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
|
/*
* 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/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/srcu.h>
#include <linux/rculist.h>
#include <linux/wait.h>
#include <linux/fsnotify_backend.h>
#include "fsnotify.h"
#include <linux/atomic.h>
/*
* Final freeing of a group
*/
static void fsnotify_final_destroy_group(struct fsnotify_group *group)
{
if (group->ops->free_group_priv)
group->ops->free_group_priv(group);
kfree(group);
}
/*
* Trying to get rid of a group. Remove all marks, flush all events and release
* the group reference.
* Note that another thread calling fsnotify_clear_marks_by_group() may still
* hold a ref to the group.
*/
void fsnotify_destroy_group(struct fsnotify_group *group)
{
/* clear all inode marks for this group */
fsnotify_clear_marks_by_group(group);
synchronize_srcu(&fsnotify_mark_srcu);
/* clear the notification queue of all events */
fsnotify_flush_notify(group);
/*
* Destroy overflow event (we cannot use fsnotify_destroy_event() as
* that deliberately ignores overflow events.
*/
if (group->overflow_event)
group->ops->free_event(group->overflow_event);
fsnotify_put_group(group);
}
/*
* Get reference to a group.
*/
void fsnotify_get_group(struct fsnotify_group *group)
{
atomic_inc(&group->refcnt);
}
/*
* Drop a reference to a group. Free it if it's through.
*/
void fsnotify_put_group(struct fsnotify_group *group)
{
if (atomic_dec_and_test(&group->refcnt))
fsnotify_final_destroy_group(group);
}
/*
* Create a new fsnotify_group and hold a reference for the group returned.
*/
struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
{
struct fsnotify_group *group;
group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
if (!group)
return ERR_PTR(-ENOMEM);
/* set to 0 when there a no external references to this group */
atomic_set(&group->refcnt, 1);
atomic_set(&group->num_marks, 0);
mutex_init(&group->notification_mutex);
INIT_LIST_HEAD(&group->notification_list);
init_waitqueue_head(&group->notification_waitq);
group->max_events = UINT_MAX;
mutex_init(&group->mark_mutex);
INIT_LIST_HEAD(&group->marks_list);
group->ops = ops;
return group;
}
int fsnotify_fasync(int fd, struct file *file, int on)
{
struct fsnotify_group *group = file->private_data;
return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO;
}
|
