Block layer discard requests

this is an interesting feature. If Linux implements this well I could see devices showing up
in a few years that internally do a secure wipe when the block if freed.

or a ram-based device that shuffles used sections around to be able to power off unused areas.
(or for that matter, shuffle things on a raid 10 array to power off unneeded drives)

and with the scsi target patches that are out there giving you the ability to use a full linux
box as a drive for other systems people wouldn't have to wait for the drive manufacturers to
develop all of this.

this could get _very_ interesting