fs/udf/lowlevel.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * lowlevel.c
   4  *
   5  * PURPOSE
   6  *  Low Level Device Routines for the UDF filesystem
   7  *
   8  * COPYRIGHT
   9  *  (C) 1999-2001 Ben Fennema
  10  *
  11  * HISTORY
  12  *
  13  *  03/26/99 blf  Created.
  14  */
  15
  16 #include "udfdecl.h"
  17
  18 #include <linux/blkdev.h>
  19 #include <linux/cdrom.h>
  20 #include <linux/uaccess.h>
  21
  22 #include "udf_sb.h"
  23
  24 unsigned int udf_get_last_session(struct super_block *sb)
  25 {
  26         struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
  27         struct cdrom_multisession ms_info;
  28
  29         if (!cdi) {
  30                 udf_debug("CDROMMULTISESSION not supported.\n");
  31                 return 0;
  32         }
  33
  34         ms_info.addr_format = CDROM_LBA;
  35         if (cdrom_multisession(cdi, &ms_info) == 0) {
  36                 udf_debug("XA disk: %s, vol_desc_start=%d\n",
  37                           ms_info.xa_flag ? "yes" : "no", ms_info.addr.lba);
  38                 if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
  39                         return ms_info.addr.lba;
  40         }
  41         return 0;
  42 }
  43
  44 udf_pblk_t udf_get_last_block(struct super_block *sb)
  45 {
  46         struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
  47         unsigned long lblock = 0;
  48
  49         /*
  50          * The cdrom layer call failed or returned obviously bogus value?
  51          * Try using the device size...
  52          */
  53         if (!cdi || cdrom_get_last_written(cdi, &lblock) || lblock == 0) {
  54                 if (sb_bdev_nr_blocks(sb) > ~(udf_pblk_t)0)
  55                         return 0;
  56                 lblock = sb_bdev_nr_blocks(sb);
  57         }
  58
  59         if (lblock)
  60                 return lblock - 1;
  61         return 0;
  62 }