From: Nikita Danilov <Nikita@Namesys.COM>

Some stage in reiserfs balancing (fix_nodes() function) has to be performed
without ever scheduling.  If it schedules, it has to be restarted.  As we
don't want to restart often, we first try to do atomic allocation, and if
it fails, GFP_NOFS allocation is done, and fix_nodes() restarted.