From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38128) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c6Jaj-0005iz-Jf for qemu-devel@nongnu.org; Mon, 14 Nov 2016 10:54:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c6Jai-00024m-Jw for qemu-devel@nongnu.org; Mon, 14 Nov 2016 10:54:41 -0500 Date: Mon, 14 Nov 2016 16:54:28 +0100 From: Kevin Wolf Message-ID: <20161114155428.GA9518@noname.str.redhat.com> References: <8b945cd9-a601-4c81-495f-c1837f8d8231@redhat.com> <20161114095007.GA4755@noname.str.redhat.com> <62d2eccd-6399-a23a-cb82-4ceae58228d8@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="h31gzZEtNLTqOjlF" Content-Disposition: inline In-Reply-To: <62d2eccd-6399-a23a-cb82-4ceae58228d8@redhat.com> Subject: Re: [Qemu-devel] Assertion failure on qcow2 disk with cluster_size != 64k List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: Ed Swierk , qemu-block@nongnu.org, qemu-devel@nongnu.org, "Denis V. Lunev" --h31gzZEtNLTqOjlF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Am 14.11.2016 um 16:46 hat Eric Blake geschrieben: > On 11/14/2016 03:50 AM, Kevin Wolf wrote: > > Am 24.10.2016 um 22:32 hat Eric Blake geschrieben: > >> On 10/21/2016 08:14 AM, Ed Swierk wrote: > >>> On Thu, Oct 20, 2016 at 6:38 PM, Eric Blake wrote: > >>>> On 10/20/2016 07:24 PM, Ed Swierk wrote: > >>>>> Changing max_transfer in the normal write case to > >>>>> MIN_NON_ZERO(alignment, MAX_WRITE_ZEROES_BOUNCE_BUFFER) appears to = fix > >>>>> the problem, but I don't pretend to understand all the subtleties > >>>>> here. > >>>> > >>>> That actually sounds like the right fix. But since the bug was prob= ably > >>>> caused by my code, I'll formalize it into a patch and see if I can > >>>> modify the testsuite to give it coverage. > >>> > >>> If alignment > MAX_WRITE_ZEROES_BOUNCE_BUFFER (however unlikely) we > >>> have the same problem, so maybe this would be better? > >> > >> Our qcow2 support is currently limited to a maximum of 2M clusters; > >> while MAX_WRITE_ZEROES_BOUNCE_BUFFER is 32k * 512, or 16M. The > >> maximum-size bounce buffer should not be the problem here; but for some > >> reason, it looks like alignment is larger than max_transfer which shou= ld > >> not normally be possible. I'm still playing with what should be the > >> right patch, but hope to have something posted soon. > >=20 > > Are you still playing with it? >=20 > Patch was posted here: >=20 > https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg01603.html Ah, yes, sorry. I didn't make the connection today because this one had qcow2 in the subject line and the patch doesn't. Are you going to add a qemu-iotests case then, or do you want us to merge the patch as it is? Kevin --h31gzZEtNLTqOjlF Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJYKd40AAoJEH8JsnLIjy/WttMP/jZyJAlXi/WDsA4ForaTdNEp U8E49e9YPnEUOsL5tmmKTPA/O55dQmhvlVBOPc9vc1t/MV4RJrT/hzkWGcrlWAf2 bVTXJkgdbzsK05IXgvi7LCga3b0eaKAZqn3tLwmIRj93VMTSdoxEUFHxSEA8yDKq nQ3ubdwpwwwdUQ0OC0H5hqQjwnzZWXfQOQzIYYrDnbpy9Kp7ao6Fh5gN3Lf57Ijp TFBoy7A5gBiRyGrsv4AbybGPgFKts4/19TM2aRdpyjT0ZcF+D7k9vIw7yjZkzEjf mvIolemYJNkmTYOahCU6Ar6fgaIMnYvNcOVJYymXpowpItqO+7qWrxV2LEM4bKU1 nQCkm8xTsvY2lnsLws+S3WAM1c6pvCwVVqtsKSK8OB2dAzkZPMUWiIYU8cFx4coV euxLh+Bj+LFHpc2QEWCLVXmGPxl7/6yX3Zd/0WJ2jgq8RZRToFrGWIosPbLP7frK hJgV0oIN7m6Xed+YRpq+2oMsrcYkaCFaC/MA/J2GN6XAKuAKs/GXMgvtZHjkB4uh lckTvlEMiqL0wybHZV12OpUYKLHmKwy6zxo4n/ILhd0dbKrkD8tzNEWHz450G0Ha 7PmxJjot9Be/9WqHaobBxLYTKiCU+4O7EbUGvQbxWPGr4vRROCXprTGO4qozCtMl VHMGeH6zfvvJAWNhEPvi =tB0H -----END PGP SIGNATURE----- --h31gzZEtNLTqOjlF--