Local merge.

mysql-test/r/lowercase_mixed_tmpdir_innodb.result

+drop table if exists t1;
+create table t1 (id int) engine=InnoDB;
+insert into t1 values (1);
+create temporary table t2 engine=InnoDB select * from t1;
+drop temporary table t2;
+drop table t1;

mysql-test/t/lowercase_mixed_tmpdir_innodb-master.opt

+--lower-case-table-names=2
+--tmpdir=$MYSQLTEST_VARDIR/tmp/MixedCase

mysql-test/t/lowercase_mixed_tmpdir_innodb-master.sh

+# This test requires a non-lowercase tmpdir directory on a case-sensitive
+# filesystem.
+
+d="$MYSQLTEST_VARDIR/tmp/MixedCase"
+test -d "$d" || mkdir "$d"
+rm -f "$d"/*

mysql-test/t/lowercase_mixed_tmpdir_innodb.test

+--source include/have_lowercase2.inc
+--source include/have_innodb.inc
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+create table t1 (id int) engine=InnoDB;
+insert into t1 values (1);
+create temporary table t2 engine=InnoDB select * from t1;
+drop temporary table t2;
+drop table t1;

sql/handler.cc

@@ -1885,12 +1885,42 @@ bool ha_flush_logs(handlerton *db_type)
   return FALSE;
 }
 
+
+/**
+  @brief make canonical filename
+
+  @param[in]  file     table handler
+  @param[in]  path     original path
+  @param[out] tmp_path buffer for canonized path
+
+  @details Lower case db name and table name path parts for
+           non file based tables when lower_case_table_names
+           is 2 (store as is, compare in lower case).
+           Filesystem path prefix (mysql_data_home or tmpdir)
+           is left intact.
+
+  @note tmp_path may be left intact if no conversion was
+        performed.
+
+  @retval canonized path
+
+  @todo This may be done more efficiently when table path
+        gets built. Convert this function to something like
+        ASSERT_CANONICAL_FILENAME.
+*/
 const char *get_canonical_filename(handler *file, const char *path,
                                    char *tmp_path)
 {
+  uint i;
   if (lower_case_table_names != 2 || (file->ha_table_flags() & HA_FILE_BASED))
     return path;
 
+  for (i= 0; i <= mysql_tmpdir_list.max; i++)
+  {
+    if (is_prefix(path, mysql_tmpdir_list.list[i]))
+      return path;
+  }
+
   /* Ensure that table handler get path in lower case */
   if (tmp_path != path)
     strmov(tmp_path, path);