From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 4 Jul 2002 01:36:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 4 Jul 2002 01:36:33 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:48644 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Thu, 4 Jul 2002 01:36:32 -0400 Message-ID: <3D23E0C7.3B30B618@zip.com.au> Date: Wed, 03 Jul 2002 22:44:39 -0700 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.4.19-pre9 i686) X-Accept-Language: en MIME-Version: 1.0 To: Neil Brown CC: Jens Axboe , Joe Thornber , linux-lvm@sistina.com, linux-kernel@vger.kernel.org Subject: Re: [linux-lvm] LVM2 modifies the buffer_head struct? References: message from Jens Axboe on Wednesday July 3 <15651.54044.557070.109158@notabene.cse.unsw.edu.au> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Neil Brown wrote: > > ... > We just want ext3/jbd to make sure that it only calls bh2jh on > an unlocked buffer... is that easy? It's feasible, but a downright pita. > Ofcourse this ceases to be an issue in 2.5 because the filesys uses > pages or buffer_heads and the device driver uses bios. Well, for 2.4 I'd be inclined to just add the extra field to struct buffer_head and be done with it. Current sizeof(buffer_head) is 96 bytes, and making that 100 would be a nuisance, but its quite easy to shrink the buffer_head a bit (replace b_inode with BH_inode, say...). -