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[PATCH] inotify

Browse source 
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 <[email protected]>
Cc: John McCutchan <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Robert Love 2005-07-12 17:06:03 -04:00 • committed by Linus Torvalds
commit 0eeca28300
24 changed files with 1639 additions and 67 deletions
Download patch file Download diff file Expand all files Collapse all files

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);
}