From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54483) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YqhVB-0004Oi-HT for qemu-devel@nongnu.org; Fri, 08 May 2015 08:35:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YqhV4-0005Wg-Bd for qemu-devel@nongnu.org; Fri, 08 May 2015 08:35:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58607) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YqhV4-0005Wc-3D for qemu-devel@nongnu.org; Fri, 08 May 2015 08:35:30 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t48CZT9D011200 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Fri, 8 May 2015 08:35:29 -0400 Message-ID: <554CAD90.3060300@redhat.com> Date: Fri, 08 May 2015 06:35:28 -0600 From: Eric Blake MIME-Version: 1.0 References: <1431078628-7856-1-git-send-email-pbonzini@redhat.com> <87zj5ffkea.fsf@blackfin.pond.sub.org> <554C8FAF.1080207@redhat.com> In-Reply-To: <554C8FAF.1080207@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Emovjfrgjg20Cs12Vd0fvXrxMSkHQxTvd" Subject: Re: [Qemu-devel] [PATCH v2] qemu-nbd: only send a limited number of errno codes on the wire List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , Markus Armbruster Cc: kwolf@redhat.com, mreitz@redhat.com, "Richard W.M. Jones" , qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --Emovjfrgjg20Cs12Vd0fvXrxMSkHQxTvd Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 05/08/2015 04:27 AM, Paolo Bonzini wrote: >=20 >=20 > On 08/05/2015 12:12, Markus Armbruster wrote: >>> The corresponding patch to the NBD protocol description can be found = at >>> http://article.gmane.org/gmane.linux.drivers.nbd.general/3154. >=20 > [...] >=20 >>> - EFBIG is part of the universal set of errors, but it is also change= d >>> to ENOSPC because it is pretty similar to ENOSPC or EDQUOT. >> >> Perhaps debatable, but I defer to your judgement. >=20 > EFBIG is weird anyway, and requires you (or your parents) to ignore > SIGXFSZ. A simpler protocol puts fewer requirements on the client. Not only that, but if I understand correctly, the only way to trigger SIGXFSZ or EFBIG is to compile your application to use a smaller off_t than the maximum the system supports. That is, it is impossible on 64-bit Linux, and on 32-bit Linux is it possible only when you use 32-bit off_t instead of 64-bit off_t. But we are dealing with guest disk images, and practically require 64-bit off_t to make it useful for all but the oldest of guests. >=20 > (In fact, we probably should ignore SIGXFSZ in QEMU and treat EFBIG lik= e > ENOSPC everywhere. Should doesn't mean that it will get on anyone's > todo list or priority list...). and if I'm right above, it wouldn't make a difference anyway. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --Emovjfrgjg20Cs12Vd0fvXrxMSkHQxTvd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJVTK2QAAoJEKeha0olJ0NqeCgH/1qogs8V6h+yfB2HzHg0xbaG qe1bnCmBibJGW/RSfI8O5RklXX9lhmbvCEmmcVCCltOz6oOdUv/e5K8hLuS2nKb1 wlyvIWm+PzyFlami4/n0rkE+notWaZzmGqjhswHr9M4eiWzwmoAgAFYGqpWxqJU+ A0UDp8TKotFj5/7y9OaNEg7r3UaLzEk06w7GOLHdEZOdPVk3p7SbJeYW6Gzj22eq deQYhOBFesoMiUpEWHcofLTPnT2BXogdHSsHzdnFQjxGreJYG/FyuMtlF8GtGNuW tepclo0ckmDikpEB+5NRxBWuyennMlHSu/kCob3d3Wx0O5UComtyHwsmGdWHqaA= =AGIe -----END PGP SIGNATURE----- --Emovjfrgjg20Cs12Vd0fvXrxMSkHQxTvd--