diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 558c23957f..e2c5759d94 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1601,6 +1601,7 @@ static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
     int l2_index;
     int ret;
     int i;
+    bool unmap = !!(flags & BDRV_REQ_MAY_UNMAP);
 
     ret = get_cluster_table(bs, offset, &l2_table, &l2_index);
     if (ret < 0) {
@@ -1613,12 +1614,22 @@ static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
 
     for (i = 0; i < nb_clusters; i++) {
         uint64_t old_offset;
+        QCow2ClusterType cluster_type;
 
         old_offset = be64_to_cpu(l2_table[l2_index + i]);
 
-        /* Update L2 entries */
+        /*
+         * Minimize L2 changes if the cluster already reads back as
+         * zeroes with correct allocation.
+         */
+        cluster_type = qcow2_get_cluster_type(old_offset);
+        if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN ||
+            (cluster_type == QCOW2_CLUSTER_ZERO_ALLOC && !unmap)) {
+            continue;
+        }
+
         qcow2_cache_entry_mark_dirty(bs, s->l2_table_cache, l2_table);
-        if (old_offset & QCOW_OFLAG_COMPRESSED || flags & BDRV_REQ_MAY_UNMAP) {
+        if (cluster_type == QCOW2_CLUSTER_COMPRESSED || unmap) {
             l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
             qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST);
         } else {