XFS_RMAP_BLOCK_LEN
blocklen -= XFS_RMAP_BLOCK_LEN;
((char *)(block) + XFS_RMAP_BLOCK_LEN + \
((char *)(block) + XFS_RMAP_BLOCK_LEN + \
((char *)(block) + XFS_RMAP_BLOCK_LEN + \
((char *)(block) + XFS_RMAP_BLOCK_LEN + \