Re: [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct

[Vladimir Sementsov-Ogievskiy]

On 7/19/22 16:07, Emanuele Giuseppe Esposito wrote:
> Am 11/07/2022 um 16:51 schrieb Vladimir Sementsov-Ogievskiy:
> > On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> > > iostatus is the only field (together with .job) that needs
> > > protection using the job mutex.
> > >
> > > It is set in the main loop (GLOBAL_STATE functions) but read
> > > in I/O code (block_job_error_action).
> > >
> > > In order to protect it, change block_job_iostatus_set_err
> > > to block_job_iostatus_set_err_locked(), always called under
> > > job lock.
> > >
> > > Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> >
> > Seems, that (and previous) patch should go before 15.
>
> Why?

As I understand, before patch 15 everything was protected by aio-context lock. 
After patch 15, this becomes a bug, which we fix now. If we do it before patch 
15, we never introduce the bug.. Or what I miss?

> > > ---
> > >    blockjob.c | 5 +++--
> > >    1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/blockjob.c b/blockjob.c
> > > index a2559b97a7..893c8ff08e 100644
> > > --- a/blockjob.c
> > > +++ b/blockjob.c
> > > @@ -367,7 +367,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error
> > > **errp)
> > >        return block_job_query_locked(job, errp);
> > >    }
> > >    -static void block_job_iostatus_set_err(BlockJob *job, int error)
> > > +/* Called with job lock held */
> > > +static void block_job_iostatus_set_err_locked(BlockJob *job, int error)
> > >    {
> > >        if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
> > >            job->iostatus = error == ENOSPC ?
> > > BLOCK_DEVICE_IO_STATUS_NOSPACE :
> > > @@ -586,8 +587,8 @@ BlockErrorAction block_job_error_action(BlockJob
> > > *job, BlockdevOnError on_err,
> > >                     */
> > >                    job->job.user_paused = true;
> > >                }
> > > +            block_job_iostatus_set_err_locked(job, error);
> > >            }
> > > -        block_job_iostatus_set_err(job, error);
> > >        }
> > >        return action;
> > >    }


--
Best regards,
Vladimir