Re: [Qemu-devel] [PATCH v2 17/40] job: Move BlockJobCreateFlags to Job

[Kevin Wolf]

Am 24.05.2018 um 00:24 hat John Snow geschrieben:
> 
> 
> On 05/18/2018 09:20 AM, Kevin Wolf wrote:
> > +    job->auto_finalize = !(flags & JOB_MANUAL_FINALIZE);
> > +    job->auto_dismiss  = !(flags & JOB_MANUAL_DISMISS);
> 
> Job API might be a good chance to say "No, this is the default behavior
> for this API."
> 
> I don't know how possible this is, but could we remove these behavior
> flags for jobs (but keep them for block jobs), and then any legacy block
> job creation interfaces we have can enable/disable them as the user
> requested,
> 
> and the block job layer itself has hooks that persuade the core job
> layer to automatically transition without user input, if appropriate.
> 
> (Unless that happens later?)

That's really a question for job-create, which we don't have yet. I'm
not sure whether job-create would expose those options, and if so, what
the defaults would be.

I think auto-dismiss=false is a good default because the reason for
having a manual job-dismiss is shared by all jobs (you want to be able
to query the job result after it finished).

auto-finalize is different. We introduced it to avoid surprise graph
changes, but this implies that every job changes the block graph when it
completes. This is obviously not true for non-block jobs. They might
still commonly change something else that shouldn't be done as a
surprise, but I am working right now on at least a single job type that
doesn't do anything like that on completion (blockdev-create).

For now, I made it unconditionally auto-finalize=true and
auto-dismiss=false without offering the options in QMP, but that's open
for discussion.

Kevin