11 files changed, 358 insertions, 8 deletions

diff --git a/Documentation/filesystems/nfs/pnfs-scsi-server.txt b/Documentation/filesystems/nfs/pnfs-scsi-server.txt
new file mode 100644
index 000000000000..5bef7268bd9f
--- /dev/null
+++ b/Documentation/filesystems/nfs/pnfs-scsi-server.txt
@@ -0,0 +1,23 @@
+
+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 a server built with CONFIG_NFSD_SCSI, the 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).
diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index eb70d91b255b..a30a31316e68 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 679cdc6efee8..3ae5f3c77e28 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 f00fa918e0f6..e55b5242614d 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"
@@ -159,6 +162,7 @@ nfsd4_block_get_device_info_simple(struct super_block *sb,
 
 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)
@@ -200,3 +204,205 @@ const struct nfsd4_layout_ops bl_layout_ops = {
         .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);
+                goto out_put_request;
+        }
+
+        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 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 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 6d834dc9bbc8..ca1883668810 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 6de925fe8499..397bc7563a49 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 4e4def77ebc7..825c7bc8d789 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 system supports exporting a block-like layout.
+         * If the block device supports reservations prefer the SCSI layout,
+         * otherwise 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 40b912407d51..de1ff1d98bb1 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1268,8 +1268,10 @@ 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 ff50bfa1f76f..7d073b9b1553 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 d68b62a76592..3542d94fddce 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 d85529ca299e..93f74853961b 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);