NFSv4.1: Allow test_stateid to handle session errors without waiting

If the server crashes while we're testing stateids for validity, then
we want to initiate session recovery. Usually, we will be calling from
a state manager thread, though, so we don't really want to wait.

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

fs/nfs/nfs4proc.c

···
 	return -res.status;
 }
 
+static void nfs4_handle_delay_or_session_error(struct nfs_server *server,
+		int err, struct nfs4_exception *exception)
+{
+	exception->retry = 0;
+	switch(err) {
+	case -NFS4ERR_DELAY:
+		nfs4_handle_exception(server, err, exception);
+		break;
+	case -NFS4ERR_BADSESSION:
+	case -NFS4ERR_BADSLOT:
+	case -NFS4ERR_BAD_HIGH_SLOT:
+	case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
+	case -NFS4ERR_DEADSESSION:
+		nfs4_do_handle_exception(server, err, exception);
+	}
+}
+
 /**
  * nfs41_test_stateid - perform a TEST_STATEID operation
  *
···
 	int err;
 	do {
 		err = _nfs41_test_stateid(server, stateid, cred);
-		if (err != -NFS4ERR_DELAY)
-			break;
-		nfs4_handle_exception(server, err, &exception);
+		nfs4_handle_delay_or_session_error(server, err, &exception);
 	} while (exception.retry);
 	return err;
 }