Return-Path: linux-nfs-owner@vger.kernel.org Received: from li9-11.members.linode.com ([67.18.176.11]:60436 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757199Ab2ENR60 (ORCPT ); Mon, 14 May 2012 13:58:26 -0400 Date: Mon, 14 May 2012 13:58:22 -0400 From: "Ted Ts'o" To: Andreas Dilger Cc: "J. Bruce Fields" , "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: <20120514175822.GC1439@thunk.org> References: <20120514140618.GA29902@fieldses.org> <9124E59E-2479-4C32-A528-3237B48DEC01@dilger.ca> <20120514152334.GB29902@fieldses.org> <14B38D68-FAE4-444A-BCD9-7EBF7E1BBFE1@dilger.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <14B38D68-FAE4-444A-BCD9-7EBF7E1BBFE1@dilger.ca> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, May 14, 2012 at 11:27:42AM -0600, Andreas Dilger wrote: > > And if it at all possible I'd rather have it be something that Just > > Works rather than something that requires extra configuration. > > Sure, but this is only useful for NFSv4, but costs everyone using > ext4 continuous overhead, so it isn't a clear-cut case to enable > the version just on the thought that NFS might one day be used on > any particular filesystem. It's not a matter of "NFSv4 might one day be used"; if we don't turn on i_version updates until the file system is actually exported via NFSv4, there would be no deleterious effects. I always thought that was going to be the plan; that there would be some flag that would be set in struct super_block when the file system was exported that would enable i_version updates. That way we satisfy the "no extra configuration" needed requirement, which I agree is ideal, but we also don't waste any CPU overhead if the file system is not exported via NFSv4. I tried to implement anything along these lines because I don't care enough, and I don't use NFSv4 personally.... - Ted