SUNRPC: subscribe RPC clients to pipefs notifications

This patch subscribes RPC clients to RPC pipefs notifications. RPC clients
notifier block is registering with pipefs initialization during SUNRPC module
init.
This notifier callback is responsible for RPC client PipeFS directory and GSS
pipes creation. For pipes creation and destruction two additional callbacks
were added to struct rpc_authops.
Note that no locking required in notifier callback because PipeFS superblock
pointer is passed as an argument from it's creation or destruction routine and
thus we can be sure about it's validity.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 1a6fa9173519..9da2d837b512 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -762,8 +762,10 @@ static void gss_pipes_dentries_destroy(struct rpc_auth *auth)
         struct gss_auth *gss_auth;
 
         gss_auth = container_of(auth, struct gss_auth, rpc_auth);
-        rpc_unlink(gss_auth->pipe[0]->dentry);
-        rpc_unlink(gss_auth->pipe[1]->dentry);
+        if (gss_auth->pipe[0]->dentry)
+                rpc_unlink(gss_auth->pipe[0]->dentry);
+        if (gss_auth->pipe[1]->dentry)
+                rpc_unlink(gss_auth->pipe[1]->dentry);
 }
 
 static int gss_pipes_dentries_create(struct rpc_auth *auth)
@@ -1614,7 +1616,9 @@ static const struct rpc_authops authgss_ops = {
         .create         = gss_create,
         .destroy        = gss_destroy,
         .lookup_cred    = gss_lookup_cred,
-        .crcreate       = gss_create_cred
+        .crcreate       = gss_create_cred,
+        .pipes_create   = gss_pipes_dentries_create,
+        .pipes_destroy  = gss_pipes_dentries_destroy,
 };
 
 static const struct rpc_credops gss_credops = {