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Eric Paris63c882a2009-05-21 17:02:01 -04001/*
2 * fs/inotify_user.c - inotify support for userspace
3 *
4 * Authors:
5 * John McCutchan <ttb@tentacle.dhs.org>
6 * Robert Love <rml@novell.com>
7 *
8 * Copyright (C) 2005 John McCutchan
9 * Copyright 2006 Hewlett-Packard Development Company, L.P.
10 *
11 * Copyright (C) 2009 Eric Paris <Red Hat Inc>
12 * inotify was largely rewriten to make use of the fsnotify infrastructure
13 *
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2, or (at your option) any
17 * later version.
18 *
19 * This program is distributed in the hope that it will be useful, but
20 * WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 * General Public License for more details.
23 */
24
Eric Paris8c1934c2010-07-28 10:18:37 -040025#include <linux/dcache.h> /* d_unlinked */
Eric Paris63c882a2009-05-21 17:02:01 -040026#include <linux/fs.h> /* struct inode */
27#include <linux/fsnotify_backend.h>
28#include <linux/inotify.h>
29#include <linux/path.h> /* struct path */
30#include <linux/slab.h> /* kmem_* */
31#include <linux/types.h>
Pavel Emelyanovb3b38d82010-05-12 15:34:07 -070032#include <linux/sched.h>
Eric Paris63c882a2009-05-21 17:02:01 -040033
34#include "inotify.h"
35
Eric Paris74766bb2009-12-17 21:24:21 -050036/*
37 * Check if 2 events contain the same information. We do not compare private data
38 * but at this moment that isn't a problem for any know fsnotify listeners.
39 */
40static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new)
41{
42 if ((old->mask == new->mask) &&
43 (old->to_tell == new->to_tell) &&
44 (old->data_type == new->data_type) &&
45 (old->name_len == new->name_len)) {
46 switch (old->data_type) {
47 case (FSNOTIFY_EVENT_INODE):
48 /* remember, after old was put on the wait_q we aren't
49 * allowed to look at the inode any more, only thing
50 * left to check was if the file_name is the same */
51 if (!old->name_len ||
52 !strcmp(old->file_name, new->file_name))
53 return true;
54 break;
Eric Paris3bcf3862010-07-28 10:18:37 -040055 case (FSNOTIFY_EVENT_FILE):
56 if ((old->file->f_path.mnt == new->file->f_path.mnt) &&
57 (old->file->f_path.dentry == new->file->f_path.dentry))
Eric Paris74766bb2009-12-17 21:24:21 -050058 return true;
59 break;
60 case (FSNOTIFY_EVENT_NONE):
61 if (old->mask & FS_Q_OVERFLOW)
62 return true;
63 else if (old->mask & FS_IN_IGNORED)
64 return false;
65 return true;
66 };
67 }
68 return false;
69}
70
Eric Parisf70ab542010-07-28 10:18:37 -040071static struct fsnotify_event *inotify_merge(struct list_head *list,
72 struct fsnotify_event *event)
Eric Paris74766bb2009-12-17 21:24:21 -050073{
74 struct fsnotify_event_holder *last_holder;
75 struct fsnotify_event *last_event;
Eric Paris74766bb2009-12-17 21:24:21 -050076
77 /* and the list better be locked by something too */
78 spin_lock(&event->lock);
79
80 last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list);
81 last_event = last_holder->event;
82 if (event_compare(last_event, event))
Eric Parisf70ab542010-07-28 10:18:37 -040083 fsnotify_get_event(last_event);
84 else
85 last_event = NULL;
Eric Paris74766bb2009-12-17 21:24:21 -050086
87 spin_unlock(&event->lock);
88
Eric Parisf70ab542010-07-28 10:18:37 -040089 return last_event;
Eric Paris74766bb2009-12-17 21:24:21 -050090}
91
Eric Paris3a9b16b2010-07-28 10:18:38 -040092static int inotify_handle_event(struct fsnotify_group *group,
93 struct fsnotify_mark *mark,
94 struct fsnotify_event *event)
Eric Paris63c882a2009-05-21 17:02:01 -040095{
Eric Paris000285d2009-12-17 21:24:24 -050096 struct fsnotify_mark *fsn_mark;
97 struct inotify_inode_mark *i_mark;
Eric Paris63c882a2009-05-21 17:02:01 -040098 struct inode *to_tell;
99 struct inotify_event_private_data *event_priv;
100 struct fsnotify_event_private_data *fsn_event_priv;
Eric Parisf70ab542010-07-28 10:18:37 -0400101 struct fsnotify_event *added_event;
102 int wd, ret = 0;
Eric Paris63c882a2009-05-21 17:02:01 -0400103
Eric Paris5ba08e22010-07-28 10:18:37 -0400104 pr_debug("%s: group=%p event=%p to_tell=%p mask=%x\n", __func__, group,
105 event, event->to_tell, event->mask);
106
Eric Paris63c882a2009-05-21 17:02:01 -0400107 to_tell = event->to_tell;
108
Eric Paris5444e292009-12-17 21:24:27 -0500109 fsn_mark = fsnotify_find_inode_mark(group, to_tell);
Eric Paris63c882a2009-05-21 17:02:01 -0400110 /* race with watch removal? We already passes should_send */
Eric Paris000285d2009-12-17 21:24:24 -0500111 if (unlikely(!fsn_mark))
Eric Paris63c882a2009-05-21 17:02:01 -0400112 return 0;
Eric Paris000285d2009-12-17 21:24:24 -0500113 i_mark = container_of(fsn_mark, struct inotify_inode_mark,
114 fsn_mark);
115 wd = i_mark->wd;
Eric Paris63c882a2009-05-21 17:02:01 -0400116
117 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL);
118 if (unlikely(!event_priv))
119 return -ENOMEM;
120
121 fsn_event_priv = &event_priv->fsnotify_event_priv_data;
122
123 fsn_event_priv->group = group;
124 event_priv->wd = wd;
125
Eric Parisf70ab542010-07-28 10:18:37 -0400126 added_event = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge);
127 if (added_event) {
Eric Paris63c882a2009-05-21 17:02:01 -0400128 inotify_free_event_priv(fsn_event_priv);
Eric Parisf70ab542010-07-28 10:18:37 -0400129 if (!IS_ERR(added_event))
130 fsnotify_put_event(added_event);
131 else
132 ret = PTR_ERR(added_event);
Eric Pariseef3a112009-08-16 21:51:44 -0400133 }
Eric Paris63c882a2009-05-21 17:02:01 -0400134
Eric Parisff311002010-07-28 10:18:37 -0400135 if (fsn_mark->mask & IN_ONESHOT)
136 fsnotify_destroy_mark(fsn_mark);
137
Eric Paris63c882a2009-05-21 17:02:01 -0400138 /*
Eric Paris000285d2009-12-17 21:24:24 -0500139 * If we hold the fsn_mark until after the event is on the queue
Eric Paris63c882a2009-05-21 17:02:01 -0400140 * IN_IGNORED won't be able to pass this event in the queue
141 */
Eric Paris000285d2009-12-17 21:24:24 -0500142 fsnotify_put_mark(fsn_mark);
Eric Paris63c882a2009-05-21 17:02:01 -0400143
144 return ret;
145}
146
Eric Paris000285d2009-12-17 21:24:24 -0500147static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group)
Eric Paris63c882a2009-05-21 17:02:01 -0400148{
Eric Paris000285d2009-12-17 21:24:24 -0500149 inotify_ignored_and_remove_idr(fsn_mark, group);
Eric Paris63c882a2009-05-21 17:02:01 -0400150}
151
Eric Paris7b0a04f2009-12-17 21:24:21 -0500152static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode,
Eric Paris3a9b16b2010-07-28 10:18:38 -0400153 struct vfsmount *mnt, struct fsnotify_mark *mark,
154 __u32 mask, void *data, int data_type)
Eric Paris63c882a2009-05-21 17:02:01 -0400155{
Eric Paris000285d2009-12-17 21:24:24 -0500156 struct fsnotify_mark *fsn_mark;
Eric Paris63c882a2009-05-21 17:02:01 -0400157 bool send;
158
Eric Paris5ba08e22010-07-28 10:18:37 -0400159 pr_debug("%s: group=%p inode=%p mask=%x data=%p data_type=%d\n",
160 __func__, group, inode, mask, data, data_type);
161
Eric Paris5444e292009-12-17 21:24:27 -0500162 fsn_mark = fsnotify_find_inode_mark(group, inode);
Eric Paris000285d2009-12-17 21:24:24 -0500163 if (!fsn_mark)
Eric Paris63c882a2009-05-21 17:02:01 -0400164 return false;
165
Eric Parise42e2772009-06-11 11:09:47 -0400166 mask = (mask & ~FS_EVENT_ON_CHILD);
Eric Paris000285d2009-12-17 21:24:24 -0500167 send = (fsn_mark->mask & mask);
Eric Paris63c882a2009-05-21 17:02:01 -0400168
Eric Paris8c1934c2010-07-28 10:18:37 -0400169 if (send && (fsn_mark->mask & FS_EXCL_UNLINK) &&
Eric Paris3bcf3862010-07-28 10:18:37 -0400170 (data_type == FSNOTIFY_EVENT_FILE)) {
171 struct file *file = data;
Eric Paris8c1934c2010-07-28 10:18:37 -0400172
Eric Paris3bcf3862010-07-28 10:18:37 -0400173 if (d_unlinked(file->f_path.dentry))
Eric Paris8c1934c2010-07-28 10:18:37 -0400174 send = false;
175 }
176
Eric Paris63c882a2009-05-21 17:02:01 -0400177 /* find took a reference */
Eric Paris000285d2009-12-17 21:24:24 -0500178 fsnotify_put_mark(fsn_mark);
Eric Paris63c882a2009-05-21 17:02:01 -0400179
180 return send;
181}
182
Eric Pariscf437422009-08-24 16:03:35 -0400183/*
184 * This is NEVER supposed to be called. Inotify marks should either have been
185 * removed from the idr when the watch was removed or in the
186 * fsnotify_destroy_mark_by_group() call when the inotify instance was being
187 * torn down. This is only called if the idr is about to be freed but there
188 * are still marks in it.
189 */
Eric Paris63c882a2009-05-21 17:02:01 -0400190static int idr_callback(int id, void *p, void *data)
191{
Eric Paris000285d2009-12-17 21:24:24 -0500192 struct fsnotify_mark *fsn_mark;
193 struct inotify_inode_mark *i_mark;
Eric Pariscf437422009-08-24 16:03:35 -0400194 static bool warned = false;
195
196 if (warned)
197 return 0;
198
Eric Paris976ae322010-01-15 12:12:25 -0500199 warned = true;
Eric Paris000285d2009-12-17 21:24:24 -0500200 fsn_mark = p;
201 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
Eric Pariscf437422009-08-24 16:03:35 -0400202
Eric Paris000285d2009-12-17 21:24:24 -0500203 WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in "
Eric Pariscf437422009-08-24 16:03:35 -0400204 "idr. Probably leaking memory\n", id, p, data);
205
206 /*
207 * I'm taking the liberty of assuming that the mark in question is a
208 * valid address and I'm dereferencing it. This might help to figure
209 * out why we got here and the panic is no worse than the original
210 * BUG() that was here.
211 */
Eric Paris000285d2009-12-17 21:24:24 -0500212 if (fsn_mark)
213 printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n",
214 fsn_mark->group, fsn_mark->i.inode, i_mark->wd);
Eric Paris63c882a2009-05-21 17:02:01 -0400215 return 0;
216}
217
218static void inotify_free_group_priv(struct fsnotify_group *group)
219{
220 /* ideally the idr is empty and we won't hit the BUG in teh callback */
Eric Pariscf437422009-08-24 16:03:35 -0400221 idr_for_each(&group->inotify_data.idr, idr_callback, group);
Eric Paris63c882a2009-05-21 17:02:01 -0400222 idr_remove_all(&group->inotify_data.idr);
223 idr_destroy(&group->inotify_data.idr);
Pavel Emelyanovb3b38d82010-05-12 15:34:07 -0700224 free_uid(group->inotify_data.user);
Eric Paris63c882a2009-05-21 17:02:01 -0400225}
226
227void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv)
228{
229 struct inotify_event_private_data *event_priv;
230
231
232 event_priv = container_of(fsn_event_priv, struct inotify_event_private_data,
233 fsnotify_event_priv_data);
234
235 kmem_cache_free(event_priv_cachep, event_priv);
236}
237
238const struct fsnotify_ops inotify_fsnotify_ops = {
239 .handle_event = inotify_handle_event,
240 .should_send_event = inotify_should_send_event,
241 .free_group_priv = inotify_free_group_priv,
242 .free_event_priv = inotify_free_event_priv,
243 .freeing_mark = inotify_freeing_mark,
244};