Re: [Qemu-devel] [PATCH v5 4/6] qemu-io: Allow unaligned access by default

[Eric Blake <eblake@redhat.com>]

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On 05/12/2016 09:50 AM, Eric Blake wrote:
>> This breaks qemu-iotests 136 for raw. It's pretty obvious that this is a
>> test case problem (uses unaligned requests to test error accounting), so
>> I'm not dropping the patch, but please do send a follow-up.
> 
> ...which explains why I missed this failure with ./check -raw.  Will
> fix, and maybe I should have grepped a bit harder, since it is fairly
> obvious:
> 
> tests/qemu-iotests/136:        # Two types of invalid operations:
> unaligned length and unaligned offset
> 
> I will also check if this needs updating:
> 
> tests/qemu-iotests/109:    # qemu-img compare can't handle unaligned
> file sizes

Turns out the comment was stale, even before my recent patches, but I
didn't bother bisecting to find when qemu-img learned to handle
unaligned raw images.  But see my comments in my other mail on the patch
for this file: 'qemu-img compare' doesn't necessarily give the nicest of
error messages for unaligned files

> 
> as both of those tests run under -raw but not -qcow2
> 
>>
>> Maybe negative length and offset work as a replacement.

Sadly, no, because cvtnum() doesn't like things larger than INT64_MAX,
so you can't pass in a negative number.  I added a new '-i' flag
instead; series now available for review.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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