Re: [PATCH for-6.1? v2 6/7] mirror: Check job_is_cancelled() earlier

[Max Reitz]

On 27.07.21 15:13, Vladimir Sementsov-Ogievskiy wrote:
> 26.07.2021 17:46, 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.
> >
> > A job being force-cancelled should be treated the same as the job having
> > failed, so put the check in the same place where we check `s->ret < 0`.
> >
> > Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462
> > Signed-off-by: Max Reitz <mreitz@redhat.com>
> > ---
> >   block/mirror.c | 7 +------
> >   1 file changed, 1 insertion(+), 6 deletions(-)
> >
> > diff --git a/block/mirror.c b/block/mirror.c
> > index 72e02fa34e..46d1a1e5a2 100644
> > --- a/block/mirror.c
> > +++ b/block/mirror.c
> > @@ -993,7 +993,7 @@ static int coroutine_fn mirror_run(Job *job, 
> > Error **errp)
> >               mirror_wait_for_any_operation(s, true);
> >           }
> >   -        if (s->ret < 0) {
> > +        if (s->ret < 0 || job_is_cancelled(&s->common.job)) {
> >               ret = s->ret;
> >               goto immediate_exit;
> >           }
> > @@ -1078,8 +1078,6 @@ static int coroutine_fn mirror_run(Job *job, 
> > Error **errp)
> >               break;
> >           }
> >   -        ret = 0;
> > -
>
> That's just a cleanup, that statement is useless pre-patch, yes?

I think it was intended for if we left this loop via the 
job_is_cancelled() condition below.  Since it’s removed, this statement 
seems meaningless, so I removed it along with the `break`.

Max

> >           if (job_is_ready(&s->common.job) && !should_complete) {
> >               delay_ns = (s->in_flight == 0 &&
> >                           cnt == 0 ? BLOCK_JOB_SLICE_TIME : 0);
> > @@ -1087,9 +1085,6 @@ 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);
> >       }
>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>