linux/fs/notify
Amir Goldstein 172e422ffe fsnotify: clear PARENT_WATCHED flags lazily
In some setups directories can have many (usually negative) dentries.
Hence __fsnotify_update_child_dentry_flags() function can take a
significant amount of time. Since the bulk of this function happens
under inode->i_lock this causes a significant contention on the lock
when we remove the watch from the directory as the
__fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask()
races with __fsnotify_update_child_dentry_flags() calls from
__fsnotify_parent() happening on children. This can lead upto softlockup
reports reported by users.

Fix the problem by calling fsnotify_update_children_dentry_flags() to
set PARENT_WATCHED flags only when parent starts watching children.

When parent stops watching children, clear false positive PARENT_WATCHED
flags lazily in __fsnotify_parent() for each accessed child.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2024-06-05 09:52:38 +02:00
..
dnotify fsnotify: create a wrapper fsnotify_find_inode_mark() 2024-04-04 16:24:16 +02:00
fanotify Revert "fanotify: remove unneeded sub-zero check for unsigned value" 2024-05-20 12:43:58 -07:00
inotify fsnotify: create a wrapper fsnotify_find_inode_mark() 2024-04-04 16:24:16 +02:00
fdinfo.c fsnotify: Avoid -Wflex-array-member-not-at-end warning 2024-03-26 10:53:32 +01:00
fdinfo.h
fsnotify.c fsnotify: clear PARENT_WATCHED flags lazily 2024-06-05 09:52:38 +02:00
fsnotify.h fsnotify: clear PARENT_WATCHED flags lazily 2024-06-05 09:52:38 +02:00
group.c fsnotify: create helpers for group mark_mutex lock 2022-04-25 14:37:22 +02:00
Kconfig fs/notify: Remove "select SRCU" 2023-02-02 16:26:06 -08:00
Makefile
mark.c fsnotify: clear PARENT_WATCHED flags lazily 2024-06-05 09:52:38 +02:00
notification.c fsnotify: Pass group argument to free_event 2021-10-27 12:34:18 +02:00