text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Copyright (c) 2014-2016 Christoph Hellwig.
   */
  #include <linux/exportfs.h>
  #include <linux/iomap.h>
  #include <linux/genhd.h>
  #include <linux/slab.h>
  #include <linux/pr.h>
  
  #include <linux/nfsd/debug.h>
  #include <scsi/scsi_proto.h>
  #include <scsi/scsi_common.h>
  #include <scsi/scsi_request.h>
  
  #include "blocklayoutxdr.h"
  #include "pnfs.h"
  
  #define NFSDDBG_FACILITY	NFSDDBG_PNFS
  
  
  static __be32
  nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
  		struct nfsd4_layoutget *args)
  {
  	struct nfsd4_layout_seg *seg = &args->lg_seg;
  	struct super_block *sb = inode->i_sb;
  	u32 block_size = i_blocksize(inode);
  	struct pnfs_block_extent *bex;
  	struct iomap iomap;
  	u32 device_generation = 0;
  	int error;
  
  	if (seg->offset & (block_size - 1)) {
  		dprintk("pnfsd: I/O misaligned\n");
  		goto out_layoutunavailable;
  	}
  
  	/*
  	 * Some clients barf on non-zero block numbers for NONE or INVALID
  	 * layouts, so make sure to zero the whole structure.
  	 */
  	error = -ENOMEM;
  	bex = kzalloc(sizeof(*bex), GFP_KERNEL);
  	if (!bex)
  		goto out_error;
  	args->lg_content = bex;
  
  	error = sb->s_export_op->map_blocks(inode, seg->offset, seg->length,
  					    &iomap, seg->iomode != IOMODE_READ,
  					    &device_generation);
  	if (error) {
  		if (error == -ENXIO)
  			goto out_layoutunavailable;
  		goto out_error;
  	}
  
  	if (iomap.length < args->lg_minlength) {
  		dprintk("pnfsd: extent smaller than minlength\n");
  		goto out_layoutunavailable;
  	}
  
  	switch (iomap.type) {
  	case IOMAP_MAPPED:
  		if (seg->iomode == IOMODE_READ)
  			bex->es = PNFS_BLOCK_READ_DATA;
  		else
  			bex->es = PNFS_BLOCK_READWRITE_DATA;
  		bex->soff = iomap.addr;
  		break;
  	case IOMAP_UNWRITTEN:
  		if (seg->iomode & IOMODE_RW) {
  			/*
  			 * Crack monkey special case from section 2.3.1.
  			 */
  			if (args->lg_minlength == 0) {
  				dprintk("pnfsd: no soup for you!\n");
  				goto out_layoutunavailable;
  			}
  
  			bex->es = PNFS_BLOCK_INVALID_DATA;
  			bex->soff = iomap.addr;
  			break;
  		}
  		/*FALLTHRU*/
  	case IOMAP_HOLE:
  		if (seg->iomode == IOMODE_READ) {
  			bex->es = PNFS_BLOCK_NONE_DATA;
  			break;
  		}
  		/*FALLTHRU*/
  	case IOMAP_DELALLOC:
  	default:
  		WARN(1, "pnfsd: filesystem returned %d extent\n", iomap.type);
  		goto out_layoutunavailable;
  	}
  
  	error = nfsd4_set_deviceid(&bex->vol_id, fhp, device_generation);
  	if (error)
  		goto out_error;
  	bex->foff = iomap.offset;
  	bex->len = iomap.length;
  
  	seg->offset = iomap.offset;
  	seg->length = iomap.length;
  
  	dprintk("GET: 0x%llx:0x%llx %d\n", bex->foff, bex->len, bex->es);
  	return 0;
  
  out_error:
  	seg->length = 0;
  	return nfserrno(error);
  out_layoutunavailable:
  	seg->length = 0;
  	return nfserr_layoutunavailable;
  }
  
  static __be32
  nfsd4_block_commit_blocks(struct inode *inode, struct nfsd4_layoutcommit *lcp,
  		struct iomap *iomaps, int nr_iomaps)
  {
  	loff_t new_size = lcp->lc_last_wr + 1;
  	struct iattr iattr = { .ia_valid = 0 };
  	int error;
  
  	if (lcp->lc_mtime.tv_nsec == UTIME_NOW ||
  	    timespec64_compare(&lcp->lc_mtime, &inode->i_mtime) < 0)
  		lcp->lc_mtime = current_time(inode);
  	iattr.ia_valid |= ATTR_ATIME | ATTR_CTIME | ATTR_MTIME;
  	iattr.ia_atime = iattr.ia_ctime = iattr.ia_mtime = lcp->lc_mtime;
  
  	if (new_size > i_size_read(inode)) {
  		iattr.ia_valid |= ATTR_SIZE;
  		iattr.ia_size = new_size;
  	}
  
  	error = inode->i_sb->s_export_op->commit_blocks(inode, iomaps,
  			nr_iomaps, &iattr);
  	kfree(iomaps);
  	return nfserrno(error);
  }
  
  #ifdef CONFIG_NFSD_BLOCKLAYOUT
  static int
  nfsd4_block_get_device_info_simple(struct super_block *sb,
  		struct nfsd4_getdeviceinfo *gdp)
  {
  	struct pnfs_block_deviceaddr *dev;
  	struct pnfs_block_volume *b;
  
  	dev = kzalloc(sizeof(struct pnfs_block_deviceaddr) +
  		      sizeof(struct pnfs_block_volume), GFP_KERNEL);
  	if (!dev)
  		return -ENOMEM;
  	gdp->gd_device = dev;
  
  	dev->nr_volumes = 1;
  	b = &dev->volumes[0];
  
  	b->type = PNFS_BLOCK_VOLUME_SIMPLE;
  	b->simple.sig_len = PNFS_BLOCK_UUID_LEN;
  	return sb->s_export_op->get_uuid(sb, b->simple.sig, &b->simple.sig_len,
  			&b->simple.offset);
  }
  
  static __be32
  nfsd4_block_proc_getdeviceinfo(struct super_block *sb,
  		struct svc_rqst *rqstp,
  		struct nfs4_client *clp,
  		struct nfsd4_getdeviceinfo *gdp)
  {
  	if (sb->s_bdev != sb->s_bdev->bd_contains)
  		return nfserr_inval;
  	return nfserrno(nfsd4_block_get_device_info_simple(sb, gdp));
  }
  
  static __be32
  nfsd4_block_proc_layoutcommit(struct inode *inode,
  		struct nfsd4_layoutcommit *lcp)
  {
  	struct iomap *iomaps;
  	int nr_iomaps;
  
  	nr_iomaps = nfsd4_block_decode_layoutupdate(lcp->lc_up_layout,
  			lcp->lc_up_len, &iomaps, i_blocksize(inode));
  	if (nr_iomaps < 0)
  		return nfserrno(nr_iomaps);
  
  	return nfsd4_block_commit_blocks(inode, lcp, iomaps, nr_iomaps);
  }
  
  const struct nfsd4_layout_ops bl_layout_ops = {
  	/*
  	 * Pretend that we send notification to the client.  This is a blatant
  	 * lie to force recent Linux clients to cache our device IDs.
  	 * We rarely ever change the device ID, so the harm of leaking deviceids
  	 * for a while isn't too bad.  Unfortunately RFC5661 is a complete mess
  	 * in this regard, but I filed errata 4119 for this a while ago, and
  	 * hopefully the Linux client will eventually start caching deviceids
  	 * without this again.
  	 */
  	.notify_types		=
  			NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
  	.proc_getdeviceinfo	= nfsd4_block_proc_getdeviceinfo,
  	.encode_getdeviceinfo	= nfsd4_block_encode_getdeviceinfo,
  	.proc_layoutget		= nfsd4_block_proc_layoutget,
  	.encode_layoutget	= nfsd4_block_encode_layoutget,
  	.proc_layoutcommit	= nfsd4_block_proc_layoutcommit,
  };
  #endif /* CONFIG_NFSD_BLOCKLAYOUT */
  
  #ifdef CONFIG_NFSD_SCSILAYOUT
  static int nfsd4_scsi_identify_device(struct block_device *bdev,
  		struct pnfs_block_volume *b)
  {
  	struct request_queue *q = bdev->bd_disk->queue;
  	struct request *rq;
  	struct scsi_request *req;
  	/*
  	 * The allocation length (passed in bytes 3 and 4 of the INQUIRY
  	 * command descriptor block) specifies the number of bytes that have
  	 * been allocated for the data-in buffer.
  	 * 252 is the highest one-byte value that is a multiple of 4.
  	 * 65532 is the highest two-byte value that is a multiple of 4.
  	 */
  	size_t bufflen = 252, maxlen = 65532, len, id_len;
  	u8 *buf, *d, type, assoc;
  	int retries = 1, error;
  
  	if (WARN_ON_ONCE(!blk_queue_scsi_passthrough(q)))
  		return -EINVAL;
  
  again:
  	buf = kzalloc(bufflen, GFP_KERNEL);
  	if (!buf)
  		return -ENOMEM;
  
  	rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
  	if (IS_ERR(rq)) {
  		error = -ENOMEM;
  		goto out_free_buf;
  	}
  	req = scsi_req(rq);
  
  	error = blk_rq_map_kern(q, rq, buf, bufflen, GFP_KERNEL);
  	if (error)
  		goto out_put_request;
  
  	req->cmd[0] = INQUIRY;
  	req->cmd[1] = 1;
  	req->cmd[2] = 0x83;
  	req->cmd[3] = bufflen >> 8;
  	req->cmd[4] = bufflen & 0xff;
  	req->cmd_len = COMMAND_SIZE(INQUIRY);
  
  	blk_execute_rq(rq->q, NULL, rq, 1);
  	if (req->result) {
  		pr_err("pNFS: INQUIRY 0x83 failed with: %x\n",
  			req->result);
  		error = -EIO;
  		goto out_put_request;
  	}
  
  	len = (buf[2] << 8) + buf[3] + 4;
  	if (len > bufflen) {
  		if (len <= maxlen && retries--) {
  			blk_put_request(rq);
  			kfree(buf);
  			bufflen = len;
  			goto again;
  		}
  		pr_err("pNFS: INQUIRY 0x83 response invalid (len = %zd)\n",
  			len);
  		goto out_put_request;
  	}
  
  	d = buf + 4;
  	for (d = buf + 4; d < buf + len; d += id_len + 4) {
  		id_len = d[3];
  		type = d[1] & 0xf;
  		assoc = (d[1] >> 4) & 0x3;
  
  		/*
  		 * We only care about a EUI-64 and NAA designator types
  		 * with LU association.
  		 */
  		if (assoc != 0x00)
  			continue;
  		if (type != 0x02 && type != 0x03)
  			continue;
  		if (id_len != 8 && id_len != 12 && id_len != 16)
  			continue;
  
  		b->scsi.code_set = PS_CODE_SET_BINARY;
  		b->scsi.designator_type = type == 0x02 ?
  			PS_DESIGNATOR_EUI64 : PS_DESIGNATOR_NAA;
  		b->scsi.designator_len = id_len;
  		memcpy(b->scsi.designator, d + 4, id_len);
  
  		/*
  		 * If we found a 8 or 12 byte descriptor continue on to
  		 * see if a 16 byte one is available.  If we find a
  		 * 16 byte descriptor we're done.
  		 */
  		if (id_len == 16)
  			break;
  	}
  
  out_put_request:
  	blk_put_request(rq);
  out_free_buf:
  	kfree(buf);
  	return error;
  }
  
  #define NFSD_MDS_PR_KEY		0x0100000000000000ULL
  
  /*
   * We use the client ID as a unique key for the reservations.
   * This allows us to easily fence a client when recalls fail.
   */
  static u64 nfsd4_scsi_pr_key(struct nfs4_client *clp)
  {
  	return ((u64)clp->cl_clientid.cl_boot << 32) | clp->cl_clientid.cl_id;
  }
  
  static int
  nfsd4_block_get_device_info_scsi(struct super_block *sb,
  		struct nfs4_client *clp,
  		struct nfsd4_getdeviceinfo *gdp)
  {
  	struct pnfs_block_deviceaddr *dev;
  	struct pnfs_block_volume *b;
  	const struct pr_ops *ops;
  	int error;
  
  	dev = kzalloc(sizeof(struct pnfs_block_deviceaddr) +
  		      sizeof(struct pnfs_block_volume), GFP_KERNEL);
  	if (!dev)
  		return -ENOMEM;
  	gdp->gd_device = dev;
  
  	dev->nr_volumes = 1;
  	b = &dev->volumes[0];
  
  	b->type = PNFS_BLOCK_VOLUME_SCSI;
  	b->scsi.pr_key = nfsd4_scsi_pr_key(clp);
  
  	error = nfsd4_scsi_identify_device(sb->s_bdev, b);
  	if (error)
  		return error;
  
  	ops = sb->s_bdev->bd_disk->fops->pr_ops;
  	if (!ops) {
  		pr_err("pNFS: device %s does not support PRs.\n",
  			sb->s_id);
  		return -EINVAL;
  	}
  
  	error = ops->pr_register(sb->s_bdev, 0, NFSD_MDS_PR_KEY, true);
  	if (error) {
  		pr_err("pNFS: failed to register key for device %s.\n",
  			sb->s_id);
  		return -EINVAL;
  	}
  
  	error = ops->pr_reserve(sb->s_bdev, NFSD_MDS_PR_KEY,
  			PR_EXCLUSIVE_ACCESS_REG_ONLY, 0);
  	if (error) {
  		pr_err("pNFS: failed to reserve device %s.\n",
  			sb->s_id);
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static __be32
  nfsd4_scsi_proc_getdeviceinfo(struct super_block *sb,
  		struct svc_rqst *rqstp,
  		struct nfs4_client *clp,
  		struct nfsd4_getdeviceinfo *gdp)
  {
  	if (sb->s_bdev != sb->s_bdev->bd_contains)
  		return nfserr_inval;
  	return nfserrno(nfsd4_block_get_device_info_scsi(sb, clp, gdp));
  }
  static __be32
  nfsd4_scsi_proc_layoutcommit(struct inode *inode,
  		struct nfsd4_layoutcommit *lcp)
  {
  	struct iomap *iomaps;
  	int nr_iomaps;
  
  	nr_iomaps = nfsd4_scsi_decode_layoutupdate(lcp->lc_up_layout,
  			lcp->lc_up_len, &iomaps, i_blocksize(inode));
  	if (nr_iomaps < 0)
  		return nfserrno(nr_iomaps);
  
  	return nfsd4_block_commit_blocks(inode, lcp, iomaps, nr_iomaps);
  }
  
  static void
  nfsd4_scsi_fence_client(struct nfs4_layout_stateid *ls)
  {
  	struct nfs4_client *clp = ls->ls_stid.sc_client;
  	struct block_device *bdev = ls->ls_file->f_path.mnt->mnt_sb->s_bdev;
  
  	bdev->bd_disk->fops->pr_ops->pr_preempt(bdev, NFSD_MDS_PR_KEY,
  			nfsd4_scsi_pr_key(clp), 0, true);
  }
  
  const struct nfsd4_layout_ops scsi_layout_ops = {
  	/*
  	 * Pretend that we send notification to the client.  This is a blatant
  	 * lie to force recent Linux clients to cache our device IDs.
  	 * We rarely ever change the device ID, so the harm of leaking deviceids
  	 * for a while isn't too bad.  Unfortunately RFC5661 is a complete mess
  	 * in this regard, but I filed errata 4119 for this a while ago, and
  	 * hopefully the Linux client will eventually start caching deviceids
  	 * without this again.
  	 */
  	.notify_types		=
  			NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
  	.proc_getdeviceinfo	= nfsd4_scsi_proc_getdeviceinfo,
  	.encode_getdeviceinfo	= nfsd4_block_encode_getdeviceinfo,
  	.proc_layoutget		= nfsd4_block_proc_layoutget,
  	.encode_layoutget	= nfsd4_block_encode_layoutget,
  	.proc_layoutcommit	= nfsd4_scsi_proc_layoutcommit,
  	.fence_client		= nfsd4_scsi_fence_client,
  };
  #endif /* CONFIG_NFSD_SCSILAYOUT */
  