core: moved mutex locks in insert blocks to start of function

Insert blocks will no longer allow processing of multiple chains at the
same time. The block lock has been moved to start of the function.

core/chain_manager.go

@@ -496,6 +496,9 @@ func (self *ChainManager) procFutureBlocks() {
 }
 
 func (self *ChainManager) InsertChain(chain types.Blocks) error {
+	self.mu.Lock()
+	defer self.mu.Unlock()
+
 	// A queued approach to delivering events. This is generally faster than direct delivery and requires much less mutex acquiring.
 	var (
 		queue      = make([]interface{}, len(chain))
@@ -543,8 +546,6 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
 
 		block.Td = new(big.Int).Set(CalculateTD(block, self.GetBlock(block.ParentHash())))
 
-		self.mu.Lock()
-		{
 		cblock := self.currentBlock
 		// Write block to database. Eventually we'll have to improve on this and throw away blocks that are
 		// not in the canonical chain.
@@ -590,8 +591,6 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
 			queue[i] = ChainSideEvent{block, logs}
 			queueEvent.sideCount++
 		}
-		}
-		self.mu.Unlock()
 
 		stats.processed++