diff --git a/.gitignore b/.gitignore
index bd4937245b..5f21c69b30 100644
--- a/.gitignore
+++ b/.gitignore
@@ -63,3 +63,5 @@ uImage
 .DS_Store
 tools/gdb/__pycache__
 /build
+.ccls-cache
+compile_commands.json
diff --git a/fs/fat/fs_fat32.h b/fs/fat/fs_fat32.h
index afff4598a0..e1d7ce43a9 100644
--- a/fs/fat/fs_fat32.h
+++ b/fs/fat/fs_fat32.h
@@ -261,7 +261,7 @@
 
 #define DIRSEC_NDXMASK(f)   (((f)->fs_hwsectorsize - 1) >> 5)
 #define DIRSEC_NDIRS(f)     (((f)->fs_hwsectorsize) >> 5)
-#define DIRSEC_BYTENDX(f,i) (((i) & DIRSEC_NDXMASK(fs)) << 5)
+#define DIRSEC_BYTENDX(f,i) (((i) & DIRSEC_NDXMASK(f)) << 5)
 
 #define SEC_NDXMASK(f)      ((f)->fs_hwsectorsize - 1)
 #define SEC_NSECTORS(f,n)   ((n) / (f)->fs_hwsectorsize)