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 };
  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