On 7/14/25 6:36 AM, Aurélien Couderc wrote: > On Sun, Jul 13, 2025 at 7:50 PM Chuck Lever <cel@xxxxxxxxxx> wrote: >> Also the request for "training material" for individual NFSv4.2 >> operations does not make sense. We do not have training material for >> the NFSv3 READDIRPLUS procedure, for example. >> >> Therefore I ignored the email. > > OK, but as an analog: SMB is infamous for "too many" features, all > which can cause trouble. Over time SAMBA added controls to turn > features on/off or use different ways of emulation. Samba has to navigate between two rather incompatible worlds: POSIX as it is implemented on Linux and FreeBSD, and the Windows world, via a non-POSIX network file protocol (SMB). There needs to be some flexibility of configuration there. > So far NFSv4.2 has > no controls to turn specific features on/off, or even get statistics, > or put limits on certain features. There has to be a demonstrated need for each such control. We're not going to add controls that don't have any real use because controls actually have a long-term cost. One or two might not be expensive to maintain, but when you add them with abandon, it adds up: - Administrative complexity increases - Our test matrix increases exponentially - The documentation workload increases - Kernel API rules make it difficult to fix mistakes or remove deprecated controls - Replacing a constant with a control setting has a small run-time cost - Developing around these controls can sometimes be difficult There are very good reasons why Gnome removed most of their configuration settings a few years back. Eventually it becomes impossible to manage and maintain the software. This is not to say we won't add a control if it should become necessary. So do you have a need to disable an NFSv4.2 feature? If so, which ones, and why? Do you have a need to limit some feature? If so, why? What operations and events do you want to count? Why? Why can't you use eBPF, kprobes, Dtrace, systemtap ? Since this is open source, can you contribute what you need rather than asking us to implement it? > That IS a problem, which SAMBA and even Windows Server SMB have > solved. Otherwise you're at the mercy of whatever combination of NFS > client and NFS server you have, and that is NOT good. That is still a very generic complaint. If you have a specific issue or question, please post it. Simply saying "we need more controls" is just not actionable. -- Chuck Lever
