[patch] inotify, improved.

Robert Love
2005-06-17T15:18:21Z

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On Thu, 2005-06-16 at 21:35 -0400, Robert Love wrote:

> Yah. This is what I originally did. Because of the current
> implementation of list_empty(), the race is never dangerous (e.g., no
> segfault), we just get false positives/negatives, but that is no
> different than the atomic check, really, since we can race in the
> interim and then we go on and check the list anyhow.
>
> So, let's do it. I'll cook up a patch and updated inotify tomorrow, if
> no one beats me to the punch.

Attached patch removes the atomics and does a lockless list check.

Robert Love

[-- Attachment #2: inotify-0.23-rml-2.6.12-rc6-12.patch --]
[-- Type: text/x-patch, Size: 59059 bytes --]

inotify!

inotify is intended to correct the deficiencies of dnotify, particularly
its inability to scale and its terrible user interface:

* dnotify requires the opening of one fd per each directory
that you intend to watch. This quickly results in too many
open files and pins removable media, preventing unmount.
* dnotify is directory-based. You only learn about changes to
directories. Sure, a change to a file in a directory affects
the directory, but you are then forced to keep a cache of
stat structures.
* dnotify's interface to user-space is awful. Signals?

inotify provides a more usable, simple, powerful solution to file change
notification:

* inotify's interface is a device node, not SIGIO. You open a
single fd to the device node, which is select()-able.
* inotify has an event that says "the filesystem that the item
you were watching is on was unmounted."
* inotify can watch directories or files.

Inotify is currently used by Beagle (a desktop search infrastructure),
Gamin (a FAM replacement), and other projects.

See Documentation/filesystems/inotify.txt.

Signed-off-by: Robert Love <rml@novell.com>

Documentation/filesystems/inotify.txt | 123 ++++
fs/Kconfig | 13
fs/Makefile | 1
fs/attr.c | 33 -
fs/compat.c | 12
fs/file_table.c | 3
fs/inode.c | 9
fs/inotify.c | 983 ++++++++++++++++++++++++++++++++++
fs/namei.c | 30 -
fs/nfsd/vfs.c | 6
fs/open.c | 4
fs/read_write.c | 15
fs/sysfs/file.c | 7
fs/xattr.c | 5
include/linux/fs.h | 6
include/linux/fsnotify.h | 257 ++++++++
include/linux/inotify.h | 124 ++++
include/linux/sched.h | 4
kernel/user.c | 4
19 files changed, 1575 insertions(+), 64 deletions(-)

diff -urN linux-2.6.12-rc6/Documentation/filesystems/inotify.txt linux/Documentation/filesystems/inotify.txt
--- linux-2.6.12-rc6/Documentation/filesystems/inotify.txt 1969-12-31 19:00:00.000000000 -0500
+++ linux/Documentation/filesystems/inotify.txt 2005-06-13 11:28:04.000000000 -0400
@@ -0,0 +1,123 @@
+ inotify
+ a powerful yet simple file change notification system
+
+
+
+Document started 15 Mar 2005 by Robert Love <rml@novell.com>
+
+(i) User Interface
+
+Inotify is controlled by a device node, /dev/inotify. If you do not use udev,
+this device may need to be created manually. First step, open it
+
+ int dev_fd = open ("/dev/inotify", O_RDONLY);
+
+Change events are managed by "watches". A watch is an (object,mask) pair where
+the object is a file or directory and the mask is a bitmask of one or more
+inotify events that the application wishes to receive. See <linux/inotify.h>
+for valid events. A watch is referenced by a watch descriptor, or wd.
+
+Watches are added via a file descriptor.
+
+Watches on a directory will return events on any files inside of the directory.
+
+Adding a watch is simple,
+
+ /* 'wd' represents the watch on fd with mask */
+ struct inotify_request req = { fd, mask };
+ int wd = ioctl (dev_fd, INOTIFY_WATCH, &req);
+
+You can add a large number of files via something like
+
+ for each file to watch {
+ struct inotify_request req;
+ int file_fd;
+
+ file_fd = open (file, O_RDONLY);
+ if (fd < 0) {
+ perror ("open");
+ break;
+ }
+
+ req.fd = file_fd;
+ req.mask = mask;
+
+ wd = ioctl (dev_fd, INOTIFY_WATCH, &req);
+
+ close (fd);
+ }
+
+You can update an existing watch in the same manner, by passing in a new mask.
+
+An existing watch is removed via the INOTIFY_IGNORE ioctl, for example
+
+ ioctl (dev_fd, INOTIFY_IGNORE, wd);
+
+Events are provided in the form of an inotify_event structure that is read(2)
+from /dev/inotify. The filename is of dynamic length and follows the struct.
+It is of size len. The filename is padded with null bytes to ensure proper
+alignment. This padding is reflected in len.
+
+You can slurp multiple events by passing a large buffer, for example
+
+ size_t len = read (fd, buf, BUF_LEN);
+
+Will return as many events as are available and fit in BUF_LEN.
+
+/dev/inotify is also select() and poll() able.
+
+You can find the size of the current event queue via the FIONREAD ioctl.
+
+All watches are destroyed and cleaned up on close.
+
+
+(ii) Internal Kernel Implementation
+
+Each open inotify device is associated with an inotify_device structure.
+
+Each watch is associated with an inotify_watch structure. Watches are chained
+off of each associated device and each associated inode.
+
+See fs/inotify.c for the locking and lifetime rules.
+
+
+(iii) Rationale
+
+Q: What is the design decision behind not tying the watch to the
+open fd of the watched object?
+
+A: Watches are associated with an open inotify device, not an
+open file. This solves the primary problem with dnotify:
+keeping the file open pins the file and thus, worse, pins the
+mount. Dnotify is therefore infeasible for use on a desktop
+system with removable media as the media cannot be unmounted.
+
+Q: What is the design decision behind using an-fd-per-device as
+opposed to an fd-per-watch?
+
+A: An fd-per-watch quickly consumes more file descriptors than
+are allowed, more fd's than are feasible to manage, and more
+fd's than are ideally select()-able. Yes, root can bump the
+per-process fd limit and yes, users can use epoll, but requiring
+both is silly and an extraneous requirement. A watch consumes
+less memory than an open file, separating the number spaces is
+thus sensible. The current design is what user-space developers
+want: Users open the device, once, and add n watches, requiring
+but one fd and no twiddling with fd limits.
+Opening /dev/inotify two thousand times is silly. If we can
+implement user-space's preferences cleanly--and we can, the idr
+layer makes stuff like this trivial--then we should.
+
+Q: Why a device node?
+
+A: The second biggest problem with dnotify is that the user
+interface sucks ass. Signals are a terrible, terrible interface
+for file notification. Or for anything, for that matter. The
+idea solution, from all perspectives, is a file descriptor based
+one that allows basic file I/O and poll/select. Obtaining the
+fd and managing the watches could of been done either via a
+device file or a family of new system calls. We decided to
+implement a device file because adding three or four new system
+calls that mirrored open, close, and ioctl seemed silly. A
+character device makes sense from user-space and was easy to
+implement inside of the kernel.
diff -urN linux-2.6.12-rc6/fs/attr.c linux/fs/attr.c
--- linux-2.6.12-rc6/fs/attr.c 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/attr.c 2005-06-13 11:28:04.000000000 -0400
@@ -10,7 +10,7 @@
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#include <linux/fcntl.h>
#include <linux/quotaops.h>
#include <linux/security.h>
@@ -107,31 +107,8 @@
out:
return error;
}
-
EXPORT_SYMBOL(inode_setattr);

-int setattr_mask(unsigned int ia_valid)
-{
- unsigned long dn_mask = 0;
-
- if (ia_valid & ATTR_UID)
- dn_mask |= DN_ATTRIB;
- if (ia_valid & ATTR_GID)
- dn_mask |= DN_ATTRIB;
- if (ia_valid & ATTR_SIZE)
- dn_mask |= DN_MODIFY;
- /* both times implies a utime(s) call */
- if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
- dn_mask |= DN_ATTRIB;
- else if (ia_valid & ATTR_ATIME)
- dn_mask |= DN_ACCESS;
- else if (ia_valid & ATTR_MTIME)
- dn_mask |= DN_MODIFY;
- if (ia_valid & ATTR_MODE)
- dn_mask |= DN_ATTRIB;
- return dn_mask;
-}
-
int notify_change(struct dentry * dentry, struct iattr * attr)
{
struct inode *inode = dentry->d_inode;
@@ -197,11 +174,9 @@
if (ia_valid & ATTR_SIZE)
up_write(&dentry->d_inode->i_alloc_sem);

- if (!error) {
- unsigned long dn_mask = setattr_mask(ia_valid);
- if (dn_mask)
- dnotify_parent(dentry, dn_mask);
- }
+ if (!error)
+ fsnotify_change(dentry, ia_valid);
+
return error;
}

diff -urN linux-2.6.12-rc6/fs/compat.c linux/fs/compat.c
--- linux-2.6.12-rc6/fs/compat.c 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/compat.c 2005-06-13 11:28:04.000000000 -0400
@@ -37,7 +37,7 @@
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/dirent.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#include <linux/highuid.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
@@ -1307,9 +1307,13 @@
out:
if (iov != iovstack)
kfree(iov);
- if ((ret + (type == READ)) > 0)
- dnotify_parent(file->f_dentry,
- (type == READ) ? DN_ACCESS : DN_MODIFY);
+ if ((ret + (type == READ)) > 0) {
+ struct dentry *dentry = file->f_dentry;
+ if (type == READ)
+ fsnotify_access(dentry);
+ else
+ fsnotify_modify(dentry);
+ }
return ret;
}

diff -urN linux-2.6.12-rc6/fs/file_table.c linux/fs/file_table.c
--- linux-2.6.12-rc6/fs/file_table.c 2005-03-02 02:37:47.000000000 -0500
+++ linux/fs/file_table.c 2005-06-13 11:28:04.000000000 -0400
@@ -16,6 +16,7 @@
#include <linux/eventpoll.h>
#include <linux/mount.h>
#include <linux/cdev.h>
+#include <linux/fsnotify.h>

/* sysctl tunables... */
struct files_stat_struct files_stat = {
@@ -123,6 +124,8 @@
struct inode *inode = dentry->d_inode;

might_sleep();
+
+ fsnotify_close(file);
/*
* The function eventpoll_release() should be the first called
* in the file cleanup chain.
diff -urN linux-2.6.12-rc6/fs/inode.c linux/fs/inode.c
--- linux-2.6.12-rc6/fs/inode.c 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/inode.c 2005-06-13 11:28:07.000000000 -0400
@@ -21,6 +21,7 @@
#include <linux/pagemap.h>
#include <linux/cdev.h>
#include <linux/bootmem.h>
+#include <linux/inotify.h>

/*
* This is needed for the following functions:
@@ -128,6 +129,9 @@
#ifdef CONFIG_QUOTA
memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
#endif
+#ifdef CONFIG_INOTIFY
+ atomic_set(&inode->inotify_watch_count, 0);
+#endif
inode->i_pipe = NULL;
inode->i_bdev = NULL;
inode->i_cdev = NULL;
@@ -202,6 +206,10 @@
INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
spin_lock_init(&inode->i_lock);
i_size_ordered_init(inode);
+#ifdef CONFIG_INOTIFY
+ INIT_LIST_HEAD(&inode->inotify_watches);
+ sema_init(&inode->inotify_sem, 1);
+#endif
}

EXPORT_SYMBOL(inode_init_once);
@@ -346,6 +354,7 @@

down(&iprune_sem);
spin_lock(&inode_lock);
+ inotify_unmount_inodes(&sb->s_inodes);
busy = invalidate_list(&sb->s_inodes, &throw_away);
spin_unlock(&inode_lock);

diff -urN linux-2.6.12-rc6/fs/inotify.c linux/fs/inotify.c
--- linux-2.6.12-rc6/fs/inotify.c 1969-12-31 19:00:00.000000000 -0500
+++ linux/fs/inotify.c 2005-06-17 11:07:19.000000000 -0400
@@ -0,0 +1,983 @@
+/*
+ * fs/inotify.c - inode-based file event notifications
+ *
+ * Authors:
+ * John McCutchan <ttb@tentacle.dhs.org>
+ * Robert Love <rml@novell.com>
+ *
+ * Copyright (C) 2005 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.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/writeback.h>
+#include <linux/inotify.h>
+
+#include <asm/ioctls.h>
+
+static atomic_t inotify_cookie;
+
+static kmem_cache_t *watch_cachep;
+static kmem_cache_t *event_cachep;
+
+static int max_user_devices;
+static int max_user_watches;
+static unsigned int max_queued_events;
+
+/*
+ * Lock ordering:
+ *
+ * dentry->d_lock (used to keep d_move() away from dentry->d_parent)
+ * iprune_sem (synchronize shrink_icache_memory())
+ * inode_lock (protects the super_block->s_inodes list)
+ * inode->inotify_sem (protects inode->inotify_watches and watches->i_list)
+ * inotify_dev->sem (protects inotify_device and watches->d_list)
+ */
+
+/*
+ * Lifetimes of the three main data structures--inotify_device, inode, and
+ * inotify_watch--are managed by reference count.
+ *
+ * inotify_device: Lifetime is from open until release. Additional references
+ * can bump the count via get_inotify_dev() and drop the count via
+ * put_inotify_dev().
+ *
+ * inotify_watch: Lifetime is from create_watch() to destory_watch().
+ * Additional references can bump the count via get_inotify_watch() and drop
+ * the count via put_inotify_watch().
+ *
+ * inode: Pinned so long as the inode is associated with a watch, from
+ * create_watch() to put_inotify_watch().
+ */
+
+/*
+ * struct inotify_device - represents an open instance of an inotify device
+ *
+ * This structure is protected by the semaphore 'sem'.
+ */
+struct inotify_device {
+ wait_queue_head_t wq; /* wait queue for i/o */
+ struct idr idr; /* idr mapping wd -> watch */
+ struct semaphore sem; /* protects this bad boy */
+ struct list_head events; /* list of queued events */
+ struct list_head watches; /* list of watches */
+ atomic_t count; /* reference count */
+ struct user_struct *user; /* user who opened this dev */
+ unsigned int queue_size; /* size of the queue (bytes) */
+ unsigned int event_count; /* number of pending events */
+ unsigned int max_events; /* maximum number of events */
+};
+
+/*
+ * struct inotify_kernel_event - An inotify event, originating from a watch and
+ * queued for user-space. A list of these is attached to each instance of the
+ * device. In read(), this list is walked and all events that can fit in the
+ * buffer are returned.
+ *
+ * Protected by dev->sem of the device in which we are queued.
+ */
+struct inotify_kernel_event {
+ struct inotify_event event; /* the user-space event */
+ struct list_head list; /* entry in inotify_device's list */
+ char *name; /* filename, if any */
+};
+
+/*
+ * struct inotify_watch - represents a watch request on a specific inode
+ *
+ * d_list is protected by dev->sem of the associated watch->dev.
+ * i_list and mask are protected by inode->inotify_sem of the associated inode.
+ * dev, inode, and wd are never written to once the watch is created.
+ */
+struct inotify_watch {
+ struct list_head d_list; /* entry in inotify_device's list */
+ struct list_head i_list; /* entry in inode's list */
+ atomic_t count; /* reference count */
+ struct inotify_device *dev; /* associated device */
+ struct inode *inode; /* associated inode */
+ s32 wd; /* watch descriptor */
+ u32 mask; /* event mask for this watch */
+};
+
+static ssize_t show_max_queued_events(struct class_device *class, char *buf)
+{
+ return sprintf(buf, "%d\n", max_queued_events);
+}
+
+static ssize_t store_max_queued_events(struct class_device *class,
+ const char *buf, size_t count)
+{
+ unsigned int max;
+
+ if (sscanf(buf, "%u", &max) > 0 && max > 0) {
+ max_queued_events = max;
+ return strlen(buf);
+ }
+ return -EINVAL;
+}
+
+static ssize_t show_max_user_devices(struct class_device *class, char *buf)
+{
+ return sprintf(buf, "%d\n", max_user_devices);
+}
+
+static ssize_t store_max_user_devices(struct class_device *class,
+ const char *buf, size_t count)
+{
+ int max;
+
+ if (sscanf(buf, "%d", &max) > 0 && max > 0) {
+ max_user_devices = max;
+ return strlen(buf);
+ }
+ return -EINVAL;
+}
+
+static ssize_t show_max_user_watches(struct class_device *class, char *buf)
+{
+ return sprintf(buf, "%d\n", max_user_watches);
+}
+
+static ssize_t store_max_user_watches(struct class_device *class,
+ const char *buf, size_t count)
+{
+ int max;
+
+ if (sscanf(buf, "%d", &max) > 0 && max > 0) {
+ max_user_watches = max;
+ return strlen(buf);
+ }
+ return -EINVAL;
+}
+
+static CLASS_DEVICE_ATTR(max_queued_events, S_IRUGO | S_IWUSR,
+ show_max_queued_events, store_max_queued_events);
+static CLASS_DEVICE_ATTR(max_user_devices, S_IRUGO | S_IWUSR,
+ show_max_user_devices, store_max_user_devices);
+static CLASS_DEVICE_ATTR(max_user_watches, S_IRUGO | S_IWUSR,
+ show_max_user_watches, store_max_user_watches);
+
+static inline void get_inotify_dev(struct inotify_device *dev)
+{
+ atomic_inc(&dev->count);
+}
+
+static inline void put_inotify_dev(struct inotify_device *dev)
+{
+ if (atomic_dec_and_test(&dev->count)) {
+ atomic_dec(&dev->user->inotify_devs);
+ free_uid(dev->user);
+ kfree(dev);
+ }
+}
+
+static inline void get_inotify_watch(struct inotify_watch *watch)
+{
+ atomic_inc(&watch->count);
+}
+
+/*
+ * put_inotify_watch - decrements the ref count on a given watch. cleans up
+ * the watch and its references if the count reaches zero.
+ */
+static inline void put_inotify_watch(struct inotify_watch *watch)
+{
+ if (atomic_dec_and_test(&watch->count)) {
+ put_inotify_dev(watch->dev);
+ iput(watch->inode);
+ kmem_cache_free(watch_cachep, watch);
+ }
+}
+
+/*
+ * kernel_event - create a new kernel event with the given parameters
+ *
+ * This function can sleep.
+ */
+static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
+ const char *name)
+{
+ struct inotify_kernel_event *kevent;
+
+ kevent = kmem_cache_alloc(event_cachep, GFP_KERNEL);
+ if (unlikely(!kevent))
+ return NULL;
+
+ /* we hand this out to user-space, so zero it just in case */
+ memset(&kevent->event, 0, sizeof(struct inotify_event));
+
+ kevent->event.wd = wd;
+ kevent->event.mask = mask;
+ kevent->event.cookie = cookie;
+
+ INIT_LIST_HEAD(&kevent->list);
+
+ if (name) {
+ size_t len, rem, event_size = sizeof(struct inotify_event);
+
+ /*
+ * We need to pad the filename so as to properly align an
+ * array of inotify_event structures. Because the structure is
+ * small and the common case is a small filename, we just round
+ * up to the next multiple of the structure's sizeof. This is
+ * simple and safe for all architectures.
+ */
+ len = strlen(name) + 1;
+ rem = event_size - len;
+ if (len > event_size) {
+ rem = event_size - (len % event_size);
+ if (len % event_size == 0)
+ rem = 0;
+ }
+
+ kevent->name = kmalloc(len + rem, GFP_KERNEL);
+ if (unlikely(!kevent->name)) {
+ kmem_cache_free(event_cachep, kevent);
+ return NULL;
+ }
+ memcpy(kevent->name, name, len);
+ if (rem)
+ memset(kevent->name + len, 0, rem);
+ kevent->event.len = len + rem;
+ } else {
+ kevent->event.len = 0;
+ kevent->name = NULL;
+ }
+
+ return kevent;
+}
+
+/*
+ * inotify_dev_get_event - return the next event in the given dev's queue
+ *
+ * Caller must hold dev->sem.
+ */
+static inline struct inotify_kernel_event *
+inotify_dev_get_event(struct inotify_device *dev)
+{
+ return list_entry(dev->events.next, struct inotify_kernel_event, list);
+}
+
+/*
+ * inotify_dev_queue_event - add a new event to the given device
+ *
+ * Caller must hold dev->sem. Can sleep (calls kernel_event()).
+ */
+static void inotify_dev_queue_event(struct inotify_device *dev,
+ struct inotify_watch *watch, u32 mask,
+ u32 cookie, const char *name)
+{
+ struct inotify_kernel_event *kevent, *last;
+
+ /* coalescing: drop this event if it is a dupe of the previous */
+ last = inotify_dev_get_event(dev);
+ if (last && last->event.mask == mask && last->event.wd == watch->wd &&
+ last->event.cookie == cookie) {
+ const char *lastname = last->name;
+
+ if (!name && !lastname)
+ return;
+ if (name && lastname && !strcmp(lastname, name))
+ return;
+ }
+
+ /* the queue overflowed and we already sent the Q_OVERFLOW event */
+ if (unlikely(dev->event_count > dev->max_events))
+ return;
+
+ /* if the queue overflows, we need to notify user space */
+ if (unlikely(dev->event_count == dev->max_events))
+ kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL);
+ else
+ kevent = kernel_event(watch->wd, mask, cookie, name);
+
+ if (unlikely(!kevent))
+ return;
+
+ /* queue the event and wake up anyone waiting */
+ dev->event_count++;
+ dev->queue_size += sizeof(struct inotify_event) + kevent->event.len;
+ list_add_tail(&kevent->list, &dev->events);
+ wake_up_interruptible(&dev->wq);
+}
+
+/*
+ * remove_kevent - cleans up and ultimately frees the given kevent
+ *
+ * Caller must hold dev->sem.
+ */
+static void remove_kevent(struct inotify_device *dev,
+ struct inotify_kernel_event *kevent)
+{
+ list_del(&kevent->list);
+
+ dev->event_count--;
+ dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len;
+
+ kfree(kevent->name);
+ kmem_cache_free(event_cachep, kevent);
+}
+
+/*
+ * inotify_dev_event_dequeue - destroy an event on the given device
+ *
+ * Caller must hold dev->sem.
+ */
+static void inotify_dev_event_dequeue(struct inotify_device *dev)
+{
+ if (!list_empty(&dev->events)) {
+ struct inotify_kernel_event *kevent;
+ kevent = inotify_dev_get_event(dev);
+ remove_kevent(dev, kevent);
+ }
+}
+
+/*
+ * inotify_dev_get_wd - returns the next WD for use by the given dev
+ *
+ * Callers must hold dev->sem. This function can sleep.
+ */
+static int inotify_dev_get_wd(struct inotify_device *dev,
+ struct inotify_watch *watch)
+{
+ int ret;
+
+ do {
+ if (unlikely(!idr_pre_get(&dev->idr, GFP_KERNEL)))
+ return -ENOSPC;
+ ret = idr_get_new(&dev->idr, watch, &watch->wd);
+ } while (ret == -EAGAIN);
+
+ return ret;
+}
+
+/*
+ * create_watch - creates a watch on the given device.
+ *
+ * Callers must hold dev->sem. Calls inotify_dev_get_wd() so may sleep.
+ * Both 'dev' and 'inode' (by way of nameidata) need to be pinned.
+ */
+static struct inotify_watch *create_watch(struct inotify_device *dev,
+ u32 mask, struct inode *inode)
+{
+ struct inotify_watch *watch;
+ int ret;
+
+ if (atomic_read(&dev->user->inotify_watches) >= max_user_watches)
+ return ERR_PTR(-ENOSPC);
+
+ watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL);
+ if (unlikely(!watch))
+ return ERR_PTR(-ENOMEM);
+
+ ret = inotify_dev_get_wd(dev, watch);
+ if (unlikely(ret)) {
+ kmem_cache_free(watch_cachep, watch);
+ return ERR_PTR(ret);
+ }
+
+ watch->mask = mask;
+ atomic_set(&watch->count, 0);
+ INIT_LIST_HEAD(&watch->d_list);
+ INIT_LIST_HEAD(&watch->i_list);
+
+ /* save a reference to device and bump the count to make it official */
+ get_inotify_dev(dev);
+ watch->dev = dev;
+
+ /*
+ * Save a reference to the inode and bump the ref count to make it
+ * official. We hold a reference to nameidata, which makes this safe.
+ */
+ watch->inode = igrab(inode);
+
+ /* bump our own count, corresponding to our entry in dev->watches */
+ get_inotify_watch(watch);
+
+ atomic_inc(&dev->user->inotify_watches);
+
+ return watch;
+}
+
+/*
+ * inotify_find_dev - find the watch associated with the given inode and dev
+ *
+ * Callers must hold inode->inotify_sem.
+ */
+static struct inotify_watch *inode_find_dev(struct inode *inode,
+ struct inotify_device *dev)
+{
+ struct inotify_watch *watch;
+
+ list_for_each_entry(watch, &inode->inotify_watches, i_list) {
+ if (watch->dev == dev)
+ return watch;
+ }
+
+ return NULL;
+}
+
+/*
+ * remove_watch_no_event - remove_watch() without the IN_IGNORED event.
+ */
+static void remove_watch_no_event(struct inotify_watch *watch,
+ struct inotify_device *dev)
+{
+ list_del(&watch->i_list);
+ list_del(&watch->d_list);
+
+ atomic_dec(&dev->user->inotify_watches);
+ idr_remove(&dev->idr, watch->wd);
+ put_inotify_watch(watch);
+}
+
+/*
+ * remove_watch - Remove a watch from both the device and the inode. Sends
+ * the IN_IGNORED event to the given device signifying that the inode is no
+ * longer watched.
+ *
+ * Callers must hold both inode->inotify_sem and dev->sem. We drop a
+ * reference to the inode before returning.
+ *
+ * The inode is not iput() so as to remain atomic. If the inode needs to be
+ * iput(), the call returns one. Otherwise, it returns zero.
+ */
+static void remove_watch(struct inotify_watch *watch,struct inotify_device *dev)
+{
+ inotify_dev_queue_event(dev, watch, IN_IGNORED, 0, NULL);
+ remove_watch_no_event(watch, dev);
+}
+
+/*
+ * inotify_inode_watched - returns nonzero if there are watches on this inode
+ * and zero otherwise. We call this lockless, we do not care if we race.
+ */
+static inline int inotify_inode_watched(struct inode *inode)
+{
+ return !list_empty(&inode->inotify_watches);
+}
+
+/* Kernel API */
+
+/**
+ * inotify_inode_queue_event - queue an event to all watches on this inode
+ * @inode: inode event is originating from
+ * @mask: event mask describing this event
+ * @cookie: cookie for synchronization, or zero
+ * @name: filename, if any
+ */
+void inotify_inode_queue_event(struct inode *inode, u32 mask, u32 cookie,
+ const char *name)
+{
+ struct inotify_watch *watch, *next;
+
+ if (!inotify_inode_watched(inode))
+ return;
+
+ down(&inode->inotify_sem);
+ list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) {
+ u32 watch_mask = watch->mask;
+ if (watch_mask & mask) {
+ struct inotify_device *dev = watch->dev;
+ get_inotify_watch(watch);
+ down(&dev->sem);
+ inotify_dev_queue_event(dev, watch, mask, cookie, name);
+ if (watch_mask & IN_ONESHOT)
+ remove_watch_no_event(watch, dev);
+ up(&dev->sem);
+ put_inotify_watch(watch);
+ }
+ }
+ up(&inode->inotify_sem);
+}
+EXPORT_SYMBOL_GPL(inotify_inode_queue_event);
+
+/**
+ * inotify_dentry_parent_queue_event - queue an event to a dentry's parent
+ * @dentry: the dentry in question, we queue against this dentry's parent
+ * @mask: event mask describing this event
+ * @cookie: cookie for synchronization, or zero
+ * @name: filename, if any
+ */
+void inotify_dentry_parent_queue_event(struct dentry *dentry, u32 mask,
+ u32 cookie, const char *name)
+{
+ struct dentry *parent;
+ struct inode *inode;
+
+ spin_lock(&dentry->d_lock);
+ parent = dentry->d_parent;
+ inode = parent->d_inode;
+
+ if (inotify_inode_watched(inode)) {
+ dget(parent);
+ spin_unlock(&dentry->d_lock);
+ inotify_inode_queue_event(inode, mask, cookie, name);
+ dput(parent);
+ } else
+ spin_unlock(&dentry->d_lock);
+}
+EXPORT_SYMBOL_GPL(inotify_dentry_parent_queue_event);
+
+/**
+ * inotify_get_cookie - return a unique cookie for use in synchronizing events.
+ */
+u32 inotify_get_cookie(void)
+{
+ return atomic_inc_return(&inotify_cookie);
+}
+EXPORT_SYMBOL_GPL(inotify_get_cookie);
+
+/**
+ * inotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
+ * @list: list of inodes being unmounted (sb->s_inodes)
+ *
+ * Called with inode_lock held, protecting the unmounting super block's list
+ * of inodes, and with iprune_sem held, keeping shrink_icache_memory() at bay.
+ * We temporarily drop inode_lock, however, and CAN block.
+ */
+void inotify_unmount_inodes(struct list_head *list)
+{
+ struct inode *inode, *next_i;
+
+ list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
+ struct inotify_watch *watch, *next_w;
+ struct list_head *watches;
+
+ /*
+ * We cannot __iget() an inode in state I_CLEAR, which is fine
+ * as by that point the inode cannot have any watches.
+ */
+ if (inode->i_state & I_CLEAR)
+ continue;
+
+ /* In case the remove_watch() drops a reference */
+ __iget(inode);
+
+ /*
+ * We can safely drop inode_lock here because the per-sb list
+ * of inodes must not change during unmount and iprune_sem
+ * keeps shrink_icache_memory() away.
+ */
+ spin_unlock(&inode_lock);
+
+ /* for each watch, send IN_UNMOUNT and then remove it */
+ down(&inode->inotify_sem);
+ watches = &inode->inotify_watches;
+ list_for_each_entry_safe(watch, next_w, watches, i_list) {
+ struct inotify_device *dev = watch->dev;
+ down(&dev->sem);
+ inotify_dev_queue_event(dev, watch, IN_UNMOUNT,0,NULL);
+ remove_watch(watch, dev);
+ up(&dev->sem);
+ }
+ up(&inode->inotify_sem);
+ iput(inode);
+
+ spin_lock(&inode_lock);
+ }
+}
+EXPORT_SYMBOL_GPL(inotify_unmount_inodes);
+
+/**
+ * inotify_inode_is_dead - an inode has been deleted, cleanup any watches
+ * @inode: inode that is about to be removed
+ */
+void inotify_inode_is_dead(struct inode *inode)
+{
+ struct inotify_watch *watch, *next;
+
+ down(&inode->inotify_sem);
+ list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) {
+ struct inotify_device *dev = watch->dev;
+ down(&dev->sem);
+ remove_watch(watch, dev);
+ up(&dev->sem);
+ }
+ up(&inode->inotify_sem);
+}
+EXPORT_SYMBOL_GPL(inotify_inode_is_dead);
+
+/* Device Interface */
+
+static unsigned int inotify_poll(struct file *file, poll_table *wait)
+{
+ struct inotify_device *dev = file->private_data;
+ int ret = 0;
+
+ poll_wait(file, &dev->wq, wait);
+ down(&dev->sem);
+ if (!list_empty(&dev->events))
+ ret = POLLIN | POLLRDNORM;
+ up(&dev->sem);
+
+ return ret;
+}
+
+static ssize_t inotify_read(struct file *file, char __user *buf,
+ size_t count, loff_t *pos)
+{
+ size_t event_size = sizeof (struct inotify_event);
+ struct inotify_device *dev;
+ char __user *start;
+ int ret;
+ DEFINE_WAIT(wait);
+
+ start = buf;
+ dev = file->private_data;
+
+ while (1) {
+ int events;
+
+ prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE);
+
+ down(&dev->sem);
+ events = !list_empty(&dev->events);
+ up(&dev->sem);
+ if (events) {
+ ret = 0;
+ break;
+ }
+
+ if (file->f_flags & O_NONBLOCK) {
+ ret = -EAGAIN;
+ break;
+ }
+
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+
+ schedule();
+ }
+
+ finish_wait(&dev->wq, &wait);
+ if (ret)
+ return ret;
+
+ down(&dev->sem);
+ while (1) {
+ struct inotify_kernel_event *kevent;
+
+ ret = buf - start;
+ if (list_empty(&dev->events))
+ break;
+
+ kevent = inotify_dev_get_event(dev);
+ if (event_size + kevent->event.len > count)
+ break;
+
+ if (copy_to_user(buf, &kevent->event, event_size)) {
+ ret = -EFAULT;
+ break;
+ }
+ buf += event_size;
+ count -= event_size;
+
+ if (kevent->name) {
+ if (copy_to_user(buf, kevent->name, kevent->event.len)){
+ ret = -EFAULT;
+ break;
+ }
+ buf += kevent->event.len;
+ count -= kevent->event.len;
+ }
+
+ remove_kevent(dev, kevent);
+ }
+ up(&dev->sem);
+
+ return ret;
+}
+
+static int inotify_open(struct inode *inode, struct file *file)
+{
+ struct inotify_device *dev;
+ struct user_struct *user;
+ int ret;
+
+ user = get_uid(current->user);
+
+ if (unlikely(atomic_read(&user->inotify_devs) >= max_user_devices)) {
+ ret = -EMFILE;
+ goto out_err;
+ }
+
+ dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL);
+ if (unlikely(!dev)) {
+ ret = -ENOMEM;
+ goto out_err;
+ }
+
+ idr_init(&dev->idr);
+ INIT_LIST_HEAD(&dev->events);
+ INIT_LIST_HEAD(&dev->watches);
+ init_waitqueue_head(&dev->wq);
+ sema_init(&dev->sem, 1);
+ dev->event_count = 0;
+ dev->queue_size = 0;
+ dev->max_events = max_queued_events;
+ dev->user = user;
+ atomic_set(&dev->count, 0);
+
+ get_inotify_dev(dev);
+ atomic_inc(&user->inotify_devs);
+
+ file->private_data = dev;
+
+ ret = nonseekable_open(inode, file);
+ if (ret)
+ goto out_err;
+
+ return 0;
+out_err:
+ free_uid(user);
+ return ret;
+}
+
+static int inotify_release(struct inode *ignored, struct file *file)
+{
+ struct inotify_device *dev = file->private_data;
+
+ /*
+ * Destroy all of the watches on this device. Unfortunately, not very
+ * pretty. We cannot do a simple iteration over the list, because we
+ * do not know the inode until we iterate to the watch. But we need to
+ * hold inode->inotify_sem before dev->sem. The following works.
+ */
+ while (1) {
+ struct inotify_watch *watch;
+ struct list_head *watches;
+ struct inode *inode;
+
+ down(&dev->sem);
+ watches = &dev->watches;
+ if (list_empty(watches)) {
+ up(&dev->sem);
+ break;
+ }
+ watch = list_entry(watches->next, struct inotify_watch, d_list);
+ get_inotify_watch(watch);
+ up(&dev->sem);
+
+ inode = watch->inode;
+ down(&inode->inotify_sem);
+ down(&dev->sem);
+ remove_watch_no_event(watch, dev);
+ up(&dev->sem);
+ up(&inode->inotify_sem);
+ put_inotify_watch(watch);
+ }
+
+ /* destroy all of the events on this device */
+ down(&dev->sem);
+ while (!list_empty(&dev->events))
+ inotify_dev_event_dequeue(dev);
+ up(&dev->sem);
+
+ /* free this device: the put matching the get in inotify_open() */
+ put_inotify_dev(dev);
+
+ return 0;
+}
+
+static int inotify_add_watch(struct inotify_device *dev, int fd, u32 mask)
+{
+ struct inotify_watch *watch, *old;
+ struct inode *inode;
+ struct file *filp;
+ int ret;
+
+ filp = fget(fd);
+ if (!filp)
+ return -EBADF;
+ inode = filp->f_dentry->d_inode;
+
+ down(&inode->inotify_sem);
+ down(&dev->sem);
+
+ /* don't let user-space set invalid bits: we don't want flags set */
+ mask &= IN_ALL_EVENTS;
+ if (!mask) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Handle the case of re-adding a watch on an (inode,dev) pair that we
+ * are already watching. We just update the mask and return its wd.
+ */
+ old = inode_find_dev(inode, dev);
+ if (unlikely(old)) {
+ old->mask = mask;
+ ret = old->wd;
+ goto out;
+ }
+
+ watch = create_watch(dev, mask, inode);
+ if (unlikely(IS_ERR(watch))) {
+ ret = PTR_ERR(watch);
+ goto out;
+ }
+
+ /* Add the watch to the device's and the inode's list */
+ list_add(&watch->d_list, &dev->watches);
+ list_add(&watch->i_list, &inode->inotify_watches);
+ ret = watch->wd;
+
+out:
+ up(&dev->sem);
+ up(&inode->inotify_sem);
+ fput(filp);
+
+ return ret;
+}
+
+/*
+ * inotify_ignore - handle the INOTIFY_IGNORE ioctl, asking that a given wd be
+ * removed from the device.
+ *
+ * Can sleep.
+ */
+static int inotify_ignore(struct inotify_device *dev, s32 wd)
+{
+ struct inotify_watch *watch;
+ struct inode *inode;
+
+ down(&dev->sem);
+ watch = idr_find(&dev->idr, wd);
+ if (unlikely(!watch)) {
+ up(&dev->sem);
+ return -EINVAL;
+ }
+ get_inotify_watch(watch);
+ inode = watch->inode;
+ up(&dev->sem);
+
+ down(&inode->inotify_sem);
+ down(&dev->sem);
+
+ /* make sure that we did not race */
+ watch = idr_find(&dev->idr, wd);
+ if (likely(watch))
+ remove_watch(watch, dev);
+
+ up(&dev->sem);
+ up(&inode->inotify_sem);
+ put_inotify_watch(watch);
+
+ return 0;
+}
+
+static long inotify_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct inotify_device *dev;
+ struct inotify_watch_request request;
+ void __user *p;
+ int ret = -ENOTTY;
+ s32 wd;
+
+ dev = file->private_data;
+ p = (void __user *) arg;
+
+ switch (cmd) {
+ case INOTIFY_WATCH:
+ if (unlikely(copy_from_user(&request, p, sizeof (request)))) {
+ ret = -EFAULT;
+ break;
+ }
+ ret = inotify_add_watch(dev, request.fd, request.mask);
+ break;
+ case INOTIFY_IGNORE:
+ if (unlikely(get_user(wd, (int __user *) p))) {
+ ret = -EFAULT;
+ break;
+ }
+ ret = inotify_ignore(dev, wd);
+ break;
+ case FIONREAD:
+ ret = put_user(dev->queue_size, (int __user *) p);
+ break;
+ }
+
+ return ret;
+}
+
+static struct file_operations inotify_fops = {
+ .owner = THIS_MODULE,
+ .poll = inotify_poll,
+ .read = inotify_read,
+ .open = inotify_open,
+ .release = inotify_release,
+ .unlocked_ioctl = inotify_ioctl,
+ .compat_ioctl = inotify_ioctl,
+};
+
+static struct miscdevice inotify_device = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "inotify",
+ .fops = &inotify_fops,
+};
+
+/*
+ * inotify_init - Our initialization function. Note that we cannnot return
+ * error because we have compiled-in VFS hooks. So an (unlikely) failure here
+ * must result in panic().
+ */
+static int __init inotify_init(void)
+{
+ struct class_device *class;
+ int ret;
+
+ ret = misc_register(&inotify_device);
+ if (unlikely(ret))
+ panic("inotify: misc_register returned %d\n", ret);
+
+ max_queued_events = 8192;
+ max_user_devices = 128;
+ max_user_watches = 8192;
+
+ class = inotify_device.class;
+ class_device_create_file(class, &class_device_attr_max_queued_events);
+ class_device_create_file(class, &class_device_attr_max_user_devices);
+ class_device_create_file(class, &class_device_attr_max_user_watches);
+
+ atomic_set(&inotify_cookie, 0);
+
+ watch_cachep = kmem_cache_create("inotify_watch_cache",
+ sizeof(struct inotify_watch),
+ 0, SLAB_PANIC, NULL, NULL);
+ event_cachep = kmem_cache_create("inotify_event_cache",
+ sizeof(struct inotify_kernel_event),
+ 0, SLAB_PANIC, NULL, NULL);
+
+ printk(KERN_INFO "inotify device minor=%d\n", inotify_device.minor);
+
+ return 0;
+}
+
+module_init(inotify_init);
diff -urN linux-2.6.12-rc6/fs/Kconfig linux/fs/Kconfig
--- linux-2.6.12-rc6/fs/Kconfig 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/Kconfig 2005-06-13 11:28:04.000000000 -0400
@@ -339,6 +339,19 @@
If you don't know whether you need it, then you don't need it:
answer N.

+config INOTIFY
+ bool "Inotify file change notification support"
+ default y
+ ---help---
+ Say Y here to enable inotify support and the /dev/inotify character
+ device. Inotify is a file change notification system and a
+ replacement for dnotify. Inotify fixes numerous shortcomings in
+ dnotify and introduces several new features. It allows monitoring
+ of both files and directories via a single open fd. Multiple file
+ events are supported.
+
+ If unsure, say Y.
+
config QUOTA
bool "Quota support"
help
diff -urN linux-2.6.12-rc6/fs/Makefile linux/fs/Makefile
--- linux-2.6.12-rc6/fs/Makefile 2005-03-02 02:38:10.000000000 -0500
+++ linux/fs/Makefile 2005-06-13 11:28:04.000000000 -0400
@@ -11,6 +11,7 @@
attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \

+obj-$(CONFIG_INOTIFY) += inotify.o
obj-$(CONFIG_EPOLL) += eventpoll.o
obj-$(CONFIG_COMPAT) += compat.o

diff -urN linux-2.6.12-rc6/fs/namei.c linux/fs/namei.c
--- linux-2.6.12-rc6/fs/namei.c 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/namei.c 2005-06-13 11:28:04.000000000 -0400
@@ -21,7 +21,7 @@
#include <linux/namei.h>
#include <linux/quotaops.h>
#include <linux/pagemap.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#include <linux/smp_lock.h>
#include <linux/personality.h>
#include <linux/security.h>
@@ -1296,7 +1296,7 @@
DQUOT_INIT(dir);
error = dir->i_op->create(dir, dentry, mode, nd);
if (!error) {
- inode_dir_notify(dir, DN_CREATE);
+ fsnotify_create(dir, dentry->d_name.name);
security_inode_post_create(dir, dentry, mode);
}
return error;
@@ -1602,7 +1602,7 @@
DQUOT_INIT(dir);
error = dir->i_op->mknod(dir, dentry, mode, dev);
if (!error) {
- inode_dir_notify(dir, DN_CREATE);
+ fsnotify_create(dir, dentry->d_name.name);
security_inode_post_mknod(dir, dentry, mode, dev);
}
return error;
@@ -1675,7 +1675,7 @@
DQUOT_INIT(dir);
error = dir->i_op->mkdir(dir, dentry, mode);
if (!error) {
- inode_dir_notify(dir, DN_CREATE);
+ fsnotify_mkdir(dir, dentry->d_name.name);
security_inode_post_mkdir(dir,dentry, mode);
}
return error;
@@ -1766,7 +1766,7 @@
}
up(&dentry->d_inode->i_sem);
if (!error) {
- inode_dir_notify(dir, DN_DELETE);
+ fsnotify_rmdir(dentry, dentry->d_inode, dir);
d_delete(dentry);
}
dput(dentry);
@@ -1839,9 +1839,10 @@

/* We don't d_delete() NFS sillyrenamed files--they still exist. */
if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
+ fsnotify_unlink(dentry, dir);
d_delete(dentry);
- inode_dir_notify(dir, DN_DELETE);
}
+
return error;
}

@@ -1915,7 +1916,7 @@
DQUOT_INIT(dir);
error = dir->i_op->symlink(dir, dentry, oldname);
if (!error) {
- inode_dir_notify(dir, DN_CREATE);
+ fsnotify_create(dir, dentry->d_name.name);
security_inode_post_symlink(dir, dentry, oldname);
}
return error;
@@ -1988,7 +1989,7 @@
error = dir->i_op->link(old_dentry, dir, new_dentry);
up(&old_dentry->d_inode->i_sem);
if (!error) {
- inode_dir_notify(dir, DN_CREATE);
+ fsnotify_create(dir, new_dentry->d_name.name);
security_inode_post_link(old_dentry, dir, new_dentry);
}
return error;
@@ -2152,6 +2153,7 @@
{
int error;
int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
+ const char *old_name;

if (old_dentry->d_inode == new_dentry->d_inode)
return 0;
@@ -2173,18 +2175,18 @@
DQUOT_INIT(old_dir);
DQUOT_INIT(new_dir);

+ old_name = fsnotify_oldname_init(old_dentry->d_name.name);
+
if (is_dir)
error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry);
else
error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry);
if (!error) {
- if (old_dir == new_dir)
- inode_dir_notify(old_dir, DN_RENAME);
- else {
- inode_dir_notify(old_dir, DN_DELETE);
- inode_dir_notify(new_dir, DN_CREATE);
- }
+ const char *new_name = old_dentry->d_name.name;
+ fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir);
}
+ fsnotify_oldname_free(old_name);
+
return error;
}

diff -urN linux-2.6.12-rc6/fs/nfsd/vfs.c linux/fs/nfsd/vfs.c
--- linux-2.6.12-rc6/fs/nfsd/vfs.c 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/nfsd/vfs.c 2005-06-13 11:28:04.000000000 -0400
@@ -45,7 +45,7 @@
#endif /* CONFIG_NFSD_V3 */
#include <linux/nfsd/nfsfh.h>
#include <linux/quotaops.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#ifdef CONFIG_NFSD_V4
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
@@ -861,7 +861,7 @@
nfsdstats.io_read += err;
*count = err;
err = 0;
- dnotify_parent(file->f_dentry, DN_ACCESS);
+ fsnotify_access(file->f_dentry);
} else
err = nfserrno(err);
out:
@@ -917,7 +917,7 @@
set_fs(oldfs);
if (err >= 0) {
nfsdstats.io_write += cnt;
- dnotify_parent(file->f_dentry, DN_MODIFY);
+ fsnotify_modify(file->f_dentry);
}

/* clear setuid/setgid flag after write */
diff -urN linux-2.6.12-rc6/fs/open.c linux/fs/open.c
--- linux-2.6.12-rc6/fs/open.c 2005-03-02 02:37:47.000000000 -0500
+++ linux/fs/open.c 2005-06-13 11:28:04.000000000 -0400
@@ -10,7 +10,7 @@
#include <linux/file.h>
#include <linux/smp_lock.h>
#include <linux/quotaops.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/tty.h>
@@ -944,9 +944,11 @@
fd = get_unused_fd();
if (fd >= 0) {
struct file *f = filp_open(tmp, flags, mode);
+
error = PTR_ERR(f);
if (IS_ERR(f))
goto out_error;
+ fsnotify_open(f->f_dentry);
fd_install(fd, f);
}
out:
diff -urN linux-2.6.12-rc6/fs/read_write.c linux/fs/read_write.c
--- linux-2.6.12-rc6/fs/read_write.c 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/read_write.c 2005-06-13 11:28:04.000000000 -0400
@@ -10,7 +10,7 @@
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/smp_lock.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/syscalls.h>
@@ -239,7 +239,7 @@
else
ret = do_sync_read(file, buf, count, pos);
if (ret > 0) {
- dnotify_parent(file->f_dentry, DN_ACCESS);
+ fsnotify_access(file->f_dentry);
current->rchar += ret;
}
current->syscr++;
@@ -287,7 +287,7 @@
else
ret = do_sync_write(file, buf, count, pos);
if (ret > 0) {
- dnotify_parent(file->f_dentry, DN_MODIFY);
+ fsnotify_modify(file->f_dentry);
current->wchar += ret;
}
current->syscw++;
@@ -523,9 +523,12 @@
out:
if (iov != iovstack)
kfree(iov);
- if ((ret + (type == READ)) > 0)
- dnotify_parent(file->f_dentry,
- (type == READ) ? DN_ACCESS : DN_MODIFY);
+ if ((ret + (type == READ)) > 0) {
+ if (type == READ)
+ fsnotify_access(file->f_dentry);
+ else
+ fsnotify_modify(file->f_dentry);
+ }
return ret;
Efault:
ret = -EFAULT;
diff -urN linux-2.6.12-rc6/fs/sysfs/file.c linux/fs/sysfs/file.c
--- linux-2.6.12-rc6/fs/sysfs/file.c 2005-06-07 15:47:52.000000000 -0400
+++ linux/fs/sysfs/file.c 2005-06-13 11:28:04.000000000 -0400
@@ -3,7 +3,7 @@
*/

#include <linux/module.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#include <linux/kobject.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
@@ -389,9 +389,6 @@
* sysfs_update_file - update the modified timestamp on an object attribute.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
- *
- * Also call dnotify for the dentry, which lots of userspace programs
- * use.
*/
int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
{
@@ -406,7 +403,7 @@
if (victim->d_inode &&
(victim->d_parent->d_inode == dir->d_inode)) {
victim->d_inode->i_mtime = CURRENT_TIME;
- dnotify_parent(victim, DN_MODIFY);
+ fsnotify_modify(victim);

/**
* Drop reference from initial sysfs_get_dentry().
diff -urN linux-2.6.12-rc6/fs/xattr.c linux/fs/xattr.c
--- linux-2.6.12-rc6/fs/xattr.c 2005-03-02 02:38:07.000000000 -0500
+++ linux/fs/xattr.c 2005-06-13 11:28:04.000000000 -0400
@@ -16,6 +16,7 @@
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/module.h>
+#include <linux/fsnotify.h>
#include <asm/uaccess.h>

/*
@@ -57,8 +58,10 @@
if (error)
goto out;
error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
- if (!error)
+ if (!error) {
+ fsnotify_xattr(d);
security_inode_post_setxattr(d, kname, kvalue, size, flags);
+ }
out:
up(&d->d_inode->i_sem);
}
diff -urN linux-2.6.12-rc6/include/linux/fs.h linux/include/linux/fs.h
--- linux-2.6.12-rc6/include/linux/fs.h 2005-06-07 15:47:53.000000000 -0400
+++ linux/include/linux/fs.h 2005-06-17 11:01:37.000000000 -0400
@@ -471,6 +471,11 @@
struct dnotify_struct *i_dnotify; /* for directory notifications */
#endif

+#ifdef CONFIG_INOTIFY
+ struct list_head inotify_watches; /* watches on this inode */
+ struct semaphore inotify_sem; /* protects the watches list */
+#endif
+
unsigned long i_state;
unsigned long dirtied_when; /* jiffies of first dirtying */

@@ -1369,7 +1374,6 @@
extern int do_remount_sb(struct super_block *sb, int flags,
void *data, int force);
extern sector_t bmap(struct inode *, sector_t);
-extern int setattr_mask(unsigned int);
extern int notify_change(struct dentry *, struct iattr *);
extern int permission(struct inode *, int, struct nameidata *);
extern int generic_permission(struct inode *, int,
diff -urN linux-2.6.12-rc6/include/linux/fsnotify.h linux/include/linux/fsnotify.h
--- linux-2.6.12-rc6/include/linux/fsnotify.h 1969-12-31 19:00:00.000000000 -0500
+++ linux/include/linux/fsnotify.h 2005-06-13 11:28:04.000000000 -0400
@@ -0,0 +1,257 @@
+#ifndef _LINUX_FS_NOTIFY_H
+#define _LINUX_FS_NOTIFY_H
+
+/*
+ * include/linux/fsnotify.h - generic hooks for filesystem notification, to
+ * reduce in-source duplication from both dnotify and inotify.
+ *
+ * We don't compile any of this away in some complicated menagerie of ifdefs.
+ * Instead, we rely on the code inside to optimize away as needed.
+ *
+ * (C) Copyright 2005 Robert Love
+ */
+
+#ifdef __KERNEL__
+
+#include <linux/dnotify.h>
+#include <linux/inotify.h>
+
+/*
+ * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
+ */
+static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
+ const char *old_name, const char *new_name,
+ int isdir)
+{
+ u32 cookie = inotify_get_cookie();
+
+ if (old_dir == new_dir)
+ inode_dir_notify(old_dir, DN_RENAME);
+ else {
+ inode_dir_notify(old_dir, DN_DELETE);
+ inode_dir_notify(new_dir, DN_CREATE);
+ }
+
+ if (isdir)
+ isdir = IN_ISDIR;
+ inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir,cookie,old_name);
+ inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, cookie, new_name);
+}
+
+/*
+ * fsnotify_unlink - file was unlinked
+ */
+static inline void fsnotify_unlink(struct dentry *dentry, struct inode *dir)
+{
+ struct inode *inode = dentry->d_inode;
+
+ inode_dir_notify(dir, DN_DELETE);
+ inotify_inode_queue_event(dir, IN_DELETE, 0, dentry->d_name.name);
+ inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL);
+
+ inotify_inode_is_dead(inode);
+}
+
+/*
+ * fsnotify_rmdir - directory was removed
+ */
+static inline void fsnotify_rmdir(struct dentry *dentry, struct inode *inode,
+ struct inode *dir)
+{
+ inode_dir_notify(dir, DN_DELETE);
+ inotify_inode_queue_event(dir,IN_DELETE|IN_ISDIR,0,dentry->d_name.name);
+ inotify_inode_queue_event(inode, IN_DELETE_SELF | IN_ISDIR, 0, NULL);
+ inotify_inode_is_dead(inode);
+}
+
+/*
+ * fsnotify_create - 'name' was linked in
+ */
+static inline void fsnotify_create(struct inode *inode, const char *name)
+{
+ inode_dir_notify(inode, DN_CREATE);
+ inotify_inode_queue_event(inode, IN_CREATE, 0, name);
+}
+
+/*
+ * fsnotify_mkdir - directory 'name' was created
+ */
+static inline void fsnotify_mkdir(struct inode *inode, const char *name)
+{
+ inode_dir_notify(inode, DN_CREATE);
+ inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0, name);
+}
+
+/*
+ * fsnotify_access - file was read
+ */
+static inline void fsnotify_access(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ u32 mask = IN_ACCESS;
+
+ if (S_ISDIR(inode->i_mode))
+ mask |= IN_ISDIR;
+
+ dnotify_parent(dentry, DN_ACCESS);
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+ inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+/*
+ * fsnotify_modify - file was modified
+ */
+static inline void fsnotify_modify(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ u32 mask = IN_MODIFY;
+
+ if (S_ISDIR(inode->i_mode))
+ mask |= IN_ISDIR;
+
+ dnotify_parent(dentry, DN_MODIFY);
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+ inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+/*
+ * fsnotify_open - file was opened
+ */
+static inline void fsnotify_open(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ u32 mask = IN_OPEN;
+
+ if (S_ISDIR(inode->i_mode))
+ mask |= IN_ISDIR;
+
+ inotify_inode_queue_event(inode, mask, 0, NULL);
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+}
+
+/*
+ * fsnotify_close - file was closed
+ */
+static inline void fsnotify_close(struct file *file)
+{
+ struct dentry *dentry = file->f_dentry;
+ struct inode *inode = dentry->d_inode;
+ const char *name = dentry->d_name.name;
+ mode_t mode = file->f_mode;
+ u32 mask = (mode & FMODE_WRITE) ? IN_CLOSE_WRITE : IN_CLOSE_NOWRITE;
+
+ if (S_ISDIR(inode->i_mode))
+ mask |= IN_ISDIR;
+
+ inotify_dentry_parent_queue_event(dentry, mask, 0, name);
+ inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+/*
+ * fsnotify_xattr - extended attributes were changed
+ */
+static inline void fsnotify_xattr(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ u32 mask = IN_ATTRIB;
+
+ if (S_ISDIR(inode->i_mode))
+ mask |= IN_ISDIR;
+
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+ inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+/*
+ * fsnotify_change - notify_change event. file was modified and/or metadata
+ * was changed.
+ */
+static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
+{
+ struct inode *inode = dentry->d_inode;
+ int dn_mask = 0;
+ u32 in_mask = 0;
+
+ if (ia_valid & ATTR_UID) {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ }
+ if (ia_valid & ATTR_GID) {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ }
+ if (ia_valid & ATTR_SIZE) {
+ in_mask |= IN_MODIFY;
+ dn_mask |= DN_MODIFY;
+ }
+ /* both times implies a utime(s) call */
+ if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
+ {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ } else if (ia_valid & ATTR_ATIME) {
+ in_mask |= IN_ACCESS;
+ dn_mask |= DN_ACCESS;
+ } else if (ia_valid & ATTR_MTIME) {
+ in_mask |= IN_MODIFY;
+ dn_mask |= DN_MODIFY;
+ }
+ if (ia_valid & ATTR_MODE) {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ }
+
+ if (dn_mask)
+ dnotify_parent(dentry, dn_mask);
+ if (in_mask) {
+ if (S_ISDIR(inode->i_mode))
+ in_mask |= IN_ISDIR;
+ inotify_inode_queue_event(inode, in_mask, 0, NULL);
+ inotify_dentry_parent_queue_event(dentry, in_mask, 0,
+ dentry->d_name.name);
+ }
+}
+
+#ifdef CONFIG_INOTIFY /* inotify helpers */
+
+/*
+ * fsnotify_oldname_init - save off the old filename before we change it
+ *
+ * XXX: This could be kstrdup if only we could add that to lib/string.c
+ */
+static inline const char *fsnotify_oldname_init(const char *name)
+{
+ size_t len;
+ char *buf;
+
+ len = strlen(name) + 1;
+ buf = kmalloc(len, GFP_KERNEL);
+ if (likely(buf))
+ memcpy(buf, name, len);
+ return buf;
+}
+
+/*
+ * fsnotify_oldname_free - free the name we got from fsnotify_oldname_init
+ */
+static inline void fsnotify_oldname_free(const char *old_name)
+{
+ kfree(old_name);
+}
+
+#else /* CONFIG_INOTIFY */
+
+static inline const char *fsnotify_oldname_init(const char *name)
+{
+ return NULL;
+}
+
+static inline void fsnotify_oldname_free(const char *old_name)
+{
+}
+
+#endif /* ! CONFIG_INOTIFY */
+
+#endif /* __KERNEL__ */
+
+#endif /* _LINUX_FS_NOTIFY_H */
diff -urN linux-2.6.12-rc6/include/linux/inotify.h linux/include/linux/inotify.h
--- linux-2.6.12-rc6/include/linux/inotify.h 1969-12-31 19:00:00.000000000 -0500
+++ linux/include/linux/inotify.h 2005-06-13 11:28:04.000000000 -0400
@@ -0,0 +1,124 @@
+/*
+ * Inode based directory notification for Linux
+ *
+ * Copyright (C) 2005 John McCutchan
+ */
+
+#ifndef _LINUX_INOTIFY_H
+#define _LINUX_INOTIFY_H
+
+#include <linux/types.h>
+
+/*
+ * struct inotify_event - structure read from the inotify device for each event
+ *
+ * When you are watching a directory, you will receive the filename for events
+ * such as IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE, ..., relative to the wd.
+ */
+struct inotify_event {
+ __s32 wd; /* watch descriptor */
+ __u32 mask; /* watch mask */
+ __u32 cookie; /* cookie to synchronize two events */
+ __u32 len; /* length (including nulls) of name */
+ char name[0]; /* stub for possible name */
+};
+
+/*
+ * struct inotify_watch_request - represents a watch request
+ *
+ * Pass to the inotify device via the INOTIFY_WATCH ioctl
+ */
+struct inotify_watch_request {
+ int fd; /* fd of filename to watch */
+ __u32 mask; /* event mask */
+};
+
+/* the following are legal, implemented events that user-space can watch for */
+#define IN_ACCESS 0x00000001 /* File was accessed */
+#define IN_MODIFY 0x00000002 /* File was modified */
+#define IN_ATTRIB 0x00000004 /* Metadata changed */
+#define IN_CLOSE_WRITE 0x00000008 /* Writtable file was closed */
+#define IN_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */
+#define IN_OPEN 0x00000020 /* File was opened */
+#define IN_MOVED_FROM 0x00000040 /* File was moved from X */
+#define IN_MOVED_TO 0x00000080 /* File was moved to Y */
+#define IN_CREATE 0x00000100 /* Subfile was created */
+#define IN_DELETE 0x00000200 /* Subfile was deleted */
+#define IN_DELETE_SELF 0x00000400 /* Self was deleted */
+
+/* the following are legal events. they are sent as needed to any watch */
+#define IN_UNMOUNT 0x00002000 /* Backing fs was unmounted */
+#define IN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
+#define IN_IGNORED 0x00008000 /* File was ignored */
+
+/* helper events */
+#define IN_CLOSE (IN_CLOSE_WRITE | IN_CLOSE_NOWRITE) /* close */
+#define IN_MOVE (IN_MOVED_FROM | IN_MOVED_TO) /* moves */
+
+/* special flags */
+#define IN_ISDIR 0x40000000 /* event occurred against dir */
+#define IN_ONESHOT 0x80000000 /* only send event once */
+
+/*
+ * All of the events - we build the list by hand so that we can add flags in
+ * the future and not break backward compatibility. Apps will get only the
+ * events that they originally wanted. Be sure to add new events here!
+ */
+#define IN_ALL_EVENTS (IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
+ IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
+ IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF)
+
+#define INOTIFY_IOCTL_MAGIC 'Q'
+#define INOTIFY_IOCTL_MAXNR 2
+
+#define INOTIFY_WATCH _IOR(INOTIFY_IOCTL_MAGIC, 1, struct inotify_watch_request)
+#define INOTIFY_IGNORE _IOR(INOTIFY_IOCTL_MAGIC, 2, int)
+
+#ifdef __KERNEL__
+
+#include <linux/dcache.h>
+#include <linux/fs.h>
+#include <linux/config.h>
+
+#ifdef CONFIG_INOTIFY
+
+extern void inotify_inode_queue_event(struct inode *, __u32, __u32,
+ const char *);
+extern void inotify_dentry_parent_queue_event(struct dentry *, __u32, __u32,
+ const char *);
+extern void inotify_unmount_inodes(struct list_head *);
+extern void inotify_inode_is_dead(struct inode *);
+extern u32 inotify_get_cookie(void);
+
+#else
+
+static inline void inotify_inode_queue_event(struct inode *inode,
+ __u32 mask, __u32 cookie,
+ const char *filename)
+{
+}
+
+static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
+ __u32 mask, __u32 cookie,
+ const char *filename)
+{
+}
+
+static inline void inotify_unmount_inodes(struct list_head *list)
+{
+}
+
+static inline void inotify_inode_is_dead(struct inode *inode)
+{
+}
+
+static inline u32 inotify_get_cookie(void)
+{
+ return 0;
+}
+
+#endif /* CONFIG_INOTIFY */
+
+#endif /* __KERNEL __ */
+
+#endif /* _LINUX_INOTIFY_H */
diff -urN linux-2.6.12-rc6/include/linux/sched.h linux/include/linux/sched.h
--- linux-2.6.12-rc6/include/linux/sched.h 2005-06-07 15:47:53.000000000 -0400
+++ linux/include/linux/sched.h 2005-06-13 11:28:04.000000000 -0400
@@ -404,6 +404,10 @@
atomic_t processes; /* How many processes does this user have? */
atomic_t files; /* How many open files does this user have? */
atomic_t sigpending; /* How many pending signals does this user have? */
+#ifdef CONFIG_INOTIFY
+ atomic_t inotify_watches; /* How many inotify watches does this user have? */
+ atomic_t inotify_devs; /* How many inotify devs does this user have opened? */
+#endif
/* protected by mq_lock */
unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */
unsigned long locked_shm; /* How many pages of mlocked shm ? */
diff -urN linux-2.6.12-rc6/kernel/user.c linux/kernel/user.c
--- linux-2.6.12-rc6/kernel/user.c 2005-06-07 15:47:53.000000000 -0400
+++ linux/kernel/user.c 2005-06-13 11:28:04.000000000 -0400
@@ -120,6 +120,10 @@
atomic_set(&new->processes, 0);
atomic_set(&new->files, 0);
atomic_set(&new->sigpending, 0);
+#ifdef CONFIG_INOTIFY
+ atomic_set(&new->inotify_watches, 0);
+ atomic_set(&new->inotify_devs, 0);
+#endif

new->mq_bytes = 0;
new->locked_shm = 0;