From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:60290) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R1F2q-0006qC-4x for qemu-devel@nongnu.org; Wed, 07 Sep 2011 06:07:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R1F2p-0001aD-94 for qemu-devel@nongnu.org; Wed, 07 Sep 2011 06:07:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40558) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R1F2p-0001Zx-1A for qemu-devel@nongnu.org; Wed, 07 Sep 2011 06:07:47 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p87A7jiE018805 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 7 Sep 2011 06:07:45 -0400 Message-ID: <4E67426D.1040702@redhat.com> Date: Wed, 07 Sep 2011 13:07:41 +0300 From: Avi Kivity MIME-Version: 1.0 References: <1315387463-14623-1-git-send-email-avi@redhat.com> <4E673FC6.60007@redhat.com> In-Reply-To: <4E673FC6.60007@redhat.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] qcow2: make cache=unsafe usable List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: qemu-devel@nongnu.org On 09/07/2011 12:56 PM, Kevin Wolf wrote: > Am 07.09.2011 11:24, schrieb Avi Kivity: > > Currently cache=unsafe is unsafe to the point of unusability - the > > caches are never written to disk except on exit so anything except > > an orderly exit -- including live migration -- leaves the disk image > > corrupted. > > > > Fix by interpreting flush requests and doing everything except flushing > > the underlying file. The contents of the metadata cache are transferred > > to the host pagecache, so that qemu aborts keep the disk in a consistent > > state, and live migration (on the same host, or if using a coherent > > filesystem) works. > > > > Signed-off-by: Avi Kivity > > --- > > > > Untested - is this the right approach? > > Hm, could work, even though I don't like it very much. The alternative > approach would be something like this I think that your version is better - it fixes all the layered format drivers at once (even though qcow2 is the only one that needs fixing). -- error compiling committee.c: too many arguments to function