[HN Gopher] KSMBD Declared Stable - No Longer "Experimental" - I...
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       KSMBD Declared Stable - No Longer "Experimental" - In Linux 6.6
        
       Author : LinuxBender
       Score  : 36 points
       Date   : 2023-09-10 17:53 UTC (5 hours ago)
        
 (HTM) web link (www.phoronix.com)
 (TXT) w3m dump (www.phoronix.com)
        
       | IshKebab wrote:
       | Wow this already had a security vulnerability from not handling
       | `..`. Not reassuring.
        
       | mariuolo wrote:
       | Perhaps it's obvious, but I'll ask anyway: what are the
       | advantages in moving this into kernel space?
       | 
       | Performance? Better integration with filesystems? Ease of use?
        
         | MuffinFlavored wrote:
         | Perhaps it's obvious but I'll ask the opposite: how large are
         | the possible negatives security wise for this?
        
       | fh973 wrote:
       | Apparently this is a Samsung project. Why does Samsung invest
       | resources in a project like this? They don't sell any storage
       | systems.
        
       | bombela wrote:
       | But wouldn't it better to find a way to run it in userland for
       | safety?
       | 
       | I know NFS was already part of the kernel. And I presume that by
       | living inside the kernel there is a tight integration with file
       | buffers/caching, and probably some extra performance too. Is that
       | the main motivation here?
        
       | YoshiRulz wrote:
       | Even if this is faster than Samba... the max. transfer speed will
       | be dictated by the client running Windows, surely.
        
         | londons_explore wrote:
         | RDMA tends to run at 100 Gbps rates and microseconds of
         | latency. In many cases, a data transfer can occur without the
         | CPU running much OS code at all - it's all done by the network
         | hardware DMA'ing the right memory from one machine, across the
         | network, and into the right place in RAM of another machine. It
         | is often faster than reading from local SSD.
         | 
         | One datacenter use is to find another machine on the network
         | who already has a file you want to load to RAM, and loading
         | that file across the network from them rather than reading the
         | file from your local SSD, simply because it is faster to do so.
        
       | bitwize wrote:
       | Remember when we used to make fun of _Windows_ for putting random
       | bullshit in the kernel  "for performance reasons"?
       | 
       | And then they stopped doing that. Because it was stupid.
        
         | ZiiS wrote:
         | I hope this is mainly for running on your router; the efficency
         | gains still matter there and it is single purpose enough that
         | you would primarally be concerned with whatevere implemented
         | the server.
         | 
         | Having it listening on a workstation containing sensative
         | information I would much prefer an older more isolatable
         | userapace implementation.
        
       | londons_explore wrote:
       | I'm kinda of the opinion that things listening on the network
       | shouldn't be in-kernel.
       | 
       | Instead, the kernel interfaces should be improved to allow
       | userspace applications to get the same performance benefits. For
       | example, RDMA could be arranged from userspace by having a
       | sendfile() like syscall suitable for telling the kernel that RDMA
       | requests should be satisfied from a certain file handle. Perhaps
       | even seccomp bpf could be used for constructing more complex
       | response packets without needing a context switch to the
       | userspace application.
        
         | tadfisher wrote:
         | io_uring already supports zero-copy networking (it's basically
         | an RDMA API after all), and I believe the latest versions of
         | Samba use it to great effect. I'm pretty confident this server
         | could be ported entirely to userspace and maybe even get better
         | performance by avoiding the userspace listener for DCE/RPC.
        
         | AshamedCaptain wrote:
         | You know the real reason behind this was to get a GPL2'd Samba
         | that (other) people would be forced to support, right?
         | 
         | Plenty hw manufacturers still won't touch the GPLv3 Samba with
         | a ten-foot pole but do not want to commit to support a fork
         | themselves with all the CVEs it would entail over the years. By
         | putting it in the kernel where it'll have high visibility and
         | with some excuse about performance requirements, at least
         | someone may take the bait later on and maintain this one for
         | free. May even become more popular than Samba itself. Win win!
        
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       (page generated 2023-09-10 23:02 UTC)