Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261416AbUDCB73 (ORCPT ); Fri, 2 Apr 2004 20:59:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261528AbUDCB73 (ORCPT ); Fri, 2 Apr 2004 20:59:29 -0500 Received: from mail.shareable.org ([81.29.64.88]:28054 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S261416AbUDCB72 (ORCPT ); Fri, 2 Apr 2004 20:59:28 -0500 Date: Sat, 3 Apr 2004 02:59:20 +0100 From: Jamie Lokier To: andersen@codepoet.org, Pavel Machek , =?iso-8859-1?Q?J=F6rn?= Engel , mj@ucw.cz, jack@ucw.cz, "Patrick J. LoPresti" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] cowlinks v2 Message-ID: <20040403015920.GA2857@mail.shareable.org> References: <20040329231635.GA374@elf.ucw.cz> <20040402165440.GB24861@wohnheim.fh-wedel.de> <20040402180128.GA363@elf.ucw.cz> <20040402181707.GA28112@wohnheim.fh-wedel.de> <20040402182357.GB410@elf.ucw.cz> <20040402200921.GC653@mail.shareable.org> <20040402213933.GB246@elf.ucw.cz> <20040403010425.GJ653@mail.shareable.org> <20040403012112.GA6499@codepoet.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040403012112.GA6499@codepoet.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 659 Lines: 20 Erik Andersen wrote: > > Here's a tricky situation: > > > > 1. A file is cowlinked. Then each cowlink is mmap()'d, one per process. > > > > 2. At this point both mappings share the same pages in RAM. > > > > 3. Then one of the cowlinks is written to... > > Using mmap with PROT_WRITE on a cowlink must preemptively > break the link. I forget to mention, they are PROT_READ shared mappings. -- Jamie - 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/