On Mon, 19 Jan 2026, Christian Brauner wrote: > On Mon, Jan 19, 2026 at 06:22:42PM +1100, NeilBrown wrote: > > On Mon, 19 Jan 2026, Christoph Hellwig wrote: > > > On Mon, Jan 19, 2026 at 10:23:13AM +1100, NeilBrown wrote: > > > > > This was Chuck's suggested name. His point was that STABLE means that > > > > > the FH's don't change during the lifetime of the file. > > > > > > > > > > I don't much care about the flag name, so if everyone likes PERSISTENT > > > > > better I'll roll with that. > > > > > > > > I don't like PERSISTENT. > > > > I'd rather call a spade a spade. > > > > > > > > EXPORT_OP_SUPPORTS_NFS_EXPORT > > > > or > > > > EXPORT_OP_NOT_NFS_COMPATIBLE > > > > > > > > The issue here is NFS export and indirection doesn't bring any benefits. > > > > > > No, it absolutely is not. And the whole concept of calling something > > > after the initial or main use is a recipe for a mess. > > > > We are calling it for it's only use. If there was ever another use, we > > could change the name if that made sense. It is not a public name, it > > is easy to change. > > > > > > > > Pick a name that conveys what the flag is about, and document those > > > semantics well. This flag is about the fact that for a given file, > > > as long as that file exists in the file system the handle is stable. > > > Both stable and persistent are suitable for that, nfs is everything > > > but. > > > > My understanding is that kernfs would not get the flag. > > kernfs filehandles do not change as long as the file exist. > > But this is not sufficient for the files to be usefully exported. > > > > I suspect kernfs does re-use filehandles relatively soon after the > > file/object has been destroyed. Maybe that is the real problem here: > > filehandle reuse, not filehandle stability. > > > > Jeff: could you please give details (and preserve them in future cover > > letters) of which filesystems are known to have problems and what > > exactly those problems are? > > > > > > > > Remember nfs also support volatile file handles, and other applications > > > might rely on this (I know of quite a few user space applications that > > > do, but they are kinda hardwired to xfs anyway). > > > > The NFS protocol supports volatile file handles. knfsd does not. > > So maybe > > EXPORT_OP_NOT_NFSD_COMPATIBLE > > might be better. or EXPORT_OP_NOT_LINUX_NFSD_COMPATIBLE. > > (I prefer opt-out rather than opt-in because nfsd export was the > > original purpose of export_operations, but it isn't something > > I would fight for) > > I prefer one of the variants you proposed here but I don't particularly > care. It's not a hill worth dying on. So if Christoph insists on the > other name then I say let's just go with it. >
This sounds like you are recommending that we give in to bullying. I would rather the decision be made based on the facts of the case, not the opinions that are stated most bluntly. I actually think that what Christoph wants is actually quite different from what Jeff wants, and maybe two flags are needed. But I don't yet have a clear understanding of what Christoph wants, so I cannot be sure. NeilBrown
