68 строки
1.6 KiB
C
68 строки
1.6 KiB
C
/*
|
|
* lowlevel.c
|
|
*
|
|
* PURPOSE
|
|
* Low Level Device Routines for the UDF filesystem
|
|
*
|
|
* COPYRIGHT
|
|
* This file is distributed under the terms of the GNU General Public
|
|
* License (GPL). Copies of the GPL can be obtained from:
|
|
* ftp://prep.ai.mit.edu/pub/gnu/GPL
|
|
* Each contributing author retains all rights to their own work.
|
|
*
|
|
* (C) 1999-2001 Ben Fennema
|
|
*
|
|
* HISTORY
|
|
*
|
|
* 03/26/99 blf Created.
|
|
*/
|
|
|
|
#include "udfdecl.h"
|
|
|
|
#include <linux/blkdev.h>
|
|
#include <linux/cdrom.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#include "udf_sb.h"
|
|
|
|
unsigned int udf_get_last_session(struct super_block *sb)
|
|
{
|
|
struct cdrom_multisession ms_info;
|
|
unsigned int vol_desc_start;
|
|
struct block_device *bdev = sb->s_bdev;
|
|
int i;
|
|
|
|
vol_desc_start = 0;
|
|
ms_info.addr_format = CDROM_LBA;
|
|
i = ioctl_by_bdev(bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
|
|
|
|
if (i == 0) {
|
|
udf_debug("XA disk: %s, vol_desc_start=%d\n",
|
|
ms_info.xa_flag ? "yes" : "no", ms_info.addr.lba);
|
|
if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
|
|
vol_desc_start = ms_info.addr.lba;
|
|
} else {
|
|
udf_debug("CDROMMULTISESSION not supported: rc=%d\n", i);
|
|
}
|
|
return vol_desc_start;
|
|
}
|
|
|
|
unsigned long udf_get_last_block(struct super_block *sb)
|
|
{
|
|
struct block_device *bdev = sb->s_bdev;
|
|
unsigned long lblock = 0;
|
|
|
|
/*
|
|
* ioctl failed or returned obviously bogus value?
|
|
* Try using the device size...
|
|
*/
|
|
if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock) ||
|
|
lblock == 0)
|
|
lblock = i_size_read(bdev->bd_inode) >> sb->s_blocksize_bits;
|
|
|
|
if (lblock)
|
|
return lblock - 1;
|
|
else
|
|
return 0;
|
|
}
|