[RFC][PATCH] inotify 0.9.2

John McCutchan
2004-09-20T03:25:36Z

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Hello,

Here is release 0.9.2 of inotify. Attached is a patch to 2.6.8.1

--New in this version--
Works with 4K stack kernels
Stops timers properly when using SMP

A couple of things to note,

The memory usage analysis below is worst case, when inotify is watching
65536 inodes.
Inotify does pin inodes, but this is no different than dnotify.

Inotify is designed as a replacement for dnotify.
The key difference's are:

Inotify does not require the file to be opened to watch it
When a path you are watching is unmounted you will recieve an UNMOUNT
event.
Events are devilered over a FD that is select()-able not with signals.

--COMPLEXITY--

I have been asked what the complexity of inotify is. Inotify has
2 path codes where complexity could be an issue:

Adding a watcher to a device
This code has to check if the inode is already being watched
by the device, this is O(1) since the maximum number of
devices is limited to 8.

Removing a watch from a device
This code has to do a search of all watches on the device to
find the watch descriptor that is being asked to remove.
This involves a linear search, but should not really be an issue
because it is limited to 8192 entries. If this does turn in to
a concern, I would replace the list of watches on the device
with a sorted binary tree, so that the search could be done
very quickly.

The calls to inotify from the VFS code has a complexity of O(1) so
inotify does not affect the speed of VFS operations.

--MEMORY USAGE--

The inotify data structures are light weight:

inotify watch is 40 bytes
inotify device is 68 bytes
inotify event is 272 bytes

So assuming a device has 8192 watches, the structures are only going
to consume 320KB of memory. With a maximum number of 8 devices allowed
to exist at a time, this is still only 2.5 MB

Each device can also have 256 events queued at a time, which sums to
68KB per device. And only .5 MB if all devices are opened and have
a full event queue.

So approximately 3 MB of memory are used in the rare case of
everything open and full.

Each inotify watch pins the inode of a directory/file in memory,
the size of an inode is different per file system but lets assume
that it is 512 byes.

So assuming the maximum number of global watches are active, this would
pin down 32 MB of inodes in the inode cache. Again not a problem
on a modern system.

On smaller systems, the maximum watches / events could be lowered
to provide a smaller foot print.

Older release notes:
I am resubmitting inotify for comments and review. Inotify has
changed drastically from the earlier proposal that Al Viro did not
approve of. There is no longer any use of (device number, inode number)
pairs. Please give this version of inotify a fresh view.

Inotify is a character device that when opened offers 2 IOCTL's.
(It actually has 4 but the other 2 are used for debugging)

INOTIFY_WATCH:
Which takes a path and event mask and returns a unique
(to the instance of the driver) integer (wd [watch descriptor]
from here on) that is a 1:1 mapping to the path passed.
What happens is inotify gets the inode (and ref's the inode)
for the path and adds a inotify_watcher structure to the inodes
list of watchers. If this instance of the driver is already
watching the path, the event mask will be updated and
the original wd will be returned.

INOTIFY_IGNORE:
Which takes an integer (that you got from INOTIFY_WATCH)
representing a wd that you are not interested in watching
anymore. This will:

send an IGNORE event to the device
remove the inotify_watcher structure from the device and
from the inode and unref the inode.

After you are watching 1 or more paths, you can read from the fd
and get events. The events are struct inotify_event. If you are
watching a directory and something happens to a file in the directory
the event will contain the filename (just the filename not the full
path).

Aside from the inotify character device driver.
The changes to the kernel are very minor.

The first change is adding calls to inotify_inode_queue_event and
inotify_dentry_parent_queue_event from the various vfs functions. This
is identical to dnotify.

The second change is more serious, it adds a call to
inotify_super_block_umount
inside generic_shutdown_superblock. What inotify_super_block_umount does
is:

find all of the inodes that are on the super block being shut down,
sends each watcher on each inode the UNMOUNT and IGNORED event
removes the watcher structures from each instance of the device driver
and each inode.
unref's the inode.

I would appreciate design review, code review and testing.

John

[-- Attachment #2: inotify-0.9.2.diff --]
[-- Type: text/x-patch, Size: 36591 bytes --]

diff -urN linux-2.6.8.1/drivers/char/inotify.c ../linux/drivers/char/inotify.c
--- linux-2.6.8.1/drivers/char/inotify.c 1969-12-31 19:00:00.000000000 -0500
+++ ../linux/drivers/char/inotify.c 2004-09-18 03:03:15.000000000 -0400
@@ -0,0 +1,977 @@
+/*
+ * Inode based directory notifications for Linux.
+ *
+ * Copyright (C) 2004 John McCutchan
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * Signed-off-by: John McCutchan ttb@tentacle.dhs.org
+ */
+
+/* TODO:
+ * use rb tree so looking up watcher by watcher descriptor is faster.
+ * dev->watch_count is incremented twice for each watcher
+ */
+
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/miscdevice.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/writeback.h>
+#include <linux/inotify.h>
+
+#define MAX_INOTIFY_DEVS 8 /* We only support X watchers */
+#define MAX_INOTIFY_DEV_WATCHERS 8192 /* A dev can only have Y watchers */
+#define MAX_INOTIFY_QUEUED_EVENTS 256 /* Only the first Z events will be queued */
+#define __BITMASK_SIZE (MAX_INOTIFY_DEV_WATCHERS / 8)
+
+#define INOTIFY_DEV_TIMER_TIME jiffies + (HZ/4)
+
+static atomic_t watcher_count; // < MAX_INOTIFY_DEVS
+
+static kmem_cache_t *watcher_cache;
+static kmem_cache_t *kevent_cache;
+
+/* For debugging */
+static int event_object_count;
+static int watcher_object_count;
+static int inode_ref_count;
+static int inotify_debug_flags;
+#define iprintk(f, str...) if (inotify_debug_flags & f) printk (KERN_ALERT str)
+
+/* For each inotify device we need to keep a list of events queued on it,
+ * a list of inodes that we are watching and other stuff.
+ */
+struct inotify_device {
+ struct list_head events;
+ atomic_t event_count;
+ struct list_head watchers;
+ int watcher_count;
+ wait_queue_head_t wait;
+ struct timer_list timer;
+ char read_state;
+ spinlock_t lock;
+ void * bitmask;
+};
+#define inotify_device_event_list(pos) list_entry((pos), struct inotify_event, list)
+
+struct inotify_watcher {
+ int wd; // watcher descriptor
+ unsigned long mask;
+ struct inode * inode;
+ struct inotify_device * dev;
+ struct list_head d_list; // device list
+ struct list_head i_list; // inode list
+ struct list_head u_list; // unmount list
+};
+#define inotify_watcher_d_list(pos) list_entry((pos), struct inotify_watcher, d_list)
+#define inotify_watcher_i_list(pos) list_entry((pos), struct inotify_watcher, i_list)
+#define inotify_watcher_u_list(pos) list_entry((pos), struct inotify_watcher, u_list)
+
+/* A list of these is attached to each instance of the driver
+ * when the drivers read() gets called, this list is walked and
+ * all events that can fit in the buffer get delivered
+ */
+struct inotify_kernel_event {
+ struct list_head list;
+ struct inotify_event event;
+};
+#define list_to_inotify_kernel_event(pos) list_entry((pos), struct inotify_kernel_event, list)
+
+static int find_inode (const char __user *dirname, struct inode **inode)
+{
+ struct nameidata nd;
+ int error;
+
+ error = __user_walk (dirname, LOOKUP_FOLLOW, &nd);
+ if (error) {
+ iprintk(INOTIFY_DEBUG_INODE, "could not find inode\n");
+ goto out;
+ }
+
+ *inode = nd.dentry->d_inode;
+ __iget (*inode);
+ iprintk(INOTIFY_DEBUG_INODE, "ref'd inode\n");
+ inode_ref_count++;
+ path_release(&nd);
+out:
+ return error;
+}
+
+static void unref_inode (struct inode *inode) {
+ inode_ref_count--;
+ iprintk(INOTIFY_DEBUG_INODE, "unref'd inode\n");
+ iput (inode);
+}
+
+struct inotify_kernel_event *kernel_event (int wd, int mask, const char *filename) {
+ struct inotify_kernel_event *kevent;
+
+ kevent = kmem_cache_alloc (kevent_cache, GFP_ATOMIC);
+
+
+ if (!kevent) {
+ iprintk(INOTIFY_DEBUG_ALLOC, "failed to alloc kevent (%d,%d)\n", wd, mask);
+ goto out;
+ }
+
+ iprintk(INOTIFY_DEBUG_ALLOC, "alloced kevent %p (%d,%d)\n", kevent, wd, mask);
+
+ kevent->event.wd = wd;
+ kevent->event.mask = mask;
+ INIT_LIST_HEAD(&kevent->list);
+
+ if (filename) {
+ iprintk(INOTIFY_DEBUG_FILEN, "filename for event was %p %s\n", filename, filename);
+ strncpy (kevent->event.filename, filename, 256);
+ kevent->event.filename[255] = '\0';
+ iprintk(INOTIFY_DEBUG_FILEN, "filename after copying %s\n", kevent->event.filename);
+ } else {
+ iprintk(INOTIFY_DEBUG_FILEN, "no filename for event\n");
+ kevent->event.filename[0] = '\0';
+ }
+
+ event_object_count++;
+
+out:
+ return kevent;
+}
+
+void delete_kernel_event (struct inotify_kernel_event *kevent) {
+ if (!kevent) return;
+
+ event_object_count--;
+
+ INIT_LIST_HEAD(&kevent->list);
+ kevent->event.wd = -1;
+ kevent->event.mask = 0;
+
+ iprintk(INOTIFY_DEBUG_ALLOC, "free'd kevent %p\n", kevent);
+ kmem_cache_free (kevent_cache, kevent);
+}
+
+#define inotify_dev_has_events(dev) (!list_empty(&dev->events))
+#define inotify_dev_get_event(dev) (list_to_inotify_kernel_event(dev->events.next))
+/* Does this events mask get sent to the watcher ? */
+#define event_and(event_mask,watchers_mask) ((event_mask == IN_UNMOUNT) || \
+ (event_mask == IN_IGNORED) || \
+ (event_mask & watchers_mask))
+
+
+/* dev->lock == locked before calling */
+static void inotify_dev_queue_event (struct inotify_device *dev, struct inotify_watcher *watcher, int mask, const char *filename) {
+ struct inotify_kernel_event *kevent;
+
+ if (atomic_read(&dev->event_count) == MAX_INOTIFY_QUEUED_EVENTS) {
+ iprintk(INOTIFY_DEBUG_EVENTS, "event queue for %p overflowed\n", dev);
+ return;
+ }
+
+ if (!event_and(mask, watcher->inode->watchers_mask)||!event_and(mask, watcher->mask)) {
+ return;
+ }
+
+ atomic_inc(&dev->event_count);
+
+ kevent = kernel_event (watcher->wd, mask, filename);
+
+ if (!kevent) {
+ iprintk(INOTIFY_DEBUG_EVENTS, "failed to queue event %x for %p\n", mask, dev);
+ }
+
+ list_add_tail(&kevent->list, &dev->events);
+
+ iprintk(INOTIFY_DEBUG_EVENTS, "queued event %x for %p\n", mask, dev);
+}
+
+
+
+
+static void inotify_dev_event_dequeue (struct inotify_device *dev) {
+ struct inotify_kernel_event *kevent;
+
+ if (!inotify_dev_has_events (dev)) {
+ return;
+ }
+
+ kevent = inotify_dev_get_event(dev);
+
+ list_del(&kevent->list);
+ atomic_dec(&dev->event_count);
+
+ delete_kernel_event (kevent);
+
+ iprintk(INOTIFY_DEBUG_EVENTS, "dequeued event on %p\n", dev);
+}
+
+static int inotify_dev_get_wd (struct inotify_device *dev)
+{
+ int wd;
+
+ wd = -1;
+
+ if (!dev)
+ return -1;
+
+ if (dev->watcher_count == MAX_INOTIFY_DEV_WATCHERS) {
+ return -1;
+ }
+
+ dev->watcher_count++;
+
+ wd = find_first_zero_bit (dev->bitmask, __BITMASK_SIZE);
+
+ set_bit (wd, dev->bitmask);
+
+ return wd;
+}
+
+static int inotify_dev_put_wd (struct inotify_device *dev, int wd)
+{
+ if (!dev||wd < 0)
+ return -1;
+
+ dev->watcher_count--;
+
+ clear_bit (wd, dev->bitmask);
+
+ return 0;
+}
+
+
+static struct inotify_watcher *create_watcher (struct inotify_device *dev, int mask, struct inode *inode) {
+ struct inotify_watcher *watcher;
+
+ watcher = kmem_cache_alloc (watcher_cache, GFP_KERNEL);
+
+ if (!watcher) {
+ iprintk(INOTIFY_DEBUG_ALLOC, "failed to allocate watcher (%p,%d)\n", inode, mask);
+ return NULL;
+ }
+
+ watcher->wd = -1;
+ watcher->mask = mask;
+ watcher->inode = inode;
+ watcher->dev = dev;
+ INIT_LIST_HEAD(&watcher->d_list);
+ INIT_LIST_HEAD(&watcher->i_list);
+ INIT_LIST_HEAD(&watcher->u_list);
+
+ spin_lock(&dev->lock);
+ watcher->wd = inotify_dev_get_wd (dev);
+ spin_unlock(&dev->lock);
+
+ if (watcher->wd < 0) {
+ iprintk(INOTIFY_DEBUG_ERRORS, "Could not get wd for watcher %p\n", watcher);
+ iprintk(INOTIFY_DEBUG_ALLOC, "free'd watcher %p\n", watcher);
+ kmem_cache_free (watcher_cache, watcher);
+ watcher = NULL;
+ return watcher;
+ }
+
+ watcher_object_count++;
+ return watcher;
+}
+
+/* Must be called with dev->lock held */
+static void delete_watcher (struct inotify_device *dev, struct inotify_watcher *watcher) {
+ inotify_dev_put_wd (dev, watcher->wd);
+
+ iprintk(INOTIFY_DEBUG_ALLOC, "free'd watcher %p\n", watcher);
+
+ kmem_cache_free (watcher_cache, watcher);
+
+ watcher_object_count--;
+}
+
+
+static struct inotify_watcher *inode_find_dev (struct inode *inode, struct inotify_device *dev) {
+ struct inotify_watcher *watcher;
+
+ watcher = NULL;
+
+ list_for_each_entry (watcher, &inode->watchers, i_list) {
+ if (watcher->dev == dev) {
+ return watcher;
+ }
+
+ }
+ return NULL;
+}
+
+static struct inotify_watcher *dev_find_wd (struct inotify_device *dev, int wd)
+{
+ struct inotify_watcher *watcher;
+
+ list_for_each_entry (watcher, &dev->watchers, d_list) {
+ if (watcher->wd == wd) {
+ return watcher;
+ }
+ }
+ return NULL;
+}
+
+static int inotify_dev_is_watching_inode (struct inotify_device *dev, struct inode *inode) {
+ struct inotify_watcher *watcher;
+
+ list_for_each_entry (watcher, &dev->watchers, d_list) {
+ if (watcher->inode == inode) {
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+static int inotify_dev_add_watcher (struct inotify_device *dev, struct inotify_watcher *watcher) {
+ int error;
+
+ error = 0;
+
+ if (!dev||!watcher) {
+ error = -EINVAL;
+ goto out;
+ }
+
+ if (dev_find_wd (dev, watcher->wd)) {
+ error = -EINVAL;
+ goto out;
+ }
+
+
+ if (dev->watcher_count == MAX_INOTIFY_DEV_WATCHERS) {
+ error = -ENOSPC;
+ goto out;
+ }
+
+ list_add(&watcher->d_list, &dev->watchers);
+out:
+ return error;
+}
+
+static int inotify_dev_rm_watcher (struct inotify_device *dev, struct inotify_watcher *watcher) {
+ int error;
+
+ error = -EINVAL;
+
+ if (watcher) {
+ inotify_dev_queue_event (dev, watcher, IN_IGNORED, NULL);
+
+ list_del(&watcher->d_list);
+
+ error = 0;
+ }
+
+ return error;
+}
+
+void inode_update_watchers_mask (struct inode *inode)
+{
+ struct inotify_watcher *watcher;
+ unsigned long new_mask;
+
+ new_mask = 0;
+ list_for_each_entry(watcher, &inode->watchers, i_list) {
+ new_mask |= watcher->mask;
+ }
+ inode->watchers_mask = new_mask;
+}
+
+static int inode_add_watcher (struct inode *inode, struct inotify_watcher *watcher) {
+ if (!inode||!watcher||inode_find_dev (inode, watcher->dev))
+ return -EINVAL;
+
+ list_add(&watcher->i_list, &inode->watchers);
+ inode->watcher_count++;
+
+ inode_update_watchers_mask (inode);
+
+
+ return 0;
+}
+
+static int inode_rm_watcher (struct inode *inode, struct inotify_watcher *watcher) {
+ if (!inode||!watcher)
+ return -EINVAL;
+
+ list_del(&watcher->i_list);
+ inode->watcher_count--;
+
+ inode_update_watchers_mask (inode);
+
+ return 0;
+}
+
+/* Kernel API */
+
+void inotify_inode_queue_event (struct inode *inode, unsigned long mask, const char *filename) {
+ struct inotify_watcher *watcher;
+
+ spin_lock(&inode->i_lock);
+
+ list_for_each_entry (watcher, &inode->watchers, i_list) {
+ spin_lock(&watcher->dev->lock);
+ inotify_dev_queue_event (watcher->dev, watcher, mask, filename);
+ spin_unlock(&watcher->dev->lock);
+ }
+
+ spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(inotify_inode_queue_event);
+
+void inotify_dentry_parent_queue_event(struct dentry *dentry, unsigned long mask, const char *filename)
+{
+ struct dentry *parent;
+
+ spin_lock(&dentry->d_lock);
+ dget (dentry->d_parent);
+ parent = dentry->d_parent;
+ inotify_inode_queue_event(parent->d_inode, mask, filename);
+ dput (parent);
+ spin_unlock(&dentry->d_lock);
+}
+EXPORT_SYMBOL_GPL(inotify_dentry_parent_queue_event);
+
+static void ignore_helper (struct inotify_watcher *watcher, int event) {
+ struct inotify_device *dev;
+ struct inode *inode;
+
+ spin_lock(&watcher->dev->lock);
+ spin_lock(&watcher->inode->i_lock);
+
+ inode = watcher->inode;
+ dev = watcher->dev;
+
+ if (event)
+ inotify_dev_queue_event (dev, watcher, event, NULL);
+
+ inode_rm_watcher (inode, watcher);
+ inotify_dev_rm_watcher (watcher->dev, watcher);
+ list_del(&watcher->u_list);
+
+
+ spin_unlock(&inode->i_lock);
+
+ delete_watcher(dev, watcher);
+
+ spin_unlock(&dev->lock);
+
+ unref_inode (inode);
+}
+
+static void process_umount_list (struct list_head *umount) {
+ struct inotify_watcher *watcher, *next;
+
+ list_for_each_entry_safe (watcher, next, umount, u_list) {
+ ignore_helper (watcher, IN_UNMOUNT);
+ }
+}
+
+static void build_umount_list (struct list_head *head, struct super_block *sb, struct list_head *umount) {
+ struct inode * inode;
+
+ list_for_each_entry (inode, head, i_list) {
+ struct inotify_watcher *watcher;
+
+ if (inode->i_sb != sb)
+ continue;
+
+ spin_lock(&inode->i_lock);
+
+ list_for_each_entry (watcher, &inode->watchers, i_list) {
+ list_add (&watcher->u_list, umount);
+ }
+
+ spin_unlock(&inode->i_lock);
+ }
+}
+
+void inotify_super_block_umount (struct super_block *sb)
+{
+ struct list_head umount;
+
+ INIT_LIST_HEAD(&umount);
+
+ spin_lock(&inode_lock);
+ build_umount_list (&inode_in_use, sb, &umount);
+ spin_unlock(&inode_lock);
+
+ process_umount_list (&umount);
+}
+EXPORT_SYMBOL_GPL(inotify_super_block_umount);
+
+/* The driver interface is implemented below */
+
+static unsigned int inotify_poll(struct file *file, poll_table *wait) {
+ struct inotify_device *dev;
+
+ dev = file->private_data;
+
+
+ poll_wait(file, &dev->wait, wait);
+
+ if (inotify_dev_has_events(dev)) {
+ return POLLIN | POLLRDNORM;
+ }
+
+ return 0;
+}
+
+#define MAX_EVENTS_AT_ONCE 20
+static ssize_t inotify_read(struct file *file, __user char *buf,
+ size_t count, loff_t *pos) {
+ size_t out;
+ struct inotify_event *eventbuf;
+ struct inotify_kernel_event *kevent;
+ struct inotify_device *dev;
+ char *obuf;
+ int err;
+ DECLARE_WAITQUEUE(wait, current);
+
+ int events;
+ int event_count;
+
+ eventbuf = kmalloc(sizeof(struct inotify_event) * MAX_EVENTS_AT_ONCE,
+ GFP_KERNEL);
+ events = 0;
+ event_count = 0;
+ out = 0;
+ err = 0;
+
+ obuf = buf;
+
+ dev = file->private_data;
+
+ /* We only hand out full inotify events */
+ if (count < sizeof(struct inotify_event)) {
+ out = -EINVAL;
+ goto out;
+ }
+
+ events = count / sizeof(struct inotify_event);
+
+ if (events > MAX_EVENTS_AT_ONCE) events = MAX_EVENTS_AT_ONCE;
+
+ if (!inotify_dev_has_events(dev)) {
+ if (file->f_flags & O_NONBLOCK) {
+ out = -EAGAIN;
+ goto out;
+ }
+ }
+
+ spin_lock_irq(&dev->lock);
+
+ add_wait_queue(&dev->wait, &wait);
+repeat:
+ if (signal_pending(current)) {
+ spin_unlock_irq (&dev->lock);
+ out = -ERESTARTSYS;
+ set_current_state (TASK_RUNNING);
+ remove_wait_queue(&dev->wait, &wait);
+ goto out;
+ }
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!inotify_dev_has_events (dev)) {
+ spin_unlock_irq (&dev->lock);
+ schedule ();
+ spin_lock_irq (&dev->lock);
+ goto repeat;
+ }
+
+ set_current_state (TASK_RUNNING);
+ remove_wait_queue (&dev->wait, &wait);
+
+ err = !access_ok(VERIFY_WRITE, (void *)buf, sizeof(struct inotify_event));
+
+ if (err) {
+ out = -EFAULT;
+ goto out;
+ }
+
+
+ /* Copy all the events we can to the event buffer */
+ for (event_count = 0; event_count < events; event_count++) {
+ kevent = inotify_dev_get_event (dev);
+ eventbuf[event_count] = kevent->event;
+ inotify_dev_event_dequeue (dev);
+ }
+
+ spin_unlock_irq (&dev->lock);
+
+ /* Send the event buffer to user space */
+ err = copy_to_user (buf, eventbuf, events * sizeof(struct inotify_event));
+
+ buf += sizeof(struct inotify_event) * events;
+
+ out = buf - obuf;
+
+out:
+ kfree(eventbuf);
+ return out;
+}
+
+static void inotify_dev_timer (unsigned long data) {
+ struct inotify_device *dev = (struct inotify_device *)data;
+
+ if (!data) return;
+
+ // reset the timer
+ mod_timer(&dev->timer, INOTIFY_DEV_TIMER_TIME);
+
+ // wake up anything waiting on poll
+ if (inotify_dev_has_events (dev)) {
+ wake_up_interruptible(&dev->wait);
+ }
+}
+
+static int inotify_open(struct inode *inode, struct file *file) {
+ struct inotify_device *dev;
+
+ if (atomic_read(&watcher_count) == MAX_INOTIFY_DEVS)
+ return -ENODEV;
+
+ atomic_inc(&watcher_count);
+
+ dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL);
+ dev->bitmask = kmalloc(__BITMASK_SIZE, GFP_KERNEL);
+ memset(dev->bitmask, 0, __BITMASK_SIZE);
+
+ INIT_LIST_HEAD(&dev->events);
+ INIT_LIST_HEAD(&dev->watchers);
+ init_timer(&dev->timer);
+ init_waitqueue_head(&dev->wait);
+
+ atomic_set(&dev->event_count, 0);
+ dev->watcher_count = 0;
+ dev->lock = SPIN_LOCK_UNLOCKED;
+ dev->read_state = 0;
+
+ file->private_data = dev;
+
+ dev->timer.data = dev;
+ dev->timer.function = inotify_dev_timer;
+ dev->timer.expires = INOTIFY_DEV_TIMER_TIME;
+
+ add_timer(&dev->timer);
+
+ printk(KERN_ALERT "inotify device opened\n");
+
+ return 0;
+}
+
+static void inotify_release_all_watchers (struct inotify_device *dev)
+{
+ struct inotify_watcher *watcher,*next;
+
+ list_for_each_entry_safe(watcher, next, &dev->watchers, d_list) {
+ ignore_helper (watcher, 0);
+ }
+}
+
+static void inotify_release_all_events (struct inotify_device *dev)
+{
+ spin_lock(&dev->lock);
+ while (inotify_dev_has_events(dev)) {
+ inotify_dev_event_dequeue(dev);
+ }
+ spin_unlock(&dev->lock);
+}
+
+
+static int inotify_release(struct inode *inode, struct file *file)
+{
+ if (file->private_data) {
+ struct inotify_device *dev;
+
+ dev = (struct inotify_device *)file->private_data;
+
+ del_timer_sync(&dev->timer);
+
+ inotify_release_all_watchers(dev);
+
+ inotify_release_all_events(dev);
+
+ kfree (dev->bitmask);
+ kfree (dev);
+
+ }
+
+ printk(KERN_ALERT "inotify device released\n");
+
+ atomic_dec(&watcher_count);
+ return 0;
+}
+
+static int inotify_watch (struct inotify_device *dev, struct inotify_watch_request *request)
+{
+ int err;
+ struct inode *inode;
+ struct inotify_watcher *watcher;
+ err = 0;
+
+ err = find_inode (request->dirname, &inode);
+
+ if (err)
+ goto exit;
+
+ if (!S_ISDIR(inode->i_mode)) {
+ iprintk(INOTIFY_DEBUG_ERRORS, "watching file\n");
+ }
+
+ spin_lock(&dev->lock);
+ spin_lock(&inode->i_lock);
+
+ /* This handles the case of re-adding a directory we are already
+ * watching, we just update the mask and return 0
+ */
+ if (inotify_dev_is_watching_inode (dev, inode)) {
+ iprintk(INOTIFY_DEBUG_ERRORS, "adjusting event mask for inode %p\n", inode);
+ struct inotify_watcher *owatcher; // the old watcher
+
+ owatcher = inode_find_dev (inode, dev);
+
+ owatcher->mask = request->mask;
+
+ inode_update_watchers_mask (inode);
+
+ spin_unlock (&inode->i_lock);
+ spin_unlock (&dev->lock);
+
+ unref_inode (inode);
+
+ return 0;
+ }
+
+ spin_unlock (&inode->i_lock);
+ spin_unlock (&dev->lock);
+
+
+ watcher = create_watcher (dev, request->mask, inode);
+
+ if (!watcher) {
+ unref_inode (inode);
+ return -ENOSPC;
+ }
+
+ spin_lock(&dev->lock);
+ spin_lock(&inode->i_lock);
+
+ /* We can't add anymore watchers to this device */
+ if (inotify_dev_add_watcher (dev, watcher) == -ENOSPC) {
+ iprintk(INOTIFY_DEBUG_ERRORS, "can't add watcher dev is full\n");
+ spin_unlock (&inode->i_lock);
+ delete_watcher (dev, watcher);
+ spin_unlock (&dev->lock);
+
+ unref_inode (inode);
+ return -ENOSPC;
+ }
+
+ inode_add_watcher (inode, watcher);
+
+ /* We keep a reference on the inode */
+ if (!err) {
+ err = watcher->wd;
+ }
+
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&dev->lock);
+exit:
+ return err;
+}
+
+static int inotify_ignore(struct inotify_device *dev, int wd)
+{
+ struct inotify_watcher *watcher;
+
+ watcher = dev_find_wd (dev, wd);
+
+ if (!watcher) {
+ return -EINVAL;
+ }
+
+ ignore_helper (watcher, 0);
+
+ return 0;
+}
+
+static void inotify_print_stats (struct inotify_device *dev)
+{
+ int sizeof_inotify_watcher;
+ int sizeof_inotify_device;
+ int sizeof_inotify_kernel_event;
+
+ sizeof_inotify_watcher = sizeof (struct inotify_watcher);
+ sizeof_inotify_device = sizeof (struct inotify_device);
+ sizeof_inotify_kernel_event = sizeof (struct inotify_kernel_event);
+
+ printk (KERN_ALERT "GLOBAL INOTIFY STATS\n");
+ printk (KERN_ALERT "watcher_count = %d\n", atomic_read(&watcher_count));
+ printk (KERN_ALERT "event_object_count = %d\n", event_object_count);
+ printk (KERN_ALERT "watcher_object_count = %d\n", watcher_object_count);
+ printk (KERN_ALERT "inode_ref_count = %d\n", inode_ref_count);
+
+ printk (KERN_ALERT "sizeof(struct inotify_watcher) = %d\n", sizeof_inotify_watcher);
+ printk (KERN_ALERT "sizeof(struct inotify_device) = %d\n", sizeof_inotify_device);
+ printk (KERN_ALERT "sizeof(struct inotify_kernel_event) = %d\n", sizeof_inotify_kernel_event);
+
+ spin_lock(&dev->lock);
+
+ printk (KERN_ALERT "inotify device: %p\n", dev);
+ printk (KERN_ALERT "inotify event_count: %d\n", atomic_read(&dev->event_count));
+ printk (KERN_ALERT "inotify watch_count: %d\n", dev->watcher_count);
+
+ spin_unlock(&dev->lock);
+}
+
+static int inotify_ioctl(struct inode *ip, struct file *fp,
+ unsigned int cmd, unsigned long arg) {
+ int err;
+ struct inotify_device *dev;
+ struct inotify_watch_request request;
+ int wid;
+
+ dev = fp->private_data;
+
+ err = 0;
+
+ if (_IOC_TYPE(cmd) != INOTIFY_IOCTL_MAGIC) return -EINVAL;
+ if (_IOC_NR(cmd) > INOTIFY_IOCTL_MAXNR) return -EINVAL;
+
+ if (_IOC_DIR(cmd) & _IOC_READ)
+ err = !access_ok(VERIFY_READ, (void *)arg, _IOC_SIZE(cmd));
+
+ if (err) {
+ err = -EFAULT;
+ goto out;
+ }
+
+ if (_IOC_DIR(cmd) & _IOC_WRITE)
+ err = !access_ok(VERIFY_WRITE, (void *)arg, _IOC_SIZE(cmd));
+
+ if (err) {
+ err = -EFAULT;
+ goto out;
+ }
+
+
+ err = -EINVAL;
+
+ switch (cmd) {
+ case INOTIFY_WATCH:
+ iprintk(INOTIFY_DEBUG_ERRORS, "INOTIFY_WATCH ioctl\n");
+ if (copy_from_user(&request, (void *)arg, sizeof(struct inotify_watch_request))) {
+ err = -EFAULT;
+ goto out;
+ }
+
+ err = inotify_watch(dev, &request);
+ break;
+ case INOTIFY_IGNORE:
+ iprintk(INOTIFY_DEBUG_ERRORS, "INOTIFY_IGNORE ioctl\n");
+ if (copy_from_user(&wid, (void *)arg, sizeof(int))) {
+ err = -EFAULT;
+ goto out;
+ }
+
+ err = inotify_ignore(dev, wid);
+ break;
+ case INOTIFY_STATS:
+ iprintk(INOTIFY_DEBUG_ERRORS, "INOTIFY_STATS ioctl\n");
+ inotify_print_stats (dev);
+ err = 0;
+ break;
+ case INOTIFY_SETDEBUG:
+ iprintk(INOTIFY_DEBUG_ERRORS, "INOTIFY_SETDEBUG ioctl\n");
+ if (copy_from_user(&inotify_debug_flags, (void *)arg, sizeof(int))) {
+ err = -EFAULT;
+ goto out;
+ }
+ break;
+ }
+
+out:
+ return err;
+}
+
+static struct file_operations inotify_fops = {
+ .owner = THIS_MODULE,
+ .poll = inotify_poll,
+ .read = inotify_read,
+ .open = inotify_open,
+ .release = inotify_release,
+ .ioctl = inotify_ioctl,
+};
+
+struct miscdevice inotify_device = {
+ .minor = MISC_DYNAMIC_MINOR, // automatic
+ .name = "inotify",
+ .fops = &inotify_fops,
+};
+
+
+static int __init inotify_init (void)
+{
+ int ret;
+
+ ret = misc_register(&inotify_device);
+
+ if (ret) {
+ goto out;
+ }
+
+ inotify_debug_flags = INOTIFY_DEBUG_NONE;
+
+ watcher_cache = kmem_cache_create ("watcher_cache",
+ sizeof(struct inotify_watcher), 0, SLAB_PANIC, NULL, NULL);
+
+ if (!watcher_cache) {
+ misc_deregister (&inotify_device);
+ }
+ kevent_cache = kmem_cache_create ("kevent_cache",
+ sizeof(struct inotify_kernel_event), 0, SLAB_PANIC, NULL, NULL);
+
+ if (!kevent_cache) {
+ misc_deregister (&inotify_device);
+ kmem_cache_destroy (watcher_cache);
+ }
+
+ printk(KERN_ALERT "inotify 0.9.2 minor=%d\n", inotify_device.minor);
+out:
+ return ret;
+}
+
+static void inotify_exit (void)
+{
+ kmem_cache_destroy (kevent_cache);
+ kmem_cache_destroy (watcher_cache);
+ misc_deregister (&inotify_device);
+ printk(KERN_ALERT "inotify shutdown ec=%d wc=%d ic=%d\n", event_object_count, watcher_object_count, inode_ref_count);
+}
+
+MODULE_AUTHOR("John McCutchan <ttb@tentacle.dhs.org>");
+MODULE_DESCRIPTION("Inode event driver");
+MODULE_LICENSE("GPL");
+
+module_init (inotify_init);
+module_exit (inotify_exit);
diff -urN linux-2.6.8.1/drivers/char/Makefile ../linux/drivers/char/Makefile
--- linux-2.6.8.1/drivers/char/Makefile 2004-08-14 06:56:22.000000000 -0400
+++ ../linux/drivers/char/Makefile 2004-08-19 00:11:52.000000000 -0400
@@ -7,7 +7,7 @@
#
FONTMAPFILE = cp437.uni

-obj-y += mem.o random.o tty_io.o n_tty.o tty_ioctl.o pty.o misc.o
+obj-y += mem.o random.o tty_io.o n_tty.o tty_ioctl.o pty.o misc.o inotify.o

obj-$(CONFIG_VT) += vt_ioctl.o vc_screen.o consolemap.o \
consolemap_deftbl.o selection.o keyboard.o
diff -urN linux-2.6.8.1/fs/attr.c ../linux/fs/attr.c
--- linux-2.6.8.1/fs/attr.c 2004-08-14 06:54:50.000000000 -0400
+++ ../linux/fs/attr.c 2004-08-19 00:11:52.000000000 -0400
@@ -11,6 +11,7 @@
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/dnotify.h>
+#include <linux/inotify.h>
#include <linux/fcntl.h>
#include <linux/quotaops.h>
#include <linux/security.h>
@@ -185,8 +186,11 @@
}
if (!error) {
unsigned long dn_mask = setattr_mask(ia_valid);
- if (dn_mask)
+ if (dn_mask) {
dnotify_parent(dentry, dn_mask);
+ inotify_inode_queue_event (dentry->d_inode, dn_mask, NULL);
+ inotify_dentry_parent_queue_event (dentry, dn_mask, dentry->d_name.name);
+ }
}
return error;
}
diff -urN linux-2.6.8.1/fs/inode.c ../linux/fs/inode.c
--- linux-2.6.8.1/fs/inode.c 2004-08-14 06:56:23.000000000 -0400
+++ ../linux/fs/inode.c 2004-08-19 00:11:52.000000000 -0400
@@ -114,6 +114,7 @@
if (inode) {
struct address_space * const mapping = &inode->i_data;

+ INIT_LIST_HEAD (&inode->watchers);
inode->i_sb = sb;
inode->i_blkbits = sb->s_blocksize_bits;
inode->i_flags = 0;
diff -urN linux-2.6.8.1/fs/namei.c ../linux/fs/namei.c
--- linux-2.6.8.1/fs/namei.c 2004-08-14 06:55:10.000000000 -0400
+++ ../linux/fs/namei.c 2004-09-15 16:43:23.000000000 -0400
@@ -22,6 +22,7 @@
#include <linux/quotaops.h>
#include <linux/pagemap.h>
#include <linux/dnotify.h>
+#include <linux/inotify.h>
#include <linux/smp_lock.h>
#include <linux/personality.h>
#include <linux/security.h>
@@ -1221,6 +1222,7 @@
error = dir->i_op->create(dir, dentry, mode, nd);
if (!error) {
inode_dir_notify(dir, DN_CREATE);
+ inotify_inode_queue_event(dir, IN_CREATE, dentry->d_name.name);
security_inode_post_create(dir, dentry, mode);
}
return error;
@@ -1535,6 +1537,7 @@
error = dir->i_op->mknod(dir, dentry, mode, dev);
if (!error) {
inode_dir_notify(dir, DN_CREATE);
+ inotify_inode_queue_event(dir, IN_CREATE, dentry->d_name.name);
security_inode_post_mknod(dir, dentry, mode, dev);
}
return error;
@@ -1608,6 +1611,7 @@
error = dir->i_op->mkdir(dir, dentry, mode);
if (!error) {
inode_dir_notify(dir, DN_CREATE);
+ inotify_inode_queue_event(dir, IN_CREATE, dentry->d_name.name);
security_inode_post_mkdir(dir,dentry, mode);
}
return error;
@@ -1703,6 +1707,8 @@
up(&dentry->d_inode->i_sem);
if (!error) {
inode_dir_notify(dir, DN_DELETE);
+ inotify_inode_queue_event(dir, IN_DELETE, dentry->d_name.name);
+ inotify_inode_queue_event(dentry->d_inode, IN_DELETE, NULL);
d_delete(dentry);
}
dput(dentry);
@@ -1775,8 +1781,9 @@

/* We don't d_delete() NFS sillyrenamed files--they still exist. */
if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
- d_delete(dentry);
inode_dir_notify(dir, DN_DELETE);
+ inotify_inode_queue_event(dir, IN_DELETE, dentry->d_name.name);
+ d_delete(dentry);
}
return error;
}
@@ -1853,6 +1860,7 @@
error = dir->i_op->symlink(dir, dentry, oldname);
if (!error) {
inode_dir_notify(dir, DN_CREATE);
+ inotify_inode_queue_event(dir, IN_CREATE, dentry->d_name.name);
security_inode_post_symlink(dir, dentry, oldname);
}
return error;
@@ -1926,6 +1934,7 @@
up(&old_dentry->d_inode->i_sem);
if (!error) {
inode_dir_notify(dir, DN_CREATE);
+ inotify_inode_queue_event(dir, IN_CREATE, new_dentry->d_name.name);
security_inode_post_link(old_dentry, dir, new_dentry);
}
return error;
@@ -2115,12 +2124,14 @@
else
error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry);
if (!error) {
- if (old_dir == new_dir)
+ if (old_dir == new_dir) {
inode_dir_notify(old_dir, DN_RENAME);
- else {
+ } else {
inode_dir_notify(old_dir, DN_DELETE);
inode_dir_notify(new_dir, DN_CREATE);
}
+
+ inotify_inode_queue_event(old_dir, IN_RENAME, new_dentry->d_name.name);
}
return error;
}
diff -urN linux-2.6.8.1/fs/open.c ../linux/fs/open.c
--- linux-2.6.8.1/fs/open.c 2004-08-14 06:54:48.000000000 -0400
+++ ../linux/fs/open.c 2004-08-19 00:11:52.000000000 -0400
@@ -11,6 +11,7 @@
#include <linux/smp_lock.h>
#include <linux/quotaops.h>
#include <linux/dnotify.h>
+#include <linux/inotify.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/tty.h>
@@ -955,6 +956,8 @@
error = PTR_ERR(f);
if (IS_ERR(f))
goto out_error;
+ inotify_inode_queue_event (f->f_dentry->d_inode, IN_OPEN, NULL);
+ inotify_dentry_parent_queue_event (f->f_dentry, IN_OPEN, f->f_dentry->d_name.name);
fd_install(fd, f);
}
out:
@@ -1034,6 +1037,8 @@
FD_CLR(fd, files->close_on_exec);
__put_unused_fd(files, fd);
spin_unlock(&files->file_lock);
+ inotify_dentry_parent_queue_event (filp->f_dentry, IN_CLOSE, filp->f_dentry->d_name.name);
+ inotify_inode_queue_event (filp->f_dentry->d_inode, IN_CLOSE, NULL);
return filp_close(filp, files);

out_unlock:
diff -urN linux-2.6.8.1/fs/read_write.c ../linux/fs/read_write.c
--- linux-2.6.8.1/fs/read_write.c 2004-08-14 06:55:35.000000000 -0400
+++ ../linux/fs/read_write.c 2004-08-19 00:11:52.000000000 -0400
@@ -11,6 +11,7 @@
#include <linux/uio.h>
#include <linux/smp_lock.h>
#include <linux/dnotify.h>
+#include <linux/inotify.h>
#include <linux/security.h>
#include <linux/module.h>

@@ -216,8 +217,11 @@
ret = file->f_op->read(file, buf, count, pos);
else
ret = do_sync_read(file, buf, count, pos);
- if (ret > 0)
+ if (ret > 0) {
dnotify_parent(file->f_dentry, DN_ACCESS);
+ inotify_dentry_parent_queue_event(file->f_dentry, IN_ACCESS, file->f_dentry->d_name.name);
+ inotify_inode_queue_event (file->f_dentry->d_inode, IN_ACCESS, NULL);
+ }
}
}

@@ -260,8 +264,11 @@
ret = file->f_op->write(file, buf, count, pos);
else
ret = do_sync_write(file, buf, count, pos);
- if (ret > 0)
+ if (ret > 0) {
dnotify_parent(file->f_dentry, DN_MODIFY);
+ inotify_dentry_parent_queue_event(file->f_dentry, IN_MODIFY, file->f_dentry->d_name.name);
+ inotify_inode_queue_event (file->f_dentry->d_inode, IN_MODIFY, NULL);
+ }
}
}

@@ -493,9 +500,13 @@
out:
if (iov != iovstack)
kfree(iov);
- if ((ret + (type == READ)) > 0)
+ if ((ret + (type == READ)) > 0) {
dnotify_parent(file->f_dentry,
(type == READ) ? DN_ACCESS : DN_MODIFY);
+ inotify_dentry_parent_queue_event(file->f_dentry,
+ (type == READ) ? IN_ACCESS : IN_MODIFY, file->f_dentry->d_name.name);
+ inotify_inode_queue_event (file->f_dentry->d_inode, (type == READ) ? IN_ACCESS : IN_MODIFY, NULL);
+ }
return ret;
}

diff -urN linux-2.6.8.1/fs/super.c ../linux/fs/super.c
--- linux-2.6.8.1/fs/super.c 2004-08-14 06:55:22.000000000 -0400
+++ ../linux/fs/super.c 2004-09-18 02:24:33.000000000 -0400
@@ -36,6 +36,7 @@
#include <linux/writeback.h> /* for the emergency remount stuff */
#include <linux/idr.h>
#include <asm/uaccess.h>
+#include <linux/inotify.h>

void get_filesystem(struct file_system_type *fs);
@@ -204,6 +205,7 @@

if (root) {
sb->s_root = NULL;
+ inotify_super_block_umount (sb);
shrink_dcache_parent(root);
shrink_dcache_anon(&sb->s_anon);
dput(root);
diff -urN linux-2.6.8.1/include/linux/fs.h ../linux/include/linux/fs.h
--- linux-2.6.8.1/include/linux/fs.h 2004-08-14 06:55:09.000000000 -0400
+++ ../linux/include/linux/fs.h 2004-09-18 02:24:33.000000000 -0400
@@ -458,6 +458,10 @@
unsigned long i_dnotify_mask; /* Directory notify events */
struct dnotify_struct *i_dnotify; /* for directory notifications */

+ struct list_head watchers;
+ unsigned long watchers_mask;
+ int watcher_count;
+
unsigned long i_state;
unsigned long dirtied_when; /* jiffies of first dirtying */

diff -urN linux-2.6.8.1/include/linux/inotify.h ../linux/include/linux/inotify.h
--- linux-2.6.8.1/include/linux/inotify.h 1969-12-31 19:00:00.000000000 -0500
+++ ../linux/include/linux/inotify.h 2004-08-19 00:11:52.000000000 -0400
@@ -0,0 +1,74 @@
+/*
+ * Inode based directory notification for Linux
+ *
+ * Copyright (C) 2004 John McCutchan
+ *
+ * Signed-off-by: John McCutchan ttb@tentacle.dhs.org
+ */
+
+#ifndef _LINUX_INOTIFY_H
+#define _LINUX_INOTIFY_H
+
+struct inode;
+struct dentry;
+struct super_block;
+
+struct inotify_event {
+ int wd;
+ int mask;
+ char filename[256];
+ /* When you are watching a directory you will get the filenames
+ * for events like IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE, etc..
+ */
+};
+/* When reading from the device you must provide a buffer
+ * that is a multiple of the sizeof(inotify_event)
+ */
+
+#define IN_ACCESS 0x00000001 /* File was accessed */
+#define IN_MODIFY 0x00000002 /* File was modified */
+#define IN_CREATE 0x00000004 /* File was created */
+#define IN_DELETE 0x00000008 /* File was deleted */
+#define IN_RENAME 0x00000010 /* File was renamed */
+#define IN_ATTRIB 0x00000020 /* File changed attributes */
+#define IN_MOVE 0x00000040 /* File was moved */
+#define IN_UNMOUNT 0x00000080 /* Device file was on, was unmounted */
+#define IN_CLOSE 0x00000100 /* File was closed */
+#define IN_OPEN 0x00000200 /* File was opened */
+#define IN_IGNORED 0x00000400 /* File was ignored */
+#define IN_ALL_EVENTS 0xffffffff /* All the events */
+
+/* ioctl */
+
+/* Fill this and pass it to INOTIFY_WATCH ioctl */
+struct inotify_watch_request {
+ char *dirname; // directory name
+ unsigned long mask; // event mask
+};
+
+#define INOTIFY_IOCTL_MAGIC 'Q'
+#define INOTIFY_IOCTL_MAXNR 4
+
+#define INOTIFY_WATCH _IOR(INOTIFY_IOCTL_MAGIC, 1, struct inotify_watch_request)
+#define INOTIFY_IGNORE _IOR(INOTIFY_IOCTL_MAGIC, 2, int)
+#define INOTIFY_STATS _IOR(INOTIFY_IOCTL_MAGIC, 3, int)
+#define INOTIFY_SETDEBUG _IOR(INOTIFY_IOCTL_MAGIC, 4, int)
+
+#define INOTIFY_DEBUG_NONE 0x00000000
+#define INOTIFY_DEBUG_ALLOC 0x00000001
+#define INOTIFY_DEBUG_EVENTS 0x00000002
+#define INOTIFY_DEBUG_INODE 0x00000004
+#define INOTIFY_DEBUG_ERRORS 0x00000008
+#define INOTIFY_DEBUG_FILEN 0x00000010
+#define INOTIFY_DEBUG_ALL 0xffffffff
+
+/* Kernel API */
+/* Adds events to all watchers on inode that are interested in mask */
+void inotify_inode_queue_event (struct inode *inode, unsigned long mask, const char *filename);
+/* Same as above but uses dentry's inode */
+void inotify_dentry_parent_queue_event (struct dentry *dentry, unsigned long mask, const char *filename);
+/* This will remove all watchers from all inodes on the superblock */
+void inotify_super_block_umount (struct super_block *sb);
+
+#endif
+