Maria: more log handler fixes for when logs manually deleted

mysql-test/include/maria_empty_logs.inc:
  can now ask that control file be preserved
mysql-test/lib/mtr_report.pl:
  expected warning (produced by translog_init() when log is missing)
mysql-test/r/maria-recovery.result:
  result update
mysql-test/t/maria-recovery.test:
  test of removing logs manually; recovery used to fail
storage/maria/ma_loghandler.c:
  The addition to maria-recovery.test uncovered a bug: log 1 was
  manually deleted, Maria restarted, created log 2, then crash
  before a checkpoint: logs_found is TRUE, last_checkpoint_lsn
  is LSN_IMPOSSIBLE, so sure_page assumes that log 1 exists;
  using last_logno instead (only the last log needs to be checked,
  as the 'else' branch checks only after last_checkpoint_lsn:
  creation of a log is as good a starting point as a checkpoint,
  for scanning the log).

mysql-test/include/maria_empty_logs.inc

 # Maria help script.
 # Cleans up all logs to give recovery a fresh start.
 
-# API: none, just uses vardir, port and socket.
+# API: set mel_keep_control_file=1 if want to keep control file;
+# uses vardir, port and socket.
 
 connection admin;
 
@@ -12,7 +13,10 @@ EOF
 
 --exec $MYSQLADMIN --no-defaults -S $MASTER_MYSOCK -P $MASTER_MYPORT  -u root --password= shutdown 2>&1;
 
-remove_file $MYSQLTEST_VARDIR/master-data/maria_log_control;
+if (!$mel_keep_control_file)
+{
+  remove_file $MYSQLTEST_VARDIR/master-data/maria_log_control;
+}
 remove_file $MYSQLTEST_VARDIR/master-data/maria_log.00000001;
 -- error 0,1 # maybe there is just one log
 remove_file $MYSQLTEST_VARDIR/master-data/maria_log.00000002;

mysql-test/lib/mtr_report.pl

@@ -363,7 +363,10 @@ sub mtr_report_stats ($) {
 		# master
 		/Slave: Unknown column 'c7' in 't15' Error_code: 1054/ or
 		/Slave: Can't DROP 'c7'.* 1091/ or
-		/Slave: Key column 'c6'.* 1072/
+		/Slave: Key column 'c6'.* 1072/ or
+
+                # maria-recovery.test has warning about missing log file
+                /Can't get stat of '.*maria_log.00*/
 	       )
             {
               next;                       # Skip these lines

mysql-test/r/maria-recovery.result

@@ -214,6 +214,28 @@ t1	CREATE TABLE `t1` (
   KEY `c` (`c`)
 ) ENGINE=MARIA AUTO_INCREMENT=16 DEFAULT CHARSET=latin1
 drop table t1;
+* TEST of removing logs manually
+* shut down mysqld, removed logs, restarted it
+use mysqltest;
+create table t1 (a varchar(1000)) engine=maria;
+insert into t1 values ("00000000");
+flush table t1;
+* copied t1 for comparison
+lock tables t1 write;
+insert into t1 values ("aaaaaaaaa");
+SET SESSION debug="+d,maria_flush_whole_log,maria_crash";
+* crashing mysqld intentionally
+set global maria_checkpoint_interval=1;
+ERROR HY000: Lost connection to MySQL server during query
+* recovery happens
+check table t1 extended;
+Table	Op	Msg_type	Msg_text
+mysqltest.t1	check	status	OK
+* testing that checksum after recovery is as expected
+Checksum-check
+ok
+use mysqltest;
+drop table t1;
 drop database mysqltest_for_feeding_recovery;
 drop database mysqltest_for_comparison;
 drop database mysqltest;

mysql-test/t/maria-recovery.test

@@ -179,6 +179,27 @@ let $mvr_crash_statement= set global maria_checkpoint_interval=1;
 show create table t1;
 drop table t1;
 
+# Test of removing logs manually
+--echo * TEST of removing logs manually
+let $mel_keep_control_file=1;
+# this will shut mysqld down cleanly (so, take a checkpoint) and
+# remove only logs; at restart Maria will create a new log with a high
+# number
+-- source include/maria_empty_logs.inc
+let $mel_keep_control_file=0;
+# and see if even a next recovery is ok
+let $mvr_restore_old_snapshot=0;
+let $mms_compare_physically=0;
+let $mvr_crash_statement= set global maria_checkpoint_interval=1;
+let $mvr_debug_option="+d,maria_flush_whole_log,maria_crash";
+create table t1 (a varchar(1000)) engine=maria;
+insert into t1 values ("00000000");
+-- source include/maria_make_snapshot_for_comparison.inc
+lock tables t1 write;
+insert into t1 values ("aaaaaaaaa");
+-- source include/maria_verify_recovery.inc
+drop table t1;
+
 # clean up everything
 let $mms_purpose=feeding_recovery;
 eval drop database mysqltest_for_$mms_purpose;

storage/maria/ma_loghandler.c

@@ -3205,8 +3205,8 @@ my_bool translog_init_with_table(const char *directory,
     if (LSN_FILE_NO(last_checkpoint_lsn) == FILENO_IMPOSSIBLE)
     {
       DBUG_ASSERT(LSN_OFFSET(last_checkpoint_lsn) == 0);
-      /* there was no checkpoints we will read from the beginning */
-      sure_page= (LSN_ONE_FILE | TRANSLOG_PAGE_SIZE);
+      /* only last log needs to be checked */
+      sure_page= MAKE_LSN(last_logno, TRANSLOG_PAGE_SIZE);
     }
     else
     {