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6#include <linux/dcache.h>
7#include <linux/fs.h>
8#include <linux/gfp.h>
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/mount.h>
12#include <linux/srcu.h>
13
14#include <linux/fsnotify_backend.h>
15#include "fsnotify.h"
16
17
18
19
20void __fsnotify_inode_delete(struct inode *inode)
21{
22 fsnotify_clear_marks_by_inode(inode);
23}
24EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
25
26void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
27{
28 fsnotify_clear_marks_by_mount(mnt);
29}
30
31
32
33
34
35
36
37
38static void fsnotify_unmount_inodes(struct super_block *sb)
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
46
47
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
57
58
59
60
61 if (!atomic_read(&inode->i_count)) {
62 spin_unlock(&inode->i_lock);
63 continue;
64 }
65
66 __iget(inode);
67 spin_unlock(&inode->i_lock);
68 spin_unlock(&sb->s_inode_list_lock);
69
70 if (iput_inode)
71 iput(iput_inode);
72
73
74 fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
75
76 fsnotify_inode_delete(inode);
77
78 iput_inode = inode;
79
80 spin_lock(&sb->s_inode_list_lock);
81 }
82 spin_unlock(&sb->s_inode_list_lock);
83
84 if (iput_inode)
85 iput(iput_inode);
86
87 wait_var_event(&sb->s_fsnotify_inode_refs,
88 !atomic_long_read(&sb->s_fsnotify_inode_refs));
89}
90
91void fsnotify_sb_delete(struct super_block *sb)
92{
93 fsnotify_unmount_inodes(sb);
94 fsnotify_clear_marks_by_sb(sb);
95}
96
97
98
99
100
101
102
103
104void __fsnotify_update_child_dentry_flags(struct inode *inode)
105{
106 struct dentry *alias;
107 int watched;
108
109 if (!S_ISDIR(inode->i_mode))
110 return;
111
112
113 watched = fsnotify_inode_watches_children(inode);
114
115 spin_lock(&inode->i_lock);
116
117
118 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
119 struct dentry *child;
120
121
122
123
124 spin_lock(&alias->d_lock);
125 list_for_each_entry(child, &alias->d_subdirs, d_child) {
126 if (!child->d_inode)
127 continue;
128
129 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
130 if (watched)
131 child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
132 else
133 child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
134 spin_unlock(&child->d_lock);
135 }
136 spin_unlock(&alias->d_lock);
137 }
138 spin_unlock(&inode->i_lock);
139}
140
141
142int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask)
143{
144 struct dentry *parent;
145 struct inode *p_inode;
146 int ret = 0;
147
148 if (!dentry)
149 dentry = path->dentry;
150
151 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
152 return 0;
153
154 parent = dget_parent(dentry);
155 p_inode = parent->d_inode;
156
157 if (unlikely(!fsnotify_inode_watches_children(p_inode))) {
158 __fsnotify_update_child_dentry_flags(p_inode);
159 } else if (p_inode->i_fsnotify_mask & mask & ALL_FSNOTIFY_EVENTS) {
160 struct name_snapshot name;
161
162
163
164 mask |= FS_EVENT_ON_CHILD;
165
166 take_dentry_name_snapshot(&name, dentry);
167 if (path)
168 ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
169 &name.name, 0);
170 else
171 ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
172 &name.name, 0);
173 release_dentry_name_snapshot(&name);
174 }
175
176 dput(parent);
177
178 return ret;
179}
180EXPORT_SYMBOL_GPL(__fsnotify_parent);
181
182static int send_to_group(struct inode *to_tell,
183 __u32 mask, const void *data,
184 int data_is, u32 cookie,
185 const struct qstr *file_name,
186 struct fsnotify_iter_info *iter_info)
187{
188 struct fsnotify_group *group = NULL;
189 __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
190 __u32 marks_mask = 0;
191 __u32 marks_ignored_mask = 0;
192 struct fsnotify_mark *mark;
193 int type;
194
195 if (WARN_ON(!iter_info->report_mask))
196 return 0;
197
198
199 if (mask & FS_MODIFY) {
200 fsnotify_foreach_obj_type(type) {
201 if (!fsnotify_iter_should_report_type(iter_info, type))
202 continue;
203 mark = iter_info->marks[type];
204 if (mark &&
205 !(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
206 mark->ignored_mask = 0;
207 }
208 }
209
210 fsnotify_foreach_obj_type(type) {
211 if (!fsnotify_iter_should_report_type(iter_info, type))
212 continue;
213 mark = iter_info->marks[type];
214
215 if (mark) {
216 group = mark->group;
217 marks_mask |= mark->mask;
218 marks_ignored_mask |= mark->ignored_mask;
219 }
220 }
221
222 pr_debug("%s: group=%p to_tell=%p mask=%x marks_mask=%x marks_ignored_mask=%x"
223 " data=%p data_is=%d cookie=%d\n",
224 __func__, group, to_tell, mask, marks_mask, marks_ignored_mask,
225 data, data_is, cookie);
226
227 if (!(test_mask & marks_mask & ~marks_ignored_mask))
228 return 0;
229
230 return group->ops->handle_event(group, to_tell, mask, data, data_is,
231 file_name, cookie, iter_info);
232}
233
234static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp)
235{
236 struct fsnotify_mark_connector *conn;
237 struct hlist_node *node = NULL;
238
239 conn = srcu_dereference(*connp, &fsnotify_mark_srcu);
240 if (conn)
241 node = srcu_dereference(conn->list.first, &fsnotify_mark_srcu);
242
243 return hlist_entry_safe(node, struct fsnotify_mark, obj_list);
244}
245
246static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark)
247{
248 struct hlist_node *node = NULL;
249
250 if (mark)
251 node = srcu_dereference(mark->obj_list.next,
252 &fsnotify_mark_srcu);
253
254 return hlist_entry_safe(node, struct fsnotify_mark, obj_list);
255}
256
257
258
259
260
261
262
263static unsigned int fsnotify_iter_select_report_types(
264 struct fsnotify_iter_info *iter_info)
265{
266 struct fsnotify_group *max_prio_group = NULL;
267 struct fsnotify_mark *mark;
268 int type;
269
270
271 fsnotify_foreach_obj_type(type) {
272 mark = iter_info->marks[type];
273 if (mark &&
274 fsnotify_compare_groups(max_prio_group, mark->group) > 0)
275 max_prio_group = mark->group;
276 }
277
278 if (!max_prio_group)
279 return 0;
280
281
282 iter_info->report_mask = 0;
283 fsnotify_foreach_obj_type(type) {
284 mark = iter_info->marks[type];
285 if (mark &&
286 fsnotify_compare_groups(max_prio_group, mark->group) == 0)
287 fsnotify_iter_set_report_type(iter_info, type);
288 }
289
290 return iter_info->report_mask;
291}
292
293
294
295
296
297static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info)
298{
299 int type;
300
301 fsnotify_foreach_obj_type(type) {
302 if (fsnotify_iter_should_report_type(iter_info, type))
303 iter_info->marks[type] =
304 fsnotify_next_mark(iter_info->marks[type]);
305 }
306}
307
308
309
310
311
312
313
314int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
315 const struct qstr *file_name, u32 cookie)
316{
317 struct fsnotify_iter_info iter_info = {};
318 struct super_block *sb = to_tell->i_sb;
319 struct mount *mnt = NULL;
320 __u32 mnt_or_sb_mask = sb->s_fsnotify_mask;
321 int ret = 0;
322 __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
323
324 if (data_is == FSNOTIFY_EVENT_PATH) {
325 mnt = real_mount(((const struct path *)data)->mnt);
326 mnt_or_sb_mask |= mnt->mnt_fsnotify_mask;
327 }
328
329 if (mask & FS_EVENT_ON_CHILD)
330 mnt_or_sb_mask = 0;
331
332
333
334
335
336
337
338
339 if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks &&
340 (!mnt || !mnt->mnt_fsnotify_marks))
341 return 0;
342
343
344
345
346
347 if (!(mask & FS_MODIFY) &&
348 !(test_mask & (to_tell->i_fsnotify_mask | mnt_or_sb_mask)))
349 return 0;
350
351 iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
352
353 iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] =
354 fsnotify_first_mark(&to_tell->i_fsnotify_marks);
355 iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] =
356 fsnotify_first_mark(&sb->s_fsnotify_marks);
357 if (mnt) {
358 iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] =
359 fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
360 }
361
362
363
364
365
366
367 while (fsnotify_iter_select_report_types(&iter_info)) {
368 ret = send_to_group(to_tell, mask, data, data_is, cookie,
369 file_name, &iter_info);
370
371 if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
372 goto out;
373
374 fsnotify_iter_next(&iter_info);
375 }
376 ret = 0;
377out:
378 srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx);
379
380 return ret;
381}
382EXPORT_SYMBOL_GPL(fsnotify);
383
384extern struct kmem_cache *fsnotify_mark_connector_cachep;
385
386static __init int fsnotify_init(void)
387{
388 int ret;
389
390 BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 25);
391
392 ret = init_srcu_struct(&fsnotify_mark_srcu);
393 if (ret)
394 panic("initializing fsnotify_mark_srcu");
395
396 fsnotify_mark_connector_cachep = KMEM_CACHE(fsnotify_mark_connector,
397 SLAB_PANIC);
398
399 return 0;
400}
401core_initcall(fsnotify_init);
402