With this change, we can now use LUKS and LVM over NBD. There are
some decisions to be made regarding where we should get the fstype
and fsoptions from (DHCP root vs rootfstype= etc), but the basic
functionality is there.
This adds support for a command line option netroot=, which is currently
equivalent to root=. This will allow us to break out handling in NBD and
iSCSI to support constructs such as "root=LABEL=/ netroot=dhcp" to make
use of our block device handling with network attached devices.
iSCSI has not been changed in this patch as I don't currently have a way
to test it.
Probe for NFS and NBD capability before trying to load their modules
in case they are built into the kernel. Ugly use of flag files, but
avoids the need for grep to be on the image.
David Dillow