Querying jailed ZFSes

So, I can give a jail control over a section of my ZFS pool:

    zfs set jailed=on zroot/poudriere
    zfs jail pkg.infracaninophile.co.uk zroot/poudriere

and all that works absolutely perfectly.  But I can't see any way after 
doing that to query ZFS and get a report on what ZFSes have been jailed 
where.  All I can see is the state of the `jailed` property:

    % zfs get jailed zroot/poudriere
    NAME             PROPERTY  VALUE   SOURCE
    zroot/poudriere  jailed    on      local

No mention anywhere of the jail name or JID I can see? Is this possible?

	Cheers,

	Matthew