while looking at making (part of) readdisklabel() and writedisklabel()
	MI, i've noticed the following:
	- readdisklabel() tries to search for disklabel starting from
	  LABELOFFSET byte within the sector, by checking magic number.
	  so it can end up reading disklabel from some place other than
	  LABELOFFSET.
	- in most cases, writedisklabel() is hardcoded to write disklabel back
	  to LABELOFFSET.

	therefore, writedisklabel() can write disklabel to location which is
	different from readdisklabel() have used.  is it intentional? (to
	force placement of disklabel at LABELOFFSET)  or a mistake where
	writedisklabel() should be corrected to follow the location found
	by readdisklabel()?

	of course, the behavior depends on which port you are looking at.

itojun