Please add a note to the zfs manpage that even if zfs allow is used to allow a user to mount their own zfs filesystems, that FreeBSD will not allow it unless the sysctl vfs.usermount is set to 1.
The error message zfs returns...
cannot mount 'tank/backup/oscar/pgsql': Insufficient privileges
..provides no hint of what's wrong, either.
Update the zfs manpage. Thanks!
For bugs matching the following criteria:
Status: In Progress Changed: (is less than) 2014-06-01
Reset to default assignee and clear in-progress tags.
Mail being skipped
This is now documented in the handbook.