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c82ee6d3 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
90586523 EP |
2 | /* |
3 | * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> | |
90586523 EP |
4 | */ |
5 | ||
6 | #include <linux/dcache.h> | |
7 | #include <linux/fs.h> | |
5a0e3ad6 | 8 | #include <linux/gfp.h> |
90586523 EP |
9 | #include <linux/init.h> |
10 | #include <linux/module.h> | |
7131485a | 11 | #include <linux/mount.h> |
90586523 EP |
12 | #include <linux/srcu.h> |
13 | ||
14 | #include <linux/fsnotify_backend.h> | |
15 | #include "fsnotify.h" | |
16 | ||
3be25f49 EP |
17 | /* |
18 | * Clear all of the marks on an inode when it is being evicted from core | |
19 | */ | |
20 | void __fsnotify_inode_delete(struct inode *inode) | |
21 | { | |
22 | fsnotify_clear_marks_by_inode(inode); | |
23 | } | |
24 | EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); | |
25 | ||
ca9c726e AG |
26 | void __fsnotify_vfsmount_delete(struct vfsmount *mnt) |
27 | { | |
28 | fsnotify_clear_marks_by_mount(mnt); | |
29 | } | |
30 | ||
ebb3b47e JK |
31 | /** |
32 | * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
33 | * @sb: superblock being unmounted. | |
34 | * | |
35 | * Called during unmount with no locks held, so needs to be safe against | |
36 | * concurrent modifiers. We temporarily drop sb->s_inode_list_lock and CAN block. | |
37 | */ | |
1e6cb723 | 38 | static void fsnotify_unmount_inodes(struct super_block *sb) |
ebb3b47e JK |
39 | { |
40 | struct inode *inode, *iput_inode = NULL; | |
41 | ||
42 | spin_lock(&sb->s_inode_list_lock); | |
43 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { | |
44 | /* | |
45 | * We cannot __iget() an inode in state I_FREEING, | |
46 | * I_WILL_FREE, or I_NEW which is fine because by that point | |
47 | * the inode cannot have any associated watches. | |
48 | */ | |
49 | spin_lock(&inode->i_lock); | |
50 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { | |
51 | spin_unlock(&inode->i_lock); | |
52 | continue; | |
53 | } | |
54 | ||
55 | /* | |
56 | * If i_count is zero, the inode cannot have any watches and | |
1751e8a6 | 57 | * doing an __iget/iput with SB_ACTIVE clear would actually |
ebb3b47e JK |
58 | * evict all inodes with zero i_count from icache which is |
59 | * unnecessarily violent and may in fact be illegal to do. | |
1edc8eb2 ES |
60 | * However, we should have been called /after/ evict_inodes |
61 | * removed all zero refcount inodes, in any case. Test to | |
62 | * be sure. | |
ebb3b47e JK |
63 | */ |
64 | if (!atomic_read(&inode->i_count)) { | |
65 | spin_unlock(&inode->i_lock); | |
66 | continue; | |
67 | } | |
68 | ||
69 | __iget(inode); | |
70 | spin_unlock(&inode->i_lock); | |
71 | spin_unlock(&sb->s_inode_list_lock); | |
72 | ||
73 | if (iput_inode) | |
74 | iput(iput_inode); | |
75 | ||
76 | /* for each watch, send FS_UNMOUNT and then remove it */ | |
82ace1ef | 77 | fsnotify_inode(inode, FS_UNMOUNT); |
ebb3b47e JK |
78 | |
79 | fsnotify_inode_delete(inode); | |
80 | ||
81 | iput_inode = inode; | |
82 | ||
04646aeb | 83 | cond_resched(); |
ebb3b47e JK |
84 | spin_lock(&sb->s_inode_list_lock); |
85 | } | |
86 | spin_unlock(&sb->s_inode_list_lock); | |
87 | ||
88 | if (iput_inode) | |
89 | iput(iput_inode); | |
90 | } | |
91 | ||
1e6cb723 AG |
92 | void fsnotify_sb_delete(struct super_block *sb) |
93 | { | |
94 | fsnotify_unmount_inodes(sb); | |
95 | fsnotify_clear_marks_by_sb(sb); | |
ec44610f AG |
96 | /* Wait for outstanding object references from connectors */ |
97 | wait_var_event(&sb->s_fsnotify_connectors, | |
98 | !atomic_long_read(&sb->s_fsnotify_connectors)); | |
1e6cb723 AG |
99 | } |
100 | ||
c28f7e56 EP |
101 | /* |
102 | * Given an inode, first check if we care what happens to our children. Inotify | |
103 | * and dnotify both tell their parents about events. If we care about any event | |
104 | * on a child we run all of our children and set a dentry flag saying that the | |
105 | * parent cares. Thus when an event happens on a child it can quickly tell if | |
106 | * if there is a need to find a parent and send the event to the parent. | |
107 | */ | |
108 | void __fsnotify_update_child_dentry_flags(struct inode *inode) | |
109 | { | |
110 | struct dentry *alias; | |
111 | int watched; | |
112 | ||
113 | if (!S_ISDIR(inode->i_mode)) | |
114 | return; | |
115 | ||
116 | /* determine if the children should tell inode about their events */ | |
117 | watched = fsnotify_inode_watches_children(inode); | |
118 | ||
873feea0 | 119 | spin_lock(&inode->i_lock); |
c28f7e56 EP |
120 | /* run all of the dentries associated with this inode. Since this is a |
121 | * directory, there damn well better only be one item on this list */ | |
946e51f2 | 122 | hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { |
c28f7e56 EP |
123 | struct dentry *child; |
124 | ||
125 | /* run all of the children of the original inode and fix their | |
126 | * d_flags to indicate parental interest (their parent is the | |
127 | * original inode) */ | |
2fd6b7f5 | 128 | spin_lock(&alias->d_lock); |
946e51f2 | 129 | list_for_each_entry(child, &alias->d_subdirs, d_child) { |
c28f7e56 EP |
130 | if (!child->d_inode) |
131 | continue; | |
132 | ||
2fd6b7f5 | 133 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
c28f7e56 EP |
134 | if (watched) |
135 | child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; | |
136 | else | |
137 | child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; | |
138 | spin_unlock(&child->d_lock); | |
139 | } | |
2fd6b7f5 | 140 | spin_unlock(&alias->d_lock); |
c28f7e56 | 141 | } |
873feea0 | 142 | spin_unlock(&inode->i_lock); |
c28f7e56 EP |
143 | } |
144 | ||
9b93f331 AG |
145 | /* Are inode/sb/mount interested in parent and name info with this event? */ |
146 | static bool fsnotify_event_needs_parent(struct inode *inode, struct mount *mnt, | |
147 | __u32 mask) | |
148 | { | |
149 | __u32 marks_mask = 0; | |
150 | ||
151 | /* We only send parent/name to inode/sb/mount for events on non-dir */ | |
152 | if (mask & FS_ISDIR) | |
153 | return false; | |
154 | ||
fecc4559 AG |
155 | /* |
156 | * All events that are possible on child can also may be reported with | |
157 | * parent/name info to inode/sb/mount. Otherwise, a watching parent | |
158 | * could result in events reported with unexpected name info to sb/mount. | |
159 | */ | |
160 | BUILD_BUG_ON(FS_EVENTS_POSS_ON_CHILD & ~FS_EVENTS_POSS_TO_PARENT); | |
161 | ||
9b93f331 AG |
162 | /* Did either inode/sb/mount subscribe for events with parent/name? */ |
163 | marks_mask |= fsnotify_parent_needed_mask(inode->i_fsnotify_mask); | |
164 | marks_mask |= fsnotify_parent_needed_mask(inode->i_sb->s_fsnotify_mask); | |
165 | if (mnt) | |
166 | marks_mask |= fsnotify_parent_needed_mask(mnt->mnt_fsnotify_mask); | |
167 | ||
168 | /* Did they subscribe for this event with parent/name info? */ | |
169 | return mask & marks_mask; | |
170 | } | |
171 | ||
c738fbab AG |
172 | /* |
173 | * Notify this dentry's parent about a child's events with child name info | |
9b93f331 AG |
174 | * if parent is watching or if inode/sb/mount are interested in events with |
175 | * parent and name info. | |
176 | * | |
177 | * Notify only the child without name info if parent is not watching and | |
178 | * inode/sb/mount are not interested in events with parent and name info. | |
c738fbab | 179 | */ |
71d73410 | 180 | int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data, |
c738fbab | 181 | int data_type) |
c28f7e56 | 182 | { |
9b93f331 AG |
183 | const struct path *path = fsnotify_data_path(data, data_type); |
184 | struct mount *mnt = path ? real_mount(path->mnt) : NULL; | |
497b0c5a | 185 | struct inode *inode = d_inode(dentry); |
c28f7e56 | 186 | struct dentry *parent; |
9b93f331 | 187 | bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED; |
7372e79c | 188 | bool parent_needed, parent_interested; |
9b93f331 | 189 | __u32 p_mask; |
40a100d3 | 190 | struct inode *p_inode = NULL; |
497b0c5a AG |
191 | struct name_snapshot name; |
192 | struct qstr *file_name = NULL; | |
52420392 | 193 | int ret = 0; |
c28f7e56 | 194 | |
9b93f331 AG |
195 | /* |
196 | * Do inode/sb/mount care about parent and name info on non-dir? | |
197 | * Do they care about any event at all? | |
198 | */ | |
199 | if (!inode->i_fsnotify_marks && !inode->i_sb->s_fsnotify_marks && | |
200 | (!mnt || !mnt->mnt_fsnotify_marks) && !parent_watched) | |
201 | return 0; | |
202 | ||
497b0c5a | 203 | parent = NULL; |
7372e79c AG |
204 | parent_needed = fsnotify_event_needs_parent(inode, mnt, mask); |
205 | if (!parent_watched && !parent_needed) | |
497b0c5a | 206 | goto notify; |
c28f7e56 | 207 | |
9b93f331 | 208 | /* Does parent inode care about events on children? */ |
4d4eb366 | 209 | parent = dget_parent(dentry); |
c28f7e56 | 210 | p_inode = parent->d_inode; |
9b93f331 AG |
211 | p_mask = fsnotify_inode_watches_children(p_inode); |
212 | if (unlikely(parent_watched && !p_mask)) | |
4d4eb366 | 213 | __fsnotify_update_child_dentry_flags(p_inode); |
9b93f331 AG |
214 | |
215 | /* | |
216 | * Include parent/name in notification either if some notification | |
7372e79c | 217 | * groups require parent info or the parent is interested in this event. |
9b93f331 | 218 | */ |
7372e79c AG |
219 | parent_interested = mask & p_mask & ALL_FSNOTIFY_EVENTS; |
220 | if (parent_needed || parent_interested) { | |
497b0c5a AG |
221 | /* When notifying parent, child should be passed as data */ |
222 | WARN_ON_ONCE(inode != fsnotify_data_inode(data, data_type)); | |
49d31c2f | 223 | |
497b0c5a | 224 | /* Notify both parent and child with child name info */ |
49d31c2f | 225 | take_dentry_name_snapshot(&name, dentry); |
497b0c5a | 226 | file_name = &name.name; |
7372e79c | 227 | if (parent_interested) |
9b93f331 | 228 | mask |= FS_EVENT_ON_CHILD; |
c28f7e56 EP |
229 | } |
230 | ||
497b0c5a | 231 | notify: |
40a100d3 | 232 | ret = fsnotify(mask, data, data_type, p_inode, file_name, inode, 0); |
52420392 | 233 | |
497b0c5a AG |
234 | if (file_name) |
235 | release_dentry_name_snapshot(&name); | |
236 | dput(parent); | |
c738fbab | 237 | |
497b0c5a | 238 | return ret; |
c28f7e56 | 239 | } |
71d73410 | 240 | EXPORT_SYMBOL_GPL(__fsnotify_parent); |
c28f7e56 | 241 | |
950cc0d2 AG |
242 | static int fsnotify_handle_inode_event(struct fsnotify_group *group, |
243 | struct fsnotify_mark *inode_mark, | |
244 | u32 mask, const void *data, int data_type, | |
245 | struct inode *dir, const struct qstr *name, | |
246 | u32 cookie) | |
247 | { | |
248 | const struct path *path = fsnotify_data_path(data, data_type); | |
249 | struct inode *inode = fsnotify_data_inode(data, data_type); | |
250 | const struct fsnotify_ops *ops = group->ops; | |
251 | ||
252 | if (WARN_ON_ONCE(!ops->handle_inode_event)) | |
253 | return 0; | |
254 | ||
255 | if ((inode_mark->mask & FS_EXCL_UNLINK) && | |
256 | path && d_unlinked(path->dentry)) | |
257 | return 0; | |
258 | ||
fecc4559 AG |
259 | /* Check interest of this mark in case event was sent with two marks */ |
260 | if (!(mask & inode_mark->mask & ALL_FSNOTIFY_EVENTS)) | |
261 | return 0; | |
262 | ||
950cc0d2 AG |
263 | return ops->handle_inode_event(inode_mark, mask, inode, dir, name, cookie); |
264 | } | |
265 | ||
b9a1b977 AG |
266 | static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask, |
267 | const void *data, int data_type, | |
268 | struct inode *dir, const struct qstr *name, | |
269 | u32 cookie, struct fsnotify_iter_info *iter_info) | |
270 | { | |
271 | struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info); | |
fecc4559 | 272 | struct fsnotify_mark *parent_mark = fsnotify_iter_parent_mark(iter_info); |
b9a1b977 AG |
273 | int ret; |
274 | ||
b9a1b977 AG |
275 | if (WARN_ON_ONCE(fsnotify_iter_sb_mark(iter_info)) || |
276 | WARN_ON_ONCE(fsnotify_iter_vfsmount_mark(iter_info))) | |
277 | return 0; | |
278 | ||
fecc4559 AG |
279 | if (parent_mark) { |
280 | /* | |
281 | * parent_mark indicates that the parent inode is watching | |
282 | * children and interested in this event, which is an event | |
283 | * possible on child. But is *this mark* watching children and | |
284 | * interested in this event? | |
285 | */ | |
286 | if (parent_mark->mask & FS_EVENT_ON_CHILD) { | |
287 | ret = fsnotify_handle_inode_event(group, parent_mark, mask, | |
288 | data, data_type, dir, name, 0); | |
289 | if (ret) | |
290 | return ret; | |
291 | } | |
292 | if (!inode_mark) | |
293 | return 0; | |
294 | } | |
295 | ||
296 | if (mask & FS_EVENT_ON_CHILD) { | |
297 | /* | |
298 | * Some events can be sent on both parent dir and child marks | |
299 | * (e.g. FS_ATTRIB). If both parent dir and child are | |
300 | * watching, report the event once to parent dir with name (if | |
301 | * interested) and once to child without name (if interested). | |
302 | * The child watcher is expecting an event without a file name | |
303 | * and without the FS_EVENT_ON_CHILD flag. | |
304 | */ | |
305 | mask &= ~FS_EVENT_ON_CHILD; | |
b9a1b977 AG |
306 | dir = NULL; |
307 | name = NULL; | |
308 | } | |
309 | ||
fecc4559 AG |
310 | return fsnotify_handle_inode_event(group, inode_mark, mask, data, data_type, |
311 | dir, name, cookie); | |
b9a1b977 AG |
312 | } |
313 | ||
b54cecf5 AG |
314 | static int send_to_group(__u32 mask, const void *data, int data_type, |
315 | struct inode *dir, const struct qstr *file_name, | |
316 | u32 cookie, struct fsnotify_iter_info *iter_info) | |
7131485a | 317 | { |
faa9560a | 318 | struct fsnotify_group *group = NULL; |
007d1e83 | 319 | __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS); |
92183a42 AG |
320 | __u32 marks_mask = 0; |
321 | __u32 marks_ignored_mask = 0; | |
3dca1a74 AG |
322 | struct fsnotify_mark *mark; |
323 | int type; | |
613a807f | 324 | |
5b0457ad | 325 | if (WARN_ON(!iter_info->report_mask)) |
faa9560a | 326 | return 0; |
ce8f76fb EP |
327 | |
328 | /* clear ignored on inode modification */ | |
329 | if (mask & FS_MODIFY) { | |
3dca1a74 AG |
330 | fsnotify_foreach_obj_type(type) { |
331 | if (!fsnotify_iter_should_report_type(iter_info, type)) | |
332 | continue; | |
333 | mark = iter_info->marks[type]; | |
334 | if (mark && | |
335 | !(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) | |
336 | mark->ignored_mask = 0; | |
337 | } | |
ce8f76fb | 338 | } |
613a807f | 339 | |
3dca1a74 AG |
340 | fsnotify_foreach_obj_type(type) { |
341 | if (!fsnotify_iter_should_report_type(iter_info, type)) | |
342 | continue; | |
343 | mark = iter_info->marks[type]; | |
344 | /* does the object mark tell us to do something? */ | |
345 | if (mark) { | |
346 | group = mark->group; | |
347 | marks_mask |= mark->mask; | |
348 | marks_ignored_mask |= mark->ignored_mask; | |
349 | } | |
ce8f76fb EP |
350 | } |
351 | ||
b54cecf5 AG |
352 | pr_debug("%s: group=%p mask=%x marks_mask=%x marks_ignored_mask=%x data=%p data_type=%d dir=%p cookie=%d\n", |
353 | __func__, group, mask, marks_mask, marks_ignored_mask, | |
354 | data, data_type, dir, cookie); | |
faa9560a | 355 | |
92183a42 | 356 | if (!(test_mask & marks_mask & ~marks_ignored_mask)) |
613a807f EP |
357 | return 0; |
358 | ||
b9a1b977 AG |
359 | if (group->ops->handle_event) { |
360 | return group->ops->handle_event(group, mask, data, data_type, dir, | |
361 | file_name, cookie, iter_info); | |
362 | } | |
363 | ||
364 | return fsnotify_handle_event(group, mask, data, data_type, dir, | |
365 | file_name, cookie, iter_info); | |
7131485a EP |
366 | } |
367 | ||
3427ce71 MS |
368 | static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp) |
369 | { | |
370 | struct fsnotify_mark_connector *conn; | |
371 | struct hlist_node *node = NULL; | |
372 | ||
373 | conn = srcu_dereference(*connp, &fsnotify_mark_srcu); | |
374 | if (conn) | |
375 | node = srcu_dereference(conn->list.first, &fsnotify_mark_srcu); | |
376 | ||
377 | return hlist_entry_safe(node, struct fsnotify_mark, obj_list); | |
378 | } | |
379 | ||
380 | static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark) | |
381 | { | |
382 | struct hlist_node *node = NULL; | |
383 | ||
384 | if (mark) | |
385 | node = srcu_dereference(mark->obj_list.next, | |
386 | &fsnotify_mark_srcu); | |
387 | ||
388 | return hlist_entry_safe(node, struct fsnotify_mark, obj_list); | |
389 | } | |
390 | ||
d9a6f30b AG |
391 | /* |
392 | * iter_info is a multi head priority queue of marks. | |
393 | * Pick a subset of marks from queue heads, all with the | |
394 | * same group and set the report_mask for selected subset. | |
395 | * Returns the report_mask of the selected subset. | |
396 | */ | |
397 | static unsigned int fsnotify_iter_select_report_types( | |
398 | struct fsnotify_iter_info *iter_info) | |
399 | { | |
47d9c7cc AG |
400 | struct fsnotify_group *max_prio_group = NULL; |
401 | struct fsnotify_mark *mark; | |
402 | int type; | |
403 | ||
404 | /* Choose max prio group among groups of all queue heads */ | |
405 | fsnotify_foreach_obj_type(type) { | |
406 | mark = iter_info->marks[type]; | |
407 | if (mark && | |
408 | fsnotify_compare_groups(max_prio_group, mark->group) > 0) | |
409 | max_prio_group = mark->group; | |
410 | } | |
d9a6f30b | 411 | |
47d9c7cc | 412 | if (!max_prio_group) |
d9a6f30b AG |
413 | return 0; |
414 | ||
47d9c7cc | 415 | /* Set the report mask for marks from same group as max prio group */ |
d9a6f30b | 416 | iter_info->report_mask = 0; |
47d9c7cc AG |
417 | fsnotify_foreach_obj_type(type) { |
418 | mark = iter_info->marks[type]; | |
419 | if (mark && | |
420 | fsnotify_compare_groups(max_prio_group, mark->group) == 0) | |
421 | fsnotify_iter_set_report_type(iter_info, type); | |
422 | } | |
d9a6f30b AG |
423 | |
424 | return iter_info->report_mask; | |
425 | } | |
426 | ||
427 | /* | |
428 | * Pop from iter_info multi head queue, the marks that were iterated in the | |
429 | * current iteration step. | |
430 | */ | |
431 | static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info) | |
432 | { | |
47d9c7cc | 433 | int type; |
d9a6f30b | 434 | |
47d9c7cc AG |
435 | fsnotify_foreach_obj_type(type) { |
436 | if (fsnotify_iter_should_report_type(iter_info, type)) | |
437 | iter_info->marks[type] = | |
438 | fsnotify_next_mark(iter_info->marks[type]); | |
439 | } | |
d9a6f30b AG |
440 | } |
441 | ||
90586523 | 442 | /* |
40a100d3 AG |
443 | * fsnotify - This is the main call to fsnotify. |
444 | * | |
445 | * The VFS calls into hook specific functions in linux/fsnotify.h. | |
446 | * Those functions then in turn call here. Here will call out to all of the | |
447 | * registered fsnotify_group. Those groups can then use the notification event | |
448 | * in whatever means they feel necessary. | |
449 | * | |
450 | * @mask: event type and flags | |
451 | * @data: object that event happened on | |
452 | * @data_type: type of object for fanotify_data_XXX() accessors | |
453 | * @dir: optional directory associated with event - | |
454 | * if @file_name is not NULL, this is the directory that | |
455 | * @file_name is relative to | |
456 | * @file_name: optional file name associated with event | |
457 | * @inode: optional inode associated with event - | |
458 | * either @dir or @inode must be non-NULL. | |
459 | * if both are non-NULL event may be reported to both. | |
460 | * @cookie: inotify rename cookie | |
90586523 | 461 | */ |
40a100d3 AG |
462 | int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, |
463 | const struct qstr *file_name, struct inode *inode, u32 cookie) | |
90586523 | 464 | { |
b54cecf5 | 465 | const struct path *path = fsnotify_data_path(data, data_type); |
3427ce71 | 466 | struct fsnotify_iter_info iter_info = {}; |
40a100d3 | 467 | struct super_block *sb; |
60f7ed8c | 468 | struct mount *mnt = NULL; |
fecc4559 | 469 | struct inode *parent = NULL; |
9385a84d | 470 | int ret = 0; |
71d73410 | 471 | __u32 test_mask, marks_mask; |
90586523 | 472 | |
71d73410 | 473 | if (path) |
aa93bdc5 | 474 | mnt = real_mount(path->mnt); |
613a807f | 475 | |
40a100d3 AG |
476 | if (!inode) { |
477 | /* Dirent event - report on TYPE_INODE to dir */ | |
478 | inode = dir; | |
479 | } else if (mask & FS_EVENT_ON_CHILD) { | |
480 | /* | |
fecc4559 AG |
481 | * Event on child - report on TYPE_PARENT to dir if it is |
482 | * watching children and on TYPE_INODE to child. | |
40a100d3 | 483 | */ |
fecc4559 | 484 | parent = dir; |
40a100d3 AG |
485 | } |
486 | sb = inode->i_sb; | |
497b0c5a | 487 | |
7c49b861 DH |
488 | /* |
489 | * Optimization: srcu_read_lock() has a memory barrier which can | |
490 | * be expensive. It protects walking the *_fsnotify_marks lists. | |
491 | * However, if we do not walk the lists, we do not have to do | |
492 | * SRCU because we have no references to any objects and do not | |
493 | * need SRCU to keep them "alive". | |
494 | */ | |
9b93f331 | 495 | if (!sb->s_fsnotify_marks && |
497b0c5a | 496 | (!mnt || !mnt->mnt_fsnotify_marks) && |
9b93f331 | 497 | (!inode || !inode->i_fsnotify_marks) && |
fecc4559 | 498 | (!parent || !parent->i_fsnotify_marks)) |
7c49b861 | 499 | return 0; |
71d73410 | 500 | |
9b93f331 | 501 | marks_mask = sb->s_fsnotify_mask; |
497b0c5a AG |
502 | if (mnt) |
503 | marks_mask |= mnt->mnt_fsnotify_mask; | |
9b93f331 AG |
504 | if (inode) |
505 | marks_mask |= inode->i_fsnotify_mask; | |
fecc4559 AG |
506 | if (parent) |
507 | marks_mask |= parent->i_fsnotify_mask; | |
497b0c5a | 508 | |
71d73410 | 509 | |
613a807f EP |
510 | /* |
511 | * if this is a modify event we may need to clear the ignored masks | |
497b0c5a | 512 | * otherwise return if none of the marks care about this type of event. |
613a807f | 513 | */ |
71d73410 MG |
514 | test_mask = (mask & ALL_FSNOTIFY_EVENTS); |
515 | if (!(mask & FS_MODIFY) && !(test_mask & marks_mask)) | |
613a807f | 516 | return 0; |
3a9fb89f | 517 | |
9385a84d | 518 | iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); |
7131485a | 519 | |
45a9fb37 AG |
520 | iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = |
521 | fsnotify_first_mark(&sb->s_fsnotify_marks); | |
9bdda4e9 | 522 | if (mnt) { |
47d9c7cc | 523 | iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = |
3427ce71 | 524 | fsnotify_first_mark(&mnt->mnt_fsnotify_marks); |
90586523 | 525 | } |
9b93f331 AG |
526 | if (inode) { |
527 | iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = | |
528 | fsnotify_first_mark(&inode->i_fsnotify_marks); | |
529 | } | |
fecc4559 AG |
530 | if (parent) { |
531 | iter_info.marks[FSNOTIFY_OBJ_TYPE_PARENT] = | |
532 | fsnotify_first_mark(&parent->i_fsnotify_marks); | |
497b0c5a | 533 | } |
75c1be48 | 534 | |
8edc6e16 | 535 | /* |
60f7ed8c AG |
536 | * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark |
537 | * ignore masks are properly reflected for mount/sb mark notifications. | |
8edc6e16 JK |
538 | * That's why this traversal is so complicated... |
539 | */ | |
d9a6f30b | 540 | while (fsnotify_iter_select_report_types(&iter_info)) { |
b54cecf5 AG |
541 | ret = send_to_group(mask, data, data_type, dir, file_name, |
542 | cookie, &iter_info); | |
613a807f | 543 | |
ff8bcbd0 EP |
544 | if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) |
545 | goto out; | |
546 | ||
d9a6f30b | 547 | fsnotify_iter_next(&iter_info); |
7131485a | 548 | } |
ff8bcbd0 EP |
549 | ret = 0; |
550 | out: | |
9385a84d | 551 | srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx); |
c4ec54b4 | 552 | |
98b5c10d | 553 | return ret; |
90586523 EP |
554 | } |
555 | EXPORT_SYMBOL_GPL(fsnotify); | |
556 | ||
557 | static __init int fsnotify_init(void) | |
558 | { | |
75c1be48 EP |
559 | int ret; |
560 | ||
08b95c33 | 561 | BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 25); |
20dee624 | 562 | |
75c1be48 EP |
563 | ret = init_srcu_struct(&fsnotify_mark_srcu); |
564 | if (ret) | |
565 | panic("initializing fsnotify_mark_srcu"); | |
566 | ||
9dd813c1 JK |
567 | fsnotify_mark_connector_cachep = KMEM_CACHE(fsnotify_mark_connector, |
568 | SLAB_PANIC); | |
569 | ||
75c1be48 | 570 | return 0; |
90586523 | 571 | } |
75c1be48 | 572 | core_initcall(fsnotify_init); |