Filesystems being eaten?

Last Friday my 8.0-CURRENT/amd64 box suffered a crash--no idea if
it panicked, I was running X11--after which all filesystems were
so badly corrupted that I had to reinstall the machine.  This was
a vanilla setup, UFS2 and UFS2+S, -CURRENT about a week old at the
time.

Yesterday it crashed again and while other filesystems survived,
/usr was again too damaged for fsck to recover it.  fsck -y showed
thousands of errors in the "unexpected soft update inconsistency"
class, starting with many "partially allocated inode"s, and eventually
asked to be re-run, which produced only more of the same.  I wonder
if fsck didn't cause most of the corruption itself.

I realize this isn't exactly helpful as a bug report, but what can
I do.  Something in -CURRENT from the last two weeks or so, maybe
specific to amd64, maybe not, may eat filesystems.

Since I actually use the box and can't afford to reinstall it once
or twice a week, I've moved it to RELENG_7 for the time being.

-- 
Christian "naddy" Weisgerber                          naddy_at_mips.inka.de