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5444e298 EP |
1 | /* |
2 | * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> | |
3 | * | |
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) | |
7 | * any later version. | |
8 | * | |
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. | |
13 | * | |
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. | |
17 | */ | |
18 | ||
19 | /* | |
20 | * fsnotify inode mark locking/lifetime/and refcnting | |
21 | * | |
22 | * REFCNT: | |
9756b918 LS |
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. | |
5444e298 EP |
29 | * |
30 | * LOCKING: | |
9756b918 LS |
31 | * There are 3 locks involved with fsnotify inode marks and they MUST be taken |
32 | * in order as follows: | |
5444e298 | 33 | * |
9756b918 | 34 | * group->mark_mutex |
5444e298 | 35 | * mark->lock |
5444e298 EP |
36 | * inode->i_lock |
37 | * | |
9756b918 LS |
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). | |
41 | ||
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. | |
5444e298 EP |
46 | * |
47 | * inode->i_lock protects the i_fsnotify_marks list anchored inside a | |
48 | * given inode and each mark is hooked via the i_list. (and sorta the | |
49 | * free_i_list) | |
50 | * | |
51 | * | |
52 | * LIFETIME: | |
53 | * Inode marks survive between when they are added to an inode and when their | |
54 | * refcnt==0. | |
55 | * | |
56 | * The inode mark can be cleared for a number of different reasons including: | |
57 | * - The inode is unlinked for the last time. (fsnotify_inode_remove) | |
58 | * - The inode is being evicted from cache. (fsnotify_inode_delete) | |
59 | * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) | |
60 | * - Something explicitly requests that it be removed. (fsnotify_destroy_mark) | |
61 | * - The fsnotify_group associated with the mark is going away and all such marks | |
62 | * need to be cleaned up. (fsnotify_clear_marks_by_group) | |
63 | * | |
64 | * Worst case we are given an inode and need to clean up all the marks on that | |
65 | * inode. We take i_lock and walk the i_fsnotify_marks safely. For each | |
66 | * mark on the list we take a reference (so the mark can't disappear under us). | |
67 | * We remove that mark form the inode's list of marks and we add this mark to a | |
9756b918 LS |
68 | * private list anchored on the stack using i_free_list; we walk i_free_list |
69 | * and before we destroy the mark we make sure that we dont race with a | |
70 | * concurrent destroy_group by getting a ref to the marks group and taking the | |
71 | * groups mutex. | |
72 | ||
5444e298 EP |
73 | * Very similarly for freeing by group, except we use free_g_list. |
74 | * | |
75 | * This has the very interesting property of being able to run concurrently with | |
76 | * any (or all) other directions. | |
77 | */ | |
78 | ||
79 | #include <linux/fs.h> | |
80 | #include <linux/init.h> | |
81 | #include <linux/kernel.h> | |
75c1be48 | 82 | #include <linux/kthread.h> |
5444e298 EP |
83 | #include <linux/module.h> |
84 | #include <linux/mutex.h> | |
85 | #include <linux/slab.h> | |
86 | #include <linux/spinlock.h> | |
75c1be48 | 87 | #include <linux/srcu.h> |
5444e298 | 88 | |
60063497 | 89 | #include <linux/atomic.h> |
5444e298 EP |
90 | |
91 | #include <linux/fsnotify_backend.h> | |
92 | #include "fsnotify.h" | |
93 | ||
75c1be48 EP |
94 | struct srcu_struct fsnotify_mark_srcu; |
95 | static DEFINE_SPINLOCK(destroy_lock); | |
96 | static LIST_HEAD(destroy_list); | |
97 | static DECLARE_WAIT_QUEUE_HEAD(destroy_waitq); | |
98 | ||
5444e298 EP |
99 | void fsnotify_get_mark(struct fsnotify_mark *mark) |
100 | { | |
101 | atomic_inc(&mark->refcnt); | |
102 | } | |
103 | ||
104 | void fsnotify_put_mark(struct fsnotify_mark *mark) | |
105 | { | |
23e964c2 LS |
106 | if (atomic_dec_and_test(&mark->refcnt)) { |
107 | if (mark->group) | |
108 | fsnotify_put_group(mark->group); | |
5444e298 | 109 | mark->free_mark(mark); |
23e964c2 | 110 | } |
5444e298 EP |
111 | } |
112 | ||
0809ab69 JK |
113 | /* Calculate mask of events for a list of marks */ |
114 | u32 fsnotify_recalc_mask(struct hlist_head *head) | |
115 | { | |
116 | u32 new_mask = 0; | |
117 | struct fsnotify_mark *mark; | |
118 | ||
119 | hlist_for_each_entry(mark, head, obj_list) | |
120 | new_mask |= mark->mask; | |
121 | return new_mask; | |
122 | } | |
123 | ||
5444e298 | 124 | /* |
4712e722 JK |
125 | * Remove mark from inode / vfsmount list, group list, drop inode reference |
126 | * if we got one. | |
127 | * | |
128 | * Must be called with group->mark_mutex held. | |
5444e298 | 129 | */ |
4712e722 | 130 | void fsnotify_detach_mark(struct fsnotify_mark *mark) |
5444e298 | 131 | { |
0d48b7f0 | 132 | struct inode *inode = NULL; |
4712e722 | 133 | struct fsnotify_group *group = mark->group; |
5444e298 | 134 | |
d5a335b8 LS |
135 | BUG_ON(!mutex_is_locked(&group->mark_mutex)); |
136 | ||
104d06f0 | 137 | spin_lock(&mark->lock); |
5444e298 | 138 | |
700307a2 | 139 | /* something else already called this function on this mark */ |
4712e722 | 140 | if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) { |
5444e298 | 141 | spin_unlock(&mark->lock); |
e2a29943 | 142 | return; |
5444e298 EP |
143 | } |
144 | ||
4712e722 | 145 | mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED; |
700307a2 | 146 | |
0d48b7f0 | 147 | if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) { |
0809ab69 | 148 | inode = mark->inode; |
b31d397e | 149 | fsnotify_destroy_inode_mark(mark); |
0d48b7f0 EP |
150 | } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT) |
151 | fsnotify_destroy_vfsmount_mark(mark); | |
5444e298 EP |
152 | else |
153 | BUG(); | |
4712e722 JK |
154 | /* |
155 | * Note that we didn't update flags telling whether inode cares about | |
156 | * what's happening with children. We update these flags from | |
157 | * __fsnotify_parent() lazily when next event happens on one of our | |
158 | * children. | |
159 | */ | |
5444e298 EP |
160 | |
161 | list_del_init(&mark->g_list); | |
d725e66c | 162 | |
5444e298 | 163 | spin_unlock(&mark->lock); |
d5a335b8 | 164 | |
6960b0d9 LS |
165 | if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) |
166 | iput(inode); | |
4712e722 JK |
167 | |
168 | atomic_dec(&group->num_marks); | |
169 | } | |
170 | ||
171 | /* | |
172 | * Free fsnotify mark. The freeing is actually happening from a kthread which | |
173 | * first waits for srcu period end. Caller must have a reference to the mark | |
174 | * or be protected by fsnotify_mark_srcu. | |
175 | */ | |
176 | void fsnotify_free_mark(struct fsnotify_mark *mark) | |
177 | { | |
178 | struct fsnotify_group *group = mark->group; | |
179 | ||
180 | spin_lock(&mark->lock); | |
181 | /* something else already called this function on this mark */ | |
182 | if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { | |
183 | spin_unlock(&mark->lock); | |
184 | return; | |
185 | } | |
186 | mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; | |
187 | spin_unlock(&mark->lock); | |
5444e298 | 188 | |
75c1be48 | 189 | spin_lock(&destroy_lock); |
37d469e7 | 190 | list_add(&mark->g_list, &destroy_list); |
75c1be48 EP |
191 | spin_unlock(&destroy_lock); |
192 | wake_up(&destroy_waitq); | |
d725e66c LT |
193 | |
194 | /* | |
195 | * Some groups like to know that marks are being freed. This is a | |
196 | * callback to the group function to let it know that this mark | |
197 | * is being freed. | |
198 | */ | |
199 | if (group->ops->freeing_mark) | |
200 | group->ops->freeing_mark(mark, group); | |
d5a335b8 LS |
201 | } |
202 | ||
203 | void fsnotify_destroy_mark(struct fsnotify_mark *mark, | |
204 | struct fsnotify_group *group) | |
205 | { | |
6960b0d9 | 206 | mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); |
4712e722 | 207 | fsnotify_detach_mark(mark); |
d5a335b8 | 208 | mutex_unlock(&group->mark_mutex); |
4712e722 | 209 | fsnotify_free_mark(mark); |
5444e298 EP |
210 | } |
211 | ||
925d1132 | 212 | void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock) |
0809ab69 | 213 | { |
925d1132 | 214 | struct fsnotify_mark *mark; |
0809ab69 | 215 | |
925d1132 JK |
216 | while (1) { |
217 | /* | |
218 | * We have to be careful since we can race with e.g. | |
219 | * fsnotify_clear_marks_by_group() and once we drop 'lock', | |
220 | * mark can get removed from the obj_list and destroyed. But | |
221 | * we are holding mark reference so mark cannot be freed and | |
222 | * calling fsnotify_destroy_mark() more than once is fine. | |
223 | */ | |
224 | spin_lock(lock); | |
225 | if (hlist_empty(head)) { | |
226 | spin_unlock(lock); | |
227 | break; | |
228 | } | |
229 | mark = hlist_entry(head->first, struct fsnotify_mark, obj_list); | |
230 | /* | |
231 | * We don't update i_fsnotify_mask / mnt_fsnotify_mask here | |
232 | * since inode / mount is going away anyway. So just remove | |
233 | * mark from the list. | |
234 | */ | |
235 | hlist_del_init_rcu(&mark->obj_list); | |
236 | fsnotify_get_mark(mark); | |
237 | spin_unlock(lock); | |
238 | fsnotify_destroy_mark(mark, mark->group); | |
0809ab69 | 239 | fsnotify_put_mark(mark); |
0809ab69 JK |
240 | } |
241 | } | |
242 | ||
90b1e7a5 EP |
243 | void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask) |
244 | { | |
245 | assert_spin_locked(&mark->lock); | |
246 | ||
247 | mark->mask = mask; | |
248 | ||
249 | if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) | |
250 | fsnotify_set_inode_mark_mask_locked(mark, mask); | |
251 | } | |
252 | ||
33af5e32 EP |
253 | void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask) |
254 | { | |
255 | assert_spin_locked(&mark->lock); | |
256 | ||
257 | mark->ignored_mask = mask; | |
258 | } | |
90b1e7a5 | 259 | |
8edc6e16 JK |
260 | /* |
261 | * Sorting function for lists of fsnotify marks. | |
262 | * | |
263 | * Fanotify supports different notification classes (reflected as priority of | |
264 | * notification group). Events shall be passed to notification groups in | |
265 | * decreasing priority order. To achieve this marks in notification lists for | |
266 | * inodes and vfsmounts are sorted so that priorities of corresponding groups | |
267 | * are descending. | |
268 | * | |
269 | * Furthermore correct handling of the ignore mask requires processing inode | |
270 | * and vfsmount marks of each group together. Using the group address as | |
271 | * further sort criterion provides a unique sorting order and thus we can | |
272 | * merge inode and vfsmount lists of marks in linear time and find groups | |
273 | * present in both lists. | |
274 | * | |
275 | * A return value of 1 signifies that b has priority over a. | |
276 | * A return value of 0 signifies that the two marks have to be handled together. | |
277 | * A return value of -1 signifies that a has priority over b. | |
278 | */ | |
279 | int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b) | |
280 | { | |
281 | if (a == b) | |
282 | return 0; | |
283 | if (!a) | |
284 | return 1; | |
285 | if (!b) | |
286 | return -1; | |
287 | if (a->priority < b->priority) | |
288 | return 1; | |
289 | if (a->priority > b->priority) | |
290 | return -1; | |
291 | if (a < b) | |
292 | return 1; | |
293 | return -1; | |
294 | } | |
295 | ||
0809ab69 JK |
296 | /* Add mark into proper place in given list of marks */ |
297 | int fsnotify_add_mark_list(struct hlist_head *head, struct fsnotify_mark *mark, | |
298 | int allow_dups) | |
299 | { | |
300 | struct fsnotify_mark *lmark, *last = NULL; | |
301 | int cmp; | |
302 | ||
303 | /* is mark the first mark? */ | |
304 | if (hlist_empty(head)) { | |
305 | hlist_add_head_rcu(&mark->obj_list, head); | |
306 | return 0; | |
307 | } | |
308 | ||
309 | /* should mark be in the middle of the current list? */ | |
310 | hlist_for_each_entry(lmark, head, obj_list) { | |
311 | last = lmark; | |
312 | ||
313 | if ((lmark->group == mark->group) && !allow_dups) | |
314 | return -EEXIST; | |
315 | ||
316 | cmp = fsnotify_compare_groups(lmark->group, mark->group); | |
317 | if (cmp >= 0) { | |
318 | hlist_add_before_rcu(&mark->obj_list, &lmark->obj_list); | |
319 | return 0; | |
320 | } | |
321 | } | |
322 | ||
323 | BUG_ON(last == NULL); | |
324 | /* mark should be the last entry. last is the current last entry */ | |
325 | hlist_add_behind_rcu(&mark->obj_list, &last->obj_list); | |
326 | return 0; | |
327 | } | |
328 | ||
5444e298 EP |
329 | /* |
330 | * Attach an initialized mark to a given group and fs object. | |
331 | * These marks may be used for the fsnotify backend to determine which | |
332 | * event types should be delivered to which group. | |
333 | */ | |
d5a335b8 LS |
334 | int fsnotify_add_mark_locked(struct fsnotify_mark *mark, |
335 | struct fsnotify_group *group, struct inode *inode, | |
336 | struct vfsmount *mnt, int allow_dups) | |
5444e298 EP |
337 | { |
338 | int ret = 0; | |
339 | ||
5444e298 EP |
340 | BUG_ON(inode && mnt); |
341 | BUG_ON(!inode && !mnt); | |
d5a335b8 | 342 | BUG_ON(!mutex_is_locked(&group->mark_mutex)); |
5444e298 | 343 | |
5444e298 EP |
344 | /* |
345 | * LOCKING ORDER!!!! | |
986ab098 | 346 | * group->mark_mutex |
104d06f0 | 347 | * mark->lock |
5444e298 EP |
348 | * inode->i_lock |
349 | */ | |
104d06f0 | 350 | spin_lock(&mark->lock); |
4712e722 | 351 | mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_ATTACHED; |
700307a2 | 352 | |
23e964c2 | 353 | fsnotify_get_group(group); |
5444e298 EP |
354 | mark->group = group; |
355 | list_add(&mark->g_list, &group->marks_list); | |
356 | atomic_inc(&group->num_marks); | |
357 | fsnotify_get_mark(mark); /* for i_list and g_list */ | |
358 | ||
359 | if (inode) { | |
360 | ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups); | |
361 | if (ret) | |
362 | goto err; | |
0d48b7f0 EP |
363 | } else if (mnt) { |
364 | ret = fsnotify_add_vfsmount_mark(mark, group, mnt, allow_dups); | |
365 | if (ret) | |
366 | goto err; | |
5444e298 EP |
367 | } else { |
368 | BUG(); | |
369 | } | |
370 | ||
90b1e7a5 EP |
371 | /* this will pin the object if appropriate */ |
372 | fsnotify_set_mark_mask_locked(mark, mark->mask); | |
5444e298 EP |
373 | spin_unlock(&mark->lock); |
374 | ||
375 | if (inode) | |
376 | __fsnotify_update_child_dentry_flags(inode); | |
377 | ||
378 | return ret; | |
379 | err: | |
700307a2 | 380 | mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; |
5444e298 | 381 | list_del_init(&mark->g_list); |
23e964c2 | 382 | fsnotify_put_group(group); |
75c1be48 | 383 | mark->group = NULL; |
5444e298 | 384 | atomic_dec(&group->num_marks); |
5444e298 | 385 | |
5444e298 EP |
386 | spin_unlock(&mark->lock); |
387 | ||
75c1be48 | 388 | spin_lock(&destroy_lock); |
37d469e7 | 389 | list_add(&mark->g_list, &destroy_list); |
75c1be48 EP |
390 | spin_unlock(&destroy_lock); |
391 | wake_up(&destroy_waitq); | |
392 | ||
5444e298 EP |
393 | return ret; |
394 | } | |
395 | ||
d5a335b8 LS |
396 | int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group, |
397 | struct inode *inode, struct vfsmount *mnt, int allow_dups) | |
398 | { | |
399 | int ret; | |
400 | mutex_lock(&group->mark_mutex); | |
401 | ret = fsnotify_add_mark_locked(mark, group, inode, mnt, allow_dups); | |
402 | mutex_unlock(&group->mark_mutex); | |
403 | return ret; | |
404 | } | |
405 | ||
0809ab69 JK |
406 | /* |
407 | * Given a list of marks, find the mark associated with given group. If found | |
408 | * take a reference to that mark and return it, else return NULL. | |
409 | */ | |
410 | struct fsnotify_mark *fsnotify_find_mark(struct hlist_head *head, | |
411 | struct fsnotify_group *group) | |
412 | { | |
413 | struct fsnotify_mark *mark; | |
414 | ||
415 | hlist_for_each_entry(mark, head, obj_list) { | |
416 | if (mark->group == group) { | |
417 | fsnotify_get_mark(mark); | |
418 | return mark; | |
419 | } | |
420 | } | |
421 | return NULL; | |
422 | } | |
423 | ||
5444e298 | 424 | /* |
d725e66c | 425 | * clear any marks in a group in which mark->flags & flags is true |
5444e298 | 426 | */ |
4d92604c EP |
427 | void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, |
428 | unsigned int flags) | |
5444e298 EP |
429 | { |
430 | struct fsnotify_mark *lmark, *mark; | |
8f2f3eb5 | 431 | LIST_HEAD(to_free); |
5444e298 | 432 | |
8f2f3eb5 JK |
433 | /* |
434 | * We have to be really careful here. Anytime we drop mark_mutex, e.g. | |
435 | * fsnotify_clear_marks_by_inode() can come and free marks. Even in our | |
436 | * to_free list so we have to use mark_mutex even when accessing that | |
437 | * list. And freeing mark requires us to drop mark_mutex. So we can | |
438 | * reliably free only the first mark in the list. That's why we first | |
439 | * move marks to free to to_free list in one go and then free marks in | |
440 | * to_free list one by one. | |
441 | */ | |
6960b0d9 | 442 | mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); |
5444e298 | 443 | list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) { |
8f2f3eb5 JK |
444 | if (mark->flags & flags) |
445 | list_move(&mark->g_list, &to_free); | |
5444e298 | 446 | } |
986ab098 | 447 | mutex_unlock(&group->mark_mutex); |
8f2f3eb5 JK |
448 | |
449 | while (1) { | |
450 | mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); | |
451 | if (list_empty(&to_free)) { | |
452 | mutex_unlock(&group->mark_mutex); | |
453 | break; | |
454 | } | |
455 | mark = list_first_entry(&to_free, struct fsnotify_mark, g_list); | |
456 | fsnotify_get_mark(mark); | |
4712e722 | 457 | fsnotify_detach_mark(mark); |
8f2f3eb5 | 458 | mutex_unlock(&group->mark_mutex); |
4712e722 | 459 | fsnotify_free_mark(mark); |
8f2f3eb5 JK |
460 | fsnotify_put_mark(mark); |
461 | } | |
5444e298 EP |
462 | } |
463 | ||
4d92604c EP |
464 | /* |
465 | * Given a group, destroy all of the marks associated with that group. | |
466 | */ | |
467 | void fsnotify_clear_marks_by_group(struct fsnotify_group *group) | |
468 | { | |
469 | fsnotify_clear_marks_by_group_flags(group, (unsigned int)-1); | |
470 | } | |
471 | ||
5444e298 EP |
472 | void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) |
473 | { | |
474 | assert_spin_locked(&old->lock); | |
0809ab69 JK |
475 | new->inode = old->inode; |
476 | new->mnt = old->mnt; | |
23e964c2 LS |
477 | if (old->group) |
478 | fsnotify_get_group(old->group); | |
5444e298 EP |
479 | new->group = old->group; |
480 | new->mask = old->mask; | |
481 | new->free_mark = old->free_mark; | |
482 | } | |
483 | ||
484 | /* | |
485 | * Nothing fancy, just initialize lists and locks and counters. | |
486 | */ | |
487 | void fsnotify_init_mark(struct fsnotify_mark *mark, | |
488 | void (*free_mark)(struct fsnotify_mark *mark)) | |
489 | { | |
ba643f04 | 490 | memset(mark, 0, sizeof(*mark)); |
5444e298 EP |
491 | spin_lock_init(&mark->lock); |
492 | atomic_set(&mark->refcnt, 1); | |
5444e298 EP |
493 | mark->free_mark = free_mark; |
494 | } | |
75c1be48 EP |
495 | |
496 | static int fsnotify_mark_destroy(void *ignored) | |
497 | { | |
498 | struct fsnotify_mark *mark, *next; | |
efa8f7e5 | 499 | struct list_head private_destroy_list; |
75c1be48 EP |
500 | |
501 | for (;;) { | |
502 | spin_lock(&destroy_lock); | |
8778abb9 AG |
503 | /* exchange the list head */ |
504 | list_replace_init(&destroy_list, &private_destroy_list); | |
75c1be48 EP |
505 | spin_unlock(&destroy_lock); |
506 | ||
507 | synchronize_srcu(&fsnotify_mark_srcu); | |
508 | ||
37d469e7 JK |
509 | list_for_each_entry_safe(mark, next, &private_destroy_list, g_list) { |
510 | list_del_init(&mark->g_list); | |
75c1be48 EP |
511 | fsnotify_put_mark(mark); |
512 | } | |
513 | ||
514 | wait_event_interruptible(destroy_waitq, !list_empty(&destroy_list)); | |
515 | } | |
516 | ||
517 | return 0; | |
518 | } | |
519 | ||
520 | static int __init fsnotify_mark_init(void) | |
521 | { | |
522 | struct task_struct *thread; | |
523 | ||
524 | thread = kthread_run(fsnotify_mark_destroy, NULL, | |
525 | "fsnotify_mark"); | |
526 | if (IS_ERR(thread)) | |
527 | panic("unable to start fsnotify mark destruction thread."); | |
528 | ||
529 | return 0; | |
530 | } | |
531 | device_initcall(fsnotify_mark_init); |