1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
/*
* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <asm/atomic.h>
#include <linux/fsnotify_backend.h>
#include "fsnotify.h"
void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
{
struct fsnotify_mark *mark, *lmark;
struct hlist_node *pos, *n;
LIST_HEAD(free_list);
spin_lock(&mnt->mnt_root->d_lock);
hlist_for_each_entry_safe(mark, pos, n, &mnt->mnt_fsnotify_marks, m.m_list) {
list_add(&mark->m.free_m_list, &free_list);
hlist_del_init_rcu(&mark->m.m_list);
fsnotify_get_mark(mark);
}
spin_unlock(&mnt->mnt_root->d_lock);
list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) {
fsnotify_destroy_mark(mark);
fsnotify_put_mark(mark);
}
}
void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
{
fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
}
/*
* Recalculate the mask of events relevant to a given vfsmount locked.
*/
static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt)
{
struct fsnotify_mark *mark;
struct hlist_node *pos;
__u32 new_mask = 0;
assert_spin_locked(&mnt->mnt_root->d_lock);
hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list)
new_mask |= mark->mask;
mnt->mnt_fsnotify_mask = new_mask;
}
/*
* Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
* any notifier is interested in hearing for this mount point
*/
void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
{
spin_lock(&mnt->mnt_root->d_lock);
fsnotify_recalc_vfsmount_mask_locked(mnt);
spin_unlock(&mnt->mnt_root->d_lock);
}
void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
{
struct vfsmount *mnt = mark->m.mnt;
assert_spin_locked(&mark->lock);
assert_spin_locked(&mark->group->mark_lock);
spin_lock(&mnt->mnt_root->d_lock);
hlist_del_init_rcu(&mark->m.m_list);
mark->m.mnt = NULL;
fsnotify_recalc_vfsmount_mask_locked(mnt);
spin_unlock(&mnt->mnt_root->d_lock);
}
static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group,
struct vfsmount *mnt)
{
struct fsnotify_mark *mark;
struct hlist_node *pos;
assert_spin_locked(&mnt->mnt_root->d_lock);
hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) {
if (mark->group == group) {
fsnotify_get_mark(mark);
return mark;
}
}
return NULL;
}
/*
* given a group and vfsmount, find the mark associated with that combination.
* if found take a reference to that mark and return it, else return NULL
*/
struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
struct vfsmount *mnt)
{
struct fsnotify_mark *mark;
spin_lock(&mnt->mnt_root->d_lock);
mark = fsnotify_find_vfsmount_mark_locked(group, mnt);
spin_unlock(&mnt->mnt_root->d_lock);
return mark;
}
/*
* Attach an initialized mark to a given group and vfsmount.
* These marks may be used for the fsnotify backend to determine which
* event types should be delivered to which groups.
*/
int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group, struct vfsmount *mnt,
int allow_dups)
{
struct fsnotify_mark *lmark;
struct hlist_node *node, *last = NULL;
int ret = 0;
mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
assert_spin_locked(&mark->lock);
assert_spin_locked(&group->mark_lock);
spin_lock(&mnt->mnt_root->d_lock);
mark->m.mnt = mnt;
/* is mark the first mark? */
if (hlist_empty(&mnt->mnt_fsnotify_marks)) {
hlist_add_head_rcu(&mark->m.m_list, &mnt->mnt_fsnotify_marks);
goto out;
}
/* should mark be in the middle of the current list? */
hlist_for_each_entry(lmark, node, &mnt->mnt_fsnotify_marks, m.m_list) {
last = node;
if ((lmark->group == group) && !allow_dups) {
ret = -EEXIST;
goto out;
}
if (mark->group->priority < lmark->group->priority)
continue;
if ((mark->group->priority == lmark->group->priority) &&
(mark->group < lmark->group))
continue;
hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list);
goto out;
}
BUG_ON(last == NULL);
/* mark should be the last entry. last is the current last entry */
hlist_add_after_rcu(last, &mark->m.m_list);
out:
fsnotify_recalc_vfsmount_mask_locked(mnt);
spin_unlock(&mnt->mnt_root->d_lock);
return ret;
}
|