[PATCH] xfs: add FITRIM support

[Dave Chinner]

On Sun, Jan 02, 2011 at 02:22:02AM -0500, Christoph Hellwig wrote:
> Allow manual discards from userspace using the FITRIM ioctl.  This is not
> intended to be run during normal workloads, as the freepsace btree walks
> can cause large performance degradation.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> 
> ---
> 
> V1 -> V2
>  
>  - added __user annotations as noted by Alex
>  - removed non-blocking agf read as noted by Alex
>  - update range->len as noted by Alex
> 
> This does not implement the by-bno search or lock break suggestions from
> Dave.  Given that the 2.6.38 window is about to close those seem a bit
> risky to me.  I'll look into these later.

Ok, seemms like a good way to proceed.

Reviewed-by: Dave Chinner <dchinner at redhat.com>

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com