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This is the code that computes crc32 and ecc for ocfs2 metadata blocks. There are high-level functions that check whether the filesystem has the ecc feature, mid-level functions that work on a single block or array of buffer_heads, and the low-level ecc hamming code that can handle multiple buffers like crc32_le(). It's not hooked up to the filesystem yet. Signed-off-by: Joel Becker <joel.becker@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
82 lines
2.9 KiB
C
82 lines
2.9 KiB
C
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* blockcheck.h
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*
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* Checksum and ECC codes for the OCFS2 userspace library.
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*
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* Copyright (C) 2004, 2008 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License, version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#ifndef OCFS2_BLOCKCHECK_H
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#define OCFS2_BLOCKCHECK_H
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/* High level block API */
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void ocfs2_compute_meta_ecc(struct super_block *sb, void *data,
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struct ocfs2_block_check *bc);
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int ocfs2_validate_meta_ecc(struct super_block *sb, void *data,
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struct ocfs2_block_check *bc);
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void ocfs2_compute_meta_ecc_bhs(struct super_block *sb,
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struct buffer_head **bhs, int nr,
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struct ocfs2_block_check *bc);
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int ocfs2_validate_meta_ecc_bhs(struct super_block *sb,
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struct buffer_head **bhs, int nr,
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struct ocfs2_block_check *bc);
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/* Lower level API */
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void ocfs2_block_check_compute(void *data, size_t blocksize,
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struct ocfs2_block_check *bc);
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int ocfs2_block_check_validate(void *data, size_t blocksize,
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struct ocfs2_block_check *bc);
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void ocfs2_block_check_compute_bhs(struct buffer_head **bhs, int nr,
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struct ocfs2_block_check *bc);
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int ocfs2_block_check_validate_bhs(struct buffer_head **bhs, int nr,
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struct ocfs2_block_check *bc);
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/*
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* Hamming code functions
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*/
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/*
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* Encoding hamming code parity bits for a buffer.
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*
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* This is the low level encoder function. It can be called across
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* multiple hunks just like the crc32 code. 'd' is the number of bits
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* _in_this_hunk_. nr is the bit offset of this hunk. So, if you had
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* two 512B buffers, you would do it like so:
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*
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* parity = ocfs2_hamming_encode(0, buf1, 512 * 8, 0);
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* parity = ocfs2_hamming_encode(parity, buf2, 512 * 8, 512 * 8);
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*
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* If you just have one buffer, use ocfs2_hamming_encode_block().
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*/
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u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d,
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unsigned int nr);
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/*
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* Fix a buffer with a bit error. The 'fix' is the original parity
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* xor'd with the parity calculated now.
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*
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* Like ocfs2_hamming_encode(), this can handle hunks. nr is the bit
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* offset of the current hunk. If bit to be fixed is not part of the
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* current hunk, this does nothing.
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*
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* If you only have one buffer, use ocfs2_hamming_fix_block().
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*/
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void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr,
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unsigned int fix);
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/* Convenience wrappers for a single buffer of data */
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extern u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize);
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extern void ocfs2_hamming_fix_block(void *data, unsigned int blocksize,
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unsigned int fix);
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#endif
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