From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32856) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vl1y4-0004Ta-KT for qemu-devel@nongnu.org; Mon, 25 Nov 2013 14:37:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vl1xz-0004ox-OL for qemu-devel@nongnu.org; Mon, 25 Nov 2013 14:37:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9806) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vl1xz-0004ot-FU for qemu-devel@nongnu.org; Mon, 25 Nov 2013 14:37:07 -0500 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 rAPJb6dL013338 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 25 Nov 2013 14:37:06 -0500 Message-ID: <5293A6E0.9090804@redhat.com> Date: Mon, 25 Nov 2013 12:37:04 -0700 From: Eric Blake MIME-Version: 1.0 References: <1385407736-13941-1-git-send-email-mreitz@redhat.com> <1385407736-13941-2-git-send-email-mreitz@redhat.com> In-Reply-To: <1385407736-13941-2-git-send-email-mreitz@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="xBEs8JgDMjFJXE2lmeHvBx52abSCtiure" Subject: Re: [Qemu-devel] [PATCH for-1.7 1/2] block/drive-mirror: Reuse backing HD for sync=none List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz , qemu-devel@nongnu.org Cc: Kevin Wolf , Paolo Bonzini , Stefan Hajnoczi This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --xBEs8JgDMjFJXE2lmeHvBx52abSCtiure Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 11/25/2013 12:28 PM, Max Reitz wrote: > For "none" sync mode in "absolute-paths" mode, the current image should= > be used as the backing file for the newly created image. >=20 > The current behavior is: > a) If the image to be mirrored has a backing file, use that (which is > wrong, since the operations recorded by "none" are applied to the > image itself, not to its backing file). > b) If the image to be mirrored lacks a backing file, the target doesn't= > have one either (which is not really wrong, but not really right, > either; "none" records a set of operations executed on the image > file, therefore having no backing file to apply these operations on > seems rather pointless). >=20 > For a, this is clearly a bugfix. For b, it is still a bugfix, although > it might break existing API - but since that case crashed qemu just > three weeks ago (before 1452686495922b81d6cf43edf025c1aef15965c0), we > can safely assume there is no such API relying on that case yet. >=20 > Suggested-by: Paolo Bonzini > Signed-off-by: Max Reitz > --- > blockdev.c | 3 +++ > 1 file changed, 3 insertions(+) Reviewed-by: Eric Blake And definitely agree that this is a bug fix worth having in 1.7, before we bake in borked semantics that libvirt would have to work around depending on qemu version. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --xBEs8JgDMjFJXE2lmeHvBx52abSCtiure Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJSk6bgAAoJEKeha0olJ0Nq7HMIAIyTmYOzGsQUjPPMrIVbAhTZ QdhAGESSU73d025TnBRMWr1+7uJYMIF555pDOzLdkNHEp1zmxEFCEhOHffaVjBo9 XVngFfahgMOQUcCiiA4wkqLgJkwa2HZgZC0cWn6g/OQKMjp5cYtsVzmII4k9XicP 7OtfJo522GBW81I2RrcvliH815WeRqv6sR6bdiMou3DsYj0Aeck6qxbpi0PYFO3z C8H58IK+sSz9J9vxbr5dYlTMcTyGulB4wcWKyw6rsYeGm7spITVJ+3hRvOBgzshv S4NJ+5dDX97DohEy0y+7Dp34XL4DFYubfFovEXyojQt5q6o4aDiqx6F4rFtIfPI= =hcWt -----END PGP SIGNATURE----- --xBEs8JgDMjFJXE2lmeHvBx52abSCtiure--