eth/downloader, eth/protocols/snap: freeze pivot once state is downloaded (#35155)

core/rawdb/accessors_snapshot.go

@@ -209,48 +209,6 @@ func WriteSnapshotSyncStatus(db ethdb.KeyValueWriter, status []byte) {
 	}
 }
 
-// ReadGenerateTriePartitionDone returns the raw subtree root blob for a
-// partition that has previously completed.
-func ReadGenerateTriePartitionDone(db ethdb.KeyValueReader, partition byte) ([]byte, bool) {
-	data, err := db.Get(generateTriePartitionDoneKey(partition))
-	if err != nil {
-		return nil, false
-	}
-	if len(data) == 0 {
-		return nil, false
-	}
-	switch data[0] {
-	case 0x00:
-		// Partition is done and it is empty.
-		return nil, true
-	case 0x01:
-		// Partition is done and the blob follows.
-		return data[1:], true
-	default:
-		return nil, false
-	}
-}
-
-// WriteGenerateTriePartitionDone records a completed partition.
-func WriteGenerateTriePartitionDone(db ethdb.KeyValueWriter, partition byte, blob []byte) {
-	var value []byte
-	if blob == nil {
-		value = []byte{0x00}
-	} else {
-		value = append([]byte{0x01}, blob...)
-	}
-	if err := db.Put(generateTriePartitionDoneKey(partition), value); err != nil {
-		log.Crit("Failed to store generate-trie done marker", "err", err)
-	}
-}
-
-// DeleteGenerateTriePartitionDone removes a partition's done marker.
-func DeleteGenerateTriePartitionDone(db ethdb.KeyValueWriter, partition byte) {
-	if err := db.Delete(generateTriePartitionDoneKey(partition)); err != nil {
-		log.Crit("Failed to remove generate-trie done marker", "err", err)
-	}
-}
-
 // DeleteSnapshotSyncStatus removes the serialized sync status from the database.
 func DeleteSnapshotSyncStatus(db ethdb.KeyValueWriter) {
 	if err := db.Delete(snapshotSyncStatusKey); err != nil {

core/rawdb/database.go

@@ -563,8 +563,6 @@ func InspectDatabase(db ethdb.Database, keyPrefix, keyStart []byte) error {
 				}
 
 			// Metadata keys
-			case bytes.HasPrefix(key, generateTriePartitionDonePrefix) && len(key) == len(generateTriePartitionDonePrefix)+1:
-				metadata.add(size)
 			case slices.ContainsFunc(knownMetadataKeys, func(x []byte) bool { return bytes.Equal(x, key) }):
 				metadata.add(size)
 

core/rawdb/schema.go

@@ -104,10 +104,6 @@ var (
 	// snapSyncStatusFlagKey flags that status of snap sync.
 	snapSyncStatusFlagKey = []byte("SnapSyncStatus")
 
-	// generateTriePartitionDonePrefix stores the subtree root hash of each
-	// triedb.GenerateTrie partition once it finishes.
-	generateTriePartitionDonePrefix = []byte("gtd") // generateTriePartitionDonePrefix + partition byte -> subtree root hash
-
 	// Data item prefixes (use single byte to avoid mixing data types, avoid `i`, used for indexes).
 	headerPrefix       = []byte("h") // headerPrefix + num (uint64 big endian) + hash -> header
 	headerTDSuffix     = []byte("t") // headerPrefix + num (uint64 big endian) + hash + headerTDSuffix -> td (deprecated)
@@ -469,8 +465,3 @@ func trienodeHistoryIndexBlockKey(addressHash common.Hash, path []byte, blockID
 func transitionStateKey(hash common.Hash) []byte {
 	return append(VerkleTransitionStatePrefix, hash.Bytes()...)
 }
-
-// generateTriePartitionDoneKey = generateTriePartitionDonePrefix + partition (single byte).
-func generateTriePartitionDoneKey(partition byte) []byte {
-	return append(generateTriePartitionDonePrefix, partition)
-}

eth/downloader/beaconsync.go

@@ -297,9 +297,11 @@ func (d *Downloader) fetchHeaders(from uint64) error {
 			return err
 		}
 		// If the pivot became stale (older than 2*64-8 (bit of wiggle room)),
-		// move it ahead to HEAD-64
+		// move it ahead to HEAD-64.
+		//
+		// The state syncer is consulted first before the pivot movement.
 		d.pivotLock.Lock()
-		if d.pivotHeader != nil {
+		if d.pivotHeader != nil && d.snapSyncer.FrozenPivot() == nil {
 			if head.Number.Uint64() > d.pivotHeader.Number.Uint64()+2*uint64(fsMinFullBlocks)-8 {
 				// Retrieve the next pivot header, either from skeleton chain
 				// or the filled chain

eth/downloader/downloader.go

@@ -496,6 +496,18 @@ func (d *Downloader) syncToHead() (err error) {
 	if mode == ethconfig.SnapSync && pivot == nil {
 		pivot = d.blockchain.CurrentBlock()
 	}
+	// If the snap syncer froze its pivot in a previous cycle, resume against
+	// the frozen header instead of a fresh one.
+	if mode == ethconfig.SnapSync && pivot != nil {
+		if frozen := d.snapSyncer.FrozenPivot(); frozen != nil {
+			if rawdb.ReadCanonicalHash(d.stateDB, frozen.Number.Uint64()) == frozen.Hash() {
+				log.Info("Resuming snap sync against frozen pivot", "number", frozen.Number, "hash", frozen.Hash())
+				pivot = frozen
+			} else {
+				log.Warn("Frozen pivot is no longer canonical", "number", frozen.Number, "hash", frozen.Hash())
+			}
+		}
+	}
 	height := latest.Number.Uint64()
 
 	// In beacon mode, use the skeleton chain for the ancestor lookup
@@ -921,7 +933,9 @@ func (d *Downloader) processSnapSyncContent() error {
 	// the results in the meantime.
 	//
 	// Note, there's no issue with memory piling up since after 64 blocks the
-	// pivot will forcefully move so these accumulators will be dropped.
+	// pivot will forcefully move so these accumulators will be dropped. The
+	// exception is snap/2 trie generation, where the pivot is frozen on
+	// purpose and results accumulate until the generation finishes.
 	var (
 		oldPivot *fetchResult   // Locked in pivot block, might change eventually
 		oldTail  []*fetchResult // Downloaded content after the pivot
@@ -978,11 +992,15 @@ func (d *Downloader) processSnapSyncContent() error {
 			return err
 		}
 		if P != nil {
-			// If new pivot block found, cancel old state retrieval and restart
+			// If new pivot block found, cancel old state retrieval and restart.
 			if oldPivot != P {
-				sync.Cancel()
+				// Skip the restart if the running sync already targets the
-				sync = d.syncState(P.Header)
+				// pivot's root (e.g, no pivot block movement yet).
-				go closeOnErr(sync)
+				if sync.pivot.Root != P.Header.Root {
+					sync.Cancel()
+					sync = d.syncState(P.Header)
+					go closeOnErr(sync)
+				}
 				oldPivot = P
 			}
 			// Wait for completion, occasionally checking for pivot staleness

eth/protocols/snap/bal_apply.go

@@ -93,7 +93,7 @@ func (s *syncerV2) isStorageFetched(accountHash, storageHash common.Hash) bool {
 // applyAccessList applies a single block's access list diffs to the flat state
 // in the database. For each account, it applies the post-block values (highest
 // TxIdx entry) for balance, nonce, code, and storage. The storageRoot field is
-// intentionally left stale. It will be recomputed during the trie rebuild.
+// intentionally left stale. It will be recomputed during the trie generation.
 func (s *syncerV2) applyAccessList(b *bal.BlockAccessList, batch ethdb.Batch) error {
 	// Iterate over all accounts in the access list
 	for _, access := range *b {
@@ -113,7 +113,7 @@ func (s *syncerV2) applyAccessList(b *bal.BlockAccessList, batch ethdb.Batch) er
 					rawdb.DeleteStorageSnapshot(batch, accountHash, storageHash)
 				} else {
 					// Store the slot in the same encoding the snapshot and the
-					// trie rebuild use: RLP of the minimal big-endian value
+					// trie generation use: RLP of the minimal big-endian value
 					// (leading zeros trimmed), matching core/state's snapshot
 					// writes.
 					blob, _ := rlp.EncodeToBytes(value.Bytes())
@@ -176,7 +176,7 @@ func (s *syncerV2) applyAccessList(b *bal.BlockAccessList, batch ethdb.Batch) er
 		case isEmpty && !isNew:
 			// Existing account got fully drained (e.g., pre-funded
 			// address that gets deployed to with init code that
-			// self-destructs). Delete the entry so the trie rebuild
+			// self-destructs). Delete the entry so the trie generation
 			// doesn't pick it up as an empty leaf.
 			rawdb.DeleteAccountSnapshot(batch, accountHash)
 		default:

eth/protocols/snap/bal_apply_test.go

@@ -157,7 +157,7 @@ func TestAccessListApplication(t *testing.T) {
 
 	// Verify storage updated. Slots are stored in the canonical snapshot
 	// encoding (RLP of the value with leading zeros trimmed), the same form
-	// the download path writes and the trie rebuild consumes.
+	// the download path writes and the trie generation consumes.
 	storageVal := rawdb.ReadStorageSnapshot(db, accountHash, slotHash)
 	wantStorage, _ := rlp.EncodeToBytes(common.TrimLeftZeroes(common.HexToHash("0x02").Bytes()))
 	if !bytes.Equal(storageVal, wantStorage) {

eth/protocols/snap/handler.go

@@ -84,8 +84,10 @@ type Backend interface {
 // otherwise only the default (snap/1) versions are offered on the wire.
 func MakeProtocols(backend Backend, snapV2 bool) []p2p.Protocol {
 	versions := ProtocolVersions
-	if snapV2 {
+	if !snapV2 {
-		versions = append([]uint{SNAP2}, versions...)
+		// snap/2 is not safe to advertise unconditionally yet, so it is gated
+		// behind a feature flag.
+		versions = []uint{SNAP1}
 	}
 	protocols := make([]p2p.Protocol, len(versions))
 	for i, version := range versions {

eth/protocols/snap/progress_test.go

@@ -186,8 +186,8 @@ func TestSyncProgressV1Discarded(t *testing.T) {
 	syncer := newSyncerV2(db, rawdb.HashScheme)
 	syncer.loadSyncStatus()
 
-	if syncer.previousPivot != nil {
+	if syncer.pivot != nil {
-		t.Fatalf("expected previousPivot nil after discarding old format, got %+v", syncer.previousPivot)
+		t.Fatalf("expected pivot nil after discarding old format, got %+v", syncer.pivot)
 	}
 	if len(syncer.tasks) != accountConcurrency {
 		t.Fatalf("expected fresh task split of %d, got %d", accountConcurrency, len(syncer.tasks))
@@ -258,8 +258,8 @@ func TestSyncProgressCorruptPayload(t *testing.T) {
 	syncer := newSyncerV2(db, rawdb.HashScheme)
 	syncer.loadSyncStatus()
 
-	if syncer.previousPivot != nil {
+	if syncer.pivot != nil {
-		t.Fatalf("expected previousPivot nil after corrupt payload, got %+v", syncer.previousPivot)
+		t.Fatalf("expected pivot nil after corrupt payload, got %+v", syncer.pivot)
 	}
 	if len(syncer.tasks) != accountConcurrency {
 		t.Fatalf("expected fresh task split of %d, got %d", accountConcurrency, len(syncer.tasks))

eth/protocols/snap/protocol.go

@@ -35,11 +35,10 @@ const (
 // devp2p capability negotiation.
 const ProtocolName = "snap"
 
-// ProtocolVersions are the supported versions of the `snap` protocol advertised
+// ProtocolVersions are all the `snap` protocol versions this node implements
-// by default (first is primary). snap/2 is not safe to advertise unconditionally
+// (first is primary). What's actually advertised on the wire is decided by
-// yet, so it is gated behind a feature flag and appended in MakeProtocols rather
+// MakeProtocols, which gates snap/2 behind a feature flag.
-// than listed here.
+var ProtocolVersions = []uint{SNAP2, SNAP1}
-var ProtocolVersions = []uint{SNAP1}
 
 // protocolLengths are the number of implemented messages corresponding to
 // different protocol versions. snap/2 adds GetAccessLists/AccessLists (0x08/0x09).

eth/protocols/snap/syncer.go

@@ -58,6 +58,10 @@ type Syncer interface {
 	OnTrieNodes(peer SyncPeerV2, id uint64, trienodes [][]byte) error
 	OnAccessLists(peer SyncPeerV2, id uint64, lists rlp.RawList[rlp.RawValue]) error
 
+	// FrozenPivot returns the pivot header the syncer is bound to, or nil if
+	// the pivot may still be chosen and moved freely.
+	FrozenPivot() *types.Header
+
 	// Version is the snap protocol version this syncer implements.
 	Version() uint
 }
@@ -122,6 +126,11 @@ func (syncerV1Adapter) OnAccessLists(SyncPeerV2, uint64, rlp.RawList[rlp.RawValu
 // Version is SNAP1
 func (syncerV1Adapter) Version() uint { return SNAP1 }
 
+// FrozenPivot is always nil for snap/1: the sync target must keep tracking
+// the chain head, ensuring the state is available in the network, so the
+// pivot is never frozen.
+func (syncerV1Adapter) FrozenPivot() *types.Header { return nil }
+
 // syncerV2Adapter adapts the snap/2 *syncerV2 to Syncer. Its peer-facing methods
 // already take SyncPeerV2 and its Sync already takes a header, so only Progress
 // (different return type) and OnTrieNodes (absent) need wrapping.

eth/protocols/snap/syncv2.go

@@ -26,6 +26,7 @@ import (
 	"math/rand"
 	"sort"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -261,13 +262,34 @@ type storageTaskV2 struct {
 	done bool              // Flag whether the task can be removed
 }
 
+// syncPhase tracks how far a snap/2 sync has progressed for the journaled
+// pivot. The phases are strictly ordered: each one implies all previous
+// ones have finished.
+type syncPhase uint8
+
+const (
+	// phaseDownload covers the flat state (account, storage, bytecode)
+	// download. The requests target the pivot root, which remote peers
+	// only serve while it is recent, so the pivot must keep tracking the
+	// chain head (see FrozenPivot).
+	phaseDownload syncPhase = iota
+
+	// phaseGenerate covers the local trie generation after the download
+	// has completed. It targets the exact pivot root it was started with,
+	// so pivot updates are refused from here on.
+	phaseGenerate
+
+	// phaseComplete means the sync ran to completion for the pivot.
+	phaseComplete
+)
+
 // syncProgressV2 is a database entry to allow suspending and resuming a snapshot state
 // sync. Opposed to full and fast sync, there is no way to restart a suspended
 // snap sync without prior knowledge of the suspension point.
 type syncProgressV2 struct {
-	Pivot    *types.Header    // Pivot header being synced (for pivot move and reorg detection)
+	Pivot *types.Header    // Pivot header being synced (for pivot move and reorg detection)
-	Tasks    []*accountTaskV2 // The suspended account tasks (contract tasks within)
+	Tasks []*accountTaskV2 // The suspended account tasks (contract tasks within)
-	Complete bool             // True once sync ran to completion for Pivot
+	Phase syncPhase        // Phase is how far the sync has progressed for Pivot
 
 	// Status report during syncing phase
 	AccountSynced  uint64             // Number of accounts downloaded
@@ -313,7 +335,7 @@ type SyncPeerV2 interface {
 // syncerV2 is an Ethereum account and storage trie syncer based on the snap
 // protocol. It downloads all accounts, storage slots, and bytecodes from
 // remote peers as flat state, applies BAL diffs on pivot moves,
-// and triggers a final trie rebuild once flat state is consistent.
+// and triggers a final trie generation once flat state is consistent.
 //
 // Every network request has a variety of failure events:
 //   - The peer disconnects after task assignment, failing to send the request
@@ -322,14 +344,12 @@ type SyncPeerV2 interface {
 //   - The peer delivers a stale response after a previous timeout
 //   - The peer delivers a refusal to serve the requested state
 type syncerV2 struct {
-	db     ethdb.Database // Database to store the trie nodes into (and dedup)
+	db     ethdb.Database   // Database to store the trie nodes into (and dedup)
-	scheme string         // Node scheme used in node database
+	scheme string           // Node scheme used in node database
-
+	pivot  *types.Header    // Current pivot header being synced (lock needed)
-	pivot         *types.Header    // Current pivot header being synced (lock needed)
+	phase  atomic.Uint32    // Current syncPhase; atomic so phase transitions are visible across goroutines
-	previousPivot *types.Header    // Pivot from previous sync run (for pivot move detection)
+	tasks  []*accountTaskV2 // Current account task set being synced
-	complete      bool             // Whether the persisted progress was a completed sync
+	update chan struct{}    // Notification channel for possible sync progression
-	tasks         []*accountTaskV2 // Current account task set being synced
-	update        chan struct{}    // Notification channel for possible sync progression
 
 	peers    map[string]SyncPeerV2 // Currently active peers to download from
 	peerJoin *event.Feed           // Event feed to react to peers joining
@@ -370,7 +390,7 @@ type syncerV2 struct {
 // newSyncerV2 creates a new snapshot syncer to download the Ethereum state over the
 // snap protocol.
 func newSyncerV2(db ethdb.Database, scheme string) *syncerV2 {
-	return &syncerV2{
+	s := &syncerV2{
 		db:     db,
 		scheme: scheme,
 
@@ -393,6 +413,24 @@ func newSyncerV2(db ethdb.Database, scheme string) *syncerV2 {
 
 		extProgress: new(syncProgressV2),
 	}
+	if raw := rawdb.ReadSnapshotSyncStatus(db); len(raw) > 0 && raw[0] == syncProgressVersion {
+		var progress syncProgressV2
+		if err := json.Unmarshal(raw[1:], &progress); err == nil {
+			s.pivot = progress.Pivot
+			s.setPhase(progress.Phase)
+		}
+	}
+	return s
+}
+
+// getPhase returns the current sync phase.
+func (s *syncerV2) getPhase() syncPhase {
+	return syncPhase(s.phase.Load())
+}
+
+// setPhase moves the sync to the given phase.
+func (s *syncerV2) setPhase(phase syncPhase) {
+	s.phase.Store(uint32(phase))
 }
 
 // Register injects a new data source into the syncer's peerset.
@@ -452,19 +490,17 @@ func (s *syncerV2) Unregister(id string) error {
 // Sync starts (or resumes a previous) sync cycle to iterate over a state trie
 // with the given pivot header and reconstruct the nodes based on the snapshot
 // leaves.
-func (s *syncerV2) Sync(pivot *types.Header, cancel chan struct{}) error {
+func (s *syncerV2) Sync(target *types.Header, cancel chan struct{}) error {
-	if pivot == nil {
+	if target == nil {
 		return errors.New("snap sync: pivot header is nil")
 	}
 	s.lock.Lock()
-	s.pivot = pivot
-	s.previousPivot = nil // loadSyncStatus overwrites when resuming from persisted progress
 	s.statelessPeers = make(map[string]struct{})
 	s.lock.Unlock()
 	if s.startTime.IsZero() {
 		s.startTime = time.Now()
 	}
-	root := pivot.Root
+	root := target.Root
 
 	// Retrieve the previous sync status from DB. If there's no persisted
 	// status, sync is either fresh or already complete.
@@ -473,20 +509,24 @@ func (s *syncerV2) Sync(pivot *types.Header, cancel chan struct{}) error {
 	// isPivotChanged is true when we have prior progress against a different
 	// pivot. That means we need to roll forward via catchUp, or wipe and
 	// restart if the prior pivot was reorged out.
-	isPivotChanged := s.previousPivot != nil && s.previousPivot.Hash() != s.pivot.Hash()
+	s.lock.RLock()
+	prevPivot := s.pivot
+	s.lock.RUnlock()
+	isPivotChanged := prevPivot != nil && prevPivot.Hash() != target.Hash()
 
 	// Skip if we've already finished syncing this pivot.
-	if !isPivotChanged && s.complete {
+	if !isPivotChanged && s.getPhase() == phaseComplete {
 		log.Info("Snap sync already complete for this pivot", "root", root)
 		return nil
 	}
 
-	// We're committing to running this sync. Clear the complete flag so a
+	// We're committing to running this sync. Demote a completed phase so a
-	// mid-run save (on cancel or error) doesn't persist a stale Complete=true
+	// mid-run save (on cancel or error) doesn't persist a stale complete
-	// status from a prior pivot.
+	// status from a prior pivot. The download remains done, only the trie
-	s.lock.Lock()
+	// generation must be redone against the new pivot.
-	s.complete = false
+	if s.getPhase() == phaseComplete {
-	s.lock.Unlock()
+		s.setPhase(phaseGenerate)
+	}
 
 	defer func() {
 		// Whether sync completed or not, disregard any future packets
@@ -515,24 +555,25 @@ func (s *syncerV2) Sync(pivot *types.Header, cancel chan struct{}) error {
 	// progress is still usable. If yes, roll forward via BAL catch-up. If not,
 	// wipe everything and restart fresh.
 	if isPivotChanged {
-		if isPivotReorged(s.db, s.previousPivot, s.pivot) {
+		if isPivotReorged(s.db, prevPivot, target) {
-			log.Warn("Persisted progress unusable, restarting snap sync from scratch",
+			log.Warn("Restarting snap sync from scratch", "oldnumber", prevPivot.Number, "oldHash", prevPivot.Hash())
-				"number", s.previousPivot.Number, "oldHash", s.previousPivot.Hash())
 			s.resetSyncState()
-		} else if err := s.catchUp(cancel); err != nil {
+		} else {
-			return err
+			// A canonical pivot move past a frozen pivot should be impossible:
+			// the downloader both refuses moves (FrozenPivot) and resumes new
+			// cycles against the frozen header itself. Reaching this branch
+			// frozen indicates a bug on the downloader side; roll the flat
+			// state forward defensively and regenerate.
+			if s.getPhase() >= phaseGenerate {
+				log.Warn("Frozen pivot moved unexpectedly, rolling forward", "frozen", prevPivot.Number, "new", target.Number)
+			}
+			if err := s.catchUp(target, cancel); err != nil {
+				return err
+			}
 		}
 	}
-
-	// Pin previousPivot to the current pivot before downloadState runs.
-	// This is what saveSyncStatus persists. If the download is interrupted
-	// and the next Sync gets a different pivot, this is how isPivotReorged
-	// recognizes the partial flat state belongs to the old pivot. Without
-	// it, isPivotReorged sees nil, skips the reorg branch, and downloadState
-	// would resume from the persisted task markers but mix the old pivot's
-	// already-downloaded accounts with the new pivot's data.
 	s.lock.Lock()
-	s.previousPivot = s.pivot
+	s.pivot = target
 	s.lock.Unlock()
 
 	log.Info("Starting state download", "root", root)
@@ -541,21 +582,47 @@ func (s *syncerV2) Sync(pivot *types.Header, cancel chan struct{}) error {
 	}
 	log.Info("State download complete", "root", root)
 
+	// Entering the generation phase makes the downloader stop moving the
+	// pivot (see FrozenPivot) until the pivot block is committed. The phase
+	// is persisted right away so the freeze also holds across a restart,
+	// before the generation has had a chance to finish.
+	if s.getPhase() < phaseGenerate {
+		s.setPhase(phaseGenerate)
+		s.saveSyncStatus()
+	}
+
 	log.Info("Starting trie generation", "root", root)
+	batch := s.db.NewBatch()
+	s.resetTrienodes(batch)
+	if err := batch.Write(); err != nil {
+		return err
+	}
 	if _, err := triedb.GenerateTrie(s.db, s.scheme, root, cancel); err != nil {
 		return err
 	}
 	log.Info("Trie generation complete", "root", root)
 
-	// Mark sync complete. The deferred saveSyncStatus persists this with
+	// Mark sync complete. The deferred saveSyncStatus persists this so a
-	// Complete=true so a follow-up Sync call for the same pivot can skip
+	// follow-up Sync call for the same pivot can skip the work entirely.
-	// the work entirely.
+	s.setPhase(phaseComplete)
-	s.lock.Lock()
-	s.complete = true
-	s.lock.Unlock()
 	return nil
 }
 
+// FrozenPivot returns the pivot header the sync is bound to, or nil while
+// the pivot may still move freely. The pivot freezes once the state
+// download completes. The remaining work (trie generation) and the pivot
+// commit is purely local and targets the exact pivot root the download
+// finished with, so from that point on the downloader must neither move the
+// pivot nor start a new cycle against a different one.
+func (s *syncerV2) FrozenPivot() *types.Header {
+	if s.getPhase() < phaseGenerate {
+		return nil
+	}
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+	return s.pivot
+}
+
 // download runs the bulk flat-state download. It fetches
 // account ranges, storage slots, and bytecodes, writing flat state to disk.
 func (s *syncerV2) downloadState(cancel chan struct{}) error {
@@ -660,10 +727,10 @@ func isPivotReorged(db ethdb.Database, prev, curr *types.Header) bool {
 // catchUp runs the BAL catch-up. When the pivot has moved, it fetches BALs
 // for the gap blocks, verifies them against block headers, and applies the
 // diffs to roll flat state forward.
-func (s *syncerV2) catchUp(cancel chan struct{}) error {
+func (s *syncerV2) catchUp(target *types.Header, cancel chan struct{}) error {
 	s.lock.RLock()
-	from := s.previousPivot.Number.Uint64() + 1
+	from := s.pivot.Number.Uint64() + 1
-	to := s.pivot.Number.Uint64()
+	to := target.Number.Uint64()
 	s.lock.RUnlock()
 	log.Info("Starting BAL catch-up", "from", from, "to", to, "blocks", to-from+1)
 
@@ -720,7 +787,7 @@ func (s *syncerV2) catchUp(cancel chan struct{}) error {
 		// Persist incremental progress so a crash mid-catchUp can resume
 		// from the next unapplied block.
 		s.lock.Lock()
-		s.previousPivot = headers[hash]
+		s.pivot = headers[hash]
 		s.lock.Unlock()
 		s.saveSyncStatusWithDB(batch)
 
@@ -952,8 +1019,8 @@ func (s *syncerV2) loadSyncStatus() {
 				}
 				task.StorageCompleted = nil
 			}
-			s.previousPivot = progress.Pivot
+			s.pivot = progress.Pivot
-			s.complete = progress.Complete
+			s.setPhase(progress.Phase)
 			s.accountSynced = progress.AccountSynced
 			s.accountBytes = progress.AccountBytes
 			s.bytecodeSynced = progress.BytecodeSynced
@@ -1005,6 +1072,16 @@ func deleteRange(batch ethdb.Batch, prefix []byte) {
 	}
 }
 
+// resetTrienodes wipes all persisted trienodes if the path scheme is used.
+// It's a defensive operation, ensuring all the leftover trie nodes are cleared
+// before the new generation cycle.
+func (s *syncerV2) resetTrienodes(batch ethdb.Batch) {
+	if s.scheme == rawdb.PathScheme {
+		deleteRange(batch, rawdb.TrieNodeAccountPrefix)
+		deleteRange(batch, rawdb.TrieNodeStoragePrefix)
+	}
+}
+
 // resetSyncState wipes all persisted snap-sync data (sync status, account
 // and storage snapshots) and re-initializes in-memory state with a fresh
 // chunking of the account hash range.
@@ -1013,14 +1090,15 @@ func (s *syncerV2) resetSyncState() {
 	rawdb.DeleteSnapshotSyncStatus(batch)
 	deleteRange(batch, rawdb.SnapshotAccountPrefix)
 	deleteRange(batch, rawdb.SnapshotStoragePrefix)
+	s.resetTrienodes(batch)
 	batch.Write()
 
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
 	s.tasks = nil
-	s.previousPivot = nil
+	s.pivot = nil
-	s.complete = false
+	s.setPhase(phaseDownload)
 	s.accountSynced, s.accountBytes = 0, 0
 	s.bytecodeSynced, s.bytecodeBytes = 0, 0
 	s.storageSynced, s.storageBytes = 0, 0
@@ -1069,9 +1147,9 @@ func (s *syncerV2) saveSyncStatusWithDB(db ethdb.KeyValueWriter) {
 	}
 	// Store the actual progress markers.
 	progress := &syncProgressV2{
-		Pivot:          s.previousPivot,
+		Pivot:          s.pivot,
 		Tasks:          s.tasks,
-		Complete:       s.complete,
+		Phase:          s.getPhase(),
 		AccountSynced:  s.accountSynced,
 		AccountBytes:   s.accountBytes,
 		BytecodeSynced: s.bytecodeSynced,
@@ -2028,7 +2106,7 @@ func (s *syncerV2) forwardAccountTask(task *accountTaskV2) {
 
 	// Persist the received account segments. These flat state maybe
 	// outdated during the sync, but it can be fixed later during the
-	// trie rebuild.
+	// trie generation.
 	oldAccountBytes := s.accountBytes
 
 	batch := ethdb.HookedBatch{

eth/protocols/snap/syncv2_test.go

@@ -547,6 +547,65 @@ func testSyncV2(t *testing.T, scheme string) {
 	verifyAdoptedSyncedState(scheme, syncer.db, sourceAccountTrie.Hash(), elems, t)
 }
 
+// TestSyncV2FrozenPivot checks the pivot freeze signal around the sync
+// lifecycle. The pivot is unfrozen while flat state is downloading, frozen
+// once the download completes, stays frozen after the sync returns so the
+// downloader resumes against it until the pivot block is committed, and
+// unfreezes again after a state reset.
+func TestSyncV2FrozenPivot(t *testing.T) {
+	t.Parallel()
+	testSyncV2FrozenPivot(t, rawdb.HashScheme)
+	testSyncV2FrozenPivot(t, rawdb.PathScheme)
+}
+
+func testSyncV2FrozenPivot(t *testing.T, scheme string) {
+	var (
+		once   sync.Once
+		cancel = make(chan struct{})
+		term   = func() { once.Do(func() { close(cancel) }) }
+	)
+	nodeScheme, sourceAccountTrie, elems := makeAccountTrieNoStorage(100, scheme)
+
+	source := newTestPeerV2("source", t, term)
+	source.accountTrie = sourceAccountTrie.Copy()
+	source.accountValues = elems
+
+	syncer := setupSyncerV2(nodeScheme, source)
+	pivot := mkPivot(0, sourceAccountTrie.Hash())
+
+	// The handler runs while account ranges are still being served, so it
+	// can observe the signal mid download.
+	source.accountRequestV2Handler = func(p *testPeerV2, requestId uint64, root common.Hash, origin common.Hash, limit common.Hash, cap int) error {
+		if syncer.FrozenPivot() != nil {
+			t.Error("pivot frozen during flat state download")
+		}
+		return defaultAccountRequestHandlerV2(p, requestId, root, origin, limit, cap)
+	}
+	if syncer.FrozenPivot() != nil {
+		t.Fatal("pivot frozen before sync started")
+	}
+	if err := syncer.Sync(pivot, cancel); err != nil {
+		t.Fatalf("sync failed: %v", err)
+	}
+	if frozen := syncer.FrozenPivot(); frozen == nil || frozen.Hash() != pivot.Hash() {
+		t.Fatal("pivot not frozen at the synced header after download completed")
+	}
+	// A restart must not lose the freeze: a fresh syncer instance on the same
+	// database derives it from the persisted journal, before any Sync call.
+	restarted := newSyncerV2(syncer.db, nodeScheme)
+	if frozen := restarted.FrozenPivot(); frozen == nil || frozen.Hash() != pivot.Hash() {
+		t.Fatal("pivot freeze lost after restart")
+	}
+	syncer.resetSyncState()
+	if syncer.FrozenPivot() != nil {
+		t.Fatal("pivot still frozen after state reset")
+	}
+	// The reset deletes the journal, so a restarted instance is unfrozen too.
+	if restarted := newSyncerV2(syncer.db, nodeScheme); restarted.FrozenPivot() != nil {
+		t.Fatal("pivot still frozen after restart following a state reset")
+	}
+}
+
 // verifyAdoptedSyncedState exercises the snap/2 completion contract end-to-end:
 // after a real sync, opening a fresh triedb and calling AdoptSyncedState must
 // (a) succeed and (b) leave flat-state reads serving immediately, with no
@@ -1326,9 +1385,9 @@ func TestIsPivotReorged(t *testing.T) {
 // canonical header at block 100 has a different hash. Sync is then called with
 // a new pivot at the same height.
 //
-// If isPivotReorged works, loadSyncStatus restores previousPivot, the check
+// If isPivotReorged works, loadSyncStatus restores the persisted pivot, the
-// flags it as reorged, resetSyncState clears previousPivot, catchUp is
+// check flags it as reorged, resetSyncState clears it, catchUp is skipped,
-// skipped, and the fresh download proceeds to completion.
+// and the fresh download proceeds to completion.
 //
 // If detection doesn't fire, the pivot-move check would call catchUp with
 // from = 101 and to = 100 — the inverted-range guard surfaces that as an
@@ -1347,10 +1406,8 @@ func TestSyncDetectsPivotReorged(t *testing.T) {
 	// and non-zero counter so the reset path has something to clean up.
 	orphanPivot := mkPivot(100, common.HexToHash("0xdead"))
 	seed := newSyncerV2(db, nodeScheme)
-	// previousPivot reflects where flat state matches and it is what
+	// pivot reflects where flat state matches and it is what saveSyncStatus
-	// saveSyncStatus persists. Set it to simulate a prior sync reaching
+	// persists. Set it to simulate a prior sync reaching orphanPivot.
-	// orphanPivot.
-	seed.previousPivot = orphanPivot
 	seed.pivot = orphanPivot
 	seed.accountSynced = 42
 	seed.tasks = []*accountTaskV2{{
@@ -1391,14 +1448,14 @@ func TestSyncDetectsPivotReorged(t *testing.T) {
 	if err := syncer.Sync(newPivot, cancel); err != nil {
 		t.Fatalf("sync failed (reorg detection likely broken): %v", err)
 	}
-	// After successful completion, status should be marked Complete=true
+	// After successful completion, status should reach the complete phase
 	// against the new (canonical) pivot.
 	loader := newSyncerV2(db, nodeScheme)
 	loader.loadSyncStatus()
-	if !loader.complete {
+	if loader.getPhase() != phaseComplete {
-		t.Fatal("sync status should be marked Complete=true after successful completion")
+		t.Fatal("sync status should reach the complete phase after successful completion")
 	}
-	if loader.previousPivot == nil || loader.previousPivot.Hash() != newPivot.Hash() {
+	if loader.pivot == nil || loader.pivot.Hash() != newPivot.Hash() {
 		t.Fatalf("expected persisted pivot to match new pivot")
 	}
 	if data := rawdb.ReadAccountSnapshot(db, orphanAccountHash); len(data) != 0 {
@@ -1445,9 +1502,8 @@ func testInterruptedDownloadRecovery(t *testing.T, scheme string) {
 	syncer1.Register(src1)
 	src1.remote = syncer1
 	pivot := mkPivot(0, root)
-	syncer1.pivot = pivot
-	syncer1.previousPivot = pivot // Sync sets this before downloadState
 	syncer1.loadSyncStatus()
+	syncer1.pivot = pivot // Sync pins this before downloadState
 	syncer1.downloadState(cancel1)
 
 	// Save progress
@@ -1483,9 +1539,8 @@ func testInterruptedDownloadRecovery(t *testing.T, scheme string) {
 	syncer2.Register(src2)
 	src2.remote = syncer2
 	pivot2 := mkPivot(0, root)
-	syncer2.pivot = pivot2
-	syncer2.previousPivot = pivot2 // Sync sets this before downloadState
 	syncer2.loadSyncStatus()
+	syncer2.pivot = pivot2 // Sync pins this before downloadState
 	if err := syncer2.downloadState(cancel2); err != nil {
 		t.Fatalf("resumed download failed: %v", err)
 	}
@@ -1499,10 +1554,10 @@ func testInterruptedDownloadRecovery(t *testing.T, scheme string) {
 }
 
 // TestSyncPersistsPivotDuringDownload verifies that after a fresh Sync is
-// interrupted mid-download, the persisted previousPivot equals the current
+// interrupted mid-download, the persisted pivot equals the current pivot
-// pivot (not nil). Without this, a follow-up Sync at a different pivot
+// (not nil). Without this, a follow-up Sync at a different pivot would not
-// would not see that the partial flat state belongs to the old pivot, and
+// see that the partial flat state belongs to the old pivot, and would mix
-// would mix old-pivot accounts with new-pivot data.
+// old-pivot accounts with new-pivot data.
 func TestSyncPersistsPivotDuringDownload(t *testing.T) {
 	t.Parallel()
 	nodeScheme, sourceAccountTrie, elems := makeAccountTrieNoStorage(100, rawdb.HashScheme)
@@ -1532,15 +1587,15 @@ func TestSyncPersistsPivotDuringDownload(t *testing.T) {
 	// Sync should be interrupted by the cancel after a couple of responses.
 	_ = syncer.Sync(pivot, cancel)
 
-	// Persisted previousPivot must equal the pivot, so a follow-up Sync at a
+	// Persisted pivot must equal the pivot, so a follow-up Sync at a different
-	// different pivot can recognize the partial flat state belongs to this one.
+	// pivot can recognize the partial flat state belongs to this one.
 	loader := newSyncerV2(db, nodeScheme)
 	loader.loadSyncStatus()
-	if loader.previousPivot == nil {
+	if loader.pivot == nil {
-		t.Fatal("expected persisted previousPivot to be set after interrupted download, got nil")
+		t.Fatal("expected persisted pivot to be set after interrupted download, got nil")
 	}
-	if loader.previousPivot.Hash() != pivot.Hash() {
+	if loader.pivot.Hash() != pivot.Hash() {
-		t.Errorf("persisted previousPivot mismatch: got %v, want %v", loader.previousPivot.Hash(), pivot.Hash())
+		t.Errorf("persisted pivot mismatch: got %v, want %v", loader.pivot.Hash(), pivot.Hash())
 	}
 }
 
@@ -1702,7 +1757,7 @@ func testPivotMovement(t *testing.T, scheme string, pivotMoves int) {
 }
 
 // TestCatchUpPersistsIncrementally verifies that catchUp updates and persists
-// previousPivot after each successfully applied BAL. If a later block in the
+// the pivot after each successfully applied BAL. If a later block in the
 // gap fails to apply, the persisted state reflects the last successful block,
 // so a follow-up Sync can resume from there rather than reapplying everything.
 func TestCatchUpPersistsIncrementally(t *testing.T) {
@@ -1776,7 +1831,7 @@ func testCatchUpPersistsIncrementally(t *testing.T, scheme string) {
 		blocks[i] = balBlock{header: header, bal: buf.Bytes()}
 	}
 
-	// First sync: complete sync to A so persisted state has previousPivot=A,
+	// First sync: complete sync to A so persisted state has pivot=A,
 	// flat state covers all accounts.
 	{
 		var (
@@ -1826,22 +1881,22 @@ func testCatchUpPersistsIncrementally(t *testing.T, scheme string) {
 		t.Fatal("expected Sync to fail when applyAccessList hits corrupt flat state")
 	}
 
-	// Persisted previousPivot should now reflect the last successfully applied
+	// Persisted pivot should now reflect the last successfully applied
 	// block (A+2). Without per-iteration saves, it would still be at A.
 	loader := newSyncerV2(db, nodeScheme)
 	loader.loadSyncStatus()
-	if loader.previousPivot == nil {
+	if loader.pivot == nil {
-		t.Fatal("expected persisted previousPivot to be set after partial catchUp")
+		t.Fatal("expected persisted pivot to be set after partial catchUp")
 	}
 	wantHash := blocks[1].header.Hash()
-	if loader.previousPivot.Hash() != wantHash {
+	if loader.pivot.Hash() != wantHash {
-		t.Errorf("persisted previousPivot mismatch after partial catchUp: got %v, want %v (block A+2)",
+		t.Errorf("persisted pivot mismatch after partial catchUp: got %v, want %v (block A+2)",
-			loader.previousPivot.Hash(), wantHash)
+			loader.pivot.Hash(), wantHash)
 	}
 }
 
 // TestSyncStatusMarkedCompleteAfterCompletion verifies that after a full sync
-// completes, the persisted sync status has Complete=true. This lets a
+// completes, the persisted sync status reaches the complete phase. This lets a
 // subsequent Sync call distinguish "already done" from "fresh node" and skip.
 func TestSyncStatusMarkedCompleteAfterCompletion(t *testing.T) {
 	t.Parallel()
@@ -1870,13 +1925,13 @@ func testSyncStatusMarkedCompleteAfterCompletion(t *testing.T, scheme string) {
 	}
 
 	// After successful sync, persisted status should be present with
-	// Complete=true and the pivot we synced to.
+	// the complete phase and the pivot we synced to.
 	loader := newSyncerV2(syncer.db, nodeScheme)
 	loader.loadSyncStatus()
-	if !loader.complete {
+	if loader.getPhase() != phaseComplete {
-		t.Fatal("expected persisted status to have Complete=true after successful sync")
+		t.Fatal("expected persisted status to reach the complete phase after successful sync")
 	}
-	if loader.previousPivot == nil || loader.previousPivot.Hash() != pivot.Hash() {
+	if loader.pivot == nil || loader.pivot.Hash() != pivot.Hash() {
 		t.Fatalf("expected persisted pivot to match synced pivot")
 	}
 }
@@ -1906,7 +1961,7 @@ func TestSyncSkipsIfAlreadyComplete(t *testing.T) {
 		t.Fatalf("first sync failed: %v", err)
 	}
 
-	// Wipe the flat state. The persisted status (with Complete=true) stays.
+	// Wipe the flat state. The persisted status (in the complete phase) stays.
 	if err := syncer.db.DeleteRange(rawdb.SnapshotAccountPrefix, []byte{rawdb.SnapshotAccountPrefix[0] + 1}); err != nil {
 		t.Fatalf("failed to wipe account snapshot: %v", err)
 	}
@@ -1922,17 +1977,17 @@ func TestSyncSkipsIfAlreadyComplete(t *testing.T) {
 	}
 }
 
-// TestInterruptedRebuildRecovery verifies that if sync is interrupted after
+// TestInterruptedGenerationRecovery verifies that if sync is interrupted after
-// download completes but before trie rebuild finishes, the next Sync() call
+// download completes but before trie generation finishes, the next Sync() call
-// re-runs the download (which completes immediately) and rebuild.
+// re-runs the download (which completes immediately) and generation.
-func TestInterruptedRebuildRecovery(t *testing.T) {
+func TestInterruptedGenerationRecovery(t *testing.T) {
 	t.Parallel()
 
 	nodeScheme, sourceAccountTrie, elems := makeAccountTrieNoStorage(100, rawdb.HashScheme)
 	root := sourceAccountTrie.Hash()
 
 	// First run: complete download, save status, simulate interruption
-	// before rebuild by calling downloadState() directly
+	// before generation by calling downloadState() directly
 	var (
 		once1   sync.Once
 		cancel1 = make(chan struct{})
@@ -1946,9 +2001,8 @@ func TestInterruptedRebuildRecovery(t *testing.T) {
 	syncer1.Register(src1)
 	src1.remote = syncer1
 	pivot := mkPivot(0, root)
-	syncer1.pivot = pivot
-	syncer1.previousPivot = pivot // Sync sets this before downloadState
 	syncer1.loadSyncStatus()
+	syncer1.pivot = pivot // Sync pins this before downloadState
 
 	if err := syncer1.downloadState(cancel1); err != nil {
 		t.Fatalf("download failed: %v", err)
@@ -1960,11 +2014,11 @@ func TestInterruptedRebuildRecovery(t *testing.T) {
 	syncer1.cleanAccountTasks()
 	syncer1.saveSyncStatus()
 
-	// Status should exist (rebuild hasn't run yet)
+	// Status should exist (generation hasn't run yet)
 	if rawdb.ReadSnapshotSyncStatus(db) == nil {
 		t.Fatal("sync status should exist after download")
 	}
-	// Second run: full Sync should detect tasks are done, run rebuild
+	// Second run: full Sync should detect tasks are done, run generation
 	var (
 		once2   sync.Once
 		cancel2 = make(chan struct{})
@@ -1980,11 +2034,16 @@ func TestInterruptedRebuildRecovery(t *testing.T) {
 	if err := syncer2.Sync(mkPivot(0, root), cancel2); err != nil {
 		t.Fatalf("resumed sync failed: %v", err)
 	}
-	// After rebuild completes, status should be marked Complete=true.
+	// The resumed run re-arms the pivot freeze once its no-op download
+	// completes, the downloader relies on it until the pivot block commits.
+	if syncer2.FrozenPivot() == nil {
+		t.Fatal("pivot not frozen after resumed sync")
+	}
+	// After generation completes, status should reach the complete phase.
 	loader := newSyncerV2(db, nodeScheme)
 	loader.loadSyncStatus()
-	if !loader.complete {
+	if loader.getPhase() != phaseComplete {
-		t.Fatal("sync status should be marked Complete=true after rebuild completes")
+		t.Fatal("sync status should reach the complete phase after generation completes")
 	}
 }
 
@@ -2462,7 +2521,7 @@ func TestCatchUpRetriesOnBadBAL(t *testing.T) {
 
 // makeStorageTrieFromSlots builds a storage trie for owner from raw slot
 // key->value pairs, using the exact on-disk encoding the flat snapshot and the
-// trie rebuild expect: each leaf is keyed by keccak256(slotKey) and its value is
+// trie generation expect: each leaf is keyed by keccak256(slotKey) and its value is
 // rlp(TrimLeftZeroes(value)). Zero-valued slots are skipped (an unset slot has
 // no leaf). It returns the storage root, the dirty node set, and the sorted
 // snapshot leaves (which a test peer serves verbatim).
@@ -2529,12 +2588,12 @@ func makeStateWithStorageContract(scheme string, plain []*kv, contractAddr commo
 // slot, an overwrite of an existing slot, a write of zero (deletion), and a
 // multi-tx write where the post-block value wins.
 //
-// It fully syncs pivot A (flat-state download + trie rebuild), then moves the
+// It fully syncs pivot A (flat-state download + trie generation), then moves the
 // pivot to A+1. The move triggers catchUp, which fetches the A+1 BAL, applies
-// the storage diffs to the flat state, and rebuilds the trie. The rebuild
+// the storage diffs to the flat state, and generates the trie. The generation
 // verifies the recomputed root against the pivot's expected post-catch-up root,
 // so a successful Sync proves the storage mutations were applied in the exact
-// encoding the trie rebuild consumes. verifyTrie re-walks the result as an
+// encoding the trie generation consumes. verifyTrie re-walks the result as an
 // independent confirmation.
 func TestCatchUpAppliesStorageBALs(t *testing.T) {
 	t.Parallel()
@@ -2620,7 +2679,7 @@ func testCatchUpAppliesStorageBALs(t *testing.T, scheme string) {
 	// Sync, so the follow-up Sync's reorg check sees A as still-canonical and
 	// runs catchUp instead of resetting. The A+1 header carries the BAL hash
 	// (verified during catch-up) and the expected post-catch-up state root
-	// (verified by the trie rebuild).
+	// (verified by the trie generation).
 	db := rawdb.NewMemoryDatabase()
 	numA := uint64(128)
 	emptyH := common.Hash{}
@@ -2644,7 +2703,7 @@ func testCatchUpAppliesStorageBALs(t *testing.T, scheme string) {
 	rawdb.WriteHeader(db, hdrB)
 	rawdb.WriteCanonicalHash(db, hdrB.Hash(), numA+1)
 
-	// Sync 1: full flat-state download + trie rebuild against pivot A.
+	// Sync 1: full flat-state download + trie generation against pivot A.
 	{
 		var (
 			once   sync.Once
@@ -2665,7 +2724,7 @@ func testCatchUpAppliesStorageBALs(t *testing.T, scheme string) {
 		}
 		close(done)
 	}
-	// Sanity: the rebuilt trie for pivot A is complete and matches rootA. This
+	// Sanity: the generated trie for pivot A is complete and matches rootA. This
 	// also confirms the test fixture itself is internally consistent.
 	verifyTrie(scheme, db, rootA, t)
 
@@ -2690,6 +2749,12 @@ func testCatchUpAppliesStorageBALs(t *testing.T, scheme string) {
 		if err := syncer.Sync(hdrB, cancel); err != nil {
 			t.Fatalf("pivot A+1 catch-up sync failed: %v", err)
 		}
+		// The freeze must re-arm on a pivot-moved cycle too, the downloader
+		// relies on it from download completion until commit, and it must
+		// point at the new pivot the catch-up rolled forward to.
+		if frozen := syncer.FrozenPivot(); frozen == nil || frozen.Hash() != hdrB.Hash() {
+			t.Fatal("pivot not frozen at the new header after catch-up sync")
+		}
 		close(done)
 	}
 

triedb/generate.go

@@ -337,7 +337,7 @@ func hashRanges(total int) [][2]common.Hash {
 	return ranges
 }
 
-// GenerateTrie rebuilds all tries (storage + account) from flat snapshot
+// GenerateTrie builds all tries (storage + account) from flat snapshot
 // data in the database. The account hash space is partitioned into 16
 // slices aligned with the first-nibble branching of the MPT root. Each
 // partition is processed by its own goroutine, which walks its slice,
@@ -346,10 +346,8 @@ func hashRanges(total int) [][2]common.Hash {
 // trie. Once every partition has produced its subtree root, the top-level
 // branch is assembled and its hash verified against the expected root.
 //
-// Resume: on entry, any partition that has a "done" marker from a
+// Generation is all or nothing: an interrupted run leaves no resume
-// previous run is skipped. Its subtree blob is read from the marker
+// state and the next run builds every partition from scratch.
-// and handed to assembleRoot directly. On a mid-run crash, only the
-// in-flight partition(s) are redone.
 func GenerateTrie(db ethdb.Database, scheme string, root common.Hash, cancel <-chan struct{}) (GenerateStats, error) {
 	var (
 		start        = time.Now()
@@ -366,9 +364,8 @@ func GenerateTrie(db ethdb.Database, scheme string, root common.Hash, cancel <-c
 	go tickProgress(progressDone, start, &scanned, &updated, &progress)
 	defer close(progressDone)
 
-	// For each partition, either skip (prior done marker found) or run
+	// Run every partition concurrently, each producing the subtree root
-	// it. Prior runs can leave the partition's raw root blob in the done
+	// blob that assembleRoot needs.
-	// marker. We recover it here so assembleRoot has everything it needs.
 	var (
 		ranges  = hashRanges(numPartitions)
 		eg, ctx = errgroup.WithContext(context.Background())
@@ -376,11 +373,6 @@ func GenerateTrie(db ethdb.Database, scheme string, root common.Hash, cancel <-c
 	for i, r := range ranges {
 		partition := byte(i)
 		rangeStart, rangeEnd := r[0], r[1]
-		if blob, ok := rawdb.ReadGenerateTriePartitionDone(db, partition); ok {
-			partitionBlobs[partition] = blob
-			progress[partition].Store(partitionFinished)
-			continue
-		}
 		eg.Go(func() error {
 			start := time.Now()
 			blob, err := generatePartition(ctx, cancel, db, scheme, partition, rangeStart, rangeEnd, &scanned, &updated, &deleted, &progress[partition])
@@ -391,11 +383,6 @@ func GenerateTrie(db ethdb.Database, scheme string, root common.Hash, cancel <-c
 
 			progress[partition].Store(partitionFinished)
 			partitionBlobs[partition] = blob
-
-			// Record completion only after the partition's batch has
-			// flushed inside generatePartition, so this marker appears
-			// on disk only when every write the partition did is durable.
-			rawdb.WriteGenerateTriePartitionDone(db, partition, blob)
 			return nil
 		})
 	}
@@ -405,9 +392,8 @@ func GenerateTrie(db ethdb.Database, scheme string, root common.Hash, cancel <-c
 		return GenerateStats{}, err
 	}
 
-	// Assemble the top-level root from the partition blobs, verify it
+	// Assemble the top-level root from the partition blobs and verify it
-	// matches the expected root, and clear all partition markers on
+	// matches the expected root.
-	// success.
 	got, err := assembleRoot(db, scheme, partitionBlobs)
 	if err != nil {
 		return GenerateStats{}, fmt.Errorf("assemble root: %w", err)
@@ -415,15 +401,6 @@ func GenerateTrie(db ethdb.Database, scheme string, root common.Hash, cancel <-c
 	if got != root {
 		return GenerateStats{}, fmt.Errorf("state root mismatch: got %x, want %x", got, root)
 	}
-
-	// Clear the partition progress marker, ending the generation process.
-	batch := db.NewBatch()
-	for i := range numPartitions {
-		rawdb.DeleteGenerateTriePartitionDone(batch, byte(i))
-	}
-	if err := batch.Write(); err != nil {
-		return GenerateStats{}, fmt.Errorf("clear partition markers: %w", err)
-	}
 	log.Info("Generated state trie", "scanned", scanned.Load(), "updated", updated.Load(), "dangling-slots", deleted.Load(), "elapsed", common.PrettyDuration(time.Since(start)))
 	return GenerateStats{
 		Scanned: scanned.Load(),

triedb/generate_test.go

@@ -370,97 +370,6 @@ func TestGenerateTrieOrphanStorage(t *testing.T) {
 	}
 }
 
-// TestGenerateTriePartialResume proves that the resume path actually
-// fires when a partition's done marker is present.
-func TestGenerateTriePartialResume(t *testing.T) {
-	// Build the account set. Empty storage keeps the test focused on the
-	// account-trie resume path.
-	const n = 200
-	accounts := make([]testAccount, 0, n)
-	for i := 0; i < n; i++ {
-		addr := common.BytesToAddress([]byte{byte(i >> 8), byte(i)})
-		hash := crypto.Keccak256Hash(addr[:])
-		accounts = append(accounts, testAccount{
-			hash: hash,
-			account: types.StateAccount{
-				Nonce:    uint64(i),
-				Balance:  uint256.NewInt(uint64(i + 1)),
-				Root:     types.EmptyRootHash,
-				CodeHash: types.EmptyCodeHash.Bytes(),
-			},
-		})
-	}
-	expectedRoot := buildExpectedRoot(t, accounts)
-
-	for _, scheme := range []string{rawdb.HashScheme, rawdb.PathScheme} {
-		t.Run(scheme, func(t *testing.T) {
-			db := rawdb.NewMemoryDatabase()
-
-			// Step 1: write the account snapshots for this run.
-			for _, a := range accounts {
-				rawdb.WriteAccountSnapshot(db, a.hash, types.SlimAccountRLP(a.account))
-			}
-
-			// Step 2: run every partition once to populate trie nodes on disk
-			// and capture each partition's raw root blob.
-			var (
-				scanned atomic.Int64
-				updated atomic.Int64
-				deleted atomic.Int64
-			)
-			ranges := hashRanges(numPartitions)
-			blobs := make([][]byte, numPartitions)
-			for i, r := range ranges {
-				var pos atomic.Uint64
-				blob, err := generatePartition(context.Background(), nil, db, scheme, byte(i), r[0], r[1], &scanned, &updated, &deleted, &pos)
-				if err != nil {
-					t.Fatalf("pre-run partition %d: %v", i, err)
-				}
-				blobs[i] = blob
-			}
-
-			// Step 3: pre-seed done markers for even partitions only.
-			for i := 0; i < numPartitions; i++ {
-				if i%2 == 0 {
-					rawdb.WriteGenerateTriePartitionDone(db, byte(i), blobs[i])
-				}
-			}
-
-			// Step 4: delete flat-state account snapshots for every account that
-			// lives in an even partition. After this, rerunning generatePartition for
-			// an even partition would find no accounts and produce a nil blob,
-			// so a correct final root requires the resume path.
-			numDeleted := 0
-			for _, a := range accounts {
-				if (a.hash[0]>>4)%2 == 0 {
-					rawdb.DeleteAccountSnapshot(db, a.hash)
-					numDeleted++
-				}
-			}
-			if numDeleted == 0 {
-				t.Fatal("test setup failure: no accounts fell in even partitions")
-			}
-
-			// Step 5: run GenerateTrie. Success implies resume actually consulted
-			// the markers. Without it, even partitions would yield nil blobs and
-			// the root check inside GenerateTrie would fail.
-			if _, err := GenerateTrie(db, scheme, expectedRoot, nil); err != nil {
-				t.Fatalf("partial-resume GenerateTrie failed: %v", err)
-			}
-
-			// All markers cleared on success.
-			for i := 0; i < numPartitions; i++ {
-				if _, ok := rawdb.ReadGenerateTriePartitionDone(db, byte(i)); ok {
-					t.Errorf("partition %d marker not cleared after successful resume", i)
-				}
-			}
-			if scheme == rawdb.PathScheme {
-				assertCanonicalNodes(t, db, accounts)
-			}
-		})
-	}
-}
-
 // TestHashRanges checks that hashRanges fully and contiguously covers the
 // 256-bit hash space, with the last range absorbing the rounding remainder.
 func TestHashRanges(t *testing.T) {