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fs: record I_DIRTY_TIME even if inode already has I_DIRTY_INODE

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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@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220825100657.44217-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Lukas Czerner 2022-08-25 12:06:57 +02:00 committed by Theodore Ts'o
parent 50f094a558
commit cbfecb927f
4 changed files with 41 additions and 18 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
Documentation/filesystems/vfs.rst
View file

@ -274,6 +274,9 @@ or bottom half).
This is specifically for the inode itself being marked dirty,
not its data. If the update needs to be persisted by fdatasync(),
then I_DIRTY_DATASYNC will be set in the flags argument.
I_DIRTY_TIME will be set in the flags in case lazytime is enabled
and struct inode has times updated since the last ->dirty_inode
call.
``write_inode``
this method is called when the VFS needs to write an inode to

37
fs/fs-writeback.c
View file

@ -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 +2374,20 @@ 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.
* We tell ->dirty_inode callback that timestamps need to
* be updated by setting I_DIRTY_TIME in flags.
*/
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 +2397,8 @@ 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 +2419,15 @@ 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 +2500,6 @@ 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);

10
fs/xfs/xfs_super.c
View file

@ -653,7 +653,7 @@ xfs_fs_destroy_inode(
static void
xfs_fs_dirty_inode(
struct inode *inode,
int flag)
int flags)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
@ -661,7 +661,13 @@ xfs_fs_dirty_inode(
if (!(inode->i_sb->s_flags & SB_LAZYTIME))
return;
if (flag != I_DIRTY_SYNC || !(inode->i_state & I_DIRTY_TIME))
/*
* Only do the timestamp update if the inode is dirty (I_DIRTY_SYNC)
* and has dirty timestamp (I_DIRTY_TIME). I_DIRTY_TIME can be passed
* in flags possibly together with I_DIRTY_SYNC.
*/
if ((flags & ~I_DIRTY_TIME) != I_DIRTY_SYNC || !(flags & I_DIRTY_TIME))
return;
if (xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp))

9
include/linux/fs.h
View file

@ -2371,13 +2371,14 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
* don't have to write inode on fdatasync() when only
* e.g. the timestamps have changed.
* I_DIRTY_PAGES Inode has dirty pages. Inode itself may be clean.
* I_DIRTY_TIME The inode itself only has dirty timestamps, and the
* I_DIRTY_TIME The inode itself has dirty timestamps, and the
* 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 because writeback might already be in progress
* and we don't want to lose the time update
* 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