summaryrefslogtreecommitdiffstats
path: root/fs/notify/inotify/inotify_fsnotify.c
blob: 1afb0a10229f448b55be812d2d1939817250cf77 (plain)
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
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/*
 * fs/inotify_user.c - inotify support for userspace
 *
 * Authors:
 *	John McCutchan	<ttb@tentacle.dhs.org>
 *	Robert Love	<rml@novell.com>
 *
 * Copyright (C) 2005 John McCutchan
 * Copyright 2006 Hewlett-Packard Development Company, L.P.
 *
 * Copyright (C) 2009 Eric Paris <Red Hat Inc>
 * inotify was largely rewriten to make use of the fsnotify infrastructure
 *
 * 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.
 */

#include <linux/fs.h> /* struct inode */
#include <linux/fsnotify_backend.h>
#include <linux/inotify.h>
#include <linux/path.h> /* struct path */
#include <linux/slab.h> /* kmem_* */
#include <linux/types.h>

#include "inotify.h"

static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
{
	struct fsnotify_mark_entry *entry;
	struct inotify_inode_mark_entry *ientry;
	struct inode *to_tell;
	struct inotify_event_private_data *event_priv;
	struct fsnotify_event_private_data *fsn_event_priv;
	int wd, ret;

	to_tell = event->to_tell;

	spin_lock(&to_tell->i_lock);
	entry = fsnotify_find_mark_entry(group, to_tell);
	spin_unlock(&to_tell->i_lock);
	/* race with watch removal?  We already passes should_send */
	if (unlikely(!entry))
		return 0;
	ientry = container_of(entry, struct inotify_inode_mark_entry,
			      fsn_entry);
	wd = ientry->wd;

	event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL);
	if (unlikely(!event_priv))
		return -ENOMEM;

	fsn_event_priv = &event_priv->fsnotify_event_priv_data;

	fsn_event_priv->group = group;
	event_priv->wd = wd;

	ret = fsnotify_add_notify_event(group, event, fsn_event_priv);
	if (ret) {
		inotify_free_event_priv(fsn_event_priv);
		/* EEXIST says we tail matched, EOVERFLOW isn't something
		 * to report up the stack. */
		if ((ret == -EEXIST) ||
		    (ret == -EOVERFLOW))
			ret = 0;
	}

	/*
	 * If we hold the entry until after the event is on the queue
	 * IN_IGNORED won't be able to pass this event in the queue
	 */
	fsnotify_put_mark(entry);

	return ret;
}

static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group)
{
	inotify_ignored_and_remove_idr(entry, group);
}

static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask)
{
	struct fsnotify_mark_entry *entry;
	bool send;

	spin_lock(&inode->i_lock);
	entry = fsnotify_find_mark_entry(group, inode);
	spin_unlock(&inode->i_lock);
	if (!entry)
		return false;

	mask = (mask & ~FS_EVENT_ON_CHILD);
	send = (entry->mask & mask);

	/* find took a reference */
	fsnotify_put_mark(entry);

	return send;
}

/*
 * This is NEVER supposed to be called.  Inotify marks should either have been
 * removed from the idr when the watch was removed or in the
 * fsnotify_destroy_mark_by_group() call when the inotify instance was being
 * torn down.  This is only called if the idr is about to be freed but there
 * are still marks in it.
 */
static int idr_callback(int id, void *p, void *data)
{
	struct fsnotify_mark_entry *entry;
	struct inotify_inode_mark_entry *ientry;
	static bool warned = false;

	if (warned)
		return 0;

	warned = true;
	entry = p;
	ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);

	WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in "
		"idr.  Probably leaking memory\n", id, p, data);

	/*
	 * I'm taking the liberty of assuming that the mark in question is a
	 * valid address and I'm dereferencing it.  This might help to figure
	 * out why we got here and the panic is no worse than the original
	 * BUG() that was here.
	 */
	if (entry)
		printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n",
			entry->group, entry->inode, ientry->wd);
	return 0;
}

static void inotify_free_group_priv(struct fsnotify_group *group)
{
	/* ideally the idr is empty and we won't hit the BUG in teh callback */
	idr_for_each(&group->inotify_data.idr, idr_callback, group);
	idr_remove_all(&group->inotify_data.idr);
	idr_destroy(&group->inotify_data.idr);
}

void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv)
{
	struct inotify_event_private_data *event_priv;


	event_priv = container_of(fsn_event_priv, struct inotify_event_private_data,
				  fsnotify_event_priv_data);

	kmem_cache_free(event_priv_cachep, event_priv);
}

const struct fsnotify_ops inotify_fsnotify_ops = {
	.handle_event = inotify_handle_event,
	.should_send_event = inotify_should_send_event,
	.free_group_priv = inotify_free_group_priv,
	.free_event_priv = inotify_free_event_priv,
	.freeing_mark = inotify_freeing_mark,
};
OpenPOWER on IntegriCloud