Re: [Nbd] found bug in nbd-server.c, handle_info()

[Wouter Verhelst <w@...112...>]

Hi Greg,

On Thu, May 11, 2017 at 09:53:54AM -0400, Menke, Gregory D. (GSFC-582.0)[Arctic Slope Technical Services, Inc.] wrote:
> Thanks Wouter,
> 
> I'm chasing another issue seen both on the trunk and 3.15.2 where an 
> apparent deadlock occurs, leaving the nbd device jammed until the 
> filesystem op, client and server are SIGKILLed at which point the mount 
> can be cleaned up.  In this case the tcp connection is running thru an 
> ssh tunnel over a wan,

In that case, you're stacking TCP over TCP, which does not work very
well. See http://sites.inka.de/~W1011/devel/tcp-tcp.html for a pretty
good (technical) explanation on why that is the case.

If you stack it over UDP instead (e.g., with OpenVPN), you should be
fine.

-- 
< ron> I mean, the main *practical* problem with C++, is there's like a dozen
       people in the world who think they really understand all of its rules,
       and pretty much all of them are just lying to themselves too.
 -- #debian-devel, OFTC, 2016-02-12