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 "udf_sb.h"
27
28 unsigned int udf_get_last_session(struct super_block *sb)
29 {
30 struct cdrom_multisession ms_info;
31 unsigned int vol_desc_start;
32 struct block_device *bdev = sb->s_bdev;
33 int i;
34
35 vol_desc_start = 0;
36 ms_info.addr_format = CDROM_LBA;
37 i = ioctl_by_bdev(bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
38
39 #define WE_OBEY_THE_WRITTEN_STANDARDS 1
40
41 if (i == 0) {
42 udf_debug("XA disk: %s, vol_desc_start=%d\n",
43 (ms_info.xa_flag ? "yes" : "no"), ms_info.addr.lba);
44 #if WE_OBEY_THE_WRITTEN_STANDARDS
45 if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
46 #endif
47 vol_desc_start = ms_info.addr.lba;
48 } else {
49 udf_debug("CDROMMULTISESSION not supported: rc=%d\n", i);
50 }
51 return vol_desc_start;
52 }
53
54 unsigned long udf_get_last_block(struct super_block *sb)
55 {
56 struct block_device *bdev = sb->s_bdev;
57 unsigned long lblock = 0;
58
59 /*
60 * ioctl failed or returned obviously bogus value?
61 * Try using the device size...
62 */
63 if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock) ||
64 lblock == 0)
65 lblock = bdev->bd_inode->i_size >> sb->s_blocksize_bits;
66
67 if (lblock)
68 return lblock - 1;
69 else
70 return 0;
71 }
72
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