Fix for BUG#791:

a safer way of initing the mutexes in MYSQL_LOG.
is_open() is now always thread-safe.
See each file for details.


sql/handler.cc:
  is_open() with locks
sql/item_func.cc:
  is_open() with locks
sql/log.cc:
  No more 'inited'.
  We now always use is_open() in a thread-safe manner.
  This simplifies some functions (no more need to test is_open() twice).
sql/log_event.cc:
  is_open() with locks
sql/mysqld.cc:
  Init mutexes for the global MYSQL_LOG objects.
  We care about no_rotate, because we can't do it in open() anymore (because
  we don't have 'inited' anymore).
sql/repl_failsafe.cc:
  is_open() with locks
sql/slave.cc:
  init pthread objects (mutexes, conds) in the constructor of st_relay_log_info.
  Some better locking in rotate_relay_log().
sql/sql_base.cc:
  is_open() with locks
sql/sql_class.h:
  Before, we inited LOCK_log in MYSQL_LOG::open(), so in other places of the code
  when we were never 100% sure that it had been inited. For example, if the server
  was running without --log-bin, ::open() was not called so the mutex was not
  inited. We could detect it with !inited, but not safely as 'inited' was not
  protected by any mutex.
  So now:
  we *always* init the LOCK_log mutex, even if the log is not used. We can't init
  the mutex in MYSQL_LOG's constructor, because for global objects like
  mysql_bin_log, mysql_log etc, the constructor is called before MY_INIT(), but
  safe_mutex depends on MY_INIT(). So we have a new function MYSQL_LOG::init_pthread_objects
  which we call in main(), after MY_INIT().
  For the relay log, we call this function in the constructor of
  st_relay_log_info, which is called before any function tries to
  use the relay log (the relay log is always invoked as rli.relay_log).
  So now we should be safe in all cases and we don't need 'inited'.
sql/sql_db.cc:
  is_open() with locks
sql/sql_delete.cc:
  is_open() with locks
sql/sql_insert.cc:
  is_open() with locks
sql/sql_load.cc:
  is_open() with locks
sql/sql_parse.cc:
  is_open() with locks
sql/sql_rename.cc:
  is_open() with locks
sql/sql_repl.cc:
  is_open() with locks
sql/sql_table.cc:
  is_open() with locks
sql/sql_update.cc:
  is_open() with locks

1 files changed, 4 insertions, 4 deletions

diff --git a/sql/sql_load.cc b/sql/sql_load.cc
index ee573672c35..7a20fbfd928 100644
--- a/sql/sql_load.cc
+++ b/sql/sql_load.cc
@@ -219,7 +219,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
     DBUG_RETURN(-1);				// Can't allocate buffers
   }
 
-  if (!opt_old_rpl_compat && mysql_bin_log.is_open())
+  if (!opt_old_rpl_compat && mysql_bin_log.is_open(1))
   {
     lf_info.thd = thd;
     lf_info.ex = ex;
@@ -281,7 +281,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   {
     if (transactional_table)
       ha_autocommit_or_rollback(thd,error);
-    if (!opt_old_rpl_compat && mysql_bin_log.is_open())
+    if (!opt_old_rpl_compat && mysql_bin_log.is_open(1))
     {
       if (lf_info.wrote_create_file)
       {
@@ -315,7 +315,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
 
   if (!log_delayed)
     thd->options|=OPTION_STATUS_NO_TRANS_UPDATE;
-  if (mysql_bin_log.is_open())
+  if (mysql_bin_log.is_open(1))
   {
     if (opt_old_rpl_compat)
     {
@@ -607,7 +607,7 @@ READ_INFO::READ_INFO(File file_par, uint tot_length, String &field_term,
 	cache.read_function = _my_b_net_read;
 
       need_end_io_cache = 1;
-      if (!opt_old_rpl_compat && mysql_bin_log.is_open())
+      if (!opt_old_rpl_compat && mysql_bin_log.is_open(1))
 	cache.pre_read = cache.pre_close =
 	  (IO_CACHE_CALLBACK) log_loaded_block;
     }