Re: [Qemu-devel] [PATCH 0/2] Two small fixes to the streaming test case.

[Kevin Wolf <kwolf@redhat.com>]

Am 06.06.2012 14:15, schrieb Paolo Bonzini:
> 
>> A real patch series is preferable, having the patches as part of your
>> signature makes quoting them a bit harder with Thunderbird...
> 
> Oops.  Unintended, sorry.
> 
>>> From 644fda4d6da1a5babfc8884f255d87ebaf847616 Mon Sep 17 00:00:00 2001
>>> From: Paolo Bonzini <pbonzini@redhat.com>
>>> Date: Wed, 23 May 2012 13:07:56 +0200
>>> Subject: [PATCH 1/2] qemu-iotests: fill streaming test image with data
>>>
>>> This avoids that the job completes too fast when the file system
>>> reports the hole to QEMU (via FIEMAP or SEEK_HOLE).
>>>
>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>
>> Does this really fix the cause or just a symptom? The commit message
>> sounds like a race and now we happen to win it again. But maybe it's
>> just a bad wording that gives the impression.
> 
> No, unfortunately that's exactly the case.  The whole TestStreamStop
> test case is racy.
> 
> If the job completes before we can cancel it, it fails.  If we remove
> the sleep the job will be canceled before it has even started, and the
> test succeeds but I'm not sure it is testing anything worthwhile.
> 
> But if the image is left sparse, then the job has really nothing to do
> except reading one L2-table.  You're pretty much guaranteed to complete
> the job too soon, and the test fails.

Ah, you're talking about the cases where we cancel, this wasn't quite
clear and so I looked at the wrong tests. Thanks for the explanations,
the patches make sense to me now.

Can you resend a v2 as an actual patch series and use that opportunity
to make the commit messages a bit more detailed?

Kevin