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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); |
65 | if (ret) { |
66 | inotify_free_event_priv(fsn_event_priv); |
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 | } |
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 | { |
85 | inotify_ignored_and_remove_idr(entry, group); |
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 | |
99 | mask = (mask & ~FS_EVENT_ON_CHILD); |
100 | send = (entry->mask & mask); |
101 | |
102 | /* find took a reference */ |
103 | fsnotify_put_mark(entry); |
104 | |
105 | return send; |
106 | } |
107 | |
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 | */ |
115 | static int idr_callback(int id, void *p, void *data) |
116 | { |
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 | |
124 | warned = true; |
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); |
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 */ |
146 | idr_for_each(&group->inotify_data.idr, idr_callback, group); |
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 | }; |
169 |
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