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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 inode->i_fsnotify_mask, or the mask of all FS_* event types | |
35 | * any notifier is interested in hearing for this inode. | |
36 | */ | |
37 | void fsnotify_recalc_inode_mask(struct inode *inode) | |
38 | { | |
39 | spin_lock(&inode->i_lock); | |
0809ab69 | 40 | inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks); |
3be25f49 | 41 | spin_unlock(&inode->i_lock); |
c28f7e56 EP |
42 | |
43 | __fsnotify_update_child_dentry_flags(inode); | |
3be25f49 EP |
44 | } |
45 | ||
5444e298 | 46 | void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) |
3be25f49 | 47 | { |
0809ab69 | 48 | struct inode *inode = mark->inode; |
3be25f49 | 49 | |
986ab098 | 50 | BUG_ON(!mutex_is_locked(&mark->group->mark_mutex)); |
5444e298 | 51 | assert_spin_locked(&mark->lock); |
3be25f49 | 52 | |
3be25f49 EP |
53 | spin_lock(&inode->i_lock); |
54 | ||
0809ab69 JK |
55 | hlist_del_init_rcu(&mark->obj_list); |
56 | mark->inode = NULL; | |
3be25f49 EP |
57 | |
58 | /* | |
e61ce867 | 59 | * this mark is now off the inode->i_fsnotify_marks list and we |
3be25f49 EP |
60 | * hold the inode->i_lock, so this is the perfect time to update the |
61 | * inode->i_fsnotify_mask | |
62 | */ | |
0809ab69 | 63 | inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks); |
3be25f49 | 64 | spin_unlock(&inode->i_lock); |
3be25f49 EP |
65 | } |
66 | ||
67 | /* | |
68 | * Given an inode, destroy all of the marks associated with that inode. | |
69 | */ | |
70 | void fsnotify_clear_marks_by_inode(struct inode *inode) | |
71 | { | |
0809ab69 | 72 | struct fsnotify_mark *mark; |
b67bfe0d | 73 | struct hlist_node *n; |
3be25f49 EP |
74 | LIST_HEAD(free_list); |
75 | ||
76 | spin_lock(&inode->i_lock); | |
0809ab69 JK |
77 | hlist_for_each_entry_safe(mark, n, &inode->i_fsnotify_marks, obj_list) { |
78 | list_add(&mark->free_list, &free_list); | |
79 | hlist_del_init_rcu(&mark->obj_list); | |
841bdc10 | 80 | fsnotify_get_mark(mark); |
3be25f49 EP |
81 | } |
82 | spin_unlock(&inode->i_lock); | |
83 | ||
0809ab69 | 84 | fsnotify_destroy_marks(&free_list); |
3be25f49 EP |
85 | } |
86 | ||
4d92604c EP |
87 | /* |
88 | * Given a group clear all of the inode marks associated with that group. | |
89 | */ | |
90 | void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) | |
91 | { | |
92 | fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE); | |
93 | } | |
94 | ||
3be25f49 | 95 | /* |
35566087 AG |
96 | * given a group and inode, find the mark associated with that combination. |
97 | * if found take a reference to that mark and return it, else return NULL | |
3be25f49 | 98 | */ |
5444e298 EP |
99 | struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, |
100 | struct inode *inode) | |
35566087 AG |
101 | { |
102 | struct fsnotify_mark *mark; | |
103 | ||
104 | spin_lock(&inode->i_lock); | |
0809ab69 | 105 | mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group); |
35566087 AG |
106 | spin_unlock(&inode->i_lock); |
107 | ||
108 | return mark; | |
109 | } | |
3be25f49 | 110 | |
3be25f49 | 111 | /* |
90b1e7a5 EP |
112 | * If we are setting a mark mask on an inode mark we should pin the inode |
113 | * in memory. | |
114 | */ | |
115 | void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, | |
116 | __u32 mask) | |
3be25f49 | 117 | { |
90b1e7a5 EP |
118 | struct inode *inode; |
119 | ||
120 | assert_spin_locked(&mark->lock); | |
121 | ||
122 | if (mask && | |
0809ab69 | 123 | mark->inode && |
90b1e7a5 EP |
124 | !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { |
125 | mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; | |
0809ab69 | 126 | inode = igrab(mark->inode); |
90b1e7a5 EP |
127 | /* |
128 | * we shouldn't be able to get here if the inode wasn't | |
129 | * already safely held in memory. But bug in case it | |
130 | * ever is wrong. | |
131 | */ | |
132 | BUG_ON(!inode); | |
133 | } | |
3be25f49 EP |
134 | } |
135 | ||
136 | /* | |
0c6532e4 | 137 | * Attach an initialized mark to a given inode. |
3be25f49 | 138 | * These marks may be used for the fsnotify backend to determine which |
0c6532e4 | 139 | * event types should be delivered to which group and for which inodes. These |
6ad2d4e3 EP |
140 | * marks are ordered according to priority, highest number first, and then by |
141 | * the group's location in memory. | |
3be25f49 | 142 | */ |
5444e298 EP |
143 | int fsnotify_add_inode_mark(struct fsnotify_mark *mark, |
144 | struct fsnotify_group *group, struct inode *inode, | |
145 | int allow_dups) | |
3be25f49 | 146 | { |
0809ab69 | 147 | int ret; |
3be25f49 | 148 | |
700307a2 | 149 | mark->flags |= FSNOTIFY_MARK_FLAG_INODE; |
098cf2fc | 150 | |
986ab098 | 151 | BUG_ON(!mutex_is_locked(&group->mark_mutex)); |
5444e298 | 152 | assert_spin_locked(&mark->lock); |
1ef5f13c | 153 | |
3be25f49 | 154 | spin_lock(&inode->i_lock); |
0809ab69 JK |
155 | mark->inode = inode; |
156 | ret = fsnotify_add_mark_list(&inode->i_fsnotify_marks, mark, | |
157 | allow_dups); | |
158 | inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks); | |
3be25f49 | 159 | spin_unlock(&inode->i_lock); |
3be25f49 EP |
160 | |
161 | return ret; | |
162 | } | |
164bc619 EP |
163 | |
164 | /** | |
165 | * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. | |
166 | * @list: list of inodes being unmounted (sb->s_inodes) | |
167 | * | |
55fa6091 DC |
168 | * Called during unmount with no locks held, so needs to be safe against |
169 | * concurrent modifiers. We temporarily drop inode_sb_list_lock and CAN block. | |
164bc619 EP |
170 | */ |
171 | void fsnotify_unmount_inodes(struct list_head *list) | |
172 | { | |
173 | struct inode *inode, *next_i, *need_iput = NULL; | |
174 | ||
55fa6091 | 175 | spin_lock(&inode_sb_list_lock); |
164bc619 EP |
176 | list_for_each_entry_safe(inode, next_i, list, i_sb_list) { |
177 | struct inode *need_iput_tmp; | |
178 | ||
179 | /* | |
a4ffdde6 | 180 | * We cannot __iget() an inode in state I_FREEING, |
164bc619 EP |
181 | * I_WILL_FREE, or I_NEW which is fine because by that point |
182 | * the inode cannot have any associated watches. | |
183 | */ | |
250df6ed DC |
184 | spin_lock(&inode->i_lock); |
185 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { | |
186 | spin_unlock(&inode->i_lock); | |
164bc619 | 187 | continue; |
250df6ed | 188 | } |
164bc619 EP |
189 | |
190 | /* | |
191 | * If i_count is zero, the inode cannot have any watches and | |
192 | * doing an __iget/iput with MS_ACTIVE clear would actually | |
193 | * evict all inodes with zero i_count from icache which is | |
194 | * unnecessarily violent and may in fact be illegal to do. | |
195 | */ | |
250df6ed DC |
196 | if (!atomic_read(&inode->i_count)) { |
197 | spin_unlock(&inode->i_lock); | |
164bc619 | 198 | continue; |
250df6ed | 199 | } |
164bc619 EP |
200 | |
201 | need_iput_tmp = need_iput; | |
202 | need_iput = NULL; | |
203 | ||
204 | /* In case fsnotify_inode_delete() drops a reference. */ | |
205 | if (inode != need_iput_tmp) | |
206 | __iget(inode); | |
207 | else | |
208 | need_iput_tmp = NULL; | |
250df6ed | 209 | spin_unlock(&inode->i_lock); |
164bc619 EP |
210 | |
211 | /* In case the dropping of a reference would nuke next_i. */ | |
6424babf | 212 | while (&next_i->i_sb_list != list) { |
250df6ed | 213 | spin_lock(&next_i->i_lock); |
6424babf JH |
214 | if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) && |
215 | atomic_read(&next_i->i_count)) { | |
250df6ed DC |
216 | __iget(next_i); |
217 | need_iput = next_i; | |
6424babf JH |
218 | spin_unlock(&next_i->i_lock); |
219 | break; | |
250df6ed DC |
220 | } |
221 | spin_unlock(&next_i->i_lock); | |
6424babf JH |
222 | next_i = list_entry(next_i->i_sb_list.next, |
223 | struct inode, i_sb_list); | |
164bc619 EP |
224 | } |
225 | ||
226 | /* | |
6424babf JH |
227 | * We can safely drop inode_sb_list_lock here because either |
228 | * we actually hold references on both inode and next_i or | |
229 | * end of list. Also no new inodes will be added since the | |
230 | * umount has begun. | |
164bc619 | 231 | */ |
55fa6091 | 232 | spin_unlock(&inode_sb_list_lock); |
164bc619 EP |
233 | |
234 | if (need_iput_tmp) | |
235 | iput(need_iput_tmp); | |
236 | ||
237 | /* for each watch, send FS_UNMOUNT and then remove it */ | |
238 | fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); | |
239 | ||
240 | fsnotify_inode_delete(inode); | |
241 | ||
242 | iput(inode); | |
243 | ||
55fa6091 | 244 | spin_lock(&inode_sb_list_lock); |
164bc619 | 245 | } |
55fa6091 | 246 | spin_unlock(&inode_sb_list_lock); |
164bc619 | 247 | } |