From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 8 Sep 2001 17:17:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 8 Sep 2001 17:17:04 -0400 Received: from h24-64-71-161.cg.shawcable.net ([24.64.71.161]:38134 "EHLO webber.adilger.int") by vger.kernel.org with ESMTP id ; Sat, 8 Sep 2001 17:16:51 -0400 From: Andreas Dilger Date: Sat, 8 Sep 2001 15:15:39 -0600 To: Linus Torvalds Cc: Andrea Arcangeli , Kernel Mailing List , Alexander Viro Subject: Re: linux-2.4.10-pre5 Message-ID: <20010908151539.F32553@turbolinux.com> Mail-Followup-To: Linus Torvalds , Andrea Arcangeli , Kernel Mailing List , Alexander Viro In-Reply-To: <20010908191954.C11329@athlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.20i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sep 08, 2001 10:30 -0700, Linus Torvalds wrote: > I'll merge the blkdev in pagecache very early in 2.5.x, but I'm a bit > nervous about merging it in 2.4.x. > > That said, if you'll give a description of how you fixed the aliasing > issues etc, maybe I'd be less nervous. Putting it in the page cache is > 100% the right thing to do, so in theory I'd really like to merge it > earlier rather than later, but... I think this may have bad interactions with the filesystems, which still use buffer cache for metadata. If the block devices move to page cache, so should the filesystems. For example, the "tune2fs" program will modify parts of the superblock from user space (fields that are read-only from the kernel, e.g. label, reserved blocks count, etc), because it knows that the data read/written on /dev/hda1 is coherent with that in the kernel for the filesystem on /dev/hda1. The same is true with e2fsck - the metadata should be kept coherent from user-space and kernel-space or bad things happen. Cheers, Andreas -- Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto, \ would they cancel out, leaving him still hungry?" http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert