[ Upstream commit b07d5cc93e1b28df47a72c519d09d0a836043613 ] After copy up, we may need to update d_flags if upper dentry is on a remote fs and lower dentries are not. Add helpers to allow incremental update of the revalidate flags. Fixes: bccece1ead36 ("ovl: allow remote upper") Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>