2 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
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)
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.
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.
20 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/spinlock.h>
26 #include <linux/atomic.h>
28 #include <linux/fsnotify_backend.h>
31 #include "../internal.h"
34 * Recalculate the mask of events relevant to a given inode locked.
36 static void fsnotify_recalc_inode_mask_locked(struct inode
*inode
)
38 struct fsnotify_mark
*mark
;
39 struct hlist_node
*pos
;
42 assert_spin_locked(&inode
->i_lock
);
44 hlist_for_each_entry(mark
, pos
, &inode
->i_fsnotify_marks
, i
.i_list
)
45 new_mask
|= mark
->mask
;
46 inode
->i_fsnotify_mask
= new_mask
;
50 * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types
51 * any notifier is interested in hearing for this inode.
53 void fsnotify_recalc_inode_mask(struct inode
*inode
)
55 spin_lock(&inode
->i_lock
);
56 fsnotify_recalc_inode_mask_locked(inode
);
57 spin_unlock(&inode
->i_lock
);
59 __fsnotify_update_child_dentry_flags(inode
);
62 void fsnotify_destroy_inode_mark(struct fsnotify_mark
*mark
)
64 struct inode
*inode
= mark
->i
.inode
;
66 assert_spin_locked(&mark
->lock
);
67 assert_spin_locked(&mark
->group
->mark_lock
);
69 spin_lock(&inode
->i_lock
);
71 hlist_del_init_rcu(&mark
->i
.i_list
);
75 * this mark is now off the inode->i_fsnotify_marks list and we
76 * hold the inode->i_lock, so this is the perfect time to update the
77 * inode->i_fsnotify_mask
79 fsnotify_recalc_inode_mask_locked(inode
);
81 spin_unlock(&inode
->i_lock
);
85 * Given an inode, destroy all of the marks associated with that inode.
87 void fsnotify_clear_marks_by_inode(struct inode
*inode
)
89 struct fsnotify_mark
*mark
, *lmark
;
90 struct hlist_node
*pos
, *n
;
93 spin_lock(&inode
->i_lock
);
94 hlist_for_each_entry_safe(mark
, pos
, n
, &inode
->i_fsnotify_marks
, i
.i_list
) {
95 list_add(&mark
->i
.free_i_list
, &free_list
);
96 hlist_del_init_rcu(&mark
->i
.i_list
);
97 fsnotify_get_mark(mark
);
99 spin_unlock(&inode
->i_lock
);
101 list_for_each_entry_safe(mark
, lmark
, &free_list
, i
.free_i_list
) {
102 fsnotify_destroy_mark(mark
);
103 fsnotify_put_mark(mark
);
108 * Given a group clear all of the inode marks associated with that group.
110 void fsnotify_clear_inode_marks_by_group(struct fsnotify_group
*group
)
112 fsnotify_clear_marks_by_group_flags(group
, FSNOTIFY_MARK_FLAG_INODE
);
116 * given a group and inode, find the mark associated with that combination.
117 * if found take a reference to that mark and return it, else return NULL
119 static struct fsnotify_mark
*fsnotify_find_inode_mark_locked(
120 struct fsnotify_group
*group
,
123 struct fsnotify_mark
*mark
;
124 struct hlist_node
*pos
;
126 assert_spin_locked(&inode
->i_lock
);
128 hlist_for_each_entry(mark
, pos
, &inode
->i_fsnotify_marks
, i
.i_list
) {
129 if (mark
->group
== group
) {
130 fsnotify_get_mark(mark
);
138 * given a group and inode, find the mark associated with that combination.
139 * if found take a reference to that mark and return it, else return NULL
141 struct fsnotify_mark
*fsnotify_find_inode_mark(struct fsnotify_group
*group
,
144 struct fsnotify_mark
*mark
;
146 spin_lock(&inode
->i_lock
);
147 mark
= fsnotify_find_inode_mark_locked(group
, inode
);
148 spin_unlock(&inode
->i_lock
);
154 * If we are setting a mark mask on an inode mark we should pin the inode
157 void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark
*mark
,
162 assert_spin_locked(&mark
->lock
);
166 !(mark
->flags
& FSNOTIFY_MARK_FLAG_OBJECT_PINNED
)) {
167 mark
->flags
|= FSNOTIFY_MARK_FLAG_OBJECT_PINNED
;
168 inode
= igrab(mark
->i
.inode
);
170 * we shouldn't be able to get here if the inode wasn't
171 * already safely held in memory. But bug in case it
179 * Attach an initialized mark to a given inode.
180 * These marks may be used for the fsnotify backend to determine which
181 * event types should be delivered to which group and for which inodes. These
182 * marks are ordered according to priority, highest number first, and then by
183 * the group's location in memory.
185 int fsnotify_add_inode_mark(struct fsnotify_mark
*mark
,
186 struct fsnotify_group
*group
, struct inode
*inode
,
189 struct fsnotify_mark
*lmark
;
190 struct hlist_node
*node
, *last
= NULL
;
193 mark
->flags
|= FSNOTIFY_MARK_FLAG_INODE
;
195 assert_spin_locked(&mark
->lock
);
196 assert_spin_locked(&group
->mark_lock
);
198 spin_lock(&inode
->i_lock
);
200 mark
->i
.inode
= inode
;
202 /* is mark the first mark? */
203 if (hlist_empty(&inode
->i_fsnotify_marks
)) {
204 hlist_add_head_rcu(&mark
->i
.i_list
, &inode
->i_fsnotify_marks
);
208 /* should mark be in the middle of the current list? */
209 hlist_for_each_entry(lmark
, node
, &inode
->i_fsnotify_marks
, i
.i_list
) {
212 if ((lmark
->group
== group
) && !allow_dups
) {
217 if (mark
->group
->priority
< lmark
->group
->priority
)
220 if ((mark
->group
->priority
== lmark
->group
->priority
) &&
221 (mark
->group
< lmark
->group
))
224 hlist_add_before_rcu(&mark
->i
.i_list
, &lmark
->i
.i_list
);
228 BUG_ON(last
== NULL
);
229 /* mark should be the last entry. last is the current last entry */
230 hlist_add_after_rcu(last
, &mark
->i
.i_list
);
232 fsnotify_recalc_inode_mask_locked(inode
);
233 spin_unlock(&inode
->i_lock
);
239 * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
240 * @list: list of inodes being unmounted (sb->s_inodes)
242 * Called during unmount with no locks held, so needs to be safe against
243 * concurrent modifiers. We temporarily drop inode_sb_list_lock and CAN block.
245 void fsnotify_unmount_inodes(struct list_head
*list
)
247 struct inode
*inode
, *next_i
, *need_iput
= NULL
;
249 spin_lock(&inode_sb_list_lock
);
250 list_for_each_entry_safe(inode
, next_i
, list
, i_sb_list
) {
251 struct inode
*need_iput_tmp
;
254 * We cannot __iget() an inode in state I_FREEING,
255 * I_WILL_FREE, or I_NEW which is fine because by that point
256 * the inode cannot have any associated watches.
258 spin_lock(&inode
->i_lock
);
259 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
)) {
260 spin_unlock(&inode
->i_lock
);
265 * If i_count is zero, the inode cannot have any watches and
266 * doing an __iget/iput with MS_ACTIVE clear would actually
267 * evict all inodes with zero i_count from icache which is
268 * unnecessarily violent and may in fact be illegal to do.
270 if (!atomic_read(&inode
->i_count
)) {
271 spin_unlock(&inode
->i_lock
);
275 need_iput_tmp
= need_iput
;
278 /* In case fsnotify_inode_delete() drops a reference. */
279 if (inode
!= need_iput_tmp
)
282 need_iput_tmp
= NULL
;
283 spin_unlock(&inode
->i_lock
);
285 /* In case the dropping of a reference would nuke next_i. */
286 if ((&next_i
->i_sb_list
!= list
) &&
287 atomic_read(&next_i
->i_count
)) {
288 spin_lock(&next_i
->i_lock
);
289 if (!(next_i
->i_state
& (I_FREEING
| I_WILL_FREE
))) {
293 spin_unlock(&next_i
->i_lock
);
297 * We can safely drop inode_sb_list_lock here because we hold
298 * references on both inode and next_i. Also no new inodes
299 * will be added since the umount has begun.
301 spin_unlock(&inode_sb_list_lock
);
306 /* for each watch, send FS_UNMOUNT and then remove it */
307 fsnotify(inode
, FS_UNMOUNT
, inode
, FSNOTIFY_EVENT_INODE
, NULL
, 0);
309 fsnotify_inode_delete(inode
);
313 spin_lock(&inode_sb_list_lock
);
315 spin_unlock(&inode_sb_list_lock
);