ZFS v15 - user and group quota support

[Martin Matuska]

Thanks to everyone involved in porting ZFS v13 to CURRENT and STABLE.

The latest ZFS v15 has a feature many users have been asking for -
support for user and group quotas.

ZFS changes since v13:
http://www.opensolaris.org/os/community/zfs/version/14/
http://www.opensolaris.org/os/community/zfs/version/15/

ZPL changes since v3 (v3 comes with ZFS v13):
http://www.opensolaris.org/os/community/zfs/version/zpl/4/