Fixed warnings and errors found by buildbot

field.cc
- Fixed warning about overlapping memory copy (backport from 10.0)

Item_subselect.cc
- Fixed core dump in main.view
- Problem was that thd->lex->current_select->master_unit()->item was not set, which caused crash in maxr_as_dependent

sql/mysqld.cc
- Got error on shutdown as we where freeing mutex before all THD objects was freed
  (~THD uses some mutex). Fixed by during shutdown freeing THD inside mutex.

sql/log.cc
- log_space_lock and LOCK_log where locked in inconsistenly. Fixed by not having a log_space_lock around purge_logs.

sql/slave.cc
- Remove unnecessary log_space_lock
- Move cond_broadcast inside lock to ensure we don't miss the signal

Author: montywi

sql/field.cc

@@ -7612,7 +7612,8 @@ int Field_geom::store(const char *from, uint length, CHARSET_INFO *cs)
     }
 
     Field_blob::store_length(length);
-    if (table->copy_blobs || length <= MAX_FIELD_WIDTH)
+    if ((table->copy_blobs || length <= MAX_FIELD_WIDTH) &&
+        from != value.ptr())
     {						// Must make a copy
       value.copy(from, length, cs);
       from= value.ptr();

sql/item_subselect.cc

@@ -2018,10 +2018,21 @@ Item_in_subselect::create_single_in_to_exists_cond(JOIN *join,
   */
   if (expr && !expr->fixed)
   {
+    bool tmp;
     SELECT_LEX *save_current_select= thd->lex->current_select;
+    Item_subselect *save_item;
+
     thd->lex->current_select= thd->lex->current_select->outer_select();
-    bool tmp;
+    /*
+      For st_select_lex::mark_as_dependent, who needs to mark
+      this sub query as correlated.
+    */
+    save_item= thd->lex->current_select->master_unit()->item;
+    thd->lex->current_select->master_unit()->item= this;
+
     tmp= expr->fix_fields(thd, 0);
+
+    thd->lex->current_select->master_unit()->item= save_item;
     thd->lex->current_select= save_current_select;
     if (tmp)
       DBUG_RETURN(true);

sql/log.cc

@@ -3676,6 +3676,7 @@ int MYSQL_BIN_LOG::purge_first_log(Relay_log_info* rli, bool included)
 {
   int error;
   char *to_purge_if_included= NULL;
+  ulonglong log_space_reclaimed= 0;
   DBUG_ENTER("purge_first_log");
 
   DBUG_ASSERT(is_open());
@@ -3724,17 +3725,13 @@ int MYSQL_BIN_LOG::purge_first_log(Relay_log_info* rli, bool included)
 
   DBUG_EXECUTE_IF("crash_before_purge_logs", DBUG_SUICIDE(););
 
-  mysql_mutex_lock(&rli->log_space_lock);
   rli->relay_log.purge_logs(to_purge_if_included, included,
-                            0, 0, &rli->log_space_total);
-  mysql_mutex_unlock(&rli->log_space_lock);
+                            0, 0, &log_space_reclaimed);
 
-  /*
-    Ok to broadcast after the critical region as there is no risk of
-    the mutex being destroyed by this thread later - this helps save
-    context switches
-  */
+  mysql_mutex_lock(&rli->log_space_lock);
+  rli->log_space_total-= log_space_reclaimed;
   mysql_cond_broadcast(&rli->log_space_cond);
+  mysql_mutex_unlock(&rli->log_space_lock);
 
   /*
    * Need to update the log pos because purge logs has been called 
@@ -3783,8 +3780,8 @@ int MYSQL_BIN_LOG::update_log_index(LOG_INFO* log_info, bool need_update_threads
   @param need_mutex
   @param need_update_threads If we want to update the log coordinates of
                              all threads. False for relay logs, true otherwise.
-  @param freed_log_space     If not null, decrement this variable of
-                             the amount of log space freed
+  @param reclaimeed_log_space If not null, increment this variable to
+                              the amount of log space freed
 
   @note
     If any of the logs before the deleted one is in use,
@@ -3800,10 +3797,10 @@ int MYSQL_BIN_LOG::update_log_index(LOG_INFO* log_info, bool need_update_threads
 */
 
 int MYSQL_BIN_LOG::purge_logs(const char *to_log, 
-                          bool included,
-                          bool need_mutex, 
-                          bool need_update_threads, 
-                          ulonglong *decrease_log_space)
+                              bool included,
+                              bool need_mutex, 
+                              bool need_update_threads, 
+                              ulonglong *reclaimed_space)
 {
   int error= 0;
   bool exit_loop= 0;
@@ -3868,7 +3865,7 @@ int MYSQL_BIN_LOG::purge_logs(const char *to_log,
 err:
   /* Read each entry from purge_index_file and delete the file. */
   if (is_inited_purge_index_file() &&
-      (error= purge_index_entry(thd, decrease_log_space, FALSE)))
+      (error= purge_index_entry(thd, reclaimed_space, FALSE)))
     sql_print_error("MSYQL_BIN_LOG::purge_logs failed to process registered files"
                     " that would be purged.");
   close_purge_index_file();
@@ -3973,7 +3970,7 @@ int MYSQL_BIN_LOG::register_create_index_entry(const char *entry)
   DBUG_RETURN(register_purge_index_entry(entry));
 }
 
-int MYSQL_BIN_LOG::purge_index_entry(THD *thd, ulonglong *decrease_log_space,
+int MYSQL_BIN_LOG::purge_index_entry(THD *thd, ulonglong *reclaimed_space,
                                      bool need_mutex)
 {
   DBUG_ENTER("MYSQL_BIN_LOG:purge_index_entry");
@@ -4093,8 +4090,8 @@ int MYSQL_BIN_LOG::purge_index_entry(THD *thd, ulonglong *decrease_log_space,
         DBUG_PRINT("info",("purging %s",log_info.log_file_name));
         if (!my_delete(log_info.log_file_name, MYF(0)))
         {
-          if (decrease_log_space)
-            *decrease_log_space-= s.st_size;
+          if (reclaimed_space)
+            *reclaimed_space+= s.st_size;
         }
         else
         {

sql/mysqld.cc

@@ -2488,14 +2488,23 @@ void unlink_thd(THD *thd)
   thd->add_status_to_global();
 
   mysql_mutex_lock(&LOCK_thread_count);
-  thread_count--;
   thd->unlink();
   /*
     Used by binlog_reset_master.  It would be cleaner to use
     DEBUG_SYNC here, but that's not possible because the THD's debug
     sync feature has been shut down at this point.
   */
   DBUG_EXECUTE_IF("sleep_after_lock_thread_count_before_delete_thd", sleep(5););
+  if (unlikely(abort_loop))
+  {
+    /*
+      During shutdown, we have to delete thd inside the mutex
+      to not refer to mutexes that may be deleted during shutdown
+    */
+    delete thd;
+    thd= 0;
+  }
+  thread_count--;
   mysql_mutex_unlock(&LOCK_thread_count);
 
   delete thd;

sql/slave.cc

@@ -3556,9 +3556,7 @@ pthread_handler_t handle_slave_sql(void *arg)
   rli->clear_error();
 
   //tell the I/O thread to take relay_log_space_limit into account from now on
-  mysql_mutex_lock(&rli->log_space_lock);
   rli->ignore_log_space_limit= 0;
-  mysql_mutex_unlock(&rli->log_space_lock);
   rli->trans_retries= 0; // start from "no error"
   DBUG_PRINT("info", ("rli->trans_retries: %lu", rli->trans_retries));
 
@@ -5228,14 +5226,8 @@ static Log_event* next_event(Relay_log_info* rli)
           rli->ignore_log_space_limit= true;
         }
 
-        /*
-          If the I/O thread is blocked, unblock it.  Ok to broadcast
-          after unlock, because the mutex is only destroyed in
-          ~Relay_log_info(), i.e. when rli is destroyed, and rli will
-          not be destroyed before we exit the present function.
-        */
-        mysql_mutex_unlock(&rli->log_space_lock);
         mysql_cond_broadcast(&rli->log_space_cond);
+        mysql_mutex_unlock(&rli->log_space_lock);
         // Note that wait_for_update_relay_log unlocks lock_log !
         rli->relay_log.wait_for_update_relay_log(rli->sql_thd);
         // re-acquire data lock since we released it earlier