fix(sync): do not allow to expand checkpointed tipsets

app/submodule/chain/chain_submodule.go

@@ -21,7 +21,6 @@ import (
 	"github.com/filecoin-project/venus/pkg/vmsupport"
 	v0api "github.com/filecoin-project/venus/venus-shared/api/chain/v0"
 	v1api "github.com/filecoin-project/venus/venus-shared/api/chain/v1"
-	"github.com/filecoin-project/venus/venus-shared/types"
 )
 
 // ChainSubmodule enhances the `Node` with chain capabilities.
@@ -33,8 +32,7 @@ type ChainSubmodule struct { //nolint
 	SystemCall                  vm.SyscallsImpl
 	CirculatingSupplyCalculator *chain.CirculatingSupplyCalculator
 
-	CheckPoint types.TipSetKey
-	Drand      beacon.Schedule
+	Drand beacon.Schedule
 
 	config chainConfig
 
@@ -92,7 +90,6 @@ func NewChainSubmodule(ctx context.Context,
 		Drand:                       drand,
 		config:                      config,
 		Waiter:                      waiter,
-		CheckPoint:                  chainStore.GetCheckPoint(),
 	}
 	err = store.ChainReader.Load(context.TODO())
 	if err != nil {

pkg/chain/store.go

@@ -100,7 +100,7 @@ type Store struct {
 	// head is the tipset at the head of the best known chain.
 	head *types.TipSet
 
-	checkPoint types.TipSetKey
+	checkPoint *types.TipSet
 	// Protects head and genesisCid.
 	mu sync.RWMutex
 
@@ -143,7 +143,6 @@ func NewStore(chainDs repo.Datastore,
 		bsstore:             bsstore,
 		headEvents:          pubsub.New(64),
 
-		checkPoint:     types.EmptyTSK,
 		genesis:        genesisCid,
 		reorgNotifeeCh: make(chan ReorgNotifee),
 		tsCache:        tsCache,
@@ -156,11 +155,22 @@ func NewStore(chainDs repo.Datastore,
 
 	val, err := store.ds.Get(context.TODO(), CheckPoint)
 	if err != nil {
-		store.checkPoint = types.NewTipSetKey(genesisCid)
+		store.checkPoint, err = store.GetTipSet(context.TODO(), types.NewTipSetKey(genesisCid))
+		if err != nil {
+			panic(fmt.Errorf("cannot get genesis tipset: %w", err))
+		}
 	} else {
-		_ = store.checkPoint.UnmarshalCBOR(bytes.NewReader(val)) //nolint:staticcheck
+		var checkPointTSK types.TipSetKey
+		err := checkPointTSK.UnmarshalCBOR(bytes.NewReader(val))
+		if err != nil {
+			panic(fmt.Errorf("cannot unmarshal checkpoint %s: %w", string(val), err))
+		}
+		store.checkPoint, err = store.GetTipSet(context.TODO(), checkPointTSK)
+		if err != nil {
+			panic(fmt.Errorf("cannot get checkpoint tipset: %w", err))
+		}
 	}
-	log.Infof("check point value: %v", store.checkPoint)
+	log.Infof("load check point height: %d, key: %v", store.checkPoint.Height(), store.checkPoint.Key())
 
 	store.reorgCh = store.reorgWorker(context.TODO())
 	return store
@@ -1112,8 +1122,8 @@ func (store *Store) SetCheckpoint(ctx context.Context, ts *types.TipSet) error {
 		return err
 	}
 
-	store.mu.RLock()
-	defer store.mu.RUnlock()
+	store.mu.Lock()
+	defer store.mu.Unlock()
 
 	finality := store.head.Height() - policy.ChainFinality
 	targetChain, currentChain := ts, store.head
@@ -1167,7 +1177,7 @@ func (store *Store) SetCheckpoint(ctx context.Context, ts *types.TipSet) error {
 	if err := store.ds.Put(ctx, CheckPoint, buf.Bytes()); err != nil {
 		return fmt.Errorf("checkpoint failed: failed to record checkpoint in the datastore: %w", err)
 	}
-	store.checkPoint = ts.Key()
+	store.checkPoint = ts
 
 	return nil
 }
@@ -1187,7 +1197,7 @@ func (store *Store) IsAncestorOf(ctx context.Context, a, b *types.TipSet) (bool,
 }
 
 // GetCheckPoint get the check point from store or disk.
-func (store *Store) GetCheckPoint() types.TipSetKey {
+func (store *Store) GetCheckPoint() *types.TipSet {
 	store.mu.RLock()
 	defer store.mu.RUnlock()
 
@@ -1722,7 +1732,7 @@ func (store *Store) exceedsForkLength(ctx context.Context, synced, external *typ
 		}
 
 		// Now check to see if we've walked back to the checkpoint.
-		if synced.Key().Equals(store.checkPoint) {
+		if synced.Key().Equals(store.GetCheckPoint().Key()) {
 			return true, nil
 		}
 

pkg/chainsync/syncer/syncer.go

@@ -60,6 +60,7 @@ var (
 	ErrNewChainTooLong = errors.New("input chain forked from best chain past finality limit")
 	// ErrUnexpectedStoreState indicates that the syncer's chain bsstore is violating expected invariants.
 	ErrUnexpectedStoreState = errors.New("the chain bsstore is in an unexpected state")
+	ErrForkCheckpoint       = fmt.Errorf("fork would require us to diverge from checkpointed block")
 
 	logSyncer = logging.Logger("chainsync.syncer")
 )
@@ -137,8 +138,7 @@ type Syncer struct {
 
 	clock clock.Clock
 
-	bsstore    blockstoreutil.Blockstore
-	checkPoint types.TipSetKey
+	bsstore blockstoreutil.Blockstore
 
 	fork fork.IFork
 
@@ -201,7 +201,7 @@ func (syncer *Syncer) syncOne(ctx context.Context, parent, next *types.TipSet) e
 
 	var err error
 
-	if !parent.Key().Equals(syncer.checkPoint) {
+	if !parent.Key().Equals(syncer.chainStore.GetCheckPoint().Key()) {
 		var wg errgroup.Group
 		for i := 0; i < next.Len(); i++ {
 			blk := next.At(i)
@@ -297,8 +297,25 @@ func (syncer *Syncer) HandleNewTipSet(ctx context.Context, target *syncTypes.Tar
 		return errors.New("do not sync to a target has synced before")
 	}
 
+	if target.Head.Height() == head.Height() {
+		// check if maybeHead is fully contained in headTipSet
+		// meaning we already synced all the blocks that are a part of maybeHead
+		// if that is the case, there is nothing for us to do
+		// we need to exit out early, otherwise checkpoint-fork logic might wrongly reject it
+		fullyContained := true
+		for _, c := range target.Head.Cids() {
+			if !head.Contains(c) {
+				fullyContained = false
+				break
+			}
+		}
+		if fullyContained {
+			return nil
+		}
+	}
+
 	syncer.exchangeClient.AddPeer(target.Sender)
-	tipsets, err := syncer.fetchChainBlocks(ctx, head, target.Head)
+	tipsets, err := syncer.fetchChainBlocks(ctx, head, target.Head, false)
 	if err != nil {
 		return errors.Wrapf(err, "failure fetching or validating headers")
 	}
@@ -346,7 +363,7 @@ func (syncer *Syncer) syncSegement(ctx context.Context, target *syncTypes.Target
 				errProcessChan <- processErr
 				return
 			}
-			if !parent.Key().Equals(syncer.checkPoint) {
+			if !parent.Key().Equals(syncer.chainStore.GetCheckPoint().Key()) {
 				logSyncer.Debugf("set chain head, height:%d, blocks:%d", parent.Height(), parent.Len())
 				if err := syncer.chainStore.RefreshHeaviestTipSet(ctx, parent.Height()); err != nil {
 					errProcessChan <- err
@@ -374,7 +391,7 @@ func (syncer *Syncer) syncSegement(ctx context.Context, target *syncTypes.Target
 // if local db not exist, get block from network(libp2p),
 // if there is a fork, get the common root tipset of knowntip and targettip, and return the block data from root tipset to targettip
 // local(···->A->B) + incoming(C->D->E)  => ···->A->B->C->D->E
-func (syncer *Syncer) fetchChainBlocks(ctx context.Context, knownTip *types.TipSet, targetTip *types.TipSet) ([]*types.TipSet, error) {
+func (syncer *Syncer) fetchChainBlocks(ctx context.Context, knownTip *types.TipSet, targetTip *types.TipSet, ignoreCheckpoint bool) ([]*types.TipSet, error) {
 	chainTipsets := []*types.TipSet{targetTip}
 	flushDB := func(saveTips []*types.TipSet) error {
 		bs := blockstoreutil.NewTemporary()
@@ -448,6 +465,13 @@ loop:
 	if err != nil {
 		return nil, fmt.Errorf("failed to load next local tipset: %w", err)
 	}
+
+	if !ignoreCheckpoint {
+		if chkpt := syncer.chainStore.GetCheckPoint(); chkpt != nil && base.Height() <= chkpt.Height() {
+			return nil, fmt.Errorf("merge point affecting the checkpoing: %w", ErrForkCheckpoint)
+		}
+	}
+
 	if base.IsChildOf(knownParent) {
 		// common case: receiving a block thats potentially part of the same tipset as our best block
 		chain.Reverse(chainTipsets)
@@ -456,7 +480,7 @@ loop:
 
 	logSyncer.Warnf("(fork detected) synced header chain, base: %v(%d), knownTip: %v(%d)", base.Key(), base.Height(),
 		knownTip.Key(), knownTip.Height())
-	fork, err := syncer.syncFork(ctx, base, knownTip)
+	fork, err := syncer.syncFork(ctx, base, knownTip, ignoreCheckpoint)
 	if err != nil {
 		if errors.Is(err, ErrForkTooLong) {
 			// TODO: we're marking this block bad in the same way that we mark invalid blocks bad. Maybe distinguish?
@@ -486,7 +510,15 @@ loop:
 //		D->E-F(targetTip）
 //	A						 => D->E>F
 //		B-C(knownTip)
-func (syncer *Syncer) syncFork(ctx context.Context, incoming *types.TipSet, known *types.TipSet) ([]*types.TipSet, error) {
+func (syncer *Syncer) syncFork(ctx context.Context, incoming *types.TipSet, known *types.TipSet, ignoreCheckpoint bool) ([]*types.TipSet, error) {
+	var chkpt *types.TipSet
+	if !ignoreCheckpoint {
+		chkpt = syncer.chainStore.GetCheckPoint()
+		if known.Equals(chkpt) {
+			return nil, ErrForkCheckpoint
+		}
+	}
+
 	incomingParentsTsk := incoming.Parents()
 	commonParent := false
 	for _, incomingParent := range incomingParentsTsk.Cids() {
@@ -701,7 +733,7 @@ func (syncer *Syncer) SyncCheckpoint(ctx context.Context, tsk types.TipSetKey) e
 		if anc, err := syncer.chainStore.IsAncestorOf(ctx, ts, head); err != nil {
 			return fmt.Errorf("failed to walk the chain when checkpointing: %w", err)
 		} else if !anc {
-			tipsets, err := syncer.fetchChainBlocks(ctx, head, target.Head)
+			tipsets, err := syncer.fetchChainBlocks(ctx, head, target.Head, true)
 			if err != nil {
 				return errors.Wrapf(err, "failure fetching or validating headers")
 			}