swarm/storage: fix garbage collector index skew (#18080)

On file access LDBStore's tryAccessIdx() function created a faulty
GC Index Data entry, because not indexing the ikey correctly.
That caused the chunk addresses/hashes to start with '00' and the last
two digits were dropped. => Incorrect chunk address.

Besides the fix, the commit also contains a schema change which will
run the CleanGCIndex() function to clean the GC index from erroneous
entries.

Note: CleanGCIndex() rebuilds the index from scratch which can take
a really-really long time with a huge DB (possibly an hour).

1 files changed, 32 insertions, 15 deletions

diff --git a/swarm/storage/localstore.go b/swarm/storage/localstore.go
index 6971d759e..fa98848dd 100644
--- a/swarm/storage/localstore.go
+++ b/swarm/storage/localstore.go
@@ -196,31 +196,48 @@ func (ls *LocalStore) Close() {
 
 // Migrate checks the datastore schema vs the runtime schema, and runs migrations if they don't match
 func (ls *LocalStore) Migrate() error {
-	schema, err := ls.DbStore.GetSchema()
+	actualDbSchema, err := ls.DbStore.GetSchema()
 	if err != nil {
 		log.Error(err.Error())
 		return err
 	}
 
-	log.Debug("found schema", "schema", schema, "runtime-schema", CurrentDbSchema)
-	if schema != CurrentDbSchema {
-		// run migrations
+	log.Debug("running migrations for", "schema", actualDbSchema, "runtime-schema", CurrentDbSchema)
 
-		if schema == "" {
-			log.Debug("running migrations for", "schema", schema, "runtime-schema", CurrentDbSchema)
+	if actualDbSchema == CurrentDbSchema {
+		return nil
+	}
+
+	if actualDbSchema == DbSchemaNone {
+		ls.migrateFromNoneToPurity()
+		actualDbSchema = DbSchemaPurity
+	}
 
-			// delete chunks that are not valid, i.e. chunks that do not pass any of the ls.Validators
-			ls.DbStore.Cleanup(func(c *chunk) bool {
-				return !ls.isValid(c)
-			})
+	if err := ls.DbStore.PutSchema(actualDbSchema); err != nil {
+		return err
+	}
 
-			err := ls.DbStore.PutSchema(DbSchemaPurity)
-			if err != nil {
-				log.Error(err.Error())
-				return err
-			}
+	if actualDbSchema == DbSchemaPurity {
+		if err := ls.migrateFromPurityToHalloween(); err != nil {
+			return err
 		}
+		actualDbSchema = DbSchemaHalloween
 	}
 
+	if err := ls.DbStore.PutSchema(actualDbSchema); err != nil {
+		return err
+	}
 	return nil
 }
+
+func (ls *LocalStore) migrateFromNoneToPurity() {
+	// delete chunks that are not valid, i.e. chunks that do not pass
+	// any of the ls.Validators
+	ls.DbStore.Cleanup(func(c *chunk) bool {
+		return !ls.isValid(c)
+	})
+}
+
+func (ls *LocalStore) migrateFromPurityToHalloween() error {
+	return ls.DbStore.CleanGCIndex()
+}