[syslinux] extlinux-4.0 can't boot on our platform.

[H. Peter Anvin]

On 07/07/2010 08:42 AM, H. Peter Anvin wrote:
> On 07/06/2010 11:33 PM, 孤云独闲 wrote:
>> Hi all:
>>      my filesystem is btrfs. /boot and / is  on the same
>> partition(/dev/sda2,
>> format btrfs).  i install syslinux as following:
>>       1.  rpm  -ivh syslinux-4.00-1.i386.rpm
>> syslinux-extlinux-4.00-1.i386.rpm syslinux-tftpboot-4.00-1.i386.rpm
>>       2.  extlinux-i /boot/extlinux. (the extlinux.sys can't be create
>> on the
>> directory).
>>       3.  i copy extlinux.conf to  /boot/extlinux . (of course , i
>> have edit
>> the extlinux.conf)
>>       4. extlinux -U  /boot/extlinux
>>      5.  cat /usr/share/syslinux/mbr.bin>/dev/sda.
>>
>> i reboot , but the system can't boot,  the screen show tips "No
>> DEFAULT or
>> UI configuration directive found!" , i doubt mbr isn't installed.
>>      do you tell me why and what  i do next?
>>
> 
> Are you using compressed btrfs?  We don't handle that yet.
> 

A bit of clarification:

The plan for btrfs was (and still is) for compression to be per
subvolume, which would naturally have lent itself to /boot being a
subvolume with no compression.  Unfortunately, this has not yet gotten
implemented in btrfs, which means we're a bit stuck.

I'm currently looking at adding compression support to Syslinux, but it
is a nontrivial undertaking.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.