Re: [Qemu-devel] [PATCH] xen_disk: treat "aio" as "raw"

[Alexander Graf <agraf@suse.de>]

On 06/30/2011 04:20 PM, Stefano Stabellini wrote:
> On Thu, 30 Jun 2011, Alexander Graf wrote:
>> On 06/30/2011 02:47 PM, Kevin Wolf wrote:
>>> Am 30.06.2011 13:47, schrieb Alexander Graf:
>>>> On 06/24/2011 04:50 PM, stefano.stabellini@eu.citrix.com wrote:
>>>>> From: Stefano Stabellini<stefano.stabellini@eu.citrix.com>
>>>>>
>>>>> Sometimes the toolstack uses "aio" without an additional format
>>>>> identifier, in such cases use "raw".
>>>> Shouldn't this rather be a patch to the toolstack then? We do automatic
>>>> file format recognition as default. I find magical "aio equals raw"
>>>> subtleties rather unintuitive.
>>> The asynchronous raw blktap driver is (was?) called "aio", so I guess
>>> it's to stay compatible with that. Has always been this way in Xen (and
>>> has always been confusing). As long as it stays in xen_disk.c, I don't
>>> really mind...
>> Is there a realistic chance of changing the toolstack here? I'd really
>> prefer not to drag this legacy around :).
> We could change the toolstack but it would mean introducing an
> incompatibility between the qdisk backend and the blktap backend.
> Considering that qdisk was written to replace blktap in the first place
> I don't think is such a good idea. Besides all xen toolstacks have
> always written "aio" for "raw" even before qdisk came along...

Hrm. Ok. Please resend with braces then :).


Alex