PS-269 (Initial Percona Server 8.0.12 tree) - encryption

A subset of binlog encryption tests was crashing with:

* thread percona#39, stop reason = signal SIGSTOP
    frame #0: 0x00007fff56063b66 libsystem_kernel.dylib`__pthread_kill + 10
    frame #1: 0x00007fff5622e080 libsystem_pthread.dylib`pthread_kill + 333
    frame #2: 0x000000010657442b mysqld-debug`my_write_core(sig=11) at stacktrace.cc:278
    frame #3: 0x0000000104d84334 mysqld-debug`::handle_fatal_signal(sig=11) at signal_handler.cc:254
    frame #4: 0x00007fff56221f5a libsystem_platform.dylib`_sigtramp + 26
    frame #5: 0x00007fff5622934d libsystem_pthread.dylib`pthread_mutex_lock + 1
    frame #6: 0x0000000106578d05 mysqld-debug`native_mutex_lock(mutex=0x0000000000000000) at thr_mutex.h:93
    frame #7: 0x0000000106578a57 mysqld-debug`safe_mutex_lock(mp=0x0000000000000000, try_lock=false, file="/Users/laurynas/percona/mysql-server/mysys/mf_iocache2.cc", line=113) at thr_mutex.cc:70
    frame #8: 0x000000010653cd3a mysqld-debug`my_mutex_lock(mp=0x00007ffb6b215038, file="/Users/laurynas/percona/mysql-server/mysys/mf_iocache2.cc", line=113) at thr_mutex.h:180
    frame #9: 0x000000010653b2cc mysqld-debug`inline_mysql_mutex_lock(that=0x00007ffb6b215038, src_file="/Users/laurynas/percona/mysql-server/mysys/mf_iocache2.cc", src_line=113) at mysql_mutex.h:267
  * frame #10: 0x000000010653b0d8 mysqld-debug`my_b_append_tell(info=0x00007ffb6b214fd8) at mf_iocache2.cc:113
    frame #11: 0x0000000105ed6a96 mysqld-debug`MYSQL_BIN_LOG::write_buffer(this=0x00007ffb6b214cb8, buf="", len=47, mi=0x00007ffb6b1f6a00) at binlog.cc:7128
    frame #12: 0x0000000105f4d54b mysqld-debug`queue_event(mi=0x00007ffb6b1f6a00, buf="", event_len=47, do_flush_mi=true) at rpl_slave.cc:7756
    frame percona#13: 0x0000000105f3a243 mysqld-debug`::handle_slave_io(arg=0x00007ffb6b1f6a00) at rpl_slave.cc:5382
    frame percona#14: 0x00000001065b87a5 mysqld-debug`pfs_spawn_thread(arg=0x00007ffb6a543af0) at pfs.cc:2836
    frame percona#15: 0x00007fff5622b661 libsystem_pthread.dylib`_pthread_body + 340
    frame percona#16: 0x00007fff5622b50d libsystem_pthread.dylib`_pthread_start + 377
    frame percona#17: 0x00007fff5622abf9 libsystem_pthread.dylib`thread_start + 13

This was caused by my_b_append_tell trying to lock a nullptr
IO_CACHE::append_buffer_lock. The lock was nullptr, because it's only
initialized for SEQ_READ_APPEND IO_CACHEs, whereas we have
WRITE_CACHE. This mismatch was introduced by WL#8599 [1] changing the
IO_CACHE type from the former to the latter.

Fix by using the correct API for the new IO_CACHE type: my_b_tell
instead of my_b_append_tell.

[1]:

commit dbd2ca2
Author: Joao Gramacho <joao.gramacho@oracle.com>
Date:   Tue Nov 1 06:45:39 2016 +0000

    WL#8599: Reduce contention in IO and SQL threads
    (...)

mysql-test/suite/binlog_encryption/my.cnf

@@ -6,7 +6,7 @@
 [mysqld.1]
 encrypt-binlog=1
 master-verify-checksum=1
-log-bin=master-bin
+log-bin=binlog
 plugin_dir=@env.KEYRING_PLUGIN_DIR
 early-plugin-load=@env.KEYRING_PLUGIN
 keyring_file_data=../../tmp/keyring1

mysql-test/suite/binlog_encryption/r/binlog_incident.result

@@ -19,9 +19,9 @@ CREATE TABLE t1(c1 INT PRIMARY KEY, data TEXT(30000)) ENGINE=MyIsam;
 Got one of the listed errors
 include/show_binlog_events.inc
 Log_name	Pos	Event_type	Server_id	End_log_pos	Info
-master-bin.000001	#	Query	#	#	use `test`; CREATE TABLE t1(c1 INT PRIMARY KEY, data TEXT(30000)) ENGINE=MyIsam
-master-bin.000001	#	Incident	#	#	#1 (LOST_EVENTS)
-master-bin.000001	#	Rotate	#	#	master-bin.000002;pos=POS
+binlog.000001	#	Query	#	#	use `test`; CREATE TABLE t1(c1 INT PRIMARY KEY, data TEXT(30000)) ENGINE=MyIsam
+binlog.000001	#	Incident	#	#	#1 (LOST_EVENTS)
+binlog.000001	#	Rotate	#	#	binlog.000002;pos=POS
 DROP TABLE t1;
 Contain RELOAD DATABASE
 1