From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933142AbWKSUKs (ORCPT ); Sun, 19 Nov 2006 15:10:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933139AbWKSUKs (ORCPT ); Sun, 19 Nov 2006 15:10:48 -0500 Received: from mx1.suse.de ([195.135.220.2]:37012 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S933142AbWKSUKr (ORCPT ); Sun, 19 Nov 2006 15:10:47 -0500 Message-ID: <4560BAAF.2030202@suse.com> Date: Sun, 19 Nov 2006 15:12:31 -0500 From: Jeff Mahoney Organization: SUSE Labs, Novell, Inc User-Agent: Thunderbird 1.5 (X11/20060317) MIME-Version: 1.0 To: Andi Kleen Cc: Randy Dunlap , lkml , reiserfs-dev@namesys.com, sam@ravnborg.org, Al Viro Subject: Re: reiserfs NET=n build error References: <20061118202206.01bdc0e0.randy.dunlap@oracle.com> <200611190650.49282.ak@suse.de> <45608FC2.5040406@suse.com> <200611191959.55969.ak@suse.de> In-Reply-To: <200611191959.55969.ak@suse.de> X-Enigmail-Version: 0.94.0.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Andi Kleen wrote: >>> I would copy a relatively simple C implementation, like arch/h8300/lib/checksum.c >> As long as the h8300 version has the same output as the x86 version. > > The trouble is that the different architecture have different output > for csum_partial. So you already got a bug when someone wants to move > file systems. Yeah, Al Viro noticed that about reiserfs earlier this month. The problem is that there's really no good fix for it. I was under the impression that csum_partial would be arch-independent and was in asm/ for performance reasons. The comment in asm-x86_64 indicates that's not the case, but the comment in asm-i386 still doesn't. I developed the code on i386. Moving forward we can define an arch-independent hash function for that and accept the old arch-dependent checksums, but there's still the issue of old kernels not understanding it on any arch. Kind of a nice shot to the foot considering the work I put into making reiserfs endian safe in the 2.4 days. I'm hoping there's a better solution to be found than creating a checksum verifier that checks all known versions. :( - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFFYLqvLPWxlyuTD7IRAj7RAKCkOHL9EgTrmHSo97xzG5tBxWgzCACgiBcW uzd/oSwXDHECHPEcIL58xoo= =udEd -----END PGP SIGNATURE-----