git.oblomov.eu Git - linux-2.6/blob - 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 = kmalloc(sizeof(*clnt), GFP_KERNEL);
 129         if (!clnt)
 130                 goto out_err;
 131         memset(clnt, 0, sizeof(*clnt));
 132         atomic_set(&clnt->cl_users, 0);
 133         atomic_set(&clnt->cl_count, 1);
 134         clnt->cl_parent = clnt;
 135
 136         clnt->cl_server = clnt->cl_inline_name;
 137         len = strlen(servname) + 1;
 138         if (len > sizeof(clnt->cl_inline_name)) {
 139                 char *buf = kmalloc(len, GFP_KERNEL);
 140                 if (buf != 0)
 141                         clnt->cl_server = buf;
 142                 else
 143                         len = sizeof(clnt->cl_inline_name);
 144         }
 145         strlcpy(clnt->cl_server, servname, len);
 146
 147         clnt->cl_xprt     = xprt;
 148         clnt->cl_procinfo = version->procs;
 149         clnt->cl_maxproc  = version->nrprocs;
 150         clnt->cl_protname = program->name;
 151         clnt->cl_pmap     = &clnt->cl_pmap_default;
 152         clnt->cl_port     = xprt->addr.sin_port;
 153         clnt->cl_prog     = program->number;
 154         clnt->cl_vers     = version->number;
 155         clnt->cl_prot     = xprt->prot;
 156         clnt->cl_stats    = program->stats;
 157         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 158         rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
 159
 160         if (!clnt->cl_port)
 161                 clnt->cl_autobind = 1;
 162
 163         clnt->cl_rtt = &clnt->cl_rtt_default;
 164         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 165
 166         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 167         if (err < 0)
 168                 goto out_no_path;
 169
 170         auth = rpcauth_create(flavor, clnt);
 171         if (IS_ERR(auth)) {
 172                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 173                                 flavor);
 174                 err = PTR_ERR(auth);
 175                 goto out_no_auth;
 176         }
 177
 178         /* save the nodename */
 179         clnt->cl_nodelen = strlen(system_utsname.nodename);
 180         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 181                 clnt->cl_nodelen = UNX_MAXNODENAME;
 182         memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
 183         return clnt;
 184
 185 out_no_auth:
 186         if (!IS_ERR(clnt->cl_dentry)) {
 187                 rpc_rmdir(clnt->cl_pathname);
 188                 dput(clnt->cl_dentry);
 189                 rpc_put_mount();
 190         }
 191 out_no_path:
 192         if (clnt->cl_server != clnt->cl_inline_name)
 193                 kfree(clnt->cl_server);
 194         kfree(clnt);
 195 out_err:
 196         xprt_destroy(xprt);
 197 out_no_xprt:
 198         return ERR_PTR(err);
 199 }
 200
 201 /**
 202  * Create an RPC client
 203  * @xprt - pointer to xprt struct
 204  * @servname - name of server
 205  * @info - rpc_program
 206  * @version - rpc_program version
 207  * @authflavor - rpc_auth flavour to use
 208  *
 209  * Creates an RPC client structure, then pings the server in order to
 210  * determine if it is up, and if it supports this program and version.
 211  *
 212  * This function should never be called by asynchronous tasks such as
 213  * the portmapper.
 214  */
 215 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
 216                 struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
 217 {
 218         struct rpc_clnt *clnt;
 219         int err;
 220
 221         clnt = rpc_new_client(xprt, servname, info, version, authflavor);
 222         if (IS_ERR(clnt))
 223                 return clnt;
 224         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 225         if (err == 0)
 226                 return clnt;
 227         rpc_shutdown_client(clnt);
 228         return ERR_PTR(err);
 229 }
 230
 231 /*
 232  * This function clones the RPC client structure. It allows us to share the
 233  * same transport while varying parameters such as the authentication
 234  * flavour.
 235  */
 236 struct rpc_clnt *
 237 rpc_clone_client(struct rpc_clnt *clnt)
 238 {
 239         struct rpc_clnt *new;
 240
 241         new = kmalloc(sizeof(*new), GFP_KERNEL);
 242         if (!new)
 243                 goto out_no_clnt;
 244         memcpy(new, clnt, sizeof(*new));
 245         atomic_set(&new->cl_count, 1);
 246         atomic_set(&new->cl_users, 0);
 247         new->cl_parent = clnt;
 248         atomic_inc(&clnt->cl_count);
 249         /* Duplicate portmapper */
 250         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
 251         /* Turn off autobind on clones */
 252         new->cl_autobind = 0;
 253         new->cl_oneshot = 0;
 254         new->cl_dead = 0;
 255         if (!IS_ERR(new->cl_dentry)) {
 256                 dget(new->cl_dentry);
 257                 rpc_get_mount();
 258         }
 259         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 260         if (new->cl_auth)
 261                 atomic_inc(&new->cl_auth->au_count);
 262         new->cl_pmap            = &new->cl_pmap_default;
 263         new->cl_metrics         = rpc_alloc_iostats(clnt);
 264         return new;
 265 out_no_clnt:
 266         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 267         return ERR_PTR(-ENOMEM);
 268 }
 269
 270 /*
 271  * Properly shut down an RPC client, terminating all outstanding
 272  * requests. Note that we must be certain that cl_oneshot and
 273  * cl_dead are cleared, or else the client would be destroyed
 274  * when the last task releases it.
 275  */
 276 int
 277 rpc_shutdown_client(struct rpc_clnt *clnt)
 278 {
 279         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 280                         clnt->cl_protname, clnt->cl_server,
 281                         atomic_read(&clnt->cl_users));
 282
 283         while (atomic_read(&clnt->cl_users) > 0) {
 284                 /* Don't let rpc_release_client destroy us */
 285                 clnt->cl_oneshot = 0;
 286                 clnt->cl_dead = 0;
 287                 rpc_killall_tasks(clnt);
 288                 wait_event_timeout(destroy_wait,
 289                         !atomic_read(&clnt->cl_users), 1*HZ);
 290         }
 291
 292         if (atomic_read(&clnt->cl_users) < 0) {
 293                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 294                                 clnt, atomic_read(&clnt->cl_users));
 295 #ifdef RPC_DEBUG
 296                 rpc_show_tasks();
 297 #endif
 298                 BUG();
 299         }
 300
 301         return rpc_destroy_client(clnt);
 302 }
 303
 304 /*
 305  * Delete an RPC client
 306  */
 307 int
 308 rpc_destroy_client(struct rpc_clnt *clnt)
 309 {
 310         if (!atomic_dec_and_test(&clnt->cl_count))
 311                 return 1;
 312         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 313
 314         dprintk("RPC: destroying %s client for %s\n",
 315                         clnt->cl_protname, clnt->cl_server);
 316         if (clnt->cl_auth) {
 317                 rpcauth_destroy(clnt->cl_auth);
 318                 clnt->cl_auth = NULL;
 319         }
 320         if (clnt->cl_parent != clnt) {
 321                 rpc_destroy_client(clnt->cl_parent);
 322                 goto out_free;
 323         }
 324         if (clnt->cl_pathname[0])
 325                 rpc_rmdir(clnt->cl_pathname);
 326         if (clnt->cl_xprt) {
 327                 xprt_destroy(clnt->cl_xprt);
 328                 clnt->cl_xprt = NULL;
 329         }
 330         if (clnt->cl_server != clnt->cl_inline_name)
 331                 kfree(clnt->cl_server);
 332 out_free:
 333         rpc_free_iostats(clnt->cl_metrics);
 334         clnt->cl_metrics = NULL;
 335         if (!IS_ERR(clnt->cl_dentry)) {
 336                 dput(clnt->cl_dentry);
 337                 rpc_put_mount();
 338         }
 339         kfree(clnt);
 340         return 0;
 341 }
 342
 343 /*
 344  * Release an RPC client
 345  */
 346 void
 347 rpc_release_client(struct rpc_clnt *clnt)
 348 {
 349         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 350                                 clnt, atomic_read(&clnt->cl_users));
 351
 352         if (!atomic_dec_and_test(&clnt->cl_users))
 353                 return;
 354         wake_up(&destroy_wait);
 355         if (clnt->cl_oneshot || clnt->cl_dead)
 356                 rpc_destroy_client(clnt);
 357 }
 358
 359 /**
 360  * rpc_bind_new_program - bind a new RPC program to an existing client
 361  * @old - old rpc_client
 362  * @program - rpc program to set
 363  * @vers - rpc program version
 364  *
 365  * Clones the rpc client and sets up a new RPC program. This is mainly
 366  * of use for enabling different RPC programs to share the same transport.
 367  * The Sun NFSv2/v3 ACL protocol can do this.
 368  */
 369 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 370                                       struct rpc_program *program,
 371                                       int vers)
 372 {
 373         struct rpc_clnt *clnt;
 374         struct rpc_version *version;
 375         int err;
 376
 377         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 378         version = program->version[vers];
 379         clnt = rpc_clone_client(old);
 380         if (IS_ERR(clnt))
 381                 goto out;
 382         clnt->cl_procinfo = version->procs;
 383         clnt->cl_maxproc  = version->nrprocs;
 384         clnt->cl_protname = program->name;
 385         clnt->cl_prog     = program->number;
 386         clnt->cl_vers     = version->number;
 387         clnt->cl_stats    = program->stats;
 388         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 389         if (err != 0) {
 390                 rpc_shutdown_client(clnt);
 391                 clnt = ERR_PTR(err);
 392         }
 393 out:
 394         return clnt;
 395 }
 396
 397 /*
 398  * Default callback for async RPC calls
 399  */
 400 static void
 401 rpc_default_callback(struct rpc_task *task, void *data)
 402 {
 403 }
 404
 405 static const struct rpc_call_ops rpc_default_ops = {
 406         .rpc_call_done = rpc_default_callback,
 407 };
 408
 409 /*
 410  *      Export the signal mask handling for synchronous code that
 411  *      sleeps on RPC calls
 412  */
 413 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 414
 415 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 416 {
 417         unsigned long   sigallow = sigmask(SIGKILL);
 418         sigset_t sigmask;
 419
 420         /* Block all signals except those listed in sigallow */
 421         if (intr)
 422                 sigallow |= RPC_INTR_SIGNALS;
 423         siginitsetinv(&sigmask, sigallow);
 424         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 425 }
 426
 427 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 428 {
 429         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 430 }
 431
 432 static inline void rpc_restore_sigmask(sigset_t *oldset)
 433 {
 434         sigprocmask(SIG_SETMASK, oldset, NULL);
 435 }
 436
 437 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 438 {
 439         rpc_save_sigmask(oldset, clnt->cl_intr);
 440 }
 441
 442 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 443 {
 444         rpc_restore_sigmask(oldset);
 445 }
 446
 447 /*
 448  * New rpc_call implementation
 449  */
 450 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 451 {
 452         struct rpc_task *task;
 453         sigset_t        oldset;
 454         int             status;
 455
 456         /* If this client is slain all further I/O fails */
 457         if (clnt->cl_dead)
 458                 return -EIO;
 459
 460         BUG_ON(flags & RPC_TASK_ASYNC);
 461
 462         status = -ENOMEM;
 463         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 464         if (task == NULL)
 465                 goto out;
 466
 467         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 468         rpc_task_sigmask(task, &oldset);
 469
 470         rpc_call_setup(task, msg, 0);
 471
 472         /* Set up the call info struct and execute the task */
 473         status = task->tk_status;
 474         if (status == 0) {
 475                 atomic_inc(&task->tk_count);
 476                 status = rpc_execute(task);
 477                 if (status == 0)
 478                         status = task->tk_status;
 479         }
 480         rpc_restore_sigmask(&oldset);
 481         rpc_release_task(task);
 482 out:
 483         return status;
 484 }
 485
 486 /*
 487  * New rpc_call implementation
 488  */
 489 int
 490 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 491                const struct rpc_call_ops *tk_ops, void *data)
 492 {
 493         struct rpc_task *task;
 494         sigset_t        oldset;
 495         int             status;
 496
 497         /* If this client is slain all further I/O fails */
 498         status = -EIO;
 499         if (clnt->cl_dead)
 500                 goto out_release;
 501
 502         flags |= RPC_TASK_ASYNC;
 503
 504         /* Create/initialize a new RPC task */
 505         status = -ENOMEM;
 506         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 507                 goto out_release;
 508
 509         /* Mask signals on GSS_AUTH upcalls */
 510         rpc_task_sigmask(task, &oldset);
 511
 512         rpc_call_setup(task, msg, 0);
 513
 514         /* Set up the call info struct and execute the task */
 515         status = task->tk_status;
 516         if (status == 0)
 517                 rpc_execute(task);
 518         else
 519                 rpc_release_task(task);
 520
 521         rpc_restore_sigmask(&oldset);
 522         return status;
 523 out_release:
 524         if (tk_ops->rpc_release != NULL)
 525                 tk_ops->rpc_release(data);
 526         return status;
 527 }
 528
 529
 530 void
 531 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 532 {
 533         task->tk_msg   = *msg;
 534         task->tk_flags |= flags;
 535         /* Bind the user cred */
 536         if (task->tk_msg.rpc_cred != NULL)
 537                 rpcauth_holdcred(task);
 538         else
 539                 rpcauth_bindcred(task);
 540
 541         if (task->tk_status == 0)
 542                 task->tk_action = call_start;
 543         else
 544                 task->tk_action = rpc_exit_task;
 545 }
 546
 547 void
 548 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 549 {
 550         struct rpc_xprt *xprt = clnt->cl_xprt;
 551         if (xprt->ops->set_buffer_size)
 552                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 553 }
 554
 555 /*
 556  * Return size of largest payload RPC client can support, in bytes
 557  *
 558  * For stream transports, this is one RPC record fragment (see RFC
 559  * 1831), as we don't support multi-record requests yet.  For datagram
 560  * transports, this is the size of an IP packet minus the IP, UDP, and
 561  * RPC header sizes.
 562  */
 563 size_t rpc_max_payload(struct rpc_clnt *clnt)
 564 {
 565         return clnt->cl_xprt->max_payload;
 566 }
 567 EXPORT_SYMBOL(rpc_max_payload);
 568
 569 /**
 570  * rpc_force_rebind - force transport to check that remote port is unchanged
 571  * @clnt: client to rebind
 572  *
 573  */
 574 void rpc_force_rebind(struct rpc_clnt *clnt)
 575 {
 576         if (clnt->cl_autobind)
 577                 clnt->cl_port = 0;
 578 }
 579 EXPORT_SYMBOL(rpc_force_rebind);
 580
 581 /*
 582  * Restart an (async) RPC call. Usually called from within the
 583  * exit handler.
 584  */
 585 void
 586 rpc_restart_call(struct rpc_task *task)
 587 {
 588         if (RPC_ASSASSINATED(task))
 589                 return;
 590
 591         task->tk_action = call_start;
 592 }
 593
 594 /*
 595  * 0.  Initial state
 596  *
 597  *     Other FSM states can be visited zero or more times, but
 598  *     this state is visited exactly once for each RPC.
 599  */
 600 static void
 601 call_start(struct rpc_task *task)
 602 {
 603         struct rpc_clnt *clnt = task->tk_client;
 604
 605         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 606                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 607                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 608
 609         /* Increment call count */
 610         task->tk_msg.rpc_proc->p_count++;
 611         clnt->cl_stats->rpccnt++;
 612         task->tk_action = call_reserve;
 613 }
 614
 615 /*
 616  * 1.   Reserve an RPC call slot
 617  */
 618 static void
 619 call_reserve(struct rpc_task *task)
 620 {
 621         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 622
 623         if (!rpcauth_uptodatecred(task)) {
 624                 task->tk_action = call_refresh;
 625                 return;
 626         }
 627
 628         task->tk_status  = 0;
 629         task->tk_action  = call_reserveresult;
 630         xprt_reserve(task);
 631 }
 632
 633 /*
 634  * 1b.  Grok the result of xprt_reserve()
 635  */
 636 static void
 637 call_reserveresult(struct rpc_task *task)
 638 {
 639         int status = task->tk_status;
 640
 641         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 642                                 task->tk_pid, task->tk_status);
 643
 644         /*
 645          * After a call to xprt_reserve(), we must have either
 646          * a request slot or else an error status.
 647          */
 648         task->tk_status = 0;
 649         if (status >= 0) {
 650                 if (task->tk_rqstp) {
 651                         task->tk_action = call_allocate;
 652                         return;
 653                 }
 654
 655                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 656                                 __FUNCTION__, status);
 657                 rpc_exit(task, -EIO);
 658                 return;
 659         }
 660
 661         /*
 662          * Even though there was an error, we may have acquired
 663          * a request slot somehow.  Make sure not to leak it.
 664          */
 665         if (task->tk_rqstp) {
 666                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 667                                 __FUNCTION__, status);
 668                 xprt_release(task);
 669         }
 670
 671         switch (status) {
 672         case -EAGAIN:   /* woken up; retry */
 673                 task->tk_action = call_reserve;
 674                 return;
 675         case -EIO:      /* probably a shutdown */
 676                 break;
 677         default:
 678                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 679                                 __FUNCTION__, status);
 680                 break;
 681         }
 682         rpc_exit(task, status);
 683 }
 684
 685 /*
 686  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 687  *      (Note: buffer memory is freed in xprt_release).
 688  */
 689 static void
 690 call_allocate(struct rpc_task *task)
 691 {
 692         struct rpc_rqst *req = task->tk_rqstp;
 693         struct rpc_xprt *xprt = task->tk_xprt;
 694         unsigned int    bufsiz;
 695
 696         dprintk("RPC: %4d call_allocate (status %d)\n",
 697                                 task->tk_pid, task->tk_status);
 698         task->tk_action = call_bind;
 699         if (req->rq_buffer)
 700                 return;
 701
 702         /* FIXME: compute buffer requirements more exactly using
 703          * auth->au_wslack */
 704         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 705
 706         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 707                 return;
 708         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 709
 710         if (RPC_IS_ASYNC(task) || !signalled()) {
 711                 xprt_release(task);
 712                 task->tk_action = call_reserve;
 713                 rpc_delay(task, HZ>>4);
 714                 return;
 715         }
 716
 717         rpc_exit(task, -ERESTARTSYS);
 718 }
 719
 720 static inline int
 721 rpc_task_need_encode(struct rpc_task *task)
 722 {
 723         return task->tk_rqstp->rq_snd_buf.len == 0;
 724 }
 725
 726 static inline void
 727 rpc_task_force_reencode(struct rpc_task *task)
 728 {
 729         task->tk_rqstp->rq_snd_buf.len = 0;
 730 }
 731
 732 /*
 733  * 3.   Encode arguments of an RPC call
 734  */
 735 static void
 736 call_encode(struct rpc_task *task)
 737 {
 738         struct rpc_rqst *req = task->tk_rqstp;
 739         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 740         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 741         unsigned int    bufsiz;
 742         kxdrproc_t      encode;
 743         u32             *p;
 744
 745         dprintk("RPC: %4d call_encode (status %d)\n",
 746                                 task->tk_pid, task->tk_status);
 747
 748         /* Default buffer setup */
 749         bufsiz = req->rq_bufsize >> 1;
 750         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 751         sndbuf->head[0].iov_len  = bufsiz;
 752         sndbuf->tail[0].iov_len  = 0;
 753         sndbuf->page_len         = 0;
 754         sndbuf->len              = 0;
 755         sndbuf->buflen           = bufsiz;
 756         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 757         rcvbuf->head[0].iov_len  = bufsiz;
 758         rcvbuf->tail[0].iov_len  = 0;
 759         rcvbuf->page_len         = 0;
 760         rcvbuf->len              = 0;
 761         rcvbuf->buflen           = bufsiz;
 762
 763         /* Encode header and provided arguments */
 764         encode = task->tk_msg.rpc_proc->p_encode;
 765         if (!(p = call_header(task))) {
 766                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 767                 rpc_exit(task, -EIO);
 768                 return;
 769         }
 770         if (encode == NULL)
 771                 return;
 772
 773         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 774                         task->tk_msg.rpc_argp);
 775         if (task->tk_status == -ENOMEM) {
 776                 /* XXX: Is this sane? */
 777                 rpc_delay(task, 3*HZ);
 778                 task->tk_status = -EAGAIN;
 779         }
 780 }
 781
 782 /*
 783  * 4.   Get the server port number if not yet set
 784  */
 785 static void
 786 call_bind(struct rpc_task *task)
 787 {
 788         struct rpc_clnt *clnt = task->tk_client;
 789
 790         dprintk("RPC: %4d call_bind (status %d)\n",
 791                                 task->tk_pid, task->tk_status);
 792
 793         task->tk_action = call_connect;
 794         if (!clnt->cl_port) {
 795                 task->tk_action = call_bind_status;
 796                 task->tk_timeout = task->tk_xprt->bind_timeout;
 797                 rpc_getport(task, clnt);
 798         }
 799 }
 800
 801 /*
 802  * 4a.  Sort out bind result
 803  */
 804 static void
 805 call_bind_status(struct rpc_task *task)
 806 {
 807         int status = -EACCES;
 808
 809         if (task->tk_status >= 0) {
 810                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 811                                         task->tk_pid, task->tk_status);
 812                 task->tk_status = 0;
 813                 task->tk_action = call_connect;
 814                 return;
 815         }
 816
 817         switch (task->tk_status) {
 818         case -EACCES:
 819                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 820                                 task->tk_pid);
 821                 rpc_delay(task, 3*HZ);
 822                 goto retry_bind;
 823         case -ETIMEDOUT:
 824                 dprintk("RPC: %4d rpcbind request timed out\n",
 825                                 task->tk_pid);
 826                 if (RPC_IS_SOFT(task)) {
 827                         status = -EIO;
 828                         break;
 829                 }
 830                 goto retry_bind;
 831         case -EPFNOSUPPORT:
 832                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 833                                 task->tk_pid);
 834                 break;
 835         case -EPROTONOSUPPORT:
 836                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 837                                 task->tk_pid);
 838                 break;
 839         default:
 840                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 841                                 task->tk_pid, -task->tk_status);
 842                 status = -EIO;
 843                 break;
 844         }
 845
 846         rpc_exit(task, status);
 847         return;
 848
 849 retry_bind:
 850         task->tk_status = 0;
 851         task->tk_action = call_bind;
 852         return;
 853 }
 854
 855 /*
 856  * 4b.  Connect to the RPC server
 857  */
 858 static void
 859 call_connect(struct rpc_task *task)
 860 {
 861         struct rpc_xprt *xprt = task->tk_xprt;
 862
 863         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 864                         task->tk_pid, xprt,
 865                         (xprt_connected(xprt) ? "is" : "is not"));
 866
 867         task->tk_action = call_transmit;
 868         if (!xprt_connected(xprt)) {
 869                 task->tk_action = call_connect_status;
 870                 if (task->tk_status < 0)
 871                         return;
 872                 xprt_connect(task);
 873         }
 874 }
 875
 876 /*
 877  * 4c.  Sort out connect result
 878  */
 879 static void
 880 call_connect_status(struct rpc_task *task)
 881 {
 882         struct rpc_clnt *clnt = task->tk_client;
 883         int status = task->tk_status;
 884
 885         dprintk("RPC: %5u call_connect_status (status %d)\n",
 886                                 task->tk_pid, task->tk_status);
 887
 888         task->tk_status = 0;
 889         if (status >= 0) {
 890                 clnt->cl_stats->netreconn++;
 891                 task->tk_action = call_transmit;
 892                 return;
 893         }
 894
 895         /* Something failed: remote service port may have changed */
 896         rpc_force_rebind(clnt);
 897
 898         switch (status) {
 899         case -ENOTCONN:
 900         case -ETIMEDOUT:
 901         case -EAGAIN:
 902                 task->tk_action = call_bind;
 903                 break;
 904         default:
 905                 rpc_exit(task, -EIO);
 906                 break;
 907         }
 908 }
 909
 910 /*
 911  * 5.   Transmit the RPC request, and wait for reply
 912  */
 913 static void
 914 call_transmit(struct rpc_task *task)
 915 {
 916         dprintk("RPC: %4d call_transmit (status %d)\n",
 917                                 task->tk_pid, task->tk_status);
 918
 919         task->tk_action = call_status;
 920         if (task->tk_status < 0)
 921                 return;
 922         task->tk_status = xprt_prepare_transmit(task);
 923         if (task->tk_status != 0)
 924                 return;
 925         /* Encode here so that rpcsec_gss can use correct sequence number. */
 926         if (rpc_task_need_encode(task)) {
 927                 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                         goto out_nosend;
 932         }
 933         task->tk_action = call_transmit_status;
 934         xprt_transmit(task);
 935         if (task->tk_status < 0)
 936                 return;
 937         if (!task->tk_msg.rpc_proc->p_decode) {
 938                 task->tk_action = rpc_exit_task;
 939                 rpc_wake_up_task(task);
 940         }
 941         return;
 942 out_nosend:
 943         /* release socket write lock before attempting to handle error */
 944         xprt_abort_transmit(task);
 945         rpc_task_force_reencode(task);
 946 }
 947
 948 /*
 949  * 6.   Sort out the RPC call status
 950  */
 951 static void
 952 call_status(struct rpc_task *task)
 953 {
 954         struct rpc_clnt *clnt = task->tk_client;
 955         struct rpc_rqst *req = task->tk_rqstp;
 956         int             status;
 957
 958         if (req->rq_received > 0 && !req->rq_bytes_sent)
 959                 task->tk_status = req->rq_received;
 960
 961         dprintk("RPC: %4d call_status (status %d)\n",
 962                                 task->tk_pid, task->tk_status);
 963
 964         status = task->tk_status;
 965         if (status >= 0) {
 966                 task->tk_action = call_decode;
 967                 return;
 968         }
 969
 970         task->tk_status = 0;
 971         switch(status) {
 972         case -ETIMEDOUT:
 973                 task->tk_action = call_timeout;
 974                 break;
 975         case -ECONNREFUSED:
 976         case -ENOTCONN:
 977                 rpc_force_rebind(clnt);
 978                 task->tk_action = call_bind;
 979                 break;
 980         case -EAGAIN:
 981                 task->tk_action = call_transmit;
 982                 break;
 983         case -EIO:
 984                 /* shutdown or soft timeout */
 985                 rpc_exit(task, status);
 986                 break;
 987         default:
 988                 printk("%s: RPC call returned error %d\n",
 989                                clnt->cl_protname, -status);
 990                 rpc_exit(task, status);
 991                 break;
 992         }
 993 }
 994
 995 /*
 996  * 6a.  Handle transmission errors.
 997  */
 998 static void
 999 call_transmit_status(struct rpc_task *task)
1000 {
1001         if (task->tk_status != -EAGAIN)
1002                 rpc_task_force_reencode(task);
1003         call_status(task);
1004 }
1005
1006 /*
1007  * 6b.  Handle RPC timeout
1008  *      We do not release the request slot, so we keep using the
1009  *      same XID for all retransmits.
1010  */
1011 static void
1012 call_timeout(struct rpc_task *task)
1013 {
1014         struct rpc_clnt *clnt = task->tk_client;
1015
1016         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1017                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1018                 goto retry;
1019         }
1020
1021         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1022         task->tk_timeouts++;
1023
1024         if (RPC_IS_SOFT(task)) {
1025                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1026                                 clnt->cl_protname, clnt->cl_server);
1027                 rpc_exit(task, -EIO);
1028                 return;
1029         }
1030
1031         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1032                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1033                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1034                         clnt->cl_protname, clnt->cl_server);
1035         }
1036         rpc_force_rebind(clnt);
1037
1038 retry:
1039         clnt->cl_stats->rpcretrans++;
1040         task->tk_action = call_bind;
1041         task->tk_status = 0;
1042 }
1043
1044 /*
1045  * 7.   Decode the RPC reply
1046  */
1047 static void
1048 call_decode(struct rpc_task *task)
1049 {
1050         struct rpc_clnt *clnt = task->tk_client;
1051         struct rpc_rqst *req = task->tk_rqstp;
1052         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1053         u32             *p;
1054
1055         dprintk("RPC: %4d call_decode (status %d)\n",
1056                                 task->tk_pid, task->tk_status);
1057
1058         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1059                 printk(KERN_NOTICE "%s: server %s OK\n",
1060                         clnt->cl_protname, clnt->cl_server);
1061                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1062         }
1063
1064         if (task->tk_status < 12) {
1065                 if (!RPC_IS_SOFT(task)) {
1066                         task->tk_action = call_bind;
1067                         clnt->cl_stats->rpcretrans++;
1068                         goto out_retry;
1069                 }
1070                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1071                         clnt->cl_protname, task->tk_status);
1072                 rpc_exit(task, -EIO);
1073                 return;
1074         }
1075
1076         /*
1077          * Ensure that we see all writes made by xprt_complete_rqst()
1078          * before it changed req->rq_received.
1079          */
1080         smp_rmb();
1081         req->rq_rcv_buf.len = req->rq_private_buf.len;
1082
1083         /* Check that the softirq receive buffer is valid */
1084         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1085                                 sizeof(req->rq_rcv_buf)) != 0);
1086
1087         /* Verify the RPC header */
1088         p = call_verify(task);
1089         if (IS_ERR(p)) {
1090                 if (p == ERR_PTR(-EAGAIN))
1091                         goto out_retry;
1092                 return;
1093         }
1094
1095         task->tk_action = rpc_exit_task;
1096
1097         if (decode)
1098                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1099                                                       task->tk_msg.rpc_resp);
1100         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1101                                         task->tk_status);
1102         return;
1103 out_retry:
1104         req->rq_received = req->rq_private_buf.len = 0;
1105         task->tk_status = 0;
1106 }
1107
1108 /*
1109  * 8.   Refresh the credentials if rejected by the server
1110  */
1111 static void
1112 call_refresh(struct rpc_task *task)
1113 {
1114         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1115
1116         xprt_release(task);     /* Must do to obtain new XID */
1117         task->tk_action = call_refreshresult;
1118         task->tk_status = 0;
1119         task->tk_client->cl_stats->rpcauthrefresh++;
1120         rpcauth_refreshcred(task);
1121 }
1122
1123 /*
1124  * 8a.  Process the results of a credential refresh
1125  */
1126 static void
1127 call_refreshresult(struct rpc_task *task)
1128 {
1129         int status = task->tk_status;
1130         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1131                                 task->tk_pid, task->tk_status);
1132
1133         task->tk_status = 0;
1134         task->tk_action = call_reserve;
1135         if (status >= 0 && rpcauth_uptodatecred(task))
1136                 return;
1137         if (status == -EACCES) {
1138                 rpc_exit(task, -EACCES);
1139                 return;
1140         }
1141         task->tk_action = call_refresh;
1142         if (status != -ETIMEDOUT)
1143                 rpc_delay(task, 3*HZ);
1144         return;
1145 }
1146
1147 /*
1148  * Call header serialization
1149  */
1150 static u32 *
1151 call_header(struct rpc_task *task)
1152 {
1153         struct rpc_clnt *clnt = task->tk_client;
1154         struct rpc_rqst *req = task->tk_rqstp;
1155         u32             *p = req->rq_svec[0].iov_base;
1156
1157         /* FIXME: check buffer size? */
1158
1159         p = xprt_skip_transport_header(task->tk_xprt, p);
1160         *p++ = req->rq_xid;             /* XID */
1161         *p++ = htonl(RPC_CALL);         /* CALL */
1162         *p++ = htonl(RPC_VERSION);      /* RPC version */
1163         *p++ = htonl(clnt->cl_prog);    /* program number */
1164         *p++ = htonl(clnt->cl_vers);    /* program version */
1165         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1166         p = rpcauth_marshcred(task, p);
1167         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1168         return p;
1169 }
1170
1171 /*
1172  * Reply header verification
1173  */
1174 static u32 *
1175 call_verify(struct rpc_task *task)
1176 {
1177         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1178         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1179         u32     *p = iov->iov_base, n;
1180         int error = -EACCES;
1181
1182         if ((len -= 3) < 0)
1183                 goto out_overflow;
1184         p += 1; /* skip XID */
1185
1186         if ((n = ntohl(*p++)) != RPC_REPLY) {
1187                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1188                 goto out_garbage;
1189         }
1190         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1191                 if (--len < 0)
1192                         goto out_overflow;
1193                 switch ((n = ntohl(*p++))) {
1194                         case RPC_AUTH_ERROR:
1195                                 break;
1196                         case RPC_MISMATCH:
1197                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1198                                 error = -EPROTONOSUPPORT;
1199                                 goto out_err;
1200                         default:
1201                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1202                                 goto out_eio;
1203                 }
1204                 if (--len < 0)
1205                         goto out_overflow;
1206                 switch ((n = ntohl(*p++))) {
1207                 case RPC_AUTH_REJECTEDCRED:
1208                 case RPC_AUTH_REJECTEDVERF:
1209                 case RPCSEC_GSS_CREDPROBLEM:
1210                 case RPCSEC_GSS_CTXPROBLEM:
1211                         if (!task->tk_cred_retry)
1212                                 break;
1213                         task->tk_cred_retry--;
1214                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1215                                                         task->tk_pid);
1216                         rpcauth_invalcred(task);
1217                         task->tk_action = call_refresh;
1218                         goto out_retry;
1219                 case RPC_AUTH_BADCRED:
1220                 case RPC_AUTH_BADVERF:
1221                         /* possibly garbled cred/verf? */
1222                         if (!task->tk_garb_retry)
1223                                 break;
1224                         task->tk_garb_retry--;
1225                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1226                                                         task->tk_pid);
1227                         task->tk_action = call_bind;
1228                         goto out_retry;
1229                 case RPC_AUTH_TOOWEAK:
1230                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1231                                "authentication.\n", task->tk_client->cl_server);
1232                         break;
1233                 default:
1234                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1235                         error = -EIO;
1236                 }
1237                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1238                                                 task->tk_pid, n);
1239                 goto out_err;
1240         }
1241         if (!(p = rpcauth_checkverf(task, p))) {
1242                 printk(KERN_WARNING "call_verify: auth check failed\n");
1243                 goto out_garbage;               /* bad verifier, retry */
1244         }
1245         len = p - (u32 *)iov->iov_base - 1;
1246         if (len < 0)
1247                 goto out_overflow;
1248         switch ((n = ntohl(*p++))) {
1249         case RPC_SUCCESS:
1250                 return p;
1251         case RPC_PROG_UNAVAIL:
1252                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1253                                 (unsigned int)task->tk_client->cl_prog,
1254                                 task->tk_client->cl_server);
1255                 error = -EPFNOSUPPORT;
1256                 goto out_err;
1257         case RPC_PROG_MISMATCH:
1258                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1259                                 (unsigned int)task->tk_client->cl_prog,
1260                                 (unsigned int)task->tk_client->cl_vers,
1261                                 task->tk_client->cl_server);
1262                 error = -EPROTONOSUPPORT;
1263                 goto out_err;
1264         case RPC_PROC_UNAVAIL:
1265                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1266                                 task->tk_msg.rpc_proc,
1267                                 task->tk_client->cl_prog,
1268                                 task->tk_client->cl_vers,
1269                                 task->tk_client->cl_server);
1270                 error = -EOPNOTSUPP;
1271                 goto out_err;
1272         case RPC_GARBAGE_ARGS:
1273                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1274                 break;                  /* retry */
1275         default:
1276                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1277                 /* Also retry */
1278         }
1279
1280 out_garbage:
1281         task->tk_client->cl_stats->rpcgarbage++;
1282         if (task->tk_garb_retry) {
1283                 task->tk_garb_retry--;
1284                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1285                 task->tk_action = call_bind;
1286 out_retry:
1287                 return ERR_PTR(-EAGAIN);
1288         }
1289         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1290 out_eio:
1291         error = -EIO;
1292 out_err:
1293         rpc_exit(task, error);
1294         return ERR_PTR(error);
1295 out_overflow:
1296         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1297         goto out_garbage;
1298 }
1299
1300 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1301 {
1302         return 0;
1303 }
1304
1305 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1306 {
1307         return 0;
1308 }
1309
1310 static struct rpc_procinfo rpcproc_null = {
1311         .p_encode = rpcproc_encode_null,
1312         .p_decode = rpcproc_decode_null,
1313 };
1314
1315 int rpc_ping(struct rpc_clnt *clnt, int flags)
1316 {
1317         struct rpc_message msg = {
1318                 .rpc_proc = &rpcproc_null,
1319         };
1320         int err;
1321         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1322         err = rpc_call_sync(clnt, &msg, flags);
1323         put_rpccred(msg.rpc_cred);
1324         return err;
1325 }