NFS: handle NFS idmap pipe PipeFS dentries by network namespace aware routines

This patch makes NFS idmap pipes dentries allocated and destroyed in network
namespace context by PipeFS network namespace aware routines.
Network namespace context is obtained from nfs_client structure.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/idmap.c

@@ -431,6 +431,56 @@ static const struct rpc_pipe_ops idmap_upcall_ops = {
 	.destroy_msg	= idmap_pipe_destroy_msg,
 };
 
+static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
+{
+	if (pipe->dentry)
+		rpc_unlink(pipe->dentry);
+}
+
+static int __nfs_idmap_register(struct dentry *dir,
+				     struct idmap *idmap,
+				     struct rpc_pipe *pipe)
+{
+	struct dentry *dentry;
+
+	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+	pipe->dentry = dentry;
+	return 0;
+}
+
+static void nfs_idmap_unregister(struct nfs_client *clp,
+				      struct rpc_pipe *pipe)
+{
+	struct net *net = clp->net;
+	struct super_block *pipefs_sb;
+
+	pipefs_sb = rpc_get_sb_net(net);
+	if (pipefs_sb) {
+		__nfs_idmap_unregister(pipe);
+		rpc_put_sb_net(net);
+	}
+}
+
+static int nfs_idmap_register(struct nfs_client *clp,
+				   struct idmap *idmap,
+				   struct rpc_pipe *pipe)
+{
+	struct net *net = clp->net;
+	struct super_block *pipefs_sb;
+	int err = 0;
+
+	pipefs_sb = rpc_get_sb_net(net);
+	if (pipefs_sb) {
+		if (clp->cl_rpcclient->cl_dentry)
+			err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
+						   idmap, pipe);
+		rpc_put_sb_net(net);
+	}
+	return err;
+}
+
 int
 nfs_idmap_new(struct nfs_client *clp)
 {
@@ -450,12 +500,8 @@ nfs_idmap_new(struct nfs_client *clp)
 		kfree(idmap);
 		return error;
 	}
-
-	if (clp->cl_rpcclient->cl_dentry)
-		pipe->dentry = rpc_mkpipe_dentry(clp->cl_rpcclient->cl_dentry,
-				"idmap", idmap, pipe);
-	if (IS_ERR(pipe->dentry)) {
-		error = PTR_ERR(pipe->dentry);
+	error = nfs_idmap_register(clp, idmap, pipe);
+	if (error) {
 		rpc_destroy_pipe_data(pipe);
 		kfree(idmap);
 		return error;
@@ -478,8 +524,7 @@ nfs_idmap_delete(struct nfs_client *clp)
 
 	if (!idmap)
 		return;
-	if (idmap->idmap_pipe->dentry)
-		rpc_unlink(idmap->idmap_pipe->dentry);
+	nfs_idmap_unregister(clp, idmap->idmap_pipe);
 	rpc_destroy_pipe_data(idmap->idmap_pipe);
 	clp->cl_idmap = NULL;
 	kfree(idmap);