diff --git a/ChangeLog b/ChangeLog
index 16c6ef6e8..6c0f03b7f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2013-11-13  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/fs/zfs/zfs.c (ZAP_LEAF_NUMCHUNKS): Use unsigned arithmetics.
+
 2013-11-13  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/normal/datetime.c (grub_get_weekday): Use if rather than
diff --git a/grub-core/fs/zfs/zfs.c b/grub-core/fs/zfs/zfs.c
index d0a4d9cc7..4d0bde4ce 100644
--- a/grub-core/fs/zfs/zfs.c
+++ b/grub-core/fs/zfs/zfs.c
@@ -129,7 +129,7 @@ LEAF_HASH (int bs, grub_uint64_t h, zap_leaf_phys_t *l)
 static inline int
 ZAP_LEAF_NUMCHUNKS (int bs)
 {
-  return (((1 << bs) - 2 * ZAP_LEAF_HASH_NUMENTRIES (bs)) /
+  return (((1U << bs) - 2 * ZAP_LEAF_HASH_NUMENTRIES (bs)) /
 	  ZAP_LEAF_CHUNKSIZE - 2);
 }