Move the reservation of delayed allocations, and addition of delalloc
regions to the extent trees into a new helper function.  For now
this adds some twisted goto logic to xfs_bmapi, but that will be
cleaned up in the following patches.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAlex Elder <aelder@sgi.com>