From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:52283) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gznzg-0003oU-2T for qemu-devel@nongnu.org; Fri, 01 Mar 2019 14:38:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gznzd-0001M6-Tj for qemu-devel@nongnu.org; Fri, 01 Mar 2019 14:38:51 -0500 References: <20190301191545.8728-1-jsnow@redhat.com> <20190301191545.8728-5-jsnow@redhat.com> From: Eric Blake Message-ID: <47e13575-6bb7-1374-4f7a-7d5029560393@redhat.com> Date: Fri, 1 Mar 2019 13:38:35 -0600 MIME-Version: 1.0 In-Reply-To: <20190301191545.8728-5-jsnow@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 4/7] block/dirty-bitmaps: prohibit readonly bitmaps for backups List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: Max Reitz , Fam Zheng , Kevin Wolf , Markus Armbruster , vsementsov@virtuozzo.com, "Dr. David Alan Gilbert" , Stefan Hajnoczi , Juan Quintela On 3/1/19 1:15 PM, John Snow wrote: > drive and blockdev backup cannot use readonly bitmaps, because the > sync=incremental mechanism actually edits the bitmaps on success. > > If you really want to do this operation, use a copied bitmap. In fact, that's what I ended up doing in my libvirt patches, always running sync=incremental on a temporary copy. Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org