void	fmerge(Dptr*, char*, char*, int, int);
int	fbwrite(Icache*, Ibuf*, char*, ulong, int);
long	fwrite(Icache*, Ibuf*, char*, ulong, long);
Dptr*	fpget(Icache*, Ibuf*, ulong);
long	fread(Icache*, Ibuf*, char*, ulong, long);