From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 3 Sep 2002 14:24:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 3 Sep 2002 14:24:09 -0400 Received: from dsl-213-023-043-116.arcor-ip.net ([213.23.43.116]:36245 "EHLO starship") by vger.kernel.org with ESMTP id ; Tue, 3 Sep 2002 14:24:08 -0400 Content-Type: text/plain; charset=US-ASCII From: Daniel Phillips To: ptb@it.uc3m.es, Lars Marowsky-Bree Subject: Re: [RFC] mount flag "direct" Date: Tue, 3 Sep 2002 20:31:18 +0200 X-Mailer: KMail [version 1.3.2] Cc: "Peter T. Breuer" , linux kernel References: <200209031641.g83GfnD10219@oboe.it.uc3m.es> In-Reply-To: <200209031641.g83GfnD10219@oboe.it.uc3m.es> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 03 September 2002 18:41, Peter T. Breuer wrote: > > Distributed filesystems have a lot of subtle pitfalls - locking, cache > > Yes, thanks, I know. > > > coherency, journal replay to name a few - which you can hardly solve at > > the > > My simple suggestion is not to cache. I am of the opinion that in > principle that solves all coherency problems, since there would be no > stored state that needs to "cohere". The question is how to identify > and remove the state that is currently cached. Well, for example, you would not be able to have the same file open in two different kernels because the inode would be cached. So you'd have to close the root directory on one kernel before the other could access any file. Not only would that be horribly inefficient, you would *still* need to implement a locking protocol between the two kernels to make it work. There's no magic way of making this easy. -- Daniel