core, cmd, trie: fix the condition of pathdb initialization (#28718)

Original problem was caused by #28595, where we made it so that as soon as we start to sync, the root of the disk layer is deleted. That is not wrong per se, but another part of the code uses the "presence of the root" as an init-check for the pathdb. And, since the init-check now failed, the code tried to re-initialize it which failed since a sync was already ongoing.

The total impact being: after a state-sync has begun, if the node for some reason is is shut down, it will refuse to start up again, with the error message: `Fatal: Failed to register the Ethereum service: waiting for sync.`. 

This change also modifies how `geth removedb` works, so that the user is prompted for two things: `state data` and `ancient chain`. The former includes both the chaindb aswell as any state history stored in ancients. 

---------

Co-authored-by: Martin HS <martin@swende.se>

core/rawdb/ancient_scheme.go

@@ -68,14 +68,14 @@ var stateFreezerNoSnappy = map[string]bool{
 
 // The list of identifiers of ancient stores.
 var (
-	chainFreezerName = "chain" // the folder name of chain segment ancient store.
-	stateFreezerName = "state" // the folder name of reverse diff ancient store.
+	ChainFreezerName = "chain" // the folder name of chain segment ancient store.
+	StateFreezerName = "state" // the folder name of reverse diff ancient store.
 )
 
 // freezers the collections of all builtin freezers.
-var freezers = []string{chainFreezerName, stateFreezerName}
+var freezers = []string{ChainFreezerName, StateFreezerName}
 
 // NewStateFreezer initializes the freezer for state history.
 func NewStateFreezer(ancientDir string, readOnly bool) (*ResettableFreezer, error) {
-	return NewResettableFreezer(filepath.Join(ancientDir, stateFreezerName), "eth/db/state", readOnly, stateHistoryTableSize, stateFreezerNoSnappy)
+	return NewResettableFreezer(filepath.Join(ancientDir, StateFreezerName), "eth/db/state", readOnly, stateHistoryTableSize, stateFreezerNoSnappy)
 }

core/rawdb/ancient_utils.go

@@ -81,14 +81,14 @@ func inspectFreezers(db ethdb.Database) ([]freezerInfo, error) {
 	var infos []freezerInfo
 	for _, freezer := range freezers {
 		switch freezer {
-		case chainFreezerName:
-			info, err := inspect(chainFreezerName, chainFreezerNoSnappy, db)
+		case ChainFreezerName:
+			info, err := inspect(ChainFreezerName, chainFreezerNoSnappy, db)
 			if err != nil {
 				return nil, err
 			}
 			infos = append(infos, info)
 
-		case stateFreezerName:
+		case StateFreezerName:
 			if ReadStateScheme(db) != PathScheme {
 				continue
 			}
@@ -102,7 +102,7 @@ func inspectFreezers(db ethdb.Database) ([]freezerInfo, error) {
 			}
 			defer f.Close()
 
-			info, err := inspect(stateFreezerName, stateFreezerNoSnappy, f)
+			info, err := inspect(StateFreezerName, stateFreezerNoSnappy, f)
 			if err != nil {
 				return nil, err
 			}
@@ -125,9 +125,9 @@ func InspectFreezerTable(ancient string, freezerName string, tableName string, s
 		tables map[string]bool
 	)
 	switch freezerName {
-	case chainFreezerName:
+	case ChainFreezerName:
 		path, tables = resolveChainFreezerDir(ancient), chainFreezerNoSnappy
-	case stateFreezerName:
+	case StateFreezerName:
 		path, tables = filepath.Join(ancient, freezerName), stateFreezerNoSnappy
 	default:
 		return fmt.Errorf("unknown freezer, supported ones: %v", freezers)

core/rawdb/database.go

@@ -178,7 +178,7 @@ func resolveChainFreezerDir(ancient string) string {
 	// sub folder, if not then two possibilities:
 	// - chain freezer is not initialized
 	// - chain freezer exists in legacy location (root ancient folder)
-	freezer := path.Join(ancient, chainFreezerName)
+	freezer := path.Join(ancient, ChainFreezerName)
 	if !common.FileExist(freezer) {
 		if !common.FileExist(ancient) {
 			// The entire ancient store is not initialized, still use the sub