diff --git a/block/mirror.c b/block/mirror.c
index f0b211a9c8..24ede6fdaa 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1185,25 +1185,23 @@ do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
                      uint64_t offset, uint64_t bytes,
                      QEMUIOVector *qiov, int flags)
 {
-    BdrvDirtyBitmapIter *iter;
     QEMUIOVector target_qiov;
-    uint64_t dirty_offset;
-    int dirty_bytes;
+    uint64_t dirty_offset = offset;
+    uint64_t dirty_bytes;
 
     if (qiov) {
         qemu_iovec_init(&target_qiov, qiov->niov);
     }
 
-    iter = bdrv_dirty_iter_new(job->dirty_bitmap);
-    bdrv_set_dirty_iter(iter, offset);
-
     while (true) {
         bool valid_area;
         int ret;
 
         bdrv_dirty_bitmap_lock(job->dirty_bitmap);
-        valid_area = bdrv_dirty_iter_next_area(iter, offset + bytes,
-                                               &dirty_offset, &dirty_bytes);
+        dirty_bytes = MIN(offset + bytes - dirty_offset, INT_MAX);
+        valid_area = bdrv_dirty_bitmap_next_dirty_area(job->dirty_bitmap,
+                                                       &dirty_offset,
+                                                       &dirty_bytes);
         if (!valid_area) {
             bdrv_dirty_bitmap_unlock(job->dirty_bitmap);
             break;
@@ -1259,9 +1257,10 @@ do_sync_target_write(MirrorBlockJob *job, MirrorMethod method,
                 break;
             }
         }
+
+        dirty_offset += dirty_bytes;
     }
 
-    bdrv_dirty_iter_free(iter);
     if (qiov) {
         qemu_iovec_destroy(&target_qiov);
     }