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It would be nice to know how often we get checksum failures. Even better, how many of them we can fix with the single bit ecc. So, we add a statistics structure. The structure can be installed into debugfs wherever the user wants. For ocfs2, we'll put it in the superblock-specific debugfs directory and pass it down from our higher-level functions. The stats are only registered with debugfs when the filesystem supports metadata ecc. Signed-off-by: Joel Becker <joel.becker@oracle.com>
108 lines
3.8 KiB
C
108 lines
3.8 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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/* Count errors and error correction from blockcheck.c */
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struct ocfs2_blockcheck_stats {
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spinlock_t b_lock;
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u64 b_check_count; /* Number of blocks we've checked */
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u64 b_failure_count; /* Number of failed checksums */
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u64 b_recover_count; /* Number of blocks fixed by ecc */
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/*
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* debugfs entries, used if this is passed to
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* ocfs2_blockcheck_stats_debugfs_install()
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*/
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struct dentry *b_debug_dir; /* Parent of the debugfs files */
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struct dentry *b_debug_check; /* Exposes b_check_count */
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struct dentry *b_debug_failure; /* Exposes b_failure_count */
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struct dentry *b_debug_recover; /* Exposes b_recover_count */
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};
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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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struct ocfs2_blockcheck_stats *stats);
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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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struct ocfs2_blockcheck_stats *stats);
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/* Debug Initialization */
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int ocfs2_blockcheck_stats_debugfs_install(struct ocfs2_blockcheck_stats *stats,
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struct dentry *parent);
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void ocfs2_blockcheck_stats_debugfs_remove(struct ocfs2_blockcheck_stats *stats);
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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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