From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:37439) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TinAC-0005dX-Q1 for qemu-devel@nongnu.org; Wed, 12 Dec 2012 09:20:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TinA6-0003pg-EB for qemu-devel@nongnu.org; Wed, 12 Dec 2012 09:19:56 -0500 Received: from mail.univention.de ([82.198.197.8]:1227) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TinA6-0003pV-80 for qemu-devel@nongnu.org; Wed, 12 Dec 2012 09:19:50 -0500 From: Philipp Hahn Date: Wed, 12 Dec 2012 15:09:46 +0100 References: <1339767219-24297-1-git-send-email-kwolf@redhat.com> <201212121425.41850.hahn@univention.de> <50C8899D.2050308@redhat.com> In-Reply-To: <50C8899D.2050308@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart5996250.FsHpL2EA2O"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <201212121510.06575.hahn@univention.de> Subject: Re: [Qemu-devel] [BUG] qemu-1.1.2 [FIXED-BY] qcow2: Fix avail_sectors in cluster allocation code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Michael Tokarev , qemu-devel@nongnu.org --nextPart5996250.FsHpL2EA2O Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hello Kevin,=20 Am Mittwoch 12 Dezember 2012 14:41:49 schrieb Kevin Wolf: > As you can see in the commit message of that patch I was convinced that > no bug did exist in practice and this was only dangerous with respect to > future changes. Therefore my first question is if you're using an > unmodified upstream qemu or if some backported patches are applied to > it? If it's indeed unmodified, we should probably review the code once > again to understand why it makes a difference. This were all unmodified versions directly from git between "qemu-kvm-1.1.0= "=20 and "qemu-kvm-1.2.0" "git checkout b7ab0fea37c15ca9e249c42c46f5c48fd1a0943c" works, "git checkout b7ab0fea37c15ca9e249c42c46f5c48fd1a0943c~1" is broken. "git checkout qemu-kvm-1.1.2" is broken, "git checkout qemu-kvm-1.1.2 ; git cherry-pick=20 b7ab0fea37c15ca9e249c42c46f5c48fd1a0943c" works > In any case, this is the cluster allocation code. It's probably not > related to rereading things from disk, but rather to the writeout of the > page cache. Yes, the problem is probably write related. But as the write "doens't explo= de=20 with some spectacular error", I only notice the error on the following read= =20 by comparing md5 sums. I just re-checked it: After a reboot the md5sums are still invalid, so I gu= ess=20 the data is corrupted on writeout. Sincerely Philipp =2D-=20 Philipp Hahn Open Source Software Engineer hahn@univention.de Univention GmbH be open. fon: +49 421 22 232- 0 Mary-Somerville-Str.1 D-28359 Bremen fax: +49 421 22 232-99 http://www.univention.de/ --nextPart5996250.FsHpL2EA2O Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEABECAAYFAlDIkCoACgkQYPlgoZpUDjncwwCfR1rcKoSJefKji45qoKxQNd04 /b8An0/K+Few602ZjUB5ogVfIqYZPGK1 =gDO9 -----END PGP SIGNATURE----- --nextPart5996250.FsHpL2EA2O--