ceph: should use deactivate_locked_super() on failure exits

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 110857b..9307bbe 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -952,8 +952,7 @@
 
 out_splat:
 	ceph_mdsc_close_sessions(&client->mdsc);
-	up_write(&sb->s_umount);
-	deactivate_super(sb);
+	deactivate_locked_super(sb);
 	goto out_final;
 
 out: