On Wed, Jul 13, 2016 at 05:06:34PM +0200, Nikolaus Rath wrote: > On Jul 12 2016, Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote: > > In NFSv4, offsets 1 and 2 are reserved: > > https://tools.ietf.org/html/rfc7530#section-16.24 > > Ah, that explains it. Thanks! > > I was assuming that I could export any "proper" unix file system over > NFS - and as far as I know, the rest of the VFS does not make any > assumptions (or reservations) about readdir offsets. Are there other > such constraints? I looked at the RFC, but it's rather hard to extract > that specific information... Local filesystems only need to generate readdir offsets that work for a given open, while exportable filesystem need to readdir offsets that they can still interpret at an arbitrary future point (possibly after a reboot). The other main requirements are on filehandles. An in-kernel filesystem shouldn't define export_ops if it doesn't support export, so should be able to fail export attempts early on rather than seeming to work and then behaving weird later, as in this case. I don't know if there's a comparable way for a fuse filesystem to say "don't even try exporting me". --b. > > Best, > Nikolaus > > -- > GPG encrypted emails preferred. Key id: 0xD113FCAC3C4E599F > Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F > > »Time flies like an arrow, fruit flies like a Banana.« > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
