From 3f775778c391af533885574f2ed0cef80a68f978 Mon Sep 17 00:00:00 2001
From: Joost Jager <joost.jager@gmail.com>
Date: Mon, 23 Aug 2021 12:16:37 +0200
Subject: [PATCH 1/2] channeldb+routing: add tx parameter

Adds an optional tx parameter to ForAllOutgoingChannels and FetchChannel
so that data can be queried within the context of an existing database
transaction.
---
 chanbackup/backup.go               |  8 +++++---
 chanbackup/backup_test.go          |  5 ++++-
 channeldb/db.go                    | 15 ++++++++++++---
 channeldb/db_test.go               |  8 ++++----
 channelnotifier/channelnotifier.go |  2 +-
 contractcourt/chain_arbitrator.go  |  4 ++--
 discovery/gossiper.go              |  2 ++
 discovery/gossiper_test.go         |  9 +++++++--
 pilot.go                           |  2 +-
 routing/localchans/manager.go      | 14 +++++++++-----
 routing/localchans/manager_test.go |  9 ++++++---
 routing/router.go                  | 12 +++++++-----
 rpcserver.go                       |  4 ++--
 13 files changed, 62 insertions(+), 32 deletions(-)

diff --git a/chanbackup/backup.go b/chanbackup/backup.go
index b956c6fa9..076e2fcf6 100644
--- a/chanbackup/backup.go
+++ b/chanbackup/backup.go
@@ -7,6 +7,7 @@ import (
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/kvdb"
 )
 
 // LiveChannelSource is an interface that allows us to query for the set of
@@ -17,8 +18,9 @@ type LiveChannelSource interface {
 	FetchAllChannels() ([]*channeldb.OpenChannel, error)
 
 	// FetchChannel attempts to locate a live channel identified by the
-	// passed chanPoint.
-	FetchChannel(chanPoint wire.OutPoint) (*channeldb.OpenChannel, error)
+	// passed chanPoint. Optionally an existing db tx can be supplied.
+	FetchChannel(tx kvdb.RTx, chanPoint wire.OutPoint) (
+		*channeldb.OpenChannel, error)
 
 	// AddrsForNode returns all known addresses for the target node public
 	// key.
@@ -55,7 +57,7 @@ func FetchBackupForChan(chanPoint wire.OutPoint,
 
 	// First, we'll query the channel source to see if the channel is known
 	// and open within the database.
-	targetChan, err := chanSource.FetchChannel(chanPoint)
+	targetChan, err := chanSource.FetchChannel(nil, chanPoint)
 	if err != nil {
 		// If we can't find the channel, then we return with an error,
 		// as we have nothing to  backup.
diff --git a/chanbackup/backup_test.go b/chanbackup/backup_test.go
index ea8bfceac..e718dce3e 100644
--- a/chanbackup/backup_test.go
+++ b/chanbackup/backup_test.go
@@ -8,6 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/kvdb"
 )
 
 type mockChannelSource struct {
@@ -38,7 +39,9 @@ func (m *mockChannelSource) FetchAllChannels() ([]*channeldb.OpenChannel, error)
 	return chans, nil
 }
 
-func (m *mockChannelSource) FetchChannel(chanPoint wire.OutPoint) (*channeldb.OpenChannel, error) {
+func (m *mockChannelSource) FetchChannel(_ kvdb.RTx, chanPoint wire.OutPoint) (
+	*channeldb.OpenChannel, error) {
+
 	if m.failQuery {
 		return nil, fmt.Errorf("fail")
 	}
diff --git a/channeldb/db.go b/channeldb/db.go
index e1a29dc1c..530c819a1 100644
--- a/channeldb/db.go
+++ b/channeldb/db.go
@@ -501,7 +501,11 @@ func (d *DB) fetchNodeChannels(chainBucket kvdb.RBucket) ([]*OpenChannel, error)
 
 // FetchChannel attempts to locate a channel specified by the passed channel
 // point. If the channel cannot be found, then an error will be returned.
-func (d *DB) FetchChannel(chanPoint wire.OutPoint) (*OpenChannel, error) {
+// Optionally an existing db tx can be supplied. Optionally an existing db tx
+// can be supplied.
+func (d *DB) FetchChannel(tx kvdb.RTx, chanPoint wire.OutPoint) (*OpenChannel,
+	error) {
+
 	var (
 		targetChan      *OpenChannel
 		targetChanPoint bytes.Buffer
@@ -583,7 +587,12 @@ func (d *DB) FetchChannel(chanPoint wire.OutPoint) (*OpenChannel, error) {
 		})
 	}
 
-	err := kvdb.View(d, chanScan, func() {})
+	var err error
+	if tx == nil {
+		err = kvdb.View(d, chanScan, func() {})
+	} else {
+		err = chanScan(tx)
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -1102,7 +1111,7 @@ func (d *DB) AbandonChannel(chanPoint *wire.OutPoint, bestHeight uint32) error {
 	// With the chanPoint constructed, we'll attempt to find the target
 	// channel in the database. If we can't find the channel, then we'll
 	// return the error back to the caller.
-	dbChan, err := d.FetchChannel(*chanPoint)
+	dbChan, err := d.FetchChannel(nil, *chanPoint)
 	switch {
 	// If the channel wasn't found, then it's possible that it was already
 	// abandoned from the database.
diff --git a/channeldb/db_test.go b/channeldb/db_test.go
index ed357e5e4..60e82e680 100644
--- a/channeldb/db_test.go
+++ b/channeldb/db_test.go
@@ -255,7 +255,7 @@ func TestFetchChannel(t *testing.T) {
 	channelState := createTestChannel(t, cdb, openChannelOption())
 
 	// Next, attempt to fetch the channel by its chan point.
-	dbChannel, err := cdb.FetchChannel(channelState.FundingOutpoint)
+	dbChannel, err := cdb.FetchChannel(nil, channelState.FundingOutpoint)
 	if err != nil {
 		t.Fatalf("unable to fetch channel: %v", err)
 	}
@@ -275,7 +275,7 @@ func TestFetchChannel(t *testing.T) {
 	}
 	channelState2.FundingOutpoint.Index ^= 1
 
-	_, err = cdb.FetchChannel(channelState2.FundingOutpoint)
+	_, err = cdb.FetchChannel(nil, channelState2.FundingOutpoint)
 	if err == nil {
 		t.Fatalf("expected query to fail")
 	}
@@ -416,7 +416,7 @@ func TestRestoreChannelShells(t *testing.T) {
 
 	// We should also be able to find the channel if we query for it
 	// directly.
-	_, err = cdb.FetchChannel(channelShell.Chan.FundingOutpoint)
+	_, err = cdb.FetchChannel(nil, channelShell.Chan.FundingOutpoint)
 	if err != nil {
 		t.Fatalf("unable to fetch channel: %v", err)
 	}
@@ -470,7 +470,7 @@ func TestAbandonChannel(t *testing.T) {
 
 	// At this point, the channel should no longer be found in the set of
 	// open channels.
-	_, err = cdb.FetchChannel(chanState.FundingOutpoint)
+	_, err = cdb.FetchChannel(nil, chanState.FundingOutpoint)
 	if err != ErrChannelNotFound {
 		t.Fatalf("channel should not have been found: %v", err)
 	}
diff --git a/channelnotifier/channelnotifier.go b/channelnotifier/channelnotifier.go
index df062c437..b99d18d40 100644
--- a/channelnotifier/channelnotifier.go
+++ b/channelnotifier/channelnotifier.go
@@ -134,7 +134,7 @@ func (c *ChannelNotifier) NotifyPendingOpenChannelEvent(chanPoint wire.OutPoint,
 // channel has gone from pending open to open.
 func (c *ChannelNotifier) NotifyOpenChannelEvent(chanPoint wire.OutPoint) {
 	// Fetch the relevant channel from the database.
-	channel, err := c.chanDB.FetchChannel(chanPoint)
+	channel, err := c.chanDB.FetchChannel(nil, chanPoint)
 	if err != nil {
 		log.Warnf("Unable to fetch open channel from the db: %v", err)
 	}
diff --git a/contractcourt/chain_arbitrator.go b/contractcourt/chain_arbitrator.go
index f653ebcad..2ddc9c8cd 100644
--- a/contractcourt/chain_arbitrator.go
+++ b/contractcourt/chain_arbitrator.go
@@ -258,7 +258,7 @@ func (a *arbChannel) NewAnchorResolutions() (*lnwallet.AnchorResolutions,
 	// same instance that is used by the link.
 	chanPoint := a.channel.FundingOutpoint
 
-	channel, err := a.c.chanSource.FetchChannel(chanPoint)
+	channel, err := a.c.chanSource.FetchChannel(nil, chanPoint)
 	if err != nil {
 		return nil, err
 	}
@@ -301,7 +301,7 @@ func (a *arbChannel) ForceCloseChan() (*lnwallet.LocalForceCloseSummary, error)
 	// Now that we know the link can't mutate the channel
 	// state, we'll read the channel from disk the target
 	// channel according to its channel point.
-	channel, err := a.c.chanSource.FetchChannel(chanPoint)
+	channel, err := a.c.chanSource.FetchChannel(nil, chanPoint)
 	if err != nil {
 		return nil, err
 	}
diff --git a/discovery/gossiper.go b/discovery/gossiper.go
index 66174c05a..d7f2fd5fc 100644
--- a/discovery/gossiper.go
+++ b/discovery/gossiper.go
@@ -15,6 +15,7 @@ import (
 	"github.com/lightningnetwork/lnd/batch"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -1210,6 +1211,7 @@ func (d *AuthenticatedGossiper) retransmitStaleAnns(now time.Time) error {
 		edgesToUpdate      []updateTuple
 	)
 	err := d.cfg.Router.ForAllOutgoingChannels(func(
+		_ kvdb.RTx,
 		info *channeldb.ChannelEdgeInfo,
 		edge *channeldb.ChannelEdgePolicy) error {
 
diff --git a/discovery/gossiper_test.go b/discovery/gossiper_test.go
index c12b9b532..55563018c 100644
--- a/discovery/gossiper_test.go
+++ b/discovery/gossiper_test.go
@@ -25,6 +25,7 @@ import (
 	"github.com/lightningnetwork/lnd/batch"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnpeer"
 	"github.com/lightningnetwork/lnd/lntest/mock"
 	"github.com/lightningnetwork/lnd/lntest/wait"
@@ -200,7 +201,8 @@ func (r *mockGraphSource) ForEachNode(func(node *channeldb.LightningNode) error)
 	return nil
 }
 
-func (r *mockGraphSource) ForAllOutgoingChannels(cb func(i *channeldb.ChannelEdgeInfo,
+func (r *mockGraphSource) ForAllOutgoingChannels(cb func(tx kvdb.RTx,
+	i *channeldb.ChannelEdgeInfo,
 	c *channeldb.ChannelEdgePolicy) error) error {
 
 	r.mu.Lock()
@@ -223,7 +225,9 @@ func (r *mockGraphSource) ForAllOutgoingChannels(cb func(i *channeldb.ChannelEdg
 	}
 
 	for _, channel := range chans {
-		cb(channel.Info, channel.Policy1)
+		if err := cb(nil, channel.Info, channel.Policy1); err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -3568,6 +3572,7 @@ out:
 	const newTimeLockDelta = 100
 	var edgesToUpdate []EdgeWithInfo
 	err = ctx.router.ForAllOutgoingChannels(func(
+		_ kvdb.RTx,
 		info *channeldb.ChannelEdgeInfo,
 		edge *channeldb.ChannelEdgePolicy) error {
 
diff --git a/pilot.go b/pilot.go
index 13f500f56..a9ac84777 100644
--- a/pilot.go
+++ b/pilot.go
@@ -282,7 +282,7 @@ func initAutoPilot(svr *server, cfg *lncfg.AutoPilot,
 		ChannelInfo: func(chanPoint wire.OutPoint) (
 			*autopilot.LocalChannel, error) {
 
-			channel, err := svr.chanStateDB.FetchChannel(chanPoint)
+			channel, err := svr.chanStateDB.FetchChannel(nil, chanPoint)
 			if err != nil {
 				return nil, err
 			}
diff --git a/routing/localchans/manager.go b/routing/localchans/manager.go
index 413f86433..b88652e89 100644
--- a/routing/localchans/manager.go
+++ b/routing/localchans/manager.go
@@ -8,6 +8,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/discovery"
 	"github.com/lightningnetwork/lnd/htlcswitch"
+	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing"
 )
@@ -27,12 +28,14 @@ type Manager struct {
 
 	// ForAllOutgoingChannels is required to iterate over all our local
 	// channels.
-	ForAllOutgoingChannels func(cb func(*channeldb.ChannelEdgeInfo,
+	ForAllOutgoingChannels func(cb func(kvdb.RTx,
+		*channeldb.ChannelEdgeInfo,
 		*channeldb.ChannelEdgePolicy) error) error
 
-	// FetchChannel is used to query local channel parameters.
-	FetchChannel func(chanPoint wire.OutPoint) (*channeldb.OpenChannel,
-		error)
+	// FetchChannel is used to query local channel parameters. Optionally an
+	// existing db tx can be supplied.
+	FetchChannel func(tx kvdb.RTx, chanPoint wire.OutPoint) (
+		*channeldb.OpenChannel, error)
 
 	// policyUpdateLock ensures that the database and the link do not fall
 	// out of sync if there are concurrent fee update calls. Without it,
@@ -66,6 +69,7 @@ func (r *Manager) UpdatePolicy(newSchema routing.ChannelPolicy,
 	// If we have a filter then we'll only collected those channels,
 	// otherwise we'll collect them all.
 	err := r.ForAllOutgoingChannels(func(
+		tx kvdb.RTx,
 		info *channeldb.ChannelEdgeInfo,
 		edge *channeldb.ChannelEdgePolicy) error {
 
@@ -197,7 +201,7 @@ func (r *Manager) updateEdge(chanPoint wire.OutPoint,
 func (r *Manager) getHtlcAmtLimits(chanPoint wire.OutPoint) (
 	lnwire.MilliSatoshi, lnwire.MilliSatoshi, error) {
 
-	ch, err := r.FetchChannel(chanPoint)
+	ch, err := r.FetchChannel(nil, chanPoint)
 	if err != nil {
 		return 0, 0, err
 	}
diff --git a/routing/localchans/manager_test.go b/routing/localchans/manager_test.go
index 7ad5128ce..05c97a845 100644
--- a/routing/localchans/manager_test.go
+++ b/routing/localchans/manager_test.go
@@ -3,6 +3,7 @@ package localchans
 import (
 	"testing"
 
+	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
 
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
@@ -88,10 +89,12 @@ func TestManager(t *testing.T) {
 		return nil
 	}
 
-	forAllOutgoingChannels := func(cb func(*channeldb.ChannelEdgeInfo,
+	forAllOutgoingChannels := func(cb func(kvdb.RTx,
+		*channeldb.ChannelEdgeInfo,
 		*channeldb.ChannelEdgePolicy) error) error {
 
 		return cb(
+			nil,
 			&channeldb.ChannelEdgeInfo{
 				Capacity:     chanCap,
 				ChannelPoint: chanPoint,
@@ -100,8 +103,8 @@ func TestManager(t *testing.T) {
 		)
 	}
 
-	fetchChannel := func(chanPoint wire.OutPoint) (*channeldb.OpenChannel,
-		error) {
+	fetchChannel := func(tx kvdb.RTx, chanPoint wire.OutPoint) (
+		*channeldb.OpenChannel, error) {
 
 		constraints := channeldb.ChannelConstraints{
 			MaxPendingAmount: maxPendingAmount,
diff --git a/routing/router.go b/routing/router.go
index e6f4c321e..17b5c4e72 100644
--- a/routing/router.go
+++ b/routing/router.go
@@ -137,7 +137,8 @@ type ChannelGraphSource interface {
 	// ForAllOutgoingChannels is used to iterate over all channels
 	// emanating from the "source" node which is the center of the
 	// star-graph.
-	ForAllOutgoingChannels(cb func(c *channeldb.ChannelEdgeInfo,
+	ForAllOutgoingChannels(cb func(tx kvdb.RTx,
+		c *channeldb.ChannelEdgeInfo,
 		e *channeldb.ChannelEdgePolicy) error) error
 
 	// CurrentBlockHeight returns the block height from POV of the router
@@ -2426,17 +2427,18 @@ func (r *ChannelRouter) ForEachNode(cb func(*channeldb.LightningNode) error) err
 // the router.
 //
 // NOTE: This method is part of the ChannelGraphSource interface.
-func (r *ChannelRouter) ForAllOutgoingChannels(cb func(*channeldb.ChannelEdgeInfo,
-	*channeldb.ChannelEdgePolicy) error) error {
+func (r *ChannelRouter) ForAllOutgoingChannels(cb func(kvdb.RTx,
+	*channeldb.ChannelEdgeInfo, *channeldb.ChannelEdgePolicy) error) error {
 
-	return r.selfNode.ForEachChannel(nil, func(_ kvdb.RTx, c *channeldb.ChannelEdgeInfo,
+	return r.selfNode.ForEachChannel(nil, func(tx kvdb.RTx,
+		c *channeldb.ChannelEdgeInfo,
 		e, _ *channeldb.ChannelEdgePolicy) error {
 
 		if e == nil {
 			return fmt.Errorf("channel from self node has no policy")
 		}
 
-		return cb(c, e)
+		return cb(tx, c, e)
 	})
 }
 
diff --git a/rpcserver.go b/rpcserver.go
index a15235b92..947d28e1c 100644
--- a/rpcserver.go
+++ b/rpcserver.go
@@ -2124,7 +2124,7 @@ func (r *rpcServer) CloseChannel(in *lnrpc.CloseChannelRequest,
 
 	// First, we'll fetch the channel as is, as we'll need to examine it
 	// regardless of if this is a force close or not.
-	channel, err := r.server.chanStateDB.FetchChannel(*chanPoint)
+	channel, err := r.server.chanStateDB.FetchChannel(nil, *chanPoint)
 	if err != nil {
 		return err
 	}
@@ -2402,7 +2402,7 @@ func (r *rpcServer) AbandonChannel(_ context.Context,
 		return nil, err
 	}
 
-	dbChan, err := r.server.chanStateDB.FetchChannel(*chanPoint)
+	dbChan, err := r.server.chanStateDB.FetchChannel(nil, *chanPoint)
 	switch {
 	// If the channel isn't found in the set of open channels, then we can
 	// continue on as it can't be loaded into the link/peer.

From bd07b5f49e9cbe4bbb35481408d683332474d630 Mon Sep 17 00:00:00 2001
From: Joost Jager <joost.jager@gmail.com>
Date: Thu, 19 Aug 2021 17:25:58 +0200
Subject: [PATCH 2/2] routing/localchans: fix nested db tx

This commit fixes a bug where a db tx is opened within another db tx.
---
 docs/release-notes/release-notes-0.14.0.md |  2 ++
 routing/localchans/manager.go              | 10 +++++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/docs/release-notes/release-notes-0.14.0.md b/docs/release-notes/release-notes-0.14.0.md
index b68efef4e..4cfc22bc9 100644
--- a/docs/release-notes/release-notes-0.14.0.md
+++ b/docs/release-notes/release-notes-0.14.0.md
@@ -148,6 +148,8 @@ you.
 * [Fixed context leak in integration tests, and properly handled context
   timeout](https://github.com/lightningnetwork/lnd/pull/5646).
 
+* [Removed nested db tx](https://github.com/lightningnetwork/lnd/pull/5643)
+
 ## Database
 
 * [Ensure single writer for legacy
diff --git a/routing/localchans/manager.go b/routing/localchans/manager.go
index b88652e89..f4d4e5589 100644
--- a/routing/localchans/manager.go
+++ b/routing/localchans/manager.go
@@ -81,7 +81,7 @@ func (r *Manager) UpdatePolicy(newSchema routing.ChannelPolicy,
 		}
 
 		// Apply the new policy to the edge.
-		err := r.updateEdge(info.ChannelPoint, edge, newSchema)
+		err := r.updateEdge(tx, info.ChannelPoint, edge, newSchema)
 		if err != nil {
 			log.Warnf("Cannot update policy for %v: %v\n",
 				info.ChannelPoint, err,
@@ -127,7 +127,7 @@ func (r *Manager) UpdatePolicy(newSchema routing.ChannelPolicy,
 }
 
 // updateEdge updates the given edge with the new schema.
-func (r *Manager) updateEdge(chanPoint wire.OutPoint,
+func (r *Manager) updateEdge(tx kvdb.RTx, chanPoint wire.OutPoint,
 	edge *channeldb.ChannelEdgePolicy,
 	newSchema routing.ChannelPolicy) error {
 
@@ -139,7 +139,7 @@ func (r *Manager) updateEdge(chanPoint wire.OutPoint,
 	edge.TimeLockDelta = uint16(newSchema.TimeLockDelta)
 
 	// Retrieve negotiated channel htlc amt limits.
-	amtMin, amtMax, err := r.getHtlcAmtLimits(chanPoint)
+	amtMin, amtMax, err := r.getHtlcAmtLimits(tx, chanPoint)
 	if err != nil {
 		return nil
 	}
@@ -198,10 +198,10 @@ func (r *Manager) updateEdge(chanPoint wire.OutPoint,
 
 // getHtlcAmtLimits retrieves the negotiated channel min and max htlc amount
 // constraints.
-func (r *Manager) getHtlcAmtLimits(chanPoint wire.OutPoint) (
+func (r *Manager) getHtlcAmtLimits(tx kvdb.RTx, chanPoint wire.OutPoint) (
 	lnwire.MilliSatoshi, lnwire.MilliSatoshi, error) {
 
-	ch, err := r.FetchChannel(nil, chanPoint)
+	ch, err := r.FetchChannel(tx, chanPoint)
 	if err != nil {
 		return 0, 0, err
 	}