Re: [Qemu-block] [Qemu-devel] [PATCH v4 23/23] qemu-io: Relax 'alloc' now that block-status doesn't assert

[Eric Blake]

On 10/02/2017 04:27 PM, John Snow wrote:
> 
> 
> On 09/13/2017 12:03 PM, Eric Blake wrote:
>> Previously, the alloc command required that input parameters be
>> sector-aligned and clamped to 32 bits, because the underlying
>> bdrv_is_allocated used a 32-bit parameter and asserted aligned
>> inputs.  But now that we have fixed block status to report a
>> 64-bit bytes value, and to properly round requests on behalf of
>> guests, we can pass any values, and can use qemu-io to add
>> coverage that our rounding is correct regardless of the guest
>> alignment constraints.
>>
>> Update iotest 177 to intentionally probe block status at
>> unaligned boundaries as well as with a bytes value that does not
>> map to 32-bit sectors, which also required tweaking the image
>> prep to leave an unallocated portion to the image under test.
>>
>> Signed-off-by: Eric Blake <address@hidden>
>>

>>  echo
>> +echo "== block status smaller than alignment =="
>> +limits=align=4k
>> +$QEMU_IO -c "open -o $options,$limits blkdebug::$TEST_IMG" \
>> +     -c "alloc 1 1" -c "alloc 0x6dffff0 1000" -c "alloc 127m 5P" \
>> +     -c map | _filter_qemu_io
>> +

> 
> aaand I'll hold off on this one until the respin so I don't have to
> review the test twice.

Fair enough; thanks for the reviews.

By the way, it's operations like the above additions where you can step
through bdrv_co_block_status in gdb to see all the rounding/alignment
steps in action, so I do feel pretty confident that my changes in 21/23
were fairly well covered.

> 
> I'll say I'm done for v4 for now :)

I'll try to get v5 posted in the next day or two.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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