So, I don't think that using utf8 by default is a good idea. I think
that most comfortable would be passing local charset with mount option.
This need including iconv library into kernel to translate names of
files and directories. So iconv library should be in the base system.
Character translation would be very usefull for lots of not-familiar
file systems, such as msdosfs, ntfs iso9660. This won't affect ffs and
other familiar systems, so I think that this can be done.