From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268832AbUHZLSY (ORCPT ); Thu, 26 Aug 2004 07:18:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268767AbUHZLPP (ORCPT ); Thu, 26 Aug 2004 07:15:15 -0400 Received: from gate.firmix.at ([80.109.18.208]:40669 "EHLO gate.firmix.at") by vger.kernel.org with ESMTP id S268727AbUHZLLn (ORCPT ); Thu, 26 Aug 2004 07:11:43 -0400 Subject: Re: silent semantic changes with reiser4 From: Bernd Petrovitsch To: Spam Cc: Andrew Morton , jra@samba.org, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <742303812.20040826125114@tnonline.net> References: <20040824202521.GA26705@lst.de> <412CEE38.1080707@namesys.com> <20040825152805.45a1ce64.akpm@osdl.org> <112698263.20040826005146@tnonline.net> <1453698131.20040826011935@tnonline.net> <20040825163225.4441cfdd.akpm@osdl.org> <20040825233739.GP10907@legion.cup.hp.com> <20040825234629.GF2612@wiggy.net> <1939276887.20040826114028@tnonline.net> <20040826024956.08b66b46.akpm@osdl.org> <839984491.20040826122025@tnonline.net> <20040826032457.21377e94.akpm@osdl.org> <742303812.20040826125114@tnonline.net> Content-Type: text/plain Organization: Firmix Software GmbH Message-Id: <1093518671.2883.19.camel@tara.firmix.at> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.5.5 Date: Thu, 26 Aug 2004 13:11:11 +0200 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [ shortened Cc: of reiser- and other folks since it is no longer reiser-specific - sorry, if it was too much ] [ fixed missing attribution ] On Thu, 2004-08-26 at 12:51 +0200, Spam wrote: > On Thu, 2004-08-26 at 03:24 -0700, Andrew Morton wrote: > > Spam wrote: [...] > >> Applications that support the new features will benefit, all others > >> will continue to work without destroying data. > > > Sorry, but that all sounds a bit fluffy. Please provide some examples. It is too fluffy. > We already had the examples with cp and mv. Both should continue to > work and the files will still be copied. The same with Konqueror and ... after they are patched to support streams. As stated each stream has an own fd, so - from the user-space perspective - one has to open *all* streams of this file, read them and write them into the destination. > Nautilus. Files and their meta-files/streams/attributes will be > retained as long as applications are using the OS API. The OS-API is *one* file descriptor where you can read, write, mmap, ... on. Therefore stream selection must happen with open() since open() returns a fd (which uniquely identify a stream). Voila. And actually this makes transition actually possible: Old apps simply ignore streams (yes, there will be a default stream, which is used id nothing else is specified) and throw them away (think of e.g. patch which opens a new file, writes into it, unlink's the old one and mv's the new one on the old place) until they are modified to support them. Bernd -- Firmix Software GmbH http://www.firmix.at/ mobil: +43 664 4416156 fax: +43 1 7890849-55 Embedded Linux Development and Services