}
#define BLOCKS_PER_MAP (8 * sizeof(long))
-#define TO_MAP_BLOCK(td, f, b) ((b) - ((f)->file_offset / (td)->o.rw_min_bs))
+#define TO_MAP_BLOCK(td, f, b) ((b) - ((f)->file_offset / (unsigned long long) (td)->o.rw_min_bs))
#define RAND_MAP_IDX(td, f, b) (TO_MAP_BLOCK(td, f, b) / BLOCKS_PER_MAP)
#define RAND_MAP_BIT(td, f, b) (TO_MAP_BLOCK(td, f, b) & (BLOCKS_PER_MAP - 1))