Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265839AbUAEB6a (ORCPT ); Sun, 4 Jan 2004 20:58:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265842AbUAEB6a (ORCPT ); Sun, 4 Jan 2004 20:58:30 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:28823 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S265839AbUAEB63 (ORCPT ); Sun, 4 Jan 2004 20:58:29 -0500 Date: Mon, 5 Jan 2004 01:58:28 +0000 From: viro@parcelfarce.linux.theplanet.co.uk To: Jeremy Maitin-Shepard Cc: linux-kernel@vger.kernel.org Subject: Re: udev and devfs - The final word Message-ID: <20040105015828.GA4176@parcelfarce.linux.theplanet.co.uk> References: <20040104000840.A3625@pclin040.win.tue.nl> <20040104034934.A3669@pclin040.win.tue.nl> <20040104142111.A11279@pclin040.win.tue.nl> <20040104230104.A11439@pclin040.win.tue.nl> <200401042335.i04NZqQZ029910@turing-police.cc.vt.edu> <87k747w4ow.fsf@jbms.ath.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87k747w4ow.fsf@jbms.ath.cx> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1187 Lines: 22 On Sun, Jan 04, 2004 at 08:43:27PM -0500, Jeremy Maitin-Shepard wrote: > Unfortunately, programs such as tar depend on inode numbers of distinct > files being distinct even when the file is not open over a period of > several minutes/seconds. This is needed to avoid dumping hard links > more than once. Furthermore, there is no efficient way to write > programs such as tar without depending on this capability. Thus, if > st_ino cannot be used reliably for this purpose, it would be useful for > there to be a system call for retrieving a true > unique-within-the-filesystem identifier for the file. No such thing. It's not the matter of having a syscall to extract such identifier - it's that on a lot of filesystems (including many common Unix ones) there's nothing that would qualify. Note that tar et.al. do not behave well if used on actively modified directory tree and ->st_ino reuse is the least of the problems in that area. - 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/