> On Jan 25, 2024, at 5:44 PM, NeilBrown <neilb@xxxxxxx> wrote: > > On Thu, 25 Jan 2024, Chuck Lever III wrote: >> >> >>> On Jan 24, 2024, at 6:24 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: >>> >>> On Wed, 2024-01-24 at 10:52 +0100, Lorenzo Bianconi wrote: >>>> [...] >>>>> >>>>> That's a great question. We do need to properly support the -H option to >>>>> rpc.nfsd. What we do today is look up the hostname or address using >>>>> getaddrinfo, and then open a listening socket for that address and then >>>>> pass that fd down to the kernel, which I think then takes the socket and >>>>> sticks it on sv_permsocks. >>>>> >>>>> All of that seems a bit klunky. Ideally, I'd say the best thing would be >>>>> to allow userland to pass the sockaddr we look up directly via netlink, >>>>> and then let the kernel open the socket. That will probably mean >>>>> refactoring some of the svc_xprt_create machinery to take a sockaddr, >>>>> but I don't think it looks too hard to do. >>>> >>>> Do we already have a specific use case for it? I think we can even add it >>>> later when we have a defined use case for it on top of the current series. >>>> >>> >>> Yes: >>> >>> rpc.nfsd -H makes nfsd listen on a particular address and port. By >>> passing down the sockaddr instead of an already-opened socket >>> descriptor, we can achieve the goal without having to open sockets in >>> userland. >> >> Tearing down a listener that was created that way would be a >> use case for: > > Only if it was actually useful. > Have you *ever* wanted to do that? Or heard from anyone else who did? Another possibility is removing a listener when unplugging a network device. That also might be automatic already. But hey, we don't have this kind of administrative capability today, so there's no need to add it in a first pass of this new interface either. I'm happy to wait and see. >>> Do we ever want/need to remove listening sockets? >>> Normal practice when making any changes is to stop and restart where >>> "stop" removes all sockets, unexports all filesystems, disables all >>> versions. -- Chuck Lever
