Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:35927 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932720Ab2ENXyf (ORCPT ); Mon, 14 May 2012 19:54:35 -0400 Date: Mon, 14 May 2012 19:54:32 -0400 From: "J. Bruce Fields" To: Andreas Dilger Cc: "Myklebust, Trond" , "Theodore Ts'o" , "linux-ext4@vger.kernel.org" , "linux-nfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" Subject: Re: [PATCH] ext4: turn on i_version updates by default Message-ID: <20120514235432.GA3199@fieldses.org> References: <20120514140618.GA29902@fieldses.org> <9124E59E-2479-4C32-A528-3237B48DEC01@dilger.ca> <1337036918.2522.32.camel@lade.trondhjem.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, May 14, 2012 at 05:33:04PM -0600, Andreas Dilger wrote: > I said as much in another reply - that once i_version is used on > a filesystem, it should be made "sticky" (i.e. permanently enabled > for that filesystem). However, until that time it shouldn't be > enabled just because it might one day be used. > > Even better than just blindly bumping the i_version on every change, > it would be better to have users of i_version (i.e. knfsd) flag the > inode with "needs i_version update" then read the version. When the > filesystem/VFS bumps i_version the next time it can clear this flag > and not update i_version again until after the next time i_version > is actually used. I really don't want to do anything more complicated than necessary. What would be the worst-case test for the extra inode dirtying, so we can see what the numbers actually are? --b.