Re: [Qemu-devel] [Qemu-block] [PATCH v2] qapi: block-core: Clarify events emitted by 'block-job-cancel'

[Kashyap Chamarthy <kchamart@redhat.com>]

On Wed, Nov 15, 2017 at 02:15:57PM -0500, John Snow wrote:
> 
> 
> On 11/15/2017 04:09 AM, Kashyap Chamarthy wrote:
> > When you cancel an in-progress live block operation with QMP
> > `block-job-cancel`, it emits the event: BLOCK_JOB_CANCELLED.  However,
> > when `block-job-cancel` is issued after `drive-mirror` has indicated (by
> > emitting the event BLOCK_JOB_READY) that the source and destination
> > remain synchronized:

[...]

> > But this is expected behaviour, where the _COMPLETED event indicates
> > that synchronization has successfully ended (and the destination has a
> > point-in-time copy, which is at the time of cancel).
> > 
> > So add a small note to this effect.  (Thanks: Max Reitz for reminding
> > me of this on IRC.)
> > 
> 
> I suppose this difference probably isn't covered in what was the
> bitmaps.md doc file (we don't bother covering mirror there, only
> backup); 

Your supposition is correct: Looking at the now-renamed
'bitmaps.rst'[1], it isn't covered there.

> is it covered sufficiently in live-block-operations.rst ?

I looked in there[2] too.  Short answer: no.  Long: In the "Live disk
synchronization — drive-mirror and blockdev-mirror" section, I simply
seemed to declare: 

    "Issuing the command ``block-job-cancel`` after it emits the event
    ``BLOCK_JOB_CANCELLED``"

As if that's the *only* event it emits, which is clearly not the case.
So while at it, wonder if should I also update it
('live-block-operations.rst') too.

[1] https://git.qemu.org/?p=qemu.git;a=blob;f=docs/interop/bitmaps.rst
[2] https://git.qemu.org/?p=qemu.git;a=blob;f=docs/interop/live-block-operations.rst#l513 

-- 
/kashyap