Commit | Line | Data |
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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 | __u32 new_mask = 0; |
40 | ||
41 | assert_spin_locked(&inode->i_lock); | |
42 | ||
b67bfe0d | 43 | hlist_for_each_entry(mark, &inode->i_fsnotify_marks, i.i_list) |
841bdc10 | 44 | new_mask |= mark->mask; |
3be25f49 EP |
45 | inode->i_fsnotify_mask = new_mask; |
46 | } | |
47 | ||
48 | /* | |
49 | * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types | |
50 | * any notifier is interested in hearing for this inode. | |
51 | */ | |
52 | void fsnotify_recalc_inode_mask(struct inode *inode) | |
53 | { | |
54 | spin_lock(&inode->i_lock); | |
55 | fsnotify_recalc_inode_mask_locked(inode); | |
56 | spin_unlock(&inode->i_lock); | |
c28f7e56 EP |
57 | |
58 | __fsnotify_update_child_dentry_flags(inode); | |
3be25f49 EP |
59 | } |
60 | ||
5444e298 | 61 | void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) |
3be25f49 | 62 | { |
5444e298 | 63 | struct inode *inode = mark->i.inode; |
3be25f49 | 64 | |
986ab098 | 65 | BUG_ON(!mutex_is_locked(&mark->group->mark_mutex)); |
5444e298 | 66 | assert_spin_locked(&mark->lock); |
3be25f49 | 67 | |
3be25f49 EP |
68 | spin_lock(&inode->i_lock); |
69 | ||
a4c6e996 | 70 | hlist_del_init_rcu(&mark->i.i_list); |
841bdc10 | 71 | mark->i.inode = NULL; |
3be25f49 EP |
72 | |
73 | /* | |
e61ce867 | 74 | * this mark is now off the inode->i_fsnotify_marks list and we |
3be25f49 EP |
75 | * hold the inode->i_lock, so this is the perfect time to update the |
76 | * inode->i_fsnotify_mask | |
77 | */ | |
78 | fsnotify_recalc_inode_mask_locked(inode); | |
79 | ||
80 | spin_unlock(&inode->i_lock); | |
3be25f49 EP |
81 | } |
82 | ||
83 | /* | |
84 | * Given an inode, destroy all of the marks associated with that inode. | |
85 | */ | |
86 | void fsnotify_clear_marks_by_inode(struct inode *inode) | |
87 | { | |
841bdc10 | 88 | struct fsnotify_mark *mark, *lmark; |
b67bfe0d | 89 | struct hlist_node *n; |
3be25f49 EP |
90 | LIST_HEAD(free_list); |
91 | ||
92 | spin_lock(&inode->i_lock); | |
b67bfe0d | 93 | hlist_for_each_entry_safe(mark, n, &inode->i_fsnotify_marks, i.i_list) { |
841bdc10 | 94 | list_add(&mark->i.free_i_list, &free_list); |
a4c6e996 | 95 | hlist_del_init_rcu(&mark->i.i_list); |
841bdc10 | 96 | fsnotify_get_mark(mark); |
3be25f49 EP |
97 | } |
98 | spin_unlock(&inode->i_lock); | |
99 | ||
841bdc10 | 100 | list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) { |
e2a29943 LS |
101 | struct fsnotify_group *group; |
102 | ||
103 | spin_lock(&mark->lock); | |
104 | fsnotify_get_group(mark->group); | |
105 | group = mark->group; | |
106 | spin_unlock(&mark->lock); | |
107 | ||
108 | fsnotify_destroy_mark(mark, group); | |
841bdc10 | 109 | fsnotify_put_mark(mark); |
e2a29943 | 110 | fsnotify_put_group(group); |
3be25f49 EP |
111 | } |
112 | } | |
113 | ||
4d92604c EP |
114 | /* |
115 | * Given a group clear all of the inode marks associated with that group. | |
116 | */ | |
117 | void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) | |
118 | { | |
119 | fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE); | |
120 | } | |
121 | ||
3be25f49 EP |
122 | /* |
123 | * given a group and inode, find the mark associated with that combination. | |
124 | * if found take a reference to that mark and return it, else return NULL | |
125 | */ | |
ac5f121b TB |
126 | static struct fsnotify_mark *fsnotify_find_inode_mark_locked( |
127 | struct fsnotify_group *group, | |
128 | struct inode *inode) | |
3be25f49 | 129 | { |
841bdc10 | 130 | struct fsnotify_mark *mark; |
3be25f49 EP |
131 | |
132 | assert_spin_locked(&inode->i_lock); | |
133 | ||
b67bfe0d | 134 | hlist_for_each_entry(mark, &inode->i_fsnotify_marks, i.i_list) { |
841bdc10 EP |
135 | if (mark->group == group) { |
136 | fsnotify_get_mark(mark); | |
137 | return mark; | |
3be25f49 EP |
138 | } |
139 | } | |
140 | return NULL; | |
141 | } | |
142 | ||
143 | /* | |
35566087 AG |
144 | * given a group and inode, find the mark associated with that combination. |
145 | * if found take a reference to that mark and return it, else return NULL | |
3be25f49 | 146 | */ |
5444e298 EP |
147 | struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, |
148 | struct inode *inode) | |
35566087 AG |
149 | { |
150 | struct fsnotify_mark *mark; | |
151 | ||
152 | spin_lock(&inode->i_lock); | |
5444e298 | 153 | mark = fsnotify_find_inode_mark_locked(group, inode); |
35566087 AG |
154 | spin_unlock(&inode->i_lock); |
155 | ||
156 | return mark; | |
157 | } | |
3be25f49 | 158 | |
3be25f49 | 159 | /* |
90b1e7a5 EP |
160 | * If we are setting a mark mask on an inode mark we should pin the inode |
161 | * in memory. | |
162 | */ | |
163 | void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, | |
164 | __u32 mask) | |
3be25f49 | 165 | { |
90b1e7a5 EP |
166 | struct inode *inode; |
167 | ||
168 | assert_spin_locked(&mark->lock); | |
169 | ||
170 | if (mask && | |
171 | mark->i.inode && | |
172 | !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { | |
173 | mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; | |
174 | inode = igrab(mark->i.inode); | |
175 | /* | |
176 | * we shouldn't be able to get here if the inode wasn't | |
177 | * already safely held in memory. But bug in case it | |
178 | * ever is wrong. | |
179 | */ | |
180 | BUG_ON(!inode); | |
181 | } | |
3be25f49 EP |
182 | } |
183 | ||
184 | /* | |
0c6532e4 | 185 | * Attach an initialized mark to a given inode. |
3be25f49 | 186 | * These marks may be used for the fsnotify backend to determine which |
0c6532e4 | 187 | * event types should be delivered to which group and for which inodes. These |
6ad2d4e3 EP |
188 | * marks are ordered according to priority, highest number first, and then by |
189 | * the group's location in memory. | |
3be25f49 | 190 | */ |
5444e298 EP |
191 | int fsnotify_add_inode_mark(struct fsnotify_mark *mark, |
192 | struct fsnotify_group *group, struct inode *inode, | |
193 | int allow_dups) | |
3be25f49 | 194 | { |
b67bfe0d | 195 | struct fsnotify_mark *lmark, *last = NULL; |
3be25f49 EP |
196 | int ret = 0; |
197 | ||
700307a2 | 198 | mark->flags |= FSNOTIFY_MARK_FLAG_INODE; |
098cf2fc | 199 | |
986ab098 | 200 | BUG_ON(!mutex_is_locked(&group->mark_mutex)); |
5444e298 | 201 | assert_spin_locked(&mark->lock); |
1ef5f13c | 202 | |
3be25f49 EP |
203 | spin_lock(&inode->i_lock); |
204 | ||
0c6532e4 | 205 | mark->i.inode = inode; |
9f0d793b | 206 | |
0c6532e4 EP |
207 | /* is mark the first mark? */ |
208 | if (hlist_empty(&inode->i_fsnotify_marks)) { | |
a4c6e996 | 209 | hlist_add_head_rcu(&mark->i.i_list, &inode->i_fsnotify_marks); |
0c6532e4 EP |
210 | goto out; |
211 | } | |
3be25f49 | 212 | |
0c6532e4 | 213 | /* should mark be in the middle of the current list? */ |
b67bfe0d SL |
214 | hlist_for_each_entry(lmark, &inode->i_fsnotify_marks, i.i_list) { |
215 | last = lmark; | |
3be25f49 | 216 | |
0c6532e4 EP |
217 | if ((lmark->group == group) && !allow_dups) { |
218 | ret = -EEXIST; | |
219 | goto out; | |
220 | } | |
3be25f49 | 221 | |
6ad2d4e3 EP |
222 | if (mark->group->priority < lmark->group->priority) |
223 | continue; | |
224 | ||
225 | if ((mark->group->priority == lmark->group->priority) && | |
226 | (mark->group < lmark->group)) | |
0c6532e4 | 227 | continue; |
3be25f49 | 228 | |
a4c6e996 | 229 | hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list); |
0c6532e4 | 230 | goto out; |
3be25f49 EP |
231 | } |
232 | ||
0c6532e4 EP |
233 | BUG_ON(last == NULL); |
234 | /* mark should be the last entry. last is the current last entry */ | |
1d023284 | 235 | hlist_add_behind_rcu(&mark->i.i_list, &last->i.i_list); |
0c6532e4 EP |
236 | out: |
237 | fsnotify_recalc_inode_mask_locked(inode); | |
3be25f49 | 238 | spin_unlock(&inode->i_lock); |
3be25f49 EP |
239 | |
240 | return ret; | |
241 | } | |
164bc619 EP |
242 | |
243 | /** | |
244 | * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
245 | * @list: list of inodes being unmounted (sb->s_inodes) | |
246 | * | |
55fa6091 DC |
247 | * Called during unmount with no locks held, so needs to be safe against |
248 | * concurrent modifiers. We temporarily drop inode_sb_list_lock and CAN block. | |
164bc619 EP |
249 | */ |
250 | void fsnotify_unmount_inodes(struct list_head *list) | |
251 | { | |
252 | struct inode *inode, *next_i, *need_iput = NULL; | |
253 | ||
55fa6091 | 254 | spin_lock(&inode_sb_list_lock); |
164bc619 EP |
255 | list_for_each_entry_safe(inode, next_i, list, i_sb_list) { |
256 | struct inode *need_iput_tmp; | |
257 | ||
258 | /* | |
a4ffdde6 | 259 | * We cannot __iget() an inode in state I_FREEING, |
164bc619 EP |
260 | * I_WILL_FREE, or I_NEW which is fine because by that point |
261 | * the inode cannot have any associated watches. | |
262 | */ | |
250df6ed DC |
263 | spin_lock(&inode->i_lock); |
264 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { | |
265 | spin_unlock(&inode->i_lock); | |
164bc619 | 266 | continue; |
250df6ed | 267 | } |
164bc619 EP |
268 | |
269 | /* | |
270 | * If i_count is zero, the inode cannot have any watches and | |
271 | * doing an __iget/iput with MS_ACTIVE clear would actually | |
272 | * evict all inodes with zero i_count from icache which is | |
273 | * unnecessarily violent and may in fact be illegal to do. | |
274 | */ | |
250df6ed DC |
275 | if (!atomic_read(&inode->i_count)) { |
276 | spin_unlock(&inode->i_lock); | |
164bc619 | 277 | continue; |
250df6ed | 278 | } |
164bc619 EP |
279 | |
280 | need_iput_tmp = need_iput; | |
281 | need_iput = NULL; | |
282 | ||
283 | /* In case fsnotify_inode_delete() drops a reference. */ | |
284 | if (inode != need_iput_tmp) | |
285 | __iget(inode); | |
286 | else | |
287 | need_iput_tmp = NULL; | |
250df6ed | 288 | spin_unlock(&inode->i_lock); |
164bc619 EP |
289 | |
290 | /* In case the dropping of a reference would nuke next_i. */ | |
6424babf | 291 | while (&next_i->i_sb_list != list) { |
250df6ed | 292 | spin_lock(&next_i->i_lock); |
6424babf JH |
293 | if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) && |
294 | atomic_read(&next_i->i_count)) { | |
250df6ed DC |
295 | __iget(next_i); |
296 | need_iput = next_i; | |
6424babf JH |
297 | spin_unlock(&next_i->i_lock); |
298 | break; | |
250df6ed DC |
299 | } |
300 | spin_unlock(&next_i->i_lock); | |
6424babf JH |
301 | next_i = list_entry(next_i->i_sb_list.next, |
302 | struct inode, i_sb_list); | |
164bc619 EP |
303 | } |
304 | ||
305 | /* | |
6424babf JH |
306 | * We can safely drop inode_sb_list_lock here because either |
307 | * we actually hold references on both inode and next_i or | |
308 | * end of list. Also no new inodes will be added since the | |
309 | * umount has begun. | |
164bc619 | 310 | */ |
55fa6091 | 311 | spin_unlock(&inode_sb_list_lock); |
164bc619 EP |
312 | |
313 | if (need_iput_tmp) | |
314 | iput(need_iput_tmp); | |
315 | ||
316 | /* for each watch, send FS_UNMOUNT and then remove it */ | |
317 | fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); | |
318 | ||
319 | fsnotify_inode_delete(inode); | |
320 | ||
321 | iput(inode); | |
322 | ||
55fa6091 | 323 | spin_lock(&inode_sb_list_lock); |
164bc619 | 324 | } |
55fa6091 | 325 | spin_unlock(&inode_sb_list_lock); |
164bc619 | 326 | } |