tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
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>
25#include <linux/spinlock.h>
26
27#include <linux/atomic.h>
28
29#include <linux/fsnotify_backend.h>
30#include "fsnotify.h"
31#include "../mount.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 struct mount *m = real_mount(mnt);
38 LIST_HEAD(free_list);
39
40 spin_lock(&mnt->mnt_root->d_lock);
41 hlist_for_each_entry_safe(mark, pos, n, &m->mnt_fsnotify_marks, m.m_list) {
42 list_add(&mark->m.free_m_list, &free_list);
43 hlist_del_init_rcu(&mark->m.m_list);
44 fsnotify_get_mark(mark);
45 }
46 spin_unlock(&mnt->mnt_root->d_lock);
47
48 list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) {
49 fsnotify_destroy_mark(mark);
50 fsnotify_put_mark(mark);
51 }
52}
53
54void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
55{
56 fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
57}
58
59/*
60 * Recalculate the mask of events relevant to a given vfsmount locked.
61 */
62static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt)
63{
64 struct mount *m = real_mount(mnt);
65 struct fsnotify_mark *mark;
66 struct hlist_node *pos;
67 __u32 new_mask = 0;
68
69 assert_spin_locked(&mnt->mnt_root->d_lock);
70
71 hlist_for_each_entry(mark, pos, &m->mnt_fsnotify_marks, m.m_list)
72 new_mask |= mark->mask;
73 m->mnt_fsnotify_mask = new_mask;
74}
75
76/*
77 * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
78 * any notifier is interested in hearing for this mount point
79 */
80void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
81{
82 spin_lock(&mnt->mnt_root->d_lock);
83 fsnotify_recalc_vfsmount_mask_locked(mnt);
84 spin_unlock(&mnt->mnt_root->d_lock);
85}
86
87void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
88{
89 struct vfsmount *mnt = mark->m.mnt;
90
91 assert_spin_locked(&mark->lock);
92 assert_spin_locked(&mark->group->mark_lock);
93
94 spin_lock(&mnt->mnt_root->d_lock);
95
96 hlist_del_init_rcu(&mark->m.m_list);
97 mark->m.mnt = NULL;
98
99 fsnotify_recalc_vfsmount_mask_locked(mnt);
100
101 spin_unlock(&mnt->mnt_root->d_lock);
102}
103
104static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group,
105 struct vfsmount *mnt)
106{
107 struct mount *m = real_mount(mnt);
108 struct fsnotify_mark *mark;
109 struct hlist_node *pos;
110
111 assert_spin_locked(&mnt->mnt_root->d_lock);
112
113 hlist_for_each_entry(mark, pos, &m->mnt_fsnotify_marks, m.m_list) {
114 if (mark->group == group) {
115 fsnotify_get_mark(mark);
116 return mark;
117 }
118 }
119 return NULL;
120}
121
122/*
123 * given a group and vfsmount, find the mark associated with that combination.
124 * if found take a reference to that mark and return it, else return NULL
125 */
126struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
127 struct vfsmount *mnt)
128{
129 struct fsnotify_mark *mark;
130
131 spin_lock(&mnt->mnt_root->d_lock);
132 mark = fsnotify_find_vfsmount_mark_locked(group, mnt);
133 spin_unlock(&mnt->mnt_root->d_lock);
134
135 return mark;
136}
137
138/*
139 * Attach an initialized mark to a given group and vfsmount.
140 * These marks may be used for the fsnotify backend to determine which
141 * event types should be delivered to which groups.
142 */
143int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
144 struct fsnotify_group *group, struct vfsmount *mnt,
145 int allow_dups)
146{
147 struct mount *m = real_mount(mnt);
148 struct fsnotify_mark *lmark;
149 struct hlist_node *node, *last = NULL;
150 int ret = 0;
151
152 mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
153
154 assert_spin_locked(&mark->lock);
155 assert_spin_locked(&group->mark_lock);
156
157 spin_lock(&mnt->mnt_root->d_lock);
158
159 mark->m.mnt = mnt;
160
161 /* is mark the first mark? */
162 if (hlist_empty(&m->mnt_fsnotify_marks)) {
163 hlist_add_head_rcu(&mark->m.m_list, &m->mnt_fsnotify_marks);
164 goto out;
165 }
166
167 /* should mark be in the middle of the current list? */
168 hlist_for_each_entry(lmark, node, &m->mnt_fsnotify_marks, m.m_list) {
169 last = node;
170
171 if ((lmark->group == group) && !allow_dups) {
172 ret = -EEXIST;
173 goto out;
174 }
175
176 if (mark->group->priority < lmark->group->priority)
177 continue;
178
179 if ((mark->group->priority == lmark->group->priority) &&
180 (mark->group < lmark->group))
181 continue;
182
183 hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list);
184 goto out;
185 }
186
187 BUG_ON(last == NULL);
188 /* mark should be the last entry. last is the current last entry */
189 hlist_add_after_rcu(last, &mark->m.m_list);
190out:
191 fsnotify_recalc_vfsmount_mask_locked(mnt);
192 spin_unlock(&mnt->mnt_root->d_lock);
193
194 return ret;
195}