udf_check_anchor_block
ret = udf_check_anchor_block(sb, sbi->s_anchor, fileset);
ret = udf_check_anchor_block(sb, sbi->s_session + 256, fileset);
ret = udf_check_anchor_block(sb, last[i], fileset);
ret = udf_check_anchor_block(sb, last[i] - 256, fileset);
return udf_check_anchor_block(sb, sbi->s_session + 512, fileset);