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90586523 EP |
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> | |
5a0e3ad6 | 21 | #include <linux/gfp.h> |
90586523 EP |
22 | #include <linux/init.h> |
23 | #include <linux/module.h> | |
7131485a | 24 | #include <linux/mount.h> |
90586523 EP |
25 | #include <linux/srcu.h> |
26 | ||
27 | #include <linux/fsnotify_backend.h> | |
28 | #include "fsnotify.h" | |
c63181e6 | 29 | #include "../mount.h" |
90586523 | 30 | |
3be25f49 EP |
31 | /* |
32 | * Clear all of the marks on an inode when it is being evicted from core | |
33 | */ | |
34 | void __fsnotify_inode_delete(struct inode *inode) | |
35 | { | |
36 | fsnotify_clear_marks_by_inode(inode); | |
37 | } | |
38 | EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); | |
39 | ||
ca9c726e AG |
40 | void __fsnotify_vfsmount_delete(struct vfsmount *mnt) |
41 | { | |
42 | fsnotify_clear_marks_by_mount(mnt); | |
43 | } | |
44 | ||
c28f7e56 EP |
45 | /* |
46 | * Given an inode, first check if we care what happens to our children. Inotify | |
47 | * and dnotify both tell their parents about events. If we care about any event | |
48 | * on a child we run all of our children and set a dentry flag saying that the | |
49 | * parent cares. Thus when an event happens on a child it can quickly tell if | |
50 | * if there is a need to find a parent and send the event to the parent. | |
51 | */ | |
52 | void __fsnotify_update_child_dentry_flags(struct inode *inode) | |
53 | { | |
54 | struct dentry *alias; | |
b3d9b7a3 | 55 | struct hlist_node *p; |
c28f7e56 EP |
56 | int watched; |
57 | ||
58 | if (!S_ISDIR(inode->i_mode)) | |
59 | return; | |
60 | ||
61 | /* determine if the children should tell inode about their events */ | |
62 | watched = fsnotify_inode_watches_children(inode); | |
63 | ||
873feea0 | 64 | spin_lock(&inode->i_lock); |
c28f7e56 EP |
65 | /* run all of the dentries associated with this inode. Since this is a |
66 | * directory, there damn well better only be one item on this list */ | |
b3d9b7a3 | 67 | hlist_for_each_entry(alias, p, &inode->i_dentry, d_alias) { |
c28f7e56 EP |
68 | struct dentry *child; |
69 | ||
70 | /* run all of the children of the original inode and fix their | |
71 | * d_flags to indicate parental interest (their parent is the | |
72 | * original inode) */ | |
2fd6b7f5 | 73 | spin_lock(&alias->d_lock); |
c28f7e56 EP |
74 | list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { |
75 | if (!child->d_inode) | |
76 | continue; | |
77 | ||
2fd6b7f5 | 78 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
c28f7e56 EP |
79 | if (watched) |
80 | child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; | |
81 | else | |
82 | child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; | |
83 | spin_unlock(&child->d_lock); | |
84 | } | |
2fd6b7f5 | 85 | spin_unlock(&alias->d_lock); |
c28f7e56 | 86 | } |
873feea0 | 87 | spin_unlock(&inode->i_lock); |
c28f7e56 EP |
88 | } |
89 | ||
90 | /* Notify this dentry's parent about a child's events. */ | |
52420392 | 91 | int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask) |
c28f7e56 EP |
92 | { |
93 | struct dentry *parent; | |
94 | struct inode *p_inode; | |
52420392 | 95 | int ret = 0; |
c28f7e56 | 96 | |
72acc854 | 97 | if (!dentry) |
2069601b | 98 | dentry = path->dentry; |
28c60e37 | 99 | |
c28f7e56 | 100 | if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) |
52420392 | 101 | return 0; |
c28f7e56 | 102 | |
4d4eb366 | 103 | parent = dget_parent(dentry); |
c28f7e56 EP |
104 | p_inode = parent->d_inode; |
105 | ||
4d4eb366 CH |
106 | if (unlikely(!fsnotify_inode_watches_children(p_inode))) |
107 | __fsnotify_update_child_dentry_flags(p_inode); | |
108 | else if (p_inode->i_fsnotify_mask & mask) { | |
c28f7e56 EP |
109 | /* we are notifying a parent so come up with the new mask which |
110 | * specifies these are events which came from a child. */ | |
111 | mask |= FS_EVENT_ON_CHILD; | |
112 | ||
2069601b | 113 | if (path) |
52420392 EP |
114 | ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH, |
115 | dentry->d_name.name, 0); | |
28c60e37 | 116 | else |
52420392 EP |
117 | ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, |
118 | dentry->d_name.name, 0); | |
c28f7e56 EP |
119 | } |
120 | ||
4d4eb366 | 121 | dput(parent); |
52420392 EP |
122 | |
123 | return ret; | |
c28f7e56 EP |
124 | } |
125 | EXPORT_SYMBOL_GPL(__fsnotify_parent); | |
126 | ||
fd657170 | 127 | static int send_to_group(struct inode *to_tell, |
ce8f76fb EP |
128 | struct fsnotify_mark *inode_mark, |
129 | struct fsnotify_mark *vfsmount_mark, | |
130 | __u32 mask, void *data, | |
613a807f | 131 | int data_is, u32 cookie, |
3a9b16b4 | 132 | const unsigned char *file_name, |
c4ec54b4 | 133 | struct fsnotify_event **event) |
7131485a | 134 | { |
faa9560a | 135 | struct fsnotify_group *group = NULL; |
84e1ab4d EP |
136 | __u32 inode_test_mask = 0; |
137 | __u32 vfsmount_test_mask = 0; | |
613a807f | 138 | |
faa9560a EP |
139 | if (unlikely(!inode_mark && !vfsmount_mark)) { |
140 | BUG(); | |
141 | return 0; | |
142 | } | |
ce8f76fb EP |
143 | |
144 | /* clear ignored on inode modification */ | |
145 | if (mask & FS_MODIFY) { | |
146 | if (inode_mark && | |
147 | !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) | |
148 | inode_mark->ignored_mask = 0; | |
149 | if (vfsmount_mark && | |
150 | !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) | |
151 | vfsmount_mark->ignored_mask = 0; | |
152 | } | |
5ba08e2e | 153 | |
ce8f76fb EP |
154 | /* does the inode mark tell us to do something? */ |
155 | if (inode_mark) { | |
faa9560a | 156 | group = inode_mark->group; |
84e1ab4d | 157 | inode_test_mask = (mask & ~FS_EVENT_ON_CHILD); |
ce8f76fb EP |
158 | inode_test_mask &= inode_mark->mask; |
159 | inode_test_mask &= ~inode_mark->ignored_mask; | |
160 | } | |
613a807f | 161 | |
ce8f76fb EP |
162 | /* does the vfsmount_mark tell us to do something? */ |
163 | if (vfsmount_mark) { | |
84e1ab4d | 164 | vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD); |
faa9560a | 165 | group = vfsmount_mark->group; |
ce8f76fb EP |
166 | vfsmount_test_mask &= vfsmount_mark->mask; |
167 | vfsmount_test_mask &= ~vfsmount_mark->ignored_mask; | |
168 | if (inode_mark) | |
169 | vfsmount_test_mask &= ~inode_mark->ignored_mask; | |
170 | } | |
171 | ||
fd657170 | 172 | pr_debug("%s: group=%p to_tell=%p mask=%x inode_mark=%p" |
84e1ab4d EP |
173 | " inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x" |
174 | " data=%p data_is=%d cookie=%d event=%p\n", | |
fd657170 | 175 | __func__, group, to_tell, mask, inode_mark, |
84e1ab4d EP |
176 | inode_test_mask, vfsmount_mark, vfsmount_test_mask, data, |
177 | data_is, cookie, *event); | |
faa9560a | 178 | |
ce8f76fb | 179 | if (!inode_test_mask && !vfsmount_test_mask) |
613a807f EP |
180 | return 0; |
181 | ||
1968f5ee | 182 | if (group->ops->should_send_event(group, to_tell, inode_mark, |
ce8f76fb EP |
183 | vfsmount_mark, mask, data, |
184 | data_is) == false) | |
c4ec54b4 | 185 | return 0; |
613a807f | 186 | |
7131485a EP |
187 | if (!*event) { |
188 | *event = fsnotify_create_event(to_tell, mask, data, | |
189 | data_is, file_name, | |
190 | cookie, GFP_KERNEL); | |
7131485a | 191 | if (!*event) |
c4ec54b4 | 192 | return -ENOMEM; |
7131485a | 193 | } |
ce8f76fb | 194 | return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event); |
7131485a EP |
195 | } |
196 | ||
90586523 EP |
197 | /* |
198 | * This is the main call to fsnotify. The VFS calls into hook specific functions | |
199 | * in linux/fsnotify.h. Those functions then in turn call here. Here will call | |
200 | * out to all of the registered fsnotify_group. Those groups can then use the | |
201 | * notification event in whatever means they feel necessary. | |
202 | */ | |
c4ec54b4 EP |
203 | int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, |
204 | const unsigned char *file_name, u32 cookie) | |
90586523 | 205 | { |
84e1ab4d | 206 | struct hlist_node *inode_node = NULL, *vfsmount_node = NULL; |
613a807f EP |
207 | struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL; |
208 | struct fsnotify_group *inode_group, *vfsmount_group; | |
90586523 | 209 | struct fsnotify_event *event = NULL; |
c63181e6 | 210 | struct mount *mnt; |
c4ec54b4 | 211 | int idx, ret = 0; |
e42e2773 EP |
212 | /* global tests shouldn't care about events on child only the specific event */ |
213 | __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD); | |
90586523 | 214 | |
2069601b | 215 | if (data_is == FSNOTIFY_EVENT_PATH) |
c63181e6 | 216 | mnt = real_mount(((struct path *)data)->mnt); |
613a807f EP |
217 | else |
218 | mnt = NULL; | |
219 | ||
220 | /* | |
221 | * if this is a modify event we may need to clear the ignored masks | |
222 | * otherwise return if neither the inode nor the vfsmount care about | |
223 | * this type of event. | |
224 | */ | |
225 | if (!(mask & FS_MODIFY) && | |
226 | !(test_mask & to_tell->i_fsnotify_mask) && | |
227 | !(mnt && test_mask & mnt->mnt_fsnotify_mask)) | |
228 | return 0; | |
3a9fb89f | 229 | |
75c1be48 | 230 | idx = srcu_read_lock(&fsnotify_mark_srcu); |
7131485a | 231 | |
613a807f EP |
232 | if ((mask & FS_MODIFY) || |
233 | (test_mask & to_tell->i_fsnotify_mask)) | |
ce8f76fb EP |
234 | inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first, |
235 | &fsnotify_mark_srcu); | |
613a807f | 236 | |
84e1ab4d EP |
237 | if (mnt && ((mask & FS_MODIFY) || |
238 | (test_mask & mnt->mnt_fsnotify_mask))) { | |
239 | vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first, | |
240 | &fsnotify_mark_srcu); | |
241 | inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first, | |
242 | &fsnotify_mark_srcu); | |
90586523 | 243 | } |
75c1be48 | 244 | |
613a807f | 245 | while (inode_node || vfsmount_node) { |
f72adfd5 | 246 | inode_group = vfsmount_group = NULL; |
5f3f259f | 247 | |
613a807f EP |
248 | if (inode_node) { |
249 | inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu), | |
250 | struct fsnotify_mark, i.i_list); | |
251 | inode_group = inode_mark->group; | |
f72adfd5 | 252 | } |
613a807f EP |
253 | |
254 | if (vfsmount_node) { | |
255 | vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu), | |
256 | struct fsnotify_mark, m.m_list); | |
257 | vfsmount_group = vfsmount_mark->group; | |
f72adfd5 | 258 | } |
613a807f | 259 | |
f72adfd5 | 260 | if (inode_group > vfsmount_group) { |
613a807f | 261 | /* handle inode */ |
fd657170 | 262 | ret = send_to_group(to_tell, inode_mark, NULL, mask, data, |
ff8bcbd0 | 263 | data_is, cookie, file_name, &event); |
92b4678e EP |
264 | /* we didn't use the vfsmount_mark */ |
265 | vfsmount_group = NULL; | |
f72adfd5 | 266 | } else if (vfsmount_group > inode_group) { |
fd657170 | 267 | ret = send_to_group(to_tell, NULL, vfsmount_mark, mask, data, |
ff8bcbd0 | 268 | data_is, cookie, file_name, &event); |
92b4678e | 269 | inode_group = NULL; |
613a807f | 270 | } else { |
fd657170 | 271 | ret = send_to_group(to_tell, inode_mark, vfsmount_mark, |
ff8bcbd0 EP |
272 | mask, data, data_is, cookie, file_name, |
273 | &event); | |
7131485a | 274 | } |
613a807f | 275 | |
ff8bcbd0 EP |
276 | if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) |
277 | goto out; | |
278 | ||
92b4678e | 279 | if (inode_group) |
ce8f76fb EP |
280 | inode_node = srcu_dereference(inode_node->next, |
281 | &fsnotify_mark_srcu); | |
92b4678e | 282 | if (vfsmount_group) |
ce8f76fb EP |
283 | vfsmount_node = srcu_dereference(vfsmount_node->next, |
284 | &fsnotify_mark_srcu); | |
7131485a | 285 | } |
ff8bcbd0 EP |
286 | ret = 0; |
287 | out: | |
75c1be48 | 288 | srcu_read_unlock(&fsnotify_mark_srcu, idx); |
90586523 EP |
289 | /* |
290 | * fsnotify_create_event() took a reference so the event can't be cleaned | |
291 | * up while we are still trying to add it to lists, drop that one. | |
292 | */ | |
293 | if (event) | |
294 | fsnotify_put_event(event); | |
c4ec54b4 | 295 | |
98b5c10d | 296 | return ret; |
90586523 EP |
297 | } |
298 | EXPORT_SYMBOL_GPL(fsnotify); | |
299 | ||
300 | static __init int fsnotify_init(void) | |
301 | { | |
75c1be48 EP |
302 | int ret; |
303 | ||
20dee624 EP |
304 | BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23); |
305 | ||
75c1be48 EP |
306 | ret = init_srcu_struct(&fsnotify_mark_srcu); |
307 | if (ret) | |
308 | panic("initializing fsnotify_mark_srcu"); | |
309 | ||
310 | return 0; | |
90586523 | 311 | } |
75c1be48 | 312 | core_initcall(fsnotify_init); |