uint64_t waiting_for_zero_pos;
interval_set<uint64_t> pending_zero; // non-contig bits we've zeroed
+ list<Context*> waitfor_prezero;
+
std::map<uint64_t, uint64_t> pending_safe; // flush_pos -> safe_pos
// when safe through given offset
std::map<uint64_t, std::list<Context*> > waitfor_safe;
void flush(Context *onsafe = 0);
void wait_for_readable(Context *onfinish);
bool have_waiter() const;
+ void wait_for_prezero(Context *onfinish);
// Synchronous setters
// ===================