Re: [Qemu-block] [Qemu-devel] [PATCH v2 21/40] job: Convert block_job_cancel_async() to Job

[Kevin Wolf]

Am 24.05.2018 um 01:18 hat John Snow geschrieben:
> > diff --git a/include/qemu/job.h b/include/qemu/job.h
> > index 3e817beee9..2648c74281 100644
> > --- a/include/qemu/job.h
> > +++ b/include/qemu/job.h
> > @@ -97,6 +97,12 @@ typedef struct Job {
> >       */
> >      bool cancelled;
> >  
> > +    /**
> > +     * Set to true if the job should abort immediately without waiting
> > +     * for data to be in sync.
> > +     */
> > +    bool force_cancel;
> > +
> 
> Does this comment need an update now, though?
> 
> Actually, in terms of "new jobs" API, it'd be really nice if cancel
> *always meant cancel*.
> 
> I think "cancel" should never be used to mean "successful completion,
> but different from the one we'd get if we used job_complete."
> 
> i.e., either we need a job setting:
> 
> job-set completion-mode=[pivot|no-pivot]
> 
> or optional parameters to pass to job-complete:
> 
> job-complete mode=[understood-by-job-type]
> 
> or some other mechanism that accomplishes the same type of behavior. It
> would be nice if it did not have to be determined at job creation time
> but instead could be determined later.

I agree. We already made sure that job-cancel really means cancel on the
QAPI level, so we're free to do that. We just need to keep supporting
block-job-cancel with the old semantics, so what I have is the easy
conversion. We can change the internal implementation when we actually
implement the selection of a completion mode.

Kevin