OVL_IMPURE
ovl_set_flag(OVL_IMPURE, inode);
ovl_test_flag(OVL_IMPURE, d_inode(rdd->dentry)))
ovl_clear_flag(OVL_IMPURE, inode);
return od->is_upper && ovl_test_flag(OVL_IMPURE, dir);
ovl_set_flag(OVL_IMPURE, d_inode(root));
if (ovl_test_flag(OVL_IMPURE, d_inode(dentry)))
ovl_set_flag(OVL_IMPURE, d_inode(dentry));