[PATCH 4/7] nfsd: support multiple pNFS device IDs

[Christoph Hellwig <hch@lst.de>]

Add support for a device index in the device ID so that we can support
multiple different devices and not just different generations when
the devids are refreshed.  This will be used for block layout exports
of multi-device file systems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/nfsd/blocklayout.c    | 2 +-
 fs/nfsd/flexfilelayout.c | 3 +--
 fs/nfsd/nfs4layouts.c    | 3 ++-
 fs/nfsd/pnfs.h           | 2 +-
 fs/nfsd/xdr4.h           | 5 +++--
 5 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index 0dd36f3d5a51..8ca8fd8f70cb 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -75,7 +75,7 @@ nfsd4_block_map_extent(struct inode *inode, const struct svc_fh *fhp,
 		return nfserr_layoutunavailable;
 	}
 
-	error = nfsd4_set_deviceid(&bex->vol_id, fhp, device_generation);
+	error = nfsd4_set_deviceid(&bex->vol_id, fhp, 0, device_generation);
 	if (error)
 		return nfserrno(error);
 
diff --git a/fs/nfsd/flexfilelayout.c b/fs/nfsd/flexfilelayout.c
index 6d531285ab43..b57db4b4dda7 100644
--- a/fs/nfsd/flexfilelayout.c
+++ b/fs/nfsd/flexfilelayout.c
@@ -24,7 +24,6 @@ nfsd4_ff_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
 		const struct svc_fh *fhp, struct nfsd4_layoutget *args)
 {
 	struct nfsd4_layout_seg *seg = &args->lg_seg;
-	u32 device_generation = 0;
 	int error;
 	uid_t u;
 
@@ -57,7 +56,7 @@ nfsd4_ff_proc_layoutget(struct svc_rqst *rqstp, struct inode *inode,
 		fl->uid = inode->i_uid;
 	fl->gid = inode->i_gid;
 
-	error = nfsd4_set_deviceid(&fl->deviceid, fhp, device_generation);
+	error = nfsd4_set_deviceid(&fl->deviceid, fhp, 0, 0);
 	if (error)
 		goto out_error;
 
diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index 7b849b637b5e..ace6057f5d63 100644
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -110,7 +110,7 @@ nfsd4_find_devid_map(int idx)
 
 int
 nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp,
-		u32 device_generation)
+		u32 dev_idx, u32 device_generation)
 {
 	if (!fhp->fh_export->ex_devid_map) {
 		nfsd4_alloc_devid_map(fhp);
@@ -120,6 +120,7 @@ nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp,
 
 	id->fsid_idx = fhp->fh_export->ex_devid_map->idx;
 	id->generation = device_generation;
+	id->dev_idx = dev_idx;
 	return 0;
 }
 
diff --git a/fs/nfsd/pnfs.h b/fs/nfsd/pnfs.h
index db9af780438b..4a6b0ad2ec9b 100644
--- a/fs/nfsd/pnfs.h
+++ b/fs/nfsd/pnfs.h
@@ -65,7 +65,7 @@ __be32 nfsd4_return_client_layouts(struct svc_rqst *rqstp,
 		struct nfsd4_compound_state *cstate,
 		struct nfsd4_layoutreturn *lrp);
 int nfsd4_set_deviceid(struct nfsd4_deviceid *id, const struct svc_fh *fhp,
-		u32 device_generation);
+		u32 dev_idx, u32 device_generation);
 struct nfsd4_deviceid_map *nfsd4_find_devid_map(int idx);
 #endif /* CONFIG_NFSD_V4 */
 
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 417e9ad9fbb3..ddeba134b9af 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -602,6 +602,7 @@ struct nfsd4_reclaim_complete {
 struct nfsd4_deviceid {
 	u64			fsid_idx;
 	u32			generation;
+	u32			dev_idx;
 };
 
 static inline __be32 *
@@ -612,7 +613,7 @@ svcxdr_encode_deviceid4(__be32 *p, const struct nfsd4_deviceid *devid)
 	*q = (__force __be64)devid->fsid_idx;
 	p += 2;
 	*p++ = (__force __be32)devid->generation;
-	*p++ = xdr_zero;
+	*p++ = (__force __be32)devid->dev_idx;
 	return p;
 }
 
@@ -624,7 +625,7 @@ svcxdr_decode_deviceid4(__be32 *p, struct nfsd4_deviceid *devid)
 	devid->fsid_idx = (__force u64)(*q);
 	p += 2;
 	devid->generation = (__force u32)(*p++);
-	p++; /* NFSD does not use the remaining octets */
+	devid->dev_idx = (__force u32)(*p++);
 	return p;
 }
 
-- 
2.47.3