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0d48b7f0 EP |
1 | /* |
2 | * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2, or (at your option) | |
7 | * any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; see the file COPYING. If not, write to | |
16 | * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
17 | */ | |
18 | ||
19 | #include <linux/fs.h> | |
20 | #include <linux/init.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/mount.h> | |
24 | #include <linux/mutex.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/spinlock.h> | |
27 | #include <linux/writeback.h> /* for inode_lock */ | |
28 | ||
29 | #include <asm/atomic.h> | |
30 | ||
31 | #include <linux/fsnotify_backend.h> | |
32 | #include "fsnotify.h" | |
33 | ||
34 | void fsnotify_clear_marks_by_mount(struct vfsmount *mnt) | |
35 | { | |
36 | struct fsnotify_mark *mark, *lmark; | |
37 | struct hlist_node *pos, *n; | |
38 | LIST_HEAD(free_list); | |
39 | ||
40 | spin_lock(&mnt->mnt_root->d_lock); | |
41 | hlist_for_each_entry_safe(mark, pos, n, &mnt->mnt_fsnotify_marks, m.m_list) { | |
42 | list_add(&mark->m.free_m_list, &free_list); | |
43 | hlist_del_init(&mark->m.m_list); | |
44 | fsnotify_get_mark(mark); | |
45 | } | |
46 | spin_unlock(&mnt->mnt_root->d_lock); | |
47 | ||
48 | list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) { | |
49 | fsnotify_destroy_mark(mark); | |
50 | fsnotify_put_mark(mark); | |
51 | } | |
52 | } | |
53 | ||
54 | /* | |
55 | * Recalculate the mask of events relevant to a given vfsmount locked. | |
56 | */ | |
57 | static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt) | |
58 | { | |
59 | struct fsnotify_mark *mark; | |
60 | struct hlist_node *pos; | |
61 | __u32 new_mask = 0; | |
62 | ||
63 | assert_spin_locked(&mnt->mnt_root->d_lock); | |
64 | ||
65 | hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) | |
66 | new_mask |= mark->mask; | |
67 | mnt->mnt_fsnotify_mask = new_mask; | |
68 | } | |
69 | ||
70 | /* | |
71 | * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types | |
72 | * any notifier is interested in hearing for this mount point | |
73 | */ | |
74 | void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt) | |
75 | { | |
76 | spin_lock(&mnt->mnt_root->d_lock); | |
77 | fsnotify_recalc_vfsmount_mask_locked(mnt); | |
78 | spin_unlock(&mnt->mnt_root->d_lock); | |
79 | } | |
80 | ||
81 | void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark) | |
82 | { | |
83 | struct vfsmount *mnt = mark->m.mnt; | |
84 | ||
85 | assert_spin_locked(&mark->lock); | |
86 | assert_spin_locked(&mark->group->mark_lock); | |
87 | ||
88 | spin_lock(&mnt->mnt_root->d_lock); | |
89 | ||
90 | hlist_del_init(&mark->m.m_list); | |
91 | mark->m.mnt = NULL; | |
92 | ||
93 | fsnotify_recalc_vfsmount_mask_locked(mnt); | |
94 | ||
95 | spin_unlock(&mnt->mnt_root->d_lock); | |
96 | } | |
97 | ||
98 | static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group, | |
99 | struct vfsmount *mnt) | |
100 | { | |
101 | struct fsnotify_mark *mark; | |
102 | struct hlist_node *pos; | |
103 | ||
104 | assert_spin_locked(&mnt->mnt_root->d_lock); | |
105 | ||
106 | hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) { | |
107 | if (mark->group == group) { | |
108 | fsnotify_get_mark(mark); | |
109 | return mark; | |
110 | } | |
111 | } | |
112 | return NULL; | |
113 | } | |
114 | ||
115 | /* | |
116 | * given a group and vfsmount, find the mark associated with that combination. | |
117 | * if found take a reference to that mark and return it, else return NULL | |
118 | */ | |
119 | struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, | |
120 | struct vfsmount *mnt) | |
121 | { | |
122 | struct fsnotify_mark *mark; | |
123 | ||
124 | spin_lock(&mnt->mnt_root->d_lock); | |
125 | mark = fsnotify_find_vfsmount_mark_locked(group, mnt); | |
126 | spin_unlock(&mnt->mnt_root->d_lock); | |
127 | ||
128 | return mark; | |
129 | } | |
130 | ||
131 | /* | |
132 | * Attach an initialized mark to a given group and vfsmount. | |
133 | * These marks may be used for the fsnotify backend to determine which | |
134 | * event types should be delivered to which groups. | |
135 | */ | |
136 | int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, | |
137 | struct fsnotify_group *group, struct vfsmount *mnt, | |
138 | int allow_dups) | |
139 | { | |
140 | struct fsnotify_mark *lmark = NULL; | |
141 | int ret = 0; | |
142 | ||
143 | mark->flags = FSNOTIFY_MARK_FLAG_VFSMOUNT; | |
144 | ||
145 | /* | |
146 | * LOCKING ORDER!!!! | |
147 | * mark->lock | |
148 | * group->mark_lock | |
149 | * mnt->mnt_root->d_lock | |
150 | */ | |
151 | assert_spin_locked(&mark->lock); | |
152 | assert_spin_locked(&group->mark_lock); | |
153 | ||
154 | spin_lock(&mnt->mnt_root->d_lock); | |
155 | ||
156 | if (!allow_dups) | |
157 | lmark = fsnotify_find_vfsmount_mark_locked(group, mnt); | |
158 | if (!lmark) { | |
159 | mark->m.mnt = mnt; | |
160 | ||
161 | hlist_add_head(&mark->m.m_list, &mnt->mnt_fsnotify_marks); | |
162 | ||
163 | fsnotify_recalc_vfsmount_mask_locked(mnt); | |
164 | } else { | |
165 | ret = -EEXIST; | |
166 | } | |
167 | ||
168 | spin_unlock(&mnt->mnt_root->d_lock); | |
169 | ||
170 | return ret; | |
171 | } |