On Thu, Dec 30, 2010 at 04:05:07AM -0600, Rob Landley wrote: > On 12/30/2010 03:44 AM, Kirill A. Shutemov wrote: > >>> If no rpcmount mountoption, no rpc_pipefs was found at > >>> '/var/lib/nfs/rpc_pipefs' and we are in init's mount namespace, we use > >>> init_rpc_pipefs. > >> > >> It's the "we are in init's mount namespace" that I was wondering about. > >> > >> So if I naievely chroot, nfs mount stops working the way it did before I > >> chrooted unless I do an extra setup step? > > > > No. It will work as before since you are still in init's mount namespace. > > Creating new mount namespace changes rules. > > Ah, CLONE_NEWNS and then you need /var/lib/nfs/rpc_pipefs. Got it. > > I'm kind of surprised that the kernel cares about a specific path under > /var/lib. (Seems like policy in the kernel somehow.) Yep. It's bad, but there is way to overwrite the default. Other way is to leave 'rpcmount' mountoption without default. get_rpc_pipefs(NULL) in init's mount namespace will always return init_rpc_pipefs, without filesystem lookup. get_rpc_pipefs(NULL) in non-init's mount namespace will always return error. So you will have to specify 'rpcmount' mountoption for every nfs mount in container. Hmm, I guess, it may confuse user. Or we can try to move the default to userspace. /sbin/mount.nfs? > Can't it just > check the current process's mount list to see if an instance of > rpc_pipefs is mounted in the current namespace the way lxc looks for > cgroups? Or are there potential performance/scalability issues with that? What should we do if we have several rpc_pipefs mounts in the namespace? -- Kirill A. Shutemov -- 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
