This is the start of the ext3 scalability rework.  It basically comes in two
halves:

- ext3 BKL/lock_super removal and scalable inode/block allocators

- JBD locking rework.

The ext3 scalability work was completed a couple of months ago.

The JBD rework has been stable for a couple of weeks now.  My gut feeling is
that there should be one, maybe two bugs left in it, but no problems have
been discovered...


Performance-wise, throughput is increased by up to 2x on dual CPU.  10x on
16-way has been measured.  Given that current ext3 is able to chew two whole
CPUs spinning on locks on a 4-way, that wasn't especially suprising.

These patches were prepared by Alex Tomas <bzzz@tmi.comex.ru> and myself.


First patch: ext3 lock_kernel() removal.

The only reason why ext3 takes lock_kernel() is because it is requires by the
JBD API.

The patch removes the lock_kernels() from ext3 and pushes them down into JBD
itself.