2 * Directory notifications for Linux.
4 * Copyright (C) 2000,2001,2002 Stephen Rothwell
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2, or (at your option) any
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
17 #include <linux/module.h>
18 #include <linux/sched.h>
19 #include <linux/dnotify.h>
20 #include <linux/init.h>
21 #include <linux/spinlock.h>
22 #include <linux/slab.h>
24 int dir_notify_enable = 1;
26 static rwlock_t dn_lock = RW_LOCK_UNLOCKED;
27 static kmem_cache_t *dn_cache;
29 static void redo_inode_mask(struct inode *inode)
31 unsigned long new_mask;
32 struct dnotify_struct *dn;
35 for (dn = inode->i_dnotify; dn != NULL; dn = dn->dn_next)
36 new_mask |= dn->dn_mask & ~DN_MULTISHOT;
37 inode->i_dnotify_mask = new_mask;
40 void dnotify_flush(struct file *filp, fl_owner_t id)
42 struct dnotify_struct *dn;
43 struct dnotify_struct **prev;
46 inode = filp->f_dentry->d_inode;
47 if (!S_ISDIR(inode->i_mode))
50 prev = &inode->i_dnotify;
51 while ((dn = *prev) != NULL) {
52 if ((dn->dn_owner == id) && (dn->dn_filp == filp)) {
54 redo_inode_mask(inode);
55 kmem_cache_free(dn_cache, dn);
60 write_unlock(&dn_lock);
63 int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
65 struct dnotify_struct *dn;
66 struct dnotify_struct *odn;
67 struct dnotify_struct **prev;
69 fl_owner_t id = current->files;
72 if ((arg & ~DN_MULTISHOT) == 0) {
73 dnotify_flush(filp, id);
76 if (!dir_notify_enable)
78 inode = filp->f_dentry->d_inode;
79 if (!S_ISDIR(inode->i_mode))
81 dn = kmem_cache_alloc(dn_cache, SLAB_KERNEL);
85 prev = &inode->i_dnotify;
86 while ((odn = *prev) != NULL) {
87 if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
90 inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
96 error = f_setown(filp, current->pid, 0);
104 inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
105 dn->dn_next = inode->i_dnotify;
106 inode->i_dnotify = dn;
108 write_unlock(&dn_lock);
111 kmem_cache_free(dn_cache, dn);
115 void __inode_dir_notify(struct inode *inode, unsigned long event)
117 struct dnotify_struct * dn;
118 struct dnotify_struct **prev;
119 struct fown_struct * fown;
122 write_lock(&dn_lock);
123 prev = &inode->i_dnotify;
124 while ((dn = *prev) != NULL) {
125 if ((dn->dn_mask & event) == 0) {
129 fown = &dn->dn_filp->f_owner;
130 send_sigio(fown, dn->dn_fd, POLL_MSG);
131 if (dn->dn_mask & DN_MULTISHOT)
136 kmem_cache_free(dn_cache, dn);
140 redo_inode_mask(inode);
141 write_unlock(&dn_lock);
144 EXPORT_SYMBOL(__inode_dir_notify);
147 * This is hopelessly wrong, but unfixable without API changes. At
148 * least it doesn't oops the kernel...
150 * To safely access ->d_parent we need to keep d_move away from it. Use the
151 * dentry's d_lock for this.
153 void dnotify_parent(struct dentry *dentry, unsigned long event)
155 struct dentry *parent;
157 if (!dir_notify_enable)
160 spin_lock(&dentry->d_lock);
161 parent = dentry->d_parent;
162 if (parent->d_inode->i_dnotify_mask & event) {
164 spin_unlock(&dentry->d_lock);
165 __inode_dir_notify(parent->d_inode, event);
168 spin_unlock(&dentry->d_lock);
171 EXPORT_SYMBOL_GPL(dnotify_parent);
173 static int __init dnotify_init(void)
175 dn_cache = kmem_cache_create("dnotify_cache",
176 sizeof(struct dnotify_struct), 0, SLAB_PANIC, NULL, NULL);
180 module_init(dnotify_init)