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@xxxxxxxxxxxxxxx
Signed-off-by: Dmitry Fomichev <dmitry.fomichev@xxxxxxx>
---
drivers/md/dm-kcopyd.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index df2011de7be2..1bbe4a34ef4c 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -566,8 +566,10 @@ static int run_io_job(struct kcopyd_job *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);
@@ -619,6 +621,7 @@ static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc,
else
job->read_err = 1;
push(&kc->complete_jobs, job);
+ wake(kc);
break;
}
--
2.21.0
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