NFSv4: Check the return value of update_open_stateid()

Ensure that we always check the return value of update_open_stateid()
so that we can retry if the update of local state failed. This fixes
infinite looping on state recovery.

Fixes: e23008ec ("NFSv4 reduce attribute requests for open reclaim")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v3.7+

fs/nfs/nfs4proc.c

@@ -1915,8 +1915,9 @@ _nfs4_opendata_reclaim_to_nfs4_state(struct nfs4_opendata *data)
 	if (data->o_res.delegation_type != 0)
 		nfs4_opendata_check_deleg(data, state);
 update:
-	update_open_stateid(state, &data->o_res.stateid, NULL,
-			    data->o_arg.fmode);
+	if (!update_open_stateid(state, &data->o_res.stateid,
+				NULL, data->o_arg.fmode))
+		return ERR_PTR(-EAGAIN);
 	refcount_inc(&state->count);
 
 	return state;
@@ -1981,8 +1982,11 @@ _nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
 
 	if (data->o_res.delegation_type != 0)
 		nfs4_opendata_check_deleg(data, state);
-	update_open_stateid(state, &data->o_res.stateid, NULL,
-			data->o_arg.fmode);
+	if (!update_open_stateid(state, &data->o_res.stateid,
+				NULL, data->o_arg.fmode)) {
+		nfs4_put_open_state(state);
+		state = ERR_PTR(-EAGAIN);
+	}
 out:
 	nfs_release_seqid(data->o_arg.seqid);
 	return state;