diff --git a/block/qcow2.h b/block/qcow2.h
index 601c2e4c82..0942126232 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -83,7 +83,7 @@
 
 /* Defined in the qcow2 spec (compressed cluster descriptor) */
 #define QCOW2_COMPRESSED_SECTOR_SIZE 512U
-#define QCOW2_COMPRESSED_SECTOR_MASK (~(QCOW2_COMPRESSED_SECTOR_SIZE - 1))
+#define QCOW2_COMPRESSED_SECTOR_MASK (~(QCOW2_COMPRESSED_SECTOR_SIZE - 1ULL))
 
 /* Must be at least 2 to cover COW */
 #define MIN_L2_CACHE_SIZE 2 /* cache entries */