NFSv4: Ensure we do not reuse open owner names

The NFSv4 spec is ambiguous about whether or not it is permissible
to reuse open owner names, so play it safe. This patch adds a timestamp
to the state_owner structure, and combines that with the IDA based
uniquifier.
Fixes a regression whereby the Linux server returns NFS4ERR_BAD_SEQID.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index c74fdb1..77fc5f9 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -74,7 +74,7 @@
 /* lock,open owner id:
  * we currently use size 2 (u64) out of (NFS4_OPAQUE_LIMIT  >> 2)
  */
-#define open_owner_id_maxsz	(1 + 1 + 4)
+#define open_owner_id_maxsz	(1 + 2 + 1 + 1 + 2)
 #define lock_owner_id_maxsz	(1 + 1 + 4)
 #define decode_lockowner_maxsz	(1 + XDR_QUADLEN(IDMAP_NAMESZ))
 #define compound_encode_hdr_maxsz	(3 + (NFS4_MAXTAGLEN >> 2))
@@ -1340,12 +1340,13 @@
  */
 	encode_nfs4_seqid(xdr, arg->seqid);
 	encode_share_access(xdr, arg->fmode);
-	p = reserve_space(xdr, 32);
+	p = reserve_space(xdr, 36);
 	p = xdr_encode_hyper(p, arg->clientid);
-	*p++ = cpu_to_be32(20);
+	*p++ = cpu_to_be32(24);
 	p = xdr_encode_opaque_fixed(p, "open id:", 8);
 	*p++ = cpu_to_be32(arg->server->s_dev);
-	xdr_encode_hyper(p, arg->id);
+	*p++ = cpu_to_be32(arg->id.uniquifier);
+	xdr_encode_hyper(p, arg->id.create_time);
 }
 
 static inline void encode_createmode(struct xdr_stream *xdr, const struct nfs_openargs *arg)