| Message ID | 20210806093859.706464-10-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | mirror: Handle errors after READY cancel | expand |
On Fri, Aug 06, 2021 at 11:38:56AM +0200, Max Reitz wrote: > We must check whether the job is force-cancelled early in our main loop, > most importantly before any `continue` statement. For example, we used > to have `continue`s before our current checking location that are > triggered by `mirror_flush()` failing. So, if `mirror_flush()` kept > failing, force-cancelling the job would not terminate it. > > Jobs can be cancelled while they yield, and once they are > (force-cancelled), they should not generate new I/O requests. > Therefore, we should put the check after the last yield before > mirror_iteration() is invoked. > > Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462 > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > block/mirror.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) Reviewed-by: Eric Blake <eblake@redhat.com>
06.08.2021 12:38, Max Reitz wrote: > We must check whether the job is force-cancelled early in our main loop, > most importantly before any `continue` statement. For example, we used > to have `continue`s before our current checking location that are > triggered by `mirror_flush()` failing. So, if `mirror_flush()` kept > failing, force-cancelling the job would not terminate it. > > Jobs can be cancelled while they yield, and once they are > (force-cancelled), they should not generate new I/O requests. > Therefore, we should put the check after the last yield before > mirror_iteration() is invoked. > > Buglink:https://gitlab.com/qemu-project/qemu/-/issues/462 > Signed-off-by: Max Reitz<mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
diff --git a/block/mirror.c b/block/mirror.c index 024fa2dcea..bf1d50ff1c 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1000,6 +1000,11 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) job_pause_point(&s->common.job); + if (job_is_cancelled(&s->common.job)) { + ret = 0; + goto immediate_exit; + } + cnt = bdrv_get_dirty_count(s->dirty_bitmap); /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is * the number of bytes currently being processed; together those are @@ -1078,8 +1083,6 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) break; } - ret = 0; - if (job_is_ready(&s->common.job) && !should_complete) { delay_ns = (s->in_flight == 0 && cnt == 0 ? BLOCK_JOB_SLICE_TIME : 0); @@ -1087,9 +1090,6 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) trace_mirror_before_sleep(s, cnt, job_is_ready(&s->common.job), delay_ns); job_sleep_ns(&s->common.job, delay_ns); - if (job_is_cancelled(&s->common.job)) { - break; - } s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); }
We must check whether the job is force-cancelled early in our main loop, most importantly before any `continue` statement. For example, we used to have `continue`s before our current checking location that are triggered by `mirror_flush()` failing. So, if `mirror_flush()` kept failing, force-cancelling the job would not terminate it. Jobs can be cancelled while they yield, and once they are (force-cancelled), they should not generate new I/O requests. Therefore, we should put the check after the last yield before mirror_iteration() is invoked. Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462 Signed-off-by: Max Reitz <mreitz@redhat.com> --- block/mirror.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)