linux/fs/dnotify.c
Josef "Jeff" Sipek 0f7fc9e4d0 [PATCH] VFS: change struct file to use struct path
This patch changes struct file to use struct path instead of having
independent pointers to struct dentry and struct vfsmount, and converts all
users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}.

Additionally, it adds two #define's to make the transition easier for users of
the f_dentry and f_vfsmnt.

Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:41 -08:00

183 lines
4.3 KiB
C

/*
* Directory notifications for Linux.
*
* Copyright (C) 2000,2001,2002 Stephen Rothwell
*
* 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/fs.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/dnotify.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
int dir_notify_enable __read_mostly = 1;
static struct kmem_cache *dn_cache __read_mostly;
static void redo_inode_mask(struct inode *inode)
{
unsigned long new_mask;
struct dnotify_struct *dn;
new_mask = 0;
for (dn = inode->i_dnotify; dn != NULL; dn = dn->dn_next)
new_mask |= dn->dn_mask & ~DN_MULTISHOT;
inode->i_dnotify_mask = new_mask;
}
void dnotify_flush(struct file *filp, fl_owner_t id)
{
struct dnotify_struct *dn;
struct dnotify_struct **prev;
struct inode *inode;
inode = filp->f_path.dentry->d_inode;
if (!S_ISDIR(inode->i_mode))
return;
spin_lock(&inode->i_lock);
prev = &inode->i_dnotify;
while ((dn = *prev) != NULL) {
if ((dn->dn_owner == id) && (dn->dn_filp == filp)) {
*prev = dn->dn_next;
redo_inode_mask(inode);
kmem_cache_free(dn_cache, dn);
break;
}
prev = &dn->dn_next;
}
spin_unlock(&inode->i_lock);
}
int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
{
struct dnotify_struct *dn;
struct dnotify_struct *odn;
struct dnotify_struct **prev;
struct inode *inode;
fl_owner_t id = current->files;
int error = 0;
if ((arg & ~DN_MULTISHOT) == 0) {
dnotify_flush(filp, id);
return 0;
}
if (!dir_notify_enable)
return -EINVAL;
inode = filp->f_path.dentry->d_inode;
if (!S_ISDIR(inode->i_mode))
return -ENOTDIR;
dn = kmem_cache_alloc(dn_cache, GFP_KERNEL);
if (dn == NULL)
return -ENOMEM;
spin_lock(&inode->i_lock);
prev = &inode->i_dnotify;
while ((odn = *prev) != NULL) {
if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
odn->dn_fd = fd;
odn->dn_mask |= arg;
inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
goto out_free;
}
prev = &odn->dn_next;
}
error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
if (error)
goto out_free;
dn->dn_mask = arg;
dn->dn_fd = fd;
dn->dn_filp = filp;
dn->dn_owner = id;
inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
dn->dn_next = inode->i_dnotify;
inode->i_dnotify = dn;
spin_unlock(&inode->i_lock);
if (filp->f_op && filp->f_op->dir_notify)
return filp->f_op->dir_notify(filp, arg);
return 0;
out_free:
spin_unlock(&inode->i_lock);
kmem_cache_free(dn_cache, dn);
return error;
}
void __inode_dir_notify(struct inode *inode, unsigned long event)
{
struct dnotify_struct * dn;
struct dnotify_struct **prev;
struct fown_struct * fown;
int changed = 0;
spin_lock(&inode->i_lock);
prev = &inode->i_dnotify;
while ((dn = *prev) != NULL) {
if ((dn->dn_mask & event) == 0) {
prev = &dn->dn_next;
continue;
}
fown = &dn->dn_filp->f_owner;
send_sigio(fown, dn->dn_fd, POLL_MSG);
if (dn->dn_mask & DN_MULTISHOT)
prev = &dn->dn_next;
else {
*prev = dn->dn_next;
changed = 1;
kmem_cache_free(dn_cache, dn);
}
}
if (changed)
redo_inode_mask(inode);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(__inode_dir_notify);
/*
* This is hopelessly wrong, but unfixable without API changes. At
* least it doesn't oops the kernel...
*
* To safely access ->d_parent we need to keep d_move away from it. Use the
* dentry's d_lock for this.
*/
void dnotify_parent(struct dentry *dentry, unsigned long event)
{
struct dentry *parent;
if (!dir_notify_enable)
return;
spin_lock(&dentry->d_lock);
parent = dentry->d_parent;
if (parent->d_inode->i_dnotify_mask & event) {
dget(parent);
spin_unlock(&dentry->d_lock);
__inode_dir_notify(parent->d_inode, event);
dput(parent);
} else {
spin_unlock(&dentry->d_lock);
}
}
EXPORT_SYMBOL_GPL(dnotify_parent);
static int __init dnotify_init(void)
{
dn_cache = kmem_cache_create("dnotify_cache",
sizeof(struct dnotify_struct), 0, SLAB_PANIC, NULL, NULL);
return 0;
}
module_init(dnotify_init)