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/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                 rpc_release_task(task);
 495                 goto out;
 496         }
 497         atomic_inc(&task->tk_count);
 498         status = rpc_execute(task);
 499         if (status == 0)
 500                 status = task->tk_status;
 501         rpc_put_task(task);
 502 out:
 503         rpc_restore_sigmask(&oldset);
 504         return status;
 505 }
 506
 507 /*
 508  * New rpc_call implementation
 509  */
 510 int
 511 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 512                const struct rpc_call_ops *tk_ops, void *data)
 513 {
 514         struct rpc_task *task;
 515         sigset_t        oldset;
 516         int             status;
 517
 518         /* If this client is slain all further I/O fails */
 519         status = -EIO;
 520         if (clnt->cl_dead)
 521                 goto out_release;
 522
 523         flags |= RPC_TASK_ASYNC;
 524
 525         /* Create/initialize a new RPC task */
 526         status = -ENOMEM;
 527         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 528                 goto out_release;
 529
 530         /* Mask signals on GSS_AUTH upcalls */
 531         rpc_task_sigmask(task, &oldset);
 532
 533         rpc_call_setup(task, msg, 0);
 534
 535         /* Set up the call info struct and execute the task */
 536         status = task->tk_status;
 537         if (status == 0)
 538                 rpc_execute(task);
 539         else
 540                 rpc_release_task(task);
 541
 542         rpc_restore_sigmask(&oldset);
 543         return status;
 544 out_release:
 545         rpc_release_calldata(tk_ops, data);
 546         return status;
 547 }
 548
 549
 550 void
 551 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 552 {
 553         task->tk_msg   = *msg;
 554         task->tk_flags |= flags;
 555         /* Bind the user cred */
 556         if (task->tk_msg.rpc_cred != NULL)
 557                 rpcauth_holdcred(task);
 558         else
 559                 rpcauth_bindcred(task);
 560
 561         if (task->tk_status == 0)
 562                 task->tk_action = call_start;
 563         else
 564                 task->tk_action = rpc_exit_task;
 565 }
 566
 567 /**
 568  * rpc_peeraddr - extract remote peer address from clnt's xprt
 569  * @clnt: RPC client structure
 570  * @buf: target buffer
 571  * @size: length of target buffer
 572  *
 573  * Returns the number of bytes that are actually in the stored address.
 574  */
 575 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 576 {
 577         size_t bytes;
 578         struct rpc_xprt *xprt = clnt->cl_xprt;
 579
 580         bytes = sizeof(xprt->addr);
 581         if (bytes > bufsize)
 582                 bytes = bufsize;
 583         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 584         return xprt->addrlen;
 585 }
 586 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 587
 588 /**
 589  * rpc_peeraddr2str - return remote peer address in printable format
 590  * @clnt: RPC client structure
 591  * @format: address format
 592  *
 593  */
 594 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 595 {
 596         struct rpc_xprt *xprt = clnt->cl_xprt;
 597
 598         if (xprt->address_strings[format] != NULL)
 599                 return xprt->address_strings[format];
 600         else
 601                 return "unprintable";
 602 }
 603 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 604
 605 void
 606 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 607 {
 608         struct rpc_xprt *xprt = clnt->cl_xprt;
 609         if (xprt->ops->set_buffer_size)
 610                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 611 }
 612
 613 /*
 614  * Return size of largest payload RPC client can support, in bytes
 615  *
 616  * For stream transports, this is one RPC record fragment (see RFC
 617  * 1831), as we don't support multi-record requests yet.  For datagram
 618  * transports, this is the size of an IP packet minus the IP, UDP, and
 619  * RPC header sizes.
 620  */
 621 size_t rpc_max_payload(struct rpc_clnt *clnt)
 622 {
 623         return clnt->cl_xprt->max_payload;
 624 }
 625 EXPORT_SYMBOL_GPL(rpc_max_payload);
 626
 627 /**
 628  * rpc_force_rebind - force transport to check that remote port is unchanged
 629  * @clnt: client to rebind
 630  *
 631  */
 632 void rpc_force_rebind(struct rpc_clnt *clnt)
 633 {
 634         if (clnt->cl_autobind)
 635                 xprt_clear_bound(clnt->cl_xprt);
 636 }
 637 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 638
 639 /*
 640  * Restart an (async) RPC call. Usually called from within the
 641  * exit handler.
 642  */
 643 void
 644 rpc_restart_call(struct rpc_task *task)
 645 {
 646         if (RPC_ASSASSINATED(task))
 647                 return;
 648
 649         task->tk_action = call_start;
 650 }
 651
 652 /*
 653  * 0.  Initial state
 654  *
 655  *     Other FSM states can be visited zero or more times, but
 656  *     this state is visited exactly once for each RPC.
 657  */
 658 static void
 659 call_start(struct rpc_task *task)
 660 {
 661         struct rpc_clnt *clnt = task->tk_client;
 662
 663         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 664                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 665                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 666
 667         /* Increment call count */
 668         task->tk_msg.rpc_proc->p_count++;
 669         clnt->cl_stats->rpccnt++;
 670         task->tk_action = call_reserve;
 671 }
 672
 673 /*
 674  * 1.   Reserve an RPC call slot
 675  */
 676 static void
 677 call_reserve(struct rpc_task *task)
 678 {
 679         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 680
 681         if (!rpcauth_uptodatecred(task)) {
 682                 task->tk_action = call_refresh;
 683                 return;
 684         }
 685
 686         task->tk_status  = 0;
 687         task->tk_action  = call_reserveresult;
 688         xprt_reserve(task);
 689 }
 690
 691 /*
 692  * 1b.  Grok the result of xprt_reserve()
 693  */
 694 static void
 695 call_reserveresult(struct rpc_task *task)
 696 {
 697         int status = task->tk_status;
 698
 699         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 700                                 task->tk_pid, task->tk_status);
 701
 702         /*
 703          * After a call to xprt_reserve(), we must have either
 704          * a request slot or else an error status.
 705          */
 706         task->tk_status = 0;
 707         if (status >= 0) {
 708                 if (task->tk_rqstp) {
 709                         task->tk_action = call_allocate;
 710                         return;
 711                 }
 712
 713                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 714                                 __FUNCTION__, status);
 715                 rpc_exit(task, -EIO);
 716                 return;
 717         }
 718
 719         /*
 720          * Even though there was an error, we may have acquired
 721          * a request slot somehow.  Make sure not to leak it.
 722          */
 723         if (task->tk_rqstp) {
 724                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 725                                 __FUNCTION__, status);
 726                 xprt_release(task);
 727         }
 728
 729         switch (status) {
 730         case -EAGAIN:   /* woken up; retry */
 731                 task->tk_action = call_reserve;
 732                 return;
 733         case -EIO:      /* probably a shutdown */
 734                 break;
 735         default:
 736                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 737                                 __FUNCTION__, status);
 738                 break;
 739         }
 740         rpc_exit(task, status);
 741 }
 742
 743 /*
 744  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 745  *      (Note: buffer memory is freed in xprt_release).
 746  */
 747 static void
 748 call_allocate(struct rpc_task *task)
 749 {
 750         struct rpc_rqst *req = task->tk_rqstp;
 751         struct rpc_xprt *xprt = task->tk_xprt;
 752         unsigned int    bufsiz;
 753
 754         dprintk("RPC: %4d call_allocate (status %d)\n",
 755                                 task->tk_pid, task->tk_status);
 756         task->tk_action = call_bind;
 757         if (req->rq_buffer)
 758                 return;
 759
 760         /* FIXME: compute buffer requirements more exactly using
 761          * auth->au_wslack */
 762         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 763
 764         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 765                 return;
 766         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 767
 768         if (RPC_IS_ASYNC(task) || !signalled()) {
 769                 xprt_release(task);
 770                 task->tk_action = call_reserve;
 771                 rpc_delay(task, HZ>>4);
 772                 return;
 773         }
 774
 775         rpc_exit(task, -ERESTARTSYS);
 776 }
 777
 778 static inline int
 779 rpc_task_need_encode(struct rpc_task *task)
 780 {
 781         return task->tk_rqstp->rq_snd_buf.len == 0;
 782 }
 783
 784 static inline void
 785 rpc_task_force_reencode(struct rpc_task *task)
 786 {
 787         task->tk_rqstp->rq_snd_buf.len = 0;
 788 }
 789
 790 /*
 791  * 3.   Encode arguments of an RPC call
 792  */
 793 static void
 794 call_encode(struct rpc_task *task)
 795 {
 796         struct rpc_rqst *req = task->tk_rqstp;
 797         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 798         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 799         unsigned int    bufsiz;
 800         kxdrproc_t      encode;
 801         __be32          *p;
 802
 803         dprintk("RPC: %4d call_encode (status %d)\n",
 804                                 task->tk_pid, task->tk_status);
 805
 806         /* Default buffer setup */
 807         bufsiz = req->rq_bufsize >> 1;
 808         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 809         sndbuf->head[0].iov_len  = bufsiz;
 810         sndbuf->tail[0].iov_len  = 0;
 811         sndbuf->page_len         = 0;
 812         sndbuf->len              = 0;
 813         sndbuf->buflen           = bufsiz;
 814         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 815         rcvbuf->head[0].iov_len  = bufsiz;
 816         rcvbuf->tail[0].iov_len  = 0;
 817         rcvbuf->page_len         = 0;
 818         rcvbuf->len              = 0;
 819         rcvbuf->buflen           = bufsiz;
 820
 821         /* Encode header and provided arguments */
 822         encode = task->tk_msg.rpc_proc->p_encode;
 823         if (!(p = call_header(task))) {
 824                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 825                 rpc_exit(task, -EIO);
 826                 return;
 827         }
 828         if (encode == NULL)
 829                 return;
 830
 831         lock_kernel();
 832         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 833                         task->tk_msg.rpc_argp);
 834         unlock_kernel();
 835         if (task->tk_status == -ENOMEM) {
 836                 /* XXX: Is this sane? */
 837                 rpc_delay(task, 3*HZ);
 838                 task->tk_status = -EAGAIN;
 839         }
 840 }
 841
 842 /*
 843  * 4.   Get the server port number if not yet set
 844  */
 845 static void
 846 call_bind(struct rpc_task *task)
 847 {
 848         struct rpc_xprt *xprt = task->tk_xprt;
 849
 850         dprintk("RPC: %4d call_bind (status %d)\n",
 851                                 task->tk_pid, task->tk_status);
 852
 853         task->tk_action = call_connect;
 854         if (!xprt_bound(xprt)) {
 855                 task->tk_action = call_bind_status;
 856                 task->tk_timeout = xprt->bind_timeout;
 857                 xprt->ops->rpcbind(task);
 858         }
 859 }
 860
 861 /*
 862  * 4a.  Sort out bind result
 863  */
 864 static void
 865 call_bind_status(struct rpc_task *task)
 866 {
 867         int status = -EACCES;
 868
 869         if (task->tk_status >= 0) {
 870                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 871                                         task->tk_pid, task->tk_status);
 872                 task->tk_status = 0;
 873                 task->tk_action = call_connect;
 874                 return;
 875         }
 876
 877         switch (task->tk_status) {
 878         case -EACCES:
 879                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 880                                 task->tk_pid);
 881                 rpc_delay(task, 3*HZ);
 882                 goto retry_timeout;
 883         case -ETIMEDOUT:
 884                 dprintk("RPC: %4d rpcbind request timed out\n",
 885                                 task->tk_pid);
 886                 goto retry_timeout;
 887         case -EPFNOSUPPORT:
 888                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 889                                 task->tk_pid);
 890                 break;
 891         case -EPROTONOSUPPORT:
 892                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 893                                 task->tk_pid);
 894                 break;
 895         default:
 896                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 897                                 task->tk_pid, -task->tk_status);
 898                 status = -EIO;
 899         }
 900
 901         rpc_exit(task, status);
 902         return;
 903
 904 retry_timeout:
 905         task->tk_action = call_timeout;
 906 }
 907
 908 /*
 909  * 4b.  Connect to the RPC server
 910  */
 911 static void
 912 call_connect(struct rpc_task *task)
 913 {
 914         struct rpc_xprt *xprt = task->tk_xprt;
 915
 916         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 917                         task->tk_pid, xprt,
 918                         (xprt_connected(xprt) ? "is" : "is not"));
 919
 920         task->tk_action = call_transmit;
 921         if (!xprt_connected(xprt)) {
 922                 task->tk_action = call_connect_status;
 923                 if (task->tk_status < 0)
 924                         return;
 925                 xprt_connect(task);
 926         }
 927 }
 928
 929 /*
 930  * 4c.  Sort out connect result
 931  */
 932 static void
 933 call_connect_status(struct rpc_task *task)
 934 {
 935         struct rpc_clnt *clnt = task->tk_client;
 936         int status = task->tk_status;
 937
 938         dprintk("RPC: %5u call_connect_status (status %d)\n",
 939                                 task->tk_pid, task->tk_status);
 940
 941         task->tk_status = 0;
 942         if (status >= 0) {
 943                 clnt->cl_stats->netreconn++;
 944                 task->tk_action = call_transmit;
 945                 return;
 946         }
 947
 948         /* Something failed: remote service port may have changed */
 949         rpc_force_rebind(clnt);
 950
 951         switch (status) {
 952         case -ENOTCONN:
 953         case -EAGAIN:
 954                 task->tk_action = call_bind;
 955                 if (!RPC_IS_SOFT(task))
 956                         return;
 957                 /* if soft mounted, test if we've timed out */
 958         case -ETIMEDOUT:
 959                 task->tk_action = call_timeout;
 960                 return;
 961         }
 962         rpc_exit(task, -EIO);
 963 }
 964
 965 /*
 966  * 5.   Transmit the RPC request, and wait for reply
 967  */
 968 static void
 969 call_transmit(struct rpc_task *task)
 970 {
 971         dprintk("RPC: %4d call_transmit (status %d)\n",
 972                                 task->tk_pid, task->tk_status);
 973
 974         task->tk_action = call_status;
 975         if (task->tk_status < 0)
 976                 return;
 977         task->tk_status = xprt_prepare_transmit(task);
 978         if (task->tk_status != 0)
 979                 return;
 980         task->tk_action = call_transmit_status;
 981         /* Encode here so that rpcsec_gss can use correct sequence number. */
 982         if (rpc_task_need_encode(task)) {
 983                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 984                 call_encode(task);
 985                 /* Did the encode result in an error condition? */
 986                 if (task->tk_status != 0)
 987                         return;
 988         }
 989         xprt_transmit(task);
 990         if (task->tk_status < 0)
 991                 return;
 992         /*
 993          * On success, ensure that we call xprt_end_transmit() before sleeping
 994          * in order to allow access to the socket to other RPC requests.
 995          */
 996         call_transmit_status(task);
 997         if (task->tk_msg.rpc_proc->p_decode != NULL)
 998                 return;
 999         task->tk_action = rpc_exit_task;
1000         rpc_wake_up_task(task);
1001 }
1002
1003 /*
1004  * 5a.  Handle cleanup after a transmission
1005  */
1006 static void
1007 call_transmit_status(struct rpc_task *task)
1008 {
1009         task->tk_action = call_status;
1010         /*
1011          * Special case: if we've been waiting on the socket's write_space()
1012          * callback, then don't call xprt_end_transmit().
1013          */
1014         if (task->tk_status == -EAGAIN)
1015                 return;
1016         xprt_end_transmit(task);
1017         rpc_task_force_reencode(task);
1018 }
1019
1020 /*
1021  * 6.   Sort out the RPC call status
1022  */
1023 static void
1024 call_status(struct rpc_task *task)
1025 {
1026         struct rpc_clnt *clnt = task->tk_client;
1027         struct rpc_rqst *req = task->tk_rqstp;
1028         int             status;
1029
1030         if (req->rq_received > 0 && !req->rq_bytes_sent)
1031                 task->tk_status = req->rq_received;
1032
1033         dprintk("RPC: %4d call_status (status %d)\n",
1034                                 task->tk_pid, task->tk_status);
1035
1036         status = task->tk_status;
1037         if (status >= 0) {
1038                 task->tk_action = call_decode;
1039                 return;
1040         }
1041
1042         task->tk_status = 0;
1043         switch(status) {
1044         case -EHOSTDOWN:
1045         case -EHOSTUNREACH:
1046         case -ENETUNREACH:
1047                 /*
1048                  * Delay any retries for 3 seconds, then handle as if it
1049                  * were a timeout.
1050                  */
1051                 rpc_delay(task, 3*HZ);
1052         case -ETIMEDOUT:
1053                 task->tk_action = call_timeout;
1054                 break;
1055         case -ECONNREFUSED:
1056         case -ENOTCONN:
1057                 rpc_force_rebind(clnt);
1058                 task->tk_action = call_bind;
1059                 break;
1060         case -EAGAIN:
1061                 task->tk_action = call_transmit;
1062                 break;
1063         case -EIO:
1064                 /* shutdown or soft timeout */
1065                 rpc_exit(task, status);
1066                 break;
1067         default:
1068                 printk("%s: RPC call returned error %d\n",
1069                                clnt->cl_protname, -status);
1070                 rpc_exit(task, status);
1071         }
1072 }
1073
1074 /*
1075  * 6a.  Handle RPC timeout
1076  *      We do not release the request slot, so we keep using the
1077  *      same XID for all retransmits.
1078  */
1079 static void
1080 call_timeout(struct rpc_task *task)
1081 {
1082         struct rpc_clnt *clnt = task->tk_client;
1083
1084         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1085                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1086                 goto retry;
1087         }
1088
1089         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1090         task->tk_timeouts++;
1091
1092         if (RPC_IS_SOFT(task)) {
1093                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1094                                 clnt->cl_protname, clnt->cl_server);
1095                 rpc_exit(task, -EIO);
1096                 return;
1097         }
1098
1099         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1100                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1101                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1102                         clnt->cl_protname, clnt->cl_server);
1103         }
1104         rpc_force_rebind(clnt);
1105
1106 retry:
1107         clnt->cl_stats->rpcretrans++;
1108         task->tk_action = call_bind;
1109         task->tk_status = 0;
1110 }
1111
1112 /*
1113  * 7.   Decode the RPC reply
1114  */
1115 static void
1116 call_decode(struct rpc_task *task)
1117 {
1118         struct rpc_clnt *clnt = task->tk_client;
1119         struct rpc_rqst *req = task->tk_rqstp;
1120         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1121         __be32          *p;
1122
1123         dprintk("RPC: %4d call_decode (status %d)\n",
1124                                 task->tk_pid, task->tk_status);
1125
1126         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1127                 printk(KERN_NOTICE "%s: server %s OK\n",
1128                         clnt->cl_protname, clnt->cl_server);
1129                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1130         }
1131
1132         if (task->tk_status < 12) {
1133                 if (!RPC_IS_SOFT(task)) {
1134                         task->tk_action = call_bind;
1135                         clnt->cl_stats->rpcretrans++;
1136                         goto out_retry;
1137                 }
1138                 dprintk("%s: too small RPC reply size (%d bytes)\n",
1139                         clnt->cl_protname, task->tk_status);
1140                 task->tk_action = call_timeout;
1141                 goto out_retry;
1142         }
1143
1144         /*
1145          * Ensure that we see all writes made by xprt_complete_rqst()
1146          * before it changed req->rq_received.
1147          */
1148         smp_rmb();
1149         req->rq_rcv_buf.len = req->rq_private_buf.len;
1150
1151         /* Check that the softirq receive buffer is valid */
1152         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1153                                 sizeof(req->rq_rcv_buf)) != 0);
1154
1155         /* Verify the RPC header */
1156         p = call_verify(task);
1157         if (IS_ERR(p)) {
1158                 if (p == ERR_PTR(-EAGAIN))
1159                         goto out_retry;
1160                 return;
1161         }
1162
1163         task->tk_action = rpc_exit_task;
1164
1165         if (decode) {
1166                 lock_kernel();
1167                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1168                                                       task->tk_msg.rpc_resp);
1169                 unlock_kernel();
1170         }
1171         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1172                                         task->tk_status);
1173         return;
1174 out_retry:
1175         req->rq_received = req->rq_private_buf.len = 0;
1176         task->tk_status = 0;
1177 }
1178
1179 /*
1180  * 8.   Refresh the credentials if rejected by the server
1181  */
1182 static void
1183 call_refresh(struct rpc_task *task)
1184 {
1185         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1186
1187         xprt_release(task);     /* Must do to obtain new XID */
1188         task->tk_action = call_refreshresult;
1189         task->tk_status = 0;
1190         task->tk_client->cl_stats->rpcauthrefresh++;
1191         rpcauth_refreshcred(task);
1192 }
1193
1194 /*
1195  * 8a.  Process the results of a credential refresh
1196  */
1197 static void
1198 call_refreshresult(struct rpc_task *task)
1199 {
1200         int status = task->tk_status;
1201         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1202                                 task->tk_pid, task->tk_status);
1203
1204         task->tk_status = 0;
1205         task->tk_action = call_reserve;
1206         if (status >= 0 && rpcauth_uptodatecred(task))
1207                 return;
1208         if (status == -EACCES) {
1209                 rpc_exit(task, -EACCES);
1210                 return;
1211         }
1212         task->tk_action = call_refresh;
1213         if (status != -ETIMEDOUT)
1214                 rpc_delay(task, 3*HZ);
1215         return;
1216 }
1217
1218 /*
1219  * Call header serialization
1220  */
1221 static __be32 *
1222 call_header(struct rpc_task *task)
1223 {
1224         struct rpc_clnt *clnt = task->tk_client;
1225         struct rpc_rqst *req = task->tk_rqstp;
1226         __be32          *p = req->rq_svec[0].iov_base;
1227
1228         /* FIXME: check buffer size? */
1229
1230         p = xprt_skip_transport_header(task->tk_xprt, p);
1231         *p++ = req->rq_xid;             /* XID */
1232         *p++ = htonl(RPC_CALL);         /* CALL */
1233         *p++ = htonl(RPC_VERSION);      /* RPC version */
1234         *p++ = htonl(clnt->cl_prog);    /* program number */
1235         *p++ = htonl(clnt->cl_vers);    /* program version */
1236         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1237         p = rpcauth_marshcred(task, p);
1238         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1239         return p;
1240 }
1241
1242 /*
1243  * Reply header verification
1244  */
1245 static __be32 *
1246 call_verify(struct rpc_task *task)
1247 {
1248         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1249         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1250         __be32  *p = iov->iov_base;
1251         u32 n;
1252         int error = -EACCES;
1253
1254         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1255                 /* RFC-1014 says that the representation of XDR data must be a
1256                  * multiple of four bytes
1257                  * - if it isn't pointer subtraction in the NFS client may give
1258                  *   undefined results
1259                  */
1260                 printk(KERN_WARNING
1261                        "call_verify: XDR representation not a multiple of"
1262                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1263                 goto out_eio;
1264         }
1265         if ((len -= 3) < 0)
1266                 goto out_overflow;
1267         p += 1; /* skip XID */
1268
1269         if ((n = ntohl(*p++)) != RPC_REPLY) {
1270                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1271                 goto out_garbage;
1272         }
1273         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1274                 if (--len < 0)
1275                         goto out_overflow;
1276                 switch ((n = ntohl(*p++))) {
1277                         case RPC_AUTH_ERROR:
1278                                 break;
1279                         case RPC_MISMATCH:
1280                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1281                                 error = -EPROTONOSUPPORT;
1282                                 goto out_err;
1283                         default:
1284                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1285                                 goto out_eio;
1286                 }
1287                 if (--len < 0)
1288                         goto out_overflow;
1289                 switch ((n = ntohl(*p++))) {
1290                 case RPC_AUTH_REJECTEDCRED:
1291                 case RPC_AUTH_REJECTEDVERF:
1292                 case RPCSEC_GSS_CREDPROBLEM:
1293                 case RPCSEC_GSS_CTXPROBLEM:
1294                         if (!task->tk_cred_retry)
1295                                 break;
1296                         task->tk_cred_retry--;
1297                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1298                                                         task->tk_pid);
1299                         rpcauth_invalcred(task);
1300                         task->tk_action = call_refresh;
1301                         goto out_retry;
1302                 case RPC_AUTH_BADCRED:
1303                 case RPC_AUTH_BADVERF:
1304                         /* possibly garbled cred/verf? */
1305                         if (!task->tk_garb_retry)
1306                                 break;
1307                         task->tk_garb_retry--;
1308                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1309                                                         task->tk_pid);
1310                         task->tk_action = call_bind;
1311                         goto out_retry;
1312                 case RPC_AUTH_TOOWEAK:
1313                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1314                                "authentication.\n", task->tk_client->cl_server);
1315                         break;
1316                 default:
1317                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1318                         error = -EIO;
1319                 }
1320                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1321                                                 task->tk_pid, n);
1322                 goto out_err;
1323         }
1324         if (!(p = rpcauth_checkverf(task, p))) {
1325                 printk(KERN_WARNING "call_verify: auth check failed\n");
1326                 goto out_garbage;               /* bad verifier, retry */
1327         }
1328         len = p - (__be32 *)iov->iov_base - 1;
1329         if (len < 0)
1330                 goto out_overflow;
1331         switch ((n = ntohl(*p++))) {
1332         case RPC_SUCCESS:
1333                 return p;
1334         case RPC_PROG_UNAVAIL:
1335                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1336                                 (unsigned int)task->tk_client->cl_prog,
1337                                 task->tk_client->cl_server);
1338                 error = -EPFNOSUPPORT;
1339                 goto out_err;
1340         case RPC_PROG_MISMATCH:
1341                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1342                                 (unsigned int)task->tk_client->cl_prog,
1343                                 (unsigned int)task->tk_client->cl_vers,
1344                                 task->tk_client->cl_server);
1345                 error = -EPROTONOSUPPORT;
1346                 goto out_err;
1347         case RPC_PROC_UNAVAIL:
1348                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1349                                 task->tk_msg.rpc_proc,
1350                                 task->tk_client->cl_prog,
1351                                 task->tk_client->cl_vers,
1352                                 task->tk_client->cl_server);
1353                 error = -EOPNOTSUPP;
1354                 goto out_err;
1355         case RPC_GARBAGE_ARGS:
1356                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1357                 break;                  /* retry */
1358         default:
1359                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1360                 /* Also retry */
1361         }
1362
1363 out_garbage:
1364         task->tk_client->cl_stats->rpcgarbage++;
1365         if (task->tk_garb_retry) {
1366                 task->tk_garb_retry--;
1367                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1368                 task->tk_action = call_bind;
1369 out_retry:
1370                 return ERR_PTR(-EAGAIN);
1371         }
1372         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1373 out_eio:
1374         error = -EIO;
1375 out_err:
1376         rpc_exit(task, error);
1377         return ERR_PTR(error);
1378 out_overflow:
1379         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1380         goto out_garbage;
1381 }
1382
1383 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1384 {
1385         return 0;
1386 }
1387
1388 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1389 {
1390         return 0;
1391 }
1392
1393 static struct rpc_procinfo rpcproc_null = {
1394         .p_encode = rpcproc_encode_null,
1395         .p_decode = rpcproc_decode_null,
1396 };
1397
1398 int rpc_ping(struct rpc_clnt *clnt, int flags)
1399 {
1400         struct rpc_message msg = {
1401                 .rpc_proc = &rpcproc_null,
1402         };
1403         int err;
1404         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1405         err = rpc_call_sync(clnt, &msg, flags);
1406         put_rpccred(msg.rpc_cred);
1407         return err;
1408 }