From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33446) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UsDtD-0002If-9w for qemu-devel@nongnu.org; Thu, 27 Jun 2013 11:13:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UsDt4-0004zr-FR for qemu-devel@nongnu.org; Thu, 27 Jun 2013 11:13:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17560) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UsDt4-0004z8-7D for qemu-devel@nongnu.org; Thu, 27 Jun 2013 11:13:30 -0400 Message-ID: <51CC5677.4040200@redhat.com> Date: Thu, 27 Jun 2013 09:12:55 -0600 From: Eric Blake MIME-Version: 1.0 References: <1372341154-3594-1-git-send-email-pl@kamp.de> In-Reply-To: <1372341154-3594-1-git-send-email-pl@kamp.de> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="----enig2DJDLKAMKWQMWWKWWGIMB" Subject: Re: [Qemu-devel] [PATCH] block: change default of .has_zero_init to 0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: kwolf@redhat.com, josh.durgin@dreamhost.com, morita.kazutaka@gmail.com, tailai.ly@taobao.com, qemu-devel@nongnu.org, rjones@redhat.com, stefanha@redhat.com, bharata@linux.vnet.ibm.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) ------enig2DJDLKAMKWQMWWKWWGIMB Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 06/27/2013 07:52 AM, Peter Lieven wrote: > .has_zero_init defaults to 1 for all formats and protocols. >=20 > this is a dangerous default since this means that all > new added drivers need to manually overwrite it to 0 if > they do not ensure that a device is zero initialized > after bdrv_create(). >=20 > if a driver needs to explicitly set this value to > 1 its easier to verify the correctness in the review process. >=20 > during review of the existing drivers it turned out > that ssh and gluster had a wrong default of 1. > both protocols support host_devices as backend > which are not by default zero initialized. this > wrong assumption will lead to possible corruption > if qemu-img convert is used to write to such a backend. >=20 > a similar problem with the wrong default existed for > iscsi mose likely because the driver developer did s/mose/most/ --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org ------enig2DJDLKAMKWQMWWKWWGIMB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJRzFZ3AAoJEKeha0olJ0NqAg0H/01Pwtrw8XJ3SkEi22lRaXFJ efEUFUsriucU+CLEg9i73RlH+QRpwd+TBo4AbPHRBrp39HKDQgnZseheTSJFWIah nRiImlVtYxuCW+G8/HCd3G1Ird1XRk7y81biwqifZwaXfeJDAHw+9EMelsokOEye ZPe4A/bkT8pUlauf0FYGlRuxHE1HzU+6SWGnUNctAXcN5lU0ZAevW3Q6ulyh8UBp TitxcKhacLbHcNPnTC6g+7NV5c5hDjexUnBZYf2GcEdQ66hrT+hrSsMjuDeAgjuE YEQwSqLajEcmMpMSCbiLDuMCTbt6+vFOqER85QM+69JmZ8sKAPJyq9ddtC6lh4A= =hhio -----END PGP SIGNATURE----- ------enig2DJDLKAMKWQMWWKWWGIMB--