From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34941) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V1Dxi-0001k8-UC for qemu-devel@nongnu.org; Mon, 22 Jul 2013 07:07:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V1Dxh-0000uU-Ij for qemu-devel@nongnu.org; Mon, 22 Jul 2013 07:07:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7908) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V1Dxh-0000uK-Al for qemu-devel@nongnu.org; Mon, 22 Jul 2013 07:07:29 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6MB7S1o008680 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 22 Jul 2013 07:07:28 -0400 Message-ID: <51ED1262.4000000@redhat.com> Date: Mon, 22 Jul 2013 13:07:14 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1374464794-13057-1-git-send-email-famz@redhat.com> <1374464794-13057-2-git-send-email-famz@redhat.com> <51ECD26A.80104@redhat.com> <20130722064834.GA1992@T430s.redhat.com> In-Reply-To: <20130722064834.GA1992@T430s.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/2] block: allow live commit of active image List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: famz@redhat.com Cc: kwolf@redhat.com, jcody@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com Il 22/07/2013 08:48, Fam Zheng ha scritto: >> > I have only skimmed the patch, but I think this is incomplete. >> > Management needs to know the moment when 'active' is not valid anymore, >> > thus this job needs to be completed manually with "block-job-complete". > Does management need access to 'active' image outside of QEMU process? > Although original 'active' it is "dropped" by bdrv_drop_intermediate, > the pointers to original 'active' is still valid because 'base' is moved > to this address (with bdrv_swap). I don't know, what is the problem here > for management? Management needs to know, in case of a crash in QEMU or management itself at exactly the right time, whether any I/O have been issued by the guest to the 'base'. The only way to do this is, at this time, something like stop block-job-complete ide0-hd0 cont Paolo