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
  28 unsigned 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
  48 unsigned 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 }