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25e6be2123
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: 637cd06053 ("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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.