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;
36	struct hlist_node *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, n, &m->mnt_fsnotify_marks, obj_list) {
42		list_add(&mark->free_list, &free_list);
43		hlist_del_init_rcu(&mark->obj_list);
44		fsnotify_get_mark(mark);
45	}
46	spin_unlock(&mnt->mnt_root->d_lock);
47
48	fsnotify_destroy_marks(&free_list);
49}
50
51void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group)
52{
53	fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT);
54}
55
56/*
57 * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types
58 * any notifier is interested in hearing for this mount point
59 */
60void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt)
61{
62	struct mount *m = real_mount(mnt);
63
64	spin_lock(&mnt->mnt_root->d_lock);
65	m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
66	spin_unlock(&mnt->mnt_root->d_lock);
67}
68
69void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
70{
71	struct vfsmount *mnt = mark->mnt;
72	struct mount *m = real_mount(mnt);
73
74	BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
75	assert_spin_locked(&mark->lock);
76
77	spin_lock(&mnt->mnt_root->d_lock);
78
79	hlist_del_init_rcu(&mark->obj_list);
80	mark->mnt = NULL;
81
82	m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
83	spin_unlock(&mnt->mnt_root->d_lock);
84}
85
86/*
87 * given a group and vfsmount, find the mark associated with that combination.
88 * if found take a reference to that mark and return it, else return NULL
89 */
90struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
91						  struct vfsmount *mnt)
92{
93	struct mount *m = real_mount(mnt);
94	struct fsnotify_mark *mark;
95
96	spin_lock(&mnt->mnt_root->d_lock);
97	mark = fsnotify_find_mark(&m->mnt_fsnotify_marks, group);
98	spin_unlock(&mnt->mnt_root->d_lock);
99
100	return mark;
101}
102
103/*
104 * Attach an initialized mark to a given group and vfsmount.
105 * These marks may be used for the fsnotify backend to determine which
106 * event types should be delivered to which groups.
107 */
108int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
109			       struct fsnotify_group *group, struct vfsmount *mnt,
110			       int allow_dups)
111{
112	struct mount *m = real_mount(mnt);
113	int ret;
114
115	mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
116
117	BUG_ON(!mutex_is_locked(&group->mark_mutex));
118	assert_spin_locked(&mark->lock);
119
120	spin_lock(&mnt->mnt_root->d_lock);
121	mark->mnt = mnt;
122	ret = fsnotify_add_mark_list(&m->mnt_fsnotify_marks, mark, allow_dups);
123	m->mnt_fsnotify_mask = fsnotify_recalc_mask(&m->mnt_fsnotify_marks);
124	spin_unlock(&mnt->mnt_root->d_lock);
125
126	return ret;
127}
128