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 /* run all of the dentries associated with this inode. Since this is a
64 * directory, there damn well better only be one item on this list */
65 list_for_each_entry(alias, &inode->i_dentry, d_alias) {
68 /* run all of the children of the original inode and fix their
69 * d_flags to indicate parental interest (their parent is the
71 list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
75 spin_lock(&child->d_lock);
77 child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
79 child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
80 spin_unlock(&child->d_lock);
83 spin_unlock(&dcache_lock);
86 /* Notify this dentry's parent about a child's events. */
87 void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
89 struct dentry *parent;
90 struct inode *p_inode;
92 bool should_update_children = false;
95 dentry = file->f_path.dentry;
97 if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
100 spin_lock(&dentry->d_lock);
101 parent = dentry->d_parent;
102 p_inode = parent->d_inode;
104 if (fsnotify_inode_watches_children(p_inode)) {
105 if (p_inode->i_fsnotify_mask & mask) {
111 * The parent doesn't care about events on it's children but
112 * at least one child thought it did. We need to run all the
113 * children and update their d_flags to let them know p_inode
114 * doesn't care about them any more.
117 should_update_children = true;
120 spin_unlock(&dentry->d_lock);
123 /* we are notifying a parent so come up with the new mask which
124 * specifies these are events which came from a child. */
125 mask |= FS_EVENT_ON_CHILD;
128 fsnotify(p_inode, mask, file, FSNOTIFY_EVENT_FILE,
129 dentry->d_name.name, 0);
131 fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
132 dentry->d_name.name, 0);
136 if (unlikely(should_update_children)) {
137 __fsnotify_update_child_dentry_flags(p_inode);
141 EXPORT_SYMBOL_GPL(__fsnotify_parent);
143 static int send_to_group(struct inode *to_tell, struct vfsmount *mnt,
144 struct fsnotify_mark *mark,
145 __u32 mask, void *data,
146 int data_is, u32 cookie,
147 const unsigned char *file_name,
148 struct fsnotify_event **event)
150 struct fsnotify_group *group = mark->group;
151 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
153 pr_debug("%s: group=%p to_tell=%p mnt=%p mark=%p mask=%x data=%p"
154 " data_is=%d cookie=%d event=%p\n", __func__, group, to_tell,
155 mnt, mark, mask, data, data_is, cookie, *event);
157 if ((mask & FS_MODIFY) &&
158 !(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
159 mark->ignored_mask = 0;
161 if (!(test_mask & mark->mask & ~mark->ignored_mask))
164 if (group->ops->should_send_event(group, to_tell, mnt, mark, mask,
165 data, data_is) == false)
169 *event = fsnotify_create_event(to_tell, mask, data,
175 return group->ops->handle_event(group, mark, *event);
179 * This is the main call to fsnotify. The VFS calls into hook specific functions
180 * in linux/fsnotify.h. Those functions then in turn call here. Here will call
181 * out to all of the registered fsnotify_group. Those groups can then use the
182 * notification event in whatever means they feel necessary.
184 int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
185 const unsigned char *file_name, u32 cookie)
187 struct hlist_node *inode_node, *vfsmount_node;
188 struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL;
189 struct fsnotify_group *inode_group, *vfsmount_group;
190 struct fsnotify_event *event = NULL;
191 struct vfsmount *mnt;
193 bool used_inode = false, used_vfsmount = false;
194 /* global tests shouldn't care about events on child only the specific event */
195 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
197 if (data_is == FSNOTIFY_EVENT_FILE)
198 mnt = ((struct file *)data)->f_path.mnt;
203 * if this is a modify event we may need to clear the ignored masks
204 * otherwise return if neither the inode nor the vfsmount care about
205 * this type of event.
207 if (!(mask & FS_MODIFY) &&
208 !(test_mask & to_tell->i_fsnotify_mask) &&
209 !(mnt && test_mask & mnt->mnt_fsnotify_mask))
212 idx = srcu_read_lock(&fsnotify_mark_srcu);
214 if ((mask & FS_MODIFY) ||
215 (test_mask & to_tell->i_fsnotify_mask))
216 inode_node = to_tell->i_fsnotify_marks.first;
221 if ((mask & FS_MODIFY) ||
222 (test_mask & mnt->mnt_fsnotify_mask))
223 vfsmount_node = mnt->mnt_fsnotify_marks.first;
225 vfsmount_node = NULL;
228 vfsmount_node = NULL;
231 while (inode_node || vfsmount_node) {
233 inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu),
234 struct fsnotify_mark, i.i_list);
235 inode_group = inode_mark->group;
237 inode_group = (void *)-1;
240 vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu),
241 struct fsnotify_mark, m.m_list);
242 vfsmount_group = vfsmount_mark->group;
244 vfsmount_group = (void *)-1;
246 if (inode_group < vfsmount_group) {
248 send_to_group(to_tell, NULL, inode_mark, mask, data,
249 data_is, cookie, file_name, &event);
251 } else if (vfsmount_group < inode_group) {
252 send_to_group(to_tell, mnt, vfsmount_mark, mask, data,
253 data_is, cookie, file_name, &event);
254 used_vfsmount = true;
256 send_to_group(to_tell, mnt, vfsmount_mark, mask, data,
257 data_is, cookie, file_name, &event);
258 used_vfsmount = true;
259 send_to_group(to_tell, NULL, inode_mark, mask, data,
260 data_is, cookie, file_name, &event);
265 inode_node = inode_node->next;
267 vfsmount_node = vfsmount_node->next;
270 srcu_read_unlock(&fsnotify_mark_srcu, idx);
272 * fsnotify_create_event() took a reference so the event can't be cleaned
273 * up while we are still trying to add it to lists, drop that one.
276 fsnotify_put_event(event);
280 EXPORT_SYMBOL_GPL(fsnotify);
282 static __init int fsnotify_init(void)
286 BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
288 ret = init_srcu_struct(&fsnotify_mark_srcu);
290 panic("initializing fsnotify_mark_srcu");
294 core_initcall(fsnotify_init);