Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751092AbXACT0T (ORCPT ); Wed, 3 Jan 2007 14:26:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751091AbXACT0S (ORCPT ); Wed, 3 Jan 2007 14:26:18 -0500 Received: from frankvm.xs4all.nl ([80.126.170.174]:53746 "EHLO janus.localdomain" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751087AbXACT0S (ORCPT ); Wed, 3 Jan 2007 14:26:18 -0500 Date: Wed, 3 Jan 2007 20:26:16 +0100 From: Frank van Maarseveen To: Mikulas Patocka Cc: Jan Harkes , Pavel Machek , Arjan van de Ven , Miklos Szeredi , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: Finding hardlinks Message-ID: <20070103192616.GA3299@janus> References: <20061221185850.GA16807@delft.aura.cs.cmu.edu> <1166869106.3281.587.camel@laptopd505.fenrus.org> <20061229100223.GF3955@ucw.cz> <20070101235320.GS8104@delft.aura.cs.cmu.edu> <20070103185815.GA2182@janus> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i X-BotBait: val@frankvm.com, kuil@frankvm.com Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1499 Lines: 35 On Wed, Jan 03, 2007 at 08:17:34PM +0100, Mikulas Patocka wrote: > > On Wed, 3 Jan 2007, Frank van Maarseveen wrote: > > >On Tue, Jan 02, 2007 at 01:04:06AM +0100, Mikulas Patocka wrote: > >> > >>I didn't hardlink directories, I just patched stat, lstat and fstat to > >>always return st_ino == 0 --- and I've seen those failures. These failures > >>are going to happen on non-POSIX filesystems in real world too, very > >>rarely. > > > >I don't want to spoil your day but testing with st_ino==0 is a bad choice > >because it is a special number. Anyway, one can only find breakage, > >not prove that all the other programs handle this correctly so this is > >kind of pointless. > > > >On any decent filesystem st_ino should uniquely identify an object and > >reliably provide hardlink information. The UNIX world has relied upon this > >for decades. A filesystem with st_ino collisions without being hardlinked > >(or the other way around) needs a fix. > > ... and that's the problem --- the UNIX world specified something that > isn't implementable in real world. Sure it is. Numerous popular POSIX filesystems do that. There is a lot of inode number space in 64 bit (of course it is a matter of time for it to jump to 128 bit and more) -- Frank - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/