Root/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 "udf_sb.h"
27
28unsigned 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    if (i == 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            vol_desc_start = ms_info.addr.lba;
44    } else {
45        udf_debug("CDROMMULTISESSION not supported: rc=%d\n", i);
46    }
47    return vol_desc_start;
48}
49
50unsigned long udf_get_last_block(struct super_block *sb)
51{
52    struct block_device *bdev = sb->s_bdev;
53    unsigned long lblock = 0;
54
55    /*
56     * ioctl failed or returned obviously bogus value?
57     * Try using the device size...
58     */
59    if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock) ||
60        lblock == 0)
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}
68

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