LXR linux/fs/udf/lowlevel.c

   1/*
   2 * lowlevel.c
   3 *
   4 * PURPOSE
   5 *  Low Level Device Routines for the UDF filesystem
   6 *
   7 * COPYRIGHT
   8 *      This file is distributed under the terms of the GNU General Public
   9 *      License (GPL). Copies of the GPL can be obtained from:
  10 *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  11 *      Each contributing author retains all rights to their own work.
  12 *
  13 *  (C) 1999-2001 Ben Fennema
  14 *
  15 * HISTORY
  16 *
  17 *  03/26/99 blf  Created.
  18 */
  19
  20#include "udfdecl.h"
  21
  22#include <linux/blkdev.h>
  23#include <linux/cdrom.h>
  24#include <asm/uaccess.h>
  25
  26#include <linux/udf_fs.h>
  27#include "udf_sb.h"
  28
  29unsigned int udf_get_last_session(struct super_block *sb)
  30{
  31        struct cdrom_multisession ms_info;
  32        unsigned int vol_desc_start;
  33        struct block_device *bdev = sb->s_bdev;
  34        int i;
  35
  36        vol_desc_start = 0;
  37        ms_info.addr_format = CDROM_LBA;
  38        i = ioctl_by_bdev(bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
  39
  40#define WE_OBEY_THE_WRITTEN_STANDARDS 1
  41
  42        if (i == 0) {
  43                udf_debug("XA disk: %s, vol_desc_start=%d\n",
  44                          (ms_info.xa_flag ? "yes" : "no"), ms_info.addr.lba);
  45#if WE_OBEY_THE_WRITTEN_STANDARDS
  46                if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
  47#endif
  48                        vol_desc_start = ms_info.addr.lba;
  49        } else {
  50                udf_debug("CDROMMULTISESSION not supported: rc=%d\n", i);
  51        }
  52        return vol_desc_start;
  53}
  54
  55unsigned long udf_get_last_block(struct super_block *sb)
  56{
  57        struct block_device *bdev = sb->s_bdev;
  58        unsigned long lblock = 0;
  59
  60        if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock))
  61                lblock = bdev->bd_inode->i_size >> sb->s_blocksize_bits;
  62
  63        if (lblock)
  64                return lblock - 1;
  65        else
  66                return 0;
  67}
  68