libxfs: resync libxfs_alloc_file_space interface with the kernel

Make the userspace xfs_alloc_file_space behave (more or less) like the
kernel version, at least as far as the interface goes.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
3 files changed