From mboxrd@z Thu Jan 1 00:00:00 1970 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 Message-ID: <200906301521.26152.paul@codesourcery.com> References: <1246284289-25394-1-git-send-email-avi@redhat.com> <4A4A13F7.8050904@codemonkey.ws> <4A4A19B7.3070600@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Anthony Liguori , Kevin Wolf , kvm@vger.kernel.org To: qemu-devel@nongnu.org Return-path: Received: from mail.codesourcery.com ([65.74.133.4]:38119 "EHLO mail.codesourcery.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751203AbZF3OVY (ORCPT ); Tue, 30 Jun 2009 10:21:24 -0400 In-Reply-To: <4A4A19B7.3070600@redhat.com> Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: > >>> The qcow block driver format is no longer maintained and likely 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