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
fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group * group)32 void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
33 {
34 fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
35 }
36
37 /*
38 * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
39 * any notifier is interested in hearing for this mount point
40 */
fsnotify_recalc_vfsmount_mask(struct vfsmount * mnt)41 void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
42 {
43 struct mount *m = real_mount(mnt);
44
45 spin_lock(&mnt->mnt_root->d_lock);
46 m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
47 spin_unlock(&mnt->mnt_root->d_lock);
48 }
49
fsnotify_destroy_vfsmount_mark(struct fsnotify_mark * mark)50 void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
51 {
52 struct vfsmount *mnt = mark->mnt;
53 struct mount *m = real_mount(mnt);
54
55 BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
56 assert_spin_locked(&mark->lock);
57
58 spin_lock(&mnt->mnt_root->d_lock);
59
60 hlist_del_init_rcu(&mark->obj_list);
61 mark->mnt = NULL;
62
63 m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
64 spin_unlock(&mnt->mnt_root->d_lock);
65 }
66
67 /*
68 * given a group and vfsmount, find the mark associated with that combination.
69 * if found take a reference to that mark and return it, else return NULL
70 */
fsnotify_find_vfsmount_mark(struct fsnotify_group * group,struct vfsmount * mnt)71 struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
72 struct vfsmount *mnt)
73 {
74 struct mount *m = real_mount(mnt);
75 struct fsnotify_mark *mark;
76
77 spin_lock(&mnt->mnt_root->d_lock);
78 mark = fsnotify_find_mark(&m->mnt_fsnotify_marks, group);
79 spin_unlock(&mnt->mnt_root->d_lock);
80
81 return mark;
82 }
83
84 /*
85 * Attach an initialized mark to a given group and vfsmount.
86 * These marks may be used for the fsnotify backend to determine which
87 * event types should be delivered to which groups.
88 */
fsnotify_add_vfsmount_mark(struct fsnotify_mark * mark,struct fsnotify_group * group,struct vfsmount * mnt,int allow_dups)89 int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
90 struct fsnotify_group *group, struct vfsmount *mnt,
91 int allow_dups)
92 {
93 struct mount *m = real_mount(mnt);
94 int ret;
95
96 mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
97
98 BUG_ON(!mutex_is_locked(&group->mark_mutex));
99 assert_spin_locked(&mark->lock);
100
101 spin_lock(&mnt->mnt_root->d_lock);
102 mark->mnt = mnt;
103 ret = fsnotify_add_mark_list(&m->mnt_fsnotify_marks, mark, allow_dups);
104 m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
105 spin_unlock(&mnt->mnt_root->d_lock);
106
107 return ret;
108 }
109