NFSv4.1: Add a helper function to deal with expired stateids

In NFSv4.1 and newer, if the server decides to revoke some or all of
the protocol state, the client is required to iterate through all the
stateids that it holds and call TEST_STATEID to determine which stateids
still correspond to valid state, and then call FREE_STATEID on the
others.

Signed-off-by: Trond Myklebust <[e-mail]>
Tested-by: Oleg Drokin <[e-mail]>
Signed-off-by: Anna Schumaker <[e-mail]>

fs/nfs/nfs4proc.c

···
 }
 
 #if defined(CONFIG_NFS_V4_1)
+static int nfs41_test_and_free_expired_stateid(struct nfs_server *server,
+		nfs4_stateid *stateid,
+		struct rpc_cred *cred)
+{
+	int status;
+
+	status = nfs41_test_stateid(server, stateid, cred);
+
+	switch (status) {
+	case -NFS4ERR_EXPIRED:
+	case -NFS4ERR_ADMIN_REVOKED:
+	case -NFS4ERR_DELEG_REVOKED:
+		/* Ack the revoked state to the server */
+		nfs41_free_stateid(server, stateid, cred);
+	case -NFS4ERR_BAD_STATEID:
+		return status;
+	}
+	return NFS_OK;
+}
+
 static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 {
 	struct nfs_server *server = NFS_SERVER(state->inode);
···
 	nfs4_stateid_copy(&stateid, &delegation->stateid);
 	cred = get_rpccred(delegation->cred);
 	rcu_read_unlock();
-	status = nfs41_test_stateid(server, &stateid, cred);
+	status = nfs41_test_and_free_expired_stateid(server, &stateid, cred);
 	trace_nfs4_test_delegation_stateid(state, NULL, status);
-
-	if (status != NFS_OK) {
-		/* Free the stateid unless the server explicitly
-		 * informs us the stateid is unrecognized. */
-		if (status != -NFS4ERR_BAD_STATEID)
-			nfs41_free_stateid(server, &stateid, cred);
+	if (status != NFS_OK)
 		nfs_finish_clear_delegation_stateid(state);
-	}
 
 	put_rpccred(cred);
 }
···
 	    (test_bit(NFS_O_RDWR_STATE, &state->flags) == 0))
 		return -NFS4ERR_BAD_STATEID;
 
-	status = nfs41_test_stateid(server, stateid, cred);
+	status = nfs41_test_and_free_expired_stateid(server, stateid, cred);
 	trace_nfs4_test_open_stateid(state, NULL, status);
 	if (status != NFS_OK) {
-		/* Free the stateid unless the server explicitly
-		 * informs us the stateid is unrecognized. */
-		if (status != -NFS4ERR_BAD_STATEID)
-			nfs41_free_stateid(server, stateid, cred);
-
 		clear_bit(NFS_O_RDONLY_STATE, &state->flags);
 		clear_bit(NFS_O_WRONLY_STATE, &state->flags);
 		clear_bit(NFS_O_RDWR_STATE, &state->flags);
···
 		if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags)) {
 			struct rpc_cred *cred = lsp->ls_state->owner->so_cred;
 
-			status = nfs41_test_stateid(server,
+			status = nfs41_test_and_free_expired_stateid(server,
 					&lsp->ls_stateid,
 					cred);
 			trace_nfs4_test_lock_stateid(state, lsp, status);
 			if (status != NFS_OK) {
-				/* Free the stateid unless the server
-				 * informs us the stateid is unrecognized. */
-				if (status != -NFS4ERR_BAD_STATEID)
-					nfs41_free_stateid(server,
-							&lsp->ls_stateid,
-							cred);
 				clear_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags);
 				ret = status;
 			}