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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 | ||
841bdc10 EP |
70 | hlist_del_init(&mark->i.i_list); |
71 | mark->i.inode = NULL; | |
3be25f49 | 72 | |
3be25f49 | 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); | |
95 | hlist_del_init(&mark->i.i_list); | |
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 | ||
5444e298 EP |
106 | /* |
107 | * given a group and inode, find the mark associated with that combination. | |
108 | * if found take a reference to that mark and return it, else return NULL | |
109 | */ | |
110 | struct fsnotify_mark *fsnotify_find_inode_mark_locked(struct fsnotify_group *group, | |
111 | struct inode *inode) | |
3be25f49 | 112 | { |
841bdc10 | 113 | struct fsnotify_mark *mark; |
3be25f49 EP |
114 | struct hlist_node *pos; |
115 | ||
116 | assert_spin_locked(&inode->i_lock); | |
117 | ||
841bdc10 EP |
118 | hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) { |
119 | if (mark->group == group) { | |
120 | fsnotify_get_mark(mark); | |
121 | return mark; | |
3be25f49 EP |
122 | } |
123 | } | |
124 | return NULL; | |
125 | } | |
126 | ||
35566087 AG |
127 | /* |
128 | * given a group and inode, find the mark associated with that combination. | |
129 | * if found take a reference to that mark and return it, else return NULL | |
130 | */ | |
5444e298 EP |
131 | struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, |
132 | struct inode *inode) | |
35566087 AG |
133 | { |
134 | struct fsnotify_mark *mark; | |
135 | ||
136 | spin_lock(&inode->i_lock); | |
5444e298 | 137 | mark = fsnotify_find_inode_mark_locked(group, inode); |
35566087 AG |
138 | spin_unlock(&inode->i_lock); |
139 | ||
140 | return mark; | |
141 | } | |
142 | ||
3be25f49 | 143 | /* |
90b1e7a5 EP |
144 | * If we are setting a mark mask on an inode mark we should pin the inode |
145 | * in memory. | |
146 | */ | |
147 | void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, | |
148 | __u32 mask) | |
149 | { | |
150 | struct inode *inode; | |
151 | ||
152 | assert_spin_locked(&mark->lock); | |
153 | ||
154 | if (mask && | |
155 | mark->i.inode && | |
156 | !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { | |
157 | mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; | |
158 | inode = igrab(mark->i.inode); | |
159 | /* | |
160 | * we shouldn't be able to get here if the inode wasn't | |
161 | * already safely held in memory. But bug in case it | |
162 | * ever is wrong. | |
163 | */ | |
164 | BUG_ON(!inode); | |
165 | } | |
166 | } | |
167 | ||
168 | /* | |
169 | * Attach an initialized mark to a given group and inode. | |
3be25f49 EP |
170 | * These marks may be used for the fsnotify backend to determine which |
171 | * event types should be delivered to which group and for which inodes. | |
172 | */ | |
5444e298 EP |
173 | int fsnotify_add_inode_mark(struct fsnotify_mark *mark, |
174 | struct fsnotify_group *group, struct inode *inode, | |
175 | int allow_dups) | |
3be25f49 | 176 | { |
841bdc10 | 177 | struct fsnotify_mark *lmark = NULL; |
3be25f49 EP |
178 | int ret = 0; |
179 | ||
841bdc10 | 180 | mark->flags = FSNOTIFY_MARK_FLAG_INODE; |
098cf2fc | 181 | |
5444e298 EP |
182 | assert_spin_locked(&mark->lock); |
183 | assert_spin_locked(&group->mark_lock); | |
4ca76352 | 184 | |
3be25f49 EP |
185 | spin_lock(&inode->i_lock); |
186 | ||
40554c3d | 187 | if (!allow_dups) |
5444e298 | 188 | lmark = fsnotify_find_inode_mark_locked(group, inode); |
841bdc10 | 189 | if (!lmark) { |
841bdc10 | 190 | mark->i.inode = inode; |
9f0d793b | 191 | |
841bdc10 | 192 | hlist_add_head(&mark->i.i_list, &inode->i_fsnotify_marks); |
3be25f49 EP |
193 | |
194 | fsnotify_recalc_inode_mask_locked(inode); | |
195 | } | |
196 | ||
197 | spin_unlock(&inode->i_lock); | |
3be25f49 | 198 | |
90b1e7a5 | 199 | if (lmark) |
3be25f49 | 200 | ret = -EEXIST; |
3be25f49 EP |
201 | |
202 | return ret; | |
203 | } | |
164bc619 EP |
204 | |
205 | /** | |
206 | * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
207 | * @list: list of inodes being unmounted (sb->s_inodes) | |
208 | * | |
209 | * Called with inode_lock held, protecting the unmounting super block's list | |
210 | * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. | |
211 | * We temporarily drop inode_lock, however, and CAN block. | |
212 | */ | |
213 | void fsnotify_unmount_inodes(struct list_head *list) | |
214 | { | |
215 | struct inode *inode, *next_i, *need_iput = NULL; | |
216 | ||
217 | list_for_each_entry_safe(inode, next_i, list, i_sb_list) { | |
218 | struct inode *need_iput_tmp; | |
219 | ||
220 | /* | |
221 | * We cannot __iget() an inode in state I_CLEAR, I_FREEING, | |
222 | * I_WILL_FREE, or I_NEW which is fine because by that point | |
223 | * the inode cannot have any associated watches. | |
224 | */ | |
225 | if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW)) | |
226 | continue; | |
227 | ||
228 | /* | |
229 | * If i_count is zero, the inode cannot have any watches and | |
230 | * doing an __iget/iput with MS_ACTIVE clear would actually | |
231 | * evict all inodes with zero i_count from icache which is | |
232 | * unnecessarily violent and may in fact be illegal to do. | |
233 | */ | |
234 | if (!atomic_read(&inode->i_count)) | |
235 | continue; | |
236 | ||
237 | need_iput_tmp = need_iput; | |
238 | need_iput = NULL; | |
239 | ||
240 | /* In case fsnotify_inode_delete() drops a reference. */ | |
241 | if (inode != need_iput_tmp) | |
242 | __iget(inode); | |
243 | else | |
244 | need_iput_tmp = NULL; | |
245 | ||
246 | /* In case the dropping of a reference would nuke next_i. */ | |
247 | if ((&next_i->i_sb_list != list) && | |
248 | atomic_read(&next_i->i_count) && | |
249 | !(next_i->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))) { | |
250 | __iget(next_i); | |
251 | need_iput = next_i; | |
252 | } | |
253 | ||
254 | /* | |
255 | * We can safely drop inode_lock here because we hold | |
256 | * references on both inode and next_i. Also no new inodes | |
257 | * will be added since the umount has begun. Finally, | |
258 | * iprune_mutex keeps shrink_icache_memory() away. | |
259 | */ | |
260 | spin_unlock(&inode_lock); | |
261 | ||
262 | if (need_iput_tmp) | |
263 | iput(need_iput_tmp); | |
264 | ||
265 | /* for each watch, send FS_UNMOUNT and then remove it */ | |
266 | fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); | |
267 | ||
268 | fsnotify_inode_delete(inode); | |
269 | ||
270 | iput(inode); | |
271 | ||
272 | spin_lock(&inode_lock); | |
273 | } | |
274 | } |