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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 | /* EEXIST is not an error */ | |
66 | if (ret == -EEXIST) | |
67 | ret = 0; | |
68 | ||
69 | /* did event_priv get attached? */ | |
70 | if (list_empty(&fsn_event_priv->event_list)) | |
71 | inotify_free_event_priv(fsn_event_priv); | |
72 | ||
73 | /* | |
74 | * If we hold the entry until after the event is on the queue | |
75 | * IN_IGNORED won't be able to pass this event in the queue | |
76 | */ | |
77 | fsnotify_put_mark(entry); | |
78 | ||
79 | return ret; | |
80 | } | |
81 | ||
82 | static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) | |
83 | { | |
528da3e9 | 84 | inotify_ignored_and_remove_idr(entry, group); |
63c882a0 EP |
85 | } |
86 | ||
87 | static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) | |
88 | { | |
89 | struct fsnotify_mark_entry *entry; | |
90 | bool send; | |
91 | ||
92 | spin_lock(&inode->i_lock); | |
93 | entry = fsnotify_find_mark_entry(group, inode); | |
94 | spin_unlock(&inode->i_lock); | |
95 | if (!entry) | |
96 | return false; | |
97 | ||
e42e2773 | 98 | mask = (mask & ~FS_EVENT_ON_CHILD); |
63c882a0 EP |
99 | send = (entry->mask & mask); |
100 | ||
101 | /* find took a reference */ | |
102 | fsnotify_put_mark(entry); | |
103 | ||
104 | return send; | |
105 | } | |
106 | ||
107 | static int idr_callback(int id, void *p, void *data) | |
108 | { | |
109 | BUG(); | |
110 | return 0; | |
111 | } | |
112 | ||
113 | static void inotify_free_group_priv(struct fsnotify_group *group) | |
114 | { | |
115 | /* ideally the idr is empty and we won't hit the BUG in teh callback */ | |
116 | idr_for_each(&group->inotify_data.idr, idr_callback, NULL); | |
117 | idr_remove_all(&group->inotify_data.idr); | |
118 | idr_destroy(&group->inotify_data.idr); | |
119 | } | |
120 | ||
121 | void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) | |
122 | { | |
123 | struct inotify_event_private_data *event_priv; | |
124 | ||
125 | ||
126 | event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, | |
127 | fsnotify_event_priv_data); | |
128 | ||
129 | kmem_cache_free(event_priv_cachep, event_priv); | |
130 | } | |
131 | ||
132 | const struct fsnotify_ops inotify_fsnotify_ops = { | |
133 | .handle_event = inotify_handle_event, | |
134 | .should_send_event = inotify_should_send_event, | |
135 | .free_group_priv = inotify_free_group_priv, | |
136 | .free_event_priv = inotify_free_event_priv, | |
137 | .freeing_mark = inotify_freeing_mark, | |
138 | }; |