ETNA_PREP_WRITE
if (args->op & ~(ETNA_PREP_READ | ETNA_PREP_WRITE | ETNA_PREP_NOSYNC))
op &= ETNA_PREP_READ | ETNA_PREP_WRITE;
else if (op == ETNA_PREP_WRITE)
bool write = !!(op & ETNA_PREP_WRITE);