Re: [PATCH 1/1] bcache: release the lock before stopping the writeback thread

[Shan Hai]

Hi Coly,


On 2018年08月22日 15:29, Coly Li wrote:

Hi Shan,

On 2018/8/22 3:00 PM, Shan Hai wrote:

The writeback thread would exit with a lock held when the cache device is
detached via sysfs interface, fix it by releasing the held lock before exiting
the thread.

I will change "the thread" to "the while-loop" when I apply this patch.

That's fine, your change is better.

Signed-off-by: Shan Hai <shan....@oracle.com>

Nice catch!

This one should go to stable trees since 4.17 as well. I will CC stable
maintainers when I submit this one for 4.19.

OK, thanks for the quick response.

Regards
Shan Hai

Thank you for the fix.

Coly Li

---
  drivers/md/bcache/writeback.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 481d4cf..adc583f 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -679,8 +679,10 @@ static int bch_writeback_thread(void *arg)
                         * data on cache. BCACHE_DEV_DETACHING flag is set in
                         * bch_cached_dev_detach().
                         */
-                       if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
+                       if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) {
+                               up_write(&dc->writeback_lock);
                                break;
+                       }
                }

up_write(&dc->writeback_lock);