text: /*
   * Copyright (C) 2007 Oracle.  All rights reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public
   * License v2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public
   * License along with this program; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   * Boston, MA 021110-1307, USA.
   */
  
  #include <linux/kernel.h>
  #include <linux/bio.h>
  #include <linux/buffer_head.h>
  #include <linux/file.h>
  #include <linux/fs.h>
  #include <linux/fsnotify.h>
  #include <linux/pagemap.h>
  #include <linux/highmem.h>
  #include <linux/time.h>
  #include <linux/init.h>
  #include <linux/string.h>
  #include <linux/backing-dev.h>
  #include <linux/mount.h>
  #include <linux/mpage.h>
  #include <linux/namei.h>
  #include <linux/swap.h>
  #include <linux/writeback.h>
  #include <linux/statfs.h>
  #include <linux/compat.h>
  #include <linux/bit_spinlock.h>
  #include <linux/security.h>
  #include <linux/xattr.h>
  #include <linux/vmalloc.h>
  #include "compat.h"
  #include "ctree.h"
  #include "disk-io.h"
  #include "transaction.h"
  #include "btrfs_inode.h"
  #include "ioctl.h"
  #include "print-tree.h"
  #include "volumes.h"
  #include "locking.h"
  
  /* Mask out flags that are inappropriate for the given type of inode. */
  static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
  {
  	if (S_ISDIR(mode))
  		return flags;
  	else if (S_ISREG(mode))
  		return flags & ~FS_DIRSYNC_FL;
  	else
  		return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
  }
  
  /*
   * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
   */
  static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
  {
  	unsigned int iflags = 0;
  
  	if (flags & BTRFS_INODE_SYNC)
  		iflags |= FS_SYNC_FL;
  	if (flags & BTRFS_INODE_IMMUTABLE)
  		iflags |= FS_IMMUTABLE_FL;
  	if (flags & BTRFS_INODE_APPEND)
  		iflags |= FS_APPEND_FL;
  	if (flags & BTRFS_INODE_NODUMP)
  		iflags |= FS_NODUMP_FL;
  	if (flags & BTRFS_INODE_NOATIME)
  		iflags |= FS_NOATIME_FL;
  	if (flags & BTRFS_INODE_DIRSYNC)
  		iflags |= FS_DIRSYNC_FL;
  
  	return iflags;
  }
  
  /*
   * Update inode->i_flags based on the btrfs internal flags.
   */
  void btrfs_update_iflags(struct inode *inode)
  {
  	struct btrfs_inode *ip = BTRFS_I(inode);
  
  	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
  
  	if (ip->flags & BTRFS_INODE_SYNC)
  		inode->i_flags |= S_SYNC;
  	if (ip->flags & BTRFS_INODE_IMMUTABLE)
  		inode->i_flags |= S_IMMUTABLE;
  	if (ip->flags & BTRFS_INODE_APPEND)
  		inode->i_flags |= S_APPEND;
  	if (ip->flags & BTRFS_INODE_NOATIME)
  		inode->i_flags |= S_NOATIME;
  	if (ip->flags & BTRFS_INODE_DIRSYNC)
  		inode->i_flags |= S_DIRSYNC;
  }
  
  /*
   * Inherit flags from the parent inode.
   *
   * Unlike extN we don't have any flags we don't want to inherit currently.
   */
  void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
  {
  	unsigned int flags;
  
  	if (!dir)
  		return;
  
  	flags = BTRFS_I(dir)->flags;
  
  	if (S_ISREG(inode->i_mode))
  		flags &= ~BTRFS_INODE_DIRSYNC;
  	else if (!S_ISDIR(inode->i_mode))
  		flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);
  
  	BTRFS_I(inode)->flags = flags;
  	btrfs_update_iflags(inode);
  }
  
  static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
  {
  	struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
  	unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
  
  	if (copy_to_user(arg, &flags, sizeof(flags)))
  		return -EFAULT;
  	return 0;
  }
  
  static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
  {
  	struct inode *inode = file->f_path.dentry->d_inode;
  	struct btrfs_inode *ip = BTRFS_I(inode);
  	struct btrfs_root *root = ip->root;
  	struct btrfs_trans_handle *trans;
  	unsigned int flags, oldflags;
  	int ret;
  
  	if (copy_from_user(&flags, arg, sizeof(flags)))
  		return -EFAULT;
  
  	if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
  		      FS_NOATIME_FL | FS_NODUMP_FL | \
  		      FS_SYNC_FL | FS_DIRSYNC_FL))
  		return -EOPNOTSUPP;
  
  	if (!is_owner_or_cap(inode))
  		return -EACCES;
  
  	mutex_lock(&inode->i_mutex);
  
  	flags = btrfs_mask_flags(inode->i_mode, flags);
  	oldflags = btrfs_flags_to_ioctl(ip->flags);
  	if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
  		if (!capable(CAP_LINUX_IMMUTABLE)) {
  			ret = -EPERM;
  			goto out_unlock;
  		}
  	}
  
  	ret = mnt_want_write(file->f_path.mnt);
  	if (ret)
  		goto out_unlock;
  
  	if (flags & FS_SYNC_FL)
  		ip->flags |= BTRFS_INODE_SYNC;
  	else
  		ip->flags &= ~BTRFS_INODE_SYNC;
  	if (flags & FS_IMMUTABLE_FL)
  		ip->flags |= BTRFS_INODE_IMMUTABLE;
  	else
  		ip->flags &= ~BTRFS_INODE_IMMUTABLE;
  	if (flags & FS_APPEND_FL)
  		ip->flags |= BTRFS_INODE_APPEND;
  	else
  		ip->flags &= ~BTRFS_INODE_APPEND;
  	if (flags & FS_NODUMP_FL)
  		ip->flags |= BTRFS_INODE_NODUMP;
  	else
  		ip->flags &= ~BTRFS_INODE_NODUMP;
  	if (flags & FS_NOATIME_FL)
  		ip->flags |= BTRFS_INODE_NOATIME;
  	else
  		ip->flags &= ~BTRFS_INODE_NOATIME;
  	if (flags & FS_DIRSYNC_FL)
  		ip->flags |= BTRFS_INODE_DIRSYNC;
  	else
  		ip->flags &= ~BTRFS_INODE_DIRSYNC;
  
  
  	trans = btrfs_join_transaction(root, 1);
  	BUG_ON(!trans);
  
  	ret = btrfs_update_inode(trans, root, inode);
  	BUG_ON(ret);
  
  	btrfs_update_iflags(inode);
  	inode->i_ctime = CURRENT_TIME;
  	btrfs_end_transaction(trans, root);
  
  	mnt_drop_write(file->f_path.mnt);
   out_unlock:
  	mutex_unlock(&inode->i_mutex);
  	return 0;
  }
  
  static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
  {
  	struct inode *inode = file->f_path.dentry->d_inode;
  
  	return put_user(inode->i_generation, arg);
  }
  
  static noinline int create_subvol(struct btrfs_root *root,
  				  struct dentry *dentry,
  				  char *name, int namelen)
  {
  	struct btrfs_trans_handle *trans;
  	struct btrfs_key key;
  	struct btrfs_root_item root_item;
  	struct btrfs_inode_item *inode_item;
  	struct extent_buffer *leaf;
  	struct btrfs_root *new_root;
  	struct inode *dir = dentry->d_parent->d_inode;
  	int ret;
  	int err;
  	u64 objectid;
  	u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
  	u64 index = 0;
  	unsigned long nr = 1;
  
  	/*
  	 * 1 - inode item
  	 * 2 - refs
  	 * 1 - root item
  	 * 2 - dir items
  	 */
  	ret = btrfs_reserve_metadata_space(root, 6);
  	if (ret)
  		return ret;
  
  	trans = btrfs_start_transaction(root, 1);
  	BUG_ON(!trans);
  
  	ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
  				       0, &objectid);
  	if (ret)
  		goto fail;
  
  	leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
  				      0, objectid, NULL, 0, 0, 0);
  	if (IS_ERR(leaf)) {
  		ret = PTR_ERR(leaf);
  		goto fail;
  	}
  
  	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
  	btrfs_set_header_bytenr(leaf, leaf->start);
  	btrfs_set_header_generation(leaf, trans->transid);
  	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
  	btrfs_set_header_owner(leaf, objectid);
  
  	write_extent_buffer(leaf, root->fs_info->fsid,
  			    (unsigned long)btrfs_header_fsid(leaf),
  			    BTRFS_FSID_SIZE);
  	write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
  			    (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
  			    BTRFS_UUID_SIZE);
  	btrfs_mark_buffer_dirty(leaf);
  
  	inode_item = &root_item.inode;
  	memset(inode_item, 0, sizeof(*inode_item));
  	inode_item->generation = cpu_to_le64(1);
  	inode_item->size = cpu_to_le64(3);
  	inode_item->nlink = cpu_to_le32(1);
  	inode_item->nbytes = cpu_to_le64(root->leafsize);
  	inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
  
  	btrfs_set_root_bytenr(&root_item, leaf->start);
  	btrfs_set_root_generation(&root_item, trans->transid);
  	btrfs_set_root_level(&root_item, 0);
  	btrfs_set_root_refs(&root_item, 1);
  	btrfs_set_root_used(&root_item, 0);
  	btrfs_set_root_last_snapshot(&root_item, 0);
  
  	memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
  	root_item.drop_level = 0;
  
  	btrfs_tree_unlock(leaf);
  	free_extent_buffer(leaf);
  	leaf = NULL;
  
  	btrfs_set_root_dirid(&root_item, new_dirid);
  
  	key.objectid = objectid;
  	key.offset = 0;
  	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
  	ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
  				&root_item);
  	if (ret)
  		goto fail;
  
  	key.offset = (u64)-1;
  	new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
  	BUG_ON(IS_ERR(new_root));
  
  	btrfs_record_root_in_trans(trans, new_root);
  
  	ret = btrfs_create_subvol_root(trans, new_root, new_dirid,
  				       BTRFS_I(dir)->block_group);
  	/*
  	 * insert the directory item
  	 */
  	ret = btrfs_set_inode_index(dir, &index);
  	BUG_ON(ret);
  
  	ret = btrfs_insert_dir_item(trans, root,
  				    name, namelen, dir->i_ino, &key,
  				    BTRFS_FT_DIR, index);
  	if (ret)
  		goto fail;
  
  	btrfs_i_size_write(dir, dir->i_size + namelen * 2);
  	ret = btrfs_update_inode(trans, root, dir);
  	BUG_ON(ret);
  
  	ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
  				 objectid, root->root_key.objectid,
  				 dir->i_ino, index, name, namelen);
  
  	BUG_ON(ret);
  
  	d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
  fail:
  	nr = trans->blocks_used;
  	err = btrfs_commit_transaction(trans, root);
  	if (err && !ret)
  		ret = err;
  
  	btrfs_unreserve_metadata_space(root, 6);
  	btrfs_btree_balance_dirty(root, nr);
  	return ret;
  }
  
  static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
  			   char *name, int namelen)
  {
  	struct btrfs_pending_snapshot *pending_snapshot;
  	struct btrfs_trans_handle *trans;
  	int ret = 0;
  	int err;
  	unsigned long nr = 0;
  
  	if (!root->ref_cows)
  		return -EINVAL;
  
  	/*
  	 * 1 - inode item
  	 * 2 - refs
  	 * 1 - root item
  	 * 2 - dir items
  	 */
  	ret = btrfs_reserve_metadata_space(root, 6);
  	if (ret)
  		goto fail_unlock;
  
  	pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
  	if (!pending_snapshot) {
  		ret = -ENOMEM;
  		btrfs_unreserve_metadata_space(root, 6);
  		goto fail_unlock;
  	}
  	pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
  	if (!pending_snapshot->name) {
  		ret = -ENOMEM;
  		kfree(pending_snapshot);
  		btrfs_unreserve_metadata_space(root, 6);
  		goto fail_unlock;
  	}
  	memcpy(pending_snapshot->name, name, namelen);
  	pending_snapshot->name[namelen] = '\0';
  	pending_snapshot->dentry = dentry;
  	trans = btrfs_start_transaction(root, 1);
  	BUG_ON(!trans);
  	pending_snapshot->root = root;
  	list_add(&pending_snapshot->list,
  		 &trans->transaction->pending_snapshots);
  	err = btrfs_commit_transaction(trans, root);
  
  fail_unlock:
  	btrfs_btree_balance_dirty(root, nr);
  	return ret;
  }
  
  /* copy of may_create in fs/namei.c() */
  static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
  {
  	if (child->d_inode)
  		return -EEXIST;
  	if (IS_DEADDIR(dir))
  		return -ENOENT;
  	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
  }
  
  /*
   * Create a new subvolume below @parent.  This is largely modeled after
   * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
   * inside this filesystem so it's quite a bit simpler.
   */
  static noinline int btrfs_mksubvol(struct path *parent,
  				   char *name, int namelen,
  				   struct btrfs_root *snap_src)
  {
  	struct inode *dir  = parent->dentry->d_inode;
  	struct dentry *dentry;
  	int error;
  
  	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
  
  	dentry = lookup_one_len(name, parent->dentry, namelen);
  	error = PTR_ERR(dentry);
  	if (IS_ERR(dentry))
  		goto out_unlock;
  
  	error = -EEXIST;
  	if (dentry->d_inode)
  		goto out_dput;
  
  	error = mnt_want_write(parent->mnt);
  	if (error)
  		goto out_dput;
  
  	error = btrfs_may_create(dir, dentry);
  	if (error)
  		goto out_drop_write;
  
  	down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
  
  	if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
  		goto out_up_read;
  
  	if (snap_src) {
  		error = create_snapshot(snap_src, dentry,
  					name, namelen);
  	} else {
  		error = create_subvol(BTRFS_I(dir)->root, dentry,
  				      name, namelen);
  	}
  	if (!error)
  		fsnotify_mkdir(dir, dentry);
  out_up_read:
  	up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
  out_drop_write:
  	mnt_drop_write(parent->mnt);
  out_dput:
  	dput(dentry);
  out_unlock:
  	mutex_unlock(&dir->i_mutex);
  	return error;
  }
  
  static int btrfs_defrag_file(struct file *file)
  {
  	struct inode *inode = fdentry(file)->d_inode;
  	struct btrfs_root *root = BTRFS_I(inode)->root;
  	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
  	struct btrfs_ordered_extent *ordered;
  	struct page *page;
  	unsigned long last_index;
  	unsigned long ra_pages = root->fs_info->bdi.ra_pages;
  	unsigned long total_read = 0;
  	u64 page_start;
  	u64 page_end;
  	unsigned long i;
  	int ret;
  
  	ret = btrfs_check_data_free_space(root, inode, inode->i_size);
  	if (ret)
  		return -ENOSPC;
  
  	mutex_lock(&inode->i_mutex);
  	last_index = inode->i_size >> PAGE_CACHE_SHIFT;
  	for (i = 0; i <= last_index; i++) {
  		if (total_read % ra_pages == 0) {
  			btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
  				       min(last_index, i + ra_pages - 1));
  		}
  		total_read++;
  again:
  		page = grab_cache_page(inode->i_mapping, i);
  		if (!page)
  			goto out_unlock;
  		if (!PageUptodate(page)) {
  			btrfs_readpage(NULL, page);
  			lock_page(page);
  			if (!PageUptodate(page)) {
  				unlock_page(page);
  				page_cache_release(page);
  				goto out_unlock;
  			}
  		}
  
  		wait_on_page_writeback(page);
  
  		page_start = (u64)page->index << PAGE_CACHE_SHIFT;
  		page_end = page_start + PAGE_CACHE_SIZE - 1;
  		lock_extent(io_tree, page_start, page_end, GFP_NOFS);
  
  		ordered = btrfs_lookup_ordered_extent(inode, page_start);
  		if (ordered) {
  			unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
  			unlock_page(page);
  			page_cache_release(page);
  			btrfs_start_ordered_extent(inode, ordered, 1);
  			btrfs_put_ordered_extent(ordered);
  			goto again;
  		}
  		set_page_extent_mapped(page);
  
  		/*
  		 * this makes sure page_mkwrite is called on the
  		 * page if it is dirtied again later
  		 */
  		clear_page_dirty_for_io(page);
  
  		btrfs_set_extent_delalloc(inode, page_start, page_end);
  		set_page_dirty(page);
  		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
  		unlock_page(page);
  		page_cache_release(page);
  		balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
  	}
  
  out_unlock:
  	mutex_unlock(&inode->i_mutex);
  	return 0;
  }
  
  static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
  					void __user *arg)
  {
  	u64 new_size;
  	u64 old_size;
  	u64 devid = 1;
  	struct btrfs_ioctl_vol_args *vol_args;
  	struct btrfs_trans_handle *trans;
  	struct btrfs_device *device = NULL;
  	char *sizestr;
  	char *devstr = NULL;
  	int ret = 0;
  	int namelen;
  	int mod = 0;
  
  	if (root->fs_info->sb->s_flags & MS_RDONLY)
  		return -EROFS;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	vol_args = memdup_user(arg, sizeof(*vol_args));
  	if (IS_ERR(vol_args))
  		return PTR_ERR(vol_args);
  
  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
  	namelen = strlen(vol_args->name);
  
  	mutex_lock(&root->fs_info->volume_mutex);
  	sizestr = vol_args->name;
  	devstr = strchr(sizestr, ':');
  	if (devstr) {
  		char *end;
  		sizestr = devstr + 1;
  		*devstr = '\0';
  		devstr = vol_args->name;
  		devid = simple_strtoull(devstr, &end, 10);
  		printk(KERN_INFO "resizing devid %llu\n",
  		       (unsigned long long)devid);
  	}
  	device = btrfs_find_device(root, devid, NULL, NULL);
  	if (!device) {
  		printk(KERN_INFO "resizer unable to find device %llu\n",
  		       (unsigned long long)devid);
  		ret = -EINVAL;
  		goto out_unlock;
  	}
  	if (!strcmp(sizestr, "max"))
  		new_size = device->bdev->bd_inode->i_size;
  	else {
  		if (sizestr[0] == '-') {
  			mod = -1;
  			sizestr++;
  		} else if (sizestr[0] == '+') {
  			mod = 1;
  			sizestr++;
  		}
  		new_size = btrfs_parse_size(sizestr);
  		if (new_size == 0) {
  			ret = -EINVAL;
  			goto out_unlock;
  		}
  	}
  
  	old_size = device->total_bytes;
  
  	if (mod < 0) {
  		if (new_size > old_size) {
  			ret = -EINVAL;
  			goto out_unlock;
  		}
  		new_size = old_size - new_size;
  	} else if (mod > 0) {
  		new_size = old_size + new_size;
  	}
  
  	if (new_size < 256 * 1024 * 1024) {
  		ret = -EINVAL;
  		goto out_unlock;
  	}
  	if (new_size > device->bdev->bd_inode->i_size) {
  		ret = -EFBIG;
  		goto out_unlock;
  	}
  
  	do_div(new_size, root->sectorsize);
  	new_size *= root->sectorsize;
  
  	printk(KERN_INFO "new size for %s is %llu\n",
  		device->name, (unsigned long long)new_size);
  
  	if (new_size > old_size) {
  		trans = btrfs_start_transaction(root, 1);
  		ret = btrfs_grow_device(trans, device, new_size);
  		btrfs_commit_transaction(trans, root);
  	} else {
  		ret = btrfs_shrink_device(device, new_size);
  	}
  
  out_unlock:
  	mutex_unlock(&root->fs_info->volume_mutex);
  	kfree(vol_args);
  	return ret;
  }
  
  static noinline int btrfs_ioctl_snap_create(struct file *file,
  					    void __user *arg, int subvol)
  {
  	struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
  	struct btrfs_ioctl_vol_args *vol_args;
  	struct file *src_file;
  	int namelen;
  	int ret = 0;
  
  	if (root->fs_info->sb->s_flags & MS_RDONLY)
  		return -EROFS;
  
  	vol_args = memdup_user(arg, sizeof(*vol_args));
  	if (IS_ERR(vol_args))
  		return PTR_ERR(vol_args);
  
  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
  	namelen = strlen(vol_args->name);
  	if (strchr(vol_args->name, '/')) {
  		ret = -EINVAL;
  		goto out;
  	}
  
  	if (subvol) {
  		ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
  				     NULL);
  	} else {
  		struct inode *src_inode;
  		src_file = fget(vol_args->fd);
  		if (!src_file) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		src_inode = src_file->f_path.dentry->d_inode;
  		if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
  			printk(KERN_INFO "btrfs: Snapshot src from "
  			       "another FS\n");
  			ret = -EINVAL;
  			fput(src_file);
  			goto out;
  		}
  		ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
  				     BTRFS_I(src_inode)->root);
  		fput(src_file);
  	}
  out:
  	kfree(vol_args);
  	return ret;
  }
  
  /*
   * helper to check if the subvolume references other subvolumes
   */
  static noinline int may_destroy_subvol(struct btrfs_root *root)
  {
  	struct btrfs_path *path;
  	struct btrfs_key key;
  	int ret;
  
  	path = btrfs_alloc_path();
  	if (!path)
  		return -ENOMEM;
  
  	key.objectid = root->root_key.objectid;
  	key.type = BTRFS_ROOT_REF_KEY;
  	key.offset = (u64)-1;
  
  	ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
  				&key, path, 0, 0);
  	if (ret < 0)
  		goto out;
  	BUG_ON(ret == 0);
  
  	ret = 0;
  	if (path->slots[0] > 0) {
  		path->slots[0]--;
  		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
  		if (key.objectid == root->root_key.objectid &&
  		    key.type == BTRFS_ROOT_REF_KEY)
  			ret = -ENOTEMPTY;
  	}
  out:
  	btrfs_free_path(path);
  	return ret;
  }
  
  static noinline int btrfs_ioctl_snap_destroy(struct file *file,
  					     void __user *arg)
  {
  	struct dentry *parent = fdentry(file);
  	struct dentry *dentry;
  	struct inode *dir = parent->d_inode;
  	struct inode *inode;
  	struct btrfs_root *root = BTRFS_I(dir)->root;
  	struct btrfs_root *dest = NULL;
  	struct btrfs_ioctl_vol_args *vol_args;
  	struct btrfs_trans_handle *trans;
  	int namelen;
  	int ret;
  	int err = 0;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	vol_args = memdup_user(arg, sizeof(*vol_args));
  	if (IS_ERR(vol_args))
  		return PTR_ERR(vol_args);
  
  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
  	namelen = strlen(vol_args->name);
  	if (strchr(vol_args->name, '/') ||
  	    strncmp(vol_args->name, "..", namelen) == 0) {
  		err = -EINVAL;
  		goto out;
  	}
  
  	err = mnt_want_write(file->f_path.mnt);
  	if (err)
  		goto out;
  
  	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
  	dentry = lookup_one_len(vol_args->name, parent, namelen);
  	if (IS_ERR(dentry)) {
  		err = PTR_ERR(dentry);
  		goto out_unlock_dir;
  	}
  
  	if (!dentry->d_inode) {
  		err = -ENOENT;
  		goto out_dput;
  	}
  
  	inode = dentry->d_inode;
  	if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
  		err = -EINVAL;
  		goto out_dput;
  	}
  
  	dest = BTRFS_I(inode)->root;
  
  	mutex_lock(&inode->i_mutex);
  	err = d_invalidate(dentry);
  	if (err)
  		goto out_unlock;
  
  	down_write(&root->fs_info->subvol_sem);
  
  	err = may_destroy_subvol(dest);
  	if (err)
  		goto out_up_write;
  
  	trans = btrfs_start_transaction(root, 1);
  	ret = btrfs_unlink_subvol(trans, root, dir,
  				dest->root_key.objectid,
  				dentry->d_name.name,
  				dentry->d_name.len);
  	BUG_ON(ret);
  
  	btrfs_record_root_in_trans(trans, dest);
  
  	memset(&dest->root_item.drop_progress, 0,
  		sizeof(dest->root_item.drop_progress));
  	dest->root_item.drop_level = 0;
  	btrfs_set_root_refs(&dest->root_item, 0);
  
  	ret = btrfs_insert_orphan_item(trans,
  				root->fs_info->tree_root,
  				dest->root_key.objectid);
  	BUG_ON(ret);
  
  	ret = btrfs_commit_transaction(trans, root);
  	BUG_ON(ret);
  	inode->i_flags |= S_DEAD;
  out_up_write:
  	up_write(&root->fs_info->subvol_sem);
  out_unlock:
  	mutex_unlock(&inode->i_mutex);
  	if (!err) {
  		shrink_dcache_sb(root->fs_info->sb);
  		btrfs_invalidate_inodes(dest);
  		d_delete(dentry);
  	}
  out_dput:
  	dput(dentry);
  out_unlock_dir:
  	mutex_unlock(&dir->i_mutex);
  	mnt_drop_write(file->f_path.mnt);
  out:
  	kfree(vol_args);
  	return err;
  }
  
  static int btrfs_ioctl_defrag(struct file *file)
  {
  	struct inode *inode = fdentry(file)->d_inode;
  	struct btrfs_root *root = BTRFS_I(inode)->root;
  	int ret;
  
  	ret = mnt_want_write(file->f_path.mnt);
  	if (ret)
  		return ret;
  
  	switch (inode->i_mode & S_IFMT) {
  	case S_IFDIR:
  		if (!capable(CAP_SYS_ADMIN)) {
  			ret = -EPERM;
  			goto out;
  		}
  		btrfs_defrag_root(root, 0);
  		btrfs_defrag_root(root->fs_info->extent_root, 0);
  		break;
  	case S_IFREG:
  		if (!(file->f_mode & FMODE_WRITE)) {
  			ret = -EINVAL;
  			goto out;
  		}
  		btrfs_defrag_file(file);
  		break;
  	}
  out:
  	mnt_drop_write(file->f_path.mnt);
  	return ret;
  }
  
  static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
  {
  	struct btrfs_ioctl_vol_args *vol_args;
  	int ret;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	vol_args = memdup_user(arg, sizeof(*vol_args));
  	if (IS_ERR(vol_args))
  		return PTR_ERR(vol_args);
  
  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
  	ret = btrfs_init_new_device(root, vol_args->name);
  
  	kfree(vol_args);
  	return ret;
  }
  
  static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
  {
  	struct btrfs_ioctl_vol_args *vol_args;
  	int ret;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	if (root->fs_info->sb->s_flags & MS_RDONLY)
  		return -EROFS;
  
  	vol_args = memdup_user(arg, sizeof(*vol_args));
  	if (IS_ERR(vol_args))
  		return PTR_ERR(vol_args);
  
  	vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
  	ret = btrfs_rm_device(root, vol_args->name);
  
  	kfree(vol_args);
  	return ret;
  }
  
  static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
  				       u64 off, u64 olen, u64 destoff)
  {
  	struct inode *inode = fdentry(file)->d_inode;
  	struct btrfs_root *root = BTRFS_I(inode)->root;
  	struct file *src_file;
  	struct inode *src;
  	struct btrfs_trans_handle *trans;
  	struct btrfs_path *path;
  	struct extent_buffer *leaf;
  	char *buf;
  	struct btrfs_key key;
  	u32 nritems;
  	int slot;
  	int ret;
  	u64 len = olen;
  	u64 bs = root->fs_info->sb->s_blocksize;
  	u64 hint_byte;
  
  	/*
  	 * TODO:
  	 * - split compressed inline extents.  annoying: we need to
  	 *   decompress into destination's address_space (the file offset
  	 *   may change, so source mapping won't do), then recompress (or
  	 *   otherwise reinsert) a subrange.
  	 * - allow ranges within the same file to be cloned (provided
  	 *   they don't overlap)?
  	 */
  
  	/* the destination must be opened for writing */
  	if (!(file->f_mode & FMODE_WRITE))
  		return -EINVAL;
  
  	ret = mnt_want_write(file->f_path.mnt);
  	if (ret)
  		return ret;
  
  	src_file = fget(srcfd);
  	if (!src_file) {
  		ret = -EBADF;
  		goto out_drop_write;
  	}
  	src = src_file->f_dentry->d_inode;
  
  	ret = -EINVAL;
  	if (src == inode)
  		goto out_fput;
  
  	ret = -EISDIR;
  	if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
  		goto out_fput;
  
  	ret = -EXDEV;
  	if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
  		goto out_fput;
  
  	ret = -ENOMEM;
  	buf = vmalloc(btrfs_level_size(root, 0));
  	if (!buf)
  		goto out_fput;
  
  	path = btrfs_alloc_path();
  	if (!path) {
  		vfree(buf);
  		goto out_fput;
  	}
  	path->reada = 2;
  
  	if (inode < src) {
  		mutex_lock(&inode->i_mutex);
  		mutex_lock(&src->i_mutex);
  	} else {
  		mutex_lock(&src->i_mutex);
  		mutex_lock(&inode->i_mutex);
  	}
  
  	/* determine range to clone */
  	ret = -EINVAL;
  	if (off >= src->i_size || off + len > src->i_size)
  		goto out_unlock;
  	if (len == 0)
  		olen = len = src->i_size - off;
  	/* if we extend to eof, continue to block boundary */
  	if (off + len == src->i_size)
  		len = ((src->i_size + bs-1) & ~(bs-1))
  			- off;
  
  	/* verify the end result is block aligned */
  	if ((off & (bs-1)) ||
  	    ((off + len) & (bs-1)))
  		goto out_unlock;
  
  	/* do any pending delalloc/csum calc on src, one way or
  	   another, and lock file content */
  	while (1) {
  		struct btrfs_ordered_extent *ordered;
  		lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
  		ordered = btrfs_lookup_first_ordered_extent(inode, off+len);
  		if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
  			break;
  		unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
  		if (ordered)
  			btrfs_put_ordered_extent(ordered);
  		btrfs_wait_ordered_range(src, off, off+len);
  	}
  
  	trans = btrfs_start_transaction(root, 1);
  	BUG_ON(!trans);
  
  	/* punch hole in destination first */
  	btrfs_drop_extents(trans, root, inode, off, off + len,
  			   off + len, 0, &hint_byte, 1);
  
  	/* clone data */
  	key.objectid = src->i_ino;
  	key.type = BTRFS_EXTENT_DATA_KEY;
  	key.offset = 0;
  
  	while (1) {
  		/*
  		 * note the key will change type as we walk through the
  		 * tree.
  		 */
  		ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
  		if (ret < 0)
  			goto out;
  
  		nritems = btrfs_header_nritems(path->nodes[0]);
  		if (path->slots[0] >= nritems) {
  			ret = btrfs_next_leaf(root, path);
  			if (ret < 0)
  				goto out;
  			if (ret > 0)
  				break;
  			nritems = btrfs_header_nritems(path->nodes[0]);
  		}
  		leaf = path->nodes[0];
  		slot = path->slots[0];
  
  		btrfs_item_key_to_cpu(leaf, &key, slot);
  		if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
  		    key.objectid != src->i_ino)
  			break;
  
  		if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
  			struct btrfs_file_extent_item *extent;
  			int type;
  			u32 size;
  			struct btrfs_key new_key;
  			u64 disko = 0, diskl = 0;
  			u64 datao = 0, datal = 0;
  			u8 comp;
  
  			size = btrfs_item_size_nr(leaf, slot);
  			read_extent_buffer(leaf, buf,
  					   btrfs_item_ptr_offset(leaf, slot),
  					   size);
  
  			extent = btrfs_item_ptr(leaf, slot,
  						struct btrfs_file_extent_item);
  			comp = btrfs_file_extent_compression(leaf, extent);
  			type = btrfs_file_extent_type(leaf, extent);
  			if (type == BTRFS_FILE_EXTENT_REG ||
  			    type == BTRFS_FILE_EXTENT_PREALLOC) {
  				disko = btrfs_file_extent_disk_bytenr(leaf,
  								      extent);
  				diskl = btrfs_file_extent_disk_num_bytes(leaf,
  								 extent);
  				datao = btrfs_file_extent_offset(leaf, extent);
  				datal = btrfs_file_extent_num_bytes(leaf,
  								    extent);
  			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
  				/* take upper bound, may be compressed */
  				datal = btrfs_file_extent_ram_bytes(leaf,
  								    extent);
  			}
  			btrfs_release_path(root, path);
  
  			if (key.offset + datal < off ||
  			    key.offset >= off+len)
  				goto next;
  
  			memcpy(&new_key, &key, sizeof(new_key));
  			new_key.objectid = inode->i_ino;
  			new_key.offset = key.offset + destoff - off;
  
  			if (type == BTRFS_FILE_EXTENT_REG ||
  			    type == BTRFS_FILE_EXTENT_PREALLOC) {
  				ret = btrfs_insert_empty_item(trans, root, path,
  							      &new_key, size);
  				if (ret)
  					goto out;
  
  				leaf = path->nodes[0];
  				slot = path->slots[0];
  				write_extent_buffer(leaf, buf,
  					    btrfs_item_ptr_offset(leaf, slot),
  					    size);
  
  				extent = btrfs_item_ptr(leaf, slot,
  						struct btrfs_file_extent_item);
  
  				if (off > key.offset) {
  					datao += off - key.offset;
  					datal -= off - key.offset;
  				}
  
  				if (key.offset + datal > off + len)
  					datal = off + len - key.offset;
  
  				/* disko == 0 means it's a hole */
  				if (!disko)
  					datao = 0;
  
  				btrfs_set_file_extent_offset(leaf, extent,
  							     datao);
  				btrfs_set_file_extent_num_bytes(leaf, extent,
  								datal);
  				if (disko) {
  					inode_add_bytes(inode, datal);
  					ret = btrfs_inc_extent_ref(trans, root,
  							disko, diskl, 0,
  							root->root_key.objectid,
  							inode->i_ino,
  							new_key.offset - datao);
  					BUG_ON(ret);
  				}
  			} else if (type == BTRFS_FILE_EXTENT_INLINE) {
  				u64 skip = 0;
  				u64 trim = 0;
  				if (off > key.offset) {
  					skip = off - key.offset;
  					new_key.offset += skip;
  				}
  
  				if (key.offset + datal > off+len)
  					trim = key.offset + datal - (off+len);
  
  				if (comp && (skip || trim)) {
  					ret = -EINVAL;
  					goto out;
  				}
  				size -= skip + trim;
  				datal -= skip + trim;
  				ret = btrfs_insert_empty_item(trans, root, path,
  							      &new_key, size);
  				if (ret)
  					goto out;
  
  				if (skip) {
  					u32 start =
  					  btrfs_file_extent_calc_inline_size(0);
  					memmove(buf+start, buf+start+skip,
  						datal);
  				}
  
  				leaf = path->nodes[0];
  				slot = path->slots[0];
  				write_extent_buffer(leaf, buf,
  					    btrfs_item_ptr_offset(leaf, slot),
  					    size);
  				inode_add_bytes(inode, datal);
  			}
  
  			btrfs_mark_buffer_dirty(leaf);
  		}
  
  next:
  		btrfs_release_path(root, path);
  		key.offset++;
  	}
  	ret = 0;
  out:
  	btrfs_release_path(root, path);
  	if (ret == 0) {
  		inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  		if (destoff + olen > inode->i_size)
  			btrfs_i_size_write(inode, destoff + olen);
  		BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
  		ret = btrfs_update_inode(trans, root, inode);
  	}
  	btrfs_end_transaction(trans, root);
  	unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
  	if (ret)
  		vmtruncate(inode, 0);
  out_unlock:
  	mutex_unlock(&src->i_mutex);
  	mutex_unlock(&inode->i_mutex);
  	vfree(buf);
  	btrfs_free_path(path);
  out_fput:
  	fput(src_file);
  out_drop_write:
  	mnt_drop_write(file->f_path.mnt);
  	return ret;
  }
  
  static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
  {
  	struct btrfs_ioctl_clone_range_args args;
  
  	if (copy_from_user(&args, argp, sizeof(args)))
  		return -EFAULT;
  	return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
  				 args.src_length, args.dest_offset);
  }
  
  /*
   * there are many ways the trans_start and trans_end ioctls can lead
   * to deadlocks.  They should only be used by applications that
   * basically own the machine, and have a very in depth understanding
   * of all the possible deadlocks and enospc problems.
   */
  static long btrfs_ioctl_trans_start(struct file *file)
  {
  	struct inode *inode = fdentry(file)->d_inode;
  	struct btrfs_root *root = BTRFS_I(inode)->root;
  	struct btrfs_trans_handle *trans;
  	int ret;
  
  	ret = -EPERM;
  	if (!capable(CAP_SYS_ADMIN))
  		goto out;
  
  	ret = -EINPROGRESS;
  	if (file->private_data)
  		goto out;
  
  	ret = mnt_want_write(file->f_path.mnt);
  	if (ret)
  		goto out;
  
  	mutex_lock(&root->fs_info->trans_mutex);
  	root->fs_info->open_ioctl_trans++;
  	mutex_unlock(&root->fs_info->trans_mutex);
  
  	ret = -ENOMEM;
  	trans = btrfs_start_ioctl_transaction(root, 0);
  	if (!trans)
  		goto out_drop;
  
  	file->private_data = trans;
  	return 0;
  
  out_drop:
  	mutex_lock(&root->fs_info->trans_mutex);
  	root->fs_info->open_ioctl_trans--;
  	mutex_unlock(&root->fs_info->trans_mutex);
  	mnt_drop_write(file->f_path.mnt);
  out:
  	return ret;
  }
  
  /*
   * there are many ways the trans_start and trans_end ioctls can lead
   * to deadlocks.  They should only be used by applications that
   * basically own the machine, and have a very in depth understanding
   * of all the possible deadlocks and enospc problems.
   */
  long btrfs_ioctl_trans_end(struct file *file)
  {
  	struct inode *inode = fdentry(file)->d_inode;
  	struct btrfs_root *root = BTRFS_I(inode)->root;
  	struct btrfs_trans_handle *trans;
  
  	trans = file->private_data;
  	if (!trans)
  		return -EINVAL;
  	file->private_data = NULL;
  
  	btrfs_end_transaction(trans, root);
  
  	mutex_lock(&root->fs_info->trans_mutex);
  	root->fs_info->open_ioctl_trans--;
  	mutex_unlock(&root->fs_info->trans_mutex);
  
  	mnt_drop_write(file->f_path.mnt);
  	return 0;
  }
  
  long btrfs_ioctl(struct file *file, unsigned int
  		cmd, unsigned long arg)
  {
  	struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
  	void __user *argp = (void __user *)arg;
  
  	switch (cmd) {
  	case FS_IOC_GETFLAGS:
  		return btrfs_ioctl_getflags(file, argp);
  	case FS_IOC_SETFLAGS:
  		return btrfs_ioctl_setflags(file, argp);
  	case FS_IOC_GETVERSION:
  		return btrfs_ioctl_getversion(file, argp);
  	case BTRFS_IOC_SNAP_CREATE:
  		return btrfs_ioctl_snap_create(file, argp, 0);
  	case BTRFS_IOC_SUBVOL_CREATE:
  		return btrfs_ioctl_snap_create(file, argp, 1);
  	case BTRFS_IOC_SNAP_DESTROY:
  		return btrfs_ioctl_snap_destroy(file, argp);
  	case BTRFS_IOC_DEFRAG:
  		return btrfs_ioctl_defrag(file);
  	case BTRFS_IOC_RESIZE:
  		return btrfs_ioctl_resize(root, argp);
  	case BTRFS_IOC_ADD_DEV:
  		return btrfs_ioctl_add_dev(root, argp);
  	case BTRFS_IOC_RM_DEV:
  		return btrfs_ioctl_rm_dev(root, argp);
  	case BTRFS_IOC_BALANCE:
  		return btrfs_balance(root->fs_info->dev_root);
  	case BTRFS_IOC_CLONE:
  		return btrfs_ioctl_clone(file, arg, 0, 0, 0);
  	case BTRFS_IOC_CLONE_RANGE:
  		return btrfs_ioctl_clone_range(file, argp);
  	case BTRFS_IOC_TRANS_START:
  		return btrfs_ioctl_trans_start(file);
  	case BTRFS_IOC_TRANS_END:
  		return btrfs_ioctl_trans_end(file);
  	case BTRFS_IOC_SYNC:
  		btrfs_sync_fs(file->f_dentry->d_sb, 1);
  		return 0;
  	}
  
  	return -ENOTTY;
  }
  