koji kernel: "barrier-based sync failed"

[Bruno Wolff III]

On Wed, May 06, 2009 at 09:19:32 -0400,
  "Robert P. J. Day" <rpjday at crashcourse.ca> wrote:
> 
>   JBD: barrier-based sync failed on dm-0:8 - disabling barriers
> 
> i powered down, powered back up, and got further into the boot process
> up to the network initialization, then rapid flashing of ADDRCONF
> messages on the screen, then another hang.
> 
>   thoughts?

Barriers are not supported by some block devices. This includes at least
most software raid and most dm devices. Though I have seen suggestions
that dm devices with one underlying device (in particular dmcrypt)
are getting support for that. I don't know what the current status of
that is.

When you try to use barriers when you can't they just get disabled and
things should still work. The only difference will be if there is a
crash of some kind, in which case some stuff may be written out of
order which might be problematic. This is unlikely to be the cause
of your boot problems.