$ mkdir d
$ cd d

$ whoami
> root

$ touch a
	
Neet to have write_acl permission to chmod or set the acl:
	$ su bin
	$ chmod 666 a
	> chmod: changing permissions of `a': Operation not permitted
	$ nfs4acl --set 'bin:rwM::allow' a
	> a: Operation not permitted
	
$ su
$ nfs4acl --set 'bin:rwm::allow' a
	
Can set the acl now:
	$ su bin
	$ nfs4acl --set 'bin:rwm::allow' a
	
A chmod limits the permissions to the specified mode, which always disables
write_acl:
	$ chmod 666 a
	$ nfs4acl --set 'bin:rwm::allow' a
	> a: Operation not permitted

$ su
$ cd ..
$ rm -rf d