blob: 56772b578fbd546d62a199ad25f6b1dec859e660 [file] [log] [blame]
Eric Paris0d48b7f2009-12-17 21:24:27 -05001/*
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
19#include <linux/fs.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/mount.h>
24#include <linux/mutex.h>
Eric Paris0d48b7f2009-12-17 21:24:27 -050025#include <linux/spinlock.h>
26#include <linux/writeback.h> /* for inode_lock */
27
28#include <asm/atomic.h>
29
30#include <linux/fsnotify_backend.h>
31#include "fsnotify.h"
32
33void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
34{
35 struct fsnotify_mark *mark, *lmark;
36 struct hlist_node *pos, *n;
37 LIST_HEAD(free_list);
38
39 spin_lock(&mnt->mnt_root->d_lock);
40 hlist_for_each_entry_safe(mark, pos, n, &mnt->mnt_fsnotify_marks, m.m_list) {
41 list_add(&mark->m.free_m_list, &free_list);
Eric Parisa4c6e992010-07-28 10:18:38 -040042 hlist_del_init_rcu(&mark->m.m_list);
Eric Paris0d48b7f2009-12-17 21:24:27 -050043 fsnotify_get_mark(mark);
44 }
45 spin_unlock(&mnt->mnt_root->d_lock);
46
47 list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) {
48 fsnotify_destroy_mark(mark);
49 fsnotify_put_mark(mark);
50 }
51}
52
Eric Paris4d926042009-12-17 21:24:34 -050053void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
54{
55 fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
56}
57
Eric Paris0d48b7f2009-12-17 21:24:27 -050058/*
59 * Recalculate the mask of events relevant to a given vfsmount locked.
60 */
61static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt)
62{
63 struct fsnotify_mark *mark;
64 struct hlist_node *pos;
65 __u32 new_mask = 0;
66
67 assert_spin_locked(&mnt->mnt_root->d_lock);
68
69 hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list)
70 new_mask |= mark->mask;
71 mnt->mnt_fsnotify_mask = new_mask;
72}
73
74/*
75 * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
76 * any notifier is interested in hearing for this mount point
77 */
78void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
79{
80 spin_lock(&mnt->mnt_root->d_lock);
81 fsnotify_recalc_vfsmount_mask_locked(mnt);
82 spin_unlock(&mnt->mnt_root->d_lock);
83}
84
85void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
86{
87 struct vfsmount *mnt = mark->m.mnt;
88
89 assert_spin_locked(&mark->lock);
90 assert_spin_locked(&mark->group->mark_lock);
91
92 spin_lock(&mnt->mnt_root->d_lock);
93
Eric Parisa4c6e992010-07-28 10:18:38 -040094 hlist_del_init_rcu(&mark->m.m_list);
Eric Paris0d48b7f2009-12-17 21:24:27 -050095 mark->m.mnt = NULL;
96
97 fsnotify_recalc_vfsmount_mask_locked(mnt);
98
99 spin_unlock(&mnt->mnt_root->d_lock);
100}
101
102static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group,
103 struct vfsmount *mnt)
104{
105 struct fsnotify_mark *mark;
106 struct hlist_node *pos;
107
108 assert_spin_locked(&mnt->mnt_root->d_lock);
109
110 hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) {
111 if (mark->group == group) {
112 fsnotify_get_mark(mark);
113 return mark;
114 }
115 }
116 return NULL;
117}
118
119/*
120 * given a group and vfsmount, find the mark associated with that combination.
121 * if found take a reference to that mark and return it, else return NULL
122 */
123struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
124 struct vfsmount *mnt)
125{
126 struct fsnotify_mark *mark;
127
128 spin_lock(&mnt->mnt_root->d_lock);
129 mark = fsnotify_find_vfsmount_mark_locked(group, mnt);
130 spin_unlock(&mnt->mnt_root->d_lock);
131
132 return mark;
133}
134
135/*
136 * Attach an initialized mark to a given group and vfsmount.
137 * These marks may be used for the fsnotify backend to determine which
138 * event types should be delivered to which groups.
139 */
140int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
141 struct fsnotify_group *group, struct vfsmount *mnt,
142 int allow_dups)
143{
Eric Paris0c6532e2010-07-28 10:18:38 -0400144 struct fsnotify_mark *lmark;
145 struct hlist_node *node, *last = NULL;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500146 int ret = 0;
147
Eric Paris700307a2010-07-28 10:18:38 -0400148 mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500149
Eric Paris0d48b7f2009-12-17 21:24:27 -0500150 assert_spin_locked(&mark->lock);
151 assert_spin_locked(&group->mark_lock);
152
153 spin_lock(&mnt->mnt_root->d_lock);
154
Eric Paris0c6532e2010-07-28 10:18:38 -0400155 mark->m.mnt = mnt;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500156
Eric Paris0c6532e2010-07-28 10:18:38 -0400157 /* is mark the first mark? */
158 if (hlist_empty(&mnt->mnt_fsnotify_marks)) {
Eric Parisa4c6e992010-07-28 10:18:38 -0400159 hlist_add_head_rcu(&mark->m.m_list, &mnt->mnt_fsnotify_marks);
Eric Paris0c6532e2010-07-28 10:18:38 -0400160 goto out;
Eric Paris0d48b7f2009-12-17 21:24:27 -0500161 }
162
Eric Paris0c6532e2010-07-28 10:18:38 -0400163 /* should mark be in the middle of the current list? */
164 hlist_for_each_entry(lmark, node, &mnt->mnt_fsnotify_marks, m.m_list) {
165 last = node;
166
167 if ((lmark->group == group) && !allow_dups) {
168 ret = -EEXIST;
169 goto out;
170 }
171
172 if (mark->group < lmark->group)
173 continue;
174
Eric Parisa4c6e992010-07-28 10:18:38 -0400175 hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400176 goto out;
177 }
178
179 BUG_ON(last == NULL);
180 /* mark should be the last entry. last is the current last entry */
Eric Parisa4c6e992010-07-28 10:18:38 -0400181 hlist_add_after_rcu(last, &mark->m.m_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400182out:
183 fsnotify_recalc_vfsmount_mask_locked(mnt);
Eric Paris0d48b7f2009-12-17 21:24:27 -0500184 spin_unlock(&mnt->mnt_root->d_lock);
185
186 return ret;
187}