blob: ad199598045655105e7ba4db0ed639357bf3fc6f [file] [log] [blame]
Eric Paris90586522009-05-21 17:01:20 -04001/*
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/list.h>
20#include <linux/mutex.h>
21#include <linux/slab.h>
22#include <linux/srcu.h>
23#include <linux/rculist.h>
24#include <linux/wait.h>
25
26#include <linux/fsnotify_backend.h>
27#include "fsnotify.h"
28
Arun Sharma600634972011-07-26 16:09:06 -070029#include <linux/atomic.h>
Eric Paris90586522009-05-21 17:01:20 -040030
Eric Paris3be25f42009-05-21 17:01:26 -040031/*
Eric Paris90586522009-05-21 17:01:20 -040032 * Final freeing of a group
33 */
Eric Paris3be25f42009-05-21 17:01:26 -040034void fsnotify_final_destroy_group(struct fsnotify_group *group)
Eric Paris90586522009-05-21 17:01:20 -040035{
36 if (group->ops->free_group_priv)
37 group->ops->free_group_priv(group);
38
39 kfree(group);
40}
41
42/*
Lino Sanfilippo23e964c2011-06-14 17:29:47 +020043 * Trying to get rid of a group. Remove all marks, flush all events and release
44 * the group reference.
45 * Note that another thread calling fsnotify_clear_marks_by_group() may still
46 * hold a ref to the group.
Eric Paris3be25f42009-05-21 17:01:26 -040047 */
Lino Sanfilippod8153d42011-06-14 17:29:45 +020048void fsnotify_destroy_group(struct fsnotify_group *group)
Eric Paris3be25f42009-05-21 17:01:26 -040049{
Eric Parise61ce862009-12-17 21:24:24 -050050 /* clear all inode marks for this group */
Eric Paris3be25f42009-05-21 17:01:26 -040051 fsnotify_clear_marks_by_group(group);
52
Eric Paris75c1be42010-07-28 10:18:38 -040053 synchronize_srcu(&fsnotify_mark_srcu);
54
Lino Sanfilippo23e964c2011-06-14 17:29:47 +020055 /* clear the notification queue of all events */
56 fsnotify_flush_notify(group);
57
Jan Karaff57cd52014-02-21 19:14:11 +010058 /*
59 * Destroy overflow event (we cannot use fsnotify_destroy_event() as
60 * that deliberately ignores overflow events.
61 */
62 if (group->overflow_event)
63 group->ops->free_event(group->overflow_event);
64
Lino Sanfilippo23e964c2011-06-14 17:29:47 +020065 fsnotify_put_group(group);
Eric Paris3be25f42009-05-21 17:01:26 -040066}
67
68/*
Lino Sanfilippo98612952011-06-14 17:29:46 +020069 * Get reference to a group.
70 */
71void fsnotify_get_group(struct fsnotify_group *group)
72{
73 atomic_inc(&group->refcnt);
74}
75
76/*
Eric Paris90586522009-05-21 17:01:20 -040077 * Drop a reference to a group. Free it if it's through.
78 */
79void fsnotify_put_group(struct fsnotify_group *group)
80{
Eric Paris02436662010-07-28 10:18:39 -040081 if (atomic_dec_and_test(&group->refcnt))
Lino Sanfilippo23e964c2011-06-14 17:29:47 +020082 fsnotify_final_destroy_group(group);
Eric Paris90586522009-05-21 17:01:20 -040083}
84
85/*
Eric Parisffab8342009-12-17 21:24:22 -050086 * Create a new fsnotify_group and hold a reference for the group returned.
Eric Paris90586522009-05-21 17:01:20 -040087 */
Eric Paris0d2e2a12009-12-17 21:24:22 -050088struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
Eric Paris90586522009-05-21 17:01:20 -040089{
Eric Paris74be0cc2009-12-17 21:24:22 -050090 struct fsnotify_group *group;
Eric Paris90586522009-05-21 17:01:20 -040091
Eric Parisf0553af2009-12-17 20:12:06 -050092 group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
Eric Paris90586522009-05-21 17:01:20 -040093 if (!group)
94 return ERR_PTR(-ENOMEM);
95
Eric Paris36fddeb2009-12-17 21:24:23 -050096 /* set to 0 when there a no external references to this group */
Eric Paris90586522009-05-21 17:01:20 -040097 atomic_set(&group->refcnt, 1);
Lino Sanfilippo23e964c2011-06-14 17:29:47 +020098 atomic_set(&group->num_marks, 0);
Eric Paris36fddeb2009-12-17 21:24:23 -050099
Eric Parisa2d8bc62009-05-21 17:01:37 -0400100 mutex_init(&group->notification_mutex);
101 INIT_LIST_HEAD(&group->notification_list);
102 init_waitqueue_head(&group->notification_waitq);
Eric Parisa2d8bc62009-05-21 17:01:37 -0400103 group->max_events = UINT_MAX;
104
Lino Sanfilippo986ab092011-06-14 17:29:50 +0200105 mutex_init(&group->mark_mutex);
Eric Parise61ce862009-12-17 21:24:24 -0500106 INIT_LIST_HEAD(&group->marks_list);
Eric Paris3be25f42009-05-21 17:01:26 -0400107
Eric Paris90586522009-05-21 17:01:20 -0400108 group->ops = ops;
109
Eric Paris90586522009-05-21 17:01:20 -0400110 return group;
111}
Eric Paris0a6b6bd2011-10-14 17:43:39 -0400112
113int fsnotify_fasync(int fd, struct file *file, int on)
114{
115 struct fsnotify_group *group = file->private_data;
116
117 return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO;
118}