XFS_RMAP_OFF
oinfo->oi_offset = XFS_RMAP_OFF(offset);
x = XFS_RMAP_OFF(irec->rm_offset);
irec->rm_offset = XFS_RMAP_OFF(offset);
off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);