From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752311AbXCEPVR (ORCPT ); Mon, 5 Mar 2007 10:21:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752002AbXCEPVQ (ORCPT ); Mon, 5 Mar 2007 10:21:16 -0500 Received: from mx1.redhat.com ([66.187.233.31]:52374 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751643AbXCEPVO (ORCPT ); Mon, 5 Mar 2007 10:21:14 -0500 Message-ID: <45EC3415.6000307@redhat.com> Date: Mon, 05 Mar 2007 07:15:33 -0800 From: Ulrich Drepper Organization: Red Hat, Inc. User-Agent: Thunderbird 1.5.0.9 (X11/20070212) MIME-Version: 1.0 To: Theodore Tso , Arnd Bergmann , Christoph Hellwig , Dave Kleikamp , Andrew Morton , "Amit K. Arora" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, suparna@in.ibm.com, cmm@us.ibm.com, alex@clusterfs.com, suzuki@in.ibm.com Subject: Re: [RFC] Heads up on sys_fallocate() References: <20070117094658.GA17390@amitarora.in.ibm.com> <1172789056.11165.42.camel@kleikamp.austin.ibm.com> <20070301233819.GB31072@infradead.org> <200703032345.33137.arnd@arndb.de> <0DA8B217-DDD4-4E05-B000-DEBE3BE55B94@cam.ac.uk> <45EB4A55.3060908@redhat.com> <8A8B28AA-3481-4CFF-AEAA-0CB4CCDFF9F9@cam.ac.uk> <20070305143703.GF26781@thunk.org> In-Reply-To: <20070305143703.GF26781@thunk.org> X-Enigmail-Version: 0.94.1.2.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig7CB176E9316BAC63D943D816" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7CB176E9316BAC63D943D816 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Theodore Tso wrote: > Given that glibc already has to support this for older kernels, I > would argue that there's no point putting in generic support for > filesystem that can't support a more advanced way of doing things. Well, I'm sure the kernel can do better than the code we have in libc now. The kernel has access to the bitmasks which say which blocks have already been allocated. The libc code does not and we have to be very simple-minded and simply touch every block. And this means reading it and then writing it back. The kernel would know when the reading part is not necessary. Add to then the block granularity (we use f_bsize as returned from fstatfs but that's not the best value in some cases) and you have compelling data to have generic code in the kernel. Then libc implementation can then go away completely which is a good thing. --=20 =E2=9E=A7 Ulrich Drepper =E2=9E=A7 Red Hat, Inc. =E2=9E=A7 444 Castro St = =E2=9E=A7 Mountain View, CA =E2=9D=96 --------------enig7CB176E9316BAC63D943D816 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFF7DQV2ijCOnn/RHQRAi9fAJ0b/PaSZBZvix28DBCddUOMTDE7mgCfYD7H 3WSVUkvsl9W+wg7aG5s4CNE= =776z -----END PGP SIGNATURE----- --------------enig7CB176E9316BAC63D943D816--