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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E62A6C25B70 for ; Tue, 24 Oct 2023 20:19:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 53BCD6B02E6; Tue, 24 Oct 2023 16:19:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4ED2A6B02E7; Tue, 24 Oct 2023 16:19:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3B35C6B02E8; Tue, 24 Oct 2023 16:19:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 2C4A06B02E6 for ; Tue, 24 Oct 2023 16:19:24 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 04832160181 for ; Tue, 24 Oct 2023 20:19:23 +0000 (UTC) X-FDA: 81381469848.23.D42CE10 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf23.hostedemail.com (Postfix) with ESMTP id 47E8F14001E for ; Tue, 24 Oct 2023 20:19:22 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=cNFVEaHU; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf23.hostedemail.com: domain of jlayton@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=jlayton@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1698178762; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/jXqC7vbvPCmettO3DV3ntCzZ6lqFawlTkTOPw+dpkg=; b=4OMVU1nAcmyTLCCOCeDgSEJ8Ug2hAgOVqlUxOHssCvUFT9+mXvoHnxC+COL8+H2gTOQGB/ AG39zEl+e5j33nV8Q6PUy02w8z6y8Z0o3KN5thFeVavdNAEYwmG7TdMvMzWFaqKoAhajiO khVC4YzEpx//I9axNH7ZBEPWG0Zw2bo= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=cNFVEaHU; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf23.hostedemail.com: domain of jlayton@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=jlayton@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1698178762; a=rsa-sha256; cv=none; b=UvO4DXE5YMwG9etN3pUUZIrHgbaT5S/sj4O1cIuiF8ptoqanf2yL/ZkBix6uDOI+Yr6PFG Hv1Ya0DKhW0idOhl+FB4Z37nNKh6O0kHhBmIVMBQKzjrmUxgN0eHTNmixIAEAdBy5DF4+E DFc1WKs+kkrO1Mr1446GOagEeZaoAio= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 4BF5B62C66; Tue, 24 Oct 2023 20:19:21 +0000 (UTC) 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 X-Rspamd-Queue-Id: 47E8F14001E X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: hhgyqf1t679jharkorrh3wcwpdudmexi X-HE-Tag: 1698178762-294674 X-HE-Meta: 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 GsgI68yA UuFYHsHwi9kaEDBtFhwfw8lA96OwQhmWdBOESATFVPfCGVIkYQerAQha2gSsyELhPdyLcuiWOZDnJYRi6ceB9/hw3XY9balgYEhMHYUpC1s6tdqwDCScdvQMF3y/N7jqdvITpBmVE2NQVv0sq3MKfqFTXMbrbMMa34u/tRW2l/ZwwiMh/8acnslwhVi4jRkqR4Tyorsc1lRb8LR5LZ1Lz45zABRgOzZOvzaIvCuWtEpq/1KVu7nEgp0y5yZvuRlgiPXqZ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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