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=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 DD5D0C433E1 for ; Fri, 19 Jun 2020 02:20:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 934C520773 for ; Fri, 19 Jun 2020 02:20:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="nLr3ZJr5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729164AbgFSCUH (ORCPT ); Thu, 18 Jun 2020 22:20:07 -0400 Received: from fieldses.org ([173.255.197.46]:52028 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726517AbgFSCUG (ORCPT ); Thu, 18 Jun 2020 22:20:06 -0400 Received: by fieldses.org (Postfix, from userid 2815) id D77A814D8; Thu, 18 Jun 2020 22:20:05 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org D77A814D8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1592533205; bh=tPBUrS2dw2CNJJWnlKPuvieHEc3u/i6Wc5TU2ZESPC0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nLr3ZJr5/23V2Y5xzN5XfJB1JaO/LXjJBJuS+O9NwynuGAP6WZCnDsmGJwbFzBeu7 2+PmhFrjYHVYcPEwhS1oEEaCN089NnTXR8009D++ZJHgKiTSZrj3ZVUK7gfouBnZMZ /ZnVxmQsv1Fntbiv/ofG3OoLwKStJVESrWdppses= Date: Thu, 18 Jun 2020 22:20:05 -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: <20200619022005.GA25414@fieldses.org> References: <24692989-2ee0-3dcc-16d8-aa436114f5fb@sandeen.net> <20200617172456.GP11245@magnolia> <8f0df756-4f71-9d96-7a52-45bf51482556@sandeen.net> <20200617181816.GA18315@fieldses.org> <4cbb5cbe-feb4-2166-0634-29041a41a8dc@sandeen.net> <20200617184507.GB18315@fieldses.org> <20200618013026.ewnhvf64nb62k2yx@gabell> <20200618030539.GH2005@dread.disaster.area> <20200618034535.h5ho7pd4eilpbj3f@gabell> <20200618223948.GI2005@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200618223948.GI2005@dread.disaster.area> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Fri, Jun 19, 2020 at 08:39:48AM +1000, Dave Chinner wrote: > On Wed, Jun 17, 2020 at 11:45:35PM -0400, Masayoshi Mizuma wrote: > > Thank you for pointed it out. > > How about following change? I believe it works both xfs and btrfs... > > > > diff --git a/fs/super.c b/fs/super.c > > index b0a511bef4a0..42fc6334d384 100644 > > --- a/fs/super.c > > +++ b/fs/super.c > > @@ -973,6 +973,9 @@ int reconfigure_super(struct fs_context *fc) > > } > > } > > > > + if (sb->s_flags & SB_I_VERSION) > > + fc->sb_flags |= MS_I_VERSION; > > + > > WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) | > > (fc->sb_flags & fc->sb_flags_mask))); > > /* Needs to be ordered wrt mnt_is_readonly() */ > > This will prevent SB_I_VERSION from being turned off at all. That > will break existing filesystems that allow SB_I_VERSION to be turned > off on remount, such as ext4. > > The manipulations here need to be in the filesystem specific code; > we screwed this one up so badly there is no "one size fits all" > behaviour that we can implement in the generic code... 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. But looking back through Jeff's postings, I don't see him claiming that; e.g. in: https://lore.kernel.org/lkml/20171222120556.7435-1-jlayton@kernel.org/ https://lore.kernel.org/linux-nfs/20180109141059.25929-1-jlayton@kernel.org/ https://lore.kernel.org/linux-nfs/1517228795.5965.24.camel@redhat.com/ he reports comparing old iversion behavior to new iversion behavior, but not new iversion behavior to new noiversion behavior. --b.