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
  29 unsigned 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
  55 unsigned 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 }