From: Dmitry Fomichev dmitry.fomichev@wdc.com
commit d1fef41465f0e8cae0693fb184caa6bfafb6cd16 upstream.
This patch fixes a problem in dm-kcopyd that may leave jobs in complete queue indefinitely in the event of backing storage failure.
This behavior has been observed while running 100% write file fio workload against an XFS volume created on top of a dm-zoned target device. If the underlying storage of dm-zoned goes to offline state under I/O, kcopyd sometimes never issues the end copy callback and dm-zoned reclaim work hangs indefinitely waiting for that completion.
This behavior was traced down to the error handling code in process_jobs() function that places the failed job to complete_jobs queue, but doesn't wake up the job handler. In case of backing device failure, all outstanding jobs may end up going to complete_jobs queue via this code path and then stay there forever because there are no more successful I/O jobs to wake up the job handler.
This patch adds a wake() call to always wake up kcopyd job wait queue for all I/O jobs that fail before dm_io() gets called for that job.
The patch also sets the write error status in all sub jobs that are failed because their master job has failed.
Fixes: b73c67c2cbb00 ("dm kcopyd: add sequential write feature") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Fomichev dmitry.fomichev@wdc.com Reviewed-by: Damien Le Moal damien.lemoal@wdc.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/dm-kcopyd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/md/dm-kcopyd.c +++ b/drivers/md/dm-kcopyd.c @@ -548,8 +548,10 @@ static int run_io_job(struct kcopyd_job * no point in continuing. */ if (test_bit(DM_KCOPYD_WRITE_SEQ, &job->flags) && - job->master_job->write_err) + job->master_job->write_err) { + job->write_err = job->master_job->write_err; return -EIO; + }
io_job_start(job->kc->throttle);
@@ -601,6 +603,7 @@ static int process_jobs(struct list_head else job->read_err = 1; push(&kc->complete_jobs, job); + wake(kc); break; }