diff --git a/ext2fs/pager.c b/ext2fs/pager.c
index 6e99c83..4ea4b74 100644
--- a/ext2fs/pager.c
+++ b/ext2fs/pager.c
@@ -398,8 +398,10 @@ file_pager_write_page (struct node *node, vm_offset_t offset, void *buf)
       err = find_block (node, offset, &block, &lock);
       if (err)
 	break;
-      assert (block);
-      pending_blocks_add (&pb, block);
+      if (block)
+	pending_blocks_add (&pb, block);
+      else
+	pending_blocks_skip (&pb);
       offset += block_size;
       left -= block_size;
     }