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 | 24 | #include <linux/spinlock.h> |
164bc619 | 25 | #include <linux/writeback.h> /* for inode_lock */ |
3be25f49 EP |
26 | |
27 | #include <asm/atomic.h> | |
28 | ||
29 | #include <linux/fsnotify_backend.h> | |
30 | #include "fsnotify.h" | |
31 | ||
3be25f49 EP |
32 | /* |
33 | * Recalculate the mask of events relevant to a given inode locked. | |
34 | */ | |
35 | static void fsnotify_recalc_inode_mask_locked(struct inode *inode) | |
36 | { | |
841bdc10 | 37 | struct fsnotify_mark *mark; |
3be25f49 EP |
38 | struct hlist_node *pos; |
39 | __u32 new_mask = 0; | |
40 | ||
41 | assert_spin_locked(&inode->i_lock); | |
42 | ||
841bdc10 EP |
43 | hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) |
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 | |
5444e298 EP |
65 | assert_spin_locked(&mark->lock); |
66 | assert_spin_locked(&mark->group->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; |
3be25f49 EP |
89 | struct hlist_node *pos, *n; |
90 | LIST_HEAD(free_list); | |
91 | ||
92 | spin_lock(&inode->i_lock); | |
841bdc10 EP |
93 | hlist_for_each_entry_safe(mark, pos, n, &inode->i_fsnotify_marks, i.i_list) { |
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 EP |
100 | list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) { |
101 | fsnotify_destroy_mark(mark); | |
102 | fsnotify_put_mark(mark); | |
3be25f49 EP |
103 | } |
104 | } | |
105 | ||
4d92604c EP |
106 | /* |
107 | * Given a group clear all of the inode marks associated with that group. | |
108 | */ | |
109 | void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) | |
110 | { | |
111 | fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE); | |
112 | } | |
113 | ||
3be25f49 EP |
114 | /* |
115 | * given a group and inode, find the mark associated with that combination. | |
116 | * if found take a reference to that mark and return it, else return NULL | |
117 | */ | |
5444e298 EP |
118 | struct fsnotify_mark *fsnotify_find_inode_mark_locked(struct fsnotify_group *group, |
119 | struct inode *inode) | |
3be25f49 | 120 | { |
841bdc10 | 121 | struct fsnotify_mark *mark; |
3be25f49 EP |
122 | struct hlist_node *pos; |
123 | ||
124 | assert_spin_locked(&inode->i_lock); | |
125 | ||
841bdc10 EP |
126 | hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) { |
127 | if (mark->group == group) { | |
128 | fsnotify_get_mark(mark); | |
129 | return mark; | |
3be25f49 EP |
130 | } |
131 | } | |
132 | return NULL; | |
133 | } | |
134 | ||
135 | /* | |
35566087 AG |
136 | * given a group and inode, find the mark associated with that combination. |
137 | * if found take a reference to that mark and return it, else return NULL | |
3be25f49 | 138 | */ |
5444e298 EP |
139 | struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, |
140 | struct inode *inode) | |
35566087 AG |
141 | { |
142 | struct fsnotify_mark *mark; | |
143 | ||
144 | spin_lock(&inode->i_lock); | |
5444e298 | 145 | mark = fsnotify_find_inode_mark_locked(group, inode); |
35566087 AG |
146 | spin_unlock(&inode->i_lock); |
147 | ||
148 | return mark; | |
149 | } | |
3be25f49 | 150 | |
3be25f49 | 151 | /* |
90b1e7a5 EP |
152 | * If we are setting a mark mask on an inode mark we should pin the inode |
153 | * in memory. | |
154 | */ | |
155 | void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, | |
156 | __u32 mask) | |
3be25f49 | 157 | { |
90b1e7a5 EP |
158 | struct inode *inode; |
159 | ||
160 | assert_spin_locked(&mark->lock); | |
161 | ||
162 | if (mask && | |
163 | mark->i.inode && | |
164 | !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { | |
165 | mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; | |
166 | inode = igrab(mark->i.inode); | |
167 | /* | |
168 | * we shouldn't be able to get here if the inode wasn't | |
169 | * already safely held in memory. But bug in case it | |
170 | * ever is wrong. | |
171 | */ | |
172 | BUG_ON(!inode); | |
173 | } | |
3be25f49 EP |
174 | } |
175 | ||
176 | /* | |
0c6532e4 | 177 | * Attach an initialized mark to a given inode. |
3be25f49 | 178 | * These marks may be used for the fsnotify backend to determine which |
0c6532e4 EP |
179 | * event types should be delivered to which group and for which inodes. These |
180 | * marks are ordered according to the group's location in memory. | |
3be25f49 | 181 | */ |
5444e298 EP |
182 | int fsnotify_add_inode_mark(struct fsnotify_mark *mark, |
183 | struct fsnotify_group *group, struct inode *inode, | |
184 | int allow_dups) | |
3be25f49 | 185 | { |
0c6532e4 EP |
186 | struct fsnotify_mark *lmark; |
187 | struct hlist_node *node, *last = NULL; | |
3be25f49 EP |
188 | int ret = 0; |
189 | ||
700307a2 | 190 | mark->flags |= FSNOTIFY_MARK_FLAG_INODE; |
098cf2fc | 191 | |
5444e298 EP |
192 | assert_spin_locked(&mark->lock); |
193 | assert_spin_locked(&group->mark_lock); | |
1ef5f13c | 194 | |
3be25f49 EP |
195 | spin_lock(&inode->i_lock); |
196 | ||
0c6532e4 | 197 | mark->i.inode = inode; |
9f0d793b | 198 | |
0c6532e4 EP |
199 | /* is mark the first mark? */ |
200 | if (hlist_empty(&inode->i_fsnotify_marks)) { | |
a4c6e996 | 201 | hlist_add_head_rcu(&mark->i.i_list, &inode->i_fsnotify_marks); |
0c6532e4 EP |
202 | goto out; |
203 | } | |
3be25f49 | 204 | |
0c6532e4 EP |
205 | /* should mark be in the middle of the current list? */ |
206 | hlist_for_each_entry(lmark, node, &inode->i_fsnotify_marks, i.i_list) { | |
207 | last = node; | |
3be25f49 | 208 | |
0c6532e4 EP |
209 | if ((lmark->group == group) && !allow_dups) { |
210 | ret = -EEXIST; | |
211 | goto out; | |
212 | } | |
3be25f49 | 213 | |
0c6532e4 EP |
214 | if (mark->group < lmark->group) |
215 | continue; | |
3be25f49 | 216 | |
a4c6e996 | 217 | hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list); |
0c6532e4 | 218 | goto out; |
3be25f49 EP |
219 | } |
220 | ||
0c6532e4 EP |
221 | BUG_ON(last == NULL); |
222 | /* mark should be the last entry. last is the current last entry */ | |
a4c6e996 | 223 | hlist_add_after_rcu(last, &mark->i.i_list); |
0c6532e4 EP |
224 | out: |
225 | fsnotify_recalc_inode_mask_locked(inode); | |
3be25f49 | 226 | spin_unlock(&inode->i_lock); |
3be25f49 EP |
227 | |
228 | return ret; | |
229 | } | |
164bc619 EP |
230 | |
231 | /** | |
232 | * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
233 | * @list: list of inodes being unmounted (sb->s_inodes) | |
234 | * | |
235 | * Called with inode_lock held, protecting the unmounting super block's list | |
236 | * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. | |
237 | * We temporarily drop inode_lock, however, and CAN block. | |
238 | */ | |
239 | void fsnotify_unmount_inodes(struct list_head *list) | |
240 | { | |
241 | struct inode *inode, *next_i, *need_iput = NULL; | |
242 | ||
243 | list_for_each_entry_safe(inode, next_i, list, i_sb_list) { | |
244 | struct inode *need_iput_tmp; | |
245 | ||
246 | /* | |
a4ffdde6 | 247 | * We cannot __iget() an inode in state I_FREEING, |
164bc619 EP |
248 | * I_WILL_FREE, or I_NEW which is fine because by that point |
249 | * the inode cannot have any associated watches. | |
250 | */ | |
a4ffdde6 | 251 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) |
164bc619 EP |
252 | continue; |
253 | ||
254 | /* | |
255 | * If i_count is zero, the inode cannot have any watches and | |
256 | * doing an __iget/iput with MS_ACTIVE clear would actually | |
257 | * evict all inodes with zero i_count from icache which is | |
258 | * unnecessarily violent and may in fact be illegal to do. | |
259 | */ | |
260 | if (!atomic_read(&inode->i_count)) | |
261 | continue; | |
262 | ||
263 | need_iput_tmp = need_iput; | |
264 | need_iput = NULL; | |
265 | ||
266 | /* In case fsnotify_inode_delete() drops a reference. */ | |
267 | if (inode != need_iput_tmp) | |
268 | __iget(inode); | |
269 | else | |
270 | need_iput_tmp = NULL; | |
271 | ||
272 | /* In case the dropping of a reference would nuke next_i. */ | |
273 | if ((&next_i->i_sb_list != list) && | |
274 | atomic_read(&next_i->i_count) && | |
a4ffdde6 | 275 | !(next_i->i_state & (I_FREEING | I_WILL_FREE))) { |
164bc619 EP |
276 | __iget(next_i); |
277 | need_iput = next_i; | |
278 | } | |
279 | ||
280 | /* | |
281 | * We can safely drop inode_lock here because we hold | |
282 | * references on both inode and next_i. Also no new inodes | |
283 | * will be added since the umount has begun. Finally, | |
284 | * iprune_mutex keeps shrink_icache_memory() away. | |
285 | */ | |
286 | spin_unlock(&inode_lock); | |
287 | ||
288 | if (need_iput_tmp) | |
289 | iput(need_iput_tmp); | |
290 | ||
291 | /* for each watch, send FS_UNMOUNT and then remove it */ | |
292 | fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); | |
293 | ||
294 | fsnotify_inode_delete(inode); | |
295 | ||
296 | iput(inode); | |
297 | ||
298 | spin_lock(&inode_lock); | |
299 | } | |
300 | } |