--- a/Makefile
+++ b/Makefile
@@ -92,6 +92,7 @@ CFLAGS = $(SUBST_CFLAGS) \
 	 -include include/config.h \
 	 -DBTRFS_FLAT_INCLUDES \
 	 -D_XOPEN_SOURCE=700  \
+	 -D_LARGEFILE64_SOURCE \
 	 -fno-strict-aliasing \
 	 -fPIC \
 	 -Wall \