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[PATCH] inotify

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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 system call that returns a fd, not SIGIO.
	  You get a single fd, 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>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Robert Love 2005-07-12 17:06:03 -04:00 committed by Linus Torvalds
parent bd4c625c06
commit 0eeca28300
24 changed files with 1639 additions and 67 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

138
Documentation/filesystems/inotify.txt Normal file
View file

@ -0,0 +1,138 @@
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 set of three sys calls
First step in using inotify is to initialise an inotify instance
int fd = inotify_init ();
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 bit mask 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 path to the file.
Watches on a directory will return events on any files inside of the directory.
Adding a watch is simple,
int wd = inotify_add_watch (fd, path, mask);
You can add a large number of files via something like
for each file to watch {
int wd = inotify_add_watch (fd, file, mask);
}
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
inotify_rm_watch (fd, wd);
Events are provided in the form of an inotify_event structure that is read(2)
from a inotify instance fd. 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.
each inotify instance fd 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 instance 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 optimally
select()-able. Yes, root can bump the per-process fd limit and yes, users
can use epoll, but requiring both is a silly and 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 initialize inotify, once, and add n watches, requiring but one fd
and no twiddling with fd limits. Initializing an inotify instance 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.
There are other good arguments. With a single fd, there is a single
item to block on, which is mapped to a single queue of events. The single
fd returns all watch events and also any potential out-of-band data. If
every fd was a separate watch,
- There would be no way to get event ordering. Events on file foo and
file bar would pop poll() on both fd's, but there would be no way to tell
which happened first. A single queue trivially gives you ordering. Such
ordering is crucial to existing applications such as Beagle. Imagine
"mv a b ; mv b a" events without ordering.
- We'd have to maintain n fd's and n internal queues with state,
versus just one. It is a lot messier in the kernel. A single, linear
queue is the data structure that makes sense.
- User-space developers prefer the current API. The Beagle guys, for
example, love it. Trust me, I asked. It is not a surprise: Who'd want
to manage and block on 1000 fd's via select?
- You'd have to manage the fd's, as an example: Call close() when you
received a delete event.
- No way to get out of band data.
- 1024 is still too low. ;-)
When you talk about designing a file change notification system that
scales to 1000s of directories, juggling 1000s of fd's just does not seem
the right interface. It is too heavy.
Q: Why the system call approach?
A: The poor user-space interface is the second biggest problem with dnotify.
Signals are a terrible, terrible interface for file notification. Or for
anything, for that matter. The ideal 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 have been done either via a
device file or a family of new system calls. We decided to implement a
family of system calls because that is the preffered approach for new kernel
features and it means our user interface requirements.
Additionally, it _is_ possible to more than one instance and
juggle more than one queue and thus more than one associated fd.

3
arch/i386/kernel/syscall_table.S
View file

@ -291,3 +291,6 @@ ENTRY(sys_call_table)
.long sys_keyctl
.long sys_ioprio_set
.long sys_ioprio_get /* 290 */
.long sys_inotify_init
.long sys_inotify_add_watch
.long sys_inotify_rm_watch

13
fs/Kconfig
View file

@ -359,6 +359,19 @@ config ROMFS_FS
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

1
fs/Makefile
View file

@ -12,6 +12,7 @@ obj-y := open.o read_write.o file_table.o buffer.o bio.o super.o \
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

33
fs/attr.c
View file

@ -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 @@ int inode_setattr(struct inode * inode, struct iattr * attr)
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 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
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;
}

12
fs/compat.c
View file

@ -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 @@ static ssize_t compat_do_readv_writev(int type, struct file *file,
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;
}

3
fs/file_table.c
View file

@ -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 = {
@ -126,6 +127,8 @@ void fastcall __fput(struct file *file)
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.

6
fs/inode.c
View file

@ -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:
@ -202,6 +203,10 @@ void inode_init_once(struct inode *inode)
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);
@ -351,6 +356,7 @@ int invalidate_inodes(struct super_block * sb)
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);

999
fs/inotify.c Normal file
View file

@ -0,0 +1,999 @@
/*
* 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/mount.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 struct vfsmount *inotify_mnt;
/* These are configurable via /proc/sys/inotify */
int inotify_max_user_devices;
int inotify_max_user_watches;
int inotify_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 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;
}
/*
* find_inode - resolve a user-given path to a specific inode and return a nd
*/
static int find_inode(const char __user *dirname, struct nameidata *nd)
{
int error;
error = __user_walk(dirname, LOOKUP_FOLLOW, nd);
if (error)
return error;
/* you can only watch an inode if you have read permissions on it */
error = permission(nd->dentry->d_inode, MAY_READ, NULL);
if (error)
path_release (nd);
return error;
}
/*
* 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) >= inotify_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, *need_iput = NULL;
list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
struct inotify_watch *watch, *next_w;
struct inode *need_iput_tmp;
struct list_head *watches;
/*
* If i_count is zero, the inode cannot have any watches and
* doing an __iget/iput with MS_ACTIVE clear would actually
* evict all inodes with zero i_count from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
if (!atomic_read(&inode->i_count))
continue;
/*
* We cannot __iget() an inode in state I_CLEAR, I_FREEING, or
* I_WILL_FREE which is fine because by that point the inode
* cannot have any associated watches.
*/
if (inode->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))
continue;
need_iput_tmp = need_iput;
need_iput = NULL;
/* In case the remove_watch() drops a reference. */
if (inode != need_iput_tmp)
__iget(inode);
else
need_iput_tmp = NULL;
/* In case the dropping of a reference would nuke next_i. */
if ((&next_i->i_sb_list != list) &&
atomic_read(&next_i->i_count) &&
!(next_i->i_state & (I_CLEAR | I_FREEING |
I_WILL_FREE))) {
__iget(next_i);
need_iput = next_i;
}
/*
* We can safely drop inode_lock here because we hold
* references on both inode and next_i. Also no new inodes
* will be added since the umount has begun. Finally,
* iprune_sem keeps shrink_icache_memory() away.
*/
spin_unlock(&inode_lock);
if (need_iput_tmp)
iput(need_iput_tmp);
/* 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_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;
}
/*
* 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;
void __user *p;
int ret = -ENOTTY;
dev = file->private_data;
p = (void __user *) arg;
switch (cmd) {
case FIONREAD:
ret = put_user(dev->queue_size, (int __user *) p);
break;
}
return ret;
}
static struct file_operations inotify_fops = {
.poll = inotify_poll,
.read = inotify_read,
.release = inotify_release,
.unlocked_ioctl = inotify_ioctl,
.compat_ioctl = inotify_ioctl,
};
asmlinkage long sys_inotify_init(void)
{
struct inotify_device *dev;
struct user_struct *user;
int ret = -ENOTTY;
int fd;
struct file *filp;
fd = get_unused_fd();
if (fd < 0) {
ret = fd;
goto out;
}
filp = get_empty_filp();
if (!filp) {
put_unused_fd(fd);
ret = -ENFILE;
goto out;
}
filp->f_op = &inotify_fops;
filp->f_vfsmnt = mntget(inotify_mnt);
filp->f_dentry = dget(inotify_mnt->mnt_root);
filp->f_mapping = filp->f_dentry->d_inode->i_mapping;
filp->f_mode = FMODE_READ;
filp->f_flags = O_RDONLY;
user = get_uid(current->user);
if (unlikely(atomic_read(&user->inotify_devs) >= inotify_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 = inotify_max_queued_events;
dev->user = user;
atomic_set(&dev->count, 0);
get_inotify_dev(dev);
atomic_inc(&user->inotify_devs);
filp->private_data = dev;
fd_install (fd, filp);
return fd;
out_err:
put_unused_fd (fd);
put_filp (filp);
free_uid(user);
out:
return ret;
}
asmlinkage long sys_inotify_add_watch(int fd, const char *path, u32 mask)
{
struct inotify_watch *watch, *old;
struct inode *inode;
struct inotify_device *dev;
struct nameidata nd;
struct file *filp;
int ret;
filp = fget(fd);
if (!filp)
return -EBADF;
dev = filp->private_data;
ret = find_inode ((const char __user*)path, &nd);
if (ret)
goto fput_and_out;
/* Held in place by reference in nd */
inode = nd.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:
path_release (&nd);
up(&dev->sem);
up(&inode->inotify_sem);
fput_and_out:
fput(filp);
return ret;
}
asmlinkage long sys_inotify_rm_watch(int fd, u32 wd)
{
struct file *filp;
struct inotify_device *dev;
int ret;
filp = fget(fd);
if (!filp)
return -EBADF;
dev = filp->private_data;
ret = inotify_ignore (dev, wd);
fput(filp);
return ret;
}
static struct super_block *
inotify_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
{
return get_sb_pseudo(fs_type, "inotify", NULL, 0xBAD1DEA);
}
static struct file_system_type inotify_fs_type = {
.name = "inotifyfs",
.get_sb = inotify_get_sb,
.kill_sb = kill_anon_super,
};
/*
* 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)
{
register_filesystem(&inotify_fs_type);
inotify_mnt = kern_mount(&inotify_fs_type);
inotify_max_queued_events = 8192;
inotify_max_user_devices = 128;
inotify_max_user_watches = 8192;
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 syscall\n");
return 0;
}
module_init(inotify_init);

30
fs/namei.c
View file

@ -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>
@ -1312,7 +1312,7 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
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;
@ -1637,7 +1637,7 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
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;
@ -1710,7 +1710,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
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;
@ -1801,7 +1801,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry)
}
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);
@ -1874,9 +1874,10 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
/* 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;
}
@ -1950,7 +1951,7 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname, i
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;
@ -2023,7 +2024,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
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;
@ -2187,6 +2188,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
{
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;
@ -2208,18 +2210,18 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
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;
}

6
fs/nfsd/vfs.c
View file

@ -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>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#ifdef CONFIG_NFSD_V4
@ -860,7 +860,7 @@ nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
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:
@ -916,7 +916,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
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 */

3
fs/open.c
View file

@ -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>
@ -951,6 +951,7 @@ asmlinkage long sys_open(const char __user * filename, int flags, int mode)
put_unused_fd(fd);
fd = PTR_ERR(f);
} else {
fsnotify_open(f->f_dentry);
fd_install(fd, f);
}
}

15
fs/read_write.c
View file

@ -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>
@ -252,7 +252,7 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
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++;
@ -303,7 +303,7 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
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++;
@ -539,9 +539,12 @@ static ssize_t do_readv_writev(int type, struct file *file,
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;

7
fs/sysfs/file.c
View file

@ -3,7 +3,7 @@
*/
#include <linux/module.h>
#include <linux/dnotify.h>
#include <linux/fsnotify.h>
#include <linux/kobject.h>
#include <linux/namei.h>
#include <asm/uaccess.h>
@ -391,9 +391,6 @@ int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
* 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)
{
@ -408,7 +405,7 @@ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
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().

5
fs/xattr.c
View file

@ -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 @@ setxattr(struct dentry *d, char __user *name, void __user *value,
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);
}

5
include/asm-i386/unistd.h
View file

@ -296,8 +296,11 @@
#define __NR_keyctl 288
#define __NR_ioprio_set 289
#define __NR_ioprio_get 290
#define __NR_inotify_init 291
#define __NR_inotify_add_watch 292
#define __NR_inotify_rm_watch 293
#define NR_syscalls 291
#define NR_syscalls 294
/*
* user-visible error numbers are in the range -1 - -128: see

6
include/linux/fs.h
View file

@ -474,6 +474,11 @@ struct inode {
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 */
@ -1393,7 +1398,6 @@ extern void emergency_remount(void);
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,

248
include/linux/fsnotify.h Normal file
View file

@ -0,0 +1,248 @@
#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
*/
static inline const char *fsnotify_oldname_init(const char *name)
{
return kstrdup(name, GFP_KERNEL);
}
/*
* 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 */

108
include/linux/inotify.h Normal file
View file

@ -0,0 +1,108 @@
/*
* 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 */
};
/* 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)
#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 */

4
include/linux/sched.h
View file

@ -410,6 +410,10 @@ struct user_struct {
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 ? */

11
include/linux/sysctl.h
View file

@ -61,7 +61,8 @@ enum
CTL_DEV=7, /* Devices */
CTL_BUS=8, /* Busses */
CTL_ABI=9, /* Binary emulation */
CTL_CPU=10 /* CPU stuff (speed scaling, etc) */
CTL_CPU=10, /* CPU stuff (speed scaling, etc) */
CTL_INOTIFY=11 /* Inotify */
};
/* CTL_BUS names: */
@ -70,6 +71,14 @@ enum
CTL_BUS_ISA=1 /* ISA */
};
/* CTL_INOTIFY names: */
enum
{
INOTIFY_MAX_USER_DEVICES=1, /* max number of inotify device instances per user */
INOTIFY_MAX_USER_WATCHES=2, /* max number of inotify watches per user */
INOTIFY_MAX_QUEUED_EVENTS=3 /* Max number of queued events per inotify device instance */
};
/* CTL_KERN names: */
enum
{

3
kernel/sys_ni.c
View file

@ -80,6 +80,9 @@ cond_syscall(sys_keyctl);
cond_syscall(compat_sys_keyctl);
cond_syscall(compat_sys_socketcall);
cond_syscall(sys_set_zone_reclaim);
cond_syscall(sys_inotify_init);
cond_syscall(sys_inotify_add_watch);
cond_syscall(sys_inotify_rm_watch);
/* arch-specific weak syscall entries */
cond_syscall(sys_pciconfig_read);

43
kernel/sysctl.c
View file

@ -67,6 +67,12 @@ extern int printk_ratelimit_jiffies;
extern int printk_ratelimit_burst;
extern int pid_max_min, pid_max_max;
#ifdef CONFIG_INOTIFY
extern int inotify_max_user_devices;
extern int inotify_max_user_watches;
extern int inotify_max_queued_events;
#endif
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
int unknown_nmi_panic;
extern int proc_unknown_nmi_panic(ctl_table *, int, struct file *,
@ -218,6 +224,7 @@ static ctl_table root_table[] = {
.mode = 0555,
.child = dev_table,
},
{ .ctl_name = 0 }
};
@ -959,6 +966,40 @@ static ctl_table fs_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
#ifdef CONFIG_INOTIFY
{
.ctl_name = INOTIFY_MAX_USER_DEVICES,
.procname = "max_user_devices",
.data = &inotify_max_user_devices,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
{
.ctl_name = INOTIFY_MAX_USER_WATCHES,
.procname = "max_user_watches",
.data = &inotify_max_user_watches,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
{
.ctl_name = INOTIFY_MAX_QUEUED_EVENTS,
.procname = "max_queued_events",
.data = &inotify_max_queued_events,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &zero
},
#endif
{ .ctl_name = 0 }
};
@ -968,7 +1009,7 @@ static ctl_table debug_table[] = {
static ctl_table dev_table[] = {
{ .ctl_name = 0 }
};
};
extern void init_irq_proc (void);

4
kernel/user.c
View file

@ -120,6 +120,10 @@ struct user_struct * alloc_uid(uid_t uid)
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;