Commit | Line | Data |
---|---|---|
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 | /* |
841bdc10 | 144 | * Attach an initialized mark mark to a given group and inode. |
3be25f49 EP |
145 | * These marks may be used for the fsnotify backend to determine which |
146 | * event types should be delivered to which group and for which inodes. | |
147 | */ | |
5444e298 EP |
148 | int fsnotify_add_inode_mark(struct fsnotify_mark *mark, |
149 | struct fsnotify_group *group, struct inode *inode, | |
150 | int allow_dups) | |
3be25f49 | 151 | { |
841bdc10 | 152 | struct fsnotify_mark *lmark = NULL; |
3be25f49 EP |
153 | int ret = 0; |
154 | ||
1ef5f13c EP |
155 | inode = igrab(inode); |
156 | if (unlikely(!inode)) | |
157 | return -EINVAL; | |
158 | ||
841bdc10 | 159 | mark->flags = FSNOTIFY_MARK_FLAG_INODE; |
098cf2fc | 160 | |
5444e298 EP |
161 | assert_spin_locked(&mark->lock); |
162 | assert_spin_locked(&group->mark_lock); | |
4ca76352 | 163 | |
3be25f49 EP |
164 | spin_lock(&inode->i_lock); |
165 | ||
40554c3d | 166 | if (!allow_dups) |
5444e298 | 167 | lmark = fsnotify_find_inode_mark_locked(group, inode); |
841bdc10 | 168 | if (!lmark) { |
841bdc10 | 169 | mark->i.inode = inode; |
9f0d793b | 170 | |
841bdc10 | 171 | hlist_add_head(&mark->i.i_list, &inode->i_fsnotify_marks); |
3be25f49 EP |
172 | |
173 | fsnotify_recalc_inode_mask_locked(inode); | |
174 | } | |
175 | ||
176 | spin_unlock(&inode->i_lock); | |
3be25f49 | 177 | |
841bdc10 | 178 | if (lmark) { |
3be25f49 | 179 | ret = -EEXIST; |
1ef5f13c | 180 | iput(inode); |
3be25f49 EP |
181 | } |
182 | ||
183 | return ret; | |
184 | } | |
164bc619 EP |
185 | |
186 | /** | |
187 | * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
188 | * @list: list of inodes being unmounted (sb->s_inodes) | |
189 | * | |
190 | * Called with inode_lock held, protecting the unmounting super block's list | |
191 | * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. | |
192 | * We temporarily drop inode_lock, however, and CAN block. | |
193 | */ | |
194 | void fsnotify_unmount_inodes(struct list_head *list) | |
195 | { | |
196 | struct inode *inode, *next_i, *need_iput = NULL; | |
197 | ||
198 | list_for_each_entry_safe(inode, next_i, list, i_sb_list) { | |
199 | struct inode *need_iput_tmp; | |
200 | ||
201 | /* | |
202 | * We cannot __iget() an inode in state I_CLEAR, I_FREEING, | |
203 | * I_WILL_FREE, or I_NEW which is fine because by that point | |
204 | * the inode cannot have any associated watches. | |
205 | */ | |
206 | if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW)) | |
207 | continue; | |
208 | ||
209 | /* | |
210 | * If i_count is zero, the inode cannot have any watches and | |
211 | * doing an __iget/iput with MS_ACTIVE clear would actually | |
212 | * evict all inodes with zero i_count from icache which is | |
213 | * unnecessarily violent and may in fact be illegal to do. | |
214 | */ | |
215 | if (!atomic_read(&inode->i_count)) | |
216 | continue; | |
217 | ||
218 | need_iput_tmp = need_iput; | |
219 | need_iput = NULL; | |
220 | ||
221 | /* In case fsnotify_inode_delete() drops a reference. */ | |
222 | if (inode != need_iput_tmp) | |
223 | __iget(inode); | |
224 | else | |
225 | need_iput_tmp = NULL; | |
226 | ||
227 | /* In case the dropping of a reference would nuke next_i. */ | |
228 | if ((&next_i->i_sb_list != list) && | |
229 | atomic_read(&next_i->i_count) && | |
230 | !(next_i->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))) { | |
231 | __iget(next_i); | |
232 | need_iput = next_i; | |
233 | } | |
234 | ||
235 | /* | |
236 | * We can safely drop inode_lock here because we hold | |
237 | * references on both inode and next_i. Also no new inodes | |
238 | * will be added since the umount has begun. Finally, | |
239 | * iprune_mutex keeps shrink_icache_memory() away. | |
240 | */ | |
241 | spin_unlock(&inode_lock); | |
242 | ||
243 | if (need_iput_tmp) | |
244 | iput(need_iput_tmp); | |
245 | ||
246 | /* for each watch, send FS_UNMOUNT and then remove it */ | |
247 | fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); | |
248 | ||
249 | fsnotify_inode_delete(inode); | |
250 | ||
251 | iput(inode); | |
252 | ||
253 | spin_lock(&inode_lock); | |
254 | } | |
255 | } |