Add the support for a large number of logical volumes.  We will soon have
hardware that support up to 1024 logical volumes.
Signed-off-by: NMike Miller <mike.miller@hp.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>