EXT_MAX_EXTENT
len = EXT_MAX_EXTENT(eh) - nearex;
len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
if (path[depth].ep_ext > EXT_MAX_EXTENT(path[depth].ep_header)) {
if (path[depth].ep_ext != EXT_MAX_EXTENT(path[depth].ep_header))
while (path[depth].ep_ext <= EXT_MAX_EXTENT(path[depth].ep_header)) {