From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39887) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoYni-0002Ua-LL for qemu-devel@nongnu.org; Wed, 12 Nov 2014 09:21:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoYnc-00043f-D6 for qemu-devel@nongnu.org; Wed, 12 Nov 2014 09:21:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58830) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoYnc-00043U-5Q for qemu-devel@nongnu.org; Wed, 12 Nov 2014 09:21:32 -0500 Message-ID: <54636CE3.70808@redhat.com> Date: Wed, 12 Nov 2014 15:21:23 +0100 From: Max Reitz MIME-Version: 1.0 References: <1415627159-15941-1-git-send-email-mreitz@redhat.com> <1415627159-15941-19-git-send-email-mreitz@redhat.com> <54636C67.1010504@redhat.com> In-Reply-To: <54636C67.1010504@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 18/21] qcow2: Add function for refcount order amendment List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake , qemu-devel@nongnu.org Cc: Kevin Wolf , Peter Lieven , Stefan Hajnoczi On 2014-11-12 at 15:19, Eric Blake wrote: > On 11/10/2014 06:45 AM, Max Reitz wrote: >> Add a function qcow2_change_refcount_order() which allows changing the >> refcount order of a qcow2 image. > A thought: didn't you just submit a patch that marked the image as > dirty, nuked the on-disk refcount, then rebuilt one using the in-memory > refcounts? Would reusing THAT code be any better than writing this patch? Yes, I thought about that, too... The problem is that that patch requires all refcount blocks to fit in memory at the same time (or generally, the qcow2 check function requires that, for now). I'd really like to avoid that, if possible, but maybe it isn't possible after all. But if you say it like that ("nuke"), I guess I'll give it a try. Maybe it looks funny enough. Max