diff --git a/kernel/treenode/blocktree.go b/kernel/treenode/blocktree.go
index ec43c5b83..a3b8a8f49 100644
--- a/kernel/treenode/blocktree.go
+++ b/kernel/treenode/blocktree.go
@@ -389,23 +389,31 @@ func InitBlockTree(force bool) {
 		return
 	}
 
-	size := uint64(0)
-
+	size := int64(0)
 	waitGroup := &sync.WaitGroup{}
 	p, _ := ants.NewPoolWithFunc(4, func(arg interface{}) {
 		defer waitGroup.Done()
 
 		entry := arg.(os.DirEntry)
 		p := filepath.Join(util.BlockTreePath, entry.Name())
-		data, err := os.ReadFile(p)
+
+		f, err := os.OpenFile(p, os.O_RDONLY, 0644)
 		if nil != err {
-			logging.LogErrorf("read block tree failed: %s", err)
+			logging.LogErrorf("open block tree failed: %s", err)
 			os.Exit(logging.ExitCodeFileSysErr)
 			return
 		}
 
+		info, err := f.Stat()
+		if nil != err {
+			logging.LogErrorf("stat block tree failed: %s", err)
+			os.Exit(logging.ExitCodeFileSysErr)
+			return
+		}
+		size += info.Size()
+
 		sliceData := map[string]*BlockTree{}
-		if err = msgpack.Unmarshal(data, &sliceData); nil != err {
+		if err = msgpack.NewDecoder(f).Decode(&sliceData); nil != err {
 			logging.LogErrorf("unmarshal block tree failed: %s", err)
 			if err = os.RemoveAll(util.BlockTreePath); nil != err {
 				logging.LogErrorf("removed corrupted block tree failed: %s", err)
@@ -414,9 +422,14 @@ func InitBlockTree(force bool) {
 			return
 		}
 
+		if err = f.Close(); nil != err {
+			logging.LogErrorf("close block tree failed: %s", err)
+			os.Exit(logging.ExitCodeFileSysErr)
+			return
+		}
+
 		name := entry.Name()[0:strings.Index(entry.Name(), ".")]
 		blockTrees.Store(name, &btSlice{data: sliceData, changed: time.Time{}, m: &sync.Mutex{}})
-		size += uint64(len(data))
 	})
 	for _, entry := range entries {
 		if !strings.HasSuffix(entry.Name(), ".msgpack") {
@@ -432,7 +445,7 @@ func InitBlockTree(force bool) {
 
 	debug.FreeOSMemory()
 	elapsed := time.Since(start).Seconds()
-	logging.LogInfof("read block tree [%s] to [%s], elapsed [%.2fs]", humanize.Bytes((size)), util.BlockTreePath, elapsed)
+	logging.LogInfof("read block tree [%s] to [%s], elapsed [%.2fs]", humanize.Bytes(uint64(size)), util.BlockTreePath, elapsed)
 	return
 }