samba - Sep 2020 - Large Delays in Samba Responses

From time to time I get applications that use data on a Samba share 
locking up for long periods. Sometimes minutes.

I am using a Windows 10 client and Samba 4.12.5 on Fedora 32

smb.conf is pretty simple:

/[global]//
//?? log file = /var/log/samba/%m.log//
//?? writeable = yes//
//?? workgroup = HOME//
//?? hosts allow = 192.168.2.0/24 //
//?? security = user//
//?? passdb backend = tdbsam//
//?? unix extensions = no//
//?? load printers = no//
//?? wide links = yes//
//?? # trying disabling oplocks to see if that stops my hanging/delay 
problems//
//?? oplocks = no//
//?? socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 
SO_SNDBUF=65536 SO_KEEPALIVE//
//
//?? # needed for DDWRT routers//
//?? ntlm auth = yes/

with shares like:

/[minecraft]//
//??????? path = /opt/msm//
//??????? create mask = 0765//
//??????? comment = Minecraft/


Changing oplocks did not help.

I've done some packet captures and they all look similar to this one:

https://www.edcint.co.nz/tmp/samba_ss01.jpg

Here you can see long delays where nothing is happening on the network, 
and the server is not resource constrained. While this is happening 
applications that are trying to use files on the share lock up. In the 
screenshot shown, there was some operations on an "opencv" file which 
was not even open or being touched by the application that was hanging. 
In fact, it would have been days ago since I last used the file in a 
different application.

smbstatus at the time did not list this file at all.

I had this problem years ago and it just disappeared and it was fine for 
years, now it is back and don't know what it is.

Any ideas? Any troubleshooting steps I can take?



The raw packet capture is available here, if needed:

https://www.edcint.co.nz/tmp/win0b.snoop

On Tue, Sep 15, 2020 at 09:35:30AM +1000, Matthew Jurgens via samba
wrote:
> From time to time I get applications that use data on a Samba share locking
> up for long periods. Sometimes minutes.
> 
> I am using a Windows 10 client and Samba 4.12.5 on Fedora 32
> 
> smb.conf is pretty simple:
> 
> /[global]//
> //?? log file = /var/log/samba/%m.log//
> //?? writeable = yes//
> //?? workgroup = HOME//
> //?? hosts allow = 192.168.2.0/24 //
> //?? security = user//
> //?? passdb backend = tdbsam//
> //?? unix extensions = no//
> //?? load printers = no//
> //?? wide links = yes//
> //?? # trying disabling oplocks to see if that stops my hanging/delay
> problems//
> //?? oplocks = no//
> //?? socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536
> SO_SNDBUF=65536 SO_KEEPALIVE//
> //
> //?? # needed for DDWRT routers//
> //?? ntlm auth = yes/
> 
> with shares like:
> 
> /[minecraft]//
> //??????? path = /opt/msm//
> //??????? create mask = 0765//
> //??????? comment = Minecraft/
> 
> 
> Changing oplocks did not help.
> 
> I've done some packet captures and they all look similar to this one:
> 
> https://www.edcint.co.nz/tmp/samba_ss01.jpg
> 
> Here you can see long delays where nothing is happening on the network, and
> the server is not resource constrained. While this is happening
applications
> that are trying to use files on the share lock up. In the screenshot shown,
> there was some operations on an "opencv" file which was not even
open or
> being touched by the application that was hanging. In fact, it would have
> been days ago since I last used the file in a different application.
> 
> smbstatus at the time did not list this file at all.
> 
> I had this problem years ago and it just disappeared and it was fine for
> years, now it is back and don't know what it is.
> 
> Any ideas? Any troubleshooting steps I can take?
This is from a Windows client, yes ?

Do you, or have you ever had the Windows Microsoft provided NFS client
loaded on that client ?

On 16/09/2020 3:53 am, Jeremy Allison via samba wrote:
> On Tue, Sep 15, 2020 at 09:35:30AM +1000, Matthew Jurgens via samba wrote:
>>  From time to time I get applications that use data on a Samba share
locking
>> up for long periods. Sometimes minutes.
>>
>> I am using a Windows 10 client and Samba 4.12.5 on Fedora 32
>>
>>
> This is from a Windows client, yes ?
>
> Do you, or have you ever had the Windows Microsoft provided NFS client
> loaded on that client ?

I have never used any Windows NFS client