From patchwork Mon Jan 25 20:37:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 12044305 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=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 46997C433E6 for ; Mon, 25 Jan 2021 20:39:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 19E692255F for ; Mon, 25 Jan 2021 20:39:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732285AbhAYUjE (ORCPT ); Mon, 25 Jan 2021 15:39:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:46054 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732362AbhAYUik (ORCPT ); Mon, 25 Jan 2021 15:38:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 91CB422583; Mon, 25 Jan 2021 20:37:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611607079; bh=IOywRg3GDIp5qw973MK7y5yXs1Lb3QGx/m0aTLci+8U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kUUf1umrvsvzEnHLD/If2qEqPV3xkaCUiDrTJ27zAd114SH+48jmUsmGHzymQiiXm ukYaLN4oVDgPPO2RweaQBFYPjRzT/IFsXvtbmxVSPt4QQAbKfuStOiGhS9yVa3U4rR Udf4CdHMI6/nsXQf5exMGG1+ALo8HK4qITS6Ff4w6XQWnxPdslzFuICvzbZR9JQN14 jnUbHZDX4Ay9LbWSV9cEHsT3Q9gk4IWCmhjICJ4qEWjw079ITpOOhImXmLDAY3tUHq A5AlmoRGyqwzmoupzoeBhrtVNpcRAU63qarMfz9TCy1rnthYFYQAEAR90uxHBqqDR6 k6NxIuWuduJiQ== From: Eric Biggers To: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, Jan Kara , Christoph Hellwig Subject: [PATCH 4.14 3/3] fs: fix lazytime expiration handling in __writeback_single_inode() Date: Mon, 25 Jan 2021 12:37:44 -0800 Message-Id: <20210125203744.325479-4-ebiggers@kernel.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210125203744.325479-1-ebiggers@kernel.org> References: <20210125203744.325479-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Eric Biggers commit 1e249cb5b7fc09ff216aa5a12f6c302e434e88f9 upstream. When lazytime is enabled and an inode is being written due to its in-memory updated timestamps having expired, either due to a sync() or syncfs() system call or due to dirtytime_expire_interval having elapsed, the VFS needs to inform the filesystem so that the filesystem can copy the inode's timestamps out to the on-disk data structures. This is done by __writeback_single_inode() calling mark_inode_dirty_sync(), which then calls ->dirty_inode(I_DIRTY_SYNC). However, this occurs after __writeback_single_inode() has already cleared the dirty flags from ->i_state. This causes two bugs: - mark_inode_dirty_sync() redirties the inode, causing it to remain dirty. This wastefully causes the inode to be written twice. But more importantly, it breaks cases where sync_filesystem() is expected to clean dirty inodes. This includes the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl (as reported at https://lore.kernel.org/r/20200306004555.GB225345@gmail.com), as well as possibly filesystem freezing (freeze_super()). - Since ->i_state doesn't contain I_DIRTY_TIME when ->dirty_inode() is called from __writeback_single_inode() for lazytime expiration, xfs_fs_dirty_inode() ignores the notification. (XFS only cares about lazytime expirations, and it assumes that i_state will contain I_DIRTY_TIME during those.) Therefore, lazy timestamps aren't persisted by sync(), syncfs(), or dirtytime_expire_interval on XFS. Fix this by moving the call to mark_inode_dirty_sync() to earlier in __writeback_single_inode(), before the dirty flags are cleared from i_state. This makes filesystems be properly notified of the timestamp expiration, and it avoids incorrectly redirtying the inode. This fixes xfstest generic/580 (which tests FS_IOC_REMOVE_ENCRYPTION_KEY) when run on ext4 or f2fs with lazytime enabled. It also fixes the new lazytime xfstest I've proposed, which reproduces the above-mentioned XFS bug (https://lore.kernel.org/r/20210105005818.92978-1-ebiggers@kernel.org). Alternatively, we could call ->dirty_inode(I_DIRTY_SYNC) directly. But due to the introduction of I_SYNC_QUEUED, mark_inode_dirty_sync() is the right thing to do because mark_inode_dirty_sync() now knows not to move the inode to a writeback list if it is currently queued for sync. Fixes: 0ae45f63d4ef ("vfs: add support for a lazytime mount option") Cc: stable@vger.kernel.org Depends-on: 5afced3bf281 ("writeback: Avoid skipping inode writeback") Link: https://lore.kernel.org/r/20210112190253.64307-2-ebiggers@kernel.org Suggested-by: Jan Kara Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Eric Biggers Signed-off-by: Jan Kara --- fs/fs-writeback.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index d6c05e5bdacb8..384f95e1936dd 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1390,21 +1390,25 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) } /* - * Some filesystems may redirty the inode during the writeback - * due to delalloc, clear dirty metadata flags right before - * write_inode() + * If the inode has dirty timestamps and we need to write them, call + * mark_inode_dirty_sync() to notify the filesystem about it and to + * change I_DIRTY_TIME into I_DIRTY_SYNC. */ - spin_lock(&inode->i_lock); - - dirty = inode->i_state & I_DIRTY; if ((inode->i_state & I_DIRTY_TIME) && - ((dirty & I_DIRTY_INODE) || - wbc->sync_mode == WB_SYNC_ALL || wbc->for_sync || + (wbc->sync_mode == WB_SYNC_ALL || wbc->for_sync || time_after(jiffies, inode->dirtied_time_when + dirtytime_expire_interval * HZ))) { - dirty |= I_DIRTY_TIME; trace_writeback_lazytime(inode); + mark_inode_dirty_sync(inode); } + + /* + * Some filesystems may redirty the inode during the writeback + * due to delalloc, clear dirty metadata flags right before + * write_inode() + */ + spin_lock(&inode->i_lock); + dirty = inode->i_state & I_DIRTY; inode->i_state &= ~dirty; /* @@ -1425,8 +1429,6 @@ __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); /* Don't write the inode if only I_DIRTY_PAGES was set */ if (dirty & ~I_DIRTY_PAGES) { int err = write_inode(inode, wbc);