static inline void cow_set_bits(uint8_t *bitmap, int start, int64_t nb_sectors) { int64_t bitnum = start, last = start + nb_sectors; while (bitnum < last) { if ((bitnum & 7) == 0 && bitnum + 8 <= last) { bitmap[bitnum / 8] = 0xFF; bitnum += 8; continue; } bitmap[bitnum/8] |= (1 << (bitnum % 8)); bitnum++; } }