From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:39556) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SV2xc-0003x9-Ob for qemu-devel@nongnu.org; Thu, 17 May 2012 11:49:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SV2xa-0001vw-OE for qemu-devel@nongnu.org; Thu, 17 May 2012 11:49:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51112) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SV2xa-0001vr-FX for qemu-devel@nongnu.org; Thu, 17 May 2012 11:49:50 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q4HFnmoc023930 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 17 May 2012 11:49:48 -0400 Message-ID: <4FB51E1B.9080602@redhat.com> Date: Thu, 17 May 2012 09:49:47 -0600 From: Eric Blake MIME-Version: 1.0 References: <1337268840-4779-1-git-send-email-rjones@redhat.com> In-Reply-To: <1337268840-4779-1-git-send-email-rjones@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig609AAF0594C859B9C4EE5871" Subject: Re: [Qemu-devel] [PATCH v3] qemu-img: Implement 'diff' operation. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Richard W.M. Jones" Cc: qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig609AAF0594C859B9C4EE5871 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 05/17/2012 09:34 AM, Richard W.M. Jones wrote: > From: "Richard W.M. Jones" >=20 > This produces a qcow2 file which is the difference between > two disk images. ie, if: >=20 > base.img - is a disk image (in any format) > modified.img - is base.img, copied and modified >=20 > then: >=20 > qemu-img diff -b base.img modified.img diff.qcow2 >=20 > creates 'diff.qcow2' which contains the differences between 'base.img' > and 'modified.img'. Note that 'diff.qcow2' has 'base.img' as its > backing file. >=20 > Signed-off-by: Richard W.M. Jones > Cc: Matthew Booth > Cc: Pablo Iranzo G=C3=B3mez > Cc: Tomas Von Veschler Regarding the documentation and command overview: Reviewed-by: Eric Blake Regarding the actual logic used in computing the diff, I did not closely look at that, and you would be wise to get a review from someone more familiar with block dev operations. --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enig609AAF0594C859B9C4EE5871 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJPtR4bAAoJEKeha0olJ0NqU90H/3+4F8KGQu9oXlMng+/Oemuf g+uOPfOSIDFdeejxU7lDTaBiN/LTY4bYJ3cFOzNYlJGPdF7FkkKmk4PRLLI5Uj18 CjK/JxF5ZhpvJaYKvw9I0LEdCIYv4riNs5PAqoGqm/8oVvKAfNY4lj+Y94+6+6e8 O2J7cmdbNouBxWdGWwcKYVUMmmnJMAHscO26vtog3YU44wU/Sd84hC1z53vXePmK IppXrJV6QF7I6JRhaTm9/GsGZQtT9zIw3qrTIyKTObD3Oz37Elta4yFlQC2/gJV2 yKCR8zmzPqS/4AJpXTG4iIgdQuSgYbizH9YxRrlYsnMilkrweA9jMXNEwy8iuhE= =npqE -----END PGP SIGNATURE----- --------------enig609AAF0594C859B9C4EE5871--