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/fs.h> /* struct inode */
26 #include <linux/fsnotify_backend.h>
27 #include <linux/inotify.h>
28 #include <linux/path.h> /* struct path */
29 #include <linux/slab.h> /* kmem_* */
30 #include <linux/types.h>
31 #include <linux/sched.h>
36 * Check if 2 events contain the same information. We do not compare private data
37 * but at this moment that isn't a problem for any know fsnotify listeners.
39 static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new)
41 if ((old->mask == new->mask) &&
42 (old->to_tell == new->to_tell) &&
43 (old->data_type == new->data_type) &&
44 (old->name_len == new->name_len)) {
45 switch (old->data_type) {
46 case (FSNOTIFY_EVENT_INODE):
47 /* remember, after old was put on the wait_q we aren't
48 * allowed to look at the inode any more, only thing
49 * left to check was if the file_name is the same */
51 !strcmp(old->file_name, new->file_name))
54 case (FSNOTIFY_EVENT_PATH):
55 if ((old->path.mnt == new->path.mnt) &&
56 (old->path.dentry == new->path.dentry))
59 case (FSNOTIFY_EVENT_NONE):
60 if (old->mask & FS_Q_OVERFLOW)
62 else if (old->mask & FS_IN_IGNORED)
70 static int inotify_merge(struct list_head *list, struct fsnotify_event *event)
72 struct fsnotify_event_holder *last_holder;
73 struct fsnotify_event *last_event;
76 /* and the list better be locked by something too */
77 spin_lock(&event->lock);
79 last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list);
80 last_event = last_holder->event;
81 if (event_compare(last_event, event))
84 spin_unlock(&event->lock);
89 static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
91 struct fsnotify_mark *entry;
92 struct inotify_inode_mark_entry *ientry;
93 struct inode *to_tell;
94 struct inotify_event_private_data *event_priv;
95 struct fsnotify_event_private_data *fsn_event_priv;
98 to_tell = event->to_tell;
100 spin_lock(&to_tell->i_lock);
101 entry = fsnotify_find_mark(group, to_tell);
102 spin_unlock(&to_tell->i_lock);
103 /* race with watch removal? We already passes should_send */
104 if (unlikely(!entry))
106 ientry = container_of(entry, struct inotify_inode_mark_entry,
110 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL);
111 if (unlikely(!event_priv))
114 fsn_event_priv = &event_priv->fsnotify_event_priv_data;
116 fsn_event_priv->group = group;
119 ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge);
121 inotify_free_event_priv(fsn_event_priv);
122 /* EEXIST says we tail matched, EOVERFLOW isn't something
123 * to report up the stack. */
124 if ((ret == -EEXIST) ||
130 * If we hold the entry until after the event is on the queue
131 * IN_IGNORED won't be able to pass this event in the queue
133 fsnotify_put_mark(entry);
138 static void inotify_freeing_mark(struct fsnotify_mark *entry, struct fsnotify_group *group)
140 inotify_ignored_and_remove_idr(entry, group);
143 static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode,
144 struct vfsmount *mnt, __u32 mask, void *data,
147 struct fsnotify_mark *entry;
150 spin_lock(&inode->i_lock);
151 entry = fsnotify_find_mark(group, inode);
152 spin_unlock(&inode->i_lock);
156 mask = (mask & ~FS_EVENT_ON_CHILD);
157 send = (entry->mask & mask);
159 /* find took a reference */
160 fsnotify_put_mark(entry);
166 * This is NEVER supposed to be called. Inotify marks should either have been
167 * removed from the idr when the watch was removed or in the
168 * fsnotify_destroy_mark_by_group() call when the inotify instance was being
169 * torn down. This is only called if the idr is about to be freed but there
170 * are still marks in it.
172 static int idr_callback(int id, void *p, void *data)
174 struct fsnotify_mark *entry;
175 struct inotify_inode_mark_entry *ientry;
176 static bool warned = false;
183 ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
185 WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in "
186 "idr. Probably leaking memory\n", id, p, data);
189 * I'm taking the liberty of assuming that the mark in question is a
190 * valid address and I'm dereferencing it. This might help to figure
191 * out why we got here and the panic is no worse than the original
192 * BUG() that was here.
195 printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n",
196 entry->group, entry->i.inode, ientry->wd);
200 static void inotify_free_group_priv(struct fsnotify_group *group)
202 /* ideally the idr is empty and we won't hit the BUG in teh callback */
203 idr_for_each(&group->inotify_data.idr, idr_callback, group);
204 idr_remove_all(&group->inotify_data.idr);
205 idr_destroy(&group->inotify_data.idr);
206 free_uid(group->inotify_data.user);
209 void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv)
211 struct inotify_event_private_data *event_priv;
214 event_priv = container_of(fsn_event_priv, struct inotify_event_private_data,
215 fsnotify_event_priv_data);
217 kmem_cache_free(event_priv_cachep, event_priv);
220 const struct fsnotify_ops inotify_fsnotify_ops = {
221 .handle_event = inotify_handle_event,
222 .should_send_event = inotify_should_send_event,
223 .free_group_priv = inotify_free_group_priv,
224 .free_event_priv = inotify_free_event_priv,
225 .freeing_mark = inotify_freeing_mark,