From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49062) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eFhhz-0003qw-8A for qemu-devel@nongnu.org; Fri, 17 Nov 2017 09:33:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eFhhy-0008Ol-AJ for qemu-devel@nongnu.org; Fri, 17 Nov 2017 09:33:31 -0500 References: <20171103144113.7188-1-berrange@redhat.com> <9b0c5170-c97a-51d5-b1e4-003f1628d7be@redhat.com> <20171110172253.GH30685@redhat.com> From: Eric Blake Message-ID: Date: Fri, 17 Nov 2017 08:33:22 -0600 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="l9veilP6tVEmuJBGtnjj4gxwfn9KB89fe" Subject: Re: [Qemu-devel] [PATCH] qcow2: fix image corruption after committing qcow2 image into base List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz , "Daniel P. Berrange" Cc: qemu-devel@nongnu.org, Kevin Wolf , qemu-block@nongnu.org, Vladimir Sementsov-Ogievskiy This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --l9veilP6tVEmuJBGtnjj4gxwfn9KB89fe From: Eric Blake To: Max Reitz , "Daniel P. Berrange" Cc: qemu-devel@nongnu.org, Kevin Wolf , qemu-block@nongnu.org, Vladimir Sementsov-Ogievskiy Message-ID: Subject: Re: [Qemu-devel] [PATCH] qcow2: fix image corruption after committing qcow2 image into base References: <20171103144113.7188-1-berrange@redhat.com> <9b0c5170-c97a-51d5-b1e4-003f1628d7be@redhat.com> <20171110172253.GH30685@redhat.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 11/14/2017 07:52 AM, Max Reitz wrote: >>> Hmm - I wonder if persistent bitmaps are also corrupted in the fast p= ath. >> >> I also wonder if there's anything better we can do to make us safer by= >> default, so we default to the slow & safe path, unless we can provide >> we *only* have the subset of features that are safe for the fast path = ? >=20 > I have wondered the same but I can't think of any. The only thing that= > comes close would be to check for which header extensions there are; bu= t > at the same time, we could just add a comment to qcow2_read_extensions(= ) > ("If you add a new feature to qcow2, note that you may want to adjust > the qcow2_make_empty() fastpath conditions"). Indeed, such a comment may be helpful. --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org --l9veilP6tVEmuJBGtnjj4gxwfn9KB89fe Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAloO8zIACgkQp6FrSiUn Q2p34AgAq3KeWiXfqej0B99RC2QwvrOA7WjEGlZMiPKIvqR4FqTLSnNTVHrRh2ZU d5nPXQHabjoXKSXwOV9j0aAM05PDe7udsnCzxGD4HFXZPujFPIzIjofzrpKBkFda Dhg0T+AiAURt5zVqQ0MpiZIOwtNUe/Ub4WgEH5AtZaWPUaWNEWHCfxop2dyI4Of/ tuKCFrA7B2402JGaWY8n1CQXmWV4FVFw1LEcTavl4dYxn+OxPh9H+DKHF1I6LR1X nZKbx/XEQyTc3kIDyqb8g38zXty9F1FwaUNuOOWoGyF70mM75DfA5TN3o9VJSZHq za1Na7JHwHpy2v/N3r8XOkWOTO+Hjg== =kQE9 -----END PGP SIGNATURE----- --l9veilP6tVEmuJBGtnjj4gxwfn9KB89fe--