Re: NCPFS and brittle connections

[Petr Vandrovec <vandrove@vc.cvut.cz>]

Pierre Ossman wrote:
> Petr Vandrovec wrote:
> > Nobody is working on it (at least to my knowledge), and to me it is
> > feature - it always worked this way, like smbfs did back in the past -
> > if you send signal 9 to process using mount point, and there is some
> > transaction in progress, nobody can correctly finish that transaction
> > anymore.  Fixing it would require non-trivial amount of code, and
> > given that NCP itself is more or less dead protocol I do not feel that
> > it is necessary.
>
> Someone needs to tell our customers then so they'll stop using it. :)

When I asked at Brainshare 2001 when support for files over 4GB files 
will be added to NCP, they told me that I should switch to CIFS or 
NFS...  Years after that confirmed it - only NW6.5SP3 finally got NCPs 
to support for files over 4GB, although you could have such files even 
on NW5.

> > If you want to fix it, feel free.  Culprit is RQ_INPROGRESS handling
> > in ncp_abort_request - it just aborts whole connection so it does not
> > have to provide temporary buffers and special handling for reply - as
> > buffers currently specified as reply buffers are owned by caller, so
> > after aborting request you cannot use them anymore.
>
> Do you have any pointers to how it was solved with smbfs? Relevant
> patches perhaps? Provided a similar solution can be applied here.

I believe it was fixed when smbiod was introduced.  When find_request() 
returns failure, it simple throws away data received from network.

Unfortunately NCP does not run on top of TCP stream, but on top of 
IPX/UDP, and so dropping reply is not sufficient - you must continue 
resending request (so you must buffer it somewhere...) until you get 
result from server - after you receive answer from server, you can 
finally throw away both request & reply, and move on.
							Petr


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/