bk commit into 5.1 tree (ramil:1.2526) BUG#26380

[ramil]

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5.1 repository of ram. When ram does a push these changes will
be propagated to the main repository and, within 24 hours after the
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ChangeSet@stripped, 2007-05-31 12:48:10+05:00, ramil@stripped +3 -0
  Fix for bug #26380: LOCK TABLES + FLUSH LOGS causes deadlock
  
  Problem: executing 'flush logs' we don't check global read lock for a thread 
  launching the command. That may cause a deadlock if tables are locked
  and logger calls wait_if_global_read_lock() for the logging thread
  that is not the owner of the global read lock.
  
  Fix: check for global read lock before flushing logs.

  mysql-test/r/flush.result@stripped, 2007-05-31 12:48:08+05:00, ramil@stripped +17 -0
    Fix for bug #26380: LOCK TABLES + FLUSH LOGS causes deadlock
      - test result.

  mysql-test/t/flush.test@stripped, 2007-05-31 12:48:09+05:00, ramil@stripped +34 -1
    Fix for bug #26380: LOCK TABLES + FLUSH LOGS causes deadlock
      - test case.

  sql/sql_parse.cc@stripped, 2007-05-31 12:48:09+05:00, ramil@stripped +5 -0
    Fix for bug #26380: LOCK TABLES + FLUSH LOGS causes deadlock
      - check for global read lock before flushing logs.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	ramil
# Host:	ramil.myoffice.izhnet.ru
# Root:	/home/ram/work/b26380/b26380.5.1

--- 1.670/sql/sql_parse.cc	2007-05-31 12:48:15 +05:00
+++ 1.671/sql/sql_parse.cc	2007-05-31 12:48:16 +05:00
@@ -6220,6 +6220,9 @@ bool reload_acl_and_cache(THD *thd, ulon
       tables.
     */
 
+    if (wait_if_global_read_lock(thd, 0, 1))
+      return 1;
+    
     /*
       Writing this command to the binlog may result in infinite loops
       when doing mysqlbinlog|mysql, and anyway it does not really make
@@ -6244,6 +6247,8 @@ bool reload_acl_and_cache(THD *thd, ulon
       result=1;
     if (flush_error_log())
       result=1;
+
+    start_waiting_global_read_lock(thd);
   }
 #ifdef HAVE_QUERY_CACHE
   if (options & REFRESH_QUERY_CACHE_FREE)

--- 1.16/mysql-test/r/flush.result	2007-05-31 12:48:16 +05:00
+++ 1.17/mysql-test/r/flush.result	2007-05-31 12:48:16 +05:00
@@ -55,3 +55,20 @@ flush tables with read lock;
 insert into t2 values(1);
 unlock tables;
 drop table t1, t2;
+End of 5.0 tests
+select @@global.general_log;
+@@global.general_log
+1
+flush tables with read lock;
+flush logs;
+ERROR HY000: Can't execute the query because you have a conflicting read lock
+unlock tables;
+flush tables with read lock;
+flush logs;
+flush logs;
+ERROR HY000: Can't execute the query because you have a conflicting read lock
+unlock tables;
+select @@global.general_log;
+@@global.general_log
+1
+End of 5.1 tests

--- 1.23/mysql-test/t/flush.test	2007-05-31 12:48:16 +05:00
+++ 1.24/mysql-test/t/flush.test	2007-05-31 12:48:16 +05:00
@@ -133,4 +133,37 @@ disconnect con3;
 connection default;
 drop table t1, t2;
 
-# End of 5.0 tests
+--echo End of 5.0 tests
+
+#
+# Bug #26380: LOCK TABLES + FLUSH LOGS causes deadlock
+#
+select @@global.general_log;
+flush tables with read lock;
+--error 1223
+flush logs;
+unlock tables;
+
+connect (con1,localhost,root,,);
+connect (con2,localhost,root,,);
+
+connection con1;
+flush tables with read lock;
+
+connection con2;
+send flush logs;
+
+connection con1;
+--error 1223
+flush logs;
+unlock tables;
+disconnect con1;
+
+connection con2;
+reap;
+select @@global.general_log;
+disconnect con2;
+
+connection default;
+
+--echo End of 5.1 tests