nfsd: Fix nfsd leaks sunrpc module references

Stefan Hajnoczi reports,
nfsd leaks 3 references to the sunrpc module here:

  # echo -n "asdf 1234" >/proc/fs/nfsd/portlist
  bash: echo: write error: Protocol not supported

Now stop nfsd and try unloading the kernel modules:

  # systemctl stop nfs-server
  # systemctl stop nfs
  # systemctl stop proc-fs-nfsd.mount
  # systemctl stop var-lib-nfs-rpc_pipefs.mount
  # rmmod nfsd
  # rmmod nfs_acl
  # rmmod lockd
  # rmmod auth_rpcgss
  # rmmod sunrpc
  rmmod: ERROR: Module sunrpc is in use
  # lsmod | grep rpc
  sunrpc                315392  3

It is caused by nfsd don't cleanup rpcb program for nfsd
when destroying svc service after creating xprt fail.

Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 3779a5fbeb42..45007acaf364 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -378,14 +378,13 @@ static void nfsd_last_thread(struct svc_serv *serv, struct net *net)
          * write_ports can create the server without actually starting
          * any threads--if we get shut down before any threads are
          * started, then nfsd_last_thread will be run before any of this
-         * other initialization has been done.
+         * other initialization has been done except the rpcb information.
          */
+        svc_rpcb_cleanup(serv, net);
         if (!nn->nfsd_net_up)
                 return;
-        nfsd_shutdown_net(net);
-
-        svc_rpcb_cleanup(serv, net);
 
+        nfsd_shutdown_net(net);
         printk(KERN_WARNING "nfsd: last server has exited, flushing export "
                             "cache\n");
         nfsd_export_flush(net);