The reason is that the rbd_add_acquire_lock() is interruptable,
that means, when we kill the waiting on ->acquire_wait, the lock_dwork
could be still running.
Then when we reach the rbd_dev_free(), WARN_ON is triggered because
lock_state is not RBD_LOCK_STATE_UNLOCKED.
To fix it, this commit make sure the lock_dwork was finished before
calling rbd_dev_image_unlock().
On the other hand, this would not happend in do_rbd_remove(), because
after rbd mapped, lock_dwork will only be queued for IO request, and
request will continue unless lock_dwork finished. when we call
rbd_dev_image_unlock() in do_rbd_remove(), all requests are done.
That means, lock_state should not be locked again after
rbd_dev_image_unlock().
[ Cancel lock_dwork in rbd_add_acquire_lock(), only if the wait is
interrupted. ]
Fixes: 637cd060537d ("rbd: new exclusive lock wait/wake code") Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>