diff --git a/lib/storage/index_db.go b/lib/storage/index_db.go
index 0e6ea2a92..4d9ec3cd5 100644
--- a/lib/storage/index_db.go
+++ b/lib/storage/index_db.go
@@ -258,19 +258,20 @@ func (db *indexDB) UpdateMetrics(m *IndexDBMetrics) {
 	})
 }
 
-func (db *indexDB) doExtDB(f func(extDB *indexDB)) bool {
+// doExtDB calls f for non-nil db.extDB.
+//
+// f isn't called if db.extDB is nil.
+func (db *indexDB) doExtDB(f func(extDB *indexDB)) {
 	db.extDBLock.Lock()
 	extDB := db.extDB
 	if extDB != nil {
 		extDB.incRef()
 	}
 	db.extDBLock.Unlock()
-	if extDB == nil {
-		return false
+	if extDB != nil {
+		f(extDB)
+		extDB.decRef()
 	}
-	f(extDB)
-	extDB.decRef()
-	return true
 }
 
 // SetExtDB sets external db to search.
@@ -1505,7 +1506,7 @@ func (db *indexDB) searchMetricNameWithCache(dst []byte, metricID uint64) ([]byt
 	}
 
 	// Try searching in the external indexDB.
-	if db.doExtDB(func(extDB *indexDB) {
+	db.doExtDB(func(extDB *indexDB) {
 		is := extDB.getIndexSearch(noDeadline)
 		dst, ok = is.searchMetricName(dst, metricID)
 		extDB.putIndexSearch(is)
@@ -1514,7 +1515,8 @@ func (db *indexDB) searchMetricNameWithCache(dst []byte, metricID uint64) ([]byt
 			// since the filtering must be performed before calling this func.
 			extDB.putMetricNameToCache(metricID, dst)
 		}
-	}) && ok {
+	})
+	if ok {
 		return dst, true
 	}
 
diff --git a/lib/storage/storage.go b/lib/storage/storage.go
index c3996f137..bf0e3a233 100644
--- a/lib/storage/storage.go
+++ b/lib/storage/storage.go
@@ -389,11 +389,11 @@ func (s *Storage) CreateSnapshot() (string, error) {
 	dirsToRemoveOnError = append(dirsToRemoveOnError, idbSnapshot)
 
 	var err error
-	ok := idb.doExtDB(func(extDB *indexDB) {
+	idb.doExtDB(func(extDB *indexDB) {
 		prevSnapshot := filepath.Join(idbSnapshot, extDB.name)
 		err = extDB.tb.CreateSnapshotAt(prevSnapshot)
 	})
-	if ok && err != nil {
+	if err != nil {
 		return "", fmt.Errorf("cannot create prev indexDB snapshot: %w", err)
 	}
 	dstIdbDir := filepath.Join(dstDir, indexdbDirname)