[PATCH] RPC: [PATCH] improve rpcauthauth_create error returns

 Currently we return -ENOMEM for every single failure to create a new auth.
 This is actually accurate for auth_null and auth_unix, but for auth_gss it's a
 bit confusing.

 Allow rpcauth_create (and the ->create methods) to return errors.  With this
 patch, the user may sometimes see an EINVAL instead.  Whee.

 Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/inode.c

@@ -160,11 +160,10 @@ nfs_clear_inode(struct inode *inode)
 void
 nfs_umount_begin(struct super_block *sb)
 {
-	struct nfs_server *server = NFS_SB(sb);
-	struct rpc_clnt	*rpc;
+	struct rpc_clnt	*rpc = NFS_SB(sb)->client;
 
 	/* -EIO all pending I/O */
-	if ((rpc = server->client) != NULL)
+	if (!IS_ERR(rpc))
 		rpc_killall_tasks(rpc);
 }
 
@@ -450,11 +449,14 @@ nfs_fill_super(struct super_block *sb, struct nfs_mount_data *data, int silent)
 		return PTR_ERR(server->client);
 	/* RFC 2623, sec 2.3.2 */
 	if (authflavor != RPC_AUTH_UNIX) {
+		struct rpc_auth *auth;
+
 		server->client_sys = rpc_clone_client(server->client);
 		if (IS_ERR(server->client_sys))
 			return PTR_ERR(server->client_sys);
-		if (!rpcauth_create(RPC_AUTH_UNIX, server->client_sys))
-			return -ENOMEM;
+		auth = rpcauth_create(RPC_AUTH_UNIX, server->client_sys);
+		if (IS_ERR(auth))
+			return PTR_ERR(auth);
 	} else {
 		atomic_inc(&server->client->cl_count);
 		server->client_sys = server->client;
@@ -1450,6 +1452,7 @@ static struct super_block *nfs_get_sb(struct file_system_type *fs_type,
 	memset(server, 0, sizeof(struct nfs_server));
 	/* Zero out the NFS state stuff */
 	init_nfsv4_state(server);
+	server->client = server->client_sys = ERR_PTR(-EINVAL);
 
 	root = &server->fh;
 	if (data->flags & NFS_MOUNT_VER3)
@@ -1506,9 +1509,9 @@ static void nfs_kill_super(struct super_block *s)
 
 	kill_anon_super(s);
 
-	if (server->client != NULL && !IS_ERR(server->client))
+	if (!IS_ERR(server->client))
 		rpc_shutdown_client(server->client);
-	if (server->client_sys != NULL && !IS_ERR(server->client_sys))
+	if (!IS_ERR(server->client_sys))
 		rpc_shutdown_client(server->client_sys);
 
 	if (!(server->flags & NFS_MOUNT_NONLM))
@@ -1650,7 +1653,7 @@ static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data,
 	}
 
 	down_write(&clp->cl_sem);
-	if (clp->cl_rpcclient == NULL) {
+	if (IS_ERR(clp->cl_rpcclient)) {
 		xprt = xprt_create_proto(proto, &server->addr, &timeparms);
 		if (IS_ERR(xprt)) {
 			up_write(&clp->cl_sem);
@@ -1711,9 +1714,12 @@ static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data,
 	}
 
 	if (clnt->cl_auth->au_flavor != authflavour) {
-		if (rpcauth_create(authflavour, clnt) == NULL) {
+		struct rpc_auth *auth;
+
+		auth = rpcauth_create(authflavour, clnt);
+		if (IS_ERR(auth)) {
 			dprintk("%s: couldn't create credcache!\n", __FUNCTION__);
-			return -ENOMEM;
+			return PTR_ERR(auth);
 		}
 	}
 
@@ -1788,6 +1794,7 @@ static struct super_block *nfs4_get_sb(struct file_system_type *fs_type,
 	memset(server, 0, sizeof(struct nfs_server));
 	/* Zero out the NFS state stuff */
 	init_nfsv4_state(server);
+	server->client = server->client_sys = ERR_PTR(-EINVAL);
 
 	p = nfs_copy_user_string(NULL, &data->hostname, 256);
 	if (IS_ERR(p))

fs/nfs/nfs4state.c

@@ -110,6 +110,7 @@ nfs4_alloc_client(struct in_addr *addr)
 	INIT_LIST_HEAD(&clp->cl_superblocks);
 	init_waitqueue_head(&clp->cl_waitq);
 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS4 client");
+	clp->cl_rpcclient = ERR_PTR(-EINVAL);
 	clp->cl_boot_time = CURRENT_TIME;
 	clp->cl_state = 1 << NFS4CLNT_OK;
 	return clp;
@@ -131,7 +132,7 @@ nfs4_free_client(struct nfs4_client *clp)
 	if (clp->cl_cred)
 		put_rpccred(clp->cl_cred);
 	nfs_idmap_delete(clp);
-	if (clp->cl_rpcclient)
+	if (!IS_ERR(clp->cl_rpcclient))
 		rpc_shutdown_client(clp->cl_rpcclient);
 	kfree(clp);
 	nfs_callback_down();

net/sunrpc/auth.c

@@ -66,10 +66,10 @@ rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
 	u32			flavor = pseudoflavor_to_flavor(pseudoflavor);
 
 	if (flavor >= RPC_AUTH_MAXFLAVOR || !(ops = auth_flavors[flavor]))
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	auth = ops->create(clnt, pseudoflavor);
-	if (!auth)
-		return NULL;
+	if (IS_ERR(auth))
+		return auth;
 	if (clnt->cl_auth)
 		rpcauth_destroy(clnt->cl_auth);
 	clnt->cl_auth = auth;

net/sunrpc/auth_gss/auth_gss.c

@@ -660,14 +660,16 @@ gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 {
 	struct gss_auth *gss_auth;
 	struct rpc_auth * auth;
+	int err = -ENOMEM; /* XXX? */
 
 	dprintk("RPC:      creating GSS authenticator for client %p\n",clnt);
 
 	if (!try_module_get(THIS_MODULE))
-		return NULL;
+		return ERR_PTR(err);
 	if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
 		goto out_dec;
 	gss_auth->client = clnt;
+	err = -EINVAL;
 	gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
 	if (!gss_auth->mech) {
 		printk(KERN_WARNING "%s: Pseudoflavor %d not found!",
@@ -686,15 +688,18 @@ gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 	auth->au_flavor = flavor;
 	atomic_set(&auth->au_count, 1);
 
-	if (rpcauth_init_credcache(auth, GSS_CRED_EXPIRE) < 0)
+	err = rpcauth_init_credcache(auth, GSS_CRED_EXPIRE);
+	if (err)
 		goto err_put_mech;
 
 	snprintf(gss_auth->path, sizeof(gss_auth->path), "%s/%s",
 			clnt->cl_pathname,
 			gss_auth->mech->gm_name);
 	gss_auth->dentry = rpc_mkpipe(gss_auth->path, clnt, &gss_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
-	if (IS_ERR(gss_auth->dentry))
+	if (IS_ERR(gss_auth->dentry)) {
+		err = PTR_ERR(gss_auth->dentry);
 		goto err_put_mech;
+	}
 
 	return auth;
 err_put_mech:
@@ -703,7 +708,7 @@ gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 	kfree(gss_auth);
 out_dec:
 	module_put(THIS_MODULE);
-	return NULL;
+	return ERR_PTR(err);
 }
 
 static void

net/sunrpc/clnt.c

@@ -103,6 +103,7 @@ rpc_new_client(struct rpc_xprt *xprt, char *servname,
 {
 	struct rpc_version	*version;
 	struct rpc_clnt		*clnt = NULL;
+	struct rpc_auth		*auth;
 	int err;
 	int len;
 
@@ -157,10 +158,11 @@ rpc_new_client(struct rpc_xprt *xprt, char *servname,
 	if (err < 0)
 		goto out_no_path;
 
-	err = -ENOMEM;
-	if (!rpcauth_create(flavor, clnt)) {
+	auth = rpcauth_create(flavor, clnt);
+	if (IS_ERR(auth)) {
 		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 				flavor);
+		err = PTR_ERR(auth);
 		goto out_no_auth;
 	}