On Tue, 2009-01-06 at 15:58 -0600, Serge E. Hallyn wrote: > Quoting Trond Myklebust (trond.myklebust@xxxxxxxxxx): > > On Tue, 2009-01-06 at 14:02 -0600, Serge E. Hallyn wrote: > > > Quoting Matt Helsley (matthltc@xxxxxxxxxx): > > > > We can often specify the UTS namespace to use when starting an RPC client. > > > > However sometimes no UTS namespace is available (specifically during system > > > > shutdown as the last NFS mount in a container is unmounted) so fall > > > > back to the initial UTS namespace. > > > > > > So what happens if we take this patch and do nothing else? > > > > > > The only potential problem situation will be rpc requests > > > made on behalf of a container in which the last task has > > > exited, right? So let's say a container did an nfs mount > > > and then exits, causing an nfs umount request. > > > > > > That umount request will now be sent with the wrong nodename. > > > Does that actually cause problems, will the server use the > > > nodename to try and determine the client sending the request? > > > > The NFSv2/v3 umount rpc call will be sent by the 'umount' program from > > userspace, not the kernel. The problem here is that because lazy mounts > > exist, the lifetime of the RPC client may be longer than that of the > > Right that was what i was referring to. > > > container. In addition, it may be shared among more than 1 container, > > because superblocks can be shared. > > Good point. And in that case what do we care about (even though > apparently we just might not care at all :) - who did the mount, > or who is using it? > > In fact one thing I noticed in Matt's patch 3 was that he copied > in the nodename verbatim, so a future hostname() by the container > wouldn't be reflected, again not sure if that would matter. I thought of this. I found the patches that added the nodename in the RPC client struct and the stale nodename was intentional. That's why I preserved the copy rather than called utsname() each time. Cheers, -Matt -- 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
