From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52449) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZlfvU-00027P-LV for qemu-devel@nongnu.org; Mon, 12 Oct 2015 12:26:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZlfvT-0003Qu-LV for qemu-devel@nongnu.org; Mon, 12 Oct 2015 12:26:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48331) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZlfvT-0003Qq-Gr for qemu-devel@nongnu.org; Mon, 12 Oct 2015 12:26:15 -0400 References: <1444446115-3796-1-git-send-email-crosthwaite.peter@gmail.com> <561BD814.5090005@redhat.com> From: Eric Blake Message-ID: <561BDF26.4070405@redhat.com> Date: Mon, 12 Oct 2015 10:26:14 -0600 MIME-Version: 1.0 In-Reply-To: <561BD814.5090005@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="JC7qshtOXJKmCdilTCdt4j4RLHcc5mX1q" Subject: Re: [Qemu-devel] [RFC] Block device size rounding List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow , Peter Crosthwaite , qemu-devel@nongnu.org Cc: kwolf@redhat.com, saipava@xilinx.com, stefanha@redhat.com, Peter Crosthwaite This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --JC7qshtOXJKmCdilTCdt4j4RLHcc5mX1q Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 10/12/2015 09:56 AM, John Snow wrote: >> What is the correct action here though? If the file is writeable shoul= d >> we just allow the device to extend its size? Is that possible already?= >> Just zero-pad read-only? >> >=20 > Read-only seems like an easy case of append zeroes. Yes, allowing read-only with append-zero behavior seems sane. >=20 > Read-write ... well, we can't write-protect just half of a 512k block. > Probably just forcibly increasing the size on RW or refusing to use the= > file altogether are probably the sane deterministic things we want. I'd lean towards outright rejection if the file size isn't up to snuff for use as read-write. Forcibly increasing the size (done unconditionally) still feels like magic, and may not be possible if the size is due to something backed by a block device rather than a file. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --JC7qshtOXJKmCdilTCdt4j4RLHcc5mX1q 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/ iQEcBAEBCAAGBQJWG98mAAoJEKeha0olJ0Nq3FwH/3gP/Gedzb7kk0t34NnOrBKN PO5kdG6Y4ZPRo3LGnwY57/aDWpVeeGurWREh4cs70rGHFTpuSJABBnfsYRbtUeLd n1Bn/3LOSliyyKOdeHFKdzA0t3XQfBRodinpO3hbx2dVjQXsH6X6K24RnXwXZrbp kFYjZZWzpuUqdT52zaNbD70itSjzMWcGX9aAU+19MRmEr+lY1iqW3lrVa6rntjuo nLmbyTdckBNndAYAPR87YgIKeP7Rv6SmRzlvrCTSh0Yw1vM98MB9HGlCERGtVsek rMGBNndZAOV6oUA0jO1Wc/ZnrjdZc6leVDXi8yDxXO8ny5lyST+t9Y4rtBmUhyE= =VFXA -----END PGP SIGNATURE----- --JC7qshtOXJKmCdilTCdt4j4RLHcc5mX1q--