Bug#11763573 - 56299: MUTEX DEADLOCK WITH COM_BINLOG_DUMP, BINLOG PURGE, AND PROCESSLIST/KILL

The bug case is similar to one fixed earlier bug_49536.
Deadlock involving LOCK_log appears to be possible because the purge running thread
is holding LOCK_log whereas there is no sense of doing that and which fact was
exploited by the earlier bug fixes.

Fixed with small reengineering of rotate_and_purge(), adding two new methods and
setting up a policy to execute those instead of the former
rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED).
The policy for using rotate(), purge() is that if the caller acquires LOCK_log itself,
it should call rotate(), release the mutex and run purge().

Side effect of this patch is refining error message of bug@11747416 to print
the whole path.



mysql-test/suite/rpl/r/rpl_cant_read_event_incident.result:
  the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_log_pos.result:
  the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_manual_change_index_file.result:
  the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_packet.result:
  the file name printing is changed to a relative path instead of just the file name.
mysql-test/suite/rpl/r/rpl_rotate_purge_deadlock.result:
  new result file is added.
mysql-test/suite/rpl/t/rpl_cant_read_event_incident.test:
  The test of that bug can't satisfy windows and unix backslash interpretation so windows
  execution is chosen to bypass.
mysql-test/suite/rpl/t/rpl_rotate_purge_deadlock-master.opt:
  new opt file is added.
mysql-test/suite/rpl/t/rpl_rotate_purge_deadlock.test:
  regression test is added as well as verification of a 
  possible side effect of the fixes is tried.
sql/log.cc:
  LOCK_log is never taken during execution of log purging routine.
  The former MYSQL_BIN_LOG::rotate_and_purge is made to necessarily 
  acquiring and releasing LOCK_log. 
  If caller takes the mutex itself it has to use a new rotate(), purge() 
  methods combination and to never let purge() be run with LOCK_log grabbed.
  
  
  
  split apart to allow
  the caller to chose either it
  Simulation of concurrently rotating/purging threads is added.
sql/log.h:
  new rotate(), purge() methods are added to be used instead of
  the former rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED).
  rotate_and_purge() signature is changed. Caller should not call rotate_and_purge()
  but rather {rotate(), purge()} if LOCK_log is acquired by it.
sql/rpl_injector.cc:
  changes to reflect the new rotate_and_purge() signature.
sql/sql_class.h:
  unnecessary constants are removed.
sql/sql_parse.cc:
  changes to reflect the new rotate_and_purge() signature.
sql/sql_reload.cc:
  changes to reflect the new rotate_and_purge() signature.
sql/sql_repl.cc:
  followup for bug@11747416: the file name printing is changed to a relative 
  path instead of just the file name.

mysql-test/suite/rpl/r/rpl_packet.result

@@ -37,7 +37,7 @@ DROP TABLE t1;
 CREATE TABLE t1 (f1 int PRIMARY KEY, f2 LONGTEXT, f3 LONGTEXT) ENGINE=MyISAM;
 INSERT INTO t1(f1, f2, f3) VALUES(1, REPEAT('a', @@global.max_allowed_packet), REPEAT('b', @@global.max_allowed_packet));
 include/wait_for_slave_io_error.inc [errno=1236]
-Last_IO_Error = 'Got fatal error 1236 from master when reading data from binary log: 'log event entry exceeded max_allowed_packet; Increase max_allowed_packet on master; the last event was read from 'master-bin.000001' at 463, the last byte read was read from 'master-bin.000001' at 482.''
+Last_IO_Error = 'Got fatal error 1236 from master when reading data from binary log: 'log event entry exceeded max_allowed_packet; Increase max_allowed_packet on master; the last event was read from './master-bin.000001' at 463, the last byte read was read from './master-bin.000001' at 482.''
 STOP SLAVE;
 RESET SLAVE;
 RESET MASTER;