MDEV-13311 Presence of old logs in 10.2.7 will corrupt restored instance (change in behavior)

Mariabackup 10.2.7 would delete the redo log files after a successful
--prepare operation. If the user is manually copying the prepared files
instead of using the --copy-back option, it could happen that some old
redo log file would be preserved in the restored location. These old
redo log files could cause corruption of the restored data files when
the server is started up.

We prevent this scenario by creating a "poisoned" redo log file
ib_logfile0 at the end of the --prepare step. The poisoning consists
of simply truncating the file to an empty file. InnoDB will refuse
to start up on an empty redo log file.

copy_back(): Delete all redo log files in the target if the source
file ib_logfile0 is empty. (Previously we did this if the source
file is missing.)

SRV_OPERATION_RESTORE_EXPORT: A new variant of SRV_OPERATION_RESTORE
when the --export option is specified. In this mode, we will keep
deleting all redo log files, instead of truncating the first one.

delete_log_files(): Add a parameter for the first file to delete,
to be passed as 0 or 1.

innobase_start_or_create_for_mysql(): In mariabackup --prepare,
tolerate an empty ib_logfile0 file. Otherwise, require the first
redo log file to be longer than 4 blocks (2048 bytes). Unless
--export was specified, truncate the first log file at the
end of --prepare.

2 files changed, 29 insertions, 4 deletions

diff --git a/mysql-test/suite/innodb/r/log_file_size.result b/mysql-test/suite/innodb/r/log_file_size.result
index b576061e74b..e049b34ad81 100644
--- a/mysql-test/suite/innodb/r/log_file_size.result
+++ b/mysql-test/suite/innodb/r/log_file_size.result
@@ -1,4 +1,12 @@
 CREATE TABLE t1(a INT PRIMARY KEY) ENGINE=InnoDB;
+SELECT * FROM INFORMATION_SCHEMA.ENGINES
+WHERE engine = 'innodb'
+AND support IN ('YES', 'DEFAULT', 'ENABLED');
+ENGINE	SUPPORT	COMMENT	TRANSACTIONS	XA	SAVEPOINTS
+FOUND 1 /InnoDB: Log file .*ib_logfile0 size 0 is too small/ in mysqld.1.err
+CHECK TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
 BEGIN;
 INSERT INTO t1 VALUES (42);
 SELECT * FROM t1;
diff --git a/mysql-test/suite/innodb/t/log_file_size.test b/mysql-test/suite/innodb/t/log_file_size.test
index 206444115fc..140198de4ab 100644
--- a/mysql-test/suite/innodb/t/log_file_size.test
+++ b/mysql-test/suite/innodb/t/log_file_size.test
@@ -23,14 +23,33 @@ call mtr.add_suppression("InnoDB: Log file .*ib_logfile[01].* size");
 call mtr.add_suppression("InnoDB: Unable to open .*ib_logfile0. to check native AIO read support");
 FLUSH TABLES;
 --enable_query_log
+let MYSQLD_DATADIR= `select @@datadir`;
+CREATE TABLE t1(a INT PRIMARY KEY) ENGINE=InnoDB;
+
+--source include/shutdown_mysqld.inc
+--move_file $MYSQLD_DATADIR/ib_logfile0 $MYSQLD_DATADIR/ib_logfile.old
+write_file $MYSQLD_DATADIR/ib_logfile0;
+EOF
+let $check_no_innodb=SELECT * FROM INFORMATION_SCHEMA.ENGINES
+WHERE engine = 'innodb'
+AND support IN ('YES', 'DEFAULT', 'ENABLED');
 
 --let $restart_parameters= --innodb-thread-concurrency=1 --innodb-log-file-size=1m --innodb-log-files-in-group=2
---source include/restart_mysqld.inc
+--source include/start_mysqld.inc
+
+eval $check_no_innodb;
+--remove_file $MYSQLD_DATADIR/ib_logfile0
+--move_file $MYSQLD_DATADIR/ib_logfile.old $MYSQLD_DATADIR/ib_logfile.0
+--source include/shutdown_mysqld.inc
+let SEARCH_FILE= $MYSQLTEST_VARDIR/log/mysqld.1.err;
+let SEARCH_PATTERN= InnoDB: Log file .*ib_logfile0 size 0 is too small;
+--source include/search_pattern_in_file.inc
+--source include/start_mysqld.inc
+CHECK TABLE t1;
 
 --let $restart_parameters= --innodb-thread-concurrency=100 --innodb-log-file-size=10M --innodb-log-files-in-group=2
 --source include/restart_mysqld.inc
 
-CREATE TABLE t1(a INT PRIMARY KEY) ENGINE=InnoDB;
 BEGIN;
 INSERT INTO t1 VALUES (42);
 
@@ -52,9 +71,7 @@ SELECT * FROM t1;
 
 INSERT INTO t1 VALUES (0),(123);
 
-let MYSQLD_DATADIR= `select @@datadir`;
 let SEARCH_ABORT = NOT FOUND;
-let SEARCH_FILE= $MYSQLTEST_VARDIR/log/mysqld.1.err;
 
 BEGIN;
 DELETE FROM t1 WHERE a>0;