fs/ocfs2/blockcheck.h

   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         struct dentry *b_debug_check;   /* Exposes b_check_count */
  29         struct dentry *b_debug_failure; /* Exposes b_failure_count */
  30         struct dentry *b_debug_recover; /* Exposes b_recover_count */
  31 };
  32
  33
  34 /* High level block API */
  35 void ocfs2_compute_meta_ecc(struct super_block *sb, void *data,
  36                             struct ocfs2_block_check *bc);
  37 int ocfs2_validate_meta_ecc(struct super_block *sb, void *data,
  38                             struct ocfs2_block_check *bc);
  39 void ocfs2_compute_meta_ecc_bhs(struct super_block *sb,
  40                                 struct buffer_head **bhs, int nr,
  41                                 struct ocfs2_block_check *bc);
  42 int ocfs2_validate_meta_ecc_bhs(struct super_block *sb,
  43                                 struct buffer_head **bhs, int nr,
  44                                 struct ocfs2_block_check *bc);
  45
  46 /* Lower level API */
  47 void ocfs2_block_check_compute(void *data, size_t blocksize,
  48                                struct ocfs2_block_check *bc);
  49 int ocfs2_block_check_validate(void *data, size_t blocksize,
  50                                struct ocfs2_block_check *bc,
  51                                struct ocfs2_blockcheck_stats *stats);
  52 void ocfs2_block_check_compute_bhs(struct buffer_head **bhs, int nr,
  53                                    struct ocfs2_block_check *bc);
  54 int ocfs2_block_check_validate_bhs(struct buffer_head **bhs, int nr,
  55                                    struct ocfs2_block_check *bc,
  56                                    struct ocfs2_blockcheck_stats *stats);
  57
  58 /* Debug Initialization */
  59 int ocfs2_blockcheck_stats_debugfs_install(struct ocfs2_blockcheck_stats *stats,
  60                                            struct dentry *parent);
  61 void ocfs2_blockcheck_stats_debugfs_remove(struct ocfs2_blockcheck_stats *stats);
  62
  63 /*
  64  * Hamming code functions
  65  */
  66
  67 /*
  68  * Encoding hamming code parity bits for a buffer.
  69  *
  70  * This is the low level encoder function.  It can be called across
  71  * multiple hunks just like the crc32 code.  'd' is the number of bits
  72  * _in_this_hunk_.  nr is the bit offset of this hunk.  So, if you had
  73  * two 512B buffers, you would do it like so:
  74  *
  75  * parity = ocfs2_hamming_encode(0, buf1, 512 * 8, 0);
  76  * parity = ocfs2_hamming_encode(parity, buf2, 512 * 8, 512 * 8);
  77  *
  78  * If you just have one buffer, use ocfs2_hamming_encode_block().
  79  */
  80 u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d,
  81                          unsigned int nr);
  82 /*
  83  * Fix a buffer with a bit error.  The 'fix' is the original parity
  84  * xor'd with the parity calculated now.
  85  *
  86  * Like ocfs2_hamming_encode(), this can handle hunks.  nr is the bit
  87  * offset of the current hunk.  If bit to be fixed is not part of the
  88  * current hunk, this does nothing.
  89  *
  90  * If you only have one buffer, use ocfs2_hamming_fix_block().
  91  */
  92 void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr,
  93                        unsigned int fix);
  94
  95 /* Convenience wrappers for a single buffer of data */
  96 extern u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize);
  97 extern void ocfs2_hamming_fix_block(void *data, unsigned int blocksize,
  98                                     unsigned int fix);
  99 #endif