Joyride SD card corruption

[Mikus Grinbergs]

WARNING  -- since about build 2590 I can get my "permanent" SD card 
(ext2 filesystem) completely corrupted - I've had to restore it 
twice.  [This is a regression - with 2583 and earlier I never saw 
any SD corruption.  Note that my systems have multiple USB devices.]

I am unaware of the cause.  Everything seems fine - I type in 
'shutdown -r now' - the XO shuts down and restarts - but hangs 
before showing any of the OFW output lines.  [Looking afterwards 
from a running system at the SD card, the ext2 filesystem on it is 
thoroughly hosed (e.g., 'ls' shows questionmarks;  'fsck' lists 
zillions of deleted inodes, plus incorrect refcounts, etc.).]

mikus