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 
udf_get_last_session(struct super_block * sb)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 
udf_get_last_block(struct super_block * sb)48 udf_pblk_t udf_get_last_block(struct super_block *sb)
49 {
50 	struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
51 	unsigned long lblock = 0;
52 
53 	/*
54 	 * The cdrom layer call failed or returned obviously bogus value?
55 	 * Try using the device size...
56 	 */
57 	if (!cdi || cdrom_get_last_written(cdi, &lblock) || lblock == 0) {
58 		if (sb_bdev_nr_blocks(sb) > ~(udf_pblk_t)0)
59 			return 0;
60 		lblock = sb_bdev_nr_blocks(sb);
61 	}
62 
63 	if (lblock)
64 		return lblock - 1;
65 	return 0;
66 }
67