XFS_DFORK_FORMAT
uint32_t fork_format = XFS_DFORK_FORMAT(dip, whichfork);
if (XFS_DFORK_FORMAT(dip, XFS_DATA_FORK) != XFS_DINODE_FMT_META_BTREE) {
fmt = XFS_DFORK_FORMAT(dip, XFS_DATA_FORK);
switch (XFS_DFORK_FORMAT(dip, XFS_ATTR_FORK)) {