net/sunrpc/clnt.c

   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/utsname.h>
  31 #include <linux/workqueue.h>
  32
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/rpc_pipe_fs.h>
  35 #include <linux/sunrpc/metrics.h>
  36
  37
  38 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  39
  40 #ifdef RPC_DEBUG
  41 # define RPCDBG_FACILITY        RPCDBG_CALL
  42 #endif
  43
  44 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  45
  46
  47 static void     call_start(struct rpc_task *task);
  48 static void     call_reserve(struct rpc_task *task);
  49 static void     call_reserveresult(struct rpc_task *task);
  50 static void     call_allocate(struct rpc_task *task);
  51 static void     call_encode(struct rpc_task *task);
  52 static void     call_decode(struct rpc_task *task);
  53 static void     call_bind(struct rpc_task *task);
  54 static void     call_bind_status(struct rpc_task *task);
  55 static void     call_transmit(struct rpc_task *task);
  56 static void     call_status(struct rpc_task *task);
  57 static void     call_transmit_status(struct rpc_task *task);
  58 static void     call_refresh(struct rpc_task *task);
  59 static void     call_refreshresult(struct rpc_task *task);
  60 static void     call_timeout(struct rpc_task *task);
  61 static void     call_connect(struct rpc_task *task);
  62 static void     call_connect_status(struct rpc_task *task);
  63 static u32 *    call_header(struct rpc_task *task);
  64 static u32 *    call_verify(struct rpc_task *task);
  65
  66
  67 static int
  68 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  69 {
  70         static uint32_t clntid;
  71         int error;
  72
  73         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  74         clnt->cl_dentry = ERR_PTR(-ENOENT);
  75         if (dir_name == NULL)
  76                 return 0;
  77
  78         clnt->cl_vfsmnt = rpc_get_mount();
  79         if (IS_ERR(clnt->cl_vfsmnt))
  80                 return PTR_ERR(clnt->cl_vfsmnt);
  81
  82         for (;;) {
  83                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  84                                 "%s/clnt%x", dir_name,
  85                                 (unsigned int)clntid++);
  86                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  87                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  88                 if (!IS_ERR(clnt->cl_dentry))
  89                         return 0;
  90                 error = PTR_ERR(clnt->cl_dentry);
  91                 if (error != -EEXIST) {
  92                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  93                                         clnt->cl_pathname, error);
  94                         rpc_put_mount();
  95                         return error;
  96                 }
  97         }
  98 }
  99
 100 /*
 101  * Create an RPC client
 102  * FIXME: This should also take a flags argument (as in task->tk_flags).
 103  * It's called (among others) from pmap_create_client, which may in
 104  * turn be called by an async task. In this case, rpciod should not be
 105  * made to sleep too long.
 106  */
 107 struct rpc_clnt *
 108 rpc_new_client(struct rpc_xprt *xprt, char *servname,
 109                   struct rpc_program *program, u32 vers,
 110                   rpc_authflavor_t flavor)
 111 {
 112         struct rpc_version      *version;
 113         struct rpc_clnt         *clnt = NULL;
 114         struct rpc_auth         *auth;
 115         int err;
 116         int len;
 117
 118         dprintk("RPC: creating %s client for %s (xprt %p)\n",
 119                 program->name, servname, xprt);
 120
 121         err = -EINVAL;
 122         if (!xprt)
 123                 goto out_no_xprt;
 124         if (vers >= program->nrvers || !(version = program->version[vers]))
 125                 goto out_err;
 126
 127         err = -ENOMEM;
 128         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 129         if (!clnt)
 130                 goto out_err;
 131         atomic_set(&clnt->cl_users, 0);
 132         atomic_set(&clnt->cl_count, 1);
 133         clnt->cl_parent = clnt;
 134
 135         clnt->cl_server = clnt->cl_inline_name;
 136         len = strlen(servname) + 1;
 137         if (len > sizeof(clnt->cl_inline_name)) {
 138                 char *buf = kmalloc(len, GFP_KERNEL);
 139                 if (buf != 0)
 140                         clnt->cl_server = buf;
 141                 else
 142                         len = sizeof(clnt->cl_inline_name);
 143         }
 144         strlcpy(clnt->cl_server, servname, len);
 145
 146         clnt->cl_xprt     = xprt;
 147         clnt->cl_procinfo = version->procs;
 148         clnt->cl_maxproc  = version->nrprocs;
 149         clnt->cl_protname = program->name;
 150         clnt->cl_pmap     = &clnt->cl_pmap_default;
 151         clnt->cl_port     = xprt->addr.sin_port;
 152         clnt->cl_prog     = program->number;
 153         clnt->cl_vers     = version->number;
 154         clnt->cl_prot     = xprt->prot;
 155         clnt->cl_stats    = program->stats;
 156         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 157         rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
 158
 159         if (!clnt->cl_port)
 160                 clnt->cl_autobind = 1;
 161
 162         clnt->cl_rtt = &clnt->cl_rtt_default;
 163         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 164
 165         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 166         if (err < 0)
 167                 goto out_no_path;
 168
 169         auth = rpcauth_create(flavor, clnt);
 170         if (IS_ERR(auth)) {
 171                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 172                                 flavor);
 173                 err = PTR_ERR(auth);
 174                 goto out_no_auth;
 175         }
 176
 177         /* save the nodename */
 178         clnt->cl_nodelen = strlen(system_utsname.nodename);
 179         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 180                 clnt->cl_nodelen = UNX_MAXNODENAME;
 181         memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
 182         return clnt;
 183
 184 out_no_auth:
 185         if (!IS_ERR(clnt->cl_dentry)) {
 186                 rpc_rmdir(clnt->cl_dentry);
 187                 dput(clnt->cl_dentry);
 188                 rpc_put_mount();
 189         }
 190 out_no_path:
 191         if (clnt->cl_server != clnt->cl_inline_name)
 192                 kfree(clnt->cl_server);
 193         kfree(clnt);
 194 out_err:
 195         xprt_destroy(xprt);
 196 out_no_xprt:
 197         return ERR_PTR(err);
 198 }
 199
 200 /**
 201  * Create an RPC client
 202  * @xprt - pointer to xprt struct
 203  * @servname - name of server
 204  * @info - rpc_program
 205  * @version - rpc_program version
 206  * @authflavor - rpc_auth flavour to use
 207  *
 208  * Creates an RPC client structure, then pings the server in order to
 209  * determine if it is up, and if it supports this program and version.
 210  *
 211  * This function should never be called by asynchronous tasks such as
 212  * the portmapper.
 213  */
 214 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
 215                 struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
 216 {
 217         struct rpc_clnt *clnt;
 218         int err;
 219
 220         clnt = rpc_new_client(xprt, servname, info, version, authflavor);
 221         if (IS_ERR(clnt))
 222                 return clnt;
 223         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 224         if (err == 0)
 225                 return clnt;
 226         rpc_shutdown_client(clnt);
 227         return ERR_PTR(err);
 228 }
 229
 230 /*
 231  * This function clones the RPC client structure. It allows us to share the
 232  * same transport while varying parameters such as the authentication
 233  * flavour.
 234  */
 235 struct rpc_clnt *
 236 rpc_clone_client(struct rpc_clnt *clnt)
 237 {
 238         struct rpc_clnt *new;
 239
 240         new = kmalloc(sizeof(*new), GFP_KERNEL);
 241         if (!new)
 242                 goto out_no_clnt;
 243         memcpy(new, clnt, sizeof(*new));
 244         atomic_set(&new->cl_count, 1);
 245         atomic_set(&new->cl_users, 0);
 246         new->cl_parent = clnt;
 247         atomic_inc(&clnt->cl_count);
 248         /* Duplicate portmapper */
 249         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
 250         /* Turn off autobind on clones */
 251         new->cl_autobind = 0;
 252         new->cl_oneshot = 0;
 253         new->cl_dead = 0;
 254         if (!IS_ERR(new->cl_dentry)) {
 255                 dget(new->cl_dentry);
 256                 rpc_get_mount();
 257         }
 258         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 259         if (new->cl_auth)
 260                 atomic_inc(&new->cl_auth->au_count);
 261         new->cl_pmap            = &new->cl_pmap_default;
 262         new->cl_metrics         = rpc_alloc_iostats(clnt);
 263         return new;
 264 out_no_clnt:
 265         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 266         return ERR_PTR(-ENOMEM);
 267 }
 268
 269 /*
 270  * Properly shut down an RPC client, terminating all outstanding
 271  * requests. Note that we must be certain that cl_oneshot and
 272  * cl_dead are cleared, or else the client would be destroyed
 273  * when the last task releases it.
 274  */
 275 int
 276 rpc_shutdown_client(struct rpc_clnt *clnt)
 277 {
 278         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 279                         clnt->cl_protname, clnt->cl_server,
 280                         atomic_read(&clnt->cl_users));
 281
 282         while (atomic_read(&clnt->cl_users) > 0) {
 283                 /* Don't let rpc_release_client destroy us */
 284                 clnt->cl_oneshot = 0;
 285                 clnt->cl_dead = 0;
 286                 rpc_killall_tasks(clnt);
 287                 wait_event_timeout(destroy_wait,
 288                         !atomic_read(&clnt->cl_users), 1*HZ);
 289         }
 290
 291         if (atomic_read(&clnt->cl_users) < 0) {
 292                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 293                                 clnt, atomic_read(&clnt->cl_users));
 294 #ifdef RPC_DEBUG
 295                 rpc_show_tasks();
 296 #endif
 297                 BUG();
 298         }
 299
 300         return rpc_destroy_client(clnt);
 301 }
 302
 303 /*
 304  * Delete an RPC client
 305  */
 306 int
 307 rpc_destroy_client(struct rpc_clnt *clnt)
 308 {
 309         if (!atomic_dec_and_test(&clnt->cl_count))
 310                 return 1;
 311         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 312
 313         dprintk("RPC: destroying %s client for %s\n",
 314                         clnt->cl_protname, clnt->cl_server);
 315         if (clnt->cl_auth) {
 316                 rpcauth_destroy(clnt->cl_auth);
 317                 clnt->cl_auth = NULL;
 318         }
 319         if (clnt->cl_parent != clnt) {
 320                 rpc_destroy_client(clnt->cl_parent);
 321                 goto out_free;
 322         }
 323         if (!IS_ERR(clnt->cl_dentry))
 324                 rpc_rmdir(clnt->cl_dentry);
 325         if (clnt->cl_xprt) {
 326                 xprt_destroy(clnt->cl_xprt);
 327                 clnt->cl_xprt = NULL;
 328         }
 329         if (clnt->cl_server != clnt->cl_inline_name)
 330                 kfree(clnt->cl_server);
 331 out_free:
 332         rpc_free_iostats(clnt->cl_metrics);
 333         clnt->cl_metrics = NULL;
 334         if (!IS_ERR(clnt->cl_dentry)) {
 335                 dput(clnt->cl_dentry);
 336                 rpc_put_mount();
 337         }
 338         kfree(clnt);
 339         return 0;
 340 }
 341
 342 /*
 343  * Release an RPC client
 344  */
 345 void
 346 rpc_release_client(struct rpc_clnt *clnt)
 347 {
 348         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 349                                 clnt, atomic_read(&clnt->cl_users));
 350
 351         if (!atomic_dec_and_test(&clnt->cl_users))
 352                 return;
 353         wake_up(&destroy_wait);
 354         if (clnt->cl_oneshot || clnt->cl_dead)
 355                 rpc_destroy_client(clnt);
 356 }
 357
 358 /**
 359  * rpc_bind_new_program - bind a new RPC program to an existing client
 360  * @old - old rpc_client
 361  * @program - rpc program to set
 362  * @vers - rpc program version
 363  *
 364  * Clones the rpc client and sets up a new RPC program. This is mainly
 365  * of use for enabling different RPC programs to share the same transport.
 366  * The Sun NFSv2/v3 ACL protocol can do this.
 367  */
 368 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 369                                       struct rpc_program *program,
 370                                       int vers)
 371 {
 372         struct rpc_clnt *clnt;
 373         struct rpc_version *version;
 374         int err;
 375
 376         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 377         version = program->version[vers];
 378         clnt = rpc_clone_client(old);
 379         if (IS_ERR(clnt))
 380                 goto out;
 381         clnt->cl_procinfo = version->procs;
 382         clnt->cl_maxproc  = version->nrprocs;
 383         clnt->cl_protname = program->name;
 384         clnt->cl_prog     = program->number;
 385         clnt->cl_vers     = version->number;
 386         clnt->cl_stats    = program->stats;
 387         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 388         if (err != 0) {
 389                 rpc_shutdown_client(clnt);
 390                 clnt = ERR_PTR(err);
 391         }
 392 out:
 393         return clnt;
 394 }
 395
 396 /*
 397  * Default callback for async RPC calls
 398  */
 399 static void
 400 rpc_default_callback(struct rpc_task *task, void *data)
 401 {
 402 }
 403
 404 static const struct rpc_call_ops rpc_default_ops = {
 405         .rpc_call_done = rpc_default_callback,
 406 };
 407
 408 /*
 409  *      Export the signal mask handling for synchronous code that
 410  *      sleeps on RPC calls
 411  */
 412 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 413
 414 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 415 {
 416         unsigned long   sigallow = sigmask(SIGKILL);
 417         sigset_t sigmask;
 418
 419         /* Block all signals except those listed in sigallow */
 420         if (intr)
 421                 sigallow |= RPC_INTR_SIGNALS;
 422         siginitsetinv(&sigmask, sigallow);
 423         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 424 }
 425
 426 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 427 {
 428         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 429 }
 430
 431 static inline void rpc_restore_sigmask(sigset_t *oldset)
 432 {
 433         sigprocmask(SIG_SETMASK, oldset, NULL);
 434 }
 435
 436 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 437 {
 438         rpc_save_sigmask(oldset, clnt->cl_intr);
 439 }
 440
 441 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 442 {
 443         rpc_restore_sigmask(oldset);
 444 }
 445
 446 /*
 447  * New rpc_call implementation
 448  */
 449 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 450 {
 451         struct rpc_task *task;
 452         sigset_t        oldset;
 453         int             status;
 454
 455         /* If this client is slain all further I/O fails */
 456         if (clnt->cl_dead)
 457                 return -EIO;
 458
 459         BUG_ON(flags & RPC_TASK_ASYNC);
 460
 461         status = -ENOMEM;
 462         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 463         if (task == NULL)
 464                 goto out;
 465
 466         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 467         rpc_task_sigmask(task, &oldset);
 468
 469         rpc_call_setup(task, msg, 0);
 470
 471         /* Set up the call info struct and execute the task */
 472         status = task->tk_status;
 473         if (status == 0) {
 474                 atomic_inc(&task->tk_count);
 475                 status = rpc_execute(task);
 476                 if (status == 0)
 477                         status = task->tk_status;
 478         }
 479         rpc_restore_sigmask(&oldset);
 480         rpc_release_task(task);
 481 out:
 482         return status;
 483 }
 484
 485 /*
 486  * New rpc_call implementation
 487  */
 488 int
 489 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 490                const struct rpc_call_ops *tk_ops, void *data)
 491 {
 492         struct rpc_task *task;
 493         sigset_t        oldset;
 494         int             status;
 495
 496         /* If this client is slain all further I/O fails */
 497         status = -EIO;
 498         if (clnt->cl_dead)
 499                 goto out_release;
 500
 501         flags |= RPC_TASK_ASYNC;
 502
 503         /* Create/initialize a new RPC task */
 504         status = -ENOMEM;
 505         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 506                 goto out_release;
 507
 508         /* Mask signals on GSS_AUTH upcalls */
 509         rpc_task_sigmask(task, &oldset);
 510
 511         rpc_call_setup(task, msg, 0);
 512
 513         /* Set up the call info struct and execute the task */
 514         status = task->tk_status;
 515         if (status == 0)
 516                 rpc_execute(task);
 517         else
 518                 rpc_release_task(task);
 519
 520         rpc_restore_sigmask(&oldset);
 521         return status;
 522 out_release:
 523         if (tk_ops->rpc_release != NULL)
 524                 tk_ops->rpc_release(data);
 525         return status;
 526 }
 527
 528
 529 void
 530 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 531 {
 532         task->tk_msg   = *msg;
 533         task->tk_flags |= flags;
 534         /* Bind the user cred */
 535         if (task->tk_msg.rpc_cred != NULL)
 536                 rpcauth_holdcred(task);
 537         else
 538                 rpcauth_bindcred(task);
 539
 540         if (task->tk_status == 0)
 541                 task->tk_action = call_start;
 542         else
 543                 task->tk_action = rpc_exit_task;
 544 }
 545
 546 void
 547 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 548 {
 549         struct rpc_xprt *xprt = clnt->cl_xprt;
 550         if (xprt->ops->set_buffer_size)
 551                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 552 }
 553
 554 /*
 555  * Return size of largest payload RPC client can support, in bytes
 556  *
 557  * For stream transports, this is one RPC record fragment (see RFC
 558  * 1831), as we don't support multi-record requests yet.  For datagram
 559  * transports, this is the size of an IP packet minus the IP, UDP, and
 560  * RPC header sizes.
 561  */
 562 size_t rpc_max_payload(struct rpc_clnt *clnt)
 563 {
 564         return clnt->cl_xprt->max_payload;
 565 }
 566 EXPORT_SYMBOL(rpc_max_payload);
 567
 568 /**
 569  * rpc_force_rebind - force transport to check that remote port is unchanged
 570  * @clnt: client to rebind
 571  *
 572  */
 573 void rpc_force_rebind(struct rpc_clnt *clnt)
 574 {
 575         if (clnt->cl_autobind)
 576                 clnt->cl_port = 0;
 577 }
 578 EXPORT_SYMBOL(rpc_force_rebind);
 579
 580 /*
 581  * Restart an (async) RPC call. Usually called from within the
 582  * exit handler.
 583  */
 584 void
 585 rpc_restart_call(struct rpc_task *task)
 586 {
 587         if (RPC_ASSASSINATED(task))
 588                 return;
 589
 590         task->tk_action = call_start;
 591 }
 592
 593 /*
 594  * 0.  Initial state
 595  *
 596  *     Other FSM states can be visited zero or more times, but
 597  *     this state is visited exactly once for each RPC.
 598  */
 599 static void
 600 call_start(struct rpc_task *task)
 601 {
 602         struct rpc_clnt *clnt = task->tk_client;
 603
 604         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 605                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 606                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 607
 608         /* Increment call count */
 609         task->tk_msg.rpc_proc->p_count++;
 610         clnt->cl_stats->rpccnt++;
 611         task->tk_action = call_reserve;
 612 }
 613
 614 /*
 615  * 1.   Reserve an RPC call slot
 616  */
 617 static void
 618 call_reserve(struct rpc_task *task)
 619 {
 620         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 621
 622         if (!rpcauth_uptodatecred(task)) {
 623                 task->tk_action = call_refresh;
 624                 return;
 625         }
 626
 627         task->tk_status  = 0;
 628         task->tk_action  = call_reserveresult;
 629         xprt_reserve(task);
 630 }
 631
 632 /*
 633  * 1b.  Grok the result of xprt_reserve()
 634  */
 635 static void
 636 call_reserveresult(struct rpc_task *task)
 637 {
 638         int status = task->tk_status;
 639
 640         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 641                                 task->tk_pid, task->tk_status);
 642
 643         /*
 644          * After a call to xprt_reserve(), we must have either
 645          * a request slot or else an error status.
 646          */
 647         task->tk_status = 0;
 648         if (status >= 0) {
 649                 if (task->tk_rqstp) {
 650                         task->tk_action = call_allocate;
 651                         return;
 652                 }
 653
 654                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 655                                 __FUNCTION__, status);
 656                 rpc_exit(task, -EIO);
 657                 return;
 658         }
 659
 660         /*
 661          * Even though there was an error, we may have acquired
 662          * a request slot somehow.  Make sure not to leak it.
 663          */
 664         if (task->tk_rqstp) {
 665                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 666                                 __FUNCTION__, status);
 667                 xprt_release(task);
 668         }
 669
 670         switch (status) {
 671         case -EAGAIN:   /* woken up; retry */
 672                 task->tk_action = call_reserve;
 673                 return;
 674         case -EIO:      /* probably a shutdown */
 675                 break;
 676         default:
 677                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 678                                 __FUNCTION__, status);
 679                 break;
 680         }
 681         rpc_exit(task, status);
 682 }
 683
 684 /*
 685  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 686  *      (Note: buffer memory is freed in xprt_release).
 687  */
 688 static void
 689 call_allocate(struct rpc_task *task)
 690 {
 691         struct rpc_rqst *req = task->tk_rqstp;
 692         struct rpc_xprt *xprt = task->tk_xprt;
 693         unsigned int    bufsiz;
 694
 695         dprintk("RPC: %4d call_allocate (status %d)\n",
 696                                 task->tk_pid, task->tk_status);
 697         task->tk_action = call_bind;
 698         if (req->rq_buffer)
 699                 return;
 700
 701         /* FIXME: compute buffer requirements more exactly using
 702          * auth->au_wslack */
 703         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 704
 705         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 706                 return;
 707         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 708
 709         if (RPC_IS_ASYNC(task) || !signalled()) {
 710                 xprt_release(task);
 711                 task->tk_action = call_reserve;
 712                 rpc_delay(task, HZ>>4);
 713                 return;
 714         }
 715
 716         rpc_exit(task, -ERESTARTSYS);
 717 }
 718
 719 static inline int
 720 rpc_task_need_encode(struct rpc_task *task)
 721 {
 722         return task->tk_rqstp->rq_snd_buf.len == 0;
 723 }
 724
 725 static inline void
 726 rpc_task_force_reencode(struct rpc_task *task)
 727 {
 728         task->tk_rqstp->rq_snd_buf.len = 0;
 729 }
 730
 731 /*
 732  * 3.   Encode arguments of an RPC call
 733  */
 734 static void
 735 call_encode(struct rpc_task *task)
 736 {
 737         struct rpc_rqst *req = task->tk_rqstp;
 738         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 739         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 740         unsigned int    bufsiz;
 741         kxdrproc_t      encode;
 742         u32             *p;
 743
 744         dprintk("RPC: %4d call_encode (status %d)\n",
 745                                 task->tk_pid, task->tk_status);
 746
 747         /* Default buffer setup */
 748         bufsiz = req->rq_bufsize >> 1;
 749         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 750         sndbuf->head[0].iov_len  = bufsiz;
 751         sndbuf->tail[0].iov_len  = 0;
 752         sndbuf->page_len         = 0;
 753         sndbuf->len              = 0;
 754         sndbuf->buflen           = bufsiz;
 755         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 756         rcvbuf->head[0].iov_len  = bufsiz;
 757         rcvbuf->tail[0].iov_len  = 0;
 758         rcvbuf->page_len         = 0;
 759         rcvbuf->len              = 0;
 760         rcvbuf->buflen           = bufsiz;
 761
 762         /* Encode header and provided arguments */
 763         encode = task->tk_msg.rpc_proc->p_encode;
 764         if (!(p = call_header(task))) {
 765                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 766                 rpc_exit(task, -EIO);
 767                 return;
 768         }
 769         if (encode == NULL)
 770                 return;
 771
 772         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 773                         task->tk_msg.rpc_argp);
 774         if (task->tk_status == -ENOMEM) {
 775                 /* XXX: Is this sane? */
 776                 rpc_delay(task, 3*HZ);
 777                 task->tk_status = -EAGAIN;
 778         }
 779 }
 780
 781 /*
 782  * 4.   Get the server port number if not yet set
 783  */
 784 static void
 785 call_bind(struct rpc_task *task)
 786 {
 787         struct rpc_clnt *clnt = task->tk_client;
 788
 789         dprintk("RPC: %4d call_bind (status %d)\n",
 790                                 task->tk_pid, task->tk_status);
 791
 792         task->tk_action = call_connect;
 793         if (!clnt->cl_port) {
 794                 task->tk_action = call_bind_status;
 795                 task->tk_timeout = task->tk_xprt->bind_timeout;
 796                 rpc_getport(task, clnt);
 797         }
 798 }
 799
 800 /*
 801  * 4a.  Sort out bind result
 802  */
 803 static void
 804 call_bind_status(struct rpc_task *task)
 805 {
 806         int status = -EACCES;
 807
 808         if (task->tk_status >= 0) {
 809                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 810                                         task->tk_pid, task->tk_status);
 811                 task->tk_status = 0;
 812                 task->tk_action = call_connect;
 813                 return;
 814         }
 815
 816         switch (task->tk_status) {
 817         case -EACCES:
 818                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 819                                 task->tk_pid);
 820                 rpc_delay(task, 3*HZ);
 821                 goto retry_bind;
 822         case -ETIMEDOUT:
 823                 dprintk("RPC: %4d rpcbind request timed out\n",
 824                                 task->tk_pid);
 825                 if (RPC_IS_SOFT(task)) {
 826                         status = -EIO;
 827                         break;
 828                 }
 829                 goto retry_bind;
 830         case -EPFNOSUPPORT:
 831                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 832                                 task->tk_pid);
 833                 break;
 834         case -EPROTONOSUPPORT:
 835                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 836                                 task->tk_pid);
 837                 break;
 838         default:
 839                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 840                                 task->tk_pid, -task->tk_status);
 841                 status = -EIO;
 842                 break;
 843         }
 844
 845         rpc_exit(task, status);
 846         return;
 847
 848 retry_bind:
 849         task->tk_status = 0;
 850         task->tk_action = call_bind;
 851         return;
 852 }
 853
 854 /*
 855  * 4b.  Connect to the RPC server
 856  */
 857 static void
 858 call_connect(struct rpc_task *task)
 859 {
 860         struct rpc_xprt *xprt = task->tk_xprt;
 861
 862         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 863                         task->tk_pid, xprt,
 864                         (xprt_connected(xprt) ? "is" : "is not"));
 865
 866         task->tk_action = call_transmit;
 867         if (!xprt_connected(xprt)) {
 868                 task->tk_action = call_connect_status;
 869                 if (task->tk_status < 0)
 870                         return;
 871                 xprt_connect(task);
 872         }
 873 }
 874
 875 /*
 876  * 4c.  Sort out connect result
 877  */
 878 static void
 879 call_connect_status(struct rpc_task *task)
 880 {
 881         struct rpc_clnt *clnt = task->tk_client;
 882         int status = task->tk_status;
 883
 884         dprintk("RPC: %5u call_connect_status (status %d)\n",
 885                                 task->tk_pid, task->tk_status);
 886
 887         task->tk_status = 0;
 888         if (status >= 0) {
 889                 clnt->cl_stats->netreconn++;
 890                 task->tk_action = call_transmit;
 891                 return;
 892         }
 893
 894         /* Something failed: remote service port may have changed */
 895         rpc_force_rebind(clnt);
 896
 897         switch (status) {
 898         case -ENOTCONN:
 899         case -ETIMEDOUT:
 900         case -EAGAIN:
 901                 task->tk_action = call_bind;
 902                 break;
 903         default:
 904                 rpc_exit(task, -EIO);
 905                 break;
 906         }
 907 }
 908
 909 /*
 910  * 5.   Transmit the RPC request, and wait for reply
 911  */
 912 static void
 913 call_transmit(struct rpc_task *task)
 914 {
 915         dprintk("RPC: %4d call_transmit (status %d)\n",
 916                                 task->tk_pid, task->tk_status);
 917
 918         task->tk_action = call_status;
 919         if (task->tk_status < 0)
 920                 return;
 921         task->tk_status = xprt_prepare_transmit(task);
 922         if (task->tk_status != 0)
 923                 return;
 924         task->tk_action = call_transmit_status;
 925         /* Encode here so that rpcsec_gss can use correct sequence number. */
 926         if (rpc_task_need_encode(task)) {
 927                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 928                 call_encode(task);
 929                 /* Did the encode result in an error condition? */
 930                 if (task->tk_status != 0)
 931                         return;
 932         }
 933         xprt_transmit(task);
 934         if (task->tk_status < 0)
 935                 return;
 936         /*
 937          * On success, ensure that we call xprt_end_transmit() before sleeping
 938          * in order to allow access to the socket to other RPC requests.
 939          */
 940         call_transmit_status(task);
 941         if (task->tk_msg.rpc_proc->p_decode != NULL)
 942                 return;
 943         task->tk_action = rpc_exit_task;
 944         rpc_wake_up_task(task);
 945 }
 946
 947 /*
 948  * 5a.  Handle cleanup after a transmission
 949  */
 950 static void
 951 call_transmit_status(struct rpc_task *task)
 952 {
 953         task->tk_action = call_status;
 954         /*
 955          * Special case: if we've been waiting on the socket's write_space()
 956          * callback, then don't call xprt_end_transmit().
 957          */
 958         if (task->tk_status == -EAGAIN)
 959                 return;
 960         xprt_end_transmit(task);
 961         rpc_task_force_reencode(task);
 962 }
 963
 964 /*
 965  * 6.   Sort out the RPC call status
 966  */
 967 static void
 968 call_status(struct rpc_task *task)
 969 {
 970         struct rpc_clnt *clnt = task->tk_client;
 971         struct rpc_rqst *req = task->tk_rqstp;
 972         int             status;
 973
 974         if (req->rq_received > 0 && !req->rq_bytes_sent)
 975                 task->tk_status = req->rq_received;
 976
 977         dprintk("RPC: %4d call_status (status %d)\n",
 978                                 task->tk_pid, task->tk_status);
 979
 980         status = task->tk_status;
 981         if (status >= 0) {
 982                 task->tk_action = call_decode;
 983                 return;
 984         }
 985
 986         task->tk_status = 0;
 987         switch(status) {
 988         case -ETIMEDOUT:
 989                 task->tk_action = call_timeout;
 990                 break;
 991         case -ECONNREFUSED:
 992         case -ENOTCONN:
 993                 rpc_force_rebind(clnt);
 994                 task->tk_action = call_bind;
 995                 break;
 996         case -EAGAIN:
 997                 task->tk_action = call_transmit;
 998                 break;
 999         case -EIO:
1000                 /* shutdown or soft timeout */
1001                 rpc_exit(task, status);
1002                 break;
1003         default:
1004                 printk("%s: RPC call returned error %d\n",
1005                                clnt->cl_protname, -status);
1006                 rpc_exit(task, status);
1007                 break;
1008         }
1009 }
1010
1011 /*
1012  * 6a.  Handle RPC timeout
1013  *      We do not release the request slot, so we keep using the
1014  *      same XID for all retransmits.
1015  */
1016 static void
1017 call_timeout(struct rpc_task *task)
1018 {
1019         struct rpc_clnt *clnt = task->tk_client;
1020
1021         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1022                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1023                 goto retry;
1024         }
1025
1026         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1027         task->tk_timeouts++;
1028
1029         if (RPC_IS_SOFT(task)) {
1030                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1031                                 clnt->cl_protname, clnt->cl_server);
1032                 rpc_exit(task, -EIO);
1033                 return;
1034         }
1035
1036         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1037                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1038                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1039                         clnt->cl_protname, clnt->cl_server);
1040         }
1041         rpc_force_rebind(clnt);
1042
1043 retry:
1044         clnt->cl_stats->rpcretrans++;
1045         task->tk_action = call_bind;
1046         task->tk_status = 0;
1047 }
1048
1049 /*
1050  * 7.   Decode the RPC reply
1051  */
1052 static void
1053 call_decode(struct rpc_task *task)
1054 {
1055         struct rpc_clnt *clnt = task->tk_client;
1056         struct rpc_rqst *req = task->tk_rqstp;
1057         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1058         u32             *p;
1059
1060         dprintk("RPC: %4d call_decode (status %d)\n",
1061                                 task->tk_pid, task->tk_status);
1062
1063         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1064                 printk(KERN_NOTICE "%s: server %s OK\n",
1065                         clnt->cl_protname, clnt->cl_server);
1066                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1067         }
1068
1069         if (task->tk_status < 12) {
1070                 if (!RPC_IS_SOFT(task)) {
1071                         task->tk_action = call_bind;
1072                         clnt->cl_stats->rpcretrans++;
1073                         goto out_retry;
1074                 }
1075                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1076                         clnt->cl_protname, task->tk_status);
1077                 rpc_exit(task, -EIO);
1078                 return;
1079         }
1080
1081         /*
1082          * Ensure that we see all writes made by xprt_complete_rqst()
1083          * before it changed req->rq_received.
1084          */
1085         smp_rmb();
1086         req->rq_rcv_buf.len = req->rq_private_buf.len;
1087
1088         /* Check that the softirq receive buffer is valid */
1089         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1090                                 sizeof(req->rq_rcv_buf)) != 0);
1091
1092         /* Verify the RPC header */
1093         p = call_verify(task);
1094         if (IS_ERR(p)) {
1095                 if (p == ERR_PTR(-EAGAIN))
1096                         goto out_retry;
1097                 return;
1098         }
1099
1100         task->tk_action = rpc_exit_task;
1101
1102         if (decode)
1103                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1104                                                       task->tk_msg.rpc_resp);
1105         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1106                                         task->tk_status);
1107         return;
1108 out_retry:
1109         req->rq_received = req->rq_private_buf.len = 0;
1110         task->tk_status = 0;
1111 }
1112
1113 /*
1114  * 8.   Refresh the credentials if rejected by the server
1115  */
1116 static void
1117 call_refresh(struct rpc_task *task)
1118 {
1119         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1120
1121         xprt_release(task);     /* Must do to obtain new XID */
1122         task->tk_action = call_refreshresult;
1123         task->tk_status = 0;
1124         task->tk_client->cl_stats->rpcauthrefresh++;
1125         rpcauth_refreshcred(task);
1126 }
1127
1128 /*
1129  * 8a.  Process the results of a credential refresh
1130  */
1131 static void
1132 call_refreshresult(struct rpc_task *task)
1133 {
1134         int status = task->tk_status;
1135         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1136                                 task->tk_pid, task->tk_status);
1137
1138         task->tk_status = 0;
1139         task->tk_action = call_reserve;
1140         if (status >= 0 && rpcauth_uptodatecred(task))
1141                 return;
1142         if (status == -EACCES) {
1143                 rpc_exit(task, -EACCES);
1144                 return;
1145         }
1146         task->tk_action = call_refresh;
1147         if (status != -ETIMEDOUT)
1148                 rpc_delay(task, 3*HZ);
1149         return;
1150 }
1151
1152 /*
1153  * Call header serialization
1154  */
1155 static u32 *
1156 call_header(struct rpc_task *task)
1157 {
1158         struct rpc_clnt *clnt = task->tk_client;
1159         struct rpc_rqst *req = task->tk_rqstp;
1160         u32             *p = req->rq_svec[0].iov_base;
1161
1162         /* FIXME: check buffer size? */
1163
1164         p = xprt_skip_transport_header(task->tk_xprt, p);
1165         *p++ = req->rq_xid;             /* XID */
1166         *p++ = htonl(RPC_CALL);         /* CALL */
1167         *p++ = htonl(RPC_VERSION);      /* RPC version */
1168         *p++ = htonl(clnt->cl_prog);    /* program number */
1169         *p++ = htonl(clnt->cl_vers);    /* program version */
1170         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1171         p = rpcauth_marshcred(task, p);
1172         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1173         return p;
1174 }
1175
1176 /*
1177  * Reply header verification
1178  */
1179 static u32 *
1180 call_verify(struct rpc_task *task)
1181 {
1182         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1183         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1184         u32     *p = iov->iov_base, n;
1185         int error = -EACCES;
1186
1187         if ((len -= 3) < 0)
1188                 goto out_overflow;
1189         p += 1; /* skip XID */
1190
1191         if ((n = ntohl(*p++)) != RPC_REPLY) {
1192                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1193                 goto out_garbage;
1194         }
1195         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1196                 if (--len < 0)
1197                         goto out_overflow;
1198                 switch ((n = ntohl(*p++))) {
1199                         case RPC_AUTH_ERROR:
1200                                 break;
1201                         case RPC_MISMATCH:
1202                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1203                                 error = -EPROTONOSUPPORT;
1204                                 goto out_err;
1205                         default:
1206                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1207                                 goto out_eio;
1208                 }
1209                 if (--len < 0)
1210                         goto out_overflow;
1211                 switch ((n = ntohl(*p++))) {
1212                 case RPC_AUTH_REJECTEDCRED:
1213                 case RPC_AUTH_REJECTEDVERF:
1214                 case RPCSEC_GSS_CREDPROBLEM:
1215                 case RPCSEC_GSS_CTXPROBLEM:
1216                         if (!task->tk_cred_retry)
1217                                 break;
1218                         task->tk_cred_retry--;
1219                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1220                                                         task->tk_pid);
1221                         rpcauth_invalcred(task);
1222                         task->tk_action = call_refresh;
1223                         goto out_retry;
1224                 case RPC_AUTH_BADCRED:
1225                 case RPC_AUTH_BADVERF:
1226                         /* possibly garbled cred/verf? */
1227                         if (!task->tk_garb_retry)
1228                                 break;
1229                         task->tk_garb_retry--;
1230                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1231                                                         task->tk_pid);
1232                         task->tk_action = call_bind;
1233                         goto out_retry;
1234                 case RPC_AUTH_TOOWEAK:
1235                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1236                                "authentication.\n", task->tk_client->cl_server);
1237                         break;
1238                 default:
1239                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1240                         error = -EIO;
1241                 }
1242                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1243                                                 task->tk_pid, n);
1244                 goto out_err;
1245         }
1246         if (!(p = rpcauth_checkverf(task, p))) {
1247                 printk(KERN_WARNING "call_verify: auth check failed\n");
1248                 goto out_garbage;               /* bad verifier, retry */
1249         }
1250         len = p - (u32 *)iov->iov_base - 1;
1251         if (len < 0)
1252                 goto out_overflow;
1253         switch ((n = ntohl(*p++))) {
1254         case RPC_SUCCESS:
1255                 return p;
1256         case RPC_PROG_UNAVAIL:
1257                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1258                                 (unsigned int)task->tk_client->cl_prog,
1259                                 task->tk_client->cl_server);
1260                 error = -EPFNOSUPPORT;
1261                 goto out_err;
1262         case RPC_PROG_MISMATCH:
1263                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1264                                 (unsigned int)task->tk_client->cl_prog,
1265                                 (unsigned int)task->tk_client->cl_vers,
1266                                 task->tk_client->cl_server);
1267                 error = -EPROTONOSUPPORT;
1268                 goto out_err;
1269         case RPC_PROC_UNAVAIL:
1270                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1271                                 task->tk_msg.rpc_proc,
1272                                 task->tk_client->cl_prog,
1273                                 task->tk_client->cl_vers,
1274                                 task->tk_client->cl_server);
1275                 error = -EOPNOTSUPP;
1276                 goto out_err;
1277         case RPC_GARBAGE_ARGS:
1278                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1279                 break;                  /* retry */
1280         default:
1281                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1282                 /* Also retry */
1283         }
1284
1285 out_garbage:
1286         task->tk_client->cl_stats->rpcgarbage++;
1287         if (task->tk_garb_retry) {
1288                 task->tk_garb_retry--;
1289                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1290                 task->tk_action = call_bind;
1291 out_retry:
1292                 return ERR_PTR(-EAGAIN);
1293         }
1294         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1295 out_eio:
1296         error = -EIO;
1297 out_err:
1298         rpc_exit(task, error);
1299         return ERR_PTR(error);
1300 out_overflow:
1301         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1302         goto out_garbage;
1303 }
1304
1305 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1306 {
1307         return 0;
1308 }
1309
1310 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1311 {
1312         return 0;
1313 }
1314
1315 static struct rpc_procinfo rpcproc_null = {
1316         .p_encode = rpcproc_encode_null,
1317         .p_decode = rpcproc_decode_null,
1318 };
1319
1320 int rpc_ping(struct rpc_clnt *clnt, int flags)
1321 {
1322         struct rpc_message msg = {
1323                 .rpc_proc = &rpcproc_null,
1324         };
1325         int err;
1326         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1327         err = rpc_call_sync(clnt, &msg, flags);
1328         put_rpccred(msg.rpc_cred);
1329         return err;
1330 }