From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268272AbUH2S5w (ORCPT ); Sun, 29 Aug 2004 14:57:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268273AbUH2S5w (ORCPT ); Sun, 29 Aug 2004 14:57:52 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:64984 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S268272AbUH2S5t (ORCPT ); Sun, 29 Aug 2004 14:57:49 -0400 Date: Sun, 29 Aug 2004 19:57:44 +0100 From: viro@parcelfarce.linux.theplanet.co.uk To: Hans Reiser Cc: flx@msu.ru, Paul Jackson , riel@redhat.com, ninja@slaphack.com, torvalds@osdl.org, diegocg@teleline.es, jamie@shareable.org, christophe@saout.de, vda@port.imtp.ilyichevsk.odessa.ua, christer@weinigel.se, spam@tnonline.net, akpm@osdl.org, wichert@wiggy.net, jra@samba.org, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, flx@namesys.com, reiserfs-list@namesys.com Subject: Re: silent semantic changes with reiser4 Message-ID: <20040829185744.GQ21964@parcelfarce.linux.theplanet.co.uk> References: <412F7D63.4000109@namesys.com> <20040827230857.69340aec.pj@sgi.com> <20040829150231.GE9471@alias> <4132205A.9080505@namesys.com> <20040829183629.GP21964@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040829183629.GP21964@parcelfarce.linux.theplanet.co.uk> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 29, 2004 at 07:36:29PM +0100, viro@parcelfarce.linux.theplanet.co.uk wrote: > > he wants without recompiling to do it. This kind of a view requires no > > coding because you can just mount the root filesystem two ways, one with > > the -nopseudos mount option, and one without it. > > *What*? > > OK, now I want detailed explanation of the reasons why that doesn't create > cache coherency problems. > > Do you have an analysis of locking in the entire thing? And I am very, very serious about that - we are talking about very nasty minefield and design choices in that area have fundamental impact on the entire layer, wherever it is located. It's *NOT* something that you can leave until later and hope it somehow falls into place - it can be merged in steps, but you MUST know the goal on that level. To rearchitect later might be possible (even though you will a hell of a time avoiding plugins breakage), but it will be *hard*.