From: Lukas Czerner lczerner@redhat.com
commit cbfecb927f429a6fa613d74b998496bd71e4438a upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Documentation/filesystems/vfs.rst | 3 +++ fs/fs-writeback.c | 37 +++++++++++++++++++++++++------------ fs/xfs/xfs_super.c | 10 ++++++++-- include/linux/fs.h | 9 +++++---- 4 files changed, 41 insertions(+), 18 deletions(-)
--- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -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 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1718,9 +1718,14 @@ static int writeback_single_inode(struct */ 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); @@ -2370,6 +2375,20 @@ void __mark_inode_dirty(struct inode *in
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 * inode. This is only needed when the inode itself is being @@ -2378,7 +2397,8 @@ void __mark_inode_dirty(struct inode *in */ 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 *in */ 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 *in out_unlock: if (wb) spin_unlock(&wb->list_lock); -out_unlock_inode: spin_unlock(&inode->i_lock); } EXPORT_SYMBOL(__mark_inode_dirty); --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -650,7 +650,7 @@ 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; @@ -658,7 +658,13 @@ 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)) --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2241,13 +2241,14 @@ static inline void kiocb_clone(struct ki * 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