MDEV-19543 Deprecate and ignore innodb_log_checksums

The parameter innodb_log_checksums that was introduced in MariaDB 10.2.2
via mysql/mysql-server@af0acedd885eb7103e319f79d25fda7386ef1506
does not make much sense. The original motivation of introducing this
parameter (initially called innodb_log_checksum_algorithm in
mysql/mysql-server@22ba38218e1d76c24f69b5a5595ad3bf5933acb0)
was that the InnoDB redo log used the slow and insecure innodb algorithm.
With hardware or SIMD accelerated CRC-32C, there should be no reason to
allow checksums to be disabled on the redo log.

The parameter innodb_encrypt_log already implies innodb_log_checksums=ON.

Let us deprecate the parameter innodb_log_checksums and always compute
redo log checksums, even if innodb_log_checksums=OFF is specified.

An upgrade from MariaDB 10.2.2 or later will only be possible after
using the default value innodb_log_checksums=ON. If the non-default
value innodb_log_checksums=OFF was in effect when the server was shut down,
a log block checksum mismatch will be reported and the upgraded server
will fail to start up.

1 files changed, 2 insertions, 27 deletions

diff --git a/storage/innobase/include/log0log.h b/storage/innobase/include/log0log.h
index 2fb026849c1..4e51887bd5e 100644
--- a/storage/innobase/include/log0log.h
+++ b/storage/innobase/include/log0log.h
@@ -54,10 +54,6 @@ step which modifies the database, is started */
 
 typedef ulint (*log_checksum_func_t)(const byte* log_block);
 
-/** Pointer to the log checksum calculation function. Protected with
-log_sys.mutex. */
-extern log_checksum_func_t log_checksum_algorithm_ptr;
-
 /** Append a string to the log.
 @param[in]	str		string
 @param[in]	len		string length
@@ -261,28 +257,10 @@ log_block_set_data_len(
 /*===================*/
 	byte*	log_block,	/*!< in/out: log block */
 	ulint	len);		/*!< in: data length */
-/************************************************************//**
-Calculates the checksum for a log block.
-@return checksum */
-UNIV_INLINE
-ulint
-log_block_calc_checksum(
-/*====================*/
-	const byte*	block);	/*!< in: log block */
-
-/** Calculates the checksum for a log block using the CRC32 algorithm.
+/** Calculate the CRC-32C checksum of a log block.
 @param[in]	block	log block
 @return checksum */
-UNIV_INLINE
-ulint
-log_block_calc_checksum_crc32(
-	const byte*	block);
-
-/** Calculates the checksum for a log block using the "no-op" algorithm.
-@return		the calculated checksum value */
-UNIV_INLINE
-ulint
-log_block_calc_checksum_none(const byte*);
+inline ulint log_block_calc_checksum_crc32(const byte* block);
 
 /************************************************************//**
 Gets a log block checksum field value.
@@ -360,9 +338,6 @@ void
 log_refresh_stats(void);
 /*===================*/
 
-/** Whether to generate and require checksums on the redo log pages */
-extern my_bool	innodb_log_checksums;
-
 /* Values used as flags */
 #define LOG_FLUSH	7652559
 #define LOG_CHECKPOINT	78656949