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63c882a0 EP |
1 | /* |
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 | ||
8c1934c8 | 25 | #include <linux/dcache.h> /* d_unlinked */ |
63c882a0 EP |
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> | |
b3b38d84 | 32 | #include <linux/sched.h> |
63c882a0 EP |
33 | |
34 | #include "inotify.h" | |
35 | ||
74766bbf EP |
36 | /* |
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 | */ | |
40 | static 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; | |
55 | case (FSNOTIFY_EVENT_PATH): | |
56 | if ((old->path.mnt == new->path.mnt) && | |
57 | (old->path.dentry == new->path.dentry)) | |
58 | 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 | ||
6e5f77b3 EP |
71 | static int inotify_merge(struct list_head *list, |
72 | struct fsnotify_event *event, | |
73 | void **arg) | |
74766bbf EP |
74 | { |
75 | struct fsnotify_event_holder *last_holder; | |
76 | struct fsnotify_event *last_event; | |
77 | int ret = 0; | |
78 | ||
79 | /* and the list better be locked by something too */ | |
80 | spin_lock(&event->lock); | |
81 | ||
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)) | |
85 | ret = -EEXIST; | |
86 | ||
87 | spin_unlock(&event->lock); | |
88 | ||
89 | return ret; | |
90 | } | |
91 | ||
63c882a0 EP |
92 | static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) |
93 | { | |
000285de EP |
94 | struct fsnotify_mark *fsn_mark; |
95 | struct inotify_inode_mark *i_mark; | |
63c882a0 EP |
96 | struct inode *to_tell; |
97 | struct inotify_event_private_data *event_priv; | |
98 | struct fsnotify_event_private_data *fsn_event_priv; | |
99 | int wd, ret; | |
100 | ||
5ba08e2e EP |
101 | pr_debug("%s: group=%p event=%p to_tell=%p mask=%x\n", __func__, group, |
102 | event, event->to_tell, event->mask); | |
103 | ||
63c882a0 EP |
104 | to_tell = event->to_tell; |
105 | ||
5444e298 | 106 | fsn_mark = fsnotify_find_inode_mark(group, to_tell); |
63c882a0 | 107 | /* race with watch removal? We already passes should_send */ |
000285de | 108 | if (unlikely(!fsn_mark)) |
63c882a0 | 109 | return 0; |
000285de EP |
110 | i_mark = container_of(fsn_mark, struct inotify_inode_mark, |
111 | fsn_mark); | |
112 | wd = i_mark->wd; | |
63c882a0 EP |
113 | |
114 | event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); | |
115 | if (unlikely(!event_priv)) | |
116 | return -ENOMEM; | |
117 | ||
118 | fsn_event_priv = &event_priv->fsnotify_event_priv_data; | |
119 | ||
120 | fsn_event_priv->group = group; | |
121 | event_priv->wd = wd; | |
122 | ||
6e5f77b3 | 123 | ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge, NULL); |
eef3a116 | 124 | if (ret) { |
63c882a0 | 125 | inotify_free_event_priv(fsn_event_priv); |
eef3a116 EP |
126 | /* EEXIST says we tail matched, EOVERFLOW isn't something |
127 | * to report up the stack. */ | |
128 | if ((ret == -EEXIST) || | |
129 | (ret == -EOVERFLOW)) | |
130 | ret = 0; | |
131 | } | |
63c882a0 | 132 | |
ff311008 EP |
133 | if (fsn_mark->mask & IN_ONESHOT) |
134 | fsnotify_destroy_mark(fsn_mark); | |
135 | ||
63c882a0 | 136 | /* |
000285de | 137 | * If we hold the fsn_mark until after the event is on the queue |
63c882a0 EP |
138 | * IN_IGNORED won't be able to pass this event in the queue |
139 | */ | |
000285de | 140 | fsnotify_put_mark(fsn_mark); |
63c882a0 EP |
141 | |
142 | return ret; | |
143 | } | |
144 | ||
000285de | 145 | static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) |
63c882a0 | 146 | { |
000285de | 147 | inotify_ignored_and_remove_idr(fsn_mark, group); |
63c882a0 EP |
148 | } |
149 | ||
7b0a04fb | 150 | static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, |
3a9fb89f EP |
151 | struct vfsmount *mnt, __u32 mask, void *data, |
152 | int data_type) | |
63c882a0 | 153 | { |
000285de | 154 | struct fsnotify_mark *fsn_mark; |
63c882a0 EP |
155 | bool send; |
156 | ||
5ba08e2e EP |
157 | pr_debug("%s: group=%p inode=%p mask=%x data=%p data_type=%d\n", |
158 | __func__, group, inode, mask, data, data_type); | |
159 | ||
5444e298 | 160 | fsn_mark = fsnotify_find_inode_mark(group, inode); |
000285de | 161 | if (!fsn_mark) |
63c882a0 EP |
162 | return false; |
163 | ||
e42e2773 | 164 | mask = (mask & ~FS_EVENT_ON_CHILD); |
000285de | 165 | send = (fsn_mark->mask & mask); |
63c882a0 | 166 | |
8c1934c8 EP |
167 | if (send && (fsn_mark->mask & FS_EXCL_UNLINK) && |
168 | (data_type == FSNOTIFY_EVENT_PATH)) { | |
169 | struct path *path = data; | |
170 | ||
171 | if (d_unlinked(path->dentry)) | |
172 | send = false; | |
173 | } | |
174 | ||
63c882a0 | 175 | /* find took a reference */ |
000285de | 176 | fsnotify_put_mark(fsn_mark); |
63c882a0 EP |
177 | |
178 | return send; | |
179 | } | |
180 | ||
cf437426 EP |
181 | /* |
182 | * This is NEVER supposed to be called. Inotify marks should either have been | |
183 | * removed from the idr when the watch was removed or in the | |
184 | * fsnotify_destroy_mark_by_group() call when the inotify instance was being | |
185 | * torn down. This is only called if the idr is about to be freed but there | |
186 | * are still marks in it. | |
187 | */ | |
63c882a0 EP |
188 | static int idr_callback(int id, void *p, void *data) |
189 | { | |
000285de EP |
190 | struct fsnotify_mark *fsn_mark; |
191 | struct inotify_inode_mark *i_mark; | |
cf437426 EP |
192 | static bool warned = false; |
193 | ||
194 | if (warned) | |
195 | return 0; | |
196 | ||
976ae32b | 197 | warned = true; |
000285de EP |
198 | fsn_mark = p; |
199 | i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); | |
cf437426 | 200 | |
000285de | 201 | WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in " |
cf437426 EP |
202 | "idr. Probably leaking memory\n", id, p, data); |
203 | ||
204 | /* | |
205 | * I'm taking the liberty of assuming that the mark in question is a | |
206 | * valid address and I'm dereferencing it. This might help to figure | |
207 | * out why we got here and the panic is no worse than the original | |
208 | * BUG() that was here. | |
209 | */ | |
000285de EP |
210 | if (fsn_mark) |
211 | printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n", | |
212 | fsn_mark->group, fsn_mark->i.inode, i_mark->wd); | |
63c882a0 EP |
213 | return 0; |
214 | } | |
215 | ||
216 | static void inotify_free_group_priv(struct fsnotify_group *group) | |
217 | { | |
218 | /* ideally the idr is empty and we won't hit the BUG in teh callback */ | |
cf437426 | 219 | idr_for_each(&group->inotify_data.idr, idr_callback, group); |
63c882a0 EP |
220 | idr_remove_all(&group->inotify_data.idr); |
221 | idr_destroy(&group->inotify_data.idr); | |
b3b38d84 | 222 | free_uid(group->inotify_data.user); |
63c882a0 EP |
223 | } |
224 | ||
225 | void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) | |
226 | { | |
227 | struct inotify_event_private_data *event_priv; | |
228 | ||
229 | ||
230 | event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, | |
231 | fsnotify_event_priv_data); | |
232 | ||
233 | kmem_cache_free(event_priv_cachep, event_priv); | |
234 | } | |
235 | ||
236 | const struct fsnotify_ops inotify_fsnotify_ops = { | |
237 | .handle_event = inotify_handle_event, | |
238 | .should_send_event = inotify_should_send_event, | |
239 | .free_group_priv = inotify_free_group_priv, | |
240 | .free_event_priv = inotify_free_event_priv, | |
241 | .freeing_mark = inotify_freeing_mark, | |
242 | }; |