lkml.org 
[lkml]   [2021]   [Apr]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2 00/10] cifsd: introduce new SMB3 kernel server
From
On Thu, Apr 22, 2021 at 09:28:14AM +0900, Namjae Jeon wrote:
> This is the patch series for cifsd(ksmbd) kernel server.
>
> What is cifsd(ksmbd) ?
> ======================
>
> The SMB family of protocols is the most widely deployed
> network filesystem protocol, the default on Windows and Macs (and even
> on many phones and tablets), with clients and servers on all major
> operating systems, but lacked a kernel server for Linux. For many
> cases the current userspace server choices were suboptimal
> either due to memory footprint, performance or difficulty integrating
> well with advanced Linux features.
>
> ksmbd is a new kernel module which implements the server-side of the SMB3 protocol.
> The target is to provide optimized performance, GPLv2 SMB server, better
> lease handling (distributed caching). The bigger goal is to add new
> features more rapidly (e.g. RDMA aka "smbdirect", and recent encryption
> and signing improvements to the protocol) which are easier to develop
> on a smaller, more tightly optimized kernel server than for example
> in Samba. The Samba project is much broader in scope (tools, security services,
> LDAP, Active Directory Domain Controller, and a cross platform file server
> for a wider variety of purposes) but the user space file server portion
> of Samba has proved hard to optimize for some Linux workloads, including
> for smaller devices. This is not meant to replace Samba, but rather be
> an extension to allow better optimizing for Linux, and will continue to
> integrate well with Samba user space tools and libraries where appropriate.
> Working with the Samba team we have already made sure that the configuration
> files and xattrs are in a compatible format between the kernel and
> user space server.
>
>
> Architecture
> ============
>
> |--- ...
> --------|--- ksmbd/3 - Client 3
> |-------|--- ksmbd/2 - Client 2
> | | ____________________________________________________
> | | |- Client 1 |
> <--- Socket ---|--- ksmbd/1 <<= Authentication : NTLM/NTLM2, Kerberos |
> | | | | <<= SMB engine : SMB2, SMB2.1, SMB3, SMB3.0.2, |
> | | | | SMB3.1.1 |
> | | | |____________________________________________________|
> | | |
> | | |--- VFS --- Local Filesystem
> | |
> KERNEL |--- ksmbd/0(forker kthread)
> ---------------||---------------------------------------------------------------
> USER ||
> || communication using NETLINK
> || ______________________________________________
> || | |
> ksmbd.mountd <<= DCE/RPC(srvsvc, wkssvc, samr, lsarpc) |
> ^ | <<= configure shares setting, user accounts |
> | |______________________________________________|
> |
> |------ smb.conf(config file)
> |
> |------ ksmbdpwd.db(user account/password file)
> ^
> ksmbd.adduser ---------------|
>
> The subset of performance related operations(open/read/write/close etc.) belong
> in kernelspace(ksmbd) and the other subset which belong to operations(DCE/RPC,
> user account/share database) which are not really related with performance are
> handled in userspace(ksmbd.mountd).
>
> When the ksmbd.mountd is started, It starts up a forker thread at initialization
> time and opens a dedicated port 445 for listening to SMB requests. Whenever new
> clients make request, Forker thread will accept the client connection and fork
> a new thread for dedicated communication channel between the client and
> the server.

Judging from the diagram above, all those threads are kernel threads, is
that right? So a kernel thread gets each call first, then uses netlink
to get help from ksmbd.mountd if necessary, is that right?

--b.

\
 
 \ /
  Last update: 2021-04-27 22:54    [W:0.135 / U:2.940 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site