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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B7973C18E5A for ; Wed, 11 Mar 2020 12:58:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99CB82146E for ; Wed, 11 Mar 2020 12:58:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729400AbgCKM6D (ORCPT ); Wed, 11 Mar 2020 08:58:03 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:40659 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729331AbgCKM6C (ORCPT ); Wed, 11 Mar 2020 08:58:02 -0400 Received: from callcc.thunk.org (pool-72-93-95-157.bstnma.fios.verizon.net [72.93.95.157]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 02BCvnk4017660 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 11 Mar 2020 08:57:49 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 3D70A42045B; Wed, 11 Mar 2020 08:57:49 -0400 (EDT) Date: Wed, 11 Mar 2020 08:57:49 -0400 From: "Theodore Y. Ts'o" To: Eric Biggers Cc: Linux Filesystem Development List , Ext4 Developers List , linux-f2fs-devel@lists.sourceforge.net Subject: Re: [PATCH] writeback: avoid double-writing the inode on a lazytime expiration Message-ID: <20200311125749.GA7159@mit.edu> References: <20200306004555.GB225345@gmail.com> <20200307020043.60118-1-tytso@mit.edu> <20200311032009.GC46757@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200311032009.GC46757@gmail.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Mar 10, 2020 at 08:20:09PM -0700, Eric Biggers wrote: > Thanks Ted! This fixes the fscrypt test failure. > > However, are you sure this works correctly on all filesystems? I'm not sure > about XFS. XFS only implements ->dirty_inode(), not ->write_inode(), and in its > ->dirty_inode() it does: ... > if (flag != I_DIRTY_SYNC || !(inode->i_state & I_DIRTY_TIME)) > return; That's true, but when the timestamps were originally modified, dirty_inode() will be called with flag == I_DIRTY_TIME, which will *not* be a no-op; which is to say, XFS will force the timestamps to be updated on disk when the timestamps are first dirtied, because it doesn't support I_DIRTY_TIME. So I think we're fine. - Ted