NFSv4: Ensure continued open and lockowner name uniqueness

In order to enable migration support, we will want to move some of the
structures that are subject to migration into the struct nfs_server.
In particular, if we are to move the state_owner and state_owner_id to
being a per-filesystem structure, then we should label the resulting
open/lock owners with a per-filesytem label to ensure global uniqueness.

This patch does so by adding the super block s_dev to the open/lock owner
name.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4proc.c

@@ -3779,6 +3779,7 @@ static int _nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock
 		goto out;
 	lsp = request->fl_u.nfs4_fl.owner;
 	arg.lock_owner.id = lsp->ls_id.id;
+	arg.lock_owner.s_dev = server->s_dev;
 	status = nfs4_call_sync(server, &msg, &arg, &res, 1);
 	switch (status) {
 		case 0:
@@ -4024,6 +4025,7 @@ static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
 	p->arg.lock_stateid = &lsp->ls_stateid;
 	p->arg.lock_owner.clientid = server->nfs_client->cl_clientid;
 	p->arg.lock_owner.id = lsp->ls_id.id;
+	p->arg.lock_owner.s_dev = server->s_dev;
 	p->res.lock_seqid = p->arg.lock_seqid;
 	p->lsp = lsp;
 	p->server = server;
@@ -4428,6 +4430,7 @@ void nfs4_release_lockowner(const struct nfs4_lock_state *lsp)
 		return;
 	args->lock_owner.clientid = server->nfs_client->cl_clientid;
 	args->lock_owner.id = lsp->ls_id.id;
+	args->lock_owner.s_dev = server->s_dev;
 	msg.rpc_argp = args;
 	rpc_call_async(server->client, &msg, 0, &nfs4_release_lockowner_ops, args);
 }

fs/nfs/nfs4xdr.c

@@ -71,8 +71,8 @@ static int nfs4_stat_to_errno(int);
 /* lock,open owner id:
  * we currently use size 2 (u64) out of (NFS4_OPAQUE_LIMIT  >> 2)
  */
-#define open_owner_id_maxsz	(1 + 4)
-#define lock_owner_id_maxsz	(1 + 4)
+#define open_owner_id_maxsz	(1 + 1 + 4)
+#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))
 #define compound_decode_hdr_maxsz	(3 + (NFS4_MAXTAGLEN >> 2))
@@ -1088,10 +1088,11 @@ static void encode_lockowner(struct xdr_stream *xdr, const struct nfs_lowner *lo
 {
 	__be32 *p;
 
-	p = reserve_space(xdr, 28);
+	p = reserve_space(xdr, 32);
 	p = xdr_encode_hyper(p, lowner->clientid);
-	*p++ = cpu_to_be32(16);
+	*p++ = cpu_to_be32(20);
 	p = xdr_encode_opaque_fixed(p, "lock id:", 8);
+	*p++ = cpu_to_be32(lowner->s_dev);
 	xdr_encode_hyper(p, lowner->id);
 }
 
@@ -1210,10 +1211,11 @@ static inline void encode_openhdr(struct xdr_stream *xdr, const struct nfs_opena
 	*p++ = cpu_to_be32(OP_OPEN);
 	*p = cpu_to_be32(arg->seqid->sequence->counter);
 	encode_share_access(xdr, arg->fmode);
-	p = reserve_space(xdr, 28);
+	p = reserve_space(xdr, 32);
 	p = xdr_encode_hyper(p, arg->clientid);
-	*p++ = cpu_to_be32(16);
+	*p++ = cpu_to_be32(20);
 	p = xdr_encode_opaque_fixed(p, "open id:", 8);
+	*p++ = cpu_to_be32(arg->server->s_dev);
 	xdr_encode_hyper(p, arg->id);
 }
 

include/linux/nfs_xdr.h

@@ -317,6 +317,7 @@ struct nfs_closeres {
 struct nfs_lowner {
 	__u64			clientid;
 	__u64			id;
+	dev_t			s_dev;
 };
 
 struct nfs_lock_args {