bkg-daemon-dont-break-64bit-pointers-and-handle-requests-in-order-20011102

bkg-daemon-dont-break-64bit-pointers-and-handle-requests-in-order-20011102

This patch fixes a problem with 64-bit pointers being munged by the
background daemons (by separating sizes and pointers into separate
variables -- this bug was apparently introduced by the 64-bit file
support patch), and makes the background daemons handle requests in
order they came in.  The latter will be mostly just useful for some
prefetching and fine grained dcache-locking patches