2 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2, or (at your option)
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; see the file COPYING. If not, write to
16 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
20 * fsnotify inode mark locking/lifetime/and refcnting
23 * The group->recnt and mark->refcnt tell how many "things" in the kernel
24 * currently are referencing the objects. Both kind of objects typically will
25 * live inside the kernel with a refcnt of 2, one for its creation and one for
26 * the reference a group and a mark hold to each other.
27 * If you are holding the appropriate locks, you can take a reference and the
28 * object itself is guaranteed to survive until the reference is dropped.
31 * There are 3 locks involved with fsnotify inode marks and they MUST be taken
32 * in order as follows:
36 * mark->connector->lock
38 * group->mark_mutex protects the marks_list anchored inside a given group and
39 * each mark is hooked via the g_list. It also protects the groups private
40 * data (i.e group limits).
42 * mark->lock protects the marks attributes like its masks and flags.
43 * Furthermore it protects the access to a reference of the group that the mark
44 * is assigned to as well as the access to a reference of the inode/vfsmount
45 * that is being watched by the mark.
47 * mark->connector->lock protects the list of marks anchored inside an
48 * inode / vfsmount and each mark is hooked via the i_list.
50 * A list of notification marks relating to inode / mnt is contained in
51 * fsnotify_mark_connector. That structure is alive as long as there are any
52 * marks in the list and is also protected by fsnotify_mark_srcu. A mark gets
53 * detached from fsnotify_mark_connector when last reference to the mark is
54 * dropped. Thus having mark reference is enough to protect mark->connector
55 * pointer and to make sure fsnotify_mark_connector cannot disappear. Also
56 * because we remove mark from g_list before dropping mark reference associated
57 * with that, any mark found through g_list is guaranteed to have
58 * mark->connector set until we drop group->mark_mutex.
61 * Inode marks survive between when they are added to an inode and when their
62 * refcnt==0. Marks are also protected by fsnotify_mark_srcu.
64 * The inode mark can be cleared for a number of different reasons including:
65 * - The inode is unlinked for the last time. (fsnotify_inode_remove)
66 * - The inode is being evicted from cache. (fsnotify_inode_delete)
67 * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes)
68 * - Something explicitly requests that it be removed. (fsnotify_destroy_mark)
69 * - The fsnotify_group associated with the mark is going away and all such marks
70 * need to be cleaned up. (fsnotify_clear_marks_by_group)
72 * This has the very interesting property of being able to run concurrently with
73 * any (or all) other directions.
77 #include <linux/init.h>
78 #include <linux/kernel.h>
79 #include <linux/kthread.h>
80 #include <linux/module.h>
81 #include <linux/mutex.h>
82 #include <linux/slab.h>
83 #include <linux/spinlock.h>
84 #include <linux/srcu.h>
86 #include <linux/atomic.h>
88 #include <linux/fsnotify_backend.h>
91 #define FSNOTIFY_REAPER_DELAY (1) /* 1 jiffy */
93 struct srcu_struct fsnotify_mark_srcu
;
94 struct kmem_cache
*fsnotify_mark_connector_cachep
;
96 static DEFINE_SPINLOCK(destroy_lock
);
97 static LIST_HEAD(destroy_list
);
98 static struct fsnotify_mark_connector
*connector_destroy_list
;
100 static void fsnotify_mark_destroy_workfn(struct work_struct
*work
);
101 static DECLARE_DELAYED_WORK(reaper_work
, fsnotify_mark_destroy_workfn
);
103 static void fsnotify_connector_destroy_workfn(struct work_struct
*work
);
104 static DECLARE_WORK(connector_reaper_work
, fsnotify_connector_destroy_workfn
);
106 void fsnotify_get_mark(struct fsnotify_mark
*mark
)
108 WARN_ON_ONCE(!atomic_read(&mark
->refcnt
));
109 atomic_inc(&mark
->refcnt
);
113 * Get mark reference when we found the mark via lockless traversal of object
114 * list. Mark can be already removed from the list by now and on its way to be
115 * destroyed once SRCU period ends.
117 static bool fsnotify_get_mark_safe(struct fsnotify_mark
*mark
)
119 return atomic_inc_not_zero(&mark
->refcnt
);
121 EXPORT_SYMBOL_GPL(fsnotify_put_mark
);
123 static void __fsnotify_recalc_mask(struct fsnotify_mark_connector
*conn
)
126 struct fsnotify_mark
*mark
;
128 assert_spin_locked(&conn
->lock
);
129 hlist_for_each_entry(mark
, &conn
->list
, obj_list
) {
130 if (mark
->flags
& FSNOTIFY_MARK_FLAG_ATTACHED
)
131 new_mask
|= mark
->mask
;
133 if (conn
->flags
& FSNOTIFY_OBJ_TYPE_INODE
)
134 conn
->inode
->i_fsnotify_mask
= new_mask
;
135 else if (conn
->flags
& FSNOTIFY_OBJ_TYPE_VFSMOUNT
)
136 real_mount(conn
->mnt
)->mnt_fsnotify_mask
= new_mask
;
140 * Calculate mask of events for a list of marks. The caller must make sure
141 * connector and connector->inode cannot disappear under us. Callers achieve
142 * this by holding a mark->lock or mark->group->mark_mutex for a mark on this
145 void fsnotify_recalc_mask(struct fsnotify_mark_connector
*conn
)
150 spin_lock(&conn
->lock
);
151 __fsnotify_recalc_mask(conn
);
152 spin_unlock(&conn
->lock
);
153 if (conn
->flags
& FSNOTIFY_OBJ_TYPE_INODE
)
154 __fsnotify_update_child_dentry_flags(conn
->inode
);
157 /* Free all connectors queued for freeing once SRCU period ends */
158 static void fsnotify_connector_destroy_workfn(struct work_struct
*work
)
160 struct fsnotify_mark_connector
*conn
, *free
;
162 spin_lock(&destroy_lock
);
163 conn
= connector_destroy_list
;
164 connector_destroy_list
= NULL
;
165 spin_unlock(&destroy_lock
);
167 synchronize_srcu(&fsnotify_mark_srcu
);
170 conn
= conn
->destroy_next
;
171 kmem_cache_free(fsnotify_mark_connector_cachep
, free
);
175 static struct inode
*fsnotify_detach_connector_from_object(
176 struct fsnotify_mark_connector
*conn
)
178 struct inode
*inode
= NULL
;
180 if (conn
->flags
& FSNOTIFY_OBJ_TYPE_INODE
) {
182 rcu_assign_pointer(inode
->i_fsnotify_marks
, NULL
);
183 inode
->i_fsnotify_mask
= 0;
185 conn
->flags
&= ~FSNOTIFY_OBJ_TYPE_INODE
;
186 } else if (conn
->flags
& FSNOTIFY_OBJ_TYPE_VFSMOUNT
) {
187 rcu_assign_pointer(real_mount(conn
->mnt
)->mnt_fsnotify_marks
,
189 real_mount(conn
->mnt
)->mnt_fsnotify_mask
= 0;
191 conn
->flags
&= ~FSNOTIFY_OBJ_TYPE_VFSMOUNT
;
197 static void fsnotify_final_mark_destroy(struct fsnotify_mark
*mark
)
199 struct fsnotify_group
*group
= mark
->group
;
201 if (WARN_ON_ONCE(!group
))
203 group
->ops
->free_mark(mark
);
204 fsnotify_put_group(group
);
207 void fsnotify_put_mark(struct fsnotify_mark
*mark
)
209 struct fsnotify_mark_connector
*conn
;
210 struct inode
*inode
= NULL
;
211 bool free_conn
= false;
213 /* Catch marks that were actually never attached to object */
214 if (!mark
->connector
) {
215 if (atomic_dec_and_test(&mark
->refcnt
))
216 fsnotify_final_mark_destroy(mark
);
221 * We have to be careful so that traversals of obj_list under lock can
222 * safely grab mark reference.
224 if (!atomic_dec_and_lock(&mark
->refcnt
, &mark
->connector
->lock
))
227 conn
= mark
->connector
;
228 hlist_del_init_rcu(&mark
->obj_list
);
229 if (hlist_empty(&conn
->list
)) {
230 inode
= fsnotify_detach_connector_from_object(conn
);
233 __fsnotify_recalc_mask(conn
);
235 mark
->connector
= NULL
;
236 spin_unlock(&conn
->lock
);
241 spin_lock(&destroy_lock
);
242 conn
->destroy_next
= connector_destroy_list
;
243 connector_destroy_list
= conn
;
244 spin_unlock(&destroy_lock
);
245 queue_work(system_unbound_wq
, &connector_reaper_work
);
248 * Note that we didn't update flags telling whether inode cares about
249 * what's happening with children. We update these flags from
250 * __fsnotify_parent() lazily when next event happens on one of our
253 spin_lock(&destroy_lock
);
254 list_add(&mark
->g_list
, &destroy_list
);
255 spin_unlock(&destroy_lock
);
256 queue_delayed_work(system_unbound_wq
, &reaper_work
,
257 FSNOTIFY_REAPER_DELAY
);
260 bool fsnotify_prepare_user_wait(struct fsnotify_iter_info
*iter_info
)
262 struct fsnotify_group
*group
;
264 if (WARN_ON_ONCE(!iter_info
->inode_mark
&& !iter_info
->vfsmount_mark
))
267 if (iter_info
->inode_mark
)
268 group
= iter_info
->inode_mark
->group
;
270 group
= iter_info
->vfsmount_mark
->group
;
273 * Since acquisition of mark reference is an atomic op as well, we can
274 * be sure this inc is seen before any effect of refcount increment.
276 atomic_inc(&group
->user_waits
);
278 if (iter_info
->inode_mark
) {
279 /* This can fail if mark is being removed */
280 if (!fsnotify_get_mark_safe(iter_info
->inode_mark
))
283 if (iter_info
->vfsmount_mark
) {
284 if (!fsnotify_get_mark_safe(iter_info
->vfsmount_mark
))
289 * Now that both marks are pinned by refcount in the inode / vfsmount
290 * lists, we can drop SRCU lock, and safely resume the list iteration
291 * once userspace returns.
293 srcu_read_unlock(&fsnotify_mark_srcu
, iter_info
->srcu_idx
);
297 if (iter_info
->inode_mark
)
298 fsnotify_put_mark(iter_info
->inode_mark
);
300 if (atomic_dec_and_test(&group
->user_waits
) && group
->shutdown
)
301 wake_up(&group
->notification_waitq
);
305 void fsnotify_finish_user_wait(struct fsnotify_iter_info
*iter_info
)
307 struct fsnotify_group
*group
= NULL
;
309 iter_info
->srcu_idx
= srcu_read_lock(&fsnotify_mark_srcu
);
310 if (iter_info
->inode_mark
) {
311 group
= iter_info
->inode_mark
->group
;
312 fsnotify_put_mark(iter_info
->inode_mark
);
314 if (iter_info
->vfsmount_mark
) {
315 group
= iter_info
->vfsmount_mark
->group
;
316 fsnotify_put_mark(iter_info
->vfsmount_mark
);
319 * We abuse notification_waitq on group shutdown for waiting for all
320 * marks pinned when waiting for userspace.
322 if (atomic_dec_and_test(&group
->user_waits
) && group
->shutdown
)
323 wake_up(&group
->notification_waitq
);
327 * Mark mark as detached, remove it from group list. Mark still stays in object
328 * list until its last reference is dropped. Note that we rely on mark being
329 * removed from group list before corresponding reference to it is dropped. In
330 * particular we rely on mark->connector being valid while we hold
331 * group->mark_mutex if we found the mark through g_list.
333 * Must be called with group->mark_mutex held. The caller must either hold
334 * reference to the mark or be protected by fsnotify_mark_srcu.
336 void fsnotify_detach_mark(struct fsnotify_mark
*mark
)
338 struct fsnotify_group
*group
= mark
->group
;
340 WARN_ON_ONCE(!mutex_is_locked(&group
->mark_mutex
));
341 WARN_ON_ONCE(!srcu_read_lock_held(&fsnotify_mark_srcu
) &&
342 atomic_read(&mark
->refcnt
) < 1 +
343 !!(mark
->flags
& FSNOTIFY_MARK_FLAG_ATTACHED
));
345 spin_lock(&mark
->lock
);
346 /* something else already called this function on this mark */
347 if (!(mark
->flags
& FSNOTIFY_MARK_FLAG_ATTACHED
)) {
348 spin_unlock(&mark
->lock
);
351 mark
->flags
&= ~FSNOTIFY_MARK_FLAG_ATTACHED
;
352 list_del_init(&mark
->g_list
);
353 spin_unlock(&mark
->lock
);
355 atomic_dec(&group
->num_marks
);
357 /* Drop mark reference acquired in fsnotify_add_mark_locked() */
358 fsnotify_put_mark(mark
);
362 * Free fsnotify mark. The mark is actually only marked as being freed. The
363 * freeing is actually happening only once last reference to the mark is
364 * dropped from a workqueue which first waits for srcu period end.
366 * Caller must have a reference to the mark or be protected by
367 * fsnotify_mark_srcu.
369 void fsnotify_free_mark(struct fsnotify_mark
*mark
)
371 struct fsnotify_group
*group
= mark
->group
;
373 spin_lock(&mark
->lock
);
374 /* something else already called this function on this mark */
375 if (!(mark
->flags
& FSNOTIFY_MARK_FLAG_ALIVE
)) {
376 spin_unlock(&mark
->lock
);
379 mark
->flags
&= ~FSNOTIFY_MARK_FLAG_ALIVE
;
380 spin_unlock(&mark
->lock
);
383 * Some groups like to know that marks are being freed. This is a
384 * callback to the group function to let it know that this mark
387 if (group
->ops
->freeing_mark
)
388 group
->ops
->freeing_mark(mark
, group
);
391 void fsnotify_destroy_mark(struct fsnotify_mark
*mark
,
392 struct fsnotify_group
*group
)
394 mutex_lock_nested(&group
->mark_mutex
, SINGLE_DEPTH_NESTING
);
395 fsnotify_detach_mark(mark
);
396 mutex_unlock(&group
->mark_mutex
);
397 fsnotify_free_mark(mark
);
399 EXPORT_SYMBOL_GPL(fsnotify_destroy_mark
);
402 * Sorting function for lists of fsnotify marks.
404 * Fanotify supports different notification classes (reflected as priority of
405 * notification group). Events shall be passed to notification groups in
406 * decreasing priority order. To achieve this marks in notification lists for
407 * inodes and vfsmounts are sorted so that priorities of corresponding groups
410 * Furthermore correct handling of the ignore mask requires processing inode
411 * and vfsmount marks of each group together. Using the group address as
412 * further sort criterion provides a unique sorting order and thus we can
413 * merge inode and vfsmount lists of marks in linear time and find groups
414 * present in both lists.
416 * A return value of 1 signifies that b has priority over a.
417 * A return value of 0 signifies that the two marks have to be handled together.
418 * A return value of -1 signifies that a has priority over b.
420 int fsnotify_compare_groups(struct fsnotify_group
*a
, struct fsnotify_group
*b
)
428 if (a
->priority
< b
->priority
)
430 if (a
->priority
> b
->priority
)
437 static int fsnotify_attach_connector_to_object(
438 struct fsnotify_mark_connector __rcu
**connp
,
440 struct vfsmount
*mnt
)
442 struct fsnotify_mark_connector
*conn
;
444 conn
= kmem_cache_alloc(fsnotify_mark_connector_cachep
, GFP_KERNEL
);
447 spin_lock_init(&conn
->lock
);
448 INIT_HLIST_HEAD(&conn
->list
);
450 conn
->flags
= FSNOTIFY_OBJ_TYPE_INODE
;
451 conn
->inode
= igrab(inode
);
453 conn
->flags
= FSNOTIFY_OBJ_TYPE_VFSMOUNT
;
457 * cmpxchg() provides the barrier so that readers of *connp can see
458 * only initialized structure
460 if (cmpxchg(connp
, NULL
, conn
)) {
461 /* Someone else created list structure for us */
464 kmem_cache_free(fsnotify_mark_connector_cachep
, conn
);
471 * Get mark connector, make sure it is alive and return with its lock held.
472 * This is for users that get connector pointer from inode or mount. Users that
473 * hold reference to a mark on the list may directly lock connector->lock as
474 * they are sure list cannot go away under them.
476 static struct fsnotify_mark_connector
*fsnotify_grab_connector(
477 struct fsnotify_mark_connector __rcu
**connp
)
479 struct fsnotify_mark_connector
*conn
;
482 idx
= srcu_read_lock(&fsnotify_mark_srcu
);
483 conn
= srcu_dereference(*connp
, &fsnotify_mark_srcu
);
486 spin_lock(&conn
->lock
);
487 if (!(conn
->flags
& (FSNOTIFY_OBJ_TYPE_INODE
|
488 FSNOTIFY_OBJ_TYPE_VFSMOUNT
))) {
489 spin_unlock(&conn
->lock
);
490 srcu_read_unlock(&fsnotify_mark_srcu
, idx
);
494 srcu_read_unlock(&fsnotify_mark_srcu
, idx
);
499 * Add mark into proper place in given list of marks. These marks may be used
500 * for the fsnotify backend to determine which event types should be delivered
501 * to which group and for which inodes. These marks are ordered according to
502 * priority, highest number first, and then by the group's location in memory.
504 static int fsnotify_add_mark_list(struct fsnotify_mark
*mark
,
505 struct inode
*inode
, struct vfsmount
*mnt
,
508 struct fsnotify_mark
*lmark
, *last
= NULL
;
509 struct fsnotify_mark_connector
*conn
;
510 struct fsnotify_mark_connector __rcu
**connp
;
514 if (WARN_ON(!inode
&& !mnt
))
517 connp
= &inode
->i_fsnotify_marks
;
519 connp
= &real_mount(mnt
)->mnt_fsnotify_marks
;
521 spin_lock(&mark
->lock
);
522 conn
= fsnotify_grab_connector(connp
);
524 spin_unlock(&mark
->lock
);
525 err
= fsnotify_attach_connector_to_object(connp
, inode
, mnt
);
531 /* is mark the first mark? */
532 if (hlist_empty(&conn
->list
)) {
533 hlist_add_head_rcu(&mark
->obj_list
, &conn
->list
);
537 /* should mark be in the middle of the current list? */
538 hlist_for_each_entry(lmark
, &conn
->list
, obj_list
) {
541 if ((lmark
->group
== mark
->group
) &&
542 (lmark
->flags
& FSNOTIFY_MARK_FLAG_ATTACHED
) &&
548 cmp
= fsnotify_compare_groups(lmark
->group
, mark
->group
);
550 hlist_add_before_rcu(&mark
->obj_list
, &lmark
->obj_list
);
555 BUG_ON(last
== NULL
);
556 /* mark should be the last entry. last is the current last entry */
557 hlist_add_behind_rcu(&mark
->obj_list
, &last
->obj_list
);
559 mark
->connector
= conn
;
561 spin_unlock(&conn
->lock
);
562 spin_unlock(&mark
->lock
);
567 * Attach an initialized mark to a given group and fs object.
568 * These marks may be used for the fsnotify backend to determine which
569 * event types should be delivered to which group.
571 int fsnotify_add_mark_locked(struct fsnotify_mark
*mark
, struct inode
*inode
,
572 struct vfsmount
*mnt
, int allow_dups
)
574 struct fsnotify_group
*group
= mark
->group
;
577 BUG_ON(inode
&& mnt
);
578 BUG_ON(!inode
&& !mnt
);
579 BUG_ON(!mutex_is_locked(&group
->mark_mutex
));
585 * mark->connector->lock
587 spin_lock(&mark
->lock
);
588 mark
->flags
|= FSNOTIFY_MARK_FLAG_ALIVE
| FSNOTIFY_MARK_FLAG_ATTACHED
;
590 list_add(&mark
->g_list
, &group
->marks_list
);
591 atomic_inc(&group
->num_marks
);
592 fsnotify_get_mark(mark
); /* for g_list */
593 spin_unlock(&mark
->lock
);
595 ret
= fsnotify_add_mark_list(mark
, inode
, mnt
, allow_dups
);
600 fsnotify_recalc_mask(mark
->connector
);
604 mark
->flags
&= ~(FSNOTIFY_MARK_FLAG_ALIVE
|
605 FSNOTIFY_MARK_FLAG_ATTACHED
);
606 list_del_init(&mark
->g_list
);
607 atomic_dec(&group
->num_marks
);
609 fsnotify_put_mark(mark
);
612 EXPORT_SYMBOL_GPL(fsnotify_add_mark
);
614 int fsnotify_add_mark(struct fsnotify_mark
*mark
, struct inode
*inode
,
615 struct vfsmount
*mnt
, int allow_dups
)
618 struct fsnotify_group
*group
= mark
->group
;
620 mutex_lock(&group
->mark_mutex
);
621 ret
= fsnotify_add_mark_locked(mark
, inode
, mnt
, allow_dups
);
622 mutex_unlock(&group
->mark_mutex
);
627 * Given a list of marks, find the mark associated with given group. If found
628 * take a reference to that mark and return it, else return NULL.
630 struct fsnotify_mark
*fsnotify_find_mark(
631 struct fsnotify_mark_connector __rcu
**connp
,
632 struct fsnotify_group
*group
)
634 struct fsnotify_mark_connector
*conn
;
635 struct fsnotify_mark
*mark
;
637 conn
= fsnotify_grab_connector(connp
);
641 hlist_for_each_entry(mark
, &conn
->list
, obj_list
) {
642 if (mark
->group
== group
&&
643 (mark
->flags
& FSNOTIFY_MARK_FLAG_ATTACHED
)) {
644 fsnotify_get_mark(mark
);
645 spin_unlock(&conn
->lock
);
649 spin_unlock(&conn
->lock
);
653 /* Clear any marks in a group with given type */
654 void fsnotify_clear_marks_by_group(struct fsnotify_group
*group
,
657 struct fsnotify_mark
*lmark
, *mark
;
659 struct list_head
*head
= &to_free
;
661 /* Skip selection step if we want to clear all marks. */
662 if (type
== FSNOTIFY_OBJ_ALL_TYPES
) {
663 head
= &group
->marks_list
;
667 * We have to be really careful here. Anytime we drop mark_mutex, e.g.
668 * fsnotify_clear_marks_by_inode() can come and free marks. Even in our
669 * to_free list so we have to use mark_mutex even when accessing that
670 * list. And freeing mark requires us to drop mark_mutex. So we can
671 * reliably free only the first mark in the list. That's why we first
672 * move marks to free to to_free list in one go and then free marks in
673 * to_free list one by one.
675 mutex_lock_nested(&group
->mark_mutex
, SINGLE_DEPTH_NESTING
);
676 list_for_each_entry_safe(mark
, lmark
, &group
->marks_list
, g_list
) {
677 if (mark
->connector
->flags
& type
)
678 list_move(&mark
->g_list
, &to_free
);
680 mutex_unlock(&group
->mark_mutex
);
684 mutex_lock_nested(&group
->mark_mutex
, SINGLE_DEPTH_NESTING
);
685 if (list_empty(head
)) {
686 mutex_unlock(&group
->mark_mutex
);
689 mark
= list_first_entry(head
, struct fsnotify_mark
, g_list
);
690 fsnotify_get_mark(mark
);
691 fsnotify_detach_mark(mark
);
692 mutex_unlock(&group
->mark_mutex
);
693 fsnotify_free_mark(mark
);
694 fsnotify_put_mark(mark
);
698 /* Destroy all marks attached to inode / vfsmount */
699 void fsnotify_destroy_marks(struct fsnotify_mark_connector __rcu
**connp
)
701 struct fsnotify_mark_connector
*conn
;
702 struct fsnotify_mark
*mark
, *old_mark
= NULL
;
705 conn
= fsnotify_grab_connector(connp
);
709 * We have to be careful since we can race with e.g.
710 * fsnotify_clear_marks_by_group() and once we drop the conn->lock, the
711 * list can get modified. However we are holding mark reference and
712 * thus our mark cannot be removed from obj_list so we can continue
713 * iteration after regaining conn->lock.
715 hlist_for_each_entry(mark
, &conn
->list
, obj_list
) {
716 fsnotify_get_mark(mark
);
717 spin_unlock(&conn
->lock
);
719 fsnotify_put_mark(old_mark
);
721 fsnotify_destroy_mark(mark
, mark
->group
);
722 spin_lock(&conn
->lock
);
725 * Detach list from object now so that we don't pin inode until all
726 * mark references get dropped. It would lead to strange results such
727 * as delaying inode deletion or blocking unmount.
729 inode
= fsnotify_detach_connector_from_object(conn
);
730 spin_unlock(&conn
->lock
);
732 fsnotify_put_mark(old_mark
);
737 * Nothing fancy, just initialize lists and locks and counters.
739 void fsnotify_init_mark(struct fsnotify_mark
*mark
,
740 struct fsnotify_group
*group
)
742 memset(mark
, 0, sizeof(*mark
));
743 spin_lock_init(&mark
->lock
);
744 atomic_set(&mark
->refcnt
, 1);
745 fsnotify_get_group(group
);
748 EXPORT_SYMBOL_GPL(fsnotify_init_mark
);
751 * Destroy all marks in destroy_list, waits for SRCU period to finish before
752 * actually freeing marks.
754 static void fsnotify_mark_destroy_workfn(struct work_struct
*work
)
756 struct fsnotify_mark
*mark
, *next
;
757 struct list_head private_destroy_list
;
759 spin_lock(&destroy_lock
);
760 /* exchange the list head */
761 list_replace_init(&destroy_list
, &private_destroy_list
);
762 spin_unlock(&destroy_lock
);
764 synchronize_srcu(&fsnotify_mark_srcu
);
766 list_for_each_entry_safe(mark
, next
, &private_destroy_list
, g_list
) {
767 list_del_init(&mark
->g_list
);
768 fsnotify_final_mark_destroy(mark
);
772 /* Wait for all marks queued for destruction to be actually destroyed */
773 void fsnotify_wait_marks_destroyed(void)
775 flush_delayed_work(&reaper_work
);