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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 22CA3C001B0 for ; Wed, 9 Aug 2023 17:44:28 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4RLcrC0kdhz3bX1 for ; Thu, 10 Aug 2023 03:44:27 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=parknet.co.jp (client-ip=210.171.160.6; helo=mail.parknet.co.jp; envelope-from=hirofumi@parknet.co.jp; receiver=lists.ozlabs.org) Received: from mail.parknet.co.jp (mail.parknet.co.jp [210.171.160.6]) by lists.ozlabs.org (Postfix) with ESMTP id 4RLcr46ST4z2ywt for ; Thu, 10 Aug 2023 03:44:20 +1000 (AEST) Received: from ibmpc.myhome.or.jp (server.parknet.ne.jp [210.171.168.39]) by mail.parknet.co.jp (Postfix) with ESMTPSA id B41832055FA5; Thu, 10 Aug 2023 02:44:18 +0900 (JST) Received: from devron.myhome.or.jp (foobar@devron.myhome.or.jp [192.168.0.3]) by ibmpc.myhome.or.jp (8.17.2/8.17.2/Debian-1) with ESMTPS id 379HiHKW223321 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 10 Aug 2023 02:44:18 +0900 Received: from devron.myhome.or.jp (foobar@localhost [127.0.0.1]) by devron.myhome.or.jp (8.17.2/8.17.2/Debian-1) with ESMTPS id 379HiHXo222009 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 10 Aug 2023 02:44:17 +0900 Received: (from hirofumi@localhost) by devron.myhome.or.jp (8.17.2/8.17.2/Submit) id 379HiApg221995; Thu, 10 Aug 2023 02:44:10 +0900 From: OGAWA Hirofumi To: Jeff Layton Subject: Re: [PATCH v7 05/13] fat: make fat_update_time get its own timestamp In-Reply-To: <2cb998ff14ace352a9dd553e82cfa0aa92ec09ce.camel@kernel.org> (Jeff Layton's message of "Wed, 09 Aug 2023 12:30:52 -0400") References: <20230807-mgctime-v7-0-d1dec143a704@kernel.org> <20230807-mgctime-v7-5-d1dec143a704@kernel.org> <87msz08vc7.fsf@mail.parknet.co.jp> <52bead1d6a33fec89944b96e2ec20d1ea8747a9a.camel@kernel.org> <878rak8hia.fsf@mail.parknet.co.jp> <20230809150041.452w7gucjmvjnvbg@quack3> <87v8do6y8q.fsf@mail.parknet.co.jp> <2cb998ff14ace352a9dd553e82cfa0aa92ec09ce.camel@kernel.org> Date: Thu, 10 Aug 2023 02:44:10 +0900 Message-ID: <87leek6rh1.fsf@mail.parknet.co.jp> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Latchesar Ionkov , Martin Brandenburg , Konstantin Komarov , Jan Kara , "Darrick J. Wong" , Dominique Martinet , Christian Schoenebeck , ecryptfs@vger.kernel.org, Yue Hu , David Howells , Chris Mason , Andreas Dilger , Hans de Goede , Marc Dionne , linux-xfs@vger.kernel.org, linux-afs@lists.infradead.org, linux-mtd@lists.infradead.org, Mike Marshall , Paulo Alcantara , linux-cifs@vger.kernel.org, Eric Van Hensbergen , Andreas Gruenbacher , Miklos Szeredi , Richard Weinberger , Mark Fasheh , linux-unionfs@vger.kernel.org, Hugh Dickins , Benjamin Coddington , Tyler Hicks , cluster-devel@redhat.com, coda@cs.cmu.edu, linux-mm@kvack.org, Ilya Dryomov , Iurii Zaikin , Namjae Jeon , Trond Myklebust , codalist@telemann.coda.cs.cmu.edu, Shyam Prasad N , Amir Goldstein , Kees Cook , ocfs2-devel@lists.linux.dev, Josef Bacik , Tom Talpey , Tejun Heo , Alexander Viro , Ronnie Sahlberg , David Sterba , Jaegeuk Kim , ceph-devel@vger.kernel.org, Xiubo Li , Jan Harkes , Christian Brauner , linux-ext4@vger.kernel.org, Theodore Ts'o , Joseph Qi , Greg Kroah-Hartman , v9fs@lists.linux.dev, ntfs3@lists.linux.dev, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Steve French , Sergey Senozhatsky , Luis Chamberlain , devel@lists.orangefs.org, Anna Schumaker , Jan Kara , Bob Peterson , linux-fsdevel@vger.kernel.org, Andrew Morton , Sungjong Seo , linux-erofs@lists.ozlabs.org, linux-nfs@vger.kernel.org, linux-btrfs@vger.kernel.org, Joel Becker Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" Jeff Layton writes: > On Thu, 2023-08-10 at 00:17 +0900, OGAWA Hirofumi wrote: >> Jan Kara writes: [...] > My mistake re: lazytime vs. relatime, but Jan is correct that this > shouldn't break anything there. Actually breaks ("break" means not corrupt fs, means it breaks lazytime optimization). It is just not always, but it should be always for some userspaces. > The logic in the revised generic_update_time is different because FAT is > is a bit strange. fat_update_time does extra truncation on the timestamp > that it is handed beyond what timestamp_truncate() does. > fat_truncate_time is called in many different places too, so I don't > feel comfortable making big changes to how that works. > > In the case of generic_update_time, it calls inode_update_timestamps > which returns a mask that shows which timestamps got updated. It then > marks the dirty_flags appropriately for what was actually changed. > > generic_update_time is used across many filesystems so we need to ensure > that it's OK to use even when multigrain timestamps are enabled. Those > haven't been enabled in FAT though, so I didn't bother, and left it to > dirtying the inode in the same way it was before, even though it now > fetches its own timestamps from the clock. Given the way that the mtime > and ctime are smooshed together in FAT, that seemed reasonable. > > Is there a particular case or flag combination you're concerned about > here? Yes. Because FAT has strange timestamps that different granularity on disk . This is why generic time truncation doesn't work for FAT. Well anyway, my concern is the only following part. In generic_update_time(), S_[CM]TIME are not the cause of I_DIRTY_SYNC if lazytime mode. - if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) + if ((flags & (S_VERSION|S_CTIME|S_MTIME)) && inode_maybe_inc_iversion(inode, false)) dirty_flags |= I_DIRTY_SYNC; If reverted this part to check only S_VERSION, I'm fine. Thanks. -- OGAWA Hirofumi