ceph: throw a warning if we destroy session with mutex still locked

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/mds_client.c

@@ -659,6 +659,7 @@ void ceph_put_mds_session(struct ceph_mds_session *s)
 	if (refcount_dec_and_test(&s->s_ref)) {
 		if (s->s_auth.authorizer)
 			ceph_auth_destroy_authorizer(s->s_auth.authorizer);
+		WARN_ON(mutex_is_locked(&s->s_mutex));
 		xa_destroy(&s->s_delegated_inos);
 		kfree(s);
 	}