From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54559) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XigLS-00044w-3Y for qemu-devel@nongnu.org; Mon, 27 Oct 2014 05:12:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XigLJ-0002G9-O2 for qemu-devel@nongnu.org; Mon, 27 Oct 2014 05:12:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55048) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XigLJ-0002G5-G6 for qemu-devel@nongnu.org; Mon, 27 Oct 2014 05:12:01 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s9R9C1re027984 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Mon, 27 Oct 2014 05:12:01 -0400 Message-ID: <544E0C5E.1030401@redhat.com> Date: Mon, 27 Oct 2014 10:11:58 +0100 From: Max Reitz MIME-Version: 1.0 References: <1414159063-25977-1-git-send-email-mreitz@redhat.com> <1414159063-25977-12-git-send-email-mreitz@redhat.com> <544A7CE9.4090905@redhat.com> In-Reply-To: <544A7CE9.4090905@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v14 11/14] qemu-img: Specify backing file for commit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake , qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi On 2014-10-24 at 18:23, Eric Blake wrote: > On 10/24/2014 07:57 AM, Max Reitz wrote: >> Introduce a new parameter for qemu-img commit which may be used to >> explicitly specify the backing file into which an image should be >> committed if the backing chain has more than a single layer. >> >> Signed-off-by: Max Reitz >> --- >> qemu-img-cmds.hx | 4 ++-- >> qemu-img.c | 32 +++++++++++++++++++++++--------- >> qemu-img.texi | 12 +++++++++++- >> 3 files changed, 36 insertions(+), 12 deletions(-) >> >> +If the backing chain of the given image file @var{filename} has more than one >> +layer, the backing file into which the changes will be committed may be >> +specified as @var{base} (which has to be part of @var{filename}'s backing >> +chain). If @var{base} is not specified, the immediate backing file of the top >> +image (which is @var{filename}) will be used. For reasons of consistency, >> +explicitly specifying @var{base} will always imply @code{-d} (otherwise, an >> +image could be committed in an indirect backing file and emptying it might lead >> +to different data being read from it because the intermediate backing chain >> +overrules the commit target). > I wonder if there is any better wording to make it obvious that both > instances of 'it' in the (comment) refer to the further reference of the > top image, and not the closer reference to the indirect backing file. Maybe: > > ...always imply -d (since emptying an image after committing to an > indirect backing file would lead to different data being read from the > image due to content in the intermediate backing chain overruling the > commit target) > > But I can live with the wording as you proposed it, so: > > Reviewed-by: Eric Blake Seems better to me; I'll change it if I respin (I'm looking forward to it by now), and if for some strange reason I will not respin I would be fine with the maintainer changing it accordingly, too. Max