From d5cad488be0069d768b358b2267cd5432b0f9a43 Mon Sep 17 00:00:00 2001
From: gary rong <garyrong0905@gmail.com>
Date: Fri, 11 Jan 2019 19:49:12 +0800
Subject: [PATCH] core, eth: fix database version (#18429)

* core, eth: fix database version

* eth: polish error message
---
 core/blockchain.go               |  2 +-
 core/rawdb/accessors_metadata.go | 22 +++++++++++++++-------
 eth/backend.go                   |  6 ++++--
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/core/blockchain.go b/core/blockchain.go
index c29063a73..49aedf669 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -65,7 +65,7 @@ const (
 	triesInMemory       = 128
 
 	// BlockChainVersion ensures that an incompatible database forces a resync from scratch.
-	BlockChainVersion = 3
+	BlockChainVersion uint64 = 3
 )
 
 // CacheConfig contains the configuration values for the trie caching/pruning
diff --git a/core/rawdb/accessors_metadata.go b/core/rawdb/accessors_metadata.go
index 3b6e6548d..82e4bf045 100644
--- a/core/rawdb/accessors_metadata.go
+++ b/core/rawdb/accessors_metadata.go
@@ -26,19 +26,27 @@ import (
 )
 
 // ReadDatabaseVersion retrieves the version number of the database.
-func ReadDatabaseVersion(db DatabaseReader) int {
-	var version int
+func ReadDatabaseVersion(db DatabaseReader) *uint64 {
+	var version uint64
 
 	enc, _ := db.Get(databaseVerisionKey)
-	rlp.DecodeBytes(enc, &version)
+	if len(enc) == 0 {
+		return nil
+	}
+	if err := rlp.DecodeBytes(enc, &version); err != nil {
+		return nil
+	}
 
-	return version
+	return &version
 }
 
 // WriteDatabaseVersion stores the version number of the database
-func WriteDatabaseVersion(db DatabaseWriter, version int) {
-	enc, _ := rlp.EncodeToBytes(version)
-	if err := db.Put(databaseVerisionKey, enc); err != nil {
+func WriteDatabaseVersion(db DatabaseWriter, version uint64) {
+	enc, err := rlp.EncodeToBytes(version)
+	if err != nil {
+		log.Crit("Failed to encode database version", "err", err)
+	}
+	if err = db.Put(databaseVerisionKey, enc); err != nil {
 		log.Crit("Failed to store the database version", "err", err)
 	}
 }
diff --git a/eth/backend.go b/eth/backend.go
index 354fc17d4..2a9d56c5c 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -143,8 +143,10 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 
 	if !config.SkipBcVersionCheck {
 		bcVersion := rawdb.ReadDatabaseVersion(chainDb)
-		if bcVersion != core.BlockChainVersion && bcVersion != 0 {
-			return nil, fmt.Errorf("Blockchain DB version mismatch (%d / %d).\n", bcVersion, core.BlockChainVersion)
+		if bcVersion != nil && *bcVersion > core.BlockChainVersion {
+			return nil, fmt.Errorf("database version is v%d, Geth %s only supports v%d", *bcVersion, params.VersionWithMeta, core.BlockChainVersion)
+		} else if bcVersion != nil && *bcVersion < core.BlockChainVersion {
+			log.Warn("Upgrade blockchain database version", "from", *bcVersion, "to", core.BlockChainVersion)
 		}
 		rawdb.WriteDatabaseVersion(chainDb, core.BlockChainVersion)
 	}