ceph: handle kzalloc() failure

Signed-off-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/mds_client.c

@@ -2631,6 +2631,9 @@ int ceph_mdsc_init(struct ceph_mds_client *mdsc, struct ceph_client *client)
 	mdsc->client = client;
 	mutex_init(&mdsc->mutex);
 	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
+	if (mdsc->mdsmap == NULL)
+		return -ENOMEM;
+
 	init_completion(&mdsc->safe_umount_waiters);
 	init_completion(&mdsc->session_close_waiters);
 	INIT_LIST_HEAD(&mdsc->waiting_for_map);
@@ -2656,6 +2659,7 @@ int ceph_mdsc_init(struct ceph_mds_client *mdsc, struct ceph_client *client)
 	init_waitqueue_head(&mdsc->cap_flushing_wq);
 	spin_lock_init(&mdsc->dentry_lru_lock);
 	INIT_LIST_HEAD(&mdsc->dentry_lru);
+
 	return 0;
 }