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.
