Re: nbd-server

[Wouter Verhelst]

On Fri, 28 Sep 2001, Roland McGrath wrote:

> I took a quick look at nbd and it's so simple that I just implemented the
> client side for the Hurd.  That is, I've added an "nbd" store type to 
> libstore.
> So to use it do e.g.:
> 
>       settrans /dev/nb0 /hurd/storeio -Tnbd hostname:1234
> 
> to connect to TCP port 1234 on "hostname".  That gives the store a
> blocksize of 1, since the server protocol doesn't impose any.
> You can set the block size of the store in the name, e.g.:
> 
>       settrans /dev/nb0 /hurd/storeio -Tnbd hostname:1234/1024
> 
> does the same as the above, but the resulting device will have a block size
> of 1024 (the default for Linux nbd devices).
> 
> As usual, I've compiled this but not tested it at all.  I'm sure there are
> some stupid bugs.  Hurd folks, please give this a try if you feel like it
> (you can point it at nbd-server on your Linux machine).

Looks great; however, I do have a couple questions:
- Where can I find the code? ;-)
- Pavel Machek, the author of NBD under Linux has put special effort in
  making his code deadlock-free in case the block device is used as 
  swapspace device (a deadlock could arise if nbd-client needs more memory
  to handle the reads necessary to handle a page fault...). Did you think
  about this situation, or should I consider your port as "not deadlock
  safe"?

-- 
wouter dot verhelst at advalvas dot be

"Human knowledge belongs to the world"
  -- From the movie "Antitrust"

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