68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
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/*
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* lowlevel.c
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*
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* PURPOSE
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* Low Level Device Routines for the UDF filesystem
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*
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* COPYRIGHT
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* This file is distributed under the terms of the GNU General Public
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* License (GPL). Copies of the GPL can be obtained from:
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* ftp://prep.ai.mit.edu/pub/gnu/GPL
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* Each contributing author retains all rights to their own work.
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*
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* (C) 1999-2001 Ben Fennema
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*
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* HISTORY
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*
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* 03/26/99 blf Created.
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*/
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#include "udfdecl.h"
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#include <linux/blkdev.h>
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#include <linux/cdrom.h>
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#include <linux/uaccess.h>
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#include "udf_sb.h"
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unsigned int udf_get_last_session(struct super_block *sb)
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{
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struct cdrom_multisession ms_info;
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unsigned int vol_desc_start;
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struct block_device *bdev = sb->s_bdev;
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int i;
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vol_desc_start = 0;
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ms_info.addr_format = CDROM_LBA;
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i = ioctl_by_bdev(bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
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if (i == 0) {
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udf_debug("XA disk: %s, vol_desc_start=%d\n",
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ms_info.xa_flag ? "yes" : "no", ms_info.addr.lba);
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if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
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vol_desc_start = ms_info.addr.lba;
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} else {
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udf_debug("CDROMMULTISESSION not supported: rc=%d\n", i);
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}
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return vol_desc_start;
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}
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unsigned long udf_get_last_block(struct super_block *sb)
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{
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struct block_device *bdev = sb->s_bdev;
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unsigned long lblock = 0;
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/*
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* ioctl failed or returned obviously bogus value?
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* Try using the device size...
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*/
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if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock) ||
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lblock == 0)
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lblock = i_size_read(bdev->bd_inode) >> sb->s_blocksize_bits;
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if (lblock)
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return lblock - 1;
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else
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return 0;
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}
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