diff --git a/block/qed-check.c b/block/qed-check.c
index ea4ebc8..22cd07f 100644
--- a/block/qed-check.c
+++ b/block/qed-check.c
@@ -18,7 +18,7 @@
     BdrvCheckResult *result;
     bool fix;                           /* whether to fix invalid offsets */
 
-    size_t nclusters;
+    uint64_t nclusters;
     uint32_t *used_clusters;            /* referenced cluster bitmap */
 
     QEDRequest request;
@@ -177,7 +177,7 @@
 static void qed_check_for_leaks(QEDCheck *check)
 {
     BDRVQEDState *s = check->s;
-    size_t i;
+    uint64_t i;
 
     for (i = s->header.header_size; i < check->nclusters; i++) {
         if (!qed_test_bit(check->used_clusters, i)) {
diff --git a/block/qed.h b/block/qed.h
index 3e1ab84..1d1421f 100644
--- a/block/qed.h
+++ b/block/qed.h
@@ -252,7 +252,7 @@
     return offset & (s->header.cluster_size - 1);
 }
 
-static inline unsigned int qed_bytes_to_clusters(BDRVQEDState *s, size_t bytes)
+static inline uint64_t qed_bytes_to_clusters(BDRVQEDState *s, uint64_t bytes)
 {
     return qed_start_of_cluster(s, bytes + (s->header.cluster_size - 1)) /
            (s->header.cluster_size - 1);