Increase disk quota of a zone in SmartOS

It is not uncommon to run out of disk space by a zone. Below a zone with uuid 1d52f6bf-d7d1-45f9-bf7b-9f9de7224040 has only 172M of free space.

> zfs list
NAME                                               USED  AVAIL  REFER  MOUNTPOINT
zones                                             80.1G  9.97G   514K  /zones
zones/1d52f6bf-d7d1-45f9-bf7b-9f9de7224040        9.83G   172M  10.4G  /zones/1d52f6bf-d7d1-45f9-bf7b-9f9de7224040

Adding disk space can be done in a jiffy without any downtime to the zone. Just update disk quota to new size greater than existing volume size. vmadm update 1d52f6bf-d7d1-45f9-bf7b-9f9de7224040 quota=15 sets disk quota of the zone to 15G.

> zfs list
NAME                                               USED  AVAIL  REFER  MOUNTPOINT
zones                                             80.2G  9.92G   514K  /zones
zones/1d52f6bf-d7d1-45f9-bf7b-9f9de7224040        9.88G  5.12G  10.4G  /zones/1d52f6bf-d7d1-45f9-bf7b-9f9de7224040

Now the zone got additional 5G on the fly without restart or resize2fs. From man vmadm quota takes type: integer (number of GiB) as value