2 * fs/inotify_user.c - inotify support for userspace
5 * John McCutchan <ttb@tentacle.dhs.org>
6 * Robert Love <rml@novell.com>
8 * Copyright (C) 2005 John McCutchan
9 * Copyright 2006 Hewlett-Packard Development Company, L.P.
11 * Copyright (C) 2009 Eric Paris <Red Hat Inc>
12 * inotify was largely rewriten to make use of the fsnotify infrastructure
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
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.
25 #include <linux/dcache.h> /* d_unlinked */
26 #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>
32 #include <linux/sched.h>
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.
40 static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new)
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 */
52 !strcmp(old->file_name, new->file_name))
55 case (FSNOTIFY_EVENT_PATH):
56 if ((old->path.mnt == new->path.mnt) &&
57 (old->path.dentry == new->path.dentry))
60 case (FSNOTIFY_EVENT_NONE):
61 if (old->mask & FS_Q_OVERFLOW)
63 else if (old->mask & FS_IN_IGNORED)
71 static int inotify_merge(struct list_head *list,
72 struct fsnotify_event *event,
75 struct fsnotify_event_holder *last_holder;
76 struct fsnotify_event *last_event;
79 /* and the list better be locked by something too */
80 spin_lock(&event->lock);
82 last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list);
83 last_event = last_holder->event;
84 if (event_compare(last_event, event))
87 spin_unlock(&event->lock);
92 static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
94 struct fsnotify_mark *fsn_mark;
95 struct inotify_inode_mark *i_mark;
96 struct inode *to_tell;
97 struct inotify_event_private_data *event_priv;
98 struct fsnotify_event_private_data *fsn_event_priv;
101 to_tell = event->to_tell;
103 fsn_mark = fsnotify_find_inode_mark(group, to_tell);
104 /* race with watch removal? We already passes should_send */
105 if (unlikely(!fsn_mark))
107 i_mark = container_of(fsn_mark, struct inotify_inode_mark,
111 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL);
112 if (unlikely(!event_priv))
115 fsn_event_priv = &event_priv->fsnotify_event_priv_data;
117 fsn_event_priv->group = group;
120 ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge, NULL);
122 inotify_free_event_priv(fsn_event_priv);
123 /* EEXIST says we tail matched, EOVERFLOW isn't something
124 * to report up the stack. */
125 if ((ret == -EEXIST) ||
130 if (fsn_mark->mask & IN_ONESHOT)
131 fsnotify_destroy_mark(fsn_mark);
134 * If we hold the fsn_mark until after the event is on the queue
135 * IN_IGNORED won't be able to pass this event in the queue
137 fsnotify_put_mark(fsn_mark);
142 static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group)
144 inotify_ignored_and_remove_idr(fsn_mark, group);
147 static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode,
148 struct vfsmount *mnt, __u32 mask, void *data,
151 struct fsnotify_mark *fsn_mark;
154 fsn_mark = fsnotify_find_inode_mark(group, inode);
158 mask = (mask & ~FS_EVENT_ON_CHILD);
159 send = (fsn_mark->mask & mask);
161 if (send && (fsn_mark->mask & FS_EXCL_UNLINK) &&
162 (data_type == FSNOTIFY_EVENT_PATH)) {
163 struct path *path = data;
165 if (d_unlinked(path->dentry))
169 /* find took a reference */
170 fsnotify_put_mark(fsn_mark);
176 * This is NEVER supposed to be called. Inotify marks should either have been
177 * removed from the idr when the watch was removed or in the
178 * fsnotify_destroy_mark_by_group() call when the inotify instance was being
179 * torn down. This is only called if the idr is about to be freed but there
180 * are still marks in it.
182 static int idr_callback(int id, void *p, void *data)
184 struct fsnotify_mark *fsn_mark;
185 struct inotify_inode_mark *i_mark;
186 static bool warned = false;
193 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
195 WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in "
196 "idr. Probably leaking memory\n", id, p, data);
199 * I'm taking the liberty of assuming that the mark in question is a
200 * valid address and I'm dereferencing it. This might help to figure
201 * out why we got here and the panic is no worse than the original
202 * BUG() that was here.
205 printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n",
206 fsn_mark->group, fsn_mark->i.inode, i_mark->wd);
210 static void inotify_free_group_priv(struct fsnotify_group *group)
212 /* ideally the idr is empty and we won't hit the BUG in teh callback */
213 idr_for_each(&group->inotify_data.idr, idr_callback, group);
214 idr_remove_all(&group->inotify_data.idr);
215 idr_destroy(&group->inotify_data.idr);
216 free_uid(group->inotify_data.user);
219 void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv)
221 struct inotify_event_private_data *event_priv;
224 event_priv = container_of(fsn_event_priv, struct inotify_event_private_data,
225 fsnotify_event_priv_data);
227 kmem_cache_free(event_priv_cachep, event_priv);
230 const struct fsnotify_ops inotify_fsnotify_ops = {
231 .handle_event = inotify_handle_event,
232 .should_send_event = inotify_should_send_event,
233 .free_group_priv = inotify_free_group_priv,
234 .free_event_priv = inotify_free_event_priv,
235 .freeing_mark = inotify_freeing_mark,