Commit d046bb9e authored Jan 08, 2018 by Tang Junhui Committed by Greg Kroah-Hartman Apr 13, 2018

bcache: stop writeback thread after detaching




[ Upstream commit 8d29c4426b9f8afaccf28de414fde8a722b35fdf ]

Currently, when a cached device detaching from cache, writeback thread is
not stopped, and writeback_rate_update work is not canceled. For example,
after the following command:
echo 1 >/sys/block/sdb/bcache/detach
you can still see the writeback thread. Then you attach the device to the
cache again, bcache will create another writeback thread, for example,
after below command:
echo  ba0fb5cd-658a-4533-9806-6ce166d883b9 > /sys/block/sdb/bcache/attach
then you will see 2 writeback threads.
This patch stops writeback thread and cancels writeback_rate_update work
when cached device detaching from cache.

Compare with patch v1, this v2 patch moves code down into the register
lock for safety in case of any future changes as Coly and Mike suggested.

[edit by mlyle: commit log spelling/formatting]

Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 9622668c

drivers/md/bcache/super.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -892,6 +892,12 @@ static void cached_dev_detach_finish(struct work_struct *w)

		mutex_lock(&bch_register_lock);

		cancel_delayed_work_sync(&dc->writeback_rate_update);
		if (!IS_ERR_OR_NULL(dc->writeback_thread)) {
		kthread_stop(dc->writeback_thread);
		dc->writeback_thread = NULL;
		}

		memset(&dc->sb.set_uuid, 0, 16);
		SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);