Most uses of struct xfs_imap are to map and inode to a buffer.  To avoid
copying around the inode location information we should just embedd a
strcut xfs_imap into the xfs_inode.  To make sure it doesn't bloat an
inode the im_len is changed to a ushort, which is fine as that's what
the users exepect anyway.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>