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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
30
31
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
46
47
48
49
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
60 watched = fsnotify_inode_watches_children(inode);
61
62 spin_lock(&inode->i_lock);
63
64
65 list_for_each_entry(alias, &inode->i_dentry, d_alias) {
66 struct dentry *child;
67
68
69
70
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
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
108
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
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
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
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
197
198
199
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
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
220
221
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
260 ret = send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
261 data_is, cookie, file_name, &event);
262
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
289
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);
311