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/smp_lock.h>
  31 #include <linux/utsname.h>
  32 #include <linux/workqueue.h>
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/rpc_pipe_fs.h>
  36 #include <linux/sunrpc/metrics.h>
  37
  38
  39 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  40
  41 #ifdef RPC_DEBUG
  42 # define RPCDBG_FACILITY        RPCDBG_CALL
  43 #endif
  44
  45 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  46
  47
  48 static void     call_start(struct rpc_task *task);
  49 static void     call_reserve(struct rpc_task *task);
  50 static void     call_reserveresult(struct rpc_task *task);
  51 static void     call_allocate(struct rpc_task *task);
  52 static void     call_encode(struct rpc_task *task);
  53 static void     call_decode(struct rpc_task *task);
  54 static void     call_bind(struct rpc_task *task);
  55 static void     call_bind_status(struct rpc_task *task);
  56 static void     call_transmit(struct rpc_task *task);
  57 static void     call_status(struct rpc_task *task);
  58 static void     call_transmit_status(struct rpc_task *task);
  59 static void     call_refresh(struct rpc_task *task);
  60 static void     call_refreshresult(struct rpc_task *task);
  61 static void     call_timeout(struct rpc_task *task);
  62 static void     call_connect(struct rpc_task *task);
  63 static void     call_connect_status(struct rpc_task *task);
  64 static __be32 * call_header(struct rpc_task *task);
  65 static __be32 * call_verify(struct rpc_task *task);
  66
  67
  68 static int
  69 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  70 {
  71         static uint32_t clntid;
  72         int error;
  73
  74         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  75         clnt->cl_dentry = ERR_PTR(-ENOENT);
  76         if (dir_name == NULL)
  77                 return 0;
  78
  79         clnt->cl_vfsmnt = rpc_get_mount();
  80         if (IS_ERR(clnt->cl_vfsmnt))
  81                 return PTR_ERR(clnt->cl_vfsmnt);
  82
  83         for (;;) {
  84                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  85                                 "%s/clnt%x", dir_name,
  86                                 (unsigned int)clntid++);
  87                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  88                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  89                 if (!IS_ERR(clnt->cl_dentry))
  90                         return 0;
  91                 error = PTR_ERR(clnt->cl_dentry);
  92                 if (error != -EEXIST) {
  93                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  94                                         clnt->cl_pathname, error);
  95                         rpc_put_mount();
  96                         return error;
  97                 }
  98         }
  99 }
 100
 101 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 102 {
 103         struct rpc_version      *version;
 104         struct rpc_clnt         *clnt = NULL;
 105         struct rpc_auth         *auth;
 106         int err;
 107         int len;
 108
 109         dprintk("RPC: creating %s client for %s (xprt %p)\n",
 110                 program->name, servname, xprt);
 111
 112         err = -EINVAL;
 113         if (!xprt)
 114                 goto out_no_xprt;
 115         if (vers >= program->nrvers || !(version = program->version[vers]))
 116                 goto out_err;
 117
 118         err = -ENOMEM;
 119         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 120         if (!clnt)
 121                 goto out_err;
 122         atomic_set(&clnt->cl_users, 0);
 123         atomic_set(&clnt->cl_count, 1);
 124         clnt->cl_parent = clnt;
 125
 126         clnt->cl_server = clnt->cl_inline_name;
 127         len = strlen(servname) + 1;
 128         if (len > sizeof(clnt->cl_inline_name)) {
 129                 char *buf = kmalloc(len, GFP_KERNEL);
 130                 if (buf != 0)
 131                         clnt->cl_server = buf;
 132                 else
 133                         len = sizeof(clnt->cl_inline_name);
 134         }
 135         strlcpy(clnt->cl_server, servname, len);
 136
 137         clnt->cl_xprt     = xprt;
 138         clnt->cl_procinfo = version->procs;
 139         clnt->cl_maxproc  = version->nrprocs;
 140         clnt->cl_protname = program->name;
 141         clnt->cl_prog     = program->number;
 142         clnt->cl_vers     = version->number;
 143         clnt->cl_stats    = program->stats;
 144         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 145         err = -ENOMEM;
 146         if (clnt->cl_metrics == NULL)
 147                 goto out_no_stats;
 148         clnt->cl_program  = program;
 149
 150         if (!xprt_bound(clnt->cl_xprt))
 151                 clnt->cl_autobind = 1;
 152
 153         clnt->cl_rtt = &clnt->cl_rtt_default;
 154         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 155
 156         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 157         if (err < 0)
 158                 goto out_no_path;
 159
 160         auth = rpcauth_create(flavor, clnt);
 161         if (IS_ERR(auth)) {
 162                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 163                                 flavor);
 164                 err = PTR_ERR(auth);
 165                 goto out_no_auth;
 166         }
 167
 168         /* save the nodename */
 169         clnt->cl_nodelen = strlen(utsname()->nodename);
 170         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 171                 clnt->cl_nodelen = UNX_MAXNODENAME;
 172         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 173         return clnt;
 174
 175 out_no_auth:
 176         if (!IS_ERR(clnt->cl_dentry)) {
 177                 rpc_rmdir(clnt->cl_dentry);
 178                 rpc_put_mount();
 179         }
 180 out_no_path:
 181         rpc_free_iostats(clnt->cl_metrics);
 182 out_no_stats:
 183         if (clnt->cl_server != clnt->cl_inline_name)
 184                 kfree(clnt->cl_server);
 185         kfree(clnt);
 186 out_err:
 187         xprt_put(xprt);
 188 out_no_xprt:
 189         return ERR_PTR(err);
 190 }
 191
 192 /*
 193  * rpc_create - create an RPC client and transport with one call
 194  * @args: rpc_clnt create argument structure
 195  *
 196  * Creates and initializes an RPC transport and an RPC client.
 197  *
 198  * It can ping the server in order to determine if it is up, and to see if
 199  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 200  * this behavior so asynchronous tasks can also use rpc_create.
 201  */
 202 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 203 {
 204         struct rpc_xprt *xprt;
 205         struct rpc_clnt *clnt;
 206
 207         xprt = xprt_create_transport(args->protocol, args->address,
 208                                         args->addrsize, args->timeout);
 209         if (IS_ERR(xprt))
 210                 return (struct rpc_clnt *)xprt;
 211
 212         /*
 213          * By default, kernel RPC client connects from a reserved port.
 214          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 215          * but it is always enabled for rpciod, which handles the connect
 216          * operation.
 217          */
 218         xprt->resvport = 1;
 219         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 220                 xprt->resvport = 0;
 221
 222         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 223                 args->program->name, args->servername, xprt);
 224
 225         clnt = rpc_new_client(xprt, args->servername, args->program,
 226                                 args->version, args->authflavor);
 227         if (IS_ERR(clnt))
 228                 return clnt;
 229
 230         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 231                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 232                 if (err != 0) {
 233                         rpc_shutdown_client(clnt);
 234                         return ERR_PTR(err);
 235                 }
 236         }
 237
 238         clnt->cl_softrtry = 1;
 239         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 240                 clnt->cl_softrtry = 0;
 241
 242         if (args->flags & RPC_CLNT_CREATE_INTR)
 243                 clnt->cl_intr = 1;
 244         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 245                 clnt->cl_autobind = 1;
 246         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 247                 clnt->cl_oneshot = 1;
 248
 249         return clnt;
 250 }
 251 EXPORT_SYMBOL_GPL(rpc_create);
 252
 253 /*
 254  * This function clones the RPC client structure. It allows us to share the
 255  * same transport while varying parameters such as the authentication
 256  * flavour.
 257  */
 258 struct rpc_clnt *
 259 rpc_clone_client(struct rpc_clnt *clnt)
 260 {
 261         struct rpc_clnt *new;
 262         int err = -ENOMEM;
 263
 264         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 265         if (!new)
 266                 goto out_no_clnt;
 267         atomic_set(&new->cl_count, 1);
 268         atomic_set(&new->cl_users, 0);
 269         new->cl_metrics = rpc_alloc_iostats(clnt);
 270         if (new->cl_metrics == NULL)
 271                 goto out_no_stats;
 272         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 273         if (err != 0)
 274                 goto out_no_path;
 275         new->cl_parent = clnt;
 276         atomic_inc(&clnt->cl_count);
 277         new->cl_xprt = xprt_get(clnt->cl_xprt);
 278         /* Turn off autobind on clones */
 279         new->cl_autobind = 0;
 280         new->cl_oneshot = 0;
 281         new->cl_dead = 0;
 282         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 283         if (new->cl_auth)
 284                 atomic_inc(&new->cl_auth->au_count);
 285         return new;
 286 out_no_path:
 287         rpc_free_iostats(new->cl_metrics);
 288 out_no_stats:
 289         kfree(new);
 290 out_no_clnt:
 291         dprintk("RPC: %s returned error %d\n", __FUNCTION__, err);
 292         return ERR_PTR(err);
 293 }
 294
 295 /*
 296  * Properly shut down an RPC client, terminating all outstanding
 297  * requests. Note that we must be certain that cl_oneshot and
 298  * cl_dead are cleared, or else the client would be destroyed
 299  * when the last task releases it.
 300  */
 301 int
 302 rpc_shutdown_client(struct rpc_clnt *clnt)
 303 {
 304         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 305                         clnt->cl_protname, clnt->cl_server,
 306                         atomic_read(&clnt->cl_users));
 307
 308         while (atomic_read(&clnt->cl_users) > 0) {
 309                 /* Don't let rpc_release_client destroy us */
 310                 clnt->cl_oneshot = 0;
 311                 clnt->cl_dead = 0;
 312                 rpc_killall_tasks(clnt);
 313                 wait_event_timeout(destroy_wait,
 314                         !atomic_read(&clnt->cl_users), 1*HZ);
 315         }
 316
 317         if (atomic_read(&clnt->cl_users) < 0) {
 318                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 319                                 clnt, atomic_read(&clnt->cl_users));
 320 #ifdef RPC_DEBUG
 321                 rpc_show_tasks();
 322 #endif
 323                 BUG();
 324         }
 325
 326         return rpc_destroy_client(clnt);
 327 }
 328
 329 /*
 330  * Delete an RPC client
 331  */
 332 int
 333 rpc_destroy_client(struct rpc_clnt *clnt)
 334 {
 335         if (!atomic_dec_and_test(&clnt->cl_count))
 336                 return 1;
 337         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 338
 339         dprintk("RPC: destroying %s client for %s\n",
 340                         clnt->cl_protname, clnt->cl_server);
 341         if (clnt->cl_auth) {
 342                 rpcauth_destroy(clnt->cl_auth);
 343                 clnt->cl_auth = NULL;
 344         }
 345         if (!IS_ERR(clnt->cl_dentry)) {
 346                 rpc_rmdir(clnt->cl_dentry);
 347                 rpc_put_mount();
 348         }
 349         if (clnt->cl_parent != clnt) {
 350                 rpc_destroy_client(clnt->cl_parent);
 351                 goto out_free;
 352         }
 353         if (clnt->cl_server != clnt->cl_inline_name)
 354                 kfree(clnt->cl_server);
 355 out_free:
 356         rpc_free_iostats(clnt->cl_metrics);
 357         clnt->cl_metrics = NULL;
 358         xprt_put(clnt->cl_xprt);
 359         kfree(clnt);
 360         return 0;
 361 }
 362
 363 /*
 364  * Release an RPC client
 365  */
 366 void
 367 rpc_release_client(struct rpc_clnt *clnt)
 368 {
 369         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 370                                 clnt, atomic_read(&clnt->cl_users));
 371
 372         if (!atomic_dec_and_test(&clnt->cl_users))
 373                 return;
 374         wake_up(&destroy_wait);
 375         if (clnt->cl_oneshot || clnt->cl_dead)
 376                 rpc_destroy_client(clnt);
 377 }
 378
 379 /**
 380  * rpc_bind_new_program - bind a new RPC program to an existing client
 381  * @old - old rpc_client
 382  * @program - rpc program to set
 383  * @vers - rpc program version
 384  *
 385  * Clones the rpc client and sets up a new RPC program. This is mainly
 386  * of use for enabling different RPC programs to share the same transport.
 387  * The Sun NFSv2/v3 ACL protocol can do this.
 388  */
 389 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 390                                       struct rpc_program *program,
 391                                       int vers)
 392 {
 393         struct rpc_clnt *clnt;
 394         struct rpc_version *version;
 395         int err;
 396
 397         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 398         version = program->version[vers];
 399         clnt = rpc_clone_client(old);
 400         if (IS_ERR(clnt))
 401                 goto out;
 402         clnt->cl_procinfo = version->procs;
 403         clnt->cl_maxproc  = version->nrprocs;
 404         clnt->cl_protname = program->name;
 405         clnt->cl_prog     = program->number;
 406         clnt->cl_vers     = version->number;
 407         clnt->cl_stats    = program->stats;
 408         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 409         if (err != 0) {
 410                 rpc_shutdown_client(clnt);
 411                 clnt = ERR_PTR(err);
 412         }
 413 out:
 414         return clnt;
 415 }
 416
 417 /*
 418  * Default callback for async RPC calls
 419  */
 420 static void
 421 rpc_default_callback(struct rpc_task *task, void *data)
 422 {
 423 }
 424
 425 static const struct rpc_call_ops rpc_default_ops = {
 426         .rpc_call_done = rpc_default_callback,
 427 };
 428
 429 /*
 430  *      Export the signal mask handling for synchronous code that
 431  *      sleeps on RPC calls
 432  */
 433 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 434
 435 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 436 {
 437         unsigned long   sigallow = sigmask(SIGKILL);
 438         sigset_t sigmask;
 439
 440         /* Block all signals except those listed in sigallow */
 441         if (intr)
 442                 sigallow |= RPC_INTR_SIGNALS;
 443         siginitsetinv(&sigmask, sigallow);
 444         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 445 }
 446
 447 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 448 {
 449         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 450 }
 451
 452 static inline void rpc_restore_sigmask(sigset_t *oldset)
 453 {
 454         sigprocmask(SIG_SETMASK, oldset, NULL);
 455 }
 456
 457 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 458 {
 459         rpc_save_sigmask(oldset, clnt->cl_intr);
 460 }
 461
 462 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 463 {
 464         rpc_restore_sigmask(oldset);
 465 }
 466
 467 /*
 468  * New rpc_call implementation
 469  */
 470 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 471 {
 472         struct rpc_task *task;
 473         sigset_t        oldset;
 474         int             status;
 475
 476         /* If this client is slain all further I/O fails */
 477         if (clnt->cl_dead)
 478                 return -EIO;
 479
 480         BUG_ON(flags & RPC_TASK_ASYNC);
 481
 482         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 483         if (task == NULL)
 484                 return -ENOMEM;
 485
 486         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 487         rpc_task_sigmask(task, &oldset);
 488
 489         rpc_call_setup(task, msg, 0);
 490
 491         /* Set up the call info struct and execute the task */
 492         status = task->tk_status;
 493         if (status != 0)
 494                 goto out;
 495         atomic_inc(&task->tk_count);
 496         status = rpc_execute(task);
 497         if (status == 0)
 498                 status = task->tk_status;
 499 out:
 500         rpc_put_task(task);
 501         rpc_restore_sigmask(&oldset);
 502         return status;
 503 }
 504
 505 /*
 506  * New rpc_call implementation
 507  */
 508 int
 509 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 510                const struct rpc_call_ops *tk_ops, void *data)
 511 {
 512         struct rpc_task *task;
 513         sigset_t        oldset;
 514         int             status;
 515
 516         /* If this client is slain all further I/O fails */
 517         status = -EIO;
 518         if (clnt->cl_dead)
 519                 goto out_release;
 520
 521         flags |= RPC_TASK_ASYNC;
 522
 523         /* Create/initialize a new RPC task */
 524         status = -ENOMEM;
 525         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 526                 goto out_release;
 527
 528         /* Mask signals on GSS_AUTH upcalls */
 529         rpc_task_sigmask(task, &oldset);
 530
 531         rpc_call_setup(task, msg, 0);
 532
 533         /* Set up the call info struct and execute the task */
 534         status = task->tk_status;
 535         if (status == 0)
 536                 rpc_execute(task);
 537         else
 538                 rpc_put_task(task);
 539
 540         rpc_restore_sigmask(&oldset);
 541         return status;
 542 out_release:
 543         rpc_release_calldata(tk_ops, data);
 544         return status;
 545 }
 546
 547
 548 void
 549 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 550 {
 551         task->tk_msg   = *msg;
 552         task->tk_flags |= flags;
 553         /* Bind the user cred */
 554         if (task->tk_msg.rpc_cred != NULL)
 555                 rpcauth_holdcred(task);
 556         else
 557                 rpcauth_bindcred(task);
 558
 559         if (task->tk_status == 0)
 560                 task->tk_action = call_start;
 561         else
 562                 task->tk_action = rpc_exit_task;
 563 }
 564
 565 /**
 566  * rpc_peeraddr - extract remote peer address from clnt's xprt
 567  * @clnt: RPC client structure
 568  * @buf: target buffer
 569  * @size: length of target buffer
 570  *
 571  * Returns the number of bytes that are actually in the stored address.
 572  */
 573 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 574 {
 575         size_t bytes;
 576         struct rpc_xprt *xprt = clnt->cl_xprt;
 577
 578         bytes = sizeof(xprt->addr);
 579         if (bytes > bufsize)
 580                 bytes = bufsize;
 581         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 582         return xprt->addrlen;
 583 }
 584 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 585
 586 /**
 587  * rpc_peeraddr2str - return remote peer address in printable format
 588  * @clnt: RPC client structure
 589  * @format: address format
 590  *
 591  */
 592 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 593 {
 594         struct rpc_xprt *xprt = clnt->cl_xprt;
 595
 596         if (xprt->address_strings[format] != NULL)
 597                 return xprt->address_strings[format];
 598         else
 599                 return "unprintable";
 600 }
 601 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 602
 603 void
 604 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 605 {
 606         struct rpc_xprt *xprt = clnt->cl_xprt;
 607         if (xprt->ops->set_buffer_size)
 608                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 609 }
 610
 611 /*
 612  * Return size of largest payload RPC client can support, in bytes
 613  *
 614  * For stream transports, this is one RPC record fragment (see RFC
 615  * 1831), as we don't support multi-record requests yet.  For datagram
 616  * transports, this is the size of an IP packet minus the IP, UDP, and
 617  * RPC header sizes.
 618  */
 619 size_t rpc_max_payload(struct rpc_clnt *clnt)
 620 {
 621         return clnt->cl_xprt->max_payload;
 622 }
 623 EXPORT_SYMBOL_GPL(rpc_max_payload);
 624
 625 /**
 626  * rpc_force_rebind - force transport to check that remote port is unchanged
 627  * @clnt: client to rebind
 628  *
 629  */
 630 void rpc_force_rebind(struct rpc_clnt *clnt)
 631 {
 632         if (clnt->cl_autobind)
 633                 xprt_clear_bound(clnt->cl_xprt);
 634 }
 635 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 636
 637 /*
 638  * Restart an (async) RPC call. Usually called from within the
 639  * exit handler.
 640  */
 641 void
 642 rpc_restart_call(struct rpc_task *task)
 643 {
 644         if (RPC_ASSASSINATED(task))
 645                 return;
 646
 647         task->tk_action = call_start;
 648 }
 649
 650 /*
 651  * 0.  Initial state
 652  *
 653  *     Other FSM states can be visited zero or more times, but
 654  *     this state is visited exactly once for each RPC.
 655  */
 656 static void
 657 call_start(struct rpc_task *task)
 658 {
 659         struct rpc_clnt *clnt = task->tk_client;
 660
 661         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 662                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 663                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 664
 665         /* Increment call count */
 666         task->tk_msg.rpc_proc->p_count++;
 667         clnt->cl_stats->rpccnt++;
 668         task->tk_action = call_reserve;
 669 }
 670
 671 /*
 672  * 1.   Reserve an RPC call slot
 673  */
 674 static void
 675 call_reserve(struct rpc_task *task)
 676 {
 677         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 678
 679         if (!rpcauth_uptodatecred(task)) {
 680                 task->tk_action = call_refresh;
 681                 return;
 682         }
 683
 684         task->tk_status  = 0;
 685         task->tk_action  = call_reserveresult;
 686         xprt_reserve(task);
 687 }
 688
 689 /*
 690  * 1b.  Grok the result of xprt_reserve()
 691  */
 692 static void
 693 call_reserveresult(struct rpc_task *task)
 694 {
 695         int status = task->tk_status;
 696
 697         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 698                                 task->tk_pid, task->tk_status);
 699
 700         /*
 701          * After a call to xprt_reserve(), we must have either
 702          * a request slot or else an error status.
 703          */
 704         task->tk_status = 0;
 705         if (status >= 0) {
 706                 if (task->tk_rqstp) {
 707                         task->tk_action = call_allocate;
 708                         return;
 709                 }
 710
 711                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 712                                 __FUNCTION__, status);
 713                 rpc_exit(task, -EIO);
 714                 return;
 715         }
 716
 717         /*
 718          * Even though there was an error, we may have acquired
 719          * a request slot somehow.  Make sure not to leak it.
 720          */
 721         if (task->tk_rqstp) {
 722                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 723                                 __FUNCTION__, status);
 724                 xprt_release(task);
 725         }
 726
 727         switch (status) {
 728         case -EAGAIN:   /* woken up; retry */
 729                 task->tk_action = call_reserve;
 730                 return;
 731         case -EIO:      /* probably a shutdown */
 732                 break;
 733         default:
 734                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 735                                 __FUNCTION__, status);
 736                 break;
 737         }
 738         rpc_exit(task, status);
 739 }
 740
 741 /*
 742  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 743  *      (Note: buffer memory is freed in xprt_release).
 744  */
 745 static void
 746 call_allocate(struct rpc_task *task)
 747 {
 748         struct rpc_rqst *req = task->tk_rqstp;
 749         struct rpc_xprt *xprt = task->tk_xprt;
 750         unsigned int    bufsiz;
 751
 752         dprintk("RPC: %4d call_allocate (status %d)\n",
 753                                 task->tk_pid, task->tk_status);
 754         task->tk_action = call_bind;
 755         if (req->rq_buffer)
 756                 return;
 757
 758         /* FIXME: compute buffer requirements more exactly using
 759          * auth->au_wslack */
 760         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 761
 762         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 763                 return;
 764         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 765
 766         if (RPC_IS_ASYNC(task) || !signalled()) {
 767                 xprt_release(task);
 768                 task->tk_action = call_reserve;
 769                 rpc_delay(task, HZ>>4);
 770                 return;
 771         }
 772
 773         rpc_exit(task, -ERESTARTSYS);
 774 }
 775
 776 static inline int
 777 rpc_task_need_encode(struct rpc_task *task)
 778 {
 779         return task->tk_rqstp->rq_snd_buf.len == 0;
 780 }
 781
 782 static inline void
 783 rpc_task_force_reencode(struct rpc_task *task)
 784 {
 785         task->tk_rqstp->rq_snd_buf.len = 0;
 786 }
 787
 788 /*
 789  * 3.   Encode arguments of an RPC call
 790  */
 791 static void
 792 call_encode(struct rpc_task *task)
 793 {
 794         struct rpc_rqst *req = task->tk_rqstp;
 795         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 796         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 797         unsigned int    bufsiz;
 798         kxdrproc_t      encode;
 799         __be32          *p;
 800
 801         dprintk("RPC: %4d call_encode (status %d)\n",
 802                                 task->tk_pid, task->tk_status);
 803
 804         /* Default buffer setup */
 805         bufsiz = req->rq_bufsize >> 1;
 806         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 807         sndbuf->head[0].iov_len  = bufsiz;
 808         sndbuf->tail[0].iov_len  = 0;
 809         sndbuf->page_len         = 0;
 810         sndbuf->len              = 0;
 811         sndbuf->buflen           = bufsiz;
 812         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 813         rcvbuf->head[0].iov_len  = bufsiz;
 814         rcvbuf->tail[0].iov_len  = 0;
 815         rcvbuf->page_len         = 0;
 816         rcvbuf->len              = 0;
 817         rcvbuf->buflen           = bufsiz;
 818
 819         /* Encode header and provided arguments */
 820         encode = task->tk_msg.rpc_proc->p_encode;
 821         if (!(p = call_header(task))) {
 822                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 823                 rpc_exit(task, -EIO);
 824                 return;
 825         }
 826         if (encode == NULL)
 827                 return;
 828
 829         lock_kernel();
 830         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 831                         task->tk_msg.rpc_argp);
 832         unlock_kernel();
 833         if (task->tk_status == -ENOMEM) {
 834                 /* XXX: Is this sane? */
 835                 rpc_delay(task, 3*HZ);
 836                 task->tk_status = -EAGAIN;
 837         }
 838 }
 839
 840 /*
 841  * 4.   Get the server port number if not yet set
 842  */
 843 static void
 844 call_bind(struct rpc_task *task)
 845 {
 846         struct rpc_xprt *xprt = task->tk_xprt;
 847
 848         dprintk("RPC: %4d call_bind (status %d)\n",
 849                                 task->tk_pid, task->tk_status);
 850
 851         task->tk_action = call_connect;
 852         if (!xprt_bound(xprt)) {
 853                 task->tk_action = call_bind_status;
 854                 task->tk_timeout = xprt->bind_timeout;
 855                 xprt->ops->rpcbind(task);
 856         }
 857 }
 858
 859 /*
 860  * 4a.  Sort out bind result
 861  */
 862 static void
 863 call_bind_status(struct rpc_task *task)
 864 {
 865         int status = -EACCES;
 866
 867         if (task->tk_status >= 0) {
 868                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 869                                         task->tk_pid, task->tk_status);
 870                 task->tk_status = 0;
 871                 task->tk_action = call_connect;
 872                 return;
 873         }
 874
 875         switch (task->tk_status) {
 876         case -EACCES:
 877                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 878                                 task->tk_pid);
 879                 rpc_delay(task, 3*HZ);
 880                 goto retry_timeout;
 881         case -ETIMEDOUT:
 882                 dprintk("RPC: %4d rpcbind request timed out\n",
 883                                 task->tk_pid);
 884                 goto retry_timeout;
 885         case -EPFNOSUPPORT:
 886                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 887                                 task->tk_pid);
 888                 break;
 889         case -EPROTONOSUPPORT:
 890                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 891                                 task->tk_pid);
 892                 break;
 893         default:
 894                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 895                                 task->tk_pid, -task->tk_status);
 896                 status = -EIO;
 897         }
 898
 899         rpc_exit(task, status);
 900         return;
 901
 902 retry_timeout:
 903         task->tk_action = call_timeout;
 904 }
 905
 906 /*
 907  * 4b.  Connect to the RPC server
 908  */
 909 static void
 910 call_connect(struct rpc_task *task)
 911 {
 912         struct rpc_xprt *xprt = task->tk_xprt;
 913
 914         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 915                         task->tk_pid, xprt,
 916                         (xprt_connected(xprt) ? "is" : "is not"));
 917
 918         task->tk_action = call_transmit;
 919         if (!xprt_connected(xprt)) {
 920                 task->tk_action = call_connect_status;
 921                 if (task->tk_status < 0)
 922                         return;
 923                 xprt_connect(task);
 924         }
 925 }
 926
 927 /*
 928  * 4c.  Sort out connect result
 929  */
 930 static void
 931 call_connect_status(struct rpc_task *task)
 932 {
 933         struct rpc_clnt *clnt = task->tk_client;
 934         int status = task->tk_status;
 935
 936         dprintk("RPC: %5u call_connect_status (status %d)\n",
 937                                 task->tk_pid, task->tk_status);
 938
 939         task->tk_status = 0;
 940         if (status >= 0) {
 941                 clnt->cl_stats->netreconn++;
 942                 task->tk_action = call_transmit;
 943                 return;
 944         }
 945
 946         /* Something failed: remote service port may have changed */
 947         rpc_force_rebind(clnt);
 948
 949         switch (status) {
 950         case -ENOTCONN:
 951         case -EAGAIN:
 952                 task->tk_action = call_bind;
 953                 if (!RPC_IS_SOFT(task))
 954                         return;
 955                 /* if soft mounted, test if we've timed out */
 956         case -ETIMEDOUT:
 957                 task->tk_action = call_timeout;
 958                 return;
 959         }
 960         rpc_exit(task, -EIO);
 961 }
 962
 963 /*
 964  * 5.   Transmit the RPC request, and wait for reply
 965  */
 966 static void
 967 call_transmit(struct rpc_task *task)
 968 {
 969         dprintk("RPC: %4d call_transmit (status %d)\n",
 970                                 task->tk_pid, task->tk_status);
 971
 972         task->tk_action = call_status;
 973         if (task->tk_status < 0)
 974                 return;
 975         task->tk_status = xprt_prepare_transmit(task);
 976         if (task->tk_status != 0)
 977                 return;
 978         task->tk_action = call_transmit_status;
 979         /* Encode here so that rpcsec_gss can use correct sequence number. */
 980         if (rpc_task_need_encode(task)) {
 981                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 982                 call_encode(task);
 983                 /* Did the encode result in an error condition? */
 984                 if (task->tk_status != 0)
 985                         return;
 986         }
 987         xprt_transmit(task);
 988         if (task->tk_status < 0)
 989                 return;
 990         /*
 991          * On success, ensure that we call xprt_end_transmit() before sleeping
 992          * in order to allow access to the socket to other RPC requests.
 993          */
 994         call_transmit_status(task);
 995         if (task->tk_msg.rpc_proc->p_decode != NULL)
 996                 return;
 997         task->tk_action = rpc_exit_task;
 998         rpc_wake_up_task(task);
 999 }
1000
1001 /*
1002  * 5a.  Handle cleanup after a transmission
1003  */
1004 static void
1005 call_transmit_status(struct rpc_task *task)
1006 {
1007         task->tk_action = call_status;
1008         /*
1009          * Special case: if we've been waiting on the socket's write_space()
1010          * callback, then don't call xprt_end_transmit().
1011          */
1012         if (task->tk_status == -EAGAIN)
1013                 return;
1014         xprt_end_transmit(task);
1015         rpc_task_force_reencode(task);
1016 }
1017
1018 /*
1019  * 6.   Sort out the RPC call status
1020  */
1021 static void
1022 call_status(struct rpc_task *task)
1023 {
1024         struct rpc_clnt *clnt = task->tk_client;
1025         struct rpc_rqst *req = task->tk_rqstp;
1026         int             status;
1027
1028         if (req->rq_received > 0 && !req->rq_bytes_sent)
1029                 task->tk_status = req->rq_received;
1030
1031         dprintk("RPC: %4d call_status (status %d)\n",
1032                                 task->tk_pid, task->tk_status);
1033
1034         status = task->tk_status;
1035         if (status >= 0) {
1036                 task->tk_action = call_decode;
1037                 return;
1038         }
1039
1040         task->tk_status = 0;
1041         switch(status) {
1042         case -EHOSTDOWN:
1043         case -EHOSTUNREACH:
1044         case -ENETUNREACH:
1045                 /*
1046                  * Delay any retries for 3 seconds, then handle as if it
1047                  * were a timeout.
1048                  */
1049                 rpc_delay(task, 3*HZ);
1050         case -ETIMEDOUT:
1051                 task->tk_action = call_timeout;
1052                 break;
1053         case -ECONNREFUSED:
1054         case -ENOTCONN:
1055                 rpc_force_rebind(clnt);
1056                 task->tk_action = call_bind;
1057                 break;
1058         case -EAGAIN:
1059                 task->tk_action = call_transmit;
1060                 break;
1061         case -EIO:
1062                 /* shutdown or soft timeout */
1063                 rpc_exit(task, status);
1064                 break;
1065         default:
1066                 printk("%s: RPC call returned error %d\n",
1067                                clnt->cl_protname, -status);
1068                 rpc_exit(task, status);
1069         }
1070 }
1071
1072 /*
1073  * 6a.  Handle RPC timeout
1074  *      We do not release the request slot, so we keep using the
1075  *      same XID for all retransmits.
1076  */
1077 static void
1078 call_timeout(struct rpc_task *task)
1079 {
1080         struct rpc_clnt *clnt = task->tk_client;
1081
1082         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1083                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1084                 goto retry;
1085         }
1086
1087         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1088         task->tk_timeouts++;
1089
1090         if (RPC_IS_SOFT(task)) {
1091                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1092                                 clnt->cl_protname, clnt->cl_server);
1093                 rpc_exit(task, -EIO);
1094                 return;
1095         }
1096
1097         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1098                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1099                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1100                         clnt->cl_protname, clnt->cl_server);
1101         }
1102         rpc_force_rebind(clnt);
1103
1104 retry:
1105         clnt->cl_stats->rpcretrans++;
1106         task->tk_action = call_bind;
1107         task->tk_status = 0;
1108 }
1109
1110 /*
1111  * 7.   Decode the RPC reply
1112  */
1113 static void
1114 call_decode(struct rpc_task *task)
1115 {
1116         struct rpc_clnt *clnt = task->tk_client;
1117         struct rpc_rqst *req = task->tk_rqstp;
1118         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1119         __be32          *p;
1120
1121         dprintk("RPC: %4d call_decode (status %d)\n",
1122                                 task->tk_pid, task->tk_status);
1123
1124         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1125                 printk(KERN_NOTICE "%s: server %s OK\n",
1126                         clnt->cl_protname, clnt->cl_server);
1127                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1128         }
1129
1130         if (task->tk_status < 12) {
1131                 if (!RPC_IS_SOFT(task)) {
1132                         task->tk_action = call_bind;
1133                         clnt->cl_stats->rpcretrans++;
1134                         goto out_retry;
1135                 }
1136                 dprintk("%s: too small RPC reply size (%d bytes)\n",
1137                         clnt->cl_protname, task->tk_status);
1138                 task->tk_action = call_timeout;
1139                 goto out_retry;
1140         }
1141
1142         /*
1143          * Ensure that we see all writes made by xprt_complete_rqst()
1144          * before it changed req->rq_received.
1145          */
1146         smp_rmb();
1147         req->rq_rcv_buf.len = req->rq_private_buf.len;
1148
1149         /* Check that the softirq receive buffer is valid */
1150         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1151                                 sizeof(req->rq_rcv_buf)) != 0);
1152
1153         /* Verify the RPC header */
1154         p = call_verify(task);
1155         if (IS_ERR(p)) {
1156                 if (p == ERR_PTR(-EAGAIN))
1157                         goto out_retry;
1158                 return;
1159         }
1160
1161         task->tk_action = rpc_exit_task;
1162
1163         if (decode) {
1164                 lock_kernel();
1165                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1166                                                       task->tk_msg.rpc_resp);
1167                 unlock_kernel();
1168         }
1169         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1170                                         task->tk_status);
1171         return;
1172 out_retry:
1173         req->rq_received = req->rq_private_buf.len = 0;
1174         task->tk_status = 0;
1175 }
1176
1177 /*
1178  * 8.   Refresh the credentials if rejected by the server
1179  */
1180 static void
1181 call_refresh(struct rpc_task *task)
1182 {
1183         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1184
1185         xprt_release(task);     /* Must do to obtain new XID */
1186         task->tk_action = call_refreshresult;
1187         task->tk_status = 0;
1188         task->tk_client->cl_stats->rpcauthrefresh++;
1189         rpcauth_refreshcred(task);
1190 }
1191
1192 /*
1193  * 8a.  Process the results of a credential refresh
1194  */
1195 static void
1196 call_refreshresult(struct rpc_task *task)
1197 {
1198         int status = task->tk_status;
1199         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1200                                 task->tk_pid, task->tk_status);
1201
1202         task->tk_status = 0;
1203         task->tk_action = call_reserve;
1204         if (status >= 0 && rpcauth_uptodatecred(task))
1205                 return;
1206         if (status == -EACCES) {
1207                 rpc_exit(task, -EACCES);
1208                 return;
1209         }
1210         task->tk_action = call_refresh;
1211         if (status != -ETIMEDOUT)
1212                 rpc_delay(task, 3*HZ);
1213         return;
1214 }
1215
1216 /*
1217  * Call header serialization
1218  */
1219 static __be32 *
1220 call_header(struct rpc_task *task)
1221 {
1222         struct rpc_clnt *clnt = task->tk_client;
1223         struct rpc_rqst *req = task->tk_rqstp;
1224         __be32          *p = req->rq_svec[0].iov_base;
1225
1226         /* FIXME: check buffer size? */
1227
1228         p = xprt_skip_transport_header(task->tk_xprt, p);
1229         *p++ = req->rq_xid;             /* XID */
1230         *p++ = htonl(RPC_CALL);         /* CALL */
1231         *p++ = htonl(RPC_VERSION);      /* RPC version */
1232         *p++ = htonl(clnt->cl_prog);    /* program number */
1233         *p++ = htonl(clnt->cl_vers);    /* program version */
1234         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1235         p = rpcauth_marshcred(task, p);
1236         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1237         return p;
1238 }
1239
1240 /*
1241  * Reply header verification
1242  */
1243 static __be32 *
1244 call_verify(struct rpc_task *task)
1245 {
1246         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1247         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1248         __be32  *p = iov->iov_base;
1249         u32 n;
1250         int error = -EACCES;
1251
1252         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1253                 /* RFC-1014 says that the representation of XDR data must be a
1254                  * multiple of four bytes
1255                  * - if it isn't pointer subtraction in the NFS client may give
1256                  *   undefined results
1257                  */
1258                 printk(KERN_WARNING
1259                        "call_verify: XDR representation not a multiple of"
1260                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1261                 goto out_eio;
1262         }
1263         if ((len -= 3) < 0)
1264                 goto out_overflow;
1265         p += 1; /* skip XID */
1266
1267         if ((n = ntohl(*p++)) != RPC_REPLY) {
1268                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1269                 goto out_garbage;
1270         }
1271         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1272                 if (--len < 0)
1273                         goto out_overflow;
1274                 switch ((n = ntohl(*p++))) {
1275                         case RPC_AUTH_ERROR:
1276                                 break;
1277                         case RPC_MISMATCH:
1278                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1279                                 error = -EPROTONOSUPPORT;
1280                                 goto out_err;
1281                         default:
1282                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1283                                 goto out_eio;
1284                 }
1285                 if (--len < 0)
1286                         goto out_overflow;
1287                 switch ((n = ntohl(*p++))) {
1288                 case RPC_AUTH_REJECTEDCRED:
1289                 case RPC_AUTH_REJECTEDVERF:
1290                 case RPCSEC_GSS_CREDPROBLEM:
1291                 case RPCSEC_GSS_CTXPROBLEM:
1292                         if (!task->tk_cred_retry)
1293                                 break;
1294                         task->tk_cred_retry--;
1295                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1296                                                         task->tk_pid);
1297                         rpcauth_invalcred(task);
1298                         task->tk_action = call_refresh;
1299                         goto out_retry;
1300                 case RPC_AUTH_BADCRED:
1301                 case RPC_AUTH_BADVERF:
1302                         /* possibly garbled cred/verf? */
1303                         if (!task->tk_garb_retry)
1304                                 break;
1305                         task->tk_garb_retry--;
1306                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1307                                                         task->tk_pid);
1308                         task->tk_action = call_bind;
1309                         goto out_retry;
1310                 case RPC_AUTH_TOOWEAK:
1311                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1312                                "authentication.\n", task->tk_client->cl_server);
1313                         break;
1314                 default:
1315                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1316                         error = -EIO;
1317                 }
1318                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1319                                                 task->tk_pid, n);
1320                 goto out_err;
1321         }
1322         if (!(p = rpcauth_checkverf(task, p))) {
1323                 printk(KERN_WARNING "call_verify: auth check failed\n");
1324                 goto out_garbage;               /* bad verifier, retry */
1325         }
1326         len = p - (__be32 *)iov->iov_base - 1;
1327         if (len < 0)
1328                 goto out_overflow;
1329         switch ((n = ntohl(*p++))) {
1330         case RPC_SUCCESS:
1331                 return p;
1332         case RPC_PROG_UNAVAIL:
1333                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1334                                 (unsigned int)task->tk_client->cl_prog,
1335                                 task->tk_client->cl_server);
1336                 error = -EPFNOSUPPORT;
1337                 goto out_err;
1338         case RPC_PROG_MISMATCH:
1339                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1340                                 (unsigned int)task->tk_client->cl_prog,
1341                                 (unsigned int)task->tk_client->cl_vers,
1342                                 task->tk_client->cl_server);
1343                 error = -EPROTONOSUPPORT;
1344                 goto out_err;
1345         case RPC_PROC_UNAVAIL:
1346                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1347                                 task->tk_msg.rpc_proc,
1348                                 task->tk_client->cl_prog,
1349                                 task->tk_client->cl_vers,
1350                                 task->tk_client->cl_server);
1351                 error = -EOPNOTSUPP;
1352                 goto out_err;
1353         case RPC_GARBAGE_ARGS:
1354                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1355                 break;                  /* retry */
1356         default:
1357                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1358                 /* Also retry */
1359         }
1360
1361 out_garbage:
1362         task->tk_client->cl_stats->rpcgarbage++;
1363         if (task->tk_garb_retry) {
1364                 task->tk_garb_retry--;
1365                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1366                 task->tk_action = call_bind;
1367 out_retry:
1368                 return ERR_PTR(-EAGAIN);
1369         }
1370         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1371 out_eio:
1372         error = -EIO;
1373 out_err:
1374         rpc_exit(task, error);
1375         return ERR_PTR(error);
1376 out_overflow:
1377         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1378         goto out_garbage;
1379 }
1380
1381 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1382 {
1383         return 0;
1384 }
1385
1386 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1387 {
1388         return 0;
1389 }
1390
1391 static struct rpc_procinfo rpcproc_null = {
1392         .p_encode = rpcproc_encode_null,
1393         .p_decode = rpcproc_decode_null,
1394 };
1395
1396 int rpc_ping(struct rpc_clnt *clnt, int flags)
1397 {
1398         struct rpc_message msg = {
1399                 .rpc_proc = &rpcproc_null,
1400         };
1401         int err;
1402         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1403         err = rpc_call_sync(clnt, &msg, flags);
1404         put_rpccred(msg.rpc_cred);
1405         return err;
1406 }