Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking

[Paolo Bonzini]

Il 06/03/2013 19:32, Jeff Cody ha scritto:
> On Wed, Mar 06, 2013 at 06:50:56PM +0100, Peter Lieven wrote:
>> Looking at the source I have not found a place where bs->growable is set to 
>> 0 for any
>> block driver, maybe I miss something. Having bs->growable for iSCSI would 
>> also be ok.
>>
>> Shouldn't it be possible to call bdrv_drain_all() any time? There are other 
>> places
>> where this is called. One I have in mind is e.g. if you cancel an ongoing 
>> block migration.
> 
> That is a good point - what happens to QCOW now, if there is a block
> job in progress (e.g. block-commit, block-stream, etc...)?  I would
> imagine -EBUSY gets thrown, since bdrv_truncate() checks
> bdrv_in_use().

No, bs->file is not marked in use.  Only bs is.

Paolo