On Thu, Jan 15, 2026 at 09:14:06AM +0100, Christian Brauner wrote: > On Wed, Jan 14, 2026 at 10:42:48PM -0800, Christoph Hellwig wrote: > > On Wed, Jan 14, 2026 at 04:20:13PM +0100, Christian Brauner wrote: > > > > You're still think of it the wrong way. If we do have file systems > > > > that break the original exportfs semantics we need to fix that, and > > > > something like a "stable handles" flag will work well for that. But > > > > a totally arbitrary "is exportable" flag is total nonsense. > > > > > > File handles can legitimately be conceptualized independently of > > > exporting a filesystem. If we wanted to tear those concepts apart > > > implementation wise we could. > > > > > > It is complete nonsense to expect the kernel to support exporting any > > > arbitrary internal filesystem or to not support file handles at all. > > > > You are going even further down the path of entirely missing the point > > (or the two points by now). > > You're arguing for the sake of arguing imho. You're getting exactly what > we're all saying as evidenced by the last paragraph in your mail: it is > entirely what this whole thing is about.
I can't even parse what you mean. And no, I hate these stupid arguments, and I have much better things to do than dragging this on. > > If a file systems meets all technical requirements of being nfsd > > exportable and the users asks for it, it is not our job to make an > > arbitrary policy decision to say no. > > This is an entirely irrelevant point because we're talking about > cgroupfs, nsfs, and pidfs. And they don't meet this criteria. cgroupfs > is a _local resource management filesystem_ why would we ever want to > support exporting it over the network. It allows to break the local > delegation model as I've explained. cgroupfs shows _local processes_. So > a server will see completely nonsensical PID identifiers listed in > cgroup files and it can fsck around with processes in a remote system. None of that is a technical argument. The lack of stable file handles would be one, and I think we came to the conclusion yesterday that this is the case.
