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fsnotify: Remove special handling of mark destruction on group shutdown 

Currently we queue all marks for destruction on group shutdown and then
destroy them from fsnotify_destroy_group() instead from a worker thread
which is the usual path. However worker can already be processing some
list of marks to destroy so this does not make 100% all marks are really
destroyed by the time group is shut down. This isn't a big problem as
each mark holds group reference and thus group stays partially alive
until all marks are really freed but there's no point in complicating
our lives - just wait for the delayed work to be finished instead.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2016-12-21 14:48:18 +01:00
parent 6b3f05d24d
commit f09b04a03e
3 changed files with 12 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/notify/fsnotify.h
View File

@ -36,10 +36,8 @@ static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
}
/* prepare for freeing all marks associated with given group */
extern void fsnotify_detach_group_marks(struct fsnotify_group *group);
/*
* wait for fsnotify_mark_srcu period to end and free all marks in destroy_list
*/
extern void fsnotify_mark_destroy_list(void);
/* Wait until all marks queued for destruction are destroyed */
extern void fsnotify_wait_marks_destroyed(void);
/*
* update the dentry->d_flags of all of inode's children to indicate if inode cares

10
fs/notify/group.c
View File

@ -66,14 +66,16 @@ void fsnotify_destroy_group(struct fsnotify_group *group)
*/
fsnotify_group_stop_queueing(group);
/* clear all inode marks for this group, attach them to destroy_list */
/* Clear all marks for this group and queue them for destruction */
fsnotify_detach_group_marks(group);
/*
* Wait for fsnotify_mark_srcu period to end and free all marks in
* destroy_list
* Wait until all marks get really destroyed. We could actually destroy
* them ourselves instead of waiting for worker to do it, however that
* would be racy as worker can already be processing some marks before
* we even entered fsnotify_destroy_group().
*/
fsnotify_mark_destroy_list();
fsnotify_wait_marks_destroyed();
/*
* Since we have waited for fsnotify_mark_srcu in

7
fs/notify/mark.c
View File

@ -703,7 +703,7 @@ void fsnotify_init_mark(struct fsnotify_mark *mark,
* Destroy all marks in destroy_list, waits for SRCU period to finish before
* actually freeing marks.
*/
void fsnotify_mark_destroy_list(void)
static void fsnotify_mark_destroy_workfn(struct work_struct *work)
{
struct fsnotify_mark *mark, *next;
struct list_head private_destroy_list;
@ -721,7 +721,8 @@ void fsnotify_mark_destroy_list(void)
}
}
static void fsnotify_mark_destroy_workfn(struct work_struct *work)
/* Wait for all marks queued for destruction to be actually destroyed */
void fsnotify_wait_marks_destroyed(void)
{
fsnotify_mark_destroy_list();
flush_delayed_work(&reaper_work);
}