1 // SPDX-License-Identifier: GPL-2.0-only
30  * d = # data bits
31  * p = # parity bits
32  * c = # total code bits (d + p)
38  * offset in the data buffer.  Since the hamming code reserves all
39  * power-of-two bits for parity, the data bit number and the code bit
40  * number are offset by all the parity bits beforehand.
42  * Recall that bit numbers in hamming code are 1-based.  This function
43  * takes the 0-based data bit from the caller.
45  * An example.  Take bit 1 of the data buffer.  1 is a power of two (2^0),
47  * 3 is not a power of two.  So bit 1 of the data buffer ends up as bit 3
51  * number of parity bits added.  This allows the function to start the
59 	 * Data bits are 0-based, but we're talking code bits, which  in calc_code_bit()
60 	 * are 1-based.  in calc_code_bit()
88  * multiple hunks just like the crc32 code.  'd' is the number of bits
97 u32 ocfs2_hamming_encode(u32 parity, void *data, unsigned int d, unsigned int nr)  in ocfs2_hamming_encode()  argument
105 	 * 1-based array, but C uses 0-based.  So 'i' is for C, and 'b' is  in ocfs2_hamming_encode()
112 	for (i = 0; (i = ocfs2_find_next_bit(data, d, i)) < d; i++)  in ocfs2_hamming_encode()
121 		 * Data bits in the resultant code are checked by  in ocfs2_hamming_encode()
122 		 * parity bits that are part of the bit number  in ocfs2_hamming_encode()
127 		 * checks bits in positions having bit k set in  in ocfs2_hamming_encode()
130 		 * bits 1000(2) = 8, 0100(2)=4 and 0001(2) = 1.  in ocfs2_hamming_encode()
139 	/* While the data buffer was treated as little endian, the  in ocfs2_hamming_encode()
144 u32 ocfs2_hamming_encode_block(void *data, unsigned int blocksize)  in ocfs2_hamming_encode_block()  argument
146 	return ocfs2_hamming_encode(0, data, blocksize * 8, 0);  in ocfs2_hamming_encode_block()
156 void ocfs2_hamming_fix(void *data, unsigned int d, unsigned int nr,  in ocfs2_hamming_fix()  argument
171 	 * nr + d is the bit right past the data hunk we're looking at.  in ocfs2_hamming_fix()
178 	 * nr is the offset in the data hunk we're starting at.  Let's  in ocfs2_hamming_fix()
189 		/* Skip past parity bits */  in ocfs2_hamming_fix()
194 		 * i is the offset in this data hunk.  in ocfs2_hamming_fix()
195 		 * nr + i is the offset in the total data buffer.  in ocfs2_hamming_fix()
203 			if (ocfs2_test_bit(i, data))  in ocfs2_hamming_fix()
204 				ocfs2_clear_bit(i, data);  in ocfs2_hamming_fix()
206 				ocfs2_set_bit(i, data);  in ocfs2_hamming_fix()
212 void ocfs2_hamming_fix_block(void *data, unsigned int blocksize,  in ocfs2_hamming_fix_block()  argument
215 	ocfs2_hamming_fix(data, blocksize * 8, 0, fix);  in ocfs2_hamming_fix_block()
225 static int blockcheck_u64_get(void *data, u64 *val)  in blockcheck_u64_get()  argument
227 	*val = *(u64 *)data;  in blockcheck_u64_get()
235 		debugfs_remove_recursive(stats->b_debug_dir);  in ocfs2_blockcheck_debug_remove()
236 		stats->b_debug_dir = NULL;  in ocfs2_blockcheck_debug_remove()
246 	stats->b_debug_dir = dir;  in ocfs2_blockcheck_debug_install()
249 			    &stats->b_check_count, &blockcheck_fops);  in ocfs2_blockcheck_debug_install()
252 			    &stats->b_failure_count, &blockcheck_fops);  in ocfs2_blockcheck_debug_install()
255 			    &stats->b_recover_count, &blockcheck_fops);  in ocfs2_blockcheck_debug_install()
269 /* Always-called wrappers for starting and stopping the debugfs files */
288 	spin_lock(&stats->b_lock);  in ocfs2_blockcheck_inc_check()
289 	stats->b_check_count++;  in ocfs2_blockcheck_inc_check()
290 	new_count = stats->b_check_count;  in ocfs2_blockcheck_inc_check()
291 	spin_unlock(&stats->b_lock);  in ocfs2_blockcheck_inc_check()
304 	spin_lock(&stats->b_lock);  in ocfs2_blockcheck_inc_failure()
305 	stats->b_failure_count++;  in ocfs2_blockcheck_inc_failure()
306 	new_count = stats->b_failure_count;  in ocfs2_blockcheck_inc_failure()
307 	spin_unlock(&stats->b_lock);  in ocfs2_blockcheck_inc_failure()
320 	spin_lock(&stats->b_lock);  in ocfs2_blockcheck_inc_recover()
321 	stats->b_recover_count++;  in ocfs2_blockcheck_inc_recover()
322 	new_count = stats->b_recover_count;  in ocfs2_blockcheck_inc_recover()
323 	spin_unlock(&stats->b_lock);  in ocfs2_blockcheck_inc_recover()
332  * These are the low-level APIs for using the ocfs2_block_check structure.
337  * data is the block to be checked.  bc is a pointer to the
340  * bc should be a pointer inside data, as the function will
342  * bc does not point inside data, the caller must make sure any inline
345  * The data buffer must be in on-disk endian (little endian for ocfs2).
346  * bc will be filled with little-endian values and will be ready to go to
349 void ocfs2_block_check_compute(void *data, size_t blocksize,  in ocfs2_block_check_compute()  argument
357 	crc = crc32_le(~0, data, blocksize);  in ocfs2_block_check_compute()
358 	ecc = ocfs2_hamming_encode_block(data, blocksize);  in ocfs2_block_check_compute()
362 	 * larger than 16 bits.  in ocfs2_block_check_compute()
366 	bc->bc_crc32e = cpu_to_le32(crc);  in ocfs2_block_check_compute()
367 	bc->bc_ecc = cpu_to_le16((u16)ecc);  in ocfs2_block_check_compute()
373  * If bc is not a pointer inside data, the caller must have zeroed any
376  * Again, the data passed in should be the on-disk endian.
378 int ocfs2_block_check_validate(void *data, size_t blocksize,  in ocfs2_block_check_validate()  argument
389 	bc_crc32e = le32_to_cpu(bc->bc_crc32e);  in ocfs2_block_check_validate()
390 	bc_ecc = le16_to_cpu(bc->bc_ecc);  in ocfs2_block_check_validate()
394 	/* Fast path - if the crc32 validates, we're good to go */  in ocfs2_block_check_validate()
395 	crc = crc32_le(~0, data, blocksize);  in ocfs2_block_check_validate()
405 	ecc = ocfs2_hamming_encode_block(data, blocksize);  in ocfs2_block_check_validate()
406 	ocfs2_hamming_fix_block(data, blocksize, ecc ^ bc_ecc);  in ocfs2_block_check_validate()
409 	crc = crc32_le(~0, data, blocksize);  in ocfs2_block_check_validate()
418 	rc = -EIO;  in ocfs2_block_check_validate()
421 	bc->bc_crc32e = cpu_to_le32(bc_crc32e);  in ocfs2_block_check_validate()
422 	bc->bc_ecc = cpu_to_le16(bc_ecc);  in ocfs2_block_check_validate()
432  * bc should be a pointer inside data, as the function will
434  * bc does not point inside data, the caller must make sure any inline
437  * The data buffer must be in on-disk endian (little endian for ocfs2).
438  * bc will be filled with little-endian values and will be ready to go to
455 		crc = crc32_le(crc, bhs[i]->b_data, bhs[i]->b_size);  in ocfs2_block_check_compute_bhs()
457 		 * The number of bits in a buffer is obviously b_size*8.  in ocfs2_block_check_compute_bhs()
461 		ecc = (u16)ocfs2_hamming_encode(ecc, bhs[i]->b_data,  in ocfs2_block_check_compute_bhs()
462 						bhs[i]->b_size * 8,  in ocfs2_block_check_compute_bhs()
463 						bhs[i]->b_size * 8 * i);  in ocfs2_block_check_compute_bhs()
468 	 * larger than 16 bits.  in ocfs2_block_check_compute_bhs()
472 	bc->bc_crc32e = cpu_to_le32(crc);  in ocfs2_block_check_compute_bhs()
473 	bc->bc_ecc = cpu_to_le16((u16)ecc);  in ocfs2_block_check_compute_bhs()
480  * inside data, the caller must have zeroed any inline
483  * Again, the data passed in should be the on-disk endian.
501 	bc_crc32e = le32_to_cpu(bc->bc_crc32e);  in ocfs2_block_check_validate_bhs()
502 	bc_ecc = le16_to_cpu(bc->bc_ecc);  in ocfs2_block_check_validate_bhs()
506 	/* Fast path - if the crc32 validates, we're good to go */  in ocfs2_block_check_validate_bhs()
508 		crc = crc32_le(crc, bhs[i]->b_data, bhs[i]->b_size);  in ocfs2_block_check_validate_bhs()
520 		 * The number of bits in a buffer is obviously b_size*8.  in ocfs2_block_check_validate_bhs()
524 		ecc = (u16)ocfs2_hamming_encode(ecc, bhs[i]->b_data,  in ocfs2_block_check_validate_bhs()
525 						bhs[i]->b_size * 8,  in ocfs2_block_check_validate_bhs()
526 						bhs[i]->b_size * 8 * i);  in ocfs2_block_check_validate_bhs()
534 		ocfs2_hamming_fix(bhs[i]->b_data, bhs[i]->b_size * 8,  in ocfs2_block_check_validate_bhs()
535 				  bhs[i]->b_size * 8 * i, fix);  in ocfs2_block_check_validate_bhs()
540 		crc = crc32_le(crc, bhs[i]->b_data, bhs[i]->b_size);  in ocfs2_block_check_validate_bhs()
549 	rc = -EIO;  in ocfs2_block_check_validate_bhs()
552 	bc->bc_crc32e = cpu_to_le32(bc_crc32e);  in ocfs2_block_check_validate_bhs()
553 	bc->bc_ecc = cpu_to_le16(bc_ecc);  in ocfs2_block_check_validate_bhs()
564 void ocfs2_compute_meta_ecc(struct super_block *sb, void *data,  in ocfs2_compute_meta_ecc()  argument
568 		ocfs2_block_check_compute(data, sb->s_blocksize, bc);  in ocfs2_compute_meta_ecc()
571 int ocfs2_validate_meta_ecc(struct super_block *sb, void *data,  in ocfs2_validate_meta_ecc()  argument
578 		rc = ocfs2_block_check_validate(data, sb->s_blocksize, bc,  in ocfs2_validate_meta_ecc()
579 						&osb->osb_ecc_stats);  in ocfs2_validate_meta_ecc()
601 						    &osb->osb_ecc_stats);  in ocfs2_validate_meta_ecc_bhs()