Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261246AbUDCBVj (ORCPT ); Fri, 2 Apr 2004 20:21:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261505AbUDCBVj (ORCPT ); Fri, 2 Apr 2004 20:21:39 -0500 Received: from codepoet.org ([166.70.99.138]:63430 "EHLO codepoet.org") by vger.kernel.org with ESMTP id S261246AbUDCBVi (ORCPT ); Fri, 2 Apr 2004 20:21:38 -0500 Date: Fri, 2 Apr 2004 18:21:12 -0700 From: Erik Andersen To: Jamie Lokier Cc: 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: <20040403012112.GA6499@codepoet.org> Reply-To: andersen@codepoet.org Mail-Followup-To: andersen@codepoet.org, Jamie Lokier , Pavel Machek , =?iso-8859-1?Q?J=F6rn?= Engel , mj@ucw.cz, jack@ucw.cz, "Patrick J. LoPresti" , linux-kernel@vger.kernel.org References: <20040329171245.GB1478@elf.ucw.cz> <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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040403010425.GJ653@mail.shareable.org> X-No-Junk-Mail: I do not want to get *any* junk mail. User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 747 Lines: 22 On Sat Apr 03, 2004 at 02:04:25AM +0100, Jamie Lokier 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. -Erik -- Erik B. Andersen http://codepoet-consulting.com/ --This message was written using 73% post-consumer electrons-- - 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/