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 <linux/uaccess.h>
  25
  26#include "udf_sb.h"
  27
  28unsigned int udf_get_last_session(struct super_block *sb)
  29{
  30        struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
  31        struct cdrom_multisession ms_info;
  32
  33        if (!cdi) {
  34                udf_debug("CDROMMULTISESSION not supported.\n");
  35                return 0;
  36        }
  37
  38        ms_info.addr_format = CDROM_LBA;
  39        if (cdrom_multisession(cdi, &ms_info) == 0) {
  40                udf_debug("XA disk: %s, vol_desc_start=%d\n",
  41                          ms_info.xa_flag ? "yes" : "no", ms_info.addr.lba);
  42                if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
  43                        return ms_info.addr.lba;
  44        }
  45        return 0;
  46}
  47
  48unsigned long udf_get_last_block(struct super_block *sb)
  49{
  50        struct block_device *bdev = sb->s_bdev;
  51        struct cdrom_device_info *cdi = disk_to_cdi(bdev->bd_disk);
  52        unsigned long lblock = 0;
  53
  54        /*
  55         * The cdrom layer call failed or returned obviously bogus value?
  56         * Try using the device size...
  57         */
  58        if (!cdi || cdrom_get_last_written(cdi, &lblock) || lblock == 0)
  59                lblock = i_size_read(bdev->bd_inode) >> sb->s_blocksize_bits;
  60
  61        if (lblock)
  62                return lblock - 1;
  63        return 0;
  64}
  65