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3be25f49 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 | ||
3be25f49 EP |
19 | #include <linux/fs.h> |
20 | #include <linux/init.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/mutex.h> | |
3be25f49 EP |
24 | #include <linux/spinlock.h> |
25 | ||
60063497 | 26 | #include <linux/atomic.h> |
3be25f49 EP |
27 | |
28 | #include <linux/fsnotify_backend.h> | |
29 | #include "fsnotify.h" | |
30 | ||
55fa6091 DC |
31 | #include "../internal.h" |
32 | ||
3be25f49 EP |
33 | /* |
34 | * Recalculate the mask of events relevant to a given inode locked. | |
35 | */ | |
36 | static void fsnotify_recalc_inode_mask_locked(struct inode *inode) | |
37 | { | |
841bdc10 | 38 | struct fsnotify_mark *mark; |
3be25f49 EP |
39 | struct hlist_node *pos; |
40 | __u32 new_mask = 0; | |
41 | ||
42 | assert_spin_locked(&inode->i_lock); | |
43 | ||
841bdc10 EP |
44 | hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) |
45 | new_mask |= mark->mask; | |
3be25f49 EP |
46 | inode->i_fsnotify_mask = new_mask; |
47 | } | |
48 | ||
49 | /* | |
50 | * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types | |
51 | * any notifier is interested in hearing for this inode. | |
52 | */ | |
53 | void fsnotify_recalc_inode_mask(struct inode *inode) | |
54 | { | |
55 | spin_lock(&inode->i_lock); | |
56 | fsnotify_recalc_inode_mask_locked(inode); | |
57 | spin_unlock(&inode->i_lock); | |
c28f7e56 EP |
58 | |
59 | __fsnotify_update_child_dentry_flags(inode); | |
3be25f49 EP |
60 | } |
61 | ||
5444e298 | 62 | void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) |
3be25f49 | 63 | { |
5444e298 | 64 | struct inode *inode = mark->i.inode; |
3be25f49 | 65 | |
5444e298 EP |
66 | assert_spin_locked(&mark->lock); |
67 | assert_spin_locked(&mark->group->mark_lock); | |
3be25f49 | 68 | |
3be25f49 EP |
69 | spin_lock(&inode->i_lock); |
70 | ||
a4c6e996 | 71 | hlist_del_init_rcu(&mark->i.i_list); |
841bdc10 | 72 | mark->i.inode = NULL; |
3be25f49 EP |
73 | |
74 | /* | |
e61ce867 | 75 | * this mark is now off the inode->i_fsnotify_marks list and we |
3be25f49 EP |
76 | * hold the inode->i_lock, so this is the perfect time to update the |
77 | * inode->i_fsnotify_mask | |
78 | */ | |
79 | fsnotify_recalc_inode_mask_locked(inode); | |
80 | ||
81 | spin_unlock(&inode->i_lock); | |
3be25f49 EP |
82 | } |
83 | ||
84 | /* | |
85 | * Given an inode, destroy all of the marks associated with that inode. | |
86 | */ | |
87 | void fsnotify_clear_marks_by_inode(struct inode *inode) | |
88 | { | |
841bdc10 | 89 | struct fsnotify_mark *mark, *lmark; |
3be25f49 EP |
90 | struct hlist_node *pos, *n; |
91 | LIST_HEAD(free_list); | |
92 | ||
93 | spin_lock(&inode->i_lock); | |
841bdc10 EP |
94 | hlist_for_each_entry_safe(mark, pos, n, &inode->i_fsnotify_marks, i.i_list) { |
95 | list_add(&mark->i.free_i_list, &free_list); | |
a4c6e996 | 96 | hlist_del_init_rcu(&mark->i.i_list); |
841bdc10 | 97 | fsnotify_get_mark(mark); |
3be25f49 EP |
98 | } |
99 | spin_unlock(&inode->i_lock); | |
100 | ||
841bdc10 EP |
101 | list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) { |
102 | fsnotify_destroy_mark(mark); | |
103 | fsnotify_put_mark(mark); | |
3be25f49 EP |
104 | } |
105 | } | |
106 | ||
4d92604c EP |
107 | /* |
108 | * Given a group clear all of the inode marks associated with that group. | |
109 | */ | |
110 | void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) | |
111 | { | |
112 | fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE); | |
113 | } | |
114 | ||
3be25f49 EP |
115 | /* |
116 | * given a group and inode, find the mark associated with that combination. | |
117 | * if found take a reference to that mark and return it, else return NULL | |
118 | */ | |
5444e298 EP |
119 | struct fsnotify_mark *fsnotify_find_inode_mark_locked(struct fsnotify_group *group, |
120 | struct inode *inode) | |
3be25f49 | 121 | { |
841bdc10 | 122 | struct fsnotify_mark *mark; |
3be25f49 EP |
123 | struct hlist_node *pos; |
124 | ||
125 | assert_spin_locked(&inode->i_lock); | |
126 | ||
841bdc10 EP |
127 | hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) { |
128 | if (mark->group == group) { | |
129 | fsnotify_get_mark(mark); | |
130 | return mark; | |
3be25f49 EP |
131 | } |
132 | } | |
133 | return NULL; | |
134 | } | |
135 | ||
136 | /* | |
35566087 AG |
137 | * given a group and inode, find the mark associated with that combination. |
138 | * if found take a reference to that mark and return it, else return NULL | |
3be25f49 | 139 | */ |
5444e298 EP |
140 | struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, |
141 | struct inode *inode) | |
35566087 AG |
142 | { |
143 | struct fsnotify_mark *mark; | |
144 | ||
145 | spin_lock(&inode->i_lock); | |
5444e298 | 146 | mark = fsnotify_find_inode_mark_locked(group, inode); |
35566087 AG |
147 | spin_unlock(&inode->i_lock); |
148 | ||
149 | return mark; | |
150 | } | |
3be25f49 | 151 | |
3be25f49 | 152 | /* |
90b1e7a5 EP |
153 | * If we are setting a mark mask on an inode mark we should pin the inode |
154 | * in memory. | |
155 | */ | |
156 | void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, | |
157 | __u32 mask) | |
3be25f49 | 158 | { |
90b1e7a5 EP |
159 | struct inode *inode; |
160 | ||
161 | assert_spin_locked(&mark->lock); | |
162 | ||
163 | if (mask && | |
164 | mark->i.inode && | |
165 | !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { | |
166 | mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; | |
167 | inode = igrab(mark->i.inode); | |
168 | /* | |
169 | * we shouldn't be able to get here if the inode wasn't | |
170 | * already safely held in memory. But bug in case it | |
171 | * ever is wrong. | |
172 | */ | |
173 | BUG_ON(!inode); | |
174 | } | |
3be25f49 EP |
175 | } |
176 | ||
177 | /* | |
0c6532e4 | 178 | * Attach an initialized mark to a given inode. |
3be25f49 | 179 | * These marks may be used for the fsnotify backend to determine which |
0c6532e4 | 180 | * event types should be delivered to which group and for which inodes. These |
6ad2d4e3 EP |
181 | * marks are ordered according to priority, highest number first, and then by |
182 | * the group's location in memory. | |
3be25f49 | 183 | */ |
5444e298 EP |
184 | int fsnotify_add_inode_mark(struct fsnotify_mark *mark, |
185 | struct fsnotify_group *group, struct inode *inode, | |
186 | int allow_dups) | |
3be25f49 | 187 | { |
0c6532e4 EP |
188 | struct fsnotify_mark *lmark; |
189 | struct hlist_node *node, *last = NULL; | |
3be25f49 EP |
190 | int ret = 0; |
191 | ||
700307a2 | 192 | mark->flags |= FSNOTIFY_MARK_FLAG_INODE; |
098cf2fc | 193 | |
5444e298 EP |
194 | assert_spin_locked(&mark->lock); |
195 | assert_spin_locked(&group->mark_lock); | |
1ef5f13c | 196 | |
3be25f49 EP |
197 | spin_lock(&inode->i_lock); |
198 | ||
0c6532e4 | 199 | mark->i.inode = inode; |
9f0d793b | 200 | |
0c6532e4 EP |
201 | /* is mark the first mark? */ |
202 | if (hlist_empty(&inode->i_fsnotify_marks)) { | |
a4c6e996 | 203 | hlist_add_head_rcu(&mark->i.i_list, &inode->i_fsnotify_marks); |
0c6532e4 EP |
204 | goto out; |
205 | } | |
3be25f49 | 206 | |
0c6532e4 EP |
207 | /* should mark be in the middle of the current list? */ |
208 | hlist_for_each_entry(lmark, node, &inode->i_fsnotify_marks, i.i_list) { | |
209 | last = node; | |
3be25f49 | 210 | |
0c6532e4 EP |
211 | if ((lmark->group == group) && !allow_dups) { |
212 | ret = -EEXIST; | |
213 | goto out; | |
214 | } | |
3be25f49 | 215 | |
6ad2d4e3 EP |
216 | if (mark->group->priority < lmark->group->priority) |
217 | continue; | |
218 | ||
219 | if ((mark->group->priority == lmark->group->priority) && | |
220 | (mark->group < lmark->group)) | |
0c6532e4 | 221 | continue; |
3be25f49 | 222 | |
a4c6e996 | 223 | hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list); |
0c6532e4 | 224 | goto out; |
3be25f49 EP |
225 | } |
226 | ||
0c6532e4 EP |
227 | BUG_ON(last == NULL); |
228 | /* mark should be the last entry. last is the current last entry */ | |
a4c6e996 | 229 | hlist_add_after_rcu(last, &mark->i.i_list); |
0c6532e4 EP |
230 | out: |
231 | fsnotify_recalc_inode_mask_locked(inode); | |
3be25f49 | 232 | spin_unlock(&inode->i_lock); |
3be25f49 EP |
233 | |
234 | return ret; | |
235 | } | |
164bc619 EP |
236 | |
237 | /** | |
238 | * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
239 | * @list: list of inodes being unmounted (sb->s_inodes) | |
240 | * | |
55fa6091 DC |
241 | * Called during unmount with no locks held, so needs to be safe against |
242 | * concurrent modifiers. We temporarily drop inode_sb_list_lock and CAN block. | |
164bc619 EP |
243 | */ |
244 | void fsnotify_unmount_inodes(struct list_head *list) | |
245 | { | |
246 | struct inode *inode, *next_i, *need_iput = NULL; | |
247 | ||
55fa6091 | 248 | spin_lock(&inode_sb_list_lock); |
164bc619 EP |
249 | list_for_each_entry_safe(inode, next_i, list, i_sb_list) { |
250 | struct inode *need_iput_tmp; | |
251 | ||
252 | /* | |
a4ffdde6 | 253 | * We cannot __iget() an inode in state I_FREEING, |
164bc619 EP |
254 | * I_WILL_FREE, or I_NEW which is fine because by that point |
255 | * the inode cannot have any associated watches. | |
256 | */ | |
250df6ed DC |
257 | spin_lock(&inode->i_lock); |
258 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { | |
259 | spin_unlock(&inode->i_lock); | |
164bc619 | 260 | continue; |
250df6ed | 261 | } |
164bc619 EP |
262 | |
263 | /* | |
264 | * If i_count is zero, the inode cannot have any watches and | |
265 | * doing an __iget/iput with MS_ACTIVE clear would actually | |
266 | * evict all inodes with zero i_count from icache which is | |
267 | * unnecessarily violent and may in fact be illegal to do. | |
268 | */ | |
250df6ed DC |
269 | if (!atomic_read(&inode->i_count)) { |
270 | spin_unlock(&inode->i_lock); | |
164bc619 | 271 | continue; |
250df6ed | 272 | } |
164bc619 EP |
273 | |
274 | need_iput_tmp = need_iput; | |
275 | need_iput = NULL; | |
276 | ||
277 | /* In case fsnotify_inode_delete() drops a reference. */ | |
278 | if (inode != need_iput_tmp) | |
279 | __iget(inode); | |
280 | else | |
281 | need_iput_tmp = NULL; | |
250df6ed | 282 | spin_unlock(&inode->i_lock); |
164bc619 EP |
283 | |
284 | /* In case the dropping of a reference would nuke next_i. */ | |
285 | if ((&next_i->i_sb_list != list) && | |
250df6ed DC |
286 | atomic_read(&next_i->i_count)) { |
287 | spin_lock(&next_i->i_lock); | |
288 | if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) { | |
289 | __iget(next_i); | |
290 | need_iput = next_i; | |
291 | } | |
292 | spin_unlock(&next_i->i_lock); | |
164bc619 EP |
293 | } |
294 | ||
295 | /* | |
55fa6091 | 296 | * We can safely drop inode_sb_list_lock here because we hold |
164bc619 | 297 | * references on both inode and next_i. Also no new inodes |
55fa6091 | 298 | * will be added since the umount has begun. |
164bc619 | 299 | */ |
55fa6091 | 300 | spin_unlock(&inode_sb_list_lock); |
164bc619 EP |
301 | |
302 | if (need_iput_tmp) | |
303 | iput(need_iput_tmp); | |
304 | ||
305 | /* for each watch, send FS_UNMOUNT and then remove it */ | |
306 | fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); | |
307 | ||
308 | fsnotify_inode_delete(inode); | |
309 | ||
310 | iput(inode); | |
311 | ||
55fa6091 | 312 | spin_lock(&inode_sb_list_lock); |
164bc619 | 313 | } |
55fa6091 | 314 | spin_unlock(&inode_sb_list_lock); |
164bc619 | 315 | } |