Re: [Qemu-devel] [PATCH v2] qemu-iotests: prefill some data to test image

[Fam Zheng <famz@redhat.com>]

On Wed, 10/30 12:15, Kevin Wolf wrote:
> Am 30.10.2013 um 10:42 hat Fam Zheng geschrieben:
> > Case 030 occasionally fails because of block job compltes too fast to be
> > captured by script, and 'unexpected qmp event' of job completion causes
> > the test failure.
> > 
> > Simply fill in some data to the test image to make this false alarm less
> > likely to happen.
> > 
> > (For other benefits to prefill data to test image, see also commit
> > ab68cdfaa).
> > 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > 
> > ---
> > v2: subsequent to "qemu-iotests: fix 030 for faster machines".
> > 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> 
> Did you try using blkdebug to make it deterministic instead of just
> making failure less likely?

Yes. blkdebug relies on actual IO, but using images with no data doesn't
trigger any IO and just completes. Prefilling is the prerequisite to use that.
This alone already works very well for me, but blkdebug is good to have, too.

Suspending before starting the block job is obviously the way to do, but
resuming before cancel_and_wait is not deterministic, either, in the same way.
We'll need to add cancel_and_resume_and_wait().

Do you like me to respin or use a follow up patch?

Fam