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