sunrpc: create a new dummy pipe for gssd to hold open

rpc.gssd will naturally hold open any pipe named */clnt*/gssd that shows
up under rpc_pipefs. That behavior gives us a reliable mechanism to tell
whether it's actually running or not.

Create a new toplevel "gssd" directory in rpc_pipefs when it's mounted.
Under that directory create another directory called "clntXX", and then
within that a pipe called "gssd".

We'll never send an upcall along that pipe, and any downcall written to
it will just return -EINVAL.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/sunrpc/netns.h b/net/sunrpc/netns.h
index 779742cfc1ff..8a8e841d1547 100644
--- a/net/sunrpc/netns.h
+++ b/net/sunrpc/netns.h
@@ -14,6 +14,7 @@ struct sunrpc_net {
 	struct cache_detail *rsi_cache;
 
 	struct super_block *pipefs_sb;
+	struct rpc_pipe *gssd_dummy;
 	struct mutex pipefs_sb_lock;
 
 	struct list_head all_clients;