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Date: Wed, 3 Aug 2022 12:53:39 +0200
From: Lukas Czerner <lczerner@...hat.com>
To: linux-ext4@...r.kernel.org
Cc: jlayton@...nel.org, tytso@....edu, linux-fsdevel@...r.kernel.org,
Dave Chinner <david@...morbit.com>,
Christoph Hellwig <hch@...radead.org>, Jan Kara <jack@...e.cz>
Subject: [PATCH v2 2/3] fs: record I_DIRTY_TIME even if inode already has I_DIRTY_INODE
Currently the I_DIRTY_TIME will never get set if the inode already has
I_DIRTY_INODE with assumption that it supersedes I_DIRTY_TIME. That's
true, however ext4 will only update the on-disk inode in
->dirty_inode(), not on actual writeback. As a result if the inode
already has I_DIRTY_INODE state by the time we get to
__mark_inode_dirty() only with I_DIRTY_TIME, the time was already filled
into on-disk inode and will not get updated until the next I_DIRTY_INODE
update, which might never come if we crash or get a power failure.
The problem can be reproduced on ext4 by running xfstest generic/622
with -o iversion mount option.
Fix it by allowing I_DIRTY_TIME to be set even if the inode already has
I_DIRTY_INODE. Also make sure that the case is properly handled in
writeback_single_inode() as well. Additionally changes in
xfs_fs_dirty_inode() was made to accommodate for I_DIRTY_TIME in flag.
Thanks Jan Kara for suggestions on how to make this work properly.
Cc: Dave Chinner <david@...morbit.com>
Cc: Christoph Hellwig <hch@...radead.org>
Signed-off-by: Lukas Czerner <lczerner@...hat.com>
Suggested-by: Jan Kara <jack@...e.cz>
---
v2: Reworked according to suggestions from Jan
fs/fs-writeback.c | 34 ++++++++++++++++++++++------------
fs/xfs/xfs_super.c | 3 ++-
include/linux/fs.h | 6 +++---
3 files changed, 27 insertions(+), 16 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 05221366a16d..638dbf143727 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1718,9 +1718,14 @@ static int writeback_single_inode(struct inode *inode,
*/
if (!(inode->i_state & I_DIRTY_ALL))
inode_cgwb_move_to_attached(inode, wb);
- else if (!(inode->i_state & I_SYNC_QUEUED) &&
- (inode->i_state & I_DIRTY))
- redirty_tail_locked(inode, wb);
+ else if (!(inode->i_state & I_SYNC_QUEUED)) {
+ if ((inode->i_state & I_DIRTY))
+ redirty_tail_locked(inode, wb);
+ else if (inode->i_state & I_DIRTY_TIME) {
+ inode->dirtied_when = jiffies;
+ inode_io_list_move_locked(inode, wb, &wb->b_dirty_time);
+ }
+ }
spin_unlock(&wb->list_lock);
inode_sync_complete(inode);
@@ -2369,6 +2374,17 @@ void __mark_inode_dirty(struct inode *inode, int flags)
trace_writeback_mark_inode_dirty(inode, flags);
if (flags & I_DIRTY_INODE) {
+
+ /* Inode timestamp update will piggback on this dirtying */
+ if (inode->i_state & I_DIRTY_TIME) {
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & I_DIRTY_TIME) {
+ inode->i_state &= ~I_DIRTY_TIME;
+ flags |= I_DIRTY_TIME;
+ }
+ spin_unlock(&inode->i_lock);
+ }
+
/*
* Notify the filesystem about the inode being dirtied, so that
* (if needed) it can update on-disk fields and journal the
@@ -2378,7 +2394,8 @@ void __mark_inode_dirty(struct inode *inode, int flags)
*/
trace_writeback_dirty_inode_start(inode, flags);
if (sb->s_op->dirty_inode)
- sb->s_op->dirty_inode(inode, flags & I_DIRTY_INODE);
+ sb->s_op->dirty_inode(inode,
+ flags & (I_DIRTY_INODE | I_DIRTY_TIME));
trace_writeback_dirty_inode(inode, flags);
/* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
@@ -2399,21 +2416,15 @@ void __mark_inode_dirty(struct inode *inode, int flags)
*/
smp_mb();
- if (((inode->i_state & flags) == flags) ||
- (dirtytime && (inode->i_state & I_DIRTY_INODE)))
+ if ((inode->i_state & flags) == flags)
return;
spin_lock(&inode->i_lock);
- if (dirtytime && (inode->i_state & I_DIRTY_INODE))
- goto out_unlock_inode;
if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY;
inode_attach_wb(inode, NULL);
- /* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
- if (flags & I_DIRTY_INODE)
- inode->i_state &= ~I_DIRTY_TIME;
inode->i_state |= flags;
/*
@@ -2486,7 +2497,6 @@ void __mark_inode_dirty(struct inode *inode, int flags)
out_unlock:
if (wb)
spin_unlock(&wb->list_lock);
-out_unlock_inode:
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(__mark_inode_dirty);
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index aa977c7ea370..cff05a4771b5 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -658,7 +658,8 @@ xfs_fs_dirty_inode(
if (!(inode->i_sb->s_flags & SB_LAZYTIME))
return;
- if (flag != I_DIRTY_SYNC || !(inode->i_state & I_DIRTY_TIME))
+ if ((flag & ~I_DIRTY_TIME) != I_DIRTY_SYNC ||
+ !((inode->i_state | flag) & I_DIRTY_TIME))
return;
if (xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9ad5e3520fae..2243797badf2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2245,9 +2245,9 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
* lazytime mount option is enabled. We keep track of this
* separately from I_DIRTY_SYNC in order to implement
* lazytime. This gets cleared if I_DIRTY_INODE
- * (I_DIRTY_SYNC and/or I_DIRTY_DATASYNC) gets set. I.e.
- * either I_DIRTY_TIME *or* I_DIRTY_INODE can be set in
- * i_state, but not both. I_DIRTY_PAGES may still be set.
+ * (I_DIRTY_SYNC and/or I_DIRTY_DATASYNC) gets set. But
+ * I_DIRTY_TIME can still be set if I_DIRTY_SYNC is already
+ * in place.
* I_NEW Serves as both a mutex and completion notification.
* New inodes set I_NEW. If two processes both create
* the same inode, one of them will release its inode and
--
2.37.1
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