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);