NFS: Return an error when starting the idmapping pipe

Return an error when starting the idmapping pipe so that we can detect it
failing.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/idmap.c

@@ -108,24 +108,27 @@ static struct rpc_pipe_ops idmap_upcall_ops = {
         .destroy_msg    = idmap_pipe_destroy_msg,
 };
 
-void
+int
 nfs_idmap_new(struct nfs_client *clp)
 {
 	struct idmap *idmap;
+	int error;
 
 	if (clp->cl_idmap != NULL)
-		return;
+		return 0;
+
         if ((idmap = kzalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
-                return;
+                return -ENOMEM;
 
 	snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
 	    "%s/idmap", clp->cl_rpcclient->cl_pathname);
 
         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
 	    idmap, &idmap_upcall_ops, 0);
         if (IS_ERR(idmap->idmap_dentry)) {
+		error = PTR_ERR(idmap->idmap_dentry);
 		kfree(idmap);
-		return;
+		return error;
 	}
 
         mutex_init(&idmap->idmap_lock);
@@ -135,6 +138,7 @@ nfs_idmap_new(struct nfs_client *clp)
 	idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
 
 	clp->cl_idmap = idmap;
+	return 0;
 }
 
 void

fs/nfs/super.c

@@ -1136,7 +1136,8 @@ static struct rpc_clnt *nfs4_create_client(struct nfs_server *server,
 		clnt->cl_softrtry = 1;
 		clp->cl_rpcclient = clnt;
 		memcpy(clp->cl_ipaddr, server->ip_addr, sizeof(clp->cl_ipaddr));
-		nfs_idmap_new(clp);
+		if (nfs_idmap_new(clp) < 0)
+			goto out_fail;
 	}
 	list_add_tail(&server->nfs4_siblings, &clp->cl_superblocks);
 	clnt = rpc_clone_client(clp->cl_rpcclient);

include/linux/nfs_idmap.h

@@ -64,7 +64,7 @@ struct idmap_msg {
 /* Forward declaration to make this header independent of others */
 struct nfs_client;
 
-void nfs_idmap_new(struct nfs_client *);
+int nfs_idmap_new(struct nfs_client *);
 void nfs_idmap_delete(struct nfs_client *);
 
 int nfs_map_name_to_uid(struct nfs_client *, const char *, size_t, __u32 *);