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    Subject[patch] inotify 0.22 for 2.6.12-rc1-mm4
    From
    Date
    On Mon, 2005-04-04 at 16:02 -0400, Robert Love wrote:

    Greetings, Mr Morton.

    > Below, find inotify 0.22, against 2.6.12-rc1.
    >
    > This release introduces a conversion in our primary locking from
    > spinlocks to semaphores. Semaphores are a more natural fit for our
    > code, which synchronizes with user-space, thus we clean up a bit of code
    > with a net reduction of 63 lines. Also, I was able to remove the
    > GFP_ATOMIC allocation.
    >
    > I did this as a bit of an experiment, not to fix any specific problem,
    > and I now think it is the right way to go.
    >
    > This release also fixes a small bug in the coalescing code, which could
    > of mistakenly dropped a move event. We now verify that the cookies
    > match before coalescing.

    And a patch for 2.6.12-rc1-mm4.

    Robert Love


    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)
    and Gamin (a FAM replacement).

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

    Documentation/filesystems/inotify.txt | 81 ++
    fs/Kconfig | 13
    fs/Makefile | 1
    fs/attr.c | 33 -
    fs/compat.c | 12
    fs/file_table.c | 3
    fs/inode.c | 6
    fs/inotify.c | 979 ++++++++++++++++++++++++++++++++++
    fs/namei.c | 30 -
    fs/open.c | 6
    fs/read_write.c | 15
    include/linux/fs.h | 6
    include/linux/fsnotify.h | 228 +++++++
    include/linux/inotify.h | 113 +++
    include/linux/sched.h | 4
    kernel/user.c | 4
    16 files changed, 1478 insertions(+), 56 deletions(-)

    diff -urN linux-2.6.12-rc1-mm4/Documentation/filesystems/inotify.txt linux/Documentation/filesystems/inotify.txt
    --- linux-2.6.12-rc1-mm4/Documentation/filesystems/inotify.txt 1969-12-31 19:00:00.000000000 -0500
    +++ linux/Documentation/filesystems/inotify.txt 2005-04-04 13:32:02.000000000 -0400
    @@ -0,0 +1,81 @@
    + 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.
    diff -urN linux-2.6.12-rc1-mm4/fs/attr.c linux/fs/attr.c
    --- linux-2.6.12-rc1-mm4/fs/attr.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/attr.c 2005-04-04 13:32:02.000000000 -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-rc1-mm4/fs/compat.c linux/fs/compat.c
    --- linux-2.6.12-rc1-mm4/fs/compat.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/compat.c 2005-04-04 13:32:02.000000000 -0400
    @@ -36,7 +36,7 @@
    #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>
    @@ -1233,9 +1233,13 @@
    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-rc1-mm4/fs/file_table.c linux/fs/file_table.c
    --- linux-2.6.12-rc1-mm4/fs/file_table.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/file_table.c 2005-04-04 13:32:02.000000000 -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-rc1-mm4/fs/inode.c linux/fs/inode.c
    --- linux-2.6.12-rc1-mm4/fs/inode.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/inode.c 2005-04-04 13:32:02.000000000 -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:
    @@ -132,6 +133,10 @@
    #ifdef CONFIG_QUOTA
    memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
    #endif
    +#ifdef CONFIG_INOTIFY
    + INIT_LIST_HEAD(&inode->inotify_watches);
    + sema_init(&inode->inotify_sem, 1);
    +#endif
    inode->i_pipe = NULL;
    inode->i_bdev = NULL;
    inode->i_cdev = NULL;
    @@ -358,6 +363,7 @@

    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-rc1-mm4/fs/inotify.c linux/fs/inotify.c
    --- linux-2.6.12-rc1-mm4/fs/inotify.c 1969-12-31 19:00:00.000000000 -0500
    +++ linux/fs/inotify.c 2005-04-04 13:32:02.000000000 -0400
    @@ -0,0 +1,979 @@
    +/*
    + * 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 versus 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 list_head events; /* list of queued events */
    + struct list_head watches; /* list of watches */
    + struct semaphore sem; /* protects this bad boy */
    + 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 intofiy 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 dev->watches.
    + * 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;
    + }
    + len += rem;
    +
    + kevent->name = kmalloc(len, GFP_KERNEL);
    + if (unlikely(!kevent->name)) {
    + kmem_cache_free(event_cachep, kevent);
    + return NULL;
    + }
    + memset(kevent->name, 0, len);
    + strncpy(kevent->name, name, strlen(name));
    + kevent->event.len = len;
    + } 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 (dev->event_count && last->event.mask == mask &&
    + last->event.cookie == cookie &&
    + last->event.wd == watch->wd) {
    + 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
    + */
    +static void remove_kevent(struct inotify_device *dev,
    + struct inotify_kernel_event *kevent)
    +{
    + BUG_ON(!dev);
    + BUG_ON(!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;
    +
    + if (atomic_read(&dev->user->inotify_watches) >= max_user_watches)
    + return NULL;
    +
    + watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL);
    + if (unlikely(!watch))
    + return NULL;
    +
    + if (unlikely(inotify_dev_get_wd(dev, watch))) {
    + kmem_cache_free(watch_cachep, watch);
    + return NULL;
    + }
    +
    + 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;
    +}
    +
    +/*
    + * inotify_dev_is_watching_inode - is this device watching this inode?
    + *
    + * Callers must hold dev->sem.
    + */
    +static inline int inotify_dev_is_watching_inode(struct inotify_device *dev,
    + struct inode *inode)
    +{
    + struct inotify_watch *watch;
    +
    + list_for_each_entry(watch, &dev->watches, d_list) {
    + if (watch->inode == inode)
    + return 1;
    + }
    +
    + return 0;
    +}
    +
    +/*
    + * 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)
    +{
    + BUG_ON(!dev);
    + BUG_ON(!watch);
    +
    + 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);
    +}
    +
    +/* 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;
    +
    + down(&inode->inotify_sem);
    + list_for_each_entry(watch, &inode->inotify_watches, i_list) {
    + if (watch->mask & mask) {
    + struct inotify_device *dev = watch->dev;
    + down(&dev->sem);
    + inotify_dev_queue_event(dev, watch, mask, cookie, name);
    + up(&dev->sem);
    + }
    + }
    + 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;
    +
    + /* We intentially do this lockless. The race is fine. */
    + if (!list_empty(&inode->inotify_watches)) {
    + 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.
    + *
    + * Returns the unique cookie.
    + */
    +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 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);
    +
    + 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;
    + int ret = 0;
    +
    + dev = file->private_data;
    + get_inotify_dev(dev);
    +
    + poll_wait(file, &dev->wq, wait);
    + down(&dev->sem);
    + if (!list_empty(&dev->events))
    + ret = POLLIN | POLLRDNORM;
    + up(&dev->sem);
    +
    + put_inotify_dev(dev);
    + return ret;
    +}
    +
    +static ssize_t inotify_read(struct file *file, char __user *buf,
    + size_t count, loff_t *pos)
    +{
    + size_t event_size;
    + struct inotify_device *dev;
    + char __user *start;
    + int ret;
    + DEFINE_WAIT(wait);
    +
    + start = buf;
    + dev = file->private_data;
    +
    + /* we only hand out full inotify events */
    + event_size = sizeof(struct inotify_event);
    + if (count < event_size)
    + return 0;
    +
    + 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(&current->user->inotify_devs);
    +
    + file->private_data = dev;
    +
    + 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;
    +
    + BUG_ON(!dev);
    +
    + /*
    + * 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);
    +
    + /*
    + * 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(!watch)) {
    + ret = -ENOSPC;
    + 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);
    + get_inotify_watch(watch);
    + up(&dev->sem);
    +
    + if (unlikely(!watch))
    + return -EINVAL;
    +
    + inode = watch->inode;
    + down(&inode->inotify_sem);
    + down(&dev->sem);
    + 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;
    +
    + get_inotify_dev(dev);
    +
    + 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(copy_from_user(&wd, p, sizeof (wd)))) {
    + ret = -EFAULT;
    + break;
    + }
    + ret = inotify_ignore(dev, wd);
    + break;
    + case FIONREAD:
    + ret = put_user(dev->queue_size, (int __user *) p);
    + break;
    + }
    +
    + put_inotify_dev(dev);
    +
    + 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 = 512;
    + max_user_devices = 64;
    + max_user_watches = 16384;
    +
    + 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-rc1-mm4/fs/Kconfig linux/fs/Kconfig
    --- linux-2.6.12-rc1-mm4/fs/Kconfig 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/Kconfig 2005-04-04 13:32:02.000000000 -0400
    @@ -341,6 +341,19 @@
    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-rc1-mm4/fs/Makefile linux/fs/Makefile
    --- linux-2.6.12-rc1-mm4/fs/Makefile 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/Makefile 2005-04-04 13:32:02.000000000 -0400
    @@ -12,6 +12,7 @@
    seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
    ioprio.o

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

    diff -urN linux-2.6.12-rc1-mm4/fs/namei.c linux/fs/namei.c
    --- linux-2.6.12-rc1-mm4/fs/namei.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/namei.c 2005-04-04 13:32:02.000000000 -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;
    @@ -1601,7 +1601,7 @@
    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;
    @@ -1674,7 +1674,7 @@
    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;
    @@ -1765,7 +1765,7 @@
    }
    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);
    @@ -1838,9 +1838,10 @@

    /* 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;
    }

    @@ -1914,7 +1915,7 @@
    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;
    @@ -1987,7 +1988,7 @@
    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;
    @@ -2151,6 +2152,7 @@
    {
    int error;
    int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
    + char *old_name;

    if (old_dentry->d_inode == new_dentry->d_inode)
    return 0;
    @@ -2172,18 +2174,18 @@
    DQUOT_INIT(old_dir);
    DQUOT_INIT(new_dir);

    + old_name = fsnotify_oldname_init(old_dentry);
    +
    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);
    }
    + fsnotify_oldname_free(old_name);
    +
    return error;
    }

    diff -urN linux-2.6.12-rc1-mm4/fs/open.c linux/fs/open.c
    --- linux-2.6.12-rc1-mm4/fs/open.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/open.c 2005-04-04 13:32:02.000000000 -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:
    @@ -998,7 +1000,7 @@
    retval = err;
    }

    - dnotify_flush(filp, id);
    + fsnotify_flush(filp, id);
    locks_remove_posix(filp, id);
    fput(filp);
    return retval;
    diff -urN linux-2.6.12-rc1-mm4/fs/read_write.c linux/fs/read_write.c
    --- linux-2.6.12-rc1-mm4/fs/read_write.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/fs/read_write.c 2005-04-04 13:32:02.000000000 -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-rc1-mm4/include/linux/fs.h linux/include/linux/fs.h
    --- linux-2.6.12-rc1-mm4/include/linux/fs.h 2005-03-31 14:04:49.000000000 -0500
    +++ linux/include/linux/fs.h 2005-04-04 13:32:02.000000000 -0400
    @@ -476,6 +476,11 @@
    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 */

    @@ -1391,7 +1396,6 @@
    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-rc1-mm4/include/linux/fsnotify.h linux/include/linux/fsnotify.h
    --- linux-2.6.12-rc1-mm4/include/linux/fsnotify.h 1969-12-31 19:00:00.000000000 -0500
    +++ linux/include/linux/fsnotify.h 2005-04-04 13:32:02.000000000 -0400
    @@ -0,0 +1,228 @@
    +#ifndef _LINUX_FS_NOTIFY_H
    +#define _LINUX_FS_NOTIFY_H
    +
    +/*
    + * include/linux/fs_notify.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)
    +{
    + u32 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);
    + }
    +
    + cookie = inotify_get_cookie();
    +
    + inotify_inode_queue_event(old_dir, IN_MOVED_FROM, cookie, old_name);
    + inotify_inode_queue_event(new_dir, IN_MOVED_TO, 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_FILE, 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_SUBDIR,0,dentry->d_name.name);
    + inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL);
    +
    + inotify_inode_is_dead(inode);
    +}
    +
    +/*
    + * fsnotify_create - filename was linked in
    + */
    +static inline void fsnotify_create(struct inode *inode, const char *filename)
    +{
    + inode_dir_notify(inode, DN_CREATE);
    + inotify_inode_queue_event(inode, IN_CREATE_FILE, 0, filename);
    +}
    +
    +/*
    + * 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_SUBDIR, 0, name);
    +}
    +
    +/*
    + * fsnotify_access - file was read
    + */
    +static inline void fsnotify_access(struct dentry *dentry)
    +{
    + dnotify_parent(dentry, DN_ACCESS);
    + inotify_dentry_parent_queue_event(dentry, IN_ACCESS, 0,
    + dentry->d_name.name);
    + inotify_inode_queue_event(dentry->d_inode, IN_ACCESS, 0, NULL);
    +}
    +
    +/*
    + * fsnotify_modify - file was modified
    + */
    +static inline void fsnotify_modify(struct dentry *dentry)
    +{
    + dnotify_parent(dentry, DN_MODIFY);
    + inotify_dentry_parent_queue_event(dentry, IN_MODIFY, 0,
    + dentry->d_name.name);
    + inotify_inode_queue_event(dentry->d_inode, IN_MODIFY, 0, NULL);
    +}
    +
    +/*
    + * fsnotify_open - file was opened
    + */
    +static inline void fsnotify_open(struct dentry *dentry)
    +{
    + inotify_inode_queue_event(dentry->d_inode, IN_OPEN, 0, NULL);
    + inotify_dentry_parent_queue_event(dentry, IN_OPEN, 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 *filename = dentry->d_name.name;
    + mode_t mode = file->f_mode;
    + u32 mask;
    +
    + mask = (mode & FMODE_WRITE) ? IN_CLOSE_WRITE : IN_CLOSE_NOWRITE;
    + inotify_dentry_parent_queue_event(dentry, mask, 0, filename);
    + 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)
    +{
    + 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) {
    + inotify_inode_queue_event(dentry->d_inode, in_mask, 0, NULL);
    + inotify_dentry_parent_queue_event(dentry, in_mask, 0,
    + dentry->d_name.name);
    + }
    +}
    +
    +/*
    + * fsnotify_flush - flush time!
    + */
    +static inline void fsnotify_flush(struct file *filp, fl_owner_t id)
    +{
    + dnotify_flush(filp, id);
    +}
    +
    +#ifdef CONFIG_INOTIFY /* inotify helpers */
    +
    +/*
    + * fsnotify_oldname_init - save off the old filename before we change it
    + *
    + * this could be kstrdup if only we could add that to lib/string.c
    + */
    +static inline char *fsnotify_oldname_init(struct dentry *old_dentry)
    +{
    + char *old_name;
    +
    + old_name = kmalloc(strlen(old_dentry->d_name.name) + 1, GFP_KERNEL);
    + if (old_name)
    + strcpy(old_name, old_dentry->d_name.name);
    + return old_name;
    +}
    +
    +/*
    + * 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 char *fsnotify_oldname_init(struct dentry *old_dentry)
    +{
    + 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-rc1-mm4/include/linux/inotify.h linux/include/linux/inotify.h
    --- linux-2.6.12-rc1-mm4/include/linux/inotify.h 1969-12-31 19:00:00.000000000 -0500
    +++ linux/include/linux/inotify.h 2005-04-04 13:32:02.000000000 -0400
    @@ -0,0 +1,113 @@
    +/*
    + * Inode based directory notification for Linux
    + *
    + * Copyright (C) 2005 John McCutchan
    + */
    +
    +#ifndef _LINUX_INOTIFY_H
    +#define _LINUX_INOTIFY_H
    +
    +#include <linux/types.h>
    +#include <linux/limits.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 */
    +#define IN_ACCESS 0x00000001 /* File was accessed */
    +#define IN_MODIFY 0x00000002 /* File was modified */
    +#define IN_ATTRIB 0x00000004 /* File changed attributes */
    +#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_DELETE_SUBDIR 0x00000100 /* Subdir was deleted */
    +#define IN_DELETE_FILE 0x00000200 /* Subfile was deleted */
    +#define IN_CREATE_SUBDIR 0x00000400 /* Subdir was created */
    +#define IN_CREATE_FILE 0x00000800 /* Subfile was created */
    +#define IN_DELETE_SELF 0x00001000 /* Self was deleted */
    +#define IN_UNMOUNT 0x00002000 /* Backing fs was unmounted */
    +#define IN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
    +#define IN_IGNORED 0x00008000 /* File was ignored */
    +
    +/* special flags */
    +#define IN_ALL_EVENTS 0xffffffff /* All the events */
    +#define IN_CLOSE (IN_CLOSE_WRITE | IN_CLOSE_NOWRITE)
    +
    +#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>
    +#include <asm/atomic.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-rc1-mm4/include/linux/sched.h linux/include/linux/sched.h
    --- linux-2.6.12-rc1-mm4/include/linux/sched.h 2005-03-31 14:04:49.000000000 -0500
    +++ linux/include/linux/sched.h 2005-04-04 13:32:02.000000000 -0400
    @@ -421,6 +421,10 @@
    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-rc1-mm4/kernel/user.c linux/kernel/user.c
    --- linux-2.6.12-rc1-mm4/kernel/user.c 2005-03-31 14:04:49.000000000 -0500
    +++ linux/kernel/user.c 2005-04-04 13:32:02.000000000 -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;

    -
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