linux-wandboard

sanitize ->fsync() for affs

unfortunately, for affs (especially for affs directories) we have
no real way to keep track of metadata ownership.  So we have to
do more or less what file_fsync() does, but we do *not* need to
call write_super() there.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>