syntax for deleting subvolumes?

[K Richard Pixley <rpixley@graphitesystems.com>]

I'm having trouble deleting a subvolume.

[root@new-alfred ~]# uname -a
Linux new-alfred.corp.graphitesystems.com 3.10.0-123.el7.x86_64 #1 SMP 
Mon May 5 11:16:57 EDT 2014 x86_64 x86_64 x86_64 GNU/Linux
[root@new-alfred ~]#   btrfs --version
Btrfs v3.16.2
[root@new-alfred ~]#   btrfs fi show
Label: 'rhel_bark'  uuid: d3c6c783-c190-4675-99f2-b83f3c462656
         Total devices 2 FS bytes used 14.25GiB
         devid    1 size 461.38GiB used 7.03GiB path /dev/sda2
         devid    2 size 465.76GiB used 12.01GiB path /dev/sdb1

Btrfs v3.16.2
[root@new-alfred ~]#   btrfs fi df /
Data, single: total=15.01GiB, used=13.19GiB
System, RAID1: total=8.00MiB, used=16.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, RAID1: total=2.00GiB, used=1.07GiB
Metadata, single: total=8.00MiB, used=0.00
[root@new-alfred ~]# btrfs subvolume list /
ID 257 gen 1483 top level 5 path root
ID 258 gen 1466 top level 5 path home
[root@new-alfred ~]# btrfs subvolume delete home
Transaction commit: none (default)
ERROR: error accessing 'home'
[root@new-alfred ~]# btrfs subvolume delete /home
Transaction commit: none (default)
ERROR: error accessing '/home'

What format do I need to use to delete the "home" subvolume?

--rich