Re: [PATCH v2 00/10] mirror: allow switching from background to active mode

[Peter Krempa]

On Mon, Mar 04, 2024 at 11:48:54 +0100, Kevin Wolf wrote:
> Am 28.02.2024 um 19:07 hat Vladimir Sementsov-Ogievskiy geschrieben:
> > On 03.11.23 18:56, Markus Armbruster wrote:
> > > Kevin Wolf<kwolf@redhat.com>  writes:

[...]

> > > Is the job abstraction a failure?
> > > 
> > > We have
> > > 
> > >      block-job- command      since   job- command    since
> > >      -----------------------------------------------------
> > >      block-job-set-speed     1.1
> > >      block-job-cancel        1.1     job-cancel      3.0
> > >      block-job-pause         1.3     job-pause       3.0
> > >      block-job-resume        1.3     job-resume      3.0
> > >      block-job-complete      1.3     job-complete    3.0
> > >      block-job-dismiss       2.12    job-dismiss     3.0
> > >      block-job-finalize      2.12    job-finalize    3.0
> > >      block-job-change        8.2
> > >      query-block-jobs        1.1     query-jobs

[...]

> I consider these strictly optional. We don't really have strong reasons
> to deprecate these commands (they are just thin wrappers), and I think
> libvirt still uses block-job-* in some places.

Libvirt uses 'block-job-cancel' because it has different semantics from
'job-cancel' which libvirt documented as the behaviour of the API that
uses it. (Semantics regarding the expectation of what is written to the
destination node at the point when the job is cancelled).

Libvirt also uses 'block-job-set-speed' and 'query-block-jobs' but those
can be replaced easily and looking at the above table even without any
feature checks.

Thus the plan to deprecate at least 'block-job-cancel' will not work
unless the semantics are ported into 'job-cancel'.