fs/udf/lowlevel.c

   1 /*
   2  * lowlevel.c
   3  *
   4  * PURPOSE
   5  *  Low Level Device Routines for the UDF filesystem
   6  *
   7  * CONTACTS
   8  *      E-mail regarding any portion of the Linux UDF file system should be
   9  *      directed to the development team mailing list (run by majordomo):
  10  *              linux_udf@hpesjro.fc.hp.com
  11  *
  12  * COPYRIGHT
  13  *      This file is distributed under the terms of the GNU General Public
  14  *      License (GPL). Copies of the GPL can be obtained from:
  15  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  16  *      Each contributing author retains all rights to their own work.
  17  *
  18  *  (C) 1999-2001 Ben Fennema
  19  *
  20  * HISTORY
  21  *
  22  *  03/26/99 blf  Created.
  23  */
  24
  25 #include "udfdecl.h"
  26
  27 #include <linux/blkdev.h>
  28 #include <linux/cdrom.h>
  29 #include <asm/uaccess.h>
  30
  31 #include <linux/udf_fs.h>
  32 #include "udf_sb.h"
  33
  34 unsigned int
  35 udf_get_last_session(struct super_block *sb)
  36 {
  37         struct cdrom_multisession ms_info;
  38         unsigned int vol_desc_start;
  39         struct block_device *bdev = sb->s_bdev;
  40         int i;
  41
  42         vol_desc_start=0;
  43         ms_info.addr_format=CDROM_LBA;
  44         i = ioctl_by_bdev(bdev, CDROMMULTISESSION, (unsigned long) &ms_info);
  45
  46 #define WE_OBEY_THE_WRITTEN_STANDARDS 1
  47
  48         if (i == 0)
  49         {
  50                 udf_debug("XA disk: %s, vol_desc_start=%d\n",
  51                         (ms_info.xa_flag ? "yes" : "no"), ms_info.addr.lba);
  52 #if WE_OBEY_THE_WRITTEN_STANDARDS
  53                 if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
  54 #endif
  55                         vol_desc_start = ms_info.addr.lba;
  56         }
  57         else
  58         {
  59                 udf_debug("CDROMMULTISESSION not supported: rc=%d\n", i);
  60         }
  61         return vol_desc_start;
  62 }
  63
  64 unsigned long
  65 udf_get_last_block(struct super_block *sb)
  66 {
  67         struct block_device *bdev = sb->s_bdev;
  68         unsigned long lblock = 0;
  69
  70         if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock))
  71                 lblock = bdev->bd_inode->i_size >> sb->s_blocksize_bits;
  72
  73         if (lblock)
  74                 return lblock - 1;
  75         else
  76                 return 0;
  77 }