From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752956Ab1GVIXg (ORCPT ); Fri, 22 Jul 2011 04:23:36 -0400 Received: from mail-fx0-f52.google.com ([209.85.161.52]:65267 "EHLO mail-fx0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752800Ab1GVIXb (ORCPT ); Fri, 22 Jul 2011 04:23:31 -0400 Date: Fri, 22 Jul 2011 11:21:09 +0300 (EEST) From: Pekka Enberg X-X-Sender: penberg@tiger To: Kevin Wolf cc: linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, levinsasha928@gmail.com, tglx@linutronix.de, linux-tip-commits@vger.kernel.org, kvm-devel Subject: Re: [tip:tools/kvm] kvm tools, qcow: Fix copy-on-write image corruption In-Reply-To: <4E27DEA9.20404@redhat.com> Message-ID: References: <4E27DEA9.20404@redhat.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 21 Jul 2011, Kevin Wolf wrote: > Hm, I must have missed this patch on the KVM mailing list... It wasn't on the list, sorry. > You should also error out before creating a new L2 table as its refcount > would have to be updated, too. On the other hand, the patch is a bit too > restrictive, because it applies the check to qcow1 which doesn't even > have a refcount table. Oh, right, I broken QCOW1. > I'm not sure if everyone is aware of it, so another hint: Now that you > can't grow qcow2 any more, you might find it useful to use qemu-img > create -f qcow2 -o preallocation=metadata, so that all clusters are > already present and you don't get random failures. Yup, I'm aware that you can't grow images anymore. The patch was meant as a stop-gap measure while I'm hacking on refcount table support. Pekka