samba - May 2019 - FW: Weird Samba/CIFS behavior: client hangs

I think a network trace would tell us for use whether the server is
responding or not.

You can follow the instruction here to make one:

https://wiki.samba.org/index.php/Bug_Reporting#cifs.ko

-- 
Aurélien Aptel / SUSE Labs Samba Team
GPG: 1839 CB5F 9F5B FB9B AA97  8C99 03C8 A49B 521B D5D3
SUSE Linux GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg)

Ohhhh, thanks for the link to that kernel bug.

6 months ago or so, I ran into something similar which mostly manifested as
a periodic hang with high iowait times that would resolve itself in a half
hour or so.  This would mostly affect those who are constantly working off
of fileshares -- opening spreadsheets directly from the share, etc.

I eventually "resolved" by downgrading to a 4.9 kernel, and
haven't seen it
since (but haven't moved to newer kernels, either).  I thought it was a
kernel bug for sure, but never tied it directly to samba.  This is on
Debian, btw.

Also, from the most recent comment on that bug (
https://bugzilla.kernel.org/show_bug.cgi?id=198349#c42):

Note that if you are mounting with vers=1.0 (SMB1/CIFS) you will need
to either disable oplocks (see above) or use a recently proposed patch
from Ronnie to fix  credit handling for SMB1 oplocks.  The fix for
SMB1 oplock regression (which can cause hangs) will be in Linux kernel
5.2

Most people have disabled SMB1 by now, but I think that smbclient uses SMB1
by default.


Kris Lou
klou at themusiclink.net


On Fri, May 24, 2019 at 5:30 AM Aurélien Aptel via samba <
samba at lists.samba.org> wrote:
>
> I think a network trace would tell us for use whether the server is
> responding or not.
>
> You can follow the instruction here to make one:
>
> https://wiki.samba.org/index.php/Bug_Reporting#cifs.ko
>
> --
> Aurélien Aptel / SUSE Labs Samba Team
> GPG: 1839 CB5F 9F5B FB9B AA97  8C99 03C8 A49B 521B D5D3
> SUSE Linux GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
> GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg)
>
> --
> To unsubscribe from this list go to the following URL and read the
> instructions:  https://lists.samba.org/mailman/options/samba
>

> Most people have disabled SMB1 by now, but I think that smbclient uses
SMB1
> by default.
Yep it looks like oplocks was the problem.
I am still using SMB1 because it seems to best support POSIX extensions.
Any other version i've tried, seems to lose some feature.

Thank you

Gabriele

GPG Key Fingerprint:
DAD1 E3E3 C3E9 36FB C570 F405 9B5F 7108 A1D0 2FFF