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Eric Paris90586522009-05-21 17:01:20 -04001/*
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/dcache.h>
20#include <linux/fs.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/gfp.h>
Eric Paris90586522009-05-21 17:01:20 -040022#include <linux/init.h>
23#include <linux/module.h>
Eric Paris71314852009-12-17 21:24:23 -050024#include <linux/mount.h>
Eric Paris90586522009-05-21 17:01:20 -040025#include <linux/srcu.h>
26
27#include <linux/fsnotify_backend.h>
28#include "fsnotify.h"
Al Viroc63181e2011-11-25 02:35:16 -050029#include "../mount.h"
Eric Paris90586522009-05-21 17:01:20 -040030
31/*
Eric Paris3be25f42009-05-21 17:01:26 -040032 * Clear all of the marks on an inode when it is being evicted from core
33 */
34void __fsnotify_inode_delete(struct inode *inode)
35{
36 fsnotify_clear_marks_by_inode(inode);
37}
38EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
39
Andreas Gruenbacherca9c7262009-12-17 21:24:27 -050040void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
41{
42 fsnotify_clear_marks_by_mount(mnt);
43}
44
Eric Paris3be25f42009-05-21 17:01:26 -040045/*
Eric Parisc28f7e52009-05-21 17:01:29 -040046 * Given an inode, first check if we care what happens to our children. Inotify
47 * and dnotify both tell their parents about events. If we care about any event
48 * on a child we run all of our children and set a dentry flag saying that the
49 * parent cares. Thus when an event happens on a child it can quickly tell if
50 * if there is a need to find a parent and send the event to the parent.
51 */
52void __fsnotify_update_child_dentry_flags(struct inode *inode)
53{
54 struct dentry *alias;
55 int watched;
56
57 if (!S_ISDIR(inode->i_mode))
58 return;
59
60 /* determine if the children should tell inode about their events */
61 watched = fsnotify_inode_watches_children(inode);
62
Nick Piggin873feea2011-01-07 17:50:06 +110063 spin_lock(&inode->i_lock);
Eric Parisc28f7e52009-05-21 17:01:29 -040064 /* run all of the dentries associated with this inode. Since this is a
65 * directory, there damn well better only be one item on this list */
66 list_for_each_entry(alias, &inode->i_dentry, d_alias) {
67 struct dentry *child;
68
69 /* run all of the children of the original inode and fix their
70 * d_flags to indicate parental interest (their parent is the
71 * original inode) */
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110072 spin_lock(&alias->d_lock);
Eric Parisc28f7e52009-05-21 17:01:29 -040073 list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
74 if (!child->d_inode)
75 continue;
76
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110077 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
Eric Parisc28f7e52009-05-21 17:01:29 -040078 if (watched)
79 child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
80 else
81 child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
82 spin_unlock(&child->d_lock);
83 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110084 spin_unlock(&alias->d_lock);
Eric Parisc28f7e52009-05-21 17:01:29 -040085 }
Nick Piggin873feea2011-01-07 17:50:06 +110086 spin_unlock(&inode->i_lock);
Eric Parisc28f7e52009-05-21 17:01:29 -040087}
88
89/* Notify this dentry's parent about a child's events. */
Eric Paris52420392010-10-28 17:21:56 -040090int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
Eric Parisc28f7e52009-05-21 17:01:29 -040091{
92 struct dentry *parent;
93 struct inode *p_inode;
Eric Paris52420392010-10-28 17:21:56 -040094 int ret = 0;
Eric Parisc28f7e52009-05-21 17:01:29 -040095
Andreas Gruenbacher72acc852009-12-17 21:24:24 -050096 if (!dentry)
Linus Torvalds20696012010-08-12 14:23:04 -070097 dentry = path->dentry;
Eric Paris28c60e32009-12-17 21:24:21 -050098
Eric Parisc28f7e52009-05-21 17:01:29 -040099 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
Eric Paris52420392010-10-28 17:21:56 -0400100 return 0;
Eric Parisc28f7e52009-05-21 17:01:29 -0400101
Christoph Hellwig4d4eb362010-10-10 05:36:30 -0400102 parent = dget_parent(dentry);
Eric Parisc28f7e52009-05-21 17:01:29 -0400103 p_inode = parent->d_inode;
104
Christoph Hellwig4d4eb362010-10-10 05:36:30 -0400105 if (unlikely(!fsnotify_inode_watches_children(p_inode)))
106 __fsnotify_update_child_dentry_flags(p_inode);
107 else if (p_inode->i_fsnotify_mask & mask) {
Eric Parisc28f7e52009-05-21 17:01:29 -0400108 /* we are notifying a parent so come up with the new mask which
109 * specifies these are events which came from a child. */
110 mask |= FS_EVENT_ON_CHILD;
111
Linus Torvalds20696012010-08-12 14:23:04 -0700112 if (path)
Eric Paris52420392010-10-28 17:21:56 -0400113 ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
114 dentry->d_name.name, 0);
Eric Paris28c60e32009-12-17 21:24:21 -0500115 else
Eric Paris52420392010-10-28 17:21:56 -0400116 ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
117 dentry->d_name.name, 0);
Eric Parisc28f7e52009-05-21 17:01:29 -0400118 }
119
Christoph Hellwig4d4eb362010-10-10 05:36:30 -0400120 dput(parent);
Eric Paris52420392010-10-28 17:21:56 -0400121
122 return ret;
Eric Parisc28f7e52009-05-21 17:01:29 -0400123}
124EXPORT_SYMBOL_GPL(__fsnotify_parent);
125
Eric Paris613a8072010-07-28 10:18:39 -0400126static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
Eric Parisce8f76f2010-07-28 10:18:39 -0400127 struct fsnotify_mark *inode_mark,
128 struct fsnotify_mark *vfsmount_mark,
129 __u32 mask, void *data,
Eric Paris613a8072010-07-28 10:18:39 -0400130 int data_is, u32 cookie,
Eric Paris3a9b16b2010-07-28 10:18:38 -0400131 const unsigned char *file_name,
Eric Parisc4ec54b2009-12-17 21:24:34 -0500132 struct fsnotify_event **event)
Eric Paris71314852009-12-17 21:24:23 -0500133{
Eric Parisfaa95602010-08-18 12:25:49 -0400134 struct fsnotify_group *group = NULL;
Eric Paris84e1ab42010-08-18 12:25:50 -0400135 __u32 inode_test_mask = 0;
136 __u32 vfsmount_test_mask = 0;
Eric Paris613a8072010-07-28 10:18:39 -0400137
Eric Parisfaa95602010-08-18 12:25:49 -0400138 if (unlikely(!inode_mark && !vfsmount_mark)) {
139 BUG();
140 return 0;
141 }
Eric Paris5ba08e22010-07-28 10:18:37 -0400142
Eric Parisce8f76f2010-07-28 10:18:39 -0400143 /* clear ignored on inode modification */
144 if (mask & FS_MODIFY) {
145 if (inode_mark &&
146 !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
147 inode_mark->ignored_mask = 0;
148 if (vfsmount_mark &&
149 !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
150 vfsmount_mark->ignored_mask = 0;
151 }
Eric Paris613a8072010-07-28 10:18:39 -0400152
Eric Parisce8f76f2010-07-28 10:18:39 -0400153 /* does the inode mark tell us to do something? */
154 if (inode_mark) {
Eric Parisfaa95602010-08-18 12:25:49 -0400155 group = inode_mark->group;
Eric Paris84e1ab42010-08-18 12:25:50 -0400156 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
Eric Parisce8f76f2010-07-28 10:18:39 -0400157 inode_test_mask &= inode_mark->mask;
158 inode_test_mask &= ~inode_mark->ignored_mask;
159 }
160
161 /* does the vfsmount_mark tell us to do something? */
162 if (vfsmount_mark) {
Eric Paris84e1ab42010-08-18 12:25:50 -0400163 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
Eric Parisfaa95602010-08-18 12:25:49 -0400164 group = vfsmount_mark->group;
Eric Parisce8f76f2010-07-28 10:18:39 -0400165 vfsmount_test_mask &= vfsmount_mark->mask;
166 vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
167 if (inode_mark)
168 vfsmount_test_mask &= ~inode_mark->ignored_mask;
169 }
170
Eric Paris84e1ab42010-08-18 12:25:50 -0400171 pr_debug("%s: group=%p to_tell=%p mnt=%p mask=%x inode_mark=%p"
172 " inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
173 " data=%p data_is=%d cookie=%d event=%p\n",
174 __func__, group, to_tell, mnt, mask, inode_mark,
175 inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
176 data_is, cookie, *event);
Eric Parisfaa95602010-08-18 12:25:49 -0400177
Eric Parisce8f76f2010-07-28 10:18:39 -0400178 if (!inode_test_mask && !vfsmount_test_mask)
Eric Paris613a8072010-07-28 10:18:39 -0400179 return 0;
180
Eric Paris1968f5e2010-07-28 10:18:39 -0400181 if (group->ops->should_send_event(group, to_tell, inode_mark,
Eric Parisce8f76f2010-07-28 10:18:39 -0400182 vfsmount_mark, mask, data,
183 data_is) == false)
Eric Parisc4ec54b2009-12-17 21:24:34 -0500184 return 0;
Eric Paris613a8072010-07-28 10:18:39 -0400185
Eric Paris71314852009-12-17 21:24:23 -0500186 if (!*event) {
187 *event = fsnotify_create_event(to_tell, mask, data,
188 data_is, file_name,
189 cookie, GFP_KERNEL);
Eric Paris71314852009-12-17 21:24:23 -0500190 if (!*event)
Eric Parisc4ec54b2009-12-17 21:24:34 -0500191 return -ENOMEM;
Eric Paris71314852009-12-17 21:24:23 -0500192 }
Eric Parisce8f76f2010-07-28 10:18:39 -0400193 return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event);
Eric Paris71314852009-12-17 21:24:23 -0500194}
195
Eric Parisc28f7e52009-05-21 17:01:29 -0400196/*
Eric Paris90586522009-05-21 17:01:20 -0400197 * This is the main call to fsnotify. The VFS calls into hook specific functions
198 * in linux/fsnotify.h. Those functions then in turn call here. Here will call
199 * out to all of the registered fsnotify_group. Those groups can then use the
200 * notification event in whatever means they feel necessary.
201 */
Eric Parisc4ec54b2009-12-17 21:24:34 -0500202int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
203 const unsigned char *file_name, u32 cookie)
Eric Paris90586522009-05-21 17:01:20 -0400204{
Eric Paris84e1ab42010-08-18 12:25:50 -0400205 struct hlist_node *inode_node = NULL, *vfsmount_node = NULL;
Eric Paris613a8072010-07-28 10:18:39 -0400206 struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
207 struct fsnotify_group *inode_group, *vfsmount_group;
Eric Paris90586522009-05-21 17:01:20 -0400208 struct fsnotify_event *event = NULL;
Al Viroc63181e2011-11-25 02:35:16 -0500209 struct mount *mnt;
Eric Parisc4ec54b2009-12-17 21:24:34 -0500210 int idx, ret = 0;
Eric Parise42e2772009-06-11 11:09:47 -0400211 /* global tests shouldn't care about events on child only the specific event */
212 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
Eric Paris90586522009-05-21 17:01:20 -0400213
Linus Torvalds20696012010-08-12 14:23:04 -0700214 if (data_is == FSNOTIFY_EVENT_PATH)
Al Viroc63181e2011-11-25 02:35:16 -0500215 mnt = real_mount(((struct path *)data)->mnt);
Eric Paris613a8072010-07-28 10:18:39 -0400216 else
217 mnt = NULL;
218
219 /*
220 * if this is a modify event we may need to clear the ignored masks
221 * otherwise return if neither the inode nor the vfsmount care about
222 * this type of event.
223 */
224 if (!(mask & FS_MODIFY) &&
225 !(test_mask & to_tell->i_fsnotify_mask) &&
226 !(mnt && test_mask & mnt->mnt_fsnotify_mask))
227 return 0;
Eric Paris3a9fb892009-12-17 21:24:23 -0500228
Eric Paris75c1be42010-07-28 10:18:38 -0400229 idx = srcu_read_lock(&fsnotify_mark_srcu);
Eric Paris71314852009-12-17 21:24:23 -0500230
Eric Paris613a8072010-07-28 10:18:39 -0400231 if ((mask & FS_MODIFY) ||
232 (test_mask & to_tell->i_fsnotify_mask))
Eric Parisce8f76f2010-07-28 10:18:39 -0400233 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
234 &fsnotify_mark_srcu);
Eric Paris75c1be42010-07-28 10:18:38 -0400235
Eric Paris84e1ab42010-08-18 12:25:50 -0400236 if (mnt && ((mask & FS_MODIFY) ||
237 (test_mask & mnt->mnt_fsnotify_mask))) {
238 vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
239 &fsnotify_mark_srcu);
240 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
241 &fsnotify_mark_srcu);
Eric Paris90586522009-05-21 17:01:20 -0400242 }
Eric Paris75c1be42010-07-28 10:18:38 -0400243
Eric Paris613a8072010-07-28 10:18:39 -0400244 while (inode_node || vfsmount_node) {
Eric Parisf72adfd2010-08-27 21:24:24 -0400245 inode_group = vfsmount_group = NULL;
Eric Paris5f3f2592010-08-18 12:25:49 -0400246
Eric Paris613a8072010-07-28 10:18:39 -0400247 if (inode_node) {
248 inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
249 struct fsnotify_mark, i.i_list);
250 inode_group = inode_mark->group;
Eric Parisf72adfd2010-08-27 21:24:24 -0400251 }
Eric Paris75c1be42010-07-28 10:18:38 -0400252
Eric Paris613a8072010-07-28 10:18:39 -0400253 if (vfsmount_node) {
254 vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
255 struct fsnotify_mark, m.m_list);
256 vfsmount_group = vfsmount_mark->group;
Eric Parisf72adfd2010-08-27 21:24:24 -0400257 }
Eric Paris75c1be42010-07-28 10:18:38 -0400258
Eric Parisf72adfd2010-08-27 21:24:24 -0400259 if (inode_group > vfsmount_group) {
Eric Paris613a8072010-07-28 10:18:39 -0400260 /* handle inode */
Eric Parisff8bcbd2010-10-28 17:21:56 -0400261 ret = send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
262 data_is, cookie, file_name, &event);
Eric Paris92b46782010-08-27 21:42:11 -0400263 /* we didn't use the vfsmount_mark */
264 vfsmount_group = NULL;
Eric Parisf72adfd2010-08-27 21:24:24 -0400265 } else if (vfsmount_group > inode_group) {
Al Viroc63181e2011-11-25 02:35:16 -0500266 ret = send_to_group(to_tell, &mnt->mnt, NULL, vfsmount_mark, mask, data,
Eric Parisff8bcbd2010-10-28 17:21:56 -0400267 data_is, cookie, file_name, &event);
Eric Paris92b46782010-08-27 21:42:11 -0400268 inode_group = NULL;
Eric Paris613a8072010-07-28 10:18:39 -0400269 } else {
Al Viroc63181e2011-11-25 02:35:16 -0500270 ret = send_to_group(to_tell, &mnt->mnt, inode_mark, vfsmount_mark,
Eric Parisff8bcbd2010-10-28 17:21:56 -0400271 mask, data, data_is, cookie, file_name,
272 &event);
Eric Paris71314852009-12-17 21:24:23 -0500273 }
Eric Paris613a8072010-07-28 10:18:39 -0400274
Eric Parisff8bcbd2010-10-28 17:21:56 -0400275 if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
276 goto out;
277
Eric Paris92b46782010-08-27 21:42:11 -0400278 if (inode_group)
Eric Parisce8f76f2010-07-28 10:18:39 -0400279 inode_node = srcu_dereference(inode_node->next,
280 &fsnotify_mark_srcu);
Eric Paris92b46782010-08-27 21:42:11 -0400281 if (vfsmount_group)
Eric Parisce8f76f2010-07-28 10:18:39 -0400282 vfsmount_node = srcu_dereference(vfsmount_node->next,
283 &fsnotify_mark_srcu);
Eric Paris71314852009-12-17 21:24:23 -0500284 }
Eric Parisff8bcbd2010-10-28 17:21:56 -0400285 ret = 0;
286out:
Eric Paris75c1be42010-07-28 10:18:38 -0400287 srcu_read_unlock(&fsnotify_mark_srcu, idx);
Eric Paris90586522009-05-21 17:01:20 -0400288 /*
289 * fsnotify_create_event() took a reference so the event can't be cleaned
290 * up while we are still trying to add it to lists, drop that one.
291 */
292 if (event)
293 fsnotify_put_event(event);
Eric Parisc4ec54b2009-12-17 21:24:34 -0500294
Jean-Christophe Dubois98b5c102010-03-23 08:08:09 +0100295 return ret;
Eric Paris90586522009-05-21 17:01:20 -0400296}
297EXPORT_SYMBOL_GPL(fsnotify);
298
299static __init int fsnotify_init(void)
300{
Eric Paris75c1be42010-07-28 10:18:38 -0400301 int ret;
302
Eric Paris20dee622010-07-28 10:18:37 -0400303 BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
304
Eric Paris75c1be42010-07-28 10:18:38 -0400305 ret = init_srcu_struct(&fsnotify_mark_srcu);
306 if (ret)
307 panic("initializing fsnotify_mark_srcu");
308
309 return 0;
Eric Paris90586522009-05-21 17:01:20 -0400310}
Eric Paris75c1be42010-07-28 10:18:38 -0400311core_initcall(fsnotify_init);