Re: [PATCH 4/4] nfsd: add SCSI layout support

["J. Bruce Fields" <bfields@fieldses.org>]

On Fri, Mar 04, 2016 at 08:46:17PM +0100, Christoph Hellwig wrote:
> This is a simple extension to the block layout driver to use SCSI
> persistent reservations for access control and fencing, as well as
> SCSI VPD pages for device identification.
> 
> For this we need to pass the nfs4_client to the proc_getdeviceinfo method
> to generate the reservation key, and add a new fence_client method
> to allow for fence actions in the layout driver.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  Documentation/filesystems/nfs/pnfs-scsi-server.txt |  22 ++
>  fs/nfsd/Kconfig                                    |  13 +
>  fs/nfsd/Makefile                                   |   1 +
>  fs/nfsd/blocklayout.c                              | 298 ++++++++++++++++++---
>  fs/nfsd/blocklayoutxdr.c                           |  65 ++++-
>  fs/nfsd/blocklayoutxdr.h                           |  14 +
>  fs/nfsd/nfs4layouts.c                              |  27 +-
>  fs/nfsd/nfs4proc.c                                 |   6 +-
>  fs/nfsd/pnfs.h                                     |   6 +
>  fs/xfs/Makefile                                    |   1 +
>  fs/xfs/xfs_pnfs.h                                  |   2 +-
>  11 files changed, 407 insertions(+), 48 deletions(-)
>  create mode 100644 Documentation/filesystems/nfs/pnfs-scsi-server.txt
> 
> diff --git a/Documentation/filesystems/nfs/pnfs-scsi-server.txt b/Documentation/filesystems/nfs/pnfs-scsi-server.txt
> new file mode 100644
> index 0000000..4150979
> --- /dev/null
> +++ b/Documentation/filesystems/nfs/pnfs-scsi-server.txt
> @@ -0,0 +1,22 @@
> +
> +pNFS SCSI layout server user guide
> +==================================
> +
> +This document describes support for pNFS SCSI layouts in the Linux NFS server.
> +With pNFS SCSI layouts, the NFS server acts as Metadata Server (MDS) for pNFS,
> +which in addition to handling all the metadata access to the NFS export,
> +also hands out layouts to the clients so that they can directly access the
> +underlying SCSI LUNs that are shared with the client.
> +
> +To use pNFS SCSI layouts with with the Linux NFS server, the exported file
> +system needs to support the pNFS SCSI layouts (currently just XFS), and the
> +file system must sit on a SCSI LUN that is accessible to the clients in
> +addition to the MDS.  As of now the file system needs to sit directly on the
> +exported LUN, striping or concatenation of LUNs on the MDS and clients
> +is not supported yet.
> +
> +On the server, pNFS SCSI volume support is automatically enabled if the
> +file system is exported using the "pnfs" option and the underlying SCSI
> +device support persistent reservations.  On the client make sure the kernel
> +has the CONFIG_PNFS_BLOCK option enabled, and the file system is mounted
> +using the NFSv4.1 protocol version (mount -o vers=4.1).

May as well document the server-side config there too, I guess; I'm
editing that like:

	On {+a server built with CONFIG_NFSD_SCSI,+} the[-server,-] pNFS
	SCSI volume support is

--b.

> diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
> index eb70d91..a30a313 100644
> --- a/fs/nfsd/Kconfig
> +++ b/fs/nfsd/Kconfig
> @@ -98,6 +98,19 @@ config NFSD_BLOCKLAYOUT
>  
>  	  If unsure, say N.
>  
> +config NFSD_SCSILAYOUT
> +	bool "NFSv4.1 server support for pNFS SCSI layouts"
> +	depends on NFSD_V4
> +	select NFSD_PNFS
> +	help
> +	  This option enables support for the exporting pNFS SCSI layouts
> +	  in the kernel's NFS server. The pNFS SCSI layout enables NFS
> +	  clients to directly perform I/O to SCSI devices accesible to both
> +	  the server and the clients.  See draft-ietf-nfsv4-scsi-layout for
> +	  more details.
> +
> +	  If unsure, say N.
> +
>  config NFSD_V4_SECURITY_LABEL
>  	bool "Provide Security Label support for NFSv4 server"
>  	depends on NFSD_V4 && SECURITY
> diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
> index 679cdc6..3ae5f3c 100644
> --- a/fs/nfsd/Makefile
> +++ b/fs/nfsd/Makefile
> @@ -19,3 +19,4 @@ nfsd-$(CONFIG_NFSD_V4)	+= nfs4proc.o nfs4xdr.o nfs4state.o nfs4idmap.o \
>  			   nfs4acl.o nfs4callback.o nfs4recover.o
>  nfsd-$(CONFIG_NFSD_PNFS) += nfs4layouts.o
>  nfsd-$(CONFIG_NFSD_BLOCKLAYOUT) += blocklayout.o blocklayoutxdr.o
> +nfsd-$(CONFIG_NFSD_SCSILAYOUT) += blocklayout.o blocklayoutxdr.o
> diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
> index c29d942..0e87e3e 100644
> --- a/fs/nfsd/blocklayout.c
> +++ b/fs/nfsd/blocklayout.c
> @@ -1,11 +1,14 @@
>  /*
> - * Copyright (c) 2014 Christoph Hellwig.
> + * Copyright (c) 2014-2016 Christoph Hellwig.
>   */
>  #include <linux/exportfs.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 "blocklayoutxdr.h"
>  #include "pnfs.h"
> @@ -13,37 +16,6 @@
>  #define NFSDDBG_FACILITY	NFSDDBG_PNFS
>  
>  
> -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 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_layoutget(struct inode *inode, const struct svc_fh *fhp,
>  		struct nfsd4_layoutget *args)
> @@ -141,20 +113,13 @@ out_layoutunavailable:
>  }
>  
>  static __be32
> -nfsd4_block_proc_layoutcommit(struct inode *inode,
> -		struct nfsd4_layoutcommit *lcp)
> +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 };
> -	struct iomap *iomaps;
> -	int nr_iomaps;
>  	int error;
>  
> -	nr_iomaps = nfsd4_block_decode_layoutupdate(lcp->lc_up_layout,
> -			lcp->lc_up_len, &iomaps, 1 << inode->i_blkbits);
> -	if (nr_iomaps < 0)
> -		return nfserrno(nr_iomaps);
> -
>  	if (lcp->lc_mtime.tv_nsec == UTIME_NOW ||
>  	    timespec_compare(&lcp->lc_mtime, &inode->i_mtime) < 0)
>  		lcp->lc_mtime = current_fs_time(inode->i_sb);
> @@ -172,6 +137,54 @@ nfsd4_block_proc_layoutcommit(struct inode *inode,
>  	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 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, 1 << inode->i_blkbits);
> +	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
> @@ -190,3 +203,206 @@ const struct nfsd4_layout_ops bl_layout_ops = {
>  	.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;
> +	size_t bufflen = 252, len, id_len;
> +	u8 *buf, *d, type, assoc;
> +	int error;
> +
> +	buf = kzalloc(bufflen, GFP_KERNEL);
> +	if (!buf)
> +		return -ENOMEM;
> +
> +	rq = blk_get_request(q, READ, GFP_KERNEL);
> +	if (IS_ERR(rq)) {
> +		error = -ENOMEM;
> +		goto out_free_buf;
> +	}
> +	blk_rq_set_block_pc(rq);
> +
> +	error = blk_rq_map_kern(q, rq, buf, bufflen, GFP_KERNEL);
> +	if (error)
> +		goto out_put_request;
> +
> +	rq->cmd[0] = INQUIRY;
> +	rq->cmd[1] = 1;
> +	rq->cmd[2] = 0x83;
> +	rq->cmd[3] = bufflen >> 8;
> +	rq->cmd[4] = bufflen & 0xff;
> +	rq->cmd_len = COMMAND_SIZE(INQUIRY);
> +
> +	error = blk_execute_rq(rq->q, NULL, rq, 1);
> +	if (error) {
> +		pr_err("pNFS: INQUIRY 0x83 failed with: %x\n",
> +			rq->errors);
> +		
> +	}
> +
> +	len = (buf[2] << 8) + buf[3] + 4;
> +	if (len > bufflen) {
> +		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		0x0100000000000000
> +
> +/*
> + * We use the client ID as a uniqueue 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 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, 1 << inode->i_blkbits);
> +	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 */
> diff --git a/fs/nfsd/blocklayoutxdr.c b/fs/nfsd/blocklayoutxdr.c
> index 6d834dc..ca18836 100644
> --- a/fs/nfsd/blocklayoutxdr.c
> +++ b/fs/nfsd/blocklayoutxdr.c
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2014 Christoph Hellwig.
> + * Copyright (c) 2014-2016 Christoph Hellwig.
>   */
>  #include <linux/sunrpc/svc.h>
>  #include <linux/exportfs.h>
> @@ -53,6 +53,18 @@ nfsd4_block_encode_volume(struct xdr_stream *xdr, struct pnfs_block_volume *b)
>  		p = xdr_encode_hyper(p, b->simple.offset);
>  		p = xdr_encode_opaque(p, b->simple.sig, b->simple.sig_len);
>  		break;
> +	case PNFS_BLOCK_VOLUME_SCSI:
> +		len = 4 + 4 + 4 + 4 + b->scsi.designator_len + 8;
> +		p = xdr_reserve_space(xdr, len);
> +		if (!p)
> +			return -ETOOSMALL;
> +
> +		*p++ = cpu_to_be32(b->type);
> +		*p++ = cpu_to_be32(b->scsi.code_set);
> +		*p++ = cpu_to_be32(b->scsi.designator_type);
> +		p = xdr_encode_opaque(p, b->scsi.designator, b->scsi.designator_len);
> +		p = xdr_encode_hyper(p, b->scsi.pr_key);
> +		break;
>  	default:
>  		return -ENOTSUPP;
>  	}
> @@ -155,3 +167,54 @@ fail:
>  	kfree(iomaps);
>  	return -EINVAL;
>  }
> +
> +int
> +nfsd4_scsi_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
> +		u32 block_size)
> +{
> +	struct iomap *iomaps;
> +	u32 nr_iomaps, expected, i;
> +
> +	if (len < sizeof(u32)) {
> +		dprintk("%s: extent array too small: %u\n", __func__, len);
> +		return -EINVAL;
> +	}
> +
> +	nr_iomaps = be32_to_cpup(p++);
> +	expected = sizeof(__be32) + nr_iomaps * PNFS_SCSI_RANGE_SIZE;
> +	if (len != expected) {
> +		dprintk("%s: extent array size mismatch: %u/%u\n",
> +			__func__, len, expected);
> +		return -EINVAL;
> +	}
> +
> +	iomaps = kcalloc(nr_iomaps, sizeof(*iomaps), GFP_KERNEL);
> +	if (!iomaps) {
> +		dprintk("%s: failed to allocate extent array\n", __func__);
> +		return -ENOMEM;
> +	}
> +
> +	for (i = 0; i < nr_iomaps; i++) {
> +		u64 val;
> +
> +		p = xdr_decode_hyper(p, &val);
> +		if (val & (block_size - 1)) {
> +			dprintk("%s: unaligned offset 0x%llx\n", __func__, val);
> +			goto fail;
> +		}
> +		iomaps[i].offset = val;
> +
> +		p = xdr_decode_hyper(p, &val);
> +		if (val & (block_size - 1)) {
> +			dprintk("%s: unaligned length 0x%llx\n", __func__, val);
> +			goto fail;
> +		}
> +		iomaps[i].length = val;
> +	}
> +
> +	*iomapp = iomaps;
> +	return nr_iomaps;
> +fail:
> +	kfree(iomaps);
> +	return -EINVAL;
> +}
> diff --git a/fs/nfsd/blocklayoutxdr.h b/fs/nfsd/blocklayoutxdr.h
> index 6de925f..397bc75 100644
> --- a/fs/nfsd/blocklayoutxdr.h
> +++ b/fs/nfsd/blocklayoutxdr.h
> @@ -15,6 +15,11 @@ struct pnfs_block_extent {
>  	enum pnfs_block_extent_state	es;
>  };
>  
> +struct pnfs_block_range {
> +	u64				foff;
> +	u64				len;
> +};
> +
>  /*
>   * Random upper cap for the uuid length to avoid unbounded allocation.
>   * Not actually limited by the protocol.
> @@ -29,6 +34,13 @@ struct pnfs_block_volume {
>  			u32		sig_len;
>  			u8		sig[PNFS_BLOCK_UUID_LEN];
>  		} simple;
> +		struct {
> +			enum scsi_code_set		code_set;
> +			enum scsi_designator_type	designator_type;
> +			int				designator_len;
> +			u8				designator[256];
> +			u64				pr_key;
> +		} scsi;
>  	};
>  };
>  
> @@ -43,5 +55,7 @@ __be32 nfsd4_block_encode_layoutget(struct xdr_stream *xdr,
>  		struct nfsd4_layoutget *lgp);
>  int nfsd4_block_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
>  		u32 block_size);
> +int nfsd4_scsi_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp,
> +		u32 block_size);
>  
>  #endif /* _NFSD_BLOCKLAYOUTXDR_H */
> diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
> index 4e4def7..cbd804e 100644
> --- a/fs/nfsd/nfs4layouts.c
> +++ b/fs/nfsd/nfs4layouts.c
> @@ -1,6 +1,7 @@
>  /*
>   * Copyright (c) 2014 Christoph Hellwig.
>   */
> +#include <linux/blkdev.h>
>  #include <linux/kmod.h>
>  #include <linux/file.h>
>  #include <linux/jhash.h>
> @@ -29,6 +30,9 @@ const struct nfsd4_layout_ops *nfsd4_layout_ops[LAYOUT_TYPE_MAX] =  {
>  #ifdef CONFIG_NFSD_BLOCKLAYOUT
>  	[LAYOUT_BLOCK_VOLUME]	= &bl_layout_ops,
>  #endif
> +#ifdef CONFIG_NFSD_SCSILAYOUT
> +	[LAYOUT_SCSI]		= &scsi_layout_ops,
> +#endif
>  };
>  
>  /* pNFS device ID to export fsid mapping */
> @@ -123,12 +127,24 @@ void nfsd4_setup_layout_type(struct svc_export *exp)
>  	if (!(exp->ex_flags & NFSEXP_PNFS))
>  		return;
>  
> +	/*
> +	 * Check if the file systems supports exporting a block-like layout.
> +	 * If the block device supports reservations prefer the SCSI layout,
> +	 * else advertise the block layout.
> +	 */
>  #ifdef CONFIG_NFSD_BLOCKLAYOUT
>  	if (sb->s_export_op->get_uuid &&
>  	    sb->s_export_op->map_blocks &&
>  	    sb->s_export_op->commit_blocks)
>  		exp->ex_layout_type = LAYOUT_BLOCK_VOLUME;
>  #endif
> +#ifdef CONFIG_NFSD_SCSILAYOUT
> +	/* overwrite block layout selection if needed */
> +	if (sb->s_export_op->map_blocks &&
> +	    sb->s_export_op->commit_blocks &&
> +	    sb->s_bdev && sb->s_bdev->bd_disk->fops->pr_ops)
> +		exp->ex_layout_type = LAYOUT_SCSI;
> +#endif
>  }
>  
>  static void
> @@ -594,8 +610,6 @@ nfsd4_cb_layout_fail(struct nfs4_layout_stateid *ls)
>  
>  	rpc_ntop((struct sockaddr *)&clp->cl_addr, addr_str, sizeof(addr_str));
>  
> -	trace_layout_recall_fail(&ls->ls_stid.sc_stateid);
> -
>  	printk(KERN_WARNING
>  		"nfsd: client %s failed to respond to layout recall. "
>  		"  Fencing..\n", addr_str);
> @@ -630,6 +644,7 @@ nfsd4_cb_layout_done(struct nfsd4_callback *cb, struct rpc_task *task)
>  		container_of(cb, struct nfs4_layout_stateid, ls_recall);
>  	struct nfsd_net *nn;
>  	ktime_t now, cutoff;
> +	const struct nfsd4_layout_ops *ops;
>  	LIST_HEAD(reaplist);
>  
>  
> @@ -665,7 +680,13 @@ nfsd4_cb_layout_done(struct nfsd4_callback *cb, struct rpc_task *task)
>  		/*
>  		 * Unknown error or non-responding client, we'll need to fence.
>  		 */
> -		nfsd4_cb_layout_fail(ls);
> +		trace_layout_recall_fail(&ls->ls_stid.sc_stateid);
> +
> +		ops = nfsd4_layout_ops[ls->ls_layout_type];
> +		if (ops->fence_client)
> +			ops->fence_client(ls);
> +		else
> +			nfsd4_cb_layout_fail(ls);
>  		return -1;
>  	}
>  }
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 4cba786..629443e 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1269,8 +1269,10 @@ nfsd4_getdeviceinfo(struct svc_rqst *rqstp,
>  		goto out;
>  
>  	nfserr = nfs_ok;
> -	if (gdp->gd_maxcount != 0)
> -		nfserr = ops->proc_getdeviceinfo(exp->ex_path.mnt->mnt_sb, gdp);
> +	if (gdp->gd_maxcount != 0) {
> +		nfserr = ops->proc_getdeviceinfo(exp->ex_path.mnt->mnt_sb,
> +					cstate->session->se_client, gdp);
> +	}
>  
>  	gdp->gd_notify_types &= ops->notify_types;
>  out:
> diff --git a/fs/nfsd/pnfs.h b/fs/nfsd/pnfs.h
> index ff50bfa..7d073b9 100644
> --- a/fs/nfsd/pnfs.h
> +++ b/fs/nfsd/pnfs.h
> @@ -21,6 +21,7 @@ struct nfsd4_layout_ops {
>  	u32		notify_types;
>  
>  	__be32 (*proc_getdeviceinfo)(struct super_block *sb,
> +			struct nfs4_client *clp,
>  			struct nfsd4_getdeviceinfo *gdevp);
>  	__be32 (*encode_getdeviceinfo)(struct xdr_stream *xdr,
>  			struct nfsd4_getdeviceinfo *gdevp);
> @@ -32,12 +33,17 @@ struct nfsd4_layout_ops {
>  
>  	__be32 (*proc_layoutcommit)(struct inode *inode,
>  			struct nfsd4_layoutcommit *lcp);
> +
> +	void (*fence_client)(struct nfs4_layout_stateid *ls);
>  };
>  
>  extern const struct nfsd4_layout_ops *nfsd4_layout_ops[];
>  #ifdef CONFIG_NFSD_BLOCKLAYOUT
>  extern const struct nfsd4_layout_ops bl_layout_ops;
>  #endif
> +#ifdef CONFIG_NFSD_SCSILAYOUT
> +extern const struct nfsd4_layout_ops scsi_layout_ops;
> +#endif
>  
>  __be32 nfsd4_preprocess_layout_stateid(struct svc_rqst *rqstp,
>  		struct nfsd4_compound_state *cstate, stateid_t *stateid,
> diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
> index d68b62a..3542d94 100644
> --- a/fs/xfs/Makefile
> +++ b/fs/xfs/Makefile
> @@ -122,3 +122,4 @@ xfs-$(CONFIG_XFS_POSIX_ACL)	+= xfs_acl.o
>  xfs-$(CONFIG_SYSCTL)		+= xfs_sysctl.o
>  xfs-$(CONFIG_COMPAT)		+= xfs_ioctl32.o
>  xfs-$(CONFIG_NFSD_BLOCKLAYOUT)	+= xfs_pnfs.o
> +xfs-$(CONFIG_NFSD_SCSILAYOUT)	+= xfs_pnfs.o
> diff --git a/fs/xfs/xfs_pnfs.h b/fs/xfs/xfs_pnfs.h
> index d85529c..93f7485 100644
> --- a/fs/xfs/xfs_pnfs.h
> +++ b/fs/xfs/xfs_pnfs.h
> @@ -1,7 +1,7 @@
>  #ifndef _XFS_PNFS_H
>  #define _XFS_PNFS_H 1
>  
> -#ifdef CONFIG_NFSD_BLOCKLAYOUT
> +#if defined(CONFIG_NFSD_BLOCKLAYOUT) || defined(CONFIG_NFSD_SCSILAYOUT)
>  int xfs_fs_get_uuid(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
>  int xfs_fs_map_blocks(struct inode *inode, loff_t offset, u64 length,
>  		struct iomap *iomap, bool write, u32 *device_generation);
> -- 
> 2.1.4