170ad1ba7SJoel Becker /* -*- mode: c; c-basic-offset: 8; -*- 270ad1ba7SJoel Becker * vim: noexpandtab sw=8 ts=8 sts=0: 370ad1ba7SJoel Becker * 470ad1ba7SJoel Becker * blockcheck.c 570ad1ba7SJoel Becker * 670ad1ba7SJoel Becker * Checksum and ECC codes for the OCFS2 userspace library. 770ad1ba7SJoel Becker * 870ad1ba7SJoel Becker * Copyright (C) 2006, 2008 Oracle. All rights reserved. 970ad1ba7SJoel Becker * 1070ad1ba7SJoel Becker * This program is free software; you can redistribute it and/or 1170ad1ba7SJoel Becker * modify it under the terms of the GNU General Public 1270ad1ba7SJoel Becker * License, version 2, as published by the Free Software Foundation. 1370ad1ba7SJoel Becker * 1470ad1ba7SJoel Becker * This program is distributed in the hope that it will be useful, 1570ad1ba7SJoel Becker * but WITHOUT ANY WARRANTY; without even the implied warranty of 1670ad1ba7SJoel Becker * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 1770ad1ba7SJoel Becker * General Public License for more details. 1870ad1ba7SJoel Becker */ 1970ad1ba7SJoel Becker 2070ad1ba7SJoel Becker #include <linux/kernel.h> 2170ad1ba7SJoel Becker #include <linux/types.h> 2270ad1ba7SJoel Becker #include <linux/crc32.h> 2370ad1ba7SJoel Becker #include <linux/buffer_head.h> 2470ad1ba7SJoel Becker #include <linux/bitops.h> 2573be192bSJoel Becker #include <linux/debugfs.h> 2673be192bSJoel Becker #include <linux/module.h> 2773be192bSJoel Becker #include <linux/fs.h> 2870ad1ba7SJoel Becker #include <asm/byteorder.h> 2970ad1ba7SJoel Becker 30d6b32bbbSJoel Becker #include <cluster/masklog.h> 31d6b32bbbSJoel Becker 3270ad1ba7SJoel Becker #include "ocfs2.h" 3370ad1ba7SJoel Becker 3470ad1ba7SJoel Becker #include "blockcheck.h" 3570ad1ba7SJoel Becker 3670ad1ba7SJoel Becker 3770ad1ba7SJoel Becker /* 3870ad1ba7SJoel Becker * We use the following conventions: 3970ad1ba7SJoel Becker * 4070ad1ba7SJoel Becker * d = # data bits 4170ad1ba7SJoel Becker * p = # parity bits 4270ad1ba7SJoel Becker * c = # total code bits (d + p) 4370ad1ba7SJoel Becker */ 4470ad1ba7SJoel Becker 457bb458a5SJoel Becker 467bb458a5SJoel Becker /* 4770ad1ba7SJoel Becker * Calculate the bit offset in the hamming code buffer based on the bit's 4870ad1ba7SJoel Becker * offset in the data buffer. Since the hamming code reserves all 4970ad1ba7SJoel Becker * power-of-two bits for parity, the data bit number and the code bit 50bf48aabbSUwe Kleine-König * number are offset by all the parity bits beforehand. 5170ad1ba7SJoel Becker * 5270ad1ba7SJoel Becker * Recall that bit numbers in hamming code are 1-based. This function 5370ad1ba7SJoel Becker * takes the 0-based data bit from the caller. 5470ad1ba7SJoel Becker * 5570ad1ba7SJoel Becker * An example. Take bit 1 of the data buffer. 1 is a power of two (2^0), 5670ad1ba7SJoel Becker * so it's a parity bit. 2 is a power of two (2^1), so it's a parity bit. 5770ad1ba7SJoel Becker * 3 is not a power of two. So bit 1 of the data buffer ends up as bit 3 5870ad1ba7SJoel Becker * in the code buffer. 5958896c4dSJoel Becker * 6058896c4dSJoel Becker * The caller can pass in *p if it wants to keep track of the most recent 6158896c4dSJoel Becker * number of parity bits added. This allows the function to start the 6258896c4dSJoel Becker * calculation at the last place. 6370ad1ba7SJoel Becker */ 6458896c4dSJoel Becker static unsigned int calc_code_bit(unsigned int i, unsigned int *p_cache) 6570ad1ba7SJoel Becker { 6658896c4dSJoel Becker unsigned int b, p = 0; 6770ad1ba7SJoel Becker 6870ad1ba7SJoel Becker /* 6970ad1ba7SJoel Becker * Data bits are 0-based, but we're talking code bits, which 7070ad1ba7SJoel Becker * are 1-based. 7170ad1ba7SJoel Becker */ 7270ad1ba7SJoel Becker b = i + 1; 7370ad1ba7SJoel Becker 7458896c4dSJoel Becker /* Use the cache if it is there */ 7558896c4dSJoel Becker if (p_cache) 7658896c4dSJoel Becker p = *p_cache; 777bb458a5SJoel Becker b += p; 787bb458a5SJoel Becker 797bb458a5SJoel Becker /* 8070ad1ba7SJoel Becker * For every power of two below our bit number, bump our bit. 8170ad1ba7SJoel Becker * 8258896c4dSJoel Becker * We compare with (b + 1) because we have to compare with what b 8370ad1ba7SJoel Becker * would be _if_ it were bumped up by the parity bit. Capice? 847bb458a5SJoel Becker * 8558896c4dSJoel Becker * p is set above. 8670ad1ba7SJoel Becker */ 8758896c4dSJoel Becker for (; (1 << p) < (b + 1); p++) 8870ad1ba7SJoel Becker b++; 8970ad1ba7SJoel Becker 9058896c4dSJoel Becker if (p_cache) 9158896c4dSJoel Becker *p_cache = p; 9258896c4dSJoel Becker 9370ad1ba7SJoel Becker return b; 9470ad1ba7SJoel Becker } 9570ad1ba7SJoel Becker 9670ad1ba7SJoel Becker /* 9770ad1ba7SJoel Becker * This is the low level encoder function. It can be called across 9870ad1ba7SJoel Becker * multiple hunks just like the crc32 code. 'd' is the number of bits 9970ad1ba7SJoel Becker * _in_this_hunk_. nr is the bit offset of this hunk. So, if you had 10070ad1ba7SJoel Becker * two 512B buffers, you would do it like so: 10170ad1ba7SJoel Becker * 10270ad1ba7SJoel Becker * parity = ocfs2_hamming_encode(0, buf1, 512 * 8, 0); 10370ad1ba7SJoel Becker * parity = ocfs2_hamming_encode(parity, buf2, 512 * 8, 512 * 8); 10470ad1ba7SJoel Becker * 10570ad1ba7SJoel Becker * If you just have one buffer, use ocfs2_hamming_encode_block(). 10670ad1ba7SJoel Becker */ 10770ad1ba7SJoel Becker u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d, unsigned int nr) 10870ad1ba7SJoel Becker { 10958896c4dSJoel Becker unsigned int i, b, p = 0; 11070ad1ba7SJoel Becker 111e798b3f8SJoel Becker BUG_ON(!d); 11270ad1ba7SJoel Becker 11370ad1ba7SJoel Becker /* 11470ad1ba7SJoel Becker * b is the hamming code bit number. Hamming code specifies a 11570ad1ba7SJoel Becker * 1-based array, but C uses 0-based. So 'i' is for C, and 'b' is 11670ad1ba7SJoel Becker * for the algorithm. 11770ad1ba7SJoel Becker * 11870ad1ba7SJoel Becker * The i++ in the for loop is so that the start offset passed 11970ad1ba7SJoel Becker * to ocfs2_find_next_bit_set() is one greater than the previously 12070ad1ba7SJoel Becker * found bit. 12170ad1ba7SJoel Becker */ 12270ad1ba7SJoel Becker for (i = 0; (i = ocfs2_find_next_bit(data, d, i)) < d; i++) 12370ad1ba7SJoel Becker { 12470ad1ba7SJoel Becker /* 12570ad1ba7SJoel Becker * i is the offset in this hunk, nr + i is the total bit 12670ad1ba7SJoel Becker * offset. 12770ad1ba7SJoel Becker */ 12858896c4dSJoel Becker b = calc_code_bit(nr + i, &p); 12970ad1ba7SJoel Becker 13070ad1ba7SJoel Becker /* 13170ad1ba7SJoel Becker * Data bits in the resultant code are checked by 13270ad1ba7SJoel Becker * parity bits that are part of the bit number 13370ad1ba7SJoel Becker * representation. Huh? 13470ad1ba7SJoel Becker * 13570ad1ba7SJoel Becker * <wikipedia href="http://en.wikipedia.org/wiki/Hamming_code"> 13670ad1ba7SJoel Becker * In other words, the parity bit at position 2^k 13770ad1ba7SJoel Becker * checks bits in positions having bit k set in 13870ad1ba7SJoel Becker * their binary representation. Conversely, for 13970ad1ba7SJoel Becker * instance, bit 13, i.e. 1101(2), is checked by 14070ad1ba7SJoel Becker * bits 1000(2) = 8, 0100(2)=4 and 0001(2) = 1. 14170ad1ba7SJoel Becker * </wikipedia> 14270ad1ba7SJoel Becker * 14370ad1ba7SJoel Becker * Note that 'k' is the _code_ bit number. 'b' in 14470ad1ba7SJoel Becker * our loop. 14570ad1ba7SJoel Becker */ 146e798b3f8SJoel Becker parity ^= b; 14770ad1ba7SJoel Becker } 14870ad1ba7SJoel Becker 14970ad1ba7SJoel Becker /* While the data buffer was treated as little endian, the 15070ad1ba7SJoel Becker * return value is in host endian. */ 15170ad1ba7SJoel Becker return parity; 15270ad1ba7SJoel Becker } 15370ad1ba7SJoel Becker 15470ad1ba7SJoel Becker u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize) 15570ad1ba7SJoel Becker { 15670ad1ba7SJoel Becker return ocfs2_hamming_encode(0, data, blocksize * 8, 0); 15770ad1ba7SJoel Becker } 15870ad1ba7SJoel Becker 15970ad1ba7SJoel Becker /* 16070ad1ba7SJoel Becker * Like ocfs2_hamming_encode(), this can handle hunks. nr is the bit 16170ad1ba7SJoel Becker * offset of the current hunk. If bit to be fixed is not part of the 16270ad1ba7SJoel Becker * current hunk, this does nothing. 16370ad1ba7SJoel Becker * 16470ad1ba7SJoel Becker * If you only have one hunk, use ocfs2_hamming_fix_block(). 16570ad1ba7SJoel Becker */ 16670ad1ba7SJoel Becker void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr, 16770ad1ba7SJoel Becker unsigned int fix) 16870ad1ba7SJoel Becker { 16970ad1ba7SJoel Becker unsigned int i, b; 17070ad1ba7SJoel Becker 171e798b3f8SJoel Becker BUG_ON(!d); 17270ad1ba7SJoel Becker 17370ad1ba7SJoel Becker /* 17470ad1ba7SJoel Becker * If the bit to fix has an hweight of 1, it's a parity bit. One 17570ad1ba7SJoel Becker * busted parity bit is its own error. Nothing to do here. 17670ad1ba7SJoel Becker */ 17770ad1ba7SJoel Becker if (hweight32(fix) == 1) 17870ad1ba7SJoel Becker return; 17970ad1ba7SJoel Becker 18070ad1ba7SJoel Becker /* 18170ad1ba7SJoel Becker * nr + d is the bit right past the data hunk we're looking at. 18270ad1ba7SJoel Becker * If fix after that, nothing to do 18370ad1ba7SJoel Becker */ 18458896c4dSJoel Becker if (fix >= calc_code_bit(nr + d, NULL)) 18570ad1ba7SJoel Becker return; 18670ad1ba7SJoel Becker 18770ad1ba7SJoel Becker /* 18870ad1ba7SJoel Becker * nr is the offset in the data hunk we're starting at. Let's 18970ad1ba7SJoel Becker * start b at the offset in the code buffer. See hamming_encode() 19070ad1ba7SJoel Becker * for a more detailed description of 'b'. 19170ad1ba7SJoel Becker */ 19258896c4dSJoel Becker b = calc_code_bit(nr, NULL); 19370ad1ba7SJoel Becker /* If the fix is before this hunk, nothing to do */ 19470ad1ba7SJoel Becker if (fix < b) 19570ad1ba7SJoel Becker return; 19670ad1ba7SJoel Becker 19770ad1ba7SJoel Becker for (i = 0; i < d; i++, b++) 19870ad1ba7SJoel Becker { 19970ad1ba7SJoel Becker /* Skip past parity bits */ 20070ad1ba7SJoel Becker while (hweight32(b) == 1) 20170ad1ba7SJoel Becker b++; 20270ad1ba7SJoel Becker 20370ad1ba7SJoel Becker /* 20470ad1ba7SJoel Becker * i is the offset in this data hunk. 20570ad1ba7SJoel Becker * nr + i is the offset in the total data buffer. 20670ad1ba7SJoel Becker * b is the offset in the total code buffer. 20770ad1ba7SJoel Becker * 20870ad1ba7SJoel Becker * Thus, when b == fix, bit i in the current hunk needs 20970ad1ba7SJoel Becker * fixing. 21070ad1ba7SJoel Becker */ 21170ad1ba7SJoel Becker if (b == fix) 21270ad1ba7SJoel Becker { 21370ad1ba7SJoel Becker if (ocfs2_test_bit(i, data)) 21470ad1ba7SJoel Becker ocfs2_clear_bit(i, data); 21570ad1ba7SJoel Becker else 21670ad1ba7SJoel Becker ocfs2_set_bit(i, data); 21770ad1ba7SJoel Becker break; 21870ad1ba7SJoel Becker } 21970ad1ba7SJoel Becker } 22070ad1ba7SJoel Becker } 22170ad1ba7SJoel Becker 22270ad1ba7SJoel Becker void ocfs2_hamming_fix_block(void *data, unsigned int blocksize, 22370ad1ba7SJoel Becker unsigned int fix) 22470ad1ba7SJoel Becker { 22570ad1ba7SJoel Becker ocfs2_hamming_fix(data, blocksize * 8, 0, fix); 22670ad1ba7SJoel Becker } 22770ad1ba7SJoel Becker 22873be192bSJoel Becker 22973be192bSJoel Becker /* 23073be192bSJoel Becker * Debugfs handling. 23173be192bSJoel Becker */ 23273be192bSJoel Becker 23373be192bSJoel Becker #ifdef CONFIG_DEBUG_FS 23473be192bSJoel Becker 23573be192bSJoel Becker static int blockcheck_u64_get(void *data, u64 *val) 23673be192bSJoel Becker { 23773be192bSJoel Becker *val = *(u64 *)data; 23873be192bSJoel Becker return 0; 23973be192bSJoel Becker } 24073be192bSJoel Becker DEFINE_SIMPLE_ATTRIBUTE(blockcheck_fops, blockcheck_u64_get, NULL, "%llu\n"); 24173be192bSJoel Becker 24273be192bSJoel Becker static struct dentry *blockcheck_debugfs_create(const char *name, 24373be192bSJoel Becker struct dentry *parent, 24473be192bSJoel Becker u64 *value) 24573be192bSJoel Becker { 24673be192bSJoel Becker return debugfs_create_file(name, S_IFREG | S_IRUSR, parent, value, 24773be192bSJoel Becker &blockcheck_fops); 24873be192bSJoel Becker } 24973be192bSJoel Becker 25073be192bSJoel Becker static void ocfs2_blockcheck_debug_remove(struct ocfs2_blockcheck_stats *stats) 25173be192bSJoel Becker { 25273be192bSJoel Becker if (stats) { 25373be192bSJoel Becker debugfs_remove(stats->b_debug_check); 25473be192bSJoel Becker stats->b_debug_check = NULL; 25573be192bSJoel Becker debugfs_remove(stats->b_debug_failure); 25673be192bSJoel Becker stats->b_debug_failure = NULL; 25773be192bSJoel Becker debugfs_remove(stats->b_debug_recover); 25873be192bSJoel Becker stats->b_debug_recover = NULL; 25973be192bSJoel Becker debugfs_remove(stats->b_debug_dir); 26073be192bSJoel Becker stats->b_debug_dir = NULL; 26173be192bSJoel Becker } 26273be192bSJoel Becker } 26373be192bSJoel Becker 26473be192bSJoel Becker static int ocfs2_blockcheck_debug_install(struct ocfs2_blockcheck_stats *stats, 26573be192bSJoel Becker struct dentry *parent) 26673be192bSJoel Becker { 26773be192bSJoel Becker int rc = -EINVAL; 26873be192bSJoel Becker 26973be192bSJoel Becker if (!stats) 27073be192bSJoel Becker goto out; 27173be192bSJoel Becker 27273be192bSJoel Becker stats->b_debug_dir = debugfs_create_dir("blockcheck", parent); 27373be192bSJoel Becker if (!stats->b_debug_dir) 27473be192bSJoel Becker goto out; 27573be192bSJoel Becker 27673be192bSJoel Becker stats->b_debug_check = 27773be192bSJoel Becker blockcheck_debugfs_create("blocks_checked", 27873be192bSJoel Becker stats->b_debug_dir, 27973be192bSJoel Becker &stats->b_check_count); 28073be192bSJoel Becker 28173be192bSJoel Becker stats->b_debug_failure = 28273be192bSJoel Becker blockcheck_debugfs_create("checksums_failed", 28373be192bSJoel Becker stats->b_debug_dir, 28473be192bSJoel Becker &stats->b_failure_count); 28573be192bSJoel Becker 28673be192bSJoel Becker stats->b_debug_recover = 28773be192bSJoel Becker blockcheck_debugfs_create("ecc_recoveries", 28873be192bSJoel Becker stats->b_debug_dir, 28973be192bSJoel Becker &stats->b_recover_count); 29073be192bSJoel Becker if (stats->b_debug_check && stats->b_debug_failure && 29173be192bSJoel Becker stats->b_debug_recover) 29273be192bSJoel Becker rc = 0; 29373be192bSJoel Becker 29473be192bSJoel Becker out: 29573be192bSJoel Becker if (rc) 29673be192bSJoel Becker ocfs2_blockcheck_debug_remove(stats); 29773be192bSJoel Becker return rc; 29873be192bSJoel Becker } 29973be192bSJoel Becker #else 30073be192bSJoel Becker static inline int ocfs2_blockcheck_debug_install(struct ocfs2_blockcheck_stats *stats, 30173be192bSJoel Becker struct dentry *parent) 30273be192bSJoel Becker { 30373be192bSJoel Becker return 0; 30473be192bSJoel Becker } 30573be192bSJoel Becker 30673be192bSJoel Becker static inline void ocfs2_blockcheck_debug_remove(struct ocfs2_blockcheck_stats *stats) 30773be192bSJoel Becker { 30873be192bSJoel Becker } 30973be192bSJoel Becker #endif /* CONFIG_DEBUG_FS */ 31073be192bSJoel Becker 31173be192bSJoel Becker /* Always-called wrappers for starting and stopping the debugfs files */ 31273be192bSJoel Becker int ocfs2_blockcheck_stats_debugfs_install(struct ocfs2_blockcheck_stats *stats, 31373be192bSJoel Becker struct dentry *parent) 31473be192bSJoel Becker { 31573be192bSJoel Becker return ocfs2_blockcheck_debug_install(stats, parent); 31673be192bSJoel Becker } 31773be192bSJoel Becker 31873be192bSJoel Becker void ocfs2_blockcheck_stats_debugfs_remove(struct ocfs2_blockcheck_stats *stats) 31973be192bSJoel Becker { 32073be192bSJoel Becker ocfs2_blockcheck_debug_remove(stats); 32173be192bSJoel Becker } 32273be192bSJoel Becker 32373be192bSJoel Becker static void ocfs2_blockcheck_inc_check(struct ocfs2_blockcheck_stats *stats) 32473be192bSJoel Becker { 32573be192bSJoel Becker u64 new_count; 32673be192bSJoel Becker 32773be192bSJoel Becker if (!stats) 32873be192bSJoel Becker return; 32973be192bSJoel Becker 33073be192bSJoel Becker spin_lock(&stats->b_lock); 33173be192bSJoel Becker stats->b_check_count++; 33273be192bSJoel Becker new_count = stats->b_check_count; 33373be192bSJoel Becker spin_unlock(&stats->b_lock); 33473be192bSJoel Becker 33573be192bSJoel Becker if (!new_count) 33673be192bSJoel Becker mlog(ML_NOTICE, "Block check count has wrapped\n"); 33773be192bSJoel Becker } 33873be192bSJoel Becker 33973be192bSJoel Becker static void ocfs2_blockcheck_inc_failure(struct ocfs2_blockcheck_stats *stats) 34073be192bSJoel Becker { 34173be192bSJoel Becker u64 new_count; 34273be192bSJoel Becker 34373be192bSJoel Becker if (!stats) 34473be192bSJoel Becker return; 34573be192bSJoel Becker 34673be192bSJoel Becker spin_lock(&stats->b_lock); 34773be192bSJoel Becker stats->b_failure_count++; 34873be192bSJoel Becker new_count = stats->b_failure_count; 34973be192bSJoel Becker spin_unlock(&stats->b_lock); 35073be192bSJoel Becker 35173be192bSJoel Becker if (!new_count) 35273be192bSJoel Becker mlog(ML_NOTICE, "Checksum failure count has wrapped\n"); 35373be192bSJoel Becker } 35473be192bSJoel Becker 35573be192bSJoel Becker static void ocfs2_blockcheck_inc_recover(struct ocfs2_blockcheck_stats *stats) 35673be192bSJoel Becker { 35773be192bSJoel Becker u64 new_count; 35873be192bSJoel Becker 35973be192bSJoel Becker if (!stats) 36073be192bSJoel Becker return; 36173be192bSJoel Becker 36273be192bSJoel Becker spin_lock(&stats->b_lock); 36373be192bSJoel Becker stats->b_recover_count++; 36473be192bSJoel Becker new_count = stats->b_recover_count; 36573be192bSJoel Becker spin_unlock(&stats->b_lock); 36673be192bSJoel Becker 36773be192bSJoel Becker if (!new_count) 36873be192bSJoel Becker mlog(ML_NOTICE, "ECC recovery count has wrapped\n"); 36973be192bSJoel Becker } 37073be192bSJoel Becker 37173be192bSJoel Becker 37273be192bSJoel Becker 37373be192bSJoel Becker /* 37473be192bSJoel Becker * These are the low-level APIs for using the ocfs2_block_check structure. 37573be192bSJoel Becker */ 37673be192bSJoel Becker 37770ad1ba7SJoel Becker /* 37870ad1ba7SJoel Becker * This function generates check information for a block. 37970ad1ba7SJoel Becker * data is the block to be checked. bc is a pointer to the 38070ad1ba7SJoel Becker * ocfs2_block_check structure describing the crc32 and the ecc. 38170ad1ba7SJoel Becker * 38270ad1ba7SJoel Becker * bc should be a pointer inside data, as the function will 38370ad1ba7SJoel Becker * take care of zeroing it before calculating the check information. If 38470ad1ba7SJoel Becker * bc does not point inside data, the caller must make sure any inline 38570ad1ba7SJoel Becker * ocfs2_block_check structures are zeroed. 38670ad1ba7SJoel Becker * 38770ad1ba7SJoel Becker * The data buffer must be in on-disk endian (little endian for ocfs2). 38870ad1ba7SJoel Becker * bc will be filled with little-endian values and will be ready to go to 38970ad1ba7SJoel Becker * disk. 39070ad1ba7SJoel Becker */ 39170ad1ba7SJoel Becker void ocfs2_block_check_compute(void *data, size_t blocksize, 39270ad1ba7SJoel Becker struct ocfs2_block_check *bc) 39370ad1ba7SJoel Becker { 39470ad1ba7SJoel Becker u32 crc; 39570ad1ba7SJoel Becker u32 ecc; 39670ad1ba7SJoel Becker 39770ad1ba7SJoel Becker memset(bc, 0, sizeof(struct ocfs2_block_check)); 39870ad1ba7SJoel Becker 39970ad1ba7SJoel Becker crc = crc32_le(~0, data, blocksize); 40070ad1ba7SJoel Becker ecc = ocfs2_hamming_encode_block(data, blocksize); 40170ad1ba7SJoel Becker 40270ad1ba7SJoel Becker /* 40370ad1ba7SJoel Becker * No ecc'd ocfs2 structure is larger than 4K, so ecc will be no 40470ad1ba7SJoel Becker * larger than 16 bits. 40570ad1ba7SJoel Becker */ 4064be929beSAlexey Dobriyan BUG_ON(ecc > USHRT_MAX); 40770ad1ba7SJoel Becker 40870ad1ba7SJoel Becker bc->bc_crc32e = cpu_to_le32(crc); 40970ad1ba7SJoel Becker bc->bc_ecc = cpu_to_le16((u16)ecc); 41070ad1ba7SJoel Becker } 41170ad1ba7SJoel Becker 41270ad1ba7SJoel Becker /* 41370ad1ba7SJoel Becker * This function validates existing check information. Like _compute, 41470ad1ba7SJoel Becker * the function will take care of zeroing bc before calculating check codes. 41570ad1ba7SJoel Becker * If bc is not a pointer inside data, the caller must have zeroed any 41670ad1ba7SJoel Becker * inline ocfs2_block_check structures. 41770ad1ba7SJoel Becker * 41870ad1ba7SJoel Becker * Again, the data passed in should be the on-disk endian. 41970ad1ba7SJoel Becker */ 42070ad1ba7SJoel Becker int ocfs2_block_check_validate(void *data, size_t blocksize, 42173be192bSJoel Becker struct ocfs2_block_check *bc, 42273be192bSJoel Becker struct ocfs2_blockcheck_stats *stats) 42370ad1ba7SJoel Becker { 42470ad1ba7SJoel Becker int rc = 0; 42570ad1ba7SJoel Becker struct ocfs2_block_check check; 42670ad1ba7SJoel Becker u32 crc, ecc; 42770ad1ba7SJoel Becker 42873be192bSJoel Becker ocfs2_blockcheck_inc_check(stats); 42973be192bSJoel Becker 43070ad1ba7SJoel Becker check.bc_crc32e = le32_to_cpu(bc->bc_crc32e); 43170ad1ba7SJoel Becker check.bc_ecc = le16_to_cpu(bc->bc_ecc); 43270ad1ba7SJoel Becker 43370ad1ba7SJoel Becker memset(bc, 0, sizeof(struct ocfs2_block_check)); 43470ad1ba7SJoel Becker 43570ad1ba7SJoel Becker /* Fast path - if the crc32 validates, we're good to go */ 43670ad1ba7SJoel Becker crc = crc32_le(~0, data, blocksize); 43770ad1ba7SJoel Becker if (crc == check.bc_crc32e) 43870ad1ba7SJoel Becker goto out; 43970ad1ba7SJoel Becker 44073be192bSJoel Becker ocfs2_blockcheck_inc_failure(stats); 441d6b32bbbSJoel Becker mlog(ML_ERROR, 442dc696aceSSunil Mushran "CRC32 failed: stored: 0x%x, computed 0x%x. Applying ECC.\n", 443d6b32bbbSJoel Becker (unsigned int)check.bc_crc32e, (unsigned int)crc); 444d6b32bbbSJoel Becker 44570ad1ba7SJoel Becker /* Ok, try ECC fixups */ 44670ad1ba7SJoel Becker ecc = ocfs2_hamming_encode_block(data, blocksize); 44770ad1ba7SJoel Becker ocfs2_hamming_fix_block(data, blocksize, ecc ^ check.bc_ecc); 44870ad1ba7SJoel Becker 44970ad1ba7SJoel Becker /* And check the crc32 again */ 45070ad1ba7SJoel Becker crc = crc32_le(~0, data, blocksize); 45173be192bSJoel Becker if (crc == check.bc_crc32e) { 45273be192bSJoel Becker ocfs2_blockcheck_inc_recover(stats); 45370ad1ba7SJoel Becker goto out; 45473be192bSJoel Becker } 45570ad1ba7SJoel Becker 456dc696aceSSunil Mushran mlog(ML_ERROR, "Fixed CRC32 failed: stored: 0x%x, computed 0x%x\n", 457d6b32bbbSJoel Becker (unsigned int)check.bc_crc32e, (unsigned int)crc); 458d6b32bbbSJoel Becker 45970ad1ba7SJoel Becker rc = -EIO; 46070ad1ba7SJoel Becker 46170ad1ba7SJoel Becker out: 46270ad1ba7SJoel Becker bc->bc_crc32e = cpu_to_le32(check.bc_crc32e); 46370ad1ba7SJoel Becker bc->bc_ecc = cpu_to_le16(check.bc_ecc); 46470ad1ba7SJoel Becker 46570ad1ba7SJoel Becker return rc; 46670ad1ba7SJoel Becker } 46770ad1ba7SJoel Becker 46870ad1ba7SJoel Becker /* 46970ad1ba7SJoel Becker * This function generates check information for a list of buffer_heads. 47070ad1ba7SJoel Becker * bhs is the blocks to be checked. bc is a pointer to the 47170ad1ba7SJoel Becker * ocfs2_block_check structure describing the crc32 and the ecc. 47270ad1ba7SJoel Becker * 47370ad1ba7SJoel Becker * bc should be a pointer inside data, as the function will 47470ad1ba7SJoel Becker * take care of zeroing it before calculating the check information. If 47570ad1ba7SJoel Becker * bc does not point inside data, the caller must make sure any inline 47670ad1ba7SJoel Becker * ocfs2_block_check structures are zeroed. 47770ad1ba7SJoel Becker * 47870ad1ba7SJoel Becker * The data buffer must be in on-disk endian (little endian for ocfs2). 47970ad1ba7SJoel Becker * bc will be filled with little-endian values and will be ready to go to 48070ad1ba7SJoel Becker * disk. 48170ad1ba7SJoel Becker */ 48270ad1ba7SJoel Becker void ocfs2_block_check_compute_bhs(struct buffer_head **bhs, int nr, 48370ad1ba7SJoel Becker struct ocfs2_block_check *bc) 48470ad1ba7SJoel Becker { 48570ad1ba7SJoel Becker int i; 48670ad1ba7SJoel Becker u32 crc, ecc; 48770ad1ba7SJoel Becker 48870ad1ba7SJoel Becker BUG_ON(nr < 0); 48970ad1ba7SJoel Becker 49070ad1ba7SJoel Becker if (!nr) 49170ad1ba7SJoel Becker return; 49270ad1ba7SJoel Becker 49370ad1ba7SJoel Becker memset(bc, 0, sizeof(struct ocfs2_block_check)); 49470ad1ba7SJoel Becker 49570ad1ba7SJoel Becker for (i = 0, crc = ~0, ecc = 0; i < nr; i++) { 49670ad1ba7SJoel Becker crc = crc32_le(crc, bhs[i]->b_data, bhs[i]->b_size); 49770ad1ba7SJoel Becker /* 49870ad1ba7SJoel Becker * The number of bits in a buffer is obviously b_size*8. 49970ad1ba7SJoel Becker * The offset of this buffer is b_size*i, so the bit offset 50070ad1ba7SJoel Becker * of this buffer is b_size*8*i. 50170ad1ba7SJoel Becker */ 50270ad1ba7SJoel Becker ecc = (u16)ocfs2_hamming_encode(ecc, bhs[i]->b_data, 50370ad1ba7SJoel Becker bhs[i]->b_size * 8, 50470ad1ba7SJoel Becker bhs[i]->b_size * 8 * i); 50570ad1ba7SJoel Becker } 50670ad1ba7SJoel Becker 50770ad1ba7SJoel Becker /* 50870ad1ba7SJoel Becker * No ecc'd ocfs2 structure is larger than 4K, so ecc will be no 50970ad1ba7SJoel Becker * larger than 16 bits. 51070ad1ba7SJoel Becker */ 5114be929beSAlexey Dobriyan BUG_ON(ecc > USHRT_MAX); 51270ad1ba7SJoel Becker 51370ad1ba7SJoel Becker bc->bc_crc32e = cpu_to_le32(crc); 51470ad1ba7SJoel Becker bc->bc_ecc = cpu_to_le16((u16)ecc); 51570ad1ba7SJoel Becker } 51670ad1ba7SJoel Becker 51770ad1ba7SJoel Becker /* 51870ad1ba7SJoel Becker * This function validates existing check information on a list of 51970ad1ba7SJoel Becker * buffer_heads. Like _compute_bhs, the function will take care of 52070ad1ba7SJoel Becker * zeroing bc before calculating check codes. If bc is not a pointer 52170ad1ba7SJoel Becker * inside data, the caller must have zeroed any inline 52270ad1ba7SJoel Becker * ocfs2_block_check structures. 52370ad1ba7SJoel Becker * 52470ad1ba7SJoel Becker * Again, the data passed in should be the on-disk endian. 52570ad1ba7SJoel Becker */ 52670ad1ba7SJoel Becker int ocfs2_block_check_validate_bhs(struct buffer_head **bhs, int nr, 52773be192bSJoel Becker struct ocfs2_block_check *bc, 52873be192bSJoel Becker struct ocfs2_blockcheck_stats *stats) 52970ad1ba7SJoel Becker { 53070ad1ba7SJoel Becker int i, rc = 0; 53170ad1ba7SJoel Becker struct ocfs2_block_check check; 53270ad1ba7SJoel Becker u32 crc, ecc, fix; 53370ad1ba7SJoel Becker 53470ad1ba7SJoel Becker BUG_ON(nr < 0); 53570ad1ba7SJoel Becker 53670ad1ba7SJoel Becker if (!nr) 53770ad1ba7SJoel Becker return 0; 53870ad1ba7SJoel Becker 53973be192bSJoel Becker ocfs2_blockcheck_inc_check(stats); 54073be192bSJoel Becker 54170ad1ba7SJoel Becker check.bc_crc32e = le32_to_cpu(bc->bc_crc32e); 54270ad1ba7SJoel Becker check.bc_ecc = le16_to_cpu(bc->bc_ecc); 54370ad1ba7SJoel Becker 54470ad1ba7SJoel Becker memset(bc, 0, sizeof(struct ocfs2_block_check)); 54570ad1ba7SJoel Becker 54670ad1ba7SJoel Becker /* Fast path - if the crc32 validates, we're good to go */ 54770ad1ba7SJoel Becker for (i = 0, crc = ~0; i < nr; i++) 54870ad1ba7SJoel Becker crc = crc32_le(crc, bhs[i]->b_data, bhs[i]->b_size); 54970ad1ba7SJoel Becker if (crc == check.bc_crc32e) 55070ad1ba7SJoel Becker goto out; 55170ad1ba7SJoel Becker 55273be192bSJoel Becker ocfs2_blockcheck_inc_failure(stats); 55370ad1ba7SJoel Becker mlog(ML_ERROR, 55470ad1ba7SJoel Becker "CRC32 failed: stored: %u, computed %u. Applying ECC.\n", 55570ad1ba7SJoel Becker (unsigned int)check.bc_crc32e, (unsigned int)crc); 55670ad1ba7SJoel Becker 55770ad1ba7SJoel Becker /* Ok, try ECC fixups */ 55870ad1ba7SJoel Becker for (i = 0, ecc = 0; i < nr; i++) { 55970ad1ba7SJoel Becker /* 56070ad1ba7SJoel Becker * The number of bits in a buffer is obviously b_size*8. 56170ad1ba7SJoel Becker * The offset of this buffer is b_size*i, so the bit offset 56270ad1ba7SJoel Becker * of this buffer is b_size*8*i. 56370ad1ba7SJoel Becker */ 56470ad1ba7SJoel Becker ecc = (u16)ocfs2_hamming_encode(ecc, bhs[i]->b_data, 56570ad1ba7SJoel Becker bhs[i]->b_size * 8, 56670ad1ba7SJoel Becker bhs[i]->b_size * 8 * i); 56770ad1ba7SJoel Becker } 56870ad1ba7SJoel Becker fix = ecc ^ check.bc_ecc; 56970ad1ba7SJoel Becker for (i = 0; i < nr; i++) { 57070ad1ba7SJoel Becker /* 57170ad1ba7SJoel Becker * Try the fix against each buffer. It will only affect 57270ad1ba7SJoel Becker * one of them. 57370ad1ba7SJoel Becker */ 57470ad1ba7SJoel Becker ocfs2_hamming_fix(bhs[i]->b_data, bhs[i]->b_size * 8, 57570ad1ba7SJoel Becker bhs[i]->b_size * 8 * i, fix); 57670ad1ba7SJoel Becker } 57770ad1ba7SJoel Becker 57870ad1ba7SJoel Becker /* And check the crc32 again */ 57970ad1ba7SJoel Becker for (i = 0, crc = ~0; i < nr; i++) 58070ad1ba7SJoel Becker crc = crc32_le(crc, bhs[i]->b_data, bhs[i]->b_size); 58173be192bSJoel Becker if (crc == check.bc_crc32e) { 58273be192bSJoel Becker ocfs2_blockcheck_inc_recover(stats); 58370ad1ba7SJoel Becker goto out; 58473be192bSJoel Becker } 58570ad1ba7SJoel Becker 58670ad1ba7SJoel Becker mlog(ML_ERROR, "Fixed CRC32 failed: stored: %u, computed %u\n", 58770ad1ba7SJoel Becker (unsigned int)check.bc_crc32e, (unsigned int)crc); 58870ad1ba7SJoel Becker 58970ad1ba7SJoel Becker rc = -EIO; 59070ad1ba7SJoel Becker 59170ad1ba7SJoel Becker out: 59270ad1ba7SJoel Becker bc->bc_crc32e = cpu_to_le32(check.bc_crc32e); 59370ad1ba7SJoel Becker bc->bc_ecc = cpu_to_le16(check.bc_ecc); 59470ad1ba7SJoel Becker 59570ad1ba7SJoel Becker return rc; 59670ad1ba7SJoel Becker } 59770ad1ba7SJoel Becker 59870ad1ba7SJoel Becker /* 59970ad1ba7SJoel Becker * These are the main API. They check the superblock flag before 60070ad1ba7SJoel Becker * calling the underlying operations. 60170ad1ba7SJoel Becker * 60270ad1ba7SJoel Becker * They expect the buffer(s) to be in disk format. 60370ad1ba7SJoel Becker */ 60470ad1ba7SJoel Becker void ocfs2_compute_meta_ecc(struct super_block *sb, void *data, 60570ad1ba7SJoel Becker struct ocfs2_block_check *bc) 60670ad1ba7SJoel Becker { 60770ad1ba7SJoel Becker if (ocfs2_meta_ecc(OCFS2_SB(sb))) 60870ad1ba7SJoel Becker ocfs2_block_check_compute(data, sb->s_blocksize, bc); 60970ad1ba7SJoel Becker } 61070ad1ba7SJoel Becker 61170ad1ba7SJoel Becker int ocfs2_validate_meta_ecc(struct super_block *sb, void *data, 61270ad1ba7SJoel Becker struct ocfs2_block_check *bc) 61370ad1ba7SJoel Becker { 61470ad1ba7SJoel Becker int rc = 0; 61573be192bSJoel Becker struct ocfs2_super *osb = OCFS2_SB(sb); 61670ad1ba7SJoel Becker 61773be192bSJoel Becker if (ocfs2_meta_ecc(osb)) 61873be192bSJoel Becker rc = ocfs2_block_check_validate(data, sb->s_blocksize, bc, 61973be192bSJoel Becker &osb->osb_ecc_stats); 62070ad1ba7SJoel Becker 62170ad1ba7SJoel Becker return rc; 62270ad1ba7SJoel Becker } 62370ad1ba7SJoel Becker 62470ad1ba7SJoel Becker void ocfs2_compute_meta_ecc_bhs(struct super_block *sb, 62570ad1ba7SJoel Becker struct buffer_head **bhs, int nr, 62670ad1ba7SJoel Becker struct ocfs2_block_check *bc) 62770ad1ba7SJoel Becker { 62870ad1ba7SJoel Becker if (ocfs2_meta_ecc(OCFS2_SB(sb))) 62970ad1ba7SJoel Becker ocfs2_block_check_compute_bhs(bhs, nr, bc); 63070ad1ba7SJoel Becker } 63170ad1ba7SJoel Becker 63270ad1ba7SJoel Becker int ocfs2_validate_meta_ecc_bhs(struct super_block *sb, 63370ad1ba7SJoel Becker struct buffer_head **bhs, int nr, 63470ad1ba7SJoel Becker struct ocfs2_block_check *bc) 63570ad1ba7SJoel Becker { 63670ad1ba7SJoel Becker int rc = 0; 63773be192bSJoel Becker struct ocfs2_super *osb = OCFS2_SB(sb); 63870ad1ba7SJoel Becker 63973be192bSJoel Becker if (ocfs2_meta_ecc(osb)) 64073be192bSJoel Becker rc = ocfs2_block_check_validate_bhs(bhs, nr, bc, 64173be192bSJoel Becker &osb->osb_ecc_stats); 64270ad1ba7SJoel Becker 64370ad1ba7SJoel Becker return rc; 64470ad1ba7SJoel Becker } 64570ad1ba7SJoel Becker 646