I was trying to figure out why disklabel doesn't like vnd* devices, and
discovered that the vnode disk driver in sys/dev/vn.c doesn't support
the DIOC* ioctl's used by disklabel, and returns ENXIO for unsupported
ioctl() calls.  Most of the other drivers I looked at return ENOTTY for
unrecognised ioctl() calls, but kernfs returns EOPNOTSUPP.  Is there a
good reason for these differences, or is it a bug?

--apb (Alan Barrett)

------------------------------------------------------------------------------