(try number three, maybe it manages to get through the list this time)
Currently XFS_IFORK_* and XFS_DFORK* are implemented by means of
XFS_CFORK* macros. But given that XFS_IFORK_* operates on an
xfs_inode that embedds and xfs_icdinode_core and XFS_DFORK_* operates
on an xfs_dinode that embedds a xfs_dinode_core one will have to do
endian swapping while the other doesn't. Instead of having the current
mess with the CFORK macros that have byteswapping and non-byteswapping
version (which are inconsistantly named while we're at it) just define
each family of the macros to stand by itself and simplify the whole
matter.
A few direct references to the CFORK variants were cleaned up to
use IFORK or DFORK to make this possible.