From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33452) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c6Du5-0002q0-Dz for qemu-devel@nongnu.org; Mon, 14 Nov 2016 04:50:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c6Du4-0007mw-Mg for qemu-devel@nongnu.org; Mon, 14 Nov 2016 04:50:17 -0500 Date: Mon, 14 Nov 2016 10:50:07 +0100 From: Kevin Wolf Message-ID: <20161114095007.GA4755@noname.str.redhat.com> References: <8b945cd9-a601-4c81-495f-c1837f8d8231@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="UlVJffcvxoiEqYs2" Content-Disposition: inline In-Reply-To: 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" --UlVJffcvxoiEqYs2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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 probab= ly > >> caused by my code, I'll formalize it into a patch and see if I can > >> modify the testsuite to give it coverage. > >=20 > > If alignment > MAX_WRITE_ZEROES_BOUNCE_BUFFER (however unlikely) we > > have the same problem, so maybe this would be better? >=20 > 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 should > not normally be possible. I'm still playing with what should be the > right patch, but hope to have something posted soon. Are you still playing with it? Kevin --UlVJffcvxoiEqYs2 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJYKYjPAAoJEH8JsnLIjy/WGdsP/177db0+IEFZumgLZA8/PRmU CK3MvKuBupPdrkdi65W9h+xD/cRYotB1cV0G1TRWeORc0Aeu/ZxZul9TrfbPQ8bv uBQz68pPt3Gtf3eQF5t/xoRW0HspgA9s/yLQwEs3T9s6WdaYRRC9QN0/iiHJ8eTS pq2GqvnSWjEL6yfSam5Sux0hDqC3dnsH/jUo1Azx7jnB+1F5xMIW6WNgyAMb8l0U mof0/WLZ7SMeX96primTDY24JlvxcgD0yWRwVGAUvJK6tK7McrlYBMIzBoRcXrFI A6V9dkml4lVi1jYAV62J3hLb+K26AMmn1uidfIDQNGFWifEZD7rhbNhZfWLbrjt7 /8AWiR1ubio/FPp+I8HLApuMBZtCK0UxwAVsTeldP8bGgbXHIEGXE+riZsjDTdin 1MUqBf6DYETsL8sGqeVKurKtDKZVfyxmXeoXOQGy01ShOx/6XpszYOSUVMZmNR+g YW/jskCn4bHlsKN22t2/6Jh1zbVlEAjw9gIVyJdNbUWpVcDlN/UznGHg2kBNHY+5 VtO9Mq5o6SvW4uX45n6MnbJqe8vnVZ9uW4/I1s27qbw5JlkcUzBWIqNtILGNwRHI JgG+JiLsVqZtOF6zoWTrxGBwhmZwOgK09cUKWOuTJPtE1kxwa3QdG3OBNDWmqoYF XfpNwyqYRlOd75vIz18c =w0jJ -----END PGP SIGNATURE----- --UlVJffcvxoiEqYs2--