From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1K20D8-0007Wh-Hb for qemu-devel@nongnu.org; Fri, 30 May 2008 04:43:43 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1K20D5-0007Vi-2d for qemu-devel@nongnu.org; Fri, 30 May 2008 04:43:40 -0400 Received: from [199.232.76.173] (port=39339 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1K20D3-0007VU-Ll for qemu-devel@nongnu.org; Fri, 30 May 2008 04:43:37 -0400 Received: from main.gmane.org ([80.91.229.2]:42127 helo=ciao.gmane.org) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1K20D3-0006KM-Hc for qemu-devel@nongnu.org; Fri, 30 May 2008 04:43:37 -0400 Received: from list by ciao.gmane.org with local (Exim 4.43) id 1K20Cw-0002d3-U4 for qemu-devel@nongnu.org; Fri, 30 May 2008 08:43:31 +0000 Received: from adsl-99-146-176-105.dsl.irvnca.sbcglobal.net ([99.146.176.105]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 30 May 2008 08:43:30 +0000 Received: from m.bevand by adsl-99-146-176-105.dsl.irvnca.sbcglobal.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 30 May 2008 08:43:30 +0000 From: Marc Bevand Date: Fri, 30 May 2008 08:43:18 +0000 (UTC) Message-ID: References: <18493.11141.847907.619324@mariner.uk.xensource.com> <18493.11264.309358.483993@mariner.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: news Subject: [Qemu-devel] Re: [RFC] Allow 'qemu-img convert' to preserve the backing file Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Ian Jackson eu.citrix.com> writes: > > If there were a generic way to ask a block driver for a cow format > what the backing image filename was, then the block driver core could > do the opening itself. That would make everything a bit simpler as it > would move code out of the invididual drivers. I am done. I implemented this feature in a generic way as you suggested. I am going to send the patch in a separate email. I am confident in its robustness, so far I have successfully converted more than 20 copy-on-write qcow1 images to the qcow2 format. Different sizes, different "ages" (between 0 and 90% of the sectors rewritten in the COW copies), different guest filesystems, etc. I have verified no corruption occured by making sure a final conversion to the raw format led to the expected MD5 checksum. -marc