From d2d605e4ea578cf49adb52ebd834363962d099d8 Mon Sep 17 00:00:00 2001
From: unknown <jonas@perch.ndb.mysql.com>
Date: Mon, 4 Sep 2006 13:43:34 +0200
Subject: [PATCH] bug#21965 - replication   fix deadlock if master switches log
 file in parallell with "show master logs"

sql/log.cc:
  add raw_get_current_log which dont take log mutex
sql/sql_class.h:
  add raw_get_current_log which dont take log mutex
sql/sql_repl.cc:
  Fix lock order i.e first log_lock then index_lock
---
 sql/log.cc      | 11 ++++++++---
 sql/sql_class.h |  1 +
 sql/sql_repl.cc |  8 ++++++--
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/sql/log.cc b/sql/log.cc
index c530f15a84f..5ae89dfeb50 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -409,12 +409,17 @@ shutdown the MySQL server and restart it.", log_name, errno);
 int MYSQL_LOG::get_current_log(LOG_INFO* linfo)
 {
   pthread_mutex_lock(&LOCK_log);
-  strmake(linfo->log_file_name, log_file_name, sizeof(linfo->log_file_name)-1);
-  linfo->pos = my_b_tell(&log_file);
+  int ret = raw_get_current_log(linfo);
   pthread_mutex_unlock(&LOCK_log);
-  return 0;
+  return ret;
 }
 
+int MYSQL_LOG::raw_get_current_log(LOG_INFO* linfo)
+{
+  strmake(linfo->log_file_name, log_file_name, sizeof(linfo->log_file_name)-1);
+  linfo->pos = my_b_tell(&log_file);
+  return 0;
+}
 
 /*
   Move all data up in a file in an filename index file
diff --git a/sql/sql_class.h b/sql/sql_class.h
index e8fe175cd7c..a995a492bc8 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -177,6 +177,7 @@ public:
 		   bool need_mutex);
   int find_next_log(LOG_INFO* linfo, bool need_mutex);
   int get_current_log(LOG_INFO* linfo);
+  int raw_get_current_log(LOG_INFO* linfo);
   uint next_file_id();
   inline bool is_open() { return log_type != LOG_CLOSED; }
   inline char* get_index_fname() { return index_file_name;}
diff --git a/sql/sql_repl.cc b/sql/sql_repl.cc
index 963c4ccf5a6..2a7ab55b8c4 100644
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@@ -1359,10 +1359,14 @@ int show_binlogs(THD* thd)
                                            MYSQL_TYPE_LONGLONG));
   if (protocol->send_fields(&field_list, 1))
     DBUG_RETURN(1);
+  
+  pthread_mutex_lock(mysql_bin_log.get_log_lock());
   mysql_bin_log.lock_index();
   index_file=mysql_bin_log.get_index_file();
-
-  mysql_bin_log.get_current_log(&cur);
+  
+  mysql_bin_log.raw_get_current_log(&cur); // dont take mutex
+  pthread_mutex_unlock(mysql_bin_log.get_log_lock()); // lockdep, OK
+  
   cur_dir_len= dirname_length(cur.log_file_name);
 
   reinit_io_cache(index_file, READ_CACHE, (my_off_t) 0, 0, 0);