/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* blockcheck.h
*
* Checksum and ECC codes for the OCFS2 userspace library.
*
* Copyright (C) 2004, 2008 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License, version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#ifndef OCFS2_BLOCKCHECK_H
#define OCFS2_BLOCKCHECK_H
/* Count errors and error correction from blockcheck.c */
struct ocfs2_blockcheck_stats {
spinlock_t b_lock;
u64 b_check_count; /* Number of blocks we've checked */
u64 b_failure_count; /* Number of failed checksums */
u64 b_recover_count; /* Number of blocks fixed by ecc */
/*
* debugfs entries, used if this is passed to
* ocfs2_blockcheck_stats_debugfs_install()
*/
struct dentry *b_debug_dir; /* Parent of the debugfs files */
struct dentry *b_debug_check; /* Exposes b_check_count */
struct dentry *b_debug_failure; /* Exposes b_failure_count */
struct dentry *b_debug_recover; /* Exposes b_recover_count */
};
/* High level block API */
void ocfs2_compute_meta_ecc(struct super_block *sb, void *data,
struct ocfs2_block_check *bc);
int ocfs2_validate_meta_ecc(struct super_block *sb, void *data,
struct ocfs2_block_check *bc);
void ocfs2_compute_meta_ecc_bhs(struct super_block *sb,
struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc);
int ocfs2_validate_meta_ecc_bhs(struct super_block *sb,
struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc);
/* Lower level API */
void ocfs2_block_check_compute(void *data, size_t blocksize,
struct ocfs2_block_check *bc);
int ocfs2_block_check_validate(void *data, size_t blocksize,
struct ocfs2_block_check *bc,
struct ocfs2_blockcheck_stats *stats);
void ocfs2_block_check_compute_bhs(struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc);
int ocfs2_block_check_validate_bhs(struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc,
struct ocfs2_blockcheck_stats *stats);
/* Debug Initialization */
int ocfs2_blockcheck_stats_debugfs_install(struct ocfs2_blockcheck_stats *stats,
struct dentry *parent);
void ocfs2_blockcheck_stats_debugfs_remove(struct ocfs2_blockcheck_stats *stats);
/*
* Hamming code functions
*/
/*
* Encoding hamming code parity bits for a buffer.
*
* This is the low level encoder function. It can be called across
* multiple hunks just like the crc32 code. 'd' is the number of bits
* _in_this_hunk_. nr is the bit offset of this hunk. So, if you had
* two 512B buffers, you would do it like so:
*
* parity = ocfs2_hamming_encode(0, buf1, 512 * 8, 0);
* parity = ocfs2_hamming_encode(parity, buf2, 512 * 8, 512 * 8);
*
* If you just have one buffer, use ocfs2_hamming_encode_block().
*/
u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d,
unsigned int nr);
/*
* Fix a buffer with a bit error. The 'fix' is the original parity
* xor'd with the parity calculated now.
*
* Like ocfs2_hamming_encode(), this can handle hunks. nr is the bit
* offset of the current hunk. If bit to be fixed is not part of the
* current hunk, this does nothing.
*
* If you only have one buffer, use ocfs2_hamming_fix_block().
*/
void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr,
unsigned int fix);
/* Convenience wrappers for a single buffer of data */
extern u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize);
extern void ocfs2_hamming_fix_block(void *data, unsigned int blocksize,
unsigned int fix);
#endif
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