ext4_ext_map_blocks
extern int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
retval = ext4_ext_map_blocks(handle, inode, map, 0);
retval = ext4_ext_map_blocks(handle, inode, &map2, 0);
retval = ext4_ext_map_blocks(handle, inode, map, flags);
retval = ext4_ext_map_blocks(handle, inode, map, flags);