[PATCH] mkfs: add discard support

[Dave Chinner]

On Tue, Oct 06, 2009 at 02:47:58PM -0400, Christoph Hellwig wrote:
> Call the BLKDISCARD ioctl to mark the whole disk as unused before creating
> a new filesystem.  This will allow SSDs, Arrays with thin provisioning support
> and virtual machines to make smarter allocation decisions.

Good idea, but perhaps the discard should be optional rather than
unconditional.  My immediate thought was the SOP for setting up
encrypted devices - fill the empty disk with random data before
setting up the encrypted device. If you then send it a discard....

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com