1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* -*- mode: c; c-basic-offset: 8; -*-
3 * vim: noexpandtab sw=8 ts=8 sts=0:
4 *
5 * blockcheck.h
6 *
7 * Checksum and ECC codes for the OCFS2 userspace library.
8 *
9 * Copyright (C) 2004, 2008 Oracle. All rights reserved.
10 */
11
12 #ifndef OCFS2_BLOCKCHECK_H
13 #define OCFS2_BLOCKCHECK_H
14
15
16 /* Count errors and error correction from blockcheck.c */
17 struct ocfs2_blockcheck_stats {
18 spinlock_t b_lock;
19 u64 b_check_count; /* Number of blocks we've checked */
20 u64 b_failure_count; /* Number of failed checksums */
21 u64 b_recover_count; /* Number of blocks fixed by ecc */
22
23 /*
24 * debugfs entries, used if this is passed to
25 * ocfs2_blockcheck_stats_debugfs_install()
26 */
27 struct dentry *b_debug_dir; /* Parent of the debugfs files */
28 };
29
30
31 /* High level block API */
32 void ocfs2_compute_meta_ecc(struct super_block *sb, void *data,
33 struct ocfs2_block_check *bc);
34 int ocfs2_validate_meta_ecc(struct super_block *sb, void *data,
35 struct ocfs2_block_check *bc);
36 void ocfs2_compute_meta_ecc_bhs(struct super_block *sb,
37 struct buffer_head **bhs, int nr,
38 struct ocfs2_block_check *bc);
39 int ocfs2_validate_meta_ecc_bhs(struct super_block *sb,
40 struct buffer_head **bhs, int nr,
41 struct ocfs2_block_check *bc);
42
43 /* Lower level API */
44 void ocfs2_block_check_compute(void *data, size_t blocksize,
45 struct ocfs2_block_check *bc);
46 int ocfs2_block_check_validate(void *data, size_t blocksize,
47 struct ocfs2_block_check *bc,
48 struct ocfs2_blockcheck_stats *stats);
49 void ocfs2_block_check_compute_bhs(struct buffer_head **bhs, int nr,
50 struct ocfs2_block_check *bc);
51 int ocfs2_block_check_validate_bhs(struct buffer_head **bhs, int nr,
52 struct ocfs2_block_check *bc,
53 struct ocfs2_blockcheck_stats *stats);
54
55 /* Debug Initialization */
56 void ocfs2_blockcheck_stats_debugfs_install(struct ocfs2_blockcheck_stats *stats,
57 struct dentry *parent);
58 void ocfs2_blockcheck_stats_debugfs_remove(struct ocfs2_blockcheck_stats *stats);
59
60 /*
61 * Hamming code functions
62 */
63
64 /*
65 * Encoding hamming code parity bits for a buffer.
66 *
67 * This is the low level encoder function. It can be called across
68 * multiple hunks just like the crc32 code. 'd' is the number of bits
69 * _in_this_hunk_. nr is the bit offset of this hunk. So, if you had
70 * two 512B buffers, you would do it like so:
71 *
72 * parity = ocfs2_hamming_encode(0, buf1, 512 * 8, 0);
73 * parity = ocfs2_hamming_encode(parity, buf2, 512 * 8, 512 * 8);
74 *
75 * If you just have one buffer, use ocfs2_hamming_encode_block().
76 */
77 u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d,
78 unsigned int nr);
79 /*
80 * Fix a buffer with a bit error. The 'fix' is the original parity
81 * xor'd with the parity calculated now.
82 *
83 * Like ocfs2_hamming_encode(), this can handle hunks. nr is the bit
84 * offset of the current hunk. If bit to be fixed is not part of the
85 * current hunk, this does nothing.
86 *
87 * If you only have one buffer, use ocfs2_hamming_fix_block().
88 */
89 void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr,
90 unsigned int fix);
91
92 /* Convenience wrappers for a single buffer of data */
93 extern u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize);
94 extern void ocfs2_hamming_fix_block(void *data, unsigned int blocksize,
95 unsigned int fix);
96 #endif