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From: Eric Biggers <ebiggers@kernel.org>
To: linux-fsdevel@vger.kernel.org
Cc: linux-ext4@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-xfs@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>,
	Christoph Hellwig <hch@lst.de>
Subject: [PATCH 13/13] xfs: implement lazytime_expired
Date: Mon,  4 Jan 2021 16:54:52 -0800
Message-ID: <20210105005452.92521-14-ebiggers@kernel.org> (raw)
In-Reply-To: <20210105005452.92521-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

Implement the new ->lazytime_expired method to get notified of lazytime
timestamp expirations, instead of relying on ->dirty_inode(inode,
I_DIRTY_SYNC) which is potentially ambiguous.

This fixes a bug where XFS didn't write lazytime timestamps to disk upon
a sync(), or after 24 hours (dirtytime_expire_interval * 2).  This is
because it only wrote the timestamps if I_DIRTY_TIME was set in i_state.
But actually when an inode's timestamps expire without the inode being
marked I_DIRTY_SYNC first, then ->dirty_inode isn't called until
__writeback_single_inode() has already cleared I_DIRTY_TIME in i_state.

The new ->lazytime_expired method is unambiguous, so it removes any need
to check for I_DIRTY_TIME, which avoids this bug.

I've written an xfstest which reproduces this bug.

Fixes: c3b1b13190ae ("xfs: implement the lazytime mount option")
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/xfs/xfs_super.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 813be879a5e51..0b7623907b264 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -666,19 +666,13 @@ xfs_fs_destroy_inode(
 }
 
 static void
-xfs_fs_dirty_inode(
-	struct inode			*inode,
-	int				flag)
+xfs_fs_lazytime_expired(
+	struct inode			*inode)
 {
 	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);
@@ -1108,7 +1102,7 @@ xfs_fs_free_cached_objects(
 static const struct super_operations xfs_super_operations = {
 	.alloc_inode		= xfs_fs_alloc_inode,
 	.destroy_inode		= xfs_fs_destroy_inode,
-	.dirty_inode		= xfs_fs_dirty_inode,
+	.lazytime_expired	= xfs_fs_lazytime_expired,
 	.drop_inode		= xfs_fs_drop_inode,
 	.put_super		= xfs_fs_put_super,
 	.sync_fs		= xfs_fs_sync_fs,
-- 
2.30.0


      parent reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-05  0:54 [PATCH 00/13] lazytime fixes and cleanups Eric Biggers
2021-01-05  0:54 ` [PATCH 01/13] fs: avoid double-writing inodes on lazytime expiration Eric Biggers
2021-01-07 14:47   ` Jan Kara
2021-01-07 14:58     ` Matthew Wilcox
2021-01-07 21:46     ` Eric Biggers
2021-01-08  8:54       ` Christoph Hellwig
2021-01-08  9:01     ` Christoph Hellwig
2021-01-09 17:11       ` Eric Biggers
2021-01-05  0:54 ` [PATCH 02/13] gfs2: don't worry about I_DIRTY_TIME in gfs2_fsync() Eric Biggers
2021-01-08  8:54   ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 03/13] fs: only specify I_DIRTY_TIME when needed in generic_update_time() Eric Biggers
2021-01-08  8:57   ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 04/13] fat: only specify I_DIRTY_TIME when needed in fat_update_time() Eric Biggers
2021-01-07 13:13   ` Jan Kara
2021-01-07 19:10     ` Eric Biggers
2021-01-05  0:54 ` [PATCH 05/13] fs: don't call ->dirty_inode for lazytime timestamp updates Eric Biggers
2021-01-07 13:17   ` Jan Kara
2021-01-07 13:18     ` Jan Kara
2021-01-08  9:02   ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 06/13] fs: pass only I_DIRTY_INODE flags to ->dirty_inode Eric Biggers
2021-01-08  9:02   ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 07/13] fs: correctly document the inode dirty flags Eric Biggers
2021-01-08  9:03   ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 08/13] ext4: simplify i_state checks in __ext4_update_other_inode_time() Eric Biggers
2021-01-07 13:24   ` Jan Kara
2021-01-07 19:06     ` Eric Biggers
2021-01-05  0:54 ` [PATCH 09/13] fs: drop redundant checks from __writeback_single_inode() Eric Biggers
2021-01-08  9:12   ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 10/13] fs: clean up __mark_inode_dirty() a bit Eric Biggers
2021-01-08  9:10   ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 11/13] fs: add a lazytime_expired method Eric Biggers
2021-01-07 14:02   ` Jan Kara
2021-01-07 22:05     ` Eric Biggers
2021-01-08  9:14       ` Christoph Hellwig
2021-01-05  0:54 ` [PATCH 12/13] xfs: remove a stale comment from xfs_file_aio_write_checks() Eric Biggers
2021-01-08  9:15   ` Christoph Hellwig
2021-01-05  0:54 ` Eric Biggers [this message]

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