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 <[email protected]>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <[email protected]>
  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 #ifdef RPC_DEBUG
  40 # define RPCDBG_FACILITY        RPCDBG_CALL
  41 #endif
  42
  43 #define dprint_status(t)                                        \
  44         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  45                         __FUNCTION__, t->tk_status)
  46
  47 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  48
  49
  50 static void     call_start(struct rpc_task *task);
  51 static void     call_reserve(struct rpc_task *task);
  52 static void     call_reserveresult(struct rpc_task *task);
  53 static void     call_allocate(struct rpc_task *task);
  54 static void     call_encode(struct rpc_task *task);
  55 static void     call_decode(struct rpc_task *task);
  56 static void     call_bind(struct rpc_task *task);
  57 static void     call_bind_status(struct rpc_task *task);
  58 static void     call_transmit(struct rpc_task *task);
  59 static void     call_status(struct rpc_task *task);
  60 static void     call_transmit_status(struct rpc_task *task);
  61 static void     call_refresh(struct rpc_task *task);
  62 static void     call_refreshresult(struct rpc_task *task);
  63 static void     call_timeout(struct rpc_task *task);
  64 static void     call_connect(struct rpc_task *task);
  65 static void     call_connect_status(struct rpc_task *task);
  66 static __be32 * call_header(struct rpc_task *task);
  67 static __be32 * call_verify(struct rpc_task *task);
  68
  69
  70 static int
  71 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  72 {
  73         static uint32_t clntid;
  74         int error;
  75
  76         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  77         clnt->cl_dentry = ERR_PTR(-ENOENT);
  78         if (dir_name == NULL)
  79                 return 0;
  80
  81         clnt->cl_vfsmnt = rpc_get_mount();
  82         if (IS_ERR(clnt->cl_vfsmnt))
  83                 return PTR_ERR(clnt->cl_vfsmnt);
  84
  85         for (;;) {
  86                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  87                                 "%s/clnt%x", dir_name,
  88                                 (unsigned int)clntid++);
  89                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  90                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  91                 if (!IS_ERR(clnt->cl_dentry))
  92                         return 0;
  93                 error = PTR_ERR(clnt->cl_dentry);
  94                 if (error != -EEXIST) {
  95                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  96                                         clnt->cl_pathname, error);
  97                         rpc_put_mount();
  98                         return error;
  99                 }
 100         }
 101 }
 102
 103 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 104 {
 105         struct rpc_version      *version;
 106         struct rpc_clnt         *clnt = NULL;
 107         struct rpc_auth         *auth;
 108         int err;
 109         int len;
 110
 111         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 112                         program->name, servname, xprt);
 113
 114         err = -EINVAL;
 115         if (!xprt)
 116                 goto out_no_xprt;
 117         if (vers >= program->nrvers || !(version = program->version[vers]))
 118                 goto out_err;
 119
 120         err = -ENOMEM;
 121         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 122         if (!clnt)
 123                 goto out_err;
 124         atomic_set(&clnt->cl_count, 1);
 125         clnt->cl_parent = clnt;
 126
 127         clnt->cl_server = clnt->cl_inline_name;
 128         len = strlen(servname) + 1;
 129         if (len > sizeof(clnt->cl_inline_name)) {
 130                 char *buf = kmalloc(len, GFP_KERNEL);
 131                 if (buf != 0)
 132                         clnt->cl_server = buf;
 133                 else
 134                         len = sizeof(clnt->cl_inline_name);
 135         }
 136         strlcpy(clnt->cl_server, servname, len);
 137
 138         clnt->cl_xprt     = xprt;
 139         clnt->cl_procinfo = version->procs;
 140         clnt->cl_maxproc  = version->nrprocs;
 141         clnt->cl_protname = program->name;
 142         clnt->cl_prog     = program->number;
 143         clnt->cl_vers     = version->number;
 144         clnt->cl_stats    = program->stats;
 145         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 146         err = -ENOMEM;
 147         if (clnt->cl_metrics == NULL)
 148                 goto out_no_stats;
 149         clnt->cl_program  = program;
 150         INIT_LIST_HEAD(&clnt->cl_tasks);
 151         spin_lock_init(&clnt->cl_lock);
 152
 153         if (!xprt_bound(clnt->cl_xprt))
 154                 clnt->cl_autobind = 1;
 155
 156         clnt->cl_rtt = &clnt->cl_rtt_default;
 157         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 158
 159         kref_init(&clnt->cl_kref);
 160
 161         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 162         if (err < 0)
 163                 goto out_no_path;
 164
 165         auth = rpcauth_create(flavor, clnt);
 166         if (IS_ERR(auth)) {
 167                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 168                                 flavor);
 169                 err = PTR_ERR(auth);
 170                 goto out_no_auth;
 171         }
 172
 173         /* save the nodename */
 174         clnt->cl_nodelen = strlen(utsname()->nodename);
 175         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 176                 clnt->cl_nodelen = UNX_MAXNODENAME;
 177         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 178         rpc_register_client(clnt);
 179         return clnt;
 180
 181 out_no_auth:
 182         if (!IS_ERR(clnt->cl_dentry)) {
 183                 rpc_rmdir(clnt->cl_dentry);
 184                 rpc_put_mount();
 185         }
 186 out_no_path:
 187         rpc_free_iostats(clnt->cl_metrics);
 188 out_no_stats:
 189         if (clnt->cl_server != clnt->cl_inline_name)
 190                 kfree(clnt->cl_server);
 191         kfree(clnt);
 192 out_err:
 193         xprt_put(xprt);
 194 out_no_xprt:
 195         return ERR_PTR(err);
 196 }
 197
 198 /*
 199  * rpc_create - create an RPC client and transport with one call
 200  * @args: rpc_clnt create argument structure
 201  *
 202  * Creates and initializes an RPC transport and an RPC client.
 203  *
 204  * It can ping the server in order to determine if it is up, and to see if
 205  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 206  * this behavior so asynchronous tasks can also use rpc_create.
 207  */
 208 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 209 {
 210         struct rpc_xprt *xprt;
 211         struct rpc_clnt *clnt;
 212
 213         xprt = xprt_create_transport(args->protocol, args->address,
 214                                         args->addrsize, args->timeout);
 215         if (IS_ERR(xprt))
 216                 return (struct rpc_clnt *)xprt;
 217
 218         /*
 219          * By default, kernel RPC client connects from a reserved port.
 220          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 221          * but it is always enabled for rpciod, which handles the connect
 222          * operation.
 223          */
 224         xprt->resvport = 1;
 225         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 226                 xprt->resvport = 0;
 227
 228         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 229                         args->program->name, args->servername, xprt);
 230
 231         clnt = rpc_new_client(xprt, args->servername, args->program,
 232                                 args->version, args->authflavor);
 233         if (IS_ERR(clnt))
 234                 return clnt;
 235
 236         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 237                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 238                 if (err != 0) {
 239                         rpc_shutdown_client(clnt);
 240                         return ERR_PTR(err);
 241                 }
 242         }
 243
 244         clnt->cl_softrtry = 1;
 245         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 246                 clnt->cl_softrtry = 0;
 247
 248         if (args->flags & RPC_CLNT_CREATE_INTR)
 249                 clnt->cl_intr = 1;
 250         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 251                 clnt->cl_autobind = 1;
 252         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 253                 clnt->cl_oneshot = 1;
 254         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 255                 clnt->cl_discrtry = 1;
 256
 257         return clnt;
 258 }
 259 EXPORT_SYMBOL_GPL(rpc_create);
 260
 261 /*
 262  * This function clones the RPC client structure. It allows us to share the
 263  * same transport while varying parameters such as the authentication
 264  * flavour.
 265  */
 266 struct rpc_clnt *
 267 rpc_clone_client(struct rpc_clnt *clnt)
 268 {
 269         struct rpc_clnt *new;
 270         int err = -ENOMEM;
 271
 272         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 273         if (!new)
 274                 goto out_no_clnt;
 275         atomic_set(&new->cl_count, 1);
 276         new->cl_metrics = rpc_alloc_iostats(clnt);
 277         if (new->cl_metrics == NULL)
 278                 goto out_no_stats;
 279         kref_init(&new->cl_kref);
 280         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 281         if (err != 0)
 282                 goto out_no_path;
 283         new->cl_parent = clnt;
 284         atomic_inc(&clnt->cl_count);
 285         new->cl_xprt = xprt_get(clnt->cl_xprt);
 286         /* Turn off autobind on clones */
 287         new->cl_autobind = 0;
 288         new->cl_oneshot = 0;
 289         new->cl_dead = 0;
 290         INIT_LIST_HEAD(&new->cl_tasks);
 291         spin_lock_init(&new->cl_lock);
 292         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 293         if (new->cl_auth)
 294                 atomic_inc(&new->cl_auth->au_count);
 295         rpc_register_client(new);
 296         return new;
 297 out_no_path:
 298         rpc_free_iostats(new->cl_metrics);
 299 out_no_stats:
 300         kfree(new);
 301 out_no_clnt:
 302         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
 303         return ERR_PTR(err);
 304 }
 305
 306 /*
 307  * Properly shut down an RPC client, terminating all outstanding
 308  * requests. Note that we must be certain that cl_oneshot and
 309  * cl_dead are cleared, or else the client would be destroyed
 310  * when the last task releases it.
 311  */
 312 int
 313 rpc_shutdown_client(struct rpc_clnt *clnt)
 314 {
 315         dprintk("RPC:       shutting down %s client for %s\n",
 316                         clnt->cl_protname, clnt->cl_server);
 317
 318         while (!list_empty(&clnt->cl_tasks)) {
 319                 /* Don't let rpc_release_client destroy us */
 320                 clnt->cl_oneshot = 0;
 321                 clnt->cl_dead = 0;
 322                 rpc_killall_tasks(clnt);
 323                 wait_event_timeout(destroy_wait,
 324                         list_empty(&clnt->cl_tasks), 1*HZ);
 325         }
 326
 327         return rpc_destroy_client(clnt);
 328 }
 329
 330 /*
 331  * Free an RPC client
 332  */
 333 static void
 334 rpc_free_client(struct kref *kref)
 335 {
 336         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 337
 338         dprintk("RPC:       destroying %s client for %s\n",
 339                         clnt->cl_protname, clnt->cl_server);
 340         if (clnt->cl_auth) {
 341                 rpcauth_destroy(clnt->cl_auth);
 342                 clnt->cl_auth = NULL;
 343         }
 344         if (!IS_ERR(clnt->cl_dentry)) {
 345                 rpc_rmdir(clnt->cl_dentry);
 346                 rpc_put_mount();
 347         }
 348         if (clnt->cl_parent != clnt) {
 349                 rpc_destroy_client(clnt->cl_parent);
 350                 goto out_free;
 351         }
 352         if (clnt->cl_server != clnt->cl_inline_name)
 353                 kfree(clnt->cl_server);
 354 out_free:
 355         rpc_unregister_client(clnt);
 356         rpc_free_iostats(clnt->cl_metrics);
 357         clnt->cl_metrics = NULL;
 358         xprt_put(clnt->cl_xprt);
 359         kfree(clnt);
 360 }
 361
 362 /*
 363  * Release reference to the RPC client
 364  */
 365 void
 366 rpc_release_client(struct rpc_clnt *clnt)
 367 {
 368         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 369
 370         if (list_empty(&clnt->cl_tasks))
 371                 wake_up(&destroy_wait);
 372         if (clnt->cl_oneshot || clnt->cl_dead)
 373                 rpc_destroy_client(clnt);
 374         kref_put(&clnt->cl_kref, rpc_free_client);
 375 }
 376
 377 /*
 378  * Delete an RPC client
 379  */
 380 int
 381 rpc_destroy_client(struct rpc_clnt *clnt)
 382 {
 383         if (!atomic_dec_and_test(&clnt->cl_count))
 384                 return 1;
 385         kref_put(&clnt->cl_kref, rpc_free_client);
 386         return 0;
 387 }
 388
 389 /**
 390  * rpc_bind_new_program - bind a new RPC program to an existing client
 391  * @old - old rpc_client
 392  * @program - rpc program to set
 393  * @vers - rpc program version
 394  *
 395  * Clones the rpc client and sets up a new RPC program. This is mainly
 396  * of use for enabling different RPC programs to share the same transport.
 397  * The Sun NFSv2/v3 ACL protocol can do this.
 398  */
 399 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 400                                       struct rpc_program *program,
 401                                       int vers)
 402 {
 403         struct rpc_clnt *clnt;
 404         struct rpc_version *version;
 405         int err;
 406
 407         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 408         version = program->version[vers];
 409         clnt = rpc_clone_client(old);
 410         if (IS_ERR(clnt))
 411                 goto out;
 412         clnt->cl_procinfo = version->procs;
 413         clnt->cl_maxproc  = version->nrprocs;
 414         clnt->cl_protname = program->name;
 415         clnt->cl_prog     = program->number;
 416         clnt->cl_vers     = version->number;
 417         clnt->cl_stats    = program->stats;
 418         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 419         if (err != 0) {
 420                 rpc_shutdown_client(clnt);
 421                 clnt = ERR_PTR(err);
 422         }
 423 out:
 424         return clnt;
 425 }
 426
 427 /*
 428  * Default callback for async RPC calls
 429  */
 430 static void
 431 rpc_default_callback(struct rpc_task *task, void *data)
 432 {
 433 }
 434
 435 static const struct rpc_call_ops rpc_default_ops = {
 436         .rpc_call_done = rpc_default_callback,
 437 };
 438
 439 /*
 440  *      Export the signal mask handling for synchronous code that
 441  *      sleeps on RPC calls
 442  */
 443 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 444
 445 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 446 {
 447         unsigned long   sigallow = sigmask(SIGKILL);
 448         sigset_t sigmask;
 449
 450         /* Block all signals except those listed in sigallow */
 451         if (intr)
 452                 sigallow |= RPC_INTR_SIGNALS;
 453         siginitsetinv(&sigmask, sigallow);
 454         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 455 }
 456
 457 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 458 {
 459         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 460 }
 461
 462 static inline void rpc_restore_sigmask(sigset_t *oldset)
 463 {
 464         sigprocmask(SIG_SETMASK, oldset, NULL);
 465 }
 466
 467 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 468 {
 469         rpc_save_sigmask(oldset, clnt->cl_intr);
 470 }
 471
 472 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 473 {
 474         rpc_restore_sigmask(oldset);
 475 }
 476
 477 /*
 478  * New rpc_call implementation
 479  */
 480 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 481 {
 482         struct rpc_task *task;
 483         sigset_t        oldset;
 484         int             status;
 485
 486         /* If this client is slain all further I/O fails */
 487         if (clnt->cl_dead)
 488                 return -EIO;
 489
 490         BUG_ON(flags & RPC_TASK_ASYNC);
 491
 492         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 493         if (task == NULL)
 494                 return -ENOMEM;
 495
 496         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 497         rpc_task_sigmask(task, &oldset);
 498
 499         /* Set up the call info struct and execute the task */
 500         rpc_call_setup(task, msg, 0);
 501         if (task->tk_status == 0) {
 502                 atomic_inc(&task->tk_count);
 503                 rpc_execute(task);
 504         }
 505         status = task->tk_status;
 506         rpc_put_task(task);
 507         rpc_restore_sigmask(&oldset);
 508         return status;
 509 }
 510
 511 /*
 512  * New rpc_call implementation
 513  */
 514 int
 515 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 516                const struct rpc_call_ops *tk_ops, void *data)
 517 {
 518         struct rpc_task *task;
 519         sigset_t        oldset;
 520         int             status;
 521
 522         /* If this client is slain all further I/O fails */
 523         status = -EIO;
 524         if (clnt->cl_dead)
 525                 goto out_release;
 526
 527         flags |= RPC_TASK_ASYNC;
 528
 529         /* Create/initialize a new RPC task */
 530         status = -ENOMEM;
 531         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 532                 goto out_release;
 533
 534         /* Mask signals on GSS_AUTH upcalls */
 535         rpc_task_sigmask(task, &oldset);
 536
 537         rpc_call_setup(task, msg, 0);
 538
 539         /* Set up the call info struct and execute the task */
 540         status = task->tk_status;
 541         if (status == 0)
 542                 rpc_execute(task);
 543         else
 544                 rpc_put_task(task);
 545
 546         rpc_restore_sigmask(&oldset);
 547         return status;
 548 out_release:
 549         rpc_release_calldata(tk_ops, data);
 550         return status;
 551 }
 552
 553
 554 void
 555 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 556 {
 557         task->tk_msg   = *msg;
 558         task->tk_flags |= flags;
 559         /* Bind the user cred */
 560         if (task->tk_msg.rpc_cred != NULL)
 561                 rpcauth_holdcred(task);
 562         else
 563                 rpcauth_bindcred(task);
 564
 565         if (task->tk_status == 0)
 566                 task->tk_action = call_start;
 567         else
 568                 task->tk_action = rpc_exit_task;
 569 }
 570
 571 /**
 572  * rpc_peeraddr - extract remote peer address from clnt's xprt
 573  * @clnt: RPC client structure
 574  * @buf: target buffer
 575  * @size: length of target buffer
 576  *
 577  * Returns the number of bytes that are actually in the stored address.
 578  */
 579 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 580 {
 581         size_t bytes;
 582         struct rpc_xprt *xprt = clnt->cl_xprt;
 583
 584         bytes = sizeof(xprt->addr);
 585         if (bytes > bufsize)
 586                 bytes = bufsize;
 587         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 588         return xprt->addrlen;
 589 }
 590 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 591
 592 /**
 593  * rpc_peeraddr2str - return remote peer address in printable format
 594  * @clnt: RPC client structure
 595  * @format: address format
 596  *
 597  */
 598 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 599 {
 600         struct rpc_xprt *xprt = clnt->cl_xprt;
 601
 602         if (xprt->address_strings[format] != NULL)
 603                 return xprt->address_strings[format];
 604         else
 605                 return "unprintable";
 606 }
 607 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 608
 609 void
 610 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 611 {
 612         struct rpc_xprt *xprt = clnt->cl_xprt;
 613         if (xprt->ops->set_buffer_size)
 614                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 615 }
 616
 617 /*
 618  * Return size of largest payload RPC client can support, in bytes
 619  *
 620  * For stream transports, this is one RPC record fragment (see RFC
 621  * 1831), as we don't support multi-record requests yet.  For datagram
 622  * transports, this is the size of an IP packet minus the IP, UDP, and
 623  * RPC header sizes.
 624  */
 625 size_t rpc_max_payload(struct rpc_clnt *clnt)
 626 {
 627         return clnt->cl_xprt->max_payload;
 628 }
 629 EXPORT_SYMBOL_GPL(rpc_max_payload);
 630
 631 /**
 632  * rpc_force_rebind - force transport to check that remote port is unchanged
 633  * @clnt: client to rebind
 634  *
 635  */
 636 void rpc_force_rebind(struct rpc_clnt *clnt)
 637 {
 638         if (clnt->cl_autobind)
 639                 xprt_clear_bound(clnt->cl_xprt);
 640 }
 641 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 642
 643 /*
 644  * Restart an (async) RPC call. Usually called from within the
 645  * exit handler.
 646  */
 647 void
 648 rpc_restart_call(struct rpc_task *task)
 649 {
 650         if (RPC_ASSASSINATED(task))
 651                 return;
 652
 653         task->tk_action = call_start;
 654 }
 655
 656 /*
 657  * 0.  Initial state
 658  *
 659  *     Other FSM states can be visited zero or more times, but
 660  *     this state is visited exactly once for each RPC.
 661  */
 662 static void
 663 call_start(struct rpc_task *task)
 664 {
 665         struct rpc_clnt *clnt = task->tk_client;
 666
 667         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
 668                         clnt->cl_protname, clnt->cl_vers,
 669                         task->tk_msg.rpc_proc->p_proc,
 670                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 671
 672         /* Increment call count */
 673         task->tk_msg.rpc_proc->p_count++;
 674         clnt->cl_stats->rpccnt++;
 675         task->tk_action = call_reserve;
 676 }
 677
 678 /*
 679  * 1.   Reserve an RPC call slot
 680  */
 681 static void
 682 call_reserve(struct rpc_task *task)
 683 {
 684         dprint_status(task);
 685
 686         if (!rpcauth_uptodatecred(task)) {
 687                 task->tk_action = call_refresh;
 688                 return;
 689         }
 690
 691         task->tk_status  = 0;
 692         task->tk_action  = call_reserveresult;
 693         xprt_reserve(task);
 694 }
 695
 696 /*
 697  * 1b.  Grok the result of xprt_reserve()
 698  */
 699 static void
 700 call_reserveresult(struct rpc_task *task)
 701 {
 702         int status = task->tk_status;
 703
 704         dprint_status(task);
 705
 706         /*
 707          * After a call to xprt_reserve(), we must have either
 708          * a request slot or else an error status.
 709          */
 710         task->tk_status = 0;
 711         if (status >= 0) {
 712                 if (task->tk_rqstp) {
 713                         task->tk_action = call_allocate;
 714                         return;
 715                 }
 716
 717                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 718                                 __FUNCTION__, status);
 719                 rpc_exit(task, -EIO);
 720                 return;
 721         }
 722
 723         /*
 724          * Even though there was an error, we may have acquired
 725          * a request slot somehow.  Make sure not to leak it.
 726          */
 727         if (task->tk_rqstp) {
 728                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 729                                 __FUNCTION__, status);
 730                 xprt_release(task);
 731         }
 732
 733         switch (status) {
 734         case -EAGAIN:   /* woken up; retry */
 735                 task->tk_action = call_reserve;
 736                 return;
 737         case -EIO:      /* probably a shutdown */
 738                 break;
 739         default:
 740                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 741                                 __FUNCTION__, status);
 742                 break;
 743         }
 744         rpc_exit(task, status);
 745 }
 746
 747 /*
 748  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 749  *      (Note: buffer memory is freed in xprt_release).
 750  */
 751 static void
 752 call_allocate(struct rpc_task *task)
 753 {
 754         unsigned int slack = task->tk_auth->au_cslack;
 755         struct rpc_rqst *req = task->tk_rqstp;
 756         struct rpc_xprt *xprt = task->tk_xprt;
 757         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 758
 759         dprint_status(task);
 760
 761         task->tk_status = 0;
 762         task->tk_action = call_bind;
 763
 764         if (req->rq_buffer)
 765                 return;
 766
 767         if (proc->p_proc != 0) {
 768                 BUG_ON(proc->p_arglen == 0);
 769                 if (proc->p_decode != NULL)
 770                         BUG_ON(proc->p_replen == 0);
 771         }
 772
 773         /*
 774          * Calculate the size (in quads) of the RPC call
 775          * and reply headers, and convert both values
 776          * to byte sizes.
 777          */
 778         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 779         req->rq_callsize <<= 2;
 780         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 781         req->rq_rcvsize <<= 2;
 782
 783         req->rq_buffer = xprt->ops->buf_alloc(task,
 784                                         req->rq_callsize + req->rq_rcvsize);
 785         if (req->rq_buffer != NULL)
 786                 return;
 787
 788         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 789
 790         if (RPC_IS_ASYNC(task) || !signalled()) {
 791                 xprt_release(task);
 792                 task->tk_action = call_reserve;
 793                 rpc_delay(task, HZ>>4);
 794                 return;
 795         }
 796
 797         rpc_exit(task, -ERESTARTSYS);
 798 }
 799
 800 static inline int
 801 rpc_task_need_encode(struct rpc_task *task)
 802 {
 803         return task->tk_rqstp->rq_snd_buf.len == 0;
 804 }
 805
 806 static inline void
 807 rpc_task_force_reencode(struct rpc_task *task)
 808 {
 809         task->tk_rqstp->rq_snd_buf.len = 0;
 810 }
 811
 812 static inline void
 813 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 814 {
 815         buf->head[0].iov_base = start;
 816         buf->head[0].iov_len = len;
 817         buf->tail[0].iov_len = 0;
 818         buf->page_len = 0;
 819         buf->len = 0;
 820         buf->buflen = len;
 821 }
 822
 823 /*
 824  * 3.   Encode arguments of an RPC call
 825  */
 826 static void
 827 call_encode(struct rpc_task *task)
 828 {
 829         struct rpc_rqst *req = task->tk_rqstp;
 830         kxdrproc_t      encode;
 831         __be32          *p;
 832
 833         dprint_status(task);
 834
 835         rpc_xdr_buf_init(&req->rq_snd_buf,
 836                          req->rq_buffer,
 837                          req->rq_callsize);
 838         rpc_xdr_buf_init(&req->rq_rcv_buf,
 839                          (char *)req->rq_buffer + req->rq_callsize,
 840                          req->rq_rcvsize);
 841
 842         /* Encode header and provided arguments */
 843         encode = task->tk_msg.rpc_proc->p_encode;
 844         if (!(p = call_header(task))) {
 845                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 846                 rpc_exit(task, -EIO);
 847                 return;
 848         }
 849         if (encode == NULL)
 850                 return;
 851
 852         lock_kernel();
 853         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 854                         task->tk_msg.rpc_argp);
 855         unlock_kernel();
 856         if (task->tk_status == -ENOMEM) {
 857                 /* XXX: Is this sane? */
 858                 rpc_delay(task, 3*HZ);
 859                 task->tk_status = -EAGAIN;
 860         }
 861 }
 862
 863 /*
 864  * 4.   Get the server port number if not yet set
 865  */
 866 static void
 867 call_bind(struct rpc_task *task)
 868 {
 869         struct rpc_xprt *xprt = task->tk_xprt;
 870
 871         dprint_status(task);
 872
 873         task->tk_action = call_connect;
 874         if (!xprt_bound(xprt)) {
 875                 task->tk_action = call_bind_status;
 876                 task->tk_timeout = xprt->bind_timeout;
 877                 xprt->ops->rpcbind(task);
 878         }
 879 }
 880
 881 /*
 882  * 4a.  Sort out bind result
 883  */
 884 static void
 885 call_bind_status(struct rpc_task *task)
 886 {
 887         int status = -EACCES;
 888
 889         if (task->tk_status >= 0) {
 890                 dprint_status(task);
 891                 task->tk_status = 0;
 892                 task->tk_action = call_connect;
 893                 return;
 894         }
 895
 896         switch (task->tk_status) {
 897         case -EACCES:
 898                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 899                                 "unavailable\n", task->tk_pid);
 900                 rpc_delay(task, 3*HZ);
 901                 goto retry_timeout;
 902         case -ETIMEDOUT:
 903                 dprintk("RPC: %5u rpcbind request timed out\n",
 904                                 task->tk_pid);
 905                 goto retry_timeout;
 906         case -EPFNOSUPPORT:
 907                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 908                                 task->tk_pid);
 909                 break;
 910         case -EPROTONOSUPPORT:
 911                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 912                                 task->tk_pid);
 913                 task->tk_status = 0;
 914                 task->tk_action = call_bind;
 915                 return;
 916         default:
 917                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 918                                 task->tk_pid, -task->tk_status);
 919                 status = -EIO;
 920         }
 921
 922         rpc_exit(task, status);
 923         return;
 924
 925 retry_timeout:
 926         task->tk_action = call_timeout;
 927 }
 928
 929 /*
 930  * 4b.  Connect to the RPC server
 931  */
 932 static void
 933 call_connect(struct rpc_task *task)
 934 {
 935         struct rpc_xprt *xprt = task->tk_xprt;
 936
 937         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 938                         task->tk_pid, xprt,
 939                         (xprt_connected(xprt) ? "is" : "is not"));
 940
 941         task->tk_action = call_transmit;
 942         if (!xprt_connected(xprt)) {
 943                 task->tk_action = call_connect_status;
 944                 if (task->tk_status < 0)
 945                         return;
 946                 xprt_connect(task);
 947         }
 948 }
 949
 950 /*
 951  * 4c.  Sort out connect result
 952  */
 953 static void
 954 call_connect_status(struct rpc_task *task)
 955 {
 956         struct rpc_clnt *clnt = task->tk_client;
 957         int status = task->tk_status;
 958
 959         dprint_status(task);
 960
 961         task->tk_status = 0;
 962         if (status >= 0) {
 963                 clnt->cl_stats->netreconn++;
 964                 task->tk_action = call_transmit;
 965                 return;
 966         }
 967
 968         /* Something failed: remote service port may have changed */
 969         rpc_force_rebind(clnt);
 970
 971         switch (status) {
 972         case -ENOTCONN:
 973         case -EAGAIN:
 974                 task->tk_action = call_bind;
 975                 if (!RPC_IS_SOFT(task))
 976                         return;
 977                 /* if soft mounted, test if we've timed out */
 978         case -ETIMEDOUT:
 979                 task->tk_action = call_timeout;
 980                 return;
 981         }
 982         rpc_exit(task, -EIO);
 983 }
 984
 985 /*
 986  * 5.   Transmit the RPC request, and wait for reply
 987  */
 988 static void
 989 call_transmit(struct rpc_task *task)
 990 {
 991         dprint_status(task);
 992
 993         task->tk_action = call_status;
 994         if (task->tk_status < 0)
 995                 return;
 996         task->tk_status = xprt_prepare_transmit(task);
 997         if (task->tk_status != 0)
 998                 return;
 999         task->tk_action = call_transmit_status;
1000         /* Encode here so that rpcsec_gss can use correct sequence number. */
1001         if (rpc_task_need_encode(task)) {
1002                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1003                 call_encode(task);
1004                 /* Did the encode result in an error condition? */
1005                 if (task->tk_status != 0)
1006                         return;
1007         }
1008         xprt_transmit(task);
1009         if (task->tk_status < 0)
1010                 return;
1011         /*
1012          * On success, ensure that we call xprt_end_transmit() before sleeping
1013          * in order to allow access to the socket to other RPC requests.
1014          */
1015         call_transmit_status(task);
1016         if (task->tk_msg.rpc_proc->p_decode != NULL)
1017                 return;
1018         task->tk_action = rpc_exit_task;
1019         rpc_wake_up_task(task);
1020 }
1021
1022 /*
1023  * 5a.  Handle cleanup after a transmission
1024  */
1025 static void
1026 call_transmit_status(struct rpc_task *task)
1027 {
1028         task->tk_action = call_status;
1029         /*
1030          * Special case: if we've been waiting on the socket's write_space()
1031          * callback, then don't call xprt_end_transmit().
1032          */
1033         if (task->tk_status == -EAGAIN)
1034                 return;
1035         xprt_end_transmit(task);
1036         rpc_task_force_reencode(task);
1037 }
1038
1039 /*
1040  * 6.   Sort out the RPC call status
1041  */
1042 static void
1043 call_status(struct rpc_task *task)
1044 {
1045         struct rpc_clnt *clnt = task->tk_client;
1046         struct rpc_rqst *req = task->tk_rqstp;
1047         int             status;
1048
1049         if (req->rq_received > 0 && !req->rq_bytes_sent)
1050                 task->tk_status = req->rq_received;
1051
1052         dprint_status(task);
1053
1054         status = task->tk_status;
1055         if (status >= 0) {
1056                 task->tk_action = call_decode;
1057                 return;
1058         }
1059
1060         task->tk_status = 0;
1061         switch(status) {
1062         case -EHOSTDOWN:
1063         case -EHOSTUNREACH:
1064         case -ENETUNREACH:
1065                 /*
1066                  * Delay any retries for 3 seconds, then handle as if it
1067                  * were a timeout.
1068                  */
1069                 rpc_delay(task, 3*HZ);
1070         case -ETIMEDOUT:
1071                 task->tk_action = call_timeout;
1072                 if (task->tk_client->cl_discrtry)
1073                         xprt_disconnect(task->tk_xprt);
1074                 break;
1075         case -ECONNREFUSED:
1076         case -ENOTCONN:
1077                 rpc_force_rebind(clnt);
1078                 task->tk_action = call_bind;
1079                 break;
1080         case -EAGAIN:
1081                 task->tk_action = call_transmit;
1082                 break;
1083         case -EIO:
1084                 /* shutdown or soft timeout */
1085                 rpc_exit(task, status);
1086                 break;
1087         default:
1088                 printk("%s: RPC call returned error %d\n",
1089                                clnt->cl_protname, -status);
1090                 rpc_exit(task, status);
1091         }
1092 }
1093
1094 /*
1095  * 6a.  Handle RPC timeout
1096  *      We do not release the request slot, so we keep using the
1097  *      same XID for all retransmits.
1098  */
1099 static void
1100 call_timeout(struct rpc_task *task)
1101 {
1102         struct rpc_clnt *clnt = task->tk_client;
1103
1104         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1105                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1106                 goto retry;
1107         }
1108
1109         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1110         task->tk_timeouts++;
1111
1112         if (RPC_IS_SOFT(task)) {
1113                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1114                                 clnt->cl_protname, clnt->cl_server);
1115                 rpc_exit(task, -EIO);
1116                 return;
1117         }
1118
1119         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1120                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1121                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1122                         clnt->cl_protname, clnt->cl_server);
1123         }
1124         rpc_force_rebind(clnt);
1125
1126 retry:
1127         clnt->cl_stats->rpcretrans++;
1128         task->tk_action = call_bind;
1129         task->tk_status = 0;
1130 }
1131
1132 /*
1133  * 7.   Decode the RPC reply
1134  */
1135 static void
1136 call_decode(struct rpc_task *task)
1137 {
1138         struct rpc_clnt *clnt = task->tk_client;
1139         struct rpc_rqst *req = task->tk_rqstp;
1140         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1141         __be32          *p;
1142
1143         dprintk("RPC: %5u call_decode (status %d)\n",
1144                         task->tk_pid, task->tk_status);
1145
1146         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1147                 printk(KERN_NOTICE "%s: server %s OK\n",
1148                         clnt->cl_protname, clnt->cl_server);
1149                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1150         }
1151
1152         if (task->tk_status < 12) {
1153                 if (!RPC_IS_SOFT(task)) {
1154                         task->tk_action = call_bind;
1155                         clnt->cl_stats->rpcretrans++;
1156                         goto out_retry;
1157                 }
1158                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1159                                 clnt->cl_protname, task->tk_status);
1160                 task->tk_action = call_timeout;
1161                 goto out_retry;
1162         }
1163
1164         /*
1165          * Ensure that we see all writes made by xprt_complete_rqst()
1166          * before it changed req->rq_received.
1167          */
1168         smp_rmb();
1169         req->rq_rcv_buf.len = req->rq_private_buf.len;
1170
1171         /* Check that the softirq receive buffer is valid */
1172         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1173                                 sizeof(req->rq_rcv_buf)) != 0);
1174
1175         /* Verify the RPC header */
1176         p = call_verify(task);
1177         if (IS_ERR(p)) {
1178                 if (p == ERR_PTR(-EAGAIN))
1179                         goto out_retry;
1180                 return;
1181         }
1182
1183         task->tk_action = rpc_exit_task;
1184
1185         if (decode) {
1186                 lock_kernel();
1187                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1188                                                       task->tk_msg.rpc_resp);
1189                 unlock_kernel();
1190         }
1191         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1192                         task->tk_status);
1193         return;
1194 out_retry:
1195         req->rq_received = req->rq_private_buf.len = 0;
1196         task->tk_status = 0;
1197         if (task->tk_client->cl_discrtry)
1198                 xprt_disconnect(task->tk_xprt);
1199 }
1200
1201 /*
1202  * 8.   Refresh the credentials if rejected by the server
1203  */
1204 static void
1205 call_refresh(struct rpc_task *task)
1206 {
1207         dprint_status(task);
1208
1209         xprt_release(task);     /* Must do to obtain new XID */
1210         task->tk_action = call_refreshresult;
1211         task->tk_status = 0;
1212         task->tk_client->cl_stats->rpcauthrefresh++;
1213         rpcauth_refreshcred(task);
1214 }
1215
1216 /*
1217  * 8a.  Process the results of a credential refresh
1218  */
1219 static void
1220 call_refreshresult(struct rpc_task *task)
1221 {
1222         int status = task->tk_status;
1223
1224         dprint_status(task);
1225
1226         task->tk_status = 0;
1227         task->tk_action = call_reserve;
1228         if (status >= 0 && rpcauth_uptodatecred(task))
1229                 return;
1230         if (status == -EACCES) {
1231                 rpc_exit(task, -EACCES);
1232                 return;
1233         }
1234         task->tk_action = call_refresh;
1235         if (status != -ETIMEDOUT)
1236                 rpc_delay(task, 3*HZ);
1237         return;
1238 }
1239
1240 /*
1241  * Call header serialization
1242  */
1243 static __be32 *
1244 call_header(struct rpc_task *task)
1245 {
1246         struct rpc_clnt *clnt = task->tk_client;
1247         struct rpc_rqst *req = task->tk_rqstp;
1248         __be32          *p = req->rq_svec[0].iov_base;
1249
1250         /* FIXME: check buffer size? */
1251
1252         p = xprt_skip_transport_header(task->tk_xprt, p);
1253         *p++ = req->rq_xid;             /* XID */
1254         *p++ = htonl(RPC_CALL);         /* CALL */
1255         *p++ = htonl(RPC_VERSION);      /* RPC version */
1256         *p++ = htonl(clnt->cl_prog);    /* program number */
1257         *p++ = htonl(clnt->cl_vers);    /* program version */
1258         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1259         p = rpcauth_marshcred(task, p);
1260         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1261         return p;
1262 }
1263
1264 /*
1265  * Reply header verification
1266  */
1267 static __be32 *
1268 call_verify(struct rpc_task *task)
1269 {
1270         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1271         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1272         __be32  *p = iov->iov_base;
1273         u32 n;
1274         int error = -EACCES;
1275
1276         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1277                 /* RFC-1014 says that the representation of XDR data must be a
1278                  * multiple of four bytes
1279                  * - if it isn't pointer subtraction in the NFS client may give
1280                  *   undefined results
1281                  */
1282                 printk(KERN_WARNING
1283                        "call_verify: XDR representation not a multiple of"
1284                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1285                 goto out_eio;
1286         }
1287         if ((len -= 3) < 0)
1288                 goto out_overflow;
1289         p += 1; /* skip XID */
1290
1291         if ((n = ntohl(*p++)) != RPC_REPLY) {
1292                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1293                 goto out_garbage;
1294         }
1295         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1296                 if (--len < 0)
1297                         goto out_overflow;
1298                 switch ((n = ntohl(*p++))) {
1299                         case RPC_AUTH_ERROR:
1300                                 break;
1301                         case RPC_MISMATCH:
1302                                 dprintk("RPC: %5u %s: RPC call version "
1303                                                 "mismatch!\n",
1304                                                 task->tk_pid, __FUNCTION__);
1305                                 error = -EPROTONOSUPPORT;
1306                                 goto out_err;
1307                         default:
1308                                 dprintk("RPC: %5u %s: RPC call rejected, "
1309                                                 "unknown error: %x\n",
1310                                                 task->tk_pid, __FUNCTION__, n);
1311                                 goto out_eio;
1312                 }
1313                 if (--len < 0)
1314                         goto out_overflow;
1315                 switch ((n = ntohl(*p++))) {
1316                 case RPC_AUTH_REJECTEDCRED:
1317                 case RPC_AUTH_REJECTEDVERF:
1318                 case RPCSEC_GSS_CREDPROBLEM:
1319                 case RPCSEC_GSS_CTXPROBLEM:
1320                         if (!task->tk_cred_retry)
1321                                 break;
1322                         task->tk_cred_retry--;
1323                         dprintk("RPC: %5u %s: retry stale creds\n",
1324                                         task->tk_pid, __FUNCTION__);
1325                         rpcauth_invalcred(task);
1326                         task->tk_action = call_refresh;
1327                         goto out_retry;
1328                 case RPC_AUTH_BADCRED:
1329                 case RPC_AUTH_BADVERF:
1330                         /* possibly garbled cred/verf? */
1331                         if (!task->tk_garb_retry)
1332                                 break;
1333                         task->tk_garb_retry--;
1334                         dprintk("RPC: %5u %s: retry garbled creds\n",
1335                                         task->tk_pid, __FUNCTION__);
1336                         task->tk_action = call_bind;
1337                         goto out_retry;
1338                 case RPC_AUTH_TOOWEAK:
1339                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1340                                "authentication.\n", task->tk_client->cl_server);
1341                         break;
1342                 default:
1343                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1344                         error = -EIO;
1345                 }
1346                 dprintk("RPC: %5u %s: call rejected %d\n",
1347                                 task->tk_pid, __FUNCTION__, n);
1348                 goto out_err;
1349         }
1350         if (!(p = rpcauth_checkverf(task, p))) {
1351                 printk(KERN_WARNING "call_verify: auth check failed\n");
1352                 goto out_garbage;               /* bad verifier, retry */
1353         }
1354         len = p - (__be32 *)iov->iov_base - 1;
1355         if (len < 0)
1356                 goto out_overflow;
1357         switch ((n = ntohl(*p++))) {
1358         case RPC_SUCCESS:
1359                 return p;
1360         case RPC_PROG_UNAVAIL:
1361                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1362                                 task->tk_pid, __FUNCTION__,
1363                                 (unsigned int)task->tk_client->cl_prog,
1364                                 task->tk_client->cl_server);
1365                 error = -EPFNOSUPPORT;
1366                 goto out_err;
1367         case RPC_PROG_MISMATCH:
1368                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1369                                 "server %s\n", task->tk_pid, __FUNCTION__,
1370                                 (unsigned int)task->tk_client->cl_prog,
1371                                 (unsigned int)task->tk_client->cl_vers,
1372                                 task->tk_client->cl_server);
1373                 error = -EPROTONOSUPPORT;
1374                 goto out_err;
1375         case RPC_PROC_UNAVAIL:
1376                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1377                                 "version %u on server %s\n",
1378                                 task->tk_pid, __FUNCTION__,
1379                                 task->tk_msg.rpc_proc,
1380                                 task->tk_client->cl_prog,
1381                                 task->tk_client->cl_vers,
1382                                 task->tk_client->cl_server);
1383                 error = -EOPNOTSUPP;
1384                 goto out_err;
1385         case RPC_GARBAGE_ARGS:
1386                 dprintk("RPC: %5u %s: server saw garbage\n",
1387                                 task->tk_pid, __FUNCTION__);
1388                 break;                  /* retry */
1389         default:
1390                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1391                 /* Also retry */
1392         }
1393
1394 out_garbage:
1395         task->tk_client->cl_stats->rpcgarbage++;
1396         if (task->tk_garb_retry) {
1397                 task->tk_garb_retry--;
1398                 dprintk("RPC: %5u %s: retrying\n",
1399                                 task->tk_pid, __FUNCTION__);
1400                 task->tk_action = call_bind;
1401 out_retry:
1402                 return ERR_PTR(-EAGAIN);
1403         }
1404         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1405 out_eio:
1406         error = -EIO;
1407 out_err:
1408         rpc_exit(task, error);
1409         return ERR_PTR(error);
1410 out_overflow:
1411         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1412         goto out_garbage;
1413 }
1414
1415 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1416 {
1417         return 0;
1418 }
1419
1420 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1421 {
1422         return 0;
1423 }
1424
1425 static struct rpc_procinfo rpcproc_null = {
1426         .p_encode = rpcproc_encode_null,
1427         .p_decode = rpcproc_decode_null,
1428 };
1429
1430 int rpc_ping(struct rpc_clnt *clnt, int flags)
1431 {
1432         struct rpc_message msg = {
1433                 .rpc_proc = &rpcproc_null,
1434         };
1435         int err;
1436         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1437         err = rpc_call_sync(clnt, &msg, flags);
1438         put_rpccred(msg.rpc_cred);
1439         return err;
1440 }