From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266841AbUBQXVo (ORCPT ); Tue, 17 Feb 2004 18:21:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266866AbUBQXUt (ORCPT ); Tue, 17 Feb 2004 18:20:49 -0500 Received: from dp.samba.org ([66.70.73.150]:50358 "EHLO lists.samba.org") by vger.kernel.org with ESMTP id S266841AbUBQXUP (ORCPT ); Tue, 17 Feb 2004 18:20:15 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16434.39473.822318.998268@samba.org> Date: Wed, 18 Feb 2004 09:48:17 +1100 To: Neil Brown Cc: Linus Torvalds , Kernel Mailing List , Al Viro Subject: Re: UTF-8 and case-insensitivity In-Reply-To: <16433.53708.264048.307137@notabene.cse.unsw.edu.au> References: <16433.38038.881005.468116@samba.org> <16433.47753.192288.493315@samba.org> <16433.53708.264048.307137@notabene.cse.unsw.edu.au> X-Mailer: VM 7.18 under Emacs 21.3.1 Reply-To: tridge@samba.org From: tridge@samba.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Neil, > I thought the value of a case-insensitive filenames was for > legacy applications which have been written to the WIN32 API and took > lots of liberties with "pretty-casing" filenames between readdir and > open. No, thats a common misconception. It does happen (the "pretty-casing") but its relatively rare these days. The real problem is *proving* that a file doesn't exist. If a file does exist then there are all sorts of heuristic and cache mechanisms that can be used to get the real filename quickly on average, but if you have to prove absolutely that a file does not exist then all of that stuff is pretty much useless. Samba (and any other system that wants case-insensitive semantics on Linux) can't make do with "oh, it probably doesn't exist". That way leads to data loss. You have to know with 100% certainty that the file doesn't exist in any case combination. Unfortunately, that is also the hardest thing to do. Cheers, Tridge