Commit 70ad1ba7 authored by Joel Becker's avatar Joel Becker Committed by Mark Fasheh

ocfs2: Add the underlying blockcheck code.

This is the code that computes crc32 and ecc for ocfs2 metadata blocks.
There are high-level functions that check whether the filesystem has the
ecc feature, mid-level functions that work on a single block or array of
buffer_heads, and the low-level ecc hamming code that can handle
multiple buffers like crc32_le().

It's not hooked up to the filesystem yet.
Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent ab552d54
......@@ -12,6 +12,7 @@ obj-$(CONFIG_OCFS2_FS_USERSPACE_CLUSTER) += ocfs2_stack_user.o
ocfs2-objs := \
alloc.o \
aops.o \
blockcheck.o \
buffer_head_io.o \
dcache.o \
dir.o \
......
This diff is collapsed.
/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* blockcheck.h
*
* Checksum and ECC codes for the OCFS2 userspace library.
*
* Copyright (C) 2004, 2008 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License, version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#ifndef OCFS2_BLOCKCHECK_H
#define OCFS2_BLOCKCHECK_H
/* High level block API */
void ocfs2_compute_meta_ecc(struct super_block *sb, void *data,
struct ocfs2_block_check *bc);
int ocfs2_validate_meta_ecc(struct super_block *sb, void *data,
struct ocfs2_block_check *bc);
void ocfs2_compute_meta_ecc_bhs(struct super_block *sb,
struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc);
int ocfs2_validate_meta_ecc_bhs(struct super_block *sb,
struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc);
/* Lower level API */
void ocfs2_block_check_compute(void *data, size_t blocksize,
struct ocfs2_block_check *bc);
int ocfs2_block_check_validate(void *data, size_t blocksize,
struct ocfs2_block_check *bc);
void ocfs2_block_check_compute_bhs(struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc);
int ocfs2_block_check_validate_bhs(struct buffer_head **bhs, int nr,
struct ocfs2_block_check *bc);
/*
* Hamming code functions
*/
/*
* Encoding hamming code parity bits for a buffer.
*
* This is the low level encoder function. It can be called across
* multiple hunks just like the crc32 code. 'd' is the number of bits
* _in_this_hunk_. nr is the bit offset of this hunk. So, if you had
* two 512B buffers, you would do it like so:
*
* parity = ocfs2_hamming_encode(0, buf1, 512 * 8, 0);
* parity = ocfs2_hamming_encode(parity, buf2, 512 * 8, 512 * 8);
*
* If you just have one buffer, use ocfs2_hamming_encode_block().
*/
u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d,
unsigned int nr);
/*
* Fix a buffer with a bit error. The 'fix' is the original parity
* xor'd with the parity calculated now.
*
* Like ocfs2_hamming_encode(), this can handle hunks. nr is the bit
* offset of the current hunk. If bit to be fixed is not part of the
* current hunk, this does nothing.
*
* If you only have one buffer, use ocfs2_hamming_fix_block().
*/
void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr,
unsigned int fix);
/* Convenience wrappers for a single buffer of data */
extern u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize);
extern void ocfs2_hamming_fix_block(void *data, unsigned int blocksize,
unsigned int fix);
#endif
......@@ -382,6 +382,13 @@ static inline int ocfs2_supports_xattr(struct ocfs2_super *osb)
return 0;
}
static inline int ocfs2_meta_ecc(struct ocfs2_super *osb)
{
if (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_META_ECC)
return 1;
return 0;
}
/* set / clear functions because cluster events can make these happen
* in parallel so we want the transitions to be atomic. this also
* means that any future flags osb_flags must be protected by spinlock
......@@ -615,5 +622,6 @@ static inline s16 ocfs2_get_inode_steal_slot(struct ocfs2_super *osb)
#define ocfs2_clear_bit ext2_clear_bit
#define ocfs2_test_bit ext2_test_bit
#define ocfs2_find_next_zero_bit ext2_find_next_zero_bit
#define ocfs2_find_next_bit ext2_find_next_bit
#endif /* OCFS2_H */
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