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Date: Thu, 27 Aug 2015 10:45:16 +0300
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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Subject: Re: [Qemu-devel] [PATCH 6/8] qcow2: add autoclear bit for dirty
	bitmaps
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, Vladimir Sementsov-Ogievskiy <vsementsov@parallels.com>, stefanha@redhat.com, den@openvz.org, pbonzini@redhat.com, jsnow@redhat.com

On 09.06.2015 18:50, Stefan Hajnoczi wrote:
> On Mon, Jun 08, 2015 at 06:21:24PM +0300, Vladimir Sementsov-Ogievskiy wrote:
>> diff --git a/block/qcow2.c b/block/qcow2.c
>> index 406e55d..f85a55a 100644
>> --- a/block/qcow2.c
>> +++ b/block/qcow2.c
>> @@ -182,6 +182,14 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
>>                   return ret;
>>               }
>>   
>> +            if (!(s->autoclear_features & QCOW2_AUTOCLEAR_DIRTY_BITMAPS) &&
>> +                s->nb_dirty_bitmaps > 0) {
>> +                ret = qcow2_delete_all_dirty_bitmaps(bs, errp);
>> +                if (ret < 0) {
>> +                    return ret;
>> +                }
>> +            }
>> +
> What if the file is read-only?
>
> We shouldn't modify the file in qcow2_read_extensions().
But where? In qcow2_open? Or nowhere? I think auto clear extensions 
should be cleared automatically..

-- 
Best regards,
Vladimir
* now, @virtuozzo.com instead of @parallels.com. Sorry for this inconvenience.