Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263505AbUCYRty (ORCPT ); Thu, 25 Mar 2004 12:49:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263526AbUCYRtx (ORCPT ); Thu, 25 Mar 2004 12:49:53 -0500 Received: from mail.shareable.org ([81.29.64.88]:24977 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S263505AbUCYRtu (ORCPT ); Thu, 25 Mar 2004 12:49:50 -0500 Date: Thu, 25 Mar 2004 17:49:42 +0000 From: Jamie Lokier To: "Eric W. Biederman" Cc: =?iso-8859-1?Q?J=F6rn?= Engel , Davide Libenzi , "Patrick J. LoPresti" , Linux Kernel Mailing List Subject: Re: [PATCH] cowlinks v2 Message-ID: <20040325174942.GC11236@mail.shareable.org> References: <20040321125730.GB21844@wohnheim.fh-wedel.de> <20040321181430.GB29440@wohnheim.fh-wedel.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 894 Lines: 21 Eric W. Biederman wrote: > Actually there is... You don't do the copy until an actual write occurs. > Some files are opened read/write when there is simply the chance they might > be written to so delaying the copy is generally a win. Programs depend on the inode number returned by fstat() not changing, and maybe in some other circumstances, even if they subsequently write to the file. (It's ok for open() to change the inode number, because that's equivalent to another program changing the filesystem in parallel). How do you handle that if COW occurs later than open()? You could also force COW when fstat() is called, I suppose. -- 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/