What a smbc_new_context timeout does and is there a way to change it?

[Andreas Schneider]

On Tuesday 15 December 2015 11:05:41 Jeremy Allison wrote:
> On Wed, Dec 09, 2015 at 03:08:52PM +0100, Vladimir Marek wrote:
> > Hi,
> > 
> > we have a customer who reports that sometimes his smbget processes fail
> > with error message:
> > 
> > Can't read 32768000 bytes at offset 7700480000, file smb://...
> > 
> > 
> > I have traced it to a timeout in smbc_free_context in
> > source3/libsmb/libsmb_context.c
> > 
> > 
> > smbc_new_context(void)
> > {
> > ...
> > smbc_setTimeout(context, 20000);
> > ...
> > 
> > 
> > This happens for samba 3.6, but I believe that the same code is used in
> > samba 4.
> > 
> > 
> > If I increase the timeout the problems with smbget go away.
> > 
> > I would like to ask for help
> > 
> > a) what is this timeout doing?
> > I have suspicion that it's related to network operations and since
> > customer is transferring huge amounts of data the network might be
> > saturated.
> 
> Yes, it times out the connection after that number of msec.
> 
> > b) Is there a way to modify this timeout without touching the code, ie.
> > from configuration file? I haven't been able to find a way - I believe
> > it's set to be 20 seconds.
> 
> No, you'll need to modify the code.
> 
> > c) If we accept that the way to fix the problem is to increase the
> > timeout, what would be the preferred way to do it? Just increase the
> > number? Make it configurable? I don't know how difficult is to add
> > configuration variable.
> 
> I would add a command line parameter, say '-t timeout' (in seconds)
> to smbget, then just pass that into smbc_setTimeout().
> 
> Jeremy.

I've started to rewrite several parts of smbget as it is broken in several 
ways. I could add that option. However patches are welcome.



	-- andreas

-- 
Andreas Schneider                   GPG-ID: CC014E3D
Samba Team                             asn at samba.org
www.samba.org