Revision 016e8d44bc06dd3322f26712bdd3f3a6973592d0 authored by Josh Boyer on 19 August 2011, 18:50:26 UTC, committed by Al Viro on 19 November 2011, 16:13:26 UTC
Newer versions of MINIX can create filesystems that allocate an extra bitmap block. Mounting of this succeeds, but doing a statfs call will result in an oops in count_free because of a negative number being used for the bh index. Avoid this by verifying the number of allocated blocks at mount time, erroring out if there are not enough and make statfs ignore the extras if there are too many. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=18792 Signed-off-by: Josh Boyer <jwboyer@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1 parent d633180
phonedev.c
/*
* Telephony registration for Linux
*
* (c) Copyright 1999 Red Hat Software Inc.
*
* 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 of the License, or (at your option) any later version.
*
* Author: Alan Cox, <alan@lxorguk.ukuu.org.uk>
*
* Fixes: Mar 01 2000 Thomas Sparr, <thomas.l.sparr@telia.com>
* phone_register_device now works with unit!=PHONE_UNIT_ANY
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/phonedev.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/kmod.h>
#include <linux/sem.h>
#include <linux/mutex.h>
#define PHONE_NUM_DEVICES 256
/*
* Active devices
*/
static struct phone_device *phone_device[PHONE_NUM_DEVICES];
static DEFINE_MUTEX(phone_lock);
/*
* Open a phone device.
*/
static int phone_open(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
int err = 0;
struct phone_device *p;
const struct file_operations *old_fops, *new_fops = NULL;
if (minor >= PHONE_NUM_DEVICES)
return -ENODEV;
mutex_lock(&phone_lock);
p = phone_device[minor];
if (p)
new_fops = fops_get(p->f_op);
if (!new_fops) {
mutex_unlock(&phone_lock);
request_module("char-major-%d-%d", PHONE_MAJOR, minor);
mutex_lock(&phone_lock);
p = phone_device[minor];
if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL)
{
err=-ENODEV;
goto end;
}
}
old_fops = file->f_op;
file->f_op = new_fops;
if (p->open)
err = p->open(p, file); /* Tell the device it is open */
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
end:
mutex_unlock(&phone_lock);
return err;
}
/*
* Telephony For Linux device drivers request registration here.
*/
int phone_register_device(struct phone_device *p, int unit)
{
int base;
int end;
int i;
base = 0;
end = PHONE_NUM_DEVICES - 1;
if (unit != PHONE_UNIT_ANY) {
base = unit;
end = unit + 1; /* enter the loop at least one time */
}
mutex_lock(&phone_lock);
for (i = base; i < end; i++) {
if (phone_device[i] == NULL) {
phone_device[i] = p;
p->minor = i;
mutex_unlock(&phone_lock);
return 0;
}
}
mutex_unlock(&phone_lock);
return -ENFILE;
}
/*
* Unregister an unused Telephony for linux device
*/
void phone_unregister_device(struct phone_device *pfd)
{
mutex_lock(&phone_lock);
if (likely(phone_device[pfd->minor] == pfd))
phone_device[pfd->minor] = NULL;
mutex_unlock(&phone_lock);
}
static const struct file_operations phone_fops =
{
.owner = THIS_MODULE,
.open = phone_open,
.llseek = noop_llseek,
};
/*
* Board init functions
*/
/*
* Initialise Telephony for linux
*/
static int __init telephony_init(void)
{
printk(KERN_INFO "Linux telephony interface: v1.00\n");
if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) {
printk("phonedev: unable to get major %d\n", PHONE_MAJOR);
return -EIO;
}
return 0;
}
static void __exit telephony_exit(void)
{
unregister_chrdev(PHONE_MAJOR, "telephony");
}
module_init(telephony_init);
module_exit(telephony_exit);
MODULE_LICENSE("GPL");
EXPORT_SYMBOL(phone_register_device);
EXPORT_SYMBOL(phone_unregister_device);
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