2 * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
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)
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.
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.
19 #include <linux/dcache.h>
21 #include <linux/gfp.h>
22 #include <linux/init.h>
23 #include <linux/module.h>
24 #include <linux/mount.h>
25 #include <linux/srcu.h>
27 #include <linux/fsnotify_backend.h>
31 * Clear all of the marks on an inode when it is being evicted from core
33 void __fsnotify_inode_delete(struct inode *inode)
35 fsnotify_clear_marks_by_inode(inode);
37 EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
39 void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
41 fsnotify_clear_marks_by_mount(mnt);
45 * Given an inode, first check if we care what happens to our children. Inotify
46 * and dnotify both tell their parents about events. If we care about any event
47 * on a child we run all of our children and set a dentry flag saying that the
48 * parent cares. Thus when an event happens on a child it can quickly tell if
49 * if there is a need to find a parent and send the event to the parent.
51 void __fsnotify_update_child_dentry_flags(struct inode *inode)
56 if (!S_ISDIR(inode->i_mode))
59 /* determine if the children should tell inode about their events */
60 watched = fsnotify_inode_watches_children(inode);
62 spin_lock(&dcache_lock);
63 spin_lock(&dcache_inode_lock);
64 /* 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) {
69 /* run all of the children of the original inode and fix their
70 * d_flags to indicate parental interest (their parent is the
72 spin_lock(&alias->d_lock);
73 list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
77 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
79 child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
81 child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
82 spin_unlock(&child->d_lock);
84 spin_unlock(&alias->d_lock);
86 spin_unlock(&dcache_inode_lock);
87 spin_unlock(&dcache_lock);
90 /* Notify this dentry's parent about a child's events. */
91 int __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
93 struct dentry *parent;
94 struct inode *p_inode;
98 dentry = path->dentry;
100 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
103 parent = dget_parent(dentry);
104 p_inode = parent->d_inode;
106 if (unlikely(!fsnotify_inode_watches_children(p_inode)))
107 __fsnotify_update_child_dentry_flags(p_inode);
108 else if (p_inode->i_fsnotify_mask & mask) {
109 /* we are notifying a parent so come up with the new mask which
110 * specifies these are events which came from a child. */
111 mask |= FS_EVENT_ON_CHILD;
114 ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
115 dentry->d_name.name, 0);
117 ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
118 dentry->d_name.name, 0);
125 EXPORT_SYMBOL_GPL(__fsnotify_parent);
127 static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
128 struct fsnotify_mark *inode_mark,
129 struct fsnotify_mark *vfsmount_mark,
130 __u32 mask, void *data,
131 int data_is, u32 cookie,
132 const unsigned char *file_name,
133 struct fsnotify_event **event)
135 struct fsnotify_group *group = NULL;
136 __u32 inode_test_mask = 0;
137 __u32 vfsmount_test_mask = 0;
139 if (unlikely(!inode_mark && !vfsmount_mark)) {
144 /* clear ignored on inode modification */
145 if (mask & FS_MODIFY) {
147 !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
148 inode_mark->ignored_mask = 0;
150 !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
151 vfsmount_mark->ignored_mask = 0;
154 /* does the inode mark tell us to do something? */
156 group = inode_mark->group;
157 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD);
158 inode_test_mask &= inode_mark->mask;
159 inode_test_mask &= ~inode_mark->ignored_mask;
162 /* does the vfsmount_mark tell us to do something? */
164 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD);
165 group = vfsmount_mark->group;
166 vfsmount_test_mask &= vfsmount_mark->mask;
167 vfsmount_test_mask &= ~vfsmount_mark->ignored_mask;
169 vfsmount_test_mask &= ~inode_mark->ignored_mask;
172 pr_debug("%s: group=%p to_tell=%p mnt=%p mask=%x inode_mark=%p"
173 " inode_test_mask=%x vfsmount_mark=%p vfsmount_test_mask=%x"
174 " data=%p data_is=%d cookie=%d event=%p\n",
175 __func__, group, to_tell, mnt, mask, inode_mark,
176 inode_test_mask, vfsmount_mark, vfsmount_test_mask, data,
177 data_is, cookie, *event);
179 if (!inode_test_mask && !vfsmount_test_mask)
182 if (group->ops->should_send_event(group, to_tell, inode_mark,
183 vfsmount_mark, mask, data,
188 *event = fsnotify_create_event(to_tell, mask, data,
194 return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event);
198 * This is the main call to fsnotify. The VFS calls into hook specific functions
199 * in linux/fsnotify.h. Those functions then in turn call here. Here will call
200 * out to all of the registered fsnotify_group. Those groups can then use the
201 * notification event in whatever means they feel necessary.
203 int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
204 const unsigned char *file_name, u32 cookie)
206 struct hlist_node *inode_node = NULL, *vfsmount_node = NULL;
207 struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
208 struct fsnotify_group *inode_group, *vfsmount_group;
209 struct fsnotify_event *event = NULL;
210 struct vfsmount *mnt;
212 /* global tests shouldn't care about events on child only the specific event */
213 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
215 if (data_is == FSNOTIFY_EVENT_PATH)
216 mnt = ((struct path *)data)->mnt;
221 * if this is a modify event we may need to clear the ignored masks
222 * otherwise return if neither the inode nor the vfsmount care about
223 * this type of event.
225 if (!(mask & FS_MODIFY) &&
226 !(test_mask & to_tell->i_fsnotify_mask) &&
227 !(mnt && test_mask & mnt->mnt_fsnotify_mask))
230 idx = srcu_read_lock(&fsnotify_mark_srcu);
232 if ((mask & FS_MODIFY) ||
233 (test_mask & to_tell->i_fsnotify_mask))
234 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
235 &fsnotify_mark_srcu);
237 if (mnt && ((mask & FS_MODIFY) ||
238 (test_mask & mnt->mnt_fsnotify_mask))) {
239 vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first,
240 &fsnotify_mark_srcu);
241 inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first,
242 &fsnotify_mark_srcu);
245 while (inode_node || vfsmount_node) {
246 inode_group = vfsmount_group = NULL;
249 inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
250 struct fsnotify_mark, i.i_list);
251 inode_group = inode_mark->group;
255 vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
256 struct fsnotify_mark, m.m_list);
257 vfsmount_group = vfsmount_mark->group;
260 if (inode_group > vfsmount_group) {
262 ret = send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
263 data_is, cookie, file_name, &event);
264 /* we didn't use the vfsmount_mark */
265 vfsmount_group = NULL;
266 } else if (vfsmount_group > inode_group) {
267 ret = send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
268 data_is, cookie, file_name, &event);
271 ret = send_to_group(to_tell, mnt, inode_mark, vfsmount_mark,
272 mask, data, data_is, cookie, file_name,
276 if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
280 inode_node = srcu_dereference(inode_node->next,
281 &fsnotify_mark_srcu);
283 vfsmount_node = srcu_dereference(vfsmount_node->next,
284 &fsnotify_mark_srcu);
288 srcu_read_unlock(&fsnotify_mark_srcu, idx);
290 * fsnotify_create_event() took a reference so the event can't be cleaned
291 * up while we are still trying to add it to lists, drop that one.
294 fsnotify_put_event(event);
298 EXPORT_SYMBOL_GPL(fsnotify);
300 static __init int fsnotify_init(void)
304 BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
306 ret = init_srcu_struct(&fsnotify_mark_srcu);
308 panic("initializing fsnotify_mark_srcu");
312 core_initcall(fsnotify_init);