Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268765AbUIGXUo (ORCPT ); Tue, 7 Sep 2004 19:20:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268851AbUIGXRx (ORCPT ); Tue, 7 Sep 2004 19:17:53 -0400 Received: from mx02.qsc.de ([213.148.130.14]:5284 "EHLO mx02.qsc.de") by vger.kernel.org with ESMTP id S268759AbUIGXPe (ORCPT ); Tue, 7 Sep 2004 19:15:34 -0400 Date: Wed, 08 Sep 2004 01:14:25 +0200 From: Gunnar Ritter Organization: Privat. To: David Lang , Christer Weinigel Cc: Horst von Brand , viro@parcelfarce.linux.theplanet.co.uk, Linus Torvalds , Tonnerre , Spam , ReiserFS List , Hans Reiser , Pavel Machek , David Masover , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jamie Lokier , Christoph Hellwig , Alexander Lyamin aka FLX , Chris Wedgwood Subject: Re: silent semantic changes with reiser4 Message-ID: <413E40D1.nailFBI11XFML@pluto.uni-freiburg.de> References: <200409070206.i8726vrG006493@localhost.localdomain> <413D4C18.6090501@slaphack.com> <413DFF33.9090607@namesys.com> In-Reply-To: User-Agent: nail 11.7pre 9/8/04 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2192 Lines: 45 David Lang wrote: > so far the best answer that I've seen is a slight varient of what Hans is > proposing for the 'file-as-a-directory' > > make the base file itself be a serialized version of all the streams and > if you want the 'main' stream open file/. (or some similar varient) As has been said previously, all such proposals except for those with two leading slashes would directly violate POSIX.1-2004, Base Definitions, 4.11 'Pathname Resolution'. In particular, # A pathname that contains at least one non-slash character and that # ends with one or more trailing slashes shall be resolved as if a # single dot character ( '.' ) were appended to the pathname. A regular file name with special semantics, in contrast, would not violate POSIX, in particular if a stat() on it would not return one of the standard S_IFXXX types. Inappropriate operations could just fail with EINVAL on such files, and it would be unspecified by the standard how they were handled by 'cp' or other standardized utilities. Having a separate S_IFXXX type for streamed files would also give attention to portability issues easily. It might in fact be better to have existing applications fail explicitly with them than to make this as transparent as possible, but hope for good luck. Utilities like 'tar' would just say 'Unknown file type' or the like and exclude such files from the archives they create. This would lead the user's explicit attention to the data loss. He might then choose to ignore the error, or to get a special version of 'tar' to handle it. It would also be clear to programmers and users that such files are special things they don't normally need. Regular Linux installations might totally ignore them. If streamed files are only intended for use with CIFS or other special cases, that might be a more clean solution for this issue than watering down the existing portable file semantics. Gunnar - 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/