From ef60904109f4b90a2dea0919fed297c6c3fc6c25 Mon Sep 17 00:00:00 2001 From: Tang Junhui Date: Mon, 8 Jan 2018 12:21:19 -0800 Subject: [PATCH] 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 Reviewed-by: Michael Lyle Signed-off-by: Michael Lyle Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/super.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 9417170f180a..5d0430777dda 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -893,6 +893,12 @@ 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); -- 2.20.1