tree 4f8a98990f946d8d82ffdb4d43c1120cd4e97a26
parent 421463526fd1d8b5cb575baca12667c1005a110b
author Li Dongyang <lidongyang@novell.com> 1320911526 +0800
committer Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 1321640885 -0500

xen-blkback: convert hole punching to discard request on loop devices

As of dfaa2ef68e80c378e610e3c8c536f1c239e8d3ef, loop devices support
discard request now. We could just issue a discard request, and
the loop driver will punch the hole for us, so we don't need to touch
the internals of loop device and punch the hole ourselves, Thanks.

V0->V1: rebased on devel/for-jens-3.3

Signed-off-by: Li Dongyang <lidongyang@novell.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>