From 62e19185f14356898e92bd10f03194e9b7aa1e9b Mon Sep 17 00:00:00 2001
From: eugene <elzeigel@gmail.com>
Date: Wed, 19 Aug 2020 10:52:44 -0400
Subject: [PATCH] htlcswitch+channeldb: single tx for removing fwdpkgs

This commit changes RemoveFwdPkg to RemoveFwdPkgs so that a single
tx is used instead of N where N is the number of fwd pkgs to remove.
---
 channeldb/channel.go | 16 ++++++++++++----
 htlcswitch/link.go   |  4 ++--
 lnwallet/channel.go  |  6 +++---
 3 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/channeldb/channel.go b/channeldb/channel.go
index 5d943a11..0a5e47b2 100644
--- a/channeldb/channel.go
+++ b/channeldb/channel.go
@@ -2409,16 +2409,24 @@ func (c *OpenChannel) SetFwdFilter(height uint64, fwdFilter *PkgFilter) error {
 	})
 }
 
-// RemoveFwdPkg atomically removes a forwarding package specified by the remote
-// commitment height.
+// RemoveFwdPkgs atomically removes forwarding packages specified by the remote
+// commitment heights. If one of the intermediate RemovePkg calls fails, then the
+// later packages won't be removed.
 //
 // NOTE: This method should only be called on packages marked FwdStateCompleted.
-func (c *OpenChannel) RemoveFwdPkg(height uint64) error {
+func (c *OpenChannel) RemoveFwdPkgs(heights ...uint64) error {
 	c.Lock()
 	defer c.Unlock()
 
 	return kvdb.Update(c.Db, func(tx kvdb.RwTx) error {
-		return c.Packager.RemovePkg(tx, height)
+		for _, height := range heights {
+			err := c.Packager.RemovePkg(tx, height)
+			if err != nil {
+				return err
+			}
+		}
+
+		return nil
 	})
 }
 
diff --git a/htlcswitch/link.go b/htlcswitch/link.go
index 3931af34..d9ee8db3 100644
--- a/htlcswitch/link.go
+++ b/htlcswitch/link.go
@@ -776,7 +776,7 @@ func (l *channelLink) resolveFwdPkg(fwdPkg *channeldb.FwdPkg) error {
 		l.log.Debugf("removing completed fwd pkg for height=%d",
 			fwdPkg.Height)
 
-		err := l.channel.RemoveFwdPkg(fwdPkg.Height)
+		err := l.channel.RemoveFwdPkgs(fwdPkg.Height)
 		if err != nil {
 			l.log.Errorf("unable to remove fwd pkg for height=%d: "+
 				"%v", fwdPkg.Height, err)
@@ -859,7 +859,7 @@ func (l *channelLink) fwdPkgGarbager() {
 					continue
 				}
 
-				err = l.channel.RemoveFwdPkg(fwdPkg.Height)
+				err = l.channel.RemoveFwdPkgs(fwdPkg.Height)
 				if err != nil {
 					l.log.Warnf("unable to remove fwd pkg "+
 						"for height=%d: %v",
diff --git a/lnwallet/channel.go b/lnwallet/channel.go
index 563fe8d1..94e26805 100644
--- a/lnwallet/channel.go
+++ b/lnwallet/channel.go
@@ -4850,9 +4850,9 @@ func (lc *LightningChannel) SetFwdFilter(height uint64,
 	return lc.channelState.SetFwdFilter(height, fwdFilter)
 }
 
-// RemoveFwdPkg permanently deletes the forwarding package at the given height.
-func (lc *LightningChannel) RemoveFwdPkg(height uint64) error {
-	return lc.channelState.RemoveFwdPkg(height)
+// RemoveFwdPkgs permanently deletes the forwarding package at the given heights.
+func (lc *LightningChannel) RemoveFwdPkgs(heights ...uint64) error {
+	return lc.channelState.RemoveFwdPkgs(heights...)
 }
 
 // NextRevocationKey returns the commitment point for the _next_ commitment