From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265597AbUBFTzJ (ORCPT ); Fri, 6 Feb 2004 14:55:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265602AbUBFTzI (ORCPT ); Fri, 6 Feb 2004 14:55:08 -0500 Received: from almesberger.net ([63.105.73.238]:30731 "EHLO host.almesberger.net") by vger.kernel.org with ESMTP id S265597AbUBFTzD (ORCPT ); Fri, 6 Feb 2004 14:55:03 -0500 Date: Fri, 6 Feb 2004 16:54:58 -0300 From: Werner Almesberger To: Matthias Urlichs Cc: linux-kernel@vger.kernel.org Subject: Re: VFS locking: f_pos thread-safe ? Message-ID: <20040206165458.D18820@almesberger.net> References: <402359E1.6000007@ntlworld.com> <20040206011630.42ed5de1.akpm@osdl.org> <40235DCC.2060606@ntlworld.com> <20040206013523.394d89f1.akpm@osdl.org> <20040206111853.GE21151@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ; from smurf@smurf.noris.de on Fri, Feb 06, 2004 at 07:59:45PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Matthias Urlichs wrote: > but it's NOT AT ALL obvious to a "normal" application programmer. It gets worse. From the same draft (perhaps someone who has the final version could comment ?), in the rationale for read(): | The standard developers considered adding atomicity requirements to a | pipe or FIFO, but recognized that due to the nature of pipes and FIFOs | there could be no guarantee of atomicity of reads of {PIPE_BUF} or any | other size that would be an aid to applications portability. But then | I/O is intended to be atomic to ordinary files and pipes and FIFOs. Now, what exactly does "intended" mean ? Of course, in this part, they only talk about data staying together, not whether it can get duplicated, or effects on f_pos. - Werner -- _________________________________________________________________________ / Werner Almesberger, Buenos Aires, Argentina wa@almesberger.net / /_http://www.almesberger.net/____________________________________________/