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=-7.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 BC723C10DCE for ; Wed, 11 Mar 2020 03:20:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E5ED222C4 for ; Wed, 11 Mar 2020 03:20:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583896812; bh=B7xgBQEUb/r+AEoKXzPSxZbf08c/Z+iCpPzEuSoE/F8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=egPLxNSaRdjaXiXS131pobDDtGEUG5mWgRrED7ivoQzwL+Cknnw5gArn0FTHZk0AU szJMZI40yIAtvG8jo03Q2/xct4iHVsz39Me1zd8lM9P4VwO9hcSOvty/HfPu++h3gl +XC0xoCUQSdEbaPqMq95984/qWchvWkdib9g71lM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727648AbgCKDUL (ORCPT ); Tue, 10 Mar 2020 23:20:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:53606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727307AbgCKDUL (ORCPT ); Tue, 10 Mar 2020 23:20:11 -0400 Received: from gmail.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B946F21927; Wed, 11 Mar 2020 03:20:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583896810; bh=B7xgBQEUb/r+AEoKXzPSxZbf08c/Z+iCpPzEuSoE/F8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=z6Mh5X93gscC3R5GBKJqrSbWul9Y2vkMh+xBH9F34D44D8YlNg+pXwc0LaVkf1rjn tywYLH1vl5MiQyJdfJXVSlWtd7GnAL/2lT4PPMK5zccVN8blmwdUm4mobS8hLJxqJy use+h+rMW+C8MRrzdDS/MdS017PzI8vhdfcHoDTg= Date: Tue, 10 Mar 2020 20:20:09 -0700 From: Eric Biggers To: Theodore Ts'o 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: <20200311032009.GC46757@gmail.com> References: <20200306004555.GB225345@gmail.com> <20200307020043.60118-1-tytso@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200307020043.60118-1-tytso@mit.edu> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Fri, Mar 06, 2020 at 09:00:43PM -0500, Theodore Ts'o wrote: > In the case that an inode has dirty timestamp for longer than the > lazytime expiration timeout (or if all such inodes are being flushed > out due to a sync or syncfs system call), we need to inform the file > system that the inode is dirty so that the inode's timestamps can be > copied out to the on-disk data structures. That's because if the file > system supports lazytime, it will have ignored the dirty_inode(inode, > I_DIRTY_TIME) notification when the timestamp was modified in memory.q > > Previously, this was accomplished by calling mark_inode_dirty_sync(), > but that has the unfortunate side effect of also putting the inode the > writeback list, and that's not necessary in this case, since we will > immediately call write_inode() afterwards. > > Eric Biggers noticed that this was causing problems for fscrypt after > the key was removed[1]. > > [1] https://lore.kernel.org/r/20200306004555.GB225345@gmail.com > > Reported-by: Eric Biggers > Signed-off-by: Theodore Ts'o > --- > fs/fs-writeback.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index 76ac9c7d32ec..32101349ba97 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -1504,8 +1504,9 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) > > spin_unlock(&inode->i_lock); > > - if (dirty & I_DIRTY_TIME) > - mark_inode_dirty_sync(inode); > + /* This was a lazytime expiration; we need to tell the file system */ > + if (dirty & I_DIRTY_TIME_EXPIRED && inode->i_sb->s_op->dirty_inode) > + inode->i_sb->s_op->dirty_inode(inode, I_DIRTY_TIME_EXPIRED); > /* Don't write the inode if only I_DIRTY_PAGES was set */ > if (dirty & ~I_DIRTY_PAGES) { > int err = write_inode(inode, wbc); > -- 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: static void xfs_fs_dirty_inode( struct inode *inode, int flag) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; struct xfs_trans *tp; if (!(inode->i_sb->s_flags & SB_LAZYTIME)) return; if (flag != I_DIRTY_SYNC || !(inode->i_state & I_DIRTY_TIME)) return; if (xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp)) return; xfs_ilock(ip, XFS_ILOCK_EXCL); xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); xfs_trans_log_inode(tp, ip, XFS_ILOG_TIMESTAMP); xfs_trans_commit(tp); } So flag=I_DIRTY_TIME_EXPIRED will be a no-op. Maybe you should be using I_DIRTY_SYNC instead? Or perhaps XFS should be checking for either I_DIRTY_TIME_EXPIRED or I_DIRTY_SYNC? - Eric