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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#include <linux/dcache.h>
20#include <linux/fs.h>
21#include <linux/gfp.h>
22#include <linux/init.h>
23#include <linux/module.h>
24#include <linux/mount.h>
25#include <linux/srcu.h>
26
27#include <linux/fsnotify_backend.h>
28#include "fsnotify.h"
29
30/*
31 * Clear all of the marks on an inode when it is being evicted from core
32 */
33void __fsnotify_inode_delete(struct inode *inode)
34{
35 fsnotify_clear_marks_by_inode(inode);
36}
37EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
38
39void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
40{
41 fsnotify_clear_marks_by_mount(mnt);
42}
43
44/**
45 * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
46 * @sb: superblock being unmounted.
47 *
48 * Called during unmount with no locks held, so needs to be safe against
49 * concurrent modifiers. We temporarily drop sb->s_inode_list_lock and CAN block.
50 */
51void fsnotify_unmount_inodes(struct super_block *sb)
52{
53 struct inode *inode, *iput_inode = NULL;
54
55 spin_lock(&sb->s_inode_list_lock);
56 list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
57 /*
58 * We cannot __iget() an inode in state I_FREEING,
59 * I_WILL_FREE, or I_NEW which is fine because by that point
60 * the inode cannot have any associated watches.
61 */
62 spin_lock(&inode->i_lock);
63 if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
64 spin_unlock(&inode->i_lock);
65 continue;
66 }
67
68 /*
69 * If i_count is zero, the inode cannot have any watches and
70 * doing an __iget/iput with SB_ACTIVE clear would actually
71 * evict all inodes with zero i_count from icache which is
72 * unnecessarily violent and may in fact be illegal to do.
73 */
74 if (!atomic_read(&inode->i_count)) {
75 spin_unlock(&inode->i_lock);
76 continue;
77 }
78
79 __iget(inode);
80 spin_unlock(&inode->i_lock);
81 spin_unlock(&sb->s_inode_list_lock);
82
83 if (iput_inode)
84 iput(iput_inode);
85
86 /* for each watch, send FS_UNMOUNT and then remove it */
87 fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
88
89 fsnotify_inode_delete(inode);
90
91 iput_inode = inode;
92
93 spin_lock(&sb->s_inode_list_lock);
94 }
95 spin_unlock(&sb->s_inode_list_lock);
96
97 if (iput_inode)
98 iput(iput_inode);
99}
100
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 */
108void __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
119 spin_lock(&inode->i_lock);
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 */
122 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
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) */
128 spin_lock(&alias->d_lock);
129 list_for_each_entry(child, &alias->d_subdirs, d_child) {
130 if (!child->d_inode)
131 continue;
132
133 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
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 }
140 spin_unlock(&alias->d_lock);
141 }
142 spin_unlock(&inode->i_lock);
143}
144
145/* Notify this dentry's parent about a child's events. */
146int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask)
147{
148 struct dentry *parent;
149 struct inode *p_inode;
150 int ret = 0;
151
152 if (!dentry)
153 dentry = path->dentry;
154
155 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
156 return 0;
157
158 parent = dget_parent(dentry);
159 p_inode = parent->d_inode;
160
161 if (unlikely(!fsnotify_inode_watches_children(p_inode)))
162 __fsnotify_update_child_dentry_flags(p_inode);
163 else if (p_inode->i_fsnotify_mask & mask) {
164 struct name_snapshot name;
165
166 /* we are notifying a parent so come up with the new mask which
167 * specifies these are events which came from a child. */
168 mask |= FS_EVENT_ON_CHILD;
169
170 take_dentry_name_snapshot(&name, dentry);
171 if (path)
172 ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
173 name.name, 0);
174 else
175 ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
176 name.name, 0);
177 release_dentry_name_snapshot(&name);
178 }
179
180 dput(parent);
181
182 return ret;
183}
184EXPORT_SYMBOL_GPL(__fsnotify_parent);
185
186static int send_to_group(struct inode *to_tell,
187 struct fsnotify_mark *inode_mark,
188 struct fsnotify_mark *vfsmount_mark,
189 __u32 mask, const void *data,
190 int data_is, u32 cookie,
191 const unsigned char *file_name,
192 struct fsnotify_iter_info *iter_info)
193{
194 struct fsnotify_group *group = NULL;
195 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
196 __u32 marks_mask = 0;
197 __u32 marks_ignored_mask = 0;
198
199 if (unlikely(!inode_mark && !vfsmount_mark)) {
200 BUG();
201 return 0;
202 }
203
204 /* clear ignored on inode modification */
205 if (mask & FS_MODIFY) {
206 if (inode_mark &&
207 !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
208 inode_mark->ignored_mask = 0;
209 if (vfsmount_mark &&
210 !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
211 vfsmount_mark->ignored_mask = 0;
212 }
213
214 /* does the inode mark tell us to do something? */
215 if (inode_mark) {
216 group = inode_mark->group;
217 marks_mask |= inode_mark->mask;
218 marks_ignored_mask |= inode_mark->ignored_mask;
219 }
220
221 /* does the vfsmount_mark tell us to do something? */
222 if (vfsmount_mark) {
223 group = vfsmount_mark->group;
224 marks_mask |= vfsmount_mark->mask;
225 marks_ignored_mask |= vfsmount_mark->ignored_mask;
226 }
227
228 pr_debug("%s: group=%p to_tell=%p mask=%x inode_mark=%p"
229 " vfsmount_mark=%p marks_mask=%x marks_ignored_mask=%x"
230 " data=%p data_is=%d cookie=%d\n",
231 __func__, group, to_tell, mask, inode_mark, vfsmount_mark,
232 marks_mask, marks_ignored_mask, data,
233 data_is, cookie);
234
235 if (!(test_mask & marks_mask & ~marks_ignored_mask))
236 return 0;
237
238 return group->ops->handle_event(group, to_tell, inode_mark,
239 vfsmount_mark, mask, data, data_is,
240 file_name, cookie, iter_info);
241}
242
243static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp)
244{
245 struct fsnotify_mark_connector *conn;
246 struct hlist_node *node = NULL;
247
248 conn = srcu_dereference(*connp, &fsnotify_mark_srcu);
249 if (conn)
250 node = srcu_dereference(conn->list.first, &fsnotify_mark_srcu);
251
252 return hlist_entry_safe(node, struct fsnotify_mark, obj_list);
253}
254
255static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark)
256{
257 struct hlist_node *node = NULL;
258
259 if (mark)
260 node = srcu_dereference(mark->obj_list.next,
261 &fsnotify_mark_srcu);
262
263 return hlist_entry_safe(node, struct fsnotify_mark, obj_list);
264}
265
266/*
267 * This is the main call to fsnotify. The VFS calls into hook specific functions
268 * in linux/fsnotify.h. Those functions then in turn call here. Here will call
269 * out to all of the registered fsnotify_group. Those groups can then use the
270 * notification event in whatever means they feel necessary.
271 */
272int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
273 const unsigned char *file_name, u32 cookie)
274{
275 struct fsnotify_iter_info iter_info = {};
276 struct mount *mnt;
277 int ret = 0;
278 /* global tests shouldn't care about events on child only the specific event */
279 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
280
281 if (data_is == FSNOTIFY_EVENT_PATH)
282 mnt = real_mount(((const struct path *)data)->mnt);
283 else
284 mnt = NULL;
285
286 /*
287 * Optimization: srcu_read_lock() has a memory barrier which can
288 * be expensive. It protects walking the *_fsnotify_marks lists.
289 * However, if we do not walk the lists, we do not have to do
290 * SRCU because we have no references to any objects and do not
291 * need SRCU to keep them "alive".
292 */
293 if (!to_tell->i_fsnotify_marks &&
294 (!mnt || !mnt->mnt_fsnotify_marks))
295 return 0;
296 /*
297 * if this is a modify event we may need to clear the ignored masks
298 * otherwise return if neither the inode nor the vfsmount care about
299 * this type of event.
300 */
301 if (!(mask & FS_MODIFY) &&
302 !(test_mask & to_tell->i_fsnotify_mask) &&
303 !(mnt && test_mask & mnt->mnt_fsnotify_mask))
304 return 0;
305
306 iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
307
308 if ((mask & FS_MODIFY) ||
309 (test_mask & to_tell->i_fsnotify_mask)) {
310 iter_info.inode_mark =
311 fsnotify_first_mark(&to_tell->i_fsnotify_marks);
312 }
313
314 if (mnt && ((mask & FS_MODIFY) ||
315 (test_mask & mnt->mnt_fsnotify_mask))) {
316 iter_info.inode_mark =
317 fsnotify_first_mark(&to_tell->i_fsnotify_marks);
318 iter_info.vfsmount_mark =
319 fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
320 }
321
322 /*
323 * We need to merge inode & vfsmount mark lists so that inode mark
324 * ignore masks are properly reflected for mount mark notifications.
325 * That's why this traversal is so complicated...
326 */
327 while (iter_info.inode_mark || iter_info.vfsmount_mark) {
328 struct fsnotify_mark *inode_mark = iter_info.inode_mark;
329 struct fsnotify_mark *vfsmount_mark = iter_info.vfsmount_mark;
330
331 if (inode_mark && vfsmount_mark) {
332 int cmp = fsnotify_compare_groups(inode_mark->group,
333 vfsmount_mark->group);
334 if (cmp > 0)
335 inode_mark = NULL;
336 else if (cmp < 0)
337 vfsmount_mark = NULL;
338 }
339
340 ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask,
341 data, data_is, cookie, file_name,
342 &iter_info);
343
344 if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
345 goto out;
346
347 if (inode_mark)
348 iter_info.inode_mark =
349 fsnotify_next_mark(iter_info.inode_mark);
350 if (vfsmount_mark)
351 iter_info.vfsmount_mark =
352 fsnotify_next_mark(iter_info.vfsmount_mark);
353 }
354 ret = 0;
355out:
356 srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx);
357
358 return ret;
359}
360EXPORT_SYMBOL_GPL(fsnotify);
361
362extern struct kmem_cache *fsnotify_mark_connector_cachep;
363
364static __init int fsnotify_init(void)
365{
366 int ret;
367
368 BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
369
370 ret = init_srcu_struct(&fsnotify_mark_srcu);
371 if (ret)
372 panic("initializing fsnotify_mark_srcu");
373
374 fsnotify_mark_connector_cachep = KMEM_CACHE(fsnotify_mark_connector,
375 SLAB_PANIC);
376
377 return 0;
378}
379core_initcall(fsnotify_init);
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#include <linux/dcache.h>
20#include <linux/fs.h>
21#include <linux/gfp.h>
22#include <linux/init.h>
23#include <linux/module.h>
24#include <linux/mount.h>
25#include <linux/srcu.h>
26
27#include <linux/fsnotify_backend.h>
28#include "fsnotify.h"
29
30/*
31 * Clear all of the marks on an inode when it is being evicted from core
32 */
33void __fsnotify_inode_delete(struct inode *inode)
34{
35 fsnotify_clear_marks_by_inode(inode);
36}
37EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
38
39void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
40{
41 fsnotify_clear_marks_by_mount(mnt);
42}
43
44/*
45 * Given an inode, first check if we care what happens to our children. Inotify
46 * and dnotify both tell their parents about events. If we care about any event
47 * on a child we run all of our children and set a dentry flag saying that the
48 * parent cares. Thus when an event happens on a child it can quickly tell if
49 * if there is a need to find a parent and send the event to the parent.
50 */
51void __fsnotify_update_child_dentry_flags(struct inode *inode)
52{
53 struct dentry *alias;
54 int watched;
55
56 if (!S_ISDIR(inode->i_mode))
57 return;
58
59 /* determine if the children should tell inode about their events */
60 watched = fsnotify_inode_watches_children(inode);
61
62 spin_lock(&inode->i_lock);
63 /* run all of the dentries associated with this inode. Since this is a
64 * directory, there damn well better only be one item on this list */
65 list_for_each_entry(alias, &inode->i_dentry, d_alias) {
66 struct dentry *child;
67
68 /* run all of the children of the original inode and fix their
69 * d_flags to indicate parental interest (their parent is the
70 * original inode) */
71 spin_lock(&alias->d_lock);
72 list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
73 if (!child->d_inode)
74 continue;
75
76 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
77 if (watched)
78 child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
79 else
80 child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
81 spin_unlock(&child->d_lock);
82 }
83 spin_unlock(&alias->d_lock);
84 }
85 spin_unlock(&inode->i_lock);
86}
87
88/* Notify this dentry's parent about a child's events. */
89int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
90{
91 struct dentry *parent;
92 struct inode *p_inode;
93 int ret = 0;
94
95 if (!dentry)
96 dentry = path->dentry;
97
98 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
99 return 0;
100
101 parent = dget_parent(dentry);
102 p_inode = parent->d_inode;
103
104 if (unlikely(!fsnotify_inode_watches_children(p_inode)))
105 __fsnotify_update_child_dentry_flags(p_inode);
106 else if (p_inode->i_fsnotify_mask & mask) {
107 /* we are notifying a parent so come up with the new mask which
108 * specifies these are events which came from a child. */
109 mask |= FS_EVENT_ON_CHILD;
110
111 if (path)
112 ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
113 dentry->d_name.name, 0);
114 else
115 ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
116 dentry->d_name.name, 0);
117 }
118
119 dput(parent);
120
121 return ret;
122}
123EXPORT_SYMBOL_GPL(__fsnotify_parent);
124
125static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
126 struct fsnotify_mark *inode_mark,
127 struct fsnotify_mark *vfsmount_mark,
128 __u32 mask, void *data,
129 int data_is, u32 cookie,
130 const unsigned char *file_name,
131 struct fsnotify_event **event)
132{
133 struct fsnotify_group *group = NULL;
134 __u32 inode_test_mask = 0;
135 __u32 vfsmount_test_mask = 0;
136
137 if (unlikely(!inode_mark && !vfsmount_mark)) {
138 BUG();
139 return 0;
140 }
141
142 /* clear ignored on inode modification */
143 if (mask & FS_MODIFY) {
144 if (inode_mark &&
145 !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
146 inode_mark->ignored_mask = 0;
147 if (vfsmount_mark &&
148 !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
149 vfsmount_mark->ignored_mask = 0;
150 }
151
152 /* does the inode mark tell us to do something? */
153 if (inode_mark) {
154 group = inode_mark->group;
155 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
156 inode_test_mask &= inode_mark->mask;
157 inode_test_mask &= ~inode_mark->ignored_mask;
158 }
159
160 /* does the vfsmount_mark tell us to do something? */
161 if (vfsmount_mark) {
162 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
163 group = vfsmount_mark->group;
164 vfsmount_test_mask &= vfsmount_mark->mask;
165 vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
166 if (inode_mark)
167 vfsmount_test_mask &= ~inode_mark->ignored_mask;
168 }
169
170 pr_debug("%s: group=%p to_tell=%p mnt=%p mask=%x inode_mark=%p"
171 " inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
172 " data=%p data_is=%d cookie=%d event=%p\n",
173 __func__, group, to_tell, mnt, mask, inode_mark,
174 inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
175 data_is, cookie, *event);
176
177 if (!inode_test_mask && !vfsmount_test_mask)
178 return 0;
179
180 if (group->ops->should_send_event(group, to_tell, inode_mark,
181 vfsmount_mark, mask, data,
182 data_is) == false)
183 return 0;
184
185 if (!*event) {
186 *event = fsnotify_create_event(to_tell, mask, data,
187 data_is, file_name,
188 cookie, GFP_KERNEL);
189 if (!*event)
190 return -ENOMEM;
191 }
192 return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event);
193}
194
195/*
196 * This is the main call to fsnotify. The VFS calls into hook specific functions
197 * in linux/fsnotify.h. Those functions then in turn call here. Here will call
198 * out to all of the registered fsnotify_group. Those groups can then use the
199 * notification event in whatever means they feel necessary.
200 */
201int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
202 const unsigned char *file_name, u32 cookie)
203{
204 struct hlist_node *inode_node = NULL, *vfsmount_node = NULL;
205 struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
206 struct fsnotify_group *inode_group, *vfsmount_group;
207 struct fsnotify_event *event = NULL;
208 struct vfsmount *mnt;
209 int idx, ret = 0;
210 /* global tests shouldn't care about events on child only the specific event */
211 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
212
213 if (data_is == FSNOTIFY_EVENT_PATH)
214 mnt = ((struct path *)data)->mnt;
215 else
216 mnt = NULL;
217
218 /*
219 * if this is a modify event we may need to clear the ignored masks
220 * otherwise return if neither the inode nor the vfsmount care about
221 * this type of event.
222 */
223 if (!(mask & FS_MODIFY) &&
224 !(test_mask & to_tell->i_fsnotify_mask) &&
225 !(mnt && test_mask & mnt->mnt_fsnotify_mask))
226 return 0;
227
228 idx = srcu_read_lock(&fsnotify_mark_srcu);
229
230 if ((mask & FS_MODIFY) ||
231 (test_mask & to_tell->i_fsnotify_mask))
232 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
233 &fsnotify_mark_srcu);
234
235 if (mnt && ((mask & FS_MODIFY) ||
236 (test_mask & mnt->mnt_fsnotify_mask))) {
237 vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
238 &fsnotify_mark_srcu);
239 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
240 &fsnotify_mark_srcu);
241 }
242
243 while (inode_node || vfsmount_node) {
244 inode_group = vfsmount_group = NULL;
245
246 if (inode_node) {
247 inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
248 struct fsnotify_mark, i.i_list);
249 inode_group = inode_mark->group;
250 }
251
252 if (vfsmount_node) {
253 vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
254 struct fsnotify_mark, m.m_list);
255 vfsmount_group = vfsmount_mark->group;
256 }
257
258 if (inode_group > vfsmount_group) {
259 /* handle inode */
260 ret = send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
261 data_is, cookie, file_name, &event);
262 /* we didn't use the vfsmount_mark */
263 vfsmount_group = NULL;
264 } else if (vfsmount_group > inode_group) {
265 ret = send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
266 data_is, cookie, file_name, &event);
267 inode_group = NULL;
268 } else {
269 ret = send_to_group(to_tell, mnt, inode_mark, vfsmount_mark,
270 mask, data, data_is, cookie, file_name,
271 &event);
272 }
273
274 if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
275 goto out;
276
277 if (inode_group)
278 inode_node = srcu_dereference(inode_node->next,
279 &fsnotify_mark_srcu);
280 if (vfsmount_group)
281 vfsmount_node = srcu_dereference(vfsmount_node->next,
282 &fsnotify_mark_srcu);
283 }
284 ret = 0;
285out:
286 srcu_read_unlock(&fsnotify_mark_srcu, idx);
287 /*
288 * fsnotify_create_event() took a reference so the event can't be cleaned
289 * up while we are still trying to add it to lists, drop that one.
290 */
291 if (event)
292 fsnotify_put_event(event);
293
294 return ret;
295}
296EXPORT_SYMBOL_GPL(fsnotify);
297
298static __init int fsnotify_init(void)
299{
300 int ret;
301
302 BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
303
304 ret = init_srcu_struct(&fsnotify_mark_srcu);
305 if (ret)
306 panic("initializing fsnotify_mark_srcu");
307
308 return 0;
309}
310core_initcall(fsnotify_init);