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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7C49C25B6E for ; Tue, 24 Oct 2023 20:19:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344320AbjJXUTY (ORCPT ); Tue, 24 Oct 2023 16:19:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343752AbjJXUTW (ORCPT ); Tue, 24 Oct 2023 16:19:22 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A70CD7A; Tue, 24 Oct 2023 13:19:21 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63283C433C7; Tue, 24 Oct 2023 20:19:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698178760; bh=/jXqC7vbvPCmettO3DV3ntCzZ6lqFawlTkTOPw+dpkg=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=cNFVEaHU/JSGFWmYYSgGbEUwcbU6E57XzHmF6PqxxLbNxe6qOiw0skHlgT2FAmt4E pi7vTvmXtMoxa+QN5NsjIdLL7cod+koC+MMTHlEpmPJUMjUC2aCFbd6V/QPJYLMFs8 HeGKpzhI7MJVwlt6Q6WqHDPcW/boyVT98qJk/U++wdAZeq1FkdpLsbC5n4rWR+02Sm 4Zz7+vBjkN7QlHu9uefsCd9OegvQAC62mZ6Y5yTZ4a6WJMK/LSFJN+jV5JHIiYtpq6 BfJsXaU5B0axY0tFkCUNbOVQ0CdE3cC5UHu6WxcIlleK2U9pGJasSUCR6GhHkowEoo o0g7zaVbON3Zw== Message-ID: <62828738f237c3d972f71f8da150b3366eb3e1a0.camel@kernel.org> Subject: Re: [PATCH RFC 2/9] timekeeping: new interfaces for multigrain timestamp handing From: Jeff Layton To: Linus Torvalds Cc: Dave Chinner , Kent Overstreet , Christian Brauner , Alexander Viro , John Stultz , Thomas Gleixner , Stephen Boyd , Chandan Babu R , "Darrick J. Wong" , Theodore Ts'o , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , Amir Goldstein , Jan Kara , David Howells , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org Date: Tue, 24 Oct 2023 16:19:17 -0400 In-Reply-To: References: <5f96e69d438ab96099bb67d16b77583c99911caa.camel@kernel.org> <20231019-fluor-skifahren-ec74ceb6c63e@brauner> <0a1a847af4372e62000b259e992850527f587205.camel@kernel.org> <61b32a4093948ae1ae8603688793f07de764430f.camel@kernel.org> <2c74660bc44557dba8391758535e4012cbea3724.camel@kernel.org> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2023-10-24 at 09:40 -1000, Linus Torvalds wrote: > On Tue, 24 Oct 2023 at 09:07, Jeff Layton wrote: > >=20 > > The new flag idea is a good one. The catch though is that there are no > > readers of i_version in-kernel other than NFSD and IMA, so there would > > be no in-kernel users of I_VERSION_QUERIED_STRICT. >=20 > I actually see that as an absolute positive. >=20 > I think we should *conceptually* do those two flags, but then realize > that there are no users of the STRICT version, and just skip it. >=20 > So practically speaking, we'd end up with just a weaker version of > I_VERSION_QUERIED that is that "I don't care about atime" case. >=20 To be clear, this is not kernel-wide behavior. Most filesystems already don't bump their i_version on atime updates. XFS is the only one that does. ext4 used to do that too, but we fixed that several months ago. I did try to just fix XFS in the same way, but the patch was NAK'ed. > I really can't find any use that would *want* to see i_version updates > for any atime updates. Ever. >=20 > We may have had historical user interfaces for i_version, but I can't > find any currently. >=20 > But to be very very clear: I've only done some random grepping, and I > may have missed something. I'm not dismissing Dave's worries, and he > may well be entirely correct. >=20 > Somebody would need to do a much more careful check than my "I can't > find anything". Exactly. I'm not really an XFS guy, so I took those folks at their word that this was behavior that they just can't trivially change. None of the in-kernel callers that look at i_version want it to be incremented on atime-onlt updates, however. So IIRC, the objection was due to offline repair/analysis tools that depend this the value being incremented in a specific way. --=20 Jeff Layton