[ENBD] Client freeze with Reiserfs over enbd

[Brian Keefer]

"Peter T. Breuer" wrote:
> 
> "A month of sundays ago Brian Keefer wrote:"
> > I'm using enbd-2.4.31 and linux-2.4.20 on both client and server. I was in
> > X when my system froze, so I only have the system log of the failure. The
> 
> Oh, I see. The usual technique is to have a serial line hooked up and
> to be scrolling the logs to it in realtime via syslog :-). Useful for
> rebooting too.

It's been a while since I messed with RS-232, I remember it being
extremely painful. I'm not even sure if I still have a DTE-DTE cable in
The Big Knot.
 
> 
> If you have the kernel debugger compiled in, you can generally get out
> of jail (blind). Maybe with magic-sysreq too.

With magic sysreq, moya couldn't sync or unmount it's disk. I could only
Sysrq-b, and offer my humble thanks to Hans Reiser, Patron Saint of Fast
Booting.


> > Here's the syslog from the crash
...
> 
> Isn't that interesting. The reply came in, but 13s late!
> 
> What could do that?

Umm, well, the Server here is supposed to be a diskless mediastation,
shangai'd into being a cheap external IDE enclosure. The Server's
enbd-server binary is being Samba'd in from moya. I know Linux's IO sorter
sucks, but it wasn't too busy to allow samba to reply to enbd-server being
paged in. 

> 
> Anyway, the client daemon was also OK. It treated the reply.
> 
> > > May 11 23:11:17 moya syslogd 1.3-3: restart.
> 
> Yerrs. Maybe I should look at what happens in that pathway. At least I
> should maybe flag the request so that positive news is logged when
> it does finally get treated.
> 
> It's quite possible it's a bug.
> 

Thanks for such a quick reply.