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>
25 #include <linux/writeback.h> /* for inode_lock */
27 #include <asm/atomic.h>
29 #include <linux/fsnotify_backend.h>
33 * Recalculate the mask of events relevant to a given inode locked.
35 static void fsnotify_recalc_inode_mask_locked(struct inode *inode)
37 struct fsnotify_mark *mark;
38 struct hlist_node *pos;
41 assert_spin_locked(&inode->i_lock);
43 hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list)
44 new_mask |= mark->mask;
45 inode->i_fsnotify_mask = new_mask;
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.
52 void fsnotify_recalc_inode_mask(struct inode *inode)
54 spin_lock(&inode->i_lock);
55 fsnotify_recalc_inode_mask_locked(inode);
56 spin_unlock(&inode->i_lock);
58 __fsnotify_update_child_dentry_flags(inode);
61 void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
63 struct inode *inode = mark->i.inode;
65 assert_spin_locked(&mark->lock);
66 assert_spin_locked(&mark->group->mark_lock);
68 spin_lock(&inode->i_lock);
70 hlist_del_init(&mark->i.i_list);
74 * this mark is now off the inode->i_fsnotify_marks list and we
75 * hold the inode->i_lock, so this is the perfect time to update the
76 * inode->i_fsnotify_mask
78 fsnotify_recalc_inode_mask_locked(inode);
80 spin_unlock(&inode->i_lock);
84 * Given an inode, destroy all of the marks associated with that inode.
86 void fsnotify_clear_marks_by_inode(struct inode *inode)
88 struct fsnotify_mark *mark, *lmark;
89 struct hlist_node *pos, *n;
92 spin_lock(&inode->i_lock);
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);
98 spin_unlock(&inode->i_lock);
100 list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) {
101 fsnotify_destroy_mark(mark);
102 fsnotify_put_mark(mark);
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
110 struct fsnotify_mark *fsnotify_find_inode_mark_locked(struct fsnotify_group *group,
113 struct fsnotify_mark *mark;
114 struct hlist_node *pos;
116 assert_spin_locked(&inode->i_lock);
118 hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) {
119 if (mark->group == group) {
120 fsnotify_get_mark(mark);
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
131 struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group,
134 struct fsnotify_mark *mark;
136 spin_lock(&inode->i_lock);
137 mark = fsnotify_find_inode_mark_locked(group, inode);
138 spin_unlock(&inode->i_lock);
144 * Attach an initialized mark mark to a given group and inode.
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.
148 int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
149 struct fsnotify_group *group, struct inode *inode,
152 struct fsnotify_mark *lmark = NULL;
155 inode = igrab(inode);
156 if (unlikely(!inode))
159 mark->flags = FSNOTIFY_MARK_FLAG_INODE;
161 assert_spin_locked(&mark->lock);
162 assert_spin_locked(&group->mark_lock);
164 spin_lock(&inode->i_lock);
167 lmark = fsnotify_find_inode_mark_locked(group, inode);
169 mark->i.inode = inode;
171 hlist_add_head(&mark->i.i_list, &inode->i_fsnotify_marks);
173 fsnotify_recalc_inode_mask_locked(inode);
176 spin_unlock(&inode->i_lock);
187 * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
188 * @list: list of inodes being unmounted (sb->s_inodes)
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.
194 void fsnotify_unmount_inodes(struct list_head *list)
196 struct inode *inode, *next_i, *need_iput = NULL;
198 list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
199 struct inode *need_iput_tmp;
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.
206 if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW))
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.
215 if (!atomic_read(&inode->i_count))
218 need_iput_tmp = need_iput;
221 /* In case fsnotify_inode_delete() drops a reference. */
222 if (inode != need_iput_tmp)
225 need_iput_tmp = NULL;
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))) {
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.
241 spin_unlock(&inode_lock);
246 /* for each watch, send FS_UNMOUNT and then remove it */
247 fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
249 fsnotify_inode_delete(inode);
253 spin_lock(&inode_lock);