nfsd: allow nfsd to advertise multiple layout types

If the underlying filesystem supports multiple layout types, then there
is little reason not to advertise that fact to clients and let them
choose what type to use.

Turn the ex_layout_type field into a bitfield. For each supported
layout type, we set a bit in that field. When the client requests a
layout, ensure that the bit for that layout type is set. When the
client requests attributes, send back a list of supported types.

Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Reviewed-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 14 insertions, 16 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 84ef94794496..0aa0236a1429 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2162,22 +2162,20 @@ nfsd4_encode_aclname(struct xdr_stream *xdr, struct svc_rqst *rqstp,
 }
 
 static inline __be32
-nfsd4_encode_layout_type(struct xdr_stream *xdr, enum pnfs_layouttype layout_type)
+nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
 {
-	__be32 *p;
+	__be32		*p;
+	unsigned long	i = hweight_long(layout_types);
 
-	if (layout_type) {
-		p = xdr_reserve_space(xdr, 8);
-		if (!p)
-			return nfserr_resource;
-		*p++ = cpu_to_be32(1);
-		*p++ = cpu_to_be32(layout_type);
-	} else {
-		p = xdr_reserve_space(xdr, 4);
-		if (!p)
-			return nfserr_resource;
-		*p++ = cpu_to_be32(0);
-	}
+	p = xdr_reserve_space(xdr, 4 + 4 * i);
+	if (!p)
+		return nfserr_resource;
+
+	*p++ = cpu_to_be32(i);
+
+	for (i = LAYOUT_NFSV4_1_FILES; i < LAYOUT_TYPE_MAX; ++i)
+		if (layout_types & (1 << i))
+			*p++ = cpu_to_be32(i);
 
 	return 0;
 }
@@ -2752,13 +2750,13 @@ out_acl:
 	}
 #ifdef CONFIG_NFSD_PNFS
 	if (bmval1 & FATTR4_WORD1_FS_LAYOUT_TYPES) {
-		status = nfsd4_encode_layout_type(xdr, exp->ex_layout_type);
+		status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
 		if (status)
 			goto out;
 	}
 
 	if (bmval2 & FATTR4_WORD2_LAYOUT_TYPES) {
-		status = nfsd4_encode_layout_type(xdr, exp->ex_layout_type);
+		status = nfsd4_encode_layout_types(xdr, exp->ex_layout_types);
 		if (status)
 			goto out;
 	}