WIP: Introduce separate ib_logdata file

The file ib_logfile0 used to consist of a 2048-byte header
and a fixed-size portion of log records written in circular fashion.

We are introducing a separate ib_logdata for the circular log,
while ib_logfile0 will (eventually) an append-only file comprising
a header (facilitating upgrade/downgrade checks) and records that
identify data files and checkpoints.

FIXME: Upgrade from earlier version is broken (in addition to
crash recovery being broken).

create_data_file(): create ib_logdata which should have
a size of srv_log_file_size.

recv_sys_t::upgrade_file_format_to_10_6_if_needed(): not finished
bacause more file format changes are coming.

log_t::file::lsn_offset: start from 0 (no header in file)

log_t::file::data_fd: this one is ib_logdata

16 files changed, 355 insertions, 105 deletions

diff --git a/extra/mariabackup/xtrabackup.cc b/extra/mariabackup/xtrabackup.cc
index e57454ef19f..bdc2fb5568a 100644
--- a/extra/mariabackup/xtrabackup.cc
+++ b/extra/mariabackup/xtrabackup.cc
@@ -4295,9 +4295,9 @@ static bool xtrabackup_backup_low()
 		if (recv_find_max_checkpoint(&max_cp_field) == DB_SUCCESS
 		    && log_sys.log.format != 0) {
 			if (max_cp_field == LOG_CHECKPOINT_1) {
-				log_sys.log.read(max_cp_field,
-						 {log_sys.checkpoint_buf,
-						  OS_FILE_LOG_BLOCK_SIZE});
+				log_sys.log.data_read(max_cp_field,
+						      {log_sys.checkpoint_buf,
+						       OS_FILE_LOG_BLOCK_SIZE});
 			}
 			metadata_to_lsn = mach_read_from_8(
 				log_sys.checkpoint_buf + LOG_CHECKPOINT_LSN);
@@ -4461,7 +4461,7 @@ fail:
 
 	log_sys.create();
 	log_sys.log.create();
-	log_sys.log.open_file(get_log_file_path());
+	log_sys.log.open_files(get_log_file_path());
 
 	/* create extra LSN dir if it does not exist. */
 	if (xtrabackup_extra_lsndir
@@ -4519,7 +4519,7 @@ free_and_fail:
 	checkpoint_lsn_start = log_sys.log.get_lsn();
 	checkpoint_no_start = log_sys.next_checkpoint_no;
 
-	log_sys.log.read(max_cp_field, {buf, OS_FILE_LOG_BLOCK_SIZE});
+	log_sys.log.main_read(max_cp_field, {buf, OS_FILE_LOG_BLOCK_SIZE});
 
 	if (checkpoint_no_start != mach_read_from_8(buf + LOG_CHECKPOINT_NO)
 	    || checkpoint_lsn_start
@@ -4536,19 +4536,28 @@ free_and_fail:
 		goto free_and_fail;
 	}
 
-	/* open the log file */
+	/* open the log data file */
 	memset(&stat_info, 0, sizeof(MY_STAT));
-	dst_log_file = ds_open(ds_redo, LOG_FILE_NAME, &stat_info);
+	dst_log_file = ds_open(ds_redo, LOG_DATA_FILE_NAME, &stat_info);
 	if (dst_log_file == NULL) {
 		msg("Error: failed to open the target stream for '%s'.",
+		    LOG_DATA_FILE_NAME);
+		goto fail;
+	}
+
+	memset(&stat_info, 0, sizeof(MY_STAT));
+	ds_file_t *dst_log_main_file=
+		ds_open(ds_redo, LOG_FILE_NAME, &stat_info);
+	if (dst_log_main_file == nullptr) {
+		msg("Error: failed to open the target stream for '%s'.",
 		    LOG_FILE_NAME);
 		goto free_and_fail;
 	}
 
 	/* label it */
 	byte* log_hdr_buf = static_cast<byte*>(
-		aligned_malloc(LOG_FILE_HDR_SIZE, OS_FILE_LOG_BLOCK_SIZE));
-	memset(log_hdr_buf, 0, LOG_FILE_HDR_SIZE);
+		aligned_malloc(LOG_MAIN_FILE_SIZE, LOG_MAIN_FILE_SIZE));
+	memset(log_hdr_buf, 0, LOG_MAIN_FILE_SIZE);
 
 	byte *log_hdr_field = log_hdr_buf;
 	mach_write_to_4(LOG_HEADER_FORMAT + log_hdr_field, log_sys.log.format);
@@ -4571,19 +4580,24 @@ free_and_fail:
 	/* Adjust the checkpoint page. */
 	memcpy(log_hdr_field, log_sys.checkpoint_buf, OS_FILE_LOG_BLOCK_SIZE);
 	mach_write_to_8(log_hdr_field + LOG_CHECKPOINT_OFFSET,
-		(checkpoint_lsn_start & (OS_FILE_LOG_BLOCK_SIZE - 1))
-		| LOG_FILE_HDR_SIZE);
+		(checkpoint_lsn_start & (OS_FILE_LOG_BLOCK_SIZE - 1)));
 	log_block_set_checksum(log_hdr_field,
 			log_block_calc_checksum_crc32(log_hdr_field));
 
 	/* Write log header*/
-	if (ds_write(dst_log_file, log_hdr_buf, LOG_FILE_HDR_SIZE)) {
+	if (ds_write(dst_log_file, log_hdr_buf, LOG_MAIN_FILE_SIZE)) {
 		msg("error: write to logfile failed");
 		aligned_free(log_hdr_buf);
 		goto free_and_fail;
 	}
 
 	aligned_free(log_hdr_buf);
+
+	if (int err = ds_close(dst_log_main_file)) {
+		msg("error while closing %s: %d", LOG_FILE_NAME, err);
+	}
+	dst_log_main_file = nullptr;
+
 	log_copying_running = true;
 	/* start io throttle */
 	if(xtrabackup_throttle) {
diff --git a/mysql-test/suite/encryption/r/innodb_encrypt_log.result b/mysql-test/suite/encryption/r/innodb_encrypt_log.result
index b436435090b..6bde3174ebd 100644
--- a/mysql-test/suite/encryption/r/innodb_encrypt_log.result
+++ b/mysql-test/suite/encryption/r/innodb_encrypt_log.result
@@ -46,8 +46,10 @@ INSERT INTO t0 VALUES(NULL, 5, 5, 'public', 'gossip');
 # Kill the server
 # ib_logfile0 expecting NOT FOUND
 NOT FOUND /private|secret|sacr(ed|ament)|success|story|secur(e|ity)/ in ib_logfile0
-# ib_logfile0 expecting FOUND
-FOUND 1 /(public|gossip).*/ in ib_logfile0
+# ib_logfile0 expecting NOT FOUND
+NOT FOUND /(public|gossip).*/ in ib_logfile0
+# ib_logdata expecting FOUND
+FOUND 1 /(public|gossip).*/ in ib_logdata
 # ibdata1 expecting NOT FOUND
 NOT FOUND /private|secret|sacr(ed|ament)|success|story|secur(e|ity)|public|gossip/ in ibdata1
 # t0.ibd expecting NOT FOUND
diff --git a/mysql-test/suite/encryption/t/innodb_encrypt_log.test b/mysql-test/suite/encryption/t/innodb_encrypt_log.test
index 1d016be73c8..4fc09621122 100644
--- a/mysql-test/suite/encryption/t/innodb_encrypt_log.test
+++ b/mysql-test/suite/encryption/t/innodb_encrypt_log.test
@@ -73,9 +73,12 @@ INSERT INTO t0 VALUES(NULL, 5, 5, 'public', 'gossip');
 -- let SEARCH_FILE=$MYSQLD_DATADIR/ib_logfile0
 -- source include/search_pattern_in_file.inc
 --let SEARCH_PATTERN=(public|gossip).*
---echo # ib_logfile0 expecting FOUND
+--echo # ib_logfile0 expecting NOT FOUND
 -- let SEARCH_FILE=$MYSQLD_DATADIR/ib_logfile0
 -- source include/search_pattern_in_file.inc
+--echo # ib_logdata expecting FOUND
+-- let SEARCH_FILE=$MYSQLD_DATADIR/ib_logdata
+-- source include/search_pattern_in_file.inc
 
 --let SEARCH_PATTERN=private|secret|sacr(ed|ament)|success|story|secur(e|ity)|public|gossip
 --echo # ibdata1 expecting NOT FOUND
diff --git a/mysql-test/suite/innodb/include/log_file_cleanup.inc b/mysql-test/suite/innodb/include/log_file_cleanup.inc
index 80ce1df0c97..6f3bd8e525b 100644
--- a/mysql-test/suite/innodb/include/log_file_cleanup.inc
+++ b/mysql-test/suite/innodb/include/log_file_cleanup.inc
@@ -5,10 +5,12 @@
 --list_files $bugdir
 --remove_files_wildcard $bugdir ibdata*
 --remove_files_wildcard $bugdir ib_logfile*
+--remove_files_wildcard $bugdir ib_logdata
 --remove_files_wildcard $bugdir undo00*
 --copy_file $bugdir/bak_ibdata1 $bugdir/ibdata1
 --copy_file $bugdir/bak_ibdata2 $bugdir/ibdata2
 --copy_file $bugdir/bak_ib_logfile0 $bugdir/ib_logfile0
+--copy_file $bugdir/bak_ib_logdata $bugdir/ib_logdata
 --copy_file $bugdir/bak_undo001 $bugdir/undo001
 --copy_file $bugdir/bak_undo002 $bugdir/undo002
 --copy_file $bugdir/bak_undo003 $bugdir/undo003
diff --git a/mysql-test/suite/innodb/r/log_file.result b/mysql-test/suite/innodb/r/log_file.result
index 10479e5004a..ff0b5b78115 100644
--- a/mysql-test/suite/innodb/r/log_file.result
+++ b/mysql-test/suite/innodb/r/log_file.result
@@ -9,6 +9,7 @@ AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /\[ERROR\] InnoDB: Could not create undo tablespace '.*undo002'/ in mysqld.1.err
 # Remove  undo001,undo002,ibdata1,ibdata2,ib_logfile101
+ib_logdata
 # Start mysqld with non existent innodb_log_group_home_dir
 # restart: --innodb-log-group-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-data-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-directory=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-logs=20 --innodb-undo-tablespaces=3 --innodb-data-file-path=ibdata1:16M;ibdata2:10M:autoextend --innodb_log_group_home_dir=/path/to/non-existent/
 SELECT * FROM INFORMATION_SCHEMA.ENGINES
@@ -17,6 +18,7 @@ AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /File .path.to.non-existent.*ib_logfile101: 'create' returned OS error \d+/ in mysqld.1.err
 # Remove ibdata1 & ibdata2
+ib_logdata
 # Successfully let InnoDB create tablespaces
 # restart: --innodb-log-group-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-data-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-directory=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-logs=20 --innodb-undo-tablespaces=3 --innodb-data-file-path=ibdata1:16M;ibdata2:10M:autoextend
 SELECT COUNT(*) `1` FROM INFORMATION_SCHEMA.ENGINES
@@ -32,6 +34,7 @@ WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /The data file '.*ibdata1' was not found but one of the other data files '.*ibdata2' exists/ in mysqld.1.err
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -39,6 +42,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata2
 undo001
@@ -52,6 +56,7 @@ AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /InnoDB: Tablespace size stored in header is \d+ pages, but the sum of data file sizes is \d+ pages/ in mysqld.1.err
 FOUND 1 /InnoDB: Cannot start InnoDB. The tail of the system tablespace is missing/ in mysqld.1.err
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -59,6 +64,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
@@ -66,6 +72,7 @@ undo001
 undo002
 undo003
 # 3. Without ibdata1 & ibdata2
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -73,6 +80,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 undo001
 undo002
@@ -83,6 +91,7 @@ WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /InnoDB: undo tablespace .*undo001.* exists\. Creating system tablespace with existing undo tablespaces is not supported\. Please delete all undo tablespaces before creating new system tablespace\./ in mysqld.1.err
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -90,11 +99,13 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 undo001
 undo002
 undo003
 # 4. Without ibdata*, ib_logfile* and with undo00*
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -110,6 +121,7 @@ SELECT * FROM INFORMATION_SCHEMA.ENGINES
 WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -121,6 +133,7 @@ undo001
 undo002
 undo003
 # 5. Without ibdata*,ib_logfile* files & Without undo002
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -135,6 +148,7 @@ SELECT * FROM INFORMATION_SCHEMA.ENGINES
 WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -145,6 +159,7 @@ ib_buffer_pool
 undo001
 undo003
 # 6. Without ibdata*,ib_logfile* files & Without undo001, undo002
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -159,6 +174,7 @@ WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /undo tablespace .*undo003.* exists\. Creating system tablespace with existing undo tablespaces is not supported\. Please delete all undo tablespaces before creating new system tablespace\./ in mysqld.1.err
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -168,6 +184,7 @@ bak_undo003
 ib_buffer_pool
 undo003
 # 7. With ibdata files & Without undo002
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -175,6 +192,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
@@ -186,6 +204,7 @@ WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /InnoDB: Expected to open innodb_undo_tablespaces=3 but was able to find only 1/ in mysqld.1.err
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -193,12 +212,14 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
 undo001
 undo003
 # 8. With ibdata files & Without undo001, undo002
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -206,6 +227,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
@@ -216,6 +238,7 @@ WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /InnoDB: Expected to open innodb_undo_tablespaces=3 but was able to find only 0/ in mysqld.1.err
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -223,11 +246,13 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
 undo003
 # 9. Without ibdata*, without undo*
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -235,6 +260,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 # restart: --innodb-log-group-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-data-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-directory=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-logs=20 --innodb-undo-tablespaces=3 --innodb-data-file-path=ibdata1:16M;ibdata2:10M:autoextend
 SELECT * FROM INFORMATION_SCHEMA.ENGINES
@@ -242,6 +268,7 @@ WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 FOUND 1 /redo log file .*ib_logfile0.* exists\. Creating system tablespace with existing redo log file is not recommended\. Please delete redo log file before creating new system tablespace\./ in mysqld.1.err
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -249,6 +276,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 # 10. With ibdata*, without ib_logfile0
 # restart: --innodb-log-group-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-data-home-dir=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-directory=MYSQLTEST_VARDIR/tmp/log_file --innodb-undo-logs=20 --innodb-undo-tablespaces=3 --innodb-data-file-path=ibdata1:16M;ibdata2:10M:autoextend
@@ -257,6 +285,7 @@ WHERE engine = 'innodb'
 AND support IN ('YES', 'DEFAULT', 'ENABLED');
 ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
 InnoDB	YES	Supports transactions, row-level locking, foreign keys and encryption for tables	YES	YES	YES
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -264,6 +293,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
@@ -271,6 +301,7 @@ undo001
 undo002
 undo003
 # 11. With ibdata*
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -278,6 +309,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
@@ -293,6 +325,7 @@ AND support IN ('YES', 'DEFAULT', 'ENABLED');
 NOT FOUND /Resizing redo log from 1\*\d+ to 3\*\d+ bytes; LSN=\d+/ in mysqld.1.err
 # restart
 # Cleanup
+bak_ib_logdata
 bak_ib_logfile0
 bak_ibdata1
 bak_ibdata2
@@ -300,6 +333,7 @@ bak_undo001
 bak_undo002
 bak_undo003
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 ibdata2
diff --git a/mysql-test/suite/innodb/r/row_format_redundant.result b/mysql-test/suite/innodb/r/row_format_redundant.result
index f354666f645..bccd81d3164 100644
--- a/mysql-test/suite/innodb/r/row_format_redundant.result
+++ b/mysql-test/suite/innodb/r/row_format_redundant.result
@@ -78,6 +78,7 @@ DROP TABLE t2,t3;
 FOUND 5 /\[ERROR\] InnoDB: Table test/t1 in InnoDB data dictionary contains invalid flags\. SYS_TABLES\.TYPE=1 SYS_TABLES\.MIX_LEN=511\b/ in mysqld.1.err
 # restart
 ib_buffer_pool
+ib_logdata
 ib_logfile0
 ibdata1
 db.opt
diff --git a/mysql-test/suite/innodb/r/table_flags.result b/mysql-test/suite/innodb/r/table_flags.result
index ce71d9b022d..7f5b91588c8 100644
--- a/mysql-test/suite/innodb/r/table_flags.result
+++ b/mysql-test/suite/innodb/r/table_flags.result
@@ -172,6 +172,7 @@ SELECT * FROM tp;
 a
 DROP TABLE tr,tc,td,tz,tp;
 # restart
+ib_logdata
 ib_logfile0
 ibdata1
 sys_tables.bin
diff --git a/mysql-test/suite/innodb/t/log_file.test b/mysql-test/suite/innodb/t/log_file.test
index f03bce804f6..eb772cf23db 100644
--- a/mysql-test/suite/innodb/t/log_file.test
+++ b/mysql-test/suite/innodb/t/log_file.test
@@ -79,6 +79,7 @@ eval $check_yes_innodb;
 --copy_file $bugdir/ibdata1 $bugdir/bak_ibdata1
 --copy_file $bugdir/ibdata2 $bugdir/bak_ibdata2
 --copy_file $bugdir/ib_logfile0 $bugdir/bak_ib_logfile0
+--copy_file $bugdir/ib_logdata $bugdir/bak_ib_logdata
 --copy_file $bugdir/undo001 $bugdir/bak_undo001
 --copy_file $bugdir/undo002 $bugdir/bak_undo002
 --copy_file $bugdir/undo003 $bugdir/bak_undo003
@@ -124,6 +125,7 @@ let SEARCH_PATTERN=InnoDB: undo tablespace .*undo001.* exists\. Creating system
 --echo # 4. Without ibdata*, ib_logfile* and with undo00*
 --remove_files_wildcard $bugdir ibdata*
 --remove_files_wildcard $bugdir ib_logfile*
+--remove_files_wildcard $bugdir ib_logdata
 --list_files $bugdir
 --source include/start_mysqld.inc
 eval $check_no_innodb;
@@ -135,6 +137,7 @@ eval $check_no_innodb;
 --echo # 5. Without ibdata*,ib_logfile* files & Without undo002
 --remove_files_wildcard $bugdir ibdata*
 --remove_files_wildcard $bugdir ib_logfile*
+--remove_files_wildcard $bugdir ib_logdata
 --remove_file $bugdir/undo002
 --list_files $bugdir
 --source include/start_mysqld.inc
@@ -148,6 +151,7 @@ eval $check_no_innodb;
 # and with undo003
 --remove_files_wildcard $bugdir ibdata*
 --remove_files_wildcard $bugdir ib_logfile*
+--remove_files_wildcard $bugdir ib_logdata
 --remove_file $bugdir/undo001
 --remove_file $bugdir/undo002
 --list_files $bugdir
@@ -199,6 +203,7 @@ let SEARCH_PATTERN=redo log file .*ib_logfile0.* exists\. Creating system tables
 
 --echo # 10. With ibdata*, without ib_logfile0
 --remove_file $bugdir/ib_logfile0
+--remove_file $bugdir/ib_logdata
 
 --source include/start_mysqld.inc
 eval $check_no_innodb;
diff --git a/mysql-test/suite/innodb_fts/disabled.def b/mysql-test/suite/innodb_fts/disabled.def
index 92e1ad34c9c..a1e4ac99eda 100644
--- a/mysql-test/suite/innodb_fts/disabled.def
+++ b/mysql-test/suite/innodb_fts/disabled.def
@@ -1,2 +1,3 @@
 crash_recovery : MDEV-14425 breaks recovery
 sync : MDEV-14425 breaks recovery
+innodb-fts-ddl : MDEV-14425 breaks recovery
diff --git a/mysql-test/suite/mariabackup/disabled.def b/mysql-test/suite/mariabackup/disabled.def
index fcf7ee167fd..b81aa10f00d 100644
--- a/mysql-test/suite/mariabackup/disabled.def
+++ b/mysql-test/suite/mariabackup/disabled.def
@@ -1,6 +1,7 @@
 log_page_corruption : MDEV-26210
 apply-log-only : MDEV-14425 breaks recovery
 apply-log-only-incr : MDEV-14425 breaks recovery
+backup_grants : MDEV-14425 breaks recovery
 backup_ssl : MDEV-14425 breaks recovery
 big_innodb_log : MDEV-14425 breaks recovery
 binlog : MDEV-14425 breaks recovery
@@ -8,18 +9,23 @@ create_during_backup : MDEV-14425 breaks recovery
 create_with_data_directory_during_backup : MDEV-14425 breaks recovery
 data_directory : MDEV-14425 breaks recovery
 drop_table_during_backup : MDEV-14425 breaks recovery
+encrypted_page_corruption : MDEV-14425 breaks recovery
 extra_lsndir : MDEV-14425 breaks recovery
+extra_lsndir_stream : MDEV-14425 breaks recovery
 full_backup : MDEV-14425 breaks recovery
 huge_lsn : MDEV-14425 breaks recovery
 incremental_backup : MDEV-14425 breaks recovery
 incremental_ddl_before_backup : MDEV-14425 breaks recovery
 incremental_ddl_during_backup : MDEV-14425 breaks recovery
 incremental_encrypted : MDEV-14425 breaks recovery
+innodb_redo_overwrite : MDEV-14425 breaks recovery
 lock_ddl_per_table : MDEV-14425 breaks recovery
 log_checksum_mismatch : MDEV-14425 breaks recovery
 log_page_corruption : MDEV-14425 breaks recovery
 mdev-14447 : MDEV-14425 breaks recovery
+mdev-18438 : MDEV-14425 breaks recovery
 nolock_ddl_during_backup_end : MDEV-14425 breaks recovery
+options_check : MDEV-14425 breaks recovery
 page_compression_level : MDEV-14425 breaks recovery
 partial : MDEV-14425 breaks recovery
 partial_exclude : MDEV-14425 breaks recovery
@@ -28,6 +34,8 @@ partition_partial : MDEV-14425 breaks recovery
 recreate_table_during_backup : MDEV-14425 breaks recovery
 rename_during_backup : MDEV-14425 breaks recovery
 rename_during_mdl_lock : MDEV-14425 breaks recovery
+rpl_slave_info : MDEV-14425 breaks recovery
+small_ibd : MDEV-14425 breaks recovery
 system_versioning : MDEV-14425 breaks recovery
 truncate_during_backup : MDEV-14425 breaks recovery
 undo_space_id : MDEV-14425 breaks recovery
@@ -35,6 +43,7 @@ unsupported_redo : MDEV-14425 breaks recovery
 xb_compressed_encrypted : MDEV-14425 breaks recovery
 xb_file_key_management : MDEV-14425 breaks recovery
 xb_fulltext_encrypted : MDEV-14425 breaks recovery
+xb_history : MDEV-14425 breaks recovery
 xb_page_compress : MDEV-14425 breaks recovery
 xb_partition : MDEV-14425 breaks recovery
 xbstream : MDEV-14425 breaks recovery
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index ecaf89fe259..c743df09bad 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -18009,7 +18009,6 @@ checkpoint_now_set(THD*, st_mysql_sys_var*, void*, const void* save)
 			       std::memory_order_acquire)
 		       < (lsn= log_sys.get_lsn(std::memory_order_acquire))) {
 			log_make_checkpoint();
-			log_sys.log.flush();
 		}
 
 		if (dberr_t err = fil_write_flushed_lsn(lsn)) {
diff --git a/storage/innobase/include/log0log.h b/storage/innobase/include/log0log.h
index ca792f9e439..366c03ebfcb 100644
--- a/storage/innobase/include/log0log.h
+++ b/storage/innobase/include/log0log.h
@@ -46,6 +46,12 @@ using st_::span;
 static const char LOG_FILE_NAME_PREFIX[] = "ib_logfile";
 static const char LOG_FILE_NAME[] = "ib_logfile0";
 
+/** this is where redo log data is stored (no header, no checkpoints) */
+static const char LOG_DATA_FILE_NAME[] = "ib_logdata";
+
+/** creates LOG_DATA_FILE_NAME with specified size */
+dberr_t create_data_file(os_offset_t size);
+
 /** Composes full path for a redo log file
 @param[in]	filename	name of the redo log file
 @return path with log file name*/
@@ -346,7 +352,8 @@ or the MySQL version that created the redo log file. */
 #define LOG_CHECKPOINT_2	(3 * OS_FILE_LOG_BLOCK_SIZE)
 					/* second checkpoint field in the log
 					header */
-#define LOG_FILE_HDR_SIZE	(4 * OS_FILE_LOG_BLOCK_SIZE)
+/** size of LOG_FILE_NAME (header + checkpoints */
+constexpr size_t LOG_MAIN_FILE_SIZE= 4 * OS_FILE_LOG_BLOCK_SIZE;
 
 /** Memory mapped file */
 class mapped_file_t
@@ -506,42 +513,49 @@ public:
     lsn_t				lsn;
     /** the byte offset of the above lsn */
     lsn_t				lsn_offset;
-    /** log file */
+    /** main log file */
     log_file_t				fd;
+    /** log data file */
+    log_file_t				data_fd;
 
   public:
     /** used only in recovery: recovery scan succeeded up to this
     lsn in this log group */
     lsn_t				scanned_lsn;
 
-    /** opens log file which must be closed prior this call */
-    void open_file(std::string path);
+    /** opens log files which must be closed prior this call */
+    void open_files(std::string path);
     /** writes header */
     void write_header_durable(lsn_t lsn);
     /** opens log file which must be closed prior this call */
     dberr_t rename(std::string path) { return fd.rename(path); }
-    /** reads buffer from log file
+    /** read from the main log file
     @param[in]	offset		offset in log file
     @param[in]	buf		buffer where to read */
-    void read(os_offset_t offset, span<byte> buf);
-    /** Tells whether writes require calling flush() */
-    bool writes_are_durable() const noexcept;
+    void main_read(os_offset_t offset, span<byte> buf);
     /** writes buffer to log file
     @param[in]	offset		offset in log file
     @param[in]	buf		buffer from which to write */
-    void write(os_offset_t offset, span<byte> buf);
+    void main_write_durable(os_offset_t offset, span<byte> buf);
+    /** closes log files */
+    void close_files();
+
+    /** check that log data file is opened */
+    bool data_is_opened() const  { return data_fd.is_opened(); }
+    /** reads from data file */
+    void data_read(os_offset_t offset, span<byte> buf);
+    /** Tells whether writes require calling flush_data_only() */
+    bool data_writes_are_durable() const noexcept;
+    /** writes to data file */
+    void data_write(os_offset_t offset, span<byte> buf);
     /** flushes OS page cache (excluding metadata!) for log file */
     void flush();
-    /** closes log file */
-    void close_file();
 
     /** @return whether the redo log is encrypted */
     bool is_encrypted() const { return format & FORMAT_ENCRYPTED; }
     /** @return whether the redo log is in the physical format */
     bool is_physical() const
     { return (format & ~FORMAT_ENCRYPTED) == FORMAT_10_5; }
-    /** @return capacity in bytes */
-    lsn_t capacity() const{ return file_size - LOG_FILE_HDR_SIZE; }
     /** Calculate the offset of a log sequence number.
     @param[in]	lsn	log sequence number
     @return offset within the log */
@@ -567,7 +581,7 @@ public:
     void create();
 
     /** Close the redo log buffer. */
-    void close() { close_file(); }
+    void close() { close_files(); }
     void set_lsn(lsn_t a_lsn);
     lsn_t get_lsn() const { return lsn; }
     void set_lsn_offset(lsn_t a_lsn);
@@ -723,16 +737,17 @@ inline lsn_t log_t::file::calc_lsn_offset(lsn_t lsn) const
 #ifdef SAFE_MUTEX
   ut_ad(mysql_mutex_is_owner(&log_sys.mutex) || log_write_lock_own());
 #endif /* SAFE_MUTEX */
-  const lsn_t size = capacity();
+  const lsn_t size= file_size;
   lsn_t l= lsn - this->lsn;
-  if (longlong(l) < 0) {
-	  l = lsn_t(-longlong(l)) % size;
-	  l = size - l;
+  if (longlong(l) < 0)
+  {
+    l= lsn_t(-longlong(l)) % size;
+    l= size - l;
   }
 
-  l+= lsn_offset - LOG_FILE_HDR_SIZE * (1 + lsn_offset / file_size);
-  l %= size;
-  return l + LOG_FILE_HDR_SIZE * (1 + l / (file_size - LOG_FILE_HDR_SIZE));
+  l+= lsn_offset;
+  l%= size;
+  return l;
 }
 
 inline void log_t::file::set_lsn(lsn_t a_lsn)
diff --git a/storage/innobase/include/log0recv.h b/storage/innobase/include/log0recv.h
index b776c82af62..0b686ffbe54 100644
--- a/storage/innobase/include/log0recv.h
+++ b/storage/innobase/include/log0recv.h
@@ -279,6 +279,12 @@ public:
   /** Last added LSN to pages. */
   lsn_t last_stored_lsn= 0;
 
+  /** this block should be copied to LOG_DATA_FILE_NAME on upgrade from old
+  file format */
+  void set_block_to_copy(os_offset_t off);
+  /** upgrades file format if needed */
+  dberr_t upgrade_file_format_to_10_6_if_needed();
+
   void read(os_offset_t offset, span<byte> buf);
   inline size_t files_size();
   void close_files() { files.clear(); files.shrink_to_fit(); }
@@ -302,6 +308,11 @@ private:
   from before MariaDB Server 10.5.1) */
   std::vector<log_file_t> files;
 
+  /** Last checkpoint in empty pre-10.5 log files points to this block.
+  In old file format it's never 0, because old redo log file has a header. */
+  os_offset_t block_to_copy_when_upgrading_file_format= 0;
+
+  /** used for laziness */
   void open_log_files_if_needed();
 
   /** Base node of the redo block list.
diff --git a/storage/innobase/log/log0log.cc b/storage/innobase/log/log0log.cc
index 4efe3a509eb..b17bc5933b8 100644
--- a/storage/innobase/log/log0log.cc
+++ b/storage/innobase/log/log0log.cc
@@ -136,7 +136,7 @@ log_set_capacity(ulonglong file_size)
 	lsn_t		margin;
 	ulint		free;
 
-	lsn_t smallest_capacity = file_size - LOG_FILE_HDR_SIZE;
+	lsn_t smallest_capacity = file_size;
 	/* Add extra safety */
 	smallest_capacity -= smallest_capacity / 10;
 
@@ -440,11 +440,24 @@ dberr_t log_file_t::flush() noexcept
   return m_file->flush();
 }
 
-void log_t::file::open_file(std::string path)
+void log_t::file::open_files(std::string path)
 {
   fd= log_file_t(std::move(path));
   if (const dberr_t err= fd.open(srv_read_only_mode))
     ib::fatal() << "open(" << fd.get_path() << ") returned " << err;
+
+  data_fd= log_file_t(get_log_file_path(LOG_DATA_FILE_NAME));
+  bool exists;
+  os_file_type_t type;
+  os_file_status(data_fd.get_path().c_str(), &exists, &type);
+  if (exists)
+  {
+    if (const dberr_t err= data_fd.open(srv_read_only_mode))
+      ib::fatal() << "open(" << data_fd.get_path() << ") returned " << err;
+
+    srv_log_file_size=
+        os_file_get_size(data_fd.get_path().c_str()).m_total_size;
+  }
 }
 
 /** Update the log block checksum. */
@@ -474,23 +487,16 @@ void log_t::file::write_header_durable(lsn_t lsn)
 
   DBUG_PRINT("ib_log", ("write " LSN_PF, lsn));
 
-  log_sys.log.write(0, {buf, OS_FILE_LOG_BLOCK_SIZE});
-  if (!log_sys.log.writes_are_durable())
-    log_sys.log.flush();
+  log_sys.log.main_write_durable(0, {buf, OS_FILE_LOG_BLOCK_SIZE});
 }
 
-void log_t::file::read(os_offset_t offset, span<byte> buf)
+void log_t::file::main_read(os_offset_t offset, span<byte> buf)
 {
   if (const dberr_t err= fd.read(offset, buf))
-    ib::fatal() << "read(" << fd.get_path() << ") returned "<< err;
-}
-
-bool log_t::file::writes_are_durable() const noexcept
-{
-  return fd.writes_are_durable();
+    ib::fatal() << "read(" << fd.get_path() << ") returned " << err;
 }
 
-void log_t::file::write(os_offset_t offset, span<byte> buf)
+void log_t::file::main_write_durable(os_offset_t offset, span<byte> buf)
 {
   srv_stats.os_log_pending_writes.inc();
   if (const dberr_t err= fd.write(offset, buf))
@@ -499,25 +505,54 @@ void log_t::file::write(os_offset_t offset, span<byte> buf)
   srv_stats.os_log_written.add(buf.size());
   srv_stats.log_writes.inc();
   log_sys.n_log_ios++;
-}
 
-void log_t::file::flush()
-{
-  log_sys.pending_flushes.fetch_add(1, std::memory_order_acquire);
-  if (const dberr_t err= fd.flush())
-    ib::fatal() << "flush(" << fd.get_path() << ") returned " << err;
-  log_sys.pending_flushes.fetch_sub(1, std::memory_order_release);
-  log_sys.flushes.fetch_add(1, std::memory_order_release);
+  if (!fd.writes_are_durable())
+    if (const dberr_t err= fd.flush())
+      ib::fatal() << "flush(" << fd.get_path() << ") returned " << err;
 }
 
-void log_t::file::close_file()
+void log_t::file::close_files()
 {
   if (fd.is_opened())
-  {
     if (const dberr_t err= fd.close())
       ib::fatal() << "close(" << fd.get_path() << ") returned " << err;
-  }
-  fd.free();                                    // Free path
+  fd.free();
+
+  if (data_fd.is_opened())
+    if (const dberr_t err= data_fd.close())
+      ib::fatal() << "close(" << data_fd.get_path() << ") returned " << err;
+  data_fd.free();
+}
+
+void log_t::file::data_read(os_offset_t offset, span<byte> buf)
+{
+  if (const dberr_t err= data_fd.read(offset, buf))
+    ib::fatal() << "read(" << data_fd.get_path() << ") returned " << err;
+}
+
+bool log_t::file::data_writes_are_durable() const noexcept
+{
+  return data_fd.writes_are_durable();
+}
+
+void log_t::file::data_write(os_offset_t offset, span<byte> buf)
+{
+  srv_stats.os_log_pending_writes.inc();
+  if (const dberr_t err= data_fd.write(offset, buf))
+    ib::fatal() << "write(" << data_fd.get_path() << ") returned " << err;
+  srv_stats.os_log_pending_writes.dec();
+  srv_stats.os_log_written.add(buf.size());
+  srv_stats.log_writes.inc();
+  log_sys.n_log_ios++;
+}
+
+void log_t::file::/*data_*/flush()
+{
+  log_sys.pending_flushes.fetch_add(1, std::memory_order_acquire);
+  if (const dberr_t err= data_fd.flush())
+    ib::fatal() << "flush(" << data_fd.get_path() << ") returned " << err;
+  log_sys.pending_flushes.fetch_sub(1, std::memory_order_release);
+  log_sys.flushes.fetch_add(1, std::memory_order_release);
 }
 
 /** Initialize the redo log. */
@@ -530,7 +565,7 @@ void log_t::file::create()
   subformat= 2;
   file_size= srv_log_file_size;
   lsn= LOG_START_LSN;
-  lsn_offset= LOG_FILE_HDR_SIZE;
+  lsn_offset= 0;
 }
 
 /******************************************************//**
@@ -611,7 +646,7 @@ loop:
 
 	ut_a((next_offset >> srv_page_size_shift) <= ULINT_MAX);
 
-	log_sys.log.write(static_cast<size_t>(next_offset), {buf, write_len});
+	log_sys.log.data_write(next_offset, {buf, write_len});
 
 	if (write_len < len) {
 		start_lsn += write_len;
@@ -621,11 +656,10 @@ loop:
 	}
 }
 
-/** Flush the recently written changes to the log file.
-and invoke mysql_mutex_lock(&log_sys.mutex). */
+/** Flush the recently written changes to the log file */
 static void log_write_flush_to_disk_low(lsn_t lsn)
 {
-  if (!log_sys.log.writes_are_durable())
+  if (!log_sys.log.data_writes_are_durable())
     log_sys.log.flush();
   ut_a(lsn >= log_sys.get_flushed_lsn());
   log_sys.set_flushed_lsn(lsn);
@@ -762,7 +796,7 @@ static void log_write(bool rotate_key)
 		start_offset - area_start);
 	srv_stats.log_padded.add(pad_size);
 	log_sys.write_lsn = write_lsn;
-	if (log_sys.log.writes_are_durable()) {
+	if (log_sys.log.data_writes_are_durable()) {
 		log_sys.set_flushed_lsn(write_lsn);
 		log_flush_notify(write_lsn);
 	}
@@ -906,11 +940,10 @@ ATTRIBUTE_COLD void log_write_checkpoint_info(lsn_t end_lsn)
 	/* Note: We alternate the physical place of the checkpoint info.
 	See the (next_checkpoint_no & 1) below. */
 
-	log_sys.log.write((log_sys.next_checkpoint_no & 1) ? LOG_CHECKPOINT_2
-							   : LOG_CHECKPOINT_1,
-			  {buf, OS_FILE_LOG_BLOCK_SIZE});
-
-	log_sys.log.flush();
+	log_sys.log.main_write_durable((log_sys.next_checkpoint_no & 1)
+					       ? LOG_CHECKPOINT_2
+					       : LOG_CHECKPOINT_1,
+				       {buf, OS_FILE_LOG_BLOCK_SIZE});
 
 	mysql_mutex_lock(&log_sys.mutex);
 
@@ -1333,3 +1366,46 @@ std::vector<std::string> get_existing_log_files_paths() {
 
   return result;
 }
+
+dberr_t create_data_file(os_offset_t size)
+{
+  ut_ad(size > LOG_MAIN_FILE_SIZE);
+
+  const auto path= get_log_file_path(LOG_DATA_FILE_NAME);
+  os_file_delete_if_exists(innodb_log_file_key, path.c_str(), nullptr);
+
+  bool ret;
+  pfs_os_file_t file=
+      os_file_create(innodb_log_file_key, path.c_str(),
+                     OS_FILE_CREATE | OS_FILE_ON_ERROR_NO_EXIT, OS_FILE_NORMAL,
+                     OS_LOG_FILE, srv_read_only_mode, &ret);
+
+  if (!ret)
+  {
+    ib::error() << "Cannot create " << path;
+    return DB_ERROR;
+  }
+
+  ib::info() << "Setting log file " << path << " size to " << size << " bytes";
+
+  ret= os_file_set_size(path.c_str(), file, size);
+  if (!ret)
+  {
+    os_file_close(file);
+    ib::error() << "Cannot set log file " << path << " size to " << size
+                << " bytes";
+    return DB_ERROR;
+  }
+
+  if (!os_file_flush(file))
+  {
+    os_file_close(file);
+    ib::error() << "Error while flushing " << path;
+    return DB_ERROR;
+  }
+
+  ret= os_file_close(file);
+  ut_a(ret);
+
+  return DB_SUCCESS;
+}
diff --git a/storage/innobase/log/log0recv.cc b/storage/innobase/log/log0recv.cc
index 7720c041ece..22df7fca821 100644
--- a/storage/innobase/log/log0recv.cc
+++ b/storage/innobase/log/log0recv.cc
@@ -27,6 +27,7 @@ Created 9/20/1997 Heikki Tuuri
 
 #include "univ.i"
 
+#include <array>
 #include <map>
 #include <string>
 #include <my_service_manager.h>
@@ -1053,8 +1054,87 @@ void recv_sys_t::open_log_files_if_needed()
   }
 }
 
+void recv_sys_t::set_block_to_copy(os_offset_t off)
+{
+  ut_ad(off > 0);
+  block_to_copy_when_upgrading_file_format= off;
+}
+
+dberr_t recv_sys_t::upgrade_file_format_to_10_6_if_needed()
+{
+  if (block_to_copy_when_upgrading_file_format == 0)
+    return DB_SUCCESS;
+
+  ut_ad(!log_sys.log.data_is_opened());
+
+  if (dberr_t err= create_data_file(srv_log_file_size))
+    return err;
+
+  // Copy one block from old file to new file.
+  log_file_t data_fd(get_log_file_path(LOG_DATA_FILE_NAME));
+
+  if (dberr_t err= data_fd.open(false))
+    return err;
+
+  std::array<byte, OS_FILE_LOG_BLOCK_SIZE> buf alignas(OS_FILE_LOG_BLOCK_SIZE);
+  read(block_to_copy_when_upgrading_file_format, buf);
+  if (dberr_t err= data_fd.write(
+          block_to_copy_when_upgrading_file_format - LOG_MAIN_FILE_SIZE, buf))
+  {
+    return err;
+  }
+
+  if (!data_fd.writes_are_durable())
+    if (dberr_t err= data_fd.flush())
+      return err;
+
+  if (dberr_t err= data_fd.close())
+    return err;
+
+  // Set LOG_FILE_NAME size to LOG_MAIN_FILE_SIZE
+  bool ret;
+  std::string logfile0_path= recv_sys.files.front().get_path();
+  pfs_os_file_t logfile0=
+      os_file_create(innodb_log_file_key, logfile0_path.c_str(),
+                     OS_FILE_OPEN | OS_FILE_ON_ERROR_NO_EXIT, OS_FILE_NORMAL,
+                     OS_LOG_FILE, true, &ret);
+
+  if (!ret)
+  {
+    ib::error() << "Cannot create " << logfile0_path;
+    return DB_ERROR;
+  }
+
+  ret= os_file_set_size(logfile0_path.c_str(), logfile0, LOG_MAIN_FILE_SIZE);
+  if (!ret)
+  {
+    os_file_close(logfile0);
+    ib::error() << "Cannot set log file " << logfile0_path << " size to "
+                << LOG_MAIN_FILE_SIZE << " bytes";
+    return DB_ERROR;
+  }
+
+  ret= os_file_close(logfile0);
+  ut_a(ret);
+
+  // Remove now unneeded multiple leftover log files
+  const size_t files_found= files.size();
+  files.clear();
+  for (size_t i= 1; i < files_found; i++)
+    delete_log_file(std::to_string(i).c_str());
+
+  block_to_copy_when_upgrading_file_format= 0;
+  return DB_SUCCESS;
+}
+
 void recv_sys_t::read(os_offset_t total_offset, span<byte> buf)
 {
+  if (log_sys.log.data_is_opened())
+  {
+    log_sys.log.data_read(total_offset, buf);
+    return;
+  }
+
   open_log_files_if_needed();
 
   size_t file_idx= static_cast<size_t>(total_offset / log_sys.log.file_size);
@@ -1416,7 +1496,9 @@ bool log_t::file::read_log_seg(lsn_t* start_lsn, lsn_t end_lsn)
 	ut_ad(!(end_lsn % OS_FILE_LOG_BLOCK_SIZE));
 	byte* buf = log_sys.buf;
 loop:
-	lsn_t source_offset = calc_lsn_offset_old(*start_lsn);
+	lsn_t source_offset = log_sys.log.data_is_opened()
+				? calc_lsn_offset(*start_lsn)
+				: calc_lsn_offset_old(*start_lsn);
 
 	ut_a(end_lsn - *start_lsn <= ULINT_MAX);
 	len = (ulint) (end_lsn - *start_lsn);
@@ -1622,7 +1704,7 @@ ATTRIBUTE_COLD static dberr_t recv_log_recover_pre_10_2()
   for (ulint field= LOG_CHECKPOINT_1; field <= LOG_CHECKPOINT_2;
        field += LOG_CHECKPOINT_2 - LOG_CHECKPOINT_1)
   {
-    log_sys.log.read(field, {buf, OS_FILE_LOG_BLOCK_SIZE});
+    log_sys.log.main_read(field, {buf, OS_FILE_LOG_BLOCK_SIZE});
 
     if (static_cast<uint32_t>(ut_fold_binary(buf, CHECKSUM_1)) !=
         mach_read_from_4(buf + CHECKSUM_1) ||
@@ -1710,14 +1792,14 @@ in an old redo log file (during upgrade check).
 @return byte offset within the log */
 inline lsn_t log_t::file::calc_lsn_offset_old(lsn_t lsn) const
 {
-  const lsn_t size= capacity() * recv_sys.files_size();
+  constexpr size_t LOG_FILE_HDR_SIZE= 2048;
+  const lsn_t size= (file_size - LOG_FILE_HDR_SIZE) * recv_sys.files_size();
   lsn_t l= lsn - this->lsn;
   if (longlong(l) < 0)
   {
     l= lsn_t(-longlong(l)) % size;
     l= size - l;
   }
-
   l+= lsn_offset - LOG_FILE_HDR_SIZE * (1 + lsn_offset / file_size);
   l%= size;
   return l + LOG_FILE_HDR_SIZE * (1 + l / (file_size - LOG_FILE_HDR_SIZE));
@@ -1738,8 +1820,8 @@ static dberr_t recv_log_recover_10_4()
 		return DB_CORRUPTION;
 	}
 
-	recv_sys.read(source_offset & ~(OS_FILE_LOG_BLOCK_SIZE - 1),
-		      {buf, OS_FILE_LOG_BLOCK_SIZE});
+	log_sys.log.main_read(source_offset & ~(OS_FILE_LOG_BLOCK_SIZE - 1),
+			      {buf, OS_FILE_LOG_BLOCK_SIZE});
 
 	ulint crc = log_block_calc_checksum_crc32(buf);
 	ulint cksum = log_block_get_checksum(buf);
@@ -1797,7 +1879,7 @@ recv_find_max_checkpoint(ulint* max_field)
 
 	buf = log_sys.checkpoint_buf;
 
-	log_sys.log.read(0, {buf, OS_FILE_LOG_BLOCK_SIZE});
+	log_sys.log.main_read(0, {buf, OS_FILE_LOG_BLOCK_SIZE});
 	/* Check the header page checksum. There was no
 	checksum in the first redo log format (version 0). */
 	log_sys.log.format = mach_read_from_4(buf + LOG_HEADER_FORMAT);
@@ -1836,7 +1918,7 @@ recv_find_max_checkpoint(ulint* max_field)
 
 	for (field = LOG_CHECKPOINT_1; field <= LOG_CHECKPOINT_2;
 	     field += LOG_CHECKPOINT_2 - LOG_CHECKPOINT_1) {
-		log_sys.log.read(field, {buf, OS_FILE_LOG_BLOCK_SIZE});
+		log_sys.log.main_read(field, {buf, OS_FILE_LOG_BLOCK_SIZE});
 
 		const ulint crc32 = log_block_calc_checksum_crc32(buf);
 		const ulint cksum = log_block_get_checksum(buf);
@@ -3925,7 +4007,7 @@ err_exit:
 	}
 
 	buf = log_sys.checkpoint_buf;
-	log_sys.log.read(max_cp_field, {buf, OS_FILE_LOG_BLOCK_SIZE});
+	log_sys.log.main_read(max_cp_field, {buf, OS_FILE_LOG_BLOCK_SIZE});
 
 	checkpoint_lsn = mach_read_from_8(buf + LOG_CHECKPOINT_LSN);
 	checkpoint_no = mach_read_from_8(buf + LOG_CHECKPOINT_NO);
diff --git a/storage/innobase/srv/srv0start.cc b/storage/innobase/srv/srv0start.cc
index 9a1a8f4969e..85d9805b628 100644
--- a/storage/innobase/srv/srv0start.cc
+++ b/storage/innobase/srv/srv0start.cc
@@ -268,14 +268,11 @@ static dberr_t create_log_file(bool create_new_db, lsn_t lsn,
 		return DB_ERROR;
 	}
 
-	ib::info() << "Setting log file " << logfile0 << " size to "
-		   << srv_log_file_size << " bytes";
-
-	ret = os_file_set_size(logfile0.c_str(), file, srv_log_file_size);
+	ret = os_file_set_size(logfile0.c_str(), file, LOG_MAIN_FILE_SIZE);
 	if (!ret) {
 		os_file_close(file);
 		ib::error() << "Cannot set log file " << logfile0
-			    << " size to " << srv_log_file_size << " bytes";
+			    << " size to " << LOG_MAIN_FILE_SIZE << " bytes";
 		return DB_ERROR;
 	}
 
@@ -285,16 +282,20 @@ static dberr_t create_log_file(bool create_new_db, lsn_t lsn,
 	DBUG_EXECUTE_IF("innodb_log_abort_8", return(DB_ERROR););
 	DBUG_PRINT("ib_log", ("After innodb_log_abort_8"));
 
+	if (dberr_t err = create_data_file(srv_log_file_size)) {
+		return err;
+	}
+
 	/* We did not create the first log file initially as LOG_FILE_NAME, so
 	that crash recovery cannot find it until it has been completed and
-        renamed. */
+	renamed. */
 
 	log_sys.log.create();
 	if (!log_set_capacity(srv_log_file_size_requested)) {
 		return DB_ERROR;
 	}
 
-	log_sys.log.open_file(logfile0);
+	log_sys.log.open_files(logfile0);
 	if (!fil_system.sys_space->open(create_new_db)) {
 		return DB_ERROR;
 	}
@@ -308,7 +309,7 @@ static dberr_t create_log_file(bool create_new_db, lsn_t lsn,
 	lsn = ut_uint64_align_up(lsn, OS_FILE_LOG_BLOCK_SIZE);
 	log_sys.set_lsn(lsn + LOG_BLOCK_HDR_SIZE);
 	log_sys.log.set_lsn(lsn);
-	log_sys.log.set_lsn_offset(LOG_FILE_HDR_SIZE);
+	log_sys.log.set_lsn_offset(0);
 
 	log_sys.buf_next_to_write = 0;
 	log_sys.write_lsn = lsn;
@@ -1017,18 +1018,7 @@ static dberr_t find_and_check_log_file(bool &log_file_found)
     mariabackup --prepare. */
     return DB_NOT_FOUND;
   }
-  /* The first log file must consist of at least the following 512-byte pages:
-  header, checkpoint page 1, empty, checkpoint page 2, redo log page(s).
 
-  Mariabackup --prepare would create an empty LOG_FILE_NAME. Tolerate it. */
-  if (size == 0)
-    srv_start_after_restore= true;
-  else if (size <= OS_FILE_LOG_BLOCK_SIZE * 4)
-  {
-    ib::error() << "Log file " << logfile0 << " size " << size
-                << " is too small";
-    return DB_ERROR;
-  }
   srv_log_file_size= size;
 
   log_file_found= true;
@@ -1339,7 +1329,7 @@ dberr_t srv_start(bool create_new_db)
 
 		srv_log_file_found = log_file_found;
 
-		log_sys.log.open_file(get_log_file_path());
+		log_sys.log.open_files(get_log_file_path());
 
 		log_sys.log.create();
 
@@ -1442,6 +1432,10 @@ file_checked:
 
 		recv_sys.dblwr.pages.clear();
 
+		if (err == DB_SUCCESS && !create_new_log) {
+			err = recv_sys.upgrade_file_format_to_10_6_if_needed();
+		}
+
 		if (err != DB_SUCCESS) {
 			return(srv_init_abort(err));
 		}
@@ -1593,7 +1587,7 @@ file_checked:
 			ut_ad(recv_no_log_write);
 			err = fil_write_flushed_lsn(log_sys.get_lsn());
 			DBUG_ASSERT(!buf_pool.any_io_pending());
-			log_sys.log.close_file();
+			log_sys.log.close_files();
 			if (err == DB_SUCCESS) {
 				bool trunc = srv_operation
 					== SRV_OPERATION_RESTORE;
@@ -1652,8 +1646,9 @@ file_checked:
 				return(srv_init_abort(err));
 			}
 
-			/* Close the redo log file, so that we can replace it */
-			log_sys.log.close_file();
+			/* Close the redo log files, so that we can
+			replace it */
+			log_sys.log.close_files();
 
 			DBUG_EXECUTE_IF("innodb_log_abort_5",
 					return(srv_init_abort(DB_ERROR)););