diff --git a/fs/reiserfs/reiserfs.h b/fs/reiserfs/reiserfs.h
index 48835a659948..ae4811fecc1f 100644
--- a/fs/reiserfs/reiserfs.h
+++ b/fs/reiserfs/reiserfs.h
@@ -1916,7 +1916,7 @@ struct reiserfs_de_head {
 
 /* empty directory contains two entries "." and ".." and their headers */
 #define EMPTY_DIR_SIZE \
-(DEH_SIZE * 2 + ROUND_UP (strlen (".")) + ROUND_UP (strlen ("..")))
+(DEH_SIZE * 2 + ROUND_UP (sizeof(".") - 1) + ROUND_UP (sizeof("..") - 1))
 
 /* old format directories have this size when empty */
 #define EMPTY_DIR_SIZE_V1 (DEH_SIZE * 2 + 3)