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 #include <linux/vs_cvirt.h>
  34
  35 #include <linux/sunrpc/clnt.h>
  36 #include <linux/sunrpc/rpc_pipe_fs.h>
  37 #include <linux/sunrpc/metrics.h>
  38
  39
  40 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  41
  42 #ifdef RPC_DEBUG
  43 # define RPCDBG_FACILITY        RPCDBG_CALL
  44 #endif
  45
  46 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  47
  48
  49 static void     call_start(struct rpc_task *task);
  50 static void     call_reserve(struct rpc_task *task);
  51 static void     call_reserveresult(struct rpc_task *task);
  52 static void     call_allocate(struct rpc_task *task);
  53 static void     call_encode(struct rpc_task *task);
  54 static void     call_decode(struct rpc_task *task);
  55 static void     call_bind(struct rpc_task *task);
  56 static void     call_bind_status(struct rpc_task *task);
  57 static void     call_transmit(struct rpc_task *task);
  58 static void     call_status(struct rpc_task *task);
  59 static void     call_transmit_status(struct rpc_task *task);
  60 static void     call_refresh(struct rpc_task *task);
  61 static void     call_refreshresult(struct rpc_task *task);
  62 static void     call_timeout(struct rpc_task *task);
  63 static void     call_connect(struct rpc_task *task);
  64 static void     call_connect_status(struct rpc_task *task);
  65 static __be32 * call_header(struct rpc_task *task);
  66 static __be32 * call_verify(struct rpc_task *task);
  67
  68
  69 static int
  70 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  71 {
  72         static uint32_t clntid;
  73         int error;
  74
  75         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  76         clnt->cl_dentry = ERR_PTR(-ENOENT);
  77         if (dir_name == NULL)
  78                 return 0;
  79
  80         clnt->cl_vfsmnt = rpc_get_mount();
  81         if (IS_ERR(clnt->cl_vfsmnt))
  82                 return PTR_ERR(clnt->cl_vfsmnt);
  83
  84         for (;;) {
  85                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  86                                 "%s/clnt%x", dir_name,
  87                                 (unsigned int)clntid++);
  88                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  89                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  90                 if (!IS_ERR(clnt->cl_dentry))
  91                         return 0;
  92                 error = PTR_ERR(clnt->cl_dentry);
  93                 if (error != -EEXIST) {
  94                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  95                                         clnt->cl_pathname, error);
  96                         rpc_put_mount();
  97                         return error;
  98                 }
  99         }
 100 }
 101
 102 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 103 {
 104         struct rpc_version      *version;
 105         struct rpc_clnt         *clnt = NULL;
 106         struct rpc_auth         *auth;
 107         int err;
 108         int len;
 109
 110         dprintk("RPC: creating %s client for %s (xprt %p)\n",
 111                 program->name, servname, xprt);
 112
 113         err = -EINVAL;
 114         if (!xprt)
 115                 goto out_no_xprt;
 116         if (vers >= program->nrvers || !(version = program->version[vers]))
 117                 goto out_err;
 118
 119         err = -ENOMEM;
 120         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 121         if (!clnt)
 122                 goto out_err;
 123         atomic_set(&clnt->cl_users, 0);
 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
 151         if (!xprt_bound(clnt->cl_xprt))
 152                 clnt->cl_autobind = 1;
 153
 154         clnt->cl_rtt = &clnt->cl_rtt_default;
 155         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 156
 157         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 158         if (err < 0)
 159                 goto out_no_path;
 160
 161         auth = rpcauth_create(flavor, clnt);
 162         if (IS_ERR(auth)) {
 163                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 164                                 flavor);
 165                 err = PTR_ERR(auth);
 166                 goto out_no_auth;
 167         }
 168
 169         /* save the nodename */
 170         clnt->cl_nodelen = strlen(utsname()->nodename);
 171         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 172                 clnt->cl_nodelen = UNX_MAXNODENAME;
 173         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 174         return clnt;
 175
 176 out_no_auth:
 177         if (!IS_ERR(clnt->cl_dentry)) {
 178                 rpc_rmdir(clnt->cl_dentry);
 179                 rpc_put_mount();
 180         }
 181 out_no_path:
 182         rpc_free_iostats(clnt->cl_metrics);
 183 out_no_stats:
 184         if (clnt->cl_server != clnt->cl_inline_name)
 185                 kfree(clnt->cl_server);
 186         kfree(clnt);
 187 out_err:
 188         xprt_put(xprt);
 189 out_no_xprt:
 190         return ERR_PTR(err);
 191 }
 192
 193 /*
 194  * rpc_create - create an RPC client and transport with one call
 195  * @args: rpc_clnt create argument structure
 196  *
 197  * Creates and initializes an RPC transport and an RPC client.
 198  *
 199  * It can ping the server in order to determine if it is up, and to see if
 200  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 201  * this behavior so asynchronous tasks can also use rpc_create.
 202  */
 203 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 204 {
 205         struct rpc_xprt *xprt;
 206         struct rpc_clnt *clnt;
 207
 208         xprt = xprt_create_transport(args->protocol, args->address,
 209                                         args->addrsize, args->timeout);
 210         if (IS_ERR(xprt))
 211                 return (struct rpc_clnt *)xprt;
 212
 213         /*
 214          * By default, kernel RPC client connects from a reserved port.
 215          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 216          * but it is always enabled for rpciod, which handles the connect
 217          * operation.
 218          */
 219         xprt->resvport = 1;
 220         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 221                 xprt->resvport = 0;
 222
 223         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 224                 args->program->name, args->servername, xprt);
 225
 226         clnt = rpc_new_client(xprt, args->servername, args->program,
 227                                 args->version, args->authflavor);
 228         if (IS_ERR(clnt))
 229                 return clnt;
 230
 231         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 232                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 233                 if (err != 0) {
 234                         rpc_shutdown_client(clnt);
 235                         return ERR_PTR(err);
 236                 }
 237         }
 238
 239         clnt->cl_softrtry = 1;
 240         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 241                 clnt->cl_softrtry = 0;
 242
 243         if (args->flags & RPC_CLNT_CREATE_INTR)
 244                 clnt->cl_intr = 1;
 245         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 246                 clnt->cl_autobind = 1;
 247         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 248                 clnt->cl_oneshot = 1;
 249         /* TODO: handle RPC_CLNT_CREATE_TAGGED
 250         if (args->flags & RPC_CLNT_CREATE_TAGGED)
 251                 clnt->cl_tag = 1; */
 252         return clnt;
 253 }
 254 EXPORT_SYMBOL_GPL(rpc_create);
 255
 256 /*
 257  * This function clones the RPC client structure. It allows us to share the
 258  * same transport while varying parameters such as the authentication
 259  * flavour.
 260  */
 261 struct rpc_clnt *
 262 rpc_clone_client(struct rpc_clnt *clnt)
 263 {
 264         struct rpc_clnt *new;
 265         int err = -ENOMEM;
 266
 267         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 268         if (!new)
 269                 goto out_no_clnt;
 270         atomic_set(&new->cl_count, 1);
 271         atomic_set(&new->cl_users, 0);
 272         new->cl_metrics = rpc_alloc_iostats(clnt);
 273         if (new->cl_metrics == NULL)
 274                 goto out_no_stats;
 275         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 276         if (err != 0)
 277                 goto out_no_path;
 278         new->cl_parent = clnt;
 279         atomic_inc(&clnt->cl_count);
 280         new->cl_xprt = xprt_get(clnt->cl_xprt);
 281         /* Turn off autobind on clones */
 282         new->cl_autobind = 0;
 283         new->cl_oneshot = 0;
 284         new->cl_dead = 0;
 285         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 286         if (new->cl_auth)
 287                 atomic_inc(&new->cl_auth->au_count);
 288         return new;
 289 out_no_path:
 290         rpc_free_iostats(new->cl_metrics);
 291 out_no_stats:
 292         kfree(new);
 293 out_no_clnt:
 294         dprintk("RPC: %s returned error %d\n", __FUNCTION__, err);
 295         return ERR_PTR(err);
 296 }
 297
 298 /*
 299  * Properly shut down an RPC client, terminating all outstanding
 300  * requests. Note that we must be certain that cl_oneshot and
 301  * cl_dead are cleared, or else the client would be destroyed
 302  * when the last task releases it.
 303  */
 304 int
 305 rpc_shutdown_client(struct rpc_clnt *clnt)
 306 {
 307         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 308                         clnt->cl_protname, clnt->cl_server,
 309                         atomic_read(&clnt->cl_users));
 310
 311         while (atomic_read(&clnt->cl_users) > 0) {
 312                 /* Don't let rpc_release_client destroy us */
 313                 clnt->cl_oneshot = 0;
 314                 clnt->cl_dead = 0;
 315                 rpc_killall_tasks(clnt);
 316                 wait_event_timeout(destroy_wait,
 317                         !atomic_read(&clnt->cl_users), 1*HZ);
 318         }
 319
 320         if (atomic_read(&clnt->cl_users) < 0) {
 321                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 322                                 clnt, atomic_read(&clnt->cl_users));
 323 #ifdef RPC_DEBUG
 324                 rpc_show_tasks();
 325 #endif
 326                 BUG();
 327         }
 328
 329         return rpc_destroy_client(clnt);
 330 }
 331
 332 /*
 333  * Delete an RPC client
 334  */
 335 int
 336 rpc_destroy_client(struct rpc_clnt *clnt)
 337 {
 338         if (!atomic_dec_and_test(&clnt->cl_count))
 339                 return 1;
 340         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 341
 342         dprintk("RPC: destroying %s client for %s\n",
 343                         clnt->cl_protname, clnt->cl_server);
 344         if (clnt->cl_auth) {
 345                 rpcauth_destroy(clnt->cl_auth);
 346                 clnt->cl_auth = NULL;
 347         }
 348         if (!IS_ERR(clnt->cl_dentry)) {
 349                 rpc_rmdir(clnt->cl_dentry);
 350                 rpc_put_mount();
 351         }
 352         if (clnt->cl_parent != clnt) {
 353                 rpc_destroy_client(clnt->cl_parent);
 354                 goto out_free;
 355         }
 356         if (clnt->cl_server != clnt->cl_inline_name)
 357                 kfree(clnt->cl_server);
 358 out_free:
 359         rpc_free_iostats(clnt->cl_metrics);
 360         clnt->cl_metrics = NULL;
 361         xprt_put(clnt->cl_xprt);
 362         kfree(clnt);
 363         return 0;
 364 }
 365
 366 /*
 367  * Release an RPC client
 368  */
 369 void
 370 rpc_release_client(struct rpc_clnt *clnt)
 371 {
 372         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 373                                 clnt, atomic_read(&clnt->cl_users));
 374
 375         if (!atomic_dec_and_test(&clnt->cl_users))
 376                 return;
 377         wake_up(&destroy_wait);
 378         if (clnt->cl_oneshot || clnt->cl_dead)
 379                 rpc_destroy_client(clnt);
 380 }
 381
 382 /**
 383  * rpc_bind_new_program - bind a new RPC program to an existing client
 384  * @old - old rpc_client
 385  * @program - rpc program to set
 386  * @vers - rpc program version
 387  *
 388  * Clones the rpc client and sets up a new RPC program. This is mainly
 389  * of use for enabling different RPC programs to share the same transport.
 390  * The Sun NFSv2/v3 ACL protocol can do this.
 391  */
 392 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 393                                       struct rpc_program *program,
 394                                       int vers)
 395 {
 396         struct rpc_clnt *clnt;
 397         struct rpc_version *version;
 398         int err;
 399
 400         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 401         version = program->version[vers];
 402         clnt = rpc_clone_client(old);
 403         if (IS_ERR(clnt))
 404                 goto out;
 405         clnt->cl_procinfo = version->procs;
 406         clnt->cl_maxproc  = version->nrprocs;
 407         clnt->cl_protname = program->name;
 408         clnt->cl_prog     = program->number;
 409         clnt->cl_vers     = version->number;
 410         clnt->cl_stats    = program->stats;
 411         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 412         if (err != 0) {
 413                 rpc_shutdown_client(clnt);
 414                 clnt = ERR_PTR(err);
 415         }
 416 out:
 417         return clnt;
 418 }
 419
 420 /*
 421  * Default callback for async RPC calls
 422  */
 423 static void
 424 rpc_default_callback(struct rpc_task *task, void *data)
 425 {
 426 }
 427
 428 static const struct rpc_call_ops rpc_default_ops = {
 429         .rpc_call_done = rpc_default_callback,
 430 };
 431
 432 /*
 433  *      Export the signal mask handling for synchronous code that
 434  *      sleeps on RPC calls
 435  */
 436 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 437
 438 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 439 {
 440         unsigned long   sigallow = sigmask(SIGKILL);
 441         sigset_t sigmask;
 442
 443         /* Block all signals except those listed in sigallow */
 444         if (intr)
 445                 sigallow |= RPC_INTR_SIGNALS;
 446         siginitsetinv(&sigmask, sigallow);
 447         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 448 }
 449
 450 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 451 {
 452         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 453 }
 454
 455 static inline void rpc_restore_sigmask(sigset_t *oldset)
 456 {
 457         sigprocmask(SIG_SETMASK, oldset, NULL);
 458 }
 459
 460 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 461 {
 462         rpc_save_sigmask(oldset, clnt->cl_intr);
 463 }
 464
 465 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 466 {
 467         rpc_restore_sigmask(oldset);
 468 }
 469
 470 /*
 471  * New rpc_call implementation
 472  */
 473 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 474 {
 475         struct rpc_task *task;
 476         sigset_t        oldset;
 477         int             status;
 478
 479         /* If this client is slain all further I/O fails */
 480         if (clnt->cl_dead)
 481                 return -EIO;
 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         rpc_call_setup(task, msg, 0);
 493
 494         /* Set up the call info struct and execute the task */
 495         status = task->tk_status;
 496         if (status != 0)
 497                 goto out;
 498         atomic_inc(&task->tk_count);
 499         status = rpc_execute(task);
 500         if (status == 0)
 501                 status = task->tk_status;
 502 out:
 503         rpc_put_task(task);
 504         rpc_restore_sigmask(&oldset);
 505         return status;
 506 }
 507
 508 /*
 509  * New rpc_call implementation
 510  */
 511 int
 512 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 513                const struct rpc_call_ops *tk_ops, void *data)
 514 {
 515         struct rpc_task *task;
 516         sigset_t        oldset;
 517         int             status;
 518
 519         /* If this client is slain all further I/O fails */
 520         status = -EIO;
 521         if (clnt->cl_dead)
 522                 goto out_release;
 523
 524         flags |= RPC_TASK_ASYNC;
 525
 526         /* Create/initialize a new RPC task */
 527         status = -ENOMEM;
 528         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 529                 goto out_release;
 530
 531         /* Mask signals on GSS_AUTH upcalls */
 532         rpc_task_sigmask(task, &oldset);
 533
 534         rpc_call_setup(task, msg, 0);
 535
 536         /* Set up the call info struct and execute the task */
 537         status = task->tk_status;
 538         if (status == 0)
 539                 rpc_execute(task);
 540         else
 541                 rpc_put_task(task);
 542
 543         rpc_restore_sigmask(&oldset);
 544         return status;
 545 out_release:
 546         rpc_release_calldata(tk_ops, data);
 547         return status;
 548 }
 549
 550
 551 void
 552 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 553 {
 554         task->tk_msg   = *msg;
 555         task->tk_flags |= flags;
 556         /* Bind the user cred */
 557         if (task->tk_msg.rpc_cred != NULL)
 558                 rpcauth_holdcred(task);
 559         else
 560                 rpcauth_bindcred(task);
 561
 562         if (task->tk_status == 0)
 563                 task->tk_action = call_start;
 564         else
 565                 task->tk_action = rpc_exit_task;
 566 }
 567
 568 /**
 569  * rpc_peeraddr - extract remote peer address from clnt's xprt
 570  * @clnt: RPC client structure
 571  * @buf: target buffer
 572  * @size: length of target buffer
 573  *
 574  * Returns the number of bytes that are actually in the stored address.
 575  */
 576 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 577 {
 578         size_t bytes;
 579         struct rpc_xprt *xprt = clnt->cl_xprt;
 580
 581         bytes = sizeof(xprt->addr);
 582         if (bytes > bufsize)
 583                 bytes = bufsize;
 584         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 585         return xprt->addrlen;
 586 }
 587 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 588
 589 /**
 590  * rpc_peeraddr2str - return remote peer address in printable format
 591  * @clnt: RPC client structure
 592  * @format: address format
 593  *
 594  */
 595 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 596 {
 597         struct rpc_xprt *xprt = clnt->cl_xprt;
 598
 599         if (xprt->address_strings[format] != NULL)
 600                 return xprt->address_strings[format];
 601         else
 602                 return "unprintable";
 603 }
 604 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 605
 606 void
 607 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 608 {
 609         struct rpc_xprt *xprt = clnt->cl_xprt;
 610         if (xprt->ops->set_buffer_size)
 611                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 612 }
 613
 614 /*
 615  * Return size of largest payload RPC client can support, in bytes
 616  *
 617  * For stream transports, this is one RPC record fragment (see RFC
 618  * 1831), as we don't support multi-record requests yet.  For datagram
 619  * transports, this is the size of an IP packet minus the IP, UDP, and
 620  * RPC header sizes.
 621  */
 622 size_t rpc_max_payload(struct rpc_clnt *clnt)
 623 {
 624         return clnt->cl_xprt->max_payload;
 625 }
 626 EXPORT_SYMBOL_GPL(rpc_max_payload);
 627
 628 /**
 629  * rpc_force_rebind - force transport to check that remote port is unchanged
 630  * @clnt: client to rebind
 631  *
 632  */
 633 void rpc_force_rebind(struct rpc_clnt *clnt)
 634 {
 635         if (clnt->cl_autobind)
 636                 xprt_clear_bound(clnt->cl_xprt);
 637 }
 638 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 639
 640 /*
 641  * Restart an (async) RPC call. Usually called from within the
 642  * exit handler.
 643  */
 644 void
 645 rpc_restart_call(struct rpc_task *task)
 646 {
 647         if (RPC_ASSASSINATED(task))
 648                 return;
 649
 650         task->tk_action = call_start;
 651 }
 652
 653 /*
 654  * 0.  Initial state
 655  *
 656  *     Other FSM states can be visited zero or more times, but
 657  *     this state is visited exactly once for each RPC.
 658  */
 659 static void
 660 call_start(struct rpc_task *task)
 661 {
 662         struct rpc_clnt *clnt = task->tk_client;
 663
 664         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 665                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 666                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 667
 668         /* Increment call count */
 669         task->tk_msg.rpc_proc->p_count++;
 670         clnt->cl_stats->rpccnt++;
 671         task->tk_action = call_reserve;
 672 }
 673
 674 /*
 675  * 1.   Reserve an RPC call slot
 676  */
 677 static void
 678 call_reserve(struct rpc_task *task)
 679 {
 680         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 681
 682         if (!rpcauth_uptodatecred(task)) {
 683                 task->tk_action = call_refresh;
 684                 return;
 685         }
 686
 687         task->tk_status  = 0;
 688         task->tk_action  = call_reserveresult;
 689         xprt_reserve(task);
 690 }
 691
 692 /*
 693  * 1b.  Grok the result of xprt_reserve()
 694  */
 695 static void
 696 call_reserveresult(struct rpc_task *task)
 697 {
 698         int status = task->tk_status;
 699
 700         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 701                                 task->tk_pid, task->tk_status);
 702
 703         /*
 704          * After a call to xprt_reserve(), we must have either
 705          * a request slot or else an error status.
 706          */
 707         task->tk_status = 0;
 708         if (status >= 0) {
 709                 if (task->tk_rqstp) {
 710                         task->tk_action = call_allocate;
 711                         return;
 712                 }
 713
 714                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 715                                 __FUNCTION__, status);
 716                 rpc_exit(task, -EIO);
 717                 return;
 718         }
 719
 720         /*
 721          * Even though there was an error, we may have acquired
 722          * a request slot somehow.  Make sure not to leak it.
 723          */
 724         if (task->tk_rqstp) {
 725                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 726                                 __FUNCTION__, status);
 727                 xprt_release(task);
 728         }
 729
 730         switch (status) {
 731         case -EAGAIN:   /* woken up; retry */
 732                 task->tk_action = call_reserve;
 733                 return;
 734         case -EIO:      /* probably a shutdown */
 735                 break;
 736         default:
 737                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 738                                 __FUNCTION__, status);
 739                 break;
 740         }
 741         rpc_exit(task, status);
 742 }
 743
 744 /*
 745  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 746  *      (Note: buffer memory is freed in xprt_release).
 747  */
 748 static void
 749 call_allocate(struct rpc_task *task)
 750 {
 751         struct rpc_rqst *req = task->tk_rqstp;
 752         struct rpc_xprt *xprt = task->tk_xprt;
 753         unsigned int    bufsiz;
 754
 755         dprintk("RPC: %4d call_allocate (status %d)\n",
 756                                 task->tk_pid, task->tk_status);
 757         task->tk_action = call_bind;
 758         if (req->rq_buffer)
 759                 return;
 760
 761         /* FIXME: compute buffer requirements more exactly using
 762          * auth->au_wslack */
 763         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 764
 765         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 766                 return;
 767         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 768
 769         if (RPC_IS_ASYNC(task) || !signalled()) {
 770                 xprt_release(task);
 771                 task->tk_action = call_reserve;
 772                 rpc_delay(task, HZ>>4);
 773                 return;
 774         }
 775
 776         rpc_exit(task, -ERESTARTSYS);
 777 }
 778
 779 static inline int
 780 rpc_task_need_encode(struct rpc_task *task)
 781 {
 782         return task->tk_rqstp->rq_snd_buf.len == 0;
 783 }
 784
 785 static inline void
 786 rpc_task_force_reencode(struct rpc_task *task)
 787 {
 788         task->tk_rqstp->rq_snd_buf.len = 0;
 789 }
 790
 791 /*
 792  * 3.   Encode arguments of an RPC call
 793  */
 794 static void
 795 call_encode(struct rpc_task *task)
 796 {
 797         struct rpc_rqst *req = task->tk_rqstp;
 798         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 799         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 800         unsigned int    bufsiz;
 801         kxdrproc_t      encode;
 802         __be32          *p;
 803
 804         dprintk("RPC: %4d call_encode (status %d)\n",
 805                                 task->tk_pid, task->tk_status);
 806
 807         /* Default buffer setup */
 808         bufsiz = req->rq_bufsize >> 1;
 809         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 810         sndbuf->head[0].iov_len  = bufsiz;
 811         sndbuf->tail[0].iov_len  = 0;
 812         sndbuf->page_len         = 0;
 813         sndbuf->len              = 0;
 814         sndbuf->buflen           = bufsiz;
 815         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 816         rcvbuf->head[0].iov_len  = bufsiz;
 817         rcvbuf->tail[0].iov_len  = 0;
 818         rcvbuf->page_len         = 0;
 819         rcvbuf->len              = 0;
 820         rcvbuf->buflen           = bufsiz;
 821
 822         /* Encode header and provided arguments */
 823         encode = task->tk_msg.rpc_proc->p_encode;
 824         if (!(p = call_header(task))) {
 825                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 826                 rpc_exit(task, -EIO);
 827                 return;
 828         }
 829         if (encode == NULL)
 830                 return;
 831
 832         lock_kernel();
 833         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 834                         task->tk_msg.rpc_argp);
 835         unlock_kernel();
 836         if (task->tk_status == -ENOMEM) {
 837                 /* XXX: Is this sane? */
 838                 rpc_delay(task, 3*HZ);
 839                 task->tk_status = -EAGAIN;
 840         }
 841 }
 842
 843 /*
 844  * 4.   Get the server port number if not yet set
 845  */
 846 static void
 847 call_bind(struct rpc_task *task)
 848 {
 849         struct rpc_xprt *xprt = task->tk_xprt;
 850
 851         dprintk("RPC: %4d call_bind (status %d)\n",
 852                                 task->tk_pid, task->tk_status);
 853
 854         task->tk_action = call_connect;
 855         if (!xprt_bound(xprt)) {
 856                 task->tk_action = call_bind_status;
 857                 task->tk_timeout = xprt->bind_timeout;
 858                 xprt->ops->rpcbind(task);
 859         }
 860 }
 861
 862 /*
 863  * 4a.  Sort out bind result
 864  */
 865 static void
 866 call_bind_status(struct rpc_task *task)
 867 {
 868         int status = -EACCES;
 869
 870         if (task->tk_status >= 0) {
 871                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 872                                         task->tk_pid, task->tk_status);
 873                 task->tk_status = 0;
 874                 task->tk_action = call_connect;
 875                 return;
 876         }
 877
 878         switch (task->tk_status) {
 879         case -EACCES:
 880                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 881                                 task->tk_pid);
 882                 rpc_delay(task, 3*HZ);
 883                 goto retry_timeout;
 884         case -ETIMEDOUT:
 885                 dprintk("RPC: %4d rpcbind request timed out\n",
 886                                 task->tk_pid);
 887                 goto retry_timeout;
 888         case -EPFNOSUPPORT:
 889                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 890                                 task->tk_pid);
 891                 break;
 892         case -EPROTONOSUPPORT:
 893                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 894                                 task->tk_pid);
 895                 break;
 896         default:
 897                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 898                                 task->tk_pid, -task->tk_status);
 899                 status = -EIO;
 900         }
 901
 902         rpc_exit(task, status);
 903         return;
 904
 905 retry_timeout:
 906         task->tk_action = call_timeout;
 907 }
 908
 909 /*
 910  * 4b.  Connect to the RPC server
 911  */
 912 static void
 913 call_connect(struct rpc_task *task)
 914 {
 915         struct rpc_xprt *xprt = task->tk_xprt;
 916
 917         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 918                         task->tk_pid, xprt,
 919                         (xprt_connected(xprt) ? "is" : "is not"));
 920
 921         task->tk_action = call_transmit;
 922         if (!xprt_connected(xprt)) {
 923                 task->tk_action = call_connect_status;
 924                 if (task->tk_status < 0)
 925                         return;
 926                 xprt_connect(task);
 927         }
 928 }
 929
 930 /*
 931  * 4c.  Sort out connect result
 932  */
 933 static void
 934 call_connect_status(struct rpc_task *task)
 935 {
 936         struct rpc_clnt *clnt = task->tk_client;
 937         int status = task->tk_status;
 938
 939         dprintk("RPC: %5u call_connect_status (status %d)\n",
 940                                 task->tk_pid, task->tk_status);
 941
 942         task->tk_status = 0;
 943         if (status >= 0) {
 944                 clnt->cl_stats->netreconn++;
 945                 task->tk_action = call_transmit;
 946                 return;
 947         }
 948
 949         /* Something failed: remote service port may have changed */
 950         rpc_force_rebind(clnt);
 951
 952         switch (status) {
 953         case -ENOTCONN:
 954         case -EAGAIN:
 955                 task->tk_action = call_bind;
 956                 if (!RPC_IS_SOFT(task))
 957                         return;
 958                 /* if soft mounted, test if we've timed out */
 959         case -ETIMEDOUT:
 960                 task->tk_action = call_timeout;
 961                 return;
 962         }
 963         rpc_exit(task, -EIO);
 964 }
 965
 966 /*
 967  * 5.   Transmit the RPC request, and wait for reply
 968  */
 969 static void
 970 call_transmit(struct rpc_task *task)
 971 {
 972         dprintk("RPC: %4d call_transmit (status %d)\n",
 973                                 task->tk_pid, task->tk_status);
 974
 975         task->tk_action = call_status;
 976         if (task->tk_status < 0)
 977                 return;
 978         task->tk_status = xprt_prepare_transmit(task);
 979         if (task->tk_status != 0)
 980                 return;
 981         task->tk_action = call_transmit_status;
 982         /* Encode here so that rpcsec_gss can use correct sequence number. */
 983         if (rpc_task_need_encode(task)) {
 984                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 985                 call_encode(task);
 986                 /* Did the encode result in an error condition? */
 987                 if (task->tk_status != 0)
 988                         return;
 989         }
 990         xprt_transmit(task);
 991         if (task->tk_status < 0)
 992                 return;
 993         /*
 994          * On success, ensure that we call xprt_end_transmit() before sleeping
 995          * in order to allow access to the socket to other RPC requests.
 996          */
 997         call_transmit_status(task);
 998         if (task->tk_msg.rpc_proc->p_decode != NULL)
 999                 return;
1000         task->tk_action = rpc_exit_task;
1001         rpc_wake_up_task(task);
1002 }
1003
1004 /*
1005  * 5a.  Handle cleanup after a transmission
1006  */
1007 static void
1008 call_transmit_status(struct rpc_task *task)
1009 {
1010         task->tk_action = call_status;
1011         /*
1012          * Special case: if we've been waiting on the socket's write_space()
1013          * callback, then don't call xprt_end_transmit().
1014          */
1015         if (task->tk_status == -EAGAIN)
1016                 return;
1017         xprt_end_transmit(task);
1018         rpc_task_force_reencode(task);
1019 }
1020
1021 /*
1022  * 6.   Sort out the RPC call status
1023  */
1024 static void
1025 call_status(struct rpc_task *task)
1026 {
1027         struct rpc_clnt *clnt = task->tk_client;
1028         struct rpc_rqst *req = task->tk_rqstp;
1029         int             status;
1030
1031         if (req->rq_received > 0 && !req->rq_bytes_sent)
1032                 task->tk_status = req->rq_received;
1033
1034         dprintk("RPC: %4d call_status (status %d)\n",
1035                                 task->tk_pid, task->tk_status);
1036
1037         status = task->tk_status;
1038         if (status >= 0) {
1039                 task->tk_action = call_decode;
1040                 return;
1041         }
1042
1043         task->tk_status = 0;
1044         switch(status) {
1045         case -EHOSTDOWN:
1046         case -EHOSTUNREACH:
1047         case -ENETUNREACH:
1048                 /*
1049                  * Delay any retries for 3 seconds, then handle as if it
1050                  * were a timeout.
1051                  */
1052                 rpc_delay(task, 3*HZ);
1053         case -ETIMEDOUT:
1054                 task->tk_action = call_timeout;
1055                 break;
1056         case -ECONNREFUSED:
1057         case -ENOTCONN:
1058                 rpc_force_rebind(clnt);
1059                 task->tk_action = call_bind;
1060                 break;
1061         case -EAGAIN:
1062                 task->tk_action = call_transmit;
1063                 break;
1064         case -EIO:
1065                 /* shutdown or soft timeout */
1066                 rpc_exit(task, status);
1067                 break;
1068         default:
1069                 printk("%s: RPC call returned error %d\n",
1070                                clnt->cl_protname, -status);
1071                 rpc_exit(task, status);
1072         }
1073 }
1074
1075 /*
1076  * 6a.  Handle RPC timeout
1077  *      We do not release the request slot, so we keep using the
1078  *      same XID for all retransmits.
1079  */
1080 static void
1081 call_timeout(struct rpc_task *task)
1082 {
1083         struct rpc_clnt *clnt = task->tk_client;
1084
1085         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1086                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1087                 goto retry;
1088         }
1089
1090         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1091         task->tk_timeouts++;
1092
1093         if (RPC_IS_SOFT(task)) {
1094                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1095                                 clnt->cl_protname, clnt->cl_server);
1096                 rpc_exit(task, -EIO);
1097                 return;
1098         }
1099
1100         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1101                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1102                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1103                         clnt->cl_protname, clnt->cl_server);
1104         }
1105         rpc_force_rebind(clnt);
1106
1107 retry:
1108         clnt->cl_stats->rpcretrans++;
1109         task->tk_action = call_bind;
1110         task->tk_status = 0;
1111 }
1112
1113 /*
1114  * 7.   Decode the RPC reply
1115  */
1116 static void
1117 call_decode(struct rpc_task *task)
1118 {
1119         struct rpc_clnt *clnt = task->tk_client;
1120         struct rpc_rqst *req = task->tk_rqstp;
1121         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1122         __be32          *p;
1123
1124         dprintk("RPC: %4d call_decode (status %d)\n",
1125                                 task->tk_pid, task->tk_status);
1126
1127         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1128                 printk(KERN_NOTICE "%s: server %s OK\n",
1129                         clnt->cl_protname, clnt->cl_server);
1130                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1131         }
1132
1133         if (task->tk_status < 12) {
1134                 if (!RPC_IS_SOFT(task)) {
1135                         task->tk_action = call_bind;
1136                         clnt->cl_stats->rpcretrans++;
1137                         goto out_retry;
1138                 }
1139                 dprintk("%s: too small RPC reply size (%d bytes)\n",
1140                         clnt->cl_protname, task->tk_status);
1141                 task->tk_action = call_timeout;
1142                 goto out_retry;
1143         }
1144
1145         /*
1146          * Ensure that we see all writes made by xprt_complete_rqst()
1147          * before it changed req->rq_received.
1148          */
1149         smp_rmb();
1150         req->rq_rcv_buf.len = req->rq_private_buf.len;
1151
1152         /* Check that the softirq receive buffer is valid */
1153         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1154                                 sizeof(req->rq_rcv_buf)) != 0);
1155
1156         /* Verify the RPC header */
1157         p = call_verify(task);
1158         if (IS_ERR(p)) {
1159                 if (p == ERR_PTR(-EAGAIN))
1160                         goto out_retry;
1161                 return;
1162         }
1163
1164         task->tk_action = rpc_exit_task;
1165
1166         if (decode) {
1167                 lock_kernel();
1168                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1169                                                       task->tk_msg.rpc_resp);
1170                 unlock_kernel();
1171         }
1172         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1173                                         task->tk_status);
1174         return;
1175 out_retry:
1176         req->rq_received = req->rq_private_buf.len = 0;
1177         task->tk_status = 0;
1178 }
1179
1180 /*
1181  * 8.   Refresh the credentials if rejected by the server
1182  */
1183 static void
1184 call_refresh(struct rpc_task *task)
1185 {
1186         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1187
1188         xprt_release(task);     /* Must do to obtain new XID */
1189         task->tk_action = call_refreshresult;
1190         task->tk_status = 0;
1191         task->tk_client->cl_stats->rpcauthrefresh++;
1192         rpcauth_refreshcred(task);
1193 }
1194
1195 /*
1196  * 8a.  Process the results of a credential refresh
1197  */
1198 static void
1199 call_refreshresult(struct rpc_task *task)
1200 {
1201         int status = task->tk_status;
1202         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1203                                 task->tk_pid, task->tk_status);
1204
1205         task->tk_status = 0;
1206         task->tk_action = call_reserve;
1207         if (status >= 0 && rpcauth_uptodatecred(task))
1208                 return;
1209         if (status == -EACCES) {
1210                 rpc_exit(task, -EACCES);
1211                 return;
1212         }
1213         task->tk_action = call_refresh;
1214         if (status != -ETIMEDOUT)
1215                 rpc_delay(task, 3*HZ);
1216         return;
1217 }
1218
1219 /*
1220  * Call header serialization
1221  */
1222 static __be32 *
1223 call_header(struct rpc_task *task)
1224 {
1225         struct rpc_clnt *clnt = task->tk_client;
1226         struct rpc_rqst *req = task->tk_rqstp;
1227         __be32          *p = req->rq_svec[0].iov_base;
1228
1229         /* FIXME: check buffer size? */
1230
1231         p = xprt_skip_transport_header(task->tk_xprt, p);
1232         *p++ = req->rq_xid;             /* XID */
1233         *p++ = htonl(RPC_CALL);         /* CALL */
1234         *p++ = htonl(RPC_VERSION);      /* RPC version */
1235         *p++ = htonl(clnt->cl_prog);    /* program number */
1236         *p++ = htonl(clnt->cl_vers);    /* program version */
1237         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1238         p = rpcauth_marshcred(task, p);
1239         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1240         return p;
1241 }
1242
1243 /*
1244  * Reply header verification
1245  */
1246 static __be32 *
1247 call_verify(struct rpc_task *task)
1248 {
1249         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1250         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1251         __be32  *p = iov->iov_base;
1252         u32 n;
1253         int error = -EACCES;
1254
1255         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1256                 /* RFC-1014 says that the representation of XDR data must be a
1257                  * multiple of four bytes
1258                  * - if it isn't pointer subtraction in the NFS client may give
1259                  *   undefined results
1260                  */
1261                 printk(KERN_WARNING
1262                        "call_verify: XDR representation not a multiple of"
1263                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1264                 goto out_eio;
1265         }
1266         if ((len -= 3) < 0)
1267                 goto out_overflow;
1268         p += 1; /* skip XID */
1269
1270         if ((n = ntohl(*p++)) != RPC_REPLY) {
1271                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1272                 goto out_garbage;
1273         }
1274         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1275                 if (--len < 0)
1276                         goto out_overflow;
1277                 switch ((n = ntohl(*p++))) {
1278                         case RPC_AUTH_ERROR:
1279                                 break;
1280                         case RPC_MISMATCH:
1281                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1282                                 error = -EPROTONOSUPPORT;
1283                                 goto out_err;
1284                         default:
1285                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1286                                 goto out_eio;
1287                 }
1288                 if (--len < 0)
1289                         goto out_overflow;
1290                 switch ((n = ntohl(*p++))) {
1291                 case RPC_AUTH_REJECTEDCRED:
1292                 case RPC_AUTH_REJECTEDVERF:
1293                 case RPCSEC_GSS_CREDPROBLEM:
1294                 case RPCSEC_GSS_CTXPROBLEM:
1295                         if (!task->tk_cred_retry)
1296                                 break;
1297                         task->tk_cred_retry--;
1298                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1299                                                         task->tk_pid);
1300                         rpcauth_invalcred(task);
1301                         task->tk_action = call_refresh;
1302                         goto out_retry;
1303                 case RPC_AUTH_BADCRED:
1304                 case RPC_AUTH_BADVERF:
1305                         /* possibly garbled cred/verf? */
1306                         if (!task->tk_garb_retry)
1307                                 break;
1308                         task->tk_garb_retry--;
1309                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1310                                                         task->tk_pid);
1311                         task->tk_action = call_bind;
1312                         goto out_retry;
1313                 case RPC_AUTH_TOOWEAK:
1314                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1315                                "authentication.\n", task->tk_client->cl_server);
1316                         break;
1317                 default:
1318                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1319                         error = -EIO;
1320                 }
1321                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1322                                                 task->tk_pid, n);
1323                 goto out_err;
1324         }
1325         if (!(p = rpcauth_checkverf(task, p))) {
1326                 printk(KERN_WARNING "call_verify: auth check failed\n");
1327                 goto out_garbage;               /* bad verifier, retry */
1328         }
1329         len = p - (__be32 *)iov->iov_base - 1;
1330         if (len < 0)
1331                 goto out_overflow;
1332         switch ((n = ntohl(*p++))) {
1333         case RPC_SUCCESS:
1334                 return p;
1335         case RPC_PROG_UNAVAIL:
1336                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1337                                 (unsigned int)task->tk_client->cl_prog,
1338                                 task->tk_client->cl_server);
1339                 error = -EPFNOSUPPORT;
1340                 goto out_err;
1341         case RPC_PROG_MISMATCH:
1342                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1343                                 (unsigned int)task->tk_client->cl_prog,
1344                                 (unsigned int)task->tk_client->cl_vers,
1345                                 task->tk_client->cl_server);
1346                 error = -EPROTONOSUPPORT;
1347                 goto out_err;
1348         case RPC_PROC_UNAVAIL:
1349                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1350                                 task->tk_msg.rpc_proc,
1351                                 task->tk_client->cl_prog,
1352                                 task->tk_client->cl_vers,
1353                                 task->tk_client->cl_server);
1354                 error = -EOPNOTSUPP;
1355                 goto out_err;
1356         case RPC_GARBAGE_ARGS:
1357                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1358                 break;                  /* retry */
1359         default:
1360                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1361                 /* Also retry */
1362         }
1363
1364 out_garbage:
1365         task->tk_client->cl_stats->rpcgarbage++;
1366         if (task->tk_garb_retry) {
1367                 task->tk_garb_retry--;
1368                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1369                 task->tk_action = call_bind;
1370 out_retry:
1371                 return ERR_PTR(-EAGAIN);
1372         }
1373         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1374 out_eio:
1375         error = -EIO;
1376 out_err:
1377         rpc_exit(task, error);
1378         return ERR_PTR(error);
1379 out_overflow:
1380         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1381         goto out_garbage;
1382 }
1383
1384 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1385 {
1386         return 0;
1387 }
1388
1389 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1390 {
1391         return 0;
1392 }
1393
1394 static struct rpc_procinfo rpcproc_null = {
1395         .p_encode = rpcproc_encode_null,
1396         .p_decode = rpcproc_decode_null,
1397 };
1398
1399 int rpc_ping(struct rpc_clnt *clnt, int flags)
1400 {
1401         struct rpc_message msg = {
1402                 .rpc_proc = &rpcproc_null,
1403         };
1404         int err;
1405         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1406         err = rpc_call_sync(clnt, &msg, flags);
1407         put_rpccred(msg.rpc_cred);
1408         return err;
1409 }