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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#include "../mount.h"
30
31
32
33
34void __fsnotify_inode_delete(struct inode *inode)
35{
36 fsnotify_clear_marks_by_inode(inode);
37}
38EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
39
40void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
41{
42 fsnotify_clear_marks_by_mount(mnt);
43}
44
45
46
47
48
49
50
51
52void __fsnotify_update_child_dentry_flags(struct inode *inode)
53{
54 struct dentry *alias;
55 int watched;
56
57 if (!S_ISDIR(inode->i_mode))
58 return;
59
60
61 watched = fsnotify_inode_watches_children(inode);
62
63 spin_lock(&inode->i_lock);
64
65
66 hlist_for_each_entry(alias, &inode->i_dentry, d_alias) {
67 struct dentry *child;
68
69
70
71
72 spin_lock(&alias->d_lock);
73 list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
74 if (!child->d_inode)
75 continue;
76
77 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
78 if (watched)
79 child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
80 else
81 child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
82 spin_unlock(&child->d_lock);
83 }
84 spin_unlock(&alias->d_lock);
85 }
86 spin_unlock(&inode->i_lock);
87}
88
89
90int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
91{
92 struct dentry *parent;
93 struct inode *p_inode;
94 int ret = 0;
95
96 if (!dentry)
97 dentry = path->dentry;
98
99 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
100 return 0;
101
102 parent = dget_parent(dentry);
103 p_inode = parent->d_inode;
104
105 if (unlikely(!fsnotify_inode_watches_children(p_inode)))
106 __fsnotify_update_child_dentry_flags(p_inode);
107 else if (p_inode->i_fsnotify_mask & mask) {
108
109
110 mask |= FS_EVENT_ON_CHILD;
111
112 if (path)
113 ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
114 dentry->d_name.name, 0);
115 else
116 ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
117 dentry->d_name.name, 0);
118 }
119
120 dput(parent);
121
122 return ret;
123}
124EXPORT_SYMBOL_GPL(__fsnotify_parent);
125
126static int send_to_group(struct inode *to_tell,
127 struct fsnotify_mark *inode_mark,
128 struct fsnotify_mark *vfsmount_mark,
129 __u32 mask, void *data,
130 int data_is, u32 cookie,
131 const unsigned char *file_name,
132 struct fsnotify_event **event)
133{
134 struct fsnotify_group *group = NULL;
135 __u32 inode_test_mask = 0;
136 __u32 vfsmount_test_mask = 0;
137
138 if (unlikely(!inode_mark && !vfsmount_mark)) {
139 BUG();
140 return 0;
141 }
142
143
144 if (mask & FS_MODIFY) {
145 if (inode_mark &&
146 !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
147 inode_mark->ignored_mask = 0;
148 if (vfsmount_mark &&
149 !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
150 vfsmount_mark->ignored_mask = 0;
151 }
152
153
154 if (inode_mark) {
155 group = inode_mark->group;
156 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
157 inode_test_mask &= inode_mark->mask;
158 inode_test_mask &= ~inode_mark->ignored_mask;
159 }
160
161
162 if (vfsmount_mark) {
163 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
164 group = vfsmount_mark->group;
165 vfsmount_test_mask &= vfsmount_mark->mask;
166 vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
167 if (inode_mark)
168 vfsmount_test_mask &= ~inode_mark->ignored_mask;
169 }
170
171 pr_debug("%s: group=%p to_tell=%p mask=%x inode_mark=%p"
172 " inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
173 " data=%p data_is=%d cookie=%d event=%p\n",
174 __func__, group, to_tell, mask, inode_mark,
175 inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
176 data_is, cookie, *event);
177
178 if (!inode_test_mask && !vfsmount_test_mask)
179 return 0;
180
181 if (group->ops->should_send_event(group, to_tell, inode_mark,
182 vfsmount_mark, mask, data,
183 data_is) == false)
184 return 0;
185
186 if (!*event) {
187 *event = fsnotify_create_event(to_tell, mask, data,
188 data_is, file_name,
189 cookie, GFP_KERNEL);
190 if (!*event)
191 return -ENOMEM;
192 }
193 return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event);
194}
195
196
197
198
199
200
201
202int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
203 const unsigned char *file_name, u32 cookie)
204{
205 struct hlist_node *inode_node = NULL, *vfsmount_node = NULL;
206 struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
207 struct fsnotify_group *inode_group, *vfsmount_group;
208 struct fsnotify_event *event = NULL;
209 struct mount *mnt;
210 int idx, ret = 0;
211
212 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
213
214 if (data_is == FSNOTIFY_EVENT_PATH)
215 mnt = real_mount(((struct path *)data)->mnt);
216 else
217 mnt = NULL;
218
219
220
221
222
223
224 if (!(mask & FS_MODIFY) &&
225 !(test_mask & to_tell->i_fsnotify_mask) &&
226 !(mnt && test_mask & mnt->mnt_fsnotify_mask))
227 return 0;
228
229 idx = srcu_read_lock(&fsnotify_mark_srcu);
230
231 if ((mask & FS_MODIFY) ||
232 (test_mask & to_tell->i_fsnotify_mask))
233 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
234 &fsnotify_mark_srcu);
235
236 if (mnt && ((mask & FS_MODIFY) ||
237 (test_mask & mnt->mnt_fsnotify_mask))) {
238 vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
239 &fsnotify_mark_srcu);
240 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
241 &fsnotify_mark_srcu);
242 }
243
244 while (inode_node || vfsmount_node) {
245 inode_group = vfsmount_group = NULL;
246
247 if (inode_node) {
248 inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
249 struct fsnotify_mark, i.i_list);
250 inode_group = inode_mark->group;
251 }
252
253 if (vfsmount_node) {
254 vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
255 struct fsnotify_mark, m.m_list);
256 vfsmount_group = vfsmount_mark->group;
257 }
258
259 if (inode_group > vfsmount_group) {
260
261 ret = send_to_group(to_tell, inode_mark, NULL, mask, data,
262 data_is, cookie, file_name, &event);
263
264 vfsmount_group = NULL;
265 } else if (vfsmount_group > inode_group) {
266 ret = send_to_group(to_tell, NULL, vfsmount_mark, mask, data,
267 data_is, cookie, file_name, &event);
268 inode_group = NULL;
269 } else {
270 ret = send_to_group(to_tell, inode_mark, vfsmount_mark,
271 mask, data, data_is, cookie, file_name,
272 &event);
273 }
274
275 if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
276 goto out;
277
278 if (inode_group)
279 inode_node = srcu_dereference(inode_node->next,
280 &fsnotify_mark_srcu);
281 if (vfsmount_group)
282 vfsmount_node = srcu_dereference(vfsmount_node->next,
283 &fsnotify_mark_srcu);
284 }
285 ret = 0;
286out:
287 srcu_read_unlock(&fsnotify_mark_srcu, idx);
288
289
290
291
292 if (event)
293 fsnotify_put_event(event);
294
295 return ret;
296}
297EXPORT_SYMBOL_GPL(fsnotify);
298
299static __init int fsnotify_init(void)
300{
301 int ret;
302
303 BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
304
305 ret = init_srcu_struct(&fsnotify_mark_srcu);
306 if (ret)
307 panic("initializing fsnotify_mark_srcu");
308
309 return 0;
310}
311core_initcall(fsnotify_init);
312