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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 | ||
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 | ||
32 | #include "inotify.h" | |
33 | ||
34 | static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) | |
35 | { | |
36 | struct fsnotify_mark_entry *entry; | |
37 | struct inotify_inode_mark_entry *ientry; | |
38 | struct inode *to_tell; | |
39 | struct inotify_event_private_data *event_priv; | |
40 | struct fsnotify_event_private_data *fsn_event_priv; | |
41 | int wd, ret; | |
42 | ||
43 | to_tell = event->to_tell; | |
44 | ||
45 | spin_lock(&to_tell->i_lock); | |
46 | entry = fsnotify_find_mark_entry(group, to_tell); | |
47 | spin_unlock(&to_tell->i_lock); | |
48 | /* race with watch removal? We already passes should_send */ | |
49 | if (unlikely(!entry)) | |
50 | return 0; | |
51 | ientry = container_of(entry, struct inotify_inode_mark_entry, | |
52 | fsn_entry); | |
53 | wd = ientry->wd; | |
54 | ||
55 | event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); | |
56 | if (unlikely(!event_priv)) | |
57 | return -ENOMEM; | |
58 | ||
59 | fsn_event_priv = &event_priv->fsnotify_event_priv_data; | |
60 | ||
61 | fsn_event_priv->group = group; | |
62 | event_priv->wd = wd; | |
63 | ||
64 | ret = fsnotify_add_notify_event(group, event, fsn_event_priv); | |
eef3a116 | 65 | if (ret) { |
63c882a0 | 66 | inotify_free_event_priv(fsn_event_priv); |
eef3a116 EP |
67 | /* EEXIST says we tail matched, EOVERFLOW isn't something |
68 | * to report up the stack. */ | |
69 | if ((ret == -EEXIST) || | |
70 | (ret == -EOVERFLOW)) | |
71 | ret = 0; | |
72 | } | |
63c882a0 EP |
73 | |
74 | /* | |
75 | * If we hold the entry until after the event is on the queue | |
76 | * IN_IGNORED won't be able to pass this event in the queue | |
77 | */ | |
78 | fsnotify_put_mark(entry); | |
79 | ||
80 | return ret; | |
81 | } | |
82 | ||
83 | static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) | |
84 | { | |
528da3e9 | 85 | inotify_ignored_and_remove_idr(entry, group); |
63c882a0 EP |
86 | } |
87 | ||
88 | static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) | |
89 | { | |
90 | struct fsnotify_mark_entry *entry; | |
91 | bool send; | |
92 | ||
93 | spin_lock(&inode->i_lock); | |
94 | entry = fsnotify_find_mark_entry(group, inode); | |
95 | spin_unlock(&inode->i_lock); | |
96 | if (!entry) | |
97 | return false; | |
98 | ||
e42e2773 | 99 | mask = (mask & ~FS_EVENT_ON_CHILD); |
63c882a0 EP |
100 | send = (entry->mask & mask); |
101 | ||
102 | /* find took a reference */ | |
103 | fsnotify_put_mark(entry); | |
104 | ||
105 | return send; | |
106 | } | |
107 | ||
cf437426 EP |
108 | /* |
109 | * This is NEVER supposed to be called. Inotify marks should either have been | |
110 | * removed from the idr when the watch was removed or in the | |
111 | * fsnotify_destroy_mark_by_group() call when the inotify instance was being | |
112 | * torn down. This is only called if the idr is about to be freed but there | |
113 | * are still marks in it. | |
114 | */ | |
63c882a0 EP |
115 | static int idr_callback(int id, void *p, void *data) |
116 | { | |
cf437426 EP |
117 | struct fsnotify_mark_entry *entry; |
118 | struct inotify_inode_mark_entry *ientry; | |
119 | static bool warned = false; | |
120 | ||
121 | if (warned) | |
122 | return 0; | |
123 | ||
976ae32b | 124 | warned = true; |
cf437426 EP |
125 | entry = p; |
126 | ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); | |
127 | ||
128 | WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in " | |
129 | "idr. Probably leaking memory\n", id, p, data); | |
130 | ||
131 | /* | |
132 | * I'm taking the liberty of assuming that the mark in question is a | |
133 | * valid address and I'm dereferencing it. This might help to figure | |
134 | * out why we got here and the panic is no worse than the original | |
135 | * BUG() that was here. | |
136 | */ | |
137 | if (entry) | |
138 | printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n", | |
139 | entry->group, entry->inode, ientry->wd); | |
63c882a0 EP |
140 | return 0; |
141 | } | |
142 | ||
143 | static void inotify_free_group_priv(struct fsnotify_group *group) | |
144 | { | |
145 | /* ideally the idr is empty and we won't hit the BUG in teh callback */ | |
cf437426 | 146 | idr_for_each(&group->inotify_data.idr, idr_callback, group); |
63c882a0 EP |
147 | idr_remove_all(&group->inotify_data.idr); |
148 | idr_destroy(&group->inotify_data.idr); | |
149 | } | |
150 | ||
151 | void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) | |
152 | { | |
153 | struct inotify_event_private_data *event_priv; | |
154 | ||
155 | ||
156 | event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, | |
157 | fsnotify_event_priv_data); | |
158 | ||
159 | kmem_cache_free(event_priv_cachep, event_priv); | |
160 | } | |
161 | ||
162 | const struct fsnotify_ops inotify_fsnotify_ops = { | |
163 | .handle_event = inotify_handle_event, | |
164 | .should_send_event = inotify_should_send_event, | |
165 | .free_group_priv = inotify_free_group_priv, | |
166 | .free_event_priv = inotify_free_event_priv, | |
167 | .freeing_mark = inotify_freeing_mark, | |
168 | }; |