diff --git a/extern/storage-sealing/sealing.go b/extern/storage-sealing/sealing.go
index c18dc88fa..25397ecfb 100644
--- a/extern/storage-sealing/sealing.go
+++ b/extern/storage-sealing/sealing.go
@@ -283,29 +283,52 @@ func (m *Sealing) StartPacking(sectorID abi.SectorNumber) error {
 
 // Caller should hold m.unsealedInfoMap.lk
 func (m *Sealing) getSectorAndPadding(ctx context.Context, size abi.UnpaddedPieceSize) (abi.SectorNumber, []abi.PaddedPieceSize, error) {
-	for k, v := range m.unsealedInfoMap.infos {
-		pads, padLength := ffiwrapper.GetRequiredPadding(v.stored, size.Padded())
+	for tries := 0; tries < 100; tries++ {
+		for k, v := range m.unsealedInfoMap.infos {
+			pads, padLength := ffiwrapper.GetRequiredPadding(v.stored, size.Padded())
 
-		if v.stored+size.Padded()+padLength <= abi.PaddedPieceSize(v.ssize) {
-			return k, pads, nil
+			if v.stored+size.Padded()+padLength <= abi.PaddedPieceSize(v.ssize) {
+				return k, pads, nil
+			}
 		}
+
+		if len(m.unsealedInfoMap.infos) > 0 {
+			log.Infow("tried to put a piece into an open sector, found none with enough space", "open", len(m.unsealedInfoMap.infos), "size", size, "tries", tries)
+		}
+
+		ns, ssize, err := m.newDealSector(ctx)
+		switch err {
+		case nil:
+			m.unsealedInfoMap.infos[ns] = UnsealedSectorInfo{
+				numDeals:   0,
+				stored:     0,
+				pieceSizes: nil,
+				ssize:      ssize,
+			}
+		case errTooManySealing:
+			m.unsealedInfoMap.lk.Unlock()
+
+			select {
+			case <-time.After(2 * time.Second):
+			case <-ctx.Done():
+				m.unsealedInfoMap.lk.Lock()
+				return 0, nil, xerrors.Errorf("getting sector for piece: %w", ctx.Err())
+			}
+
+			m.unsealedInfoMap.lk.Lock()
+			continue
+		default:
+			return 0, nil, xerrors.Errorf("creating new sector: %w", err)
+		}
+
+		return ns, nil, nil
 	}
 
-	ns, ssize, err := m.newDealSector(ctx)
-	if err != nil {
-		return 0, nil, err
-	}
-
-	m.unsealedInfoMap.infos[ns] = UnsealedSectorInfo{
-		numDeals:   0,
-		stored:     0,
-		pieceSizes: nil,
-		ssize:      ssize,
-	}
-
-	return ns, nil, nil
+	return 0, nil, xerrors.Errorf("failed to allocate piece to a sector")
 }
 
+var errTooManySealing = errors.New("too many sectors sealing")
+
 // newDealSector creates a new sector for deal storage
 func (m *Sealing) newDealSector(ctx context.Context) (abi.SectorNumber, abi.SectorSize, error) {
 	// First make sure we don't have too many 'open' sectors
@@ -321,47 +344,34 @@ func (m *Sealing) newDealSector(ctx context.Context) (abi.SectorNumber, abi.Sect
 		}
 	}
 
-	if cfg.MaxWaitDealsSectors > 0 {
-		// run in a loop because we have to drop the map lock here for a bit
-		tries := 0
+	if cfg.MaxWaitDealsSectors > 0 && uint64(len(m.unsealedInfoMap.infos)) >= cfg.MaxWaitDealsSectors {
+		// Too many sectors are sealing in parallel. Start sealing one, and retry
+		// allocating the piece to a sector (we're dropping the lock here, so in
+		// case other goroutines are also trying to create a sector, we retry in
+		// getSectorAndPadding instead of here - otherwise if we have lots of
+		// parallel deals in progress, we can start creating a ton of sectors
+		// with just a single deal in them)
+		var mostStored abi.PaddedPieceSize = math.MaxUint64
+		var best abi.SectorNumber = math.MaxUint64
 
-		// we have to run in a loop as we're dropping unsealedInfoMap.lk
-		//  to actually call StartPacking. When we do that, another entry can
-		//  get added to unsealedInfoMap.
-		for uint64(len(m.unsealedInfoMap.infos)) >= cfg.MaxWaitDealsSectors {
-			if tries > 10 {
-				// whatever...
-				break
+		for sn, info := range m.unsealedInfoMap.infos {
+			if info.stored+1 > mostStored+1 { // 18446744073709551615 + 1 = 0
+				best = sn
 			}
-
-			if tries > 0 {
-				m.unsealedInfoMap.lk.Unlock()
-				time.Sleep(time.Second)
-				m.unsealedInfoMap.lk.Lock()
-			}
-
-			tries++
-			var mostStored abi.PaddedPieceSize = math.MaxUint64
-			var best abi.SectorNumber = math.MaxUint64
-
-			for sn, info := range m.unsealedInfoMap.infos {
-				if info.stored+1 > mostStored+1 { // 18446744073709551615 + 1 = 0
-					best = sn
-				}
-			}
-
-			if best == math.MaxUint64 {
-				// probably not possible, but who knows
-				break
-			}
-
-			m.unsealedInfoMap.lk.Unlock()
-			if err := m.StartPacking(best); err != nil {
-				log.Errorf("newDealSector StartPacking error: %+v", err)
-				continue // let's pretend this is fine
-			}
-			m.unsealedInfoMap.lk.Lock()
 		}
+
+		if best != math.MaxUint64 {
+			m.unsealedInfoMap.lk.Unlock()
+			err := m.StartPacking(best)
+			m.unsealedInfoMap.lk.Lock()
+
+			if err != nil {
+				log.Errorf("newDealSector StartPacking error: %+v", err)
+				// let's pretend this is fine
+			}
+		}
+
+		return 0, 0, errTooManySealing // will wait a bit and retry
 	}
 
 	spt, err := m.currentSealProof(ctx)