Let's back out LOADER_ZFS_SUPPORT from STABLE

[Dan Allen]

On 13 Jun 2009, at 5:42 PM, Paul B. Mahol wrote:

> On 6/13/09, Dan Allen <danallen46 at airwired.net> wrote:
>> I have now proven that the recent post June 8th version of
>>
>> 	/usr/src/sys/boot/i386/loader/Makefile
>>
>> causes catastrophic data loss.
>>
>
> I hardly doubt that such change cause loss of data on entire drive.
> There is always old loader to pick up.

How do I get to the old loader when the machine boots and immediately  
stops?  There is no ability at this point in the boot process to try  
and get to the old loader that I know of.  Is there a hidden magic key  
combination that allows this?

You are correct that the bulk of the file system is not touched, but  
the key file partitioning headers get cleared and when you boot off of  
a DVD -- the only way to get to the system that I know of -- and  
inspect the file partitioning via whatever means you try, it shows  
that the root partition is gone.  What was your main file system is  
gone.  I learned after many installs that I could NOT do a newfs(8)  
and the setup program would re-mark things and and files ended up re- 
appearing.

My machine was well backed up so no great loss of data in the end, but  
it has cost me lots of time to get this figured out.

For me the real questions are these:

* Why is my system the only one that this happens on?
* What makes my machine setup different?
* What is the bug in the bootable ZFS loader that munges the partition  
map?

Dan