From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MLeDH-0001zz-69 for qemu-devel@nongnu.org; Tue, 30 Jun 2009 10:21:35 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MLeDC-0001yI-6K for qemu-devel@nongnu.org; Tue, 30 Jun 2009 10:21:34 -0400 Received: from [199.232.76.173] (port=59997 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MLeDC-0001y3-0h for qemu-devel@nongnu.org; Tue, 30 Jun 2009 10:21:30 -0400 Received: from mx20.gnu.org ([199.232.41.8]:23004) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MLeDB-00082A-IM for qemu-devel@nongnu.org; Tue, 30 Jun 2009 10:21:29 -0400 Received: from mail.codesourcery.com ([65.74.133.4]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MLeDA-0003dp-Jf for qemu-devel@nongnu.org; Tue, 30 Jun 2009 10:21:28 -0400 From: Paul Brook Subject: Re: [Qemu-devel] [PATCH] Warn if a qcow (not qcow2) file is opened Date: Tue, 30 Jun 2009 15:21:24 +0100 References: <1246284289-25394-1-git-send-email-avi@redhat.com> <4A4A13F7.8050904@codemonkey.ws> <4A4A19B7.3070600@redhat.com> In-Reply-To: <4A4A19B7.3070600@redhat.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200906301521.26152.paul@codesourcery.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Avi Kivity , kvm@vger.kernel.org > >>> The qcow block driver format is no longer maintained and likely > >>> contains > >>> serious data corruptors. Urge users to stay away for it, and advertise > >>> the new and improved replacement. > > > > I'm not sure how I feel about this. Can we prove qcow is broken? Is > > it only broken for writes and not reads? > > Well, Kevin posted a patch, so it is. It's definitely unmaintained. > Given it's a qemu native format, there is no interoperability value > except with old qemu versions. > > > If we're printing a warning, does that mean we want to deprecate qcow > > and eventually remove it (or remove write support, at least)? > > Yes. IMHO there's little value in just printing a warning. Until it actually goes away, people are liable to assume we're just being paranoid/awkward and keep using it anyway. I suggest crippling it now and, assuming noone steps up to fix+maintain it, ripping out the write support altogether at next release. I'm assuming the readonly code is in better shape, and can be supported with relatively little effort. Paul