RBD_WATCH_STATE_UNREGISTERED
rbd_assert(rbd_dev->watch_state == RBD_WATCH_STATE_UNREGISTERED);
rbd_dev->watch_state = RBD_WATCH_STATE_UNREGISTERED;
WARN_ON(rbd_dev->watch_state != RBD_WATCH_STATE_UNREGISTERED);
rbd_dev->watch_state = RBD_WATCH_STATE_UNREGISTERED;