fs/ocfs2/blockcheck.h

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