Re: [Qemu-devel] [PATCH v2 1/1] mirror: do not increase offset during initial zero_or_discard phase

[Denis V. Lunev]

On 02/03/2017 05:52 PM, Stefan Hajnoczi wrote:
> On Thu, Feb 02, 2017 at 05:25:15PM +0300, Denis V. Lunev wrote:
>> From: Anton Nefedov <address@hidden>
>>
>> If explicit zeroing out before mirroring is required for the target image,
>> it moves the block job offset counter to EOF, then offset and len counters
>> count the image size twice. There is no harm but stats are confusing,
>> specifically the progress of the operation is always reported as 99% by
>> management tools.
>>
>> The patch skips offset increase for the first "technical" pass over the
>> image. This should not cause any further harm.
>>
>> Signed-off-by: Anton Nefedov <address@hidden>
>> Signed-off-by: Denis V. Lunev <address@hidden>
>> CC: Jeff Cody <address@hidden>
>> CC: Kevin Wolf <address@hidden>
>> CC: Max Reitz <address@hidden>
>> CC: Eric Blake <address@hidden>
>> ---
>> Changes from v1:
>> - changed the approach - we do not allow to increase the offset rather then
>>   to move it back
>> - description rewritten
>> - kludges to tests are removed as not actually needed with this approach
>>
>>  block/mirror.c | 9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
> Another option is to put the flag in MirrorOp instead of MirrorBlockJob.
> That reduces the scope of the variable, but this is okay too:
>
> Reviewed-by: Stefan Hajnoczi <address@hidden>
In this case we will have to pass argument through several
layers on request creation path. Current approach is better.

Thank you for the review :)

Den