On Fri, Jan 14, 2022 at 03:57:03PM +0000, Chris Chilvers wrote: > > I'm probably just reading too quickly, but I'm not seeing how this > > explains the problems with your original configuration. > > > > Is it that /sr/nfs/bin on you system is a symlink? (And what exactly is > > the content of that symlink?) > > No, all the directories under /srv/nfs are ordinary directories. The symlinks > are in the root of the real file system. Oh, got it, thanks for the explanation. > So I have: > /bin -> /usr/bin > /software -> /usr/lib (created to test the hypothesis) > /srv/nfs/ > /srv/nfs/assets > /srv/nfs/bin > /srv/nfs/software > > Because exportfs is not taking into account the rootdir setting, when it tries > to resolve the path from /etc/exports, it sees the path /bin, and matches that > with the real /bin, and resolves it to /usr/bin. > > Later exportfs errors when trying to resolve the real path (e_realpath) in the > exportent_mkrealpath function, as this function does prepend the rootdir. This > causes exportfs to look for /srv/nfs/usr/bin instead of the expected > /srv/nfs/bin. > > At best this causes an error, but if that does happen to match an existing path > under /srv/nfs then it would export the wrong directory. > > This will happen for any export that happens to match an existing symlink. > > There are two issues though that I'm not sure how best to handle: > * Should the symlink be considered relative to the local system or relative to > the rootdir? > * What happens if the symlink points to a directory outside the rootdir? Yes, I'm not sure off hand what the right behavior is, but the existing behavior certainly seems to violate the principal of least surprise. --b. > > In my case I think the symlink would need to be resolved relative to the > rootdir. This is because we're re-exporting an existing NFS server, so if the > existing NFS server is exporting some kind of symlink tree, the symlinks would > be relative to the existing mounts. > > One option that would be valid for my case would be an setting to disable > symlink resolution and just consider it an error if an export is a symlink. > Since I'm re-exporting an existing NFS server, they can't be symlinks anyway. > > -- Chris
