From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0689FC433E0 for ; Sat, 20 Jun 2020 01:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D44F722D2C for ; Sat, 20 Jun 2020 01:56:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="T9/sZJMp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731599AbgFTB4e (ORCPT ); Fri, 19 Jun 2020 21:56:34 -0400 Received: from fieldses.org ([173.255.197.46]:41234 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731589AbgFTB4e (ORCPT ); Fri, 19 Jun 2020 21:56:34 -0400 Received: by fieldses.org (Postfix, from userid 2815) id C14F191D8; Fri, 19 Jun 2020 21:56:33 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org C14F191D8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1592618193; bh=px2fxrVRGaefarQd+BFyouZ0r8UsW3DJrqCLsAmy3qs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=T9/sZJMpMOgd+/TkpaAoBFfhJJXx0Rt3kQv+PaHGiCUpVIwWIfRwp6CtiEPMpERoB apwrhYqnopPoBS5TNsHZUdB6O6Kj4KWRBuE43RfpCw5geLcE6VwwarEHXeY4pRTXrx 3AErIh9dL/mYCpaZppI/hiDk67oG4cNXJLjt+f2E= Date: Fri, 19 Jun 2020 21:56:33 -0400 From: "J. Bruce Fields" To: Dave Chinner Cc: Masayoshi Mizuma , Eric Sandeen , "Darrick J. Wong" , Christoph Hellwig , Theodore Ts'o , Andreas Dilger , Alexander Viro , Masayoshi Mizuma , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs , jlayton@redhat.com Subject: Re: [PATCH] fs: i_version mntopt gets visible through /proc/mounts Message-ID: <20200620015633.GA1516@fieldses.org> References: <20200618013026.ewnhvf64nb62k2yx@gabell> <20200618030539.GH2005@dread.disaster.area> <20200618034535.h5ho7pd4eilpbj3f@gabell> <20200618223948.GI2005@dread.disaster.area> <20200619022005.GA25414@fieldses.org> <20200619024455.GN2005@dread.disaster.area> <20200619204033.GB1564@fieldses.org> <20200619221044.GO2005@dread.disaster.area> <20200619222843.GB2650@fieldses.org> <20200620014957.GQ2005@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200620014957.GQ2005@dread.disaster.area> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sat, Jun 20, 2020 at 11:49:57AM +1000, Dave Chinner wrote: > On Fri, Jun 19, 2020 at 06:28:43PM -0400, J. Bruce Fields wrote: > > On Sat, Jun 20, 2020 at 08:10:44AM +1000, Dave Chinner wrote: > > > On Fri, Jun 19, 2020 at 04:40:33PM -0400, J. Bruce Fields wrote: > > > > On Fri, Jun 19, 2020 at 12:44:55PM +1000, Dave Chinner wrote: > > > > > On Thu, Jun 18, 2020 at 10:20:05PM -0400, J. Bruce Fields wrote: > > > > > > My memory was that after Jeff Layton's i_version patches, there wasn't > > > > > > really a significant performance hit any more, so the ability to turn it > > > > > > off is no longer useful. > > > > > > > > > > Yes, I completely agree with you here. However, with some > > > > > filesystems allowing it to be turned off, we can't just wave our > > > > > hands and force enable the option. Those filesystems - if the > > > > > maintainers chose to always enable iversion - will have to go > > > > > through a mount option deprecation period before permanently > > > > > enabling it. > > > > > > > > I don't understand why. > > > > > > > > The filesystem can continue to let people set iversion or noiversion as > > > > they like, while under the covers behaving as if iversion is always set. > > > > I can't see how that would break any application. (Or even how an > > > > application would be able to detect that the filesystem was doing this.) > > > > > > It doesn't break functionality, but it affects performance. > > > > I thought you just agreed above that any performance hit was not > > "significant". > > Yes, but that's just /my opinion/. > > However, other people have different opinions on this matter (and we > know that from the people who considered XFS v4 -> v5 going slower > because iversion a major regression), and so we must acknowledge > those opinions even if we don't agree with them. Do you have any of those reports handy? Were there numbers? --b.