diff --git a/extern/sector-storage/ffiwrapper/sealer_cgo.go b/extern/sector-storage/ffiwrapper/sealer_cgo.go
index 816a025e9..400b67211 100644
--- a/extern/sector-storage/ffiwrapper/sealer_cgo.go
+++ b/extern/sector-storage/ffiwrapper/sealer_cgo.go
@@ -58,14 +58,6 @@ func (sb *Sealer) DataCid(ctx context.Context, pieceSize abi.UnpaddedPieceSize,
 
 	maxSizeSpt := abi.RegisteredSealProof_StackedDrg64GiBV1_1
 
-	var done func()
-
-	defer func() {
-		if done != nil {
-			done()
-		}
-	}()
-
 	throttle := make(chan []byte, parallel)
 	piecePromises := make([]func() (abi.PieceInfo, error), 0)
 
@@ -123,7 +115,7 @@ func (sb *Sealer) DataCid(ctx context.Context, pieceSize abi.UnpaddedPieceSize,
 				}
 
 				return abi.PieceInfo{
-					Size:     abi.UnpaddedPieceSize(len(buf[:read])).Padded(),
+					Size:     abi.UnpaddedPieceSize(read).Padded(),
 					PieceCID: e.Cid,
 				}, nil
 			case <-ctx.Done():
diff --git a/itests/worker_test.go b/itests/worker_test.go
index 59d1407fd..12fc96417 100644
--- a/itests/worker_test.go
+++ b/itests/worker_test.go
@@ -54,6 +54,12 @@ func TestWorkerDataCid(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, abi.PaddedPieceSize(1024), pi.Size)
 	require.Equal(t, "baga6ea4seaqlhznlutptgfwhffupyer6txswamerq5fc2jlwf2lys2mm5jtiaeq", pi.PieceCID.String())
+
+	bigPiece := abi.PaddedPieceSize(16 << 20).Unpadded()
+	pi, err = miner.ComputeDataCid(ctx, bigPiece, strings.NewReader(strings.Repeat("a", int(bigPiece))))
+	require.NoError(t, err)
+	require.Equal(t, bigPiece.Padded(), pi.Size)
+	require.Equal(t, "baga6ea4seaqmhoxl2ybw5m2wyd3pt3h4zmp7j52yumzu2rar26twns3uocq7yfa", pi.PieceCID.String())
 }
 
 func TestWinningPostWorker(t *testing.T) {