CIFS backporting for kernel 2.6, SMB2/3 dialect support

CIFS backporting for kernel 2.6, SMB2/3 dialect support

[Chris Davies]

Hi folks, I'm hoping to achieve SMB2.0+ dialect support for CentOS 6 clients (currently with CIFS 1.68).  Has anyone done a backport of newer CIFS versions for use in production? Was it trivial?

Thanks,

CHRIS DAVIES
Umedia VFX & Finishing
www.umedia.eu BRUSSELS | LONDON | LOS ANGELES | PARIS | VANCOUVER 

Re: CIFS backporting for kernel 2.6, SMB2/3 dialect support

[Aurélien Aptel]

Hi Chris,

Chris Davies <chris.davies-fcHNbCilqsSHXe+LvDLADg@public.gmane.org> writes:
> Hi folks, I'm hoping to achieve SMB2.0+ dialect support for CentOS 6 clients (currently with CIFS 1.68).  Has anyone done a backport of newer CIFS versions for use in production? Was it trivial?

According to wikipedia CenOS 6 is based on kernel 2.6.32. This is
*old*. Adding SMBv2 support required large refactoring efforts and
kernel APIs are often changing so I expect backporting to be very hard
unfortunately.

Cheers,

-- 
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, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)

Re: CIFS backporting for kernel 2.6, SMB2/3 dialect support

[ronnie sahlberg]

Concur with  Aurélien.

2.6.32 is VERY old and there are several core kernel APIs that have
changed significantly between 2.6 and current kernels.
For example the whole iovector API for how buffers are handled changed
dramatically. And there are other dramatic API  changes too.

As a lot of distros do ship "old-ish" (but not as old as 2.6) kernels
but with modern CIFS, it is not impossible but it is far far from
being trivial.
Especially since 2.6.32 is so old that you will have to write a whole
bunch of translation wrappers to accomodate the
kernel API changes that cifs.ko need to interface to.


Unless you are willing to dedicate resources to a big port, and
continued support,
It is possible but will require significant effort and likely
significant cost, both to backport it as well as supporting it.
I would just stick with 2.6.32 and SMB1 for now until you get to the
point where you can upgrade the whole distro/kernel to a more recent
varient.



regards
ronnie sahlberg


On Thu, Oct 19, 2017 at 7:09 PM, Aurélien Aptel <aaptel-IBi9RG/b67k@public.gmane.org> wrote:
> Hi Chris,
>
> Chris Davies <chris.davies-fcHNbCilqsSHXe+LvDLADg@public.gmane.org> writes:
>> Hi folks, I'm hoping to achieve SMB2.0+ dialect support for CentOS 6 clients (currently with CIFS 1.68).  Has anyone done a backport of newer CIFS versions for use in production? Was it trivial?
>
> According to wikipedia CenOS 6 is based on kernel 2.6.32. This is
> *old*. Adding SMBv2 support required large refactoring efforts and
> kernel APIs are often changing so I expect backporting to be very hard
> unfortunately.
>
> Cheers,
>
> --
> 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, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

RE: CIFS backporting for kernel 2.6, SMB2/3 dialect support

[Chris Davies]

Thank you both very much for the advice and direction on this. Avoiding the research and effort we might have spent on this dubious task is invaluable!


-Chris

-----Original Message-----
From: ronnie sahlberg [mailto:ronniesahlberg@gmail.com] 
Sent: October 19, 2017 2:50 AM
To: Aurélien Aptel <aaptel@suse.com>
Cc: Chris Davies <chris.davies@umedia.eu>; linux-cifs@vger.kernel.org
Subject: Re: CIFS backporting for kernel 2.6, SMB2/3 dialect support

Concur with  Aurélien.

2.6.32 is VERY old and there are several core kernel APIs that have changed significantly between 2.6 and current kernels.
For example the whole iovector API for how buffers are handled changed dramatically. And there are other dramatic API  changes too.

As a lot of distros do ship "old-ish" (but not as old as 2.6) kernels but with modern CIFS, it is not impossible but it is far far from being trivial.
Especially since 2.6.32 is so old that you will have to write a whole bunch of translation wrappers to accomodate the kernel API changes that cifs.ko need to interface to.


Unless you are willing to dedicate resources to a big port, and continued support, It is possible but will require significant effort and likely significant cost, both to backport it as well as supporting it.
I would just stick with 2.6.32 and SMB1 for now until you get to the point where you can upgrade the whole distro/kernel to a more recent varient.



regards
ronnie sahlberg


On Thu, Oct 19, 2017 at 7:09 PM, Aurélien Aptel <aaptel@suse.com> wrote:
> Hi Chris,
>
> Chris Davies <chris.davies@umedia.eu> writes:
>> Hi folks, I'm hoping to achieve SMB2.0+ dialect support for CentOS 6 clients (currently with CIFS 1.68).  Has anyone done a backport of newer CIFS versions for use in production? Was it trivial?
>
> According to wikipedia CenOS 6 is based on kernel 2.6.32. This is 
> *old*. Adding SMBv2 support required large refactoring efforts and 
> kernel APIs are often changing so I expect backporting to be very hard 
> unfortunately.
>
> Cheers,
>
> --
> 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, Jane Smithard, Graham Norton, HRB 21284 (AG 
> Nürnberg)
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" 
> in the body of a message to majordomo@vger.kernel.org More majordomo 
> info at  http://vger.kernel.org/majordomo-info.html