diff --git a/mysql-test/r/temp_table.result b/mysql-test/r/temp_table.result
index 0b6bc48c350..80d4e8cc06d 100644
--- a/mysql-test/r/temp_table.result
+++ b/mysql-test/r/temp_table.result
@@ -108,3 +108,20 @@ d	c
 bar	2
 foo	1
 drop table t1, t2;
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (i INT);
+LOCK TABLE t1 WRITE;
+CREATE TEMPORARY TABLE t1 (i INT);
+The following command should not block
+DROP TEMPORARY TABLE t1;
+DROP TABLE t1;
+CREATE TABLE t1 (i INT);
+CREATE TEMPORARY TABLE t2 (i INT);
+DROP TEMPORARY TABLE t2, t1;
+ERROR 42S02: Unknown table 't1'
+SELECT * FROM t2;
+ERROR 42S02: Table 'test.t2' doesn't exist
+SELECT * FROM t1;
+i
+DROP TABLE t1;
+End of 4.1 tests.
diff --git a/mysql-test/t/temp_table.test b/mysql-test/t/temp_table.test
index 309855d0b2d..69082840988 100644
--- a/mysql-test/t/temp_table.test
+++ b/mysql-test/t/temp_table.test
@@ -99,4 +99,50 @@ insert into t2 values (NULL, 'foo'), (NULL, 'bar');
 select d, c from t1 left join t2 on b = c where a = 3 order by d;
 drop table t1, t2;
 
-# End of 4.1 tests
+
+#
+# BUG#21096: locking issue ; temporary table conflicts.
+#
+# The problem was that on DROP TEMPORARY table name lock was acquired,
+# which should not be done.
+#
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+CREATE TABLE t1 (i INT);
+
+LOCK TABLE t1 WRITE;
+
+connect (conn1, localhost, root,,);
+
+CREATE TEMPORARY TABLE t1 (i INT);
+
+--echo The following command should not block
+DROP TEMPORARY TABLE t1;
+
+disconnect conn1;
+connection default;
+
+DROP TABLE t1;
+
+#
+# Check that it's not possible to drop a base table with
+# DROP TEMPORARY statement.
+#
+CREATE TABLE t1 (i INT);
+CREATE TEMPORARY TABLE t2 (i INT);
+
+--error 1051
+DROP TEMPORARY TABLE t2, t1;
+
+# Table t2 should have been dropped.
+--error 1146
+SELECT * FROM t2;
+# But table t1 should still be there.
+SELECT * FROM t1;
+
+DROP TABLE t1;
+
+
+--echo End of 4.1 tests.
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 74a9fc573c4..33e923e1553 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -933,17 +933,28 @@ JOIN::optimize()
 
     tmp_table_param.hidden_field_count= (all_fields.elements -
 					 fields_list.elements);
+    ORDER *tmp_group= ((!simple_group && !procedure &&
+                        !(test_flags & TEST_NO_KEY_GROUP)) ? group_list :
+                                                             (ORDER*) 0);
+    /*
+      Pushing LIMIT to the temporary table creation is not applicable
+      when there is ORDER BY or GROUP BY or there is no GROUP BY, but
+      there are aggregate functions, because in all these cases we need
+      all result rows.
+    */
+    ha_rows tmp_rows_limit= ((order == 0 || skip_sort_order ||
+                              test(select_options & OPTION_BUFFER_RESULT)) &&
+                             !tmp_group &&
+                             !thd->lex->current_select->with_sum_func) ?
+                            select_limit : HA_POS_ERROR;
+
     if (!(exec_tmp_table1 =
 	  create_tmp_table(thd, &tmp_table_param, all_fields,
-			   ((!simple_group && !procedure &&
-			     !(test_flags & TEST_NO_KEY_GROUP)) ?
-			    group_list : (ORDER*) 0),
+                           tmp_group,
 			   group_list ? 0 : select_distinct,
 			   group_list && simple_group,
 			   select_options,
-			   (order == 0 || skip_sort_order || 
-                            test(select_options & OPTION_BUFFER_RESULT)) ? 
-                             select_limit : HA_POS_ERROR,
+                           tmp_rows_limit,
 			   (char *) "")))
       DBUG_RETURN(1);
 
@@ -5567,6 +5578,13 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 			  thd->variables.max_heap_table_size) :
 		      thd->variables.tmp_table_size)/ table->reclength);
   set_if_bigger(table->max_rows,1);		// For dummy start options
+  /*
+    Push the LIMIT clause to the temporary table creation, so that we
+    materialize only up to 'rows_limit' records instead of all result records.
+  */
+  set_if_smaller(table->max_rows, rows_limit);
+  param->end_write_records= rows_limit;
+
   keyinfo=param->keyinfo;
 
   if (group)
@@ -5687,19 +5705,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
     }
   }
 
-  /*
-    Push the LIMIT clause to the temporary table creation, so that we
-    materialize only up to 'rows_limit' records instead of all result records.
-    This optimization is not applicable when there is GROUP BY or there is
-    no GROUP BY, but there are aggregate functions, because both must be
-    computed for all result rows.
-  */
-  if (!group && !thd->lex->current_select->with_sum_func)
-  {
-    set_if_smaller(table->max_rows, rows_limit);
-    param->end_write_records= rows_limit;
-  }
-
   if (thd->is_fatal_error)				// If end of memory
     goto err;					 /* purecov: inspected */
   table->db_record_offset=1;
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index a5cb0d45664..da66b556b5e 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -214,7 +214,7 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
   bool some_tables_deleted=0, tmp_table_deleted=0, foreign_key_error=0;
   DBUG_ENTER("mysql_rm_table_part2");
 
-  if (lock_table_names(thd, tables))
+  if (!drop_temporary && lock_table_names(thd, tables))
     DBUG_RETURN(1);
 
   for (table=tables ; table ; table=table->next)
@@ -311,7 +311,8 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
     }
   }
 
-  unlock_table_names(thd, tables);
+  if (!drop_temporary)
+    unlock_table_names(thd, tables);
   DBUG_RETURN(error);
 }