When no iocharset is specified, the default action is to trivially
map each byte into the low order of the 16-bit unicode character.
If an existing name exists that has a non-zero high order byte, the
file will be inaccessible without remounting with iocharset set to
a charset that supports the character.

This patch will cause a warning to be issued to the syslog (no more
than five times) suggesting that the volume be mounted with
iocharset=utf8 in order to access the file.