Re: [PATCH for-6.2 v3 05/12] job: @force parameter for job_cancel_sync{, _all}()

[Max Reitz <mreitz@redhat.com>]

On 06.08.21 21:39, Eric Blake wrote:
> On Fri, Aug 06, 2021 at 11:38:52AM +0200, Max Reitz wrote:
>> Callers should be able to specify whether they want job_cancel_sync() to
>> force-cancel the job or not.
>>
>> In fact, almost all invocations do not care about consistency of the
>> result and just want the job to terminate as soon as possible, so they
>> should pass force=true.  The replication block driver is the exception.
>>
>> This changes some iotest outputs, because quitting qemu while a mirror
>> job is active will now lead to it being cancelled instead of completed,
>> which is what we want.  (Cancelling a READY mirror job with force=false
>> may take an indefinite amount of time, which we do not want when
>> quitting.  If users want consistent results, they must have all jobs be
>> done before they quit qemu.)
> Feels somewhat like a bug fix, but I also understand why you'd prefer
> to delay this to 6.2 (it is not a fresh regression, but a longstanding
> issue).

It is, hence the “Buglink” tag below.  However, only all of this series 
together really fixes that bug (or at least patches 5+7+9 together), 
just taking one wouldn’t help much.  And together, it’s just too much 
for 6.2 at this point.

>> Buglink: https://gitlab.com/qemu-project/qemu/-/issues/462
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
>> ---
>> +++ b/job.c
>> @@ -982,12 +982,24 @@ static void job_cancel_err(Job *job, Error **errp)
>>       job_cancel(job, false);
>>   }
>>   
>> -int job_cancel_sync(Job *job)
>> +/**
>> + * Same as job_cancel_err(), but force-cancel.
>> + */
>> +static void job_force_cancel_err(Job *job, Error **errp)
>>   {
>> -    return job_finish_sync(job, &job_cancel_err, NULL);
>> +    job_cancel(job, true);
>> +}
> In isolation, it looks odd that errp is passed but not used.  But
> looking further, it's because this is a callback that must have a
> given signature, so it's okay.
>
> Reviewed-by: Eric Blake <eblake@redhat.com>
>