *conflock)
{
struct file_lock *fl, *tmp;
struct file_lock *new_fl = NULL;
struct file_lock *new_fl2 = NULL;
struct file_lock *left = NULL;
struct file_lock *right = NULL;
struct file_lock_context *ctx;
int error;
bool added = false;
LIST_HEAD(dispose);
void *owner;
void (*func)(void);
ctx = locks_get_lock_context(inode, request->fl_type);
if (!ctx)
return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM;
/*
* We may need two file_lock structures for this operation,
* so we get them in advance to avoid races.
*
* In some cases we can be sure, that no new locks will be needed
*/
if (!(request->fl_flags & FL_ACCESS) &&
(request->fl_type != F_UNLCK ||
request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
new_fl = locks_alloc_lock();
new_fl2 = locks_alloc_lock();
}
retry:
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
/*
* New lock request. Walk all POSIX locks and look for conflicts. If
* there are any, either return error or put the request on the
* blocker's list of waiters and the global blocked_hash.
*/
if (request->fl_type != F_UNLCK) {
list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
if (!posix_locks_conflict(request, fl))
continue;
if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable
&& (*fl->fl_lmops->lm_lock_expirable)(fl)) {
owner = fl->fl_lmops->lm_mod_owner;
func = fl->fl_lmops->lm_expire_lock;
__module_get(owner);
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
(*func)();
module_put(owner);
goto retry;
}
if (conflock)
locks_copy_conflock(conflock, fl);
error = -EAGAIN;
if (!(request->fl_flags & FL_SLEEP))
goto out;
/*
* Deadlock detection and insertion into the blocked
* locks list must be done while holding the same lock!
*/
error = -EDEADLK;
spin_lock(&blocked_lock_lock);
/*
* Ensure that we don't find any locks blocked on this
* request during deadlock detection.
*/
__locks_wake_up_blocks(request);
if (likely(!posix_locks_deadlock(request, fl))) {
error = FILE_LOCK_DEFERRED;
__locks_insert_block(fl, request,
posix_locks_conflict);
}
spin_unlock(&blocked_lock_lock);
goto out;
}
}
/* If we're just looking for a conflict, we're done. */
error = 0;
if (request->fl_flags & FL_ACCESS)
goto out;
/* Find the first old lock with the same owner as the new lock */
list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
if (posix_same_owner(request, fl))
break;
}
/* Process locks with this owner. */
list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
if (!posix_same_owner(request, fl))
break;
/* Detect adjacent or overlapping regions (if same lock type) */
if (request->fl_type == fl->fl_type) {
/* In all comparisons of start vs end, use
* "start - 1" rather than "end + 1". If end
* is OFFSET_MAX, end + 1 will become negative.
*/
if (fl->fl_end < request->fl_start - 1)
continue;
/* If the next lock in the list has entirely bigger
* addresses than the new one, insert the lock here.
*/
if (fl->fl_start - 1 > request->fl_end)
break;
/* If we come here, the new and old lock are of the
* same type and adjacent or overlapping. Make one
* lock yielding from the lower start address of both
* locks to the higher end address.
*/
if (fl->fl_start > request->fl_start)
fl->fl_start = request->fl_start;
else
request->fl_start = fl->fl_start;
if (fl->fl_end < request->fl_end)
fl->fl_end = request->fl_end;
else
request->fl_end = fl->fl_end;
if (added) {
locks_delete_lock_ctx(fl, &dispose);
continue;
}
request = fl;
added = true;
} else {
/* Processing for different lock types is a bit
* more complex.
*/
if (fl->fl_end < request->fl_start)
continue;
if (fl->fl_start > request->fl_end)
break;
if (request->fl_type == F_UNLCK)
added = true;
if (fl->fl_start < request->fl_start)
left = fl;
/* If the next lock in the list has a higher end
* address than the new one, insert the new one here.
*/
if (fl->fl_end > request->fl_end) {
right = fl;
break;
}
if (fl->fl_start >= request->fl_start) {
/* The new lock completely replaces an old
* one (This may happen several times).
*/
if (added) {
locks_delete_lock_ctx(fl, &dispose);
continue;
}
/*
* Replace the old lock with new_fl, and
* remove the old one. It's safe to do the
* insert here since we know that we won't be
* using new_fl later, and that the lock is
* just replacing an existing lock.
*/
error = -ENOLCK;
if (!new_fl)
goto out;
locks_copy_lock(new_fl, request);
locks_move_blocks(new_fl, request);
request = new_fl;
new_fl = NULL;
locks_insert_lock_ctx(request, &fl->fl_list);
locks_delete_lock_ctx(fl, &dispose);
added = true;
}
}
}
/*
* The above code only modifies existing locks in case of merging or
* replacing. If new lock(s) need to be inserted all modifications are
* done below this, so it's safe yet to bail out.
*/
error = -ENOLCK; /* "no luck" */
if (right && left == right && !new_fl2)
goto out;
error = 0;
if (!added) {
if (request->fl_type == F_UNLCK) {
if (request->fl_flags & FL_EXISTS)
error = -ENOENT;
goto out;
}
if (!new_fl) {
error = -ENOLCK;
goto out;
}
locks_copy_lock(new_fl, request);
locks_move_blocks(new_fl, request);
locks_insert_lock_ctx(new_fl, &fl->fl_list);
fl = new_fl;
new_fl = NULL;
}
if (right) {
if (left == right) {
/* The new lock breaks the old one in two pieces,
* so we have to use the second new lock.
*/
left = new_fl2;
new_fl2 = NULL;
locks_copy_lock(left, right);
locks_insert_lock_ctx(left, &fl->fl_list);
}
right->fl_start = request->fl_end + 1;
locks_wake_up_blocks(right);
}
if (left) {
left->fl_end = request->fl_start - 1;
locks_wake_up_blocks(left);
}
out:
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
trace_posix_lock_inode(inode, request, error);
/*
* Free any unused locks.
*/
if (new_fl)
locks_free_lock(new_fl);
if (new_fl2)
locks_free_lock(new_fl2);
locks_dispose_list(&dispose);
return error;
}
/**
* posix_lock_file - Apply a POSIX-style lock to a file
* @filp: The file to apply the lock to
* @fl: The lock to be applied
* @conflock: Place to return a copy of the conflicting lock, if found.
*
* Add a POSIX style lock to a file.
* We merge adjacent & overlapping locks whenever possible.
* POSIX locks are sorted by owner task, then by starting address
*
* Note that if called with an FL_EXISTS argument, the caller may determine
* whether or not a lock was successfully freed by testing the return
* value for -ENOENT.
*/
int posix_lock_file(struct file *filp, struct file_lock *fl,
struct file_lock *conflock)
{
return posix_lock_inode(file_inode(filp), fl, conflock);
}
EXPORT_SYMBOL(posix_lock_file);
/**
* posix_lock_inode_wait - Apply a POSIX-style lock to a file
* @inode: inode of file to which lock request should be applied
* @fl: The lock to be applied
*
* Apply a POSIX style lock request to an inode.
*/
static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
{
int error;
might_sleep ();
for (;;) {
error = posix_lock_inode(inode, fl, NULL);
if (error != FILE_LOCK_DEFERRED)
break;
error = wait_event_interruptible(fl->fl_wait,
list_empty(&fl->fl_blocked_member));
if (error)
break;
}
locks_delete_block(fl);
return error;
}
static void lease_clear_pending(struct file_lock *fl, int arg)
{
switch (arg) {
case F_UNLCK:
fl->fl_flags &= ~FL_UNLOCK_PENDING;
fallthrough;
case F_RDLCK:
fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
}
}
/* We already had a lease on this file; just change its type */
int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose)
{
int error = assign_type(fl, arg);
if (error)
return error;
lease_clear_pending(fl, arg);
locks_wake_up_blocks(fl);
if (arg == F_UNLCK) {
struct file *filp = fl->fl_file;
f_delown(filp);
filp->f_owner.signum = 0;
fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
if (fl->fl_fasync != NULL) {
printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
fl->fl_fasync = NULL;
}
locks_delete_lock_ctx(fl, dispose);
}
return 0;
}
EXPORT_SYMBOL(lease_modify);
static bool past_time(unsigned long then)
{
if (!then)
/* 0 is a special value meaning "this never expires": */
return false;
return time_after(jiffies, then);
}
static void time_out_leases(struct inode *inode, struct list_head *dispose)
{
struct file_lock_context *ctx = inode->i_flctx;
struct file_lock *fl, *tmp;
lockdep_assert_held(&ctx->flc_lock);
list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
trace_time_out_leases(inode, fl);
if (past_time(fl->fl_downgrade_time))
lease_modify(fl, F_RDLCK, dispose);
if (past_time(fl->fl_break_time))
lease_modify(fl, F_UNLCK, dispose);
}
}
static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
{
bool rc;
if (lease->fl_lmops->lm_breaker_owns_lease
&& lease->fl_lmops->lm_breaker_owns_lease(lease))
return false;
if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT)) {
rc = false;
goto trace;
}
if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) {
rc = false;
goto trace;
}
rc = locks_conflict(breaker, lease);
trace:
trace_leases_conflict(rc, lease, breaker);
return rc;
}
static bool
any_leases_conflict(struct inode *inode, struct file_lock *breaker)
{
struct file_lock_context *ctx = inode->i_flctx;
struct file_lock *fl;
lockdep_assert_held(&ctx->flc_lock);
list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
if (leases_conflict(fl, breaker))
return true;
}
return false;
}
/**
* __break_lease - revoke all outstanding leases on file
* @inode: the inode of the file to return
* @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
* break all leases
* @type: FL_LEASE: break leases and delegations; FL_DELEG: break
* only delegations
*
* break_lease (inlined for speed) has checked there already is at least
* some kind of lock (maybe a lease) on this file. Leases are broken on
* a call to open() or truncate(). This function can sleep unless you
* specified %O_NONBLOCK to your open().
*/
int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
{
int error = 0;
struct file_lock_context *ctx;
struct file_lock *new_fl, *fl, *tmp;
unsigned long break_time;
int want_write = (mode & O_ACCMODE) != O_RDONLY;
LIST_HEAD(dispose);
new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
if (IS_ERR(new_fl))
return PTR_ERR(new_fl);
new_fl->fl_flags = type;
/* typically we will check that ctx is non-NULL before calling */
ctx = locks_inode_context(inode);
if (!ctx) {
WARN_ON_ONCE(1);
goto free_lock;
}
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
time_out_leases(inode, &dispose);
if (!any_leases_conflict(inode, new_fl))
goto out;
break_time = 0;
if (lease_break_time > 0) {
break_time = jiffies + lease_break_time * HZ;
if (break_time == 0)
break_time++; /* so that 0 means no break time */
}
list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) {
if (!leases_conflict(fl, new_fl))
continue;
if (want_write) {
if (fl->fl_flags & FL_UNLOCK_PENDING)
continue;
fl->fl_flags |= FL_UNLOCK_PENDING;
fl->fl_break_time = break_time;
} else {
if (lease_breaking(fl))
continue;
fl->fl_flags |= FL_DOWNGRADE_PENDING;
fl->fl_downgrade_time = break_time;
}
if (fl->fl_lmops->lm_break(fl))
locks_delete_lock_ctx(fl, &dispose);
}
if (list_empty(&ctx->flc_lease))
goto out;
if (mode & O_NONBLOCK) {
trace_break_lease_noblock(inode, new_fl);
error = -EWOULDBLOCK;
goto out;
}
restart:
fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list);
break_time = fl->fl_break_time;
if (break_time != 0)
break_time -= jiffies;
if (break_time == 0)
break_time++;
locks_insert_block(fl, new_fl, leases_conflict);
trace_break_lease_block(inode, new_fl);
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
locks_dispose_list(&dispose);
error = wait_event_interruptible_timeout(new_fl->fl_wait,
list_empty(&new_fl->fl_blocked_member),
break_time);
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
trace_break_lease_unblock(inode, new_fl);
locks_delete_block(new_fl);
if (error >= 0) {
/*
* Wait for the next conflicting lease that has not been
* broken yet
*/
if (error == 0)
time_out_leases(inode, &dispose);
if (any_leases_conflict(inode, new_fl))
goto restart;
error = 0;
}
out:
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
locks_dispose_list(&dispose);
free_lock:
locks_free_lock(new_fl);
return error;
}
EXPORT_SYMBOL(__break_lease);
/**
* lease_get_mtime - update modified time of an inode with exclusive lease
* @inode: the inode
* @time: pointer to a timespec which contains the last modified time
*
* This is to force NFS clients to flush their caches for files with
* exclusive leases. The justification is that if someone has an
* exclusive lease, then they could be modifying it.
*/
void lease_get_mtime(struct inode *inode, struct timespec64 *time)
{
bool has_lease = false;
struct file_lock_context *ctx;
struct file_lock *fl;
ctx = locks_inode_context(inode);
if (ctx && !list_empty_careful(&ctx->flc_lease)) {
spin_lock(&ctx->flc_lock);
fl = list_first_entry_or_null(&ctx->flc_lease,
struct file_lock, fl_list);
if (fl && (fl->fl_type == F_WRLCK))
has_lease = true;
spin_unlock(&ctx->flc_lock);
}
if (has_lease)
*time = current_time(inode);
}
EXPORT_SYMBOL(lease_get_mtime);
/**
* fcntl_getlease - Enquire what lease is currently active
* @filp: the file
*
* The value returned by this function will be one of
* (if no lease break is pending):
*
* %F_RDLCK to indicate a shared lease is held.
*
* %F_WRLCK to indicate an exclusive lease is held.
*
* %F_UNLCK to indicate no lease is held.
*
* (if a lease break is pending):
*
* %F_RDLCK to indicate an exclusive lease needs to be
* changed to a shared lease (or removed).
*
* %F_UNLCK to indicate the lease needs to be removed.
*
* XXX: sfr & willy disagree over whether F_INPROGRESS
* should be returned to userspace.
*/
int fcntl_getlease(struct file *filp)
{
struct file_lock *fl;
struct inode *inode = file_inode(filp);
struct file_lock_context *ctx;
int type = F_UNLCK;
LIST_HEAD(dispose);
ctx = locks_inode_context(inode);
if (ctx && !list_empty_careful(&ctx->flc_lease)) {
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
time_out_leases(inode, &dispose);
list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
if (fl->fl_file != filp)
continue;
type = target_leasetype(fl);
break;
}
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
locks_dispose_list(&dispose);
}
return type;
}
/**
* check_conflicting_open - see if the given file points to an inode that has
* an existing open that would conflict with the
* desired lease.
* @filp: file to check
* @arg: type of lease that we're trying to acquire
* @flags: current lock flags
*
* Check to see if there's an existing open fd on this file that would
* conflict with the lease we're trying to set.
*/
static int
check_conflicting_open(struct file *filp, const int arg, int flags)
{
struct inode *inode = file_inode(filp);
int self_wcount = 0, self_rcount = 0;
if (flags & FL_LAYOUT)
return 0;
if (flags & FL_DELEG)
/* We leave these checks to the caller */
return 0;
if (arg == F_RDLCK)
return inode_is_open_for_write(inode) ? -EAGAIN : 0;
else if (arg != F_WRLCK)
return 0;
/*
* Make sure that only read/write count is from lease requestor.
* Note that this will result in denying write leases when i_writecount
* is negative, which is what we want. (We shouldn't grant write leases
* on files open for execution.)
*/
if (filp->f_mode & FMODE_WRITE)
self_wcount = 1;
else if (filp->f_mode & FMODE_READ)
self_rcount = 1;
if (atomic_read(&inode->i_writecount) != self_wcount ||
atomic_read(&inode->i_readcount) != self_rcount)
return -EAGAIN;
return 0;
}
static int
generic_add_lease(struct file *filp, int arg, struct file_lock **flp, void **priv)
{
struct file_lock *fl, *my_fl = NULL, *lease;
struct inode *inode = file_inode(filp);
struct file_lock_context *ctx;
bool is_deleg = (*flp)->fl_flags & FL_DELEG;
int error;
LIST_HEAD(dispose);
lease = *flp;
trace_generic_add_lease(inode, lease);
/* Note that arg is never F_UNLCK here */
ctx = locks_get_lock_context(inode, arg);
if (!ctx)
return -ENOMEM;
/*
* In the delegation case we need mutual exclusion with
* a number of operations that take the i_mutex. We trylock
* because delegations are an optional optimization, and if
* there's some chance of a conflict--we'd rather not
* bother, maybe that's a sign this just isn't a good file to
* hand out a delegation on.
*/
if (is_deleg && !inode_trylock(inode))
return -EAGAIN;
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
time_out_leases(inode, &dispose);
error = check_conflicting_open(filp, arg, lease->fl_flags);
if (error)
goto out;
/*
* At this point, we know that if there is an exclusive
* lease on this file, then we hold it on this filp
* (otherwise our open of this file would have blocked).
* And if we are trying to acquire an exclusive lease,
* then the file is not open by anyone (including us)
* except for this filp.
*/
error = -EAGAIN;
list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
if (fl->fl_file == filp &&
fl->fl_owner == lease->fl_owner) {
my_fl = fl;
continue;
}
/*
* No exclusive leases if someone else has a lease on
* this file:
*/
if (arg == F_WRLCK)
goto out;
/*
* Modifying our existing lease is OK, but no getting a
* new lease if someone else is opening for write:
*/
if (fl->fl_flags & FL_UNLOCK_PENDING)
goto out;
}
if (my_fl != NULL) {
lease = my_fl;
error = lease->fl_lmops->lm_change(lease, arg, &dispose);
if (error)
goto out;
goto out_setup;
}
error = -EINVAL;
if (!leases_enable)
goto out;
locks_insert_lock_ctx(lease, &ctx->flc_lease);
/*
* The check in break_lease() is lockless. It's possible for another
* open to race in after we did the earlier check for a conflicting
* open but before the lease was inserted. Check again for a
* conflicting open and cancel the lease if there is one.
*
* We also add a barrier here to ensure that the insertion of the lock
* precedes these checks.
*/
smp_mb();
error = check_conflicting_open(filp, arg, lease->fl_flags);
if (error) {
locks_unlink_lock_ctx(lease);
goto out;
}
out_setup:
if (lease->fl_lmops->lm_setup)
lease->fl_lmops->lm_setup(lease, priv);
out:
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
locks_dispose_list(&dispose);
if (is_deleg)
inode_unlock(inode);
if (!error && !my_fl)
*flp = NULL;
return error;
}
static int generic_delete_lease(struct file *filp, void *owner)
{
int error = -EAGAIN;
struct file_lock *fl, *victim = NULL;
struct inode *inode = file_inode(filp);
struct file_lock_context *ctx;
LIST_HEAD(dispose);
ctx = locks_inode_context(inode);
if (!ctx) {
trace_generic_delete_lease(inode, NULL);
return error;
}
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
if (fl->fl_file == filp &&
fl->fl_owner == owner) {
victim = fl;
break;
}
}
trace_generic_delete_lease(inode, victim);
if (victim)
error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
locks_dispose_list(&dispose);
return error;
}
/**
* generic_setlease - sets a lease on an open file
* @filp: file pointer
* @arg: type of lease to obtain
* @flp: input - file_lock to use, output - file_lock inserted
* @priv: private data for lm_setup (may be NULL if lm_setup
* doesn't require it)
*
* The (input) flp->fl_lmops->lm_break function is required
* by break_lease().
*/
int generic_setlease(struct file *filp, int arg, struct file_lock **flp,
void **priv)
{
struct inode *inode = file_inode(filp);
vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(filp), inode);
int error;
if ((!vfsuid_eq_kuid(vfsuid, current_fsuid())) && !capable(CAP_LEASE))
return -EACCES;
if (!S_ISREG(inode->i_mode))
return -EINVAL;
error = security_file_lock(filp, arg);
if (error)
return error;
switch (arg) {
case F_UNLCK:
return generic_delete_lease(filp, *priv);
case F_RDLCK:
case F_WRLCK:
if (!(*flp)->fl_lmops->lm_break) {
WARN_ON_ONCE(1);
return -ENOLCK;
}
return generic_add_lease(filp, arg, flp, priv);
default:
return -EINVAL;
}
}
EXPORT_SYMBOL(generic_setlease);
/*
* Kernel subsystems can register to be notified on any attempt to set
* a new lease with the lease_notifier_chain. This is used by (e.g.) nfsd
* to close files that it may have cached when there is an attempt to set a
* conflicting lease.
*/
static struct srcu_notifier_head lease_notifier_chain;
static inline void
lease_notifier_chain_init(void)
{
srcu_init_notifier_head(&lease_notifier_chain);
}
static inline void
setlease_notifier(int arg, struct file_lock *lease)
{
if (arg != F_UNLCK)
srcu_notifier_call_chain(&lease_notifier_chain, arg, lease);
}
int lease_register_notifier(struct notifier_block *nb)
{
return srcu_notifier_chain_register(&lease_notifier_chain, nb);
}
EXPORT_SYMBOL_GPL(lease_register_notifier);
void lease_unregister_notifier(struct notifier_block *nb)
{
srcu_notifier_chain_unregister(&lease_notifier_chain, nb);
}
EXPORT_SYMBOL_GPL(lease_unregister_notifier);
/**
* vfs_setlease - sets a lease on an open file
* @filp: file pointer
* @arg: type of lease to obtain
* @lease: file_lock to use when adding a lease
* @priv: private info for lm_setup when adding a lease (may be
* NULL if lm_setup doesn't require it)
*
* Call this to establish a lease on the file. The "lease" argument is not
* used for F_UNLCK requests and may be NULL. For commands that set or alter
* an existing lease, the ``(*lease)->fl_lmops->lm_break`` operation must be
* set; if not, this function will return -ENOLCK (and generate a scary-looking
* stack trace).
*
* The "priv" pointer is passed directly to the lm_setup function as-is. It
* may be NULL if the lm_setup operation doesn't require it.
*/
int
vfs_setlease(struct file *filp, int arg, struct file_lock **lease, void **priv)
{
if (lease)
setlease_notifier(arg, *lease);
if (filp->f_op->setlease)
return filp->f_op->setlease(filp, arg, lease, priv);
else
return generic_setlease(filp, arg, lease, priv);
}
EXPORT_SYMBOL_GPL(vfs_setlease);
static int do_fcntl_add_lease(unsigned int fd, struct file *filp, int arg)
{
struct file_lock *fl;
struct fasync_struct *new;
int error;
fl = lease_alloc(filp, arg);
if (IS_ERR(fl))
return PTR_ERR(fl);
new = fasync_alloc();
if (!new) {
locks_free_lock(fl);
return -ENOMEM;
}
new->fa_fd = fd;
error = vfs_setlease(filp, arg, &fl, (void **)&new);
if (fl)
locks_free_lock(fl);
if (new)
fasync_free(new);
return error;
}
/**
* fcntl_setlease - sets a lease on an open file
* @fd: open file descriptor
* @filp: file pointer
* @arg: type of lease to obtain
*
* Call this fcntl to establish a lease on the file.
* Note that you also need to call %F_SETSIG to
* receive a signal when the lease is broken.
*/
int fcntl_setlease(unsigned int fd, struct file *filp, int arg)
{
if (arg == F_UNLCK)
return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
return do_fcntl_add_lease(fd, filp, arg);
}
/**
* flock_lock_inode_wait - Apply a FLOCK-style lock to a file
* @inode: inode of the file to apply to
* @fl: The lock to be applied
*
* Apply a FLOCK style lock request to an inode.
*/
static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
{
int error;
might_sleep();
for (;;) {
error = flock_lock_inode(inode, fl);
if (error != FILE_LOCK_DEFERRED)
break;
error = wait_event_interruptible(fl->fl_wait,
list_empty(&fl->fl_blocked_member));
if (error)
break;
}
locks_delete_block(fl);
return error;
}
/**
* locks_lock_inode_wait - Apply a lock to an inode
* @inode: inode of the file to apply to
* @fl: The lock to be applied
*
* Apply a POSIX or FLOCK style lock request to an inode.
*/
int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
{
int res = 0;
switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
case FL_POSIX:
res = posix_lock_inode_wait(inode, fl);
break;
case FL_FLOCK:
res = flock_lock_inode_wait(inode, fl);
break;
default:
BUG();
}
return res;
}
EXPORT_SYMBOL(locks_lock_inode_wait);
/**
* sys_flock: - flock() system call.
* @fd: the file descriptor to lock.
* @cmd: the type of lock to apply.
*
* Apply a %FL_FLOCK style lock to an open file descriptor.
* The @cmd can be one of:
*
* - %LOCK_SH -- a shared lock.
* - %LOCK_EX -- an exclusive lock.
* - %LOCK_UN -- remove an existing lock.
* - %LOCK_MAND -- a 'mandatory' flock. (DEPRECATED)
*
* %LOCK_MAND support has been removed from the kernel.
*/
SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
{
int can_sleep, error, type;
struct file_lock fl;
struct fd f;
/*
* LOCK_MAND locks were broken for a long time in that they never
* conflicted with one another and didn't prevent any sort of open,
* read or write activity.
*
* Just ignore these requests now, to preserve legacy behavior, but
* throw a warning to let people know that they don't actually work.
*/
if (cmd & LOCK_MAND) {
pr_warn_once("%s(%d): Attempt to set a LOCK_MAND lock via flock(2). This support has been removed and the request ignored.\n", current->comm, current->pid);
return 0;
}
type = flock_translate_cmd(cmd & ~LOCK_NB);
if (type < 0)
return type;
error = -EBADF;
f = fdget(fd);
if (!f.file)
return error;
if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ | FMODE_WRITE)))
goto out_putf;
flock_make_lock(f.file, &fl, type);
error = security_file_lock(f.file, fl.fl_type);
if (error)
goto out_putf;
can_sleep = !(cmd & LOCK_NB);
if (can_sleep)
fl.fl_flags |= FL_SLEEP;
if (f.file->f_op->flock)
error = f.file->f_op->flock(f.file,
(can_sleep) ? F_SETLKW : F_SETLK,
&fl);
else
error = locks_lock_file_wait(f.file, &fl);
locks_release_private(&fl);
out_putf:
fdput(f);
return error;
}
/**
* vfs_test_lock - test file byte range lock
* @filp: The file to test lock for
* @fl: The lock to test; also used to hold result
*
* Returns -ERRNO on failure. Indicates presence of conflicting lock by
* setting conf->fl_type to something other than F_UNLCK.
*/
int vfs_test_lock(struct file *filp, struct file_lock *fl)
{
WARN_ON_ONCE(filp != fl->fl_file);
if (filp->f_op->lock)
return filp->f_op->lock(filp, F_GETLK, fl);
posix_test_lock(filp, fl);
return 0;
}
EXPORT_SYMBOL_GPL(vfs_test_lock);
/**
* locks_translate_pid - translate a file_lock's fl_pid number into a namespace
* @fl: The file_lock who's fl_pid should be translated
* @ns: The namespace into which the pid should be translated
*
* Used to translate a fl_pid into a namespace virtual pid number
*/
static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns)
{
pid_t vnr;
struct pid *pid;
if (IS_OFDLCK(fl))
return -1;
if (IS_REMOTELCK(fl))
return fl->fl_pid;
/*
* If the flock owner process is dead and its pid has been already
* freed, the translation below won't work, but we still want to show
* flock owner pid number in init pidns.
*/
if (ns == &init_pid_ns)
return (pid_t)fl->fl_pid;
rcu_read_lock();
pid = find_pid_ns(fl->fl_pid, &init_pid_ns);
vnr = pid_nr_ns(pid, ns);
rcu_read_unlock();
return vnr;
}
static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
{
flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
#if BITS_PER_LONG == 32
/*
* Make sure we can represent the posix lock via
* legacy 32bit flock.
*/
if (fl->fl_start > OFFT_OFFSET_MAX)
return -EOVERFLOW;
if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
return -EOVERFLOW;
#endif
flock->l_start = fl->fl_start;
flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
fl->fl_end - fl->fl_start + 1;
flock->l_whence = 0;
flock->l_type = fl->fl_type;
return 0;
}
#if BITS_PER_LONG == 32
static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
{
flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current));
flock->l_start = fl->fl_start;
flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
fl->fl_end - fl->fl_start + 1;
flock->l_whence = 0;
flock->l_type = fl->fl_type;
}
#endif
/* Report the first existing lock that would conflict with l.
* This implements the F_GETLK command of fcntl().
*/
int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
{
struct file_lock *fl;
int error;
fl = locks_alloc_lock();
if (fl == NULL)
return -ENOMEM;
error = -EINVAL;
if (cmd != F_OFD_GETLK && flock->l_type != F_RDLCK
&& flock->l_type != F_WRLCK)
goto out;
error = flock_to_posix_lock(filp, fl, flock);
if (error)
goto out;
if (cmd == F_OFD_GETLK) {
error = -EINVAL;
if (flock->l_pid != 0)
goto out;
fl->fl_flags |= FL_OFDLCK;
fl->fl_owner = filp;
}
error = vfs_test_lock(filp, fl);
if (error)
goto out;
flock->l_type = fl->fl_type;
if (fl->fl_type != F_UNLCK) {
error = posix_lock_to_flock(flock, fl);
if (error)
goto out;
}
out:
locks_free_lock(fl);
return error;
}
/**
* vfs_lock_file - file byte range lock
* @filp: The file to apply the lock to
* @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
* @fl: The lock to be applied
* @conf: Place to return a copy of the conflicting lock, if found.
*
* A caller that doesn't care about the conflicting lock may pass NULL
* as the final argument.
*
* If the filesystem defines a private ->lock() method, then @conf will
* be left unchanged; so a caller that cares should initialize it to
* some acceptable default.
*
* To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
* locks, the ->lock() interface may return asynchronously, before the lock has
* been granted or denied by the underlying filesystem, if (and only if)
* lm_grant is set. Callers expecting ->lock() to return asynchronously
* will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
* the request is for a blocking lock. When ->lock() does return asynchronously,
* it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
* request completes.
* If the request is for non-blocking lock the file system should return
* FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
* with the result. If the request timed out the callback routine will return a
* nonzero return code and the file system should release the lock. The file
* system is also responsible to keep a corresponding posix lock when it
* grants a lock so the VFS can find out which locks are locally held and do
* the correct lock cleanup when required.
* The underlying filesystem must not drop the kernel lock or call
* ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
* return code.
*/
int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
{
WARN_ON_ONCE(filp != fl->fl_file);
if (filp->f_op->lock)
return filp->f_op->lock(filp, cmd, fl);
else
return posix_lock_file(filp, fl, conf);
}
EXPORT_SYMBOL_GPL(vfs_lock_file);
static int do_lock_file_wait(struct file *filp, unsigned int cmd,
struct file_lock *fl)
{
int error;
error = security_file_lock(filp, fl->fl_type);
if (error)
return error;
for (;;) {
error = vfs_lock_file(filp, cmd, fl, NULL);
if (error != FILE_LOCK_DEFERRED)
break;
error = wait_event_interruptible(fl->fl_wait,
list_empty(&fl->fl_blocked_member));
if (error)
break;
}
locks_delete_block(fl);
return error;
}
/* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */
static int
check_fmode_for_setlk(struct file_lock *fl)
{
switch (fl->fl_type) {
case F_RDLCK:
if (!(fl->fl_file->f_mode & FMODE_READ))
return -EBADF;
break;
case F_WRLCK:
if (!(fl->fl_file->f_mode & FMODE_WRITE))
return -EBADF;
}
return 0;
}
/* Apply the lock described by l to an open file descriptor.
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
struct flock *flock)
{
struct file_lock *file_lock = locks_alloc_lock();
struct inode *inode = file_inode(filp);
struct file *f;
int error;
if (file_lock == NULL)
return -ENOLCK;
error = flock_to_posix_lock(filp, file_lock, flock);
if (error)
goto out;
error = check_fmode_for_setlk(file_lock);
if (error)
goto out;
/*
* If the cmd is requesting file-private locks, then set the
* FL_OFDLCK flag and override the owner.
*/
switch (cmd) {
case F_OFD_SETLK:
error = -EINVAL;
if (flock->l_pid != 0)
goto out;
cmd = F_SETLK;
file_lock->fl_flags |= FL_OFDLCK;
file_lock->fl_owner = filp;
break;
case F_OFD_SETLKW:
error = -EINVAL;
if (flock->l_pid != 0)
goto out;
cmd = F_SETLKW;
file_lock->fl_flags |= FL_OFDLCK;
file_lock->fl_owner = filp;
fallthrough;
case F_SETLKW:
file_lock->fl_flags |= FL_SLEEP;
}
error = do_lock_file_wait(filp, cmd, file_lock);
/*
* Attempt to detect a close/fcntl race and recover by releasing the
* lock that was just acquired. There is no need to do that when we're
* unlocking though, or for OFD locks.
*/
if (!error && file_lock->fl_type != F_UNLCK &&
!(file_lock->fl_flags & FL_OFDLCK)) {
struct files_struct *files = current->files;
/*
* We need that spin_lock here - it prevents reordering between
* update of i_flctx->flc_posix and check for it done in
* close(). rcu_read_lock() wouldn't do.
*/
spin_lock(&files->file_lock);
f = files_lookup_fd_locked(files, fd);
spin_unlock(&files->file_lock);
if (f != filp) {
file_lock->fl_type = F_UNLCK;
error = do_lock_file_wait(filp, cmd, file_lock);
WARN_ON_ONCE(error);
error = -EBADF;
}
}
out:
trace_fcntl_setlk(inode, file_lock, error);
locks_free_lock(file_lock);
return error;
}
#if BITS_PER_LONG == 32
/* Report the first existing lock that would conflict with l.
* This implements the F_GETLK command of fcntl().
*/
int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
{
struct file_lock *fl;
int error;
fl = locks_alloc_lock();
if (fl == NULL)
return -ENOMEM;
error = -EINVAL;
if (cmd != F_OFD_GETLK && flock->l_type != F_RDLCK
&& flock->l_type != F_WRLCK)
goto out;
error = flock64_to_posix_lock(filp, fl, flock);
if (error)
goto out;
if (cmd == F_OFD_GETLK) {
error = -EINVAL;
if (flock->l_pid != 0)
goto out;
fl->fl_flags |= FL_OFDLCK;
fl->fl_owner = filp;
}
error = vfs_test_lock(filp, fl);
if (error)
goto out;
flock->l_type = fl->fl_type;
if (fl->fl_type != F_UNLCK)
posix_lock_to_flock64(flock, fl);
out:
locks_free_lock(fl);
return error;
}
/* Apply the lock described by l to an open file descriptor.
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
struct flock64 *flock)
{
struct file_lock *file_lock = locks_alloc_lock();
struct file *f;
int error;
if (file_lock == NULL)
return -ENOLCK;
error = flock64_to_posix_lock(filp, file_lock, flock);
if (error)
goto out;
error = check_fmode_for_setlk(file_lock);
if (error)
goto out;
/*
* If the cmd is requesting file-private locks, then set the
* FL_OFDLCK flag and override the owner.
*/
switch (cmd) {
case F_OFD_SETLK:
error = -EINVAL;
if (flock->l_pid != 0)
goto out;
cmd = F_SETLK64;
file_lock->fl_flags |= FL_OFDLCK;
file_lock->fl_owner = filp;
break;
case F_OFD_SETLKW:
error = -EINVAL;
if (flock->l_pid != 0)
goto out;
cmd = F_SETLKW64;
file_lock->fl_flags |= FL_OFDLCK;
file_lock->fl_owner = filp;
fallthrough;
case F_SETLKW64:
file_lock->fl_flags |= FL_SLEEP;
}
error = do_lock_file_wait(filp, cmd, file_lock);
/*
* Attempt to detect a close/fcntl race and recover by releasing the
* lock that was just acquired. There is no need to do that when we're
* unlocking though, or for OFD locks.
*/
if (!error && file_lock->fl_type != F_UNLCK &&
!(file_lock->fl_flags & FL_OFDLCK)) {
struct files_struct *files = current->files;
/*
* We need that spin_lock here - it prevents reordering between
* update of i_flctx->flc_posix and check for it done in
* close(). rcu_read_lock() wouldn't do.
*/
spin_lock(&files->file_lock);
f = files_lookup_fd_locked(files, fd);
spin_unlock(&files->file_lock);
if (f != filp) {
file_lock->fl_type = F_UNLCK;
error = do_lock_file_wait(filp, cmd, file_lock);
WARN_ON_ONCE(error);
error = -EBADF;
}
}
out:
locks_free_lock(file_lock);
return error;
}
#endif /* BITS_PER_LONG == 32 */
/*
* This function is called when the file is being removed
* from the task's fd array. POSIX locks belonging to this task
* are deleted at this time.
*/
void locks_remove_posix(struct file *filp, fl_owner_t owner)
{
int error;
struct inode *inode = file_inode(filp);
struct file_lock lock;
struct file_lock_context *ctx;
/*
* If there are no locks held on this file, we don't need to call
* posix_lock_file(). Another process could be setting a lock on this
* file at the same time, but we wouldn't remove that lock anyway.
*/
ctx = locks_inode_context(inode);
if (!ctx || list_empty(&ctx->flc_posix))
return;
locks_init_lock(&lock);
lock.fl_type = F_UNLCK;
lock.fl_flags = FL_POSIX | FL_CLOSE;
lock.fl_start = 0;
lock.fl_end = OFFSET_MAX;
lock.fl_owner = owner;
lock.fl_pid = current->tgid;
lock.fl_file = filp;
lock.fl_ops = NULL;
lock.fl_lmops = NULL;
error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
if (lock.fl_ops && lock.fl_ops->fl_release_private)
lock.fl_ops->fl_release_private(&lock);
trace_locks_remove_posix(inode, &lock, error);
}
EXPORT_SYMBOL(locks_remove_posix);
/* The i_flctx must be valid when calling into here */
static void
locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
{
struct file_lock fl;
struct inode *inode = file_inode(filp);
if (list_empty(&flctx->flc_flock))
return;
flock_make_lock(filp, &fl, F_UNLCK);
fl.fl_flags |= FL_CLOSE;
if (filp->f_op->flock)
filp->f_op->flock(filp, F_SETLKW, &fl);
else
flock_lock_inode(inode, &fl);
if (fl.fl_ops && fl.fl_ops->fl_release_private)
fl.fl_ops->fl_release_private(&fl);
}
/* The i_flctx must be valid when calling into here */
static void
locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
{
struct file_lock *fl, *tmp;
LIST_HEAD(dispose);
if (list_empty(&ctx->flc_lease))
return;
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
if (filp == fl->fl_file)
lease_modify(fl, F_UNLCK, &dispose);
spin_unlock(&ctx->flc_lock);
percpu_up_read(&file_rwsem);
locks_dispose_list(&dispose);
}
/*
* This function is called on the last close of an open file.
*/
void locks_remove_file(struct file *filp)
{
struct file_lock_context *ctx;
ctx = locks_inode_context(file_inode(filp));
if (!ctx)
return;
/* remove any OFD locks */
locks_remove_posix(filp, filp);
/* remove flock locks */
locks_remove_flock(filp, ctx);
/* remove any leases */
locks_remove_lease(filp, ctx);
spin_lock(&ctx->flc_lock);
locks_check_ctx_file_list(filp, &ctx->flc_posix, "POSIX");
locks_check_ctx_file_list(filp, &ctx->flc_flock, "FLOCK");
locks_check_ctx_file_list(filp, &ctx->flc_lease, "LEASE");
spin_unlock(&ctx->flc_lock);
}
/**
* vfs_cancel_lock - file byte range unblock lock
* @filp: The file to apply the unblock to
* @fl: The lock to be unblocked
*
* Used by lock managers to cancel blocked requests
*/
int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
{
WARN_ON_ONCE(filp != fl->fl_file);
if (filp->f_op->lock)
return filp->f_op->lock(filp, F_CANCELLK, fl);
return 0;
}
EXPORT_SYMBOL_GPL(vfs_cancel_lock);
/**
* vfs_inode_has_locks - are any file locks held on @inode?
* @inode: inode to check for locks
*
* Return true if there are any FL_POSIX or FL_FLOCK locks currently
* set on @inode.
*/
bool vfs_inode_has_locks(struct inode *inode)
{
struct file_lock_context *ctx;
bool ret;
ctx = locks_inode_context(inode);
if (!ctx)
return false;
spin_lock(&ctx->flc_lock);
ret = !list_empty(&ctx->flc_posix) || !list_empty(&ctx->flc_flock);
spin_unlock(&ctx->flc_lock);
return ret;
}
EXPORT_SYMBOL_GPL(vfs_inode_has_locks);
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
struct locks_iterator {
int li_cpu;
loff_t li_pos;
};
static void lock_get_status(struct seq_file *f, struct file_lock *fl,
loff_t id, char *pfx, int repeat)
{
struct inode *inode = NULL;
unsigned int fl_pid;
struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
int type;
fl_pid = locks_translate_pid(fl, proc_pidns);
/*
* If lock owner is dead (and pid is freed) or not visible in current
* pidns, zero is shown as a pid value. Check lock info from
* init_pid_ns to get saved lock pid value.
*/
if (fl->fl_file != NULL)
inode = file_inode(fl->fl_file);
seq_printf(f, "%lld: ", id);
if (repeat)
seq_printf(f, "%*s", repeat - 1 + (int)strlen(pfx), pfx);
if (IS_POSIX(fl)) {
if (fl->fl_flags & FL_ACCESS)
seq_puts(f, "ACCESS");
else if (IS_OFDLCK(fl))
seq_puts(f, "OFDLCK");
else
seq_puts(f, "POSIX ");
seq_printf(f, " %s ",
(inode == NULL) ? "*NOINODE*" : "ADVISORY ");
} else if (IS_FLOCK(fl)) {
seq_puts(f, "FLOCK ADVISORY ");
} else if (IS_LEASE(fl)) {
if (fl->fl_flags & FL_DELEG)
seq_puts(f, "DELEG ");
else
seq_puts(f, "LEASE ");
if (lease_breaking(fl))
seq_puts(f, "BREAKING ");
else if (fl->fl_file)
seq_puts(f, "ACTIVE ");
else
seq_puts(f, "BREAKER ");
} else {
seq_puts(f, "UNKNOWN UNKNOWN ");
}
type = IS_LEASE(fl) ? target_leasetype(fl) : fl->fl_type;
seq_printf(f, "%s ", (type == F_WRLCK) ? "WRITE" :
(type == F_RDLCK) ? "READ" : "UNLCK");
if (inode) {
/* userspace relies on this representation of dev_t */
seq_printf(f, "%d %02x:%02x:%lu ", fl_pid,
MAJOR(inode->i_sb->s_dev),
MINOR(inode->i_sb->s_dev), inode->i_ino);
} else {
seq_printf(f, "%d <none>:0 ", fl_pid);
}
if (IS_POSIX(fl)) {
if (fl->fl_end == OFFSET_MAX)
seq_printf(f, "%Ld EOF\n", fl->fl_start);
else
seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
} else {
seq_puts(f, "0 EOF\n");
}
}
static struct file_lock *get_next_blocked_member(struct file_lock *node)
{
struct file_lock *tmp;
/* NULL node or root node */
if (node == NULL || node->fl_blocker == NULL)
return NULL;
/* Next member in the linked list could be itself */
tmp = list_next_entry(node, fl_blocked_member);
if (list_entry_is_head(tmp, &node->fl_blocker->fl_blocked_requests, fl_blocked_member)
|| tmp == node) {
return NULL;
}
return tmp;
}
static int locks_show(struct seq_file *f, void *v)
{
struct locks_iterator *iter = f->private;
struct file_lock *cur, *tmp;
struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
int level = 0;
cur = hlist_entry(v, struct file_lock, fl_link);
if (locks_translate_pid(cur, proc_pidns) == 0)
return 0;
/* View this crossed linked list as a binary tree, the first member of fl_blocked_requests
* is the left child of current node, the next silibing in fl_blocked_member is the
* right child, we can alse get the parent of current node from fl_blocker, so this
* question becomes traversal of a binary tree
*/
while (cur != NULL) {
if (level)
lock_get_status(f, cur, iter->li_pos, "-> ", level);
else
lock_get_status(f, cur, iter->li_pos, "", level);
if (!list_empty(&cur->fl_blocked_requests)) {
/* Turn left */
cur = list_first_entry_or_null(&cur->fl_blocked_requests,
struct file_lock, fl_blocked_member);
level++;
} else {
/* Turn right */
tmp = get_next_blocked_member(cur);
/* Fall back to parent node */
while (tmp == NULL && cur->fl_blocker != NULL) {
cur = cur->fl_blocker;
level--;
tmp = get_next_blocked_member(cur);
}
cur = tmp;
}
}
return 0;
}
static void __show_fd_locks(struct seq_file *f,
struct list_head *head, int *id,
struct file *filp, struct files_struct *files)
{
struct file_lock *fl;
list_for_each_entry(fl, head, fl_list) {
if (filp != fl->fl_file)
continue;
if (fl->fl_owner != files &&
fl->fl_owner != filp)
continue;
(*id)++;
seq_puts(f, "lock:\t");
lock_get_status(f, fl, *id, "", 0);
}
}
void show_fd_locks(struct seq_file *f,
struct file *filp, struct files_struct *files)
{
struct inode *inode = file_inode(filp);
struct file_lock_context *ctx;
int id = 0;
ctx = locks_inode_context(inode);
if (!ctx)
return;
spin_lock(&ctx->flc_lock);
__show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
__show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
__show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
spin_unlock(&ctx->flc_lock);
}
static void *locks_start(struct seq_file *f, loff_t *pos)
__acquires(&blocked_lock_lock)
{
struct locks_iterator *iter = f->private;
iter->li_pos = *pos + 1;
percpu_down_write(&file_rwsem);
spin_lock(&blocked_lock_lock);
return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
}
static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
{
struct locks_iterator *iter = f->private;
++iter->li_pos;
return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
}
static void locks_stop(struct seq_file *f, void *v)
__releases(&blocked_lock_lock)
{
spin_unlock(&blocked_lock_lock);
percpu_up_write(&file_rwsem);
}
static const struct seq_operations locks_seq_operations = {
.start = locks_start,
.next = locks_next,
.stop = locks_stop,
.show = locks_show,
};
static int __init proc_locks_init(void)
{
proc_create_seq_private("locks", 0, NULL, &locks_seq_operations,
sizeof(struct locks_iterator), NULL);
return 0;
}
fs_initcall(proc_locks_init);
#endif
static int __init filelock_init(void)
{
int i;
flctx_cache = kmem_cache_create("file_lock_ctx",
sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
filelock_cache = kmem_cache_create("file_lock_cache",
sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
for_each_possible_cpu(i) {
struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
spin_lock_init(&fll->lock);
INIT_HLIST_HEAD(&fll->hlist);
}
lease_notifier_chain_init();
return 0;
}
core_initcall(filelock_init);
| linux-master | fs/locks.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <kunit/test.h>
static void total_mapping_size_test(struct kunit *test)
{
struct elf_phdr empty[] = {
{ .p_type = PT_LOAD, .p_vaddr = 0, .p_memsz = 0, },
{ .p_type = PT_INTERP, .p_vaddr = 10, .p_memsz = 999999, },
};
/*
* readelf -lW /bin/mount | grep '^ .*0x0' | awk '{print "\t\t{ .p_type = PT_" \
* $1 ", .p_vaddr = " $3 ", .p_memsz = " $6 ", },"}'
*/
struct elf_phdr mount[] = {
{ .p_type = PT_PHDR, .p_vaddr = 0x00000040, .p_memsz = 0x0002d8, },
{ .p_type = PT_INTERP, .p_vaddr = 0x00000318, .p_memsz = 0x00001c, },
{ .p_type = PT_LOAD, .p_vaddr = 0x00000000, .p_memsz = 0x0033a8, },
{ .p_type = PT_LOAD, .p_vaddr = 0x00004000, .p_memsz = 0x005c91, },
{ .p_type = PT_LOAD, .p_vaddr = 0x0000a000, .p_memsz = 0x0022f8, },
{ .p_type = PT_LOAD, .p_vaddr = 0x0000d330, .p_memsz = 0x000d40, },
{ .p_type = PT_DYNAMIC, .p_vaddr = 0x0000d928, .p_memsz = 0x000200, },
{ .p_type = PT_NOTE, .p_vaddr = 0x00000338, .p_memsz = 0x000030, },
{ .p_type = PT_NOTE, .p_vaddr = 0x00000368, .p_memsz = 0x000044, },
{ .p_type = PT_GNU_PROPERTY, .p_vaddr = 0x00000338, .p_memsz = 0x000030, },
{ .p_type = PT_GNU_EH_FRAME, .p_vaddr = 0x0000b490, .p_memsz = 0x0001ec, },
{ .p_type = PT_GNU_STACK, .p_vaddr = 0x00000000, .p_memsz = 0x000000, },
{ .p_type = PT_GNU_RELRO, .p_vaddr = 0x0000d330, .p_memsz = 0x000cd0, },
};
size_t mount_size = 0xE070;
/* https://lore.kernel.org/linux-fsdevel/[email protected] */
struct elf_phdr unordered[] = {
{ .p_type = PT_LOAD, .p_vaddr = 0x00000000, .p_memsz = 0x0033a8, },
{ .p_type = PT_LOAD, .p_vaddr = 0x0000d330, .p_memsz = 0x000d40, },
{ .p_type = PT_LOAD, .p_vaddr = 0x00004000, .p_memsz = 0x005c91, },
{ .p_type = PT_LOAD, .p_vaddr = 0x0000a000, .p_memsz = 0x0022f8, },
};
/* No headers, no size. */
KUNIT_EXPECT_EQ(test, total_mapping_size(NULL, 0), 0);
KUNIT_EXPECT_EQ(test, total_mapping_size(empty, 0), 0);
/* Empty headers, no size. */
KUNIT_EXPECT_EQ(test, total_mapping_size(empty, 1), 0);
/* No PT_LOAD headers, no size. */
KUNIT_EXPECT_EQ(test, total_mapping_size(&empty[1], 1), 0);
/* Empty PT_LOAD and non-PT_LOAD headers, no size. */
KUNIT_EXPECT_EQ(test, total_mapping_size(empty, 2), 0);
/* Normal set of PT_LOADS, and expected size. */
KUNIT_EXPECT_EQ(test, total_mapping_size(mount, ARRAY_SIZE(mount)), mount_size);
/* Unordered PT_LOADs result in same size. */
KUNIT_EXPECT_EQ(test, total_mapping_size(unordered, ARRAY_SIZE(unordered)), mount_size);
}
static struct kunit_case binfmt_elf_test_cases[] = {
KUNIT_CASE(total_mapping_size_test),
{},
};
static struct kunit_suite binfmt_elf_test_suite = {
.name = KBUILD_MODNAME,
.test_cases = binfmt_elf_test_cases,
};
kunit_test_suite(binfmt_elf_test_suite);
| linux-master | fs/binfmt_elf_test.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/filesystems.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* table of configured filesystems
*/
#include <linux/syscalls.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/fs_parser.h>
/*
* Handling of filesystem drivers list.
* Rules:
* Inclusion to/removals from/scanning of list are protected by spinlock.
* During the unload module must call unregister_filesystem().
* We can access the fields of list element if:
* 1) spinlock is held or
* 2) we hold the reference to the module.
* The latter can be guaranteed by call of try_module_get(); if it
* returned 0 we must skip the element, otherwise we got the reference.
* Once the reference is obtained we can drop the spinlock.
*/
static struct file_system_type *file_systems;
static DEFINE_RWLOCK(file_systems_lock);
/* WARNING: This can be used only if we _already_ own a reference */
struct file_system_type *get_filesystem(struct file_system_type *fs)
{
__module_get(fs->owner);
return fs;
}
void put_filesystem(struct file_system_type *fs)
{
module_put(fs->owner);
}
static struct file_system_type **find_filesystem(const char *name, unsigned len)
{
struct file_system_type **p;
for (p = &file_systems; *p; p = &(*p)->next)
if (strncmp((*p)->name, name, len) == 0 &&
!(*p)->name[len])
break;
return p;
}
/**
* register_filesystem - register a new filesystem
* @fs: the file system structure
*
* Adds the file system passed to the list of file systems the kernel
* is aware of for mount and other syscalls. Returns 0 on success,
* or a negative errno code on an error.
*
* The &struct file_system_type that is passed is linked into the kernel
* structures and must not be freed until the file system has been
* unregistered.
*/
int register_filesystem(struct file_system_type * fs)
{
int res = 0;
struct file_system_type ** p;
if (fs->parameters &&
!fs_validate_description(fs->name, fs->parameters))
return -EINVAL;
BUG_ON(strchr(fs->name, '.'));
if (fs->next)
return -EBUSY;
write_lock(&file_systems_lock);
p = find_filesystem(fs->name, strlen(fs->name));
if (*p)
res = -EBUSY;
else
*p = fs;
write_unlock(&file_systems_lock);
return res;
}
EXPORT_SYMBOL(register_filesystem);
/**
* unregister_filesystem - unregister a file system
* @fs: filesystem to unregister
*
* Remove a file system that was previously successfully registered
* with the kernel. An error is returned if the file system is not found.
* Zero is returned on a success.
*
* Once this function has returned the &struct file_system_type structure
* may be freed or reused.
*/
int unregister_filesystem(struct file_system_type * fs)
{
struct file_system_type ** tmp;
write_lock(&file_systems_lock);
tmp = &file_systems;
while (*tmp) {
if (fs == *tmp) {
*tmp = fs->next;
fs->next = NULL;
write_unlock(&file_systems_lock);
synchronize_rcu();
return 0;
}
tmp = &(*tmp)->next;
}
write_unlock(&file_systems_lock);
return -EINVAL;
}
EXPORT_SYMBOL(unregister_filesystem);
#ifdef CONFIG_SYSFS_SYSCALL
static int fs_index(const char __user * __name)
{
struct file_system_type * tmp;
struct filename *name;
int err, index;
name = getname(__name);
err = PTR_ERR(name);
if (IS_ERR(name))
return err;
err = -EINVAL;
read_lock(&file_systems_lock);
for (tmp=file_systems, index=0 ; tmp ; tmp=tmp->next, index++) {
if (strcmp(tmp->name, name->name) == 0) {
err = index;
break;
}
}
read_unlock(&file_systems_lock);
putname(name);
return err;
}
static int fs_name(unsigned int index, char __user * buf)
{
struct file_system_type * tmp;
int len, res;
read_lock(&file_systems_lock);
for (tmp = file_systems; tmp; tmp = tmp->next, index--)
if (index <= 0 && try_module_get(tmp->owner))
break;
read_unlock(&file_systems_lock);
if (!tmp)
return -EINVAL;
/* OK, we got the reference, so we can safely block */
len = strlen(tmp->name) + 1;
res = copy_to_user(buf, tmp->name, len) ? -EFAULT : 0;
put_filesystem(tmp);
return res;
}
static int fs_maxindex(void)
{
struct file_system_type * tmp;
int index;
read_lock(&file_systems_lock);
for (tmp = file_systems, index = 0 ; tmp ; tmp = tmp->next, index++)
;
read_unlock(&file_systems_lock);
return index;
}
/*
* Whee.. Weird sysv syscall.
*/
SYSCALL_DEFINE3(sysfs, int, option, unsigned long, arg1, unsigned long, arg2)
{
int retval = -EINVAL;
switch (option) {
case 1:
retval = fs_index((const char __user *) arg1);
break;
case 2:
retval = fs_name(arg1, (char __user *) arg2);
break;
case 3:
retval = fs_maxindex();
break;
}
return retval;
}
#endif
int __init list_bdev_fs_names(char *buf, size_t size)
{
struct file_system_type *p;
size_t len;
int count = 0;
read_lock(&file_systems_lock);
for (p = file_systems; p; p = p->next) {
if (!(p->fs_flags & FS_REQUIRES_DEV))
continue;
len = strlen(p->name) + 1;
if (len > size) {
pr_warn("%s: truncating file system list\n", __func__);
break;
}
memcpy(buf, p->name, len);
buf += len;
size -= len;
count++;
}
read_unlock(&file_systems_lock);
return count;
}
#ifdef CONFIG_PROC_FS
static int filesystems_proc_show(struct seq_file *m, void *v)
{
struct file_system_type * tmp;
read_lock(&file_systems_lock);
tmp = file_systems;
while (tmp) {
seq_printf(m, "%s\t%s\n",
(tmp->fs_flags & FS_REQUIRES_DEV) ? "" : "nodev",
tmp->name);
tmp = tmp->next;
}
read_unlock(&file_systems_lock);
return 0;
}
static int __init proc_filesystems_init(void)
{
proc_create_single("filesystems", 0, NULL, filesystems_proc_show);
return 0;
}
module_init(proc_filesystems_init);
#endif
static struct file_system_type *__get_fs_type(const char *name, int len)
{
struct file_system_type *fs;
read_lock(&file_systems_lock);
fs = *(find_filesystem(name, len));
if (fs && !try_module_get(fs->owner))
fs = NULL;
read_unlock(&file_systems_lock);
return fs;
}
struct file_system_type *get_fs_type(const char *name)
{
struct file_system_type *fs;
const char *dot = strchr(name, '.');
int len = dot ? dot - name : strlen(name);
fs = __get_fs_type(name, len);
if (!fs && (request_module("fs-%.*s", len, name) == 0)) {
fs = __get_fs_type(name, len);
if (!fs)
pr_warn_once("request_module fs-%.*s succeeded, but still no fs?\n",
len, name);
}
if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) {
put_filesystem(fs);
fs = NULL;
}
return fs;
}
EXPORT_SYMBOL(get_fs_type);
| linux-master | fs/filesystems.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/attr.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
* changes by Thomas Schoebel-Theuer
*/
#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/sched/signal.h>
#include <linux/capability.h>
#include <linux/fsnotify.h>
#include <linux/fcntl.h>
#include <linux/filelock.h>
#include <linux/security.h>
#include <linux/evm.h>
#include <linux/ima.h>
#include "internal.h"
/**
* setattr_should_drop_sgid - determine whether the setgid bit needs to be
* removed
* @idmap: idmap of the mount @inode was found from
* @inode: inode to check
*
* This function determines whether the setgid bit needs to be removed.
* We retain backwards compatibility and require setgid bit to be removed
* unconditionally if S_IXGRP is set. Otherwise we have the exact same
* requirements as setattr_prepare() and setattr_copy().
*
* Return: ATTR_KILL_SGID if setgid bit needs to be removed, 0 otherwise.
*/
int setattr_should_drop_sgid(struct mnt_idmap *idmap,
const struct inode *inode)
{
umode_t mode = inode->i_mode;
if (!(mode & S_ISGID))
return 0;
if (mode & S_IXGRP)
return ATTR_KILL_SGID;
if (!in_group_or_capable(idmap, inode, i_gid_into_vfsgid(idmap, inode)))
return ATTR_KILL_SGID;
return 0;
}
EXPORT_SYMBOL(setattr_should_drop_sgid);
/**
* setattr_should_drop_suidgid - determine whether the set{g,u}id bit needs to
* be dropped
* @idmap: idmap of the mount @inode was found from
* @inode: inode to check
*
* This function determines whether the set{g,u}id bits need to be removed.
* If the setuid bit needs to be removed ATTR_KILL_SUID is returned. If the
* setgid bit needs to be removed ATTR_KILL_SGID is returned. If both
* set{g,u}id bits need to be removed the corresponding mask of both flags is
* returned.
*
* Return: A mask of ATTR_KILL_S{G,U}ID indicating which - if any - setid bits
* to remove, 0 otherwise.
*/
int setattr_should_drop_suidgid(struct mnt_idmap *idmap,
struct inode *inode)
{
umode_t mode = inode->i_mode;
int kill = 0;
/* suid always must be killed */
if (unlikely(mode & S_ISUID))
kill = ATTR_KILL_SUID;
kill |= setattr_should_drop_sgid(idmap, inode);
if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
return kill;
return 0;
}
EXPORT_SYMBOL(setattr_should_drop_suidgid);
/**
* chown_ok - verify permissions to chown inode
* @idmap: idmap of the mount @inode was found from
* @inode: inode to check permissions on
* @ia_vfsuid: uid to chown @inode to
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before checking
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply pass @nop_mnt_idmap.
*/
static bool chown_ok(struct mnt_idmap *idmap,
const struct inode *inode, vfsuid_t ia_vfsuid)
{
vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
if (vfsuid_eq_kuid(vfsuid, current_fsuid()) &&
vfsuid_eq(ia_vfsuid, vfsuid))
return true;
if (capable_wrt_inode_uidgid(idmap, inode, CAP_CHOWN))
return true;
if (!vfsuid_valid(vfsuid) &&
ns_capable(inode->i_sb->s_user_ns, CAP_CHOWN))
return true;
return false;
}
/**
* chgrp_ok - verify permissions to chgrp inode
* @idmap: idmap of the mount @inode was found from
* @inode: inode to check permissions on
* @ia_vfsgid: gid to chown @inode to
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before checking
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply pass @nop_mnt_idmap.
*/
static bool chgrp_ok(struct mnt_idmap *idmap,
const struct inode *inode, vfsgid_t ia_vfsgid)
{
vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
if (vfsuid_eq_kuid(vfsuid, current_fsuid())) {
if (vfsgid_eq(ia_vfsgid, vfsgid))
return true;
if (vfsgid_in_group_p(ia_vfsgid))
return true;
}
if (capable_wrt_inode_uidgid(idmap, inode, CAP_CHOWN))
return true;
if (!vfsgid_valid(vfsgid) &&
ns_capable(inode->i_sb->s_user_ns, CAP_CHOWN))
return true;
return false;
}
/**
* setattr_prepare - check if attribute changes to a dentry are allowed
* @idmap: idmap of the mount the inode was found from
* @dentry: dentry to check
* @attr: attributes to change
*
* Check if we are allowed to change the attributes contained in @attr
* in the given dentry. This includes the normal unix access permission
* checks, as well as checks for rlimits and others. The function also clears
* SGID bit from mode if user is not allowed to set it. Also file capabilities
* and IMA extended attributes are cleared if ATTR_KILL_PRIV is set.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before checking
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply passs @nop_mnt_idmap.
*
* Should be called as the first thing in ->setattr implementations,
* possibly after taking additional locks.
*/
int setattr_prepare(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
unsigned int ia_valid = attr->ia_valid;
/*
* First check size constraints. These can't be overriden using
* ATTR_FORCE.
*/
if (ia_valid & ATTR_SIZE) {
int error = inode_newsize_ok(inode, attr->ia_size);
if (error)
return error;
}
/* If force is set do it anyway. */
if (ia_valid & ATTR_FORCE)
goto kill_priv;
/* Make sure a caller can chown. */
if ((ia_valid & ATTR_UID) &&
!chown_ok(idmap, inode, attr->ia_vfsuid))
return -EPERM;
/* Make sure caller can chgrp. */
if ((ia_valid & ATTR_GID) &&
!chgrp_ok(idmap, inode, attr->ia_vfsgid))
return -EPERM;
/* Make sure a caller can chmod. */
if (ia_valid & ATTR_MODE) {
vfsgid_t vfsgid;
if (!inode_owner_or_capable(idmap, inode))
return -EPERM;
if (ia_valid & ATTR_GID)
vfsgid = attr->ia_vfsgid;
else
vfsgid = i_gid_into_vfsgid(idmap, inode);
/* Also check the setgid bit! */
if (!in_group_or_capable(idmap, inode, vfsgid))
attr->ia_mode &= ~S_ISGID;
}
/* Check for setting the inode time. */
if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
if (!inode_owner_or_capable(idmap, inode))
return -EPERM;
}
kill_priv:
/* User has permission for the change */
if (ia_valid & ATTR_KILL_PRIV) {
int error;
error = security_inode_killpriv(idmap, dentry);
if (error)
return error;
}
return 0;
}
EXPORT_SYMBOL(setattr_prepare);
/**
* inode_newsize_ok - may this inode be truncated to a given size
* @inode: the inode to be truncated
* @offset: the new size to assign to the inode
*
* inode_newsize_ok must be called with i_mutex held.
*
* inode_newsize_ok will check filesystem limits and ulimits to check that the
* new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
* when necessary. Caller must not proceed with inode size change if failure is
* returned. @inode must be a file (not directory), with appropriate
* permissions to allow truncate (inode_newsize_ok does NOT check these
* conditions).
*
* Return: 0 on success, -ve errno on failure
*/
int inode_newsize_ok(const struct inode *inode, loff_t offset)
{
if (offset < 0)
return -EINVAL;
if (inode->i_size < offset) {
unsigned long limit;
limit = rlimit(RLIMIT_FSIZE);
if (limit != RLIM_INFINITY && offset > limit)
goto out_sig;
if (offset > inode->i_sb->s_maxbytes)
goto out_big;
} else {
/*
* truncation of in-use swapfiles is disallowed - it would
* cause subsequent swapout to scribble on the now-freed
* blocks.
*/
if (IS_SWAPFILE(inode))
return -ETXTBSY;
}
return 0;
out_sig:
send_sig(SIGXFSZ, current, 0);
out_big:
return -EFBIG;
}
EXPORT_SYMBOL(inode_newsize_ok);
/**
* setattr_copy - copy simple metadata updates into the generic inode
* @idmap: idmap of the mount the inode was found from
* @inode: the inode to be updated
* @attr: the new attributes
*
* setattr_copy must be called with i_mutex held.
*
* setattr_copy updates the inode's metadata with that specified
* in attr on idmapped mounts. Necessary permission checks to determine
* whether or not the S_ISGID property needs to be removed are performed with
* the correct idmapped mount permission helpers.
* Noticeably missing is inode size update, which is more complex
* as it requires pagecache updates.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before checking
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply pass @nop_mnt_idmap.
*
* The inode is not marked as dirty after this operation. The rationale is
* that for "simple" filesystems, the struct inode is the inode storage.
* The caller is free to mark the inode dirty afterwards if needed.
*/
void setattr_copy(struct mnt_idmap *idmap, struct inode *inode,
const struct iattr *attr)
{
unsigned int ia_valid = attr->ia_valid;
i_uid_update(idmap, attr, inode);
i_gid_update(idmap, attr, inode);
if (ia_valid & ATTR_ATIME)
inode->i_atime = attr->ia_atime;
if (ia_valid & ATTR_MTIME)
inode->i_mtime = attr->ia_mtime;
if (ia_valid & ATTR_CTIME)
inode_set_ctime_to_ts(inode, attr->ia_ctime);
if (ia_valid & ATTR_MODE) {
umode_t mode = attr->ia_mode;
if (!in_group_or_capable(idmap, inode,
i_gid_into_vfsgid(idmap, inode)))
mode &= ~S_ISGID;
inode->i_mode = mode;
}
}
EXPORT_SYMBOL(setattr_copy);
int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
unsigned int ia_valid)
{
int error;
if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
return -EPERM;
}
/*
* If utimes(2) and friends are called with times == NULL (or both
* times are UTIME_NOW), then we need to check for write permission
*/
if (ia_valid & ATTR_TOUCH) {
if (IS_IMMUTABLE(inode))
return -EPERM;
if (!inode_owner_or_capable(idmap, inode)) {
error = inode_permission(idmap, inode, MAY_WRITE);
if (error)
return error;
}
}
return 0;
}
EXPORT_SYMBOL(may_setattr);
/**
* notify_change - modify attributes of a filesytem object
* @idmap: idmap of the mount the inode was found from
* @dentry: object affected
* @attr: new attributes
* @delegated_inode: returns inode, if the inode is delegated
*
* The caller must hold the i_mutex on the affected object.
*
* If notify_change discovers a delegation in need of breaking,
* it will return -EWOULDBLOCK and return a reference to the inode in
* delegated_inode. The caller should then break the delegation and
* retry. Because breaking a delegation may take a long time, the
* caller should drop the i_mutex before doing so.
*
* Alternatively, a caller may pass NULL for delegated_inode. This may
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported. Also, passing NULL is fine for callers holding
* the file open for write, as there can be no conflicting delegation in
* that case.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before checking
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply pass @nop_mnt_idmap.
*/
int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr, struct inode **delegated_inode)
{
struct inode *inode = dentry->d_inode;
umode_t mode = inode->i_mode;
int error;
struct timespec64 now;
unsigned int ia_valid = attr->ia_valid;
WARN_ON_ONCE(!inode_is_locked(inode));
error = may_setattr(idmap, inode, ia_valid);
if (error)
return error;
if ((ia_valid & ATTR_MODE)) {
/*
* Don't allow changing the mode of symlinks:
*
* (1) The vfs doesn't take the mode of symlinks into account
* during permission checking.
* (2) This has never worked correctly. Most major filesystems
* did return EOPNOTSUPP due to interactions with POSIX ACLs
* but did still updated the mode of the symlink.
* This inconsistency led system call wrapper providers such
* as libc to block changing the mode of symlinks with
* EOPNOTSUPP already.
* (3) To even do this in the first place one would have to use
* specific file descriptors and quite some effort.
*/
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
/* Flag setting protected by i_mutex */
if (is_sxid(attr->ia_mode))
inode->i_flags &= ~S_NOSEC;
}
now = current_time(inode);
attr->ia_ctime = now;
if (!(ia_valid & ATTR_ATIME_SET))
attr->ia_atime = now;
else
attr->ia_atime = timestamp_truncate(attr->ia_atime, inode);
if (!(ia_valid & ATTR_MTIME_SET))
attr->ia_mtime = now;
else
attr->ia_mtime = timestamp_truncate(attr->ia_mtime, inode);
if (ia_valid & ATTR_KILL_PRIV) {
error = security_inode_need_killpriv(dentry);
if (error < 0)
return error;
if (error == 0)
ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
}
/*
* We now pass ATTR_KILL_S*ID to the lower level setattr function so
* that the function has the ability to reinterpret a mode change
* that's due to these bits. This adds an implicit restriction that
* no function will ever call notify_change with both ATTR_MODE and
* ATTR_KILL_S*ID set.
*/
if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
(ia_valid & ATTR_MODE))
BUG();
if (ia_valid & ATTR_KILL_SUID) {
if (mode & S_ISUID) {
ia_valid = attr->ia_valid |= ATTR_MODE;
attr->ia_mode = (inode->i_mode & ~S_ISUID);
}
}
if (ia_valid & ATTR_KILL_SGID) {
if (mode & S_ISGID) {
if (!(ia_valid & ATTR_MODE)) {
ia_valid = attr->ia_valid |= ATTR_MODE;
attr->ia_mode = inode->i_mode;
}
attr->ia_mode &= ~S_ISGID;
}
}
if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
return 0;
/*
* Verify that uid/gid changes are valid in the target
* namespace of the superblock.
*/
if (ia_valid & ATTR_UID &&
!vfsuid_has_fsmapping(idmap, inode->i_sb->s_user_ns,
attr->ia_vfsuid))
return -EOVERFLOW;
if (ia_valid & ATTR_GID &&
!vfsgid_has_fsmapping(idmap, inode->i_sb->s_user_ns,
attr->ia_vfsgid))
return -EOVERFLOW;
/* Don't allow modifications of files with invalid uids or
* gids unless those uids & gids are being made valid.
*/
if (!(ia_valid & ATTR_UID) &&
!vfsuid_valid(i_uid_into_vfsuid(idmap, inode)))
return -EOVERFLOW;
if (!(ia_valid & ATTR_GID) &&
!vfsgid_valid(i_gid_into_vfsgid(idmap, inode)))
return -EOVERFLOW;
error = security_inode_setattr(idmap, dentry, attr);
if (error)
return error;
error = try_break_deleg(inode, delegated_inode);
if (error)
return error;
if (inode->i_op->setattr)
error = inode->i_op->setattr(idmap, dentry, attr);
else
error = simple_setattr(idmap, dentry, attr);
if (!error) {
fsnotify_change(dentry, ia_valid);
ima_inode_post_setattr(idmap, dentry);
evm_inode_post_setattr(dentry, ia_valid);
}
return error;
}
EXPORT_SYMBOL(notify_change);
| linux-master | fs/attr.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Implement the manual drop-all-pagecache function
*/
#include <linux/pagemap.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/writeback.h>
#include <linux/sysctl.h>
#include <linux/gfp.h>
#include <linux/swap.h>
#include "internal.h"
/* A global variable is a bit ugly, but it keeps the code simple */
int sysctl_drop_caches;
static void drop_pagecache_sb(struct super_block *sb, void *unused)
{
struct inode *inode, *toput_inode = NULL;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
/*
* We must skip inodes in unusual state. We may also skip
* inodes without pages but we deliberately won't in case
* we need to reschedule to avoid softlockups.
*/
if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
(mapping_empty(inode->i_mapping) && !need_resched())) {
spin_unlock(&inode->i_lock);
continue;
}
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inode_list_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
toput_inode = inode;
cond_resched();
spin_lock(&sb->s_inode_list_lock);
}
spin_unlock(&sb->s_inode_list_lock);
iput(toput_inode);
}
int drop_caches_sysctl_handler(struct ctl_table *table, int write,
void *buffer, size_t *length, loff_t *ppos)
{
int ret;
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (ret)
return ret;
if (write) {
static int stfu;
if (sysctl_drop_caches & 1) {
lru_add_drain_all();
iterate_supers(drop_pagecache_sb, NULL);
count_vm_event(DROP_PAGECACHE);
}
if (sysctl_drop_caches & 2) {
drop_slab();
count_vm_event(DROP_SLAB);
}
if (!stfu) {
pr_info("%s (%d): drop_caches: %d\n",
current->comm, task_pid_nr(current),
sysctl_drop_caches);
}
stfu |= sysctl_drop_caches & 4;
}
return 0;
}
| linux-master | fs/drop_caches.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* (C) 1997 Linus Torvalds
* (C) 1999 Andrea Arcangeli <[email protected]> (dynamic inode allocation)
*/
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include <linux/hash.h>
#include <linux/swap.h>
#include <linux/security.h>
#include <linux/cdev.h>
#include <linux/memblock.h>
#include <linux/fsnotify.h>
#include <linux/mount.h>
#include <linux/posix_acl.h>
#include <linux/buffer_head.h> /* for inode_has_buffers */
#include <linux/ratelimit.h>
#include <linux/list_lru.h>
#include <linux/iversion.h>
#include <trace/events/writeback.h>
#include "internal.h"
/*
* Inode locking rules:
*
* inode->i_lock protects:
* inode->i_state, inode->i_hash, __iget(), inode->i_io_list
* Inode LRU list locks protect:
* inode->i_sb->s_inode_lru, inode->i_lru
* inode->i_sb->s_inode_list_lock protects:
* inode->i_sb->s_inodes, inode->i_sb_list
* bdi->wb.list_lock protects:
* bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list
* inode_hash_lock protects:
* inode_hashtable, inode->i_hash
*
* Lock ordering:
*
* inode->i_sb->s_inode_list_lock
* inode->i_lock
* Inode LRU list locks
*
* bdi->wb.list_lock
* inode->i_lock
*
* inode_hash_lock
* inode->i_sb->s_inode_list_lock
* inode->i_lock
*
* iunique_lock
* inode_hash_lock
*/
static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
static struct hlist_head *inode_hashtable __read_mostly;
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
/*
* Empty aops. Can be used for the cases where the user does not
* define any of the address_space operations.
*/
const struct address_space_operations empty_aops = {
};
EXPORT_SYMBOL(empty_aops);
static DEFINE_PER_CPU(unsigned long, nr_inodes);
static DEFINE_PER_CPU(unsigned long, nr_unused);
static struct kmem_cache *inode_cachep __read_mostly;
static long get_nr_inodes(void)
{
int i;
long sum = 0;
for_each_possible_cpu(i)
sum += per_cpu(nr_inodes, i);
return sum < 0 ? 0 : sum;
}
static inline long get_nr_inodes_unused(void)
{
int i;
long sum = 0;
for_each_possible_cpu(i)
sum += per_cpu(nr_unused, i);
return sum < 0 ? 0 : sum;
}
long get_nr_dirty_inodes(void)
{
/* not actually dirty inodes, but a wild approximation */
long nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
return nr_dirty > 0 ? nr_dirty : 0;
}
/*
* Handle nr_inode sysctl
*/
#ifdef CONFIG_SYSCTL
/*
* Statistics gathering..
*/
static struct inodes_stat_t inodes_stat;
static int proc_nr_inodes(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
inodes_stat.nr_inodes = get_nr_inodes();
inodes_stat.nr_unused = get_nr_inodes_unused();
return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
}
static struct ctl_table inodes_sysctls[] = {
{
.procname = "inode-nr",
.data = &inodes_stat,
.maxlen = 2*sizeof(long),
.mode = 0444,
.proc_handler = proc_nr_inodes,
},
{
.procname = "inode-state",
.data = &inodes_stat,
.maxlen = 7*sizeof(long),
.mode = 0444,
.proc_handler = proc_nr_inodes,
},
{ }
};
static int __init init_fs_inode_sysctls(void)
{
register_sysctl_init("fs", inodes_sysctls);
return 0;
}
early_initcall(init_fs_inode_sysctls);
#endif
static int no_open(struct inode *inode, struct file *file)
{
return -ENXIO;
}
/**
* inode_init_always - perform inode structure initialisation
* @sb: superblock inode belongs to
* @inode: inode to initialise
*
* These are initializations that need to be done on every inode
* allocation as the fields are not initialised by slab allocation.
*/
int inode_init_always(struct super_block *sb, struct inode *inode)
{
static const struct inode_operations empty_iops;
static const struct file_operations no_open_fops = {.open = no_open};
struct address_space *const mapping = &inode->i_data;
inode->i_sb = sb;
inode->i_blkbits = sb->s_blocksize_bits;
inode->i_flags = 0;
atomic64_set(&inode->i_sequence, 0);
atomic_set(&inode->i_count, 1);
inode->i_op = &empty_iops;
inode->i_fop = &no_open_fops;
inode->i_ino = 0;
inode->__i_nlink = 1;
inode->i_opflags = 0;
if (sb->s_xattr)
inode->i_opflags |= IOP_XATTR;
i_uid_write(inode, 0);
i_gid_write(inode, 0);
atomic_set(&inode->i_writecount, 0);
inode->i_size = 0;
inode->i_write_hint = WRITE_LIFE_NOT_SET;
inode->i_blocks = 0;
inode->i_bytes = 0;
inode->i_generation = 0;
inode->i_pipe = NULL;
inode->i_cdev = NULL;
inode->i_link = NULL;
inode->i_dir_seq = 0;
inode->i_rdev = 0;
inode->dirtied_when = 0;
#ifdef CONFIG_CGROUP_WRITEBACK
inode->i_wb_frn_winner = 0;
inode->i_wb_frn_avg_time = 0;
inode->i_wb_frn_history = 0;
#endif
spin_lock_init(&inode->i_lock);
lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
init_rwsem(&inode->i_rwsem);
lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key);
atomic_set(&inode->i_dio_count, 0);
mapping->a_ops = &empty_aops;
mapping->host = inode;
mapping->flags = 0;
mapping->wb_err = 0;
atomic_set(&mapping->i_mmap_writable, 0);
#ifdef CONFIG_READ_ONLY_THP_FOR_FS
atomic_set(&mapping->nr_thps, 0);
#endif
mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
mapping->private_data = NULL;
mapping->writeback_index = 0;
init_rwsem(&mapping->invalidate_lock);
lockdep_set_class_and_name(&mapping->invalidate_lock,
&sb->s_type->invalidate_lock_key,
"mapping.invalidate_lock");
inode->i_private = NULL;
inode->i_mapping = mapping;
INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
#ifdef CONFIG_FS_POSIX_ACL
inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
#endif
#ifdef CONFIG_FSNOTIFY
inode->i_fsnotify_mask = 0;
#endif
inode->i_flctx = NULL;
if (unlikely(security_inode_alloc(inode)))
return -ENOMEM;
this_cpu_inc(nr_inodes);
return 0;
}
EXPORT_SYMBOL(inode_init_always);
void free_inode_nonrcu(struct inode *inode)
{
kmem_cache_free(inode_cachep, inode);
}
EXPORT_SYMBOL(free_inode_nonrcu);
static void i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
if (inode->free_inode)
inode->free_inode(inode);
else
free_inode_nonrcu(inode);
}
static struct inode *alloc_inode(struct super_block *sb)
{
const struct super_operations *ops = sb->s_op;
struct inode *inode;
if (ops->alloc_inode)
inode = ops->alloc_inode(sb);
else
inode = alloc_inode_sb(sb, inode_cachep, GFP_KERNEL);
if (!inode)
return NULL;
if (unlikely(inode_init_always(sb, inode))) {
if (ops->destroy_inode) {
ops->destroy_inode(inode);
if (!ops->free_inode)
return NULL;
}
inode->free_inode = ops->free_inode;
i_callback(&inode->i_rcu);
return NULL;
}
return inode;
}
void __destroy_inode(struct inode *inode)
{
BUG_ON(inode_has_buffers(inode));
inode_detach_wb(inode);
security_inode_free(inode);
fsnotify_inode_delete(inode);
locks_free_lock_context(inode);
if (!inode->i_nlink) {
WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
atomic_long_dec(&inode->i_sb->s_remove_count);
}
#ifdef CONFIG_FS_POSIX_ACL
if (inode->i_acl && !is_uncached_acl(inode->i_acl))
posix_acl_release(inode->i_acl);
if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl))
posix_acl_release(inode->i_default_acl);
#endif
this_cpu_dec(nr_inodes);
}
EXPORT_SYMBOL(__destroy_inode);
static void destroy_inode(struct inode *inode)
{
const struct super_operations *ops = inode->i_sb->s_op;
BUG_ON(!list_empty(&inode->i_lru));
__destroy_inode(inode);
if (ops->destroy_inode) {
ops->destroy_inode(inode);
if (!ops->free_inode)
return;
}
inode->free_inode = ops->free_inode;
call_rcu(&inode->i_rcu, i_callback);
}
/**
* drop_nlink - directly drop an inode's link count
* @inode: inode
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink. In cases
* where we are attempting to track writes to the
* filesystem, a decrement to zero means an imminent
* write when the file is truncated and actually unlinked
* on the filesystem.
*/
void drop_nlink(struct inode *inode)
{
WARN_ON(inode->i_nlink == 0);
inode->__i_nlink--;
if (!inode->i_nlink)
atomic_long_inc(&inode->i_sb->s_remove_count);
}
EXPORT_SYMBOL(drop_nlink);
/**
* clear_nlink - directly zero an inode's link count
* @inode: inode
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink. See
* drop_nlink() for why we care about i_nlink hitting zero.
*/
void clear_nlink(struct inode *inode)
{
if (inode->i_nlink) {
inode->__i_nlink = 0;
atomic_long_inc(&inode->i_sb->s_remove_count);
}
}
EXPORT_SYMBOL(clear_nlink);
/**
* set_nlink - directly set an inode's link count
* @inode: inode
* @nlink: new nlink (should be non-zero)
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink.
*/
void set_nlink(struct inode *inode, unsigned int nlink)
{
if (!nlink) {
clear_nlink(inode);
} else {
/* Yes, some filesystems do change nlink from zero to one */
if (inode->i_nlink == 0)
atomic_long_dec(&inode->i_sb->s_remove_count);
inode->__i_nlink = nlink;
}
}
EXPORT_SYMBOL(set_nlink);
/**
* inc_nlink - directly increment an inode's link count
* @inode: inode
*
* This is a low-level filesystem helper to replace any
* direct filesystem manipulation of i_nlink. Currently,
* it is only here for parity with dec_nlink().
*/
void inc_nlink(struct inode *inode)
{
if (unlikely(inode->i_nlink == 0)) {
WARN_ON(!(inode->i_state & I_LINKABLE));
atomic_long_dec(&inode->i_sb->s_remove_count);
}
inode->__i_nlink++;
}
EXPORT_SYMBOL(inc_nlink);
static void __address_space_init_once(struct address_space *mapping)
{
xa_init_flags(&mapping->i_pages, XA_FLAGS_LOCK_IRQ | XA_FLAGS_ACCOUNT);
init_rwsem(&mapping->i_mmap_rwsem);
INIT_LIST_HEAD(&mapping->private_list);
spin_lock_init(&mapping->private_lock);
mapping->i_mmap = RB_ROOT_CACHED;
}
void address_space_init_once(struct address_space *mapping)
{
memset(mapping, 0, sizeof(*mapping));
__address_space_init_once(mapping);
}
EXPORT_SYMBOL(address_space_init_once);
/*
* These are initializations that only need to be done
* once, because the fields are idempotent across use
* of the inode, so let the slab aware of that.
*/
void inode_init_once(struct inode *inode)
{
memset(inode, 0, sizeof(*inode));
INIT_HLIST_NODE(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_devices);
INIT_LIST_HEAD(&inode->i_io_list);
INIT_LIST_HEAD(&inode->i_wb_list);
INIT_LIST_HEAD(&inode->i_lru);
INIT_LIST_HEAD(&inode->i_sb_list);
__address_space_init_once(&inode->i_data);
i_size_ordered_init(inode);
}
EXPORT_SYMBOL(inode_init_once);
static void init_once(void *foo)
{
struct inode *inode = (struct inode *) foo;
inode_init_once(inode);
}
/*
* inode->i_lock must be held
*/
void __iget(struct inode *inode)
{
atomic_inc(&inode->i_count);
}
/*
* get additional reference to inode; caller must already hold one.
*/
void ihold(struct inode *inode)
{
WARN_ON(atomic_inc_return(&inode->i_count) < 2);
}
EXPORT_SYMBOL(ihold);
static void __inode_add_lru(struct inode *inode, bool rotate)
{
if (inode->i_state & (I_DIRTY_ALL | I_SYNC | I_FREEING | I_WILL_FREE))
return;
if (atomic_read(&inode->i_count))
return;
if (!(inode->i_sb->s_flags & SB_ACTIVE))
return;
if (!mapping_shrinkable(&inode->i_data))
return;
if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
this_cpu_inc(nr_unused);
else if (rotate)
inode->i_state |= I_REFERENCED;
}
/*
* Add inode to LRU if needed (inode is unused and clean).
*
* Needs inode->i_lock held.
*/
void inode_add_lru(struct inode *inode)
{
__inode_add_lru(inode, false);
}
static void inode_lru_list_del(struct inode *inode)
{
if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
this_cpu_dec(nr_unused);
}
/**
* inode_sb_list_add - add inode to the superblock list of inodes
* @inode: inode to add
*/
void inode_sb_list_add(struct inode *inode)
{
spin_lock(&inode->i_sb->s_inode_list_lock);
list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
spin_unlock(&inode->i_sb->s_inode_list_lock);
}
EXPORT_SYMBOL_GPL(inode_sb_list_add);
static inline void inode_sb_list_del(struct inode *inode)
{
if (!list_empty(&inode->i_sb_list)) {
spin_lock(&inode->i_sb->s_inode_list_lock);
list_del_init(&inode->i_sb_list);
spin_unlock(&inode->i_sb->s_inode_list_lock);
}
}
static unsigned long hash(struct super_block *sb, unsigned long hashval)
{
unsigned long tmp;
tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
L1_CACHE_BYTES;
tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
return tmp & i_hash_mask;
}
/**
* __insert_inode_hash - hash an inode
* @inode: unhashed inode
* @hashval: unsigned long value used to locate this object in the
* inode_hashtable.
*
* Add an inode to the inode hash for this superblock.
*/
void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
spin_lock(&inode_hash_lock);
spin_lock(&inode->i_lock);
hlist_add_head_rcu(&inode->i_hash, b);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);
/**
* __remove_inode_hash - remove an inode from the hash
* @inode: inode to unhash
*
* Remove an inode from the superblock.
*/
void __remove_inode_hash(struct inode *inode)
{
spin_lock(&inode_hash_lock);
spin_lock(&inode->i_lock);
hlist_del_init_rcu(&inode->i_hash);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__remove_inode_hash);
void dump_mapping(const struct address_space *mapping)
{
struct inode *host;
const struct address_space_operations *a_ops;
struct hlist_node *dentry_first;
struct dentry *dentry_ptr;
struct dentry dentry;
unsigned long ino;
/*
* If mapping is an invalid pointer, we don't want to crash
* accessing it, so probe everything depending on it carefully.
*/
if (get_kernel_nofault(host, &mapping->host) ||
get_kernel_nofault(a_ops, &mapping->a_ops)) {
pr_warn("invalid mapping:%px\n", mapping);
return;
}
if (!host) {
pr_warn("aops:%ps\n", a_ops);
return;
}
if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
get_kernel_nofault(ino, &host->i_ino)) {
pr_warn("aops:%ps invalid inode:%px\n", a_ops, host);
return;
}
if (!dentry_first) {
pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
return;
}
dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
if (get_kernel_nofault(dentry, dentry_ptr)) {
pr_warn("aops:%ps ino:%lx invalid dentry:%px\n",
a_ops, ino, dentry_ptr);
return;
}
/*
* if dentry is corrupted, the %pd handler may still crash,
* but it's unlikely that we reach here with a corrupt mapping
*/
pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry);
}
void clear_inode(struct inode *inode)
{
/*
* We have to cycle the i_pages lock here because reclaim can be in the
* process of removing the last page (in __filemap_remove_folio())
* and we must not free the mapping under it.
*/
xa_lock_irq(&inode->i_data.i_pages);
BUG_ON(inode->i_data.nrpages);
/*
* Almost always, mapping_empty(&inode->i_data) here; but there are
* two known and long-standing ways in which nodes may get left behind
* (when deep radix-tree node allocation failed partway; or when THP
* collapse_file() failed). Until those two known cases are cleaned up,
* or a cleanup function is called here, do not BUG_ON(!mapping_empty),
* nor even WARN_ON(!mapping_empty).
*/
xa_unlock_irq(&inode->i_data.i_pages);
BUG_ON(!list_empty(&inode->i_data.private_list));
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(inode->i_state & I_CLEAR);
BUG_ON(!list_empty(&inode->i_wb_list));
/* don't need i_lock here, no concurrent mods to i_state */
inode->i_state = I_FREEING | I_CLEAR;
}
EXPORT_SYMBOL(clear_inode);
/*
* Free the inode passed in, removing it from the lists it is still connected
* to. We remove any pages still attached to the inode and wait for any IO that
* is still in progress before finally destroying the inode.
*
* An inode must already be marked I_FREEING so that we avoid the inode being
* moved back onto lists if we race with other code that manipulates the lists
* (e.g. writeback_single_inode). The caller is responsible for setting this.
*
* An inode must already be removed from the LRU list before being evicted from
* the cache. This should occur atomically with setting the I_FREEING state
* flag, so no inodes here should ever be on the LRU when being evicted.
*/
static void evict(struct inode *inode)
{
const struct super_operations *op = inode->i_sb->s_op;
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(!list_empty(&inode->i_lru));
if (!list_empty(&inode->i_io_list))
inode_io_list_del(inode);
inode_sb_list_del(inode);
/*
* Wait for flusher thread to be done with the inode so that filesystem
* does not start destroying it while writeback is still running. Since
* the inode has I_FREEING set, flusher thread won't start new work on
* the inode. We just have to wait for running writeback to finish.
*/
inode_wait_for_writeback(inode);
if (op->evict_inode) {
op->evict_inode(inode);
} else {
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
}
if (S_ISCHR(inode->i_mode) && inode->i_cdev)
cd_forget(inode);
remove_inode_hash(inode);
spin_lock(&inode->i_lock);
wake_up_bit(&inode->i_state, __I_NEW);
BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
spin_unlock(&inode->i_lock);
destroy_inode(inode);
}
/*
* dispose_list - dispose of the contents of a local list
* @head: the head of the list to free
*
* Dispose-list gets a local list with local inodes in it, so it doesn't
* need to worry about list corruption and SMP locks.
*/
static void dispose_list(struct list_head *head)
{
while (!list_empty(head)) {
struct inode *inode;
inode = list_first_entry(head, struct inode, i_lru);
list_del_init(&inode->i_lru);
evict(inode);
cond_resched();
}
}
/**
* evict_inodes - evict all evictable inodes for a superblock
* @sb: superblock to operate on
*
* Make sure that no inodes with zero refcount are retained. This is
* called by superblock shutdown after having SB_ACTIVE flag removed,
* so any inode reaching zero refcount during or after that call will
* be immediately evicted.
*/
void evict_inodes(struct super_block *sb)
{
struct inode *inode, *next;
LIST_HEAD(dispose);
again:
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
if (atomic_read(&inode->i_count))
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
spin_unlock(&inode->i_lock);
continue;
}
inode->i_state |= I_FREEING;
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
list_add(&inode->i_lru, &dispose);
/*
* We can have a ton of inodes to evict at unmount time given
* enough memory, check to see if we need to go to sleep for a
* bit so we don't livelock.
*/
if (need_resched()) {
spin_unlock(&sb->s_inode_list_lock);
cond_resched();
dispose_list(&dispose);
goto again;
}
}
spin_unlock(&sb->s_inode_list_lock);
dispose_list(&dispose);
}
EXPORT_SYMBOL_GPL(evict_inodes);
/**
* invalidate_inodes - attempt to free all inodes on a superblock
* @sb: superblock to operate on
*
* Attempts to free all inodes (including dirty inodes) for a given superblock.
*/
void invalidate_inodes(struct super_block *sb)
{
struct inode *inode, *next;
LIST_HEAD(dispose);
again:
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
spin_unlock(&inode->i_lock);
continue;
}
if (atomic_read(&inode->i_count)) {
spin_unlock(&inode->i_lock);
continue;
}
inode->i_state |= I_FREEING;
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
list_add(&inode->i_lru, &dispose);
if (need_resched()) {
spin_unlock(&sb->s_inode_list_lock);
cond_resched();
dispose_list(&dispose);
goto again;
}
}
spin_unlock(&sb->s_inode_list_lock);
dispose_list(&dispose);
}
/*
* Isolate the inode from the LRU in preparation for freeing it.
*
* If the inode has the I_REFERENCED flag set, then it means that it has been
* used recently - the flag is set in iput_final(). When we encounter such an
* inode, clear the flag and move it to the back of the LRU so it gets another
* pass through the LRU before it gets reclaimed. This is necessary because of
* the fact we are doing lazy LRU updates to minimise lock contention so the
* LRU does not have strict ordering. Hence we don't want to reclaim inodes
* with this flag set because they are the inodes that are out of order.
*/
static enum lru_status inode_lru_isolate(struct list_head *item,
struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
{
struct list_head *freeable = arg;
struct inode *inode = container_of(item, struct inode, i_lru);
/*
* We are inverting the lru lock/inode->i_lock here, so use a
* trylock. If we fail to get the lock, just skip it.
*/
if (!spin_trylock(&inode->i_lock))
return LRU_SKIP;
/*
* Inodes can get referenced, redirtied, or repopulated while
* they're already on the LRU, and this can make them
* unreclaimable for a while. Remove them lazily here; iput,
* sync, or the last page cache deletion will requeue them.
*/
if (atomic_read(&inode->i_count) ||
(inode->i_state & ~I_REFERENCED) ||
!mapping_shrinkable(&inode->i_data)) {
list_lru_isolate(lru, &inode->i_lru);
spin_unlock(&inode->i_lock);
this_cpu_dec(nr_unused);
return LRU_REMOVED;
}
/* Recently referenced inodes get one more pass */
if (inode->i_state & I_REFERENCED) {
inode->i_state &= ~I_REFERENCED;
spin_unlock(&inode->i_lock);
return LRU_ROTATE;
}
/*
* On highmem systems, mapping_shrinkable() permits dropping
* page cache in order to free up struct inodes: lowmem might
* be under pressure before the cache inside the highmem zone.
*/
if (inode_has_buffers(inode) || !mapping_empty(&inode->i_data)) {
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(lru_lock);
if (remove_inode_buffers(inode)) {
unsigned long reap;
reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
if (current_is_kswapd())
__count_vm_events(KSWAPD_INODESTEAL, reap);
else
__count_vm_events(PGINODESTEAL, reap);
mm_account_reclaimed_pages(reap);
}
iput(inode);
spin_lock(lru_lock);
return LRU_RETRY;
}
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
list_lru_isolate_move(lru, &inode->i_lru, freeable);
spin_unlock(&inode->i_lock);
this_cpu_dec(nr_unused);
return LRU_REMOVED;
}
/*
* Walk the superblock inode LRU for freeable inodes and attempt to free them.
* This is called from the superblock shrinker function with a number of inodes
* to trim from the LRU. Inodes to be freed are moved to a temporary list and
* then are freed outside inode_lock by dispose_list().
*/
long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
{
LIST_HEAD(freeable);
long freed;
freed = list_lru_shrink_walk(&sb->s_inode_lru, sc,
inode_lru_isolate, &freeable);
dispose_list(&freeable);
return freed;
}
static void __wait_on_freeing_inode(struct inode *inode);
/*
* Called with the inode lock held.
*/
static struct inode *find_inode(struct super_block *sb,
struct hlist_head *head,
int (*test)(struct inode *, void *),
void *data)
{
struct inode *inode = NULL;
repeat:
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_sb != sb)
continue;
if (!test(inode, data))
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
if (unlikely(inode->i_state & I_CREATING)) {
spin_unlock(&inode->i_lock);
return ERR_PTR(-ESTALE);
}
__iget(inode);
spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
}
/*
* find_inode_fast is the fast path version of find_inode, see the comment at
* iget_locked for details.
*/
static struct inode *find_inode_fast(struct super_block *sb,
struct hlist_head *head, unsigned long ino)
{
struct inode *inode = NULL;
repeat:
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_ino != ino)
continue;
if (inode->i_sb != sb)
continue;
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
__wait_on_freeing_inode(inode);
goto repeat;
}
if (unlikely(inode->i_state & I_CREATING)) {
spin_unlock(&inode->i_lock);
return ERR_PTR(-ESTALE);
}
__iget(inode);
spin_unlock(&inode->i_lock);
return inode;
}
return NULL;
}
/*
* Each cpu owns a range of LAST_INO_BATCH numbers.
* 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
* to renew the exhausted range.
*
* This does not significantly increase overflow rate because every CPU can
* consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
* NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
* 2^32 range, and is a worst-case. Even a 50% wastage would only increase
* overflow rate by 2x, which does not seem too significant.
*
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
* error if st_ino won't fit in target struct field. Use 32bit counter
* here to attempt to avoid that.
*/
#define LAST_INO_BATCH 1024
static DEFINE_PER_CPU(unsigned int, last_ino);
unsigned int get_next_ino(void)
{
unsigned int *p = &get_cpu_var(last_ino);
unsigned int res = *p;
#ifdef CONFIG_SMP
if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
static atomic_t shared_last_ino;
int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
res = next - LAST_INO_BATCH;
}
#endif
res++;
/* get_next_ino should not provide a 0 inode number */
if (unlikely(!res))
res++;
*p = res;
put_cpu_var(last_ino);
return res;
}
EXPORT_SYMBOL(get_next_ino);
/**
* new_inode_pseudo - obtain an inode
* @sb: superblock
*
* Allocates a new inode for given superblock.
* Inode wont be chained in superblock s_inodes list
* This means :
* - fs can't be unmount
* - quotas, fsnotify, writeback can't work
*/
struct inode *new_inode_pseudo(struct super_block *sb)
{
struct inode *inode = alloc_inode(sb);
if (inode) {
spin_lock(&inode->i_lock);
inode->i_state = 0;
spin_unlock(&inode->i_lock);
}
return inode;
}
/**
* new_inode - obtain an inode
* @sb: superblock
*
* Allocates a new inode for given superblock. The default gfp_mask
* for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
* If HIGHMEM pages are unsuitable or it is known that pages allocated
* for the page cache are not reclaimable or migratable,
* mapping_set_gfp_mask() must be called with suitable flags on the
* newly created inode's mapping
*
*/
struct inode *new_inode(struct super_block *sb)
{
struct inode *inode;
inode = new_inode_pseudo(sb);
if (inode)
inode_sb_list_add(inode);
return inode;
}
EXPORT_SYMBOL(new_inode);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void lockdep_annotate_inode_mutex_key(struct inode *inode)
{
if (S_ISDIR(inode->i_mode)) {
struct file_system_type *type = inode->i_sb->s_type;
/* Set new key only if filesystem hasn't already changed it */
if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) {
/*
* ensure nobody is actually holding i_mutex
*/
// mutex_destroy(&inode->i_mutex);
init_rwsem(&inode->i_rwsem);
lockdep_set_class(&inode->i_rwsem,
&type->i_mutex_dir_key);
}
}
}
EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
#endif
/**
* unlock_new_inode - clear the I_NEW state and wake up any waiters
* @inode: new inode to unlock
*
* Called when the inode is fully initialised to clear the new state of the
* inode and wake up anyone waiting for the inode to finish initialisation.
*/
void unlock_new_inode(struct inode *inode)
{
lockdep_annotate_inode_mutex_key(inode);
spin_lock(&inode->i_lock);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW & ~I_CREATING;
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(unlock_new_inode);
void discard_new_inode(struct inode *inode)
{
lockdep_annotate_inode_mutex_key(inode);
spin_lock(&inode->i_lock);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW;
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
spin_unlock(&inode->i_lock);
iput(inode);
}
EXPORT_SYMBOL(discard_new_inode);
/**
* lock_two_inodes - lock two inodes (may be regular files but also dirs)
*
* Lock any non-NULL argument. The caller must make sure that if he is passing
* in two directories, one is not ancestor of the other. Zero, one or two
* objects may be locked by this function.
*
* @inode1: first inode to lock
* @inode2: second inode to lock
* @subclass1: inode lock subclass for the first lock obtained
* @subclass2: inode lock subclass for the second lock obtained
*/
void lock_two_inodes(struct inode *inode1, struct inode *inode2,
unsigned subclass1, unsigned subclass2)
{
if (!inode1 || !inode2) {
/*
* Make sure @subclass1 will be used for the acquired lock.
* This is not strictly necessary (no current caller cares) but
* let's keep things consistent.
*/
if (!inode1)
swap(inode1, inode2);
goto lock;
}
/*
* If one object is directory and the other is not, we must make sure
* to lock directory first as the other object may be its child.
*/
if (S_ISDIR(inode2->i_mode) == S_ISDIR(inode1->i_mode)) {
if (inode1 > inode2)
swap(inode1, inode2);
} else if (!S_ISDIR(inode1->i_mode))
swap(inode1, inode2);
lock:
if (inode1)
inode_lock_nested(inode1, subclass1);
if (inode2 && inode2 != inode1)
inode_lock_nested(inode2, subclass2);
}
/**
* lock_two_nondirectories - take two i_mutexes on non-directory objects
*
* Lock any non-NULL argument. Passed objects must not be directories.
* Zero, one or two objects may be locked by this function.
*
* @inode1: first inode to lock
* @inode2: second inode to lock
*/
void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
if (inode1)
WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
if (inode2)
WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
lock_two_inodes(inode1, inode2, I_MUTEX_NORMAL, I_MUTEX_NONDIR2);
}
EXPORT_SYMBOL(lock_two_nondirectories);
/**
* unlock_two_nondirectories - release locks from lock_two_nondirectories()
* @inode1: first inode to unlock
* @inode2: second inode to unlock
*/
void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
if (inode1) {
WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
inode_unlock(inode1);
}
if (inode2 && inode2 != inode1) {
WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
inode_unlock(inode2);
}
}
EXPORT_SYMBOL(unlock_two_nondirectories);
/**
* inode_insert5 - obtain an inode from a mounted file system
* @inode: pre-allocated inode to use for insert to cache
* @hashval: hash value (usually inode number) to get
* @test: callback used for comparisons between inodes
* @set: callback used to initialize a new struct inode
* @data: opaque data pointer to pass to @test and @set
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if present it is return it with an increased reference count. This is
* a variant of iget5_locked() for callers that don't want to fail on memory
* allocation of inode.
*
* If the inode is not in cache, insert the pre-allocated inode to cache and
* return it locked, hashed, and with the I_NEW flag set. The file system gets
* to fill it in before unlocking it via unlock_new_inode().
*
* Note both @test and @set are called with the inode_hash_lock held, so can't
* sleep.
*/
struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
struct inode *old;
again:
spin_lock(&inode_hash_lock);
old = find_inode(inode->i_sb, head, test, data);
if (unlikely(old)) {
/*
* Uhhuh, somebody else created the same inode under us.
* Use the old inode instead of the preallocated one.
*/
spin_unlock(&inode_hash_lock);
if (IS_ERR(old))
return NULL;
wait_on_inode(old);
if (unlikely(inode_unhashed(old))) {
iput(old);
goto again;
}
return old;
}
if (set && unlikely(set(inode, data))) {
inode = NULL;
goto unlock;
}
/*
* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
*/
spin_lock(&inode->i_lock);
inode->i_state |= I_NEW;
hlist_add_head_rcu(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
/*
* Add inode to the sb list if it's not already. It has I_NEW at this
* point, so it should be safe to test i_sb_list locklessly.
*/
if (list_empty(&inode->i_sb_list))
inode_sb_list_add(inode);
unlock:
spin_unlock(&inode_hash_lock);
return inode;
}
EXPORT_SYMBOL(inode_insert5);
/**
* iget5_locked - obtain an inode from a mounted file system
* @sb: super block of file system
* @hashval: hash value (usually inode number) to get
* @test: callback used for comparisons between inodes
* @set: callback used to initialize a new struct inode
* @data: opaque data pointer to pass to @test and @set
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if present it is return it with an increased reference count. This is
* a generalized version of iget_locked() for file systems where the inode
* number is not sufficient for unique identification of an inode.
*
* If the inode is not in cache, allocate a new inode and return it locked,
* hashed, and with the I_NEW flag set. The file system gets to fill it in
* before unlocking it via unlock_new_inode().
*
* Note both @test and @set are called with the inode_hash_lock held, so can't
* sleep.
*/
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
struct inode *inode = ilookup5(sb, hashval, test, data);
if (!inode) {
struct inode *new = alloc_inode(sb);
if (new) {
new->i_state = 0;
inode = inode_insert5(new, hashval, test, set, data);
if (unlikely(inode != new))
destroy_inode(new);
}
}
return inode;
}
EXPORT_SYMBOL(iget5_locked);
/**
* iget_locked - obtain an inode from a mounted file system
* @sb: super block of file system
* @ino: inode number to get
*
* Search for the inode specified by @ino in the inode cache and if present
* return it with an increased reference count. This is for file systems
* where the inode number is sufficient for unique identification of an inode.
*
* If the inode is not in cache, allocate a new inode and return it locked,
* hashed, and with the I_NEW flag set. The file system gets to fill it in
* before unlocking it via unlock_new_inode().
*/
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
again:
spin_lock(&inode_hash_lock);
inode = find_inode_fast(sb, head, ino);
spin_unlock(&inode_hash_lock);
if (inode) {
if (IS_ERR(inode))
return NULL;
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
return inode;
}
inode = alloc_inode(sb);
if (inode) {
struct inode *old;
spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode_fast(sb, head, ino);
if (!old) {
inode->i_ino = ino;
spin_lock(&inode->i_lock);
inode->i_state = I_NEW;
hlist_add_head_rcu(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
inode_sb_list_add(inode);
spin_unlock(&inode_hash_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
*/
return inode;
}
/*
* Uhhuh, somebody else created the same inode under
* us. Use the old inode instead of the one we just
* allocated.
*/
spin_unlock(&inode_hash_lock);
destroy_inode(inode);
if (IS_ERR(old))
return NULL;
inode = old;
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
}
return inode;
}
EXPORT_SYMBOL(iget_locked);
/*
* search the inode cache for a matching inode number.
* If we find one, then the inode number we are trying to
* allocate is not unique and so we should not use it.
*
* Returns 1 if the inode number is unique, 0 if it is not.
*/
static int test_inode_iunique(struct super_block *sb, unsigned long ino)
{
struct hlist_head *b = inode_hashtable + hash(sb, ino);
struct inode *inode;
hlist_for_each_entry_rcu(inode, b, i_hash) {
if (inode->i_ino == ino && inode->i_sb == sb)
return 0;
}
return 1;
}
/**
* iunique - get a unique inode number
* @sb: superblock
* @max_reserved: highest reserved inode number
*
* Obtain an inode number that is unique on the system for a given
* superblock. This is used by file systems that have no natural
* permanent inode numbering system. An inode number is returned that
* is higher than the reserved limit but unique.
*
* BUGS:
* With a large number of inodes live on the file system this function
* currently becomes quite slow.
*/
ino_t iunique(struct super_block *sb, ino_t max_reserved)
{
/*
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
* error if st_ino won't fit in target struct field. Use 32bit counter
* here to attempt to avoid that.
*/
static DEFINE_SPINLOCK(iunique_lock);
static unsigned int counter;
ino_t res;
rcu_read_lock();
spin_lock(&iunique_lock);
do {
if (counter <= max_reserved)
counter = max_reserved + 1;
res = counter++;
} while (!test_inode_iunique(sb, res));
spin_unlock(&iunique_lock);
rcu_read_unlock();
return res;
}
EXPORT_SYMBOL(iunique);
struct inode *igrab(struct inode *inode)
{
spin_lock(&inode->i_lock);
if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
__iget(inode);
spin_unlock(&inode->i_lock);
} else {
spin_unlock(&inode->i_lock);
/*
* Handle the case where s_op->clear_inode is not been
* called yet, and somebody is calling igrab
* while the inode is getting freed.
*/
inode = NULL;
}
return inode;
}
EXPORT_SYMBOL(igrab);
/**
* ilookup5_nowait - search for an inode in the inode cache
* @sb: super block of file system to search
* @hashval: hash value (usually inode number) to search for
* @test: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @test
*
* Search for the inode specified by @hashval and @data in the inode cache.
* If the inode is in the cache, the inode is returned with an incremented
* reference count.
*
* Note: I_NEW is not waited upon so you have to be very careful what you do
* with the returned inode. You probably should be using ilookup5() instead.
*
* Note2: @test is called with the inode_hash_lock held, so can't sleep.
*/
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
struct inode *inode;
spin_lock(&inode_hash_lock);
inode = find_inode(sb, head, test, data);
spin_unlock(&inode_hash_lock);
return IS_ERR(inode) ? NULL : inode;
}
EXPORT_SYMBOL(ilookup5_nowait);
/**
* ilookup5 - search for an inode in the inode cache
* @sb: super block of file system to search
* @hashval: hash value (usually inode number) to search for
* @test: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @test
*
* Search for the inode specified by @hashval and @data in the inode cache,
* and if the inode is in the cache, return the inode with an incremented
* reference count. Waits on I_NEW before returning the inode.
* returned with an incremented reference count.
*
* This is a generalized version of ilookup() for file systems where the
* inode number is not sufficient for unique identification of an inode.
*
* Note: @test is called with the inode_hash_lock held, so can't sleep.
*/
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct inode *inode;
again:
inode = ilookup5_nowait(sb, hashval, test, data);
if (inode) {
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
}
return inode;
}
EXPORT_SYMBOL(ilookup5);
/**
* ilookup - search for an inode in the inode cache
* @sb: super block of file system to search
* @ino: inode number to search for
*
* Search for the inode @ino in the inode cache, and if the inode is in the
* cache, the inode is returned with an incremented reference count.
*/
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
again:
spin_lock(&inode_hash_lock);
inode = find_inode_fast(sb, head, ino);
spin_unlock(&inode_hash_lock);
if (inode) {
if (IS_ERR(inode))
return NULL;
wait_on_inode(inode);
if (unlikely(inode_unhashed(inode))) {
iput(inode);
goto again;
}
}
return inode;
}
EXPORT_SYMBOL(ilookup);
/**
* find_inode_nowait - find an inode in the inode cache
* @sb: super block of file system to search
* @hashval: hash value (usually inode number) to search for
* @match: callback used for comparisons between inodes
* @data: opaque data pointer to pass to @match
*
* Search for the inode specified by @hashval and @data in the inode
* cache, where the helper function @match will return 0 if the inode
* does not match, 1 if the inode does match, and -1 if the search
* should be stopped. The @match function must be responsible for
* taking the i_lock spin_lock and checking i_state for an inode being
* freed or being initialized, and incrementing the reference count
* before returning 1. It also must not sleep, since it is called with
* the inode_hash_lock spinlock held.
*
* This is a even more generalized version of ilookup5() when the
* function must never block --- find_inode() can block in
* __wait_on_freeing_inode() --- or when the caller can not increment
* the reference count because the resulting iput() might cause an
* inode eviction. The tradeoff is that the @match funtion must be
* very carefully implemented.
*/
struct inode *find_inode_nowait(struct super_block *sb,
unsigned long hashval,
int (*match)(struct inode *, unsigned long,
void *),
void *data)
{
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
struct inode *inode, *ret_inode = NULL;
int mval;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(inode, head, i_hash) {
if (inode->i_sb != sb)
continue;
mval = match(inode, hashval, data);
if (mval == 0)
continue;
if (mval == 1)
ret_inode = inode;
goto out;
}
out:
spin_unlock(&inode_hash_lock);
return ret_inode;
}
EXPORT_SYMBOL(find_inode_nowait);
/**
* find_inode_rcu - find an inode in the inode cache
* @sb: Super block of file system to search
* @hashval: Key to hash
* @test: Function to test match on an inode
* @data: Data for test function
*
* Search for the inode specified by @hashval and @data in the inode cache,
* where the helper function @test will return 0 if the inode does not match
* and 1 if it does. The @test function must be responsible for taking the
* i_lock spin_lock and checking i_state for an inode being freed or being
* initialized.
*
* If successful, this will return the inode for which the @test function
* returned 1 and NULL otherwise.
*
* The @test function is not permitted to take a ref on any inode presented.
* It is also not permitted to sleep.
*
* The caller must hold the RCU read lock.
*/
struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
struct inode *inode;
RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
"suspicious find_inode_rcu() usage");
hlist_for_each_entry_rcu(inode, head, i_hash) {
if (inode->i_sb == sb &&
!(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)) &&
test(inode, data))
return inode;
}
return NULL;
}
EXPORT_SYMBOL(find_inode_rcu);
/**
* find_inode_by_ino_rcu - Find an inode in the inode cache
* @sb: Super block of file system to search
* @ino: The inode number to match
*
* Search for the inode specified by @hashval and @data in the inode cache,
* where the helper function @test will return 0 if the inode does not match
* and 1 if it does. The @test function must be responsible for taking the
* i_lock spin_lock and checking i_state for an inode being freed or being
* initialized.
*
* If successful, this will return the inode for which the @test function
* returned 1 and NULL otherwise.
*
* The @test function is not permitted to take a ref on any inode presented.
* It is also not permitted to sleep.
*
* The caller must hold the RCU read lock.
*/
struct inode *find_inode_by_ino_rcu(struct super_block *sb,
unsigned long ino)
{
struct hlist_head *head = inode_hashtable + hash(sb, ino);
struct inode *inode;
RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
"suspicious find_inode_by_ino_rcu() usage");
hlist_for_each_entry_rcu(inode, head, i_hash) {
if (inode->i_ino == ino &&
inode->i_sb == sb &&
!(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)))
return inode;
}
return NULL;
}
EXPORT_SYMBOL(find_inode_by_ino_rcu);
int insert_inode_locked(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
struct hlist_head *head = inode_hashtable + hash(sb, ino);
while (1) {
struct inode *old = NULL;
spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, head, i_hash) {
if (old->i_ino != ino)
continue;
if (old->i_sb != sb)
continue;
spin_lock(&old->i_lock);
if (old->i_state & (I_FREEING|I_WILL_FREE)) {
spin_unlock(&old->i_lock);
continue;
}
break;
}
if (likely(!old)) {
spin_lock(&inode->i_lock);
inode->i_state |= I_NEW | I_CREATING;
hlist_add_head_rcu(&inode->i_hash, head);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
return 0;
}
if (unlikely(old->i_state & I_CREATING)) {
spin_unlock(&old->i_lock);
spin_unlock(&inode_hash_lock);
return -EBUSY;
}
__iget(old);
spin_unlock(&old->i_lock);
spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
return -EBUSY;
}
iput(old);
}
}
EXPORT_SYMBOL(insert_inode_locked);
int insert_inode_locked4(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct inode *old;
inode->i_state |= I_CREATING;
old = inode_insert5(inode, hashval, test, NULL, data);
if (old != inode) {
iput(old);
return -EBUSY;
}
return 0;
}
EXPORT_SYMBOL(insert_inode_locked4);
int generic_delete_inode(struct inode *inode)
{
return 1;
}
EXPORT_SYMBOL(generic_delete_inode);
/*
* Called when we're dropping the last reference
* to an inode.
*
* Call the FS "drop_inode()" function, defaulting to
* the legacy UNIX filesystem behaviour. If it tells
* us to evict inode, do so. Otherwise, retain inode
* in cache if fs is alive, sync and evict if fs is
* shutting down.
*/
static void iput_final(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
const struct super_operations *op = inode->i_sb->s_op;
unsigned long state;
int drop;
WARN_ON(inode->i_state & I_NEW);
if (op->drop_inode)
drop = op->drop_inode(inode);
else
drop = generic_drop_inode(inode);
if (!drop &&
!(inode->i_state & I_DONTCACHE) &&
(sb->s_flags & SB_ACTIVE)) {
__inode_add_lru(inode, true);
spin_unlock(&inode->i_lock);
return;
}
state = inode->i_state;
if (!drop) {
WRITE_ONCE(inode->i_state, state | I_WILL_FREE);
spin_unlock(&inode->i_lock);
write_inode_now(inode, 1);
spin_lock(&inode->i_lock);
state = inode->i_state;
WARN_ON(state & I_NEW);
state &= ~I_WILL_FREE;
}
WRITE_ONCE(inode->i_state, state | I_FREEING);
if (!list_empty(&inode->i_lru))
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
evict(inode);
}
/**
* iput - put an inode
* @inode: inode to put
*
* Puts an inode, dropping its usage count. If the inode use count hits
* zero, the inode is then freed and may also be destroyed.
*
* Consequently, iput() can sleep.
*/
void iput(struct inode *inode)
{
if (!inode)
return;
BUG_ON(inode->i_state & I_CLEAR);
retry:
if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) {
if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) {
atomic_inc(&inode->i_count);
spin_unlock(&inode->i_lock);
trace_writeback_lazytime_iput(inode);
mark_inode_dirty_sync(inode);
goto retry;
}
iput_final(inode);
}
}
EXPORT_SYMBOL(iput);
#ifdef CONFIG_BLOCK
/**
* bmap - find a block number in a file
* @inode: inode owning the block number being requested
* @block: pointer containing the block to find
*
* Replaces the value in ``*block`` with the block number on the device holding
* corresponding to the requested block number in the file.
* That is, asked for block 4 of inode 1 the function will replace the
* 4 in ``*block``, with disk block relative to the disk start that holds that
* block of the file.
*
* Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a
* hole, returns 0 and ``*block`` is also set to 0.
*/
int bmap(struct inode *inode, sector_t *block)
{
if (!inode->i_mapping->a_ops->bmap)
return -EINVAL;
*block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block);
return 0;
}
EXPORT_SYMBOL(bmap);
#endif
/*
* With relative atime, only update atime if the previous atime is
* earlier than or equal to either the ctime or mtime,
* or if at least a day has passed since the last atime update.
*/
static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
struct timespec64 now)
{
struct timespec64 ctime;
if (!(mnt->mnt_flags & MNT_RELATIME))
return 1;
/*
* Is mtime younger than or equal to atime? If yes, update atime:
*/
if (timespec64_compare(&inode->i_mtime, &inode->i_atime) >= 0)
return 1;
/*
* Is ctime younger than or equal to atime? If yes, update atime:
*/
ctime = inode_get_ctime(inode);
if (timespec64_compare(&ctime, &inode->i_atime) >= 0)
return 1;
/*
* Is the previous atime value older than a day? If yes,
* update atime:
*/
if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
return 1;
/*
* Good, we can skip the atime update:
*/
return 0;
}
/**
* inode_update_timestamps - update the timestamps on the inode
* @inode: inode to be updated
* @flags: S_* flags that needed to be updated
*
* The update_time function is called when an inode's timestamps need to be
* updated for a read or write operation. This function handles updating the
* actual timestamps. It's up to the caller to ensure that the inode is marked
* dirty appropriately.
*
* In the case where any of S_MTIME, S_CTIME, or S_VERSION need to be updated,
* attempt to update all three of them. S_ATIME updates can be handled
* independently of the rest.
*
* Returns a set of S_* flags indicating which values changed.
*/
int inode_update_timestamps(struct inode *inode, int flags)
{
int updated = 0;
struct timespec64 now;
if (flags & (S_MTIME|S_CTIME|S_VERSION)) {
struct timespec64 ctime = inode_get_ctime(inode);
now = inode_set_ctime_current(inode);
if (!timespec64_equal(&now, &ctime))
updated |= S_CTIME;
if (!timespec64_equal(&now, &inode->i_mtime)) {
inode->i_mtime = now;
updated |= S_MTIME;
}
if (IS_I_VERSION(inode) && inode_maybe_inc_iversion(inode, updated))
updated |= S_VERSION;
} else {
now = current_time(inode);
}
if (flags & S_ATIME) {
if (!timespec64_equal(&now, &inode->i_atime)) {
inode->i_atime = now;
updated |= S_ATIME;
}
}
return updated;
}
EXPORT_SYMBOL(inode_update_timestamps);
/**
* generic_update_time - update the timestamps on the inode
* @inode: inode to be updated
* @flags: S_* flags that needed to be updated
*
* The update_time function is called when an inode's timestamps need to be
* updated for a read or write operation. In the case where any of S_MTIME, S_CTIME,
* or S_VERSION need to be updated we attempt to update all three of them. S_ATIME
* updates can be handled done independently of the rest.
*
* Returns a S_* mask indicating which fields were updated.
*/
int generic_update_time(struct inode *inode, int flags)
{
int updated = inode_update_timestamps(inode, flags);
int dirty_flags = 0;
if (updated & (S_ATIME|S_MTIME|S_CTIME))
dirty_flags = inode->i_sb->s_flags & SB_LAZYTIME ? I_DIRTY_TIME : I_DIRTY_SYNC;
if (updated & S_VERSION)
dirty_flags |= I_DIRTY_SYNC;
__mark_inode_dirty(inode, dirty_flags);
return updated;
}
EXPORT_SYMBOL(generic_update_time);
/*
* This does the actual work of updating an inodes time or version. Must have
* had called mnt_want_write() before calling this.
*/
int inode_update_time(struct inode *inode, int flags)
{
if (inode->i_op->update_time)
return inode->i_op->update_time(inode, flags);
generic_update_time(inode, flags);
return 0;
}
EXPORT_SYMBOL(inode_update_time);
/**
* atime_needs_update - update the access time
* @path: the &struct path to update
* @inode: inode to update
*
* Update the accessed time on an inode and mark it for writeback.
* This function automatically handles read only file systems and media,
* as well as the "noatime" flag and inode specific "noatime" markers.
*/
bool atime_needs_update(const struct path *path, struct inode *inode)
{
struct vfsmount *mnt = path->mnt;
struct timespec64 now;
if (inode->i_flags & S_NOATIME)
return false;
/* Atime updates will likely cause i_uid and i_gid to be written
* back improprely if their true value is unknown to the vfs.
*/
if (HAS_UNMAPPED_ID(mnt_idmap(mnt), inode))
return false;
if (IS_NOATIME(inode))
return false;
if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode))
return false;
if (mnt->mnt_flags & MNT_NOATIME)
return false;
if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
return false;
now = current_time(inode);
if (!relatime_need_update(mnt, inode, now))
return false;
if (timespec64_equal(&inode->i_atime, &now))
return false;
return true;
}
void touch_atime(const struct path *path)
{
struct vfsmount *mnt = path->mnt;
struct inode *inode = d_inode(path->dentry);
if (!atime_needs_update(path, inode))
return;
if (!sb_start_write_trylock(inode->i_sb))
return;
if (__mnt_want_write(mnt) != 0)
goto skip_update;
/*
* File systems can error out when updating inodes if they need to
* allocate new space to modify an inode (such is the case for
* Btrfs), but since we touch atime while walking down the path we
* really don't care if we failed to update the atime of the file,
* so just ignore the return value.
* We may also fail on filesystems that have the ability to make parts
* of the fs read only, e.g. subvolumes in Btrfs.
*/
inode_update_time(inode, S_ATIME);
__mnt_drop_write(mnt);
skip_update:
sb_end_write(inode->i_sb);
}
EXPORT_SYMBOL(touch_atime);
/*
* Return mask of changes for notify_change() that need to be done as a
* response to write or truncate. Return 0 if nothing has to be changed.
* Negative value on error (change should be denied).
*/
int dentry_needs_remove_privs(struct mnt_idmap *idmap,
struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
int mask = 0;
int ret;
if (IS_NOSEC(inode))
return 0;
mask = setattr_should_drop_suidgid(idmap, inode);
ret = security_inode_need_killpriv(dentry);
if (ret < 0)
return ret;
if (ret)
mask |= ATTR_KILL_PRIV;
return mask;
}
static int __remove_privs(struct mnt_idmap *idmap,
struct dentry *dentry, int kill)
{
struct iattr newattrs;
newattrs.ia_valid = ATTR_FORCE | kill;
/*
* Note we call this on write, so notify_change will not
* encounter any conflicting delegations:
*/
return notify_change(idmap, dentry, &newattrs, NULL);
}
static int __file_remove_privs(struct file *file, unsigned int flags)
{
struct dentry *dentry = file_dentry(file);
struct inode *inode = file_inode(file);
int error = 0;
int kill;
if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
return 0;
kill = dentry_needs_remove_privs(file_mnt_idmap(file), dentry);
if (kill < 0)
return kill;
if (kill) {
if (flags & IOCB_NOWAIT)
return -EAGAIN;
error = __remove_privs(file_mnt_idmap(file), dentry, kill);
}
if (!error)
inode_has_no_xattr(inode);
return error;
}
/**
* file_remove_privs - remove special file privileges (suid, capabilities)
* @file: file to remove privileges from
*
* When file is modified by a write or truncation ensure that special
* file privileges are removed.
*
* Return: 0 on success, negative errno on failure.
*/
int file_remove_privs(struct file *file)
{
return __file_remove_privs(file, 0);
}
EXPORT_SYMBOL(file_remove_privs);
static int inode_needs_update_time(struct inode *inode)
{
int sync_it = 0;
struct timespec64 now = current_time(inode);
struct timespec64 ctime;
/* First try to exhaust all avenues to not sync */
if (IS_NOCMTIME(inode))
return 0;
if (!timespec64_equal(&inode->i_mtime, &now))
sync_it = S_MTIME;
ctime = inode_get_ctime(inode);
if (!timespec64_equal(&ctime, &now))
sync_it |= S_CTIME;
if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
sync_it |= S_VERSION;
return sync_it;
}
static int __file_update_time(struct file *file, int sync_mode)
{
int ret = 0;
struct inode *inode = file_inode(file);
/* try to update time settings */
if (!__mnt_want_write_file(file)) {
ret = inode_update_time(inode, sync_mode);
__mnt_drop_write_file(file);
}
return ret;
}
/**
* file_update_time - update mtime and ctime time
* @file: file accessed
*
* Update the mtime and ctime members of an inode and mark the inode for
* writeback. Note that this function is meant exclusively for usage in
* the file write path of filesystems, and filesystems may choose to
* explicitly ignore updates via this function with the _NOCMTIME inode
* flag, e.g. for network filesystem where these imestamps are handled
* by the server. This can return an error for file systems who need to
* allocate space in order to update an inode.
*
* Return: 0 on success, negative errno on failure.
*/
int file_update_time(struct file *file)
{
int ret;
struct inode *inode = file_inode(file);
ret = inode_needs_update_time(inode);
if (ret <= 0)
return ret;
return __file_update_time(file, ret);
}
EXPORT_SYMBOL(file_update_time);
/**
* file_modified_flags - handle mandated vfs changes when modifying a file
* @file: file that was modified
* @flags: kiocb flags
*
* When file has been modified ensure that special
* file privileges are removed and time settings are updated.
*
* If IOCB_NOWAIT is set, special file privileges will not be removed and
* time settings will not be updated. It will return -EAGAIN.
*
* Context: Caller must hold the file's inode lock.
*
* Return: 0 on success, negative errno on failure.
*/
static int file_modified_flags(struct file *file, int flags)
{
int ret;
struct inode *inode = file_inode(file);
/*
* Clear the security bits if the process is not being run by root.
* This keeps people from modifying setuid and setgid binaries.
*/
ret = __file_remove_privs(file, flags);
if (ret)
return ret;
if (unlikely(file->f_mode & FMODE_NOCMTIME))
return 0;
ret = inode_needs_update_time(inode);
if (ret <= 0)
return ret;
if (flags & IOCB_NOWAIT)
return -EAGAIN;
return __file_update_time(file, ret);
}
/**
* file_modified - handle mandated vfs changes when modifying a file
* @file: file that was modified
*
* When file has been modified ensure that special
* file privileges are removed and time settings are updated.
*
* Context: Caller must hold the file's inode lock.
*
* Return: 0 on success, negative errno on failure.
*/
int file_modified(struct file *file)
{
return file_modified_flags(file, 0);
}
EXPORT_SYMBOL(file_modified);
/**
* kiocb_modified - handle mandated vfs changes when modifying a file
* @iocb: iocb that was modified
*
* When file has been modified ensure that special
* file privileges are removed and time settings are updated.
*
* Context: Caller must hold the file's inode lock.
*
* Return: 0 on success, negative errno on failure.
*/
int kiocb_modified(struct kiocb *iocb)
{
return file_modified_flags(iocb->ki_filp, iocb->ki_flags);
}
EXPORT_SYMBOL_GPL(kiocb_modified);
int inode_needs_sync(struct inode *inode)
{
if (IS_SYNC(inode))
return 1;
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
return 1;
return 0;
}
EXPORT_SYMBOL(inode_needs_sync);
/*
* If we try to find an inode in the inode hash while it is being
* deleted, we have to wait until the filesystem completes its
* deletion before reporting that it isn't found. This function waits
* until the deletion _might_ have completed. Callers are responsible
* to recheck inode state.
*
* It doesn't matter if I_NEW is not set initially, a call to
* wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
* will DTRT.
*/
static void __wait_on_freeing_inode(struct inode *inode)
{
wait_queue_head_t *wq;
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_hash_lock);
schedule();
finish_wait(wq, &wait.wq_entry);
spin_lock(&inode_hash_lock);
}
static __initdata unsigned long ihash_entries;
static int __init set_ihash_entries(char *str)
{
if (!str)
return 0;
ihash_entries = simple_strtoul(str, &str, 0);
return 1;
}
__setup("ihash_entries=", set_ihash_entries);
/*
* Initialize the waitqueues and inode hash table.
*/
void __init inode_init_early(void)
{
/* If hashes are distributed across NUMA nodes, defer
* hash allocation until vmalloc space is available.
*/
if (hashdist)
return;
inode_hashtable =
alloc_large_system_hash("Inode-cache",
sizeof(struct hlist_head),
ihash_entries,
14,
HASH_EARLY | HASH_ZERO,
&i_hash_shift,
&i_hash_mask,
0,
0);
}
void __init inode_init(void)
{
/* inode slab cache */
inode_cachep = kmem_cache_create("inode_cache",
sizeof(struct inode),
0,
(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
init_once);
/* Hash may have been set up in inode_init_early */
if (!hashdist)
return;
inode_hashtable =
alloc_large_system_hash("Inode-cache",
sizeof(struct hlist_head),
ihash_entries,
14,
HASH_ZERO,
&i_hash_shift,
&i_hash_mask,
0,
0);
}
void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
{
inode->i_mode = mode;
if (S_ISCHR(mode)) {
inode->i_fop = &def_chr_fops;
inode->i_rdev = rdev;
} else if (S_ISBLK(mode)) {
if (IS_ENABLED(CONFIG_BLOCK))
inode->i_fop = &def_blk_fops;
inode->i_rdev = rdev;
} else if (S_ISFIFO(mode))
inode->i_fop = &pipefifo_fops;
else if (S_ISSOCK(mode))
; /* leave it no_open_fops */
else
printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
" inode %s:%lu\n", mode, inode->i_sb->s_id,
inode->i_ino);
}
EXPORT_SYMBOL(init_special_inode);
/**
* inode_init_owner - Init uid,gid,mode for new inode according to posix standards
* @idmap: idmap of the mount the inode was created from
* @inode: New inode
* @dir: Directory inode
* @mode: mode of the new inode
*
* If the inode has been created through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions
* and initializing i_uid and i_gid. On non-idmapped mounts or if permission
* checking is to be performed on the raw inode simply pass @nop_mnt_idmap.
*/
void inode_init_owner(struct mnt_idmap *idmap, struct inode *inode,
const struct inode *dir, umode_t mode)
{
inode_fsuid_set(inode, idmap);
if (dir && dir->i_mode & S_ISGID) {
inode->i_gid = dir->i_gid;
/* Directories are special, and always inherit S_ISGID */
if (S_ISDIR(mode))
mode |= S_ISGID;
} else
inode_fsgid_set(inode, idmap);
inode->i_mode = mode;
}
EXPORT_SYMBOL(inode_init_owner);
/**
* inode_owner_or_capable - check current task permissions to inode
* @idmap: idmap of the mount the inode was found from
* @inode: inode being checked
*
* Return true if current either has CAP_FOWNER in a namespace with the
* inode owner uid mapped, or owns the file.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
bool inode_owner_or_capable(struct mnt_idmap *idmap,
const struct inode *inode)
{
vfsuid_t vfsuid;
struct user_namespace *ns;
vfsuid = i_uid_into_vfsuid(idmap, inode);
if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
return true;
ns = current_user_ns();
if (vfsuid_has_mapping(ns, vfsuid) && ns_capable(ns, CAP_FOWNER))
return true;
return false;
}
EXPORT_SYMBOL(inode_owner_or_capable);
/*
* Direct i/o helper functions
*/
static void __inode_dio_wait(struct inode *inode)
{
wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
do {
prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE);
if (atomic_read(&inode->i_dio_count))
schedule();
} while (atomic_read(&inode->i_dio_count));
finish_wait(wq, &q.wq_entry);
}
/**
* inode_dio_wait - wait for outstanding DIO requests to finish
* @inode: inode to wait for
*
* Waits for all pending direct I/O requests to finish so that we can
* proceed with a truncate or equivalent operation.
*
* Must be called under a lock that serializes taking new references
* to i_dio_count, usually by inode->i_mutex.
*/
void inode_dio_wait(struct inode *inode)
{
if (atomic_read(&inode->i_dio_count))
__inode_dio_wait(inode);
}
EXPORT_SYMBOL(inode_dio_wait);
/*
* inode_set_flags - atomically set some inode flags
*
* Note: the caller should be holding i_mutex, or else be sure that
* they have exclusive access to the inode structure (i.e., while the
* inode is being instantiated). The reason for the cmpxchg() loop
* --- which wouldn't be necessary if all code paths which modify
* i_flags actually followed this rule, is that there is at least one
* code path which doesn't today so we use cmpxchg() out of an abundance
* of caution.
*
* In the long run, i_mutex is overkill, and we should probably look
* at using the i_lock spinlock to protect i_flags, and then make sure
* it is so documented in include/linux/fs.h and that all code follows
* the locking convention!!
*/
void inode_set_flags(struct inode *inode, unsigned int flags,
unsigned int mask)
{
WARN_ON_ONCE(flags & ~mask);
set_mask_bits(&inode->i_flags, mask, flags);
}
EXPORT_SYMBOL(inode_set_flags);
void inode_nohighmem(struct inode *inode)
{
mapping_set_gfp_mask(inode->i_mapping, GFP_USER);
}
EXPORT_SYMBOL(inode_nohighmem);
/**
* timestamp_truncate - Truncate timespec to a granularity
* @t: Timespec
* @inode: inode being updated
*
* Truncate a timespec to the granularity supported by the fs
* containing the inode. Always rounds down. gran must
* not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
*/
struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode)
{
struct super_block *sb = inode->i_sb;
unsigned int gran = sb->s_time_gran;
t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max);
if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min))
t.tv_nsec = 0;
/* Avoid division in the common cases 1 ns and 1 s. */
if (gran == 1)
; /* nothing */
else if (gran == NSEC_PER_SEC)
t.tv_nsec = 0;
else if (gran > 1 && gran < NSEC_PER_SEC)
t.tv_nsec -= t.tv_nsec % gran;
else
WARN(1, "invalid file time granularity: %u", gran);
return t;
}
EXPORT_SYMBOL(timestamp_truncate);
/**
* current_time - Return FS time
* @inode: inode.
*
* Return the current time truncated to the time granularity supported by
* the fs.
*
* Note that inode and inode->sb cannot be NULL.
* Otherwise, the function warns and returns time without truncation.
*/
struct timespec64 current_time(struct inode *inode)
{
struct timespec64 now;
ktime_get_coarse_real_ts64(&now);
return timestamp_truncate(now, inode);
}
EXPORT_SYMBOL(current_time);
/**
* inode_set_ctime_current - set the ctime to current_time
* @inode: inode
*
* Set the inode->i_ctime to the current value for the inode. Returns
* the current value that was assigned to i_ctime.
*/
struct timespec64 inode_set_ctime_current(struct inode *inode)
{
struct timespec64 now = current_time(inode);
inode_set_ctime(inode, now.tv_sec, now.tv_nsec);
return now;
}
EXPORT_SYMBOL(inode_set_ctime_current);
/**
* in_group_or_capable - check whether caller is CAP_FSETID privileged
* @idmap: idmap of the mount @inode was found from
* @inode: inode to check
* @vfsgid: the new/current vfsgid of @inode
*
* Check wether @vfsgid is in the caller's group list or if the caller is
* privileged with CAP_FSETID over @inode. This can be used to determine
* whether the setgid bit can be kept or must be dropped.
*
* Return: true if the caller is sufficiently privileged, false if not.
*/
bool in_group_or_capable(struct mnt_idmap *idmap,
const struct inode *inode, vfsgid_t vfsgid)
{
if (vfsgid_in_group_p(vfsgid))
return true;
if (capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))
return true;
return false;
}
/**
* mode_strip_sgid - handle the sgid bit for non-directories
* @idmap: idmap of the mount the inode was created from
* @dir: parent directory inode
* @mode: mode of the file to be created in @dir
*
* If the @mode of the new file has both the S_ISGID and S_IXGRP bit
* raised and @dir has the S_ISGID bit raised ensure that the caller is
* either in the group of the parent directory or they have CAP_FSETID
* in their user namespace and are privileged over the parent directory.
* In all other cases, strip the S_ISGID bit from @mode.
*
* Return: the new mode to use for the file
*/
umode_t mode_strip_sgid(struct mnt_idmap *idmap,
const struct inode *dir, umode_t mode)
{
if ((mode & (S_ISGID | S_IXGRP)) != (S_ISGID | S_IXGRP))
return mode;
if (S_ISDIR(mode) || !dir || !(dir->i_mode & S_ISGID))
return mode;
if (in_group_or_capable(idmap, dir, i_gid_into_vfsgid(idmap, dir)))
return mode;
return mode & ~S_ISGID;
}
EXPORT_SYMBOL(mode_strip_sgid);
| linux-master | fs/inode.c |
// SPDX-License-Identifier: GPL-2.0
/*
* fs/signalfd.c
*
* Copyright (C) 2003 Linus Torvalds
*
* Mon Mar 5, 2007: Davide Libenzi <[email protected]>
* Changed ->read() to return a siginfo strcture instead of signal number.
* Fixed locking in ->poll().
* Added sighand-detach notification.
* Added fd re-use in sys_signalfd() syscall.
* Now using anonymous inode source.
* Thanks to Oleg Nesterov for useful code review and suggestions.
* More comments and suggestions from Arnd Bergmann.
* Sat May 19, 2007: Davi E. M. Arnaut <[email protected]>
* Retrieve multiple signals with one read() call
* Sun Jul 15, 2007: Davide Libenzi <[email protected]>
* Attach to the sighand only during read() and poll().
*/
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/list.h>
#include <linux/anon_inodes.h>
#include <linux/signalfd.h>
#include <linux/syscalls.h>
#include <linux/proc_fs.h>
#include <linux/compat.h>
void signalfd_cleanup(struct sighand_struct *sighand)
{
wake_up_pollfree(&sighand->signalfd_wqh);
}
struct signalfd_ctx {
sigset_t sigmask;
};
static int signalfd_release(struct inode *inode, struct file *file)
{
kfree(file->private_data);
return 0;
}
static __poll_t signalfd_poll(struct file *file, poll_table *wait)
{
struct signalfd_ctx *ctx = file->private_data;
__poll_t events = 0;
poll_wait(file, ¤t->sighand->signalfd_wqh, wait);
spin_lock_irq(¤t->sighand->siglock);
if (next_signal(¤t->pending, &ctx->sigmask) ||
next_signal(¤t->signal->shared_pending,
&ctx->sigmask))
events |= EPOLLIN;
spin_unlock_irq(¤t->sighand->siglock);
return events;
}
/*
* Copied from copy_siginfo_to_user() in kernel/signal.c
*/
static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
kernel_siginfo_t const *kinfo)
{
struct signalfd_siginfo new;
BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
/*
* Unused members should be zero ...
*/
memset(&new, 0, sizeof(new));
/*
* If you change siginfo_t structure, please be sure
* this code is fixed accordingly.
*/
new.ssi_signo = kinfo->si_signo;
new.ssi_errno = kinfo->si_errno;
new.ssi_code = kinfo->si_code;
switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
case SIL_KILL:
new.ssi_pid = kinfo->si_pid;
new.ssi_uid = kinfo->si_uid;
break;
case SIL_TIMER:
new.ssi_tid = kinfo->si_tid;
new.ssi_overrun = kinfo->si_overrun;
new.ssi_ptr = (long) kinfo->si_ptr;
new.ssi_int = kinfo->si_int;
break;
case SIL_POLL:
new.ssi_band = kinfo->si_band;
new.ssi_fd = kinfo->si_fd;
break;
case SIL_FAULT_BNDERR:
case SIL_FAULT_PKUERR:
case SIL_FAULT_PERF_EVENT:
/*
* Fall through to the SIL_FAULT case. SIL_FAULT_BNDERR,
* SIL_FAULT_PKUERR, and SIL_FAULT_PERF_EVENT are only
* generated by faults that deliver them synchronously to
* userspace. In case someone injects one of these signals
* and signalfd catches it treat it as SIL_FAULT.
*/
case SIL_FAULT:
new.ssi_addr = (long) kinfo->si_addr;
break;
case SIL_FAULT_TRAPNO:
new.ssi_addr = (long) kinfo->si_addr;
new.ssi_trapno = kinfo->si_trapno;
break;
case SIL_FAULT_MCEERR:
new.ssi_addr = (long) kinfo->si_addr;
new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
break;
case SIL_CHLD:
new.ssi_pid = kinfo->si_pid;
new.ssi_uid = kinfo->si_uid;
new.ssi_status = kinfo->si_status;
new.ssi_utime = kinfo->si_utime;
new.ssi_stime = kinfo->si_stime;
break;
case SIL_RT:
/*
* This case catches also the signals queued by sigqueue().
*/
new.ssi_pid = kinfo->si_pid;
new.ssi_uid = kinfo->si_uid;
new.ssi_ptr = (long) kinfo->si_ptr;
new.ssi_int = kinfo->si_int;
break;
case SIL_SYS:
new.ssi_call_addr = (long) kinfo->si_call_addr;
new.ssi_syscall = kinfo->si_syscall;
new.ssi_arch = kinfo->si_arch;
break;
}
if (copy_to_user(uinfo, &new, sizeof(struct signalfd_siginfo)))
return -EFAULT;
return sizeof(*uinfo);
}
static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info,
int nonblock)
{
enum pid_type type;
ssize_t ret;
DECLARE_WAITQUEUE(wait, current);
spin_lock_irq(¤t->sighand->siglock);
ret = dequeue_signal(current, &ctx->sigmask, info, &type);
switch (ret) {
case 0:
if (!nonblock)
break;
ret = -EAGAIN;
fallthrough;
default:
spin_unlock_irq(¤t->sighand->siglock);
return ret;
}
add_wait_queue(¤t->sighand->signalfd_wqh, &wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
ret = dequeue_signal(current, &ctx->sigmask, info, &type);
if (ret != 0)
break;
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
spin_unlock_irq(¤t->sighand->siglock);
schedule();
spin_lock_irq(¤t->sighand->siglock);
}
spin_unlock_irq(¤t->sighand->siglock);
remove_wait_queue(¤t->sighand->signalfd_wqh, &wait);
__set_current_state(TASK_RUNNING);
return ret;
}
/*
* Returns a multiple of the size of a "struct signalfd_siginfo", or a negative
* error code. The "count" parameter must be at least the size of a
* "struct signalfd_siginfo".
*/
static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
loff_t *ppos)
{
struct signalfd_ctx *ctx = file->private_data;
struct signalfd_siginfo __user *siginfo;
int nonblock = file->f_flags & O_NONBLOCK;
ssize_t ret, total = 0;
kernel_siginfo_t info;
count /= sizeof(struct signalfd_siginfo);
if (!count)
return -EINVAL;
siginfo = (struct signalfd_siginfo __user *) buf;
do {
ret = signalfd_dequeue(ctx, &info, nonblock);
if (unlikely(ret <= 0))
break;
ret = signalfd_copyinfo(siginfo, &info);
if (ret < 0)
break;
siginfo++;
total += ret;
nonblock = 1;
} while (--count);
return total ? total: ret;
}
#ifdef CONFIG_PROC_FS
static void signalfd_show_fdinfo(struct seq_file *m, struct file *f)
{
struct signalfd_ctx *ctx = f->private_data;
sigset_t sigmask;
sigmask = ctx->sigmask;
signotset(&sigmask);
render_sigset_t(m, "sigmask:\t", &sigmask);
}
#endif
static const struct file_operations signalfd_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = signalfd_show_fdinfo,
#endif
.release = signalfd_release,
.poll = signalfd_poll,
.read = signalfd_read,
.llseek = noop_llseek,
};
static int do_signalfd4(int ufd, sigset_t *mask, int flags)
{
struct signalfd_ctx *ctx;
/* Check the SFD_* constants for consistency. */
BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK))
return -EINVAL;
sigdelsetmask(mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
signotset(mask);
if (ufd == -1) {
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->sigmask = *mask;
/*
* When we call this, the initialization must be complete, since
* anon_inode_getfd() will install the fd.
*/
ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,
O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK)));
if (ufd < 0)
kfree(ctx);
} else {
struct fd f = fdget(ufd);
if (!f.file)
return -EBADF;
ctx = f.file->private_data;
if (f.file->f_op != &signalfd_fops) {
fdput(f);
return -EINVAL;
}
spin_lock_irq(¤t->sighand->siglock);
ctx->sigmask = *mask;
spin_unlock_irq(¤t->sighand->siglock);
wake_up(¤t->sighand->signalfd_wqh);
fdput(f);
}
return ufd;
}
SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
size_t, sizemask, int, flags)
{
sigset_t mask;
if (sizemask != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&mask, user_mask, sizeof(mask)))
return -EFAULT;
return do_signalfd4(ufd, &mask, flags);
}
SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
size_t, sizemask)
{
sigset_t mask;
if (sizemask != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&mask, user_mask, sizeof(mask)))
return -EFAULT;
return do_signalfd4(ufd, &mask, 0);
}
#ifdef CONFIG_COMPAT
static long do_compat_signalfd4(int ufd,
const compat_sigset_t __user *user_mask,
compat_size_t sigsetsize, int flags)
{
sigset_t mask;
if (sigsetsize != sizeof(compat_sigset_t))
return -EINVAL;
if (get_compat_sigset(&mask, user_mask))
return -EFAULT;
return do_signalfd4(ufd, &mask, flags);
}
COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
const compat_sigset_t __user *, user_mask,
compat_size_t, sigsetsize,
int, flags)
{
return do_compat_signalfd4(ufd, user_mask, sigsetsize, flags);
}
COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
const compat_sigset_t __user *, user_mask,
compat_size_t, sigsetsize)
{
return do_compat_signalfd4(ufd, user_mask, sigsetsize, 0);
}
#endif
| linux-master | fs/signalfd.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ioctl.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/syscalls.h>
#include <linux/mm.h>
#include <linux/capability.h>
#include <linux/compat.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/uaccess.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <linux/falloc.h>
#include <linux/sched/signal.h>
#include <linux/fiemap.h>
#include <linux/mount.h>
#include <linux/fscrypt.h>
#include <linux/fileattr.h>
#include "internal.h"
#include <asm/ioctls.h>
/* So that the fiemap access checks can't overflow on 32 bit machines. */
#define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent))
/**
* vfs_ioctl - call filesystem specific ioctl methods
* @filp: open file to invoke ioctl method on
* @cmd: ioctl command to execute
* @arg: command-specific argument for ioctl
*
* Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
* returns -ENOTTY.
*
* Returns 0 on success, -errno on error.
*/
long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
int error = -ENOTTY;
if (!filp->f_op->unlocked_ioctl)
goto out;
error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
if (error == -ENOIOCTLCMD)
error = -ENOTTY;
out:
return error;
}
EXPORT_SYMBOL(vfs_ioctl);
static int ioctl_fibmap(struct file *filp, int __user *p)
{
struct inode *inode = file_inode(filp);
struct super_block *sb = inode->i_sb;
int error, ur_block;
sector_t block;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
error = get_user(ur_block, p);
if (error)
return error;
if (ur_block < 0)
return -EINVAL;
block = ur_block;
error = bmap(inode, &block);
if (block > INT_MAX) {
error = -ERANGE;
pr_warn_ratelimited("[%s/%d] FS: %s File: %pD4 would truncate fibmap result\n",
current->comm, task_pid_nr(current),
sb->s_id, filp);
}
if (error)
ur_block = 0;
else
ur_block = block;
if (put_user(ur_block, p))
error = -EFAULT;
return error;
}
/**
* fiemap_fill_next_extent - Fiemap helper function
* @fieinfo: Fiemap context passed into ->fiemap
* @logical: Extent logical start offset, in bytes
* @phys: Extent physical start offset, in bytes
* @len: Extent length, in bytes
* @flags: FIEMAP_EXTENT flags that describe this extent
*
* Called from file system ->fiemap callback. Will populate extent
* info as passed in via arguments and copy to user memory. On
* success, extent count on fieinfo is incremented.
*
* Returns 0 on success, -errno on error, 1 if this was the last
* extent that will fit in user array.
*/
int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
u64 phys, u64 len, u32 flags)
{
struct fiemap_extent extent;
struct fiemap_extent __user *dest = fieinfo->fi_extents_start;
/* only count the extents */
if (fieinfo->fi_extents_max == 0) {
fieinfo->fi_extents_mapped++;
return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
return 1;
#define SET_UNKNOWN_FLAGS (FIEMAP_EXTENT_DELALLOC)
#define SET_NO_UNMOUNTED_IO_FLAGS (FIEMAP_EXTENT_DATA_ENCRYPTED)
#define SET_NOT_ALIGNED_FLAGS (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE)
if (flags & SET_UNKNOWN_FLAGS)
flags |= FIEMAP_EXTENT_UNKNOWN;
if (flags & SET_NO_UNMOUNTED_IO_FLAGS)
flags |= FIEMAP_EXTENT_ENCODED;
if (flags & SET_NOT_ALIGNED_FLAGS)
flags |= FIEMAP_EXTENT_NOT_ALIGNED;
memset(&extent, 0, sizeof(extent));
extent.fe_logical = logical;
extent.fe_physical = phys;
extent.fe_length = len;
extent.fe_flags = flags;
dest += fieinfo->fi_extents_mapped;
if (copy_to_user(dest, &extent, sizeof(extent)))
return -EFAULT;
fieinfo->fi_extents_mapped++;
if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
return 1;
return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
}
EXPORT_SYMBOL(fiemap_fill_next_extent);
/**
* fiemap_prep - check validity of requested flags for fiemap
* @inode: Inode to operate on
* @fieinfo: Fiemap context passed into ->fiemap
* @start: Start of the mapped range
* @len: Length of the mapped range, can be truncated by this function.
* @supported_flags: Set of fiemap flags that the file system understands
*
* This function must be called from each ->fiemap instance to validate the
* fiemap request against the file system parameters.
*
* Returns 0 on success, or a negative error on failure.
*/
int fiemap_prep(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 *len, u32 supported_flags)
{
u64 maxbytes = inode->i_sb->s_maxbytes;
u32 incompat_flags;
int ret = 0;
if (*len == 0)
return -EINVAL;
if (start >= maxbytes)
return -EFBIG;
/*
* Shrink request scope to what the fs can actually handle.
*/
if (*len > maxbytes || (maxbytes - *len) < start)
*len = maxbytes - start;
supported_flags |= FIEMAP_FLAG_SYNC;
supported_flags &= FIEMAP_FLAGS_COMPAT;
incompat_flags = fieinfo->fi_flags & ~supported_flags;
if (incompat_flags) {
fieinfo->fi_flags = incompat_flags;
return -EBADR;
}
if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC)
ret = filemap_write_and_wait(inode->i_mapping);
return ret;
}
EXPORT_SYMBOL(fiemap_prep);
static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap)
{
struct fiemap fiemap;
struct fiemap_extent_info fieinfo = { 0, };
struct inode *inode = file_inode(filp);
int error;
if (!inode->i_op->fiemap)
return -EOPNOTSUPP;
if (copy_from_user(&fiemap, ufiemap, sizeof(fiemap)))
return -EFAULT;
if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
return -EINVAL;
fieinfo.fi_flags = fiemap.fm_flags;
fieinfo.fi_extents_max = fiemap.fm_extent_count;
fieinfo.fi_extents_start = ufiemap->fm_extents;
error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start,
fiemap.fm_length);
fiemap.fm_flags = fieinfo.fi_flags;
fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap)))
error = -EFAULT;
return error;
}
static long ioctl_file_clone(struct file *dst_file, unsigned long srcfd,
u64 off, u64 olen, u64 destoff)
{
struct fd src_file = fdget(srcfd);
loff_t cloned;
int ret;
if (!src_file.file)
return -EBADF;
cloned = vfs_clone_file_range(src_file.file, off, dst_file, destoff,
olen, 0);
if (cloned < 0)
ret = cloned;
else if (olen && cloned != olen)
ret = -EINVAL;
else
ret = 0;
fdput(src_file);
return ret;
}
static long ioctl_file_clone_range(struct file *file,
struct file_clone_range __user *argp)
{
struct file_clone_range args;
if (copy_from_user(&args, argp, sizeof(args)))
return -EFAULT;
return ioctl_file_clone(file, args.src_fd, args.src_offset,
args.src_length, args.dest_offset);
}
/*
* This provides compatibility with legacy XFS pre-allocation ioctls
* which predate the fallocate syscall.
*
* Only the l_start, l_len and l_whence fields of the 'struct space_resv'
* are used here, rest are ignored.
*/
static int ioctl_preallocate(struct file *filp, int mode, void __user *argp)
{
struct inode *inode = file_inode(filp);
struct space_resv sr;
if (copy_from_user(&sr, argp, sizeof(sr)))
return -EFAULT;
switch (sr.l_whence) {
case SEEK_SET:
break;
case SEEK_CUR:
sr.l_start += filp->f_pos;
break;
case SEEK_END:
sr.l_start += i_size_read(inode);
break;
default:
return -EINVAL;
}
return vfs_fallocate(filp, mode | FALLOC_FL_KEEP_SIZE, sr.l_start,
sr.l_len);
}
/* on ia32 l_start is on a 32-bit boundary */
#if defined CONFIG_COMPAT && defined(CONFIG_X86_64)
/* just account for different alignment */
static int compat_ioctl_preallocate(struct file *file, int mode,
struct space_resv_32 __user *argp)
{
struct inode *inode = file_inode(file);
struct space_resv_32 sr;
if (copy_from_user(&sr, argp, sizeof(sr)))
return -EFAULT;
switch (sr.l_whence) {
case SEEK_SET:
break;
case SEEK_CUR:
sr.l_start += file->f_pos;
break;
case SEEK_END:
sr.l_start += i_size_read(inode);
break;
default:
return -EINVAL;
}
return vfs_fallocate(file, mode | FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
}
#endif
static int file_ioctl(struct file *filp, unsigned int cmd, int __user *p)
{
switch (cmd) {
case FIBMAP:
return ioctl_fibmap(filp, p);
case FS_IOC_RESVSP:
case FS_IOC_RESVSP64:
return ioctl_preallocate(filp, 0, p);
case FS_IOC_UNRESVSP:
case FS_IOC_UNRESVSP64:
return ioctl_preallocate(filp, FALLOC_FL_PUNCH_HOLE, p);
case FS_IOC_ZERO_RANGE:
return ioctl_preallocate(filp, FALLOC_FL_ZERO_RANGE, p);
}
return -ENOIOCTLCMD;
}
static int ioctl_fionbio(struct file *filp, int __user *argp)
{
unsigned int flag;
int on, error;
error = get_user(on, argp);
if (error)
return error;
flag = O_NONBLOCK;
#ifdef __sparc__
/* SunOS compatibility item. */
if (O_NONBLOCK != O_NDELAY)
flag |= O_NDELAY;
#endif
spin_lock(&filp->f_lock);
if (on)
filp->f_flags |= flag;
else
filp->f_flags &= ~flag;
spin_unlock(&filp->f_lock);
return error;
}
static int ioctl_fioasync(unsigned int fd, struct file *filp,
int __user *argp)
{
unsigned int flag;
int on, error;
error = get_user(on, argp);
if (error)
return error;
flag = on ? FASYNC : 0;
/* Did FASYNC state change ? */
if ((flag ^ filp->f_flags) & FASYNC) {
if (filp->f_op->fasync)
/* fasync() adjusts filp->f_flags */
error = filp->f_op->fasync(fd, filp, on);
else
error = -ENOTTY;
}
return error < 0 ? error : 0;
}
static int ioctl_fsfreeze(struct file *filp)
{
struct super_block *sb = file_inode(filp)->i_sb;
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;
/* If filesystem doesn't support freeze feature, return. */
if (sb->s_op->freeze_fs == NULL && sb->s_op->freeze_super == NULL)
return -EOPNOTSUPP;
/* Freeze */
if (sb->s_op->freeze_super)
return sb->s_op->freeze_super(sb, FREEZE_HOLDER_USERSPACE);
return freeze_super(sb, FREEZE_HOLDER_USERSPACE);
}
static int ioctl_fsthaw(struct file *filp)
{
struct super_block *sb = file_inode(filp)->i_sb;
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;
/* Thaw */
if (sb->s_op->thaw_super)
return sb->s_op->thaw_super(sb, FREEZE_HOLDER_USERSPACE);
return thaw_super(sb, FREEZE_HOLDER_USERSPACE);
}
static int ioctl_file_dedupe_range(struct file *file,
struct file_dedupe_range __user *argp)
{
struct file_dedupe_range *same = NULL;
int ret;
unsigned long size;
u16 count;
if (get_user(count, &argp->dest_count)) {
ret = -EFAULT;
goto out;
}
size = offsetof(struct file_dedupe_range, info[count]);
if (size > PAGE_SIZE) {
ret = -ENOMEM;
goto out;
}
same = memdup_user(argp, size);
if (IS_ERR(same)) {
ret = PTR_ERR(same);
same = NULL;
goto out;
}
same->dest_count = count;
ret = vfs_dedupe_file_range(file, same);
if (ret)
goto out;
ret = copy_to_user(argp, same, size);
if (ret)
ret = -EFAULT;
out:
kfree(same);
return ret;
}
/**
* fileattr_fill_xflags - initialize fileattr with xflags
* @fa: fileattr pointer
* @xflags: FS_XFLAG_* flags
*
* Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags). All
* other fields are zeroed.
*/
void fileattr_fill_xflags(struct fileattr *fa, u32 xflags)
{
memset(fa, 0, sizeof(*fa));
fa->fsx_valid = true;
fa->fsx_xflags = xflags;
if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)
fa->flags |= FS_IMMUTABLE_FL;
if (fa->fsx_xflags & FS_XFLAG_APPEND)
fa->flags |= FS_APPEND_FL;
if (fa->fsx_xflags & FS_XFLAG_SYNC)
fa->flags |= FS_SYNC_FL;
if (fa->fsx_xflags & FS_XFLAG_NOATIME)
fa->flags |= FS_NOATIME_FL;
if (fa->fsx_xflags & FS_XFLAG_NODUMP)
fa->flags |= FS_NODUMP_FL;
if (fa->fsx_xflags & FS_XFLAG_DAX)
fa->flags |= FS_DAX_FL;
if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT)
fa->flags |= FS_PROJINHERIT_FL;
}
EXPORT_SYMBOL(fileattr_fill_xflags);
/**
* fileattr_fill_flags - initialize fileattr with flags
* @fa: fileattr pointer
* @flags: FS_*_FL flags
*
* Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
* All other fields are zeroed.
*/
void fileattr_fill_flags(struct fileattr *fa, u32 flags)
{
memset(fa, 0, sizeof(*fa));
fa->flags_valid = true;
fa->flags = flags;
if (fa->flags & FS_SYNC_FL)
fa->fsx_xflags |= FS_XFLAG_SYNC;
if (fa->flags & FS_IMMUTABLE_FL)
fa->fsx_xflags |= FS_XFLAG_IMMUTABLE;
if (fa->flags & FS_APPEND_FL)
fa->fsx_xflags |= FS_XFLAG_APPEND;
if (fa->flags & FS_NODUMP_FL)
fa->fsx_xflags |= FS_XFLAG_NODUMP;
if (fa->flags & FS_NOATIME_FL)
fa->fsx_xflags |= FS_XFLAG_NOATIME;
if (fa->flags & FS_DAX_FL)
fa->fsx_xflags |= FS_XFLAG_DAX;
if (fa->flags & FS_PROJINHERIT_FL)
fa->fsx_xflags |= FS_XFLAG_PROJINHERIT;
}
EXPORT_SYMBOL(fileattr_fill_flags);
/**
* vfs_fileattr_get - retrieve miscellaneous file attributes
* @dentry: the object to retrieve from
* @fa: fileattr pointer
*
* Call i_op->fileattr_get() callback, if exists.
*
* Return: 0 on success, or a negative error on failure.
*/
int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
if (!inode->i_op->fileattr_get)
return -ENOIOCTLCMD;
return inode->i_op->fileattr_get(dentry, fa);
}
EXPORT_SYMBOL(vfs_fileattr_get);
/**
* copy_fsxattr_to_user - copy fsxattr to userspace.
* @fa: fileattr pointer
* @ufa: fsxattr user pointer
*
* Return: 0 on success, or -EFAULT on failure.
*/
int copy_fsxattr_to_user(const struct fileattr *fa, struct fsxattr __user *ufa)
{
struct fsxattr xfa;
memset(&xfa, 0, sizeof(xfa));
xfa.fsx_xflags = fa->fsx_xflags;
xfa.fsx_extsize = fa->fsx_extsize;
xfa.fsx_nextents = fa->fsx_nextents;
xfa.fsx_projid = fa->fsx_projid;
xfa.fsx_cowextsize = fa->fsx_cowextsize;
if (copy_to_user(ufa, &xfa, sizeof(xfa)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(copy_fsxattr_to_user);
static int copy_fsxattr_from_user(struct fileattr *fa,
struct fsxattr __user *ufa)
{
struct fsxattr xfa;
if (copy_from_user(&xfa, ufa, sizeof(xfa)))
return -EFAULT;
fileattr_fill_xflags(fa, xfa.fsx_xflags);
fa->fsx_extsize = xfa.fsx_extsize;
fa->fsx_nextents = xfa.fsx_nextents;
fa->fsx_projid = xfa.fsx_projid;
fa->fsx_cowextsize = xfa.fsx_cowextsize;
return 0;
}
/*
* Generic function to check FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS values and reject
* any invalid configurations.
*
* Note: must be called with inode lock held.
*/
static int fileattr_set_prepare(struct inode *inode,
const struct fileattr *old_ma,
struct fileattr *fa)
{
int err;
/*
* The IMMUTABLE and APPEND_ONLY flags can only be changed by
* the relevant capability.
*/
if ((fa->flags ^ old_ma->flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
!capable(CAP_LINUX_IMMUTABLE))
return -EPERM;
err = fscrypt_prepare_setflags(inode, old_ma->flags, fa->flags);
if (err)
return err;
/*
* Project Quota ID state is only allowed to change from within the init
* namespace. Enforce that restriction only if we are trying to change
* the quota ID state. Everything else is allowed in user namespaces.
*/
if (current_user_ns() != &init_user_ns) {
if (old_ma->fsx_projid != fa->fsx_projid)
return -EINVAL;
if ((old_ma->fsx_xflags ^ fa->fsx_xflags) &
FS_XFLAG_PROJINHERIT)
return -EINVAL;
} else {
/*
* Caller is allowed to change the project ID. If it is being
* changed, make sure that the new value is valid.
*/
if (old_ma->fsx_projid != fa->fsx_projid &&
!projid_valid(make_kprojid(&init_user_ns, fa->fsx_projid)))
return -EINVAL;
}
/* Check extent size hints. */
if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
return -EINVAL;
if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
!S_ISDIR(inode->i_mode))
return -EINVAL;
if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
return -EINVAL;
/*
* It is only valid to set the DAX flag on regular files and
* directories on filesystems.
*/
if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
return -EINVAL;
/* Extent size hints of zero turn off the flags. */
if (fa->fsx_extsize == 0)
fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
if (fa->fsx_cowextsize == 0)
fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
return 0;
}
/**
* vfs_fileattr_set - change miscellaneous file attributes
* @idmap: idmap of the mount
* @dentry: the object to change
* @fa: fileattr pointer
*
* After verifying permissions, call i_op->fileattr_set() callback, if
* exists.
*
* Verifying attributes involves retrieving current attributes with
* i_op->fileattr_get(), this also allows initializing attributes that have
* not been set by the caller to current values. Inode lock is held
* thoughout to prevent racing with another instance.
*
* Return: 0 on success, or a negative error on failure.
*/
int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
struct fileattr *fa)
{
struct inode *inode = d_inode(dentry);
struct fileattr old_ma = {};
int err;
if (!inode->i_op->fileattr_set)
return -ENOIOCTLCMD;
if (!inode_owner_or_capable(idmap, inode))
return -EPERM;
inode_lock(inode);
err = vfs_fileattr_get(dentry, &old_ma);
if (!err) {
/* initialize missing bits from old_ma */
if (fa->flags_valid) {
fa->fsx_xflags |= old_ma.fsx_xflags & ~FS_XFLAG_COMMON;
fa->fsx_extsize = old_ma.fsx_extsize;
fa->fsx_nextents = old_ma.fsx_nextents;
fa->fsx_projid = old_ma.fsx_projid;
fa->fsx_cowextsize = old_ma.fsx_cowextsize;
} else {
fa->flags |= old_ma.flags & ~FS_COMMON_FL;
}
err = fileattr_set_prepare(inode, &old_ma, fa);
if (!err)
err = inode->i_op->fileattr_set(idmap, dentry, fa);
}
inode_unlock(inode);
return err;
}
EXPORT_SYMBOL(vfs_fileattr_set);
static int ioctl_getflags(struct file *file, unsigned int __user *argp)
{
struct fileattr fa = { .flags_valid = true }; /* hint only */
int err;
err = vfs_fileattr_get(file->f_path.dentry, &fa);
if (!err)
err = put_user(fa.flags, argp);
return err;
}
static int ioctl_setflags(struct file *file, unsigned int __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
struct fileattr fa;
unsigned int flags;
int err;
err = get_user(flags, argp);
if (!err) {
err = mnt_want_write_file(file);
if (!err) {
fileattr_fill_flags(&fa, flags);
err = vfs_fileattr_set(idmap, dentry, &fa);
mnt_drop_write_file(file);
}
}
return err;
}
static int ioctl_fsgetxattr(struct file *file, void __user *argp)
{
struct fileattr fa = { .fsx_valid = true }; /* hint only */
int err;
err = vfs_fileattr_get(file->f_path.dentry, &fa);
if (!err)
err = copy_fsxattr_to_user(&fa, argp);
return err;
}
static int ioctl_fssetxattr(struct file *file, void __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
struct fileattr fa;
int err;
err = copy_fsxattr_from_user(&fa, argp);
if (!err) {
err = mnt_want_write_file(file);
if (!err) {
err = vfs_fileattr_set(idmap, dentry, &fa);
mnt_drop_write_file(file);
}
}
return err;
}
/*
* do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
* It's just a simple helper for sys_ioctl and compat_sys_ioctl.
*
* When you add any new common ioctls to the switches above and below,
* please ensure they have compatible arguments in compat mode.
*/
static int do_vfs_ioctl(struct file *filp, unsigned int fd,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
struct inode *inode = file_inode(filp);
switch (cmd) {
case FIOCLEX:
set_close_on_exec(fd, 1);
return 0;
case FIONCLEX:
set_close_on_exec(fd, 0);
return 0;
case FIONBIO:
return ioctl_fionbio(filp, argp);
case FIOASYNC:
return ioctl_fioasync(fd, filp, argp);
case FIOQSIZE:
if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) ||
S_ISLNK(inode->i_mode)) {
loff_t res = inode_get_bytes(inode);
return copy_to_user(argp, &res, sizeof(res)) ?
-EFAULT : 0;
}
return -ENOTTY;
case FIFREEZE:
return ioctl_fsfreeze(filp);
case FITHAW:
return ioctl_fsthaw(filp);
case FS_IOC_FIEMAP:
return ioctl_fiemap(filp, argp);
case FIGETBSZ:
/* anon_bdev filesystems may not have a block size */
if (!inode->i_sb->s_blocksize)
return -EINVAL;
return put_user(inode->i_sb->s_blocksize, (int __user *)argp);
case FICLONE:
return ioctl_file_clone(filp, arg, 0, 0, 0);
case FICLONERANGE:
return ioctl_file_clone_range(filp, argp);
case FIDEDUPERANGE:
return ioctl_file_dedupe_range(filp, argp);
case FIONREAD:
if (!S_ISREG(inode->i_mode))
return vfs_ioctl(filp, cmd, arg);
return put_user(i_size_read(inode) - filp->f_pos,
(int __user *)argp);
case FS_IOC_GETFLAGS:
return ioctl_getflags(filp, argp);
case FS_IOC_SETFLAGS:
return ioctl_setflags(filp, argp);
case FS_IOC_FSGETXATTR:
return ioctl_fsgetxattr(filp, argp);
case FS_IOC_FSSETXATTR:
return ioctl_fssetxattr(filp, argp);
default:
if (S_ISREG(inode->i_mode))
return file_ioctl(filp, cmd, argp);
break;
}
return -ENOIOCTLCMD;
}
SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
{
struct fd f = fdget(fd);
int error;
if (!f.file)
return -EBADF;
error = security_file_ioctl(f.file, cmd, arg);
if (error)
goto out;
error = do_vfs_ioctl(f.file, fd, cmd, arg);
if (error == -ENOIOCTLCMD)
error = vfs_ioctl(f.file, cmd, arg);
out:
fdput(f);
return error;
}
#ifdef CONFIG_COMPAT
/**
* compat_ptr_ioctl - generic implementation of .compat_ioctl file operation
* @file: The file to operate on.
* @cmd: The ioctl command number.
* @arg: The argument to the ioctl.
*
* This is not normally called as a function, but instead set in struct
* file_operations as
*
* .compat_ioctl = compat_ptr_ioctl,
*
* On most architectures, the compat_ptr_ioctl() just passes all arguments
* to the corresponding ->ioctl handler. The exception is arch/s390, where
* compat_ptr() clears the top bit of a 32-bit pointer value, so user space
* pointers to the second 2GB alias the first 2GB, as is the case for
* native 32-bit s390 user space.
*
* The compat_ptr_ioctl() function must therefore be used only with ioctl
* functions that either ignore the argument or pass a pointer to a
* compatible data type.
*
* If any ioctl command handled by fops->unlocked_ioctl passes a plain
* integer instead of a pointer, or any of the passed data types
* is incompatible between 32-bit and 64-bit architectures, a proper
* handler is required instead of compat_ptr_ioctl.
*/
long compat_ptr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
if (!file->f_op->unlocked_ioctl)
return -ENOIOCTLCMD;
return file->f_op->unlocked_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
EXPORT_SYMBOL(compat_ptr_ioctl);
COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
compat_ulong_t, arg)
{
struct fd f = fdget(fd);
int error;
if (!f.file)
return -EBADF;
/* RED-PEN how should LSM module know it's handling 32bit? */
error = security_file_ioctl(f.file, cmd, arg);
if (error)
goto out;
switch (cmd) {
/* FICLONE takes an int argument, so don't use compat_ptr() */
case FICLONE:
error = ioctl_file_clone(f.file, arg, 0, 0, 0);
break;
#if defined(CONFIG_X86_64)
/* these get messy on amd64 due to alignment differences */
case FS_IOC_RESVSP_32:
case FS_IOC_RESVSP64_32:
error = compat_ioctl_preallocate(f.file, 0, compat_ptr(arg));
break;
case FS_IOC_UNRESVSP_32:
case FS_IOC_UNRESVSP64_32:
error = compat_ioctl_preallocate(f.file, FALLOC_FL_PUNCH_HOLE,
compat_ptr(arg));
break;
case FS_IOC_ZERO_RANGE_32:
error = compat_ioctl_preallocate(f.file, FALLOC_FL_ZERO_RANGE,
compat_ptr(arg));
break;
#endif
/*
* These access 32-bit values anyway so no further handling is
* necessary.
*/
case FS_IOC32_GETFLAGS:
case FS_IOC32_SETFLAGS:
cmd = (cmd == FS_IOC32_GETFLAGS) ?
FS_IOC_GETFLAGS : FS_IOC_SETFLAGS;
fallthrough;
/*
* everything else in do_vfs_ioctl() takes either a compatible
* pointer argument or no argument -- call it with a modified
* argument.
*/
default:
error = do_vfs_ioctl(f.file, fd, cmd,
(unsigned long)compat_ptr(arg));
if (error != -ENOIOCTLCMD)
break;
if (f.file->f_op->compat_ioctl)
error = f.file->f_op->compat_ioctl(f.file, cmd, arg);
if (error == -ENOIOCTLCMD)
error = -ENOTTY;
break;
}
out:
fdput(f);
return error;
}
#endif
| linux-master | fs/ioctl.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/libfs.c
* Library for filesystems writers.
*/
#include <linux/blkdev.h>
#include <linux/export.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/mount.h>
#include <linux/vfs.h>
#include <linux/quotaops.h>
#include <linux/mutex.h>
#include <linux/namei.h>
#include <linux/exportfs.h>
#include <linux/iversion.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* sync_mapping_buffers */
#include <linux/fs_context.h>
#include <linux/pseudo_fs.h>
#include <linux/fsnotify.h>
#include <linux/unicode.h>
#include <linux/fscrypt.h>
#include <linux/uaccess.h>
#include "internal.h"
int simple_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, u32 request_mask,
unsigned int query_flags)
{
struct inode *inode = d_inode(path->dentry);
generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
return 0;
}
EXPORT_SYMBOL(simple_getattr);
int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
{
buf->f_type = dentry->d_sb->s_magic;
buf->f_bsize = PAGE_SIZE;
buf->f_namelen = NAME_MAX;
return 0;
}
EXPORT_SYMBOL(simple_statfs);
/*
* Retaining negative dentries for an in-memory filesystem just wastes
* memory and lookup time: arrange for them to be deleted immediately.
*/
int always_delete_dentry(const struct dentry *dentry)
{
return 1;
}
EXPORT_SYMBOL(always_delete_dentry);
const struct dentry_operations simple_dentry_operations = {
.d_delete = always_delete_dentry,
};
EXPORT_SYMBOL(simple_dentry_operations);
/*
* Lookup the data. This is trivial - if the dentry didn't already
* exist, we know it is negative. Set d_op to delete negative dentries.
*/
struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
if (dentry->d_name.len > NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);
if (!dentry->d_sb->s_d_op)
d_set_d_op(dentry, &simple_dentry_operations);
d_add(dentry, NULL);
return NULL;
}
EXPORT_SYMBOL(simple_lookup);
int dcache_dir_open(struct inode *inode, struct file *file)
{
file->private_data = d_alloc_cursor(file->f_path.dentry);
return file->private_data ? 0 : -ENOMEM;
}
EXPORT_SYMBOL(dcache_dir_open);
int dcache_dir_close(struct inode *inode, struct file *file)
{
dput(file->private_data);
return 0;
}
EXPORT_SYMBOL(dcache_dir_close);
/* parent is locked at least shared */
/*
* Returns an element of siblings' list.
* We are looking for <count>th positive after <p>; if
* found, dentry is grabbed and returned to caller.
* If no such element exists, NULL is returned.
*/
static struct dentry *scan_positives(struct dentry *cursor,
struct list_head *p,
loff_t count,
struct dentry *last)
{
struct dentry *dentry = cursor->d_parent, *found = NULL;
spin_lock(&dentry->d_lock);
while ((p = p->next) != &dentry->d_subdirs) {
struct dentry *d = list_entry(p, struct dentry, d_child);
// we must at least skip cursors, to avoid livelocks
if (d->d_flags & DCACHE_DENTRY_CURSOR)
continue;
if (simple_positive(d) && !--count) {
spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
if (simple_positive(d))
found = dget_dlock(d);
spin_unlock(&d->d_lock);
if (likely(found))
break;
count = 1;
}
if (need_resched()) {
list_move(&cursor->d_child, p);
p = &cursor->d_child;
spin_unlock(&dentry->d_lock);
cond_resched();
spin_lock(&dentry->d_lock);
}
}
spin_unlock(&dentry->d_lock);
dput(last);
return found;
}
loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
{
struct dentry *dentry = file->f_path.dentry;
switch (whence) {
case 1:
offset += file->f_pos;
fallthrough;
case 0:
if (offset >= 0)
break;
fallthrough;
default:
return -EINVAL;
}
if (offset != file->f_pos) {
struct dentry *cursor = file->private_data;
struct dentry *to = NULL;
inode_lock_shared(dentry->d_inode);
if (offset > 2)
to = scan_positives(cursor, &dentry->d_subdirs,
offset - 2, NULL);
spin_lock(&dentry->d_lock);
if (to)
list_move(&cursor->d_child, &to->d_child);
else
list_del_init(&cursor->d_child);
spin_unlock(&dentry->d_lock);
dput(to);
file->f_pos = offset;
inode_unlock_shared(dentry->d_inode);
}
return offset;
}
EXPORT_SYMBOL(dcache_dir_lseek);
/*
* Directory is locked and all positive dentries in it are safe, since
* for ramfs-type trees they can't go away without unlink() or rmdir(),
* both impossible due to the lock on directory.
*/
int dcache_readdir(struct file *file, struct dir_context *ctx)
{
struct dentry *dentry = file->f_path.dentry;
struct dentry *cursor = file->private_data;
struct list_head *anchor = &dentry->d_subdirs;
struct dentry *next = NULL;
struct list_head *p;
if (!dir_emit_dots(file, ctx))
return 0;
if (ctx->pos == 2)
p = anchor;
else if (!list_empty(&cursor->d_child))
p = &cursor->d_child;
else
return 0;
while ((next = scan_positives(cursor, p, 1, next)) != NULL) {
if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
d_inode(next)->i_ino,
fs_umode_to_dtype(d_inode(next)->i_mode)))
break;
ctx->pos++;
p = &next->d_child;
}
spin_lock(&dentry->d_lock);
if (next)
list_move_tail(&cursor->d_child, &next->d_child);
else
list_del_init(&cursor->d_child);
spin_unlock(&dentry->d_lock);
dput(next);
return 0;
}
EXPORT_SYMBOL(dcache_readdir);
ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
{
return -EISDIR;
}
EXPORT_SYMBOL(generic_read_dir);
const struct file_operations simple_dir_operations = {
.open = dcache_dir_open,
.release = dcache_dir_close,
.llseek = dcache_dir_lseek,
.read = generic_read_dir,
.iterate_shared = dcache_readdir,
.fsync = noop_fsync,
};
EXPORT_SYMBOL(simple_dir_operations);
const struct inode_operations simple_dir_inode_operations = {
.lookup = simple_lookup,
};
EXPORT_SYMBOL(simple_dir_inode_operations);
static void offset_set(struct dentry *dentry, u32 offset)
{
dentry->d_fsdata = (void *)((uintptr_t)(offset));
}
static u32 dentry2offset(struct dentry *dentry)
{
return (u32)((uintptr_t)(dentry->d_fsdata));
}
static struct lock_class_key simple_offset_xa_lock;
/**
* simple_offset_init - initialize an offset_ctx
* @octx: directory offset map to be initialized
*
*/
void simple_offset_init(struct offset_ctx *octx)
{
xa_init_flags(&octx->xa, XA_FLAGS_ALLOC1);
lockdep_set_class(&octx->xa.xa_lock, &simple_offset_xa_lock);
/* 0 is '.', 1 is '..', so always start with offset 2 */
octx->next_offset = 2;
}
/**
* simple_offset_add - Add an entry to a directory's offset map
* @octx: directory offset ctx to be updated
* @dentry: new dentry being added
*
* Returns zero on success. @so_ctx and the dentry offset are updated.
* Otherwise, a negative errno value is returned.
*/
int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry)
{
static const struct xa_limit limit = XA_LIMIT(2, U32_MAX);
u32 offset;
int ret;
if (dentry2offset(dentry) != 0)
return -EBUSY;
ret = xa_alloc_cyclic(&octx->xa, &offset, dentry, limit,
&octx->next_offset, GFP_KERNEL);
if (ret < 0)
return ret;
offset_set(dentry, offset);
return 0;
}
/**
* simple_offset_remove - Remove an entry to a directory's offset map
* @octx: directory offset ctx to be updated
* @dentry: dentry being removed
*
*/
void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry)
{
u32 offset;
offset = dentry2offset(dentry);
if (offset == 0)
return;
xa_erase(&octx->xa, offset);
offset_set(dentry, 0);
}
/**
* simple_offset_rename_exchange - exchange rename with directory offsets
* @old_dir: parent of dentry being moved
* @old_dentry: dentry being moved
* @new_dir: destination parent
* @new_dentry: destination dentry
*
* Returns zero on success. Otherwise a negative errno is returned and the
* rename is rolled back.
*/
int simple_offset_rename_exchange(struct inode *old_dir,
struct dentry *old_dentry,
struct inode *new_dir,
struct dentry *new_dentry)
{
struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir);
struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir);
u32 old_index = dentry2offset(old_dentry);
u32 new_index = dentry2offset(new_dentry);
int ret;
simple_offset_remove(old_ctx, old_dentry);
simple_offset_remove(new_ctx, new_dentry);
ret = simple_offset_add(new_ctx, old_dentry);
if (ret)
goto out_restore;
ret = simple_offset_add(old_ctx, new_dentry);
if (ret) {
simple_offset_remove(new_ctx, old_dentry);
goto out_restore;
}
ret = simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry);
if (ret) {
simple_offset_remove(new_ctx, old_dentry);
simple_offset_remove(old_ctx, new_dentry);
goto out_restore;
}
return 0;
out_restore:
offset_set(old_dentry, old_index);
xa_store(&old_ctx->xa, old_index, old_dentry, GFP_KERNEL);
offset_set(new_dentry, new_index);
xa_store(&new_ctx->xa, new_index, new_dentry, GFP_KERNEL);
return ret;
}
/**
* simple_offset_destroy - Release offset map
* @octx: directory offset ctx that is about to be destroyed
*
* During fs teardown (eg. umount), a directory's offset map might still
* contain entries. xa_destroy() cleans out anything that remains.
*/
void simple_offset_destroy(struct offset_ctx *octx)
{
xa_destroy(&octx->xa);
}
/**
* offset_dir_llseek - Advance the read position of a directory descriptor
* @file: an open directory whose position is to be updated
* @offset: a byte offset
* @whence: enumerator describing the starting position for this update
*
* SEEK_END, SEEK_DATA, and SEEK_HOLE are not supported for directories.
*
* Returns the updated read position if successful; otherwise a
* negative errno is returned and the read position remains unchanged.
*/
static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence)
{
switch (whence) {
case SEEK_CUR:
offset += file->f_pos;
fallthrough;
case SEEK_SET:
if (offset >= 0)
break;
fallthrough;
default:
return -EINVAL;
}
return vfs_setpos(file, offset, U32_MAX);
}
static struct dentry *offset_find_next(struct xa_state *xas)
{
struct dentry *child, *found = NULL;
rcu_read_lock();
child = xas_next_entry(xas, U32_MAX);
if (!child)
goto out;
spin_lock(&child->d_lock);
if (simple_positive(child))
found = dget_dlock(child);
spin_unlock(&child->d_lock);
out:
rcu_read_unlock();
return found;
}
static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry)
{
u32 offset = dentry2offset(dentry);
struct inode *inode = d_inode(dentry);
return ctx->actor(ctx, dentry->d_name.name, dentry->d_name.len, offset,
inode->i_ino, fs_umode_to_dtype(inode->i_mode));
}
static void offset_iterate_dir(struct inode *inode, struct dir_context *ctx)
{
struct offset_ctx *so_ctx = inode->i_op->get_offset_ctx(inode);
XA_STATE(xas, &so_ctx->xa, ctx->pos);
struct dentry *dentry;
while (true) {
dentry = offset_find_next(&xas);
if (!dentry)
break;
if (!offset_dir_emit(ctx, dentry)) {
dput(dentry);
break;
}
dput(dentry);
ctx->pos = xas.xa_index + 1;
}
}
/**
* offset_readdir - Emit entries starting at offset @ctx->pos
* @file: an open directory to iterate over
* @ctx: directory iteration context
*
* Caller must hold @file's i_rwsem to prevent insertion or removal of
* entries during this call.
*
* On entry, @ctx->pos contains an offset that represents the first entry
* to be read from the directory.
*
* The operation continues until there are no more entries to read, or
* until the ctx->actor indicates there is no more space in the caller's
* output buffer.
*
* On return, @ctx->pos contains an offset that will read the next entry
* in this directory when offset_readdir() is called again with @ctx.
*
* Return values:
* %0 - Complete
*/
static int offset_readdir(struct file *file, struct dir_context *ctx)
{
struct dentry *dir = file->f_path.dentry;
lockdep_assert_held(&d_inode(dir)->i_rwsem);
if (!dir_emit_dots(file, ctx))
return 0;
offset_iterate_dir(d_inode(dir), ctx);
return 0;
}
const struct file_operations simple_offset_dir_operations = {
.llseek = offset_dir_llseek,
.iterate_shared = offset_readdir,
.read = generic_read_dir,
.fsync = noop_fsync,
};
static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev)
{
struct dentry *child = NULL;
struct list_head *p = prev ? &prev->d_child : &parent->d_subdirs;
spin_lock(&parent->d_lock);
while ((p = p->next) != &parent->d_subdirs) {
struct dentry *d = container_of(p, struct dentry, d_child);
if (simple_positive(d)) {
spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
if (simple_positive(d))
child = dget_dlock(d);
spin_unlock(&d->d_lock);
if (likely(child))
break;
}
}
spin_unlock(&parent->d_lock);
dput(prev);
return child;
}
void simple_recursive_removal(struct dentry *dentry,
void (*callback)(struct dentry *))
{
struct dentry *this = dget(dentry);
while (true) {
struct dentry *victim = NULL, *child;
struct inode *inode = this->d_inode;
inode_lock(inode);
if (d_is_dir(this))
inode->i_flags |= S_DEAD;
while ((child = find_next_child(this, victim)) == NULL) {
// kill and ascend
// update metadata while it's still locked
inode_set_ctime_current(inode);
clear_nlink(inode);
inode_unlock(inode);
victim = this;
this = this->d_parent;
inode = this->d_inode;
inode_lock(inode);
if (simple_positive(victim)) {
d_invalidate(victim); // avoid lost mounts
if (d_is_dir(victim))
fsnotify_rmdir(inode, victim);
else
fsnotify_unlink(inode, victim);
if (callback)
callback(victim);
dput(victim); // unpin it
}
if (victim == dentry) {
inode->i_mtime = inode_set_ctime_current(inode);
if (d_is_dir(dentry))
drop_nlink(inode);
inode_unlock(inode);
dput(dentry);
return;
}
}
inode_unlock(inode);
this = child;
}
}
EXPORT_SYMBOL(simple_recursive_removal);
static const struct super_operations simple_super_operations = {
.statfs = simple_statfs,
};
static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc)
{
struct pseudo_fs_context *ctx = fc->fs_private;
struct inode *root;
s->s_maxbytes = MAX_LFS_FILESIZE;
s->s_blocksize = PAGE_SIZE;
s->s_blocksize_bits = PAGE_SHIFT;
s->s_magic = ctx->magic;
s->s_op = ctx->ops ?: &simple_super_operations;
s->s_xattr = ctx->xattr;
s->s_time_gran = 1;
root = new_inode(s);
if (!root)
return -ENOMEM;
/*
* since this is the first inode, make it number 1. New inodes created
* after this must take care not to collide with it (by passing
* max_reserved of 1 to iunique).
*/
root->i_ino = 1;
root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
root->i_atime = root->i_mtime = inode_set_ctime_current(root);
s->s_root = d_make_root(root);
if (!s->s_root)
return -ENOMEM;
s->s_d_op = ctx->dops;
return 0;
}
static int pseudo_fs_get_tree(struct fs_context *fc)
{
return get_tree_nodev(fc, pseudo_fs_fill_super);
}
static void pseudo_fs_free(struct fs_context *fc)
{
kfree(fc->fs_private);
}
static const struct fs_context_operations pseudo_fs_context_ops = {
.free = pseudo_fs_free,
.get_tree = pseudo_fs_get_tree,
};
/*
* Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
* will never be mountable)
*/
struct pseudo_fs_context *init_pseudo(struct fs_context *fc,
unsigned long magic)
{
struct pseudo_fs_context *ctx;
ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL);
if (likely(ctx)) {
ctx->magic = magic;
fc->fs_private = ctx;
fc->ops = &pseudo_fs_context_ops;
fc->sb_flags |= SB_NOUSER;
fc->global = true;
}
return ctx;
}
EXPORT_SYMBOL(init_pseudo);
int simple_open(struct inode *inode, struct file *file)
{
if (inode->i_private)
file->private_data = inode->i_private;
return 0;
}
EXPORT_SYMBOL(simple_open);
int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
struct inode *inode = d_inode(old_dentry);
dir->i_mtime = inode_set_ctime_to_ts(dir,
inode_set_ctime_current(inode));
inc_nlink(inode);
ihold(inode);
dget(dentry);
d_instantiate(dentry, inode);
return 0;
}
EXPORT_SYMBOL(simple_link);
int simple_empty(struct dentry *dentry)
{
struct dentry *child;
int ret = 0;
spin_lock(&dentry->d_lock);
list_for_each_entry(child, &dentry->d_subdirs, d_child) {
spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
if (simple_positive(child)) {
spin_unlock(&child->d_lock);
goto out;
}
spin_unlock(&child->d_lock);
}
ret = 1;
out:
spin_unlock(&dentry->d_lock);
return ret;
}
EXPORT_SYMBOL(simple_empty);
int simple_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
dir->i_mtime = inode_set_ctime_to_ts(dir,
inode_set_ctime_current(inode));
drop_nlink(inode);
dput(dentry);
return 0;
}
EXPORT_SYMBOL(simple_unlink);
int simple_rmdir(struct inode *dir, struct dentry *dentry)
{
if (!simple_empty(dentry))
return -ENOTEMPTY;
drop_nlink(d_inode(dentry));
simple_unlink(dir, dentry);
drop_nlink(dir);
return 0;
}
EXPORT_SYMBOL(simple_rmdir);
/**
* simple_rename_timestamp - update the various inode timestamps for rename
* @old_dir: old parent directory
* @old_dentry: dentry that is being renamed
* @new_dir: new parent directory
* @new_dentry: target for rename
*
* POSIX mandates that the old and new parent directories have their ctime and
* mtime updated, and that inodes of @old_dentry and @new_dentry (if any), have
* their ctime updated.
*/
void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
struct inode *newino = d_inode(new_dentry);
old_dir->i_mtime = inode_set_ctime_current(old_dir);
if (new_dir != old_dir)
new_dir->i_mtime = inode_set_ctime_current(new_dir);
inode_set_ctime_current(d_inode(old_dentry));
if (newino)
inode_set_ctime_current(newino);
}
EXPORT_SYMBOL_GPL(simple_rename_timestamp);
int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
bool old_is_dir = d_is_dir(old_dentry);
bool new_is_dir = d_is_dir(new_dentry);
if (old_dir != new_dir && old_is_dir != new_is_dir) {
if (old_is_dir) {
drop_nlink(old_dir);
inc_nlink(new_dir);
} else {
drop_nlink(new_dir);
inc_nlink(old_dir);
}
}
simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry);
return 0;
}
EXPORT_SYMBOL_GPL(simple_rename_exchange);
int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir,
struct dentry *old_dentry, struct inode *new_dir,
struct dentry *new_dentry, unsigned int flags)
{
int they_are_dirs = d_is_dir(old_dentry);
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;
if (flags & RENAME_EXCHANGE)
return simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry);
if (!simple_empty(new_dentry))
return -ENOTEMPTY;
if (d_really_is_positive(new_dentry)) {
simple_unlink(new_dir, new_dentry);
if (they_are_dirs) {
drop_nlink(d_inode(new_dentry));
drop_nlink(old_dir);
}
} else if (they_are_dirs) {
drop_nlink(old_dir);
inc_nlink(new_dir);
}
simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry);
return 0;
}
EXPORT_SYMBOL(simple_rename);
/**
* simple_setattr - setattr for simple filesystem
* @idmap: idmap of the target mount
* @dentry: dentry
* @iattr: iattr structure
*
* Returns 0 on success, -error on failure.
*
* simple_setattr is a simple ->setattr implementation without a proper
* implementation of size changes.
*
* It can either be used for in-memory filesystems or special files
* on simple regular filesystems. Anything that needs to change on-disk
* or wire state on size changes needs its own setattr method.
*/
int simple_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *iattr)
{
struct inode *inode = d_inode(dentry);
int error;
error = setattr_prepare(idmap, dentry, iattr);
if (error)
return error;
if (iattr->ia_valid & ATTR_SIZE)
truncate_setsize(inode, iattr->ia_size);
setattr_copy(idmap, inode, iattr);
mark_inode_dirty(inode);
return 0;
}
EXPORT_SYMBOL(simple_setattr);
static int simple_read_folio(struct file *file, struct folio *folio)
{
folio_zero_range(folio, 0, folio_size(folio));
flush_dcache_folio(folio);
folio_mark_uptodate(folio);
folio_unlock(folio);
return 0;
}
int simple_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len,
struct page **pagep, void **fsdata)
{
struct folio *folio;
folio = __filemap_get_folio(mapping, pos / PAGE_SIZE, FGP_WRITEBEGIN,
mapping_gfp_mask(mapping));
if (IS_ERR(folio))
return PTR_ERR(folio);
*pagep = &folio->page;
if (!folio_test_uptodate(folio) && (len != folio_size(folio))) {
size_t from = offset_in_folio(folio, pos);
folio_zero_segments(folio, 0, from,
from + len, folio_size(folio));
}
return 0;
}
EXPORT_SYMBOL(simple_write_begin);
/**
* simple_write_end - .write_end helper for non-block-device FSes
* @file: See .write_end of address_space_operations
* @mapping: "
* @pos: "
* @len: "
* @copied: "
* @page: "
* @fsdata: "
*
* simple_write_end does the minimum needed for updating a page after writing is
* done. It has the same API signature as the .write_end of
* address_space_operations vector. So it can just be set onto .write_end for
* FSes that don't need any other processing. i_mutex is assumed to be held.
* Block based filesystems should use generic_write_end().
* NOTE: Even though i_size might get updated by this function, mark_inode_dirty
* is not called, so a filesystem that actually does store data in .write_inode
* should extend on what's done here with a call to mark_inode_dirty() in the
* case that i_size has changed.
*
* Use *ONLY* with simple_read_folio()
*/
static int simple_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct folio *folio = page_folio(page);
struct inode *inode = folio->mapping->host;
loff_t last_pos = pos + copied;
/* zero the stale part of the folio if we did a short copy */
if (!folio_test_uptodate(folio)) {
if (copied < len) {
size_t from = offset_in_folio(folio, pos);
folio_zero_range(folio, from + copied, len - copied);
}
folio_mark_uptodate(folio);
}
/*
* No need to use i_size_read() here, the i_size
* cannot change under us because we hold the i_mutex.
*/
if (last_pos > inode->i_size)
i_size_write(inode, last_pos);
folio_mark_dirty(folio);
folio_unlock(folio);
folio_put(folio);
return copied;
}
/*
* Provides ramfs-style behavior: data in the pagecache, but no writeback.
*/
const struct address_space_operations ram_aops = {
.read_folio = simple_read_folio,
.write_begin = simple_write_begin,
.write_end = simple_write_end,
.dirty_folio = noop_dirty_folio,
};
EXPORT_SYMBOL(ram_aops);
/*
* the inodes created here are not hashed. If you use iunique to generate
* unique inode values later for this filesystem, then you must take care
* to pass it an appropriate max_reserved value to avoid collisions.
*/
int simple_fill_super(struct super_block *s, unsigned long magic,
const struct tree_descr *files)
{
struct inode *inode;
struct dentry *root;
struct dentry *dentry;
int i;
s->s_blocksize = PAGE_SIZE;
s->s_blocksize_bits = PAGE_SHIFT;
s->s_magic = magic;
s->s_op = &simple_super_operations;
s->s_time_gran = 1;
inode = new_inode(s);
if (!inode)
return -ENOMEM;
/*
* because the root inode is 1, the files array must not contain an
* entry at index 1
*/
inode->i_ino = 1;
inode->i_mode = S_IFDIR | 0755;
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
set_nlink(inode, 2);
root = d_make_root(inode);
if (!root)
return -ENOMEM;
for (i = 0; !files->name || files->name[0]; i++, files++) {
if (!files->name)
continue;
/* warn if it tries to conflict with the root inode */
if (unlikely(i == 1))
printk(KERN_WARNING "%s: %s passed in a files array"
"with an index of 1!\n", __func__,
s->s_type->name);
dentry = d_alloc_name(root, files->name);
if (!dentry)
goto out;
inode = new_inode(s);
if (!inode) {
dput(dentry);
goto out;
}
inode->i_mode = S_IFREG | files->mode;
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
inode->i_fop = files->ops;
inode->i_ino = i;
d_add(dentry, inode);
}
s->s_root = root;
return 0;
out:
d_genocide(root);
shrink_dcache_parent(root);
dput(root);
return -ENOMEM;
}
EXPORT_SYMBOL(simple_fill_super);
static DEFINE_SPINLOCK(pin_fs_lock);
int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
{
struct vfsmount *mnt = NULL;
spin_lock(&pin_fs_lock);
if (unlikely(!*mount)) {
spin_unlock(&pin_fs_lock);
mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
spin_lock(&pin_fs_lock);
if (!*mount)
*mount = mnt;
}
mntget(*mount);
++*count;
spin_unlock(&pin_fs_lock);
mntput(mnt);
return 0;
}
EXPORT_SYMBOL(simple_pin_fs);
void simple_release_fs(struct vfsmount **mount, int *count)
{
struct vfsmount *mnt;
spin_lock(&pin_fs_lock);
mnt = *mount;
if (!--*count)
*mount = NULL;
spin_unlock(&pin_fs_lock);
mntput(mnt);
}
EXPORT_SYMBOL(simple_release_fs);
/**
* simple_read_from_buffer - copy data from the buffer to user space
* @to: the user space buffer to read to
* @count: the maximum number of bytes to read
* @ppos: the current position in the buffer
* @from: the buffer to read from
* @available: the size of the buffer
*
* The simple_read_from_buffer() function reads up to @count bytes from the
* buffer @from at offset @ppos into the user space address starting at @to.
*
* On success, the number of bytes read is returned and the offset @ppos is
* advanced by this number, or negative value is returned on error.
**/
ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
const void *from, size_t available)
{
loff_t pos = *ppos;
size_t ret;
if (pos < 0)
return -EINVAL;
if (pos >= available || !count)
return 0;
if (count > available - pos)
count = available - pos;
ret = copy_to_user(to, from + pos, count);
if (ret == count)
return -EFAULT;
count -= ret;
*ppos = pos + count;
return count;
}
EXPORT_SYMBOL(simple_read_from_buffer);
/**
* simple_write_to_buffer - copy data from user space to the buffer
* @to: the buffer to write to
* @available: the size of the buffer
* @ppos: the current position in the buffer
* @from: the user space buffer to read from
* @count: the maximum number of bytes to read
*
* The simple_write_to_buffer() function reads up to @count bytes from the user
* space address starting at @from into the buffer @to at offset @ppos.
*
* On success, the number of bytes written is returned and the offset @ppos is
* advanced by this number, or negative value is returned on error.
**/
ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
const void __user *from, size_t count)
{
loff_t pos = *ppos;
size_t res;
if (pos < 0)
return -EINVAL;
if (pos >= available || !count)
return 0;
if (count > available - pos)
count = available - pos;
res = copy_from_user(to + pos, from, count);
if (res == count)
return -EFAULT;
count -= res;
*ppos = pos + count;
return count;
}
EXPORT_SYMBOL(simple_write_to_buffer);
/**
* memory_read_from_buffer - copy data from the buffer
* @to: the kernel space buffer to read to
* @count: the maximum number of bytes to read
* @ppos: the current position in the buffer
* @from: the buffer to read from
* @available: the size of the buffer
*
* The memory_read_from_buffer() function reads up to @count bytes from the
* buffer @from at offset @ppos into the kernel space address starting at @to.
*
* On success, the number of bytes read is returned and the offset @ppos is
* advanced by this number, or negative value is returned on error.
**/
ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
const void *from, size_t available)
{
loff_t pos = *ppos;
if (pos < 0)
return -EINVAL;
if (pos >= available)
return 0;
if (count > available - pos)
count = available - pos;
memcpy(to, from + pos, count);
*ppos = pos + count;
return count;
}
EXPORT_SYMBOL(memory_read_from_buffer);
/*
* Transaction based IO.
* The file expects a single write which triggers the transaction, and then
* possibly a read which collects the result - which is stored in a
* file-local buffer.
*/
void simple_transaction_set(struct file *file, size_t n)
{
struct simple_transaction_argresp *ar = file->private_data;
BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
/*
* The barrier ensures that ar->size will really remain zero until
* ar->data is ready for reading.
*/
smp_mb();
ar->size = n;
}
EXPORT_SYMBOL(simple_transaction_set);
char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
{
struct simple_transaction_argresp *ar;
static DEFINE_SPINLOCK(simple_transaction_lock);
if (size > SIMPLE_TRANSACTION_LIMIT - 1)
return ERR_PTR(-EFBIG);
ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
if (!ar)
return ERR_PTR(-ENOMEM);
spin_lock(&simple_transaction_lock);
/* only one write allowed per open */
if (file->private_data) {
spin_unlock(&simple_transaction_lock);
free_page((unsigned long)ar);
return ERR_PTR(-EBUSY);
}
file->private_data = ar;
spin_unlock(&simple_transaction_lock);
if (copy_from_user(ar->data, buf, size))
return ERR_PTR(-EFAULT);
return ar->data;
}
EXPORT_SYMBOL(simple_transaction_get);
ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
{
struct simple_transaction_argresp *ar = file->private_data;
if (!ar)
return 0;
return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
}
EXPORT_SYMBOL(simple_transaction_read);
int simple_transaction_release(struct inode *inode, struct file *file)
{
free_page((unsigned long)file->private_data);
return 0;
}
EXPORT_SYMBOL(simple_transaction_release);
/* Simple attribute files */
struct simple_attr {
int (*get)(void *, u64 *);
int (*set)(void *, u64);
char get_buf[24]; /* enough to store a u64 and "\n\0" */
char set_buf[24];
void *data;
const char *fmt; /* format for read operation */
struct mutex mutex; /* protects access to these buffers */
};
/* simple_attr_open is called by an actual attribute open file operation
* to set the attribute specific access operations. */
int simple_attr_open(struct inode *inode, struct file *file,
int (*get)(void *, u64 *), int (*set)(void *, u64),
const char *fmt)
{
struct simple_attr *attr;
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (!attr)
return -ENOMEM;
attr->get = get;
attr->set = set;
attr->data = inode->i_private;
attr->fmt = fmt;
mutex_init(&attr->mutex);
file->private_data = attr;
return nonseekable_open(inode, file);
}
EXPORT_SYMBOL_GPL(simple_attr_open);
int simple_attr_release(struct inode *inode, struct file *file)
{
kfree(file->private_data);
return 0;
}
EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
/* read from the buffer that is filled with the get function */
ssize_t simple_attr_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
struct simple_attr *attr;
size_t size;
ssize_t ret;
attr = file->private_data;
if (!attr->get)
return -EACCES;
ret = mutex_lock_interruptible(&attr->mutex);
if (ret)
return ret;
if (*ppos && attr->get_buf[0]) {
/* continued read */
size = strlen(attr->get_buf);
} else {
/* first read */
u64 val;
ret = attr->get(attr->data, &val);
if (ret)
goto out;
size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
attr->fmt, (unsigned long long)val);
}
ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
out:
mutex_unlock(&attr->mutex);
return ret;
}
EXPORT_SYMBOL_GPL(simple_attr_read);
/* interpret the buffer as a number to call the set function with */
static ssize_t simple_attr_write_xsigned(struct file *file, const char __user *buf,
size_t len, loff_t *ppos, bool is_signed)
{
struct simple_attr *attr;
unsigned long long val;
size_t size;
ssize_t ret;
attr = file->private_data;
if (!attr->set)
return -EACCES;
ret = mutex_lock_interruptible(&attr->mutex);
if (ret)
return ret;
ret = -EFAULT;
size = min(sizeof(attr->set_buf) - 1, len);
if (copy_from_user(attr->set_buf, buf, size))
goto out;
attr->set_buf[size] = '\0';
if (is_signed)
ret = kstrtoll(attr->set_buf, 0, &val);
else
ret = kstrtoull(attr->set_buf, 0, &val);
if (ret)
goto out;
ret = attr->set(attr->data, val);
if (ret == 0)
ret = len; /* on success, claim we got the whole input */
out:
mutex_unlock(&attr->mutex);
return ret;
}
ssize_t simple_attr_write(struct file *file, const char __user *buf,
size_t len, loff_t *ppos)
{
return simple_attr_write_xsigned(file, buf, len, ppos, false);
}
EXPORT_SYMBOL_GPL(simple_attr_write);
ssize_t simple_attr_write_signed(struct file *file, const char __user *buf,
size_t len, loff_t *ppos)
{
return simple_attr_write_xsigned(file, buf, len, ppos, true);
}
EXPORT_SYMBOL_GPL(simple_attr_write_signed);
/**
* generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
* @sb: filesystem to do the file handle conversion on
* @fid: file handle to convert
* @fh_len: length of the file handle in bytes
* @fh_type: type of file handle
* @get_inode: filesystem callback to retrieve inode
*
* This function decodes @fid as long as it has one of the well-known
* Linux filehandle types and calls @get_inode on it to retrieve the
* inode for the object specified in the file handle.
*/
struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type, struct inode *(*get_inode)
(struct super_block *sb, u64 ino, u32 gen))
{
struct inode *inode = NULL;
if (fh_len < 2)
return NULL;
switch (fh_type) {
case FILEID_INO32_GEN:
case FILEID_INO32_GEN_PARENT:
inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
break;
}
return d_obtain_alias(inode);
}
EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
/**
* generic_fh_to_parent - generic helper for the fh_to_parent export operation
* @sb: filesystem to do the file handle conversion on
* @fid: file handle to convert
* @fh_len: length of the file handle in bytes
* @fh_type: type of file handle
* @get_inode: filesystem callback to retrieve inode
*
* This function decodes @fid as long as it has one of the well-known
* Linux filehandle types and calls @get_inode on it to retrieve the
* inode for the _parent_ object specified in the file handle if it
* is specified in the file handle, or NULL otherwise.
*/
struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type, struct inode *(*get_inode)
(struct super_block *sb, u64 ino, u32 gen))
{
struct inode *inode = NULL;
if (fh_len <= 2)
return NULL;
switch (fh_type) {
case FILEID_INO32_GEN_PARENT:
inode = get_inode(sb, fid->i32.parent_ino,
(fh_len > 3 ? fid->i32.parent_gen : 0));
break;
}
return d_obtain_alias(inode);
}
EXPORT_SYMBOL_GPL(generic_fh_to_parent);
/**
* __generic_file_fsync - generic fsync implementation for simple filesystems
*
* @file: file to synchronize
* @start: start offset in bytes
* @end: end offset in bytes (inclusive)
* @datasync: only synchronize essential metadata if true
*
* This is a generic implementation of the fsync method for simple
* filesystems which track all non-inode metadata in the buffers list
* hanging off the address_space structure.
*/
int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
int datasync)
{
struct inode *inode = file->f_mapping->host;
int err;
int ret;
err = file_write_and_wait_range(file, start, end);
if (err)
return err;
inode_lock(inode);
ret = sync_mapping_buffers(inode->i_mapping);
if (!(inode->i_state & I_DIRTY_ALL))
goto out;
if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
goto out;
err = sync_inode_metadata(inode, 1);
if (ret == 0)
ret = err;
out:
inode_unlock(inode);
/* check and advance again to catch errors after syncing out buffers */
err = file_check_and_advance_wb_err(file);
if (ret == 0)
ret = err;
return ret;
}
EXPORT_SYMBOL(__generic_file_fsync);
/**
* generic_file_fsync - generic fsync implementation for simple filesystems
* with flush
* @file: file to synchronize
* @start: start offset in bytes
* @end: end offset in bytes (inclusive)
* @datasync: only synchronize essential metadata if true
*
*/
int generic_file_fsync(struct file *file, loff_t start, loff_t end,
int datasync)
{
struct inode *inode = file->f_mapping->host;
int err;
err = __generic_file_fsync(file, start, end, datasync);
if (err)
return err;
return blkdev_issue_flush(inode->i_sb->s_bdev);
}
EXPORT_SYMBOL(generic_file_fsync);
/**
* generic_check_addressable - Check addressability of file system
* @blocksize_bits: log of file system block size
* @num_blocks: number of blocks in file system
*
* Determine whether a file system with @num_blocks blocks (and a
* block size of 2**@blocksize_bits) is addressable by the sector_t
* and page cache of the system. Return 0 if so and -EFBIG otherwise.
*/
int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
{
u64 last_fs_block = num_blocks - 1;
u64 last_fs_page =
last_fs_block >> (PAGE_SHIFT - blocksize_bits);
if (unlikely(num_blocks == 0))
return 0;
if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
return -EINVAL;
if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
(last_fs_page > (pgoff_t)(~0ULL))) {
return -EFBIG;
}
return 0;
}
EXPORT_SYMBOL(generic_check_addressable);
/*
* No-op implementation of ->fsync for in-memory filesystems.
*/
int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
return 0;
}
EXPORT_SYMBOL(noop_fsync);
ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
/*
* iomap based filesystems support direct I/O without need for
* this callback. However, it still needs to be set in
* inode->a_ops so that open/fcntl know that direct I/O is
* generally supported.
*/
return -EINVAL;
}
EXPORT_SYMBOL_GPL(noop_direct_IO);
/* Because kfree isn't assignment-compatible with void(void*) ;-/ */
void kfree_link(void *p)
{
kfree(p);
}
EXPORT_SYMBOL(kfree_link);
struct inode *alloc_anon_inode(struct super_block *s)
{
static const struct address_space_operations anon_aops = {
.dirty_folio = noop_dirty_folio,
};
struct inode *inode = new_inode_pseudo(s);
if (!inode)
return ERR_PTR(-ENOMEM);
inode->i_ino = get_next_ino();
inode->i_mapping->a_ops = &anon_aops;
/*
* Mark the inode dirty from the very beginning,
* that way it will never be moved to the dirty
* list because mark_inode_dirty() will think
* that it already _is_ on the dirty list.
*/
inode->i_state = I_DIRTY;
inode->i_mode = S_IRUSR | S_IWUSR;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
inode->i_flags |= S_PRIVATE;
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
return inode;
}
EXPORT_SYMBOL(alloc_anon_inode);
/**
* simple_nosetlease - generic helper for prohibiting leases
* @filp: file pointer
* @arg: type of lease to obtain
* @flp: new lease supplied for insertion
* @priv: private data for lm_setup operation
*
* Generic helper for filesystems that do not wish to allow leases to be set.
* All arguments are ignored and it just returns -EINVAL.
*/
int
simple_nosetlease(struct file *filp, int arg, struct file_lock **flp,
void **priv)
{
return -EINVAL;
}
EXPORT_SYMBOL(simple_nosetlease);
/**
* simple_get_link - generic helper to get the target of "fast" symlinks
* @dentry: not used here
* @inode: the symlink inode
* @done: not used here
*
* Generic helper for filesystems to use for symlink inodes where a pointer to
* the symlink target is stored in ->i_link. NOTE: this isn't normally called,
* since as an optimization the path lookup code uses any non-NULL ->i_link
* directly, without calling ->get_link(). But ->get_link() still must be set,
* to mark the inode_operations as being for a symlink.
*
* Return: the symlink target
*/
const char *simple_get_link(struct dentry *dentry, struct inode *inode,
struct delayed_call *done)
{
return inode->i_link;
}
EXPORT_SYMBOL(simple_get_link);
const struct inode_operations simple_symlink_inode_operations = {
.get_link = simple_get_link,
};
EXPORT_SYMBOL(simple_symlink_inode_operations);
/*
* Operations for a permanently empty directory.
*/
static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
return ERR_PTR(-ENOENT);
}
static int empty_dir_getattr(struct mnt_idmap *idmap,
const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
struct inode *inode = d_inode(path->dentry);
generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
return 0;
}
static int empty_dir_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr)
{
return -EPERM;
}
static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
{
return -EOPNOTSUPP;
}
static const struct inode_operations empty_dir_inode_operations = {
.lookup = empty_dir_lookup,
.permission = generic_permission,
.setattr = empty_dir_setattr,
.getattr = empty_dir_getattr,
.listxattr = empty_dir_listxattr,
};
static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
{
/* An empty directory has two entries . and .. at offsets 0 and 1 */
return generic_file_llseek_size(file, offset, whence, 2, 2);
}
static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
{
dir_emit_dots(file, ctx);
return 0;
}
static const struct file_operations empty_dir_operations = {
.llseek = empty_dir_llseek,
.read = generic_read_dir,
.iterate_shared = empty_dir_readdir,
.fsync = noop_fsync,
};
void make_empty_dir_inode(struct inode *inode)
{
set_nlink(inode, 2);
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
inode->i_uid = GLOBAL_ROOT_UID;
inode->i_gid = GLOBAL_ROOT_GID;
inode->i_rdev = 0;
inode->i_size = 0;
inode->i_blkbits = PAGE_SHIFT;
inode->i_blocks = 0;
inode->i_op = &empty_dir_inode_operations;
inode->i_opflags &= ~IOP_XATTR;
inode->i_fop = &empty_dir_operations;
}
bool is_empty_dir_inode(struct inode *inode)
{
return (inode->i_fop == &empty_dir_operations) &&
(inode->i_op == &empty_dir_inode_operations);
}
#if IS_ENABLED(CONFIG_UNICODE)
/**
* generic_ci_d_compare - generic d_compare implementation for casefolding filesystems
* @dentry: dentry whose name we are checking against
* @len: len of name of dentry
* @str: str pointer to name of dentry
* @name: Name to compare against
*
* Return: 0 if names match, 1 if mismatch, or -ERRNO
*/
static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
const char *str, const struct qstr *name)
{
const struct dentry *parent = READ_ONCE(dentry->d_parent);
const struct inode *dir = READ_ONCE(parent->d_inode);
const struct super_block *sb = dentry->d_sb;
const struct unicode_map *um = sb->s_encoding;
struct qstr qstr = QSTR_INIT(str, len);
char strbuf[DNAME_INLINE_LEN];
int ret;
if (!dir || !IS_CASEFOLDED(dir))
goto fallback;
/*
* If the dentry name is stored in-line, then it may be concurrently
* modified by a rename. If this happens, the VFS will eventually retry
* the lookup, so it doesn't matter what ->d_compare() returns.
* However, it's unsafe to call utf8_strncasecmp() with an unstable
* string. Therefore, we have to copy the name into a temporary buffer.
*/
if (len <= DNAME_INLINE_LEN - 1) {
memcpy(strbuf, str, len);
strbuf[len] = 0;
qstr.name = strbuf;
/* prevent compiler from optimizing out the temporary buffer */
barrier();
}
ret = utf8_strncasecmp(um, name, &qstr);
if (ret >= 0)
return ret;
if (sb_has_strict_encoding(sb))
return -EINVAL;
fallback:
if (len != name->len)
return 1;
return !!memcmp(str, name->name, len);
}
/**
* generic_ci_d_hash - generic d_hash implementation for casefolding filesystems
* @dentry: dentry of the parent directory
* @str: qstr of name whose hash we should fill in
*
* Return: 0 if hash was successful or unchanged, and -EINVAL on error
*/
static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str)
{
const struct inode *dir = READ_ONCE(dentry->d_inode);
struct super_block *sb = dentry->d_sb;
const struct unicode_map *um = sb->s_encoding;
int ret = 0;
if (!dir || !IS_CASEFOLDED(dir))
return 0;
ret = utf8_casefold_hash(um, dentry, str);
if (ret < 0 && sb_has_strict_encoding(sb))
return -EINVAL;
return 0;
}
static const struct dentry_operations generic_ci_dentry_ops = {
.d_hash = generic_ci_d_hash,
.d_compare = generic_ci_d_compare,
};
#endif
#ifdef CONFIG_FS_ENCRYPTION
static const struct dentry_operations generic_encrypted_dentry_ops = {
.d_revalidate = fscrypt_d_revalidate,
};
#endif
#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE)
static const struct dentry_operations generic_encrypted_ci_dentry_ops = {
.d_hash = generic_ci_d_hash,
.d_compare = generic_ci_d_compare,
.d_revalidate = fscrypt_d_revalidate,
};
#endif
/**
* generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry
* @dentry: dentry to set ops on
*
* Casefolded directories need d_hash and d_compare set, so that the dentries
* contained in them are handled case-insensitively. Note that these operations
* are needed on the parent directory rather than on the dentries in it, and
* while the casefolding flag can be toggled on and off on an empty directory,
* dentry_operations can't be changed later. As a result, if the filesystem has
* casefolding support enabled at all, we have to give all dentries the
* casefolding operations even if their inode doesn't have the casefolding flag
* currently (and thus the casefolding ops would be no-ops for now).
*
* Encryption works differently in that the only dentry operation it needs is
* d_revalidate, which it only needs on dentries that have the no-key name flag.
* The no-key flag can't be set "later", so we don't have to worry about that.
*
* Finally, to maximize compatibility with overlayfs (which isn't compatible
* with certain dentry operations) and to avoid taking an unnecessary
* performance hit, we use custom dentry_operations for each possible
* combination rather than always installing all operations.
*/
void generic_set_encrypted_ci_d_ops(struct dentry *dentry)
{
#ifdef CONFIG_FS_ENCRYPTION
bool needs_encrypt_ops = dentry->d_flags & DCACHE_NOKEY_NAME;
#endif
#if IS_ENABLED(CONFIG_UNICODE)
bool needs_ci_ops = dentry->d_sb->s_encoding;
#endif
#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE)
if (needs_encrypt_ops && needs_ci_ops) {
d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops);
return;
}
#endif
#ifdef CONFIG_FS_ENCRYPTION
if (needs_encrypt_ops) {
d_set_d_op(dentry, &generic_encrypted_dentry_ops);
return;
}
#endif
#if IS_ENABLED(CONFIG_UNICODE)
if (needs_ci_ops) {
d_set_d_op(dentry, &generic_ci_dentry_ops);
return;
}
#endif
}
EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops);
/**
* inode_maybe_inc_iversion - increments i_version
* @inode: inode with the i_version that should be updated
* @force: increment the counter even if it's not necessary?
*
* Every time the inode is modified, the i_version field must be seen to have
* changed by any observer.
*
* If "force" is set or the QUERIED flag is set, then ensure that we increment
* the value, and clear the queried flag.
*
* In the common case where neither is set, then we can return "false" without
* updating i_version.
*
* If this function returns false, and no other metadata has changed, then we
* can avoid logging the metadata.
*/
bool inode_maybe_inc_iversion(struct inode *inode, bool force)
{
u64 cur, new;
/*
* The i_version field is not strictly ordered with any other inode
* information, but the legacy inode_inc_iversion code used a spinlock
* to serialize increments.
*
* Here, we add full memory barriers to ensure that any de-facto
* ordering with other info is preserved.
*
* This barrier pairs with the barrier in inode_query_iversion()
*/
smp_mb();
cur = inode_peek_iversion_raw(inode);
do {
/* If flag is clear then we needn't do anything */
if (!force && !(cur & I_VERSION_QUERIED))
return false;
/* Since lowest bit is flag, add 2 to avoid it */
new = (cur & ~I_VERSION_QUERIED) + I_VERSION_INCREMENT;
} while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new));
return true;
}
EXPORT_SYMBOL(inode_maybe_inc_iversion);
/**
* inode_query_iversion - read i_version for later use
* @inode: inode from which i_version should be read
*
* Read the inode i_version counter. This should be used by callers that wish
* to store the returned i_version for later comparison. This will guarantee
* that a later query of the i_version will result in a different value if
* anything has changed.
*
* In this implementation, we fetch the current value, set the QUERIED flag and
* then try to swap it into place with a cmpxchg, if it wasn't already set. If
* that fails, we try again with the newly fetched value from the cmpxchg.
*/
u64 inode_query_iversion(struct inode *inode)
{
u64 cur, new;
cur = inode_peek_iversion_raw(inode);
do {
/* If flag is already set, then no need to swap */
if (cur & I_VERSION_QUERIED) {
/*
* This barrier (and the implicit barrier in the
* cmpxchg below) pairs with the barrier in
* inode_maybe_inc_iversion().
*/
smp_mb();
break;
}
new = cur | I_VERSION_QUERIED;
} while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new));
return cur >> I_VERSION_QUERIED_SHIFT;
}
EXPORT_SYMBOL(inode_query_iversion);
ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter,
ssize_t direct_written, ssize_t buffered_written)
{
struct address_space *mapping = iocb->ki_filp->f_mapping;
loff_t pos = iocb->ki_pos - buffered_written;
loff_t end = iocb->ki_pos - 1;
int err;
/*
* If the buffered write fallback returned an error, we want to return
* the number of bytes which were written by direct I/O, or the error
* code if that was zero.
*
* Note that this differs from normal direct-io semantics, which will
* return -EFOO even if some bytes were written.
*/
if (unlikely(buffered_written < 0)) {
if (direct_written)
return direct_written;
return buffered_written;
}
/*
* We need to ensure that the page cache pages are written to disk and
* invalidated to preserve the expected O_DIRECT semantics.
*/
err = filemap_write_and_wait_range(mapping, pos, end);
if (err < 0) {
/*
* We don't know how much we wrote, so just return the number of
* bytes which were direct-written
*/
if (direct_written)
return direct_written;
return err;
}
invalidate_mapping_pages(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
return direct_written + buffered_written;
}
EXPORT_SYMBOL_GPL(direct_write_fallback);
| linux-master | fs/libfs.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/pnode.c
*
* (C) Copyright IBM Corporation 2005.
* Author : Ram Pai ([email protected])
*/
#include <linux/mnt_namespace.h>
#include <linux/mount.h>
#include <linux/fs.h>
#include <linux/nsproxy.h>
#include <uapi/linux/mount.h>
#include "internal.h"
#include "pnode.h"
/* return the next shared peer mount of @p */
static inline struct mount *next_peer(struct mount *p)
{
return list_entry(p->mnt_share.next, struct mount, mnt_share);
}
static inline struct mount *first_slave(struct mount *p)
{
return list_entry(p->mnt_slave_list.next, struct mount, mnt_slave);
}
static inline struct mount *last_slave(struct mount *p)
{
return list_entry(p->mnt_slave_list.prev, struct mount, mnt_slave);
}
static inline struct mount *next_slave(struct mount *p)
{
return list_entry(p->mnt_slave.next, struct mount, mnt_slave);
}
static struct mount *get_peer_under_root(struct mount *mnt,
struct mnt_namespace *ns,
const struct path *root)
{
struct mount *m = mnt;
do {
/* Check the namespace first for optimization */
if (m->mnt_ns == ns && is_path_reachable(m, m->mnt.mnt_root, root))
return m;
m = next_peer(m);
} while (m != mnt);
return NULL;
}
/*
* Get ID of closest dominating peer group having a representative
* under the given root.
*
* Caller must hold namespace_sem
*/
int get_dominating_id(struct mount *mnt, const struct path *root)
{
struct mount *m;
for (m = mnt->mnt_master; m != NULL; m = m->mnt_master) {
struct mount *d = get_peer_under_root(m, mnt->mnt_ns, root);
if (d)
return d->mnt_group_id;
}
return 0;
}
static int do_make_slave(struct mount *mnt)
{
struct mount *master, *slave_mnt;
if (list_empty(&mnt->mnt_share)) {
if (IS_MNT_SHARED(mnt)) {
mnt_release_group_id(mnt);
CLEAR_MNT_SHARED(mnt);
}
master = mnt->mnt_master;
if (!master) {
struct list_head *p = &mnt->mnt_slave_list;
while (!list_empty(p)) {
slave_mnt = list_first_entry(p,
struct mount, mnt_slave);
list_del_init(&slave_mnt->mnt_slave);
slave_mnt->mnt_master = NULL;
}
return 0;
}
} else {
struct mount *m;
/*
* slave 'mnt' to a peer mount that has the
* same root dentry. If none is available then
* slave it to anything that is available.
*/
for (m = master = next_peer(mnt); m != mnt; m = next_peer(m)) {
if (m->mnt.mnt_root == mnt->mnt.mnt_root) {
master = m;
break;
}
}
list_del_init(&mnt->mnt_share);
mnt->mnt_group_id = 0;
CLEAR_MNT_SHARED(mnt);
}
list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
slave_mnt->mnt_master = master;
list_move(&mnt->mnt_slave, &master->mnt_slave_list);
list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
INIT_LIST_HEAD(&mnt->mnt_slave_list);
mnt->mnt_master = master;
return 0;
}
/*
* vfsmount lock must be held for write
*/
void change_mnt_propagation(struct mount *mnt, int type)
{
if (type == MS_SHARED) {
set_mnt_shared(mnt);
return;
}
do_make_slave(mnt);
if (type != MS_SLAVE) {
list_del_init(&mnt->mnt_slave);
mnt->mnt_master = NULL;
if (type == MS_UNBINDABLE)
mnt->mnt.mnt_flags |= MNT_UNBINDABLE;
else
mnt->mnt.mnt_flags &= ~MNT_UNBINDABLE;
}
}
/*
* get the next mount in the propagation tree.
* @m: the mount seen last
* @origin: the original mount from where the tree walk initiated
*
* Note that peer groups form contiguous segments of slave lists.
* We rely on that in get_source() to be able to find out if
* vfsmount found while iterating with propagation_next() is
* a peer of one we'd found earlier.
*/
static struct mount *propagation_next(struct mount *m,
struct mount *origin)
{
/* are there any slaves of this mount? */
if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
return first_slave(m);
while (1) {
struct mount *master = m->mnt_master;
if (master == origin->mnt_master) {
struct mount *next = next_peer(m);
return (next == origin) ? NULL : next;
} else if (m->mnt_slave.next != &master->mnt_slave_list)
return next_slave(m);
/* back at master */
m = master;
}
}
static struct mount *skip_propagation_subtree(struct mount *m,
struct mount *origin)
{
/*
* Advance m such that propagation_next will not return
* the slaves of m.
*/
if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
m = last_slave(m);
return m;
}
static struct mount *next_group(struct mount *m, struct mount *origin)
{
while (1) {
while (1) {
struct mount *next;
if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
return first_slave(m);
next = next_peer(m);
if (m->mnt_group_id == origin->mnt_group_id) {
if (next == origin)
return NULL;
} else if (m->mnt_slave.next != &next->mnt_slave)
break;
m = next;
}
/* m is the last peer */
while (1) {
struct mount *master = m->mnt_master;
if (m->mnt_slave.next != &master->mnt_slave_list)
return next_slave(m);
m = next_peer(master);
if (master->mnt_group_id == origin->mnt_group_id)
break;
if (master->mnt_slave.next == &m->mnt_slave)
break;
m = master;
}
if (m == origin)
return NULL;
}
}
/* all accesses are serialized by namespace_sem */
static struct mount *last_dest, *first_source, *last_source, *dest_master;
static struct hlist_head *list;
static inline bool peers(const struct mount *m1, const struct mount *m2)
{
return m1->mnt_group_id == m2->mnt_group_id && m1->mnt_group_id;
}
static int propagate_one(struct mount *m, struct mountpoint *dest_mp)
{
struct mount *child;
int type;
/* skip ones added by this propagate_mnt() */
if (IS_MNT_NEW(m))
return 0;
/* skip if mountpoint isn't covered by it */
if (!is_subdir(dest_mp->m_dentry, m->mnt.mnt_root))
return 0;
if (peers(m, last_dest)) {
type = CL_MAKE_SHARED;
} else {
struct mount *n, *p;
bool done;
for (n = m; ; n = p) {
p = n->mnt_master;
if (p == dest_master || IS_MNT_MARKED(p))
break;
}
do {
struct mount *parent = last_source->mnt_parent;
if (peers(last_source, first_source))
break;
done = parent->mnt_master == p;
if (done && peers(n, parent))
break;
last_source = last_source->mnt_master;
} while (!done);
type = CL_SLAVE;
/* beginning of peer group among the slaves? */
if (IS_MNT_SHARED(m))
type |= CL_MAKE_SHARED;
}
child = copy_tree(last_source, last_source->mnt.mnt_root, type);
if (IS_ERR(child))
return PTR_ERR(child);
read_seqlock_excl(&mount_lock);
mnt_set_mountpoint(m, dest_mp, child);
if (m->mnt_master != dest_master)
SET_MNT_MARK(m->mnt_master);
read_sequnlock_excl(&mount_lock);
last_dest = m;
last_source = child;
hlist_add_head(&child->mnt_hash, list);
return count_mounts(m->mnt_ns, child);
}
/*
* mount 'source_mnt' under the destination 'dest_mnt' at
* dentry 'dest_dentry'. And propagate that mount to
* all the peer and slave mounts of 'dest_mnt'.
* Link all the new mounts into a propagation tree headed at
* source_mnt. Also link all the new mounts using ->mnt_list
* headed at source_mnt's ->mnt_list
*
* @dest_mnt: destination mount.
* @dest_dentry: destination dentry.
* @source_mnt: source mount.
* @tree_list : list of heads of trees to be attached.
*/
int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
struct mount *source_mnt, struct hlist_head *tree_list)
{
struct mount *m, *n;
int ret = 0;
/*
* we don't want to bother passing tons of arguments to
* propagate_one(); everything is serialized by namespace_sem,
* so globals will do just fine.
*/
last_dest = dest_mnt;
first_source = source_mnt;
last_source = source_mnt;
list = tree_list;
dest_master = dest_mnt->mnt_master;
/* all peers of dest_mnt, except dest_mnt itself */
for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) {
ret = propagate_one(n, dest_mp);
if (ret)
goto out;
}
/* all slave groups */
for (m = next_group(dest_mnt, dest_mnt); m;
m = next_group(m, dest_mnt)) {
/* everything in that slave group */
n = m;
do {
ret = propagate_one(n, dest_mp);
if (ret)
goto out;
n = next_peer(n);
} while (n != m);
}
out:
read_seqlock_excl(&mount_lock);
hlist_for_each_entry(n, tree_list, mnt_hash) {
m = n->mnt_parent;
if (m->mnt_master != dest_mnt->mnt_master)
CLEAR_MNT_MARK(m->mnt_master);
}
read_sequnlock_excl(&mount_lock);
return ret;
}
static struct mount *find_topper(struct mount *mnt)
{
/* If there is exactly one mount covering mnt completely return it. */
struct mount *child;
if (!list_is_singular(&mnt->mnt_mounts))
return NULL;
child = list_first_entry(&mnt->mnt_mounts, struct mount, mnt_child);
if (child->mnt_mountpoint != mnt->mnt.mnt_root)
return NULL;
return child;
}
/*
* return true if the refcount is greater than count
*/
static inline int do_refcount_check(struct mount *mnt, int count)
{
return mnt_get_count(mnt) > count;
}
/**
* propagation_would_overmount - check whether propagation from @from
* would overmount @to
* @from: shared mount
* @to: mount to check
* @mp: future mountpoint of @to on @from
*
* If @from propagates mounts to @to, @from and @to must either be peers
* or one of the masters in the hierarchy of masters of @to must be a
* peer of @from.
*
* If the root of the @to mount is equal to the future mountpoint @mp of
* the @to mount on @from then @to will be overmounted by whatever is
* propagated to it.
*
* Context: This function expects namespace_lock() to be held and that
* @mp is stable.
* Return: If @from overmounts @to, true is returned, false if not.
*/
bool propagation_would_overmount(const struct mount *from,
const struct mount *to,
const struct mountpoint *mp)
{
if (!IS_MNT_SHARED(from))
return false;
if (IS_MNT_NEW(to))
return false;
if (to->mnt.mnt_root != mp->m_dentry)
return false;
for (const struct mount *m = to; m; m = m->mnt_master) {
if (peers(from, m))
return true;
}
return false;
}
/*
* check if the mount 'mnt' can be unmounted successfully.
* @mnt: the mount to be checked for unmount
* NOTE: unmounting 'mnt' would naturally propagate to all
* other mounts its parent propagates to.
* Check if any of these mounts that **do not have submounts**
* have more references than 'refcnt'. If so return busy.
*
* vfsmount lock must be held for write
*/
int propagate_mount_busy(struct mount *mnt, int refcnt)
{
struct mount *m, *child, *topper;
struct mount *parent = mnt->mnt_parent;
if (mnt == parent)
return do_refcount_check(mnt, refcnt);
/*
* quickly check if the current mount can be unmounted.
* If not, we don't have to go checking for all other
* mounts
*/
if (!list_empty(&mnt->mnt_mounts) || do_refcount_check(mnt, refcnt))
return 1;
for (m = propagation_next(parent, parent); m;
m = propagation_next(m, parent)) {
int count = 1;
child = __lookup_mnt(&m->mnt, mnt->mnt_mountpoint);
if (!child)
continue;
/* Is there exactly one mount on the child that covers
* it completely whose reference should be ignored?
*/
topper = find_topper(child);
if (topper)
count += 1;
else if (!list_empty(&child->mnt_mounts))
continue;
if (do_refcount_check(child, count))
return 1;
}
return 0;
}
/*
* Clear MNT_LOCKED when it can be shown to be safe.
*
* mount_lock lock must be held for write
*/
void propagate_mount_unlock(struct mount *mnt)
{
struct mount *parent = mnt->mnt_parent;
struct mount *m, *child;
BUG_ON(parent == mnt);
for (m = propagation_next(parent, parent); m;
m = propagation_next(m, parent)) {
child = __lookup_mnt(&m->mnt, mnt->mnt_mountpoint);
if (child)
child->mnt.mnt_flags &= ~MNT_LOCKED;
}
}
static void umount_one(struct mount *mnt, struct list_head *to_umount)
{
CLEAR_MNT_MARK(mnt);
mnt->mnt.mnt_flags |= MNT_UMOUNT;
list_del_init(&mnt->mnt_child);
list_del_init(&mnt->mnt_umounting);
list_move_tail(&mnt->mnt_list, to_umount);
}
/*
* NOTE: unmounting 'mnt' naturally propagates to all other mounts its
* parent propagates to.
*/
static bool __propagate_umount(struct mount *mnt,
struct list_head *to_umount,
struct list_head *to_restore)
{
bool progress = false;
struct mount *child;
/*
* The state of the parent won't change if this mount is
* already unmounted or marked as without children.
*/
if (mnt->mnt.mnt_flags & (MNT_UMOUNT | MNT_MARKED))
goto out;
/* Verify topper is the only grandchild that has not been
* speculatively unmounted.
*/
list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
if (child->mnt_mountpoint == mnt->mnt.mnt_root)
continue;
if (!list_empty(&child->mnt_umounting) && IS_MNT_MARKED(child))
continue;
/* Found a mounted child */
goto children;
}
/* Mark mounts that can be unmounted if not locked */
SET_MNT_MARK(mnt);
progress = true;
/* If a mount is without children and not locked umount it. */
if (!IS_MNT_LOCKED(mnt)) {
umount_one(mnt, to_umount);
} else {
children:
list_move_tail(&mnt->mnt_umounting, to_restore);
}
out:
return progress;
}
static void umount_list(struct list_head *to_umount,
struct list_head *to_restore)
{
struct mount *mnt, *child, *tmp;
list_for_each_entry(mnt, to_umount, mnt_list) {
list_for_each_entry_safe(child, tmp, &mnt->mnt_mounts, mnt_child) {
/* topper? */
if (child->mnt_mountpoint == mnt->mnt.mnt_root)
list_move_tail(&child->mnt_umounting, to_restore);
else
umount_one(child, to_umount);
}
}
}
static void restore_mounts(struct list_head *to_restore)
{
/* Restore mounts to a clean working state */
while (!list_empty(to_restore)) {
struct mount *mnt, *parent;
struct mountpoint *mp;
mnt = list_first_entry(to_restore, struct mount, mnt_umounting);
CLEAR_MNT_MARK(mnt);
list_del_init(&mnt->mnt_umounting);
/* Should this mount be reparented? */
mp = mnt->mnt_mp;
parent = mnt->mnt_parent;
while (parent->mnt.mnt_flags & MNT_UMOUNT) {
mp = parent->mnt_mp;
parent = parent->mnt_parent;
}
if (parent != mnt->mnt_parent)
mnt_change_mountpoint(parent, mp, mnt);
}
}
static void cleanup_umount_visitations(struct list_head *visited)
{
while (!list_empty(visited)) {
struct mount *mnt =
list_first_entry(visited, struct mount, mnt_umounting);
list_del_init(&mnt->mnt_umounting);
}
}
/*
* collect all mounts that receive propagation from the mount in @list,
* and return these additional mounts in the same list.
* @list: the list of mounts to be unmounted.
*
* vfsmount lock must be held for write
*/
int propagate_umount(struct list_head *list)
{
struct mount *mnt;
LIST_HEAD(to_restore);
LIST_HEAD(to_umount);
LIST_HEAD(visited);
/* Find candidates for unmounting */
list_for_each_entry_reverse(mnt, list, mnt_list) {
struct mount *parent = mnt->mnt_parent;
struct mount *m;
/*
* If this mount has already been visited it is known that it's
* entire peer group and all of their slaves in the propagation
* tree for the mountpoint has already been visited and there is
* no need to visit them again.
*/
if (!list_empty(&mnt->mnt_umounting))
continue;
list_add_tail(&mnt->mnt_umounting, &visited);
for (m = propagation_next(parent, parent); m;
m = propagation_next(m, parent)) {
struct mount *child = __lookup_mnt(&m->mnt,
mnt->mnt_mountpoint);
if (!child)
continue;
if (!list_empty(&child->mnt_umounting)) {
/*
* If the child has already been visited it is
* know that it's entire peer group and all of
* their slaves in the propgation tree for the
* mountpoint has already been visited and there
* is no need to visit this subtree again.
*/
m = skip_propagation_subtree(m, parent);
continue;
} else if (child->mnt.mnt_flags & MNT_UMOUNT) {
/*
* We have come accross an partially unmounted
* mount in list that has not been visited yet.
* Remember it has been visited and continue
* about our merry way.
*/
list_add_tail(&child->mnt_umounting, &visited);
continue;
}
/* Check the child and parents while progress is made */
while (__propagate_umount(child,
&to_umount, &to_restore)) {
/* Is the parent a umount candidate? */
child = child->mnt_parent;
if (list_empty(&child->mnt_umounting))
break;
}
}
}
umount_list(&to_umount, &to_restore);
restore_mounts(&to_restore);
cleanup_umount_visitations(&visited);
list_splice_tail(&to_umount, list);
return 0;
}
| linux-master | fs/pnode.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/fs.h>
#include <linux/fs_struct.h>
#include <linux/kernel_read_file.h>
#include <linux/security.h>
#include <linux/vmalloc.h>
/**
* kernel_read_file() - read file contents into a kernel buffer
*
* @file: file to read from
* @offset: where to start reading from (see below).
* @buf: pointer to a "void *" buffer for reading into (if
* *@buf is NULL, a buffer will be allocated, and
* @buf_size will be ignored)
* @buf_size: size of buf, if already allocated. If @buf not
* allocated, this is the largest size to allocate.
* @file_size: if non-NULL, the full size of @file will be
* written here.
* @id: the kernel_read_file_id identifying the type of
* file contents being read (for LSMs to examine)
*
* @offset must be 0 unless both @buf and @file_size are non-NULL
* (i.e. the caller must be expecting to read partial file contents
* via an already-allocated @buf, in at most @buf_size chunks, and
* will be able to determine when the entire file was read by
* checking @file_size). This isn't a recommended way to read a
* file, though, since it is possible that the contents might
* change between calls to kernel_read_file().
*
* Returns number of bytes read (no single read will be bigger
* than SSIZE_MAX), or negative on error.
*
*/
ssize_t kernel_read_file(struct file *file, loff_t offset, void **buf,
size_t buf_size, size_t *file_size,
enum kernel_read_file_id id)
{
loff_t i_size, pos;
ssize_t copied;
void *allocated = NULL;
bool whole_file;
int ret;
if (offset != 0 && (!*buf || !file_size))
return -EINVAL;
if (!S_ISREG(file_inode(file)->i_mode))
return -EINVAL;
ret = deny_write_access(file);
if (ret)
return ret;
i_size = i_size_read(file_inode(file));
if (i_size <= 0) {
ret = -EINVAL;
goto out;
}
/* The file is too big for sane activities. */
if (i_size > SSIZE_MAX) {
ret = -EFBIG;
goto out;
}
/* The entire file cannot be read in one buffer. */
if (!file_size && offset == 0 && i_size > buf_size) {
ret = -EFBIG;
goto out;
}
whole_file = (offset == 0 && i_size <= buf_size);
ret = security_kernel_read_file(file, id, whole_file);
if (ret)
goto out;
if (file_size)
*file_size = i_size;
if (!*buf)
*buf = allocated = vmalloc(i_size);
if (!*buf) {
ret = -ENOMEM;
goto out;
}
pos = offset;
copied = 0;
while (copied < buf_size) {
ssize_t bytes;
size_t wanted = min_t(size_t, buf_size - copied,
i_size - pos);
bytes = kernel_read(file, *buf + copied, wanted, &pos);
if (bytes < 0) {
ret = bytes;
goto out_free;
}
if (bytes == 0)
break;
copied += bytes;
}
if (whole_file) {
if (pos != i_size) {
ret = -EIO;
goto out_free;
}
ret = security_kernel_post_read_file(file, *buf, i_size, id);
}
out_free:
if (ret < 0) {
if (allocated) {
vfree(*buf);
*buf = NULL;
}
}
out:
allow_write_access(file);
return ret == 0 ? copied : ret;
}
EXPORT_SYMBOL_GPL(kernel_read_file);
ssize_t kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
size_t buf_size, size_t *file_size,
enum kernel_read_file_id id)
{
struct file *file;
ssize_t ret;
if (!path || !*path)
return -EINVAL;
file = filp_open(path, O_RDONLY, 0);
if (IS_ERR(file))
return PTR_ERR(file);
ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
fput(file);
return ret;
}
EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset,
void **buf, size_t buf_size,
size_t *file_size,
enum kernel_read_file_id id)
{
struct file *file;
struct path root;
ssize_t ret;
if (!path || !*path)
return -EINVAL;
task_lock(&init_task);
get_fs_root(init_task.fs, &root);
task_unlock(&init_task);
file = file_open_root(&root, path, O_RDONLY, 0);
path_put(&root);
if (IS_ERR(file))
return PTR_ERR(file);
ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
fput(file);
return ret;
}
EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
ssize_t kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
size_t buf_size, size_t *file_size,
enum kernel_read_file_id id)
{
struct fd f = fdget(fd);
ssize_t ret = -EBADF;
if (!f.file || !(f.file->f_mode & FMODE_READ))
goto out;
ret = kernel_read_file(f.file, offset, buf, buf_size, file_size, id);
out:
fdput(f);
return ret;
}
EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
| linux-master | fs/kernel_read_file.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/namei.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* Some corrections by tytso.
*/
/* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname
* lookup logic.
*/
/* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture.
*/
#include <linux/init.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/sched/mm.h>
#include <linux/fsnotify.h>
#include <linux/personality.h>
#include <linux/security.h>
#include <linux/ima.h>
#include <linux/syscalls.h>
#include <linux/mount.h>
#include <linux/audit.h>
#include <linux/capability.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/device_cgroup.h>
#include <linux/fs_struct.h>
#include <linux/posix_acl.h>
#include <linux/hash.h>
#include <linux/bitops.h>
#include <linux/init_task.h>
#include <linux/uaccess.h>
#include "internal.h"
#include "mount.h"
/* [Feb-1997 T. Schoebel-Theuer]
* Fundamental changes in the pathname lookup mechanisms (namei)
* were necessary because of omirr. The reason is that omirr needs
* to know the _real_ pathname, not the user-supplied one, in case
* of symlinks (and also when transname replacements occur).
*
* The new code replaces the old recursive symlink resolution with
* an iterative one (in case of non-nested symlink chains). It does
* this with calls to <fs>_follow_link().
* As a side effect, dir_namei(), _namei() and follow_link() are now
* replaced with a single function lookup_dentry() that can handle all
* the special cases of the former code.
*
* With the new dcache, the pathname is stored at each inode, at least as
* long as the refcount of the inode is positive. As a side effect, the
* size of the dcache depends on the inode cache and thus is dynamic.
*
* [29-Apr-1998 C. Scott Ananian] Updated above description of symlink
* resolution to correspond with current state of the code.
*
* Note that the symlink resolution is not *completely* iterative.
* There is still a significant amount of tail- and mid- recursion in
* the algorithm. Also, note that <fs>_readlink() is not used in
* lookup_dentry(): lookup_dentry() on the result of <fs>_readlink()
* may return different results than <fs>_follow_link(). Many virtual
* filesystems (including /proc) exhibit this behavior.
*/
/* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation:
* New symlink semantics: when open() is called with flags O_CREAT | O_EXCL
* and the name already exists in form of a symlink, try to create the new
* name indicated by the symlink. The old code always complained that the
* name already exists, due to not following the symlink even if its target
* is nonexistent. The new semantics affects also mknod() and link() when
* the name is a symlink pointing to a non-existent name.
*
* I don't know which semantics is the right one, since I have no access
* to standards. But I found by trial that HP-UX 9.0 has the full "new"
* semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the
* "old" one. Personally, I think the new semantics is much more logical.
* Note that "ln old new" where "new" is a symlink pointing to a non-existing
* file does succeed in both HP-UX and SunOs, but not in Solaris
* and in the old Linux semantics.
*/
/* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink
* semantics. See the comments in "open_namei" and "do_link" below.
*
* [10-Sep-98 Alan Modra] Another symlink change.
*/
/* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks:
* inside the path - always follow.
* in the last component in creation/removal/renaming - never follow.
* if LOOKUP_FOLLOW passed - follow.
* if the pathname has trailing slashes - follow.
* otherwise - don't follow.
* (applied in that order).
*
* [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT
* restored for 2.4. This is the last surviving part of old 4.2BSD bug.
* During the 2.4 we need to fix the userland stuff depending on it -
* hopefully we will be able to get rid of that wart in 2.5. So far only
* XEmacs seems to be relying on it...
*/
/*
* [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland)
* implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives
* any extra contention...
*/
/* In order to reduce some races, while at the same time doing additional
* checking and hopefully speeding things up, we copy filenames to the
* kernel data space before using them..
*
* POSIX.1 2.4: an empty pathname is invalid (ENOENT).
* PATH_MAX includes the nul terminator --RR.
*/
#define EMBEDDED_NAME_MAX (PATH_MAX - offsetof(struct filename, iname))
struct filename *
getname_flags(const char __user *filename, int flags, int *empty)
{
struct filename *result;
char *kname;
int len;
result = audit_reusename(filename);
if (result)
return result;
result = __getname();
if (unlikely(!result))
return ERR_PTR(-ENOMEM);
/*
* First, try to embed the struct filename inside the names_cache
* allocation
*/
kname = (char *)result->iname;
result->name = kname;
len = strncpy_from_user(kname, filename, EMBEDDED_NAME_MAX);
if (unlikely(len < 0)) {
__putname(result);
return ERR_PTR(len);
}
/*
* Uh-oh. We have a name that's approaching PATH_MAX. Allocate a
* separate struct filename so we can dedicate the entire
* names_cache allocation for the pathname, and re-do the copy from
* userland.
*/
if (unlikely(len == EMBEDDED_NAME_MAX)) {
const size_t size = offsetof(struct filename, iname[1]);
kname = (char *)result;
/*
* size is chosen that way we to guarantee that
* result->iname[0] is within the same object and that
* kname can't be equal to result->iname, no matter what.
*/
result = kzalloc(size, GFP_KERNEL);
if (unlikely(!result)) {
__putname(kname);
return ERR_PTR(-ENOMEM);
}
result->name = kname;
len = strncpy_from_user(kname, filename, PATH_MAX);
if (unlikely(len < 0)) {
__putname(kname);
kfree(result);
return ERR_PTR(len);
}
if (unlikely(len == PATH_MAX)) {
__putname(kname);
kfree(result);
return ERR_PTR(-ENAMETOOLONG);
}
}
result->refcnt = 1;
/* The empty path is special. */
if (unlikely(!len)) {
if (empty)
*empty = 1;
if (!(flags & LOOKUP_EMPTY)) {
putname(result);
return ERR_PTR(-ENOENT);
}
}
result->uptr = filename;
result->aname = NULL;
audit_getname(result);
return result;
}
struct filename *
getname_uflags(const char __user *filename, int uflags)
{
int flags = (uflags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
return getname_flags(filename, flags, NULL);
}
struct filename *
getname(const char __user * filename)
{
return getname_flags(filename, 0, NULL);
}
struct filename *
getname_kernel(const char * filename)
{
struct filename *result;
int len = strlen(filename) + 1;
result = __getname();
if (unlikely(!result))
return ERR_PTR(-ENOMEM);
if (len <= EMBEDDED_NAME_MAX) {
result->name = (char *)result->iname;
} else if (len <= PATH_MAX) {
const size_t size = offsetof(struct filename, iname[1]);
struct filename *tmp;
tmp = kmalloc(size, GFP_KERNEL);
if (unlikely(!tmp)) {
__putname(result);
return ERR_PTR(-ENOMEM);
}
tmp->name = (char *)result;
result = tmp;
} else {
__putname(result);
return ERR_PTR(-ENAMETOOLONG);
}
memcpy((char *)result->name, filename, len);
result->uptr = NULL;
result->aname = NULL;
result->refcnt = 1;
audit_getname(result);
return result;
}
EXPORT_SYMBOL(getname_kernel);
void putname(struct filename *name)
{
if (IS_ERR(name))
return;
BUG_ON(name->refcnt <= 0);
if (--name->refcnt > 0)
return;
if (name->name != name->iname) {
__putname(name->name);
kfree(name);
} else
__putname(name);
}
EXPORT_SYMBOL(putname);
/**
* check_acl - perform ACL permission checking
* @idmap: idmap of the mount the inode was found from
* @inode: inode to check permissions on
* @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC ...)
*
* This function performs the ACL permission checking. Since this function
* retrieve POSIX acls it needs to know whether it is called from a blocking or
* non-blocking context and thus cares about the MAY_NOT_BLOCK bit.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
static int check_acl(struct mnt_idmap *idmap,
struct inode *inode, int mask)
{
#ifdef CONFIG_FS_POSIX_ACL
struct posix_acl *acl;
if (mask & MAY_NOT_BLOCK) {
acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS);
if (!acl)
return -EAGAIN;
/* no ->get_inode_acl() calls in RCU mode... */
if (is_uncached_acl(acl))
return -ECHILD;
return posix_acl_permission(idmap, inode, acl, mask);
}
acl = get_inode_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
int error = posix_acl_permission(idmap, inode, acl, mask);
posix_acl_release(acl);
return error;
}
#endif
return -EAGAIN;
}
/**
* acl_permission_check - perform basic UNIX permission checking
* @idmap: idmap of the mount the inode was found from
* @inode: inode to check permissions on
* @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC ...)
*
* This function performs the basic UNIX permission checking. Since this
* function may retrieve POSIX acls it needs to know whether it is called from a
* blocking or non-blocking context and thus cares about the MAY_NOT_BLOCK bit.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
static int acl_permission_check(struct mnt_idmap *idmap,
struct inode *inode, int mask)
{
unsigned int mode = inode->i_mode;
vfsuid_t vfsuid;
/* Are we the owner? If so, ACL's don't matter */
vfsuid = i_uid_into_vfsuid(idmap, inode);
if (likely(vfsuid_eq_kuid(vfsuid, current_fsuid()))) {
mask &= 7;
mode >>= 6;
return (mask & ~mode) ? -EACCES : 0;
}
/* Do we have ACL's? */
if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
int error = check_acl(idmap, inode, mask);
if (error != -EAGAIN)
return error;
}
/* Only RWX matters for group/other mode bits */
mask &= 7;
/*
* Are the group permissions different from
* the other permissions in the bits we care
* about? Need to check group ownership if so.
*/
if (mask & (mode ^ (mode >> 3))) {
vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
if (vfsgid_in_group_p(vfsgid))
mode >>= 3;
}
/* Bits in 'mode' clear that we require? */
return (mask & ~mode) ? -EACCES : 0;
}
/**
* generic_permission - check for access rights on a Posix-like filesystem
* @idmap: idmap of the mount the inode was found from
* @inode: inode to check access rights for
* @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC,
* %MAY_NOT_BLOCK ...)
*
* Used to check for read/write/execute permissions on a file.
* We use "fsuid" for this, letting us set arbitrary permissions
* for filesystem access without changing the "normal" uids which
* are used for other things.
*
* generic_permission is rcu-walk aware. It returns -ECHILD in case an rcu-walk
* request cannot be satisfied (eg. requires blocking or too much complexity).
* It would then be called again in ref-walk mode.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int generic_permission(struct mnt_idmap *idmap, struct inode *inode,
int mask)
{
int ret;
/*
* Do the basic permission checks.
*/
ret = acl_permission_check(idmap, inode, mask);
if (ret != -EACCES)
return ret;
if (S_ISDIR(inode->i_mode)) {
/* DACs are overridable for directories */
if (!(mask & MAY_WRITE))
if (capable_wrt_inode_uidgid(idmap, inode,
CAP_DAC_READ_SEARCH))
return 0;
if (capable_wrt_inode_uidgid(idmap, inode,
CAP_DAC_OVERRIDE))
return 0;
return -EACCES;
}
/*
* Searching includes executable on directories, else just read.
*/
mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
if (mask == MAY_READ)
if (capable_wrt_inode_uidgid(idmap, inode,
CAP_DAC_READ_SEARCH))
return 0;
/*
* Read/write DACs are always overridable.
* Executable DACs are overridable when there is
* at least one exec bit set.
*/
if (!(mask & MAY_EXEC) || (inode->i_mode & S_IXUGO))
if (capable_wrt_inode_uidgid(idmap, inode,
CAP_DAC_OVERRIDE))
return 0;
return -EACCES;
}
EXPORT_SYMBOL(generic_permission);
/**
* do_inode_permission - UNIX permission checking
* @idmap: idmap of the mount the inode was found from
* @inode: inode to check permissions on
* @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC ...)
*
* We _really_ want to just do "generic_permission()" without
* even looking at the inode->i_op values. So we keep a cache
* flag in inode->i_opflags, that says "this has not special
* permission function, use the fast case".
*/
static inline int do_inode_permission(struct mnt_idmap *idmap,
struct inode *inode, int mask)
{
if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) {
if (likely(inode->i_op->permission))
return inode->i_op->permission(idmap, inode, mask);
/* This gets set once for the inode lifetime */
spin_lock(&inode->i_lock);
inode->i_opflags |= IOP_FASTPERM;
spin_unlock(&inode->i_lock);
}
return generic_permission(idmap, inode, mask);
}
/**
* sb_permission - Check superblock-level permissions
* @sb: Superblock of inode to check permission on
* @inode: Inode to check permission on
* @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
*
* Separate out file-system wide checks from inode-specific permission checks.
*/
static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
{
if (unlikely(mask & MAY_WRITE)) {
umode_t mode = inode->i_mode;
/* Nobody gets write access to a read-only fs. */
if (sb_rdonly(sb) && (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
return -EROFS;
}
return 0;
}
/**
* inode_permission - Check for access rights to a given inode
* @idmap: idmap of the mount the inode was found from
* @inode: Inode to check permission on
* @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
*
* Check for read/write/execute permissions on an inode. We use fs[ug]id for
* this, letting us set arbitrary permissions for filesystem access without
* changing the "normal" UIDs which are used for other things.
*
* When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
*/
int inode_permission(struct mnt_idmap *idmap,
struct inode *inode, int mask)
{
int retval;
retval = sb_permission(inode->i_sb, inode, mask);
if (retval)
return retval;
if (unlikely(mask & MAY_WRITE)) {
/*
* Nobody gets write access to an immutable file.
*/
if (IS_IMMUTABLE(inode))
return -EPERM;
/*
* Updating mtime will likely cause i_uid and i_gid to be
* written back improperly if their true value is unknown
* to the vfs.
*/
if (HAS_UNMAPPED_ID(idmap, inode))
return -EACCES;
}
retval = do_inode_permission(idmap, inode, mask);
if (retval)
return retval;
retval = devcgroup_inode_permission(inode, mask);
if (retval)
return retval;
return security_inode_permission(inode, mask);
}
EXPORT_SYMBOL(inode_permission);
/**
* path_get - get a reference to a path
* @path: path to get the reference to
*
* Given a path increment the reference count to the dentry and the vfsmount.
*/
void path_get(const struct path *path)
{
mntget(path->mnt);
dget(path->dentry);
}
EXPORT_SYMBOL(path_get);
/**
* path_put - put a reference to a path
* @path: path to put the reference to
*
* Given a path decrement the reference count to the dentry and the vfsmount.
*/
void path_put(const struct path *path)
{
dput(path->dentry);
mntput(path->mnt);
}
EXPORT_SYMBOL(path_put);
#define EMBEDDED_LEVELS 2
struct nameidata {
struct path path;
struct qstr last;
struct path root;
struct inode *inode; /* path.dentry.d_inode */
unsigned int flags, state;
unsigned seq, next_seq, m_seq, r_seq;
int last_type;
unsigned depth;
int total_link_count;
struct saved {
struct path link;
struct delayed_call done;
const char *name;
unsigned seq;
} *stack, internal[EMBEDDED_LEVELS];
struct filename *name;
struct nameidata *saved;
unsigned root_seq;
int dfd;
vfsuid_t dir_vfsuid;
umode_t dir_mode;
} __randomize_layout;
#define ND_ROOT_PRESET 1
#define ND_ROOT_GRABBED 2
#define ND_JUMPED 4
static void __set_nameidata(struct nameidata *p, int dfd, struct filename *name)
{
struct nameidata *old = current->nameidata;
p->stack = p->internal;
p->depth = 0;
p->dfd = dfd;
p->name = name;
p->path.mnt = NULL;
p->path.dentry = NULL;
p->total_link_count = old ? old->total_link_count : 0;
p->saved = old;
current->nameidata = p;
}
static inline void set_nameidata(struct nameidata *p, int dfd, struct filename *name,
const struct path *root)
{
__set_nameidata(p, dfd, name);
p->state = 0;
if (unlikely(root)) {
p->state = ND_ROOT_PRESET;
p->root = *root;
}
}
static void restore_nameidata(void)
{
struct nameidata *now = current->nameidata, *old = now->saved;
current->nameidata = old;
if (old)
old->total_link_count = now->total_link_count;
if (now->stack != now->internal)
kfree(now->stack);
}
static bool nd_alloc_stack(struct nameidata *nd)
{
struct saved *p;
p= kmalloc_array(MAXSYMLINKS, sizeof(struct saved),
nd->flags & LOOKUP_RCU ? GFP_ATOMIC : GFP_KERNEL);
if (unlikely(!p))
return false;
memcpy(p, nd->internal, sizeof(nd->internal));
nd->stack = p;
return true;
}
/**
* path_connected - Verify that a dentry is below mnt.mnt_root
* @mnt: The mountpoint to check.
* @dentry: The dentry to check.
*
* Rename can sometimes move a file or directory outside of a bind
* mount, path_connected allows those cases to be detected.
*/
static bool path_connected(struct vfsmount *mnt, struct dentry *dentry)
{
struct super_block *sb = mnt->mnt_sb;
/* Bind mounts can have disconnected paths */
if (mnt->mnt_root == sb->s_root)
return true;
return is_subdir(dentry, mnt->mnt_root);
}
static void drop_links(struct nameidata *nd)
{
int i = nd->depth;
while (i--) {
struct saved *last = nd->stack + i;
do_delayed_call(&last->done);
clear_delayed_call(&last->done);
}
}
static void leave_rcu(struct nameidata *nd)
{
nd->flags &= ~LOOKUP_RCU;
nd->seq = nd->next_seq = 0;
rcu_read_unlock();
}
static void terminate_walk(struct nameidata *nd)
{
drop_links(nd);
if (!(nd->flags & LOOKUP_RCU)) {
int i;
path_put(&nd->path);
for (i = 0; i < nd->depth; i++)
path_put(&nd->stack[i].link);
if (nd->state & ND_ROOT_GRABBED) {
path_put(&nd->root);
nd->state &= ~ND_ROOT_GRABBED;
}
} else {
leave_rcu(nd);
}
nd->depth = 0;
nd->path.mnt = NULL;
nd->path.dentry = NULL;
}
/* path_put is needed afterwards regardless of success or failure */
static bool __legitimize_path(struct path *path, unsigned seq, unsigned mseq)
{
int res = __legitimize_mnt(path->mnt, mseq);
if (unlikely(res)) {
if (res > 0)
path->mnt = NULL;
path->dentry = NULL;
return false;
}
if (unlikely(!lockref_get_not_dead(&path->dentry->d_lockref))) {
path->dentry = NULL;
return false;
}
return !read_seqcount_retry(&path->dentry->d_seq, seq);
}
static inline bool legitimize_path(struct nameidata *nd,
struct path *path, unsigned seq)
{
return __legitimize_path(path, seq, nd->m_seq);
}
static bool legitimize_links(struct nameidata *nd)
{
int i;
if (unlikely(nd->flags & LOOKUP_CACHED)) {
drop_links(nd);
nd->depth = 0;
return false;
}
for (i = 0; i < nd->depth; i++) {
struct saved *last = nd->stack + i;
if (unlikely(!legitimize_path(nd, &last->link, last->seq))) {
drop_links(nd);
nd->depth = i + 1;
return false;
}
}
return true;
}
static bool legitimize_root(struct nameidata *nd)
{
/* Nothing to do if nd->root is zero or is managed by the VFS user. */
if (!nd->root.mnt || (nd->state & ND_ROOT_PRESET))
return true;
nd->state |= ND_ROOT_GRABBED;
return legitimize_path(nd, &nd->root, nd->root_seq);
}
/*
* Path walking has 2 modes, rcu-walk and ref-walk (see
* Documentation/filesystems/path-lookup.txt). In situations when we can't
* continue in RCU mode, we attempt to drop out of rcu-walk mode and grab
* normal reference counts on dentries and vfsmounts to transition to ref-walk
* mode. Refcounts are grabbed at the last known good point before rcu-walk
* got stuck, so ref-walk may continue from there. If this is not successful
* (eg. a seqcount has changed), then failure is returned and it's up to caller
* to restart the path walk from the beginning in ref-walk mode.
*/
/**
* try_to_unlazy - try to switch to ref-walk mode.
* @nd: nameidata pathwalk data
* Returns: true on success, false on failure
*
* try_to_unlazy attempts to legitimize the current nd->path and nd->root
* for ref-walk mode.
* Must be called from rcu-walk context.
* Nothing should touch nameidata between try_to_unlazy() failure and
* terminate_walk().
*/
static bool try_to_unlazy(struct nameidata *nd)
{
struct dentry *parent = nd->path.dentry;
BUG_ON(!(nd->flags & LOOKUP_RCU));
if (unlikely(!legitimize_links(nd)))
goto out1;
if (unlikely(!legitimize_path(nd, &nd->path, nd->seq)))
goto out;
if (unlikely(!legitimize_root(nd)))
goto out;
leave_rcu(nd);
BUG_ON(nd->inode != parent->d_inode);
return true;
out1:
nd->path.mnt = NULL;
nd->path.dentry = NULL;
out:
leave_rcu(nd);
return false;
}
/**
* try_to_unlazy_next - try to switch to ref-walk mode.
* @nd: nameidata pathwalk data
* @dentry: next dentry to step into
* Returns: true on success, false on failure
*
* Similar to try_to_unlazy(), but here we have the next dentry already
* picked by rcu-walk and want to legitimize that in addition to the current
* nd->path and nd->root for ref-walk mode. Must be called from rcu-walk context.
* Nothing should touch nameidata between try_to_unlazy_next() failure and
* terminate_walk().
*/
static bool try_to_unlazy_next(struct nameidata *nd, struct dentry *dentry)
{
int res;
BUG_ON(!(nd->flags & LOOKUP_RCU));
if (unlikely(!legitimize_links(nd)))
goto out2;
res = __legitimize_mnt(nd->path.mnt, nd->m_seq);
if (unlikely(res)) {
if (res > 0)
goto out2;
goto out1;
}
if (unlikely(!lockref_get_not_dead(&nd->path.dentry->d_lockref)))
goto out1;
/*
* We need to move both the parent and the dentry from the RCU domain
* to be properly refcounted. And the sequence number in the dentry
* validates *both* dentry counters, since we checked the sequence
* number of the parent after we got the child sequence number. So we
* know the parent must still be valid if the child sequence number is
*/
if (unlikely(!lockref_get_not_dead(&dentry->d_lockref)))
goto out;
if (read_seqcount_retry(&dentry->d_seq, nd->next_seq))
goto out_dput;
/*
* Sequence counts matched. Now make sure that the root is
* still valid and get it if required.
*/
if (unlikely(!legitimize_root(nd)))
goto out_dput;
leave_rcu(nd);
return true;
out2:
nd->path.mnt = NULL;
out1:
nd->path.dentry = NULL;
out:
leave_rcu(nd);
return false;
out_dput:
leave_rcu(nd);
dput(dentry);
return false;
}
static inline int d_revalidate(struct dentry *dentry, unsigned int flags)
{
if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE))
return dentry->d_op->d_revalidate(dentry, flags);
else
return 1;
}
/**
* complete_walk - successful completion of path walk
* @nd: pointer nameidata
*
* If we had been in RCU mode, drop out of it and legitimize nd->path.
* Revalidate the final result, unless we'd already done that during
* the path walk or the filesystem doesn't ask for it. Return 0 on
* success, -error on failure. In case of failure caller does not
* need to drop nd->path.
*/
static int complete_walk(struct nameidata *nd)
{
struct dentry *dentry = nd->path.dentry;
int status;
if (nd->flags & LOOKUP_RCU) {
/*
* We don't want to zero nd->root for scoped-lookups or
* externally-managed nd->root.
*/
if (!(nd->state & ND_ROOT_PRESET))
if (!(nd->flags & LOOKUP_IS_SCOPED))
nd->root.mnt = NULL;
nd->flags &= ~LOOKUP_CACHED;
if (!try_to_unlazy(nd))
return -ECHILD;
}
if (unlikely(nd->flags & LOOKUP_IS_SCOPED)) {
/*
* While the guarantee of LOOKUP_IS_SCOPED is (roughly) "don't
* ever step outside the root during lookup" and should already
* be guaranteed by the rest of namei, we want to avoid a namei
* BUG resulting in userspace being given a path that was not
* scoped within the root at some point during the lookup.
*
* So, do a final sanity-check to make sure that in the
* worst-case scenario (a complete bypass of LOOKUP_IS_SCOPED)
* we won't silently return an fd completely outside of the
* requested root to userspace.
*
* Userspace could move the path outside the root after this
* check, but as discussed elsewhere this is not a concern (the
* resolved file was inside the root at some point).
*/
if (!path_is_under(&nd->path, &nd->root))
return -EXDEV;
}
if (likely(!(nd->state & ND_JUMPED)))
return 0;
if (likely(!(dentry->d_flags & DCACHE_OP_WEAK_REVALIDATE)))
return 0;
status = dentry->d_op->d_weak_revalidate(dentry, nd->flags);
if (status > 0)
return 0;
if (!status)
status = -ESTALE;
return status;
}
static int set_root(struct nameidata *nd)
{
struct fs_struct *fs = current->fs;
/*
* Jumping to the real root in a scoped-lookup is a BUG in namei, but we
* still have to ensure it doesn't happen because it will cause a breakout
* from the dirfd.
*/
if (WARN_ON(nd->flags & LOOKUP_IS_SCOPED))
return -ENOTRECOVERABLE;
if (nd->flags & LOOKUP_RCU) {
unsigned seq;
do {
seq = read_seqcount_begin(&fs->seq);
nd->root = fs->root;
nd->root_seq = __read_seqcount_begin(&nd->root.dentry->d_seq);
} while (read_seqcount_retry(&fs->seq, seq));
} else {
get_fs_root(fs, &nd->root);
nd->state |= ND_ROOT_GRABBED;
}
return 0;
}
static int nd_jump_root(struct nameidata *nd)
{
if (unlikely(nd->flags & LOOKUP_BENEATH))
return -EXDEV;
if (unlikely(nd->flags & LOOKUP_NO_XDEV)) {
/* Absolute path arguments to path_init() are allowed. */
if (nd->path.mnt != NULL && nd->path.mnt != nd->root.mnt)
return -EXDEV;
}
if (!nd->root.mnt) {
int error = set_root(nd);
if (error)
return error;
}
if (nd->flags & LOOKUP_RCU) {
struct dentry *d;
nd->path = nd->root;
d = nd->path.dentry;
nd->inode = d->d_inode;
nd->seq = nd->root_seq;
if (read_seqcount_retry(&d->d_seq, nd->seq))
return -ECHILD;
} else {
path_put(&nd->path);
nd->path = nd->root;
path_get(&nd->path);
nd->inode = nd->path.dentry->d_inode;
}
nd->state |= ND_JUMPED;
return 0;
}
/*
* Helper to directly jump to a known parsed path from ->get_link,
* caller must have taken a reference to path beforehand.
*/
int nd_jump_link(const struct path *path)
{
int error = -ELOOP;
struct nameidata *nd = current->nameidata;
if (unlikely(nd->flags & LOOKUP_NO_MAGICLINKS))
goto err;
error = -EXDEV;
if (unlikely(nd->flags & LOOKUP_NO_XDEV)) {
if (nd->path.mnt != path->mnt)
goto err;
}
/* Not currently safe for scoped-lookups. */
if (unlikely(nd->flags & LOOKUP_IS_SCOPED))
goto err;
path_put(&nd->path);
nd->path = *path;
nd->inode = nd->path.dentry->d_inode;
nd->state |= ND_JUMPED;
return 0;
err:
path_put(path);
return error;
}
static inline void put_link(struct nameidata *nd)
{
struct saved *last = nd->stack + --nd->depth;
do_delayed_call(&last->done);
if (!(nd->flags & LOOKUP_RCU))
path_put(&last->link);
}
static int sysctl_protected_symlinks __read_mostly;
static int sysctl_protected_hardlinks __read_mostly;
static int sysctl_protected_fifos __read_mostly;
static int sysctl_protected_regular __read_mostly;
#ifdef CONFIG_SYSCTL
static struct ctl_table namei_sysctls[] = {
{
.procname = "protected_symlinks",
.data = &sysctl_protected_symlinks,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "protected_hardlinks",
.data = &sysctl_protected_hardlinks,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "protected_fifos",
.data = &sysctl_protected_fifos,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
},
{
.procname = "protected_regular",
.data = &sysctl_protected_regular,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
},
{ }
};
static int __init init_fs_namei_sysctls(void)
{
register_sysctl_init("fs", namei_sysctls);
return 0;
}
fs_initcall(init_fs_namei_sysctls);
#endif /* CONFIG_SYSCTL */
/**
* may_follow_link - Check symlink following for unsafe situations
* @nd: nameidata pathwalk data
* @inode: Used for idmapping.
*
* In the case of the sysctl_protected_symlinks sysctl being enabled,
* CAP_DAC_OVERRIDE needs to be specifically ignored if the symlink is
* in a sticky world-writable directory. This is to protect privileged
* processes from failing races against path names that may change out
* from under them by way of other users creating malicious symlinks.
* It will permit symlinks to be followed only when outside a sticky
* world-writable directory, or when the uid of the symlink and follower
* match, or when the directory owner matches the symlink's owner.
*
* Returns 0 if following the symlink is allowed, -ve on error.
*/
static inline int may_follow_link(struct nameidata *nd, const struct inode *inode)
{
struct mnt_idmap *idmap;
vfsuid_t vfsuid;
if (!sysctl_protected_symlinks)
return 0;
idmap = mnt_idmap(nd->path.mnt);
vfsuid = i_uid_into_vfsuid(idmap, inode);
/* Allowed if owner and follower match. */
if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
return 0;
/* Allowed if parent directory not sticky and world-writable. */
if ((nd->dir_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH))
return 0;
/* Allowed if parent directory and link owner match. */
if (vfsuid_valid(nd->dir_vfsuid) && vfsuid_eq(nd->dir_vfsuid, vfsuid))
return 0;
if (nd->flags & LOOKUP_RCU)
return -ECHILD;
audit_inode(nd->name, nd->stack[0].link.dentry, 0);
audit_log_path_denied(AUDIT_ANOM_LINK, "follow_link");
return -EACCES;
}
/**
* safe_hardlink_source - Check for safe hardlink conditions
* @idmap: idmap of the mount the inode was found from
* @inode: the source inode to hardlink from
*
* Return false if at least one of the following conditions:
* - inode is not a regular file
* - inode is setuid
* - inode is setgid and group-exec
* - access failure for read and write
*
* Otherwise returns true.
*/
static bool safe_hardlink_source(struct mnt_idmap *idmap,
struct inode *inode)
{
umode_t mode = inode->i_mode;
/* Special files should not get pinned to the filesystem. */
if (!S_ISREG(mode))
return false;
/* Setuid files should not get pinned to the filesystem. */
if (mode & S_ISUID)
return false;
/* Executable setgid files should not get pinned to the filesystem. */
if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
return false;
/* Hardlinking to unreadable or unwritable sources is dangerous. */
if (inode_permission(idmap, inode, MAY_READ | MAY_WRITE))
return false;
return true;
}
/**
* may_linkat - Check permissions for creating a hardlink
* @idmap: idmap of the mount the inode was found from
* @link: the source to hardlink from
*
* Block hardlink when all of:
* - sysctl_protected_hardlinks enabled
* - fsuid does not match inode
* - hardlink source is unsafe (see safe_hardlink_source() above)
* - not CAP_FOWNER in a namespace with the inode owner uid mapped
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply pass @nop_mnt_idmap.
*
* Returns 0 if successful, -ve on error.
*/
int may_linkat(struct mnt_idmap *idmap, const struct path *link)
{
struct inode *inode = link->dentry->d_inode;
/* Inode writeback is not safe when the uid or gid are invalid. */
if (!vfsuid_valid(i_uid_into_vfsuid(idmap, inode)) ||
!vfsgid_valid(i_gid_into_vfsgid(idmap, inode)))
return -EOVERFLOW;
if (!sysctl_protected_hardlinks)
return 0;
/* Source inode owner (or CAP_FOWNER) can hardlink all they like,
* otherwise, it must be a safe source.
*/
if (safe_hardlink_source(idmap, inode) ||
inode_owner_or_capable(idmap, inode))
return 0;
audit_log_path_denied(AUDIT_ANOM_LINK, "linkat");
return -EPERM;
}
/**
* may_create_in_sticky - Check whether an O_CREAT open in a sticky directory
* should be allowed, or not, on files that already
* exist.
* @idmap: idmap of the mount the inode was found from
* @nd: nameidata pathwalk data
* @inode: the inode of the file to open
*
* Block an O_CREAT open of a FIFO (or a regular file) when:
* - sysctl_protected_fifos (or sysctl_protected_regular) is enabled
* - the file already exists
* - we are in a sticky directory
* - we don't own the file
* - the owner of the directory doesn't own the file
* - the directory is world writable
* If the sysctl_protected_fifos (or sysctl_protected_regular) is set to 2
* the directory doesn't have to be world writable: being group writable will
* be enough.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply pass @nop_mnt_idmap.
*
* Returns 0 if the open is allowed, -ve on error.
*/
static int may_create_in_sticky(struct mnt_idmap *idmap,
struct nameidata *nd, struct inode *const inode)
{
umode_t dir_mode = nd->dir_mode;
vfsuid_t dir_vfsuid = nd->dir_vfsuid;
if ((!sysctl_protected_fifos && S_ISFIFO(inode->i_mode)) ||
(!sysctl_protected_regular && S_ISREG(inode->i_mode)) ||
likely(!(dir_mode & S_ISVTX)) ||
vfsuid_eq(i_uid_into_vfsuid(idmap, inode), dir_vfsuid) ||
vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode), current_fsuid()))
return 0;
if (likely(dir_mode & 0002) ||
(dir_mode & 0020 &&
((sysctl_protected_fifos >= 2 && S_ISFIFO(inode->i_mode)) ||
(sysctl_protected_regular >= 2 && S_ISREG(inode->i_mode))))) {
const char *operation = S_ISFIFO(inode->i_mode) ?
"sticky_create_fifo" :
"sticky_create_regular";
audit_log_path_denied(AUDIT_ANOM_CREAT, operation);
return -EACCES;
}
return 0;
}
/*
* follow_up - Find the mountpoint of path's vfsmount
*
* Given a path, find the mountpoint of its source file system.
* Replace @path with the path of the mountpoint in the parent mount.
* Up is towards /.
*
* Return 1 if we went up a level and 0 if we were already at the
* root.
*/
int follow_up(struct path *path)
{
struct mount *mnt = real_mount(path->mnt);
struct mount *parent;
struct dentry *mountpoint;
read_seqlock_excl(&mount_lock);
parent = mnt->mnt_parent;
if (parent == mnt) {
read_sequnlock_excl(&mount_lock);
return 0;
}
mntget(&parent->mnt);
mountpoint = dget(mnt->mnt_mountpoint);
read_sequnlock_excl(&mount_lock);
dput(path->dentry);
path->dentry = mountpoint;
mntput(path->mnt);
path->mnt = &parent->mnt;
return 1;
}
EXPORT_SYMBOL(follow_up);
static bool choose_mountpoint_rcu(struct mount *m, const struct path *root,
struct path *path, unsigned *seqp)
{
while (mnt_has_parent(m)) {
struct dentry *mountpoint = m->mnt_mountpoint;
m = m->mnt_parent;
if (unlikely(root->dentry == mountpoint &&
root->mnt == &m->mnt))
break;
if (mountpoint != m->mnt.mnt_root) {
path->mnt = &m->mnt;
path->dentry = mountpoint;
*seqp = read_seqcount_begin(&mountpoint->d_seq);
return true;
}
}
return false;
}
static bool choose_mountpoint(struct mount *m, const struct path *root,
struct path *path)
{
bool found;
rcu_read_lock();
while (1) {
unsigned seq, mseq = read_seqbegin(&mount_lock);
found = choose_mountpoint_rcu(m, root, path, &seq);
if (unlikely(!found)) {
if (!read_seqretry(&mount_lock, mseq))
break;
} else {
if (likely(__legitimize_path(path, seq, mseq)))
break;
rcu_read_unlock();
path_put(path);
rcu_read_lock();
}
}
rcu_read_unlock();
return found;
}
/*
* Perform an automount
* - return -EISDIR to tell follow_managed() to stop and return the path we
* were called with.
*/
static int follow_automount(struct path *path, int *count, unsigned lookup_flags)
{
struct dentry *dentry = path->dentry;
/* We don't want to mount if someone's just doing a stat -
* unless they're stat'ing a directory and appended a '/' to
* the name.
*
* We do, however, want to mount if someone wants to open or
* create a file of any type under the mountpoint, wants to
* traverse through the mountpoint or wants to open the
* mounted directory. Also, autofs may mark negative dentries
* as being automount points. These will need the attentions
* of the daemon to instantiate them before they can be used.
*/
if (!(lookup_flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
dentry->d_inode)
return -EISDIR;
if (count && (*count)++ >= MAXSYMLINKS)
return -ELOOP;
return finish_automount(dentry->d_op->d_automount(path), path);
}
/*
* mount traversal - out-of-line part. One note on ->d_flags accesses -
* dentries are pinned but not locked here, so negative dentry can go
* positive right under us. Use of smp_load_acquire() provides a barrier
* sufficient for ->d_inode and ->d_flags consistency.
*/
static int __traverse_mounts(struct path *path, unsigned flags, bool *jumped,
int *count, unsigned lookup_flags)
{
struct vfsmount *mnt = path->mnt;
bool need_mntput = false;
int ret = 0;
while (flags & DCACHE_MANAGED_DENTRY) {
/* Allow the filesystem to manage the transit without i_mutex
* being held. */
if (flags & DCACHE_MANAGE_TRANSIT) {
ret = path->dentry->d_op->d_manage(path, false);
flags = smp_load_acquire(&path->dentry->d_flags);
if (ret < 0)
break;
}
if (flags & DCACHE_MOUNTED) { // something's mounted on it..
struct vfsmount *mounted = lookup_mnt(path);
if (mounted) { // ... in our namespace
dput(path->dentry);
if (need_mntput)
mntput(path->mnt);
path->mnt = mounted;
path->dentry = dget(mounted->mnt_root);
// here we know it's positive
flags = path->dentry->d_flags;
need_mntput = true;
continue;
}
}
if (!(flags & DCACHE_NEED_AUTOMOUNT))
break;
// uncovered automount point
ret = follow_automount(path, count, lookup_flags);
flags = smp_load_acquire(&path->dentry->d_flags);
if (ret < 0)
break;
}
if (ret == -EISDIR)
ret = 0;
// possible if you race with several mount --move
if (need_mntput && path->mnt == mnt)
mntput(path->mnt);
if (!ret && unlikely(d_flags_negative(flags)))
ret = -ENOENT;
*jumped = need_mntput;
return ret;
}
static inline int traverse_mounts(struct path *path, bool *jumped,
int *count, unsigned lookup_flags)
{
unsigned flags = smp_load_acquire(&path->dentry->d_flags);
/* fastpath */
if (likely(!(flags & DCACHE_MANAGED_DENTRY))) {
*jumped = false;
if (unlikely(d_flags_negative(flags)))
return -ENOENT;
return 0;
}
return __traverse_mounts(path, flags, jumped, count, lookup_flags);
}
int follow_down_one(struct path *path)
{
struct vfsmount *mounted;
mounted = lookup_mnt(path);
if (mounted) {
dput(path->dentry);
mntput(path->mnt);
path->mnt = mounted;
path->dentry = dget(mounted->mnt_root);
return 1;
}
return 0;
}
EXPORT_SYMBOL(follow_down_one);
/*
* Follow down to the covering mount currently visible to userspace. At each
* point, the filesystem owning that dentry may be queried as to whether the
* caller is permitted to proceed or not.
*/
int follow_down(struct path *path, unsigned int flags)
{
struct vfsmount *mnt = path->mnt;
bool jumped;
int ret = traverse_mounts(path, &jumped, NULL, flags);
if (path->mnt != mnt)
mntput(mnt);
return ret;
}
EXPORT_SYMBOL(follow_down);
/*
* Try to skip to top of mountpoint pile in rcuwalk mode. Fail if
* we meet a managed dentry that would need blocking.
*/
static bool __follow_mount_rcu(struct nameidata *nd, struct path *path)
{
struct dentry *dentry = path->dentry;
unsigned int flags = dentry->d_flags;
if (likely(!(flags & DCACHE_MANAGED_DENTRY)))
return true;
if (unlikely(nd->flags & LOOKUP_NO_XDEV))
return false;
for (;;) {
/*
* Don't forget we might have a non-mountpoint managed dentry
* that wants to block transit.
*/
if (unlikely(flags & DCACHE_MANAGE_TRANSIT)) {
int res = dentry->d_op->d_manage(path, true);
if (res)
return res == -EISDIR;
flags = dentry->d_flags;
}
if (flags & DCACHE_MOUNTED) {
struct mount *mounted = __lookup_mnt(path->mnt, dentry);
if (mounted) {
path->mnt = &mounted->mnt;
dentry = path->dentry = mounted->mnt.mnt_root;
nd->state |= ND_JUMPED;
nd->next_seq = read_seqcount_begin(&dentry->d_seq);
flags = dentry->d_flags;
// makes sure that non-RCU pathwalk could reach
// this state.
if (read_seqretry(&mount_lock, nd->m_seq))
return false;
continue;
}
if (read_seqretry(&mount_lock, nd->m_seq))
return false;
}
return !(flags & DCACHE_NEED_AUTOMOUNT);
}
}
static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry,
struct path *path)
{
bool jumped;
int ret;
path->mnt = nd->path.mnt;
path->dentry = dentry;
if (nd->flags & LOOKUP_RCU) {
unsigned int seq = nd->next_seq;
if (likely(__follow_mount_rcu(nd, path)))
return 0;
// *path and nd->next_seq might've been clobbered
path->mnt = nd->path.mnt;
path->dentry = dentry;
nd->next_seq = seq;
if (!try_to_unlazy_next(nd, dentry))
return -ECHILD;
}
ret = traverse_mounts(path, &jumped, &nd->total_link_count, nd->flags);
if (jumped) {
if (unlikely(nd->flags & LOOKUP_NO_XDEV))
ret = -EXDEV;
else
nd->state |= ND_JUMPED;
}
if (unlikely(ret)) {
dput(path->dentry);
if (path->mnt != nd->path.mnt)
mntput(path->mnt);
}
return ret;
}
/*
* This looks up the name in dcache and possibly revalidates the found dentry.
* NULL is returned if the dentry does not exist in the cache.
*/
static struct dentry *lookup_dcache(const struct qstr *name,
struct dentry *dir,
unsigned int flags)
{
struct dentry *dentry = d_lookup(dir, name);
if (dentry) {
int error = d_revalidate(dentry, flags);
if (unlikely(error <= 0)) {
if (!error)
d_invalidate(dentry);
dput(dentry);
return ERR_PTR(error);
}
}
return dentry;
}
/*
* Parent directory has inode locked exclusive. This is one
* and only case when ->lookup() gets called on non in-lookup
* dentries - as the matter of fact, this only gets called
* when directory is guaranteed to have no in-lookup children
* at all.
*/
struct dentry *lookup_one_qstr_excl(const struct qstr *name,
struct dentry *base,
unsigned int flags)
{
struct dentry *dentry = lookup_dcache(name, base, flags);
struct dentry *old;
struct inode *dir = base->d_inode;
if (dentry)
return dentry;
/* Don't create child dentry for a dead directory. */
if (unlikely(IS_DEADDIR(dir)))
return ERR_PTR(-ENOENT);
dentry = d_alloc(base, name);
if (unlikely(!dentry))
return ERR_PTR(-ENOMEM);
old = dir->i_op->lookup(dir, dentry, flags);
if (unlikely(old)) {
dput(dentry);
dentry = old;
}
return dentry;
}
EXPORT_SYMBOL(lookup_one_qstr_excl);
static struct dentry *lookup_fast(struct nameidata *nd)
{
struct dentry *dentry, *parent = nd->path.dentry;
int status = 1;
/*
* Rename seqlock is not required here because in the off chance
* of a false negative due to a concurrent rename, the caller is
* going to fall back to non-racy lookup.
*/
if (nd->flags & LOOKUP_RCU) {
dentry = __d_lookup_rcu(parent, &nd->last, &nd->next_seq);
if (unlikely(!dentry)) {
if (!try_to_unlazy(nd))
return ERR_PTR(-ECHILD);
return NULL;
}
/*
* This sequence count validates that the parent had no
* changes while we did the lookup of the dentry above.
*/
if (read_seqcount_retry(&parent->d_seq, nd->seq))
return ERR_PTR(-ECHILD);
status = d_revalidate(dentry, nd->flags);
if (likely(status > 0))
return dentry;
if (!try_to_unlazy_next(nd, dentry))
return ERR_PTR(-ECHILD);
if (status == -ECHILD)
/* we'd been told to redo it in non-rcu mode */
status = d_revalidate(dentry, nd->flags);
} else {
dentry = __d_lookup(parent, &nd->last);
if (unlikely(!dentry))
return NULL;
status = d_revalidate(dentry, nd->flags);
}
if (unlikely(status <= 0)) {
if (!status)
d_invalidate(dentry);
dput(dentry);
return ERR_PTR(status);
}
return dentry;
}
/* Fast lookup failed, do it the slow way */
static struct dentry *__lookup_slow(const struct qstr *name,
struct dentry *dir,
unsigned int flags)
{
struct dentry *dentry, *old;
struct inode *inode = dir->d_inode;
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
/* Don't go there if it's already dead */
if (unlikely(IS_DEADDIR(inode)))
return ERR_PTR(-ENOENT);
again:
dentry = d_alloc_parallel(dir, name, &wq);
if (IS_ERR(dentry))
return dentry;
if (unlikely(!d_in_lookup(dentry))) {
int error = d_revalidate(dentry, flags);
if (unlikely(error <= 0)) {
if (!error) {
d_invalidate(dentry);
dput(dentry);
goto again;
}
dput(dentry);
dentry = ERR_PTR(error);
}
} else {
old = inode->i_op->lookup(inode, dentry, flags);
d_lookup_done(dentry);
if (unlikely(old)) {
dput(dentry);
dentry = old;
}
}
return dentry;
}
static struct dentry *lookup_slow(const struct qstr *name,
struct dentry *dir,
unsigned int flags)
{
struct inode *inode = dir->d_inode;
struct dentry *res;
inode_lock_shared(inode);
res = __lookup_slow(name, dir, flags);
inode_unlock_shared(inode);
return res;
}
static inline int may_lookup(struct mnt_idmap *idmap,
struct nameidata *nd)
{
if (nd->flags & LOOKUP_RCU) {
int err = inode_permission(idmap, nd->inode, MAY_EXEC|MAY_NOT_BLOCK);
if (err != -ECHILD || !try_to_unlazy(nd))
return err;
}
return inode_permission(idmap, nd->inode, MAY_EXEC);
}
static int reserve_stack(struct nameidata *nd, struct path *link)
{
if (unlikely(nd->total_link_count++ >= MAXSYMLINKS))
return -ELOOP;
if (likely(nd->depth != EMBEDDED_LEVELS))
return 0;
if (likely(nd->stack != nd->internal))
return 0;
if (likely(nd_alloc_stack(nd)))
return 0;
if (nd->flags & LOOKUP_RCU) {
// we need to grab link before we do unlazy. And we can't skip
// unlazy even if we fail to grab the link - cleanup needs it
bool grabbed_link = legitimize_path(nd, link, nd->next_seq);
if (!try_to_unlazy(nd) || !grabbed_link)
return -ECHILD;
if (nd_alloc_stack(nd))
return 0;
}
return -ENOMEM;
}
enum {WALK_TRAILING = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};
static const char *pick_link(struct nameidata *nd, struct path *link,
struct inode *inode, int flags)
{
struct saved *last;
const char *res;
int error = reserve_stack(nd, link);
if (unlikely(error)) {
if (!(nd->flags & LOOKUP_RCU))
path_put(link);
return ERR_PTR(error);
}
last = nd->stack + nd->depth++;
last->link = *link;
clear_delayed_call(&last->done);
last->seq = nd->next_seq;
if (flags & WALK_TRAILING) {
error = may_follow_link(nd, inode);
if (unlikely(error))
return ERR_PTR(error);
}
if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS) ||
unlikely(link->mnt->mnt_flags & MNT_NOSYMFOLLOW))
return ERR_PTR(-ELOOP);
if (!(nd->flags & LOOKUP_RCU)) {
touch_atime(&last->link);
cond_resched();
} else if (atime_needs_update(&last->link, inode)) {
if (!try_to_unlazy(nd))
return ERR_PTR(-ECHILD);
touch_atime(&last->link);
}
error = security_inode_follow_link(link->dentry, inode,
nd->flags & LOOKUP_RCU);
if (unlikely(error))
return ERR_PTR(error);
res = READ_ONCE(inode->i_link);
if (!res) {
const char * (*get)(struct dentry *, struct inode *,
struct delayed_call *);
get = inode->i_op->get_link;
if (nd->flags & LOOKUP_RCU) {
res = get(NULL, inode, &last->done);
if (res == ERR_PTR(-ECHILD) && try_to_unlazy(nd))
res = get(link->dentry, inode, &last->done);
} else {
res = get(link->dentry, inode, &last->done);
}
if (!res)
goto all_done;
if (IS_ERR(res))
return res;
}
if (*res == '/') {
error = nd_jump_root(nd);
if (unlikely(error))
return ERR_PTR(error);
while (unlikely(*++res == '/'))
;
}
if (*res)
return res;
all_done: // pure jump
put_link(nd);
return NULL;
}
/*
* Do we need to follow links? We _really_ want to be able
* to do this check without having to look at inode->i_op,
* so we keep a cache of "no, this doesn't need follow_link"
* for the common case.
*
* NOTE: dentry must be what nd->next_seq had been sampled from.
*/
static const char *step_into(struct nameidata *nd, int flags,
struct dentry *dentry)
{
struct path path;
struct inode *inode;
int err = handle_mounts(nd, dentry, &path);
if (err < 0)
return ERR_PTR(err);
inode = path.dentry->d_inode;
if (likely(!d_is_symlink(path.dentry)) ||
((flags & WALK_TRAILING) && !(nd->flags & LOOKUP_FOLLOW)) ||
(flags & WALK_NOFOLLOW)) {
/* not a symlink or should not follow */
if (nd->flags & LOOKUP_RCU) {
if (read_seqcount_retry(&path.dentry->d_seq, nd->next_seq))
return ERR_PTR(-ECHILD);
if (unlikely(!inode))
return ERR_PTR(-ENOENT);
} else {
dput(nd->path.dentry);
if (nd->path.mnt != path.mnt)
mntput(nd->path.mnt);
}
nd->path = path;
nd->inode = inode;
nd->seq = nd->next_seq;
return NULL;
}
if (nd->flags & LOOKUP_RCU) {
/* make sure that d_is_symlink above matches inode */
if (read_seqcount_retry(&path.dentry->d_seq, nd->next_seq))
return ERR_PTR(-ECHILD);
} else {
if (path.mnt == nd->path.mnt)
mntget(path.mnt);
}
return pick_link(nd, &path, inode, flags);
}
static struct dentry *follow_dotdot_rcu(struct nameidata *nd)
{
struct dentry *parent, *old;
if (path_equal(&nd->path, &nd->root))
goto in_root;
if (unlikely(nd->path.dentry == nd->path.mnt->mnt_root)) {
struct path path;
unsigned seq;
if (!choose_mountpoint_rcu(real_mount(nd->path.mnt),
&nd->root, &path, &seq))
goto in_root;
if (unlikely(nd->flags & LOOKUP_NO_XDEV))
return ERR_PTR(-ECHILD);
nd->path = path;
nd->inode = path.dentry->d_inode;
nd->seq = seq;
// makes sure that non-RCU pathwalk could reach this state
if (read_seqretry(&mount_lock, nd->m_seq))
return ERR_PTR(-ECHILD);
/* we know that mountpoint was pinned */
}
old = nd->path.dentry;
parent = old->d_parent;
nd->next_seq = read_seqcount_begin(&parent->d_seq);
// makes sure that non-RCU pathwalk could reach this state
if (read_seqcount_retry(&old->d_seq, nd->seq))
return ERR_PTR(-ECHILD);
if (unlikely(!path_connected(nd->path.mnt, parent)))
return ERR_PTR(-ECHILD);
return parent;
in_root:
if (read_seqretry(&mount_lock, nd->m_seq))
return ERR_PTR(-ECHILD);
if (unlikely(nd->flags & LOOKUP_BENEATH))
return ERR_PTR(-ECHILD);
nd->next_seq = nd->seq;
return nd->path.dentry;
}
static struct dentry *follow_dotdot(struct nameidata *nd)
{
struct dentry *parent;
if (path_equal(&nd->path, &nd->root))
goto in_root;
if (unlikely(nd->path.dentry == nd->path.mnt->mnt_root)) {
struct path path;
if (!choose_mountpoint(real_mount(nd->path.mnt),
&nd->root, &path))
goto in_root;
path_put(&nd->path);
nd->path = path;
nd->inode = path.dentry->d_inode;
if (unlikely(nd->flags & LOOKUP_NO_XDEV))
return ERR_PTR(-EXDEV);
}
/* rare case of legitimate dget_parent()... */
parent = dget_parent(nd->path.dentry);
if (unlikely(!path_connected(nd->path.mnt, parent))) {
dput(parent);
return ERR_PTR(-ENOENT);
}
return parent;
in_root:
if (unlikely(nd->flags & LOOKUP_BENEATH))
return ERR_PTR(-EXDEV);
return dget(nd->path.dentry);
}
static const char *handle_dots(struct nameidata *nd, int type)
{
if (type == LAST_DOTDOT) {
const char *error = NULL;
struct dentry *parent;
if (!nd->root.mnt) {
error = ERR_PTR(set_root(nd));
if (error)
return error;
}
if (nd->flags & LOOKUP_RCU)
parent = follow_dotdot_rcu(nd);
else
parent = follow_dotdot(nd);
if (IS_ERR(parent))
return ERR_CAST(parent);
error = step_into(nd, WALK_NOFOLLOW, parent);
if (unlikely(error))
return error;
if (unlikely(nd->flags & LOOKUP_IS_SCOPED)) {
/*
* If there was a racing rename or mount along our
* path, then we can't be sure that ".." hasn't jumped
* above nd->root (and so userspace should retry or use
* some fallback).
*/
smp_rmb();
if (__read_seqcount_retry(&mount_lock.seqcount, nd->m_seq))
return ERR_PTR(-EAGAIN);
if (__read_seqcount_retry(&rename_lock.seqcount, nd->r_seq))
return ERR_PTR(-EAGAIN);
}
}
return NULL;
}
static const char *walk_component(struct nameidata *nd, int flags)
{
struct dentry *dentry;
/*
* "." and ".." are special - ".." especially so because it has
* to be able to know about the current root directory and
* parent relationships.
*/
if (unlikely(nd->last_type != LAST_NORM)) {
if (!(flags & WALK_MORE) && nd->depth)
put_link(nd);
return handle_dots(nd, nd->last_type);
}
dentry = lookup_fast(nd);
if (IS_ERR(dentry))
return ERR_CAST(dentry);
if (unlikely(!dentry)) {
dentry = lookup_slow(&nd->last, nd->path.dentry, nd->flags);
if (IS_ERR(dentry))
return ERR_CAST(dentry);
}
if (!(flags & WALK_MORE) && nd->depth)
put_link(nd);
return step_into(nd, flags, dentry);
}
/*
* We can do the critical dentry name comparison and hashing
* operations one word at a time, but we are limited to:
*
* - Architectures with fast unaligned word accesses. We could
* do a "get_unaligned()" if this helps and is sufficiently
* fast.
*
* - non-CONFIG_DEBUG_PAGEALLOC configurations (so that we
* do not trap on the (extremely unlikely) case of a page
* crossing operation.
*
* - Furthermore, we need an efficient 64-bit compile for the
* 64-bit case in order to generate the "number of bytes in
* the final mask". Again, that could be replaced with a
* efficient population count instruction or similar.
*/
#ifdef CONFIG_DCACHE_WORD_ACCESS
#include <asm/word-at-a-time.h>
#ifdef HASH_MIX
/* Architecture provides HASH_MIX and fold_hash() in <asm/hash.h> */
#elif defined(CONFIG_64BIT)
/*
* Register pressure in the mixing function is an issue, particularly
* on 32-bit x86, but almost any function requires one state value and
* one temporary. Instead, use a function designed for two state values
* and no temporaries.
*
* This function cannot create a collision in only two iterations, so
* we have two iterations to achieve avalanche. In those two iterations,
* we have six layers of mixing, which is enough to spread one bit's
* influence out to 2^6 = 64 state bits.
*
* Rotate constants are scored by considering either 64 one-bit input
* deltas or 64*63/2 = 2016 two-bit input deltas, and finding the
* probability of that delta causing a change to each of the 128 output
* bits, using a sample of random initial states.
*
* The Shannon entropy of the computed probabilities is then summed
* to produce a score. Ideally, any input change has a 50% chance of
* toggling any given output bit.
*
* Mixing scores (in bits) for (12,45):
* Input delta: 1-bit 2-bit
* 1 round: 713.3 42542.6
* 2 rounds: 2753.7 140389.8
* 3 rounds: 5954.1 233458.2
* 4 rounds: 7862.6 256672.2
* Perfect: 8192 258048
* (64*128) (64*63/2 * 128)
*/
#define HASH_MIX(x, y, a) \
( x ^= (a), \
y ^= x, x = rol64(x,12),\
x += y, y = rol64(y,45),\
y *= 9 )
/*
* Fold two longs into one 32-bit hash value. This must be fast, but
* latency isn't quite as critical, as there is a fair bit of additional
* work done before the hash value is used.
*/
static inline unsigned int fold_hash(unsigned long x, unsigned long y)
{
y ^= x * GOLDEN_RATIO_64;
y *= GOLDEN_RATIO_64;
return y >> 32;
}
#else /* 32-bit case */
/*
* Mixing scores (in bits) for (7,20):
* Input delta: 1-bit 2-bit
* 1 round: 330.3 9201.6
* 2 rounds: 1246.4 25475.4
* 3 rounds: 1907.1 31295.1
* 4 rounds: 2042.3 31718.6
* Perfect: 2048 31744
* (32*64) (32*31/2 * 64)
*/
#define HASH_MIX(x, y, a) \
( x ^= (a), \
y ^= x, x = rol32(x, 7),\
x += y, y = rol32(y,20),\
y *= 9 )
static inline unsigned int fold_hash(unsigned long x, unsigned long y)
{
/* Use arch-optimized multiply if one exists */
return __hash_32(y ^ __hash_32(x));
}
#endif
/*
* Return the hash of a string of known length. This is carfully
* designed to match hash_name(), which is the more critical function.
* In particular, we must end by hashing a final word containing 0..7
* payload bytes, to match the way that hash_name() iterates until it
* finds the delimiter after the name.
*/
unsigned int full_name_hash(const void *salt, const char *name, unsigned int len)
{
unsigned long a, x = 0, y = (unsigned long)salt;
for (;;) {
if (!len)
goto done;
a = load_unaligned_zeropad(name);
if (len < sizeof(unsigned long))
break;
HASH_MIX(x, y, a);
name += sizeof(unsigned long);
len -= sizeof(unsigned long);
}
x ^= a & bytemask_from_count(len);
done:
return fold_hash(x, y);
}
EXPORT_SYMBOL(full_name_hash);
/* Return the "hash_len" (hash and length) of a null-terminated string */
u64 hashlen_string(const void *salt, const char *name)
{
unsigned long a = 0, x = 0, y = (unsigned long)salt;
unsigned long adata, mask, len;
const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
len = 0;
goto inside;
do {
HASH_MIX(x, y, a);
len += sizeof(unsigned long);
inside:
a = load_unaligned_zeropad(name+len);
} while (!has_zero(a, &adata, &constants));
adata = prep_zero_mask(a, adata, &constants);
mask = create_zero_mask(adata);
x ^= a & zero_bytemask(mask);
return hashlen_create(fold_hash(x, y), len + find_zero(mask));
}
EXPORT_SYMBOL(hashlen_string);
/*
* Calculate the length and hash of the path component, and
* return the "hash_len" as the result.
*/
static inline u64 hash_name(const void *salt, const char *name)
{
unsigned long a = 0, b, x = 0, y = (unsigned long)salt;
unsigned long adata, bdata, mask, len;
const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
len = 0;
goto inside;
do {
HASH_MIX(x, y, a);
len += sizeof(unsigned long);
inside:
a = load_unaligned_zeropad(name+len);
b = a ^ REPEAT_BYTE('/');
} while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
adata = prep_zero_mask(a, adata, &constants);
bdata = prep_zero_mask(b, bdata, &constants);
mask = create_zero_mask(adata | bdata);
x ^= a & zero_bytemask(mask);
return hashlen_create(fold_hash(x, y), len + find_zero(mask));
}
#else /* !CONFIG_DCACHE_WORD_ACCESS: Slow, byte-at-a-time version */
/* Return the hash of a string of known length */
unsigned int full_name_hash(const void *salt, const char *name, unsigned int len)
{
unsigned long hash = init_name_hash(salt);
while (len--)
hash = partial_name_hash((unsigned char)*name++, hash);
return end_name_hash(hash);
}
EXPORT_SYMBOL(full_name_hash);
/* Return the "hash_len" (hash and length) of a null-terminated string */
u64 hashlen_string(const void *salt, const char *name)
{
unsigned long hash = init_name_hash(salt);
unsigned long len = 0, c;
c = (unsigned char)*name;
while (c) {
len++;
hash = partial_name_hash(c, hash);
c = (unsigned char)name[len];
}
return hashlen_create(end_name_hash(hash), len);
}
EXPORT_SYMBOL(hashlen_string);
/*
* We know there's a real path component here of at least
* one character.
*/
static inline u64 hash_name(const void *salt, const char *name)
{
unsigned long hash = init_name_hash(salt);
unsigned long len = 0, c;
c = (unsigned char)*name;
do {
len++;
hash = partial_name_hash(c, hash);
c = (unsigned char)name[len];
} while (c && c != '/');
return hashlen_create(end_name_hash(hash), len);
}
#endif
/*
* Name resolution.
* This is the basic name resolution function, turning a pathname into
* the final dentry. We expect 'base' to be positive and a directory.
*
* Returns 0 and nd will have valid dentry and mnt on success.
* Returns error and drops reference to input namei data on failure.
*/
static int link_path_walk(const char *name, struct nameidata *nd)
{
int depth = 0; // depth <= nd->depth
int err;
nd->last_type = LAST_ROOT;
nd->flags |= LOOKUP_PARENT;
if (IS_ERR(name))
return PTR_ERR(name);
while (*name=='/')
name++;
if (!*name) {
nd->dir_mode = 0; // short-circuit the 'hardening' idiocy
return 0;
}
/* At this point we know we have a real path component. */
for(;;) {
struct mnt_idmap *idmap;
const char *link;
u64 hash_len;
int type;
idmap = mnt_idmap(nd->path.mnt);
err = may_lookup(idmap, nd);
if (err)
return err;
hash_len = hash_name(nd->path.dentry, name);
type = LAST_NORM;
if (name[0] == '.') switch (hashlen_len(hash_len)) {
case 2:
if (name[1] == '.') {
type = LAST_DOTDOT;
nd->state |= ND_JUMPED;
}
break;
case 1:
type = LAST_DOT;
}
if (likely(type == LAST_NORM)) {
struct dentry *parent = nd->path.dentry;
nd->state &= ~ND_JUMPED;
if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
struct qstr this = { { .hash_len = hash_len }, .name = name };
err = parent->d_op->d_hash(parent, &this);
if (err < 0)
return err;
hash_len = this.hash_len;
name = this.name;
}
}
nd->last.hash_len = hash_len;
nd->last.name = name;
nd->last_type = type;
name += hashlen_len(hash_len);
if (!*name)
goto OK;
/*
* If it wasn't NUL, we know it was '/'. Skip that
* slash, and continue until no more slashes.
*/
do {
name++;
} while (unlikely(*name == '/'));
if (unlikely(!*name)) {
OK:
/* pathname or trailing symlink, done */
if (!depth) {
nd->dir_vfsuid = i_uid_into_vfsuid(idmap, nd->inode);
nd->dir_mode = nd->inode->i_mode;
nd->flags &= ~LOOKUP_PARENT;
return 0;
}
/* last component of nested symlink */
name = nd->stack[--depth].name;
link = walk_component(nd, 0);
} else {
/* not the last component */
link = walk_component(nd, WALK_MORE);
}
if (unlikely(link)) {
if (IS_ERR(link))
return PTR_ERR(link);
/* a symlink to follow */
nd->stack[depth++].name = name;
name = link;
continue;
}
if (unlikely(!d_can_lookup(nd->path.dentry))) {
if (nd->flags & LOOKUP_RCU) {
if (!try_to_unlazy(nd))
return -ECHILD;
}
return -ENOTDIR;
}
}
}
/* must be paired with terminate_walk() */
static const char *path_init(struct nameidata *nd, unsigned flags)
{
int error;
const char *s = nd->name->name;
/* LOOKUP_CACHED requires RCU, ask caller to retry */
if ((flags & (LOOKUP_RCU | LOOKUP_CACHED)) == LOOKUP_CACHED)
return ERR_PTR(-EAGAIN);
if (!*s)
flags &= ~LOOKUP_RCU;
if (flags & LOOKUP_RCU)
rcu_read_lock();
else
nd->seq = nd->next_seq = 0;
nd->flags = flags;
nd->state |= ND_JUMPED;
nd->m_seq = __read_seqcount_begin(&mount_lock.seqcount);
nd->r_seq = __read_seqcount_begin(&rename_lock.seqcount);
smp_rmb();
if (nd->state & ND_ROOT_PRESET) {
struct dentry *root = nd->root.dentry;
struct inode *inode = root->d_inode;
if (*s && unlikely(!d_can_lookup(root)))
return ERR_PTR(-ENOTDIR);
nd->path = nd->root;
nd->inode = inode;
if (flags & LOOKUP_RCU) {
nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
nd->root_seq = nd->seq;
} else {
path_get(&nd->path);
}
return s;
}
nd->root.mnt = NULL;
/* Absolute pathname -- fetch the root (LOOKUP_IN_ROOT uses nd->dfd). */
if (*s == '/' && !(flags & LOOKUP_IN_ROOT)) {
error = nd_jump_root(nd);
if (unlikely(error))
return ERR_PTR(error);
return s;
}
/* Relative pathname -- get the starting-point it is relative to. */
if (nd->dfd == AT_FDCWD) {
if (flags & LOOKUP_RCU) {
struct fs_struct *fs = current->fs;
unsigned seq;
do {
seq = read_seqcount_begin(&fs->seq);
nd->path = fs->pwd;
nd->inode = nd->path.dentry->d_inode;
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
} while (read_seqcount_retry(&fs->seq, seq));
} else {
get_fs_pwd(current->fs, &nd->path);
nd->inode = nd->path.dentry->d_inode;
}
} else {
/* Caller must check execute permissions on the starting path component */
struct fd f = fdget_raw(nd->dfd);
struct dentry *dentry;
if (!f.file)
return ERR_PTR(-EBADF);
dentry = f.file->f_path.dentry;
if (*s && unlikely(!d_can_lookup(dentry))) {
fdput(f);
return ERR_PTR(-ENOTDIR);
}
nd->path = f.file->f_path;
if (flags & LOOKUP_RCU) {
nd->inode = nd->path.dentry->d_inode;
nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
} else {
path_get(&nd->path);
nd->inode = nd->path.dentry->d_inode;
}
fdput(f);
}
/* For scoped-lookups we need to set the root to the dirfd as well. */
if (flags & LOOKUP_IS_SCOPED) {
nd->root = nd->path;
if (flags & LOOKUP_RCU) {
nd->root_seq = nd->seq;
} else {
path_get(&nd->root);
nd->state |= ND_ROOT_GRABBED;
}
}
return s;
}
static inline const char *lookup_last(struct nameidata *nd)
{
if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
return walk_component(nd, WALK_TRAILING);
}
static int handle_lookup_down(struct nameidata *nd)
{
if (!(nd->flags & LOOKUP_RCU))
dget(nd->path.dentry);
nd->next_seq = nd->seq;
return PTR_ERR(step_into(nd, WALK_NOFOLLOW, nd->path.dentry));
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path)
{
const char *s = path_init(nd, flags);
int err;
if (unlikely(flags & LOOKUP_DOWN) && !IS_ERR(s)) {
err = handle_lookup_down(nd);
if (unlikely(err < 0))
s = ERR_PTR(err);
}
while (!(err = link_path_walk(s, nd)) &&
(s = lookup_last(nd)) != NULL)
;
if (!err && unlikely(nd->flags & LOOKUP_MOUNTPOINT)) {
err = handle_lookup_down(nd);
nd->state &= ~ND_JUMPED; // no d_weak_revalidate(), please...
}
if (!err)
err = complete_walk(nd);
if (!err && nd->flags & LOOKUP_DIRECTORY)
if (!d_can_lookup(nd->path.dentry))
err = -ENOTDIR;
if (!err) {
*path = nd->path;
nd->path.mnt = NULL;
nd->path.dentry = NULL;
}
terminate_walk(nd);
return err;
}
int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root)
{
int retval;
struct nameidata nd;
if (IS_ERR(name))
return PTR_ERR(name);
set_nameidata(&nd, dfd, name, root);
retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
if (unlikely(retval == -ECHILD))
retval = path_lookupat(&nd, flags, path);
if (unlikely(retval == -ESTALE))
retval = path_lookupat(&nd, flags | LOOKUP_REVAL, path);
if (likely(!retval))
audit_inode(name, path->dentry,
flags & LOOKUP_MOUNTPOINT ? AUDIT_INODE_NOEVAL : 0);
restore_nameidata();
return retval;
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_parentat(struct nameidata *nd, unsigned flags,
struct path *parent)
{
const char *s = path_init(nd, flags);
int err = link_path_walk(s, nd);
if (!err)
err = complete_walk(nd);
if (!err) {
*parent = nd->path;
nd->path.mnt = NULL;
nd->path.dentry = NULL;
}
terminate_walk(nd);
return err;
}
/* Note: this does not consume "name" */
static int __filename_parentat(int dfd, struct filename *name,
unsigned int flags, struct path *parent,
struct qstr *last, int *type,
const struct path *root)
{
int retval;
struct nameidata nd;
if (IS_ERR(name))
return PTR_ERR(name);
set_nameidata(&nd, dfd, name, root);
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
if (unlikely(retval == -ECHILD))
retval = path_parentat(&nd, flags, parent);
if (unlikely(retval == -ESTALE))
retval = path_parentat(&nd, flags | LOOKUP_REVAL, parent);
if (likely(!retval)) {
*last = nd.last;
*type = nd.last_type;
audit_inode(name, parent->dentry, AUDIT_INODE_PARENT);
}
restore_nameidata();
return retval;
}
static int filename_parentat(int dfd, struct filename *name,
unsigned int flags, struct path *parent,
struct qstr *last, int *type)
{
return __filename_parentat(dfd, name, flags, parent, last, type, NULL);
}
/* does lookup, returns the object with parent locked */
static struct dentry *__kern_path_locked(struct filename *name, struct path *path)
{
struct dentry *d;
struct qstr last;
int type, error;
error = filename_parentat(AT_FDCWD, name, 0, path, &last, &type);
if (error)
return ERR_PTR(error);
if (unlikely(type != LAST_NORM)) {
path_put(path);
return ERR_PTR(-EINVAL);
}
inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
d = lookup_one_qstr_excl(&last, path->dentry, 0);
if (IS_ERR(d)) {
inode_unlock(path->dentry->d_inode);
path_put(path);
}
return d;
}
struct dentry *kern_path_locked(const char *name, struct path *path)
{
struct filename *filename = getname_kernel(name);
struct dentry *res = __kern_path_locked(filename, path);
putname(filename);
return res;
}
int kern_path(const char *name, unsigned int flags, struct path *path)
{
struct filename *filename = getname_kernel(name);
int ret = filename_lookup(AT_FDCWD, filename, flags, path, NULL);
putname(filename);
return ret;
}
EXPORT_SYMBOL(kern_path);
/**
* vfs_path_parent_lookup - lookup a parent path relative to a dentry-vfsmount pair
* @filename: filename structure
* @flags: lookup flags
* @parent: pointer to struct path to fill
* @last: last component
* @type: type of the last component
* @root: pointer to struct path of the base directory
*/
int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,
struct path *parent, struct qstr *last, int *type,
const struct path *root)
{
return __filename_parentat(AT_FDCWD, filename, flags, parent, last,
type, root);
}
EXPORT_SYMBOL(vfs_path_parent_lookup);
/**
* vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
* @dentry: pointer to dentry of the base directory
* @mnt: pointer to vfs mount of the base directory
* @name: pointer to file name
* @flags: lookup flags
* @path: pointer to struct path to fill
*/
int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
const char *name, unsigned int flags,
struct path *path)
{
struct filename *filename;
struct path root = {.mnt = mnt, .dentry = dentry};
int ret;
filename = getname_kernel(name);
/* the first argument of filename_lookup() is ignored with root */
ret = filename_lookup(AT_FDCWD, filename, flags, path, &root);
putname(filename);
return ret;
}
EXPORT_SYMBOL(vfs_path_lookup);
static int lookup_one_common(struct mnt_idmap *idmap,
const char *name, struct dentry *base, int len,
struct qstr *this)
{
this->name = name;
this->len = len;
this->hash = full_name_hash(base, name, len);
if (!len)
return -EACCES;
if (unlikely(name[0] == '.')) {
if (len < 2 || (len == 2 && name[1] == '.'))
return -EACCES;
}
while (len--) {
unsigned int c = *(const unsigned char *)name++;
if (c == '/' || c == '\0')
return -EACCES;
}
/*
* See if the low-level filesystem might want
* to use its own hash..
*/
if (base->d_flags & DCACHE_OP_HASH) {
int err = base->d_op->d_hash(base, this);
if (err < 0)
return err;
}
return inode_permission(idmap, base->d_inode, MAY_EXEC);
}
/**
* try_lookup_one_len - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
*
* Look up a dentry by name in the dcache, returning NULL if it does not
* currently exist. The function does not try to create a dentry.
*
* Note that this routine is purely a helper for filesystem usage and should
* not be called by generic code.
*
* The caller must hold base->i_mutex.
*/
struct dentry *try_lookup_one_len(const char *name, struct dentry *base, int len)
{
struct qstr this;
int err;
WARN_ON_ONCE(!inode_is_locked(base->d_inode));
err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this);
if (err)
return ERR_PTR(err);
return lookup_dcache(&this, base, 0);
}
EXPORT_SYMBOL(try_lookup_one_len);
/**
* lookup_one_len - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
*
* Note that this routine is purely a helper for filesystem usage and should
* not be called by generic code.
*
* The caller must hold base->i_mutex.
*/
struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
{
struct dentry *dentry;
struct qstr this;
int err;
WARN_ON_ONCE(!inode_is_locked(base->d_inode));
err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this);
if (err)
return ERR_PTR(err);
dentry = lookup_dcache(&this, base, 0);
return dentry ? dentry : __lookup_slow(&this, base, 0);
}
EXPORT_SYMBOL(lookup_one_len);
/**
* lookup_one - filesystem helper to lookup single pathname component
* @idmap: idmap of the mount the lookup is performed from
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
*
* Note that this routine is purely a helper for filesystem usage and should
* not be called by generic code.
*
* The caller must hold base->i_mutex.
*/
struct dentry *lookup_one(struct mnt_idmap *idmap, const char *name,
struct dentry *base, int len)
{
struct dentry *dentry;
struct qstr this;
int err;
WARN_ON_ONCE(!inode_is_locked(base->d_inode));
err = lookup_one_common(idmap, name, base, len, &this);
if (err)
return ERR_PTR(err);
dentry = lookup_dcache(&this, base, 0);
return dentry ? dentry : __lookup_slow(&this, base, 0);
}
EXPORT_SYMBOL(lookup_one);
/**
* lookup_one_unlocked - filesystem helper to lookup single pathname component
* @idmap: idmap of the mount the lookup is performed from
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
*
* Note that this routine is purely a helper for filesystem usage and should
* not be called by generic code.
*
* Unlike lookup_one_len, it should be called without the parent
* i_mutex held, and will take the i_mutex itself if necessary.
*/
struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap,
const char *name, struct dentry *base,
int len)
{
struct qstr this;
int err;
struct dentry *ret;
err = lookup_one_common(idmap, name, base, len, &this);
if (err)
return ERR_PTR(err);
ret = lookup_dcache(&this, base, 0);
if (!ret)
ret = lookup_slow(&this, base, 0);
return ret;
}
EXPORT_SYMBOL(lookup_one_unlocked);
/**
* lookup_one_positive_unlocked - filesystem helper to lookup single
* pathname component
* @idmap: idmap of the mount the lookup is performed from
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
*
* This helper will yield ERR_PTR(-ENOENT) on negatives. The helper returns
* known positive or ERR_PTR(). This is what most of the users want.
*
* Note that pinned negative with unlocked parent _can_ become positive at any
* time, so callers of lookup_one_unlocked() need to be very careful; pinned
* positives have >d_inode stable, so this one avoids such problems.
*
* Note that this routine is purely a helper for filesystem usage and should
* not be called by generic code.
*
* The helper should be called without i_mutex held.
*/
struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap,
const char *name,
struct dentry *base, int len)
{
struct dentry *ret = lookup_one_unlocked(idmap, name, base, len);
if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
dput(ret);
ret = ERR_PTR(-ENOENT);
}
return ret;
}
EXPORT_SYMBOL(lookup_one_positive_unlocked);
/**
* lookup_one_len_unlocked - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
*
* Note that this routine is purely a helper for filesystem usage and should
* not be called by generic code.
*
* Unlike lookup_one_len, it should be called without the parent
* i_mutex held, and will take the i_mutex itself if necessary.
*/
struct dentry *lookup_one_len_unlocked(const char *name,
struct dentry *base, int len)
{
return lookup_one_unlocked(&nop_mnt_idmap, name, base, len);
}
EXPORT_SYMBOL(lookup_one_len_unlocked);
/*
* Like lookup_one_len_unlocked(), except that it yields ERR_PTR(-ENOENT)
* on negatives. Returns known positive or ERR_PTR(); that's what
* most of the users want. Note that pinned negative with unlocked parent
* _can_ become positive at any time, so callers of lookup_one_len_unlocked()
* need to be very careful; pinned positives have ->d_inode stable, so
* this one avoids such problems.
*/
struct dentry *lookup_positive_unlocked(const char *name,
struct dentry *base, int len)
{
return lookup_one_positive_unlocked(&nop_mnt_idmap, name, base, len);
}
EXPORT_SYMBOL(lookup_positive_unlocked);
#ifdef CONFIG_UNIX98_PTYS
int path_pts(struct path *path)
{
/* Find something mounted on "pts" in the same directory as
* the input path.
*/
struct dentry *parent = dget_parent(path->dentry);
struct dentry *child;
struct qstr this = QSTR_INIT("pts", 3);
if (unlikely(!path_connected(path->mnt, parent))) {
dput(parent);
return -ENOENT;
}
dput(path->dentry);
path->dentry = parent;
child = d_hash_and_lookup(parent, &this);
if (IS_ERR_OR_NULL(child))
return -ENOENT;
path->dentry = child;
dput(parent);
follow_down(path, 0);
return 0;
}
#endif
int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
struct path *path, int *empty)
{
struct filename *filename = getname_flags(name, flags, empty);
int ret = filename_lookup(dfd, filename, flags, path, NULL);
putname(filename);
return ret;
}
EXPORT_SYMBOL(user_path_at_empty);
int __check_sticky(struct mnt_idmap *idmap, struct inode *dir,
struct inode *inode)
{
kuid_t fsuid = current_fsuid();
if (vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode), fsuid))
return 0;
if (vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, dir), fsuid))
return 0;
return !capable_wrt_inode_uidgid(idmap, inode, CAP_FOWNER);
}
EXPORT_SYMBOL(__check_sticky);
/*
* Check whether we can remove a link victim from directory dir, check
* whether the type of victim is right.
* 1. We can't do it if dir is read-only (done in permission())
* 2. We should have write and exec permissions on dir
* 3. We can't remove anything from append-only dir
* 4. We can't do anything with immutable dir (done in permission())
* 5. If the sticky bit on dir is set we should either
* a. be owner of dir, or
* b. be owner of victim, or
* c. have CAP_FOWNER capability
* 6. If the victim is append-only or immutable we can't do antyhing with
* links pointing to it.
* 7. If the victim has an unknown uid or gid we can't change the inode.
* 8. If we were asked to remove a directory and victim isn't one - ENOTDIR.
* 9. If we were asked to remove a non-directory and victim isn't one - EISDIR.
* 10. We can't remove a root or mountpoint.
* 11. We don't allow removal of NFS sillyrenamed files; it's handled by
* nfs_async_unlink().
*/
static int may_delete(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *victim, bool isdir)
{
struct inode *inode = d_backing_inode(victim);
int error;
if (d_is_negative(victim))
return -ENOENT;
BUG_ON(!inode);
BUG_ON(victim->d_parent->d_inode != dir);
/* Inode writeback is not safe when the uid or gid are invalid. */
if (!vfsuid_valid(i_uid_into_vfsuid(idmap, inode)) ||
!vfsgid_valid(i_gid_into_vfsgid(idmap, inode)))
return -EOVERFLOW;
audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
error = inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
if (error)
return error;
if (IS_APPEND(dir))
return -EPERM;
if (check_sticky(idmap, dir, inode) || IS_APPEND(inode) ||
IS_IMMUTABLE(inode) || IS_SWAPFILE(inode) ||
HAS_UNMAPPED_ID(idmap, inode))
return -EPERM;
if (isdir) {
if (!d_is_dir(victim))
return -ENOTDIR;
if (IS_ROOT(victim))
return -EBUSY;
} else if (d_is_dir(victim))
return -EISDIR;
if (IS_DEADDIR(dir))
return -ENOENT;
if (victim->d_flags & DCACHE_NFSFS_RENAMED)
return -EBUSY;
return 0;
}
/* Check whether we can create an object with dentry child in directory
* dir.
* 1. We can't do it if child already exists (open has special treatment for
* this case, but since we are inlined it's OK)
* 2. We can't do it if dir is read-only (done in permission())
* 3. We can't do it if the fs can't represent the fsuid or fsgid.
* 4. We should have write and exec permissions on dir
* 5. We can't do it if dir is immutable (done in permission())
*/
static inline int may_create(struct mnt_idmap *idmap,
struct inode *dir, struct dentry *child)
{
audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
if (child->d_inode)
return -EEXIST;
if (IS_DEADDIR(dir))
return -ENOENT;
if (!fsuidgid_has_mapping(dir->i_sb, idmap))
return -EOVERFLOW;
return inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
}
static struct dentry *lock_two_directories(struct dentry *p1, struct dentry *p2)
{
struct dentry *p;
p = d_ancestor(p2, p1);
if (p) {
inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);
inode_lock_nested(p1->d_inode, I_MUTEX_CHILD);
return p;
}
p = d_ancestor(p1, p2);
if (p) {
inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);
inode_lock_nested(p2->d_inode, I_MUTEX_CHILD);
return p;
}
lock_two_inodes(p1->d_inode, p2->d_inode,
I_MUTEX_PARENT, I_MUTEX_PARENT2);
return NULL;
}
/*
* p1 and p2 should be directories on the same fs.
*/
struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)
{
if (p1 == p2) {
inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);
return NULL;
}
mutex_lock(&p1->d_sb->s_vfs_rename_mutex);
return lock_two_directories(p1, p2);
}
EXPORT_SYMBOL(lock_rename);
/*
* c1 and p2 should be on the same fs.
*/
struct dentry *lock_rename_child(struct dentry *c1, struct dentry *p2)
{
if (READ_ONCE(c1->d_parent) == p2) {
/*
* hopefully won't need to touch ->s_vfs_rename_mutex at all.
*/
inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);
/*
* now that p2 is locked, nobody can move in or out of it,
* so the test below is safe.
*/
if (likely(c1->d_parent == p2))
return NULL;
/*
* c1 got moved out of p2 while we'd been taking locks;
* unlock and fall back to slow case.
*/
inode_unlock(p2->d_inode);
}
mutex_lock(&c1->d_sb->s_vfs_rename_mutex);
/*
* nobody can move out of any directories on this fs.
*/
if (likely(c1->d_parent != p2))
return lock_two_directories(c1->d_parent, p2);
/*
* c1 got moved into p2 while we were taking locks;
* we need p2 locked and ->s_vfs_rename_mutex unlocked,
* for consistency with lock_rename().
*/
inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);
mutex_unlock(&c1->d_sb->s_vfs_rename_mutex);
return NULL;
}
EXPORT_SYMBOL(lock_rename_child);
void unlock_rename(struct dentry *p1, struct dentry *p2)
{
inode_unlock(p1->d_inode);
if (p1 != p2) {
inode_unlock(p2->d_inode);
mutex_unlock(&p1->d_sb->s_vfs_rename_mutex);
}
}
EXPORT_SYMBOL(unlock_rename);
/**
* mode_strip_umask - handle vfs umask stripping
* @dir: parent directory of the new inode
* @mode: mode of the new inode to be created in @dir
*
* Umask stripping depends on whether or not the filesystem supports POSIX
* ACLs. If the filesystem doesn't support it umask stripping is done directly
* in here. If the filesystem does support POSIX ACLs umask stripping is
* deferred until the filesystem calls posix_acl_create().
*
* Returns: mode
*/
static inline umode_t mode_strip_umask(const struct inode *dir, umode_t mode)
{
if (!IS_POSIXACL(dir))
mode &= ~current_umask();
return mode;
}
/**
* vfs_prepare_mode - prepare the mode to be used for a new inode
* @idmap: idmap of the mount the inode was found from
* @dir: parent directory of the new inode
* @mode: mode of the new inode
* @mask_perms: allowed permission by the vfs
* @type: type of file to be created
*
* This helper consolidates and enforces vfs restrictions on the @mode of a new
* object to be created.
*
* Umask stripping depends on whether the filesystem supports POSIX ACLs (see
* the kernel documentation for mode_strip_umask()). Moving umask stripping
* after setgid stripping allows the same ordering for both non-POSIX ACL and
* POSIX ACL supporting filesystems.
*
* Note that it's currently valid for @type to be 0 if a directory is created.
* Filesystems raise that flag individually and we need to check whether each
* filesystem can deal with receiving S_IFDIR from the vfs before we enforce a
* non-zero type.
*
* Returns: mode to be passed to the filesystem
*/
static inline umode_t vfs_prepare_mode(struct mnt_idmap *idmap,
const struct inode *dir, umode_t mode,
umode_t mask_perms, umode_t type)
{
mode = mode_strip_sgid(idmap, dir, mode);
mode = mode_strip_umask(dir, mode);
/*
* Apply the vfs mandated allowed permission mask and set the type of
* file to be created before we call into the filesystem.
*/
mode &= (mask_perms & ~S_IFMT);
mode |= (type & S_IFMT);
return mode;
}
/**
* vfs_create - create new file
* @idmap: idmap of the mount the inode was found from
* @dir: inode of @dentry
* @dentry: pointer to dentry of the base directory
* @mode: mode of the new file
* @want_excl: whether the file must not yet exist
*
* Create a new file.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int vfs_create(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, bool want_excl)
{
int error;
error = may_create(idmap, dir, dentry);
if (error)
return error;
if (!dir->i_op->create)
return -EACCES; /* shouldn't it be ENOSYS? */
mode = vfs_prepare_mode(idmap, dir, mode, S_IALLUGO, S_IFREG);
error = security_inode_create(dir, dentry, mode);
if (error)
return error;
error = dir->i_op->create(idmap, dir, dentry, mode, want_excl);
if (!error)
fsnotify_create(dir, dentry);
return error;
}
EXPORT_SYMBOL(vfs_create);
int vfs_mkobj(struct dentry *dentry, umode_t mode,
int (*f)(struct dentry *, umode_t, void *),
void *arg)
{
struct inode *dir = dentry->d_parent->d_inode;
int error = may_create(&nop_mnt_idmap, dir, dentry);
if (error)
return error;
mode &= S_IALLUGO;
mode |= S_IFREG;
error = security_inode_create(dir, dentry, mode);
if (error)
return error;
error = f(dentry, mode, arg);
if (!error)
fsnotify_create(dir, dentry);
return error;
}
EXPORT_SYMBOL(vfs_mkobj);
bool may_open_dev(const struct path *path)
{
return !(path->mnt->mnt_flags & MNT_NODEV) &&
!(path->mnt->mnt_sb->s_iflags & SB_I_NODEV);
}
static int may_open(struct mnt_idmap *idmap, const struct path *path,
int acc_mode, int flag)
{
struct dentry *dentry = path->dentry;
struct inode *inode = dentry->d_inode;
int error;
if (!inode)
return -ENOENT;
switch (inode->i_mode & S_IFMT) {
case S_IFLNK:
return -ELOOP;
case S_IFDIR:
if (acc_mode & MAY_WRITE)
return -EISDIR;
if (acc_mode & MAY_EXEC)
return -EACCES;
break;
case S_IFBLK:
case S_IFCHR:
if (!may_open_dev(path))
return -EACCES;
fallthrough;
case S_IFIFO:
case S_IFSOCK:
if (acc_mode & MAY_EXEC)
return -EACCES;
flag &= ~O_TRUNC;
break;
case S_IFREG:
if ((acc_mode & MAY_EXEC) && path_noexec(path))
return -EACCES;
break;
}
error = inode_permission(idmap, inode, MAY_OPEN | acc_mode);
if (error)
return error;
/*
* An append-only file must be opened in append mode for writing.
*/
if (IS_APPEND(inode)) {
if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND))
return -EPERM;
if (flag & O_TRUNC)
return -EPERM;
}
/* O_NOATIME can only be set by the owner or superuser */
if (flag & O_NOATIME && !inode_owner_or_capable(idmap, inode))
return -EPERM;
return 0;
}
static int handle_truncate(struct mnt_idmap *idmap, struct file *filp)
{
const struct path *path = &filp->f_path;
struct inode *inode = path->dentry->d_inode;
int error = get_write_access(inode);
if (error)
return error;
error = security_file_truncate(filp);
if (!error) {
error = do_truncate(idmap, path->dentry, 0,
ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
filp);
}
put_write_access(inode);
return error;
}
static inline int open_to_namei_flags(int flag)
{
if ((flag & O_ACCMODE) == 3)
flag--;
return flag;
}
static int may_o_create(struct mnt_idmap *idmap,
const struct path *dir, struct dentry *dentry,
umode_t mode)
{
int error = security_path_mknod(dir, dentry, mode, 0);
if (error)
return error;
if (!fsuidgid_has_mapping(dir->dentry->d_sb, idmap))
return -EOVERFLOW;
error = inode_permission(idmap, dir->dentry->d_inode,
MAY_WRITE | MAY_EXEC);
if (error)
return error;
return security_inode_create(dir->dentry->d_inode, dentry, mode);
}
/*
* Attempt to atomically look up, create and open a file from a negative
* dentry.
*
* Returns 0 if successful. The file will have been created and attached to
* @file by the filesystem calling finish_open().
*
* If the file was looked up only or didn't need creating, FMODE_OPENED won't
* be set. The caller will need to perform the open themselves. @path will
* have been updated to point to the new dentry. This may be negative.
*
* Returns an error code otherwise.
*/
static struct dentry *atomic_open(struct nameidata *nd, struct dentry *dentry,
struct file *file,
int open_flag, umode_t mode)
{
struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
struct inode *dir = nd->path.dentry->d_inode;
int error;
if (nd->flags & LOOKUP_DIRECTORY)
open_flag |= O_DIRECTORY;
file->f_path.dentry = DENTRY_NOT_SET;
file->f_path.mnt = nd->path.mnt;
error = dir->i_op->atomic_open(dir, dentry, file,
open_to_namei_flags(open_flag), mode);
d_lookup_done(dentry);
if (!error) {
if (file->f_mode & FMODE_OPENED) {
if (unlikely(dentry != file->f_path.dentry)) {
dput(dentry);
dentry = dget(file->f_path.dentry);
}
} else if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) {
error = -EIO;
} else {
if (file->f_path.dentry) {
dput(dentry);
dentry = file->f_path.dentry;
}
if (unlikely(d_is_negative(dentry)))
error = -ENOENT;
}
}
if (error) {
dput(dentry);
dentry = ERR_PTR(error);
}
return dentry;
}
/*
* Look up and maybe create and open the last component.
*
* Must be called with parent locked (exclusive in O_CREAT case).
*
* Returns 0 on success, that is, if
* the file was successfully atomically created (if necessary) and opened, or
* the file was not completely opened at this time, though lookups and
* creations were performed.
* These case are distinguished by presence of FMODE_OPENED on file->f_mode.
* In the latter case dentry returned in @path might be negative if O_CREAT
* hadn't been specified.
*
* An error code is returned on failure.
*/
static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
const struct open_flags *op,
bool got_write)
{
struct mnt_idmap *idmap;
struct dentry *dir = nd->path.dentry;
struct inode *dir_inode = dir->d_inode;
int open_flag = op->open_flag;
struct dentry *dentry;
int error, create_error = 0;
umode_t mode = op->mode;
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
if (unlikely(IS_DEADDIR(dir_inode)))
return ERR_PTR(-ENOENT);
file->f_mode &= ~FMODE_CREATED;
dentry = d_lookup(dir, &nd->last);
for (;;) {
if (!dentry) {
dentry = d_alloc_parallel(dir, &nd->last, &wq);
if (IS_ERR(dentry))
return dentry;
}
if (d_in_lookup(dentry))
break;
error = d_revalidate(dentry, nd->flags);
if (likely(error > 0))
break;
if (error)
goto out_dput;
d_invalidate(dentry);
dput(dentry);
dentry = NULL;
}
if (dentry->d_inode) {
/* Cached positive dentry: will open in f_op->open */
return dentry;
}
/*
* Checking write permission is tricky, bacuse we don't know if we are
* going to actually need it: O_CREAT opens should work as long as the
* file exists. But checking existence breaks atomicity. The trick is
* to check access and if not granted clear O_CREAT from the flags.
*
* Another problem is returing the "right" error value (e.g. for an
* O_EXCL open we want to return EEXIST not EROFS).
*/
if (unlikely(!got_write))
open_flag &= ~O_TRUNC;
idmap = mnt_idmap(nd->path.mnt);
if (open_flag & O_CREAT) {
if (open_flag & O_EXCL)
open_flag &= ~O_TRUNC;
mode = vfs_prepare_mode(idmap, dir->d_inode, mode, mode, mode);
if (likely(got_write))
create_error = may_o_create(idmap, &nd->path,
dentry, mode);
else
create_error = -EROFS;
}
if (create_error)
open_flag &= ~O_CREAT;
if (dir_inode->i_op->atomic_open) {
dentry = atomic_open(nd, dentry, file, open_flag, mode);
if (unlikely(create_error) && dentry == ERR_PTR(-ENOENT))
dentry = ERR_PTR(create_error);
return dentry;
}
if (d_in_lookup(dentry)) {
struct dentry *res = dir_inode->i_op->lookup(dir_inode, dentry,
nd->flags);
d_lookup_done(dentry);
if (unlikely(res)) {
if (IS_ERR(res)) {
error = PTR_ERR(res);
goto out_dput;
}
dput(dentry);
dentry = res;
}
}
/* Negative dentry, just create the file */
if (!dentry->d_inode && (open_flag & O_CREAT)) {
file->f_mode |= FMODE_CREATED;
audit_inode_child(dir_inode, dentry, AUDIT_TYPE_CHILD_CREATE);
if (!dir_inode->i_op->create) {
error = -EACCES;
goto out_dput;
}
error = dir_inode->i_op->create(idmap, dir_inode, dentry,
mode, open_flag & O_EXCL);
if (error)
goto out_dput;
}
if (unlikely(create_error) && !dentry->d_inode) {
error = create_error;
goto out_dput;
}
return dentry;
out_dput:
dput(dentry);
return ERR_PTR(error);
}
static const char *open_last_lookups(struct nameidata *nd,
struct file *file, const struct open_flags *op)
{
struct dentry *dir = nd->path.dentry;
int open_flag = op->open_flag;
bool got_write = false;
struct dentry *dentry;
const char *res;
nd->flags |= op->intent;
if (nd->last_type != LAST_NORM) {
if (nd->depth)
put_link(nd);
return handle_dots(nd, nd->last_type);
}
if (!(open_flag & O_CREAT)) {
if (nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
/* we _can_ be in RCU mode here */
dentry = lookup_fast(nd);
if (IS_ERR(dentry))
return ERR_CAST(dentry);
if (likely(dentry))
goto finish_lookup;
BUG_ON(nd->flags & LOOKUP_RCU);
} else {
/* create side of things */
if (nd->flags & LOOKUP_RCU) {
if (!try_to_unlazy(nd))
return ERR_PTR(-ECHILD);
}
audit_inode(nd->name, dir, AUDIT_INODE_PARENT);
/* trailing slashes? */
if (unlikely(nd->last.name[nd->last.len]))
return ERR_PTR(-EISDIR);
}
if (open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) {
got_write = !mnt_want_write(nd->path.mnt);
/*
* do _not_ fail yet - we might not need that or fail with
* a different error; let lookup_open() decide; we'll be
* dropping this one anyway.
*/
}
if (open_flag & O_CREAT)
inode_lock(dir->d_inode);
else
inode_lock_shared(dir->d_inode);
dentry = lookup_open(nd, file, op, got_write);
if (!IS_ERR(dentry) && (file->f_mode & FMODE_CREATED))
fsnotify_create(dir->d_inode, dentry);
if (open_flag & O_CREAT)
inode_unlock(dir->d_inode);
else
inode_unlock_shared(dir->d_inode);
if (got_write)
mnt_drop_write(nd->path.mnt);
if (IS_ERR(dentry))
return ERR_CAST(dentry);
if (file->f_mode & (FMODE_OPENED | FMODE_CREATED)) {
dput(nd->path.dentry);
nd->path.dentry = dentry;
return NULL;
}
finish_lookup:
if (nd->depth)
put_link(nd);
res = step_into(nd, WALK_TRAILING, dentry);
if (unlikely(res))
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
return res;
}
/*
* Handle the last step of open()
*/
static int do_open(struct nameidata *nd,
struct file *file, const struct open_flags *op)
{
struct mnt_idmap *idmap;
int open_flag = op->open_flag;
bool do_truncate;
int acc_mode;
int error;
if (!(file->f_mode & (FMODE_OPENED | FMODE_CREATED))) {
error = complete_walk(nd);
if (error)
return error;
}
if (!(file->f_mode & FMODE_CREATED))
audit_inode(nd->name, nd->path.dentry, 0);
idmap = mnt_idmap(nd->path.mnt);
if (open_flag & O_CREAT) {
if ((open_flag & O_EXCL) && !(file->f_mode & FMODE_CREATED))
return -EEXIST;
if (d_is_dir(nd->path.dentry))
return -EISDIR;
error = may_create_in_sticky(idmap, nd,
d_backing_inode(nd->path.dentry));
if (unlikely(error))
return error;
}
if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
return -ENOTDIR;
do_truncate = false;
acc_mode = op->acc_mode;
if (file->f_mode & FMODE_CREATED) {
/* Don't check for write permission, don't truncate */
open_flag &= ~O_TRUNC;
acc_mode = 0;
} else if (d_is_reg(nd->path.dentry) && open_flag & O_TRUNC) {
error = mnt_want_write(nd->path.mnt);
if (error)
return error;
do_truncate = true;
}
error = may_open(idmap, &nd->path, acc_mode, open_flag);
if (!error && !(file->f_mode & FMODE_OPENED))
error = vfs_open(&nd->path, file);
if (!error)
error = ima_file_check(file, op->acc_mode);
if (!error && do_truncate)
error = handle_truncate(idmap, file);
if (unlikely(error > 0)) {
WARN_ON(1);
error = -EINVAL;
}
if (do_truncate)
mnt_drop_write(nd->path.mnt);
return error;
}
/**
* vfs_tmpfile - create tmpfile
* @idmap: idmap of the mount the inode was found from
* @parentpath: pointer to the path of the base directory
* @file: file descriptor of the new tmpfile
* @mode: mode of the new tmpfile
*
* Create a temporary file.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
static int vfs_tmpfile(struct mnt_idmap *idmap,
const struct path *parentpath,
struct file *file, umode_t mode)
{
struct dentry *child;
struct inode *dir = d_inode(parentpath->dentry);
struct inode *inode;
int error;
int open_flag = file->f_flags;
/* we want directory to be writable */
error = inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
if (error)
return error;
if (!dir->i_op->tmpfile)
return -EOPNOTSUPP;
child = d_alloc(parentpath->dentry, &slash_name);
if (unlikely(!child))
return -ENOMEM;
file->f_path.mnt = parentpath->mnt;
file->f_path.dentry = child;
mode = vfs_prepare_mode(idmap, dir, mode, mode, mode);
error = dir->i_op->tmpfile(idmap, dir, file, mode);
dput(child);
if (error)
return error;
/* Don't check for other permissions, the inode was just created */
error = may_open(idmap, &file->f_path, 0, file->f_flags);
if (error)
return error;
inode = file_inode(file);
if (!(open_flag & O_EXCL)) {
spin_lock(&inode->i_lock);
inode->i_state |= I_LINKABLE;
spin_unlock(&inode->i_lock);
}
ima_post_create_tmpfile(idmap, inode);
return 0;
}
/**
* kernel_tmpfile_open - open a tmpfile for kernel internal use
* @idmap: idmap of the mount the inode was found from
* @parentpath: path of the base directory
* @mode: mode of the new tmpfile
* @open_flag: flags
* @cred: credentials for open
*
* Create and open a temporary file. The file is not accounted in nr_files,
* hence this is only for kernel internal use, and must not be installed into
* file tables or such.
*/
struct file *kernel_tmpfile_open(struct mnt_idmap *idmap,
const struct path *parentpath,
umode_t mode, int open_flag,
const struct cred *cred)
{
struct file *file;
int error;
file = alloc_empty_file_noaccount(open_flag, cred);
if (IS_ERR(file))
return file;
error = vfs_tmpfile(idmap, parentpath, file, mode);
if (error) {
fput(file);
file = ERR_PTR(error);
}
return file;
}
EXPORT_SYMBOL(kernel_tmpfile_open);
static int do_tmpfile(struct nameidata *nd, unsigned flags,
const struct open_flags *op,
struct file *file)
{
struct path path;
int error = path_lookupat(nd, flags | LOOKUP_DIRECTORY, &path);
if (unlikely(error))
return error;
error = mnt_want_write(path.mnt);
if (unlikely(error))
goto out;
error = vfs_tmpfile(mnt_idmap(path.mnt), &path, file, op->mode);
if (error)
goto out2;
audit_inode(nd->name, file->f_path.dentry, 0);
out2:
mnt_drop_write(path.mnt);
out:
path_put(&path);
return error;
}
static int do_o_path(struct nameidata *nd, unsigned flags, struct file *file)
{
struct path path;
int error = path_lookupat(nd, flags, &path);
if (!error) {
audit_inode(nd->name, path.dentry, 0);
error = vfs_open(&path, file);
path_put(&path);
}
return error;
}
static struct file *path_openat(struct nameidata *nd,
const struct open_flags *op, unsigned flags)
{
struct file *file;
int error;
file = alloc_empty_file(op->open_flag, current_cred());
if (IS_ERR(file))
return file;
if (unlikely(file->f_flags & __O_TMPFILE)) {
error = do_tmpfile(nd, flags, op, file);
} else if (unlikely(file->f_flags & O_PATH)) {
error = do_o_path(nd, flags, file);
} else {
const char *s = path_init(nd, flags);
while (!(error = link_path_walk(s, nd)) &&
(s = open_last_lookups(nd, file, op)) != NULL)
;
if (!error)
error = do_open(nd, file, op);
terminate_walk(nd);
}
if (likely(!error)) {
if (likely(file->f_mode & FMODE_OPENED))
return file;
WARN_ON(1);
error = -EINVAL;
}
fput(file);
if (error == -EOPENSTALE) {
if (flags & LOOKUP_RCU)
error = -ECHILD;
else
error = -ESTALE;
}
return ERR_PTR(error);
}
struct file *do_filp_open(int dfd, struct filename *pathname,
const struct open_flags *op)
{
struct nameidata nd;
int flags = op->lookup_flags;
struct file *filp;
set_nameidata(&nd, dfd, pathname, NULL);
filp = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(filp == ERR_PTR(-ECHILD)))
filp = path_openat(&nd, op, flags);
if (unlikely(filp == ERR_PTR(-ESTALE)))
filp = path_openat(&nd, op, flags | LOOKUP_REVAL);
restore_nameidata();
return filp;
}
struct file *do_file_open_root(const struct path *root,
const char *name, const struct open_flags *op)
{
struct nameidata nd;
struct file *file;
struct filename *filename;
int flags = op->lookup_flags;
if (d_is_symlink(root->dentry) && op->intent & LOOKUP_OPEN)
return ERR_PTR(-ELOOP);
filename = getname_kernel(name);
if (IS_ERR(filename))
return ERR_CAST(filename);
set_nameidata(&nd, -1, filename, root);
file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
file = path_openat(&nd, op, flags);
if (unlikely(file == ERR_PTR(-ESTALE)))
file = path_openat(&nd, op, flags | LOOKUP_REVAL);
restore_nameidata();
putname(filename);
return file;
}
static struct dentry *filename_create(int dfd, struct filename *name,
struct path *path, unsigned int lookup_flags)
{
struct dentry *dentry = ERR_PTR(-EEXIST);
struct qstr last;
bool want_dir = lookup_flags & LOOKUP_DIRECTORY;
unsigned int reval_flag = lookup_flags & LOOKUP_REVAL;
unsigned int create_flags = LOOKUP_CREATE | LOOKUP_EXCL;
int type;
int err2;
int error;
error = filename_parentat(dfd, name, reval_flag, path, &last, &type);
if (error)
return ERR_PTR(error);
/*
* Yucky last component or no last component at all?
* (foo/., foo/.., /////)
*/
if (unlikely(type != LAST_NORM))
goto out;
/* don't fail immediately if it's r/o, at least try to report other errors */
err2 = mnt_want_write(path->mnt);
/*
* Do the final lookup. Suppress 'create' if there is a trailing
* '/', and a directory wasn't requested.
*/
if (last.name[last.len] && !want_dir)
create_flags = 0;
inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
dentry = lookup_one_qstr_excl(&last, path->dentry,
reval_flag | create_flags);
if (IS_ERR(dentry))
goto unlock;
error = -EEXIST;
if (d_is_positive(dentry))
goto fail;
/*
* Special case - lookup gave negative, but... we had foo/bar/
* From the vfs_mknod() POV we just have a negative dentry -
* all is fine. Let's be bastards - you had / on the end, you've
* been asking for (non-existent) directory. -ENOENT for you.
*/
if (unlikely(!create_flags)) {
error = -ENOENT;
goto fail;
}
if (unlikely(err2)) {
error = err2;
goto fail;
}
return dentry;
fail:
dput(dentry);
dentry = ERR_PTR(error);
unlock:
inode_unlock(path->dentry->d_inode);
if (!err2)
mnt_drop_write(path->mnt);
out:
path_put(path);
return dentry;
}
struct dentry *kern_path_create(int dfd, const char *pathname,
struct path *path, unsigned int lookup_flags)
{
struct filename *filename = getname_kernel(pathname);
struct dentry *res = filename_create(dfd, filename, path, lookup_flags);
putname(filename);
return res;
}
EXPORT_SYMBOL(kern_path_create);
void done_path_create(struct path *path, struct dentry *dentry)
{
dput(dentry);
inode_unlock(path->dentry->d_inode);
mnt_drop_write(path->mnt);
path_put(path);
}
EXPORT_SYMBOL(done_path_create);
inline struct dentry *user_path_create(int dfd, const char __user *pathname,
struct path *path, unsigned int lookup_flags)
{
struct filename *filename = getname(pathname);
struct dentry *res = filename_create(dfd, filename, path, lookup_flags);
putname(filename);
return res;
}
EXPORT_SYMBOL(user_path_create);
/**
* vfs_mknod - create device node or file
* @idmap: idmap of the mount the inode was found from
* @dir: inode of @dentry
* @dentry: pointer to dentry of the base directory
* @mode: mode of the new device node or file
* @dev: device number of device to create
*
* Create a device node or file.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, dev_t dev)
{
bool is_whiteout = S_ISCHR(mode) && dev == WHITEOUT_DEV;
int error = may_create(idmap, dir, dentry);
if (error)
return error;
if ((S_ISCHR(mode) || S_ISBLK(mode)) && !is_whiteout &&
!capable(CAP_MKNOD))
return -EPERM;
if (!dir->i_op->mknod)
return -EPERM;
mode = vfs_prepare_mode(idmap, dir, mode, mode, mode);
error = devcgroup_inode_mknod(mode, dev);
if (error)
return error;
error = security_inode_mknod(dir, dentry, mode, dev);
if (error)
return error;
error = dir->i_op->mknod(idmap, dir, dentry, mode, dev);
if (!error)
fsnotify_create(dir, dentry);
return error;
}
EXPORT_SYMBOL(vfs_mknod);
static int may_mknod(umode_t mode)
{
switch (mode & S_IFMT) {
case S_IFREG:
case S_IFCHR:
case S_IFBLK:
case S_IFIFO:
case S_IFSOCK:
case 0: /* zero mode translates to S_IFREG */
return 0;
case S_IFDIR:
return -EPERM;
default:
return -EINVAL;
}
}
static int do_mknodat(int dfd, struct filename *name, umode_t mode,
unsigned int dev)
{
struct mnt_idmap *idmap;
struct dentry *dentry;
struct path path;
int error;
unsigned int lookup_flags = 0;
error = may_mknod(mode);
if (error)
goto out1;
retry:
dentry = filename_create(dfd, name, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out1;
error = security_path_mknod(&path, dentry,
mode_strip_umask(path.dentry->d_inode, mode), dev);
if (error)
goto out2;
idmap = mnt_idmap(path.mnt);
switch (mode & S_IFMT) {
case 0: case S_IFREG:
error = vfs_create(idmap, path.dentry->d_inode,
dentry, mode, true);
if (!error)
ima_post_path_mknod(idmap, dentry);
break;
case S_IFCHR: case S_IFBLK:
error = vfs_mknod(idmap, path.dentry->d_inode,
dentry, mode, new_decode_dev(dev));
break;
case S_IFIFO: case S_IFSOCK:
error = vfs_mknod(idmap, path.dentry->d_inode,
dentry, mode, 0);
break;
}
out2:
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out1:
putname(name);
return error;
}
SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
unsigned int, dev)
{
return do_mknodat(dfd, getname(filename), mode, dev);
}
SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev)
{
return do_mknodat(AT_FDCWD, getname(filename), mode, dev);
}
/**
* vfs_mkdir - create directory
* @idmap: idmap of the mount the inode was found from
* @dir: inode of @dentry
* @dentry: pointer to dentry of the base directory
* @mode: mode of the new directory
*
* Create a directory.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode)
{
int error;
unsigned max_links = dir->i_sb->s_max_links;
error = may_create(idmap, dir, dentry);
if (error)
return error;
if (!dir->i_op->mkdir)
return -EPERM;
mode = vfs_prepare_mode(idmap, dir, mode, S_IRWXUGO | S_ISVTX, 0);
error = security_inode_mkdir(dir, dentry, mode);
if (error)
return error;
if (max_links && dir->i_nlink >= max_links)
return -EMLINK;
error = dir->i_op->mkdir(idmap, dir, dentry, mode);
if (!error)
fsnotify_mkdir(dir, dentry);
return error;
}
EXPORT_SYMBOL(vfs_mkdir);
int do_mkdirat(int dfd, struct filename *name, umode_t mode)
{
struct dentry *dentry;
struct path path;
int error;
unsigned int lookup_flags = LOOKUP_DIRECTORY;
retry:
dentry = filename_create(dfd, name, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_putname;
error = security_path_mkdir(&path, dentry,
mode_strip_umask(path.dentry->d_inode, mode));
if (!error) {
error = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode,
dentry, mode);
}
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out_putname:
putname(name);
return error;
}
SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
{
return do_mkdirat(dfd, getname(pathname), mode);
}
SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
{
return do_mkdirat(AT_FDCWD, getname(pathname), mode);
}
/**
* vfs_rmdir - remove directory
* @idmap: idmap of the mount the inode was found from
* @dir: inode of @dentry
* @dentry: pointer to dentry of the base directory
*
* Remove a directory.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int vfs_rmdir(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry)
{
int error = may_delete(idmap, dir, dentry, 1);
if (error)
return error;
if (!dir->i_op->rmdir)
return -EPERM;
dget(dentry);
inode_lock(dentry->d_inode);
error = -EBUSY;
if (is_local_mountpoint(dentry) ||
(dentry->d_inode->i_flags & S_KERNEL_FILE))
goto out;
error = security_inode_rmdir(dir, dentry);
if (error)
goto out;
error = dir->i_op->rmdir(dir, dentry);
if (error)
goto out;
shrink_dcache_parent(dentry);
dentry->d_inode->i_flags |= S_DEAD;
dont_mount(dentry);
detach_mounts(dentry);
out:
inode_unlock(dentry->d_inode);
dput(dentry);
if (!error)
d_delete_notify(dir, dentry);
return error;
}
EXPORT_SYMBOL(vfs_rmdir);
int do_rmdir(int dfd, struct filename *name)
{
int error;
struct dentry *dentry;
struct path path;
struct qstr last;
int type;
unsigned int lookup_flags = 0;
retry:
error = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
if (error)
goto exit1;
switch (type) {
case LAST_DOTDOT:
error = -ENOTEMPTY;
goto exit2;
case LAST_DOT:
error = -EINVAL;
goto exit2;
case LAST_ROOT:
error = -EBUSY;
goto exit2;
}
error = mnt_want_write(path.mnt);
if (error)
goto exit2;
inode_lock_nested(path.dentry->d_inode, I_MUTEX_PARENT);
dentry = lookup_one_qstr_excl(&last, path.dentry, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto exit3;
if (!dentry->d_inode) {
error = -ENOENT;
goto exit4;
}
error = security_path_rmdir(&path, dentry);
if (error)
goto exit4;
error = vfs_rmdir(mnt_idmap(path.mnt), path.dentry->d_inode, dentry);
exit4:
dput(dentry);
exit3:
inode_unlock(path.dentry->d_inode);
mnt_drop_write(path.mnt);
exit2:
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
exit1:
putname(name);
return error;
}
SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
{
return do_rmdir(AT_FDCWD, getname(pathname));
}
/**
* vfs_unlink - unlink a filesystem object
* @idmap: idmap of the mount the inode was found from
* @dir: parent directory
* @dentry: victim
* @delegated_inode: returns victim inode, if the inode is delegated.
*
* The caller must hold dir->i_mutex.
*
* If vfs_unlink discovers a delegation, it will return -EWOULDBLOCK and
* return a reference to the inode in delegated_inode. The caller
* should then break the delegation on that inode and retry. Because
* breaking a delegation may take a long time, the caller should drop
* dir->i_mutex before doing so.
*
* Alternatively, a caller may pass NULL for delegated_inode. This may
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int vfs_unlink(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, struct inode **delegated_inode)
{
struct inode *target = dentry->d_inode;
int error = may_delete(idmap, dir, dentry, 0);
if (error)
return error;
if (!dir->i_op->unlink)
return -EPERM;
inode_lock(target);
if (IS_SWAPFILE(target))
error = -EPERM;
else if (is_local_mountpoint(dentry))
error = -EBUSY;
else {
error = security_inode_unlink(dir, dentry);
if (!error) {
error = try_break_deleg(target, delegated_inode);
if (error)
goto out;
error = dir->i_op->unlink(dir, dentry);
if (!error) {
dont_mount(dentry);
detach_mounts(dentry);
}
}
}
out:
inode_unlock(target);
/* We don't d_delete() NFS sillyrenamed files--they still exist. */
if (!error && dentry->d_flags & DCACHE_NFSFS_RENAMED) {
fsnotify_unlink(dir, dentry);
} else if (!error) {
fsnotify_link_count(target);
d_delete_notify(dir, dentry);
}
return error;
}
EXPORT_SYMBOL(vfs_unlink);
/*
* Make sure that the actual truncation of the file will occur outside its
* directory's i_mutex. Truncate can take a long time if there is a lot of
* writeout happening, and we don't want to prevent access to the directory
* while waiting on the I/O.
*/
int do_unlinkat(int dfd, struct filename *name)
{
int error;
struct dentry *dentry;
struct path path;
struct qstr last;
int type;
struct inode *inode = NULL;
struct inode *delegated_inode = NULL;
unsigned int lookup_flags = 0;
retry:
error = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
if (error)
goto exit1;
error = -EISDIR;
if (type != LAST_NORM)
goto exit2;
error = mnt_want_write(path.mnt);
if (error)
goto exit2;
retry_deleg:
inode_lock_nested(path.dentry->d_inode, I_MUTEX_PARENT);
dentry = lookup_one_qstr_excl(&last, path.dentry, lookup_flags);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
/* Why not before? Because we want correct error value */
if (last.name[last.len])
goto slashes;
inode = dentry->d_inode;
if (d_is_negative(dentry))
goto slashes;
ihold(inode);
error = security_path_unlink(&path, dentry);
if (error)
goto exit3;
error = vfs_unlink(mnt_idmap(path.mnt), path.dentry->d_inode,
dentry, &delegated_inode);
exit3:
dput(dentry);
}
inode_unlock(path.dentry->d_inode);
if (inode)
iput(inode); /* truncate the inode here */
inode = NULL;
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
mnt_drop_write(path.mnt);
exit2:
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
inode = NULL;
goto retry;
}
exit1:
putname(name);
return error;
slashes:
if (d_is_negative(dentry))
error = -ENOENT;
else if (d_is_dir(dentry))
error = -EISDIR;
else
error = -ENOTDIR;
goto exit3;
}
SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
{
if ((flag & ~AT_REMOVEDIR) != 0)
return -EINVAL;
if (flag & AT_REMOVEDIR)
return do_rmdir(dfd, getname(pathname));
return do_unlinkat(dfd, getname(pathname));
}
SYSCALL_DEFINE1(unlink, const char __user *, pathname)
{
return do_unlinkat(AT_FDCWD, getname(pathname));
}
/**
* vfs_symlink - create symlink
* @idmap: idmap of the mount the inode was found from
* @dir: inode of @dentry
* @dentry: pointer to dentry of the base directory
* @oldname: name of the file to link to
*
* Create a symlink.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, const char *oldname)
{
int error;
error = may_create(idmap, dir, dentry);
if (error)
return error;
if (!dir->i_op->symlink)
return -EPERM;
error = security_inode_symlink(dir, dentry, oldname);
if (error)
return error;
error = dir->i_op->symlink(idmap, dir, dentry, oldname);
if (!error)
fsnotify_create(dir, dentry);
return error;
}
EXPORT_SYMBOL(vfs_symlink);
int do_symlinkat(struct filename *from, int newdfd, struct filename *to)
{
int error;
struct dentry *dentry;
struct path path;
unsigned int lookup_flags = 0;
if (IS_ERR(from)) {
error = PTR_ERR(from);
goto out_putnames;
}
retry:
dentry = filename_create(newdfd, to, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_putnames;
error = security_path_symlink(&path, dentry, from->name);
if (!error)
error = vfs_symlink(mnt_idmap(path.mnt), path.dentry->d_inode,
dentry, from->name);
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out_putnames:
putname(to);
putname(from);
return error;
}
SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
return do_symlinkat(getname(oldname), newdfd, getname(newname));
}
SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
{
return do_symlinkat(getname(oldname), AT_FDCWD, getname(newname));
}
/**
* vfs_link - create a new link
* @old_dentry: object to be linked
* @idmap: idmap of the mount
* @dir: new parent
* @new_dentry: where to create the new link
* @delegated_inode: returns inode needing a delegation break
*
* The caller must hold dir->i_mutex
*
* If vfs_link discovers a delegation on the to-be-linked file in need
* of breaking, it will return -EWOULDBLOCK and return a reference to the
* inode in delegated_inode. The caller should then break the delegation
* and retry. Because breaking a delegation may take a long time, the
* caller should drop the i_mutex before doing so.
*
* Alternatively, a caller may pass NULL for delegated_inode. This may
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then take
* care to map the inode according to @idmap before checking permissions.
* On non-idmapped mounts or if permission checking is to be performed on the
* raw inode simply passs @nop_mnt_idmap.
*/
int vfs_link(struct dentry *old_dentry, struct mnt_idmap *idmap,
struct inode *dir, struct dentry *new_dentry,
struct inode **delegated_inode)
{
struct inode *inode = old_dentry->d_inode;
unsigned max_links = dir->i_sb->s_max_links;
int error;
if (!inode)
return -ENOENT;
error = may_create(idmap, dir, new_dentry);
if (error)
return error;
if (dir->i_sb != inode->i_sb)
return -EXDEV;
/*
* A link to an append-only or immutable file cannot be created.
*/
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return -EPERM;
/*
* Updating the link count will likely cause i_uid and i_gid to
* be writen back improperly if their true value is unknown to
* the vfs.
*/
if (HAS_UNMAPPED_ID(idmap, inode))
return -EPERM;
if (!dir->i_op->link)
return -EPERM;
if (S_ISDIR(inode->i_mode))
return -EPERM;
error = security_inode_link(old_dentry, dir, new_dentry);
if (error)
return error;
inode_lock(inode);
/* Make sure we don't allow creating hardlink to an unlinked file */
if (inode->i_nlink == 0 && !(inode->i_state & I_LINKABLE))
error = -ENOENT;
else if (max_links && inode->i_nlink >= max_links)
error = -EMLINK;
else {
error = try_break_deleg(inode, delegated_inode);
if (!error)
error = dir->i_op->link(old_dentry, dir, new_dentry);
}
if (!error && (inode->i_state & I_LINKABLE)) {
spin_lock(&inode->i_lock);
inode->i_state &= ~I_LINKABLE;
spin_unlock(&inode->i_lock);
}
inode_unlock(inode);
if (!error)
fsnotify_link(dir, inode, new_dentry);
return error;
}
EXPORT_SYMBOL(vfs_link);
/*
* Hardlinks are often used in delicate situations. We avoid
* security-related surprises by not following symlinks on the
* newname. --KAB
*
* We don't follow them on the oldname either to be compatible
* with linux 2.0, and to avoid hard-linking to directories
* and other special files. --ADM
*/
int do_linkat(int olddfd, struct filename *old, int newdfd,
struct filename *new, int flags)
{
struct mnt_idmap *idmap;
struct dentry *new_dentry;
struct path old_path, new_path;
struct inode *delegated_inode = NULL;
int how = 0;
int error;
if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0) {
error = -EINVAL;
goto out_putnames;
}
/*
* To use null names we require CAP_DAC_READ_SEARCH
* This ensures that not everyone will be able to create
* handlink using the passed filedescriptor.
*/
if (flags & AT_EMPTY_PATH && !capable(CAP_DAC_READ_SEARCH)) {
error = -ENOENT;
goto out_putnames;
}
if (flags & AT_SYMLINK_FOLLOW)
how |= LOOKUP_FOLLOW;
retry:
error = filename_lookup(olddfd, old, how, &old_path, NULL);
if (error)
goto out_putnames;
new_dentry = filename_create(newdfd, new, &new_path,
(how & LOOKUP_REVAL));
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto out_putpath;
error = -EXDEV;
if (old_path.mnt != new_path.mnt)
goto out_dput;
idmap = mnt_idmap(new_path.mnt);
error = may_linkat(idmap, &old_path);
if (unlikely(error))
goto out_dput;
error = security_path_link(old_path.dentry, &new_path, new_dentry);
if (error)
goto out_dput;
error = vfs_link(old_path.dentry, idmap, new_path.dentry->d_inode,
new_dentry, &delegated_inode);
out_dput:
done_path_create(&new_path, new_dentry);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error) {
path_put(&old_path);
goto retry;
}
}
if (retry_estale(error, how)) {
path_put(&old_path);
how |= LOOKUP_REVAL;
goto retry;
}
out_putpath:
path_put(&old_path);
out_putnames:
putname(old);
putname(new);
return error;
}
SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname, int, flags)
{
return do_linkat(olddfd, getname_uflags(oldname, flags),
newdfd, getname(newname), flags);
}
SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname)
{
return do_linkat(AT_FDCWD, getname(oldname), AT_FDCWD, getname(newname), 0);
}
/**
* vfs_rename - rename a filesystem object
* @rd: pointer to &struct renamedata info
*
* The caller must hold multiple mutexes--see lock_rename()).
*
* If vfs_rename discovers a delegation in need of breaking at either
* the source or destination, it will return -EWOULDBLOCK and return a
* reference to the inode in delegated_inode. The caller should then
* break the delegation and retry. Because breaking a delegation may
* take a long time, the caller should drop all locks before doing
* so.
*
* Alternatively, a caller may pass NULL for delegated_inode. This may
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported.
*
* The worst of all namespace operations - renaming directory. "Perverted"
* doesn't even start to describe it. Somebody in UCB had a heck of a trip...
* Problems:
*
* a) we can get into loop creation.
* b) race potential - two innocent renames can create a loop together.
* That's where 4.4 screws up. Current fix: serialization on
* sb->s_vfs_rename_mutex. We might be more accurate, but that's another
* story.
* c) we have to lock _four_ objects - parents and victim (if it exists),
* and source.
* And that - after we got ->i_mutex on parents (until then we don't know
* whether the target exists). Solution: try to be smart with locking
* order for inodes. We rely on the fact that tree topology may change
* only under ->s_vfs_rename_mutex _and_ that parent of the object we
* move will be locked. Thus we can rank directories by the tree
* (ancestors first) and rank all non-directories after them.
* That works since everybody except rename does "lock parent, lookup,
* lock child" and rename is under ->s_vfs_rename_mutex.
* HOWEVER, it relies on the assumption that any object with ->lookup()
* has no more than 1 dentry. If "hybrid" objects will ever appear,
* we'd better make sure that there's no link(2) for them.
* d) conversion from fhandle to dentry may come in the wrong moment - when
* we are removing the target. Solution: we will have to grab ->i_mutex
* in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on
* ->i_mutex on parents, which works but leads to some truly excessive
* locking].
*/
int vfs_rename(struct renamedata *rd)
{
int error;
struct inode *old_dir = rd->old_dir, *new_dir = rd->new_dir;
struct dentry *old_dentry = rd->old_dentry;
struct dentry *new_dentry = rd->new_dentry;
struct inode **delegated_inode = rd->delegated_inode;
unsigned int flags = rd->flags;
bool is_dir = d_is_dir(old_dentry);
struct inode *source = old_dentry->d_inode;
struct inode *target = new_dentry->d_inode;
bool new_is_dir = false;
unsigned max_links = new_dir->i_sb->s_max_links;
struct name_snapshot old_name;
if (source == target)
return 0;
error = may_delete(rd->old_mnt_idmap, old_dir, old_dentry, is_dir);
if (error)
return error;
if (!target) {
error = may_create(rd->new_mnt_idmap, new_dir, new_dentry);
} else {
new_is_dir = d_is_dir(new_dentry);
if (!(flags & RENAME_EXCHANGE))
error = may_delete(rd->new_mnt_idmap, new_dir,
new_dentry, is_dir);
else
error = may_delete(rd->new_mnt_idmap, new_dir,
new_dentry, new_is_dir);
}
if (error)
return error;
if (!old_dir->i_op->rename)
return -EPERM;
/*
* If we are going to change the parent - check write permissions,
* we'll need to flip '..'.
*/
if (new_dir != old_dir) {
if (is_dir) {
error = inode_permission(rd->old_mnt_idmap, source,
MAY_WRITE);
if (error)
return error;
}
if ((flags & RENAME_EXCHANGE) && new_is_dir) {
error = inode_permission(rd->new_mnt_idmap, target,
MAY_WRITE);
if (error)
return error;
}
}
error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry,
flags);
if (error)
return error;
take_dentry_name_snapshot(&old_name, old_dentry);
dget(new_dentry);
/*
* Lock all moved children. Moved directories may need to change parent
* pointer so they need the lock to prevent against concurrent
* directory changes moving parent pointer. For regular files we've
* historically always done this. The lockdep locking subclasses are
* somewhat arbitrary but RENAME_EXCHANGE in particular can swap
* regular files and directories so it's difficult to tell which
* subclasses to use.
*/
lock_two_inodes(source, target, I_MUTEX_NORMAL, I_MUTEX_NONDIR2);
error = -EPERM;
if (IS_SWAPFILE(source) || (target && IS_SWAPFILE(target)))
goto out;
error = -EBUSY;
if (is_local_mountpoint(old_dentry) || is_local_mountpoint(new_dentry))
goto out;
if (max_links && new_dir != old_dir) {
error = -EMLINK;
if (is_dir && !new_is_dir && new_dir->i_nlink >= max_links)
goto out;
if ((flags & RENAME_EXCHANGE) && !is_dir && new_is_dir &&
old_dir->i_nlink >= max_links)
goto out;
}
if (!is_dir) {
error = try_break_deleg(source, delegated_inode);
if (error)
goto out;
}
if (target && !new_is_dir) {
error = try_break_deleg(target, delegated_inode);
if (error)
goto out;
}
error = old_dir->i_op->rename(rd->new_mnt_idmap, old_dir, old_dentry,
new_dir, new_dentry, flags);
if (error)
goto out;
if (!(flags & RENAME_EXCHANGE) && target) {
if (is_dir) {
shrink_dcache_parent(new_dentry);
target->i_flags |= S_DEAD;
}
dont_mount(new_dentry);
detach_mounts(new_dentry);
}
if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) {
if (!(flags & RENAME_EXCHANGE))
d_move(old_dentry, new_dentry);
else
d_exchange(old_dentry, new_dentry);
}
out:
inode_unlock(source);
if (target)
inode_unlock(target);
dput(new_dentry);
if (!error) {
fsnotify_move(old_dir, new_dir, &old_name.name, is_dir,
!(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry);
if (flags & RENAME_EXCHANGE) {
fsnotify_move(new_dir, old_dir, &old_dentry->d_name,
new_is_dir, NULL, new_dentry);
}
}
release_dentry_name_snapshot(&old_name);
return error;
}
EXPORT_SYMBOL(vfs_rename);
int do_renameat2(int olddfd, struct filename *from, int newdfd,
struct filename *to, unsigned int flags)
{
struct renamedata rd;
struct dentry *old_dentry, *new_dentry;
struct dentry *trap;
struct path old_path, new_path;
struct qstr old_last, new_last;
int old_type, new_type;
struct inode *delegated_inode = NULL;
unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET;
bool should_retry = false;
int error = -EINVAL;
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
goto put_names;
if ((flags & (RENAME_NOREPLACE | RENAME_WHITEOUT)) &&
(flags & RENAME_EXCHANGE))
goto put_names;
if (flags & RENAME_EXCHANGE)
target_flags = 0;
retry:
error = filename_parentat(olddfd, from, lookup_flags, &old_path,
&old_last, &old_type);
if (error)
goto put_names;
error = filename_parentat(newdfd, to, lookup_flags, &new_path, &new_last,
&new_type);
if (error)
goto exit1;
error = -EXDEV;
if (old_path.mnt != new_path.mnt)
goto exit2;
error = -EBUSY;
if (old_type != LAST_NORM)
goto exit2;
if (flags & RENAME_NOREPLACE)
error = -EEXIST;
if (new_type != LAST_NORM)
goto exit2;
error = mnt_want_write(old_path.mnt);
if (error)
goto exit2;
retry_deleg:
trap = lock_rename(new_path.dentry, old_path.dentry);
old_dentry = lookup_one_qstr_excl(&old_last, old_path.dentry,
lookup_flags);
error = PTR_ERR(old_dentry);
if (IS_ERR(old_dentry))
goto exit3;
/* source must exist */
error = -ENOENT;
if (d_is_negative(old_dentry))
goto exit4;
new_dentry = lookup_one_qstr_excl(&new_last, new_path.dentry,
lookup_flags | target_flags);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto exit4;
error = -EEXIST;
if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry))
goto exit5;
if (flags & RENAME_EXCHANGE) {
error = -ENOENT;
if (d_is_negative(new_dentry))
goto exit5;
if (!d_is_dir(new_dentry)) {
error = -ENOTDIR;
if (new_last.name[new_last.len])
goto exit5;
}
}
/* unless the source is a directory trailing slashes give -ENOTDIR */
if (!d_is_dir(old_dentry)) {
error = -ENOTDIR;
if (old_last.name[old_last.len])
goto exit5;
if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len])
goto exit5;
}
/* source should not be ancestor of target */
error = -EINVAL;
if (old_dentry == trap)
goto exit5;
/* target should not be an ancestor of source */
if (!(flags & RENAME_EXCHANGE))
error = -ENOTEMPTY;
if (new_dentry == trap)
goto exit5;
error = security_path_rename(&old_path, old_dentry,
&new_path, new_dentry, flags);
if (error)
goto exit5;
rd.old_dir = old_path.dentry->d_inode;
rd.old_dentry = old_dentry;
rd.old_mnt_idmap = mnt_idmap(old_path.mnt);
rd.new_dir = new_path.dentry->d_inode;
rd.new_dentry = new_dentry;
rd.new_mnt_idmap = mnt_idmap(new_path.mnt);
rd.delegated_inode = &delegated_inode;
rd.flags = flags;
error = vfs_rename(&rd);
exit5:
dput(new_dentry);
exit4:
dput(old_dentry);
exit3:
unlock_rename(new_path.dentry, old_path.dentry);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
mnt_drop_write(old_path.mnt);
exit2:
if (retry_estale(error, lookup_flags))
should_retry = true;
path_put(&new_path);
exit1:
path_put(&old_path);
if (should_retry) {
should_retry = false;
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
put_names:
putname(from);
putname(to);
return error;
}
SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname, unsigned int, flags)
{
return do_renameat2(olddfd, getname(oldname), newdfd, getname(newname),
flags);
}
SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
return do_renameat2(olddfd, getname(oldname), newdfd, getname(newname),
0);
}
SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
{
return do_renameat2(AT_FDCWD, getname(oldname), AT_FDCWD,
getname(newname), 0);
}
int readlink_copy(char __user *buffer, int buflen, const char *link)
{
int len = PTR_ERR(link);
if (IS_ERR(link))
goto out;
len = strlen(link);
if (len > (unsigned) buflen)
len = buflen;
if (copy_to_user(buffer, link, len))
len = -EFAULT;
out:
return len;
}
/**
* vfs_readlink - copy symlink body into userspace buffer
* @dentry: dentry on which to get symbolic link
* @buffer: user memory pointer
* @buflen: size of buffer
*
* Does not touch atime. That's up to the caller if necessary
*
* Does not call security hook.
*/
int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
struct inode *inode = d_inode(dentry);
DEFINE_DELAYED_CALL(done);
const char *link;
int res;
if (unlikely(!(inode->i_opflags & IOP_DEFAULT_READLINK))) {
if (unlikely(inode->i_op->readlink))
return inode->i_op->readlink(dentry, buffer, buflen);
if (!d_is_symlink(dentry))
return -EINVAL;
spin_lock(&inode->i_lock);
inode->i_opflags |= IOP_DEFAULT_READLINK;
spin_unlock(&inode->i_lock);
}
link = READ_ONCE(inode->i_link);
if (!link) {
link = inode->i_op->get_link(dentry, inode, &done);
if (IS_ERR(link))
return PTR_ERR(link);
}
res = readlink_copy(buffer, buflen, link);
do_delayed_call(&done);
return res;
}
EXPORT_SYMBOL(vfs_readlink);
/**
* vfs_get_link - get symlink body
* @dentry: dentry on which to get symbolic link
* @done: caller needs to free returned data with this
*
* Calls security hook and i_op->get_link() on the supplied inode.
*
* It does not touch atime. That's up to the caller if necessary.
*
* Does not work on "special" symlinks like /proc/$$/fd/N
*/
const char *vfs_get_link(struct dentry *dentry, struct delayed_call *done)
{
const char *res = ERR_PTR(-EINVAL);
struct inode *inode = d_inode(dentry);
if (d_is_symlink(dentry)) {
res = ERR_PTR(security_inode_readlink(dentry));
if (!res)
res = inode->i_op->get_link(dentry, inode, done);
}
return res;
}
EXPORT_SYMBOL(vfs_get_link);
/* get the link contents into pagecache */
const char *page_get_link(struct dentry *dentry, struct inode *inode,
struct delayed_call *callback)
{
char *kaddr;
struct page *page;
struct address_space *mapping = inode->i_mapping;
if (!dentry) {
page = find_get_page(mapping, 0);
if (!page)
return ERR_PTR(-ECHILD);
if (!PageUptodate(page)) {
put_page(page);
return ERR_PTR(-ECHILD);
}
} else {
page = read_mapping_page(mapping, 0, NULL);
if (IS_ERR(page))
return (char*)page;
}
set_delayed_call(callback, page_put_link, page);
BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
kaddr = page_address(page);
nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
return kaddr;
}
EXPORT_SYMBOL(page_get_link);
void page_put_link(void *arg)
{
put_page(arg);
}
EXPORT_SYMBOL(page_put_link);
int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
DEFINE_DELAYED_CALL(done);
int res = readlink_copy(buffer, buflen,
page_get_link(dentry, d_inode(dentry),
&done));
do_delayed_call(&done);
return res;
}
EXPORT_SYMBOL(page_readlink);
int page_symlink(struct inode *inode, const char *symname, int len)
{
struct address_space *mapping = inode->i_mapping;
const struct address_space_operations *aops = mapping->a_ops;
bool nofs = !mapping_gfp_constraint(mapping, __GFP_FS);
struct page *page;
void *fsdata = NULL;
int err;
unsigned int flags;
retry:
if (nofs)
flags = memalloc_nofs_save();
err = aops->write_begin(NULL, mapping, 0, len-1, &page, &fsdata);
if (nofs)
memalloc_nofs_restore(flags);
if (err)
goto fail;
memcpy(page_address(page), symname, len-1);
err = aops->write_end(NULL, mapping, 0, len-1, len-1,
page, fsdata);
if (err < 0)
goto fail;
if (err < len-1)
goto retry;
mark_inode_dirty(inode);
return 0;
fail:
return err;
}
EXPORT_SYMBOL(page_symlink);
const struct inode_operations page_symlink_inode_operations = {
.get_link = page_get_link,
};
EXPORT_SYMBOL(page_symlink_inode_operations);
| linux-master | fs/namei.c |
// SPDX-License-Identifier: GPL-2.0
/*
* High-level sync()-related operations
*/
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/syscalls.h>
#include <linux/linkage.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/backing-dev.h>
#include "internal.h"
#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
SYNC_FILE_RANGE_WAIT_AFTER)
/*
* Write out and wait upon all dirty data associated with this
* superblock. Filesystem data as well as the underlying block
* device. Takes the superblock lock.
*/
int sync_filesystem(struct super_block *sb)
{
int ret = 0;
/*
* We need to be protected against the filesystem going from
* r/o to r/w or vice versa.
*/
WARN_ON(!rwsem_is_locked(&sb->s_umount));
/*
* No point in syncing out anything if the filesystem is read-only.
*/
if (sb_rdonly(sb))
return 0;
/*
* Do the filesystem syncing work. For simple filesystems
* writeback_inodes_sb(sb) just dirties buffers with inodes so we have
* to submit I/O for these buffers via sync_blockdev(). This also
* speeds up the wait == 1 case since in that case write_inode()
* methods call sync_dirty_buffer() and thus effectively write one block
* at a time.
*/
writeback_inodes_sb(sb, WB_REASON_SYNC);
if (sb->s_op->sync_fs) {
ret = sb->s_op->sync_fs(sb, 0);
if (ret)
return ret;
}
ret = sync_blockdev_nowait(sb->s_bdev);
if (ret)
return ret;
sync_inodes_sb(sb);
if (sb->s_op->sync_fs) {
ret = sb->s_op->sync_fs(sb, 1);
if (ret)
return ret;
}
return sync_blockdev(sb->s_bdev);
}
EXPORT_SYMBOL(sync_filesystem);
static void sync_inodes_one_sb(struct super_block *sb, void *arg)
{
if (!sb_rdonly(sb))
sync_inodes_sb(sb);
}
static void sync_fs_one_sb(struct super_block *sb, void *arg)
{
if (!sb_rdonly(sb) && !(sb->s_iflags & SB_I_SKIP_SYNC) &&
sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, *(int *)arg);
}
/*
* Sync everything. We start by waking flusher threads so that most of
* writeback runs on all devices in parallel. Then we sync all inodes reliably
* which effectively also waits for all flusher threads to finish doing
* writeback. At this point all data is on disk so metadata should be stable
* and we tell filesystems to sync their metadata via ->sync_fs() calls.
* Finally, we writeout all block devices because some filesystems (e.g. ext2)
* just write metadata (such as inodes or bitmaps) to block device page cache
* and do not sync it on their own in ->sync_fs().
*/
void ksys_sync(void)
{
int nowait = 0, wait = 1;
wakeup_flusher_threads(WB_REASON_SYNC);
iterate_supers(sync_inodes_one_sb, NULL);
iterate_supers(sync_fs_one_sb, &nowait);
iterate_supers(sync_fs_one_sb, &wait);
sync_bdevs(false);
sync_bdevs(true);
if (unlikely(laptop_mode))
laptop_sync_completion();
}
SYSCALL_DEFINE0(sync)
{
ksys_sync();
return 0;
}
static void do_sync_work(struct work_struct *work)
{
int nowait = 0;
/*
* Sync twice to reduce the possibility we skipped some inodes / pages
* because they were temporarily locked
*/
iterate_supers(sync_inodes_one_sb, &nowait);
iterate_supers(sync_fs_one_sb, &nowait);
sync_bdevs(false);
iterate_supers(sync_inodes_one_sb, &nowait);
iterate_supers(sync_fs_one_sb, &nowait);
sync_bdevs(false);
printk("Emergency Sync complete\n");
kfree(work);
}
void emergency_sync(void)
{
struct work_struct *work;
work = kmalloc(sizeof(*work), GFP_ATOMIC);
if (work) {
INIT_WORK(work, do_sync_work);
schedule_work(work);
}
}
/*
* sync a single super
*/
SYSCALL_DEFINE1(syncfs, int, fd)
{
struct fd f = fdget(fd);
struct super_block *sb;
int ret, ret2;
if (!f.file)
return -EBADF;
sb = f.file->f_path.dentry->d_sb;
down_read(&sb->s_umount);
ret = sync_filesystem(sb);
up_read(&sb->s_umount);
ret2 = errseq_check_and_advance(&sb->s_wb_err, &f.file->f_sb_err);
fdput(f);
return ret ? ret : ret2;
}
/**
* vfs_fsync_range - helper to sync a range of data & metadata to disk
* @file: file to sync
* @start: offset in bytes of the beginning of data range to sync
* @end: offset in bytes of the end of data range (inclusive)
* @datasync: perform only datasync
*
* Write back data in range @start..@end and metadata for @file to disk. If
* @datasync is set only metadata needed to access modified file data is
* written.
*/
int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync)
{
struct inode *inode = file->f_mapping->host;
if (!file->f_op->fsync)
return -EINVAL;
if (!datasync && (inode->i_state & I_DIRTY_TIME))
mark_inode_dirty_sync(inode);
return file->f_op->fsync(file, start, end, datasync);
}
EXPORT_SYMBOL(vfs_fsync_range);
/**
* vfs_fsync - perform a fsync or fdatasync on a file
* @file: file to sync
* @datasync: only perform a fdatasync operation
*
* Write back data and metadata for @file to disk. If @datasync is
* set only metadata needed to access modified file data is written.
*/
int vfs_fsync(struct file *file, int datasync)
{
return vfs_fsync_range(file, 0, LLONG_MAX, datasync);
}
EXPORT_SYMBOL(vfs_fsync);
static int do_fsync(unsigned int fd, int datasync)
{
struct fd f = fdget(fd);
int ret = -EBADF;
if (f.file) {
ret = vfs_fsync(f.file, datasync);
fdput(f);
}
return ret;
}
SYSCALL_DEFINE1(fsync, unsigned int, fd)
{
return do_fsync(fd, 0);
}
SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
{
return do_fsync(fd, 1);
}
int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,
unsigned int flags)
{
int ret;
struct address_space *mapping;
loff_t endbyte; /* inclusive */
umode_t i_mode;
ret = -EINVAL;
if (flags & ~VALID_FLAGS)
goto out;
endbyte = offset + nbytes;
if ((s64)offset < 0)
goto out;
if ((s64)endbyte < 0)
goto out;
if (endbyte < offset)
goto out;
if (sizeof(pgoff_t) == 4) {
if (offset >= (0x100000000ULL << PAGE_SHIFT)) {
/*
* The range starts outside a 32 bit machine's
* pagecache addressing capabilities. Let it "succeed"
*/
ret = 0;
goto out;
}
if (endbyte >= (0x100000000ULL << PAGE_SHIFT)) {
/*
* Out to EOF
*/
nbytes = 0;
}
}
if (nbytes == 0)
endbyte = LLONG_MAX;
else
endbyte--; /* inclusive */
i_mode = file_inode(file)->i_mode;
ret = -ESPIPE;
if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
!S_ISLNK(i_mode))
goto out;
mapping = file->f_mapping;
ret = 0;
if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
ret = file_fdatawait_range(file, offset, endbyte);
if (ret < 0)
goto out;
}
if (flags & SYNC_FILE_RANGE_WRITE) {
int sync_mode = WB_SYNC_NONE;
if ((flags & SYNC_FILE_RANGE_WRITE_AND_WAIT) ==
SYNC_FILE_RANGE_WRITE_AND_WAIT)
sync_mode = WB_SYNC_ALL;
ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
sync_mode);
if (ret < 0)
goto out;
}
if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
ret = file_fdatawait_range(file, offset, endbyte);
out:
return ret;
}
/*
* ksys_sync_file_range() permits finely controlled syncing over a segment of
* a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
* zero then ksys_sync_file_range() will operate from offset out to EOF.
*
* The flag bits are:
*
* SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
* before performing the write.
*
* SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
* range which are not presently under writeback. Note that this may block for
* significant periods due to exhaustion of disk request structures.
*
* SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
* after performing the write.
*
* Useful combinations of the flag bits are:
*
* SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
* in the range which were dirty on entry to ksys_sync_file_range() are placed
* under writeout. This is a start-write-for-data-integrity operation.
*
* SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
* are not presently under writeout. This is an asynchronous flush-to-disk
* operation. Not suitable for data integrity operations.
*
* SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
* completion of writeout of all pages in the range. This will be used after an
* earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
* for that operation to complete and to return the result.
*
* SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER
* (a.k.a. SYNC_FILE_RANGE_WRITE_AND_WAIT):
* a traditional sync() operation. This is a write-for-data-integrity operation
* which will ensure that all pages in the range which were dirty on entry to
* ksys_sync_file_range() are written to disk. It should be noted that disk
* caches are not flushed by this call, so there are no guarantees here that the
* data will be available on disk after a crash.
*
*
* SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
* I/O errors or ENOSPC conditions and will return those to the caller, after
* clearing the EIO and ENOSPC flags in the address_space.
*
* It should be noted that none of these operations write out the file's
* metadata. So unless the application is strictly performing overwrites of
* already-instantiated disk blocks, there are no guarantees here that the data
* will be available after a crash.
*/
int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
unsigned int flags)
{
int ret;
struct fd f;
ret = -EBADF;
f = fdget(fd);
if (f.file)
ret = sync_file_range(f.file, offset, nbytes, flags);
fdput(f);
return ret;
}
SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
unsigned int, flags)
{
return ksys_sync_file_range(fd, offset, nbytes, flags);
}
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_SYNC_FILE_RANGE)
COMPAT_SYSCALL_DEFINE6(sync_file_range, int, fd, compat_arg_u64_dual(offset),
compat_arg_u64_dual(nbytes), unsigned int, flags)
{
return ksys_sync_file_range(fd, compat_arg_u64_glue(offset),
compat_arg_u64_glue(nbytes), flags);
}
#endif
/* It would be nice if people remember that not all the world's an i386
when they introduce new system calls */
SYSCALL_DEFINE4(sync_file_range2, int, fd, unsigned int, flags,
loff_t, offset, loff_t, nbytes)
{
return ksys_sync_file_range(fd, offset, nbytes, flags);
}
| linux-master | fs/sync.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/binfmt_elf.c
*
* These are the functions used to load ELF format executables as used
* on SVr4 machines. Information on the format may be found in the book
* "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
* Tools".
*
* Copyright 1993, 1994: Eric Youngdale ([email protected]).
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/log2.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/compiler.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/security.h>
#include <linux/random.h>
#include <linux/elf.h>
#include <linux/elf-randomize.h>
#include <linux/utsname.h>
#include <linux/coredump.h>
#include <linux/sched.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/cputime.h>
#include <linux/sizes.h>
#include <linux/types.h>
#include <linux/cred.h>
#include <linux/dax.h>
#include <linux/uaccess.h>
#include <linux/rseq.h>
#include <asm/param.h>
#include <asm/page.h>
#ifndef ELF_COMPAT
#define ELF_COMPAT 0
#endif
#ifndef user_long_t
#define user_long_t long
#endif
#ifndef user_siginfo_t
#define user_siginfo_t siginfo_t
#endif
/* That's for binfmt_elf_fdpic to deal with */
#ifndef elf_check_fdpic
#define elf_check_fdpic(ex) false
#endif
static int load_elf_binary(struct linux_binprm *bprm);
#ifdef CONFIG_USELIB
static int load_elf_library(struct file *);
#else
#define load_elf_library NULL
#endif
/*
* If we don't support core dumping, then supply a NULL so we
* don't even try.
*/
#ifdef CONFIG_ELF_CORE
static int elf_core_dump(struct coredump_params *cprm);
#else
#define elf_core_dump NULL
#endif
#if ELF_EXEC_PAGESIZE > PAGE_SIZE
#define ELF_MIN_ALIGN ELF_EXEC_PAGESIZE
#else
#define ELF_MIN_ALIGN PAGE_SIZE
#endif
#ifndef ELF_CORE_EFLAGS
#define ELF_CORE_EFLAGS 0
#endif
#define ELF_PAGESTART(_v) ((_v) & ~(int)(ELF_MIN_ALIGN-1))
#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
static struct linux_binfmt elf_format = {
.module = THIS_MODULE,
.load_binary = load_elf_binary,
.load_shlib = load_elf_library,
#ifdef CONFIG_COREDUMP
.core_dump = elf_core_dump,
.min_coredump = ELF_EXEC_PAGESIZE,
#endif
};
#define BAD_ADDR(x) (unlikely((unsigned long)(x) >= TASK_SIZE))
static int set_brk(unsigned long start, unsigned long end, int prot)
{
start = ELF_PAGEALIGN(start);
end = ELF_PAGEALIGN(end);
if (end > start) {
/*
* Map the last of the bss segment.
* If the header is requesting these pages to be
* executable, honour that (ppc32 needs this).
*/
int error = vm_brk_flags(start, end - start,
prot & PROT_EXEC ? VM_EXEC : 0);
if (error)
return error;
}
current->mm->start_brk = current->mm->brk = end;
return 0;
}
/* We need to explicitly zero any fractional pages
after the data section (i.e. bss). This would
contain the junk from the file that should not
be in memory
*/
static int padzero(unsigned long elf_bss)
{
unsigned long nbyte;
nbyte = ELF_PAGEOFFSET(elf_bss);
if (nbyte) {
nbyte = ELF_MIN_ALIGN - nbyte;
if (clear_user((void __user *) elf_bss, nbyte))
return -EFAULT;
}
return 0;
}
/* Let's use some macros to make this stack manipulation a little clearer */
#ifdef CONFIG_STACK_GROWSUP
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
#define STACK_ROUND(sp, items) \
((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
#define STACK_ALLOC(sp, len) ({ \
elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
old_sp; })
#else
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
#define STACK_ROUND(sp, items) \
(((unsigned long) (sp - items)) &~ 15UL)
#define STACK_ALLOC(sp, len) (sp -= len)
#endif
#ifndef ELF_BASE_PLATFORM
/*
* AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
* If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
* will be copied to the user stack in the same manner as AT_PLATFORM.
*/
#define ELF_BASE_PLATFORM NULL
#endif
static int
create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec,
unsigned long interp_load_addr,
unsigned long e_entry, unsigned long phdr_addr)
{
struct mm_struct *mm = current->mm;
unsigned long p = bprm->p;
int argc = bprm->argc;
int envc = bprm->envc;
elf_addr_t __user *sp;
elf_addr_t __user *u_platform;
elf_addr_t __user *u_base_platform;
elf_addr_t __user *u_rand_bytes;
const char *k_platform = ELF_PLATFORM;
const char *k_base_platform = ELF_BASE_PLATFORM;
unsigned char k_rand_bytes[16];
int items;
elf_addr_t *elf_info;
elf_addr_t flags = 0;
int ei_index;
const struct cred *cred = current_cred();
struct vm_area_struct *vma;
/*
* In some cases (e.g. Hyper-Threading), we want to avoid L1
* evictions by the processes running on the same package. One
* thing we can do is to shuffle the initial stack for them.
*/
p = arch_align_stack(p);
/*
* If this architecture has a platform capability string, copy it
* to userspace. In some cases (Sparc), this info is impossible
* for userspace to get any other way, in others (i386) it is
* merely difficult.
*/
u_platform = NULL;
if (k_platform) {
size_t len = strlen(k_platform) + 1;
u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
if (copy_to_user(u_platform, k_platform, len))
return -EFAULT;
}
/*
* If this architecture has a "base" platform capability
* string, copy it to userspace.
*/
u_base_platform = NULL;
if (k_base_platform) {
size_t len = strlen(k_base_platform) + 1;
u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
if (copy_to_user(u_base_platform, k_base_platform, len))
return -EFAULT;
}
/*
* Generate 16 random bytes for userspace PRNG seeding.
*/
get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
u_rand_bytes = (elf_addr_t __user *)
STACK_ALLOC(p, sizeof(k_rand_bytes));
if (copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
return -EFAULT;
/* Create the ELF interpreter info */
elf_info = (elf_addr_t *)mm->saved_auxv;
/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
#define NEW_AUX_ENT(id, val) \
do { \
*elf_info++ = id; \
*elf_info++ = val; \
} while (0)
#ifdef ARCH_DLINFO
/*
* ARCH_DLINFO must come first so PPC can do its special alignment of
* AUXV.
* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
* ARCH_DLINFO changes
*/
ARCH_DLINFO;
#endif
NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
NEW_AUX_ENT(AT_PHDR, phdr_addr);
NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
NEW_AUX_ENT(AT_BASE, interp_load_addr);
if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0)
flags |= AT_FLAGS_PRESERVE_ARGV0;
NEW_AUX_ENT(AT_FLAGS, flags);
NEW_AUX_ENT(AT_ENTRY, e_entry);
NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
#ifdef ELF_HWCAP2
NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
#endif
NEW_AUX_ENT(AT_EXECFN, bprm->exec);
if (k_platform) {
NEW_AUX_ENT(AT_PLATFORM,
(elf_addr_t)(unsigned long)u_platform);
}
if (k_base_platform) {
NEW_AUX_ENT(AT_BASE_PLATFORM,
(elf_addr_t)(unsigned long)u_base_platform);
}
if (bprm->have_execfd) {
NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
}
#ifdef CONFIG_RSEQ
NEW_AUX_ENT(AT_RSEQ_FEATURE_SIZE, offsetof(struct rseq, end));
NEW_AUX_ENT(AT_RSEQ_ALIGN, __alignof__(struct rseq));
#endif
#undef NEW_AUX_ENT
/* AT_NULL is zero; clear the rest too */
memset(elf_info, 0, (char *)mm->saved_auxv +
sizeof(mm->saved_auxv) - (char *)elf_info);
/* And advance past the AT_NULL entry. */
elf_info += 2;
ei_index = elf_info - (elf_addr_t *)mm->saved_auxv;
sp = STACK_ADD(p, ei_index);
items = (argc + 1) + (envc + 1) + 1;
bprm->p = STACK_ROUND(sp, items);
/* Point sp at the lowest address on the stack */
#ifdef CONFIG_STACK_GROWSUP
sp = (elf_addr_t __user *)bprm->p - items - ei_index;
bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
#else
sp = (elf_addr_t __user *)bprm->p;
#endif
/*
* Grow the stack manually; some architectures have a limit on how
* far ahead a user-space access may be in order to grow the stack.
*/
if (mmap_write_lock_killable(mm))
return -EINTR;
vma = find_extend_vma_locked(mm, bprm->p);
mmap_write_unlock(mm);
if (!vma)
return -EFAULT;
/* Now, let's put argc (and argv, envp if appropriate) on the stack */
if (put_user(argc, sp++))
return -EFAULT;
/* Populate list of argv pointers back to argv strings. */
p = mm->arg_end = mm->arg_start;
while (argc-- > 0) {
size_t len;
if (put_user((elf_addr_t)p, sp++))
return -EFAULT;
len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(0, sp++))
return -EFAULT;
mm->arg_end = p;
/* Populate list of envp pointers back to envp strings. */
mm->env_end = mm->env_start = p;
while (envc-- > 0) {
size_t len;
if (put_user((elf_addr_t)p, sp++))
return -EFAULT;
len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
if (put_user(0, sp++))
return -EFAULT;
mm->env_end = p;
/* Put the elf_info on the stack in the right place. */
if (copy_to_user(sp, mm->saved_auxv, ei_index * sizeof(elf_addr_t)))
return -EFAULT;
return 0;
}
static unsigned long elf_map(struct file *filep, unsigned long addr,
const struct elf_phdr *eppnt, int prot, int type,
unsigned long total_size)
{
unsigned long map_addr;
unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
addr = ELF_PAGESTART(addr);
size = ELF_PAGEALIGN(size);
/* mmap() will return -EINVAL if given a zero size, but a
* segment with zero filesize is perfectly valid */
if (!size)
return addr;
/*
* total_size is the size of the ELF (interpreter) image.
* The _first_ mmap needs to know the full size, otherwise
* randomization might put this image into an overlapping
* position with the ELF binary image. (since size < total_size)
* So we first map the 'big' image - and unmap the remainder at
* the end. (which unmap is needed for ELF images with holes.)
*/
if (total_size) {
total_size = ELF_PAGEALIGN(total_size);
map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
if (!BAD_ADDR(map_addr))
vm_munmap(map_addr+size, total_size-size);
} else
map_addr = vm_mmap(filep, addr, size, prot, type, off);
if ((type & MAP_FIXED_NOREPLACE) &&
PTR_ERR((void *)map_addr) == -EEXIST)
pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
task_pid_nr(current), current->comm, (void *)addr);
return(map_addr);
}
static unsigned long total_mapping_size(const struct elf_phdr *phdr, int nr)
{
elf_addr_t min_addr = -1;
elf_addr_t max_addr = 0;
bool pt_load = false;
int i;
for (i = 0; i < nr; i++) {
if (phdr[i].p_type == PT_LOAD) {
min_addr = min(min_addr, ELF_PAGESTART(phdr[i].p_vaddr));
max_addr = max(max_addr, phdr[i].p_vaddr + phdr[i].p_memsz);
pt_load = true;
}
}
return pt_load ? (max_addr - min_addr) : 0;
}
static int elf_read(struct file *file, void *buf, size_t len, loff_t pos)
{
ssize_t rv;
rv = kernel_read(file, buf, len, &pos);
if (unlikely(rv != len)) {
return (rv < 0) ? rv : -EIO;
}
return 0;
}
static unsigned long maximum_alignment(struct elf_phdr *cmds, int nr)
{
unsigned long alignment = 0;
int i;
for (i = 0; i < nr; i++) {
if (cmds[i].p_type == PT_LOAD) {
unsigned long p_align = cmds[i].p_align;
/* skip non-power of two alignments as invalid */
if (!is_power_of_2(p_align))
continue;
alignment = max(alignment, p_align);
}
}
/* ensure we align to at least one page */
return ELF_PAGEALIGN(alignment);
}
/**
* load_elf_phdrs() - load ELF program headers
* @elf_ex: ELF header of the binary whose program headers should be loaded
* @elf_file: the opened ELF binary file
*
* Loads ELF program headers from the binary file elf_file, which has the ELF
* header pointed to by elf_ex, into a newly allocated array. The caller is
* responsible for freeing the allocated data. Returns NULL upon failure.
*/
static struct elf_phdr *load_elf_phdrs(const struct elfhdr *elf_ex,
struct file *elf_file)
{
struct elf_phdr *elf_phdata = NULL;
int retval = -1;
unsigned int size;
/*
* If the size of this structure has changed, then punt, since
* we will be doing the wrong thing.
*/
if (elf_ex->e_phentsize != sizeof(struct elf_phdr))
goto out;
/* Sanity check the number of program headers... */
/* ...and their total size. */
size = sizeof(struct elf_phdr) * elf_ex->e_phnum;
if (size == 0 || size > 65536 || size > ELF_MIN_ALIGN)
goto out;
elf_phdata = kmalloc(size, GFP_KERNEL);
if (!elf_phdata)
goto out;
/* Read in the program headers */
retval = elf_read(elf_file, elf_phdata, size, elf_ex->e_phoff);
out:
if (retval) {
kfree(elf_phdata);
elf_phdata = NULL;
}
return elf_phdata;
}
#ifndef CONFIG_ARCH_BINFMT_ELF_STATE
/**
* struct arch_elf_state - arch-specific ELF loading state
*
* This structure is used to preserve architecture specific data during
* the loading of an ELF file, throughout the checking of architecture
* specific ELF headers & through to the point where the ELF load is
* known to be proceeding (ie. SET_PERSONALITY).
*
* This implementation is a dummy for architectures which require no
* specific state.
*/
struct arch_elf_state {
};
#define INIT_ARCH_ELF_STATE {}
/**
* arch_elf_pt_proc() - check a PT_LOPROC..PT_HIPROC ELF program header
* @ehdr: The main ELF header
* @phdr: The program header to check
* @elf: The open ELF file
* @is_interp: True if the phdr is from the interpreter of the ELF being
* loaded, else false.
* @state: Architecture-specific state preserved throughout the process
* of loading the ELF.
*
* Inspects the program header phdr to validate its correctness and/or
* suitability for the system. Called once per ELF program header in the
* range PT_LOPROC to PT_HIPROC, for both the ELF being loaded and its
* interpreter.
*
* Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
* with that return code.
*/
static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
struct elf_phdr *phdr,
struct file *elf, bool is_interp,
struct arch_elf_state *state)
{
/* Dummy implementation, always proceed */
return 0;
}
/**
* arch_check_elf() - check an ELF executable
* @ehdr: The main ELF header
* @has_interp: True if the ELF has an interpreter, else false.
* @interp_ehdr: The interpreter's ELF header
* @state: Architecture-specific state preserved throughout the process
* of loading the ELF.
*
* Provides a final opportunity for architecture code to reject the loading
* of the ELF & cause an exec syscall to return an error. This is called after
* all program headers to be checked by arch_elf_pt_proc have been.
*
* Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
* with that return code.
*/
static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
struct elfhdr *interp_ehdr,
struct arch_elf_state *state)
{
/* Dummy implementation, always proceed */
return 0;
}
#endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state,
bool has_interp, bool is_interp)
{
int prot = 0;
if (p_flags & PF_R)
prot |= PROT_READ;
if (p_flags & PF_W)
prot |= PROT_WRITE;
if (p_flags & PF_X)
prot |= PROT_EXEC;
return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp);
}
/* This is much more generalized than the library routine read function,
so we keep this separate. Technically the library read function
is only provided so that we can read a.out libraries that have
an ELF header */
static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
struct file *interpreter,
unsigned long no_base, struct elf_phdr *interp_elf_phdata,
struct arch_elf_state *arch_state)
{
struct elf_phdr *eppnt;
unsigned long load_addr = 0;
int load_addr_set = 0;
unsigned long last_bss = 0, elf_bss = 0;
int bss_prot = 0;
unsigned long error = ~0UL;
unsigned long total_size;
int i;
/* First of all, some simple consistency checks */
if (interp_elf_ex->e_type != ET_EXEC &&
interp_elf_ex->e_type != ET_DYN)
goto out;
if (!elf_check_arch(interp_elf_ex) ||
elf_check_fdpic(interp_elf_ex))
goto out;
if (!interpreter->f_op->mmap)
goto out;
total_size = total_mapping_size(interp_elf_phdata,
interp_elf_ex->e_phnum);
if (!total_size) {
error = -EINVAL;
goto out;
}
eppnt = interp_elf_phdata;
for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
if (eppnt->p_type == PT_LOAD) {
int elf_type = MAP_PRIVATE;
int elf_prot = make_prot(eppnt->p_flags, arch_state,
true, true);
unsigned long vaddr = 0;
unsigned long k, map_addr;
vaddr = eppnt->p_vaddr;
if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
elf_type |= MAP_FIXED;
else if (no_base && interp_elf_ex->e_type == ET_DYN)
load_addr = -vaddr;
map_addr = elf_map(interpreter, load_addr + vaddr,
eppnt, elf_prot, elf_type, total_size);
total_size = 0;
error = map_addr;
if (BAD_ADDR(map_addr))
goto out;
if (!load_addr_set &&
interp_elf_ex->e_type == ET_DYN) {
load_addr = map_addr - ELF_PAGESTART(vaddr);
load_addr_set = 1;
}
/*
* Check to see if the section's size will overflow the
* allowed task size. Note that p_filesz must always be
* <= p_memsize so it's only necessary to check p_memsz.
*/
k = load_addr + eppnt->p_vaddr;
if (BAD_ADDR(k) ||
eppnt->p_filesz > eppnt->p_memsz ||
eppnt->p_memsz > TASK_SIZE ||
TASK_SIZE - eppnt->p_memsz < k) {
error = -ENOMEM;
goto out;
}
/*
* Find the end of the file mapping for this phdr, and
* keep track of the largest address we see for this.
*/
k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
if (k > elf_bss)
elf_bss = k;
/*
* Do the same thing for the memory mapping - between
* elf_bss and last_bss is the bss section.
*/
k = load_addr + eppnt->p_vaddr + eppnt->p_memsz;
if (k > last_bss) {
last_bss = k;
bss_prot = elf_prot;
}
}
}
/*
* Now fill out the bss section: first pad the last page from
* the file up to the page boundary, and zero it from elf_bss
* up to the end of the page.
*/
if (padzero(elf_bss)) {
error = -EFAULT;
goto out;
}
/*
* Next, align both the file and mem bss up to the page size,
* since this is where elf_bss was just zeroed up to, and where
* last_bss will end after the vm_brk_flags() below.
*/
elf_bss = ELF_PAGEALIGN(elf_bss);
last_bss = ELF_PAGEALIGN(last_bss);
/* Finally, if there is still more bss to allocate, do it. */
if (last_bss > elf_bss) {
error = vm_brk_flags(elf_bss, last_bss - elf_bss,
bss_prot & PROT_EXEC ? VM_EXEC : 0);
if (error)
goto out;
}
error = load_addr;
out:
return error;
}
/*
* These are the functions used to load ELF style executables and shared
* libraries. There is no binary dependent code anywhere else.
*/
static int parse_elf_property(const char *data, size_t *off, size_t datasz,
struct arch_elf_state *arch,
bool have_prev_type, u32 *prev_type)
{
size_t o, step;
const struct gnu_property *pr;
int ret;
if (*off == datasz)
return -ENOENT;
if (WARN_ON_ONCE(*off > datasz || *off % ELF_GNU_PROPERTY_ALIGN))
return -EIO;
o = *off;
datasz -= *off;
if (datasz < sizeof(*pr))
return -ENOEXEC;
pr = (const struct gnu_property *)(data + o);
o += sizeof(*pr);
datasz -= sizeof(*pr);
if (pr->pr_datasz > datasz)
return -ENOEXEC;
WARN_ON_ONCE(o % ELF_GNU_PROPERTY_ALIGN);
step = round_up(pr->pr_datasz, ELF_GNU_PROPERTY_ALIGN);
if (step > datasz)
return -ENOEXEC;
/* Properties are supposed to be unique and sorted on pr_type: */
if (have_prev_type && pr->pr_type <= *prev_type)
return -ENOEXEC;
*prev_type = pr->pr_type;
ret = arch_parse_elf_property(pr->pr_type, data + o,
pr->pr_datasz, ELF_COMPAT, arch);
if (ret)
return ret;
*off = o + step;
return 0;
}
#define NOTE_DATA_SZ SZ_1K
#define GNU_PROPERTY_TYPE_0_NAME "GNU"
#define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME))
static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
struct arch_elf_state *arch)
{
union {
struct elf_note nhdr;
char data[NOTE_DATA_SZ];
} note;
loff_t pos;
ssize_t n;
size_t off, datasz;
int ret;
bool have_prev_type;
u32 prev_type;
if (!IS_ENABLED(CONFIG_ARCH_USE_GNU_PROPERTY) || !phdr)
return 0;
/* load_elf_binary() shouldn't call us unless this is true... */
if (WARN_ON_ONCE(phdr->p_type != PT_GNU_PROPERTY))
return -ENOEXEC;
/* If the properties are crazy large, that's too bad (for now): */
if (phdr->p_filesz > sizeof(note))
return -ENOEXEC;
pos = phdr->p_offset;
n = kernel_read(f, ¬e, phdr->p_filesz, &pos);
BUILD_BUG_ON(sizeof(note) < sizeof(note.nhdr) + NOTE_NAME_SZ);
if (n < 0 || n < sizeof(note.nhdr) + NOTE_NAME_SZ)
return -EIO;
if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 ||
note.nhdr.n_namesz != NOTE_NAME_SZ ||
strncmp(note.data + sizeof(note.nhdr),
GNU_PROPERTY_TYPE_0_NAME, n - sizeof(note.nhdr)))
return -ENOEXEC;
off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ,
ELF_GNU_PROPERTY_ALIGN);
if (off > n)
return -ENOEXEC;
if (note.nhdr.n_descsz > n - off)
return -ENOEXEC;
datasz = off + note.nhdr.n_descsz;
have_prev_type = false;
do {
ret = parse_elf_property(note.data, &off, datasz, arch,
have_prev_type, &prev_type);
have_prev_type = true;
} while (!ret);
return ret == -ENOENT ? 0 : ret;
}
static int load_elf_binary(struct linux_binprm *bprm)
{
struct file *interpreter = NULL; /* to shut gcc up */
unsigned long load_bias = 0, phdr_addr = 0;
int first_pt_load = 1;
unsigned long error;
struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
struct elf_phdr *elf_property_phdata = NULL;
unsigned long elf_bss, elf_brk;
int bss_prot = 0;
int retval, i;
unsigned long elf_entry;
unsigned long e_entry;
unsigned long interp_load_addr = 0;
unsigned long start_code, end_code, start_data, end_data;
unsigned long reloc_func_desc __maybe_unused = 0;
int executable_stack = EXSTACK_DEFAULT;
struct elfhdr *elf_ex = (struct elfhdr *)bprm->buf;
struct elfhdr *interp_elf_ex = NULL;
struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
struct mm_struct *mm;
struct pt_regs *regs;
retval = -ENOEXEC;
/* First of all, some simple consistency checks */
if (memcmp(elf_ex->e_ident, ELFMAG, SELFMAG) != 0)
goto out;
if (elf_ex->e_type != ET_EXEC && elf_ex->e_type != ET_DYN)
goto out;
if (!elf_check_arch(elf_ex))
goto out;
if (elf_check_fdpic(elf_ex))
goto out;
if (!bprm->file->f_op->mmap)
goto out;
elf_phdata = load_elf_phdrs(elf_ex, bprm->file);
if (!elf_phdata)
goto out;
elf_ppnt = elf_phdata;
for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++) {
char *elf_interpreter;
if (elf_ppnt->p_type == PT_GNU_PROPERTY) {
elf_property_phdata = elf_ppnt;
continue;
}
if (elf_ppnt->p_type != PT_INTERP)
continue;
/*
* This is the program interpreter used for shared libraries -
* for now assume that this is an a.out format binary.
*/
retval = -ENOEXEC;
if (elf_ppnt->p_filesz > PATH_MAX || elf_ppnt->p_filesz < 2)
goto out_free_ph;
retval = -ENOMEM;
elf_interpreter = kmalloc(elf_ppnt->p_filesz, GFP_KERNEL);
if (!elf_interpreter)
goto out_free_ph;
retval = elf_read(bprm->file, elf_interpreter, elf_ppnt->p_filesz,
elf_ppnt->p_offset);
if (retval < 0)
goto out_free_interp;
/* make sure path is NULL terminated */
retval = -ENOEXEC;
if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
goto out_free_interp;
interpreter = open_exec(elf_interpreter);
kfree(elf_interpreter);
retval = PTR_ERR(interpreter);
if (IS_ERR(interpreter))
goto out_free_ph;
/*
* If the binary is not readable then enforce mm->dumpable = 0
* regardless of the interpreter's permissions.
*/
would_dump(bprm, interpreter);
interp_elf_ex = kmalloc(sizeof(*interp_elf_ex), GFP_KERNEL);
if (!interp_elf_ex) {
retval = -ENOMEM;
goto out_free_file;
}
/* Get the exec headers */
retval = elf_read(interpreter, interp_elf_ex,
sizeof(*interp_elf_ex), 0);
if (retval < 0)
goto out_free_dentry;
break;
out_free_interp:
kfree(elf_interpreter);
goto out_free_ph;
}
elf_ppnt = elf_phdata;
for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++)
switch (elf_ppnt->p_type) {
case PT_GNU_STACK:
if (elf_ppnt->p_flags & PF_X)
executable_stack = EXSTACK_ENABLE_X;
else
executable_stack = EXSTACK_DISABLE_X;
break;
case PT_LOPROC ... PT_HIPROC:
retval = arch_elf_pt_proc(elf_ex, elf_ppnt,
bprm->file, false,
&arch_state);
if (retval)
goto out_free_dentry;
break;
}
/* Some simple consistency checks for the interpreter */
if (interpreter) {
retval = -ELIBBAD;
/* Not an ELF interpreter */
if (memcmp(interp_elf_ex->e_ident, ELFMAG, SELFMAG) != 0)
goto out_free_dentry;
/* Verify the interpreter has a valid arch */
if (!elf_check_arch(interp_elf_ex) ||
elf_check_fdpic(interp_elf_ex))
goto out_free_dentry;
/* Load the interpreter program headers */
interp_elf_phdata = load_elf_phdrs(interp_elf_ex,
interpreter);
if (!interp_elf_phdata)
goto out_free_dentry;
/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
elf_property_phdata = NULL;
elf_ppnt = interp_elf_phdata;
for (i = 0; i < interp_elf_ex->e_phnum; i++, elf_ppnt++)
switch (elf_ppnt->p_type) {
case PT_GNU_PROPERTY:
elf_property_phdata = elf_ppnt;
break;
case PT_LOPROC ... PT_HIPROC:
retval = arch_elf_pt_proc(interp_elf_ex,
elf_ppnt, interpreter,
true, &arch_state);
if (retval)
goto out_free_dentry;
break;
}
}
retval = parse_elf_properties(interpreter ?: bprm->file,
elf_property_phdata, &arch_state);
if (retval)
goto out_free_dentry;
/*
* Allow arch code to reject the ELF at this point, whilst it's
* still possible to return an error to the code that invoked
* the exec syscall.
*/
retval = arch_check_elf(elf_ex,
!!interpreter, interp_elf_ex,
&arch_state);
if (retval)
goto out_free_dentry;
/* Flush all traces of the currently running executable */
retval = begin_new_exec(bprm);
if (retval)
goto out_free_dentry;
/* Do this immediately, since STACK_TOP as used in setup_arg_pages
may depend on the personality. */
SET_PERSONALITY2(*elf_ex, &arch_state);
if (elf_read_implies_exec(*elf_ex, executable_stack))
current->personality |= READ_IMPLIES_EXEC;
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
current->flags |= PF_RANDOMIZE;
setup_new_exec(bprm);
/* Do this so that we can load the interpreter, if need be. We will
change some of these later */
retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
executable_stack);
if (retval < 0)
goto out_free_dentry;
elf_bss = 0;
elf_brk = 0;
start_code = ~0UL;
end_code = 0;
start_data = 0;
end_data = 0;
/* Now we do a little grungy work by mmapping the ELF image into
the correct location in memory. */
for(i = 0, elf_ppnt = elf_phdata;
i < elf_ex->e_phnum; i++, elf_ppnt++) {
int elf_prot, elf_flags;
unsigned long k, vaddr;
unsigned long total_size = 0;
unsigned long alignment;
if (elf_ppnt->p_type != PT_LOAD)
continue;
if (unlikely (elf_brk > elf_bss)) {
unsigned long nbyte;
/* There was a PT_LOAD segment with p_memsz > p_filesz
before this one. Map anonymous pages, if needed,
and clear the area. */
retval = set_brk(elf_bss + load_bias,
elf_brk + load_bias,
bss_prot);
if (retval)
goto out_free_dentry;
nbyte = ELF_PAGEOFFSET(elf_bss);
if (nbyte) {
nbyte = ELF_MIN_ALIGN - nbyte;
if (nbyte > elf_brk - elf_bss)
nbyte = elf_brk - elf_bss;
if (clear_user((void __user *)elf_bss +
load_bias, nbyte)) {
/*
* This bss-zeroing can fail if the ELF
* file specifies odd protections. So
* we don't check the return value
*/
}
}
}
elf_prot = make_prot(elf_ppnt->p_flags, &arch_state,
!!interpreter, false);
elf_flags = MAP_PRIVATE;
vaddr = elf_ppnt->p_vaddr;
/*
* The first time through the loop, first_pt_load is true:
* layout will be calculated. Once set, use MAP_FIXED since
* we know we've already safely mapped the entire region with
* MAP_FIXED_NOREPLACE in the once-per-binary logic following.
*/
if (!first_pt_load) {
elf_flags |= MAP_FIXED;
} else if (elf_ex->e_type == ET_EXEC) {
/*
* This logic is run once for the first LOAD Program
* Header for ET_EXEC binaries. No special handling
* is needed.
*/
elf_flags |= MAP_FIXED_NOREPLACE;
} else if (elf_ex->e_type == ET_DYN) {
/*
* This logic is run once for the first LOAD Program
* Header for ET_DYN binaries to calculate the
* randomization (load_bias) for all the LOAD
* Program Headers.
*
* There are effectively two types of ET_DYN
* binaries: programs (i.e. PIE: ET_DYN with INTERP)
* and loaders (ET_DYN without INTERP, since they
* _are_ the ELF interpreter). The loaders must
* be loaded away from programs since the program
* may otherwise collide with the loader (especially
* for ET_EXEC which does not have a randomized
* position). For example to handle invocations of
* "./ld.so someprog" to test out a new version of
* the loader, the subsequent program that the
* loader loads must avoid the loader itself, so
* they cannot share the same load range. Sufficient
* room for the brk must be allocated with the
* loader as well, since brk must be available with
* the loader.
*
* Therefore, programs are loaded offset from
* ELF_ET_DYN_BASE and loaders are loaded into the
* independently randomized mmap region (0 load_bias
* without MAP_FIXED nor MAP_FIXED_NOREPLACE).
*/
if (interpreter) {
load_bias = ELF_ET_DYN_BASE;
if (current->flags & PF_RANDOMIZE)
load_bias += arch_mmap_rnd();
alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum);
if (alignment)
load_bias &= ~(alignment - 1);
elf_flags |= MAP_FIXED_NOREPLACE;
} else
load_bias = 0;
/*
* Since load_bias is used for all subsequent loading
* calculations, we must lower it by the first vaddr
* so that the remaining calculations based on the
* ELF vaddrs will be correctly offset. The result
* is then page aligned.
*/
load_bias = ELF_PAGESTART(load_bias - vaddr);
/*
* Calculate the entire size of the ELF mapping
* (total_size), used for the initial mapping,
* due to load_addr_set which is set to true later
* once the initial mapping is performed.
*
* Note that this is only sensible when the LOAD
* segments are contiguous (or overlapping). If
* used for LOADs that are far apart, this would
* cause the holes between LOADs to be mapped,
* running the risk of having the mapping fail,
* as it would be larger than the ELF file itself.
*
* As a result, only ET_DYN does this, since
* some ET_EXEC (e.g. ia64) may have large virtual
* memory holes between LOADs.
*
*/
total_size = total_mapping_size(elf_phdata,
elf_ex->e_phnum);
if (!total_size) {
retval = -EINVAL;
goto out_free_dentry;
}
}
error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
elf_prot, elf_flags, total_size);
if (BAD_ADDR(error)) {
retval = IS_ERR_VALUE(error) ?
PTR_ERR((void*)error) : -EINVAL;
goto out_free_dentry;
}
if (first_pt_load) {
first_pt_load = 0;
if (elf_ex->e_type == ET_DYN) {
load_bias += error -
ELF_PAGESTART(load_bias + vaddr);
reloc_func_desc = load_bias;
}
}
/*
* Figure out which segment in the file contains the Program
* Header table, and map to the associated memory address.
*/
if (elf_ppnt->p_offset <= elf_ex->e_phoff &&
elf_ex->e_phoff < elf_ppnt->p_offset + elf_ppnt->p_filesz) {
phdr_addr = elf_ex->e_phoff - elf_ppnt->p_offset +
elf_ppnt->p_vaddr;
}
k = elf_ppnt->p_vaddr;
if ((elf_ppnt->p_flags & PF_X) && k < start_code)
start_code = k;
if (start_data < k)
start_data = k;
/*
* Check to see if the section's size will overflow the
* allowed task size. Note that p_filesz must always be
* <= p_memsz so it is only necessary to check p_memsz.
*/
if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
elf_ppnt->p_memsz > TASK_SIZE ||
TASK_SIZE - elf_ppnt->p_memsz < k) {
/* set_brk can never work. Avoid overflows. */
retval = -EINVAL;
goto out_free_dentry;
}
k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
if (k > elf_bss)
elf_bss = k;
if ((elf_ppnt->p_flags & PF_X) && end_code < k)
end_code = k;
if (end_data < k)
end_data = k;
k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
if (k > elf_brk) {
bss_prot = elf_prot;
elf_brk = k;
}
}
e_entry = elf_ex->e_entry + load_bias;
phdr_addr += load_bias;
elf_bss += load_bias;
elf_brk += load_bias;
start_code += load_bias;
end_code += load_bias;
start_data += load_bias;
end_data += load_bias;
/* Calling set_brk effectively mmaps the pages that we need
* for the bss and break sections. We must do this before
* mapping in the interpreter, to make sure it doesn't wind
* up getting placed where the bss needs to go.
*/
retval = set_brk(elf_bss, elf_brk, bss_prot);
if (retval)
goto out_free_dentry;
if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
retval = -EFAULT; /* Nobody gets to see this, but.. */
goto out_free_dentry;
}
if (interpreter) {
elf_entry = load_elf_interp(interp_elf_ex,
interpreter,
load_bias, interp_elf_phdata,
&arch_state);
if (!IS_ERR_VALUE(elf_entry)) {
/*
* load_elf_interp() returns relocation
* adjustment
*/
interp_load_addr = elf_entry;
elf_entry += interp_elf_ex->e_entry;
}
if (BAD_ADDR(elf_entry)) {
retval = IS_ERR_VALUE(elf_entry) ?
(int)elf_entry : -EINVAL;
goto out_free_dentry;
}
reloc_func_desc = interp_load_addr;
allow_write_access(interpreter);
fput(interpreter);
kfree(interp_elf_ex);
kfree(interp_elf_phdata);
} else {
elf_entry = e_entry;
if (BAD_ADDR(elf_entry)) {
retval = -EINVAL;
goto out_free_dentry;
}
}
kfree(elf_phdata);
set_binfmt(&elf_format);
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
retval = ARCH_SETUP_ADDITIONAL_PAGES(bprm, elf_ex, !!interpreter);
if (retval < 0)
goto out;
#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
retval = create_elf_tables(bprm, elf_ex, interp_load_addr,
e_entry, phdr_addr);
if (retval < 0)
goto out;
mm = current->mm;
mm->end_code = end_code;
mm->start_code = start_code;
mm->start_data = start_data;
mm->end_data = end_data;
mm->start_stack = bprm->p;
if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
/*
* For architectures with ELF randomization, when executing
* a loader directly (i.e. no interpreter listed in ELF
* headers), move the brk area out of the mmap region
* (since it grows up, and may collide early with the stack
* growing down), and into the unused ELF_ET_DYN_BASE region.
*/
if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) &&
elf_ex->e_type == ET_DYN && !interpreter) {
mm->brk = mm->start_brk = ELF_ET_DYN_BASE;
}
mm->brk = mm->start_brk = arch_randomize_brk(mm);
#ifdef compat_brk_randomized
current->brk_randomized = 1;
#endif
}
if (current->personality & MMAP_PAGE_ZERO) {
/* Why this, you ask??? Well SVr4 maps page 0 as read-only,
and some applications "depend" upon this behavior.
Since we do not have the power to recompile these, we
emulate the SVr4 behavior. Sigh. */
error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE, 0);
}
regs = current_pt_regs();
#ifdef ELF_PLAT_INIT
/*
* The ABI may specify that certain registers be set up in special
* ways (on i386 %edx is the address of a DT_FINI function, for
* example. In addition, it may also specify (eg, PowerPC64 ELF)
* that the e_entry field is the address of the function descriptor
* for the startup routine, rather than the address of the startup
* routine itself. This macro performs whatever initialization to
* the regs structure is required as well as any relocations to the
* function descriptor entries when executing dynamically links apps.
*/
ELF_PLAT_INIT(regs, reloc_func_desc);
#endif
finalize_exec(bprm);
START_THREAD(elf_ex, regs, elf_entry, bprm->p);
retval = 0;
out:
return retval;
/* error cleanup */
out_free_dentry:
kfree(interp_elf_ex);
kfree(interp_elf_phdata);
out_free_file:
allow_write_access(interpreter);
if (interpreter)
fput(interpreter);
out_free_ph:
kfree(elf_phdata);
goto out;
}
#ifdef CONFIG_USELIB
/* This is really simpleminded and specialized - we are loading an
a.out library that is given an ELF header. */
static int load_elf_library(struct file *file)
{
struct elf_phdr *elf_phdata;
struct elf_phdr *eppnt;
unsigned long elf_bss, bss, len;
int retval, error, i, j;
struct elfhdr elf_ex;
error = -ENOEXEC;
retval = elf_read(file, &elf_ex, sizeof(elf_ex), 0);
if (retval < 0)
goto out;
if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
goto out;
/* First of all, some simple consistency checks */
if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
!elf_check_arch(&elf_ex) || !file->f_op->mmap)
goto out;
if (elf_check_fdpic(&elf_ex))
goto out;
/* Now read in all of the header information */
j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
/* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
error = -ENOMEM;
elf_phdata = kmalloc(j, GFP_KERNEL);
if (!elf_phdata)
goto out;
eppnt = elf_phdata;
error = -ENOEXEC;
retval = elf_read(file, eppnt, j, elf_ex.e_phoff);
if (retval < 0)
goto out_free_ph;
for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
if ((eppnt + i)->p_type == PT_LOAD)
j++;
if (j != 1)
goto out_free_ph;
while (eppnt->p_type != PT_LOAD)
eppnt++;
/* Now use mmap to map the library into memory. */
error = vm_mmap(file,
ELF_PAGESTART(eppnt->p_vaddr),
(eppnt->p_filesz +
ELF_PAGEOFFSET(eppnt->p_vaddr)),
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_FIXED_NOREPLACE | MAP_PRIVATE,
(eppnt->p_offset -
ELF_PAGEOFFSET(eppnt->p_vaddr)));
if (error != ELF_PAGESTART(eppnt->p_vaddr))
goto out_free_ph;
elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
if (padzero(elf_bss)) {
error = -EFAULT;
goto out_free_ph;
}
len = ELF_PAGEALIGN(eppnt->p_filesz + eppnt->p_vaddr);
bss = ELF_PAGEALIGN(eppnt->p_memsz + eppnt->p_vaddr);
if (bss > len) {
error = vm_brk(len, bss - len);
if (error)
goto out_free_ph;
}
error = 0;
out_free_ph:
kfree(elf_phdata);
out:
return error;
}
#endif /* #ifdef CONFIG_USELIB */
#ifdef CONFIG_ELF_CORE
/*
* ELF core dumper
*
* Modelled on fs/exec.c:aout_core_dump()
* Jeremy Fitzhardinge <[email protected]>
*/
/* An ELF note in memory */
struct memelfnote
{
const char *name;
int type;
unsigned int datasz;
void *data;
};
static int notesize(struct memelfnote *en)
{
int sz;
sz = sizeof(struct elf_note);
sz += roundup(strlen(en->name) + 1, 4);
sz += roundup(en->datasz, 4);
return sz;
}
static int writenote(struct memelfnote *men, struct coredump_params *cprm)
{
struct elf_note en;
en.n_namesz = strlen(men->name) + 1;
en.n_descsz = men->datasz;
en.n_type = men->type;
return dump_emit(cprm, &en, sizeof(en)) &&
dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
}
static void fill_elf_header(struct elfhdr *elf, int segs,
u16 machine, u32 flags)
{
memset(elf, 0, sizeof(*elf));
memcpy(elf->e_ident, ELFMAG, SELFMAG);
elf->e_ident[EI_CLASS] = ELF_CLASS;
elf->e_ident[EI_DATA] = ELF_DATA;
elf->e_ident[EI_VERSION] = EV_CURRENT;
elf->e_ident[EI_OSABI] = ELF_OSABI;
elf->e_type = ET_CORE;
elf->e_machine = machine;
elf->e_version = EV_CURRENT;
elf->e_phoff = sizeof(struct elfhdr);
elf->e_flags = flags;
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
elf->e_phnum = segs;
}
static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
{
phdr->p_type = PT_NOTE;
phdr->p_offset = offset;
phdr->p_vaddr = 0;
phdr->p_paddr = 0;
phdr->p_filesz = sz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
phdr->p_align = 4;
}
static void fill_note(struct memelfnote *note, const char *name, int type,
unsigned int sz, void *data)
{
note->name = name;
note->type = type;
note->datasz = sz;
note->data = data;
}
/*
* fill up all the fields in prstatus from the given task struct, except
* registers which need to be filled up separately.
*/
static void fill_prstatus(struct elf_prstatus_common *prstatus,
struct task_struct *p, long signr)
{
prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
prstatus->pr_sigpend = p->pending.signal.sig[0];
prstatus->pr_sighold = p->blocked.sig[0];
rcu_read_lock();
prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
rcu_read_unlock();
prstatus->pr_pid = task_pid_vnr(p);
prstatus->pr_pgrp = task_pgrp_vnr(p);
prstatus->pr_sid = task_session_vnr(p);
if (thread_group_leader(p)) {
struct task_cputime cputime;
/*
* This is the record for the group leader. It shows the
* group-wide total, not its individual thread total.
*/
thread_group_cputime(p, &cputime);
prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
} else {
u64 utime, stime;
task_cputime(p, &utime, &stime);
prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
}
prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
}
static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
struct mm_struct *mm)
{
const struct cred *cred;
unsigned int i, len;
unsigned int state;
/* first copy the parameters from user space */
memset(psinfo, 0, sizeof(struct elf_prpsinfo));
len = mm->arg_end - mm->arg_start;
if (len >= ELF_PRARGSZ)
len = ELF_PRARGSZ-1;
if (copy_from_user(&psinfo->pr_psargs,
(const char __user *)mm->arg_start, len))
return -EFAULT;
for(i = 0; i < len; i++)
if (psinfo->pr_psargs[i] == 0)
psinfo->pr_psargs[i] = ' ';
psinfo->pr_psargs[len] = 0;
rcu_read_lock();
psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
rcu_read_unlock();
psinfo->pr_pid = task_pid_vnr(p);
psinfo->pr_pgrp = task_pgrp_vnr(p);
psinfo->pr_sid = task_session_vnr(p);
state = READ_ONCE(p->__state);
i = state ? ffz(~state) + 1 : 0;
psinfo->pr_state = i;
psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
psinfo->pr_zomb = psinfo->pr_sname == 'Z';
psinfo->pr_nice = task_nice(p);
psinfo->pr_flag = p->flags;
rcu_read_lock();
cred = __task_cred(p);
SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
rcu_read_unlock();
get_task_comm(psinfo->pr_fname, p);
return 0;
}
static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
{
elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
int i = 0;
do
i += 2;
while (auxv[i - 2] != AT_NULL);
fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
}
static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
const kernel_siginfo_t *siginfo)
{
copy_siginfo_to_external(csigdata, siginfo);
fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
}
#define MAX_FILE_NOTE_SIZE (4*1024*1024)
/*
* Format of NT_FILE note:
*
* long count -- how many files are mapped
* long page_size -- units for file_ofs
* array of [COUNT] elements of
* long start
* long end
* long file_ofs
* followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
*/
static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm)
{
unsigned count, size, names_ofs, remaining, n;
user_long_t *data;
user_long_t *start_end_ofs;
char *name_base, *name_curpos;
int i;
/* *Estimated* file count and total data size needed */
count = cprm->vma_count;
if (count > UINT_MAX / 64)
return -EINVAL;
size = count * 64;
names_ofs = (2 + 3 * count) * sizeof(data[0]);
alloc:
if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */
return -EINVAL;
size = round_up(size, PAGE_SIZE);
/*
* "size" can be 0 here legitimately.
* Let it ENOMEM and omit NT_FILE section which will be empty anyway.
*/
data = kvmalloc(size, GFP_KERNEL);
if (ZERO_OR_NULL_PTR(data))
return -ENOMEM;
start_end_ofs = data + 2;
name_base = name_curpos = ((char *)data) + names_ofs;
remaining = size - names_ofs;
count = 0;
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *m = &cprm->vma_meta[i];
struct file *file;
const char *filename;
file = m->file;
if (!file)
continue;
filename = file_path(file, name_curpos, remaining);
if (IS_ERR(filename)) {
if (PTR_ERR(filename) == -ENAMETOOLONG) {
kvfree(data);
size = size * 5 / 4;
goto alloc;
}
continue;
}
/* file_path() fills at the end, move name down */
/* n = strlen(filename) + 1: */
n = (name_curpos + remaining) - filename;
remaining = filename - name_curpos;
memmove(name_curpos, filename, n);
name_curpos += n;
*start_end_ofs++ = m->start;
*start_end_ofs++ = m->end;
*start_end_ofs++ = m->pgoff;
count++;
}
/* Now we know exact count of files, can store it */
data[0] = count;
data[1] = PAGE_SIZE;
/*
* Count usually is less than mm->map_count,
* we need to move filenames down.
*/
n = cprm->vma_count - count;
if (n != 0) {
unsigned shift_bytes = n * 3 * sizeof(data[0]);
memmove(name_base - shift_bytes, name_base,
name_curpos - name_base);
name_curpos -= shift_bytes;
}
size = name_curpos - (char *)data;
fill_note(note, "CORE", NT_FILE, size, data);
return 0;
}
#include <linux/regset.h>
struct elf_thread_core_info {
struct elf_thread_core_info *next;
struct task_struct *task;
struct elf_prstatus prstatus;
struct memelfnote notes[];
};
struct elf_note_info {
struct elf_thread_core_info *thread;
struct memelfnote psinfo;
struct memelfnote signote;
struct memelfnote auxv;
struct memelfnote files;
user_siginfo_t csigdata;
size_t size;
int thread_notes;
};
#ifdef CORE_DUMP_USE_REGSET
/*
* When a regset has a writeback hook, we call it on each thread before
* dumping user memory. On register window machines, this makes sure the
* user memory backing the register data is up to date before we read it.
*/
static void do_thread_regset_writeback(struct task_struct *task,
const struct user_regset *regset)
{
if (regset->writeback)
regset->writeback(task, regset, 1);
}
#ifndef PRSTATUS_SIZE
#define PRSTATUS_SIZE sizeof(struct elf_prstatus)
#endif
#ifndef SET_PR_FPVALID
#define SET_PR_FPVALID(S) ((S)->pr_fpvalid = 1)
#endif
static int fill_thread_core_info(struct elf_thread_core_info *t,
const struct user_regset_view *view,
long signr, struct elf_note_info *info)
{
unsigned int note_iter, view_iter;
/*
* NT_PRSTATUS is the one special case, because the regset data
* goes into the pr_reg field inside the note contents, rather
* than being the whole note contents. We fill the regset in here.
* We assume that regset 0 is NT_PRSTATUS.
*/
fill_prstatus(&t->prstatus.common, t->task, signr);
regset_get(t->task, &view->regsets[0],
sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
PRSTATUS_SIZE, &t->prstatus);
info->size += notesize(&t->notes[0]);
do_thread_regset_writeback(t->task, &view->regsets[0]);
/*
* Each other regset might generate a note too. For each regset
* that has no core_note_type or is inactive, skip it.
*/
note_iter = 1;
for (view_iter = 1; view_iter < view->n; ++view_iter) {
const struct user_regset *regset = &view->regsets[view_iter];
int note_type = regset->core_note_type;
bool is_fpreg = note_type == NT_PRFPREG;
void *data;
int ret;
do_thread_regset_writeback(t->task, regset);
if (!note_type) // not for coredumps
continue;
if (regset->active && regset->active(t->task, regset) <= 0)
continue;
ret = regset_get_alloc(t->task, regset, ~0U, &data);
if (ret < 0)
continue;
if (WARN_ON_ONCE(note_iter >= info->thread_notes))
break;
if (is_fpreg)
SET_PR_FPVALID(&t->prstatus);
fill_note(&t->notes[note_iter], is_fpreg ? "CORE" : "LINUX",
note_type, ret, data);
info->size += notesize(&t->notes[note_iter]);
note_iter++;
}
return 1;
}
#else
static int fill_thread_core_info(struct elf_thread_core_info *t,
const struct user_regset_view *view,
long signr, struct elf_note_info *info)
{
struct task_struct *p = t->task;
elf_fpregset_t *fpu;
fill_prstatus(&t->prstatus.common, p, signr);
elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
&(t->prstatus));
info->size += notesize(&t->notes[0]);
fpu = kzalloc(sizeof(elf_fpregset_t), GFP_KERNEL);
if (!fpu || !elf_core_copy_task_fpregs(p, fpu)) {
kfree(fpu);
return 1;
}
t->prstatus.pr_fpvalid = 1;
fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
info->size += notesize(&t->notes[1]);
return 1;
}
#endif
static int fill_note_info(struct elfhdr *elf, int phdrs,
struct elf_note_info *info,
struct coredump_params *cprm)
{
struct task_struct *dump_task = current;
const struct user_regset_view *view;
struct elf_thread_core_info *t;
struct elf_prpsinfo *psinfo;
struct core_thread *ct;
psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
if (!psinfo)
return 0;
fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
#ifdef CORE_DUMP_USE_REGSET
view = task_user_regset_view(dump_task);
/*
* Figure out how many notes we're going to need for each thread.
*/
info->thread_notes = 0;
for (int i = 0; i < view->n; ++i)
if (view->regsets[i].core_note_type != 0)
++info->thread_notes;
/*
* Sanity check. We rely on regset 0 being in NT_PRSTATUS,
* since it is our one special case.
*/
if (unlikely(info->thread_notes == 0) ||
unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
WARN_ON(1);
return 0;
}
/*
* Initialize the ELF file header.
*/
fill_elf_header(elf, phdrs,
view->e_machine, view->e_flags);
#else
view = NULL;
info->thread_notes = 2;
fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS);
#endif
/*
* Allocate a structure for each thread.
*/
info->thread = kzalloc(offsetof(struct elf_thread_core_info,
notes[info->thread_notes]),
GFP_KERNEL);
if (unlikely(!info->thread))
return 0;
info->thread->task = dump_task;
for (ct = dump_task->signal->core_state->dumper.next; ct; ct = ct->next) {
t = kzalloc(offsetof(struct elf_thread_core_info,
notes[info->thread_notes]),
GFP_KERNEL);
if (unlikely(!t))
return 0;
t->task = ct->task;
t->next = info->thread->next;
info->thread->next = t;
}
/*
* Now fill in each thread's information.
*/
for (t = info->thread; t != NULL; t = t->next)
if (!fill_thread_core_info(t, view, cprm->siginfo->si_signo, info))
return 0;
/*
* Fill in the two process-wide notes.
*/
fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
info->size += notesize(&info->psinfo);
fill_siginfo_note(&info->signote, &info->csigdata, cprm->siginfo);
info->size += notesize(&info->signote);
fill_auxv_note(&info->auxv, current->mm);
info->size += notesize(&info->auxv);
if (fill_files_note(&info->files, cprm) == 0)
info->size += notesize(&info->files);
return 1;
}
/*
* Write all the notes for each thread. When writing the first thread, the
* process-wide notes are interleaved after the first thread-specific note.
*/
static int write_note_info(struct elf_note_info *info,
struct coredump_params *cprm)
{
bool first = true;
struct elf_thread_core_info *t = info->thread;
do {
int i;
if (!writenote(&t->notes[0], cprm))
return 0;
if (first && !writenote(&info->psinfo, cprm))
return 0;
if (first && !writenote(&info->signote, cprm))
return 0;
if (first && !writenote(&info->auxv, cprm))
return 0;
if (first && info->files.data &&
!writenote(&info->files, cprm))
return 0;
for (i = 1; i < info->thread_notes; ++i)
if (t->notes[i].data &&
!writenote(&t->notes[i], cprm))
return 0;
first = false;
t = t->next;
} while (t);
return 1;
}
static void free_note_info(struct elf_note_info *info)
{
struct elf_thread_core_info *threads = info->thread;
while (threads) {
unsigned int i;
struct elf_thread_core_info *t = threads;
threads = t->next;
WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
for (i = 1; i < info->thread_notes; ++i)
kfree(t->notes[i].data);
kfree(t);
}
kfree(info->psinfo.data);
kvfree(info->files.data);
}
static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
elf_addr_t e_shoff, int segs)
{
elf->e_shoff = e_shoff;
elf->e_shentsize = sizeof(*shdr4extnum);
elf->e_shnum = 1;
elf->e_shstrndx = SHN_UNDEF;
memset(shdr4extnum, 0, sizeof(*shdr4extnum));
shdr4extnum->sh_type = SHT_NULL;
shdr4extnum->sh_size = elf->e_shnum;
shdr4extnum->sh_link = elf->e_shstrndx;
shdr4extnum->sh_info = segs;
}
/*
* Actual dumper
*
* This is a two-pass process; first we find the offsets of the bits,
* and then they are actually written out. If we run out of core limit
* we just truncate.
*/
static int elf_core_dump(struct coredump_params *cprm)
{
int has_dumped = 0;
int segs, i;
struct elfhdr elf;
loff_t offset = 0, dataoff;
struct elf_note_info info = { };
struct elf_phdr *phdr4note = NULL;
struct elf_shdr *shdr4extnum = NULL;
Elf_Half e_phnum;
elf_addr_t e_shoff;
/*
* The number of segs are recored into ELF header as 16bit value.
* Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
*/
segs = cprm->vma_count + elf_core_extra_phdrs(cprm);
/* for notes section */
segs++;
/* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
* this, kernel supports extended numbering. Have a look at
* include/linux/elf.h for further information. */
e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
/*
* Collect all the non-memory information about the process for the
* notes. This also sets up the file header.
*/
if (!fill_note_info(&elf, e_phnum, &info, cprm))
goto end_coredump;
has_dumped = 1;
offset += sizeof(elf); /* ELF header */
offset += segs * sizeof(struct elf_phdr); /* Program headers */
/* Write notes phdr entry */
{
size_t sz = info.size;
/* For cell spufs */
sz += elf_coredump_extra_notes_size();
phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
if (!phdr4note)
goto end_coredump;
fill_elf_note_phdr(phdr4note, sz, offset);
offset += sz;
}
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
offset += cprm->vma_data_size;
offset += elf_core_extra_data_size(cprm);
e_shoff = offset;
if (e_phnum == PN_XNUM) {
shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
if (!shdr4extnum)
goto end_coredump;
fill_extnum_info(&elf, shdr4extnum, e_shoff, segs);
}
offset = dataoff;
if (!dump_emit(cprm, &elf, sizeof(elf)))
goto end_coredump;
if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
goto end_coredump;
/* Write program headers for segments dump */
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *meta = cprm->vma_meta + i;
struct elf_phdr phdr;
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
phdr.p_vaddr = meta->start;
phdr.p_paddr = 0;
phdr.p_filesz = meta->dump_size;
phdr.p_memsz = meta->end - meta->start;
offset += phdr.p_filesz;
phdr.p_flags = 0;
if (meta->flags & VM_READ)
phdr.p_flags |= PF_R;
if (meta->flags & VM_WRITE)
phdr.p_flags |= PF_W;
if (meta->flags & VM_EXEC)
phdr.p_flags |= PF_X;
phdr.p_align = ELF_EXEC_PAGESIZE;
if (!dump_emit(cprm, &phdr, sizeof(phdr)))
goto end_coredump;
}
if (!elf_core_write_extra_phdrs(cprm, offset))
goto end_coredump;
/* write out the notes section */
if (!write_note_info(&info, cprm))
goto end_coredump;
/* For cell spufs */
if (elf_coredump_extra_notes_write(cprm))
goto end_coredump;
/* Align to page */
dump_skip_to(cprm, dataoff);
for (i = 0; i < cprm->vma_count; i++) {
struct core_vma_metadata *meta = cprm->vma_meta + i;
if (!dump_user_range(cprm, meta->start, meta->dump_size))
goto end_coredump;
}
if (!elf_core_write_extra_data(cprm))
goto end_coredump;
if (e_phnum == PN_XNUM) {
if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
goto end_coredump;
}
end_coredump:
free_note_info(&info);
kfree(shdr4extnum);
kfree(phdr4note);
return has_dumped;
}
#endif /* CONFIG_ELF_CORE */
static int __init init_elf_binfmt(void)
{
register_binfmt(&elf_format);
return 0;
}
static void __exit exit_elf_binfmt(void)
{
/* Remove the COFF and ELF loaders. */
unregister_binfmt(&elf_format);
}
core_initcall(init_elf_binfmt);
module_exit(exit_elf_binfmt);
#ifdef CONFIG_BINFMT_ELF_KUNIT_TEST
#include "binfmt_elf_test.c"
#endif
| linux-master | fs/binfmt_elf.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/list_bl.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/workqueue.h>
#include <linux/mbcache.h>
/*
* Mbcache is a simple key-value store. Keys need not be unique, however
* key-value pairs are expected to be unique (we use this fact in
* mb_cache_entry_delete_or_get()).
*
* Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
* Ext4 also uses it for deduplication of xattr values stored in inodes.
* They use hash of data as a key and provide a value that may represent a
* block or inode number. That's why keys need not be unique (hash of different
* data may be the same). However user provided value always uniquely
* identifies a cache entry.
*
* We provide functions for creation and removal of entries, search by key,
* and a special "delete entry with given key-value pair" operation. Fixed
* size hash table is used for fast key lookups.
*/
struct mb_cache {
/* Hash table of entries */
struct hlist_bl_head *c_hash;
/* log2 of hash table size */
int c_bucket_bits;
/* Maximum entries in cache to avoid degrading hash too much */
unsigned long c_max_entries;
/* Protects c_list, c_entry_count */
spinlock_t c_list_lock;
struct list_head c_list;
/* Number of entries in cache */
unsigned long c_entry_count;
struct shrinker c_shrink;
/* Work for shrinking when the cache has too many entries */
struct work_struct c_shrink_work;
};
static struct kmem_cache *mb_entry_cache;
static unsigned long mb_cache_shrink(struct mb_cache *cache,
unsigned long nr_to_scan);
static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,
u32 key)
{
return &cache->c_hash[hash_32(key, cache->c_bucket_bits)];
}
/*
* Number of entries to reclaim synchronously when there are too many entries
* in cache
*/
#define SYNC_SHRINK_BATCH 64
/*
* mb_cache_entry_create - create entry in cache
* @cache - cache where the entry should be created
* @mask - gfp mask with which the entry should be allocated
* @key - key of the entry
* @value - value of the entry
* @reusable - is the entry reusable by others?
*
* Creates entry in @cache with key @key and value @value. The function returns
* -EBUSY if entry with the same key and value already exists in cache.
* Otherwise 0 is returned.
*/
int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
u64 value, bool reusable)
{
struct mb_cache_entry *entry, *dup;
struct hlist_bl_node *dup_node;
struct hlist_bl_head *head;
/* Schedule background reclaim if there are too many entries */
if (cache->c_entry_count >= cache->c_max_entries)
schedule_work(&cache->c_shrink_work);
/* Do some sync reclaim if background reclaim cannot keep up */
if (cache->c_entry_count >= 2*cache->c_max_entries)
mb_cache_shrink(cache, SYNC_SHRINK_BATCH);
entry = kmem_cache_alloc(mb_entry_cache, mask);
if (!entry)
return -ENOMEM;
INIT_LIST_HEAD(&entry->e_list);
/*
* We create entry with two references. One reference is kept by the
* hash table, the other reference is used to protect us from
* mb_cache_entry_delete_or_get() until the entry is fully setup. This
* avoids nesting of cache->c_list_lock into hash table bit locks which
* is problematic for RT.
*/
atomic_set(&entry->e_refcnt, 2);
entry->e_key = key;
entry->e_value = value;
entry->e_flags = 0;
if (reusable)
set_bit(MBE_REUSABLE_B, &entry->e_flags);
head = mb_cache_entry_head(cache, key);
hlist_bl_lock(head);
hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) {
if (dup->e_key == key && dup->e_value == value) {
hlist_bl_unlock(head);
kmem_cache_free(mb_entry_cache, entry);
return -EBUSY;
}
}
hlist_bl_add_head(&entry->e_hash_list, head);
hlist_bl_unlock(head);
spin_lock(&cache->c_list_lock);
list_add_tail(&entry->e_list, &cache->c_list);
cache->c_entry_count++;
spin_unlock(&cache->c_list_lock);
mb_cache_entry_put(cache, entry);
return 0;
}
EXPORT_SYMBOL(mb_cache_entry_create);
void __mb_cache_entry_free(struct mb_cache *cache, struct mb_cache_entry *entry)
{
struct hlist_bl_head *head;
head = mb_cache_entry_head(cache, entry->e_key);
hlist_bl_lock(head);
hlist_bl_del(&entry->e_hash_list);
hlist_bl_unlock(head);
kmem_cache_free(mb_entry_cache, entry);
}
EXPORT_SYMBOL(__mb_cache_entry_free);
/*
* mb_cache_entry_wait_unused - wait to be the last user of the entry
*
* @entry - entry to work on
*
* Wait to be the last user of the entry.
*/
void mb_cache_entry_wait_unused(struct mb_cache_entry *entry)
{
wait_var_event(&entry->e_refcnt, atomic_read(&entry->e_refcnt) <= 2);
}
EXPORT_SYMBOL(mb_cache_entry_wait_unused);
static struct mb_cache_entry *__entry_find(struct mb_cache *cache,
struct mb_cache_entry *entry,
u32 key)
{
struct mb_cache_entry *old_entry = entry;
struct hlist_bl_node *node;
struct hlist_bl_head *head;
head = mb_cache_entry_head(cache, key);
hlist_bl_lock(head);
if (entry && !hlist_bl_unhashed(&entry->e_hash_list))
node = entry->e_hash_list.next;
else
node = hlist_bl_first(head);
while (node) {
entry = hlist_bl_entry(node, struct mb_cache_entry,
e_hash_list);
if (entry->e_key == key &&
test_bit(MBE_REUSABLE_B, &entry->e_flags) &&
atomic_inc_not_zero(&entry->e_refcnt))
goto out;
node = node->next;
}
entry = NULL;
out:
hlist_bl_unlock(head);
if (old_entry)
mb_cache_entry_put(cache, old_entry);
return entry;
}
/*
* mb_cache_entry_find_first - find the first reusable entry with the given key
* @cache: cache where we should search
* @key: key to look for
*
* Search in @cache for a reusable entry with key @key. Grabs reference to the
* first reusable entry found and returns the entry.
*/
struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
u32 key)
{
return __entry_find(cache, NULL, key);
}
EXPORT_SYMBOL(mb_cache_entry_find_first);
/*
* mb_cache_entry_find_next - find next reusable entry with the same key
* @cache: cache where we should search
* @entry: entry to start search from
*
* Finds next reusable entry in the hash chain which has the same key as @entry.
* If @entry is unhashed (which can happen when deletion of entry races with the
* search), finds the first reusable entry in the hash chain. The function drops
* reference to @entry and returns with a reference to the found entry.
*/
struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
struct mb_cache_entry *entry)
{
return __entry_find(cache, entry, entry->e_key);
}
EXPORT_SYMBOL(mb_cache_entry_find_next);
/*
* mb_cache_entry_get - get a cache entry by value (and key)
* @cache - cache we work with
* @key - key
* @value - value
*/
struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
u64 value)
{
struct hlist_bl_node *node;
struct hlist_bl_head *head;
struct mb_cache_entry *entry;
head = mb_cache_entry_head(cache, key);
hlist_bl_lock(head);
hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
if (entry->e_key == key && entry->e_value == value &&
atomic_inc_not_zero(&entry->e_refcnt))
goto out;
}
entry = NULL;
out:
hlist_bl_unlock(head);
return entry;
}
EXPORT_SYMBOL(mb_cache_entry_get);
/* mb_cache_entry_delete_or_get - remove a cache entry if it has no users
* @cache - cache we work with
* @key - key
* @value - value
*
* Remove entry from cache @cache with key @key and value @value. The removal
* happens only if the entry is unused. The function returns NULL in case the
* entry was successfully removed or there's no entry in cache. Otherwise the
* function grabs reference of the entry that we failed to delete because it
* still has users and return it.
*/
struct mb_cache_entry *mb_cache_entry_delete_or_get(struct mb_cache *cache,
u32 key, u64 value)
{
struct mb_cache_entry *entry;
entry = mb_cache_entry_get(cache, key, value);
if (!entry)
return NULL;
/*
* Drop the ref we got from mb_cache_entry_get() and the initial hash
* ref if we are the last user
*/
if (atomic_cmpxchg(&entry->e_refcnt, 2, 0) != 2)
return entry;
spin_lock(&cache->c_list_lock);
if (!list_empty(&entry->e_list))
list_del_init(&entry->e_list);
cache->c_entry_count--;
spin_unlock(&cache->c_list_lock);
__mb_cache_entry_free(cache, entry);
return NULL;
}
EXPORT_SYMBOL(mb_cache_entry_delete_or_get);
/* mb_cache_entry_touch - cache entry got used
* @cache - cache the entry belongs to
* @entry - entry that got used
*
* Marks entry as used to give hit higher chances of surviving in cache.
*/
void mb_cache_entry_touch(struct mb_cache *cache,
struct mb_cache_entry *entry)
{
set_bit(MBE_REFERENCED_B, &entry->e_flags);
}
EXPORT_SYMBOL(mb_cache_entry_touch);
static unsigned long mb_cache_count(struct shrinker *shrink,
struct shrink_control *sc)
{
struct mb_cache *cache = container_of(shrink, struct mb_cache,
c_shrink);
return cache->c_entry_count;
}
/* Shrink number of entries in cache */
static unsigned long mb_cache_shrink(struct mb_cache *cache,
unsigned long nr_to_scan)
{
struct mb_cache_entry *entry;
unsigned long shrunk = 0;
spin_lock(&cache->c_list_lock);
while (nr_to_scan-- && !list_empty(&cache->c_list)) {
entry = list_first_entry(&cache->c_list,
struct mb_cache_entry, e_list);
/* Drop initial hash reference if there is no user */
if (test_bit(MBE_REFERENCED_B, &entry->e_flags) ||
atomic_cmpxchg(&entry->e_refcnt, 1, 0) != 1) {
clear_bit(MBE_REFERENCED_B, &entry->e_flags);
list_move_tail(&entry->e_list, &cache->c_list);
continue;
}
list_del_init(&entry->e_list);
cache->c_entry_count--;
spin_unlock(&cache->c_list_lock);
__mb_cache_entry_free(cache, entry);
shrunk++;
cond_resched();
spin_lock(&cache->c_list_lock);
}
spin_unlock(&cache->c_list_lock);
return shrunk;
}
static unsigned long mb_cache_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
struct mb_cache *cache = container_of(shrink, struct mb_cache,
c_shrink);
return mb_cache_shrink(cache, sc->nr_to_scan);
}
/* We shrink 1/X of the cache when we have too many entries in it */
#define SHRINK_DIVISOR 16
static void mb_cache_shrink_worker(struct work_struct *work)
{
struct mb_cache *cache = container_of(work, struct mb_cache,
c_shrink_work);
mb_cache_shrink(cache, cache->c_max_entries / SHRINK_DIVISOR);
}
/*
* mb_cache_create - create cache
* @bucket_bits: log2 of the hash table size
*
* Create cache for keys with 2^bucket_bits hash entries.
*/
struct mb_cache *mb_cache_create(int bucket_bits)
{
struct mb_cache *cache;
unsigned long bucket_count = 1UL << bucket_bits;
unsigned long i;
cache = kzalloc(sizeof(struct mb_cache), GFP_KERNEL);
if (!cache)
goto err_out;
cache->c_bucket_bits = bucket_bits;
cache->c_max_entries = bucket_count << 4;
INIT_LIST_HEAD(&cache->c_list);
spin_lock_init(&cache->c_list_lock);
cache->c_hash = kmalloc_array(bucket_count,
sizeof(struct hlist_bl_head),
GFP_KERNEL);
if (!cache->c_hash) {
kfree(cache);
goto err_out;
}
for (i = 0; i < bucket_count; i++)
INIT_HLIST_BL_HEAD(&cache->c_hash[i]);
cache->c_shrink.count_objects = mb_cache_count;
cache->c_shrink.scan_objects = mb_cache_scan;
cache->c_shrink.seeks = DEFAULT_SEEKS;
if (register_shrinker(&cache->c_shrink, "mbcache-shrinker")) {
kfree(cache->c_hash);
kfree(cache);
goto err_out;
}
INIT_WORK(&cache->c_shrink_work, mb_cache_shrink_worker);
return cache;
err_out:
return NULL;
}
EXPORT_SYMBOL(mb_cache_create);
/*
* mb_cache_destroy - destroy cache
* @cache: the cache to destroy
*
* Free all entries in cache and cache itself. Caller must make sure nobody
* (except shrinker) can reach @cache when calling this.
*/
void mb_cache_destroy(struct mb_cache *cache)
{
struct mb_cache_entry *entry, *next;
unregister_shrinker(&cache->c_shrink);
/*
* We don't bother with any locking. Cache must not be used at this
* point.
*/
list_for_each_entry_safe(entry, next, &cache->c_list, e_list) {
list_del(&entry->e_list);
WARN_ON(atomic_read(&entry->e_refcnt) != 1);
mb_cache_entry_put(cache, entry);
}
kfree(cache->c_hash);
kfree(cache);
}
EXPORT_SYMBOL(mb_cache_destroy);
static int __init mbcache_init(void)
{
mb_entry_cache = kmem_cache_create("mbcache",
sizeof(struct mb_cache_entry), 0,
SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL);
if (!mb_entry_cache)
return -ENOMEM;
return 0;
}
static void __exit mbcache_exit(void)
{
kmem_cache_destroy(mb_entry_cache);
}
module_init(mbcache_init)
module_exit(mbcache_exit)
MODULE_AUTHOR("Jan Kara <[email protected]>");
MODULE_DESCRIPTION("Meta block cache (for extended attributes)");
MODULE_LICENSE("GPL");
| linux-master | fs/mbcache.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* Provide a way to create a superblock configuration context within the kernel
* that allows a superblock to be set up prior to mounting.
*
* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/magic.h>
#include <linux/security.h>
#include <linux/mnt_namespace.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include <net/net_namespace.h>
#include <asm/sections.h>
#include "mount.h"
#include "internal.h"
enum legacy_fs_param {
LEGACY_FS_UNSET_PARAMS,
LEGACY_FS_MONOLITHIC_PARAMS,
LEGACY_FS_INDIVIDUAL_PARAMS,
};
struct legacy_fs_context {
char *legacy_data; /* Data page for legacy filesystems */
size_t data_size;
enum legacy_fs_param param_type;
};
static int legacy_init_fs_context(struct fs_context *fc);
static const struct constant_table common_set_sb_flag[] = {
{ "dirsync", SB_DIRSYNC },
{ "lazytime", SB_LAZYTIME },
{ "mand", SB_MANDLOCK },
{ "ro", SB_RDONLY },
{ "sync", SB_SYNCHRONOUS },
{ },
};
static const struct constant_table common_clear_sb_flag[] = {
{ "async", SB_SYNCHRONOUS },
{ "nolazytime", SB_LAZYTIME },
{ "nomand", SB_MANDLOCK },
{ "rw", SB_RDONLY },
{ },
};
/*
* Check for a common mount option that manipulates s_flags.
*/
static int vfs_parse_sb_flag(struct fs_context *fc, const char *key)
{
unsigned int token;
token = lookup_constant(common_set_sb_flag, key, 0);
if (token) {
fc->sb_flags |= token;
fc->sb_flags_mask |= token;
return 0;
}
token = lookup_constant(common_clear_sb_flag, key, 0);
if (token) {
fc->sb_flags &= ~token;
fc->sb_flags_mask |= token;
return 0;
}
return -ENOPARAM;
}
/**
* vfs_parse_fs_param_source - Handle setting "source" via parameter
* @fc: The filesystem context to modify
* @param: The parameter
*
* This is a simple helper for filesystems to verify that the "source" they
* accept is sane.
*
* Returns 0 on success, -ENOPARAM if this is not "source" parameter, and
* -EINVAL otherwise. In the event of failure, supplementary error information
* is logged.
*/
int vfs_parse_fs_param_source(struct fs_context *fc, struct fs_parameter *param)
{
if (strcmp(param->key, "source") != 0)
return -ENOPARAM;
if (param->type != fs_value_is_string)
return invalf(fc, "Non-string source");
if (fc->source)
return invalf(fc, "Multiple sources");
fc->source = param->string;
param->string = NULL;
return 0;
}
EXPORT_SYMBOL(vfs_parse_fs_param_source);
/**
* vfs_parse_fs_param - Add a single parameter to a superblock config
* @fc: The filesystem context to modify
* @param: The parameter
*
* A single mount option in string form is applied to the filesystem context
* being set up. Certain standard options (for example "ro") are translated
* into flag bits without going to the filesystem. The active security module
* is allowed to observe and poach options. Any other options are passed over
* to the filesystem to parse.
*
* This may be called multiple times for a context.
*
* Returns 0 on success and a negative error code on failure. In the event of
* failure, supplementary error information may have been set.
*/
int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param)
{
int ret;
if (!param->key)
return invalf(fc, "Unnamed parameter\n");
ret = vfs_parse_sb_flag(fc, param->key);
if (ret != -ENOPARAM)
return ret;
ret = security_fs_context_parse_param(fc, param);
if (ret != -ENOPARAM)
/* Param belongs to the LSM or is disallowed by the LSM; so
* don't pass to the FS.
*/
return ret;
if (fc->ops->parse_param) {
ret = fc->ops->parse_param(fc, param);
if (ret != -ENOPARAM)
return ret;
}
/* If the filesystem doesn't take any arguments, give it the
* default handling of source.
*/
ret = vfs_parse_fs_param_source(fc, param);
if (ret != -ENOPARAM)
return ret;
return invalf(fc, "%s: Unknown parameter '%s'",
fc->fs_type->name, param->key);
}
EXPORT_SYMBOL(vfs_parse_fs_param);
/**
* vfs_parse_fs_string - Convenience function to just parse a string.
* @fc: Filesystem context.
* @key: Parameter name.
* @value: Default value.
* @v_size: Maximum number of bytes in the value.
*/
int vfs_parse_fs_string(struct fs_context *fc, const char *key,
const char *value, size_t v_size)
{
int ret;
struct fs_parameter param = {
.key = key,
.type = fs_value_is_flag,
.size = v_size,
};
if (value) {
param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
if (!param.string)
return -ENOMEM;
param.type = fs_value_is_string;
}
ret = vfs_parse_fs_param(fc, ¶m);
kfree(param.string);
return ret;
}
EXPORT_SYMBOL(vfs_parse_fs_string);
/**
* generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
* @fc: The superblock configuration to fill in.
* @data: The data to parse
*
* Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
* called from the ->monolithic_mount_data() fs_context operation.
*
* Returns 0 on success or the error returned by the ->parse_option() fs_context
* operation on failure.
*/
int generic_parse_monolithic(struct fs_context *fc, void *data)
{
char *options = data, *key;
int ret = 0;
if (!options)
return 0;
ret = security_sb_eat_lsm_opts(options, &fc->security);
if (ret)
return ret;
while ((key = strsep(&options, ",")) != NULL) {
if (*key) {
size_t v_len = 0;
char *value = strchr(key, '=');
if (value) {
if (value == key)
continue;
*value++ = 0;
v_len = strlen(value);
}
ret = vfs_parse_fs_string(fc, key, value, v_len);
if (ret < 0)
break;
}
}
return ret;
}
EXPORT_SYMBOL(generic_parse_monolithic);
/**
* alloc_fs_context - Create a filesystem context.
* @fs_type: The filesystem type.
* @reference: The dentry from which this one derives (or NULL)
* @sb_flags: Filesystem/superblock flags (SB_*)
* @sb_flags_mask: Applicable members of @sb_flags
* @purpose: The purpose that this configuration shall be used for.
*
* Open a filesystem and create a mount context. The mount context is
* initialised with the supplied flags and, if a submount/automount from
* another superblock (referred to by @reference) is supplied, may have
* parameters such as namespaces copied across from that superblock.
*/
static struct fs_context *alloc_fs_context(struct file_system_type *fs_type,
struct dentry *reference,
unsigned int sb_flags,
unsigned int sb_flags_mask,
enum fs_context_purpose purpose)
{
int (*init_fs_context)(struct fs_context *);
struct fs_context *fc;
int ret = -ENOMEM;
fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL_ACCOUNT);
if (!fc)
return ERR_PTR(-ENOMEM);
fc->purpose = purpose;
fc->sb_flags = sb_flags;
fc->sb_flags_mask = sb_flags_mask;
fc->fs_type = get_filesystem(fs_type);
fc->cred = get_current_cred();
fc->net_ns = get_net(current->nsproxy->net_ns);
fc->log.prefix = fs_type->name;
mutex_init(&fc->uapi_mutex);
switch (purpose) {
case FS_CONTEXT_FOR_MOUNT:
fc->user_ns = get_user_ns(fc->cred->user_ns);
break;
case FS_CONTEXT_FOR_SUBMOUNT:
fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
break;
case FS_CONTEXT_FOR_RECONFIGURE:
atomic_inc(&reference->d_sb->s_active);
fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
fc->root = dget(reference);
break;
}
/* TODO: Make all filesystems support this unconditionally */
init_fs_context = fc->fs_type->init_fs_context;
if (!init_fs_context)
init_fs_context = legacy_init_fs_context;
ret = init_fs_context(fc);
if (ret < 0)
goto err_fc;
fc->need_free = true;
return fc;
err_fc:
put_fs_context(fc);
return ERR_PTR(ret);
}
struct fs_context *fs_context_for_mount(struct file_system_type *fs_type,
unsigned int sb_flags)
{
return alloc_fs_context(fs_type, NULL, sb_flags, 0,
FS_CONTEXT_FOR_MOUNT);
}
EXPORT_SYMBOL(fs_context_for_mount);
struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
unsigned int sb_flags,
unsigned int sb_flags_mask)
{
return alloc_fs_context(dentry->d_sb->s_type, dentry, sb_flags,
sb_flags_mask, FS_CONTEXT_FOR_RECONFIGURE);
}
EXPORT_SYMBOL(fs_context_for_reconfigure);
/**
* fs_context_for_submount: allocate a new fs_context for a submount
* @type: file_system_type of the new context
* @reference: reference dentry from which to copy relevant info
*
* Allocate a new fs_context suitable for a submount. This also ensures that
* the fc->security object is inherited from @reference (if needed).
*/
struct fs_context *fs_context_for_submount(struct file_system_type *type,
struct dentry *reference)
{
struct fs_context *fc;
int ret;
fc = alloc_fs_context(type, reference, 0, 0, FS_CONTEXT_FOR_SUBMOUNT);
if (IS_ERR(fc))
return fc;
ret = security_fs_context_submount(fc, reference->d_sb);
if (ret) {
put_fs_context(fc);
return ERR_PTR(ret);
}
return fc;
}
EXPORT_SYMBOL(fs_context_for_submount);
void fc_drop_locked(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
dput(fc->root);
fc->root = NULL;
deactivate_locked_super(sb);
}
static void legacy_fs_context_free(struct fs_context *fc);
/**
* vfs_dup_fs_context - Duplicate a filesystem context.
* @src_fc: The context to copy.
*/
struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
{
struct fs_context *fc;
int ret;
if (!src_fc->ops->dup)
return ERR_PTR(-EOPNOTSUPP);
fc = kmemdup(src_fc, sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
return ERR_PTR(-ENOMEM);
mutex_init(&fc->uapi_mutex);
fc->fs_private = NULL;
fc->s_fs_info = NULL;
fc->source = NULL;
fc->security = NULL;
get_filesystem(fc->fs_type);
get_net(fc->net_ns);
get_user_ns(fc->user_ns);
get_cred(fc->cred);
if (fc->log.log)
refcount_inc(&fc->log.log->usage);
/* Can't call put until we've called ->dup */
ret = fc->ops->dup(fc, src_fc);
if (ret < 0)
goto err_fc;
ret = security_fs_context_dup(fc, src_fc);
if (ret < 0)
goto err_fc;
return fc;
err_fc:
put_fs_context(fc);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(vfs_dup_fs_context);
/**
* logfc - Log a message to a filesystem context
* @log: The filesystem context to log to, or NULL to use printk.
* @prefix: A string to prefix the output with, or NULL.
* @level: 'w' for a warning, 'e' for an error. Anything else is a notice.
* @fmt: The format of the buffer.
*/
void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...)
{
va_list va;
struct va_format vaf = {.fmt = fmt, .va = &va};
va_start(va, fmt);
if (!log) {
switch (level) {
case 'w':
printk(KERN_WARNING "%s%s%pV\n", prefix ? prefix : "",
prefix ? ": " : "", &vaf);
break;
case 'e':
printk(KERN_ERR "%s%s%pV\n", prefix ? prefix : "",
prefix ? ": " : "", &vaf);
break;
default:
printk(KERN_NOTICE "%s%s%pV\n", prefix ? prefix : "",
prefix ? ": " : "", &vaf);
break;
}
} else {
unsigned int logsize = ARRAY_SIZE(log->buffer);
u8 index;
char *q = kasprintf(GFP_KERNEL, "%c %s%s%pV\n", level,
prefix ? prefix : "",
prefix ? ": " : "", &vaf);
index = log->head & (logsize - 1);
BUILD_BUG_ON(sizeof(log->head) != sizeof(u8) ||
sizeof(log->tail) != sizeof(u8));
if ((u8)(log->head - log->tail) == logsize) {
/* The buffer is full, discard the oldest message */
if (log->need_free & (1 << index))
kfree(log->buffer[index]);
log->tail++;
}
log->buffer[index] = q ? q : "OOM: Can't store error string";
if (q)
log->need_free |= 1 << index;
else
log->need_free &= ~(1 << index);
log->head++;
}
va_end(va);
}
EXPORT_SYMBOL(logfc);
/*
* Free a logging structure.
*/
static void put_fc_log(struct fs_context *fc)
{
struct fc_log *log = fc->log.log;
int i;
if (log) {
if (refcount_dec_and_test(&log->usage)) {
fc->log.log = NULL;
for (i = 0; i <= 7; i++)
if (log->need_free & (1 << i))
kfree(log->buffer[i]);
kfree(log);
}
}
}
/**
* put_fs_context - Dispose of a superblock configuration context.
* @fc: The context to dispose of.
*/
void put_fs_context(struct fs_context *fc)
{
struct super_block *sb;
if (fc->root) {
sb = fc->root->d_sb;
dput(fc->root);
fc->root = NULL;
deactivate_super(sb);
}
if (fc->need_free && fc->ops && fc->ops->free)
fc->ops->free(fc);
security_free_mnt_opts(&fc->security);
put_net(fc->net_ns);
put_user_ns(fc->user_ns);
put_cred(fc->cred);
put_fc_log(fc);
put_filesystem(fc->fs_type);
kfree(fc->source);
kfree(fc);
}
EXPORT_SYMBOL(put_fs_context);
/*
* Free the config for a filesystem that doesn't support fs_context.
*/
static void legacy_fs_context_free(struct fs_context *fc)
{
struct legacy_fs_context *ctx = fc->fs_private;
if (ctx) {
if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS)
kfree(ctx->legacy_data);
kfree(ctx);
}
}
/*
* Duplicate a legacy config.
*/
static int legacy_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
{
struct legacy_fs_context *ctx;
struct legacy_fs_context *src_ctx = src_fc->fs_private;
ctx = kmemdup(src_ctx, sizeof(*src_ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS) {
ctx->legacy_data = kmemdup(src_ctx->legacy_data,
src_ctx->data_size, GFP_KERNEL);
if (!ctx->legacy_data) {
kfree(ctx);
return -ENOMEM;
}
}
fc->fs_private = ctx;
return 0;
}
/*
* Add a parameter to a legacy config. We build up a comma-separated list of
* options.
*/
static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct legacy_fs_context *ctx = fc->fs_private;
unsigned int size = ctx->data_size;
size_t len = 0;
int ret;
ret = vfs_parse_fs_param_source(fc, param);
if (ret != -ENOPARAM)
return ret;
if (ctx->param_type == LEGACY_FS_MONOLITHIC_PARAMS)
return invalf(fc, "VFS: Legacy: Can't mix monolithic and individual options");
switch (param->type) {
case fs_value_is_string:
len = 1 + param->size;
fallthrough;
case fs_value_is_flag:
len += strlen(param->key);
break;
default:
return invalf(fc, "VFS: Legacy: Parameter type for '%s' not supported",
param->key);
}
if (size + len + 2 > PAGE_SIZE)
return invalf(fc, "VFS: Legacy: Cumulative options too large");
if (strchr(param->key, ',') ||
(param->type == fs_value_is_string &&
memchr(param->string, ',', param->size)))
return invalf(fc, "VFS: Legacy: Option '%s' contained comma",
param->key);
if (!ctx->legacy_data) {
ctx->legacy_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!ctx->legacy_data)
return -ENOMEM;
}
if (size)
ctx->legacy_data[size++] = ',';
len = strlen(param->key);
memcpy(ctx->legacy_data + size, param->key, len);
size += len;
if (param->type == fs_value_is_string) {
ctx->legacy_data[size++] = '=';
memcpy(ctx->legacy_data + size, param->string, param->size);
size += param->size;
}
ctx->legacy_data[size] = '\0';
ctx->data_size = size;
ctx->param_type = LEGACY_FS_INDIVIDUAL_PARAMS;
return 0;
}
/*
* Add monolithic mount data.
*/
static int legacy_parse_monolithic(struct fs_context *fc, void *data)
{
struct legacy_fs_context *ctx = fc->fs_private;
if (ctx->param_type != LEGACY_FS_UNSET_PARAMS) {
pr_warn("VFS: Can't mix monolithic and individual options\n");
return -EINVAL;
}
ctx->legacy_data = data;
ctx->param_type = LEGACY_FS_MONOLITHIC_PARAMS;
if (!ctx->legacy_data)
return 0;
if (fc->fs_type->fs_flags & FS_BINARY_MOUNTDATA)
return 0;
return security_sb_eat_lsm_opts(ctx->legacy_data, &fc->security);
}
/*
* Get a mountable root with the legacy mount command.
*/
static int legacy_get_tree(struct fs_context *fc)
{
struct legacy_fs_context *ctx = fc->fs_private;
struct super_block *sb;
struct dentry *root;
root = fc->fs_type->mount(fc->fs_type, fc->sb_flags,
fc->source, ctx->legacy_data);
if (IS_ERR(root))
return PTR_ERR(root);
sb = root->d_sb;
BUG_ON(!sb);
fc->root = root;
return 0;
}
/*
* Handle remount.
*/
static int legacy_reconfigure(struct fs_context *fc)
{
struct legacy_fs_context *ctx = fc->fs_private;
struct super_block *sb = fc->root->d_sb;
if (!sb->s_op->remount_fs)
return 0;
return sb->s_op->remount_fs(sb, &fc->sb_flags,
ctx ? ctx->legacy_data : NULL);
}
const struct fs_context_operations legacy_fs_context_ops = {
.free = legacy_fs_context_free,
.dup = legacy_fs_context_dup,
.parse_param = legacy_parse_param,
.parse_monolithic = legacy_parse_monolithic,
.get_tree = legacy_get_tree,
.reconfigure = legacy_reconfigure,
};
/*
* Initialise a legacy context for a filesystem that doesn't support
* fs_context.
*/
static int legacy_init_fs_context(struct fs_context *fc)
{
fc->fs_private = kzalloc(sizeof(struct legacy_fs_context), GFP_KERNEL_ACCOUNT);
if (!fc->fs_private)
return -ENOMEM;
fc->ops = &legacy_fs_context_ops;
return 0;
}
int parse_monolithic_mount_data(struct fs_context *fc, void *data)
{
int (*monolithic_mount_data)(struct fs_context *, void *);
monolithic_mount_data = fc->ops->parse_monolithic;
if (!monolithic_mount_data)
monolithic_mount_data = generic_parse_monolithic;
return monolithic_mount_data(fc, data);
}
/*
* Clean up a context after performing an action on it and put it into a state
* from where it can be used to reconfigure a superblock.
*
* Note that here we do only the parts that can't fail; the rest is in
* finish_clean_context() below and in between those fs_context is marked
* FS_CONTEXT_AWAITING_RECONF. The reason for splitup is that after
* successful mount or remount we need to report success to userland.
* Trying to do full reinit (for the sake of possible subsequent remount)
* and failing to allocate memory would've put us into a nasty situation.
* So here we only discard the old state and reinitialization is left
* until we actually try to reconfigure.
*/
void vfs_clean_context(struct fs_context *fc)
{
if (fc->need_free && fc->ops && fc->ops->free)
fc->ops->free(fc);
fc->need_free = false;
fc->fs_private = NULL;
fc->s_fs_info = NULL;
fc->sb_flags = 0;
security_free_mnt_opts(&fc->security);
kfree(fc->source);
fc->source = NULL;
fc->exclusive = false;
fc->purpose = FS_CONTEXT_FOR_RECONFIGURE;
fc->phase = FS_CONTEXT_AWAITING_RECONF;
}
int finish_clean_context(struct fs_context *fc)
{
int error;
if (fc->phase != FS_CONTEXT_AWAITING_RECONF)
return 0;
if (fc->fs_type->init_fs_context)
error = fc->fs_type->init_fs_context(fc);
else
error = legacy_init_fs_context(fc);
if (unlikely(error)) {
fc->phase = FS_CONTEXT_FAILED;
return error;
}
fc->need_free = true;
fc->phase = FS_CONTEXT_RECONF_PARAMS;
return 0;
}
| linux-master | fs/fs_context.c |
/*
* An async IO implementation for Linux
* Written by Benjamin LaHaise <[email protected]>
*
* Implements an efficient asynchronous io interface.
*
* Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
* Copyright 2018 Christoph Hellwig.
*
* See ../COPYING for licensing terms.
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/aio_abi.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/backing-dev.h>
#include <linux/refcount.h>
#include <linux/uio.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/aio.h>
#include <linux/highmem.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/eventfd.h>
#include <linux/blkdev.h>
#include <linux/compat.h>
#include <linux/migrate.h>
#include <linux/ramfs.h>
#include <linux/percpu-refcount.h>
#include <linux/mount.h>
#include <linux/pseudo_fs.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include "internal.h"
#define KIOCB_KEY 0
#define AIO_RING_MAGIC 0xa10a10a1
#define AIO_RING_COMPAT_FEATURES 1
#define AIO_RING_INCOMPAT_FEATURES 0
struct aio_ring {
unsigned id; /* kernel internal index number */
unsigned nr; /* number of io_events */
unsigned head; /* Written to by userland or under ring_lock
* mutex by aio_read_events_ring(). */
unsigned tail;
unsigned magic;
unsigned compat_features;
unsigned incompat_features;
unsigned header_length; /* size of aio_ring */
struct io_event io_events[];
}; /* 128 bytes + ring size */
/*
* Plugging is meant to work with larger batches of IOs. If we don't
* have more than the below, then don't bother setting up a plug.
*/
#define AIO_PLUG_THRESHOLD 2
#define AIO_RING_PAGES 8
struct kioctx_table {
struct rcu_head rcu;
unsigned nr;
struct kioctx __rcu *table[];
};
struct kioctx_cpu {
unsigned reqs_available;
};
struct ctx_rq_wait {
struct completion comp;
atomic_t count;
};
struct kioctx {
struct percpu_ref users;
atomic_t dead;
struct percpu_ref reqs;
unsigned long user_id;
struct __percpu kioctx_cpu *cpu;
/*
* For percpu reqs_available, number of slots we move to/from global
* counter at a time:
*/
unsigned req_batch;
/*
* This is what userspace passed to io_setup(), it's not used for
* anything but counting against the global max_reqs quota.
*
* The real limit is nr_events - 1, which will be larger (see
* aio_setup_ring())
*/
unsigned max_reqs;
/* Size of ringbuffer, in units of struct io_event */
unsigned nr_events;
unsigned long mmap_base;
unsigned long mmap_size;
struct page **ring_pages;
long nr_pages;
struct rcu_work free_rwork; /* see free_ioctx() */
/*
* signals when all in-flight requests are done
*/
struct ctx_rq_wait *rq_wait;
struct {
/*
* This counts the number of available slots in the ringbuffer,
* so we avoid overflowing it: it's decremented (if positive)
* when allocating a kiocb and incremented when the resulting
* io_event is pulled off the ringbuffer.
*
* We batch accesses to it with a percpu version.
*/
atomic_t reqs_available;
} ____cacheline_aligned_in_smp;
struct {
spinlock_t ctx_lock;
struct list_head active_reqs; /* used for cancellation */
} ____cacheline_aligned_in_smp;
struct {
struct mutex ring_lock;
wait_queue_head_t wait;
} ____cacheline_aligned_in_smp;
struct {
unsigned tail;
unsigned completed_events;
spinlock_t completion_lock;
} ____cacheline_aligned_in_smp;
struct page *internal_pages[AIO_RING_PAGES];
struct file *aio_ring_file;
unsigned id;
};
/*
* First field must be the file pointer in all the
* iocb unions! See also 'struct kiocb' in <linux/fs.h>
*/
struct fsync_iocb {
struct file *file;
struct work_struct work;
bool datasync;
struct cred *creds;
};
struct poll_iocb {
struct file *file;
struct wait_queue_head *head;
__poll_t events;
bool cancelled;
bool work_scheduled;
bool work_need_resched;
struct wait_queue_entry wait;
struct work_struct work;
};
/*
* NOTE! Each of the iocb union members has the file pointer
* as the first entry in their struct definition. So you can
* access the file pointer through any of the sub-structs,
* or directly as just 'ki_filp' in this struct.
*/
struct aio_kiocb {
union {
struct file *ki_filp;
struct kiocb rw;
struct fsync_iocb fsync;
struct poll_iocb poll;
};
struct kioctx *ki_ctx;
kiocb_cancel_fn *ki_cancel;
struct io_event ki_res;
struct list_head ki_list; /* the aio core uses this
* for cancellation */
refcount_t ki_refcnt;
/*
* If the aio_resfd field of the userspace iocb is not zero,
* this is the underlying eventfd context to deliver events to.
*/
struct eventfd_ctx *ki_eventfd;
};
/*------ sysctl variables----*/
static DEFINE_SPINLOCK(aio_nr_lock);
static unsigned long aio_nr; /* current system wide number of aio requests */
static unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
/*----end sysctl variables---*/
#ifdef CONFIG_SYSCTL
static struct ctl_table aio_sysctls[] = {
{
.procname = "aio-nr",
.data = &aio_nr,
.maxlen = sizeof(aio_nr),
.mode = 0444,
.proc_handler = proc_doulongvec_minmax,
},
{
.procname = "aio-max-nr",
.data = &aio_max_nr,
.maxlen = sizeof(aio_max_nr),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{}
};
static void __init aio_sysctl_init(void)
{
register_sysctl_init("fs", aio_sysctls);
}
#else
#define aio_sysctl_init() do { } while (0)
#endif
static struct kmem_cache *kiocb_cachep;
static struct kmem_cache *kioctx_cachep;
static struct vfsmount *aio_mnt;
static const struct file_operations aio_ring_fops;
static const struct address_space_operations aio_ctx_aops;
static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
{
struct file *file;
struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
if (IS_ERR(inode))
return ERR_CAST(inode);
inode->i_mapping->a_ops = &aio_ctx_aops;
inode->i_mapping->private_data = ctx;
inode->i_size = PAGE_SIZE * nr_pages;
file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
O_RDWR, &aio_ring_fops);
if (IS_ERR(file))
iput(inode);
return file;
}
static int aio_init_fs_context(struct fs_context *fc)
{
if (!init_pseudo(fc, AIO_RING_MAGIC))
return -ENOMEM;
fc->s_iflags |= SB_I_NOEXEC;
return 0;
}
/* aio_setup
* Creates the slab caches used by the aio routines, panic on
* failure as this is done early during the boot sequence.
*/
static int __init aio_setup(void)
{
static struct file_system_type aio_fs = {
.name = "aio",
.init_fs_context = aio_init_fs_context,
.kill_sb = kill_anon_super,
};
aio_mnt = kern_mount(&aio_fs);
if (IS_ERR(aio_mnt))
panic("Failed to create aio fs mount.");
kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
aio_sysctl_init();
return 0;
}
__initcall(aio_setup);
static void put_aio_ring_file(struct kioctx *ctx)
{
struct file *aio_ring_file = ctx->aio_ring_file;
struct address_space *i_mapping;
if (aio_ring_file) {
truncate_setsize(file_inode(aio_ring_file), 0);
/* Prevent further access to the kioctx from migratepages */
i_mapping = aio_ring_file->f_mapping;
spin_lock(&i_mapping->private_lock);
i_mapping->private_data = NULL;
ctx->aio_ring_file = NULL;
spin_unlock(&i_mapping->private_lock);
fput(aio_ring_file);
}
}
static void aio_free_ring(struct kioctx *ctx)
{
int i;
/* Disconnect the kiotx from the ring file. This prevents future
* accesses to the kioctx from page migration.
*/
put_aio_ring_file(ctx);
for (i = 0; i < ctx->nr_pages; i++) {
struct page *page;
pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
page_count(ctx->ring_pages[i]));
page = ctx->ring_pages[i];
if (!page)
continue;
ctx->ring_pages[i] = NULL;
put_page(page);
}
if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
kfree(ctx->ring_pages);
ctx->ring_pages = NULL;
}
}
static int aio_ring_mremap(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct mm_struct *mm = vma->vm_mm;
struct kioctx_table *table;
int i, res = -EINVAL;
spin_lock(&mm->ioctx_lock);
rcu_read_lock();
table = rcu_dereference(mm->ioctx_table);
if (!table)
goto out_unlock;
for (i = 0; i < table->nr; i++) {
struct kioctx *ctx;
ctx = rcu_dereference(table->table[i]);
if (ctx && ctx->aio_ring_file == file) {
if (!atomic_read(&ctx->dead)) {
ctx->user_id = ctx->mmap_base = vma->vm_start;
res = 0;
}
break;
}
}
out_unlock:
rcu_read_unlock();
spin_unlock(&mm->ioctx_lock);
return res;
}
static const struct vm_operations_struct aio_ring_vm_ops = {
.mremap = aio_ring_mremap,
#if IS_ENABLED(CONFIG_MMU)
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = filemap_page_mkwrite,
#endif
};
static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
{
vm_flags_set(vma, VM_DONTEXPAND);
vma->vm_ops = &aio_ring_vm_ops;
return 0;
}
static const struct file_operations aio_ring_fops = {
.mmap = aio_ring_mmap,
};
#if IS_ENABLED(CONFIG_MIGRATION)
static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
struct folio *src, enum migrate_mode mode)
{
struct kioctx *ctx;
unsigned long flags;
pgoff_t idx;
int rc;
/*
* We cannot support the _NO_COPY case here, because copy needs to
* happen under the ctx->completion_lock. That does not work with the
* migration workflow of MIGRATE_SYNC_NO_COPY.
*/
if (mode == MIGRATE_SYNC_NO_COPY)
return -EINVAL;
rc = 0;
/* mapping->private_lock here protects against the kioctx teardown. */
spin_lock(&mapping->private_lock);
ctx = mapping->private_data;
if (!ctx) {
rc = -EINVAL;
goto out;
}
/* The ring_lock mutex. The prevents aio_read_events() from writing
* to the ring's head, and prevents page migration from mucking in
* a partially initialized kiotx.
*/
if (!mutex_trylock(&ctx->ring_lock)) {
rc = -EAGAIN;
goto out;
}
idx = src->index;
if (idx < (pgoff_t)ctx->nr_pages) {
/* Make sure the old folio hasn't already been changed */
if (ctx->ring_pages[idx] != &src->page)
rc = -EAGAIN;
} else
rc = -EINVAL;
if (rc != 0)
goto out_unlock;
/* Writeback must be complete */
BUG_ON(folio_test_writeback(src));
folio_get(dst);
rc = folio_migrate_mapping(mapping, dst, src, 1);
if (rc != MIGRATEPAGE_SUCCESS) {
folio_put(dst);
goto out_unlock;
}
/* Take completion_lock to prevent other writes to the ring buffer
* while the old folio is copied to the new. This prevents new
* events from being lost.
*/
spin_lock_irqsave(&ctx->completion_lock, flags);
folio_migrate_copy(dst, src);
BUG_ON(ctx->ring_pages[idx] != &src->page);
ctx->ring_pages[idx] = &dst->page;
spin_unlock_irqrestore(&ctx->completion_lock, flags);
/* The old folio is no longer accessible. */
folio_put(src);
out_unlock:
mutex_unlock(&ctx->ring_lock);
out:
spin_unlock(&mapping->private_lock);
return rc;
}
#else
#define aio_migrate_folio NULL
#endif
static const struct address_space_operations aio_ctx_aops = {
.dirty_folio = noop_dirty_folio,
.migrate_folio = aio_migrate_folio,
};
static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
{
struct aio_ring *ring;
struct mm_struct *mm = current->mm;
unsigned long size, unused;
int nr_pages;
int i;
struct file *file;
/* Compensate for the ring buffer's head/tail overlap entry */
nr_events += 2; /* 1 is required, 2 for good luck */
size = sizeof(struct aio_ring);
size += sizeof(struct io_event) * nr_events;
nr_pages = PFN_UP(size);
if (nr_pages < 0)
return -EINVAL;
file = aio_private_file(ctx, nr_pages);
if (IS_ERR(file)) {
ctx->aio_ring_file = NULL;
return -ENOMEM;
}
ctx->aio_ring_file = file;
nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
/ sizeof(struct io_event);
ctx->ring_pages = ctx->internal_pages;
if (nr_pages > AIO_RING_PAGES) {
ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
GFP_KERNEL);
if (!ctx->ring_pages) {
put_aio_ring_file(ctx);
return -ENOMEM;
}
}
for (i = 0; i < nr_pages; i++) {
struct page *page;
page = find_or_create_page(file->f_mapping,
i, GFP_USER | __GFP_ZERO);
if (!page)
break;
pr_debug("pid(%d) page[%d]->count=%d\n",
current->pid, i, page_count(page));
SetPageUptodate(page);
unlock_page(page);
ctx->ring_pages[i] = page;
}
ctx->nr_pages = i;
if (unlikely(i != nr_pages)) {
aio_free_ring(ctx);
return -ENOMEM;
}
ctx->mmap_size = nr_pages * PAGE_SIZE;
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
if (mmap_write_lock_killable(mm)) {
ctx->mmap_size = 0;
aio_free_ring(ctx);
return -EINTR;
}
ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
PROT_READ | PROT_WRITE,
MAP_SHARED, 0, 0, &unused, NULL);
mmap_write_unlock(mm);
if (IS_ERR((void *)ctx->mmap_base)) {
ctx->mmap_size = 0;
aio_free_ring(ctx);
return -ENOMEM;
}
pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
ctx->user_id = ctx->mmap_base;
ctx->nr_events = nr_events; /* trusted copy */
ring = page_address(ctx->ring_pages[0]);
ring->nr = nr_events; /* user copy */
ring->id = ~0U;
ring->head = ring->tail = 0;
ring->magic = AIO_RING_MAGIC;
ring->compat_features = AIO_RING_COMPAT_FEATURES;
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
ring->header_length = sizeof(struct aio_ring);
flush_dcache_page(ctx->ring_pages[0]);
return 0;
}
#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
{
struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
struct kioctx *ctx = req->ki_ctx;
unsigned long flags;
if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
return;
spin_lock_irqsave(&ctx->ctx_lock, flags);
list_add_tail(&req->ki_list, &ctx->active_reqs);
req->ki_cancel = cancel;
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
}
EXPORT_SYMBOL(kiocb_set_cancel_fn);
/*
* free_ioctx() should be RCU delayed to synchronize against the RCU
* protected lookup_ioctx() and also needs process context to call
* aio_free_ring(). Use rcu_work.
*/
static void free_ioctx(struct work_struct *work)
{
struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
free_rwork);
pr_debug("freeing %p\n", ctx);
aio_free_ring(ctx);
free_percpu(ctx->cpu);
percpu_ref_exit(&ctx->reqs);
percpu_ref_exit(&ctx->users);
kmem_cache_free(kioctx_cachep, ctx);
}
static void free_ioctx_reqs(struct percpu_ref *ref)
{
struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
/* At this point we know that there are no any in-flight requests */
if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
complete(&ctx->rq_wait->comp);
/* Synchronize against RCU protected table->table[] dereferences */
INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
queue_rcu_work(system_wq, &ctx->free_rwork);
}
/*
* When this function runs, the kioctx has been removed from the "hash table"
* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
* now it's safe to cancel any that need to be.
*/
static void free_ioctx_users(struct percpu_ref *ref)
{
struct kioctx *ctx = container_of(ref, struct kioctx, users);
struct aio_kiocb *req;
spin_lock_irq(&ctx->ctx_lock);
while (!list_empty(&ctx->active_reqs)) {
req = list_first_entry(&ctx->active_reqs,
struct aio_kiocb, ki_list);
req->ki_cancel(&req->rw);
list_del_init(&req->ki_list);
}
spin_unlock_irq(&ctx->ctx_lock);
percpu_ref_kill(&ctx->reqs);
percpu_ref_put(&ctx->reqs);
}
static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
{
unsigned i, new_nr;
struct kioctx_table *table, *old;
struct aio_ring *ring;
spin_lock(&mm->ioctx_lock);
table = rcu_dereference_raw(mm->ioctx_table);
while (1) {
if (table)
for (i = 0; i < table->nr; i++)
if (!rcu_access_pointer(table->table[i])) {
ctx->id = i;
rcu_assign_pointer(table->table[i], ctx);
spin_unlock(&mm->ioctx_lock);
/* While kioctx setup is in progress,
* we are protected from page migration
* changes ring_pages by ->ring_lock.
*/
ring = page_address(ctx->ring_pages[0]);
ring->id = ctx->id;
return 0;
}
new_nr = (table ? table->nr : 1) * 4;
spin_unlock(&mm->ioctx_lock);
table = kzalloc(struct_size(table, table, new_nr), GFP_KERNEL);
if (!table)
return -ENOMEM;
table->nr = new_nr;
spin_lock(&mm->ioctx_lock);
old = rcu_dereference_raw(mm->ioctx_table);
if (!old) {
rcu_assign_pointer(mm->ioctx_table, table);
} else if (table->nr > old->nr) {
memcpy(table->table, old->table,
old->nr * sizeof(struct kioctx *));
rcu_assign_pointer(mm->ioctx_table, table);
kfree_rcu(old, rcu);
} else {
kfree(table);
table = old;
}
}
}
static void aio_nr_sub(unsigned nr)
{
spin_lock(&aio_nr_lock);
if (WARN_ON(aio_nr - nr > aio_nr))
aio_nr = 0;
else
aio_nr -= nr;
spin_unlock(&aio_nr_lock);
}
/* ioctx_alloc
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
*/
static struct kioctx *ioctx_alloc(unsigned nr_events)
{
struct mm_struct *mm = current->mm;
struct kioctx *ctx;
int err = -ENOMEM;
/*
* Store the original nr_events -- what userspace passed to io_setup(),
* for counting against the global limit -- before it changes.
*/
unsigned int max_reqs = nr_events;
/*
* We keep track of the number of available ringbuffer slots, to prevent
* overflow (reqs_available), and we also use percpu counters for this.
*
* So since up to half the slots might be on other cpu's percpu counters
* and unavailable, double nr_events so userspace sees what they
* expected: additionally, we move req_batch slots to/from percpu
* counters at a time, so make sure that isn't 0:
*/
nr_events = max(nr_events, num_possible_cpus() * 4);
nr_events *= 2;
/* Prevent overflows */
if (nr_events > (0x10000000U / sizeof(struct io_event))) {
pr_debug("ENOMEM: nr_events too high\n");
return ERR_PTR(-EINVAL);
}
if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
return ERR_PTR(-EAGAIN);
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->max_reqs = max_reqs;
spin_lock_init(&ctx->ctx_lock);
spin_lock_init(&ctx->completion_lock);
mutex_init(&ctx->ring_lock);
/* Protect against page migration throughout kiotx setup by keeping
* the ring_lock mutex held until setup is complete. */
mutex_lock(&ctx->ring_lock);
init_waitqueue_head(&ctx->wait);
INIT_LIST_HEAD(&ctx->active_reqs);
if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
goto err;
if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
goto err;
ctx->cpu = alloc_percpu(struct kioctx_cpu);
if (!ctx->cpu)
goto err;
err = aio_setup_ring(ctx, nr_events);
if (err < 0)
goto err;
atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
if (ctx->req_batch < 1)
ctx->req_batch = 1;
/* limit the number of system wide aios */
spin_lock(&aio_nr_lock);
if (aio_nr + ctx->max_reqs > aio_max_nr ||
aio_nr + ctx->max_reqs < aio_nr) {
spin_unlock(&aio_nr_lock);
err = -EAGAIN;
goto err_ctx;
}
aio_nr += ctx->max_reqs;
spin_unlock(&aio_nr_lock);
percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
err = ioctx_add_table(ctx, mm);
if (err)
goto err_cleanup;
/* Release the ring_lock mutex now that all setup is complete. */
mutex_unlock(&ctx->ring_lock);
pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
ctx, ctx->user_id, mm, ctx->nr_events);
return ctx;
err_cleanup:
aio_nr_sub(ctx->max_reqs);
err_ctx:
atomic_set(&ctx->dead, 1);
if (ctx->mmap_size)
vm_munmap(ctx->mmap_base, ctx->mmap_size);
aio_free_ring(ctx);
err:
mutex_unlock(&ctx->ring_lock);
free_percpu(ctx->cpu);
percpu_ref_exit(&ctx->reqs);
percpu_ref_exit(&ctx->users);
kmem_cache_free(kioctx_cachep, ctx);
pr_debug("error allocating ioctx %d\n", err);
return ERR_PTR(err);
}
/* kill_ioctx
* Cancels all outstanding aio requests on an aio context. Used
* when the processes owning a context have all exited to encourage
* the rapid destruction of the kioctx.
*/
static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
struct ctx_rq_wait *wait)
{
struct kioctx_table *table;
spin_lock(&mm->ioctx_lock);
if (atomic_xchg(&ctx->dead, 1)) {
spin_unlock(&mm->ioctx_lock);
return -EINVAL;
}
table = rcu_dereference_raw(mm->ioctx_table);
WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
RCU_INIT_POINTER(table->table[ctx->id], NULL);
spin_unlock(&mm->ioctx_lock);
/* free_ioctx_reqs() will do the necessary RCU synchronization */
wake_up_all(&ctx->wait);
/*
* It'd be more correct to do this in free_ioctx(), after all
* the outstanding kiocbs have finished - but by then io_destroy
* has already returned, so io_setup() could potentially return
* -EAGAIN with no ioctxs actually in use (as far as userspace
* could tell).
*/
aio_nr_sub(ctx->max_reqs);
if (ctx->mmap_size)
vm_munmap(ctx->mmap_base, ctx->mmap_size);
ctx->rq_wait = wait;
percpu_ref_kill(&ctx->users);
return 0;
}
/*
* exit_aio: called when the last user of mm goes away. At this point, there is
* no way for any new requests to be submited or any of the io_* syscalls to be
* called on the context.
*
* There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
* them.
*/
void exit_aio(struct mm_struct *mm)
{
struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
struct ctx_rq_wait wait;
int i, skipped;
if (!table)
return;
atomic_set(&wait.count, table->nr);
init_completion(&wait.comp);
skipped = 0;
for (i = 0; i < table->nr; ++i) {
struct kioctx *ctx =
rcu_dereference_protected(table->table[i], true);
if (!ctx) {
skipped++;
continue;
}
/*
* We don't need to bother with munmap() here - exit_mmap(mm)
* is coming and it'll unmap everything. And we simply can't,
* this is not necessarily our ->mm.
* Since kill_ioctx() uses non-zero ->mmap_size as indicator
* that it needs to unmap the area, just set it to 0.
*/
ctx->mmap_size = 0;
kill_ioctx(mm, ctx, &wait);
}
if (!atomic_sub_and_test(skipped, &wait.count)) {
/* Wait until all IO for the context are done. */
wait_for_completion(&wait.comp);
}
RCU_INIT_POINTER(mm->ioctx_table, NULL);
kfree(table);
}
static void put_reqs_available(struct kioctx *ctx, unsigned nr)
{
struct kioctx_cpu *kcpu;
unsigned long flags;
local_irq_save(flags);
kcpu = this_cpu_ptr(ctx->cpu);
kcpu->reqs_available += nr;
while (kcpu->reqs_available >= ctx->req_batch * 2) {
kcpu->reqs_available -= ctx->req_batch;
atomic_add(ctx->req_batch, &ctx->reqs_available);
}
local_irq_restore(flags);
}
static bool __get_reqs_available(struct kioctx *ctx)
{
struct kioctx_cpu *kcpu;
bool ret = false;
unsigned long flags;
local_irq_save(flags);
kcpu = this_cpu_ptr(ctx->cpu);
if (!kcpu->reqs_available) {
int avail = atomic_read(&ctx->reqs_available);
do {
if (avail < ctx->req_batch)
goto out;
} while (!atomic_try_cmpxchg(&ctx->reqs_available,
&avail, avail - ctx->req_batch));
kcpu->reqs_available += ctx->req_batch;
}
ret = true;
kcpu->reqs_available--;
out:
local_irq_restore(flags);
return ret;
}
/* refill_reqs_available
* Updates the reqs_available reference counts used for tracking the
* number of free slots in the completion ring. This can be called
* from aio_complete() (to optimistically update reqs_available) or
* from aio_get_req() (the we're out of events case). It must be
* called holding ctx->completion_lock.
*/
static void refill_reqs_available(struct kioctx *ctx, unsigned head,
unsigned tail)
{
unsigned events_in_ring, completed;
/* Clamp head since userland can write to it. */
head %= ctx->nr_events;
if (head <= tail)
events_in_ring = tail - head;
else
events_in_ring = ctx->nr_events - (head - tail);
completed = ctx->completed_events;
if (events_in_ring < completed)
completed -= events_in_ring;
else
completed = 0;
if (!completed)
return;
ctx->completed_events -= completed;
put_reqs_available(ctx, completed);
}
/* user_refill_reqs_available
* Called to refill reqs_available when aio_get_req() encounters an
* out of space in the completion ring.
*/
static void user_refill_reqs_available(struct kioctx *ctx)
{
spin_lock_irq(&ctx->completion_lock);
if (ctx->completed_events) {
struct aio_ring *ring;
unsigned head;
/* Access of ring->head may race with aio_read_events_ring()
* here, but that's okay since whether we read the old version
* or the new version, and either will be valid. The important
* part is that head cannot pass tail since we prevent
* aio_complete() from updating tail by holding
* ctx->completion_lock. Even if head is invalid, the check
* against ctx->completed_events below will make sure we do the
* safe/right thing.
*/
ring = page_address(ctx->ring_pages[0]);
head = ring->head;
refill_reqs_available(ctx, head, ctx->tail);
}
spin_unlock_irq(&ctx->completion_lock);
}
static bool get_reqs_available(struct kioctx *ctx)
{
if (__get_reqs_available(ctx))
return true;
user_refill_reqs_available(ctx);
return __get_reqs_available(ctx);
}
/* aio_get_req
* Allocate a slot for an aio request.
* Returns NULL if no requests are free.
*
* The refcount is initialized to 2 - one for the async op completion,
* one for the synchronous code that does this.
*/
static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
{
struct aio_kiocb *req;
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
if (unlikely(!req))
return NULL;
if (unlikely(!get_reqs_available(ctx))) {
kmem_cache_free(kiocb_cachep, req);
return NULL;
}
percpu_ref_get(&ctx->reqs);
req->ki_ctx = ctx;
INIT_LIST_HEAD(&req->ki_list);
refcount_set(&req->ki_refcnt, 2);
req->ki_eventfd = NULL;
return req;
}
static struct kioctx *lookup_ioctx(unsigned long ctx_id)
{
struct aio_ring __user *ring = (void __user *)ctx_id;
struct mm_struct *mm = current->mm;
struct kioctx *ctx, *ret = NULL;
struct kioctx_table *table;
unsigned id;
if (get_user(id, &ring->id))
return NULL;
rcu_read_lock();
table = rcu_dereference(mm->ioctx_table);
if (!table || id >= table->nr)
goto out;
id = array_index_nospec(id, table->nr);
ctx = rcu_dereference(table->table[id]);
if (ctx && ctx->user_id == ctx_id) {
if (percpu_ref_tryget_live(&ctx->users))
ret = ctx;
}
out:
rcu_read_unlock();
return ret;
}
static inline void iocb_destroy(struct aio_kiocb *iocb)
{
if (iocb->ki_eventfd)
eventfd_ctx_put(iocb->ki_eventfd);
if (iocb->ki_filp)
fput(iocb->ki_filp);
percpu_ref_put(&iocb->ki_ctx->reqs);
kmem_cache_free(kiocb_cachep, iocb);
}
/* aio_complete
* Called when the io request on the given iocb is complete.
*/
static void aio_complete(struct aio_kiocb *iocb)
{
struct kioctx *ctx = iocb->ki_ctx;
struct aio_ring *ring;
struct io_event *ev_page, *event;
unsigned tail, pos, head;
unsigned long flags;
/*
* Add a completion event to the ring buffer. Must be done holding
* ctx->completion_lock to prevent other code from messing with the tail
* pointer since we might be called from irq context.
*/
spin_lock_irqsave(&ctx->completion_lock, flags);
tail = ctx->tail;
pos = tail + AIO_EVENTS_OFFSET;
if (++tail >= ctx->nr_events)
tail = 0;
ev_page = page_address(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
event = ev_page + pos % AIO_EVENTS_PER_PAGE;
*event = iocb->ki_res;
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,
(void __user *)(unsigned long)iocb->ki_res.obj,
iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2);
/* after flagging the request as done, we
* must never even look at it again
*/
smp_wmb(); /* make event visible before updating tail */
ctx->tail = tail;
ring = page_address(ctx->ring_pages[0]);
head = ring->head;
ring->tail = tail;
flush_dcache_page(ctx->ring_pages[0]);
ctx->completed_events++;
if (ctx->completed_events > 1)
refill_reqs_available(ctx, head, tail);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
pr_debug("added to ring %p at [%u]\n", iocb, tail);
/*
* Check if the user asked us to deliver the result through an
* eventfd. The eventfd_signal() function is safe to be called
* from IRQ context.
*/
if (iocb->ki_eventfd)
eventfd_signal(iocb->ki_eventfd, 1);
/*
* We have to order our ring_info tail store above and test
* of the wait list below outside the wait lock. This is
* like in wake_up_bit() where clearing a bit has to be
* ordered with the unlocked test.
*/
smp_mb();
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
}
static inline void iocb_put(struct aio_kiocb *iocb)
{
if (refcount_dec_and_test(&iocb->ki_refcnt)) {
aio_complete(iocb);
iocb_destroy(iocb);
}
}
/* aio_read_events_ring
* Pull an event off of the ioctx's event ring. Returns the number of
* events fetched
*/
static long aio_read_events_ring(struct kioctx *ctx,
struct io_event __user *event, long nr)
{
struct aio_ring *ring;
unsigned head, tail, pos;
long ret = 0;
int copy_ret;
/*
* The mutex can block and wake us up and that will cause
* wait_event_interruptible_hrtimeout() to schedule without sleeping
* and repeat. This should be rare enough that it doesn't cause
* peformance issues. See the comment in read_events() for more detail.
*/
sched_annotate_sleep();
mutex_lock(&ctx->ring_lock);
/* Access to ->ring_pages here is protected by ctx->ring_lock. */
ring = page_address(ctx->ring_pages[0]);
head = ring->head;
tail = ring->tail;
/*
* Ensure that once we've read the current tail pointer, that
* we also see the events that were stored up to the tail.
*/
smp_rmb();
pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
if (head == tail)
goto out;
head %= ctx->nr_events;
tail %= ctx->nr_events;
while (ret < nr) {
long avail;
struct io_event *ev;
struct page *page;
avail = (head <= tail ? tail : ctx->nr_events) - head;
if (head == tail)
break;
pos = head + AIO_EVENTS_OFFSET;
page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
pos %= AIO_EVENTS_PER_PAGE;
avail = min(avail, nr - ret);
avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
ev = page_address(page);
copy_ret = copy_to_user(event + ret, ev + pos,
sizeof(*ev) * avail);
if (unlikely(copy_ret)) {
ret = -EFAULT;
goto out;
}
ret += avail;
head += avail;
head %= ctx->nr_events;
}
ring = page_address(ctx->ring_pages[0]);
ring->head = head;
flush_dcache_page(ctx->ring_pages[0]);
pr_debug("%li h%u t%u\n", ret, head, tail);
out:
mutex_unlock(&ctx->ring_lock);
return ret;
}
static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
struct io_event __user *event, long *i)
{
long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
if (ret > 0)
*i += ret;
if (unlikely(atomic_read(&ctx->dead)))
ret = -EINVAL;
if (!*i)
*i = ret;
return ret < 0 || *i >= min_nr;
}
static long read_events(struct kioctx *ctx, long min_nr, long nr,
struct io_event __user *event,
ktime_t until)
{
long ret = 0;
/*
* Note that aio_read_events() is being called as the conditional - i.e.
* we're calling it after prepare_to_wait() has set task state to
* TASK_INTERRUPTIBLE.
*
* But aio_read_events() can block, and if it blocks it's going to flip
* the task state back to TASK_RUNNING.
*
* This should be ok, provided it doesn't flip the state back to
* TASK_RUNNING and return 0 too much - that causes us to spin. That
* will only happen if the mutex_lock() call blocks, and we then find
* the ringbuffer empty. So in practice we should be ok, but it's
* something to be aware of when touching this code.
*/
if (until == 0)
aio_read_events(ctx, min_nr, nr, event, &ret);
else
wait_event_interruptible_hrtimeout(ctx->wait,
aio_read_events(ctx, min_nr, nr, event, &ret),
until);
return ret;
}
/* sys_io_setup:
* Create an aio_context capable of receiving at least nr_events.
* ctxp must not point to an aio_context that already exists, and
* must be initialized to 0 prior to the call. On successful
* creation of the aio_context, *ctxp is filled in with the resulting
* handle. May fail with -EINVAL if *ctxp is not initialized,
* if the specified nr_events exceeds internal limits. May fail
* with -EAGAIN if the specified nr_events exceeds the user's limit
* of available events. May fail with -ENOMEM if insufficient kernel
* resources are available. May fail with -EFAULT if an invalid
* pointer is passed for ctxp. Will fail with -ENOSYS if not
* implemented.
*/
SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
{
struct kioctx *ioctx = NULL;
unsigned long ctx;
long ret;
ret = get_user(ctx, ctxp);
if (unlikely(ret))
goto out;
ret = -EINVAL;
if (unlikely(ctx || nr_events == 0)) {
pr_debug("EINVAL: ctx %lu nr_events %u\n",
ctx, nr_events);
goto out;
}
ioctx = ioctx_alloc(nr_events);
ret = PTR_ERR(ioctx);
if (!IS_ERR(ioctx)) {
ret = put_user(ioctx->user_id, ctxp);
if (ret)
kill_ioctx(current->mm, ioctx, NULL);
percpu_ref_put(&ioctx->users);
}
out:
return ret;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
{
struct kioctx *ioctx = NULL;
unsigned long ctx;
long ret;
ret = get_user(ctx, ctx32p);
if (unlikely(ret))
goto out;
ret = -EINVAL;
if (unlikely(ctx || nr_events == 0)) {
pr_debug("EINVAL: ctx %lu nr_events %u\n",
ctx, nr_events);
goto out;
}
ioctx = ioctx_alloc(nr_events);
ret = PTR_ERR(ioctx);
if (!IS_ERR(ioctx)) {
/* truncating is ok because it's a user address */
ret = put_user((u32)ioctx->user_id, ctx32p);
if (ret)
kill_ioctx(current->mm, ioctx, NULL);
percpu_ref_put(&ioctx->users);
}
out:
return ret;
}
#endif
/* sys_io_destroy:
* Destroy the aio_context specified. May cancel any outstanding
* AIOs and block on completion. Will fail with -ENOSYS if not
* implemented. May fail with -EINVAL if the context pointed to
* is invalid.
*/
SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
{
struct kioctx *ioctx = lookup_ioctx(ctx);
if (likely(NULL != ioctx)) {
struct ctx_rq_wait wait;
int ret;
init_completion(&wait.comp);
atomic_set(&wait.count, 1);
/* Pass requests_done to kill_ioctx() where it can be set
* in a thread-safe way. If we try to set it here then we have
* a race condition if two io_destroy() called simultaneously.
*/
ret = kill_ioctx(current->mm, ioctx, &wait);
percpu_ref_put(&ioctx->users);
/* Wait until all IO for the context are done. Otherwise kernel
* keep using user-space buffers even if user thinks the context
* is destroyed.
*/
if (!ret)
wait_for_completion(&wait.comp);
return ret;
}
pr_debug("EINVAL: invalid context id\n");
return -EINVAL;
}
static void aio_remove_iocb(struct aio_kiocb *iocb)
{
struct kioctx *ctx = iocb->ki_ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->ctx_lock, flags);
list_del(&iocb->ki_list);
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
}
static void aio_complete_rw(struct kiocb *kiocb, long res)
{
struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);
if (!list_empty_careful(&iocb->ki_list))
aio_remove_iocb(iocb);
if (kiocb->ki_flags & IOCB_WRITE) {
struct inode *inode = file_inode(kiocb->ki_filp);
if (S_ISREG(inode->i_mode))
kiocb_end_write(kiocb);
}
iocb->ki_res.res = res;
iocb->ki_res.res2 = 0;
iocb_put(iocb);
}
static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
{
int ret;
req->ki_complete = aio_complete_rw;
req->private = NULL;
req->ki_pos = iocb->aio_offset;
req->ki_flags = req->ki_filp->f_iocb_flags;
if (iocb->aio_flags & IOCB_FLAG_RESFD)
req->ki_flags |= IOCB_EVENTFD;
if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
/*
* If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
* aio_reqprio is interpreted as an I/O scheduling
* class and priority.
*/
ret = ioprio_check_cap(iocb->aio_reqprio);
if (ret) {
pr_debug("aio ioprio check cap error: %d\n", ret);
return ret;
}
req->ki_ioprio = iocb->aio_reqprio;
} else
req->ki_ioprio = get_current_ioprio();
ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
if (unlikely(ret))
return ret;
req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
return 0;
}
static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,
struct iovec **iovec, bool vectored, bool compat,
struct iov_iter *iter)
{
void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
size_t len = iocb->aio_nbytes;
if (!vectored) {
ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
*iovec = NULL;
return ret;
}
return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat);
}
static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
{
switch (ret) {
case -EIOCBQUEUED:
break;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/*
* There's no easy way to restart the syscall since other AIO's
* may be already running. Just fail this IO with EINTR.
*/
ret = -EINTR;
fallthrough;
default:
req->ki_complete(req, ret);
}
}
static int aio_read(struct kiocb *req, const struct iocb *iocb,
bool vectored, bool compat)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct iov_iter iter;
struct file *file;
int ret;
ret = aio_prep_rw(req, iocb);
if (ret)
return ret;
file = req->ki_filp;
if (unlikely(!(file->f_mode & FMODE_READ)))
return -EBADF;
if (unlikely(!file->f_op->read_iter))
return -EINVAL;
ret = aio_setup_rw(ITER_DEST, iocb, &iovec, vectored, compat, &iter);
if (ret < 0)
return ret;
ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
if (!ret)
aio_rw_done(req, call_read_iter(file, req, &iter));
kfree(iovec);
return ret;
}
static int aio_write(struct kiocb *req, const struct iocb *iocb,
bool vectored, bool compat)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct iov_iter iter;
struct file *file;
int ret;
ret = aio_prep_rw(req, iocb);
if (ret)
return ret;
file = req->ki_filp;
if (unlikely(!(file->f_mode & FMODE_WRITE)))
return -EBADF;
if (unlikely(!file->f_op->write_iter))
return -EINVAL;
ret = aio_setup_rw(ITER_SOURCE, iocb, &iovec, vectored, compat, &iter);
if (ret < 0)
return ret;
ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
if (!ret) {
if (S_ISREG(file_inode(file)->i_mode))
kiocb_start_write(req);
req->ki_flags |= IOCB_WRITE;
aio_rw_done(req, call_write_iter(file, req, &iter));
}
kfree(iovec);
return ret;
}
static void aio_fsync_work(struct work_struct *work)
{
struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);
const struct cred *old_cred = override_creds(iocb->fsync.creds);
iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
revert_creds(old_cred);
put_cred(iocb->fsync.creds);
iocb_put(iocb);
}
static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
bool datasync)
{
if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
iocb->aio_rw_flags))
return -EINVAL;
if (unlikely(!req->file->f_op->fsync))
return -EINVAL;
req->creds = prepare_creds();
if (!req->creds)
return -ENOMEM;
req->datasync = datasync;
INIT_WORK(&req->work, aio_fsync_work);
schedule_work(&req->work);
return 0;
}
static void aio_poll_put_work(struct work_struct *work)
{
struct poll_iocb *req = container_of(work, struct poll_iocb, work);
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
iocb_put(iocb);
}
/*
* Safely lock the waitqueue which the request is on, synchronizing with the
* case where the ->poll() provider decides to free its waitqueue early.
*
* Returns true on success, meaning that req->head->lock was locked, req->wait
* is on req->head, and an RCU read lock was taken. Returns false if the
* request was already removed from its waitqueue (which might no longer exist).
*/
static bool poll_iocb_lock_wq(struct poll_iocb *req)
{
wait_queue_head_t *head;
/*
* While we hold the waitqueue lock and the waitqueue is nonempty,
* wake_up_pollfree() will wait for us. However, taking the waitqueue
* lock in the first place can race with the waitqueue being freed.
*
* We solve this as eventpoll does: by taking advantage of the fact that
* all users of wake_up_pollfree() will RCU-delay the actual free. If
* we enter rcu_read_lock() and see that the pointer to the queue is
* non-NULL, we can then lock it without the memory being freed out from
* under us, then check whether the request is still on the queue.
*
* Keep holding rcu_read_lock() as long as we hold the queue lock, in
* case the caller deletes the entry from the queue, leaving it empty.
* In that case, only RCU prevents the queue memory from being freed.
*/
rcu_read_lock();
head = smp_load_acquire(&req->head);
if (head) {
spin_lock(&head->lock);
if (!list_empty(&req->wait.entry))
return true;
spin_unlock(&head->lock);
}
rcu_read_unlock();
return false;
}
static void poll_iocb_unlock_wq(struct poll_iocb *req)
{
spin_unlock(&req->head->lock);
rcu_read_unlock();
}
static void aio_poll_complete_work(struct work_struct *work)
{
struct poll_iocb *req = container_of(work, struct poll_iocb, work);
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
struct poll_table_struct pt = { ._key = req->events };
struct kioctx *ctx = iocb->ki_ctx;
__poll_t mask = 0;
if (!READ_ONCE(req->cancelled))
mask = vfs_poll(req->file, &pt) & req->events;
/*
* Note that ->ki_cancel callers also delete iocb from active_reqs after
* calling ->ki_cancel. We need the ctx_lock roundtrip here to
* synchronize with them. In the cancellation case the list_del_init
* itself is not actually needed, but harmless so we keep it in to
* avoid further branches in the fast path.
*/
spin_lock_irq(&ctx->ctx_lock);
if (poll_iocb_lock_wq(req)) {
if (!mask && !READ_ONCE(req->cancelled)) {
/*
* The request isn't actually ready to be completed yet.
* Reschedule completion if another wakeup came in.
*/
if (req->work_need_resched) {
schedule_work(&req->work);
req->work_need_resched = false;
} else {
req->work_scheduled = false;
}
poll_iocb_unlock_wq(req);
spin_unlock_irq(&ctx->ctx_lock);
return;
}
list_del_init(&req->wait.entry);
poll_iocb_unlock_wq(req);
} /* else, POLLFREE has freed the waitqueue, so we must complete */
list_del_init(&iocb->ki_list);
iocb->ki_res.res = mangle_poll(mask);
spin_unlock_irq(&ctx->ctx_lock);
iocb_put(iocb);
}
/* assumes we are called with irqs disabled */
static int aio_poll_cancel(struct kiocb *iocb)
{
struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
struct poll_iocb *req = &aiocb->poll;
if (poll_iocb_lock_wq(req)) {
WRITE_ONCE(req->cancelled, true);
if (!req->work_scheduled) {
schedule_work(&aiocb->poll.work);
req->work_scheduled = true;
}
poll_iocb_unlock_wq(req);
} /* else, the request was force-cancelled by POLLFREE already */
return 0;
}
static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
void *key)
{
struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
__poll_t mask = key_to_poll(key);
unsigned long flags;
/* for instances that support it check for an event match first: */
if (mask && !(mask & req->events))
return 0;
/*
* Complete the request inline if possible. This requires that three
* conditions be met:
* 1. An event mask must have been passed. If a plain wakeup was done
* instead, then mask == 0 and we have to call vfs_poll() to get
* the events, so inline completion isn't possible.
* 2. The completion work must not have already been scheduled.
* 3. ctx_lock must not be busy. We have to use trylock because we
* already hold the waitqueue lock, so this inverts the normal
* locking order. Use irqsave/irqrestore because not all
* filesystems (e.g. fuse) call this function with IRQs disabled,
* yet IRQs have to be disabled before ctx_lock is obtained.
*/
if (mask && !req->work_scheduled &&
spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
struct kioctx *ctx = iocb->ki_ctx;
list_del_init(&req->wait.entry);
list_del(&iocb->ki_list);
iocb->ki_res.res = mangle_poll(mask);
if (iocb->ki_eventfd && !eventfd_signal_allowed()) {
iocb = NULL;
INIT_WORK(&req->work, aio_poll_put_work);
schedule_work(&req->work);
}
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
if (iocb)
iocb_put(iocb);
} else {
/*
* Schedule the completion work if needed. If it was already
* scheduled, record that another wakeup came in.
*
* Don't remove the request from the waitqueue here, as it might
* not actually be complete yet (we won't know until vfs_poll()
* is called), and we must not miss any wakeups. POLLFREE is an
* exception to this; see below.
*/
if (req->work_scheduled) {
req->work_need_resched = true;
} else {
schedule_work(&req->work);
req->work_scheduled = true;
}
/*
* If the waitqueue is being freed early but we can't complete
* the request inline, we have to tear down the request as best
* we can. That means immediately removing the request from its
* waitqueue and preventing all further accesses to the
* waitqueue via the request. We also need to schedule the
* completion work (done above). Also mark the request as
* cancelled, to potentially skip an unneeded call to ->poll().
*/
if (mask & POLLFREE) {
WRITE_ONCE(req->cancelled, true);
list_del_init(&req->wait.entry);
/*
* Careful: this *must* be the last step, since as soon
* as req->head is NULL'ed out, the request can be
* completed and freed, since aio_poll_complete_work()
* will no longer need to take the waitqueue lock.
*/
smp_store_release(&req->head, NULL);
}
}
return 1;
}
struct aio_poll_table {
struct poll_table_struct pt;
struct aio_kiocb *iocb;
bool queued;
int error;
};
static void
aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
struct poll_table_struct *p)
{
struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);
/* multiple wait queues per file are not supported */
if (unlikely(pt->queued)) {
pt->error = -EINVAL;
return;
}
pt->queued = true;
pt->error = 0;
pt->iocb->poll.head = head;
add_wait_queue(head, &pt->iocb->poll.wait);
}
static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
{
struct kioctx *ctx = aiocb->ki_ctx;
struct poll_iocb *req = &aiocb->poll;
struct aio_poll_table apt;
bool cancel = false;
__poll_t mask;
/* reject any unknown events outside the normal event mask. */
if ((u16)iocb->aio_buf != iocb->aio_buf)
return -EINVAL;
/* reject fields that are not defined for poll */
if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
return -EINVAL;
INIT_WORK(&req->work, aio_poll_complete_work);
req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
req->head = NULL;
req->cancelled = false;
req->work_scheduled = false;
req->work_need_resched = false;
apt.pt._qproc = aio_poll_queue_proc;
apt.pt._key = req->events;
apt.iocb = aiocb;
apt.queued = false;
apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
/* initialized the list so that we can do list_empty checks */
INIT_LIST_HEAD(&req->wait.entry);
init_waitqueue_func_entry(&req->wait, aio_poll_wake);
mask = vfs_poll(req->file, &apt.pt) & req->events;
spin_lock_irq(&ctx->ctx_lock);
if (likely(apt.queued)) {
bool on_queue = poll_iocb_lock_wq(req);
if (!on_queue || req->work_scheduled) {
/*
* aio_poll_wake() already either scheduled the async
* completion work, or completed the request inline.
*/
if (apt.error) /* unsupported case: multiple queues */
cancel = true;
apt.error = 0;
mask = 0;
}
if (mask || apt.error) {
/* Steal to complete synchronously. */
list_del_init(&req->wait.entry);
} else if (cancel) {
/* Cancel if possible (may be too late though). */
WRITE_ONCE(req->cancelled, true);
} else if (on_queue) {
/*
* Actually waiting for an event, so add the request to
* active_reqs so that it can be cancelled if needed.
*/
list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
aiocb->ki_cancel = aio_poll_cancel;
}
if (on_queue)
poll_iocb_unlock_wq(req);
}
if (mask) { /* no async, we'd stolen it */
aiocb->ki_res.res = mangle_poll(mask);
apt.error = 0;
}
spin_unlock_irq(&ctx->ctx_lock);
if (mask)
iocb_put(aiocb);
return apt.error;
}
static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
struct iocb __user *user_iocb, struct aio_kiocb *req,
bool compat)
{
req->ki_filp = fget(iocb->aio_fildes);
if (unlikely(!req->ki_filp))
return -EBADF;
if (iocb->aio_flags & IOCB_FLAG_RESFD) {
struct eventfd_ctx *eventfd;
/*
* If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
* instance of the file* now. The file descriptor must be
* an eventfd() fd, and will be signaled for each completed
* event using the eventfd_signal() function.
*/
eventfd = eventfd_ctx_fdget(iocb->aio_resfd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
req->ki_eventfd = eventfd;
}
if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {
pr_debug("EFAULT: aio_key\n");
return -EFAULT;
}
req->ki_res.obj = (u64)(unsigned long)user_iocb;
req->ki_res.data = iocb->aio_data;
req->ki_res.res = 0;
req->ki_res.res2 = 0;
switch (iocb->aio_lio_opcode) {
case IOCB_CMD_PREAD:
return aio_read(&req->rw, iocb, false, compat);
case IOCB_CMD_PWRITE:
return aio_write(&req->rw, iocb, false, compat);
case IOCB_CMD_PREADV:
return aio_read(&req->rw, iocb, true, compat);
case IOCB_CMD_PWRITEV:
return aio_write(&req->rw, iocb, true, compat);
case IOCB_CMD_FSYNC:
return aio_fsync(&req->fsync, iocb, false);
case IOCB_CMD_FDSYNC:
return aio_fsync(&req->fsync, iocb, true);
case IOCB_CMD_POLL:
return aio_poll(req, iocb);
default:
pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
return -EINVAL;
}
}
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
bool compat)
{
struct aio_kiocb *req;
struct iocb iocb;
int err;
if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
return -EFAULT;
/* enforce forwards compatibility on users */
if (unlikely(iocb.aio_reserved2)) {
pr_debug("EINVAL: reserve field set\n");
return -EINVAL;
}
/* prevent overflows */
if (unlikely(
(iocb.aio_buf != (unsigned long)iocb.aio_buf) ||
(iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||
((ssize_t)iocb.aio_nbytes < 0)
)) {
pr_debug("EINVAL: overflow check\n");
return -EINVAL;
}
req = aio_get_req(ctx);
if (unlikely(!req))
return -EAGAIN;
err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);
/* Done with the synchronous reference */
iocb_put(req);
/*
* If err is 0, we'd either done aio_complete() ourselves or have
* arranged for that to be done asynchronously. Anything non-zero
* means that we need to destroy req ourselves.
*/
if (unlikely(err)) {
iocb_destroy(req);
put_reqs_available(ctx, 1);
}
return err;
}
/* sys_io_submit:
* Queue the nr iocbs pointed to by iocbpp for processing. Returns
* the number of iocbs queued. May return -EINVAL if the aio_context
* specified by ctx_id is invalid, if nr is < 0, if the iocb at
* *iocbpp[0] is not properly initialized, if the operation specified
* is invalid for the file descriptor in the iocb. May fail with
* -EFAULT if any of the data structures point to invalid data. May
* fail with -EBADF if the file descriptor specified in the first
* iocb is invalid. May fail with -EAGAIN if insufficient resources
* are available to queue any iocbs. Will return 0 if nr is 0. Will
* fail with -ENOSYS if not implemented.
*/
SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
struct iocb __user * __user *, iocbpp)
{
struct kioctx *ctx;
long ret = 0;
int i = 0;
struct blk_plug plug;
if (unlikely(nr < 0))
return -EINVAL;
ctx = lookup_ioctx(ctx_id);
if (unlikely(!ctx)) {
pr_debug("EINVAL: invalid context id\n");
return -EINVAL;
}
if (nr > ctx->nr_events)
nr = ctx->nr_events;
if (nr > AIO_PLUG_THRESHOLD)
blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
struct iocb __user *user_iocb;
if (unlikely(get_user(user_iocb, iocbpp + i))) {
ret = -EFAULT;
break;
}
ret = io_submit_one(ctx, user_iocb, false);
if (ret)
break;
}
if (nr > AIO_PLUG_THRESHOLD)
blk_finish_plug(&plug);
percpu_ref_put(&ctx->users);
return i ? i : ret;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
int, nr, compat_uptr_t __user *, iocbpp)
{
struct kioctx *ctx;
long ret = 0;
int i = 0;
struct blk_plug plug;
if (unlikely(nr < 0))
return -EINVAL;
ctx = lookup_ioctx(ctx_id);
if (unlikely(!ctx)) {
pr_debug("EINVAL: invalid context id\n");
return -EINVAL;
}
if (nr > ctx->nr_events)
nr = ctx->nr_events;
if (nr > AIO_PLUG_THRESHOLD)
blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
compat_uptr_t user_iocb;
if (unlikely(get_user(user_iocb, iocbpp + i))) {
ret = -EFAULT;
break;
}
ret = io_submit_one(ctx, compat_ptr(user_iocb), true);
if (ret)
break;
}
if (nr > AIO_PLUG_THRESHOLD)
blk_finish_plug(&plug);
percpu_ref_put(&ctx->users);
return i ? i : ret;
}
#endif
/* sys_io_cancel:
* Attempts to cancel an iocb previously passed to io_submit. If
* the operation is successfully cancelled, the resulting event is
* copied into the memory pointed to by result without being placed
* into the completion queue and 0 is returned. May fail with
* -EFAULT if any of the data structures pointed to are invalid.
* May fail with -EINVAL if aio_context specified by ctx_id is
* invalid. May fail with -EAGAIN if the iocb specified was not
* cancelled. Will fail with -ENOSYS if not implemented.
*/
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
struct io_event __user *, result)
{
struct kioctx *ctx;
struct aio_kiocb *kiocb;
int ret = -EINVAL;
u32 key;
u64 obj = (u64)(unsigned long)iocb;
if (unlikely(get_user(key, &iocb->aio_key)))
return -EFAULT;
if (unlikely(key != KIOCB_KEY))
return -EINVAL;
ctx = lookup_ioctx(ctx_id);
if (unlikely(!ctx))
return -EINVAL;
spin_lock_irq(&ctx->ctx_lock);
/* TODO: use a hash or array, this sucks. */
list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
if (kiocb->ki_res.obj == obj) {
ret = kiocb->ki_cancel(&kiocb->rw);
list_del_init(&kiocb->ki_list);
break;
}
}
spin_unlock_irq(&ctx->ctx_lock);
if (!ret) {
/*
* The result argument is no longer used - the io_event is
* always delivered via the ring buffer. -EINPROGRESS indicates
* cancellation is progress:
*/
ret = -EINPROGRESS;
}
percpu_ref_put(&ctx->users);
return ret;
}
static long do_io_getevents(aio_context_t ctx_id,
long min_nr,
long nr,
struct io_event __user *events,
struct timespec64 *ts)
{
ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;
struct kioctx *ioctx = lookup_ioctx(ctx_id);
long ret = -EINVAL;
if (likely(ioctx)) {
if (likely(min_nr <= nr && min_nr >= 0))
ret = read_events(ioctx, min_nr, nr, events, until);
percpu_ref_put(&ioctx->users);
}
return ret;
}
/* io_getevents:
* Attempts to read at least min_nr events and up to nr events from
* the completion queue for the aio_context specified by ctx_id. If
* it succeeds, the number of read events is returned. May fail with
* -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
* out of range, if timeout is out of range. May fail with -EFAULT
* if any of the memory specified is invalid. May return 0 or
* < min_nr if the timeout specified by timeout has elapsed
* before sufficient events are available, where timeout == NULL
* specifies an infinite timeout. Note that the timeout pointed to by
* timeout is relative. Will fail with -ENOSYS if not implemented.
*/
#ifdef CONFIG_64BIT
SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
long, min_nr,
long, nr,
struct io_event __user *, events,
struct __kernel_timespec __user *, timeout)
{
struct timespec64 ts;
int ret;
if (timeout && unlikely(get_timespec64(&ts, timeout)))
return -EFAULT;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
if (!ret && signal_pending(current))
ret = -EINTR;
return ret;
}
#endif
struct __aio_sigset {
const sigset_t __user *sigmask;
size_t sigsetsize;
};
SYSCALL_DEFINE6(io_pgetevents,
aio_context_t, ctx_id,
long, min_nr,
long, nr,
struct io_event __user *, events,
struct __kernel_timespec __user *, timeout,
const struct __aio_sigset __user *, usig)
{
struct __aio_sigset ksig = { NULL, };
struct timespec64 ts;
bool interrupted;
int ret;
if (timeout && unlikely(get_timespec64(&ts, timeout)))
return -EFAULT;
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
return -EFAULT;
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
interrupted = signal_pending(current);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;
return ret;
}
#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
SYSCALL_DEFINE6(io_pgetevents_time32,
aio_context_t, ctx_id,
long, min_nr,
long, nr,
struct io_event __user *, events,
struct old_timespec32 __user *, timeout,
const struct __aio_sigset __user *, usig)
{
struct __aio_sigset ksig = { NULL, };
struct timespec64 ts;
bool interrupted;
int ret;
if (timeout && unlikely(get_old_timespec32(&ts, timeout)))
return -EFAULT;
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
return -EFAULT;
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
interrupted = signal_pending(current);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;
return ret;
}
#endif
#if defined(CONFIG_COMPAT_32BIT_TIME)
SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,
__s32, min_nr,
__s32, nr,
struct io_event __user *, events,
struct old_timespec32 __user *, timeout)
{
struct timespec64 t;
int ret;
if (timeout && get_old_timespec32(&t, timeout))
return -EFAULT;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
if (!ret && signal_pending(current))
ret = -EINTR;
return ret;
}
#endif
#ifdef CONFIG_COMPAT
struct __compat_aio_sigset {
compat_uptr_t sigmask;
compat_size_t sigsetsize;
};
#if defined(CONFIG_COMPAT_32BIT_TIME)
COMPAT_SYSCALL_DEFINE6(io_pgetevents,
compat_aio_context_t, ctx_id,
compat_long_t, min_nr,
compat_long_t, nr,
struct io_event __user *, events,
struct old_timespec32 __user *, timeout,
const struct __compat_aio_sigset __user *, usig)
{
struct __compat_aio_sigset ksig = { 0, };
struct timespec64 t;
bool interrupted;
int ret;
if (timeout && get_old_timespec32(&t, timeout))
return -EFAULT;
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
return -EFAULT;
ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
interrupted = signal_pending(current);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;
return ret;
}
#endif
COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
compat_aio_context_t, ctx_id,
compat_long_t, min_nr,
compat_long_t, nr,
struct io_event __user *, events,
struct __kernel_timespec __user *, timeout,
const struct __compat_aio_sigset __user *, usig)
{
struct __compat_aio_sigset ksig = { 0, };
struct timespec64 t;
bool interrupted;
int ret;
if (timeout && get_timespec64(&t, timeout))
return -EFAULT;
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
return -EFAULT;
ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
interrupted = signal_pending(current);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;
return ret;
}
#endif
| linux-master | fs/aio.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/userfaultfd.c
*
* Copyright (C) 2007 Davide Libenzi <[email protected]>
* Copyright (C) 2008-2009 Red Hat, Inc.
* Copyright (C) 2015 Red Hat, Inc.
*
* Some part derived from fs/eventfd.c (anon inode setup) and
* mm/ksm.c (mm hashing).
*/
#include <linux/list.h>
#include <linux/hashtable.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/mm.h>
#include <linux/mm_inline.h>
#include <linux/mmu_notifier.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/file.h>
#include <linux/bug.h>
#include <linux/anon_inodes.h>
#include <linux/syscalls.h>
#include <linux/userfaultfd_k.h>
#include <linux/mempolicy.h>
#include <linux/ioctl.h>
#include <linux/security.h>
#include <linux/hugetlb.h>
#include <linux/swapops.h>
#include <linux/miscdevice.h>
static int sysctl_unprivileged_userfaultfd __read_mostly;
#ifdef CONFIG_SYSCTL
static struct ctl_table vm_userfaultfd_table[] = {
{
.procname = "unprivileged_userfaultfd",
.data = &sysctl_unprivileged_userfaultfd,
.maxlen = sizeof(sysctl_unprivileged_userfaultfd),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{ }
};
#endif
static struct kmem_cache *userfaultfd_ctx_cachep __read_mostly;
/*
* Start with fault_pending_wqh and fault_wqh so they're more likely
* to be in the same cacheline.
*
* Locking order:
* fd_wqh.lock
* fault_pending_wqh.lock
* fault_wqh.lock
* event_wqh.lock
*
* To avoid deadlocks, IRQs must be disabled when taking any of the above locks,
* since fd_wqh.lock is taken by aio_poll() while it's holding a lock that's
* also taken in IRQ context.
*/
struct userfaultfd_ctx {
/* waitqueue head for the pending (i.e. not read) userfaults */
wait_queue_head_t fault_pending_wqh;
/* waitqueue head for the userfaults */
wait_queue_head_t fault_wqh;
/* waitqueue head for the pseudo fd to wakeup poll/read */
wait_queue_head_t fd_wqh;
/* waitqueue head for events */
wait_queue_head_t event_wqh;
/* a refile sequence protected by fault_pending_wqh lock */
seqcount_spinlock_t refile_seq;
/* pseudo fd refcounting */
refcount_t refcount;
/* userfaultfd syscall flags */
unsigned int flags;
/* features requested from the userspace */
unsigned int features;
/* released */
bool released;
/* memory mappings are changing because of non-cooperative event */
atomic_t mmap_changing;
/* mm with one ore more vmas attached to this userfaultfd_ctx */
struct mm_struct *mm;
};
struct userfaultfd_fork_ctx {
struct userfaultfd_ctx *orig;
struct userfaultfd_ctx *new;
struct list_head list;
};
struct userfaultfd_unmap_ctx {
struct userfaultfd_ctx *ctx;
unsigned long start;
unsigned long end;
struct list_head list;
};
struct userfaultfd_wait_queue {
struct uffd_msg msg;
wait_queue_entry_t wq;
struct userfaultfd_ctx *ctx;
bool waken;
};
struct userfaultfd_wake_range {
unsigned long start;
unsigned long len;
};
/* internal indication that UFFD_API ioctl was successfully executed */
#define UFFD_FEATURE_INITIALIZED (1u << 31)
static bool userfaultfd_is_initialized(struct userfaultfd_ctx *ctx)
{
return ctx->features & UFFD_FEATURE_INITIALIZED;
}
/*
* Whether WP_UNPOPULATED is enabled on the uffd context. It is only
* meaningful when userfaultfd_wp()==true on the vma and when it's
* anonymous.
*/
bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma)
{
struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
if (!ctx)
return false;
return ctx->features & UFFD_FEATURE_WP_UNPOPULATED;
}
static void userfaultfd_set_vm_flags(struct vm_area_struct *vma,
vm_flags_t flags)
{
const bool uffd_wp_changed = (vma->vm_flags ^ flags) & VM_UFFD_WP;
vm_flags_reset(vma, flags);
/*
* For shared mappings, we want to enable writenotify while
* userfaultfd-wp is enabled (see vma_wants_writenotify()). We'll simply
* recalculate vma->vm_page_prot whenever userfaultfd-wp changes.
*/
if ((vma->vm_flags & VM_SHARED) && uffd_wp_changed)
vma_set_page_prot(vma);
}
static int userfaultfd_wake_function(wait_queue_entry_t *wq, unsigned mode,
int wake_flags, void *key)
{
struct userfaultfd_wake_range *range = key;
int ret;
struct userfaultfd_wait_queue *uwq;
unsigned long start, len;
uwq = container_of(wq, struct userfaultfd_wait_queue, wq);
ret = 0;
/* len == 0 means wake all */
start = range->start;
len = range->len;
if (len && (start > uwq->msg.arg.pagefault.address ||
start + len <= uwq->msg.arg.pagefault.address))
goto out;
WRITE_ONCE(uwq->waken, true);
/*
* The Program-Order guarantees provided by the scheduler
* ensure uwq->waken is visible before the task is woken.
*/
ret = wake_up_state(wq->private, mode);
if (ret) {
/*
* Wake only once, autoremove behavior.
*
* After the effect of list_del_init is visible to the other
* CPUs, the waitqueue may disappear from under us, see the
* !list_empty_careful() in handle_userfault().
*
* try_to_wake_up() has an implicit smp_mb(), and the
* wq->private is read before calling the extern function
* "wake_up_state" (which in turns calls try_to_wake_up).
*/
list_del_init(&wq->entry);
}
out:
return ret;
}
/**
* userfaultfd_ctx_get - Acquires a reference to the internal userfaultfd
* context.
* @ctx: [in] Pointer to the userfaultfd context.
*/
static void userfaultfd_ctx_get(struct userfaultfd_ctx *ctx)
{
refcount_inc(&ctx->refcount);
}
/**
* userfaultfd_ctx_put - Releases a reference to the internal userfaultfd
* context.
* @ctx: [in] Pointer to userfaultfd context.
*
* The userfaultfd context reference must have been previously acquired either
* with userfaultfd_ctx_get() or userfaultfd_ctx_fdget().
*/
static void userfaultfd_ctx_put(struct userfaultfd_ctx *ctx)
{
if (refcount_dec_and_test(&ctx->refcount)) {
VM_BUG_ON(spin_is_locked(&ctx->fault_pending_wqh.lock));
VM_BUG_ON(waitqueue_active(&ctx->fault_pending_wqh));
VM_BUG_ON(spin_is_locked(&ctx->fault_wqh.lock));
VM_BUG_ON(waitqueue_active(&ctx->fault_wqh));
VM_BUG_ON(spin_is_locked(&ctx->event_wqh.lock));
VM_BUG_ON(waitqueue_active(&ctx->event_wqh));
VM_BUG_ON(spin_is_locked(&ctx->fd_wqh.lock));
VM_BUG_ON(waitqueue_active(&ctx->fd_wqh));
mmdrop(ctx->mm);
kmem_cache_free(userfaultfd_ctx_cachep, ctx);
}
}
static inline void msg_init(struct uffd_msg *msg)
{
BUILD_BUG_ON(sizeof(struct uffd_msg) != 32);
/*
* Must use memset to zero out the paddings or kernel data is
* leaked to userland.
*/
memset(msg, 0, sizeof(struct uffd_msg));
}
static inline struct uffd_msg userfault_msg(unsigned long address,
unsigned long real_address,
unsigned int flags,
unsigned long reason,
unsigned int features)
{
struct uffd_msg msg;
msg_init(&msg);
msg.event = UFFD_EVENT_PAGEFAULT;
msg.arg.pagefault.address = (features & UFFD_FEATURE_EXACT_ADDRESS) ?
real_address : address;
/*
* These flags indicate why the userfault occurred:
* - UFFD_PAGEFAULT_FLAG_WP indicates a write protect fault.
* - UFFD_PAGEFAULT_FLAG_MINOR indicates a minor fault.
* - Neither of these flags being set indicates a MISSING fault.
*
* Separately, UFFD_PAGEFAULT_FLAG_WRITE indicates it was a write
* fault. Otherwise, it was a read fault.
*/
if (flags & FAULT_FLAG_WRITE)
msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WRITE;
if (reason & VM_UFFD_WP)
msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WP;
if (reason & VM_UFFD_MINOR)
msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_MINOR;
if (features & UFFD_FEATURE_THREAD_ID)
msg.arg.pagefault.feat.ptid = task_pid_vnr(current);
return msg;
}
#ifdef CONFIG_HUGETLB_PAGE
/*
* Same functionality as userfaultfd_must_wait below with modifications for
* hugepmd ranges.
*/
static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
struct vm_fault *vmf,
unsigned long reason)
{
struct vm_area_struct *vma = vmf->vma;
pte_t *ptep, pte;
bool ret = true;
assert_fault_locked(vmf);
ptep = hugetlb_walk(vma, vmf->address, vma_mmu_pagesize(vma));
if (!ptep)
goto out;
ret = false;
pte = huge_ptep_get(ptep);
/*
* Lockless access: we're in a wait_event so it's ok if it
* changes under us. PTE markers should be handled the same as none
* ptes here.
*/
if (huge_pte_none_mostly(pte))
ret = true;
if (!huge_pte_write(pte) && (reason & VM_UFFD_WP))
ret = true;
out:
return ret;
}
#else
static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
struct vm_fault *vmf,
unsigned long reason)
{
return false; /* should never get here */
}
#endif /* CONFIG_HUGETLB_PAGE */
/*
* Verify the pagetables are still not ok after having reigstered into
* the fault_pending_wqh to avoid userland having to UFFDIO_WAKE any
* userfault that has already been resolved, if userfaultfd_read and
* UFFDIO_COPY|ZEROPAGE are being run simultaneously on two different
* threads.
*/
static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
struct vm_fault *vmf,
unsigned long reason)
{
struct mm_struct *mm = ctx->mm;
unsigned long address = vmf->address;
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd, _pmd;
pte_t *pte;
pte_t ptent;
bool ret = true;
assert_fault_locked(vmf);
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
goto out;
p4d = p4d_offset(pgd, address);
if (!p4d_present(*p4d))
goto out;
pud = pud_offset(p4d, address);
if (!pud_present(*pud))
goto out;
pmd = pmd_offset(pud, address);
again:
_pmd = pmdp_get_lockless(pmd);
if (pmd_none(_pmd))
goto out;
ret = false;
if (!pmd_present(_pmd) || pmd_devmap(_pmd))
goto out;
if (pmd_trans_huge(_pmd)) {
if (!pmd_write(_pmd) && (reason & VM_UFFD_WP))
ret = true;
goto out;
}
pte = pte_offset_map(pmd, address);
if (!pte) {
ret = true;
goto again;
}
/*
* Lockless access: we're in a wait_event so it's ok if it
* changes under us. PTE markers should be handled the same as none
* ptes here.
*/
ptent = ptep_get(pte);
if (pte_none_mostly(ptent))
ret = true;
if (!pte_write(ptent) && (reason & VM_UFFD_WP))
ret = true;
pte_unmap(pte);
out:
return ret;
}
static inline unsigned int userfaultfd_get_blocking_state(unsigned int flags)
{
if (flags & FAULT_FLAG_INTERRUPTIBLE)
return TASK_INTERRUPTIBLE;
if (flags & FAULT_FLAG_KILLABLE)
return TASK_KILLABLE;
return TASK_UNINTERRUPTIBLE;
}
/*
* The locking rules involved in returning VM_FAULT_RETRY depending on
* FAULT_FLAG_ALLOW_RETRY, FAULT_FLAG_RETRY_NOWAIT and
* FAULT_FLAG_KILLABLE are not straightforward. The "Caution"
* recommendation in __lock_page_or_retry is not an understatement.
*
* If FAULT_FLAG_ALLOW_RETRY is set, the mmap_lock must be released
* before returning VM_FAULT_RETRY only if FAULT_FLAG_RETRY_NOWAIT is
* not set.
*
* If FAULT_FLAG_ALLOW_RETRY is set but FAULT_FLAG_KILLABLE is not
* set, VM_FAULT_RETRY can still be returned if and only if there are
* fatal_signal_pending()s, and the mmap_lock must be released before
* returning it.
*/
vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
{
struct vm_area_struct *vma = vmf->vma;
struct mm_struct *mm = vma->vm_mm;
struct userfaultfd_ctx *ctx;
struct userfaultfd_wait_queue uwq;
vm_fault_t ret = VM_FAULT_SIGBUS;
bool must_wait;
unsigned int blocking_state;
/*
* We don't do userfault handling for the final child pid update.
*
* We also don't do userfault handling during
* coredumping. hugetlbfs has the special
* hugetlb_follow_page_mask() to skip missing pages in the
* FOLL_DUMP case, anon memory also checks for FOLL_DUMP with
* the no_page_table() helper in follow_page_mask(), but the
* shmem_vm_ops->fault method is invoked even during
* coredumping and it ends up here.
*/
if (current->flags & (PF_EXITING|PF_DUMPCORE))
goto out;
assert_fault_locked(vmf);
ctx = vma->vm_userfaultfd_ctx.ctx;
if (!ctx)
goto out;
BUG_ON(ctx->mm != mm);
/* Any unrecognized flag is a bug. */
VM_BUG_ON(reason & ~__VM_UFFD_FLAGS);
/* 0 or > 1 flags set is a bug; we expect exactly 1. */
VM_BUG_ON(!reason || (reason & (reason - 1)));
if (ctx->features & UFFD_FEATURE_SIGBUS)
goto out;
if (!(vmf->flags & FAULT_FLAG_USER) && (ctx->flags & UFFD_USER_MODE_ONLY))
goto out;
/*
* If it's already released don't get it. This avoids to loop
* in __get_user_pages if userfaultfd_release waits on the
* caller of handle_userfault to release the mmap_lock.
*/
if (unlikely(READ_ONCE(ctx->released))) {
/*
* Don't return VM_FAULT_SIGBUS in this case, so a non
* cooperative manager can close the uffd after the
* last UFFDIO_COPY, without risking to trigger an
* involuntary SIGBUS if the process was starting the
* userfaultfd while the userfaultfd was still armed
* (but after the last UFFDIO_COPY). If the uffd
* wasn't already closed when the userfault reached
* this point, that would normally be solved by
* userfaultfd_must_wait returning 'false'.
*
* If we were to return VM_FAULT_SIGBUS here, the non
* cooperative manager would be instead forced to
* always call UFFDIO_UNREGISTER before it can safely
* close the uffd.
*/
ret = VM_FAULT_NOPAGE;
goto out;
}
/*
* Check that we can return VM_FAULT_RETRY.
*
* NOTE: it should become possible to return VM_FAULT_RETRY
* even if FAULT_FLAG_TRIED is set without leading to gup()
* -EBUSY failures, if the userfaultfd is to be extended for
* VM_UFFD_WP tracking and we intend to arm the userfault
* without first stopping userland access to the memory. For
* VM_UFFD_MISSING userfaults this is enough for now.
*/
if (unlikely(!(vmf->flags & FAULT_FLAG_ALLOW_RETRY))) {
/*
* Validate the invariant that nowait must allow retry
* to be sure not to return SIGBUS erroneously on
* nowait invocations.
*/
BUG_ON(vmf->flags & FAULT_FLAG_RETRY_NOWAIT);
#ifdef CONFIG_DEBUG_VM
if (printk_ratelimit()) {
printk(KERN_WARNING
"FAULT_FLAG_ALLOW_RETRY missing %x\n",
vmf->flags);
dump_stack();
}
#endif
goto out;
}
/*
* Handle nowait, not much to do other than tell it to retry
* and wait.
*/
ret = VM_FAULT_RETRY;
if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
goto out;
/* take the reference before dropping the mmap_lock */
userfaultfd_ctx_get(ctx);
init_waitqueue_func_entry(&uwq.wq, userfaultfd_wake_function);
uwq.wq.private = current;
uwq.msg = userfault_msg(vmf->address, vmf->real_address, vmf->flags,
reason, ctx->features);
uwq.ctx = ctx;
uwq.waken = false;
blocking_state = userfaultfd_get_blocking_state(vmf->flags);
/*
* Take the vma lock now, in order to safely call
* userfaultfd_huge_must_wait() later. Since acquiring the
* (sleepable) vma lock can modify the current task state, that
* must be before explicitly calling set_current_state().
*/
if (is_vm_hugetlb_page(vma))
hugetlb_vma_lock_read(vma);
spin_lock_irq(&ctx->fault_pending_wqh.lock);
/*
* After the __add_wait_queue the uwq is visible to userland
* through poll/read().
*/
__add_wait_queue(&ctx->fault_pending_wqh, &uwq.wq);
/*
* The smp_mb() after __set_current_state prevents the reads
* following the spin_unlock to happen before the list_add in
* __add_wait_queue.
*/
set_current_state(blocking_state);
spin_unlock_irq(&ctx->fault_pending_wqh.lock);
if (!is_vm_hugetlb_page(vma))
must_wait = userfaultfd_must_wait(ctx, vmf, reason);
else
must_wait = userfaultfd_huge_must_wait(ctx, vmf, reason);
if (is_vm_hugetlb_page(vma))
hugetlb_vma_unlock_read(vma);
release_fault_lock(vmf);
if (likely(must_wait && !READ_ONCE(ctx->released))) {
wake_up_poll(&ctx->fd_wqh, EPOLLIN);
schedule();
}
__set_current_state(TASK_RUNNING);
/*
* Here we race with the list_del; list_add in
* userfaultfd_ctx_read(), however because we don't ever run
* list_del_init() to refile across the two lists, the prev
* and next pointers will never point to self. list_add also
* would never let any of the two pointers to point to
* self. So list_empty_careful won't risk to see both pointers
* pointing to self at any time during the list refile. The
* only case where list_del_init() is called is the full
* removal in the wake function and there we don't re-list_add
* and it's fine not to block on the spinlock. The uwq on this
* kernel stack can be released after the list_del_init.
*/
if (!list_empty_careful(&uwq.wq.entry)) {
spin_lock_irq(&ctx->fault_pending_wqh.lock);
/*
* No need of list_del_init(), the uwq on the stack
* will be freed shortly anyway.
*/
list_del(&uwq.wq.entry);
spin_unlock_irq(&ctx->fault_pending_wqh.lock);
}
/*
* ctx may go away after this if the userfault pseudo fd is
* already released.
*/
userfaultfd_ctx_put(ctx);
out:
return ret;
}
static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
struct userfaultfd_wait_queue *ewq)
{
struct userfaultfd_ctx *release_new_ctx;
if (WARN_ON_ONCE(current->flags & PF_EXITING))
goto out;
ewq->ctx = ctx;
init_waitqueue_entry(&ewq->wq, current);
release_new_ctx = NULL;
spin_lock_irq(&ctx->event_wqh.lock);
/*
* After the __add_wait_queue the uwq is visible to userland
* through poll/read().
*/
__add_wait_queue(&ctx->event_wqh, &ewq->wq);
for (;;) {
set_current_state(TASK_KILLABLE);
if (ewq->msg.event == 0)
break;
if (READ_ONCE(ctx->released) ||
fatal_signal_pending(current)) {
/*
* &ewq->wq may be queued in fork_event, but
* __remove_wait_queue ignores the head
* parameter. It would be a problem if it
* didn't.
*/
__remove_wait_queue(&ctx->event_wqh, &ewq->wq);
if (ewq->msg.event == UFFD_EVENT_FORK) {
struct userfaultfd_ctx *new;
new = (struct userfaultfd_ctx *)
(unsigned long)
ewq->msg.arg.reserved.reserved1;
release_new_ctx = new;
}
break;
}
spin_unlock_irq(&ctx->event_wqh.lock);
wake_up_poll(&ctx->fd_wqh, EPOLLIN);
schedule();
spin_lock_irq(&ctx->event_wqh.lock);
}
__set_current_state(TASK_RUNNING);
spin_unlock_irq(&ctx->event_wqh.lock);
if (release_new_ctx) {
struct vm_area_struct *vma;
struct mm_struct *mm = release_new_ctx->mm;
VMA_ITERATOR(vmi, mm, 0);
/* the various vma->vm_userfaultfd_ctx still points to it */
mmap_write_lock(mm);
for_each_vma(vmi, vma) {
if (vma->vm_userfaultfd_ctx.ctx == release_new_ctx) {
vma_start_write(vma);
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
userfaultfd_set_vm_flags(vma,
vma->vm_flags & ~__VM_UFFD_FLAGS);
}
}
mmap_write_unlock(mm);
userfaultfd_ctx_put(release_new_ctx);
}
/*
* ctx may go away after this if the userfault pseudo fd is
* already released.
*/
out:
atomic_dec(&ctx->mmap_changing);
VM_BUG_ON(atomic_read(&ctx->mmap_changing) < 0);
userfaultfd_ctx_put(ctx);
}
static void userfaultfd_event_complete(struct userfaultfd_ctx *ctx,
struct userfaultfd_wait_queue *ewq)
{
ewq->msg.event = 0;
wake_up_locked(&ctx->event_wqh);
__remove_wait_queue(&ctx->event_wqh, &ewq->wq);
}
int dup_userfaultfd(struct vm_area_struct *vma, struct list_head *fcs)
{
struct userfaultfd_ctx *ctx = NULL, *octx;
struct userfaultfd_fork_ctx *fctx;
octx = vma->vm_userfaultfd_ctx.ctx;
if (!octx || !(octx->features & UFFD_FEATURE_EVENT_FORK)) {
vma_start_write(vma);
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
userfaultfd_set_vm_flags(vma, vma->vm_flags & ~__VM_UFFD_FLAGS);
return 0;
}
list_for_each_entry(fctx, fcs, list)
if (fctx->orig == octx) {
ctx = fctx->new;
break;
}
if (!ctx) {
fctx = kmalloc(sizeof(*fctx), GFP_KERNEL);
if (!fctx)
return -ENOMEM;
ctx = kmem_cache_alloc(userfaultfd_ctx_cachep, GFP_KERNEL);
if (!ctx) {
kfree(fctx);
return -ENOMEM;
}
refcount_set(&ctx->refcount, 1);
ctx->flags = octx->flags;
ctx->features = octx->features;
ctx->released = false;
atomic_set(&ctx->mmap_changing, 0);
ctx->mm = vma->vm_mm;
mmgrab(ctx->mm);
userfaultfd_ctx_get(octx);
atomic_inc(&octx->mmap_changing);
fctx->orig = octx;
fctx->new = ctx;
list_add_tail(&fctx->list, fcs);
}
vma->vm_userfaultfd_ctx.ctx = ctx;
return 0;
}
static void dup_fctx(struct userfaultfd_fork_ctx *fctx)
{
struct userfaultfd_ctx *ctx = fctx->orig;
struct userfaultfd_wait_queue ewq;
msg_init(&ewq.msg);
ewq.msg.event = UFFD_EVENT_FORK;
ewq.msg.arg.reserved.reserved1 = (unsigned long)fctx->new;
userfaultfd_event_wait_completion(ctx, &ewq);
}
void dup_userfaultfd_complete(struct list_head *fcs)
{
struct userfaultfd_fork_ctx *fctx, *n;
list_for_each_entry_safe(fctx, n, fcs, list) {
dup_fctx(fctx);
list_del(&fctx->list);
kfree(fctx);
}
}
void mremap_userfaultfd_prep(struct vm_area_struct *vma,
struct vm_userfaultfd_ctx *vm_ctx)
{
struct userfaultfd_ctx *ctx;
ctx = vma->vm_userfaultfd_ctx.ctx;
if (!ctx)
return;
if (ctx->features & UFFD_FEATURE_EVENT_REMAP) {
vm_ctx->ctx = ctx;
userfaultfd_ctx_get(ctx);
atomic_inc(&ctx->mmap_changing);
} else {
/* Drop uffd context if remap feature not enabled */
vma_start_write(vma);
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
userfaultfd_set_vm_flags(vma, vma->vm_flags & ~__VM_UFFD_FLAGS);
}
}
void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
unsigned long from, unsigned long to,
unsigned long len)
{
struct userfaultfd_ctx *ctx = vm_ctx->ctx;
struct userfaultfd_wait_queue ewq;
if (!ctx)
return;
if (to & ~PAGE_MASK) {
userfaultfd_ctx_put(ctx);
return;
}
msg_init(&ewq.msg);
ewq.msg.event = UFFD_EVENT_REMAP;
ewq.msg.arg.remap.from = from;
ewq.msg.arg.remap.to = to;
ewq.msg.arg.remap.len = len;
userfaultfd_event_wait_completion(ctx, &ewq);
}
bool userfaultfd_remove(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
struct userfaultfd_ctx *ctx;
struct userfaultfd_wait_queue ewq;
ctx = vma->vm_userfaultfd_ctx.ctx;
if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_REMOVE))
return true;
userfaultfd_ctx_get(ctx);
atomic_inc(&ctx->mmap_changing);
mmap_read_unlock(mm);
msg_init(&ewq.msg);
ewq.msg.event = UFFD_EVENT_REMOVE;
ewq.msg.arg.remove.start = start;
ewq.msg.arg.remove.end = end;
userfaultfd_event_wait_completion(ctx, &ewq);
return false;
}
static bool has_unmap_ctx(struct userfaultfd_ctx *ctx, struct list_head *unmaps,
unsigned long start, unsigned long end)
{
struct userfaultfd_unmap_ctx *unmap_ctx;
list_for_each_entry(unmap_ctx, unmaps, list)
if (unmap_ctx->ctx == ctx && unmap_ctx->start == start &&
unmap_ctx->end == end)
return true;
return false;
}
int userfaultfd_unmap_prep(struct vm_area_struct *vma, unsigned long start,
unsigned long end, struct list_head *unmaps)
{
struct userfaultfd_unmap_ctx *unmap_ctx;
struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_UNMAP) ||
has_unmap_ctx(ctx, unmaps, start, end))
return 0;
unmap_ctx = kzalloc(sizeof(*unmap_ctx), GFP_KERNEL);
if (!unmap_ctx)
return -ENOMEM;
userfaultfd_ctx_get(ctx);
atomic_inc(&ctx->mmap_changing);
unmap_ctx->ctx = ctx;
unmap_ctx->start = start;
unmap_ctx->end = end;
list_add_tail(&unmap_ctx->list, unmaps);
return 0;
}
void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf)
{
struct userfaultfd_unmap_ctx *ctx, *n;
struct userfaultfd_wait_queue ewq;
list_for_each_entry_safe(ctx, n, uf, list) {
msg_init(&ewq.msg);
ewq.msg.event = UFFD_EVENT_UNMAP;
ewq.msg.arg.remove.start = ctx->start;
ewq.msg.arg.remove.end = ctx->end;
userfaultfd_event_wait_completion(ctx->ctx, &ewq);
list_del(&ctx->list);
kfree(ctx);
}
}
static int userfaultfd_release(struct inode *inode, struct file *file)
{
struct userfaultfd_ctx *ctx = file->private_data;
struct mm_struct *mm = ctx->mm;
struct vm_area_struct *vma, *prev;
/* len == 0 means wake all */
struct userfaultfd_wake_range range = { .len = 0, };
unsigned long new_flags;
VMA_ITERATOR(vmi, mm, 0);
WRITE_ONCE(ctx->released, true);
if (!mmget_not_zero(mm))
goto wakeup;
/*
* Flush page faults out of all CPUs. NOTE: all page faults
* must be retried without returning VM_FAULT_SIGBUS if
* userfaultfd_ctx_get() succeeds but vma->vma_userfault_ctx
* changes while handle_userfault released the mmap_lock. So
* it's critical that released is set to true (above), before
* taking the mmap_lock for writing.
*/
mmap_write_lock(mm);
prev = NULL;
for_each_vma(vmi, vma) {
cond_resched();
BUG_ON(!!vma->vm_userfaultfd_ctx.ctx ^
!!(vma->vm_flags & __VM_UFFD_FLAGS));
if (vma->vm_userfaultfd_ctx.ctx != ctx) {
prev = vma;
continue;
}
new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
prev = vma_merge(&vmi, mm, prev, vma->vm_start, vma->vm_end,
new_flags, vma->anon_vma,
vma->vm_file, vma->vm_pgoff,
vma_policy(vma),
NULL_VM_UFFD_CTX, anon_vma_name(vma));
if (prev) {
vma = prev;
} else {
prev = vma;
}
vma_start_write(vma);
userfaultfd_set_vm_flags(vma, new_flags);
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
}
mmap_write_unlock(mm);
mmput(mm);
wakeup:
/*
* After no new page faults can wait on this fault_*wqh, flush
* the last page faults that may have been already waiting on
* the fault_*wqh.
*/
spin_lock_irq(&ctx->fault_pending_wqh.lock);
__wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL, &range);
__wake_up(&ctx->fault_wqh, TASK_NORMAL, 1, &range);
spin_unlock_irq(&ctx->fault_pending_wqh.lock);
/* Flush pending events that may still wait on event_wqh */
wake_up_all(&ctx->event_wqh);
wake_up_poll(&ctx->fd_wqh, EPOLLHUP);
userfaultfd_ctx_put(ctx);
return 0;
}
/* fault_pending_wqh.lock must be hold by the caller */
static inline struct userfaultfd_wait_queue *find_userfault_in(
wait_queue_head_t *wqh)
{
wait_queue_entry_t *wq;
struct userfaultfd_wait_queue *uwq;
lockdep_assert_held(&wqh->lock);
uwq = NULL;
if (!waitqueue_active(wqh))
goto out;
/* walk in reverse to provide FIFO behavior to read userfaults */
wq = list_last_entry(&wqh->head, typeof(*wq), entry);
uwq = container_of(wq, struct userfaultfd_wait_queue, wq);
out:
return uwq;
}
static inline struct userfaultfd_wait_queue *find_userfault(
struct userfaultfd_ctx *ctx)
{
return find_userfault_in(&ctx->fault_pending_wqh);
}
static inline struct userfaultfd_wait_queue *find_userfault_evt(
struct userfaultfd_ctx *ctx)
{
return find_userfault_in(&ctx->event_wqh);
}
static __poll_t userfaultfd_poll(struct file *file, poll_table *wait)
{
struct userfaultfd_ctx *ctx = file->private_data;
__poll_t ret;
poll_wait(file, &ctx->fd_wqh, wait);
if (!userfaultfd_is_initialized(ctx))
return EPOLLERR;
/*
* poll() never guarantees that read won't block.
* userfaults can be waken before they're read().
*/
if (unlikely(!(file->f_flags & O_NONBLOCK)))
return EPOLLERR;
/*
* lockless access to see if there are pending faults
* __pollwait last action is the add_wait_queue but
* the spin_unlock would allow the waitqueue_active to
* pass above the actual list_add inside
* add_wait_queue critical section. So use a full
* memory barrier to serialize the list_add write of
* add_wait_queue() with the waitqueue_active read
* below.
*/
ret = 0;
smp_mb();
if (waitqueue_active(&ctx->fault_pending_wqh))
ret = EPOLLIN;
else if (waitqueue_active(&ctx->event_wqh))
ret = EPOLLIN;
return ret;
}
static const struct file_operations userfaultfd_fops;
static int resolve_userfault_fork(struct userfaultfd_ctx *new,
struct inode *inode,
struct uffd_msg *msg)
{
int fd;
fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, new,
O_RDONLY | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode);
if (fd < 0)
return fd;
msg->arg.reserved.reserved1 = 0;
msg->arg.fork.ufd = fd;
return 0;
}
static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait,
struct uffd_msg *msg, struct inode *inode)
{
ssize_t ret;
DECLARE_WAITQUEUE(wait, current);
struct userfaultfd_wait_queue *uwq;
/*
* Handling fork event requires sleeping operations, so
* we drop the event_wqh lock, then do these ops, then
* lock it back and wake up the waiter. While the lock is
* dropped the ewq may go away so we keep track of it
* carefully.
*/
LIST_HEAD(fork_event);
struct userfaultfd_ctx *fork_nctx = NULL;
/* always take the fd_wqh lock before the fault_pending_wqh lock */
spin_lock_irq(&ctx->fd_wqh.lock);
__add_wait_queue(&ctx->fd_wqh, &wait);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
spin_lock(&ctx->fault_pending_wqh.lock);
uwq = find_userfault(ctx);
if (uwq) {
/*
* Use a seqcount to repeat the lockless check
* in wake_userfault() to avoid missing
* wakeups because during the refile both
* waitqueue could become empty if this is the
* only userfault.
*/
write_seqcount_begin(&ctx->refile_seq);
/*
* The fault_pending_wqh.lock prevents the uwq
* to disappear from under us.
*
* Refile this userfault from
* fault_pending_wqh to fault_wqh, it's not
* pending anymore after we read it.
*
* Use list_del() by hand (as
* userfaultfd_wake_function also uses
* list_del_init() by hand) to be sure nobody
* changes __remove_wait_queue() to use
* list_del_init() in turn breaking the
* !list_empty_careful() check in
* handle_userfault(). The uwq->wq.head list
* must never be empty at any time during the
* refile, or the waitqueue could disappear
* from under us. The "wait_queue_head_t"
* parameter of __remove_wait_queue() is unused
* anyway.
*/
list_del(&uwq->wq.entry);
add_wait_queue(&ctx->fault_wqh, &uwq->wq);
write_seqcount_end(&ctx->refile_seq);
/* careful to always initialize msg if ret == 0 */
*msg = uwq->msg;
spin_unlock(&ctx->fault_pending_wqh.lock);
ret = 0;
break;
}
spin_unlock(&ctx->fault_pending_wqh.lock);
spin_lock(&ctx->event_wqh.lock);
uwq = find_userfault_evt(ctx);
if (uwq) {
*msg = uwq->msg;
if (uwq->msg.event == UFFD_EVENT_FORK) {
fork_nctx = (struct userfaultfd_ctx *)
(unsigned long)
uwq->msg.arg.reserved.reserved1;
list_move(&uwq->wq.entry, &fork_event);
/*
* fork_nctx can be freed as soon as
* we drop the lock, unless we take a
* reference on it.
*/
userfaultfd_ctx_get(fork_nctx);
spin_unlock(&ctx->event_wqh.lock);
ret = 0;
break;
}
userfaultfd_event_complete(ctx, uwq);
spin_unlock(&ctx->event_wqh.lock);
ret = 0;
break;
}
spin_unlock(&ctx->event_wqh.lock);
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
if (no_wait) {
ret = -EAGAIN;
break;
}
spin_unlock_irq(&ctx->fd_wqh.lock);
schedule();
spin_lock_irq(&ctx->fd_wqh.lock);
}
__remove_wait_queue(&ctx->fd_wqh, &wait);
__set_current_state(TASK_RUNNING);
spin_unlock_irq(&ctx->fd_wqh.lock);
if (!ret && msg->event == UFFD_EVENT_FORK) {
ret = resolve_userfault_fork(fork_nctx, inode, msg);
spin_lock_irq(&ctx->event_wqh.lock);
if (!list_empty(&fork_event)) {
/*
* The fork thread didn't abort, so we can
* drop the temporary refcount.
*/
userfaultfd_ctx_put(fork_nctx);
uwq = list_first_entry(&fork_event,
typeof(*uwq),
wq.entry);
/*
* If fork_event list wasn't empty and in turn
* the event wasn't already released by fork
* (the event is allocated on fork kernel
* stack), put the event back to its place in
* the event_wq. fork_event head will be freed
* as soon as we return so the event cannot
* stay queued there no matter the current
* "ret" value.
*/
list_del(&uwq->wq.entry);
__add_wait_queue(&ctx->event_wqh, &uwq->wq);
/*
* Leave the event in the waitqueue and report
* error to userland if we failed to resolve
* the userfault fork.
*/
if (likely(!ret))
userfaultfd_event_complete(ctx, uwq);
} else {
/*
* Here the fork thread aborted and the
* refcount from the fork thread on fork_nctx
* has already been released. We still hold
* the reference we took before releasing the
* lock above. If resolve_userfault_fork
* failed we've to drop it because the
* fork_nctx has to be freed in such case. If
* it succeeded we'll hold it because the new
* uffd references it.
*/
if (ret)
userfaultfd_ctx_put(fork_nctx);
}
spin_unlock_irq(&ctx->event_wqh.lock);
}
return ret;
}
static ssize_t userfaultfd_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct userfaultfd_ctx *ctx = file->private_data;
ssize_t _ret, ret = 0;
struct uffd_msg msg;
int no_wait = file->f_flags & O_NONBLOCK;
struct inode *inode = file_inode(file);
if (!userfaultfd_is_initialized(ctx))
return -EINVAL;
for (;;) {
if (count < sizeof(msg))
return ret ? ret : -EINVAL;
_ret = userfaultfd_ctx_read(ctx, no_wait, &msg, inode);
if (_ret < 0)
return ret ? ret : _ret;
if (copy_to_user((__u64 __user *) buf, &msg, sizeof(msg)))
return ret ? ret : -EFAULT;
ret += sizeof(msg);
buf += sizeof(msg);
count -= sizeof(msg);
/*
* Allow to read more than one fault at time but only
* block if waiting for the very first one.
*/
no_wait = O_NONBLOCK;
}
}
static void __wake_userfault(struct userfaultfd_ctx *ctx,
struct userfaultfd_wake_range *range)
{
spin_lock_irq(&ctx->fault_pending_wqh.lock);
/* wake all in the range and autoremove */
if (waitqueue_active(&ctx->fault_pending_wqh))
__wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL,
range);
if (waitqueue_active(&ctx->fault_wqh))
__wake_up(&ctx->fault_wqh, TASK_NORMAL, 1, range);
spin_unlock_irq(&ctx->fault_pending_wqh.lock);
}
static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
struct userfaultfd_wake_range *range)
{
unsigned seq;
bool need_wakeup;
/*
* To be sure waitqueue_active() is not reordered by the CPU
* before the pagetable update, use an explicit SMP memory
* barrier here. PT lock release or mmap_read_unlock(mm) still
* have release semantics that can allow the
* waitqueue_active() to be reordered before the pte update.
*/
smp_mb();
/*
* Use waitqueue_active because it's very frequent to
* change the address space atomically even if there are no
* userfaults yet. So we take the spinlock only when we're
* sure we've userfaults to wake.
*/
do {
seq = read_seqcount_begin(&ctx->refile_seq);
need_wakeup = waitqueue_active(&ctx->fault_pending_wqh) ||
waitqueue_active(&ctx->fault_wqh);
cond_resched();
} while (read_seqcount_retry(&ctx->refile_seq, seq));
if (need_wakeup)
__wake_userfault(ctx, range);
}
static __always_inline int validate_unaligned_range(
struct mm_struct *mm, __u64 start, __u64 len)
{
__u64 task_size = mm->task_size;
if (len & ~PAGE_MASK)
return -EINVAL;
if (!len)
return -EINVAL;
if (start < mmap_min_addr)
return -EINVAL;
if (start >= task_size)
return -EINVAL;
if (len > task_size - start)
return -EINVAL;
if (start + len <= start)
return -EINVAL;
return 0;
}
static __always_inline int validate_range(struct mm_struct *mm,
__u64 start, __u64 len)
{
if (start & ~PAGE_MASK)
return -EINVAL;
return validate_unaligned_range(mm, start, len);
}
static int userfaultfd_register(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
struct mm_struct *mm = ctx->mm;
struct vm_area_struct *vma, *prev, *cur;
int ret;
struct uffdio_register uffdio_register;
struct uffdio_register __user *user_uffdio_register;
unsigned long vm_flags, new_flags;
bool found;
bool basic_ioctls;
unsigned long start, end, vma_end;
struct vma_iterator vmi;
pgoff_t pgoff;
user_uffdio_register = (struct uffdio_register __user *) arg;
ret = -EFAULT;
if (copy_from_user(&uffdio_register, user_uffdio_register,
sizeof(uffdio_register)-sizeof(__u64)))
goto out;
ret = -EINVAL;
if (!uffdio_register.mode)
goto out;
if (uffdio_register.mode & ~UFFD_API_REGISTER_MODES)
goto out;
vm_flags = 0;
if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MISSING)
vm_flags |= VM_UFFD_MISSING;
if (uffdio_register.mode & UFFDIO_REGISTER_MODE_WP) {
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
goto out;
#endif
vm_flags |= VM_UFFD_WP;
}
if (uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR) {
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
goto out;
#endif
vm_flags |= VM_UFFD_MINOR;
}
ret = validate_range(mm, uffdio_register.range.start,
uffdio_register.range.len);
if (ret)
goto out;
start = uffdio_register.range.start;
end = start + uffdio_register.range.len;
ret = -ENOMEM;
if (!mmget_not_zero(mm))
goto out;
ret = -EINVAL;
mmap_write_lock(mm);
vma_iter_init(&vmi, mm, start);
vma = vma_find(&vmi, end);
if (!vma)
goto out_unlock;
/*
* If the first vma contains huge pages, make sure start address
* is aligned to huge page size.
*/
if (is_vm_hugetlb_page(vma)) {
unsigned long vma_hpagesize = vma_kernel_pagesize(vma);
if (start & (vma_hpagesize - 1))
goto out_unlock;
}
/*
* Search for not compatible vmas.
*/
found = false;
basic_ioctls = false;
cur = vma;
do {
cond_resched();
BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^
!!(cur->vm_flags & __VM_UFFD_FLAGS));
/* check not compatible vmas */
ret = -EINVAL;
if (!vma_can_userfault(cur, vm_flags))
goto out_unlock;
/*
* UFFDIO_COPY will fill file holes even without
* PROT_WRITE. This check enforces that if this is a
* MAP_SHARED, the process has write permission to the backing
* file. If VM_MAYWRITE is set it also enforces that on a
* MAP_SHARED vma: there is no F_WRITE_SEAL and no further
* F_WRITE_SEAL can be taken until the vma is destroyed.
*/
ret = -EPERM;
if (unlikely(!(cur->vm_flags & VM_MAYWRITE)))
goto out_unlock;
/*
* If this vma contains ending address, and huge pages
* check alignment.
*/
if (is_vm_hugetlb_page(cur) && end <= cur->vm_end &&
end > cur->vm_start) {
unsigned long vma_hpagesize = vma_kernel_pagesize(cur);
ret = -EINVAL;
if (end & (vma_hpagesize - 1))
goto out_unlock;
}
if ((vm_flags & VM_UFFD_WP) && !(cur->vm_flags & VM_MAYWRITE))
goto out_unlock;
/*
* Check that this vma isn't already owned by a
* different userfaultfd. We can't allow more than one
* userfaultfd to own a single vma simultaneously or we
* wouldn't know which one to deliver the userfaults to.
*/
ret = -EBUSY;
if (cur->vm_userfaultfd_ctx.ctx &&
cur->vm_userfaultfd_ctx.ctx != ctx)
goto out_unlock;
/*
* Note vmas containing huge pages
*/
if (is_vm_hugetlb_page(cur))
basic_ioctls = true;
found = true;
} for_each_vma_range(vmi, cur, end);
BUG_ON(!found);
vma_iter_set(&vmi, start);
prev = vma_prev(&vmi);
if (vma->vm_start < start)
prev = vma;
ret = 0;
for_each_vma_range(vmi, vma, end) {
cond_resched();
BUG_ON(!vma_can_userfault(vma, vm_flags));
BUG_ON(vma->vm_userfaultfd_ctx.ctx &&
vma->vm_userfaultfd_ctx.ctx != ctx);
WARN_ON(!(vma->vm_flags & VM_MAYWRITE));
/*
* Nothing to do: this vma is already registered into this
* userfaultfd and with the right tracking mode too.
*/
if (vma->vm_userfaultfd_ctx.ctx == ctx &&
(vma->vm_flags & vm_flags) == vm_flags)
goto skip;
if (vma->vm_start > start)
start = vma->vm_start;
vma_end = min(end, vma->vm_end);
new_flags = (vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags;
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
vma->anon_vma, vma->vm_file, pgoff,
vma_policy(vma),
((struct vm_userfaultfd_ctx){ ctx }),
anon_vma_name(vma));
if (prev) {
/* vma_merge() invalidated the mas */
vma = prev;
goto next;
}
if (vma->vm_start < start) {
ret = split_vma(&vmi, vma, start, 1);
if (ret)
break;
}
if (vma->vm_end > end) {
ret = split_vma(&vmi, vma, end, 0);
if (ret)
break;
}
next:
/*
* In the vma_merge() successful mprotect-like case 8:
* the next vma was merged into the current one and
* the current one has not been updated yet.
*/
vma_start_write(vma);
userfaultfd_set_vm_flags(vma, new_flags);
vma->vm_userfaultfd_ctx.ctx = ctx;
if (is_vm_hugetlb_page(vma) && uffd_disable_huge_pmd_share(vma))
hugetlb_unshare_all_pmds(vma);
skip:
prev = vma;
start = vma->vm_end;
}
out_unlock:
mmap_write_unlock(mm);
mmput(mm);
if (!ret) {
__u64 ioctls_out;
ioctls_out = basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :
UFFD_API_RANGE_IOCTLS;
/*
* Declare the WP ioctl only if the WP mode is
* specified and all checks passed with the range
*/
if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_WP))
ioctls_out &= ~((__u64)1 << _UFFDIO_WRITEPROTECT);
/* CONTINUE ioctl is only supported for MINOR ranges. */
if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_MINOR))
ioctls_out &= ~((__u64)1 << _UFFDIO_CONTINUE);
/*
* Now that we scanned all vmas we can already tell
* userland which ioctls methods are guaranteed to
* succeed on this range.
*/
if (put_user(ioctls_out, &user_uffdio_register->ioctls))
ret = -EFAULT;
}
out:
return ret;
}
static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
struct mm_struct *mm = ctx->mm;
struct vm_area_struct *vma, *prev, *cur;
int ret;
struct uffdio_range uffdio_unregister;
unsigned long new_flags;
bool found;
unsigned long start, end, vma_end;
const void __user *buf = (void __user *)arg;
struct vma_iterator vmi;
pgoff_t pgoff;
ret = -EFAULT;
if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister)))
goto out;
ret = validate_range(mm, uffdio_unregister.start,
uffdio_unregister.len);
if (ret)
goto out;
start = uffdio_unregister.start;
end = start + uffdio_unregister.len;
ret = -ENOMEM;
if (!mmget_not_zero(mm))
goto out;
mmap_write_lock(mm);
ret = -EINVAL;
vma_iter_init(&vmi, mm, start);
vma = vma_find(&vmi, end);
if (!vma)
goto out_unlock;
/*
* If the first vma contains huge pages, make sure start address
* is aligned to huge page size.
*/
if (is_vm_hugetlb_page(vma)) {
unsigned long vma_hpagesize = vma_kernel_pagesize(vma);
if (start & (vma_hpagesize - 1))
goto out_unlock;
}
/*
* Search for not compatible vmas.
*/
found = false;
cur = vma;
do {
cond_resched();
BUG_ON(!!cur->vm_userfaultfd_ctx.ctx ^
!!(cur->vm_flags & __VM_UFFD_FLAGS));
/*
* Check not compatible vmas, not strictly required
* here as not compatible vmas cannot have an
* userfaultfd_ctx registered on them, but this
* provides for more strict behavior to notice
* unregistration errors.
*/
if (!vma_can_userfault(cur, cur->vm_flags))
goto out_unlock;
found = true;
} for_each_vma_range(vmi, cur, end);
BUG_ON(!found);
vma_iter_set(&vmi, start);
prev = vma_prev(&vmi);
if (vma->vm_start < start)
prev = vma;
ret = 0;
for_each_vma_range(vmi, vma, end) {
cond_resched();
BUG_ON(!vma_can_userfault(vma, vma->vm_flags));
/*
* Nothing to do: this vma is already registered into this
* userfaultfd and with the right tracking mode too.
*/
if (!vma->vm_userfaultfd_ctx.ctx)
goto skip;
WARN_ON(!(vma->vm_flags & VM_MAYWRITE));
if (vma->vm_start > start)
start = vma->vm_start;
vma_end = min(end, vma->vm_end);
if (userfaultfd_missing(vma)) {
/*
* Wake any concurrent pending userfault while
* we unregister, so they will not hang
* permanently and it avoids userland to call
* UFFDIO_WAKE explicitly.
*/
struct userfaultfd_wake_range range;
range.start = start;
range.len = vma_end - start;
wake_userfault(vma->vm_userfaultfd_ctx.ctx, &range);
}
/* Reset ptes for the whole vma range if wr-protected */
if (userfaultfd_wp(vma))
uffd_wp_range(vma, start, vma_end - start, false);
new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
vma->anon_vma, vma->vm_file, pgoff,
vma_policy(vma),
NULL_VM_UFFD_CTX, anon_vma_name(vma));
if (prev) {
vma = prev;
goto next;
}
if (vma->vm_start < start) {
ret = split_vma(&vmi, vma, start, 1);
if (ret)
break;
}
if (vma->vm_end > end) {
ret = split_vma(&vmi, vma, end, 0);
if (ret)
break;
}
next:
/*
* In the vma_merge() successful mprotect-like case 8:
* the next vma was merged into the current one and
* the current one has not been updated yet.
*/
vma_start_write(vma);
userfaultfd_set_vm_flags(vma, new_flags);
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
skip:
prev = vma;
start = vma->vm_end;
}
out_unlock:
mmap_write_unlock(mm);
mmput(mm);
out:
return ret;
}
/*
* userfaultfd_wake may be used in combination with the
* UFFDIO_*_MODE_DONTWAKE to wakeup userfaults in batches.
*/
static int userfaultfd_wake(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
int ret;
struct uffdio_range uffdio_wake;
struct userfaultfd_wake_range range;
const void __user *buf = (void __user *)arg;
ret = -EFAULT;
if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake)))
goto out;
ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len);
if (ret)
goto out;
range.start = uffdio_wake.start;
range.len = uffdio_wake.len;
/*
* len == 0 means wake all and we don't want to wake all here,
* so check it again to be sure.
*/
VM_BUG_ON(!range.len);
wake_userfault(ctx, &range);
ret = 0;
out:
return ret;
}
static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
__s64 ret;
struct uffdio_copy uffdio_copy;
struct uffdio_copy __user *user_uffdio_copy;
struct userfaultfd_wake_range range;
uffd_flags_t flags = 0;
user_uffdio_copy = (struct uffdio_copy __user *) arg;
ret = -EAGAIN;
if (atomic_read(&ctx->mmap_changing))
goto out;
ret = -EFAULT;
if (copy_from_user(&uffdio_copy, user_uffdio_copy,
/* don't copy "copy" last field */
sizeof(uffdio_copy)-sizeof(__s64)))
goto out;
ret = validate_unaligned_range(ctx->mm, uffdio_copy.src,
uffdio_copy.len);
if (ret)
goto out;
ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len);
if (ret)
goto out;
ret = -EINVAL;
if (uffdio_copy.mode & ~(UFFDIO_COPY_MODE_DONTWAKE|UFFDIO_COPY_MODE_WP))
goto out;
if (uffdio_copy.mode & UFFDIO_COPY_MODE_WP)
flags |= MFILL_ATOMIC_WP;
if (mmget_not_zero(ctx->mm)) {
ret = mfill_atomic_copy(ctx->mm, uffdio_copy.dst, uffdio_copy.src,
uffdio_copy.len, &ctx->mmap_changing,
flags);
mmput(ctx->mm);
} else {
return -ESRCH;
}
if (unlikely(put_user(ret, &user_uffdio_copy->copy)))
return -EFAULT;
if (ret < 0)
goto out;
BUG_ON(!ret);
/* len == 0 would wake all */
range.len = ret;
if (!(uffdio_copy.mode & UFFDIO_COPY_MODE_DONTWAKE)) {
range.start = uffdio_copy.dst;
wake_userfault(ctx, &range);
}
ret = range.len == uffdio_copy.len ? 0 : -EAGAIN;
out:
return ret;
}
static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
__s64 ret;
struct uffdio_zeropage uffdio_zeropage;
struct uffdio_zeropage __user *user_uffdio_zeropage;
struct userfaultfd_wake_range range;
user_uffdio_zeropage = (struct uffdio_zeropage __user *) arg;
ret = -EAGAIN;
if (atomic_read(&ctx->mmap_changing))
goto out;
ret = -EFAULT;
if (copy_from_user(&uffdio_zeropage, user_uffdio_zeropage,
/* don't copy "zeropage" last field */
sizeof(uffdio_zeropage)-sizeof(__s64)))
goto out;
ret = validate_range(ctx->mm, uffdio_zeropage.range.start,
uffdio_zeropage.range.len);
if (ret)
goto out;
ret = -EINVAL;
if (uffdio_zeropage.mode & ~UFFDIO_ZEROPAGE_MODE_DONTWAKE)
goto out;
if (mmget_not_zero(ctx->mm)) {
ret = mfill_atomic_zeropage(ctx->mm, uffdio_zeropage.range.start,
uffdio_zeropage.range.len,
&ctx->mmap_changing);
mmput(ctx->mm);
} else {
return -ESRCH;
}
if (unlikely(put_user(ret, &user_uffdio_zeropage->zeropage)))
return -EFAULT;
if (ret < 0)
goto out;
/* len == 0 would wake all */
BUG_ON(!ret);
range.len = ret;
if (!(uffdio_zeropage.mode & UFFDIO_ZEROPAGE_MODE_DONTWAKE)) {
range.start = uffdio_zeropage.range.start;
wake_userfault(ctx, &range);
}
ret = range.len == uffdio_zeropage.range.len ? 0 : -EAGAIN;
out:
return ret;
}
static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
int ret;
struct uffdio_writeprotect uffdio_wp;
struct uffdio_writeprotect __user *user_uffdio_wp;
struct userfaultfd_wake_range range;
bool mode_wp, mode_dontwake;
if (atomic_read(&ctx->mmap_changing))
return -EAGAIN;
user_uffdio_wp = (struct uffdio_writeprotect __user *) arg;
if (copy_from_user(&uffdio_wp, user_uffdio_wp,
sizeof(struct uffdio_writeprotect)))
return -EFAULT;
ret = validate_range(ctx->mm, uffdio_wp.range.start,
uffdio_wp.range.len);
if (ret)
return ret;
if (uffdio_wp.mode & ~(UFFDIO_WRITEPROTECT_MODE_DONTWAKE |
UFFDIO_WRITEPROTECT_MODE_WP))
return -EINVAL;
mode_wp = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP;
mode_dontwake = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE;
if (mode_wp && mode_dontwake)
return -EINVAL;
if (mmget_not_zero(ctx->mm)) {
ret = mwriteprotect_range(ctx->mm, uffdio_wp.range.start,
uffdio_wp.range.len, mode_wp,
&ctx->mmap_changing);
mmput(ctx->mm);
} else {
return -ESRCH;
}
if (ret)
return ret;
if (!mode_wp && !mode_dontwake) {
range.start = uffdio_wp.range.start;
range.len = uffdio_wp.range.len;
wake_userfault(ctx, &range);
}
return ret;
}
static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg)
{
__s64 ret;
struct uffdio_continue uffdio_continue;
struct uffdio_continue __user *user_uffdio_continue;
struct userfaultfd_wake_range range;
uffd_flags_t flags = 0;
user_uffdio_continue = (struct uffdio_continue __user *)arg;
ret = -EAGAIN;
if (atomic_read(&ctx->mmap_changing))
goto out;
ret = -EFAULT;
if (copy_from_user(&uffdio_continue, user_uffdio_continue,
/* don't copy the output fields */
sizeof(uffdio_continue) - (sizeof(__s64))))
goto out;
ret = validate_range(ctx->mm, uffdio_continue.range.start,
uffdio_continue.range.len);
if (ret)
goto out;
ret = -EINVAL;
if (uffdio_continue.mode & ~(UFFDIO_CONTINUE_MODE_DONTWAKE |
UFFDIO_CONTINUE_MODE_WP))
goto out;
if (uffdio_continue.mode & UFFDIO_CONTINUE_MODE_WP)
flags |= MFILL_ATOMIC_WP;
if (mmget_not_zero(ctx->mm)) {
ret = mfill_atomic_continue(ctx->mm, uffdio_continue.range.start,
uffdio_continue.range.len,
&ctx->mmap_changing, flags);
mmput(ctx->mm);
} else {
return -ESRCH;
}
if (unlikely(put_user(ret, &user_uffdio_continue->mapped)))
return -EFAULT;
if (ret < 0)
goto out;
/* len == 0 would wake all */
BUG_ON(!ret);
range.len = ret;
if (!(uffdio_continue.mode & UFFDIO_CONTINUE_MODE_DONTWAKE)) {
range.start = uffdio_continue.range.start;
wake_userfault(ctx, &range);
}
ret = range.len == uffdio_continue.range.len ? 0 : -EAGAIN;
out:
return ret;
}
static inline int userfaultfd_poison(struct userfaultfd_ctx *ctx, unsigned long arg)
{
__s64 ret;
struct uffdio_poison uffdio_poison;
struct uffdio_poison __user *user_uffdio_poison;
struct userfaultfd_wake_range range;
user_uffdio_poison = (struct uffdio_poison __user *)arg;
ret = -EAGAIN;
if (atomic_read(&ctx->mmap_changing))
goto out;
ret = -EFAULT;
if (copy_from_user(&uffdio_poison, user_uffdio_poison,
/* don't copy the output fields */
sizeof(uffdio_poison) - (sizeof(__s64))))
goto out;
ret = validate_range(ctx->mm, uffdio_poison.range.start,
uffdio_poison.range.len);
if (ret)
goto out;
ret = -EINVAL;
if (uffdio_poison.mode & ~UFFDIO_POISON_MODE_DONTWAKE)
goto out;
if (mmget_not_zero(ctx->mm)) {
ret = mfill_atomic_poison(ctx->mm, uffdio_poison.range.start,
uffdio_poison.range.len,
&ctx->mmap_changing, 0);
mmput(ctx->mm);
} else {
return -ESRCH;
}
if (unlikely(put_user(ret, &user_uffdio_poison->updated)))
return -EFAULT;
if (ret < 0)
goto out;
/* len == 0 would wake all */
BUG_ON(!ret);
range.len = ret;
if (!(uffdio_poison.mode & UFFDIO_POISON_MODE_DONTWAKE)) {
range.start = uffdio_poison.range.start;
wake_userfault(ctx, &range);
}
ret = range.len == uffdio_poison.range.len ? 0 : -EAGAIN;
out:
return ret;
}
static inline unsigned int uffd_ctx_features(__u64 user_features)
{
/*
* For the current set of features the bits just coincide. Set
* UFFD_FEATURE_INITIALIZED to mark the features as enabled.
*/
return (unsigned int)user_features | UFFD_FEATURE_INITIALIZED;
}
/*
* userland asks for a certain API version and we return which bits
* and ioctl commands are implemented in this kernel for such API
* version or -EINVAL if unknown.
*/
static int userfaultfd_api(struct userfaultfd_ctx *ctx,
unsigned long arg)
{
struct uffdio_api uffdio_api;
void __user *buf = (void __user *)arg;
unsigned int ctx_features;
int ret;
__u64 features;
ret = -EFAULT;
if (copy_from_user(&uffdio_api, buf, sizeof(uffdio_api)))
goto out;
features = uffdio_api.features;
ret = -EINVAL;
if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES))
goto err_out;
ret = -EPERM;
if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE))
goto err_out;
/* report all available features and ioctls to userland */
uffdio_api.features = UFFD_API_FEATURES;
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
uffdio_api.features &=
~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM);
#endif
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_WP
uffdio_api.features &= ~UFFD_FEATURE_PAGEFAULT_FLAG_WP;
#endif
#ifndef CONFIG_PTE_MARKER_UFFD_WP
uffdio_api.features &= ~UFFD_FEATURE_WP_HUGETLBFS_SHMEM;
uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED;
#endif
uffdio_api.ioctls = UFFD_API_IOCTLS;
ret = -EFAULT;
if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))
goto out;
/* only enable the requested features for this uffd context */
ctx_features = uffd_ctx_features(features);
ret = -EINVAL;
if (cmpxchg(&ctx->features, 0, ctx_features) != 0)
goto err_out;
ret = 0;
out:
return ret;
err_out:
memset(&uffdio_api, 0, sizeof(uffdio_api));
if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))
ret = -EFAULT;
goto out;
}
static long userfaultfd_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
{
int ret = -EINVAL;
struct userfaultfd_ctx *ctx = file->private_data;
if (cmd != UFFDIO_API && !userfaultfd_is_initialized(ctx))
return -EINVAL;
switch(cmd) {
case UFFDIO_API:
ret = userfaultfd_api(ctx, arg);
break;
case UFFDIO_REGISTER:
ret = userfaultfd_register(ctx, arg);
break;
case UFFDIO_UNREGISTER:
ret = userfaultfd_unregister(ctx, arg);
break;
case UFFDIO_WAKE:
ret = userfaultfd_wake(ctx, arg);
break;
case UFFDIO_COPY:
ret = userfaultfd_copy(ctx, arg);
break;
case UFFDIO_ZEROPAGE:
ret = userfaultfd_zeropage(ctx, arg);
break;
case UFFDIO_WRITEPROTECT:
ret = userfaultfd_writeprotect(ctx, arg);
break;
case UFFDIO_CONTINUE:
ret = userfaultfd_continue(ctx, arg);
break;
case UFFDIO_POISON:
ret = userfaultfd_poison(ctx, arg);
break;
}
return ret;
}
#ifdef CONFIG_PROC_FS
static void userfaultfd_show_fdinfo(struct seq_file *m, struct file *f)
{
struct userfaultfd_ctx *ctx = f->private_data;
wait_queue_entry_t *wq;
unsigned long pending = 0, total = 0;
spin_lock_irq(&ctx->fault_pending_wqh.lock);
list_for_each_entry(wq, &ctx->fault_pending_wqh.head, entry) {
pending++;
total++;
}
list_for_each_entry(wq, &ctx->fault_wqh.head, entry) {
total++;
}
spin_unlock_irq(&ctx->fault_pending_wqh.lock);
/*
* If more protocols will be added, there will be all shown
* separated by a space. Like this:
* protocols: aa:... bb:...
*/
seq_printf(m, "pending:\t%lu\ntotal:\t%lu\nAPI:\t%Lx:%x:%Lx\n",
pending, total, UFFD_API, ctx->features,
UFFD_API_IOCTLS|UFFD_API_RANGE_IOCTLS);
}
#endif
static const struct file_operations userfaultfd_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = userfaultfd_show_fdinfo,
#endif
.release = userfaultfd_release,
.poll = userfaultfd_poll,
.read = userfaultfd_read,
.unlocked_ioctl = userfaultfd_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.llseek = noop_llseek,
};
static void init_once_userfaultfd_ctx(void *mem)
{
struct userfaultfd_ctx *ctx = (struct userfaultfd_ctx *) mem;
init_waitqueue_head(&ctx->fault_pending_wqh);
init_waitqueue_head(&ctx->fault_wqh);
init_waitqueue_head(&ctx->event_wqh);
init_waitqueue_head(&ctx->fd_wqh);
seqcount_spinlock_init(&ctx->refile_seq, &ctx->fault_pending_wqh.lock);
}
static int new_userfaultfd(int flags)
{
struct userfaultfd_ctx *ctx;
int fd;
BUG_ON(!current->mm);
/* Check the UFFD_* constants for consistency. */
BUILD_BUG_ON(UFFD_USER_MODE_ONLY & UFFD_SHARED_FCNTL_FLAGS);
BUILD_BUG_ON(UFFD_CLOEXEC != O_CLOEXEC);
BUILD_BUG_ON(UFFD_NONBLOCK != O_NONBLOCK);
if (flags & ~(UFFD_SHARED_FCNTL_FLAGS | UFFD_USER_MODE_ONLY))
return -EINVAL;
ctx = kmem_cache_alloc(userfaultfd_ctx_cachep, GFP_KERNEL);
if (!ctx)
return -ENOMEM;
refcount_set(&ctx->refcount, 1);
ctx->flags = flags;
ctx->features = 0;
ctx->released = false;
atomic_set(&ctx->mmap_changing, 0);
ctx->mm = current->mm;
/* prevent the mm struct to be freed */
mmgrab(ctx->mm);
fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, ctx,
O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL);
if (fd < 0) {
mmdrop(ctx->mm);
kmem_cache_free(userfaultfd_ctx_cachep, ctx);
}
return fd;
}
static inline bool userfaultfd_syscall_allowed(int flags)
{
/* Userspace-only page faults are always allowed */
if (flags & UFFD_USER_MODE_ONLY)
return true;
/*
* The user is requesting a userfaultfd which can handle kernel faults.
* Privileged users are always allowed to do this.
*/
if (capable(CAP_SYS_PTRACE))
return true;
/* Otherwise, access to kernel fault handling is sysctl controlled. */
return sysctl_unprivileged_userfaultfd;
}
SYSCALL_DEFINE1(userfaultfd, int, flags)
{
if (!userfaultfd_syscall_allowed(flags))
return -EPERM;
return new_userfaultfd(flags);
}
static long userfaultfd_dev_ioctl(struct file *file, unsigned int cmd, unsigned long flags)
{
if (cmd != USERFAULTFD_IOC_NEW)
return -EINVAL;
return new_userfaultfd(flags);
}
static const struct file_operations userfaultfd_dev_fops = {
.unlocked_ioctl = userfaultfd_dev_ioctl,
.compat_ioctl = userfaultfd_dev_ioctl,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
static struct miscdevice userfaultfd_misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = "userfaultfd",
.fops = &userfaultfd_dev_fops
};
static int __init userfaultfd_init(void)
{
int ret;
ret = misc_register(&userfaultfd_misc);
if (ret)
return ret;
userfaultfd_ctx_cachep = kmem_cache_create("userfaultfd_ctx_cache",
sizeof(struct userfaultfd_ctx),
0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC,
init_once_userfaultfd_ctx);
#ifdef CONFIG_SYSCTL
register_sysctl_init("vm", vm_userfaultfd_table);
#endif
return 0;
}
__initcall(userfaultfd_init);
| linux-master | fs/userfaultfd.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* binfmt_misc.c
*
* Copyright (C) 1997 Richard Günther
*
* binfmt_misc detects binaries via a magic or filename extension and invokes
* a specified wrapper. See Documentation/admin-guide/binfmt-misc.rst for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched/mm.h>
#include <linux/magic.h>
#include <linux/binfmts.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/string_helpers.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/fs_context.h>
#include <linux/syscalls.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include "internal.h"
#ifdef DEBUG
# define USE_DEBUG 1
#else
# define USE_DEBUG 0
#endif
enum {
VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
};
static LIST_HEAD(entries);
static int enabled = 1;
enum {Enabled, Magic};
#define MISC_FMT_PRESERVE_ARGV0 (1UL << 31)
#define MISC_FMT_OPEN_BINARY (1UL << 30)
#define MISC_FMT_CREDENTIALS (1UL << 29)
#define MISC_FMT_OPEN_FILE (1UL << 28)
typedef struct {
struct list_head list;
unsigned long flags; /* type, status, etc. */
int offset; /* offset of magic */
int size; /* size of magic/mask */
char *magic; /* magic or filename extension */
char *mask; /* mask, NULL for exact match */
const char *interpreter; /* filename of interpreter */
char *name;
struct dentry *dentry;
struct file *interp_file;
} Node;
static DEFINE_RWLOCK(entries_lock);
static struct file_system_type bm_fs_type;
static struct vfsmount *bm_mnt;
static int entry_count;
/*
* Max length of the register string. Determined by:
* - 7 delimiters
* - name: ~50 bytes
* - type: 1 byte
* - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE)
* - magic: 128 bytes (512 in escaped form)
* - mask: 128 bytes (512 in escaped form)
* - interp: ~50 bytes
* - flags: 5 bytes
* Round that up a bit, and then back off to hold the internal data
* (like struct Node).
*/
#define MAX_REGISTER_LENGTH 1920
/*
* Check if we support the binfmt
* if we do, return the node, else NULL
* locking is done in load_misc_binary
*/
static Node *check_file(struct linux_binprm *bprm)
{
char *p = strrchr(bprm->interp, '.');
struct list_head *l;
/* Walk all the registered handlers. */
list_for_each(l, &entries) {
Node *e = list_entry(l, Node, list);
char *s;
int j;
/* Make sure this one is currently enabled. */
if (!test_bit(Enabled, &e->flags))
continue;
/* Do matching based on extension if applicable. */
if (!test_bit(Magic, &e->flags)) {
if (p && !strcmp(e->magic, p + 1))
return e;
continue;
}
/* Do matching based on magic & mask. */
s = bprm->buf + e->offset;
if (e->mask) {
for (j = 0; j < e->size; j++)
if ((*s++ ^ e->magic[j]) & e->mask[j])
break;
} else {
for (j = 0; j < e->size; j++)
if ((*s++ ^ e->magic[j]))
break;
}
if (j == e->size)
return e;
}
return NULL;
}
/*
* the loader itself
*/
static int load_misc_binary(struct linux_binprm *bprm)
{
Node *fmt;
struct file *interp_file = NULL;
int retval;
retval = -ENOEXEC;
if (!enabled)
return retval;
/* to keep locking time low, we copy the interpreter string */
read_lock(&entries_lock);
fmt = check_file(bprm);
if (fmt)
dget(fmt->dentry);
read_unlock(&entries_lock);
if (!fmt)
return retval;
/* Need to be able to load the file after exec */
retval = -ENOENT;
if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
goto ret;
if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) {
bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0;
} else {
retval = remove_arg_zero(bprm);
if (retval)
goto ret;
}
if (fmt->flags & MISC_FMT_OPEN_BINARY)
bprm->have_execfd = 1;
/* make argv[1] be the path to the binary */
retval = copy_string_kernel(bprm->interp, bprm);
if (retval < 0)
goto ret;
bprm->argc++;
/* add the interp as argv[0] */
retval = copy_string_kernel(fmt->interpreter, bprm);
if (retval < 0)
goto ret;
bprm->argc++;
/* Update interp in case binfmt_script needs it. */
retval = bprm_change_interp(fmt->interpreter, bprm);
if (retval < 0)
goto ret;
if (fmt->flags & MISC_FMT_OPEN_FILE) {
interp_file = file_clone_open(fmt->interp_file);
if (!IS_ERR(interp_file))
deny_write_access(interp_file);
} else {
interp_file = open_exec(fmt->interpreter);
}
retval = PTR_ERR(interp_file);
if (IS_ERR(interp_file))
goto ret;
bprm->interpreter = interp_file;
if (fmt->flags & MISC_FMT_CREDENTIALS)
bprm->execfd_creds = 1;
retval = 0;
ret:
dput(fmt->dentry);
return retval;
}
/* Command parsers */
/*
* parses and copies one argument enclosed in del from *sp to *dp,
* recognising the \x special.
* returns pointer to the copied argument or NULL in case of an
* error (and sets err) or null argument length.
*/
static char *scanarg(char *s, char del)
{
char c;
while ((c = *s++) != del) {
if (c == '\\' && *s == 'x') {
s++;
if (!isxdigit(*s++))
return NULL;
if (!isxdigit(*s++))
return NULL;
}
}
s[-1] ='\0';
return s;
}
static char *check_special_flags(char *sfs, Node *e)
{
char *p = sfs;
int cont = 1;
/* special flags */
while (cont) {
switch (*p) {
case 'P':
pr_debug("register: flag: P (preserve argv0)\n");
p++;
e->flags |= MISC_FMT_PRESERVE_ARGV0;
break;
case 'O':
pr_debug("register: flag: O (open binary)\n");
p++;
e->flags |= MISC_FMT_OPEN_BINARY;
break;
case 'C':
pr_debug("register: flag: C (preserve creds)\n");
p++;
/* this flags also implies the
open-binary flag */
e->flags |= (MISC_FMT_CREDENTIALS |
MISC_FMT_OPEN_BINARY);
break;
case 'F':
pr_debug("register: flag: F: open interpreter file now\n");
p++;
e->flags |= MISC_FMT_OPEN_FILE;
break;
default:
cont = 0;
}
}
return p;
}
/*
* This registers a new binary format, it recognises the syntax
* ':name:type:offset:magic:mask:interpreter:flags'
* where the ':' is the IFS, that can be chosen with the first char
*/
static Node *create_entry(const char __user *buffer, size_t count)
{
Node *e;
int memsize, err;
char *buf, *p;
char del;
pr_debug("register: received %zu bytes\n", count);
/* some sanity checks */
err = -EINVAL;
if ((count < 11) || (count > MAX_REGISTER_LENGTH))
goto out;
err = -ENOMEM;
memsize = sizeof(Node) + count + 8;
e = kmalloc(memsize, GFP_KERNEL);
if (!e)
goto out;
p = buf = (char *)e + sizeof(Node);
memset(e, 0, sizeof(Node));
if (copy_from_user(buf, buffer, count))
goto efault;
del = *p++; /* delimeter */
pr_debug("register: delim: %#x {%c}\n", del, del);
/* Pad the buffer with the delim to simplify parsing below. */
memset(buf + count, del, 8);
/* Parse the 'name' field. */
e->name = p;
p = strchr(p, del);
if (!p)
goto einval;
*p++ = '\0';
if (!e->name[0] ||
!strcmp(e->name, ".") ||
!strcmp(e->name, "..") ||
strchr(e->name, '/'))
goto einval;
pr_debug("register: name: {%s}\n", e->name);
/* Parse the 'type' field. */
switch (*p++) {
case 'E':
pr_debug("register: type: E (extension)\n");
e->flags = 1 << Enabled;
break;
case 'M':
pr_debug("register: type: M (magic)\n");
e->flags = (1 << Enabled) | (1 << Magic);
break;
default:
goto einval;
}
if (*p++ != del)
goto einval;
if (test_bit(Magic, &e->flags)) {
/* Handle the 'M' (magic) format. */
char *s;
/* Parse the 'offset' field. */
s = strchr(p, del);
if (!s)
goto einval;
*s = '\0';
if (p != s) {
int r = kstrtoint(p, 10, &e->offset);
if (r != 0 || e->offset < 0)
goto einval;
}
p = s;
if (*p++)
goto einval;
pr_debug("register: offset: %#x\n", e->offset);
/* Parse the 'magic' field. */
e->magic = p;
p = scanarg(p, del);
if (!p)
goto einval;
if (!e->magic[0])
goto einval;
if (USE_DEBUG)
print_hex_dump_bytes(
KBUILD_MODNAME ": register: magic[raw]: ",
DUMP_PREFIX_NONE, e->magic, p - e->magic);
/* Parse the 'mask' field. */
e->mask = p;
p = scanarg(p, del);
if (!p)
goto einval;
if (!e->mask[0]) {
e->mask = NULL;
pr_debug("register: mask[raw]: none\n");
} else if (USE_DEBUG)
print_hex_dump_bytes(
KBUILD_MODNAME ": register: mask[raw]: ",
DUMP_PREFIX_NONE, e->mask, p - e->mask);
/*
* Decode the magic & mask fields.
* Note: while we might have accepted embedded NUL bytes from
* above, the unescape helpers here will stop at the first one
* it encounters.
*/
e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX);
if (e->mask &&
string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size)
goto einval;
if (e->size > BINPRM_BUF_SIZE ||
BINPRM_BUF_SIZE - e->size < e->offset)
goto einval;
pr_debug("register: magic/mask length: %i\n", e->size);
if (USE_DEBUG) {
print_hex_dump_bytes(
KBUILD_MODNAME ": register: magic[decoded]: ",
DUMP_PREFIX_NONE, e->magic, e->size);
if (e->mask) {
int i;
char *masked = kmalloc(e->size, GFP_KERNEL);
print_hex_dump_bytes(
KBUILD_MODNAME ": register: mask[decoded]: ",
DUMP_PREFIX_NONE, e->mask, e->size);
if (masked) {
for (i = 0; i < e->size; ++i)
masked[i] = e->magic[i] & e->mask[i];
print_hex_dump_bytes(
KBUILD_MODNAME ": register: magic[masked]: ",
DUMP_PREFIX_NONE, masked, e->size);
kfree(masked);
}
}
}
} else {
/* Handle the 'E' (extension) format. */
/* Skip the 'offset' field. */
p = strchr(p, del);
if (!p)
goto einval;
*p++ = '\0';
/* Parse the 'magic' field. */
e->magic = p;
p = strchr(p, del);
if (!p)
goto einval;
*p++ = '\0';
if (!e->magic[0] || strchr(e->magic, '/'))
goto einval;
pr_debug("register: extension: {%s}\n", e->magic);
/* Skip the 'mask' field. */
p = strchr(p, del);
if (!p)
goto einval;
*p++ = '\0';
}
/* Parse the 'interpreter' field. */
e->interpreter = p;
p = strchr(p, del);
if (!p)
goto einval;
*p++ = '\0';
if (!e->interpreter[0])
goto einval;
pr_debug("register: interpreter: {%s}\n", e->interpreter);
/* Parse the 'flags' field. */
p = check_special_flags(p, e);
if (*p == '\n')
p++;
if (p != buf + count)
goto einval;
return e;
out:
return ERR_PTR(err);
efault:
kfree(e);
return ERR_PTR(-EFAULT);
einval:
kfree(e);
return ERR_PTR(-EINVAL);
}
/*
* Set status of entry/binfmt_misc:
* '1' enables, '0' disables and '-1' clears entry/binfmt_misc
*/
static int parse_command(const char __user *buffer, size_t count)
{
char s[4];
if (count > 3)
return -EINVAL;
if (copy_from_user(s, buffer, count))
return -EFAULT;
if (!count)
return 0;
if (s[count - 1] == '\n')
count--;
if (count == 1 && s[0] == '0')
return 1;
if (count == 1 && s[0] == '1')
return 2;
if (count == 2 && s[0] == '-' && s[1] == '1')
return 3;
return -EINVAL;
}
/* generic stuff */
static void entry_status(Node *e, char *page)
{
char *dp = page;
const char *status = "disabled";
if (test_bit(Enabled, &e->flags))
status = "enabled";
if (!VERBOSE_STATUS) {
sprintf(page, "%s\n", status);
return;
}
dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter);
/* print the special flags */
dp += sprintf(dp, "flags: ");
if (e->flags & MISC_FMT_PRESERVE_ARGV0)
*dp++ = 'P';
if (e->flags & MISC_FMT_OPEN_BINARY)
*dp++ = 'O';
if (e->flags & MISC_FMT_CREDENTIALS)
*dp++ = 'C';
if (e->flags & MISC_FMT_OPEN_FILE)
*dp++ = 'F';
*dp++ = '\n';
if (!test_bit(Magic, &e->flags)) {
sprintf(dp, "extension .%s\n", e->magic);
} else {
dp += sprintf(dp, "offset %i\nmagic ", e->offset);
dp = bin2hex(dp, e->magic, e->size);
if (e->mask) {
dp += sprintf(dp, "\nmask ");
dp = bin2hex(dp, e->mask, e->size);
}
*dp++ = '\n';
*dp = '\0';
}
}
static struct inode *bm_get_inode(struct super_block *sb, int mode)
{
struct inode *inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
}
return inode;
}
static void bm_evict_inode(struct inode *inode)
{
Node *e = inode->i_private;
if (e && e->flags & MISC_FMT_OPEN_FILE)
filp_close(e->interp_file, NULL);
clear_inode(inode);
kfree(e);
}
static void kill_node(Node *e)
{
struct dentry *dentry;
write_lock(&entries_lock);
list_del_init(&e->list);
write_unlock(&entries_lock);
dentry = e->dentry;
drop_nlink(d_inode(dentry));
d_drop(dentry);
dput(dentry);
simple_release_fs(&bm_mnt, &entry_count);
}
/* /<entry> */
static ssize_t
bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
Node *e = file_inode(file)->i_private;
ssize_t res;
char *page;
page = (char *) __get_free_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
entry_status(e, page);
res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page));
free_page((unsigned long) page);
return res;
}
static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
struct dentry *root;
Node *e = file_inode(file)->i_private;
int res = parse_command(buffer, count);
switch (res) {
case 1:
/* Disable this handler. */
clear_bit(Enabled, &e->flags);
break;
case 2:
/* Enable this handler. */
set_bit(Enabled, &e->flags);
break;
case 3:
/* Delete this handler. */
root = file_inode(file)->i_sb->s_root;
inode_lock(d_inode(root));
if (!list_empty(&e->list))
kill_node(e);
inode_unlock(d_inode(root));
break;
default:
return res;
}
return count;
}
static const struct file_operations bm_entry_operations = {
.read = bm_entry_read,
.write = bm_entry_write,
.llseek = default_llseek,
};
/* /register */
static ssize_t bm_register_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
Node *e;
struct inode *inode;
struct super_block *sb = file_inode(file)->i_sb;
struct dentry *root = sb->s_root, *dentry;
int err = 0;
struct file *f = NULL;
e = create_entry(buffer, count);
if (IS_ERR(e))
return PTR_ERR(e);
if (e->flags & MISC_FMT_OPEN_FILE) {
f = open_exec(e->interpreter);
if (IS_ERR(f)) {
pr_notice("register: failed to install interpreter file %s\n",
e->interpreter);
kfree(e);
return PTR_ERR(f);
}
e->interp_file = f;
}
inode_lock(d_inode(root));
dentry = lookup_one_len(e->name, root, strlen(e->name));
err = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out;
err = -EEXIST;
if (d_really_is_positive(dentry))
goto out2;
inode = bm_get_inode(sb, S_IFREG | 0644);
err = -ENOMEM;
if (!inode)
goto out2;
err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count);
if (err) {
iput(inode);
inode = NULL;
goto out2;
}
e->dentry = dget(dentry);
inode->i_private = e;
inode->i_fop = &bm_entry_operations;
d_instantiate(dentry, inode);
write_lock(&entries_lock);
list_add(&e->list, &entries);
write_unlock(&entries_lock);
err = 0;
out2:
dput(dentry);
out:
inode_unlock(d_inode(root));
if (err) {
if (f)
filp_close(f, NULL);
kfree(e);
return err;
}
return count;
}
static const struct file_operations bm_register_operations = {
.write = bm_register_write,
.llseek = noop_llseek,
};
/* /status */
static ssize_t
bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
char *s = enabled ? "enabled\n" : "disabled\n";
return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
}
static ssize_t bm_status_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
int res = parse_command(buffer, count);
struct dentry *root;
switch (res) {
case 1:
/* Disable all handlers. */
enabled = 0;
break;
case 2:
/* Enable all handlers. */
enabled = 1;
break;
case 3:
/* Delete all handlers. */
root = file_inode(file)->i_sb->s_root;
inode_lock(d_inode(root));
while (!list_empty(&entries))
kill_node(list_first_entry(&entries, Node, list));
inode_unlock(d_inode(root));
break;
default:
return res;
}
return count;
}
static const struct file_operations bm_status_operations = {
.read = bm_status_read,
.write = bm_status_write,
.llseek = default_llseek,
};
/* Superblock handling */
static const struct super_operations s_ops = {
.statfs = simple_statfs,
.evict_inode = bm_evict_inode,
};
static int bm_fill_super(struct super_block *sb, struct fs_context *fc)
{
int err;
static const struct tree_descr bm_files[] = {
[2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
[3] = {"register", &bm_register_operations, S_IWUSR},
/* last one */ {""}
};
err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files);
if (!err)
sb->s_op = &s_ops;
return err;
}
static int bm_get_tree(struct fs_context *fc)
{
return get_tree_single(fc, bm_fill_super);
}
static const struct fs_context_operations bm_context_ops = {
.get_tree = bm_get_tree,
};
static int bm_init_fs_context(struct fs_context *fc)
{
fc->ops = &bm_context_ops;
return 0;
}
static struct linux_binfmt misc_format = {
.module = THIS_MODULE,
.load_binary = load_misc_binary,
};
static struct file_system_type bm_fs_type = {
.owner = THIS_MODULE,
.name = "binfmt_misc",
.init_fs_context = bm_init_fs_context,
.kill_sb = kill_litter_super,
};
MODULE_ALIAS_FS("binfmt_misc");
static int __init init_misc_binfmt(void)
{
int err = register_filesystem(&bm_fs_type);
if (!err)
insert_binfmt(&misc_format);
return err;
}
static void __exit exit_misc_binfmt(void)
{
unregister_binfmt(&misc_format);
unregister_filesystem(&bm_fs_type);
}
core_initcall(init_misc_binfmt);
module_exit(exit_misc_binfmt);
MODULE_LICENSE("GPL");
| linux-master | fs/binfmt_misc.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/read_write.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/sched/xacct.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/splice.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/fs.h>
#include "internal.h"
#include <linux/uaccess.h>
#include <asm/unistd.h>
const struct file_operations generic_ro_fops = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
.mmap = generic_file_readonly_mmap,
.splice_read = filemap_splice_read,
};
EXPORT_SYMBOL(generic_ro_fops);
static inline bool unsigned_offsets(struct file *file)
{
return file->f_mode & FMODE_UNSIGNED_OFFSET;
}
/**
* vfs_setpos - update the file offset for lseek
* @file: file structure in question
* @offset: file offset to seek to
* @maxsize: maximum file size
*
* This is a low-level filesystem helper for updating the file offset to
* the value specified by @offset if the given offset is valid and it is
* not equal to the current file offset.
*
* Return the specified offset on success and -EINVAL on invalid offset.
*/
loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
{
if (offset < 0 && !unsigned_offsets(file))
return -EINVAL;
if (offset > maxsize)
return -EINVAL;
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
return offset;
}
EXPORT_SYMBOL(vfs_setpos);
/**
* generic_file_llseek_size - generic llseek implementation for regular files
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
* @maxsize: max size of this file in file system
* @eof: offset used for SEEK_END position
*
* This is a variant of generic_file_llseek that allows passing in a custom
* maximum file size and a custom EOF position, for e.g. hashed directories
*
* Synchronization:
* SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
* SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
* read/writes behave like SEEK_SET against seeks.
*/
loff_t
generic_file_llseek_size(struct file *file, loff_t offset, int whence,
loff_t maxsize, loff_t eof)
{
switch (whence) {
case SEEK_END:
offset += eof;
break;
case SEEK_CUR:
/*
* Here we special-case the lseek(fd, 0, SEEK_CUR)
* position-querying operation. Avoid rewriting the "same"
* f_pos value back to the file because a concurrent read(),
* write() or lseek() might have altered it
*/
if (offset == 0)
return file->f_pos;
/*
* f_lock protects against read/modify/write race with other
* SEEK_CURs. Note that parallel writes and reads behave
* like SEEK_SET.
*/
spin_lock(&file->f_lock);
offset = vfs_setpos(file, file->f_pos + offset, maxsize);
spin_unlock(&file->f_lock);
return offset;
case SEEK_DATA:
/*
* In the generic case the entire file is data, so as long as
* offset isn't at the end of the file then the offset is data.
*/
if ((unsigned long long)offset >= eof)
return -ENXIO;
break;
case SEEK_HOLE:
/*
* There is a virtual hole at the end of the file, so as long as
* offset isn't i_size or larger, return i_size.
*/
if ((unsigned long long)offset >= eof)
return -ENXIO;
offset = eof;
break;
}
return vfs_setpos(file, offset, maxsize);
}
EXPORT_SYMBOL(generic_file_llseek_size);
/**
* generic_file_llseek - generic llseek implementation for regular files
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
*
* This is a generic implemenation of ->llseek useable for all normal local
* filesystems. It just updates the file offset to the value specified by
* @offset and @whence.
*/
loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
return generic_file_llseek_size(file, offset, whence,
inode->i_sb->s_maxbytes,
i_size_read(inode));
}
EXPORT_SYMBOL(generic_file_llseek);
/**
* fixed_size_llseek - llseek implementation for fixed-sized devices
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
* @size: size of the file
*
*/
loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
{
switch (whence) {
case SEEK_SET: case SEEK_CUR: case SEEK_END:
return generic_file_llseek_size(file, offset, whence,
size, size);
default:
return -EINVAL;
}
}
EXPORT_SYMBOL(fixed_size_llseek);
/**
* no_seek_end_llseek - llseek implementation for fixed-sized devices
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
*
*/
loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
{
switch (whence) {
case SEEK_SET: case SEEK_CUR:
return generic_file_llseek_size(file, offset, whence,
OFFSET_MAX, 0);
default:
return -EINVAL;
}
}
EXPORT_SYMBOL(no_seek_end_llseek);
/**
* no_seek_end_llseek_size - llseek implementation for fixed-sized devices
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
* @size: maximal offset allowed
*
*/
loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size)
{
switch (whence) {
case SEEK_SET: case SEEK_CUR:
return generic_file_llseek_size(file, offset, whence,
size, 0);
default:
return -EINVAL;
}
}
EXPORT_SYMBOL(no_seek_end_llseek_size);
/**
* noop_llseek - No Operation Performed llseek implementation
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
*
* This is an implementation of ->llseek useable for the rare special case when
* userspace expects the seek to succeed but the (device) file is actually not
* able to perform the seek. In this case you use noop_llseek() instead of
* falling back to the default implementation of ->llseek.
*/
loff_t noop_llseek(struct file *file, loff_t offset, int whence)
{
return file->f_pos;
}
EXPORT_SYMBOL(noop_llseek);
loff_t default_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file_inode(file);
loff_t retval;
inode_lock(inode);
switch (whence) {
case SEEK_END:
offset += i_size_read(inode);
break;
case SEEK_CUR:
if (offset == 0) {
retval = file->f_pos;
goto out;
}
offset += file->f_pos;
break;
case SEEK_DATA:
/*
* In the generic case the entire file is data, so as
* long as offset isn't at the end of the file then the
* offset is data.
*/
if (offset >= inode->i_size) {
retval = -ENXIO;
goto out;
}
break;
case SEEK_HOLE:
/*
* There is a virtual hole at the end of the file, so
* as long as offset isn't i_size or larger, return
* i_size.
*/
if (offset >= inode->i_size) {
retval = -ENXIO;
goto out;
}
offset = inode->i_size;
break;
}
retval = -EINVAL;
if (offset >= 0 || unsigned_offsets(file)) {
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
retval = offset;
}
out:
inode_unlock(inode);
return retval;
}
EXPORT_SYMBOL(default_llseek);
loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
{
if (!(file->f_mode & FMODE_LSEEK))
return -ESPIPE;
return file->f_op->llseek(file, offset, whence);
}
EXPORT_SYMBOL(vfs_llseek);
static off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence)
{
off_t retval;
struct fd f = fdget_pos(fd);
if (!f.file)
return -EBADF;
retval = -EINVAL;
if (whence <= SEEK_MAX) {
loff_t res = vfs_llseek(f.file, offset, whence);
retval = res;
if (res != (loff_t)retval)
retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
}
fdput_pos(f);
return retval;
}
SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
{
return ksys_lseek(fd, offset, whence);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
{
return ksys_lseek(fd, offset, whence);
}
#endif
#if !defined(CONFIG_64BIT) || defined(CONFIG_COMPAT) || \
defined(__ARCH_WANT_SYS_LLSEEK)
SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
unsigned long, offset_low, loff_t __user *, result,
unsigned int, whence)
{
int retval;
struct fd f = fdget_pos(fd);
loff_t offset;
if (!f.file)
return -EBADF;
retval = -EINVAL;
if (whence > SEEK_MAX)
goto out_putf;
offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low,
whence);
retval = (int)offset;
if (offset >= 0) {
retval = -EFAULT;
if (!copy_to_user(result, &offset, sizeof(offset)))
retval = 0;
}
out_putf:
fdput_pos(f);
return retval;
}
#endif
int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
{
if (unlikely((ssize_t) count < 0))
return -EINVAL;
if (ppos) {
loff_t pos = *ppos;
if (unlikely(pos < 0)) {
if (!unsigned_offsets(file))
return -EINVAL;
if (count >= -pos) /* both values are in 0..LLONG_MAX */
return -EOVERFLOW;
} else if (unlikely((loff_t) (pos + count) < 0)) {
if (!unsigned_offsets(file))
return -EINVAL;
}
}
return security_file_permission(file,
read_write == READ ? MAY_READ : MAY_WRITE);
}
EXPORT_SYMBOL(rw_verify_area);
static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
struct kiocb kiocb;
struct iov_iter iter;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
kiocb.ki_pos = (ppos ? *ppos : 0);
iov_iter_ubuf(&iter, ITER_DEST, buf, len);
ret = call_read_iter(filp, &kiocb, &iter);
BUG_ON(ret == -EIOCBQUEUED);
if (ppos)
*ppos = kiocb.ki_pos;
return ret;
}
static int warn_unsupported(struct file *file, const char *op)
{
pr_warn_ratelimited(
"kernel %s not supported for file %pD4 (pid: %d comm: %.20s)\n",
op, file, current->pid, current->comm);
return -EINVAL;
}
ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
struct kvec iov = {
.iov_base = buf,
.iov_len = min_t(size_t, count, MAX_RW_COUNT),
};
struct kiocb kiocb;
struct iov_iter iter;
ssize_t ret;
if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ)))
return -EINVAL;
if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
/*
* Also fail if ->read_iter and ->read are both wired up as that
* implies very convoluted semantics.
*/
if (unlikely(!file->f_op->read_iter || file->f_op->read))
return warn_unsupported(file, "read");
init_sync_kiocb(&kiocb, file);
kiocb.ki_pos = pos ? *pos : 0;
iov_iter_kvec(&iter, ITER_DEST, &iov, 1, iov.iov_len);
ret = file->f_op->read_iter(&kiocb, &iter);
if (ret > 0) {
if (pos)
*pos = kiocb.ki_pos;
fsnotify_access(file);
add_rchar(current, ret);
}
inc_syscr(current);
return ret;
}
ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
ssize_t ret;
ret = rw_verify_area(READ, file, pos, count);
if (ret)
return ret;
return __kernel_read(file, buf, count, pos);
}
EXPORT_SYMBOL(kernel_read);
ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
if (unlikely(!access_ok(buf, count)))
return -EFAULT;
ret = rw_verify_area(READ, file, pos, count);
if (ret)
return ret;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
if (file->f_op->read)
ret = file->f_op->read(file, buf, count, pos);
else if (file->f_op->read_iter)
ret = new_sync_read(file, buf, count, pos);
else
ret = -EINVAL;
if (ret > 0) {
fsnotify_access(file);
add_rchar(current, ret);
}
inc_syscr(current);
return ret;
}
static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
struct kiocb kiocb;
struct iov_iter iter;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
kiocb.ki_pos = (ppos ? *ppos : 0);
iov_iter_ubuf(&iter, ITER_SOURCE, (void __user *)buf, len);
ret = call_write_iter(filp, &kiocb, &iter);
BUG_ON(ret == -EIOCBQUEUED);
if (ret > 0 && ppos)
*ppos = kiocb.ki_pos;
return ret;
}
/* caller is responsible for file_start_write/file_end_write */
ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos)
{
struct kiocb kiocb;
ssize_t ret;
if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE)))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
/*
* Also fail if ->write_iter and ->write are both wired up as that
* implies very convoluted semantics.
*/
if (unlikely(!file->f_op->write_iter || file->f_op->write))
return warn_unsupported(file, "write");
init_sync_kiocb(&kiocb, file);
kiocb.ki_pos = pos ? *pos : 0;
ret = file->f_op->write_iter(&kiocb, from);
if (ret > 0) {
if (pos)
*pos = kiocb.ki_pos;
fsnotify_modify(file);
add_wchar(current, ret);
}
inc_syscw(current);
return ret;
}
/* caller is responsible for file_start_write/file_end_write */
ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)
{
struct kvec iov = {
.iov_base = (void *)buf,
.iov_len = min_t(size_t, count, MAX_RW_COUNT),
};
struct iov_iter iter;
iov_iter_kvec(&iter, ITER_SOURCE, &iov, 1, iov.iov_len);
return __kernel_write_iter(file, &iter, pos);
}
/*
* This "EXPORT_SYMBOL_GPL()" is more of a "EXPORT_SYMBOL_DONTUSE()",
* but autofs is one of the few internal kernel users that actually
* wants this _and_ can be built as a module. So we need to export
* this symbol for autofs, even though it really isn't appropriate
* for any other kernel modules.
*/
EXPORT_SYMBOL_GPL(__kernel_write);
ssize_t kernel_write(struct file *file, const void *buf, size_t count,
loff_t *pos)
{
ssize_t ret;
ret = rw_verify_area(WRITE, file, pos, count);
if (ret)
return ret;
file_start_write(file);
ret = __kernel_write(file, buf, count, pos);
file_end_write(file);
return ret;
}
EXPORT_SYMBOL(kernel_write);
ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
if (unlikely(!access_ok(buf, count)))
return -EFAULT;
ret = rw_verify_area(WRITE, file, pos, count);
if (ret)
return ret;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
file_start_write(file);
if (file->f_op->write)
ret = file->f_op->write(file, buf, count, pos);
else if (file->f_op->write_iter)
ret = new_sync_write(file, buf, count, pos);
else
ret = -EINVAL;
if (ret > 0) {
fsnotify_modify(file);
add_wchar(current, ret);
}
inc_syscw(current);
file_end_write(file);
return ret;
}
/* file_ppos returns &file->f_pos or NULL if file is stream */
static inline loff_t *file_ppos(struct file *file)
{
return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos;
}
ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_read(f.file, buf, count, ppos);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
return ret;
}
SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
{
return ksys_read(fd, buf, count);
}
ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_write(f.file, buf, count, ppos);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
return ret;
}
SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
size_t, count)
{
return ksys_write(fd, buf, count);
}
ssize_t ksys_pread64(unsigned int fd, char __user *buf, size_t count,
loff_t pos)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PREAD)
ret = vfs_read(f.file, buf, count, &pos);
fdput(f);
}
return ret;
}
SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
size_t, count, loff_t, pos)
{
return ksys_pread64(fd, buf, count, pos);
}
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PREAD64)
COMPAT_SYSCALL_DEFINE5(pread64, unsigned int, fd, char __user *, buf,
size_t, count, compat_arg_u64_dual(pos))
{
return ksys_pread64(fd, buf, count, compat_arg_u64_glue(pos));
}
#endif
ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf,
size_t count, loff_t pos)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PWRITE)
ret = vfs_write(f.file, buf, count, &pos);
fdput(f);
}
return ret;
}
SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
size_t, count, loff_t, pos)
{
return ksys_pwrite64(fd, buf, count, pos);
}
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PWRITE64)
COMPAT_SYSCALL_DEFINE5(pwrite64, unsigned int, fd, const char __user *, buf,
size_t, count, compat_arg_u64_dual(pos))
{
return ksys_pwrite64(fd, buf, count, compat_arg_u64_glue(pos));
}
#endif
static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
loff_t *ppos, int type, rwf_t flags)
{
struct kiocb kiocb;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
ret = kiocb_set_rw_flags(&kiocb, flags);
if (ret)
return ret;
kiocb.ki_pos = (ppos ? *ppos : 0);
if (type == READ)
ret = call_read_iter(filp, &kiocb, iter);
else
ret = call_write_iter(filp, &kiocb, iter);
BUG_ON(ret == -EIOCBQUEUED);
if (ppos)
*ppos = kiocb.ki_pos;
return ret;
}
/* Do it by hand, with file-ops */
static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
loff_t *ppos, int type, rwf_t flags)
{
ssize_t ret = 0;
if (flags & ~RWF_HIPRI)
return -EOPNOTSUPP;
while (iov_iter_count(iter)) {
ssize_t nr;
if (type == READ) {
nr = filp->f_op->read(filp, iter_iov_addr(iter),
iter_iov_len(iter), ppos);
} else {
nr = filp->f_op->write(filp, iter_iov_addr(iter),
iter_iov_len(iter), ppos);
}
if (nr < 0) {
if (!ret)
ret = nr;
break;
}
ret += nr;
if (nr != iter_iov_len(iter))
break;
iov_iter_advance(iter, nr);
}
return ret;
}
static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
loff_t *pos, rwf_t flags)
{
size_t tot_len;
ssize_t ret = 0;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
tot_len = iov_iter_count(iter);
if (!tot_len)
goto out;
ret = rw_verify_area(READ, file, pos, tot_len);
if (ret < 0)
return ret;
if (file->f_op->read_iter)
ret = do_iter_readv_writev(file, iter, pos, READ, flags);
else
ret = do_loop_readv_writev(file, iter, pos, READ, flags);
out:
if (ret >= 0)
fsnotify_access(file);
return ret;
}
ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,
struct iov_iter *iter)
{
size_t tot_len;
ssize_t ret = 0;
if (!file->f_op->read_iter)
return -EINVAL;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
tot_len = iov_iter_count(iter);
if (!tot_len)
goto out;
ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len);
if (ret < 0)
return ret;
ret = call_read_iter(file, iocb, iter);
out:
if (ret >= 0)
fsnotify_access(file);
return ret;
}
EXPORT_SYMBOL(vfs_iocb_iter_read);
ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
rwf_t flags)
{
if (!file->f_op->read_iter)
return -EINVAL;
return do_iter_read(file, iter, ppos, flags);
}
EXPORT_SYMBOL(vfs_iter_read);
static ssize_t do_iter_write(struct file *file, struct iov_iter *iter,
loff_t *pos, rwf_t flags)
{
size_t tot_len;
ssize_t ret = 0;
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
tot_len = iov_iter_count(iter);
if (!tot_len)
return 0;
ret = rw_verify_area(WRITE, file, pos, tot_len);
if (ret < 0)
return ret;
if (file->f_op->write_iter)
ret = do_iter_readv_writev(file, iter, pos, WRITE, flags);
else
ret = do_loop_readv_writev(file, iter, pos, WRITE, flags);
if (ret > 0)
fsnotify_modify(file);
return ret;
}
ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,
struct iov_iter *iter)
{
size_t tot_len;
ssize_t ret = 0;
if (!file->f_op->write_iter)
return -EINVAL;
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
tot_len = iov_iter_count(iter);
if (!tot_len)
return 0;
ret = rw_verify_area(WRITE, file, &iocb->ki_pos, tot_len);
if (ret < 0)
return ret;
ret = call_write_iter(file, iocb, iter);
if (ret > 0)
fsnotify_modify(file);
return ret;
}
EXPORT_SYMBOL(vfs_iocb_iter_write);
ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
rwf_t flags)
{
if (!file->f_op->write_iter)
return -EINVAL;
return do_iter_write(file, iter, ppos, flags);
}
EXPORT_SYMBOL(vfs_iter_write);
static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
ssize_t ret;
ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
if (ret >= 0) {
ret = do_iter_read(file, &iter, pos, flags);
kfree(iov);
}
return ret;
}
static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
ssize_t ret;
ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
if (ret >= 0) {
file_start_write(file);
ret = do_iter_write(file, &iter, pos, flags);
file_end_write(file);
kfree(iov);
}
return ret;
}
static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_readv(f.file, vec, vlen, ppos, flags);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
if (ret > 0)
add_rchar(current, ret);
inc_syscr(current);
return ret;
}
static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_writev(f.file, vec, vlen, ppos, flags);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
if (ret > 0)
add_wchar(current, ret);
inc_syscw(current);
return ret;
}
static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
{
#define HALF_LONG_BITS (BITS_PER_LONG / 2)
return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
}
static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PREAD)
ret = vfs_readv(f.file, vec, vlen, &pos, flags);
fdput(f);
}
if (ret > 0)
add_rchar(current, ret);
inc_syscr(current);
return ret;
}
static ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PWRITE)
ret = vfs_writev(f.file, vec, vlen, &pos, flags);
fdput(f);
}
if (ret > 0)
add_wchar(current, ret);
inc_syscw(current);
return ret;
}
SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen)
{
return do_readv(fd, vec, vlen, 0);
}
SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen)
{
return do_writev(fd, vec, vlen, 0);
}
SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
return do_preadv(fd, vec, vlen, pos, 0);
}
SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
rwf_t, flags)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
if (pos == -1)
return do_readv(fd, vec, vlen, flags);
return do_preadv(fd, vec, vlen, pos, flags);
}
SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
return do_pwritev(fd, vec, vlen, pos, 0);
}
SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
rwf_t, flags)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
if (pos == -1)
return do_writev(fd, vec, vlen, flags);
return do_pwritev(fd, vec, vlen, pos, flags);
}
/*
* Various compat syscalls. Note that they all pretend to take a native
* iovec - import_iovec will properly treat those as compat_iovecs based on
* in_compat_syscall().
*/
#ifdef CONFIG_COMPAT
#ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
const struct iovec __user *, vec,
unsigned long, vlen, loff_t, pos)
{
return do_preadv(fd, vec, vlen, pos, 0);
}
#endif
COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
const struct iovec __user *, vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
return do_preadv(fd, vec, vlen, pos, 0);
}
#ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V2
COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
const struct iovec __user *, vec,
unsigned long, vlen, loff_t, pos, rwf_t, flags)
{
if (pos == -1)
return do_readv(fd, vec, vlen, flags);
return do_preadv(fd, vec, vlen, pos, flags);
}
#endif
COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd,
const struct iovec __user *, vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high,
rwf_t, flags)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
if (pos == -1)
return do_readv(fd, vec, vlen, flags);
return do_preadv(fd, vec, vlen, pos, flags);
}
#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64
COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
const struct iovec __user *, vec,
unsigned long, vlen, loff_t, pos)
{
return do_pwritev(fd, vec, vlen, pos, 0);
}
#endif
COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
const struct iovec __user *,vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
return do_pwritev(fd, vec, vlen, pos, 0);
}
#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V2
COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,
const struct iovec __user *, vec,
unsigned long, vlen, loff_t, pos, rwf_t, flags)
{
if (pos == -1)
return do_writev(fd, vec, vlen, flags);
return do_pwritev(fd, vec, vlen, pos, flags);
}
#endif
COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd,
const struct iovec __user *,vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
if (pos == -1)
return do_writev(fd, vec, vlen, flags);
return do_pwritev(fd, vec, vlen, pos, flags);
}
#endif /* CONFIG_COMPAT */
static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
size_t count, loff_t max)
{
struct fd in, out;
struct inode *in_inode, *out_inode;
struct pipe_inode_info *opipe;
loff_t pos;
loff_t out_pos;
ssize_t retval;
int fl;
/*
* Get input file, and verify that it is ok..
*/
retval = -EBADF;
in = fdget(in_fd);
if (!in.file)
goto out;
if (!(in.file->f_mode & FMODE_READ))
goto fput_in;
retval = -ESPIPE;
if (!ppos) {
pos = in.file->f_pos;
} else {
pos = *ppos;
if (!(in.file->f_mode & FMODE_PREAD))
goto fput_in;
}
retval = rw_verify_area(READ, in.file, &pos, count);
if (retval < 0)
goto fput_in;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
/*
* Get output file, and verify that it is ok..
*/
retval = -EBADF;
out = fdget(out_fd);
if (!out.file)
goto fput_in;
if (!(out.file->f_mode & FMODE_WRITE))
goto fput_out;
in_inode = file_inode(in.file);
out_inode = file_inode(out.file);
out_pos = out.file->f_pos;
if (!max)
max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
if (unlikely(pos + count > max)) {
retval = -EOVERFLOW;
if (pos >= max)
goto fput_out;
count = max - pos;
}
fl = 0;
#if 0
/*
* We need to debate whether we can enable this or not. The
* man page documents EAGAIN return for the output at least,
* and the application is arguably buggy if it doesn't expect
* EAGAIN on a non-blocking file descriptor.
*/
if (in.file->f_flags & O_NONBLOCK)
fl = SPLICE_F_NONBLOCK;
#endif
opipe = get_pipe_info(out.file, true);
if (!opipe) {
retval = rw_verify_area(WRITE, out.file, &out_pos, count);
if (retval < 0)
goto fput_out;
file_start_write(out.file);
retval = do_splice_direct(in.file, &pos, out.file, &out_pos,
count, fl);
file_end_write(out.file);
} else {
if (out.file->f_flags & O_NONBLOCK)
fl |= SPLICE_F_NONBLOCK;
retval = splice_file_to_pipe(in.file, opipe, &pos, count, fl);
}
if (retval > 0) {
add_rchar(current, retval);
add_wchar(current, retval);
fsnotify_access(in.file);
fsnotify_modify(out.file);
out.file->f_pos = out_pos;
if (ppos)
*ppos = pos;
else
in.file->f_pos = pos;
}
inc_syscr(current);
inc_syscw(current);
if (pos > max)
retval = -EOVERFLOW;
fput_out:
fdput(out);
fput_in:
fdput(in);
out:
return retval;
}
SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
{
loff_t pos;
off_t off;
ssize_t ret;
if (offset) {
if (unlikely(get_user(off, offset)))
return -EFAULT;
pos = off;
ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
{
loff_t pos;
ssize_t ret;
if (offset) {
if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
return -EFAULT;
ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd,
compat_off_t __user *, offset, compat_size_t, count)
{
loff_t pos;
off_t off;
ssize_t ret;
if (offset) {
if (unlikely(get_user(off, offset)))
return -EFAULT;
pos = off;
ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
compat_loff_t __user *, offset, compat_size_t, count)
{
loff_t pos;
ssize_t ret;
if (offset) {
if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
return -EFAULT;
ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
#endif
/**
* generic_copy_file_range - copy data between two files
* @file_in: file structure to read from
* @pos_in: file offset to read from
* @file_out: file structure to write data to
* @pos_out: file offset to write data to
* @len: amount of data to copy
* @flags: copy flags
*
* This is a generic filesystem helper to copy data from one file to another.
* It has no constraints on the source or destination file owners - the files
* can belong to different superblocks and different filesystem types. Short
* copies are allowed.
*
* This should be called from the @file_out filesystem, as per the
* ->copy_file_range() method.
*
* Returns the number of bytes copied or a negative error indicating the
* failure.
*/
ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
lockdep_assert(sb_write_started(file_inode(file_out)->i_sb));
return do_splice_direct(file_in, &pos_in, file_out, &pos_out,
len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0);
}
EXPORT_SYMBOL(generic_copy_file_range);
/*
* Performs necessary checks before doing a file copy
*
* Can adjust amount of bytes to copy via @req_count argument.
* Returns appropriate error code that caller should return or
* zero in case the copy should be allowed.
*/
static int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t *req_count, unsigned int flags)
{
struct inode *inode_in = file_inode(file_in);
struct inode *inode_out = file_inode(file_out);
uint64_t count = *req_count;
loff_t size_in;
int ret;
ret = generic_file_rw_checks(file_in, file_out);
if (ret)
return ret;
/*
* We allow some filesystems to handle cross sb copy, but passing
* a file of the wrong filesystem type to filesystem driver can result
* in an attempt to dereference the wrong type of ->private_data, so
* avoid doing that until we really have a good reason.
*
* nfs and cifs define several different file_system_type structures
* and several different sets of file_operations, but they all end up
* using the same ->copy_file_range() function pointer.
*/
if (flags & COPY_FILE_SPLICE) {
/* cross sb splice is allowed */
} else if (file_out->f_op->copy_file_range) {
if (file_in->f_op->copy_file_range !=
file_out->f_op->copy_file_range)
return -EXDEV;
} else if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) {
return -EXDEV;
}
/* Don't touch certain kinds of inodes */
if (IS_IMMUTABLE(inode_out))
return -EPERM;
if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
return -ETXTBSY;
/* Ensure offsets don't wrap. */
if (pos_in + count < pos_in || pos_out + count < pos_out)
return -EOVERFLOW;
/* Shorten the copy to EOF */
size_in = i_size_read(inode_in);
if (pos_in >= size_in)
count = 0;
else
count = min(count, size_in - (uint64_t)pos_in);
ret = generic_write_check_limits(file_out, pos_out, &count);
if (ret)
return ret;
/* Don't allow overlapped copying within the same file. */
if (inode_in == inode_out &&
pos_out + count > pos_in &&
pos_out < pos_in + count)
return -EINVAL;
*req_count = count;
return 0;
}
/*
* copy_file_range() differs from regular file read and write in that it
* specifically allows return partial success. When it does so is up to
* the copy_file_range method.
*/
ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
ssize_t ret;
bool splice = flags & COPY_FILE_SPLICE;
if (flags & ~COPY_FILE_SPLICE)
return -EINVAL;
ret = generic_copy_file_checks(file_in, pos_in, file_out, pos_out, &len,
flags);
if (unlikely(ret))
return ret;
ret = rw_verify_area(READ, file_in, &pos_in, len);
if (unlikely(ret))
return ret;
ret = rw_verify_area(WRITE, file_out, &pos_out, len);
if (unlikely(ret))
return ret;
if (len == 0)
return 0;
file_start_write(file_out);
/*
* Cloning is supported by more file systems, so we implement copy on
* same sb using clone, but for filesystems where both clone and copy
* are supported (e.g. nfs,cifs), we only call the copy method.
*/
if (!splice && file_out->f_op->copy_file_range) {
ret = file_out->f_op->copy_file_range(file_in, pos_in,
file_out, pos_out,
len, flags);
goto done;
}
if (!splice && file_in->f_op->remap_file_range &&
file_inode(file_in)->i_sb == file_inode(file_out)->i_sb) {
ret = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out,
min_t(loff_t, MAX_RW_COUNT, len),
REMAP_FILE_CAN_SHORTEN);
if (ret > 0)
goto done;
}
/*
* We can get here for same sb copy of filesystems that do not implement
* ->copy_file_range() in case filesystem does not support clone or in
* case filesystem supports clone but rejected the clone request (e.g.
* because it was not block aligned).
*
* In both cases, fall back to kernel copy so we are able to maintain a
* consistent story about which filesystems support copy_file_range()
* and which filesystems do not, that will allow userspace tools to
* make consistent desicions w.r.t using copy_file_range().
*
* We also get here if caller (e.g. nfsd) requested COPY_FILE_SPLICE.
*/
ret = generic_copy_file_range(file_in, pos_in, file_out, pos_out, len,
flags);
done:
if (ret > 0) {
fsnotify_access(file_in);
add_rchar(current, ret);
fsnotify_modify(file_out);
add_wchar(current, ret);
}
inc_syscr(current);
inc_syscw(current);
file_end_write(file_out);
return ret;
}
EXPORT_SYMBOL(vfs_copy_file_range);
SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in,
int, fd_out, loff_t __user *, off_out,
size_t, len, unsigned int, flags)
{
loff_t pos_in;
loff_t pos_out;
struct fd f_in;
struct fd f_out;
ssize_t ret = -EBADF;
f_in = fdget(fd_in);
if (!f_in.file)
goto out2;
f_out = fdget(fd_out);
if (!f_out.file)
goto out1;
ret = -EFAULT;
if (off_in) {
if (copy_from_user(&pos_in, off_in, sizeof(loff_t)))
goto out;
} else {
pos_in = f_in.file->f_pos;
}
if (off_out) {
if (copy_from_user(&pos_out, off_out, sizeof(loff_t)))
goto out;
} else {
pos_out = f_out.file->f_pos;
}
ret = -EINVAL;
if (flags != 0)
goto out;
ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len,
flags);
if (ret > 0) {
pos_in += ret;
pos_out += ret;
if (off_in) {
if (copy_to_user(off_in, &pos_in, sizeof(loff_t)))
ret = -EFAULT;
} else {
f_in.file->f_pos = pos_in;
}
if (off_out) {
if (copy_to_user(off_out, &pos_out, sizeof(loff_t)))
ret = -EFAULT;
} else {
f_out.file->f_pos = pos_out;
}
}
out:
fdput(f_out);
out1:
fdput(f_in);
out2:
return ret;
}
/*
* Don't operate on ranges the page cache doesn't support, and don't exceed the
* LFS limits. If pos is under the limit it becomes a short access. If it
* exceeds the limit we return -EFBIG.
*/
int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
{
struct inode *inode = file->f_mapping->host;
loff_t max_size = inode->i_sb->s_maxbytes;
loff_t limit = rlimit(RLIMIT_FSIZE);
if (limit != RLIM_INFINITY) {
if (pos >= limit) {
send_sig(SIGXFSZ, current, 0);
return -EFBIG;
}
*count = min(*count, limit - pos);
}
if (!(file->f_flags & O_LARGEFILE))
max_size = MAX_NON_LFS;
if (unlikely(pos >= max_size))
return -EFBIG;
*count = min(*count, max_size - pos);
return 0;
}
/* Like generic_write_checks(), but takes size of write instead of iter. */
int generic_write_checks_count(struct kiocb *iocb, loff_t *count)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
if (IS_SWAPFILE(inode))
return -ETXTBSY;
if (!*count)
return 0;
if (iocb->ki_flags & IOCB_APPEND)
iocb->ki_pos = i_size_read(inode);
if ((iocb->ki_flags & IOCB_NOWAIT) &&
!((iocb->ki_flags & IOCB_DIRECT) ||
(file->f_mode & FMODE_BUF_WASYNC)))
return -EINVAL;
return generic_write_check_limits(iocb->ki_filp, iocb->ki_pos, count);
}
EXPORT_SYMBOL(generic_write_checks_count);
/*
* Performs necessary checks before doing a write
*
* Can adjust writing position or amount of bytes to write.
* Returns appropriate error code that caller should return or
* zero in case that write should be allowed.
*/
ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
{
loff_t count = iov_iter_count(from);
int ret;
ret = generic_write_checks_count(iocb, &count);
if (ret)
return ret;
iov_iter_truncate(from, count);
return iov_iter_count(from);
}
EXPORT_SYMBOL(generic_write_checks);
/*
* Performs common checks before doing a file copy/clone
* from @file_in to @file_out.
*/
int generic_file_rw_checks(struct file *file_in, struct file *file_out)
{
struct inode *inode_in = file_inode(file_in);
struct inode *inode_out = file_inode(file_out);
/* Don't copy dirs, pipes, sockets... */
if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
return -EISDIR;
if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
return -EINVAL;
if (!(file_in->f_mode & FMODE_READ) ||
!(file_out->f_mode & FMODE_WRITE) ||
(file_out->f_flags & O_APPEND))
return -EBADF;
return 0;
}
| linux-master | fs/read_write.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2002,2003 by Andreas Gruenbacher <[email protected]>
*
* Fixes from William Schumacher incorporated on 15 March 2001.
* (Reported by Charles Bertsch, <[email protected]>).
*/
/*
* This file contains generic functions for manipulating
* POSIX 1003.1e draft standard 17 ACLs.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/export.h>
#include <linux/user_namespace.h>
#include <linux/namei.h>
#include <linux/mnt_idmapping.h>
#include <linux/iversion.h>
#include <linux/security.h>
#include <linux/evm.h>
#include <linux/fsnotify.h>
#include <linux/filelock.h>
#include "internal.h"
static struct posix_acl **acl_by_type(struct inode *inode, int type)
{
switch (type) {
case ACL_TYPE_ACCESS:
return &inode->i_acl;
case ACL_TYPE_DEFAULT:
return &inode->i_default_acl;
default:
BUG();
}
}
struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
struct posix_acl **p = acl_by_type(inode, type);
struct posix_acl *acl;
for (;;) {
rcu_read_lock();
acl = rcu_dereference(*p);
if (!acl || is_uncached_acl(acl) ||
refcount_inc_not_zero(&acl->a_refcount))
break;
rcu_read_unlock();
cpu_relax();
}
rcu_read_unlock();
return acl;
}
EXPORT_SYMBOL(get_cached_acl);
struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
{
struct posix_acl *acl = rcu_dereference(*acl_by_type(inode, type));
if (acl == ACL_DONT_CACHE) {
struct posix_acl *ret;
ret = inode->i_op->get_inode_acl(inode, type, LOOKUP_RCU);
if (!IS_ERR(ret))
acl = ret;
}
return acl;
}
EXPORT_SYMBOL(get_cached_acl_rcu);
void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
{
struct posix_acl **p = acl_by_type(inode, type);
struct posix_acl *old;
old = xchg(p, posix_acl_dup(acl));
if (!is_uncached_acl(old))
posix_acl_release(old);
}
EXPORT_SYMBOL(set_cached_acl);
static void __forget_cached_acl(struct posix_acl **p)
{
struct posix_acl *old;
old = xchg(p, ACL_NOT_CACHED);
if (!is_uncached_acl(old))
posix_acl_release(old);
}
void forget_cached_acl(struct inode *inode, int type)
{
__forget_cached_acl(acl_by_type(inode, type));
}
EXPORT_SYMBOL(forget_cached_acl);
void forget_all_cached_acls(struct inode *inode)
{
__forget_cached_acl(&inode->i_acl);
__forget_cached_acl(&inode->i_default_acl);
}
EXPORT_SYMBOL(forget_all_cached_acls);
static struct posix_acl *__get_acl(struct mnt_idmap *idmap,
struct dentry *dentry, struct inode *inode,
int type)
{
struct posix_acl *sentinel;
struct posix_acl **p;
struct posix_acl *acl;
/*
* The sentinel is used to detect when another operation like
* set_cached_acl() or forget_cached_acl() races with get_inode_acl().
* It is guaranteed that is_uncached_acl(sentinel) is true.
*/
acl = get_cached_acl(inode, type);
if (!is_uncached_acl(acl))
return acl;
if (!IS_POSIXACL(inode))
return NULL;
sentinel = uncached_acl_sentinel(current);
p = acl_by_type(inode, type);
/*
* If the ACL isn't being read yet, set our sentinel. Otherwise, the
* current value of the ACL will not be ACL_NOT_CACHED and so our own
* sentinel will not be set; another task will update the cache. We
* could wait for that other task to complete its job, but it's easier
* to just call ->get_inode_acl to fetch the ACL ourself. (This is
* going to be an unlikely race.)
*/
cmpxchg(p, ACL_NOT_CACHED, sentinel);
/*
* Normally, the ACL returned by ->get{_inode}_acl will be cached.
* A filesystem can prevent that by calling
* forget_cached_acl(inode, type) in ->get{_inode}_acl.
*
* If the filesystem doesn't have a get{_inode}_ acl() function at all,
* we'll just create the negative cache entry.
*/
if (dentry && inode->i_op->get_acl) {
acl = inode->i_op->get_acl(idmap, dentry, type);
} else if (inode->i_op->get_inode_acl) {
acl = inode->i_op->get_inode_acl(inode, type, false);
} else {
set_cached_acl(inode, type, NULL);
return NULL;
}
if (IS_ERR(acl)) {
/*
* Remove our sentinel so that we don't block future attempts
* to cache the ACL.
*/
cmpxchg(p, sentinel, ACL_NOT_CACHED);
return acl;
}
/*
* Cache the result, but only if our sentinel is still in place.
*/
posix_acl_dup(acl);
if (unlikely(!try_cmpxchg(p, &sentinel, acl)))
posix_acl_release(acl);
return acl;
}
struct posix_acl *get_inode_acl(struct inode *inode, int type)
{
return __get_acl(&nop_mnt_idmap, NULL, inode, type);
}
EXPORT_SYMBOL(get_inode_acl);
/*
* Init a fresh posix_acl
*/
void
posix_acl_init(struct posix_acl *acl, int count)
{
refcount_set(&acl->a_refcount, 1);
acl->a_count = count;
}
EXPORT_SYMBOL(posix_acl_init);
/*
* Allocate a new ACL with the specified number of entries.
*/
struct posix_acl *
posix_acl_alloc(int count, gfp_t flags)
{
const size_t size = sizeof(struct posix_acl) +
count * sizeof(struct posix_acl_entry);
struct posix_acl *acl = kmalloc(size, flags);
if (acl)
posix_acl_init(acl, count);
return acl;
}
EXPORT_SYMBOL(posix_acl_alloc);
/*
* Clone an ACL.
*/
struct posix_acl *
posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
{
struct posix_acl *clone = NULL;
if (acl) {
int size = sizeof(struct posix_acl) + acl->a_count *
sizeof(struct posix_acl_entry);
clone = kmemdup(acl, size, flags);
if (clone)
refcount_set(&clone->a_refcount, 1);
}
return clone;
}
EXPORT_SYMBOL_GPL(posix_acl_clone);
/*
* Check if an acl is valid. Returns 0 if it is, or -E... otherwise.
*/
int
posix_acl_valid(struct user_namespace *user_ns, const struct posix_acl *acl)
{
const struct posix_acl_entry *pa, *pe;
int state = ACL_USER_OBJ;
int needs_mask = 0;
FOREACH_ACL_ENTRY(pa, acl, pe) {
if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE))
return -EINVAL;
switch (pa->e_tag) {
case ACL_USER_OBJ:
if (state == ACL_USER_OBJ) {
state = ACL_USER;
break;
}
return -EINVAL;
case ACL_USER:
if (state != ACL_USER)
return -EINVAL;
if (!kuid_has_mapping(user_ns, pa->e_uid))
return -EINVAL;
needs_mask = 1;
break;
case ACL_GROUP_OBJ:
if (state == ACL_USER) {
state = ACL_GROUP;
break;
}
return -EINVAL;
case ACL_GROUP:
if (state != ACL_GROUP)
return -EINVAL;
if (!kgid_has_mapping(user_ns, pa->e_gid))
return -EINVAL;
needs_mask = 1;
break;
case ACL_MASK:
if (state != ACL_GROUP)
return -EINVAL;
state = ACL_OTHER;
break;
case ACL_OTHER:
if (state == ACL_OTHER ||
(state == ACL_GROUP && !needs_mask)) {
state = 0;
break;
}
return -EINVAL;
default:
return -EINVAL;
}
}
if (state == 0)
return 0;
return -EINVAL;
}
EXPORT_SYMBOL(posix_acl_valid);
/*
* Returns 0 if the acl can be exactly represented in the traditional
* file mode permission bits, or else 1. Returns -E... on error.
*/
int
posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p)
{
const struct posix_acl_entry *pa, *pe;
umode_t mode = 0;
int not_equiv = 0;
/*
* A null ACL can always be presented as mode bits.
*/
if (!acl)
return 0;
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch (pa->e_tag) {
case ACL_USER_OBJ:
mode |= (pa->e_perm & S_IRWXO) << 6;
break;
case ACL_GROUP_OBJ:
mode |= (pa->e_perm & S_IRWXO) << 3;
break;
case ACL_OTHER:
mode |= pa->e_perm & S_IRWXO;
break;
case ACL_MASK:
mode = (mode & ~S_IRWXG) |
((pa->e_perm & S_IRWXO) << 3);
not_equiv = 1;
break;
case ACL_USER:
case ACL_GROUP:
not_equiv = 1;
break;
default:
return -EINVAL;
}
}
if (mode_p)
*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
return not_equiv;
}
EXPORT_SYMBOL(posix_acl_equiv_mode);
/*
* Create an ACL representing the file mode permission bits of an inode.
*/
struct posix_acl *
posix_acl_from_mode(umode_t mode, gfp_t flags)
{
struct posix_acl *acl = posix_acl_alloc(3, flags);
if (!acl)
return ERR_PTR(-ENOMEM);
acl->a_entries[0].e_tag = ACL_USER_OBJ;
acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6;
acl->a_entries[1].e_tag = ACL_GROUP_OBJ;
acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3;
acl->a_entries[2].e_tag = ACL_OTHER;
acl->a_entries[2].e_perm = (mode & S_IRWXO);
return acl;
}
EXPORT_SYMBOL(posix_acl_from_mode);
/*
* Return 0 if current is granted want access to the inode
* by the acl. Returns -E... otherwise.
*/
int
posix_acl_permission(struct mnt_idmap *idmap, struct inode *inode,
const struct posix_acl *acl, int want)
{
const struct posix_acl_entry *pa, *pe, *mask_obj;
struct user_namespace *fs_userns = i_user_ns(inode);
int found = 0;
vfsuid_t vfsuid;
vfsgid_t vfsgid;
want &= MAY_READ | MAY_WRITE | MAY_EXEC;
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
case ACL_USER_OBJ:
/* (May have been checked already) */
vfsuid = i_uid_into_vfsuid(idmap, inode);
if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
goto check_perm;
break;
case ACL_USER:
vfsuid = make_vfsuid(idmap, fs_userns,
pa->e_uid);
if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
goto mask;
break;
case ACL_GROUP_OBJ:
vfsgid = i_gid_into_vfsgid(idmap, inode);
if (vfsgid_in_group_p(vfsgid)) {
found = 1;
if ((pa->e_perm & want) == want)
goto mask;
}
break;
case ACL_GROUP:
vfsgid = make_vfsgid(idmap, fs_userns,
pa->e_gid);
if (vfsgid_in_group_p(vfsgid)) {
found = 1;
if ((pa->e_perm & want) == want)
goto mask;
}
break;
case ACL_MASK:
break;
case ACL_OTHER:
if (found)
return -EACCES;
else
goto check_perm;
default:
return -EIO;
}
}
return -EIO;
mask:
for (mask_obj = pa+1; mask_obj != pe; mask_obj++) {
if (mask_obj->e_tag == ACL_MASK) {
if ((pa->e_perm & mask_obj->e_perm & want) == want)
return 0;
return -EACCES;
}
}
check_perm:
if ((pa->e_perm & want) == want)
return 0;
return -EACCES;
}
/*
* Modify acl when creating a new inode. The caller must ensure the acl is
* only referenced once.
*
* mode_p initially must contain the mode parameter to the open() / creat()
* system calls. All permissions that are not granted by the acl are removed.
* The permissions in the acl are changed to reflect the mode_p parameter.
*/
static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
{
struct posix_acl_entry *pa, *pe;
struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
umode_t mode = *mode_p;
int not_equiv = 0;
/* assert(atomic_read(acl->a_refcount) == 1); */
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
case ACL_USER_OBJ:
pa->e_perm &= (mode >> 6) | ~S_IRWXO;
mode &= (pa->e_perm << 6) | ~S_IRWXU;
break;
case ACL_USER:
case ACL_GROUP:
not_equiv = 1;
break;
case ACL_GROUP_OBJ:
group_obj = pa;
break;
case ACL_OTHER:
pa->e_perm &= mode | ~S_IRWXO;
mode &= pa->e_perm | ~S_IRWXO;
break;
case ACL_MASK:
mask_obj = pa;
not_equiv = 1;
break;
default:
return -EIO;
}
}
if (mask_obj) {
mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
} else {
if (!group_obj)
return -EIO;
group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
}
*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
return not_equiv;
}
/*
* Modify the ACL for the chmod syscall.
*/
static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
{
struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
struct posix_acl_entry *pa, *pe;
/* assert(atomic_read(acl->a_refcount) == 1); */
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
case ACL_USER_OBJ:
pa->e_perm = (mode & S_IRWXU) >> 6;
break;
case ACL_USER:
case ACL_GROUP:
break;
case ACL_GROUP_OBJ:
group_obj = pa;
break;
case ACL_MASK:
mask_obj = pa;
break;
case ACL_OTHER:
pa->e_perm = (mode & S_IRWXO);
break;
default:
return -EIO;
}
}
if (mask_obj) {
mask_obj->e_perm = (mode & S_IRWXG) >> 3;
} else {
if (!group_obj)
return -EIO;
group_obj->e_perm = (mode & S_IRWXG) >> 3;
}
return 0;
}
int
__posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p)
{
struct posix_acl *clone = posix_acl_clone(*acl, gfp);
int err = -ENOMEM;
if (clone) {
err = posix_acl_create_masq(clone, mode_p);
if (err < 0) {
posix_acl_release(clone);
clone = NULL;
}
}
posix_acl_release(*acl);
*acl = clone;
return err;
}
EXPORT_SYMBOL(__posix_acl_create);
int
__posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode)
{
struct posix_acl *clone = posix_acl_clone(*acl, gfp);
int err = -ENOMEM;
if (clone) {
err = __posix_acl_chmod_masq(clone, mode);
if (err) {
posix_acl_release(clone);
clone = NULL;
}
}
posix_acl_release(*acl);
*acl = clone;
return err;
}
EXPORT_SYMBOL(__posix_acl_chmod);
/**
* posix_acl_chmod - chmod a posix acl
*
* @idmap: idmap of the mount @inode was found from
* @dentry: dentry to check permissions on
* @mode: the new mode of @inode
*
* If the dentry has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before checking
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply passs @nop_mnt_idmap.
*/
int
posix_acl_chmod(struct mnt_idmap *idmap, struct dentry *dentry,
umode_t mode)
{
struct inode *inode = d_inode(dentry);
struct posix_acl *acl;
int ret = 0;
if (!IS_POSIXACL(inode))
return 0;
if (!inode->i_op->set_acl)
return -EOPNOTSUPP;
acl = get_inode_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR_OR_NULL(acl)) {
if (acl == ERR_PTR(-EOPNOTSUPP))
return 0;
return PTR_ERR(acl);
}
ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode);
if (ret)
return ret;
ret = inode->i_op->set_acl(idmap, dentry, acl, ACL_TYPE_ACCESS);
posix_acl_release(acl);
return ret;
}
EXPORT_SYMBOL(posix_acl_chmod);
int
posix_acl_create(struct inode *dir, umode_t *mode,
struct posix_acl **default_acl, struct posix_acl **acl)
{
struct posix_acl *p;
struct posix_acl *clone;
int ret;
*acl = NULL;
*default_acl = NULL;
if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
return 0;
p = get_inode_acl(dir, ACL_TYPE_DEFAULT);
if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
*mode &= ~current_umask();
return 0;
}
if (IS_ERR(p))
return PTR_ERR(p);
ret = -ENOMEM;
clone = posix_acl_clone(p, GFP_NOFS);
if (!clone)
goto err_release;
ret = posix_acl_create_masq(clone, mode);
if (ret < 0)
goto err_release_clone;
if (ret == 0)
posix_acl_release(clone);
else
*acl = clone;
if (!S_ISDIR(*mode))
posix_acl_release(p);
else
*default_acl = p;
return 0;
err_release_clone:
posix_acl_release(clone);
err_release:
posix_acl_release(p);
return ret;
}
EXPORT_SYMBOL_GPL(posix_acl_create);
/**
* posix_acl_update_mode - update mode in set_acl
* @idmap: idmap of the mount @inode was found from
* @inode: target inode
* @mode_p: mode (pointer) for update
* @acl: acl pointer
*
* Update the file mode when setting an ACL: compute the new file permission
* bits based on the ACL. In addition, if the ACL is equivalent to the new
* file mode, set *@acl to NULL to indicate that no ACL should be set.
*
* As with chmod, clear the setgid bit if the caller is not in the owning group
* or capable of CAP_FSETID (see inode_change_ok).
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before checking
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply passs @nop_mnt_idmap.
*
* Called from set_acl inode operations.
*/
int posix_acl_update_mode(struct mnt_idmap *idmap,
struct inode *inode, umode_t *mode_p,
struct posix_acl **acl)
{
umode_t mode = inode->i_mode;
int error;
error = posix_acl_equiv_mode(*acl, &mode);
if (error < 0)
return error;
if (error == 0)
*acl = NULL;
if (!vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)) &&
!capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))
mode &= ~S_ISGID;
*mode_p = mode;
return 0;
}
EXPORT_SYMBOL(posix_acl_update_mode);
/*
* Fix up the uids and gids in posix acl extended attributes in place.
*/
static int posix_acl_fix_xattr_common(const void *value, size_t size)
{
const struct posix_acl_xattr_header *header = value;
int count;
if (!header)
return -EINVAL;
if (size < sizeof(struct posix_acl_xattr_header))
return -EINVAL;
if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
return -EOPNOTSUPP;
count = posix_acl_xattr_count(size);
if (count < 0)
return -EINVAL;
if (count == 0)
return 0;
return count;
}
/**
* posix_acl_from_xattr - convert POSIX ACLs from backing store to VFS format
* @userns: the filesystem's idmapping
* @value: the uapi representation of POSIX ACLs
* @size: the size of @void
*
* Filesystems that store POSIX ACLs in the unaltered uapi format should use
* posix_acl_from_xattr() when reading them from the backing store and
* converting them into the struct posix_acl VFS format. The helper is
* specifically intended to be called from the acl inode operation.
*
* The posix_acl_from_xattr() function will map the raw {g,u}id values stored
* in ACL_{GROUP,USER} entries into idmapping in @userns.
*
* Note that posix_acl_from_xattr() does not take idmapped mounts into account.
* If it did it calling it from the get acl inode operation would return POSIX
* ACLs mapped according to an idmapped mount which would mean that the value
* couldn't be cached for the filesystem. Idmapped mounts are taken into
* account on the fly during permission checking or right at the VFS -
* userspace boundary before reporting them to the user.
*
* Return: Allocated struct posix_acl on success, NULL for a valid header but
* without actual POSIX ACL entries, or ERR_PTR() encoded error code.
*/
struct posix_acl *posix_acl_from_xattr(struct user_namespace *userns,
const void *value, size_t size)
{
const struct posix_acl_xattr_header *header = value;
const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
int count;
struct posix_acl *acl;
struct posix_acl_entry *acl_e;
count = posix_acl_fix_xattr_common(value, size);
if (count < 0)
return ERR_PTR(count);
if (count == 0)
return NULL;
acl = posix_acl_alloc(count, GFP_NOFS);
if (!acl)
return ERR_PTR(-ENOMEM);
acl_e = acl->a_entries;
for (end = entry + count; entry != end; acl_e++, entry++) {
acl_e->e_tag = le16_to_cpu(entry->e_tag);
acl_e->e_perm = le16_to_cpu(entry->e_perm);
switch(acl_e->e_tag) {
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
break;
case ACL_USER:
acl_e->e_uid = make_kuid(userns,
le32_to_cpu(entry->e_id));
if (!uid_valid(acl_e->e_uid))
goto fail;
break;
case ACL_GROUP:
acl_e->e_gid = make_kgid(userns,
le32_to_cpu(entry->e_id));
if (!gid_valid(acl_e->e_gid))
goto fail;
break;
default:
goto fail;
}
}
return acl;
fail:
posix_acl_release(acl);
return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL (posix_acl_from_xattr);
/*
* Convert from in-memory to extended attribute representation.
*/
int
posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
void *buffer, size_t size)
{
struct posix_acl_xattr_header *ext_acl = buffer;
struct posix_acl_xattr_entry *ext_entry;
int real_size, n;
real_size = posix_acl_xattr_size(acl->a_count);
if (!buffer)
return real_size;
if (real_size > size)
return -ERANGE;
ext_entry = (void *)(ext_acl + 1);
ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
for (n=0; n < acl->a_count; n++, ext_entry++) {
const struct posix_acl_entry *acl_e = &acl->a_entries[n];
ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
switch(acl_e->e_tag) {
case ACL_USER:
ext_entry->e_id =
cpu_to_le32(from_kuid(user_ns, acl_e->e_uid));
break;
case ACL_GROUP:
ext_entry->e_id =
cpu_to_le32(from_kgid(user_ns, acl_e->e_gid));
break;
default:
ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
break;
}
}
return real_size;
}
EXPORT_SYMBOL (posix_acl_to_xattr);
/**
* vfs_posix_acl_to_xattr - convert from kernel to userspace representation
* @idmap: idmap of the mount
* @inode: inode the posix acls are set on
* @acl: the posix acls as represented by the vfs
* @buffer: the buffer into which to convert @acl
* @size: size of @buffer
*
* This converts @acl from the VFS representation in the filesystem idmapping
* to the uapi form reportable to userspace. And mount and caller idmappings
* are handled appropriately.
*
* Return: On success, the size of the stored uapi posix acls, on error a
* negative errno.
*/
static ssize_t vfs_posix_acl_to_xattr(struct mnt_idmap *idmap,
struct inode *inode,
const struct posix_acl *acl, void *buffer,
size_t size)
{
struct posix_acl_xattr_header *ext_acl = buffer;
struct posix_acl_xattr_entry *ext_entry;
struct user_namespace *fs_userns, *caller_userns;
ssize_t real_size, n;
vfsuid_t vfsuid;
vfsgid_t vfsgid;
real_size = posix_acl_xattr_size(acl->a_count);
if (!buffer)
return real_size;
if (real_size > size)
return -ERANGE;
ext_entry = (void *)(ext_acl + 1);
ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
fs_userns = i_user_ns(inode);
caller_userns = current_user_ns();
for (n=0; n < acl->a_count; n++, ext_entry++) {
const struct posix_acl_entry *acl_e = &acl->a_entries[n];
ext_entry->e_tag = cpu_to_le16(acl_e->e_tag);
ext_entry->e_perm = cpu_to_le16(acl_e->e_perm);
switch(acl_e->e_tag) {
case ACL_USER:
vfsuid = make_vfsuid(idmap, fs_userns, acl_e->e_uid);
ext_entry->e_id = cpu_to_le32(from_kuid(
caller_userns, vfsuid_into_kuid(vfsuid)));
break;
case ACL_GROUP:
vfsgid = make_vfsgid(idmap, fs_userns, acl_e->e_gid);
ext_entry->e_id = cpu_to_le32(from_kgid(
caller_userns, vfsgid_into_kgid(vfsgid)));
break;
default:
ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
break;
}
}
return real_size;
}
int
set_posix_acl(struct mnt_idmap *idmap, struct dentry *dentry,
int type, struct posix_acl *acl)
{
struct inode *inode = d_inode(dentry);
if (!IS_POSIXACL(inode))
return -EOPNOTSUPP;
if (!inode->i_op->set_acl)
return -EOPNOTSUPP;
if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
return acl ? -EACCES : 0;
if (!inode_owner_or_capable(idmap, inode))
return -EPERM;
if (acl) {
int ret = posix_acl_valid(inode->i_sb->s_user_ns, acl);
if (ret)
return ret;
}
return inode->i_op->set_acl(idmap, dentry, acl, type);
}
EXPORT_SYMBOL(set_posix_acl);
int posix_acl_listxattr(struct inode *inode, char **buffer,
ssize_t *remaining_size)
{
int err;
if (!IS_POSIXACL(inode))
return 0;
if (inode->i_acl) {
err = xattr_list_one(buffer, remaining_size,
XATTR_NAME_POSIX_ACL_ACCESS);
if (err)
return err;
}
if (inode->i_default_acl) {
err = xattr_list_one(buffer, remaining_size,
XATTR_NAME_POSIX_ACL_DEFAULT);
if (err)
return err;
}
return 0;
}
static bool
posix_acl_xattr_list(struct dentry *dentry)
{
return IS_POSIXACL(d_backing_inode(dentry));
}
/*
* nop_posix_acl_access - legacy xattr handler for access POSIX ACLs
*
* This is the legacy POSIX ACL access xattr handler. It is used by some
* filesystems to implement their ->listxattr() inode operation. New code
* should never use them.
*/
const struct xattr_handler nop_posix_acl_access = {
.name = XATTR_NAME_POSIX_ACL_ACCESS,
.list = posix_acl_xattr_list,
};
EXPORT_SYMBOL_GPL(nop_posix_acl_access);
/*
* nop_posix_acl_default - legacy xattr handler for default POSIX ACLs
*
* This is the legacy POSIX ACL default xattr handler. It is used by some
* filesystems to implement their ->listxattr() inode operation. New code
* should never use them.
*/
const struct xattr_handler nop_posix_acl_default = {
.name = XATTR_NAME_POSIX_ACL_DEFAULT,
.list = posix_acl_xattr_list,
};
EXPORT_SYMBOL_GPL(nop_posix_acl_default);
int simple_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
struct posix_acl *acl, int type)
{
int error;
struct inode *inode = d_inode(dentry);
if (type == ACL_TYPE_ACCESS) {
error = posix_acl_update_mode(idmap, inode,
&inode->i_mode, &acl);
if (error)
return error;
}
inode_set_ctime_current(inode);
if (IS_I_VERSION(inode))
inode_inc_iversion(inode);
set_cached_acl(inode, type, acl);
return 0;
}
int simple_acl_create(struct inode *dir, struct inode *inode)
{
struct posix_acl *default_acl, *acl;
int error;
error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
if (error)
return error;
set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
if (default_acl)
posix_acl_release(default_acl);
if (acl)
posix_acl_release(acl);
return 0;
}
static int vfs_set_acl_idmapped_mnt(struct mnt_idmap *idmap,
struct user_namespace *fs_userns,
struct posix_acl *acl)
{
for (int n = 0; n < acl->a_count; n++) {
struct posix_acl_entry *acl_e = &acl->a_entries[n];
switch (acl_e->e_tag) {
case ACL_USER:
acl_e->e_uid = from_vfsuid(idmap, fs_userns,
VFSUIDT_INIT(acl_e->e_uid));
break;
case ACL_GROUP:
acl_e->e_gid = from_vfsgid(idmap, fs_userns,
VFSGIDT_INIT(acl_e->e_gid));
break;
}
}
return 0;
}
/**
* vfs_set_acl - set posix acls
* @idmap: idmap of the mount
* @dentry: the dentry based on which to set the posix acls
* @acl_name: the name of the posix acl
* @kacl: the posix acls in the appropriate VFS format
*
* This function sets @kacl. The caller must all posix_acl_release() on @kacl
* afterwards.
*
* Return: On success 0, on error negative errno.
*/
int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
const char *acl_name, struct posix_acl *kacl)
{
int acl_type;
int error;
struct inode *inode = d_inode(dentry);
struct inode *delegated_inode = NULL;
acl_type = posix_acl_type(acl_name);
if (acl_type < 0)
return -EINVAL;
if (kacl) {
/*
* If we're on an idmapped mount translate from mount specific
* vfs{g,u}id_t into global filesystem k{g,u}id_t.
* Afterwards we can cache the POSIX ACLs filesystem wide and -
* if this is a filesystem with a backing store - ultimately
* translate them to backing store values.
*/
error = vfs_set_acl_idmapped_mnt(idmap, i_user_ns(inode), kacl);
if (error)
return error;
}
retry_deleg:
inode_lock(inode);
/*
* We only care about restrictions the inode struct itself places upon
* us otherwise POSIX ACLs aren't subject to any VFS restrictions.
*/
error = may_write_xattr(idmap, inode);
if (error)
goto out_inode_unlock;
error = security_inode_set_acl(idmap, dentry, acl_name, kacl);
if (error)
goto out_inode_unlock;
error = try_break_deleg(inode, &delegated_inode);
if (error)
goto out_inode_unlock;
if (likely(!is_bad_inode(inode)))
error = set_posix_acl(idmap, dentry, acl_type, kacl);
else
error = -EIO;
if (!error) {
fsnotify_xattr(dentry);
evm_inode_post_set_acl(dentry, acl_name, kacl);
}
out_inode_unlock:
inode_unlock(inode);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
return error;
}
EXPORT_SYMBOL_GPL(vfs_set_acl);
/**
* vfs_get_acl - get posix acls
* @idmap: idmap of the mount
* @dentry: the dentry based on which to retrieve the posix acls
* @acl_name: the name of the posix acl
*
* This function retrieves @kacl from the filesystem. The caller must all
* posix_acl_release() on @kacl.
*
* Return: On success POSIX ACLs in VFS format, on error negative errno.
*/
struct posix_acl *vfs_get_acl(struct mnt_idmap *idmap,
struct dentry *dentry, const char *acl_name)
{
struct inode *inode = d_inode(dentry);
struct posix_acl *acl;
int acl_type, error;
acl_type = posix_acl_type(acl_name);
if (acl_type < 0)
return ERR_PTR(-EINVAL);
/*
* The VFS has no restrictions on reading POSIX ACLs so calling
* something like xattr_permission() isn't needed. Only LSMs get a say.
*/
error = security_inode_get_acl(idmap, dentry, acl_name);
if (error)
return ERR_PTR(error);
if (!IS_POSIXACL(inode))
return ERR_PTR(-EOPNOTSUPP);
if (S_ISLNK(inode->i_mode))
return ERR_PTR(-EOPNOTSUPP);
acl = __get_acl(idmap, dentry, inode, acl_type);
if (IS_ERR(acl))
return acl;
if (!acl)
return ERR_PTR(-ENODATA);
return acl;
}
EXPORT_SYMBOL_GPL(vfs_get_acl);
/**
* vfs_remove_acl - remove posix acls
* @idmap: idmap of the mount
* @dentry: the dentry based on which to retrieve the posix acls
* @acl_name: the name of the posix acl
*
* This function removes posix acls.
*
* Return: On success 0, on error negative errno.
*/
int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
const char *acl_name)
{
int acl_type;
int error;
struct inode *inode = d_inode(dentry);
struct inode *delegated_inode = NULL;
acl_type = posix_acl_type(acl_name);
if (acl_type < 0)
return -EINVAL;
retry_deleg:
inode_lock(inode);
/*
* We only care about restrictions the inode struct itself places upon
* us otherwise POSIX ACLs aren't subject to any VFS restrictions.
*/
error = may_write_xattr(idmap, inode);
if (error)
goto out_inode_unlock;
error = security_inode_remove_acl(idmap, dentry, acl_name);
if (error)
goto out_inode_unlock;
error = try_break_deleg(inode, &delegated_inode);
if (error)
goto out_inode_unlock;
if (likely(!is_bad_inode(inode)))
error = set_posix_acl(idmap, dentry, acl_type, NULL);
else
error = -EIO;
if (!error) {
fsnotify_xattr(dentry);
evm_inode_post_remove_acl(idmap, dentry, acl_name);
}
out_inode_unlock:
inode_unlock(inode);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
return error;
}
EXPORT_SYMBOL_GPL(vfs_remove_acl);
int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
const char *acl_name, const void *kvalue, size_t size)
{
int error;
struct posix_acl *acl = NULL;
if (size) {
/*
* Note that posix_acl_from_xattr() uses GFP_NOFS when it
* probably doesn't need to here.
*/
acl = posix_acl_from_xattr(current_user_ns(), kvalue, size);
if (IS_ERR(acl))
return PTR_ERR(acl);
}
error = vfs_set_acl(idmap, dentry, acl_name, acl);
posix_acl_release(acl);
return error;
}
ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
const char *acl_name, void *kvalue, size_t size)
{
ssize_t error;
struct posix_acl *acl;
acl = vfs_get_acl(idmap, dentry, acl_name);
if (IS_ERR(acl))
return PTR_ERR(acl);
error = vfs_posix_acl_to_xattr(idmap, d_inode(dentry),
acl, kvalue, size);
posix_acl_release(acl);
return error;
}
| linux-master | fs/posix_acl.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/direct-io.c
*
* Copyright (C) 2002, Linus Torvalds.
*
* O_DIRECT
*
* 04Jul2002 Andrew Morton
* Initial version
* 11Sep2002 [email protected]
* added readv/writev support.
* 29Oct2002 Andrew Morton
* rewrote bio_add_page() support.
* 30Oct2002 [email protected]
* added support for non-aligned IO.
* 06Nov2002 [email protected]
* added asynchronous IO support.
* 21Jul2003 [email protected]
* added IO completion notifier.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/bio.h>
#include <linux/wait.h>
#include <linux/err.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/rwsem.h>
#include <linux/uio.h>
#include <linux/atomic.h>
#include <linux/prefetch.h>
#include "internal.h"
/*
* How many user pages to map in one call to iov_iter_extract_pages(). This
* determines the size of a structure in the slab cache
*/
#define DIO_PAGES 64
/*
* Flags for dio_complete()
*/
#define DIO_COMPLETE_ASYNC 0x01 /* This is async IO */
#define DIO_COMPLETE_INVALIDATE 0x02 /* Can invalidate pages */
/*
* This code generally works in units of "dio_blocks". A dio_block is
* somewhere between the hard sector size and the filesystem block size. it
* is determined on a per-invocation basis. When talking to the filesystem
* we need to convert dio_blocks to fs_blocks by scaling the dio_block quantity
* down by dio->blkfactor. Similarly, fs-blocksize quantities are converted
* to bio_block quantities by shifting left by blkfactor.
*
* If blkfactor is zero then the user's request was aligned to the filesystem's
* blocksize.
*/
/* dio_state only used in the submission path */
struct dio_submit {
struct bio *bio; /* bio under assembly */
unsigned blkbits; /* doesn't change */
unsigned blkfactor; /* When we're using an alignment which
is finer than the filesystem's soft
blocksize, this specifies how much
finer. blkfactor=2 means 1/4-block
alignment. Does not change */
unsigned start_zero_done; /* flag: sub-blocksize zeroing has
been performed at the start of a
write */
int pages_in_io; /* approximate total IO pages */
sector_t block_in_file; /* Current offset into the underlying
file in dio_block units. */
unsigned blocks_available; /* At block_in_file. changes */
int reap_counter; /* rate limit reaping */
sector_t final_block_in_request;/* doesn't change */
int boundary; /* prev block is at a boundary */
get_block_t *get_block; /* block mapping function */
loff_t logical_offset_in_bio; /* current first logical block in bio */
sector_t final_block_in_bio; /* current final block in bio + 1 */
sector_t next_block_for_io; /* next block to be put under IO,
in dio_blocks units */
/*
* Deferred addition of a page to the dio. These variables are
* private to dio_send_cur_page(), submit_page_section() and
* dio_bio_add_page().
*/
struct page *cur_page; /* The page */
unsigned cur_page_offset; /* Offset into it, in bytes */
unsigned cur_page_len; /* Nr of bytes at cur_page_offset */
sector_t cur_page_block; /* Where it starts */
loff_t cur_page_fs_offset; /* Offset in file */
struct iov_iter *iter;
/*
* Page queue. These variables belong to dio_refill_pages() and
* dio_get_page().
*/
unsigned head; /* next page to process */
unsigned tail; /* last valid page + 1 */
size_t from, to;
};
/* dio_state communicated between submission path and end_io */
struct dio {
int flags; /* doesn't change */
blk_opf_t opf; /* request operation type and flags */
struct gendisk *bio_disk;
struct inode *inode;
loff_t i_size; /* i_size when submitted */
dio_iodone_t *end_io; /* IO completion function */
bool is_pinned; /* T if we have pins on the pages */
void *private; /* copy from map_bh.b_private */
/* BIO completion state */
spinlock_t bio_lock; /* protects BIO fields below */
int page_errors; /* err from iov_iter_extract_pages() */
int is_async; /* is IO async ? */
bool defer_completion; /* defer AIO completion to workqueue? */
bool should_dirty; /* if pages should be dirtied */
int io_error; /* IO error in completion path */
unsigned long refcount; /* direct_io_worker() and bios */
struct bio *bio_list; /* singly linked via bi_private */
struct task_struct *waiter; /* waiting task (NULL if none) */
/* AIO related stuff */
struct kiocb *iocb; /* kiocb */
ssize_t result; /* IO result */
/*
* pages[] (and any fields placed after it) are not zeroed out at
* allocation time. Don't add new fields after pages[] unless you
* wish that they not be zeroed.
*/
union {
struct page *pages[DIO_PAGES]; /* page buffer */
struct work_struct complete_work;/* deferred AIO completion */
};
} ____cacheline_aligned_in_smp;
static struct kmem_cache *dio_cache __read_mostly;
/*
* How many pages are in the queue?
*/
static inline unsigned dio_pages_present(struct dio_submit *sdio)
{
return sdio->tail - sdio->head;
}
/*
* Go grab and pin some userspace pages. Typically we'll get 64 at a time.
*/
static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio)
{
struct page **pages = dio->pages;
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
ssize_t ret;
ret = iov_iter_extract_pages(sdio->iter, &pages, LONG_MAX,
DIO_PAGES, 0, &sdio->from);
if (ret < 0 && sdio->blocks_available && dio_op == REQ_OP_WRITE) {
/*
* A memory fault, but the filesystem has some outstanding
* mapped blocks. We need to use those blocks up to avoid
* leaking stale data in the file.
*/
if (dio->page_errors == 0)
dio->page_errors = ret;
dio->pages[0] = ZERO_PAGE(0);
sdio->head = 0;
sdio->tail = 1;
sdio->from = 0;
sdio->to = PAGE_SIZE;
return 0;
}
if (ret >= 0) {
ret += sdio->from;
sdio->head = 0;
sdio->tail = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
sdio->to = ((ret - 1) & (PAGE_SIZE - 1)) + 1;
return 0;
}
return ret;
}
/*
* Get another userspace page. Returns an ERR_PTR on error. Pages are
* buffered inside the dio so that we can call iov_iter_extract_pages()
* against a decent number of pages, less frequently. To provide nicer use of
* the L1 cache.
*/
static inline struct page *dio_get_page(struct dio *dio,
struct dio_submit *sdio)
{
if (dio_pages_present(sdio) == 0) {
int ret;
ret = dio_refill_pages(dio, sdio);
if (ret)
return ERR_PTR(ret);
BUG_ON(dio_pages_present(sdio) == 0);
}
return dio->pages[sdio->head];
}
static void dio_pin_page(struct dio *dio, struct page *page)
{
if (dio->is_pinned)
folio_add_pin(page_folio(page));
}
static void dio_unpin_page(struct dio *dio, struct page *page)
{
if (dio->is_pinned)
unpin_user_page(page);
}
/*
* dio_complete() - called when all DIO BIO I/O has been completed
*
* This drops i_dio_count, lets interested parties know that a DIO operation
* has completed, and calculates the resulting return code for the operation.
*
* It lets the filesystem know if it registered an interest earlier via
* get_block. Pass the private field of the map buffer_head so that
* filesystems can use it to hold additional state between get_block calls and
* dio_complete.
*/
static ssize_t dio_complete(struct dio *dio, ssize_t ret, unsigned int flags)
{
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
loff_t offset = dio->iocb->ki_pos;
ssize_t transferred = 0;
int err;
/*
* AIO submission can race with bio completion to get here while
* expecting to have the last io completed by bio completion.
* In that case -EIOCBQUEUED is in fact not an error we want
* to preserve through this call.
*/
if (ret == -EIOCBQUEUED)
ret = 0;
if (dio->result) {
transferred = dio->result;
/* Check for short read case */
if (dio_op == REQ_OP_READ &&
((offset + transferred) > dio->i_size))
transferred = dio->i_size - offset;
/* ignore EFAULT if some IO has been done */
if (unlikely(ret == -EFAULT) && transferred)
ret = 0;
}
if (ret == 0)
ret = dio->page_errors;
if (ret == 0)
ret = dio->io_error;
if (ret == 0)
ret = transferred;
if (dio->end_io) {
// XXX: ki_pos??
err = dio->end_io(dio->iocb, offset, ret, dio->private);
if (err)
ret = err;
}
/*
* Try again to invalidate clean pages which might have been cached by
* non-direct readahead, or faulted in by get_user_pages() if the source
* of the write was an mmap'ed region of the file we're writing. Either
* one is a pretty crazy thing to do, so we don't support it 100%. If
* this invalidation fails, tough, the write still worked...
*
* And this page cache invalidation has to be after dio->end_io(), as
* some filesystems convert unwritten extents to real allocations in
* end_io() when necessary, otherwise a racing buffer read would cache
* zeros from unwritten extents.
*/
if (flags & DIO_COMPLETE_INVALIDATE &&
ret > 0 && dio_op == REQ_OP_WRITE)
kiocb_invalidate_post_direct_write(dio->iocb, ret);
inode_dio_end(dio->inode);
if (flags & DIO_COMPLETE_ASYNC) {
/*
* generic_write_sync expects ki_pos to have been updated
* already, but the submission path only does this for
* synchronous I/O.
*/
dio->iocb->ki_pos += transferred;
if (ret > 0 && dio_op == REQ_OP_WRITE)
ret = generic_write_sync(dio->iocb, ret);
dio->iocb->ki_complete(dio->iocb, ret);
}
kmem_cache_free(dio_cache, dio);
return ret;
}
static void dio_aio_complete_work(struct work_struct *work)
{
struct dio *dio = container_of(work, struct dio, complete_work);
dio_complete(dio, 0, DIO_COMPLETE_ASYNC | DIO_COMPLETE_INVALIDATE);
}
static blk_status_t dio_bio_complete(struct dio *dio, struct bio *bio);
/*
* Asynchronous IO callback.
*/
static void dio_bio_end_aio(struct bio *bio)
{
struct dio *dio = bio->bi_private;
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
unsigned long remaining;
unsigned long flags;
bool defer_completion = false;
/* cleanup the bio */
dio_bio_complete(dio, bio);
spin_lock_irqsave(&dio->bio_lock, flags);
remaining = --dio->refcount;
if (remaining == 1 && dio->waiter)
wake_up_process(dio->waiter);
spin_unlock_irqrestore(&dio->bio_lock, flags);
if (remaining == 0) {
/*
* Defer completion when defer_completion is set or
* when the inode has pages mapped and this is AIO write.
* We need to invalidate those pages because there is a
* chance they contain stale data in the case buffered IO
* went in between AIO submission and completion into the
* same region.
*/
if (dio->result)
defer_completion = dio->defer_completion ||
(dio_op == REQ_OP_WRITE &&
dio->inode->i_mapping->nrpages);
if (defer_completion) {
INIT_WORK(&dio->complete_work, dio_aio_complete_work);
queue_work(dio->inode->i_sb->s_dio_done_wq,
&dio->complete_work);
} else {
dio_complete(dio, 0, DIO_COMPLETE_ASYNC);
}
}
}
/*
* The BIO completion handler simply queues the BIO up for the process-context
* handler.
*
* During I/O bi_private points at the dio. After I/O, bi_private is used to
* implement a singly-linked list of completed BIOs, at dio->bio_list.
*/
static void dio_bio_end_io(struct bio *bio)
{
struct dio *dio = bio->bi_private;
unsigned long flags;
spin_lock_irqsave(&dio->bio_lock, flags);
bio->bi_private = dio->bio_list;
dio->bio_list = bio;
if (--dio->refcount == 1 && dio->waiter)
wake_up_process(dio->waiter);
spin_unlock_irqrestore(&dio->bio_lock, flags);
}
static inline void
dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
struct block_device *bdev,
sector_t first_sector, int nr_vecs)
{
struct bio *bio;
/*
* bio_alloc() is guaranteed to return a bio when allowed to sleep and
* we request a valid number of vectors.
*/
bio = bio_alloc(bdev, nr_vecs, dio->opf, GFP_KERNEL);
bio->bi_iter.bi_sector = first_sector;
if (dio->is_async)
bio->bi_end_io = dio_bio_end_aio;
else
bio->bi_end_io = dio_bio_end_io;
if (dio->is_pinned)
bio_set_flag(bio, BIO_PAGE_PINNED);
sdio->bio = bio;
sdio->logical_offset_in_bio = sdio->cur_page_fs_offset;
}
/*
* In the AIO read case we speculatively dirty the pages before starting IO.
* During IO completion, any of these pages which happen to have been written
* back will be redirtied by bio_check_pages_dirty().
*
* bios hold a dio reference between submit_bio and ->end_io.
*/
static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
{
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
struct bio *bio = sdio->bio;
unsigned long flags;
bio->bi_private = dio;
spin_lock_irqsave(&dio->bio_lock, flags);
dio->refcount++;
spin_unlock_irqrestore(&dio->bio_lock, flags);
if (dio->is_async && dio_op == REQ_OP_READ && dio->should_dirty)
bio_set_pages_dirty(bio);
dio->bio_disk = bio->bi_bdev->bd_disk;
submit_bio(bio);
sdio->bio = NULL;
sdio->boundary = 0;
sdio->logical_offset_in_bio = 0;
}
/*
* Release any resources in case of a failure
*/
static inline void dio_cleanup(struct dio *dio, struct dio_submit *sdio)
{
if (dio->is_pinned)
unpin_user_pages(dio->pages + sdio->head,
sdio->tail - sdio->head);
sdio->head = sdio->tail;
}
/*
* Wait for the next BIO to complete. Remove it and return it. NULL is
* returned once all BIOs have been completed. This must only be called once
* all bios have been issued so that dio->refcount can only decrease. This
* requires that the caller hold a reference on the dio.
*/
static struct bio *dio_await_one(struct dio *dio)
{
unsigned long flags;
struct bio *bio = NULL;
spin_lock_irqsave(&dio->bio_lock, flags);
/*
* Wait as long as the list is empty and there are bios in flight. bio
* completion drops the count, maybe adds to the list, and wakes while
* holding the bio_lock so we don't need set_current_state()'s barrier
* and can call it after testing our condition.
*/
while (dio->refcount > 1 && dio->bio_list == NULL) {
__set_current_state(TASK_UNINTERRUPTIBLE);
dio->waiter = current;
spin_unlock_irqrestore(&dio->bio_lock, flags);
blk_io_schedule();
/* wake up sets us TASK_RUNNING */
spin_lock_irqsave(&dio->bio_lock, flags);
dio->waiter = NULL;
}
if (dio->bio_list) {
bio = dio->bio_list;
dio->bio_list = bio->bi_private;
}
spin_unlock_irqrestore(&dio->bio_lock, flags);
return bio;
}
/*
* Process one completed BIO. No locks are held.
*/
static blk_status_t dio_bio_complete(struct dio *dio, struct bio *bio)
{
blk_status_t err = bio->bi_status;
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
bool should_dirty = dio_op == REQ_OP_READ && dio->should_dirty;
if (err) {
if (err == BLK_STS_AGAIN && (bio->bi_opf & REQ_NOWAIT))
dio->io_error = -EAGAIN;
else
dio->io_error = -EIO;
}
if (dio->is_async && should_dirty) {
bio_check_pages_dirty(bio); /* transfers ownership */
} else {
bio_release_pages(bio, should_dirty);
bio_put(bio);
}
return err;
}
/*
* Wait on and process all in-flight BIOs. This must only be called once
* all bios have been issued so that the refcount can only decrease.
* This just waits for all bios to make it through dio_bio_complete. IO
* errors are propagated through dio->io_error and should be propagated via
* dio_complete().
*/
static void dio_await_completion(struct dio *dio)
{
struct bio *bio;
do {
bio = dio_await_one(dio);
if (bio)
dio_bio_complete(dio, bio);
} while (bio);
}
/*
* A really large O_DIRECT read or write can generate a lot of BIOs. So
* to keep the memory consumption sane we periodically reap any completed BIOs
* during the BIO generation phase.
*
* This also helps to limit the peak amount of pinned userspace memory.
*/
static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio)
{
int ret = 0;
if (sdio->reap_counter++ >= 64) {
while (dio->bio_list) {
unsigned long flags;
struct bio *bio;
int ret2;
spin_lock_irqsave(&dio->bio_lock, flags);
bio = dio->bio_list;
dio->bio_list = bio->bi_private;
spin_unlock_irqrestore(&dio->bio_lock, flags);
ret2 = blk_status_to_errno(dio_bio_complete(dio, bio));
if (ret == 0)
ret = ret2;
}
sdio->reap_counter = 0;
}
return ret;
}
static int dio_set_defer_completion(struct dio *dio)
{
struct super_block *sb = dio->inode->i_sb;
if (dio->defer_completion)
return 0;
dio->defer_completion = true;
if (!sb->s_dio_done_wq)
return sb_init_dio_done_wq(sb);
return 0;
}
/*
* Call into the fs to map some more disk blocks. We record the current number
* of available blocks at sdio->blocks_available. These are in units of the
* fs blocksize, i_blocksize(inode).
*
* The fs is allowed to map lots of blocks at once. If it wants to do that,
* it uses the passed inode-relative block number as the file offset, as usual.
*
* get_block() is passed the number of i_blkbits-sized blocks which direct_io
* has remaining to do. The fs should not map more than this number of blocks.
*
* If the fs has mapped a lot of blocks, it should populate bh->b_size to
* indicate how much contiguous disk space has been made available at
* bh->b_blocknr.
*
* If *any* of the mapped blocks are new, then the fs must set buffer_new().
* This isn't very efficient...
*
* In the case of filesystem holes: the fs may return an arbitrarily-large
* hole by returning an appropriate value in b_size and by clearing
* buffer_mapped(). However the direct-io code will only process holes one
* block at a time - it will repeatedly call get_block() as it walks the hole.
*/
static int get_more_blocks(struct dio *dio, struct dio_submit *sdio,
struct buffer_head *map_bh)
{
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
int ret;
sector_t fs_startblk; /* Into file, in filesystem-sized blocks */
sector_t fs_endblk; /* Into file, in filesystem-sized blocks */
unsigned long fs_count; /* Number of filesystem-sized blocks */
int create;
unsigned int i_blkbits = sdio->blkbits + sdio->blkfactor;
loff_t i_size;
/*
* If there was a memory error and we've overwritten all the
* mapped blocks then we can now return that memory error
*/
ret = dio->page_errors;
if (ret == 0) {
BUG_ON(sdio->block_in_file >= sdio->final_block_in_request);
fs_startblk = sdio->block_in_file >> sdio->blkfactor;
fs_endblk = (sdio->final_block_in_request - 1) >>
sdio->blkfactor;
fs_count = fs_endblk - fs_startblk + 1;
map_bh->b_state = 0;
map_bh->b_size = fs_count << i_blkbits;
/*
* For writes that could fill holes inside i_size on a
* DIO_SKIP_HOLES filesystem we forbid block creations: only
* overwrites are permitted. We will return early to the caller
* once we see an unmapped buffer head returned, and the caller
* will fall back to buffered I/O.
*
* Otherwise the decision is left to the get_blocks method,
* which may decide to handle it or also return an unmapped
* buffer head.
*/
create = dio_op == REQ_OP_WRITE;
if (dio->flags & DIO_SKIP_HOLES) {
i_size = i_size_read(dio->inode);
if (i_size && fs_startblk <= (i_size - 1) >> i_blkbits)
create = 0;
}
ret = (*sdio->get_block)(dio->inode, fs_startblk,
map_bh, create);
/* Store for completion */
dio->private = map_bh->b_private;
if (ret == 0 && buffer_defer_completion(map_bh))
ret = dio_set_defer_completion(dio);
}
return ret;
}
/*
* There is no bio. Make one now.
*/
static inline int dio_new_bio(struct dio *dio, struct dio_submit *sdio,
sector_t start_sector, struct buffer_head *map_bh)
{
sector_t sector;
int ret, nr_pages;
ret = dio_bio_reap(dio, sdio);
if (ret)
goto out;
sector = start_sector << (sdio->blkbits - 9);
nr_pages = bio_max_segs(sdio->pages_in_io);
BUG_ON(nr_pages <= 0);
dio_bio_alloc(dio, sdio, map_bh->b_bdev, sector, nr_pages);
sdio->boundary = 0;
out:
return ret;
}
/*
* Attempt to put the current chunk of 'cur_page' into the current BIO. If
* that was successful then update final_block_in_bio and take a ref against
* the just-added page.
*
* Return zero on success. Non-zero means the caller needs to start a new BIO.
*/
static inline int dio_bio_add_page(struct dio *dio, struct dio_submit *sdio)
{
int ret;
ret = bio_add_page(sdio->bio, sdio->cur_page,
sdio->cur_page_len, sdio->cur_page_offset);
if (ret == sdio->cur_page_len) {
/*
* Decrement count only, if we are done with this page
*/
if ((sdio->cur_page_len + sdio->cur_page_offset) == PAGE_SIZE)
sdio->pages_in_io--;
dio_pin_page(dio, sdio->cur_page);
sdio->final_block_in_bio = sdio->cur_page_block +
(sdio->cur_page_len >> sdio->blkbits);
ret = 0;
} else {
ret = 1;
}
return ret;
}
/*
* Put cur_page under IO. The section of cur_page which is described by
* cur_page_offset,cur_page_len is put into a BIO. The section of cur_page
* starts on-disk at cur_page_block.
*
* We take a ref against the page here (on behalf of its presence in the bio).
*
* The caller of this function is responsible for removing cur_page from the
* dio, and for dropping the refcount which came from that presence.
*/
static inline int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio,
struct buffer_head *map_bh)
{
int ret = 0;
if (sdio->bio) {
loff_t cur_offset = sdio->cur_page_fs_offset;
loff_t bio_next_offset = sdio->logical_offset_in_bio +
sdio->bio->bi_iter.bi_size;
/*
* See whether this new request is contiguous with the old.
*
* Btrfs cannot handle having logically non-contiguous requests
* submitted. For example if you have
*
* Logical: [0-4095][HOLE][8192-12287]
* Physical: [0-4095] [4096-8191]
*
* We cannot submit those pages together as one BIO. So if our
* current logical offset in the file does not equal what would
* be the next logical offset in the bio, submit the bio we
* have.
*/
if (sdio->final_block_in_bio != sdio->cur_page_block ||
cur_offset != bio_next_offset)
dio_bio_submit(dio, sdio);
}
if (sdio->bio == NULL) {
ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh);
if (ret)
goto out;
}
if (dio_bio_add_page(dio, sdio) != 0) {
dio_bio_submit(dio, sdio);
ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh);
if (ret == 0) {
ret = dio_bio_add_page(dio, sdio);
BUG_ON(ret != 0);
}
}
out:
return ret;
}
/*
* An autonomous function to put a chunk of a page under deferred IO.
*
* The caller doesn't actually know (or care) whether this piece of page is in
* a BIO, or is under IO or whatever. We just take care of all possible
* situations here. The separation between the logic of do_direct_IO() and
* that of submit_page_section() is important for clarity. Please don't break.
*
* The chunk of page starts on-disk at blocknr.
*
* We perform deferred IO, by recording the last-submitted page inside our
* private part of the dio structure. If possible, we just expand the IO
* across that page here.
*
* If that doesn't work out then we put the old page into the bio and add this
* page to the dio instead.
*/
static inline int
submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page,
unsigned offset, unsigned len, sector_t blocknr,
struct buffer_head *map_bh)
{
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
int ret = 0;
int boundary = sdio->boundary; /* dio_send_cur_page may clear it */
if (dio_op == REQ_OP_WRITE) {
/*
* Read accounting is performed in submit_bio()
*/
task_io_account_write(len);
}
/*
* Can we just grow the current page's presence in the dio?
*/
if (sdio->cur_page == page &&
sdio->cur_page_offset + sdio->cur_page_len == offset &&
sdio->cur_page_block +
(sdio->cur_page_len >> sdio->blkbits) == blocknr) {
sdio->cur_page_len += len;
goto out;
}
/*
* If there's a deferred page already there then send it.
*/
if (sdio->cur_page) {
ret = dio_send_cur_page(dio, sdio, map_bh);
dio_unpin_page(dio, sdio->cur_page);
sdio->cur_page = NULL;
if (ret)
return ret;
}
dio_pin_page(dio, page); /* It is in dio */
sdio->cur_page = page;
sdio->cur_page_offset = offset;
sdio->cur_page_len = len;
sdio->cur_page_block = blocknr;
sdio->cur_page_fs_offset = sdio->block_in_file << sdio->blkbits;
out:
/*
* If boundary then we want to schedule the IO now to
* avoid metadata seeks.
*/
if (boundary) {
ret = dio_send_cur_page(dio, sdio, map_bh);
if (sdio->bio)
dio_bio_submit(dio, sdio);
dio_unpin_page(dio, sdio->cur_page);
sdio->cur_page = NULL;
}
return ret;
}
/*
* If we are not writing the entire block and get_block() allocated
* the block for us, we need to fill-in the unused portion of the
* block with zeros. This happens only if user-buffer, fileoffset or
* io length is not filesystem block-size multiple.
*
* `end' is zero if we're doing the start of the IO, 1 at the end of the
* IO.
*/
static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio,
int end, struct buffer_head *map_bh)
{
unsigned dio_blocks_per_fs_block;
unsigned this_chunk_blocks; /* In dio_blocks */
unsigned this_chunk_bytes;
struct page *page;
sdio->start_zero_done = 1;
if (!sdio->blkfactor || !buffer_new(map_bh))
return;
dio_blocks_per_fs_block = 1 << sdio->blkfactor;
this_chunk_blocks = sdio->block_in_file & (dio_blocks_per_fs_block - 1);
if (!this_chunk_blocks)
return;
/*
* We need to zero out part of an fs block. It is either at the
* beginning or the end of the fs block.
*/
if (end)
this_chunk_blocks = dio_blocks_per_fs_block - this_chunk_blocks;
this_chunk_bytes = this_chunk_blocks << sdio->blkbits;
page = ZERO_PAGE(0);
if (submit_page_section(dio, sdio, page, 0, this_chunk_bytes,
sdio->next_block_for_io, map_bh))
return;
sdio->next_block_for_io += this_chunk_blocks;
}
/*
* Walk the user pages, and the file, mapping blocks to disk and generating
* a sequence of (page,offset,len,block) mappings. These mappings are injected
* into submit_page_section(), which takes care of the next stage of submission
*
* Direct IO against a blockdev is different from a file. Because we can
* happily perform page-sized but 512-byte aligned IOs. It is important that
* blockdev IO be able to have fine alignment and large sizes.
*
* So what we do is to permit the ->get_block function to populate bh.b_size
* with the size of IO which is permitted at this offset and this i_blkbits.
*
* For best results, the blockdev should be set up with 512-byte i_blkbits and
* it should set b_size to PAGE_SIZE or more inside get_block(). This gives
* fine alignment but still allows this function to work in PAGE_SIZE units.
*/
static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
struct buffer_head *map_bh)
{
const enum req_op dio_op = dio->opf & REQ_OP_MASK;
const unsigned blkbits = sdio->blkbits;
const unsigned i_blkbits = blkbits + sdio->blkfactor;
int ret = 0;
while (sdio->block_in_file < sdio->final_block_in_request) {
struct page *page;
size_t from, to;
page = dio_get_page(dio, sdio);
if (IS_ERR(page)) {
ret = PTR_ERR(page);
goto out;
}
from = sdio->head ? 0 : sdio->from;
to = (sdio->head == sdio->tail - 1) ? sdio->to : PAGE_SIZE;
sdio->head++;
while (from < to) {
unsigned this_chunk_bytes; /* # of bytes mapped */
unsigned this_chunk_blocks; /* # of blocks */
unsigned u;
if (sdio->blocks_available == 0) {
/*
* Need to go and map some more disk
*/
unsigned long blkmask;
unsigned long dio_remainder;
ret = get_more_blocks(dio, sdio, map_bh);
if (ret) {
dio_unpin_page(dio, page);
goto out;
}
if (!buffer_mapped(map_bh))
goto do_holes;
sdio->blocks_available =
map_bh->b_size >> blkbits;
sdio->next_block_for_io =
map_bh->b_blocknr << sdio->blkfactor;
if (buffer_new(map_bh)) {
clean_bdev_aliases(
map_bh->b_bdev,
map_bh->b_blocknr,
map_bh->b_size >> i_blkbits);
}
if (!sdio->blkfactor)
goto do_holes;
blkmask = (1 << sdio->blkfactor) - 1;
dio_remainder = (sdio->block_in_file & blkmask);
/*
* If we are at the start of IO and that IO
* starts partway into a fs-block,
* dio_remainder will be non-zero. If the IO
* is a read then we can simply advance the IO
* cursor to the first block which is to be
* read. But if the IO is a write and the
* block was newly allocated we cannot do that;
* the start of the fs block must be zeroed out
* on-disk
*/
if (!buffer_new(map_bh))
sdio->next_block_for_io += dio_remainder;
sdio->blocks_available -= dio_remainder;
}
do_holes:
/* Handle holes */
if (!buffer_mapped(map_bh)) {
loff_t i_size_aligned;
/* AKPM: eargh, -ENOTBLK is a hack */
if (dio_op == REQ_OP_WRITE) {
dio_unpin_page(dio, page);
return -ENOTBLK;
}
/*
* Be sure to account for a partial block as the
* last block in the file
*/
i_size_aligned = ALIGN(i_size_read(dio->inode),
1 << blkbits);
if (sdio->block_in_file >=
i_size_aligned >> blkbits) {
/* We hit eof */
dio_unpin_page(dio, page);
goto out;
}
zero_user(page, from, 1 << blkbits);
sdio->block_in_file++;
from += 1 << blkbits;
dio->result += 1 << blkbits;
goto next_block;
}
/*
* If we're performing IO which has an alignment which
* is finer than the underlying fs, go check to see if
* we must zero out the start of this block.
*/
if (unlikely(sdio->blkfactor && !sdio->start_zero_done))
dio_zero_block(dio, sdio, 0, map_bh);
/*
* Work out, in this_chunk_blocks, how much disk we
* can add to this page
*/
this_chunk_blocks = sdio->blocks_available;
u = (to - from) >> blkbits;
if (this_chunk_blocks > u)
this_chunk_blocks = u;
u = sdio->final_block_in_request - sdio->block_in_file;
if (this_chunk_blocks > u)
this_chunk_blocks = u;
this_chunk_bytes = this_chunk_blocks << blkbits;
BUG_ON(this_chunk_bytes == 0);
if (this_chunk_blocks == sdio->blocks_available)
sdio->boundary = buffer_boundary(map_bh);
ret = submit_page_section(dio, sdio, page,
from,
this_chunk_bytes,
sdio->next_block_for_io,
map_bh);
if (ret) {
dio_unpin_page(dio, page);
goto out;
}
sdio->next_block_for_io += this_chunk_blocks;
sdio->block_in_file += this_chunk_blocks;
from += this_chunk_bytes;
dio->result += this_chunk_bytes;
sdio->blocks_available -= this_chunk_blocks;
next_block:
BUG_ON(sdio->block_in_file > sdio->final_block_in_request);
if (sdio->block_in_file == sdio->final_block_in_request)
break;
}
/* Drop the pin which was taken in get_user_pages() */
dio_unpin_page(dio, page);
}
out:
return ret;
}
static inline int drop_refcount(struct dio *dio)
{
int ret2;
unsigned long flags;
/*
* Sync will always be dropping the final ref and completing the
* operation. AIO can if it was a broken operation described above or
* in fact if all the bios race to complete before we get here. In
* that case dio_complete() translates the EIOCBQUEUED into the proper
* return code that the caller will hand to ->complete().
*
* This is managed by the bio_lock instead of being an atomic_t so that
* completion paths can drop their ref and use the remaining count to
* decide to wake the submission path atomically.
*/
spin_lock_irqsave(&dio->bio_lock, flags);
ret2 = --dio->refcount;
spin_unlock_irqrestore(&dio->bio_lock, flags);
return ret2;
}
/*
* This is a library function for use by filesystem drivers.
*
* The locking rules are governed by the flags parameter:
* - if the flags value contains DIO_LOCKING we use a fancy locking
* scheme for dumb filesystems.
* For writes this function is called under i_mutex and returns with
* i_mutex held, for reads, i_mutex is not held on entry, but it is
* taken and dropped again before returning.
* - if the flags value does NOT contain DIO_LOCKING we don't use any
* internal locking but rather rely on the filesystem to synchronize
* direct I/O reads/writes versus each other and truncate.
*
* To help with locking against truncate we incremented the i_dio_count
* counter before starting direct I/O, and decrement it once we are done.
* Truncate can wait for it to reach zero to provide exclusion. It is
* expected that filesystem provide exclusion between new direct I/O
* and truncates. For DIO_LOCKING filesystems this is done by i_mutex,
* but other filesystems need to take care of this on their own.
*
* NOTE: if you pass "sdio" to anything by pointer make sure that function
* is always inlined. Otherwise gcc is unable to split the structure into
* individual fields and will generate much worse code. This is important
* for the whole file.
*/
ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
struct block_device *bdev, struct iov_iter *iter,
get_block_t get_block, dio_iodone_t end_io,
int flags)
{
unsigned i_blkbits = READ_ONCE(inode->i_blkbits);
unsigned blkbits = i_blkbits;
unsigned blocksize_mask = (1 << blkbits) - 1;
ssize_t retval = -EINVAL;
const size_t count = iov_iter_count(iter);
loff_t offset = iocb->ki_pos;
const loff_t end = offset + count;
struct dio *dio;
struct dio_submit sdio = { 0, };
struct buffer_head map_bh = { 0, };
struct blk_plug plug;
unsigned long align = offset | iov_iter_alignment(iter);
/*
* Avoid references to bdev if not absolutely needed to give
* the early prefetch in the caller enough time.
*/
/* watch out for a 0 len io from a tricksy fs */
if (iov_iter_rw(iter) == READ && !count)
return 0;
dio = kmem_cache_alloc(dio_cache, GFP_KERNEL);
if (!dio)
return -ENOMEM;
/*
* Believe it or not, zeroing out the page array caused a .5%
* performance regression in a database benchmark. So, we take
* care to only zero out what's needed.
*/
memset(dio, 0, offsetof(struct dio, pages));
dio->flags = flags;
if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) {
/* will be released by direct_io_worker */
inode_lock(inode);
}
dio->is_pinned = iov_iter_extract_will_pin(iter);
/* Once we sampled i_size check for reads beyond EOF */
dio->i_size = i_size_read(inode);
if (iov_iter_rw(iter) == READ && offset >= dio->i_size) {
retval = 0;
goto fail_dio;
}
if (align & blocksize_mask) {
if (bdev)
blkbits = blksize_bits(bdev_logical_block_size(bdev));
blocksize_mask = (1 << blkbits) - 1;
if (align & blocksize_mask)
goto fail_dio;
}
if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) {
struct address_space *mapping = iocb->ki_filp->f_mapping;
retval = filemap_write_and_wait_range(mapping, offset, end - 1);
if (retval)
goto fail_dio;
}
/*
* For file extending writes updating i_size before data writeouts
* complete can expose uninitialized blocks in dumb filesystems.
* In that case we need to wait for I/O completion even if asked
* for an asynchronous write.
*/
if (is_sync_kiocb(iocb))
dio->is_async = false;
else if (iov_iter_rw(iter) == WRITE && end > i_size_read(inode))
dio->is_async = false;
else
dio->is_async = true;
dio->inode = inode;
if (iov_iter_rw(iter) == WRITE) {
dio->opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
if (iocb->ki_flags & IOCB_NOWAIT)
dio->opf |= REQ_NOWAIT;
} else {
dio->opf = REQ_OP_READ;
}
/*
* For AIO O_(D)SYNC writes we need to defer completions to a workqueue
* so that we can call ->fsync.
*/
if (dio->is_async && iov_iter_rw(iter) == WRITE) {
retval = 0;
if (iocb_is_dsync(iocb))
retval = dio_set_defer_completion(dio);
else if (!dio->inode->i_sb->s_dio_done_wq) {
/*
* In case of AIO write racing with buffered read we
* need to defer completion. We can't decide this now,
* however the workqueue needs to be initialized here.
*/
retval = sb_init_dio_done_wq(dio->inode->i_sb);
}
if (retval)
goto fail_dio;
}
/*
* Will be decremented at I/O completion time.
*/
inode_dio_begin(inode);
retval = 0;
sdio.blkbits = blkbits;
sdio.blkfactor = i_blkbits - blkbits;
sdio.block_in_file = offset >> blkbits;
sdio.get_block = get_block;
dio->end_io = end_io;
sdio.final_block_in_bio = -1;
sdio.next_block_for_io = -1;
dio->iocb = iocb;
spin_lock_init(&dio->bio_lock);
dio->refcount = 1;
dio->should_dirty = user_backed_iter(iter) && iov_iter_rw(iter) == READ;
sdio.iter = iter;
sdio.final_block_in_request = end >> blkbits;
/*
* In case of non-aligned buffers, we may need 2 more
* pages since we need to zero out first and last block.
*/
if (unlikely(sdio.blkfactor))
sdio.pages_in_io = 2;
sdio.pages_in_io += iov_iter_npages(iter, INT_MAX);
blk_start_plug(&plug);
retval = do_direct_IO(dio, &sdio, &map_bh);
if (retval)
dio_cleanup(dio, &sdio);
if (retval == -ENOTBLK) {
/*
* The remaining part of the request will be
* handled by buffered I/O when we return
*/
retval = 0;
}
/*
* There may be some unwritten disk at the end of a part-written
* fs-block-sized block. Go zero that now.
*/
dio_zero_block(dio, &sdio, 1, &map_bh);
if (sdio.cur_page) {
ssize_t ret2;
ret2 = dio_send_cur_page(dio, &sdio, &map_bh);
if (retval == 0)
retval = ret2;
dio_unpin_page(dio, sdio.cur_page);
sdio.cur_page = NULL;
}
if (sdio.bio)
dio_bio_submit(dio, &sdio);
blk_finish_plug(&plug);
/*
* It is possible that, we return short IO due to end of file.
* In that case, we need to release all the pages we got hold on.
*/
dio_cleanup(dio, &sdio);
/*
* All block lookups have been performed. For READ requests
* we can let i_mutex go now that its achieved its purpose
* of protecting us from looking up uninitialized blocks.
*/
if (iov_iter_rw(iter) == READ && (dio->flags & DIO_LOCKING))
inode_unlock(dio->inode);
/*
* The only time we want to leave bios in flight is when a successful
* partial aio read or full aio write have been setup. In that case
* bio completion will call aio_complete. The only time it's safe to
* call aio_complete is when we return -EIOCBQUEUED, so we key on that.
* This had *better* be the only place that raises -EIOCBQUEUED.
*/
BUG_ON(retval == -EIOCBQUEUED);
if (dio->is_async && retval == 0 && dio->result &&
(iov_iter_rw(iter) == READ || dio->result == count))
retval = -EIOCBQUEUED;
else
dio_await_completion(dio);
if (drop_refcount(dio) == 0) {
retval = dio_complete(dio, retval, DIO_COMPLETE_INVALIDATE);
} else
BUG_ON(retval != -EIOCBQUEUED);
return retval;
fail_dio:
if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ)
inode_unlock(inode);
kmem_cache_free(dio_cache, dio);
return retval;
}
EXPORT_SYMBOL(__blockdev_direct_IO);
static __init int dio_init(void)
{
dio_cache = KMEM_CACHE(dio, SLAB_PANIC);
return 0;
}
module_init(dio_init)
| linux-master | fs/direct-io.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/stat.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/blkdev.h>
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/highuid.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/compat.h>
#include <linux/iversion.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include "internal.h"
#include "mount.h"
/**
* generic_fillattr - Fill in the basic attributes from the inode struct
* @idmap: idmap of the mount the inode was found from
* @request_mask: statx request_mask
* @inode: Inode to use as the source
* @stat: Where to fill in the attributes
*
* Fill in the basic attributes in the kstat structure from data that's to be
* found on the VFS inode structure. This is the default if no getattr inode
* operation is supplied.
*
* If the inode has been found through an idmapped mount the idmap of
* the vfsmount must be passed through @idmap. This function will then
* take care to map the inode according to @idmap before filling in the
* uid and gid filds. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply passs @nop_mnt_idmap.
*/
void generic_fillattr(struct mnt_idmap *idmap, u32 request_mask,
struct inode *inode, struct kstat *stat)
{
vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
stat->dev = inode->i_sb->s_dev;
stat->ino = inode->i_ino;
stat->mode = inode->i_mode;
stat->nlink = inode->i_nlink;
stat->uid = vfsuid_into_kuid(vfsuid);
stat->gid = vfsgid_into_kgid(vfsgid);
stat->rdev = inode->i_rdev;
stat->size = i_size_read(inode);
stat->atime = inode->i_atime;
stat->mtime = inode->i_mtime;
stat->ctime = inode_get_ctime(inode);
stat->blksize = i_blocksize(inode);
stat->blocks = inode->i_blocks;
if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) {
stat->result_mask |= STATX_CHANGE_COOKIE;
stat->change_cookie = inode_query_iversion(inode);
}
}
EXPORT_SYMBOL(generic_fillattr);
/**
* generic_fill_statx_attr - Fill in the statx attributes from the inode flags
* @inode: Inode to use as the source
* @stat: Where to fill in the attribute flags
*
* Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
* inode that are published on i_flags and enforced by the VFS.
*/
void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
{
if (inode->i_flags & S_IMMUTABLE)
stat->attributes |= STATX_ATTR_IMMUTABLE;
if (inode->i_flags & S_APPEND)
stat->attributes |= STATX_ATTR_APPEND;
stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
}
EXPORT_SYMBOL(generic_fill_statx_attr);
/**
* vfs_getattr_nosec - getattr without security checks
* @path: file to get attributes from
* @stat: structure to return attributes in
* @request_mask: STATX_xxx flags indicating what the caller wants
* @query_flags: Query mode (AT_STATX_SYNC_TYPE)
*
* Get attributes without calling security_inode_getattr.
*
* Currently the only caller other than vfs_getattr is internal to the
* filehandle lookup code, which uses only the inode number and returns no
* attributes to any user. Any other code probably wants vfs_getattr.
*/
int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
struct mnt_idmap *idmap;
struct inode *inode = d_backing_inode(path->dentry);
memset(stat, 0, sizeof(*stat));
stat->result_mask |= STATX_BASIC_STATS;
query_flags &= AT_STATX_SYNC_TYPE;
/* allow the fs to override these if it really wants to */
/* SB_NOATIME means filesystem supplies dummy atime value */
if (inode->i_sb->s_flags & SB_NOATIME)
stat->result_mask &= ~STATX_ATIME;
/*
* Note: If you add another clause to set an attribute flag, please
* update attributes_mask below.
*/
if (IS_AUTOMOUNT(inode))
stat->attributes |= STATX_ATTR_AUTOMOUNT;
if (IS_DAX(inode))
stat->attributes |= STATX_ATTR_DAX;
stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
STATX_ATTR_DAX);
idmap = mnt_idmap(path->mnt);
if (inode->i_op->getattr)
return inode->i_op->getattr(idmap, path, stat,
request_mask, query_flags);
generic_fillattr(idmap, request_mask, inode, stat);
return 0;
}
EXPORT_SYMBOL(vfs_getattr_nosec);
/*
* vfs_getattr - Get the enhanced basic attributes of a file
* @path: The file of interest
* @stat: Where to return the statistics
* @request_mask: STATX_xxx flags indicating what the caller wants
* @query_flags: Query mode (AT_STATX_SYNC_TYPE)
*
* Ask the filesystem for a file's attributes. The caller must indicate in
* request_mask and query_flags to indicate what they want.
*
* If the file is remote, the filesystem can be forced to update the attributes
* from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
* suppress the update by passing AT_STATX_DONT_SYNC.
*
* Bits must have been set in request_mask to indicate which attributes the
* caller wants retrieving. Any such attribute not requested may be returned
* anyway, but the value may be approximate, and, if remote, may not have been
* synchronised with the server.
*
* 0 will be returned on success, and a -ve error code if unsuccessful.
*/
int vfs_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
int retval;
retval = security_inode_getattr(path);
if (retval)
return retval;
return vfs_getattr_nosec(path, stat, request_mask, query_flags);
}
EXPORT_SYMBOL(vfs_getattr);
/**
* vfs_fstat - Get the basic attributes by file descriptor
* @fd: The file descriptor referring to the file of interest
* @stat: The result structure to fill in.
*
* This function is a wrapper around vfs_getattr(). The main difference is
* that it uses a file descriptor to determine the file location.
*
* 0 will be returned on success, and a -ve error code if unsuccessful.
*/
int vfs_fstat(int fd, struct kstat *stat)
{
struct fd f;
int error;
f = fdget_raw(fd);
if (!f.file)
return -EBADF;
error = vfs_getattr(&f.file->f_path, stat, STATX_BASIC_STATS, 0);
fdput(f);
return error;
}
int getname_statx_lookup_flags(int flags)
{
int lookup_flags = 0;
if (!(flags & AT_SYMLINK_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
if (!(flags & AT_NO_AUTOMOUNT))
lookup_flags |= LOOKUP_AUTOMOUNT;
if (flags & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
return lookup_flags;
}
/**
* vfs_statx - Get basic and extra attributes by filename
* @dfd: A file descriptor representing the base dir for a relative filename
* @filename: The name of the file of interest
* @flags: Flags to control the query
* @stat: The result structure to fill in.
* @request_mask: STATX_xxx flags indicating what the caller wants
*
* This function is a wrapper around vfs_getattr(). The main difference is
* that it uses a filename and base directory to determine the file location.
* Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
* at the given name from being referenced.
*
* 0 will be returned on success, and a -ve error code if unsuccessful.
*/
static int vfs_statx(int dfd, struct filename *filename, int flags,
struct kstat *stat, u32 request_mask)
{
struct path path;
unsigned int lookup_flags = getname_statx_lookup_flags(flags);
int error;
if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
AT_STATX_SYNC_TYPE))
return -EINVAL;
retry:
error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
if (error)
goto out;
error = vfs_getattr(&path, stat, request_mask, flags);
stat->mnt_id = real_mount(path.mnt)->mnt_id;
stat->result_mask |= STATX_MNT_ID;
if (path.mnt->mnt_root == path.dentry)
stat->attributes |= STATX_ATTR_MOUNT_ROOT;
stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
/* Handle STATX_DIOALIGN for block devices. */
if (request_mask & STATX_DIOALIGN) {
struct inode *inode = d_backing_inode(path.dentry);
if (S_ISBLK(inode->i_mode))
bdev_statx_dioalign(inode, stat);
}
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out:
return error;
}
int vfs_fstatat(int dfd, const char __user *filename,
struct kstat *stat, int flags)
{
int ret;
int statx_flags = flags | AT_NO_AUTOMOUNT;
struct filename *name;
/*
* Work around glibc turning fstat() into fstatat(AT_EMPTY_PATH)
*
* If AT_EMPTY_PATH is set, we expect the common case to be that
* empty path, and avoid doing all the extra pathname work.
*/
if (dfd >= 0 && flags == AT_EMPTY_PATH) {
char c;
ret = get_user(c, filename);
if (unlikely(ret))
return ret;
if (likely(!c))
return vfs_fstat(dfd, stat);
}
name = getname_flags(filename, getname_statx_lookup_flags(statx_flags), NULL);
ret = vfs_statx(dfd, name, statx_flags, stat, STATX_BASIC_STATS);
putname(name);
return ret;
}
#ifdef __ARCH_WANT_OLD_STAT
/*
* For backward compatibility? Maybe this should be moved
* into arch/i386 instead?
*/
static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
{
static int warncount = 5;
struct __old_kernel_stat tmp;
if (warncount > 0) {
warncount--;
printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
current->comm);
} else if (warncount < 0) {
/* it's laughable, but... */
warncount = 0;
}
memset(&tmp, 0, sizeof(struct __old_kernel_stat));
tmp.st_dev = old_encode_dev(stat->dev);
tmp.st_ino = stat->ino;
if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
return -EOVERFLOW;
tmp.st_mode = stat->mode;
tmp.st_nlink = stat->nlink;
if (tmp.st_nlink != stat->nlink)
return -EOVERFLOW;
SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
tmp.st_rdev = old_encode_dev(stat->rdev);
#if BITS_PER_LONG == 32
if (stat->size > MAX_NON_LFS)
return -EOVERFLOW;
#endif
tmp.st_size = stat->size;
tmp.st_atime = stat->atime.tv_sec;
tmp.st_mtime = stat->mtime.tv_sec;
tmp.st_ctime = stat->ctime.tv_sec;
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}
SYSCALL_DEFINE2(stat, const char __user *, filename,
struct __old_kernel_stat __user *, statbuf)
{
struct kstat stat;
int error;
error = vfs_stat(filename, &stat);
if (error)
return error;
return cp_old_stat(&stat, statbuf);
}
SYSCALL_DEFINE2(lstat, const char __user *, filename,
struct __old_kernel_stat __user *, statbuf)
{
struct kstat stat;
int error;
error = vfs_lstat(filename, &stat);
if (error)
return error;
return cp_old_stat(&stat, statbuf);
}
SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
{
struct kstat stat;
int error = vfs_fstat(fd, &stat);
if (!error)
error = cp_old_stat(&stat, statbuf);
return error;
}
#endif /* __ARCH_WANT_OLD_STAT */
#ifdef __ARCH_WANT_NEW_STAT
#ifndef INIT_STRUCT_STAT_PADDING
# define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
#endif
static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
{
struct stat tmp;
if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
return -EOVERFLOW;
if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
return -EOVERFLOW;
#if BITS_PER_LONG == 32
if (stat->size > MAX_NON_LFS)
return -EOVERFLOW;
#endif
INIT_STRUCT_STAT_PADDING(tmp);
tmp.st_dev = new_encode_dev(stat->dev);
tmp.st_ino = stat->ino;
if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
return -EOVERFLOW;
tmp.st_mode = stat->mode;
tmp.st_nlink = stat->nlink;
if (tmp.st_nlink != stat->nlink)
return -EOVERFLOW;
SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
tmp.st_rdev = new_encode_dev(stat->rdev);
tmp.st_size = stat->size;
tmp.st_atime = stat->atime.tv_sec;
tmp.st_mtime = stat->mtime.tv_sec;
tmp.st_ctime = stat->ctime.tv_sec;
#ifdef STAT_HAVE_NSEC
tmp.st_atime_nsec = stat->atime.tv_nsec;
tmp.st_mtime_nsec = stat->mtime.tv_nsec;
tmp.st_ctime_nsec = stat->ctime.tv_nsec;
#endif
tmp.st_blocks = stat->blocks;
tmp.st_blksize = stat->blksize;
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}
SYSCALL_DEFINE2(newstat, const char __user *, filename,
struct stat __user *, statbuf)
{
struct kstat stat;
int error = vfs_stat(filename, &stat);
if (error)
return error;
return cp_new_stat(&stat, statbuf);
}
SYSCALL_DEFINE2(newlstat, const char __user *, filename,
struct stat __user *, statbuf)
{
struct kstat stat;
int error;
error = vfs_lstat(filename, &stat);
if (error)
return error;
return cp_new_stat(&stat, statbuf);
}
#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
struct stat __user *, statbuf, int, flag)
{
struct kstat stat;
int error;
error = vfs_fstatat(dfd, filename, &stat, flag);
if (error)
return error;
return cp_new_stat(&stat, statbuf);
}
#endif
SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
{
struct kstat stat;
int error = vfs_fstat(fd, &stat);
if (!error)
error = cp_new_stat(&stat, statbuf);
return error;
}
#endif
static int do_readlinkat(int dfd, const char __user *pathname,
char __user *buf, int bufsiz)
{
struct path path;
int error;
int empty = 0;
unsigned int lookup_flags = LOOKUP_EMPTY;
if (bufsiz <= 0)
return -EINVAL;
retry:
error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
if (!error) {
struct inode *inode = d_backing_inode(path.dentry);
error = empty ? -ENOENT : -EINVAL;
/*
* AFS mountpoints allow readlink(2) but are not symlinks
*/
if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
error = security_inode_readlink(path.dentry);
if (!error) {
touch_atime(&path);
error = vfs_readlink(path.dentry, buf, bufsiz);
}
}
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
return error;
}
SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
char __user *, buf, int, bufsiz)
{
return do_readlinkat(dfd, pathname, buf, bufsiz);
}
SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
int, bufsiz)
{
return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
}
/* ---------- LFS-64 ----------- */
#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
#ifndef INIT_STRUCT_STAT64_PADDING
# define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
#endif
static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
{
struct stat64 tmp;
INIT_STRUCT_STAT64_PADDING(tmp);
#ifdef CONFIG_MIPS
/* mips has weird padding, so we don't get 64 bits there */
tmp.st_dev = new_encode_dev(stat->dev);
tmp.st_rdev = new_encode_dev(stat->rdev);
#else
tmp.st_dev = huge_encode_dev(stat->dev);
tmp.st_rdev = huge_encode_dev(stat->rdev);
#endif
tmp.st_ino = stat->ino;
if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
return -EOVERFLOW;
#ifdef STAT64_HAS_BROKEN_ST_INO
tmp.__st_ino = stat->ino;
#endif
tmp.st_mode = stat->mode;
tmp.st_nlink = stat->nlink;
tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
tmp.st_atime = stat->atime.tv_sec;
tmp.st_atime_nsec = stat->atime.tv_nsec;
tmp.st_mtime = stat->mtime.tv_sec;
tmp.st_mtime_nsec = stat->mtime.tv_nsec;
tmp.st_ctime = stat->ctime.tv_sec;
tmp.st_ctime_nsec = stat->ctime.tv_nsec;
tmp.st_size = stat->size;
tmp.st_blocks = stat->blocks;
tmp.st_blksize = stat->blksize;
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}
SYSCALL_DEFINE2(stat64, const char __user *, filename,
struct stat64 __user *, statbuf)
{
struct kstat stat;
int error = vfs_stat(filename, &stat);
if (!error)
error = cp_new_stat64(&stat, statbuf);
return error;
}
SYSCALL_DEFINE2(lstat64, const char __user *, filename,
struct stat64 __user *, statbuf)
{
struct kstat stat;
int error = vfs_lstat(filename, &stat);
if (!error)
error = cp_new_stat64(&stat, statbuf);
return error;
}
SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
{
struct kstat stat;
int error = vfs_fstat(fd, &stat);
if (!error)
error = cp_new_stat64(&stat, statbuf);
return error;
}
SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
struct stat64 __user *, statbuf, int, flag)
{
struct kstat stat;
int error;
error = vfs_fstatat(dfd, filename, &stat, flag);
if (error)
return error;
return cp_new_stat64(&stat, statbuf);
}
#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
static noinline_for_stack int
cp_statx(const struct kstat *stat, struct statx __user *buffer)
{
struct statx tmp;
memset(&tmp, 0, sizeof(tmp));
/* STATX_CHANGE_COOKIE is kernel-only for now */
tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE;
tmp.stx_blksize = stat->blksize;
/* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */
tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC;
tmp.stx_nlink = stat->nlink;
tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
tmp.stx_mode = stat->mode;
tmp.stx_ino = stat->ino;
tmp.stx_size = stat->size;
tmp.stx_blocks = stat->blocks;
tmp.stx_attributes_mask = stat->attributes_mask;
tmp.stx_atime.tv_sec = stat->atime.tv_sec;
tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
tmp.stx_btime.tv_sec = stat->btime.tv_sec;
tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
tmp.stx_rdev_major = MAJOR(stat->rdev);
tmp.stx_rdev_minor = MINOR(stat->rdev);
tmp.stx_dev_major = MAJOR(stat->dev);
tmp.stx_dev_minor = MINOR(stat->dev);
tmp.stx_mnt_id = stat->mnt_id;
tmp.stx_dio_mem_align = stat->dio_mem_align;
tmp.stx_dio_offset_align = stat->dio_offset_align;
return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}
int do_statx(int dfd, struct filename *filename, unsigned int flags,
unsigned int mask, struct statx __user *buffer)
{
struct kstat stat;
int error;
if (mask & STATX__RESERVED)
return -EINVAL;
if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
return -EINVAL;
/* STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
* from userland.
*/
mask &= ~STATX_CHANGE_COOKIE;
error = vfs_statx(dfd, filename, flags, &stat, mask);
if (error)
return error;
return cp_statx(&stat, buffer);
}
/**
* sys_statx - System call to get enhanced stats
* @dfd: Base directory to pathwalk from *or* fd to stat.
* @filename: File to stat or "" with AT_EMPTY_PATH
* @flags: AT_* flags to control pathwalk.
* @mask: Parts of statx struct actually required.
* @buffer: Result buffer.
*
* Note that fstat() can be emulated by setting dfd to the fd of interest,
* supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
*/
SYSCALL_DEFINE5(statx,
int, dfd, const char __user *, filename, unsigned, flags,
unsigned int, mask,
struct statx __user *, buffer)
{
int ret;
struct filename *name;
name = getname_flags(filename, getname_statx_lookup_flags(flags), NULL);
ret = do_statx(dfd, name, flags, mask, buffer);
putname(name);
return ret;
}
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
{
struct compat_stat tmp;
if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
return -EOVERFLOW;
if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
return -EOVERFLOW;
memset(&tmp, 0, sizeof(tmp));
tmp.st_dev = new_encode_dev(stat->dev);
tmp.st_ino = stat->ino;
if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
return -EOVERFLOW;
tmp.st_mode = stat->mode;
tmp.st_nlink = stat->nlink;
if (tmp.st_nlink != stat->nlink)
return -EOVERFLOW;
SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
tmp.st_rdev = new_encode_dev(stat->rdev);
if ((u64) stat->size > MAX_NON_LFS)
return -EOVERFLOW;
tmp.st_size = stat->size;
tmp.st_atime = stat->atime.tv_sec;
tmp.st_atime_nsec = stat->atime.tv_nsec;
tmp.st_mtime = stat->mtime.tv_sec;
tmp.st_mtime_nsec = stat->mtime.tv_nsec;
tmp.st_ctime = stat->ctime.tv_sec;
tmp.st_ctime_nsec = stat->ctime.tv_nsec;
tmp.st_blocks = stat->blocks;
tmp.st_blksize = stat->blksize;
return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}
COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
struct compat_stat __user *, statbuf)
{
struct kstat stat;
int error;
error = vfs_stat(filename, &stat);
if (error)
return error;
return cp_compat_stat(&stat, statbuf);
}
COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
struct compat_stat __user *, statbuf)
{
struct kstat stat;
int error;
error = vfs_lstat(filename, &stat);
if (error)
return error;
return cp_compat_stat(&stat, statbuf);
}
#ifndef __ARCH_WANT_STAT64
COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
const char __user *, filename,
struct compat_stat __user *, statbuf, int, flag)
{
struct kstat stat;
int error;
error = vfs_fstatat(dfd, filename, &stat, flag);
if (error)
return error;
return cp_compat_stat(&stat, statbuf);
}
#endif
COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
struct compat_stat __user *, statbuf)
{
struct kstat stat;
int error = vfs_fstat(fd, &stat);
if (!error)
error = cp_compat_stat(&stat, statbuf);
return error;
}
#endif
/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
void __inode_add_bytes(struct inode *inode, loff_t bytes)
{
inode->i_blocks += bytes >> 9;
bytes &= 511;
inode->i_bytes += bytes;
if (inode->i_bytes >= 512) {
inode->i_blocks++;
inode->i_bytes -= 512;
}
}
EXPORT_SYMBOL(__inode_add_bytes);
void inode_add_bytes(struct inode *inode, loff_t bytes)
{
spin_lock(&inode->i_lock);
__inode_add_bytes(inode, bytes);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(inode_add_bytes);
void __inode_sub_bytes(struct inode *inode, loff_t bytes)
{
inode->i_blocks -= bytes >> 9;
bytes &= 511;
if (inode->i_bytes < bytes) {
inode->i_blocks--;
inode->i_bytes += 512;
}
inode->i_bytes -= bytes;
}
EXPORT_SYMBOL(__inode_sub_bytes);
void inode_sub_bytes(struct inode *inode, loff_t bytes)
{
spin_lock(&inode->i_lock);
__inode_sub_bytes(inode, bytes);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(inode_sub_bytes);
loff_t inode_get_bytes(struct inode *inode)
{
loff_t ret;
spin_lock(&inode->i_lock);
ret = __inode_get_bytes(inode);
spin_unlock(&inode->i_lock);
return ret;
}
EXPORT_SYMBOL(inode_get_bytes);
void inode_set_bytes(struct inode *inode, loff_t bytes)
{
/* Caller is here responsible for sufficient locking
* (ie. inode->i_lock) */
inode->i_blocks = bytes >> 9;
inode->i_bytes = bytes & 511;
}
EXPORT_SYMBOL(inode_set_bytes);
| linux-master | fs/stat.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/statfs.h>
#include <linux/security.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
#include "internal.h"
static int flags_by_mnt(int mnt_flags)
{
int flags = 0;
if (mnt_flags & MNT_READONLY)
flags |= ST_RDONLY;
if (mnt_flags & MNT_NOSUID)
flags |= ST_NOSUID;
if (mnt_flags & MNT_NODEV)
flags |= ST_NODEV;
if (mnt_flags & MNT_NOEXEC)
flags |= ST_NOEXEC;
if (mnt_flags & MNT_NOATIME)
flags |= ST_NOATIME;
if (mnt_flags & MNT_NODIRATIME)
flags |= ST_NODIRATIME;
if (mnt_flags & MNT_RELATIME)
flags |= ST_RELATIME;
if (mnt_flags & MNT_NOSYMFOLLOW)
flags |= ST_NOSYMFOLLOW;
return flags;
}
static int flags_by_sb(int s_flags)
{
int flags = 0;
if (s_flags & SB_SYNCHRONOUS)
flags |= ST_SYNCHRONOUS;
if (s_flags & SB_MANDLOCK)
flags |= ST_MANDLOCK;
if (s_flags & SB_RDONLY)
flags |= ST_RDONLY;
return flags;
}
static int calculate_f_flags(struct vfsmount *mnt)
{
return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
flags_by_sb(mnt->mnt_sb->s_flags);
}
static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
{
int retval;
if (!dentry->d_sb->s_op->statfs)
return -ENOSYS;
memset(buf, 0, sizeof(*buf));
retval = security_sb_statfs(dentry);
if (retval)
return retval;
retval = dentry->d_sb->s_op->statfs(dentry, buf);
if (retval == 0 && buf->f_frsize == 0)
buf->f_frsize = buf->f_bsize;
return retval;
}
int vfs_get_fsid(struct dentry *dentry, __kernel_fsid_t *fsid)
{
struct kstatfs st;
int error;
error = statfs_by_dentry(dentry, &st);
if (error)
return error;
*fsid = st.f_fsid;
return 0;
}
EXPORT_SYMBOL(vfs_get_fsid);
int vfs_statfs(const struct path *path, struct kstatfs *buf)
{
int error;
error = statfs_by_dentry(path->dentry, buf);
if (!error)
buf->f_flags = calculate_f_flags(path->mnt);
return error;
}
EXPORT_SYMBOL(vfs_statfs);
int user_statfs(const char __user *pathname, struct kstatfs *st)
{
struct path path;
int error;
unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT;
retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
if (!error) {
error = vfs_statfs(&path, st);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
return error;
}
int fd_statfs(int fd, struct kstatfs *st)
{
struct fd f = fdget_raw(fd);
int error = -EBADF;
if (f.file) {
error = vfs_statfs(&f.file->f_path, st);
fdput(f);
}
return error;
}
static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
{
struct statfs buf;
if (sizeof(buf) == sizeof(*st))
memcpy(&buf, st, sizeof(*st));
else {
memset(&buf, 0, sizeof(buf));
if (sizeof buf.f_blocks == 4) {
if ((st->f_blocks | st->f_bfree | st->f_bavail |
st->f_bsize | st->f_frsize) &
0xffffffff00000000ULL)
return -EOVERFLOW;
/*
* f_files and f_ffree may be -1; it's okay to stuff
* that into 32 bits
*/
if (st->f_files != -1 &&
(st->f_files & 0xffffffff00000000ULL))
return -EOVERFLOW;
if (st->f_ffree != -1 &&
(st->f_ffree & 0xffffffff00000000ULL))
return -EOVERFLOW;
}
buf.f_type = st->f_type;
buf.f_bsize = st->f_bsize;
buf.f_blocks = st->f_blocks;
buf.f_bfree = st->f_bfree;
buf.f_bavail = st->f_bavail;
buf.f_files = st->f_files;
buf.f_ffree = st->f_ffree;
buf.f_fsid = st->f_fsid;
buf.f_namelen = st->f_namelen;
buf.f_frsize = st->f_frsize;
buf.f_flags = st->f_flags;
}
if (copy_to_user(p, &buf, sizeof(buf)))
return -EFAULT;
return 0;
}
static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
{
struct statfs64 buf;
if (sizeof(buf) == sizeof(*st))
memcpy(&buf, st, sizeof(*st));
else {
memset(&buf, 0, sizeof(buf));
buf.f_type = st->f_type;
buf.f_bsize = st->f_bsize;
buf.f_blocks = st->f_blocks;
buf.f_bfree = st->f_bfree;
buf.f_bavail = st->f_bavail;
buf.f_files = st->f_files;
buf.f_ffree = st->f_ffree;
buf.f_fsid = st->f_fsid;
buf.f_namelen = st->f_namelen;
buf.f_frsize = st->f_frsize;
buf.f_flags = st->f_flags;
}
if (copy_to_user(p, &buf, sizeof(buf)))
return -EFAULT;
return 0;
}
SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
{
struct kstatfs st;
int error = user_statfs(pathname, &st);
if (!error)
error = do_statfs_native(&st, buf);
return error;
}
SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
{
struct kstatfs st;
int error;
if (sz != sizeof(*buf))
return -EINVAL;
error = user_statfs(pathname, &st);
if (!error)
error = do_statfs64(&st, buf);
return error;
}
SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
{
struct kstatfs st;
int error = fd_statfs(fd, &st);
if (!error)
error = do_statfs_native(&st, buf);
return error;
}
SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
{
struct kstatfs st;
int error;
if (sz != sizeof(*buf))
return -EINVAL;
error = fd_statfs(fd, &st);
if (!error)
error = do_statfs64(&st, buf);
return error;
}
static int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
{
struct super_block *s = user_get_super(dev, false);
int err;
if (!s)
return -EINVAL;
err = statfs_by_dentry(s->s_root, sbuf);
drop_super(s);
return err;
}
SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
{
struct ustat tmp;
struct kstatfs sbuf;
int err = vfs_ustat(new_decode_dev(dev), &sbuf);
if (err)
return err;
memset(&tmp,0,sizeof(struct ustat));
tmp.f_tfree = sbuf.f_bfree;
if (IS_ENABLED(CONFIG_ARCH_32BIT_USTAT_F_TINODE))
tmp.f_tinode = min_t(u64, sbuf.f_ffree, UINT_MAX);
else
tmp.f_tinode = sbuf.f_ffree;
return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
}
#ifdef CONFIG_COMPAT
static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf)
{
struct compat_statfs buf;
if (sizeof ubuf->f_blocks == 4) {
if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
return -EOVERFLOW;
/* f_files and f_ffree may be -1; it's okay
* to stuff that into 32 bits */
if (kbuf->f_files != 0xffffffffffffffffULL
&& (kbuf->f_files & 0xffffffff00000000ULL))
return -EOVERFLOW;
if (kbuf->f_ffree != 0xffffffffffffffffULL
&& (kbuf->f_ffree & 0xffffffff00000000ULL))
return -EOVERFLOW;
}
memset(&buf, 0, sizeof(struct compat_statfs));
buf.f_type = kbuf->f_type;
buf.f_bsize = kbuf->f_bsize;
buf.f_blocks = kbuf->f_blocks;
buf.f_bfree = kbuf->f_bfree;
buf.f_bavail = kbuf->f_bavail;
buf.f_files = kbuf->f_files;
buf.f_ffree = kbuf->f_ffree;
buf.f_namelen = kbuf->f_namelen;
buf.f_fsid.val[0] = kbuf->f_fsid.val[0];
buf.f_fsid.val[1] = kbuf->f_fsid.val[1];
buf.f_frsize = kbuf->f_frsize;
buf.f_flags = kbuf->f_flags;
if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs)))
return -EFAULT;
return 0;
}
/*
* The following statfs calls are copies of code from fs/statfs.c and
* should be checked against those from time to time
*/
COMPAT_SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct compat_statfs __user *, buf)
{
struct kstatfs tmp;
int error = user_statfs(pathname, &tmp);
if (!error)
error = put_compat_statfs(buf, &tmp);
return error;
}
COMPAT_SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct compat_statfs __user *, buf)
{
struct kstatfs tmp;
int error = fd_statfs(fd, &tmp);
if (!error)
error = put_compat_statfs(buf, &tmp);
return error;
}
static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf)
{
struct compat_statfs64 buf;
if ((kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
return -EOVERFLOW;
memset(&buf, 0, sizeof(struct compat_statfs64));
buf.f_type = kbuf->f_type;
buf.f_bsize = kbuf->f_bsize;
buf.f_blocks = kbuf->f_blocks;
buf.f_bfree = kbuf->f_bfree;
buf.f_bavail = kbuf->f_bavail;
buf.f_files = kbuf->f_files;
buf.f_ffree = kbuf->f_ffree;
buf.f_namelen = kbuf->f_namelen;
buf.f_fsid.val[0] = kbuf->f_fsid.val[0];
buf.f_fsid.val[1] = kbuf->f_fsid.val[1];
buf.f_frsize = kbuf->f_frsize;
buf.f_flags = kbuf->f_flags;
if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs64)))
return -EFAULT;
return 0;
}
int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, struct compat_statfs64 __user * buf)
{
struct kstatfs tmp;
int error;
if (sz != sizeof(*buf))
return -EINVAL;
error = user_statfs(pathname, &tmp);
if (!error)
error = put_compat_statfs64(buf, &tmp);
return error;
}
COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf)
{
return kcompat_sys_statfs64(pathname, sz, buf);
}
int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user * buf)
{
struct kstatfs tmp;
int error;
if (sz != sizeof(*buf))
return -EINVAL;
error = fd_statfs(fd, &tmp);
if (!error)
error = put_compat_statfs64(buf, &tmp);
return error;
}
COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf)
{
return kcompat_sys_fstatfs64(fd, sz, buf);
}
/*
* This is a copy of sys_ustat, just dealing with a structure layout.
* Given how simple this syscall is that apporach is more maintainable
* than the various conversion hacks.
*/
COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u)
{
struct compat_ustat tmp;
struct kstatfs sbuf;
int err = vfs_ustat(new_decode_dev(dev), &sbuf);
if (err)
return err;
memset(&tmp, 0, sizeof(struct compat_ustat));
tmp.f_tfree = sbuf.f_bfree;
tmp.f_tinode = sbuf.f_ffree;
if (copy_to_user(u, &tmp, sizeof(struct compat_ustat)))
return -EFAULT;
return 0;
}
#endif
| linux-master | fs/statfs.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/anon_inodes.c
*
* Copyright (C) 2007 Davide Libenzi <[email protected]>
*
* Thanks to Arnd Bergmann for code review and suggestions.
* More changes for Thomas Gleixner suggestions.
*
*/
#include <linux/cred.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/magic.h>
#include <linux/anon_inodes.h>
#include <linux/pseudo_fs.h>
#include <linux/uaccess.h>
static struct vfsmount *anon_inode_mnt __read_mostly;
static struct inode *anon_inode_inode;
/*
* anon_inodefs_dname() is called from d_path().
*/
static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen)
{
return dynamic_dname(buffer, buflen, "anon_inode:%s",
dentry->d_name.name);
}
static const struct dentry_operations anon_inodefs_dentry_operations = {
.d_dname = anon_inodefs_dname,
};
static int anon_inodefs_init_fs_context(struct fs_context *fc)
{
struct pseudo_fs_context *ctx = init_pseudo(fc, ANON_INODE_FS_MAGIC);
if (!ctx)
return -ENOMEM;
ctx->dops = &anon_inodefs_dentry_operations;
return 0;
}
static struct file_system_type anon_inode_fs_type = {
.name = "anon_inodefs",
.init_fs_context = anon_inodefs_init_fs_context,
.kill_sb = kill_anon_super,
};
static struct inode *anon_inode_make_secure_inode(
const char *name,
const struct inode *context_inode)
{
struct inode *inode;
const struct qstr qname = QSTR_INIT(name, strlen(name));
int error;
inode = alloc_anon_inode(anon_inode_mnt->mnt_sb);
if (IS_ERR(inode))
return inode;
inode->i_flags &= ~S_PRIVATE;
error = security_inode_init_security_anon(inode, &qname, context_inode);
if (error) {
iput(inode);
return ERR_PTR(error);
}
return inode;
}
static struct file *__anon_inode_getfile(const char *name,
const struct file_operations *fops,
void *priv, int flags,
const struct inode *context_inode,
bool secure)
{
struct inode *inode;
struct file *file;
if (fops->owner && !try_module_get(fops->owner))
return ERR_PTR(-ENOENT);
if (secure) {
inode = anon_inode_make_secure_inode(name, context_inode);
if (IS_ERR(inode)) {
file = ERR_CAST(inode);
goto err;
}
} else {
inode = anon_inode_inode;
if (IS_ERR(inode)) {
file = ERR_PTR(-ENODEV);
goto err;
}
/*
* We know the anon_inode inode count is always
* greater than zero, so ihold() is safe.
*/
ihold(inode);
}
file = alloc_file_pseudo(inode, anon_inode_mnt, name,
flags & (O_ACCMODE | O_NONBLOCK), fops);
if (IS_ERR(file))
goto err_iput;
file->f_mapping = inode->i_mapping;
file->private_data = priv;
return file;
err_iput:
iput(inode);
err:
module_put(fops->owner);
return file;
}
/**
* anon_inode_getfile - creates a new file instance by hooking it up to an
* anonymous inode, and a dentry that describe the "class"
* of the file
*
* @name: [in] name of the "class" of the new file
* @fops: [in] file operations for the new file
* @priv: [in] private data for the new file (will be file's private_data)
* @flags: [in] flags
*
* Creates a new file by hooking it on a single inode. This is useful for files
* that do not need to have a full-fledged inode in order to operate correctly.
* All the files created with anon_inode_getfile() will share a single inode,
* hence saving memory and avoiding code duplication for the file/inode/dentry
* setup. Returns the newly created file* or an error pointer.
*/
struct file *anon_inode_getfile(const char *name,
const struct file_operations *fops,
void *priv, int flags)
{
return __anon_inode_getfile(name, fops, priv, flags, NULL, false);
}
EXPORT_SYMBOL_GPL(anon_inode_getfile);
/**
* anon_inode_getfile_secure - Like anon_inode_getfile(), but creates a new
* !S_PRIVATE anon inode rather than reuse the
* singleton anon inode and calls the
* inode_init_security_anon() LSM hook. This
* allows for both the inode to have its own
* security context and for the LSM to enforce
* policy on the inode's creation.
*
* @name: [in] name of the "class" of the new file
* @fops: [in] file operations for the new file
* @priv: [in] private data for the new file (will be file's private_data)
* @flags: [in] flags
* @context_inode:
* [in] the logical relationship with the new inode (optional)
*
* The LSM may use @context_inode in inode_init_security_anon(), but a
* reference to it is not held. Returns the newly created file* or an error
* pointer. See the anon_inode_getfile() documentation for more information.
*/
struct file *anon_inode_getfile_secure(const char *name,
const struct file_operations *fops,
void *priv, int flags,
const struct inode *context_inode)
{
return __anon_inode_getfile(name, fops, priv, flags,
context_inode, true);
}
static int __anon_inode_getfd(const char *name,
const struct file_operations *fops,
void *priv, int flags,
const struct inode *context_inode,
bool secure)
{
int error, fd;
struct file *file;
error = get_unused_fd_flags(flags);
if (error < 0)
return error;
fd = error;
file = __anon_inode_getfile(name, fops, priv, flags, context_inode,
secure);
if (IS_ERR(file)) {
error = PTR_ERR(file);
goto err_put_unused_fd;
}
fd_install(fd, file);
return fd;
err_put_unused_fd:
put_unused_fd(fd);
return error;
}
/**
* anon_inode_getfd - creates a new file instance by hooking it up to
* an anonymous inode and a dentry that describe
* the "class" of the file
*
* @name: [in] name of the "class" of the new file
* @fops: [in] file operations for the new file
* @priv: [in] private data for the new file (will be file's private_data)
* @flags: [in] flags
*
* Creates a new file by hooking it on a single inode. This is
* useful for files that do not need to have a full-fledged inode in
* order to operate correctly. All the files created with
* anon_inode_getfd() will use the same singleton inode, reducing
* memory use and avoiding code duplication for the file/inode/dentry
* setup. Returns a newly created file descriptor or an error code.
*/
int anon_inode_getfd(const char *name, const struct file_operations *fops,
void *priv, int flags)
{
return __anon_inode_getfd(name, fops, priv, flags, NULL, false);
}
EXPORT_SYMBOL_GPL(anon_inode_getfd);
/**
* anon_inode_getfd_secure - Like anon_inode_getfd(), but creates a new
* !S_PRIVATE anon inode rather than reuse the singleton anon inode, and calls
* the inode_init_security_anon() LSM hook. This allows the inode to have its
* own security context and for a LSM to reject creation of the inode.
*
* @name: [in] name of the "class" of the new file
* @fops: [in] file operations for the new file
* @priv: [in] private data for the new file (will be file's private_data)
* @flags: [in] flags
* @context_inode:
* [in] the logical relationship with the new inode (optional)
*
* The LSM may use @context_inode in inode_init_security_anon(), but a
* reference to it is not held.
*/
int anon_inode_getfd_secure(const char *name, const struct file_operations *fops,
void *priv, int flags,
const struct inode *context_inode)
{
return __anon_inode_getfd(name, fops, priv, flags, context_inode, true);
}
EXPORT_SYMBOL_GPL(anon_inode_getfd_secure);
static int __init anon_inode_init(void)
{
anon_inode_mnt = kern_mount(&anon_inode_fs_type);
if (IS_ERR(anon_inode_mnt))
panic("anon_inode_init() kernel mount failed (%ld)\n", PTR_ERR(anon_inode_mnt));
anon_inode_inode = alloc_anon_inode(anon_inode_mnt->mnt_sb);
if (IS_ERR(anon_inode_inode))
panic("anon_inode_init() inode allocation failed (%ld)\n", PTR_ERR(anon_inode_inode));
return 0;
}
fs_initcall(anon_inode_init);
| linux-master | fs/anon_inodes.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/fcntl.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/syscalls.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/sched/task.h>
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/capability.h>
#include <linux/dnotify.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/pipe_fs_i.h>
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/signal.h>
#include <linux/rcupdate.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include <linux/memfd.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/poll.h>
#include <asm/siginfo.h>
#include <linux/uaccess.h>
#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
static int setfl(int fd, struct file * filp, unsigned int arg)
{
struct inode * inode = file_inode(filp);
int error = 0;
/*
* O_APPEND cannot be cleared if the file is marked as append-only
* and the file is open for write.
*/
if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
return -EPERM;
/* O_NOATIME can only be set by the owner or superuser */
if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
if (!inode_owner_or_capable(file_mnt_idmap(filp), inode))
return -EPERM;
/* required for strict SunOS emulation */
if (O_NONBLOCK != O_NDELAY)
if (arg & O_NDELAY)
arg |= O_NONBLOCK;
/* Pipe packetized mode is controlled by O_DIRECT flag */
if (!S_ISFIFO(inode->i_mode) &&
(arg & O_DIRECT) &&
!(filp->f_mode & FMODE_CAN_ODIRECT))
return -EINVAL;
if (filp->f_op->check_flags)
error = filp->f_op->check_flags(arg);
if (error)
return error;
/*
* ->fasync() is responsible for setting the FASYNC bit.
*/
if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
if (error < 0)
goto out;
if (error > 0)
error = 0;
}
spin_lock(&filp->f_lock);
filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
filp->f_iocb_flags = iocb_flags(filp);
spin_unlock(&filp->f_lock);
out:
return error;
}
static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
int force)
{
write_lock_irq(&filp->f_owner.lock);
if (force || !filp->f_owner.pid) {
put_pid(filp->f_owner.pid);
filp->f_owner.pid = get_pid(pid);
filp->f_owner.pid_type = type;
if (pid) {
const struct cred *cred = current_cred();
filp->f_owner.uid = cred->uid;
filp->f_owner.euid = cred->euid;
}
}
write_unlock_irq(&filp->f_owner.lock);
}
void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
int force)
{
security_file_set_fowner(filp);
f_modown(filp, pid, type, force);
}
EXPORT_SYMBOL(__f_setown);
int f_setown(struct file *filp, int who, int force)
{
enum pid_type type;
struct pid *pid = NULL;
int ret = 0;
type = PIDTYPE_TGID;
if (who < 0) {
/* avoid overflow below */
if (who == INT_MIN)
return -EINVAL;
type = PIDTYPE_PGID;
who = -who;
}
rcu_read_lock();
if (who) {
pid = find_vpid(who);
if (!pid)
ret = -ESRCH;
}
if (!ret)
__f_setown(filp, pid, type, force);
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL(f_setown);
void f_delown(struct file *filp)
{
f_modown(filp, NULL, PIDTYPE_TGID, 1);
}
pid_t f_getown(struct file *filp)
{
pid_t pid = 0;
read_lock_irq(&filp->f_owner.lock);
rcu_read_lock();
if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type)) {
pid = pid_vnr(filp->f_owner.pid);
if (filp->f_owner.pid_type == PIDTYPE_PGID)
pid = -pid;
}
rcu_read_unlock();
read_unlock_irq(&filp->f_owner.lock);
return pid;
}
static int f_setown_ex(struct file *filp, unsigned long arg)
{
struct f_owner_ex __user *owner_p = (void __user *)arg;
struct f_owner_ex owner;
struct pid *pid;
int type;
int ret;
ret = copy_from_user(&owner, owner_p, sizeof(owner));
if (ret)
return -EFAULT;
switch (owner.type) {
case F_OWNER_TID:
type = PIDTYPE_PID;
break;
case F_OWNER_PID:
type = PIDTYPE_TGID;
break;
case F_OWNER_PGRP:
type = PIDTYPE_PGID;
break;
default:
return -EINVAL;
}
rcu_read_lock();
pid = find_vpid(owner.pid);
if (owner.pid && !pid)
ret = -ESRCH;
else
__f_setown(filp, pid, type, 1);
rcu_read_unlock();
return ret;
}
static int f_getown_ex(struct file *filp, unsigned long arg)
{
struct f_owner_ex __user *owner_p = (void __user *)arg;
struct f_owner_ex owner = {};
int ret = 0;
read_lock_irq(&filp->f_owner.lock);
rcu_read_lock();
if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type))
owner.pid = pid_vnr(filp->f_owner.pid);
rcu_read_unlock();
switch (filp->f_owner.pid_type) {
case PIDTYPE_PID:
owner.type = F_OWNER_TID;
break;
case PIDTYPE_TGID:
owner.type = F_OWNER_PID;
break;
case PIDTYPE_PGID:
owner.type = F_OWNER_PGRP;
break;
default:
WARN_ON(1);
ret = -EINVAL;
break;
}
read_unlock_irq(&filp->f_owner.lock);
if (!ret) {
ret = copy_to_user(owner_p, &owner, sizeof(owner));
if (ret)
ret = -EFAULT;
}
return ret;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static int f_getowner_uids(struct file *filp, unsigned long arg)
{
struct user_namespace *user_ns = current_user_ns();
uid_t __user *dst = (void __user *)arg;
uid_t src[2];
int err;
read_lock_irq(&filp->f_owner.lock);
src[0] = from_kuid(user_ns, filp->f_owner.uid);
src[1] = from_kuid(user_ns, filp->f_owner.euid);
read_unlock_irq(&filp->f_owner.lock);
err = put_user(src[0], &dst[0]);
err |= put_user(src[1], &dst[1]);
return err;
}
#else
static int f_getowner_uids(struct file *filp, unsigned long arg)
{
return -EINVAL;
}
#endif
static bool rw_hint_valid(enum rw_hint hint)
{
switch (hint) {
case RWH_WRITE_LIFE_NOT_SET:
case RWH_WRITE_LIFE_NONE:
case RWH_WRITE_LIFE_SHORT:
case RWH_WRITE_LIFE_MEDIUM:
case RWH_WRITE_LIFE_LONG:
case RWH_WRITE_LIFE_EXTREME:
return true;
default:
return false;
}
}
static long fcntl_rw_hint(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct inode *inode = file_inode(file);
u64 __user *argp = (u64 __user *)arg;
enum rw_hint hint;
u64 h;
switch (cmd) {
case F_GET_RW_HINT:
h = inode->i_write_hint;
if (copy_to_user(argp, &h, sizeof(*argp)))
return -EFAULT;
return 0;
case F_SET_RW_HINT:
if (copy_from_user(&h, argp, sizeof(h)))
return -EFAULT;
hint = (enum rw_hint) h;
if (!rw_hint_valid(hint))
return -EINVAL;
inode_lock(inode);
inode->i_write_hint = hint;
inode_unlock(inode);
return 0;
default:
return -EINVAL;
}
}
static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
struct file *filp)
{
void __user *argp = (void __user *)arg;
int argi = (int)arg;
struct flock flock;
long err = -EINVAL;
switch (cmd) {
case F_DUPFD:
err = f_dupfd(argi, filp, 0);
break;
case F_DUPFD_CLOEXEC:
err = f_dupfd(argi, filp, O_CLOEXEC);
break;
case F_GETFD:
err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
break;
case F_SETFD:
err = 0;
set_close_on_exec(fd, argi & FD_CLOEXEC);
break;
case F_GETFL:
err = filp->f_flags;
break;
case F_SETFL:
err = setfl(fd, filp, argi);
break;
#if BITS_PER_LONG != 32
/* 32-bit arches must use fcntl64() */
case F_OFD_GETLK:
#endif
case F_GETLK:
if (copy_from_user(&flock, argp, sizeof(flock)))
return -EFAULT;
err = fcntl_getlk(filp, cmd, &flock);
if (!err && copy_to_user(argp, &flock, sizeof(flock)))
return -EFAULT;
break;
#if BITS_PER_LONG != 32
/* 32-bit arches must use fcntl64() */
case F_OFD_SETLK:
case F_OFD_SETLKW:
fallthrough;
#endif
case F_SETLK:
case F_SETLKW:
if (copy_from_user(&flock, argp, sizeof(flock)))
return -EFAULT;
err = fcntl_setlk(fd, filp, cmd, &flock);
break;
case F_GETOWN:
/*
* XXX If f_owner is a process group, the
* negative return value will get converted
* into an error. Oops. If we keep the
* current syscall conventions, the only way
* to fix this will be in libc.
*/
err = f_getown(filp);
force_successful_syscall_return();
break;
case F_SETOWN:
err = f_setown(filp, argi, 1);
break;
case F_GETOWN_EX:
err = f_getown_ex(filp, arg);
break;
case F_SETOWN_EX:
err = f_setown_ex(filp, arg);
break;
case F_GETOWNER_UIDS:
err = f_getowner_uids(filp, arg);
break;
case F_GETSIG:
err = filp->f_owner.signum;
break;
case F_SETSIG:
/* arg == 0 restores default behaviour. */
if (!valid_signal(argi)) {
break;
}
err = 0;
filp->f_owner.signum = argi;
break;
case F_GETLEASE:
err = fcntl_getlease(filp);
break;
case F_SETLEASE:
err = fcntl_setlease(fd, filp, argi);
break;
case F_NOTIFY:
err = fcntl_dirnotify(fd, filp, argi);
break;
case F_SETPIPE_SZ:
case F_GETPIPE_SZ:
err = pipe_fcntl(filp, cmd, argi);
break;
case F_ADD_SEALS:
case F_GET_SEALS:
err = memfd_fcntl(filp, cmd, argi);
break;
case F_GET_RW_HINT:
case F_SET_RW_HINT:
err = fcntl_rw_hint(filp, cmd, arg);
break;
default:
break;
}
return err;
}
static int check_fcntl_cmd(unsigned cmd)
{
switch (cmd) {
case F_DUPFD:
case F_DUPFD_CLOEXEC:
case F_GETFD:
case F_SETFD:
case F_GETFL:
return 1;
}
return 0;
}
SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
{
struct fd f = fdget_raw(fd);
long err = -EBADF;
if (!f.file)
goto out;
if (unlikely(f.file->f_mode & FMODE_PATH)) {
if (!check_fcntl_cmd(cmd))
goto out1;
}
err = security_file_fcntl(f.file, cmd, arg);
if (!err)
err = do_fcntl(fd, cmd, arg, f.file);
out1:
fdput(f);
out:
return err;
}
#if BITS_PER_LONG == 32
SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
unsigned long, arg)
{
void __user *argp = (void __user *)arg;
struct fd f = fdget_raw(fd);
struct flock64 flock;
long err = -EBADF;
if (!f.file)
goto out;
if (unlikely(f.file->f_mode & FMODE_PATH)) {
if (!check_fcntl_cmd(cmd))
goto out1;
}
err = security_file_fcntl(f.file, cmd, arg);
if (err)
goto out1;
switch (cmd) {
case F_GETLK64:
case F_OFD_GETLK:
err = -EFAULT;
if (copy_from_user(&flock, argp, sizeof(flock)))
break;
err = fcntl_getlk64(f.file, cmd, &flock);
if (!err && copy_to_user(argp, &flock, sizeof(flock)))
err = -EFAULT;
break;
case F_SETLK64:
case F_SETLKW64:
case F_OFD_SETLK:
case F_OFD_SETLKW:
err = -EFAULT;
if (copy_from_user(&flock, argp, sizeof(flock)))
break;
err = fcntl_setlk64(fd, f.file, cmd, &flock);
break;
default:
err = do_fcntl(fd, cmd, arg, f.file);
break;
}
out1:
fdput(f);
out:
return err;
}
#endif
#ifdef CONFIG_COMPAT
/* careful - don't use anywhere else */
#define copy_flock_fields(dst, src) \
(dst)->l_type = (src)->l_type; \
(dst)->l_whence = (src)->l_whence; \
(dst)->l_start = (src)->l_start; \
(dst)->l_len = (src)->l_len; \
(dst)->l_pid = (src)->l_pid;
static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl)
{
struct compat_flock fl;
if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
return -EFAULT;
copy_flock_fields(kfl, &fl);
return 0;
}
static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl)
{
struct compat_flock64 fl;
if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
return -EFAULT;
copy_flock_fields(kfl, &fl);
return 0;
}
static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl)
{
struct compat_flock fl;
memset(&fl, 0, sizeof(struct compat_flock));
copy_flock_fields(&fl, kfl);
if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
return -EFAULT;
return 0;
}
static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl)
{
struct compat_flock64 fl;
BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start));
BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len));
memset(&fl, 0, sizeof(struct compat_flock64));
copy_flock_fields(&fl, kfl);
if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
return -EFAULT;
return 0;
}
#undef copy_flock_fields
static unsigned int
convert_fcntl_cmd(unsigned int cmd)
{
switch (cmd) {
case F_GETLK64:
return F_GETLK;
case F_SETLK64:
return F_SETLK;
case F_SETLKW64:
return F_SETLKW;
}
return cmd;
}
/*
* GETLK was successful and we need to return the data, but it needs to fit in
* the compat structure.
* l_start shouldn't be too big, unless the original start + end is greater than
* COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
* -EOVERFLOW in that case. l_len could be too big, in which case we just
* truncate it, and only allow the app to see that part of the conflicting lock
* that might make sense to it anyway
*/
static int fixup_compat_flock(struct flock *flock)
{
if (flock->l_start > COMPAT_OFF_T_MAX)
return -EOVERFLOW;
if (flock->l_len > COMPAT_OFF_T_MAX)
flock->l_len = COMPAT_OFF_T_MAX;
return 0;
}
static long do_compat_fcntl64(unsigned int fd, unsigned int cmd,
compat_ulong_t arg)
{
struct fd f = fdget_raw(fd);
struct flock flock;
long err = -EBADF;
if (!f.file)
return err;
if (unlikely(f.file->f_mode & FMODE_PATH)) {
if (!check_fcntl_cmd(cmd))
goto out_put;
}
err = security_file_fcntl(f.file, cmd, arg);
if (err)
goto out_put;
switch (cmd) {
case F_GETLK:
err = get_compat_flock(&flock, compat_ptr(arg));
if (err)
break;
err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
if (err)
break;
err = fixup_compat_flock(&flock);
if (!err)
err = put_compat_flock(&flock, compat_ptr(arg));
break;
case F_GETLK64:
case F_OFD_GETLK:
err = get_compat_flock64(&flock, compat_ptr(arg));
if (err)
break;
err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
if (!err)
err = put_compat_flock64(&flock, compat_ptr(arg));
break;
case F_SETLK:
case F_SETLKW:
err = get_compat_flock(&flock, compat_ptr(arg));
if (err)
break;
err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
break;
case F_SETLK64:
case F_SETLKW64:
case F_OFD_SETLK:
case F_OFD_SETLKW:
err = get_compat_flock64(&flock, compat_ptr(arg));
if (err)
break;
err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
break;
default:
err = do_fcntl(fd, cmd, arg, f.file);
break;
}
out_put:
fdput(f);
return err;
}
COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
compat_ulong_t, arg)
{
return do_compat_fcntl64(fd, cmd, arg);
}
COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
compat_ulong_t, arg)
{
switch (cmd) {
case F_GETLK64:
case F_SETLK64:
case F_SETLKW64:
case F_OFD_GETLK:
case F_OFD_SETLK:
case F_OFD_SETLKW:
return -EINVAL;
}
return do_compat_fcntl64(fd, cmd, arg);
}
#endif
/* Table to convert sigio signal codes into poll band bitmaps */
static const __poll_t band_table[NSIGPOLL] = {
EPOLLIN | EPOLLRDNORM, /* POLL_IN */
EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */
EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */
EPOLLERR, /* POLL_ERR */
EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */
EPOLLHUP | EPOLLERR /* POLL_HUP */
};
static inline int sigio_perm(struct task_struct *p,
struct fown_struct *fown, int sig)
{
const struct cred *cred;
int ret;
rcu_read_lock();
cred = __task_cred(p);
ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
!security_file_send_sigiotask(p, fown, sig));
rcu_read_unlock();
return ret;
}
static void send_sigio_to_task(struct task_struct *p,
struct fown_struct *fown,
int fd, int reason, enum pid_type type)
{
/*
* F_SETSIG can change ->signum lockless in parallel, make
* sure we read it once and use the same value throughout.
*/
int signum = READ_ONCE(fown->signum);
if (!sigio_perm(p, fown, signum))
return;
switch (signum) {
default: {
kernel_siginfo_t si;
/* Queue a rt signal with the appropriate fd as its
value. We use SI_SIGIO as the source, not
SI_KERNEL, since kernel signals always get
delivered even if we can't queue. Failure to
queue in this case _should_ be reported; we fall
back to SIGIO in that case. --sct */
clear_siginfo(&si);
si.si_signo = signum;
si.si_errno = 0;
si.si_code = reason;
/*
* Posix definies POLL_IN and friends to be signal
* specific si_codes for SIG_POLL. Linux extended
* these si_codes to other signals in a way that is
* ambiguous if other signals also have signal
* specific si_codes. In that case use SI_SIGIO instead
* to remove the ambiguity.
*/
if ((signum != SIGPOLL) && sig_specific_sicodes(signum))
si.si_code = SI_SIGIO;
/* Make sure we are called with one of the POLL_*
reasons, otherwise we could leak kernel stack into
userspace. */
BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL));
if (reason - POLL_IN >= NSIGPOLL)
si.si_band = ~0L;
else
si.si_band = mangle_poll(band_table[reason - POLL_IN]);
si.si_fd = fd;
if (!do_send_sig_info(signum, &si, p, type))
break;
}
fallthrough; /* fall back on the old plain SIGIO signal */
case 0:
do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);
}
}
void send_sigio(struct fown_struct *fown, int fd, int band)
{
struct task_struct *p;
enum pid_type type;
unsigned long flags;
struct pid *pid;
read_lock_irqsave(&fown->lock, flags);
type = fown->pid_type;
pid = fown->pid;
if (!pid)
goto out_unlock_fown;
if (type <= PIDTYPE_TGID) {
rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (p)
send_sigio_to_task(p, fown, fd, band, type);
rcu_read_unlock();
} else {
read_lock(&tasklist_lock);
do_each_pid_task(pid, type, p) {
send_sigio_to_task(p, fown, fd, band, type);
} while_each_pid_task(pid, type, p);
read_unlock(&tasklist_lock);
}
out_unlock_fown:
read_unlock_irqrestore(&fown->lock, flags);
}
static void send_sigurg_to_task(struct task_struct *p,
struct fown_struct *fown, enum pid_type type)
{
if (sigio_perm(p, fown, SIGURG))
do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type);
}
int send_sigurg(struct fown_struct *fown)
{
struct task_struct *p;
enum pid_type type;
struct pid *pid;
unsigned long flags;
int ret = 0;
read_lock_irqsave(&fown->lock, flags);
type = fown->pid_type;
pid = fown->pid;
if (!pid)
goto out_unlock_fown;
ret = 1;
if (type <= PIDTYPE_TGID) {
rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (p)
send_sigurg_to_task(p, fown, type);
rcu_read_unlock();
} else {
read_lock(&tasklist_lock);
do_each_pid_task(pid, type, p) {
send_sigurg_to_task(p, fown, type);
} while_each_pid_task(pid, type, p);
read_unlock(&tasklist_lock);
}
out_unlock_fown:
read_unlock_irqrestore(&fown->lock, flags);
return ret;
}
static DEFINE_SPINLOCK(fasync_lock);
static struct kmem_cache *fasync_cache __read_mostly;
static void fasync_free_rcu(struct rcu_head *head)
{
kmem_cache_free(fasync_cache,
container_of(head, struct fasync_struct, fa_rcu));
}
/*
* Remove a fasync entry. If successfully removed, return
* positive and clear the FASYNC flag. If no entry exists,
* do nothing and return 0.
*
* NOTE! It is very important that the FASYNC flag always
* match the state "is the filp on a fasync list".
*
*/
int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
{
struct fasync_struct *fa, **fp;
int result = 0;
spin_lock(&filp->f_lock);
spin_lock(&fasync_lock);
for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
if (fa->fa_file != filp)
continue;
write_lock_irq(&fa->fa_lock);
fa->fa_file = NULL;
write_unlock_irq(&fa->fa_lock);
*fp = fa->fa_next;
call_rcu(&fa->fa_rcu, fasync_free_rcu);
filp->f_flags &= ~FASYNC;
result = 1;
break;
}
spin_unlock(&fasync_lock);
spin_unlock(&filp->f_lock);
return result;
}
struct fasync_struct *fasync_alloc(void)
{
return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
}
/*
* NOTE! This can be used only for unused fasync entries:
* entries that actually got inserted on the fasync list
* need to be released by rcu - see fasync_remove_entry.
*/
void fasync_free(struct fasync_struct *new)
{
kmem_cache_free(fasync_cache, new);
}
/*
* Insert a new entry into the fasync list. Return the pointer to the
* old one if we didn't use the new one.
*
* NOTE! It is very important that the FASYNC flag always
* match the state "is the filp on a fasync list".
*/
struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
{
struct fasync_struct *fa, **fp;
spin_lock(&filp->f_lock);
spin_lock(&fasync_lock);
for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
if (fa->fa_file != filp)
continue;
write_lock_irq(&fa->fa_lock);
fa->fa_fd = fd;
write_unlock_irq(&fa->fa_lock);
goto out;
}
rwlock_init(&new->fa_lock);
new->magic = FASYNC_MAGIC;
new->fa_file = filp;
new->fa_fd = fd;
new->fa_next = *fapp;
rcu_assign_pointer(*fapp, new);
filp->f_flags |= FASYNC;
out:
spin_unlock(&fasync_lock);
spin_unlock(&filp->f_lock);
return fa;
}
/*
* Add a fasync entry. Return negative on error, positive if
* added, and zero if did nothing but change an existing one.
*/
static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
{
struct fasync_struct *new;
new = fasync_alloc();
if (!new)
return -ENOMEM;
/*
* fasync_insert_entry() returns the old (update) entry if
* it existed.
*
* So free the (unused) new entry and return 0 to let the
* caller know that we didn't add any new fasync entries.
*/
if (fasync_insert_entry(fd, filp, fapp, new)) {
fasync_free(new);
return 0;
}
return 1;
}
/*
* fasync_helper() is used by almost all character device drivers
* to set up the fasync queue, and for regular files by the file
* lease code. It returns negative on error, 0 if it did no changes
* and positive if it added/deleted the entry.
*/
int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
{
if (!on)
return fasync_remove_entry(filp, fapp);
return fasync_add_entry(fd, filp, fapp);
}
EXPORT_SYMBOL(fasync_helper);
/*
* rcu_read_lock() is held
*/
static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
{
while (fa) {
struct fown_struct *fown;
unsigned long flags;
if (fa->magic != FASYNC_MAGIC) {
printk(KERN_ERR "kill_fasync: bad magic number in "
"fasync_struct!\n");
return;
}
read_lock_irqsave(&fa->fa_lock, flags);
if (fa->fa_file) {
fown = &fa->fa_file->f_owner;
/* Don't send SIGURG to processes which have not set a
queued signum: SIGURG has its own default signalling
mechanism. */
if (!(sig == SIGURG && fown->signum == 0))
send_sigio(fown, fa->fa_fd, band);
}
read_unlock_irqrestore(&fa->fa_lock, flags);
fa = rcu_dereference(fa->fa_next);
}
}
void kill_fasync(struct fasync_struct **fp, int sig, int band)
{
/* First a quick test without locking: usually
* the list is empty.
*/
if (*fp) {
rcu_read_lock();
kill_fasync_rcu(rcu_dereference(*fp), sig, band);
rcu_read_unlock();
}
}
EXPORT_SYMBOL(kill_fasync);
static int __init fcntl_init(void)
{
/*
* Please add new bits here to ensure allocation uniqueness.
* Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
* is defined as O_NONBLOCK on some platforms and not on others.
*/
BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
HWEIGHT32(
(VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
__FMODE_EXEC | __FMODE_NONOTIFY));
fasync_cache = kmem_cache_create("fasync_cache",
sizeof(struct fasync_struct), 0,
SLAB_PANIC | SLAB_ACCOUNT, NULL);
return 0;
}
module_init(fcntl_init)
| linux-master | fs/fcntl.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/mount.h>
#include <linux/pseudo_fs.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/proc_ns.h>
#include <linux/magic.h>
#include <linux/ktime.h>
#include <linux/seq_file.h>
#include <linux/user_namespace.h>
#include <linux/nsfs.h>
#include <linux/uaccess.h>
#include "internal.h"
static struct vfsmount *nsfs_mnt;
static long ns_ioctl(struct file *filp, unsigned int ioctl,
unsigned long arg);
static const struct file_operations ns_file_operations = {
.llseek = no_llseek,
.unlocked_ioctl = ns_ioctl,
.compat_ioctl = compat_ptr_ioctl,
};
static char *ns_dname(struct dentry *dentry, char *buffer, int buflen)
{
struct inode *inode = d_inode(dentry);
const struct proc_ns_operations *ns_ops = dentry->d_fsdata;
return dynamic_dname(buffer, buflen, "%s:[%lu]",
ns_ops->name, inode->i_ino);
}
static void ns_prune_dentry(struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
if (inode) {
struct ns_common *ns = inode->i_private;
atomic_long_set(&ns->stashed, 0);
}
}
const struct dentry_operations ns_dentry_operations =
{
.d_prune = ns_prune_dentry,
.d_delete = always_delete_dentry,
.d_dname = ns_dname,
};
static void nsfs_evict(struct inode *inode)
{
struct ns_common *ns = inode->i_private;
clear_inode(inode);
ns->ops->put(ns);
}
static int __ns_get_path(struct path *path, struct ns_common *ns)
{
struct vfsmount *mnt = nsfs_mnt;
struct dentry *dentry;
struct inode *inode;
unsigned long d;
rcu_read_lock();
d = atomic_long_read(&ns->stashed);
if (!d)
goto slow;
dentry = (struct dentry *)d;
if (!lockref_get_not_dead(&dentry->d_lockref))
goto slow;
rcu_read_unlock();
ns->ops->put(ns);
got_it:
path->mnt = mntget(mnt);
path->dentry = dentry;
return 0;
slow:
rcu_read_unlock();
inode = new_inode_pseudo(mnt->mnt_sb);
if (!inode) {
ns->ops->put(ns);
return -ENOMEM;
}
inode->i_ino = ns->inum;
inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode);
inode->i_flags |= S_IMMUTABLE;
inode->i_mode = S_IFREG | S_IRUGO;
inode->i_fop = &ns_file_operations;
inode->i_private = ns;
dentry = d_alloc_anon(mnt->mnt_sb);
if (!dentry) {
iput(inode);
return -ENOMEM;
}
d_instantiate(dentry, inode);
dentry->d_fsdata = (void *)ns->ops;
d = atomic_long_cmpxchg(&ns->stashed, 0, (unsigned long)dentry);
if (d) {
d_delete(dentry); /* make sure ->d_prune() does nothing */
dput(dentry);
cpu_relax();
return -EAGAIN;
}
goto got_it;
}
int ns_get_path_cb(struct path *path, ns_get_path_helper_t *ns_get_cb,
void *private_data)
{
int ret;
do {
struct ns_common *ns = ns_get_cb(private_data);
if (!ns)
return -ENOENT;
ret = __ns_get_path(path, ns);
} while (ret == -EAGAIN);
return ret;
}
struct ns_get_path_task_args {
const struct proc_ns_operations *ns_ops;
struct task_struct *task;
};
static struct ns_common *ns_get_path_task(void *private_data)
{
struct ns_get_path_task_args *args = private_data;
return args->ns_ops->get(args->task);
}
int ns_get_path(struct path *path, struct task_struct *task,
const struct proc_ns_operations *ns_ops)
{
struct ns_get_path_task_args args = {
.ns_ops = ns_ops,
.task = task,
};
return ns_get_path_cb(path, ns_get_path_task, &args);
}
int open_related_ns(struct ns_common *ns,
struct ns_common *(*get_ns)(struct ns_common *ns))
{
struct path path = {};
struct file *f;
int err;
int fd;
fd = get_unused_fd_flags(O_CLOEXEC);
if (fd < 0)
return fd;
do {
struct ns_common *relative;
relative = get_ns(ns);
if (IS_ERR(relative)) {
put_unused_fd(fd);
return PTR_ERR(relative);
}
err = __ns_get_path(&path, relative);
} while (err == -EAGAIN);
if (err) {
put_unused_fd(fd);
return err;
}
f = dentry_open(&path, O_RDONLY, current_cred());
path_put(&path);
if (IS_ERR(f)) {
put_unused_fd(fd);
fd = PTR_ERR(f);
} else
fd_install(fd, f);
return fd;
}
EXPORT_SYMBOL_GPL(open_related_ns);
static long ns_ioctl(struct file *filp, unsigned int ioctl,
unsigned long arg)
{
struct user_namespace *user_ns;
struct ns_common *ns = get_proc_ns(file_inode(filp));
uid_t __user *argp;
uid_t uid;
switch (ioctl) {
case NS_GET_USERNS:
return open_related_ns(ns, ns_get_owner);
case NS_GET_PARENT:
if (!ns->ops->get_parent)
return -EINVAL;
return open_related_ns(ns, ns->ops->get_parent);
case NS_GET_NSTYPE:
return ns->ops->type;
case NS_GET_OWNER_UID:
if (ns->ops->type != CLONE_NEWUSER)
return -EINVAL;
user_ns = container_of(ns, struct user_namespace, ns);
argp = (uid_t __user *) arg;
uid = from_kuid_munged(current_user_ns(), user_ns->owner);
return put_user(uid, argp);
default:
return -ENOTTY;
}
}
int ns_get_name(char *buf, size_t size, struct task_struct *task,
const struct proc_ns_operations *ns_ops)
{
struct ns_common *ns;
int res = -ENOENT;
const char *name;
ns = ns_ops->get(task);
if (ns) {
name = ns_ops->real_ns_name ? : ns_ops->name;
res = snprintf(buf, size, "%s:[%u]", name, ns->inum);
ns_ops->put(ns);
}
return res;
}
bool proc_ns_file(const struct file *file)
{
return file->f_op == &ns_file_operations;
}
/**
* ns_match() - Returns true if current namespace matches dev/ino provided.
* @ns: current namespace
* @dev: dev_t from nsfs that will be matched against current nsfs
* @ino: ino_t from nsfs that will be matched against current nsfs
*
* Return: true if dev and ino matches the current nsfs.
*/
bool ns_match(const struct ns_common *ns, dev_t dev, ino_t ino)
{
return (ns->inum == ino) && (nsfs_mnt->mnt_sb->s_dev == dev);
}
static int nsfs_show_path(struct seq_file *seq, struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
const struct proc_ns_operations *ns_ops = dentry->d_fsdata;
seq_printf(seq, "%s:[%lu]", ns_ops->name, inode->i_ino);
return 0;
}
static const struct super_operations nsfs_ops = {
.statfs = simple_statfs,
.evict_inode = nsfs_evict,
.show_path = nsfs_show_path,
};
static int nsfs_init_fs_context(struct fs_context *fc)
{
struct pseudo_fs_context *ctx = init_pseudo(fc, NSFS_MAGIC);
if (!ctx)
return -ENOMEM;
ctx->ops = &nsfs_ops;
ctx->dops = &ns_dentry_operations;
return 0;
}
static struct file_system_type nsfs = {
.name = "nsfs",
.init_fs_context = nsfs_init_fs_context,
.kill_sb = kill_anon_super,
};
void __init nsfs_init(void)
{
nsfs_mnt = kern_mount(&nsfs);
if (IS_ERR(nsfs_mnt))
panic("can't set nsfs up\n");
nsfs_mnt->mnt_sb->s_flags &= ~SB_NOUSER;
}
| linux-master | fs/nsfs.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/file.c
*
* Copyright (C) 1998-1999, Stephen Tweedie and Bill Hawes
*
* Manage the dynamic fd arrays in the process files_struct.
*/
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/close_range.h>
#include <net/sock.h>
#include "internal.h"
unsigned int sysctl_nr_open __read_mostly = 1024*1024;
unsigned int sysctl_nr_open_min = BITS_PER_LONG;
/* our min() is unusable in constant expressions ;-/ */
#define __const_min(x, y) ((x) < (y) ? (x) : (y))
unsigned int sysctl_nr_open_max =
__const_min(INT_MAX, ~(size_t)0/sizeof(void *)) & -BITS_PER_LONG;
static void __free_fdtable(struct fdtable *fdt)
{
kvfree(fdt->fd);
kvfree(fdt->open_fds);
kfree(fdt);
}
static void free_fdtable_rcu(struct rcu_head *rcu)
{
__free_fdtable(container_of(rcu, struct fdtable, rcu));
}
#define BITBIT_NR(nr) BITS_TO_LONGS(BITS_TO_LONGS(nr))
#define BITBIT_SIZE(nr) (BITBIT_NR(nr) * sizeof(long))
/*
* Copy 'count' fd bits from the old table to the new table and clear the extra
* space if any. This does not copy the file pointers. Called with the files
* spinlock held for write.
*/
static void copy_fd_bitmaps(struct fdtable *nfdt, struct fdtable *ofdt,
unsigned int count)
{
unsigned int cpy, set;
cpy = count / BITS_PER_BYTE;
set = (nfdt->max_fds - count) / BITS_PER_BYTE;
memcpy(nfdt->open_fds, ofdt->open_fds, cpy);
memset((char *)nfdt->open_fds + cpy, 0, set);
memcpy(nfdt->close_on_exec, ofdt->close_on_exec, cpy);
memset((char *)nfdt->close_on_exec + cpy, 0, set);
cpy = BITBIT_SIZE(count);
set = BITBIT_SIZE(nfdt->max_fds) - cpy;
memcpy(nfdt->full_fds_bits, ofdt->full_fds_bits, cpy);
memset((char *)nfdt->full_fds_bits + cpy, 0, set);
}
/*
* Copy all file descriptors from the old table to the new, expanded table and
* clear the extra space. Called with the files spinlock held for write.
*/
static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)
{
size_t cpy, set;
BUG_ON(nfdt->max_fds < ofdt->max_fds);
cpy = ofdt->max_fds * sizeof(struct file *);
set = (nfdt->max_fds - ofdt->max_fds) * sizeof(struct file *);
memcpy(nfdt->fd, ofdt->fd, cpy);
memset((char *)nfdt->fd + cpy, 0, set);
copy_fd_bitmaps(nfdt, ofdt, ofdt->max_fds);
}
/*
* Note how the fdtable bitmap allocations very much have to be a multiple of
* BITS_PER_LONG. This is not only because we walk those things in chunks of
* 'unsigned long' in some places, but simply because that is how the Linux
* kernel bitmaps are defined to work: they are not "bits in an array of bytes",
* they are very much "bits in an array of unsigned long".
*
* The ALIGN(nr, BITS_PER_LONG) here is for clarity: since we just multiplied
* by that "1024/sizeof(ptr)" before, we already know there are sufficient
* clear low bits. Clang seems to realize that, gcc ends up being confused.
*
* On a 128-bit machine, the ALIGN() would actually matter. In the meantime,
* let's consider it documentation (and maybe a test-case for gcc to improve
* its code generation ;)
*/
static struct fdtable * alloc_fdtable(unsigned int nr)
{
struct fdtable *fdt;
void *data;
/*
* Figure out how many fds we actually want to support in this fdtable.
* Allocation steps are keyed to the size of the fdarray, since it
* grows far faster than any of the other dynamic data. We try to fit
* the fdarray into comfortable page-tuned chunks: starting at 1024B
* and growing in powers of two from there on.
*/
nr /= (1024 / sizeof(struct file *));
nr = roundup_pow_of_two(nr + 1);
nr *= (1024 / sizeof(struct file *));
nr = ALIGN(nr, BITS_PER_LONG);
/*
* Note that this can drive nr *below* what we had passed if sysctl_nr_open
* had been set lower between the check in expand_files() and here. Deal
* with that in caller, it's cheaper that way.
*
* We make sure that nr remains a multiple of BITS_PER_LONG - otherwise
* bitmaps handling below becomes unpleasant, to put it mildly...
*/
if (unlikely(nr > sysctl_nr_open))
nr = ((sysctl_nr_open - 1) | (BITS_PER_LONG - 1)) + 1;
fdt = kmalloc(sizeof(struct fdtable), GFP_KERNEL_ACCOUNT);
if (!fdt)
goto out;
fdt->max_fds = nr;
data = kvmalloc_array(nr, sizeof(struct file *), GFP_KERNEL_ACCOUNT);
if (!data)
goto out_fdt;
fdt->fd = data;
data = kvmalloc(max_t(size_t,
2 * nr / BITS_PER_BYTE + BITBIT_SIZE(nr), L1_CACHE_BYTES),
GFP_KERNEL_ACCOUNT);
if (!data)
goto out_arr;
fdt->open_fds = data;
data += nr / BITS_PER_BYTE;
fdt->close_on_exec = data;
data += nr / BITS_PER_BYTE;
fdt->full_fds_bits = data;
return fdt;
out_arr:
kvfree(fdt->fd);
out_fdt:
kfree(fdt);
out:
return NULL;
}
/*
* Expand the file descriptor table.
* This function will allocate a new fdtable and both fd array and fdset, of
* the given size.
* Return <0 error code on error; 1 on successful completion.
* The files->file_lock should be held on entry, and will be held on exit.
*/
static int expand_fdtable(struct files_struct *files, unsigned int nr)
__releases(files->file_lock)
__acquires(files->file_lock)
{
struct fdtable *new_fdt, *cur_fdt;
spin_unlock(&files->file_lock);
new_fdt = alloc_fdtable(nr);
/* make sure all fd_install() have seen resize_in_progress
* or have finished their rcu_read_lock_sched() section.
*/
if (atomic_read(&files->count) > 1)
synchronize_rcu();
spin_lock(&files->file_lock);
if (!new_fdt)
return -ENOMEM;
/*
* extremely unlikely race - sysctl_nr_open decreased between the check in
* caller and alloc_fdtable(). Cheaper to catch it here...
*/
if (unlikely(new_fdt->max_fds <= nr)) {
__free_fdtable(new_fdt);
return -EMFILE;
}
cur_fdt = files_fdtable(files);
BUG_ON(nr < cur_fdt->max_fds);
copy_fdtable(new_fdt, cur_fdt);
rcu_assign_pointer(files->fdt, new_fdt);
if (cur_fdt != &files->fdtab)
call_rcu(&cur_fdt->rcu, free_fdtable_rcu);
/* coupled with smp_rmb() in fd_install() */
smp_wmb();
return 1;
}
/*
* Expand files.
* This function will expand the file structures, if the requested size exceeds
* the current capacity and there is room for expansion.
* Return <0 error code on error; 0 when nothing done; 1 when files were
* expanded and execution may have blocked.
* The files->file_lock should be held on entry, and will be held on exit.
*/
static int expand_files(struct files_struct *files, unsigned int nr)
__releases(files->file_lock)
__acquires(files->file_lock)
{
struct fdtable *fdt;
int expanded = 0;
repeat:
fdt = files_fdtable(files);
/* Do we need to expand? */
if (nr < fdt->max_fds)
return expanded;
/* Can we expand? */
if (nr >= sysctl_nr_open)
return -EMFILE;
if (unlikely(files->resize_in_progress)) {
spin_unlock(&files->file_lock);
expanded = 1;
wait_event(files->resize_wait, !files->resize_in_progress);
spin_lock(&files->file_lock);
goto repeat;
}
/* All good, so we try */
files->resize_in_progress = true;
expanded = expand_fdtable(files, nr);
files->resize_in_progress = false;
wake_up_all(&files->resize_wait);
return expanded;
}
static inline void __set_close_on_exec(unsigned int fd, struct fdtable *fdt)
{
__set_bit(fd, fdt->close_on_exec);
}
static inline void __clear_close_on_exec(unsigned int fd, struct fdtable *fdt)
{
if (test_bit(fd, fdt->close_on_exec))
__clear_bit(fd, fdt->close_on_exec);
}
static inline void __set_open_fd(unsigned int fd, struct fdtable *fdt)
{
__set_bit(fd, fdt->open_fds);
fd /= BITS_PER_LONG;
if (!~fdt->open_fds[fd])
__set_bit(fd, fdt->full_fds_bits);
}
static inline void __clear_open_fd(unsigned int fd, struct fdtable *fdt)
{
__clear_bit(fd, fdt->open_fds);
__clear_bit(fd / BITS_PER_LONG, fdt->full_fds_bits);
}
static unsigned int count_open_files(struct fdtable *fdt)
{
unsigned int size = fdt->max_fds;
unsigned int i;
/* Find the last open fd */
for (i = size / BITS_PER_LONG; i > 0; ) {
if (fdt->open_fds[--i])
break;
}
i = (i + 1) * BITS_PER_LONG;
return i;
}
/*
* Note that a sane fdtable size always has to be a multiple of
* BITS_PER_LONG, since we have bitmaps that are sized by this.
*
* 'max_fds' will normally already be properly aligned, but it
* turns out that in the close_range() -> __close_range() ->
* unshare_fd() -> dup_fd() -> sane_fdtable_size() we can end
* up having a 'max_fds' value that isn't already aligned.
*
* Rather than make close_range() have to worry about this,
* just make that BITS_PER_LONG alignment be part of a sane
* fdtable size. Becuase that's really what it is.
*/
static unsigned int sane_fdtable_size(struct fdtable *fdt, unsigned int max_fds)
{
unsigned int count;
count = count_open_files(fdt);
if (max_fds < NR_OPEN_DEFAULT)
max_fds = NR_OPEN_DEFAULT;
return ALIGN(min(count, max_fds), BITS_PER_LONG);
}
/*
* Allocate a new files structure and copy contents from the
* passed in files structure.
* errorp will be valid only when the returned files_struct is NULL.
*/
struct files_struct *dup_fd(struct files_struct *oldf, unsigned int max_fds, int *errorp)
{
struct files_struct *newf;
struct file **old_fds, **new_fds;
unsigned int open_files, i;
struct fdtable *old_fdt, *new_fdt;
*errorp = -ENOMEM;
newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
if (!newf)
goto out;
atomic_set(&newf->count, 1);
spin_lock_init(&newf->file_lock);
newf->resize_in_progress = false;
init_waitqueue_head(&newf->resize_wait);
newf->next_fd = 0;
new_fdt = &newf->fdtab;
new_fdt->max_fds = NR_OPEN_DEFAULT;
new_fdt->close_on_exec = newf->close_on_exec_init;
new_fdt->open_fds = newf->open_fds_init;
new_fdt->full_fds_bits = newf->full_fds_bits_init;
new_fdt->fd = &newf->fd_array[0];
spin_lock(&oldf->file_lock);
old_fdt = files_fdtable(oldf);
open_files = sane_fdtable_size(old_fdt, max_fds);
/*
* Check whether we need to allocate a larger fd array and fd set.
*/
while (unlikely(open_files > new_fdt->max_fds)) {
spin_unlock(&oldf->file_lock);
if (new_fdt != &newf->fdtab)
__free_fdtable(new_fdt);
new_fdt = alloc_fdtable(open_files - 1);
if (!new_fdt) {
*errorp = -ENOMEM;
goto out_release;
}
/* beyond sysctl_nr_open; nothing to do */
if (unlikely(new_fdt->max_fds < open_files)) {
__free_fdtable(new_fdt);
*errorp = -EMFILE;
goto out_release;
}
/*
* Reacquire the oldf lock and a pointer to its fd table
* who knows it may have a new bigger fd table. We need
* the latest pointer.
*/
spin_lock(&oldf->file_lock);
old_fdt = files_fdtable(oldf);
open_files = sane_fdtable_size(old_fdt, max_fds);
}
copy_fd_bitmaps(new_fdt, old_fdt, open_files);
old_fds = old_fdt->fd;
new_fds = new_fdt->fd;
for (i = open_files; i != 0; i--) {
struct file *f = *old_fds++;
if (f) {
get_file(f);
} else {
/*
* The fd may be claimed in the fd bitmap but not yet
* instantiated in the files array if a sibling thread
* is partway through open(). So make sure that this
* fd is available to the new process.
*/
__clear_open_fd(open_files - i, new_fdt);
}
rcu_assign_pointer(*new_fds++, f);
}
spin_unlock(&oldf->file_lock);
/* clear the remainder */
memset(new_fds, 0, (new_fdt->max_fds - open_files) * sizeof(struct file *));
rcu_assign_pointer(newf->fdt, new_fdt);
return newf;
out_release:
kmem_cache_free(files_cachep, newf);
out:
return NULL;
}
static struct fdtable *close_files(struct files_struct * files)
{
/*
* It is safe to dereference the fd table without RCU or
* ->file_lock because this is the last reference to the
* files structure.
*/
struct fdtable *fdt = rcu_dereference_raw(files->fdt);
unsigned int i, j = 0;
for (;;) {
unsigned long set;
i = j * BITS_PER_LONG;
if (i >= fdt->max_fds)
break;
set = fdt->open_fds[j++];
while (set) {
if (set & 1) {
struct file * file = xchg(&fdt->fd[i], NULL);
if (file) {
filp_close(file, files);
cond_resched();
}
}
i++;
set >>= 1;
}
}
return fdt;
}
void put_files_struct(struct files_struct *files)
{
if (atomic_dec_and_test(&files->count)) {
struct fdtable *fdt = close_files(files);
/* free the arrays if they are not embedded */
if (fdt != &files->fdtab)
__free_fdtable(fdt);
kmem_cache_free(files_cachep, files);
}
}
void exit_files(struct task_struct *tsk)
{
struct files_struct * files = tsk->files;
if (files) {
task_lock(tsk);
tsk->files = NULL;
task_unlock(tsk);
put_files_struct(files);
}
}
struct files_struct init_files = {
.count = ATOMIC_INIT(1),
.fdt = &init_files.fdtab,
.fdtab = {
.max_fds = NR_OPEN_DEFAULT,
.fd = &init_files.fd_array[0],
.close_on_exec = init_files.close_on_exec_init,
.open_fds = init_files.open_fds_init,
.full_fds_bits = init_files.full_fds_bits_init,
},
.file_lock = __SPIN_LOCK_UNLOCKED(init_files.file_lock),
.resize_wait = __WAIT_QUEUE_HEAD_INITIALIZER(init_files.resize_wait),
};
static unsigned int find_next_fd(struct fdtable *fdt, unsigned int start)
{
unsigned int maxfd = fdt->max_fds;
unsigned int maxbit = maxfd / BITS_PER_LONG;
unsigned int bitbit = start / BITS_PER_LONG;
bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG;
if (bitbit > maxfd)
return maxfd;
if (bitbit > start)
start = bitbit;
return find_next_zero_bit(fdt->open_fds, maxfd, start);
}
/*
* allocate a file descriptor, mark it busy.
*/
static int alloc_fd(unsigned start, unsigned end, unsigned flags)
{
struct files_struct *files = current->files;
unsigned int fd;
int error;
struct fdtable *fdt;
spin_lock(&files->file_lock);
repeat:
fdt = files_fdtable(files);
fd = start;
if (fd < files->next_fd)
fd = files->next_fd;
if (fd < fdt->max_fds)
fd = find_next_fd(fdt, fd);
/*
* N.B. For clone tasks sharing a files structure, this test
* will limit the total number of files that can be opened.
*/
error = -EMFILE;
if (fd >= end)
goto out;
error = expand_files(files, fd);
if (error < 0)
goto out;
/*
* If we needed to expand the fs array we
* might have blocked - try again.
*/
if (error)
goto repeat;
if (start <= files->next_fd)
files->next_fd = fd + 1;
__set_open_fd(fd, fdt);
if (flags & O_CLOEXEC)
__set_close_on_exec(fd, fdt);
else
__clear_close_on_exec(fd, fdt);
error = fd;
#if 1
/* Sanity check */
if (rcu_access_pointer(fdt->fd[fd]) != NULL) {
printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
rcu_assign_pointer(fdt->fd[fd], NULL);
}
#endif
out:
spin_unlock(&files->file_lock);
return error;
}
int __get_unused_fd_flags(unsigned flags, unsigned long nofile)
{
return alloc_fd(0, nofile, flags);
}
int get_unused_fd_flags(unsigned flags)
{
return __get_unused_fd_flags(flags, rlimit(RLIMIT_NOFILE));
}
EXPORT_SYMBOL(get_unused_fd_flags);
static void __put_unused_fd(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = files_fdtable(files);
__clear_open_fd(fd, fdt);
if (fd < files->next_fd)
files->next_fd = fd;
}
void put_unused_fd(unsigned int fd)
{
struct files_struct *files = current->files;
spin_lock(&files->file_lock);
__put_unused_fd(files, fd);
spin_unlock(&files->file_lock);
}
EXPORT_SYMBOL(put_unused_fd);
/*
* Install a file pointer in the fd array.
*
* The VFS is full of places where we drop the files lock between
* setting the open_fds bitmap and installing the file in the file
* array. At any such point, we are vulnerable to a dup2() race
* installing a file in the array before us. We need to detect this and
* fput() the struct file we are about to overwrite in this case.
*
* It should never happen - if we allow dup2() do it, _really_ bad things
* will follow.
*
* This consumes the "file" refcount, so callers should treat it
* as if they had called fput(file).
*/
void fd_install(unsigned int fd, struct file *file)
{
struct files_struct *files = current->files;
struct fdtable *fdt;
rcu_read_lock_sched();
if (unlikely(files->resize_in_progress)) {
rcu_read_unlock_sched();
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
BUG_ON(fdt->fd[fd] != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
spin_unlock(&files->file_lock);
return;
}
/* coupled with smp_wmb() in expand_fdtable() */
smp_rmb();
fdt = rcu_dereference_sched(files->fdt);
BUG_ON(fdt->fd[fd] != NULL);
rcu_assign_pointer(fdt->fd[fd], file);
rcu_read_unlock_sched();
}
EXPORT_SYMBOL(fd_install);
/**
* pick_file - return file associatd with fd
* @files: file struct to retrieve file from
* @fd: file descriptor to retrieve file for
*
* Context: files_lock must be held.
*
* Returns: The file associated with @fd (NULL if @fd is not open)
*/
static struct file *pick_file(struct files_struct *files, unsigned fd)
{
struct fdtable *fdt = files_fdtable(files);
struct file *file;
if (fd >= fdt->max_fds)
return NULL;
fd = array_index_nospec(fd, fdt->max_fds);
file = fdt->fd[fd];
if (file) {
rcu_assign_pointer(fdt->fd[fd], NULL);
__put_unused_fd(files, fd);
}
return file;
}
int close_fd(unsigned fd)
{
struct files_struct *files = current->files;
struct file *file;
spin_lock(&files->file_lock);
file = pick_file(files, fd);
spin_unlock(&files->file_lock);
if (!file)
return -EBADF;
return filp_close(file, files);
}
EXPORT_SYMBOL(close_fd); /* for ksys_close() */
/**
* last_fd - return last valid index into fd table
* @fdt: File descriptor table.
*
* Context: Either rcu read lock or files_lock must be held.
*
* Returns: Last valid index into fdtable.
*/
static inline unsigned last_fd(struct fdtable *fdt)
{
return fdt->max_fds - 1;
}
static inline void __range_cloexec(struct files_struct *cur_fds,
unsigned int fd, unsigned int max_fd)
{
struct fdtable *fdt;
/* make sure we're using the correct maximum value */
spin_lock(&cur_fds->file_lock);
fdt = files_fdtable(cur_fds);
max_fd = min(last_fd(fdt), max_fd);
if (fd <= max_fd)
bitmap_set(fdt->close_on_exec, fd, max_fd - fd + 1);
spin_unlock(&cur_fds->file_lock);
}
static inline void __range_close(struct files_struct *files, unsigned int fd,
unsigned int max_fd)
{
struct file *file;
unsigned n;
spin_lock(&files->file_lock);
n = last_fd(files_fdtable(files));
max_fd = min(max_fd, n);
for (; fd <= max_fd; fd++) {
file = pick_file(files, fd);
if (file) {
spin_unlock(&files->file_lock);
filp_close(file, files);
cond_resched();
spin_lock(&files->file_lock);
} else if (need_resched()) {
spin_unlock(&files->file_lock);
cond_resched();
spin_lock(&files->file_lock);
}
}
spin_unlock(&files->file_lock);
}
/**
* __close_range() - Close all file descriptors in a given range.
*
* @fd: starting file descriptor to close
* @max_fd: last file descriptor to close
* @flags: CLOSE_RANGE flags.
*
* This closes a range of file descriptors. All file descriptors
* from @fd up to and including @max_fd are closed.
*/
int __close_range(unsigned fd, unsigned max_fd, unsigned int flags)
{
struct task_struct *me = current;
struct files_struct *cur_fds = me->files, *fds = NULL;
if (flags & ~(CLOSE_RANGE_UNSHARE | CLOSE_RANGE_CLOEXEC))
return -EINVAL;
if (fd > max_fd)
return -EINVAL;
if (flags & CLOSE_RANGE_UNSHARE) {
int ret;
unsigned int max_unshare_fds = NR_OPEN_MAX;
/*
* If the caller requested all fds to be made cloexec we always
* copy all of the file descriptors since they still want to
* use them.
*/
if (!(flags & CLOSE_RANGE_CLOEXEC)) {
/*
* If the requested range is greater than the current
* maximum, we're closing everything so only copy all
* file descriptors beneath the lowest file descriptor.
*/
rcu_read_lock();
if (max_fd >= last_fd(files_fdtable(cur_fds)))
max_unshare_fds = fd;
rcu_read_unlock();
}
ret = unshare_fd(CLONE_FILES, max_unshare_fds, &fds);
if (ret)
return ret;
/*
* We used to share our file descriptor table, and have now
* created a private one, make sure we're using it below.
*/
if (fds)
swap(cur_fds, fds);
}
if (flags & CLOSE_RANGE_CLOEXEC)
__range_cloexec(cur_fds, fd, max_fd);
else
__range_close(cur_fds, fd, max_fd);
if (fds) {
/*
* We're done closing the files we were supposed to. Time to install
* the new file descriptor table and drop the old one.
*/
task_lock(me);
me->files = cur_fds;
task_unlock(me);
put_files_struct(fds);
}
return 0;
}
/*
* See close_fd_get_file() below, this variant assumes current->files->file_lock
* is held.
*/
struct file *__close_fd_get_file(unsigned int fd)
{
return pick_file(current->files, fd);
}
/*
* variant of close_fd that gets a ref on the file for later fput.
* The caller must ensure that filp_close() called on the file.
*/
struct file *close_fd_get_file(unsigned int fd)
{
struct files_struct *files = current->files;
struct file *file;
spin_lock(&files->file_lock);
file = pick_file(files, fd);
spin_unlock(&files->file_lock);
return file;
}
void do_close_on_exec(struct files_struct *files)
{
unsigned i;
struct fdtable *fdt;
/* exec unshares first */
spin_lock(&files->file_lock);
for (i = 0; ; i++) {
unsigned long set;
unsigned fd = i * BITS_PER_LONG;
fdt = files_fdtable(files);
if (fd >= fdt->max_fds)
break;
set = fdt->close_on_exec[i];
if (!set)
continue;
fdt->close_on_exec[i] = 0;
for ( ; set ; fd++, set >>= 1) {
struct file *file;
if (!(set & 1))
continue;
file = fdt->fd[fd];
if (!file)
continue;
rcu_assign_pointer(fdt->fd[fd], NULL);
__put_unused_fd(files, fd);
spin_unlock(&files->file_lock);
filp_close(file, files);
cond_resched();
spin_lock(&files->file_lock);
}
}
spin_unlock(&files->file_lock);
}
static inline struct file *__fget_files_rcu(struct files_struct *files,
unsigned int fd, fmode_t mask)
{
for (;;) {
struct file *file;
struct fdtable *fdt = rcu_dereference_raw(files->fdt);
struct file __rcu **fdentry;
if (unlikely(fd >= fdt->max_fds))
return NULL;
fdentry = fdt->fd + array_index_nospec(fd, fdt->max_fds);
file = rcu_dereference_raw(*fdentry);
if (unlikely(!file))
return NULL;
if (unlikely(file->f_mode & mask))
return NULL;
/*
* Ok, we have a file pointer. However, because we do
* this all locklessly under RCU, we may be racing with
* that file being closed.
*
* Such a race can take two forms:
*
* (a) the file ref already went down to zero,
* and get_file_rcu() fails. Just try again:
*/
if (unlikely(!get_file_rcu(file)))
continue;
/*
* (b) the file table entry has changed under us.
* Note that we don't need to re-check the 'fdt->fd'
* pointer having changed, because it always goes
* hand-in-hand with 'fdt'.
*
* If so, we need to put our ref and try again.
*/
if (unlikely(rcu_dereference_raw(files->fdt) != fdt) ||
unlikely(rcu_dereference_raw(*fdentry) != file)) {
fput(file);
continue;
}
/*
* Ok, we have a ref to the file, and checked that it
* still exists.
*/
return file;
}
}
static struct file *__fget_files(struct files_struct *files, unsigned int fd,
fmode_t mask)
{
struct file *file;
rcu_read_lock();
file = __fget_files_rcu(files, fd, mask);
rcu_read_unlock();
return file;
}
static inline struct file *__fget(unsigned int fd, fmode_t mask)
{
return __fget_files(current->files, fd, mask);
}
struct file *fget(unsigned int fd)
{
return __fget(fd, FMODE_PATH);
}
EXPORT_SYMBOL(fget);
struct file *fget_raw(unsigned int fd)
{
return __fget(fd, 0);
}
EXPORT_SYMBOL(fget_raw);
struct file *fget_task(struct task_struct *task, unsigned int fd)
{
struct file *file = NULL;
task_lock(task);
if (task->files)
file = __fget_files(task->files, fd, 0);
task_unlock(task);
return file;
}
struct file *task_lookup_fd_rcu(struct task_struct *task, unsigned int fd)
{
/* Must be called with rcu_read_lock held */
struct files_struct *files;
struct file *file = NULL;
task_lock(task);
files = task->files;
if (files)
file = files_lookup_fd_rcu(files, fd);
task_unlock(task);
return file;
}
struct file *task_lookup_next_fd_rcu(struct task_struct *task, unsigned int *ret_fd)
{
/* Must be called with rcu_read_lock held */
struct files_struct *files;
unsigned int fd = *ret_fd;
struct file *file = NULL;
task_lock(task);
files = task->files;
if (files) {
for (; fd < files_fdtable(files)->max_fds; fd++) {
file = files_lookup_fd_rcu(files, fd);
if (file)
break;
}
}
task_unlock(task);
*ret_fd = fd;
return file;
}
EXPORT_SYMBOL(task_lookup_next_fd_rcu);
/*
* Lightweight file lookup - no refcnt increment if fd table isn't shared.
*
* You can use this instead of fget if you satisfy all of the following
* conditions:
* 1) You must call fput_light before exiting the syscall and returning control
* to userspace (i.e. you cannot remember the returned struct file * after
* returning to userspace).
* 2) You must not call filp_close on the returned struct file * in between
* calls to fget_light and fput_light.
* 3) You must not clone the current task in between the calls to fget_light
* and fput_light.
*
* The fput_needed flag returned by fget_light should be passed to the
* corresponding fput_light.
*/
static unsigned long __fget_light(unsigned int fd, fmode_t mask)
{
struct files_struct *files = current->files;
struct file *file;
/*
* If another thread is concurrently calling close_fd() followed
* by put_files_struct(), we must not observe the old table
* entry combined with the new refcount - otherwise we could
* return a file that is concurrently being freed.
*
* atomic_read_acquire() pairs with atomic_dec_and_test() in
* put_files_struct().
*/
if (atomic_read_acquire(&files->count) == 1) {
file = files_lookup_fd_raw(files, fd);
if (!file || unlikely(file->f_mode & mask))
return 0;
return (unsigned long)file;
} else {
file = __fget(fd, mask);
if (!file)
return 0;
return FDPUT_FPUT | (unsigned long)file;
}
}
unsigned long __fdget(unsigned int fd)
{
return __fget_light(fd, FMODE_PATH);
}
EXPORT_SYMBOL(__fdget);
unsigned long __fdget_raw(unsigned int fd)
{
return __fget_light(fd, 0);
}
/*
* Try to avoid f_pos locking. We only need it if the
* file is marked for FMODE_ATOMIC_POS, and it can be
* accessed multiple ways.
*
* Always do it for directories, because pidfd_getfd()
* can make a file accessible even if it otherwise would
* not be, and for directories this is a correctness
* issue, not a "POSIX requirement".
*/
static inline bool file_needs_f_pos_lock(struct file *file)
{
return (file->f_mode & FMODE_ATOMIC_POS) &&
(file_count(file) > 1 || file->f_op->iterate_shared);
}
unsigned long __fdget_pos(unsigned int fd)
{
unsigned long v = __fdget(fd);
struct file *file = (struct file *)(v & ~3);
if (file && file_needs_f_pos_lock(file)) {
v |= FDPUT_POS_UNLOCK;
mutex_lock(&file->f_pos_lock);
}
return v;
}
void __f_unlock_pos(struct file *f)
{
mutex_unlock(&f->f_pos_lock);
}
/*
* We only lock f_pos if we have threads or if the file might be
* shared with another process. In both cases we'll have an elevated
* file count (done either by fdget() or by fork()).
*/
void set_close_on_exec(unsigned int fd, int flag)
{
struct files_struct *files = current->files;
struct fdtable *fdt;
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
if (flag)
__set_close_on_exec(fd, fdt);
else
__clear_close_on_exec(fd, fdt);
spin_unlock(&files->file_lock);
}
bool get_close_on_exec(unsigned int fd)
{
struct files_struct *files = current->files;
struct fdtable *fdt;
bool res;
rcu_read_lock();
fdt = files_fdtable(files);
res = close_on_exec(fd, fdt);
rcu_read_unlock();
return res;
}
static int do_dup2(struct files_struct *files,
struct file *file, unsigned fd, unsigned flags)
__releases(&files->file_lock)
{
struct file *tofree;
struct fdtable *fdt;
/*
* We need to detect attempts to do dup2() over allocated but still
* not finished descriptor. NB: OpenBSD avoids that at the price of
* extra work in their equivalent of fget() - they insert struct
* file immediately after grabbing descriptor, mark it larval if
* more work (e.g. actual opening) is needed and make sure that
* fget() treats larval files as absent. Potentially interesting,
* but while extra work in fget() is trivial, locking implications
* and amount of surgery on open()-related paths in VFS are not.
* FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
* deadlocks in rather amusing ways, AFAICS. All of that is out of
* scope of POSIX or SUS, since neither considers shared descriptor
* tables and this condition does not arise without those.
*/
fdt = files_fdtable(files);
tofree = fdt->fd[fd];
if (!tofree && fd_is_open(fd, fdt))
goto Ebusy;
get_file(file);
rcu_assign_pointer(fdt->fd[fd], file);
__set_open_fd(fd, fdt);
if (flags & O_CLOEXEC)
__set_close_on_exec(fd, fdt);
else
__clear_close_on_exec(fd, fdt);
spin_unlock(&files->file_lock);
if (tofree)
filp_close(tofree, files);
return fd;
Ebusy:
spin_unlock(&files->file_lock);
return -EBUSY;
}
int replace_fd(unsigned fd, struct file *file, unsigned flags)
{
int err;
struct files_struct *files = current->files;
if (!file)
return close_fd(fd);
if (fd >= rlimit(RLIMIT_NOFILE))
return -EBADF;
spin_lock(&files->file_lock);
err = expand_files(files, fd);
if (unlikely(err < 0))
goto out_unlock;
return do_dup2(files, file, fd, flags);
out_unlock:
spin_unlock(&files->file_lock);
return err;
}
/**
* __receive_fd() - Install received file into file descriptor table
* @file: struct file that was received from another process
* @ufd: __user pointer to write new fd number to
* @o_flags: the O_* flags to apply to the new fd entry
*
* Installs a received file into the file descriptor table, with appropriate
* checks and count updates. Optionally writes the fd number to userspace, if
* @ufd is non-NULL.
*
* This helper handles its own reference counting of the incoming
* struct file.
*
* Returns newly install fd or -ve on error.
*/
int __receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
{
int new_fd;
int error;
error = security_file_receive(file);
if (error)
return error;
new_fd = get_unused_fd_flags(o_flags);
if (new_fd < 0)
return new_fd;
if (ufd) {
error = put_user(new_fd, ufd);
if (error) {
put_unused_fd(new_fd);
return error;
}
}
fd_install(new_fd, get_file(file));
__receive_sock(file);
return new_fd;
}
int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)
{
int error;
error = security_file_receive(file);
if (error)
return error;
error = replace_fd(new_fd, file, o_flags);
if (error)
return error;
__receive_sock(file);
return new_fd;
}
int receive_fd(struct file *file, unsigned int o_flags)
{
return __receive_fd(file, NULL, o_flags);
}
EXPORT_SYMBOL_GPL(receive_fd);
static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
{
int err = -EBADF;
struct file *file;
struct files_struct *files = current->files;
if ((flags & ~O_CLOEXEC) != 0)
return -EINVAL;
if (unlikely(oldfd == newfd))
return -EINVAL;
if (newfd >= rlimit(RLIMIT_NOFILE))
return -EBADF;
spin_lock(&files->file_lock);
err = expand_files(files, newfd);
file = files_lookup_fd_locked(files, oldfd);
if (unlikely(!file))
goto Ebadf;
if (unlikely(err < 0)) {
if (err == -EMFILE)
goto Ebadf;
goto out_unlock;
}
return do_dup2(files, file, newfd, flags);
Ebadf:
err = -EBADF;
out_unlock:
spin_unlock(&files->file_lock);
return err;
}
SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
{
return ksys_dup3(oldfd, newfd, flags);
}
SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
{
if (unlikely(newfd == oldfd)) { /* corner case */
struct files_struct *files = current->files;
int retval = oldfd;
rcu_read_lock();
if (!files_lookup_fd_rcu(files, oldfd))
retval = -EBADF;
rcu_read_unlock();
return retval;
}
return ksys_dup3(oldfd, newfd, 0);
}
SYSCALL_DEFINE1(dup, unsigned int, fildes)
{
int ret = -EBADF;
struct file *file = fget_raw(fildes);
if (file) {
ret = get_unused_fd_flags(0);
if (ret >= 0)
fd_install(ret, file);
else
fput(file);
}
return ret;
}
int f_dupfd(unsigned int from, struct file *file, unsigned flags)
{
unsigned long nofile = rlimit(RLIMIT_NOFILE);
int err;
if (from >= nofile)
return -EINVAL;
err = alloc_fd(from, nofile, flags);
if (err >= 0) {
get_file(file);
fd_install(err, file);
}
return err;
}
int iterate_fd(struct files_struct *files, unsigned n,
int (*f)(const void *, struct file *, unsigned),
const void *p)
{
struct fdtable *fdt;
int res = 0;
if (!files)
return 0;
spin_lock(&files->file_lock);
for (fdt = files_fdtable(files); n < fdt->max_fds; n++) {
struct file *file;
file = rcu_dereference_check_fdtable(files, fdt->fd[n]);
if (!file)
continue;
res = f(p, file, n);
if (res)
break;
}
spin_unlock(&files->file_lock);
return res;
}
EXPORT_SYMBOL(iterate_fd);
| linux-master | fs/file.c |
// SPDX-License-Identifier: GPL-2.0
/*
* fs/mpage.c
*
* Copyright (C) 2002, Linus Torvalds.
*
* Contains functions related to preparing and submitting BIOs which contain
* multiple pagecache pages.
*
* 15May2002 Andrew Morton
* Initial version
* 27Jun2002 [email protected]
* use bio_add_page() to build bio's just the right size
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/kdev_t.h>
#include <linux/gfp.h>
#include <linux/bio.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/highmem.h>
#include <linux/prefetch.h>
#include <linux/mpage.h>
#include <linux/mm_inline.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
#include "internal.h"
/*
* I/O completion handler for multipage BIOs.
*
* The mpage code never puts partial pages into a BIO (except for end-of-file).
* If a page does not map to a contiguous run of blocks then it simply falls
* back to block_read_full_folio().
*
* Why is this? If a page's completion depends on a number of different BIOs
* which can complete in any order (or at the same time) then determining the
* status of that page is hard. See end_buffer_async_read() for the details.
* There is no point in duplicating all that complexity.
*/
static void mpage_read_end_io(struct bio *bio)
{
struct folio_iter fi;
int err = blk_status_to_errno(bio->bi_status);
bio_for_each_folio_all(fi, bio) {
if (err)
folio_set_error(fi.folio);
else
folio_mark_uptodate(fi.folio);
folio_unlock(fi.folio);
}
bio_put(bio);
}
static void mpage_write_end_io(struct bio *bio)
{
struct folio_iter fi;
int err = blk_status_to_errno(bio->bi_status);
bio_for_each_folio_all(fi, bio) {
if (err) {
folio_set_error(fi.folio);
mapping_set_error(fi.folio->mapping, err);
}
folio_end_writeback(fi.folio);
}
bio_put(bio);
}
static struct bio *mpage_bio_submit_read(struct bio *bio)
{
bio->bi_end_io = mpage_read_end_io;
guard_bio_eod(bio);
submit_bio(bio);
return NULL;
}
static struct bio *mpage_bio_submit_write(struct bio *bio)
{
bio->bi_end_io = mpage_write_end_io;
guard_bio_eod(bio);
submit_bio(bio);
return NULL;
}
/*
* support function for mpage_readahead. The fs supplied get_block might
* return an up to date buffer. This is used to map that buffer into
* the page, which allows read_folio to avoid triggering a duplicate call
* to get_block.
*
* The idea is to avoid adding buffers to pages that don't already have
* them. So when the buffer is up to date and the page size == block size,
* this marks the page up to date instead of adding new buffers.
*/
static void map_buffer_to_folio(struct folio *folio, struct buffer_head *bh,
int page_block)
{
struct inode *inode = folio->mapping->host;
struct buffer_head *page_bh, *head;
int block = 0;
head = folio_buffers(folio);
if (!head) {
/*
* don't make any buffers if there is only one buffer on
* the folio and the folio just needs to be set up to date
*/
if (inode->i_blkbits == PAGE_SHIFT &&
buffer_uptodate(bh)) {
folio_mark_uptodate(folio);
return;
}
create_empty_buffers(&folio->page, i_blocksize(inode), 0);
head = folio_buffers(folio);
}
page_bh = head;
do {
if (block == page_block) {
page_bh->b_state = bh->b_state;
page_bh->b_bdev = bh->b_bdev;
page_bh->b_blocknr = bh->b_blocknr;
break;
}
page_bh = page_bh->b_this_page;
block++;
} while (page_bh != head);
}
struct mpage_readpage_args {
struct bio *bio;
struct folio *folio;
unsigned int nr_pages;
bool is_readahead;
sector_t last_block_in_bio;
struct buffer_head map_bh;
unsigned long first_logical_block;
get_block_t *get_block;
};
/*
* This is the worker routine which does all the work of mapping the disk
* blocks and constructs largest possible bios, submits them for IO if the
* blocks are not contiguous on the disk.
*
* We pass a buffer_head back and forth and use its buffer_mapped() flag to
* represent the validity of its disk mapping and to decide when to do the next
* get_block() call.
*/
static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
{
struct folio *folio = args->folio;
struct inode *inode = folio->mapping->host;
const unsigned blkbits = inode->i_blkbits;
const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
const unsigned blocksize = 1 << blkbits;
struct buffer_head *map_bh = &args->map_bh;
sector_t block_in_file;
sector_t last_block;
sector_t last_block_in_file;
sector_t blocks[MAX_BUF_PER_PAGE];
unsigned page_block;
unsigned first_hole = blocks_per_page;
struct block_device *bdev = NULL;
int length;
int fully_mapped = 1;
blk_opf_t opf = REQ_OP_READ;
unsigned nblocks;
unsigned relative_block;
gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL);
/* MAX_BUF_PER_PAGE, for example */
VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
if (args->is_readahead) {
opf |= REQ_RAHEAD;
gfp |= __GFP_NORETRY | __GFP_NOWARN;
}
if (folio_buffers(folio))
goto confused;
block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);
last_block = block_in_file + args->nr_pages * blocks_per_page;
last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
if (last_block > last_block_in_file)
last_block = last_block_in_file;
page_block = 0;
/*
* Map blocks using the result from the previous get_blocks call first.
*/
nblocks = map_bh->b_size >> blkbits;
if (buffer_mapped(map_bh) &&
block_in_file > args->first_logical_block &&
block_in_file < (args->first_logical_block + nblocks)) {
unsigned map_offset = block_in_file - args->first_logical_block;
unsigned last = nblocks - map_offset;
for (relative_block = 0; ; relative_block++) {
if (relative_block == last) {
clear_buffer_mapped(map_bh);
break;
}
if (page_block == blocks_per_page)
break;
blocks[page_block] = map_bh->b_blocknr + map_offset +
relative_block;
page_block++;
block_in_file++;
}
bdev = map_bh->b_bdev;
}
/*
* Then do more get_blocks calls until we are done with this folio.
*/
map_bh->b_folio = folio;
while (page_block < blocks_per_page) {
map_bh->b_state = 0;
map_bh->b_size = 0;
if (block_in_file < last_block) {
map_bh->b_size = (last_block-block_in_file) << blkbits;
if (args->get_block(inode, block_in_file, map_bh, 0))
goto confused;
args->first_logical_block = block_in_file;
}
if (!buffer_mapped(map_bh)) {
fully_mapped = 0;
if (first_hole == blocks_per_page)
first_hole = page_block;
page_block++;
block_in_file++;
continue;
}
/* some filesystems will copy data into the page during
* the get_block call, in which case we don't want to
* read it again. map_buffer_to_folio copies the data
* we just collected from get_block into the folio's buffers
* so read_folio doesn't have to repeat the get_block call
*/
if (buffer_uptodate(map_bh)) {
map_buffer_to_folio(folio, map_bh, page_block);
goto confused;
}
if (first_hole != blocks_per_page)
goto confused; /* hole -> non-hole */
/* Contiguous blocks? */
if (page_block && blocks[page_block-1] != map_bh->b_blocknr-1)
goto confused;
nblocks = map_bh->b_size >> blkbits;
for (relative_block = 0; ; relative_block++) {
if (relative_block == nblocks) {
clear_buffer_mapped(map_bh);
break;
} else if (page_block == blocks_per_page)
break;
blocks[page_block] = map_bh->b_blocknr+relative_block;
page_block++;
block_in_file++;
}
bdev = map_bh->b_bdev;
}
if (first_hole != blocks_per_page) {
folio_zero_segment(folio, first_hole << blkbits, PAGE_SIZE);
if (first_hole == 0) {
folio_mark_uptodate(folio);
folio_unlock(folio);
goto out;
}
} else if (fully_mapped) {
folio_set_mappedtodisk(folio);
}
/*
* This folio will go to BIO. Do we need to send this BIO off first?
*/
if (args->bio && (args->last_block_in_bio != blocks[0] - 1))
args->bio = mpage_bio_submit_read(args->bio);
alloc_new:
if (args->bio == NULL) {
args->bio = bio_alloc(bdev, bio_max_segs(args->nr_pages), opf,
gfp);
if (args->bio == NULL)
goto confused;
args->bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
}
length = first_hole << blkbits;
if (!bio_add_folio(args->bio, folio, length, 0)) {
args->bio = mpage_bio_submit_read(args->bio);
goto alloc_new;
}
relative_block = block_in_file - args->first_logical_block;
nblocks = map_bh->b_size >> blkbits;
if ((buffer_boundary(map_bh) && relative_block == nblocks) ||
(first_hole != blocks_per_page))
args->bio = mpage_bio_submit_read(args->bio);
else
args->last_block_in_bio = blocks[blocks_per_page - 1];
out:
return args->bio;
confused:
if (args->bio)
args->bio = mpage_bio_submit_read(args->bio);
if (!folio_test_uptodate(folio))
block_read_full_folio(folio, args->get_block);
else
folio_unlock(folio);
goto out;
}
/**
* mpage_readahead - start reads against pages
* @rac: Describes which pages to read.
* @get_block: The filesystem's block mapper function.
*
* This function walks the pages and the blocks within each page, building and
* emitting large BIOs.
*
* If anything unusual happens, such as:
*
* - encountering a page which has buffers
* - encountering a page which has a non-hole after a hole
* - encountering a page with non-contiguous blocks
*
* then this code just gives up and calls the buffer_head-based read function.
* It does handle a page which has holes at the end - that is a common case:
* the end-of-file on blocksize < PAGE_SIZE setups.
*
* BH_Boundary explanation:
*
* There is a problem. The mpage read code assembles several pages, gets all
* their disk mappings, and then submits them all. That's fine, but obtaining
* the disk mappings may require I/O. Reads of indirect blocks, for example.
*
* So an mpage read of the first 16 blocks of an ext2 file will cause I/O to be
* submitted in the following order:
*
* 12 0 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16
*
* because the indirect block has to be read to get the mappings of blocks
* 13,14,15,16. Obviously, this impacts performance.
*
* So what we do it to allow the filesystem's get_block() function to set
* BH_Boundary when it maps block 11. BH_Boundary says: mapping of the block
* after this one will require I/O against a block which is probably close to
* this one. So you should push what I/O you have currently accumulated.
*
* This all causes the disk requests to be issued in the correct order.
*/
void mpage_readahead(struct readahead_control *rac, get_block_t get_block)
{
struct folio *folio;
struct mpage_readpage_args args = {
.get_block = get_block,
.is_readahead = true,
};
while ((folio = readahead_folio(rac))) {
prefetchw(&folio->flags);
args.folio = folio;
args.nr_pages = readahead_count(rac);
args.bio = do_mpage_readpage(&args);
}
if (args.bio)
mpage_bio_submit_read(args.bio);
}
EXPORT_SYMBOL(mpage_readahead);
/*
* This isn't called much at all
*/
int mpage_read_folio(struct folio *folio, get_block_t get_block)
{
struct mpage_readpage_args args = {
.folio = folio,
.nr_pages = 1,
.get_block = get_block,
};
args.bio = do_mpage_readpage(&args);
if (args.bio)
mpage_bio_submit_read(args.bio);
return 0;
}
EXPORT_SYMBOL(mpage_read_folio);
/*
* Writing is not so simple.
*
* If the page has buffers then they will be used for obtaining the disk
* mapping. We only support pages which are fully mapped-and-dirty, with a
* special case for pages which are unmapped at the end: end-of-file.
*
* If the page has no buffers (preferred) then the page is mapped here.
*
* If all blocks are found to be contiguous then the page can go into the
* BIO. Otherwise fall back to the mapping's writepage().
*
* FIXME: This code wants an estimate of how many pages are still to be
* written, so it can intelligently allocate a suitably-sized BIO. For now,
* just allocate full-size (16-page) BIOs.
*/
struct mpage_data {
struct bio *bio;
sector_t last_block_in_bio;
get_block_t *get_block;
};
/*
* We have our BIO, so we can now mark the buffers clean. Make
* sure to only clean buffers which we know we'll be writing.
*/
static void clean_buffers(struct page *page, unsigned first_unmapped)
{
unsigned buffer_counter = 0;
struct buffer_head *bh, *head;
if (!page_has_buffers(page))
return;
head = page_buffers(page);
bh = head;
do {
if (buffer_counter++ == first_unmapped)
break;
clear_buffer_dirty(bh);
bh = bh->b_this_page;
} while (bh != head);
/*
* we cannot drop the bh if the page is not uptodate or a concurrent
* read_folio would fail to serialize with the bh and it would read from
* disk before we reach the platter.
*/
if (buffer_heads_over_limit && PageUptodate(page))
try_to_free_buffers(page_folio(page));
}
/*
* For situations where we want to clean all buffers attached to a page.
* We don't need to calculate how many buffers are attached to the page,
* we just need to specify a number larger than the maximum number of buffers.
*/
void clean_page_buffers(struct page *page)
{
clean_buffers(page, ~0U);
}
static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
void *data)
{
struct mpage_data *mpd = data;
struct bio *bio = mpd->bio;
struct address_space *mapping = folio->mapping;
struct inode *inode = mapping->host;
const unsigned blkbits = inode->i_blkbits;
const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
sector_t last_block;
sector_t block_in_file;
sector_t blocks[MAX_BUF_PER_PAGE];
unsigned page_block;
unsigned first_unmapped = blocks_per_page;
struct block_device *bdev = NULL;
int boundary = 0;
sector_t boundary_block = 0;
struct block_device *boundary_bdev = NULL;
size_t length;
struct buffer_head map_bh;
loff_t i_size = i_size_read(inode);
int ret = 0;
struct buffer_head *head = folio_buffers(folio);
if (head) {
struct buffer_head *bh = head;
/* If they're all mapped and dirty, do it */
page_block = 0;
do {
BUG_ON(buffer_locked(bh));
if (!buffer_mapped(bh)) {
/*
* unmapped dirty buffers are created by
* block_dirty_folio -> mmapped data
*/
if (buffer_dirty(bh))
goto confused;
if (first_unmapped == blocks_per_page)
first_unmapped = page_block;
continue;
}
if (first_unmapped != blocks_per_page)
goto confused; /* hole -> non-hole */
if (!buffer_dirty(bh) || !buffer_uptodate(bh))
goto confused;
if (page_block) {
if (bh->b_blocknr != blocks[page_block-1] + 1)
goto confused;
}
blocks[page_block++] = bh->b_blocknr;
boundary = buffer_boundary(bh);
if (boundary) {
boundary_block = bh->b_blocknr;
boundary_bdev = bh->b_bdev;
}
bdev = bh->b_bdev;
} while ((bh = bh->b_this_page) != head);
if (first_unmapped)
goto page_is_mapped;
/*
* Page has buffers, but they are all unmapped. The page was
* created by pagein or read over a hole which was handled by
* block_read_full_folio(). If this address_space is also
* using mpage_readahead then this can rarely happen.
*/
goto confused;
}
/*
* The page has no buffers: map it to disk
*/
BUG_ON(!folio_test_uptodate(folio));
block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);
/*
* Whole page beyond EOF? Skip allocating blocks to avoid leaking
* space.
*/
if (block_in_file >= (i_size + (1 << blkbits) - 1) >> blkbits)
goto page_is_mapped;
last_block = (i_size - 1) >> blkbits;
map_bh.b_folio = folio;
for (page_block = 0; page_block < blocks_per_page; ) {
map_bh.b_state = 0;
map_bh.b_size = 1 << blkbits;
if (mpd->get_block(inode, block_in_file, &map_bh, 1))
goto confused;
if (!buffer_mapped(&map_bh))
goto confused;
if (buffer_new(&map_bh))
clean_bdev_bh_alias(&map_bh);
if (buffer_boundary(&map_bh)) {
boundary_block = map_bh.b_blocknr;
boundary_bdev = map_bh.b_bdev;
}
if (page_block) {
if (map_bh.b_blocknr != blocks[page_block-1] + 1)
goto confused;
}
blocks[page_block++] = map_bh.b_blocknr;
boundary = buffer_boundary(&map_bh);
bdev = map_bh.b_bdev;
if (block_in_file == last_block)
break;
block_in_file++;
}
BUG_ON(page_block == 0);
first_unmapped = page_block;
page_is_mapped:
/* Don't bother writing beyond EOF, truncate will discard the folio */
if (folio_pos(folio) >= i_size)
goto confused;
length = folio_size(folio);
if (folio_pos(folio) + length > i_size) {
/*
* The page straddles i_size. It must be zeroed out on each
* and every writepage invocation because it may be mmapped.
* "A file is mapped in multiples of the page size. For a file
* that is not a multiple of the page size, the remaining memory
* is zeroed when mapped, and writes to that region are not
* written out to the file."
*/
length = i_size - folio_pos(folio);
folio_zero_segment(folio, length, folio_size(folio));
}
/*
* This page will go to BIO. Do we need to send this BIO off first?
*/
if (bio && mpd->last_block_in_bio != blocks[0] - 1)
bio = mpage_bio_submit_write(bio);
alloc_new:
if (bio == NULL) {
bio = bio_alloc(bdev, BIO_MAX_VECS,
REQ_OP_WRITE | wbc_to_write_flags(wbc),
GFP_NOFS);
bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
wbc_init_bio(wbc, bio);
}
/*
* Must try to add the page before marking the buffer clean or
* the confused fail path above (OOM) will be very confused when
* it finds all bh marked clean (i.e. it will not write anything)
*/
wbc_account_cgroup_owner(wbc, &folio->page, folio_size(folio));
length = first_unmapped << blkbits;
if (!bio_add_folio(bio, folio, length, 0)) {
bio = mpage_bio_submit_write(bio);
goto alloc_new;
}
clean_buffers(&folio->page, first_unmapped);
BUG_ON(folio_test_writeback(folio));
folio_start_writeback(folio);
folio_unlock(folio);
if (boundary || (first_unmapped != blocks_per_page)) {
bio = mpage_bio_submit_write(bio);
if (boundary_block) {
write_boundary_block(boundary_bdev,
boundary_block, 1 << blkbits);
}
} else {
mpd->last_block_in_bio = blocks[blocks_per_page - 1];
}
goto out;
confused:
if (bio)
bio = mpage_bio_submit_write(bio);
/*
* The caller has a ref on the inode, so *mapping is stable
*/
ret = block_write_full_page(&folio->page, mpd->get_block, wbc);
mapping_set_error(mapping, ret);
out:
mpd->bio = bio;
return ret;
}
/**
* mpage_writepages - walk the list of dirty pages of the given address space & writepage() all of them
* @mapping: address space structure to write
* @wbc: subtract the number of written pages from *@wbc->nr_to_write
* @get_block: the filesystem's block mapper function.
*
* This is a library function, which implements the writepages()
* address_space_operation.
*/
int
mpage_writepages(struct address_space *mapping,
struct writeback_control *wbc, get_block_t get_block)
{
struct mpage_data mpd = {
.get_block = get_block,
};
struct blk_plug plug;
int ret;
blk_start_plug(&plug);
ret = write_cache_pages(mapping, wbc, __mpage_writepage, &mpd);
if (mpd.bio)
mpage_bio_submit_write(mpd.bio);
blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(mpage_writepages);
| linux-master | fs/mpage.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/bad_inode.c
*
* Copyright (C) 1997, Stephen Tweedie
*
* Provide stub functions for unreadable inodes
*
* Fabian Frederick : August 2003 - All file operations assigned to EIO
*/
#include <linux/fs.h>
#include <linux/export.h>
#include <linux/stat.h>
#include <linux/time.h>
#include <linux/namei.h>
#include <linux/poll.h>
#include <linux/fiemap.h>
static int bad_file_open(struct inode *inode, struct file *filp)
{
return -EIO;
}
static const struct file_operations bad_file_ops =
{
.open = bad_file_open,
};
static int bad_inode_create(struct mnt_idmap *idmap,
struct inode *dir, struct dentry *dentry,
umode_t mode, bool excl)
{
return -EIO;
}
static struct dentry *bad_inode_lookup(struct inode *dir,
struct dentry *dentry, unsigned int flags)
{
return ERR_PTR(-EIO);
}
static int bad_inode_link (struct dentry *old_dentry, struct inode *dir,
struct dentry *dentry)
{
return -EIO;
}
static int bad_inode_unlink(struct inode *dir, struct dentry *dentry)
{
return -EIO;
}
static int bad_inode_symlink(struct mnt_idmap *idmap,
struct inode *dir, struct dentry *dentry,
const char *symname)
{
return -EIO;
}
static int bad_inode_mkdir(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode)
{
return -EIO;
}
static int bad_inode_rmdir (struct inode *dir, struct dentry *dentry)
{
return -EIO;
}
static int bad_inode_mknod(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, dev_t rdev)
{
return -EIO;
}
static int bad_inode_rename2(struct mnt_idmap *idmap,
struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
return -EIO;
}
static int bad_inode_readlink(struct dentry *dentry, char __user *buffer,
int buflen)
{
return -EIO;
}
static int bad_inode_permission(struct mnt_idmap *idmap,
struct inode *inode, int mask)
{
return -EIO;
}
static int bad_inode_getattr(struct mnt_idmap *idmap,
const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
return -EIO;
}
static int bad_inode_setattr(struct mnt_idmap *idmap,
struct dentry *direntry, struct iattr *attrs)
{
return -EIO;
}
static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
size_t buffer_size)
{
return -EIO;
}
static const char *bad_inode_get_link(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
return ERR_PTR(-EIO);
}
static struct posix_acl *bad_inode_get_acl(struct inode *inode, int type, bool rcu)
{
return ERR_PTR(-EIO);
}
static int bad_inode_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo, u64 start,
u64 len)
{
return -EIO;
}
static int bad_inode_update_time(struct inode *inode, int flags)
{
return -EIO;
}
static int bad_inode_atomic_open(struct inode *inode, struct dentry *dentry,
struct file *file, unsigned int open_flag,
umode_t create_mode)
{
return -EIO;
}
static int bad_inode_tmpfile(struct mnt_idmap *idmap,
struct inode *inode, struct file *file,
umode_t mode)
{
return -EIO;
}
static int bad_inode_set_acl(struct mnt_idmap *idmap,
struct dentry *dentry, struct posix_acl *acl,
int type)
{
return -EIO;
}
static const struct inode_operations bad_inode_ops =
{
.create = bad_inode_create,
.lookup = bad_inode_lookup,
.link = bad_inode_link,
.unlink = bad_inode_unlink,
.symlink = bad_inode_symlink,
.mkdir = bad_inode_mkdir,
.rmdir = bad_inode_rmdir,
.mknod = bad_inode_mknod,
.rename = bad_inode_rename2,
.readlink = bad_inode_readlink,
.permission = bad_inode_permission,
.getattr = bad_inode_getattr,
.setattr = bad_inode_setattr,
.listxattr = bad_inode_listxattr,
.get_link = bad_inode_get_link,
.get_inode_acl = bad_inode_get_acl,
.fiemap = bad_inode_fiemap,
.update_time = bad_inode_update_time,
.atomic_open = bad_inode_atomic_open,
.tmpfile = bad_inode_tmpfile,
.set_acl = bad_inode_set_acl,
};
/*
* When a filesystem is unable to read an inode due to an I/O error in
* its read_inode() function, it can call make_bad_inode() to return a
* set of stubs which will return EIO errors as required.
*
* We only need to do limited initialisation: all other fields are
* preinitialised to zero automatically.
*/
/**
* make_bad_inode - mark an inode bad due to an I/O error
* @inode: Inode to mark bad
*
* When an inode cannot be read due to a media or remote network
* failure this function makes the inode "bad" and causes I/O operations
* on it to fail from this point on.
*/
void make_bad_inode(struct inode *inode)
{
remove_inode_hash(inode);
inode->i_mode = S_IFREG;
inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
inode->i_op = &bad_inode_ops;
inode->i_opflags &= ~IOP_XATTR;
inode->i_fop = &bad_file_ops;
}
EXPORT_SYMBOL(make_bad_inode);
/*
* This tests whether an inode has been flagged as bad. The test uses
* &bad_inode_ops to cover the case of invalidated inodes as well as
* those created by make_bad_inode() above.
*/
/**
* is_bad_inode - is an inode errored
* @inode: inode to test
*
* Returns true if the inode in question has been marked as bad.
*/
bool is_bad_inode(struct inode *inode)
{
return (inode->i_op == &bad_inode_ops);
}
EXPORT_SYMBOL(is_bad_inode);
/**
* iget_failed - Mark an under-construction inode as dead and release it
* @inode: The inode to discard
*
* Mark an under-construction inode as dead and release it.
*/
void iget_failed(struct inode *inode)
{
make_bad_inode(inode);
unlock_new_inode(inode);
iput(inode);
}
EXPORT_SYMBOL(iget_failed);
| linux-master | fs/bad_inode.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* Filesystem access-by-fd.
*
* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/anon_inodes.h>
#include <linux/namei.h>
#include <linux/file.h>
#include <uapi/linux/mount.h>
#include "internal.h"
#include "mount.h"
/*
* Allow the user to read back any error, warning or informational messages.
*/
static ssize_t fscontext_read(struct file *file,
char __user *_buf, size_t len, loff_t *pos)
{
struct fs_context *fc = file->private_data;
struct fc_log *log = fc->log.log;
unsigned int logsize = ARRAY_SIZE(log->buffer);
ssize_t ret;
char *p;
bool need_free;
int index, n;
ret = mutex_lock_interruptible(&fc->uapi_mutex);
if (ret < 0)
return ret;
if (log->head == log->tail) {
mutex_unlock(&fc->uapi_mutex);
return -ENODATA;
}
index = log->tail & (logsize - 1);
p = log->buffer[index];
need_free = log->need_free & (1 << index);
log->buffer[index] = NULL;
log->need_free &= ~(1 << index);
log->tail++;
mutex_unlock(&fc->uapi_mutex);
ret = -EMSGSIZE;
n = strlen(p);
if (n > len)
goto err_free;
ret = -EFAULT;
if (copy_to_user(_buf, p, n) != 0)
goto err_free;
ret = n;
err_free:
if (need_free)
kfree(p);
return ret;
}
static int fscontext_release(struct inode *inode, struct file *file)
{
struct fs_context *fc = file->private_data;
if (fc) {
file->private_data = NULL;
put_fs_context(fc);
}
return 0;
}
const struct file_operations fscontext_fops = {
.read = fscontext_read,
.release = fscontext_release,
.llseek = no_llseek,
};
/*
* Attach a filesystem context to a file and an fd.
*/
static int fscontext_create_fd(struct fs_context *fc, unsigned int o_flags)
{
int fd;
fd = anon_inode_getfd("[fscontext]", &fscontext_fops, fc,
O_RDWR | o_flags);
if (fd < 0)
put_fs_context(fc);
return fd;
}
static int fscontext_alloc_log(struct fs_context *fc)
{
fc->log.log = kzalloc(sizeof(*fc->log.log), GFP_KERNEL);
if (!fc->log.log)
return -ENOMEM;
refcount_set(&fc->log.log->usage, 1);
fc->log.log->owner = fc->fs_type->owner;
return 0;
}
/*
* Open a filesystem by name so that it can be configured for mounting.
*
* We are allowed to specify a container in which the filesystem will be
* opened, thereby indicating which namespaces will be used (notably, which
* network namespace will be used for network filesystems).
*/
SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
{
struct file_system_type *fs_type;
struct fs_context *fc;
const char *fs_name;
int ret;
if (!may_mount())
return -EPERM;
if (flags & ~FSOPEN_CLOEXEC)
return -EINVAL;
fs_name = strndup_user(_fs_name, PAGE_SIZE);
if (IS_ERR(fs_name))
return PTR_ERR(fs_name);
fs_type = get_fs_type(fs_name);
kfree(fs_name);
if (!fs_type)
return -ENODEV;
fc = fs_context_for_mount(fs_type, 0);
put_filesystem(fs_type);
if (IS_ERR(fc))
return PTR_ERR(fc);
fc->phase = FS_CONTEXT_CREATE_PARAMS;
ret = fscontext_alloc_log(fc);
if (ret < 0)
goto err_fc;
return fscontext_create_fd(fc, flags & FSOPEN_CLOEXEC ? O_CLOEXEC : 0);
err_fc:
put_fs_context(fc);
return ret;
}
/*
* Pick a superblock into a context for reconfiguration.
*/
SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags)
{
struct fs_context *fc;
struct path target;
unsigned int lookup_flags;
int ret;
if (!may_mount())
return -EPERM;
if ((flags & ~(FSPICK_CLOEXEC |
FSPICK_SYMLINK_NOFOLLOW |
FSPICK_NO_AUTOMOUNT |
FSPICK_EMPTY_PATH)) != 0)
return -EINVAL;
lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
if (flags & FSPICK_SYMLINK_NOFOLLOW)
lookup_flags &= ~LOOKUP_FOLLOW;
if (flags & FSPICK_NO_AUTOMOUNT)
lookup_flags &= ~LOOKUP_AUTOMOUNT;
if (flags & FSPICK_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
ret = user_path_at(dfd, path, lookup_flags, &target);
if (ret < 0)
goto err;
ret = -EINVAL;
if (target.mnt->mnt_root != target.dentry)
goto err_path;
fc = fs_context_for_reconfigure(target.dentry, 0, 0);
if (IS_ERR(fc)) {
ret = PTR_ERR(fc);
goto err_path;
}
fc->phase = FS_CONTEXT_RECONF_PARAMS;
ret = fscontext_alloc_log(fc);
if (ret < 0)
goto err_fc;
path_put(&target);
return fscontext_create_fd(fc, flags & FSPICK_CLOEXEC ? O_CLOEXEC : 0);
err_fc:
put_fs_context(fc);
err_path:
path_put(&target);
err:
return ret;
}
static int vfs_cmd_create(struct fs_context *fc, bool exclusive)
{
struct super_block *sb;
int ret;
if (fc->phase != FS_CONTEXT_CREATE_PARAMS)
return -EBUSY;
if (!mount_capable(fc))
return -EPERM;
/* require the new mount api */
if (exclusive && fc->ops == &legacy_fs_context_ops)
return -EOPNOTSUPP;
fc->phase = FS_CONTEXT_CREATING;
fc->exclusive = exclusive;
ret = vfs_get_tree(fc);
if (ret) {
fc->phase = FS_CONTEXT_FAILED;
return ret;
}
sb = fc->root->d_sb;
ret = security_sb_kern_mount(sb);
if (unlikely(ret)) {
fc_drop_locked(fc);
fc->phase = FS_CONTEXT_FAILED;
return ret;
}
/* vfs_get_tree() callchains will have grabbed @s_umount */
up_write(&sb->s_umount);
fc->phase = FS_CONTEXT_AWAITING_MOUNT;
return 0;
}
static int vfs_cmd_reconfigure(struct fs_context *fc)
{
struct super_block *sb;
int ret;
if (fc->phase != FS_CONTEXT_RECONF_PARAMS)
return -EBUSY;
fc->phase = FS_CONTEXT_RECONFIGURING;
sb = fc->root->d_sb;
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
fc->phase = FS_CONTEXT_FAILED;
return -EPERM;
}
down_write(&sb->s_umount);
ret = reconfigure_super(fc);
up_write(&sb->s_umount);
if (ret) {
fc->phase = FS_CONTEXT_FAILED;
return ret;
}
vfs_clean_context(fc);
return 0;
}
/*
* Check the state and apply the configuration. Note that this function is
* allowed to 'steal' the value by setting param->xxx to NULL before returning.
*/
static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
struct fs_parameter *param)
{
int ret;
ret = finish_clean_context(fc);
if (ret)
return ret;
switch (cmd) {
case FSCONFIG_CMD_CREATE:
return vfs_cmd_create(fc, false);
case FSCONFIG_CMD_CREATE_EXCL:
return vfs_cmd_create(fc, true);
case FSCONFIG_CMD_RECONFIGURE:
return vfs_cmd_reconfigure(fc);
default:
if (fc->phase != FS_CONTEXT_CREATE_PARAMS &&
fc->phase != FS_CONTEXT_RECONF_PARAMS)
return -EBUSY;
return vfs_parse_fs_param(fc, param);
}
}
/**
* sys_fsconfig - Set parameters and trigger actions on a context
* @fd: The filesystem context to act upon
* @cmd: The action to take
* @_key: Where appropriate, the parameter key to set
* @_value: Where appropriate, the parameter value to set
* @aux: Additional information for the value
*
* This system call is used to set parameters on a context, including
* superblock settings, data source and security labelling.
*
* Actions include triggering the creation of a superblock and the
* reconfiguration of the superblock attached to the specified context.
*
* When setting a parameter, @cmd indicates the type of value being proposed
* and @_key indicates the parameter to be altered.
*
* @_value and @aux are used to specify the value, should a value be required:
*
* (*) fsconfig_set_flag: No value is specified. The parameter must be boolean
* in nature. The key may be prefixed with "no" to invert the
* setting. @_value must be NULL and @aux must be 0.
*
* (*) fsconfig_set_string: A string value is specified. The parameter can be
* expecting boolean, integer, string or take a path. A conversion to an
* appropriate type will be attempted (which may include looking up as a
* path). @_value points to a NUL-terminated string and @aux must be 0.
*
* (*) fsconfig_set_binary: A binary blob is specified. @_value points to the
* blob and @aux indicates its size. The parameter must be expecting a
* blob.
*
* (*) fsconfig_set_path: A non-empty path is specified. The parameter must be
* expecting a path object. @_value points to a NUL-terminated string that
* is the path and @aux is a file descriptor at which to start a relative
* lookup or AT_FDCWD.
*
* (*) fsconfig_set_path_empty: As fsconfig_set_path, but with AT_EMPTY_PATH
* implied.
*
* (*) fsconfig_set_fd: An open file descriptor is specified. @_value must be
* NULL and @aux indicates the file descriptor.
*/
SYSCALL_DEFINE5(fsconfig,
int, fd,
unsigned int, cmd,
const char __user *, _key,
const void __user *, _value,
int, aux)
{
struct fs_context *fc;
struct fd f;
int ret;
int lookup_flags = 0;
struct fs_parameter param = {
.type = fs_value_is_undefined,
};
if (fd < 0)
return -EINVAL;
switch (cmd) {
case FSCONFIG_SET_FLAG:
if (!_key || _value || aux)
return -EINVAL;
break;
case FSCONFIG_SET_STRING:
if (!_key || !_value || aux)
return -EINVAL;
break;
case FSCONFIG_SET_BINARY:
if (!_key || !_value || aux <= 0 || aux > 1024 * 1024)
return -EINVAL;
break;
case FSCONFIG_SET_PATH:
case FSCONFIG_SET_PATH_EMPTY:
if (!_key || !_value || (aux != AT_FDCWD && aux < 0))
return -EINVAL;
break;
case FSCONFIG_SET_FD:
if (!_key || _value || aux < 0)
return -EINVAL;
break;
case FSCONFIG_CMD_CREATE:
case FSCONFIG_CMD_CREATE_EXCL:
case FSCONFIG_CMD_RECONFIGURE:
if (_key || _value || aux)
return -EINVAL;
break;
default:
return -EOPNOTSUPP;
}
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -EINVAL;
if (f.file->f_op != &fscontext_fops)
goto out_f;
fc = f.file->private_data;
if (fc->ops == &legacy_fs_context_ops) {
switch (cmd) {
case FSCONFIG_SET_BINARY:
case FSCONFIG_SET_PATH:
case FSCONFIG_SET_PATH_EMPTY:
case FSCONFIG_SET_FD:
ret = -EOPNOTSUPP;
goto out_f;
}
}
if (_key) {
param.key = strndup_user(_key, 256);
if (IS_ERR(param.key)) {
ret = PTR_ERR(param.key);
goto out_f;
}
}
switch (cmd) {
case FSCONFIG_SET_FLAG:
param.type = fs_value_is_flag;
break;
case FSCONFIG_SET_STRING:
param.type = fs_value_is_string;
param.string = strndup_user(_value, 256);
if (IS_ERR(param.string)) {
ret = PTR_ERR(param.string);
goto out_key;
}
param.size = strlen(param.string);
break;
case FSCONFIG_SET_BINARY:
param.type = fs_value_is_blob;
param.size = aux;
param.blob = memdup_user_nul(_value, aux);
if (IS_ERR(param.blob)) {
ret = PTR_ERR(param.blob);
goto out_key;
}
break;
case FSCONFIG_SET_PATH_EMPTY:
lookup_flags = LOOKUP_EMPTY;
fallthrough;
case FSCONFIG_SET_PATH:
param.type = fs_value_is_filename;
param.name = getname_flags(_value, lookup_flags, NULL);
if (IS_ERR(param.name)) {
ret = PTR_ERR(param.name);
goto out_key;
}
param.dirfd = aux;
param.size = strlen(param.name->name);
break;
case FSCONFIG_SET_FD:
param.type = fs_value_is_file;
ret = -EBADF;
param.file = fget(aux);
if (!param.file)
goto out_key;
break;
default:
break;
}
ret = mutex_lock_interruptible(&fc->uapi_mutex);
if (ret == 0) {
ret = vfs_fsconfig_locked(fc, cmd, ¶m);
mutex_unlock(&fc->uapi_mutex);
}
/* Clean up the our record of any value that we obtained from
* userspace. Note that the value may have been stolen by the LSM or
* filesystem, in which case the value pointer will have been cleared.
*/
switch (cmd) {
case FSCONFIG_SET_STRING:
case FSCONFIG_SET_BINARY:
kfree(param.string);
break;
case FSCONFIG_SET_PATH:
case FSCONFIG_SET_PATH_EMPTY:
if (param.name)
putname(param.name);
break;
case FSCONFIG_SET_FD:
if (param.file)
fput(param.file);
break;
default:
break;
}
out_key:
kfree(param.key);
out_f:
fdput(f);
return ret;
}
| linux-master | fs/fsopen.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/fs.h>
#include <linux/export.h>
/*
* fs on-disk file type to dirent file type conversion
*/
static const unsigned char fs_dtype_by_ftype[FT_MAX] = {
[FT_UNKNOWN] = DT_UNKNOWN,
[FT_REG_FILE] = DT_REG,
[FT_DIR] = DT_DIR,
[FT_CHRDEV] = DT_CHR,
[FT_BLKDEV] = DT_BLK,
[FT_FIFO] = DT_FIFO,
[FT_SOCK] = DT_SOCK,
[FT_SYMLINK] = DT_LNK
};
/**
* fs_ftype_to_dtype() - fs on-disk file type to dirent type.
* @filetype: The on-disk file type to convert.
*
* This function converts the on-disk file type value (FT_*) to the directory
* entry type (DT_*).
*
* Context: Any context.
* Return:
* * DT_UNKNOWN - Unknown type
* * DT_FIFO - FIFO
* * DT_CHR - Character device
* * DT_DIR - Directory
* * DT_BLK - Block device
* * DT_REG - Regular file
* * DT_LNK - Symbolic link
* * DT_SOCK - Local-domain socket
*/
unsigned char fs_ftype_to_dtype(unsigned int filetype)
{
if (filetype >= FT_MAX)
return DT_UNKNOWN;
return fs_dtype_by_ftype[filetype];
}
EXPORT_SYMBOL_GPL(fs_ftype_to_dtype);
/*
* dirent file type to fs on-disk file type conversion
* Values not initialized explicitly are FT_UNKNOWN (0).
*/
static const unsigned char fs_ftype_by_dtype[DT_MAX] = {
[DT_REG] = FT_REG_FILE,
[DT_DIR] = FT_DIR,
[DT_LNK] = FT_SYMLINK,
[DT_CHR] = FT_CHRDEV,
[DT_BLK] = FT_BLKDEV,
[DT_FIFO] = FT_FIFO,
[DT_SOCK] = FT_SOCK,
};
/**
* fs_umode_to_ftype() - file mode to on-disk file type.
* @mode: The file mode to convert.
*
* This function converts the file mode value to the on-disk file type (FT_*).
*
* Context: Any context.
* Return:
* * FT_UNKNOWN - Unknown type
* * FT_REG_FILE - Regular file
* * FT_DIR - Directory
* * FT_CHRDEV - Character device
* * FT_BLKDEV - Block device
* * FT_FIFO - FIFO
* * FT_SOCK - Local-domain socket
* * FT_SYMLINK - Symbolic link
*/
unsigned char fs_umode_to_ftype(umode_t mode)
{
return fs_ftype_by_dtype[S_DT(mode)];
}
EXPORT_SYMBOL_GPL(fs_umode_to_ftype);
/**
* fs_umode_to_dtype() - file mode to dirent file type.
* @mode: The file mode to convert.
*
* This function converts the file mode value to the directory
* entry type (DT_*).
*
* Context: Any context.
* Return:
* * DT_UNKNOWN - Unknown type
* * DT_FIFO - FIFO
* * DT_CHR - Character device
* * DT_DIR - Directory
* * DT_BLK - Block device
* * DT_REG - Regular file
* * DT_LNK - Symbolic link
* * DT_SOCK - Local-domain socket
*/
unsigned char fs_umode_to_dtype(umode_t mode)
{
return fs_ftype_to_dtype(fs_umode_to_ftype(mode));
}
EXPORT_SYMBOL_GPL(fs_umode_to_dtype);
| linux-master | fs/fs_types.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/eventfd.c
*
* Copyright (C) 2007 Davide Libenzi <[email protected]>
*
*/
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/sched/signal.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/anon_inodes.h>
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/kref.h>
#include <linux/eventfd.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/idr.h>
#include <linux/uio.h>
static DEFINE_IDA(eventfd_ida);
struct eventfd_ctx {
struct kref kref;
wait_queue_head_t wqh;
/*
* Every time that a write(2) is performed on an eventfd, the
* value of the __u64 being written is added to "count" and a
* wakeup is performed on "wqh". If EFD_SEMAPHORE flag was not
* specified, a read(2) will return the "count" value to userspace,
* and will reset "count" to zero. The kernel side eventfd_signal()
* also, adds to the "count" counter and issue a wakeup.
*/
__u64 count;
unsigned int flags;
int id;
};
__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
{
unsigned long flags;
/*
* Deadlock or stack overflow issues can happen if we recurse here
* through waitqueue wakeup handlers. If the caller users potentially
* nested waitqueues with custom wakeup handlers, then it should
* check eventfd_signal_allowed() before calling this function. If
* it returns false, the eventfd_signal() call should be deferred to a
* safe context.
*/
if (WARN_ON_ONCE(current->in_eventfd))
return 0;
spin_lock_irqsave(&ctx->wqh.lock, flags);
current->in_eventfd = 1;
if (ULLONG_MAX - ctx->count < n)
n = ULLONG_MAX - ctx->count;
ctx->count += n;
if (waitqueue_active(&ctx->wqh))
wake_up_locked_poll(&ctx->wqh, EPOLLIN | mask);
current->in_eventfd = 0;
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
return n;
}
/**
* eventfd_signal - Adds @n to the eventfd counter.
* @ctx: [in] Pointer to the eventfd context.
* @n: [in] Value of the counter to be added to the eventfd internal counter.
* The value cannot be negative.
*
* This function is supposed to be called by the kernel in paths that do not
* allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
* value, and we signal this as overflow condition by returning a EPOLLERR
* to poll(2).
*
* Returns the amount by which the counter was incremented. This will be less
* than @n if the counter has overflowed.
*/
__u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
{
return eventfd_signal_mask(ctx, n, 0);
}
EXPORT_SYMBOL_GPL(eventfd_signal);
static void eventfd_free_ctx(struct eventfd_ctx *ctx)
{
if (ctx->id >= 0)
ida_simple_remove(&eventfd_ida, ctx->id);
kfree(ctx);
}
static void eventfd_free(struct kref *kref)
{
struct eventfd_ctx *ctx = container_of(kref, struct eventfd_ctx, kref);
eventfd_free_ctx(ctx);
}
/**
* eventfd_ctx_put - Releases a reference to the internal eventfd context.
* @ctx: [in] Pointer to eventfd context.
*
* The eventfd context reference must have been previously acquired either
* with eventfd_ctx_fdget() or eventfd_ctx_fileget().
*/
void eventfd_ctx_put(struct eventfd_ctx *ctx)
{
kref_put(&ctx->kref, eventfd_free);
}
EXPORT_SYMBOL_GPL(eventfd_ctx_put);
static int eventfd_release(struct inode *inode, struct file *file)
{
struct eventfd_ctx *ctx = file->private_data;
wake_up_poll(&ctx->wqh, EPOLLHUP);
eventfd_ctx_put(ctx);
return 0;
}
static __poll_t eventfd_poll(struct file *file, poll_table *wait)
{
struct eventfd_ctx *ctx = file->private_data;
__poll_t events = 0;
u64 count;
poll_wait(file, &ctx->wqh, wait);
/*
* All writes to ctx->count occur within ctx->wqh.lock. This read
* can be done outside ctx->wqh.lock because we know that poll_wait
* takes that lock (through add_wait_queue) if our caller will sleep.
*
* The read _can_ therefore seep into add_wait_queue's critical
* section, but cannot move above it! add_wait_queue's spin_lock acts
* as an acquire barrier and ensures that the read be ordered properly
* against the writes. The following CAN happen and is safe:
*
* poll write
* ----------------- ------------
* lock ctx->wqh.lock (in poll_wait)
* count = ctx->count
* __add_wait_queue
* unlock ctx->wqh.lock
* lock ctx->qwh.lock
* ctx->count += n
* if (waitqueue_active)
* wake_up_locked_poll
* unlock ctx->qwh.lock
* eventfd_poll returns 0
*
* but the following, which would miss a wakeup, cannot happen:
*
* poll write
* ----------------- ------------
* count = ctx->count (INVALID!)
* lock ctx->qwh.lock
* ctx->count += n
* **waitqueue_active is false**
* **no wake_up_locked_poll!**
* unlock ctx->qwh.lock
* lock ctx->wqh.lock (in poll_wait)
* __add_wait_queue
* unlock ctx->wqh.lock
* eventfd_poll returns 0
*/
count = READ_ONCE(ctx->count);
if (count > 0)
events |= EPOLLIN;
if (count == ULLONG_MAX)
events |= EPOLLERR;
if (ULLONG_MAX - 1 > count)
events |= EPOLLOUT;
return events;
}
void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
{
lockdep_assert_held(&ctx->wqh.lock);
*cnt = ((ctx->flags & EFD_SEMAPHORE) && ctx->count) ? 1 : ctx->count;
ctx->count -= *cnt;
}
EXPORT_SYMBOL_GPL(eventfd_ctx_do_read);
/**
* eventfd_ctx_remove_wait_queue - Read the current counter and removes wait queue.
* @ctx: [in] Pointer to eventfd context.
* @wait: [in] Wait queue to be removed.
* @cnt: [out] Pointer to the 64-bit counter value.
*
* Returns %0 if successful, or the following error codes:
*
* -EAGAIN : The operation would have blocked.
*
* This is used to atomically remove a wait queue entry from the eventfd wait
* queue head, and read/reset the counter value.
*/
int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
__u64 *cnt)
{
unsigned long flags;
spin_lock_irqsave(&ctx->wqh.lock, flags);
eventfd_ctx_do_read(ctx, cnt);
__remove_wait_queue(&ctx->wqh, wait);
if (*cnt != 0 && waitqueue_active(&ctx->wqh))
wake_up_locked_poll(&ctx->wqh, EPOLLOUT);
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
return *cnt != 0 ? 0 : -EAGAIN;
}
EXPORT_SYMBOL_GPL(eventfd_ctx_remove_wait_queue);
static ssize_t eventfd_read(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct eventfd_ctx *ctx = file->private_data;
__u64 ucnt = 0;
if (iov_iter_count(to) < sizeof(ucnt))
return -EINVAL;
spin_lock_irq(&ctx->wqh.lock);
if (!ctx->count) {
if ((file->f_flags & O_NONBLOCK) ||
(iocb->ki_flags & IOCB_NOWAIT)) {
spin_unlock_irq(&ctx->wqh.lock);
return -EAGAIN;
}
if (wait_event_interruptible_locked_irq(ctx->wqh, ctx->count)) {
spin_unlock_irq(&ctx->wqh.lock);
return -ERESTARTSYS;
}
}
eventfd_ctx_do_read(ctx, &ucnt);
current->in_eventfd = 1;
if (waitqueue_active(&ctx->wqh))
wake_up_locked_poll(&ctx->wqh, EPOLLOUT);
current->in_eventfd = 0;
spin_unlock_irq(&ctx->wqh.lock);
if (unlikely(copy_to_iter(&ucnt, sizeof(ucnt), to) != sizeof(ucnt)))
return -EFAULT;
return sizeof(ucnt);
}
static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t count,
loff_t *ppos)
{
struct eventfd_ctx *ctx = file->private_data;
ssize_t res;
__u64 ucnt;
if (count < sizeof(ucnt))
return -EINVAL;
if (copy_from_user(&ucnt, buf, sizeof(ucnt)))
return -EFAULT;
if (ucnt == ULLONG_MAX)
return -EINVAL;
spin_lock_irq(&ctx->wqh.lock);
res = -EAGAIN;
if (ULLONG_MAX - ctx->count > ucnt)
res = sizeof(ucnt);
else if (!(file->f_flags & O_NONBLOCK)) {
res = wait_event_interruptible_locked_irq(ctx->wqh,
ULLONG_MAX - ctx->count > ucnt);
if (!res)
res = sizeof(ucnt);
}
if (likely(res > 0)) {
ctx->count += ucnt;
current->in_eventfd = 1;
if (waitqueue_active(&ctx->wqh))
wake_up_locked_poll(&ctx->wqh, EPOLLIN);
current->in_eventfd = 0;
}
spin_unlock_irq(&ctx->wqh.lock);
return res;
}
#ifdef CONFIG_PROC_FS
static void eventfd_show_fdinfo(struct seq_file *m, struct file *f)
{
struct eventfd_ctx *ctx = f->private_data;
spin_lock_irq(&ctx->wqh.lock);
seq_printf(m, "eventfd-count: %16llx\n",
(unsigned long long)ctx->count);
spin_unlock_irq(&ctx->wqh.lock);
seq_printf(m, "eventfd-id: %d\n", ctx->id);
seq_printf(m, "eventfd-semaphore: %d\n",
!!(ctx->flags & EFD_SEMAPHORE));
}
#endif
static const struct file_operations eventfd_fops = {
#ifdef CONFIG_PROC_FS
.show_fdinfo = eventfd_show_fdinfo,
#endif
.release = eventfd_release,
.poll = eventfd_poll,
.read_iter = eventfd_read,
.write = eventfd_write,
.llseek = noop_llseek,
};
/**
* eventfd_fget - Acquire a reference of an eventfd file descriptor.
* @fd: [in] Eventfd file descriptor.
*
* Returns a pointer to the eventfd file structure in case of success, or the
* following error pointer:
*
* -EBADF : Invalid @fd file descriptor.
* -EINVAL : The @fd file descriptor is not an eventfd file.
*/
struct file *eventfd_fget(int fd)
{
struct file *file;
file = fget(fd);
if (!file)
return ERR_PTR(-EBADF);
if (file->f_op != &eventfd_fops) {
fput(file);
return ERR_PTR(-EINVAL);
}
return file;
}
EXPORT_SYMBOL_GPL(eventfd_fget);
/**
* eventfd_ctx_fdget - Acquires a reference to the internal eventfd context.
* @fd: [in] Eventfd file descriptor.
*
* Returns a pointer to the internal eventfd context, otherwise the error
* pointers returned by the following functions:
*
* eventfd_fget
*/
struct eventfd_ctx *eventfd_ctx_fdget(int fd)
{
struct eventfd_ctx *ctx;
struct fd f = fdget(fd);
if (!f.file)
return ERR_PTR(-EBADF);
ctx = eventfd_ctx_fileget(f.file);
fdput(f);
return ctx;
}
EXPORT_SYMBOL_GPL(eventfd_ctx_fdget);
/**
* eventfd_ctx_fileget - Acquires a reference to the internal eventfd context.
* @file: [in] Eventfd file pointer.
*
* Returns a pointer to the internal eventfd context, otherwise the error
* pointer:
*
* -EINVAL : The @fd file descriptor is not an eventfd file.
*/
struct eventfd_ctx *eventfd_ctx_fileget(struct file *file)
{
struct eventfd_ctx *ctx;
if (file->f_op != &eventfd_fops)
return ERR_PTR(-EINVAL);
ctx = file->private_data;
kref_get(&ctx->kref);
return ctx;
}
EXPORT_SYMBOL_GPL(eventfd_ctx_fileget);
static int do_eventfd(unsigned int count, int flags)
{
struct eventfd_ctx *ctx;
struct file *file;
int fd;
/* Check the EFD_* constants for consistency. */
BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
if (flags & ~EFD_FLAGS_SET)
return -EINVAL;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
kref_init(&ctx->kref);
init_waitqueue_head(&ctx->wqh);
ctx->count = count;
ctx->flags = flags;
ctx->id = ida_simple_get(&eventfd_ida, 0, 0, GFP_KERNEL);
flags &= EFD_SHARED_FCNTL_FLAGS;
flags |= O_RDWR;
fd = get_unused_fd_flags(flags);
if (fd < 0)
goto err;
file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx, flags);
if (IS_ERR(file)) {
put_unused_fd(fd);
fd = PTR_ERR(file);
goto err;
}
file->f_mode |= FMODE_NOWAIT;
fd_install(fd, file);
return fd;
err:
eventfd_free_ctx(ctx);
return fd;
}
SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
{
return do_eventfd(count, flags);
}
SYSCALL_DEFINE1(eventfd, unsigned int, count)
{
return do_eventfd(count, 0);
}
| linux-master | fs/eventfd.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/export.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/fs.h>
#include <linux/path.h>
#include <linux/slab.h>
#include <linux/fs_struct.h>
#include "internal.h"
/*
* Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
* It can block.
*/
void set_fs_root(struct fs_struct *fs, const struct path *path)
{
struct path old_root;
path_get(path);
spin_lock(&fs->lock);
write_seqcount_begin(&fs->seq);
old_root = fs->root;
fs->root = *path;
write_seqcount_end(&fs->seq);
spin_unlock(&fs->lock);
if (old_root.dentry)
path_put(&old_root);
}
/*
* Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
* It can block.
*/
void set_fs_pwd(struct fs_struct *fs, const struct path *path)
{
struct path old_pwd;
path_get(path);
spin_lock(&fs->lock);
write_seqcount_begin(&fs->seq);
old_pwd = fs->pwd;
fs->pwd = *path;
write_seqcount_end(&fs->seq);
spin_unlock(&fs->lock);
if (old_pwd.dentry)
path_put(&old_pwd);
}
static inline int replace_path(struct path *p, const struct path *old, const struct path *new)
{
if (likely(p->dentry != old->dentry || p->mnt != old->mnt))
return 0;
*p = *new;
return 1;
}
void chroot_fs_refs(const struct path *old_root, const struct path *new_root)
{
struct task_struct *g, *p;
struct fs_struct *fs;
int count = 0;
read_lock(&tasklist_lock);
for_each_process_thread(g, p) {
task_lock(p);
fs = p->fs;
if (fs) {
int hits = 0;
spin_lock(&fs->lock);
write_seqcount_begin(&fs->seq);
hits += replace_path(&fs->root, old_root, new_root);
hits += replace_path(&fs->pwd, old_root, new_root);
write_seqcount_end(&fs->seq);
while (hits--) {
count++;
path_get(new_root);
}
spin_unlock(&fs->lock);
}
task_unlock(p);
}
read_unlock(&tasklist_lock);
while (count--)
path_put(old_root);
}
void free_fs_struct(struct fs_struct *fs)
{
path_put(&fs->root);
path_put(&fs->pwd);
kmem_cache_free(fs_cachep, fs);
}
void exit_fs(struct task_struct *tsk)
{
struct fs_struct *fs = tsk->fs;
if (fs) {
int kill;
task_lock(tsk);
spin_lock(&fs->lock);
tsk->fs = NULL;
kill = !--fs->users;
spin_unlock(&fs->lock);
task_unlock(tsk);
if (kill)
free_fs_struct(fs);
}
}
struct fs_struct *copy_fs_struct(struct fs_struct *old)
{
struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
/* We don't need to lock fs - think why ;-) */
if (fs) {
fs->users = 1;
fs->in_exec = 0;
spin_lock_init(&fs->lock);
seqcount_spinlock_init(&fs->seq, &fs->lock);
fs->umask = old->umask;
spin_lock(&old->lock);
fs->root = old->root;
path_get(&fs->root);
fs->pwd = old->pwd;
path_get(&fs->pwd);
spin_unlock(&old->lock);
}
return fs;
}
int unshare_fs_struct(void)
{
struct fs_struct *fs = current->fs;
struct fs_struct *new_fs = copy_fs_struct(fs);
int kill;
if (!new_fs)
return -ENOMEM;
task_lock(current);
spin_lock(&fs->lock);
kill = !--fs->users;
current->fs = new_fs;
spin_unlock(&fs->lock);
task_unlock(current);
if (kill)
free_fs_struct(fs);
return 0;
}
EXPORT_SYMBOL_GPL(unshare_fs_struct);
int current_umask(void)
{
return current->fs->umask;
}
EXPORT_SYMBOL(current_umask);
/* to be mentioned only in INIT_TASK */
struct fs_struct init_fs = {
.users = 1,
.lock = __SPIN_LOCK_UNLOCKED(init_fs.lock),
.seq = SEQCNT_SPINLOCK_ZERO(init_fs.seq, &init_fs.lock),
.umask = 0022,
};
| linux-master | fs/fs_struct.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/binfmt_script.c
*
* Copyright (C) 1996 Martin von Löwis
* original #!-checking implemented by tytso.
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/binfmts.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/err.h>
#include <linux/fs.h>
static inline bool spacetab(char c) { return c == ' ' || c == '\t'; }
static inline const char *next_non_spacetab(const char *first, const char *last)
{
for (; first <= last; first++)
if (!spacetab(*first))
return first;
return NULL;
}
static inline const char *next_terminator(const char *first, const char *last)
{
for (; first <= last; first++)
if (spacetab(*first) || !*first)
return first;
return NULL;
}
static int load_script(struct linux_binprm *bprm)
{
const char *i_name, *i_sep, *i_arg, *i_end, *buf_end;
struct file *file;
int retval;
/* Not ours to exec if we don't start with "#!". */
if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
return -ENOEXEC;
/*
* This section handles parsing the #! line into separate
* interpreter path and argument strings. We must be careful
* because bprm->buf is not yet guaranteed to be NUL-terminated
* (though the buffer will have trailing NUL padding when the
* file size was smaller than the buffer size).
*
* We do not want to exec a truncated interpreter path, so either
* we find a newline (which indicates nothing is truncated), or
* we find a space/tab/NUL after the interpreter path (which
* itself may be preceded by spaces/tabs). Truncating the
* arguments is fine: the interpreter can re-read the script to
* parse them on its own.
*/
buf_end = bprm->buf + sizeof(bprm->buf) - 1;
i_end = strnchr(bprm->buf, sizeof(bprm->buf), '\n');
if (!i_end) {
i_end = next_non_spacetab(bprm->buf + 2, buf_end);
if (!i_end)
return -ENOEXEC; /* Entire buf is spaces/tabs */
/*
* If there is no later space/tab/NUL we must assume the
* interpreter path is truncated.
*/
if (!next_terminator(i_end, buf_end))
return -ENOEXEC;
i_end = buf_end;
}
/* Trim any trailing spaces/tabs from i_end */
while (spacetab(i_end[-1]))
i_end--;
/* Skip over leading spaces/tabs */
i_name = next_non_spacetab(bprm->buf+2, i_end);
if (!i_name || (i_name == i_end))
return -ENOEXEC; /* No interpreter name found */
/* Is there an optional argument? */
i_arg = NULL;
i_sep = next_terminator(i_name, i_end);
if (i_sep && (*i_sep != '\0'))
i_arg = next_non_spacetab(i_sep, i_end);
/*
* If the script filename will be inaccessible after exec, typically
* because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
* up now (on the assumption that the interpreter will want to load
* this file).
*/
if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
return -ENOENT;
/*
* OK, we've parsed out the interpreter name and
* (optional) argument.
* Splice in (1) the interpreter's name for argv[0]
* (2) (optional) argument to interpreter
* (3) filename of shell script (replace argv[0])
*
* This is done in reverse order, because of how the
* user environment and arguments are stored.
*/
retval = remove_arg_zero(bprm);
if (retval)
return retval;
retval = copy_string_kernel(bprm->interp, bprm);
if (retval < 0)
return retval;
bprm->argc++;
*((char *)i_end) = '\0';
if (i_arg) {
*((char *)i_sep) = '\0';
retval = copy_string_kernel(i_arg, bprm);
if (retval < 0)
return retval;
bprm->argc++;
}
retval = copy_string_kernel(i_name, bprm);
if (retval)
return retval;
bprm->argc++;
retval = bprm_change_interp(i_name, bprm);
if (retval < 0)
return retval;
/*
* OK, now restart the process with the interpreter's dentry.
*/
file = open_exec(i_name);
if (IS_ERR(file))
return PTR_ERR(file);
bprm->interpreter = file;
return 0;
}
static struct linux_binfmt script_format = {
.module = THIS_MODULE,
.load_binary = load_script,
};
static int __init init_script_binfmt(void)
{
register_binfmt(&script_format);
return 0;
}
static void __exit exit_script_binfmt(void)
{
unregister_binfmt(&script_format);
}
core_initcall(init_script_binfmt);
module_exit(exit_script_binfmt);
MODULE_LICENSE("GPL");
| linux-master | fs/binfmt_script.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* Filesystem parameter parser.
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#include <linux/export.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/namei.h>
#include "internal.h"
static const struct constant_table bool_names[] = {
{ "0", false },
{ "1", true },
{ "false", false },
{ "no", false },
{ "true", true },
{ "yes", true },
{ },
};
static const struct constant_table *
__lookup_constant(const struct constant_table *tbl, const char *name)
{
for ( ; tbl->name; tbl++)
if (strcmp(name, tbl->name) == 0)
return tbl;
return NULL;
}
/**
* lookup_constant - Look up a constant by name in an ordered table
* @tbl: The table of constants to search.
* @name: The name to look up.
* @not_found: The value to return if the name is not found.
*/
int lookup_constant(const struct constant_table *tbl, const char *name, int not_found)
{
const struct constant_table *p = __lookup_constant(tbl, name);
return p ? p->value : not_found;
}
EXPORT_SYMBOL(lookup_constant);
static inline bool is_flag(const struct fs_parameter_spec *p)
{
return p->type == NULL;
}
static const struct fs_parameter_spec *fs_lookup_key(
const struct fs_parameter_spec *desc,
struct fs_parameter *param, bool *negated)
{
const struct fs_parameter_spec *p, *other = NULL;
const char *name = param->key;
bool want_flag = param->type == fs_value_is_flag;
*negated = false;
for (p = desc; p->name; p++) {
if (strcmp(p->name, name) != 0)
continue;
if (likely(is_flag(p) == want_flag))
return p;
other = p;
}
if (want_flag) {
if (name[0] == 'n' && name[1] == 'o' && name[2]) {
for (p = desc; p->name; p++) {
if (strcmp(p->name, name + 2) != 0)
continue;
if (!(p->flags & fs_param_neg_with_no))
continue;
*negated = true;
return p;
}
}
}
return other;
}
/*
* fs_parse - Parse a filesystem configuration parameter
* @fc: The filesystem context to log errors through.
* @desc: The parameter description to use.
* @param: The parameter.
* @result: Where to place the result of the parse
*
* Parse a filesystem configuration parameter and attempt a conversion for a
* simple parameter for which this is requested. If successful, the determined
* parameter ID is placed into @result->key, the desired type is indicated in
* @result->t and any converted value is placed into an appropriate member of
* the union in @result.
*
* The function returns the parameter number if the parameter was matched,
* -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that
* unknown parameters are okay and -EINVAL if there was a conversion issue or
* the parameter wasn't recognised and unknowns aren't okay.
*/
int __fs_parse(struct p_log *log,
const struct fs_parameter_spec *desc,
struct fs_parameter *param,
struct fs_parse_result *result)
{
const struct fs_parameter_spec *p;
result->uint_64 = 0;
p = fs_lookup_key(desc, param, &result->negated);
if (!p)
return -ENOPARAM;
if (p->flags & fs_param_deprecated)
warn_plog(log, "Deprecated parameter '%s'", param->key);
/* Try to turn the type we were given into the type desired by the
* parameter and give an error if we can't.
*/
if (is_flag(p)) {
if (param->type != fs_value_is_flag)
return inval_plog(log, "Unexpected value for '%s'",
param->key);
result->boolean = !result->negated;
} else {
int ret = p->type(log, p, param, result);
if (ret)
return ret;
}
return p->opt;
}
EXPORT_SYMBOL(__fs_parse);
/**
* fs_lookup_param - Look up a path referred to by a parameter
* @fc: The filesystem context to log errors through.
* @param: The parameter.
* @want_bdev: T if want a blockdev
* @flags: Pathwalk flags passed to filename_lookup()
* @_path: The result of the lookup
*/
int fs_lookup_param(struct fs_context *fc,
struct fs_parameter *param,
bool want_bdev,
unsigned int flags,
struct path *_path)
{
struct filename *f;
bool put_f;
int ret;
switch (param->type) {
case fs_value_is_string:
f = getname_kernel(param->string);
if (IS_ERR(f))
return PTR_ERR(f);
put_f = true;
break;
case fs_value_is_filename:
f = param->name;
put_f = false;
break;
default:
return invalf(fc, "%s: not usable as path", param->key);
}
ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
if (ret < 0) {
errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
goto out;
}
if (want_bdev &&
!S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) {
path_put(_path);
_path->dentry = NULL;
_path->mnt = NULL;
errorf(fc, "%s: Non-blockdev passed as '%s'",
param->key, f->name);
ret = -ENOTBLK;
}
out:
if (put_f)
putname(f);
return ret;
}
EXPORT_SYMBOL(fs_lookup_param);
static int fs_param_bad_value(struct p_log *log, struct fs_parameter *param)
{
return inval_plog(log, "Bad value for '%s'", param->key);
}
int fs_param_is_bool(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
int b;
if (param->type != fs_value_is_string)
return fs_param_bad_value(log, param);
if (!*param->string && (p->flags & fs_param_can_be_empty))
return 0;
b = lookup_constant(bool_names, param->string, -1);
if (b == -1)
return fs_param_bad_value(log, param);
result->boolean = b;
return 0;
}
EXPORT_SYMBOL(fs_param_is_bool);
int fs_param_is_u32(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
int base = (unsigned long)p->data;
if (param->type != fs_value_is_string)
return fs_param_bad_value(log, param);
if (!*param->string && (p->flags & fs_param_can_be_empty))
return 0;
if (kstrtouint(param->string, base, &result->uint_32) < 0)
return fs_param_bad_value(log, param);
return 0;
}
EXPORT_SYMBOL(fs_param_is_u32);
int fs_param_is_s32(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
if (param->type != fs_value_is_string)
return fs_param_bad_value(log, param);
if (!*param->string && (p->flags & fs_param_can_be_empty))
return 0;
if (kstrtoint(param->string, 0, &result->int_32) < 0)
return fs_param_bad_value(log, param);
return 0;
}
EXPORT_SYMBOL(fs_param_is_s32);
int fs_param_is_u64(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
if (param->type != fs_value_is_string)
return fs_param_bad_value(log, param);
if (!*param->string && (p->flags & fs_param_can_be_empty))
return 0;
if (kstrtoull(param->string, 0, &result->uint_64) < 0)
return fs_param_bad_value(log, param);
return 0;
}
EXPORT_SYMBOL(fs_param_is_u64);
int fs_param_is_enum(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
const struct constant_table *c;
if (param->type != fs_value_is_string)
return fs_param_bad_value(log, param);
if (!*param->string && (p->flags & fs_param_can_be_empty))
return 0;
c = __lookup_constant(p->data, param->string);
if (!c)
return fs_param_bad_value(log, param);
result->uint_32 = c->value;
return 0;
}
EXPORT_SYMBOL(fs_param_is_enum);
int fs_param_is_string(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
if (param->type != fs_value_is_string ||
(!*param->string && !(p->flags & fs_param_can_be_empty)))
return fs_param_bad_value(log, param);
return 0;
}
EXPORT_SYMBOL(fs_param_is_string);
int fs_param_is_blob(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
if (param->type != fs_value_is_blob)
return fs_param_bad_value(log, param);
return 0;
}
EXPORT_SYMBOL(fs_param_is_blob);
int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
switch (param->type) {
case fs_value_is_string:
if ((!*param->string && !(p->flags & fs_param_can_be_empty)) ||
kstrtouint(param->string, 0, &result->uint_32) < 0)
break;
if (result->uint_32 <= INT_MAX)
return 0;
break;
case fs_value_is_file:
result->uint_32 = param->dirfd;
if (result->uint_32 <= INT_MAX)
return 0;
break;
default:
break;
}
return fs_param_bad_value(log, param);
}
EXPORT_SYMBOL(fs_param_is_fd);
int fs_param_is_blockdev(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
return 0;
}
EXPORT_SYMBOL(fs_param_is_blockdev);
int fs_param_is_path(struct p_log *log, const struct fs_parameter_spec *p,
struct fs_parameter *param, struct fs_parse_result *result)
{
return 0;
}
EXPORT_SYMBOL(fs_param_is_path);
#ifdef CONFIG_VALIDATE_FS_PARSER
/**
* validate_constant_table - Validate a constant table
* @tbl: The constant table to validate.
* @tbl_size: The size of the table.
* @low: The lowest permissible value.
* @high: The highest permissible value.
* @special: One special permissible value outside of the range.
*/
bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
int low, int high, int special)
{
size_t i;
bool good = true;
if (tbl_size == 0) {
pr_warn("VALIDATE C-TBL: Empty\n");
return true;
}
for (i = 0; i < tbl_size; i++) {
if (!tbl[i].name) {
pr_err("VALIDATE C-TBL[%zu]: Null\n", i);
good = false;
} else if (i > 0 && tbl[i - 1].name) {
int c = strcmp(tbl[i-1].name, tbl[i].name);
if (c == 0) {
pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n",
i, tbl[i].name);
good = false;
}
if (c > 0) {
pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n",
i, tbl[i-1].name, tbl[i].name);
good = false;
}
}
if (tbl[i].value != special &&
(tbl[i].value < low || tbl[i].value > high)) {
pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n",
i, tbl[i].name, tbl[i].value, low, high);
good = false;
}
}
return good;
}
/**
* fs_validate_description - Validate a parameter description
* @name: The parameter name to search for.
* @desc: The parameter description to validate.
*/
bool fs_validate_description(const char *name,
const struct fs_parameter_spec *desc)
{
const struct fs_parameter_spec *param, *p2;
bool good = true;
for (param = desc; param->name; param++) {
/* Check for duplicate parameter names */
for (p2 = desc; p2 < param; p2++) {
if (strcmp(param->name, p2->name) == 0) {
if (is_flag(param) != is_flag(p2))
continue;
pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n",
name, param->name);
good = false;
}
}
}
return good;
}
#endif /* CONFIG_VALIDATE_FS_PARSER */
| linux-master | fs/fs_parser.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/dax.c - Direct Access filesystem code
* Copyright (c) 2013-2014 Intel Corporation
* Author: Matthew Wilcox <[email protected]>
* Author: Ross Zwisler <[email protected]>
*/
#include <linux/atomic.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/dax.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/memcontrol.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/pagevec.h>
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/uio.h>
#include <linux/vmstat.h>
#include <linux/pfn_t.h>
#include <linux/sizes.h>
#include <linux/mmu_notifier.h>
#include <linux/iomap.h>
#include <linux/rmap.h>
#include <asm/pgalloc.h>
#define CREATE_TRACE_POINTS
#include <trace/events/fs_dax.h>
/* We choose 4096 entries - same as per-zone page wait tables */
#define DAX_WAIT_TABLE_BITS 12
#define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS)
/* The 'colour' (ie low bits) within a PMD of a page offset. */
#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
#define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT)
static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES];
static int __init init_dax_wait_table(void)
{
int i;
for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++)
init_waitqueue_head(wait_table + i);
return 0;
}
fs_initcall(init_dax_wait_table);
/*
* DAX pagecache entries use XArray value entries so they can't be mistaken
* for pages. We use one bit for locking, one bit for the entry size (PMD)
* and two more to tell us if the entry is a zero page or an empty entry that
* is just used for locking. In total four special bits.
*
* If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE
* and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem
* block allocation.
*/
#define DAX_SHIFT (4)
#define DAX_LOCKED (1UL << 0)
#define DAX_PMD (1UL << 1)
#define DAX_ZERO_PAGE (1UL << 2)
#define DAX_EMPTY (1UL << 3)
static unsigned long dax_to_pfn(void *entry)
{
return xa_to_value(entry) >> DAX_SHIFT;
}
static void *dax_make_entry(pfn_t pfn, unsigned long flags)
{
return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT));
}
static bool dax_is_locked(void *entry)
{
return xa_to_value(entry) & DAX_LOCKED;
}
static unsigned int dax_entry_order(void *entry)
{
if (xa_to_value(entry) & DAX_PMD)
return PMD_ORDER;
return 0;
}
static unsigned long dax_is_pmd_entry(void *entry)
{
return xa_to_value(entry) & DAX_PMD;
}
static bool dax_is_pte_entry(void *entry)
{
return !(xa_to_value(entry) & DAX_PMD);
}
static int dax_is_zero_entry(void *entry)
{
return xa_to_value(entry) & DAX_ZERO_PAGE;
}
static int dax_is_empty_entry(void *entry)
{
return xa_to_value(entry) & DAX_EMPTY;
}
/*
* true if the entry that was found is of a smaller order than the entry
* we were looking for
*/
static bool dax_is_conflict(void *entry)
{
return entry == XA_RETRY_ENTRY;
}
/*
* DAX page cache entry locking
*/
struct exceptional_entry_key {
struct xarray *xa;
pgoff_t entry_start;
};
struct wait_exceptional_entry_queue {
wait_queue_entry_t wait;
struct exceptional_entry_key key;
};
/**
* enum dax_wake_mode: waitqueue wakeup behaviour
* @WAKE_ALL: wake all waiters in the waitqueue
* @WAKE_NEXT: wake only the first waiter in the waitqueue
*/
enum dax_wake_mode {
WAKE_ALL,
WAKE_NEXT,
};
static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas,
void *entry, struct exceptional_entry_key *key)
{
unsigned long hash;
unsigned long index = xas->xa_index;
/*
* If 'entry' is a PMD, align the 'index' that we use for the wait
* queue to the start of that PMD. This ensures that all offsets in
* the range covered by the PMD map to the same bit lock.
*/
if (dax_is_pmd_entry(entry))
index &= ~PG_PMD_COLOUR;
key->xa = xas->xa;
key->entry_start = index;
hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS);
return wait_table + hash;
}
static int wake_exceptional_entry_func(wait_queue_entry_t *wait,
unsigned int mode, int sync, void *keyp)
{
struct exceptional_entry_key *key = keyp;
struct wait_exceptional_entry_queue *ewait =
container_of(wait, struct wait_exceptional_entry_queue, wait);
if (key->xa != ewait->key.xa ||
key->entry_start != ewait->key.entry_start)
return 0;
return autoremove_wake_function(wait, mode, sync, NULL);
}
/*
* @entry may no longer be the entry at the index in the mapping.
* The important information it's conveying is whether the entry at
* this index used to be a PMD entry.
*/
static void dax_wake_entry(struct xa_state *xas, void *entry,
enum dax_wake_mode mode)
{
struct exceptional_entry_key key;
wait_queue_head_t *wq;
wq = dax_entry_waitqueue(xas, entry, &key);
/*
* Checking for locked entry and prepare_to_wait_exclusive() happens
* under the i_pages lock, ditto for entry handling in our callers.
* So at this point all tasks that could have seen our entry locked
* must be in the waitqueue and the following check will see them.
*/
if (waitqueue_active(wq))
__wake_up(wq, TASK_NORMAL, mode == WAKE_ALL ? 0 : 1, &key);
}
/*
* Look up entry in page cache, wait for it to become unlocked if it
* is a DAX entry and return it. The caller must subsequently call
* put_unlocked_entry() if it did not lock the entry or dax_unlock_entry()
* if it did. The entry returned may have a larger order than @order.
* If @order is larger than the order of the entry found in i_pages, this
* function returns a dax_is_conflict entry.
*
* Must be called with the i_pages lock held.
*/
static void *get_unlocked_entry(struct xa_state *xas, unsigned int order)
{
void *entry;
struct wait_exceptional_entry_queue ewait;
wait_queue_head_t *wq;
init_wait(&ewait.wait);
ewait.wait.func = wake_exceptional_entry_func;
for (;;) {
entry = xas_find_conflict(xas);
if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
return entry;
if (dax_entry_order(entry) < order)
return XA_RETRY_ENTRY;
if (!dax_is_locked(entry))
return entry;
wq = dax_entry_waitqueue(xas, entry, &ewait.key);
prepare_to_wait_exclusive(wq, &ewait.wait,
TASK_UNINTERRUPTIBLE);
xas_unlock_irq(xas);
xas_reset(xas);
schedule();
finish_wait(wq, &ewait.wait);
xas_lock_irq(xas);
}
}
/*
* The only thing keeping the address space around is the i_pages lock
* (it's cycled in clear_inode() after removing the entries from i_pages)
* After we call xas_unlock_irq(), we cannot touch xas->xa.
*/
static void wait_entry_unlocked(struct xa_state *xas, void *entry)
{
struct wait_exceptional_entry_queue ewait;
wait_queue_head_t *wq;
init_wait(&ewait.wait);
ewait.wait.func = wake_exceptional_entry_func;
wq = dax_entry_waitqueue(xas, entry, &ewait.key);
/*
* Unlike get_unlocked_entry() there is no guarantee that this
* path ever successfully retrieves an unlocked entry before an
* inode dies. Perform a non-exclusive wait in case this path
* never successfully performs its own wake up.
*/
prepare_to_wait(wq, &ewait.wait, TASK_UNINTERRUPTIBLE);
xas_unlock_irq(xas);
schedule();
finish_wait(wq, &ewait.wait);
}
static void put_unlocked_entry(struct xa_state *xas, void *entry,
enum dax_wake_mode mode)
{
if (entry && !dax_is_conflict(entry))
dax_wake_entry(xas, entry, mode);
}
/*
* We used the xa_state to get the entry, but then we locked the entry and
* dropped the xa_lock, so we know the xa_state is stale and must be reset
* before use.
*/
static void dax_unlock_entry(struct xa_state *xas, void *entry)
{
void *old;
BUG_ON(dax_is_locked(entry));
xas_reset(xas);
xas_lock_irq(xas);
old = xas_store(xas, entry);
xas_unlock_irq(xas);
BUG_ON(!dax_is_locked(old));
dax_wake_entry(xas, entry, WAKE_NEXT);
}
/*
* Return: The entry stored at this location before it was locked.
*/
static void *dax_lock_entry(struct xa_state *xas, void *entry)
{
unsigned long v = xa_to_value(entry);
return xas_store(xas, xa_mk_value(v | DAX_LOCKED));
}
static unsigned long dax_entry_size(void *entry)
{
if (dax_is_zero_entry(entry))
return 0;
else if (dax_is_empty_entry(entry))
return 0;
else if (dax_is_pmd_entry(entry))
return PMD_SIZE;
else
return PAGE_SIZE;
}
static unsigned long dax_end_pfn(void *entry)
{
return dax_to_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE;
}
/*
* Iterate through all mapped pfns represented by an entry, i.e. skip
* 'empty' and 'zero' entries.
*/
#define for_each_mapped_pfn(entry, pfn) \
for (pfn = dax_to_pfn(entry); \
pfn < dax_end_pfn(entry); pfn++)
static inline bool dax_page_is_shared(struct page *page)
{
return page->mapping == PAGE_MAPPING_DAX_SHARED;
}
/*
* Set the page->mapping with PAGE_MAPPING_DAX_SHARED flag, increase the
* refcount.
*/
static inline void dax_page_share_get(struct page *page)
{
if (page->mapping != PAGE_MAPPING_DAX_SHARED) {
/*
* Reset the index if the page was already mapped
* regularly before.
*/
if (page->mapping)
page->share = 1;
page->mapping = PAGE_MAPPING_DAX_SHARED;
}
page->share++;
}
static inline unsigned long dax_page_share_put(struct page *page)
{
return --page->share;
}
/*
* When it is called in dax_insert_entry(), the shared flag will indicate that
* whether this entry is shared by multiple files. If so, set the page->mapping
* PAGE_MAPPING_DAX_SHARED, and use page->share as refcount.
*/
static void dax_associate_entry(void *entry, struct address_space *mapping,
struct vm_area_struct *vma, unsigned long address, bool shared)
{
unsigned long size = dax_entry_size(entry), pfn, index;
int i = 0;
if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
return;
index = linear_page_index(vma, address & ~(size - 1));
for_each_mapped_pfn(entry, pfn) {
struct page *page = pfn_to_page(pfn);
if (shared) {
dax_page_share_get(page);
} else {
WARN_ON_ONCE(page->mapping);
page->mapping = mapping;
page->index = index + i++;
}
}
}
static void dax_disassociate_entry(void *entry, struct address_space *mapping,
bool trunc)
{
unsigned long pfn;
if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
return;
for_each_mapped_pfn(entry, pfn) {
struct page *page = pfn_to_page(pfn);
WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
if (dax_page_is_shared(page)) {
/* keep the shared flag if this page is still shared */
if (dax_page_share_put(page) > 0)
continue;
} else
WARN_ON_ONCE(page->mapping && page->mapping != mapping);
page->mapping = NULL;
page->index = 0;
}
}
static struct page *dax_busy_page(void *entry)
{
unsigned long pfn;
for_each_mapped_pfn(entry, pfn) {
struct page *page = pfn_to_page(pfn);
if (page_ref_count(page) > 1)
return page;
}
return NULL;
}
/*
* dax_lock_page - Lock the DAX entry corresponding to a page
* @page: The page whose entry we want to lock
*
* Context: Process context.
* Return: A cookie to pass to dax_unlock_page() or 0 if the entry could
* not be locked.
*/
dax_entry_t dax_lock_page(struct page *page)
{
XA_STATE(xas, NULL, 0);
void *entry;
/* Ensure page->mapping isn't freed while we look at it */
rcu_read_lock();
for (;;) {
struct address_space *mapping = READ_ONCE(page->mapping);
entry = NULL;
if (!mapping || !dax_mapping(mapping))
break;
/*
* In the device-dax case there's no need to lock, a
* struct dev_pagemap pin is sufficient to keep the
* inode alive, and we assume we have dev_pagemap pin
* otherwise we would not have a valid pfn_to_page()
* translation.
*/
entry = (void *)~0UL;
if (S_ISCHR(mapping->host->i_mode))
break;
xas.xa = &mapping->i_pages;
xas_lock_irq(&xas);
if (mapping != page->mapping) {
xas_unlock_irq(&xas);
continue;
}
xas_set(&xas, page->index);
entry = xas_load(&xas);
if (dax_is_locked(entry)) {
rcu_read_unlock();
wait_entry_unlocked(&xas, entry);
rcu_read_lock();
continue;
}
dax_lock_entry(&xas, entry);
xas_unlock_irq(&xas);
break;
}
rcu_read_unlock();
return (dax_entry_t)entry;
}
void dax_unlock_page(struct page *page, dax_entry_t cookie)
{
struct address_space *mapping = page->mapping;
XA_STATE(xas, &mapping->i_pages, page->index);
if (S_ISCHR(mapping->host->i_mode))
return;
dax_unlock_entry(&xas, (void *)cookie);
}
/*
* dax_lock_mapping_entry - Lock the DAX entry corresponding to a mapping
* @mapping: the file's mapping whose entry we want to lock
* @index: the offset within this file
* @page: output the dax page corresponding to this dax entry
*
* Return: A cookie to pass to dax_unlock_mapping_entry() or 0 if the entry
* could not be locked.
*/
dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, pgoff_t index,
struct page **page)
{
XA_STATE(xas, NULL, 0);
void *entry;
rcu_read_lock();
for (;;) {
entry = NULL;
if (!dax_mapping(mapping))
break;
xas.xa = &mapping->i_pages;
xas_lock_irq(&xas);
xas_set(&xas, index);
entry = xas_load(&xas);
if (dax_is_locked(entry)) {
rcu_read_unlock();
wait_entry_unlocked(&xas, entry);
rcu_read_lock();
continue;
}
if (!entry ||
dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
/*
* Because we are looking for entry from file's mapping
* and index, so the entry may not be inserted for now,
* or even a zero/empty entry. We don't think this is
* an error case. So, return a special value and do
* not output @page.
*/
entry = (void *)~0UL;
} else {
*page = pfn_to_page(dax_to_pfn(entry));
dax_lock_entry(&xas, entry);
}
xas_unlock_irq(&xas);
break;
}
rcu_read_unlock();
return (dax_entry_t)entry;
}
void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index,
dax_entry_t cookie)
{
XA_STATE(xas, &mapping->i_pages, index);
if (cookie == ~0UL)
return;
dax_unlock_entry(&xas, (void *)cookie);
}
/*
* Find page cache entry at given index. If it is a DAX entry, return it
* with the entry locked. If the page cache doesn't contain an entry at
* that index, add a locked empty entry.
*
* When requesting an entry with size DAX_PMD, grab_mapping_entry() will
* either return that locked entry or will return VM_FAULT_FALLBACK.
* This will happen if there are any PTE entries within the PMD range
* that we are requesting.
*
* We always favor PTE entries over PMD entries. There isn't a flow where we
* evict PTE entries in order to 'upgrade' them to a PMD entry. A PMD
* insertion will fail if it finds any PTE entries already in the tree, and a
* PTE insertion will cause an existing PMD entry to be unmapped and
* downgraded to PTE entries. This happens for both PMD zero pages as
* well as PMD empty entries.
*
* The exception to this downgrade path is for PMD entries that have
* real storage backing them. We will leave these real PMD entries in
* the tree, and PTE writes will simply dirty the entire PMD entry.
*
* Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For
* persistent memory the benefit is doubtful. We can add that later if we can
* show it helps.
*
* On error, this function does not return an ERR_PTR. Instead it returns
* a VM_FAULT code, encoded as an xarray internal entry. The ERR_PTR values
* overlap with xarray value entries.
*/
static void *grab_mapping_entry(struct xa_state *xas,
struct address_space *mapping, unsigned int order)
{
unsigned long index = xas->xa_index;
bool pmd_downgrade; /* splitting PMD entry into PTE entries? */
void *entry;
retry:
pmd_downgrade = false;
xas_lock_irq(xas);
entry = get_unlocked_entry(xas, order);
if (entry) {
if (dax_is_conflict(entry))
goto fallback;
if (!xa_is_value(entry)) {
xas_set_err(xas, -EIO);
goto out_unlock;
}
if (order == 0) {
if (dax_is_pmd_entry(entry) &&
(dax_is_zero_entry(entry) ||
dax_is_empty_entry(entry))) {
pmd_downgrade = true;
}
}
}
if (pmd_downgrade) {
/*
* Make sure 'entry' remains valid while we drop
* the i_pages lock.
*/
dax_lock_entry(xas, entry);
/*
* Besides huge zero pages the only other thing that gets
* downgraded are empty entries which don't need to be
* unmapped.
*/
if (dax_is_zero_entry(entry)) {
xas_unlock_irq(xas);
unmap_mapping_pages(mapping,
xas->xa_index & ~PG_PMD_COLOUR,
PG_PMD_NR, false);
xas_reset(xas);
xas_lock_irq(xas);
}
dax_disassociate_entry(entry, mapping, false);
xas_store(xas, NULL); /* undo the PMD join */
dax_wake_entry(xas, entry, WAKE_ALL);
mapping->nrpages -= PG_PMD_NR;
entry = NULL;
xas_set(xas, index);
}
if (entry) {
dax_lock_entry(xas, entry);
} else {
unsigned long flags = DAX_EMPTY;
if (order > 0)
flags |= DAX_PMD;
entry = dax_make_entry(pfn_to_pfn_t(0), flags);
dax_lock_entry(xas, entry);
if (xas_error(xas))
goto out_unlock;
mapping->nrpages += 1UL << order;
}
out_unlock:
xas_unlock_irq(xas);
if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM))
goto retry;
if (xas->xa_node == XA_ERROR(-ENOMEM))
return xa_mk_internal(VM_FAULT_OOM);
if (xas_error(xas))
return xa_mk_internal(VM_FAULT_SIGBUS);
return entry;
fallback:
xas_unlock_irq(xas);
return xa_mk_internal(VM_FAULT_FALLBACK);
}
/**
* dax_layout_busy_page_range - find first pinned page in @mapping
* @mapping: address space to scan for a page with ref count > 1
* @start: Starting offset. Page containing 'start' is included.
* @end: End offset. Page containing 'end' is included. If 'end' is LLONG_MAX,
* pages from 'start' till the end of file are included.
*
* DAX requires ZONE_DEVICE mapped pages. These pages are never
* 'onlined' to the page allocator so they are considered idle when
* page->count == 1. A filesystem uses this interface to determine if
* any page in the mapping is busy, i.e. for DMA, or other
* get_user_pages() usages.
*
* It is expected that the filesystem is holding locks to block the
* establishment of new mappings in this address_space. I.e. it expects
* to be able to run unmap_mapping_range() and subsequently not race
* mapping_mapped() becoming true.
*/
struct page *dax_layout_busy_page_range(struct address_space *mapping,
loff_t start, loff_t end)
{
void *entry;
unsigned int scanned = 0;
struct page *page = NULL;
pgoff_t start_idx = start >> PAGE_SHIFT;
pgoff_t end_idx;
XA_STATE(xas, &mapping->i_pages, start_idx);
/*
* In the 'limited' case get_user_pages() for dax is disabled.
*/
if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
return NULL;
if (!dax_mapping(mapping) || !mapping_mapped(mapping))
return NULL;
/* If end == LLONG_MAX, all pages from start to till end of file */
if (end == LLONG_MAX)
end_idx = ULONG_MAX;
else
end_idx = end >> PAGE_SHIFT;
/*
* If we race get_user_pages_fast() here either we'll see the
* elevated page count in the iteration and wait, or
* get_user_pages_fast() will see that the page it took a reference
* against is no longer mapped in the page tables and bail to the
* get_user_pages() slow path. The slow path is protected by
* pte_lock() and pmd_lock(). New references are not taken without
* holding those locks, and unmap_mapping_pages() will not zero the
* pte or pmd without holding the respective lock, so we are
* guaranteed to either see new references or prevent new
* references from being established.
*/
unmap_mapping_pages(mapping, start_idx, end_idx - start_idx + 1, 0);
xas_lock_irq(&xas);
xas_for_each(&xas, entry, end_idx) {
if (WARN_ON_ONCE(!xa_is_value(entry)))
continue;
if (unlikely(dax_is_locked(entry)))
entry = get_unlocked_entry(&xas, 0);
if (entry)
page = dax_busy_page(entry);
put_unlocked_entry(&xas, entry, WAKE_NEXT);
if (page)
break;
if (++scanned % XA_CHECK_SCHED)
continue;
xas_pause(&xas);
xas_unlock_irq(&xas);
cond_resched();
xas_lock_irq(&xas);
}
xas_unlock_irq(&xas);
return page;
}
EXPORT_SYMBOL_GPL(dax_layout_busy_page_range);
struct page *dax_layout_busy_page(struct address_space *mapping)
{
return dax_layout_busy_page_range(mapping, 0, LLONG_MAX);
}
EXPORT_SYMBOL_GPL(dax_layout_busy_page);
static int __dax_invalidate_entry(struct address_space *mapping,
pgoff_t index, bool trunc)
{
XA_STATE(xas, &mapping->i_pages, index);
int ret = 0;
void *entry;
xas_lock_irq(&xas);
entry = get_unlocked_entry(&xas, 0);
if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
goto out;
if (!trunc &&
(xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) ||
xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE)))
goto out;
dax_disassociate_entry(entry, mapping, trunc);
xas_store(&xas, NULL);
mapping->nrpages -= 1UL << dax_entry_order(entry);
ret = 1;
out:
put_unlocked_entry(&xas, entry, WAKE_ALL);
xas_unlock_irq(&xas);
return ret;
}
static int __dax_clear_dirty_range(struct address_space *mapping,
pgoff_t start, pgoff_t end)
{
XA_STATE(xas, &mapping->i_pages, start);
unsigned int scanned = 0;
void *entry;
xas_lock_irq(&xas);
xas_for_each(&xas, entry, end) {
entry = get_unlocked_entry(&xas, 0);
xas_clear_mark(&xas, PAGECACHE_TAG_DIRTY);
xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE);
put_unlocked_entry(&xas, entry, WAKE_NEXT);
if (++scanned % XA_CHECK_SCHED)
continue;
xas_pause(&xas);
xas_unlock_irq(&xas);
cond_resched();
xas_lock_irq(&xas);
}
xas_unlock_irq(&xas);
return 0;
}
/*
* Delete DAX entry at @index from @mapping. Wait for it
* to be unlocked before deleting it.
*/
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
{
int ret = __dax_invalidate_entry(mapping, index, true);
/*
* This gets called from truncate / punch_hole path. As such, the caller
* must hold locks protecting against concurrent modifications of the
* page cache (usually fs-private i_mmap_sem for writing). Since the
* caller has seen a DAX entry for this index, we better find it
* at that index as well...
*/
WARN_ON_ONCE(!ret);
return ret;
}
/*
* Invalidate DAX entry if it is clean.
*/
int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
pgoff_t index)
{
return __dax_invalidate_entry(mapping, index, false);
}
static pgoff_t dax_iomap_pgoff(const struct iomap *iomap, loff_t pos)
{
return PHYS_PFN(iomap->addr + (pos & PAGE_MASK) - iomap->offset);
}
static int copy_cow_page_dax(struct vm_fault *vmf, const struct iomap_iter *iter)
{
pgoff_t pgoff = dax_iomap_pgoff(&iter->iomap, iter->pos);
void *vto, *kaddr;
long rc;
int id;
id = dax_read_lock();
rc = dax_direct_access(iter->iomap.dax_dev, pgoff, 1, DAX_ACCESS,
&kaddr, NULL);
if (rc < 0) {
dax_read_unlock(id);
return rc;
}
vto = kmap_atomic(vmf->cow_page);
copy_user_page(vto, kaddr, vmf->address, vmf->cow_page);
kunmap_atomic(vto);
dax_read_unlock(id);
return 0;
}
/*
* MAP_SYNC on a dax mapping guarantees dirty metadata is
* flushed on write-faults (non-cow), but not read-faults.
*/
static bool dax_fault_is_synchronous(const struct iomap_iter *iter,
struct vm_area_struct *vma)
{
return (iter->flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) &&
(iter->iomap.flags & IOMAP_F_DIRTY);
}
/*
* By this point grab_mapping_entry() has ensured that we have a locked entry
* of the appropriate size so we don't have to worry about downgrading PMDs to
* PTEs. If we happen to be trying to insert a PTE and there is a PMD
* already in the tree, we will skip the insertion and just dirty the PMD as
* appropriate.
*/
static void *dax_insert_entry(struct xa_state *xas, struct vm_fault *vmf,
const struct iomap_iter *iter, void *entry, pfn_t pfn,
unsigned long flags)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
void *new_entry = dax_make_entry(pfn, flags);
bool write = iter->flags & IOMAP_WRITE;
bool dirty = write && !dax_fault_is_synchronous(iter, vmf->vma);
bool shared = iter->iomap.flags & IOMAP_F_SHARED;
if (dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
if (shared || (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE))) {
unsigned long index = xas->xa_index;
/* we are replacing a zero page with block mapping */
if (dax_is_pmd_entry(entry))
unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
PG_PMD_NR, false);
else /* pte entry */
unmap_mapping_pages(mapping, index, 1, false);
}
xas_reset(xas);
xas_lock_irq(xas);
if (shared || dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
void *old;
dax_disassociate_entry(entry, mapping, false);
dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address,
shared);
/*
* Only swap our new entry into the page cache if the current
* entry is a zero page or an empty entry. If a normal PTE or
* PMD entry is already in the cache, we leave it alone. This
* means that if we are trying to insert a PTE and the
* existing entry is a PMD, we will just leave the PMD in the
* tree and dirty it if necessary.
*/
old = dax_lock_entry(xas, new_entry);
WARN_ON_ONCE(old != xa_mk_value(xa_to_value(entry) |
DAX_LOCKED));
entry = new_entry;
} else {
xas_load(xas); /* Walk the xa_state */
}
if (dirty)
xas_set_mark(xas, PAGECACHE_TAG_DIRTY);
if (write && shared)
xas_set_mark(xas, PAGECACHE_TAG_TOWRITE);
xas_unlock_irq(xas);
return entry;
}
static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
struct address_space *mapping, void *entry)
{
unsigned long pfn, index, count, end;
long ret = 0;
struct vm_area_struct *vma;
/*
* A page got tagged dirty in DAX mapping? Something is seriously
* wrong.
*/
if (WARN_ON(!xa_is_value(entry)))
return -EIO;
if (unlikely(dax_is_locked(entry))) {
void *old_entry = entry;
entry = get_unlocked_entry(xas, 0);
/* Entry got punched out / reallocated? */
if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
goto put_unlocked;
/*
* Entry got reallocated elsewhere? No need to writeback.
* We have to compare pfns as we must not bail out due to
* difference in lockbit or entry type.
*/
if (dax_to_pfn(old_entry) != dax_to_pfn(entry))
goto put_unlocked;
if (WARN_ON_ONCE(dax_is_empty_entry(entry) ||
dax_is_zero_entry(entry))) {
ret = -EIO;
goto put_unlocked;
}
/* Another fsync thread may have already done this entry */
if (!xas_get_mark(xas, PAGECACHE_TAG_TOWRITE))
goto put_unlocked;
}
/* Lock the entry to serialize with page faults */
dax_lock_entry(xas, entry);
/*
* We can clear the tag now but we have to be careful so that concurrent
* dax_writeback_one() calls for the same index cannot finish before we
* actually flush the caches. This is achieved as the calls will look
* at the entry only under the i_pages lock and once they do that
* they will see the entry locked and wait for it to unlock.
*/
xas_clear_mark(xas, PAGECACHE_TAG_TOWRITE);
xas_unlock_irq(xas);
/*
* If dax_writeback_mapping_range() was given a wbc->range_start
* in the middle of a PMD, the 'index' we use needs to be
* aligned to the start of the PMD.
* This allows us to flush for PMD_SIZE and not have to worry about
* partial PMD writebacks.
*/
pfn = dax_to_pfn(entry);
count = 1UL << dax_entry_order(entry);
index = xas->xa_index & ~(count - 1);
end = index + count - 1;
/* Walk all mappings of a given index of a file and writeprotect them */
i_mmap_lock_read(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, index, end) {
pfn_mkclean_range(pfn, count, index, vma);
cond_resched();
}
i_mmap_unlock_read(mapping);
dax_flush(dax_dev, page_address(pfn_to_page(pfn)), count * PAGE_SIZE);
/*
* After we have flushed the cache, we can clear the dirty tag. There
* cannot be new dirty data in the pfn after the flush has completed as
* the pfn mappings are writeprotected and fault waits for mapping
* entry lock.
*/
xas_reset(xas);
xas_lock_irq(xas);
xas_store(xas, entry);
xas_clear_mark(xas, PAGECACHE_TAG_DIRTY);
dax_wake_entry(xas, entry, WAKE_NEXT);
trace_dax_writeback_one(mapping->host, index, count);
return ret;
put_unlocked:
put_unlocked_entry(xas, entry, WAKE_NEXT);
return ret;
}
/*
* Flush the mapping to the persistent domain within the byte range of [start,
* end]. This is required by data integrity operations to ensure file data is
* on persistent storage prior to completion of the operation.
*/
int dax_writeback_mapping_range(struct address_space *mapping,
struct dax_device *dax_dev, struct writeback_control *wbc)
{
XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT);
struct inode *inode = mapping->host;
pgoff_t end_index = wbc->range_end >> PAGE_SHIFT;
void *entry;
int ret = 0;
unsigned int scanned = 0;
if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))
return -EIO;
if (mapping_empty(mapping) || wbc->sync_mode != WB_SYNC_ALL)
return 0;
trace_dax_writeback_range(inode, xas.xa_index, end_index);
tag_pages_for_writeback(mapping, xas.xa_index, end_index);
xas_lock_irq(&xas);
xas_for_each_marked(&xas, entry, end_index, PAGECACHE_TAG_TOWRITE) {
ret = dax_writeback_one(&xas, dax_dev, mapping, entry);
if (ret < 0) {
mapping_set_error(mapping, ret);
break;
}
if (++scanned % XA_CHECK_SCHED)
continue;
xas_pause(&xas);
xas_unlock_irq(&xas);
cond_resched();
xas_lock_irq(&xas);
}
xas_unlock_irq(&xas);
trace_dax_writeback_range_done(inode, xas.xa_index, end_index);
return ret;
}
EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos,
size_t size, void **kaddr, pfn_t *pfnp)
{
pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
int id, rc = 0;
long length;
id = dax_read_lock();
length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size),
DAX_ACCESS, kaddr, pfnp);
if (length < 0) {
rc = length;
goto out;
}
if (!pfnp)
goto out_check_addr;
rc = -EINVAL;
if (PFN_PHYS(length) < size)
goto out;
if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1))
goto out;
/* For larger pages we need devmap */
if (length > 1 && !pfn_t_devmap(*pfnp))
goto out;
rc = 0;
out_check_addr:
if (!kaddr)
goto out;
if (!*kaddr)
rc = -EFAULT;
out:
dax_read_unlock(id);
return rc;
}
/**
* dax_iomap_copy_around - Prepare for an unaligned write to a shared/cow page
* by copying the data before and after the range to be written.
* @pos: address to do copy from.
* @length: size of copy operation.
* @align_size: aligned w.r.t align_size (either PMD_SIZE or PAGE_SIZE)
* @srcmap: iomap srcmap
* @daddr: destination address to copy to.
*
* This can be called from two places. Either during DAX write fault (page
* aligned), to copy the length size data to daddr. Or, while doing normal DAX
* write operation, dax_iomap_iter() might call this to do the copy of either
* start or end unaligned address. In the latter case the rest of the copy of
* aligned ranges is taken care by dax_iomap_iter() itself.
* If the srcmap contains invalid data, such as HOLE and UNWRITTEN, zero the
* area to make sure no old data remains.
*/
static int dax_iomap_copy_around(loff_t pos, uint64_t length, size_t align_size,
const struct iomap *srcmap, void *daddr)
{
loff_t head_off = pos & (align_size - 1);
size_t size = ALIGN(head_off + length, align_size);
loff_t end = pos + length;
loff_t pg_end = round_up(end, align_size);
/* copy_all is usually in page fault case */
bool copy_all = head_off == 0 && end == pg_end;
/* zero the edges if srcmap is a HOLE or IOMAP_UNWRITTEN */
bool zero_edge = srcmap->flags & IOMAP_F_SHARED ||
srcmap->type == IOMAP_UNWRITTEN;
void *saddr = 0;
int ret = 0;
if (!zero_edge) {
ret = dax_iomap_direct_access(srcmap, pos, size, &saddr, NULL);
if (ret)
return dax_mem2blk_err(ret);
}
if (copy_all) {
if (zero_edge)
memset(daddr, 0, size);
else
ret = copy_mc_to_kernel(daddr, saddr, length);
goto out;
}
/* Copy the head part of the range */
if (head_off) {
if (zero_edge)
memset(daddr, 0, head_off);
else {
ret = copy_mc_to_kernel(daddr, saddr, head_off);
if (ret)
return -EIO;
}
}
/* Copy the tail part of the range */
if (end < pg_end) {
loff_t tail_off = head_off + length;
loff_t tail_len = pg_end - end;
if (zero_edge)
memset(daddr + tail_off, 0, tail_len);
else {
ret = copy_mc_to_kernel(daddr + tail_off,
saddr + tail_off, tail_len);
if (ret)
return -EIO;
}
}
out:
if (zero_edge)
dax_flush(srcmap->dax_dev, daddr, size);
return ret ? -EIO : 0;
}
/*
* The user has performed a load from a hole in the file. Allocating a new
* page in the file would cause excessive storage usage for workloads with
* sparse files. Instead we insert a read-only mapping of the 4k zero page.
* If this page is ever written to we will re-fault and change the mapping to
* point to real DAX storage instead.
*/
static vm_fault_t dax_load_hole(struct xa_state *xas, struct vm_fault *vmf,
const struct iomap_iter *iter, void **entry)
{
struct inode *inode = iter->inode;
unsigned long vaddr = vmf->address;
pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr));
vm_fault_t ret;
*entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE);
ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
trace_dax_load_hole(inode, vmf, ret);
return ret;
}
#ifdef CONFIG_FS_DAX_PMD
static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
const struct iomap_iter *iter, void **entry)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
unsigned long pmd_addr = vmf->address & PMD_MASK;
struct vm_area_struct *vma = vmf->vma;
struct inode *inode = mapping->host;
pgtable_t pgtable = NULL;
struct page *zero_page;
spinlock_t *ptl;
pmd_t pmd_entry;
pfn_t pfn;
zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm);
if (unlikely(!zero_page))
goto fallback;
pfn = page_to_pfn_t(zero_page);
*entry = dax_insert_entry(xas, vmf, iter, *entry, pfn,
DAX_PMD | DAX_ZERO_PAGE);
if (arch_needs_pgtable_deposit()) {
pgtable = pte_alloc_one(vma->vm_mm);
if (!pgtable)
return VM_FAULT_OOM;
}
ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
if (!pmd_none(*(vmf->pmd))) {
spin_unlock(ptl);
goto fallback;
}
if (pgtable) {
pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
mm_inc_nr_ptes(vma->vm_mm);
}
pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot);
pmd_entry = pmd_mkhuge(pmd_entry);
set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry);
spin_unlock(ptl);
trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry);
return VM_FAULT_NOPAGE;
fallback:
if (pgtable)
pte_free(vma->vm_mm, pgtable);
trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry);
return VM_FAULT_FALLBACK;
}
#else
static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
const struct iomap_iter *iter, void **entry)
{
return VM_FAULT_FALLBACK;
}
#endif /* CONFIG_FS_DAX_PMD */
static s64 dax_unshare_iter(struct iomap_iter *iter)
{
struct iomap *iomap = &iter->iomap;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
loff_t pos = iter->pos;
loff_t length = iomap_length(iter);
int id = 0;
s64 ret = 0;
void *daddr = NULL, *saddr = NULL;
/* don't bother with blocks that are not shared to start with */
if (!(iomap->flags & IOMAP_F_SHARED))
return length;
id = dax_read_lock();
ret = dax_iomap_direct_access(iomap, pos, length, &daddr, NULL);
if (ret < 0)
goto out_unlock;
/* zero the distance if srcmap is HOLE or UNWRITTEN */
if (srcmap->flags & IOMAP_F_SHARED || srcmap->type == IOMAP_UNWRITTEN) {
memset(daddr, 0, length);
dax_flush(iomap->dax_dev, daddr, length);
ret = length;
goto out_unlock;
}
ret = dax_iomap_direct_access(srcmap, pos, length, &saddr, NULL);
if (ret < 0)
goto out_unlock;
if (copy_mc_to_kernel(daddr, saddr, length) == 0)
ret = length;
else
ret = -EIO;
out_unlock:
dax_read_unlock(id);
return dax_mem2blk_err(ret);
}
int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
const struct iomap_ops *ops)
{
struct iomap_iter iter = {
.inode = inode,
.pos = pos,
.len = len,
.flags = IOMAP_WRITE | IOMAP_UNSHARE | IOMAP_DAX,
};
int ret;
while ((ret = iomap_iter(&iter, ops)) > 0)
iter.processed = dax_unshare_iter(&iter);
return ret;
}
EXPORT_SYMBOL_GPL(dax_file_unshare);
static int dax_memzero(struct iomap_iter *iter, loff_t pos, size_t size)
{
const struct iomap *iomap = &iter->iomap;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
unsigned offset = offset_in_page(pos);
pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
void *kaddr;
long ret;
ret = dax_direct_access(iomap->dax_dev, pgoff, 1, DAX_ACCESS, &kaddr,
NULL);
if (ret < 0)
return dax_mem2blk_err(ret);
memset(kaddr + offset, 0, size);
if (iomap->flags & IOMAP_F_SHARED)
ret = dax_iomap_copy_around(pos, size, PAGE_SIZE, srcmap,
kaddr);
else
dax_flush(iomap->dax_dev, kaddr + offset, size);
return ret;
}
static s64 dax_zero_iter(struct iomap_iter *iter, bool *did_zero)
{
const struct iomap *iomap = &iter->iomap;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
loff_t pos = iter->pos;
u64 length = iomap_length(iter);
s64 written = 0;
/* already zeroed? we're done. */
if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN)
return length;
/*
* invalidate the pages whose sharing state is to be changed
* because of CoW.
*/
if (iomap->flags & IOMAP_F_SHARED)
invalidate_inode_pages2_range(iter->inode->i_mapping,
pos >> PAGE_SHIFT,
(pos + length - 1) >> PAGE_SHIFT);
do {
unsigned offset = offset_in_page(pos);
unsigned size = min_t(u64, PAGE_SIZE - offset, length);
pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
long rc;
int id;
id = dax_read_lock();
if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE)
rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1);
else
rc = dax_memzero(iter, pos, size);
dax_read_unlock(id);
if (rc < 0)
return rc;
pos += size;
length -= size;
written += size;
} while (length > 0);
if (did_zero)
*did_zero = true;
return written;
}
int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
const struct iomap_ops *ops)
{
struct iomap_iter iter = {
.inode = inode,
.pos = pos,
.len = len,
.flags = IOMAP_DAX | IOMAP_ZERO,
};
int ret;
while ((ret = iomap_iter(&iter, ops)) > 0)
iter.processed = dax_zero_iter(&iter, did_zero);
return ret;
}
EXPORT_SYMBOL_GPL(dax_zero_range);
int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
const struct iomap_ops *ops)
{
unsigned int blocksize = i_blocksize(inode);
unsigned int off = pos & (blocksize - 1);
/* Block boundary? Nothing to do */
if (!off)
return 0;
return dax_zero_range(inode, pos, blocksize - off, did_zero, ops);
}
EXPORT_SYMBOL_GPL(dax_truncate_page);
static loff_t dax_iomap_iter(const struct iomap_iter *iomi,
struct iov_iter *iter)
{
const struct iomap *iomap = &iomi->iomap;
const struct iomap *srcmap = iomap_iter_srcmap(iomi);
loff_t length = iomap_length(iomi);
loff_t pos = iomi->pos;
struct dax_device *dax_dev = iomap->dax_dev;
loff_t end = pos + length, done = 0;
bool write = iov_iter_rw(iter) == WRITE;
bool cow = write && iomap->flags & IOMAP_F_SHARED;
ssize_t ret = 0;
size_t xfer;
int id;
if (!write) {
end = min(end, i_size_read(iomi->inode));
if (pos >= end)
return 0;
if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN)
return iov_iter_zero(min(length, end - pos), iter);
}
/*
* In DAX mode, enforce either pure overwrites of written extents, or
* writes to unwritten extents as part of a copy-on-write operation.
*/
if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED &&
!(iomap->flags & IOMAP_F_SHARED)))
return -EIO;
/*
* Write can allocate block for an area which has a hole page mapped
* into page tables. We have to tear down these mappings so that data
* written by write(2) is visible in mmap.
*/
if (iomap->flags & IOMAP_F_NEW || cow) {
/*
* Filesystem allows CoW on non-shared extents. The src extents
* may have been mmapped with dirty mark before. To be able to
* invalidate its dax entries, we need to clear the dirty mark
* in advance.
*/
if (cow)
__dax_clear_dirty_range(iomi->inode->i_mapping,
pos >> PAGE_SHIFT,
(end - 1) >> PAGE_SHIFT);
invalidate_inode_pages2_range(iomi->inode->i_mapping,
pos >> PAGE_SHIFT,
(end - 1) >> PAGE_SHIFT);
}
id = dax_read_lock();
while (pos < end) {
unsigned offset = pos & (PAGE_SIZE - 1);
const size_t size = ALIGN(length + offset, PAGE_SIZE);
pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
ssize_t map_len;
bool recovery = false;
void *kaddr;
if (fatal_signal_pending(current)) {
ret = -EINTR;
break;
}
map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size),
DAX_ACCESS, &kaddr, NULL);
if (map_len == -EHWPOISON && iov_iter_rw(iter) == WRITE) {
map_len = dax_direct_access(dax_dev, pgoff,
PHYS_PFN(size), DAX_RECOVERY_WRITE,
&kaddr, NULL);
if (map_len > 0)
recovery = true;
}
if (map_len < 0) {
ret = dax_mem2blk_err(map_len);
break;
}
if (cow) {
ret = dax_iomap_copy_around(pos, length, PAGE_SIZE,
srcmap, kaddr);
if (ret)
break;
}
map_len = PFN_PHYS(map_len);
kaddr += offset;
map_len -= offset;
if (map_len > end - pos)
map_len = end - pos;
if (recovery)
xfer = dax_recovery_write(dax_dev, pgoff, kaddr,
map_len, iter);
else if (write)
xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr,
map_len, iter);
else
xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr,
map_len, iter);
pos += xfer;
length -= xfer;
done += xfer;
if (xfer == 0)
ret = -EFAULT;
if (xfer < map_len)
break;
}
dax_read_unlock(id);
return done ? done : ret;
}
/**
* dax_iomap_rw - Perform I/O to a DAX file
* @iocb: The control block for this I/O
* @iter: The addresses to do I/O from or to
* @ops: iomap ops passed from the file system
*
* This function performs read and write operations to directly mapped
* persistent memory. The callers needs to take care of read/write exclusion
* and evicting any page cache pages in the region under I/O.
*/
ssize_t
dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops)
{
struct iomap_iter iomi = {
.inode = iocb->ki_filp->f_mapping->host,
.pos = iocb->ki_pos,
.len = iov_iter_count(iter),
.flags = IOMAP_DAX,
};
loff_t done = 0;
int ret;
if (!iomi.len)
return 0;
if (iov_iter_rw(iter) == WRITE) {
lockdep_assert_held_write(&iomi.inode->i_rwsem);
iomi.flags |= IOMAP_WRITE;
} else {
lockdep_assert_held(&iomi.inode->i_rwsem);
}
if (iocb->ki_flags & IOCB_NOWAIT)
iomi.flags |= IOMAP_NOWAIT;
while ((ret = iomap_iter(&iomi, ops)) > 0)
iomi.processed = dax_iomap_iter(&iomi, iter);
done = iomi.pos - iocb->ki_pos;
iocb->ki_pos = iomi.pos;
return done ? done : ret;
}
EXPORT_SYMBOL_GPL(dax_iomap_rw);
static vm_fault_t dax_fault_return(int error)
{
if (error == 0)
return VM_FAULT_NOPAGE;
return vmf_error(error);
}
/*
* When handling a synchronous page fault and the inode need a fsync, we can
* insert the PTE/PMD into page tables only after that fsync happened. Skip
* insertion for now and return the pfn so that caller can insert it after the
* fsync is done.
*/
static vm_fault_t dax_fault_synchronous_pfnp(pfn_t *pfnp, pfn_t pfn)
{
if (WARN_ON_ONCE(!pfnp))
return VM_FAULT_SIGBUS;
*pfnp = pfn;
return VM_FAULT_NEEDDSYNC;
}
static vm_fault_t dax_fault_cow_page(struct vm_fault *vmf,
const struct iomap_iter *iter)
{
vm_fault_t ret;
int error = 0;
switch (iter->iomap.type) {
case IOMAP_HOLE:
case IOMAP_UNWRITTEN:
clear_user_highpage(vmf->cow_page, vmf->address);
break;
case IOMAP_MAPPED:
error = copy_cow_page_dax(vmf, iter);
break;
default:
WARN_ON_ONCE(1);
error = -EIO;
break;
}
if (error)
return dax_fault_return(error);
__SetPageUptodate(vmf->cow_page);
ret = finish_fault(vmf);
if (!ret)
return VM_FAULT_DONE_COW;
return ret;
}
/**
* dax_fault_iter - Common actor to handle pfn insertion in PTE/PMD fault.
* @vmf: vm fault instance
* @iter: iomap iter
* @pfnp: pfn to be returned
* @xas: the dax mapping tree of a file
* @entry: an unlocked dax entry to be inserted
* @pmd: distinguish whether it is a pmd fault
*/
static vm_fault_t dax_fault_iter(struct vm_fault *vmf,
const struct iomap_iter *iter, pfn_t *pfnp,
struct xa_state *xas, void **entry, bool pmd)
{
const struct iomap *iomap = &iter->iomap;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
size_t size = pmd ? PMD_SIZE : PAGE_SIZE;
loff_t pos = (loff_t)xas->xa_index << PAGE_SHIFT;
bool write = iter->flags & IOMAP_WRITE;
unsigned long entry_flags = pmd ? DAX_PMD : 0;
int err = 0;
pfn_t pfn;
void *kaddr;
if (!pmd && vmf->cow_page)
return dax_fault_cow_page(vmf, iter);
/* if we are reading UNWRITTEN and HOLE, return a hole. */
if (!write &&
(iomap->type == IOMAP_UNWRITTEN || iomap->type == IOMAP_HOLE)) {
if (!pmd)
return dax_load_hole(xas, vmf, iter, entry);
return dax_pmd_load_hole(xas, vmf, iter, entry);
}
if (iomap->type != IOMAP_MAPPED && !(iomap->flags & IOMAP_F_SHARED)) {
WARN_ON_ONCE(1);
return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS;
}
err = dax_iomap_direct_access(iomap, pos, size, &kaddr, &pfn);
if (err)
return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err);
*entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, entry_flags);
if (write && iomap->flags & IOMAP_F_SHARED) {
err = dax_iomap_copy_around(pos, size, size, srcmap, kaddr);
if (err)
return dax_fault_return(err);
}
if (dax_fault_is_synchronous(iter, vmf->vma))
return dax_fault_synchronous_pfnp(pfnp, pfn);
/* insert PMD pfn */
if (pmd)
return vmf_insert_pfn_pmd(vmf, pfn, write);
/* insert PTE pfn */
if (write)
return vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
return vmf_insert_mixed(vmf->vma, vmf->address, pfn);
}
static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
int *iomap_errp, const struct iomap_ops *ops)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
XA_STATE(xas, &mapping->i_pages, vmf->pgoff);
struct iomap_iter iter = {
.inode = mapping->host,
.pos = (loff_t)vmf->pgoff << PAGE_SHIFT,
.len = PAGE_SIZE,
.flags = IOMAP_DAX | IOMAP_FAULT,
};
vm_fault_t ret = 0;
void *entry;
int error;
trace_dax_pte_fault(iter.inode, vmf, ret);
/*
* Check whether offset isn't beyond end of file now. Caller is supposed
* to hold locks serializing us with truncate / punch hole so this is
* a reliable test.
*/
if (iter.pos >= i_size_read(iter.inode)) {
ret = VM_FAULT_SIGBUS;
goto out;
}
if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page)
iter.flags |= IOMAP_WRITE;
entry = grab_mapping_entry(&xas, mapping, 0);
if (xa_is_internal(entry)) {
ret = xa_to_internal(entry);
goto out;
}
/*
* It is possible, particularly with mixed reads & writes to private
* mappings, that we have raced with a PMD fault that overlaps with
* the PTE we need to set up. If so just return and the fault will be
* retried.
*/
if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) {
ret = VM_FAULT_NOPAGE;
goto unlock_entry;
}
while ((error = iomap_iter(&iter, ops)) > 0) {
if (WARN_ON_ONCE(iomap_length(&iter) < PAGE_SIZE)) {
iter.processed = -EIO; /* fs corruption? */
continue;
}
ret = dax_fault_iter(vmf, &iter, pfnp, &xas, &entry, false);
if (ret != VM_FAULT_SIGBUS &&
(iter.iomap.flags & IOMAP_F_NEW)) {
count_vm_event(PGMAJFAULT);
count_memcg_event_mm(vmf->vma->vm_mm, PGMAJFAULT);
ret |= VM_FAULT_MAJOR;
}
if (!(ret & VM_FAULT_ERROR))
iter.processed = PAGE_SIZE;
}
if (iomap_errp)
*iomap_errp = error;
if (!ret && error)
ret = dax_fault_return(error);
unlock_entry:
dax_unlock_entry(&xas, entry);
out:
trace_dax_pte_fault_done(iter.inode, vmf, ret);
return ret;
}
#ifdef CONFIG_FS_DAX_PMD
static bool dax_fault_check_fallback(struct vm_fault *vmf, struct xa_state *xas,
pgoff_t max_pgoff)
{
unsigned long pmd_addr = vmf->address & PMD_MASK;
bool write = vmf->flags & FAULT_FLAG_WRITE;
/*
* Make sure that the faulting address's PMD offset (color) matches
* the PMD offset from the start of the file. This is necessary so
* that a PMD range in the page table overlaps exactly with a PMD
* range in the page cache.
*/
if ((vmf->pgoff & PG_PMD_COLOUR) !=
((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR))
return true;
/* Fall back to PTEs if we're going to COW */
if (write && !(vmf->vma->vm_flags & VM_SHARED))
return true;
/* If the PMD would extend outside the VMA */
if (pmd_addr < vmf->vma->vm_start)
return true;
if ((pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
return true;
/* If the PMD would extend beyond the file size */
if ((xas->xa_index | PG_PMD_COLOUR) >= max_pgoff)
return true;
return false;
}
static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
const struct iomap_ops *ops)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER);
struct iomap_iter iter = {
.inode = mapping->host,
.len = PMD_SIZE,
.flags = IOMAP_DAX | IOMAP_FAULT,
};
vm_fault_t ret = VM_FAULT_FALLBACK;
pgoff_t max_pgoff;
void *entry;
if (vmf->flags & FAULT_FLAG_WRITE)
iter.flags |= IOMAP_WRITE;
/*
* Check whether offset isn't beyond end of file now. Caller is
* supposed to hold locks serializing us with truncate / punch hole so
* this is a reliable test.
*/
max_pgoff = DIV_ROUND_UP(i_size_read(iter.inode), PAGE_SIZE);
trace_dax_pmd_fault(iter.inode, vmf, max_pgoff, 0);
if (xas.xa_index >= max_pgoff) {
ret = VM_FAULT_SIGBUS;
goto out;
}
if (dax_fault_check_fallback(vmf, &xas, max_pgoff))
goto fallback;
/*
* grab_mapping_entry() will make sure we get an empty PMD entry,
* a zero PMD entry or a DAX PMD. If it can't (because a PTE
* entry is already in the array, for instance), it will return
* VM_FAULT_FALLBACK.
*/
entry = grab_mapping_entry(&xas, mapping, PMD_ORDER);
if (xa_is_internal(entry)) {
ret = xa_to_internal(entry);
goto fallback;
}
/*
* It is possible, particularly with mixed reads & writes to private
* mappings, that we have raced with a PTE fault that overlaps with
* the PMD we need to set up. If so just return and the fault will be
* retried.
*/
if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) &&
!pmd_devmap(*vmf->pmd)) {
ret = 0;
goto unlock_entry;
}
iter.pos = (loff_t)xas.xa_index << PAGE_SHIFT;
while (iomap_iter(&iter, ops) > 0) {
if (iomap_length(&iter) < PMD_SIZE)
continue; /* actually breaks out of the loop */
ret = dax_fault_iter(vmf, &iter, pfnp, &xas, &entry, true);
if (ret != VM_FAULT_FALLBACK)
iter.processed = PMD_SIZE;
}
unlock_entry:
dax_unlock_entry(&xas, entry);
fallback:
if (ret == VM_FAULT_FALLBACK) {
split_huge_pmd(vmf->vma, vmf->pmd, vmf->address);
count_vm_event(THP_FAULT_FALLBACK);
}
out:
trace_dax_pmd_fault_done(iter.inode, vmf, max_pgoff, ret);
return ret;
}
#else
static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
const struct iomap_ops *ops)
{
return VM_FAULT_FALLBACK;
}
#endif /* CONFIG_FS_DAX_PMD */
/**
* dax_iomap_fault - handle a page fault on a DAX file
* @vmf: The description of the fault
* @order: Order of the page to fault in
* @pfnp: PFN to insert for synchronous faults if fsync is required
* @iomap_errp: Storage for detailed error code in case of error
* @ops: Iomap ops passed from the file system
*
* When a page fault occurs, filesystems may call this helper in
* their fault handler for DAX files. dax_iomap_fault() assumes the caller
* has done all the necessary locking for page fault to proceed
* successfully.
*/
vm_fault_t dax_iomap_fault(struct vm_fault *vmf, unsigned int order,
pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops)
{
if (order == 0)
return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops);
else if (order == PMD_ORDER)
return dax_iomap_pmd_fault(vmf, pfnp, ops);
else
return VM_FAULT_FALLBACK;
}
EXPORT_SYMBOL_GPL(dax_iomap_fault);
/*
* dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables
* @vmf: The description of the fault
* @pfn: PFN to insert
* @order: Order of entry to insert.
*
* This function inserts a writeable PTE or PMD entry into the page tables
* for an mmaped DAX file. It also marks the page cache entry as dirty.
*/
static vm_fault_t
dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, order);
void *entry;
vm_fault_t ret;
xas_lock_irq(&xas);
entry = get_unlocked_entry(&xas, order);
/* Did we race with someone splitting entry or so? */
if (!entry || dax_is_conflict(entry) ||
(order == 0 && !dax_is_pte_entry(entry))) {
put_unlocked_entry(&xas, entry, WAKE_NEXT);
xas_unlock_irq(&xas);
trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf,
VM_FAULT_NOPAGE);
return VM_FAULT_NOPAGE;
}
xas_set_mark(&xas, PAGECACHE_TAG_DIRTY);
dax_lock_entry(&xas, entry);
xas_unlock_irq(&xas);
if (order == 0)
ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
#ifdef CONFIG_FS_DAX_PMD
else if (order == PMD_ORDER)
ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE);
#endif
else
ret = VM_FAULT_FALLBACK;
dax_unlock_entry(&xas, entry);
trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret);
return ret;
}
/**
* dax_finish_sync_fault - finish synchronous page fault
* @vmf: The description of the fault
* @order: Order of entry to be inserted
* @pfn: PFN to insert
*
* This function ensures that the file range touched by the page fault is
* stored persistently on the media and handles inserting of appropriate page
* table entry.
*/
vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, unsigned int order,
pfn_t pfn)
{
int err;
loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT;
size_t len = PAGE_SIZE << order;
err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1);
if (err)
return VM_FAULT_SIGBUS;
return dax_insert_pfn_mkwrite(vmf, pfn, order);
}
EXPORT_SYMBOL_GPL(dax_finish_sync_fault);
static loff_t dax_range_compare_iter(struct iomap_iter *it_src,
struct iomap_iter *it_dest, u64 len, bool *same)
{
const struct iomap *smap = &it_src->iomap;
const struct iomap *dmap = &it_dest->iomap;
loff_t pos1 = it_src->pos, pos2 = it_dest->pos;
void *saddr, *daddr;
int id, ret;
len = min(len, min(smap->length, dmap->length));
if (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE) {
*same = true;
return len;
}
if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) {
*same = false;
return 0;
}
id = dax_read_lock();
ret = dax_iomap_direct_access(smap, pos1, ALIGN(pos1 + len, PAGE_SIZE),
&saddr, NULL);
if (ret < 0)
goto out_unlock;
ret = dax_iomap_direct_access(dmap, pos2, ALIGN(pos2 + len, PAGE_SIZE),
&daddr, NULL);
if (ret < 0)
goto out_unlock;
*same = !memcmp(saddr, daddr, len);
if (!*same)
len = 0;
dax_read_unlock(id);
return len;
out_unlock:
dax_read_unlock(id);
return -EIO;
}
int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
struct inode *dst, loff_t dstoff, loff_t len, bool *same,
const struct iomap_ops *ops)
{
struct iomap_iter src_iter = {
.inode = src,
.pos = srcoff,
.len = len,
.flags = IOMAP_DAX,
};
struct iomap_iter dst_iter = {
.inode = dst,
.pos = dstoff,
.len = len,
.flags = IOMAP_DAX,
};
int ret, compared = 0;
while ((ret = iomap_iter(&src_iter, ops)) > 0 &&
(ret = iomap_iter(&dst_iter, ops)) > 0) {
compared = dax_range_compare_iter(&src_iter, &dst_iter,
min(src_iter.len, dst_iter.len), same);
if (compared < 0)
return ret;
src_iter.processed = dst_iter.processed = compared;
}
return ret;
}
int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t *len, unsigned int remap_flags,
const struct iomap_ops *ops)
{
return __generic_remap_file_range_prep(file_in, pos_in, file_out,
pos_out, len, remap_flags, ops);
}
EXPORT_SYMBOL_GPL(dax_remap_file_range_prep);
| linux-master | fs/dax.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/open.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/fsnotify.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/namei.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>
#include <linux/securebits.h>
#include <linux/security.h>
#include <linux/mount.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/fs.h>
#include <linux/personality.h>
#include <linux/pagemap.h>
#include <linux/syscalls.h>
#include <linux/rcupdate.h>
#include <linux/audit.h>
#include <linux/falloc.h>
#include <linux/fs_struct.h>
#include <linux/ima.h>
#include <linux/dnotify.h>
#include <linux/compat.h>
#include <linux/mnt_idmapping.h>
#include <linux/filelock.h>
#include "internal.h"
int do_truncate(struct mnt_idmap *idmap, struct dentry *dentry,
loff_t length, unsigned int time_attrs, struct file *filp)
{
int ret;
struct iattr newattrs;
/* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
if (length < 0)
return -EINVAL;
newattrs.ia_size = length;
newattrs.ia_valid = ATTR_SIZE | time_attrs;
if (filp) {
newattrs.ia_file = filp;
newattrs.ia_valid |= ATTR_FILE;
}
/* Remove suid, sgid, and file capabilities on truncate too */
ret = dentry_needs_remove_privs(idmap, dentry);
if (ret < 0)
return ret;
if (ret)
newattrs.ia_valid |= ret | ATTR_FORCE;
inode_lock(dentry->d_inode);
/* Note any delegations or leases have already been broken: */
ret = notify_change(idmap, dentry, &newattrs, NULL);
inode_unlock(dentry->d_inode);
return ret;
}
long vfs_truncate(const struct path *path, loff_t length)
{
struct mnt_idmap *idmap;
struct inode *inode;
long error;
inode = path->dentry->d_inode;
/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
if (S_ISDIR(inode->i_mode))
return -EISDIR;
if (!S_ISREG(inode->i_mode))
return -EINVAL;
error = mnt_want_write(path->mnt);
if (error)
goto out;
idmap = mnt_idmap(path->mnt);
error = inode_permission(idmap, inode, MAY_WRITE);
if (error)
goto mnt_drop_write_and_out;
error = -EPERM;
if (IS_APPEND(inode))
goto mnt_drop_write_and_out;
error = get_write_access(inode);
if (error)
goto mnt_drop_write_and_out;
/*
* Make sure that there are no leases. get_write_access() protects
* against the truncate racing with a lease-granting setlease().
*/
error = break_lease(inode, O_WRONLY);
if (error)
goto put_write_and_out;
error = security_path_truncate(path);
if (!error)
error = do_truncate(idmap, path->dentry, length, 0, NULL);
put_write_and_out:
put_write_access(inode);
mnt_drop_write_and_out:
mnt_drop_write(path->mnt);
out:
return error;
}
EXPORT_SYMBOL_GPL(vfs_truncate);
long do_sys_truncate(const char __user *pathname, loff_t length)
{
unsigned int lookup_flags = LOOKUP_FOLLOW;
struct path path;
int error;
if (length < 0) /* sorry, but loff_t says... */
return -EINVAL;
retry:
error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
if (!error) {
error = vfs_truncate(&path, length);
path_put(&path);
}
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
return error;
}
SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
{
return do_sys_truncate(path, length);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
{
return do_sys_truncate(path, length);
}
#endif
long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
{
struct inode *inode;
struct dentry *dentry;
struct fd f;
int error;
error = -EINVAL;
if (length < 0)
goto out;
error = -EBADF;
f = fdget(fd);
if (!f.file)
goto out;
/* explicitly opened as large or we are on 64-bit box */
if (f.file->f_flags & O_LARGEFILE)
small = 0;
dentry = f.file->f_path.dentry;
inode = dentry->d_inode;
error = -EINVAL;
if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
goto out_putf;
error = -EINVAL;
/* Cannot ftruncate over 2^31 bytes without large file support */
if (small && length > MAX_NON_LFS)
goto out_putf;
error = -EPERM;
/* Check IS_APPEND on real upper inode */
if (IS_APPEND(file_inode(f.file)))
goto out_putf;
sb_start_write(inode->i_sb);
error = security_file_truncate(f.file);
if (!error)
error = do_truncate(file_mnt_idmap(f.file), dentry, length,
ATTR_MTIME | ATTR_CTIME, f.file);
sb_end_write(inode->i_sb);
out_putf:
fdput(f);
out:
return error;
}
SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
{
return do_sys_ftruncate(fd, length, 1);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
{
return do_sys_ftruncate(fd, length, 1);
}
#endif
/* LFS versions of truncate are only needed on 32 bit machines */
#if BITS_PER_LONG == 32
SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
{
return do_sys_truncate(path, length);
}
SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
{
return do_sys_ftruncate(fd, length, 0);
}
#endif /* BITS_PER_LONG == 32 */
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_TRUNCATE64)
COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, pathname,
compat_arg_u64_dual(length))
{
return ksys_truncate(pathname, compat_arg_u64_glue(length));
}
#endif
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FTRUNCATE64)
COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd,
compat_arg_u64_dual(length))
{
return ksys_ftruncate(fd, compat_arg_u64_glue(length));
}
#endif
int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
{
struct inode *inode = file_inode(file);
long ret;
if (offset < 0 || len <= 0)
return -EINVAL;
/* Return error if mode is not supported */
if (mode & ~FALLOC_FL_SUPPORTED_MASK)
return -EOPNOTSUPP;
/* Punch hole and zero range are mutually exclusive */
if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
(FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
return -EOPNOTSUPP;
/* Punch hole must have keep size set */
if ((mode & FALLOC_FL_PUNCH_HOLE) &&
!(mode & FALLOC_FL_KEEP_SIZE))
return -EOPNOTSUPP;
/* Collapse range should only be used exclusively. */
if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
(mode & ~FALLOC_FL_COLLAPSE_RANGE))
return -EINVAL;
/* Insert range should only be used exclusively. */
if ((mode & FALLOC_FL_INSERT_RANGE) &&
(mode & ~FALLOC_FL_INSERT_RANGE))
return -EINVAL;
/* Unshare range should only be used with allocate mode. */
if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
(mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
return -EINVAL;
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
/*
* We can only allow pure fallocate on append only files
*/
if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
return -EPERM;
if (IS_IMMUTABLE(inode))
return -EPERM;
/*
* We cannot allow any fallocate operation on an active swapfile
*/
if (IS_SWAPFILE(inode))
return -ETXTBSY;
/*
* Revalidate the write permissions, in case security policy has
* changed since the files were opened.
*/
ret = security_file_permission(file, MAY_WRITE);
if (ret)
return ret;
if (S_ISFIFO(inode->i_mode))
return -ESPIPE;
if (S_ISDIR(inode->i_mode))
return -EISDIR;
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
return -ENODEV;
/* Check for wrap through zero too */
if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
return -EFBIG;
if (!file->f_op->fallocate)
return -EOPNOTSUPP;
file_start_write(file);
ret = file->f_op->fallocate(file, mode, offset, len);
/*
* Create inotify and fanotify events.
*
* To keep the logic simple always create events if fallocate succeeds.
* This implies that events are even created if the file size remains
* unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
*/
if (ret == 0)
fsnotify_modify(file);
file_end_write(file);
return ret;
}
EXPORT_SYMBOL_GPL(vfs_fallocate);
int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len)
{
struct fd f = fdget(fd);
int error = -EBADF;
if (f.file) {
error = vfs_fallocate(f.file, mode, offset, len);
fdput(f);
}
return error;
}
SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
{
return ksys_fallocate(fd, mode, offset, len);
}
#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FALLOCATE)
COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode, compat_arg_u64_dual(offset),
compat_arg_u64_dual(len))
{
return ksys_fallocate(fd, mode, compat_arg_u64_glue(offset),
compat_arg_u64_glue(len));
}
#endif
/*
* access() needs to use the real uid/gid, not the effective uid/gid.
* We do this by temporarily clearing all FS-related capabilities and
* switching the fsuid/fsgid around to the real ones.
*
* Creating new credentials is expensive, so we try to skip doing it,
* which we can if the result would match what we already got.
*/
static bool access_need_override_creds(int flags)
{
const struct cred *cred;
if (flags & AT_EACCESS)
return false;
cred = current_cred();
if (!uid_eq(cred->fsuid, cred->uid) ||
!gid_eq(cred->fsgid, cred->gid))
return true;
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
kuid_t root_uid = make_kuid(cred->user_ns, 0);
if (!uid_eq(cred->uid, root_uid)) {
if (!cap_isclear(cred->cap_effective))
return true;
} else {
if (!cap_isidentical(cred->cap_effective,
cred->cap_permitted))
return true;
}
}
return false;
}
static const struct cred *access_override_creds(void)
{
const struct cred *old_cred;
struct cred *override_cred;
override_cred = prepare_creds();
if (!override_cred)
return NULL;
/*
* XXX access_need_override_creds performs checks in hopes of skipping
* this work. Make sure it stays in sync if making any changes in this
* routine.
*/
override_cred->fsuid = override_cred->uid;
override_cred->fsgid = override_cred->gid;
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
/* Clear the capabilities if we switch to a non-root user */
kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
if (!uid_eq(override_cred->uid, root_uid))
cap_clear(override_cred->cap_effective);
else
override_cred->cap_effective =
override_cred->cap_permitted;
}
/*
* The new set of credentials can *only* be used in
* task-synchronous circumstances, and does not need
* RCU freeing, unless somebody then takes a separate
* reference to it.
*
* NOTE! This is _only_ true because this credential
* is used purely for override_creds() that installs
* it as the subjective cred. Other threads will be
* accessing ->real_cred, not the subjective cred.
*
* If somebody _does_ make a copy of this (using the
* 'get_current_cred()' function), that will clear the
* non_rcu field, because now that other user may be
* expecting RCU freeing. But normal thread-synchronous
* cred accesses will keep things non-RCY.
*/
override_cred->non_rcu = 1;
old_cred = override_creds(override_cred);
/* override_cred() gets its own ref */
put_cred(override_cred);
return old_cred;
}
static long do_faccessat(int dfd, const char __user *filename, int mode, int flags)
{
struct path path;
struct inode *inode;
int res;
unsigned int lookup_flags = LOOKUP_FOLLOW;
const struct cred *old_cred = NULL;
if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
return -EINVAL;
if (flags & ~(AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
return -EINVAL;
if (flags & AT_SYMLINK_NOFOLLOW)
lookup_flags &= ~LOOKUP_FOLLOW;
if (flags & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
if (access_need_override_creds(flags)) {
old_cred = access_override_creds();
if (!old_cred)
return -ENOMEM;
}
retry:
res = user_path_at(dfd, filename, lookup_flags, &path);
if (res)
goto out;
inode = d_backing_inode(path.dentry);
if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
/*
* MAY_EXEC on regular files is denied if the fs is mounted
* with the "noexec" flag.
*/
res = -EACCES;
if (path_noexec(&path))
goto out_path_release;
}
res = inode_permission(mnt_idmap(path.mnt), inode, mode | MAY_ACCESS);
/* SuS v2 requires we report a read only fs too */
if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
goto out_path_release;
/*
* This is a rare case where using __mnt_is_readonly()
* is OK without a mnt_want/drop_write() pair. Since
* no actual write to the fs is performed here, we do
* not need to telegraph to that to anyone.
*
* By doing this, we accept that this access is
* inherently racy and know that the fs may change
* state before we even see this result.
*/
if (__mnt_is_readonly(path.mnt))
res = -EROFS;
out_path_release:
path_put(&path);
if (retry_estale(res, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out:
if (old_cred)
revert_creds(old_cred);
return res;
}
SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
{
return do_faccessat(dfd, filename, mode, 0);
}
SYSCALL_DEFINE4(faccessat2, int, dfd, const char __user *, filename, int, mode,
int, flags)
{
return do_faccessat(dfd, filename, mode, flags);
}
SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
{
return do_faccessat(AT_FDCWD, filename, mode, 0);
}
SYSCALL_DEFINE1(chdir, const char __user *, filename)
{
struct path path;
int error;
unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
retry:
error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
if (error)
goto out;
error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (error)
goto dput_and_out;
set_fs_pwd(current->fs, &path);
dput_and_out:
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out:
return error;
}
SYSCALL_DEFINE1(fchdir, unsigned int, fd)
{
struct fd f = fdget_raw(fd);
int error;
error = -EBADF;
if (!f.file)
goto out;
error = -ENOTDIR;
if (!d_can_lookup(f.file->f_path.dentry))
goto out_putf;
error = file_permission(f.file, MAY_EXEC | MAY_CHDIR);
if (!error)
set_fs_pwd(current->fs, &f.file->f_path);
out_putf:
fdput(f);
out:
return error;
}
SYSCALL_DEFINE1(chroot, const char __user *, filename)
{
struct path path;
int error;
unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
retry:
error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
if (error)
goto out;
error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
if (error)
goto dput_and_out;
error = -EPERM;
if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
goto dput_and_out;
error = security_path_chroot(&path);
if (error)
goto dput_and_out;
set_fs_root(current->fs, &path);
error = 0;
dput_and_out:
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out:
return error;
}
int chmod_common(const struct path *path, umode_t mode)
{
struct inode *inode = path->dentry->d_inode;
struct inode *delegated_inode = NULL;
struct iattr newattrs;
int error;
error = mnt_want_write(path->mnt);
if (error)
return error;
retry_deleg:
inode_lock(inode);
error = security_path_chmod(path, mode);
if (error)
goto out_unlock;
newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
error = notify_change(mnt_idmap(path->mnt), path->dentry,
&newattrs, &delegated_inode);
out_unlock:
inode_unlock(inode);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
mnt_drop_write(path->mnt);
return error;
}
int vfs_fchmod(struct file *file, umode_t mode)
{
audit_file(file);
return chmod_common(&file->f_path, mode);
}
SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
{
struct fd f = fdget(fd);
int err = -EBADF;
if (f.file) {
err = vfs_fchmod(f.file, mode);
fdput(f);
}
return err;
}
static int do_fchmodat(int dfd, const char __user *filename, umode_t mode,
unsigned int flags)
{
struct path path;
int error;
unsigned int lookup_flags;
if (unlikely(flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)))
return -EINVAL;
lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
if (flags & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
retry:
error = user_path_at(dfd, filename, lookup_flags, &path);
if (!error) {
error = chmod_common(&path, mode);
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
return error;
}
SYSCALL_DEFINE4(fchmodat2, int, dfd, const char __user *, filename,
umode_t, mode, unsigned int, flags)
{
return do_fchmodat(dfd, filename, mode, flags);
}
SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename,
umode_t, mode)
{
return do_fchmodat(dfd, filename, mode, 0);
}
SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
{
return do_fchmodat(AT_FDCWD, filename, mode, 0);
}
/*
* Check whether @kuid is valid and if so generate and set vfsuid_t in
* ia_vfsuid.
*
* Return: true if @kuid is valid, false if not.
*/
static inline bool setattr_vfsuid(struct iattr *attr, kuid_t kuid)
{
if (!uid_valid(kuid))
return false;
attr->ia_valid |= ATTR_UID;
attr->ia_vfsuid = VFSUIDT_INIT(kuid);
return true;
}
/*
* Check whether @kgid is valid and if so generate and set vfsgid_t in
* ia_vfsgid.
*
* Return: true if @kgid is valid, false if not.
*/
static inline bool setattr_vfsgid(struct iattr *attr, kgid_t kgid)
{
if (!gid_valid(kgid))
return false;
attr->ia_valid |= ATTR_GID;
attr->ia_vfsgid = VFSGIDT_INIT(kgid);
return true;
}
int chown_common(const struct path *path, uid_t user, gid_t group)
{
struct mnt_idmap *idmap;
struct user_namespace *fs_userns;
struct inode *inode = path->dentry->d_inode;
struct inode *delegated_inode = NULL;
int error;
struct iattr newattrs;
kuid_t uid;
kgid_t gid;
uid = make_kuid(current_user_ns(), user);
gid = make_kgid(current_user_ns(), group);
idmap = mnt_idmap(path->mnt);
fs_userns = i_user_ns(inode);
retry_deleg:
newattrs.ia_vfsuid = INVALID_VFSUID;
newattrs.ia_vfsgid = INVALID_VFSGID;
newattrs.ia_valid = ATTR_CTIME;
if ((user != (uid_t)-1) && !setattr_vfsuid(&newattrs, uid))
return -EINVAL;
if ((group != (gid_t)-1) && !setattr_vfsgid(&newattrs, gid))
return -EINVAL;
inode_lock(inode);
if (!S_ISDIR(inode->i_mode))
newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV |
setattr_should_drop_sgid(idmap, inode);
/* Continue to send actual fs values, not the mount values. */
error = security_path_chown(
path,
from_vfsuid(idmap, fs_userns, newattrs.ia_vfsuid),
from_vfsgid(idmap, fs_userns, newattrs.ia_vfsgid));
if (!error)
error = notify_change(idmap, path->dentry, &newattrs,
&delegated_inode);
inode_unlock(inode);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
return error;
}
int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
int flag)
{
struct path path;
int error = -EINVAL;
int lookup_flags;
if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
goto out;
lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
if (flag & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
retry:
error = user_path_at(dfd, filename, lookup_flags, &path);
if (error)
goto out;
error = mnt_want_write(path.mnt);
if (error)
goto out_release;
error = chown_common(&path, user, group);
mnt_drop_write(path.mnt);
out_release:
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
out:
return error;
}
SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
gid_t, group, int, flag)
{
return do_fchownat(dfd, filename, user, group, flag);
}
SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
{
return do_fchownat(AT_FDCWD, filename, user, group, 0);
}
SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
{
return do_fchownat(AT_FDCWD, filename, user, group,
AT_SYMLINK_NOFOLLOW);
}
int vfs_fchown(struct file *file, uid_t user, gid_t group)
{
int error;
error = mnt_want_write_file(file);
if (error)
return error;
audit_file(file);
error = chown_common(&file->f_path, user, group);
mnt_drop_write_file(file);
return error;
}
int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
{
struct fd f = fdget(fd);
int error = -EBADF;
if (f.file) {
error = vfs_fchown(f.file, user, group);
fdput(f);
}
return error;
}
SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
{
return ksys_fchown(fd, user, group);
}
static int do_dentry_open(struct file *f,
struct inode *inode,
int (*open)(struct inode *, struct file *))
{
static const struct file_operations empty_fops = {};
int error;
path_get(&f->f_path);
f->f_inode = inode;
f->f_mapping = inode->i_mapping;
f->f_wb_err = filemap_sample_wb_err(f->f_mapping);
f->f_sb_err = file_sample_sb_err(f);
if (unlikely(f->f_flags & O_PATH)) {
f->f_mode = FMODE_PATH | FMODE_OPENED;
f->f_op = &empty_fops;
return 0;
}
if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
i_readcount_inc(inode);
} else if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
error = get_write_access(inode);
if (unlikely(error))
goto cleanup_file;
error = __mnt_want_write(f->f_path.mnt);
if (unlikely(error)) {
put_write_access(inode);
goto cleanup_file;
}
f->f_mode |= FMODE_WRITER;
}
/* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
f->f_mode |= FMODE_ATOMIC_POS;
f->f_op = fops_get(inode->i_fop);
if (WARN_ON(!f->f_op)) {
error = -ENODEV;
goto cleanup_all;
}
error = security_file_open(f);
if (error)
goto cleanup_all;
error = break_lease(file_inode(f), f->f_flags);
if (error)
goto cleanup_all;
/* normally all 3 are set; ->open() can clear them if needed */
f->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
if (!open)
open = f->f_op->open;
if (open) {
error = open(inode, f);
if (error)
goto cleanup_all;
}
f->f_mode |= FMODE_OPENED;
if ((f->f_mode & FMODE_READ) &&
likely(f->f_op->read || f->f_op->read_iter))
f->f_mode |= FMODE_CAN_READ;
if ((f->f_mode & FMODE_WRITE) &&
likely(f->f_op->write || f->f_op->write_iter))
f->f_mode |= FMODE_CAN_WRITE;
if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek)
f->f_mode &= ~FMODE_LSEEK;
if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO)
f->f_mode |= FMODE_CAN_ODIRECT;
f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
f->f_iocb_flags = iocb_flags(f);
file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
if ((f->f_flags & O_DIRECT) && !(f->f_mode & FMODE_CAN_ODIRECT))
return -EINVAL;
/*
* XXX: Huge page cache doesn't support writing yet. Drop all page
* cache for this file before processing writes.
*/
if (f->f_mode & FMODE_WRITE) {
/*
* Paired with smp_mb() in collapse_file() to ensure nr_thps
* is up to date and the update to i_writecount by
* get_write_access() is visible. Ensures subsequent insertion
* of THPs into the page cache will fail.
*/
smp_mb();
if (filemap_nr_thps(inode->i_mapping)) {
struct address_space *mapping = inode->i_mapping;
filemap_invalidate_lock(inode->i_mapping);
/*
* unmap_mapping_range just need to be called once
* here, because the private pages is not need to be
* unmapped mapping (e.g. data segment of dynamic
* shared libraries here).
*/
unmap_mapping_range(mapping, 0, 0, 0);
truncate_inode_pages(mapping, 0);
filemap_invalidate_unlock(inode->i_mapping);
}
}
/*
* Once we return a file with FMODE_OPENED, __fput() will call
* fsnotify_close(), so we need fsnotify_open() here for symmetry.
*/
fsnotify_open(f);
return 0;
cleanup_all:
if (WARN_ON_ONCE(error > 0))
error = -EINVAL;
fops_put(f->f_op);
put_file_access(f);
cleanup_file:
path_put(&f->f_path);
f->f_path.mnt = NULL;
f->f_path.dentry = NULL;
f->f_inode = NULL;
return error;
}
/**
* finish_open - finish opening a file
* @file: file pointer
* @dentry: pointer to dentry
* @open: open callback
*
* This can be used to finish opening a file passed to i_op->atomic_open().
*
* If the open callback is set to NULL, then the standard f_op->open()
* filesystem callback is substituted.
*
* NB: the dentry reference is _not_ consumed. If, for example, the dentry is
* the return value of d_splice_alias(), then the caller needs to perform dput()
* on it after finish_open().
*
* Returns zero on success or -errno if the open failed.
*/
int finish_open(struct file *file, struct dentry *dentry,
int (*open)(struct inode *, struct file *))
{
BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */
file->f_path.dentry = dentry;
return do_dentry_open(file, d_backing_inode(dentry), open);
}
EXPORT_SYMBOL(finish_open);
/**
* finish_no_open - finish ->atomic_open() without opening the file
*
* @file: file pointer
* @dentry: dentry or NULL (as returned from ->lookup())
*
* This can be used to set the result of a successful lookup in ->atomic_open().
*
* NB: unlike finish_open() this function does consume the dentry reference and
* the caller need not dput() it.
*
* Returns "0" which must be the return value of ->atomic_open() after having
* called this function.
*/
int finish_no_open(struct file *file, struct dentry *dentry)
{
file->f_path.dentry = dentry;
return 0;
}
EXPORT_SYMBOL(finish_no_open);
char *file_path(struct file *filp, char *buf, int buflen)
{
return d_path(&filp->f_path, buf, buflen);
}
EXPORT_SYMBOL(file_path);
/**
* vfs_open - open the file at the given path
* @path: path to open
* @file: newly allocated file with f_flag initialized
*/
int vfs_open(const struct path *path, struct file *file)
{
file->f_path = *path;
return do_dentry_open(file, d_backing_inode(path->dentry), NULL);
}
struct file *dentry_open(const struct path *path, int flags,
const struct cred *cred)
{
int error;
struct file *f;
validate_creds(cred);
/* We must always pass in a valid mount pointer. */
BUG_ON(!path->mnt);
f = alloc_empty_file(flags, cred);
if (!IS_ERR(f)) {
error = vfs_open(path, f);
if (error) {
fput(f);
f = ERR_PTR(error);
}
}
return f;
}
EXPORT_SYMBOL(dentry_open);
/**
* dentry_create - Create and open a file
* @path: path to create
* @flags: O_ flags
* @mode: mode bits for new file
* @cred: credentials to use
*
* Caller must hold the parent directory's lock, and have prepared
* a negative dentry, placed in @path->dentry, for the new file.
*
* Caller sets @path->mnt to the vfsmount of the filesystem where
* the new file is to be created. The parent directory and the
* negative dentry must reside on the same filesystem instance.
*
* On success, returns a "struct file *". Otherwise a ERR_PTR
* is returned.
*/
struct file *dentry_create(const struct path *path, int flags, umode_t mode,
const struct cred *cred)
{
struct file *f;
int error;
validate_creds(cred);
f = alloc_empty_file(flags, cred);
if (IS_ERR(f))
return f;
error = vfs_create(mnt_idmap(path->mnt),
d_inode(path->dentry->d_parent),
path->dentry, mode, true);
if (!error)
error = vfs_open(path, f);
if (unlikely(error)) {
fput(f);
return ERR_PTR(error);
}
return f;
}
EXPORT_SYMBOL(dentry_create);
/**
* kernel_file_open - open a file for kernel internal use
* @path: path of the file to open
* @flags: open flags
* @inode: the inode
* @cred: credentials for open
*
* Open a file for use by in-kernel consumers. The file is not accounted
* against nr_files and must not be installed into the file descriptor
* table.
*
* Return: Opened file on success, an error pointer on failure.
*/
struct file *kernel_file_open(const struct path *path, int flags,
struct inode *inode, const struct cred *cred)
{
struct file *f;
int error;
f = alloc_empty_file_noaccount(flags, cred);
if (IS_ERR(f))
return f;
f->f_path = *path;
error = do_dentry_open(f, inode, NULL);
if (error) {
fput(f);
f = ERR_PTR(error);
}
return f;
}
EXPORT_SYMBOL_GPL(kernel_file_open);
/**
* backing_file_open - open a backing file for kernel internal use
* @path: path of the file to open
* @flags: open flags
* @real_path: path of the backing file
* @cred: credentials for open
*
* Open a backing file for a stackable filesystem (e.g., overlayfs).
* @path may be on the stackable filesystem and backing inode on the
* underlying filesystem. In this case, we want to be able to return
* the @real_path of the backing inode. This is done by embedding the
* returned file into a container structure that also stores the path of
* the backing inode on the underlying filesystem, which can be
* retrieved using backing_file_real_path().
*/
struct file *backing_file_open(const struct path *path, int flags,
const struct path *real_path,
const struct cred *cred)
{
struct file *f;
int error;
f = alloc_empty_backing_file(flags, cred);
if (IS_ERR(f))
return f;
f->f_path = *path;
path_get(real_path);
*backing_file_real_path(f) = *real_path;
error = do_dentry_open(f, d_inode(real_path->dentry), NULL);
if (error) {
fput(f);
f = ERR_PTR(error);
}
return f;
}
EXPORT_SYMBOL_GPL(backing_file_open);
#define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE))
#define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC)
inline struct open_how build_open_how(int flags, umode_t mode)
{
struct open_how how = {
.flags = flags & VALID_OPEN_FLAGS,
.mode = mode & S_IALLUGO,
};
/* O_PATH beats everything else. */
if (how.flags & O_PATH)
how.flags &= O_PATH_FLAGS;
/* Modes should only be set for create-like flags. */
if (!WILL_CREATE(how.flags))
how.mode = 0;
return how;
}
inline int build_open_flags(const struct open_how *how, struct open_flags *op)
{
u64 flags = how->flags;
u64 strip = __FMODE_NONOTIFY | O_CLOEXEC;
int lookup_flags = 0;
int acc_mode = ACC_MODE(flags);
BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS),
"struct open_flags doesn't yet handle flags > 32 bits");
/*
* Strip flags that either shouldn't be set by userspace like
* FMODE_NONOTIFY or that aren't relevant in determining struct
* open_flags like O_CLOEXEC.
*/
flags &= ~strip;
/*
* Older syscalls implicitly clear all of the invalid flags or argument
* values before calling build_open_flags(), but openat2(2) checks all
* of its arguments.
*/
if (flags & ~VALID_OPEN_FLAGS)
return -EINVAL;
if (how->resolve & ~VALID_RESOLVE_FLAGS)
return -EINVAL;
/* Scoping flags are mutually exclusive. */
if ((how->resolve & RESOLVE_BENEATH) && (how->resolve & RESOLVE_IN_ROOT))
return -EINVAL;
/* Deal with the mode. */
if (WILL_CREATE(flags)) {
if (how->mode & ~S_IALLUGO)
return -EINVAL;
op->mode = how->mode | S_IFREG;
} else {
if (how->mode != 0)
return -EINVAL;
op->mode = 0;
}
/*
* Block bugs where O_DIRECTORY | O_CREAT created regular files.
* Note, that blocking O_DIRECTORY | O_CREAT here also protects
* O_TMPFILE below which requires O_DIRECTORY being raised.
*/
if ((flags & (O_DIRECTORY | O_CREAT)) == (O_DIRECTORY | O_CREAT))
return -EINVAL;
/* Now handle the creative implementation of O_TMPFILE. */
if (flags & __O_TMPFILE) {
/*
* In order to ensure programs get explicit errors when trying
* to use O_TMPFILE on old kernels we enforce that O_DIRECTORY
* is raised alongside __O_TMPFILE.
*/
if (!(flags & O_DIRECTORY))
return -EINVAL;
if (!(acc_mode & MAY_WRITE))
return -EINVAL;
}
if (flags & O_PATH) {
/* O_PATH only permits certain other flags to be set. */
if (flags & ~O_PATH_FLAGS)
return -EINVAL;
acc_mode = 0;
}
/*
* O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
* check for O_DSYNC if the need any syncing at all we enforce it's
* always set instead of having to deal with possibly weird behaviour
* for malicious applications setting only __O_SYNC.
*/
if (flags & __O_SYNC)
flags |= O_DSYNC;
op->open_flag = flags;
/* O_TRUNC implies we need access checks for write permissions */
if (flags & O_TRUNC)
acc_mode |= MAY_WRITE;
/* Allow the LSM permission hook to distinguish append
access from general write access. */
if (flags & O_APPEND)
acc_mode |= MAY_APPEND;
op->acc_mode = acc_mode;
op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
if (flags & O_CREAT) {
op->intent |= LOOKUP_CREATE;
if (flags & O_EXCL) {
op->intent |= LOOKUP_EXCL;
flags |= O_NOFOLLOW;
}
}
if (flags & O_DIRECTORY)
lookup_flags |= LOOKUP_DIRECTORY;
if (!(flags & O_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
if (how->resolve & RESOLVE_NO_XDEV)
lookup_flags |= LOOKUP_NO_XDEV;
if (how->resolve & RESOLVE_NO_MAGICLINKS)
lookup_flags |= LOOKUP_NO_MAGICLINKS;
if (how->resolve & RESOLVE_NO_SYMLINKS)
lookup_flags |= LOOKUP_NO_SYMLINKS;
if (how->resolve & RESOLVE_BENEATH)
lookup_flags |= LOOKUP_BENEATH;
if (how->resolve & RESOLVE_IN_ROOT)
lookup_flags |= LOOKUP_IN_ROOT;
if (how->resolve & RESOLVE_CACHED) {
/* Don't bother even trying for create/truncate/tmpfile open */
if (flags & (O_TRUNC | O_CREAT | __O_TMPFILE))
return -EAGAIN;
lookup_flags |= LOOKUP_CACHED;
}
op->lookup_flags = lookup_flags;
return 0;
}
/**
* file_open_name - open file and return file pointer
*
* @name: struct filename containing path to open
* @flags: open flags as per the open(2) second argument
* @mode: mode for the new file if O_CREAT is set, else ignored
*
* This is the helper to open a file from kernelspace if you really
* have to. But in generally you should not do this, so please move
* along, nothing to see here..
*/
struct file *file_open_name(struct filename *name, int flags, umode_t mode)
{
struct open_flags op;
struct open_how how = build_open_how(flags, mode);
int err = build_open_flags(&how, &op);
if (err)
return ERR_PTR(err);
return do_filp_open(AT_FDCWD, name, &op);
}
/**
* filp_open - open file and return file pointer
*
* @filename: path to open
* @flags: open flags as per the open(2) second argument
* @mode: mode for the new file if O_CREAT is set, else ignored
*
* This is the helper to open a file from kernelspace if you really
* have to. But in generally you should not do this, so please move
* along, nothing to see here..
*/
struct file *filp_open(const char *filename, int flags, umode_t mode)
{
struct filename *name = getname_kernel(filename);
struct file *file = ERR_CAST(name);
if (!IS_ERR(name)) {
file = file_open_name(name, flags, mode);
putname(name);
}
return file;
}
EXPORT_SYMBOL(filp_open);
struct file *file_open_root(const struct path *root,
const char *filename, int flags, umode_t mode)
{
struct open_flags op;
struct open_how how = build_open_how(flags, mode);
int err = build_open_flags(&how, &op);
if (err)
return ERR_PTR(err);
return do_file_open_root(root, filename, &op);
}
EXPORT_SYMBOL(file_open_root);
static long do_sys_openat2(int dfd, const char __user *filename,
struct open_how *how)
{
struct open_flags op;
int fd = build_open_flags(how, &op);
struct filename *tmp;
if (fd)
return fd;
tmp = getname(filename);
if (IS_ERR(tmp))
return PTR_ERR(tmp);
fd = get_unused_fd_flags(how->flags);
if (fd >= 0) {
struct file *f = do_filp_open(dfd, tmp, &op);
if (IS_ERR(f)) {
put_unused_fd(fd);
fd = PTR_ERR(f);
} else {
fd_install(fd, f);
}
}
putname(tmp);
return fd;
}
long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
{
struct open_how how = build_open_how(flags, mode);
return do_sys_openat2(dfd, filename, &how);
}
SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
{
if (force_o_largefile())
flags |= O_LARGEFILE;
return do_sys_open(AT_FDCWD, filename, flags, mode);
}
SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
umode_t, mode)
{
if (force_o_largefile())
flags |= O_LARGEFILE;
return do_sys_open(dfd, filename, flags, mode);
}
SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename,
struct open_how __user *, how, size_t, usize)
{
int err;
struct open_how tmp;
BUILD_BUG_ON(sizeof(struct open_how) < OPEN_HOW_SIZE_VER0);
BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_LATEST);
if (unlikely(usize < OPEN_HOW_SIZE_VER0))
return -EINVAL;
err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize);
if (err)
return err;
audit_openat2_how(&tmp);
/* O_LARGEFILE is only allowed for non-O_PATH. */
if (!(tmp.flags & O_PATH) && force_o_largefile())
tmp.flags |= O_LARGEFILE;
return do_sys_openat2(dfd, filename, &tmp);
}
#ifdef CONFIG_COMPAT
/*
* Exactly like sys_open(), except that it doesn't set the
* O_LARGEFILE flag.
*/
COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
{
return do_sys_open(AT_FDCWD, filename, flags, mode);
}
/*
* Exactly like sys_openat(), except that it doesn't set the
* O_LARGEFILE flag.
*/
COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode)
{
return do_sys_open(dfd, filename, flags, mode);
}
#endif
#ifndef __alpha__
/*
* For backward compatibility? Maybe this should be moved
* into arch/i386 instead?
*/
SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
{
int flags = O_CREAT | O_WRONLY | O_TRUNC;
if (force_o_largefile())
flags |= O_LARGEFILE;
return do_sys_open(AT_FDCWD, pathname, flags, mode);
}
#endif
/*
* "id" is the POSIX thread ID. We use the
* files pointer for this..
*/
static int filp_flush(struct file *filp, fl_owner_t id)
{
int retval = 0;
if (CHECK_DATA_CORRUPTION(file_count(filp) == 0,
"VFS: Close: file count is 0 (f_op=%ps)",
filp->f_op)) {
return 0;
}
if (filp->f_op->flush)
retval = filp->f_op->flush(filp, id);
if (likely(!(filp->f_mode & FMODE_PATH))) {
dnotify_flush(filp, id);
locks_remove_posix(filp, id);
}
return retval;
}
int filp_close(struct file *filp, fl_owner_t id)
{
int retval;
retval = filp_flush(filp, id);
fput(filp);
return retval;
}
EXPORT_SYMBOL(filp_close);
/*
* Careful here! We test whether the file pointer is NULL before
* releasing the fd. This ensures that one clone task can't release
* an fd while another clone is opening it.
*/
SYSCALL_DEFINE1(close, unsigned int, fd)
{
int retval;
struct file *file;
file = close_fd_get_file(fd);
if (!file)
return -EBADF;
retval = filp_flush(file, current->files);
/*
* We're returning to user space. Don't bother
* with any delayed fput() cases.
*/
__fput_sync(file);
/* can't restart close syscall because file table entry was cleared */
if (unlikely(retval == -ERESTARTSYS ||
retval == -ERESTARTNOINTR ||
retval == -ERESTARTNOHAND ||
retval == -ERESTART_RESTARTBLOCK))
retval = -EINTR;
return retval;
}
/**
* sys_close_range() - Close all file descriptors in a given range.
*
* @fd: starting file descriptor to close
* @max_fd: last file descriptor to close
* @flags: reserved for future extensions
*
* This closes a range of file descriptors. All file descriptors
* from @fd up to and including @max_fd are closed.
* Currently, errors to close a given file descriptor are ignored.
*/
SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd,
unsigned int, flags)
{
return __close_range(fd, max_fd, flags);
}
/*
* This routine simulates a hangup on the tty, to arrange that users
* are given clean terminals at login time.
*/
SYSCALL_DEFINE0(vhangup)
{
if (capable(CAP_SYS_TTY_CONFIG)) {
tty_vhangup_self();
return 0;
}
return -EPERM;
}
/*
* Called when an inode is about to be open.
* We use this to disallow opening large files on 32bit systems if
* the caller didn't specify O_LARGEFILE. On 64bit systems we force
* on this flag in sys_open.
*/
int generic_file_open(struct inode * inode, struct file * filp)
{
if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
return -EOVERFLOW;
return 0;
}
EXPORT_SYMBOL(generic_file_open);
/*
* This is used by subsystems that don't want seekable
* file descriptors. The function is not supposed to ever fail, the only
* reason it returns an 'int' and not 'void' is so that it can be plugged
* directly into file_operations structure.
*/
int nonseekable_open(struct inode *inode, struct file *filp)
{
filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
return 0;
}
EXPORT_SYMBOL(nonseekable_open);
/*
* stream_open is used by subsystems that want stream-like file descriptors.
* Such file descriptors are not seekable and don't have notion of position
* (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
* Contrary to file descriptors of other regular files, .read() and .write()
* can run simultaneously.
*
* stream_open never fails and is marked to return int so that it could be
* directly used as file_operations.open .
*/
int stream_open(struct inode *inode, struct file *filp)
{
filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
filp->f_mode |= FMODE_STREAM;
return 0;
}
EXPORT_SYMBOL(stream_open);
| linux-master | fs/open.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/namespace.c
*
* (C) Copyright Al Viro 2000, 2001
*
* Based on code from fs/super.c, copyright Linus Torvalds and others.
* Heavily rewritten.
*/
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/capability.h>
#include <linux/mnt_namespace.h>
#include <linux/user_namespace.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/idr.h>
#include <linux/init.h> /* init_rootfs */
#include <linux/fs_struct.h> /* get_fs_root et.al. */
#include <linux/fsnotify.h> /* fsnotify_vfsmount_delete */
#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/proc_ns.h>
#include <linux/magic.h>
#include <linux/memblock.h>
#include <linux/proc_fs.h>
#include <linux/task_work.h>
#include <linux/sched/task.h>
#include <uapi/linux/mount.h>
#include <linux/fs_context.h>
#include <linux/shmem_fs.h>
#include <linux/mnt_idmapping.h>
#include "pnode.h"
#include "internal.h"
/* Maximum number of mounts in a mount namespace */
static unsigned int sysctl_mount_max __read_mostly = 100000;
static unsigned int m_hash_mask __read_mostly;
static unsigned int m_hash_shift __read_mostly;
static unsigned int mp_hash_mask __read_mostly;
static unsigned int mp_hash_shift __read_mostly;
static __initdata unsigned long mhash_entries;
static int __init set_mhash_entries(char *str)
{
if (!str)
return 0;
mhash_entries = simple_strtoul(str, &str, 0);
return 1;
}
__setup("mhash_entries=", set_mhash_entries);
static __initdata unsigned long mphash_entries;
static int __init set_mphash_entries(char *str)
{
if (!str)
return 0;
mphash_entries = simple_strtoul(str, &str, 0);
return 1;
}
__setup("mphash_entries=", set_mphash_entries);
static u64 event;
static DEFINE_IDA(mnt_id_ida);
static DEFINE_IDA(mnt_group_ida);
static struct hlist_head *mount_hashtable __read_mostly;
static struct hlist_head *mountpoint_hashtable __read_mostly;
static struct kmem_cache *mnt_cache __read_mostly;
static DECLARE_RWSEM(namespace_sem);
static HLIST_HEAD(unmounted); /* protected by namespace_sem */
static LIST_HEAD(ex_mountpoints); /* protected by namespace_sem */
struct mount_kattr {
unsigned int attr_set;
unsigned int attr_clr;
unsigned int propagation;
unsigned int lookup_flags;
bool recurse;
struct user_namespace *mnt_userns;
struct mnt_idmap *mnt_idmap;
};
/* /sys/fs */
struct kobject *fs_kobj;
EXPORT_SYMBOL_GPL(fs_kobj);
/*
* vfsmount lock may be taken for read to prevent changes to the
* vfsmount hash, ie. during mountpoint lookups or walking back
* up the tree.
*
* It should be taken for write in all cases where the vfsmount
* tree or hash is modified or when a vfsmount structure is modified.
*/
__cacheline_aligned_in_smp DEFINE_SEQLOCK(mount_lock);
static inline void lock_mount_hash(void)
{
write_seqlock(&mount_lock);
}
static inline void unlock_mount_hash(void)
{
write_sequnlock(&mount_lock);
}
static inline struct hlist_head *m_hash(struct vfsmount *mnt, struct dentry *dentry)
{
unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
tmp += ((unsigned long)dentry / L1_CACHE_BYTES);
tmp = tmp + (tmp >> m_hash_shift);
return &mount_hashtable[tmp & m_hash_mask];
}
static inline struct hlist_head *mp_hash(struct dentry *dentry)
{
unsigned long tmp = ((unsigned long)dentry / L1_CACHE_BYTES);
tmp = tmp + (tmp >> mp_hash_shift);
return &mountpoint_hashtable[tmp & mp_hash_mask];
}
static int mnt_alloc_id(struct mount *mnt)
{
int res = ida_alloc(&mnt_id_ida, GFP_KERNEL);
if (res < 0)
return res;
mnt->mnt_id = res;
return 0;
}
static void mnt_free_id(struct mount *mnt)
{
ida_free(&mnt_id_ida, mnt->mnt_id);
}
/*
* Allocate a new peer group ID
*/
static int mnt_alloc_group_id(struct mount *mnt)
{
int res = ida_alloc_min(&mnt_group_ida, 1, GFP_KERNEL);
if (res < 0)
return res;
mnt->mnt_group_id = res;
return 0;
}
/*
* Release a peer group ID
*/
void mnt_release_group_id(struct mount *mnt)
{
ida_free(&mnt_group_ida, mnt->mnt_group_id);
mnt->mnt_group_id = 0;
}
/*
* vfsmount lock must be held for read
*/
static inline void mnt_add_count(struct mount *mnt, int n)
{
#ifdef CONFIG_SMP
this_cpu_add(mnt->mnt_pcp->mnt_count, n);
#else
preempt_disable();
mnt->mnt_count += n;
preempt_enable();
#endif
}
/*
* vfsmount lock must be held for write
*/
int mnt_get_count(struct mount *mnt)
{
#ifdef CONFIG_SMP
int count = 0;
int cpu;
for_each_possible_cpu(cpu) {
count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_count;
}
return count;
#else
return mnt->mnt_count;
#endif
}
static struct mount *alloc_vfsmnt(const char *name)
{
struct mount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
if (mnt) {
int err;
err = mnt_alloc_id(mnt);
if (err)
goto out_free_cache;
if (name) {
mnt->mnt_devname = kstrdup_const(name,
GFP_KERNEL_ACCOUNT);
if (!mnt->mnt_devname)
goto out_free_id;
}
#ifdef CONFIG_SMP
mnt->mnt_pcp = alloc_percpu(struct mnt_pcp);
if (!mnt->mnt_pcp)
goto out_free_devname;
this_cpu_add(mnt->mnt_pcp->mnt_count, 1);
#else
mnt->mnt_count = 1;
mnt->mnt_writers = 0;
#endif
INIT_HLIST_NODE(&mnt->mnt_hash);
INIT_LIST_HEAD(&mnt->mnt_child);
INIT_LIST_HEAD(&mnt->mnt_mounts);
INIT_LIST_HEAD(&mnt->mnt_list);
INIT_LIST_HEAD(&mnt->mnt_expire);
INIT_LIST_HEAD(&mnt->mnt_share);
INIT_LIST_HEAD(&mnt->mnt_slave_list);
INIT_LIST_HEAD(&mnt->mnt_slave);
INIT_HLIST_NODE(&mnt->mnt_mp_list);
INIT_LIST_HEAD(&mnt->mnt_umounting);
INIT_HLIST_HEAD(&mnt->mnt_stuck_children);
mnt->mnt.mnt_idmap = &nop_mnt_idmap;
}
return mnt;
#ifdef CONFIG_SMP
out_free_devname:
kfree_const(mnt->mnt_devname);
#endif
out_free_id:
mnt_free_id(mnt);
out_free_cache:
kmem_cache_free(mnt_cache, mnt);
return NULL;
}
/*
* Most r/o checks on a fs are for operations that take
* discrete amounts of time, like a write() or unlink().
* We must keep track of when those operations start
* (for permission checks) and when they end, so that
* we can determine when writes are able to occur to
* a filesystem.
*/
/*
* __mnt_is_readonly: check whether a mount is read-only
* @mnt: the mount to check for its write status
*
* This shouldn't be used directly ouside of the VFS.
* It does not guarantee that the filesystem will stay
* r/w, just that it is right *now*. This can not and
* should not be used in place of IS_RDONLY(inode).
* mnt_want/drop_write() will _keep_ the filesystem
* r/w.
*/
bool __mnt_is_readonly(struct vfsmount *mnt)
{
return (mnt->mnt_flags & MNT_READONLY) || sb_rdonly(mnt->mnt_sb);
}
EXPORT_SYMBOL_GPL(__mnt_is_readonly);
static inline void mnt_inc_writers(struct mount *mnt)
{
#ifdef CONFIG_SMP
this_cpu_inc(mnt->mnt_pcp->mnt_writers);
#else
mnt->mnt_writers++;
#endif
}
static inline void mnt_dec_writers(struct mount *mnt)
{
#ifdef CONFIG_SMP
this_cpu_dec(mnt->mnt_pcp->mnt_writers);
#else
mnt->mnt_writers--;
#endif
}
static unsigned int mnt_get_writers(struct mount *mnt)
{
#ifdef CONFIG_SMP
unsigned int count = 0;
int cpu;
for_each_possible_cpu(cpu) {
count += per_cpu_ptr(mnt->mnt_pcp, cpu)->mnt_writers;
}
return count;
#else
return mnt->mnt_writers;
#endif
}
static int mnt_is_readonly(struct vfsmount *mnt)
{
if (READ_ONCE(mnt->mnt_sb->s_readonly_remount))
return 1;
/*
* The barrier pairs with the barrier in sb_start_ro_state_change()
* making sure if we don't see s_readonly_remount set yet, we also will
* not see any superblock / mount flag changes done by remount.
* It also pairs with the barrier in sb_end_ro_state_change()
* assuring that if we see s_readonly_remount already cleared, we will
* see the values of superblock / mount flags updated by remount.
*/
smp_rmb();
return __mnt_is_readonly(mnt);
}
/*
* Most r/o & frozen checks on a fs are for operations that take discrete
* amounts of time, like a write() or unlink(). We must keep track of when
* those operations start (for permission checks) and when they end, so that we
* can determine when writes are able to occur to a filesystem.
*/
/**
* __mnt_want_write - get write access to a mount without freeze protection
* @m: the mount on which to take a write
*
* This tells the low-level filesystem that a write is about to be performed to
* it, and makes sure that writes are allowed (mnt it read-write) before
* returning success. This operation does not protect against filesystem being
* frozen. When the write operation is finished, __mnt_drop_write() must be
* called. This is effectively a refcount.
*/
int __mnt_want_write(struct vfsmount *m)
{
struct mount *mnt = real_mount(m);
int ret = 0;
preempt_disable();
mnt_inc_writers(mnt);
/*
* The store to mnt_inc_writers must be visible before we pass
* MNT_WRITE_HOLD loop below, so that the slowpath can see our
* incremented count after it has set MNT_WRITE_HOLD.
*/
smp_mb();
might_lock(&mount_lock.lock);
while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) {
if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
cpu_relax();
} else {
/*
* This prevents priority inversion, if the task
* setting MNT_WRITE_HOLD got preempted on a remote
* CPU, and it prevents life lock if the task setting
* MNT_WRITE_HOLD has a lower priority and is bound to
* the same CPU as the task that is spinning here.
*/
preempt_enable();
lock_mount_hash();
unlock_mount_hash();
preempt_disable();
}
}
/*
* The barrier pairs with the barrier sb_start_ro_state_change() making
* sure that if we see MNT_WRITE_HOLD cleared, we will also see
* s_readonly_remount set (or even SB_RDONLY / MNT_READONLY flags) in
* mnt_is_readonly() and bail in case we are racing with remount
* read-only.
*/
smp_rmb();
if (mnt_is_readonly(m)) {
mnt_dec_writers(mnt);
ret = -EROFS;
}
preempt_enable();
return ret;
}
/**
* mnt_want_write - get write access to a mount
* @m: the mount on which to take a write
*
* This tells the low-level filesystem that a write is about to be performed to
* it, and makes sure that writes are allowed (mount is read-write, filesystem
* is not frozen) before returning success. When the write operation is
* finished, mnt_drop_write() must be called. This is effectively a refcount.
*/
int mnt_want_write(struct vfsmount *m)
{
int ret;
sb_start_write(m->mnt_sb);
ret = __mnt_want_write(m);
if (ret)
sb_end_write(m->mnt_sb);
return ret;
}
EXPORT_SYMBOL_GPL(mnt_want_write);
/**
* __mnt_want_write_file - get write access to a file's mount
* @file: the file who's mount on which to take a write
*
* This is like __mnt_want_write, but if the file is already open for writing it
* skips incrementing mnt_writers (since the open file already has a reference)
* and instead only does the check for emergency r/o remounts. This must be
* paired with __mnt_drop_write_file.
*/
int __mnt_want_write_file(struct file *file)
{
if (file->f_mode & FMODE_WRITER) {
/*
* Superblock may have become readonly while there are still
* writable fd's, e.g. due to a fs error with errors=remount-ro
*/
if (__mnt_is_readonly(file->f_path.mnt))
return -EROFS;
return 0;
}
return __mnt_want_write(file->f_path.mnt);
}
/**
* mnt_want_write_file - get write access to a file's mount
* @file: the file who's mount on which to take a write
*
* This is like mnt_want_write, but if the file is already open for writing it
* skips incrementing mnt_writers (since the open file already has a reference)
* and instead only does the freeze protection and the check for emergency r/o
* remounts. This must be paired with mnt_drop_write_file.
*/
int mnt_want_write_file(struct file *file)
{
int ret;
sb_start_write(file_inode(file)->i_sb);
ret = __mnt_want_write_file(file);
if (ret)
sb_end_write(file_inode(file)->i_sb);
return ret;
}
EXPORT_SYMBOL_GPL(mnt_want_write_file);
/**
* __mnt_drop_write - give up write access to a mount
* @mnt: the mount on which to give up write access
*
* Tells the low-level filesystem that we are done
* performing writes to it. Must be matched with
* __mnt_want_write() call above.
*/
void __mnt_drop_write(struct vfsmount *mnt)
{
preempt_disable();
mnt_dec_writers(real_mount(mnt));
preempt_enable();
}
/**
* mnt_drop_write - give up write access to a mount
* @mnt: the mount on which to give up write access
*
* Tells the low-level filesystem that we are done performing writes to it and
* also allows filesystem to be frozen again. Must be matched with
* mnt_want_write() call above.
*/
void mnt_drop_write(struct vfsmount *mnt)
{
__mnt_drop_write(mnt);
sb_end_write(mnt->mnt_sb);
}
EXPORT_SYMBOL_GPL(mnt_drop_write);
void __mnt_drop_write_file(struct file *file)
{
if (!(file->f_mode & FMODE_WRITER))
__mnt_drop_write(file->f_path.mnt);
}
void mnt_drop_write_file(struct file *file)
{
__mnt_drop_write_file(file);
sb_end_write(file_inode(file)->i_sb);
}
EXPORT_SYMBOL(mnt_drop_write_file);
/**
* mnt_hold_writers - prevent write access to the given mount
* @mnt: mnt to prevent write access to
*
* Prevents write access to @mnt if there are no active writers for @mnt.
* This function needs to be called and return successfully before changing
* properties of @mnt that need to remain stable for callers with write access
* to @mnt.
*
* After this functions has been called successfully callers must pair it with
* a call to mnt_unhold_writers() in order to stop preventing write access to
* @mnt.
*
* Context: This function expects lock_mount_hash() to be held serializing
* setting MNT_WRITE_HOLD.
* Return: On success 0 is returned.
* On error, -EBUSY is returned.
*/
static inline int mnt_hold_writers(struct mount *mnt)
{
mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;
/*
* After storing MNT_WRITE_HOLD, we'll read the counters. This store
* should be visible before we do.
*/
smp_mb();
/*
* With writers on hold, if this value is zero, then there are
* definitely no active writers (although held writers may subsequently
* increment the count, they'll have to wait, and decrement it after
* seeing MNT_READONLY).
*
* It is OK to have counter incremented on one CPU and decremented on
* another: the sum will add up correctly. The danger would be when we
* sum up each counter, if we read a counter before it is incremented,
* but then read another CPU's count which it has been subsequently
* decremented from -- we would see more decrements than we should.
* MNT_WRITE_HOLD protects against this scenario, because
* mnt_want_write first increments count, then smp_mb, then spins on
* MNT_WRITE_HOLD, so it can't be decremented by another CPU while
* we're counting up here.
*/
if (mnt_get_writers(mnt) > 0)
return -EBUSY;
return 0;
}
/**
* mnt_unhold_writers - stop preventing write access to the given mount
* @mnt: mnt to stop preventing write access to
*
* Stop preventing write access to @mnt allowing callers to gain write access
* to @mnt again.
*
* This function can only be called after a successful call to
* mnt_hold_writers().
*
* Context: This function expects lock_mount_hash() to be held.
*/
static inline void mnt_unhold_writers(struct mount *mnt)
{
/*
* MNT_READONLY must become visible before ~MNT_WRITE_HOLD, so writers
* that become unheld will see MNT_READONLY.
*/
smp_wmb();
mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;
}
static int mnt_make_readonly(struct mount *mnt)
{
int ret;
ret = mnt_hold_writers(mnt);
if (!ret)
mnt->mnt.mnt_flags |= MNT_READONLY;
mnt_unhold_writers(mnt);
return ret;
}
int sb_prepare_remount_readonly(struct super_block *sb)
{
struct mount *mnt;
int err = 0;
/* Racy optimization. Recheck the counter under MNT_WRITE_HOLD */
if (atomic_long_read(&sb->s_remove_count))
return -EBUSY;
lock_mount_hash();
list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) {
if (!(mnt->mnt.mnt_flags & MNT_READONLY)) {
err = mnt_hold_writers(mnt);
if (err)
break;
}
}
if (!err && atomic_long_read(&sb->s_remove_count))
err = -EBUSY;
if (!err)
sb_start_ro_state_change(sb);
list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) {
if (mnt->mnt.mnt_flags & MNT_WRITE_HOLD)
mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;
}
unlock_mount_hash();
return err;
}
static void free_vfsmnt(struct mount *mnt)
{
mnt_idmap_put(mnt_idmap(&mnt->mnt));
kfree_const(mnt->mnt_devname);
#ifdef CONFIG_SMP
free_percpu(mnt->mnt_pcp);
#endif
kmem_cache_free(mnt_cache, mnt);
}
static void delayed_free_vfsmnt(struct rcu_head *head)
{
free_vfsmnt(container_of(head, struct mount, mnt_rcu));
}
/* call under rcu_read_lock */
int __legitimize_mnt(struct vfsmount *bastard, unsigned seq)
{
struct mount *mnt;
if (read_seqretry(&mount_lock, seq))
return 1;
if (bastard == NULL)
return 0;
mnt = real_mount(bastard);
mnt_add_count(mnt, 1);
smp_mb(); // see mntput_no_expire()
if (likely(!read_seqretry(&mount_lock, seq)))
return 0;
if (bastard->mnt_flags & MNT_SYNC_UMOUNT) {
mnt_add_count(mnt, -1);
return 1;
}
lock_mount_hash();
if (unlikely(bastard->mnt_flags & MNT_DOOMED)) {
mnt_add_count(mnt, -1);
unlock_mount_hash();
return 1;
}
unlock_mount_hash();
/* caller will mntput() */
return -1;
}
/* call under rcu_read_lock */
static bool legitimize_mnt(struct vfsmount *bastard, unsigned seq)
{
int res = __legitimize_mnt(bastard, seq);
if (likely(!res))
return true;
if (unlikely(res < 0)) {
rcu_read_unlock();
mntput(bastard);
rcu_read_lock();
}
return false;
}
/**
* __lookup_mnt - find first child mount
* @mnt: parent mount
* @dentry: mountpoint
*
* If @mnt has a child mount @c mounted @dentry find and return it.
*
* Note that the child mount @c need not be unique. There are cases
* where shadow mounts are created. For example, during mount
* propagation when a source mount @mnt whose root got overmounted by a
* mount @o after path lookup but before @namespace_sem could be
* acquired gets copied and propagated. So @mnt gets copied including
* @o. When @mnt is propagated to a destination mount @d that already
* has another mount @n mounted at the same mountpoint then the source
* mount @mnt will be tucked beneath @n, i.e., @n will be mounted on
* @mnt and @mnt mounted on @d. Now both @n and @o are mounted at @mnt
* on @dentry.
*
* Return: The first child of @mnt mounted @dentry or NULL.
*/
struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
{
struct hlist_head *head = m_hash(mnt, dentry);
struct mount *p;
hlist_for_each_entry_rcu(p, head, mnt_hash)
if (&p->mnt_parent->mnt == mnt && p->mnt_mountpoint == dentry)
return p;
return NULL;
}
/*
* lookup_mnt - Return the first child mount mounted at path
*
* "First" means first mounted chronologically. If you create the
* following mounts:
*
* mount /dev/sda1 /mnt
* mount /dev/sda2 /mnt
* mount /dev/sda3 /mnt
*
* Then lookup_mnt() on the base /mnt dentry in the root mount will
* return successively the root dentry and vfsmount of /dev/sda1, then
* /dev/sda2, then /dev/sda3, then NULL.
*
* lookup_mnt takes a reference to the found vfsmount.
*/
struct vfsmount *lookup_mnt(const struct path *path)
{
struct mount *child_mnt;
struct vfsmount *m;
unsigned seq;
rcu_read_lock();
do {
seq = read_seqbegin(&mount_lock);
child_mnt = __lookup_mnt(path->mnt, path->dentry);
m = child_mnt ? &child_mnt->mnt : NULL;
} while (!legitimize_mnt(m, seq));
rcu_read_unlock();
return m;
}
static inline void lock_ns_list(struct mnt_namespace *ns)
{
spin_lock(&ns->ns_lock);
}
static inline void unlock_ns_list(struct mnt_namespace *ns)
{
spin_unlock(&ns->ns_lock);
}
static inline bool mnt_is_cursor(struct mount *mnt)
{
return mnt->mnt.mnt_flags & MNT_CURSOR;
}
/*
* __is_local_mountpoint - Test to see if dentry is a mountpoint in the
* current mount namespace.
*
* The common case is dentries are not mountpoints at all and that
* test is handled inline. For the slow case when we are actually
* dealing with a mountpoint of some kind, walk through all of the
* mounts in the current mount namespace and test to see if the dentry
* is a mountpoint.
*
* The mount_hashtable is not usable in the context because we
* need to identify all mounts that may be in the current mount
* namespace not just a mount that happens to have some specified
* parent mount.
*/
bool __is_local_mountpoint(struct dentry *dentry)
{
struct mnt_namespace *ns = current->nsproxy->mnt_ns;
struct mount *mnt;
bool is_covered = false;
down_read(&namespace_sem);
lock_ns_list(ns);
list_for_each_entry(mnt, &ns->list, mnt_list) {
if (mnt_is_cursor(mnt))
continue;
is_covered = (mnt->mnt_mountpoint == dentry);
if (is_covered)
break;
}
unlock_ns_list(ns);
up_read(&namespace_sem);
return is_covered;
}
static struct mountpoint *lookup_mountpoint(struct dentry *dentry)
{
struct hlist_head *chain = mp_hash(dentry);
struct mountpoint *mp;
hlist_for_each_entry(mp, chain, m_hash) {
if (mp->m_dentry == dentry) {
mp->m_count++;
return mp;
}
}
return NULL;
}
static struct mountpoint *get_mountpoint(struct dentry *dentry)
{
struct mountpoint *mp, *new = NULL;
int ret;
if (d_mountpoint(dentry)) {
/* might be worth a WARN_ON() */
if (d_unlinked(dentry))
return ERR_PTR(-ENOENT);
mountpoint:
read_seqlock_excl(&mount_lock);
mp = lookup_mountpoint(dentry);
read_sequnlock_excl(&mount_lock);
if (mp)
goto done;
}
if (!new)
new = kmalloc(sizeof(struct mountpoint), GFP_KERNEL);
if (!new)
return ERR_PTR(-ENOMEM);
/* Exactly one processes may set d_mounted */
ret = d_set_mounted(dentry);
/* Someone else set d_mounted? */
if (ret == -EBUSY)
goto mountpoint;
/* The dentry is not available as a mountpoint? */
mp = ERR_PTR(ret);
if (ret)
goto done;
/* Add the new mountpoint to the hash table */
read_seqlock_excl(&mount_lock);
new->m_dentry = dget(dentry);
new->m_count = 1;
hlist_add_head(&new->m_hash, mp_hash(dentry));
INIT_HLIST_HEAD(&new->m_list);
read_sequnlock_excl(&mount_lock);
mp = new;
new = NULL;
done:
kfree(new);
return mp;
}
/*
* vfsmount lock must be held. Additionally, the caller is responsible
* for serializing calls for given disposal list.
*/
static void __put_mountpoint(struct mountpoint *mp, struct list_head *list)
{
if (!--mp->m_count) {
struct dentry *dentry = mp->m_dentry;
BUG_ON(!hlist_empty(&mp->m_list));
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_MOUNTED;
spin_unlock(&dentry->d_lock);
dput_to_list(dentry, list);
hlist_del(&mp->m_hash);
kfree(mp);
}
}
/* called with namespace_lock and vfsmount lock */
static void put_mountpoint(struct mountpoint *mp)
{
__put_mountpoint(mp, &ex_mountpoints);
}
static inline int check_mnt(struct mount *mnt)
{
return mnt->mnt_ns == current->nsproxy->mnt_ns;
}
/*
* vfsmount lock must be held for write
*/
static void touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns) {
ns->event = ++event;
wake_up_interruptible(&ns->poll);
}
}
/*
* vfsmount lock must be held for write
*/
static void __touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns && ns->event != event) {
ns->event = event;
wake_up_interruptible(&ns->poll);
}
}
/*
* vfsmount lock must be held for write
*/
static struct mountpoint *unhash_mnt(struct mount *mnt)
{
struct mountpoint *mp;
mnt->mnt_parent = mnt;
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
list_del_init(&mnt->mnt_child);
hlist_del_init_rcu(&mnt->mnt_hash);
hlist_del_init(&mnt->mnt_mp_list);
mp = mnt->mnt_mp;
mnt->mnt_mp = NULL;
return mp;
}
/*
* vfsmount lock must be held for write
*/
static void umount_mnt(struct mount *mnt)
{
put_mountpoint(unhash_mnt(mnt));
}
/*
* vfsmount lock must be held for write
*/
void mnt_set_mountpoint(struct mount *mnt,
struct mountpoint *mp,
struct mount *child_mnt)
{
mp->m_count++;
mnt_add_count(mnt, 1); /* essentially, that's mntget */
child_mnt->mnt_mountpoint = mp->m_dentry;
child_mnt->mnt_parent = mnt;
child_mnt->mnt_mp = mp;
hlist_add_head(&child_mnt->mnt_mp_list, &mp->m_list);
}
/**
* mnt_set_mountpoint_beneath - mount a mount beneath another one
*
* @new_parent: the source mount
* @top_mnt: the mount beneath which @new_parent is mounted
* @new_mp: the new mountpoint of @top_mnt on @new_parent
*
* Remove @top_mnt from its current mountpoint @top_mnt->mnt_mp and
* parent @top_mnt->mnt_parent and mount it on top of @new_parent at
* @new_mp. And mount @new_parent on the old parent and old
* mountpoint of @top_mnt.
*
* Context: This function expects namespace_lock() and lock_mount_hash()
* to have been acquired in that order.
*/
static void mnt_set_mountpoint_beneath(struct mount *new_parent,
struct mount *top_mnt,
struct mountpoint *new_mp)
{
struct mount *old_top_parent = top_mnt->mnt_parent;
struct mountpoint *old_top_mp = top_mnt->mnt_mp;
mnt_set_mountpoint(old_top_parent, old_top_mp, new_parent);
mnt_change_mountpoint(new_parent, new_mp, top_mnt);
}
static void __attach_mnt(struct mount *mnt, struct mount *parent)
{
hlist_add_head_rcu(&mnt->mnt_hash,
m_hash(&parent->mnt, mnt->mnt_mountpoint));
list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);
}
/**
* attach_mnt - mount a mount, attach to @mount_hashtable and parent's
* list of child mounts
* @parent: the parent
* @mnt: the new mount
* @mp: the new mountpoint
* @beneath: whether to mount @mnt beneath or on top of @parent
*
* If @beneath is false, mount @mnt at @mp on @parent. Then attach @mnt
* to @parent's child mount list and to @mount_hashtable.
*
* If @beneath is true, remove @mnt from its current parent and
* mountpoint and mount it on @mp on @parent, and mount @parent on the
* old parent and old mountpoint of @mnt. Finally, attach @parent to
* @mnt_hashtable and @parent->mnt_parent->mnt_mounts.
*
* Note, when __attach_mnt() is called @mnt->mnt_parent already points
* to the correct parent.
*
* Context: This function expects namespace_lock() and lock_mount_hash()
* to have been acquired in that order.
*/
static void attach_mnt(struct mount *mnt, struct mount *parent,
struct mountpoint *mp, bool beneath)
{
if (beneath)
mnt_set_mountpoint_beneath(mnt, parent, mp);
else
mnt_set_mountpoint(parent, mp, mnt);
/*
* Note, @mnt->mnt_parent has to be used. If @mnt was mounted
* beneath @parent then @mnt will need to be attached to
* @parent's old parent, not @parent. IOW, @mnt->mnt_parent
* isn't the same mount as @parent.
*/
__attach_mnt(mnt, mnt->mnt_parent);
}
void mnt_change_mountpoint(struct mount *parent, struct mountpoint *mp, struct mount *mnt)
{
struct mountpoint *old_mp = mnt->mnt_mp;
struct mount *old_parent = mnt->mnt_parent;
list_del_init(&mnt->mnt_child);
hlist_del_init(&mnt->mnt_mp_list);
hlist_del_init_rcu(&mnt->mnt_hash);
attach_mnt(mnt, parent, mp, false);
put_mountpoint(old_mp);
mnt_add_count(old_parent, -1);
}
/*
* vfsmount lock must be held for write
*/
static void commit_tree(struct mount *mnt)
{
struct mount *parent = mnt->mnt_parent;
struct mount *m;
LIST_HEAD(head);
struct mnt_namespace *n = parent->mnt_ns;
BUG_ON(parent == mnt);
list_add_tail(&head, &mnt->mnt_list);
list_for_each_entry(m, &head, mnt_list)
m->mnt_ns = n;
list_splice(&head, n->list.prev);
n->mounts += n->pending_mounts;
n->pending_mounts = 0;
__attach_mnt(mnt, parent);
touch_mnt_namespace(n);
}
static struct mount *next_mnt(struct mount *p, struct mount *root)
{
struct list_head *next = p->mnt_mounts.next;
if (next == &p->mnt_mounts) {
while (1) {
if (p == root)
return NULL;
next = p->mnt_child.next;
if (next != &p->mnt_parent->mnt_mounts)
break;
p = p->mnt_parent;
}
}
return list_entry(next, struct mount, mnt_child);
}
static struct mount *skip_mnt_tree(struct mount *p)
{
struct list_head *prev = p->mnt_mounts.prev;
while (prev != &p->mnt_mounts) {
p = list_entry(prev, struct mount, mnt_child);
prev = p->mnt_mounts.prev;
}
return p;
}
/**
* vfs_create_mount - Create a mount for a configured superblock
* @fc: The configuration context with the superblock attached
*
* Create a mount to an already configured superblock. If necessary, the
* caller should invoke vfs_get_tree() before calling this.
*
* Note that this does not attach the mount to anything.
*/
struct vfsmount *vfs_create_mount(struct fs_context *fc)
{
struct mount *mnt;
if (!fc->root)
return ERR_PTR(-EINVAL);
mnt = alloc_vfsmnt(fc->source ?: "none");
if (!mnt)
return ERR_PTR(-ENOMEM);
if (fc->sb_flags & SB_KERNMOUNT)
mnt->mnt.mnt_flags = MNT_INTERNAL;
atomic_inc(&fc->root->d_sb->s_active);
mnt->mnt.mnt_sb = fc->root->d_sb;
mnt->mnt.mnt_root = dget(fc->root);
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = mnt;
lock_mount_hash();
list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts);
unlock_mount_hash();
return &mnt->mnt;
}
EXPORT_SYMBOL(vfs_create_mount);
struct vfsmount *fc_mount(struct fs_context *fc)
{
int err = vfs_get_tree(fc);
if (!err) {
up_write(&fc->root->d_sb->s_umount);
return vfs_create_mount(fc);
}
return ERR_PTR(err);
}
EXPORT_SYMBOL(fc_mount);
struct vfsmount *vfs_kern_mount(struct file_system_type *type,
int flags, const char *name,
void *data)
{
struct fs_context *fc;
struct vfsmount *mnt;
int ret = 0;
if (!type)
return ERR_PTR(-EINVAL);
fc = fs_context_for_mount(type, flags);
if (IS_ERR(fc))
return ERR_CAST(fc);
if (name)
ret = vfs_parse_fs_string(fc, "source",
name, strlen(name));
if (!ret)
ret = parse_monolithic_mount_data(fc, data);
if (!ret)
mnt = fc_mount(fc);
else
mnt = ERR_PTR(ret);
put_fs_context(fc);
return mnt;
}
EXPORT_SYMBOL_GPL(vfs_kern_mount);
struct vfsmount *
vfs_submount(const struct dentry *mountpoint, struct file_system_type *type,
const char *name, void *data)
{
/* Until it is worked out how to pass the user namespace
* through from the parent mount to the submount don't support
* unprivileged mounts with submounts.
*/
if (mountpoint->d_sb->s_user_ns != &init_user_ns)
return ERR_PTR(-EPERM);
return vfs_kern_mount(type, SB_SUBMOUNT, name, data);
}
EXPORT_SYMBOL_GPL(vfs_submount);
static struct mount *clone_mnt(struct mount *old, struct dentry *root,
int flag)
{
struct super_block *sb = old->mnt.mnt_sb;
struct mount *mnt;
int err;
mnt = alloc_vfsmnt(old->mnt_devname);
if (!mnt)
return ERR_PTR(-ENOMEM);
if (flag & (CL_SLAVE | CL_PRIVATE | CL_SHARED_TO_SLAVE))
mnt->mnt_group_id = 0; /* not a peer of original */
else
mnt->mnt_group_id = old->mnt_group_id;
if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) {
err = mnt_alloc_group_id(mnt);
if (err)
goto out_free;
}
mnt->mnt.mnt_flags = old->mnt.mnt_flags;
mnt->mnt.mnt_flags &= ~(MNT_WRITE_HOLD|MNT_MARKED|MNT_INTERNAL);
atomic_inc(&sb->s_active);
mnt->mnt.mnt_idmap = mnt_idmap_get(mnt_idmap(&old->mnt));
mnt->mnt.mnt_sb = sb;
mnt->mnt.mnt_root = dget(root);
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = mnt;
lock_mount_hash();
list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
unlock_mount_hash();
if ((flag & CL_SLAVE) ||
((flag & CL_SHARED_TO_SLAVE) && IS_MNT_SHARED(old))) {
list_add(&mnt->mnt_slave, &old->mnt_slave_list);
mnt->mnt_master = old;
CLEAR_MNT_SHARED(mnt);
} else if (!(flag & CL_PRIVATE)) {
if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old))
list_add(&mnt->mnt_share, &old->mnt_share);
if (IS_MNT_SLAVE(old))
list_add(&mnt->mnt_slave, &old->mnt_slave);
mnt->mnt_master = old->mnt_master;
} else {
CLEAR_MNT_SHARED(mnt);
}
if (flag & CL_MAKE_SHARED)
set_mnt_shared(mnt);
/* stick the duplicate mount on the same expiry list
* as the original if that was on one */
if (flag & CL_EXPIRE) {
if (!list_empty(&old->mnt_expire))
list_add(&mnt->mnt_expire, &old->mnt_expire);
}
return mnt;
out_free:
mnt_free_id(mnt);
free_vfsmnt(mnt);
return ERR_PTR(err);
}
static void cleanup_mnt(struct mount *mnt)
{
struct hlist_node *p;
struct mount *m;
/*
* The warning here probably indicates that somebody messed
* up a mnt_want/drop_write() pair. If this happens, the
* filesystem was probably unable to make r/w->r/o transitions.
* The locking used to deal with mnt_count decrement provides barriers,
* so mnt_get_writers() below is safe.
*/
WARN_ON(mnt_get_writers(mnt));
if (unlikely(mnt->mnt_pins.first))
mnt_pin_kill(mnt);
hlist_for_each_entry_safe(m, p, &mnt->mnt_stuck_children, mnt_umount) {
hlist_del(&m->mnt_umount);
mntput(&m->mnt);
}
fsnotify_vfsmount_delete(&mnt->mnt);
dput(mnt->mnt.mnt_root);
deactivate_super(mnt->mnt.mnt_sb);
mnt_free_id(mnt);
call_rcu(&mnt->mnt_rcu, delayed_free_vfsmnt);
}
static void __cleanup_mnt(struct rcu_head *head)
{
cleanup_mnt(container_of(head, struct mount, mnt_rcu));
}
static LLIST_HEAD(delayed_mntput_list);
static void delayed_mntput(struct work_struct *unused)
{
struct llist_node *node = llist_del_all(&delayed_mntput_list);
struct mount *m, *t;
llist_for_each_entry_safe(m, t, node, mnt_llist)
cleanup_mnt(m);
}
static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput);
static void mntput_no_expire(struct mount *mnt)
{
LIST_HEAD(list);
int count;
rcu_read_lock();
if (likely(READ_ONCE(mnt->mnt_ns))) {
/*
* Since we don't do lock_mount_hash() here,
* ->mnt_ns can change under us. However, if it's
* non-NULL, then there's a reference that won't
* be dropped until after an RCU delay done after
* turning ->mnt_ns NULL. So if we observe it
* non-NULL under rcu_read_lock(), the reference
* we are dropping is not the final one.
*/
mnt_add_count(mnt, -1);
rcu_read_unlock();
return;
}
lock_mount_hash();
/*
* make sure that if __legitimize_mnt() has not seen us grab
* mount_lock, we'll see their refcount increment here.
*/
smp_mb();
mnt_add_count(mnt, -1);
count = mnt_get_count(mnt);
if (count != 0) {
WARN_ON(count < 0);
rcu_read_unlock();
unlock_mount_hash();
return;
}
if (unlikely(mnt->mnt.mnt_flags & MNT_DOOMED)) {
rcu_read_unlock();
unlock_mount_hash();
return;
}
mnt->mnt.mnt_flags |= MNT_DOOMED;
rcu_read_unlock();
list_del(&mnt->mnt_instance);
if (unlikely(!list_empty(&mnt->mnt_mounts))) {
struct mount *p, *tmp;
list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts, mnt_child) {
__put_mountpoint(unhash_mnt(p), &list);
hlist_add_head(&p->mnt_umount, &mnt->mnt_stuck_children);
}
}
unlock_mount_hash();
shrink_dentry_list(&list);
if (likely(!(mnt->mnt.mnt_flags & MNT_INTERNAL))) {
struct task_struct *task = current;
if (likely(!(task->flags & PF_KTHREAD))) {
init_task_work(&mnt->mnt_rcu, __cleanup_mnt);
if (!task_work_add(task, &mnt->mnt_rcu, TWA_RESUME))
return;
}
if (llist_add(&mnt->mnt_llist, &delayed_mntput_list))
schedule_delayed_work(&delayed_mntput_work, 1);
return;
}
cleanup_mnt(mnt);
}
void mntput(struct vfsmount *mnt)
{
if (mnt) {
struct mount *m = real_mount(mnt);
/* avoid cacheline pingpong, hope gcc doesn't get "smart" */
if (unlikely(m->mnt_expiry_mark))
m->mnt_expiry_mark = 0;
mntput_no_expire(m);
}
}
EXPORT_SYMBOL(mntput);
struct vfsmount *mntget(struct vfsmount *mnt)
{
if (mnt)
mnt_add_count(real_mount(mnt), 1);
return mnt;
}
EXPORT_SYMBOL(mntget);
/*
* Make a mount point inaccessible to new lookups.
* Because there may still be current users, the caller MUST WAIT
* for an RCU grace period before destroying the mount point.
*/
void mnt_make_shortterm(struct vfsmount *mnt)
{
if (mnt)
real_mount(mnt)->mnt_ns = NULL;
}
/**
* path_is_mountpoint() - Check if path is a mount in the current namespace.
* @path: path to check
*
* d_mountpoint() can only be used reliably to establish if a dentry is
* not mounted in any namespace and that common case is handled inline.
* d_mountpoint() isn't aware of the possibility there may be multiple
* mounts using a given dentry in a different namespace. This function
* checks if the passed in path is a mountpoint rather than the dentry
* alone.
*/
bool path_is_mountpoint(const struct path *path)
{
unsigned seq;
bool res;
if (!d_mountpoint(path->dentry))
return false;
rcu_read_lock();
do {
seq = read_seqbegin(&mount_lock);
res = __path_is_mountpoint(path);
} while (read_seqretry(&mount_lock, seq));
rcu_read_unlock();
return res;
}
EXPORT_SYMBOL(path_is_mountpoint);
struct vfsmount *mnt_clone_internal(const struct path *path)
{
struct mount *p;
p = clone_mnt(real_mount(path->mnt), path->dentry, CL_PRIVATE);
if (IS_ERR(p))
return ERR_CAST(p);
p->mnt.mnt_flags |= MNT_INTERNAL;
return &p->mnt;
}
#ifdef CONFIG_PROC_FS
static struct mount *mnt_list_next(struct mnt_namespace *ns,
struct list_head *p)
{
struct mount *mnt, *ret = NULL;
lock_ns_list(ns);
list_for_each_continue(p, &ns->list) {
mnt = list_entry(p, typeof(*mnt), mnt_list);
if (!mnt_is_cursor(mnt)) {
ret = mnt;
break;
}
}
unlock_ns_list(ns);
return ret;
}
/* iterator; we want it to have access to namespace_sem, thus here... */
static void *m_start(struct seq_file *m, loff_t *pos)
{
struct proc_mounts *p = m->private;
struct list_head *prev;
down_read(&namespace_sem);
if (!*pos) {
prev = &p->ns->list;
} else {
prev = &p->cursor.mnt_list;
/* Read after we'd reached the end? */
if (list_empty(prev))
return NULL;
}
return mnt_list_next(p->ns, prev);
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
struct proc_mounts *p = m->private;
struct mount *mnt = v;
++*pos;
return mnt_list_next(p->ns, &mnt->mnt_list);
}
static void m_stop(struct seq_file *m, void *v)
{
struct proc_mounts *p = m->private;
struct mount *mnt = v;
lock_ns_list(p->ns);
if (mnt)
list_move_tail(&p->cursor.mnt_list, &mnt->mnt_list);
else
list_del_init(&p->cursor.mnt_list);
unlock_ns_list(p->ns);
up_read(&namespace_sem);
}
static int m_show(struct seq_file *m, void *v)
{
struct proc_mounts *p = m->private;
struct mount *r = v;
return p->show(m, &r->mnt);
}
const struct seq_operations mounts_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = m_show,
};
void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor)
{
down_read(&namespace_sem);
lock_ns_list(ns);
list_del(&cursor->mnt_list);
unlock_ns_list(ns);
up_read(&namespace_sem);
}
#endif /* CONFIG_PROC_FS */
/**
* may_umount_tree - check if a mount tree is busy
* @m: root of mount tree
*
* This is called to check if a tree of mounts has any
* open files, pwds, chroots or sub mounts that are
* busy.
*/
int may_umount_tree(struct vfsmount *m)
{
struct mount *mnt = real_mount(m);
int actual_refs = 0;
int minimum_refs = 0;
struct mount *p;
BUG_ON(!m);
/* write lock needed for mnt_get_count */
lock_mount_hash();
for (p = mnt; p; p = next_mnt(p, mnt)) {
actual_refs += mnt_get_count(p);
minimum_refs += 2;
}
unlock_mount_hash();
if (actual_refs > minimum_refs)
return 0;
return 1;
}
EXPORT_SYMBOL(may_umount_tree);
/**
* may_umount - check if a mount point is busy
* @mnt: root of mount
*
* This is called to check if a mount point has any
* open files, pwds, chroots or sub mounts. If the
* mount has sub mounts this will return busy
* regardless of whether the sub mounts are busy.
*
* Doesn't take quota and stuff into account. IOW, in some cases it will
* give false negatives. The main reason why it's here is that we need
* a non-destructive way to look for easily umountable filesystems.
*/
int may_umount(struct vfsmount *mnt)
{
int ret = 1;
down_read(&namespace_sem);
lock_mount_hash();
if (propagate_mount_busy(real_mount(mnt), 2))
ret = 0;
unlock_mount_hash();
up_read(&namespace_sem);
return ret;
}
EXPORT_SYMBOL(may_umount);
static void namespace_unlock(void)
{
struct hlist_head head;
struct hlist_node *p;
struct mount *m;
LIST_HEAD(list);
hlist_move_list(&unmounted, &head);
list_splice_init(&ex_mountpoints, &list);
up_write(&namespace_sem);
shrink_dentry_list(&list);
if (likely(hlist_empty(&head)))
return;
synchronize_rcu_expedited();
hlist_for_each_entry_safe(m, p, &head, mnt_umount) {
hlist_del(&m->mnt_umount);
mntput(&m->mnt);
}
}
static inline void namespace_lock(void)
{
down_write(&namespace_sem);
}
enum umount_tree_flags {
UMOUNT_SYNC = 1,
UMOUNT_PROPAGATE = 2,
UMOUNT_CONNECTED = 4,
};
static bool disconnect_mount(struct mount *mnt, enum umount_tree_flags how)
{
/* Leaving mounts connected is only valid for lazy umounts */
if (how & UMOUNT_SYNC)
return true;
/* A mount without a parent has nothing to be connected to */
if (!mnt_has_parent(mnt))
return true;
/* Because the reference counting rules change when mounts are
* unmounted and connected, umounted mounts may not be
* connected to mounted mounts.
*/
if (!(mnt->mnt_parent->mnt.mnt_flags & MNT_UMOUNT))
return true;
/* Has it been requested that the mount remain connected? */
if (how & UMOUNT_CONNECTED)
return false;
/* Is the mount locked such that it needs to remain connected? */
if (IS_MNT_LOCKED(mnt))
return false;
/* By default disconnect the mount */
return true;
}
/*
* mount_lock must be held
* namespace_sem must be held for write
*/
static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
{
LIST_HEAD(tmp_list);
struct mount *p;
if (how & UMOUNT_PROPAGATE)
propagate_mount_unlock(mnt);
/* Gather the mounts to umount */
for (p = mnt; p; p = next_mnt(p, mnt)) {
p->mnt.mnt_flags |= MNT_UMOUNT;
list_move(&p->mnt_list, &tmp_list);
}
/* Hide the mounts from mnt_mounts */
list_for_each_entry(p, &tmp_list, mnt_list) {
list_del_init(&p->mnt_child);
}
/* Add propogated mounts to the tmp_list */
if (how & UMOUNT_PROPAGATE)
propagate_umount(&tmp_list);
while (!list_empty(&tmp_list)) {
struct mnt_namespace *ns;
bool disconnect;
p = list_first_entry(&tmp_list, struct mount, mnt_list);
list_del_init(&p->mnt_expire);
list_del_init(&p->mnt_list);
ns = p->mnt_ns;
if (ns) {
ns->mounts--;
__touch_mnt_namespace(ns);
}
p->mnt_ns = NULL;
if (how & UMOUNT_SYNC)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
disconnect = disconnect_mount(p, how);
if (mnt_has_parent(p)) {
mnt_add_count(p->mnt_parent, -1);
if (!disconnect) {
/* Don't forget about p */
list_add_tail(&p->mnt_child, &p->mnt_parent->mnt_mounts);
} else {
umount_mnt(p);
}
}
change_mnt_propagation(p, MS_PRIVATE);
if (disconnect)
hlist_add_head(&p->mnt_umount, &unmounted);
}
}
static void shrink_submounts(struct mount *mnt);
static int do_umount_root(struct super_block *sb)
{
int ret = 0;
down_write(&sb->s_umount);
if (!sb_rdonly(sb)) {
struct fs_context *fc;
fc = fs_context_for_reconfigure(sb->s_root, SB_RDONLY,
SB_RDONLY);
if (IS_ERR(fc)) {
ret = PTR_ERR(fc);
} else {
ret = parse_monolithic_mount_data(fc, NULL);
if (!ret)
ret = reconfigure_super(fc);
put_fs_context(fc);
}
}
up_write(&sb->s_umount);
return ret;
}
static int do_umount(struct mount *mnt, int flags)
{
struct super_block *sb = mnt->mnt.mnt_sb;
int retval;
retval = security_sb_umount(&mnt->mnt, flags);
if (retval)
return retval;
/*
* Allow userspace to request a mountpoint be expired rather than
* unmounting unconditionally. Unmount only happens if:
* (1) the mark is already set (the mark is cleared by mntput())
* (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount]
*/
if (flags & MNT_EXPIRE) {
if (&mnt->mnt == current->fs->root.mnt ||
flags & (MNT_FORCE | MNT_DETACH))
return -EINVAL;
/*
* probably don't strictly need the lock here if we examined
* all race cases, but it's a slowpath.
*/
lock_mount_hash();
if (mnt_get_count(mnt) != 2) {
unlock_mount_hash();
return -EBUSY;
}
unlock_mount_hash();
if (!xchg(&mnt->mnt_expiry_mark, 1))
return -EAGAIN;
}
/*
* If we may have to abort operations to get out of this
* mount, and they will themselves hold resources we must
* allow the fs to do things. In the Unix tradition of
* 'Gee thats tricky lets do it in userspace' the umount_begin
* might fail to complete on the first run through as other tasks
* must return, and the like. Thats for the mount program to worry
* about for the moment.
*/
if (flags & MNT_FORCE && sb->s_op->umount_begin) {
sb->s_op->umount_begin(sb);
}
/*
* No sense to grab the lock for this test, but test itself looks
* somewhat bogus. Suggestions for better replacement?
* Ho-hum... In principle, we might treat that as umount + switch
* to rootfs. GC would eventually take care of the old vfsmount.
* Actually it makes sense, especially if rootfs would contain a
* /reboot - static binary that would close all descriptors and
* call reboot(9). Then init(8) could umount root and exec /reboot.
*/
if (&mnt->mnt == current->fs->root.mnt && !(flags & MNT_DETACH)) {
/*
* Special case for "unmounting" root ...
* we just try to remount it readonly.
*/
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;
return do_umount_root(sb);
}
namespace_lock();
lock_mount_hash();
/* Recheck MNT_LOCKED with the locks held */
retval = -EINVAL;
if (mnt->mnt.mnt_flags & MNT_LOCKED)
goto out;
event++;
if (flags & MNT_DETACH) {
if (!list_empty(&mnt->mnt_list))
umount_tree(mnt, UMOUNT_PROPAGATE);
retval = 0;
} else {
shrink_submounts(mnt);
retval = -EBUSY;
if (!propagate_mount_busy(mnt, 2)) {
if (!list_empty(&mnt->mnt_list))
umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
retval = 0;
}
}
out:
unlock_mount_hash();
namespace_unlock();
return retval;
}
/*
* __detach_mounts - lazily unmount all mounts on the specified dentry
*
* During unlink, rmdir, and d_drop it is possible to loose the path
* to an existing mountpoint, and wind up leaking the mount.
* detach_mounts allows lazily unmounting those mounts instead of
* leaking them.
*
* The caller may hold dentry->d_inode->i_mutex.
*/
void __detach_mounts(struct dentry *dentry)
{
struct mountpoint *mp;
struct mount *mnt;
namespace_lock();
lock_mount_hash();
mp = lookup_mountpoint(dentry);
if (!mp)
goto out_unlock;
event++;
while (!hlist_empty(&mp->m_list)) {
mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
umount_mnt(mnt);
hlist_add_head(&mnt->mnt_umount, &unmounted);
}
else umount_tree(mnt, UMOUNT_CONNECTED);
}
put_mountpoint(mp);
out_unlock:
unlock_mount_hash();
namespace_unlock();
}
/*
* Is the caller allowed to modify his namespace?
*/
bool may_mount(void)
{
return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN);
}
/**
* path_mounted - check whether path is mounted
* @path: path to check
*
* Determine whether @path refers to the root of a mount.
*
* Return: true if @path is the root of a mount, false if not.
*/
static inline bool path_mounted(const struct path *path)
{
return path->mnt->mnt_root == path->dentry;
}
static void warn_mandlock(void)
{
pr_warn_once("=======================================================\n"
"WARNING: The mand mount option has been deprecated and\n"
" and is ignored by this kernel. Remove the mand\n"
" option from the mount to silence this warning.\n"
"=======================================================\n");
}
static int can_umount(const struct path *path, int flags)
{
struct mount *mnt = real_mount(path->mnt);
if (!may_mount())
return -EPERM;
if (!path_mounted(path))
return -EINVAL;
if (!check_mnt(mnt))
return -EINVAL;
if (mnt->mnt.mnt_flags & MNT_LOCKED) /* Check optimistically */
return -EINVAL;
if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))
return -EPERM;
return 0;
}
// caller is responsible for flags being sane
int path_umount(struct path *path, int flags)
{
struct mount *mnt = real_mount(path->mnt);
int ret;
ret = can_umount(path, flags);
if (!ret)
ret = do_umount(mnt, flags);
/* we mustn't call path_put() as that would clear mnt_expiry_mark */
dput(path->dentry);
mntput_no_expire(mnt);
return ret;
}
static int ksys_umount(char __user *name, int flags)
{
int lookup_flags = LOOKUP_MOUNTPOINT;
struct path path;
int ret;
// basic validity checks done first
if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
return -EINVAL;
if (!(flags & UMOUNT_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
ret = user_path_at(AT_FDCWD, name, lookup_flags, &path);
if (ret)
return ret;
return path_umount(&path, flags);
}
SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
{
return ksys_umount(name, flags);
}
#ifdef __ARCH_WANT_SYS_OLDUMOUNT
/*
* The 2.0 compatible umount. No flags.
*/
SYSCALL_DEFINE1(oldumount, char __user *, name)
{
return ksys_umount(name, 0);
}
#endif
static bool is_mnt_ns_file(struct dentry *dentry)
{
/* Is this a proxy for a mount namespace? */
return dentry->d_op == &ns_dentry_operations &&
dentry->d_fsdata == &mntns_operations;
}
static struct mnt_namespace *to_mnt_ns(struct ns_common *ns)
{
return container_of(ns, struct mnt_namespace, ns);
}
struct ns_common *from_mnt_ns(struct mnt_namespace *mnt)
{
return &mnt->ns;
}
static bool mnt_ns_loop(struct dentry *dentry)
{
/* Could bind mounting the mount namespace inode cause a
* mount namespace loop?
*/
struct mnt_namespace *mnt_ns;
if (!is_mnt_ns_file(dentry))
return false;
mnt_ns = to_mnt_ns(get_proc_ns(dentry->d_inode));
return current->nsproxy->mnt_ns->seq >= mnt_ns->seq;
}
struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
int flag)
{
struct mount *res, *p, *q, *r, *parent;
if (!(flag & CL_COPY_UNBINDABLE) && IS_MNT_UNBINDABLE(mnt))
return ERR_PTR(-EINVAL);
if (!(flag & CL_COPY_MNT_NS_FILE) && is_mnt_ns_file(dentry))
return ERR_PTR(-EINVAL);
res = q = clone_mnt(mnt, dentry, flag);
if (IS_ERR(q))
return q;
q->mnt_mountpoint = mnt->mnt_mountpoint;
p = mnt;
list_for_each_entry(r, &mnt->mnt_mounts, mnt_child) {
struct mount *s;
if (!is_subdir(r->mnt_mountpoint, dentry))
continue;
for (s = r; s; s = next_mnt(s, r)) {
if (!(flag & CL_COPY_UNBINDABLE) &&
IS_MNT_UNBINDABLE(s)) {
if (s->mnt.mnt_flags & MNT_LOCKED) {
/* Both unbindable and locked. */
q = ERR_PTR(-EPERM);
goto out;
} else {
s = skip_mnt_tree(s);
continue;
}
}
if (!(flag & CL_COPY_MNT_NS_FILE) &&
is_mnt_ns_file(s->mnt.mnt_root)) {
s = skip_mnt_tree(s);
continue;
}
while (p != s->mnt_parent) {
p = p->mnt_parent;
q = q->mnt_parent;
}
p = s;
parent = q;
q = clone_mnt(p, p->mnt.mnt_root, flag);
if (IS_ERR(q))
goto out;
lock_mount_hash();
list_add_tail(&q->mnt_list, &res->mnt_list);
attach_mnt(q, parent, p->mnt_mp, false);
unlock_mount_hash();
}
}
return res;
out:
if (res) {
lock_mount_hash();
umount_tree(res, UMOUNT_SYNC);
unlock_mount_hash();
}
return q;
}
/* Caller should check returned pointer for errors */
struct vfsmount *collect_mounts(const struct path *path)
{
struct mount *tree;
namespace_lock();
if (!check_mnt(real_mount(path->mnt)))
tree = ERR_PTR(-EINVAL);
else
tree = copy_tree(real_mount(path->mnt), path->dentry,
CL_COPY_ALL | CL_PRIVATE);
namespace_unlock();
if (IS_ERR(tree))
return ERR_CAST(tree);
return &tree->mnt;
}
static void free_mnt_ns(struct mnt_namespace *);
static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *, bool);
void dissolve_on_fput(struct vfsmount *mnt)
{
struct mnt_namespace *ns;
namespace_lock();
lock_mount_hash();
ns = real_mount(mnt)->mnt_ns;
if (ns) {
if (is_anon_ns(ns))
umount_tree(real_mount(mnt), UMOUNT_CONNECTED);
else
ns = NULL;
}
unlock_mount_hash();
namespace_unlock();
if (ns)
free_mnt_ns(ns);
}
void drop_collected_mounts(struct vfsmount *mnt)
{
namespace_lock();
lock_mount_hash();
umount_tree(real_mount(mnt), 0);
unlock_mount_hash();
namespace_unlock();
}
static bool has_locked_children(struct mount *mnt, struct dentry *dentry)
{
struct mount *child;
list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
if (!is_subdir(child->mnt_mountpoint, dentry))
continue;
if (child->mnt.mnt_flags & MNT_LOCKED)
return true;
}
return false;
}
/**
* clone_private_mount - create a private clone of a path
* @path: path to clone
*
* This creates a new vfsmount, which will be the clone of @path. The new mount
* will not be attached anywhere in the namespace and will be private (i.e.
* changes to the originating mount won't be propagated into this).
*
* Release with mntput().
*/
struct vfsmount *clone_private_mount(const struct path *path)
{
struct mount *old_mnt = real_mount(path->mnt);
struct mount *new_mnt;
down_read(&namespace_sem);
if (IS_MNT_UNBINDABLE(old_mnt))
goto invalid;
if (!check_mnt(old_mnt))
goto invalid;
if (has_locked_children(old_mnt, path->dentry))
goto invalid;
new_mnt = clone_mnt(old_mnt, path->dentry, CL_PRIVATE);
up_read(&namespace_sem);
if (IS_ERR(new_mnt))
return ERR_CAST(new_mnt);
/* Longterm mount to be removed by kern_unmount*() */
new_mnt->mnt_ns = MNT_NS_INTERNAL;
return &new_mnt->mnt;
invalid:
up_read(&namespace_sem);
return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL_GPL(clone_private_mount);
int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
struct vfsmount *root)
{
struct mount *mnt;
int res = f(root, arg);
if (res)
return res;
list_for_each_entry(mnt, &real_mount(root)->mnt_list, mnt_list) {
res = f(&mnt->mnt, arg);
if (res)
return res;
}
return 0;
}
static void lock_mnt_tree(struct mount *mnt)
{
struct mount *p;
for (p = mnt; p; p = next_mnt(p, mnt)) {
int flags = p->mnt.mnt_flags;
/* Don't allow unprivileged users to change mount flags */
flags |= MNT_LOCK_ATIME;
if (flags & MNT_READONLY)
flags |= MNT_LOCK_READONLY;
if (flags & MNT_NODEV)
flags |= MNT_LOCK_NODEV;
if (flags & MNT_NOSUID)
flags |= MNT_LOCK_NOSUID;
if (flags & MNT_NOEXEC)
flags |= MNT_LOCK_NOEXEC;
/* Don't allow unprivileged users to reveal what is under a mount */
if (list_empty(&p->mnt_expire))
flags |= MNT_LOCKED;
p->mnt.mnt_flags = flags;
}
}
static void cleanup_group_ids(struct mount *mnt, struct mount *end)
{
struct mount *p;
for (p = mnt; p != end; p = next_mnt(p, mnt)) {
if (p->mnt_group_id && !IS_MNT_SHARED(p))
mnt_release_group_id(p);
}
}
static int invent_group_ids(struct mount *mnt, bool recurse)
{
struct mount *p;
for (p = mnt; p; p = recurse ? next_mnt(p, mnt) : NULL) {
if (!p->mnt_group_id && !IS_MNT_SHARED(p)) {
int err = mnt_alloc_group_id(p);
if (err) {
cleanup_group_ids(mnt, p);
return err;
}
}
}
return 0;
}
int count_mounts(struct mnt_namespace *ns, struct mount *mnt)
{
unsigned int max = READ_ONCE(sysctl_mount_max);
unsigned int mounts = 0;
struct mount *p;
if (ns->mounts >= max)
return -ENOSPC;
max -= ns->mounts;
if (ns->pending_mounts >= max)
return -ENOSPC;
max -= ns->pending_mounts;
for (p = mnt; p; p = next_mnt(p, mnt))
mounts++;
if (mounts > max)
return -ENOSPC;
ns->pending_mounts += mounts;
return 0;
}
enum mnt_tree_flags_t {
MNT_TREE_MOVE = BIT(0),
MNT_TREE_BENEATH = BIT(1),
};
/**
* attach_recursive_mnt - attach a source mount tree
* @source_mnt: mount tree to be attached
* @top_mnt: mount that @source_mnt will be mounted on or mounted beneath
* @dest_mp: the mountpoint @source_mnt will be mounted at
* @flags: modify how @source_mnt is supposed to be attached
*
* NOTE: in the table below explains the semantics when a source mount
* of a given type is attached to a destination mount of a given type.
* ---------------------------------------------------------------------------
* | BIND MOUNT OPERATION |
* |**************************************************************************
* | source-->| shared | private | slave | unbindable |
* | dest | | | | |
* | | | | | | |
* | v | | | | |
* |**************************************************************************
* | shared | shared (++) | shared (+) | shared(+++)| invalid |
* | | | | | |
* |non-shared| shared (+) | private | slave (*) | invalid |
* ***************************************************************************
* A bind operation clones the source mount and mounts the clone on the
* destination mount.
*
* (++) the cloned mount is propagated to all the mounts in the propagation
* tree of the destination mount and the cloned mount is added to
* the peer group of the source mount.
* (+) the cloned mount is created under the destination mount and is marked
* as shared. The cloned mount is added to the peer group of the source
* mount.
* (+++) the mount is propagated to all the mounts in the propagation tree
* of the destination mount and the cloned mount is made slave
* of the same master as that of the source mount. The cloned mount
* is marked as 'shared and slave'.
* (*) the cloned mount is made a slave of the same master as that of the
* source mount.
*
* ---------------------------------------------------------------------------
* | MOVE MOUNT OPERATION |
* |**************************************************************************
* | source-->| shared | private | slave | unbindable |
* | dest | | | | |
* | | | | | | |
* | v | | | | |
* |**************************************************************************
* | shared | shared (+) | shared (+) | shared(+++) | invalid |
* | | | | | |
* |non-shared| shared (+*) | private | slave (*) | unbindable |
* ***************************************************************************
*
* (+) the mount is moved to the destination. And is then propagated to
* all the mounts in the propagation tree of the destination mount.
* (+*) the mount is moved to the destination.
* (+++) the mount is moved to the destination and is then propagated to
* all the mounts belonging to the destination mount's propagation tree.
* the mount is marked as 'shared and slave'.
* (*) the mount continues to be a slave at the new location.
*
* if the source mount is a tree, the operations explained above is
* applied to each mount in the tree.
* Must be called without spinlocks held, since this function can sleep
* in allocations.
*
* Context: The function expects namespace_lock() to be held.
* Return: If @source_mnt was successfully attached 0 is returned.
* Otherwise a negative error code is returned.
*/
static int attach_recursive_mnt(struct mount *source_mnt,
struct mount *top_mnt,
struct mountpoint *dest_mp,
enum mnt_tree_flags_t flags)
{
struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns;
HLIST_HEAD(tree_list);
struct mnt_namespace *ns = top_mnt->mnt_ns;
struct mountpoint *smp;
struct mount *child, *dest_mnt, *p;
struct hlist_node *n;
int err = 0;
bool moving = flags & MNT_TREE_MOVE, beneath = flags & MNT_TREE_BENEATH;
/*
* Preallocate a mountpoint in case the new mounts need to be
* mounted beneath mounts on the same mountpoint.
*/
smp = get_mountpoint(source_mnt->mnt.mnt_root);
if (IS_ERR(smp))
return PTR_ERR(smp);
/* Is there space to add these mounts to the mount namespace? */
if (!moving) {
err = count_mounts(ns, source_mnt);
if (err)
goto out;
}
if (beneath)
dest_mnt = top_mnt->mnt_parent;
else
dest_mnt = top_mnt;
if (IS_MNT_SHARED(dest_mnt)) {
err = invent_group_ids(source_mnt, true);
if (err)
goto out;
err = propagate_mnt(dest_mnt, dest_mp, source_mnt, &tree_list);
}
lock_mount_hash();
if (err)
goto out_cleanup_ids;
if (IS_MNT_SHARED(dest_mnt)) {
for (p = source_mnt; p; p = next_mnt(p, source_mnt))
set_mnt_shared(p);
}
if (moving) {
if (beneath)
dest_mp = smp;
unhash_mnt(source_mnt);
attach_mnt(source_mnt, top_mnt, dest_mp, beneath);
touch_mnt_namespace(source_mnt->mnt_ns);
} else {
if (source_mnt->mnt_ns) {
/* move from anon - the caller will destroy */
list_del_init(&source_mnt->mnt_ns->list);
}
if (beneath)
mnt_set_mountpoint_beneath(source_mnt, top_mnt, smp);
else
mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt);
commit_tree(source_mnt);
}
hlist_for_each_entry_safe(child, n, &tree_list, mnt_hash) {
struct mount *q;
hlist_del_init(&child->mnt_hash);
q = __lookup_mnt(&child->mnt_parent->mnt,
child->mnt_mountpoint);
if (q)
mnt_change_mountpoint(child, smp, q);
/* Notice when we are propagating across user namespaces */
if (child->mnt_parent->mnt_ns->user_ns != user_ns)
lock_mnt_tree(child);
child->mnt.mnt_flags &= ~MNT_LOCKED;
commit_tree(child);
}
put_mountpoint(smp);
unlock_mount_hash();
return 0;
out_cleanup_ids:
while (!hlist_empty(&tree_list)) {
child = hlist_entry(tree_list.first, struct mount, mnt_hash);
child->mnt_parent->mnt_ns->pending_mounts = 0;
umount_tree(child, UMOUNT_SYNC);
}
unlock_mount_hash();
cleanup_group_ids(source_mnt, NULL);
out:
ns->pending_mounts = 0;
read_seqlock_excl(&mount_lock);
put_mountpoint(smp);
read_sequnlock_excl(&mount_lock);
return err;
}
/**
* do_lock_mount - lock mount and mountpoint
* @path: target path
* @beneath: whether the intention is to mount beneath @path
*
* Follow the mount stack on @path until the top mount @mnt is found. If
* the initial @path->{mnt,dentry} is a mountpoint lookup the first
* mount stacked on top of it. Then simply follow @{mnt,mnt->mnt_root}
* until nothing is stacked on top of it anymore.
*
* Acquire the inode_lock() on the top mount's ->mnt_root to protect
* against concurrent removal of the new mountpoint from another mount
* namespace.
*
* If @beneath is requested, acquire inode_lock() on @mnt's mountpoint
* @mp on @mnt->mnt_parent must be acquired. This protects against a
* concurrent unlink of @mp->mnt_dentry from another mount namespace
* where @mnt doesn't have a child mount mounted @mp. A concurrent
* removal of @mnt->mnt_root doesn't matter as nothing will be mounted
* on top of it for @beneath.
*
* In addition, @beneath needs to make sure that @mnt hasn't been
* unmounted or moved from its current mountpoint in between dropping
* @mount_lock and acquiring @namespace_sem. For the !@beneath case @mnt
* being unmounted would be detected later by e.g., calling
* check_mnt(mnt) in the function it's called from. For the @beneath
* case however, it's useful to detect it directly in do_lock_mount().
* If @mnt hasn't been unmounted then @mnt->mnt_mountpoint still points
* to @mnt->mnt_mp->m_dentry. But if @mnt has been unmounted it will
* point to @mnt->mnt_root and @mnt->mnt_mp will be NULL.
*
* Return: Either the target mountpoint on the top mount or the top
* mount's mountpoint.
*/
static struct mountpoint *do_lock_mount(struct path *path, bool beneath)
{
struct vfsmount *mnt = path->mnt;
struct dentry *dentry;
struct mountpoint *mp = ERR_PTR(-ENOENT);
for (;;) {
struct mount *m;
if (beneath) {
m = real_mount(mnt);
read_seqlock_excl(&mount_lock);
dentry = dget(m->mnt_mountpoint);
read_sequnlock_excl(&mount_lock);
} else {
dentry = path->dentry;
}
inode_lock(dentry->d_inode);
if (unlikely(cant_mount(dentry))) {
inode_unlock(dentry->d_inode);
goto out;
}
namespace_lock();
if (beneath && (!is_mounted(mnt) || m->mnt_mountpoint != dentry)) {
namespace_unlock();
inode_unlock(dentry->d_inode);
goto out;
}
mnt = lookup_mnt(path);
if (likely(!mnt))
break;
namespace_unlock();
inode_unlock(dentry->d_inode);
if (beneath)
dput(dentry);
path_put(path);
path->mnt = mnt;
path->dentry = dget(mnt->mnt_root);
}
mp = get_mountpoint(dentry);
if (IS_ERR(mp)) {
namespace_unlock();
inode_unlock(dentry->d_inode);
}
out:
if (beneath)
dput(dentry);
return mp;
}
static inline struct mountpoint *lock_mount(struct path *path)
{
return do_lock_mount(path, false);
}
static void unlock_mount(struct mountpoint *where)
{
struct dentry *dentry = where->m_dentry;
read_seqlock_excl(&mount_lock);
put_mountpoint(where);
read_sequnlock_excl(&mount_lock);
namespace_unlock();
inode_unlock(dentry->d_inode);
}
static int graft_tree(struct mount *mnt, struct mount *p, struct mountpoint *mp)
{
if (mnt->mnt.mnt_sb->s_flags & SB_NOUSER)
return -EINVAL;
if (d_is_dir(mp->m_dentry) !=
d_is_dir(mnt->mnt.mnt_root))
return -ENOTDIR;
return attach_recursive_mnt(mnt, p, mp, 0);
}
/*
* Sanity check the flags to change_mnt_propagation.
*/
static int flags_to_propagation_type(int ms_flags)
{
int type = ms_flags & ~(MS_REC | MS_SILENT);
/* Fail if any non-propagation flags are set */
if (type & ~(MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
return 0;
/* Only one propagation flag should be set */
if (!is_power_of_2(type))
return 0;
return type;
}
/*
* recursively change the type of the mountpoint.
*/
static int do_change_type(struct path *path, int ms_flags)
{
struct mount *m;
struct mount *mnt = real_mount(path->mnt);
int recurse = ms_flags & MS_REC;
int type;
int err = 0;
if (!path_mounted(path))
return -EINVAL;
type = flags_to_propagation_type(ms_flags);
if (!type)
return -EINVAL;
namespace_lock();
if (type == MS_SHARED) {
err = invent_group_ids(mnt, recurse);
if (err)
goto out_unlock;
}
lock_mount_hash();
for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
change_mnt_propagation(m, type);
unlock_mount_hash();
out_unlock:
namespace_unlock();
return err;
}
static struct mount *__do_loopback(struct path *old_path, int recurse)
{
struct mount *mnt = ERR_PTR(-EINVAL), *old = real_mount(old_path->mnt);
if (IS_MNT_UNBINDABLE(old))
return mnt;
if (!check_mnt(old) && old_path->dentry->d_op != &ns_dentry_operations)
return mnt;
if (!recurse && has_locked_children(old, old_path->dentry))
return mnt;
if (recurse)
mnt = copy_tree(old, old_path->dentry, CL_COPY_MNT_NS_FILE);
else
mnt = clone_mnt(old, old_path->dentry, 0);
if (!IS_ERR(mnt))
mnt->mnt.mnt_flags &= ~MNT_LOCKED;
return mnt;
}
/*
* do loopback mount.
*/
static int do_loopback(struct path *path, const char *old_name,
int recurse)
{
struct path old_path;
struct mount *mnt = NULL, *parent;
struct mountpoint *mp;
int err;
if (!old_name || !*old_name)
return -EINVAL;
err = kern_path(old_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path);
if (err)
return err;
err = -EINVAL;
if (mnt_ns_loop(old_path.dentry))
goto out;
mp = lock_mount(path);
if (IS_ERR(mp)) {
err = PTR_ERR(mp);
goto out;
}
parent = real_mount(path->mnt);
if (!check_mnt(parent))
goto out2;
mnt = __do_loopback(&old_path, recurse);
if (IS_ERR(mnt)) {
err = PTR_ERR(mnt);
goto out2;
}
err = graft_tree(mnt, parent, mp);
if (err) {
lock_mount_hash();
umount_tree(mnt, UMOUNT_SYNC);
unlock_mount_hash();
}
out2:
unlock_mount(mp);
out:
path_put(&old_path);
return err;
}
static struct file *open_detached_copy(struct path *path, bool recursive)
{
struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns;
struct mnt_namespace *ns = alloc_mnt_ns(user_ns, true);
struct mount *mnt, *p;
struct file *file;
if (IS_ERR(ns))
return ERR_CAST(ns);
namespace_lock();
mnt = __do_loopback(path, recursive);
if (IS_ERR(mnt)) {
namespace_unlock();
free_mnt_ns(ns);
return ERR_CAST(mnt);
}
lock_mount_hash();
for (p = mnt; p; p = next_mnt(p, mnt)) {
p->mnt_ns = ns;
ns->mounts++;
}
ns->root = mnt;
list_add_tail(&ns->list, &mnt->mnt_list);
mntget(&mnt->mnt);
unlock_mount_hash();
namespace_unlock();
mntput(path->mnt);
path->mnt = &mnt->mnt;
file = dentry_open(path, O_PATH, current_cred());
if (IS_ERR(file))
dissolve_on_fput(path->mnt);
else
file->f_mode |= FMODE_NEED_UNMOUNT;
return file;
}
SYSCALL_DEFINE3(open_tree, int, dfd, const char __user *, filename, unsigned, flags)
{
struct file *file;
struct path path;
int lookup_flags = LOOKUP_AUTOMOUNT | LOOKUP_FOLLOW;
bool detached = flags & OPEN_TREE_CLONE;
int error;
int fd;
BUILD_BUG_ON(OPEN_TREE_CLOEXEC != O_CLOEXEC);
if (flags & ~(AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_RECURSIVE |
AT_SYMLINK_NOFOLLOW | OPEN_TREE_CLONE |
OPEN_TREE_CLOEXEC))
return -EINVAL;
if ((flags & (AT_RECURSIVE | OPEN_TREE_CLONE)) == AT_RECURSIVE)
return -EINVAL;
if (flags & AT_NO_AUTOMOUNT)
lookup_flags &= ~LOOKUP_AUTOMOUNT;
if (flags & AT_SYMLINK_NOFOLLOW)
lookup_flags &= ~LOOKUP_FOLLOW;
if (flags & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
if (detached && !may_mount())
return -EPERM;
fd = get_unused_fd_flags(flags & O_CLOEXEC);
if (fd < 0)
return fd;
error = user_path_at(dfd, filename, lookup_flags, &path);
if (unlikely(error)) {
file = ERR_PTR(error);
} else {
if (detached)
file = open_detached_copy(&path, flags & AT_RECURSIVE);
else
file = dentry_open(&path, O_PATH, current_cred());
path_put(&path);
}
if (IS_ERR(file)) {
put_unused_fd(fd);
return PTR_ERR(file);
}
fd_install(fd, file);
return fd;
}
/*
* Don't allow locked mount flags to be cleared.
*
* No locks need to be held here while testing the various MNT_LOCK
* flags because those flags can never be cleared once they are set.
*/
static bool can_change_locked_flags(struct mount *mnt, unsigned int mnt_flags)
{
unsigned int fl = mnt->mnt.mnt_flags;
if ((fl & MNT_LOCK_READONLY) &&
!(mnt_flags & MNT_READONLY))
return false;
if ((fl & MNT_LOCK_NODEV) &&
!(mnt_flags & MNT_NODEV))
return false;
if ((fl & MNT_LOCK_NOSUID) &&
!(mnt_flags & MNT_NOSUID))
return false;
if ((fl & MNT_LOCK_NOEXEC) &&
!(mnt_flags & MNT_NOEXEC))
return false;
if ((fl & MNT_LOCK_ATIME) &&
((fl & MNT_ATIME_MASK) != (mnt_flags & MNT_ATIME_MASK)))
return false;
return true;
}
static int change_mount_ro_state(struct mount *mnt, unsigned int mnt_flags)
{
bool readonly_request = (mnt_flags & MNT_READONLY);
if (readonly_request == __mnt_is_readonly(&mnt->mnt))
return 0;
if (readonly_request)
return mnt_make_readonly(mnt);
mnt->mnt.mnt_flags &= ~MNT_READONLY;
return 0;
}
static void set_mount_attributes(struct mount *mnt, unsigned int mnt_flags)
{
mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
mnt->mnt.mnt_flags = mnt_flags;
touch_mnt_namespace(mnt->mnt_ns);
}
static void mnt_warn_timestamp_expiry(struct path *mountpoint, struct vfsmount *mnt)
{
struct super_block *sb = mnt->mnt_sb;
if (!__mnt_is_readonly(mnt) &&
(!(sb->s_iflags & SB_I_TS_EXPIRY_WARNED)) &&
(ktime_get_real_seconds() + TIME_UPTIME_SEC_MAX > sb->s_time_max)) {
char *buf = (char *)__get_free_page(GFP_KERNEL);
char *mntpath = buf ? d_path(mountpoint, buf, PAGE_SIZE) : ERR_PTR(-ENOMEM);
pr_warn("%s filesystem being %s at %s supports timestamps until %ptTd (0x%llx)\n",
sb->s_type->name,
is_mounted(mnt) ? "remounted" : "mounted",
mntpath, &sb->s_time_max,
(unsigned long long)sb->s_time_max);
free_page((unsigned long)buf);
sb->s_iflags |= SB_I_TS_EXPIRY_WARNED;
}
}
/*
* Handle reconfiguration of the mountpoint only without alteration of the
* superblock it refers to. This is triggered by specifying MS_REMOUNT|MS_BIND
* to mount(2).
*/
static int do_reconfigure_mnt(struct path *path, unsigned int mnt_flags)
{
struct super_block *sb = path->mnt->mnt_sb;
struct mount *mnt = real_mount(path->mnt);
int ret;
if (!check_mnt(mnt))
return -EINVAL;
if (!path_mounted(path))
return -EINVAL;
if (!can_change_locked_flags(mnt, mnt_flags))
return -EPERM;
/*
* We're only checking whether the superblock is read-only not
* changing it, so only take down_read(&sb->s_umount).
*/
down_read(&sb->s_umount);
lock_mount_hash();
ret = change_mount_ro_state(mnt, mnt_flags);
if (ret == 0)
set_mount_attributes(mnt, mnt_flags);
unlock_mount_hash();
up_read(&sb->s_umount);
mnt_warn_timestamp_expiry(path, &mnt->mnt);
return ret;
}
/*
* change filesystem flags. dir should be a physical root of filesystem.
* If you've mounted a non-root directory somewhere and want to do remount
* on it - tough luck.
*/
static int do_remount(struct path *path, int ms_flags, int sb_flags,
int mnt_flags, void *data)
{
int err;
struct super_block *sb = path->mnt->mnt_sb;
struct mount *mnt = real_mount(path->mnt);
struct fs_context *fc;
if (!check_mnt(mnt))
return -EINVAL;
if (!path_mounted(path))
return -EINVAL;
if (!can_change_locked_flags(mnt, mnt_flags))
return -EPERM;
fc = fs_context_for_reconfigure(path->dentry, sb_flags, MS_RMT_MASK);
if (IS_ERR(fc))
return PTR_ERR(fc);
fc->oldapi = true;
err = parse_monolithic_mount_data(fc, data);
if (!err) {
down_write(&sb->s_umount);
err = -EPERM;
if (ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
err = reconfigure_super(fc);
if (!err) {
lock_mount_hash();
set_mount_attributes(mnt, mnt_flags);
unlock_mount_hash();
}
}
up_write(&sb->s_umount);
}
mnt_warn_timestamp_expiry(path, &mnt->mnt);
put_fs_context(fc);
return err;
}
static inline int tree_contains_unbindable(struct mount *mnt)
{
struct mount *p;
for (p = mnt; p; p = next_mnt(p, mnt)) {
if (IS_MNT_UNBINDABLE(p))
return 1;
}
return 0;
}
/*
* Check that there aren't references to earlier/same mount namespaces in the
* specified subtree. Such references can act as pins for mount namespaces
* that aren't checked by the mount-cycle checking code, thereby allowing
* cycles to be made.
*/
static bool check_for_nsfs_mounts(struct mount *subtree)
{
struct mount *p;
bool ret = false;
lock_mount_hash();
for (p = subtree; p; p = next_mnt(p, subtree))
if (mnt_ns_loop(p->mnt.mnt_root))
goto out;
ret = true;
out:
unlock_mount_hash();
return ret;
}
static int do_set_group(struct path *from_path, struct path *to_path)
{
struct mount *from, *to;
int err;
from = real_mount(from_path->mnt);
to = real_mount(to_path->mnt);
namespace_lock();
err = -EINVAL;
/* To and From must be mounted */
if (!is_mounted(&from->mnt))
goto out;
if (!is_mounted(&to->mnt))
goto out;
err = -EPERM;
/* We should be allowed to modify mount namespaces of both mounts */
if (!ns_capable(from->mnt_ns->user_ns, CAP_SYS_ADMIN))
goto out;
if (!ns_capable(to->mnt_ns->user_ns, CAP_SYS_ADMIN))
goto out;
err = -EINVAL;
/* To and From paths should be mount roots */
if (!path_mounted(from_path))
goto out;
if (!path_mounted(to_path))
goto out;
/* Setting sharing groups is only allowed across same superblock */
if (from->mnt.mnt_sb != to->mnt.mnt_sb)
goto out;
/* From mount root should be wider than To mount root */
if (!is_subdir(to->mnt.mnt_root, from->mnt.mnt_root))
goto out;
/* From mount should not have locked children in place of To's root */
if (has_locked_children(from, to->mnt.mnt_root))
goto out;
/* Setting sharing groups is only allowed on private mounts */
if (IS_MNT_SHARED(to) || IS_MNT_SLAVE(to))
goto out;
/* From should not be private */
if (!IS_MNT_SHARED(from) && !IS_MNT_SLAVE(from))
goto out;
if (IS_MNT_SLAVE(from)) {
struct mount *m = from->mnt_master;
list_add(&to->mnt_slave, &m->mnt_slave_list);
to->mnt_master = m;
}
if (IS_MNT_SHARED(from)) {
to->mnt_group_id = from->mnt_group_id;
list_add(&to->mnt_share, &from->mnt_share);
lock_mount_hash();
set_mnt_shared(to);
unlock_mount_hash();
}
err = 0;
out:
namespace_unlock();
return err;
}
/**
* path_overmounted - check if path is overmounted
* @path: path to check
*
* Check if path is overmounted, i.e., if there's a mount on top of
* @path->mnt with @path->dentry as mountpoint.
*
* Context: This function expects namespace_lock() to be held.
* Return: If path is overmounted true is returned, false if not.
*/
static inline bool path_overmounted(const struct path *path)
{
rcu_read_lock();
if (unlikely(__lookup_mnt(path->mnt, path->dentry))) {
rcu_read_unlock();
return true;
}
rcu_read_unlock();
return false;
}
/**
* can_move_mount_beneath - check that we can mount beneath the top mount
* @from: mount to mount beneath
* @to: mount under which to mount
*
* - Make sure that @to->dentry is actually the root of a mount under
* which we can mount another mount.
* - Make sure that nothing can be mounted beneath the caller's current
* root or the rootfs of the namespace.
* - Make sure that the caller can unmount the topmost mount ensuring
* that the caller could reveal the underlying mountpoint.
* - Ensure that nothing has been mounted on top of @from before we
* grabbed @namespace_sem to avoid creating pointless shadow mounts.
* - Prevent mounting beneath a mount if the propagation relationship
* between the source mount, parent mount, and top mount would lead to
* nonsensical mount trees.
*
* Context: This function expects namespace_lock() to be held.
* Return: On success 0, and on error a negative error code is returned.
*/
static int can_move_mount_beneath(const struct path *from,
const struct path *to,
const struct mountpoint *mp)
{
struct mount *mnt_from = real_mount(from->mnt),
*mnt_to = real_mount(to->mnt),
*parent_mnt_to = mnt_to->mnt_parent;
if (!mnt_has_parent(mnt_to))
return -EINVAL;
if (!path_mounted(to))
return -EINVAL;
if (IS_MNT_LOCKED(mnt_to))
return -EINVAL;
/* Avoid creating shadow mounts during mount propagation. */
if (path_overmounted(from))
return -EINVAL;
/*
* Mounting beneath the rootfs only makes sense when the
* semantics of pivot_root(".", ".") are used.
*/
if (&mnt_to->mnt == current->fs->root.mnt)
return -EINVAL;
if (parent_mnt_to == current->nsproxy->mnt_ns->root)
return -EINVAL;
for (struct mount *p = mnt_from; mnt_has_parent(p); p = p->mnt_parent)
if (p == mnt_to)
return -EINVAL;
/*
* If the parent mount propagates to the child mount this would
* mean mounting @mnt_from on @mnt_to->mnt_parent and then
* propagating a copy @c of @mnt_from on top of @mnt_to. This
* defeats the whole purpose of mounting beneath another mount.
*/
if (propagation_would_overmount(parent_mnt_to, mnt_to, mp))
return -EINVAL;
/*
* If @mnt_to->mnt_parent propagates to @mnt_from this would
* mean propagating a copy @c of @mnt_from on top of @mnt_from.
* Afterwards @mnt_from would be mounted on top of
* @mnt_to->mnt_parent and @mnt_to would be unmounted from
* @mnt->mnt_parent and remounted on @mnt_from. But since @c is
* already mounted on @mnt_from, @mnt_to would ultimately be
* remounted on top of @c. Afterwards, @mnt_from would be
* covered by a copy @c of @mnt_from and @c would be covered by
* @mnt_from itself. This defeats the whole purpose of mounting
* @mnt_from beneath @mnt_to.
*/
if (propagation_would_overmount(parent_mnt_to, mnt_from, mp))
return -EINVAL;
return 0;
}
static int do_move_mount(struct path *old_path, struct path *new_path,
bool beneath)
{
struct mnt_namespace *ns;
struct mount *p;
struct mount *old;
struct mount *parent;
struct mountpoint *mp, *old_mp;
int err;
bool attached;
enum mnt_tree_flags_t flags = 0;
mp = do_lock_mount(new_path, beneath);
if (IS_ERR(mp))
return PTR_ERR(mp);
old = real_mount(old_path->mnt);
p = real_mount(new_path->mnt);
parent = old->mnt_parent;
attached = mnt_has_parent(old);
if (attached)
flags |= MNT_TREE_MOVE;
old_mp = old->mnt_mp;
ns = old->mnt_ns;
err = -EINVAL;
/* The mountpoint must be in our namespace. */
if (!check_mnt(p))
goto out;
/* The thing moved must be mounted... */
if (!is_mounted(&old->mnt))
goto out;
/* ... and either ours or the root of anon namespace */
if (!(attached ? check_mnt(old) : is_anon_ns(ns)))
goto out;
if (old->mnt.mnt_flags & MNT_LOCKED)
goto out;
if (!path_mounted(old_path))
goto out;
if (d_is_dir(new_path->dentry) !=
d_is_dir(old_path->dentry))
goto out;
/*
* Don't move a mount residing in a shared parent.
*/
if (attached && IS_MNT_SHARED(parent))
goto out;
if (beneath) {
err = can_move_mount_beneath(old_path, new_path, mp);
if (err)
goto out;
err = -EINVAL;
p = p->mnt_parent;
flags |= MNT_TREE_BENEATH;
}
/*
* Don't move a mount tree containing unbindable mounts to a destination
* mount which is shared.
*/
if (IS_MNT_SHARED(p) && tree_contains_unbindable(old))
goto out;
err = -ELOOP;
if (!check_for_nsfs_mounts(old))
goto out;
for (; mnt_has_parent(p); p = p->mnt_parent)
if (p == old)
goto out;
err = attach_recursive_mnt(old, real_mount(new_path->mnt), mp, flags);
if (err)
goto out;
/* if the mount is moved, it should no longer be expire
* automatically */
list_del_init(&old->mnt_expire);
if (attached)
put_mountpoint(old_mp);
out:
unlock_mount(mp);
if (!err) {
if (attached)
mntput_no_expire(parent);
else
free_mnt_ns(ns);
}
return err;
}
static int do_move_mount_old(struct path *path, const char *old_name)
{
struct path old_path;
int err;
if (!old_name || !*old_name)
return -EINVAL;
err = kern_path(old_name, LOOKUP_FOLLOW, &old_path);
if (err)
return err;
err = do_move_mount(&old_path, path, false);
path_put(&old_path);
return err;
}
/*
* add a mount into a namespace's mount tree
*/
static int do_add_mount(struct mount *newmnt, struct mountpoint *mp,
const struct path *path, int mnt_flags)
{
struct mount *parent = real_mount(path->mnt);
mnt_flags &= ~MNT_INTERNAL_FLAGS;
if (unlikely(!check_mnt(parent))) {
/* that's acceptable only for automounts done in private ns */
if (!(mnt_flags & MNT_SHRINKABLE))
return -EINVAL;
/* ... and for those we'd better have mountpoint still alive */
if (!parent->mnt_ns)
return -EINVAL;
}
/* Refuse the same filesystem on the same mount point */
if (path->mnt->mnt_sb == newmnt->mnt.mnt_sb && path_mounted(path))
return -EBUSY;
if (d_is_symlink(newmnt->mnt.mnt_root))
return -EINVAL;
newmnt->mnt.mnt_flags = mnt_flags;
return graft_tree(newmnt, parent, mp);
}
static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags);
/*
* Create a new mount using a superblock configuration and request it
* be added to the namespace tree.
*/
static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint,
unsigned int mnt_flags)
{
struct vfsmount *mnt;
struct mountpoint *mp;
struct super_block *sb = fc->root->d_sb;
int error;
error = security_sb_kern_mount(sb);
if (!error && mount_too_revealing(sb, &mnt_flags))
error = -EPERM;
if (unlikely(error)) {
fc_drop_locked(fc);
return error;
}
up_write(&sb->s_umount);
mnt = vfs_create_mount(fc);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
mnt_warn_timestamp_expiry(mountpoint, mnt);
mp = lock_mount(mountpoint);
if (IS_ERR(mp)) {
mntput(mnt);
return PTR_ERR(mp);
}
error = do_add_mount(real_mount(mnt), mp, mountpoint, mnt_flags);
unlock_mount(mp);
if (error < 0)
mntput(mnt);
return error;
}
/*
* create a new mount for userspace and request it to be added into the
* namespace's tree
*/
static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
int mnt_flags, const char *name, void *data)
{
struct file_system_type *type;
struct fs_context *fc;
const char *subtype = NULL;
int err = 0;
if (!fstype)
return -EINVAL;
type = get_fs_type(fstype);
if (!type)
return -ENODEV;
if (type->fs_flags & FS_HAS_SUBTYPE) {
subtype = strchr(fstype, '.');
if (subtype) {
subtype++;
if (!*subtype) {
put_filesystem(type);
return -EINVAL;
}
}
}
fc = fs_context_for_mount(type, sb_flags);
put_filesystem(type);
if (IS_ERR(fc))
return PTR_ERR(fc);
if (subtype)
err = vfs_parse_fs_string(fc, "subtype",
subtype, strlen(subtype));
if (!err && name)
err = vfs_parse_fs_string(fc, "source", name, strlen(name));
if (!err)
err = parse_monolithic_mount_data(fc, data);
if (!err && !mount_capable(fc))
err = -EPERM;
if (!err)
err = vfs_get_tree(fc);
if (!err)
err = do_new_mount_fc(fc, path, mnt_flags);
put_fs_context(fc);
return err;
}
int finish_automount(struct vfsmount *m, const struct path *path)
{
struct dentry *dentry = path->dentry;
struct mountpoint *mp;
struct mount *mnt;
int err;
if (!m)
return 0;
if (IS_ERR(m))
return PTR_ERR(m);
mnt = real_mount(m);
/* The new mount record should have at least 2 refs to prevent it being
* expired before we get a chance to add it
*/
BUG_ON(mnt_get_count(mnt) < 2);
if (m->mnt_sb == path->mnt->mnt_sb &&
m->mnt_root == dentry) {
err = -ELOOP;
goto discard;
}
/*
* we don't want to use lock_mount() - in this case finding something
* that overmounts our mountpoint to be means "quitely drop what we've
* got", not "try to mount it on top".
*/
inode_lock(dentry->d_inode);
namespace_lock();
if (unlikely(cant_mount(dentry))) {
err = -ENOENT;
goto discard_locked;
}
if (path_overmounted(path)) {
err = 0;
goto discard_locked;
}
mp = get_mountpoint(dentry);
if (IS_ERR(mp)) {
err = PTR_ERR(mp);
goto discard_locked;
}
err = do_add_mount(mnt, mp, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
unlock_mount(mp);
if (unlikely(err))
goto discard;
mntput(m);
return 0;
discard_locked:
namespace_unlock();
inode_unlock(dentry->d_inode);
discard:
/* remove m from any expiration list it may be on */
if (!list_empty(&mnt->mnt_expire)) {
namespace_lock();
list_del_init(&mnt->mnt_expire);
namespace_unlock();
}
mntput(m);
mntput(m);
return err;
}
/**
* mnt_set_expiry - Put a mount on an expiration list
* @mnt: The mount to list.
* @expiry_list: The list to add the mount to.
*/
void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list)
{
namespace_lock();
list_add_tail(&real_mount(mnt)->mnt_expire, expiry_list);
namespace_unlock();
}
EXPORT_SYMBOL(mnt_set_expiry);
/*
* process a list of expirable mountpoints with the intent of discarding any
* mountpoints that aren't in use and haven't been touched since last we came
* here
*/
void mark_mounts_for_expiry(struct list_head *mounts)
{
struct mount *mnt, *next;
LIST_HEAD(graveyard);
if (list_empty(mounts))
return;
namespace_lock();
lock_mount_hash();
/* extract from the expiration list every vfsmount that matches the
* following criteria:
* - only referenced by its parent vfsmount
* - still marked for expiry (marked on the last call here; marks are
* cleared by mntput())
*/
list_for_each_entry_safe(mnt, next, mounts, mnt_expire) {
if (!xchg(&mnt->mnt_expiry_mark, 1) ||
propagate_mount_busy(mnt, 1))
continue;
list_move(&mnt->mnt_expire, &graveyard);
}
while (!list_empty(&graveyard)) {
mnt = list_first_entry(&graveyard, struct mount, mnt_expire);
touch_mnt_namespace(mnt->mnt_ns);
umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
}
unlock_mount_hash();
namespace_unlock();
}
EXPORT_SYMBOL_GPL(mark_mounts_for_expiry);
/*
* Ripoff of 'select_parent()'
*
* search the list of submounts for a given mountpoint, and move any
* shrinkable submounts to the 'graveyard' list.
*/
static int select_submounts(struct mount *parent, struct list_head *graveyard)
{
struct mount *this_parent = parent;
struct list_head *next;
int found = 0;
repeat:
next = this_parent->mnt_mounts.next;
resume:
while (next != &this_parent->mnt_mounts) {
struct list_head *tmp = next;
struct mount *mnt = list_entry(tmp, struct mount, mnt_child);
next = tmp->next;
if (!(mnt->mnt.mnt_flags & MNT_SHRINKABLE))
continue;
/*
* Descend a level if the d_mounts list is non-empty.
*/
if (!list_empty(&mnt->mnt_mounts)) {
this_parent = mnt;
goto repeat;
}
if (!propagate_mount_busy(mnt, 1)) {
list_move_tail(&mnt->mnt_expire, graveyard);
found++;
}
}
/*
* All done at this level ... ascend and resume the search
*/
if (this_parent != parent) {
next = this_parent->mnt_child.next;
this_parent = this_parent->mnt_parent;
goto resume;
}
return found;
}
/*
* process a list of expirable mountpoints with the intent of discarding any
* submounts of a specific parent mountpoint
*
* mount_lock must be held for write
*/
static void shrink_submounts(struct mount *mnt)
{
LIST_HEAD(graveyard);
struct mount *m;
/* extract submounts of 'mountpoint' from the expiration list */
while (select_submounts(mnt, &graveyard)) {
while (!list_empty(&graveyard)) {
m = list_first_entry(&graveyard, struct mount,
mnt_expire);
touch_mnt_namespace(m->mnt_ns);
umount_tree(m, UMOUNT_PROPAGATE|UMOUNT_SYNC);
}
}
}
static void *copy_mount_options(const void __user * data)
{
char *copy;
unsigned left, offset;
if (!data)
return NULL;
copy = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!copy)
return ERR_PTR(-ENOMEM);
left = copy_from_user(copy, data, PAGE_SIZE);
/*
* Not all architectures have an exact copy_from_user(). Resort to
* byte at a time.
*/
offset = PAGE_SIZE - left;
while (left) {
char c;
if (get_user(c, (const char __user *)data + offset))
break;
copy[offset] = c;
left--;
offset++;
}
if (left == PAGE_SIZE) {
kfree(copy);
return ERR_PTR(-EFAULT);
}
return copy;
}
static char *copy_mount_string(const void __user *data)
{
return data ? strndup_user(data, PATH_MAX) : NULL;
}
/*
* Flags is a 32-bit value that allows up to 31 non-fs dependent flags to
* be given to the mount() call (ie: read-only, no-dev, no-suid etc).
*
* data is a (void *) that can point to any structure up to
* PAGE_SIZE-1 bytes, which can contain arbitrary fs-dependent
* information (or be NULL).
*
* Pre-0.97 versions of mount() didn't have a flags word.
* When the flags word was introduced its top half was required
* to have the magic value 0xC0ED, and this remained so until 2.4.0-test9.
* Therefore, if this magic number is present, it carries no information
* and must be discarded.
*/
int path_mount(const char *dev_name, struct path *path,
const char *type_page, unsigned long flags, void *data_page)
{
unsigned int mnt_flags = 0, sb_flags;
int ret;
/* Discard magic */
if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
flags &= ~MS_MGC_MSK;
/* Basic sanity checks */
if (data_page)
((char *)data_page)[PAGE_SIZE - 1] = 0;
if (flags & MS_NOUSER)
return -EINVAL;
ret = security_sb_mount(dev_name, path, type_page, flags, data_page);
if (ret)
return ret;
if (!may_mount())
return -EPERM;
if (flags & SB_MANDLOCK)
warn_mandlock();
/* Default to relatime unless overriden */
if (!(flags & MS_NOATIME))
mnt_flags |= MNT_RELATIME;
/* Separate the per-mountpoint flags */
if (flags & MS_NOSUID)
mnt_flags |= MNT_NOSUID;
if (flags & MS_NODEV)
mnt_flags |= MNT_NODEV;
if (flags & MS_NOEXEC)
mnt_flags |= MNT_NOEXEC;
if (flags & MS_NOATIME)
mnt_flags |= MNT_NOATIME;
if (flags & MS_NODIRATIME)
mnt_flags |= MNT_NODIRATIME;
if (flags & MS_STRICTATIME)
mnt_flags &= ~(MNT_RELATIME | MNT_NOATIME);
if (flags & MS_RDONLY)
mnt_flags |= MNT_READONLY;
if (flags & MS_NOSYMFOLLOW)
mnt_flags |= MNT_NOSYMFOLLOW;
/* The default atime for remount is preservation */
if ((flags & MS_REMOUNT) &&
((flags & (MS_NOATIME | MS_NODIRATIME | MS_RELATIME |
MS_STRICTATIME)) == 0)) {
mnt_flags &= ~MNT_ATIME_MASK;
mnt_flags |= path->mnt->mnt_flags & MNT_ATIME_MASK;
}
sb_flags = flags & (SB_RDONLY |
SB_SYNCHRONOUS |
SB_MANDLOCK |
SB_DIRSYNC |
SB_SILENT |
SB_POSIXACL |
SB_LAZYTIME |
SB_I_VERSION);
if ((flags & (MS_REMOUNT | MS_BIND)) == (MS_REMOUNT | MS_BIND))
return do_reconfigure_mnt(path, mnt_flags);
if (flags & MS_REMOUNT)
return do_remount(path, flags, sb_flags, mnt_flags, data_page);
if (flags & MS_BIND)
return do_loopback(path, dev_name, flags & MS_REC);
if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
return do_change_type(path, flags);
if (flags & MS_MOVE)
return do_move_mount_old(path, dev_name);
return do_new_mount(path, type_page, sb_flags, mnt_flags, dev_name,
data_page);
}
long do_mount(const char *dev_name, const char __user *dir_name,
const char *type_page, unsigned long flags, void *data_page)
{
struct path path;
int ret;
ret = user_path_at(AT_FDCWD, dir_name, LOOKUP_FOLLOW, &path);
if (ret)
return ret;
ret = path_mount(dev_name, &path, type_page, flags, data_page);
path_put(&path);
return ret;
}
static struct ucounts *inc_mnt_namespaces(struct user_namespace *ns)
{
return inc_ucount(ns, current_euid(), UCOUNT_MNT_NAMESPACES);
}
static void dec_mnt_namespaces(struct ucounts *ucounts)
{
dec_ucount(ucounts, UCOUNT_MNT_NAMESPACES);
}
static void free_mnt_ns(struct mnt_namespace *ns)
{
if (!is_anon_ns(ns))
ns_free_inum(&ns->ns);
dec_mnt_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
kfree(ns);
}
/*
* Assign a sequence number so we can detect when we attempt to bind
* mount a reference to an older mount namespace into the current
* mount namespace, preventing reference counting loops. A 64bit
* number incrementing at 10Ghz will take 12,427 years to wrap which
* is effectively never, so we can ignore the possibility.
*/
static atomic64_t mnt_ns_seq = ATOMIC64_INIT(1);
static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool anon)
{
struct mnt_namespace *new_ns;
struct ucounts *ucounts;
int ret;
ucounts = inc_mnt_namespaces(user_ns);
if (!ucounts)
return ERR_PTR(-ENOSPC);
new_ns = kzalloc(sizeof(struct mnt_namespace), GFP_KERNEL_ACCOUNT);
if (!new_ns) {
dec_mnt_namespaces(ucounts);
return ERR_PTR(-ENOMEM);
}
if (!anon) {
ret = ns_alloc_inum(&new_ns->ns);
if (ret) {
kfree(new_ns);
dec_mnt_namespaces(ucounts);
return ERR_PTR(ret);
}
}
new_ns->ns.ops = &mntns_operations;
if (!anon)
new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
refcount_set(&new_ns->ns.count, 1);
INIT_LIST_HEAD(&new_ns->list);
init_waitqueue_head(&new_ns->poll);
spin_lock_init(&new_ns->ns_lock);
new_ns->user_ns = get_user_ns(user_ns);
new_ns->ucounts = ucounts;
return new_ns;
}
__latent_entropy
struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
struct user_namespace *user_ns, struct fs_struct *new_fs)
{
struct mnt_namespace *new_ns;
struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
struct mount *p, *q;
struct mount *old;
struct mount *new;
int copy_flags;
BUG_ON(!ns);
if (likely(!(flags & CLONE_NEWNS))) {
get_mnt_ns(ns);
return ns;
}
old = ns->root;
new_ns = alloc_mnt_ns(user_ns, false);
if (IS_ERR(new_ns))
return new_ns;
namespace_lock();
/* First pass: copy the tree topology */
copy_flags = CL_COPY_UNBINDABLE | CL_EXPIRE;
if (user_ns != ns->user_ns)
copy_flags |= CL_SHARED_TO_SLAVE;
new = copy_tree(old, old->mnt.mnt_root, copy_flags);
if (IS_ERR(new)) {
namespace_unlock();
free_mnt_ns(new_ns);
return ERR_CAST(new);
}
if (user_ns != ns->user_ns) {
lock_mount_hash();
lock_mnt_tree(new);
unlock_mount_hash();
}
new_ns->root = new;
list_add_tail(&new_ns->list, &new->mnt_list);
/*
* Second pass: switch the tsk->fs->* elements and mark new vfsmounts
* as belonging to new namespace. We have already acquired a private
* fs_struct, so tsk->fs->lock is not needed.
*/
p = old;
q = new;
while (p) {
q->mnt_ns = new_ns;
new_ns->mounts++;
if (new_fs) {
if (&p->mnt == new_fs->root.mnt) {
new_fs->root.mnt = mntget(&q->mnt);
rootmnt = &p->mnt;
}
if (&p->mnt == new_fs->pwd.mnt) {
new_fs->pwd.mnt = mntget(&q->mnt);
pwdmnt = &p->mnt;
}
}
p = next_mnt(p, old);
q = next_mnt(q, new);
if (!q)
break;
// an mntns binding we'd skipped?
while (p->mnt.mnt_root != q->mnt.mnt_root)
p = next_mnt(skip_mnt_tree(p), old);
}
namespace_unlock();
if (rootmnt)
mntput(rootmnt);
if (pwdmnt)
mntput(pwdmnt);
return new_ns;
}
struct dentry *mount_subtree(struct vfsmount *m, const char *name)
{
struct mount *mnt = real_mount(m);
struct mnt_namespace *ns;
struct super_block *s;
struct path path;
int err;
ns = alloc_mnt_ns(&init_user_ns, true);
if (IS_ERR(ns)) {
mntput(m);
return ERR_CAST(ns);
}
mnt->mnt_ns = ns;
ns->root = mnt;
ns->mounts++;
list_add(&mnt->mnt_list, &ns->list);
err = vfs_path_lookup(m->mnt_root, m,
name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
put_mnt_ns(ns);
if (err)
return ERR_PTR(err);
/* trade a vfsmount reference for active sb one */
s = path.mnt->mnt_sb;
atomic_inc(&s->s_active);
mntput(path.mnt);
/* lock the sucker */
down_write(&s->s_umount);
/* ... and return the root of (sub)tree on it */
return path.dentry;
}
EXPORT_SYMBOL(mount_subtree);
SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
char __user *, type, unsigned long, flags, void __user *, data)
{
int ret;
char *kernel_type;
char *kernel_dev;
void *options;
kernel_type = copy_mount_string(type);
ret = PTR_ERR(kernel_type);
if (IS_ERR(kernel_type))
goto out_type;
kernel_dev = copy_mount_string(dev_name);
ret = PTR_ERR(kernel_dev);
if (IS_ERR(kernel_dev))
goto out_dev;
options = copy_mount_options(data);
ret = PTR_ERR(options);
if (IS_ERR(options))
goto out_data;
ret = do_mount(kernel_dev, dir_name, kernel_type, flags, options);
kfree(options);
out_data:
kfree(kernel_dev);
out_dev:
kfree(kernel_type);
out_type:
return ret;
}
#define FSMOUNT_VALID_FLAGS \
(MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOSUID | MOUNT_ATTR_NODEV | \
MOUNT_ATTR_NOEXEC | MOUNT_ATTR__ATIME | MOUNT_ATTR_NODIRATIME | \
MOUNT_ATTR_NOSYMFOLLOW)
#define MOUNT_SETATTR_VALID_FLAGS (FSMOUNT_VALID_FLAGS | MOUNT_ATTR_IDMAP)
#define MOUNT_SETATTR_PROPAGATION_FLAGS \
(MS_UNBINDABLE | MS_PRIVATE | MS_SLAVE | MS_SHARED)
static unsigned int attr_flags_to_mnt_flags(u64 attr_flags)
{
unsigned int mnt_flags = 0;
if (attr_flags & MOUNT_ATTR_RDONLY)
mnt_flags |= MNT_READONLY;
if (attr_flags & MOUNT_ATTR_NOSUID)
mnt_flags |= MNT_NOSUID;
if (attr_flags & MOUNT_ATTR_NODEV)
mnt_flags |= MNT_NODEV;
if (attr_flags & MOUNT_ATTR_NOEXEC)
mnt_flags |= MNT_NOEXEC;
if (attr_flags & MOUNT_ATTR_NODIRATIME)
mnt_flags |= MNT_NODIRATIME;
if (attr_flags & MOUNT_ATTR_NOSYMFOLLOW)
mnt_flags |= MNT_NOSYMFOLLOW;
return mnt_flags;
}
/*
* Create a kernel mount representation for a new, prepared superblock
* (specified by fs_fd) and attach to an open_tree-like file descriptor.
*/
SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
unsigned int, attr_flags)
{
struct mnt_namespace *ns;
struct fs_context *fc;
struct file *file;
struct path newmount;
struct mount *mnt;
struct fd f;
unsigned int mnt_flags = 0;
long ret;
if (!may_mount())
return -EPERM;
if ((flags & ~(FSMOUNT_CLOEXEC)) != 0)
return -EINVAL;
if (attr_flags & ~FSMOUNT_VALID_FLAGS)
return -EINVAL;
mnt_flags = attr_flags_to_mnt_flags(attr_flags);
switch (attr_flags & MOUNT_ATTR__ATIME) {
case MOUNT_ATTR_STRICTATIME:
break;
case MOUNT_ATTR_NOATIME:
mnt_flags |= MNT_NOATIME;
break;
case MOUNT_ATTR_RELATIME:
mnt_flags |= MNT_RELATIME;
break;
default:
return -EINVAL;
}
f = fdget(fs_fd);
if (!f.file)
return -EBADF;
ret = -EINVAL;
if (f.file->f_op != &fscontext_fops)
goto err_fsfd;
fc = f.file->private_data;
ret = mutex_lock_interruptible(&fc->uapi_mutex);
if (ret < 0)
goto err_fsfd;
/* There must be a valid superblock or we can't mount it */
ret = -EINVAL;
if (!fc->root)
goto err_unlock;
ret = -EPERM;
if (mount_too_revealing(fc->root->d_sb, &mnt_flags)) {
pr_warn("VFS: Mount too revealing\n");
goto err_unlock;
}
ret = -EBUSY;
if (fc->phase != FS_CONTEXT_AWAITING_MOUNT)
goto err_unlock;
if (fc->sb_flags & SB_MANDLOCK)
warn_mandlock();
newmount.mnt = vfs_create_mount(fc);
if (IS_ERR(newmount.mnt)) {
ret = PTR_ERR(newmount.mnt);
goto err_unlock;
}
newmount.dentry = dget(fc->root);
newmount.mnt->mnt_flags = mnt_flags;
/* We've done the mount bit - now move the file context into more or
* less the same state as if we'd done an fspick(). We don't want to
* do any memory allocation or anything like that at this point as we
* don't want to have to handle any errors incurred.
*/
vfs_clean_context(fc);
ns = alloc_mnt_ns(current->nsproxy->mnt_ns->user_ns, true);
if (IS_ERR(ns)) {
ret = PTR_ERR(ns);
goto err_path;
}
mnt = real_mount(newmount.mnt);
mnt->mnt_ns = ns;
ns->root = mnt;
ns->mounts = 1;
list_add(&mnt->mnt_list, &ns->list);
mntget(newmount.mnt);
/* Attach to an apparent O_PATH fd with a note that we need to unmount
* it, not just simply put it.
*/
file = dentry_open(&newmount, O_PATH, fc->cred);
if (IS_ERR(file)) {
dissolve_on_fput(newmount.mnt);
ret = PTR_ERR(file);
goto err_path;
}
file->f_mode |= FMODE_NEED_UNMOUNT;
ret = get_unused_fd_flags((flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0);
if (ret >= 0)
fd_install(ret, file);
else
fput(file);
err_path:
path_put(&newmount);
err_unlock:
mutex_unlock(&fc->uapi_mutex);
err_fsfd:
fdput(f);
return ret;
}
/*
* Move a mount from one place to another. In combination with
* fsopen()/fsmount() this is used to install a new mount and in combination
* with open_tree(OPEN_TREE_CLONE [| AT_RECURSIVE]) it can be used to copy
* a mount subtree.
*
* Note the flags value is a combination of MOVE_MOUNT_* flags.
*/
SYSCALL_DEFINE5(move_mount,
int, from_dfd, const char __user *, from_pathname,
int, to_dfd, const char __user *, to_pathname,
unsigned int, flags)
{
struct path from_path, to_path;
unsigned int lflags;
int ret = 0;
if (!may_mount())
return -EPERM;
if (flags & ~MOVE_MOUNT__MASK)
return -EINVAL;
if ((flags & (MOVE_MOUNT_BENEATH | MOVE_MOUNT_SET_GROUP)) ==
(MOVE_MOUNT_BENEATH | MOVE_MOUNT_SET_GROUP))
return -EINVAL;
/* If someone gives a pathname, they aren't permitted to move
* from an fd that requires unmount as we can't get at the flag
* to clear it afterwards.
*/
lflags = 0;
if (flags & MOVE_MOUNT_F_SYMLINKS) lflags |= LOOKUP_FOLLOW;
if (flags & MOVE_MOUNT_F_AUTOMOUNTS) lflags |= LOOKUP_AUTOMOUNT;
if (flags & MOVE_MOUNT_F_EMPTY_PATH) lflags |= LOOKUP_EMPTY;
ret = user_path_at(from_dfd, from_pathname, lflags, &from_path);
if (ret < 0)
return ret;
lflags = 0;
if (flags & MOVE_MOUNT_T_SYMLINKS) lflags |= LOOKUP_FOLLOW;
if (flags & MOVE_MOUNT_T_AUTOMOUNTS) lflags |= LOOKUP_AUTOMOUNT;
if (flags & MOVE_MOUNT_T_EMPTY_PATH) lflags |= LOOKUP_EMPTY;
ret = user_path_at(to_dfd, to_pathname, lflags, &to_path);
if (ret < 0)
goto out_from;
ret = security_move_mount(&from_path, &to_path);
if (ret < 0)
goto out_to;
if (flags & MOVE_MOUNT_SET_GROUP)
ret = do_set_group(&from_path, &to_path);
else
ret = do_move_mount(&from_path, &to_path,
(flags & MOVE_MOUNT_BENEATH));
out_to:
path_put(&to_path);
out_from:
path_put(&from_path);
return ret;
}
/*
* Return true if path is reachable from root
*
* namespace_sem or mount_lock is held
*/
bool is_path_reachable(struct mount *mnt, struct dentry *dentry,
const struct path *root)
{
while (&mnt->mnt != root->mnt && mnt_has_parent(mnt)) {
dentry = mnt->mnt_mountpoint;
mnt = mnt->mnt_parent;
}
return &mnt->mnt == root->mnt && is_subdir(dentry, root->dentry);
}
bool path_is_under(const struct path *path1, const struct path *path2)
{
bool res;
read_seqlock_excl(&mount_lock);
res = is_path_reachable(real_mount(path1->mnt), path1->dentry, path2);
read_sequnlock_excl(&mount_lock);
return res;
}
EXPORT_SYMBOL(path_is_under);
/*
* pivot_root Semantics:
* Moves the root file system of the current process to the directory put_old,
* makes new_root as the new root file system of the current process, and sets
* root/cwd of all processes which had them on the current root to new_root.
*
* Restrictions:
* The new_root and put_old must be directories, and must not be on the
* same file system as the current process root. The put_old must be
* underneath new_root, i.e. adding a non-zero number of /.. to the string
* pointed to by put_old must yield the same directory as new_root. No other
* file system may be mounted on put_old. After all, new_root is a mountpoint.
*
* Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem.
* See Documentation/filesystems/ramfs-rootfs-initramfs.rst for alternatives
* in this situation.
*
* Notes:
* - we don't move root/cwd if they are not at the root (reason: if something
* cared enough to change them, it's probably wrong to force them elsewhere)
* - it's okay to pick a root that isn't the root of a file system, e.g.
* /nfs/my_root where /nfs is the mount point. It must be a mountpoint,
* though, so you may need to say mount --bind /nfs/my_root /nfs/my_root
* first.
*/
SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
const char __user *, put_old)
{
struct path new, old, root;
struct mount *new_mnt, *root_mnt, *old_mnt, *root_parent, *ex_parent;
struct mountpoint *old_mp, *root_mp;
int error;
if (!may_mount())
return -EPERM;
error = user_path_at(AT_FDCWD, new_root,
LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &new);
if (error)
goto out0;
error = user_path_at(AT_FDCWD, put_old,
LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old);
if (error)
goto out1;
error = security_sb_pivotroot(&old, &new);
if (error)
goto out2;
get_fs_root(current->fs, &root);
old_mp = lock_mount(&old);
error = PTR_ERR(old_mp);
if (IS_ERR(old_mp))
goto out3;
error = -EINVAL;
new_mnt = real_mount(new.mnt);
root_mnt = real_mount(root.mnt);
old_mnt = real_mount(old.mnt);
ex_parent = new_mnt->mnt_parent;
root_parent = root_mnt->mnt_parent;
if (IS_MNT_SHARED(old_mnt) ||
IS_MNT_SHARED(ex_parent) ||
IS_MNT_SHARED(root_parent))
goto out4;
if (!check_mnt(root_mnt) || !check_mnt(new_mnt))
goto out4;
if (new_mnt->mnt.mnt_flags & MNT_LOCKED)
goto out4;
error = -ENOENT;
if (d_unlinked(new.dentry))
goto out4;
error = -EBUSY;
if (new_mnt == root_mnt || old_mnt == root_mnt)
goto out4; /* loop, on the same file system */
error = -EINVAL;
if (!path_mounted(&root))
goto out4; /* not a mountpoint */
if (!mnt_has_parent(root_mnt))
goto out4; /* not attached */
if (!path_mounted(&new))
goto out4; /* not a mountpoint */
if (!mnt_has_parent(new_mnt))
goto out4; /* not attached */
/* make sure we can reach put_old from new_root */
if (!is_path_reachable(old_mnt, old.dentry, &new))
goto out4;
/* make certain new is below the root */
if (!is_path_reachable(new_mnt, new.dentry, &root))
goto out4;
lock_mount_hash();
umount_mnt(new_mnt);
root_mp = unhash_mnt(root_mnt); /* we'll need its mountpoint */
if (root_mnt->mnt.mnt_flags & MNT_LOCKED) {
new_mnt->mnt.mnt_flags |= MNT_LOCKED;
root_mnt->mnt.mnt_flags &= ~MNT_LOCKED;
}
/* mount old root on put_old */
attach_mnt(root_mnt, old_mnt, old_mp, false);
/* mount new_root on / */
attach_mnt(new_mnt, root_parent, root_mp, false);
mnt_add_count(root_parent, -1);
touch_mnt_namespace(current->nsproxy->mnt_ns);
/* A moved mount should not expire automatically */
list_del_init(&new_mnt->mnt_expire);
put_mountpoint(root_mp);
unlock_mount_hash();
chroot_fs_refs(&root, &new);
error = 0;
out4:
unlock_mount(old_mp);
if (!error)
mntput_no_expire(ex_parent);
out3:
path_put(&root);
out2:
path_put(&old);
out1:
path_put(&new);
out0:
return error;
}
static unsigned int recalc_flags(struct mount_kattr *kattr, struct mount *mnt)
{
unsigned int flags = mnt->mnt.mnt_flags;
/* flags to clear */
flags &= ~kattr->attr_clr;
/* flags to raise */
flags |= kattr->attr_set;
return flags;
}
static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt)
{
struct vfsmount *m = &mnt->mnt;
struct user_namespace *fs_userns = m->mnt_sb->s_user_ns;
if (!kattr->mnt_idmap)
return 0;
/*
* Creating an idmapped mount with the filesystem wide idmapping
* doesn't make sense so block that. We don't allow mushy semantics.
*/
if (!check_fsmapping(kattr->mnt_idmap, m->mnt_sb))
return -EINVAL;
/*
* Once a mount has been idmapped we don't allow it to change its
* mapping. It makes things simpler and callers can just create
* another bind-mount they can idmap if they want to.
*/
if (is_idmapped_mnt(m))
return -EPERM;
/* The underlying filesystem doesn't support idmapped mounts yet. */
if (!(m->mnt_sb->s_type->fs_flags & FS_ALLOW_IDMAP))
return -EINVAL;
/* We're not controlling the superblock. */
if (!ns_capable(fs_userns, CAP_SYS_ADMIN))
return -EPERM;
/* Mount has already been visible in the filesystem hierarchy. */
if (!is_anon_ns(mnt->mnt_ns))
return -EINVAL;
return 0;
}
/**
* mnt_allow_writers() - check whether the attribute change allows writers
* @kattr: the new mount attributes
* @mnt: the mount to which @kattr will be applied
*
* Check whether thew new mount attributes in @kattr allow concurrent writers.
*
* Return: true if writers need to be held, false if not
*/
static inline bool mnt_allow_writers(const struct mount_kattr *kattr,
const struct mount *mnt)
{
return (!(kattr->attr_set & MNT_READONLY) ||
(mnt->mnt.mnt_flags & MNT_READONLY)) &&
!kattr->mnt_idmap;
}
static int mount_setattr_prepare(struct mount_kattr *kattr, struct mount *mnt)
{
struct mount *m;
int err;
for (m = mnt; m; m = next_mnt(m, mnt)) {
if (!can_change_locked_flags(m, recalc_flags(kattr, m))) {
err = -EPERM;
break;
}
err = can_idmap_mount(kattr, m);
if (err)
break;
if (!mnt_allow_writers(kattr, m)) {
err = mnt_hold_writers(m);
if (err)
break;
}
if (!kattr->recurse)
return 0;
}
if (err) {
struct mount *p;
/*
* If we had to call mnt_hold_writers() MNT_WRITE_HOLD will
* be set in @mnt_flags. The loop unsets MNT_WRITE_HOLD for all
* mounts and needs to take care to include the first mount.
*/
for (p = mnt; p; p = next_mnt(p, mnt)) {
/* If we had to hold writers unblock them. */
if (p->mnt.mnt_flags & MNT_WRITE_HOLD)
mnt_unhold_writers(p);
/*
* We're done once the first mount we changed got
* MNT_WRITE_HOLD unset.
*/
if (p == m)
break;
}
}
return err;
}
static void do_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt)
{
if (!kattr->mnt_idmap)
return;
/*
* Pairs with smp_load_acquire() in mnt_idmap().
*
* Since we only allow a mount to change the idmapping once and
* verified this in can_idmap_mount() we know that the mount has
* @nop_mnt_idmap attached to it. So there's no need to drop any
* references.
*/
smp_store_release(&mnt->mnt.mnt_idmap, mnt_idmap_get(kattr->mnt_idmap));
}
static void mount_setattr_commit(struct mount_kattr *kattr, struct mount *mnt)
{
struct mount *m;
for (m = mnt; m; m = next_mnt(m, mnt)) {
unsigned int flags;
do_idmap_mount(kattr, m);
flags = recalc_flags(kattr, m);
WRITE_ONCE(m->mnt.mnt_flags, flags);
/* If we had to hold writers unblock them. */
if (m->mnt.mnt_flags & MNT_WRITE_HOLD)
mnt_unhold_writers(m);
if (kattr->propagation)
change_mnt_propagation(m, kattr->propagation);
if (!kattr->recurse)
break;
}
touch_mnt_namespace(mnt->mnt_ns);
}
static int do_mount_setattr(struct path *path, struct mount_kattr *kattr)
{
struct mount *mnt = real_mount(path->mnt);
int err = 0;
if (!path_mounted(path))
return -EINVAL;
if (kattr->mnt_userns) {
struct mnt_idmap *mnt_idmap;
mnt_idmap = alloc_mnt_idmap(kattr->mnt_userns);
if (IS_ERR(mnt_idmap))
return PTR_ERR(mnt_idmap);
kattr->mnt_idmap = mnt_idmap;
}
if (kattr->propagation) {
/*
* Only take namespace_lock() if we're actually changing
* propagation.
*/
namespace_lock();
if (kattr->propagation == MS_SHARED) {
err = invent_group_ids(mnt, kattr->recurse);
if (err) {
namespace_unlock();
return err;
}
}
}
err = -EINVAL;
lock_mount_hash();
/* Ensure that this isn't anything purely vfs internal. */
if (!is_mounted(&mnt->mnt))
goto out;
/*
* If this is an attached mount make sure it's located in the callers
* mount namespace. If it's not don't let the caller interact with it.
* If this is a detached mount make sure it has an anonymous mount
* namespace attached to it, i.e. we've created it via OPEN_TREE_CLONE.
*/
if (!(mnt_has_parent(mnt) ? check_mnt(mnt) : is_anon_ns(mnt->mnt_ns)))
goto out;
/*
* First, we get the mount tree in a shape where we can change mount
* properties without failure. If we succeeded to do so we commit all
* changes and if we failed we clean up.
*/
err = mount_setattr_prepare(kattr, mnt);
if (!err)
mount_setattr_commit(kattr, mnt);
out:
unlock_mount_hash();
if (kattr->propagation) {
if (err)
cleanup_group_ids(mnt, NULL);
namespace_unlock();
}
return err;
}
static int build_mount_idmapped(const struct mount_attr *attr, size_t usize,
struct mount_kattr *kattr, unsigned int flags)
{
int err = 0;
struct ns_common *ns;
struct user_namespace *mnt_userns;
struct fd f;
if (!((attr->attr_set | attr->attr_clr) & MOUNT_ATTR_IDMAP))
return 0;
/*
* We currently do not support clearing an idmapped mount. If this ever
* is a use-case we can revisit this but for now let's keep it simple
* and not allow it.
*/
if (attr->attr_clr & MOUNT_ATTR_IDMAP)
return -EINVAL;
if (attr->userns_fd > INT_MAX)
return -EINVAL;
f = fdget(attr->userns_fd);
if (!f.file)
return -EBADF;
if (!proc_ns_file(f.file)) {
err = -EINVAL;
goto out_fput;
}
ns = get_proc_ns(file_inode(f.file));
if (ns->ops->type != CLONE_NEWUSER) {
err = -EINVAL;
goto out_fput;
}
/*
* The initial idmapping cannot be used to create an idmapped
* mount. We use the initial idmapping as an indicator of a mount
* that is not idmapped. It can simply be passed into helpers that
* are aware of idmapped mounts as a convenient shortcut. A user
* can just create a dedicated identity mapping to achieve the same
* result.
*/
mnt_userns = container_of(ns, struct user_namespace, ns);
if (mnt_userns == &init_user_ns) {
err = -EPERM;
goto out_fput;
}
/* We're not controlling the target namespace. */
if (!ns_capable(mnt_userns, CAP_SYS_ADMIN)) {
err = -EPERM;
goto out_fput;
}
kattr->mnt_userns = get_user_ns(mnt_userns);
out_fput:
fdput(f);
return err;
}
static int build_mount_kattr(const struct mount_attr *attr, size_t usize,
struct mount_kattr *kattr, unsigned int flags)
{
unsigned int lookup_flags = LOOKUP_AUTOMOUNT | LOOKUP_FOLLOW;
if (flags & AT_NO_AUTOMOUNT)
lookup_flags &= ~LOOKUP_AUTOMOUNT;
if (flags & AT_SYMLINK_NOFOLLOW)
lookup_flags &= ~LOOKUP_FOLLOW;
if (flags & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
*kattr = (struct mount_kattr) {
.lookup_flags = lookup_flags,
.recurse = !!(flags & AT_RECURSIVE),
};
if (attr->propagation & ~MOUNT_SETATTR_PROPAGATION_FLAGS)
return -EINVAL;
if (hweight32(attr->propagation & MOUNT_SETATTR_PROPAGATION_FLAGS) > 1)
return -EINVAL;
kattr->propagation = attr->propagation;
if ((attr->attr_set | attr->attr_clr) & ~MOUNT_SETATTR_VALID_FLAGS)
return -EINVAL;
kattr->attr_set = attr_flags_to_mnt_flags(attr->attr_set);
kattr->attr_clr = attr_flags_to_mnt_flags(attr->attr_clr);
/*
* Since the MOUNT_ATTR_<atime> values are an enum, not a bitmap,
* users wanting to transition to a different atime setting cannot
* simply specify the atime setting in @attr_set, but must also
* specify MOUNT_ATTR__ATIME in the @attr_clr field.
* So ensure that MOUNT_ATTR__ATIME can't be partially set in
* @attr_clr and that @attr_set can't have any atime bits set if
* MOUNT_ATTR__ATIME isn't set in @attr_clr.
*/
if (attr->attr_clr & MOUNT_ATTR__ATIME) {
if ((attr->attr_clr & MOUNT_ATTR__ATIME) != MOUNT_ATTR__ATIME)
return -EINVAL;
/*
* Clear all previous time settings as they are mutually
* exclusive.
*/
kattr->attr_clr |= MNT_RELATIME | MNT_NOATIME;
switch (attr->attr_set & MOUNT_ATTR__ATIME) {
case MOUNT_ATTR_RELATIME:
kattr->attr_set |= MNT_RELATIME;
break;
case MOUNT_ATTR_NOATIME:
kattr->attr_set |= MNT_NOATIME;
break;
case MOUNT_ATTR_STRICTATIME:
break;
default:
return -EINVAL;
}
} else {
if (attr->attr_set & MOUNT_ATTR__ATIME)
return -EINVAL;
}
return build_mount_idmapped(attr, usize, kattr, flags);
}
static void finish_mount_kattr(struct mount_kattr *kattr)
{
put_user_ns(kattr->mnt_userns);
kattr->mnt_userns = NULL;
if (kattr->mnt_idmap)
mnt_idmap_put(kattr->mnt_idmap);
}
SYSCALL_DEFINE5(mount_setattr, int, dfd, const char __user *, path,
unsigned int, flags, struct mount_attr __user *, uattr,
size_t, usize)
{
int err;
struct path target;
struct mount_attr attr;
struct mount_kattr kattr;
BUILD_BUG_ON(sizeof(struct mount_attr) != MOUNT_ATTR_SIZE_VER0);
if (flags & ~(AT_EMPTY_PATH |
AT_RECURSIVE |
AT_SYMLINK_NOFOLLOW |
AT_NO_AUTOMOUNT))
return -EINVAL;
if (unlikely(usize > PAGE_SIZE))
return -E2BIG;
if (unlikely(usize < MOUNT_ATTR_SIZE_VER0))
return -EINVAL;
if (!may_mount())
return -EPERM;
err = copy_struct_from_user(&attr, sizeof(attr), uattr, usize);
if (err)
return err;
/* Don't bother walking through the mounts if this is a nop. */
if (attr.attr_set == 0 &&
attr.attr_clr == 0 &&
attr.propagation == 0)
return 0;
err = build_mount_kattr(&attr, usize, &kattr, flags);
if (err)
return err;
err = user_path_at(dfd, path, kattr.lookup_flags, &target);
if (!err) {
err = do_mount_setattr(&target, &kattr);
path_put(&target);
}
finish_mount_kattr(&kattr);
return err;
}
static void __init init_mount_tree(void)
{
struct vfsmount *mnt;
struct mount *m;
struct mnt_namespace *ns;
struct path root;
mnt = vfs_kern_mount(&rootfs_fs_type, 0, "rootfs", NULL);
if (IS_ERR(mnt))
panic("Can't create rootfs");
ns = alloc_mnt_ns(&init_user_ns, false);
if (IS_ERR(ns))
panic("Can't allocate initial namespace");
m = real_mount(mnt);
m->mnt_ns = ns;
ns->root = m;
ns->mounts = 1;
list_add(&m->mnt_list, &ns->list);
init_task.nsproxy->mnt_ns = ns;
get_mnt_ns(ns);
root.mnt = mnt;
root.dentry = mnt->mnt_root;
mnt->mnt_flags |= MNT_LOCKED;
set_fs_pwd(current->fs, &root);
set_fs_root(current->fs, &root);
}
void __init mnt_init(void)
{
int err;
mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount),
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL);
mount_hashtable = alloc_large_system_hash("Mount-cache",
sizeof(struct hlist_head),
mhash_entries, 19,
HASH_ZERO,
&m_hash_shift, &m_hash_mask, 0, 0);
mountpoint_hashtable = alloc_large_system_hash("Mountpoint-cache",
sizeof(struct hlist_head),
mphash_entries, 19,
HASH_ZERO,
&mp_hash_shift, &mp_hash_mask, 0, 0);
if (!mount_hashtable || !mountpoint_hashtable)
panic("Failed to allocate mount hash table\n");
kernfs_init();
err = sysfs_init();
if (err)
printk(KERN_WARNING "%s: sysfs_init error: %d\n",
__func__, err);
fs_kobj = kobject_create_and_add("fs", NULL);
if (!fs_kobj)
printk(KERN_WARNING "%s: kobj create error\n", __func__);
shmem_init();
init_rootfs();
init_mount_tree();
}
void put_mnt_ns(struct mnt_namespace *ns)
{
if (!refcount_dec_and_test(&ns->ns.count))
return;
drop_collected_mounts(&ns->root->mnt);
free_mnt_ns(ns);
}
struct vfsmount *kern_mount(struct file_system_type *type)
{
struct vfsmount *mnt;
mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL);
if (!IS_ERR(mnt)) {
/*
* it is a longterm mount, don't release mnt until
* we unmount before file sys is unregistered
*/
real_mount(mnt)->mnt_ns = MNT_NS_INTERNAL;
}
return mnt;
}
EXPORT_SYMBOL_GPL(kern_mount);
void kern_unmount(struct vfsmount *mnt)
{
/* release long term mount so mount point can be released */
if (!IS_ERR(mnt)) {
mnt_make_shortterm(mnt);
synchronize_rcu(); /* yecchhh... */
mntput(mnt);
}
}
EXPORT_SYMBOL(kern_unmount);
void kern_unmount_array(struct vfsmount *mnt[], unsigned int num)
{
unsigned int i;
for (i = 0; i < num; i++)
mnt_make_shortterm(mnt[i]);
synchronize_rcu_expedited();
for (i = 0; i < num; i++)
mntput(mnt[i]);
}
EXPORT_SYMBOL(kern_unmount_array);
bool our_mnt(struct vfsmount *mnt)
{
return check_mnt(real_mount(mnt));
}
bool current_chrooted(void)
{
/* Does the current process have a non-standard root */
struct path ns_root;
struct path fs_root;
bool chrooted;
/* Find the namespace root */
ns_root.mnt = ¤t->nsproxy->mnt_ns->root->mnt;
ns_root.dentry = ns_root.mnt->mnt_root;
path_get(&ns_root);
while (d_mountpoint(ns_root.dentry) && follow_down_one(&ns_root))
;
get_fs_root(current->fs, &fs_root);
chrooted = !path_equal(&fs_root, &ns_root);
path_put(&fs_root);
path_put(&ns_root);
return chrooted;
}
static bool mnt_already_visible(struct mnt_namespace *ns,
const struct super_block *sb,
int *new_mnt_flags)
{
int new_flags = *new_mnt_flags;
struct mount *mnt;
bool visible = false;
down_read(&namespace_sem);
lock_ns_list(ns);
list_for_each_entry(mnt, &ns->list, mnt_list) {
struct mount *child;
int mnt_flags;
if (mnt_is_cursor(mnt))
continue;
if (mnt->mnt.mnt_sb->s_type != sb->s_type)
continue;
/* This mount is not fully visible if it's root directory
* is not the root directory of the filesystem.
*/
if (mnt->mnt.mnt_root != mnt->mnt.mnt_sb->s_root)
continue;
/* A local view of the mount flags */
mnt_flags = mnt->mnt.mnt_flags;
/* Don't miss readonly hidden in the superblock flags */
if (sb_rdonly(mnt->mnt.mnt_sb))
mnt_flags |= MNT_LOCK_READONLY;
/* Verify the mount flags are equal to or more permissive
* than the proposed new mount.
*/
if ((mnt_flags & MNT_LOCK_READONLY) &&
!(new_flags & MNT_READONLY))
continue;
if ((mnt_flags & MNT_LOCK_ATIME) &&
((mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK)))
continue;
/* This mount is not fully visible if there are any
* locked child mounts that cover anything except for
* empty directories.
*/
list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
struct inode *inode = child->mnt_mountpoint->d_inode;
/* Only worry about locked mounts */
if (!(child->mnt.mnt_flags & MNT_LOCKED))
continue;
/* Is the directory permanetly empty? */
if (!is_empty_dir_inode(inode))
goto next;
}
/* Preserve the locked attributes */
*new_mnt_flags |= mnt_flags & (MNT_LOCK_READONLY | \
MNT_LOCK_ATIME);
visible = true;
goto found;
next: ;
}
found:
unlock_ns_list(ns);
up_read(&namespace_sem);
return visible;
}
static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags)
{
const unsigned long required_iflags = SB_I_NOEXEC | SB_I_NODEV;
struct mnt_namespace *ns = current->nsproxy->mnt_ns;
unsigned long s_iflags;
if (ns->user_ns == &init_user_ns)
return false;
/* Can this filesystem be too revealing? */
s_iflags = sb->s_iflags;
if (!(s_iflags & SB_I_USERNS_VISIBLE))
return false;
if ((s_iflags & required_iflags) != required_iflags) {
WARN_ONCE(1, "Expected s_iflags to contain 0x%lx\n",
required_iflags);
return true;
}
return !mnt_already_visible(ns, sb, new_mnt_flags);
}
bool mnt_may_suid(struct vfsmount *mnt)
{
/*
* Foreign mounts (accessed via fchdir or through /proc
* symlinks) are always treated as if they are nosuid. This
* prevents namespaces from trusting potentially unsafe
* suid/sgid bits, file caps, or security labels that originate
* in other namespaces.
*/
return !(mnt->mnt_flags & MNT_NOSUID) && check_mnt(real_mount(mnt)) &&
current_in_userns(mnt->mnt_sb->s_user_ns);
}
static struct ns_common *mntns_get(struct task_struct *task)
{
struct ns_common *ns = NULL;
struct nsproxy *nsproxy;
task_lock(task);
nsproxy = task->nsproxy;
if (nsproxy) {
ns = &nsproxy->mnt_ns->ns;
get_mnt_ns(to_mnt_ns(ns));
}
task_unlock(task);
return ns;
}
static void mntns_put(struct ns_common *ns)
{
put_mnt_ns(to_mnt_ns(ns));
}
static int mntns_install(struct nsset *nsset, struct ns_common *ns)
{
struct nsproxy *nsproxy = nsset->nsproxy;
struct fs_struct *fs = nsset->fs;
struct mnt_namespace *mnt_ns = to_mnt_ns(ns), *old_mnt_ns;
struct user_namespace *user_ns = nsset->cred->user_ns;
struct path root;
int err;
if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
!ns_capable(user_ns, CAP_SYS_CHROOT) ||
!ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (is_anon_ns(mnt_ns))
return -EINVAL;
if (fs->users != 1)
return -EINVAL;
get_mnt_ns(mnt_ns);
old_mnt_ns = nsproxy->mnt_ns;
nsproxy->mnt_ns = mnt_ns;
/* Find the root */
err = vfs_path_lookup(mnt_ns->root->mnt.mnt_root, &mnt_ns->root->mnt,
"/", LOOKUP_DOWN, &root);
if (err) {
/* revert to old namespace */
nsproxy->mnt_ns = old_mnt_ns;
put_mnt_ns(mnt_ns);
return err;
}
put_mnt_ns(old_mnt_ns);
/* Update the pwd and root */
set_fs_pwd(fs, &root);
set_fs_root(fs, &root);
path_put(&root);
return 0;
}
static struct user_namespace *mntns_owner(struct ns_common *ns)
{
return to_mnt_ns(ns)->user_ns;
}
const struct proc_ns_operations mntns_operations = {
.name = "mnt",
.type = CLONE_NEWNS,
.get = mntns_get,
.put = mntns_put,
.install = mntns_install,
.owner = mntns_owner,
};
#ifdef CONFIG_SYSCTL
static struct ctl_table fs_namespace_sysctls[] = {
{
.procname = "mount-max",
.data = &sysctl_mount_max,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
},
{ }
};
static int __init init_fs_namespace_sysctls(void)
{
register_sysctl_init("fs", fs_namespace_sysctls);
return 0;
}
fs_initcall(init_fs_namespace_sysctls);
#endif /* CONFIG_SYSCTL */
| linux-master | fs/namespace.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/char_dev.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/kdev_t.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/kobject.h>
#include <linux/kobj_map.h>
#include <linux/cdev.h>
#include <linux/mutex.h>
#include <linux/backing-dev.h>
#include <linux/tty.h>
#include "internal.h"
static struct kobj_map *cdev_map;
static DEFINE_MUTEX(chrdevs_lock);
#define CHRDEV_MAJOR_HASH_SIZE 255
static struct char_device_struct {
struct char_device_struct *next;
unsigned int major;
unsigned int baseminor;
int minorct;
char name[64];
struct cdev *cdev; /* will die */
} *chrdevs[CHRDEV_MAJOR_HASH_SIZE];
/* index in the above */
static inline int major_to_index(unsigned major)
{
return major % CHRDEV_MAJOR_HASH_SIZE;
}
#ifdef CONFIG_PROC_FS
void chrdev_show(struct seq_file *f, off_t offset)
{
struct char_device_struct *cd;
mutex_lock(&chrdevs_lock);
for (cd = chrdevs[major_to_index(offset)]; cd; cd = cd->next) {
if (cd->major == offset)
seq_printf(f, "%3d %s\n", cd->major, cd->name);
}
mutex_unlock(&chrdevs_lock);
}
#endif /* CONFIG_PROC_FS */
static int find_dynamic_major(void)
{
int i;
struct char_device_struct *cd;
for (i = ARRAY_SIZE(chrdevs)-1; i >= CHRDEV_MAJOR_DYN_END; i--) {
if (chrdevs[i] == NULL)
return i;
}
for (i = CHRDEV_MAJOR_DYN_EXT_START;
i >= CHRDEV_MAJOR_DYN_EXT_END; i--) {
for (cd = chrdevs[major_to_index(i)]; cd; cd = cd->next)
if (cd->major == i)
break;
if (cd == NULL)
return i;
}
return -EBUSY;
}
/*
* Register a single major with a specified minor range.
*
* If major == 0 this function will dynamically allocate an unused major.
* If major > 0 this function will attempt to reserve the range of minors
* with given major.
*
*/
static struct char_device_struct *
__register_chrdev_region(unsigned int major, unsigned int baseminor,
int minorct, const char *name)
{
struct char_device_struct *cd, *curr, *prev = NULL;
int ret;
int i;
if (major >= CHRDEV_MAJOR_MAX) {
pr_err("CHRDEV \"%s\" major requested (%u) is greater than the maximum (%u)\n",
name, major, CHRDEV_MAJOR_MAX-1);
return ERR_PTR(-EINVAL);
}
if (minorct > MINORMASK + 1 - baseminor) {
pr_err("CHRDEV \"%s\" minor range requested (%u-%u) is out of range of maximum range (%u-%u) for a single major\n",
name, baseminor, baseminor + minorct - 1, 0, MINORMASK);
return ERR_PTR(-EINVAL);
}
cd = kzalloc(sizeof(struct char_device_struct), GFP_KERNEL);
if (cd == NULL)
return ERR_PTR(-ENOMEM);
mutex_lock(&chrdevs_lock);
if (major == 0) {
ret = find_dynamic_major();
if (ret < 0) {
pr_err("CHRDEV \"%s\" dynamic allocation region is full\n",
name);
goto out;
}
major = ret;
}
ret = -EBUSY;
i = major_to_index(major);
for (curr = chrdevs[i]; curr; prev = curr, curr = curr->next) {
if (curr->major < major)
continue;
if (curr->major > major)
break;
if (curr->baseminor + curr->minorct <= baseminor)
continue;
if (curr->baseminor >= baseminor + minorct)
break;
goto out;
}
cd->major = major;
cd->baseminor = baseminor;
cd->minorct = minorct;
strscpy(cd->name, name, sizeof(cd->name));
if (!prev) {
cd->next = curr;
chrdevs[i] = cd;
} else {
cd->next = prev->next;
prev->next = cd;
}
mutex_unlock(&chrdevs_lock);
return cd;
out:
mutex_unlock(&chrdevs_lock);
kfree(cd);
return ERR_PTR(ret);
}
static struct char_device_struct *
__unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct)
{
struct char_device_struct *cd = NULL, **cp;
int i = major_to_index(major);
mutex_lock(&chrdevs_lock);
for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
if ((*cp)->major == major &&
(*cp)->baseminor == baseminor &&
(*cp)->minorct == minorct)
break;
if (*cp) {
cd = *cp;
*cp = cd->next;
}
mutex_unlock(&chrdevs_lock);
return cd;
}
/**
* register_chrdev_region() - register a range of device numbers
* @from: the first in the desired range of device numbers; must include
* the major number.
* @count: the number of consecutive device numbers required
* @name: the name of the device or driver.
*
* Return value is zero on success, a negative error code on failure.
*/
int register_chrdev_region(dev_t from, unsigned count, const char *name)
{
struct char_device_struct *cd;
dev_t to = from + count;
dev_t n, next;
for (n = from; n < to; n = next) {
next = MKDEV(MAJOR(n)+1, 0);
if (next > to)
next = to;
cd = __register_chrdev_region(MAJOR(n), MINOR(n),
next - n, name);
if (IS_ERR(cd))
goto fail;
}
return 0;
fail:
to = n;
for (n = from; n < to; n = next) {
next = MKDEV(MAJOR(n)+1, 0);
kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
}
return PTR_ERR(cd);
}
/**
* alloc_chrdev_region() - register a range of char device numbers
* @dev: output parameter for first assigned number
* @baseminor: first of the requested range of minor numbers
* @count: the number of minor numbers required
* @name: the name of the associated device or driver
*
* Allocates a range of char device numbers. The major number will be
* chosen dynamically, and returned (along with the first minor number)
* in @dev. Returns zero or a negative error code.
*/
int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
const char *name)
{
struct char_device_struct *cd;
cd = __register_chrdev_region(0, baseminor, count, name);
if (IS_ERR(cd))
return PTR_ERR(cd);
*dev = MKDEV(cd->major, cd->baseminor);
return 0;
}
/**
* __register_chrdev() - create and register a cdev occupying a range of minors
* @major: major device number or 0 for dynamic allocation
* @baseminor: first of the requested range of minor numbers
* @count: the number of minor numbers required
* @name: name of this range of devices
* @fops: file operations associated with this devices
*
* If @major == 0 this functions will dynamically allocate a major and return
* its number.
*
* If @major > 0 this function will attempt to reserve a device with the given
* major number and will return zero on success.
*
* Returns a -ve errno on failure.
*
* The name of this device has nothing to do with the name of the device in
* /dev. It only helps to keep track of the different owners of devices. If
* your module name has only one type of devices it's ok to use e.g. the name
* of the module here.
*/
int __register_chrdev(unsigned int major, unsigned int baseminor,
unsigned int count, const char *name,
const struct file_operations *fops)
{
struct char_device_struct *cd;
struct cdev *cdev;
int err = -ENOMEM;
cd = __register_chrdev_region(major, baseminor, count, name);
if (IS_ERR(cd))
return PTR_ERR(cd);
cdev = cdev_alloc();
if (!cdev)
goto out2;
cdev->owner = fops->owner;
cdev->ops = fops;
kobject_set_name(&cdev->kobj, "%s", name);
err = cdev_add(cdev, MKDEV(cd->major, baseminor), count);
if (err)
goto out;
cd->cdev = cdev;
return major ? 0 : cd->major;
out:
kobject_put(&cdev->kobj);
out2:
kfree(__unregister_chrdev_region(cd->major, baseminor, count));
return err;
}
/**
* unregister_chrdev_region() - unregister a range of device numbers
* @from: the first in the range of numbers to unregister
* @count: the number of device numbers to unregister
*
* This function will unregister a range of @count device numbers,
* starting with @from. The caller should normally be the one who
* allocated those numbers in the first place...
*/
void unregister_chrdev_region(dev_t from, unsigned count)
{
dev_t to = from + count;
dev_t n, next;
for (n = from; n < to; n = next) {
next = MKDEV(MAJOR(n)+1, 0);
if (next > to)
next = to;
kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));
}
}
/**
* __unregister_chrdev - unregister and destroy a cdev
* @major: major device number
* @baseminor: first of the range of minor numbers
* @count: the number of minor numbers this cdev is occupying
* @name: name of this range of devices
*
* Unregister and destroy the cdev occupying the region described by
* @major, @baseminor and @count. This function undoes what
* __register_chrdev() did.
*/
void __unregister_chrdev(unsigned int major, unsigned int baseminor,
unsigned int count, const char *name)
{
struct char_device_struct *cd;
cd = __unregister_chrdev_region(major, baseminor, count);
if (cd && cd->cdev)
cdev_del(cd->cdev);
kfree(cd);
}
static DEFINE_SPINLOCK(cdev_lock);
static struct kobject *cdev_get(struct cdev *p)
{
struct module *owner = p->owner;
struct kobject *kobj;
if (owner && !try_module_get(owner))
return NULL;
kobj = kobject_get_unless_zero(&p->kobj);
if (!kobj)
module_put(owner);
return kobj;
}
void cdev_put(struct cdev *p)
{
if (p) {
struct module *owner = p->owner;
kobject_put(&p->kobj);
module_put(owner);
}
}
/*
* Called every time a character special file is opened
*/
static int chrdev_open(struct inode *inode, struct file *filp)
{
const struct file_operations *fops;
struct cdev *p;
struct cdev *new = NULL;
int ret = 0;
spin_lock(&cdev_lock);
p = inode->i_cdev;
if (!p) {
struct kobject *kobj;
int idx;
spin_unlock(&cdev_lock);
kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx);
if (!kobj)
return -ENXIO;
new = container_of(kobj, struct cdev, kobj);
spin_lock(&cdev_lock);
/* Check i_cdev again in case somebody beat us to it while
we dropped the lock. */
p = inode->i_cdev;
if (!p) {
inode->i_cdev = p = new;
list_add(&inode->i_devices, &p->list);
new = NULL;
} else if (!cdev_get(p))
ret = -ENXIO;
} else if (!cdev_get(p))
ret = -ENXIO;
spin_unlock(&cdev_lock);
cdev_put(new);
if (ret)
return ret;
ret = -ENXIO;
fops = fops_get(p->ops);
if (!fops)
goto out_cdev_put;
replace_fops(filp, fops);
if (filp->f_op->open) {
ret = filp->f_op->open(inode, filp);
if (ret)
goto out_cdev_put;
}
return 0;
out_cdev_put:
cdev_put(p);
return ret;
}
void cd_forget(struct inode *inode)
{
spin_lock(&cdev_lock);
list_del_init(&inode->i_devices);
inode->i_cdev = NULL;
inode->i_mapping = &inode->i_data;
spin_unlock(&cdev_lock);
}
static void cdev_purge(struct cdev *cdev)
{
spin_lock(&cdev_lock);
while (!list_empty(&cdev->list)) {
struct inode *inode;
inode = container_of(cdev->list.next, struct inode, i_devices);
list_del_init(&inode->i_devices);
inode->i_cdev = NULL;
}
spin_unlock(&cdev_lock);
}
/*
* Dummy default file-operations: the only thing this does
* is contain the open that then fills in the correct operations
* depending on the special file...
*/
const struct file_operations def_chr_fops = {
.open = chrdev_open,
.llseek = noop_llseek,
};
static struct kobject *exact_match(dev_t dev, int *part, void *data)
{
struct cdev *p = data;
return &p->kobj;
}
static int exact_lock(dev_t dev, void *data)
{
struct cdev *p = data;
return cdev_get(p) ? 0 : -1;
}
/**
* cdev_add() - add a char device to the system
* @p: the cdev structure for the device
* @dev: the first device number for which this device is responsible
* @count: the number of consecutive minor numbers corresponding to this
* device
*
* cdev_add() adds the device represented by @p to the system, making it
* live immediately. A negative error code is returned on failure.
*/
int cdev_add(struct cdev *p, dev_t dev, unsigned count)
{
int error;
p->dev = dev;
p->count = count;
if (WARN_ON(dev == WHITEOUT_DEV)) {
error = -EBUSY;
goto err;
}
error = kobj_map(cdev_map, dev, count, NULL,
exact_match, exact_lock, p);
if (error)
goto err;
kobject_get(p->kobj.parent);
return 0;
err:
kfree_const(p->kobj.name);
p->kobj.name = NULL;
return error;
}
/**
* cdev_set_parent() - set the parent kobject for a char device
* @p: the cdev structure
* @kobj: the kobject to take a reference to
*
* cdev_set_parent() sets a parent kobject which will be referenced
* appropriately so the parent is not freed before the cdev. This
* should be called before cdev_add.
*/
void cdev_set_parent(struct cdev *p, struct kobject *kobj)
{
WARN_ON(!kobj->state_initialized);
p->kobj.parent = kobj;
}
/**
* cdev_device_add() - add a char device and it's corresponding
* struct device, linkink
* @dev: the device structure
* @cdev: the cdev structure
*
* cdev_device_add() adds the char device represented by @cdev to the system,
* just as cdev_add does. It then adds @dev to the system using device_add
* The dev_t for the char device will be taken from the struct device which
* needs to be initialized first. This helper function correctly takes a
* reference to the parent device so the parent will not get released until
* all references to the cdev are released.
*
* This helper uses dev->devt for the device number. If it is not set
* it will not add the cdev and it will be equivalent to device_add.
*
* This function should be used whenever the struct cdev and the
* struct device are members of the same structure whose lifetime is
* managed by the struct device.
*
* NOTE: Callers must assume that userspace was able to open the cdev and
* can call cdev fops callbacks at any time, even if this function fails.
*/
int cdev_device_add(struct cdev *cdev, struct device *dev)
{
int rc = 0;
if (dev->devt) {
cdev_set_parent(cdev, &dev->kobj);
rc = cdev_add(cdev, dev->devt, 1);
if (rc)
return rc;
}
rc = device_add(dev);
if (rc && dev->devt)
cdev_del(cdev);
return rc;
}
/**
* cdev_device_del() - inverse of cdev_device_add
* @dev: the device structure
* @cdev: the cdev structure
*
* cdev_device_del() is a helper function to call cdev_del and device_del.
* It should be used whenever cdev_device_add is used.
*
* If dev->devt is not set it will not remove the cdev and will be equivalent
* to device_del.
*
* NOTE: This guarantees that associated sysfs callbacks are not running
* or runnable, however any cdevs already open will remain and their fops
* will still be callable even after this function returns.
*/
void cdev_device_del(struct cdev *cdev, struct device *dev)
{
device_del(dev);
if (dev->devt)
cdev_del(cdev);
}
static void cdev_unmap(dev_t dev, unsigned count)
{
kobj_unmap(cdev_map, dev, count);
}
/**
* cdev_del() - remove a cdev from the system
* @p: the cdev structure to be removed
*
* cdev_del() removes @p from the system, possibly freeing the structure
* itself.
*
* NOTE: This guarantees that cdev device will no longer be able to be
* opened, however any cdevs already open will remain and their fops will
* still be callable even after cdev_del returns.
*/
void cdev_del(struct cdev *p)
{
cdev_unmap(p->dev, p->count);
kobject_put(&p->kobj);
}
static void cdev_default_release(struct kobject *kobj)
{
struct cdev *p = container_of(kobj, struct cdev, kobj);
struct kobject *parent = kobj->parent;
cdev_purge(p);
kobject_put(parent);
}
static void cdev_dynamic_release(struct kobject *kobj)
{
struct cdev *p = container_of(kobj, struct cdev, kobj);
struct kobject *parent = kobj->parent;
cdev_purge(p);
kfree(p);
kobject_put(parent);
}
static struct kobj_type ktype_cdev_default = {
.release = cdev_default_release,
};
static struct kobj_type ktype_cdev_dynamic = {
.release = cdev_dynamic_release,
};
/**
* cdev_alloc() - allocate a cdev structure
*
* Allocates and returns a cdev structure, or NULL on failure.
*/
struct cdev *cdev_alloc(void)
{
struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL);
if (p) {
INIT_LIST_HEAD(&p->list);
kobject_init(&p->kobj, &ktype_cdev_dynamic);
}
return p;
}
/**
* cdev_init() - initialize a cdev structure
* @cdev: the structure to initialize
* @fops: the file_operations for this device
*
* Initializes @cdev, remembering @fops, making it ready to add to the
* system with cdev_add().
*/
void cdev_init(struct cdev *cdev, const struct file_operations *fops)
{
memset(cdev, 0, sizeof *cdev);
INIT_LIST_HEAD(&cdev->list);
kobject_init(&cdev->kobj, &ktype_cdev_default);
cdev->ops = fops;
}
static struct kobject *base_probe(dev_t dev, int *part, void *data)
{
if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
/* Make old-style 2.4 aliases work */
request_module("char-major-%d", MAJOR(dev));
return NULL;
}
void __init chrdev_init(void)
{
cdev_map = kobj_map_init(base_probe, &chrdevs_lock);
}
/* Let modules do char dev stuff */
EXPORT_SYMBOL(register_chrdev_region);
EXPORT_SYMBOL(unregister_chrdev_region);
EXPORT_SYMBOL(alloc_chrdev_region);
EXPORT_SYMBOL(cdev_init);
EXPORT_SYMBOL(cdev_alloc);
EXPORT_SYMBOL(cdev_del);
EXPORT_SYMBOL(cdev_add);
EXPORT_SYMBOL(cdev_set_parent);
EXPORT_SYMBOL(cdev_device_add);
EXPORT_SYMBOL(cdev_device_del);
EXPORT_SYMBOL(__register_chrdev);
EXPORT_SYMBOL(__unregister_chrdev);
| linux-master | fs/char_dev.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/fs-writeback.c
*
* Copyright (C) 2002, Linus Torvalds.
*
* Contains all the functions related to writing back and waiting
* upon dirty inodes against superblocks, and writing back dirty
* pages against inodes. ie: data writeback. Writeout of the
* inode itself is not handled here.
*
* 10Apr2002 Andrew Morton
* Split out of fs/inode.c
* Additions for address_space-based writeback
*/
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/kthread.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/tracepoint.h>
#include <linux/device.h>
#include <linux/memcontrol.h>
#include "internal.h"
/*
* 4MB minimal write chunk size
*/
#define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_SHIFT - 10))
/*
* Passed into wb_writeback(), essentially a subset of writeback_control
*/
struct wb_writeback_work {
long nr_pages;
struct super_block *sb;
enum writeback_sync_modes sync_mode;
unsigned int tagged_writepages:1;
unsigned int for_kupdate:1;
unsigned int range_cyclic:1;
unsigned int for_background:1;
unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */
unsigned int auto_free:1; /* free on completion */
enum wb_reason reason; /* why was writeback initiated? */
struct list_head list; /* pending work list */
struct wb_completion *done; /* set if the caller waits */
};
/*
* If an inode is constantly having its pages dirtied, but then the
* updates stop dirtytime_expire_interval seconds in the past, it's
* possible for the worst case time between when an inode has its
* timestamps updated and when they finally get written out to be two
* dirtytime_expire_intervals. We set the default to 12 hours (in
* seconds), which means most of the time inodes will have their
* timestamps written to disk after 12 hours, but in the worst case a
* few inodes might not their timestamps updated for 24 hours.
*/
unsigned int dirtytime_expire_interval = 12 * 60 * 60;
static inline struct inode *wb_inode(struct list_head *head)
{
return list_entry(head, struct inode, i_io_list);
}
/*
* Include the creation of the trace points after defining the
* wb_writeback_work structure and inline functions so that the definition
* remains local to this file.
*/
#define CREATE_TRACE_POINTS
#include <trace/events/writeback.h>
EXPORT_TRACEPOINT_SYMBOL_GPL(wbc_writepage);
static bool wb_io_lists_populated(struct bdi_writeback *wb)
{
if (wb_has_dirty_io(wb)) {
return false;
} else {
set_bit(WB_has_dirty_io, &wb->state);
WARN_ON_ONCE(!wb->avg_write_bandwidth);
atomic_long_add(wb->avg_write_bandwidth,
&wb->bdi->tot_write_bandwidth);
return true;
}
}
static void wb_io_lists_depopulated(struct bdi_writeback *wb)
{
if (wb_has_dirty_io(wb) && list_empty(&wb->b_dirty) &&
list_empty(&wb->b_io) && list_empty(&wb->b_more_io)) {
clear_bit(WB_has_dirty_io, &wb->state);
WARN_ON_ONCE(atomic_long_sub_return(wb->avg_write_bandwidth,
&wb->bdi->tot_write_bandwidth) < 0);
}
}
/**
* inode_io_list_move_locked - move an inode onto a bdi_writeback IO list
* @inode: inode to be moved
* @wb: target bdi_writeback
* @head: one of @wb->b_{dirty|io|more_io|dirty_time}
*
* Move @inode->i_io_list to @list of @wb and set %WB_has_dirty_io.
* Returns %true if @inode is the first occupant of the !dirty_time IO
* lists; otherwise, %false.
*/
static bool inode_io_list_move_locked(struct inode *inode,
struct bdi_writeback *wb,
struct list_head *head)
{
assert_spin_locked(&wb->list_lock);
assert_spin_locked(&inode->i_lock);
WARN_ON_ONCE(inode->i_state & I_FREEING);
list_move(&inode->i_io_list, head);
/* dirty_time doesn't count as dirty_io until expiration */
if (head != &wb->b_dirty_time)
return wb_io_lists_populated(wb);
wb_io_lists_depopulated(wb);
return false;
}
static void wb_wakeup(struct bdi_writeback *wb)
{
spin_lock_irq(&wb->work_lock);
if (test_bit(WB_registered, &wb->state))
mod_delayed_work(bdi_wq, &wb->dwork, 0);
spin_unlock_irq(&wb->work_lock);
}
static void finish_writeback_work(struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
struct wb_completion *done = work->done;
if (work->auto_free)
kfree(work);
if (done) {
wait_queue_head_t *waitq = done->waitq;
/* @done can't be accessed after the following dec */
if (atomic_dec_and_test(&done->cnt))
wake_up_all(waitq);
}
}
static void wb_queue_work(struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
trace_writeback_queue(wb, work);
if (work->done)
atomic_inc(&work->done->cnt);
spin_lock_irq(&wb->work_lock);
if (test_bit(WB_registered, &wb->state)) {
list_add_tail(&work->list, &wb->work_list);
mod_delayed_work(bdi_wq, &wb->dwork, 0);
} else
finish_writeback_work(wb, work);
spin_unlock_irq(&wb->work_lock);
}
/**
* wb_wait_for_completion - wait for completion of bdi_writeback_works
* @done: target wb_completion
*
* Wait for one or more work items issued to @bdi with their ->done field
* set to @done, which should have been initialized with
* DEFINE_WB_COMPLETION(). This function returns after all such work items
* are completed. Work items which are waited upon aren't freed
* automatically on completion.
*/
void wb_wait_for_completion(struct wb_completion *done)
{
atomic_dec(&done->cnt); /* put down the initial count */
wait_event(*done->waitq, !atomic_read(&done->cnt));
}
#ifdef CONFIG_CGROUP_WRITEBACK
/*
* Parameters for foreign inode detection, see wbc_detach_inode() to see
* how they're used.
*
* These paramters are inherently heuristical as the detection target
* itself is fuzzy. All we want to do is detaching an inode from the
* current owner if it's being written to by some other cgroups too much.
*
* The current cgroup writeback is built on the assumption that multiple
* cgroups writing to the same inode concurrently is very rare and a mode
* of operation which isn't well supported. As such, the goal is not
* taking too long when a different cgroup takes over an inode while
* avoiding too aggressive flip-flops from occasional foreign writes.
*
* We record, very roughly, 2s worth of IO time history and if more than
* half of that is foreign, trigger the switch. The recording is quantized
* to 16 slots. To avoid tiny writes from swinging the decision too much,
* writes smaller than 1/8 of avg size are ignored.
*/
#define WB_FRN_TIME_SHIFT 13 /* 1s = 2^13, upto 8 secs w/ 16bit */
#define WB_FRN_TIME_AVG_SHIFT 3 /* avg = avg * 7/8 + new * 1/8 */
#define WB_FRN_TIME_CUT_DIV 8 /* ignore rounds < avg / 8 */
#define WB_FRN_TIME_PERIOD (2 * (1 << WB_FRN_TIME_SHIFT)) /* 2s */
#define WB_FRN_HIST_SLOTS 16 /* inode->i_wb_frn_history is 16bit */
#define WB_FRN_HIST_UNIT (WB_FRN_TIME_PERIOD / WB_FRN_HIST_SLOTS)
/* each slot's duration is 2s / 16 */
#define WB_FRN_HIST_THR_SLOTS (WB_FRN_HIST_SLOTS / 2)
/* if foreign slots >= 8, switch */
#define WB_FRN_HIST_MAX_SLOTS (WB_FRN_HIST_THR_SLOTS / 2 + 1)
/* one round can affect upto 5 slots */
#define WB_FRN_MAX_IN_FLIGHT 1024 /* don't queue too many concurrently */
/*
* Maximum inodes per isw. A specific value has been chosen to make
* struct inode_switch_wbs_context fit into 1024 bytes kmalloc.
*/
#define WB_MAX_INODES_PER_ISW ((1024UL - sizeof(struct inode_switch_wbs_context)) \
/ sizeof(struct inode *))
static atomic_t isw_nr_in_flight = ATOMIC_INIT(0);
static struct workqueue_struct *isw_wq;
void __inode_attach_wb(struct inode *inode, struct folio *folio)
{
struct backing_dev_info *bdi = inode_to_bdi(inode);
struct bdi_writeback *wb = NULL;
if (inode_cgwb_enabled(inode)) {
struct cgroup_subsys_state *memcg_css;
if (folio) {
memcg_css = mem_cgroup_css_from_folio(folio);
wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
} else {
/* must pin memcg_css, see wb_get_create() */
memcg_css = task_get_css(current, memory_cgrp_id);
wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
css_put(memcg_css);
}
}
if (!wb)
wb = &bdi->wb;
/*
* There may be multiple instances of this function racing to
* update the same inode. Use cmpxchg() to tell the winner.
*/
if (unlikely(cmpxchg(&inode->i_wb, NULL, wb)))
wb_put(wb);
}
EXPORT_SYMBOL_GPL(__inode_attach_wb);
/**
* inode_cgwb_move_to_attached - put the inode onto wb->b_attached list
* @inode: inode of interest with i_lock held
* @wb: target bdi_writeback
*
* Remove the inode from wb's io lists and if necessarily put onto b_attached
* list. Only inodes attached to cgwb's are kept on this list.
*/
static void inode_cgwb_move_to_attached(struct inode *inode,
struct bdi_writeback *wb)
{
assert_spin_locked(&wb->list_lock);
assert_spin_locked(&inode->i_lock);
WARN_ON_ONCE(inode->i_state & I_FREEING);
inode->i_state &= ~I_SYNC_QUEUED;
if (wb != &wb->bdi->wb)
list_move(&inode->i_io_list, &wb->b_attached);
else
list_del_init(&inode->i_io_list);
wb_io_lists_depopulated(wb);
}
/**
* locked_inode_to_wb_and_lock_list - determine a locked inode's wb and lock it
* @inode: inode of interest with i_lock held
*
* Returns @inode's wb with its list_lock held. @inode->i_lock must be
* held on entry and is released on return. The returned wb is guaranteed
* to stay @inode's associated wb until its list_lock is released.
*/
static struct bdi_writeback *
locked_inode_to_wb_and_lock_list(struct inode *inode)
__releases(&inode->i_lock)
__acquires(&wb->list_lock)
{
while (true) {
struct bdi_writeback *wb = inode_to_wb(inode);
/*
* inode_to_wb() association is protected by both
* @inode->i_lock and @wb->list_lock but list_lock nests
* outside i_lock. Drop i_lock and verify that the
* association hasn't changed after acquiring list_lock.
*/
wb_get(wb);
spin_unlock(&inode->i_lock);
spin_lock(&wb->list_lock);
/* i_wb may have changed inbetween, can't use inode_to_wb() */
if (likely(wb == inode->i_wb)) {
wb_put(wb); /* @inode already has ref */
return wb;
}
spin_unlock(&wb->list_lock);
wb_put(wb);
cpu_relax();
spin_lock(&inode->i_lock);
}
}
/**
* inode_to_wb_and_lock_list - determine an inode's wb and lock it
* @inode: inode of interest
*
* Same as locked_inode_to_wb_and_lock_list() but @inode->i_lock isn't held
* on entry.
*/
static struct bdi_writeback *inode_to_wb_and_lock_list(struct inode *inode)
__acquires(&wb->list_lock)
{
spin_lock(&inode->i_lock);
return locked_inode_to_wb_and_lock_list(inode);
}
struct inode_switch_wbs_context {
struct rcu_work work;
/*
* Multiple inodes can be switched at once. The switching procedure
* consists of two parts, separated by a RCU grace period. To make
* sure that the second part is executed for each inode gone through
* the first part, all inode pointers are placed into a NULL-terminated
* array embedded into struct inode_switch_wbs_context. Otherwise
* an inode could be left in a non-consistent state.
*/
struct bdi_writeback *new_wb;
struct inode *inodes[];
};
static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi)
{
down_write(&bdi->wb_switch_rwsem);
}
static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi)
{
up_write(&bdi->wb_switch_rwsem);
}
static bool inode_do_switch_wbs(struct inode *inode,
struct bdi_writeback *old_wb,
struct bdi_writeback *new_wb)
{
struct address_space *mapping = inode->i_mapping;
XA_STATE(xas, &mapping->i_pages, 0);
struct folio *folio;
bool switched = false;
spin_lock(&inode->i_lock);
xa_lock_irq(&mapping->i_pages);
/*
* Once I_FREEING or I_WILL_FREE are visible under i_lock, the eviction
* path owns the inode and we shouldn't modify ->i_io_list.
*/
if (unlikely(inode->i_state & (I_FREEING | I_WILL_FREE)))
goto skip_switch;
trace_inode_switch_wbs(inode, old_wb, new_wb);
/*
* Count and transfer stats. Note that PAGECACHE_TAG_DIRTY points
* to possibly dirty folios while PAGECACHE_TAG_WRITEBACK points to
* folios actually under writeback.
*/
xas_for_each_marked(&xas, folio, ULONG_MAX, PAGECACHE_TAG_DIRTY) {
if (folio_test_dirty(folio)) {
long nr = folio_nr_pages(folio);
wb_stat_mod(old_wb, WB_RECLAIMABLE, -nr);
wb_stat_mod(new_wb, WB_RECLAIMABLE, nr);
}
}
xas_set(&xas, 0);
xas_for_each_marked(&xas, folio, ULONG_MAX, PAGECACHE_TAG_WRITEBACK) {
long nr = folio_nr_pages(folio);
WARN_ON_ONCE(!folio_test_writeback(folio));
wb_stat_mod(old_wb, WB_WRITEBACK, -nr);
wb_stat_mod(new_wb, WB_WRITEBACK, nr);
}
if (mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) {
atomic_dec(&old_wb->writeback_inodes);
atomic_inc(&new_wb->writeback_inodes);
}
wb_get(new_wb);
/*
* Transfer to @new_wb's IO list if necessary. If the @inode is dirty,
* the specific list @inode was on is ignored and the @inode is put on
* ->b_dirty which is always correct including from ->b_dirty_time.
* The transfer preserves @inode->dirtied_when ordering. If the @inode
* was clean, it means it was on the b_attached list, so move it onto
* the b_attached list of @new_wb.
*/
if (!list_empty(&inode->i_io_list)) {
inode->i_wb = new_wb;
if (inode->i_state & I_DIRTY_ALL) {
struct inode *pos;
list_for_each_entry(pos, &new_wb->b_dirty, i_io_list)
if (time_after_eq(inode->dirtied_when,
pos->dirtied_when))
break;
inode_io_list_move_locked(inode, new_wb,
pos->i_io_list.prev);
} else {
inode_cgwb_move_to_attached(inode, new_wb);
}
} else {
inode->i_wb = new_wb;
}
/* ->i_wb_frn updates may race wbc_detach_inode() but doesn't matter */
inode->i_wb_frn_winner = 0;
inode->i_wb_frn_avg_time = 0;
inode->i_wb_frn_history = 0;
switched = true;
skip_switch:
/*
* Paired with load_acquire in unlocked_inode_to_wb_begin() and
* ensures that the new wb is visible if they see !I_WB_SWITCH.
*/
smp_store_release(&inode->i_state, inode->i_state & ~I_WB_SWITCH);
xa_unlock_irq(&mapping->i_pages);
spin_unlock(&inode->i_lock);
return switched;
}
static void inode_switch_wbs_work_fn(struct work_struct *work)
{
struct inode_switch_wbs_context *isw =
container_of(to_rcu_work(work), struct inode_switch_wbs_context, work);
struct backing_dev_info *bdi = inode_to_bdi(isw->inodes[0]);
struct bdi_writeback *old_wb = isw->inodes[0]->i_wb;
struct bdi_writeback *new_wb = isw->new_wb;
unsigned long nr_switched = 0;
struct inode **inodep;
/*
* If @inode switches cgwb membership while sync_inodes_sb() is
* being issued, sync_inodes_sb() might miss it. Synchronize.
*/
down_read(&bdi->wb_switch_rwsem);
/*
* By the time control reaches here, RCU grace period has passed
* since I_WB_SWITCH assertion and all wb stat update transactions
* between unlocked_inode_to_wb_begin/end() are guaranteed to be
* synchronizing against the i_pages lock.
*
* Grabbing old_wb->list_lock, inode->i_lock and the i_pages lock
* gives us exclusion against all wb related operations on @inode
* including IO list manipulations and stat updates.
*/
if (old_wb < new_wb) {
spin_lock(&old_wb->list_lock);
spin_lock_nested(&new_wb->list_lock, SINGLE_DEPTH_NESTING);
} else {
spin_lock(&new_wb->list_lock);
spin_lock_nested(&old_wb->list_lock, SINGLE_DEPTH_NESTING);
}
for (inodep = isw->inodes; *inodep; inodep++) {
WARN_ON_ONCE((*inodep)->i_wb != old_wb);
if (inode_do_switch_wbs(*inodep, old_wb, new_wb))
nr_switched++;
}
spin_unlock(&new_wb->list_lock);
spin_unlock(&old_wb->list_lock);
up_read(&bdi->wb_switch_rwsem);
if (nr_switched) {
wb_wakeup(new_wb);
wb_put_many(old_wb, nr_switched);
}
for (inodep = isw->inodes; *inodep; inodep++)
iput(*inodep);
wb_put(new_wb);
kfree(isw);
atomic_dec(&isw_nr_in_flight);
}
static bool inode_prepare_wbs_switch(struct inode *inode,
struct bdi_writeback *new_wb)
{
/*
* Paired with smp_mb() in cgroup_writeback_umount().
* isw_nr_in_flight must be increased before checking SB_ACTIVE and
* grabbing an inode, otherwise isw_nr_in_flight can be observed as 0
* in cgroup_writeback_umount() and the isw_wq will be not flushed.
*/
smp_mb();
if (IS_DAX(inode))
return false;
/* while holding I_WB_SWITCH, no one else can update the association */
spin_lock(&inode->i_lock);
if (!(inode->i_sb->s_flags & SB_ACTIVE) ||
inode->i_state & (I_WB_SWITCH | I_FREEING | I_WILL_FREE) ||
inode_to_wb(inode) == new_wb) {
spin_unlock(&inode->i_lock);
return false;
}
inode->i_state |= I_WB_SWITCH;
__iget(inode);
spin_unlock(&inode->i_lock);
return true;
}
/**
* inode_switch_wbs - change the wb association of an inode
* @inode: target inode
* @new_wb_id: ID of the new wb
*
* Switch @inode's wb association to the wb identified by @new_wb_id. The
* switching is performed asynchronously and may fail silently.
*/
static void inode_switch_wbs(struct inode *inode, int new_wb_id)
{
struct backing_dev_info *bdi = inode_to_bdi(inode);
struct cgroup_subsys_state *memcg_css;
struct inode_switch_wbs_context *isw;
/* noop if seems to be already in progress */
if (inode->i_state & I_WB_SWITCH)
return;
/* avoid queueing a new switch if too many are already in flight */
if (atomic_read(&isw_nr_in_flight) > WB_FRN_MAX_IN_FLIGHT)
return;
isw = kzalloc(struct_size(isw, inodes, 2), GFP_ATOMIC);
if (!isw)
return;
atomic_inc(&isw_nr_in_flight);
/* find and pin the new wb */
rcu_read_lock();
memcg_css = css_from_id(new_wb_id, &memory_cgrp_subsys);
if (memcg_css && !css_tryget(memcg_css))
memcg_css = NULL;
rcu_read_unlock();
if (!memcg_css)
goto out_free;
isw->new_wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
css_put(memcg_css);
if (!isw->new_wb)
goto out_free;
if (!inode_prepare_wbs_switch(inode, isw->new_wb))
goto out_free;
isw->inodes[0] = inode;
/*
* In addition to synchronizing among switchers, I_WB_SWITCH tells
* the RCU protected stat update paths to grab the i_page
* lock so that stat transfer can synchronize against them.
* Let's continue after I_WB_SWITCH is guaranteed to be visible.
*/
INIT_RCU_WORK(&isw->work, inode_switch_wbs_work_fn);
queue_rcu_work(isw_wq, &isw->work);
return;
out_free:
atomic_dec(&isw_nr_in_flight);
if (isw->new_wb)
wb_put(isw->new_wb);
kfree(isw);
}
/**
* cleanup_offline_cgwb - detach associated inodes
* @wb: target wb
*
* Switch all inodes attached to @wb to a nearest living ancestor's wb in order
* to eventually release the dying @wb. Returns %true if not all inodes were
* switched and the function has to be restarted.
*/
bool cleanup_offline_cgwb(struct bdi_writeback *wb)
{
struct cgroup_subsys_state *memcg_css;
struct inode_switch_wbs_context *isw;
struct inode *inode;
int nr;
bool restart = false;
isw = kzalloc(struct_size(isw, inodes, WB_MAX_INODES_PER_ISW),
GFP_KERNEL);
if (!isw)
return restart;
atomic_inc(&isw_nr_in_flight);
for (memcg_css = wb->memcg_css->parent; memcg_css;
memcg_css = memcg_css->parent) {
isw->new_wb = wb_get_create(wb->bdi, memcg_css, GFP_KERNEL);
if (isw->new_wb)
break;
}
if (unlikely(!isw->new_wb))
isw->new_wb = &wb->bdi->wb; /* wb_get() is noop for bdi's wb */
nr = 0;
spin_lock(&wb->list_lock);
list_for_each_entry(inode, &wb->b_attached, i_io_list) {
if (!inode_prepare_wbs_switch(inode, isw->new_wb))
continue;
isw->inodes[nr++] = inode;
if (nr >= WB_MAX_INODES_PER_ISW - 1) {
restart = true;
break;
}
}
spin_unlock(&wb->list_lock);
/* no attached inodes? bail out */
if (nr == 0) {
atomic_dec(&isw_nr_in_flight);
wb_put(isw->new_wb);
kfree(isw);
return restart;
}
/*
* In addition to synchronizing among switchers, I_WB_SWITCH tells
* the RCU protected stat update paths to grab the i_page
* lock so that stat transfer can synchronize against them.
* Let's continue after I_WB_SWITCH is guaranteed to be visible.
*/
INIT_RCU_WORK(&isw->work, inode_switch_wbs_work_fn);
queue_rcu_work(isw_wq, &isw->work);
return restart;
}
/**
* wbc_attach_and_unlock_inode - associate wbc with target inode and unlock it
* @wbc: writeback_control of interest
* @inode: target inode
*
* @inode is locked and about to be written back under the control of @wbc.
* Record @inode's writeback context into @wbc and unlock the i_lock. On
* writeback completion, wbc_detach_inode() should be called. This is used
* to track the cgroup writeback context.
*/
void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
struct inode *inode)
{
if (!inode_cgwb_enabled(inode)) {
spin_unlock(&inode->i_lock);
return;
}
wbc->wb = inode_to_wb(inode);
wbc->inode = inode;
wbc->wb_id = wbc->wb->memcg_css->id;
wbc->wb_lcand_id = inode->i_wb_frn_winner;
wbc->wb_tcand_id = 0;
wbc->wb_bytes = 0;
wbc->wb_lcand_bytes = 0;
wbc->wb_tcand_bytes = 0;
wb_get(wbc->wb);
spin_unlock(&inode->i_lock);
/*
* A dying wb indicates that either the blkcg associated with the
* memcg changed or the associated memcg is dying. In the first
* case, a replacement wb should already be available and we should
* refresh the wb immediately. In the second case, trying to
* refresh will keep failing.
*/
if (unlikely(wb_dying(wbc->wb) && !css_is_dying(wbc->wb->memcg_css)))
inode_switch_wbs(inode, wbc->wb_id);
}
EXPORT_SYMBOL_GPL(wbc_attach_and_unlock_inode);
/**
* wbc_detach_inode - disassociate wbc from inode and perform foreign detection
* @wbc: writeback_control of the just finished writeback
*
* To be called after a writeback attempt of an inode finishes and undoes
* wbc_attach_and_unlock_inode(). Can be called under any context.
*
* As concurrent write sharing of an inode is expected to be very rare and
* memcg only tracks page ownership on first-use basis severely confining
* the usefulness of such sharing, cgroup writeback tracks ownership
* per-inode. While the support for concurrent write sharing of an inode
* is deemed unnecessary, an inode being written to by different cgroups at
* different points in time is a lot more common, and, more importantly,
* charging only by first-use can too readily lead to grossly incorrect
* behaviors (single foreign page can lead to gigabytes of writeback to be
* incorrectly attributed).
*
* To resolve this issue, cgroup writeback detects the majority dirtier of
* an inode and transfers the ownership to it. To avoid unnecessary
* oscillation, the detection mechanism keeps track of history and gives
* out the switch verdict only if the foreign usage pattern is stable over
* a certain amount of time and/or writeback attempts.
*
* On each writeback attempt, @wbc tries to detect the majority writer
* using Boyer-Moore majority vote algorithm. In addition to the byte
* count from the majority voting, it also counts the bytes written for the
* current wb and the last round's winner wb (max of last round's current
* wb, the winner from two rounds ago, and the last round's majority
* candidate). Keeping track of the historical winner helps the algorithm
* to semi-reliably detect the most active writer even when it's not the
* absolute majority.
*
* Once the winner of the round is determined, whether the winner is
* foreign or not and how much IO time the round consumed is recorded in
* inode->i_wb_frn_history. If the amount of recorded foreign IO time is
* over a certain threshold, the switch verdict is given.
*/
void wbc_detach_inode(struct writeback_control *wbc)
{
struct bdi_writeback *wb = wbc->wb;
struct inode *inode = wbc->inode;
unsigned long avg_time, max_bytes, max_time;
u16 history;
int max_id;
if (!wb)
return;
history = inode->i_wb_frn_history;
avg_time = inode->i_wb_frn_avg_time;
/* pick the winner of this round */
if (wbc->wb_bytes >= wbc->wb_lcand_bytes &&
wbc->wb_bytes >= wbc->wb_tcand_bytes) {
max_id = wbc->wb_id;
max_bytes = wbc->wb_bytes;
} else if (wbc->wb_lcand_bytes >= wbc->wb_tcand_bytes) {
max_id = wbc->wb_lcand_id;
max_bytes = wbc->wb_lcand_bytes;
} else {
max_id = wbc->wb_tcand_id;
max_bytes = wbc->wb_tcand_bytes;
}
/*
* Calculate the amount of IO time the winner consumed and fold it
* into the running average kept per inode. If the consumed IO
* time is lower than avag / WB_FRN_TIME_CUT_DIV, ignore it for
* deciding whether to switch or not. This is to prevent one-off
* small dirtiers from skewing the verdict.
*/
max_time = DIV_ROUND_UP((max_bytes >> PAGE_SHIFT) << WB_FRN_TIME_SHIFT,
wb->avg_write_bandwidth);
if (avg_time)
avg_time += (max_time >> WB_FRN_TIME_AVG_SHIFT) -
(avg_time >> WB_FRN_TIME_AVG_SHIFT);
else
avg_time = max_time; /* immediate catch up on first run */
if (max_time >= avg_time / WB_FRN_TIME_CUT_DIV) {
int slots;
/*
* The switch verdict is reached if foreign wb's consume
* more than a certain proportion of IO time in a
* WB_FRN_TIME_PERIOD. This is loosely tracked by 16 slot
* history mask where each bit represents one sixteenth of
* the period. Determine the number of slots to shift into
* history from @max_time.
*/
slots = min(DIV_ROUND_UP(max_time, WB_FRN_HIST_UNIT),
(unsigned long)WB_FRN_HIST_MAX_SLOTS);
history <<= slots;
if (wbc->wb_id != max_id)
history |= (1U << slots) - 1;
if (history)
trace_inode_foreign_history(inode, wbc, history);
/*
* Switch if the current wb isn't the consistent winner.
* If there are multiple closely competing dirtiers, the
* inode may switch across them repeatedly over time, which
* is okay. The main goal is avoiding keeping an inode on
* the wrong wb for an extended period of time.
*/
if (hweight16(history) > WB_FRN_HIST_THR_SLOTS)
inode_switch_wbs(inode, max_id);
}
/*
* Multiple instances of this function may race to update the
* following fields but we don't mind occassional inaccuracies.
*/
inode->i_wb_frn_winner = max_id;
inode->i_wb_frn_avg_time = min(avg_time, (unsigned long)U16_MAX);
inode->i_wb_frn_history = history;
wb_put(wbc->wb);
wbc->wb = NULL;
}
EXPORT_SYMBOL_GPL(wbc_detach_inode);
/**
* wbc_account_cgroup_owner - account writeback to update inode cgroup ownership
* @wbc: writeback_control of the writeback in progress
* @page: page being written out
* @bytes: number of bytes being written out
*
* @bytes from @page are about to written out during the writeback
* controlled by @wbc. Keep the book for foreign inode detection. See
* wbc_detach_inode().
*/
void wbc_account_cgroup_owner(struct writeback_control *wbc, struct page *page,
size_t bytes)
{
struct folio *folio;
struct cgroup_subsys_state *css;
int id;
/*
* pageout() path doesn't attach @wbc to the inode being written
* out. This is intentional as we don't want the function to block
* behind a slow cgroup. Ultimately, we want pageout() to kick off
* regular writeback instead of writing things out itself.
*/
if (!wbc->wb || wbc->no_cgroup_owner)
return;
folio = page_folio(page);
css = mem_cgroup_css_from_folio(folio);
/* dead cgroups shouldn't contribute to inode ownership arbitration */
if (!(css->flags & CSS_ONLINE))
return;
id = css->id;
if (id == wbc->wb_id) {
wbc->wb_bytes += bytes;
return;
}
if (id == wbc->wb_lcand_id)
wbc->wb_lcand_bytes += bytes;
/* Boyer-Moore majority vote algorithm */
if (!wbc->wb_tcand_bytes)
wbc->wb_tcand_id = id;
if (id == wbc->wb_tcand_id)
wbc->wb_tcand_bytes += bytes;
else
wbc->wb_tcand_bytes -= min(bytes, wbc->wb_tcand_bytes);
}
EXPORT_SYMBOL_GPL(wbc_account_cgroup_owner);
/**
* wb_split_bdi_pages - split nr_pages to write according to bandwidth
* @wb: target bdi_writeback to split @nr_pages to
* @nr_pages: number of pages to write for the whole bdi
*
* Split @wb's portion of @nr_pages according to @wb's write bandwidth in
* relation to the total write bandwidth of all wb's w/ dirty inodes on
* @wb->bdi.
*/
static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages)
{
unsigned long this_bw = wb->avg_write_bandwidth;
unsigned long tot_bw = atomic_long_read(&wb->bdi->tot_write_bandwidth);
if (nr_pages == LONG_MAX)
return LONG_MAX;
/*
* This may be called on clean wb's and proportional distribution
* may not make sense, just use the original @nr_pages in those
* cases. In general, we wanna err on the side of writing more.
*/
if (!tot_bw || this_bw >= tot_bw)
return nr_pages;
else
return DIV_ROUND_UP_ULL((u64)nr_pages * this_bw, tot_bw);
}
/**
* bdi_split_work_to_wbs - split a wb_writeback_work to all wb's of a bdi
* @bdi: target backing_dev_info
* @base_work: wb_writeback_work to issue
* @skip_if_busy: skip wb's which already have writeback in progress
*
* Split and issue @base_work to all wb's (bdi_writeback's) of @bdi which
* have dirty inodes. If @base_work->nr_page isn't %LONG_MAX, it's
* distributed to the busy wbs according to each wb's proportion in the
* total active write bandwidth of @bdi.
*/
static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
struct wb_writeback_work *base_work,
bool skip_if_busy)
{
struct bdi_writeback *last_wb = NULL;
struct bdi_writeback *wb = list_entry(&bdi->wb_list,
struct bdi_writeback, bdi_node);
might_sleep();
restart:
rcu_read_lock();
list_for_each_entry_continue_rcu(wb, &bdi->wb_list, bdi_node) {
DEFINE_WB_COMPLETION(fallback_work_done, bdi);
struct wb_writeback_work fallback_work;
struct wb_writeback_work *work;
long nr_pages;
if (last_wb) {
wb_put(last_wb);
last_wb = NULL;
}
/* SYNC_ALL writes out I_DIRTY_TIME too */
if (!wb_has_dirty_io(wb) &&
(base_work->sync_mode == WB_SYNC_NONE ||
list_empty(&wb->b_dirty_time)))
continue;
if (skip_if_busy && writeback_in_progress(wb))
continue;
nr_pages = wb_split_bdi_pages(wb, base_work->nr_pages);
work = kmalloc(sizeof(*work), GFP_ATOMIC);
if (work) {
*work = *base_work;
work->nr_pages = nr_pages;
work->auto_free = 1;
wb_queue_work(wb, work);
continue;
}
/*
* If wb_tryget fails, the wb has been shutdown, skip it.
*
* Pin @wb so that it stays on @bdi->wb_list. This allows
* continuing iteration from @wb after dropping and
* regrabbing rcu read lock.
*/
if (!wb_tryget(wb))
continue;
/* alloc failed, execute synchronously using on-stack fallback */
work = &fallback_work;
*work = *base_work;
work->nr_pages = nr_pages;
work->auto_free = 0;
work->done = &fallback_work_done;
wb_queue_work(wb, work);
last_wb = wb;
rcu_read_unlock();
wb_wait_for_completion(&fallback_work_done);
goto restart;
}
rcu_read_unlock();
if (last_wb)
wb_put(last_wb);
}
/**
* cgroup_writeback_by_id - initiate cgroup writeback from bdi and memcg IDs
* @bdi_id: target bdi id
* @memcg_id: target memcg css id
* @reason: reason why some writeback work initiated
* @done: target wb_completion
*
* Initiate flush of the bdi_writeback identified by @bdi_id and @memcg_id
* with the specified parameters.
*/
int cgroup_writeback_by_id(u64 bdi_id, int memcg_id,
enum wb_reason reason, struct wb_completion *done)
{
struct backing_dev_info *bdi;
struct cgroup_subsys_state *memcg_css;
struct bdi_writeback *wb;
struct wb_writeback_work *work;
unsigned long dirty;
int ret;
/* lookup bdi and memcg */
bdi = bdi_get_by_id(bdi_id);
if (!bdi)
return -ENOENT;
rcu_read_lock();
memcg_css = css_from_id(memcg_id, &memory_cgrp_subsys);
if (memcg_css && !css_tryget(memcg_css))
memcg_css = NULL;
rcu_read_unlock();
if (!memcg_css) {
ret = -ENOENT;
goto out_bdi_put;
}
/*
* And find the associated wb. If the wb isn't there already
* there's nothing to flush, don't create one.
*/
wb = wb_get_lookup(bdi, memcg_css);
if (!wb) {
ret = -ENOENT;
goto out_css_put;
}
/*
* The caller is attempting to write out most of
* the currently dirty pages. Let's take the current dirty page
* count and inflate it by 25% which should be large enough to
* flush out most dirty pages while avoiding getting livelocked by
* concurrent dirtiers.
*
* BTW the memcg stats are flushed periodically and this is best-effort
* estimation, so some potential error is ok.
*/
dirty = memcg_page_state(mem_cgroup_from_css(memcg_css), NR_FILE_DIRTY);
dirty = dirty * 10 / 8;
/* issue the writeback work */
work = kzalloc(sizeof(*work), GFP_NOWAIT | __GFP_NOWARN);
if (work) {
work->nr_pages = dirty;
work->sync_mode = WB_SYNC_NONE;
work->range_cyclic = 1;
work->reason = reason;
work->done = done;
work->auto_free = 1;
wb_queue_work(wb, work);
ret = 0;
} else {
ret = -ENOMEM;
}
wb_put(wb);
out_css_put:
css_put(memcg_css);
out_bdi_put:
bdi_put(bdi);
return ret;
}
/**
* cgroup_writeback_umount - flush inode wb switches for umount
*
* This function is called when a super_block is about to be destroyed and
* flushes in-flight inode wb switches. An inode wb switch goes through
* RCU and then workqueue, so the two need to be flushed in order to ensure
* that all previously scheduled switches are finished. As wb switches are
* rare occurrences and synchronize_rcu() can take a while, perform
* flushing iff wb switches are in flight.
*/
void cgroup_writeback_umount(void)
{
/*
* SB_ACTIVE should be reliably cleared before checking
* isw_nr_in_flight, see generic_shutdown_super().
*/
smp_mb();
if (atomic_read(&isw_nr_in_flight)) {
/*
* Use rcu_barrier() to wait for all pending callbacks to
* ensure that all in-flight wb switches are in the workqueue.
*/
rcu_barrier();
flush_workqueue(isw_wq);
}
}
static int __init cgroup_writeback_init(void)
{
isw_wq = alloc_workqueue("inode_switch_wbs", 0, 0);
if (!isw_wq)
return -ENOMEM;
return 0;
}
fs_initcall(cgroup_writeback_init);
#else /* CONFIG_CGROUP_WRITEBACK */
static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi) { }
static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi) { }
static void inode_cgwb_move_to_attached(struct inode *inode,
struct bdi_writeback *wb)
{
assert_spin_locked(&wb->list_lock);
assert_spin_locked(&inode->i_lock);
WARN_ON_ONCE(inode->i_state & I_FREEING);
inode->i_state &= ~I_SYNC_QUEUED;
list_del_init(&inode->i_io_list);
wb_io_lists_depopulated(wb);
}
static struct bdi_writeback *
locked_inode_to_wb_and_lock_list(struct inode *inode)
__releases(&inode->i_lock)
__acquires(&wb->list_lock)
{
struct bdi_writeback *wb = inode_to_wb(inode);
spin_unlock(&inode->i_lock);
spin_lock(&wb->list_lock);
return wb;
}
static struct bdi_writeback *inode_to_wb_and_lock_list(struct inode *inode)
__acquires(&wb->list_lock)
{
struct bdi_writeback *wb = inode_to_wb(inode);
spin_lock(&wb->list_lock);
return wb;
}
static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages)
{
return nr_pages;
}
static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
struct wb_writeback_work *base_work,
bool skip_if_busy)
{
might_sleep();
if (!skip_if_busy || !writeback_in_progress(&bdi->wb)) {
base_work->auto_free = 0;
wb_queue_work(&bdi->wb, base_work);
}
}
#endif /* CONFIG_CGROUP_WRITEBACK */
/*
* Add in the number of potentially dirty inodes, because each inode
* write can dirty pagecache in the underlying blockdev.
*/
static unsigned long get_nr_dirty_pages(void)
{
return global_node_page_state(NR_FILE_DIRTY) +
get_nr_dirty_inodes();
}
static void wb_start_writeback(struct bdi_writeback *wb, enum wb_reason reason)
{
if (!wb_has_dirty_io(wb))
return;
/*
* All callers of this function want to start writeback of all
* dirty pages. Places like vmscan can call this at a very
* high frequency, causing pointless allocations of tons of
* work items and keeping the flusher threads busy retrieving
* that work. Ensure that we only allow one of them pending and
* inflight at the time.
*/
if (test_bit(WB_start_all, &wb->state) ||
test_and_set_bit(WB_start_all, &wb->state))
return;
wb->start_all_reason = reason;
wb_wakeup(wb);
}
/**
* wb_start_background_writeback - start background writeback
* @wb: bdi_writback to write from
*
* Description:
* This makes sure WB_SYNC_NONE background writeback happens. When
* this function returns, it is only guaranteed that for given wb
* some IO is happening if we are over background dirty threshold.
* Caller need not hold sb s_umount semaphore.
*/
void wb_start_background_writeback(struct bdi_writeback *wb)
{
/*
* We just wake up the flusher thread. It will perform background
* writeback as soon as there is no other work to do.
*/
trace_writeback_wake_background(wb);
wb_wakeup(wb);
}
/*
* Remove the inode from the writeback list it is on.
*/
void inode_io_list_del(struct inode *inode)
{
struct bdi_writeback *wb;
wb = inode_to_wb_and_lock_list(inode);
spin_lock(&inode->i_lock);
inode->i_state &= ~I_SYNC_QUEUED;
list_del_init(&inode->i_io_list);
wb_io_lists_depopulated(wb);
spin_unlock(&inode->i_lock);
spin_unlock(&wb->list_lock);
}
EXPORT_SYMBOL(inode_io_list_del);
/*
* mark an inode as under writeback on the sb
*/
void sb_mark_inode_writeback(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
unsigned long flags;
if (list_empty(&inode->i_wb_list)) {
spin_lock_irqsave(&sb->s_inode_wblist_lock, flags);
if (list_empty(&inode->i_wb_list)) {
list_add_tail(&inode->i_wb_list, &sb->s_inodes_wb);
trace_sb_mark_inode_writeback(inode);
}
spin_unlock_irqrestore(&sb->s_inode_wblist_lock, flags);
}
}
/*
* clear an inode as under writeback on the sb
*/
void sb_clear_inode_writeback(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
unsigned long flags;
if (!list_empty(&inode->i_wb_list)) {
spin_lock_irqsave(&sb->s_inode_wblist_lock, flags);
if (!list_empty(&inode->i_wb_list)) {
list_del_init(&inode->i_wb_list);
trace_sb_clear_inode_writeback(inode);
}
spin_unlock_irqrestore(&sb->s_inode_wblist_lock, flags);
}
}
/*
* Redirty an inode: set its when-it-was dirtied timestamp and move it to the
* furthest end of its superblock's dirty-inode list.
*
* Before stamping the inode's ->dirtied_when, we check to see whether it is
* already the most-recently-dirtied inode on the b_dirty list. If that is
* the case then the inode must have been redirtied while it was being written
* out and we don't reset its dirtied_when.
*/
static void redirty_tail_locked(struct inode *inode, struct bdi_writeback *wb)
{
assert_spin_locked(&inode->i_lock);
inode->i_state &= ~I_SYNC_QUEUED;
/*
* When the inode is being freed just don't bother with dirty list
* tracking. Flush worker will ignore this inode anyway and it will
* trigger assertions in inode_io_list_move_locked().
*/
if (inode->i_state & I_FREEING) {
list_del_init(&inode->i_io_list);
wb_io_lists_depopulated(wb);
return;
}
if (!list_empty(&wb->b_dirty)) {
struct inode *tail;
tail = wb_inode(wb->b_dirty.next);
if (time_before(inode->dirtied_when, tail->dirtied_when))
inode->dirtied_when = jiffies;
}
inode_io_list_move_locked(inode, wb, &wb->b_dirty);
}
static void redirty_tail(struct inode *inode, struct bdi_writeback *wb)
{
spin_lock(&inode->i_lock);
redirty_tail_locked(inode, wb);
spin_unlock(&inode->i_lock);
}
/*
* requeue inode for re-scanning after bdi->b_io list is exhausted.
*/
static void requeue_io(struct inode *inode, struct bdi_writeback *wb)
{
inode_io_list_move_locked(inode, wb, &wb->b_more_io);
}
static void inode_sync_complete(struct inode *inode)
{
inode->i_state &= ~I_SYNC;
/* If inode is clean an unused, put it into LRU now... */
inode_add_lru(inode);
/* Waiters must see I_SYNC cleared before being woken up */
smp_mb();
wake_up_bit(&inode->i_state, __I_SYNC);
}
static bool inode_dirtied_after(struct inode *inode, unsigned long t)
{
bool ret = time_after(inode->dirtied_when, t);
#ifndef CONFIG_64BIT
/*
* For inodes being constantly redirtied, dirtied_when can get stuck.
* It _appears_ to be in the future, but is actually in distant past.
* This test is necessary to prevent such wrapped-around relative times
* from permanently stopping the whole bdi writeback.
*/
ret = ret && time_before_eq(inode->dirtied_when, jiffies);
#endif
return ret;
}
/*
* Move expired (dirtied before dirtied_before) dirty inodes from
* @delaying_queue to @dispatch_queue.
*/
static int move_expired_inodes(struct list_head *delaying_queue,
struct list_head *dispatch_queue,
unsigned long dirtied_before)
{
LIST_HEAD(tmp);
struct list_head *pos, *node;
struct super_block *sb = NULL;
struct inode *inode;
int do_sb_sort = 0;
int moved = 0;
while (!list_empty(delaying_queue)) {
inode = wb_inode(delaying_queue->prev);
if (inode_dirtied_after(inode, dirtied_before))
break;
spin_lock(&inode->i_lock);
list_move(&inode->i_io_list, &tmp);
moved++;
inode->i_state |= I_SYNC_QUEUED;
spin_unlock(&inode->i_lock);
if (sb_is_blkdev_sb(inode->i_sb))
continue;
if (sb && sb != inode->i_sb)
do_sb_sort = 1;
sb = inode->i_sb;
}
/* just one sb in list, splice to dispatch_queue and we're done */
if (!do_sb_sort) {
list_splice(&tmp, dispatch_queue);
goto out;
}
/*
* Although inode's i_io_list is moved from 'tmp' to 'dispatch_queue',
* we don't take inode->i_lock here because it is just a pointless overhead.
* Inode is already marked as I_SYNC_QUEUED so writeback list handling is
* fully under our control.
*/
while (!list_empty(&tmp)) {
sb = wb_inode(tmp.prev)->i_sb;
list_for_each_prev_safe(pos, node, &tmp) {
inode = wb_inode(pos);
if (inode->i_sb == sb)
list_move(&inode->i_io_list, dispatch_queue);
}
}
out:
return moved;
}
/*
* Queue all expired dirty inodes for io, eldest first.
* Before
* newly dirtied b_dirty b_io b_more_io
* =============> gf edc BA
* After
* newly dirtied b_dirty b_io b_more_io
* =============> g fBAedc
* |
* +--> dequeue for IO
*/
static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work,
unsigned long dirtied_before)
{
int moved;
unsigned long time_expire_jif = dirtied_before;
assert_spin_locked(&wb->list_lock);
list_splice_init(&wb->b_more_io, &wb->b_io);
moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, dirtied_before);
if (!work->for_sync)
time_expire_jif = jiffies - dirtytime_expire_interval * HZ;
moved += move_expired_inodes(&wb->b_dirty_time, &wb->b_io,
time_expire_jif);
if (moved)
wb_io_lists_populated(wb);
trace_writeback_queue_io(wb, work, dirtied_before, moved);
}
static int write_inode(struct inode *inode, struct writeback_control *wbc)
{
int ret;
if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) {
trace_writeback_write_inode_start(inode, wbc);
ret = inode->i_sb->s_op->write_inode(inode, wbc);
trace_writeback_write_inode(inode, wbc);
return ret;
}
return 0;
}
/*
* Wait for writeback on an inode to complete. Called with i_lock held.
* Caller must make sure inode cannot go away when we drop i_lock.
*/
static void __inode_wait_for_writeback(struct inode *inode)
__releases(inode->i_lock)
__acquires(inode->i_lock)
{
DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC);
wait_queue_head_t *wqh;
wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
while (inode->i_state & I_SYNC) {
spin_unlock(&inode->i_lock);
__wait_on_bit(wqh, &wq, bit_wait,
TASK_UNINTERRUPTIBLE);
spin_lock(&inode->i_lock);
}
}
/*
* Wait for writeback on an inode to complete. Caller must have inode pinned.
*/
void inode_wait_for_writeback(struct inode *inode)
{
spin_lock(&inode->i_lock);
__inode_wait_for_writeback(inode);
spin_unlock(&inode->i_lock);
}
/*
* Sleep until I_SYNC is cleared. This function must be called with i_lock
* held and drops it. It is aimed for callers not holding any inode reference
* so once i_lock is dropped, inode can go away.
*/
static void inode_sleep_on_writeback(struct inode *inode)
__releases(inode->i_lock)
{
DEFINE_WAIT(wait);
wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
int sleep;
prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
sleep = inode->i_state & I_SYNC;
spin_unlock(&inode->i_lock);
if (sleep)
schedule();
finish_wait(wqh, &wait);
}
/*
* Find proper writeback list for the inode depending on its current state and
* possibly also change of its state while we were doing writeback. Here we
* handle things such as livelock prevention or fairness of writeback among
* inodes. This function can be called only by flusher thread - noone else
* processes all inodes in writeback lists and requeueing inodes behind flusher
* thread's back can have unexpected consequences.
*/
static void requeue_inode(struct inode *inode, struct bdi_writeback *wb,
struct writeback_control *wbc)
{
if (inode->i_state & I_FREEING)
return;
/*
* Sync livelock prevention. Each inode is tagged and synced in one
* shot. If still dirty, it will be redirty_tail()'ed below. Update
* the dirty time to prevent enqueue and sync it again.
*/
if ((inode->i_state & I_DIRTY) &&
(wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages))
inode->dirtied_when = jiffies;
if (wbc->pages_skipped) {
/*
* writeback is not making progress due to locked
* buffers. Skip this inode for now.
*/
redirty_tail_locked(inode, wb);
return;
}
if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
/*
* We didn't write back all the pages. nfs_writepages()
* sometimes bales out without doing anything.
*/
if (wbc->nr_to_write <= 0) {
/* Slice used up. Queue for next turn. */
requeue_io(inode, wb);
} else {
/*
* Writeback blocked by something other than
* congestion. Delay the inode for some time to
* avoid spinning on the CPU (100% iowait)
* retrying writeback of the dirty page/inode
* that cannot be performed immediately.
*/
redirty_tail_locked(inode, wb);
}
} else if (inode->i_state & I_DIRTY) {
/*
* Filesystems can dirty the inode during writeback operations,
* such as delayed allocation during submission or metadata
* updates after data IO completion.
*/
redirty_tail_locked(inode, wb);
} else if (inode->i_state & I_DIRTY_TIME) {
inode->dirtied_when = jiffies;
inode_io_list_move_locked(inode, wb, &wb->b_dirty_time);
inode->i_state &= ~I_SYNC_QUEUED;
} else {
/* The inode is clean. Remove from writeback lists. */
inode_cgwb_move_to_attached(inode, wb);
}
}
/*
* Write out an inode and its dirty pages (or some of its dirty pages, depending
* on @wbc->nr_to_write), and clear the relevant dirty flags from i_state.
*
* This doesn't remove the inode from the writeback list it is on, except
* potentially to move it from b_dirty_time to b_dirty due to timestamp
* expiration. The caller is otherwise responsible for writeback list handling.
*
* The caller is also responsible for setting the I_SYNC flag beforehand and
* calling inode_sync_complete() to clear it afterwards.
*/
static int
__writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
{
struct address_space *mapping = inode->i_mapping;
long nr_to_write = wbc->nr_to_write;
unsigned dirty;
int ret;
WARN_ON(!(inode->i_state & I_SYNC));
trace_writeback_single_inode_start(inode, wbc, nr_to_write);
ret = do_writepages(mapping, wbc);
/*
* Make sure to wait on the data before writing out the metadata.
* This is important for filesystems that modify metadata on data
* I/O completion. We don't do it for sync(2) writeback because it has a
* separate, external IO completion path and ->sync_fs for guaranteeing
* inode metadata is written back correctly.
*/
if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync) {
int err = filemap_fdatawait(mapping);
if (ret == 0)
ret = err;
}
/*
* If the inode has dirty timestamps and we need to write them, call
* mark_inode_dirty_sync() to notify the filesystem about it and to
* change I_DIRTY_TIME into I_DIRTY_SYNC.
*/
if ((inode->i_state & I_DIRTY_TIME) &&
(wbc->sync_mode == WB_SYNC_ALL ||
time_after(jiffies, inode->dirtied_time_when +
dirtytime_expire_interval * HZ))) {
trace_writeback_lazytime(inode);
mark_inode_dirty_sync(inode);
}
/*
* Get and clear the dirty flags from i_state. This needs to be done
* after calling writepages because some filesystems may redirty the
* inode during writepages due to delalloc. It also needs to be done
* after handling timestamp expiration, as that may dirty the inode too.
*/
spin_lock(&inode->i_lock);
dirty = inode->i_state & I_DIRTY;
inode->i_state &= ~dirty;
/*
* Paired with smp_mb() in __mark_inode_dirty(). This allows
* __mark_inode_dirty() to test i_state without grabbing i_lock -
* either they see the I_DIRTY bits cleared or we see the dirtied
* inode.
*
* I_DIRTY_PAGES is always cleared together above even if @mapping
* still has dirty pages. The flag is reinstated after smp_mb() if
* necessary. This guarantees that either __mark_inode_dirty()
* sees clear I_DIRTY_PAGES or we see PAGECACHE_TAG_DIRTY.
*/
smp_mb();
if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
inode->i_state |= I_DIRTY_PAGES;
else if (unlikely(inode->i_state & I_PINNING_FSCACHE_WB)) {
if (!(inode->i_state & I_DIRTY_PAGES)) {
inode->i_state &= ~I_PINNING_FSCACHE_WB;
wbc->unpinned_fscache_wb = true;
dirty |= I_PINNING_FSCACHE_WB; /* Cause write_inode */
}
}
spin_unlock(&inode->i_lock);
/* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & ~I_DIRTY_PAGES) {
int err = write_inode(inode, wbc);
if (ret == 0)
ret = err;
}
wbc->unpinned_fscache_wb = false;
trace_writeback_single_inode(inode, wbc, nr_to_write);
return ret;
}
/*
* Write out an inode's dirty data and metadata on-demand, i.e. separately from
* the regular batched writeback done by the flusher threads in
* writeback_sb_inodes(). @wbc controls various aspects of the write, such as
* whether it is a data-integrity sync (%WB_SYNC_ALL) or not (%WB_SYNC_NONE).
*
* To prevent the inode from going away, either the caller must have a reference
* to the inode, or the inode must have I_WILL_FREE or I_FREEING set.
*/
static int writeback_single_inode(struct inode *inode,
struct writeback_control *wbc)
{
struct bdi_writeback *wb;
int ret = 0;
spin_lock(&inode->i_lock);
if (!atomic_read(&inode->i_count))
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else
WARN_ON(inode->i_state & I_WILL_FREE);
if (inode->i_state & I_SYNC) {
/*
* Writeback is already running on the inode. For WB_SYNC_NONE,
* that's enough and we can just return. For WB_SYNC_ALL, we
* must wait for the existing writeback to complete, then do
* writeback again if there's anything left.
*/
if (wbc->sync_mode != WB_SYNC_ALL)
goto out;
__inode_wait_for_writeback(inode);
}
WARN_ON(inode->i_state & I_SYNC);
/*
* If the inode is already fully clean, then there's nothing to do.
*
* For data-integrity syncs we also need to check whether any pages are
* still under writeback, e.g. due to prior WB_SYNC_NONE writeback. If
* there are any such pages, we'll need to wait for them.
*/
if (!(inode->i_state & I_DIRTY_ALL) &&
(wbc->sync_mode != WB_SYNC_ALL ||
!mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK)))
goto out;
inode->i_state |= I_SYNC;
wbc_attach_and_unlock_inode(wbc, inode);
ret = __writeback_single_inode(inode, wbc);
wbc_detach_inode(wbc);
wb = inode_to_wb_and_lock_list(inode);
spin_lock(&inode->i_lock);
/*
* If the inode is freeing, its i_io_list shoudn't be updated
* as it can be finally deleted at this moment.
*/
if (!(inode->i_state & I_FREEING)) {
/*
* If the inode is now fully clean, then it can be safely
* removed from its writeback list (if any). Otherwise the
* flusher threads are responsible for the writeback lists.
*/
if (!(inode->i_state & I_DIRTY_ALL))
inode_cgwb_move_to_attached(inode, wb);
else if (!(inode->i_state & I_SYNC_QUEUED)) {
if ((inode->i_state & I_DIRTY))
redirty_tail_locked(inode, wb);
else if (inode->i_state & I_DIRTY_TIME) {
inode->dirtied_when = jiffies;
inode_io_list_move_locked(inode,
wb,
&wb->b_dirty_time);
}
}
}
spin_unlock(&wb->list_lock);
inode_sync_complete(inode);
out:
spin_unlock(&inode->i_lock);
return ret;
}
static long writeback_chunk_size(struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
long pages;
/*
* WB_SYNC_ALL mode does livelock avoidance by syncing dirty
* inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX
* here avoids calling into writeback_inodes_wb() more than once.
*
* The intended call sequence for WB_SYNC_ALL writeback is:
*
* wb_writeback()
* writeback_sb_inodes() <== called only once
* write_cache_pages() <== called once for each inode
* (quickly) tag currently dirty pages
* (maybe slowly) sync all tagged pages
*/
if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages)
pages = LONG_MAX;
else {
pages = min(wb->avg_write_bandwidth / 2,
global_wb_domain.dirty_limit / DIRTY_SCOPE);
pages = min(pages, work->nr_pages);
pages = round_down(pages + MIN_WRITEBACK_PAGES,
MIN_WRITEBACK_PAGES);
}
return pages;
}
/*
* Write a portion of b_io inodes which belong to @sb.
*
* Return the number of pages and/or inodes written.
*
* NOTE! This is called with wb->list_lock held, and will
* unlock and relock that for each inode it ends up doing
* IO for.
*/
static long writeback_sb_inodes(struct super_block *sb,
struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
struct writeback_control wbc = {
.sync_mode = work->sync_mode,
.tagged_writepages = work->tagged_writepages,
.for_kupdate = work->for_kupdate,
.for_background = work->for_background,
.for_sync = work->for_sync,
.range_cyclic = work->range_cyclic,
.range_start = 0,
.range_end = LLONG_MAX,
};
unsigned long start_time = jiffies;
long write_chunk;
long total_wrote = 0; /* count both pages and inodes */
while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
struct bdi_writeback *tmp_wb;
long wrote;
if (inode->i_sb != sb) {
if (work->sb) {
/*
* We only want to write back data for this
* superblock, move all inodes not belonging
* to it back onto the dirty list.
*/
redirty_tail(inode, wb);
continue;
}
/*
* The inode belongs to a different superblock.
* Bounce back to the caller to unpin this and
* pin the next superblock.
*/
break;
}
/*
* Don't bother with new inodes or inodes being freed, first
* kind does not need periodic writeout yet, and for the latter
* kind writeout is handled by the freer.
*/
spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
redirty_tail_locked(inode, wb);
spin_unlock(&inode->i_lock);
continue;
}
if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) {
/*
* If this inode is locked for writeback and we are not
* doing writeback-for-data-integrity, move it to
* b_more_io so that writeback can proceed with the
* other inodes on s_io.
*
* We'll have another go at writing back this inode
* when we completed a full scan of b_io.
*/
requeue_io(inode, wb);
spin_unlock(&inode->i_lock);
trace_writeback_sb_inodes_requeue(inode);
continue;
}
spin_unlock(&wb->list_lock);
/*
* We already requeued the inode if it had I_SYNC set and we
* are doing WB_SYNC_NONE writeback. So this catches only the
* WB_SYNC_ALL case.
*/
if (inode->i_state & I_SYNC) {
/* Wait for I_SYNC. This function drops i_lock... */
inode_sleep_on_writeback(inode);
/* Inode may be gone, start again */
spin_lock(&wb->list_lock);
continue;
}
inode->i_state |= I_SYNC;
wbc_attach_and_unlock_inode(&wbc, inode);
write_chunk = writeback_chunk_size(wb, work);
wbc.nr_to_write = write_chunk;
wbc.pages_skipped = 0;
/*
* We use I_SYNC to pin the inode in memory. While it is set
* evict_inode() will wait so the inode cannot be freed.
*/
__writeback_single_inode(inode, &wbc);
wbc_detach_inode(&wbc);
work->nr_pages -= write_chunk - wbc.nr_to_write;
wrote = write_chunk - wbc.nr_to_write - wbc.pages_skipped;
wrote = wrote < 0 ? 0 : wrote;
total_wrote += wrote;
if (need_resched()) {
/*
* We're trying to balance between building up a nice
* long list of IOs to improve our merge rate, and
* getting those IOs out quickly for anyone throttling
* in balance_dirty_pages(). cond_resched() doesn't
* unplug, so get our IOs out the door before we
* give up the CPU.
*/
blk_flush_plug(current->plug, false);
cond_resched();
}
/*
* Requeue @inode if still dirty. Be careful as @inode may
* have been switched to another wb in the meantime.
*/
tmp_wb = inode_to_wb_and_lock_list(inode);
spin_lock(&inode->i_lock);
if (!(inode->i_state & I_DIRTY_ALL))
total_wrote++;
requeue_inode(inode, tmp_wb, &wbc);
inode_sync_complete(inode);
spin_unlock(&inode->i_lock);
if (unlikely(tmp_wb != wb)) {
spin_unlock(&tmp_wb->list_lock);
spin_lock(&wb->list_lock);
}
/*
* bail out to wb_writeback() often enough to check
* background threshold and other termination conditions.
*/
if (total_wrote) {
if (time_is_before_jiffies(start_time + HZ / 10UL))
break;
if (work->nr_pages <= 0)
break;
}
}
return total_wrote;
}
static long __writeback_inodes_wb(struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
unsigned long start_time = jiffies;
long wrote = 0;
while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
struct super_block *sb = inode->i_sb;
if (!super_trylock_shared(sb)) {
/*
* super_trylock_shared() may fail consistently due to
* s_umount being grabbed by someone else. Don't use
* requeue_io() to avoid busy retrying the inode/sb.
*/
redirty_tail(inode, wb);
continue;
}
wrote += writeback_sb_inodes(sb, wb, work);
up_read(&sb->s_umount);
/* refer to the same tests at the end of writeback_sb_inodes */
if (wrote) {
if (time_is_before_jiffies(start_time + HZ / 10UL))
break;
if (work->nr_pages <= 0)
break;
}
}
/* Leave any unwritten inodes on b_io */
return wrote;
}
static long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
enum wb_reason reason)
{
struct wb_writeback_work work = {
.nr_pages = nr_pages,
.sync_mode = WB_SYNC_NONE,
.range_cyclic = 1,
.reason = reason,
};
struct blk_plug plug;
blk_start_plug(&plug);
spin_lock(&wb->list_lock);
if (list_empty(&wb->b_io))
queue_io(wb, &work, jiffies);
__writeback_inodes_wb(wb, &work);
spin_unlock(&wb->list_lock);
blk_finish_plug(&plug);
return nr_pages - work.nr_pages;
}
/*
* Explicit flushing or periodic writeback of "old" data.
*
* Define "old": the first time one of an inode's pages is dirtied, we mark the
* dirtying-time in the inode's address_space. So this periodic writeback code
* just walks the superblock inode list, writing back any inodes which are
* older than a specific point in time.
*
* Try to run once per dirty_writeback_interval. But if a writeback event
* takes longer than a dirty_writeback_interval interval, then leave a
* one-second gap.
*
* dirtied_before takes precedence over nr_to_write. So we'll only write back
* all dirty pages if they are all attached to "old" mappings.
*/
static long wb_writeback(struct bdi_writeback *wb,
struct wb_writeback_work *work)
{
long nr_pages = work->nr_pages;
unsigned long dirtied_before = jiffies;
struct inode *inode;
long progress;
struct blk_plug plug;
blk_start_plug(&plug);
for (;;) {
/*
* Stop writeback when nr_pages has been consumed
*/
if (work->nr_pages <= 0)
break;
/*
* Background writeout and kupdate-style writeback may
* run forever. Stop them if there is other work to do
* so that e.g. sync can proceed. They'll be restarted
* after the other works are all done.
*/
if ((work->for_background || work->for_kupdate) &&
!list_empty(&wb->work_list))
break;
/*
* For background writeout, stop when we are below the
* background dirty threshold
*/
if (work->for_background && !wb_over_bg_thresh(wb))
break;
spin_lock(&wb->list_lock);
/*
* Kupdate and background works are special and we want to
* include all inodes that need writing. Livelock avoidance is
* handled by these works yielding to any other work so we are
* safe.
*/
if (work->for_kupdate) {
dirtied_before = jiffies -
msecs_to_jiffies(dirty_expire_interval * 10);
} else if (work->for_background)
dirtied_before = jiffies;
trace_writeback_start(wb, work);
if (list_empty(&wb->b_io))
queue_io(wb, work, dirtied_before);
if (work->sb)
progress = writeback_sb_inodes(work->sb, wb, work);
else
progress = __writeback_inodes_wb(wb, work);
trace_writeback_written(wb, work);
/*
* Did we write something? Try for more
*
* Dirty inodes are moved to b_io for writeback in batches.
* The completion of the current batch does not necessarily
* mean the overall work is done. So we keep looping as long
* as made some progress on cleaning pages or inodes.
*/
if (progress) {
spin_unlock(&wb->list_lock);
continue;
}
/*
* No more inodes for IO, bail
*/
if (list_empty(&wb->b_more_io)) {
spin_unlock(&wb->list_lock);
break;
}
/*
* Nothing written. Wait for some inode to
* become available for writeback. Otherwise
* we'll just busyloop.
*/
trace_writeback_wait(wb, work);
inode = wb_inode(wb->b_more_io.prev);
spin_lock(&inode->i_lock);
spin_unlock(&wb->list_lock);
/* This function drops i_lock... */
inode_sleep_on_writeback(inode);
}
blk_finish_plug(&plug);
return nr_pages - work->nr_pages;
}
/*
* Return the next wb_writeback_work struct that hasn't been processed yet.
*/
static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb)
{
struct wb_writeback_work *work = NULL;
spin_lock_irq(&wb->work_lock);
if (!list_empty(&wb->work_list)) {
work = list_entry(wb->work_list.next,
struct wb_writeback_work, list);
list_del_init(&work->list);
}
spin_unlock_irq(&wb->work_lock);
return work;
}
static long wb_check_background_flush(struct bdi_writeback *wb)
{
if (wb_over_bg_thresh(wb)) {
struct wb_writeback_work work = {
.nr_pages = LONG_MAX,
.sync_mode = WB_SYNC_NONE,
.for_background = 1,
.range_cyclic = 1,
.reason = WB_REASON_BACKGROUND,
};
return wb_writeback(wb, &work);
}
return 0;
}
static long wb_check_old_data_flush(struct bdi_writeback *wb)
{
unsigned long expired;
long nr_pages;
/*
* When set to zero, disable periodic writeback
*/
if (!dirty_writeback_interval)
return 0;
expired = wb->last_old_flush +
msecs_to_jiffies(dirty_writeback_interval * 10);
if (time_before(jiffies, expired))
return 0;
wb->last_old_flush = jiffies;
nr_pages = get_nr_dirty_pages();
if (nr_pages) {
struct wb_writeback_work work = {
.nr_pages = nr_pages,
.sync_mode = WB_SYNC_NONE,
.for_kupdate = 1,
.range_cyclic = 1,
.reason = WB_REASON_PERIODIC,
};
return wb_writeback(wb, &work);
}
return 0;
}
static long wb_check_start_all(struct bdi_writeback *wb)
{
long nr_pages;
if (!test_bit(WB_start_all, &wb->state))
return 0;
nr_pages = get_nr_dirty_pages();
if (nr_pages) {
struct wb_writeback_work work = {
.nr_pages = wb_split_bdi_pages(wb, nr_pages),
.sync_mode = WB_SYNC_NONE,
.range_cyclic = 1,
.reason = wb->start_all_reason,
};
nr_pages = wb_writeback(wb, &work);
}
clear_bit(WB_start_all, &wb->state);
return nr_pages;
}
/*
* Retrieve work items and do the writeback they describe
*/
static long wb_do_writeback(struct bdi_writeback *wb)
{
struct wb_writeback_work *work;
long wrote = 0;
set_bit(WB_writeback_running, &wb->state);
while ((work = get_next_work_item(wb)) != NULL) {
trace_writeback_exec(wb, work);
wrote += wb_writeback(wb, work);
finish_writeback_work(wb, work);
}
/*
* Check for a flush-everything request
*/
wrote += wb_check_start_all(wb);
/*
* Check for periodic writeback, kupdated() style
*/
wrote += wb_check_old_data_flush(wb);
wrote += wb_check_background_flush(wb);
clear_bit(WB_writeback_running, &wb->state);
return wrote;
}
/*
* Handle writeback of dirty data for the device backed by this bdi. Also
* reschedules periodically and does kupdated style flushing.
*/
void wb_workfn(struct work_struct *work)
{
struct bdi_writeback *wb = container_of(to_delayed_work(work),
struct bdi_writeback, dwork);
long pages_written;
set_worker_desc("flush-%s", bdi_dev_name(wb->bdi));
if (likely(!current_is_workqueue_rescuer() ||
!test_bit(WB_registered, &wb->state))) {
/*
* The normal path. Keep writing back @wb until its
* work_list is empty. Note that this path is also taken
* if @wb is shutting down even when we're running off the
* rescuer as work_list needs to be drained.
*/
do {
pages_written = wb_do_writeback(wb);
trace_writeback_pages_written(pages_written);
} while (!list_empty(&wb->work_list));
} else {
/*
* bdi_wq can't get enough workers and we're running off
* the emergency worker. Don't hog it. Hopefully, 1024 is
* enough for efficient IO.
*/
pages_written = writeback_inodes_wb(wb, 1024,
WB_REASON_FORKER_THREAD);
trace_writeback_pages_written(pages_written);
}
if (!list_empty(&wb->work_list))
wb_wakeup(wb);
else if (wb_has_dirty_io(wb) && dirty_writeback_interval)
wb_wakeup_delayed(wb);
}
/*
* Start writeback of `nr_pages' pages on this bdi. If `nr_pages' is zero,
* write back the whole world.
*/
static void __wakeup_flusher_threads_bdi(struct backing_dev_info *bdi,
enum wb_reason reason)
{
struct bdi_writeback *wb;
if (!bdi_has_dirty_io(bdi))
return;
list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node)
wb_start_writeback(wb, reason);
}
void wakeup_flusher_threads_bdi(struct backing_dev_info *bdi,
enum wb_reason reason)
{
rcu_read_lock();
__wakeup_flusher_threads_bdi(bdi, reason);
rcu_read_unlock();
}
/*
* Wakeup the flusher threads to start writeback of all currently dirty pages
*/
void wakeup_flusher_threads(enum wb_reason reason)
{
struct backing_dev_info *bdi;
/*
* If we are expecting writeback progress we must submit plugged IO.
*/
blk_flush_plug(current->plug, true);
rcu_read_lock();
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list)
__wakeup_flusher_threads_bdi(bdi, reason);
rcu_read_unlock();
}
/*
* Wake up bdi's periodically to make sure dirtytime inodes gets
* written back periodically. We deliberately do *not* check the
* b_dirtytime list in wb_has_dirty_io(), since this would cause the
* kernel to be constantly waking up once there are any dirtytime
* inodes on the system. So instead we define a separate delayed work
* function which gets called much more rarely. (By default, only
* once every 12 hours.)
*
* If there is any other write activity going on in the file system,
* this function won't be necessary. But if the only thing that has
* happened on the file system is a dirtytime inode caused by an atime
* update, we need this infrastructure below to make sure that inode
* eventually gets pushed out to disk.
*/
static void wakeup_dirtytime_writeback(struct work_struct *w);
static DECLARE_DELAYED_WORK(dirtytime_work, wakeup_dirtytime_writeback);
static void wakeup_dirtytime_writeback(struct work_struct *w)
{
struct backing_dev_info *bdi;
rcu_read_lock();
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
struct bdi_writeback *wb;
list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node)
if (!list_empty(&wb->b_dirty_time))
wb_wakeup(wb);
}
rcu_read_unlock();
schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ);
}
static int __init start_dirtytime_writeback(void)
{
schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ);
return 0;
}
__initcall(start_dirtytime_writeback);
int dirtytime_interval_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (ret == 0 && write)
mod_delayed_work(system_wq, &dirtytime_work, 0);
return ret;
}
/**
* __mark_inode_dirty - internal function to mark an inode dirty
*
* @inode: inode to mark
* @flags: what kind of dirty, e.g. I_DIRTY_SYNC. This can be a combination of
* multiple I_DIRTY_* flags, except that I_DIRTY_TIME can't be combined
* with I_DIRTY_PAGES.
*
* Mark an inode as dirty. We notify the filesystem, then update the inode's
* dirty flags. Then, if needed we add the inode to the appropriate dirty list.
*
* Most callers should use mark_inode_dirty() or mark_inode_dirty_sync()
* instead of calling this directly.
*
* CAREFUL! We only add the inode to the dirty list if it is hashed or if it
* refers to a blockdev. Unhashed inodes will never be added to the dirty list
* even if they are later hashed, as they will have been marked dirty already.
*
* In short, ensure you hash any inodes _before_ you start marking them dirty.
*
* Note that for blockdevs, inode->dirtied_when represents the dirtying time of
* the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of
* the kernel-internal blockdev inode represents the dirtying time of the
* blockdev's pages. This is why for I_DIRTY_PAGES we always use
* page->mapping->host, so the page-dirtying time is recorded in the internal
* blockdev inode.
*/
void __mark_inode_dirty(struct inode *inode, int flags)
{
struct super_block *sb = inode->i_sb;
int dirtytime = 0;
struct bdi_writeback *wb = NULL;
trace_writeback_mark_inode_dirty(inode, flags);
if (flags & I_DIRTY_INODE) {
/*
* Inode timestamp update will piggback on this dirtying.
* We tell ->dirty_inode callback that timestamps need to
* be updated by setting I_DIRTY_TIME in flags.
*/
if (inode->i_state & I_DIRTY_TIME) {
spin_lock(&inode->i_lock);
if (inode->i_state & I_DIRTY_TIME) {
inode->i_state &= ~I_DIRTY_TIME;
flags |= I_DIRTY_TIME;
}
spin_unlock(&inode->i_lock);
}
/*
* Notify the filesystem about the inode being dirtied, so that
* (if needed) it can update on-disk fields and journal the
* inode. This is only needed when the inode itself is being
* dirtied now. I.e. it's only needed for I_DIRTY_INODE, not
* for just I_DIRTY_PAGES or I_DIRTY_TIME.
*/
trace_writeback_dirty_inode_start(inode, flags);
if (sb->s_op->dirty_inode)
sb->s_op->dirty_inode(inode,
flags & (I_DIRTY_INODE | I_DIRTY_TIME));
trace_writeback_dirty_inode(inode, flags);
/* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
flags &= ~I_DIRTY_TIME;
} else {
/*
* Else it's either I_DIRTY_PAGES, I_DIRTY_TIME, or nothing.
* (We don't support setting both I_DIRTY_PAGES and I_DIRTY_TIME
* in one call to __mark_inode_dirty().)
*/
dirtytime = flags & I_DIRTY_TIME;
WARN_ON_ONCE(dirtytime && flags != I_DIRTY_TIME);
}
/*
* Paired with smp_mb() in __writeback_single_inode() for the
* following lockless i_state test. See there for details.
*/
smp_mb();
if ((inode->i_state & flags) == flags)
return;
spin_lock(&inode->i_lock);
if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY;
inode_attach_wb(inode, NULL);
inode->i_state |= flags;
/*
* Grab inode's wb early because it requires dropping i_lock and we
* need to make sure following checks happen atomically with dirty
* list handling so that we don't move inodes under flush worker's
* hands.
*/
if (!was_dirty) {
wb = locked_inode_to_wb_and_lock_list(inode);
spin_lock(&inode->i_lock);
}
/*
* If the inode is queued for writeback by flush worker, just
* update its dirty state. Once the flush worker is done with
* the inode it will place it on the appropriate superblock
* list, based upon its state.
*/
if (inode->i_state & I_SYNC_QUEUED)
goto out_unlock;
/*
* Only add valid (hashed) inodes to the superblock's
* dirty list. Add blockdev inodes as well.
*/
if (!S_ISBLK(inode->i_mode)) {
if (inode_unhashed(inode))
goto out_unlock;
}
if (inode->i_state & I_FREEING)
goto out_unlock;
/*
* If the inode was already on b_dirty/b_io/b_more_io, don't
* reposition it (that would break b_dirty time-ordering).
*/
if (!was_dirty) {
struct list_head *dirty_list;
bool wakeup_bdi = false;
inode->dirtied_when = jiffies;
if (dirtytime)
inode->dirtied_time_when = jiffies;
if (inode->i_state & I_DIRTY)
dirty_list = &wb->b_dirty;
else
dirty_list = &wb->b_dirty_time;
wakeup_bdi = inode_io_list_move_locked(inode, wb,
dirty_list);
spin_unlock(&wb->list_lock);
spin_unlock(&inode->i_lock);
trace_writeback_dirty_inode_enqueue(inode);
/*
* If this is the first dirty inode for this bdi,
* we have to wake-up the corresponding bdi thread
* to make sure background write-back happens
* later.
*/
if (wakeup_bdi &&
(wb->bdi->capabilities & BDI_CAP_WRITEBACK))
wb_wakeup_delayed(wb);
return;
}
}
out_unlock:
if (wb)
spin_unlock(&wb->list_lock);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(__mark_inode_dirty);
/*
* The @s_sync_lock is used to serialise concurrent sync operations
* to avoid lock contention problems with concurrent wait_sb_inodes() calls.
* Concurrent callers will block on the s_sync_lock rather than doing contending
* walks. The queueing maintains sync(2) required behaviour as all the IO that
* has been issued up to the time this function is enter is guaranteed to be
* completed by the time we have gained the lock and waited for all IO that is
* in progress regardless of the order callers are granted the lock.
*/
static void wait_sb_inodes(struct super_block *sb)
{
LIST_HEAD(sync_list);
/*
* We need to be protected against the filesystem going from
* r/o to r/w or vice versa.
*/
WARN_ON(!rwsem_is_locked(&sb->s_umount));
mutex_lock(&sb->s_sync_lock);
/*
* Splice the writeback list onto a temporary list to avoid waiting on
* inodes that have started writeback after this point.
*
* Use rcu_read_lock() to keep the inodes around until we have a
* reference. s_inode_wblist_lock protects sb->s_inodes_wb as well as
* the local list because inodes can be dropped from either by writeback
* completion.
*/
rcu_read_lock();
spin_lock_irq(&sb->s_inode_wblist_lock);
list_splice_init(&sb->s_inodes_wb, &sync_list);
/*
* Data integrity sync. Must wait for all pages under writeback, because
* there may have been pages dirtied before our sync call, but which had
* writeout started before we write it out. In which case, the inode
* may not be on the dirty list, but we still have to wait for that
* writeout.
*/
while (!list_empty(&sync_list)) {
struct inode *inode = list_first_entry(&sync_list, struct inode,
i_wb_list);
struct address_space *mapping = inode->i_mapping;
/*
* Move each inode back to the wb list before we drop the lock
* to preserve consistency between i_wb_list and the mapping
* writeback tag. Writeback completion is responsible to remove
* the inode from either list once the writeback tag is cleared.
*/
list_move_tail(&inode->i_wb_list, &sb->s_inodes_wb);
/*
* The mapping can appear untagged while still on-list since we
* do not have the mapping lock. Skip it here, wb completion
* will remove it.
*/
if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
continue;
spin_unlock_irq(&sb->s_inode_wblist_lock);
spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
spin_unlock(&inode->i_lock);
spin_lock_irq(&sb->s_inode_wblist_lock);
continue;
}
__iget(inode);
spin_unlock(&inode->i_lock);
rcu_read_unlock();
/*
* We keep the error status of individual mapping so that
* applications can catch the writeback error using fsync(2).
* See filemap_fdatawait_keep_errors() for details.
*/
filemap_fdatawait_keep_errors(mapping);
cond_resched();
iput(inode);
rcu_read_lock();
spin_lock_irq(&sb->s_inode_wblist_lock);
}
spin_unlock_irq(&sb->s_inode_wblist_lock);
rcu_read_unlock();
mutex_unlock(&sb->s_sync_lock);
}
static void __writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr,
enum wb_reason reason, bool skip_if_busy)
{
struct backing_dev_info *bdi = sb->s_bdi;
DEFINE_WB_COMPLETION(done, bdi);
struct wb_writeback_work work = {
.sb = sb,
.sync_mode = WB_SYNC_NONE,
.tagged_writepages = 1,
.done = &done,
.nr_pages = nr,
.reason = reason,
};
if (!bdi_has_dirty_io(bdi) || bdi == &noop_backing_dev_info)
return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));
bdi_split_work_to_wbs(sb->s_bdi, &work, skip_if_busy);
wb_wait_for_completion(&done);
}
/**
* writeback_inodes_sb_nr - writeback dirty inodes from given super_block
* @sb: the superblock
* @nr: the number of pages to write
* @reason: reason why some writeback work initiated
*
* Start writeback on some inodes on this super_block. No guarantees are made
* on how many (if any) will be written, and this function does not wait
* for IO completion of submitted IO.
*/
void writeback_inodes_sb_nr(struct super_block *sb,
unsigned long nr,
enum wb_reason reason)
{
__writeback_inodes_sb_nr(sb, nr, reason, false);
}
EXPORT_SYMBOL(writeback_inodes_sb_nr);
/**
* writeback_inodes_sb - writeback dirty inodes from given super_block
* @sb: the superblock
* @reason: reason why some writeback work was initiated
*
* Start writeback on some inodes on this super_block. No guarantees are made
* on how many (if any) will be written, and this function does not wait
* for IO completion of submitted IO.
*/
void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
{
return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
}
EXPORT_SYMBOL(writeback_inodes_sb);
/**
* try_to_writeback_inodes_sb - try to start writeback if none underway
* @sb: the superblock
* @reason: reason why some writeback work was initiated
*
* Invoke __writeback_inodes_sb_nr if no writeback is currently underway.
*/
void try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
{
if (!down_read_trylock(&sb->s_umount))
return;
__writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason, true);
up_read(&sb->s_umount);
}
EXPORT_SYMBOL(try_to_writeback_inodes_sb);
/**
* sync_inodes_sb - sync sb inode pages
* @sb: the superblock
*
* This function writes and waits on any dirty inode belonging to this
* super_block.
*/
void sync_inodes_sb(struct super_block *sb)
{
struct backing_dev_info *bdi = sb->s_bdi;
DEFINE_WB_COMPLETION(done, bdi);
struct wb_writeback_work work = {
.sb = sb,
.sync_mode = WB_SYNC_ALL,
.nr_pages = LONG_MAX,
.range_cyclic = 0,
.done = &done,
.reason = WB_REASON_SYNC,
.for_sync = 1,
};
/*
* Can't skip on !bdi_has_dirty() because we should wait for !dirty
* inodes under writeback and I_DIRTY_TIME inodes ignored by
* bdi_has_dirty() need to be written out too.
*/
if (bdi == &noop_backing_dev_info)
return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));
/* protect against inode wb switch, see inode_switch_wbs_work_fn() */
bdi_down_write_wb_switch_rwsem(bdi);
bdi_split_work_to_wbs(bdi, &work, false);
wb_wait_for_completion(&done);
bdi_up_write_wb_switch_rwsem(bdi);
wait_sb_inodes(sb);
}
EXPORT_SYMBOL(sync_inodes_sb);
/**
* write_inode_now - write an inode to disk
* @inode: inode to write to disk
* @sync: whether the write should be synchronous or not
*
* This function commits an inode to disk immediately if it is dirty. This is
* primarily needed by knfsd.
*
* The caller must either have a ref on the inode or must have set I_WILL_FREE.
*/
int write_inode_now(struct inode *inode, int sync)
{
struct writeback_control wbc = {
.nr_to_write = LONG_MAX,
.sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE,
.range_start = 0,
.range_end = LLONG_MAX,
};
if (!mapping_can_writeback(inode->i_mapping))
wbc.nr_to_write = 0;
might_sleep();
return writeback_single_inode(inode, &wbc);
}
EXPORT_SYMBOL(write_inode_now);
/**
* sync_inode_metadata - write an inode to disk
* @inode: the inode to sync
* @wait: wait for I/O to complete.
*
* Write an inode to disk and adjust its dirty state after completion.
*
* Note: only writes the actual inode, no associated data or other metadata.
*/
int sync_inode_metadata(struct inode *inode, int wait)
{
struct writeback_control wbc = {
.sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE,
.nr_to_write = 0, /* metadata-only */
};
return writeback_single_inode(inode, &wbc);
}
EXPORT_SYMBOL(sync_inode_metadata);
| linux-master | fs/fs-writeback.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/sched/xacct.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/splice.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/fs.h>
#include <linux/dax.h>
#include <linux/overflow.h>
#include "internal.h"
#include <linux/uaccess.h>
#include <asm/unistd.h>
/*
* Performs necessary checks before doing a clone.
*
* Can adjust amount of bytes to clone via @req_count argument.
* Returns appropriate error code that caller should return or
* zero in case the clone should be allowed.
*/
static int generic_remap_checks(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t *req_count, unsigned int remap_flags)
{
struct inode *inode_in = file_in->f_mapping->host;
struct inode *inode_out = file_out->f_mapping->host;
uint64_t count = *req_count;
uint64_t bcount;
loff_t size_in, size_out;
loff_t bs = inode_out->i_sb->s_blocksize;
int ret;
/* The start of both ranges must be aligned to an fs block. */
if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs))
return -EINVAL;
/* Ensure offsets don't wrap. */
if (pos_in + count < pos_in || pos_out + count < pos_out)
return -EINVAL;
size_in = i_size_read(inode_in);
size_out = i_size_read(inode_out);
/* Dedupe requires both ranges to be within EOF. */
if ((remap_flags & REMAP_FILE_DEDUP) &&
(pos_in >= size_in || pos_in + count > size_in ||
pos_out >= size_out || pos_out + count > size_out))
return -EINVAL;
/* Ensure the infile range is within the infile. */
if (pos_in >= size_in)
return -EINVAL;
count = min(count, size_in - (uint64_t)pos_in);
ret = generic_write_check_limits(file_out, pos_out, &count);
if (ret)
return ret;
/*
* If the user wanted us to link to the infile's EOF, round up to the
* next block boundary for this check.
*
* Otherwise, make sure the count is also block-aligned, having
* already confirmed the starting offsets' block alignment.
*/
if (pos_in + count == size_in &&
(!(remap_flags & REMAP_FILE_DEDUP) || pos_out + count == size_out)) {
bcount = ALIGN(size_in, bs) - pos_in;
} else {
if (!IS_ALIGNED(count, bs))
count = ALIGN_DOWN(count, bs);
bcount = count;
}
/* Don't allow overlapped cloning within the same file. */
if (inode_in == inode_out &&
pos_out + bcount > pos_in &&
pos_out < pos_in + bcount)
return -EINVAL;
/*
* We shortened the request but the caller can't deal with that, so
* bounce the request back to userspace.
*/
if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN))
return -EINVAL;
*req_count = count;
return 0;
}
static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
bool write)
{
loff_t tmp;
if (unlikely(pos < 0 || len < 0))
return -EINVAL;
if (unlikely(check_add_overflow(pos, len, &tmp)))
return -EINVAL;
return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
}
/*
* Ensure that we don't remap a partial EOF block in the middle of something
* else. Assume that the offsets have already been checked for block
* alignment.
*
* For clone we only link a partial EOF block above or at the destination file's
* EOF. For deduplication we accept a partial EOF block only if it ends at the
* destination file's EOF (can not link it into the middle of a file).
*
* Shorten the request if possible.
*/
static int generic_remap_check_len(struct inode *inode_in,
struct inode *inode_out,
loff_t pos_out,
loff_t *len,
unsigned int remap_flags)
{
u64 blkmask = i_blocksize(inode_in) - 1;
loff_t new_len = *len;
if ((*len & blkmask) == 0)
return 0;
if (pos_out + *len < i_size_read(inode_out))
new_len &= ~blkmask;
if (new_len == *len)
return 0;
if (remap_flags & REMAP_FILE_CAN_SHORTEN) {
*len = new_len;
return 0;
}
return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL;
}
/* Read a page's worth of file data into the page cache. */
static struct folio *vfs_dedupe_get_folio(struct file *file, loff_t pos)
{
return read_mapping_folio(file->f_mapping, pos >> PAGE_SHIFT, file);
}
/*
* Lock two folios, ensuring that we lock in offset order if the folios
* are from the same file.
*/
static void vfs_lock_two_folios(struct folio *folio1, struct folio *folio2)
{
/* Always lock in order of increasing index. */
if (folio1->index > folio2->index)
swap(folio1, folio2);
folio_lock(folio1);
if (folio1 != folio2)
folio_lock(folio2);
}
/* Unlock two folios, being careful not to unlock the same folio twice. */
static void vfs_unlock_two_folios(struct folio *folio1, struct folio *folio2)
{
folio_unlock(folio1);
if (folio1 != folio2)
folio_unlock(folio2);
}
/*
* Compare extents of two files to see if they are the same.
* Caller must have locked both inodes to prevent write races.
*/
static int vfs_dedupe_file_range_compare(struct file *src, loff_t srcoff,
struct file *dest, loff_t dstoff,
loff_t len, bool *is_same)
{
bool same = true;
int error = -EINVAL;
while (len) {
struct folio *src_folio, *dst_folio;
void *src_addr, *dst_addr;
loff_t cmp_len = min(PAGE_SIZE - offset_in_page(srcoff),
PAGE_SIZE - offset_in_page(dstoff));
cmp_len = min(cmp_len, len);
if (cmp_len <= 0)
goto out_error;
src_folio = vfs_dedupe_get_folio(src, srcoff);
if (IS_ERR(src_folio)) {
error = PTR_ERR(src_folio);
goto out_error;
}
dst_folio = vfs_dedupe_get_folio(dest, dstoff);
if (IS_ERR(dst_folio)) {
error = PTR_ERR(dst_folio);
folio_put(src_folio);
goto out_error;
}
vfs_lock_two_folios(src_folio, dst_folio);
/*
* Now that we've locked both folios, make sure they're still
* mapped to the file data we're interested in. If not,
* someone is invalidating pages on us and we lose.
*/
if (!folio_test_uptodate(src_folio) || !folio_test_uptodate(dst_folio) ||
src_folio->mapping != src->f_mapping ||
dst_folio->mapping != dest->f_mapping) {
same = false;
goto unlock;
}
src_addr = kmap_local_folio(src_folio,
offset_in_folio(src_folio, srcoff));
dst_addr = kmap_local_folio(dst_folio,
offset_in_folio(dst_folio, dstoff));
flush_dcache_folio(src_folio);
flush_dcache_folio(dst_folio);
if (memcmp(src_addr, dst_addr, cmp_len))
same = false;
kunmap_local(dst_addr);
kunmap_local(src_addr);
unlock:
vfs_unlock_two_folios(src_folio, dst_folio);
folio_put(dst_folio);
folio_put(src_folio);
if (!same)
break;
srcoff += cmp_len;
dstoff += cmp_len;
len -= cmp_len;
}
*is_same = same;
return 0;
out_error:
return error;
}
/*
* Check that the two inodes are eligible for cloning, the ranges make
* sense, and then flush all dirty data. Caller must ensure that the
* inodes have been locked against any other modifications.
*
* If there's an error, then the usual negative error code is returned.
* Otherwise returns 0 with *len set to the request length.
*/
int
__generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t *len, unsigned int remap_flags,
const struct iomap_ops *dax_read_ops)
{
struct inode *inode_in = file_inode(file_in);
struct inode *inode_out = file_inode(file_out);
bool same_inode = (inode_in == inode_out);
int ret;
/* Don't touch certain kinds of inodes */
if (IS_IMMUTABLE(inode_out))
return -EPERM;
if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
return -ETXTBSY;
/* Don't reflink dirs, pipes, sockets... */
if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
return -EISDIR;
if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
return -EINVAL;
/* Zero length dedupe exits immediately; reflink goes to EOF. */
if (*len == 0) {
loff_t isize = i_size_read(inode_in);
if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize)
return 0;
if (pos_in > isize)
return -EINVAL;
*len = isize - pos_in;
if (*len == 0)
return 0;
}
/* Check that we don't violate system file offset limits. */
ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len,
remap_flags);
if (ret || *len == 0)
return ret;
/* Wait for the completion of any pending IOs on both files */
inode_dio_wait(inode_in);
if (!same_inode)
inode_dio_wait(inode_out);
ret = filemap_write_and_wait_range(inode_in->i_mapping,
pos_in, pos_in + *len - 1);
if (ret)
return ret;
ret = filemap_write_and_wait_range(inode_out->i_mapping,
pos_out, pos_out + *len - 1);
if (ret)
return ret;
/*
* Check that the extents are the same.
*/
if (remap_flags & REMAP_FILE_DEDUP) {
bool is_same = false;
if (!IS_DAX(inode_in))
ret = vfs_dedupe_file_range_compare(file_in, pos_in,
file_out, pos_out, *len, &is_same);
else if (dax_read_ops)
ret = dax_dedupe_file_range_compare(inode_in, pos_in,
inode_out, pos_out, *len, &is_same,
dax_read_ops);
else
return -EINVAL;
if (ret)
return ret;
if (!is_same)
return -EBADE;
}
ret = generic_remap_check_len(inode_in, inode_out, pos_out, len,
remap_flags);
if (ret || *len == 0)
return ret;
/* If can't alter the file contents, we're done. */
if (!(remap_flags & REMAP_FILE_DEDUP))
ret = file_modified(file_out);
return ret;
}
int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t *len, unsigned int remap_flags)
{
return __generic_remap_file_range_prep(file_in, pos_in, file_out,
pos_out, len, remap_flags, NULL);
}
EXPORT_SYMBOL(generic_remap_file_range_prep);
loff_t do_clone_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t len, unsigned int remap_flags)
{
loff_t ret;
WARN_ON_ONCE(remap_flags & REMAP_FILE_DEDUP);
if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
return -EXDEV;
ret = generic_file_rw_checks(file_in, file_out);
if (ret < 0)
return ret;
if (!file_in->f_op->remap_file_range)
return -EOPNOTSUPP;
ret = remap_verify_area(file_in, pos_in, len, false);
if (ret)
return ret;
ret = remap_verify_area(file_out, pos_out, len, true);
if (ret)
return ret;
ret = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out, len, remap_flags);
if (ret < 0)
return ret;
fsnotify_access(file_in);
fsnotify_modify(file_out);
return ret;
}
EXPORT_SYMBOL(do_clone_file_range);
loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t len, unsigned int remap_flags)
{
loff_t ret;
file_start_write(file_out);
ret = do_clone_file_range(file_in, pos_in, file_out, pos_out, len,
remap_flags);
file_end_write(file_out);
return ret;
}
EXPORT_SYMBOL(vfs_clone_file_range);
/* Check whether we are allowed to dedupe the destination file */
static bool allow_file_dedupe(struct file *file)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct inode *inode = file_inode(file);
if (capable(CAP_SYS_ADMIN))
return true;
if (file->f_mode & FMODE_WRITE)
return true;
if (vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode), current_fsuid()))
return true;
if (!inode_permission(idmap, inode, MAY_WRITE))
return true;
return false;
}
loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
struct file *dst_file, loff_t dst_pos,
loff_t len, unsigned int remap_flags)
{
loff_t ret;
WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
REMAP_FILE_CAN_SHORTEN));
ret = mnt_want_write_file(dst_file);
if (ret)
return ret;
/*
* This is redundant if called from vfs_dedupe_file_range(), but other
* callers need it and it's not performance sesitive...
*/
ret = remap_verify_area(src_file, src_pos, len, false);
if (ret)
goto out_drop_write;
ret = remap_verify_area(dst_file, dst_pos, len, true);
if (ret)
goto out_drop_write;
ret = -EPERM;
if (!allow_file_dedupe(dst_file))
goto out_drop_write;
ret = -EXDEV;
if (file_inode(src_file)->i_sb != file_inode(dst_file)->i_sb)
goto out_drop_write;
ret = -EISDIR;
if (S_ISDIR(file_inode(dst_file)->i_mode))
goto out_drop_write;
ret = -EINVAL;
if (!dst_file->f_op->remap_file_range)
goto out_drop_write;
if (len == 0) {
ret = 0;
goto out_drop_write;
}
ret = dst_file->f_op->remap_file_range(src_file, src_pos, dst_file,
dst_pos, len, remap_flags | REMAP_FILE_DEDUP);
out_drop_write:
mnt_drop_write_file(dst_file);
return ret;
}
EXPORT_SYMBOL(vfs_dedupe_file_range_one);
int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
{
struct file_dedupe_range_info *info;
struct inode *src = file_inode(file);
u64 off;
u64 len;
int i;
int ret;
u16 count = same->dest_count;
loff_t deduped;
if (!(file->f_mode & FMODE_READ))
return -EINVAL;
if (same->reserved1 || same->reserved2)
return -EINVAL;
off = same->src_offset;
len = same->src_length;
if (S_ISDIR(src->i_mode))
return -EISDIR;
if (!S_ISREG(src->i_mode))
return -EINVAL;
if (!file->f_op->remap_file_range)
return -EOPNOTSUPP;
ret = remap_verify_area(file, off, len, false);
if (ret < 0)
return ret;
ret = 0;
if (off + len > i_size_read(src))
return -EINVAL;
/* Arbitrary 1G limit on a single dedupe request, can be raised. */
len = min_t(u64, len, 1 << 30);
/* pre-format output fields to sane values */
for (i = 0; i < count; i++) {
same->info[i].bytes_deduped = 0ULL;
same->info[i].status = FILE_DEDUPE_RANGE_SAME;
}
for (i = 0, info = same->info; i < count; i++, info++) {
struct fd dst_fd = fdget(info->dest_fd);
struct file *dst_file = dst_fd.file;
if (!dst_file) {
info->status = -EBADF;
goto next_loop;
}
if (info->reserved) {
info->status = -EINVAL;
goto next_fdput;
}
deduped = vfs_dedupe_file_range_one(file, off, dst_file,
info->dest_offset, len,
REMAP_FILE_CAN_SHORTEN);
if (deduped == -EBADE)
info->status = FILE_DEDUPE_RANGE_DIFFERS;
else if (deduped < 0)
info->status = deduped;
else
info->bytes_deduped = len;
next_fdput:
fdput(dst_fd);
next_loop:
if (fatal_signal_pending(current))
break;
}
return ret;
}
EXPORT_SYMBOL(vfs_dedupe_file_range);
| linux-master | fs/remap_range.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* fs/dcache.c
*
* Complete reimplementation
* (C) 1997 Thomas Schoebel-Theuer,
* with heavy changes by Linus Torvalds
*/
/*
* Notes on the allocation strategy:
*
* The dcache is a master of the icache - whenever a dcache entry
* exists, the inode will always exist. "iput()" is done either when
* the dcache entry is deleted or garbage collected.
*/
#include <linux/ratelimit.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/fscrypt.h>
#include <linux/fsnotify.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/cache.h>
#include <linux/export.h>
#include <linux/security.h>
#include <linux/seqlock.h>
#include <linux/memblock.h>
#include <linux/bit_spinlock.h>
#include <linux/rculist_bl.h>
#include <linux/list_lru.h>
#include "internal.h"
#include "mount.h"
/*
* Usage:
* dcache->d_inode->i_lock protects:
* - i_dentry, d_u.d_alias, d_inode of aliases
* dcache_hash_bucket lock protects:
* - the dcache hash table
* s_roots bl list spinlock protects:
* - the s_roots list (see __d_drop)
* dentry->d_sb->s_dentry_lru_lock protects:
* - the dcache lru lists and counters
* d_lock protects:
* - d_flags
* - d_name
* - d_lru
* - d_count
* - d_unhashed()
* - d_parent and d_subdirs
* - childrens' d_child and d_parent
* - d_u.d_alias, d_inode
*
* Ordering:
* dentry->d_inode->i_lock
* dentry->d_lock
* dentry->d_sb->s_dentry_lru_lock
* dcache_hash_bucket lock
* s_roots lock
*
* If there is an ancestor relationship:
* dentry->d_parent->...->d_parent->d_lock
* ...
* dentry->d_parent->d_lock
* dentry->d_lock
*
* If no ancestor relationship:
* arbitrary, since it's serialized on rename_lock
*/
int sysctl_vfs_cache_pressure __read_mostly = 100;
EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
EXPORT_SYMBOL(rename_lock);
static struct kmem_cache *dentry_cache __read_mostly;
const struct qstr empty_name = QSTR_INIT("", 0);
EXPORT_SYMBOL(empty_name);
const struct qstr slash_name = QSTR_INIT("/", 1);
EXPORT_SYMBOL(slash_name);
const struct qstr dotdot_name = QSTR_INIT("..", 2);
EXPORT_SYMBOL(dotdot_name);
/*
* This is the single most critical data structure when it comes
* to the dcache: the hashtable for lookups. Somebody should try
* to make this good - I've just made it work.
*
* This hash-function tries to avoid losing too many bits of hash
* information, yet avoid using a prime hash-size or similar.
*/
static unsigned int d_hash_shift __read_mostly;
static struct hlist_bl_head *dentry_hashtable __read_mostly;
static inline struct hlist_bl_head *d_hash(unsigned int hash)
{
return dentry_hashtable + (hash >> d_hash_shift);
}
#define IN_LOOKUP_SHIFT 10
static struct hlist_bl_head in_lookup_hashtable[1 << IN_LOOKUP_SHIFT];
static inline struct hlist_bl_head *in_lookup_hash(const struct dentry *parent,
unsigned int hash)
{
hash += (unsigned long) parent / L1_CACHE_BYTES;
return in_lookup_hashtable + hash_32(hash, IN_LOOKUP_SHIFT);
}
struct dentry_stat_t {
long nr_dentry;
long nr_unused;
long age_limit; /* age in seconds */
long want_pages; /* pages requested by system */
long nr_negative; /* # of unused negative dentries */
long dummy; /* Reserved for future use */
};
static DEFINE_PER_CPU(long, nr_dentry);
static DEFINE_PER_CPU(long, nr_dentry_unused);
static DEFINE_PER_CPU(long, nr_dentry_negative);
#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
/* Statistics gathering. */
static struct dentry_stat_t dentry_stat = {
.age_limit = 45,
};
/*
* Here we resort to our own counters instead of using generic per-cpu counters
* for consistency with what the vfs inode code does. We are expected to harvest
* better code and performance by having our own specialized counters.
*
* Please note that the loop is done over all possible CPUs, not over all online
* CPUs. The reason for this is that we don't want to play games with CPUs going
* on and off. If one of them goes off, we will just keep their counters.
*
* glommer: See cffbc8a for details, and if you ever intend to change this,
* please update all vfs counters to match.
*/
static long get_nr_dentry(void)
{
int i;
long sum = 0;
for_each_possible_cpu(i)
sum += per_cpu(nr_dentry, i);
return sum < 0 ? 0 : sum;
}
static long get_nr_dentry_unused(void)
{
int i;
long sum = 0;
for_each_possible_cpu(i)
sum += per_cpu(nr_dentry_unused, i);
return sum < 0 ? 0 : sum;
}
static long get_nr_dentry_negative(void)
{
int i;
long sum = 0;
for_each_possible_cpu(i)
sum += per_cpu(nr_dentry_negative, i);
return sum < 0 ? 0 : sum;
}
static int proc_nr_dentry(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
dentry_stat.nr_dentry = get_nr_dentry();
dentry_stat.nr_unused = get_nr_dentry_unused();
dentry_stat.nr_negative = get_nr_dentry_negative();
return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
}
static struct ctl_table fs_dcache_sysctls[] = {
{
.procname = "dentry-state",
.data = &dentry_stat,
.maxlen = 6*sizeof(long),
.mode = 0444,
.proc_handler = proc_nr_dentry,
},
{ }
};
static int __init init_fs_dcache_sysctls(void)
{
register_sysctl_init("fs", fs_dcache_sysctls);
return 0;
}
fs_initcall(init_fs_dcache_sysctls);
#endif
/*
* Compare 2 name strings, return 0 if they match, otherwise non-zero.
* The strings are both count bytes long, and count is non-zero.
*/
#ifdef CONFIG_DCACHE_WORD_ACCESS
#include <asm/word-at-a-time.h>
/*
* NOTE! 'cs' and 'scount' come from a dentry, so it has a
* aligned allocation for this particular component. We don't
* strictly need the load_unaligned_zeropad() safety, but it
* doesn't hurt either.
*
* In contrast, 'ct' and 'tcount' can be from a pathname, and do
* need the careful unaligned handling.
*/
static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
{
unsigned long a,b,mask;
for (;;) {
a = read_word_at_a_time(cs);
b = load_unaligned_zeropad(ct);
if (tcount < sizeof(unsigned long))
break;
if (unlikely(a != b))
return 1;
cs += sizeof(unsigned long);
ct += sizeof(unsigned long);
tcount -= sizeof(unsigned long);
if (!tcount)
return 0;
}
mask = bytemask_from_count(tcount);
return unlikely(!!((a ^ b) & mask));
}
#else
static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
{
do {
if (*cs != *ct)
return 1;
cs++;
ct++;
tcount--;
} while (tcount);
return 0;
}
#endif
static inline int dentry_cmp(const struct dentry *dentry, const unsigned char *ct, unsigned tcount)
{
/*
* Be careful about RCU walk racing with rename:
* use 'READ_ONCE' to fetch the name pointer.
*
* NOTE! Even if a rename will mean that the length
* was not loaded atomically, we don't care. The
* RCU walk will check the sequence count eventually,
* and catch it. And we won't overrun the buffer,
* because we're reading the name pointer atomically,
* and a dentry name is guaranteed to be properly
* terminated with a NUL byte.
*
* End result: even if 'len' is wrong, we'll exit
* early because the data cannot match (there can
* be no NUL in the ct/tcount data)
*/
const unsigned char *cs = READ_ONCE(dentry->d_name.name);
return dentry_string_cmp(cs, ct, tcount);
}
struct external_name {
union {
atomic_t count;
struct rcu_head head;
} u;
unsigned char name[];
};
static inline struct external_name *external_name(struct dentry *dentry)
{
return container_of(dentry->d_name.name, struct external_name, name[0]);
}
static void __d_free(struct rcu_head *head)
{
struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
kmem_cache_free(dentry_cache, dentry);
}
static void __d_free_external(struct rcu_head *head)
{
struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
kfree(external_name(dentry));
kmem_cache_free(dentry_cache, dentry);
}
static inline int dname_external(const struct dentry *dentry)
{
return dentry->d_name.name != dentry->d_iname;
}
void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
name->name = dentry->d_name;
if (unlikely(dname_external(dentry))) {
atomic_inc(&external_name(dentry)->u.count);
} else {
memcpy(name->inline_name, dentry->d_iname,
dentry->d_name.len + 1);
name->name.name = name->inline_name;
}
spin_unlock(&dentry->d_lock);
}
EXPORT_SYMBOL(take_dentry_name_snapshot);
void release_dentry_name_snapshot(struct name_snapshot *name)
{
if (unlikely(name->name.name != name->inline_name)) {
struct external_name *p;
p = container_of(name->name.name, struct external_name, name[0]);
if (unlikely(atomic_dec_and_test(&p->u.count)))
kfree_rcu(p, u.head);
}
}
EXPORT_SYMBOL(release_dentry_name_snapshot);
static inline void __d_set_inode_and_type(struct dentry *dentry,
struct inode *inode,
unsigned type_flags)
{
unsigned flags;
dentry->d_inode = inode;
flags = READ_ONCE(dentry->d_flags);
flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
flags |= type_flags;
smp_store_release(&dentry->d_flags, flags);
}
static inline void __d_clear_type_and_inode(struct dentry *dentry)
{
unsigned flags = READ_ONCE(dentry->d_flags);
flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
WRITE_ONCE(dentry->d_flags, flags);
dentry->d_inode = NULL;
if (dentry->d_flags & DCACHE_LRU_LIST)
this_cpu_inc(nr_dentry_negative);
}
static void dentry_free(struct dentry *dentry)
{
WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
if (unlikely(dname_external(dentry))) {
struct external_name *p = external_name(dentry);
if (likely(atomic_dec_and_test(&p->u.count))) {
call_rcu(&dentry->d_u.d_rcu, __d_free_external);
return;
}
}
/* if dentry was never visible to RCU, immediate free is OK */
if (dentry->d_flags & DCACHE_NORCU)
__d_free(&dentry->d_u.d_rcu);
else
call_rcu(&dentry->d_u.d_rcu, __d_free);
}
/*
* Release the dentry's inode, using the filesystem
* d_iput() operation if defined.
*/
static void dentry_unlink_inode(struct dentry * dentry)
__releases(dentry->d_lock)
__releases(dentry->d_inode->i_lock)
{
struct inode *inode = dentry->d_inode;
raw_write_seqcount_begin(&dentry->d_seq);
__d_clear_type_and_inode(dentry);
hlist_del_init(&dentry->d_u.d_alias);
raw_write_seqcount_end(&dentry->d_seq);
spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
if (!inode->i_nlink)
fsnotify_inoderemove(inode);
if (dentry->d_op && dentry->d_op->d_iput)
dentry->d_op->d_iput(dentry, inode);
else
iput(inode);
}
/*
* The DCACHE_LRU_LIST bit is set whenever the 'd_lru' entry
* is in use - which includes both the "real" per-superblock
* LRU list _and_ the DCACHE_SHRINK_LIST use.
*
* The DCACHE_SHRINK_LIST bit is set whenever the dentry is
* on the shrink list (ie not on the superblock LRU list).
*
* The per-cpu "nr_dentry_unused" counters are updated with
* the DCACHE_LRU_LIST bit.
*
* The per-cpu "nr_dentry_negative" counters are only updated
* when deleted from or added to the per-superblock LRU list, not
* from/to the shrink list. That is to avoid an unneeded dec/inc
* pair when moving from LRU to shrink list in select_collect().
*
* These helper functions make sure we always follow the
* rules. d_lock must be held by the caller.
*/
#define D_FLAG_VERIFY(dentry,x) WARN_ON_ONCE(((dentry)->d_flags & (DCACHE_LRU_LIST | DCACHE_SHRINK_LIST)) != (x))
static void d_lru_add(struct dentry *dentry)
{
D_FLAG_VERIFY(dentry, 0);
dentry->d_flags |= DCACHE_LRU_LIST;
this_cpu_inc(nr_dentry_unused);
if (d_is_negative(dentry))
this_cpu_inc(nr_dentry_negative);
WARN_ON_ONCE(!list_lru_add(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
}
static void d_lru_del(struct dentry *dentry)
{
D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
dentry->d_flags &= ~DCACHE_LRU_LIST;
this_cpu_dec(nr_dentry_unused);
if (d_is_negative(dentry))
this_cpu_dec(nr_dentry_negative);
WARN_ON_ONCE(!list_lru_del(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
}
static void d_shrink_del(struct dentry *dentry)
{
D_FLAG_VERIFY(dentry, DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
list_del_init(&dentry->d_lru);
dentry->d_flags &= ~(DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
this_cpu_dec(nr_dentry_unused);
}
static void d_shrink_add(struct dentry *dentry, struct list_head *list)
{
D_FLAG_VERIFY(dentry, 0);
list_add(&dentry->d_lru, list);
dentry->d_flags |= DCACHE_SHRINK_LIST | DCACHE_LRU_LIST;
this_cpu_inc(nr_dentry_unused);
}
/*
* These can only be called under the global LRU lock, ie during the
* callback for freeing the LRU list. "isolate" removes it from the
* LRU lists entirely, while shrink_move moves it to the indicated
* private list.
*/
static void d_lru_isolate(struct list_lru_one *lru, struct dentry *dentry)
{
D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
dentry->d_flags &= ~DCACHE_LRU_LIST;
this_cpu_dec(nr_dentry_unused);
if (d_is_negative(dentry))
this_cpu_dec(nr_dentry_negative);
list_lru_isolate(lru, &dentry->d_lru);
}
static void d_lru_shrink_move(struct list_lru_one *lru, struct dentry *dentry,
struct list_head *list)
{
D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
dentry->d_flags |= DCACHE_SHRINK_LIST;
if (d_is_negative(dentry))
this_cpu_dec(nr_dentry_negative);
list_lru_isolate_move(lru, &dentry->d_lru, list);
}
static void ___d_drop(struct dentry *dentry)
{
struct hlist_bl_head *b;
/*
* Hashed dentries are normally on the dentry hashtable,
* with the exception of those newly allocated by
* d_obtain_root, which are always IS_ROOT:
*/
if (unlikely(IS_ROOT(dentry)))
b = &dentry->d_sb->s_roots;
else
b = d_hash(dentry->d_name.hash);
hlist_bl_lock(b);
__hlist_bl_del(&dentry->d_hash);
hlist_bl_unlock(b);
}
void __d_drop(struct dentry *dentry)
{
if (!d_unhashed(dentry)) {
___d_drop(dentry);
dentry->d_hash.pprev = NULL;
write_seqcount_invalidate(&dentry->d_seq);
}
}
EXPORT_SYMBOL(__d_drop);
/**
* d_drop - drop a dentry
* @dentry: dentry to drop
*
* d_drop() unhashes the entry from the parent dentry hashes, so that it won't
* be found through a VFS lookup any more. Note that this is different from
* deleting the dentry - d_delete will try to mark the dentry negative if
* possible, giving a successful _negative_ lookup, while d_drop will
* just make the cache lookup fail.
*
* d_drop() is used mainly for stuff that wants to invalidate a dentry for some
* reason (NFS timeouts or autofs deletes).
*
* __d_drop requires dentry->d_lock
*
* ___d_drop doesn't mark dentry as "unhashed"
* (dentry->d_hash.pprev will be LIST_POISON2, not NULL).
*/
void d_drop(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
}
EXPORT_SYMBOL(d_drop);
static inline void dentry_unlist(struct dentry *dentry, struct dentry *parent)
{
struct dentry *next;
/*
* Inform d_walk() and shrink_dentry_list() that we are no longer
* attached to the dentry tree
*/
dentry->d_flags |= DCACHE_DENTRY_KILLED;
if (unlikely(list_empty(&dentry->d_child)))
return;
__list_del_entry(&dentry->d_child);
/*
* Cursors can move around the list of children. While we'd been
* a normal list member, it didn't matter - ->d_child.next would've
* been updated. However, from now on it won't be and for the
* things like d_walk() it might end up with a nasty surprise.
* Normally d_walk() doesn't care about cursors moving around -
* ->d_lock on parent prevents that and since a cursor has no children
* of its own, we get through it without ever unlocking the parent.
* There is one exception, though - if we ascend from a child that
* gets killed as soon as we unlock it, the next sibling is found
* using the value left in its ->d_child.next. And if _that_
* pointed to a cursor, and cursor got moved (e.g. by lseek())
* before d_walk() regains parent->d_lock, we'll end up skipping
* everything the cursor had been moved past.
*
* Solution: make sure that the pointer left behind in ->d_child.next
* points to something that won't be moving around. I.e. skip the
* cursors.
*/
while (dentry->d_child.next != &parent->d_subdirs) {
next = list_entry(dentry->d_child.next, struct dentry, d_child);
if (likely(!(next->d_flags & DCACHE_DENTRY_CURSOR)))
break;
dentry->d_child.next = next->d_child.next;
}
}
static void __dentry_kill(struct dentry *dentry)
{
struct dentry *parent = NULL;
bool can_free = true;
if (!IS_ROOT(dentry))
parent = dentry->d_parent;
/*
* The dentry is now unrecoverably dead to the world.
*/
lockref_mark_dead(&dentry->d_lockref);
/*
* inform the fs via d_prune that this dentry is about to be
* unhashed and destroyed.
*/
if (dentry->d_flags & DCACHE_OP_PRUNE)
dentry->d_op->d_prune(dentry);
if (dentry->d_flags & DCACHE_LRU_LIST) {
if (!(dentry->d_flags & DCACHE_SHRINK_LIST))
d_lru_del(dentry);
}
/* if it was on the hash then remove it */
__d_drop(dentry);
dentry_unlist(dentry, parent);
if (parent)
spin_unlock(&parent->d_lock);
if (dentry->d_inode)
dentry_unlink_inode(dentry);
else
spin_unlock(&dentry->d_lock);
this_cpu_dec(nr_dentry);
if (dentry->d_op && dentry->d_op->d_release)
dentry->d_op->d_release(dentry);
spin_lock(&dentry->d_lock);
if (dentry->d_flags & DCACHE_SHRINK_LIST) {
dentry->d_flags |= DCACHE_MAY_FREE;
can_free = false;
}
spin_unlock(&dentry->d_lock);
if (likely(can_free))
dentry_free(dentry);
cond_resched();
}
static struct dentry *__lock_parent(struct dentry *dentry)
{
struct dentry *parent;
rcu_read_lock();
spin_unlock(&dentry->d_lock);
again:
parent = READ_ONCE(dentry->d_parent);
spin_lock(&parent->d_lock);
/*
* We can't blindly lock dentry until we are sure
* that we won't violate the locking order.
* Any changes of dentry->d_parent must have
* been done with parent->d_lock held, so
* spin_lock() above is enough of a barrier
* for checking if it's still our child.
*/
if (unlikely(parent != dentry->d_parent)) {
spin_unlock(&parent->d_lock);
goto again;
}
rcu_read_unlock();
if (parent != dentry)
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
else
parent = NULL;
return parent;
}
static inline struct dentry *lock_parent(struct dentry *dentry)
{
struct dentry *parent = dentry->d_parent;
if (IS_ROOT(dentry))
return NULL;
if (likely(spin_trylock(&parent->d_lock)))
return parent;
return __lock_parent(dentry);
}
static inline bool retain_dentry(struct dentry *dentry)
{
WARN_ON(d_in_lookup(dentry));
/* Unreachable? Get rid of it */
if (unlikely(d_unhashed(dentry)))
return false;
if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
return false;
if (unlikely(dentry->d_flags & DCACHE_OP_DELETE)) {
if (dentry->d_op->d_delete(dentry))
return false;
}
if (unlikely(dentry->d_flags & DCACHE_DONTCACHE))
return false;
/* retain; LRU fodder */
dentry->d_lockref.count--;
if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST)))
d_lru_add(dentry);
else if (unlikely(!(dentry->d_flags & DCACHE_REFERENCED)))
dentry->d_flags |= DCACHE_REFERENCED;
return true;
}
void d_mark_dontcache(struct inode *inode)
{
struct dentry *de;
spin_lock(&inode->i_lock);
hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) {
spin_lock(&de->d_lock);
de->d_flags |= DCACHE_DONTCACHE;
spin_unlock(&de->d_lock);
}
inode->i_state |= I_DONTCACHE;
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(d_mark_dontcache);
/*
* Finish off a dentry we've decided to kill.
* dentry->d_lock must be held, returns with it unlocked.
* Returns dentry requiring refcount drop, or NULL if we're done.
*/
static struct dentry *dentry_kill(struct dentry *dentry)
__releases(dentry->d_lock)
{
struct inode *inode = dentry->d_inode;
struct dentry *parent = NULL;
if (inode && unlikely(!spin_trylock(&inode->i_lock)))
goto slow_positive;
if (!IS_ROOT(dentry)) {
parent = dentry->d_parent;
if (unlikely(!spin_trylock(&parent->d_lock))) {
parent = __lock_parent(dentry);
if (likely(inode || !dentry->d_inode))
goto got_locks;
/* negative that became positive */
if (parent)
spin_unlock(&parent->d_lock);
inode = dentry->d_inode;
goto slow_positive;
}
}
__dentry_kill(dentry);
return parent;
slow_positive:
spin_unlock(&dentry->d_lock);
spin_lock(&inode->i_lock);
spin_lock(&dentry->d_lock);
parent = lock_parent(dentry);
got_locks:
if (unlikely(dentry->d_lockref.count != 1)) {
dentry->d_lockref.count--;
} else if (likely(!retain_dentry(dentry))) {
__dentry_kill(dentry);
return parent;
}
/* we are keeping it, after all */
if (inode)
spin_unlock(&inode->i_lock);
if (parent)
spin_unlock(&parent->d_lock);
spin_unlock(&dentry->d_lock);
return NULL;
}
/*
* Try to do a lockless dput(), and return whether that was successful.
*
* If unsuccessful, we return false, having already taken the dentry lock.
*
* The caller needs to hold the RCU read lock, so that the dentry is
* guaranteed to stay around even if the refcount goes down to zero!
*/
static inline bool fast_dput(struct dentry *dentry)
{
int ret;
unsigned int d_flags;
/*
* If we have a d_op->d_delete() operation, we sould not
* let the dentry count go to zero, so use "put_or_lock".
*/
if (unlikely(dentry->d_flags & DCACHE_OP_DELETE))
return lockref_put_or_lock(&dentry->d_lockref);
/*
* .. otherwise, we can try to just decrement the
* lockref optimistically.
*/
ret = lockref_put_return(&dentry->d_lockref);
/*
* If the lockref_put_return() failed due to the lock being held
* by somebody else, the fast path has failed. We will need to
* get the lock, and then check the count again.
*/
if (unlikely(ret < 0)) {
spin_lock(&dentry->d_lock);
if (dentry->d_lockref.count > 1) {
dentry->d_lockref.count--;
spin_unlock(&dentry->d_lock);
return true;
}
return false;
}
/*
* If we weren't the last ref, we're done.
*/
if (ret)
return true;
/*
* Careful, careful. The reference count went down
* to zero, but we don't hold the dentry lock, so
* somebody else could get it again, and do another
* dput(), and we need to not race with that.
*
* However, there is a very special and common case
* where we don't care, because there is nothing to
* do: the dentry is still hashed, it does not have
* a 'delete' op, and it's referenced and already on
* the LRU list.
*
* NOTE! Since we aren't locked, these values are
* not "stable". However, it is sufficient that at
* some point after we dropped the reference the
* dentry was hashed and the flags had the proper
* value. Other dentry users may have re-gotten
* a reference to the dentry and change that, but
* our work is done - we can leave the dentry
* around with a zero refcount.
*
* Nevertheless, there are two cases that we should kill
* the dentry anyway.
* 1. free disconnected dentries as soon as their refcount
* reached zero.
* 2. free dentries if they should not be cached.
*/
smp_rmb();
d_flags = READ_ONCE(dentry->d_flags);
d_flags &= DCACHE_REFERENCED | DCACHE_LRU_LIST |
DCACHE_DISCONNECTED | DCACHE_DONTCACHE;
/* Nothing to do? Dropping the reference was all we needed? */
if (d_flags == (DCACHE_REFERENCED | DCACHE_LRU_LIST) && !d_unhashed(dentry))
return true;
/*
* Not the fast normal case? Get the lock. We've already decremented
* the refcount, but we'll need to re-check the situation after
* getting the lock.
*/
spin_lock(&dentry->d_lock);
/*
* Did somebody else grab a reference to it in the meantime, and
* we're no longer the last user after all? Alternatively, somebody
* else could have killed it and marked it dead. Either way, we
* don't need to do anything else.
*/
if (dentry->d_lockref.count) {
spin_unlock(&dentry->d_lock);
return true;
}
/*
* Re-get the reference we optimistically dropped. We hold the
* lock, and we just tested that it was zero, so we can just
* set it to 1.
*/
dentry->d_lockref.count = 1;
return false;
}
/*
* This is dput
*
* This is complicated by the fact that we do not want to put
* dentries that are no longer on any hash chain on the unused
* list: we'd much rather just get rid of them immediately.
*
* However, that implies that we have to traverse the dentry
* tree upwards to the parents which might _also_ now be
* scheduled for deletion (it may have been only waiting for
* its last child to go away).
*
* This tail recursion is done by hand as we don't want to depend
* on the compiler to always get this right (gcc generally doesn't).
* Real recursion would eat up our stack space.
*/
/*
* dput - release a dentry
* @dentry: dentry to release
*
* Release a dentry. This will drop the usage count and if appropriate
* call the dentry unlink method as well as removing it from the queues and
* releasing its resources. If the parent dentries were scheduled for release
* they too may now get deleted.
*/
void dput(struct dentry *dentry)
{
while (dentry) {
might_sleep();
rcu_read_lock();
if (likely(fast_dput(dentry))) {
rcu_read_unlock();
return;
}
/* Slow case: now with the dentry lock held */
rcu_read_unlock();
if (likely(retain_dentry(dentry))) {
spin_unlock(&dentry->d_lock);
return;
}
dentry = dentry_kill(dentry);
}
}
EXPORT_SYMBOL(dput);
static void __dput_to_list(struct dentry *dentry, struct list_head *list)
__must_hold(&dentry->d_lock)
{
if (dentry->d_flags & DCACHE_SHRINK_LIST) {
/* let the owner of the list it's on deal with it */
--dentry->d_lockref.count;
} else {
if (dentry->d_flags & DCACHE_LRU_LIST)
d_lru_del(dentry);
if (!--dentry->d_lockref.count)
d_shrink_add(dentry, list);
}
}
void dput_to_list(struct dentry *dentry, struct list_head *list)
{
rcu_read_lock();
if (likely(fast_dput(dentry))) {
rcu_read_unlock();
return;
}
rcu_read_unlock();
if (!retain_dentry(dentry))
__dput_to_list(dentry, list);
spin_unlock(&dentry->d_lock);
}
/* This must be called with d_lock held */
static inline void __dget_dlock(struct dentry *dentry)
{
dentry->d_lockref.count++;
}
static inline void __dget(struct dentry *dentry)
{
lockref_get(&dentry->d_lockref);
}
struct dentry *dget_parent(struct dentry *dentry)
{
int gotref;
struct dentry *ret;
unsigned seq;
/*
* Do optimistic parent lookup without any
* locking.
*/
rcu_read_lock();
seq = raw_seqcount_begin(&dentry->d_seq);
ret = READ_ONCE(dentry->d_parent);
gotref = lockref_get_not_zero(&ret->d_lockref);
rcu_read_unlock();
if (likely(gotref)) {
if (!read_seqcount_retry(&dentry->d_seq, seq))
return ret;
dput(ret);
}
repeat:
/*
* Don't need rcu_dereference because we re-check it was correct under
* the lock.
*/
rcu_read_lock();
ret = dentry->d_parent;
spin_lock(&ret->d_lock);
if (unlikely(ret != dentry->d_parent)) {
spin_unlock(&ret->d_lock);
rcu_read_unlock();
goto repeat;
}
rcu_read_unlock();
BUG_ON(!ret->d_lockref.count);
ret->d_lockref.count++;
spin_unlock(&ret->d_lock);
return ret;
}
EXPORT_SYMBOL(dget_parent);
static struct dentry * __d_find_any_alias(struct inode *inode)
{
struct dentry *alias;
if (hlist_empty(&inode->i_dentry))
return NULL;
alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
__dget(alias);
return alias;
}
/**
* d_find_any_alias - find any alias for a given inode
* @inode: inode to find an alias for
*
* If any aliases exist for the given inode, take and return a
* reference for one of them. If no aliases exist, return %NULL.
*/
struct dentry *d_find_any_alias(struct inode *inode)
{
struct dentry *de;
spin_lock(&inode->i_lock);
de = __d_find_any_alias(inode);
spin_unlock(&inode->i_lock);
return de;
}
EXPORT_SYMBOL(d_find_any_alias);
static struct dentry *__d_find_alias(struct inode *inode)
{
struct dentry *alias;
if (S_ISDIR(inode->i_mode))
return __d_find_any_alias(inode);
hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
spin_lock(&alias->d_lock);
if (!d_unhashed(alias)) {
__dget_dlock(alias);
spin_unlock(&alias->d_lock);
return alias;
}
spin_unlock(&alias->d_lock);
}
return NULL;
}
/**
* d_find_alias - grab a hashed alias of inode
* @inode: inode in question
*
* If inode has a hashed alias, or is a directory and has any alias,
* acquire the reference to alias and return it. Otherwise return NULL.
* Notice that if inode is a directory there can be only one alias and
* it can be unhashed only if it has no children, or if it is the root
* of a filesystem, or if the directory was renamed and d_revalidate
* was the first vfs operation to notice.
*
* If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
* any other hashed alias over that one.
*/
struct dentry *d_find_alias(struct inode *inode)
{
struct dentry *de = NULL;
if (!hlist_empty(&inode->i_dentry)) {
spin_lock(&inode->i_lock);
de = __d_find_alias(inode);
spin_unlock(&inode->i_lock);
}
return de;
}
EXPORT_SYMBOL(d_find_alias);
/*
* Caller MUST be holding rcu_read_lock() and be guaranteed
* that inode won't get freed until rcu_read_unlock().
*/
struct dentry *d_find_alias_rcu(struct inode *inode)
{
struct hlist_head *l = &inode->i_dentry;
struct dentry *de = NULL;
spin_lock(&inode->i_lock);
// ->i_dentry and ->i_rcu are colocated, but the latter won't be
// used without having I_FREEING set, which means no aliases left
if (likely(!(inode->i_state & I_FREEING) && !hlist_empty(l))) {
if (S_ISDIR(inode->i_mode)) {
de = hlist_entry(l->first, struct dentry, d_u.d_alias);
} else {
hlist_for_each_entry(de, l, d_u.d_alias)
if (!d_unhashed(de))
break;
}
}
spin_unlock(&inode->i_lock);
return de;
}
/*
* Try to kill dentries associated with this inode.
* WARNING: you must own a reference to inode.
*/
void d_prune_aliases(struct inode *inode)
{
struct dentry *dentry;
restart:
spin_lock(&inode->i_lock);
hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
spin_lock(&dentry->d_lock);
if (!dentry->d_lockref.count) {
struct dentry *parent = lock_parent(dentry);
if (likely(!dentry->d_lockref.count)) {
__dentry_kill(dentry);
dput(parent);
goto restart;
}
if (parent)
spin_unlock(&parent->d_lock);
}
spin_unlock(&dentry->d_lock);
}
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(d_prune_aliases);
/*
* Lock a dentry from shrink list.
* Called under rcu_read_lock() and dentry->d_lock; the former
* guarantees that nothing we access will be freed under us.
* Note that dentry is *not* protected from concurrent dentry_kill(),
* d_delete(), etc.
*
* Return false if dentry has been disrupted or grabbed, leaving
* the caller to kick it off-list. Otherwise, return true and have
* that dentry's inode and parent both locked.
*/
static bool shrink_lock_dentry(struct dentry *dentry)
{
struct inode *inode;
struct dentry *parent;
if (dentry->d_lockref.count)
return false;
inode = dentry->d_inode;
if (inode && unlikely(!spin_trylock(&inode->i_lock))) {
spin_unlock(&dentry->d_lock);
spin_lock(&inode->i_lock);
spin_lock(&dentry->d_lock);
if (unlikely(dentry->d_lockref.count))
goto out;
/* changed inode means that somebody had grabbed it */
if (unlikely(inode != dentry->d_inode))
goto out;
}
parent = dentry->d_parent;
if (IS_ROOT(dentry) || likely(spin_trylock(&parent->d_lock)))
return true;
spin_unlock(&dentry->d_lock);
spin_lock(&parent->d_lock);
if (unlikely(parent != dentry->d_parent)) {
spin_unlock(&parent->d_lock);
spin_lock(&dentry->d_lock);
goto out;
}
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
if (likely(!dentry->d_lockref.count))
return true;
spin_unlock(&parent->d_lock);
out:
if (inode)
spin_unlock(&inode->i_lock);
return false;
}
void shrink_dentry_list(struct list_head *list)
{
while (!list_empty(list)) {
struct dentry *dentry, *parent;
dentry = list_entry(list->prev, struct dentry, d_lru);
spin_lock(&dentry->d_lock);
rcu_read_lock();
if (!shrink_lock_dentry(dentry)) {
bool can_free = false;
rcu_read_unlock();
d_shrink_del(dentry);
if (dentry->d_lockref.count < 0)
can_free = dentry->d_flags & DCACHE_MAY_FREE;
spin_unlock(&dentry->d_lock);
if (can_free)
dentry_free(dentry);
continue;
}
rcu_read_unlock();
d_shrink_del(dentry);
parent = dentry->d_parent;
if (parent != dentry)
__dput_to_list(parent, list);
__dentry_kill(dentry);
}
}
static enum lru_status dentry_lru_isolate(struct list_head *item,
struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
{
struct list_head *freeable = arg;
struct dentry *dentry = container_of(item, struct dentry, d_lru);
/*
* we are inverting the lru lock/dentry->d_lock here,
* so use a trylock. If we fail to get the lock, just skip
* it
*/
if (!spin_trylock(&dentry->d_lock))
return LRU_SKIP;
/*
* Referenced dentries are still in use. If they have active
* counts, just remove them from the LRU. Otherwise give them
* another pass through the LRU.
*/
if (dentry->d_lockref.count) {
d_lru_isolate(lru, dentry);
spin_unlock(&dentry->d_lock);
return LRU_REMOVED;
}
if (dentry->d_flags & DCACHE_REFERENCED) {
dentry->d_flags &= ~DCACHE_REFERENCED;
spin_unlock(&dentry->d_lock);
/*
* The list move itself will be made by the common LRU code. At
* this point, we've dropped the dentry->d_lock but keep the
* lru lock. This is safe to do, since every list movement is
* protected by the lru lock even if both locks are held.
*
* This is guaranteed by the fact that all LRU management
* functions are intermediated by the LRU API calls like
* list_lru_add and list_lru_del. List movement in this file
* only ever occur through this functions or through callbacks
* like this one, that are called from the LRU API.
*
* The only exceptions to this are functions like
* shrink_dentry_list, and code that first checks for the
* DCACHE_SHRINK_LIST flag. Those are guaranteed to be
* operating only with stack provided lists after they are
* properly isolated from the main list. It is thus, always a
* local access.
*/
return LRU_ROTATE;
}
d_lru_shrink_move(lru, dentry, freeable);
spin_unlock(&dentry->d_lock);
return LRU_REMOVED;
}
/**
* prune_dcache_sb - shrink the dcache
* @sb: superblock
* @sc: shrink control, passed to list_lru_shrink_walk()
*
* Attempt to shrink the superblock dcache LRU by @sc->nr_to_scan entries. This
* is done when we need more memory and called from the superblock shrinker
* function.
*
* This function may fail to free any resources if all the dentries are in
* use.
*/
long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc)
{
LIST_HEAD(dispose);
long freed;
freed = list_lru_shrink_walk(&sb->s_dentry_lru, sc,
dentry_lru_isolate, &dispose);
shrink_dentry_list(&dispose);
return freed;
}
static enum lru_status dentry_lru_isolate_shrink(struct list_head *item,
struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
{
struct list_head *freeable = arg;
struct dentry *dentry = container_of(item, struct dentry, d_lru);
/*
* we are inverting the lru lock/dentry->d_lock here,
* so use a trylock. If we fail to get the lock, just skip
* it
*/
if (!spin_trylock(&dentry->d_lock))
return LRU_SKIP;
d_lru_shrink_move(lru, dentry, freeable);
spin_unlock(&dentry->d_lock);
return LRU_REMOVED;
}
/**
* shrink_dcache_sb - shrink dcache for a superblock
* @sb: superblock
*
* Shrink the dcache for the specified super block. This is used to free
* the dcache before unmounting a file system.
*/
void shrink_dcache_sb(struct super_block *sb)
{
do {
LIST_HEAD(dispose);
list_lru_walk(&sb->s_dentry_lru,
dentry_lru_isolate_shrink, &dispose, 1024);
shrink_dentry_list(&dispose);
} while (list_lru_count(&sb->s_dentry_lru) > 0);
}
EXPORT_SYMBOL(shrink_dcache_sb);
/**
* enum d_walk_ret - action to talke during tree walk
* @D_WALK_CONTINUE: contrinue walk
* @D_WALK_QUIT: quit walk
* @D_WALK_NORETRY: quit when retry is needed
* @D_WALK_SKIP: skip this dentry and its children
*/
enum d_walk_ret {
D_WALK_CONTINUE,
D_WALK_QUIT,
D_WALK_NORETRY,
D_WALK_SKIP,
};
/**
* d_walk - walk the dentry tree
* @parent: start of walk
* @data: data passed to @enter() and @finish()
* @enter: callback when first entering the dentry
*
* The @enter() callbacks are called with d_lock held.
*/
static void d_walk(struct dentry *parent, void *data,
enum d_walk_ret (*enter)(void *, struct dentry *))
{
struct dentry *this_parent;
struct list_head *next;
unsigned seq = 0;
enum d_walk_ret ret;
bool retry = true;
again:
read_seqbegin_or_lock(&rename_lock, &seq);
this_parent = parent;
spin_lock(&this_parent->d_lock);
ret = enter(data, this_parent);
switch (ret) {
case D_WALK_CONTINUE:
break;
case D_WALK_QUIT:
case D_WALK_SKIP:
goto out_unlock;
case D_WALK_NORETRY:
retry = false;
break;
}
repeat:
next = this_parent->d_subdirs.next;
resume:
while (next != &this_parent->d_subdirs) {
struct list_head *tmp = next;
struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
next = tmp->next;
if (unlikely(dentry->d_flags & DCACHE_DENTRY_CURSOR))
continue;
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
ret = enter(data, dentry);
switch (ret) {
case D_WALK_CONTINUE:
break;
case D_WALK_QUIT:
spin_unlock(&dentry->d_lock);
goto out_unlock;
case D_WALK_NORETRY:
retry = false;
break;
case D_WALK_SKIP:
spin_unlock(&dentry->d_lock);
continue;
}
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&this_parent->d_lock);
spin_release(&dentry->d_lock.dep_map, _RET_IP_);
this_parent = dentry;
spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
goto repeat;
}
spin_unlock(&dentry->d_lock);
}
/*
* All done at this level ... ascend and resume the search.
*/
rcu_read_lock();
ascend:
if (this_parent != parent) {
struct dentry *child = this_parent;
this_parent = child->d_parent;
spin_unlock(&child->d_lock);
spin_lock(&this_parent->d_lock);
/* might go back up the wrong parent if we have had a rename. */
if (need_seqretry(&rename_lock, seq))
goto rename_retry;
/* go into the first sibling still alive */
do {
next = child->d_child.next;
if (next == &this_parent->d_subdirs)
goto ascend;
child = list_entry(next, struct dentry, d_child);
} while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
rcu_read_unlock();
goto resume;
}
if (need_seqretry(&rename_lock, seq))
goto rename_retry;
rcu_read_unlock();
out_unlock:
spin_unlock(&this_parent->d_lock);
done_seqretry(&rename_lock, seq);
return;
rename_retry:
spin_unlock(&this_parent->d_lock);
rcu_read_unlock();
BUG_ON(seq & 1);
if (!retry)
return;
seq = 1;
goto again;
}
struct check_mount {
struct vfsmount *mnt;
unsigned int mounted;
};
static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry)
{
struct check_mount *info = data;
struct path path = { .mnt = info->mnt, .dentry = dentry };
if (likely(!d_mountpoint(dentry)))
return D_WALK_CONTINUE;
if (__path_is_mountpoint(&path)) {
info->mounted = 1;
return D_WALK_QUIT;
}
return D_WALK_CONTINUE;
}
/**
* path_has_submounts - check for mounts over a dentry in the
* current namespace.
* @parent: path to check.
*
* Return true if the parent or its subdirectories contain
* a mount point in the current namespace.
*/
int path_has_submounts(const struct path *parent)
{
struct check_mount data = { .mnt = parent->mnt, .mounted = 0 };
read_seqlock_excl(&mount_lock);
d_walk(parent->dentry, &data, path_check_mount);
read_sequnlock_excl(&mount_lock);
return data.mounted;
}
EXPORT_SYMBOL(path_has_submounts);
/*
* Called by mount code to set a mountpoint and check if the mountpoint is
* reachable (e.g. NFS can unhash a directory dentry and then the complete
* subtree can become unreachable).
*
* Only one of d_invalidate() and d_set_mounted() must succeed. For
* this reason take rename_lock and d_lock on dentry and ancestors.
*/
int d_set_mounted(struct dentry *dentry)
{
struct dentry *p;
int ret = -ENOENT;
write_seqlock(&rename_lock);
for (p = dentry->d_parent; !IS_ROOT(p); p = p->d_parent) {
/* Need exclusion wrt. d_invalidate() */
spin_lock(&p->d_lock);
if (unlikely(d_unhashed(p))) {
spin_unlock(&p->d_lock);
goto out;
}
spin_unlock(&p->d_lock);
}
spin_lock(&dentry->d_lock);
if (!d_unlinked(dentry)) {
ret = -EBUSY;
if (!d_mountpoint(dentry)) {
dentry->d_flags |= DCACHE_MOUNTED;
ret = 0;
}
}
spin_unlock(&dentry->d_lock);
out:
write_sequnlock(&rename_lock);
return ret;
}
/*
* Search the dentry child list of the specified parent,
* and move any unused dentries to the end of the unused
* list for prune_dcache(). We descend to the next level
* whenever the d_subdirs list is non-empty and continue
* searching.
*
* It returns zero iff there are no unused children,
* otherwise it returns the number of children moved to
* the end of the unused list. This may not be the total
* number of unused children, because select_parent can
* drop the lock and return early due to latency
* constraints.
*/
struct select_data {
struct dentry *start;
union {
long found;
struct dentry *victim;
};
struct list_head dispose;
};
static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
{
struct select_data *data = _data;
enum d_walk_ret ret = D_WALK_CONTINUE;
if (data->start == dentry)
goto out;
if (dentry->d_flags & DCACHE_SHRINK_LIST) {
data->found++;
} else {
if (dentry->d_flags & DCACHE_LRU_LIST)
d_lru_del(dentry);
if (!dentry->d_lockref.count) {
d_shrink_add(dentry, &data->dispose);
data->found++;
}
}
/*
* We can return to the caller if we have found some (this
* ensures forward progress). We'll be coming back to find
* the rest.
*/
if (!list_empty(&data->dispose))
ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
out:
return ret;
}
static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry)
{
struct select_data *data = _data;
enum d_walk_ret ret = D_WALK_CONTINUE;
if (data->start == dentry)
goto out;
if (dentry->d_flags & DCACHE_SHRINK_LIST) {
if (!dentry->d_lockref.count) {
rcu_read_lock();
data->victim = dentry;
return D_WALK_QUIT;
}
} else {
if (dentry->d_flags & DCACHE_LRU_LIST)
d_lru_del(dentry);
if (!dentry->d_lockref.count)
d_shrink_add(dentry, &data->dispose);
}
/*
* We can return to the caller if we have found some (this
* ensures forward progress). We'll be coming back to find
* the rest.
*/
if (!list_empty(&data->dispose))
ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
out:
return ret;
}
/**
* shrink_dcache_parent - prune dcache
* @parent: parent of entries to prune
*
* Prune the dcache to remove unused children of the parent dentry.
*/
void shrink_dcache_parent(struct dentry *parent)
{
for (;;) {
struct select_data data = {.start = parent};
INIT_LIST_HEAD(&data.dispose);
d_walk(parent, &data, select_collect);
if (!list_empty(&data.dispose)) {
shrink_dentry_list(&data.dispose);
continue;
}
cond_resched();
if (!data.found)
break;
data.victim = NULL;
d_walk(parent, &data, select_collect2);
if (data.victim) {
struct dentry *parent;
spin_lock(&data.victim->d_lock);
if (!shrink_lock_dentry(data.victim)) {
spin_unlock(&data.victim->d_lock);
rcu_read_unlock();
} else {
rcu_read_unlock();
parent = data.victim->d_parent;
if (parent != data.victim)
__dput_to_list(parent, &data.dispose);
__dentry_kill(data.victim);
}
}
if (!list_empty(&data.dispose))
shrink_dentry_list(&data.dispose);
}
}
EXPORT_SYMBOL(shrink_dcache_parent);
static enum d_walk_ret umount_check(void *_data, struct dentry *dentry)
{
/* it has busy descendents; complain about those instead */
if (!list_empty(&dentry->d_subdirs))
return D_WALK_CONTINUE;
/* root with refcount 1 is fine */
if (dentry == _data && dentry->d_lockref.count == 1)
return D_WALK_CONTINUE;
WARN(1, "BUG: Dentry %p{i=%lx,n=%pd} "
" still in use (%d) [unmount of %s %s]\n",
dentry,
dentry->d_inode ?
dentry->d_inode->i_ino : 0UL,
dentry,
dentry->d_lockref.count,
dentry->d_sb->s_type->name,
dentry->d_sb->s_id);
return D_WALK_CONTINUE;
}
static void do_one_tree(struct dentry *dentry)
{
shrink_dcache_parent(dentry);
d_walk(dentry, dentry, umount_check);
d_drop(dentry);
dput(dentry);
}
/*
* destroy the dentries attached to a superblock on unmounting
*/
void shrink_dcache_for_umount(struct super_block *sb)
{
struct dentry *dentry;
WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked");
dentry = sb->s_root;
sb->s_root = NULL;
do_one_tree(dentry);
while (!hlist_bl_empty(&sb->s_roots)) {
dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_roots), struct dentry, d_hash));
do_one_tree(dentry);
}
}
static enum d_walk_ret find_submount(void *_data, struct dentry *dentry)
{
struct dentry **victim = _data;
if (d_mountpoint(dentry)) {
__dget_dlock(dentry);
*victim = dentry;
return D_WALK_QUIT;
}
return D_WALK_CONTINUE;
}
/**
* d_invalidate - detach submounts, prune dcache, and drop
* @dentry: dentry to invalidate (aka detach, prune and drop)
*/
void d_invalidate(struct dentry *dentry)
{
bool had_submounts = false;
spin_lock(&dentry->d_lock);
if (d_unhashed(dentry)) {
spin_unlock(&dentry->d_lock);
return;
}
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
/* Negative dentries can be dropped without further checks */
if (!dentry->d_inode)
return;
shrink_dcache_parent(dentry);
for (;;) {
struct dentry *victim = NULL;
d_walk(dentry, &victim, find_submount);
if (!victim) {
if (had_submounts)
shrink_dcache_parent(dentry);
return;
}
had_submounts = true;
detach_mounts(victim);
dput(victim);
}
}
EXPORT_SYMBOL(d_invalidate);
/**
* __d_alloc - allocate a dcache entry
* @sb: filesystem it will belong to
* @name: qstr of the name
*
* Allocates a dentry. It returns %NULL if there is insufficient memory
* available. On a success the dentry is returned. The name passed in is
* copied and the copy passed in may be reused after this call.
*/
static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
{
struct dentry *dentry;
char *dname;
int err;
dentry = kmem_cache_alloc_lru(dentry_cache, &sb->s_dentry_lru,
GFP_KERNEL);
if (!dentry)
return NULL;
/*
* We guarantee that the inline name is always NUL-terminated.
* This way the memcpy() done by the name switching in rename
* will still always have a NUL at the end, even if we might
* be overwriting an internal NUL character
*/
dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
if (unlikely(!name)) {
name = &slash_name;
dname = dentry->d_iname;
} else if (name->len > DNAME_INLINE_LEN-1) {
size_t size = offsetof(struct external_name, name[1]);
struct external_name *p = kmalloc(size + name->len,
GFP_KERNEL_ACCOUNT |
__GFP_RECLAIMABLE);
if (!p) {
kmem_cache_free(dentry_cache, dentry);
return NULL;
}
atomic_set(&p->u.count, 1);
dname = p->name;
} else {
dname = dentry->d_iname;
}
dentry->d_name.len = name->len;
dentry->d_name.hash = name->hash;
memcpy(dname, name->name, name->len);
dname[name->len] = 0;
/* Make sure we always see the terminating NUL character */
smp_store_release(&dentry->d_name.name, dname); /* ^^^ */
dentry->d_lockref.count = 1;
dentry->d_flags = 0;
spin_lock_init(&dentry->d_lock);
seqcount_spinlock_init(&dentry->d_seq, &dentry->d_lock);
dentry->d_inode = NULL;
dentry->d_parent = dentry;
dentry->d_sb = sb;
dentry->d_op = NULL;
dentry->d_fsdata = NULL;
INIT_HLIST_BL_NODE(&dentry->d_hash);
INIT_LIST_HEAD(&dentry->d_lru);
INIT_LIST_HEAD(&dentry->d_subdirs);
INIT_HLIST_NODE(&dentry->d_u.d_alias);
INIT_LIST_HEAD(&dentry->d_child);
d_set_d_op(dentry, dentry->d_sb->s_d_op);
if (dentry->d_op && dentry->d_op->d_init) {
err = dentry->d_op->d_init(dentry);
if (err) {
if (dname_external(dentry))
kfree(external_name(dentry));
kmem_cache_free(dentry_cache, dentry);
return NULL;
}
}
this_cpu_inc(nr_dentry);
return dentry;
}
/**
* d_alloc - allocate a dcache entry
* @parent: parent of entry to allocate
* @name: qstr of the name
*
* Allocates a dentry. It returns %NULL if there is insufficient memory
* available. On a success the dentry is returned. The name passed in is
* copied and the copy passed in may be reused after this call.
*/
struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
{
struct dentry *dentry = __d_alloc(parent->d_sb, name);
if (!dentry)
return NULL;
spin_lock(&parent->d_lock);
/*
* don't need child lock because it is not subject
* to concurrency here
*/
__dget_dlock(parent);
dentry->d_parent = parent;
list_add(&dentry->d_child, &parent->d_subdirs);
spin_unlock(&parent->d_lock);
return dentry;
}
EXPORT_SYMBOL(d_alloc);
struct dentry *d_alloc_anon(struct super_block *sb)
{
return __d_alloc(sb, NULL);
}
EXPORT_SYMBOL(d_alloc_anon);
struct dentry *d_alloc_cursor(struct dentry * parent)
{
struct dentry *dentry = d_alloc_anon(parent->d_sb);
if (dentry) {
dentry->d_flags |= DCACHE_DENTRY_CURSOR;
dentry->d_parent = dget(parent);
}
return dentry;
}
/**
* d_alloc_pseudo - allocate a dentry (for lookup-less filesystems)
* @sb: the superblock
* @name: qstr of the name
*
* For a filesystem that just pins its dentries in memory and never
* performs lookups at all, return an unhashed IS_ROOT dentry.
* This is used for pipes, sockets et.al. - the stuff that should
* never be anyone's children or parents. Unlike all other
* dentries, these will not have RCU delay between dropping the
* last reference and freeing them.
*
* The only user is alloc_file_pseudo() and that's what should
* be considered a public interface. Don't use directly.
*/
struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name)
{
struct dentry *dentry = __d_alloc(sb, name);
if (likely(dentry))
dentry->d_flags |= DCACHE_NORCU;
return dentry;
}
struct dentry *d_alloc_name(struct dentry *parent, const char *name)
{
struct qstr q;
q.name = name;
q.hash_len = hashlen_string(parent, name);
return d_alloc(parent, &q);
}
EXPORT_SYMBOL(d_alloc_name);
void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
{
WARN_ON_ONCE(dentry->d_op);
WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH |
DCACHE_OP_COMPARE |
DCACHE_OP_REVALIDATE |
DCACHE_OP_WEAK_REVALIDATE |
DCACHE_OP_DELETE |
DCACHE_OP_REAL));
dentry->d_op = op;
if (!op)
return;
if (op->d_hash)
dentry->d_flags |= DCACHE_OP_HASH;
if (op->d_compare)
dentry->d_flags |= DCACHE_OP_COMPARE;
if (op->d_revalidate)
dentry->d_flags |= DCACHE_OP_REVALIDATE;
if (op->d_weak_revalidate)
dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE;
if (op->d_delete)
dentry->d_flags |= DCACHE_OP_DELETE;
if (op->d_prune)
dentry->d_flags |= DCACHE_OP_PRUNE;
if (op->d_real)
dentry->d_flags |= DCACHE_OP_REAL;
}
EXPORT_SYMBOL(d_set_d_op);
/*
* d_set_fallthru - Mark a dentry as falling through to a lower layer
* @dentry - The dentry to mark
*
* Mark a dentry as falling through to the lower layer (as set with
* d_pin_lower()). This flag may be recorded on the medium.
*/
void d_set_fallthru(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_FALLTHRU;
spin_unlock(&dentry->d_lock);
}
EXPORT_SYMBOL(d_set_fallthru);
static unsigned d_flags_for_inode(struct inode *inode)
{
unsigned add_flags = DCACHE_REGULAR_TYPE;
if (!inode)
return DCACHE_MISS_TYPE;
if (S_ISDIR(inode->i_mode)) {
add_flags = DCACHE_DIRECTORY_TYPE;
if (unlikely(!(inode->i_opflags & IOP_LOOKUP))) {
if (unlikely(!inode->i_op->lookup))
add_flags = DCACHE_AUTODIR_TYPE;
else
inode->i_opflags |= IOP_LOOKUP;
}
goto type_determined;
}
if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
if (unlikely(inode->i_op->get_link)) {
add_flags = DCACHE_SYMLINK_TYPE;
goto type_determined;
}
inode->i_opflags |= IOP_NOFOLLOW;
}
if (unlikely(!S_ISREG(inode->i_mode)))
add_flags = DCACHE_SPECIAL_TYPE;
type_determined:
if (unlikely(IS_AUTOMOUNT(inode)))
add_flags |= DCACHE_NEED_AUTOMOUNT;
return add_flags;
}
static void __d_instantiate(struct dentry *dentry, struct inode *inode)
{
unsigned add_flags = d_flags_for_inode(inode);
WARN_ON(d_in_lookup(dentry));
spin_lock(&dentry->d_lock);
/*
* Decrement negative dentry count if it was in the LRU list.
*/
if (dentry->d_flags & DCACHE_LRU_LIST)
this_cpu_dec(nr_dentry_negative);
hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
raw_write_seqcount_begin(&dentry->d_seq);
__d_set_inode_and_type(dentry, inode, add_flags);
raw_write_seqcount_end(&dentry->d_seq);
fsnotify_update_flags(dentry);
spin_unlock(&dentry->d_lock);
}
/**
* d_instantiate - fill in inode information for a dentry
* @entry: dentry to complete
* @inode: inode to attach to this dentry
*
* Fill in inode information in the entry.
*
* This turns negative dentries into productive full members
* of society.
*
* NOTE! This assumes that the inode count has been incremented
* (or otherwise set) by the caller to indicate that it is now
* in use by the dcache.
*/
void d_instantiate(struct dentry *entry, struct inode * inode)
{
BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
if (inode) {
security_d_instantiate(entry, inode);
spin_lock(&inode->i_lock);
__d_instantiate(entry, inode);
spin_unlock(&inode->i_lock);
}
}
EXPORT_SYMBOL(d_instantiate);
/*
* This should be equivalent to d_instantiate() + unlock_new_inode(),
* with lockdep-related part of unlock_new_inode() done before
* anything else. Use that instead of open-coding d_instantiate()/
* unlock_new_inode() combinations.
*/
void d_instantiate_new(struct dentry *entry, struct inode *inode)
{
BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
BUG_ON(!inode);
lockdep_annotate_inode_mutex_key(inode);
security_d_instantiate(entry, inode);
spin_lock(&inode->i_lock);
__d_instantiate(entry, inode);
WARN_ON(!(inode->i_state & I_NEW));
inode->i_state &= ~I_NEW & ~I_CREATING;
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(d_instantiate_new);
struct dentry *d_make_root(struct inode *root_inode)
{
struct dentry *res = NULL;
if (root_inode) {
res = d_alloc_anon(root_inode->i_sb);
if (res)
d_instantiate(res, root_inode);
else
iput(root_inode);
}
return res;
}
EXPORT_SYMBOL(d_make_root);
static struct dentry *__d_instantiate_anon(struct dentry *dentry,
struct inode *inode,
bool disconnected)
{
struct dentry *res;
unsigned add_flags;
security_d_instantiate(dentry, inode);
spin_lock(&inode->i_lock);
res = __d_find_any_alias(inode);
if (res) {
spin_unlock(&inode->i_lock);
dput(dentry);
goto out_iput;
}
/* attach a disconnected dentry */
add_flags = d_flags_for_inode(inode);
if (disconnected)
add_flags |= DCACHE_DISCONNECTED;
spin_lock(&dentry->d_lock);
__d_set_inode_and_type(dentry, inode, add_flags);
hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
if (!disconnected) {
hlist_bl_lock(&dentry->d_sb->s_roots);
hlist_bl_add_head(&dentry->d_hash, &dentry->d_sb->s_roots);
hlist_bl_unlock(&dentry->d_sb->s_roots);
}
spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
return dentry;
out_iput:
iput(inode);
return res;
}
struct dentry *d_instantiate_anon(struct dentry *dentry, struct inode *inode)
{
return __d_instantiate_anon(dentry, inode, true);
}
EXPORT_SYMBOL(d_instantiate_anon);
static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
{
struct dentry *tmp;
struct dentry *res;
if (!inode)
return ERR_PTR(-ESTALE);
if (IS_ERR(inode))
return ERR_CAST(inode);
res = d_find_any_alias(inode);
if (res)
goto out_iput;
tmp = d_alloc_anon(inode->i_sb);
if (!tmp) {
res = ERR_PTR(-ENOMEM);
goto out_iput;
}
return __d_instantiate_anon(tmp, inode, disconnected);
out_iput:
iput(inode);
return res;
}
/**
* d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode
* @inode: inode to allocate the dentry for
*
* Obtain a dentry for an inode resulting from NFS filehandle conversion or
* similar open by handle operations. The returned dentry may be anonymous,
* or may have a full name (if the inode was already in the cache).
*
* When called on a directory inode, we must ensure that the inode only ever
* has one dentry. If a dentry is found, that is returned instead of
* allocating a new one.
*
* On successful return, the reference to the inode has been transferred
* to the dentry. In case of an error the reference on the inode is released.
* To make it easier to use in export operations a %NULL or IS_ERR inode may
* be passed in and the error will be propagated to the return value,
* with a %NULL @inode replaced by ERR_PTR(-ESTALE).
*/
struct dentry *d_obtain_alias(struct inode *inode)
{
return __d_obtain_alias(inode, true);
}
EXPORT_SYMBOL(d_obtain_alias);
/**
* d_obtain_root - find or allocate a dentry for a given inode
* @inode: inode to allocate the dentry for
*
* Obtain an IS_ROOT dentry for the root of a filesystem.
*
* We must ensure that directory inodes only ever have one dentry. If a
* dentry is found, that is returned instead of allocating a new one.
*
* On successful return, the reference to the inode has been transferred
* to the dentry. In case of an error the reference on the inode is
* released. A %NULL or IS_ERR inode may be passed in and will be the
* error will be propagate to the return value, with a %NULL @inode
* replaced by ERR_PTR(-ESTALE).
*/
struct dentry *d_obtain_root(struct inode *inode)
{
return __d_obtain_alias(inode, false);
}
EXPORT_SYMBOL(d_obtain_root);
/**
* d_add_ci - lookup or allocate new dentry with case-exact name
* @inode: the inode case-insensitive lookup has found
* @dentry: the negative dentry that was passed to the parent's lookup func
* @name: the case-exact name to be associated with the returned dentry
*
* This is to avoid filling the dcache with case-insensitive names to the
* same inode, only the actual correct case is stored in the dcache for
* case-insensitive filesystems.
*
* For a case-insensitive lookup match and if the case-exact dentry
* already exists in the dcache, use it and return it.
*
* If no entry exists with the exact case name, allocate new dentry with
* the exact case, and return the spliced entry.
*/
struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
struct qstr *name)
{
struct dentry *found, *res;
/*
* First check if a dentry matching the name already exists,
* if not go ahead and create it now.
*/
found = d_hash_and_lookup(dentry->d_parent, name);
if (found) {
iput(inode);
return found;
}
if (d_in_lookup(dentry)) {
found = d_alloc_parallel(dentry->d_parent, name,
dentry->d_wait);
if (IS_ERR(found) || !d_in_lookup(found)) {
iput(inode);
return found;
}
} else {
found = d_alloc(dentry->d_parent, name);
if (!found) {
iput(inode);
return ERR_PTR(-ENOMEM);
}
}
res = d_splice_alias(inode, found);
if (res) {
d_lookup_done(found);
dput(found);
return res;
}
return found;
}
EXPORT_SYMBOL(d_add_ci);
/**
* d_same_name - compare dentry name with case-exact name
* @parent: parent dentry
* @dentry: the negative dentry that was passed to the parent's lookup func
* @name: the case-exact name to be associated with the returned dentry
*
* Return: true if names are same, or false
*/
bool d_same_name(const struct dentry *dentry, const struct dentry *parent,
const struct qstr *name)
{
if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) {
if (dentry->d_name.len != name->len)
return false;
return dentry_cmp(dentry, name->name, name->len) == 0;
}
return parent->d_op->d_compare(dentry,
dentry->d_name.len, dentry->d_name.name,
name) == 0;
}
EXPORT_SYMBOL_GPL(d_same_name);
/*
* This is __d_lookup_rcu() when the parent dentry has
* DCACHE_OP_COMPARE, which makes things much nastier.
*/
static noinline struct dentry *__d_lookup_rcu_op_compare(
const struct dentry *parent,
const struct qstr *name,
unsigned *seqp)
{
u64 hashlen = name->hash_len;
struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen));
struct hlist_bl_node *node;
struct dentry *dentry;
hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
int tlen;
const char *tname;
unsigned seq;
seqretry:
seq = raw_seqcount_begin(&dentry->d_seq);
if (dentry->d_parent != parent)
continue;
if (d_unhashed(dentry))
continue;
if (dentry->d_name.hash != hashlen_hash(hashlen))
continue;
tlen = dentry->d_name.len;
tname = dentry->d_name.name;
/* we want a consistent (name,len) pair */
if (read_seqcount_retry(&dentry->d_seq, seq)) {
cpu_relax();
goto seqretry;
}
if (parent->d_op->d_compare(dentry, tlen, tname, name) != 0)
continue;
*seqp = seq;
return dentry;
}
return NULL;
}
/**
* __d_lookup_rcu - search for a dentry (racy, store-free)
* @parent: parent dentry
* @name: qstr of name we wish to find
* @seqp: returns d_seq value at the point where the dentry was found
* Returns: dentry, or NULL
*
* __d_lookup_rcu is the dcache lookup function for rcu-walk name
* resolution (store-free path walking) design described in
* Documentation/filesystems/path-lookup.txt.
*
* This is not to be used outside core vfs.
*
* __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock
* held, and rcu_read_lock held. The returned dentry must not be stored into
* without taking d_lock and checking d_seq sequence count against @seq
* returned here.
*
* A refcount may be taken on the found dentry with the d_rcu_to_refcount
* function.
*
* Alternatively, __d_lookup_rcu may be called again to look up the child of
* the returned dentry, so long as its parent's seqlock is checked after the
* child is looked up. Thus, an interlocking stepping of sequence lock checks
* is formed, giving integrity down the path walk.
*
* NOTE! The caller *has* to check the resulting dentry against the sequence
* number we've returned before using any of the resulting dentry state!
*/
struct dentry *__d_lookup_rcu(const struct dentry *parent,
const struct qstr *name,
unsigned *seqp)
{
u64 hashlen = name->hash_len;
const unsigned char *str = name->name;
struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen));
struct hlist_bl_node *node;
struct dentry *dentry;
/*
* Note: There is significant duplication with __d_lookup_rcu which is
* required to prevent single threaded performance regressions
* especially on architectures where smp_rmb (in seqcounts) are costly.
* Keep the two functions in sync.
*/
if (unlikely(parent->d_flags & DCACHE_OP_COMPARE))
return __d_lookup_rcu_op_compare(parent, name, seqp);
/*
* The hash list is protected using RCU.
*
* Carefully use d_seq when comparing a candidate dentry, to avoid
* races with d_move().
*
* It is possible that concurrent renames can mess up our list
* walk here and result in missing our dentry, resulting in the
* false-negative result. d_lookup() protects against concurrent
* renames using rename_lock seqlock.
*
* See Documentation/filesystems/path-lookup.txt for more details.
*/
hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
unsigned seq;
/*
* The dentry sequence count protects us from concurrent
* renames, and thus protects parent and name fields.
*
* The caller must perform a seqcount check in order
* to do anything useful with the returned dentry.
*
* NOTE! We do a "raw" seqcount_begin here. That means that
* we don't wait for the sequence count to stabilize if it
* is in the middle of a sequence change. If we do the slow
* dentry compare, we will do seqretries until it is stable,
* and if we end up with a successful lookup, we actually
* want to exit RCU lookup anyway.
*
* Note that raw_seqcount_begin still *does* smp_rmb(), so
* we are still guaranteed NUL-termination of ->d_name.name.
*/
seq = raw_seqcount_begin(&dentry->d_seq);
if (dentry->d_parent != parent)
continue;
if (d_unhashed(dentry))
continue;
if (dentry->d_name.hash_len != hashlen)
continue;
if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0)
continue;
*seqp = seq;
return dentry;
}
return NULL;
}
/**
* d_lookup - search for a dentry
* @parent: parent dentry
* @name: qstr of name we wish to find
* Returns: dentry, or NULL
*
* d_lookup searches the children of the parent dentry for the name in
* question. If the dentry is found its reference count is incremented and the
* dentry is returned. The caller must use dput to free the entry when it has
* finished using it. %NULL is returned if the dentry does not exist.
*/
struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name)
{
struct dentry *dentry;
unsigned seq;
do {
seq = read_seqbegin(&rename_lock);
dentry = __d_lookup(parent, name);
if (dentry)
break;
} while (read_seqretry(&rename_lock, seq));
return dentry;
}
EXPORT_SYMBOL(d_lookup);
/**
* __d_lookup - search for a dentry (racy)
* @parent: parent dentry
* @name: qstr of name we wish to find
* Returns: dentry, or NULL
*
* __d_lookup is like d_lookup, however it may (rarely) return a
* false-negative result due to unrelated rename activity.
*
* __d_lookup is slightly faster by avoiding rename_lock read seqlock,
* however it must be used carefully, eg. with a following d_lookup in
* the case of failure.
*
* __d_lookup callers must be commented.
*/
struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name)
{
unsigned int hash = name->hash;
struct hlist_bl_head *b = d_hash(hash);
struct hlist_bl_node *node;
struct dentry *found = NULL;
struct dentry *dentry;
/*
* Note: There is significant duplication with __d_lookup_rcu which is
* required to prevent single threaded performance regressions
* especially on architectures where smp_rmb (in seqcounts) are costly.
* Keep the two functions in sync.
*/
/*
* The hash list is protected using RCU.
*
* Take d_lock when comparing a candidate dentry, to avoid races
* with d_move().
*
* It is possible that concurrent renames can mess up our list
* walk here and result in missing our dentry, resulting in the
* false-negative result. d_lookup() protects against concurrent
* renames using rename_lock seqlock.
*
* See Documentation/filesystems/path-lookup.txt for more details.
*/
rcu_read_lock();
hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
if (dentry->d_name.hash != hash)
continue;
spin_lock(&dentry->d_lock);
if (dentry->d_parent != parent)
goto next;
if (d_unhashed(dentry))
goto next;
if (!d_same_name(dentry, parent, name))
goto next;
dentry->d_lockref.count++;
found = dentry;
spin_unlock(&dentry->d_lock);
break;
next:
spin_unlock(&dentry->d_lock);
}
rcu_read_unlock();
return found;
}
/**
* d_hash_and_lookup - hash the qstr then search for a dentry
* @dir: Directory to search in
* @name: qstr of name we wish to find
*
* On lookup failure NULL is returned; on bad name - ERR_PTR(-error)
*/
struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
{
/*
* Check for a fs-specific hash function. Note that we must
* calculate the standard hash first, as the d_op->d_hash()
* routine may choose to leave the hash value unchanged.
*/
name->hash = full_name_hash(dir, name->name, name->len);
if (dir->d_flags & DCACHE_OP_HASH) {
int err = dir->d_op->d_hash(dir, name);
if (unlikely(err < 0))
return ERR_PTR(err);
}
return d_lookup(dir, name);
}
EXPORT_SYMBOL(d_hash_and_lookup);
/*
* When a file is deleted, we have two options:
* - turn this dentry into a negative dentry
* - unhash this dentry and free it.
*
* Usually, we want to just turn this into
* a negative dentry, but if anybody else is
* currently using the dentry or the inode
* we can't do that and we fall back on removing
* it from the hash queues and waiting for
* it to be deleted later when it has no users
*/
/**
* d_delete - delete a dentry
* @dentry: The dentry to delete
*
* Turn the dentry into a negative dentry if possible, otherwise
* remove it from the hash queues so it can be deleted later
*/
void d_delete(struct dentry * dentry)
{
struct inode *inode = dentry->d_inode;
spin_lock(&inode->i_lock);
spin_lock(&dentry->d_lock);
/*
* Are we the only user?
*/
if (dentry->d_lockref.count == 1) {
dentry->d_flags &= ~DCACHE_CANT_MOUNT;
dentry_unlink_inode(dentry);
} else {
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
}
}
EXPORT_SYMBOL(d_delete);
static void __d_rehash(struct dentry *entry)
{
struct hlist_bl_head *b = d_hash(entry->d_name.hash);
hlist_bl_lock(b);
hlist_bl_add_head_rcu(&entry->d_hash, b);
hlist_bl_unlock(b);
}
/**
* d_rehash - add an entry back to the hash
* @entry: dentry to add to the hash
*
* Adds a dentry to the hash according to its name.
*/
void d_rehash(struct dentry * entry)
{
spin_lock(&entry->d_lock);
__d_rehash(entry);
spin_unlock(&entry->d_lock);
}
EXPORT_SYMBOL(d_rehash);
static inline unsigned start_dir_add(struct inode *dir)
{
preempt_disable_nested();
for (;;) {
unsigned n = dir->i_dir_seq;
if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
return n;
cpu_relax();
}
}
static inline void end_dir_add(struct inode *dir, unsigned int n,
wait_queue_head_t *d_wait)
{
smp_store_release(&dir->i_dir_seq, n + 2);
preempt_enable_nested();
wake_up_all(d_wait);
}
static void d_wait_lookup(struct dentry *dentry)
{
if (d_in_lookup(dentry)) {
DECLARE_WAITQUEUE(wait, current);
add_wait_queue(dentry->d_wait, &wait);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock(&dentry->d_lock);
schedule();
spin_lock(&dentry->d_lock);
} while (d_in_lookup(dentry));
}
}
struct dentry *d_alloc_parallel(struct dentry *parent,
const struct qstr *name,
wait_queue_head_t *wq)
{
unsigned int hash = name->hash;
struct hlist_bl_head *b = in_lookup_hash(parent, hash);
struct hlist_bl_node *node;
struct dentry *new = d_alloc(parent, name);
struct dentry *dentry;
unsigned seq, r_seq, d_seq;
if (unlikely(!new))
return ERR_PTR(-ENOMEM);
retry:
rcu_read_lock();
seq = smp_load_acquire(&parent->d_inode->i_dir_seq);
r_seq = read_seqbegin(&rename_lock);
dentry = __d_lookup_rcu(parent, name, &d_seq);
if (unlikely(dentry)) {
if (!lockref_get_not_dead(&dentry->d_lockref)) {
rcu_read_unlock();
goto retry;
}
if (read_seqcount_retry(&dentry->d_seq, d_seq)) {
rcu_read_unlock();
dput(dentry);
goto retry;
}
rcu_read_unlock();
dput(new);
return dentry;
}
if (unlikely(read_seqretry(&rename_lock, r_seq))) {
rcu_read_unlock();
goto retry;
}
if (unlikely(seq & 1)) {
rcu_read_unlock();
goto retry;
}
hlist_bl_lock(b);
if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
hlist_bl_unlock(b);
rcu_read_unlock();
goto retry;
}
/*
* No changes for the parent since the beginning of d_lookup().
* Since all removals from the chain happen with hlist_bl_lock(),
* any potential in-lookup matches are going to stay here until
* we unlock the chain. All fields are stable in everything
* we encounter.
*/
hlist_bl_for_each_entry(dentry, node, b, d_u.d_in_lookup_hash) {
if (dentry->d_name.hash != hash)
continue;
if (dentry->d_parent != parent)
continue;
if (!d_same_name(dentry, parent, name))
continue;
hlist_bl_unlock(b);
/* now we can try to grab a reference */
if (!lockref_get_not_dead(&dentry->d_lockref)) {
rcu_read_unlock();
goto retry;
}
rcu_read_unlock();
/*
* somebody is likely to be still doing lookup for it;
* wait for them to finish
*/
spin_lock(&dentry->d_lock);
d_wait_lookup(dentry);
/*
* it's not in-lookup anymore; in principle we should repeat
* everything from dcache lookup, but it's likely to be what
* d_lookup() would've found anyway. If it is, just return it;
* otherwise we really have to repeat the whole thing.
*/
if (unlikely(dentry->d_name.hash != hash))
goto mismatch;
if (unlikely(dentry->d_parent != parent))
goto mismatch;
if (unlikely(d_unhashed(dentry)))
goto mismatch;
if (unlikely(!d_same_name(dentry, parent, name)))
goto mismatch;
/* OK, it *is* a hashed match; return it */
spin_unlock(&dentry->d_lock);
dput(new);
return dentry;
}
rcu_read_unlock();
/* we can't take ->d_lock here; it's OK, though. */
new->d_flags |= DCACHE_PAR_LOOKUP;
new->d_wait = wq;
hlist_bl_add_head_rcu(&new->d_u.d_in_lookup_hash, b);
hlist_bl_unlock(b);
return new;
mismatch:
spin_unlock(&dentry->d_lock);
dput(dentry);
goto retry;
}
EXPORT_SYMBOL(d_alloc_parallel);
/*
* - Unhash the dentry
* - Retrieve and clear the waitqueue head in dentry
* - Return the waitqueue head
*/
static wait_queue_head_t *__d_lookup_unhash(struct dentry *dentry)
{
wait_queue_head_t *d_wait;
struct hlist_bl_head *b;
lockdep_assert_held(&dentry->d_lock);
b = in_lookup_hash(dentry->d_parent, dentry->d_name.hash);
hlist_bl_lock(b);
dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
__hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
d_wait = dentry->d_wait;
dentry->d_wait = NULL;
hlist_bl_unlock(b);
INIT_HLIST_NODE(&dentry->d_u.d_alias);
INIT_LIST_HEAD(&dentry->d_lru);
return d_wait;
}
void __d_lookup_unhash_wake(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
wake_up_all(__d_lookup_unhash(dentry));
spin_unlock(&dentry->d_lock);
}
EXPORT_SYMBOL(__d_lookup_unhash_wake);
/* inode->i_lock held if inode is non-NULL */
static inline void __d_add(struct dentry *dentry, struct inode *inode)
{
wait_queue_head_t *d_wait;
struct inode *dir = NULL;
unsigned n;
spin_lock(&dentry->d_lock);
if (unlikely(d_in_lookup(dentry))) {
dir = dentry->d_parent->d_inode;
n = start_dir_add(dir);
d_wait = __d_lookup_unhash(dentry);
}
if (inode) {
unsigned add_flags = d_flags_for_inode(inode);
hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
raw_write_seqcount_begin(&dentry->d_seq);
__d_set_inode_and_type(dentry, inode, add_flags);
raw_write_seqcount_end(&dentry->d_seq);
fsnotify_update_flags(dentry);
}
__d_rehash(dentry);
if (dir)
end_dir_add(dir, n, d_wait);
spin_unlock(&dentry->d_lock);
if (inode)
spin_unlock(&inode->i_lock);
}
/**
* d_add - add dentry to hash queues
* @entry: dentry to add
* @inode: The inode to attach to this dentry
*
* This adds the entry to the hash queues and initializes @inode.
* The entry was actually filled in earlier during d_alloc().
*/
void d_add(struct dentry *entry, struct inode *inode)
{
if (inode) {
security_d_instantiate(entry, inode);
spin_lock(&inode->i_lock);
}
__d_add(entry, inode);
}
EXPORT_SYMBOL(d_add);
/**
* d_exact_alias - find and hash an exact unhashed alias
* @entry: dentry to add
* @inode: The inode to go with this dentry
*
* If an unhashed dentry with the same name/parent and desired
* inode already exists, hash and return it. Otherwise, return
* NULL.
*
* Parent directory should be locked.
*/
struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode)
{
struct dentry *alias;
unsigned int hash = entry->d_name.hash;
spin_lock(&inode->i_lock);
hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
/*
* Don't need alias->d_lock here, because aliases with
* d_parent == entry->d_parent are not subject to name or
* parent changes, because the parent inode i_mutex is held.
*/
if (alias->d_name.hash != hash)
continue;
if (alias->d_parent != entry->d_parent)
continue;
if (!d_same_name(alias, entry->d_parent, &entry->d_name))
continue;
spin_lock(&alias->d_lock);
if (!d_unhashed(alias)) {
spin_unlock(&alias->d_lock);
alias = NULL;
} else {
__dget_dlock(alias);
__d_rehash(alias);
spin_unlock(&alias->d_lock);
}
spin_unlock(&inode->i_lock);
return alias;
}
spin_unlock(&inode->i_lock);
return NULL;
}
EXPORT_SYMBOL(d_exact_alias);
static void swap_names(struct dentry *dentry, struct dentry *target)
{
if (unlikely(dname_external(target))) {
if (unlikely(dname_external(dentry))) {
/*
* Both external: swap the pointers
*/
swap(target->d_name.name, dentry->d_name.name);
} else {
/*
* dentry:internal, target:external. Steal target's
* storage and make target internal.
*/
memcpy(target->d_iname, dentry->d_name.name,
dentry->d_name.len + 1);
dentry->d_name.name = target->d_name.name;
target->d_name.name = target->d_iname;
}
} else {
if (unlikely(dname_external(dentry))) {
/*
* dentry:external, target:internal. Give dentry's
* storage to target and make dentry internal
*/
memcpy(dentry->d_iname, target->d_name.name,
target->d_name.len + 1);
target->d_name.name = dentry->d_name.name;
dentry->d_name.name = dentry->d_iname;
} else {
/*
* Both are internal.
*/
unsigned int i;
BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
swap(((long *) &dentry->d_iname)[i],
((long *) &target->d_iname)[i]);
}
}
}
swap(dentry->d_name.hash_len, target->d_name.hash_len);
}
static void copy_name(struct dentry *dentry, struct dentry *target)
{
struct external_name *old_name = NULL;
if (unlikely(dname_external(dentry)))
old_name = external_name(dentry);
if (unlikely(dname_external(target))) {
atomic_inc(&external_name(target)->u.count);
dentry->d_name = target->d_name;
} else {
memcpy(dentry->d_iname, target->d_name.name,
target->d_name.len + 1);
dentry->d_name.name = dentry->d_iname;
dentry->d_name.hash_len = target->d_name.hash_len;
}
if (old_name && likely(atomic_dec_and_test(&old_name->u.count)))
kfree_rcu(old_name, u.head);
}
/*
* __d_move - move a dentry
* @dentry: entry to move
* @target: new dentry
* @exchange: exchange the two dentries
*
* Update the dcache to reflect the move of a file name. Negative
* dcache entries should not be moved in this way. Caller must hold
* rename_lock, the i_mutex of the source and target directories,
* and the sb->s_vfs_rename_mutex if they differ. See lock_rename().
*/
static void __d_move(struct dentry *dentry, struct dentry *target,
bool exchange)
{
struct dentry *old_parent, *p;
wait_queue_head_t *d_wait;
struct inode *dir = NULL;
unsigned n;
WARN_ON(!dentry->d_inode);
if (WARN_ON(dentry == target))
return;
BUG_ON(d_ancestor(target, dentry));
old_parent = dentry->d_parent;
p = d_ancestor(old_parent, target);
if (IS_ROOT(dentry)) {
BUG_ON(p);
spin_lock(&target->d_parent->d_lock);
} else if (!p) {
/* target is not a descendent of dentry->d_parent */
spin_lock(&target->d_parent->d_lock);
spin_lock_nested(&old_parent->d_lock, DENTRY_D_LOCK_NESTED);
} else {
BUG_ON(p == dentry);
spin_lock(&old_parent->d_lock);
if (p != target)
spin_lock_nested(&target->d_parent->d_lock,
DENTRY_D_LOCK_NESTED);
}
spin_lock_nested(&dentry->d_lock, 2);
spin_lock_nested(&target->d_lock, 3);
if (unlikely(d_in_lookup(target))) {
dir = target->d_parent->d_inode;
n = start_dir_add(dir);
d_wait = __d_lookup_unhash(target);
}
write_seqcount_begin(&dentry->d_seq);
write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
/* unhash both */
if (!d_unhashed(dentry))
___d_drop(dentry);
if (!d_unhashed(target))
___d_drop(target);
/* ... and switch them in the tree */
dentry->d_parent = target->d_parent;
if (!exchange) {
copy_name(dentry, target);
target->d_hash.pprev = NULL;
dentry->d_parent->d_lockref.count++;
if (dentry != old_parent) /* wasn't IS_ROOT */
WARN_ON(!--old_parent->d_lockref.count);
} else {
target->d_parent = old_parent;
swap_names(dentry, target);
list_move(&target->d_child, &target->d_parent->d_subdirs);
__d_rehash(target);
fsnotify_update_flags(target);
}
list_move(&dentry->d_child, &dentry->d_parent->d_subdirs);
__d_rehash(dentry);
fsnotify_update_flags(dentry);
fscrypt_handle_d_move(dentry);
write_seqcount_end(&target->d_seq);
write_seqcount_end(&dentry->d_seq);
if (dir)
end_dir_add(dir, n, d_wait);
if (dentry->d_parent != old_parent)
spin_unlock(&dentry->d_parent->d_lock);
if (dentry != old_parent)
spin_unlock(&old_parent->d_lock);
spin_unlock(&target->d_lock);
spin_unlock(&dentry->d_lock);
}
/*
* d_move - move a dentry
* @dentry: entry to move
* @target: new dentry
*
* Update the dcache to reflect the move of a file name. Negative
* dcache entries should not be moved in this way. See the locking
* requirements for __d_move.
*/
void d_move(struct dentry *dentry, struct dentry *target)
{
write_seqlock(&rename_lock);
__d_move(dentry, target, false);
write_sequnlock(&rename_lock);
}
EXPORT_SYMBOL(d_move);
/*
* d_exchange - exchange two dentries
* @dentry1: first dentry
* @dentry2: second dentry
*/
void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
{
write_seqlock(&rename_lock);
WARN_ON(!dentry1->d_inode);
WARN_ON(!dentry2->d_inode);
WARN_ON(IS_ROOT(dentry1));
WARN_ON(IS_ROOT(dentry2));
__d_move(dentry1, dentry2, true);
write_sequnlock(&rename_lock);
}
/**
* d_ancestor - search for an ancestor
* @p1: ancestor dentry
* @p2: child dentry
*
* Returns the ancestor dentry of p2 which is a child of p1, if p1 is
* an ancestor of p2, else NULL.
*/
struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
{
struct dentry *p;
for (p = p2; !IS_ROOT(p); p = p->d_parent) {
if (p->d_parent == p1)
return p;
}
return NULL;
}
/*
* This helper attempts to cope with remotely renamed directories
*
* It assumes that the caller is already holding
* dentry->d_parent->d_inode->i_mutex, and rename_lock
*
* Note: If ever the locking in lock_rename() changes, then please
* remember to update this too...
*/
static int __d_unalias(struct inode *inode,
struct dentry *dentry, struct dentry *alias)
{
struct mutex *m1 = NULL;
struct rw_semaphore *m2 = NULL;
int ret = -ESTALE;
/* If alias and dentry share a parent, then no extra locks required */
if (alias->d_parent == dentry->d_parent)
goto out_unalias;
/* See lock_rename() */
if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex))
goto out_err;
m1 = &dentry->d_sb->s_vfs_rename_mutex;
if (!inode_trylock_shared(alias->d_parent->d_inode))
goto out_err;
m2 = &alias->d_parent->d_inode->i_rwsem;
out_unalias:
__d_move(alias, dentry, false);
ret = 0;
out_err:
if (m2)
up_read(m2);
if (m1)
mutex_unlock(m1);
return ret;
}
/**
* d_splice_alias - splice a disconnected dentry into the tree if one exists
* @inode: the inode which may have a disconnected dentry
* @dentry: a negative dentry which we want to point to the inode.
*
* If inode is a directory and has an IS_ROOT alias, then d_move that in
* place of the given dentry and return it, else simply d_add the inode
* to the dentry and return NULL.
*
* If a non-IS_ROOT directory is found, the filesystem is corrupt, and
* we should error out: directories can't have multiple aliases.
*
* This is needed in the lookup routine of any filesystem that is exportable
* (via knfsd) so that we can build dcache paths to directories effectively.
*
* If a dentry was found and moved, then it is returned. Otherwise NULL
* is returned. This matches the expected return value of ->lookup.
*
* Cluster filesystems may call this function with a negative, hashed dentry.
* In that case, we know that the inode will be a regular file, and also this
* will only occur during atomic_open. So we need to check for the dentry
* being already hashed only in the final case.
*/
struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
{
if (IS_ERR(inode))
return ERR_CAST(inode);
BUG_ON(!d_unhashed(dentry));
if (!inode)
goto out;
security_d_instantiate(dentry, inode);
spin_lock(&inode->i_lock);
if (S_ISDIR(inode->i_mode)) {
struct dentry *new = __d_find_any_alias(inode);
if (unlikely(new)) {
/* The reference to new ensures it remains an alias */
spin_unlock(&inode->i_lock);
write_seqlock(&rename_lock);
if (unlikely(d_ancestor(new, dentry))) {
write_sequnlock(&rename_lock);
dput(new);
new = ERR_PTR(-ELOOP);
pr_warn_ratelimited(
"VFS: Lookup of '%s' in %s %s"
" would have caused loop\n",
dentry->d_name.name,
inode->i_sb->s_type->name,
inode->i_sb->s_id);
} else if (!IS_ROOT(new)) {
struct dentry *old_parent = dget(new->d_parent);
int err = __d_unalias(inode, dentry, new);
write_sequnlock(&rename_lock);
if (err) {
dput(new);
new = ERR_PTR(err);
}
dput(old_parent);
} else {
__d_move(new, dentry, false);
write_sequnlock(&rename_lock);
}
iput(inode);
return new;
}
}
out:
__d_add(dentry, inode);
return NULL;
}
EXPORT_SYMBOL(d_splice_alias);
/*
* Test whether new_dentry is a subdirectory of old_dentry.
*
* Trivially implemented using the dcache structure
*/
/**
* is_subdir - is new dentry a subdirectory of old_dentry
* @new_dentry: new dentry
* @old_dentry: old dentry
*
* Returns true if new_dentry is a subdirectory of the parent (at any depth).
* Returns false otherwise.
* Caller must ensure that "new_dentry" is pinned before calling is_subdir()
*/
bool is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
{
bool result;
unsigned seq;
if (new_dentry == old_dentry)
return true;
do {
/* for restarting inner loop in case of seq retry */
seq = read_seqbegin(&rename_lock);
/*
* Need rcu_readlock to protect against the d_parent trashing
* due to d_move
*/
rcu_read_lock();
if (d_ancestor(old_dentry, new_dentry))
result = true;
else
result = false;
rcu_read_unlock();
} while (read_seqretry(&rename_lock, seq));
return result;
}
EXPORT_SYMBOL(is_subdir);
static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
{
struct dentry *root = data;
if (dentry != root) {
if (d_unhashed(dentry) || !dentry->d_inode)
return D_WALK_SKIP;
if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
dentry->d_flags |= DCACHE_GENOCIDE;
dentry->d_lockref.count--;
}
}
return D_WALK_CONTINUE;
}
void d_genocide(struct dentry *parent)
{
d_walk(parent, parent, d_genocide_kill);
}
void d_tmpfile(struct file *file, struct inode *inode)
{
struct dentry *dentry = file->f_path.dentry;
inode_dec_link_count(inode);
BUG_ON(dentry->d_name.name != dentry->d_iname ||
!hlist_unhashed(&dentry->d_u.d_alias) ||
!d_unlinked(dentry));
spin_lock(&dentry->d_parent->d_lock);
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
dentry->d_name.len = sprintf(dentry->d_iname, "#%llu",
(unsigned long long)inode->i_ino);
spin_unlock(&dentry->d_lock);
spin_unlock(&dentry->d_parent->d_lock);
d_instantiate(dentry, inode);
}
EXPORT_SYMBOL(d_tmpfile);
static __initdata unsigned long dhash_entries;
static int __init set_dhash_entries(char *str)
{
if (!str)
return 0;
dhash_entries = simple_strtoul(str, &str, 0);
return 1;
}
__setup("dhash_entries=", set_dhash_entries);
static void __init dcache_init_early(void)
{
/* If hashes are distributed across NUMA nodes, defer
* hash allocation until vmalloc space is available.
*/
if (hashdist)
return;
dentry_hashtable =
alloc_large_system_hash("Dentry cache",
sizeof(struct hlist_bl_head),
dhash_entries,
13,
HASH_EARLY | HASH_ZERO,
&d_hash_shift,
NULL,
0,
0);
d_hash_shift = 32 - d_hash_shift;
}
static void __init dcache_init(void)
{
/*
* A constructor could be added for stable state like the lists,
* but it is probably not worth it because of the cache nature
* of the dcache.
*/
dentry_cache = KMEM_CACHE_USERCOPY(dentry,
SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
d_iname);
/* Hash may have been set up in dcache_init_early */
if (!hashdist)
return;
dentry_hashtable =
alloc_large_system_hash("Dentry cache",
sizeof(struct hlist_bl_head),
dhash_entries,
13,
HASH_ZERO,
&d_hash_shift,
NULL,
0,
0);
d_hash_shift = 32 - d_hash_shift;
}
/* SLAB cache for __getname() consumers */
struct kmem_cache *names_cachep __read_mostly;
EXPORT_SYMBOL(names_cachep);
void __init vfs_caches_init_early(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(in_lookup_hashtable); i++)
INIT_HLIST_BL_HEAD(&in_lookup_hashtable[i]);
dcache_init_early();
inode_init_early();
}
void __init vfs_caches_init(void)
{
names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL);
dcache_init();
inode_init();
files_init();
files_maxfiles_init();
mnt_init();
bdev_cache_init();
chrdev_init();
}
| linux-master | fs/dcache.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_bmap.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans.h"
#include "xfs_trans_space.h"
#include "xfs_icache.h"
#include "xfs_rtalloc.h"
#include "xfs_sb.h"
/*
* Read and return the summary information for a given extent size,
* bitmap block combination.
* Keeps track of a current summary block, so we don't keep reading
* it from the buffer cache.
*/
static int
xfs_rtget_summary(
xfs_mount_t *mp, /* file system mount structure */
xfs_trans_t *tp, /* transaction pointer */
int log, /* log2 of extent size */
xfs_rtblock_t bbno, /* bitmap block number */
struct xfs_buf **rbpp, /* in/out: summary block buffer */
xfs_fsblock_t *rsb, /* in/out: summary block number */
xfs_suminfo_t *sum) /* out: summary info for this block */
{
return xfs_rtmodify_summary_int(mp, tp, log, bbno, 0, rbpp, rsb, sum);
}
/*
* Return whether there are any free extents in the size range given
* by low and high, for the bitmap block bbno.
*/
STATIC int /* error */
xfs_rtany_summary(
xfs_mount_t *mp, /* file system mount structure */
xfs_trans_t *tp, /* transaction pointer */
int low, /* low log2 extent size */
int high, /* high log2 extent size */
xfs_rtblock_t bbno, /* bitmap block number */
struct xfs_buf **rbpp, /* in/out: summary block buffer */
xfs_fsblock_t *rsb, /* in/out: summary block number */
int *stat) /* out: any good extents here? */
{
int error; /* error value */
int log; /* loop counter, log2 of ext. size */
xfs_suminfo_t sum; /* summary data */
/* There are no extents at levels < m_rsum_cache[bbno]. */
if (mp->m_rsum_cache && low < mp->m_rsum_cache[bbno])
low = mp->m_rsum_cache[bbno];
/*
* Loop over logs of extent sizes.
*/
for (log = low; log <= high; log++) {
/*
* Get one summary datum.
*/
error = xfs_rtget_summary(mp, tp, log, bbno, rbpp, rsb, &sum);
if (error) {
return error;
}
/*
* If there are any, return success.
*/
if (sum) {
*stat = 1;
goto out;
}
}
/*
* Found nothing, return failure.
*/
*stat = 0;
out:
/* There were no extents at levels < log. */
if (mp->m_rsum_cache && log > mp->m_rsum_cache[bbno])
mp->m_rsum_cache[bbno] = log;
return 0;
}
/*
* Copy and transform the summary file, given the old and new
* parameters in the mount structures.
*/
STATIC int /* error */
xfs_rtcopy_summary(
xfs_mount_t *omp, /* old file system mount point */
xfs_mount_t *nmp, /* new file system mount point */
xfs_trans_t *tp) /* transaction pointer */
{
xfs_rtblock_t bbno; /* bitmap block number */
struct xfs_buf *bp; /* summary buffer */
int error; /* error return value */
int log; /* summary level number (log length) */
xfs_suminfo_t sum; /* summary data */
xfs_fsblock_t sumbno; /* summary block number */
bp = NULL;
for (log = omp->m_rsumlevels - 1; log >= 0; log--) {
for (bbno = omp->m_sb.sb_rbmblocks - 1;
(xfs_srtblock_t)bbno >= 0;
bbno--) {
error = xfs_rtget_summary(omp, tp, log, bbno, &bp,
&sumbno, &sum);
if (error)
return error;
if (sum == 0)
continue;
error = xfs_rtmodify_summary(omp, tp, log, bbno, -sum,
&bp, &sumbno);
if (error)
return error;
error = xfs_rtmodify_summary(nmp, tp, log, bbno, sum,
&bp, &sumbno);
if (error)
return error;
ASSERT(sum > 0);
}
}
return 0;
}
/*
* Mark an extent specified by start and len allocated.
* Updates all the summary information as well as the bitmap.
*/
STATIC int /* error */
xfs_rtallocate_range(
xfs_mount_t *mp, /* file system mount point */
xfs_trans_t *tp, /* transaction pointer */
xfs_rtblock_t start, /* start block to allocate */
xfs_extlen_t len, /* length to allocate */
struct xfs_buf **rbpp, /* in/out: summary block buffer */
xfs_fsblock_t *rsb) /* in/out: summary block number */
{
xfs_rtblock_t end; /* end of the allocated extent */
int error; /* error value */
xfs_rtblock_t postblock = 0; /* first block allocated > end */
xfs_rtblock_t preblock = 0; /* first block allocated < start */
end = start + len - 1;
/*
* Assume we're allocating out of the middle of a free extent.
* We need to find the beginning and end of the extent so we can
* properly update the summary.
*/
error = xfs_rtfind_back(mp, tp, start, 0, &preblock);
if (error) {
return error;
}
/*
* Find the next allocated block (end of free extent).
*/
error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1,
&postblock);
if (error) {
return error;
}
/*
* Decrement the summary information corresponding to the entire
* (old) free extent.
*/
error = xfs_rtmodify_summary(mp, tp,
XFS_RTBLOCKLOG(postblock + 1 - preblock),
XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb);
if (error) {
return error;
}
/*
* If there are blocks not being allocated at the front of the
* old extent, add summary data for them to be free.
*/
if (preblock < start) {
error = xfs_rtmodify_summary(mp, tp,
XFS_RTBLOCKLOG(start - preblock),
XFS_BITTOBLOCK(mp, preblock), 1, rbpp, rsb);
if (error) {
return error;
}
}
/*
* If there are blocks not being allocated at the end of the
* old extent, add summary data for them to be free.
*/
if (postblock > end) {
error = xfs_rtmodify_summary(mp, tp,
XFS_RTBLOCKLOG(postblock - end),
XFS_BITTOBLOCK(mp, end + 1), 1, rbpp, rsb);
if (error) {
return error;
}
}
/*
* Modify the bitmap to mark this extent allocated.
*/
error = xfs_rtmodify_range(mp, tp, start, len, 0);
return error;
}
/*
* Attempt to allocate an extent minlen<=len<=maxlen starting from
* bitmap block bbno. If we don't get maxlen then use prod to trim
* the length, if given. Returns error; returns starting block in *rtblock.
* The lengths are all in rtextents.
*/
STATIC int /* error */
xfs_rtallocate_extent_block(
xfs_mount_t *mp, /* file system mount point */
xfs_trans_t *tp, /* transaction pointer */
xfs_rtblock_t bbno, /* bitmap block number */
xfs_extlen_t minlen, /* minimum length to allocate */
xfs_extlen_t maxlen, /* maximum length to allocate */
xfs_extlen_t *len, /* out: actual length allocated */
xfs_rtblock_t *nextp, /* out: next block to try */
struct xfs_buf **rbpp, /* in/out: summary block buffer */
xfs_fsblock_t *rsb, /* in/out: summary block number */
xfs_extlen_t prod, /* extent product factor */
xfs_rtblock_t *rtblock) /* out: start block allocated */
{
xfs_rtblock_t besti; /* best rtblock found so far */
xfs_rtblock_t bestlen; /* best length found so far */
xfs_rtblock_t end; /* last rtblock in chunk */
int error; /* error value */
xfs_rtblock_t i; /* current rtblock trying */
xfs_rtblock_t next; /* next rtblock to try */
int stat; /* status from internal calls */
/*
* Loop over all the extents starting in this bitmap block,
* looking for one that's long enough.
*/
for (i = XFS_BLOCKTOBIT(mp, bbno), besti = -1, bestlen = 0,
end = XFS_BLOCKTOBIT(mp, bbno + 1) - 1;
i <= end;
i++) {
/* Make sure we don't scan off the end of the rt volume. */
maxlen = min(mp->m_sb.sb_rextents, i + maxlen) - i;
/*
* See if there's a free extent of maxlen starting at i.
* If it's not so then next will contain the first non-free.
*/
error = xfs_rtcheck_range(mp, tp, i, maxlen, 1, &next, &stat);
if (error) {
return error;
}
if (stat) {
/*
* i for maxlen is all free, allocate and return that.
*/
error = xfs_rtallocate_range(mp, tp, i, maxlen, rbpp,
rsb);
if (error) {
return error;
}
*len = maxlen;
*rtblock = i;
return 0;
}
/*
* In the case where we have a variable-sized allocation
* request, figure out how big this free piece is,
* and if it's big enough for the minimum, and the best
* so far, remember it.
*/
if (minlen < maxlen) {
xfs_rtblock_t thislen; /* this extent size */
thislen = next - i;
if (thislen >= minlen && thislen > bestlen) {
besti = i;
bestlen = thislen;
}
}
/*
* If not done yet, find the start of the next free space.
*/
if (next < end) {
error = xfs_rtfind_forw(mp, tp, next, end, &i);
if (error) {
return error;
}
} else
break;
}
/*
* Searched the whole thing & didn't find a maxlen free extent.
*/
if (minlen < maxlen && besti != -1) {
xfs_extlen_t p; /* amount to trim length by */
/*
* If size should be a multiple of prod, make that so.
*/
if (prod > 1) {
div_u64_rem(bestlen, prod, &p);
if (p)
bestlen -= p;
}
/*
* Allocate besti for bestlen & return that.
*/
error = xfs_rtallocate_range(mp, tp, besti, bestlen, rbpp, rsb);
if (error) {
return error;
}
*len = bestlen;
*rtblock = besti;
return 0;
}
/*
* Allocation failed. Set *nextp to the next block to try.
*/
*nextp = next;
*rtblock = NULLRTBLOCK;
return 0;
}
/*
* Allocate an extent of length minlen<=len<=maxlen, starting at block
* bno. If we don't get maxlen then use prod to trim the length, if given.
* Returns error; returns starting block in *rtblock.
* The lengths are all in rtextents.
*/
STATIC int /* error */
xfs_rtallocate_extent_exact(
xfs_mount_t *mp, /* file system mount point */
xfs_trans_t *tp, /* transaction pointer */
xfs_rtblock_t bno, /* starting block number to allocate */
xfs_extlen_t minlen, /* minimum length to allocate */
xfs_extlen_t maxlen, /* maximum length to allocate */
xfs_extlen_t *len, /* out: actual length allocated */
struct xfs_buf **rbpp, /* in/out: summary block buffer */
xfs_fsblock_t *rsb, /* in/out: summary block number */
xfs_extlen_t prod, /* extent product factor */
xfs_rtblock_t *rtblock) /* out: start block allocated */
{
int error; /* error value */
xfs_extlen_t i; /* extent length trimmed due to prod */
int isfree; /* extent is free */
xfs_rtblock_t next; /* next block to try (dummy) */
ASSERT(minlen % prod == 0 && maxlen % prod == 0);
/*
* Check if the range in question (for maxlen) is free.
*/
error = xfs_rtcheck_range(mp, tp, bno, maxlen, 1, &next, &isfree);
if (error) {
return error;
}
if (isfree) {
/*
* If it is, allocate it and return success.
*/
error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
if (error) {
return error;
}
*len = maxlen;
*rtblock = bno;
return 0;
}
/*
* If not, allocate what there is, if it's at least minlen.
*/
maxlen = next - bno;
if (maxlen < minlen) {
/*
* Failed, return failure status.
*/
*rtblock = NULLRTBLOCK;
return 0;
}
/*
* Trim off tail of extent, if prod is specified.
*/
if (prod > 1 && (i = maxlen % prod)) {
maxlen -= i;
if (maxlen < minlen) {
/*
* Now we can't do it, return failure status.
*/
*rtblock = NULLRTBLOCK;
return 0;
}
}
/*
* Allocate what we can and return it.
*/
error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
if (error) {
return error;
}
*len = maxlen;
*rtblock = bno;
return 0;
}
/*
* Allocate an extent of length minlen<=len<=maxlen, starting as near
* to bno as possible. If we don't get maxlen then use prod to trim
* the length, if given. The lengths are all in rtextents.
*/
STATIC int /* error */
xfs_rtallocate_extent_near(
xfs_mount_t *mp, /* file system mount point */
xfs_trans_t *tp, /* transaction pointer */
xfs_rtblock_t bno, /* starting block number to allocate */
xfs_extlen_t minlen, /* minimum length to allocate */
xfs_extlen_t maxlen, /* maximum length to allocate */
xfs_extlen_t *len, /* out: actual length allocated */
struct xfs_buf **rbpp, /* in/out: summary block buffer */
xfs_fsblock_t *rsb, /* in/out: summary block number */
xfs_extlen_t prod, /* extent product factor */
xfs_rtblock_t *rtblock) /* out: start block allocated */
{
int any; /* any useful extents from summary */
xfs_rtblock_t bbno; /* bitmap block number */
int error; /* error value */
int i; /* bitmap block offset (loop control) */
int j; /* secondary loop control */
int log2len; /* log2 of minlen */
xfs_rtblock_t n; /* next block to try */
xfs_rtblock_t r; /* result block */
ASSERT(minlen % prod == 0 && maxlen % prod == 0);
/*
* If the block number given is off the end, silently set it to
* the last block.
*/
if (bno >= mp->m_sb.sb_rextents)
bno = mp->m_sb.sb_rextents - 1;
/* Make sure we don't run off the end of the rt volume. */
maxlen = min(mp->m_sb.sb_rextents, bno + maxlen) - bno;
if (maxlen < minlen) {
*rtblock = NULLRTBLOCK;
return 0;
}
/*
* Try the exact allocation first.
*/
error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen, len,
rbpp, rsb, prod, &r);
if (error) {
return error;
}
/*
* If the exact allocation worked, return that.
*/
if (r != NULLRTBLOCK) {
*rtblock = r;
return 0;
}
bbno = XFS_BITTOBLOCK(mp, bno);
i = 0;
ASSERT(minlen != 0);
log2len = xfs_highbit32(minlen);
/*
* Loop over all bitmap blocks (bbno + i is current block).
*/
for (;;) {
/*
* Get summary information of extents of all useful levels
* starting in this bitmap block.
*/
error = xfs_rtany_summary(mp, tp, log2len, mp->m_rsumlevels - 1,
bbno + i, rbpp, rsb, &any);
if (error) {
return error;
}
/*
* If there are any useful extents starting here, try
* allocating one.
*/
if (any) {
/*
* On the positive side of the starting location.
*/
if (i >= 0) {
/*
* Try to allocate an extent starting in
* this block.
*/
error = xfs_rtallocate_extent_block(mp, tp,
bbno + i, minlen, maxlen, len, &n, rbpp,
rsb, prod, &r);
if (error) {
return error;
}
/*
* If it worked, return it.
*/
if (r != NULLRTBLOCK) {
*rtblock = r;
return 0;
}
}
/*
* On the negative side of the starting location.
*/
else { /* i < 0 */
/*
* Loop backwards through the bitmap blocks from
* the starting point-1 up to where we are now.
* There should be an extent which ends in this
* bitmap block and is long enough.
*/
for (j = -1; j > i; j--) {
/*
* Grab the summary information for
* this bitmap block.
*/
error = xfs_rtany_summary(mp, tp,
log2len, mp->m_rsumlevels - 1,
bbno + j, rbpp, rsb, &any);
if (error) {
return error;
}
/*
* If there's no extent given in the
* summary that means the extent we
* found must carry over from an
* earlier block. If there is an
* extent given, we've already tried
* that allocation, don't do it again.
*/
if (any)
continue;
error = xfs_rtallocate_extent_block(mp,
tp, bbno + j, minlen, maxlen,
len, &n, rbpp, rsb, prod, &r);
if (error) {
return error;
}
/*
* If it works, return the extent.
*/
if (r != NULLRTBLOCK) {
*rtblock = r;
return 0;
}
}
/*
* There weren't intervening bitmap blocks
* with a long enough extent, or the
* allocation didn't work for some reason
* (i.e. it's a little * too short).
* Try to allocate from the summary block
* that we found.
*/
error = xfs_rtallocate_extent_block(mp, tp,
bbno + i, minlen, maxlen, len, &n, rbpp,
rsb, prod, &r);
if (error) {
return error;
}
/*
* If it works, return the extent.
*/
if (r != NULLRTBLOCK) {
*rtblock = r;
return 0;
}
}
}
/*
* Loop control. If we were on the positive side, and there's
* still more blocks on the negative side, go there.
*/
if (i > 0 && (int)bbno - i >= 0)
i = -i;
/*
* If positive, and no more negative, but there are more
* positive, go there.
*/
else if (i > 0 && (int)bbno + i < mp->m_sb.sb_rbmblocks - 1)
i++;
/*
* If negative or 0 (just started), and there are positive
* blocks to go, go there. The 0 case moves to block 1.
*/
else if (i <= 0 && (int)bbno - i < mp->m_sb.sb_rbmblocks - 1)
i = 1 - i;
/*
* If negative or 0 and there are more negative blocks,
* go there.
*/
else if (i <= 0 && (int)bbno + i > 0)
i--;
/*
* Must be done. Return failure.
*/
else
break;
}
*rtblock = NULLRTBLOCK;
return 0;
}
/*
* Allocate an extent of length minlen<=len<=maxlen, with no position
* specified. If we don't get maxlen then use prod to trim
* the length, if given. The lengths are all in rtextents.
*/
STATIC int /* error */
xfs_rtallocate_extent_size(
xfs_mount_t *mp, /* file system mount point */
xfs_trans_t *tp, /* transaction pointer */
xfs_extlen_t minlen, /* minimum length to allocate */
xfs_extlen_t maxlen, /* maximum length to allocate */
xfs_extlen_t *len, /* out: actual length allocated */
struct xfs_buf **rbpp, /* in/out: summary block buffer */
xfs_fsblock_t *rsb, /* in/out: summary block number */
xfs_extlen_t prod, /* extent product factor */
xfs_rtblock_t *rtblock) /* out: start block allocated */
{
int error; /* error value */
int i; /* bitmap block number */
int l; /* level number (loop control) */
xfs_rtblock_t n; /* next block to be tried */
xfs_rtblock_t r; /* result block number */
xfs_suminfo_t sum; /* summary information for extents */
ASSERT(minlen % prod == 0 && maxlen % prod == 0);
ASSERT(maxlen != 0);
/*
* Loop over all the levels starting with maxlen.
* At each level, look at all the bitmap blocks, to see if there
* are extents starting there that are long enough (>= maxlen).
* Note, only on the initial level can the allocation fail if
* the summary says there's an extent.
*/
for (l = xfs_highbit32(maxlen); l < mp->m_rsumlevels; l++) {
/*
* Loop over all the bitmap blocks.
*/
for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
/*
* Get the summary for this level/block.
*/
error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
&sum);
if (error) {
return error;
}
/*
* Nothing there, on to the next block.
*/
if (!sum)
continue;
/*
* Try allocating the extent.
*/
error = xfs_rtallocate_extent_block(mp, tp, i, maxlen,
maxlen, len, &n, rbpp, rsb, prod, &r);
if (error) {
return error;
}
/*
* If it worked, return that.
*/
if (r != NULLRTBLOCK) {
*rtblock = r;
return 0;
}
/*
* If the "next block to try" returned from the
* allocator is beyond the next bitmap block,
* skip to that bitmap block.
*/
if (XFS_BITTOBLOCK(mp, n) > i + 1)
i = XFS_BITTOBLOCK(mp, n) - 1;
}
}
/*
* Didn't find any maxlen blocks. Try smaller ones, unless
* we're asking for a fixed size extent.
*/
if (minlen > --maxlen) {
*rtblock = NULLRTBLOCK;
return 0;
}
ASSERT(minlen != 0);
ASSERT(maxlen != 0);
/*
* Loop over sizes, from maxlen down to minlen.
* This time, when we do the allocations, allow smaller ones
* to succeed.
*/
for (l = xfs_highbit32(maxlen); l >= xfs_highbit32(minlen); l--) {
/*
* Loop over all the bitmap blocks, try an allocation
* starting in that block.
*/
for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
/*
* Get the summary information for this level/block.
*/
error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
&sum);
if (error) {
return error;
}
/*
* If nothing there, go on to next.
*/
if (!sum)
continue;
/*
* Try the allocation. Make sure the specified
* minlen/maxlen are in the possible range for
* this summary level.
*/
error = xfs_rtallocate_extent_block(mp, tp, i,
XFS_RTMAX(minlen, 1 << l),
XFS_RTMIN(maxlen, (1 << (l + 1)) - 1),
len, &n, rbpp, rsb, prod, &r);
if (error) {
return error;
}
/*
* If it worked, return that extent.
*/
if (r != NULLRTBLOCK) {
*rtblock = r;
return 0;
}
/*
* If the "next block to try" returned from the
* allocator is beyond the next bitmap block,
* skip to that bitmap block.
*/
if (XFS_BITTOBLOCK(mp, n) > i + 1)
i = XFS_BITTOBLOCK(mp, n) - 1;
}
}
/*
* Got nothing, return failure.
*/
*rtblock = NULLRTBLOCK;
return 0;
}
/*
* Allocate space to the bitmap or summary file, and zero it, for growfs.
*/
STATIC int
xfs_growfs_rt_alloc(
struct xfs_mount *mp, /* file system mount point */
xfs_extlen_t oblocks, /* old count of blocks */
xfs_extlen_t nblocks, /* new count of blocks */
struct xfs_inode *ip) /* inode (bitmap/summary) */
{
xfs_fileoff_t bno; /* block number in file */
struct xfs_buf *bp; /* temporary buffer for zeroing */
xfs_daddr_t d; /* disk block address */
int error; /* error return value */
xfs_fsblock_t fsbno; /* filesystem block for bno */
struct xfs_bmbt_irec map; /* block map output */
int nmap; /* number of block maps */
int resblks; /* space reservation */
enum xfs_blft buf_type;
struct xfs_trans *tp;
if (ip == mp->m_rsumip)
buf_type = XFS_BLFT_RTSUMMARY_BUF;
else
buf_type = XFS_BLFT_RTBITMAP_BUF;
/*
* Allocate space to the file, as necessary.
*/
while (oblocks < nblocks) {
resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks);
/*
* Reserve space & log for one extent added to the file.
*/
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtalloc, resblks,
0, 0, &tp);
if (error)
return error;
/*
* Lock the inode.
*/
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_ADD_NOSPLIT_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip,
XFS_IEXT_ADD_NOSPLIT_CNT);
if (error)
goto out_trans_cancel;
/*
* Allocate blocks to the bitmap file.
*/
nmap = 1;
error = xfs_bmapi_write(tp, ip, oblocks, nblocks - oblocks,
XFS_BMAPI_METADATA, 0, &map, &nmap);
if (!error && nmap < 1)
error = -ENOSPC;
if (error)
goto out_trans_cancel;
/*
* Free any blocks freed up in the transaction, then commit.
*/
error = xfs_trans_commit(tp);
if (error)
return error;
/*
* Now we need to clear the allocated blocks.
* Do this one block per transaction, to keep it simple.
*/
for (bno = map.br_startoff, fsbno = map.br_startblock;
bno < map.br_startoff + map.br_blockcount;
bno++, fsbno++) {
/*
* Reserve log for one block zeroing.
*/
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtzero,
0, 0, 0, &tp);
if (error)
return error;
/*
* Lock the bitmap inode.
*/
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
/*
* Get a buffer for the block.
*/
d = XFS_FSB_TO_DADDR(mp, fsbno);
error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
mp->m_bsize, 0, &bp);
if (error)
goto out_trans_cancel;
xfs_trans_buf_set_type(tp, bp, buf_type);
bp->b_ops = &xfs_rtbuf_ops;
memset(bp->b_addr, 0, mp->m_sb.sb_blocksize);
xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
/*
* Commit the transaction.
*/
error = xfs_trans_commit(tp);
if (error)
return error;
}
/*
* Go on to the next extent, if any.
*/
oblocks = map.br_startoff + map.br_blockcount;
}
return 0;
out_trans_cancel:
xfs_trans_cancel(tp);
return error;
}
static void
xfs_alloc_rsum_cache(
xfs_mount_t *mp, /* file system mount structure */
xfs_extlen_t rbmblocks) /* number of rt bitmap blocks */
{
/*
* The rsum cache is initialized to all zeroes, which is trivially a
* lower bound on the minimum level with any free extents. We can
* continue without the cache if it couldn't be allocated.
*/
mp->m_rsum_cache = kvzalloc(rbmblocks, GFP_KERNEL);
if (!mp->m_rsum_cache)
xfs_warn(mp, "could not allocate realtime summary cache");
}
/*
* Visible (exported) functions.
*/
/*
* Grow the realtime area of the filesystem.
*/
int
xfs_growfs_rt(
xfs_mount_t *mp, /* mount point for filesystem */
xfs_growfs_rt_t *in) /* growfs rt input struct */
{
xfs_rtblock_t bmbno; /* bitmap block number */
struct xfs_buf *bp; /* temporary buffer */
int error; /* error return value */
xfs_mount_t *nmp; /* new (fake) mount structure */
xfs_rfsblock_t nrblocks; /* new number of realtime blocks */
xfs_extlen_t nrbmblocks; /* new number of rt bitmap blocks */
xfs_rtblock_t nrextents; /* new number of realtime extents */
uint8_t nrextslog; /* new log2 of sb_rextents */
xfs_extlen_t nrsumblocks; /* new number of summary blocks */
uint nrsumlevels; /* new rt summary levels */
uint nrsumsize; /* new size of rt summary, bytes */
xfs_sb_t *nsbp; /* new superblock */
xfs_extlen_t rbmblocks; /* current number of rt bitmap blocks */
xfs_extlen_t rsumblocks; /* current number of rt summary blks */
xfs_sb_t *sbp; /* old superblock */
xfs_fsblock_t sumbno; /* summary block number */
uint8_t *rsum_cache; /* old summary cache */
sbp = &mp->m_sb;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/* Needs to have been mounted with an rt device. */
if (!XFS_IS_REALTIME_MOUNT(mp))
return -EINVAL;
/*
* Mount should fail if the rt bitmap/summary files don't load, but
* we'll check anyway.
*/
if (!mp->m_rbmip || !mp->m_rsumip)
return -EINVAL;
/* Shrink not supported. */
if (in->newblocks <= sbp->sb_rblocks)
return -EINVAL;
/* Can only change rt extent size when adding rt volume. */
if (sbp->sb_rblocks > 0 && in->extsize != sbp->sb_rextsize)
return -EINVAL;
/* Range check the extent size. */
if (XFS_FSB_TO_B(mp, in->extsize) > XFS_MAX_RTEXTSIZE ||
XFS_FSB_TO_B(mp, in->extsize) < XFS_MIN_RTEXTSIZE)
return -EINVAL;
/* Unsupported realtime features. */
if (xfs_has_rmapbt(mp) || xfs_has_reflink(mp))
return -EOPNOTSUPP;
nrblocks = in->newblocks;
error = xfs_sb_validate_fsb_count(sbp, nrblocks);
if (error)
return error;
/*
* Read in the last block of the device, make sure it exists.
*/
error = xfs_buf_read_uncached(mp->m_rtdev_targp,
XFS_FSB_TO_BB(mp, nrblocks - 1),
XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
if (error)
return error;
xfs_buf_relse(bp);
/*
* Calculate new parameters. These are the final values to be reached.
*/
nrextents = nrblocks;
do_div(nrextents, in->extsize);
nrbmblocks = howmany_64(nrextents, NBBY * sbp->sb_blocksize);
nrextslog = xfs_highbit32(nrextents);
nrsumlevels = nrextslog + 1;
nrsumsize = (uint)sizeof(xfs_suminfo_t) * nrsumlevels * nrbmblocks;
nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
/*
* New summary size can't be more than half the size of
* the log. This prevents us from getting a log overflow,
* since we'll log basically the whole summary file at once.
*/
if (nrsumblocks > (mp->m_sb.sb_logblocks >> 1))
return -EINVAL;
/*
* Get the old block counts for bitmap and summary inodes.
* These can't change since other growfs callers are locked out.
*/
rbmblocks = XFS_B_TO_FSB(mp, mp->m_rbmip->i_disk_size);
rsumblocks = XFS_B_TO_FSB(mp, mp->m_rsumip->i_disk_size);
/*
* Allocate space to the bitmap and summary files, as necessary.
*/
error = xfs_growfs_rt_alloc(mp, rbmblocks, nrbmblocks, mp->m_rbmip);
if (error)
return error;
error = xfs_growfs_rt_alloc(mp, rsumblocks, nrsumblocks, mp->m_rsumip);
if (error)
return error;
rsum_cache = mp->m_rsum_cache;
if (nrbmblocks != sbp->sb_rbmblocks)
xfs_alloc_rsum_cache(mp, nrbmblocks);
/*
* Allocate a new (fake) mount/sb.
*/
nmp = kmem_alloc(sizeof(*nmp), 0);
/*
* Loop over the bitmap blocks.
* We will do everything one bitmap block at a time.
* Skip the current block if it is exactly full.
* This also deals with the case where there were no rtextents before.
*/
for (bmbno = sbp->sb_rbmblocks -
((sbp->sb_rextents & ((1 << mp->m_blkbit_log) - 1)) != 0);
bmbno < nrbmblocks;
bmbno++) {
struct xfs_trans *tp;
xfs_rfsblock_t nrblocks_step;
*nmp = *mp;
nsbp = &nmp->m_sb;
/*
* Calculate new sb and mount fields for this round.
*/
nsbp->sb_rextsize = in->extsize;
nsbp->sb_rbmblocks = bmbno + 1;
nrblocks_step = (bmbno + 1) * NBBY * nsbp->sb_blocksize *
nsbp->sb_rextsize;
nsbp->sb_rblocks = min(nrblocks, nrblocks_step);
nsbp->sb_rextents = nsbp->sb_rblocks;
do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
ASSERT(nsbp->sb_rextents != 0);
nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;
nrsumsize =
(uint)sizeof(xfs_suminfo_t) * nrsumlevels *
nsbp->sb_rbmblocks;
nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
nmp->m_rsumsize = nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
/*
* Start a transaction, get the log reservation.
*/
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtfree, 0, 0, 0,
&tp);
if (error)
break;
/*
* Lock out other callers by grabbing the bitmap inode lock.
*/
xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL | XFS_ILOCK_RTBITMAP);
xfs_trans_ijoin(tp, mp->m_rbmip, XFS_ILOCK_EXCL);
/*
* Update the bitmap inode's size ondisk and incore. We need
* to update the incore size so that inode inactivation won't
* punch what it thinks are "posteof" blocks.
*/
mp->m_rbmip->i_disk_size =
nsbp->sb_rbmblocks * nsbp->sb_blocksize;
i_size_write(VFS_I(mp->m_rbmip), mp->m_rbmip->i_disk_size);
xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
/*
* Get the summary inode into the transaction.
*/
xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL | XFS_ILOCK_RTSUM);
xfs_trans_ijoin(tp, mp->m_rsumip, XFS_ILOCK_EXCL);
/*
* Update the summary inode's size. We need to update the
* incore size so that inode inactivation won't punch what it
* thinks are "posteof" blocks.
*/
mp->m_rsumip->i_disk_size = nmp->m_rsumsize;
i_size_write(VFS_I(mp->m_rsumip), mp->m_rsumip->i_disk_size);
xfs_trans_log_inode(tp, mp->m_rsumip, XFS_ILOG_CORE);
/*
* Copy summary data from old to new sizes.
* Do this when the real size (not block-aligned) changes.
*/
if (sbp->sb_rbmblocks != nsbp->sb_rbmblocks ||
mp->m_rsumlevels != nmp->m_rsumlevels) {
error = xfs_rtcopy_summary(mp, nmp, tp);
if (error)
goto error_cancel;
}
/*
* Update superblock fields.
*/
if (nsbp->sb_rextsize != sbp->sb_rextsize)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSIZE,
nsbp->sb_rextsize - sbp->sb_rextsize);
if (nsbp->sb_rbmblocks != sbp->sb_rbmblocks)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBMBLOCKS,
nsbp->sb_rbmblocks - sbp->sb_rbmblocks);
if (nsbp->sb_rblocks != sbp->sb_rblocks)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBLOCKS,
nsbp->sb_rblocks - sbp->sb_rblocks);
if (nsbp->sb_rextents != sbp->sb_rextents)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTENTS,
nsbp->sb_rextents - sbp->sb_rextents);
if (nsbp->sb_rextslog != sbp->sb_rextslog)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSLOG,
nsbp->sb_rextslog - sbp->sb_rextslog);
/*
* Free new extent.
*/
bp = NULL;
error = xfs_rtfree_range(nmp, tp, sbp->sb_rextents,
nsbp->sb_rextents - sbp->sb_rextents, &bp, &sumbno);
if (error) {
error_cancel:
xfs_trans_cancel(tp);
break;
}
/*
* Mark more blocks free in the superblock.
*/
xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS,
nsbp->sb_rextents - sbp->sb_rextents);
/*
* Update mp values into the real mp structure.
*/
mp->m_rsumlevels = nrsumlevels;
mp->m_rsumsize = nrsumsize;
error = xfs_trans_commit(tp);
if (error)
break;
/* Ensure the mount RT feature flag is now set. */
mp->m_features |= XFS_FEAT_REALTIME;
}
if (error)
goto out_free;
/* Update secondary superblocks now the physical grow has completed */
error = xfs_update_secondary_sbs(mp);
out_free:
/*
* Free the fake mp structure.
*/
kmem_free(nmp);
/*
* If we had to allocate a new rsum_cache, we either need to free the
* old one (if we succeeded) or free the new one and restore the old one
* (if there was an error).
*/
if (rsum_cache != mp->m_rsum_cache) {
if (error) {
kmem_free(mp->m_rsum_cache);
mp->m_rsum_cache = rsum_cache;
} else {
kmem_free(rsum_cache);
}
}
return error;
}
/*
* Allocate an extent in the realtime subvolume, with the usual allocation
* parameters. The length units are all in realtime extents, as is the
* result block number.
*/
int /* error */
xfs_rtallocate_extent(
xfs_trans_t *tp, /* transaction pointer */
xfs_rtblock_t bno, /* starting block number to allocate */
xfs_extlen_t minlen, /* minimum length to allocate */
xfs_extlen_t maxlen, /* maximum length to allocate */
xfs_extlen_t *len, /* out: actual length allocated */
int wasdel, /* was a delayed allocation extent */
xfs_extlen_t prod, /* extent product factor */
xfs_rtblock_t *rtblock) /* out: start block allocated */
{
xfs_mount_t *mp = tp->t_mountp;
int error; /* error value */
xfs_rtblock_t r; /* result allocated block */
xfs_fsblock_t sb; /* summary file block number */
struct xfs_buf *sumbp; /* summary file block buffer */
ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
ASSERT(minlen > 0 && minlen <= maxlen);
/*
* If prod is set then figure out what to do to minlen and maxlen.
*/
if (prod > 1) {
xfs_extlen_t i;
if ((i = maxlen % prod))
maxlen -= i;
if ((i = minlen % prod))
minlen += prod - i;
if (maxlen < minlen) {
*rtblock = NULLRTBLOCK;
return 0;
}
}
retry:
sumbp = NULL;
if (bno == 0) {
error = xfs_rtallocate_extent_size(mp, tp, minlen, maxlen, len,
&sumbp, &sb, prod, &r);
} else {
error = xfs_rtallocate_extent_near(mp, tp, bno, minlen, maxlen,
len, &sumbp, &sb, prod, &r);
}
if (error)
return error;
/*
* If it worked, update the superblock.
*/
if (r != NULLRTBLOCK) {
long slen = (long)*len;
ASSERT(*len >= minlen && *len <= maxlen);
if (wasdel)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FREXTENTS, -slen);
else
xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, -slen);
} else if (prod > 1) {
prod = 1;
goto retry;
}
*rtblock = r;
return 0;
}
/*
* Initialize realtime fields in the mount structure.
*/
int /* error */
xfs_rtmount_init(
struct xfs_mount *mp) /* file system mount structure */
{
struct xfs_buf *bp; /* buffer for last block of subvolume */
struct xfs_sb *sbp; /* filesystem superblock copy in mount */
xfs_daddr_t d; /* address of last block of subvolume */
int error;
sbp = &mp->m_sb;
if (sbp->sb_rblocks == 0)
return 0;
if (mp->m_rtdev_targp == NULL) {
xfs_warn(mp,
"Filesystem has a realtime volume, use rtdev=device option");
return -ENODEV;
}
mp->m_rsumlevels = sbp->sb_rextslog + 1;
mp->m_rsumsize =
(uint)sizeof(xfs_suminfo_t) * mp->m_rsumlevels *
sbp->sb_rbmblocks;
mp->m_rsumsize = roundup(mp->m_rsumsize, sbp->sb_blocksize);
mp->m_rbmip = mp->m_rsumip = NULL;
/*
* Check that the realtime section is an ok size.
*/
d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_rblocks) {
xfs_warn(mp, "realtime mount -- %llu != %llu",
(unsigned long long) XFS_BB_TO_FSB(mp, d),
(unsigned long long) mp->m_sb.sb_rblocks);
return -EFBIG;
}
error = xfs_buf_read_uncached(mp->m_rtdev_targp,
d - XFS_FSB_TO_BB(mp, 1),
XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
if (error) {
xfs_warn(mp, "realtime device size check failed");
return error;
}
xfs_buf_relse(bp);
return 0;
}
static int
xfs_rtalloc_count_frextent(
struct xfs_mount *mp,
struct xfs_trans *tp,
const struct xfs_rtalloc_rec *rec,
void *priv)
{
uint64_t *valp = priv;
*valp += rec->ar_extcount;
return 0;
}
/*
* Reinitialize the number of free realtime extents from the realtime bitmap.
* Callers must ensure that there is no other activity in the filesystem.
*/
int
xfs_rtalloc_reinit_frextents(
struct xfs_mount *mp)
{
uint64_t val = 0;
int error;
xfs_ilock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
error = xfs_rtalloc_query_all(mp, NULL, xfs_rtalloc_count_frextent,
&val);
xfs_iunlock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
if (error)
return error;
spin_lock(&mp->m_sb_lock);
mp->m_sb.sb_frextents = val;
spin_unlock(&mp->m_sb_lock);
percpu_counter_set(&mp->m_frextents, mp->m_sb.sb_frextents);
return 0;
}
/*
* Read in the bmbt of an rt metadata inode so that we never have to load them
* at runtime. This enables the use of shared ILOCKs for rtbitmap scans. Use
* an empty transaction to avoid deadlocking on loops in the bmbt.
*/
static inline int
xfs_rtmount_iread_extents(
struct xfs_inode *ip,
unsigned int lock_class)
{
struct xfs_trans *tp;
int error;
error = xfs_trans_alloc_empty(ip->i_mount, &tp);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_EXCL | lock_class);
error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
if (error)
goto out_unlock;
if (xfs_inode_has_attr_fork(ip)) {
error = xfs_iread_extents(tp, ip, XFS_ATTR_FORK);
if (error)
goto out_unlock;
}
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL | lock_class);
xfs_trans_cancel(tp);
return error;
}
/*
* Get the bitmap and summary inodes and the summary cache into the mount
* structure at mount time.
*/
int /* error */
xfs_rtmount_inodes(
xfs_mount_t *mp) /* file system mount structure */
{
int error; /* error return value */
xfs_sb_t *sbp;
sbp = &mp->m_sb;
error = xfs_iget(mp, NULL, sbp->sb_rbmino, 0, 0, &mp->m_rbmip);
if (error)
return error;
ASSERT(mp->m_rbmip != NULL);
error = xfs_rtmount_iread_extents(mp->m_rbmip, XFS_ILOCK_RTBITMAP);
if (error)
goto out_rele_bitmap;
error = xfs_iget(mp, NULL, sbp->sb_rsumino, 0, 0, &mp->m_rsumip);
if (error)
goto out_rele_bitmap;
ASSERT(mp->m_rsumip != NULL);
error = xfs_rtmount_iread_extents(mp->m_rsumip, XFS_ILOCK_RTSUM);
if (error)
goto out_rele_summary;
xfs_alloc_rsum_cache(mp, sbp->sb_rbmblocks);
return 0;
out_rele_summary:
xfs_irele(mp->m_rsumip);
out_rele_bitmap:
xfs_irele(mp->m_rbmip);
return error;
}
void
xfs_rtunmount_inodes(
struct xfs_mount *mp)
{
kmem_free(mp->m_rsum_cache);
if (mp->m_rbmip)
xfs_irele(mp->m_rbmip);
if (mp->m_rsumip)
xfs_irele(mp->m_rsumip);
}
/*
* Pick an extent for allocation at the start of a new realtime file.
* Use the sequence number stored in the atime field of the bitmap inode.
* Translate this to a fraction of the rtextents, and return the product
* of rtextents and the fraction.
* The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
*/
int /* error */
xfs_rtpick_extent(
xfs_mount_t *mp, /* file system mount point */
xfs_trans_t *tp, /* transaction pointer */
xfs_extlen_t len, /* allocation length (rtextents) */
xfs_rtblock_t *pick) /* result rt extent */
{
xfs_rtblock_t b; /* result block */
int log2; /* log of sequence number */
uint64_t resid; /* residual after log removed */
uint64_t seq; /* sequence number of file creation */
uint64_t *seqp; /* pointer to seqno in inode */
ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
seqp = (uint64_t *)&VFS_I(mp->m_rbmip)->i_atime;
if (!(mp->m_rbmip->i_diflags & XFS_DIFLAG_NEWRTBM)) {
mp->m_rbmip->i_diflags |= XFS_DIFLAG_NEWRTBM;
*seqp = 0;
}
seq = *seqp;
if ((log2 = xfs_highbit64(seq)) == -1)
b = 0;
else {
resid = seq - (1ULL << log2);
b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
(log2 + 1);
if (b >= mp->m_sb.sb_rextents)
div64_u64_rem(b, mp->m_sb.sb_rextents, &b);
if (b + len > mp->m_sb.sb_rextents)
b = mp->m_sb.sb_rextents - len;
}
*seqp = seq + 1;
xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
*pick = b;
return 0;
}
| linux-master | fs/xfs/xfs_rtalloc.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2002 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_quota.h"
#include "xfs_qm.h"
#include "xfs_trace.h"
#include "xfs_error.h"
STATIC void xfs_trans_alloc_dqinfo(xfs_trans_t *);
/*
* Add the locked dquot to the transaction.
* The dquot must be locked, and it cannot be associated with any
* transaction.
*/
void
xfs_trans_dqjoin(
struct xfs_trans *tp,
struct xfs_dquot *dqp)
{
ASSERT(XFS_DQ_IS_LOCKED(dqp));
ASSERT(dqp->q_logitem.qli_dquot == dqp);
/*
* Get a log_item_desc to point at the new item.
*/
xfs_trans_add_item(tp, &dqp->q_logitem.qli_item);
}
/*
* This is called to mark the dquot as needing
* to be logged when the transaction is committed. The dquot must
* already be associated with the given transaction.
* Note that it marks the entire transaction as dirty. In the ordinary
* case, this gets called via xfs_trans_commit, after the transaction
* is already dirty. However, there's nothing stop this from getting
* called directly, as done by xfs_qm_scall_setqlim. Hence, the TRANS_DIRTY
* flag.
*/
void
xfs_trans_log_dquot(
struct xfs_trans *tp,
struct xfs_dquot *dqp)
{
ASSERT(XFS_DQ_IS_LOCKED(dqp));
/* Upgrade the dquot to bigtime format if possible. */
if (dqp->q_id != 0 &&
xfs_has_bigtime(tp->t_mountp) &&
!(dqp->q_type & XFS_DQTYPE_BIGTIME))
dqp->q_type |= XFS_DQTYPE_BIGTIME;
tp->t_flags |= XFS_TRANS_DIRTY;
set_bit(XFS_LI_DIRTY, &dqp->q_logitem.qli_item.li_flags);
}
/*
* Carry forward whatever is left of the quota blk reservation to
* the spanky new transaction
*/
void
xfs_trans_dup_dqinfo(
struct xfs_trans *otp,
struct xfs_trans *ntp)
{
struct xfs_dqtrx *oq, *nq;
int i, j;
struct xfs_dqtrx *oqa, *nqa;
uint64_t blk_res_used;
if (!otp->t_dqinfo)
return;
xfs_trans_alloc_dqinfo(ntp);
for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
oqa = otp->t_dqinfo->dqs[j];
nqa = ntp->t_dqinfo->dqs[j];
for (i = 0; i < XFS_QM_TRANS_MAXDQS; i++) {
blk_res_used = 0;
if (oqa[i].qt_dquot == NULL)
break;
oq = &oqa[i];
nq = &nqa[i];
if (oq->qt_blk_res && oq->qt_bcount_delta > 0)
blk_res_used = oq->qt_bcount_delta;
nq->qt_dquot = oq->qt_dquot;
nq->qt_bcount_delta = nq->qt_icount_delta = 0;
nq->qt_rtbcount_delta = 0;
/*
* Transfer whatever is left of the reservations.
*/
nq->qt_blk_res = oq->qt_blk_res - blk_res_used;
oq->qt_blk_res = blk_res_used;
nq->qt_rtblk_res = oq->qt_rtblk_res -
oq->qt_rtblk_res_used;
oq->qt_rtblk_res = oq->qt_rtblk_res_used;
nq->qt_ino_res = oq->qt_ino_res - oq->qt_ino_res_used;
oq->qt_ino_res = oq->qt_ino_res_used;
}
}
}
/*
* Wrap around mod_dquot to account for both user and group quotas.
*/
void
xfs_trans_mod_dquot_byino(
xfs_trans_t *tp,
xfs_inode_t *ip,
uint field,
int64_t delta)
{
xfs_mount_t *mp = tp->t_mountp;
if (!XFS_IS_QUOTA_ON(mp) ||
xfs_is_quota_inode(&mp->m_sb, ip->i_ino))
return;
if (XFS_IS_UQUOTA_ON(mp) && ip->i_udquot)
(void) xfs_trans_mod_dquot(tp, ip->i_udquot, field, delta);
if (XFS_IS_GQUOTA_ON(mp) && ip->i_gdquot)
(void) xfs_trans_mod_dquot(tp, ip->i_gdquot, field, delta);
if (XFS_IS_PQUOTA_ON(mp) && ip->i_pdquot)
(void) xfs_trans_mod_dquot(tp, ip->i_pdquot, field, delta);
}
STATIC struct xfs_dqtrx *
xfs_trans_get_dqtrx(
struct xfs_trans *tp,
struct xfs_dquot *dqp)
{
int i;
struct xfs_dqtrx *qa;
switch (xfs_dquot_type(dqp)) {
case XFS_DQTYPE_USER:
qa = tp->t_dqinfo->dqs[XFS_QM_TRANS_USR];
break;
case XFS_DQTYPE_GROUP:
qa = tp->t_dqinfo->dqs[XFS_QM_TRANS_GRP];
break;
case XFS_DQTYPE_PROJ:
qa = tp->t_dqinfo->dqs[XFS_QM_TRANS_PRJ];
break;
default:
return NULL;
}
for (i = 0; i < XFS_QM_TRANS_MAXDQS; i++) {
if (qa[i].qt_dquot == NULL ||
qa[i].qt_dquot == dqp)
return &qa[i];
}
return NULL;
}
/*
* Make the changes in the transaction structure.
* The moral equivalent to xfs_trans_mod_sb().
* We don't touch any fields in the dquot, so we don't care
* if it's locked or not (most of the time it won't be).
*/
void
xfs_trans_mod_dquot(
struct xfs_trans *tp,
struct xfs_dquot *dqp,
uint field,
int64_t delta)
{
struct xfs_dqtrx *qtrx;
ASSERT(tp);
ASSERT(XFS_IS_QUOTA_ON(tp->t_mountp));
qtrx = NULL;
if (!delta)
return;
if (tp->t_dqinfo == NULL)
xfs_trans_alloc_dqinfo(tp);
/*
* Find either the first free slot or the slot that belongs
* to this dquot.
*/
qtrx = xfs_trans_get_dqtrx(tp, dqp);
ASSERT(qtrx);
if (qtrx->qt_dquot == NULL)
qtrx->qt_dquot = dqp;
trace_xfs_trans_mod_dquot_before(qtrx);
trace_xfs_trans_mod_dquot(tp, dqp, field, delta);
switch (field) {
/* regular disk blk reservation */
case XFS_TRANS_DQ_RES_BLKS:
qtrx->qt_blk_res += delta;
break;
/* inode reservation */
case XFS_TRANS_DQ_RES_INOS:
qtrx->qt_ino_res += delta;
break;
/* disk blocks used. */
case XFS_TRANS_DQ_BCOUNT:
qtrx->qt_bcount_delta += delta;
break;
case XFS_TRANS_DQ_DELBCOUNT:
qtrx->qt_delbcnt_delta += delta;
break;
/* Inode Count */
case XFS_TRANS_DQ_ICOUNT:
if (qtrx->qt_ino_res && delta > 0) {
qtrx->qt_ino_res_used += delta;
ASSERT(qtrx->qt_ino_res >= qtrx->qt_ino_res_used);
}
qtrx->qt_icount_delta += delta;
break;
/* rtblk reservation */
case XFS_TRANS_DQ_RES_RTBLKS:
qtrx->qt_rtblk_res += delta;
break;
/* rtblk count */
case XFS_TRANS_DQ_RTBCOUNT:
if (qtrx->qt_rtblk_res && delta > 0) {
qtrx->qt_rtblk_res_used += delta;
ASSERT(qtrx->qt_rtblk_res >= qtrx->qt_rtblk_res_used);
}
qtrx->qt_rtbcount_delta += delta;
break;
case XFS_TRANS_DQ_DELRTBCOUNT:
qtrx->qt_delrtb_delta += delta;
break;
default:
ASSERT(0);
}
trace_xfs_trans_mod_dquot_after(qtrx);
}
/*
* Given an array of dqtrx structures, lock all the dquots associated and join
* them to the transaction, provided they have been modified. We know that the
* highest number of dquots of one type - usr, grp and prj - involved in a
* transaction is 3 so we don't need to make this very generic.
*/
STATIC void
xfs_trans_dqlockedjoin(
struct xfs_trans *tp,
struct xfs_dqtrx *q)
{
ASSERT(q[0].qt_dquot != NULL);
if (q[1].qt_dquot == NULL) {
xfs_dqlock(q[0].qt_dquot);
xfs_trans_dqjoin(tp, q[0].qt_dquot);
} else {
ASSERT(XFS_QM_TRANS_MAXDQS == 2);
xfs_dqlock2(q[0].qt_dquot, q[1].qt_dquot);
xfs_trans_dqjoin(tp, q[0].qt_dquot);
xfs_trans_dqjoin(tp, q[1].qt_dquot);
}
}
/* Apply dqtrx changes to the quota reservation counters. */
static inline void
xfs_apply_quota_reservation_deltas(
struct xfs_dquot_res *res,
uint64_t reserved,
int64_t res_used,
int64_t count_delta)
{
if (reserved != 0) {
/*
* Subtle math here: If reserved > res_used (the normal case),
* we're simply subtracting the unused transaction quota
* reservation from the dquot reservation.
*
* If, however, res_used > reserved, then we have allocated
* more quota blocks than were reserved for the transaction.
* We must add that excess to the dquot reservation since it
* tracks (usage + resv) and by definition we didn't reserve
* that excess.
*/
res->reserved -= abs(reserved - res_used);
} else if (count_delta != 0) {
/*
* These blks were never reserved, either inside a transaction
* or outside one (in a delayed allocation). Also, this isn't
* always a negative number since we sometimes deliberately
* skip quota reservations.
*/
res->reserved += count_delta;
}
}
/*
* Called by xfs_trans_commit() and similar in spirit to
* xfs_trans_apply_sb_deltas().
* Go thru all the dquots belonging to this transaction and modify the
* INCORE dquot to reflect the actual usages.
* Unreserve just the reservations done by this transaction.
* dquot is still left locked at exit.
*/
void
xfs_trans_apply_dquot_deltas(
struct xfs_trans *tp)
{
int i, j;
struct xfs_dquot *dqp;
struct xfs_dqtrx *qtrx, *qa;
int64_t totalbdelta;
int64_t totalrtbdelta;
if (!tp->t_dqinfo)
return;
ASSERT(tp->t_dqinfo);
for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
qa = tp->t_dqinfo->dqs[j];
if (qa[0].qt_dquot == NULL)
continue;
/*
* Lock all of the dquots and join them to the transaction.
*/
xfs_trans_dqlockedjoin(tp, qa);
for (i = 0; i < XFS_QM_TRANS_MAXDQS; i++) {
uint64_t blk_res_used;
qtrx = &qa[i];
/*
* The array of dquots is filled
* sequentially, not sparsely.
*/
if ((dqp = qtrx->qt_dquot) == NULL)
break;
ASSERT(XFS_DQ_IS_LOCKED(dqp));
/*
* adjust the actual number of blocks used
*/
/*
* The issue here is - sometimes we don't make a blkquota
* reservation intentionally to be fair to users
* (when the amount is small). On the other hand,
* delayed allocs do make reservations, but that's
* outside of a transaction, so we have no
* idea how much was really reserved.
* So, here we've accumulated delayed allocation blks and
* non-delay blks. The assumption is that the
* delayed ones are always reserved (outside of a
* transaction), and the others may or may not have
* quota reservations.
*/
totalbdelta = qtrx->qt_bcount_delta +
qtrx->qt_delbcnt_delta;
totalrtbdelta = qtrx->qt_rtbcount_delta +
qtrx->qt_delrtb_delta;
if (totalbdelta != 0 || totalrtbdelta != 0 ||
qtrx->qt_icount_delta != 0) {
trace_xfs_trans_apply_dquot_deltas_before(dqp);
trace_xfs_trans_apply_dquot_deltas(qtrx);
}
#ifdef DEBUG
if (totalbdelta < 0)
ASSERT(dqp->q_blk.count >= -totalbdelta);
if (totalrtbdelta < 0)
ASSERT(dqp->q_rtb.count >= -totalrtbdelta);
if (qtrx->qt_icount_delta < 0)
ASSERT(dqp->q_ino.count >= -qtrx->qt_icount_delta);
#endif
if (totalbdelta)
dqp->q_blk.count += totalbdelta;
if (qtrx->qt_icount_delta)
dqp->q_ino.count += qtrx->qt_icount_delta;
if (totalrtbdelta)
dqp->q_rtb.count += totalrtbdelta;
if (totalbdelta != 0 || totalrtbdelta != 0 ||
qtrx->qt_icount_delta != 0)
trace_xfs_trans_apply_dquot_deltas_after(dqp);
/*
* Get any default limits in use.
* Start/reset the timer(s) if needed.
*/
if (dqp->q_id) {
xfs_qm_adjust_dqlimits(dqp);
xfs_qm_adjust_dqtimers(dqp);
}
dqp->q_flags |= XFS_DQFLAG_DIRTY;
/*
* add this to the list of items to get logged
*/
xfs_trans_log_dquot(tp, dqp);
/*
* Take off what's left of the original reservation.
* In case of delayed allocations, there's no
* reservation that a transaction structure knows of.
*/
blk_res_used = max_t(int64_t, 0, qtrx->qt_bcount_delta);
xfs_apply_quota_reservation_deltas(&dqp->q_blk,
qtrx->qt_blk_res, blk_res_used,
qtrx->qt_bcount_delta);
/*
* Adjust the RT reservation.
*/
xfs_apply_quota_reservation_deltas(&dqp->q_rtb,
qtrx->qt_rtblk_res,
qtrx->qt_rtblk_res_used,
qtrx->qt_rtbcount_delta);
/*
* Adjust the inode reservation.
*/
ASSERT(qtrx->qt_ino_res >= qtrx->qt_ino_res_used);
xfs_apply_quota_reservation_deltas(&dqp->q_ino,
qtrx->qt_ino_res,
qtrx->qt_ino_res_used,
qtrx->qt_icount_delta);
ASSERT(dqp->q_blk.reserved >= dqp->q_blk.count);
ASSERT(dqp->q_ino.reserved >= dqp->q_ino.count);
ASSERT(dqp->q_rtb.reserved >= dqp->q_rtb.count);
}
}
}
/*
* Release the reservations, and adjust the dquots accordingly.
* This is called only when the transaction is being aborted. If by
* any chance we have done dquot modifications incore (ie. deltas) already,
* we simply throw those away, since that's the expected behavior
* when a transaction is curtailed without a commit.
*/
void
xfs_trans_unreserve_and_mod_dquots(
struct xfs_trans *tp)
{
int i, j;
struct xfs_dquot *dqp;
struct xfs_dqtrx *qtrx, *qa;
bool locked;
if (!tp->t_dqinfo)
return;
for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
qa = tp->t_dqinfo->dqs[j];
for (i = 0; i < XFS_QM_TRANS_MAXDQS; i++) {
qtrx = &qa[i];
/*
* We assume that the array of dquots is filled
* sequentially, not sparsely.
*/
if ((dqp = qtrx->qt_dquot) == NULL)
break;
/*
* Unreserve the original reservation. We don't care
* about the number of blocks used field, or deltas.
* Also we don't bother to zero the fields.
*/
locked = false;
if (qtrx->qt_blk_res) {
xfs_dqlock(dqp);
locked = true;
dqp->q_blk.reserved -=
(xfs_qcnt_t)qtrx->qt_blk_res;
}
if (qtrx->qt_ino_res) {
if (!locked) {
xfs_dqlock(dqp);
locked = true;
}
dqp->q_ino.reserved -=
(xfs_qcnt_t)qtrx->qt_ino_res;
}
if (qtrx->qt_rtblk_res) {
if (!locked) {
xfs_dqlock(dqp);
locked = true;
}
dqp->q_rtb.reserved -=
(xfs_qcnt_t)qtrx->qt_rtblk_res;
}
if (locked)
xfs_dqunlock(dqp);
}
}
}
STATIC void
xfs_quota_warn(
struct xfs_mount *mp,
struct xfs_dquot *dqp,
int type)
{
enum quota_type qtype;
switch (xfs_dquot_type(dqp)) {
case XFS_DQTYPE_PROJ:
qtype = PRJQUOTA;
break;
case XFS_DQTYPE_USER:
qtype = USRQUOTA;
break;
case XFS_DQTYPE_GROUP:
qtype = GRPQUOTA;
break;
default:
return;
}
quota_send_warning(make_kqid(&init_user_ns, qtype, dqp->q_id),
mp->m_super->s_dev, type);
}
/*
* Decide if we can make an additional reservation against a quota resource.
* Returns an inode QUOTA_NL_ warning code and whether or not it's fatal.
*
* Note that we assume that the numeric difference between the inode and block
* warning codes will always be 3 since it's userspace ABI now, and will never
* decrease the quota reservation, so the *BELOW messages are irrelevant.
*/
static inline int
xfs_dqresv_check(
struct xfs_dquot_res *res,
struct xfs_quota_limits *qlim,
int64_t delta,
bool *fatal)
{
xfs_qcnt_t hardlimit = res->hardlimit;
xfs_qcnt_t softlimit = res->softlimit;
xfs_qcnt_t total_count = res->reserved + delta;
BUILD_BUG_ON(QUOTA_NL_BHARDWARN != QUOTA_NL_IHARDWARN + 3);
BUILD_BUG_ON(QUOTA_NL_BSOFTLONGWARN != QUOTA_NL_ISOFTLONGWARN + 3);
BUILD_BUG_ON(QUOTA_NL_BSOFTWARN != QUOTA_NL_ISOFTWARN + 3);
*fatal = false;
if (delta <= 0)
return QUOTA_NL_NOWARN;
if (!hardlimit)
hardlimit = qlim->hard;
if (!softlimit)
softlimit = qlim->soft;
if (hardlimit && total_count > hardlimit) {
*fatal = true;
return QUOTA_NL_IHARDWARN;
}
if (softlimit && total_count > softlimit) {
time64_t now = ktime_get_real_seconds();
if (res->timer != 0 && now > res->timer) {
*fatal = true;
return QUOTA_NL_ISOFTLONGWARN;
}
return QUOTA_NL_ISOFTWARN;
}
return QUOTA_NL_NOWARN;
}
/*
* This reserves disk blocks and inodes against a dquot.
* Flags indicate if the dquot is to be locked here and also
* if the blk reservation is for RT or regular blocks.
* Sending in XFS_QMOPT_FORCE_RES flag skips the quota check.
*/
STATIC int
xfs_trans_dqresv(
struct xfs_trans *tp,
struct xfs_mount *mp,
struct xfs_dquot *dqp,
int64_t nblks,
long ninos,
uint flags)
{
struct xfs_quotainfo *q = mp->m_quotainfo;
struct xfs_def_quota *defq;
struct xfs_dquot_res *blkres;
struct xfs_quota_limits *qlim;
xfs_dqlock(dqp);
defq = xfs_get_defquota(q, xfs_dquot_type(dqp));
if (flags & XFS_TRANS_DQ_RES_BLKS) {
blkres = &dqp->q_blk;
qlim = &defq->blk;
} else {
blkres = &dqp->q_rtb;
qlim = &defq->rtb;
}
if ((flags & XFS_QMOPT_FORCE_RES) == 0 && dqp->q_id &&
xfs_dquot_is_enforced(dqp)) {
int quota_nl;
bool fatal;
/*
* dquot is locked already. See if we'd go over the hardlimit
* or exceed the timelimit if we'd reserve resources.
*/
quota_nl = xfs_dqresv_check(blkres, qlim, nblks, &fatal);
if (quota_nl != QUOTA_NL_NOWARN) {
/*
* Quota block warning codes are 3 more than the inode
* codes, which we check above.
*/
xfs_quota_warn(mp, dqp, quota_nl + 3);
if (fatal)
goto error_return;
}
quota_nl = xfs_dqresv_check(&dqp->q_ino, &defq->ino, ninos,
&fatal);
if (quota_nl != QUOTA_NL_NOWARN) {
xfs_quota_warn(mp, dqp, quota_nl);
if (fatal)
goto error_return;
}
}
/*
* Change the reservation, but not the actual usage.
* Note that q_blk.reserved = q_blk.count + resv
*/
blkres->reserved += (xfs_qcnt_t)nblks;
dqp->q_ino.reserved += (xfs_qcnt_t)ninos;
/*
* note the reservation amt in the trans struct too,
* so that the transaction knows how much was reserved by
* it against this particular dquot.
* We don't do this when we are reserving for a delayed allocation,
* because we don't have the luxury of a transaction envelope then.
*/
if (tp) {
ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
xfs_trans_mod_dquot(tp, dqp, flags & XFS_QMOPT_RESBLK_MASK,
nblks);
xfs_trans_mod_dquot(tp, dqp, XFS_TRANS_DQ_RES_INOS, ninos);
}
if (XFS_IS_CORRUPT(mp, dqp->q_blk.reserved < dqp->q_blk.count) ||
XFS_IS_CORRUPT(mp, dqp->q_rtb.reserved < dqp->q_rtb.count) ||
XFS_IS_CORRUPT(mp, dqp->q_ino.reserved < dqp->q_ino.count))
goto error_corrupt;
xfs_dqunlock(dqp);
return 0;
error_return:
xfs_dqunlock(dqp);
if (xfs_dquot_type(dqp) == XFS_DQTYPE_PROJ)
return -ENOSPC;
return -EDQUOT;
error_corrupt:
xfs_dqunlock(dqp);
xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
return -EFSCORRUPTED;
}
/*
* Given dquot(s), make disk block and/or inode reservations against them.
* The fact that this does the reservation against user, group and
* project quotas is important, because this follows a all-or-nothing
* approach.
*
* flags = XFS_QMOPT_FORCE_RES evades limit enforcement. Used by chown.
* XFS_QMOPT_ENOSPC returns ENOSPC not EDQUOT. Used by pquota.
* XFS_TRANS_DQ_RES_BLKS reserves regular disk blocks
* XFS_TRANS_DQ_RES_RTBLKS reserves realtime disk blocks
* dquots are unlocked on return, if they were not locked by caller.
*/
int
xfs_trans_reserve_quota_bydquots(
struct xfs_trans *tp,
struct xfs_mount *mp,
struct xfs_dquot *udqp,
struct xfs_dquot *gdqp,
struct xfs_dquot *pdqp,
int64_t nblks,
long ninos,
uint flags)
{
int error;
if (!XFS_IS_QUOTA_ON(mp))
return 0;
ASSERT(flags & XFS_QMOPT_RESBLK_MASK);
if (udqp) {
error = xfs_trans_dqresv(tp, mp, udqp, nblks, ninos, flags);
if (error)
return error;
}
if (gdqp) {
error = xfs_trans_dqresv(tp, mp, gdqp, nblks, ninos, flags);
if (error)
goto unwind_usr;
}
if (pdqp) {
error = xfs_trans_dqresv(tp, mp, pdqp, nblks, ninos, flags);
if (error)
goto unwind_grp;
}
/*
* Didn't change anything critical, so, no need to log
*/
return 0;
unwind_grp:
flags |= XFS_QMOPT_FORCE_RES;
if (gdqp)
xfs_trans_dqresv(tp, mp, gdqp, -nblks, -ninos, flags);
unwind_usr:
flags |= XFS_QMOPT_FORCE_RES;
if (udqp)
xfs_trans_dqresv(tp, mp, udqp, -nblks, -ninos, flags);
return error;
}
/*
* Lock the dquot and change the reservation if we can.
* This doesn't change the actual usage, just the reservation.
* The inode sent in is locked.
*/
int
xfs_trans_reserve_quota_nblks(
struct xfs_trans *tp,
struct xfs_inode *ip,
int64_t dblocks,
int64_t rblocks,
bool force)
{
struct xfs_mount *mp = ip->i_mount;
unsigned int qflags = 0;
int error;
if (!XFS_IS_QUOTA_ON(mp))
return 0;
ASSERT(!xfs_is_quota_inode(&mp->m_sb, ip->i_ino));
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
if (force)
qflags |= XFS_QMOPT_FORCE_RES;
/* Reserve data device quota against the inode's dquots. */
error = xfs_trans_reserve_quota_bydquots(tp, mp, ip->i_udquot,
ip->i_gdquot, ip->i_pdquot, dblocks, 0,
XFS_QMOPT_RES_REGBLKS | qflags);
if (error)
return error;
/* Do the same but for realtime blocks. */
error = xfs_trans_reserve_quota_bydquots(tp, mp, ip->i_udquot,
ip->i_gdquot, ip->i_pdquot, rblocks, 0,
XFS_QMOPT_RES_RTBLKS | qflags);
if (error) {
xfs_trans_reserve_quota_bydquots(tp, mp, ip->i_udquot,
ip->i_gdquot, ip->i_pdquot, -dblocks, 0,
XFS_QMOPT_RES_REGBLKS);
return error;
}
return 0;
}
/* Change the quota reservations for an inode creation activity. */
int
xfs_trans_reserve_quota_icreate(
struct xfs_trans *tp,
struct xfs_dquot *udqp,
struct xfs_dquot *gdqp,
struct xfs_dquot *pdqp,
int64_t dblocks)
{
struct xfs_mount *mp = tp->t_mountp;
if (!XFS_IS_QUOTA_ON(mp))
return 0;
return xfs_trans_reserve_quota_bydquots(tp, mp, udqp, gdqp, pdqp,
dblocks, 1, XFS_QMOPT_RES_REGBLKS);
}
STATIC void
xfs_trans_alloc_dqinfo(
xfs_trans_t *tp)
{
tp->t_dqinfo = kmem_cache_zalloc(xfs_dqtrx_cache,
GFP_KERNEL | __GFP_NOFAIL);
}
void
xfs_trans_free_dqinfo(
xfs_trans_t *tp)
{
if (!tp->t_dqinfo)
return;
kmem_cache_free(xfs_dqtrx_cache, tp->t_dqinfo);
tp->t_dqinfo = NULL;
}
| linux-master | fs/xfs/xfs_trans_dquot.c |
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2016 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_btree.h"
#include "xfs_refcount_btree.h"
#include "xfs_refcount.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans_space.h"
#include "xfs_bit.h"
#include "xfs_alloc.h"
#include "xfs_quota.h"
#include "xfs_reflink.h"
#include "xfs_iomap.h"
#include "xfs_ag.h"
#include "xfs_ag_resv.h"
/*
* Copy on Write of Shared Blocks
*
* XFS must preserve "the usual" file semantics even when two files share
* the same physical blocks. This means that a write to one file must not
* alter the blocks in a different file; the way that we'll do that is
* through the use of a copy-on-write mechanism. At a high level, that
* means that when we want to write to a shared block, we allocate a new
* block, write the data to the new block, and if that succeeds we map the
* new block into the file.
*
* XFS provides a "delayed allocation" mechanism that defers the allocation
* of disk blocks to dirty-but-not-yet-mapped file blocks as long as
* possible. This reduces fragmentation by enabling the filesystem to ask
* for bigger chunks less often, which is exactly what we want for CoW.
*
* The delalloc mechanism begins when the kernel wants to make a block
* writable (write_begin or page_mkwrite). If the offset is not mapped, we
* create a delalloc mapping, which is a regular in-core extent, but without
* a real startblock. (For delalloc mappings, the startblock encodes both
* a flag that this is a delalloc mapping, and a worst-case estimate of how
* many blocks might be required to put the mapping into the BMBT.) delalloc
* mappings are a reservation against the free space in the filesystem;
* adjacent mappings can also be combined into fewer larger mappings.
*
* As an optimization, the CoW extent size hint (cowextsz) creates
* outsized aligned delalloc reservations in the hope of landing out of
* order nearby CoW writes in a single extent on disk, thereby reducing
* fragmentation and improving future performance.
*
* D: --RRRRRRSSSRRRRRRRR--- (data fork)
* C: ------DDDDDDD--------- (CoW fork)
*
* When dirty pages are being written out (typically in writepage), the
* delalloc reservations are converted into unwritten mappings by
* allocating blocks and replacing the delalloc mapping with real ones.
* A delalloc mapping can be replaced by several unwritten ones if the
* free space is fragmented.
*
* D: --RRRRRRSSSRRRRRRRR---
* C: ------UUUUUUU---------
*
* We want to adapt the delalloc mechanism for copy-on-write, since the
* write paths are similar. The first two steps (creating the reservation
* and allocating the blocks) are exactly the same as delalloc except that
* the mappings must be stored in a separate CoW fork because we do not want
* to disturb the mapping in the data fork until we're sure that the write
* succeeded. IO completion in this case is the process of removing the old
* mapping from the data fork and moving the new mapping from the CoW fork to
* the data fork. This will be discussed shortly.
*
* For now, unaligned directio writes will be bounced back to the page cache.
* Block-aligned directio writes will use the same mechanism as buffered
* writes.
*
* Just prior to submitting the actual disk write requests, we convert
* the extents representing the range of the file actually being written
* (as opposed to extra pieces created for the cowextsize hint) to real
* extents. This will become important in the next step:
*
* D: --RRRRRRSSSRRRRRRRR---
* C: ------UUrrUUU---------
*
* CoW remapping must be done after the data block write completes,
* because we don't want to destroy the old data fork map until we're sure
* the new block has been written. Since the new mappings are kept in a
* separate fork, we can simply iterate these mappings to find the ones
* that cover the file blocks that we just CoW'd. For each extent, simply
* unmap the corresponding range in the data fork, map the new range into
* the data fork, and remove the extent from the CoW fork. Because of
* the presence of the cowextsize hint, however, we must be careful
* only to remap the blocks that we've actually written out -- we must
* never remap delalloc reservations nor CoW staging blocks that have
* yet to be written. This corresponds exactly to the real extents in
* the CoW fork:
*
* D: --RRRRRRrrSRRRRRRRR---
* C: ------UU--UUU---------
*
* Since the remapping operation can be applied to an arbitrary file
* range, we record the need for the remap step as a flag in the ioend
* instead of declaring a new IO type. This is required for direct io
* because we only have ioend for the whole dio, and we have to be able to
* remember the presence of unwritten blocks and CoW blocks with a single
* ioend structure. Better yet, the more ground we can cover with one
* ioend, the better.
*/
/*
* Given an AG extent, find the lowest-numbered run of shared blocks
* within that range and return the range in fbno/flen. If
* find_end_of_shared is true, return the longest contiguous extent of
* shared blocks. If there are no shared extents, fbno and flen will
* be set to NULLAGBLOCK and 0, respectively.
*/
static int
xfs_reflink_find_shared(
struct xfs_perag *pag,
struct xfs_trans *tp,
xfs_agblock_t agbno,
xfs_extlen_t aglen,
xfs_agblock_t *fbno,
xfs_extlen_t *flen,
bool find_end_of_shared)
{
struct xfs_buf *agbp;
struct xfs_btree_cur *cur;
int error;
error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
if (error)
return error;
cur = xfs_refcountbt_init_cursor(pag->pag_mount, tp, agbp, pag);
error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen,
find_end_of_shared);
xfs_btree_del_cursor(cur, error);
xfs_trans_brelse(tp, agbp);
return error;
}
/*
* Trim the mapping to the next block where there's a change in the
* shared/unshared status. More specifically, this means that we
* find the lowest-numbered extent of shared blocks that coincides with
* the given block mapping. If the shared extent overlaps the start of
* the mapping, trim the mapping to the end of the shared extent. If
* the shared region intersects the mapping, trim the mapping to the
* start of the shared extent. If there are no shared regions that
* overlap, just return the original extent.
*/
int
xfs_reflink_trim_around_shared(
struct xfs_inode *ip,
struct xfs_bmbt_irec *irec,
bool *shared)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
xfs_agblock_t agbno;
xfs_extlen_t aglen;
xfs_agblock_t fbno;
xfs_extlen_t flen;
int error = 0;
/* Holes, unwritten, and delalloc extents cannot be shared */
if (!xfs_is_cow_inode(ip) || !xfs_bmap_is_written_extent(irec)) {
*shared = false;
return 0;
}
trace_xfs_reflink_trim_around_shared(ip, irec);
pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, irec->br_startblock));
agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock);
aglen = irec->br_blockcount;
error = xfs_reflink_find_shared(pag, NULL, agbno, aglen, &fbno, &flen,
true);
xfs_perag_put(pag);
if (error)
return error;
*shared = false;
if (fbno == NULLAGBLOCK) {
/* No shared blocks at all. */
return 0;
}
if (fbno == agbno) {
/*
* The start of this extent is shared. Truncate the
* mapping at the end of the shared region so that a
* subsequent iteration starts at the start of the
* unshared region.
*/
irec->br_blockcount = flen;
*shared = true;
return 0;
}
/*
* There's a shared extent midway through this extent.
* Truncate the mapping at the start of the shared
* extent so that a subsequent iteration starts at the
* start of the shared region.
*/
irec->br_blockcount = fbno - agbno;
return 0;
}
int
xfs_bmap_trim_cow(
struct xfs_inode *ip,
struct xfs_bmbt_irec *imap,
bool *shared)
{
/* We can't update any real extents in always COW mode. */
if (xfs_is_always_cow_inode(ip) &&
!isnullstartblock(imap->br_startblock)) {
*shared = true;
return 0;
}
/* Trim the mapping to the nearest shared extent boundary. */
return xfs_reflink_trim_around_shared(ip, imap, shared);
}
static int
xfs_reflink_convert_cow_locked(
struct xfs_inode *ip,
xfs_fileoff_t offset_fsb,
xfs_filblks_t count_fsb)
{
struct xfs_iext_cursor icur;
struct xfs_bmbt_irec got;
struct xfs_btree_cur *dummy_cur = NULL;
int dummy_logflags;
int error = 0;
if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &got))
return 0;
do {
if (got.br_startoff >= offset_fsb + count_fsb)
break;
if (got.br_state == XFS_EXT_NORM)
continue;
if (WARN_ON_ONCE(isnullstartblock(got.br_startblock)))
return -EIO;
xfs_trim_extent(&got, offset_fsb, count_fsb);
if (!got.br_blockcount)
continue;
got.br_state = XFS_EXT_NORM;
error = xfs_bmap_add_extent_unwritten_real(NULL, ip,
XFS_COW_FORK, &icur, &dummy_cur, &got,
&dummy_logflags);
if (error)
return error;
} while (xfs_iext_next_extent(ip->i_cowfp, &icur, &got));
return error;
}
/* Convert all of the unwritten CoW extents in a file's range to real ones. */
int
xfs_reflink_convert_cow(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t count)
{
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
xfs_filblks_t count_fsb = end_fsb - offset_fsb;
int error;
ASSERT(count != 0);
xfs_ilock(ip, XFS_ILOCK_EXCL);
error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
/*
* Find the extent that maps the given range in the COW fork. Even if the extent
* is not shared we might have a preallocation for it in the COW fork. If so we
* use it that rather than trigger a new allocation.
*/
static int
xfs_find_trim_cow_extent(
struct xfs_inode *ip,
struct xfs_bmbt_irec *imap,
struct xfs_bmbt_irec *cmap,
bool *shared,
bool *found)
{
xfs_fileoff_t offset_fsb = imap->br_startoff;
xfs_filblks_t count_fsb = imap->br_blockcount;
struct xfs_iext_cursor icur;
*found = false;
/*
* If we don't find an overlapping extent, trim the range we need to
* allocate to fit the hole we found.
*/
if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, cmap))
cmap->br_startoff = offset_fsb + count_fsb;
if (cmap->br_startoff > offset_fsb) {
xfs_trim_extent(imap, imap->br_startoff,
cmap->br_startoff - imap->br_startoff);
return xfs_bmap_trim_cow(ip, imap, shared);
}
*shared = true;
if (isnullstartblock(cmap->br_startblock)) {
xfs_trim_extent(imap, cmap->br_startoff, cmap->br_blockcount);
return 0;
}
/* real extent found - no need to allocate */
xfs_trim_extent(cmap, offset_fsb, count_fsb);
*found = true;
return 0;
}
static int
xfs_reflink_convert_unwritten(
struct xfs_inode *ip,
struct xfs_bmbt_irec *imap,
struct xfs_bmbt_irec *cmap,
bool convert_now)
{
xfs_fileoff_t offset_fsb = imap->br_startoff;
xfs_filblks_t count_fsb = imap->br_blockcount;
int error;
/*
* cmap might larger than imap due to cowextsize hint.
*/
xfs_trim_extent(cmap, offset_fsb, count_fsb);
/*
* COW fork extents are supposed to remain unwritten until we're ready
* to initiate a disk write. For direct I/O we are going to write the
* data and need the conversion, but for buffered writes we're done.
*/
if (!convert_now || cmap->br_state == XFS_EXT_NORM)
return 0;
trace_xfs_reflink_convert_cow(ip, cmap);
error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb);
if (!error)
cmap->br_state = XFS_EXT_NORM;
return error;
}
static int
xfs_reflink_fill_cow_hole(
struct xfs_inode *ip,
struct xfs_bmbt_irec *imap,
struct xfs_bmbt_irec *cmap,
bool *shared,
uint *lockmode,
bool convert_now)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
xfs_filblks_t resaligned;
xfs_extlen_t resblks;
int nimaps;
int error;
bool found;
resaligned = xfs_aligned_fsb_count(imap->br_startoff,
imap->br_blockcount, xfs_get_cowextsz_hint(ip));
resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
xfs_iunlock(ip, *lockmode);
*lockmode = 0;
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
false, &tp);
if (error)
return error;
*lockmode = XFS_ILOCK_EXCL;
error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found);
if (error || !*shared)
goto out_trans_cancel;
if (found) {
xfs_trans_cancel(tp);
goto convert;
}
/* Allocate the entire reservation as unwritten blocks. */
nimaps = 1;
error = xfs_bmapi_write(tp, ip, imap->br_startoff, imap->br_blockcount,
XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0, cmap,
&nimaps);
if (error)
goto out_trans_cancel;
xfs_inode_set_cowblocks_tag(ip);
error = xfs_trans_commit(tp);
if (error)
return error;
/*
* Allocation succeeded but the requested range was not even partially
* satisfied? Bail out!
*/
if (nimaps == 0)
return -ENOSPC;
convert:
return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now);
out_trans_cancel:
xfs_trans_cancel(tp);
return error;
}
static int
xfs_reflink_fill_delalloc(
struct xfs_inode *ip,
struct xfs_bmbt_irec *imap,
struct xfs_bmbt_irec *cmap,
bool *shared,
uint *lockmode,
bool convert_now)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int nimaps;
int error;
bool found;
do {
xfs_iunlock(ip, *lockmode);
*lockmode = 0;
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, 0, 0,
false, &tp);
if (error)
return error;
*lockmode = XFS_ILOCK_EXCL;
error = xfs_find_trim_cow_extent(ip, imap, cmap, shared,
&found);
if (error || !*shared)
goto out_trans_cancel;
if (found) {
xfs_trans_cancel(tp);
break;
}
ASSERT(isnullstartblock(cmap->br_startblock) ||
cmap->br_startblock == DELAYSTARTBLOCK);
/*
* Replace delalloc reservation with an unwritten extent.
*/
nimaps = 1;
error = xfs_bmapi_write(tp, ip, cmap->br_startoff,
cmap->br_blockcount,
XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0,
cmap, &nimaps);
if (error)
goto out_trans_cancel;
xfs_inode_set_cowblocks_tag(ip);
error = xfs_trans_commit(tp);
if (error)
return error;
/*
* Allocation succeeded but the requested range was not even
* partially satisfied? Bail out!
*/
if (nimaps == 0)
return -ENOSPC;
} while (cmap->br_startoff + cmap->br_blockcount <= imap->br_startoff);
return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now);
out_trans_cancel:
xfs_trans_cancel(tp);
return error;
}
/* Allocate all CoW reservations covering a range of blocks in a file. */
int
xfs_reflink_allocate_cow(
struct xfs_inode *ip,
struct xfs_bmbt_irec *imap,
struct xfs_bmbt_irec *cmap,
bool *shared,
uint *lockmode,
bool convert_now)
{
int error;
bool found;
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
if (!ip->i_cowfp) {
ASSERT(!xfs_is_reflink_inode(ip));
xfs_ifork_init_cow(ip);
}
error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found);
if (error || !*shared)
return error;
/* CoW fork has a real extent */
if (found)
return xfs_reflink_convert_unwritten(ip, imap, cmap,
convert_now);
/*
* CoW fork does not have an extent and data extent is shared.
* Allocate a real extent in the CoW fork.
*/
if (cmap->br_startoff > imap->br_startoff)
return xfs_reflink_fill_cow_hole(ip, imap, cmap, shared,
lockmode, convert_now);
/*
* CoW fork has a delalloc reservation. Replace it with a real extent.
* There may or may not be a data fork mapping.
*/
if (isnullstartblock(cmap->br_startblock) ||
cmap->br_startblock == DELAYSTARTBLOCK)
return xfs_reflink_fill_delalloc(ip, imap, cmap, shared,
lockmode, convert_now);
/* Shouldn't get here. */
ASSERT(0);
return -EFSCORRUPTED;
}
/*
* Cancel CoW reservations for some block range of an inode.
*
* If cancel_real is true this function cancels all COW fork extents for the
* inode; if cancel_real is false, real extents are not cleared.
*
* Caller must have already joined the inode to the current transaction. The
* inode will be joined to the transaction returned to the caller.
*/
int
xfs_reflink_cancel_cow_blocks(
struct xfs_inode *ip,
struct xfs_trans **tpp,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t end_fsb,
bool cancel_real)
{
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
struct xfs_bmbt_irec got, del;
struct xfs_iext_cursor icur;
int error = 0;
if (!xfs_inode_has_cow_data(ip))
return 0;
if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))
return 0;
/* Walk backwards until we're out of the I/O range... */
while (got.br_startoff + got.br_blockcount > offset_fsb) {
del = got;
xfs_trim_extent(&del, offset_fsb, end_fsb - offset_fsb);
/* Extent delete may have bumped ext forward */
if (!del.br_blockcount) {
xfs_iext_prev(ifp, &icur);
goto next_extent;
}
trace_xfs_reflink_cancel_cow(ip, &del);
if (isnullstartblock(del.br_startblock)) {
error = xfs_bmap_del_extent_delay(ip, XFS_COW_FORK,
&icur, &got, &del);
if (error)
break;
} else if (del.br_state == XFS_EXT_UNWRITTEN || cancel_real) {
ASSERT((*tpp)->t_highest_agno == NULLAGNUMBER);
/* Free the CoW orphan record. */
xfs_refcount_free_cow_extent(*tpp, del.br_startblock,
del.br_blockcount);
error = xfs_free_extent_later(*tpp, del.br_startblock,
del.br_blockcount, NULL,
XFS_AG_RESV_NONE);
if (error)
break;
/* Roll the transaction */
error = xfs_defer_finish(tpp);
if (error)
break;
/* Remove the mapping from the CoW fork. */
xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
/* Remove the quota reservation */
error = xfs_quota_unreserve_blkres(ip,
del.br_blockcount);
if (error)
break;
} else {
/* Didn't do anything, push cursor back. */
xfs_iext_prev(ifp, &icur);
}
next_extent:
if (!xfs_iext_get_extent(ifp, &icur, &got))
break;
}
/* clear tag if cow fork is emptied */
if (!ifp->if_bytes)
xfs_inode_clear_cowblocks_tag(ip);
return error;
}
/*
* Cancel CoW reservations for some byte range of an inode.
*
* If cancel_real is true this function cancels all COW fork extents for the
* inode; if cancel_real is false, real extents are not cleared.
*/
int
xfs_reflink_cancel_cow_range(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t count,
bool cancel_real)
{
struct xfs_trans *tp;
xfs_fileoff_t offset_fsb;
xfs_fileoff_t end_fsb;
int error;
trace_xfs_reflink_cancel_cow_range(ip, offset, count);
ASSERT(ip->i_cowfp);
offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
if (count == NULLFILEOFF)
end_fsb = NULLFILEOFF;
else
end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
/* Start a rolling transaction to remove the mappings */
error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
0, 0, 0, &tp);
if (error)
goto out;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
/* Scrape out the old CoW reservations */
error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb,
cancel_real);
if (error)
goto out_cancel;
error = xfs_trans_commit(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
out_cancel:
xfs_trans_cancel(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
out:
trace_xfs_reflink_cancel_cow_range_error(ip, error, _RET_IP_);
return error;
}
/*
* Remap part of the CoW fork into the data fork.
*
* We aim to remap the range starting at @offset_fsb and ending at @end_fsb
* into the data fork; this function will remap what it can (at the end of the
* range) and update @end_fsb appropriately. Each remap gets its own
* transaction because we can end up merging and splitting bmbt blocks for
* every remap operation and we'd like to keep the block reservation
* requirements as low as possible.
*/
STATIC int
xfs_reflink_end_cow_extent(
struct xfs_inode *ip,
xfs_fileoff_t *offset_fsb,
xfs_fileoff_t end_fsb)
{
struct xfs_iext_cursor icur;
struct xfs_bmbt_irec got, del, data;
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);
unsigned int resblks;
int nmaps;
int error;
/* No COW extents? That's easy! */
if (ifp->if_bytes == 0) {
*offset_fsb = end_fsb;
return 0;
}
resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
XFS_TRANS_RESERVE, &tp);
if (error)
return error;
/*
* Lock the inode. We have to ijoin without automatic unlock because
* the lead transaction is the refcountbt record deletion; the data
* fork update follows as a deferred log item.
*/
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_REFLINK_END_COW_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip,
XFS_IEXT_REFLINK_END_COW_CNT);
if (error)
goto out_cancel;
/*
* In case of racing, overlapping AIO writes no COW extents might be
* left by the time I/O completes for the loser of the race. In that
* case we are done.
*/
if (!xfs_iext_lookup_extent(ip, ifp, *offset_fsb, &icur, &got) ||
got.br_startoff >= end_fsb) {
*offset_fsb = end_fsb;
goto out_cancel;
}
/*
* Only remap real extents that contain data. With AIO, speculative
* preallocations can leak into the range we are called upon, and we
* need to skip them. Preserve @got for the eventual CoW fork
* deletion; from now on @del represents the mapping that we're
* actually remapping.
*/
while (!xfs_bmap_is_written_extent(&got)) {
if (!xfs_iext_next_extent(ifp, &icur, &got) ||
got.br_startoff >= end_fsb) {
*offset_fsb = end_fsb;
goto out_cancel;
}
}
del = got;
/* Grab the corresponding mapping in the data fork. */
nmaps = 1;
error = xfs_bmapi_read(ip, del.br_startoff, del.br_blockcount, &data,
&nmaps, 0);
if (error)
goto out_cancel;
/* We can only remap the smaller of the two extent sizes. */
data.br_blockcount = min(data.br_blockcount, del.br_blockcount);
del.br_blockcount = data.br_blockcount;
trace_xfs_reflink_cow_remap_from(ip, &del);
trace_xfs_reflink_cow_remap_to(ip, &data);
if (xfs_bmap_is_real_extent(&data)) {
/*
* If the extent we're remapping is backed by storage (written
* or not), unmap the extent and drop its refcount.
*/
xfs_bmap_unmap_extent(tp, ip, &data);
xfs_refcount_decrease_extent(tp, &data);
xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT,
-data.br_blockcount);
} else if (data.br_startblock == DELAYSTARTBLOCK) {
int done;
/*
* If the extent we're remapping is a delalloc reservation,
* we can use the regular bunmapi function to release the
* incore state. Dropping the delalloc reservation takes care
* of the quota reservation for us.
*/
error = xfs_bunmapi(NULL, ip, data.br_startoff,
data.br_blockcount, 0, 1, &done);
if (error)
goto out_cancel;
ASSERT(done);
}
/* Free the CoW orphan record. */
xfs_refcount_free_cow_extent(tp, del.br_startblock, del.br_blockcount);
/* Map the new blocks into the data fork. */
xfs_bmap_map_extent(tp, ip, &del);
/* Charge this new data fork mapping to the on-disk quota. */
xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_DELBCOUNT,
(long)del.br_blockcount);
/* Remove the mapping from the CoW fork. */
xfs_bmap_del_extent_cow(ip, &icur, &got, &del);
error = xfs_trans_commit(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
if (error)
return error;
/* Update the caller about how much progress we made. */
*offset_fsb = del.br_startoff + del.br_blockcount;
return 0;
out_cancel:
xfs_trans_cancel(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
/*
* Remap parts of a file's data fork after a successful CoW.
*/
int
xfs_reflink_end_cow(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t count)
{
xfs_fileoff_t offset_fsb;
xfs_fileoff_t end_fsb;
int error = 0;
trace_xfs_reflink_end_cow(ip, offset, count);
offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
/*
* Walk forwards until we've remapped the I/O range. The loop function
* repeatedly cycles the ILOCK to allocate one transaction per remapped
* extent.
*
* If we're being called by writeback then the pages will still
* have PageWriteback set, which prevents races with reflink remapping
* and truncate. Reflink remapping prevents races with writeback by
* taking the iolock and mmaplock before flushing the pages and
* remapping, which means there won't be any further writeback or page
* cache dirtying until the reflink completes.
*
* We should never have two threads issuing writeback for the same file
* region. There are also have post-eof checks in the writeback
* preparation code so that we don't bother writing out pages that are
* about to be truncated.
*
* If we're being called as part of directio write completion, the dio
* count is still elevated, which reflink and truncate will wait for.
* Reflink remapping takes the iolock and mmaplock and waits for
* pending dio to finish, which should prevent any directio until the
* remap completes. Multiple concurrent directio writes to the same
* region are handled by end_cow processing only occurring for the
* threads which succeed; the outcome of multiple overlapping direct
* writes is not well defined anyway.
*
* It's possible that a buffered write and a direct write could collide
* here (the buffered write stumbles in after the dio flushes and
* invalidates the page cache and immediately queues writeback), but we
* have never supported this 100%. If either disk write succeeds the
* blocks will be remapped.
*/
while (end_fsb > offset_fsb && !error)
error = xfs_reflink_end_cow_extent(ip, &offset_fsb, end_fsb);
if (error)
trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_);
return error;
}
/*
* Free all CoW staging blocks that are still referenced by the ondisk refcount
* metadata. The ondisk metadata does not track which inode created the
* staging extent, so callers must ensure that there are no cached inodes with
* live CoW staging extents.
*/
int
xfs_reflink_recover_cow(
struct xfs_mount *mp)
{
struct xfs_perag *pag;
xfs_agnumber_t agno;
int error = 0;
if (!xfs_has_reflink(mp))
return 0;
for_each_perag(mp, agno, pag) {
error = xfs_refcount_recover_cow_leftovers(mp, pag);
if (error) {
xfs_perag_rele(pag);
break;
}
}
return error;
}
/*
* Reflinking (Block) Ranges of Two Files Together
*
* First, ensure that the reflink flag is set on both inodes. The flag is an
* optimization to avoid unnecessary refcount btree lookups in the write path.
*
* Now we can iteratively remap the range of extents (and holes) in src to the
* corresponding ranges in dest. Let drange and srange denote the ranges of
* logical blocks in dest and src touched by the reflink operation.
*
* While the length of drange is greater than zero,
* - Read src's bmbt at the start of srange ("imap")
* - If imap doesn't exist, make imap appear to start at the end of srange
* with zero length.
* - If imap starts before srange, advance imap to start at srange.
* - If imap goes beyond srange, truncate imap to end at the end of srange.
* - Punch (imap start - srange start + imap len) blocks from dest at
* offset (drange start).
* - If imap points to a real range of pblks,
* > Increase the refcount of the imap's pblks
* > Map imap's pblks into dest at the offset
* (drange start + imap start - srange start)
* - Advance drange and srange by (imap start - srange start + imap len)
*
* Finally, if the reflink made dest longer, update both the in-core and
* on-disk file sizes.
*
* ASCII Art Demonstration:
*
* Let's say we want to reflink this source file:
*
* ----SSSSSSS-SSSSS----SSSSSS (src file)
* <-------------------->
*
* into this destination file:
*
* --DDDDDDDDDDDDDDDDDDD--DDD (dest file)
* <-------------------->
* '-' means a hole, and 'S' and 'D' are written blocks in the src and dest.
* Observe that the range has different logical offsets in either file.
*
* Consider that the first extent in the source file doesn't line up with our
* reflink range. Unmapping and remapping are separate operations, so we can
* unmap more blocks from the destination file than we remap.
*
* ----SSSSSSS-SSSSS----SSSSSS
* <------->
* --DDDDD---------DDDDD--DDD
* <------->
*
* Now remap the source extent into the destination file:
*
* ----SSSSSSS-SSSSS----SSSSSS
* <------->
* --DDDDD--SSSSSSSDDDDD--DDD
* <------->
*
* Do likewise with the second hole and extent in our range. Holes in the
* unmap range don't affect our operation.
*
* ----SSSSSSS-SSSSS----SSSSSS
* <---->
* --DDDDD--SSSSSSS-SSSSS-DDD
* <---->
*
* Finally, unmap and remap part of the third extent. This will increase the
* size of the destination file.
*
* ----SSSSSSS-SSSSS----SSSSSS
* <----->
* --DDDDD--SSSSSSS-SSSSS----SSS
* <----->
*
* Once we update the destination file's i_size, we're done.
*/
/*
* Ensure the reflink bit is set in both inodes.
*/
STATIC int
xfs_reflink_set_inode_flag(
struct xfs_inode *src,
struct xfs_inode *dest)
{
struct xfs_mount *mp = src->i_mount;
int error;
struct xfs_trans *tp;
if (xfs_is_reflink_inode(src) && xfs_is_reflink_inode(dest))
return 0;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
if (error)
goto out_error;
/* Lock both files against IO */
if (src->i_ino == dest->i_ino)
xfs_ilock(src, XFS_ILOCK_EXCL);
else
xfs_lock_two_inodes(src, XFS_ILOCK_EXCL, dest, XFS_ILOCK_EXCL);
if (!xfs_is_reflink_inode(src)) {
trace_xfs_reflink_set_inode_flag(src);
xfs_trans_ijoin(tp, src, XFS_ILOCK_EXCL);
src->i_diflags2 |= XFS_DIFLAG2_REFLINK;
xfs_trans_log_inode(tp, src, XFS_ILOG_CORE);
xfs_ifork_init_cow(src);
} else
xfs_iunlock(src, XFS_ILOCK_EXCL);
if (src->i_ino == dest->i_ino)
goto commit_flags;
if (!xfs_is_reflink_inode(dest)) {
trace_xfs_reflink_set_inode_flag(dest);
xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL);
dest->i_diflags2 |= XFS_DIFLAG2_REFLINK;
xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
xfs_ifork_init_cow(dest);
} else
xfs_iunlock(dest, XFS_ILOCK_EXCL);
commit_flags:
error = xfs_trans_commit(tp);
if (error)
goto out_error;
return error;
out_error:
trace_xfs_reflink_set_inode_flag_error(dest, error, _RET_IP_);
return error;
}
/*
* Update destination inode size & cowextsize hint, if necessary.
*/
int
xfs_reflink_update_dest(
struct xfs_inode *dest,
xfs_off_t newlen,
xfs_extlen_t cowextsize,
unsigned int remap_flags)
{
struct xfs_mount *mp = dest->i_mount;
struct xfs_trans *tp;
int error;
if (newlen <= i_size_read(VFS_I(dest)) && cowextsize == 0)
return 0;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
if (error)
goto out_error;
xfs_ilock(dest, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL);
if (newlen > i_size_read(VFS_I(dest))) {
trace_xfs_reflink_update_inode_size(dest, newlen);
i_size_write(VFS_I(dest), newlen);
dest->i_disk_size = newlen;
}
if (cowextsize) {
dest->i_cowextsize = cowextsize;
dest->i_diflags2 |= XFS_DIFLAG2_COWEXTSIZE;
}
xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
error = xfs_trans_commit(tp);
if (error)
goto out_error;
return error;
out_error:
trace_xfs_reflink_update_inode_size_error(dest, error, _RET_IP_);
return error;
}
/*
* Do we have enough reserve in this AG to handle a reflink? The refcount
* btree already reserved all the space it needs, but the rmap btree can grow
* infinitely, so we won't allow more reflinks when the AG is down to the
* btree reserves.
*/
static int
xfs_reflink_ag_has_free_space(
struct xfs_mount *mp,
xfs_agnumber_t agno)
{
struct xfs_perag *pag;
int error = 0;
if (!xfs_has_rmapbt(mp))
return 0;
pag = xfs_perag_get(mp, agno);
if (xfs_ag_resv_critical(pag, XFS_AG_RESV_RMAPBT) ||
xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA))
error = -ENOSPC;
xfs_perag_put(pag);
return error;
}
/*
* Remap the given extent into the file. The dmap blockcount will be set to
* the number of blocks that were actually remapped.
*/
STATIC int
xfs_reflink_remap_extent(
struct xfs_inode *ip,
struct xfs_bmbt_irec *dmap,
xfs_off_t new_isize)
{
struct xfs_bmbt_irec smap;
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
xfs_off_t newlen;
int64_t qdelta = 0;
unsigned int resblks;
bool quota_reserved = true;
bool smap_real;
bool dmap_written = xfs_bmap_is_written_extent(dmap);
int iext_delta = 0;
int nimaps;
int error;
/*
* Start a rolling transaction to switch the mappings.
*
* Adding a written extent to the extent map can cause a bmbt split,
* and removing a mapped extent from the extent can cause a bmbt split.
* The two operations cannot both cause a split since they operate on
* the same index in the bmap btree, so we only need a reservation for
* one bmbt split if either thing is happening. However, we haven't
* locked the inode yet, so we reserve assuming this is the case.
*
* The first allocation call tries to reserve enough space to handle
* mapping dmap into a sparse part of the file plus the bmbt split. We
* haven't locked the inode or read the existing mapping yet, so we do
* not know for sure that we need the space. This should succeed most
* of the time.
*
* If the first attempt fails, try again but reserving only enough
* space to handle a bmbt split. This is the hard minimum requirement,
* and we revisit quota reservations later when we know more about what
* we're remapping.
*/
resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
resblks + dmap->br_blockcount, 0, false, &tp);
if (error == -EDQUOT || error == -ENOSPC) {
quota_reserved = false;
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
resblks, 0, false, &tp);
}
if (error)
goto out;
/*
* Read what's currently mapped in the destination file into smap.
* If smap isn't a hole, we will have to remove it before we can add
* dmap to the destination file.
*/
nimaps = 1;
error = xfs_bmapi_read(ip, dmap->br_startoff, dmap->br_blockcount,
&smap, &nimaps, 0);
if (error)
goto out_cancel;
ASSERT(nimaps == 1 && smap.br_startoff == dmap->br_startoff);
smap_real = xfs_bmap_is_real_extent(&smap);
/*
* We can only remap as many blocks as the smaller of the two extent
* maps, because we can only remap one extent at a time.
*/
dmap->br_blockcount = min(dmap->br_blockcount, smap.br_blockcount);
ASSERT(dmap->br_blockcount == smap.br_blockcount);
trace_xfs_reflink_remap_extent_dest(ip, &smap);
/*
* Two extents mapped to the same physical block must not have
* different states; that's filesystem corruption. Move on to the next
* extent if they're both holes or both the same physical extent.
*/
if (dmap->br_startblock == smap.br_startblock) {
if (dmap->br_state != smap.br_state)
error = -EFSCORRUPTED;
goto out_cancel;
}
/* If both extents are unwritten, leave them alone. */
if (dmap->br_state == XFS_EXT_UNWRITTEN &&
smap.br_state == XFS_EXT_UNWRITTEN)
goto out_cancel;
/* No reflinking if the AG of the dest mapping is low on space. */
if (dmap_written) {
error = xfs_reflink_ag_has_free_space(mp,
XFS_FSB_TO_AGNO(mp, dmap->br_startblock));
if (error)
goto out_cancel;
}
/*
* Increase quota reservation if we think the quota block counter for
* this file could increase.
*
* If we are mapping a written extent into the file, we need to have
* enough quota block count reservation to handle the blocks in that
* extent. We log only the delta to the quota block counts, so if the
* extent we're unmapping also has blocks allocated to it, we don't
* need a quota reservation for the extent itself.
*
* Note that if we're replacing a delalloc reservation with a written
* extent, we have to take the full quota reservation because removing
* the delalloc reservation gives the block count back to the quota
* count. This is suboptimal, but the VFS flushed the dest range
* before we started. That should have removed all the delalloc
* reservations, but we code defensively.
*
* xfs_trans_alloc_inode above already tried to grab an even larger
* quota reservation, and kicked off a blockgc scan if it couldn't.
* If we can't get a potentially smaller quota reservation now, we're
* done.
*/
if (!quota_reserved && !smap_real && dmap_written) {
error = xfs_trans_reserve_quota_nblks(tp, ip,
dmap->br_blockcount, 0, false);
if (error)
goto out_cancel;
}
if (smap_real)
++iext_delta;
if (dmap_written)
++iext_delta;
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, iext_delta);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip, iext_delta);
if (error)
goto out_cancel;
if (smap_real) {
/*
* If the extent we're unmapping is backed by storage (written
* or not), unmap the extent and drop its refcount.
*/
xfs_bmap_unmap_extent(tp, ip, &smap);
xfs_refcount_decrease_extent(tp, &smap);
qdelta -= smap.br_blockcount;
} else if (smap.br_startblock == DELAYSTARTBLOCK) {
int done;
/*
* If the extent we're unmapping is a delalloc reservation,
* we can use the regular bunmapi function to release the
* incore state. Dropping the delalloc reservation takes care
* of the quota reservation for us.
*/
error = xfs_bunmapi(NULL, ip, smap.br_startoff,
smap.br_blockcount, 0, 1, &done);
if (error)
goto out_cancel;
ASSERT(done);
}
/*
* If the extent we're sharing is backed by written storage, increase
* its refcount and map it into the file.
*/
if (dmap_written) {
xfs_refcount_increase_extent(tp, dmap);
xfs_bmap_map_extent(tp, ip, dmap);
qdelta += dmap->br_blockcount;
}
xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, qdelta);
/* Update dest isize if needed. */
newlen = XFS_FSB_TO_B(mp, dmap->br_startoff + dmap->br_blockcount);
newlen = min_t(xfs_off_t, newlen, new_isize);
if (newlen > i_size_read(VFS_I(ip))) {
trace_xfs_reflink_update_inode_size(ip, newlen);
i_size_write(VFS_I(ip), newlen);
ip->i_disk_size = newlen;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
}
/* Commit everything and unlock. */
error = xfs_trans_commit(tp);
goto out_unlock;
out_cancel:
xfs_trans_cancel(tp);
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
out:
if (error)
trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_);
return error;
}
/* Remap a range of one file to the other. */
int
xfs_reflink_remap_blocks(
struct xfs_inode *src,
loff_t pos_in,
struct xfs_inode *dest,
loff_t pos_out,
loff_t remap_len,
loff_t *remapped)
{
struct xfs_bmbt_irec imap;
struct xfs_mount *mp = src->i_mount;
xfs_fileoff_t srcoff = XFS_B_TO_FSBT(mp, pos_in);
xfs_fileoff_t destoff = XFS_B_TO_FSBT(mp, pos_out);
xfs_filblks_t len;
xfs_filblks_t remapped_len = 0;
xfs_off_t new_isize = pos_out + remap_len;
int nimaps;
int error = 0;
len = min_t(xfs_filblks_t, XFS_B_TO_FSB(mp, remap_len),
XFS_MAX_FILEOFF);
trace_xfs_reflink_remap_blocks(src, srcoff, len, dest, destoff);
while (len > 0) {
unsigned int lock_mode;
/* Read extent from the source file */
nimaps = 1;
lock_mode = xfs_ilock_data_map_shared(src);
error = xfs_bmapi_read(src, srcoff, len, &imap, &nimaps, 0);
xfs_iunlock(src, lock_mode);
if (error)
break;
/*
* The caller supposedly flushed all dirty pages in the source
* file range, which means that writeback should have allocated
* or deleted all delalloc reservations in that range. If we
* find one, that's a good sign that something is seriously
* wrong here.
*/
ASSERT(nimaps == 1 && imap.br_startoff == srcoff);
if (imap.br_startblock == DELAYSTARTBLOCK) {
ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
error = -EFSCORRUPTED;
break;
}
trace_xfs_reflink_remap_extent_src(src, &imap);
/* Remap into the destination file at the given offset. */
imap.br_startoff = destoff;
error = xfs_reflink_remap_extent(dest, &imap, new_isize);
if (error)
break;
if (fatal_signal_pending(current)) {
error = -EINTR;
break;
}
/* Advance drange/srange */
srcoff += imap.br_blockcount;
destoff += imap.br_blockcount;
len -= imap.br_blockcount;
remapped_len += imap.br_blockcount;
}
if (error)
trace_xfs_reflink_remap_blocks_error(dest, error, _RET_IP_);
*remapped = min_t(loff_t, remap_len,
XFS_FSB_TO_B(src->i_mount, remapped_len));
return error;
}
/*
* If we're reflinking to a point past the destination file's EOF, we must
* zero any speculative post-EOF preallocations that sit between the old EOF
* and the destination file offset.
*/
static int
xfs_reflink_zero_posteof(
struct xfs_inode *ip,
loff_t pos)
{
loff_t isize = i_size_read(VFS_I(ip));
if (pos <= isize)
return 0;
trace_xfs_zero_eof(ip, isize, pos - isize);
return xfs_zero_range(ip, isize, pos - isize, NULL);
}
/*
* Prepare two files for range cloning. Upon a successful return both inodes
* will have the iolock and mmaplock held, the page cache of the out file will
* be truncated, and any leases on the out file will have been broken. This
* function borrows heavily from xfs_file_aio_write_checks.
*
* The VFS allows partial EOF blocks to "match" for dedupe even though it hasn't
* checked that the bytes beyond EOF physically match. Hence we cannot use the
* EOF block in the source dedupe range because it's not a complete block match,
* hence can introduce a corruption into the file that has it's block replaced.
*
* In similar fashion, the VFS file cloning also allows partial EOF blocks to be
* "block aligned" for the purposes of cloning entire files. However, if the
* source file range includes the EOF block and it lands within the existing EOF
* of the destination file, then we can expose stale data from beyond the source
* file EOF in the destination file.
*
* XFS doesn't support partial block sharing, so in both cases we have check
* these cases ourselves. For dedupe, we can simply round the length to dedupe
* down to the previous whole block and ignore the partial EOF block. While this
* means we can't dedupe the last block of a file, this is an acceptible
* tradeoff for simplicity on implementation.
*
* For cloning, we want to share the partial EOF block if it is also the new EOF
* block of the destination file. If the partial EOF block lies inside the
* existing destination EOF, then we have to abort the clone to avoid exposing
* stale data in the destination file. Hence we reject these clone attempts with
* -EINVAL in this case.
*/
int
xfs_reflink_remap_prep(
struct file *file_in,
loff_t pos_in,
struct file *file_out,
loff_t pos_out,
loff_t *len,
unsigned int remap_flags)
{
struct inode *inode_in = file_inode(file_in);
struct xfs_inode *src = XFS_I(inode_in);
struct inode *inode_out = file_inode(file_out);
struct xfs_inode *dest = XFS_I(inode_out);
int ret;
/* Lock both files against IO */
ret = xfs_ilock2_io_mmap(src, dest);
if (ret)
return ret;
/* Check file eligibility and prepare for block sharing. */
ret = -EINVAL;
/* Don't reflink realtime inodes */
if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
goto out_unlock;
/* Don't share DAX file data with non-DAX file. */
if (IS_DAX(inode_in) != IS_DAX(inode_out))
goto out_unlock;
if (!IS_DAX(inode_in))
ret = generic_remap_file_range_prep(file_in, pos_in, file_out,
pos_out, len, remap_flags);
else
ret = dax_remap_file_range_prep(file_in, pos_in, file_out,
pos_out, len, remap_flags, &xfs_read_iomap_ops);
if (ret || *len == 0)
goto out_unlock;
/* Attach dquots to dest inode before changing block map */
ret = xfs_qm_dqattach(dest);
if (ret)
goto out_unlock;
/*
* Zero existing post-eof speculative preallocations in the destination
* file.
*/
ret = xfs_reflink_zero_posteof(dest, pos_out);
if (ret)
goto out_unlock;
/* Set flags and remap blocks. */
ret = xfs_reflink_set_inode_flag(src, dest);
if (ret)
goto out_unlock;
/*
* If pos_out > EOF, we may have dirtied blocks between EOF and
* pos_out. In that case, we need to extend the flush and unmap to cover
* from EOF to the end of the copy length.
*/
if (pos_out > XFS_ISIZE(dest)) {
loff_t flen = *len + (pos_out - XFS_ISIZE(dest));
ret = xfs_flush_unmap_range(dest, XFS_ISIZE(dest), flen);
} else {
ret = xfs_flush_unmap_range(dest, pos_out, *len);
}
if (ret)
goto out_unlock;
return 0;
out_unlock:
xfs_iunlock2_io_mmap(src, dest);
return ret;
}
/* Does this inode need the reflink flag? */
int
xfs_reflink_inode_has_shared_extents(
struct xfs_trans *tp,
struct xfs_inode *ip,
bool *has_shared)
{
struct xfs_bmbt_irec got;
struct xfs_mount *mp = ip->i_mount;
struct xfs_ifork *ifp;
struct xfs_iext_cursor icur;
bool found;
int error;
ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
if (error)
return error;
*has_shared = false;
found = xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got);
while (found) {
struct xfs_perag *pag;
xfs_agblock_t agbno;
xfs_extlen_t aglen;
xfs_agblock_t rbno;
xfs_extlen_t rlen;
if (isnullstartblock(got.br_startblock) ||
got.br_state != XFS_EXT_NORM)
goto next;
pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, got.br_startblock));
agbno = XFS_FSB_TO_AGBNO(mp, got.br_startblock);
aglen = got.br_blockcount;
error = xfs_reflink_find_shared(pag, tp, agbno, aglen,
&rbno, &rlen, false);
xfs_perag_put(pag);
if (error)
return error;
/* Is there still a shared block here? */
if (rbno != NULLAGBLOCK) {
*has_shared = true;
return 0;
}
next:
found = xfs_iext_next_extent(ifp, &icur, &got);
}
return 0;
}
/*
* Clear the inode reflink flag if there are no shared extents.
*
* The caller is responsible for joining the inode to the transaction passed in.
* The inode will be joined to the transaction that is returned to the caller.
*/
int
xfs_reflink_clear_inode_flag(
struct xfs_inode *ip,
struct xfs_trans **tpp)
{
bool needs_flag;
int error = 0;
ASSERT(xfs_is_reflink_inode(ip));
error = xfs_reflink_inode_has_shared_extents(*tpp, ip, &needs_flag);
if (error || needs_flag)
return error;
/*
* We didn't find any shared blocks so turn off the reflink flag.
* First, get rid of any leftover CoW mappings.
*/
error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, XFS_MAX_FILEOFF,
true);
if (error)
return error;
/* Clear the inode flag. */
trace_xfs_reflink_unset_inode_flag(ip);
ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
xfs_inode_clear_cowblocks_tag(ip);
xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
return error;
}
/*
* Clear the inode reflink flag if there are no shared extents and the size
* hasn't changed.
*/
STATIC int
xfs_reflink_try_clear_inode_flag(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int error = 0;
/* Start a rolling transaction to remove the mappings */
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
error = xfs_reflink_clear_inode_flag(ip, &tp);
if (error)
goto cancel;
error = xfs_trans_commit(tp);
if (error)
goto out;
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return 0;
cancel:
xfs_trans_cancel(tp);
out:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
/*
* Pre-COW all shared blocks within a given byte range of a file and turn off
* the reflink flag if we unshare all of the file's blocks.
*/
int
xfs_reflink_unshare(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t len)
{
struct inode *inode = VFS_I(ip);
int error;
if (!xfs_is_reflink_inode(ip))
return 0;
trace_xfs_reflink_unshare(ip, offset, len);
inode_dio_wait(inode);
if (IS_DAX(inode))
error = dax_file_unshare(inode, offset, len,
&xfs_dax_write_iomap_ops);
else
error = iomap_file_unshare(inode, offset, len,
&xfs_buffered_write_iomap_ops);
if (error)
goto out;
error = filemap_write_and_wait_range(inode->i_mapping, offset,
offset + len - 1);
if (error)
goto out;
/* Turn off the reflink flag if possible. */
error = xfs_reflink_try_clear_inode_flag(ip);
if (error)
goto out;
return 0;
out:
trace_xfs_reflink_unshare_error(ip, error, _RET_IP_);
return error;
}
| linux-master | fs/xfs/xfs_reflink.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2008, Christoph Hellwig
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_quota.h"
#include "xfs_trans.h"
#include "xfs_icache.h"
#include "xfs_qm.h"
static void
xfs_qm_fill_state(
struct qc_type_state *tstate,
struct xfs_mount *mp,
struct xfs_inode *ip,
xfs_ino_t ino,
struct xfs_def_quota *defq)
{
bool tempqip = false;
tstate->ino = ino;
if (!ip && ino == NULLFSINO)
return;
if (!ip) {
if (xfs_iget(mp, NULL, ino, 0, 0, &ip))
return;
tempqip = true;
}
tstate->flags |= QCI_SYSFILE;
tstate->blocks = ip->i_nblocks;
tstate->nextents = ip->i_df.if_nextents;
tstate->spc_timelimit = (u32)defq->blk.time;
tstate->ino_timelimit = (u32)defq->ino.time;
tstate->rt_spc_timelimit = (u32)defq->rtb.time;
tstate->spc_warnlimit = 0;
tstate->ino_warnlimit = 0;
tstate->rt_spc_warnlimit = 0;
if (tempqip)
xfs_irele(ip);
}
/*
* Return quota status information, such as enforcements, quota file inode
* numbers etc.
*/
static int
xfs_fs_get_quota_state(
struct super_block *sb,
struct qc_state *state)
{
struct xfs_mount *mp = XFS_M(sb);
struct xfs_quotainfo *q = mp->m_quotainfo;
memset(state, 0, sizeof(*state));
if (!XFS_IS_QUOTA_ON(mp))
return 0;
state->s_incoredqs = q->qi_dquots;
if (XFS_IS_UQUOTA_ON(mp))
state->s_state[USRQUOTA].flags |= QCI_ACCT_ENABLED;
if (XFS_IS_UQUOTA_ENFORCED(mp))
state->s_state[USRQUOTA].flags |= QCI_LIMITS_ENFORCED;
if (XFS_IS_GQUOTA_ON(mp))
state->s_state[GRPQUOTA].flags |= QCI_ACCT_ENABLED;
if (XFS_IS_GQUOTA_ENFORCED(mp))
state->s_state[GRPQUOTA].flags |= QCI_LIMITS_ENFORCED;
if (XFS_IS_PQUOTA_ON(mp))
state->s_state[PRJQUOTA].flags |= QCI_ACCT_ENABLED;
if (XFS_IS_PQUOTA_ENFORCED(mp))
state->s_state[PRJQUOTA].flags |= QCI_LIMITS_ENFORCED;
xfs_qm_fill_state(&state->s_state[USRQUOTA], mp, q->qi_uquotaip,
mp->m_sb.sb_uquotino, &q->qi_usr_default);
xfs_qm_fill_state(&state->s_state[GRPQUOTA], mp, q->qi_gquotaip,
mp->m_sb.sb_gquotino, &q->qi_grp_default);
xfs_qm_fill_state(&state->s_state[PRJQUOTA], mp, q->qi_pquotaip,
mp->m_sb.sb_pquotino, &q->qi_prj_default);
return 0;
}
STATIC xfs_dqtype_t
xfs_quota_type(int type)
{
switch (type) {
case USRQUOTA:
return XFS_DQTYPE_USER;
case GRPQUOTA:
return XFS_DQTYPE_GROUP;
default:
return XFS_DQTYPE_PROJ;
}
}
#define XFS_QC_SETINFO_MASK (QC_TIMER_MASK)
/*
* Adjust quota timers & warnings
*/
static int
xfs_fs_set_info(
struct super_block *sb,
int type,
struct qc_info *info)
{
struct xfs_mount *mp = XFS_M(sb);
struct qc_dqblk newlim;
if (sb_rdonly(sb))
return -EROFS;
if (!XFS_IS_QUOTA_ON(mp))
return -ENOSYS;
if (info->i_fieldmask & ~XFS_QC_SETINFO_MASK)
return -EINVAL;
if ((info->i_fieldmask & XFS_QC_SETINFO_MASK) == 0)
return 0;
newlim.d_fieldmask = info->i_fieldmask;
newlim.d_spc_timer = info->i_spc_timelimit;
newlim.d_ino_timer = info->i_ino_timelimit;
newlim.d_rt_spc_timer = info->i_rt_spc_timelimit;
newlim.d_ino_warns = info->i_ino_warnlimit;
newlim.d_spc_warns = info->i_spc_warnlimit;
newlim.d_rt_spc_warns = info->i_rt_spc_warnlimit;
return xfs_qm_scall_setqlim(mp, 0, xfs_quota_type(type), &newlim);
}
static unsigned int
xfs_quota_flags(unsigned int uflags)
{
unsigned int flags = 0;
if (uflags & FS_QUOTA_UDQ_ACCT)
flags |= XFS_UQUOTA_ACCT;
if (uflags & FS_QUOTA_PDQ_ACCT)
flags |= XFS_PQUOTA_ACCT;
if (uflags & FS_QUOTA_GDQ_ACCT)
flags |= XFS_GQUOTA_ACCT;
if (uflags & FS_QUOTA_UDQ_ENFD)
flags |= XFS_UQUOTA_ENFD;
if (uflags & FS_QUOTA_GDQ_ENFD)
flags |= XFS_GQUOTA_ENFD;
if (uflags & FS_QUOTA_PDQ_ENFD)
flags |= XFS_PQUOTA_ENFD;
return flags;
}
STATIC int
xfs_quota_enable(
struct super_block *sb,
unsigned int uflags)
{
struct xfs_mount *mp = XFS_M(sb);
if (sb_rdonly(sb))
return -EROFS;
if (!XFS_IS_QUOTA_ON(mp))
return -ENOSYS;
return xfs_qm_scall_quotaon(mp, xfs_quota_flags(uflags));
}
STATIC int
xfs_quota_disable(
struct super_block *sb,
unsigned int uflags)
{
struct xfs_mount *mp = XFS_M(sb);
if (sb_rdonly(sb))
return -EROFS;
if (!XFS_IS_QUOTA_ON(mp))
return -ENOSYS;
return xfs_qm_scall_quotaoff(mp, xfs_quota_flags(uflags));
}
STATIC int
xfs_fs_rm_xquota(
struct super_block *sb,
unsigned int uflags)
{
struct xfs_mount *mp = XFS_M(sb);
unsigned int flags = 0;
if (sb_rdonly(sb))
return -EROFS;
if (XFS_IS_QUOTA_ON(mp))
return -EINVAL;
if (uflags & ~(FS_USER_QUOTA | FS_GROUP_QUOTA | FS_PROJ_QUOTA))
return -EINVAL;
if (uflags & FS_USER_QUOTA)
flags |= XFS_QMOPT_UQUOTA;
if (uflags & FS_GROUP_QUOTA)
flags |= XFS_QMOPT_GQUOTA;
if (uflags & FS_PROJ_QUOTA)
flags |= XFS_QMOPT_PQUOTA;
return xfs_qm_scall_trunc_qfiles(mp, flags);
}
STATIC int
xfs_fs_get_dqblk(
struct super_block *sb,
struct kqid qid,
struct qc_dqblk *qdq)
{
struct xfs_mount *mp = XFS_M(sb);
xfs_dqid_t id;
if (!XFS_IS_QUOTA_ON(mp))
return -ENOSYS;
id = from_kqid(&init_user_ns, qid);
return xfs_qm_scall_getquota(mp, id, xfs_quota_type(qid.type), qdq);
}
/* Return quota info for active quota >= this qid */
STATIC int
xfs_fs_get_nextdqblk(
struct super_block *sb,
struct kqid *qid,
struct qc_dqblk *qdq)
{
int ret;
struct xfs_mount *mp = XFS_M(sb);
xfs_dqid_t id;
if (!XFS_IS_QUOTA_ON(mp))
return -ENOSYS;
id = from_kqid(&init_user_ns, *qid);
ret = xfs_qm_scall_getquota_next(mp, &id, xfs_quota_type(qid->type),
qdq);
if (ret)
return ret;
/* ID may be different, so convert back what we got */
*qid = make_kqid(current_user_ns(), qid->type, id);
return 0;
}
STATIC int
xfs_fs_set_dqblk(
struct super_block *sb,
struct kqid qid,
struct qc_dqblk *qdq)
{
struct xfs_mount *mp = XFS_M(sb);
if (sb_rdonly(sb))
return -EROFS;
if (!XFS_IS_QUOTA_ON(mp))
return -ENOSYS;
return xfs_qm_scall_setqlim(mp, from_kqid(&init_user_ns, qid),
xfs_quota_type(qid.type), qdq);
}
const struct quotactl_ops xfs_quotactl_operations = {
.get_state = xfs_fs_get_quota_state,
.set_info = xfs_fs_set_info,
.quota_enable = xfs_quota_enable,
.quota_disable = xfs_quota_disable,
.rm_xquota = xfs_fs_rm_xquota,
.get_dqblk = xfs_fs_get_dqblk,
.get_nextdqblk = xfs_fs_get_nextdqblk,
.set_dqblk = xfs_fs_set_dqblk,
};
| linux-master | fs/xfs/xfs_quotaops.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2001-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_error.h"
static struct ctl_table_header *xfs_table_header;
#ifdef CONFIG_PROC_FS
STATIC int
xfs_stats_clear_proc_handler(
struct ctl_table *ctl,
int write,
void *buffer,
size_t *lenp,
loff_t *ppos)
{
int ret, *valp = ctl->data;
ret = proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
if (!ret && write && *valp) {
xfs_stats_clearall(xfsstats.xs_stats);
xfs_stats_clear = 0;
}
return ret;
}
STATIC int
xfs_panic_mask_proc_handler(
struct ctl_table *ctl,
int write,
void *buffer,
size_t *lenp,
loff_t *ppos)
{
int ret, *valp = ctl->data;
ret = proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
if (!ret && write) {
xfs_panic_mask = *valp;
#ifdef DEBUG
xfs_panic_mask |= (XFS_PTAG_SHUTDOWN_CORRUPT | XFS_PTAG_LOGRES);
#endif
}
return ret;
}
#endif /* CONFIG_PROC_FS */
STATIC int
xfs_deprecated_dointvec_minmax(
struct ctl_table *ctl,
int write,
void *buffer,
size_t *lenp,
loff_t *ppos)
{
if (write) {
printk_ratelimited(KERN_WARNING
"XFS: %s sysctl option is deprecated.\n",
ctl->procname);
}
return proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
}
static struct ctl_table xfs_table[] = {
{
.procname = "irix_sgid_inherit",
.data = &xfs_params.sgid_inherit.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = xfs_deprecated_dointvec_minmax,
.extra1 = &xfs_params.sgid_inherit.min,
.extra2 = &xfs_params.sgid_inherit.max
},
{
.procname = "irix_symlink_mode",
.data = &xfs_params.symlink_mode.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = xfs_deprecated_dointvec_minmax,
.extra1 = &xfs_params.symlink_mode.min,
.extra2 = &xfs_params.symlink_mode.max
},
{
.procname = "panic_mask",
.data = &xfs_params.panic_mask.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = xfs_panic_mask_proc_handler,
.extra1 = &xfs_params.panic_mask.min,
.extra2 = &xfs_params.panic_mask.max
},
{
.procname = "error_level",
.data = &xfs_params.error_level.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.error_level.min,
.extra2 = &xfs_params.error_level.max
},
{
.procname = "xfssyncd_centisecs",
.data = &xfs_params.syncd_timer.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.syncd_timer.min,
.extra2 = &xfs_params.syncd_timer.max
},
{
.procname = "inherit_sync",
.data = &xfs_params.inherit_sync.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.inherit_sync.min,
.extra2 = &xfs_params.inherit_sync.max
},
{
.procname = "inherit_nodump",
.data = &xfs_params.inherit_nodump.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.inherit_nodump.min,
.extra2 = &xfs_params.inherit_nodump.max
},
{
.procname = "inherit_noatime",
.data = &xfs_params.inherit_noatim.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.inherit_noatim.min,
.extra2 = &xfs_params.inherit_noatim.max
},
{
.procname = "inherit_nosymlinks",
.data = &xfs_params.inherit_nosym.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.inherit_nosym.min,
.extra2 = &xfs_params.inherit_nosym.max
},
{
.procname = "rotorstep",
.data = &xfs_params.rotorstep.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.rotorstep.min,
.extra2 = &xfs_params.rotorstep.max
},
{
.procname = "inherit_nodefrag",
.data = &xfs_params.inherit_nodfrg.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.inherit_nodfrg.min,
.extra2 = &xfs_params.inherit_nodfrg.max
},
{
.procname = "filestream_centisecs",
.data = &xfs_params.fstrm_timer.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.fstrm_timer.min,
.extra2 = &xfs_params.fstrm_timer.max,
},
{
.procname = "speculative_prealloc_lifetime",
.data = &xfs_params.blockgc_timer.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &xfs_params.blockgc_timer.min,
.extra2 = &xfs_params.blockgc_timer.max,
},
{
.procname = "speculative_cow_prealloc_lifetime",
.data = &xfs_params.blockgc_timer.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = xfs_deprecated_dointvec_minmax,
.extra1 = &xfs_params.blockgc_timer.min,
.extra2 = &xfs_params.blockgc_timer.max,
},
/* please keep this the last entry */
#ifdef CONFIG_PROC_FS
{
.procname = "stats_clear",
.data = &xfs_params.stats_clear.val,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = xfs_stats_clear_proc_handler,
.extra1 = &xfs_params.stats_clear.min,
.extra2 = &xfs_params.stats_clear.max
},
#endif /* CONFIG_PROC_FS */
{}
};
int
xfs_sysctl_register(void)
{
xfs_table_header = register_sysctl("fs/xfs", xfs_table);
if (!xfs_table_header)
return -ENOMEM;
return 0;
}
void
xfs_sysctl_unregister(void)
{
unregister_sysctl_table(xfs_table_header);
}
| linux-master | fs/xfs/xfs_sysctl.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2019 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_trace.h"
#include "xfs_sysctl.h"
#include "xfs_pwork.h"
#include <linux/nmi.h>
/*
* Parallel Work Queue
* ===================
*
* Abstract away the details of running a large and "obviously" parallelizable
* task across multiple CPUs. Callers initialize the pwork control object with
* a desired level of parallelization and a work function. Next, they embed
* struct xfs_pwork in whatever structure they use to pass work context to a
* worker thread and queue that pwork. The work function will be passed the
* pwork item when it is run (from process context) and any returned error will
* be recorded in xfs_pwork_ctl.error. Work functions should check for errors
* and abort if necessary; the non-zeroness of xfs_pwork_ctl.error does not
* stop workqueue item processing.
*
* This is the rough equivalent of the xfsprogs workqueue code, though we can't
* reuse that name here.
*/
/* Invoke our caller's function. */
static void
xfs_pwork_work(
struct work_struct *work)
{
struct xfs_pwork *pwork;
struct xfs_pwork_ctl *pctl;
int error;
pwork = container_of(work, struct xfs_pwork, work);
pctl = pwork->pctl;
error = pctl->work_fn(pctl->mp, pwork);
if (error && !pctl->error)
pctl->error = error;
if (atomic_dec_and_test(&pctl->nr_work))
wake_up(&pctl->poll_wait);
}
/*
* Set up control data for parallel work. @work_fn is the function that will
* be called. @tag will be written into the kernel threads. @nr_threads is
* the level of parallelism desired, or 0 for no limit.
*/
int
xfs_pwork_init(
struct xfs_mount *mp,
struct xfs_pwork_ctl *pctl,
xfs_pwork_work_fn work_fn,
const char *tag)
{
unsigned int nr_threads = 0;
#ifdef DEBUG
if (xfs_globals.pwork_threads >= 0)
nr_threads = xfs_globals.pwork_threads;
#endif
trace_xfs_pwork_init(mp, nr_threads, current->pid);
pctl->wq = alloc_workqueue("%s-%d",
WQ_UNBOUND | WQ_SYSFS | WQ_FREEZABLE, nr_threads, tag,
current->pid);
if (!pctl->wq)
return -ENOMEM;
pctl->work_fn = work_fn;
pctl->error = 0;
pctl->mp = mp;
atomic_set(&pctl->nr_work, 0);
init_waitqueue_head(&pctl->poll_wait);
return 0;
}
/* Queue some parallel work. */
void
xfs_pwork_queue(
struct xfs_pwork_ctl *pctl,
struct xfs_pwork *pwork)
{
INIT_WORK(&pwork->work, xfs_pwork_work);
pwork->pctl = pctl;
atomic_inc(&pctl->nr_work);
queue_work(pctl->wq, &pwork->work);
}
/* Wait for the work to finish and tear down the control structure. */
int
xfs_pwork_destroy(
struct xfs_pwork_ctl *pctl)
{
destroy_workqueue(pctl->wq);
pctl->wq = NULL;
return pctl->error;
}
/*
* Wait for the work to finish by polling completion status and touch the soft
* lockup watchdog. This is for callers such as mount which hold locks.
*/
void
xfs_pwork_poll(
struct xfs_pwork_ctl *pctl)
{
while (wait_event_timeout(pctl->poll_wait,
atomic_read(&pctl->nr_work) == 0, HZ) == 0)
touch_softlockup_watchdog();
}
| linux-master | fs/xfs/xfs_pwork.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
* Copyright (c) 2010 David Chinner.
* Copyright (c) 2011 Christoph Hellwig.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_shared.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_alloc.h"
#include "xfs_extent_busy.h"
#include "xfs_trace.h"
#include "xfs_trans.h"
#include "xfs_log.h"
#include "xfs_ag.h"
void
xfs_extent_busy_insert(
struct xfs_trans *tp,
struct xfs_perag *pag,
xfs_agblock_t bno,
xfs_extlen_t len,
unsigned int flags)
{
struct xfs_extent_busy *new;
struct xfs_extent_busy *busyp;
struct rb_node **rbp;
struct rb_node *parent = NULL;
new = kmem_zalloc(sizeof(struct xfs_extent_busy), 0);
new->agno = pag->pag_agno;
new->bno = bno;
new->length = len;
INIT_LIST_HEAD(&new->list);
new->flags = flags;
/* trace before insert to be able to see failed inserts */
trace_xfs_extent_busy(tp->t_mountp, pag->pag_agno, bno, len);
spin_lock(&pag->pagb_lock);
rbp = &pag->pagb_tree.rb_node;
while (*rbp) {
parent = *rbp;
busyp = rb_entry(parent, struct xfs_extent_busy, rb_node);
if (new->bno < busyp->bno) {
rbp = &(*rbp)->rb_left;
ASSERT(new->bno + new->length <= busyp->bno);
} else if (new->bno > busyp->bno) {
rbp = &(*rbp)->rb_right;
ASSERT(bno >= busyp->bno + busyp->length);
} else {
ASSERT(0);
}
}
rb_link_node(&new->rb_node, parent, rbp);
rb_insert_color(&new->rb_node, &pag->pagb_tree);
list_add(&new->list, &tp->t_busy);
spin_unlock(&pag->pagb_lock);
}
/*
* Search for a busy extent within the range of the extent we are about to
* allocate. You need to be holding the busy extent tree lock when calling
* xfs_extent_busy_search(). This function returns 0 for no overlapping busy
* extent, -1 for an overlapping but not exact busy extent, and 1 for an exact
* match. This is done so that a non-zero return indicates an overlap that
* will require a synchronous transaction, but it can still be
* used to distinguish between a partial or exact match.
*/
int
xfs_extent_busy_search(
struct xfs_mount *mp,
struct xfs_perag *pag,
xfs_agblock_t bno,
xfs_extlen_t len)
{
struct rb_node *rbp;
struct xfs_extent_busy *busyp;
int match = 0;
/* find closest start bno overlap */
spin_lock(&pag->pagb_lock);
rbp = pag->pagb_tree.rb_node;
while (rbp) {
busyp = rb_entry(rbp, struct xfs_extent_busy, rb_node);
if (bno < busyp->bno) {
/* may overlap, but exact start block is lower */
if (bno + len > busyp->bno)
match = -1;
rbp = rbp->rb_left;
} else if (bno > busyp->bno) {
/* may overlap, but exact start block is higher */
if (bno < busyp->bno + busyp->length)
match = -1;
rbp = rbp->rb_right;
} else {
/* bno matches busyp, length determines exact match */
match = (busyp->length == len) ? 1 : -1;
break;
}
}
spin_unlock(&pag->pagb_lock);
return match;
}
/*
* The found free extent [fbno, fend] overlaps part or all of the given busy
* extent. If the overlap covers the beginning, the end, or all of the busy
* extent, the overlapping portion can be made unbusy and used for the
* allocation. We can't split a busy extent because we can't modify a
* transaction/CIL context busy list, but we can update an entry's block
* number or length.
*
* Returns true if the extent can safely be reused, or false if the search
* needs to be restarted.
*/
STATIC bool
xfs_extent_busy_update_extent(
struct xfs_mount *mp,
struct xfs_perag *pag,
struct xfs_extent_busy *busyp,
xfs_agblock_t fbno,
xfs_extlen_t flen,
bool userdata) __releases(&pag->pagb_lock)
__acquires(&pag->pagb_lock)
{
xfs_agblock_t fend = fbno + flen;
xfs_agblock_t bbno = busyp->bno;
xfs_agblock_t bend = bbno + busyp->length;
/*
* This extent is currently being discarded. Give the thread
* performing the discard a chance to mark the extent unbusy
* and retry.
*/
if (busyp->flags & XFS_EXTENT_BUSY_DISCARDED) {
spin_unlock(&pag->pagb_lock);
delay(1);
spin_lock(&pag->pagb_lock);
return false;
}
/*
* If there is a busy extent overlapping a user allocation, we have
* no choice but to force the log and retry the search.
*
* Fortunately this does not happen during normal operation, but
* only if the filesystem is very low on space and has to dip into
* the AGFL for normal allocations.
*/
if (userdata)
goto out_force_log;
if (bbno < fbno && bend > fend) {
/*
* Case 1:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +---------+
* fbno fend
*/
/*
* We would have to split the busy extent to be able to track
* it correct, which we cannot do because we would have to
* modify the list of busy extents attached to the transaction
* or CIL context, which is immutable.
*
* Force out the log to clear the busy extent and retry the
* search.
*/
goto out_force_log;
} else if (bbno >= fbno && bend <= fend) {
/*
* Case 2:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +-----------------+
* fbno fend
*
* Case 3:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +--------------------------+
* fbno fend
*
* Case 4:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +--------------------------+
* fbno fend
*
* Case 5:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +-----------------------------------+
* fbno fend
*
*/
/*
* The busy extent is fully covered by the extent we are
* allocating, and can simply be removed from the rbtree.
* However we cannot remove it from the immutable list
* tracking busy extents in the transaction or CIL context,
* so set the length to zero to mark it invalid.
*
* We also need to restart the busy extent search from the
* tree root, because erasing the node can rearrange the
* tree topology.
*/
rb_erase(&busyp->rb_node, &pag->pagb_tree);
busyp->length = 0;
return false;
} else if (fend < bend) {
/*
* Case 6:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +---------+
* fbno fend
*
* Case 7:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +------------------+
* fbno fend
*
*/
busyp->bno = fend;
busyp->length = bend - fend;
} else if (bbno < fbno) {
/*
* Case 8:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +-------------+
* fbno fend
*
* Case 9:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +----------------------+
* fbno fend
*/
busyp->length = fbno - busyp->bno;
} else {
ASSERT(0);
}
trace_xfs_extent_busy_reuse(mp, pag->pag_agno, fbno, flen);
return true;
out_force_log:
spin_unlock(&pag->pagb_lock);
xfs_log_force(mp, XFS_LOG_SYNC);
trace_xfs_extent_busy_force(mp, pag->pag_agno, fbno, flen);
spin_lock(&pag->pagb_lock);
return false;
}
/*
* For a given extent [fbno, flen], make sure we can reuse it safely.
*/
void
xfs_extent_busy_reuse(
struct xfs_mount *mp,
struct xfs_perag *pag,
xfs_agblock_t fbno,
xfs_extlen_t flen,
bool userdata)
{
struct rb_node *rbp;
ASSERT(flen > 0);
spin_lock(&pag->pagb_lock);
restart:
rbp = pag->pagb_tree.rb_node;
while (rbp) {
struct xfs_extent_busy *busyp =
rb_entry(rbp, struct xfs_extent_busy, rb_node);
xfs_agblock_t bbno = busyp->bno;
xfs_agblock_t bend = bbno + busyp->length;
if (fbno + flen <= bbno) {
rbp = rbp->rb_left;
continue;
} else if (fbno >= bend) {
rbp = rbp->rb_right;
continue;
}
if (!xfs_extent_busy_update_extent(mp, pag, busyp, fbno, flen,
userdata))
goto restart;
}
spin_unlock(&pag->pagb_lock);
}
/*
* For a given extent [fbno, flen], search the busy extent list to find a
* subset of the extent that is not busy. If *rlen is smaller than
* args->minlen no suitable extent could be found, and the higher level
* code needs to force out the log and retry the allocation.
*
* Return the current busy generation for the AG if the extent is busy. This
* value can be used to wait for at least one of the currently busy extents
* to be cleared. Note that the busy list is not guaranteed to be empty after
* the gen is woken. The state of a specific extent must always be confirmed
* with another call to xfs_extent_busy_trim() before it can be used.
*/
bool
xfs_extent_busy_trim(
struct xfs_alloc_arg *args,
xfs_agblock_t *bno,
xfs_extlen_t *len,
unsigned *busy_gen)
{
xfs_agblock_t fbno;
xfs_extlen_t flen;
struct rb_node *rbp;
bool ret = false;
ASSERT(*len > 0);
spin_lock(&args->pag->pagb_lock);
fbno = *bno;
flen = *len;
rbp = args->pag->pagb_tree.rb_node;
while (rbp && flen >= args->minlen) {
struct xfs_extent_busy *busyp =
rb_entry(rbp, struct xfs_extent_busy, rb_node);
xfs_agblock_t fend = fbno + flen;
xfs_agblock_t bbno = busyp->bno;
xfs_agblock_t bend = bbno + busyp->length;
if (fend <= bbno) {
rbp = rbp->rb_left;
continue;
} else if (fbno >= bend) {
rbp = rbp->rb_right;
continue;
}
if (bbno <= fbno) {
/* start overlap */
/*
* Case 1:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +---------+
* fbno fend
*
* Case 2:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +-------------+
* fbno fend
*
* Case 3:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +-------------+
* fbno fend
*
* Case 4:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +-----------------+
* fbno fend
*
* No unbusy region in extent, return failure.
*/
if (fend <= bend)
goto fail;
/*
* Case 5:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +----------------------+
* fbno fend
*
* Case 6:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +--------------------------+
* fbno fend
*
* Needs to be trimmed to:
* +-------+
* fbno fend
*/
fbno = bend;
} else if (bend >= fend) {
/* end overlap */
/*
* Case 7:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +------------------+
* fbno fend
*
* Case 8:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +--------------------------+
* fbno fend
*
* Needs to be trimmed to:
* +-------+
* fbno fend
*/
fend = bbno;
} else {
/* middle overlap */
/*
* Case 9:
* bbno bend
* +BBBBBBBBBBBBBBBBB+
* +-----------------------------------+
* fbno fend
*
* Can be trimmed to:
* +-------+ OR +-------+
* fbno fend fbno fend
*
* Backward allocation leads to significant
* fragmentation of directories, which degrades
* directory performance, therefore we always want to
* choose the option that produces forward allocation
* patterns.
* Preferring the lower bno extent will make the next
* request use "fend" as the start of the next
* allocation; if the segment is no longer busy at
* that point, we'll get a contiguous allocation, but
* even if it is still busy, we will get a forward
* allocation.
* We try to avoid choosing the segment at "bend",
* because that can lead to the next allocation
* taking the segment at "fbno", which would be a
* backward allocation. We only use the segment at
* "fbno" if it is much larger than the current
* requested size, because in that case there's a
* good chance subsequent allocations will be
* contiguous.
*/
if (bbno - fbno >= args->maxlen) {
/* left candidate fits perfect */
fend = bbno;
} else if (fend - bend >= args->maxlen * 4) {
/* right candidate has enough free space */
fbno = bend;
} else if (bbno - fbno >= args->minlen) {
/* left candidate fits minimum requirement */
fend = bbno;
} else {
goto fail;
}
}
flen = fend - fbno;
}
out:
if (fbno != *bno || flen != *len) {
trace_xfs_extent_busy_trim(args->mp, args->agno, *bno, *len,
fbno, flen);
*bno = fbno;
*len = flen;
*busy_gen = args->pag->pagb_gen;
ret = true;
}
spin_unlock(&args->pag->pagb_lock);
return ret;
fail:
/*
* Return a zero extent length as failure indications. All callers
* re-check if the trimmed extent satisfies the minlen requirement.
*/
flen = 0;
goto out;
}
STATIC void
xfs_extent_busy_clear_one(
struct xfs_mount *mp,
struct xfs_perag *pag,
struct xfs_extent_busy *busyp)
{
if (busyp->length) {
trace_xfs_extent_busy_clear(mp, busyp->agno, busyp->bno,
busyp->length);
rb_erase(&busyp->rb_node, &pag->pagb_tree);
}
list_del_init(&busyp->list);
kmem_free(busyp);
}
static void
xfs_extent_busy_put_pag(
struct xfs_perag *pag,
bool wakeup)
__releases(pag->pagb_lock)
{
if (wakeup) {
pag->pagb_gen++;
wake_up_all(&pag->pagb_wait);
}
spin_unlock(&pag->pagb_lock);
xfs_perag_put(pag);
}
/*
* Remove all extents on the passed in list from the busy extents tree.
* If do_discard is set skip extents that need to be discarded, and mark
* these as undergoing a discard operation instead.
*/
void
xfs_extent_busy_clear(
struct xfs_mount *mp,
struct list_head *list,
bool do_discard)
{
struct xfs_extent_busy *busyp, *n;
struct xfs_perag *pag = NULL;
xfs_agnumber_t agno = NULLAGNUMBER;
bool wakeup = false;
list_for_each_entry_safe(busyp, n, list, list) {
if (busyp->agno != agno) {
if (pag)
xfs_extent_busy_put_pag(pag, wakeup);
agno = busyp->agno;
pag = xfs_perag_get(mp, agno);
spin_lock(&pag->pagb_lock);
wakeup = false;
}
if (do_discard && busyp->length &&
!(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD)) {
busyp->flags = XFS_EXTENT_BUSY_DISCARDED;
} else {
xfs_extent_busy_clear_one(mp, pag, busyp);
wakeup = true;
}
}
if (pag)
xfs_extent_busy_put_pag(pag, wakeup);
}
/*
* Flush out all busy extents for this AG.
*
* If the current transaction is holding busy extents, the caller may not want
* to wait for committed busy extents to resolve. If we are being told just to
* try a flush or progress has been made since we last skipped a busy extent,
* return immediately to allow the caller to try again.
*
* If we are freeing extents, we might actually be holding the only free extents
* in the transaction busy list and the log force won't resolve that situation.
* In this case, we must return -EAGAIN to avoid a deadlock by informing the
* caller it needs to commit the busy extents it holds before retrying the
* extent free operation.
*/
int
xfs_extent_busy_flush(
struct xfs_trans *tp,
struct xfs_perag *pag,
unsigned busy_gen,
uint32_t alloc_flags)
{
DEFINE_WAIT (wait);
int error;
error = xfs_log_force(tp->t_mountp, XFS_LOG_SYNC);
if (error)
return error;
/* Avoid deadlocks on uncommitted busy extents. */
if (!list_empty(&tp->t_busy)) {
if (alloc_flags & XFS_ALLOC_FLAG_TRYFLUSH)
return 0;
if (busy_gen != READ_ONCE(pag->pagb_gen))
return 0;
if (alloc_flags & XFS_ALLOC_FLAG_FREEING)
return -EAGAIN;
}
/* Wait for committed busy extents to resolve. */
do {
prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
if (busy_gen != READ_ONCE(pag->pagb_gen))
break;
schedule();
} while (1);
finish_wait(&pag->pagb_wait, &wait);
return 0;
}
void
xfs_extent_busy_wait_all(
struct xfs_mount *mp)
{
struct xfs_perag *pag;
DEFINE_WAIT (wait);
xfs_agnumber_t agno;
for_each_perag(mp, agno, pag) {
do {
prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
if (RB_EMPTY_ROOT(&pag->pagb_tree))
break;
schedule();
} while (1);
finish_wait(&pag->pagb_wait, &wait);
}
}
/*
* Callback for list_sort to sort busy extents by the AG they reside in.
*/
int
xfs_extent_busy_ag_cmp(
void *priv,
const struct list_head *l1,
const struct list_head *l2)
{
struct xfs_extent_busy *b1 =
container_of(l1, struct xfs_extent_busy, list);
struct xfs_extent_busy *b2 =
container_of(l2, struct xfs_extent_busy, list);
s32 diff;
diff = b1->agno - b2->agno;
if (!diff)
diff = b1->bno - b2->bno;
return diff;
}
| linux-master | fs/xfs/xfs_extent_busy.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2019 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_ialloc_btree.h"
#include "xfs_iwalk.h"
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_health.h"
#include "xfs_trans.h"
#include "xfs_pwork.h"
#include "xfs_ag.h"
/*
* Walking Inodes in the Filesystem
* ================================
*
* This iterator function walks a subset of filesystem inodes in increasing
* order from @startino until there are no more inodes. For each allocated
* inode it finds, it calls a walk function with the relevant inode number and
* a pointer to caller-provided data. The walk function can return the usual
* negative error code to stop the iteration; 0 to continue the iteration; or
* -ECANCELED to stop the iteration. This return value is returned to the
* caller.
*
* Internally, we allow the walk function to do anything, which means that we
* cannot maintain the inobt cursor or our lock on the AGI buffer. We
* therefore cache the inobt records in kernel memory and only call the walk
* function when our memory buffer is full. @nr_recs is the number of records
* that we've cached, and @sz_recs is the size of our cache.
*
* It is the responsibility of the walk function to ensure it accesses
* allocated inodes, as the inobt records may be stale by the time they are
* acted upon.
*/
struct xfs_iwalk_ag {
/* parallel work control data; will be null if single threaded */
struct xfs_pwork pwork;
struct xfs_mount *mp;
struct xfs_trans *tp;
struct xfs_perag *pag;
/* Where do we start the traversal? */
xfs_ino_t startino;
/* What was the last inode number we saw when iterating the inobt? */
xfs_ino_t lastino;
/* Array of inobt records we cache. */
struct xfs_inobt_rec_incore *recs;
/* Number of entries allocated for the @recs array. */
unsigned int sz_recs;
/* Number of entries in the @recs array that are in use. */
unsigned int nr_recs;
/* Inode walk function and data pointer. */
xfs_iwalk_fn iwalk_fn;
xfs_inobt_walk_fn inobt_walk_fn;
void *data;
/*
* Make it look like the inodes up to startino are free so that
* bulkstat can start its inode iteration at the correct place without
* needing to special case everywhere.
*/
unsigned int trim_start:1;
/* Skip empty inobt records? */
unsigned int skip_empty:1;
/* Drop the (hopefully empty) transaction when calling iwalk_fn. */
unsigned int drop_trans:1;
};
/*
* Loop over all clusters in a chunk for a given incore inode allocation btree
* record. Do a readahead if there are any allocated inodes in that cluster.
*/
STATIC void
xfs_iwalk_ichunk_ra(
struct xfs_mount *mp,
struct xfs_perag *pag,
struct xfs_inobt_rec_incore *irec)
{
struct xfs_ino_geometry *igeo = M_IGEO(mp);
xfs_agblock_t agbno;
struct blk_plug plug;
int i; /* inode chunk index */
agbno = XFS_AGINO_TO_AGBNO(mp, irec->ir_startino);
blk_start_plug(&plug);
for (i = 0; i < XFS_INODES_PER_CHUNK; i += igeo->inodes_per_cluster) {
xfs_inofree_t imask;
imask = xfs_inobt_maskn(i, igeo->inodes_per_cluster);
if (imask & ~irec->ir_free) {
xfs_btree_reada_bufs(mp, pag->pag_agno, agbno,
igeo->blocks_per_cluster,
&xfs_inode_buf_ops);
}
agbno += igeo->blocks_per_cluster;
}
blk_finish_plug(&plug);
}
/*
* Set the bits in @irec's free mask that correspond to the inodes before
* @agino so that we skip them. This is how we restart an inode walk that was
* interrupted in the middle of an inode record.
*/
STATIC void
xfs_iwalk_adjust_start(
xfs_agino_t agino, /* starting inode of chunk */
struct xfs_inobt_rec_incore *irec) /* btree record */
{
int idx; /* index into inode chunk */
int i;
idx = agino - irec->ir_startino;
/*
* We got a right chunk with some left inodes allocated at it. Grab
* the chunk record. Mark all the uninteresting inodes free because
* they're before our start point.
*/
for (i = 0; i < idx; i++) {
if (XFS_INOBT_MASK(i) & ~irec->ir_free)
irec->ir_freecount++;
}
irec->ir_free |= xfs_inobt_maskn(0, idx);
}
/* Allocate memory for a walk. */
STATIC int
xfs_iwalk_alloc(
struct xfs_iwalk_ag *iwag)
{
size_t size;
ASSERT(iwag->recs == NULL);
iwag->nr_recs = 0;
/* Allocate a prefetch buffer for inobt records. */
size = iwag->sz_recs * sizeof(struct xfs_inobt_rec_incore);
iwag->recs = kmem_alloc(size, KM_MAYFAIL);
if (iwag->recs == NULL)
return -ENOMEM;
return 0;
}
/* Free memory we allocated for a walk. */
STATIC void
xfs_iwalk_free(
struct xfs_iwalk_ag *iwag)
{
kmem_free(iwag->recs);
iwag->recs = NULL;
}
/* For each inuse inode in each cached inobt record, call our function. */
STATIC int
xfs_iwalk_ag_recs(
struct xfs_iwalk_ag *iwag)
{
struct xfs_mount *mp = iwag->mp;
struct xfs_trans *tp = iwag->tp;
struct xfs_perag *pag = iwag->pag;
xfs_ino_t ino;
unsigned int i, j;
int error;
for (i = 0; i < iwag->nr_recs; i++) {
struct xfs_inobt_rec_incore *irec = &iwag->recs[i];
trace_xfs_iwalk_ag_rec(mp, pag->pag_agno, irec);
if (xfs_pwork_want_abort(&iwag->pwork))
return 0;
if (iwag->inobt_walk_fn) {
error = iwag->inobt_walk_fn(mp, tp, pag->pag_agno, irec,
iwag->data);
if (error)
return error;
}
if (!iwag->iwalk_fn)
continue;
for (j = 0; j < XFS_INODES_PER_CHUNK; j++) {
if (xfs_pwork_want_abort(&iwag->pwork))
return 0;
/* Skip if this inode is free */
if (XFS_INOBT_MASK(j) & irec->ir_free)
continue;
/* Otherwise call our function. */
ino = XFS_AGINO_TO_INO(mp, pag->pag_agno,
irec->ir_startino + j);
error = iwag->iwalk_fn(mp, tp, ino, iwag->data);
if (error)
return error;
}
}
return 0;
}
/* Delete cursor and let go of AGI. */
static inline void
xfs_iwalk_del_inobt(
struct xfs_trans *tp,
struct xfs_btree_cur **curpp,
struct xfs_buf **agi_bpp,
int error)
{
if (*curpp) {
xfs_btree_del_cursor(*curpp, error);
*curpp = NULL;
}
if (*agi_bpp) {
xfs_trans_brelse(tp, *agi_bpp);
*agi_bpp = NULL;
}
}
/*
* Set ourselves up for walking inobt records starting from a given point in
* the filesystem.
*
* If caller passed in a nonzero start inode number, load the record from the
* inobt and make the record look like all the inodes before agino are free so
* that we skip them, and then move the cursor to the next inobt record. This
* is how we support starting an iwalk in the middle of an inode chunk.
*
* If the caller passed in a start number of zero, move the cursor to the first
* inobt record.
*
* The caller is responsible for cleaning up the cursor and buffer pointer
* regardless of the error status.
*/
STATIC int
xfs_iwalk_ag_start(
struct xfs_iwalk_ag *iwag,
xfs_agino_t agino,
struct xfs_btree_cur **curpp,
struct xfs_buf **agi_bpp,
int *has_more)
{
struct xfs_mount *mp = iwag->mp;
struct xfs_trans *tp = iwag->tp;
struct xfs_perag *pag = iwag->pag;
struct xfs_inobt_rec_incore *irec;
int error;
/* Set up a fresh cursor and empty the inobt cache. */
iwag->nr_recs = 0;
error = xfs_inobt_cur(pag, tp, XFS_BTNUM_INO, curpp, agi_bpp);
if (error)
return error;
/* Starting at the beginning of the AG? That's easy! */
if (agino == 0)
return xfs_inobt_lookup(*curpp, 0, XFS_LOOKUP_GE, has_more);
/*
* Otherwise, we have to grab the inobt record where we left off, stuff
* the record into our cache, and then see if there are more records.
* We require a lookup cache of at least two elements so that the
* caller doesn't have to deal with tearing down the cursor to walk the
* records.
*/
error = xfs_inobt_lookup(*curpp, agino, XFS_LOOKUP_LE, has_more);
if (error)
return error;
/*
* If the LE lookup at @agino yields no records, jump ahead to the
* inobt cursor increment to see if there are more records to process.
*/
if (!*has_more)
goto out_advance;
/* Get the record, should always work */
irec = &iwag->recs[iwag->nr_recs];
error = xfs_inobt_get_rec(*curpp, irec, has_more);
if (error)
return error;
if (XFS_IS_CORRUPT(mp, *has_more != 1))
return -EFSCORRUPTED;
iwag->lastino = XFS_AGINO_TO_INO(mp, pag->pag_agno,
irec->ir_startino + XFS_INODES_PER_CHUNK - 1);
/*
* If the LE lookup yielded an inobt record before the cursor position,
* skip it and see if there's another one after it.
*/
if (irec->ir_startino + XFS_INODES_PER_CHUNK <= agino)
goto out_advance;
/*
* If agino fell in the middle of the inode record, make it look like
* the inodes up to agino are free so that we don't return them again.
*/
if (iwag->trim_start)
xfs_iwalk_adjust_start(agino, irec);
/*
* The prefetch calculation is supposed to give us a large enough inobt
* record cache that grab_ichunk can stage a partial first record and
* the loop body can cache a record without having to check for cache
* space until after it reads an inobt record.
*/
iwag->nr_recs++;
ASSERT(iwag->nr_recs < iwag->sz_recs);
out_advance:
return xfs_btree_increment(*curpp, 0, has_more);
}
/*
* The inobt record cache is full, so preserve the inobt cursor state and
* run callbacks on the cached inobt records. When we're done, restore the
* cursor state to wherever the cursor would have been had the cache not been
* full (and therefore we could've just incremented the cursor) if *@has_more
* is true. On exit, *@has_more will indicate whether or not the caller should
* try for more inode records.
*/
STATIC int
xfs_iwalk_run_callbacks(
struct xfs_iwalk_ag *iwag,
struct xfs_btree_cur **curpp,
struct xfs_buf **agi_bpp,
int *has_more)
{
struct xfs_mount *mp = iwag->mp;
struct xfs_inobt_rec_incore *irec;
xfs_agino_t next_agino;
int error;
next_agino = XFS_INO_TO_AGINO(mp, iwag->lastino) + 1;
ASSERT(iwag->nr_recs > 0);
/* Delete cursor but remember the last record we cached... */
xfs_iwalk_del_inobt(iwag->tp, curpp, agi_bpp, 0);
irec = &iwag->recs[iwag->nr_recs - 1];
ASSERT(next_agino >= irec->ir_startino + XFS_INODES_PER_CHUNK);
if (iwag->drop_trans) {
xfs_trans_cancel(iwag->tp);
iwag->tp = NULL;
}
error = xfs_iwalk_ag_recs(iwag);
if (error)
return error;
/* ...empty the cache... */
iwag->nr_recs = 0;
if (!has_more)
return 0;
if (iwag->drop_trans) {
error = xfs_trans_alloc_empty(mp, &iwag->tp);
if (error)
return error;
}
/* ...and recreate the cursor just past where we left off. */
error = xfs_inobt_cur(iwag->pag, iwag->tp, XFS_BTNUM_INO, curpp,
agi_bpp);
if (error)
return error;
return xfs_inobt_lookup(*curpp, next_agino, XFS_LOOKUP_GE, has_more);
}
/* Walk all inodes in a single AG, from @iwag->startino to the end of the AG. */
STATIC int
xfs_iwalk_ag(
struct xfs_iwalk_ag *iwag)
{
struct xfs_mount *mp = iwag->mp;
struct xfs_perag *pag = iwag->pag;
struct xfs_buf *agi_bp = NULL;
struct xfs_btree_cur *cur = NULL;
xfs_agino_t agino;
int has_more;
int error = 0;
/* Set up our cursor at the right place in the inode btree. */
ASSERT(pag->pag_agno == XFS_INO_TO_AGNO(mp, iwag->startino));
agino = XFS_INO_TO_AGINO(mp, iwag->startino);
error = xfs_iwalk_ag_start(iwag, agino, &cur, &agi_bp, &has_more);
while (!error && has_more) {
struct xfs_inobt_rec_incore *irec;
xfs_ino_t rec_fsino;
cond_resched();
if (xfs_pwork_want_abort(&iwag->pwork))
goto out;
/* Fetch the inobt record. */
irec = &iwag->recs[iwag->nr_recs];
error = xfs_inobt_get_rec(cur, irec, &has_more);
if (error || !has_more)
break;
/* Make sure that we always move forward. */
rec_fsino = XFS_AGINO_TO_INO(mp, pag->pag_agno, irec->ir_startino);
if (iwag->lastino != NULLFSINO &&
XFS_IS_CORRUPT(mp, iwag->lastino >= rec_fsino)) {
error = -EFSCORRUPTED;
goto out;
}
iwag->lastino = rec_fsino + XFS_INODES_PER_CHUNK - 1;
/* No allocated inodes in this chunk; skip it. */
if (iwag->skip_empty && irec->ir_freecount == irec->ir_count) {
error = xfs_btree_increment(cur, 0, &has_more);
if (error)
break;
continue;
}
/*
* Start readahead for this inode chunk in anticipation of
* walking the inodes.
*/
if (iwag->iwalk_fn)
xfs_iwalk_ichunk_ra(mp, pag, irec);
/*
* If there's space in the buffer for more records, increment
* the btree cursor and grab more.
*/
if (++iwag->nr_recs < iwag->sz_recs) {
error = xfs_btree_increment(cur, 0, &has_more);
if (error || !has_more)
break;
continue;
}
/*
* Otherwise, we need to save cursor state and run the callback
* function on the cached records. The run_callbacks function
* is supposed to return a cursor pointing to the record where
* we would be if we had been able to increment like above.
*/
ASSERT(has_more);
error = xfs_iwalk_run_callbacks(iwag, &cur, &agi_bp, &has_more);
}
if (iwag->nr_recs == 0 || error)
goto out;
/* Walk the unprocessed records in the cache. */
error = xfs_iwalk_run_callbacks(iwag, &cur, &agi_bp, &has_more);
out:
xfs_iwalk_del_inobt(iwag->tp, &cur, &agi_bp, error);
return error;
}
/*
* We experimentally determined that the reduction in ioctl call overhead
* diminishes when userspace asks for more than 2048 inodes, so we'll cap
* prefetch at this point.
*/
#define IWALK_MAX_INODE_PREFETCH (2048U)
/*
* Given the number of inodes to prefetch, set the number of inobt records that
* we cache in memory, which controls the number of inodes we try to read
* ahead. Set the maximum if @inodes == 0.
*/
static inline unsigned int
xfs_iwalk_prefetch(
unsigned int inodes)
{
unsigned int inobt_records;
/*
* If the caller didn't tell us the number of inodes they wanted,
* assume the maximum prefetch possible for best performance.
* Otherwise, cap prefetch at that maximum so that we don't start an
* absurd amount of prefetch.
*/
if (inodes == 0)
inodes = IWALK_MAX_INODE_PREFETCH;
inodes = min(inodes, IWALK_MAX_INODE_PREFETCH);
/* Round the inode count up to a full chunk. */
inodes = round_up(inodes, XFS_INODES_PER_CHUNK);
/*
* In order to convert the number of inodes to prefetch into an
* estimate of the number of inobt records to cache, we require a
* conversion factor that reflects our expectations of the average
* loading factor of an inode chunk. Based on data gathered, most
* (but not all) filesystems manage to keep the inode chunks totally
* full, so we'll underestimate slightly so that our readahead will
* still deliver the performance we want on aging filesystems:
*
* inobt = inodes / (INODES_PER_CHUNK * (4 / 5));
*
* The funny math is to avoid integer division.
*/
inobt_records = (inodes * 5) / (4 * XFS_INODES_PER_CHUNK);
/*
* Allocate enough space to prefetch at least two inobt records so that
* we can cache both the record where the iwalk started and the next
* record. This simplifies the AG inode walk loop setup code.
*/
return max(inobt_records, 2U);
}
/*
* Walk all inodes in the filesystem starting from @startino. The @iwalk_fn
* will be called for each allocated inode, being passed the inode's number and
* @data. @max_prefetch controls how many inobt records' worth of inodes we
* try to readahead.
*/
int
xfs_iwalk(
struct xfs_mount *mp,
struct xfs_trans *tp,
xfs_ino_t startino,
unsigned int flags,
xfs_iwalk_fn iwalk_fn,
unsigned int inode_records,
void *data)
{
struct xfs_iwalk_ag iwag = {
.mp = mp,
.tp = tp,
.iwalk_fn = iwalk_fn,
.data = data,
.startino = startino,
.sz_recs = xfs_iwalk_prefetch(inode_records),
.trim_start = 1,
.skip_empty = 1,
.pwork = XFS_PWORK_SINGLE_THREADED,
.lastino = NULLFSINO,
};
struct xfs_perag *pag;
xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, startino);
int error;
ASSERT(agno < mp->m_sb.sb_agcount);
ASSERT(!(flags & ~XFS_IWALK_FLAGS_ALL));
error = xfs_iwalk_alloc(&iwag);
if (error)
return error;
for_each_perag_from(mp, agno, pag) {
iwag.pag = pag;
error = xfs_iwalk_ag(&iwag);
if (error)
break;
iwag.startino = XFS_AGINO_TO_INO(mp, agno + 1, 0);
if (flags & XFS_INOBT_WALK_SAME_AG)
break;
iwag.pag = NULL;
}
if (iwag.pag)
xfs_perag_rele(pag);
xfs_iwalk_free(&iwag);
return error;
}
/* Run per-thread iwalk work. */
static int
xfs_iwalk_ag_work(
struct xfs_mount *mp,
struct xfs_pwork *pwork)
{
struct xfs_iwalk_ag *iwag;
int error = 0;
iwag = container_of(pwork, struct xfs_iwalk_ag, pwork);
if (xfs_pwork_want_abort(pwork))
goto out;
error = xfs_iwalk_alloc(iwag);
if (error)
goto out;
/*
* Grab an empty transaction so that we can use its recursive buffer
* locking abilities to detect cycles in the inobt without deadlocking.
*/
error = xfs_trans_alloc_empty(mp, &iwag->tp);
if (error)
goto out;
iwag->drop_trans = 1;
error = xfs_iwalk_ag(iwag);
if (iwag->tp)
xfs_trans_cancel(iwag->tp);
xfs_iwalk_free(iwag);
out:
xfs_perag_put(iwag->pag);
kmem_free(iwag);
return error;
}
/*
* Walk all the inodes in the filesystem using multiple threads to process each
* AG.
*/
int
xfs_iwalk_threaded(
struct xfs_mount *mp,
xfs_ino_t startino,
unsigned int flags,
xfs_iwalk_fn iwalk_fn,
unsigned int inode_records,
bool polled,
void *data)
{
struct xfs_pwork_ctl pctl;
struct xfs_perag *pag;
xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, startino);
int error;
ASSERT(agno < mp->m_sb.sb_agcount);
ASSERT(!(flags & ~XFS_IWALK_FLAGS_ALL));
error = xfs_pwork_init(mp, &pctl, xfs_iwalk_ag_work, "xfs_iwalk");
if (error)
return error;
for_each_perag_from(mp, agno, pag) {
struct xfs_iwalk_ag *iwag;
if (xfs_pwork_ctl_want_abort(&pctl))
break;
iwag = kmem_zalloc(sizeof(struct xfs_iwalk_ag), 0);
iwag->mp = mp;
/*
* perag is being handed off to async work, so take a passive
* reference for the async work to release.
*/
iwag->pag = xfs_perag_hold(pag);
iwag->iwalk_fn = iwalk_fn;
iwag->data = data;
iwag->startino = startino;
iwag->sz_recs = xfs_iwalk_prefetch(inode_records);
iwag->lastino = NULLFSINO;
xfs_pwork_queue(&pctl, &iwag->pwork);
startino = XFS_AGINO_TO_INO(mp, pag->pag_agno + 1, 0);
if (flags & XFS_INOBT_WALK_SAME_AG)
break;
}
if (pag)
xfs_perag_rele(pag);
if (polled)
xfs_pwork_poll(&pctl);
return xfs_pwork_destroy(&pctl);
}
/*
* Allow callers to cache up to a page's worth of inobt records. This reflects
* the existing inumbers prefetching behavior. Since the inobt walk does not
* itself do anything with the inobt records, we can set a fairly high limit
* here.
*/
#define MAX_INOBT_WALK_PREFETCH \
(PAGE_SIZE / sizeof(struct xfs_inobt_rec_incore))
/*
* Given the number of records that the user wanted, set the number of inobt
* records that we buffer in memory. Set the maximum if @inobt_records == 0.
*/
static inline unsigned int
xfs_inobt_walk_prefetch(
unsigned int inobt_records)
{
/*
* If the caller didn't tell us the number of inobt records they
* wanted, assume the maximum prefetch possible for best performance.
*/
if (inobt_records == 0)
inobt_records = MAX_INOBT_WALK_PREFETCH;
/*
* Allocate enough space to prefetch at least two inobt records so that
* we can cache both the record where the iwalk started and the next
* record. This simplifies the AG inode walk loop setup code.
*/
inobt_records = max(inobt_records, 2U);
/*
* Cap prefetch at that maximum so that we don't use an absurd amount
* of memory.
*/
return min_t(unsigned int, inobt_records, MAX_INOBT_WALK_PREFETCH);
}
/*
* Walk all inode btree records in the filesystem starting from @startino. The
* @inobt_walk_fn will be called for each btree record, being passed the incore
* record and @data. @max_prefetch controls how many inobt records we try to
* cache ahead of time.
*/
int
xfs_inobt_walk(
struct xfs_mount *mp,
struct xfs_trans *tp,
xfs_ino_t startino,
unsigned int flags,
xfs_inobt_walk_fn inobt_walk_fn,
unsigned int inobt_records,
void *data)
{
struct xfs_iwalk_ag iwag = {
.mp = mp,
.tp = tp,
.inobt_walk_fn = inobt_walk_fn,
.data = data,
.startino = startino,
.sz_recs = xfs_inobt_walk_prefetch(inobt_records),
.pwork = XFS_PWORK_SINGLE_THREADED,
.lastino = NULLFSINO,
};
struct xfs_perag *pag;
xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, startino);
int error;
ASSERT(agno < mp->m_sb.sb_agcount);
ASSERT(!(flags & ~XFS_INOBT_WALK_FLAGS_ALL));
error = xfs_iwalk_alloc(&iwag);
if (error)
return error;
for_each_perag_from(mp, agno, pag) {
iwag.pag = pag;
error = xfs_iwalk_ag(&iwag);
if (error)
break;
iwag.startino = XFS_AGINO_TO_INO(mp, pag->pag_agno + 1, 0);
if (flags & XFS_INOBT_WALK_SAME_AG)
break;
iwag.pag = NULL;
}
if (iwag.pag)
xfs_perag_rele(pag);
xfs_iwalk_free(&iwag);
return error;
}
| linux-master | fs/xfs/xfs_iwalk.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_log_recover.h"
#include "xfs_trans_priv.h"
#include "xfs_alloc.h"
#include "xfs_ialloc.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_error.h"
#include "xfs_buf_item.h"
#include "xfs_ag.h"
#include "xfs_quota.h"
#include "xfs_reflink.h"
#define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
STATIC int
xlog_find_zeroed(
struct xlog *,
xfs_daddr_t *);
STATIC int
xlog_clear_stale_blocks(
struct xlog *,
xfs_lsn_t);
STATIC int
xlog_do_recovery_pass(
struct xlog *, xfs_daddr_t, xfs_daddr_t, int, xfs_daddr_t *);
/*
* Sector aligned buffer routines for buffer create/read/write/access
*/
/*
* Verify the log-relative block number and length in basic blocks are valid for
* an operation involving the given XFS log buffer. Returns true if the fields
* are valid, false otherwise.
*/
static inline bool
xlog_verify_bno(
struct xlog *log,
xfs_daddr_t blk_no,
int bbcount)
{
if (blk_no < 0 || blk_no >= log->l_logBBsize)
return false;
if (bbcount <= 0 || (blk_no + bbcount) > log->l_logBBsize)
return false;
return true;
}
/*
* Allocate a buffer to hold log data. The buffer needs to be able to map to
* a range of nbblks basic blocks at any valid offset within the log.
*/
static char *
xlog_alloc_buffer(
struct xlog *log,
int nbblks)
{
/*
* Pass log block 0 since we don't have an addr yet, buffer will be
* verified on read.
*/
if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, 0, nbblks))) {
xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
nbblks);
return NULL;
}
/*
* We do log I/O in units of log sectors (a power-of-2 multiple of the
* basic block size), so we round up the requested size to accommodate
* the basic blocks required for complete log sectors.
*
* In addition, the buffer may be used for a non-sector-aligned block
* offset, in which case an I/O of the requested size could extend
* beyond the end of the buffer. If the requested size is only 1 basic
* block it will never straddle a sector boundary, so this won't be an
* issue. Nor will this be a problem if the log I/O is done in basic
* blocks (sector size 1). But otherwise we extend the buffer by one
* extra log sector to ensure there's space to accommodate this
* possibility.
*/
if (nbblks > 1 && log->l_sectBBsize > 1)
nbblks += log->l_sectBBsize;
nbblks = round_up(nbblks, log->l_sectBBsize);
return kvzalloc(BBTOB(nbblks), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
}
/*
* Return the address of the start of the given block number's data
* in a log buffer. The buffer covers a log sector-aligned region.
*/
static inline unsigned int
xlog_align(
struct xlog *log,
xfs_daddr_t blk_no)
{
return BBTOB(blk_no & ((xfs_daddr_t)log->l_sectBBsize - 1));
}
static int
xlog_do_io(
struct xlog *log,
xfs_daddr_t blk_no,
unsigned int nbblks,
char *data,
enum req_op op)
{
int error;
if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, blk_no, nbblks))) {
xfs_warn(log->l_mp,
"Invalid log block/length (0x%llx, 0x%x) for buffer",
blk_no, nbblks);
return -EFSCORRUPTED;
}
blk_no = round_down(blk_no, log->l_sectBBsize);
nbblks = round_up(nbblks, log->l_sectBBsize);
ASSERT(nbblks > 0);
error = xfs_rw_bdev(log->l_targ->bt_bdev, log->l_logBBstart + blk_no,
BBTOB(nbblks), data, op);
if (error && !xlog_is_shutdown(log)) {
xfs_alert(log->l_mp,
"log recovery %s I/O error at daddr 0x%llx len %d error %d",
op == REQ_OP_WRITE ? "write" : "read",
blk_no, nbblks, error);
}
return error;
}
STATIC int
xlog_bread_noalign(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
char *data)
{
return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
}
STATIC int
xlog_bread(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
char *data,
char **offset)
{
int error;
error = xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
if (!error)
*offset = data + xlog_align(log, blk_no);
return error;
}
STATIC int
xlog_bwrite(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
char *data)
{
return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_WRITE);
}
#ifdef DEBUG
/*
* dump debug superblock and log record information
*/
STATIC void
xlog_header_check_dump(
xfs_mount_t *mp,
xlog_rec_header_t *head)
{
xfs_debug(mp, "%s: SB : uuid = %pU, fmt = %d",
__func__, &mp->m_sb.sb_uuid, XLOG_FMT);
xfs_debug(mp, " log : uuid = %pU, fmt = %d",
&head->h_fs_uuid, be32_to_cpu(head->h_fmt));
}
#else
#define xlog_header_check_dump(mp, head)
#endif
/*
* check log record header for recovery
*/
STATIC int
xlog_header_check_recover(
xfs_mount_t *mp,
xlog_rec_header_t *head)
{
ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
/*
* IRIX doesn't write the h_fmt field and leaves it zeroed
* (XLOG_FMT_UNKNOWN). This stops us from trying to recover
* a dirty log created in IRIX.
*/
if (XFS_IS_CORRUPT(mp, head->h_fmt != cpu_to_be32(XLOG_FMT))) {
xfs_warn(mp,
"dirty log written in incompatible format - can't recover");
xlog_header_check_dump(mp, head);
return -EFSCORRUPTED;
}
if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
&head->h_fs_uuid))) {
xfs_warn(mp,
"dirty log entry has mismatched uuid - can't recover");
xlog_header_check_dump(mp, head);
return -EFSCORRUPTED;
}
return 0;
}
/*
* read the head block of the log and check the header
*/
STATIC int
xlog_header_check_mount(
xfs_mount_t *mp,
xlog_rec_header_t *head)
{
ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
if (uuid_is_null(&head->h_fs_uuid)) {
/*
* IRIX doesn't write the h_fs_uuid or h_fmt fields. If
* h_fs_uuid is null, we assume this log was last mounted
* by IRIX and continue.
*/
xfs_warn(mp, "null uuid in log - IRIX style log");
} else if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
&head->h_fs_uuid))) {
xfs_warn(mp, "log has mismatched uuid - can't recover");
xlog_header_check_dump(mp, head);
return -EFSCORRUPTED;
}
return 0;
}
/*
* This routine finds (to an approximation) the first block in the physical
* log which contains the given cycle. It uses a binary search algorithm.
* Note that the algorithm can not be perfect because the disk will not
* necessarily be perfect.
*/
STATIC int
xlog_find_cycle_start(
struct xlog *log,
char *buffer,
xfs_daddr_t first_blk,
xfs_daddr_t *last_blk,
uint cycle)
{
char *offset;
xfs_daddr_t mid_blk;
xfs_daddr_t end_blk;
uint mid_cycle;
int error;
end_blk = *last_blk;
mid_blk = BLK_AVG(first_blk, end_blk);
while (mid_blk != first_blk && mid_blk != end_blk) {
error = xlog_bread(log, mid_blk, 1, buffer, &offset);
if (error)
return error;
mid_cycle = xlog_get_cycle(offset);
if (mid_cycle == cycle)
end_blk = mid_blk; /* last_half_cycle == mid_cycle */
else
first_blk = mid_blk; /* first_half_cycle == mid_cycle */
mid_blk = BLK_AVG(first_blk, end_blk);
}
ASSERT((mid_blk == first_blk && mid_blk+1 == end_blk) ||
(mid_blk == end_blk && mid_blk-1 == first_blk));
*last_blk = end_blk;
return 0;
}
/*
* Check that a range of blocks does not contain stop_on_cycle_no.
* Fill in *new_blk with the block offset where such a block is
* found, or with -1 (an invalid block number) if there is no such
* block in the range. The scan needs to occur from front to back
* and the pointer into the region must be updated since a later
* routine will need to perform another test.
*/
STATIC int
xlog_find_verify_cycle(
struct xlog *log,
xfs_daddr_t start_blk,
int nbblks,
uint stop_on_cycle_no,
xfs_daddr_t *new_blk)
{
xfs_daddr_t i, j;
uint cycle;
char *buffer;
xfs_daddr_t bufblks;
char *buf = NULL;
int error = 0;
/*
* Greedily allocate a buffer big enough to handle the full
* range of basic blocks we'll be examining. If that fails,
* try a smaller size. We need to be able to read at least
* a log sector, or we're out of luck.
*/
bufblks = roundup_pow_of_two(nbblks);
while (bufblks > log->l_logBBsize)
bufblks >>= 1;
while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
bufblks >>= 1;
if (bufblks < log->l_sectBBsize)
return -ENOMEM;
}
for (i = start_blk; i < start_blk + nbblks; i += bufblks) {
int bcount;
bcount = min(bufblks, (start_blk + nbblks - i));
error = xlog_bread(log, i, bcount, buffer, &buf);
if (error)
goto out;
for (j = 0; j < bcount; j++) {
cycle = xlog_get_cycle(buf);
if (cycle == stop_on_cycle_no) {
*new_blk = i+j;
goto out;
}
buf += BBSIZE;
}
}
*new_blk = -1;
out:
kmem_free(buffer);
return error;
}
static inline int
xlog_logrec_hblks(struct xlog *log, struct xlog_rec_header *rh)
{
if (xfs_has_logv2(log->l_mp)) {
int h_size = be32_to_cpu(rh->h_size);
if ((be32_to_cpu(rh->h_version) & XLOG_VERSION_2) &&
h_size > XLOG_HEADER_CYCLE_SIZE)
return DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
}
return 1;
}
/*
* Potentially backup over partial log record write.
*
* In the typical case, last_blk is the number of the block directly after
* a good log record. Therefore, we subtract one to get the block number
* of the last block in the given buffer. extra_bblks contains the number
* of blocks we would have read on a previous read. This happens when the
* last log record is split over the end of the physical log.
*
* extra_bblks is the number of blocks potentially verified on a previous
* call to this routine.
*/
STATIC int
xlog_find_verify_log_record(
struct xlog *log,
xfs_daddr_t start_blk,
xfs_daddr_t *last_blk,
int extra_bblks)
{
xfs_daddr_t i;
char *buffer;
char *offset = NULL;
xlog_rec_header_t *head = NULL;
int error = 0;
int smallmem = 0;
int num_blks = *last_blk - start_blk;
int xhdrs;
ASSERT(start_blk != 0 || *last_blk != start_blk);
buffer = xlog_alloc_buffer(log, num_blks);
if (!buffer) {
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
smallmem = 1;
} else {
error = xlog_bread(log, start_blk, num_blks, buffer, &offset);
if (error)
goto out;
offset += ((num_blks - 1) << BBSHIFT);
}
for (i = (*last_blk) - 1; i >= 0; i--) {
if (i < start_blk) {
/* valid log record not found */
xfs_warn(log->l_mp,
"Log inconsistent (didn't find previous header)");
ASSERT(0);
error = -EFSCORRUPTED;
goto out;
}
if (smallmem) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out;
}
head = (xlog_rec_header_t *)offset;
if (head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
break;
if (!smallmem)
offset -= BBSIZE;
}
/*
* We hit the beginning of the physical log & still no header. Return
* to caller. If caller can handle a return of -1, then this routine
* will be called again for the end of the physical log.
*/
if (i == -1) {
error = 1;
goto out;
}
/*
* We have the final block of the good log (the first block
* of the log record _before_ the head. So we check the uuid.
*/
if ((error = xlog_header_check_mount(log->l_mp, head)))
goto out;
/*
* We may have found a log record header before we expected one.
* last_blk will be the 1st block # with a given cycle #. We may end
* up reading an entire log record. In this case, we don't want to
* reset last_blk. Only when last_blk points in the middle of a log
* record do we update last_blk.
*/
xhdrs = xlog_logrec_hblks(log, head);
if (*last_blk - i + extra_bblks !=
BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
*last_blk = i;
out:
kmem_free(buffer);
return error;
}
/*
* Head is defined to be the point of the log where the next log write
* could go. This means that incomplete LR writes at the end are
* eliminated when calculating the head. We aren't guaranteed that previous
* LR have complete transactions. We only know that a cycle number of
* current cycle number -1 won't be present in the log if we start writing
* from our current block number.
*
* last_blk contains the block number of the first block with a given
* cycle number.
*
* Return: zero if normal, non-zero if error.
*/
STATIC int
xlog_find_head(
struct xlog *log,
xfs_daddr_t *return_head_blk)
{
char *buffer;
char *offset;
xfs_daddr_t new_blk, first_blk, start_blk, last_blk, head_blk;
int num_scan_bblks;
uint first_half_cycle, last_half_cycle;
uint stop_on_cycle;
int error, log_bbnum = log->l_logBBsize;
/* Is the end of the log device zeroed? */
error = xlog_find_zeroed(log, &first_blk);
if (error < 0) {
xfs_warn(log->l_mp, "empty log check failed");
return error;
}
if (error == 1) {
*return_head_blk = first_blk;
/* Is the whole lot zeroed? */
if (!first_blk) {
/* Linux XFS shouldn't generate totally zeroed logs -
* mkfs etc write a dummy unmount record to a fresh
* log so we can store the uuid in there
*/
xfs_warn(log->l_mp, "totally zeroed log");
}
return 0;
}
first_blk = 0; /* get cycle # of 1st block */
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
error = xlog_bread(log, 0, 1, buffer, &offset);
if (error)
goto out_free_buffer;
first_half_cycle = xlog_get_cycle(offset);
last_blk = head_blk = log_bbnum - 1; /* get cycle # of last block */
error = xlog_bread(log, last_blk, 1, buffer, &offset);
if (error)
goto out_free_buffer;
last_half_cycle = xlog_get_cycle(offset);
ASSERT(last_half_cycle != 0);
/*
* If the 1st half cycle number is equal to the last half cycle number,
* then the entire log is stamped with the same cycle number. In this
* case, head_blk can't be set to zero (which makes sense). The below
* math doesn't work out properly with head_blk equal to zero. Instead,
* we set it to log_bbnum which is an invalid block number, but this
* value makes the math correct. If head_blk doesn't changed through
* all the tests below, *head_blk is set to zero at the very end rather
* than log_bbnum. In a sense, log_bbnum and zero are the same block
* in a circular file.
*/
if (first_half_cycle == last_half_cycle) {
/*
* In this case we believe that the entire log should have
* cycle number last_half_cycle. We need to scan backwards
* from the end verifying that there are no holes still
* containing last_half_cycle - 1. If we find such a hole,
* then the start of that hole will be the new head. The
* simple case looks like
* x | x ... | x - 1 | x
* Another case that fits this picture would be
* x | x + 1 | x ... | x
* In this case the head really is somewhere at the end of the
* log, as one of the latest writes at the beginning was
* incomplete.
* One more case is
* x | x + 1 | x ... | x - 1 | x
* This is really the combination of the above two cases, and
* the head has to end up at the start of the x-1 hole at the
* end of the log.
*
* In the 256k log case, we will read from the beginning to the
* end of the log and search for cycle numbers equal to x-1.
* We don't worry about the x+1 blocks that we encounter,
* because we know that they cannot be the head since the log
* started with x.
*/
head_blk = log_bbnum;
stop_on_cycle = last_half_cycle - 1;
} else {
/*
* In this case we want to find the first block with cycle
* number matching last_half_cycle. We expect the log to be
* some variation on
* x + 1 ... | x ... | x
* The first block with cycle number x (last_half_cycle) will
* be where the new head belongs. First we do a binary search
* for the first occurrence of last_half_cycle. The binary
* search may not be totally accurate, so then we scan back
* from there looking for occurrences of last_half_cycle before
* us. If that backwards scan wraps around the beginning of
* the log, then we look for occurrences of last_half_cycle - 1
* at the end of the log. The cases we're looking for look
* like
* v binary search stopped here
* x + 1 ... | x | x + 1 | x ... | x
* ^ but we want to locate this spot
* or
* <---------> less than scan distance
* x + 1 ... | x ... | x - 1 | x
* ^ we want to locate this spot
*/
stop_on_cycle = last_half_cycle;
error = xlog_find_cycle_start(log, buffer, first_blk, &head_blk,
last_half_cycle);
if (error)
goto out_free_buffer;
}
/*
* Now validate the answer. Scan back some number of maximum possible
* blocks and make sure each one has the expected cycle number. The
* maximum is determined by the total possible amount of buffering
* in the in-core log. The following number can be made tighter if
* we actually look at the block size of the filesystem.
*/
num_scan_bblks = min_t(int, log_bbnum, XLOG_TOTAL_REC_SHIFT(log));
if (head_blk >= num_scan_bblks) {
/*
* We are guaranteed that the entire check can be performed
* in one buffer.
*/
start_blk = head_blk - num_scan_bblks;
if ((error = xlog_find_verify_cycle(log,
start_blk, num_scan_bblks,
stop_on_cycle, &new_blk)))
goto out_free_buffer;
if (new_blk != -1)
head_blk = new_blk;
} else { /* need to read 2 parts of log */
/*
* We are going to scan backwards in the log in two parts.
* First we scan the physical end of the log. In this part
* of the log, we are looking for blocks with cycle number
* last_half_cycle - 1.
* If we find one, then we know that the log starts there, as
* we've found a hole that didn't get written in going around
* the end of the physical log. The simple case for this is
* x + 1 ... | x ... | x - 1 | x
* <---------> less than scan distance
* If all of the blocks at the end of the log have cycle number
* last_half_cycle, then we check the blocks at the start of
* the log looking for occurrences of last_half_cycle. If we
* find one, then our current estimate for the location of the
* first occurrence of last_half_cycle is wrong and we move
* back to the hole we've found. This case looks like
* x + 1 ... | x | x + 1 | x ...
* ^ binary search stopped here
* Another case we need to handle that only occurs in 256k
* logs is
* x + 1 ... | x ... | x+1 | x ...
* ^ binary search stops here
* In a 256k log, the scan at the end of the log will see the
* x + 1 blocks. We need to skip past those since that is
* certainly not the head of the log. By searching for
* last_half_cycle-1 we accomplish that.
*/
ASSERT(head_blk <= INT_MAX &&
(xfs_daddr_t) num_scan_bblks >= head_blk);
start_blk = log_bbnum - (num_scan_bblks - head_blk);
if ((error = xlog_find_verify_cycle(log, start_blk,
num_scan_bblks - (int)head_blk,
(stop_on_cycle - 1), &new_blk)))
goto out_free_buffer;
if (new_blk != -1) {
head_blk = new_blk;
goto validate_head;
}
/*
* Scan beginning of log now. The last part of the physical
* log is good. This scan needs to verify that it doesn't find
* the last_half_cycle.
*/
start_blk = 0;
ASSERT(head_blk <= INT_MAX);
if ((error = xlog_find_verify_cycle(log,
start_blk, (int)head_blk,
stop_on_cycle, &new_blk)))
goto out_free_buffer;
if (new_blk != -1)
head_blk = new_blk;
}
validate_head:
/*
* Now we need to make sure head_blk is not pointing to a block in
* the middle of a log record.
*/
num_scan_bblks = XLOG_REC_SHIFT(log);
if (head_blk >= num_scan_bblks) {
start_blk = head_blk - num_scan_bblks; /* don't read head_blk */
/* start ptr at last block ptr before head_blk */
error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
if (error == 1)
error = -EIO;
if (error)
goto out_free_buffer;
} else {
start_blk = 0;
ASSERT(head_blk <= INT_MAX);
error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
if (error < 0)
goto out_free_buffer;
if (error == 1) {
/* We hit the beginning of the log during our search */
start_blk = log_bbnum - (num_scan_bblks - head_blk);
new_blk = log_bbnum;
ASSERT(start_blk <= INT_MAX &&
(xfs_daddr_t) log_bbnum-start_blk >= 0);
ASSERT(head_blk <= INT_MAX);
error = xlog_find_verify_log_record(log, start_blk,
&new_blk, (int)head_blk);
if (error == 1)
error = -EIO;
if (error)
goto out_free_buffer;
if (new_blk != log_bbnum)
head_blk = new_blk;
} else if (error)
goto out_free_buffer;
}
kmem_free(buffer);
if (head_blk == log_bbnum)
*return_head_blk = 0;
else
*return_head_blk = head_blk;
/*
* When returning here, we have a good block number. Bad block
* means that during a previous crash, we didn't have a clean break
* from cycle number N to cycle number N-1. In this case, we need
* to find the first block with cycle number N-1.
*/
return 0;
out_free_buffer:
kmem_free(buffer);
if (error)
xfs_warn(log->l_mp, "failed to find log head");
return error;
}
/*
* Seek backwards in the log for log record headers.
*
* Given a starting log block, walk backwards until we find the provided number
* of records or hit the provided tail block. The return value is the number of
* records encountered or a negative error code. The log block and buffer
* pointer of the last record seen are returned in rblk and rhead respectively.
*/
STATIC int
xlog_rseek_logrec_hdr(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk,
int count,
char *buffer,
xfs_daddr_t *rblk,
struct xlog_rec_header **rhead,
bool *wrapped)
{
int i;
int error;
int found = 0;
char *offset = NULL;
xfs_daddr_t end_blk;
*wrapped = false;
/*
* Walk backwards from the head block until we hit the tail or the first
* block in the log.
*/
end_blk = head_blk > tail_blk ? tail_blk : 0;
for (i = (int) head_blk - 1; i >= end_blk; i--) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
/*
* If we haven't hit the tail block or the log record header count,
* start looking again from the end of the physical log. Note that
* callers can pass head == tail if the tail is not yet known.
*/
if (tail_blk >= head_blk && found != count) {
for (i = log->l_logBBsize - 1; i >= (int) tail_blk; i--) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *)offset ==
cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*wrapped = true;
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
}
return found;
out_error:
return error;
}
/*
* Seek forward in the log for log record headers.
*
* Given head and tail blocks, walk forward from the tail block until we find
* the provided number of records or hit the head block. The return value is the
* number of records encountered or a negative error code. The log block and
* buffer pointer of the last record seen are returned in rblk and rhead
* respectively.
*/
STATIC int
xlog_seek_logrec_hdr(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk,
int count,
char *buffer,
xfs_daddr_t *rblk,
struct xlog_rec_header **rhead,
bool *wrapped)
{
int i;
int error;
int found = 0;
char *offset = NULL;
xfs_daddr_t end_blk;
*wrapped = false;
/*
* Walk forward from the tail block until we hit the head or the last
* block in the log.
*/
end_blk = head_blk > tail_blk ? head_blk : log->l_logBBsize - 1;
for (i = (int) tail_blk; i <= end_blk; i++) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
/*
* If we haven't hit the head block or the log record header count,
* start looking again from the start of the physical log.
*/
if (tail_blk > head_blk && found != count) {
for (i = 0; i < (int) head_blk; i++) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *)offset ==
cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*wrapped = true;
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
}
return found;
out_error:
return error;
}
/*
* Calculate distance from head to tail (i.e., unused space in the log).
*/
static inline int
xlog_tail_distance(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk)
{
if (head_blk < tail_blk)
return tail_blk - head_blk;
return tail_blk + (log->l_logBBsize - head_blk);
}
/*
* Verify the log tail. This is particularly important when torn or incomplete
* writes have been detected near the front of the log and the head has been
* walked back accordingly.
*
* We also have to handle the case where the tail was pinned and the head
* blocked behind the tail right before a crash. If the tail had been pushed
* immediately prior to the crash and the subsequent checkpoint was only
* partially written, it's possible it overwrote the last referenced tail in the
* log with garbage. This is not a coherency problem because the tail must have
* been pushed before it can be overwritten, but appears as log corruption to
* recovery because we have no way to know the tail was updated if the
* subsequent checkpoint didn't write successfully.
*
* Therefore, CRC check the log from tail to head. If a failure occurs and the
* offending record is within max iclog bufs from the head, walk the tail
* forward and retry until a valid tail is found or corruption is detected out
* of the range of a possible overwrite.
*/
STATIC int
xlog_verify_tail(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t *tail_blk,
int hsize)
{
struct xlog_rec_header *thead;
char *buffer;
xfs_daddr_t first_bad;
int error = 0;
bool wrapped;
xfs_daddr_t tmp_tail;
xfs_daddr_t orig_tail = *tail_blk;
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
/*
* Make sure the tail points to a record (returns positive count on
* success).
*/
error = xlog_seek_logrec_hdr(log, head_blk, *tail_blk, 1, buffer,
&tmp_tail, &thead, &wrapped);
if (error < 0)
goto out;
if (*tail_blk != tmp_tail)
*tail_blk = tmp_tail;
/*
* Run a CRC check from the tail to the head. We can't just check
* MAX_ICLOGS records past the tail because the tail may point to stale
* blocks cleared during the search for the head/tail. These blocks are
* overwritten with zero-length records and thus record count is not a
* reliable indicator of the iclog state before a crash.
*/
first_bad = 0;
error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
XLOG_RECOVER_CRCPASS, &first_bad);
while ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
int tail_distance;
/*
* Is corruption within range of the head? If so, retry from
* the next record. Otherwise return an error.
*/
tail_distance = xlog_tail_distance(log, head_blk, first_bad);
if (tail_distance > BTOBB(XLOG_MAX_ICLOGS * hsize))
break;
/* skip to the next record; returns positive count on success */
error = xlog_seek_logrec_hdr(log, head_blk, first_bad, 2,
buffer, &tmp_tail, &thead, &wrapped);
if (error < 0)
goto out;
*tail_blk = tmp_tail;
first_bad = 0;
error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
XLOG_RECOVER_CRCPASS, &first_bad);
}
if (!error && *tail_blk != orig_tail)
xfs_warn(log->l_mp,
"Tail block (0x%llx) overwrite detected. Updated to 0x%llx",
orig_tail, *tail_blk);
out:
kmem_free(buffer);
return error;
}
/*
* Detect and trim torn writes from the head of the log.
*
* Storage without sector atomicity guarantees can result in torn writes in the
* log in the event of a crash. Our only means to detect this scenario is via
* CRC verification. While we can't always be certain that CRC verification
* failure is due to a torn write vs. an unrelated corruption, we do know that
* only a certain number (XLOG_MAX_ICLOGS) of log records can be written out at
* one time. Therefore, CRC verify up to XLOG_MAX_ICLOGS records at the head of
* the log and treat failures in this range as torn writes as a matter of
* policy. In the event of CRC failure, the head is walked back to the last good
* record in the log and the tail is updated from that record and verified.
*/
STATIC int
xlog_verify_head(
struct xlog *log,
xfs_daddr_t *head_blk, /* in/out: unverified head */
xfs_daddr_t *tail_blk, /* out: tail block */
char *buffer,
xfs_daddr_t *rhead_blk, /* start blk of last record */
struct xlog_rec_header **rhead, /* ptr to last record */
bool *wrapped) /* last rec. wraps phys. log */
{
struct xlog_rec_header *tmp_rhead;
char *tmp_buffer;
xfs_daddr_t first_bad;
xfs_daddr_t tmp_rhead_blk;
int found;
int error;
bool tmp_wrapped;
/*
* Check the head of the log for torn writes. Search backwards from the
* head until we hit the tail or the maximum number of log record I/Os
* that could have been in flight at one time. Use a temporary buffer so
* we don't trash the rhead/buffer pointers from the caller.
*/
tmp_buffer = xlog_alloc_buffer(log, 1);
if (!tmp_buffer)
return -ENOMEM;
error = xlog_rseek_logrec_hdr(log, *head_blk, *tail_blk,
XLOG_MAX_ICLOGS, tmp_buffer,
&tmp_rhead_blk, &tmp_rhead, &tmp_wrapped);
kmem_free(tmp_buffer);
if (error < 0)
return error;
/*
* Now run a CRC verification pass over the records starting at the
* block found above to the current head. If a CRC failure occurs, the
* log block of the first bad record is saved in first_bad.
*/
error = xlog_do_recovery_pass(log, *head_blk, tmp_rhead_blk,
XLOG_RECOVER_CRCPASS, &first_bad);
if ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
/*
* We've hit a potential torn write. Reset the error and warn
* about it.
*/
error = 0;
xfs_warn(log->l_mp,
"Torn write (CRC failure) detected at log block 0x%llx. Truncating head block from 0x%llx.",
first_bad, *head_blk);
/*
* Get the header block and buffer pointer for the last good
* record before the bad record.
*
* Note that xlog_find_tail() clears the blocks at the new head
* (i.e., the records with invalid CRC) if the cycle number
* matches the current cycle.
*/
found = xlog_rseek_logrec_hdr(log, first_bad, *tail_blk, 1,
buffer, rhead_blk, rhead, wrapped);
if (found < 0)
return found;
if (found == 0) /* XXX: right thing to do here? */
return -EIO;
/*
* Reset the head block to the starting block of the first bad
* log record and set the tail block based on the last good
* record.
*
* Bail out if the updated head/tail match as this indicates
* possible corruption outside of the acceptable
* (XLOG_MAX_ICLOGS) range. This is a job for xfs_repair...
*/
*head_blk = first_bad;
*tail_blk = BLOCK_LSN(be64_to_cpu((*rhead)->h_tail_lsn));
if (*head_blk == *tail_blk) {
ASSERT(0);
return 0;
}
}
if (error)
return error;
return xlog_verify_tail(log, *head_blk, tail_blk,
be32_to_cpu((*rhead)->h_size));
}
/*
* We need to make sure we handle log wrapping properly, so we can't use the
* calculated logbno directly. Make sure it wraps to the correct bno inside the
* log.
*
* The log is limited to 32 bit sizes, so we use the appropriate modulus
* operation here and cast it back to a 64 bit daddr on return.
*/
static inline xfs_daddr_t
xlog_wrap_logbno(
struct xlog *log,
xfs_daddr_t bno)
{
int mod;
div_s64_rem(bno, log->l_logBBsize, &mod);
return mod;
}
/*
* Check whether the head of the log points to an unmount record. In other
* words, determine whether the log is clean. If so, update the in-core state
* appropriately.
*/
static int
xlog_check_unmount_rec(
struct xlog *log,
xfs_daddr_t *head_blk,
xfs_daddr_t *tail_blk,
struct xlog_rec_header *rhead,
xfs_daddr_t rhead_blk,
char *buffer,
bool *clean)
{
struct xlog_op_header *op_head;
xfs_daddr_t umount_data_blk;
xfs_daddr_t after_umount_blk;
int hblks;
int error;
char *offset;
*clean = false;
/*
* Look for unmount record. If we find it, then we know there was a
* clean unmount. Since 'i' could be the last block in the physical
* log, we convert to a log block before comparing to the head_blk.
*
* Save the current tail lsn to use to pass to xlog_clear_stale_blocks()
* below. We won't want to clear the unmount record if there is one, so
* we pass the lsn of the unmount record rather than the block after it.
*/
hblks = xlog_logrec_hblks(log, rhead);
after_umount_blk = xlog_wrap_logbno(log,
rhead_blk + hblks + BTOBB(be32_to_cpu(rhead->h_len)));
if (*head_blk == after_umount_blk &&
be32_to_cpu(rhead->h_num_logops) == 1) {
umount_data_blk = xlog_wrap_logbno(log, rhead_blk + hblks);
error = xlog_bread(log, umount_data_blk, 1, buffer, &offset);
if (error)
return error;
op_head = (struct xlog_op_header *)offset;
if (op_head->oh_flags & XLOG_UNMOUNT_TRANS) {
/*
* Set tail and last sync so that newly written log
* records will point recovery to after the current
* unmount record.
*/
xlog_assign_atomic_lsn(&log->l_tail_lsn,
log->l_curr_cycle, after_umount_blk);
xlog_assign_atomic_lsn(&log->l_last_sync_lsn,
log->l_curr_cycle, after_umount_blk);
*tail_blk = after_umount_blk;
*clean = true;
}
}
return 0;
}
static void
xlog_set_state(
struct xlog *log,
xfs_daddr_t head_blk,
struct xlog_rec_header *rhead,
xfs_daddr_t rhead_blk,
bool bump_cycle)
{
/*
* Reset log values according to the state of the log when we
* crashed. In the case where head_blk == 0, we bump curr_cycle
* one because the next write starts a new cycle rather than
* continuing the cycle of the last good log record. At this
* point we have guaranteed that all partial log records have been
* accounted for. Therefore, we know that the last good log record
* written was complete and ended exactly on the end boundary
* of the physical log.
*/
log->l_prev_block = rhead_blk;
log->l_curr_block = (int)head_blk;
log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
if (bump_cycle)
log->l_curr_cycle++;
atomic64_set(&log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
atomic64_set(&log->l_last_sync_lsn, be64_to_cpu(rhead->h_lsn));
xlog_assign_grant_head(&log->l_reserve_head.grant, log->l_curr_cycle,
BBTOB(log->l_curr_block));
xlog_assign_grant_head(&log->l_write_head.grant, log->l_curr_cycle,
BBTOB(log->l_curr_block));
}
/*
* Find the sync block number or the tail of the log.
*
* This will be the block number of the last record to have its
* associated buffers synced to disk. Every log record header has
* a sync lsn embedded in it. LSNs hold block numbers, so it is easy
* to get a sync block number. The only concern is to figure out which
* log record header to believe.
*
* The following algorithm uses the log record header with the largest
* lsn. The entire log record does not need to be valid. We only care
* that the header is valid.
*
* We could speed up search by using current head_blk buffer, but it is not
* available.
*/
STATIC int
xlog_find_tail(
struct xlog *log,
xfs_daddr_t *head_blk,
xfs_daddr_t *tail_blk)
{
xlog_rec_header_t *rhead;
char *offset = NULL;
char *buffer;
int error;
xfs_daddr_t rhead_blk;
xfs_lsn_t tail_lsn;
bool wrapped = false;
bool clean = false;
/*
* Find previous log record
*/
if ((error = xlog_find_head(log, head_blk)))
return error;
ASSERT(*head_blk < INT_MAX);
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
if (*head_blk == 0) { /* special case */
error = xlog_bread(log, 0, 1, buffer, &offset);
if (error)
goto done;
if (xlog_get_cycle(offset) == 0) {
*tail_blk = 0;
/* leave all other log inited values alone */
goto done;
}
}
/*
* Search backwards through the log looking for the log record header
* block. This wraps all the way back around to the head so something is
* seriously wrong if we can't find it.
*/
error = xlog_rseek_logrec_hdr(log, *head_blk, *head_blk, 1, buffer,
&rhead_blk, &rhead, &wrapped);
if (error < 0)
goto done;
if (!error) {
xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
error = -EFSCORRUPTED;
goto done;
}
*tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
/*
* Set the log state based on the current head record.
*/
xlog_set_state(log, *head_blk, rhead, rhead_blk, wrapped);
tail_lsn = atomic64_read(&log->l_tail_lsn);
/*
* Look for an unmount record at the head of the log. This sets the log
* state to determine whether recovery is necessary.
*/
error = xlog_check_unmount_rec(log, head_blk, tail_blk, rhead,
rhead_blk, buffer, &clean);
if (error)
goto done;
/*
* Verify the log head if the log is not clean (e.g., we have anything
* but an unmount record at the head). This uses CRC verification to
* detect and trim torn writes. If discovered, CRC failures are
* considered torn writes and the log head is trimmed accordingly.
*
* Note that we can only run CRC verification when the log is dirty
* because there's no guarantee that the log data behind an unmount
* record is compatible with the current architecture.
*/
if (!clean) {
xfs_daddr_t orig_head = *head_blk;
error = xlog_verify_head(log, head_blk, tail_blk, buffer,
&rhead_blk, &rhead, &wrapped);
if (error)
goto done;
/* update in-core state again if the head changed */
if (*head_blk != orig_head) {
xlog_set_state(log, *head_blk, rhead, rhead_blk,
wrapped);
tail_lsn = atomic64_read(&log->l_tail_lsn);
error = xlog_check_unmount_rec(log, head_blk, tail_blk,
rhead, rhead_blk, buffer,
&clean);
if (error)
goto done;
}
}
/*
* Note that the unmount was clean. If the unmount was not clean, we
* need to know this to rebuild the superblock counters from the perag
* headers if we have a filesystem using non-persistent counters.
*/
if (clean)
set_bit(XFS_OPSTATE_CLEAN, &log->l_mp->m_opstate);
/*
* Make sure that there are no blocks in front of the head
* with the same cycle number as the head. This can happen
* because we allow multiple outstanding log writes concurrently,
* and the later writes might make it out before earlier ones.
*
* We use the lsn from before modifying it so that we'll never
* overwrite the unmount record after a clean unmount.
*
* Do this only if we are going to recover the filesystem
*
* NOTE: This used to say "if (!readonly)"
* However on Linux, we can & do recover a read-only filesystem.
* We only skip recovery if NORECOVERY is specified on mount,
* in which case we would not be here.
*
* But... if the -device- itself is readonly, just skip this.
* We can't recover this device anyway, so it won't matter.
*/
if (!xfs_readonly_buftarg(log->l_targ))
error = xlog_clear_stale_blocks(log, tail_lsn);
done:
kmem_free(buffer);
if (error)
xfs_warn(log->l_mp, "failed to locate log tail");
return error;
}
/*
* Is the log zeroed at all?
*
* The last binary search should be changed to perform an X block read
* once X becomes small enough. You can then search linearly through
* the X blocks. This will cut down on the number of reads we need to do.
*
* If the log is partially zeroed, this routine will pass back the blkno
* of the first block with cycle number 0. It won't have a complete LR
* preceding it.
*
* Return:
* 0 => the log is completely written to
* 1 => use *blk_no as the first block of the log
* <0 => error has occurred
*/
STATIC int
xlog_find_zeroed(
struct xlog *log,
xfs_daddr_t *blk_no)
{
char *buffer;
char *offset;
uint first_cycle, last_cycle;
xfs_daddr_t new_blk, last_blk, start_blk;
xfs_daddr_t num_scan_bblks;
int error, log_bbnum = log->l_logBBsize;
*blk_no = 0;
/* check totally zeroed log */
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
error = xlog_bread(log, 0, 1, buffer, &offset);
if (error)
goto out_free_buffer;
first_cycle = xlog_get_cycle(offset);
if (first_cycle == 0) { /* completely zeroed log */
*blk_no = 0;
kmem_free(buffer);
return 1;
}
/* check partially zeroed log */
error = xlog_bread(log, log_bbnum-1, 1, buffer, &offset);
if (error)
goto out_free_buffer;
last_cycle = xlog_get_cycle(offset);
if (last_cycle != 0) { /* log completely written to */
kmem_free(buffer);
return 0;
}
/* we have a partially zeroed log */
last_blk = log_bbnum-1;
error = xlog_find_cycle_start(log, buffer, 0, &last_blk, 0);
if (error)
goto out_free_buffer;
/*
* Validate the answer. Because there is no way to guarantee that
* the entire log is made up of log records which are the same size,
* we scan over the defined maximum blocks. At this point, the maximum
* is not chosen to mean anything special. XXXmiken
*/
num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
ASSERT(num_scan_bblks <= INT_MAX);
if (last_blk < num_scan_bblks)
num_scan_bblks = last_blk;
start_blk = last_blk - num_scan_bblks;
/*
* We search for any instances of cycle number 0 that occur before
* our current estimate of the head. What we're trying to detect is
* 1 ... | 0 | 1 | 0...
* ^ binary search ends here
*/
if ((error = xlog_find_verify_cycle(log, start_blk,
(int)num_scan_bblks, 0, &new_blk)))
goto out_free_buffer;
if (new_blk != -1)
last_blk = new_blk;
/*
* Potentially backup over partial log record write. We don't need
* to search the end of the log because we know it is zero.
*/
error = xlog_find_verify_log_record(log, start_blk, &last_blk, 0);
if (error == 1)
error = -EIO;
if (error)
goto out_free_buffer;
*blk_no = last_blk;
out_free_buffer:
kmem_free(buffer);
if (error)
return error;
return 1;
}
/*
* These are simple subroutines used by xlog_clear_stale_blocks() below
* to initialize a buffer full of empty log record headers and write
* them into the log.
*/
STATIC void
xlog_add_record(
struct xlog *log,
char *buf,
int cycle,
int block,
int tail_cycle,
int tail_block)
{
xlog_rec_header_t *recp = (xlog_rec_header_t *)buf;
memset(buf, 0, BBSIZE);
recp->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
recp->h_cycle = cpu_to_be32(cycle);
recp->h_version = cpu_to_be32(
xfs_has_logv2(log->l_mp) ? 2 : 1);
recp->h_lsn = cpu_to_be64(xlog_assign_lsn(cycle, block));
recp->h_tail_lsn = cpu_to_be64(xlog_assign_lsn(tail_cycle, tail_block));
recp->h_fmt = cpu_to_be32(XLOG_FMT);
memcpy(&recp->h_fs_uuid, &log->l_mp->m_sb.sb_uuid, sizeof(uuid_t));
}
STATIC int
xlog_write_log_records(
struct xlog *log,
int cycle,
int start_block,
int blocks,
int tail_cycle,
int tail_block)
{
char *offset;
char *buffer;
int balign, ealign;
int sectbb = log->l_sectBBsize;
int end_block = start_block + blocks;
int bufblks;
int error = 0;
int i, j = 0;
/*
* Greedily allocate a buffer big enough to handle the full
* range of basic blocks to be written. If that fails, try
* a smaller size. We need to be able to write at least a
* log sector, or we're out of luck.
*/
bufblks = roundup_pow_of_two(blocks);
while (bufblks > log->l_logBBsize)
bufblks >>= 1;
while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
bufblks >>= 1;
if (bufblks < sectbb)
return -ENOMEM;
}
/* We may need to do a read at the start to fill in part of
* the buffer in the starting sector not covered by the first
* write below.
*/
balign = round_down(start_block, sectbb);
if (balign != start_block) {
error = xlog_bread_noalign(log, start_block, 1, buffer);
if (error)
goto out_free_buffer;
j = start_block - balign;
}
for (i = start_block; i < end_block; i += bufblks) {
int bcount, endcount;
bcount = min(bufblks, end_block - start_block);
endcount = bcount - j;
/* We may need to do a read at the end to fill in part of
* the buffer in the final sector not covered by the write.
* If this is the same sector as the above read, skip it.
*/
ealign = round_down(end_block, sectbb);
if (j == 0 && (start_block + endcount > ealign)) {
error = xlog_bread_noalign(log, ealign, sectbb,
buffer + BBTOB(ealign - start_block));
if (error)
break;
}
offset = buffer + xlog_align(log, start_block);
for (; j < endcount; j++) {
xlog_add_record(log, offset, cycle, i+j,
tail_cycle, tail_block);
offset += BBSIZE;
}
error = xlog_bwrite(log, start_block, endcount, buffer);
if (error)
break;
start_block += endcount;
j = 0;
}
out_free_buffer:
kmem_free(buffer);
return error;
}
/*
* This routine is called to blow away any incomplete log writes out
* in front of the log head. We do this so that we won't become confused
* if we come up, write only a little bit more, and then crash again.
* If we leave the partial log records out there, this situation could
* cause us to think those partial writes are valid blocks since they
* have the current cycle number. We get rid of them by overwriting them
* with empty log records with the old cycle number rather than the
* current one.
*
* The tail lsn is passed in rather than taken from
* the log so that we will not write over the unmount record after a
* clean unmount in a 512 block log. Doing so would leave the log without
* any valid log records in it until a new one was written. If we crashed
* during that time we would not be able to recover.
*/
STATIC int
xlog_clear_stale_blocks(
struct xlog *log,
xfs_lsn_t tail_lsn)
{
int tail_cycle, head_cycle;
int tail_block, head_block;
int tail_distance, max_distance;
int distance;
int error;
tail_cycle = CYCLE_LSN(tail_lsn);
tail_block = BLOCK_LSN(tail_lsn);
head_cycle = log->l_curr_cycle;
head_block = log->l_curr_block;
/*
* Figure out the distance between the new head of the log
* and the tail. We want to write over any blocks beyond the
* head that we may have written just before the crash, but
* we don't want to overwrite the tail of the log.
*/
if (head_cycle == tail_cycle) {
/*
* The tail is behind the head in the physical log,
* so the distance from the head to the tail is the
* distance from the head to the end of the log plus
* the distance from the beginning of the log to the
* tail.
*/
if (XFS_IS_CORRUPT(log->l_mp,
head_block < tail_block ||
head_block >= log->l_logBBsize))
return -EFSCORRUPTED;
tail_distance = tail_block + (log->l_logBBsize - head_block);
} else {
/*
* The head is behind the tail in the physical log,
* so the distance from the head to the tail is just
* the tail block minus the head block.
*/
if (XFS_IS_CORRUPT(log->l_mp,
head_block >= tail_block ||
head_cycle != tail_cycle + 1))
return -EFSCORRUPTED;
tail_distance = tail_block - head_block;
}
/*
* If the head is right up against the tail, we can't clear
* anything.
*/
if (tail_distance <= 0) {
ASSERT(tail_distance == 0);
return 0;
}
max_distance = XLOG_TOTAL_REC_SHIFT(log);
/*
* Take the smaller of the maximum amount of outstanding I/O
* we could have and the distance to the tail to clear out.
* We take the smaller so that we don't overwrite the tail and
* we don't waste all day writing from the head to the tail
* for no reason.
*/
max_distance = min(max_distance, tail_distance);
if ((head_block + max_distance) <= log->l_logBBsize) {
/*
* We can stomp all the blocks we need to without
* wrapping around the end of the log. Just do it
* in a single write. Use the cycle number of the
* current cycle minus one so that the log will look like:
* n ... | n - 1 ...
*/
error = xlog_write_log_records(log, (head_cycle - 1),
head_block, max_distance, tail_cycle,
tail_block);
if (error)
return error;
} else {
/*
* We need to wrap around the end of the physical log in
* order to clear all the blocks. Do it in two separate
* I/Os. The first write should be from the head to the
* end of the physical log, and it should use the current
* cycle number minus one just like above.
*/
distance = log->l_logBBsize - head_block;
error = xlog_write_log_records(log, (head_cycle - 1),
head_block, distance, tail_cycle,
tail_block);
if (error)
return error;
/*
* Now write the blocks at the start of the physical log.
* This writes the remainder of the blocks we want to clear.
* It uses the current cycle number since we're now on the
* same cycle as the head so that we get:
* n ... n ... | n - 1 ...
* ^^^^^ blocks we're writing
*/
distance = max_distance - (log->l_logBBsize - head_block);
error = xlog_write_log_records(log, head_cycle, 0, distance,
tail_cycle, tail_block);
if (error)
return error;
}
return 0;
}
/*
* Release the recovered intent item in the AIL that matches the given intent
* type and intent id.
*/
void
xlog_recover_release_intent(
struct xlog *log,
unsigned short intent_type,
uint64_t intent_id)
{
struct xfs_ail_cursor cur;
struct xfs_log_item *lip;
struct xfs_ail *ailp = log->l_ailp;
spin_lock(&ailp->ail_lock);
for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0); lip != NULL;
lip = xfs_trans_ail_cursor_next(ailp, &cur)) {
if (lip->li_type != intent_type)
continue;
if (!lip->li_ops->iop_match(lip, intent_id))
continue;
spin_unlock(&ailp->ail_lock);
lip->li_ops->iop_release(lip);
spin_lock(&ailp->ail_lock);
break;
}
xfs_trans_ail_cursor_done(&cur);
spin_unlock(&ailp->ail_lock);
}
int
xlog_recover_iget(
struct xfs_mount *mp,
xfs_ino_t ino,
struct xfs_inode **ipp)
{
int error;
error = xfs_iget(mp, NULL, ino, 0, 0, ipp);
if (error)
return error;
error = xfs_qm_dqattach(*ipp);
if (error) {
xfs_irele(*ipp);
return error;
}
if (VFS_I(*ipp)->i_nlink == 0)
xfs_iflags_set(*ipp, XFS_IRECOVERY);
return 0;
}
/******************************************************************************
*
* Log recover routines
*
******************************************************************************
*/
static const struct xlog_recover_item_ops *xlog_recover_item_ops[] = {
&xlog_buf_item_ops,
&xlog_inode_item_ops,
&xlog_dquot_item_ops,
&xlog_quotaoff_item_ops,
&xlog_icreate_item_ops,
&xlog_efi_item_ops,
&xlog_efd_item_ops,
&xlog_rui_item_ops,
&xlog_rud_item_ops,
&xlog_cui_item_ops,
&xlog_cud_item_ops,
&xlog_bui_item_ops,
&xlog_bud_item_ops,
&xlog_attri_item_ops,
&xlog_attrd_item_ops,
};
static const struct xlog_recover_item_ops *
xlog_find_item_ops(
struct xlog_recover_item *item)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(xlog_recover_item_ops); i++)
if (ITEM_TYPE(item) == xlog_recover_item_ops[i]->item_type)
return xlog_recover_item_ops[i];
return NULL;
}
/*
* Sort the log items in the transaction.
*
* The ordering constraints are defined by the inode allocation and unlink
* behaviour. The rules are:
*
* 1. Every item is only logged once in a given transaction. Hence it
* represents the last logged state of the item. Hence ordering is
* dependent on the order in which operations need to be performed so
* required initial conditions are always met.
*
* 2. Cancelled buffers are recorded in pass 1 in a separate table and
* there's nothing to replay from them so we can simply cull them
* from the transaction. However, we can't do that until after we've
* replayed all the other items because they may be dependent on the
* cancelled buffer and replaying the cancelled buffer can remove it
* form the cancelled buffer table. Hence they have tobe done last.
*
* 3. Inode allocation buffers must be replayed before inode items that
* read the buffer and replay changes into it. For filesystems using the
* ICREATE transactions, this means XFS_LI_ICREATE objects need to get
* treated the same as inode allocation buffers as they create and
* initialise the buffers directly.
*
* 4. Inode unlink buffers must be replayed after inode items are replayed.
* This ensures that inodes are completely flushed to the inode buffer
* in a "free" state before we remove the unlinked inode list pointer.
*
* Hence the ordering needs to be inode allocation buffers first, inode items
* second, inode unlink buffers third and cancelled buffers last.
*
* But there's a problem with that - we can't tell an inode allocation buffer
* apart from a regular buffer, so we can't separate them. We can, however,
* tell an inode unlink buffer from the others, and so we can separate them out
* from all the other buffers and move them to last.
*
* Hence, 4 lists, in order from head to tail:
* - buffer_list for all buffers except cancelled/inode unlink buffers
* - item_list for all non-buffer items
* - inode_buffer_list for inode unlink buffers
* - cancel_list for the cancelled buffers
*
* Note that we add objects to the tail of the lists so that first-to-last
* ordering is preserved within the lists. Adding objects to the head of the
* list means when we traverse from the head we walk them in last-to-first
* order. For cancelled buffers and inode unlink buffers this doesn't matter,
* but for all other items there may be specific ordering that we need to
* preserve.
*/
STATIC int
xlog_recover_reorder_trans(
struct xlog *log,
struct xlog_recover *trans,
int pass)
{
struct xlog_recover_item *item, *n;
int error = 0;
LIST_HEAD(sort_list);
LIST_HEAD(cancel_list);
LIST_HEAD(buffer_list);
LIST_HEAD(inode_buffer_list);
LIST_HEAD(item_list);
list_splice_init(&trans->r_itemq, &sort_list);
list_for_each_entry_safe(item, n, &sort_list, ri_list) {
enum xlog_recover_reorder fate = XLOG_REORDER_ITEM_LIST;
item->ri_ops = xlog_find_item_ops(item);
if (!item->ri_ops) {
xfs_warn(log->l_mp,
"%s: unrecognized type of log operation (%d)",
__func__, ITEM_TYPE(item));
ASSERT(0);
/*
* return the remaining items back to the transaction
* item list so they can be freed in caller.
*/
if (!list_empty(&sort_list))
list_splice_init(&sort_list, &trans->r_itemq);
error = -EFSCORRUPTED;
break;
}
if (item->ri_ops->reorder)
fate = item->ri_ops->reorder(item);
switch (fate) {
case XLOG_REORDER_BUFFER_LIST:
list_move_tail(&item->ri_list, &buffer_list);
break;
case XLOG_REORDER_CANCEL_LIST:
trace_xfs_log_recover_item_reorder_head(log,
trans, item, pass);
list_move(&item->ri_list, &cancel_list);
break;
case XLOG_REORDER_INODE_BUFFER_LIST:
list_move(&item->ri_list, &inode_buffer_list);
break;
case XLOG_REORDER_ITEM_LIST:
trace_xfs_log_recover_item_reorder_tail(log,
trans, item, pass);
list_move_tail(&item->ri_list, &item_list);
break;
}
}
ASSERT(list_empty(&sort_list));
if (!list_empty(&buffer_list))
list_splice(&buffer_list, &trans->r_itemq);
if (!list_empty(&item_list))
list_splice_tail(&item_list, &trans->r_itemq);
if (!list_empty(&inode_buffer_list))
list_splice_tail(&inode_buffer_list, &trans->r_itemq);
if (!list_empty(&cancel_list))
list_splice_tail(&cancel_list, &trans->r_itemq);
return error;
}
void
xlog_buf_readahead(
struct xlog *log,
xfs_daddr_t blkno,
uint len,
const struct xfs_buf_ops *ops)
{
if (!xlog_is_buffer_cancelled(log, blkno, len))
xfs_buf_readahead(log->l_mp->m_ddev_targp, blkno, len, ops);
}
STATIC int
xlog_recover_items_pass2(
struct xlog *log,
struct xlog_recover *trans,
struct list_head *buffer_list,
struct list_head *item_list)
{
struct xlog_recover_item *item;
int error = 0;
list_for_each_entry(item, item_list, ri_list) {
trace_xfs_log_recover_item_recover(log, trans, item,
XLOG_RECOVER_PASS2);
if (item->ri_ops->commit_pass2)
error = item->ri_ops->commit_pass2(log, buffer_list,
item, trans->r_lsn);
if (error)
return error;
}
return error;
}
/*
* Perform the transaction.
*
* If the transaction modifies a buffer or inode, do it now. Otherwise,
* EFIs and EFDs get queued up by adding entries into the AIL for them.
*/
STATIC int
xlog_recover_commit_trans(
struct xlog *log,
struct xlog_recover *trans,
int pass,
struct list_head *buffer_list)
{
int error = 0;
int items_queued = 0;
struct xlog_recover_item *item;
struct xlog_recover_item *next;
LIST_HEAD (ra_list);
LIST_HEAD (done_list);
#define XLOG_RECOVER_COMMIT_QUEUE_MAX 100
hlist_del_init(&trans->r_list);
error = xlog_recover_reorder_trans(log, trans, pass);
if (error)
return error;
list_for_each_entry_safe(item, next, &trans->r_itemq, ri_list) {
trace_xfs_log_recover_item_recover(log, trans, item, pass);
switch (pass) {
case XLOG_RECOVER_PASS1:
if (item->ri_ops->commit_pass1)
error = item->ri_ops->commit_pass1(log, item);
break;
case XLOG_RECOVER_PASS2:
if (item->ri_ops->ra_pass2)
item->ri_ops->ra_pass2(log, item);
list_move_tail(&item->ri_list, &ra_list);
items_queued++;
if (items_queued >= XLOG_RECOVER_COMMIT_QUEUE_MAX) {
error = xlog_recover_items_pass2(log, trans,
buffer_list, &ra_list);
list_splice_tail_init(&ra_list, &done_list);
items_queued = 0;
}
break;
default:
ASSERT(0);
}
if (error)
goto out;
}
out:
if (!list_empty(&ra_list)) {
if (!error)
error = xlog_recover_items_pass2(log, trans,
buffer_list, &ra_list);
list_splice_tail_init(&ra_list, &done_list);
}
if (!list_empty(&done_list))
list_splice_init(&done_list, &trans->r_itemq);
return error;
}
STATIC void
xlog_recover_add_item(
struct list_head *head)
{
struct xlog_recover_item *item;
item = kmem_zalloc(sizeof(struct xlog_recover_item), 0);
INIT_LIST_HEAD(&item->ri_list);
list_add_tail(&item->ri_list, head);
}
STATIC int
xlog_recover_add_to_cont_trans(
struct xlog *log,
struct xlog_recover *trans,
char *dp,
int len)
{
struct xlog_recover_item *item;
char *ptr, *old_ptr;
int old_len;
/*
* If the transaction is empty, the header was split across this and the
* previous record. Copy the rest of the header.
*/
if (list_empty(&trans->r_itemq)) {
ASSERT(len <= sizeof(struct xfs_trans_header));
if (len > sizeof(struct xfs_trans_header)) {
xfs_warn(log->l_mp, "%s: bad header length", __func__);
return -EFSCORRUPTED;
}
xlog_recover_add_item(&trans->r_itemq);
ptr = (char *)&trans->r_theader +
sizeof(struct xfs_trans_header) - len;
memcpy(ptr, dp, len);
return 0;
}
/* take the tail entry */
item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
ri_list);
old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
old_len = item->ri_buf[item->ri_cnt-1].i_len;
ptr = kvrealloc(old_ptr, old_len, len + old_len, GFP_KERNEL);
if (!ptr)
return -ENOMEM;
memcpy(&ptr[old_len], dp, len);
item->ri_buf[item->ri_cnt-1].i_len += len;
item->ri_buf[item->ri_cnt-1].i_addr = ptr;
trace_xfs_log_recover_item_add_cont(log, trans, item, 0);
return 0;
}
/*
* The next region to add is the start of a new region. It could be
* a whole region or it could be the first part of a new region. Because
* of this, the assumption here is that the type and size fields of all
* format structures fit into the first 32 bits of the structure.
*
* This works because all regions must be 32 bit aligned. Therefore, we
* either have both fields or we have neither field. In the case we have
* neither field, the data part of the region is zero length. We only have
* a log_op_header and can throw away the header since a new one will appear
* later. If we have at least 4 bytes, then we can determine how many regions
* will appear in the current log item.
*/
STATIC int
xlog_recover_add_to_trans(
struct xlog *log,
struct xlog_recover *trans,
char *dp,
int len)
{
struct xfs_inode_log_format *in_f; /* any will do */
struct xlog_recover_item *item;
char *ptr;
if (!len)
return 0;
if (list_empty(&trans->r_itemq)) {
/* we need to catch log corruptions here */
if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
xfs_warn(log->l_mp, "%s: bad header magic number",
__func__);
ASSERT(0);
return -EFSCORRUPTED;
}
if (len > sizeof(struct xfs_trans_header)) {
xfs_warn(log->l_mp, "%s: bad header length", __func__);
ASSERT(0);
return -EFSCORRUPTED;
}
/*
* The transaction header can be arbitrarily split across op
* records. If we don't have the whole thing here, copy what we
* do have and handle the rest in the next record.
*/
if (len == sizeof(struct xfs_trans_header))
xlog_recover_add_item(&trans->r_itemq);
memcpy(&trans->r_theader, dp, len);
return 0;
}
ptr = kmem_alloc(len, 0);
memcpy(ptr, dp, len);
in_f = (struct xfs_inode_log_format *)ptr;
/* take the tail entry */
item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
ri_list);
if (item->ri_total != 0 &&
item->ri_total == item->ri_cnt) {
/* tail item is in use, get a new one */
xlog_recover_add_item(&trans->r_itemq);
item = list_entry(trans->r_itemq.prev,
struct xlog_recover_item, ri_list);
}
if (item->ri_total == 0) { /* first region to be added */
if (in_f->ilf_size == 0 ||
in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
xfs_warn(log->l_mp,
"bad number of regions (%d) in inode log format",
in_f->ilf_size);
ASSERT(0);
kmem_free(ptr);
return -EFSCORRUPTED;
}
item->ri_total = in_f->ilf_size;
item->ri_buf =
kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
0);
}
if (item->ri_total <= item->ri_cnt) {
xfs_warn(log->l_mp,
"log item region count (%d) overflowed size (%d)",
item->ri_cnt, item->ri_total);
ASSERT(0);
kmem_free(ptr);
return -EFSCORRUPTED;
}
/* Description region is ri_buf[0] */
item->ri_buf[item->ri_cnt].i_addr = ptr;
item->ri_buf[item->ri_cnt].i_len = len;
item->ri_cnt++;
trace_xfs_log_recover_item_add(log, trans, item, 0);
return 0;
}
/*
* Free up any resources allocated by the transaction
*
* Remember that EFIs, EFDs, and IUNLINKs are handled later.
*/
STATIC void
xlog_recover_free_trans(
struct xlog_recover *trans)
{
struct xlog_recover_item *item, *n;
int i;
hlist_del_init(&trans->r_list);
list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
/* Free the regions in the item. */
list_del(&item->ri_list);
for (i = 0; i < item->ri_cnt; i++)
kmem_free(item->ri_buf[i].i_addr);
/* Free the item itself */
kmem_free(item->ri_buf);
kmem_free(item);
}
/* Free the transaction recover structure */
kmem_free(trans);
}
/*
* On error or completion, trans is freed.
*/
STATIC int
xlog_recovery_process_trans(
struct xlog *log,
struct xlog_recover *trans,
char *dp,
unsigned int len,
unsigned int flags,
int pass,
struct list_head *buffer_list)
{
int error = 0;
bool freeit = false;
/* mask off ophdr transaction container flags */
flags &= ~XLOG_END_TRANS;
if (flags & XLOG_WAS_CONT_TRANS)
flags &= ~XLOG_CONTINUE_TRANS;
/*
* Callees must not free the trans structure. We'll decide if we need to
* free it or not based on the operation being done and it's result.
*/
switch (flags) {
/* expected flag values */
case 0:
case XLOG_CONTINUE_TRANS:
error = xlog_recover_add_to_trans(log, trans, dp, len);
break;
case XLOG_WAS_CONT_TRANS:
error = xlog_recover_add_to_cont_trans(log, trans, dp, len);
break;
case XLOG_COMMIT_TRANS:
error = xlog_recover_commit_trans(log, trans, pass,
buffer_list);
/* success or fail, we are now done with this transaction. */
freeit = true;
break;
/* unexpected flag values */
case XLOG_UNMOUNT_TRANS:
/* just skip trans */
xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
freeit = true;
break;
case XLOG_START_TRANS:
default:
xfs_warn(log->l_mp, "%s: bad flag 0x%x", __func__, flags);
ASSERT(0);
error = -EFSCORRUPTED;
break;
}
if (error || freeit)
xlog_recover_free_trans(trans);
return error;
}
/*
* Lookup the transaction recovery structure associated with the ID in the
* current ophdr. If the transaction doesn't exist and the start flag is set in
* the ophdr, then allocate a new transaction for future ID matches to find.
* Either way, return what we found during the lookup - an existing transaction
* or nothing.
*/
STATIC struct xlog_recover *
xlog_recover_ophdr_to_trans(
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
struct xlog_op_header *ohead)
{
struct xlog_recover *trans;
xlog_tid_t tid;
struct hlist_head *rhp;
tid = be32_to_cpu(ohead->oh_tid);
rhp = &rhash[XLOG_RHASH(tid)];
hlist_for_each_entry(trans, rhp, r_list) {
if (trans->r_log_tid == tid)
return trans;
}
/*
* skip over non-start transaction headers - we could be
* processing slack space before the next transaction starts
*/
if (!(ohead->oh_flags & XLOG_START_TRANS))
return NULL;
ASSERT(be32_to_cpu(ohead->oh_len) == 0);
/*
* This is a new transaction so allocate a new recovery container to
* hold the recovery ops that will follow.
*/
trans = kmem_zalloc(sizeof(struct xlog_recover), 0);
trans->r_log_tid = tid;
trans->r_lsn = be64_to_cpu(rhead->h_lsn);
INIT_LIST_HEAD(&trans->r_itemq);
INIT_HLIST_NODE(&trans->r_list);
hlist_add_head(&trans->r_list, rhp);
/*
* Nothing more to do for this ophdr. Items to be added to this new
* transaction will be in subsequent ophdr containers.
*/
return NULL;
}
STATIC int
xlog_recover_process_ophdr(
struct xlog *log,
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
struct xlog_op_header *ohead,
char *dp,
char *end,
int pass,
struct list_head *buffer_list)
{
struct xlog_recover *trans;
unsigned int len;
int error;
/* Do we understand who wrote this op? */
if (ohead->oh_clientid != XFS_TRANSACTION &&
ohead->oh_clientid != XFS_LOG) {
xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
__func__, ohead->oh_clientid);
ASSERT(0);
return -EFSCORRUPTED;
}
/*
* Check the ophdr contains all the data it is supposed to contain.
*/
len = be32_to_cpu(ohead->oh_len);
if (dp + len > end) {
xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
WARN_ON(1);
return -EFSCORRUPTED;
}
trans = xlog_recover_ophdr_to_trans(rhash, rhead, ohead);
if (!trans) {
/* nothing to do, so skip over this ophdr */
return 0;
}
/*
* The recovered buffer queue is drained only once we know that all
* recovery items for the current LSN have been processed. This is
* required because:
*
* - Buffer write submission updates the metadata LSN of the buffer.
* - Log recovery skips items with a metadata LSN >= the current LSN of
* the recovery item.
* - Separate recovery items against the same metadata buffer can share
* a current LSN. I.e., consider that the LSN of a recovery item is
* defined as the starting LSN of the first record in which its
* transaction appears, that a record can hold multiple transactions,
* and/or that a transaction can span multiple records.
*
* In other words, we are allowed to submit a buffer from log recovery
* once per current LSN. Otherwise, we may incorrectly skip recovery
* items and cause corruption.
*
* We don't know up front whether buffers are updated multiple times per
* LSN. Therefore, track the current LSN of each commit log record as it
* is processed and drain the queue when it changes. Use commit records
* because they are ordered correctly by the logging code.
*/
if (log->l_recovery_lsn != trans->r_lsn &&
ohead->oh_flags & XLOG_COMMIT_TRANS) {
error = xfs_buf_delwri_submit(buffer_list);
if (error)
return error;
log->l_recovery_lsn = trans->r_lsn;
}
return xlog_recovery_process_trans(log, trans, dp, len,
ohead->oh_flags, pass, buffer_list);
}
/*
* There are two valid states of the r_state field. 0 indicates that the
* transaction structure is in a normal state. We have either seen the
* start of the transaction or the last operation we added was not a partial
* operation. If the last operation we added to the transaction was a
* partial operation, we need to mark r_state with XLOG_WAS_CONT_TRANS.
*
* NOTE: skip LRs with 0 data length.
*/
STATIC int
xlog_recover_process_data(
struct xlog *log,
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
char *dp,
int pass,
struct list_head *buffer_list)
{
struct xlog_op_header *ohead;
char *end;
int num_logops;
int error;
end = dp + be32_to_cpu(rhead->h_len);
num_logops = be32_to_cpu(rhead->h_num_logops);
/* check the log format matches our own - else we can't recover */
if (xlog_header_check_recover(log->l_mp, rhead))
return -EIO;
trace_xfs_log_recover_record(log, rhead, pass);
while ((dp < end) && num_logops) {
ohead = (struct xlog_op_header *)dp;
dp += sizeof(*ohead);
ASSERT(dp <= end);
/* errors will abort recovery */
error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
dp, end, pass, buffer_list);
if (error)
return error;
dp += be32_to_cpu(ohead->oh_len);
num_logops--;
}
return 0;
}
/* Take all the collected deferred ops and finish them in order. */
static int
xlog_finish_defer_ops(
struct xfs_mount *mp,
struct list_head *capture_list)
{
struct xfs_defer_capture *dfc, *next;
struct xfs_trans *tp;
int error = 0;
list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
struct xfs_trans_res resv;
struct xfs_defer_resources dres;
/*
* Create a new transaction reservation from the captured
* information. Set logcount to 1 to force the new transaction
* to regrant every roll so that we can make forward progress
* in recovery no matter how full the log might be.
*/
resv.tr_logres = dfc->dfc_logres;
resv.tr_logcount = 1;
resv.tr_logflags = XFS_TRANS_PERM_LOG_RES;
error = xfs_trans_alloc(mp, &resv, dfc->dfc_blkres,
dfc->dfc_rtxres, XFS_TRANS_RESERVE, &tp);
if (error) {
xlog_force_shutdown(mp->m_log, SHUTDOWN_LOG_IO_ERROR);
return error;
}
/*
* Transfer to this new transaction all the dfops we captured
* from recovering a single intent item.
*/
list_del_init(&dfc->dfc_list);
xfs_defer_ops_continue(dfc, tp, &dres);
error = xfs_trans_commit(tp);
xfs_defer_resources_rele(&dres);
if (error)
return error;
}
ASSERT(list_empty(capture_list));
return 0;
}
/* Release all the captured defer ops and capture structures in this list. */
static void
xlog_abort_defer_ops(
struct xfs_mount *mp,
struct list_head *capture_list)
{
struct xfs_defer_capture *dfc;
struct xfs_defer_capture *next;
list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
list_del_init(&dfc->dfc_list);
xfs_defer_ops_capture_free(mp, dfc);
}
}
/*
* When this is called, all of the log intent items which did not have
* corresponding log done items should be in the AIL. What we do now is update
* the data structures associated with each one.
*
* Since we process the log intent items in normal transactions, they will be
* removed at some point after the commit. This prevents us from just walking
* down the list processing each one. We'll use a flag in the intent item to
* skip those that we've already processed and use the AIL iteration mechanism's
* generation count to try to speed this up at least a bit.
*
* When we start, we know that the intents are the only things in the AIL. As we
* process them, however, other items are added to the AIL. Hence we know we
* have started recovery on all the pending intents when we find an non-intent
* item in the AIL.
*/
STATIC int
xlog_recover_process_intents(
struct xlog *log)
{
LIST_HEAD(capture_list);
struct xfs_ail_cursor cur;
struct xfs_log_item *lip;
struct xfs_ail *ailp;
int error = 0;
#if defined(DEBUG) || defined(XFS_WARN)
xfs_lsn_t last_lsn;
#endif
ailp = log->l_ailp;
spin_lock(&ailp->ail_lock);
#if defined(DEBUG) || defined(XFS_WARN)
last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
#endif
for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
lip != NULL;
lip = xfs_trans_ail_cursor_next(ailp, &cur)) {
const struct xfs_item_ops *ops;
if (!xlog_item_is_intent(lip))
break;
/*
* We should never see a redo item with a LSN higher than
* the last transaction we found in the log at the start
* of recovery.
*/
ASSERT(XFS_LSN_CMP(last_lsn, lip->li_lsn) >= 0);
/*
* NOTE: If your intent processing routine can create more
* deferred ops, you /must/ attach them to the capture list in
* the recover routine or else those subsequent intents will be
* replayed in the wrong order!
*
* The recovery function can free the log item, so we must not
* access lip after it returns.
*/
spin_unlock(&ailp->ail_lock);
ops = lip->li_ops;
error = ops->iop_recover(lip, &capture_list);
spin_lock(&ailp->ail_lock);
if (error) {
trace_xlog_intent_recovery_failed(log->l_mp, error,
ops->iop_recover);
break;
}
}
xfs_trans_ail_cursor_done(&cur);
spin_unlock(&ailp->ail_lock);
if (error)
goto err;
error = xlog_finish_defer_ops(log->l_mp, &capture_list);
if (error)
goto err;
return 0;
err:
xlog_abort_defer_ops(log->l_mp, &capture_list);
return error;
}
/*
* A cancel occurs when the mount has failed and we're bailing out. Release all
* pending log intent items that we haven't started recovery on so they don't
* pin the AIL.
*/
STATIC void
xlog_recover_cancel_intents(
struct xlog *log)
{
struct xfs_log_item *lip;
struct xfs_ail_cursor cur;
struct xfs_ail *ailp;
ailp = log->l_ailp;
spin_lock(&ailp->ail_lock);
lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
while (lip != NULL) {
if (!xlog_item_is_intent(lip))
break;
spin_unlock(&ailp->ail_lock);
lip->li_ops->iop_release(lip);
spin_lock(&ailp->ail_lock);
lip = xfs_trans_ail_cursor_next(ailp, &cur);
}
xfs_trans_ail_cursor_done(&cur);
spin_unlock(&ailp->ail_lock);
}
/*
* This routine performs a transaction to null out a bad inode pointer
* in an agi unlinked inode hash bucket.
*/
STATIC void
xlog_recover_clear_agi_bucket(
struct xfs_perag *pag,
int bucket)
{
struct xfs_mount *mp = pag->pag_mount;
struct xfs_trans *tp;
struct xfs_agi *agi;
struct xfs_buf *agibp;
int offset;
int error;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_clearagi, 0, 0, 0, &tp);
if (error)
goto out_error;
error = xfs_read_agi(pag, tp, &agibp);
if (error)
goto out_abort;
agi = agibp->b_addr;
agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
offset = offsetof(xfs_agi_t, agi_unlinked) +
(sizeof(xfs_agino_t) * bucket);
xfs_trans_log_buf(tp, agibp, offset,
(offset + sizeof(xfs_agino_t) - 1));
error = xfs_trans_commit(tp);
if (error)
goto out_error;
return;
out_abort:
xfs_trans_cancel(tp);
out_error:
xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__,
pag->pag_agno);
return;
}
static int
xlog_recover_iunlink_bucket(
struct xfs_perag *pag,
struct xfs_agi *agi,
int bucket)
{
struct xfs_mount *mp = pag->pag_mount;
struct xfs_inode *prev_ip = NULL;
struct xfs_inode *ip;
xfs_agino_t prev_agino, agino;
int error = 0;
agino = be32_to_cpu(agi->agi_unlinked[bucket]);
while (agino != NULLAGINO) {
error = xfs_iget(mp, NULL,
XFS_AGINO_TO_INO(mp, pag->pag_agno, agino),
0, 0, &ip);
if (error)
break;
ASSERT(VFS_I(ip)->i_nlink == 0);
ASSERT(VFS_I(ip)->i_mode != 0);
xfs_iflags_clear(ip, XFS_IRECOVERY);
agino = ip->i_next_unlinked;
if (prev_ip) {
ip->i_prev_unlinked = prev_agino;
xfs_irele(prev_ip);
/*
* Ensure the inode is removed from the unlinked list
* before we continue so that it won't race with
* building the in-memory list here. This could be
* serialised with the agibp lock, but that just
* serialises via lockstepping and it's much simpler
* just to flush the inodegc queue and wait for it to
* complete.
*/
error = xfs_inodegc_flush(mp);
if (error)
break;
}
prev_agino = agino;
prev_ip = ip;
}
if (prev_ip) {
int error2;
ip->i_prev_unlinked = prev_agino;
xfs_irele(prev_ip);
error2 = xfs_inodegc_flush(mp);
if (error2 && !error)
return error2;
}
return error;
}
/*
* Recover AGI unlinked lists
*
* This is called during recovery to process any inodes which we unlinked but
* not freed when the system crashed. These inodes will be on the lists in the
* AGI blocks. What we do here is scan all the AGIs and fully truncate and free
* any inodes found on the lists. Each inode is removed from the lists when it
* has been fully truncated and is freed. The freeing of the inode and its
* removal from the list must be atomic.
*
* If everything we touch in the agi processing loop is already in memory, this
* loop can hold the cpu for a long time. It runs without lock contention,
* memory allocation contention, the need wait for IO, etc, and so will run
* until we either run out of inodes to process, run low on memory or we run out
* of log space.
*
* This behaviour is bad for latency on single CPU and non-preemptible kernels,
* and can prevent other filesystem work (such as CIL pushes) from running. This
* can lead to deadlocks if the recovery process runs out of log reservation
* space. Hence we need to yield the CPU when there is other kernel work
* scheduled on this CPU to ensure other scheduled work can run without undue
* latency.
*/
static void
xlog_recover_iunlink_ag(
struct xfs_perag *pag)
{
struct xfs_agi *agi;
struct xfs_buf *agibp;
int bucket;
int error;
error = xfs_read_agi(pag, NULL, &agibp);
if (error) {
/*
* AGI is b0rked. Don't process it.
*
* We should probably mark the filesystem as corrupt after we've
* recovered all the ag's we can....
*/
return;
}
/*
* Unlock the buffer so that it can be acquired in the normal course of
* the transaction to truncate and free each inode. Because we are not
* racing with anyone else here for the AGI buffer, we don't even need
* to hold it locked to read the initial unlinked bucket entries out of
* the buffer. We keep buffer reference though, so that it stays pinned
* in memory while we need the buffer.
*/
agi = agibp->b_addr;
xfs_buf_unlock(agibp);
for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
error = xlog_recover_iunlink_bucket(pag, agi, bucket);
if (error) {
/*
* Bucket is unrecoverable, so only a repair scan can
* free the remaining unlinked inodes. Just empty the
* bucket and remaining inodes on it unreferenced and
* unfreeable.
*/
xlog_recover_clear_agi_bucket(pag, bucket);
}
}
xfs_buf_rele(agibp);
}
static void
xlog_recover_process_iunlinks(
struct xlog *log)
{
struct xfs_perag *pag;
xfs_agnumber_t agno;
for_each_perag(log->l_mp, agno, pag)
xlog_recover_iunlink_ag(pag);
}
STATIC void
xlog_unpack_data(
struct xlog_rec_header *rhead,
char *dp,
struct xlog *log)
{
int i, j, k;
for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&
i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
*(__be32 *)dp = *(__be32 *)&rhead->h_cycle_data[i];
dp += BBSIZE;
}
if (xfs_has_logv2(log->l_mp)) {
xlog_in_core_2_t *xhdr = (xlog_in_core_2_t *)rhead;
for ( ; i < BTOBB(be32_to_cpu(rhead->h_len)); i++) {
j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
*(__be32 *)dp = xhdr[j].hic_xheader.xh_cycle_data[k];
dp += BBSIZE;
}
}
}
/*
* CRC check, unpack and process a log record.
*/
STATIC int
xlog_recover_process(
struct xlog *log,
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
char *dp,
int pass,
struct list_head *buffer_list)
{
__le32 old_crc = rhead->h_crc;
__le32 crc;
crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));
/*
* Nothing else to do if this is a CRC verification pass. Just return
* if this a record with a non-zero crc. Unfortunately, mkfs always
* sets old_crc to 0 so we must consider this valid even on v5 supers.
* Otherwise, return EFSBADCRC on failure so the callers up the stack
* know precisely what failed.
*/
if (pass == XLOG_RECOVER_CRCPASS) {
if (old_crc && crc != old_crc)
return -EFSBADCRC;
return 0;
}
/*
* We're in the normal recovery path. Issue a warning if and only if the
* CRC in the header is non-zero. This is an advisory warning and the
* zero CRC check prevents warnings from being emitted when upgrading
* the kernel from one that does not add CRCs by default.
*/
if (crc != old_crc) {
if (old_crc || xfs_has_crc(log->l_mp)) {
xfs_alert(log->l_mp,
"log record CRC mismatch: found 0x%x, expected 0x%x.",
le32_to_cpu(old_crc),
le32_to_cpu(crc));
xfs_hex_dump(dp, 32);
}
/*
* If the filesystem is CRC enabled, this mismatch becomes a
* fatal log corruption failure.
*/
if (xfs_has_crc(log->l_mp)) {
XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
return -EFSCORRUPTED;
}
}
xlog_unpack_data(rhead, dp, log);
return xlog_recover_process_data(log, rhash, rhead, dp, pass,
buffer_list);
}
STATIC int
xlog_valid_rec_header(
struct xlog *log,
struct xlog_rec_header *rhead,
xfs_daddr_t blkno,
int bufsize)
{
int hlen;
if (XFS_IS_CORRUPT(log->l_mp,
rhead->h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM)))
return -EFSCORRUPTED;
if (XFS_IS_CORRUPT(log->l_mp,
(!rhead->h_version ||
(be32_to_cpu(rhead->h_version) &
(~XLOG_VERSION_OKBITS))))) {
xfs_warn(log->l_mp, "%s: unrecognised log version (%d).",
__func__, be32_to_cpu(rhead->h_version));
return -EFSCORRUPTED;
}
/*
* LR body must have data (or it wouldn't have been written)
* and h_len must not be greater than LR buffer size.
*/
hlen = be32_to_cpu(rhead->h_len);
if (XFS_IS_CORRUPT(log->l_mp, hlen <= 0 || hlen > bufsize))
return -EFSCORRUPTED;
if (XFS_IS_CORRUPT(log->l_mp,
blkno > log->l_logBBsize || blkno > INT_MAX))
return -EFSCORRUPTED;
return 0;
}
/*
* Read the log from tail to head and process the log records found.
* Handle the two cases where the tail and head are in the same cycle
* and where the active portion of the log wraps around the end of
* the physical log separately. The pass parameter is passed through
* to the routines called to process the data and is not looked at
* here.
*/
STATIC int
xlog_do_recovery_pass(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk,
int pass,
xfs_daddr_t *first_bad) /* out: first bad log rec */
{
xlog_rec_header_t *rhead;
xfs_daddr_t blk_no, rblk_no;
xfs_daddr_t rhead_blk;
char *offset;
char *hbp, *dbp;
int error = 0, h_size, h_len;
int error2 = 0;
int bblks, split_bblks;
int hblks, split_hblks, wrapped_hblks;
int i;
struct hlist_head rhash[XLOG_RHASH_SIZE];
LIST_HEAD (buffer_list);
ASSERT(head_blk != tail_blk);
blk_no = rhead_blk = tail_blk;
for (i = 0; i < XLOG_RHASH_SIZE; i++)
INIT_HLIST_HEAD(&rhash[i]);
/*
* Read the header of the tail block and get the iclog buffer size from
* h_size. Use this to tell how many sectors make up the log header.
*/
if (xfs_has_logv2(log->l_mp)) {
/*
* When using variable length iclogs, read first sector of
* iclog header and extract the header size from it. Get a
* new hbp that is the correct size.
*/
hbp = xlog_alloc_buffer(log, 1);
if (!hbp)
return -ENOMEM;
error = xlog_bread(log, tail_blk, 1, hbp, &offset);
if (error)
goto bread_err1;
rhead = (xlog_rec_header_t *)offset;
/*
* xfsprogs has a bug where record length is based on lsunit but
* h_size (iclog size) is hardcoded to 32k. Now that we
* unconditionally CRC verify the unmount record, this means the
* log buffer can be too small for the record and cause an
* overrun.
*
* Detect this condition here. Use lsunit for the buffer size as
* long as this looks like the mkfs case. Otherwise, return an
* error to avoid a buffer overrun.
*/
h_size = be32_to_cpu(rhead->h_size);
h_len = be32_to_cpu(rhead->h_len);
if (h_len > h_size && h_len <= log->l_mp->m_logbsize &&
rhead->h_num_logops == cpu_to_be32(1)) {
xfs_warn(log->l_mp,
"invalid iclog size (%d bytes), using lsunit (%d bytes)",
h_size, log->l_mp->m_logbsize);
h_size = log->l_mp->m_logbsize;
}
error = xlog_valid_rec_header(log, rhead, tail_blk, h_size);
if (error)
goto bread_err1;
hblks = xlog_logrec_hblks(log, rhead);
if (hblks != 1) {
kmem_free(hbp);
hbp = xlog_alloc_buffer(log, hblks);
}
} else {
ASSERT(log->l_sectBBsize == 1);
hblks = 1;
hbp = xlog_alloc_buffer(log, 1);
h_size = XLOG_BIG_RECORD_BSIZE;
}
if (!hbp)
return -ENOMEM;
dbp = xlog_alloc_buffer(log, BTOBB(h_size));
if (!dbp) {
kmem_free(hbp);
return -ENOMEM;
}
memset(rhash, 0, sizeof(rhash));
if (tail_blk > head_blk) {
/*
* Perform recovery around the end of the physical log.
* When the head is not on the same cycle number as the tail,
* we can't do a sequential recovery.
*/
while (blk_no < log->l_logBBsize) {
/*
* Check for header wrapping around physical end-of-log
*/
offset = hbp;
split_hblks = 0;
wrapped_hblks = 0;
if (blk_no + hblks <= log->l_logBBsize) {
/* Read header in one read */
error = xlog_bread(log, blk_no, hblks, hbp,
&offset);
if (error)
goto bread_err2;
} else {
/* This LR is split across physical log end */
if (blk_no != log->l_logBBsize) {
/* some data before physical log end */
ASSERT(blk_no <= INT_MAX);
split_hblks = log->l_logBBsize - (int)blk_no;
ASSERT(split_hblks > 0);
error = xlog_bread(log, blk_no,
split_hblks, hbp,
&offset);
if (error)
goto bread_err2;
}
/*
* Note: this black magic still works with
* large sector sizes (non-512) only because:
* - we increased the buffer size originally
* by 1 sector giving us enough extra space
* for the second read;
* - the log start is guaranteed to be sector
* aligned;
* - we read the log end (LR header start)
* _first_, then the log start (LR header end)
* - order is important.
*/
wrapped_hblks = hblks - split_hblks;
error = xlog_bread_noalign(log, 0,
wrapped_hblks,
offset + BBTOB(split_hblks));
if (error)
goto bread_err2;
}
rhead = (xlog_rec_header_t *)offset;
error = xlog_valid_rec_header(log, rhead,
split_hblks ? blk_no : 0, h_size);
if (error)
goto bread_err2;
bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
blk_no += hblks;
/*
* Read the log record data in multiple reads if it
* wraps around the end of the log. Note that if the
* header already wrapped, blk_no could point past the
* end of the log. The record data is contiguous in
* that case.
*/
if (blk_no + bblks <= log->l_logBBsize ||
blk_no >= log->l_logBBsize) {
rblk_no = xlog_wrap_logbno(log, blk_no);
error = xlog_bread(log, rblk_no, bblks, dbp,
&offset);
if (error)
goto bread_err2;
} else {
/* This log record is split across the
* physical end of log */
offset = dbp;
split_bblks = 0;
if (blk_no != log->l_logBBsize) {
/* some data is before the physical
* end of log */
ASSERT(!wrapped_hblks);
ASSERT(blk_no <= INT_MAX);
split_bblks =
log->l_logBBsize - (int)blk_no;
ASSERT(split_bblks > 0);
error = xlog_bread(log, blk_no,
split_bblks, dbp,
&offset);
if (error)
goto bread_err2;
}
/*
* Note: this black magic still works with
* large sector sizes (non-512) only because:
* - we increased the buffer size originally
* by 1 sector giving us enough extra space
* for the second read;
* - the log start is guaranteed to be sector
* aligned;
* - we read the log end (LR header start)
* _first_, then the log start (LR header end)
* - order is important.
*/
error = xlog_bread_noalign(log, 0,
bblks - split_bblks,
offset + BBTOB(split_bblks));
if (error)
goto bread_err2;
}
error = xlog_recover_process(log, rhash, rhead, offset,
pass, &buffer_list);
if (error)
goto bread_err2;
blk_no += bblks;
rhead_blk = blk_no;
}
ASSERT(blk_no >= log->l_logBBsize);
blk_no -= log->l_logBBsize;
rhead_blk = blk_no;
}
/* read first part of physical log */
while (blk_no < head_blk) {
error = xlog_bread(log, blk_no, hblks, hbp, &offset);
if (error)
goto bread_err2;
rhead = (xlog_rec_header_t *)offset;
error = xlog_valid_rec_header(log, rhead, blk_no, h_size);
if (error)
goto bread_err2;
/* blocks in data section */
bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
error = xlog_bread(log, blk_no+hblks, bblks, dbp,
&offset);
if (error)
goto bread_err2;
error = xlog_recover_process(log, rhash, rhead, offset, pass,
&buffer_list);
if (error)
goto bread_err2;
blk_no += bblks + hblks;
rhead_blk = blk_no;
}
bread_err2:
kmem_free(dbp);
bread_err1:
kmem_free(hbp);
/*
* Submit buffers that have been added from the last record processed,
* regardless of error status.
*/
if (!list_empty(&buffer_list))
error2 = xfs_buf_delwri_submit(&buffer_list);
if (error && first_bad)
*first_bad = rhead_blk;
/*
* Transactions are freed at commit time but transactions without commit
* records on disk are never committed. Free any that may be left in the
* hash table.
*/
for (i = 0; i < XLOG_RHASH_SIZE; i++) {
struct hlist_node *tmp;
struct xlog_recover *trans;
hlist_for_each_entry_safe(trans, tmp, &rhash[i], r_list)
xlog_recover_free_trans(trans);
}
return error ? error : error2;
}
/*
* Do the recovery of the log. We actually do this in two phases.
* The two passes are necessary in order to implement the function
* of cancelling a record written into the log. The first pass
* determines those things which have been cancelled, and the
* second pass replays log items normally except for those which
* have been cancelled. The handling of the replay and cancellations
* takes place in the log item type specific routines.
*
* The table of items which have cancel records in the log is allocated
* and freed at this level, since only here do we know when all of
* the log recovery has been completed.
*/
STATIC int
xlog_do_log_recovery(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk)
{
int error;
ASSERT(head_blk != tail_blk);
/*
* First do a pass to find all of the cancelled buf log items.
* Store them in the buf_cancel_table for use in the second pass.
*/
error = xlog_alloc_buf_cancel_table(log);
if (error)
return error;
error = xlog_do_recovery_pass(log, head_blk, tail_blk,
XLOG_RECOVER_PASS1, NULL);
if (error != 0)
goto out_cancel;
/*
* Then do a second pass to actually recover the items in the log.
* When it is complete free the table of buf cancel items.
*/
error = xlog_do_recovery_pass(log, head_blk, tail_blk,
XLOG_RECOVER_PASS2, NULL);
if (!error)
xlog_check_buf_cancel_table(log);
out_cancel:
xlog_free_buf_cancel_table(log);
return error;
}
/*
* Do the actual recovery
*/
STATIC int
xlog_do_recover(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk)
{
struct xfs_mount *mp = log->l_mp;
struct xfs_buf *bp = mp->m_sb_bp;
struct xfs_sb *sbp = &mp->m_sb;
int error;
trace_xfs_log_recover(log, head_blk, tail_blk);
/*
* First replay the images in the log.
*/
error = xlog_do_log_recovery(log, head_blk, tail_blk);
if (error)
return error;
if (xlog_is_shutdown(log))
return -EIO;
/*
* We now update the tail_lsn since much of the recovery has completed
* and there may be space available to use. If there were no extent
* or iunlinks, we can free up the entire log and set the tail_lsn to
* be the last_sync_lsn. This was set in xlog_find_tail to be the
* lsn of the last known good LR on disk. If there are extent frees
* or iunlinks they will have some entries in the AIL; so we look at
* the AIL to determine how to set the tail_lsn.
*/
xlog_assign_tail_lsn(mp);
/*
* Now that we've finished replaying all buffer and inode updates,
* re-read the superblock and reverify it.
*/
xfs_buf_lock(bp);
xfs_buf_hold(bp);
error = _xfs_buf_read(bp, XBF_READ);
if (error) {
if (!xlog_is_shutdown(log)) {
xfs_buf_ioerror_alert(bp, __this_address);
ASSERT(0);
}
xfs_buf_relse(bp);
return error;
}
/* Convert superblock from on-disk format */
xfs_sb_from_disk(sbp, bp->b_addr);
xfs_buf_relse(bp);
/* re-initialise in-core superblock and geometry structures */
mp->m_features |= xfs_sb_version_to_features(sbp);
xfs_reinit_percpu_counters(mp);
error = xfs_initialize_perag(mp, sbp->sb_agcount, sbp->sb_dblocks,
&mp->m_maxagi);
if (error) {
xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
return error;
}
mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
/* Normal transactions can now occur */
clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
return 0;
}
/*
* Perform recovery and re-initialize some log variables in xlog_find_tail.
*
* Return error or zero.
*/
int
xlog_recover(
struct xlog *log)
{
xfs_daddr_t head_blk, tail_blk;
int error;
/* find the tail of the log */
error = xlog_find_tail(log, &head_blk, &tail_blk);
if (error)
return error;
/*
* The superblock was read before the log was available and thus the LSN
* could not be verified. Check the superblock LSN against the current
* LSN now that it's known.
*/
if (xfs_has_crc(log->l_mp) &&
!xfs_log_check_lsn(log->l_mp, log->l_mp->m_sb.sb_lsn))
return -EINVAL;
if (tail_blk != head_blk) {
/* There used to be a comment here:
*
* disallow recovery on read-only mounts. note -- mount
* checks for ENOSPC and turns it into an intelligent
* error message.
* ...but this is no longer true. Now, unless you specify
* NORECOVERY (in which case this function would never be
* called), we just go ahead and recover. We do this all
* under the vfs layer, so we can get away with it unless
* the device itself is read-only, in which case we fail.
*/
if ((error = xfs_dev_is_read_only(log->l_mp, "recovery"))) {
return error;
}
/*
* Version 5 superblock log feature mask validation. We know the
* log is dirty so check if there are any unknown log features
* in what we need to recover. If there are unknown features
* (e.g. unsupported transactions, then simply reject the
* attempt at recovery before touching anything.
*/
if (xfs_sb_is_v5(&log->l_mp->m_sb) &&
xfs_sb_has_incompat_log_feature(&log->l_mp->m_sb,
XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN)) {
xfs_warn(log->l_mp,
"Superblock has unknown incompatible log features (0x%x) enabled.",
(log->l_mp->m_sb.sb_features_log_incompat &
XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
xfs_warn(log->l_mp,
"The log can not be fully and/or safely recovered by this kernel.");
xfs_warn(log->l_mp,
"Please recover the log on a kernel that supports the unknown features.");
return -EINVAL;
}
/*
* Delay log recovery if the debug hook is set. This is debug
* instrumentation to coordinate simulation of I/O failures with
* log recovery.
*/
if (xfs_globals.log_recovery_delay) {
xfs_notice(log->l_mp,
"Delaying log recovery for %d seconds.",
xfs_globals.log_recovery_delay);
msleep(xfs_globals.log_recovery_delay * 1000);
}
xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
log->l_mp->m_logname ? log->l_mp->m_logname
: "internal");
error = xlog_do_recover(log, head_blk, tail_blk);
set_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
}
return error;
}
/*
* In the first part of recovery we replay inodes and buffers and build up the
* list of intents which need to be processed. Here we process the intents and
* clean up the on disk unlinked inode lists. This is separated from the first
* part of recovery so that the root and real-time bitmap inodes can be read in
* from disk in between the two stages. This is necessary so that we can free
* space in the real-time portion of the file system.
*/
int
xlog_recover_finish(
struct xlog *log)
{
int error;
error = xlog_recover_process_intents(log);
if (error) {
/*
* Cancel all the unprocessed intent items now so that we don't
* leave them pinned in the AIL. This can cause the AIL to
* livelock on the pinned item if anyone tries to push the AIL
* (inode reclaim does this) before we get around to
* xfs_log_mount_cancel.
*/
xlog_recover_cancel_intents(log);
xfs_alert(log->l_mp, "Failed to recover intents");
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
return error;
}
/*
* Sync the log to get all the intents out of the AIL. This isn't
* absolutely necessary, but it helps in case the unlink transactions
* would have problems pushing the intents out of the way.
*/
xfs_log_force(log->l_mp, XFS_LOG_SYNC);
/*
* Now that we've recovered the log and all the intents, we can clear
* the log incompat feature bits in the superblock because there's no
* longer anything to protect. We rely on the AIL push to write out the
* updated superblock after everything else.
*/
if (xfs_clear_incompat_log_features(log->l_mp)) {
error = xfs_sync_sb(log->l_mp, false);
if (error < 0) {
xfs_alert(log->l_mp,
"Failed to clear log incompat features on recovery");
return error;
}
}
xlog_recover_process_iunlinks(log);
/*
* Recover any CoW staging blocks that are still referenced by the
* ondisk refcount metadata. During mount there cannot be any live
* staging extents as we have not permitted any user modifications.
* Therefore, it is safe to free them all right now, even on a
* read-only mount.
*/
error = xfs_reflink_recover_cow(log->l_mp);
if (error) {
xfs_alert(log->l_mp,
"Failed to recover leftover CoW staging extents, err %d.",
error);
/*
* If we get an error here, make sure the log is shut down
* but return zero so that any log items committed since the
* end of intents processing can be pushed through the CIL
* and AIL.
*/
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
}
return 0;
}
void
xlog_recover_cancel(
struct xlog *log)
{
if (xlog_recovery_needed(log))
xlog_recover_cancel_intents(log);
}
| linux-master | fs/xfs/xfs_log_recover.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* Copyright (c) 2016-2018 Christoph Hellwig.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_errortag.h"
#include "xfs_error.h"
#include "xfs_trans.h"
#include "xfs_trans_space.h"
#include "xfs_inode_item.h"
#include "xfs_iomap.h"
#include "xfs_trace.h"
#include "xfs_quota.h"
#include "xfs_dquot_item.h"
#include "xfs_dquot.h"
#include "xfs_reflink.h"
#define XFS_ALLOC_ALIGN(mp, off) \
(((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
static int
xfs_alert_fsblock_zero(
xfs_inode_t *ip,
xfs_bmbt_irec_t *imap)
{
xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
"Access to block zero in inode %llu "
"start_block: %llx start_off: %llx "
"blkcnt: %llx extent-state: %x",
(unsigned long long)ip->i_ino,
(unsigned long long)imap->br_startblock,
(unsigned long long)imap->br_startoff,
(unsigned long long)imap->br_blockcount,
imap->br_state);
return -EFSCORRUPTED;
}
u64
xfs_iomap_inode_sequence(
struct xfs_inode *ip,
u16 iomap_flags)
{
u64 cookie = 0;
if (iomap_flags & IOMAP_F_XATTR)
return READ_ONCE(ip->i_af.if_seq);
if ((iomap_flags & IOMAP_F_SHARED) && ip->i_cowfp)
cookie = (u64)READ_ONCE(ip->i_cowfp->if_seq) << 32;
return cookie | READ_ONCE(ip->i_df.if_seq);
}
/*
* Check that the iomap passed to us is still valid for the given offset and
* length.
*/
static bool
xfs_iomap_valid(
struct inode *inode,
const struct iomap *iomap)
{
struct xfs_inode *ip = XFS_I(inode);
if (iomap->validity_cookie !=
xfs_iomap_inode_sequence(ip, iomap->flags)) {
trace_xfs_iomap_invalid(ip, iomap);
return false;
}
XFS_ERRORTAG_DELAY(ip->i_mount, XFS_ERRTAG_WRITE_DELAY_MS);
return true;
}
static const struct iomap_folio_ops xfs_iomap_folio_ops = {
.iomap_valid = xfs_iomap_valid,
};
int
xfs_bmbt_to_iomap(
struct xfs_inode *ip,
struct iomap *iomap,
struct xfs_bmbt_irec *imap,
unsigned int mapping_flags,
u16 iomap_flags,
u64 sequence_cookie)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock)))
return xfs_alert_fsblock_zero(ip, imap);
if (imap->br_startblock == HOLESTARTBLOCK) {
iomap->addr = IOMAP_NULL_ADDR;
iomap->type = IOMAP_HOLE;
} else if (imap->br_startblock == DELAYSTARTBLOCK ||
isnullstartblock(imap->br_startblock)) {
iomap->addr = IOMAP_NULL_ADDR;
iomap->type = IOMAP_DELALLOC;
} else {
iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
if (mapping_flags & IOMAP_DAX)
iomap->addr += target->bt_dax_part_off;
if (imap->br_state == XFS_EXT_UNWRITTEN)
iomap->type = IOMAP_UNWRITTEN;
else
iomap->type = IOMAP_MAPPED;
}
iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
if (mapping_flags & IOMAP_DAX)
iomap->dax_dev = target->bt_daxdev;
else
iomap->bdev = target->bt_bdev;
iomap->flags = iomap_flags;
if (xfs_ipincount(ip) &&
(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
iomap->flags |= IOMAP_F_DIRTY;
iomap->validity_cookie = sequence_cookie;
iomap->folio_ops = &xfs_iomap_folio_ops;
return 0;
}
static void
xfs_hole_to_iomap(
struct xfs_inode *ip,
struct iomap *iomap,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t end_fsb)
{
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
iomap->addr = IOMAP_NULL_ADDR;
iomap->type = IOMAP_HOLE;
iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
iomap->bdev = target->bt_bdev;
iomap->dax_dev = target->bt_daxdev;
}
static inline xfs_fileoff_t
xfs_iomap_end_fsb(
struct xfs_mount *mp,
loff_t offset,
loff_t count)
{
ASSERT(offset <= mp->m_super->s_maxbytes);
return min(XFS_B_TO_FSB(mp, offset + count),
XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
}
static xfs_extlen_t
xfs_eof_alignment(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
xfs_extlen_t align = 0;
if (!XFS_IS_REALTIME_INODE(ip)) {
/*
* Round up the allocation request to a stripe unit
* (m_dalign) boundary if the file size is >= stripe unit
* size, and we are allocating past the allocation eof.
*
* If mounted with the "-o swalloc" option the alignment is
* increased from the strip unit size to the stripe width.
*/
if (mp->m_swidth && xfs_has_swalloc(mp))
align = mp->m_swidth;
else if (mp->m_dalign)
align = mp->m_dalign;
if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
align = 0;
}
return align;
}
/*
* Check if last_fsb is outside the last extent, and if so grow it to the next
* stripe unit boundary.
*/
xfs_fileoff_t
xfs_iomap_eof_align_last_fsb(
struct xfs_inode *ip,
xfs_fileoff_t end_fsb)
{
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
xfs_extlen_t extsz = xfs_get_extsz_hint(ip);
xfs_extlen_t align = xfs_eof_alignment(ip);
struct xfs_bmbt_irec irec;
struct xfs_iext_cursor icur;
ASSERT(!xfs_need_iread_extents(ifp));
/*
* Always round up the allocation request to the extent hint boundary.
*/
if (extsz) {
if (align)
align = roundup_64(align, extsz);
else
align = extsz;
}
if (align) {
xfs_fileoff_t aligned_end_fsb = roundup_64(end_fsb, align);
xfs_iext_last(ifp, &icur);
if (!xfs_iext_get_extent(ifp, &icur, &irec) ||
aligned_end_fsb >= irec.br_startoff + irec.br_blockcount)
return aligned_end_fsb;
}
return end_fsb;
}
int
xfs_iomap_write_direct(
struct xfs_inode *ip,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t count_fsb,
unsigned int flags,
struct xfs_bmbt_irec *imap,
u64 *seq)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
xfs_filblks_t resaligned;
int nimaps;
unsigned int dblocks, rblocks;
bool force = false;
int error;
int bmapi_flags = XFS_BMAPI_PREALLOC;
int nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
ASSERT(count_fsb > 0);
resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
xfs_get_extsz_hint(ip));
if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
rblocks = resaligned;
} else {
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
rblocks = 0;
}
error = xfs_qm_dqattach(ip);
if (error)
return error;
/*
* For DAX, we do not allocate unwritten extents, but instead we zero
* the block before we commit the transaction. Ideally we'd like to do
* this outside the transaction context, but if we commit and then crash
* we may not have zeroed the blocks and this will be exposed on
* recovery of the allocation. Hence we must zero before commit.
*
* Further, if we are mapping unwritten extents here, we need to zero
* and convert them to written so that we don't need an unwritten extent
* callback for DAX. This also means that we need to be able to dip into
* the reserve block pool for bmbt block allocation if there is no space
* left but we need to do unwritten extent conversion.
*/
if (flags & IOMAP_DAX) {
bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
if (imap->br_state == XFS_EXT_UNWRITTEN) {
force = true;
nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
}
}
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
rblocks, force, &tp);
if (error)
return error;
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, nr_exts);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip, nr_exts);
if (error)
goto out_trans_cancel;
/*
* From this point onwards we overwrite the imap pointer that the
* caller gave to us.
*/
nimaps = 1;
error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flags, 0,
imap, &nimaps);
if (error)
goto out_trans_cancel;
/*
* Complete the transaction
*/
error = xfs_trans_commit(tp);
if (error)
goto out_unlock;
/*
* Copy any maps to caller's array and return any error.
*/
if (nimaps == 0) {
error = -ENOSPC;
goto out_unlock;
}
if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock)))
error = xfs_alert_fsblock_zero(ip, imap);
out_unlock:
*seq = xfs_iomap_inode_sequence(ip, 0);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
goto out_unlock;
}
STATIC bool
xfs_quota_need_throttle(
struct xfs_inode *ip,
xfs_dqtype_t type,
xfs_fsblock_t alloc_blocks)
{
struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
if (!dq || !xfs_this_quota_on(ip->i_mount, type))
return false;
/* no hi watermark, no throttle */
if (!dq->q_prealloc_hi_wmark)
return false;
/* under the lo watermark, no throttle */
if (dq->q_blk.reserved + alloc_blocks < dq->q_prealloc_lo_wmark)
return false;
return true;
}
STATIC void
xfs_quota_calc_throttle(
struct xfs_inode *ip,
xfs_dqtype_t type,
xfs_fsblock_t *qblocks,
int *qshift,
int64_t *qfreesp)
{
struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
int64_t freesp;
int shift = 0;
/* no dq, or over hi wmark, squash the prealloc completely */
if (!dq || dq->q_blk.reserved >= dq->q_prealloc_hi_wmark) {
*qblocks = 0;
*qfreesp = 0;
return;
}
freesp = dq->q_prealloc_hi_wmark - dq->q_blk.reserved;
if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
shift = 2;
if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
shift += 2;
if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
shift += 2;
}
if (freesp < *qfreesp)
*qfreesp = freesp;
/* only overwrite the throttle values if we are more aggressive */
if ((freesp >> shift) < (*qblocks >> *qshift)) {
*qblocks = freesp;
*qshift = shift;
}
}
/*
* If we don't have a user specified preallocation size, dynamically increase
* the preallocation size as the size of the file grows. Cap the maximum size
* at a single extent or less if the filesystem is near full. The closer the
* filesystem is to being full, the smaller the maximum preallocation.
*/
STATIC xfs_fsblock_t
xfs_iomap_prealloc_size(
struct xfs_inode *ip,
int whichfork,
loff_t offset,
loff_t count,
struct xfs_iext_cursor *icur)
{
struct xfs_iext_cursor ncur = *icur;
struct xfs_bmbt_irec prev, got;
struct xfs_mount *mp = ip->i_mount;
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
int64_t freesp;
xfs_fsblock_t qblocks;
xfs_fsblock_t alloc_blocks = 0;
xfs_extlen_t plen;
int shift = 0;
int qshift = 0;
/*
* As an exception we don't do any preallocation at all if the file is
* smaller than the minimum preallocation and we are using the default
* dynamic preallocation scheme, as it is likely this is the only write
* to the file that is going to be done.
*/
if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_allocsize_blocks))
return 0;
/*
* Use the minimum preallocation size for small files or if we are
* writing right after a hole.
*/
if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
!xfs_iext_prev_extent(ifp, &ncur, &prev) ||
prev.br_startoff + prev.br_blockcount < offset_fsb)
return mp->m_allocsize_blocks;
/*
* Take the size of the preceding data extents as the basis for the
* preallocation size. Note that we don't care if the previous extents
* are written or not.
*/
plen = prev.br_blockcount;
while (xfs_iext_prev_extent(ifp, &ncur, &got)) {
if (plen > XFS_MAX_BMBT_EXTLEN / 2 ||
isnullstartblock(got.br_startblock) ||
got.br_startoff + got.br_blockcount != prev.br_startoff ||
got.br_startblock + got.br_blockcount != prev.br_startblock)
break;
plen += got.br_blockcount;
prev = got;
}
/*
* If the size of the extents is greater than half the maximum extent
* length, then use the current offset as the basis. This ensures that
* for large files the preallocation size always extends to
* XFS_BMBT_MAX_EXTLEN rather than falling short due to things like stripe
* unit/width alignment of real extents.
*/
alloc_blocks = plen * 2;
if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
alloc_blocks = XFS_B_TO_FSB(mp, offset);
qblocks = alloc_blocks;
/*
* XFS_BMBT_MAX_EXTLEN is not a power of two value but we round the prealloc
* down to the nearest power of two value after throttling. To prevent
* the round down from unconditionally reducing the maximum supported
* prealloc size, we round up first, apply appropriate throttling, round
* down and cap the value to XFS_BMBT_MAX_EXTLEN.
*/
alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(XFS_MAX_BMBT_EXTLEN),
alloc_blocks);
freesp = percpu_counter_read_positive(&mp->m_fdblocks);
if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
shift = 2;
if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
shift++;
if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
shift++;
if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
shift++;
if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
shift++;
}
/*
* Check each quota to cap the prealloc size, provide a shift value to
* throttle with and adjust amount of available space.
*/
if (xfs_quota_need_throttle(ip, XFS_DQTYPE_USER, alloc_blocks))
xfs_quota_calc_throttle(ip, XFS_DQTYPE_USER, &qblocks, &qshift,
&freesp);
if (xfs_quota_need_throttle(ip, XFS_DQTYPE_GROUP, alloc_blocks))
xfs_quota_calc_throttle(ip, XFS_DQTYPE_GROUP, &qblocks, &qshift,
&freesp);
if (xfs_quota_need_throttle(ip, XFS_DQTYPE_PROJ, alloc_blocks))
xfs_quota_calc_throttle(ip, XFS_DQTYPE_PROJ, &qblocks, &qshift,
&freesp);
/*
* The final prealloc size is set to the minimum of free space available
* in each of the quotas and the overall filesystem.
*
* The shift throttle value is set to the maximum value as determined by
* the global low free space values and per-quota low free space values.
*/
alloc_blocks = min(alloc_blocks, qblocks);
shift = max(shift, qshift);
if (shift)
alloc_blocks >>= shift;
/*
* rounddown_pow_of_two() returns an undefined result if we pass in
* alloc_blocks = 0.
*/
if (alloc_blocks)
alloc_blocks = rounddown_pow_of_two(alloc_blocks);
if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
alloc_blocks = XFS_MAX_BMBT_EXTLEN;
/*
* If we are still trying to allocate more space than is
* available, squash the prealloc hard. This can happen if we
* have a large file on a small filesystem and the above
* lowspace thresholds are smaller than XFS_BMBT_MAX_EXTLEN.
*/
while (alloc_blocks && alloc_blocks >= freesp)
alloc_blocks >>= 4;
if (alloc_blocks < mp->m_allocsize_blocks)
alloc_blocks = mp->m_allocsize_blocks;
trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
mp->m_allocsize_blocks);
return alloc_blocks;
}
int
xfs_iomap_write_unwritten(
xfs_inode_t *ip,
xfs_off_t offset,
xfs_off_t count,
bool update_isize)
{
xfs_mount_t *mp = ip->i_mount;
xfs_fileoff_t offset_fsb;
xfs_filblks_t count_fsb;
xfs_filblks_t numblks_fsb;
int nimaps;
xfs_trans_t *tp;
xfs_bmbt_irec_t imap;
struct inode *inode = VFS_I(ip);
xfs_fsize_t i_size;
uint resblks;
int error;
trace_xfs_unwritten_convert(ip, offset, count);
offset_fsb = XFS_B_TO_FSBT(mp, offset);
count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
/*
* Reserve enough blocks in this transaction for two complete extent
* btree splits. We may be converting the middle part of an unwritten
* extent and in this case we will insert two new extents in the btree
* each of which could cause a full split.
*
* This reservation amount will be used in the first call to
* xfs_bmbt_split() to select an AG with enough space to satisfy the
* rest of the operation.
*/
resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
/* Attach dquots so that bmbt splits are accounted correctly. */
error = xfs_qm_dqattach(ip);
if (error)
return error;
do {
/*
* Set up a transaction to convert the range of extents
* from unwritten to real. Do allocations in a loop until
* we have covered the range passed in.
*
* Note that we can't risk to recursing back into the filesystem
* here as we might be asked to write out the same inode that we
* complete here and might deadlock on the iolock.
*/
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks,
0, true, &tp);
if (error)
return error;
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_WRITE_UNWRITTEN_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip,
XFS_IEXT_WRITE_UNWRITTEN_CNT);
if (error)
goto error_on_bmapi_transaction;
/*
* Modify the unwritten extent state of the buffer.
*/
nimaps = 1;
error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
XFS_BMAPI_CONVERT, resblks, &imap,
&nimaps);
if (error)
goto error_on_bmapi_transaction;
/*
* Log the updated inode size as we go. We have to be careful
* to only log it up to the actual write offset if it is
* halfway into a block.
*/
i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
if (i_size > offset + count)
i_size = offset + count;
if (update_isize && i_size > i_size_read(inode))
i_size_write(inode, i_size);
i_size = xfs_new_eof(ip, i_size);
if (i_size) {
ip->i_disk_size = i_size;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
}
error = xfs_trans_commit(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
if (error)
return error;
if (unlikely(!xfs_valid_startblock(ip, imap.br_startblock)))
return xfs_alert_fsblock_zero(ip, &imap);
if ((numblks_fsb = imap.br_blockcount) == 0) {
/*
* The numblks_fsb value should always get
* smaller, otherwise the loop is stuck.
*/
ASSERT(imap.br_blockcount);
break;
}
offset_fsb += numblks_fsb;
count_fsb -= numblks_fsb;
} while (count_fsb > 0);
return 0;
error_on_bmapi_transaction:
xfs_trans_cancel(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
static inline bool
imap_needs_alloc(
struct inode *inode,
unsigned flags,
struct xfs_bmbt_irec *imap,
int nimaps)
{
/* don't allocate blocks when just zeroing */
if (flags & IOMAP_ZERO)
return false;
if (!nimaps ||
imap->br_startblock == HOLESTARTBLOCK ||
imap->br_startblock == DELAYSTARTBLOCK)
return true;
/* we convert unwritten extents before copying the data for DAX */
if ((flags & IOMAP_DAX) && imap->br_state == XFS_EXT_UNWRITTEN)
return true;
return false;
}
static inline bool
imap_needs_cow(
struct xfs_inode *ip,
unsigned int flags,
struct xfs_bmbt_irec *imap,
int nimaps)
{
if (!xfs_is_cow_inode(ip))
return false;
/* when zeroing we don't have to COW holes or unwritten extents */
if (flags & IOMAP_ZERO) {
if (!nimaps ||
imap->br_startblock == HOLESTARTBLOCK ||
imap->br_state == XFS_EXT_UNWRITTEN)
return false;
}
return true;
}
static int
xfs_ilock_for_iomap(
struct xfs_inode *ip,
unsigned flags,
unsigned *lockmode)
{
unsigned int mode = *lockmode;
bool is_write = flags & (IOMAP_WRITE | IOMAP_ZERO);
/*
* COW writes may allocate delalloc space or convert unwritten COW
* extents, so we need to make sure to take the lock exclusively here.
*/
if (xfs_is_cow_inode(ip) && is_write)
mode = XFS_ILOCK_EXCL;
/*
* Extents not yet cached requires exclusive access, don't block. This
* is an opencoded xfs_ilock_data_map_shared() call but with
* non-blocking behaviour.
*/
if (xfs_need_iread_extents(&ip->i_df)) {
if (flags & IOMAP_NOWAIT)
return -EAGAIN;
mode = XFS_ILOCK_EXCL;
}
relock:
if (flags & IOMAP_NOWAIT) {
if (!xfs_ilock_nowait(ip, mode))
return -EAGAIN;
} else {
xfs_ilock(ip, mode);
}
/*
* The reflink iflag could have changed since the earlier unlocked
* check, so if we got ILOCK_SHARED for a write and but we're now a
* reflink inode we have to switch to ILOCK_EXCL and relock.
*/
if (mode == XFS_ILOCK_SHARED && is_write && xfs_is_cow_inode(ip)) {
xfs_iunlock(ip, mode);
mode = XFS_ILOCK_EXCL;
goto relock;
}
*lockmode = mode;
return 0;
}
/*
* Check that the imap we are going to return to the caller spans the entire
* range that the caller requested for the IO.
*/
static bool
imap_spans_range(
struct xfs_bmbt_irec *imap,
xfs_fileoff_t offset_fsb,
xfs_fileoff_t end_fsb)
{
if (imap->br_startoff > offset_fsb)
return false;
if (imap->br_startoff + imap->br_blockcount < end_fsb)
return false;
return true;
}
static int
xfs_direct_write_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t length,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec imap, cmap;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
int nimaps = 1, error = 0;
bool shared = false;
u16 iomap_flags = 0;
unsigned int lockmode = XFS_ILOCK_SHARED;
u64 seq;
ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
if (xfs_is_shutdown(mp))
return -EIO;
/*
* Writes that span EOF might trigger an IO size update on completion,
* so consider them to be dirty for the purposes of O_DSYNC even if
* there is no other metadata changes pending or have been made here.
*/
if (offset + length > i_size_read(inode))
iomap_flags |= IOMAP_F_DIRTY;
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, 0);
if (error)
goto out_unlock;
if (imap_needs_cow(ip, flags, &imap, nimaps)) {
error = -EAGAIN;
if (flags & IOMAP_NOWAIT)
goto out_unlock;
/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
&lockmode,
(flags & IOMAP_DIRECT) || IS_DAX(inode));
if (error)
goto out_unlock;
if (shared)
goto out_found_cow;
end_fsb = imap.br_startoff + imap.br_blockcount;
length = XFS_FSB_TO_B(mp, end_fsb) - offset;
}
if (imap_needs_alloc(inode, flags, &imap, nimaps))
goto allocate_blocks;
/*
* NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
* a single map so that we avoid partial IO failures due to the rest of
* the I/O range not covered by this map triggering an EAGAIN condition
* when it is subsequently mapped and aborting the I/O.
*/
if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
error = -EAGAIN;
if (!imap_spans_range(&imap, offset_fsb, end_fsb))
goto out_unlock;
}
/*
* For overwrite only I/O, we cannot convert unwritten extents without
* requiring sub-block zeroing. This can only be done under an
* exclusive IOLOCK, hence return -EAGAIN if this is not a written
* extent to tell the caller to try again.
*/
if (flags & IOMAP_OVERWRITE_ONLY) {
error = -EAGAIN;
if (imap.br_state != XFS_EXT_NORM &&
((offset | length) & mp->m_blockmask))
goto out_unlock;
}
seq = xfs_iomap_inode_sequence(ip, iomap_flags);
xfs_iunlock(ip, lockmode);
trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq);
allocate_blocks:
error = -EAGAIN;
if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
goto out_unlock;
/*
* We cap the maximum length we map to a sane size to keep the chunks
* of work done where somewhat symmetric with the work writeback does.
* This is a completely arbitrary number pulled out of thin air as a
* best guess for initial testing.
*
* Note that the values needs to be less than 32-bits wide until the
* lower level functions are updated.
*/
length = min_t(loff_t, length, 1024 * PAGE_SIZE);
end_fsb = xfs_iomap_end_fsb(mp, offset, length);
if (offset + length > XFS_ISIZE(ip))
end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
xfs_iunlock(ip, lockmode);
error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
flags, &imap, &seq);
if (error)
return error;
trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
iomap_flags | IOMAP_F_NEW, seq);
out_found_cow:
length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
if (imap.br_startblock != HOLESTARTBLOCK) {
seq = xfs_iomap_inode_sequence(ip, 0);
error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
if (error)
goto out_unlock;
}
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
xfs_iunlock(ip, lockmode);
return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq);
out_unlock:
if (lockmode)
xfs_iunlock(ip, lockmode);
return error;
}
const struct iomap_ops xfs_direct_write_iomap_ops = {
.iomap_begin = xfs_direct_write_iomap_begin,
};
static int
xfs_dax_write_iomap_end(
struct inode *inode,
loff_t pos,
loff_t length,
ssize_t written,
unsigned flags,
struct iomap *iomap)
{
struct xfs_inode *ip = XFS_I(inode);
if (!xfs_is_cow_inode(ip))
return 0;
if (!written) {
xfs_reflink_cancel_cow_range(ip, pos, length, true);
return 0;
}
return xfs_reflink_end_cow(ip, pos, written);
}
const struct iomap_ops xfs_dax_write_iomap_ops = {
.iomap_begin = xfs_direct_write_iomap_begin,
.iomap_end = xfs_dax_write_iomap_end,
};
static int
xfs_buffered_write_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t count,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, count);
struct xfs_bmbt_irec imap, cmap;
struct xfs_iext_cursor icur, ccur;
xfs_fsblock_t prealloc_blocks = 0;
bool eof = false, cow_eof = false, shared = false;
int allocfork = XFS_DATA_FORK;
int error = 0;
unsigned int lockmode = XFS_ILOCK_EXCL;
u64 seq;
if (xfs_is_shutdown(mp))
return -EIO;
/* we can't use delayed allocations when using extent size hints */
if (xfs_get_extsz_hint(ip))
return xfs_direct_write_iomap_begin(inode, offset, count,
flags, iomap, srcmap);
ASSERT(!XFS_IS_REALTIME_INODE(ip));
error = xfs_qm_dqattach(ip);
if (error)
return error;
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
error = -EFSCORRUPTED;
goto out_unlock;
}
XFS_STATS_INC(mp, xs_blk_mapw);
error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
if (error)
goto out_unlock;
/*
* Search the data fork first to look up our source mapping. We
* always need the data fork map, as we have to return it to the
* iomap code so that the higher level write code can read data in to
* perform read-modify-write cycles for unaligned writes.
*/
eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap);
if (eof)
imap.br_startoff = end_fsb; /* fake hole until the end */
/* We never need to allocate blocks for zeroing or unsharing a hole. */
if ((flags & (IOMAP_UNSHARE | IOMAP_ZERO)) &&
imap.br_startoff > offset_fsb) {
xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff);
goto out_unlock;
}
/*
* Search the COW fork extent list even if we did not find a data fork
* extent. This serves two purposes: first this implements the
* speculative preallocation using cowextsize, so that we also unshare
* block adjacent to shared blocks instead of just the shared blocks
* themselves. Second the lookup in the extent list is generally faster
* than going out to the shared extent tree.
*/
if (xfs_is_cow_inode(ip)) {
if (!ip->i_cowfp) {
ASSERT(!xfs_is_reflink_inode(ip));
xfs_ifork_init_cow(ip);
}
cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb,
&ccur, &cmap);
if (!cow_eof && cmap.br_startoff <= offset_fsb) {
trace_xfs_reflink_cow_found(ip, &cmap);
goto found_cow;
}
}
if (imap.br_startoff <= offset_fsb) {
/*
* For reflink files we may need a delalloc reservation when
* overwriting shared extents. This includes zeroing of
* existing extents that contain data.
*/
if (!xfs_is_cow_inode(ip) ||
((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) {
trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
&imap);
goto found_imap;
}
xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
/* Trim the mapping to the nearest shared extent boundary. */
error = xfs_bmap_trim_cow(ip, &imap, &shared);
if (error)
goto out_unlock;
/* Not shared? Just report the (potentially capped) extent. */
if (!shared) {
trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
&imap);
goto found_imap;
}
/*
* Fork all the shared blocks from our write offset until the
* end of the extent.
*/
allocfork = XFS_COW_FORK;
end_fsb = imap.br_startoff + imap.br_blockcount;
} else {
/*
* We cap the maximum length we map here to MAX_WRITEBACK_PAGES
* pages to keep the chunks of work done where somewhat
* symmetric with the work writeback does. This is a completely
* arbitrary number pulled out of thin air.
*
* Note that the values needs to be less than 32-bits wide until
* the lower level functions are updated.
*/
count = min_t(loff_t, count, 1024 * PAGE_SIZE);
end_fsb = xfs_iomap_end_fsb(mp, offset, count);
if (xfs_is_always_cow_inode(ip))
allocfork = XFS_COW_FORK;
}
if (eof && offset + count > XFS_ISIZE(ip)) {
/*
* Determine the initial size of the preallocation.
* We clean up any extra preallocation when the file is closed.
*/
if (xfs_has_allocsize(mp))
prealloc_blocks = mp->m_allocsize_blocks;
else if (allocfork == XFS_DATA_FORK)
prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
offset, count, &icur);
else
prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
offset, count, &ccur);
if (prealloc_blocks) {
xfs_extlen_t align;
xfs_off_t end_offset;
xfs_fileoff_t p_end_fsb;
end_offset = XFS_ALLOC_ALIGN(mp, offset + count - 1);
p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
prealloc_blocks;
align = xfs_eof_alignment(ip);
if (align)
p_end_fsb = roundup_64(p_end_fsb, align);
p_end_fsb = min(p_end_fsb,
XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
ASSERT(p_end_fsb > offset_fsb);
prealloc_blocks = p_end_fsb - end_fsb;
}
}
retry:
error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
end_fsb - offset_fsb, prealloc_blocks,
allocfork == XFS_DATA_FORK ? &imap : &cmap,
allocfork == XFS_DATA_FORK ? &icur : &ccur,
allocfork == XFS_DATA_FORK ? eof : cow_eof);
switch (error) {
case 0:
break;
case -ENOSPC:
case -EDQUOT:
/* retry without any preallocation */
trace_xfs_delalloc_enospc(ip, offset, count);
if (prealloc_blocks) {
prealloc_blocks = 0;
goto retry;
}
fallthrough;
default:
goto out_unlock;
}
if (allocfork == XFS_COW_FORK) {
trace_xfs_iomap_alloc(ip, offset, count, allocfork, &cmap);
goto found_cow;
}
/*
* Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
* them out if the write happens to fail.
*/
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
found_imap:
seq = xfs_iomap_inode_sequence(ip, 0);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
found_cow:
seq = xfs_iomap_inode_sequence(ip, 0);
if (imap.br_startoff <= offset_fsb) {
error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
if (error)
goto out_unlock;
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
IOMAP_F_SHARED, seq);
}
xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
static int
xfs_buffered_write_delalloc_punch(
struct inode *inode,
loff_t offset,
loff_t length)
{
return xfs_bmap_punch_delalloc_range(XFS_I(inode), offset,
offset + length);
}
static int
xfs_buffered_write_iomap_end(
struct inode *inode,
loff_t offset,
loff_t length,
ssize_t written,
unsigned flags,
struct iomap *iomap)
{
struct xfs_mount *mp = XFS_M(inode->i_sb);
int error;
error = iomap_file_buffered_write_punch_delalloc(inode, iomap, offset,
length, written, &xfs_buffered_write_delalloc_punch);
if (error && !xfs_is_shutdown(mp)) {
xfs_alert(mp, "%s: unable to clean up ino 0x%llx",
__func__, XFS_I(inode)->i_ino);
return error;
}
return 0;
}
const struct iomap_ops xfs_buffered_write_iomap_ops = {
.iomap_begin = xfs_buffered_write_iomap_begin,
.iomap_end = xfs_buffered_write_iomap_end,
};
/*
* iomap_page_mkwrite() will never fail in a way that requires delalloc extents
* that it allocated to be revoked. Hence we do not need an .iomap_end method
* for this operation.
*/
const struct iomap_ops xfs_page_mkwrite_iomap_ops = {
.iomap_begin = xfs_buffered_write_iomap_begin,
};
static int
xfs_read_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t length,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec imap;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
int nimaps = 1, error = 0;
bool shared = false;
unsigned int lockmode = XFS_ILOCK_SHARED;
u64 seq;
ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
if (xfs_is_shutdown(mp))
return -EIO;
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, 0);
if (!error && ((flags & IOMAP_REPORT) || IS_DAX(inode)))
error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
seq = xfs_iomap_inode_sequence(ip, shared ? IOMAP_F_SHARED : 0);
xfs_iunlock(ip, lockmode);
if (error)
return error;
trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
shared ? IOMAP_F_SHARED : 0, seq);
}
const struct iomap_ops xfs_read_iomap_ops = {
.iomap_begin = xfs_read_iomap_begin,
};
static int
xfs_seek_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t length,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
xfs_fileoff_t cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
struct xfs_iext_cursor icur;
struct xfs_bmbt_irec imap, cmap;
int error = 0;
unsigned lockmode;
u64 seq;
if (xfs_is_shutdown(mp))
return -EIO;
lockmode = xfs_ilock_data_map_shared(ip);
error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
if (error)
goto out_unlock;
if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
/*
* If we found a data extent we are done.
*/
if (imap.br_startoff <= offset_fsb)
goto done;
data_fsb = imap.br_startoff;
} else {
/*
* Fake a hole until the end of the file.
*/
data_fsb = xfs_iomap_end_fsb(mp, offset, length);
}
/*
* If a COW fork extent covers the hole, report it - capped to the next
* data fork extent:
*/
if (xfs_inode_has_cow_data(ip) &&
xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
cow_fsb = cmap.br_startoff;
if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
if (data_fsb < cow_fsb + cmap.br_blockcount)
end_fsb = min(end_fsb, data_fsb);
xfs_trim_extent(&cmap, offset_fsb, end_fsb);
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
IOMAP_F_SHARED, seq);
/*
* This is a COW extent, so we must probe the page cache
* because there could be dirty page cache being backed
* by this extent.
*/
iomap->type = IOMAP_UNWRITTEN;
goto out_unlock;
}
/*
* Else report a hole, capped to the next found data or COW extent.
*/
if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
imap.br_blockcount = cow_fsb - offset_fsb;
else
imap.br_blockcount = data_fsb - offset_fsb;
imap.br_startoff = offset_fsb;
imap.br_startblock = HOLESTARTBLOCK;
imap.br_state = XFS_EXT_NORM;
done:
seq = xfs_iomap_inode_sequence(ip, 0);
xfs_trim_extent(&imap, offset_fsb, end_fsb);
error = xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
out_unlock:
xfs_iunlock(ip, lockmode);
return error;
}
const struct iomap_ops xfs_seek_iomap_ops = {
.iomap_begin = xfs_seek_iomap_begin,
};
static int
xfs_xattr_iomap_begin(
struct inode *inode,
loff_t offset,
loff_t length,
unsigned flags,
struct iomap *iomap,
struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
struct xfs_bmbt_irec imap;
int nimaps = 1, error = 0;
unsigned lockmode;
int seq;
if (xfs_is_shutdown(mp))
return -EIO;
lockmode = xfs_ilock_attr_map_shared(ip);
/* if there are no attribute fork or extents, return ENOENT */
if (!xfs_inode_has_attr_fork(ip) || !ip->i_af.if_nextents) {
error = -ENOENT;
goto out_unlock;
}
ASSERT(ip->i_af.if_format != XFS_DINODE_FMT_LOCAL);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, XFS_BMAPI_ATTRFORK);
out_unlock:
seq = xfs_iomap_inode_sequence(ip, IOMAP_F_XATTR);
xfs_iunlock(ip, lockmode);
if (error)
return error;
ASSERT(nimaps);
return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_XATTR, seq);
}
const struct iomap_ops xfs_xattr_iomap_ops = {
.iomap_begin = xfs_xattr_iomap_begin,
};
int
xfs_zero_range(
struct xfs_inode *ip,
loff_t pos,
loff_t len,
bool *did_zero)
{
struct inode *inode = VFS_I(ip);
if (IS_DAX(inode))
return dax_zero_range(inode, pos, len, did_zero,
&xfs_dax_write_iomap_ops);
return iomap_zero_range(inode, pos, len, did_zero,
&xfs_buffered_write_iomap_ops);
}
int
xfs_truncate_page(
struct xfs_inode *ip,
loff_t pos,
bool *did_zero)
{
struct inode *inode = VFS_I(ip);
if (IS_DAX(inode))
return dax_truncate_page(inode, pos, did_zero,
&xfs_dax_write_iomap_ops);
return iomap_truncate_page(inode, pos, did_zero,
&xfs_buffered_write_iomap_ops);
}
| linux-master | fs/xfs/xfs_iomap.c |
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_btree.h"
#include "xfs_rmap_btree.h"
#include "xfs_trace.h"
#include "xfs_rmap.h"
#include "xfs_alloc.h"
#include "xfs_bit.h"
#include <linux/fsmap.h>
#include "xfs_fsmap.h"
#include "xfs_refcount.h"
#include "xfs_refcount_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_rtalloc.h"
#include "xfs_ag.h"
/* Convert an xfs_fsmap to an fsmap. */
static void
xfs_fsmap_from_internal(
struct fsmap *dest,
struct xfs_fsmap *src)
{
dest->fmr_device = src->fmr_device;
dest->fmr_flags = src->fmr_flags;
dest->fmr_physical = BBTOB(src->fmr_physical);
dest->fmr_owner = src->fmr_owner;
dest->fmr_offset = BBTOB(src->fmr_offset);
dest->fmr_length = BBTOB(src->fmr_length);
dest->fmr_reserved[0] = 0;
dest->fmr_reserved[1] = 0;
dest->fmr_reserved[2] = 0;
}
/* Convert an fsmap to an xfs_fsmap. */
void
xfs_fsmap_to_internal(
struct xfs_fsmap *dest,
struct fsmap *src)
{
dest->fmr_device = src->fmr_device;
dest->fmr_flags = src->fmr_flags;
dest->fmr_physical = BTOBBT(src->fmr_physical);
dest->fmr_owner = src->fmr_owner;
dest->fmr_offset = BTOBBT(src->fmr_offset);
dest->fmr_length = BTOBBT(src->fmr_length);
}
/* Convert an fsmap owner into an rmapbt owner. */
static int
xfs_fsmap_owner_to_rmap(
struct xfs_rmap_irec *dest,
const struct xfs_fsmap *src)
{
if (!(src->fmr_flags & FMR_OF_SPECIAL_OWNER)) {
dest->rm_owner = src->fmr_owner;
return 0;
}
switch (src->fmr_owner) {
case 0: /* "lowest owner id possible" */
case -1ULL: /* "highest owner id possible" */
dest->rm_owner = 0;
break;
case XFS_FMR_OWN_FREE:
dest->rm_owner = XFS_RMAP_OWN_NULL;
break;
case XFS_FMR_OWN_UNKNOWN:
dest->rm_owner = XFS_RMAP_OWN_UNKNOWN;
break;
case XFS_FMR_OWN_FS:
dest->rm_owner = XFS_RMAP_OWN_FS;
break;
case XFS_FMR_OWN_LOG:
dest->rm_owner = XFS_RMAP_OWN_LOG;
break;
case XFS_FMR_OWN_AG:
dest->rm_owner = XFS_RMAP_OWN_AG;
break;
case XFS_FMR_OWN_INOBT:
dest->rm_owner = XFS_RMAP_OWN_INOBT;
break;
case XFS_FMR_OWN_INODES:
dest->rm_owner = XFS_RMAP_OWN_INODES;
break;
case XFS_FMR_OWN_REFC:
dest->rm_owner = XFS_RMAP_OWN_REFC;
break;
case XFS_FMR_OWN_COW:
dest->rm_owner = XFS_RMAP_OWN_COW;
break;
case XFS_FMR_OWN_DEFECTIVE: /* not implemented */
/* fall through */
default:
return -EINVAL;
}
return 0;
}
/* Convert an rmapbt owner into an fsmap owner. */
static int
xfs_fsmap_owner_from_rmap(
struct xfs_fsmap *dest,
const struct xfs_rmap_irec *src)
{
dest->fmr_flags = 0;
if (!XFS_RMAP_NON_INODE_OWNER(src->rm_owner)) {
dest->fmr_owner = src->rm_owner;
return 0;
}
dest->fmr_flags |= FMR_OF_SPECIAL_OWNER;
switch (src->rm_owner) {
case XFS_RMAP_OWN_FS:
dest->fmr_owner = XFS_FMR_OWN_FS;
break;
case XFS_RMAP_OWN_LOG:
dest->fmr_owner = XFS_FMR_OWN_LOG;
break;
case XFS_RMAP_OWN_AG:
dest->fmr_owner = XFS_FMR_OWN_AG;
break;
case XFS_RMAP_OWN_INOBT:
dest->fmr_owner = XFS_FMR_OWN_INOBT;
break;
case XFS_RMAP_OWN_INODES:
dest->fmr_owner = XFS_FMR_OWN_INODES;
break;
case XFS_RMAP_OWN_REFC:
dest->fmr_owner = XFS_FMR_OWN_REFC;
break;
case XFS_RMAP_OWN_COW:
dest->fmr_owner = XFS_FMR_OWN_COW;
break;
case XFS_RMAP_OWN_NULL: /* "free" */
dest->fmr_owner = XFS_FMR_OWN_FREE;
break;
default:
ASSERT(0);
return -EFSCORRUPTED;
}
return 0;
}
/* getfsmap query state */
struct xfs_getfsmap_info {
struct xfs_fsmap_head *head;
struct fsmap *fsmap_recs; /* mapping records */
struct xfs_buf *agf_bp; /* AGF, for refcount queries */
struct xfs_perag *pag; /* AG info, if applicable */
xfs_daddr_t next_daddr; /* next daddr we expect */
/* daddr of low fsmap key when we're using the rtbitmap */
xfs_daddr_t low_daddr;
u64 missing_owner; /* owner of holes */
u32 dev; /* device id */
/*
* Low rmap key for the query. If low.rm_blockcount is nonzero, this
* is the second (or later) call to retrieve the recordset in pieces.
* xfs_getfsmap_rec_before_start will compare all records retrieved
* by the rmapbt query to filter out any records that start before
* the last record.
*/
struct xfs_rmap_irec low;
struct xfs_rmap_irec high; /* high rmap key */
bool last; /* last extent? */
};
/* Associate a device with a getfsmap handler. */
struct xfs_getfsmap_dev {
u32 dev;
int (*fn)(struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info);
};
/* Compare two getfsmap device handlers. */
static int
xfs_getfsmap_dev_compare(
const void *p1,
const void *p2)
{
const struct xfs_getfsmap_dev *d1 = p1;
const struct xfs_getfsmap_dev *d2 = p2;
return d1->dev - d2->dev;
}
/* Decide if this mapping is shared. */
STATIC int
xfs_getfsmap_is_shared(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
const struct xfs_rmap_irec *rec,
bool *stat)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_btree_cur *cur;
xfs_agblock_t fbno;
xfs_extlen_t flen;
int error;
*stat = false;
if (!xfs_has_reflink(mp))
return 0;
/* rt files will have no perag structure */
if (!info->pag)
return 0;
/* Are there any shared blocks here? */
flen = 0;
cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp, info->pag);
error = xfs_refcount_find_shared(cur, rec->rm_startblock,
rec->rm_blockcount, &fbno, &flen, false);
xfs_btree_del_cursor(cur, error);
if (error)
return error;
*stat = flen > 0;
return 0;
}
static inline void
xfs_getfsmap_format(
struct xfs_mount *mp,
struct xfs_fsmap *xfm,
struct xfs_getfsmap_info *info)
{
struct fsmap *rec;
trace_xfs_getfsmap_mapping(mp, xfm);
rec = &info->fsmap_recs[info->head->fmh_entries++];
xfs_fsmap_from_internal(rec, xfm);
}
static inline bool
xfs_getfsmap_rec_before_start(
struct xfs_getfsmap_info *info,
const struct xfs_rmap_irec *rec,
xfs_daddr_t rec_daddr)
{
if (info->low_daddr != -1ULL)
return rec_daddr < info->low_daddr;
if (info->low.rm_blockcount)
return xfs_rmap_compare(rec, &info->low) < 0;
return false;
}
/*
* Format a reverse mapping for getfsmap, having translated rm_startblock
* into the appropriate daddr units. Pass in a nonzero @len_daddr if the
* length could be larger than rm_blockcount in struct xfs_rmap_irec.
*/
STATIC int
xfs_getfsmap_helper(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
const struct xfs_rmap_irec *rec,
xfs_daddr_t rec_daddr,
xfs_daddr_t len_daddr)
{
struct xfs_fsmap fmr;
struct xfs_mount *mp = tp->t_mountp;
bool shared;
int error;
if (fatal_signal_pending(current))
return -EINTR;
if (len_daddr == 0)
len_daddr = XFS_FSB_TO_BB(mp, rec->rm_blockcount);
/*
* Filter out records that start before our startpoint, if the
* caller requested that.
*/
if (xfs_getfsmap_rec_before_start(info, rec, rec_daddr)) {
rec_daddr += len_daddr;
if (info->next_daddr < rec_daddr)
info->next_daddr = rec_daddr;
return 0;
}
/* Are we just counting mappings? */
if (info->head->fmh_count == 0) {
if (info->head->fmh_entries == UINT_MAX)
return -ECANCELED;
if (rec_daddr > info->next_daddr)
info->head->fmh_entries++;
if (info->last)
return 0;
info->head->fmh_entries++;
rec_daddr += len_daddr;
if (info->next_daddr < rec_daddr)
info->next_daddr = rec_daddr;
return 0;
}
/*
* If the record starts past the last physical block we saw,
* then we've found a gap. Report the gap as being owned by
* whatever the caller specified is the missing owner.
*/
if (rec_daddr > info->next_daddr) {
if (info->head->fmh_entries >= info->head->fmh_count)
return -ECANCELED;
fmr.fmr_device = info->dev;
fmr.fmr_physical = info->next_daddr;
fmr.fmr_owner = info->missing_owner;
fmr.fmr_offset = 0;
fmr.fmr_length = rec_daddr - info->next_daddr;
fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
xfs_getfsmap_format(mp, &fmr, info);
}
if (info->last)
goto out;
/* Fill out the extent we found */
if (info->head->fmh_entries >= info->head->fmh_count)
return -ECANCELED;
trace_xfs_fsmap_mapping(mp, info->dev,
info->pag ? info->pag->pag_agno : NULLAGNUMBER, rec);
fmr.fmr_device = info->dev;
fmr.fmr_physical = rec_daddr;
error = xfs_fsmap_owner_from_rmap(&fmr, rec);
if (error)
return error;
fmr.fmr_offset = XFS_FSB_TO_BB(mp, rec->rm_offset);
fmr.fmr_length = len_daddr;
if (rec->rm_flags & XFS_RMAP_UNWRITTEN)
fmr.fmr_flags |= FMR_OF_PREALLOC;
if (rec->rm_flags & XFS_RMAP_ATTR_FORK)
fmr.fmr_flags |= FMR_OF_ATTR_FORK;
if (rec->rm_flags & XFS_RMAP_BMBT_BLOCK)
fmr.fmr_flags |= FMR_OF_EXTENT_MAP;
if (fmr.fmr_flags == 0) {
error = xfs_getfsmap_is_shared(tp, info, rec, &shared);
if (error)
return error;
if (shared)
fmr.fmr_flags |= FMR_OF_SHARED;
}
xfs_getfsmap_format(mp, &fmr, info);
out:
rec_daddr += len_daddr;
if (info->next_daddr < rec_daddr)
info->next_daddr = rec_daddr;
return 0;
}
/* Transform a rmapbt irec into a fsmap */
STATIC int
xfs_getfsmap_datadev_helper(
struct xfs_btree_cur *cur,
const struct xfs_rmap_irec *rec,
void *priv)
{
struct xfs_mount *mp = cur->bc_mp;
struct xfs_getfsmap_info *info = priv;
xfs_fsblock_t fsb;
xfs_daddr_t rec_daddr;
fsb = XFS_AGB_TO_FSB(mp, cur->bc_ag.pag->pag_agno, rec->rm_startblock);
rec_daddr = XFS_FSB_TO_DADDR(mp, fsb);
return xfs_getfsmap_helper(cur->bc_tp, info, rec, rec_daddr, 0);
}
/* Transform a bnobt irec into a fsmap */
STATIC int
xfs_getfsmap_datadev_bnobt_helper(
struct xfs_btree_cur *cur,
const struct xfs_alloc_rec_incore *rec,
void *priv)
{
struct xfs_mount *mp = cur->bc_mp;
struct xfs_getfsmap_info *info = priv;
struct xfs_rmap_irec irec;
xfs_daddr_t rec_daddr;
rec_daddr = XFS_AGB_TO_DADDR(mp, cur->bc_ag.pag->pag_agno,
rec->ar_startblock);
irec.rm_startblock = rec->ar_startblock;
irec.rm_blockcount = rec->ar_blockcount;
irec.rm_owner = XFS_RMAP_OWN_NULL; /* "free" */
irec.rm_offset = 0;
irec.rm_flags = 0;
return xfs_getfsmap_helper(cur->bc_tp, info, &irec, rec_daddr, 0);
}
/* Set rmap flags based on the getfsmap flags */
static void
xfs_getfsmap_set_irec_flags(
struct xfs_rmap_irec *irec,
const struct xfs_fsmap *fmr)
{
irec->rm_flags = 0;
if (fmr->fmr_flags & FMR_OF_ATTR_FORK)
irec->rm_flags |= XFS_RMAP_ATTR_FORK;
if (fmr->fmr_flags & FMR_OF_EXTENT_MAP)
irec->rm_flags |= XFS_RMAP_BMBT_BLOCK;
if (fmr->fmr_flags & FMR_OF_PREALLOC)
irec->rm_flags |= XFS_RMAP_UNWRITTEN;
}
/* Execute a getfsmap query against the log device. */
STATIC int
xfs_getfsmap_logdev(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_rmap_irec rmap;
xfs_daddr_t rec_daddr, len_daddr;
xfs_fsblock_t start_fsb, end_fsb;
uint64_t eofs;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
if (keys[0].fmr_physical >= eofs)
return 0;
start_fsb = XFS_BB_TO_FSBT(mp,
keys[0].fmr_physical + keys[0].fmr_length);
end_fsb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
/* Adjust the low key if we are continuing from where we left off. */
if (keys[0].fmr_length > 0)
info->low_daddr = XFS_FSB_TO_BB(mp, start_fsb);
trace_xfs_fsmap_low_key_linear(mp, info->dev, start_fsb);
trace_xfs_fsmap_high_key_linear(mp, info->dev, end_fsb);
if (start_fsb > 0)
return 0;
/* Fabricate an rmap entry for the external log device. */
rmap.rm_startblock = 0;
rmap.rm_blockcount = mp->m_sb.sb_logblocks;
rmap.rm_owner = XFS_RMAP_OWN_LOG;
rmap.rm_offset = 0;
rmap.rm_flags = 0;
rec_daddr = XFS_FSB_TO_BB(mp, rmap.rm_startblock);
len_daddr = XFS_FSB_TO_BB(mp, rmap.rm_blockcount);
return xfs_getfsmap_helper(tp, info, &rmap, rec_daddr, len_daddr);
}
#ifdef CONFIG_XFS_RT
/* Transform a rtbitmap "record" into a fsmap */
STATIC int
xfs_getfsmap_rtdev_rtbitmap_helper(
struct xfs_mount *mp,
struct xfs_trans *tp,
const struct xfs_rtalloc_rec *rec,
void *priv)
{
struct xfs_getfsmap_info *info = priv;
struct xfs_rmap_irec irec;
xfs_rtblock_t rtbno;
xfs_daddr_t rec_daddr, len_daddr;
rtbno = rec->ar_startext * mp->m_sb.sb_rextsize;
rec_daddr = XFS_FSB_TO_BB(mp, rtbno);
irec.rm_startblock = rtbno;
rtbno = rec->ar_extcount * mp->m_sb.sb_rextsize;
len_daddr = XFS_FSB_TO_BB(mp, rtbno);
irec.rm_blockcount = rtbno;
irec.rm_owner = XFS_RMAP_OWN_NULL; /* "free" */
irec.rm_offset = 0;
irec.rm_flags = 0;
return xfs_getfsmap_helper(tp, info, &irec, rec_daddr, len_daddr);
}
/* Execute a getfsmap query against the realtime device rtbitmap. */
STATIC int
xfs_getfsmap_rtdev_rtbitmap(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
struct xfs_rtalloc_rec alow = { 0 };
struct xfs_rtalloc_rec ahigh = { 0 };
struct xfs_mount *mp = tp->t_mountp;
xfs_rtblock_t start_rtb;
xfs_rtblock_t end_rtb;
uint64_t eofs;
int error;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rextents * mp->m_sb.sb_rextsize);
if (keys[0].fmr_physical >= eofs)
return 0;
start_rtb = XFS_BB_TO_FSBT(mp,
keys[0].fmr_physical + keys[0].fmr_length);
end_rtb = XFS_BB_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
info->missing_owner = XFS_FMR_OWN_UNKNOWN;
/* Adjust the low key if we are continuing from where we left off. */
if (keys[0].fmr_length > 0) {
info->low_daddr = XFS_FSB_TO_BB(mp, start_rtb);
if (info->low_daddr >= eofs)
return 0;
}
trace_xfs_fsmap_low_key_linear(mp, info->dev, start_rtb);
trace_xfs_fsmap_high_key_linear(mp, info->dev, end_rtb);
xfs_ilock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
/*
* Set up query parameters to return free rtextents covering the range
* we want.
*/
alow.ar_startext = start_rtb;
ahigh.ar_startext = end_rtb;
do_div(alow.ar_startext, mp->m_sb.sb_rextsize);
if (do_div(ahigh.ar_startext, mp->m_sb.sb_rextsize))
ahigh.ar_startext++;
error = xfs_rtalloc_query_range(mp, tp, &alow, &ahigh,
xfs_getfsmap_rtdev_rtbitmap_helper, info);
if (error)
goto err;
/*
* Report any gaps at the end of the rtbitmap by simulating a null
* rmap starting at the block after the end of the query range.
*/
info->last = true;
ahigh.ar_startext = min(mp->m_sb.sb_rextents, ahigh.ar_startext);
error = xfs_getfsmap_rtdev_rtbitmap_helper(mp, tp, &ahigh, info);
if (error)
goto err;
err:
xfs_iunlock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
return error;
}
#endif /* CONFIG_XFS_RT */
static inline bool
rmap_not_shareable(struct xfs_mount *mp, const struct xfs_rmap_irec *r)
{
if (!xfs_has_reflink(mp))
return true;
if (XFS_RMAP_NON_INODE_OWNER(r->rm_owner))
return true;
if (r->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK |
XFS_RMAP_UNWRITTEN))
return true;
return false;
}
/* Execute a getfsmap query against the regular data device. */
STATIC int
__xfs_getfsmap_datadev(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info,
int (*query_fn)(struct xfs_trans *,
struct xfs_getfsmap_info *,
struct xfs_btree_cur **,
void *),
void *priv)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_perag *pag;
struct xfs_btree_cur *bt_cur = NULL;
xfs_fsblock_t start_fsb;
xfs_fsblock_t end_fsb;
xfs_agnumber_t start_ag;
xfs_agnumber_t end_ag;
uint64_t eofs;
int error = 0;
eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
if (keys[0].fmr_physical >= eofs)
return 0;
start_fsb = XFS_DADDR_TO_FSB(mp, keys[0].fmr_physical);
end_fsb = XFS_DADDR_TO_FSB(mp, min(eofs - 1, keys[1].fmr_physical));
/*
* Convert the fsmap low/high keys to AG based keys. Initialize
* low to the fsmap low key and max out the high key to the end
* of the AG.
*/
info->low.rm_offset = XFS_BB_TO_FSBT(mp, keys[0].fmr_offset);
error = xfs_fsmap_owner_to_rmap(&info->low, &keys[0]);
if (error)
return error;
info->low.rm_blockcount = XFS_BB_TO_FSBT(mp, keys[0].fmr_length);
xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);
/* Adjust the low key if we are continuing from where we left off. */
if (info->low.rm_blockcount == 0) {
/* No previous record from which to continue */
} else if (rmap_not_shareable(mp, &info->low)) {
/* Last record seen was an unshareable extent */
info->low.rm_owner = 0;
info->low.rm_offset = 0;
start_fsb += info->low.rm_blockcount;
if (XFS_FSB_TO_DADDR(mp, start_fsb) >= eofs)
return 0;
} else {
/* Last record seen was a shareable file data extent */
info->low.rm_offset += info->low.rm_blockcount;
}
info->low.rm_startblock = XFS_FSB_TO_AGBNO(mp, start_fsb);
info->high.rm_startblock = -1U;
info->high.rm_owner = ULLONG_MAX;
info->high.rm_offset = ULLONG_MAX;
info->high.rm_blockcount = 0;
info->high.rm_flags = XFS_RMAP_KEY_FLAGS | XFS_RMAP_REC_FLAGS;
start_ag = XFS_FSB_TO_AGNO(mp, start_fsb);
end_ag = XFS_FSB_TO_AGNO(mp, end_fsb);
for_each_perag_range(mp, start_ag, end_ag, pag) {
/*
* Set the AG high key from the fsmap high key if this
* is the last AG that we're querying.
*/
info->pag = pag;
if (pag->pag_agno == end_ag) {
info->high.rm_startblock = XFS_FSB_TO_AGBNO(mp,
end_fsb);
info->high.rm_offset = XFS_BB_TO_FSBT(mp,
keys[1].fmr_offset);
error = xfs_fsmap_owner_to_rmap(&info->high, &keys[1]);
if (error)
break;
xfs_getfsmap_set_irec_flags(&info->high, &keys[1]);
}
if (bt_cur) {
xfs_btree_del_cursor(bt_cur, XFS_BTREE_NOERROR);
bt_cur = NULL;
xfs_trans_brelse(tp, info->agf_bp);
info->agf_bp = NULL;
}
error = xfs_alloc_read_agf(pag, tp, 0, &info->agf_bp);
if (error)
break;
trace_xfs_fsmap_low_key(mp, info->dev, pag->pag_agno,
&info->low);
trace_xfs_fsmap_high_key(mp, info->dev, pag->pag_agno,
&info->high);
error = query_fn(tp, info, &bt_cur, priv);
if (error)
break;
/*
* Set the AG low key to the start of the AG prior to
* moving on to the next AG.
*/
if (pag->pag_agno == start_ag)
memset(&info->low, 0, sizeof(info->low));
/*
* If this is the last AG, report any gap at the end of it
* before we drop the reference to the perag when the loop
* terminates.
*/
if (pag->pag_agno == end_ag) {
info->last = true;
error = query_fn(tp, info, &bt_cur, priv);
if (error)
break;
}
info->pag = NULL;
}
if (bt_cur)
xfs_btree_del_cursor(bt_cur, error < 0 ? XFS_BTREE_ERROR :
XFS_BTREE_NOERROR);
if (info->agf_bp) {
xfs_trans_brelse(tp, info->agf_bp);
info->agf_bp = NULL;
}
if (info->pag) {
xfs_perag_rele(info->pag);
info->pag = NULL;
} else if (pag) {
/* loop termination case */
xfs_perag_rele(pag);
}
return error;
}
/* Actually query the rmap btree. */
STATIC int
xfs_getfsmap_datadev_rmapbt_query(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
struct xfs_btree_cur **curpp,
void *priv)
{
/* Report any gap at the end of the last AG. */
if (info->last)
return xfs_getfsmap_datadev_helper(*curpp, &info->high, info);
/* Allocate cursor for this AG and query_range it. */
*curpp = xfs_rmapbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
info->pag);
return xfs_rmap_query_range(*curpp, &info->low, &info->high,
xfs_getfsmap_datadev_helper, info);
}
/* Execute a getfsmap query against the regular data device rmapbt. */
STATIC int
xfs_getfsmap_datadev_rmapbt(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
info->missing_owner = XFS_FMR_OWN_FREE;
return __xfs_getfsmap_datadev(tp, keys, info,
xfs_getfsmap_datadev_rmapbt_query, NULL);
}
/* Actually query the bno btree. */
STATIC int
xfs_getfsmap_datadev_bnobt_query(
struct xfs_trans *tp,
struct xfs_getfsmap_info *info,
struct xfs_btree_cur **curpp,
void *priv)
{
struct xfs_alloc_rec_incore *key = priv;
/* Report any gap at the end of the last AG. */
if (info->last)
return xfs_getfsmap_datadev_bnobt_helper(*curpp, &key[1], info);
/* Allocate cursor for this AG and query_range it. */
*curpp = xfs_allocbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
info->pag, XFS_BTNUM_BNO);
key->ar_startblock = info->low.rm_startblock;
key[1].ar_startblock = info->high.rm_startblock;
return xfs_alloc_query_range(*curpp, key, &key[1],
xfs_getfsmap_datadev_bnobt_helper, info);
}
/* Execute a getfsmap query against the regular data device's bnobt. */
STATIC int
xfs_getfsmap_datadev_bnobt(
struct xfs_trans *tp,
const struct xfs_fsmap *keys,
struct xfs_getfsmap_info *info)
{
struct xfs_alloc_rec_incore akeys[2];
memset(akeys, 0, sizeof(akeys));
info->missing_owner = XFS_FMR_OWN_UNKNOWN;
return __xfs_getfsmap_datadev(tp, keys, info,
xfs_getfsmap_datadev_bnobt_query, &akeys[0]);
}
/* Do we recognize the device? */
STATIC bool
xfs_getfsmap_is_valid_device(
struct xfs_mount *mp,
struct xfs_fsmap *fm)
{
if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
fm->fmr_device == new_encode_dev(mp->m_ddev_targp->bt_dev))
return true;
if (mp->m_logdev_targp &&
fm->fmr_device == new_encode_dev(mp->m_logdev_targp->bt_dev))
return true;
if (mp->m_rtdev_targp &&
fm->fmr_device == new_encode_dev(mp->m_rtdev_targp->bt_dev))
return true;
return false;
}
/* Ensure that the low key is less than the high key. */
STATIC bool
xfs_getfsmap_check_keys(
struct xfs_fsmap *low_key,
struct xfs_fsmap *high_key)
{
if (low_key->fmr_flags & (FMR_OF_SPECIAL_OWNER | FMR_OF_EXTENT_MAP)) {
if (low_key->fmr_offset)
return false;
}
if (high_key->fmr_flags != -1U &&
(high_key->fmr_flags & (FMR_OF_SPECIAL_OWNER |
FMR_OF_EXTENT_MAP))) {
if (high_key->fmr_offset && high_key->fmr_offset != -1ULL)
return false;
}
if (high_key->fmr_length && high_key->fmr_length != -1ULL)
return false;
if (low_key->fmr_device > high_key->fmr_device)
return false;
if (low_key->fmr_device < high_key->fmr_device)
return true;
if (low_key->fmr_physical > high_key->fmr_physical)
return false;
if (low_key->fmr_physical < high_key->fmr_physical)
return true;
if (low_key->fmr_owner > high_key->fmr_owner)
return false;
if (low_key->fmr_owner < high_key->fmr_owner)
return true;
if (low_key->fmr_offset > high_key->fmr_offset)
return false;
if (low_key->fmr_offset < high_key->fmr_offset)
return true;
return false;
}
/*
* There are only two devices if we didn't configure RT devices at build time.
*/
#ifdef CONFIG_XFS_RT
#define XFS_GETFSMAP_DEVS 3
#else
#define XFS_GETFSMAP_DEVS 2
#endif /* CONFIG_XFS_RT */
/*
* Get filesystem's extents as described in head, and format for output. Fills
* in the supplied records array until there are no more reverse mappings to
* return or head.fmh_entries == head.fmh_count. In the second case, this
* function returns -ECANCELED to indicate that more records would have been
* returned.
*
* Key to Confusion
* ----------------
* There are multiple levels of keys and counters at work here:
* xfs_fsmap_head.fmh_keys -- low and high fsmap keys passed in;
* these reflect fs-wide sector addrs.
* dkeys -- fmh_keys used to query each device;
* these are fmh_keys but w/ the low key
* bumped up by fmr_length.
* xfs_getfsmap_info.next_daddr -- next disk addr we expect to see; this
* is how we detect gaps in the fsmap
records and report them.
* xfs_getfsmap_info.low/high -- per-AG low/high keys computed from
* dkeys; used to query the metadata.
*/
int
xfs_getfsmap(
struct xfs_mount *mp,
struct xfs_fsmap_head *head,
struct fsmap *fsmap_recs)
{
struct xfs_trans *tp = NULL;
struct xfs_fsmap dkeys[2]; /* per-dev keys */
struct xfs_getfsmap_dev handlers[XFS_GETFSMAP_DEVS];
struct xfs_getfsmap_info info = { NULL };
bool use_rmap;
int i;
int error = 0;
if (head->fmh_iflags & ~FMH_IF_VALID)
return -EINVAL;
if (!xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[0]) ||
!xfs_getfsmap_is_valid_device(mp, &head->fmh_keys[1]))
return -EINVAL;
if (!xfs_getfsmap_check_keys(&head->fmh_keys[0], &head->fmh_keys[1]))
return -EINVAL;
use_rmap = xfs_has_rmapbt(mp) &&
has_capability_noaudit(current, CAP_SYS_ADMIN);
head->fmh_entries = 0;
/* Set up our device handlers. */
memset(handlers, 0, sizeof(handlers));
handlers[0].dev = new_encode_dev(mp->m_ddev_targp->bt_dev);
if (use_rmap)
handlers[0].fn = xfs_getfsmap_datadev_rmapbt;
else
handlers[0].fn = xfs_getfsmap_datadev_bnobt;
if (mp->m_logdev_targp != mp->m_ddev_targp) {
handlers[1].dev = new_encode_dev(mp->m_logdev_targp->bt_dev);
handlers[1].fn = xfs_getfsmap_logdev;
}
#ifdef CONFIG_XFS_RT
if (mp->m_rtdev_targp) {
handlers[2].dev = new_encode_dev(mp->m_rtdev_targp->bt_dev);
handlers[2].fn = xfs_getfsmap_rtdev_rtbitmap;
}
#endif /* CONFIG_XFS_RT */
xfs_sort(handlers, XFS_GETFSMAP_DEVS, sizeof(struct xfs_getfsmap_dev),
xfs_getfsmap_dev_compare);
/*
* To continue where we left off, we allow userspace to use the
* last mapping from a previous call as the low key of the next.
* This is identified by a non-zero length in the low key. We
* have to increment the low key in this scenario to ensure we
* don't return the same mapping again, and instead return the
* very next mapping.
*
* If the low key mapping refers to file data, the same physical
* blocks could be mapped to several other files/offsets.
* According to rmapbt record ordering, the minimal next
* possible record for the block range is the next starting
* offset in the same inode. Therefore, each fsmap backend bumps
* the file offset to continue the search appropriately. For
* all other low key mapping types (attr blocks, metadata), each
* fsmap backend bumps the physical offset as there can be no
* other mapping for the same physical block range.
*/
dkeys[0] = head->fmh_keys[0];
memset(&dkeys[1], 0xFF, sizeof(struct xfs_fsmap));
info.next_daddr = head->fmh_keys[0].fmr_physical +
head->fmh_keys[0].fmr_length;
info.fsmap_recs = fsmap_recs;
info.head = head;
/* For each device we support... */
for (i = 0; i < XFS_GETFSMAP_DEVS; i++) {
/* Is this device within the range the user asked for? */
if (!handlers[i].fn)
continue;
if (head->fmh_keys[0].fmr_device > handlers[i].dev)
continue;
if (head->fmh_keys[1].fmr_device < handlers[i].dev)
break;
/*
* If this device number matches the high key, we have
* to pass the high key to the handler to limit the
* query results. If the device number exceeds the
* low key, zero out the low key so that we get
* everything from the beginning.
*/
if (handlers[i].dev == head->fmh_keys[1].fmr_device)
dkeys[1] = head->fmh_keys[1];
if (handlers[i].dev > head->fmh_keys[0].fmr_device)
memset(&dkeys[0], 0, sizeof(struct xfs_fsmap));
/*
* Grab an empty transaction so that we can use its recursive
* buffer locking abilities to detect cycles in the rmapbt
* without deadlocking.
*/
error = xfs_trans_alloc_empty(mp, &tp);
if (error)
break;
info.dev = handlers[i].dev;
info.last = false;
info.pag = NULL;
info.low_daddr = -1ULL;
info.low.rm_blockcount = 0;
error = handlers[i].fn(tp, dkeys, &info);
if (error)
break;
xfs_trans_cancel(tp);
tp = NULL;
info.next_daddr = 0;
}
if (tp)
xfs_trans_cancel(tp);
head->fmh_oflags = FMH_OF_DEV_T;
return error;
}
| linux-master | fs/xfs/xfs_fsmap.c |
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2016 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_shared.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_rmap_item.h"
#include "xfs_log.h"
#include "xfs_rmap.h"
#include "xfs_error.h"
#include "xfs_log_priv.h"
#include "xfs_log_recover.h"
#include "xfs_ag.h"
struct kmem_cache *xfs_rui_cache;
struct kmem_cache *xfs_rud_cache;
static const struct xfs_item_ops xfs_rui_item_ops;
static inline struct xfs_rui_log_item *RUI_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_rui_log_item, rui_item);
}
STATIC void
xfs_rui_item_free(
struct xfs_rui_log_item *ruip)
{
kmem_free(ruip->rui_item.li_lv_shadow);
if (ruip->rui_format.rui_nextents > XFS_RUI_MAX_FAST_EXTENTS)
kmem_free(ruip);
else
kmem_cache_free(xfs_rui_cache, ruip);
}
/*
* Freeing the RUI requires that we remove it from the AIL if it has already
* been placed there. However, the RUI may not yet have been placed in the AIL
* when called by xfs_rui_release() from RUD processing due to the ordering of
* committed vs unpin operations in bulk insert operations. Hence the reference
* count to ensure only the last caller frees the RUI.
*/
STATIC void
xfs_rui_release(
struct xfs_rui_log_item *ruip)
{
ASSERT(atomic_read(&ruip->rui_refcount) > 0);
if (!atomic_dec_and_test(&ruip->rui_refcount))
return;
xfs_trans_ail_delete(&ruip->rui_item, 0);
xfs_rui_item_free(ruip);
}
STATIC void
xfs_rui_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
struct xfs_rui_log_item *ruip = RUI_ITEM(lip);
*nvecs += 1;
*nbytes += xfs_rui_log_format_sizeof(ruip->rui_format.rui_nextents);
}
/*
* This is called to fill in the vector of log iovecs for the
* given rui log item. We use only 1 iovec, and we point that
* at the rui_log_format structure embedded in the rui item.
* It is at this point that we assert that all of the extent
* slots in the rui item have been filled.
*/
STATIC void
xfs_rui_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_rui_log_item *ruip = RUI_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
ASSERT(atomic_read(&ruip->rui_next_extent) ==
ruip->rui_format.rui_nextents);
ruip->rui_format.rui_type = XFS_LI_RUI;
ruip->rui_format.rui_size = 1;
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_RUI_FORMAT, &ruip->rui_format,
xfs_rui_log_format_sizeof(ruip->rui_format.rui_nextents));
}
/*
* The unpin operation is the last place an RUI is manipulated in the log. It is
* either inserted in the AIL or aborted in the event of a log I/O error. In
* either case, the RUI transaction has been successfully committed to make it
* this far. Therefore, we expect whoever committed the RUI to either construct
* and commit the RUD or drop the RUD's reference in the event of error. Simply
* drop the log's RUI reference now that the log is done with it.
*/
STATIC void
xfs_rui_item_unpin(
struct xfs_log_item *lip,
int remove)
{
struct xfs_rui_log_item *ruip = RUI_ITEM(lip);
xfs_rui_release(ruip);
}
/*
* The RUI has been either committed or aborted if the transaction has been
* cancelled. If the transaction was cancelled, an RUD isn't going to be
* constructed and thus we free the RUI here directly.
*/
STATIC void
xfs_rui_item_release(
struct xfs_log_item *lip)
{
xfs_rui_release(RUI_ITEM(lip));
}
/*
* Allocate and initialize an rui item with the given number of extents.
*/
STATIC struct xfs_rui_log_item *
xfs_rui_init(
struct xfs_mount *mp,
uint nextents)
{
struct xfs_rui_log_item *ruip;
ASSERT(nextents > 0);
if (nextents > XFS_RUI_MAX_FAST_EXTENTS)
ruip = kmem_zalloc(xfs_rui_log_item_sizeof(nextents), 0);
else
ruip = kmem_cache_zalloc(xfs_rui_cache,
GFP_KERNEL | __GFP_NOFAIL);
xfs_log_item_init(mp, &ruip->rui_item, XFS_LI_RUI, &xfs_rui_item_ops);
ruip->rui_format.rui_nextents = nextents;
ruip->rui_format.rui_id = (uintptr_t)(void *)ruip;
atomic_set(&ruip->rui_next_extent, 0);
atomic_set(&ruip->rui_refcount, 2);
return ruip;
}
static inline struct xfs_rud_log_item *RUD_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_rud_log_item, rud_item);
}
STATIC void
xfs_rud_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
*nvecs += 1;
*nbytes += sizeof(struct xfs_rud_log_format);
}
/*
* This is called to fill in the vector of log iovecs for the
* given rud log item. We use only 1 iovec, and we point that
* at the rud_log_format structure embedded in the rud item.
* It is at this point that we assert that all of the extent
* slots in the rud item have been filled.
*/
STATIC void
xfs_rud_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_rud_log_item *rudp = RUD_ITEM(lip);
struct xfs_log_iovec *vecp = NULL;
rudp->rud_format.rud_type = XFS_LI_RUD;
rudp->rud_format.rud_size = 1;
xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_RUD_FORMAT, &rudp->rud_format,
sizeof(struct xfs_rud_log_format));
}
/*
* The RUD is either committed or aborted if the transaction is cancelled. If
* the transaction is cancelled, drop our reference to the RUI and free the
* RUD.
*/
STATIC void
xfs_rud_item_release(
struct xfs_log_item *lip)
{
struct xfs_rud_log_item *rudp = RUD_ITEM(lip);
xfs_rui_release(rudp->rud_ruip);
kmem_free(rudp->rud_item.li_lv_shadow);
kmem_cache_free(xfs_rud_cache, rudp);
}
static struct xfs_log_item *
xfs_rud_item_intent(
struct xfs_log_item *lip)
{
return &RUD_ITEM(lip)->rud_ruip->rui_item;
}
static const struct xfs_item_ops xfs_rud_item_ops = {
.flags = XFS_ITEM_RELEASE_WHEN_COMMITTED |
XFS_ITEM_INTENT_DONE,
.iop_size = xfs_rud_item_size,
.iop_format = xfs_rud_item_format,
.iop_release = xfs_rud_item_release,
.iop_intent = xfs_rud_item_intent,
};
static struct xfs_rud_log_item *
xfs_trans_get_rud(
struct xfs_trans *tp,
struct xfs_rui_log_item *ruip)
{
struct xfs_rud_log_item *rudp;
rudp = kmem_cache_zalloc(xfs_rud_cache, GFP_KERNEL | __GFP_NOFAIL);
xfs_log_item_init(tp->t_mountp, &rudp->rud_item, XFS_LI_RUD,
&xfs_rud_item_ops);
rudp->rud_ruip = ruip;
rudp->rud_format.rud_rui_id = ruip->rui_format.rui_id;
xfs_trans_add_item(tp, &rudp->rud_item);
return rudp;
}
/* Set the map extent flags for this reverse mapping. */
static void
xfs_trans_set_rmap_flags(
struct xfs_map_extent *map,
enum xfs_rmap_intent_type type,
int whichfork,
xfs_exntst_t state)
{
map->me_flags = 0;
if (state == XFS_EXT_UNWRITTEN)
map->me_flags |= XFS_RMAP_EXTENT_UNWRITTEN;
if (whichfork == XFS_ATTR_FORK)
map->me_flags |= XFS_RMAP_EXTENT_ATTR_FORK;
switch (type) {
case XFS_RMAP_MAP:
map->me_flags |= XFS_RMAP_EXTENT_MAP;
break;
case XFS_RMAP_MAP_SHARED:
map->me_flags |= XFS_RMAP_EXTENT_MAP_SHARED;
break;
case XFS_RMAP_UNMAP:
map->me_flags |= XFS_RMAP_EXTENT_UNMAP;
break;
case XFS_RMAP_UNMAP_SHARED:
map->me_flags |= XFS_RMAP_EXTENT_UNMAP_SHARED;
break;
case XFS_RMAP_CONVERT:
map->me_flags |= XFS_RMAP_EXTENT_CONVERT;
break;
case XFS_RMAP_CONVERT_SHARED:
map->me_flags |= XFS_RMAP_EXTENT_CONVERT_SHARED;
break;
case XFS_RMAP_ALLOC:
map->me_flags |= XFS_RMAP_EXTENT_ALLOC;
break;
case XFS_RMAP_FREE:
map->me_flags |= XFS_RMAP_EXTENT_FREE;
break;
default:
ASSERT(0);
}
}
/*
* Finish an rmap update and log it to the RUD. Note that the transaction is
* marked dirty regardless of whether the rmap update succeeds or fails to
* support the RUI/RUD lifecycle rules.
*/
static int
xfs_trans_log_finish_rmap_update(
struct xfs_trans *tp,
struct xfs_rud_log_item *rudp,
struct xfs_rmap_intent *ri,
struct xfs_btree_cur **pcur)
{
int error;
error = xfs_rmap_finish_one(tp, ri, pcur);
/*
* Mark the transaction dirty, even on error. This ensures the
* transaction is aborted, which:
*
* 1.) releases the RUI and frees the RUD
* 2.) shuts down the filesystem
*/
tp->t_flags |= XFS_TRANS_DIRTY | XFS_TRANS_HAS_INTENT_DONE;
set_bit(XFS_LI_DIRTY, &rudp->rud_item.li_flags);
return error;
}
/* Sort rmap intents by AG. */
static int
xfs_rmap_update_diff_items(
void *priv,
const struct list_head *a,
const struct list_head *b)
{
struct xfs_rmap_intent *ra;
struct xfs_rmap_intent *rb;
ra = container_of(a, struct xfs_rmap_intent, ri_list);
rb = container_of(b, struct xfs_rmap_intent, ri_list);
return ra->ri_pag->pag_agno - rb->ri_pag->pag_agno;
}
/* Log rmap updates in the intent item. */
STATIC void
xfs_rmap_update_log_item(
struct xfs_trans *tp,
struct xfs_rui_log_item *ruip,
struct xfs_rmap_intent *ri)
{
uint next_extent;
struct xfs_map_extent *map;
tp->t_flags |= XFS_TRANS_DIRTY;
set_bit(XFS_LI_DIRTY, &ruip->rui_item.li_flags);
/*
* atomic_inc_return gives us the value after the increment;
* we want to use it as an array index so we need to subtract 1 from
* it.
*/
next_extent = atomic_inc_return(&ruip->rui_next_extent) - 1;
ASSERT(next_extent < ruip->rui_format.rui_nextents);
map = &ruip->rui_format.rui_extents[next_extent];
map->me_owner = ri->ri_owner;
map->me_startblock = ri->ri_bmap.br_startblock;
map->me_startoff = ri->ri_bmap.br_startoff;
map->me_len = ri->ri_bmap.br_blockcount;
xfs_trans_set_rmap_flags(map, ri->ri_type, ri->ri_whichfork,
ri->ri_bmap.br_state);
}
static struct xfs_log_item *
xfs_rmap_update_create_intent(
struct xfs_trans *tp,
struct list_head *items,
unsigned int count,
bool sort)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_rui_log_item *ruip = xfs_rui_init(mp, count);
struct xfs_rmap_intent *ri;
ASSERT(count > 0);
xfs_trans_add_item(tp, &ruip->rui_item);
if (sort)
list_sort(mp, items, xfs_rmap_update_diff_items);
list_for_each_entry(ri, items, ri_list)
xfs_rmap_update_log_item(tp, ruip, ri);
return &ruip->rui_item;
}
/* Get an RUD so we can process all the deferred rmap updates. */
static struct xfs_log_item *
xfs_rmap_update_create_done(
struct xfs_trans *tp,
struct xfs_log_item *intent,
unsigned int count)
{
return &xfs_trans_get_rud(tp, RUI_ITEM(intent))->rud_item;
}
/* Take a passive ref to the AG containing the space we're rmapping. */
void
xfs_rmap_update_get_group(
struct xfs_mount *mp,
struct xfs_rmap_intent *ri)
{
xfs_agnumber_t agno;
agno = XFS_FSB_TO_AGNO(mp, ri->ri_bmap.br_startblock);
ri->ri_pag = xfs_perag_intent_get(mp, agno);
}
/* Release a passive AG ref after finishing rmapping work. */
static inline void
xfs_rmap_update_put_group(
struct xfs_rmap_intent *ri)
{
xfs_perag_intent_put(ri->ri_pag);
}
/* Process a deferred rmap update. */
STATIC int
xfs_rmap_update_finish_item(
struct xfs_trans *tp,
struct xfs_log_item *done,
struct list_head *item,
struct xfs_btree_cur **state)
{
struct xfs_rmap_intent *ri;
int error;
ri = container_of(item, struct xfs_rmap_intent, ri_list);
error = xfs_trans_log_finish_rmap_update(tp, RUD_ITEM(done), ri,
state);
xfs_rmap_update_put_group(ri);
kmem_cache_free(xfs_rmap_intent_cache, ri);
return error;
}
/* Abort all pending RUIs. */
STATIC void
xfs_rmap_update_abort_intent(
struct xfs_log_item *intent)
{
xfs_rui_release(RUI_ITEM(intent));
}
/* Cancel a deferred rmap update. */
STATIC void
xfs_rmap_update_cancel_item(
struct list_head *item)
{
struct xfs_rmap_intent *ri;
ri = container_of(item, struct xfs_rmap_intent, ri_list);
xfs_rmap_update_put_group(ri);
kmem_cache_free(xfs_rmap_intent_cache, ri);
}
const struct xfs_defer_op_type xfs_rmap_update_defer_type = {
.max_items = XFS_RUI_MAX_FAST_EXTENTS,
.create_intent = xfs_rmap_update_create_intent,
.abort_intent = xfs_rmap_update_abort_intent,
.create_done = xfs_rmap_update_create_done,
.finish_item = xfs_rmap_update_finish_item,
.finish_cleanup = xfs_rmap_finish_one_cleanup,
.cancel_item = xfs_rmap_update_cancel_item,
};
/* Is this recovered RUI ok? */
static inline bool
xfs_rui_validate_map(
struct xfs_mount *mp,
struct xfs_map_extent *map)
{
if (!xfs_has_rmapbt(mp))
return false;
if (map->me_flags & ~XFS_RMAP_EXTENT_FLAGS)
return false;
switch (map->me_flags & XFS_RMAP_EXTENT_TYPE_MASK) {
case XFS_RMAP_EXTENT_MAP:
case XFS_RMAP_EXTENT_MAP_SHARED:
case XFS_RMAP_EXTENT_UNMAP:
case XFS_RMAP_EXTENT_UNMAP_SHARED:
case XFS_RMAP_EXTENT_CONVERT:
case XFS_RMAP_EXTENT_CONVERT_SHARED:
case XFS_RMAP_EXTENT_ALLOC:
case XFS_RMAP_EXTENT_FREE:
break;
default:
return false;
}
if (!XFS_RMAP_NON_INODE_OWNER(map->me_owner) &&
!xfs_verify_ino(mp, map->me_owner))
return false;
if (!xfs_verify_fileext(mp, map->me_startoff, map->me_len))
return false;
return xfs_verify_fsbext(mp, map->me_startblock, map->me_len);
}
/*
* Process an rmap update intent item that was recovered from the log.
* We need to update the rmapbt.
*/
STATIC int
xfs_rui_item_recover(
struct xfs_log_item *lip,
struct list_head *capture_list)
{
struct xfs_trans_res resv;
struct xfs_rui_log_item *ruip = RUI_ITEM(lip);
struct xfs_rud_log_item *rudp;
struct xfs_trans *tp;
struct xfs_btree_cur *rcur = NULL;
struct xfs_mount *mp = lip->li_log->l_mp;
int i;
int error = 0;
/*
* First check the validity of the extents described by the
* RUI. If any are bad, then assume that all are bad and
* just toss the RUI.
*/
for (i = 0; i < ruip->rui_format.rui_nextents; i++) {
if (!xfs_rui_validate_map(mp,
&ruip->rui_format.rui_extents[i])) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
&ruip->rui_format,
sizeof(ruip->rui_format));
return -EFSCORRUPTED;
}
}
resv = xlog_recover_resv(&M_RES(mp)->tr_itruncate);
error = xfs_trans_alloc(mp, &resv, mp->m_rmap_maxlevels, 0,
XFS_TRANS_RESERVE, &tp);
if (error)
return error;
rudp = xfs_trans_get_rud(tp, ruip);
for (i = 0; i < ruip->rui_format.rui_nextents; i++) {
struct xfs_rmap_intent fake = { };
struct xfs_map_extent *map;
map = &ruip->rui_format.rui_extents[i];
switch (map->me_flags & XFS_RMAP_EXTENT_TYPE_MASK) {
case XFS_RMAP_EXTENT_MAP:
fake.ri_type = XFS_RMAP_MAP;
break;
case XFS_RMAP_EXTENT_MAP_SHARED:
fake.ri_type = XFS_RMAP_MAP_SHARED;
break;
case XFS_RMAP_EXTENT_UNMAP:
fake.ri_type = XFS_RMAP_UNMAP;
break;
case XFS_RMAP_EXTENT_UNMAP_SHARED:
fake.ri_type = XFS_RMAP_UNMAP_SHARED;
break;
case XFS_RMAP_EXTENT_CONVERT:
fake.ri_type = XFS_RMAP_CONVERT;
break;
case XFS_RMAP_EXTENT_CONVERT_SHARED:
fake.ri_type = XFS_RMAP_CONVERT_SHARED;
break;
case XFS_RMAP_EXTENT_ALLOC:
fake.ri_type = XFS_RMAP_ALLOC;
break;
case XFS_RMAP_EXTENT_FREE:
fake.ri_type = XFS_RMAP_FREE;
break;
default:
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
&ruip->rui_format,
sizeof(ruip->rui_format));
error = -EFSCORRUPTED;
goto abort_error;
}
fake.ri_owner = map->me_owner;
fake.ri_whichfork = (map->me_flags & XFS_RMAP_EXTENT_ATTR_FORK) ?
XFS_ATTR_FORK : XFS_DATA_FORK;
fake.ri_bmap.br_startblock = map->me_startblock;
fake.ri_bmap.br_startoff = map->me_startoff;
fake.ri_bmap.br_blockcount = map->me_len;
fake.ri_bmap.br_state = (map->me_flags & XFS_RMAP_EXTENT_UNWRITTEN) ?
XFS_EXT_UNWRITTEN : XFS_EXT_NORM;
xfs_rmap_update_get_group(mp, &fake);
error = xfs_trans_log_finish_rmap_update(tp, rudp, &fake,
&rcur);
if (error == -EFSCORRUPTED)
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
map, sizeof(*map));
xfs_rmap_update_put_group(&fake);
if (error)
goto abort_error;
}
xfs_rmap_finish_one_cleanup(tp, rcur, error);
return xfs_defer_ops_capture_and_commit(tp, capture_list);
abort_error:
xfs_rmap_finish_one_cleanup(tp, rcur, error);
xfs_trans_cancel(tp);
return error;
}
STATIC bool
xfs_rui_item_match(
struct xfs_log_item *lip,
uint64_t intent_id)
{
return RUI_ITEM(lip)->rui_format.rui_id == intent_id;
}
/* Relog an intent item to push the log tail forward. */
static struct xfs_log_item *
xfs_rui_item_relog(
struct xfs_log_item *intent,
struct xfs_trans *tp)
{
struct xfs_rud_log_item *rudp;
struct xfs_rui_log_item *ruip;
struct xfs_map_extent *map;
unsigned int count;
count = RUI_ITEM(intent)->rui_format.rui_nextents;
map = RUI_ITEM(intent)->rui_format.rui_extents;
tp->t_flags |= XFS_TRANS_DIRTY;
rudp = xfs_trans_get_rud(tp, RUI_ITEM(intent));
set_bit(XFS_LI_DIRTY, &rudp->rud_item.li_flags);
ruip = xfs_rui_init(tp->t_mountp, count);
memcpy(ruip->rui_format.rui_extents, map, count * sizeof(*map));
atomic_set(&ruip->rui_next_extent, count);
xfs_trans_add_item(tp, &ruip->rui_item);
set_bit(XFS_LI_DIRTY, &ruip->rui_item.li_flags);
return &ruip->rui_item;
}
static const struct xfs_item_ops xfs_rui_item_ops = {
.flags = XFS_ITEM_INTENT,
.iop_size = xfs_rui_item_size,
.iop_format = xfs_rui_item_format,
.iop_unpin = xfs_rui_item_unpin,
.iop_release = xfs_rui_item_release,
.iop_recover = xfs_rui_item_recover,
.iop_match = xfs_rui_item_match,
.iop_relog = xfs_rui_item_relog,
};
static inline void
xfs_rui_copy_format(
struct xfs_rui_log_format *dst,
const struct xfs_rui_log_format *src)
{
unsigned int i;
memcpy(dst, src, offsetof(struct xfs_rui_log_format, rui_extents));
for (i = 0; i < src->rui_nextents; i++)
memcpy(&dst->rui_extents[i], &src->rui_extents[i],
sizeof(struct xfs_map_extent));
}
/*
* This routine is called to create an in-core extent rmap update
* item from the rui format structure which was logged on disk.
* It allocates an in-core rui, copies the extents from the format
* structure into it, and adds the rui to the AIL with the given
* LSN.
*/
STATIC int
xlog_recover_rui_commit_pass2(
struct xlog *log,
struct list_head *buffer_list,
struct xlog_recover_item *item,
xfs_lsn_t lsn)
{
struct xfs_mount *mp = log->l_mp;
struct xfs_rui_log_item *ruip;
struct xfs_rui_log_format *rui_formatp;
size_t len;
rui_formatp = item->ri_buf[0].i_addr;
if (item->ri_buf[0].i_len < xfs_rui_log_format_sizeof(0)) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
item->ri_buf[0].i_addr, item->ri_buf[0].i_len);
return -EFSCORRUPTED;
}
len = xfs_rui_log_format_sizeof(rui_formatp->rui_nextents);
if (item->ri_buf[0].i_len != len) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
item->ri_buf[0].i_addr, item->ri_buf[0].i_len);
return -EFSCORRUPTED;
}
ruip = xfs_rui_init(mp, rui_formatp->rui_nextents);
xfs_rui_copy_format(&ruip->rui_format, rui_formatp);
atomic_set(&ruip->rui_next_extent, rui_formatp->rui_nextents);
/*
* Insert the intent into the AIL directly and drop one reference so
* that finishing or canceling the work will drop the other.
*/
xfs_trans_ail_insert(log->l_ailp, &ruip->rui_item, lsn);
xfs_rui_release(ruip);
return 0;
}
const struct xlog_recover_item_ops xlog_rui_item_ops = {
.item_type = XFS_LI_RUI,
.commit_pass2 = xlog_recover_rui_commit_pass2,
};
/*
* This routine is called when an RUD format structure is found in a committed
* transaction in the log. Its purpose is to cancel the corresponding RUI if it
* was still in the log. To do this it searches the AIL for the RUI with an id
* equal to that in the RUD format structure. If we find it we drop the RUD
* reference, which removes the RUI from the AIL and frees it.
*/
STATIC int
xlog_recover_rud_commit_pass2(
struct xlog *log,
struct list_head *buffer_list,
struct xlog_recover_item *item,
xfs_lsn_t lsn)
{
struct xfs_rud_log_format *rud_formatp;
rud_formatp = item->ri_buf[0].i_addr;
if (item->ri_buf[0].i_len != sizeof(struct xfs_rud_log_format)) {
XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, log->l_mp,
rud_formatp, item->ri_buf[0].i_len);
return -EFSCORRUPTED;
}
xlog_recover_release_intent(log, XFS_LI_RUI, rud_formatp->rud_rui_id);
return 0;
}
const struct xlog_recover_item_ops xlog_rud_item_ops = {
.item_type = XFS_LI_RUD,
.commit_pass2 = xlog_recover_rud_commit_pass2,
};
| linux-master | fs/xfs/xfs_rmap_item.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_ioctl.h"
#include "xfs_trace.h"
#include "xfs_log.h"
#include "xfs_icache.h"
#include "xfs_pnfs.h"
#include "xfs_iomap.h"
#include "xfs_reflink.h"
#include <linux/dax.h>
#include <linux/falloc.h>
#include <linux/backing-dev.h>
#include <linux/mman.h>
#include <linux/fadvise.h>
#include <linux/mount.h>
static const struct vm_operations_struct xfs_file_vm_ops;
/*
* Decide if the given file range is aligned to the size of the fundamental
* allocation unit for the file.
*/
static bool
xfs_is_falloc_aligned(
struct xfs_inode *ip,
loff_t pos,
long long int len)
{
struct xfs_mount *mp = ip->i_mount;
uint64_t mask;
if (XFS_IS_REALTIME_INODE(ip)) {
if (!is_power_of_2(mp->m_sb.sb_rextsize)) {
u64 rextbytes;
u32 mod;
rextbytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
div_u64_rem(pos, rextbytes, &mod);
if (mod)
return false;
div_u64_rem(len, rextbytes, &mod);
return mod == 0;
}
mask = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize) - 1;
} else {
mask = mp->m_sb.sb_blocksize - 1;
}
return !((pos | len) & mask);
}
/*
* Fsync operations on directories are much simpler than on regular files,
* as there is no file data to flush, and thus also no need for explicit
* cache flush operations, and there are no non-transaction metadata updates
* on directories either.
*/
STATIC int
xfs_dir_fsync(
struct file *file,
loff_t start,
loff_t end,
int datasync)
{
struct xfs_inode *ip = XFS_I(file->f_mapping->host);
trace_xfs_dir_fsync(ip);
return xfs_log_force_inode(ip);
}
static xfs_csn_t
xfs_fsync_seq(
struct xfs_inode *ip,
bool datasync)
{
if (!xfs_ipincount(ip))
return 0;
if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
return 0;
return ip->i_itemp->ili_commit_seq;
}
/*
* All metadata updates are logged, which means that we just have to flush the
* log up to the latest LSN that touched the inode.
*
* If we have concurrent fsync/fdatasync() calls, we need them to all block on
* the log force before we clear the ili_fsync_fields field. This ensures that
* we don't get a racing sync operation that does not wait for the metadata to
* hit the journal before returning. If we race with clearing ili_fsync_fields,
* then all that will happen is the log force will do nothing as the lsn will
* already be on disk. We can't race with setting ili_fsync_fields because that
* is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock
* shared until after the ili_fsync_fields is cleared.
*/
static int
xfs_fsync_flush_log(
struct xfs_inode *ip,
bool datasync,
int *log_flushed)
{
int error = 0;
xfs_csn_t seq;
xfs_ilock(ip, XFS_ILOCK_SHARED);
seq = xfs_fsync_seq(ip, datasync);
if (seq) {
error = xfs_log_force_seq(ip->i_mount, seq, XFS_LOG_SYNC,
log_flushed);
spin_lock(&ip->i_itemp->ili_lock);
ip->i_itemp->ili_fsync_fields = 0;
spin_unlock(&ip->i_itemp->ili_lock);
}
xfs_iunlock(ip, XFS_ILOCK_SHARED);
return error;
}
STATIC int
xfs_file_fsync(
struct file *file,
loff_t start,
loff_t end,
int datasync)
{
struct xfs_inode *ip = XFS_I(file->f_mapping->host);
struct xfs_mount *mp = ip->i_mount;
int error, err2;
int log_flushed = 0;
trace_xfs_file_fsync(ip);
error = file_write_and_wait_range(file, start, end);
if (error)
return error;
if (xfs_is_shutdown(mp))
return -EIO;
xfs_iflags_clear(ip, XFS_ITRUNCATED);
/*
* If we have an RT and/or log subvolume we need to make sure to flush
* the write cache the device used for file data first. This is to
* ensure newly written file data make it to disk before logging the new
* inode size in case of an extending write.
*/
if (XFS_IS_REALTIME_INODE(ip))
error = blkdev_issue_flush(mp->m_rtdev_targp->bt_bdev);
else if (mp->m_logdev_targp != mp->m_ddev_targp)
error = blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
/*
* Any inode that has dirty modifications in the log is pinned. The
* racy check here for a pinned inode will not catch modifications
* that happen concurrently to the fsync call, but fsync semantics
* only require to sync previously completed I/O.
*/
if (xfs_ipincount(ip)) {
err2 = xfs_fsync_flush_log(ip, datasync, &log_flushed);
if (err2 && !error)
error = err2;
}
/*
* If we only have a single device, and the log force about was
* a no-op we might have to flush the data device cache here.
* This can only happen for fdatasync/O_DSYNC if we were overwriting
* an already allocated file and thus do not have any metadata to
* commit.
*/
if (!log_flushed && !XFS_IS_REALTIME_INODE(ip) &&
mp->m_logdev_targp == mp->m_ddev_targp) {
err2 = blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
if (err2 && !error)
error = err2;
}
return error;
}
static int
xfs_ilock_iocb(
struct kiocb *iocb,
unsigned int lock_mode)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!xfs_ilock_nowait(ip, lock_mode))
return -EAGAIN;
} else {
xfs_ilock(ip, lock_mode);
}
return 0;
}
STATIC ssize_t
xfs_file_dio_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
ssize_t ret;
trace_xfs_file_direct_read(iocb, to);
if (!iov_iter_count(to))
return 0; /* skip atime */
file_accessed(iocb->ki_filp);
ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
if (ret)
return ret;
ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL, 0, NULL, 0);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
static noinline ssize_t
xfs_file_dax_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_inode *ip = XFS_I(iocb->ki_filp->f_mapping->host);
ssize_t ret = 0;
trace_xfs_file_dax_read(iocb, to);
if (!iov_iter_count(to))
return 0; /* skip atime */
ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
if (ret)
return ret;
ret = dax_iomap_rw(iocb, to, &xfs_read_iomap_ops);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
file_accessed(iocb->ki_filp);
return ret;
}
STATIC ssize_t
xfs_file_buffered_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
ssize_t ret;
trace_xfs_file_buffered_read(iocb, to);
ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
if (ret)
return ret;
ret = generic_file_read_iter(iocb, to);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
STATIC ssize_t
xfs_file_read_iter(
struct kiocb *iocb,
struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct xfs_mount *mp = XFS_I(inode)->i_mount;
ssize_t ret = 0;
XFS_STATS_INC(mp, xs_read_calls);
if (xfs_is_shutdown(mp))
return -EIO;
if (IS_DAX(inode))
ret = xfs_file_dax_read(iocb, to);
else if (iocb->ki_flags & IOCB_DIRECT)
ret = xfs_file_dio_read(iocb, to);
else
ret = xfs_file_buffered_read(iocb, to);
if (ret > 0)
XFS_STATS_ADD(mp, xs_read_bytes, ret);
return ret;
}
STATIC ssize_t
xfs_file_splice_read(
struct file *in,
loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len,
unsigned int flags)
{
struct inode *inode = file_inode(in);
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
ssize_t ret = 0;
XFS_STATS_INC(mp, xs_read_calls);
if (xfs_is_shutdown(mp))
return -EIO;
trace_xfs_file_splice_read(ip, *ppos, len);
xfs_ilock(ip, XFS_IOLOCK_SHARED);
ret = filemap_splice_read(in, ppos, pipe, len, flags);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
if (ret > 0)
XFS_STATS_ADD(mp, xs_read_bytes, ret);
return ret;
}
/*
* Common pre-write limit and setup checks.
*
* Called with the iolocked held either shared and exclusive according to
* @iolock, and returns with it held. Might upgrade the iolock to exclusive
* if called for a direct write beyond i_size.
*/
STATIC ssize_t
xfs_file_write_checks(
struct kiocb *iocb,
struct iov_iter *from,
unsigned int *iolock)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t error = 0;
size_t count = iov_iter_count(from);
bool drained_dio = false;
loff_t isize;
restart:
error = generic_write_checks(iocb, from);
if (error <= 0)
return error;
if (iocb->ki_flags & IOCB_NOWAIT) {
error = break_layout(inode, false);
if (error == -EWOULDBLOCK)
error = -EAGAIN;
} else {
error = xfs_break_layouts(inode, iolock, BREAK_WRITE);
}
if (error)
return error;
/*
* For changing security info in file_remove_privs() we need i_rwsem
* exclusively.
*/
if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {
xfs_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
error = xfs_ilock_iocb(iocb, *iolock);
if (error) {
*iolock = 0;
return error;
}
goto restart;
}
/*
* If the offset is beyond the size of the file, we need to zero any
* blocks that fall between the existing EOF and the start of this
* write. If zeroing is needed and we are currently holding the iolock
* shared, we need to update it to exclusive which implies having to
* redo all checks before.
*
* We need to serialise against EOF updates that occur in IO completions
* here. We want to make sure that nobody is changing the size while we
* do this check until we have placed an IO barrier (i.e. hold the
* XFS_IOLOCK_EXCL) that prevents new IO from being dispatched. The
* spinlock effectively forms a memory barrier once we have the
* XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value and
* hence be able to correctly determine if we need to run zeroing.
*
* We can do an unlocked check here safely as IO completion can only
* extend EOF. Truncate is locked out at this point, so the EOF can
* not move backwards, only forwards. Hence we only need to take the
* slow path and spin locks when we are at or beyond the current EOF.
*/
if (iocb->ki_pos <= i_size_read(inode))
goto out;
spin_lock(&ip->i_flags_lock);
isize = i_size_read(inode);
if (iocb->ki_pos > isize) {
spin_unlock(&ip->i_flags_lock);
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
if (!drained_dio) {
if (*iolock == XFS_IOLOCK_SHARED) {
xfs_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
xfs_ilock(ip, *iolock);
iov_iter_reexpand(from, count);
}
/*
* We now have an IO submission barrier in place, but
* AIO can do EOF updates during IO completion and hence
* we now need to wait for all of them to drain. Non-AIO
* DIO will have drained before we are given the
* XFS_IOLOCK_EXCL, and so for most cases this wait is a
* no-op.
*/
inode_dio_wait(inode);
drained_dio = true;
goto restart;
}
trace_xfs_zero_eof(ip, isize, iocb->ki_pos - isize);
error = xfs_zero_range(ip, isize, iocb->ki_pos - isize, NULL);
if (error)
return error;
} else
spin_unlock(&ip->i_flags_lock);
out:
return kiocb_modified(iocb);
}
static int
xfs_dio_write_end_io(
struct kiocb *iocb,
ssize_t size,
int error,
unsigned flags)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct xfs_inode *ip = XFS_I(inode);
loff_t offset = iocb->ki_pos;
unsigned int nofs_flag;
trace_xfs_end_io_direct_write(ip, offset, size);
if (xfs_is_shutdown(ip->i_mount))
return -EIO;
if (error)
return error;
if (!size)
return 0;
/*
* Capture amount written on completion as we can't reliably account
* for it on submission.
*/
XFS_STATS_ADD(ip->i_mount, xs_write_bytes, size);
/*
* We can allocate memory here while doing writeback on behalf of
* memory reclaim. To avoid memory allocation deadlocks set the
* task-wide nofs context for the following operations.
*/
nofs_flag = memalloc_nofs_save();
if (flags & IOMAP_DIO_COW) {
error = xfs_reflink_end_cow(ip, offset, size);
if (error)
goto out;
}
/*
* Unwritten conversion updates the in-core isize after extent
* conversion but before updating the on-disk size. Updating isize any
* earlier allows a racing dio read to find unwritten extents before
* they are converted.
*/
if (flags & IOMAP_DIO_UNWRITTEN) {
error = xfs_iomap_write_unwritten(ip, offset, size, true);
goto out;
}
/*
* We need to update the in-core inode size here so that we don't end up
* with the on-disk inode size being outside the in-core inode size. We
* have no other method of updating EOF for AIO, so always do it here
* if necessary.
*
* We need to lock the test/set EOF update as we can be racing with
* other IO completions here to update the EOF. Failing to serialise
* here can result in EOF moving backwards and Bad Things Happen when
* that occurs.
*
* As IO completion only ever extends EOF, we can do an unlocked check
* here to avoid taking the spinlock. If we land within the current EOF,
* then we do not need to do an extending update at all, and we don't
* need to take the lock to check this. If we race with an update moving
* EOF, then we'll either still be beyond EOF and need to take the lock,
* or we'll be within EOF and we don't need to take it at all.
*/
if (offset + size <= i_size_read(inode))
goto out;
spin_lock(&ip->i_flags_lock);
if (offset + size > i_size_read(inode)) {
i_size_write(inode, offset + size);
spin_unlock(&ip->i_flags_lock);
error = xfs_setfilesize(ip, offset, size);
} else {
spin_unlock(&ip->i_flags_lock);
}
out:
memalloc_nofs_restore(nofs_flag);
return error;
}
static const struct iomap_dio_ops xfs_dio_write_ops = {
.end_io = xfs_dio_write_end_io,
};
/*
* Handle block aligned direct I/O writes
*/
static noinline ssize_t
xfs_file_dio_write_aligned(
struct xfs_inode *ip,
struct kiocb *iocb,
struct iov_iter *from)
{
unsigned int iolock = XFS_IOLOCK_SHARED;
ssize_t ret;
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out_unlock;
/*
* We don't need to hold the IOLOCK exclusively across the IO, so demote
* the iolock back to shared if we had to take the exclusive lock in
* xfs_file_write_checks() for other reasons.
*/
if (iolock == XFS_IOLOCK_EXCL) {
xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
iolock = XFS_IOLOCK_SHARED;
}
trace_xfs_file_direct_write(iocb, from);
ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
&xfs_dio_write_ops, 0, NULL, 0);
out_unlock:
if (iolock)
xfs_iunlock(ip, iolock);
return ret;
}
/*
* Handle block unaligned direct I/O writes
*
* In most cases direct I/O writes will be done holding IOLOCK_SHARED, allowing
* them to be done in parallel with reads and other direct I/O writes. However,
* if the I/O is not aligned to filesystem blocks, the direct I/O layer may need
* to do sub-block zeroing and that requires serialisation against other direct
* I/O to the same block. In this case we need to serialise the submission of
* the unaligned I/O so that we don't get racing block zeroing in the dio layer.
* In the case where sub-block zeroing is not required, we can do concurrent
* sub-block dios to the same block successfully.
*
* Optimistically submit the I/O using the shared lock first, but use the
* IOMAP_DIO_OVERWRITE_ONLY flag to tell the lower layers to return -EAGAIN
* if block allocation or partial block zeroing would be required. In that case
* we try again with the exclusive lock.
*/
static noinline ssize_t
xfs_file_dio_write_unaligned(
struct xfs_inode *ip,
struct kiocb *iocb,
struct iov_iter *from)
{
size_t isize = i_size_read(VFS_I(ip));
size_t count = iov_iter_count(from);
unsigned int iolock = XFS_IOLOCK_SHARED;
unsigned int flags = IOMAP_DIO_OVERWRITE_ONLY;
ssize_t ret;
/*
* Extending writes need exclusivity because of the sub-block zeroing
* that the DIO code always does for partial tail blocks beyond EOF, so
* don't even bother trying the fast path in this case.
*/
if (iocb->ki_pos > isize || iocb->ki_pos + count >= isize) {
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
retry_exclusive:
iolock = XFS_IOLOCK_EXCL;
flags = IOMAP_DIO_FORCE_WAIT;
}
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
/*
* We can't properly handle unaligned direct I/O to reflink files yet,
* as we can't unshare a partial block.
*/
if (xfs_is_cow_inode(ip)) {
trace_xfs_reflink_bounce_dio_write(iocb, from);
ret = -ENOTBLK;
goto out_unlock;
}
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out_unlock;
/*
* If we are doing exclusive unaligned I/O, this must be the only I/O
* in-flight. Otherwise we risk data corruption due to unwritten extent
* conversions from the AIO end_io handler. Wait for all other I/O to
* drain first.
*/
if (flags & IOMAP_DIO_FORCE_WAIT)
inode_dio_wait(VFS_I(ip));
trace_xfs_file_direct_write(iocb, from);
ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
&xfs_dio_write_ops, flags, NULL, 0);
/*
* Retry unaligned I/O with exclusive blocking semantics if the DIO
* layer rejected it for mapping or locking reasons. If we are doing
* nonblocking user I/O, propagate the error.
*/
if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) {
ASSERT(flags & IOMAP_DIO_OVERWRITE_ONLY);
xfs_iunlock(ip, iolock);
goto retry_exclusive;
}
out_unlock:
if (iolock)
xfs_iunlock(ip, iolock);
return ret;
}
static ssize_t
xfs_file_dio_write(
struct kiocb *iocb,
struct iov_iter *from)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
size_t count = iov_iter_count(from);
/* direct I/O must be aligned to device logical sector size */
if ((iocb->ki_pos | count) & target->bt_logical_sectormask)
return -EINVAL;
if ((iocb->ki_pos | count) & ip->i_mount->m_blockmask)
return xfs_file_dio_write_unaligned(ip, iocb, from);
return xfs_file_dio_write_aligned(ip, iocb, from);
}
static noinline ssize_t
xfs_file_dax_write(
struct kiocb *iocb,
struct iov_iter *from)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct xfs_inode *ip = XFS_I(inode);
unsigned int iolock = XFS_IOLOCK_EXCL;
ssize_t ret, error = 0;
loff_t pos;
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out;
pos = iocb->ki_pos;
trace_xfs_file_dax_write(iocb, from);
ret = dax_iomap_rw(iocb, from, &xfs_dax_write_iomap_ops);
if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
i_size_write(inode, iocb->ki_pos);
error = xfs_setfilesize(ip, pos, ret);
}
out:
if (iolock)
xfs_iunlock(ip, iolock);
if (error)
return error;
if (ret > 0) {
XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
/* Handle various SYNC-type writes */
ret = generic_write_sync(iocb, ret);
}
return ret;
}
STATIC ssize_t
xfs_file_buffered_write(
struct kiocb *iocb,
struct iov_iter *from)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
bool cleared_space = false;
unsigned int iolock;
write_retry:
iolock = XFS_IOLOCK_EXCL;
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out;
trace_xfs_file_buffered_write(iocb, from);
ret = iomap_file_buffered_write(iocb, from,
&xfs_buffered_write_iomap_ops);
/*
* If we hit a space limit, try to free up some lingering preallocated
* space before returning an error. In the case of ENOSPC, first try to
* write back all dirty inodes to free up some of the excess reserved
* metadata space. This reduces the chances that the eofblocks scan
* waits on dirty mappings. Since xfs_flush_inodes() is serialized, this
* also behaves as a filter to prevent too many eofblocks scans from
* running at the same time. Use a synchronous scan to increase the
* effectiveness of the scan.
*/
if (ret == -EDQUOT && !cleared_space) {
xfs_iunlock(ip, iolock);
xfs_blockgc_free_quota(ip, XFS_ICWALK_FLAG_SYNC);
cleared_space = true;
goto write_retry;
} else if (ret == -ENOSPC && !cleared_space) {
struct xfs_icwalk icw = {0};
cleared_space = true;
xfs_flush_inodes(ip->i_mount);
xfs_iunlock(ip, iolock);
icw.icw_flags = XFS_ICWALK_FLAG_SYNC;
xfs_blockgc_free_space(ip->i_mount, &icw);
goto write_retry;
}
out:
if (iolock)
xfs_iunlock(ip, iolock);
if (ret > 0) {
XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
/* Handle various SYNC-type writes */
ret = generic_write_sync(iocb, ret);
}
return ret;
}
STATIC ssize_t
xfs_file_write_iter(
struct kiocb *iocb,
struct iov_iter *from)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
size_t ocount = iov_iter_count(from);
XFS_STATS_INC(ip->i_mount, xs_write_calls);
if (ocount == 0)
return 0;
if (xfs_is_shutdown(ip->i_mount))
return -EIO;
if (IS_DAX(inode))
return xfs_file_dax_write(iocb, from);
if (iocb->ki_flags & IOCB_DIRECT) {
/*
* Allow a directio write to fall back to a buffered
* write *only* in the case that we're doing a reflink
* CoW. In all other directio scenarios we do not
* allow an operation to fall back to buffered mode.
*/
ret = xfs_file_dio_write(iocb, from);
if (ret != -ENOTBLK)
return ret;
}
return xfs_file_buffered_write(iocb, from);
}
static void
xfs_wait_dax_page(
struct inode *inode)
{
struct xfs_inode *ip = XFS_I(inode);
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
schedule();
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
}
int
xfs_break_dax_layouts(
struct inode *inode,
bool *retry)
{
struct page *page;
ASSERT(xfs_isilocked(XFS_I(inode), XFS_MMAPLOCK_EXCL));
page = dax_layout_busy_page(inode->i_mapping);
if (!page)
return 0;
*retry = true;
return ___wait_var_event(&page->_refcount,
atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
0, 0, xfs_wait_dax_page(inode));
}
int
xfs_break_layouts(
struct inode *inode,
uint *iolock,
enum layout_break_reason reason)
{
bool retry;
int error;
ASSERT(xfs_isilocked(XFS_I(inode), XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
do {
retry = false;
switch (reason) {
case BREAK_UNMAP:
error = xfs_break_dax_layouts(inode, &retry);
if (error || retry)
break;
fallthrough;
case BREAK_WRITE:
error = xfs_break_leased_layouts(inode, iolock, &retry);
break;
default:
WARN_ON_ONCE(1);
error = -EINVAL;
}
} while (error == 0 && retry);
return error;
}
/* Does this file, inode, or mount want synchronous writes? */
static inline bool xfs_file_sync_writes(struct file *filp)
{
struct xfs_inode *ip = XFS_I(file_inode(filp));
if (xfs_has_wsync(ip->i_mount))
return true;
if (filp->f_flags & (__O_SYNC | O_DSYNC))
return true;
if (IS_SYNC(file_inode(filp)))
return true;
return false;
}
#define XFS_FALLOC_FL_SUPPORTED \
(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \
FALLOC_FL_INSERT_RANGE | FALLOC_FL_UNSHARE_RANGE)
STATIC long
xfs_file_fallocate(
struct file *file,
int mode,
loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
struct xfs_inode *ip = XFS_I(inode);
long error;
uint iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
loff_t new_size = 0;
bool do_file_insert = false;
if (!S_ISREG(inode->i_mode))
return -EINVAL;
if (mode & ~XFS_FALLOC_FL_SUPPORTED)
return -EOPNOTSUPP;
xfs_ilock(ip, iolock);
error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
if (error)
goto out_unlock;
/*
* Must wait for all AIO to complete before we continue as AIO can
* change the file size on completion without holding any locks we
* currently hold. We must do this first because AIO can update both
* the on disk and in memory inode sizes, and the operations that follow
* require the in-memory size to be fully up-to-date.
*/
inode_dio_wait(inode);
/*
* Now AIO and DIO has drained we flush and (if necessary) invalidate
* the cached range over the first operation we are about to run.
*
* We care about zero and collapse here because they both run a hole
* punch over the range first. Because that can zero data, and the range
* of invalidation for the shift operations is much larger, we still do
* the required flush for collapse in xfs_prepare_shift().
*
* Insert has the same range requirements as collapse, and we extend the
* file first which can zero data. Hence insert has the same
* flush/invalidate requirements as collapse and so they are both
* handled at the right time by xfs_prepare_shift().
*/
if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE |
FALLOC_FL_COLLAPSE_RANGE)) {
error = xfs_flush_unmap_range(ip, offset, len);
if (error)
goto out_unlock;
}
error = file_modified(file);
if (error)
goto out_unlock;
if (mode & FALLOC_FL_PUNCH_HOLE) {
error = xfs_free_file_space(ip, offset, len);
if (error)
goto out_unlock;
} else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
if (!xfs_is_falloc_aligned(ip, offset, len)) {
error = -EINVAL;
goto out_unlock;
}
/*
* There is no need to overlap collapse range with EOF,
* in which case it is effectively a truncate operation
*/
if (offset + len >= i_size_read(inode)) {
error = -EINVAL;
goto out_unlock;
}
new_size = i_size_read(inode) - len;
error = xfs_collapse_file_space(ip, offset, len);
if (error)
goto out_unlock;
} else if (mode & FALLOC_FL_INSERT_RANGE) {
loff_t isize = i_size_read(inode);
if (!xfs_is_falloc_aligned(ip, offset, len)) {
error = -EINVAL;
goto out_unlock;
}
/*
* New inode size must not exceed ->s_maxbytes, accounting for
* possible signed overflow.
*/
if (inode->i_sb->s_maxbytes - isize < len) {
error = -EFBIG;
goto out_unlock;
}
new_size = isize + len;
/* Offset should be less than i_size */
if (offset >= isize) {
error = -EINVAL;
goto out_unlock;
}
do_file_insert = true;
} else {
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
offset + len > i_size_read(inode)) {
new_size = offset + len;
error = inode_newsize_ok(inode, new_size);
if (error)
goto out_unlock;
}
if (mode & FALLOC_FL_ZERO_RANGE) {
/*
* Punch a hole and prealloc the range. We use a hole
* punch rather than unwritten extent conversion for two
* reasons:
*
* 1.) Hole punch handles partial block zeroing for us.
* 2.) If prealloc returns ENOSPC, the file range is
* still zero-valued by virtue of the hole punch.
*/
unsigned int blksize = i_blocksize(inode);
trace_xfs_zero_file_space(ip);
error = xfs_free_file_space(ip, offset, len);
if (error)
goto out_unlock;
len = round_up(offset + len, blksize) -
round_down(offset, blksize);
offset = round_down(offset, blksize);
} else if (mode & FALLOC_FL_UNSHARE_RANGE) {
error = xfs_reflink_unshare(ip, offset, len);
if (error)
goto out_unlock;
} else {
/*
* If always_cow mode we can't use preallocations and
* thus should not create them.
*/
if (xfs_is_always_cow_inode(ip)) {
error = -EOPNOTSUPP;
goto out_unlock;
}
}
if (!xfs_is_always_cow_inode(ip)) {
error = xfs_alloc_file_space(ip, offset, len);
if (error)
goto out_unlock;
}
}
/* Change file size if needed */
if (new_size) {
struct iattr iattr;
iattr.ia_valid = ATTR_SIZE;
iattr.ia_size = new_size;
error = xfs_vn_setattr_size(file_mnt_idmap(file),
file_dentry(file), &iattr);
if (error)
goto out_unlock;
}
/*
* Perform hole insertion now that the file size has been
* updated so that if we crash during the operation we don't
* leave shifted extents past EOF and hence losing access to
* the data that is contained within them.
*/
if (do_file_insert) {
error = xfs_insert_file_space(ip, offset, len);
if (error)
goto out_unlock;
}
if (xfs_file_sync_writes(file))
error = xfs_log_force_inode(ip);
out_unlock:
xfs_iunlock(ip, iolock);
return error;
}
STATIC int
xfs_file_fadvise(
struct file *file,
loff_t start,
loff_t end,
int advice)
{
struct xfs_inode *ip = XFS_I(file_inode(file));
int ret;
int lockflags = 0;
/*
* Operations creating pages in page cache need protection from hole
* punching and similar ops
*/
if (advice == POSIX_FADV_WILLNEED) {
lockflags = XFS_IOLOCK_SHARED;
xfs_ilock(ip, lockflags);
}
ret = generic_fadvise(file, start, end, advice);
if (lockflags)
xfs_iunlock(ip, lockflags);
return ret;
}
STATIC loff_t
xfs_file_remap_range(
struct file *file_in,
loff_t pos_in,
struct file *file_out,
loff_t pos_out,
loff_t len,
unsigned int remap_flags)
{
struct inode *inode_in = file_inode(file_in);
struct xfs_inode *src = XFS_I(inode_in);
struct inode *inode_out = file_inode(file_out);
struct xfs_inode *dest = XFS_I(inode_out);
struct xfs_mount *mp = src->i_mount;
loff_t remapped = 0;
xfs_extlen_t cowextsize;
int ret;
if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
return -EINVAL;
if (!xfs_has_reflink(mp))
return -EOPNOTSUPP;
if (xfs_is_shutdown(mp))
return -EIO;
/* Prepare and then clone file data. */
ret = xfs_reflink_remap_prep(file_in, pos_in, file_out, pos_out,
&len, remap_flags);
if (ret || len == 0)
return ret;
trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
ret = xfs_reflink_remap_blocks(src, pos_in, dest, pos_out, len,
&remapped);
if (ret)
goto out_unlock;
/*
* Carry the cowextsize hint from src to dest if we're sharing the
* entire source file to the entire destination file, the source file
* has a cowextsize hint, and the destination file does not.
*/
cowextsize = 0;
if (pos_in == 0 && len == i_size_read(inode_in) &&
(src->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) &&
pos_out == 0 && len >= i_size_read(inode_out) &&
!(dest->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE))
cowextsize = src->i_cowextsize;
ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
remap_flags);
if (ret)
goto out_unlock;
if (xfs_file_sync_writes(file_in) || xfs_file_sync_writes(file_out))
xfs_log_force_inode(dest);
out_unlock:
xfs_iunlock2_io_mmap(src, dest);
if (ret)
trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);
return remapped > 0 ? remapped : ret;
}
STATIC int
xfs_file_open(
struct inode *inode,
struct file *file)
{
if (xfs_is_shutdown(XFS_M(inode->i_sb)))
return -EIO;
file->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC |
FMODE_DIO_PARALLEL_WRITE | FMODE_CAN_ODIRECT;
return generic_file_open(inode, file);
}
STATIC int
xfs_dir_open(
struct inode *inode,
struct file *file)
{
struct xfs_inode *ip = XFS_I(inode);
unsigned int mode;
int error;
error = xfs_file_open(inode, file);
if (error)
return error;
/*
* If there are any blocks, read-ahead block 0 as we're almost
* certain to have the next operation be a read there.
*/
mode = xfs_ilock_data_map_shared(ip);
if (ip->i_df.if_nextents > 0)
error = xfs_dir3_data_readahead(ip, 0, 0);
xfs_iunlock(ip, mode);
return error;
}
STATIC int
xfs_file_release(
struct inode *inode,
struct file *filp)
{
return xfs_release(XFS_I(inode));
}
STATIC int
xfs_file_readdir(
struct file *file,
struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
xfs_inode_t *ip = XFS_I(inode);
size_t bufsize;
/*
* The Linux API doesn't pass down the total size of the buffer
* we read into down to the filesystem. With the filldir concept
* it's not needed for correct information, but the XFS dir2 leaf
* code wants an estimate of the buffer size to calculate it's
* readahead window and size the buffers used for mapping to
* physical blocks.
*
* Try to give it an estimate that's good enough, maybe at some
* point we can change the ->readdir prototype to include the
* buffer size. For now we use the current glibc buffer size.
*/
bufsize = (size_t)min_t(loff_t, XFS_READDIR_BUFSIZE, ip->i_disk_size);
return xfs_readdir(NULL, ip, ctx, bufsize);
}
STATIC loff_t
xfs_file_llseek(
struct file *file,
loff_t offset,
int whence)
{
struct inode *inode = file->f_mapping->host;
if (xfs_is_shutdown(XFS_I(inode)->i_mount))
return -EIO;
switch (whence) {
default:
return generic_file_llseek(file, offset, whence);
case SEEK_HOLE:
offset = iomap_seek_hole(inode, offset, &xfs_seek_iomap_ops);
break;
case SEEK_DATA:
offset = iomap_seek_data(inode, offset, &xfs_seek_iomap_ops);
break;
}
if (offset < 0)
return offset;
return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
}
#ifdef CONFIG_FS_DAX
static inline vm_fault_t
xfs_dax_fault(
struct vm_fault *vmf,
unsigned int order,
bool write_fault,
pfn_t *pfn)
{
return dax_iomap_fault(vmf, order, pfn, NULL,
(write_fault && !vmf->cow_page) ?
&xfs_dax_write_iomap_ops :
&xfs_read_iomap_ops);
}
#else
static inline vm_fault_t
xfs_dax_fault(
struct vm_fault *vmf,
unsigned int order,
bool write_fault,
pfn_t *pfn)
{
ASSERT(0);
return VM_FAULT_SIGBUS;
}
#endif
/*
* Locking for serialisation of IO during page faults. This results in a lock
* ordering of:
*
* mmap_lock (MM)
* sb_start_pagefault(vfs, freeze)
* invalidate_lock (vfs/XFS_MMAPLOCK - truncate serialisation)
* page_lock (MM)
* i_lock (XFS - extent map serialisation)
*/
static vm_fault_t
__xfs_filemap_fault(
struct vm_fault *vmf,
unsigned int order,
bool write_fault)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
struct xfs_inode *ip = XFS_I(inode);
vm_fault_t ret;
trace_xfs_filemap_fault(ip, order, write_fault);
if (write_fault) {
sb_start_pagefault(inode->i_sb);
file_update_time(vmf->vma->vm_file);
}
if (IS_DAX(inode)) {
pfn_t pfn;
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
ret = xfs_dax_fault(vmf, order, write_fault, &pfn);
if (ret & VM_FAULT_NEEDDSYNC)
ret = dax_finish_sync_fault(vmf, order, pfn);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
} else {
if (write_fault) {
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
ret = iomap_page_mkwrite(vmf,
&xfs_page_mkwrite_iomap_ops);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
} else {
ret = filemap_fault(vmf);
}
}
if (write_fault)
sb_end_pagefault(inode->i_sb);
return ret;
}
static inline bool
xfs_is_write_fault(
struct vm_fault *vmf)
{
return (vmf->flags & FAULT_FLAG_WRITE) &&
(vmf->vma->vm_flags & VM_SHARED);
}
static vm_fault_t
xfs_filemap_fault(
struct vm_fault *vmf)
{
/* DAX can shortcut the normal fault path on write faults! */
return __xfs_filemap_fault(vmf, 0,
IS_DAX(file_inode(vmf->vma->vm_file)) &&
xfs_is_write_fault(vmf));
}
static vm_fault_t
xfs_filemap_huge_fault(
struct vm_fault *vmf,
unsigned int order)
{
if (!IS_DAX(file_inode(vmf->vma->vm_file)))
return VM_FAULT_FALLBACK;
/* DAX can shortcut the normal fault path on write faults! */
return __xfs_filemap_fault(vmf, order,
xfs_is_write_fault(vmf));
}
static vm_fault_t
xfs_filemap_page_mkwrite(
struct vm_fault *vmf)
{
return __xfs_filemap_fault(vmf, 0, true);
}
/*
* pfn_mkwrite was originally intended to ensure we capture time stamp updates
* on write faults. In reality, it needs to serialise against truncate and
* prepare memory for writing so handle is as standard write fault.
*/
static vm_fault_t
xfs_filemap_pfn_mkwrite(
struct vm_fault *vmf)
{
return __xfs_filemap_fault(vmf, 0, true);
}
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = xfs_filemap_fault,
.huge_fault = xfs_filemap_huge_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = xfs_filemap_page_mkwrite,
.pfn_mkwrite = xfs_filemap_pfn_mkwrite,
};
STATIC int
xfs_file_mmap(
struct file *file,
struct vm_area_struct *vma)
{
struct inode *inode = file_inode(file);
struct xfs_buftarg *target = xfs_inode_buftarg(XFS_I(inode));
/*
* We don't support synchronous mappings for non-DAX files and
* for DAX files if underneath dax_device is not synchronous.
*/
if (!daxdev_mapping_supported(vma, target->bt_daxdev))
return -EOPNOTSUPP;
file_accessed(file);
vma->vm_ops = &xfs_file_vm_ops;
if (IS_DAX(inode))
vm_flags_set(vma, VM_HUGEPAGE);
return 0;
}
const struct file_operations xfs_file_operations = {
.llseek = xfs_file_llseek,
.read_iter = xfs_file_read_iter,
.write_iter = xfs_file_write_iter,
.splice_read = xfs_file_splice_read,
.splice_write = iter_file_splice_write,
.iopoll = iocb_bio_iopoll,
.unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = xfs_file_compat_ioctl,
#endif
.mmap = xfs_file_mmap,
.mmap_supported_flags = MAP_SYNC,
.open = xfs_file_open,
.release = xfs_file_release,
.fsync = xfs_file_fsync,
.get_unmapped_area = thp_get_unmapped_area,
.fallocate = xfs_file_fallocate,
.fadvise = xfs_file_fadvise,
.remap_file_range = xfs_file_remap_range,
};
const struct file_operations xfs_dir_file_operations = {
.open = xfs_dir_open,
.read = generic_read_dir,
.iterate_shared = xfs_file_readdir,
.llseek = generic_file_llseek,
.unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = xfs_file_compat_ioctl,
#endif
.fsync = xfs_dir_fsync,
};
| linux-master | fs/xfs/xfs_file.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2019 Christoph Hellwig.
*/
#include "xfs.h"
static inline unsigned int bio_max_vecs(unsigned int count)
{
return bio_max_segs(howmany(count, PAGE_SIZE));
}
int
xfs_rw_bdev(
struct block_device *bdev,
sector_t sector,
unsigned int count,
char *data,
enum req_op op)
{
unsigned int is_vmalloc = is_vmalloc_addr(data);
unsigned int left = count;
int error;
struct bio *bio;
if (is_vmalloc && op == REQ_OP_WRITE)
flush_kernel_vmap_range(data, count);
bio = bio_alloc(bdev, bio_max_vecs(left), op | REQ_META | REQ_SYNC,
GFP_KERNEL);
bio->bi_iter.bi_sector = sector;
do {
struct page *page = kmem_to_page(data);
unsigned int off = offset_in_page(data);
unsigned int len = min_t(unsigned, left, PAGE_SIZE - off);
while (bio_add_page(bio, page, len, off) != len) {
struct bio *prev = bio;
bio = bio_alloc(prev->bi_bdev, bio_max_vecs(left),
prev->bi_opf, GFP_KERNEL);
bio->bi_iter.bi_sector = bio_end_sector(prev);
bio_chain(prev, bio);
submit_bio(prev);
}
data += len;
left -= len;
} while (left > 0);
error = submit_bio_wait(bio);
bio_put(bio);
if (is_vmalloc && op == REQ_OP_READ)
invalidate_kernel_vmap_range(data, count);
return error;
}
| linux-master | fs/xfs/xfs_bio_io.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* Copyright (c) 2012 Red Hat, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_trans.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_bmap_btree.h"
#include "xfs_rtalloc.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_trans_space.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_iomap.h"
#include "xfs_reflink.h"
/* Kernel only BMAP related definitions and functions */
/*
* Convert the given file system block to a disk block. We have to treat it
* differently based on whether the file is a real time file or not, because the
* bmap code does.
*/
xfs_daddr_t
xfs_fsb_to_db(struct xfs_inode *ip, xfs_fsblock_t fsb)
{
if (XFS_IS_REALTIME_INODE(ip))
return XFS_FSB_TO_BB(ip->i_mount, fsb);
return XFS_FSB_TO_DADDR(ip->i_mount, fsb);
}
/*
* Routine to zero an extent on disk allocated to the specific inode.
*
* The VFS functions take a linearised filesystem block offset, so we have to
* convert the sparse xfs fsb to the right format first.
* VFS types are real funky, too.
*/
int
xfs_zero_extent(
struct xfs_inode *ip,
xfs_fsblock_t start_fsb,
xfs_off_t count_fsb)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
xfs_daddr_t sector = xfs_fsb_to_db(ip, start_fsb);
sector_t block = XFS_BB_TO_FSBT(mp, sector);
return blkdev_issue_zeroout(target->bt_bdev,
block << (mp->m_super->s_blocksize_bits - 9),
count_fsb << (mp->m_super->s_blocksize_bits - 9),
GFP_NOFS, 0);
}
#ifdef CONFIG_XFS_RT
int
xfs_bmap_rtalloc(
struct xfs_bmalloca *ap)
{
struct xfs_mount *mp = ap->ip->i_mount;
xfs_fileoff_t orig_offset = ap->offset;
xfs_rtblock_t rtb;
xfs_extlen_t prod = 0; /* product factor for allocators */
xfs_extlen_t mod = 0; /* product factor for allocators */
xfs_extlen_t ralen = 0; /* realtime allocation length */
xfs_extlen_t align; /* minimum allocation alignment */
xfs_extlen_t orig_length = ap->length;
xfs_extlen_t minlen = mp->m_sb.sb_rextsize;
xfs_extlen_t raminlen;
bool rtlocked = false;
bool ignore_locality = false;
int error;
align = xfs_get_extsz_hint(ap->ip);
retry:
prod = align / mp->m_sb.sb_rextsize;
error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev,
align, 1, ap->eof, 0,
ap->conv, &ap->offset, &ap->length);
if (error)
return error;
ASSERT(ap->length);
ASSERT(ap->length % mp->m_sb.sb_rextsize == 0);
/*
* If we shifted the file offset downward to satisfy an extent size
* hint, increase minlen by that amount so that the allocator won't
* give us an allocation that's too short to cover at least one of the
* blocks that the caller asked for.
*/
if (ap->offset != orig_offset)
minlen += orig_offset - ap->offset;
/*
* If the offset & length are not perfectly aligned
* then kill prod, it will just get us in trouble.
*/
div_u64_rem(ap->offset, align, &mod);
if (mod || ap->length % align)
prod = 1;
/*
* Set ralen to be the actual requested length in rtextents.
*/
ralen = ap->length / mp->m_sb.sb_rextsize;
/*
* If the old value was close enough to XFS_BMBT_MAX_EXTLEN that
* we rounded up to it, cut it back so it's valid again.
* Note that if it's a really large request (bigger than
* XFS_BMBT_MAX_EXTLEN), we don't hear about that number, and can't
* adjust the starting point to match it.
*/
if (ralen * mp->m_sb.sb_rextsize >= XFS_MAX_BMBT_EXTLEN)
ralen = XFS_MAX_BMBT_EXTLEN / mp->m_sb.sb_rextsize;
/*
* Lock out modifications to both the RT bitmap and summary inodes
*/
if (!rtlocked) {
xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL|XFS_ILOCK_RTBITMAP);
xfs_trans_ijoin(ap->tp, mp->m_rbmip, XFS_ILOCK_EXCL);
xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL|XFS_ILOCK_RTSUM);
xfs_trans_ijoin(ap->tp, mp->m_rsumip, XFS_ILOCK_EXCL);
rtlocked = true;
}
/*
* If it's an allocation to an empty file at offset 0,
* pick an extent that will space things out in the rt area.
*/
if (ap->eof && ap->offset == 0) {
xfs_rtblock_t rtx; /* realtime extent no */
error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);
if (error)
return error;
ap->blkno = rtx * mp->m_sb.sb_rextsize;
} else {
ap->blkno = 0;
}
xfs_bmap_adjacent(ap);
/*
* Realtime allocation, done through xfs_rtallocate_extent.
*/
if (ignore_locality)
ap->blkno = 0;
else
do_div(ap->blkno, mp->m_sb.sb_rextsize);
rtb = ap->blkno;
ap->length = ralen;
raminlen = max_t(xfs_extlen_t, 1, minlen / mp->m_sb.sb_rextsize);
error = xfs_rtallocate_extent(ap->tp, ap->blkno, raminlen, ap->length,
&ralen, ap->wasdel, prod, &rtb);
if (error)
return error;
if (rtb != NULLRTBLOCK) {
ap->blkno = rtb * mp->m_sb.sb_rextsize;
ap->length = ralen * mp->m_sb.sb_rextsize;
ap->ip->i_nblocks += ap->length;
xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
if (ap->wasdel)
ap->ip->i_delayed_blks -= ap->length;
/*
* Adjust the disk quota also. This was reserved
* earlier.
*/
xfs_trans_mod_dquot_byino(ap->tp, ap->ip,
ap->wasdel ? XFS_TRANS_DQ_DELRTBCOUNT :
XFS_TRANS_DQ_RTBCOUNT, ap->length);
return 0;
}
if (align > mp->m_sb.sb_rextsize) {
/*
* We previously enlarged the request length to try to satisfy
* an extent size hint. The allocator didn't return anything,
* so reset the parameters to the original values and try again
* without alignment criteria.
*/
ap->offset = orig_offset;
ap->length = orig_length;
minlen = align = mp->m_sb.sb_rextsize;
goto retry;
}
if (!ignore_locality && ap->blkno != 0) {
/*
* If we can't allocate near a specific rt extent, try again
* without locality criteria.
*/
ignore_locality = true;
goto retry;
}
ap->blkno = NULLFSBLOCK;
ap->length = 0;
return 0;
}
#endif /* CONFIG_XFS_RT */
/*
* Extent tree block counting routines.
*/
/*
* Count leaf blocks given a range of extent records. Delayed allocation
* extents are not counted towards the totals.
*/
xfs_extnum_t
xfs_bmap_count_leaves(
struct xfs_ifork *ifp,
xfs_filblks_t *count)
{
struct xfs_iext_cursor icur;
struct xfs_bmbt_irec got;
xfs_extnum_t numrecs = 0;
for_each_xfs_iext(ifp, &icur, &got) {
if (!isnullstartblock(got.br_startblock)) {
*count += got.br_blockcount;
numrecs++;
}
}
return numrecs;
}
/*
* Count fsblocks of the given fork. Delayed allocation extents are
* not counted towards the totals.
*/
int
xfs_bmap_count_blocks(
struct xfs_trans *tp,
struct xfs_inode *ip,
int whichfork,
xfs_extnum_t *nextents,
xfs_filblks_t *count)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
struct xfs_btree_cur *cur;
xfs_extlen_t btblocks = 0;
int error;
*nextents = 0;
*count = 0;
if (!ifp)
return 0;
switch (ifp->if_format) {
case XFS_DINODE_FMT_BTREE:
error = xfs_iread_extents(tp, ip, whichfork);
if (error)
return error;
cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
error = xfs_btree_count_blocks(cur, &btblocks);
xfs_btree_del_cursor(cur, error);
if (error)
return error;
/*
* xfs_btree_count_blocks includes the root block contained in
* the inode fork in @btblocks, so subtract one because we're
* only interested in allocated disk blocks.
*/
*count += btblocks - 1;
fallthrough;
case XFS_DINODE_FMT_EXTENTS:
*nextents = xfs_bmap_count_leaves(ifp, count);
break;
}
return 0;
}
static int
xfs_getbmap_report_one(
struct xfs_inode *ip,
struct getbmapx *bmv,
struct kgetbmap *out,
int64_t bmv_end,
struct xfs_bmbt_irec *got)
{
struct kgetbmap *p = out + bmv->bmv_entries;
bool shared = false;
int error;
error = xfs_reflink_trim_around_shared(ip, got, &shared);
if (error)
return error;
if (isnullstartblock(got->br_startblock) ||
got->br_startblock == DELAYSTARTBLOCK) {
/*
* Take the flush completion as being a point-in-time snapshot
* where there are no delalloc extents, and if any new ones
* have been created racily, just skip them as being 'after'
* the flush and so don't get reported.
*/
if (!(bmv->bmv_iflags & BMV_IF_DELALLOC))
return 0;
p->bmv_oflags |= BMV_OF_DELALLOC;
p->bmv_block = -2;
} else {
p->bmv_block = xfs_fsb_to_db(ip, got->br_startblock);
}
if (got->br_state == XFS_EXT_UNWRITTEN &&
(bmv->bmv_iflags & BMV_IF_PREALLOC))
p->bmv_oflags |= BMV_OF_PREALLOC;
if (shared)
p->bmv_oflags |= BMV_OF_SHARED;
p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, got->br_startoff);
p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, got->br_blockcount);
bmv->bmv_offset = p->bmv_offset + p->bmv_length;
bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
bmv->bmv_entries++;
return 0;
}
static void
xfs_getbmap_report_hole(
struct xfs_inode *ip,
struct getbmapx *bmv,
struct kgetbmap *out,
int64_t bmv_end,
xfs_fileoff_t bno,
xfs_fileoff_t end)
{
struct kgetbmap *p = out + bmv->bmv_entries;
if (bmv->bmv_iflags & BMV_IF_NO_HOLES)
return;
p->bmv_block = -1;
p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, bno);
p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, end - bno);
bmv->bmv_offset = p->bmv_offset + p->bmv_length;
bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
bmv->bmv_entries++;
}
static inline bool
xfs_getbmap_full(
struct getbmapx *bmv)
{
return bmv->bmv_length == 0 || bmv->bmv_entries >= bmv->bmv_count - 1;
}
static bool
xfs_getbmap_next_rec(
struct xfs_bmbt_irec *rec,
xfs_fileoff_t total_end)
{
xfs_fileoff_t end = rec->br_startoff + rec->br_blockcount;
if (end == total_end)
return false;
rec->br_startoff += rec->br_blockcount;
if (!isnullstartblock(rec->br_startblock) &&
rec->br_startblock != DELAYSTARTBLOCK)
rec->br_startblock += rec->br_blockcount;
rec->br_blockcount = total_end - end;
return true;
}
/*
* Get inode's extents as described in bmv, and format for output.
* Calls formatter to fill the user's buffer until all extents
* are mapped, until the passed-in bmv->bmv_count slots have
* been filled, or until the formatter short-circuits the loop,
* if it is tracking filled-in extents on its own.
*/
int /* error code */
xfs_getbmap(
struct xfs_inode *ip,
struct getbmapx *bmv, /* user bmap structure */
struct kgetbmap *out)
{
struct xfs_mount *mp = ip->i_mount;
int iflags = bmv->bmv_iflags;
int whichfork, lock, error = 0;
int64_t bmv_end, max_len;
xfs_fileoff_t bno, first_bno;
struct xfs_ifork *ifp;
struct xfs_bmbt_irec got, rec;
xfs_filblks_t len;
struct xfs_iext_cursor icur;
if (bmv->bmv_iflags & ~BMV_IF_VALID)
return -EINVAL;
#ifndef DEBUG
/* Only allow CoW fork queries if we're debugging. */
if (iflags & BMV_IF_COWFORK)
return -EINVAL;
#endif
if ((iflags & BMV_IF_ATTRFORK) && (iflags & BMV_IF_COWFORK))
return -EINVAL;
if (bmv->bmv_length < -1)
return -EINVAL;
bmv->bmv_entries = 0;
if (bmv->bmv_length == 0)
return 0;
if (iflags & BMV_IF_ATTRFORK)
whichfork = XFS_ATTR_FORK;
else if (iflags & BMV_IF_COWFORK)
whichfork = XFS_COW_FORK;
else
whichfork = XFS_DATA_FORK;
xfs_ilock(ip, XFS_IOLOCK_SHARED);
switch (whichfork) {
case XFS_ATTR_FORK:
lock = xfs_ilock_attr_map_shared(ip);
if (!xfs_inode_has_attr_fork(ip))
goto out_unlock_ilock;
max_len = 1LL << 32;
break;
case XFS_COW_FORK:
lock = XFS_ILOCK_SHARED;
xfs_ilock(ip, lock);
/* No CoW fork? Just return */
if (!xfs_ifork_ptr(ip, whichfork))
goto out_unlock_ilock;
if (xfs_get_cowextsz_hint(ip))
max_len = mp->m_super->s_maxbytes;
else
max_len = XFS_ISIZE(ip);
break;
case XFS_DATA_FORK:
if (!(iflags & BMV_IF_DELALLOC) &&
(ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_disk_size)) {
error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
if (error)
goto out_unlock_iolock;
/*
* Even after flushing the inode, there can still be
* delalloc blocks on the inode beyond EOF due to
* speculative preallocation. These are not removed
* until the release function is called or the inode
* is inactivated. Hence we cannot assert here that
* ip->i_delayed_blks == 0.
*/
}
if (xfs_get_extsz_hint(ip) ||
(ip->i_diflags &
(XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))
max_len = mp->m_super->s_maxbytes;
else
max_len = XFS_ISIZE(ip);
lock = xfs_ilock_data_map_shared(ip);
break;
}
ifp = xfs_ifork_ptr(ip, whichfork);
switch (ifp->if_format) {
case XFS_DINODE_FMT_EXTENTS:
case XFS_DINODE_FMT_BTREE:
break;
case XFS_DINODE_FMT_LOCAL:
/* Local format inode forks report no extents. */
goto out_unlock_ilock;
default:
error = -EINVAL;
goto out_unlock_ilock;
}
if (bmv->bmv_length == -1) {
max_len = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, max_len));
bmv->bmv_length = max(0LL, max_len - bmv->bmv_offset);
}
bmv_end = bmv->bmv_offset + bmv->bmv_length;
first_bno = bno = XFS_BB_TO_FSBT(mp, bmv->bmv_offset);
len = XFS_BB_TO_FSB(mp, bmv->bmv_length);
error = xfs_iread_extents(NULL, ip, whichfork);
if (error)
goto out_unlock_ilock;
if (!xfs_iext_lookup_extent(ip, ifp, bno, &icur, &got)) {
/*
* Report a whole-file hole if the delalloc flag is set to
* stay compatible with the old implementation.
*/
if (iflags & BMV_IF_DELALLOC)
xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
XFS_B_TO_FSB(mp, XFS_ISIZE(ip)));
goto out_unlock_ilock;
}
while (!xfs_getbmap_full(bmv)) {
xfs_trim_extent(&got, first_bno, len);
/*
* Report an entry for a hole if this extent doesn't directly
* follow the previous one.
*/
if (got.br_startoff > bno) {
xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
got.br_startoff);
if (xfs_getbmap_full(bmv))
break;
}
/*
* In order to report shared extents accurately, we report each
* distinct shared / unshared part of a single bmbt record with
* an individual getbmapx record.
*/
bno = got.br_startoff + got.br_blockcount;
rec = got;
do {
error = xfs_getbmap_report_one(ip, bmv, out, bmv_end,
&rec);
if (error || xfs_getbmap_full(bmv))
goto out_unlock_ilock;
} while (xfs_getbmap_next_rec(&rec, bno));
if (!xfs_iext_next_extent(ifp, &icur, &got)) {
xfs_fileoff_t end = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
if (bmv->bmv_entries > 0)
out[bmv->bmv_entries - 1].bmv_oflags |=
BMV_OF_LAST;
if (whichfork != XFS_ATTR_FORK && bno < end &&
!xfs_getbmap_full(bmv)) {
xfs_getbmap_report_hole(ip, bmv, out, bmv_end,
bno, end);
}
break;
}
if (bno >= first_bno + len)
break;
}
out_unlock_ilock:
xfs_iunlock(ip, lock);
out_unlock_iolock:
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return error;
}
/*
* Dead simple method of punching delalyed allocation blocks from a range in
* the inode. This will always punch out both the start and end blocks, even
* if the ranges only partially overlap them, so it is up to the caller to
* ensure that partial blocks are not passed in.
*/
int
xfs_bmap_punch_delalloc_range(
struct xfs_inode *ip,
xfs_off_t start_byte,
xfs_off_t end_byte)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_ifork *ifp = &ip->i_df;
xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, start_byte);
xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, end_byte);
struct xfs_bmbt_irec got, del;
struct xfs_iext_cursor icur;
int error = 0;
ASSERT(!xfs_need_iread_extents(ifp));
xfs_ilock(ip, XFS_ILOCK_EXCL);
if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))
goto out_unlock;
while (got.br_startoff + got.br_blockcount > start_fsb) {
del = got;
xfs_trim_extent(&del, start_fsb, end_fsb - start_fsb);
/*
* A delete can push the cursor forward. Step back to the
* previous extent on non-delalloc or extents outside the
* target range.
*/
if (!del.br_blockcount ||
!isnullstartblock(del.br_startblock)) {
if (!xfs_iext_prev_extent(ifp, &icur, &got))
break;
continue;
}
error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur,
&got, &del);
if (error || !xfs_iext_get_extent(ifp, &icur, &got))
break;
}
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
/*
* Test whether it is appropriate to check an inode for and free post EOF
* blocks. The 'force' parameter determines whether we should also consider
* regular files that are marked preallocated or append-only.
*/
bool
xfs_can_free_eofblocks(
struct xfs_inode *ip,
bool force)
{
struct xfs_bmbt_irec imap;
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t end_fsb;
xfs_fileoff_t last_fsb;
int nimaps = 1;
int error;
/*
* Caller must either hold the exclusive io lock; or be inactivating
* the inode, which guarantees there are no other users of the inode.
*/
ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL) ||
(VFS_I(ip)->i_state & I_FREEING));
/* prealloc/delalloc exists only on regular files */
if (!S_ISREG(VFS_I(ip)->i_mode))
return false;
/*
* Zero sized files with no cached pages and delalloc blocks will not
* have speculative prealloc/delalloc blocks to remove.
*/
if (VFS_I(ip)->i_size == 0 &&
VFS_I(ip)->i_mapping->nrpages == 0 &&
ip->i_delayed_blks == 0)
return false;
/* If we haven't read in the extent list, then don't do it now. */
if (xfs_need_iread_extents(&ip->i_df))
return false;
/*
* Do not free real preallocated or append-only files unless the file
* has delalloc blocks and we are forced to remove them.
*/
if (ip->i_diflags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND))
if (!force || ip->i_delayed_blks == 0)
return false;
/*
* Do not try to free post-EOF blocks if EOF is beyond the end of the
* range supported by the page cache, because the truncation will loop
* forever.
*/
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip));
if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1)
end_fsb = roundup_64(end_fsb, mp->m_sb.sb_rextsize);
last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
if (last_fsb <= end_fsb)
return false;
/*
* Look up the mapping for the first block past EOF. If we can't find
* it, there's nothing to free.
*/
xfs_ilock(ip, XFS_ILOCK_SHARED);
error = xfs_bmapi_read(ip, end_fsb, last_fsb - end_fsb, &imap, &nimaps,
0);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (error || nimaps == 0)
return false;
/*
* If there's a real mapping there or there are delayed allocation
* reservations, then we have post-EOF blocks to try to free.
*/
return imap.br_startblock != HOLESTARTBLOCK || ip->i_delayed_blks;
}
/*
* This is called to free any blocks beyond eof. The caller must hold
* IOLOCK_EXCL unless we are in the inode reclaim path and have the only
* reference to the inode.
*/
int
xfs_free_eofblocks(
struct xfs_inode *ip)
{
struct xfs_trans *tp;
struct xfs_mount *mp = ip->i_mount;
int error;
/* Attach the dquots to the inode up front. */
error = xfs_qm_dqattach(ip);
if (error)
return error;
/* Wait on dio to ensure i_size has settled. */
inode_dio_wait(VFS_I(ip));
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
if (error) {
ASSERT(xfs_is_shutdown(mp));
return error;
}
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
/*
* Do not update the on-disk file size. If we update the on-disk file
* size and then the system crashes before the contents of the file are
* flushed to disk then the files may be full of holes (ie NULL files
* bug).
*/
error = xfs_itruncate_extents_flags(&tp, ip, XFS_DATA_FORK,
XFS_ISIZE(ip), XFS_BMAPI_NODISCARD);
if (error)
goto err_cancel;
error = xfs_trans_commit(tp);
if (error)
goto out_unlock;
xfs_inode_clear_eofblocks_tag(ip);
goto out_unlock;
err_cancel:
/*
* If we get an error at this point we simply don't
* bother truncating the file.
*/
xfs_trans_cancel(tp);
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
int
xfs_alloc_file_space(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t len)
{
xfs_mount_t *mp = ip->i_mount;
xfs_off_t count;
xfs_filblks_t allocated_fsb;
xfs_filblks_t allocatesize_fsb;
xfs_extlen_t extsz, temp;
xfs_fileoff_t startoffset_fsb;
xfs_fileoff_t endoffset_fsb;
int nimaps;
int rt;
xfs_trans_t *tp;
xfs_bmbt_irec_t imaps[1], *imapp;
int error;
trace_xfs_alloc_file_space(ip);
if (xfs_is_shutdown(mp))
return -EIO;
error = xfs_qm_dqattach(ip);
if (error)
return error;
if (len <= 0)
return -EINVAL;
rt = XFS_IS_REALTIME_INODE(ip);
extsz = xfs_get_extsz_hint(ip);
count = len;
imapp = &imaps[0];
nimaps = 1;
startoffset_fsb = XFS_B_TO_FSBT(mp, offset);
endoffset_fsb = XFS_B_TO_FSB(mp, offset + count);
allocatesize_fsb = endoffset_fsb - startoffset_fsb;
/*
* Allocate file space until done or until there is an error
*/
while (allocatesize_fsb && !error) {
xfs_fileoff_t s, e;
unsigned int dblocks, rblocks, resblks;
/*
* Determine space reservations for data/realtime.
*/
if (unlikely(extsz)) {
s = startoffset_fsb;
do_div(s, extsz);
s *= extsz;
e = startoffset_fsb + allocatesize_fsb;
div_u64_rem(startoffset_fsb, extsz, &temp);
if (temp)
e += temp;
div_u64_rem(e, extsz, &temp);
if (temp)
e += extsz - temp;
} else {
s = 0;
e = allocatesize_fsb;
}
/*
* The transaction reservation is limited to a 32-bit block
* count, hence we need to limit the number of blocks we are
* trying to reserve to avoid an overflow. We can't allocate
* more than @nimaps extents, and an extent is limited on disk
* to XFS_BMBT_MAX_EXTLEN (21 bits), so use that to enforce the
* limit.
*/
resblks = min_t(xfs_fileoff_t, (e - s),
(XFS_MAX_BMBT_EXTLEN * nimaps));
if (unlikely(rt)) {
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
rblocks = resblks;
} else {
dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resblks);
rblocks = 0;
}
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
dblocks, rblocks, false, &tp);
if (error)
break;
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_ADD_NOSPLIT_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip,
XFS_IEXT_ADD_NOSPLIT_CNT);
if (error)
goto error;
error = xfs_bmapi_write(tp, ip, startoffset_fsb,
allocatesize_fsb, XFS_BMAPI_PREALLOC, 0, imapp,
&nimaps);
if (error)
goto error;
ip->i_diflags |= XFS_DIFLAG_PREALLOC;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
error = xfs_trans_commit(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
if (error)
break;
allocated_fsb = imapp->br_blockcount;
if (nimaps == 0) {
error = -ENOSPC;
break;
}
startoffset_fsb += allocated_fsb;
allocatesize_fsb -= allocated_fsb;
}
return error;
error:
xfs_trans_cancel(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
static int
xfs_unmap_extent(
struct xfs_inode *ip,
xfs_fileoff_t startoffset_fsb,
xfs_filblks_t len_fsb,
int *done)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
uint resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
int error;
error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
false, &tp);
if (error)
return error;
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_PUNCH_HOLE_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
if (error)
goto out_trans_cancel;
error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, done);
if (error)
goto out_trans_cancel;
error = xfs_trans_commit(tp);
out_unlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
goto out_unlock;
}
/* Caller must first wait for the completion of any pending DIOs if required. */
int
xfs_flush_unmap_range(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t len)
{
struct xfs_mount *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);
xfs_off_t rounding, start, end;
int error;
rounding = max_t(xfs_off_t, mp->m_sb.sb_blocksize, PAGE_SIZE);
start = round_down(offset, rounding);
end = round_up(offset + len, rounding) - 1;
error = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (error)
return error;
truncate_pagecache_range(inode, start, end);
return 0;
}
int
xfs_free_file_space(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t len)
{
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t startoffset_fsb;
xfs_fileoff_t endoffset_fsb;
int done = 0, error;
trace_xfs_free_file_space(ip);
error = xfs_qm_dqattach(ip);
if (error)
return error;
if (len <= 0) /* if nothing being freed */
return 0;
startoffset_fsb = XFS_B_TO_FSB(mp, offset);
endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
/* We can only free complete realtime extents. */
if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) {
startoffset_fsb = roundup_64(startoffset_fsb,
mp->m_sb.sb_rextsize);
endoffset_fsb = rounddown_64(endoffset_fsb,
mp->m_sb.sb_rextsize);
}
/*
* Need to zero the stuff we're not freeing, on disk.
*/
if (endoffset_fsb > startoffset_fsb) {
while (!done) {
error = xfs_unmap_extent(ip, startoffset_fsb,
endoffset_fsb - startoffset_fsb, &done);
if (error)
return error;
}
}
/*
* Now that we've unmap all full blocks we'll have to zero out any
* partial block at the beginning and/or end. xfs_zero_range is smart
* enough to skip any holes, including those we just created, but we
* must take care not to zero beyond EOF and enlarge i_size.
*/
if (offset >= XFS_ISIZE(ip))
return 0;
if (offset + len > XFS_ISIZE(ip))
len = XFS_ISIZE(ip) - offset;
error = xfs_zero_range(ip, offset, len, NULL);
if (error)
return error;
/*
* If we zeroed right up to EOF and EOF straddles a page boundary we
* must make sure that the post-EOF area is also zeroed because the
* page could be mmap'd and xfs_zero_range doesn't do that for us.
* Writeback of the eof page will do this, albeit clumsily.
*/
if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
round_down(offset + len, PAGE_SIZE), LLONG_MAX);
}
return error;
}
static int
xfs_prepare_shift(
struct xfs_inode *ip,
loff_t offset)
{
struct xfs_mount *mp = ip->i_mount;
int error;
/*
* Trim eofblocks to avoid shifting uninitialized post-eof preallocation
* into the accessible region of the file.
*/
if (xfs_can_free_eofblocks(ip, true)) {
error = xfs_free_eofblocks(ip);
if (error)
return error;
}
/*
* Shift operations must stabilize the start block offset boundary along
* with the full range of the operation. If we don't, a COW writeback
* completion could race with an insert, front merge with the start
* extent (after split) during the shift and corrupt the file. Start
* with the block just prior to the start to stabilize the boundary.
*/
offset = round_down(offset, mp->m_sb.sb_blocksize);
if (offset)
offset -= mp->m_sb.sb_blocksize;
/*
* Writeback and invalidate cache for the remainder of the file as we're
* about to shift down every extent from offset to EOF.
*/
error = xfs_flush_unmap_range(ip, offset, XFS_ISIZE(ip));
if (error)
return error;
/*
* Clean out anything hanging around in the cow fork now that
* we've flushed all the dirty data out to disk to avoid having
* CoW extents at the wrong offsets.
*/
if (xfs_inode_has_cow_data(ip)) {
error = xfs_reflink_cancel_cow_range(ip, offset, NULLFILEOFF,
true);
if (error)
return error;
}
return 0;
}
/*
* xfs_collapse_file_space()
* This routine frees disk space and shift extent for the given file.
* The first thing we do is to free data blocks in the specified range
* by calling xfs_free_file_space(). It would also sync dirty data
* and invalidate page cache over the region on which collapse range
* is working. And Shift extent records to the left to cover a hole.
* RETURNS:
* 0 on success
* errno on error
*
*/
int
xfs_collapse_file_space(
struct xfs_inode *ip,
xfs_off_t offset,
xfs_off_t len)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int error;
xfs_fileoff_t next_fsb = XFS_B_TO_FSB(mp, offset + len);
xfs_fileoff_t shift_fsb = XFS_B_TO_FSB(mp, len);
bool done = false;
ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
trace_xfs_collapse_file_space(ip);
error = xfs_free_file_space(ip, offset, len);
if (error)
return error;
error = xfs_prepare_shift(ip, offset);
if (error)
return error;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
while (!done) {
error = xfs_bmap_collapse_extents(tp, ip, &next_fsb, shift_fsb,
&done);
if (error)
goto out_trans_cancel;
if (done)
break;
/* finish any deferred frees and roll the transaction */
error = xfs_defer_finish(&tp);
if (error)
goto out_trans_cancel;
}
error = xfs_trans_commit(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
/*
* xfs_insert_file_space()
* This routine create hole space by shifting extents for the given file.
* The first thing we do is to sync dirty data and invalidate page cache
* over the region on which insert range is working. And split an extent
* to two extents at given offset by calling xfs_bmap_split_extent.
* And shift all extent records which are laying between [offset,
* last allocated extent] to the right to reserve hole range.
* RETURNS:
* 0 on success
* errno on error
*/
int
xfs_insert_file_space(
struct xfs_inode *ip,
loff_t offset,
loff_t len)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int error;
xfs_fileoff_t stop_fsb = XFS_B_TO_FSB(mp, offset);
xfs_fileoff_t next_fsb = NULLFSBLOCK;
xfs_fileoff_t shift_fsb = XFS_B_TO_FSB(mp, len);
bool done = false;
ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
trace_xfs_insert_file_space(ip);
error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
if (error)
return error;
error = xfs_prepare_shift(ip, offset);
if (error)
return error;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write,
XFS_DIOSTRAT_SPACE_RES(mp, 0), 0, 0, &tp);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
XFS_IEXT_PUNCH_HOLE_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
if (error)
goto out_trans_cancel;
/*
* The extent shifting code works on extent granularity. So, if stop_fsb
* is not the starting block of extent, we need to split the extent at
* stop_fsb.
*/
error = xfs_bmap_split_extent(tp, ip, stop_fsb);
if (error)
goto out_trans_cancel;
do {
error = xfs_defer_finish(&tp);
if (error)
goto out_trans_cancel;
error = xfs_bmap_insert_extents(tp, ip, &next_fsb, shift_fsb,
&done, stop_fsb);
if (error)
goto out_trans_cancel;
} while (!done);
error = xfs_trans_commit(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
/*
* We need to check that the format of the data fork in the temporary inode is
* valid for the target inode before doing the swap. This is not a problem with
* attr1 because of the fixed fork offset, but attr2 has a dynamically sized
* data fork depending on the space the attribute fork is taking so we can get
* invalid formats on the target inode.
*
* E.g. target has space for 7 extents in extent format, temp inode only has
* space for 6. If we defragment down to 7 extents, then the tmp format is a
* btree, but when swapped it needs to be in extent format. Hence we can't just
* blindly swap data forks on attr2 filesystems.
*
* Note that we check the swap in both directions so that we don't end up with
* a corrupt temporary inode, either.
*
* Note that fixing the way xfs_fsr sets up the attribute fork in the source
* inode will prevent this situation from occurring, so all we do here is
* reject and log the attempt. basically we are putting the responsibility on
* userspace to get this right.
*/
static int
xfs_swap_extents_check_format(
struct xfs_inode *ip, /* target inode */
struct xfs_inode *tip) /* tmp inode */
{
struct xfs_ifork *ifp = &ip->i_df;
struct xfs_ifork *tifp = &tip->i_df;
/* User/group/project quota ids must match if quotas are enforced. */
if (XFS_IS_QUOTA_ON(ip->i_mount) &&
(!uid_eq(VFS_I(ip)->i_uid, VFS_I(tip)->i_uid) ||
!gid_eq(VFS_I(ip)->i_gid, VFS_I(tip)->i_gid) ||
ip->i_projid != tip->i_projid))
return -EINVAL;
/* Should never get a local format */
if (ifp->if_format == XFS_DINODE_FMT_LOCAL ||
tifp->if_format == XFS_DINODE_FMT_LOCAL)
return -EINVAL;
/*
* if the target inode has less extents that then temporary inode then
* why did userspace call us?
*/
if (ifp->if_nextents < tifp->if_nextents)
return -EINVAL;
/*
* If we have to use the (expensive) rmap swap method, we can
* handle any number of extents and any format.
*/
if (xfs_has_rmapbt(ip->i_mount))
return 0;
/*
* if the target inode is in extent form and the temp inode is in btree
* form then we will end up with the target inode in the wrong format
* as we already know there are less extents in the temp inode.
*/
if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
tifp->if_format == XFS_DINODE_FMT_BTREE)
return -EINVAL;
/* Check temp in extent form to max in target */
if (tifp->if_format == XFS_DINODE_FMT_EXTENTS &&
tifp->if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
return -EINVAL;
/* Check target in extent form to max in temp */
if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
ifp->if_nextents > XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
return -EINVAL;
/*
* If we are in a btree format, check that the temp root block will fit
* in the target and that it has enough extents to be in btree format
* in the target.
*
* Note that we have to be careful to allow btree->extent conversions
* (a common defrag case) which will occur when the temp inode is in
* extent format...
*/
if (tifp->if_format == XFS_DINODE_FMT_BTREE) {
if (xfs_inode_has_attr_fork(ip) &&
XFS_BMAP_BMDR_SPACE(tifp->if_broot) > xfs_inode_fork_boff(ip))
return -EINVAL;
if (tifp->if_nextents <= XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
return -EINVAL;
}
/* Reciprocal target->temp btree format checks */
if (ifp->if_format == XFS_DINODE_FMT_BTREE) {
if (xfs_inode_has_attr_fork(tip) &&
XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > xfs_inode_fork_boff(tip))
return -EINVAL;
if (ifp->if_nextents <= XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
return -EINVAL;
}
return 0;
}
static int
xfs_swap_extent_flush(
struct xfs_inode *ip)
{
int error;
error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
if (error)
return error;
truncate_pagecache_range(VFS_I(ip), 0, -1);
/* Verify O_DIRECT for ftmp */
if (VFS_I(ip)->i_mapping->nrpages)
return -EINVAL;
return 0;
}
/*
* Move extents from one file to another, when rmap is enabled.
*/
STATIC int
xfs_swap_extent_rmap(
struct xfs_trans **tpp,
struct xfs_inode *ip,
struct xfs_inode *tip)
{
struct xfs_trans *tp = *tpp;
struct xfs_bmbt_irec irec;
struct xfs_bmbt_irec uirec;
struct xfs_bmbt_irec tirec;
xfs_fileoff_t offset_fsb;
xfs_fileoff_t end_fsb;
xfs_filblks_t count_fsb;
int error;
xfs_filblks_t ilen;
xfs_filblks_t rlen;
int nimaps;
uint64_t tip_flags2;
/*
* If the source file has shared blocks, we must flag the donor
* file as having shared blocks so that we get the shared-block
* rmap functions when we go to fix up the rmaps. The flags
* will be switch for reals later.
*/
tip_flags2 = tip->i_diflags2;
if (ip->i_diflags2 & XFS_DIFLAG2_REFLINK)
tip->i_diflags2 |= XFS_DIFLAG2_REFLINK;
offset_fsb = 0;
end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip)));
count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
while (count_fsb) {
/* Read extent from the donor file */
nimaps = 1;
error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec,
&nimaps, 0);
if (error)
goto out;
ASSERT(nimaps == 1);
ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
trace_xfs_swap_extent_rmap_remap(tip, &tirec);
ilen = tirec.br_blockcount;
/* Unmap the old blocks in the source file. */
while (tirec.br_blockcount) {
ASSERT(tp->t_highest_agno == NULLAGNUMBER);
trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
/* Read extent from the source file */
nimaps = 1;
error = xfs_bmapi_read(ip, tirec.br_startoff,
tirec.br_blockcount, &irec,
&nimaps, 0);
if (error)
goto out;
ASSERT(nimaps == 1);
ASSERT(tirec.br_startoff == irec.br_startoff);
trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
/* Trim the extent. */
uirec = tirec;
uirec.br_blockcount = rlen = min_t(xfs_filblks_t,
tirec.br_blockcount,
irec.br_blockcount);
trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
if (xfs_bmap_is_real_extent(&uirec)) {
error = xfs_iext_count_may_overflow(ip,
XFS_DATA_FORK,
XFS_IEXT_SWAP_RMAP_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip,
XFS_IEXT_SWAP_RMAP_CNT);
if (error)
goto out;
}
if (xfs_bmap_is_real_extent(&irec)) {
error = xfs_iext_count_may_overflow(tip,
XFS_DATA_FORK,
XFS_IEXT_SWAP_RMAP_CNT);
if (error == -EFBIG)
error = xfs_iext_count_upgrade(tp, ip,
XFS_IEXT_SWAP_RMAP_CNT);
if (error)
goto out;
}
/* Remove the mapping from the donor file. */
xfs_bmap_unmap_extent(tp, tip, &uirec);
/* Remove the mapping from the source file. */
xfs_bmap_unmap_extent(tp, ip, &irec);
/* Map the donor file's blocks into the source file. */
xfs_bmap_map_extent(tp, ip, &uirec);
/* Map the source file's blocks into the donor file. */
xfs_bmap_map_extent(tp, tip, &irec);
error = xfs_defer_finish(tpp);
tp = *tpp;
if (error)
goto out;
tirec.br_startoff += rlen;
if (tirec.br_startblock != HOLESTARTBLOCK &&
tirec.br_startblock != DELAYSTARTBLOCK)
tirec.br_startblock += rlen;
tirec.br_blockcount -= rlen;
}
/* Roll on... */
count_fsb -= ilen;
offset_fsb += ilen;
}
tip->i_diflags2 = tip_flags2;
return 0;
out:
trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
tip->i_diflags2 = tip_flags2;
return error;
}
/* Swap the extents of two files by swapping data forks. */
STATIC int
xfs_swap_extent_forks(
struct xfs_trans *tp,
struct xfs_inode *ip,
struct xfs_inode *tip,
int *src_log_flags,
int *target_log_flags)
{
xfs_filblks_t aforkblks = 0;
xfs_filblks_t taforkblks = 0;
xfs_extnum_t junk;
uint64_t tmp;
int error;
/*
* Count the number of extended attribute blocks
*/
if (xfs_inode_has_attr_fork(ip) && ip->i_af.if_nextents > 0 &&
ip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &junk,
&aforkblks);
if (error)
return error;
}
if (xfs_inode_has_attr_fork(tip) && tip->i_af.if_nextents > 0 &&
tip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK, &junk,
&taforkblks);
if (error)
return error;
}
/*
* Btree format (v3) inodes have the inode number stamped in the bmbt
* block headers. We can't start changing the bmbt blocks until the
* inode owner change is logged so recovery does the right thing in the
* event of a crash. Set the owner change log flags now and leave the
* bmbt scan as the last step.
*/
if (xfs_has_v3inodes(ip->i_mount)) {
if (ip->i_df.if_format == XFS_DINODE_FMT_BTREE)
(*target_log_flags) |= XFS_ILOG_DOWNER;
if (tip->i_df.if_format == XFS_DINODE_FMT_BTREE)
(*src_log_flags) |= XFS_ILOG_DOWNER;
}
/*
* Swap the data forks of the inodes
*/
swap(ip->i_df, tip->i_df);
/*
* Fix the on-disk inode values
*/
tmp = (uint64_t)ip->i_nblocks;
ip->i_nblocks = tip->i_nblocks - taforkblks + aforkblks;
tip->i_nblocks = tmp + taforkblks - aforkblks;
/*
* The extents in the source inode could still contain speculative
* preallocation beyond EOF (e.g. the file is open but not modified
* while defrag is in progress). In that case, we need to copy over the
* number of delalloc blocks the data fork in the source inode is
* tracking beyond EOF so that when the fork is truncated away when the
* temporary inode is unlinked we don't underrun the i_delayed_blks
* counter on that inode.
*/
ASSERT(tip->i_delayed_blks == 0);
tip->i_delayed_blks = ip->i_delayed_blks;
ip->i_delayed_blks = 0;
switch (ip->i_df.if_format) {
case XFS_DINODE_FMT_EXTENTS:
(*src_log_flags) |= XFS_ILOG_DEXT;
break;
case XFS_DINODE_FMT_BTREE:
ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
(*src_log_flags & XFS_ILOG_DOWNER));
(*src_log_flags) |= XFS_ILOG_DBROOT;
break;
}
switch (tip->i_df.if_format) {
case XFS_DINODE_FMT_EXTENTS:
(*target_log_flags) |= XFS_ILOG_DEXT;
break;
case XFS_DINODE_FMT_BTREE:
(*target_log_flags) |= XFS_ILOG_DBROOT;
ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
(*target_log_flags & XFS_ILOG_DOWNER));
break;
}
return 0;
}
/*
* Fix up the owners of the bmbt blocks to refer to the current inode. The
* change owner scan attempts to order all modified buffers in the current
* transaction. In the event of ordered buffer failure, the offending buffer is
* physically logged as a fallback and the scan returns -EAGAIN. We must roll
* the transaction in this case to replenish the fallback log reservation and
* restart the scan. This process repeats until the scan completes.
*/
static int
xfs_swap_change_owner(
struct xfs_trans **tpp,
struct xfs_inode *ip,
struct xfs_inode *tmpip)
{
int error;
struct xfs_trans *tp = *tpp;
do {
error = xfs_bmbt_change_owner(tp, ip, XFS_DATA_FORK, ip->i_ino,
NULL);
/* success or fatal error */
if (error != -EAGAIN)
break;
error = xfs_trans_roll(tpp);
if (error)
break;
tp = *tpp;
/*
* Redirty both inodes so they can relog and keep the log tail
* moving forward.
*/
xfs_trans_ijoin(tp, ip, 0);
xfs_trans_ijoin(tp, tmpip, 0);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
xfs_trans_log_inode(tp, tmpip, XFS_ILOG_CORE);
} while (true);
return error;
}
int
xfs_swap_extents(
struct xfs_inode *ip, /* target inode */
struct xfs_inode *tip, /* tmp inode */
struct xfs_swapext *sxp)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
struct xfs_bstat *sbp = &sxp->sx_stat;
int src_log_flags, target_log_flags;
int error = 0;
uint64_t f;
int resblks = 0;
unsigned int flags = 0;
struct timespec64 ctime;
/*
* Lock the inodes against other IO, page faults and truncate to
* begin with. Then we can ensure the inodes are flushed and have no
* page cache safely. Once we have done this we can take the ilocks and
* do the rest of the checks.
*/
lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
filemap_invalidate_lock_two(VFS_I(ip)->i_mapping,
VFS_I(tip)->i_mapping);
/* Verify that both files have the same format */
if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
error = -EINVAL;
goto out_unlock;
}
/* Verify both files are either real-time or non-realtime */
if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
error = -EINVAL;
goto out_unlock;
}
error = xfs_qm_dqattach(ip);
if (error)
goto out_unlock;
error = xfs_qm_dqattach(tip);
if (error)
goto out_unlock;
error = xfs_swap_extent_flush(ip);
if (error)
goto out_unlock;
error = xfs_swap_extent_flush(tip);
if (error)
goto out_unlock;
if (xfs_inode_has_cow_data(tip)) {
error = xfs_reflink_cancel_cow_range(tip, 0, NULLFILEOFF, true);
if (error)
goto out_unlock;
}
/*
* Extent "swapping" with rmap requires a permanent reservation and
* a block reservation because it's really just a remap operation
* performed with log redo items!
*/
if (xfs_has_rmapbt(mp)) {
int w = XFS_DATA_FORK;
uint32_t ipnext = ip->i_df.if_nextents;
uint32_t tipnext = tip->i_df.if_nextents;
/*
* Conceptually this shouldn't affect the shape of either bmbt,
* but since we atomically move extents one by one, we reserve
* enough space to rebuild both trees.
*/
resblks = XFS_SWAP_RMAP_SPACE_RES(mp, ipnext, w);
resblks += XFS_SWAP_RMAP_SPACE_RES(mp, tipnext, w);
/*
* If either inode straddles a bmapbt block allocation boundary,
* the rmapbt algorithm triggers repeated allocs and frees as
* extents are remapped. This can exhaust the block reservation
* prematurely and cause shutdown. Return freed blocks to the
* transaction reservation to counter this behavior.
*/
flags |= XFS_TRANS_RES_FDBLKS;
}
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, flags,
&tp);
if (error)
goto out_unlock;
/*
* Lock and join the inodes to the tansaction so that transaction commit
* or cancel will unlock the inodes from this point onwards.
*/
xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, 0);
xfs_trans_ijoin(tp, tip, 0);
/* Verify all data are being swapped */
if (sxp->sx_offset != 0 ||
sxp->sx_length != ip->i_disk_size ||
sxp->sx_length != tip->i_disk_size) {
error = -EFAULT;
goto out_trans_cancel;
}
trace_xfs_swap_extent_before(ip, 0);
trace_xfs_swap_extent_before(tip, 1);
/* check inode formats now that data is flushed */
error = xfs_swap_extents_check_format(ip, tip);
if (error) {
xfs_notice(mp,
"%s: inode 0x%llx format is incompatible for exchanging.",
__func__, ip->i_ino);
goto out_trans_cancel;
}
/*
* Compare the current change & modify times with that
* passed in. If they differ, we abort this swap.
* This is the mechanism used to ensure the calling
* process that the file was not changed out from
* under it.
*/
ctime = inode_get_ctime(VFS_I(ip));
if ((sbp->bs_ctime.tv_sec != ctime.tv_sec) ||
(sbp->bs_ctime.tv_nsec != ctime.tv_nsec) ||
(sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
(sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
error = -EBUSY;
goto out_trans_cancel;
}
/*
* Note the trickiness in setting the log flags - we set the owner log
* flag on the opposite inode (i.e. the inode we are setting the new
* owner to be) because once we swap the forks and log that, log
* recovery is going to see the fork as owned by the swapped inode,
* not the pre-swapped inodes.
*/
src_log_flags = XFS_ILOG_CORE;
target_log_flags = XFS_ILOG_CORE;
if (xfs_has_rmapbt(mp))
error = xfs_swap_extent_rmap(&tp, ip, tip);
else
error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
&target_log_flags);
if (error)
goto out_trans_cancel;
/* Do we have to swap reflink flags? */
if ((ip->i_diflags2 & XFS_DIFLAG2_REFLINK) ^
(tip->i_diflags2 & XFS_DIFLAG2_REFLINK)) {
f = ip->i_diflags2 & XFS_DIFLAG2_REFLINK;
ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
ip->i_diflags2 |= tip->i_diflags2 & XFS_DIFLAG2_REFLINK;
tip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
tip->i_diflags2 |= f & XFS_DIFLAG2_REFLINK;
}
/* Swap the cow forks. */
if (xfs_has_reflink(mp)) {
ASSERT(!ip->i_cowfp ||
ip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
ASSERT(!tip->i_cowfp ||
tip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
swap(ip->i_cowfp, tip->i_cowfp);
if (ip->i_cowfp && ip->i_cowfp->if_bytes)
xfs_inode_set_cowblocks_tag(ip);
else
xfs_inode_clear_cowblocks_tag(ip);
if (tip->i_cowfp && tip->i_cowfp->if_bytes)
xfs_inode_set_cowblocks_tag(tip);
else
xfs_inode_clear_cowblocks_tag(tip);
}
xfs_trans_log_inode(tp, ip, src_log_flags);
xfs_trans_log_inode(tp, tip, target_log_flags);
/*
* The extent forks have been swapped, but crc=1,rmapbt=0 filesystems
* have inode number owner values in the bmbt blocks that still refer to
* the old inode. Scan each bmbt to fix up the owner values with the
* inode number of the current inode.
*/
if (src_log_flags & XFS_ILOG_DOWNER) {
error = xfs_swap_change_owner(&tp, ip, tip);
if (error)
goto out_trans_cancel;
}
if (target_log_flags & XFS_ILOG_DOWNER) {
error = xfs_swap_change_owner(&tp, tip, ip);
if (error)
goto out_trans_cancel;
}
/*
* If this is a synchronous mount, make sure that the
* transaction goes to disk before returning to the user.
*/
if (xfs_has_wsync(mp))
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
trace_xfs_swap_extent_after(ip, 0);
trace_xfs_swap_extent_after(tip, 1);
out_unlock_ilock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_iunlock(tip, XFS_ILOCK_EXCL);
out_unlock:
filemap_invalidate_unlock_two(VFS_I(ip)->i_mapping,
VFS_I(tip)->i_mapping);
unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
goto out_unlock_ilock;
}
| linux-master | fs/xfs/xfs_bmap_util.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_inode_item.h"
#include "xfs_quota.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_bmap_util.h"
#include "xfs_dquot_item.h"
#include "xfs_dquot.h"
#include "xfs_reflink.h"
#include "xfs_ialloc.h"
#include "xfs_ag.h"
#include "xfs_log_priv.h"
#include <linux/iversion.h>
/* Radix tree tags for incore inode tree. */
/* inode is to be reclaimed */
#define XFS_ICI_RECLAIM_TAG 0
/* Inode has speculative preallocations (posteof or cow) to clean. */
#define XFS_ICI_BLOCKGC_TAG 1
/*
* The goal for walking incore inodes. These can correspond with incore inode
* radix tree tags when convenient. Avoid existing XFS_IWALK namespace.
*/
enum xfs_icwalk_goal {
/* Goals directly associated with tagged inodes. */
XFS_ICWALK_BLOCKGC = XFS_ICI_BLOCKGC_TAG,
XFS_ICWALK_RECLAIM = XFS_ICI_RECLAIM_TAG,
};
static int xfs_icwalk(struct xfs_mount *mp,
enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
static int xfs_icwalk_ag(struct xfs_perag *pag,
enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
/*
* Private inode cache walk flags for struct xfs_icwalk. Must not
* coincide with XFS_ICWALK_FLAGS_VALID.
*/
/* Stop scanning after icw_scan_limit inodes. */
#define XFS_ICWALK_FLAG_SCAN_LIMIT (1U << 28)
#define XFS_ICWALK_FLAG_RECLAIM_SICK (1U << 27)
#define XFS_ICWALK_FLAG_UNION (1U << 26) /* union filter algorithm */
#define XFS_ICWALK_PRIVATE_FLAGS (XFS_ICWALK_FLAG_SCAN_LIMIT | \
XFS_ICWALK_FLAG_RECLAIM_SICK | \
XFS_ICWALK_FLAG_UNION)
/*
* Allocate and initialise an xfs_inode.
*/
struct xfs_inode *
xfs_inode_alloc(
struct xfs_mount *mp,
xfs_ino_t ino)
{
struct xfs_inode *ip;
/*
* XXX: If this didn't occur in transactions, we could drop GFP_NOFAIL
* and return NULL here on ENOMEM.
*/
ip = alloc_inode_sb(mp->m_super, xfs_inode_cache, GFP_KERNEL | __GFP_NOFAIL);
if (inode_init_always(mp->m_super, VFS_I(ip))) {
kmem_cache_free(xfs_inode_cache, ip);
return NULL;
}
/* VFS doesn't initialise i_mode or i_state! */
VFS_I(ip)->i_mode = 0;
VFS_I(ip)->i_state = 0;
mapping_set_large_folios(VFS_I(ip)->i_mapping);
XFS_STATS_INC(mp, vn_active);
ASSERT(atomic_read(&ip->i_pincount) == 0);
ASSERT(ip->i_ino == 0);
/* initialise the xfs inode */
ip->i_ino = ino;
ip->i_mount = mp;
memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
ip->i_cowfp = NULL;
memset(&ip->i_af, 0, sizeof(ip->i_af));
ip->i_af.if_format = XFS_DINODE_FMT_EXTENTS;
memset(&ip->i_df, 0, sizeof(ip->i_df));
ip->i_flags = 0;
ip->i_delayed_blks = 0;
ip->i_diflags2 = mp->m_ino_geo.new_diflags2;
ip->i_nblocks = 0;
ip->i_forkoff = 0;
ip->i_sick = 0;
ip->i_checked = 0;
INIT_WORK(&ip->i_ioend_work, xfs_end_io);
INIT_LIST_HEAD(&ip->i_ioend_list);
spin_lock_init(&ip->i_ioend_lock);
ip->i_next_unlinked = NULLAGINO;
ip->i_prev_unlinked = 0;
return ip;
}
STATIC void
xfs_inode_free_callback(
struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
struct xfs_inode *ip = XFS_I(inode);
switch (VFS_I(ip)->i_mode & S_IFMT) {
case S_IFREG:
case S_IFDIR:
case S_IFLNK:
xfs_idestroy_fork(&ip->i_df);
break;
}
xfs_ifork_zap_attr(ip);
if (ip->i_cowfp) {
xfs_idestroy_fork(ip->i_cowfp);
kmem_cache_free(xfs_ifork_cache, ip->i_cowfp);
}
if (ip->i_itemp) {
ASSERT(!test_bit(XFS_LI_IN_AIL,
&ip->i_itemp->ili_item.li_flags));
xfs_inode_item_destroy(ip);
ip->i_itemp = NULL;
}
kmem_cache_free(xfs_inode_cache, ip);
}
static void
__xfs_inode_free(
struct xfs_inode *ip)
{
/* asserts to verify all state is correct here */
ASSERT(atomic_read(&ip->i_pincount) == 0);
ASSERT(!ip->i_itemp || list_empty(&ip->i_itemp->ili_item.li_bio_list));
XFS_STATS_DEC(ip->i_mount, vn_active);
call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
}
void
xfs_inode_free(
struct xfs_inode *ip)
{
ASSERT(!xfs_iflags_test(ip, XFS_IFLUSHING));
/*
* Because we use RCU freeing we need to ensure the inode always
* appears to be reclaimed with an invalid inode number when in the
* free state. The ip->i_flags_lock provides the barrier against lookup
* races.
*/
spin_lock(&ip->i_flags_lock);
ip->i_flags = XFS_IRECLAIM;
ip->i_ino = 0;
spin_unlock(&ip->i_flags_lock);
__xfs_inode_free(ip);
}
/*
* Queue background inode reclaim work if there are reclaimable inodes and there
* isn't reclaim work already scheduled or in progress.
*/
static void
xfs_reclaim_work_queue(
struct xfs_mount *mp)
{
rcu_read_lock();
if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
queue_delayed_work(mp->m_reclaim_workqueue, &mp->m_reclaim_work,
msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10));
}
rcu_read_unlock();
}
/*
* Background scanning to trim preallocated space. This is queued based on the
* 'speculative_prealloc_lifetime' tunable (5m by default).
*/
static inline void
xfs_blockgc_queue(
struct xfs_perag *pag)
{
struct xfs_mount *mp = pag->pag_mount;
if (!xfs_is_blockgc_enabled(mp))
return;
rcu_read_lock();
if (radix_tree_tagged(&pag->pag_ici_root, XFS_ICI_BLOCKGC_TAG))
queue_delayed_work(pag->pag_mount->m_blockgc_wq,
&pag->pag_blockgc_work,
msecs_to_jiffies(xfs_blockgc_secs * 1000));
rcu_read_unlock();
}
/* Set a tag on both the AG incore inode tree and the AG radix tree. */
static void
xfs_perag_set_inode_tag(
struct xfs_perag *pag,
xfs_agino_t agino,
unsigned int tag)
{
struct xfs_mount *mp = pag->pag_mount;
bool was_tagged;
lockdep_assert_held(&pag->pag_ici_lock);
was_tagged = radix_tree_tagged(&pag->pag_ici_root, tag);
radix_tree_tag_set(&pag->pag_ici_root, agino, tag);
if (tag == XFS_ICI_RECLAIM_TAG)
pag->pag_ici_reclaimable++;
if (was_tagged)
return;
/* propagate the tag up into the perag radix tree */
spin_lock(&mp->m_perag_lock);
radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno, tag);
spin_unlock(&mp->m_perag_lock);
/* start background work */
switch (tag) {
case XFS_ICI_RECLAIM_TAG:
xfs_reclaim_work_queue(mp);
break;
case XFS_ICI_BLOCKGC_TAG:
xfs_blockgc_queue(pag);
break;
}
trace_xfs_perag_set_inode_tag(pag, _RET_IP_);
}
/* Clear a tag on both the AG incore inode tree and the AG radix tree. */
static void
xfs_perag_clear_inode_tag(
struct xfs_perag *pag,
xfs_agino_t agino,
unsigned int tag)
{
struct xfs_mount *mp = pag->pag_mount;
lockdep_assert_held(&pag->pag_ici_lock);
/*
* Reclaim can signal (with a null agino) that it cleared its own tag
* by removing the inode from the radix tree.
*/
if (agino != NULLAGINO)
radix_tree_tag_clear(&pag->pag_ici_root, agino, tag);
else
ASSERT(tag == XFS_ICI_RECLAIM_TAG);
if (tag == XFS_ICI_RECLAIM_TAG)
pag->pag_ici_reclaimable--;
if (radix_tree_tagged(&pag->pag_ici_root, tag))
return;
/* clear the tag from the perag radix tree */
spin_lock(&mp->m_perag_lock);
radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno, tag);
spin_unlock(&mp->m_perag_lock);
trace_xfs_perag_clear_inode_tag(pag, _RET_IP_);
}
/*
* When we recycle a reclaimable inode, we need to re-initialise the VFS inode
* part of the structure. This is made more complex by the fact we store
* information about the on-disk values in the VFS inode and so we can't just
* overwrite the values unconditionally. Hence we save the parameters we
* need to retain across reinitialisation, and rewrite them into the VFS inode
* after reinitialisation even if it fails.
*/
static int
xfs_reinit_inode(
struct xfs_mount *mp,
struct inode *inode)
{
int error;
uint32_t nlink = inode->i_nlink;
uint32_t generation = inode->i_generation;
uint64_t version = inode_peek_iversion(inode);
umode_t mode = inode->i_mode;
dev_t dev = inode->i_rdev;
kuid_t uid = inode->i_uid;
kgid_t gid = inode->i_gid;
error = inode_init_always(mp->m_super, inode);
set_nlink(inode, nlink);
inode->i_generation = generation;
inode_set_iversion_queried(inode, version);
inode->i_mode = mode;
inode->i_rdev = dev;
inode->i_uid = uid;
inode->i_gid = gid;
mapping_set_large_folios(inode->i_mapping);
return error;
}
/*
* Carefully nudge an inode whose VFS state has been torn down back into a
* usable state. Drops the i_flags_lock and the rcu read lock.
*/
static int
xfs_iget_recycle(
struct xfs_perag *pag,
struct xfs_inode *ip) __releases(&ip->i_flags_lock)
{
struct xfs_mount *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);
int error;
trace_xfs_iget_recycle(ip);
if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
return -EAGAIN;
/*
* We need to make it look like the inode is being reclaimed to prevent
* the actual reclaim workers from stomping over us while we recycle
* the inode. We can't clear the radix tree tag yet as it requires
* pag_ici_lock to be held exclusive.
*/
ip->i_flags |= XFS_IRECLAIM;
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
ASSERT(!rwsem_is_locked(&inode->i_rwsem));
error = xfs_reinit_inode(mp, inode);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
if (error) {
/*
* Re-initializing the inode failed, and we are in deep
* trouble. Try to re-add it to the reclaim list.
*/
rcu_read_lock();
spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
trace_xfs_iget_recycle_fail(ip);
return error;
}
spin_lock(&pag->pag_ici_lock);
spin_lock(&ip->i_flags_lock);
/*
* Clear the per-lifetime state in the inode as we are now effectively
* a new inode and need to return to the initial state before reuse
* occurs.
*/
ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
ip->i_flags |= XFS_INEW;
xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
XFS_ICI_RECLAIM_TAG);
inode->i_state = I_NEW;
spin_unlock(&ip->i_flags_lock);
spin_unlock(&pag->pag_ici_lock);
return 0;
}
/*
* If we are allocating a new inode, then check what was returned is
* actually a free, empty inode. If we are not allocating an inode,
* then check we didn't find a free inode.
*
* Returns:
* 0 if the inode free state matches the lookup context
* -ENOENT if the inode is free and we are not allocating
* -EFSCORRUPTED if there is any state mismatch at all
*/
static int
xfs_iget_check_free_state(
struct xfs_inode *ip,
int flags)
{
if (flags & XFS_IGET_CREATE) {
/* should be a free inode */
if (VFS_I(ip)->i_mode != 0) {
xfs_warn(ip->i_mount,
"Corruption detected! Free inode 0x%llx not marked free! (mode 0x%x)",
ip->i_ino, VFS_I(ip)->i_mode);
return -EFSCORRUPTED;
}
if (ip->i_nblocks != 0) {
xfs_warn(ip->i_mount,
"Corruption detected! Free inode 0x%llx has blocks allocated!",
ip->i_ino);
return -EFSCORRUPTED;
}
return 0;
}
/* should be an allocated inode */
if (VFS_I(ip)->i_mode == 0)
return -ENOENT;
return 0;
}
/* Make all pending inactivation work start immediately. */
static bool
xfs_inodegc_queue_all(
struct xfs_mount *mp)
{
struct xfs_inodegc *gc;
int cpu;
bool ret = false;
for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
gc = per_cpu_ptr(mp->m_inodegc, cpu);
if (!llist_empty(&gc->list)) {
mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
ret = true;
}
}
return ret;
}
/* Wait for all queued work and collect errors */
static int
xfs_inodegc_wait_all(
struct xfs_mount *mp)
{
int cpu;
int error = 0;
flush_workqueue(mp->m_inodegc_wq);
for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
struct xfs_inodegc *gc;
gc = per_cpu_ptr(mp->m_inodegc, cpu);
if (gc->error && !error)
error = gc->error;
gc->error = 0;
}
return error;
}
/*
* Check the validity of the inode we just found it the cache
*/
static int
xfs_iget_cache_hit(
struct xfs_perag *pag,
struct xfs_inode *ip,
xfs_ino_t ino,
int flags,
int lock_flags) __releases(RCU)
{
struct inode *inode = VFS_I(ip);
struct xfs_mount *mp = ip->i_mount;
int error;
/*
* check for re-use of an inode within an RCU grace period due to the
* radix tree nodes not being updated yet. We monitor for this by
* setting the inode number to zero before freeing the inode structure.
* If the inode has been reallocated and set up, then the inode number
* will not match, so check for that, too.
*/
spin_lock(&ip->i_flags_lock);
if (ip->i_ino != ino)
goto out_skip;
/*
* If we are racing with another cache hit that is currently
* instantiating this inode or currently recycling it out of
* reclaimable state, wait for the initialisation to complete
* before continuing.
*
* If we're racing with the inactivation worker we also want to wait.
* If we're creating a new file, it's possible that the worker
* previously marked the inode as free on disk but hasn't finished
* updating the incore state yet. The AGI buffer will be dirty and
* locked to the icreate transaction, so a synchronous push of the
* inodegc workers would result in deadlock. For a regular iget, the
* worker is running already, so we might as well wait.
*
* XXX(hch): eventually we should do something equivalent to
* wait_on_inode to wait for these flags to be cleared
* instead of polling for it.
*/
if (ip->i_flags & (XFS_INEW | XFS_IRECLAIM | XFS_INACTIVATING))
goto out_skip;
if (ip->i_flags & XFS_NEED_INACTIVE) {
/* Unlinked inodes cannot be re-grabbed. */
if (VFS_I(ip)->i_nlink == 0) {
error = -ENOENT;
goto out_error;
}
goto out_inodegc_flush;
}
/*
* Check the inode free state is valid. This also detects lookup
* racing with unlinks.
*/
error = xfs_iget_check_free_state(ip, flags);
if (error)
goto out_error;
/* Skip inodes that have no vfs state. */
if ((flags & XFS_IGET_INCORE) &&
(ip->i_flags & XFS_IRECLAIMABLE))
goto out_skip;
/* The inode fits the selection criteria; process it. */
if (ip->i_flags & XFS_IRECLAIMABLE) {
/* Drops i_flags_lock and RCU read lock. */
error = xfs_iget_recycle(pag, ip);
if (error == -EAGAIN)
goto out_skip;
if (error)
return error;
} else {
/* If the VFS inode is being torn down, pause and try again. */
if (!igrab(inode))
goto out_skip;
/* We've got a live one. */
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
trace_xfs_iget_hit(ip);
}
if (lock_flags != 0)
xfs_ilock(ip, lock_flags);
if (!(flags & XFS_IGET_INCORE))
xfs_iflags_clear(ip, XFS_ISTALE);
XFS_STATS_INC(mp, xs_ig_found);
return 0;
out_skip:
trace_xfs_iget_skip(ip);
XFS_STATS_INC(mp, xs_ig_frecycle);
error = -EAGAIN;
out_error:
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
return error;
out_inodegc_flush:
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
/*
* Do not wait for the workers, because the caller could hold an AGI
* buffer lock. We're just going to sleep in a loop anyway.
*/
if (xfs_is_inodegc_enabled(mp))
xfs_inodegc_queue_all(mp);
return -EAGAIN;
}
static int
xfs_iget_cache_miss(
struct xfs_mount *mp,
struct xfs_perag *pag,
xfs_trans_t *tp,
xfs_ino_t ino,
struct xfs_inode **ipp,
int flags,
int lock_flags)
{
struct xfs_inode *ip;
int error;
xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino);
int iflags;
ip = xfs_inode_alloc(mp, ino);
if (!ip)
return -ENOMEM;
error = xfs_imap(pag, tp, ip->i_ino, &ip->i_imap, flags);
if (error)
goto out_destroy;
/*
* For version 5 superblocks, if we are initialising a new inode and we
* are not utilising the XFS_FEAT_IKEEP inode cluster mode, we can
* simply build the new inode core with a random generation number.
*
* For version 4 (and older) superblocks, log recovery is dependent on
* the i_flushiter field being initialised from the current on-disk
* value and hence we must also read the inode off disk even when
* initializing new inodes.
*/
if (xfs_has_v3inodes(mp) &&
(flags & XFS_IGET_CREATE) && !xfs_has_ikeep(mp)) {
VFS_I(ip)->i_generation = get_random_u32();
} else {
struct xfs_buf *bp;
error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &bp);
if (error)
goto out_destroy;
error = xfs_inode_from_disk(ip,
xfs_buf_offset(bp, ip->i_imap.im_boffset));
if (!error)
xfs_buf_set_ref(bp, XFS_INO_REF);
xfs_trans_brelse(tp, bp);
if (error)
goto out_destroy;
}
trace_xfs_iget_miss(ip);
/*
* Check the inode free state is valid. This also detects lookup
* racing with unlinks.
*/
error = xfs_iget_check_free_state(ip, flags);
if (error)
goto out_destroy;
/*
* Preload the radix tree so we can insert safely under the
* write spinlock. Note that we cannot sleep inside the preload
* region. Since we can be called from transaction context, don't
* recurse into the file system.
*/
if (radix_tree_preload(GFP_NOFS)) {
error = -EAGAIN;
goto out_destroy;
}
/*
* Because the inode hasn't been added to the radix-tree yet it can't
* be found by another thread, so we can do the non-sleeping lock here.
*/
if (lock_flags) {
if (!xfs_ilock_nowait(ip, lock_flags))
BUG();
}
/*
* These values must be set before inserting the inode into the radix
* tree as the moment it is inserted a concurrent lookup (allowed by the
* RCU locking mechanism) can find it and that lookup must see that this
* is an inode currently under construction (i.e. that XFS_INEW is set).
* The ip->i_flags_lock that protects the XFS_INEW flag forms the
* memory barrier that ensures this detection works correctly at lookup
* time.
*/
iflags = XFS_INEW;
if (flags & XFS_IGET_DONTCACHE)
d_mark_dontcache(VFS_I(ip));
ip->i_udquot = NULL;
ip->i_gdquot = NULL;
ip->i_pdquot = NULL;
xfs_iflags_set(ip, iflags);
/* insert the new inode */
spin_lock(&pag->pag_ici_lock);
error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
if (unlikely(error)) {
WARN_ON(error != -EEXIST);
XFS_STATS_INC(mp, xs_ig_dup);
error = -EAGAIN;
goto out_preload_end;
}
spin_unlock(&pag->pag_ici_lock);
radix_tree_preload_end();
*ipp = ip;
return 0;
out_preload_end:
spin_unlock(&pag->pag_ici_lock);
radix_tree_preload_end();
if (lock_flags)
xfs_iunlock(ip, lock_flags);
out_destroy:
__destroy_inode(VFS_I(ip));
xfs_inode_free(ip);
return error;
}
/*
* Look up an inode by number in the given file system. The inode is looked up
* in the cache held in each AG. If the inode is found in the cache, initialise
* the vfs inode if necessary.
*
* If it is not in core, read it in from the file system's device, add it to the
* cache and initialise the vfs inode.
*
* The inode is locked according to the value of the lock_flags parameter.
* Inode lookup is only done during metadata operations and not as part of the
* data IO path. Hence we only allow locking of the XFS_ILOCK during lookup.
*/
int
xfs_iget(
struct xfs_mount *mp,
struct xfs_trans *tp,
xfs_ino_t ino,
uint flags,
uint lock_flags,
struct xfs_inode **ipp)
{
struct xfs_inode *ip;
struct xfs_perag *pag;
xfs_agino_t agino;
int error;
ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
/* reject inode numbers outside existing AGs */
if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
return -EINVAL;
XFS_STATS_INC(mp, xs_ig_attempts);
/* get the perag structure and ensure that it's inode capable */
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
agino = XFS_INO_TO_AGINO(mp, ino);
again:
error = 0;
rcu_read_lock();
ip = radix_tree_lookup(&pag->pag_ici_root, agino);
if (ip) {
error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
if (error)
goto out_error_or_again;
} else {
rcu_read_unlock();
if (flags & XFS_IGET_INCORE) {
error = -ENODATA;
goto out_error_or_again;
}
XFS_STATS_INC(mp, xs_ig_missed);
error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
flags, lock_flags);
if (error)
goto out_error_or_again;
}
xfs_perag_put(pag);
*ipp = ip;
/*
* If we have a real type for an on-disk inode, we can setup the inode
* now. If it's a new inode being created, xfs_init_new_inode will
* handle it.
*/
if (xfs_iflags_test(ip, XFS_INEW) && VFS_I(ip)->i_mode != 0)
xfs_setup_existing_inode(ip);
return 0;
out_error_or_again:
if (!(flags & (XFS_IGET_INCORE | XFS_IGET_NORETRY)) &&
error == -EAGAIN) {
delay(1);
goto again;
}
xfs_perag_put(pag);
return error;
}
/*
* Grab the inode for reclaim exclusively.
*
* We have found this inode via a lookup under RCU, so the inode may have
* already been freed, or it may be in the process of being recycled by
* xfs_iget(). In both cases, the inode will have XFS_IRECLAIM set. If the inode
* has been fully recycled by the time we get the i_flags_lock, XFS_IRECLAIMABLE
* will not be set. Hence we need to check for both these flag conditions to
* avoid inodes that are no longer reclaim candidates.
*
* Note: checking for other state flags here, under the i_flags_lock or not, is
* racy and should be avoided. Those races should be resolved only after we have
* ensured that we are able to reclaim this inode and the world can see that we
* are going to reclaim it.
*
* Return true if we grabbed it, false otherwise.
*/
static bool
xfs_reclaim_igrab(
struct xfs_inode *ip,
struct xfs_icwalk *icw)
{
ASSERT(rcu_read_lock_held());
spin_lock(&ip->i_flags_lock);
if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
__xfs_iflags_test(ip, XFS_IRECLAIM)) {
/* not a reclaim candidate. */
spin_unlock(&ip->i_flags_lock);
return false;
}
/* Don't reclaim a sick inode unless the caller asked for it. */
if (ip->i_sick &&
(!icw || !(icw->icw_flags & XFS_ICWALK_FLAG_RECLAIM_SICK))) {
spin_unlock(&ip->i_flags_lock);
return false;
}
__xfs_iflags_set(ip, XFS_IRECLAIM);
spin_unlock(&ip->i_flags_lock);
return true;
}
/*
* Inode reclaim is non-blocking, so the default action if progress cannot be
* made is to "requeue" the inode for reclaim by unlocking it and clearing the
* XFS_IRECLAIM flag. If we are in a shutdown state, we don't care about
* blocking anymore and hence we can wait for the inode to be able to reclaim
* it.
*
* We do no IO here - if callers require inodes to be cleaned they must push the
* AIL first to trigger writeback of dirty inodes. This enables writeback to be
* done in the background in a non-blocking manner, and enables memory reclaim
* to make progress without blocking.
*/
static void
xfs_reclaim_inode(
struct xfs_inode *ip,
struct xfs_perag *pag)
{
xfs_ino_t ino = ip->i_ino; /* for radix_tree_delete */
if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
goto out;
if (xfs_iflags_test_and_set(ip, XFS_IFLUSHING))
goto out_iunlock;
/*
* Check for log shutdown because aborting the inode can move the log
* tail and corrupt in memory state. This is fine if the log is shut
* down, but if the log is still active and only the mount is shut down
* then the in-memory log tail movement caused by the abort can be
* incorrectly propagated to disk.
*/
if (xlog_is_shutdown(ip->i_mount->m_log)) {
xfs_iunpin_wait(ip);
xfs_iflush_shutdown_abort(ip);
goto reclaim;
}
if (xfs_ipincount(ip))
goto out_clear_flush;
if (!xfs_inode_clean(ip))
goto out_clear_flush;
xfs_iflags_clear(ip, XFS_IFLUSHING);
reclaim:
trace_xfs_inode_reclaiming(ip);
/*
* Because we use RCU freeing we need to ensure the inode always appears
* to be reclaimed with an invalid inode number when in the free state.
* We do this as early as possible under the ILOCK so that
* xfs_iflush_cluster() and xfs_ifree_cluster() can be guaranteed to
* detect races with us here. By doing this, we guarantee that once
* xfs_iflush_cluster() or xfs_ifree_cluster() has locked XFS_ILOCK that
* it will see either a valid inode that will serialise correctly, or it
* will see an invalid inode that it can skip.
*/
spin_lock(&ip->i_flags_lock);
ip->i_flags = XFS_IRECLAIM;
ip->i_ino = 0;
ip->i_sick = 0;
ip->i_checked = 0;
spin_unlock(&ip->i_flags_lock);
ASSERT(!ip->i_itemp || ip->i_itemp->ili_item.li_buf == NULL);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
XFS_STATS_INC(ip->i_mount, xs_ig_reclaims);
/*
* Remove the inode from the per-AG radix tree.
*
* Because radix_tree_delete won't complain even if the item was never
* added to the tree assert that it's been there before to catch
* problems with the inode life time early on.
*/
spin_lock(&pag->pag_ici_lock);
if (!radix_tree_delete(&pag->pag_ici_root,
XFS_INO_TO_AGINO(ip->i_mount, ino)))
ASSERT(0);
xfs_perag_clear_inode_tag(pag, NULLAGINO, XFS_ICI_RECLAIM_TAG);
spin_unlock(&pag->pag_ici_lock);
/*
* Here we do an (almost) spurious inode lock in order to coordinate
* with inode cache radix tree lookups. This is because the lookup
* can reference the inodes in the cache without taking references.
*
* We make that OK here by ensuring that we wait until the inode is
* unlocked after the lookup before we go ahead and free it.
*/
xfs_ilock(ip, XFS_ILOCK_EXCL);
ASSERT(!ip->i_udquot && !ip->i_gdquot && !ip->i_pdquot);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
ASSERT(xfs_inode_clean(ip));
__xfs_inode_free(ip);
return;
out_clear_flush:
xfs_iflags_clear(ip, XFS_IFLUSHING);
out_iunlock:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
out:
xfs_iflags_clear(ip, XFS_IRECLAIM);
}
/* Reclaim sick inodes if we're unmounting or the fs went down. */
static inline bool
xfs_want_reclaim_sick(
struct xfs_mount *mp)
{
return xfs_is_unmounting(mp) || xfs_has_norecovery(mp) ||
xfs_is_shutdown(mp);
}
void
xfs_reclaim_inodes(
struct xfs_mount *mp)
{
struct xfs_icwalk icw = {
.icw_flags = 0,
};
if (xfs_want_reclaim_sick(mp))
icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
while (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
xfs_ail_push_all_sync(mp->m_ail);
xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
}
}
/*
* The shrinker infrastructure determines how many inodes we should scan for
* reclaim. We want as many clean inodes ready to reclaim as possible, so we
* push the AIL here. We also want to proactively free up memory if we can to
* minimise the amount of work memory reclaim has to do so we kick the
* background reclaim if it isn't already scheduled.
*/
long
xfs_reclaim_inodes_nr(
struct xfs_mount *mp,
unsigned long nr_to_scan)
{
struct xfs_icwalk icw = {
.icw_flags = XFS_ICWALK_FLAG_SCAN_LIMIT,
.icw_scan_limit = min_t(unsigned long, LONG_MAX, nr_to_scan),
};
if (xfs_want_reclaim_sick(mp))
icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
/* kick background reclaimer and push the AIL */
xfs_reclaim_work_queue(mp);
xfs_ail_push_all(mp->m_ail);
xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
return 0;
}
/*
* Return the number of reclaimable inodes in the filesystem for
* the shrinker to determine how much to reclaim.
*/
long
xfs_reclaim_inodes_count(
struct xfs_mount *mp)
{
struct xfs_perag *pag;
xfs_agnumber_t ag = 0;
long reclaimable = 0;
while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
ag = pag->pag_agno + 1;
reclaimable += pag->pag_ici_reclaimable;
xfs_perag_put(pag);
}
return reclaimable;
}
STATIC bool
xfs_icwalk_match_id(
struct xfs_inode *ip,
struct xfs_icwalk *icw)
{
if ((icw->icw_flags & XFS_ICWALK_FLAG_UID) &&
!uid_eq(VFS_I(ip)->i_uid, icw->icw_uid))
return false;
if ((icw->icw_flags & XFS_ICWALK_FLAG_GID) &&
!gid_eq(VFS_I(ip)->i_gid, icw->icw_gid))
return false;
if ((icw->icw_flags & XFS_ICWALK_FLAG_PRID) &&
ip->i_projid != icw->icw_prid)
return false;
return true;
}
/*
* A union-based inode filtering algorithm. Process the inode if any of the
* criteria match. This is for global/internal scans only.
*/
STATIC bool
xfs_icwalk_match_id_union(
struct xfs_inode *ip,
struct xfs_icwalk *icw)
{
if ((icw->icw_flags & XFS_ICWALK_FLAG_UID) &&
uid_eq(VFS_I(ip)->i_uid, icw->icw_uid))
return true;
if ((icw->icw_flags & XFS_ICWALK_FLAG_GID) &&
gid_eq(VFS_I(ip)->i_gid, icw->icw_gid))
return true;
if ((icw->icw_flags & XFS_ICWALK_FLAG_PRID) &&
ip->i_projid == icw->icw_prid)
return true;
return false;
}
/*
* Is this inode @ip eligible for eof/cow block reclamation, given some
* filtering parameters @icw? The inode is eligible if @icw is null or
* if the predicate functions match.
*/
static bool
xfs_icwalk_match(
struct xfs_inode *ip,
struct xfs_icwalk *icw)
{
bool match;
if (!icw)
return true;
if (icw->icw_flags & XFS_ICWALK_FLAG_UNION)
match = xfs_icwalk_match_id_union(ip, icw);
else
match = xfs_icwalk_match_id(ip, icw);
if (!match)
return false;
/* skip the inode if the file size is too small */
if ((icw->icw_flags & XFS_ICWALK_FLAG_MINFILESIZE) &&
XFS_ISIZE(ip) < icw->icw_min_file_size)
return false;
return true;
}
/*
* This is a fast pass over the inode cache to try to get reclaim moving on as
* many inodes as possible in a short period of time. It kicks itself every few
* seconds, as well as being kicked by the inode cache shrinker when memory
* goes low.
*/
void
xfs_reclaim_worker(
struct work_struct *work)
{
struct xfs_mount *mp = container_of(to_delayed_work(work),
struct xfs_mount, m_reclaim_work);
xfs_icwalk(mp, XFS_ICWALK_RECLAIM, NULL);
xfs_reclaim_work_queue(mp);
}
STATIC int
xfs_inode_free_eofblocks(
struct xfs_inode *ip,
struct xfs_icwalk *icw,
unsigned int *lockflags)
{
bool wait;
wait = icw && (icw->icw_flags & XFS_ICWALK_FLAG_SYNC);
if (!xfs_iflags_test(ip, XFS_IEOFBLOCKS))
return 0;
/*
* If the mapping is dirty the operation can block and wait for some
* time. Unless we are waiting, skip it.
*/
if (!wait && mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY))
return 0;
if (!xfs_icwalk_match(ip, icw))
return 0;
/*
* If the caller is waiting, return -EAGAIN to keep the background
* scanner moving and revisit the inode in a subsequent pass.
*/
if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
if (wait)
return -EAGAIN;
return 0;
}
*lockflags |= XFS_IOLOCK_EXCL;
if (xfs_can_free_eofblocks(ip, false))
return xfs_free_eofblocks(ip);
/* inode could be preallocated or append-only */
trace_xfs_inode_free_eofblocks_invalid(ip);
xfs_inode_clear_eofblocks_tag(ip);
return 0;
}
static void
xfs_blockgc_set_iflag(
struct xfs_inode *ip,
unsigned long iflag)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
ASSERT((iflag & ~(XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0);
/*
* Don't bother locking the AG and looking up in the radix trees
* if we already know that we have the tag set.
*/
if (ip->i_flags & iflag)
return;
spin_lock(&ip->i_flags_lock);
ip->i_flags |= iflag;
spin_unlock(&ip->i_flags_lock);
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
spin_lock(&pag->pag_ici_lock);
xfs_perag_set_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
XFS_ICI_BLOCKGC_TAG);
spin_unlock(&pag->pag_ici_lock);
xfs_perag_put(pag);
}
void
xfs_inode_set_eofblocks_tag(
xfs_inode_t *ip)
{
trace_xfs_inode_set_eofblocks_tag(ip);
return xfs_blockgc_set_iflag(ip, XFS_IEOFBLOCKS);
}
static void
xfs_blockgc_clear_iflag(
struct xfs_inode *ip,
unsigned long iflag)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
bool clear_tag;
ASSERT((iflag & ~(XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0);
spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~iflag;
clear_tag = (ip->i_flags & (XFS_IEOFBLOCKS | XFS_ICOWBLOCKS)) == 0;
spin_unlock(&ip->i_flags_lock);
if (!clear_tag)
return;
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
spin_lock(&pag->pag_ici_lock);
xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
XFS_ICI_BLOCKGC_TAG);
spin_unlock(&pag->pag_ici_lock);
xfs_perag_put(pag);
}
void
xfs_inode_clear_eofblocks_tag(
xfs_inode_t *ip)
{
trace_xfs_inode_clear_eofblocks_tag(ip);
return xfs_blockgc_clear_iflag(ip, XFS_IEOFBLOCKS);
}
/*
* Set ourselves up to free CoW blocks from this file. If it's already clean
* then we can bail out quickly, but otherwise we must back off if the file
* is undergoing some kind of write.
*/
static bool
xfs_prep_free_cowblocks(
struct xfs_inode *ip)
{
/*
* Just clear the tag if we have an empty cow fork or none at all. It's
* possible the inode was fully unshared since it was originally tagged.
*/
if (!xfs_inode_has_cow_data(ip)) {
trace_xfs_inode_free_cowblocks_invalid(ip);
xfs_inode_clear_cowblocks_tag(ip);
return false;
}
/*
* If the mapping is dirty or under writeback we cannot touch the
* CoW fork. Leave it alone if we're in the midst of a directio.
*/
if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) ||
mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) ||
mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) ||
atomic_read(&VFS_I(ip)->i_dio_count))
return false;
return true;
}
/*
* Automatic CoW Reservation Freeing
*
* These functions automatically garbage collect leftover CoW reservations
* that were made on behalf of a cowextsize hint when we start to run out
* of quota or when the reservations sit around for too long. If the file
* has dirty pages or is undergoing writeback, its CoW reservations will
* be retained.
*
* The actual garbage collection piggybacks off the same code that runs
* the speculative EOF preallocation garbage collector.
*/
STATIC int
xfs_inode_free_cowblocks(
struct xfs_inode *ip,
struct xfs_icwalk *icw,
unsigned int *lockflags)
{
bool wait;
int ret = 0;
wait = icw && (icw->icw_flags & XFS_ICWALK_FLAG_SYNC);
if (!xfs_iflags_test(ip, XFS_ICOWBLOCKS))
return 0;
if (!xfs_prep_free_cowblocks(ip))
return 0;
if (!xfs_icwalk_match(ip, icw))
return 0;
/*
* If the caller is waiting, return -EAGAIN to keep the background
* scanner moving and revisit the inode in a subsequent pass.
*/
if (!(*lockflags & XFS_IOLOCK_EXCL) &&
!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
if (wait)
return -EAGAIN;
return 0;
}
*lockflags |= XFS_IOLOCK_EXCL;
if (!xfs_ilock_nowait(ip, XFS_MMAPLOCK_EXCL)) {
if (wait)
return -EAGAIN;
return 0;
}
*lockflags |= XFS_MMAPLOCK_EXCL;
/*
* Check again, nobody else should be able to dirty blocks or change
* the reflink iflag now that we have the first two locks held.
*/
if (xfs_prep_free_cowblocks(ip))
ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false);
return ret;
}
void
xfs_inode_set_cowblocks_tag(
xfs_inode_t *ip)
{
trace_xfs_inode_set_cowblocks_tag(ip);
return xfs_blockgc_set_iflag(ip, XFS_ICOWBLOCKS);
}
void
xfs_inode_clear_cowblocks_tag(
xfs_inode_t *ip)
{
trace_xfs_inode_clear_cowblocks_tag(ip);
return xfs_blockgc_clear_iflag(ip, XFS_ICOWBLOCKS);
}
/* Disable post-EOF and CoW block auto-reclamation. */
void
xfs_blockgc_stop(
struct xfs_mount *mp)
{
struct xfs_perag *pag;
xfs_agnumber_t agno;
if (!xfs_clear_blockgc_enabled(mp))
return;
for_each_perag(mp, agno, pag)
cancel_delayed_work_sync(&pag->pag_blockgc_work);
trace_xfs_blockgc_stop(mp, __return_address);
}
/* Enable post-EOF and CoW block auto-reclamation. */
void
xfs_blockgc_start(
struct xfs_mount *mp)
{
struct xfs_perag *pag;
xfs_agnumber_t agno;
if (xfs_set_blockgc_enabled(mp))
return;
trace_xfs_blockgc_start(mp, __return_address);
for_each_perag_tag(mp, agno, pag, XFS_ICI_BLOCKGC_TAG)
xfs_blockgc_queue(pag);
}
/* Don't try to run block gc on an inode that's in any of these states. */
#define XFS_BLOCKGC_NOGRAB_IFLAGS (XFS_INEW | \
XFS_NEED_INACTIVE | \
XFS_INACTIVATING | \
XFS_IRECLAIMABLE | \
XFS_IRECLAIM)
/*
* Decide if the given @ip is eligible for garbage collection of speculative
* preallocations, and grab it if so. Returns true if it's ready to go or
* false if we should just ignore it.
*/
static bool
xfs_blockgc_igrab(
struct xfs_inode *ip)
{
struct inode *inode = VFS_I(ip);
ASSERT(rcu_read_lock_held());
/* Check for stale RCU freed inode */
spin_lock(&ip->i_flags_lock);
if (!ip->i_ino)
goto out_unlock_noent;
if (ip->i_flags & XFS_BLOCKGC_NOGRAB_IFLAGS)
goto out_unlock_noent;
spin_unlock(&ip->i_flags_lock);
/* nothing to sync during shutdown */
if (xfs_is_shutdown(ip->i_mount))
return false;
/* If we can't grab the inode, it must on it's way to reclaim. */
if (!igrab(inode))
return false;
/* inode is valid */
return true;
out_unlock_noent:
spin_unlock(&ip->i_flags_lock);
return false;
}
/* Scan one incore inode for block preallocations that we can remove. */
static int
xfs_blockgc_scan_inode(
struct xfs_inode *ip,
struct xfs_icwalk *icw)
{
unsigned int lockflags = 0;
int error;
error = xfs_inode_free_eofblocks(ip, icw, &lockflags);
if (error)
goto unlock;
error = xfs_inode_free_cowblocks(ip, icw, &lockflags);
unlock:
if (lockflags)
xfs_iunlock(ip, lockflags);
xfs_irele(ip);
return error;
}
/* Background worker that trims preallocated space. */
void
xfs_blockgc_worker(
struct work_struct *work)
{
struct xfs_perag *pag = container_of(to_delayed_work(work),
struct xfs_perag, pag_blockgc_work);
struct xfs_mount *mp = pag->pag_mount;
int error;
trace_xfs_blockgc_worker(mp, __return_address);
error = xfs_icwalk_ag(pag, XFS_ICWALK_BLOCKGC, NULL);
if (error)
xfs_info(mp, "AG %u preallocation gc worker failed, err=%d",
pag->pag_agno, error);
xfs_blockgc_queue(pag);
}
/*
* Try to free space in the filesystem by purging inactive inodes, eofblocks
* and cowblocks.
*/
int
xfs_blockgc_free_space(
struct xfs_mount *mp,
struct xfs_icwalk *icw)
{
int error;
trace_xfs_blockgc_free_space(mp, icw, _RET_IP_);
error = xfs_icwalk(mp, XFS_ICWALK_BLOCKGC, icw);
if (error)
return error;
return xfs_inodegc_flush(mp);
}
/*
* Reclaim all the free space that we can by scheduling the background blockgc
* and inodegc workers immediately and waiting for them all to clear.
*/
int
xfs_blockgc_flush_all(
struct xfs_mount *mp)
{
struct xfs_perag *pag;
xfs_agnumber_t agno;
trace_xfs_blockgc_flush_all(mp, __return_address);
/*
* For each blockgc worker, move its queue time up to now. If it
* wasn't queued, it will not be requeued. Then flush whatever's
* left.
*/
for_each_perag_tag(mp, agno, pag, XFS_ICI_BLOCKGC_TAG)
mod_delayed_work(pag->pag_mount->m_blockgc_wq,
&pag->pag_blockgc_work, 0);
for_each_perag_tag(mp, agno, pag, XFS_ICI_BLOCKGC_TAG)
flush_delayed_work(&pag->pag_blockgc_work);
return xfs_inodegc_flush(mp);
}
/*
* Run cow/eofblocks scans on the supplied dquots. We don't know exactly which
* quota caused an allocation failure, so we make a best effort by including
* each quota under low free space conditions (less than 1% free space) in the
* scan.
*
* Callers must not hold any inode's ILOCK. If requesting a synchronous scan
* (XFS_ICWALK_FLAG_SYNC), the caller also must not hold any inode's IOLOCK or
* MMAPLOCK.
*/
int
xfs_blockgc_free_dquots(
struct xfs_mount *mp,
struct xfs_dquot *udqp,
struct xfs_dquot *gdqp,
struct xfs_dquot *pdqp,
unsigned int iwalk_flags)
{
struct xfs_icwalk icw = {0};
bool do_work = false;
if (!udqp && !gdqp && !pdqp)
return 0;
/*
* Run a scan to free blocks using the union filter to cover all
* applicable quotas in a single scan.
*/
icw.icw_flags = XFS_ICWALK_FLAG_UNION | iwalk_flags;
if (XFS_IS_UQUOTA_ENFORCED(mp) && udqp && xfs_dquot_lowsp(udqp)) {
icw.icw_uid = make_kuid(mp->m_super->s_user_ns, udqp->q_id);
icw.icw_flags |= XFS_ICWALK_FLAG_UID;
do_work = true;
}
if (XFS_IS_UQUOTA_ENFORCED(mp) && gdqp && xfs_dquot_lowsp(gdqp)) {
icw.icw_gid = make_kgid(mp->m_super->s_user_ns, gdqp->q_id);
icw.icw_flags |= XFS_ICWALK_FLAG_GID;
do_work = true;
}
if (XFS_IS_PQUOTA_ENFORCED(mp) && pdqp && xfs_dquot_lowsp(pdqp)) {
icw.icw_prid = pdqp->q_id;
icw.icw_flags |= XFS_ICWALK_FLAG_PRID;
do_work = true;
}
if (!do_work)
return 0;
return xfs_blockgc_free_space(mp, &icw);
}
/* Run cow/eofblocks scans on the quotas attached to the inode. */
int
xfs_blockgc_free_quota(
struct xfs_inode *ip,
unsigned int iwalk_flags)
{
return xfs_blockgc_free_dquots(ip->i_mount,
xfs_inode_dquot(ip, XFS_DQTYPE_USER),
xfs_inode_dquot(ip, XFS_DQTYPE_GROUP),
xfs_inode_dquot(ip, XFS_DQTYPE_PROJ), iwalk_flags);
}
/* XFS Inode Cache Walking Code */
/*
* The inode lookup is done in batches to keep the amount of lock traffic and
* radix tree lookups to a minimum. The batch size is a trade off between
* lookup reduction and stack usage. This is in the reclaim path, so we can't
* be too greedy.
*/
#define XFS_LOOKUP_BATCH 32
/*
* Decide if we want to grab this inode in anticipation of doing work towards
* the goal.
*/
static inline bool
xfs_icwalk_igrab(
enum xfs_icwalk_goal goal,
struct xfs_inode *ip,
struct xfs_icwalk *icw)
{
switch (goal) {
case XFS_ICWALK_BLOCKGC:
return xfs_blockgc_igrab(ip);
case XFS_ICWALK_RECLAIM:
return xfs_reclaim_igrab(ip, icw);
default:
return false;
}
}
/*
* Process an inode. Each processing function must handle any state changes
* made by the icwalk igrab function. Return -EAGAIN to skip an inode.
*/
static inline int
xfs_icwalk_process_inode(
enum xfs_icwalk_goal goal,
struct xfs_inode *ip,
struct xfs_perag *pag,
struct xfs_icwalk *icw)
{
int error = 0;
switch (goal) {
case XFS_ICWALK_BLOCKGC:
error = xfs_blockgc_scan_inode(ip, icw);
break;
case XFS_ICWALK_RECLAIM:
xfs_reclaim_inode(ip, pag);
break;
}
return error;
}
/*
* For a given per-AG structure @pag and a goal, grab qualifying inodes and
* process them in some manner.
*/
static int
xfs_icwalk_ag(
struct xfs_perag *pag,
enum xfs_icwalk_goal goal,
struct xfs_icwalk *icw)
{
struct xfs_mount *mp = pag->pag_mount;
uint32_t first_index;
int last_error = 0;
int skipped;
bool done;
int nr_found;
restart:
done = false;
skipped = 0;
if (goal == XFS_ICWALK_RECLAIM)
first_index = READ_ONCE(pag->pag_ici_reclaim_cursor);
else
first_index = 0;
nr_found = 0;
do {
struct xfs_inode *batch[XFS_LOOKUP_BATCH];
int error = 0;
int i;
rcu_read_lock();
nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
(void **) batch, first_index,
XFS_LOOKUP_BATCH, goal);
if (!nr_found) {
done = true;
rcu_read_unlock();
break;
}
/*
* Grab the inodes before we drop the lock. if we found
* nothing, nr == 0 and the loop will be skipped.
*/
for (i = 0; i < nr_found; i++) {
struct xfs_inode *ip = batch[i];
if (done || !xfs_icwalk_igrab(goal, ip, icw))
batch[i] = NULL;
/*
* Update the index for the next lookup. Catch
* overflows into the next AG range which can occur if
* we have inodes in the last block of the AG and we
* are currently pointing to the last inode.
*
* Because we may see inodes that are from the wrong AG
* due to RCU freeing and reallocation, only update the
* index if it lies in this AG. It was a race that lead
* us to see this inode, so another lookup from the
* same index will not find it again.
*/
if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno)
continue;
first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
done = true;
}
/* unlock now we've grabbed the inodes. */
rcu_read_unlock();
for (i = 0; i < nr_found; i++) {
if (!batch[i])
continue;
error = xfs_icwalk_process_inode(goal, batch[i], pag,
icw);
if (error == -EAGAIN) {
skipped++;
continue;
}
if (error && last_error != -EFSCORRUPTED)
last_error = error;
}
/* bail out if the filesystem is corrupted. */
if (error == -EFSCORRUPTED)
break;
cond_resched();
if (icw && (icw->icw_flags & XFS_ICWALK_FLAG_SCAN_LIMIT)) {
icw->icw_scan_limit -= XFS_LOOKUP_BATCH;
if (icw->icw_scan_limit <= 0)
break;
}
} while (nr_found && !done);
if (goal == XFS_ICWALK_RECLAIM) {
if (done)
first_index = 0;
WRITE_ONCE(pag->pag_ici_reclaim_cursor, first_index);
}
if (skipped) {
delay(1);
goto restart;
}
return last_error;
}
/* Walk all incore inodes to achieve a given goal. */
static int
xfs_icwalk(
struct xfs_mount *mp,
enum xfs_icwalk_goal goal,
struct xfs_icwalk *icw)
{
struct xfs_perag *pag;
int error = 0;
int last_error = 0;
xfs_agnumber_t agno;
for_each_perag_tag(mp, agno, pag, goal) {
error = xfs_icwalk_ag(pag, goal, icw);
if (error) {
last_error = error;
if (error == -EFSCORRUPTED) {
xfs_perag_rele(pag);
break;
}
}
}
return last_error;
BUILD_BUG_ON(XFS_ICWALK_PRIVATE_FLAGS & XFS_ICWALK_FLAGS_VALID);
}
#ifdef DEBUG
static void
xfs_check_delalloc(
struct xfs_inode *ip,
int whichfork)
{
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
struct xfs_bmbt_irec got;
struct xfs_iext_cursor icur;
if (!ifp || !xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got))
return;
do {
if (isnullstartblock(got.br_startblock)) {
xfs_warn(ip->i_mount,
"ino %llx %s fork has delalloc extent at [0x%llx:0x%llx]",
ip->i_ino,
whichfork == XFS_DATA_FORK ? "data" : "cow",
got.br_startoff, got.br_blockcount);
}
} while (xfs_iext_next_extent(ifp, &icur, &got));
}
#else
#define xfs_check_delalloc(ip, whichfork) do { } while (0)
#endif
/* Schedule the inode for reclaim. */
static void
xfs_inodegc_set_reclaimable(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
if (!xfs_is_shutdown(mp) && ip->i_delayed_blks) {
xfs_check_delalloc(ip, XFS_DATA_FORK);
xfs_check_delalloc(ip, XFS_COW_FORK);
ASSERT(0);
}
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
spin_lock(&pag->pag_ici_lock);
spin_lock(&ip->i_flags_lock);
trace_xfs_inode_set_reclaimable(ip);
ip->i_flags &= ~(XFS_NEED_INACTIVE | XFS_INACTIVATING);
ip->i_flags |= XFS_IRECLAIMABLE;
xfs_perag_set_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
XFS_ICI_RECLAIM_TAG);
spin_unlock(&ip->i_flags_lock);
spin_unlock(&pag->pag_ici_lock);
xfs_perag_put(pag);
}
/*
* Free all speculative preallocations and possibly even the inode itself.
* This is the last chance to make changes to an otherwise unreferenced file
* before incore reclamation happens.
*/
static int
xfs_inodegc_inactivate(
struct xfs_inode *ip)
{
int error;
trace_xfs_inode_inactivating(ip);
error = xfs_inactive(ip);
xfs_inodegc_set_reclaimable(ip);
return error;
}
void
xfs_inodegc_worker(
struct work_struct *work)
{
struct xfs_inodegc *gc = container_of(to_delayed_work(work),
struct xfs_inodegc, work);
struct llist_node *node = llist_del_all(&gc->list);
struct xfs_inode *ip, *n;
struct xfs_mount *mp = gc->mp;
unsigned int nofs_flag;
/*
* Clear the cpu mask bit and ensure that we have seen the latest
* update of the gc structure associated with this CPU. This matches
* with the release semantics used when setting the cpumask bit in
* xfs_inodegc_queue.
*/
cpumask_clear_cpu(gc->cpu, &mp->m_inodegc_cpumask);
smp_mb__after_atomic();
WRITE_ONCE(gc->items, 0);
if (!node)
return;
/*
* We can allocate memory here while doing writeback on behalf of
* memory reclaim. To avoid memory allocation deadlocks set the
* task-wide nofs context for the following operations.
*/
nofs_flag = memalloc_nofs_save();
ip = llist_entry(node, struct xfs_inode, i_gclist);
trace_xfs_inodegc_worker(mp, READ_ONCE(gc->shrinker_hits));
WRITE_ONCE(gc->shrinker_hits, 0);
llist_for_each_entry_safe(ip, n, node, i_gclist) {
int error;
xfs_iflags_set(ip, XFS_INACTIVATING);
error = xfs_inodegc_inactivate(ip);
if (error && !gc->error)
gc->error = error;
}
memalloc_nofs_restore(nofs_flag);
}
/*
* Expedite all pending inodegc work to run immediately. This does not wait for
* completion of the work.
*/
void
xfs_inodegc_push(
struct xfs_mount *mp)
{
if (!xfs_is_inodegc_enabled(mp))
return;
trace_xfs_inodegc_push(mp, __return_address);
xfs_inodegc_queue_all(mp);
}
/*
* Force all currently queued inode inactivation work to run immediately and
* wait for the work to finish.
*/
int
xfs_inodegc_flush(
struct xfs_mount *mp)
{
xfs_inodegc_push(mp);
trace_xfs_inodegc_flush(mp, __return_address);
return xfs_inodegc_wait_all(mp);
}
/*
* Flush all the pending work and then disable the inode inactivation background
* workers and wait for them to stop. Caller must hold sb->s_umount to
* coordinate changes in the inodegc_enabled state.
*/
void
xfs_inodegc_stop(
struct xfs_mount *mp)
{
bool rerun;
if (!xfs_clear_inodegc_enabled(mp))
return;
/*
* Drain all pending inodegc work, including inodes that could be
* queued by racing xfs_inodegc_queue or xfs_inodegc_shrinker_scan
* threads that sample the inodegc state just prior to us clearing it.
* The inodegc flag state prevents new threads from queuing more
* inodes, so we queue pending work items and flush the workqueue until
* all inodegc lists are empty. IOWs, we cannot use drain_workqueue
* here because it does not allow other unserialized mechanisms to
* reschedule inodegc work while this draining is in progress.
*/
xfs_inodegc_queue_all(mp);
do {
flush_workqueue(mp->m_inodegc_wq);
rerun = xfs_inodegc_queue_all(mp);
} while (rerun);
trace_xfs_inodegc_stop(mp, __return_address);
}
/*
* Enable the inode inactivation background workers and schedule deferred inode
* inactivation work if there is any. Caller must hold sb->s_umount to
* coordinate changes in the inodegc_enabled state.
*/
void
xfs_inodegc_start(
struct xfs_mount *mp)
{
if (xfs_set_inodegc_enabled(mp))
return;
trace_xfs_inodegc_start(mp, __return_address);
xfs_inodegc_queue_all(mp);
}
#ifdef CONFIG_XFS_RT
static inline bool
xfs_inodegc_want_queue_rt_file(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
if (!XFS_IS_REALTIME_INODE(ip))
return false;
if (__percpu_counter_compare(&mp->m_frextents,
mp->m_low_rtexts[XFS_LOWSP_5_PCNT],
XFS_FDBLOCKS_BATCH) < 0)
return true;
return false;
}
#else
# define xfs_inodegc_want_queue_rt_file(ip) (false)
#endif /* CONFIG_XFS_RT */
/*
* Schedule the inactivation worker when:
*
* - We've accumulated more than one inode cluster buffer's worth of inodes.
* - There is less than 5% free space left.
* - Any of the quotas for this inode are near an enforcement limit.
*/
static inline bool
xfs_inodegc_want_queue_work(
struct xfs_inode *ip,
unsigned int items)
{
struct xfs_mount *mp = ip->i_mount;
if (items > mp->m_ino_geo.inodes_per_cluster)
return true;
if (__percpu_counter_compare(&mp->m_fdblocks,
mp->m_low_space[XFS_LOWSP_5_PCNT],
XFS_FDBLOCKS_BATCH) < 0)
return true;
if (xfs_inodegc_want_queue_rt_file(ip))
return true;
if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_USER))
return true;
if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_GROUP))
return true;
if (xfs_inode_near_dquot_enforcement(ip, XFS_DQTYPE_PROJ))
return true;
return false;
}
/*
* Upper bound on the number of inodes in each AG that can be queued for
* inactivation at any given time, to avoid monopolizing the workqueue.
*/
#define XFS_INODEGC_MAX_BACKLOG (4 * XFS_INODES_PER_CHUNK)
/*
* Make the frontend wait for inactivations when:
*
* - Memory shrinkers queued the inactivation worker and it hasn't finished.
* - The queue depth exceeds the maximum allowable percpu backlog.
*
* Note: If the current thread is running a transaction, we don't ever want to
* wait for other transactions because that could introduce a deadlock.
*/
static inline bool
xfs_inodegc_want_flush_work(
struct xfs_inode *ip,
unsigned int items,
unsigned int shrinker_hits)
{
if (current->journal_info)
return false;
if (shrinker_hits > 0)
return true;
if (items > XFS_INODEGC_MAX_BACKLOG)
return true;
return false;
}
/*
* Queue a background inactivation worker if there are inodes that need to be
* inactivated and higher level xfs code hasn't disabled the background
* workers.
*/
static void
xfs_inodegc_queue(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_inodegc *gc;
int items;
unsigned int shrinker_hits;
unsigned int cpu_nr;
unsigned long queue_delay = 1;
trace_xfs_inode_set_need_inactive(ip);
spin_lock(&ip->i_flags_lock);
ip->i_flags |= XFS_NEED_INACTIVE;
spin_unlock(&ip->i_flags_lock);
cpu_nr = get_cpu();
gc = this_cpu_ptr(mp->m_inodegc);
llist_add(&ip->i_gclist, &gc->list);
items = READ_ONCE(gc->items);
WRITE_ONCE(gc->items, items + 1);
shrinker_hits = READ_ONCE(gc->shrinker_hits);
/*
* Ensure the list add is always seen by anyone who finds the cpumask
* bit set. This effectively gives the cpumask bit set operation
* release ordering semantics.
*/
smp_mb__before_atomic();
if (!cpumask_test_cpu(cpu_nr, &mp->m_inodegc_cpumask))
cpumask_test_and_set_cpu(cpu_nr, &mp->m_inodegc_cpumask);
/*
* We queue the work while holding the current CPU so that the work
* is scheduled to run on this CPU.
*/
if (!xfs_is_inodegc_enabled(mp)) {
put_cpu();
return;
}
if (xfs_inodegc_want_queue_work(ip, items))
queue_delay = 0;
trace_xfs_inodegc_queue(mp, __return_address);
mod_delayed_work_on(current_cpu(), mp->m_inodegc_wq, &gc->work,
queue_delay);
put_cpu();
if (xfs_inodegc_want_flush_work(ip, items, shrinker_hits)) {
trace_xfs_inodegc_throttle(mp, __return_address);
flush_delayed_work(&gc->work);
}
}
/*
* We set the inode flag atomically with the radix tree tag. Once we get tag
* lookups on the radix tree, this inode flag can go away.
*
* We always use background reclaim here because even if the inode is clean, it
* still may be under IO and hence we have wait for IO completion to occur
* before we can reclaim the inode. The background reclaim path handles this
* more efficiently than we can here, so simply let background reclaim tear down
* all inodes.
*/
void
xfs_inode_mark_reclaimable(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
bool need_inactive;
XFS_STATS_INC(mp, vn_reclaim);
/*
* We should never get here with any of the reclaim flags already set.
*/
ASSERT_ALWAYS(!xfs_iflags_test(ip, XFS_ALL_IRECLAIM_FLAGS));
need_inactive = xfs_inode_needs_inactive(ip);
if (need_inactive) {
xfs_inodegc_queue(ip);
return;
}
/* Going straight to reclaim, so drop the dquots. */
xfs_qm_dqdetach(ip);
xfs_inodegc_set_reclaimable(ip);
}
/*
* Register a phony shrinker so that we can run background inodegc sooner when
* there's memory pressure. Inactivation does not itself free any memory but
* it does make inodes reclaimable, which eventually frees memory.
*
* The count function, seek value, and batch value are crafted to trigger the
* scan function during the second round of scanning. Hopefully this means
* that we reclaimed enough memory that initiating metadata transactions won't
* make things worse.
*/
#define XFS_INODEGC_SHRINKER_COUNT (1UL << DEF_PRIORITY)
#define XFS_INODEGC_SHRINKER_BATCH ((XFS_INODEGC_SHRINKER_COUNT / 2) + 1)
static unsigned long
xfs_inodegc_shrinker_count(
struct shrinker *shrink,
struct shrink_control *sc)
{
struct xfs_mount *mp = container_of(shrink, struct xfs_mount,
m_inodegc_shrinker);
struct xfs_inodegc *gc;
int cpu;
if (!xfs_is_inodegc_enabled(mp))
return 0;
for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
gc = per_cpu_ptr(mp->m_inodegc, cpu);
if (!llist_empty(&gc->list))
return XFS_INODEGC_SHRINKER_COUNT;
}
return 0;
}
static unsigned long
xfs_inodegc_shrinker_scan(
struct shrinker *shrink,
struct shrink_control *sc)
{
struct xfs_mount *mp = container_of(shrink, struct xfs_mount,
m_inodegc_shrinker);
struct xfs_inodegc *gc;
int cpu;
bool no_items = true;
if (!xfs_is_inodegc_enabled(mp))
return SHRINK_STOP;
trace_xfs_inodegc_shrinker_scan(mp, sc, __return_address);
for_each_cpu(cpu, &mp->m_inodegc_cpumask) {
gc = per_cpu_ptr(mp->m_inodegc, cpu);
if (!llist_empty(&gc->list)) {
unsigned int h = READ_ONCE(gc->shrinker_hits);
WRITE_ONCE(gc->shrinker_hits, h + 1);
mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
no_items = false;
}
}
/*
* If there are no inodes to inactivate, we don't want the shrinker
* to think there's deferred work to call us back about.
*/
if (no_items)
return LONG_MAX;
return SHRINK_STOP;
}
/* Register a shrinker so we can accelerate inodegc and throttle queuing. */
int
xfs_inodegc_register_shrinker(
struct xfs_mount *mp)
{
struct shrinker *shrink = &mp->m_inodegc_shrinker;
shrink->count_objects = xfs_inodegc_shrinker_count;
shrink->scan_objects = xfs_inodegc_shrinker_scan;
shrink->seeks = 0;
shrink->flags = SHRINKER_NONSLAB;
shrink->batch = XFS_INODEGC_SHRINKER_BATCH;
return register_shrinker(shrink, "xfs-inodegc:%s", mp->m_super->s_id);
}
| linux-master | fs/xfs/xfs_icache.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_rtalloc.h"
#include "xfs_iwalk.h"
#include "xfs_itable.h"
#include "xfs_error.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_fsops.h"
#include "xfs_discard.h"
#include "xfs_quota.h"
#include "xfs_export.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_trans.h"
#include "xfs_acl.h"
#include "xfs_btree.h"
#include <linux/fsmap.h>
#include "xfs_fsmap.h"
#include "scrub/xfs_scrub.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_health.h"
#include "xfs_reflink.h"
#include "xfs_ioctl.h"
#include "xfs_xattr.h"
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/fileattr.h>
/*
* xfs_find_handle maps from userspace xfs_fsop_handlereq structure to
* a file or fs handle.
*
* XFS_IOC_PATH_TO_FSHANDLE
* returns fs handle for a mount point or path within that mount point
* XFS_IOC_FD_TO_HANDLE
* returns full handle for a FD opened in user space
* XFS_IOC_PATH_TO_HANDLE
* returns full handle for a path
*/
int
xfs_find_handle(
unsigned int cmd,
xfs_fsop_handlereq_t *hreq)
{
int hsize;
xfs_handle_t handle;
struct inode *inode;
struct fd f = {NULL};
struct path path;
int error;
struct xfs_inode *ip;
if (cmd == XFS_IOC_FD_TO_HANDLE) {
f = fdget(hreq->fd);
if (!f.file)
return -EBADF;
inode = file_inode(f.file);
} else {
error = user_path_at(AT_FDCWD, hreq->path, 0, &path);
if (error)
return error;
inode = d_inode(path.dentry);
}
ip = XFS_I(inode);
/*
* We can only generate handles for inodes residing on a XFS filesystem,
* and only for regular files, directories or symbolic links.
*/
error = -EINVAL;
if (inode->i_sb->s_magic != XFS_SB_MAGIC)
goto out_put;
error = -EBADF;
if (!S_ISREG(inode->i_mode) &&
!S_ISDIR(inode->i_mode) &&
!S_ISLNK(inode->i_mode))
goto out_put;
memcpy(&handle.ha_fsid, ip->i_mount->m_fixedfsid, sizeof(xfs_fsid_t));
if (cmd == XFS_IOC_PATH_TO_FSHANDLE) {
/*
* This handle only contains an fsid, zero the rest.
*/
memset(&handle.ha_fid, 0, sizeof(handle.ha_fid));
hsize = sizeof(xfs_fsid_t);
} else {
handle.ha_fid.fid_len = sizeof(xfs_fid_t) -
sizeof(handle.ha_fid.fid_len);
handle.ha_fid.fid_pad = 0;
handle.ha_fid.fid_gen = inode->i_generation;
handle.ha_fid.fid_ino = ip->i_ino;
hsize = sizeof(xfs_handle_t);
}
error = -EFAULT;
if (copy_to_user(hreq->ohandle, &handle, hsize) ||
copy_to_user(hreq->ohandlen, &hsize, sizeof(__s32)))
goto out_put;
error = 0;
out_put:
if (cmd == XFS_IOC_FD_TO_HANDLE)
fdput(f);
else
path_put(&path);
return error;
}
/*
* No need to do permission checks on the various pathname components
* as the handle operations are privileged.
*/
STATIC int
xfs_handle_acceptable(
void *context,
struct dentry *dentry)
{
return 1;
}
/*
* Convert userspace handle data into a dentry.
*/
struct dentry *
xfs_handle_to_dentry(
struct file *parfilp,
void __user *uhandle,
u32 hlen)
{
xfs_handle_t handle;
struct xfs_fid64 fid;
/*
* Only allow handle opens under a directory.
*/
if (!S_ISDIR(file_inode(parfilp)->i_mode))
return ERR_PTR(-ENOTDIR);
if (hlen != sizeof(xfs_handle_t))
return ERR_PTR(-EINVAL);
if (copy_from_user(&handle, uhandle, hlen))
return ERR_PTR(-EFAULT);
if (handle.ha_fid.fid_len !=
sizeof(handle.ha_fid) - sizeof(handle.ha_fid.fid_len))
return ERR_PTR(-EINVAL);
memset(&fid, 0, sizeof(struct fid));
fid.ino = handle.ha_fid.fid_ino;
fid.gen = handle.ha_fid.fid_gen;
return exportfs_decode_fh(parfilp->f_path.mnt, (struct fid *)&fid, 3,
FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG,
xfs_handle_acceptable, NULL);
}
STATIC struct dentry *
xfs_handlereq_to_dentry(
struct file *parfilp,
xfs_fsop_handlereq_t *hreq)
{
return xfs_handle_to_dentry(parfilp, hreq->ihandle, hreq->ihandlen);
}
int
xfs_open_by_handle(
struct file *parfilp,
xfs_fsop_handlereq_t *hreq)
{
const struct cred *cred = current_cred();
int error;
int fd;
int permflag;
struct file *filp;
struct inode *inode;
struct dentry *dentry;
fmode_t fmode;
struct path path;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
dentry = xfs_handlereq_to_dentry(parfilp, hreq);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
inode = d_inode(dentry);
/* Restrict xfs_open_by_handle to directories & regular files. */
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) {
error = -EPERM;
goto out_dput;
}
#if BITS_PER_LONG != 32
hreq->oflags |= O_LARGEFILE;
#endif
permflag = hreq->oflags;
fmode = OPEN_FMODE(permflag);
if ((!(permflag & O_APPEND) || (permflag & O_TRUNC)) &&
(fmode & FMODE_WRITE) && IS_APPEND(inode)) {
error = -EPERM;
goto out_dput;
}
if ((fmode & FMODE_WRITE) && IS_IMMUTABLE(inode)) {
error = -EPERM;
goto out_dput;
}
/* Can't write directories. */
if (S_ISDIR(inode->i_mode) && (fmode & FMODE_WRITE)) {
error = -EISDIR;
goto out_dput;
}
fd = get_unused_fd_flags(0);
if (fd < 0) {
error = fd;
goto out_dput;
}
path.mnt = parfilp->f_path.mnt;
path.dentry = dentry;
filp = dentry_open(&path, hreq->oflags, cred);
dput(dentry);
if (IS_ERR(filp)) {
put_unused_fd(fd);
return PTR_ERR(filp);
}
if (S_ISREG(inode->i_mode)) {
filp->f_flags |= O_NOATIME;
filp->f_mode |= FMODE_NOCMTIME;
}
fd_install(fd, filp);
return fd;
out_dput:
dput(dentry);
return error;
}
int
xfs_readlink_by_handle(
struct file *parfilp,
xfs_fsop_handlereq_t *hreq)
{
struct dentry *dentry;
__u32 olen;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
dentry = xfs_handlereq_to_dentry(parfilp, hreq);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
/* Restrict this handle operation to symlinks only. */
if (!d_is_symlink(dentry)) {
error = -EINVAL;
goto out_dput;
}
if (copy_from_user(&olen, hreq->ohandlen, sizeof(__u32))) {
error = -EFAULT;
goto out_dput;
}
error = vfs_readlink(dentry, hreq->ohandle, olen);
out_dput:
dput(dentry);
return error;
}
/*
* Format an attribute and copy it out to the user's buffer.
* Take care to check values and protect against them changing later,
* we may be reading them directly out of a user buffer.
*/
static void
xfs_ioc_attr_put_listent(
struct xfs_attr_list_context *context,
int flags,
unsigned char *name,
int namelen,
int valuelen)
{
struct xfs_attrlist *alist = context->buffer;
struct xfs_attrlist_ent *aep;
int arraytop;
ASSERT(!context->seen_enough);
ASSERT(context->count >= 0);
ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
ASSERT(context->firstu >= sizeof(*alist));
ASSERT(context->firstu <= context->bufsize);
/*
* Only list entries in the right namespace.
*/
if (context->attr_filter != (flags & XFS_ATTR_NSP_ONDISK_MASK))
return;
arraytop = sizeof(*alist) +
context->count * sizeof(alist->al_offset[0]);
/* decrement by the actual bytes used by the attr */
context->firstu -= round_up(offsetof(struct xfs_attrlist_ent, a_name) +
namelen + 1, sizeof(uint32_t));
if (context->firstu < arraytop) {
trace_xfs_attr_list_full(context);
alist->al_more = 1;
context->seen_enough = 1;
return;
}
aep = context->buffer + context->firstu;
aep->a_valuelen = valuelen;
memcpy(aep->a_name, name, namelen);
aep->a_name[namelen] = 0;
alist->al_offset[context->count++] = context->firstu;
alist->al_count = context->count;
trace_xfs_attr_list_add(context);
}
static unsigned int
xfs_attr_filter(
u32 ioc_flags)
{
if (ioc_flags & XFS_IOC_ATTR_ROOT)
return XFS_ATTR_ROOT;
if (ioc_flags & XFS_IOC_ATTR_SECURE)
return XFS_ATTR_SECURE;
return 0;
}
static unsigned int
xfs_attr_flags(
u32 ioc_flags)
{
if (ioc_flags & XFS_IOC_ATTR_CREATE)
return XATTR_CREATE;
if (ioc_flags & XFS_IOC_ATTR_REPLACE)
return XATTR_REPLACE;
return 0;
}
int
xfs_ioc_attr_list(
struct xfs_inode *dp,
void __user *ubuf,
size_t bufsize,
int flags,
struct xfs_attrlist_cursor __user *ucursor)
{
struct xfs_attr_list_context context = { };
struct xfs_attrlist *alist;
void *buffer;
int error;
if (bufsize < sizeof(struct xfs_attrlist) ||
bufsize > XFS_XATTR_LIST_MAX)
return -EINVAL;
/*
* Reject flags, only allow namespaces.
*/
if (flags & ~(XFS_IOC_ATTR_ROOT | XFS_IOC_ATTR_SECURE))
return -EINVAL;
if (flags == (XFS_IOC_ATTR_ROOT | XFS_IOC_ATTR_SECURE))
return -EINVAL;
/*
* Validate the cursor.
*/
if (copy_from_user(&context.cursor, ucursor, sizeof(context.cursor)))
return -EFAULT;
if (context.cursor.pad1 || context.cursor.pad2)
return -EINVAL;
if (!context.cursor.initted &&
(context.cursor.hashval || context.cursor.blkno ||
context.cursor.offset))
return -EINVAL;
buffer = kvzalloc(bufsize, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
/*
* Initialize the output buffer.
*/
context.dp = dp;
context.resynch = 1;
context.attr_filter = xfs_attr_filter(flags);
context.buffer = buffer;
context.bufsize = round_down(bufsize, sizeof(uint32_t));
context.firstu = context.bufsize;
context.put_listent = xfs_ioc_attr_put_listent;
alist = context.buffer;
alist->al_count = 0;
alist->al_more = 0;
alist->al_offset[0] = context.bufsize;
error = xfs_attr_list(&context);
if (error)
goto out_free;
if (copy_to_user(ubuf, buffer, bufsize) ||
copy_to_user(ucursor, &context.cursor, sizeof(context.cursor)))
error = -EFAULT;
out_free:
kmem_free(buffer);
return error;
}
STATIC int
xfs_attrlist_by_handle(
struct file *parfilp,
struct xfs_fsop_attrlist_handlereq __user *p)
{
struct xfs_fsop_attrlist_handlereq al_hreq;
struct dentry *dentry;
int error = -ENOMEM;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(&al_hreq, p, sizeof(al_hreq)))
return -EFAULT;
dentry = xfs_handlereq_to_dentry(parfilp, &al_hreq.hreq);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
error = xfs_ioc_attr_list(XFS_I(d_inode(dentry)), al_hreq.buffer,
al_hreq.buflen, al_hreq.flags, &p->pos);
dput(dentry);
return error;
}
static int
xfs_attrmulti_attr_get(
struct inode *inode,
unsigned char *name,
unsigned char __user *ubuf,
uint32_t *len,
uint32_t flags)
{
struct xfs_da_args args = {
.dp = XFS_I(inode),
.attr_filter = xfs_attr_filter(flags),
.attr_flags = xfs_attr_flags(flags),
.name = name,
.namelen = strlen(name),
.valuelen = *len,
};
int error;
if (*len > XFS_XATTR_SIZE_MAX)
return -EINVAL;
error = xfs_attr_get(&args);
if (error)
goto out_kfree;
*len = args.valuelen;
if (copy_to_user(ubuf, args.value, args.valuelen))
error = -EFAULT;
out_kfree:
kmem_free(args.value);
return error;
}
static int
xfs_attrmulti_attr_set(
struct inode *inode,
unsigned char *name,
const unsigned char __user *ubuf,
uint32_t len,
uint32_t flags)
{
struct xfs_da_args args = {
.dp = XFS_I(inode),
.attr_filter = xfs_attr_filter(flags),
.attr_flags = xfs_attr_flags(flags),
.name = name,
.namelen = strlen(name),
};
int error;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
return -EPERM;
if (ubuf) {
if (len > XFS_XATTR_SIZE_MAX)
return -EINVAL;
args.value = memdup_user(ubuf, len);
if (IS_ERR(args.value))
return PTR_ERR(args.value);
args.valuelen = len;
}
error = xfs_attr_change(&args);
if (!error && (flags & XFS_IOC_ATTR_ROOT))
xfs_forget_acl(inode, name);
kfree(args.value);
return error;
}
int
xfs_ioc_attrmulti_one(
struct file *parfilp,
struct inode *inode,
uint32_t opcode,
void __user *uname,
void __user *value,
uint32_t *len,
uint32_t flags)
{
unsigned char *name;
int error;
if ((flags & XFS_IOC_ATTR_ROOT) && (flags & XFS_IOC_ATTR_SECURE))
return -EINVAL;
name = strndup_user(uname, MAXNAMELEN);
if (IS_ERR(name))
return PTR_ERR(name);
switch (opcode) {
case ATTR_OP_GET:
error = xfs_attrmulti_attr_get(inode, name, value, len, flags);
break;
case ATTR_OP_REMOVE:
value = NULL;
*len = 0;
fallthrough;
case ATTR_OP_SET:
error = mnt_want_write_file(parfilp);
if (error)
break;
error = xfs_attrmulti_attr_set(inode, name, value, *len, flags);
mnt_drop_write_file(parfilp);
break;
default:
error = -EINVAL;
break;
}
kfree(name);
return error;
}
STATIC int
xfs_attrmulti_by_handle(
struct file *parfilp,
void __user *arg)
{
int error;
xfs_attr_multiop_t *ops;
xfs_fsop_attrmulti_handlereq_t am_hreq;
struct dentry *dentry;
unsigned int i, size;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(&am_hreq, arg, sizeof(xfs_fsop_attrmulti_handlereq_t)))
return -EFAULT;
/* overflow check */
if (am_hreq.opcount >= INT_MAX / sizeof(xfs_attr_multiop_t))
return -E2BIG;
dentry = xfs_handlereq_to_dentry(parfilp, &am_hreq.hreq);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
error = -E2BIG;
size = am_hreq.opcount * sizeof(xfs_attr_multiop_t);
if (!size || size > 16 * PAGE_SIZE)
goto out_dput;
ops = memdup_user(am_hreq.ops, size);
if (IS_ERR(ops)) {
error = PTR_ERR(ops);
goto out_dput;
}
error = 0;
for (i = 0; i < am_hreq.opcount; i++) {
ops[i].am_error = xfs_ioc_attrmulti_one(parfilp,
d_inode(dentry), ops[i].am_opcode,
ops[i].am_attrname, ops[i].am_attrvalue,
&ops[i].am_length, ops[i].am_flags);
}
if (copy_to_user(am_hreq.ops, ops, size))
error = -EFAULT;
kfree(ops);
out_dput:
dput(dentry);
return error;
}
/* Return 0 on success or positive error */
int
xfs_fsbulkstat_one_fmt(
struct xfs_ibulk *breq,
const struct xfs_bulkstat *bstat)
{
struct xfs_bstat bs1;
xfs_bulkstat_to_bstat(breq->mp, &bs1, bstat);
if (copy_to_user(breq->ubuffer, &bs1, sizeof(bs1)))
return -EFAULT;
return xfs_ibulk_advance(breq, sizeof(struct xfs_bstat));
}
int
xfs_fsinumbers_fmt(
struct xfs_ibulk *breq,
const struct xfs_inumbers *igrp)
{
struct xfs_inogrp ig1;
xfs_inumbers_to_inogrp(&ig1, igrp);
if (copy_to_user(breq->ubuffer, &ig1, sizeof(struct xfs_inogrp)))
return -EFAULT;
return xfs_ibulk_advance(breq, sizeof(struct xfs_inogrp));
}
STATIC int
xfs_ioc_fsbulkstat(
struct file *file,
unsigned int cmd,
void __user *arg)
{
struct xfs_mount *mp = XFS_I(file_inode(file))->i_mount;
struct xfs_fsop_bulkreq bulkreq;
struct xfs_ibulk breq = {
.mp = mp,
.idmap = file_mnt_idmap(file),
.ocount = 0,
};
xfs_ino_t lastino;
int error;
/* done = 1 if there are more stats to get and if bulkstat */
/* should be called again (unused here, but used in dmapi) */
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (xfs_is_shutdown(mp))
return -EIO;
if (copy_from_user(&bulkreq, arg, sizeof(struct xfs_fsop_bulkreq)))
return -EFAULT;
if (copy_from_user(&lastino, bulkreq.lastip, sizeof(__s64)))
return -EFAULT;
if (bulkreq.icount <= 0)
return -EINVAL;
if (bulkreq.ubuffer == NULL)
return -EINVAL;
breq.ubuffer = bulkreq.ubuffer;
breq.icount = bulkreq.icount;
/*
* FSBULKSTAT_SINGLE expects that *lastip contains the inode number
* that we want to stat. However, FSINUMBERS and FSBULKSTAT expect
* that *lastip contains either zero or the number of the last inode to
* be examined by the previous call and return results starting with
* the next inode after that. The new bulk request back end functions
* take the inode to start with, so we have to compute the startino
* parameter from lastino to maintain correct function. lastino == 0
* is a special case because it has traditionally meant "first inode
* in filesystem".
*/
if (cmd == XFS_IOC_FSINUMBERS) {
breq.startino = lastino ? lastino + 1 : 0;
error = xfs_inumbers(&breq, xfs_fsinumbers_fmt);
lastino = breq.startino - 1;
} else if (cmd == XFS_IOC_FSBULKSTAT_SINGLE) {
breq.startino = lastino;
breq.icount = 1;
error = xfs_bulkstat_one(&breq, xfs_fsbulkstat_one_fmt);
} else { /* XFS_IOC_FSBULKSTAT */
breq.startino = lastino ? lastino + 1 : 0;
error = xfs_bulkstat(&breq, xfs_fsbulkstat_one_fmt);
lastino = breq.startino - 1;
}
if (error)
return error;
if (bulkreq.lastip != NULL &&
copy_to_user(bulkreq.lastip, &lastino, sizeof(xfs_ino_t)))
return -EFAULT;
if (bulkreq.ocount != NULL &&
copy_to_user(bulkreq.ocount, &breq.ocount, sizeof(__s32)))
return -EFAULT;
return 0;
}
/* Return 0 on success or positive error */
static int
xfs_bulkstat_fmt(
struct xfs_ibulk *breq,
const struct xfs_bulkstat *bstat)
{
if (copy_to_user(breq->ubuffer, bstat, sizeof(struct xfs_bulkstat)))
return -EFAULT;
return xfs_ibulk_advance(breq, sizeof(struct xfs_bulkstat));
}
/*
* Check the incoming bulk request @hdr from userspace and initialize the
* internal @breq bulk request appropriately. Returns 0 if the bulk request
* should proceed; -ECANCELED if there's nothing to do; or the usual
* negative error code.
*/
static int
xfs_bulk_ireq_setup(
struct xfs_mount *mp,
const struct xfs_bulk_ireq *hdr,
struct xfs_ibulk *breq,
void __user *ubuffer)
{
if (hdr->icount == 0 ||
(hdr->flags & ~XFS_BULK_IREQ_FLAGS_ALL) ||
memchr_inv(hdr->reserved, 0, sizeof(hdr->reserved)))
return -EINVAL;
breq->startino = hdr->ino;
breq->ubuffer = ubuffer;
breq->icount = hdr->icount;
breq->ocount = 0;
breq->flags = 0;
/*
* The @ino parameter is a special value, so we must look it up here.
* We're not allowed to have IREQ_AGNO, and we only return one inode
* worth of data.
*/
if (hdr->flags & XFS_BULK_IREQ_SPECIAL) {
if (hdr->flags & XFS_BULK_IREQ_AGNO)
return -EINVAL;
switch (hdr->ino) {
case XFS_BULK_IREQ_SPECIAL_ROOT:
breq->startino = mp->m_sb.sb_rootino;
break;
default:
return -EINVAL;
}
breq->icount = 1;
}
/*
* The IREQ_AGNO flag means that we only want results from a given AG.
* If @hdr->ino is zero, we start iterating in that AG. If @hdr->ino is
* beyond the specified AG then we return no results.
*/
if (hdr->flags & XFS_BULK_IREQ_AGNO) {
if (hdr->agno >= mp->m_sb.sb_agcount)
return -EINVAL;
if (breq->startino == 0)
breq->startino = XFS_AGINO_TO_INO(mp, hdr->agno, 0);
else if (XFS_INO_TO_AGNO(mp, breq->startino) < hdr->agno)
return -EINVAL;
breq->flags |= XFS_IBULK_SAME_AG;
/* Asking for an inode past the end of the AG? We're done! */
if (XFS_INO_TO_AGNO(mp, breq->startino) > hdr->agno)
return -ECANCELED;
} else if (hdr->agno)
return -EINVAL;
/* Asking for an inode past the end of the FS? We're done! */
if (XFS_INO_TO_AGNO(mp, breq->startino) >= mp->m_sb.sb_agcount)
return -ECANCELED;
if (hdr->flags & XFS_BULK_IREQ_NREXT64)
breq->flags |= XFS_IBULK_NREXT64;
return 0;
}
/*
* Update the userspace bulk request @hdr to reflect the end state of the
* internal bulk request @breq.
*/
static void
xfs_bulk_ireq_teardown(
struct xfs_bulk_ireq *hdr,
struct xfs_ibulk *breq)
{
hdr->ino = breq->startino;
hdr->ocount = breq->ocount;
}
/* Handle the v5 bulkstat ioctl. */
STATIC int
xfs_ioc_bulkstat(
struct file *file,
unsigned int cmd,
struct xfs_bulkstat_req __user *arg)
{
struct xfs_mount *mp = XFS_I(file_inode(file))->i_mount;
struct xfs_bulk_ireq hdr;
struct xfs_ibulk breq = {
.mp = mp,
.idmap = file_mnt_idmap(file),
};
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (xfs_is_shutdown(mp))
return -EIO;
if (copy_from_user(&hdr, &arg->hdr, sizeof(hdr)))
return -EFAULT;
error = xfs_bulk_ireq_setup(mp, &hdr, &breq, arg->bulkstat);
if (error == -ECANCELED)
goto out_teardown;
if (error < 0)
return error;
error = xfs_bulkstat(&breq, xfs_bulkstat_fmt);
if (error)
return error;
out_teardown:
xfs_bulk_ireq_teardown(&hdr, &breq);
if (copy_to_user(&arg->hdr, &hdr, sizeof(hdr)))
return -EFAULT;
return 0;
}
STATIC int
xfs_inumbers_fmt(
struct xfs_ibulk *breq,
const struct xfs_inumbers *igrp)
{
if (copy_to_user(breq->ubuffer, igrp, sizeof(struct xfs_inumbers)))
return -EFAULT;
return xfs_ibulk_advance(breq, sizeof(struct xfs_inumbers));
}
/* Handle the v5 inumbers ioctl. */
STATIC int
xfs_ioc_inumbers(
struct xfs_mount *mp,
unsigned int cmd,
struct xfs_inumbers_req __user *arg)
{
struct xfs_bulk_ireq hdr;
struct xfs_ibulk breq = {
.mp = mp,
};
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (xfs_is_shutdown(mp))
return -EIO;
if (copy_from_user(&hdr, &arg->hdr, sizeof(hdr)))
return -EFAULT;
error = xfs_bulk_ireq_setup(mp, &hdr, &breq, arg->inumbers);
if (error == -ECANCELED)
goto out_teardown;
if (error < 0)
return error;
error = xfs_inumbers(&breq, xfs_inumbers_fmt);
if (error)
return error;
out_teardown:
xfs_bulk_ireq_teardown(&hdr, &breq);
if (copy_to_user(&arg->hdr, &hdr, sizeof(hdr)))
return -EFAULT;
return 0;
}
STATIC int
xfs_ioc_fsgeometry(
struct xfs_mount *mp,
void __user *arg,
int struct_version)
{
struct xfs_fsop_geom fsgeo;
size_t len;
xfs_fs_geometry(mp, &fsgeo, struct_version);
if (struct_version <= 3)
len = sizeof(struct xfs_fsop_geom_v1);
else if (struct_version == 4)
len = sizeof(struct xfs_fsop_geom_v4);
else {
xfs_fsop_geom_health(mp, &fsgeo);
len = sizeof(fsgeo);
}
if (copy_to_user(arg, &fsgeo, len))
return -EFAULT;
return 0;
}
STATIC int
xfs_ioc_ag_geometry(
struct xfs_mount *mp,
void __user *arg)
{
struct xfs_perag *pag;
struct xfs_ag_geometry ageo;
int error;
if (copy_from_user(&ageo, arg, sizeof(ageo)))
return -EFAULT;
if (ageo.ag_flags)
return -EINVAL;
if (memchr_inv(&ageo.ag_reserved, 0, sizeof(ageo.ag_reserved)))
return -EINVAL;
pag = xfs_perag_get(mp, ageo.ag_number);
if (!pag)
return -EINVAL;
error = xfs_ag_get_geometry(pag, &ageo);
xfs_perag_put(pag);
if (error)
return error;
if (copy_to_user(arg, &ageo, sizeof(ageo)))
return -EFAULT;
return 0;
}
/*
* Linux extended inode flags interface.
*/
static void
xfs_fill_fsxattr(
struct xfs_inode *ip,
int whichfork,
struct fileattr *fa)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
fileattr_fill_xflags(fa, xfs_ip2xflags(ip));
if (ip->i_diflags & XFS_DIFLAG_EXTSIZE) {
fa->fsx_extsize = XFS_FSB_TO_B(mp, ip->i_extsize);
} else if (ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT) {
/*
* Don't let a misaligned extent size hint on a directory
* escape to userspace if it won't pass the setattr checks
* later.
*/
if ((ip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
ip->i_extsize % mp->m_sb.sb_rextsize > 0) {
fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE |
FS_XFLAG_EXTSZINHERIT);
fa->fsx_extsize = 0;
} else {
fa->fsx_extsize = XFS_FSB_TO_B(mp, ip->i_extsize);
}
}
if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE)
fa->fsx_cowextsize = XFS_FSB_TO_B(mp, ip->i_cowextsize);
fa->fsx_projid = ip->i_projid;
if (ifp && !xfs_need_iread_extents(ifp))
fa->fsx_nextents = xfs_iext_count(ifp);
else
fa->fsx_nextents = xfs_ifork_nextents(ifp);
}
STATIC int
xfs_ioc_fsgetxattra(
xfs_inode_t *ip,
void __user *arg)
{
struct fileattr fa;
xfs_ilock(ip, XFS_ILOCK_SHARED);
xfs_fill_fsxattr(ip, XFS_ATTR_FORK, &fa);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
return copy_fsxattr_to_user(&fa, arg);
}
int
xfs_fileattr_get(
struct dentry *dentry,
struct fileattr *fa)
{
struct xfs_inode *ip = XFS_I(d_inode(dentry));
if (d_is_special(dentry))
return -ENOTTY;
xfs_ilock(ip, XFS_ILOCK_SHARED);
xfs_fill_fsxattr(ip, XFS_DATA_FORK, fa);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
return 0;
}
STATIC uint16_t
xfs_flags2diflags(
struct xfs_inode *ip,
unsigned int xflags)
{
/* can't set PREALLOC this way, just preserve it */
uint16_t di_flags =
(ip->i_diflags & XFS_DIFLAG_PREALLOC);
if (xflags & FS_XFLAG_IMMUTABLE)
di_flags |= XFS_DIFLAG_IMMUTABLE;
if (xflags & FS_XFLAG_APPEND)
di_flags |= XFS_DIFLAG_APPEND;
if (xflags & FS_XFLAG_SYNC)
di_flags |= XFS_DIFLAG_SYNC;
if (xflags & FS_XFLAG_NOATIME)
di_flags |= XFS_DIFLAG_NOATIME;
if (xflags & FS_XFLAG_NODUMP)
di_flags |= XFS_DIFLAG_NODUMP;
if (xflags & FS_XFLAG_NODEFRAG)
di_flags |= XFS_DIFLAG_NODEFRAG;
if (xflags & FS_XFLAG_FILESTREAM)
di_flags |= XFS_DIFLAG_FILESTREAM;
if (S_ISDIR(VFS_I(ip)->i_mode)) {
if (xflags & FS_XFLAG_RTINHERIT)
di_flags |= XFS_DIFLAG_RTINHERIT;
if (xflags & FS_XFLAG_NOSYMLINKS)
di_flags |= XFS_DIFLAG_NOSYMLINKS;
if (xflags & FS_XFLAG_EXTSZINHERIT)
di_flags |= XFS_DIFLAG_EXTSZINHERIT;
if (xflags & FS_XFLAG_PROJINHERIT)
di_flags |= XFS_DIFLAG_PROJINHERIT;
} else if (S_ISREG(VFS_I(ip)->i_mode)) {
if (xflags & FS_XFLAG_REALTIME)
di_flags |= XFS_DIFLAG_REALTIME;
if (xflags & FS_XFLAG_EXTSIZE)
di_flags |= XFS_DIFLAG_EXTSIZE;
}
return di_flags;
}
STATIC uint64_t
xfs_flags2diflags2(
struct xfs_inode *ip,
unsigned int xflags)
{
uint64_t di_flags2 =
(ip->i_diflags2 & (XFS_DIFLAG2_REFLINK |
XFS_DIFLAG2_BIGTIME |
XFS_DIFLAG2_NREXT64));
if (xflags & FS_XFLAG_DAX)
di_flags2 |= XFS_DIFLAG2_DAX;
if (xflags & FS_XFLAG_COWEXTSIZE)
di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
return di_flags2;
}
static int
xfs_ioctl_setattr_xflags(
struct xfs_trans *tp,
struct xfs_inode *ip,
struct fileattr *fa)
{
struct xfs_mount *mp = ip->i_mount;
uint64_t i_flags2;
/* Can't change realtime flag if any extents are allocated. */
if ((ip->i_df.if_nextents || ip->i_delayed_blks) &&
XFS_IS_REALTIME_INODE(ip) != (fa->fsx_xflags & FS_XFLAG_REALTIME))
return -EINVAL;
/* If realtime flag is set then must have realtime device */
if (fa->fsx_xflags & FS_XFLAG_REALTIME) {
if (mp->m_sb.sb_rblocks == 0 || mp->m_sb.sb_rextsize == 0 ||
(ip->i_extsize % mp->m_sb.sb_rextsize))
return -EINVAL;
}
/* Clear reflink if we are actually able to set the rt flag. */
if ((fa->fsx_xflags & FS_XFLAG_REALTIME) && xfs_is_reflink_inode(ip))
ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
/* diflags2 only valid for v3 inodes. */
i_flags2 = xfs_flags2diflags2(ip, fa->fsx_xflags);
if (i_flags2 && !xfs_has_v3inodes(mp))
return -EINVAL;
ip->i_diflags = xfs_flags2diflags(ip, fa->fsx_xflags);
ip->i_diflags2 = i_flags2;
xfs_diflags_to_iflags(ip, false);
xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
XFS_STATS_INC(mp, xs_ig_attrchg);
return 0;
}
static void
xfs_ioctl_setattr_prepare_dax(
struct xfs_inode *ip,
struct fileattr *fa)
{
struct xfs_mount *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);
if (S_ISDIR(inode->i_mode))
return;
if (xfs_has_dax_always(mp) || xfs_has_dax_never(mp))
return;
if (((fa->fsx_xflags & FS_XFLAG_DAX) &&
!(ip->i_diflags2 & XFS_DIFLAG2_DAX)) ||
(!(fa->fsx_xflags & FS_XFLAG_DAX) &&
(ip->i_diflags2 & XFS_DIFLAG2_DAX)))
d_mark_dontcache(inode);
}
/*
* Set up the transaction structure for the setattr operation, checking that we
* have permission to do so. On success, return a clean transaction and the
* inode locked exclusively ready for further operation specific checks. On
* failure, return an error without modifying or locking the inode.
*/
static struct xfs_trans *
xfs_ioctl_setattr_get_trans(
struct xfs_inode *ip,
struct xfs_dquot *pdqp)
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int error = -EROFS;
if (xfs_is_readonly(mp))
goto out_error;
error = -EIO;
if (xfs_is_shutdown(mp))
goto out_error;
error = xfs_trans_alloc_ichange(ip, NULL, NULL, pdqp,
has_capability_noaudit(current, CAP_FOWNER), &tp);
if (error)
goto out_error;
if (xfs_has_wsync(mp))
xfs_trans_set_sync(tp);
return tp;
out_error:
return ERR_PTR(error);
}
/*
* Validate a proposed extent size hint. For regular files, the hint can only
* be changed if no extents are allocated.
*/
static int
xfs_ioctl_setattr_check_extsize(
struct xfs_inode *ip,
struct fileattr *fa)
{
struct xfs_mount *mp = ip->i_mount;
xfs_failaddr_t failaddr;
uint16_t new_diflags;
if (!fa->fsx_valid)
return 0;
if (S_ISREG(VFS_I(ip)->i_mode) && ip->i_df.if_nextents &&
XFS_FSB_TO_B(mp, ip->i_extsize) != fa->fsx_extsize)
return -EINVAL;
if (fa->fsx_extsize & mp->m_blockmask)
return -EINVAL;
new_diflags = xfs_flags2diflags(ip, fa->fsx_xflags);
/*
* Inode verifiers do not check that the extent size hint is an integer
* multiple of the rt extent size on a directory with both rtinherit
* and extszinherit flags set. Don't let sysadmins misconfigure
* directories.
*/
if ((new_diflags & XFS_DIFLAG_RTINHERIT) &&
(new_diflags & XFS_DIFLAG_EXTSZINHERIT)) {
unsigned int rtextsize_bytes;
rtextsize_bytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
if (fa->fsx_extsize % rtextsize_bytes)
return -EINVAL;
}
failaddr = xfs_inode_validate_extsize(ip->i_mount,
XFS_B_TO_FSB(mp, fa->fsx_extsize),
VFS_I(ip)->i_mode, new_diflags);
return failaddr != NULL ? -EINVAL : 0;
}
static int
xfs_ioctl_setattr_check_cowextsize(
struct xfs_inode *ip,
struct fileattr *fa)
{
struct xfs_mount *mp = ip->i_mount;
xfs_failaddr_t failaddr;
uint64_t new_diflags2;
uint16_t new_diflags;
if (!fa->fsx_valid)
return 0;
if (fa->fsx_cowextsize & mp->m_blockmask)
return -EINVAL;
new_diflags = xfs_flags2diflags(ip, fa->fsx_xflags);
new_diflags2 = xfs_flags2diflags2(ip, fa->fsx_xflags);
failaddr = xfs_inode_validate_cowextsize(ip->i_mount,
XFS_B_TO_FSB(mp, fa->fsx_cowextsize),
VFS_I(ip)->i_mode, new_diflags, new_diflags2);
return failaddr != NULL ? -EINVAL : 0;
}
static int
xfs_ioctl_setattr_check_projid(
struct xfs_inode *ip,
struct fileattr *fa)
{
if (!fa->fsx_valid)
return 0;
/* Disallow 32bit project ids if 32bit IDs are not enabled. */
if (fa->fsx_projid > (uint16_t)-1 &&
!xfs_has_projid32(ip->i_mount))
return -EINVAL;
return 0;
}
int
xfs_fileattr_set(
struct mnt_idmap *idmap,
struct dentry *dentry,
struct fileattr *fa)
{
struct xfs_inode *ip = XFS_I(d_inode(dentry));
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
struct xfs_dquot *pdqp = NULL;
struct xfs_dquot *olddquot = NULL;
int error;
trace_xfs_ioctl_setattr(ip);
if (d_is_special(dentry))
return -ENOTTY;
if (!fa->fsx_valid) {
if (fa->flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL |
FS_NOATIME_FL | FS_NODUMP_FL |
FS_SYNC_FL | FS_DAX_FL | FS_PROJINHERIT_FL))
return -EOPNOTSUPP;
}
error = xfs_ioctl_setattr_check_projid(ip, fa);
if (error)
return error;
/*
* If disk quotas is on, we make sure that the dquots do exist on disk,
* before we start any other transactions. Trying to do this later
* is messy. We don't care to take a readlock to look at the ids
* in inode here, because we can't hold it across the trans_reserve.
* If the IDs do change before we take the ilock, we're covered
* because the i_*dquot fields will get updated anyway.
*/
if (fa->fsx_valid && XFS_IS_QUOTA_ON(mp)) {
error = xfs_qm_vop_dqalloc(ip, VFS_I(ip)->i_uid,
VFS_I(ip)->i_gid, fa->fsx_projid,
XFS_QMOPT_PQUOTA, NULL, NULL, &pdqp);
if (error)
return error;
}
xfs_ioctl_setattr_prepare_dax(ip, fa);
tp = xfs_ioctl_setattr_get_trans(ip, pdqp);
if (IS_ERR(tp)) {
error = PTR_ERR(tp);
goto error_free_dquots;
}
error = xfs_ioctl_setattr_check_extsize(ip, fa);
if (error)
goto error_trans_cancel;
error = xfs_ioctl_setattr_check_cowextsize(ip, fa);
if (error)
goto error_trans_cancel;
error = xfs_ioctl_setattr_xflags(tp, ip, fa);
if (error)
goto error_trans_cancel;
if (!fa->fsx_valid)
goto skip_xattr;
/*
* Change file ownership. Must be the owner or privileged. CAP_FSETID
* overrides the following restrictions:
*
* The set-user-ID and set-group-ID bits of a file will be cleared upon
* successful return from chown()
*/
if ((VFS_I(ip)->i_mode & (S_ISUID|S_ISGID)) &&
!capable_wrt_inode_uidgid(idmap, VFS_I(ip), CAP_FSETID))
VFS_I(ip)->i_mode &= ~(S_ISUID|S_ISGID);
/* Change the ownerships and register project quota modifications */
if (ip->i_projid != fa->fsx_projid) {
if (XFS_IS_PQUOTA_ON(mp)) {
olddquot = xfs_qm_vop_chown(tp, ip,
&ip->i_pdquot, pdqp);
}
ip->i_projid = fa->fsx_projid;
}
/*
* Only set the extent size hint if we've already determined that the
* extent size hint should be set on the inode. If no extent size flags
* are set on the inode then unconditionally clear the extent size hint.
*/
if (ip->i_diflags & (XFS_DIFLAG_EXTSIZE | XFS_DIFLAG_EXTSZINHERIT))
ip->i_extsize = XFS_B_TO_FSB(mp, fa->fsx_extsize);
else
ip->i_extsize = 0;
if (xfs_has_v3inodes(mp)) {
if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE)
ip->i_cowextsize = XFS_B_TO_FSB(mp, fa->fsx_cowextsize);
else
ip->i_cowextsize = 0;
}
skip_xattr:
error = xfs_trans_commit(tp);
/*
* Release any dquot(s) the inode had kept before chown.
*/
xfs_qm_dqrele(olddquot);
xfs_qm_dqrele(pdqp);
return error;
error_trans_cancel:
xfs_trans_cancel(tp);
error_free_dquots:
xfs_qm_dqrele(pdqp);
return error;
}
static bool
xfs_getbmap_format(
struct kgetbmap *p,
struct getbmapx __user *u,
size_t recsize)
{
if (put_user(p->bmv_offset, &u->bmv_offset) ||
put_user(p->bmv_block, &u->bmv_block) ||
put_user(p->bmv_length, &u->bmv_length) ||
put_user(0, &u->bmv_count) ||
put_user(0, &u->bmv_entries))
return false;
if (recsize < sizeof(struct getbmapx))
return true;
if (put_user(0, &u->bmv_iflags) ||
put_user(p->bmv_oflags, &u->bmv_oflags) ||
put_user(0, &u->bmv_unused1) ||
put_user(0, &u->bmv_unused2))
return false;
return true;
}
STATIC int
xfs_ioc_getbmap(
struct file *file,
unsigned int cmd,
void __user *arg)
{
struct getbmapx bmx = { 0 };
struct kgetbmap *buf;
size_t recsize;
int error, i;
switch (cmd) {
case XFS_IOC_GETBMAPA:
bmx.bmv_iflags = BMV_IF_ATTRFORK;
fallthrough;
case XFS_IOC_GETBMAP:
/* struct getbmap is a strict subset of struct getbmapx. */
recsize = sizeof(struct getbmap);
break;
case XFS_IOC_GETBMAPX:
recsize = sizeof(struct getbmapx);
break;
default:
return -EINVAL;
}
if (copy_from_user(&bmx, arg, recsize))
return -EFAULT;
if (bmx.bmv_count < 2)
return -EINVAL;
if (bmx.bmv_count >= INT_MAX / recsize)
return -ENOMEM;
buf = kvcalloc(bmx.bmv_count, sizeof(*buf), GFP_KERNEL);
if (!buf)
return -ENOMEM;
error = xfs_getbmap(XFS_I(file_inode(file)), &bmx, buf);
if (error)
goto out_free_buf;
error = -EFAULT;
if (copy_to_user(arg, &bmx, recsize))
goto out_free_buf;
arg += recsize;
for (i = 0; i < bmx.bmv_entries; i++) {
if (!xfs_getbmap_format(buf + i, arg, recsize))
goto out_free_buf;
arg += recsize;
}
error = 0;
out_free_buf:
kmem_free(buf);
return error;
}
STATIC int
xfs_ioc_getfsmap(
struct xfs_inode *ip,
struct fsmap_head __user *arg)
{
struct xfs_fsmap_head xhead = {0};
struct fsmap_head head;
struct fsmap *recs;
unsigned int count;
__u32 last_flags = 0;
bool done = false;
int error;
if (copy_from_user(&head, arg, sizeof(struct fsmap_head)))
return -EFAULT;
if (memchr_inv(head.fmh_reserved, 0, sizeof(head.fmh_reserved)) ||
memchr_inv(head.fmh_keys[0].fmr_reserved, 0,
sizeof(head.fmh_keys[0].fmr_reserved)) ||
memchr_inv(head.fmh_keys[1].fmr_reserved, 0,
sizeof(head.fmh_keys[1].fmr_reserved)))
return -EINVAL;
/*
* Use an internal memory buffer so that we don't have to copy fsmap
* data to userspace while holding locks. Start by trying to allocate
* up to 128k for the buffer, but fall back to a single page if needed.
*/
count = min_t(unsigned int, head.fmh_count,
131072 / sizeof(struct fsmap));
recs = kvcalloc(count, sizeof(struct fsmap), GFP_KERNEL);
if (!recs) {
count = min_t(unsigned int, head.fmh_count,
PAGE_SIZE / sizeof(struct fsmap));
recs = kvcalloc(count, sizeof(struct fsmap), GFP_KERNEL);
if (!recs)
return -ENOMEM;
}
xhead.fmh_iflags = head.fmh_iflags;
xfs_fsmap_to_internal(&xhead.fmh_keys[0], &head.fmh_keys[0]);
xfs_fsmap_to_internal(&xhead.fmh_keys[1], &head.fmh_keys[1]);
trace_xfs_getfsmap_low_key(ip->i_mount, &xhead.fmh_keys[0]);
trace_xfs_getfsmap_high_key(ip->i_mount, &xhead.fmh_keys[1]);
head.fmh_entries = 0;
do {
struct fsmap __user *user_recs;
struct fsmap *last_rec;
user_recs = &arg->fmh_recs[head.fmh_entries];
xhead.fmh_entries = 0;
xhead.fmh_count = min_t(unsigned int, count,
head.fmh_count - head.fmh_entries);
/* Run query, record how many entries we got. */
error = xfs_getfsmap(ip->i_mount, &xhead, recs);
switch (error) {
case 0:
/*
* There are no more records in the result set. Copy
* whatever we got to userspace and break out.
*/
done = true;
break;
case -ECANCELED:
/*
* The internal memory buffer is full. Copy whatever
* records we got to userspace and go again if we have
* not yet filled the userspace buffer.
*/
error = 0;
break;
default:
goto out_free;
}
head.fmh_entries += xhead.fmh_entries;
head.fmh_oflags = xhead.fmh_oflags;
/*
* If the caller wanted a record count or there aren't any
* new records to return, we're done.
*/
if (head.fmh_count == 0 || xhead.fmh_entries == 0)
break;
/* Copy all the records we got out to userspace. */
if (copy_to_user(user_recs, recs,
xhead.fmh_entries * sizeof(struct fsmap))) {
error = -EFAULT;
goto out_free;
}
/* Remember the last record flags we copied to userspace. */
last_rec = &recs[xhead.fmh_entries - 1];
last_flags = last_rec->fmr_flags;
/* Set up the low key for the next iteration. */
xfs_fsmap_to_internal(&xhead.fmh_keys[0], last_rec);
trace_xfs_getfsmap_low_key(ip->i_mount, &xhead.fmh_keys[0]);
} while (!done && head.fmh_entries < head.fmh_count);
/*
* If there are no more records in the query result set and we're not
* in counting mode, mark the last record returned with the LAST flag.
*/
if (done && head.fmh_count > 0 && head.fmh_entries > 0) {
struct fsmap __user *user_rec;
last_flags |= FMR_OF_LAST;
user_rec = &arg->fmh_recs[head.fmh_entries - 1];
if (copy_to_user(&user_rec->fmr_flags, &last_flags,
sizeof(last_flags))) {
error = -EFAULT;
goto out_free;
}
}
/* copy back header */
if (copy_to_user(arg, &head, sizeof(struct fsmap_head))) {
error = -EFAULT;
goto out_free;
}
out_free:
kmem_free(recs);
return error;
}
STATIC int
xfs_ioc_scrub_metadata(
struct file *file,
void __user *arg)
{
struct xfs_scrub_metadata scrub;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(&scrub, arg, sizeof(scrub)))
return -EFAULT;
error = xfs_scrub_metadata(file, &scrub);
if (error)
return error;
if (copy_to_user(arg, &scrub, sizeof(scrub)))
return -EFAULT;
return 0;
}
int
xfs_ioc_swapext(
xfs_swapext_t *sxp)
{
xfs_inode_t *ip, *tip;
struct fd f, tmp;
int error = 0;
/* Pull information for the target fd */
f = fdget((int)sxp->sx_fdtarget);
if (!f.file) {
error = -EINVAL;
goto out;
}
if (!(f.file->f_mode & FMODE_WRITE) ||
!(f.file->f_mode & FMODE_READ) ||
(f.file->f_flags & O_APPEND)) {
error = -EBADF;
goto out_put_file;
}
tmp = fdget((int)sxp->sx_fdtmp);
if (!tmp.file) {
error = -EINVAL;
goto out_put_file;
}
if (!(tmp.file->f_mode & FMODE_WRITE) ||
!(tmp.file->f_mode & FMODE_READ) ||
(tmp.file->f_flags & O_APPEND)) {
error = -EBADF;
goto out_put_tmp_file;
}
if (IS_SWAPFILE(file_inode(f.file)) ||
IS_SWAPFILE(file_inode(tmp.file))) {
error = -EINVAL;
goto out_put_tmp_file;
}
/*
* We need to ensure that the fds passed in point to XFS inodes
* before we cast and access them as XFS structures as we have no
* control over what the user passes us here.
*/
if (f.file->f_op != &xfs_file_operations ||
tmp.file->f_op != &xfs_file_operations) {
error = -EINVAL;
goto out_put_tmp_file;
}
ip = XFS_I(file_inode(f.file));
tip = XFS_I(file_inode(tmp.file));
if (ip->i_mount != tip->i_mount) {
error = -EINVAL;
goto out_put_tmp_file;
}
if (ip->i_ino == tip->i_ino) {
error = -EINVAL;
goto out_put_tmp_file;
}
if (xfs_is_shutdown(ip->i_mount)) {
error = -EIO;
goto out_put_tmp_file;
}
error = xfs_swap_extents(ip, tip, sxp);
out_put_tmp_file:
fdput(tmp);
out_put_file:
fdput(f);
out:
return error;
}
static int
xfs_ioc_getlabel(
struct xfs_mount *mp,
char __user *user_label)
{
struct xfs_sb *sbp = &mp->m_sb;
char label[XFSLABEL_MAX + 1];
/* Paranoia */
BUILD_BUG_ON(sizeof(sbp->sb_fname) > FSLABEL_MAX);
/* 1 larger than sb_fname, so this ensures a trailing NUL char */
memset(label, 0, sizeof(label));
spin_lock(&mp->m_sb_lock);
strncpy(label, sbp->sb_fname, XFSLABEL_MAX);
spin_unlock(&mp->m_sb_lock);
if (copy_to_user(user_label, label, sizeof(label)))
return -EFAULT;
return 0;
}
static int
xfs_ioc_setlabel(
struct file *filp,
struct xfs_mount *mp,
char __user *newlabel)
{
struct xfs_sb *sbp = &mp->m_sb;
char label[XFSLABEL_MAX + 1];
size_t len;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/*
* The generic ioctl allows up to FSLABEL_MAX chars, but XFS is much
* smaller, at 12 bytes. We copy one more to be sure we find the
* (required) NULL character to test the incoming label length.
* NB: The on disk label doesn't need to be null terminated.
*/
if (copy_from_user(label, newlabel, XFSLABEL_MAX + 1))
return -EFAULT;
len = strnlen(label, XFSLABEL_MAX + 1);
if (len > sizeof(sbp->sb_fname))
return -EINVAL;
error = mnt_want_write_file(filp);
if (error)
return error;
spin_lock(&mp->m_sb_lock);
memset(sbp->sb_fname, 0, sizeof(sbp->sb_fname));
memcpy(sbp->sb_fname, label, len);
spin_unlock(&mp->m_sb_lock);
/*
* Now we do several things to satisfy userspace.
* In addition to normal logging of the primary superblock, we also
* immediately write these changes to sector zero for the primary, then
* update all backup supers (as xfs_db does for a label change), then
* invalidate the block device page cache. This is so that any prior
* buffered reads from userspace (i.e. from blkid) are invalidated,
* and userspace will see the newly-written label.
*/
error = xfs_sync_sb_buf(mp);
if (error)
goto out;
/*
* growfs also updates backup supers so lock against that.
*/
mutex_lock(&mp->m_growlock);
error = xfs_update_secondary_sbs(mp);
mutex_unlock(&mp->m_growlock);
invalidate_bdev(mp->m_ddev_targp->bt_bdev);
out:
mnt_drop_write_file(filp);
return error;
}
static inline int
xfs_fs_eofblocks_from_user(
struct xfs_fs_eofblocks *src,
struct xfs_icwalk *dst)
{
if (src->eof_version != XFS_EOFBLOCKS_VERSION)
return -EINVAL;
if (src->eof_flags & ~XFS_EOF_FLAGS_VALID)
return -EINVAL;
if (memchr_inv(&src->pad32, 0, sizeof(src->pad32)) ||
memchr_inv(src->pad64, 0, sizeof(src->pad64)))
return -EINVAL;
dst->icw_flags = 0;
if (src->eof_flags & XFS_EOF_FLAGS_SYNC)
dst->icw_flags |= XFS_ICWALK_FLAG_SYNC;
if (src->eof_flags & XFS_EOF_FLAGS_UID)
dst->icw_flags |= XFS_ICWALK_FLAG_UID;
if (src->eof_flags & XFS_EOF_FLAGS_GID)
dst->icw_flags |= XFS_ICWALK_FLAG_GID;
if (src->eof_flags & XFS_EOF_FLAGS_PRID)
dst->icw_flags |= XFS_ICWALK_FLAG_PRID;
if (src->eof_flags & XFS_EOF_FLAGS_MINFILESIZE)
dst->icw_flags |= XFS_ICWALK_FLAG_MINFILESIZE;
dst->icw_prid = src->eof_prid;
dst->icw_min_file_size = src->eof_min_file_size;
dst->icw_uid = INVALID_UID;
if (src->eof_flags & XFS_EOF_FLAGS_UID) {
dst->icw_uid = make_kuid(current_user_ns(), src->eof_uid);
if (!uid_valid(dst->icw_uid))
return -EINVAL;
}
dst->icw_gid = INVALID_GID;
if (src->eof_flags & XFS_EOF_FLAGS_GID) {
dst->icw_gid = make_kgid(current_user_ns(), src->eof_gid);
if (!gid_valid(dst->icw_gid))
return -EINVAL;
}
return 0;
}
/*
* These long-unused ioctls were removed from the official ioctl API in 5.17,
* but retain these definitions so that we can log warnings about them.
*/
#define XFS_IOC_ALLOCSP _IOW ('X', 10, struct xfs_flock64)
#define XFS_IOC_FREESP _IOW ('X', 11, struct xfs_flock64)
#define XFS_IOC_ALLOCSP64 _IOW ('X', 36, struct xfs_flock64)
#define XFS_IOC_FREESP64 _IOW ('X', 37, struct xfs_flock64)
/*
* Note: some of the ioctl's return positive numbers as a
* byte count indicating success, such as readlink_by_handle.
* So we don't "sign flip" like most other routines. This means
* true errors need to be returned as a negative value.
*/
long
xfs_file_ioctl(
struct file *filp,
unsigned int cmd,
unsigned long p)
{
struct inode *inode = file_inode(filp);
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
void __user *arg = (void __user *)p;
int error;
trace_xfs_file_ioctl(ip);
switch (cmd) {
case FITRIM:
return xfs_ioc_trim(mp, arg);
case FS_IOC_GETFSLABEL:
return xfs_ioc_getlabel(mp, arg);
case FS_IOC_SETFSLABEL:
return xfs_ioc_setlabel(filp, mp, arg);
case XFS_IOC_ALLOCSP:
case XFS_IOC_FREESP:
case XFS_IOC_ALLOCSP64:
case XFS_IOC_FREESP64:
xfs_warn_once(mp,
"%s should use fallocate; XFS_IOC_{ALLOC,FREE}SP ioctl unsupported",
current->comm);
return -ENOTTY;
case XFS_IOC_DIOINFO: {
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
struct dioattr da;
da.d_mem = da.d_miniosz = target->bt_logical_sectorsize;
da.d_maxiosz = INT_MAX & ~(da.d_miniosz - 1);
if (copy_to_user(arg, &da, sizeof(da)))
return -EFAULT;
return 0;
}
case XFS_IOC_FSBULKSTAT_SINGLE:
case XFS_IOC_FSBULKSTAT:
case XFS_IOC_FSINUMBERS:
return xfs_ioc_fsbulkstat(filp, cmd, arg);
case XFS_IOC_BULKSTAT:
return xfs_ioc_bulkstat(filp, cmd, arg);
case XFS_IOC_INUMBERS:
return xfs_ioc_inumbers(mp, cmd, arg);
case XFS_IOC_FSGEOMETRY_V1:
return xfs_ioc_fsgeometry(mp, arg, 3);
case XFS_IOC_FSGEOMETRY_V4:
return xfs_ioc_fsgeometry(mp, arg, 4);
case XFS_IOC_FSGEOMETRY:
return xfs_ioc_fsgeometry(mp, arg, 5);
case XFS_IOC_AG_GEOMETRY:
return xfs_ioc_ag_geometry(mp, arg);
case XFS_IOC_GETVERSION:
return put_user(inode->i_generation, (int __user *)arg);
case XFS_IOC_FSGETXATTRA:
return xfs_ioc_fsgetxattra(ip, arg);
case XFS_IOC_GETBMAP:
case XFS_IOC_GETBMAPA:
case XFS_IOC_GETBMAPX:
return xfs_ioc_getbmap(filp, cmd, arg);
case FS_IOC_GETFSMAP:
return xfs_ioc_getfsmap(ip, arg);
case XFS_IOC_SCRUB_METADATA:
return xfs_ioc_scrub_metadata(filp, arg);
case XFS_IOC_FD_TO_HANDLE:
case XFS_IOC_PATH_TO_HANDLE:
case XFS_IOC_PATH_TO_FSHANDLE: {
xfs_fsop_handlereq_t hreq;
if (copy_from_user(&hreq, arg, sizeof(hreq)))
return -EFAULT;
return xfs_find_handle(cmd, &hreq);
}
case XFS_IOC_OPEN_BY_HANDLE: {
xfs_fsop_handlereq_t hreq;
if (copy_from_user(&hreq, arg, sizeof(xfs_fsop_handlereq_t)))
return -EFAULT;
return xfs_open_by_handle(filp, &hreq);
}
case XFS_IOC_READLINK_BY_HANDLE: {
xfs_fsop_handlereq_t hreq;
if (copy_from_user(&hreq, arg, sizeof(xfs_fsop_handlereq_t)))
return -EFAULT;
return xfs_readlink_by_handle(filp, &hreq);
}
case XFS_IOC_ATTRLIST_BY_HANDLE:
return xfs_attrlist_by_handle(filp, arg);
case XFS_IOC_ATTRMULTI_BY_HANDLE:
return xfs_attrmulti_by_handle(filp, arg);
case XFS_IOC_SWAPEXT: {
struct xfs_swapext sxp;
if (copy_from_user(&sxp, arg, sizeof(xfs_swapext_t)))
return -EFAULT;
error = mnt_want_write_file(filp);
if (error)
return error;
error = xfs_ioc_swapext(&sxp);
mnt_drop_write_file(filp);
return error;
}
case XFS_IOC_FSCOUNTS: {
xfs_fsop_counts_t out;
xfs_fs_counts(mp, &out);
if (copy_to_user(arg, &out, sizeof(out)))
return -EFAULT;
return 0;
}
case XFS_IOC_SET_RESBLKS: {
xfs_fsop_resblks_t inout;
uint64_t in;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (xfs_is_readonly(mp))
return -EROFS;
if (copy_from_user(&inout, arg, sizeof(inout)))
return -EFAULT;
error = mnt_want_write_file(filp);
if (error)
return error;
/* input parameter is passed in resblks field of structure */
in = inout.resblks;
error = xfs_reserve_blocks(mp, &in, &inout);
mnt_drop_write_file(filp);
if (error)
return error;
if (copy_to_user(arg, &inout, sizeof(inout)))
return -EFAULT;
return 0;
}
case XFS_IOC_GET_RESBLKS: {
xfs_fsop_resblks_t out;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
error = xfs_reserve_blocks(mp, NULL, &out);
if (error)
return error;
if (copy_to_user(arg, &out, sizeof(out)))
return -EFAULT;
return 0;
}
case XFS_IOC_FSGROWFSDATA: {
struct xfs_growfs_data in;
if (copy_from_user(&in, arg, sizeof(in)))
return -EFAULT;
error = mnt_want_write_file(filp);
if (error)
return error;
error = xfs_growfs_data(mp, &in);
mnt_drop_write_file(filp);
return error;
}
case XFS_IOC_FSGROWFSLOG: {
struct xfs_growfs_log in;
if (copy_from_user(&in, arg, sizeof(in)))
return -EFAULT;
error = mnt_want_write_file(filp);
if (error)
return error;
error = xfs_growfs_log(mp, &in);
mnt_drop_write_file(filp);
return error;
}
case XFS_IOC_FSGROWFSRT: {
xfs_growfs_rt_t in;
if (copy_from_user(&in, arg, sizeof(in)))
return -EFAULT;
error = mnt_want_write_file(filp);
if (error)
return error;
error = xfs_growfs_rt(mp, &in);
mnt_drop_write_file(filp);
return error;
}
case XFS_IOC_GOINGDOWN: {
uint32_t in;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (get_user(in, (uint32_t __user *)arg))
return -EFAULT;
return xfs_fs_goingdown(mp, in);
}
case XFS_IOC_ERROR_INJECTION: {
xfs_error_injection_t in;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(&in, arg, sizeof(in)))
return -EFAULT;
return xfs_errortag_add(mp, in.errtag);
}
case XFS_IOC_ERROR_CLEARALL:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return xfs_errortag_clearall(mp);
case XFS_IOC_FREE_EOFBLOCKS: {
struct xfs_fs_eofblocks eofb;
struct xfs_icwalk icw;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (xfs_is_readonly(mp))
return -EROFS;
if (copy_from_user(&eofb, arg, sizeof(eofb)))
return -EFAULT;
error = xfs_fs_eofblocks_from_user(&eofb, &icw);
if (error)
return error;
trace_xfs_ioc_free_eofblocks(mp, &icw, _RET_IP_);
sb_start_write(mp->m_super);
error = xfs_blockgc_free_space(mp, &icw);
sb_end_write(mp->m_super);
return error;
}
default:
return -ENOTTY;
}
}
| linux-master | fs/xfs/xfs_ioctl.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_fs.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_errortag.h"
#include "xfs_error.h"
#include "xfs_sysfs.h"
#include "xfs_inode.h"
#ifdef DEBUG
static unsigned int xfs_errortag_random_default[] = {
XFS_RANDOM_DEFAULT,
XFS_RANDOM_IFLUSH_1,
XFS_RANDOM_IFLUSH_2,
XFS_RANDOM_IFLUSH_3,
XFS_RANDOM_IFLUSH_4,
XFS_RANDOM_IFLUSH_5,
XFS_RANDOM_IFLUSH_6,
XFS_RANDOM_DA_READ_BUF,
XFS_RANDOM_BTREE_CHECK_LBLOCK,
XFS_RANDOM_BTREE_CHECK_SBLOCK,
XFS_RANDOM_ALLOC_READ_AGF,
XFS_RANDOM_IALLOC_READ_AGI,
XFS_RANDOM_ITOBP_INOTOBP,
XFS_RANDOM_IUNLINK,
XFS_RANDOM_IUNLINK_REMOVE,
XFS_RANDOM_DIR_INO_VALIDATE,
XFS_RANDOM_BULKSTAT_READ_CHUNK,
XFS_RANDOM_IODONE_IOERR,
XFS_RANDOM_STRATREAD_IOERR,
XFS_RANDOM_STRATCMPL_IOERR,
XFS_RANDOM_DIOWRITE_IOERR,
XFS_RANDOM_BMAPIFORMAT,
XFS_RANDOM_FREE_EXTENT,
XFS_RANDOM_RMAP_FINISH_ONE,
XFS_RANDOM_REFCOUNT_CONTINUE_UPDATE,
XFS_RANDOM_REFCOUNT_FINISH_ONE,
XFS_RANDOM_BMAP_FINISH_ONE,
XFS_RANDOM_AG_RESV_CRITICAL,
0, /* XFS_RANDOM_DROP_WRITES has been removed */
XFS_RANDOM_LOG_BAD_CRC,
XFS_RANDOM_LOG_ITEM_PIN,
XFS_RANDOM_BUF_LRU_REF,
XFS_RANDOM_FORCE_SCRUB_REPAIR,
XFS_RANDOM_FORCE_SUMMARY_RECALC,
XFS_RANDOM_IUNLINK_FALLBACK,
XFS_RANDOM_BUF_IOERROR,
XFS_RANDOM_REDUCE_MAX_IEXTENTS,
XFS_RANDOM_BMAP_ALLOC_MINLEN_EXTENT,
XFS_RANDOM_AG_RESV_FAIL,
XFS_RANDOM_LARP,
XFS_RANDOM_DA_LEAF_SPLIT,
XFS_RANDOM_ATTR_LEAF_TO_NODE,
XFS_RANDOM_WB_DELAY_MS,
XFS_RANDOM_WRITE_DELAY_MS,
};
struct xfs_errortag_attr {
struct attribute attr;
unsigned int tag;
};
static inline struct xfs_errortag_attr *
to_attr(struct attribute *attr)
{
return container_of(attr, struct xfs_errortag_attr, attr);
}
static inline struct xfs_mount *
to_mp(struct kobject *kobject)
{
struct xfs_kobj *kobj = to_kobj(kobject);
return container_of(kobj, struct xfs_mount, m_errortag_kobj);
}
STATIC ssize_t
xfs_errortag_attr_store(
struct kobject *kobject,
struct attribute *attr,
const char *buf,
size_t count)
{
struct xfs_mount *mp = to_mp(kobject);
struct xfs_errortag_attr *xfs_attr = to_attr(attr);
int ret;
unsigned int val;
if (strcmp(buf, "default") == 0) {
val = xfs_errortag_random_default[xfs_attr->tag];
} else {
ret = kstrtouint(buf, 0, &val);
if (ret)
return ret;
}
ret = xfs_errortag_set(mp, xfs_attr->tag, val);
if (ret)
return ret;
return count;
}
STATIC ssize_t
xfs_errortag_attr_show(
struct kobject *kobject,
struct attribute *attr,
char *buf)
{
struct xfs_mount *mp = to_mp(kobject);
struct xfs_errortag_attr *xfs_attr = to_attr(attr);
return snprintf(buf, PAGE_SIZE, "%u\n",
xfs_errortag_get(mp, xfs_attr->tag));
}
static const struct sysfs_ops xfs_errortag_sysfs_ops = {
.show = xfs_errortag_attr_show,
.store = xfs_errortag_attr_store,
};
#define XFS_ERRORTAG_ATTR_RW(_name, _tag) \
static struct xfs_errortag_attr xfs_errortag_attr_##_name = { \
.attr = {.name = __stringify(_name), \
.mode = VERIFY_OCTAL_PERMISSIONS(S_IWUSR | S_IRUGO) }, \
.tag = (_tag), \
}
#define XFS_ERRORTAG_ATTR_LIST(_name) &xfs_errortag_attr_##_name.attr
XFS_ERRORTAG_ATTR_RW(noerror, XFS_ERRTAG_NOERROR);
XFS_ERRORTAG_ATTR_RW(iflush1, XFS_ERRTAG_IFLUSH_1);
XFS_ERRORTAG_ATTR_RW(iflush2, XFS_ERRTAG_IFLUSH_2);
XFS_ERRORTAG_ATTR_RW(iflush3, XFS_ERRTAG_IFLUSH_3);
XFS_ERRORTAG_ATTR_RW(iflush4, XFS_ERRTAG_IFLUSH_4);
XFS_ERRORTAG_ATTR_RW(iflush5, XFS_ERRTAG_IFLUSH_5);
XFS_ERRORTAG_ATTR_RW(iflush6, XFS_ERRTAG_IFLUSH_6);
XFS_ERRORTAG_ATTR_RW(dareadbuf, XFS_ERRTAG_DA_READ_BUF);
XFS_ERRORTAG_ATTR_RW(btree_chk_lblk, XFS_ERRTAG_BTREE_CHECK_LBLOCK);
XFS_ERRORTAG_ATTR_RW(btree_chk_sblk, XFS_ERRTAG_BTREE_CHECK_SBLOCK);
XFS_ERRORTAG_ATTR_RW(readagf, XFS_ERRTAG_ALLOC_READ_AGF);
XFS_ERRORTAG_ATTR_RW(readagi, XFS_ERRTAG_IALLOC_READ_AGI);
XFS_ERRORTAG_ATTR_RW(itobp, XFS_ERRTAG_ITOBP_INOTOBP);
XFS_ERRORTAG_ATTR_RW(iunlink, XFS_ERRTAG_IUNLINK);
XFS_ERRORTAG_ATTR_RW(iunlinkrm, XFS_ERRTAG_IUNLINK_REMOVE);
XFS_ERRORTAG_ATTR_RW(dirinovalid, XFS_ERRTAG_DIR_INO_VALIDATE);
XFS_ERRORTAG_ATTR_RW(bulkstat, XFS_ERRTAG_BULKSTAT_READ_CHUNK);
XFS_ERRORTAG_ATTR_RW(logiodone, XFS_ERRTAG_IODONE_IOERR);
XFS_ERRORTAG_ATTR_RW(stratread, XFS_ERRTAG_STRATREAD_IOERR);
XFS_ERRORTAG_ATTR_RW(stratcmpl, XFS_ERRTAG_STRATCMPL_IOERR);
XFS_ERRORTAG_ATTR_RW(diowrite, XFS_ERRTAG_DIOWRITE_IOERR);
XFS_ERRORTAG_ATTR_RW(bmapifmt, XFS_ERRTAG_BMAPIFORMAT);
XFS_ERRORTAG_ATTR_RW(free_extent, XFS_ERRTAG_FREE_EXTENT);
XFS_ERRORTAG_ATTR_RW(rmap_finish_one, XFS_ERRTAG_RMAP_FINISH_ONE);
XFS_ERRORTAG_ATTR_RW(refcount_continue_update, XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE);
XFS_ERRORTAG_ATTR_RW(refcount_finish_one, XFS_ERRTAG_REFCOUNT_FINISH_ONE);
XFS_ERRORTAG_ATTR_RW(bmap_finish_one, XFS_ERRTAG_BMAP_FINISH_ONE);
XFS_ERRORTAG_ATTR_RW(ag_resv_critical, XFS_ERRTAG_AG_RESV_CRITICAL);
XFS_ERRORTAG_ATTR_RW(log_bad_crc, XFS_ERRTAG_LOG_BAD_CRC);
XFS_ERRORTAG_ATTR_RW(log_item_pin, XFS_ERRTAG_LOG_ITEM_PIN);
XFS_ERRORTAG_ATTR_RW(buf_lru_ref, XFS_ERRTAG_BUF_LRU_REF);
XFS_ERRORTAG_ATTR_RW(force_repair, XFS_ERRTAG_FORCE_SCRUB_REPAIR);
XFS_ERRORTAG_ATTR_RW(bad_summary, XFS_ERRTAG_FORCE_SUMMARY_RECALC);
XFS_ERRORTAG_ATTR_RW(iunlink_fallback, XFS_ERRTAG_IUNLINK_FALLBACK);
XFS_ERRORTAG_ATTR_RW(buf_ioerror, XFS_ERRTAG_BUF_IOERROR);
XFS_ERRORTAG_ATTR_RW(reduce_max_iextents, XFS_ERRTAG_REDUCE_MAX_IEXTENTS);
XFS_ERRORTAG_ATTR_RW(bmap_alloc_minlen_extent, XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT);
XFS_ERRORTAG_ATTR_RW(ag_resv_fail, XFS_ERRTAG_AG_RESV_FAIL);
XFS_ERRORTAG_ATTR_RW(larp, XFS_ERRTAG_LARP);
XFS_ERRORTAG_ATTR_RW(da_leaf_split, XFS_ERRTAG_DA_LEAF_SPLIT);
XFS_ERRORTAG_ATTR_RW(attr_leaf_to_node, XFS_ERRTAG_ATTR_LEAF_TO_NODE);
XFS_ERRORTAG_ATTR_RW(wb_delay_ms, XFS_ERRTAG_WB_DELAY_MS);
XFS_ERRORTAG_ATTR_RW(write_delay_ms, XFS_ERRTAG_WRITE_DELAY_MS);
static struct attribute *xfs_errortag_attrs[] = {
XFS_ERRORTAG_ATTR_LIST(noerror),
XFS_ERRORTAG_ATTR_LIST(iflush1),
XFS_ERRORTAG_ATTR_LIST(iflush2),
XFS_ERRORTAG_ATTR_LIST(iflush3),
XFS_ERRORTAG_ATTR_LIST(iflush4),
XFS_ERRORTAG_ATTR_LIST(iflush5),
XFS_ERRORTAG_ATTR_LIST(iflush6),
XFS_ERRORTAG_ATTR_LIST(dareadbuf),
XFS_ERRORTAG_ATTR_LIST(btree_chk_lblk),
XFS_ERRORTAG_ATTR_LIST(btree_chk_sblk),
XFS_ERRORTAG_ATTR_LIST(readagf),
XFS_ERRORTAG_ATTR_LIST(readagi),
XFS_ERRORTAG_ATTR_LIST(itobp),
XFS_ERRORTAG_ATTR_LIST(iunlink),
XFS_ERRORTAG_ATTR_LIST(iunlinkrm),
XFS_ERRORTAG_ATTR_LIST(dirinovalid),
XFS_ERRORTAG_ATTR_LIST(bulkstat),
XFS_ERRORTAG_ATTR_LIST(logiodone),
XFS_ERRORTAG_ATTR_LIST(stratread),
XFS_ERRORTAG_ATTR_LIST(stratcmpl),
XFS_ERRORTAG_ATTR_LIST(diowrite),
XFS_ERRORTAG_ATTR_LIST(bmapifmt),
XFS_ERRORTAG_ATTR_LIST(free_extent),
XFS_ERRORTAG_ATTR_LIST(rmap_finish_one),
XFS_ERRORTAG_ATTR_LIST(refcount_continue_update),
XFS_ERRORTAG_ATTR_LIST(refcount_finish_one),
XFS_ERRORTAG_ATTR_LIST(bmap_finish_one),
XFS_ERRORTAG_ATTR_LIST(ag_resv_critical),
XFS_ERRORTAG_ATTR_LIST(log_bad_crc),
XFS_ERRORTAG_ATTR_LIST(log_item_pin),
XFS_ERRORTAG_ATTR_LIST(buf_lru_ref),
XFS_ERRORTAG_ATTR_LIST(force_repair),
XFS_ERRORTAG_ATTR_LIST(bad_summary),
XFS_ERRORTAG_ATTR_LIST(iunlink_fallback),
XFS_ERRORTAG_ATTR_LIST(buf_ioerror),
XFS_ERRORTAG_ATTR_LIST(reduce_max_iextents),
XFS_ERRORTAG_ATTR_LIST(bmap_alloc_minlen_extent),
XFS_ERRORTAG_ATTR_LIST(ag_resv_fail),
XFS_ERRORTAG_ATTR_LIST(larp),
XFS_ERRORTAG_ATTR_LIST(da_leaf_split),
XFS_ERRORTAG_ATTR_LIST(attr_leaf_to_node),
XFS_ERRORTAG_ATTR_LIST(wb_delay_ms),
XFS_ERRORTAG_ATTR_LIST(write_delay_ms),
NULL,
};
ATTRIBUTE_GROUPS(xfs_errortag);
static const struct kobj_type xfs_errortag_ktype = {
.release = xfs_sysfs_release,
.sysfs_ops = &xfs_errortag_sysfs_ops,
.default_groups = xfs_errortag_groups,
};
int
xfs_errortag_init(
struct xfs_mount *mp)
{
int ret;
mp->m_errortag = kmem_zalloc(sizeof(unsigned int) * XFS_ERRTAG_MAX,
KM_MAYFAIL);
if (!mp->m_errortag)
return -ENOMEM;
ret = xfs_sysfs_init(&mp->m_errortag_kobj, &xfs_errortag_ktype,
&mp->m_kobj, "errortag");
if (ret)
kmem_free(mp->m_errortag);
return ret;
}
void
xfs_errortag_del(
struct xfs_mount *mp)
{
xfs_sysfs_del(&mp->m_errortag_kobj);
kmem_free(mp->m_errortag);
}
static bool
xfs_errortag_valid(
unsigned int error_tag)
{
if (error_tag >= XFS_ERRTAG_MAX)
return false;
/* Error out removed injection types */
if (error_tag == XFS_ERRTAG_DROP_WRITES)
return false;
return true;
}
bool
xfs_errortag_enabled(
struct xfs_mount *mp,
unsigned int tag)
{
if (!mp->m_errortag)
return false;
if (!xfs_errortag_valid(tag))
return false;
return mp->m_errortag[tag] != 0;
}
bool
xfs_errortag_test(
struct xfs_mount *mp,
const char *expression,
const char *file,
int line,
unsigned int error_tag)
{
unsigned int randfactor;
/*
* To be able to use error injection anywhere, we need to ensure error
* injection mechanism is already initialized.
*
* Code paths like I/O completion can be called before the
* initialization is complete, but be able to inject errors in such
* places is still useful.
*/
if (!mp->m_errortag)
return false;
if (!xfs_errortag_valid(error_tag))
return false;
randfactor = mp->m_errortag[error_tag];
if (!randfactor || get_random_u32_below(randfactor))
return false;
xfs_warn_ratelimited(mp,
"Injecting error (%s) at file %s, line %d, on filesystem \"%s\"",
expression, file, line, mp->m_super->s_id);
return true;
}
int
xfs_errortag_get(
struct xfs_mount *mp,
unsigned int error_tag)
{
if (!xfs_errortag_valid(error_tag))
return -EINVAL;
return mp->m_errortag[error_tag];
}
int
xfs_errortag_set(
struct xfs_mount *mp,
unsigned int error_tag,
unsigned int tag_value)
{
if (!xfs_errortag_valid(error_tag))
return -EINVAL;
mp->m_errortag[error_tag] = tag_value;
return 0;
}
int
xfs_errortag_add(
struct xfs_mount *mp,
unsigned int error_tag)
{
BUILD_BUG_ON(ARRAY_SIZE(xfs_errortag_random_default) != XFS_ERRTAG_MAX);
if (!xfs_errortag_valid(error_tag))
return -EINVAL;
return xfs_errortag_set(mp, error_tag,
xfs_errortag_random_default[error_tag]);
}
int
xfs_errortag_clearall(
struct xfs_mount *mp)
{
memset(mp->m_errortag, 0, sizeof(unsigned int) * XFS_ERRTAG_MAX);
return 0;
}
#endif /* DEBUG */
void
xfs_error_report(
const char *tag,
int level,
struct xfs_mount *mp,
const char *filename,
int linenum,
xfs_failaddr_t failaddr)
{
if (level <= xfs_error_level) {
xfs_alert_tag(mp, XFS_PTAG_ERROR_REPORT,
"Internal error %s at line %d of file %s. Caller %pS",
tag, linenum, filename, failaddr);
xfs_stack_trace();
}
}
void
xfs_corruption_error(
const char *tag,
int level,
struct xfs_mount *mp,
const void *buf,
size_t bufsize,
const char *filename,
int linenum,
xfs_failaddr_t failaddr)
{
if (buf && level <= xfs_error_level)
xfs_hex_dump(buf, bufsize);
xfs_error_report(tag, level, mp, filename, linenum, failaddr);
xfs_alert(mp, "Corruption detected. Unmount and run xfs_repair");
}
/*
* Complain about the kinds of metadata corruption that we can't detect from a
* verifier, such as incorrect inter-block relationship data. Does not set
* bp->b_error.
*
* Call xfs_buf_mark_corrupt, not this function.
*/
void
xfs_buf_corruption_error(
struct xfs_buf *bp,
xfs_failaddr_t fa)
{
struct xfs_mount *mp = bp->b_mount;
xfs_alert_tag(mp, XFS_PTAG_VERIFIER_ERROR,
"Metadata corruption detected at %pS, %s block 0x%llx",
fa, bp->b_ops->name, xfs_buf_daddr(bp));
xfs_alert(mp, "Unmount and run xfs_repair");
if (xfs_error_level >= XFS_ERRLEVEL_HIGH)
xfs_stack_trace();
}
/*
* Warnings specifically for verifier errors. Differentiate CRC vs. invalid
* values, and omit the stack trace unless the error level is tuned high.
*/
void
xfs_buf_verifier_error(
struct xfs_buf *bp,
int error,
const char *name,
const void *buf,
size_t bufsz,
xfs_failaddr_t failaddr)
{
struct xfs_mount *mp = bp->b_mount;
xfs_failaddr_t fa;
int sz;
fa = failaddr ? failaddr : __return_address;
__xfs_buf_ioerror(bp, error, fa);
xfs_alert_tag(mp, XFS_PTAG_VERIFIER_ERROR,
"Metadata %s detected at %pS, %s block 0x%llx %s",
bp->b_error == -EFSBADCRC ? "CRC error" : "corruption",
fa, bp->b_ops->name, xfs_buf_daddr(bp), name);
xfs_alert(mp, "Unmount and run xfs_repair");
if (xfs_error_level >= XFS_ERRLEVEL_LOW) {
sz = min_t(size_t, XFS_CORRUPTION_DUMP_LEN, bufsz);
xfs_alert(mp, "First %d bytes of corrupted metadata buffer:",
sz);
xfs_hex_dump(buf, sz);
}
if (xfs_error_level >= XFS_ERRLEVEL_HIGH)
xfs_stack_trace();
}
/*
* Warnings specifically for verifier errors. Differentiate CRC vs. invalid
* values, and omit the stack trace unless the error level is tuned high.
*/
void
xfs_verifier_error(
struct xfs_buf *bp,
int error,
xfs_failaddr_t failaddr)
{
return xfs_buf_verifier_error(bp, error, "", xfs_buf_offset(bp, 0),
XFS_CORRUPTION_DUMP_LEN, failaddr);
}
/*
* Warnings for inode corruption problems. Don't bother with the stack
* trace unless the error level is turned up high.
*/
void
xfs_inode_verifier_error(
struct xfs_inode *ip,
int error,
const char *name,
const void *buf,
size_t bufsz,
xfs_failaddr_t failaddr)
{
struct xfs_mount *mp = ip->i_mount;
xfs_failaddr_t fa;
int sz;
fa = failaddr ? failaddr : __return_address;
xfs_alert(mp, "Metadata %s detected at %pS, inode 0x%llx %s",
error == -EFSBADCRC ? "CRC error" : "corruption",
fa, ip->i_ino, name);
xfs_alert(mp, "Unmount and run xfs_repair");
if (buf && xfs_error_level >= XFS_ERRLEVEL_LOW) {
sz = min_t(size_t, XFS_CORRUPTION_DUMP_LEN, bufsz);
xfs_alert(mp, "First %d bytes of corrupted metadata buffer:",
sz);
xfs_hex_dump(buf, sz);
}
if (xfs_error_level >= XFS_ERRLEVEL_HIGH)
xfs_stack_trace();
}
| linux-master | fs/xfs/xfs_error.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_errortag.h"
#include "xfs_error.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_trace.h"
#include "xfs_sysfs.h"
#include "xfs_sb.h"
#include "xfs_health.h"
struct kmem_cache *xfs_log_ticket_cache;
/* Local miscellaneous function prototypes */
STATIC struct xlog *
xlog_alloc_log(
struct xfs_mount *mp,
struct xfs_buftarg *log_target,
xfs_daddr_t blk_offset,
int num_bblks);
STATIC int
xlog_space_left(
struct xlog *log,
atomic64_t *head);
STATIC void
xlog_dealloc_log(
struct xlog *log);
/* local state machine functions */
STATIC void xlog_state_done_syncing(
struct xlog_in_core *iclog);
STATIC void xlog_state_do_callback(
struct xlog *log);
STATIC int
xlog_state_get_iclog_space(
struct xlog *log,
int len,
struct xlog_in_core **iclog,
struct xlog_ticket *ticket,
int *logoffsetp);
STATIC void
xlog_grant_push_ail(
struct xlog *log,
int need_bytes);
STATIC void
xlog_sync(
struct xlog *log,
struct xlog_in_core *iclog,
struct xlog_ticket *ticket);
#if defined(DEBUG)
STATIC void
xlog_verify_grant_tail(
struct xlog *log);
STATIC void
xlog_verify_iclog(
struct xlog *log,
struct xlog_in_core *iclog,
int count);
STATIC void
xlog_verify_tail_lsn(
struct xlog *log,
struct xlog_in_core *iclog);
#else
#define xlog_verify_grant_tail(a)
#define xlog_verify_iclog(a,b,c)
#define xlog_verify_tail_lsn(a,b)
#endif
STATIC int
xlog_iclogs_empty(
struct xlog *log);
static int
xfs_log_cover(struct xfs_mount *);
/*
* We need to make sure the buffer pointer returned is naturally aligned for the
* biggest basic data type we put into it. We have already accounted for this
* padding when sizing the buffer.
*
* However, this padding does not get written into the log, and hence we have to
* track the space used by the log vectors separately to prevent log space hangs
* due to inaccurate accounting (i.e. a leak) of the used log space through the
* CIL context ticket.
*
* We also add space for the xlog_op_header that describes this region in the
* log. This prepends the data region we return to the caller to copy their data
* into, so do all the static initialisation of the ophdr now. Because the ophdr
* is not 8 byte aligned, we have to be careful to ensure that we align the
* start of the buffer such that the region we return to the call is 8 byte
* aligned and packed against the tail of the ophdr.
*/
void *
xlog_prepare_iovec(
struct xfs_log_vec *lv,
struct xfs_log_iovec **vecp,
uint type)
{
struct xfs_log_iovec *vec = *vecp;
struct xlog_op_header *oph;
uint32_t len;
void *buf;
if (vec) {
ASSERT(vec - lv->lv_iovecp < lv->lv_niovecs);
vec++;
} else {
vec = &lv->lv_iovecp[0];
}
len = lv->lv_buf_len + sizeof(struct xlog_op_header);
if (!IS_ALIGNED(len, sizeof(uint64_t))) {
lv->lv_buf_len = round_up(len, sizeof(uint64_t)) -
sizeof(struct xlog_op_header);
}
vec->i_type = type;
vec->i_addr = lv->lv_buf + lv->lv_buf_len;
oph = vec->i_addr;
oph->oh_clientid = XFS_TRANSACTION;
oph->oh_res2 = 0;
oph->oh_flags = 0;
buf = vec->i_addr + sizeof(struct xlog_op_header);
ASSERT(IS_ALIGNED((unsigned long)buf, sizeof(uint64_t)));
*vecp = vec;
return buf;
}
static void
xlog_grant_sub_space(
struct xlog *log,
atomic64_t *head,
int bytes)
{
int64_t head_val = atomic64_read(head);
int64_t new, old;
do {
int cycle, space;
xlog_crack_grant_head_val(head_val, &cycle, &space);
space -= bytes;
if (space < 0) {
space += log->l_logsize;
cycle--;
}
old = head_val;
new = xlog_assign_grant_head_val(cycle, space);
head_val = atomic64_cmpxchg(head, old, new);
} while (head_val != old);
}
static void
xlog_grant_add_space(
struct xlog *log,
atomic64_t *head,
int bytes)
{
int64_t head_val = atomic64_read(head);
int64_t new, old;
do {
int tmp;
int cycle, space;
xlog_crack_grant_head_val(head_val, &cycle, &space);
tmp = log->l_logsize - space;
if (tmp > bytes)
space += bytes;
else {
space = bytes - tmp;
cycle++;
}
old = head_val;
new = xlog_assign_grant_head_val(cycle, space);
head_val = atomic64_cmpxchg(head, old, new);
} while (head_val != old);
}
STATIC void
xlog_grant_head_init(
struct xlog_grant_head *head)
{
xlog_assign_grant_head(&head->grant, 1, 0);
INIT_LIST_HEAD(&head->waiters);
spin_lock_init(&head->lock);
}
STATIC void
xlog_grant_head_wake_all(
struct xlog_grant_head *head)
{
struct xlog_ticket *tic;
spin_lock(&head->lock);
list_for_each_entry(tic, &head->waiters, t_queue)
wake_up_process(tic->t_task);
spin_unlock(&head->lock);
}
static inline int
xlog_ticket_reservation(
struct xlog *log,
struct xlog_grant_head *head,
struct xlog_ticket *tic)
{
if (head == &log->l_write_head) {
ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
return tic->t_unit_res;
}
if (tic->t_flags & XLOG_TIC_PERM_RESERV)
return tic->t_unit_res * tic->t_cnt;
return tic->t_unit_res;
}
STATIC bool
xlog_grant_head_wake(
struct xlog *log,
struct xlog_grant_head *head,
int *free_bytes)
{
struct xlog_ticket *tic;
int need_bytes;
bool woken_task = false;
list_for_each_entry(tic, &head->waiters, t_queue) {
/*
* There is a chance that the size of the CIL checkpoints in
* progress at the last AIL push target calculation resulted in
* limiting the target to the log head (l_last_sync_lsn) at the
* time. This may not reflect where the log head is now as the
* CIL checkpoints may have completed.
*
* Hence when we are woken here, it may be that the head of the
* log that has moved rather than the tail. As the tail didn't
* move, there still won't be space available for the
* reservation we require. However, if the AIL has already
* pushed to the target defined by the old log head location, we
* will hang here waiting for something else to update the AIL
* push target.
*
* Therefore, if there isn't space to wake the first waiter on
* the grant head, we need to push the AIL again to ensure the
* target reflects both the current log tail and log head
* position before we wait for the tail to move again.
*/
need_bytes = xlog_ticket_reservation(log, head, tic);
if (*free_bytes < need_bytes) {
if (!woken_task)
xlog_grant_push_ail(log, need_bytes);
return false;
}
*free_bytes -= need_bytes;
trace_xfs_log_grant_wake_up(log, tic);
wake_up_process(tic->t_task);
woken_task = true;
}
return true;
}
STATIC int
xlog_grant_head_wait(
struct xlog *log,
struct xlog_grant_head *head,
struct xlog_ticket *tic,
int need_bytes) __releases(&head->lock)
__acquires(&head->lock)
{
list_add_tail(&tic->t_queue, &head->waiters);
do {
if (xlog_is_shutdown(log))
goto shutdown;
xlog_grant_push_ail(log, need_bytes);
__set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock(&head->lock);
XFS_STATS_INC(log->l_mp, xs_sleep_logspace);
trace_xfs_log_grant_sleep(log, tic);
schedule();
trace_xfs_log_grant_wake(log, tic);
spin_lock(&head->lock);
if (xlog_is_shutdown(log))
goto shutdown;
} while (xlog_space_left(log, &head->grant) < need_bytes);
list_del_init(&tic->t_queue);
return 0;
shutdown:
list_del_init(&tic->t_queue);
return -EIO;
}
/*
* Atomically get the log space required for a log ticket.
*
* Once a ticket gets put onto head->waiters, it will only return after the
* needed reservation is satisfied.
*
* This function is structured so that it has a lock free fast path. This is
* necessary because every new transaction reservation will come through this
* path. Hence any lock will be globally hot if we take it unconditionally on
* every pass.
*
* As tickets are only ever moved on and off head->waiters under head->lock, we
* only need to take that lock if we are going to add the ticket to the queue
* and sleep. We can avoid taking the lock if the ticket was never added to
* head->waiters because the t_queue list head will be empty and we hold the
* only reference to it so it can safely be checked unlocked.
*/
STATIC int
xlog_grant_head_check(
struct xlog *log,
struct xlog_grant_head *head,
struct xlog_ticket *tic,
int *need_bytes)
{
int free_bytes;
int error = 0;
ASSERT(!xlog_in_recovery(log));
/*
* If there are other waiters on the queue then give them a chance at
* logspace before us. Wake up the first waiters, if we do not wake
* up all the waiters then go to sleep waiting for more free space,
* otherwise try to get some space for this transaction.
*/
*need_bytes = xlog_ticket_reservation(log, head, tic);
free_bytes = xlog_space_left(log, &head->grant);
if (!list_empty_careful(&head->waiters)) {
spin_lock(&head->lock);
if (!xlog_grant_head_wake(log, head, &free_bytes) ||
free_bytes < *need_bytes) {
error = xlog_grant_head_wait(log, head, tic,
*need_bytes);
}
spin_unlock(&head->lock);
} else if (free_bytes < *need_bytes) {
spin_lock(&head->lock);
error = xlog_grant_head_wait(log, head, tic, *need_bytes);
spin_unlock(&head->lock);
}
return error;
}
bool
xfs_log_writable(
struct xfs_mount *mp)
{
/*
* Do not write to the log on norecovery mounts, if the data or log
* devices are read-only, or if the filesystem is shutdown. Read-only
* mounts allow internal writes for log recovery and unmount purposes,
* so don't restrict that case.
*/
if (xfs_has_norecovery(mp))
return false;
if (xfs_readonly_buftarg(mp->m_ddev_targp))
return false;
if (xfs_readonly_buftarg(mp->m_log->l_targ))
return false;
if (xlog_is_shutdown(mp->m_log))
return false;
return true;
}
/*
* Replenish the byte reservation required by moving the grant write head.
*/
int
xfs_log_regrant(
struct xfs_mount *mp,
struct xlog_ticket *tic)
{
struct xlog *log = mp->m_log;
int need_bytes;
int error = 0;
if (xlog_is_shutdown(log))
return -EIO;
XFS_STATS_INC(mp, xs_try_logspace);
/*
* This is a new transaction on the ticket, so we need to change the
* transaction ID so that the next transaction has a different TID in
* the log. Just add one to the existing tid so that we can see chains
* of rolling transactions in the log easily.
*/
tic->t_tid++;
xlog_grant_push_ail(log, tic->t_unit_res);
tic->t_curr_res = tic->t_unit_res;
if (tic->t_cnt > 0)
return 0;
trace_xfs_log_regrant(log, tic);
error = xlog_grant_head_check(log, &log->l_write_head, tic,
&need_bytes);
if (error)
goto out_error;
xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
trace_xfs_log_regrant_exit(log, tic);
xlog_verify_grant_tail(log);
return 0;
out_error:
/*
* If we are failing, make sure the ticket doesn't have any current
* reservations. We don't want to add this back when the ticket/
* transaction gets cancelled.
*/
tic->t_curr_res = 0;
tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
return error;
}
/*
* Reserve log space and return a ticket corresponding to the reservation.
*
* Each reservation is going to reserve extra space for a log record header.
* When writes happen to the on-disk log, we don't subtract the length of the
* log record header from any reservation. By wasting space in each
* reservation, we prevent over allocation problems.
*/
int
xfs_log_reserve(
struct xfs_mount *mp,
int unit_bytes,
int cnt,
struct xlog_ticket **ticp,
bool permanent)
{
struct xlog *log = mp->m_log;
struct xlog_ticket *tic;
int need_bytes;
int error = 0;
if (xlog_is_shutdown(log))
return -EIO;
XFS_STATS_INC(mp, xs_try_logspace);
ASSERT(*ticp == NULL);
tic = xlog_ticket_alloc(log, unit_bytes, cnt, permanent);
*ticp = tic;
xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
: tic->t_unit_res);
trace_xfs_log_reserve(log, tic);
error = xlog_grant_head_check(log, &log->l_reserve_head, tic,
&need_bytes);
if (error)
goto out_error;
xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes);
xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes);
trace_xfs_log_reserve_exit(log, tic);
xlog_verify_grant_tail(log);
return 0;
out_error:
/*
* If we are failing, make sure the ticket doesn't have any current
* reservations. We don't want to add this back when the ticket/
* transaction gets cancelled.
*/
tic->t_curr_res = 0;
tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
return error;
}
/*
* Run all the pending iclog callbacks and wake log force waiters and iclog
* space waiters so they can process the newly set shutdown state. We really
* don't care what order we process callbacks here because the log is shut down
* and so state cannot change on disk anymore. However, we cannot wake waiters
* until the callbacks have been processed because we may be in unmount and
* we must ensure that all AIL operations the callbacks perform have completed
* before we tear down the AIL.
*
* We avoid processing actively referenced iclogs so that we don't run callbacks
* while the iclog owner might still be preparing the iclog for IO submssion.
* These will be caught by xlog_state_iclog_release() and call this function
* again to process any callbacks that may have been added to that iclog.
*/
static void
xlog_state_shutdown_callbacks(
struct xlog *log)
{
struct xlog_in_core *iclog;
LIST_HEAD(cb_list);
iclog = log->l_iclog;
do {
if (atomic_read(&iclog->ic_refcnt)) {
/* Reference holder will re-run iclog callbacks. */
continue;
}
list_splice_init(&iclog->ic_callbacks, &cb_list);
spin_unlock(&log->l_icloglock);
xlog_cil_process_committed(&cb_list);
spin_lock(&log->l_icloglock);
wake_up_all(&iclog->ic_write_wait);
wake_up_all(&iclog->ic_force_wait);
} while ((iclog = iclog->ic_next) != log->l_iclog);
wake_up_all(&log->l_flush_wait);
}
/*
* Flush iclog to disk if this is the last reference to the given iclog and the
* it is in the WANT_SYNC state.
*
* If XLOG_ICL_NEED_FUA is already set on the iclog, we need to ensure that the
* log tail is updated correctly. NEED_FUA indicates that the iclog will be
* written to stable storage, and implies that a commit record is contained
* within the iclog. We need to ensure that the log tail does not move beyond
* the tail that the first commit record in the iclog ordered against, otherwise
* correct recovery of that checkpoint becomes dependent on future operations
* performed on this iclog.
*
* Hence if NEED_FUA is set and the current iclog tail lsn is empty, write the
* current tail into iclog. Once the iclog tail is set, future operations must
* not modify it, otherwise they potentially violate ordering constraints for
* the checkpoint commit that wrote the initial tail lsn value. The tail lsn in
* the iclog will get zeroed on activation of the iclog after sync, so we
* always capture the tail lsn on the iclog on the first NEED_FUA release
* regardless of the number of active reference counts on this iclog.
*/
int
xlog_state_release_iclog(
struct xlog *log,
struct xlog_in_core *iclog,
struct xlog_ticket *ticket)
{
xfs_lsn_t tail_lsn;
bool last_ref;
lockdep_assert_held(&log->l_icloglock);
trace_xlog_iclog_release(iclog, _RET_IP_);
/*
* Grabbing the current log tail needs to be atomic w.r.t. the writing
* of the tail LSN into the iclog so we guarantee that the log tail does
* not move between the first time we know that the iclog needs to be
* made stable and when we eventually submit it.
*/
if ((iclog->ic_state == XLOG_STATE_WANT_SYNC ||
(iclog->ic_flags & XLOG_ICL_NEED_FUA)) &&
!iclog->ic_header.h_tail_lsn) {
tail_lsn = xlog_assign_tail_lsn(log->l_mp);
iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn);
}
last_ref = atomic_dec_and_test(&iclog->ic_refcnt);
if (xlog_is_shutdown(log)) {
/*
* If there are no more references to this iclog, process the
* pending iclog callbacks that were waiting on the release of
* this iclog.
*/
if (last_ref)
xlog_state_shutdown_callbacks(log);
return -EIO;
}
if (!last_ref)
return 0;
if (iclog->ic_state != XLOG_STATE_WANT_SYNC) {
ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
return 0;
}
iclog->ic_state = XLOG_STATE_SYNCING;
xlog_verify_tail_lsn(log, iclog);
trace_xlog_iclog_syncing(iclog, _RET_IP_);
spin_unlock(&log->l_icloglock);
xlog_sync(log, iclog, ticket);
spin_lock(&log->l_icloglock);
return 0;
}
/*
* Mount a log filesystem
*
* mp - ubiquitous xfs mount point structure
* log_target - buftarg of on-disk log device
* blk_offset - Start block # where block size is 512 bytes (BBSIZE)
* num_bblocks - Number of BBSIZE blocks in on-disk log
*
* Return error or zero.
*/
int
xfs_log_mount(
xfs_mount_t *mp,
xfs_buftarg_t *log_target,
xfs_daddr_t blk_offset,
int num_bblks)
{
struct xlog *log;
int error = 0;
int min_logfsbs;
if (!xfs_has_norecovery(mp)) {
xfs_notice(mp, "Mounting V%d Filesystem %pU",
XFS_SB_VERSION_NUM(&mp->m_sb),
&mp->m_sb.sb_uuid);
} else {
xfs_notice(mp,
"Mounting V%d filesystem %pU in no-recovery mode. Filesystem will be inconsistent.",
XFS_SB_VERSION_NUM(&mp->m_sb),
&mp->m_sb.sb_uuid);
ASSERT(xfs_is_readonly(mp));
}
log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
if (IS_ERR(log)) {
error = PTR_ERR(log);
goto out;
}
mp->m_log = log;
/*
* Now that we have set up the log and it's internal geometry
* parameters, we can validate the given log space and drop a critical
* message via syslog if the log size is too small. A log that is too
* small can lead to unexpected situations in transaction log space
* reservation stage. The superblock verifier has already validated all
* the other log geometry constraints, so we don't have to check those
* here.
*
* Note: For v4 filesystems, we can't just reject the mount if the
* validation fails. This would mean that people would have to
* downgrade their kernel just to remedy the situation as there is no
* way to grow the log (short of black magic surgery with xfs_db).
*
* We can, however, reject mounts for V5 format filesystems, as the
* mkfs binary being used to make the filesystem should never create a
* filesystem with a log that is too small.
*/
min_logfsbs = xfs_log_calc_minimum_size(mp);
if (mp->m_sb.sb_logblocks < min_logfsbs) {
xfs_warn(mp,
"Log size %d blocks too small, minimum size is %d blocks",
mp->m_sb.sb_logblocks, min_logfsbs);
/*
* Log check errors are always fatal on v5; or whenever bad
* metadata leads to a crash.
*/
if (xfs_has_crc(mp)) {
xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
ASSERT(0);
error = -EINVAL;
goto out_free_log;
}
xfs_crit(mp, "Log size out of supported range.");
xfs_crit(mp,
"Continuing onwards, but if log hangs are experienced then please report this message in the bug report.");
}
/*
* Initialize the AIL now we have a log.
*/
error = xfs_trans_ail_init(mp);
if (error) {
xfs_warn(mp, "AIL initialisation failed: error %d", error);
goto out_free_log;
}
log->l_ailp = mp->m_ail;
/*
* skip log recovery on a norecovery mount. pretend it all
* just worked.
*/
if (!xfs_has_norecovery(mp)) {
error = xlog_recover(log);
if (error) {
xfs_warn(mp, "log mount/recovery failed: error %d",
error);
xlog_recover_cancel(log);
goto out_destroy_ail;
}
}
error = xfs_sysfs_init(&log->l_kobj, &xfs_log_ktype, &mp->m_kobj,
"log");
if (error)
goto out_destroy_ail;
/* Normal transactions can now occur */
clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
/*
* Now the log has been fully initialised and we know were our
* space grant counters are, we can initialise the permanent ticket
* needed for delayed logging to work.
*/
xlog_cil_init_post_recovery(log);
return 0;
out_destroy_ail:
xfs_trans_ail_destroy(mp);
out_free_log:
xlog_dealloc_log(log);
out:
return error;
}
/*
* Finish the recovery of the file system. This is separate from the
* xfs_log_mount() call, because it depends on the code in xfs_mountfs() to read
* in the root and real-time bitmap inodes between calling xfs_log_mount() and
* here.
*
* If we finish recovery successfully, start the background log work. If we are
* not doing recovery, then we have a RO filesystem and we don't need to start
* it.
*/
int
xfs_log_mount_finish(
struct xfs_mount *mp)
{
struct xlog *log = mp->m_log;
int error = 0;
if (xfs_has_norecovery(mp)) {
ASSERT(xfs_is_readonly(mp));
return 0;
}
/*
* During the second phase of log recovery, we need iget and
* iput to behave like they do for an active filesystem.
* xfs_fs_drop_inode needs to be able to prevent the deletion
* of inodes before we're done replaying log items on those
* inodes. Turn it off immediately after recovery finishes
* so that we don't leak the quota inodes if subsequent mount
* activities fail.
*
* We let all inodes involved in redo item processing end up on
* the LRU instead of being evicted immediately so that if we do
* something to an unlinked inode, the irele won't cause
* premature truncation and freeing of the inode, which results
* in log recovery failure. We have to evict the unreferenced
* lru inodes after clearing SB_ACTIVE because we don't
* otherwise clean up the lru if there's a subsequent failure in
* xfs_mountfs, which leads to us leaking the inodes if nothing
* else (e.g. quotacheck) references the inodes before the
* mount failure occurs.
*/
mp->m_super->s_flags |= SB_ACTIVE;
xfs_log_work_queue(mp);
if (xlog_recovery_needed(log))
error = xlog_recover_finish(log);
mp->m_super->s_flags &= ~SB_ACTIVE;
evict_inodes(mp->m_super);
/*
* Drain the buffer LRU after log recovery. This is required for v4
* filesystems to avoid leaving around buffers with NULL verifier ops,
* but we do it unconditionally to make sure we're always in a clean
* cache state after mount.
*
* Don't push in the error case because the AIL may have pending intents
* that aren't removed until recovery is cancelled.
*/
if (xlog_recovery_needed(log)) {
if (!error) {
xfs_log_force(mp, XFS_LOG_SYNC);
xfs_ail_push_all_sync(mp->m_ail);
}
xfs_notice(mp, "Ending recovery (logdev: %s)",
mp->m_logname ? mp->m_logname : "internal");
} else {
xfs_info(mp, "Ending clean mount");
}
xfs_buftarg_drain(mp->m_ddev_targp);
clear_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
/* Make sure the log is dead if we're returning failure. */
ASSERT(!error || xlog_is_shutdown(log));
return error;
}
/*
* The mount has failed. Cancel the recovery if it hasn't completed and destroy
* the log.
*/
void
xfs_log_mount_cancel(
struct xfs_mount *mp)
{
xlog_recover_cancel(mp->m_log);
xfs_log_unmount(mp);
}
/*
* Flush out the iclog to disk ensuring that device caches are flushed and
* the iclog hits stable storage before any completion waiters are woken.
*/
static inline int
xlog_force_iclog(
struct xlog_in_core *iclog)
{
atomic_inc(&iclog->ic_refcnt);
iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
if (iclog->ic_state == XLOG_STATE_ACTIVE)
xlog_state_switch_iclogs(iclog->ic_log, iclog, 0);
return xlog_state_release_iclog(iclog->ic_log, iclog, NULL);
}
/*
* Cycle all the iclogbuf locks to make sure all log IO completion
* is done before we tear down these buffers.
*/
static void
xlog_wait_iclog_completion(struct xlog *log)
{
int i;
struct xlog_in_core *iclog = log->l_iclog;
for (i = 0; i < log->l_iclog_bufs; i++) {
down(&iclog->ic_sema);
up(&iclog->ic_sema);
iclog = iclog->ic_next;
}
}
/*
* Wait for the iclog and all prior iclogs to be written disk as required by the
* log force state machine. Waiting on ic_force_wait ensures iclog completions
* have been ordered and callbacks run before we are woken here, hence
* guaranteeing that all the iclogs up to this one are on stable storage.
*/
int
xlog_wait_on_iclog(
struct xlog_in_core *iclog)
__releases(iclog->ic_log->l_icloglock)
{
struct xlog *log = iclog->ic_log;
trace_xlog_iclog_wait_on(iclog, _RET_IP_);
if (!xlog_is_shutdown(log) &&
iclog->ic_state != XLOG_STATE_ACTIVE &&
iclog->ic_state != XLOG_STATE_DIRTY) {
XFS_STATS_INC(log->l_mp, xs_log_force_sleep);
xlog_wait(&iclog->ic_force_wait, &log->l_icloglock);
} else {
spin_unlock(&log->l_icloglock);
}
if (xlog_is_shutdown(log))
return -EIO;
return 0;
}
/*
* Write out an unmount record using the ticket provided. We have to account for
* the data space used in the unmount ticket as this write is not done from a
* transaction context that has already done the accounting for us.
*/
static int
xlog_write_unmount_record(
struct xlog *log,
struct xlog_ticket *ticket)
{
struct {
struct xlog_op_header ophdr;
struct xfs_unmount_log_format ulf;
} unmount_rec = {
.ophdr = {
.oh_clientid = XFS_LOG,
.oh_tid = cpu_to_be32(ticket->t_tid),
.oh_flags = XLOG_UNMOUNT_TRANS,
},
.ulf = {
.magic = XLOG_UNMOUNT_TYPE,
},
};
struct xfs_log_iovec reg = {
.i_addr = &unmount_rec,
.i_len = sizeof(unmount_rec),
.i_type = XLOG_REG_TYPE_UNMOUNT,
};
struct xfs_log_vec vec = {
.lv_niovecs = 1,
.lv_iovecp = ®,
};
LIST_HEAD(lv_chain);
list_add(&vec.lv_list, &lv_chain);
BUILD_BUG_ON((sizeof(struct xlog_op_header) +
sizeof(struct xfs_unmount_log_format)) !=
sizeof(unmount_rec));
/* account for space used by record data */
ticket->t_curr_res -= sizeof(unmount_rec);
return xlog_write(log, NULL, &lv_chain, ticket, reg.i_len);
}
/*
* Mark the filesystem clean by writing an unmount record to the head of the
* log.
*/
static void
xlog_unmount_write(
struct xlog *log)
{
struct xfs_mount *mp = log->l_mp;
struct xlog_in_core *iclog;
struct xlog_ticket *tic = NULL;
int error;
error = xfs_log_reserve(mp, 600, 1, &tic, 0);
if (error)
goto out_err;
error = xlog_write_unmount_record(log, tic);
/*
* At this point, we're umounting anyway, so there's no point in
* transitioning log state to shutdown. Just continue...
*/
out_err:
if (error)
xfs_alert(mp, "%s: unmount record failed", __func__);
spin_lock(&log->l_icloglock);
iclog = log->l_iclog;
error = xlog_force_iclog(iclog);
xlog_wait_on_iclog(iclog);
if (tic) {
trace_xfs_log_umount_write(log, tic);
xfs_log_ticket_ungrant(log, tic);
}
}
static void
xfs_log_unmount_verify_iclog(
struct xlog *log)
{
struct xlog_in_core *iclog = log->l_iclog;
do {
ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
ASSERT(iclog->ic_offset == 0);
} while ((iclog = iclog->ic_next) != log->l_iclog);
}
/*
* Unmount record used to have a string "Unmount filesystem--" in the
* data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
* We just write the magic number now since that particular field isn't
* currently architecture converted and "Unmount" is a bit foo.
* As far as I know, there weren't any dependencies on the old behaviour.
*/
static void
xfs_log_unmount_write(
struct xfs_mount *mp)
{
struct xlog *log = mp->m_log;
if (!xfs_log_writable(mp))
return;
xfs_log_force(mp, XFS_LOG_SYNC);
if (xlog_is_shutdown(log))
return;
/*
* If we think the summary counters are bad, avoid writing the unmount
* record to force log recovery at next mount, after which the summary
* counters will be recalculated. Refer to xlog_check_unmount_rec for
* more details.
*/
if (XFS_TEST_ERROR(xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS), mp,
XFS_ERRTAG_FORCE_SUMMARY_RECALC)) {
xfs_alert(mp, "%s: will fix summary counters at next mount",
__func__);
return;
}
xfs_log_unmount_verify_iclog(log);
xlog_unmount_write(log);
}
/*
* Empty the log for unmount/freeze.
*
* To do this, we first need to shut down the background log work so it is not
* trying to cover the log as we clean up. We then need to unpin all objects in
* the log so we can then flush them out. Once they have completed their IO and
* run the callbacks removing themselves from the AIL, we can cover the log.
*/
int
xfs_log_quiesce(
struct xfs_mount *mp)
{
/*
* Clear log incompat features since we're quiescing the log. Report
* failures, though it's not fatal to have a higher log feature
* protection level than the log contents actually require.
*/
if (xfs_clear_incompat_log_features(mp)) {
int error;
error = xfs_sync_sb(mp, false);
if (error)
xfs_warn(mp,
"Failed to clear log incompat features on quiesce");
}
cancel_delayed_work_sync(&mp->m_log->l_work);
xfs_log_force(mp, XFS_LOG_SYNC);
/*
* The superblock buffer is uncached and while xfs_ail_push_all_sync()
* will push it, xfs_buftarg_wait() will not wait for it. Further,
* xfs_buf_iowait() cannot be used because it was pushed with the
* XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for
* the IO to complete.
*/
xfs_ail_push_all_sync(mp->m_ail);
xfs_buftarg_wait(mp->m_ddev_targp);
xfs_buf_lock(mp->m_sb_bp);
xfs_buf_unlock(mp->m_sb_bp);
return xfs_log_cover(mp);
}
void
xfs_log_clean(
struct xfs_mount *mp)
{
xfs_log_quiesce(mp);
xfs_log_unmount_write(mp);
}
/*
* Shut down and release the AIL and Log.
*
* During unmount, we need to ensure we flush all the dirty metadata objects
* from the AIL so that the log is empty before we write the unmount record to
* the log. Once this is done, we can tear down the AIL and the log.
*/
void
xfs_log_unmount(
struct xfs_mount *mp)
{
xfs_log_clean(mp);
/*
* If shutdown has come from iclog IO context, the log
* cleaning will have been skipped and so we need to wait
* for the iclog to complete shutdown processing before we
* tear anything down.
*/
xlog_wait_iclog_completion(mp->m_log);
xfs_buftarg_drain(mp->m_ddev_targp);
xfs_trans_ail_destroy(mp);
xfs_sysfs_del(&mp->m_log->l_kobj);
xlog_dealloc_log(mp->m_log);
}
void
xfs_log_item_init(
struct xfs_mount *mp,
struct xfs_log_item *item,
int type,
const struct xfs_item_ops *ops)
{
item->li_log = mp->m_log;
item->li_ailp = mp->m_ail;
item->li_type = type;
item->li_ops = ops;
item->li_lv = NULL;
INIT_LIST_HEAD(&item->li_ail);
INIT_LIST_HEAD(&item->li_cil);
INIT_LIST_HEAD(&item->li_bio_list);
INIT_LIST_HEAD(&item->li_trans);
}
/*
* Wake up processes waiting for log space after we have moved the log tail.
*/
void
xfs_log_space_wake(
struct xfs_mount *mp)
{
struct xlog *log = mp->m_log;
int free_bytes;
if (xlog_is_shutdown(log))
return;
if (!list_empty_careful(&log->l_write_head.waiters)) {
ASSERT(!xlog_in_recovery(log));
spin_lock(&log->l_write_head.lock);
free_bytes = xlog_space_left(log, &log->l_write_head.grant);
xlog_grant_head_wake(log, &log->l_write_head, &free_bytes);
spin_unlock(&log->l_write_head.lock);
}
if (!list_empty_careful(&log->l_reserve_head.waiters)) {
ASSERT(!xlog_in_recovery(log));
spin_lock(&log->l_reserve_head.lock);
free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes);
spin_unlock(&log->l_reserve_head.lock);
}
}
/*
* Determine if we have a transaction that has gone to disk that needs to be
* covered. To begin the transition to the idle state firstly the log needs to
* be idle. That means the CIL, the AIL and the iclogs needs to be empty before
* we start attempting to cover the log.
*
* Only if we are then in a state where covering is needed, the caller is
* informed that dummy transactions are required to move the log into the idle
* state.
*
* If there are any items in the AIl or CIL, then we do not want to attempt to
* cover the log as we may be in a situation where there isn't log space
* available to run a dummy transaction and this can lead to deadlocks when the
* tail of the log is pinned by an item that is modified in the CIL. Hence
* there's no point in running a dummy transaction at this point because we
* can't start trying to idle the log until both the CIL and AIL are empty.
*/
static bool
xfs_log_need_covered(
struct xfs_mount *mp)
{
struct xlog *log = mp->m_log;
bool needed = false;
if (!xlog_cil_empty(log))
return false;
spin_lock(&log->l_icloglock);
switch (log->l_covered_state) {
case XLOG_STATE_COVER_DONE:
case XLOG_STATE_COVER_DONE2:
case XLOG_STATE_COVER_IDLE:
break;
case XLOG_STATE_COVER_NEED:
case XLOG_STATE_COVER_NEED2:
if (xfs_ail_min_lsn(log->l_ailp))
break;
if (!xlog_iclogs_empty(log))
break;
needed = true;
if (log->l_covered_state == XLOG_STATE_COVER_NEED)
log->l_covered_state = XLOG_STATE_COVER_DONE;
else
log->l_covered_state = XLOG_STATE_COVER_DONE2;
break;
default:
needed = true;
break;
}
spin_unlock(&log->l_icloglock);
return needed;
}
/*
* Explicitly cover the log. This is similar to background log covering but
* intended for usage in quiesce codepaths. The caller is responsible to ensure
* the log is idle and suitable for covering. The CIL, iclog buffers and AIL
* must all be empty.
*/
static int
xfs_log_cover(
struct xfs_mount *mp)
{
int error = 0;
bool need_covered;
ASSERT((xlog_cil_empty(mp->m_log) && xlog_iclogs_empty(mp->m_log) &&
!xfs_ail_min_lsn(mp->m_log->l_ailp)) ||
xlog_is_shutdown(mp->m_log));
if (!xfs_log_writable(mp))
return 0;
/*
* xfs_log_need_covered() is not idempotent because it progresses the
* state machine if the log requires covering. Therefore, we must call
* this function once and use the result until we've issued an sb sync.
* Do so first to make that abundantly clear.
*
* Fall into the covering sequence if the log needs covering or the
* mount has lazy superblock accounting to sync to disk. The sb sync
* used for covering accumulates the in-core counters, so covering
* handles this for us.
*/
need_covered = xfs_log_need_covered(mp);
if (!need_covered && !xfs_has_lazysbcount(mp))
return 0;
/*
* To cover the log, commit the superblock twice (at most) in
* independent checkpoints. The first serves as a reference for the
* tail pointer. The sync transaction and AIL push empties the AIL and
* updates the in-core tail to the LSN of the first checkpoint. The
* second commit updates the on-disk tail with the in-core LSN,
* covering the log. Push the AIL one more time to leave it empty, as
* we found it.
*/
do {
error = xfs_sync_sb(mp, true);
if (error)
break;
xfs_ail_push_all_sync(mp->m_ail);
} while (xfs_log_need_covered(mp));
return error;
}
/*
* We may be holding the log iclog lock upon entering this routine.
*/
xfs_lsn_t
xlog_assign_tail_lsn_locked(
struct xfs_mount *mp)
{
struct xlog *log = mp->m_log;
struct xfs_log_item *lip;
xfs_lsn_t tail_lsn;
assert_spin_locked(&mp->m_ail->ail_lock);
/*
* To make sure we always have a valid LSN for the log tail we keep
* track of the last LSN which was committed in log->l_last_sync_lsn,
* and use that when the AIL was empty.
*/
lip = xfs_ail_min(mp->m_ail);
if (lip)
tail_lsn = lip->li_lsn;
else
tail_lsn = atomic64_read(&log->l_last_sync_lsn);
trace_xfs_log_assign_tail_lsn(log, tail_lsn);
atomic64_set(&log->l_tail_lsn, tail_lsn);
return tail_lsn;
}
xfs_lsn_t
xlog_assign_tail_lsn(
struct xfs_mount *mp)
{
xfs_lsn_t tail_lsn;
spin_lock(&mp->m_ail->ail_lock);
tail_lsn = xlog_assign_tail_lsn_locked(mp);
spin_unlock(&mp->m_ail->ail_lock);
return tail_lsn;
}
/*
* Return the space in the log between the tail and the head. The head
* is passed in the cycle/bytes formal parms. In the special case where
* the reserve head has wrapped passed the tail, this calculation is no
* longer valid. In this case, just return 0 which means there is no space
* in the log. This works for all places where this function is called
* with the reserve head. Of course, if the write head were to ever
* wrap the tail, we should blow up. Rather than catch this case here,
* we depend on other ASSERTions in other parts of the code. XXXmiken
*
* If reservation head is behind the tail, we have a problem. Warn about it,
* but then treat it as if the log is empty.
*
* If the log is shut down, the head and tail may be invalid or out of whack, so
* shortcut invalidity asserts in this case so that we don't trigger them
* falsely.
*/
STATIC int
xlog_space_left(
struct xlog *log,
atomic64_t *head)
{
int tail_bytes;
int tail_cycle;
int head_cycle;
int head_bytes;
xlog_crack_grant_head(head, &head_cycle, &head_bytes);
xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes);
tail_bytes = BBTOB(tail_bytes);
if (tail_cycle == head_cycle && head_bytes >= tail_bytes)
return log->l_logsize - (head_bytes - tail_bytes);
if (tail_cycle + 1 < head_cycle)
return 0;
/* Ignore potential inconsistency when shutdown. */
if (xlog_is_shutdown(log))
return log->l_logsize;
if (tail_cycle < head_cycle) {
ASSERT(tail_cycle == (head_cycle - 1));
return tail_bytes - head_bytes;
}
/*
* The reservation head is behind the tail. In this case we just want to
* return the size of the log as the amount of space left.
*/
xfs_alert(log->l_mp, "xlog_space_left: head behind tail");
xfs_alert(log->l_mp, " tail_cycle = %d, tail_bytes = %d",
tail_cycle, tail_bytes);
xfs_alert(log->l_mp, " GH cycle = %d, GH bytes = %d",
head_cycle, head_bytes);
ASSERT(0);
return log->l_logsize;
}
static void
xlog_ioend_work(
struct work_struct *work)
{
struct xlog_in_core *iclog =
container_of(work, struct xlog_in_core, ic_end_io_work);
struct xlog *log = iclog->ic_log;
int error;
error = blk_status_to_errno(iclog->ic_bio.bi_status);
#ifdef DEBUG
/* treat writes with injected CRC errors as failed */
if (iclog->ic_fail_crc)
error = -EIO;
#endif
/*
* Race to shutdown the filesystem if we see an error.
*/
if (XFS_TEST_ERROR(error, log->l_mp, XFS_ERRTAG_IODONE_IOERR)) {
xfs_alert(log->l_mp, "log I/O error %d", error);
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
}
xlog_state_done_syncing(iclog);
bio_uninit(&iclog->ic_bio);
/*
* Drop the lock to signal that we are done. Nothing references the
* iclog after this, so an unmount waiting on this lock can now tear it
* down safely. As such, it is unsafe to reference the iclog after the
* unlock as we could race with it being freed.
*/
up(&iclog->ic_sema);
}
/*
* Return size of each in-core log record buffer.
*
* All machines get 8 x 32kB buffers by default, unless tuned otherwise.
*
* If the filesystem blocksize is too large, we may need to choose a
* larger size since the directory code currently logs entire blocks.
*/
STATIC void
xlog_get_iclog_buffer_size(
struct xfs_mount *mp,
struct xlog *log)
{
if (mp->m_logbufs <= 0)
mp->m_logbufs = XLOG_MAX_ICLOGS;
if (mp->m_logbsize <= 0)
mp->m_logbsize = XLOG_BIG_RECORD_BSIZE;
log->l_iclog_bufs = mp->m_logbufs;
log->l_iclog_size = mp->m_logbsize;
/*
* # headers = size / 32k - one header holds cycles from 32k of data.
*/
log->l_iclog_heads =
DIV_ROUND_UP(mp->m_logbsize, XLOG_HEADER_CYCLE_SIZE);
log->l_iclog_hsize = log->l_iclog_heads << BBSHIFT;
}
void
xfs_log_work_queue(
struct xfs_mount *mp)
{
queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work,
msecs_to_jiffies(xfs_syncd_centisecs * 10));
}
/*
* Clear the log incompat flags if we have the opportunity.
*
* This only happens if we're about to log the second dummy transaction as part
* of covering the log and we can get the log incompat feature usage lock.
*/
static inline void
xlog_clear_incompat(
struct xlog *log)
{
struct xfs_mount *mp = log->l_mp;
if (!xfs_sb_has_incompat_log_feature(&mp->m_sb,
XFS_SB_FEAT_INCOMPAT_LOG_ALL))
return;
if (log->l_covered_state != XLOG_STATE_COVER_DONE2)
return;
if (!down_write_trylock(&log->l_incompat_users))
return;
xfs_clear_incompat_log_features(mp);
up_write(&log->l_incompat_users);
}
/*
* Every sync period we need to unpin all items in the AIL and push them to
* disk. If there is nothing dirty, then we might need to cover the log to
* indicate that the filesystem is idle.
*/
static void
xfs_log_worker(
struct work_struct *work)
{
struct xlog *log = container_of(to_delayed_work(work),
struct xlog, l_work);
struct xfs_mount *mp = log->l_mp;
/* dgc: errors ignored - not fatal and nowhere to report them */
if (xfs_fs_writable(mp, SB_FREEZE_WRITE) && xfs_log_need_covered(mp)) {
/*
* Dump a transaction into the log that contains no real change.
* This is needed to stamp the current tail LSN into the log
* during the covering operation.
*
* We cannot use an inode here for this - that will push dirty
* state back up into the VFS and then periodic inode flushing
* will prevent log covering from making progress. Hence we
* synchronously log the superblock instead to ensure the
* superblock is immediately unpinned and can be written back.
*/
xlog_clear_incompat(log);
xfs_sync_sb(mp, true);
} else
xfs_log_force(mp, 0);
/* start pushing all the metadata that is currently dirty */
xfs_ail_push_all(mp->m_ail);
/* queue us up again */
xfs_log_work_queue(mp);
}
/*
* This routine initializes some of the log structure for a given mount point.
* Its primary purpose is to fill in enough, so recovery can occur. However,
* some other stuff may be filled in too.
*/
STATIC struct xlog *
xlog_alloc_log(
struct xfs_mount *mp,
struct xfs_buftarg *log_target,
xfs_daddr_t blk_offset,
int num_bblks)
{
struct xlog *log;
xlog_rec_header_t *head;
xlog_in_core_t **iclogp;
xlog_in_core_t *iclog, *prev_iclog=NULL;
int i;
int error = -ENOMEM;
uint log2_size = 0;
log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL);
if (!log) {
xfs_warn(mp, "Log allocation failed: No memory!");
goto out;
}
log->l_mp = mp;
log->l_targ = log_target;
log->l_logsize = BBTOB(num_bblks);
log->l_logBBstart = blk_offset;
log->l_logBBsize = num_bblks;
log->l_covered_state = XLOG_STATE_COVER_IDLE;
set_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
INIT_DELAYED_WORK(&log->l_work, xfs_log_worker);
log->l_prev_block = -1;
/* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0);
xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
log->l_curr_cycle = 1; /* 0 is bad since this is initial value */
if (xfs_has_logv2(mp) && mp->m_sb.sb_logsunit > 1)
log->l_iclog_roundoff = mp->m_sb.sb_logsunit;
else
log->l_iclog_roundoff = BBSIZE;
xlog_grant_head_init(&log->l_reserve_head);
xlog_grant_head_init(&log->l_write_head);
error = -EFSCORRUPTED;
if (xfs_has_sector(mp)) {
log2_size = mp->m_sb.sb_logsectlog;
if (log2_size < BBSHIFT) {
xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)",
log2_size, BBSHIFT);
goto out_free_log;
}
log2_size -= BBSHIFT;
if (log2_size > mp->m_sectbb_log) {
xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)",
log2_size, mp->m_sectbb_log);
goto out_free_log;
}
/* for larger sector sizes, must have v2 or external log */
if (log2_size && log->l_logBBstart > 0 &&
!xfs_has_logv2(mp)) {
xfs_warn(mp,
"log sector size (0x%x) invalid for configuration.",
log2_size);
goto out_free_log;
}
}
log->l_sectBBsize = 1 << log2_size;
init_rwsem(&log->l_incompat_users);
xlog_get_iclog_buffer_size(mp, log);
spin_lock_init(&log->l_icloglock);
init_waitqueue_head(&log->l_flush_wait);
iclogp = &log->l_iclog;
/*
* The amount of memory to allocate for the iclog structure is
* rather funky due to the way the structure is defined. It is
* done this way so that we can use different sizes for machines
* with different amounts of memory. See the definition of
* xlog_in_core_t in xfs_log_priv.h for details.
*/
ASSERT(log->l_iclog_size >= 4096);
for (i = 0; i < log->l_iclog_bufs; i++) {
size_t bvec_size = howmany(log->l_iclog_size, PAGE_SIZE) *
sizeof(struct bio_vec);
iclog = kmem_zalloc(sizeof(*iclog) + bvec_size, KM_MAYFAIL);
if (!iclog)
goto out_free_iclog;
*iclogp = iclog;
iclog->ic_prev = prev_iclog;
prev_iclog = iclog;
iclog->ic_data = kvzalloc(log->l_iclog_size,
GFP_KERNEL | __GFP_RETRY_MAYFAIL);
if (!iclog->ic_data)
goto out_free_iclog;
head = &iclog->ic_header;
memset(head, 0, sizeof(xlog_rec_header_t));
head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
head->h_version = cpu_to_be32(
xfs_has_logv2(log->l_mp) ? 2 : 1);
head->h_size = cpu_to_be32(log->l_iclog_size);
/* new fields */
head->h_fmt = cpu_to_be32(XLOG_FMT);
memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
iclog->ic_size = log->l_iclog_size - log->l_iclog_hsize;
iclog->ic_state = XLOG_STATE_ACTIVE;
iclog->ic_log = log;
atomic_set(&iclog->ic_refcnt, 0);
INIT_LIST_HEAD(&iclog->ic_callbacks);
iclog->ic_datap = (void *)iclog->ic_data + log->l_iclog_hsize;
init_waitqueue_head(&iclog->ic_force_wait);
init_waitqueue_head(&iclog->ic_write_wait);
INIT_WORK(&iclog->ic_end_io_work, xlog_ioend_work);
sema_init(&iclog->ic_sema, 1);
iclogp = &iclog->ic_next;
}
*iclogp = log->l_iclog; /* complete ring */
log->l_iclog->ic_prev = prev_iclog; /* re-write 1st prev ptr */
log->l_ioend_workqueue = alloc_workqueue("xfs-log/%s",
XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM |
WQ_HIGHPRI),
0, mp->m_super->s_id);
if (!log->l_ioend_workqueue)
goto out_free_iclog;
error = xlog_cil_init(log);
if (error)
goto out_destroy_workqueue;
return log;
out_destroy_workqueue:
destroy_workqueue(log->l_ioend_workqueue);
out_free_iclog:
for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
prev_iclog = iclog->ic_next;
kmem_free(iclog->ic_data);
kmem_free(iclog);
if (prev_iclog == log->l_iclog)
break;
}
out_free_log:
kmem_free(log);
out:
return ERR_PTR(error);
} /* xlog_alloc_log */
/*
* Compute the LSN that we'd need to push the log tail towards in order to have
* (a) enough on-disk log space to log the number of bytes specified, (b) at
* least 25% of the log space free, and (c) at least 256 blocks free. If the
* log free space already meets all three thresholds, this function returns
* NULLCOMMITLSN.
*/
xfs_lsn_t
xlog_grant_push_threshold(
struct xlog *log,
int need_bytes)
{
xfs_lsn_t threshold_lsn = 0;
xfs_lsn_t last_sync_lsn;
int free_blocks;
int free_bytes;
int threshold_block;
int threshold_cycle;
int free_threshold;
ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
free_bytes = xlog_space_left(log, &log->l_reserve_head.grant);
free_blocks = BTOBBT(free_bytes);
/*
* Set the threshold for the minimum number of free blocks in the
* log to the maximum of what the caller needs, one quarter of the
* log, and 256 blocks.
*/
free_threshold = BTOBB(need_bytes);
free_threshold = max(free_threshold, (log->l_logBBsize >> 2));
free_threshold = max(free_threshold, 256);
if (free_blocks >= free_threshold)
return NULLCOMMITLSN;
xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle,
&threshold_block);
threshold_block += free_threshold;
if (threshold_block >= log->l_logBBsize) {
threshold_block -= log->l_logBBsize;
threshold_cycle += 1;
}
threshold_lsn = xlog_assign_lsn(threshold_cycle,
threshold_block);
/*
* Don't pass in an lsn greater than the lsn of the last
* log record known to be on disk. Use a snapshot of the last sync lsn
* so that it doesn't change between the compare and the set.
*/
last_sync_lsn = atomic64_read(&log->l_last_sync_lsn);
if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0)
threshold_lsn = last_sync_lsn;
return threshold_lsn;
}
/*
* Push the tail of the log if we need to do so to maintain the free log space
* thresholds set out by xlog_grant_push_threshold. We may need to adopt a
* policy which pushes on an lsn which is further along in the log once we
* reach the high water mark. In this manner, we would be creating a low water
* mark.
*/
STATIC void
xlog_grant_push_ail(
struct xlog *log,
int need_bytes)
{
xfs_lsn_t threshold_lsn;
threshold_lsn = xlog_grant_push_threshold(log, need_bytes);
if (threshold_lsn == NULLCOMMITLSN || xlog_is_shutdown(log))
return;
/*
* Get the transaction layer to kick the dirty buffers out to
* disk asynchronously. No point in trying to do this if
* the filesystem is shutting down.
*/
xfs_ail_push(log->l_ailp, threshold_lsn);
}
/*
* Stamp cycle number in every block
*/
STATIC void
xlog_pack_data(
struct xlog *log,
struct xlog_in_core *iclog,
int roundoff)
{
int i, j, k;
int size = iclog->ic_offset + roundoff;
__be32 cycle_lsn;
char *dp;
cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn);
dp = iclog->ic_datap;
for (i = 0; i < BTOBB(size); i++) {
if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE))
break;
iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp;
*(__be32 *)dp = cycle_lsn;
dp += BBSIZE;
}
if (xfs_has_logv2(log->l_mp)) {
xlog_in_core_2_t *xhdr = iclog->ic_data;
for ( ; i < BTOBB(size); i++) {
j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp;
*(__be32 *)dp = cycle_lsn;
dp += BBSIZE;
}
for (i = 1; i < log->l_iclog_heads; i++)
xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
}
}
/*
* Calculate the checksum for a log buffer.
*
* This is a little more complicated than it should be because the various
* headers and the actual data are non-contiguous.
*/
__le32
xlog_cksum(
struct xlog *log,
struct xlog_rec_header *rhead,
char *dp,
int size)
{
uint32_t crc;
/* first generate the crc for the record header ... */
crc = xfs_start_cksum_update((char *)rhead,
sizeof(struct xlog_rec_header),
offsetof(struct xlog_rec_header, h_crc));
/* ... then for additional cycle data for v2 logs ... */
if (xfs_has_logv2(log->l_mp)) {
union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead;
int i;
int xheads;
xheads = DIV_ROUND_UP(size, XLOG_HEADER_CYCLE_SIZE);
for (i = 1; i < xheads; i++) {
crc = crc32c(crc, &xhdr[i].hic_xheader,
sizeof(struct xlog_rec_ext_header));
}
}
/* ... and finally for the payload */
crc = crc32c(crc, dp, size);
return xfs_end_cksum(crc);
}
static void
xlog_bio_end_io(
struct bio *bio)
{
struct xlog_in_core *iclog = bio->bi_private;
queue_work(iclog->ic_log->l_ioend_workqueue,
&iclog->ic_end_io_work);
}
static int
xlog_map_iclog_data(
struct bio *bio,
void *data,
size_t count)
{
do {
struct page *page = kmem_to_page(data);
unsigned int off = offset_in_page(data);
size_t len = min_t(size_t, count, PAGE_SIZE - off);
if (bio_add_page(bio, page, len, off) != len)
return -EIO;
data += len;
count -= len;
} while (count);
return 0;
}
STATIC void
xlog_write_iclog(
struct xlog *log,
struct xlog_in_core *iclog,
uint64_t bno,
unsigned int count)
{
ASSERT(bno < log->l_logBBsize);
trace_xlog_iclog_write(iclog, _RET_IP_);
/*
* We lock the iclogbufs here so that we can serialise against I/O
* completion during unmount. We might be processing a shutdown
* triggered during unmount, and that can occur asynchronously to the
* unmount thread, and hence we need to ensure that completes before
* tearing down the iclogbufs. Hence we need to hold the buffer lock
* across the log IO to archieve that.
*/
down(&iclog->ic_sema);
if (xlog_is_shutdown(log)) {
/*
* It would seem logical to return EIO here, but we rely on
* the log state machine to propagate I/O errors instead of
* doing it here. We kick of the state machine and unlock
* the buffer manually, the code needs to be kept in sync
* with the I/O completion path.
*/
xlog_state_done_syncing(iclog);
up(&iclog->ic_sema);
return;
}
/*
* We use REQ_SYNC | REQ_IDLE here to tell the block layer the are more
* IOs coming immediately after this one. This prevents the block layer
* writeback throttle from throttling log writes behind background
* metadata writeback and causing priority inversions.
*/
bio_init(&iclog->ic_bio, log->l_targ->bt_bdev, iclog->ic_bvec,
howmany(count, PAGE_SIZE),
REQ_OP_WRITE | REQ_META | REQ_SYNC | REQ_IDLE);
iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart + bno;
iclog->ic_bio.bi_end_io = xlog_bio_end_io;
iclog->ic_bio.bi_private = iclog;
if (iclog->ic_flags & XLOG_ICL_NEED_FLUSH) {
iclog->ic_bio.bi_opf |= REQ_PREFLUSH;
/*
* For external log devices, we also need to flush the data
* device cache first to ensure all metadata writeback covered
* by the LSN in this iclog is on stable storage. This is slow,
* but it *must* complete before we issue the external log IO.
*
* If the flush fails, we cannot conclude that past metadata
* writeback from the log succeeded. Repeating the flush is
* not possible, hence we must shut down with log IO error to
* avoid shutdown re-entering this path and erroring out again.
*/
if (log->l_targ != log->l_mp->m_ddev_targp &&
blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev)) {
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
return;
}
}
if (iclog->ic_flags & XLOG_ICL_NEED_FUA)
iclog->ic_bio.bi_opf |= REQ_FUA;
iclog->ic_flags &= ~(XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA);
if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count)) {
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
return;
}
if (is_vmalloc_addr(iclog->ic_data))
flush_kernel_vmap_range(iclog->ic_data, count);
/*
* If this log buffer would straddle the end of the log we will have
* to split it up into two bios, so that we can continue at the start.
*/
if (bno + BTOBB(count) > log->l_logBBsize) {
struct bio *split;
split = bio_split(&iclog->ic_bio, log->l_logBBsize - bno,
GFP_NOIO, &fs_bio_set);
bio_chain(split, &iclog->ic_bio);
submit_bio(split);
/* restart at logical offset zero for the remainder */
iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart;
}
submit_bio(&iclog->ic_bio);
}
/*
* We need to bump cycle number for the part of the iclog that is
* written to the start of the log. Watch out for the header magic
* number case, though.
*/
static void
xlog_split_iclog(
struct xlog *log,
void *data,
uint64_t bno,
unsigned int count)
{
unsigned int split_offset = BBTOB(log->l_logBBsize - bno);
unsigned int i;
for (i = split_offset; i < count; i += BBSIZE) {
uint32_t cycle = get_unaligned_be32(data + i);
if (++cycle == XLOG_HEADER_MAGIC_NUM)
cycle++;
put_unaligned_be32(cycle, data + i);
}
}
static int
xlog_calc_iclog_size(
struct xlog *log,
struct xlog_in_core *iclog,
uint32_t *roundoff)
{
uint32_t count_init, count;
/* Add for LR header */
count_init = log->l_iclog_hsize + iclog->ic_offset;
count = roundup(count_init, log->l_iclog_roundoff);
*roundoff = count - count_init;
ASSERT(count >= count_init);
ASSERT(*roundoff < log->l_iclog_roundoff);
return count;
}
/*
* Flush out the in-core log (iclog) to the on-disk log in an asynchronous
* fashion. Previously, we should have moved the current iclog
* ptr in the log to point to the next available iclog. This allows further
* write to continue while this code syncs out an iclog ready to go.
* Before an in-core log can be written out, the data section must be scanned
* to save away the 1st word of each BBSIZE block into the header. We replace
* it with the current cycle count. Each BBSIZE block is tagged with the
* cycle count because there in an implicit assumption that drives will
* guarantee that entire 512 byte blocks get written at once. In other words,
* we can't have part of a 512 byte block written and part not written. By
* tagging each block, we will know which blocks are valid when recovering
* after an unclean shutdown.
*
* This routine is single threaded on the iclog. No other thread can be in
* this routine with the same iclog. Changing contents of iclog can there-
* fore be done without grabbing the state machine lock. Updating the global
* log will require grabbing the lock though.
*
* The entire log manager uses a logical block numbering scheme. Only
* xlog_write_iclog knows about the fact that the log may not start with
* block zero on a given device.
*/
STATIC void
xlog_sync(
struct xlog *log,
struct xlog_in_core *iclog,
struct xlog_ticket *ticket)
{
unsigned int count; /* byte count of bwrite */
unsigned int roundoff; /* roundoff to BB or stripe */
uint64_t bno;
unsigned int size;
ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
trace_xlog_iclog_sync(iclog, _RET_IP_);
count = xlog_calc_iclog_size(log, iclog, &roundoff);
/*
* If we have a ticket, account for the roundoff via the ticket
* reservation to avoid touching the hot grant heads needlessly.
* Otherwise, we have to move grant heads directly.
*/
if (ticket) {
ticket->t_curr_res -= roundoff;
} else {
xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff);
xlog_grant_add_space(log, &log->l_write_head.grant, roundoff);
}
/* put cycle number in every block */
xlog_pack_data(log, iclog, roundoff);
/* real byte length */
size = iclog->ic_offset;
if (xfs_has_logv2(log->l_mp))
size += roundoff;
iclog->ic_header.h_len = cpu_to_be32(size);
XFS_STATS_INC(log->l_mp, xs_log_writes);
XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count));
bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn));
/* Do we need to split this write into 2 parts? */
if (bno + BTOBB(count) > log->l_logBBsize)
xlog_split_iclog(log, &iclog->ic_header, bno, count);
/* calculcate the checksum */
iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header,
iclog->ic_datap, size);
/*
* Intentionally corrupt the log record CRC based on the error injection
* frequency, if defined. This facilitates testing log recovery in the
* event of torn writes. Hence, set the IOABORT state to abort the log
* write on I/O completion and shutdown the fs. The subsequent mount
* detects the bad CRC and attempts to recover.
*/
#ifdef DEBUG
if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) {
iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA);
iclog->ic_fail_crc = true;
xfs_warn(log->l_mp,
"Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.",
be64_to_cpu(iclog->ic_header.h_lsn));
}
#endif
xlog_verify_iclog(log, iclog, count);
xlog_write_iclog(log, iclog, bno, count);
}
/*
* Deallocate a log structure
*/
STATIC void
xlog_dealloc_log(
struct xlog *log)
{
xlog_in_core_t *iclog, *next_iclog;
int i;
/*
* Destroy the CIL after waiting for iclog IO completion because an
* iclog EIO error will try to shut down the log, which accesses the
* CIL to wake up the waiters.
*/
xlog_cil_destroy(log);
iclog = log->l_iclog;
for (i = 0; i < log->l_iclog_bufs; i++) {
next_iclog = iclog->ic_next;
kmem_free(iclog->ic_data);
kmem_free(iclog);
iclog = next_iclog;
}
log->l_mp->m_log = NULL;
destroy_workqueue(log->l_ioend_workqueue);
kmem_free(log);
}
/*
* Update counters atomically now that memcpy is done.
*/
static inline void
xlog_state_finish_copy(
struct xlog *log,
struct xlog_in_core *iclog,
int record_cnt,
int copy_bytes)
{
lockdep_assert_held(&log->l_icloglock);
be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
iclog->ic_offset += copy_bytes;
}
/*
* print out info relating to regions written which consume
* the reservation
*/
void
xlog_print_tic_res(
struct xfs_mount *mp,
struct xlog_ticket *ticket)
{
xfs_warn(mp, "ticket reservation summary:");
xfs_warn(mp, " unit res = %d bytes", ticket->t_unit_res);
xfs_warn(mp, " current res = %d bytes", ticket->t_curr_res);
xfs_warn(mp, " original count = %d", ticket->t_ocnt);
xfs_warn(mp, " remaining count = %d", ticket->t_cnt);
}
/*
* Print a summary of the transaction.
*/
void
xlog_print_trans(
struct xfs_trans *tp)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_log_item *lip;
/* dump core transaction and ticket info */
xfs_warn(mp, "transaction summary:");
xfs_warn(mp, " log res = %d", tp->t_log_res);
xfs_warn(mp, " log count = %d", tp->t_log_count);
xfs_warn(mp, " flags = 0x%x", tp->t_flags);
xlog_print_tic_res(mp, tp->t_ticket);
/* dump each log item */
list_for_each_entry(lip, &tp->t_items, li_trans) {
struct xfs_log_vec *lv = lip->li_lv;
struct xfs_log_iovec *vec;
int i;
xfs_warn(mp, "log item: ");
xfs_warn(mp, " type = 0x%x", lip->li_type);
xfs_warn(mp, " flags = 0x%lx", lip->li_flags);
if (!lv)
continue;
xfs_warn(mp, " niovecs = %d", lv->lv_niovecs);
xfs_warn(mp, " size = %d", lv->lv_size);
xfs_warn(mp, " bytes = %d", lv->lv_bytes);
xfs_warn(mp, " buf len = %d", lv->lv_buf_len);
/* dump each iovec for the log item */
vec = lv->lv_iovecp;
for (i = 0; i < lv->lv_niovecs; i++) {
int dumplen = min(vec->i_len, 32);
xfs_warn(mp, " iovec[%d]", i);
xfs_warn(mp, " type = 0x%x", vec->i_type);
xfs_warn(mp, " len = %d", vec->i_len);
xfs_warn(mp, " first %d bytes of iovec[%d]:", dumplen, i);
xfs_hex_dump(vec->i_addr, dumplen);
vec++;
}
}
}
static inline void
xlog_write_iovec(
struct xlog_in_core *iclog,
uint32_t *log_offset,
void *data,
uint32_t write_len,
int *bytes_left,
uint32_t *record_cnt,
uint32_t *data_cnt)
{
ASSERT(*log_offset < iclog->ic_log->l_iclog_size);
ASSERT(*log_offset % sizeof(int32_t) == 0);
ASSERT(write_len % sizeof(int32_t) == 0);
memcpy(iclog->ic_datap + *log_offset, data, write_len);
*log_offset += write_len;
*bytes_left -= write_len;
(*record_cnt)++;
*data_cnt += write_len;
}
/*
* Write log vectors into a single iclog which is guaranteed by the caller
* to have enough space to write the entire log vector into.
*/
static void
xlog_write_full(
struct xfs_log_vec *lv,
struct xlog_ticket *ticket,
struct xlog_in_core *iclog,
uint32_t *log_offset,
uint32_t *len,
uint32_t *record_cnt,
uint32_t *data_cnt)
{
int index;
ASSERT(*log_offset + *len <= iclog->ic_size ||
iclog->ic_state == XLOG_STATE_WANT_SYNC);
/*
* Ordered log vectors have no regions to write so this
* loop will naturally skip them.
*/
for (index = 0; index < lv->lv_niovecs; index++) {
struct xfs_log_iovec *reg = &lv->lv_iovecp[index];
struct xlog_op_header *ophdr = reg->i_addr;
ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
xlog_write_iovec(iclog, log_offset, reg->i_addr,
reg->i_len, len, record_cnt, data_cnt);
}
}
static int
xlog_write_get_more_iclog_space(
struct xlog_ticket *ticket,
struct xlog_in_core **iclogp,
uint32_t *log_offset,
uint32_t len,
uint32_t *record_cnt,
uint32_t *data_cnt)
{
struct xlog_in_core *iclog = *iclogp;
struct xlog *log = iclog->ic_log;
int error;
spin_lock(&log->l_icloglock);
ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC);
xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
error = xlog_state_release_iclog(log, iclog, ticket);
spin_unlock(&log->l_icloglock);
if (error)
return error;
error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
log_offset);
if (error)
return error;
*record_cnt = 0;
*data_cnt = 0;
*iclogp = iclog;
return 0;
}
/*
* Write log vectors into a single iclog which is smaller than the current chain
* length. We write until we cannot fit a full record into the remaining space
* and then stop. We return the log vector that is to be written that cannot
* wholly fit in the iclog.
*/
static int
xlog_write_partial(
struct xfs_log_vec *lv,
struct xlog_ticket *ticket,
struct xlog_in_core **iclogp,
uint32_t *log_offset,
uint32_t *len,
uint32_t *record_cnt,
uint32_t *data_cnt)
{
struct xlog_in_core *iclog = *iclogp;
struct xlog_op_header *ophdr;
int index = 0;
uint32_t rlen;
int error;
/* walk the logvec, copying until we run out of space in the iclog */
for (index = 0; index < lv->lv_niovecs; index++) {
struct xfs_log_iovec *reg = &lv->lv_iovecp[index];
uint32_t reg_offset = 0;
/*
* The first region of a continuation must have a non-zero
* length otherwise log recovery will just skip over it and
* start recovering from the next opheader it finds. Because we
* mark the next opheader as a continuation, recovery will then
* incorrectly add the continuation to the previous region and
* that breaks stuff.
*
* Hence if there isn't space for region data after the
* opheader, then we need to start afresh with a new iclog.
*/
if (iclog->ic_size - *log_offset <=
sizeof(struct xlog_op_header)) {
error = xlog_write_get_more_iclog_space(ticket,
&iclog, log_offset, *len, record_cnt,
data_cnt);
if (error)
return error;
}
ophdr = reg->i_addr;
rlen = min_t(uint32_t, reg->i_len, iclog->ic_size - *log_offset);
ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
ophdr->oh_len = cpu_to_be32(rlen - sizeof(struct xlog_op_header));
if (rlen != reg->i_len)
ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
xlog_write_iovec(iclog, log_offset, reg->i_addr,
rlen, len, record_cnt, data_cnt);
/* If we wrote the whole region, move to the next. */
if (rlen == reg->i_len)
continue;
/*
* We now have a partially written iovec, but it can span
* multiple iclogs so we loop here. First we release the iclog
* we currently have, then we get a new iclog and add a new
* opheader. Then we continue copying from where we were until
* we either complete the iovec or fill the iclog. If we
* complete the iovec, then we increment the index and go right
* back to the top of the outer loop. if we fill the iclog, we
* run the inner loop again.
*
* This is complicated by the tail of a region using all the
* space in an iclog and hence requiring us to release the iclog
* and get a new one before returning to the outer loop. We must
* always guarantee that we exit this inner loop with at least
* space for log transaction opheaders left in the current
* iclog, hence we cannot just terminate the loop at the end
* of the of the continuation. So we loop while there is no
* space left in the current iclog, and check for the end of the
* continuation after getting a new iclog.
*/
do {
/*
* Ensure we include the continuation opheader in the
* space we need in the new iclog by adding that size
* to the length we require. This continuation opheader
* needs to be accounted to the ticket as the space it
* consumes hasn't been accounted to the lv we are
* writing.
*/
error = xlog_write_get_more_iclog_space(ticket,
&iclog, log_offset,
*len + sizeof(struct xlog_op_header),
record_cnt, data_cnt);
if (error)
return error;
ophdr = iclog->ic_datap + *log_offset;
ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
ophdr->oh_clientid = XFS_TRANSACTION;
ophdr->oh_res2 = 0;
ophdr->oh_flags = XLOG_WAS_CONT_TRANS;
ticket->t_curr_res -= sizeof(struct xlog_op_header);
*log_offset += sizeof(struct xlog_op_header);
*data_cnt += sizeof(struct xlog_op_header);
/*
* If rlen fits in the iclog, then end the region
* continuation. Otherwise we're going around again.
*/
reg_offset += rlen;
rlen = reg->i_len - reg_offset;
if (rlen <= iclog->ic_size - *log_offset)
ophdr->oh_flags |= XLOG_END_TRANS;
else
ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
rlen = min_t(uint32_t, rlen, iclog->ic_size - *log_offset);
ophdr->oh_len = cpu_to_be32(rlen);
xlog_write_iovec(iclog, log_offset,
reg->i_addr + reg_offset,
rlen, len, record_cnt, data_cnt);
} while (ophdr->oh_flags & XLOG_CONTINUE_TRANS);
}
/*
* No more iovecs remain in this logvec so return the next log vec to
* the caller so it can go back to fast path copying.
*/
*iclogp = iclog;
return 0;
}
/*
* Write some region out to in-core log
*
* This will be called when writing externally provided regions or when
* writing out a commit record for a given transaction.
*
* General algorithm:
* 1. Find total length of this write. This may include adding to the
* lengths passed in.
* 2. Check whether we violate the tickets reservation.
* 3. While writing to this iclog
* A. Reserve as much space in this iclog as can get
* B. If this is first write, save away start lsn
* C. While writing this region:
* 1. If first write of transaction, write start record
* 2. Write log operation header (header per region)
* 3. Find out if we can fit entire region into this iclog
* 4. Potentially, verify destination memcpy ptr
* 5. Memcpy (partial) region
* 6. If partial copy, release iclog; otherwise, continue
* copying more regions into current iclog
* 4. Mark want sync bit (in simulation mode)
* 5. Release iclog for potential flush to on-disk log.
*
* ERRORS:
* 1. Panic if reservation is overrun. This should never happen since
* reservation amounts are generated internal to the filesystem.
* NOTES:
* 1. Tickets are single threaded data structures.
* 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
* syncing routine. When a single log_write region needs to span
* multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
* on all log operation writes which don't contain the end of the
* region. The XLOG_END_TRANS bit is used for the in-core log
* operation which contains the end of the continued log_write region.
* 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
* we don't really know exactly how much space will be used. As a result,
* we don't update ic_offset until the end when we know exactly how many
* bytes have been written out.
*/
int
xlog_write(
struct xlog *log,
struct xfs_cil_ctx *ctx,
struct list_head *lv_chain,
struct xlog_ticket *ticket,
uint32_t len)
{
struct xlog_in_core *iclog = NULL;
struct xfs_log_vec *lv;
uint32_t record_cnt = 0;
uint32_t data_cnt = 0;
int error = 0;
int log_offset;
if (ticket->t_curr_res < 0) {
xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
"ctx ticket reservation ran out. Need to up reservation");
xlog_print_tic_res(log->l_mp, ticket);
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
}
error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
&log_offset);
if (error)
return error;
ASSERT(log_offset <= iclog->ic_size - 1);
/*
* If we have a context pointer, pass it the first iclog we are
* writing to so it can record state needed for iclog write
* ordering.
*/
if (ctx)
xlog_cil_set_ctx_write_state(ctx, iclog);
list_for_each_entry(lv, lv_chain, lv_list) {
/*
* If the entire log vec does not fit in the iclog, punt it to
* the partial copy loop which can handle this case.
*/
if (lv->lv_niovecs &&
lv->lv_bytes > iclog->ic_size - log_offset) {
error = xlog_write_partial(lv, ticket, &iclog,
&log_offset, &len, &record_cnt,
&data_cnt);
if (error) {
/*
* We have no iclog to release, so just return
* the error immediately.
*/
return error;
}
} else {
xlog_write_full(lv, ticket, iclog, &log_offset,
&len, &record_cnt, &data_cnt);
}
}
ASSERT(len == 0);
/*
* We've already been guaranteed that the last writes will fit inside
* the current iclog, and hence it will already have the space used by
* those writes accounted to it. Hence we do not need to update the
* iclog with the number of bytes written here.
*/
spin_lock(&log->l_icloglock);
xlog_state_finish_copy(log, iclog, record_cnt, 0);
error = xlog_state_release_iclog(log, iclog, ticket);
spin_unlock(&log->l_icloglock);
return error;
}
static void
xlog_state_activate_iclog(
struct xlog_in_core *iclog,
int *iclogs_changed)
{
ASSERT(list_empty_careful(&iclog->ic_callbacks));
trace_xlog_iclog_activate(iclog, _RET_IP_);
/*
* If the number of ops in this iclog indicate it just contains the
* dummy transaction, we can change state into IDLE (the second time
* around). Otherwise we should change the state into NEED a dummy.
* We don't need to cover the dummy.
*/
if (*iclogs_changed == 0 &&
iclog->ic_header.h_num_logops == cpu_to_be32(XLOG_COVER_OPS)) {
*iclogs_changed = 1;
} else {
/*
* We have two dirty iclogs so start over. This could also be
* num of ops indicating this is not the dummy going out.
*/
*iclogs_changed = 2;
}
iclog->ic_state = XLOG_STATE_ACTIVE;
iclog->ic_offset = 0;
iclog->ic_header.h_num_logops = 0;
memset(iclog->ic_header.h_cycle_data, 0,
sizeof(iclog->ic_header.h_cycle_data));
iclog->ic_header.h_lsn = 0;
iclog->ic_header.h_tail_lsn = 0;
}
/*
* Loop through all iclogs and mark all iclogs currently marked DIRTY as
* ACTIVE after iclog I/O has completed.
*/
static void
xlog_state_activate_iclogs(
struct xlog *log,
int *iclogs_changed)
{
struct xlog_in_core *iclog = log->l_iclog;
do {
if (iclog->ic_state == XLOG_STATE_DIRTY)
xlog_state_activate_iclog(iclog, iclogs_changed);
/*
* The ordering of marking iclogs ACTIVE must be maintained, so
* an iclog doesn't become ACTIVE beyond one that is SYNCING.
*/
else if (iclog->ic_state != XLOG_STATE_ACTIVE)
break;
} while ((iclog = iclog->ic_next) != log->l_iclog);
}
static int
xlog_covered_state(
int prev_state,
int iclogs_changed)
{
/*
* We go to NEED for any non-covering writes. We go to NEED2 if we just
* wrote the first covering record (DONE). We go to IDLE if we just
* wrote the second covering record (DONE2) and remain in IDLE until a
* non-covering write occurs.
*/
switch (prev_state) {
case XLOG_STATE_COVER_IDLE:
if (iclogs_changed == 1)
return XLOG_STATE_COVER_IDLE;
fallthrough;
case XLOG_STATE_COVER_NEED:
case XLOG_STATE_COVER_NEED2:
break;
case XLOG_STATE_COVER_DONE:
if (iclogs_changed == 1)
return XLOG_STATE_COVER_NEED2;
break;
case XLOG_STATE_COVER_DONE2:
if (iclogs_changed == 1)
return XLOG_STATE_COVER_IDLE;
break;
default:
ASSERT(0);
}
return XLOG_STATE_COVER_NEED;
}
STATIC void
xlog_state_clean_iclog(
struct xlog *log,
struct xlog_in_core *dirty_iclog)
{
int iclogs_changed = 0;
trace_xlog_iclog_clean(dirty_iclog, _RET_IP_);
dirty_iclog->ic_state = XLOG_STATE_DIRTY;
xlog_state_activate_iclogs(log, &iclogs_changed);
wake_up_all(&dirty_iclog->ic_force_wait);
if (iclogs_changed) {
log->l_covered_state = xlog_covered_state(log->l_covered_state,
iclogs_changed);
}
}
STATIC xfs_lsn_t
xlog_get_lowest_lsn(
struct xlog *log)
{
struct xlog_in_core *iclog = log->l_iclog;
xfs_lsn_t lowest_lsn = 0, lsn;
do {
if (iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY)
continue;
lsn = be64_to_cpu(iclog->ic_header.h_lsn);
if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0)
lowest_lsn = lsn;
} while ((iclog = iclog->ic_next) != log->l_iclog);
return lowest_lsn;
}
/*
* Completion of a iclog IO does not imply that a transaction has completed, as
* transactions can be large enough to span many iclogs. We cannot change the
* tail of the log half way through a transaction as this may be the only
* transaction in the log and moving the tail to point to the middle of it
* will prevent recovery from finding the start of the transaction. Hence we
* should only update the last_sync_lsn if this iclog contains transaction
* completion callbacks on it.
*
* We have to do this before we drop the icloglock to ensure we are the only one
* that can update it.
*
* If we are moving the last_sync_lsn forwards, we also need to ensure we kick
* the reservation grant head pushing. This is due to the fact that the push
* target is bound by the current last_sync_lsn value. Hence if we have a large
* amount of log space bound up in this committing transaction then the
* last_sync_lsn value may be the limiting factor preventing tail pushing from
* freeing space in the log. Hence once we've updated the last_sync_lsn we
* should push the AIL to ensure the push target (and hence the grant head) is
* no longer bound by the old log head location and can move forwards and make
* progress again.
*/
static void
xlog_state_set_callback(
struct xlog *log,
struct xlog_in_core *iclog,
xfs_lsn_t header_lsn)
{
trace_xlog_iclog_callback(iclog, _RET_IP_);
iclog->ic_state = XLOG_STATE_CALLBACK;
ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
header_lsn) <= 0);
if (list_empty_careful(&iclog->ic_callbacks))
return;
atomic64_set(&log->l_last_sync_lsn, header_lsn);
xlog_grant_push_ail(log, 0);
}
/*
* Return true if we need to stop processing, false to continue to the next
* iclog. The caller will need to run callbacks if the iclog is returned in the
* XLOG_STATE_CALLBACK state.
*/
static bool
xlog_state_iodone_process_iclog(
struct xlog *log,
struct xlog_in_core *iclog)
{
xfs_lsn_t lowest_lsn;
xfs_lsn_t header_lsn;
switch (iclog->ic_state) {
case XLOG_STATE_ACTIVE:
case XLOG_STATE_DIRTY:
/*
* Skip all iclogs in the ACTIVE & DIRTY states:
*/
return false;
case XLOG_STATE_DONE_SYNC:
/*
* Now that we have an iclog that is in the DONE_SYNC state, do
* one more check here to see if we have chased our tail around.
* If this is not the lowest lsn iclog, then we will leave it
* for another completion to process.
*/
header_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
lowest_lsn = xlog_get_lowest_lsn(log);
if (lowest_lsn && XFS_LSN_CMP(lowest_lsn, header_lsn) < 0)
return false;
xlog_state_set_callback(log, iclog, header_lsn);
return false;
default:
/*
* Can only perform callbacks in order. Since this iclog is not
* in the DONE_SYNC state, we skip the rest and just try to
* clean up.
*/
return true;
}
}
/*
* Loop over all the iclogs, running attached callbacks on them. Return true if
* we ran any callbacks, indicating that we dropped the icloglock. We don't need
* to handle transient shutdown state here at all because
* xlog_state_shutdown_callbacks() will be run to do the necessary shutdown
* cleanup of the callbacks.
*/
static bool
xlog_state_do_iclog_callbacks(
struct xlog *log)
__releases(&log->l_icloglock)
__acquires(&log->l_icloglock)
{
struct xlog_in_core *first_iclog = log->l_iclog;
struct xlog_in_core *iclog = first_iclog;
bool ran_callback = false;
do {
LIST_HEAD(cb_list);
if (xlog_state_iodone_process_iclog(log, iclog))
break;
if (iclog->ic_state != XLOG_STATE_CALLBACK) {
iclog = iclog->ic_next;
continue;
}
list_splice_init(&iclog->ic_callbacks, &cb_list);
spin_unlock(&log->l_icloglock);
trace_xlog_iclog_callbacks_start(iclog, _RET_IP_);
xlog_cil_process_committed(&cb_list);
trace_xlog_iclog_callbacks_done(iclog, _RET_IP_);
ran_callback = true;
spin_lock(&log->l_icloglock);
xlog_state_clean_iclog(log, iclog);
iclog = iclog->ic_next;
} while (iclog != first_iclog);
return ran_callback;
}
/*
* Loop running iclog completion callbacks until there are no more iclogs in a
* state that can run callbacks.
*/
STATIC void
xlog_state_do_callback(
struct xlog *log)
{
int flushcnt = 0;
int repeats = 0;
spin_lock(&log->l_icloglock);
while (xlog_state_do_iclog_callbacks(log)) {
if (xlog_is_shutdown(log))
break;
if (++repeats > 5000) {
flushcnt += repeats;
repeats = 0;
xfs_warn(log->l_mp,
"%s: possible infinite loop (%d iterations)",
__func__, flushcnt);
}
}
if (log->l_iclog->ic_state == XLOG_STATE_ACTIVE)
wake_up_all(&log->l_flush_wait);
spin_unlock(&log->l_icloglock);
}
/*
* Finish transitioning this iclog to the dirty state.
*
* Callbacks could take time, so they are done outside the scope of the
* global state machine log lock.
*/
STATIC void
xlog_state_done_syncing(
struct xlog_in_core *iclog)
{
struct xlog *log = iclog->ic_log;
spin_lock(&log->l_icloglock);
ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
trace_xlog_iclog_sync_done(iclog, _RET_IP_);
/*
* If we got an error, either on the first buffer, or in the case of
* split log writes, on the second, we shut down the file system and
* no iclogs should ever be attempted to be written to disk again.
*/
if (!xlog_is_shutdown(log)) {
ASSERT(iclog->ic_state == XLOG_STATE_SYNCING);
iclog->ic_state = XLOG_STATE_DONE_SYNC;
}
/*
* Someone could be sleeping prior to writing out the next
* iclog buffer, we wake them all, one will get to do the
* I/O, the others get to wait for the result.
*/
wake_up_all(&iclog->ic_write_wait);
spin_unlock(&log->l_icloglock);
xlog_state_do_callback(log);
}
/*
* If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
* sleep. We wait on the flush queue on the head iclog as that should be
* the first iclog to complete flushing. Hence if all iclogs are syncing,
* we will wait here and all new writes will sleep until a sync completes.
*
* The in-core logs are used in a circular fashion. They are not used
* out-of-order even when an iclog past the head is free.
*
* return:
* * log_offset where xlog_write() can start writing into the in-core
* log's data space.
* * in-core log pointer to which xlog_write() should write.
* * boolean indicating this is a continued write to an in-core log.
* If this is the last write, then the in-core log's offset field
* needs to be incremented, depending on the amount of data which
* is copied.
*/
STATIC int
xlog_state_get_iclog_space(
struct xlog *log,
int len,
struct xlog_in_core **iclogp,
struct xlog_ticket *ticket,
int *logoffsetp)
{
int log_offset;
xlog_rec_header_t *head;
xlog_in_core_t *iclog;
restart:
spin_lock(&log->l_icloglock);
if (xlog_is_shutdown(log)) {
spin_unlock(&log->l_icloglock);
return -EIO;
}
iclog = log->l_iclog;
if (iclog->ic_state != XLOG_STATE_ACTIVE) {
XFS_STATS_INC(log->l_mp, xs_log_noiclogs);
/* Wait for log writes to have flushed */
xlog_wait(&log->l_flush_wait, &log->l_icloglock);
goto restart;
}
head = &iclog->ic_header;
atomic_inc(&iclog->ic_refcnt); /* prevents sync */
log_offset = iclog->ic_offset;
trace_xlog_iclog_get_space(iclog, _RET_IP_);
/* On the 1st write to an iclog, figure out lsn. This works
* if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
* committing to. If the offset is set, that's how many blocks
* must be written.
*/
if (log_offset == 0) {
ticket->t_curr_res -= log->l_iclog_hsize;
head->h_cycle = cpu_to_be32(log->l_curr_cycle);
head->h_lsn = cpu_to_be64(
xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
ASSERT(log->l_curr_block >= 0);
}
/* If there is enough room to write everything, then do it. Otherwise,
* claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
* bit is on, so this will get flushed out. Don't update ic_offset
* until you know exactly how many bytes get copied. Therefore, wait
* until later to update ic_offset.
*
* xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
* can fit into remaining data section.
*/
if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
int error = 0;
xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
/*
* If we are the only one writing to this iclog, sync it to
* disk. We need to do an atomic compare and decrement here to
* avoid racing with concurrent atomic_dec_and_lock() calls in
* xlog_state_release_iclog() when there is more than one
* reference to the iclog.
*/
if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1))
error = xlog_state_release_iclog(log, iclog, ticket);
spin_unlock(&log->l_icloglock);
if (error)
return error;
goto restart;
}
/* Do we have enough room to write the full amount in the remainder
* of this iclog? Or must we continue a write on the next iclog and
* mark this iclog as completely taken? In the case where we switch
* iclogs (to mark it taken), this particular iclog will release/sync
* to disk in xlog_write().
*/
if (len <= iclog->ic_size - iclog->ic_offset)
iclog->ic_offset += len;
else
xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
*iclogp = iclog;
ASSERT(iclog->ic_offset <= iclog->ic_size);
spin_unlock(&log->l_icloglock);
*logoffsetp = log_offset;
return 0;
}
/*
* The first cnt-1 times a ticket goes through here we don't need to move the
* grant write head because the permanent reservation has reserved cnt times the
* unit amount. Release part of current permanent unit reservation and reset
* current reservation to be one units worth. Also move grant reservation head
* forward.
*/
void
xfs_log_ticket_regrant(
struct xlog *log,
struct xlog_ticket *ticket)
{
trace_xfs_log_ticket_regrant(log, ticket);
if (ticket->t_cnt > 0)
ticket->t_cnt--;
xlog_grant_sub_space(log, &log->l_reserve_head.grant,
ticket->t_curr_res);
xlog_grant_sub_space(log, &log->l_write_head.grant,
ticket->t_curr_res);
ticket->t_curr_res = ticket->t_unit_res;
trace_xfs_log_ticket_regrant_sub(log, ticket);
/* just return if we still have some of the pre-reserved space */
if (!ticket->t_cnt) {
xlog_grant_add_space(log, &log->l_reserve_head.grant,
ticket->t_unit_res);
trace_xfs_log_ticket_regrant_exit(log, ticket);
ticket->t_curr_res = ticket->t_unit_res;
}
xfs_log_ticket_put(ticket);
}
/*
* Give back the space left from a reservation.
*
* All the information we need to make a correct determination of space left
* is present. For non-permanent reservations, things are quite easy. The
* count should have been decremented to zero. We only need to deal with the
* space remaining in the current reservation part of the ticket. If the
* ticket contains a permanent reservation, there may be left over space which
* needs to be released. A count of N means that N-1 refills of the current
* reservation can be done before we need to ask for more space. The first
* one goes to fill up the first current reservation. Once we run out of
* space, the count will stay at zero and the only space remaining will be
* in the current reservation field.
*/
void
xfs_log_ticket_ungrant(
struct xlog *log,
struct xlog_ticket *ticket)
{
int bytes;
trace_xfs_log_ticket_ungrant(log, ticket);
if (ticket->t_cnt > 0)
ticket->t_cnt--;
trace_xfs_log_ticket_ungrant_sub(log, ticket);
/*
* If this is a permanent reservation ticket, we may be able to free
* up more space based on the remaining count.
*/
bytes = ticket->t_curr_res;
if (ticket->t_cnt > 0) {
ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
bytes += ticket->t_unit_res*ticket->t_cnt;
}
xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes);
xlog_grant_sub_space(log, &log->l_write_head.grant, bytes);
trace_xfs_log_ticket_ungrant_exit(log, ticket);
xfs_log_space_wake(log->l_mp);
xfs_log_ticket_put(ticket);
}
/*
* This routine will mark the current iclog in the ring as WANT_SYNC and move
* the current iclog pointer to the next iclog in the ring.
*/
void
xlog_state_switch_iclogs(
struct xlog *log,
struct xlog_in_core *iclog,
int eventual_size)
{
ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
assert_spin_locked(&log->l_icloglock);
trace_xlog_iclog_switch(iclog, _RET_IP_);
if (!eventual_size)
eventual_size = iclog->ic_offset;
iclog->ic_state = XLOG_STATE_WANT_SYNC;
iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
log->l_prev_block = log->l_curr_block;
log->l_prev_cycle = log->l_curr_cycle;
/* roll log?: ic_offset changed later */
log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
/* Round up to next log-sunit */
if (log->l_iclog_roundoff > BBSIZE) {
uint32_t sunit_bb = BTOBB(log->l_iclog_roundoff);
log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
}
if (log->l_curr_block >= log->l_logBBsize) {
/*
* Rewind the current block before the cycle is bumped to make
* sure that the combined LSN never transiently moves forward
* when the log wraps to the next cycle. This is to support the
* unlocked sample of these fields from xlog_valid_lsn(). Most
* other cases should acquire l_icloglock.
*/
log->l_curr_block -= log->l_logBBsize;
ASSERT(log->l_curr_block >= 0);
smp_wmb();
log->l_curr_cycle++;
if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
log->l_curr_cycle++;
}
ASSERT(iclog == log->l_iclog);
log->l_iclog = iclog->ic_next;
}
/*
* Force the iclog to disk and check if the iclog has been completed before
* xlog_force_iclog() returns. This can happen on synchronous (e.g.
* pmem) or fast async storage because we drop the icloglock to issue the IO.
* If completion has already occurred, tell the caller so that it can avoid an
* unnecessary wait on the iclog.
*/
static int
xlog_force_and_check_iclog(
struct xlog_in_core *iclog,
bool *completed)
{
xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn);
int error;
*completed = false;
error = xlog_force_iclog(iclog);
if (error)
return error;
/*
* If the iclog has already been completed and reused the header LSN
* will have been rewritten by completion
*/
if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn)
*completed = true;
return 0;
}
/*
* Write out all data in the in-core log as of this exact moment in time.
*
* Data may be written to the in-core log during this call. However,
* we don't guarantee this data will be written out. A change from past
* implementation means this routine will *not* write out zero length LRs.
*
* Basically, we try and perform an intelligent scan of the in-core logs.
* If we determine there is no flushable data, we just return. There is no
* flushable data if:
*
* 1. the current iclog is active and has no data; the previous iclog
* is in the active or dirty state.
* 2. the current iclog is drity, and the previous iclog is in the
* active or dirty state.
*
* We may sleep if:
*
* 1. the current iclog is not in the active nor dirty state.
* 2. the current iclog dirty, and the previous iclog is not in the
* active nor dirty state.
* 3. the current iclog is active, and there is another thread writing
* to this particular iclog.
* 4. a) the current iclog is active and has no other writers
* b) when we return from flushing out this iclog, it is still
* not in the active nor dirty state.
*/
int
xfs_log_force(
struct xfs_mount *mp,
uint flags)
{
struct xlog *log = mp->m_log;
struct xlog_in_core *iclog;
XFS_STATS_INC(mp, xs_log_force);
trace_xfs_log_force(mp, 0, _RET_IP_);
xlog_cil_force(log);
spin_lock(&log->l_icloglock);
if (xlog_is_shutdown(log))
goto out_error;
iclog = log->l_iclog;
trace_xlog_iclog_force(iclog, _RET_IP_);
if (iclog->ic_state == XLOG_STATE_DIRTY ||
(iclog->ic_state == XLOG_STATE_ACTIVE &&
atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) {
/*
* If the head is dirty or (active and empty), then we need to
* look at the previous iclog.
*
* If the previous iclog is active or dirty we are done. There
* is nothing to sync out. Otherwise, we attach ourselves to the
* previous iclog and go to sleep.
*/
iclog = iclog->ic_prev;
} else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
if (atomic_read(&iclog->ic_refcnt) == 0) {
/* We have exclusive access to this iclog. */
bool completed;
if (xlog_force_and_check_iclog(iclog, &completed))
goto out_error;
if (completed)
goto out_unlock;
} else {
/*
* Someone else is still writing to this iclog, so we
* need to ensure that when they release the iclog it
* gets synced immediately as we may be waiting on it.
*/
xlog_state_switch_iclogs(log, iclog, 0);
}
}
/*
* The iclog we are about to wait on may contain the checkpoint pushed
* by the above xlog_cil_force() call, but it may not have been pushed
* to disk yet. Like the ACTIVE case above, we need to make sure caches
* are flushed when this iclog is written.
*/
if (iclog->ic_state == XLOG_STATE_WANT_SYNC)
iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
if (flags & XFS_LOG_SYNC)
return xlog_wait_on_iclog(iclog);
out_unlock:
spin_unlock(&log->l_icloglock);
return 0;
out_error:
spin_unlock(&log->l_icloglock);
return -EIO;
}
/*
* Force the log to a specific LSN.
*
* If an iclog with that lsn can be found:
* If it is in the DIRTY state, just return.
* If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
* state and go to sleep or return.
* If it is in any other state, go to sleep or return.
*
* Synchronous forces are implemented with a wait queue. All callers trying
* to force a given lsn to disk must wait on the queue attached to the
* specific in-core log. When given in-core log finally completes its write
* to disk, that thread will wake up all threads waiting on the queue.
*/
static int
xlog_force_lsn(
struct xlog *log,
xfs_lsn_t lsn,
uint flags,
int *log_flushed,
bool already_slept)
{
struct xlog_in_core *iclog;
bool completed;
spin_lock(&log->l_icloglock);
if (xlog_is_shutdown(log))
goto out_error;
iclog = log->l_iclog;
while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
trace_xlog_iclog_force_lsn(iclog, _RET_IP_);
iclog = iclog->ic_next;
if (iclog == log->l_iclog)
goto out_unlock;
}
switch (iclog->ic_state) {
case XLOG_STATE_ACTIVE:
/*
* We sleep here if we haven't already slept (e.g. this is the
* first time we've looked at the correct iclog buf) and the
* buffer before us is going to be sync'ed. The reason for this
* is that if we are doing sync transactions here, by waiting
* for the previous I/O to complete, we can allow a few more
* transactions into this iclog before we close it down.
*
* Otherwise, we mark the buffer WANT_SYNC, and bump up the
* refcnt so we can release the log (which drops the ref count).
* The state switch keeps new transaction commits from using
* this buffer. When the current commits finish writing into
* the buffer, the refcount will drop to zero and the buffer
* will go out then.
*/
if (!already_slept &&
(iclog->ic_prev->ic_state == XLOG_STATE_WANT_SYNC ||
iclog->ic_prev->ic_state == XLOG_STATE_SYNCING)) {
xlog_wait(&iclog->ic_prev->ic_write_wait,
&log->l_icloglock);
return -EAGAIN;
}
if (xlog_force_and_check_iclog(iclog, &completed))
goto out_error;
if (log_flushed)
*log_flushed = 1;
if (completed)
goto out_unlock;
break;
case XLOG_STATE_WANT_SYNC:
/*
* This iclog may contain the checkpoint pushed by the
* xlog_cil_force_seq() call, but there are other writers still
* accessing it so it hasn't been pushed to disk yet. Like the
* ACTIVE case above, we need to make sure caches are flushed
* when this iclog is written.
*/
iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA;
break;
default:
/*
* The entire checkpoint was written by the CIL force and is on
* its way to disk already. It will be stable when it
* completes, so we don't need to manipulate caches here at all.
* We just need to wait for completion if necessary.
*/
break;
}
if (flags & XFS_LOG_SYNC)
return xlog_wait_on_iclog(iclog);
out_unlock:
spin_unlock(&log->l_icloglock);
return 0;
out_error:
spin_unlock(&log->l_icloglock);
return -EIO;
}
/*
* Force the log to a specific checkpoint sequence.
*
* First force the CIL so that all the required changes have been flushed to the
* iclogs. If the CIL force completed it will return a commit LSN that indicates
* the iclog that needs to be flushed to stable storage. If the caller needs
* a synchronous log force, we will wait on the iclog with the LSN returned by
* xlog_cil_force_seq() to be completed.
*/
int
xfs_log_force_seq(
struct xfs_mount *mp,
xfs_csn_t seq,
uint flags,
int *log_flushed)
{
struct xlog *log = mp->m_log;
xfs_lsn_t lsn;
int ret;
ASSERT(seq != 0);
XFS_STATS_INC(mp, xs_log_force);
trace_xfs_log_force(mp, seq, _RET_IP_);
lsn = xlog_cil_force_seq(log, seq);
if (lsn == NULLCOMMITLSN)
return 0;
ret = xlog_force_lsn(log, lsn, flags, log_flushed, false);
if (ret == -EAGAIN) {
XFS_STATS_INC(mp, xs_log_force_sleep);
ret = xlog_force_lsn(log, lsn, flags, log_flushed, true);
}
return ret;
}
/*
* Free a used ticket when its refcount falls to zero.
*/
void
xfs_log_ticket_put(
xlog_ticket_t *ticket)
{
ASSERT(atomic_read(&ticket->t_ref) > 0);
if (atomic_dec_and_test(&ticket->t_ref))
kmem_cache_free(xfs_log_ticket_cache, ticket);
}
xlog_ticket_t *
xfs_log_ticket_get(
xlog_ticket_t *ticket)
{
ASSERT(atomic_read(&ticket->t_ref) > 0);
atomic_inc(&ticket->t_ref);
return ticket;
}
/*
* Figure out the total log space unit (in bytes) that would be
* required for a log ticket.
*/
static int
xlog_calc_unit_res(
struct xlog *log,
int unit_bytes,
int *niclogs)
{
int iclog_space;
uint num_headers;
/*
* Permanent reservations have up to 'cnt'-1 active log operations
* in the log. A unit in this case is the amount of space for one
* of these log operations. Normal reservations have a cnt of 1
* and their unit amount is the total amount of space required.
*
* The following lines of code account for non-transaction data
* which occupy space in the on-disk log.
*
* Normal form of a transaction is:
* <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
* and then there are LR hdrs, split-recs and roundoff at end of syncs.
*
* We need to account for all the leadup data and trailer data
* around the transaction data.
* And then we need to account for the worst case in terms of using
* more space.
* The worst case will happen if:
* - the placement of the transaction happens to be such that the
* roundoff is at its maximum
* - the transaction data is synced before the commit record is synced
* i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
* Therefore the commit record is in its own Log Record.
* This can happen as the commit record is called with its
* own region to xlog_write().
* This then means that in the worst case, roundoff can happen for
* the commit-rec as well.
* The commit-rec is smaller than padding in this scenario and so it is
* not added separately.
*/
/* for trans header */
unit_bytes += sizeof(xlog_op_header_t);
unit_bytes += sizeof(xfs_trans_header_t);
/* for start-rec */
unit_bytes += sizeof(xlog_op_header_t);
/*
* for LR headers - the space for data in an iclog is the size minus
* the space used for the headers. If we use the iclog size, then we
* undercalculate the number of headers required.
*
* Furthermore - the addition of op headers for split-recs might
* increase the space required enough to require more log and op
* headers, so take that into account too.
*
* IMPORTANT: This reservation makes the assumption that if this
* transaction is the first in an iclog and hence has the LR headers
* accounted to it, then the remaining space in the iclog is
* exclusively for this transaction. i.e. if the transaction is larger
* than the iclog, it will be the only thing in that iclog.
* Fundamentally, this means we must pass the entire log vector to
* xlog_write to guarantee this.
*/
iclog_space = log->l_iclog_size - log->l_iclog_hsize;
num_headers = howmany(unit_bytes, iclog_space);
/* for split-recs - ophdrs added when data split over LRs */
unit_bytes += sizeof(xlog_op_header_t) * num_headers;
/* add extra header reservations if we overrun */
while (!num_headers ||
howmany(unit_bytes, iclog_space) > num_headers) {
unit_bytes += sizeof(xlog_op_header_t);
num_headers++;
}
unit_bytes += log->l_iclog_hsize * num_headers;
/* for commit-rec LR header - note: padding will subsume the ophdr */
unit_bytes += log->l_iclog_hsize;
/* roundoff padding for transaction data and one for commit record */
unit_bytes += 2 * log->l_iclog_roundoff;
if (niclogs)
*niclogs = num_headers;
return unit_bytes;
}
int
xfs_log_calc_unit_res(
struct xfs_mount *mp,
int unit_bytes)
{
return xlog_calc_unit_res(mp->m_log, unit_bytes, NULL);
}
/*
* Allocate and initialise a new log ticket.
*/
struct xlog_ticket *
xlog_ticket_alloc(
struct xlog *log,
int unit_bytes,
int cnt,
bool permanent)
{
struct xlog_ticket *tic;
int unit_res;
tic = kmem_cache_zalloc(xfs_log_ticket_cache, GFP_NOFS | __GFP_NOFAIL);
unit_res = xlog_calc_unit_res(log, unit_bytes, &tic->t_iclog_hdrs);
atomic_set(&tic->t_ref, 1);
tic->t_task = current;
INIT_LIST_HEAD(&tic->t_queue);
tic->t_unit_res = unit_res;
tic->t_curr_res = unit_res;
tic->t_cnt = cnt;
tic->t_ocnt = cnt;
tic->t_tid = get_random_u32();
if (permanent)
tic->t_flags |= XLOG_TIC_PERM_RESERV;
return tic;
}
#if defined(DEBUG)
/*
* Check to make sure the grant write head didn't just over lap the tail. If
* the cycles are the same, we can't be overlapping. Otherwise, make sure that
* the cycles differ by exactly one and check the byte count.
*
* This check is run unlocked, so can give false positives. Rather than assert
* on failures, use a warn-once flag and a panic tag to allow the admin to
* determine if they want to panic the machine when such an error occurs. For
* debug kernels this will have the same effect as using an assert but, unlinke
* an assert, it can be turned off at runtime.
*/
STATIC void
xlog_verify_grant_tail(
struct xlog *log)
{
int tail_cycle, tail_blocks;
int cycle, space;
xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space);
xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks);
if (tail_cycle != cycle) {
if (cycle - 1 != tail_cycle &&
!test_and_set_bit(XLOG_TAIL_WARN, &log->l_opstate)) {
xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
"%s: cycle - 1 != tail_cycle", __func__);
}
if (space > BBTOB(tail_blocks) &&
!test_and_set_bit(XLOG_TAIL_WARN, &log->l_opstate)) {
xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
"%s: space > BBTOB(tail_blocks)", __func__);
}
}
}
/* check if it will fit */
STATIC void
xlog_verify_tail_lsn(
struct xlog *log,
struct xlog_in_core *iclog)
{
xfs_lsn_t tail_lsn = be64_to_cpu(iclog->ic_header.h_tail_lsn);
int blocks;
if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
blocks =
log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
} else {
ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
xfs_emerg(log->l_mp, "%s: tail wrapped", __func__);
blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
if (blocks < BTOBB(iclog->ic_offset) + 1)
xfs_emerg(log->l_mp, "%s: ran out of log space", __func__);
}
}
/*
* Perform a number of checks on the iclog before writing to disk.
*
* 1. Make sure the iclogs are still circular
* 2. Make sure we have a good magic number
* 3. Make sure we don't have magic numbers in the data
* 4. Check fields of each log operation header for:
* A. Valid client identifier
* B. tid ptr value falls in valid ptr space (user space code)
* C. Length in log record header is correct according to the
* individual operation headers within record.
* 5. When a bwrite will occur within 5 blocks of the front of the physical
* log, check the preceding blocks of the physical log to make sure all
* the cycle numbers agree with the current cycle number.
*/
STATIC void
xlog_verify_iclog(
struct xlog *log,
struct xlog_in_core *iclog,
int count)
{
xlog_op_header_t *ophead;
xlog_in_core_t *icptr;
xlog_in_core_2_t *xhdr;
void *base_ptr, *ptr, *p;
ptrdiff_t field_offset;
uint8_t clientid;
int len, i, j, k, op_len;
int idx;
/* check validity of iclog pointers */
spin_lock(&log->l_icloglock);
icptr = log->l_iclog;
for (i = 0; i < log->l_iclog_bufs; i++, icptr = icptr->ic_next)
ASSERT(icptr);
if (icptr != log->l_iclog)
xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__);
spin_unlock(&log->l_icloglock);
/* check log magic numbers */
if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
xfs_emerg(log->l_mp, "%s: invalid magic num", __func__);
base_ptr = ptr = &iclog->ic_header;
p = &iclog->ic_header;
for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) {
if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
xfs_emerg(log->l_mp, "%s: unexpected magic num",
__func__);
}
/* check fields */
len = be32_to_cpu(iclog->ic_header.h_num_logops);
base_ptr = ptr = iclog->ic_datap;
ophead = ptr;
xhdr = iclog->ic_data;
for (i = 0; i < len; i++) {
ophead = ptr;
/* clientid is only 1 byte */
p = &ophead->oh_clientid;
field_offset = p - base_ptr;
if (field_offset & 0x1ff) {
clientid = ophead->oh_clientid;
} else {
idx = BTOBBT((void *)&ophead->oh_clientid - iclog->ic_datap);
if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
clientid = xlog_get_client_id(
xhdr[j].hic_xheader.xh_cycle_data[k]);
} else {
clientid = xlog_get_client_id(
iclog->ic_header.h_cycle_data[idx]);
}
}
if (clientid != XFS_TRANSACTION && clientid != XFS_LOG) {
xfs_warn(log->l_mp,
"%s: op %d invalid clientid %d op "PTR_FMT" offset 0x%lx",
__func__, i, clientid, ophead,
(unsigned long)field_offset);
}
/* check length */
p = &ophead->oh_len;
field_offset = p - base_ptr;
if (field_offset & 0x1ff) {
op_len = be32_to_cpu(ophead->oh_len);
} else {
idx = BTOBBT((void *)&ophead->oh_len - iclog->ic_datap);
if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
} else {
op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
}
}
ptr += sizeof(xlog_op_header_t) + op_len;
}
}
#endif
/*
* Perform a forced shutdown on the log.
*
* This can be called from low level log code to trigger a shutdown, or from the
* high level mount shutdown code when the mount shuts down.
*
* Our main objectives here are to make sure that:
* a. if the shutdown was not due to a log IO error, flush the logs to
* disk. Anything modified after this is ignored.
* b. the log gets atomically marked 'XLOG_IO_ERROR' for all interested
* parties to find out. Nothing new gets queued after this is done.
* c. Tasks sleeping on log reservations, pinned objects and
* other resources get woken up.
* d. The mount is also marked as shut down so that log triggered shutdowns
* still behave the same as if they called xfs_forced_shutdown().
*
* Return true if the shutdown cause was a log IO error and we actually shut the
* log down.
*/
bool
xlog_force_shutdown(
struct xlog *log,
uint32_t shutdown_flags)
{
bool log_error = (shutdown_flags & SHUTDOWN_LOG_IO_ERROR);
if (!log)
return false;
/*
* Flush all the completed transactions to disk before marking the log
* being shut down. We need to do this first as shutting down the log
* before the force will prevent the log force from flushing the iclogs
* to disk.
*
* When we are in recovery, there are no transactions to flush, and
* we don't want to touch the log because we don't want to perturb the
* current head/tail for future recovery attempts. Hence we need to
* avoid a log force in this case.
*
* If we are shutting down due to a log IO error, then we must avoid
* trying to write the log as that may just result in more IO errors and
* an endless shutdown/force loop.
*/
if (!log_error && !xlog_in_recovery(log))
xfs_log_force(log->l_mp, XFS_LOG_SYNC);
/*
* Atomically set the shutdown state. If the shutdown state is already
* set, there someone else is performing the shutdown and so we are done
* here. This should never happen because we should only ever get called
* once by the first shutdown caller.
*
* Much of the log state machine transitions assume that shutdown state
* cannot change once they hold the log->l_icloglock. Hence we need to
* hold that lock here, even though we use the atomic test_and_set_bit()
* operation to set the shutdown state.
*/
spin_lock(&log->l_icloglock);
if (test_and_set_bit(XLOG_IO_ERROR, &log->l_opstate)) {
spin_unlock(&log->l_icloglock);
return false;
}
spin_unlock(&log->l_icloglock);
/*
* If this log shutdown also sets the mount shutdown state, issue a
* shutdown warning message.
*/
if (!test_and_set_bit(XFS_OPSTATE_SHUTDOWN, &log->l_mp->m_opstate)) {
xfs_alert_tag(log->l_mp, XFS_PTAG_SHUTDOWN_LOGERROR,
"Filesystem has been shut down due to log error (0x%x).",
shutdown_flags);
xfs_alert(log->l_mp,
"Please unmount the filesystem and rectify the problem(s).");
if (xfs_error_level >= XFS_ERRLEVEL_HIGH)
xfs_stack_trace();
}
/*
* We don't want anybody waiting for log reservations after this. That
* means we have to wake up everybody queued up on reserveq as well as
* writeq. In addition, we make sure in xlog_{re}grant_log_space that
* we don't enqueue anything once the SHUTDOWN flag is set, and this
* action is protected by the grant locks.
*/
xlog_grant_head_wake_all(&log->l_reserve_head);
xlog_grant_head_wake_all(&log->l_write_head);
/*
* Wake up everybody waiting on xfs_log_force. Wake the CIL push first
* as if the log writes were completed. The abort handling in the log
* item committed callback functions will do this again under lock to
* avoid races.
*/
spin_lock(&log->l_cilp->xc_push_lock);
wake_up_all(&log->l_cilp->xc_start_wait);
wake_up_all(&log->l_cilp->xc_commit_wait);
spin_unlock(&log->l_cilp->xc_push_lock);
spin_lock(&log->l_icloglock);
xlog_state_shutdown_callbacks(log);
spin_unlock(&log->l_icloglock);
wake_up_var(&log->l_opstate);
return log_error;
}
STATIC int
xlog_iclogs_empty(
struct xlog *log)
{
xlog_in_core_t *iclog;
iclog = log->l_iclog;
do {
/* endianness does not matter here, zero is zero in
* any language.
*/
if (iclog->ic_header.h_num_logops)
return 0;
iclog = iclog->ic_next;
} while (iclog != log->l_iclog);
return 1;
}
/*
* Verify that an LSN stamped into a piece of metadata is valid. This is
* intended for use in read verifiers on v5 superblocks.
*/
bool
xfs_log_check_lsn(
struct xfs_mount *mp,
xfs_lsn_t lsn)
{
struct xlog *log = mp->m_log;
bool valid;
/*
* norecovery mode skips mount-time log processing and unconditionally
* resets the in-core LSN. We can't validate in this mode, but
* modifications are not allowed anyways so just return true.
*/
if (xfs_has_norecovery(mp))
return true;
/*
* Some metadata LSNs are initialized to NULL (e.g., the agfl). This is
* handled by recovery and thus safe to ignore here.
*/
if (lsn == NULLCOMMITLSN)
return true;
valid = xlog_valid_lsn(mp->m_log, lsn);
/* warn the user about what's gone wrong before verifier failure */
if (!valid) {
spin_lock(&log->l_icloglock);
xfs_warn(mp,
"Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). "
"Please unmount and run xfs_repair (>= v4.3) to resolve.",
CYCLE_LSN(lsn), BLOCK_LSN(lsn),
log->l_curr_cycle, log->l_curr_block);
spin_unlock(&log->l_icloglock);
}
return valid;
}
/*
* Notify the log that we're about to start using a feature that is protected
* by a log incompat feature flag. This will prevent log covering from
* clearing those flags.
*/
void
xlog_use_incompat_feat(
struct xlog *log)
{
down_read(&log->l_incompat_users);
}
/* Notify the log that we've finished using log incompat features. */
void
xlog_drop_incompat_feat(
struct xlog *log)
{
up_read(&log->l_incompat_users);
}
| linux-master | fs/xfs/xfs_log.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_buf_item.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_quota.h"
#include "xfs_dquot_item.h"
#include "xfs_dquot.h"
#include "xfs_trace.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
struct kmem_cache *xfs_buf_item_cache;
static inline struct xfs_buf_log_item *BUF_ITEM(struct xfs_log_item *lip)
{
return container_of(lip, struct xfs_buf_log_item, bli_item);
}
/* Is this log iovec plausibly large enough to contain the buffer log format? */
bool
xfs_buf_log_check_iovec(
struct xfs_log_iovec *iovec)
{
struct xfs_buf_log_format *blfp = iovec->i_addr;
char *bmp_end;
char *item_end;
if (offsetof(struct xfs_buf_log_format, blf_data_map) > iovec->i_len)
return false;
item_end = (char *)iovec->i_addr + iovec->i_len;
bmp_end = (char *)&blfp->blf_data_map[blfp->blf_map_size];
return bmp_end <= item_end;
}
static inline int
xfs_buf_log_format_size(
struct xfs_buf_log_format *blfp)
{
return offsetof(struct xfs_buf_log_format, blf_data_map) +
(blfp->blf_map_size * sizeof(blfp->blf_data_map[0]));
}
static inline bool
xfs_buf_item_straddle(
struct xfs_buf *bp,
uint offset,
int first_bit,
int nbits)
{
void *first, *last;
first = xfs_buf_offset(bp, offset + (first_bit << XFS_BLF_SHIFT));
last = xfs_buf_offset(bp,
offset + ((first_bit + nbits) << XFS_BLF_SHIFT));
if (last - first != nbits * XFS_BLF_CHUNK)
return true;
return false;
}
/*
* Return the number of log iovecs and space needed to log the given buf log
* item segment.
*
* It calculates this as 1 iovec for the buf log format structure and 1 for each
* stretch of non-contiguous chunks to be logged. Contiguous chunks are logged
* in a single iovec.
*/
STATIC void
xfs_buf_item_size_segment(
struct xfs_buf_log_item *bip,
struct xfs_buf_log_format *blfp,
uint offset,
int *nvecs,
int *nbytes)
{
struct xfs_buf *bp = bip->bli_buf;
int first_bit;
int nbits;
int next_bit;
int last_bit;
first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
if (first_bit == -1)
return;
(*nvecs)++;
*nbytes += xfs_buf_log_format_size(blfp);
do {
nbits = xfs_contig_bits(blfp->blf_data_map,
blfp->blf_map_size, first_bit);
ASSERT(nbits > 0);
/*
* Straddling a page is rare because we don't log contiguous
* chunks of unmapped buffers anywhere.
*/
if (nbits > 1 &&
xfs_buf_item_straddle(bp, offset, first_bit, nbits))
goto slow_scan;
(*nvecs)++;
*nbytes += nbits * XFS_BLF_CHUNK;
/*
* This takes the bit number to start looking from and
* returns the next set bit from there. It returns -1
* if there are no more bits set or the start bit is
* beyond the end of the bitmap.
*/
first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
(uint)first_bit + nbits + 1);
} while (first_bit != -1);
return;
slow_scan:
/* Count the first bit we jumped out of the above loop from */
(*nvecs)++;
*nbytes += XFS_BLF_CHUNK;
last_bit = first_bit;
while (last_bit != -1) {
/*
* This takes the bit number to start looking from and
* returns the next set bit from there. It returns -1
* if there are no more bits set or the start bit is
* beyond the end of the bitmap.
*/
next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
last_bit + 1);
/*
* If we run out of bits, leave the loop,
* else if we find a new set of bits bump the number of vecs,
* else keep scanning the current set of bits.
*/
if (next_bit == -1) {
break;
} else if (next_bit != last_bit + 1 ||
xfs_buf_item_straddle(bp, offset, first_bit, nbits)) {
last_bit = next_bit;
first_bit = next_bit;
(*nvecs)++;
nbits = 1;
} else {
last_bit++;
nbits++;
}
*nbytes += XFS_BLF_CHUNK;
}
}
/*
* Return the number of log iovecs and space needed to log the given buf log
* item.
*
* Discontiguous buffers need a format structure per region that is being
* logged. This makes the changes in the buffer appear to log recovery as though
* they came from separate buffers, just like would occur if multiple buffers
* were used instead of a single discontiguous buffer. This enables
* discontiguous buffers to be in-memory constructs, completely transparent to
* what ends up on disk.
*
* If the XFS_BLI_STALE flag has been set, then log nothing but the buf log
* format structures. If the item has previously been logged and has dirty
* regions, we do not relog them in stale buffers. This has the effect of
* reducing the size of the relogged item by the amount of dirty data tracked
* by the log item. This can result in the committing transaction reducing the
* amount of space being consumed by the CIL.
*/
STATIC void
xfs_buf_item_size(
struct xfs_log_item *lip,
int *nvecs,
int *nbytes)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
struct xfs_buf *bp = bip->bli_buf;
int i;
int bytes;
uint offset = 0;
ASSERT(atomic_read(&bip->bli_refcount) > 0);
if (bip->bli_flags & XFS_BLI_STALE) {
/*
* The buffer is stale, so all we need to log is the buf log
* format structure with the cancel flag in it as we are never
* going to replay the changes tracked in the log item.
*/
trace_xfs_buf_item_size_stale(bip);
ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
*nvecs += bip->bli_format_count;
for (i = 0; i < bip->bli_format_count; i++) {
*nbytes += xfs_buf_log_format_size(&bip->bli_formats[i]);
}
return;
}
ASSERT(bip->bli_flags & XFS_BLI_LOGGED);
if (bip->bli_flags & XFS_BLI_ORDERED) {
/*
* The buffer has been logged just to order it. It is not being
* included in the transaction commit, so no vectors are used at
* all.
*/
trace_xfs_buf_item_size_ordered(bip);
*nvecs = XFS_LOG_VEC_ORDERED;
return;
}
/*
* The vector count is based on the number of buffer vectors we have
* dirty bits in. This will only be greater than one when we have a
* compound buffer with more than one segment dirty. Hence for compound
* buffers we need to track which segment the dirty bits correspond to,
* and when we move from one segment to the next increment the vector
* count for the extra buf log format structure that will need to be
* written.
*/
bytes = 0;
for (i = 0; i < bip->bli_format_count; i++) {
xfs_buf_item_size_segment(bip, &bip->bli_formats[i], offset,
nvecs, &bytes);
offset += BBTOB(bp->b_maps[i].bm_len);
}
/*
* Round up the buffer size required to minimise the number of memory
* allocations that need to be done as this item grows when relogged by
* repeated modifications.
*/
*nbytes = round_up(bytes, 512);
trace_xfs_buf_item_size(bip);
}
static inline void
xfs_buf_item_copy_iovec(
struct xfs_log_vec *lv,
struct xfs_log_iovec **vecp,
struct xfs_buf *bp,
uint offset,
int first_bit,
uint nbits)
{
offset += first_bit * XFS_BLF_CHUNK;
xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_BCHUNK,
xfs_buf_offset(bp, offset),
nbits * XFS_BLF_CHUNK);
}
static void
xfs_buf_item_format_segment(
struct xfs_buf_log_item *bip,
struct xfs_log_vec *lv,
struct xfs_log_iovec **vecp,
uint offset,
struct xfs_buf_log_format *blfp)
{
struct xfs_buf *bp = bip->bli_buf;
uint base_size;
int first_bit;
int last_bit;
int next_bit;
uint nbits;
/* copy the flags across from the base format item */
blfp->blf_flags = bip->__bli_format.blf_flags;
/*
* Base size is the actual size of the ondisk structure - it reflects
* the actual size of the dirty bitmap rather than the size of the in
* memory structure.
*/
base_size = xfs_buf_log_format_size(blfp);
first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size, 0);
if (!(bip->bli_flags & XFS_BLI_STALE) && first_bit == -1) {
/*
* If the map is not be dirty in the transaction, mark
* the size as zero and do not advance the vector pointer.
*/
return;
}
blfp = xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_BFORMAT, blfp, base_size);
blfp->blf_size = 1;
if (bip->bli_flags & XFS_BLI_STALE) {
/*
* The buffer is stale, so all we need to log
* is the buf log format structure with the
* cancel flag in it.
*/
trace_xfs_buf_item_format_stale(bip);
ASSERT(blfp->blf_flags & XFS_BLF_CANCEL);
return;
}
/*
* Fill in an iovec for each set of contiguous chunks.
*/
do {
ASSERT(first_bit >= 0);
nbits = xfs_contig_bits(blfp->blf_data_map,
blfp->blf_map_size, first_bit);
ASSERT(nbits > 0);
/*
* Straddling a page is rare because we don't log contiguous
* chunks of unmapped buffers anywhere.
*/
if (nbits > 1 &&
xfs_buf_item_straddle(bp, offset, first_bit, nbits))
goto slow_scan;
xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
first_bit, nbits);
blfp->blf_size++;
/*
* This takes the bit number to start looking from and
* returns the next set bit from there. It returns -1
* if there are no more bits set or the start bit is
* beyond the end of the bitmap.
*/
first_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
(uint)first_bit + nbits + 1);
} while (first_bit != -1);
return;
slow_scan:
ASSERT(bp->b_addr == NULL);
last_bit = first_bit;
nbits = 1;
for (;;) {
/*
* This takes the bit number to start looking from and
* returns the next set bit from there. It returns -1
* if there are no more bits set or the start bit is
* beyond the end of the bitmap.
*/
next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
(uint)last_bit + 1);
/*
* If we run out of bits fill in the last iovec and get out of
* the loop. Else if we start a new set of bits then fill in
* the iovec for the series we were looking at and start
* counting the bits in the new one. Else we're still in the
* same set of bits so just keep counting and scanning.
*/
if (next_bit == -1) {
xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
first_bit, nbits);
blfp->blf_size++;
break;
} else if (next_bit != last_bit + 1 ||
xfs_buf_item_straddle(bp, offset, first_bit, nbits)) {
xfs_buf_item_copy_iovec(lv, vecp, bp, offset,
first_bit, nbits);
blfp->blf_size++;
first_bit = next_bit;
last_bit = next_bit;
nbits = 1;
} else {
last_bit++;
nbits++;
}
}
}
/*
* This is called to fill in the vector of log iovecs for the
* given log buf item. It fills the first entry with a buf log
* format structure, and the rest point to contiguous chunks
* within the buffer.
*/
STATIC void
xfs_buf_item_format(
struct xfs_log_item *lip,
struct xfs_log_vec *lv)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
struct xfs_buf *bp = bip->bli_buf;
struct xfs_log_iovec *vecp = NULL;
uint offset = 0;
int i;
ASSERT(atomic_read(&bip->bli_refcount) > 0);
ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
(bip->bli_flags & XFS_BLI_STALE));
ASSERT((bip->bli_flags & XFS_BLI_STALE) ||
(xfs_blft_from_flags(&bip->__bli_format) > XFS_BLFT_UNKNOWN_BUF
&& xfs_blft_from_flags(&bip->__bli_format) < XFS_BLFT_MAX_BUF));
ASSERT(!(bip->bli_flags & XFS_BLI_ORDERED) ||
(bip->bli_flags & XFS_BLI_STALE));
/*
* If it is an inode buffer, transfer the in-memory state to the
* format flags and clear the in-memory state.
*
* For buffer based inode allocation, we do not transfer
* this state if the inode buffer allocation has not yet been committed
* to the log as setting the XFS_BLI_INODE_BUF flag will prevent
* correct replay of the inode allocation.
*
* For icreate item based inode allocation, the buffers aren't written
* to the journal during allocation, and hence we should always tag the
* buffer as an inode buffer so that the correct unlinked list replay
* occurs during recovery.
*/
if (bip->bli_flags & XFS_BLI_INODE_BUF) {
if (xfs_has_v3inodes(lip->li_log->l_mp) ||
!((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) &&
xfs_log_item_in_current_chkpt(lip)))
bip->__bli_format.blf_flags |= XFS_BLF_INODE_BUF;
bip->bli_flags &= ~XFS_BLI_INODE_BUF;
}
for (i = 0; i < bip->bli_format_count; i++) {
xfs_buf_item_format_segment(bip, lv, &vecp, offset,
&bip->bli_formats[i]);
offset += BBTOB(bp->b_maps[i].bm_len);
}
/*
* Check to make sure everything is consistent.
*/
trace_xfs_buf_item_format(bip);
}
/*
* This is called to pin the buffer associated with the buf log item in memory
* so it cannot be written out.
*
* We take a reference to the buffer log item here so that the BLI life cycle
* extends at least until the buffer is unpinned via xfs_buf_item_unpin() and
* inserted into the AIL.
*
* We also need to take a reference to the buffer itself as the BLI unpin
* processing requires accessing the buffer after the BLI has dropped the final
* BLI reference. See xfs_buf_item_unpin() for an explanation.
* If unpins race to drop the final BLI reference and only the
* BLI owns a reference to the buffer, then the loser of the race can have the
* buffer fgreed from under it (e.g. on shutdown). Taking a buffer reference per
* pin count ensures the life cycle of the buffer extends for as
* long as we hold the buffer pin reference in xfs_buf_item_unpin().
*/
STATIC void
xfs_buf_item_pin(
struct xfs_log_item *lip)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
ASSERT(atomic_read(&bip->bli_refcount) > 0);
ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
(bip->bli_flags & XFS_BLI_ORDERED) ||
(bip->bli_flags & XFS_BLI_STALE));
trace_xfs_buf_item_pin(bip);
xfs_buf_hold(bip->bli_buf);
atomic_inc(&bip->bli_refcount);
atomic_inc(&bip->bli_buf->b_pin_count);
}
/*
* This is called to unpin the buffer associated with the buf log item which was
* previously pinned with a call to xfs_buf_item_pin(). We enter this function
* with a buffer pin count, a buffer reference and a BLI reference.
*
* We must drop the BLI reference before we unpin the buffer because the AIL
* doesn't acquire a BLI reference whenever it accesses it. Therefore if the
* refcount drops to zero, the bli could still be AIL resident and the buffer
* submitted for I/O at any point before we return. This can result in IO
* completion freeing the buffer while we are still trying to access it here.
* This race condition can also occur in shutdown situations where we abort and
* unpin buffers from contexts other that journal IO completion.
*
* Hence we have to hold a buffer reference per pin count to ensure that the
* buffer cannot be freed until we have finished processing the unpin operation.
* The reference is taken in xfs_buf_item_pin(), and we must hold it until we
* are done processing the buffer state. In the case of an abort (remove =
* true) then we re-use the current pin reference as the IO reference we hand
* off to IO failure handling.
*/
STATIC void
xfs_buf_item_unpin(
struct xfs_log_item *lip,
int remove)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
struct xfs_buf *bp = bip->bli_buf;
int stale = bip->bli_flags & XFS_BLI_STALE;
int freed;
ASSERT(bp->b_log_item == bip);
ASSERT(atomic_read(&bip->bli_refcount) > 0);
trace_xfs_buf_item_unpin(bip);
freed = atomic_dec_and_test(&bip->bli_refcount);
if (atomic_dec_and_test(&bp->b_pin_count))
wake_up_all(&bp->b_waiters);
/*
* Nothing to do but drop the buffer pin reference if the BLI is
* still active.
*/
if (!freed) {
xfs_buf_rele(bp);
return;
}
if (stale) {
ASSERT(bip->bli_flags & XFS_BLI_STALE);
ASSERT(xfs_buf_islocked(bp));
ASSERT(bp->b_flags & XBF_STALE);
ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);
ASSERT(list_empty(&lip->li_trans));
ASSERT(!bp->b_transp);
trace_xfs_buf_item_unpin_stale(bip);
/*
* The buffer has been locked and referenced since it was marked
* stale so we own both lock and reference exclusively here. We
* do not need the pin reference any more, so drop it now so
* that we only have one reference to drop once item completion
* processing is complete.
*/
xfs_buf_rele(bp);
/*
* If we get called here because of an IO error, we may or may
* not have the item on the AIL. xfs_trans_ail_delete() will
* take care of that situation. xfs_trans_ail_delete() drops
* the AIL lock.
*/
if (bip->bli_flags & XFS_BLI_STALE_INODE) {
xfs_buf_item_done(bp);
xfs_buf_inode_iodone(bp);
ASSERT(list_empty(&bp->b_li_list));
} else {
xfs_trans_ail_delete(lip, SHUTDOWN_LOG_IO_ERROR);
xfs_buf_item_relse(bp);
ASSERT(bp->b_log_item == NULL);
}
xfs_buf_relse(bp);
return;
}
if (remove) {
/*
* We need to simulate an async IO failures here to ensure that
* the correct error completion is run on this buffer. This
* requires a reference to the buffer and for the buffer to be
* locked. We can safely pass ownership of the pin reference to
* the IO to ensure that nothing can free the buffer while we
* wait for the lock and then run the IO failure completion.
*/
xfs_buf_lock(bp);
bp->b_flags |= XBF_ASYNC;
xfs_buf_ioend_fail(bp);
return;
}
/*
* BLI has no more active references - it will be moved to the AIL to
* manage the remaining BLI/buffer life cycle. There is nothing left for
* us to do here so drop the pin reference to the buffer.
*/
xfs_buf_rele(bp);
}
STATIC uint
xfs_buf_item_push(
struct xfs_log_item *lip,
struct list_head *buffer_list)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
struct xfs_buf *bp = bip->bli_buf;
uint rval = XFS_ITEM_SUCCESS;
if (xfs_buf_ispinned(bp))
return XFS_ITEM_PINNED;
if (!xfs_buf_trylock(bp)) {
/*
* If we have just raced with a buffer being pinned and it has
* been marked stale, we could end up stalling until someone else
* issues a log force to unpin the stale buffer. Check for the
* race condition here so xfsaild recognizes the buffer is pinned
* and queues a log force to move it along.
*/
if (xfs_buf_ispinned(bp))
return XFS_ITEM_PINNED;
return XFS_ITEM_LOCKED;
}
ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
trace_xfs_buf_item_push(bip);
/* has a previous flush failed due to IO errors? */
if (bp->b_flags & XBF_WRITE_FAIL) {
xfs_buf_alert_ratelimited(bp, "XFS: Failing async write",
"Failing async write on buffer block 0x%llx. Retrying async write.",
(long long)xfs_buf_daddr(bp));
}
if (!xfs_buf_delwri_queue(bp, buffer_list))
rval = XFS_ITEM_FLUSHING;
xfs_buf_unlock(bp);
return rval;
}
/*
* Drop the buffer log item refcount and take appropriate action. This helper
* determines whether the bli must be freed or not, since a decrement to zero
* does not necessarily mean the bli is unused.
*
* Return true if the bli is freed, false otherwise.
*/
bool
xfs_buf_item_put(
struct xfs_buf_log_item *bip)
{
struct xfs_log_item *lip = &bip->bli_item;
bool aborted;
bool dirty;
/* drop the bli ref and return if it wasn't the last one */
if (!atomic_dec_and_test(&bip->bli_refcount))
return false;
/*
* We dropped the last ref and must free the item if clean or aborted.
* If the bli is dirty and non-aborted, the buffer was clean in the
* transaction but still awaiting writeback from previous changes. In
* that case, the bli is freed on buffer writeback completion.
*/
aborted = test_bit(XFS_LI_ABORTED, &lip->li_flags) ||
xlog_is_shutdown(lip->li_log);
dirty = bip->bli_flags & XFS_BLI_DIRTY;
if (dirty && !aborted)
return false;
/*
* The bli is aborted or clean. An aborted item may be in the AIL
* regardless of dirty state. For example, consider an aborted
* transaction that invalidated a dirty bli and cleared the dirty
* state.
*/
if (aborted)
xfs_trans_ail_delete(lip, 0);
xfs_buf_item_relse(bip->bli_buf);
return true;
}
/*
* Release the buffer associated with the buf log item. If there is no dirty
* logged data associated with the buffer recorded in the buf log item, then
* free the buf log item and remove the reference to it in the buffer.
*
* This call ignores the recursion count. It is only called when the buffer
* should REALLY be unlocked, regardless of the recursion count.
*
* We unconditionally drop the transaction's reference to the log item. If the
* item was logged, then another reference was taken when it was pinned, so we
* can safely drop the transaction reference now. This also allows us to avoid
* potential races with the unpin code freeing the bli by not referencing the
* bli after we've dropped the reference count.
*
* If the XFS_BLI_HOLD flag is set in the buf log item, then free the log item
* if necessary but do not unlock the buffer. This is for support of
* xfs_trans_bhold(). Make sure the XFS_BLI_HOLD field is cleared if we don't
* free the item.
*/
STATIC void
xfs_buf_item_release(
struct xfs_log_item *lip)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
struct xfs_buf *bp = bip->bli_buf;
bool released;
bool hold = bip->bli_flags & XFS_BLI_HOLD;
bool stale = bip->bli_flags & XFS_BLI_STALE;
#if defined(DEBUG) || defined(XFS_WARN)
bool ordered = bip->bli_flags & XFS_BLI_ORDERED;
bool dirty = bip->bli_flags & XFS_BLI_DIRTY;
bool aborted = test_bit(XFS_LI_ABORTED,
&lip->li_flags);
#endif
trace_xfs_buf_item_release(bip);
/*
* The bli dirty state should match whether the blf has logged segments
* except for ordered buffers, where only the bli should be dirty.
*/
ASSERT((!ordered && dirty == xfs_buf_item_dirty_format(bip)) ||
(ordered && dirty && !xfs_buf_item_dirty_format(bip)));
ASSERT(!stale || (bip->__bli_format.blf_flags & XFS_BLF_CANCEL));
/*
* Clear the buffer's association with this transaction and
* per-transaction state from the bli, which has been copied above.
*/
bp->b_transp = NULL;
bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD | XFS_BLI_ORDERED);
/*
* Unref the item and unlock the buffer unless held or stale. Stale
* buffers remain locked until final unpin unless the bli is freed by
* the unref call. The latter implies shutdown because buffer
* invalidation dirties the bli and transaction.
*/
released = xfs_buf_item_put(bip);
if (hold || (stale && !released))
return;
ASSERT(!stale || aborted);
xfs_buf_relse(bp);
}
STATIC void
xfs_buf_item_committing(
struct xfs_log_item *lip,
xfs_csn_t seq)
{
return xfs_buf_item_release(lip);
}
/*
* This is called to find out where the oldest active copy of the
* buf log item in the on disk log resides now that the last log
* write of it completed at the given lsn.
* We always re-log all the dirty data in a buffer, so usually the
* latest copy in the on disk log is the only one that matters. For
* those cases we simply return the given lsn.
*
* The one exception to this is for buffers full of newly allocated
* inodes. These buffers are only relogged with the XFS_BLI_INODE_BUF
* flag set, indicating that only the di_next_unlinked fields from the
* inodes in the buffers will be replayed during recovery. If the
* original newly allocated inode images have not yet been flushed
* when the buffer is so relogged, then we need to make sure that we
* keep the old images in the 'active' portion of the log. We do this
* by returning the original lsn of that transaction here rather than
* the current one.
*/
STATIC xfs_lsn_t
xfs_buf_item_committed(
struct xfs_log_item *lip,
xfs_lsn_t lsn)
{
struct xfs_buf_log_item *bip = BUF_ITEM(lip);
trace_xfs_buf_item_committed(bip);
if ((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) && lip->li_lsn != 0)
return lip->li_lsn;
return lsn;
}
static const struct xfs_item_ops xfs_buf_item_ops = {
.iop_size = xfs_buf_item_size,
.iop_format = xfs_buf_item_format,
.iop_pin = xfs_buf_item_pin,
.iop_unpin = xfs_buf_item_unpin,
.iop_release = xfs_buf_item_release,
.iop_committing = xfs_buf_item_committing,
.iop_committed = xfs_buf_item_committed,
.iop_push = xfs_buf_item_push,
};
STATIC void
xfs_buf_item_get_format(
struct xfs_buf_log_item *bip,
int count)
{
ASSERT(bip->bli_formats == NULL);
bip->bli_format_count = count;
if (count == 1) {
bip->bli_formats = &bip->__bli_format;
return;
}
bip->bli_formats = kmem_zalloc(count * sizeof(struct xfs_buf_log_format),
0);
}
STATIC void
xfs_buf_item_free_format(
struct xfs_buf_log_item *bip)
{
if (bip->bli_formats != &bip->__bli_format) {
kmem_free(bip->bli_formats);
bip->bli_formats = NULL;
}
}
/*
* Allocate a new buf log item to go with the given buffer.
* Set the buffer's b_log_item field to point to the new
* buf log item.
*/
int
xfs_buf_item_init(
struct xfs_buf *bp,
struct xfs_mount *mp)
{
struct xfs_buf_log_item *bip = bp->b_log_item;
int chunks;
int map_size;
int i;
/*
* Check to see if there is already a buf log item for
* this buffer. If we do already have one, there is
* nothing to do here so return.
*/
ASSERT(bp->b_mount == mp);
if (bip) {
ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
ASSERT(!bp->b_transp);
ASSERT(bip->bli_buf == bp);
return 0;
}
bip = kmem_cache_zalloc(xfs_buf_item_cache, GFP_KERNEL | __GFP_NOFAIL);
xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
bip->bli_buf = bp;
/*
* chunks is the number of XFS_BLF_CHUNK size pieces the buffer
* can be divided into. Make sure not to truncate any pieces.
* map_size is the size of the bitmap needed to describe the
* chunks of the buffer.
*
* Discontiguous buffer support follows the layout of the underlying
* buffer. This makes the implementation as simple as possible.
*/
xfs_buf_item_get_format(bip, bp->b_map_count);
for (i = 0; i < bip->bli_format_count; i++) {
chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
XFS_BLF_CHUNK);
map_size = DIV_ROUND_UP(chunks, NBWORD);
if (map_size > XFS_BLF_DATAMAP_SIZE) {
kmem_cache_free(xfs_buf_item_cache, bip);
xfs_err(mp,
"buffer item dirty bitmap (%u uints) too small to reflect %u bytes!",
map_size,
BBTOB(bp->b_maps[i].bm_len));
return -EFSCORRUPTED;
}
bip->bli_formats[i].blf_type = XFS_LI_BUF;
bip->bli_formats[i].blf_blkno = bp->b_maps[i].bm_bn;
bip->bli_formats[i].blf_len = bp->b_maps[i].bm_len;
bip->bli_formats[i].blf_map_size = map_size;
}
bp->b_log_item = bip;
xfs_buf_hold(bp);
return 0;
}
/*
* Mark bytes first through last inclusive as dirty in the buf
* item's bitmap.
*/
static void
xfs_buf_item_log_segment(
uint first,
uint last,
uint *map)
{
uint first_bit;
uint last_bit;
uint bits_to_set;
uint bits_set;
uint word_num;
uint *wordp;
uint bit;
uint end_bit;
uint mask;
ASSERT(first < XFS_BLF_DATAMAP_SIZE * XFS_BLF_CHUNK * NBWORD);
ASSERT(last < XFS_BLF_DATAMAP_SIZE * XFS_BLF_CHUNK * NBWORD);
/*
* Convert byte offsets to bit numbers.
*/
first_bit = first >> XFS_BLF_SHIFT;
last_bit = last >> XFS_BLF_SHIFT;
/*
* Calculate the total number of bits to be set.
*/
bits_to_set = last_bit - first_bit + 1;
/*
* Get a pointer to the first word in the bitmap
* to set a bit in.
*/
word_num = first_bit >> BIT_TO_WORD_SHIFT;
wordp = &map[word_num];
/*
* Calculate the starting bit in the first word.
*/
bit = first_bit & (uint)(NBWORD - 1);
/*
* First set any bits in the first word of our range.
* If it starts at bit 0 of the word, it will be
* set below rather than here. That is what the variable
* bit tells us. The variable bits_set tracks the number
* of bits that have been set so far. End_bit is the number
* of the last bit to be set in this word plus one.
*/
if (bit) {
end_bit = min(bit + bits_to_set, (uint)NBWORD);
mask = ((1U << (end_bit - bit)) - 1) << bit;
*wordp |= mask;
wordp++;
bits_set = end_bit - bit;
} else {
bits_set = 0;
}
/*
* Now set bits a whole word at a time that are between
* first_bit and last_bit.
*/
while ((bits_to_set - bits_set) >= NBWORD) {
*wordp = 0xffffffff;
bits_set += NBWORD;
wordp++;
}
/*
* Finally, set any bits left to be set in one last partial word.
*/
end_bit = bits_to_set - bits_set;
if (end_bit) {
mask = (1U << end_bit) - 1;
*wordp |= mask;
}
}
/*
* Mark bytes first through last inclusive as dirty in the buf
* item's bitmap.
*/
void
xfs_buf_item_log(
struct xfs_buf_log_item *bip,
uint first,
uint last)
{
int i;
uint start;
uint end;
struct xfs_buf *bp = bip->bli_buf;
/*
* walk each buffer segment and mark them dirty appropriately.
*/
start = 0;
for (i = 0; i < bip->bli_format_count; i++) {
if (start > last)
break;
end = start + BBTOB(bp->b_maps[i].bm_len) - 1;
/* skip to the map that includes the first byte to log */
if (first > end) {
start += BBTOB(bp->b_maps[i].bm_len);
continue;
}
/*
* Trim the range to this segment and mark it in the bitmap.
* Note that we must convert buffer offsets to segment relative
* offsets (e.g., the first byte of each segment is byte 0 of
* that segment).
*/
if (first < start)
first = start;
if (end > last)
end = last;
xfs_buf_item_log_segment(first - start, end - start,
&bip->bli_formats[i].blf_data_map[0]);
start += BBTOB(bp->b_maps[i].bm_len);
}
}
/*
* Return true if the buffer has any ranges logged/dirtied by a transaction,
* false otherwise.
*/
bool
xfs_buf_item_dirty_format(
struct xfs_buf_log_item *bip)
{
int i;
for (i = 0; i < bip->bli_format_count; i++) {
if (!xfs_bitmap_empty(bip->bli_formats[i].blf_data_map,
bip->bli_formats[i].blf_map_size))
return true;
}
return false;
}
STATIC void
xfs_buf_item_free(
struct xfs_buf_log_item *bip)
{
xfs_buf_item_free_format(bip);
kmem_free(bip->bli_item.li_lv_shadow);
kmem_cache_free(xfs_buf_item_cache, bip);
}
/*
* xfs_buf_item_relse() is called when the buf log item is no longer needed.
*/
void
xfs_buf_item_relse(
struct xfs_buf *bp)
{
struct xfs_buf_log_item *bip = bp->b_log_item;
trace_xfs_buf_item_relse(bp, _RET_IP_);
ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags));
if (atomic_read(&bip->bli_refcount))
return;
bp->b_log_item = NULL;
xfs_buf_rele(bp);
xfs_buf_item_free(bip);
}
void
xfs_buf_item_done(
struct xfs_buf *bp)
{
/*
* If we are forcibly shutting down, this may well be off the AIL
* already. That's because we simulate the log-committed callbacks to
* unpin these buffers. Or we may never have put this item on AIL
* because of the transaction was aborted forcibly.
* xfs_trans_ail_delete() takes care of these.
*
* Either way, AIL is useless if we're forcing a shutdown.
*
* Note that log recovery writes might have buffer items that are not on
* the AIL even when the file system is not shut down.
*/
xfs_trans_ail_delete(&bp->b_log_item->bli_item,
(bp->b_flags & _XBF_LOGRECOVERY) ? 0 :
SHUTDOWN_CORRUPT_INCORE);
xfs_buf_item_relse(bp);
}
| linux-master | fs/xfs/xfs_buf_item.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010 Red Hat, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_alloc.h"
#include "xfs_discard.h"
#include "xfs_error.h"
#include "xfs_extent_busy.h"
#include "xfs_trace.h"
#include "xfs_log.h"
#include "xfs_ag.h"
STATIC int
xfs_trim_extents(
struct xfs_perag *pag,
xfs_daddr_t start,
xfs_daddr_t end,
xfs_daddr_t minlen,
uint64_t *blocks_trimmed)
{
struct xfs_mount *mp = pag->pag_mount;
struct block_device *bdev = mp->m_ddev_targp->bt_bdev;
struct xfs_btree_cur *cur;
struct xfs_buf *agbp;
struct xfs_agf *agf;
int error;
int i;
/*
* Force out the log. This means any transactions that might have freed
* space before we take the AGF buffer lock are now on disk, and the
* volatile disk cache is flushed.
*/
xfs_log_force(mp, XFS_LOG_SYNC);
error = xfs_alloc_read_agf(pag, NULL, 0, &agbp);
if (error)
return error;
agf = agbp->b_addr;
cur = xfs_allocbt_init_cursor(mp, NULL, agbp, pag, XFS_BTNUM_CNT);
/*
* Look up the longest btree in the AGF and start with it.
*/
error = xfs_alloc_lookup_ge(cur, 0, be32_to_cpu(agf->agf_longest), &i);
if (error)
goto out_del_cursor;
/*
* Loop until we are done with all extents that are large
* enough to be worth discarding.
*/
while (i) {
xfs_agblock_t fbno;
xfs_extlen_t flen;
xfs_daddr_t dbno;
xfs_extlen_t dlen;
error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
if (error)
break;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
break;
}
ASSERT(flen <= be32_to_cpu(agf->agf_longest));
/*
* use daddr format for all range/len calculations as that is
* the format the range/len variables are supplied in by
* userspace.
*/
dbno = XFS_AGB_TO_DADDR(mp, pag->pag_agno, fbno);
dlen = XFS_FSB_TO_BB(mp, flen);
/*
* Too small? Give up.
*/
if (dlen < minlen) {
trace_xfs_discard_toosmall(mp, pag->pag_agno, fbno, flen);
break;
}
/*
* If the extent is entirely outside of the range we are
* supposed to discard skip it. Do not bother to trim
* down partially overlapping ranges for now.
*/
if (dbno + dlen < start || dbno > end) {
trace_xfs_discard_exclude(mp, pag->pag_agno, fbno, flen);
goto next_extent;
}
/*
* If any blocks in the range are still busy, skip the
* discard and try again the next time.
*/
if (xfs_extent_busy_search(mp, pag, fbno, flen)) {
trace_xfs_discard_busy(mp, pag->pag_agno, fbno, flen);
goto next_extent;
}
trace_xfs_discard_extent(mp, pag->pag_agno, fbno, flen);
error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS);
if (error)
break;
*blocks_trimmed += flen;
next_extent:
error = xfs_btree_decrement(cur, 0, &i);
if (error)
break;
if (fatal_signal_pending(current)) {
error = -ERESTARTSYS;
break;
}
}
out_del_cursor:
xfs_btree_del_cursor(cur, error);
xfs_buf_relse(agbp);
return error;
}
/*
* trim a range of the filesystem.
*
* Note: the parameters passed from userspace are byte ranges into the
* filesystem which does not match to the format we use for filesystem block
* addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
* is a linear address range. Hence we need to use DADDR based conversions and
* comparisons for determining the correct offset and regions to trim.
*/
int
xfs_ioc_trim(
struct xfs_mount *mp,
struct fstrim_range __user *urange)
{
struct xfs_perag *pag;
unsigned int granularity =
bdev_discard_granularity(mp->m_ddev_targp->bt_bdev);
struct fstrim_range range;
xfs_daddr_t start, end, minlen;
xfs_agnumber_t agno;
uint64_t blocks_trimmed = 0;
int error, last_error = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!bdev_max_discard_sectors(mp->m_ddev_targp->bt_bdev))
return -EOPNOTSUPP;
/*
* We haven't recovered the log, so we cannot use our bnobt-guided
* storage zapping commands.
*/
if (xfs_has_norecovery(mp))
return -EROFS;
if (copy_from_user(&range, urange, sizeof(range)))
return -EFAULT;
range.minlen = max_t(u64, granularity, range.minlen);
minlen = BTOBB(range.minlen);
/*
* Truncating down the len isn't actually quite correct, but using
* BBTOB would mean we trivially get overflows for values
* of ULLONG_MAX or slightly lower. And ULLONG_MAX is the default
* used by the fstrim application. In the end it really doesn't
* matter as trimming blocks is an advisory interface.
*/
if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
range.len < mp->m_sb.sb_blocksize)
return -EINVAL;
start = BTOBB(range.start);
end = start + BTOBBT(range.len) - 1;
if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1;
agno = xfs_daddr_to_agno(mp, start);
for_each_perag_range(mp, agno, xfs_daddr_to_agno(mp, end), pag) {
error = xfs_trim_extents(pag, start, end, minlen,
&blocks_trimmed);
if (error) {
last_error = error;
if (error == -ERESTARTSYS) {
xfs_perag_rele(pag);
break;
}
}
}
if (last_error)
return last_error;
range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
if (copy_to_user(urange, &range, sizeof(range)))
return -EFAULT;
return 0;
}
| linux-master | fs/xfs/xfs_discard.c |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.