[9fans] allowing space (ASCII 0x20) in file names

[Tom Duff td@pixar.com]

> NAMELEN = 28
> FNAMELEN = 64? 128? 256!?  Hell, might as well fix it now. 256.
>
> In that case the overhead for 9p now gets quite high given all
> the Twalks.  So how about a uchar length followed by data?  Makes
> sense.
>
> Boy, the fileserver needs a much bigger inode.  I don't see any way
> around it.  Of course DIRPERBUF gets a lot smaller.  It's good I
> have indexes.
>
> And another thing, there is enough about Plan9 that the user needs
> to be aware of, might as well add spaces to file names so the DOS
> weenys don't eat your lunch when you do IMAP and CIFS...

It's ludicrous to make an incompatible change like this with, as you noted,
such far-reaching consequences, just for one weird little application.
If your application doesn't like the names the file system gives it,
keep a little name-mapping table somewhere and write open and create
routines that use it.