From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LuwDl-0003YX-EW for qemu-devel@nongnu.org; Fri, 17 Apr 2009 18:07:41 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LuwDe-0003YB-Q4 for qemu-devel@nongnu.org; Fri, 17 Apr 2009 18:07:40 -0400 Received: from [199.232.76.173] (port=50817 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LuwDe-0003Y8-JJ for qemu-devel@nongnu.org; Fri, 17 Apr 2009 18:07:34 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:52507) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LuwDe-000144-4H for qemu-devel@nongnu.org; Fri, 17 Apr 2009 18:07:34 -0400 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e36.co.us.ibm.com (8.13.1/8.13.1) with ESMTP id n3HM63ZL001710 for ; Fri, 17 Apr 2009 16:06:03 -0600 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n3HM7Xmd207508 for ; Fri, 17 Apr 2009 16:07:33 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n3HM7WpD001594 for ; Fri, 17 Apr 2009 16:07:32 -0600 Message-ID: <49E8FDA1.2030505@us.ibm.com> Date: Fri, 17 Apr 2009 17:07:29 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 1/5] qcow2: Fix warnings in check_refcount() References: <1239969879-5611-1-git-send-email-kwolf@redhat.com> <200904172300.34596@kevin-wolf.de> <49E8EEAE.6000403@us.ibm.com> <200904172319.55735@kevin-wolf.de> In-Reply-To: <200904172319.55735@kevin-wolf.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Kevin Wolf , Christoph Hellwig , qemu-devel@nongnu.org Kevin Wolf wrote: > Am Freitag, 17. April 2009 23:03 schrieb Anthony Liguori: > >> I'm basically at the point of not wanting to touch qcow2 without serious >> testing. That said, I can do enough on my own to satisfy me so I'll >> commit this series later today or tomorrow. >> > > I perfectly understand that you don't want to break it again. But then, the > only way to avoid new bugs is to stop development completely. This isn't a > solution either. > Every patch I commit gets tested. I have various tests that I run depending on which subsystem the patch touches. Right now, for qcow2, I don't have nearly enough. I was hoping that Christoph had something laying around that I could use since it looks like qemu-io would be a great harness for qcow2 changes. But I can write a pretty easy script myself on top of qemu-io so it's no big deal. I'm not suggesting holding up development. > This is even more true for changes which are actually made for testing and > debugging purposes like these. This series is what helped me to find the > corruption bug. > > What we should do is to make sure that qcow2 patches (especially those > touching the core) are given a thorough review before committing. > In theory, r5006 did. That wasn't enough. >>> And even though I think that this series can't break anything, we >>> definitely could use a strong test suite. I'm almost sure that there is >>> at least one bug left (the one Jamie Lokier saw from 5006 on, but nobody >>> ever found it). >>> >> You don't think that was Nolan's fix? >> > > Hm, I haven't look very much in detail at it. But according to the commit log > only qcow_is_allocated() was affected, and I can't see how booting Jamie's > Windows guest would call this function. > The bug was in get_cluster_offset() so it could have caused much more subtle breakages. -- Regards, Anthony Liguori