Merge pull request #663 from cfromknecht/utxn-height-hint

Fix UtxoNursery Commit Sweep Height-Hint

channeldb/db.go

@@ -9,6 +9,7 @@ import (
 	"sync"
 
 	"github.com/boltdb/bolt"
+	"github.com/go-errors/errors"
 	"github.com/roasbeef/btcd/btcec"
 	"github.com/roasbeef/btcd/wire"
 )
@@ -434,6 +435,42 @@ func (d *DB) FetchClosedChannels(pendingOnly bool) ([]*ChannelCloseSummary, erro
 	return chanSummaries, nil
 }
 
+// ErrClosedChannelNotFound signals that a closed channel could not be found in
+// the channeldb.
+var ErrClosedChannelNotFound = errors.New("unable to find closed channel summary")
+
+// FetchClosedChannel queries for a channel close summary using the channel
+// point of the channel in question.
+func (d *DB) FetchClosedChannel(chanID *wire.OutPoint) (*ChannelCloseSummary, error) {
+	var chanSummary *ChannelCloseSummary
+	if err := d.View(func(tx *bolt.Tx) error {
+		closeBucket := tx.Bucket(closedChannelBucket)
+		if closeBucket == nil {
+			return ErrClosedChannelNotFound
+		}
+
+		var b bytes.Buffer
+		var err error
+		if err = writeOutpoint(&b, chanID); err != nil {
+			return err
+		}
+
+		summaryBytes := closeBucket.Get(b.Bytes())
+		if summaryBytes == nil {
+			return ErrClosedChannelNotFound
+		}
+
+		summaryReader := bytes.NewReader(summaryBytes)
+		chanSummary, err = deserializeCloseChannelSummary(summaryReader)
+
+		return err
+	}); err != nil {
+		return nil, err
+	}
+
+	return chanSummary, nil
+}
+
 // MarkChanFullyClosed marks a channel as fully closed within the database. A
 // channel should be marked as fully closed if the channel was initially
 // cooperatively closed and it's reach a single confirmation, or after all the

utxonursery.go

@@ -302,7 +302,7 @@ func (u *utxoNursery) Start() error {
 	// NOTE: The next two steps *may* spawn go routines, thus from this
 	// point forward, we must close the nursery's quit channel if we detect
 	// any failures during startup to ensure they terminate.
-	if err := u.reloadPreschool(lastGraduatedHeight); err != nil {
+	if err := u.reloadPreschool(); err != nil {
 		newBlockChan.Cancel()
 		close(u.quit)
 		return err
@@ -608,14 +608,39 @@ func (u *utxoNursery) NurseryReport(
 
 // reloadPreschool re-initializes the chain notifier with all of the outputs
 // that had been saved to the "preschool" database bucket prior to shutdown.
-func (u *utxoNursery) reloadPreschool(heightHint uint32) error {
+func (u *utxoNursery) reloadPreschool() error {
 	psclOutputs, err := u.cfg.Store.FetchPreschools()
 	if err != nil {
 		return err
 	}
 
+	// For each of the preschool outputs stored in the nursery store, load
+	// it's close summary from disk so that we can get an accurate height
+	// hint from which to start our range for spend notifications.
 	for i := range psclOutputs {
-		err := u.registerPreschoolConf(&psclOutputs[i], heightHint)
+		kid := &psclOutputs[i]
+		chanPoint := kid.OriginChanPoint()
+
+		// Load the close summary for this output's channel point.
+		closeSummary, err := u.cfg.DB.FetchClosedChannel(chanPoint)
+		if err == channeldb.ErrClosedChannelNotFound {
+			// This should never happen since the close summary
+			// should only be removed after the channel has been
+			// swept completely.
+			utxnLog.Warnf("Close summary not found for "+
+				"chan_point=%v, can't determine height hint"+
+				"to sweep commit txn", chanPoint)
+			continue
+
+		} else if err != nil {
+			return err
+		}
+
+		// Use the close height from the channel summary as our height
+		// hint to drive our spend notifications, with our confirmation
+		// depth as a buffer for reorgs.
+		heightHint := closeSummary.CloseHeight - u.cfg.ConfDepth
+		err = u.registerPreschoolConf(kid, heightHint)
 		if err != nil {
 			return err
 		}