From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:54013) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S38ei-0005IP-8h for qemu-devel@nongnu.org; Thu, 01 Mar 2012 11:15:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S38ed-0000ZL-Kx for qemu-devel@nongnu.org; Thu, 01 Mar 2012 11:14:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:17548) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S38ed-0000Xk-CH for qemu-devel@nongnu.org; Thu, 01 Mar 2012 11:14:55 -0500 Message-ID: <4F4FA13C.6030307@redhat.com> Date: Thu, 01 Mar 2012 17:18:04 +0100 From: Kevin Wolf MIME-Version: 1.0 References: <1330600908-16202-1-git-send-email-pbonzini@redhat.com> <20120301130250.46c2377e@doriath.home> In-Reply-To: <20120301130250.46c2377e@doriath.home> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 0/6] Mirrored writes using blockdev-transaction List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luiz Capitulino Cc: aliguori@us.ibm.com, stefanha@linux.vnet.ibm.com, jcody@redhat.com, qemu-devel@nongnu.org, fsimonce@redhat.com, Paolo Bonzini , eblake@redhat.com Am 01.03.2012 17:02, schrieb Luiz Capitulino: > On Thu, 1 Mar 2012 12:21:42 +0100 > Paolo Bonzini wrote: > >> This implements all ingredients to establish mirrored writes. > > This looks good to me. I just have two comments: > > 1. I'm wondering if it would make more sense to have this transaction > operation in qmp instead of the block layer. Looks more complex to do though, > so I'm ok with this implementation Depends on what you're thinking of. Renaming the command to just 'transaction' and allowing anything to be added to the union wouldn't be very complex. The one thing we would need to change in order to make it generally useful is to move the actual logic into prepare/commit/abort handlers. I discussed this with Paolo on IRC and I think the conclusion was that for now the approach in the patches is good enough, but in the long run we'll switch. It doesn't affect external interfaces, so we can do it whenever we like. Kevin