Hole Punching V2

[Josef Bacik <josef@xxxxxxxxxx>]

This is version 2 of the hole punching series I posted last week.  The following
things have changed

-Hole punching doesn't change file size
-Fixed the mode checks in ext4/btrfs/gfs2 so they do what they are supposed to

I posted updates to xfstests and xfsprogs in order to test this new interface,
and ran the test on xfs to make sure hole punching worked properly for xfs and I
tested it on btrfs to make sure it failed properly.  This series also adds
support for doing hole punching to ocfs2, but I did not test this part of it,
albiet it's an obvious fix so it should work fine.  Thanks,

Josef