xfs_bmbt_disk_get_blockcount
xfs_bmbt_disk_get_blockcount(&last) <=
xfs_bmbt_disk_get_blockcount(ep) <=
xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
extern xfs_filblks_t xfs_bmbt_disk_get_blockcount(const struct xfs_bmbt_rec *r);