io.c 1.38 KB
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// SPDX-License-Identifier: GPL-2.0
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/*
 * linux/fs/befs/io.c
 *
 * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
 *
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 * Based on portions of file.c and inode.c
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 * by Makoto Kato (m_kato@ga2.so-net.ne.jp)
 *
 * Many thanks to Dominic Giampaolo, author of Practical File System
 * Design with the Be File System, for such a helpful book.
 *
 */

#include <linux/buffer_head.h>

#include "befs.h"
#include "io.h"

/*
 * Converts befs notion of disk addr to a disk offset and uses
 * linux kernel function sb_bread() to get the buffer containing
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 * the offset.
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 */

struct buffer_head *
befs_bread_iaddr(struct super_block *sb, befs_inode_addr iaddr)
{
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	struct buffer_head *bh;
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	befs_blocknr_t block;
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	struct befs_sb_info *befs_sb = BEFS_SB(sb);
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	befs_debug(sb, "---> Enter %s "
		   "[%u, %hu, %hu]", __func__, iaddr.allocation_group,
		   iaddr.start, iaddr.len);
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	if (iaddr.allocation_group > befs_sb->num_ags) {
		befs_error(sb, "BEFS: Invalid allocation group %u, max is %u",
			   iaddr.allocation_group, befs_sb->num_ags);
		goto error;
	}

	block = iaddr2blockno(sb, &iaddr);

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	befs_debug(sb, "%s: offset = %lu", __func__, (unsigned long)block);
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	bh = sb_bread(sb, block);

	if (bh == NULL) {
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		befs_error(sb, "Failed to read block %lu",
			   (unsigned long)block);
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		goto error;
	}

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	befs_debug(sb, "<--- %s", __func__);
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	return bh;

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error:
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	befs_debug(sb, "<--- %s ERROR", __func__);
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	return NULL;
}