/*
   * 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
  ",
  			  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
  ", 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;
  }