From: Dongsheng Yang dongsheng.yang@easystack.cn
[ Upstream commit 25e6be21230d3208d687dad90b6e43419013c351 ]
There is a warning message in my test with below steps:
# rbd bench --io-type write --io-size 4K --io-threads 1 --io-pattern rand test & # sleep 5 # pkill -9 rbd # rbd map test & # sleep 5 # pkill rbd
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.
1. do_rbd_add() 2. lock_dwork rbd_add_acquire_lock() - queue_delayed_work() lock_dwork queued - wait_for_completion_killable_timeout() <-- kill happen rbd_dev_image_unlock() <-- UNLOCKED now, nothing to do. rbd_dev_device_release() rbd_dev_image_release() - ... lock successed here - cancel_delayed_work_sync(&rbd_dev->lock_dwork)
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/rbd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index c8fb886aebd4e..e6369b9f33873 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -6632,10 +6632,13 @@ static int rbd_add_acquire_lock(struct rbd_device *rbd_dev) queue_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0); ret = wait_for_completion_killable_timeout(&rbd_dev->acquire_wait, ceph_timeout_jiffies(rbd_dev->opts->lock_timeout)); - if (ret > 0) + if (ret > 0) { ret = rbd_dev->acquire_err; - else if (!ret) - ret = -ETIMEDOUT; + } else { + cancel_delayed_work_sync(&rbd_dev->lock_dwork); + if (!ret) + ret = -ETIMEDOUT; + }
if (ret) { rbd_warn(rbd_dev, "failed to acquire exclusive lock: %ld", ret);