Switch from legacy ata(4) to CAM-based ATA

[Benjamin Kaduk]

On Wed, 20 Apr 2011, Arnaud Lacombe wrote:

> Hi,
>
> On Wed, Apr 20, 2011 at 9:17 PM, Warren Block <wblock at wonkity.com> wrote:
>> On Wed, 20 Apr 2011, Arnaud Lacombe wrote:
>>
>>> On Wed, Apr 20, 2011 at 6:38 PM, Garrett Cooper <yanegomi at gmail.com>
>>> wrote:
>>>>
>>>> On Wed, Apr 20, 2011 at 3:35 PM, Doug Barton <dougb at freebsd.org> wrote:
>>>>
>>>> glabel create <label> /dev/<blah>
>>>
>>> Just tested that with a kernel from HEAD and a 8.x userland. This does
>>> not seem to survive a reboot.
>>
>> No, "create" makes a temporary label.  "label" writes a label to the last
>> block of the device.
>>
> ... which does not seem be doable when the fs is mounted:
>
> [in single-user, with only / mounted r/w and /dev]
> # geom label label root /dev/ad0s1a
> geom: Can't store metadata on /dev/ad0s1a: Operation not permitted.

As an anti-foot-shooting measure, this is blocked unless the flag sysctl 
kern.geom.debugflags |= 16 is set

>
> Unfortunately, I do not have physical access to the machine. I guess
> that transition will be a royal PITA for a lot of people.
>
> Btw, you mentioned "device", I guess you meant "file-system", didn't you ?

The label is on the device, using space that is (hopefully) left over 
after the filesystem's allocation.

-Ben Kaduk