From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:52693) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QcIHo-0002UJ-46 for qemu-devel@nongnu.org; Thu, 30 Jun 2011 10:32:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QcIHl-0001si-GB for qemu-devel@nongnu.org; Thu, 30 Jun 2011 10:32:07 -0400 Received: from cantor2.suse.de ([195.135.220.15]:50610 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QcIHl-0001sS-5T for qemu-devel@nongnu.org; Thu, 30 Jun 2011 10:32:05 -0400 Message-ID: <4E0C88E3.40006@suse.de> Date: Thu, 30 Jun 2011 16:32:03 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1308927034-10209-1-git-send-email-stefano.stabellini@eu.citrix.com> <1308927034-10209-2-git-send-email-stefano.stabellini@eu.citrix.com> <4E0C6263.20908@suse.de> <4E0C7047.3010909@redhat.com> <4E0C6FED.7080508@suse.de> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] xen_disk: treat "aio" as "raw" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefano Stabellini Cc: Kevin Wolf , "xen-devel@lists.xensource.com" , "qemu-devel@nongnu.org" 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 >>>>> >>>>> 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH] xen_disk: treat "aio" as "raw" Date: Thu, 30 Jun 2011 16:32:03 +0200 Message-ID: <4E0C88E3.40006@suse.de> References: <1308927034-10209-1-git-send-email-stefano.stabellini@eu.citrix.com> <1308927034-10209-2-git-send-email-stefano.stabellini@eu.citrix.com> <4E0C6263.20908@suse.de> <4E0C7047.3010909@redhat.com> <4E0C6FED.7080508@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Stefano Stabellini Cc: Kevin Wolf , "xen-devel@lists.xensource.com" , "qemu-devel@nongnu.org" List-Id: xen-devel@lists.xenproject.org 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 >>>>> >>>>> 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