From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58784) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WxXKt-0004UL-Av for qemu-devel@nongnu.org; Thu, 19 Jun 2014 04:04:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WxXKk-0003xD-96 for qemu-devel@nongnu.org; Thu, 19 Jun 2014 04:04:43 -0400 Received: from mail-wi0-x232.google.com ([2a00:1450:400c:c05::232]:37687) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WxXKk-0003wa-1T for qemu-devel@nongnu.org; Thu, 19 Jun 2014 04:04:34 -0400 Received: by mail-wi0-f178.google.com with SMTP id n15so2354877wiw.17 for ; Thu, 19 Jun 2014 01:04:33 -0700 (PDT) Date: Thu, 19 Jun 2014 16:04:24 +0800 From: Stefan Hajnoczi Message-ID: <20140619080424.GN21236@stefanha-thinkpad.redhat.com> References: <1012a7b01df79acb1e963656b7829816c7f1b81d.1403041699.git.jcody@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="SgT04PEqo/+yUDw3" Content-Disposition: inline In-Reply-To: <1012a7b01df79acb1e963656b7829816c7f1b81d.1403041699.git.jcody@redhat.com> Subject: Re: [Qemu-devel] [PATCH v6 for 2.1 08/10] block: add backing-file option to block-stream List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jeff Cody Cc: kwolf@redhat.com, benoit.canet@irqsave.net, pkrempa@redhat.com, famz@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com --SgT04PEqo/+yUDw3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 17, 2014 at 05:53:56PM -0400, Jeff Cody wrote: > On some image chains, QEMU may not always be able to resolve the > filenames properly, when updating the backing file of an image > after a block job. >=20 > For instance, certain relative pathnames may fail, or drives may > have been specified originally by file descriptor (e.g. /dev/fd/???), > or a relative protocol pathname may have been used. >=20 > In these instances, QEMU may lack the information to be able to make > the correct choice, but the user or management layer most likely does > have that knowledge. >=20 > With this extension to the block-stream api, the user is able to change > the backing file of the active layer as part of the block-stream > operation. >=20 > This allows the change to be 'safe', in the sense that if the attempt > to write the active image metadata fails, then the block-stream > operation returns failure, without disrupting the guest. >=20 > If a backing file string is not specified in the command, the backing > file string to use is determined in the same manner as it was > previously. >=20 > Reviewed-by: Eric Blake > Signed-off-by: Jeff Cody > --- > block/stream.c | 11 +++++------ > blockdev.c | 12 ++++++++++++ > hmp.c | 3 ++- > qapi/block-core.json | 18 +++++++++++++++++- > qmp-commands.hx | 2 +- > 5 files changed, 37 insertions(+), 9 deletions(-) Reviewed-by: Stefan Hajnoczi --SgT04PEqo/+yUDw3 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJTopmIAAoJEJykq7OBq3PI9QsH/3i8Nn1wLH7ih0rEvtXP64CX J8UMD9soPY4b7n72w9u7aLPMzbGjdE8ll3296a9e7i1Vfj4INImOQTnyKztkZNML aaRdn55EFI6BDOkuyYoP2APKfzALNFQqrvzXOJdaUQOv8Mq0WSYxu5RIaHz7xXip IMpmNY9bbU/LKy59vj9WhQo4Kw4WwNM2xS5HLXh3bmPhS3DyagQNghBVofz3yBWX dWxdgX4GI2b5pduyzyzR0oTwVq56QWFWwGOJb8LrgJsh7kX94jSXag9mljbd//nv ZjkPnkU5eTbO64SUOUTlZL/CKAEXdI5RD/JEWal1WHG2X3CTqnaejanUR0Rwllc= =qnio -----END PGP SIGNATURE----- --SgT04PEqo/+yUDw3--