From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60968) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1anB4o-0004Cy-Uc for qemu-devel@nongnu.org; Mon, 04 Apr 2016 16:26:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1anB4k-0001aE-U2 for qemu-devel@nongnu.org; Mon, 04 Apr 2016 16:26:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58745) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1anB4k-0001a1-MR for qemu-devel@nongnu.org; Mon, 04 Apr 2016 16:26:18 -0400 References: <1459787950-15286-1-git-send-email-eblake@redhat.com> <7AD0DCB1-1868-4AAD-A03D-C976A728DD75@alex.org.uk> <5702C1AB.8020601@redhat.com> <5702C8C3.1050300@openvz.org> From: Eric Blake Message-ID: <5702CDE8.6000805@redhat.com> Date: Mon, 4 Apr 2016 14:26:16 -0600 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="55pqqihhKejTVqKaxjdregi4eqKcMD3XI" Subject: Re: [Qemu-devel] [Nbd] [PATCH v2] doc: Add NBD_CMD_BLOCK_STATUS extension List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Bligh , "Denis V. Lunev" Cc: "nbd-general@lists.sourceforge.net" , Kevin Wolf , "qemu-devel@nongnu.org" , Pavel Borzenkov , "Stefan stefanha@redhat. com" , Wouter Verhelst , Paolo Bonzini This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --55pqqihhKejTVqKaxjdregi4eqKcMD3XI Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 04/04/2016 02:08 PM, Alex Bligh wrote: >=20 > On 4 Apr 2016, at 21:04, Denis V. Lunev wrote: >=20 >>> Sure, but given you can't report dirtiness without also reporting >>> allocation, if they are are at different blocksize I'd rather they >>> were in different commands, because otherwise the code to report >>> block size needs to work at two different granularities. >>> >> 'dirty' could come after the data was 'trimmed' from the region! >> thus we could have dirty unallocated data. >=20 > Let me rephrase. >=20 > Under the current proposal it is not possible to report whether or > not a region is dirty without also reporting whether or not it > is allocated. Huh? The current proposal _requires_ these to be separate queries. You cannot query dirtiness at the same time as allocation, because the value of NBD_CMD_FLAG_DIRTY is distinct between the two queries. > As these two concepts exist at potentially > different block sizes, the code to support reporting on allocation > must now be able to run both at the allocation blocksize and > the dirtiness blocksize, which is going to be a pain. No, the code for reporting allocation does NOT have to be run at the same time as when reporting dirtiness. >=20 > If these were two different commands, they could each run at their > natural block size. Both modes of operation already can run at their natural block size. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --55pqqihhKejTVqKaxjdregi4eqKcMD3XI 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/ iQEcBAEBCAAGBQJXAs3pAAoJEKeha0olJ0NqkY0IAJgRtfs0eJ/76GIHmrzlX8PR 4d4xVP/IaocmZzzCrbeFSkFHvCOnu1pmday6gfabLFz3gawPwBis7oMf5oPT8J3D NDQ5Nx10rtWqJuDQiyit9YGoY5CshcH7wkF8bsyNLyvP93PoYn5ti96WWa/eufaA LoTktSNL6GyGnPqWzA1BPmrYVC35taxcKGXd5cQQi6sP6l/3YMM2azJpBXJwhUc2 uBcafhYfqftu/zEPZ6p8Ha1Mpm4BW1Vxx6rgwlHa/ocYQ/ydwxAN+dfgursXHe8D dnAzTErqxnLrZJB3Rn2Ot48gTiHJAxDobIGxI2FFgcRT6r86tnt+ca5+J+07rkI= =ipLm -----END PGP SIGNATURE----- --55pqqihhKejTVqKaxjdregi4eqKcMD3XI--