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Date: Tue, 16 Jul 2013 09:54:46 +0200
From: Peter Lieven <pl@kamp.de>
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Subject: Re: [Qemu-devel] [PATCH 16/17] block: add default get_block_status
 implementation for protocols
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com

On 16.07.2013 09:19, Paolo Bonzini wrote:
> Il 16/07/2013 08:47, Peter Lieven ha scritto:
>>> @@ -2977,7 +2977,11 @@ static int64_t coroutine_fn
>>> bdrv_co_get_block_status(BlockDriverState *bs,
>>>          if (!bs->drv->bdrv_co_get_block_status) {
>>>            *pnum = nb_sectors;
>>> -        return BDRV_BLOCK_DATA;
>>> +        ret = BDRV_BLOCK_DATA;
>>> +        if (bs->drv->protocol_name) {
>>> +            ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num *
>>> BDRV_SECTOR_SIZE);
>>> +        }
>>> +        return ret;
>>>        }
>>>          ret = bs->drv->bdrv_co_get_block_status(bs, sector_num,
>>> nb_sectors, pnum);
>> I am curious if this is right. Doesn't this mean we say that at offset
>> sector_num * BDRV_SECTOR_SIZE are nb_sectors of linear data? This is
>> something we do not know for sure.
> Only for protocols.  In this case, we do know, or format=raw wouldn't
> work.  This is not propagated up to the actual BDS for the image, except
> for format=raw.
If bs->drv->protocol_name is only != NULL if format=raw, I am
fine with this.

Peter