diff --git a/node/impl/storminer.go b/node/impl/storminer.go
index 49c807412..f339fd66a 100644
--- a/node/impl/storminer.go
+++ b/node/impl/storminer.go
@@ -35,7 +35,7 @@ func (sm *StorageMinerAPI) ActorAddress(context.Context) (address.Address, error
 }
 
 func (sm *StorageMinerAPI) StoreGarbageData(ctx context.Context) error {
-	return sm.Miner.StoreGarbageData(ctx)
+	return sm.Miner.StoreGarbageData()
 }
 
 func (sm *StorageMinerAPI) SectorsStatus(ctx context.Context, sid uint64) (api.SectorInfo, error) {
diff --git a/storage/garbage.go b/storage/garbage.go
index 28e33e77d..f61ff50cc 100644
--- a/storage/garbage.go
+++ b/storage/garbage.go
@@ -62,7 +62,6 @@ func (m *Miner) storeGarbage(ctx context.Context, sectorID uint64, existingPiece
 		return nil, xerrors.Errorf("serializing PublishStorageDeals params failed: ", aerr)
 	}
 
-	// TODO: We may want this to happen after fetching data
 	smsg, err := m.api.MpoolPushMessage(ctx, &types.Message{
 		To:       actors.StorageMarketAddress,
 		From:     m.worker,
@@ -112,9 +111,12 @@ func (m *Miner) storeGarbage(ctx context.Context, sectorID uint64, existingPiece
 	return out, nil
 }
 
-func (m *Miner) StoreGarbageData(_ context.Context) error {
-	ctx := context.TODO()
+func (m *Miner) StoreGarbageData() error {
 	go func() {
+		ctx := context.TODO() // we can't use the context from command which invokes
+		// this, as we run everything here async, and it's cancelled when the
+		// command exits
+
 		size := sectorbuilder.UserBytesForSectorSize(m.sb.SectorSize())
 
 		sid, err := m.sb.AcquireSectorId()
diff --git a/storage/sealing_utils.go b/storage/sealing_utils.go
index 26591e0ac..d8d5225bb 100644
--- a/storage/sealing_utils.go
+++ b/storage/sealing_utils.go
@@ -7,13 +7,36 @@ import (
 )
 
 func fillersFromRem(toFill uint64) ([]uint64, error) {
-	toFill += toFill / 127 // convert to in-sector bytes for easier math
+	// Convert to in-sector bytes for easier math:
+	//
+	// Sector size to user bytes ratio is constant, e.g. for 1024B we have 1016B
+	// of user-usable data.
+	//
+	// (1024/1016 = 128/127)
+	//
+	// Given that we can get sector size by simply adding 1/127 of the user
+	// bytes
+	//
+	// (we convert to sector bytes as they are nice round binary numbers)
 
+	toFill += toFill / 127
+
+	// We need to fill the sector with pieces that are powers of 2. Conveniently
+	// computers store numbers in binary, which means we can look at 1s to get
+	// all the piece sizes we need to fill the sector. It also means that number
+	// of pieces is the number of 1s in the number of remaining bytes to fill
 	out := make([]uint64, bits.OnesCount64(toFill))
 	for i := range out {
+		// Extract the next lowest non-zero bit
 		next := bits.TrailingZeros64(toFill)
 		psize := uint64(1) << next
+		// e.g: if the number is 0b010100, psize will be 0b000100
+
+		// set that bit to 0 by XORing it, so the next iteration looks at the
+		// next bit
 		toFill ^= psize
+
+		// Add the piece size to the list of pieces we need to create
 		out[i] = sectorbuilder.UserBytesForSectorSize(psize)
 	}
 	return out, nil