net/sunrpc/clnt.c

   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <[email protected]>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <[email protected]>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/kallsyms.h>
  29 #include <linux/mm.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/slab.h>
  33 #include <linux/utsname.h>
  34 #include <linux/workqueue.h>
  35 #include <linux/in6.h>
  36
  37 #include <linux/sunrpc/clnt.h>
  38 #include <linux/sunrpc/rpc_pipe_fs.h>
  39 #include <linux/sunrpc/metrics.h>
  40 #include <linux/sunrpc/bc_xprt.h>
  41
  42 #include "sunrpc.h"
  43
  44 #ifdef RPC_DEBUG
  45 # define RPCDBG_FACILITY        RPCDBG_CALL
  46 #endif
  47
  48 #define dprint_status(t)                                        \
  49         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  50                         __func__, t->tk_status)
  51
  52 /*
  53  * All RPC clients are linked into this list
  54  */
  55 static LIST_HEAD(all_clients);
  56 static DEFINE_SPINLOCK(rpc_client_lock);
  57
  58 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  59
  60
  61 static void     call_start(struct rpc_task *task);
  62 static void     call_reserve(struct rpc_task *task);
  63 static void     call_reserveresult(struct rpc_task *task);
  64 static void     call_allocate(struct rpc_task *task);
  65 static void     call_decode(struct rpc_task *task);
  66 static void     call_bind(struct rpc_task *task);
  67 static void     call_bind_status(struct rpc_task *task);
  68 static void     call_transmit(struct rpc_task *task);
  69 #if defined(CONFIG_NFS_V4_1)
  70 static void     call_bc_transmit(struct rpc_task *task);
  71 #endif /* CONFIG_NFS_V4_1 */
  72 static void     call_status(struct rpc_task *task);
  73 static void     call_transmit_status(struct rpc_task *task);
  74 static void     call_refresh(struct rpc_task *task);
  75 static void     call_refreshresult(struct rpc_task *task);
  76 static void     call_timeout(struct rpc_task *task);
  77 static void     call_connect(struct rpc_task *task);
  78 static void     call_connect_status(struct rpc_task *task);
  79
  80 static __be32   *rpc_encode_header(struct rpc_task *task);
  81 static __be32   *rpc_verify_header(struct rpc_task *task);
  82 static int      rpc_ping(struct rpc_clnt *clnt);
  83
  84 static void rpc_register_client(struct rpc_clnt *clnt)
  85 {
  86         spin_lock(&rpc_client_lock);
  87         list_add(&clnt->cl_clients, &all_clients);
  88         spin_unlock(&rpc_client_lock);
  89 }
  90
  91 static void rpc_unregister_client(struct rpc_clnt *clnt)
  92 {
  93         spin_lock(&rpc_client_lock);
  94         list_del(&clnt->cl_clients);
  95         spin_unlock(&rpc_client_lock);
  96 }
  97
  98 static int
  99 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
 100 {
 101         static uint32_t clntid;
 102         struct nameidata nd;
 103         struct path path;
 104         char name[15];
 105         struct qstr q = {
 106                 .name = name,
 107         };
 108         int error;
 109
 110         clnt->cl_path.mnt = ERR_PTR(-ENOENT);
 111         clnt->cl_path.dentry = ERR_PTR(-ENOENT);
 112         if (dir_name == NULL)
 113                 return 0;
 114
 115         path.mnt = rpc_get_mount();
 116         if (IS_ERR(path.mnt))
 117                 return PTR_ERR(path.mnt);
 118         error = vfs_path_lookup(path.mnt->mnt_root, path.mnt, dir_name, 0, &nd);
 119         if (error)
 120                 goto err;
 121
 122         for (;;) {
 123                 q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
 124                 name[sizeof(name) - 1] = '\0';
 125                 q.hash = full_name_hash(q.name, q.len);
 126                 path.dentry = rpc_create_client_dir(nd.path.dentry, &q, clnt);
 127                 if (!IS_ERR(path.dentry))
 128                         break;
 129                 error = PTR_ERR(path.dentry);
 130                 if (error != -EEXIST) {
 131                         printk(KERN_INFO "RPC: Couldn't create pipefs entry"
 132                                         " %s/%s, error %d\n",
 133                                         dir_name, name, error);
 134                         goto err_path_put;
 135                 }
 136         }
 137         path_put(&nd.path);
 138         clnt->cl_path = path;
 139         return 0;
 140 err_path_put:
 141         path_put(&nd.path);
 142 err:
 143         rpc_put_mount();
 144         return error;
 145 }
 146
 147 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
 148 {
 149         struct rpc_program      *program = args->program;
 150         struct rpc_version      *version;
 151         struct rpc_clnt         *clnt = NULL;
 152         struct rpc_auth         *auth;
 153         int err;
 154         size_t len;
 155
 156         /* sanity check the name before trying to print it */
 157         err = -EINVAL;
 158         len = strlen(args->servername);
 159         if (len > RPC_MAXNETNAMELEN)
 160                 goto out_no_rpciod;
 161         len++;
 162
 163         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 164                         program->name, args->servername, xprt);
 165
 166         err = rpciod_up();
 167         if (err)
 168                 goto out_no_rpciod;
 169         err = -EINVAL;
 170         if (!xprt)
 171                 goto out_no_xprt;
 172
 173         if (args->version >= program->nrvers)
 174                 goto out_err;
 175         version = program->version[args->version];
 176         if (version == NULL)
 177                 goto out_err;
 178
 179         err = -ENOMEM;
 180         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 181         if (!clnt)
 182                 goto out_err;
 183         clnt->cl_parent = clnt;
 184
 185         clnt->cl_server = clnt->cl_inline_name;
 186         if (len > sizeof(clnt->cl_inline_name)) {
 187                 char *buf = kmalloc(len, GFP_KERNEL);
 188                 if (buf != NULL)
 189                         clnt->cl_server = buf;
 190                 else
 191                         len = sizeof(clnt->cl_inline_name);
 192         }
 193         strlcpy(clnt->cl_server, args->servername, len);
 194
 195         clnt->cl_xprt     = xprt;
 196         clnt->cl_procinfo = version->procs;
 197         clnt->cl_maxproc  = version->nrprocs;
 198         clnt->cl_protname = program->name;
 199         clnt->cl_prog     = args->prognumber ? : program->number;
 200         clnt->cl_vers     = version->number;
 201         clnt->cl_stats    = program->stats;
 202         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 203         err = -ENOMEM;
 204         if (clnt->cl_metrics == NULL)
 205                 goto out_no_stats;
 206         clnt->cl_program  = program;
 207         INIT_LIST_HEAD(&clnt->cl_tasks);
 208         spin_lock_init(&clnt->cl_lock);
 209
 210         if (!xprt_bound(clnt->cl_xprt))
 211                 clnt->cl_autobind = 1;
 212
 213         clnt->cl_timeout = xprt->timeout;
 214         if (args->timeout != NULL) {
 215                 memcpy(&clnt->cl_timeout_default, args->timeout,
 216                                 sizeof(clnt->cl_timeout_default));
 217                 clnt->cl_timeout = &clnt->cl_timeout_default;
 218         }
 219
 220         clnt->cl_rtt = &clnt->cl_rtt_default;
 221         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 222         clnt->cl_principal = NULL;
 223         if (args->client_name) {
 224                 clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
 225                 if (!clnt->cl_principal)
 226                         goto out_no_principal;
 227         }
 228
 229         atomic_set(&clnt->cl_count, 1);
 230
 231         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 232         if (err < 0)
 233                 goto out_no_path;
 234
 235         auth = rpcauth_create(args->authflavor, clnt);
 236         if (IS_ERR(auth)) {
 237                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 238                                 args->authflavor);
 239                 err = PTR_ERR(auth);
 240                 goto out_no_auth;
 241         }
 242
 243         /* save the nodename */
 244         clnt->cl_nodelen = strlen(init_utsname()->nodename);
 245         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 246                 clnt->cl_nodelen = UNX_MAXNODENAME;
 247         memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen);
 248         rpc_register_client(clnt);
 249         return clnt;
 250
 251 out_no_auth:
 252         if (!IS_ERR(clnt->cl_path.dentry)) {
 253                 rpc_remove_client_dir(clnt->cl_path.dentry);
 254                 rpc_put_mount();
 255         }
 256 out_no_path:
 257         kfree(clnt->cl_principal);
 258 out_no_principal:
 259         rpc_free_iostats(clnt->cl_metrics);
 260 out_no_stats:
 261         if (clnt->cl_server != clnt->cl_inline_name)
 262                 kfree(clnt->cl_server);
 263         kfree(clnt);
 264 out_err:
 265         xprt_put(xprt);
 266 out_no_xprt:
 267         rpciod_down();
 268 out_no_rpciod:
 269         return ERR_PTR(err);
 270 }
 271
 272 /*
 273  * rpc_create - create an RPC client and transport with one call
 274  * @args: rpc_clnt create argument structure
 275  *
 276  * Creates and initializes an RPC transport and an RPC client.
 277  *
 278  * It can ping the server in order to determine if it is up, and to see if
 279  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 280  * this behavior so asynchronous tasks can also use rpc_create.
 281  */
 282 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 283 {
 284         struct rpc_xprt *xprt;
 285         struct rpc_clnt *clnt;
 286         struct xprt_create xprtargs = {
 287                 .net = args->net,
 288                 .ident = args->protocol,
 289                 .srcaddr = args->saddress,
 290                 .dstaddr = args->address,
 291                 .addrlen = args->addrsize,
 292                 .bc_xprt = args->bc_xprt,
 293         };
 294         char servername[48];
 295
 296         /*
 297          * If the caller chooses not to specify a hostname, whip
 298          * up a string representation of the passed-in address.
 299          */
 300         if (args->servername == NULL) {
 301                 servername[0] = '\0';
 302                 switch (args->address->sa_family) {
 303                 case AF_INET: {
 304                         struct sockaddr_in *sin =
 305                                         (struct sockaddr_in *)args->address;
 306                         snprintf(servername, sizeof(servername), "%pI4",
 307                                  &sin->sin_addr.s_addr);
 308                         break;
 309                 }
 310                 case AF_INET6: {
 311                         struct sockaddr_in6 *sin =
 312                                         (struct sockaddr_in6 *)args->address;
 313                         snprintf(servername, sizeof(servername), "%pI6",
 314                                  &sin->sin6_addr);
 315                         break;
 316                 }
 317                 default:
 318                         /* caller wants default server name, but
 319                          * address family isn't recognized. */
 320                         return ERR_PTR(-EINVAL);
 321                 }
 322                 args->servername = servername;
 323         }
 324
 325         xprt = xprt_create_transport(&xprtargs);
 326         if (IS_ERR(xprt))
 327                 return (struct rpc_clnt *)xprt;
 328
 329         /*
 330          * By default, kernel RPC client connects from a reserved port.
 331          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 332          * but it is always enabled for rpciod, which handles the connect
 333          * operation.
 334          */
 335         xprt->resvport = 1;
 336         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 337                 xprt->resvport = 0;
 338
 339         clnt = rpc_new_client(args, xprt);
 340         if (IS_ERR(clnt))
 341                 return clnt;
 342
 343         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 344                 int err = rpc_ping(clnt);
 345                 if (err != 0) {
 346                         rpc_shutdown_client(clnt);
 347                         return ERR_PTR(err);
 348                 }
 349         }
 350
 351         clnt->cl_softrtry = 1;
 352         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 353                 clnt->cl_softrtry = 0;
 354
 355         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 356                 clnt->cl_autobind = 1;
 357         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 358                 clnt->cl_discrtry = 1;
 359         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 360                 clnt->cl_chatty = 1;
 361
 362         return clnt;
 363 }
 364 EXPORT_SYMBOL_GPL(rpc_create);
 365
 366 /*
 367  * This function clones the RPC client structure. It allows us to share the
 368  * same transport while varying parameters such as the authentication
 369  * flavour.
 370  */
 371 struct rpc_clnt *
 372 rpc_clone_client(struct rpc_clnt *clnt)
 373 {
 374         struct rpc_clnt *new;
 375         int err = -ENOMEM;
 376
 377         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 378         if (!new)
 379                 goto out_no_clnt;
 380         new->cl_parent = clnt;
 381         /* Turn off autobind on clones */
 382         new->cl_autobind = 0;
 383         INIT_LIST_HEAD(&new->cl_tasks);
 384         spin_lock_init(&new->cl_lock);
 385         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
 386         new->cl_metrics = rpc_alloc_iostats(clnt);
 387         if (new->cl_metrics == NULL)
 388                 goto out_no_stats;
 389         if (clnt->cl_principal) {
 390                 new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
 391                 if (new->cl_principal == NULL)
 392                         goto out_no_principal;
 393         }
 394         atomic_set(&new->cl_count, 1);
 395         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 396         if (err != 0)
 397                 goto out_no_path;
 398         if (new->cl_auth)
 399                 atomic_inc(&new->cl_auth->au_count);
 400         xprt_get(clnt->cl_xprt);
 401         atomic_inc(&clnt->cl_count);
 402         rpc_register_client(new);
 403         rpciod_up();
 404         return new;
 405 out_no_path:
 406         kfree(new->cl_principal);
 407 out_no_principal:
 408         rpc_free_iostats(new->cl_metrics);
 409 out_no_stats:
 410         kfree(new);
 411 out_no_clnt:
 412         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 413         return ERR_PTR(err);
 414 }
 415 EXPORT_SYMBOL_GPL(rpc_clone_client);
 416
 417 /*
 418  * Kill all tasks for the given client.
 419  * XXX: kill their descendants as well?
 420  */
 421 void rpc_killall_tasks(struct rpc_clnt *clnt)
 422 {
 423         struct rpc_task *rovr;
 424
 425
 426         if (list_empty(&clnt->cl_tasks))
 427                 return;
 428         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 429         /*
 430          * Spin lock all_tasks to prevent changes...
 431          */
 432         spin_lock(&clnt->cl_lock);
 433         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 434                 if (!RPC_IS_ACTIVATED(rovr))
 435                         continue;
 436                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 437                         rovr->tk_flags |= RPC_TASK_KILLED;
 438                         rpc_exit(rovr, -EIO);
 439                         rpc_wake_up_queued_task(rovr->tk_waitqueue, rovr);
 440                 }
 441         }
 442         spin_unlock(&clnt->cl_lock);
 443 }
 444 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 445
 446 /*
 447  * Properly shut down an RPC client, terminating all outstanding
 448  * requests.
 449  */
 450 void rpc_shutdown_client(struct rpc_clnt *clnt)
 451 {
 452         dprintk("RPC:       shutting down %s client for %s\n",
 453                         clnt->cl_protname, clnt->cl_server);
 454
 455         while (!list_empty(&clnt->cl_tasks)) {
 456                 rpc_killall_tasks(clnt);
 457                 wait_event_timeout(destroy_wait,
 458                         list_empty(&clnt->cl_tasks), 1*HZ);
 459         }
 460
 461         rpc_release_client(clnt);
 462 }
 463 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 464
 465 /*
 466  * Free an RPC client
 467  */
 468 static void
 469 rpc_free_client(struct rpc_clnt *clnt)
 470 {
 471         dprintk("RPC:       destroying %s client for %s\n",
 472                         clnt->cl_protname, clnt->cl_server);
 473         if (!IS_ERR(clnt->cl_path.dentry)) {
 474                 rpc_remove_client_dir(clnt->cl_path.dentry);
 475                 rpc_put_mount();
 476         }
 477         if (clnt->cl_parent != clnt) {
 478                 rpc_release_client(clnt->cl_parent);
 479                 goto out_free;
 480         }
 481         if (clnt->cl_server != clnt->cl_inline_name)
 482                 kfree(clnt->cl_server);
 483 out_free:
 484         rpc_unregister_client(clnt);
 485         rpc_free_iostats(clnt->cl_metrics);
 486         kfree(clnt->cl_principal);
 487         clnt->cl_metrics = NULL;
 488         xprt_put(clnt->cl_xprt);
 489         rpciod_down();
 490         kfree(clnt);
 491 }
 492
 493 /*
 494  * Free an RPC client
 495  */
 496 static void
 497 rpc_free_auth(struct rpc_clnt *clnt)
 498 {
 499         if (clnt->cl_auth == NULL) {
 500                 rpc_free_client(clnt);
 501                 return;
 502         }
 503
 504         /*
 505          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 506          *       release remaining GSS contexts. This mechanism ensures
 507          *       that it can do so safely.
 508          */
 509         atomic_inc(&clnt->cl_count);
 510         rpcauth_release(clnt->cl_auth);
 511         clnt->cl_auth = NULL;
 512         if (atomic_dec_and_test(&clnt->cl_count))
 513                 rpc_free_client(clnt);
 514 }
 515
 516 /*
 517  * Release reference to the RPC client
 518  */
 519 void
 520 rpc_release_client(struct rpc_clnt *clnt)
 521 {
 522         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 523
 524         if (list_empty(&clnt->cl_tasks))
 525                 wake_up(&destroy_wait);
 526         if (atomic_dec_and_test(&clnt->cl_count))
 527                 rpc_free_auth(clnt);
 528 }
 529
 530 /**
 531  * rpc_bind_new_program - bind a new RPC program to an existing client
 532  * @old: old rpc_client
 533  * @program: rpc program to set
 534  * @vers: rpc program version
 535  *
 536  * Clones the rpc client and sets up a new RPC program. This is mainly
 537  * of use for enabling different RPC programs to share the same transport.
 538  * The Sun NFSv2/v3 ACL protocol can do this.
 539  */
 540 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 541                                       struct rpc_program *program,
 542                                       u32 vers)
 543 {
 544         struct rpc_clnt *clnt;
 545         struct rpc_version *version;
 546         int err;
 547
 548         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 549         version = program->version[vers];
 550         clnt = rpc_clone_client(old);
 551         if (IS_ERR(clnt))
 552                 goto out;
 553         clnt->cl_procinfo = version->procs;
 554         clnt->cl_maxproc  = version->nrprocs;
 555         clnt->cl_protname = program->name;
 556         clnt->cl_prog     = program->number;
 557         clnt->cl_vers     = version->number;
 558         clnt->cl_stats    = program->stats;
 559         err = rpc_ping(clnt);
 560         if (err != 0) {
 561                 rpc_shutdown_client(clnt);
 562                 clnt = ERR_PTR(err);
 563         }
 564 out:
 565         return clnt;
 566 }
 567 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 568
 569 void rpc_task_release_client(struct rpc_task *task)
 570 {
 571         struct rpc_clnt *clnt = task->tk_client;
 572
 573         if (clnt != NULL) {
 574                 /* Remove from client task list */
 575                 spin_lock(&clnt->cl_lock);
 576                 list_del(&task->tk_task);
 577                 spin_unlock(&clnt->cl_lock);
 578                 task->tk_client = NULL;
 579
 580                 rpc_release_client(clnt);
 581         }
 582 }
 583
 584 static
 585 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 586 {
 587         if (clnt != NULL) {
 588                 rpc_task_release_client(task);
 589                 task->tk_client = clnt;
 590                 atomic_inc(&clnt->cl_count);
 591                 if (clnt->cl_softrtry)
 592                         task->tk_flags |= RPC_TASK_SOFT;
 593                 /* Add to the client's list of all tasks */
 594                 spin_lock(&clnt->cl_lock);
 595                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 596                 spin_unlock(&clnt->cl_lock);
 597         }
 598 }
 599
 600 static void
 601 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 602 {
 603         if (msg != NULL) {
 604                 task->tk_msg.rpc_proc = msg->rpc_proc;
 605                 task->tk_msg.rpc_argp = msg->rpc_argp;
 606                 task->tk_msg.rpc_resp = msg->rpc_resp;
 607                 if (msg->rpc_cred != NULL)
 608                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 609         }
 610 }
 611
 612 /*
 613  * Default callback for async RPC calls
 614  */
 615 static void
 616 rpc_default_callback(struct rpc_task *task, void *data)
 617 {
 618 }
 619
 620 static const struct rpc_call_ops rpc_default_ops = {
 621         .rpc_call_done = rpc_default_callback,
 622 };
 623
 624 /**
 625  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 626  * @task_setup_data: pointer to task initialisation data
 627  */
 628 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 629 {
 630         struct rpc_task *task;
 631
 632         task = rpc_new_task(task_setup_data);
 633         if (IS_ERR(task))
 634                 goto out;
 635
 636         rpc_task_set_client(task, task_setup_data->rpc_client);
 637         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 638
 639         if (task->tk_status != 0) {
 640                 int ret = task->tk_status;
 641                 rpc_put_task(task);
 642                 return ERR_PTR(ret);
 643         }
 644
 645         if (task->tk_action == NULL)
 646                 rpc_call_start(task);
 647
 648         atomic_inc(&task->tk_count);
 649         rpc_execute(task);
 650 out:
 651         return task;
 652 }
 653 EXPORT_SYMBOL_GPL(rpc_run_task);
 654
 655 /**
 656  * rpc_call_sync - Perform a synchronous RPC call
 657  * @clnt: pointer to RPC client
 658  * @msg: RPC call parameters
 659  * @flags: RPC call flags
 660  */
 661 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 662 {
 663         struct rpc_task *task;
 664         struct rpc_task_setup task_setup_data = {
 665                 .rpc_client = clnt,
 666                 .rpc_message = msg,
 667                 .callback_ops = &rpc_default_ops,
 668                 .flags = flags,
 669         };
 670         int status;
 671
 672         BUG_ON(flags & RPC_TASK_ASYNC);
 673
 674         task = rpc_run_task(&task_setup_data);
 675         if (IS_ERR(task))
 676                 return PTR_ERR(task);
 677         status = task->tk_status;
 678         rpc_put_task(task);
 679         return status;
 680 }
 681 EXPORT_SYMBOL_GPL(rpc_call_sync);
 682
 683 /**
 684  * rpc_call_async - Perform an asynchronous RPC call
 685  * @clnt: pointer to RPC client
 686  * @msg: RPC call parameters
 687  * @flags: RPC call flags
 688  * @tk_ops: RPC call ops
 689  * @data: user call data
 690  */
 691 int
 692 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 693                const struct rpc_call_ops *tk_ops, void *data)
 694 {
 695         struct rpc_task *task;
 696         struct rpc_task_setup task_setup_data = {
 697                 .rpc_client = clnt,
 698                 .rpc_message = msg,
 699                 .callback_ops = tk_ops,
 700                 .callback_data = data,
 701                 .flags = flags|RPC_TASK_ASYNC,
 702         };
 703
 704         task = rpc_run_task(&task_setup_data);
 705         if (IS_ERR(task))
 706                 return PTR_ERR(task);
 707         rpc_put_task(task);
 708         return 0;
 709 }
 710 EXPORT_SYMBOL_GPL(rpc_call_async);
 711
 712 #if defined(CONFIG_NFS_V4_1)
 713 /**
 714  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
 715  * rpc_execute against it
 716  * @req: RPC request
 717  * @tk_ops: RPC call ops
 718  */
 719 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
 720                                 const struct rpc_call_ops *tk_ops)
 721 {
 722         struct rpc_task *task;
 723         struct xdr_buf *xbufp = &req->rq_snd_buf;
 724         struct rpc_task_setup task_setup_data = {
 725                 .callback_ops = tk_ops,
 726         };
 727
 728         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
 729         /*
 730          * Create an rpc_task to send the data
 731          */
 732         task = rpc_new_task(&task_setup_data);
 733         if (IS_ERR(task)) {
 734                 xprt_free_bc_request(req);
 735                 goto out;
 736         }
 737         task->tk_rqstp = req;
 738
 739         /*
 740          * Set up the xdr_buf length.
 741          * This also indicates that the buffer is XDR encoded already.
 742          */
 743         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
 744                         xbufp->tail[0].iov_len;
 745
 746         task->tk_action = call_bc_transmit;
 747         atomic_inc(&task->tk_count);
 748         BUG_ON(atomic_read(&task->tk_count) != 2);
 749         rpc_execute(task);
 750
 751 out:
 752         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
 753         return task;
 754 }
 755 #endif /* CONFIG_NFS_V4_1 */
 756
 757 void
 758 rpc_call_start(struct rpc_task *task)
 759 {
 760         task->tk_action = call_start;
 761 }
 762 EXPORT_SYMBOL_GPL(rpc_call_start);
 763
 764 /**
 765  * rpc_peeraddr - extract remote peer address from clnt's xprt
 766  * @clnt: RPC client structure
 767  * @buf: target buffer
 768  * @bufsize: length of target buffer
 769  *
 770  * Returns the number of bytes that are actually in the stored address.
 771  */
 772 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 773 {
 774         size_t bytes;
 775         struct rpc_xprt *xprt = clnt->cl_xprt;
 776
 777         bytes = sizeof(xprt->addr);
 778         if (bytes > bufsize)
 779                 bytes = bufsize;
 780         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 781         return xprt->addrlen;
 782 }
 783 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 784
 785 /**
 786  * rpc_peeraddr2str - return remote peer address in printable format
 787  * @clnt: RPC client structure
 788  * @format: address format
 789  *
 790  */
 791 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
 792                              enum rpc_display_format_t format)
 793 {
 794         struct rpc_xprt *xprt = clnt->cl_xprt;
 795
 796         if (xprt->address_strings[format] != NULL)
 797                 return xprt->address_strings[format];
 798         else
 799                 return "unprintable";
 800 }
 801 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 802
 803 void
 804 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 805 {
 806         struct rpc_xprt *xprt = clnt->cl_xprt;
 807         if (xprt->ops->set_buffer_size)
 808                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 809 }
 810 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 811
 812 /*
 813  * Return size of largest payload RPC client can support, in bytes
 814  *
 815  * For stream transports, this is one RPC record fragment (see RFC
 816  * 1831), as we don't support multi-record requests yet.  For datagram
 817  * transports, this is the size of an IP packet minus the IP, UDP, and
 818  * RPC header sizes.
 819  */
 820 size_t rpc_max_payload(struct rpc_clnt *clnt)
 821 {
 822         return clnt->cl_xprt->max_payload;
 823 }
 824 EXPORT_SYMBOL_GPL(rpc_max_payload);
 825
 826 /**
 827  * rpc_force_rebind - force transport to check that remote port is unchanged
 828  * @clnt: client to rebind
 829  *
 830  */
 831 void rpc_force_rebind(struct rpc_clnt *clnt)
 832 {
 833         if (clnt->cl_autobind)
 834                 xprt_clear_bound(clnt->cl_xprt);
 835 }
 836 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 837
 838 /*
 839  * Restart an (async) RPC call from the call_prepare state.
 840  * Usually called from within the exit handler.
 841  */
 842 int
 843 rpc_restart_call_prepare(struct rpc_task *task)
 844 {
 845         if (RPC_ASSASSINATED(task))
 846                 return 0;
 847         task->tk_action = rpc_prepare_task;
 848         return 1;
 849 }
 850 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
 851
 852 /*
 853  * Restart an (async) RPC call. Usually called from within the
 854  * exit handler.
 855  */
 856 int
 857 rpc_restart_call(struct rpc_task *task)
 858 {
 859         if (RPC_ASSASSINATED(task))
 860                 return 0;
 861         task->tk_action = call_start;
 862         return 1;
 863 }
 864 EXPORT_SYMBOL_GPL(rpc_restart_call);
 865
 866 #ifdef RPC_DEBUG
 867 static const char *rpc_proc_name(const struct rpc_task *task)
 868 {
 869         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 870
 871         if (proc) {
 872                 if (proc->p_name)
 873                         return proc->p_name;
 874                 else
 875                         return "NULL";
 876         } else
 877                 return "no proc";
 878 }
 879 #endif
 880
 881 /*
 882  * 0.  Initial state
 883  *
 884  *     Other FSM states can be visited zero or more times, but
 885  *     this state is visited exactly once for each RPC.
 886  */
 887 static void
 888 call_start(struct rpc_task *task)
 889 {
 890         struct rpc_clnt *clnt = task->tk_client;
 891
 892         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
 893                         clnt->cl_protname, clnt->cl_vers,
 894                         rpc_proc_name(task),
 895                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 896
 897         /* Increment call count */
 898         task->tk_msg.rpc_proc->p_count++;
 899         clnt->cl_stats->rpccnt++;
 900         task->tk_action = call_reserve;
 901 }
 902
 903 /*
 904  * 1.   Reserve an RPC call slot
 905  */
 906 static void
 907 call_reserve(struct rpc_task *task)
 908 {
 909         dprint_status(task);
 910
 911         task->tk_status  = 0;
 912         task->tk_action  = call_reserveresult;
 913         xprt_reserve(task);
 914 }
 915
 916 /*
 917  * 1b.  Grok the result of xprt_reserve()
 918  */
 919 static void
 920 call_reserveresult(struct rpc_task *task)
 921 {
 922         int status = task->tk_status;
 923
 924         dprint_status(task);
 925
 926         /*
 927          * After a call to xprt_reserve(), we must have either
 928          * a request slot or else an error status.
 929          */
 930         task->tk_status = 0;
 931         if (status >= 0) {
 932                 if (task->tk_rqstp) {
 933                         task->tk_action = call_refresh;
 934                         return;
 935                 }
 936
 937                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 938                                 __func__, status);
 939                 rpc_exit(task, -EIO);
 940                 return;
 941         }
 942
 943         /*
 944          * Even though there was an error, we may have acquired
 945          * a request slot somehow.  Make sure not to leak it.
 946          */
 947         if (task->tk_rqstp) {
 948                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 949                                 __func__, status);
 950                 xprt_release(task);
 951         }
 952
 953         switch (status) {
 954         case -EAGAIN:   /* woken up; retry */
 955                 task->tk_action = call_reserve;
 956                 return;
 957         case -EIO:      /* probably a shutdown */
 958                 break;
 959         default:
 960                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 961                                 __func__, status);
 962                 break;
 963         }
 964         rpc_exit(task, status);
 965 }
 966
 967 /*
 968  * 2.   Bind and/or refresh the credentials
 969  */
 970 static void
 971 call_refresh(struct rpc_task *task)
 972 {
 973         dprint_status(task);
 974
 975         task->tk_action = call_refreshresult;
 976         task->tk_status = 0;
 977         task->tk_client->cl_stats->rpcauthrefresh++;
 978         rpcauth_refreshcred(task);
 979 }
 980
 981 /*
 982  * 2a.  Process the results of a credential refresh
 983  */
 984 static void
 985 call_refreshresult(struct rpc_task *task)
 986 {
 987         int status = task->tk_status;
 988
 989         dprint_status(task);
 990
 991         task->tk_status = 0;
 992         task->tk_action = call_refresh;
 993         switch (status) {
 994         case 0:
 995                 if (rpcauth_uptodatecred(task))
 996                         task->tk_action = call_allocate;
 997                 return;
 998         case -ETIMEDOUT:
 999                 rpc_delay(task, 3*HZ);
1000         case -EAGAIN:
1001                 status = -EACCES;
1002                 if (!task->tk_cred_retry)
1003                         break;
1004                 task->tk_cred_retry--;
1005                 dprintk("RPC: %5u %s: retry refresh creds\n",
1006                                 task->tk_pid, __func__);
1007                 return;
1008         }
1009         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1010                                 task->tk_pid, __func__, status);
1011         rpc_exit(task, status);
1012 }
1013
1014 /*
1015  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1016  *      (Note: buffer memory is freed in xprt_release).
1017  */
1018 static void
1019 call_allocate(struct rpc_task *task)
1020 {
1021         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1022         struct rpc_rqst *req = task->tk_rqstp;
1023         struct rpc_xprt *xprt = task->tk_xprt;
1024         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1025
1026         dprint_status(task);
1027
1028         task->tk_status = 0;
1029         task->tk_action = call_bind;
1030
1031         if (req->rq_buffer)
1032                 return;
1033
1034         if (proc->p_proc != 0) {
1035                 BUG_ON(proc->p_arglen == 0);
1036                 if (proc->p_decode != NULL)
1037                         BUG_ON(proc->p_replen == 0);
1038         }
1039
1040         /*
1041          * Calculate the size (in quads) of the RPC call
1042          * and reply headers, and convert both values
1043          * to byte sizes.
1044          */
1045         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1046         req->rq_callsize <<= 2;
1047         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1048         req->rq_rcvsize <<= 2;
1049
1050         req->rq_buffer = xprt->ops->buf_alloc(task,
1051                                         req->rq_callsize + req->rq_rcvsize);
1052         if (req->rq_buffer != NULL)
1053                 return;
1054
1055         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1056
1057         if (RPC_IS_ASYNC(task) || !signalled()) {
1058                 task->tk_action = call_allocate;
1059                 rpc_delay(task, HZ>>4);
1060                 return;
1061         }
1062
1063         rpc_exit(task, -ERESTARTSYS);
1064 }
1065
1066 static inline int
1067 rpc_task_need_encode(struct rpc_task *task)
1068 {
1069         return task->tk_rqstp->rq_snd_buf.len == 0;
1070 }
1071
1072 static inline void
1073 rpc_task_force_reencode(struct rpc_task *task)
1074 {
1075         task->tk_rqstp->rq_snd_buf.len = 0;
1076         task->tk_rqstp->rq_bytes_sent = 0;
1077 }
1078
1079 static inline void
1080 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1081 {
1082         buf->head[0].iov_base = start;
1083         buf->head[0].iov_len = len;
1084         buf->tail[0].iov_len = 0;
1085         buf->page_len = 0;
1086         buf->flags = 0;
1087         buf->len = 0;
1088         buf->buflen = len;
1089 }
1090
1091 /*
1092  * 3.   Encode arguments of an RPC call
1093  */
1094 static void
1095 rpc_xdr_encode(struct rpc_task *task)
1096 {
1097         struct rpc_rqst *req = task->tk_rqstp;
1098         kxdrproc_t      encode;
1099         __be32          *p;
1100
1101         dprint_status(task);
1102
1103         rpc_xdr_buf_init(&req->rq_snd_buf,
1104                          req->rq_buffer,
1105                          req->rq_callsize);
1106         rpc_xdr_buf_init(&req->rq_rcv_buf,
1107                          (char *)req->rq_buffer + req->rq_callsize,
1108                          req->rq_rcvsize);
1109
1110         p = rpc_encode_header(task);
1111         if (p == NULL) {
1112                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1113                 rpc_exit(task, -EIO);
1114                 return;
1115         }
1116
1117         encode = task->tk_msg.rpc_proc->p_encode;
1118         if (encode == NULL)
1119                 return;
1120
1121         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1122                         task->tk_msg.rpc_argp);
1123 }
1124
1125 /*
1126  * 4.   Get the server port number if not yet set
1127  */
1128 static void
1129 call_bind(struct rpc_task *task)
1130 {
1131         struct rpc_xprt *xprt = task->tk_xprt;
1132
1133         dprint_status(task);
1134
1135         task->tk_action = call_connect;
1136         if (!xprt_bound(xprt)) {
1137                 task->tk_action = call_bind_status;
1138                 task->tk_timeout = xprt->bind_timeout;
1139                 xprt->ops->rpcbind(task);
1140         }
1141 }
1142
1143 /*
1144  * 4a.  Sort out bind result
1145  */
1146 static void
1147 call_bind_status(struct rpc_task *task)
1148 {
1149         int status = -EIO;
1150
1151         if (task->tk_status >= 0) {
1152                 dprint_status(task);
1153                 task->tk_status = 0;
1154                 task->tk_action = call_connect;
1155                 return;
1156         }
1157
1158         switch (task->tk_status) {
1159         case -ENOMEM:
1160                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1161                 rpc_delay(task, HZ >> 2);
1162                 goto retry_timeout;
1163         case -EACCES:
1164                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1165                                 "unavailable\n", task->tk_pid);
1166                 /* fail immediately if this is an RPC ping */
1167                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1168                         status = -EOPNOTSUPP;
1169                         break;
1170                 }
1171                 rpc_delay(task, 3*HZ);
1172                 goto retry_timeout;
1173         case -ETIMEDOUT:
1174                 dprintk("RPC: %5u rpcbind request timed out\n",
1175                                 task->tk_pid);
1176                 goto retry_timeout;
1177         case -EPFNOSUPPORT:
1178                 /* server doesn't support any rpcbind version we know of */
1179                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1180                                 task->tk_pid);
1181                 break;
1182         case -EPROTONOSUPPORT:
1183                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1184                                 task->tk_pid);
1185                 task->tk_status = 0;
1186                 task->tk_action = call_bind;
1187                 return;
1188         case -ECONNREFUSED:             /* connection problems */
1189         case -ECONNRESET:
1190         case -ENOTCONN:
1191         case -EHOSTDOWN:
1192         case -EHOSTUNREACH:
1193         case -ENETUNREACH:
1194         case -EPIPE:
1195                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1196                                 task->tk_pid, task->tk_status);
1197                 if (!RPC_IS_SOFTCONN(task)) {
1198                         rpc_delay(task, 5*HZ);
1199                         goto retry_timeout;
1200                 }
1201                 status = task->tk_status;
1202                 break;
1203         default:
1204                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1205                                 task->tk_pid, -task->tk_status);
1206         }
1207
1208         rpc_exit(task, status);
1209         return;
1210
1211 retry_timeout:
1212         task->tk_action = call_timeout;
1213 }
1214
1215 /*
1216  * 4b.  Connect to the RPC server
1217  */
1218 static void
1219 call_connect(struct rpc_task *task)
1220 {
1221         struct rpc_xprt *xprt = task->tk_xprt;
1222
1223         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1224                         task->tk_pid, xprt,
1225                         (xprt_connected(xprt) ? "is" : "is not"));
1226
1227         task->tk_action = call_transmit;
1228         if (!xprt_connected(xprt)) {
1229                 task->tk_action = call_connect_status;
1230                 if (task->tk_status < 0)
1231                         return;
1232                 xprt_connect(task);
1233         }
1234 }
1235
1236 /*
1237  * 4c.  Sort out connect result
1238  */
1239 static void
1240 call_connect_status(struct rpc_task *task)
1241 {
1242         struct rpc_clnt *clnt = task->tk_client;
1243         int status = task->tk_status;
1244
1245         dprint_status(task);
1246
1247         task->tk_status = 0;
1248         if (status >= 0 || status == -EAGAIN) {
1249                 clnt->cl_stats->netreconn++;
1250                 task->tk_action = call_transmit;
1251                 return;
1252         }
1253
1254         switch (status) {
1255                 /* if soft mounted, test if we've timed out */
1256         case -ETIMEDOUT:
1257                 task->tk_action = call_timeout;
1258                 break;
1259         default:
1260                 rpc_exit(task, -EIO);
1261         }
1262 }
1263
1264 /*
1265  * 5.   Transmit the RPC request, and wait for reply
1266  */
1267 static void
1268 call_transmit(struct rpc_task *task)
1269 {
1270         dprint_status(task);
1271
1272         task->tk_action = call_status;
1273         if (task->tk_status < 0)
1274                 return;
1275         task->tk_status = xprt_prepare_transmit(task);
1276         if (task->tk_status != 0)
1277                 return;
1278         task->tk_action = call_transmit_status;
1279         /* Encode here so that rpcsec_gss can use correct sequence number. */
1280         if (rpc_task_need_encode(task)) {
1281                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1282                 rpc_xdr_encode(task);
1283                 /* Did the encode result in an error condition? */
1284                 if (task->tk_status != 0) {
1285                         /* Was the error nonfatal? */
1286                         if (task->tk_status == -EAGAIN)
1287                                 rpc_delay(task, HZ >> 4);
1288                         else
1289                                 rpc_exit(task, task->tk_status);
1290                         return;
1291                 }
1292         }
1293         xprt_transmit(task);
1294         if (task->tk_status < 0)
1295                 return;
1296         /*
1297          * On success, ensure that we call xprt_end_transmit() before sleeping
1298          * in order to allow access to the socket to other RPC requests.
1299          */
1300         call_transmit_status(task);
1301         if (rpc_reply_expected(task))
1302                 return;
1303         task->tk_action = rpc_exit_task;
1304         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1305 }
1306
1307 /*
1308  * 5a.  Handle cleanup after a transmission
1309  */
1310 static void
1311 call_transmit_status(struct rpc_task *task)
1312 {
1313         task->tk_action = call_status;
1314
1315         /*
1316          * Common case: success.  Force the compiler to put this
1317          * test first.
1318          */
1319         if (task->tk_status == 0) {
1320                 xprt_end_transmit(task);
1321                 rpc_task_force_reencode(task);
1322                 return;
1323         }
1324
1325         switch (task->tk_status) {
1326         case -EAGAIN:
1327                 break;
1328         default:
1329                 dprint_status(task);
1330                 xprt_end_transmit(task);
1331                 rpc_task_force_reencode(task);
1332                 break;
1333                 /*
1334                  * Special cases: if we've been waiting on the
1335                  * socket's write_space() callback, or if the
1336                  * socket just returned a connection error,
1337                  * then hold onto the transport lock.
1338                  */
1339         case -ECONNREFUSED:
1340         case -EHOSTDOWN:
1341         case -EHOSTUNREACH:
1342         case -ENETUNREACH:
1343                 if (RPC_IS_SOFTCONN(task)) {
1344                         xprt_end_transmit(task);
1345                         rpc_exit(task, task->tk_status);
1346                         break;
1347                 }
1348         case -ECONNRESET:
1349         case -ENOTCONN:
1350         case -EPIPE:
1351                 rpc_task_force_reencode(task);
1352         }
1353 }
1354
1355 #if defined(CONFIG_NFS_V4_1)
1356 /*
1357  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1358  * addition, disconnect on connectivity errors.
1359  */
1360 static void
1361 call_bc_transmit(struct rpc_task *task)
1362 {
1363         struct rpc_rqst *req = task->tk_rqstp;
1364
1365         BUG_ON(task->tk_status != 0);
1366         task->tk_status = xprt_prepare_transmit(task);
1367         if (task->tk_status == -EAGAIN) {
1368                 /*
1369                  * Could not reserve the transport. Try again after the
1370                  * transport is released.
1371                  */
1372                 task->tk_status = 0;
1373                 task->tk_action = call_bc_transmit;
1374                 return;
1375         }
1376
1377         task->tk_action = rpc_exit_task;
1378         if (task->tk_status < 0) {
1379                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1380                         "error: %d\n", task->tk_status);
1381                 return;
1382         }
1383
1384         xprt_transmit(task);
1385         xprt_end_transmit(task);
1386         dprint_status(task);
1387         switch (task->tk_status) {
1388         case 0:
1389                 /* Success */
1390                 break;
1391         case -EHOSTDOWN:
1392         case -EHOSTUNREACH:
1393         case -ENETUNREACH:
1394         case -ETIMEDOUT:
1395                 /*
1396                  * Problem reaching the server.  Disconnect and let the
1397                  * forechannel reestablish the connection.  The server will
1398                  * have to retransmit the backchannel request and we'll
1399                  * reprocess it.  Since these ops are idempotent, there's no
1400                  * need to cache our reply at this time.
1401                  */
1402                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1403                         "error: %d\n", task->tk_status);
1404                 xprt_conditional_disconnect(task->tk_xprt,
1405                         req->rq_connect_cookie);
1406                 break;
1407         default:
1408                 /*
1409                  * We were unable to reply and will have to drop the
1410                  * request.  The server should reconnect and retransmit.
1411                  */
1412                 BUG_ON(task->tk_status == -EAGAIN);
1413                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1414                         "error: %d\n", task->tk_status);
1415                 break;
1416         }
1417         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1418 }
1419 #endif /* CONFIG_NFS_V4_1 */
1420
1421 /*
1422  * 6.   Sort out the RPC call status
1423  */
1424 static void
1425 call_status(struct rpc_task *task)
1426 {
1427         struct rpc_clnt *clnt = task->tk_client;
1428         struct rpc_rqst *req = task->tk_rqstp;
1429         int             status;
1430
1431         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1432                 task->tk_status = req->rq_reply_bytes_recvd;
1433
1434         dprint_status(task);
1435
1436         status = task->tk_status;
1437         if (status >= 0) {
1438                 task->tk_action = call_decode;
1439                 return;
1440         }
1441
1442         task->tk_status = 0;
1443         switch(status) {
1444         case -EHOSTDOWN:
1445         case -EHOSTUNREACH:
1446         case -ENETUNREACH:
1447                 /*
1448                  * Delay any retries for 3 seconds, then handle as if it
1449                  * were a timeout.
1450                  */
1451                 rpc_delay(task, 3*HZ);
1452         case -ETIMEDOUT:
1453                 task->tk_action = call_timeout;
1454                 if (task->tk_client->cl_discrtry)
1455                         xprt_conditional_disconnect(task->tk_xprt,
1456                                         req->rq_connect_cookie);
1457                 break;
1458         case -ECONNRESET:
1459         case -ECONNREFUSED:
1460                 rpc_force_rebind(clnt);
1461                 rpc_delay(task, 3*HZ);
1462         case -EPIPE:
1463         case -ENOTCONN:
1464                 task->tk_action = call_bind;
1465                 break;
1466         case -EAGAIN:
1467                 task->tk_action = call_transmit;
1468                 break;
1469         case -EIO:
1470                 /* shutdown or soft timeout */
1471                 rpc_exit(task, status);
1472                 break;
1473         default:
1474                 if (clnt->cl_chatty)
1475                         printk("%s: RPC call returned error %d\n",
1476                                clnt->cl_protname, -status);
1477                 rpc_exit(task, status);
1478         }
1479 }
1480
1481 /*
1482  * 6a.  Handle RPC timeout
1483  *      We do not release the request slot, so we keep using the
1484  *      same XID for all retransmits.
1485  */
1486 static void
1487 call_timeout(struct rpc_task *task)
1488 {
1489         struct rpc_clnt *clnt = task->tk_client;
1490
1491         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1492                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1493                 goto retry;
1494         }
1495
1496         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1497         task->tk_timeouts++;
1498
1499         if (RPC_IS_SOFTCONN(task)) {
1500                 rpc_exit(task, -ETIMEDOUT);
1501                 return;
1502         }
1503         if (RPC_IS_SOFT(task)) {
1504                 if (clnt->cl_chatty)
1505                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1506                                 clnt->cl_protname, clnt->cl_server);
1507                 rpc_exit(task, -EIO);
1508                 return;
1509         }
1510
1511         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1512                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1513                 if (clnt->cl_chatty)
1514                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1515                         clnt->cl_protname, clnt->cl_server);
1516         }
1517         rpc_force_rebind(clnt);
1518         /*
1519          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1520          * event? RFC2203 requires the server to drop all such requests.
1521          */
1522         rpcauth_invalcred(task);
1523
1524 retry:
1525         clnt->cl_stats->rpcretrans++;
1526         task->tk_action = call_bind;
1527         task->tk_status = 0;
1528 }
1529
1530 /*
1531  * 7.   Decode the RPC reply
1532  */
1533 static void
1534 call_decode(struct rpc_task *task)
1535 {
1536         struct rpc_clnt *clnt = task->tk_client;
1537         struct rpc_rqst *req = task->tk_rqstp;
1538         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1539         __be32          *p;
1540
1541         dprintk("RPC: %5u call_decode (status %d)\n",
1542                         task->tk_pid, task->tk_status);
1543
1544         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1545                 if (clnt->cl_chatty)
1546                         printk(KERN_NOTICE "%s: server %s OK\n",
1547                                 clnt->cl_protname, clnt->cl_server);
1548                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1549         }
1550
1551         /*
1552          * Ensure that we see all writes made by xprt_complete_rqst()
1553          * before it changed req->rq_reply_bytes_recvd.
1554          */
1555         smp_rmb();
1556         req->rq_rcv_buf.len = req->rq_private_buf.len;
1557
1558         /* Check that the softirq receive buffer is valid */
1559         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1560                                 sizeof(req->rq_rcv_buf)) != 0);
1561
1562         if (req->rq_rcv_buf.len < 12) {
1563                 if (!RPC_IS_SOFT(task)) {
1564                         task->tk_action = call_bind;
1565                         clnt->cl_stats->rpcretrans++;
1566                         goto out_retry;
1567                 }
1568                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1569                                 clnt->cl_protname, task->tk_status);
1570                 task->tk_action = call_timeout;
1571                 goto out_retry;
1572         }
1573
1574         p = rpc_verify_header(task);
1575         if (IS_ERR(p)) {
1576                 if (p == ERR_PTR(-EAGAIN))
1577                         goto out_retry;
1578                 return;
1579         }
1580
1581         task->tk_action = rpc_exit_task;
1582
1583         if (decode) {
1584                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1585                                                       task->tk_msg.rpc_resp);
1586         }
1587         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1588                         task->tk_status);
1589         return;
1590 out_retry:
1591         task->tk_status = 0;
1592         /* Note: rpc_verify_header() may have freed the RPC slot */
1593         if (task->tk_rqstp == req) {
1594                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
1595                 if (task->tk_client->cl_discrtry)
1596                         xprt_conditional_disconnect(task->tk_xprt,
1597                                         req->rq_connect_cookie);
1598         }
1599 }
1600
1601 static __be32 *
1602 rpc_encode_header(struct rpc_task *task)
1603 {
1604         struct rpc_clnt *clnt = task->tk_client;
1605         struct rpc_rqst *req = task->tk_rqstp;
1606         __be32          *p = req->rq_svec[0].iov_base;
1607
1608         /* FIXME: check buffer size? */
1609
1610         p = xprt_skip_transport_header(task->tk_xprt, p);
1611         *p++ = req->rq_xid;             /* XID */
1612         *p++ = htonl(RPC_CALL);         /* CALL */
1613         *p++ = htonl(RPC_VERSION);      /* RPC version */
1614         *p++ = htonl(clnt->cl_prog);    /* program number */
1615         *p++ = htonl(clnt->cl_vers);    /* program version */
1616         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1617         p = rpcauth_marshcred(task, p);
1618         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1619         return p;
1620 }
1621
1622 static __be32 *
1623 rpc_verify_header(struct rpc_task *task)
1624 {
1625         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1626         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1627         __be32  *p = iov->iov_base;
1628         u32 n;
1629         int error = -EACCES;
1630
1631         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1632                 /* RFC-1014 says that the representation of XDR data must be a
1633                  * multiple of four bytes
1634                  * - if it isn't pointer subtraction in the NFS client may give
1635                  *   undefined results
1636                  */
1637                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1638                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1639                        task->tk_rqstp->rq_rcv_buf.len);
1640                 goto out_eio;
1641         }
1642         if ((len -= 3) < 0)
1643                 goto out_overflow;
1644
1645         p += 1; /* skip XID */
1646         if ((n = ntohl(*p++)) != RPC_REPLY) {
1647                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1648                         task->tk_pid, __func__, n);
1649                 goto out_garbage;
1650         }
1651
1652         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1653                 if (--len < 0)
1654                         goto out_overflow;
1655                 switch ((n = ntohl(*p++))) {
1656                         case RPC_AUTH_ERROR:
1657                                 break;
1658                         case RPC_MISMATCH:
1659                                 dprintk("RPC: %5u %s: RPC call version "
1660                                                 "mismatch!\n",
1661                                                 task->tk_pid, __func__);
1662                                 error = -EPROTONOSUPPORT;
1663                                 goto out_err;
1664                         default:
1665                                 dprintk("RPC: %5u %s: RPC call rejected, "
1666                                                 "unknown error: %x\n",
1667                                                 task->tk_pid, __func__, n);
1668                                 goto out_eio;
1669                 }
1670                 if (--len < 0)
1671                         goto out_overflow;
1672                 switch ((n = ntohl(*p++))) {
1673                 case RPC_AUTH_REJECTEDCRED:
1674                 case RPC_AUTH_REJECTEDVERF:
1675                 case RPCSEC_GSS_CREDPROBLEM:
1676                 case RPCSEC_GSS_CTXPROBLEM:
1677                         if (!task->tk_cred_retry)
1678                                 break;
1679                         task->tk_cred_retry--;
1680                         dprintk("RPC: %5u %s: retry stale creds\n",
1681                                         task->tk_pid, __func__);
1682                         rpcauth_invalcred(task);
1683                         /* Ensure we obtain a new XID! */
1684                         xprt_release(task);
1685                         task->tk_action = call_reserve;
1686                         goto out_retry;
1687                 case RPC_AUTH_BADCRED:
1688                 case RPC_AUTH_BADVERF:
1689                         /* possibly garbled cred/verf? */
1690                         if (!task->tk_garb_retry)
1691                                 break;
1692                         task->tk_garb_retry--;
1693                         dprintk("RPC: %5u %s: retry garbled creds\n",
1694                                         task->tk_pid, __func__);
1695                         task->tk_action = call_bind;
1696                         goto out_retry;
1697                 case RPC_AUTH_TOOWEAK:
1698                         printk(KERN_NOTICE "RPC: server %s requires stronger "
1699                                "authentication.\n", task->tk_client->cl_server);
1700                         break;
1701                 default:
1702                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1703                                         task->tk_pid, __func__, n);
1704                         error = -EIO;
1705                 }
1706                 dprintk("RPC: %5u %s: call rejected %d\n",
1707                                 task->tk_pid, __func__, n);
1708                 goto out_err;
1709         }
1710         if (!(p = rpcauth_checkverf(task, p))) {
1711                 dprintk("RPC: %5u %s: auth check failed\n",
1712                                 task->tk_pid, __func__);
1713                 goto out_garbage;               /* bad verifier, retry */
1714         }
1715         len = p - (__be32 *)iov->iov_base - 1;
1716         if (len < 0)
1717                 goto out_overflow;
1718         switch ((n = ntohl(*p++))) {
1719         case RPC_SUCCESS:
1720                 return p;
1721         case RPC_PROG_UNAVAIL:
1722                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1723                                 task->tk_pid, __func__,
1724                                 (unsigned int)task->tk_client->cl_prog,
1725                                 task->tk_client->cl_server);
1726                 error = -EPFNOSUPPORT;
1727                 goto out_err;
1728         case RPC_PROG_MISMATCH:
1729                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1730                                 "server %s\n", task->tk_pid, __func__,
1731                                 (unsigned int)task->tk_client->cl_prog,
1732                                 (unsigned int)task->tk_client->cl_vers,
1733                                 task->tk_client->cl_server);
1734                 error = -EPROTONOSUPPORT;
1735                 goto out_err;
1736         case RPC_PROC_UNAVAIL:
1737                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1738                                 "version %u on server %s\n",
1739                                 task->tk_pid, __func__,
1740                                 rpc_proc_name(task),
1741                                 task->tk_client->cl_prog,
1742                                 task->tk_client->cl_vers,
1743                                 task->tk_client->cl_server);
1744                 error = -EOPNOTSUPP;
1745                 goto out_err;
1746         case RPC_GARBAGE_ARGS:
1747                 dprintk("RPC: %5u %s: server saw garbage\n",
1748                                 task->tk_pid, __func__);
1749                 break;                  /* retry */
1750         default:
1751                 dprintk("RPC: %5u %s: server accept status: %x\n",
1752                                 task->tk_pid, __func__, n);
1753                 /* Also retry */
1754         }
1755
1756 out_garbage:
1757         task->tk_client->cl_stats->rpcgarbage++;
1758         if (task->tk_garb_retry) {
1759                 task->tk_garb_retry--;
1760                 dprintk("RPC: %5u %s: retrying\n",
1761                                 task->tk_pid, __func__);
1762                 task->tk_action = call_bind;
1763 out_retry:
1764                 return ERR_PTR(-EAGAIN);
1765         }
1766 out_eio:
1767         error = -EIO;
1768 out_err:
1769         rpc_exit(task, error);
1770         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1771                         __func__, error);
1772         return ERR_PTR(error);
1773 out_overflow:
1774         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1775                         __func__);
1776         goto out_garbage;
1777 }
1778
1779 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1780 {
1781         return 0;
1782 }
1783
1784 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1785 {
1786         return 0;
1787 }
1788
1789 static struct rpc_procinfo rpcproc_null = {
1790         .p_encode = rpcproc_encode_null,
1791         .p_decode = rpcproc_decode_null,
1792 };
1793
1794 static int rpc_ping(struct rpc_clnt *clnt)
1795 {
1796         struct rpc_message msg = {
1797                 .rpc_proc = &rpcproc_null,
1798         };
1799         int err;
1800         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1801         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
1802         put_rpccred(msg.rpc_cred);
1803         return err;
1804 }
1805
1806 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1807 {
1808         struct rpc_message msg = {
1809                 .rpc_proc = &rpcproc_null,
1810                 .rpc_cred = cred,
1811         };
1812         struct rpc_task_setup task_setup_data = {
1813                 .rpc_client = clnt,
1814                 .rpc_message = &msg,
1815                 .callback_ops = &rpc_default_ops,
1816                 .flags = flags,
1817         };
1818         return rpc_run_task(&task_setup_data);
1819 }
1820 EXPORT_SYMBOL_GPL(rpc_call_null);
1821
1822 #ifdef RPC_DEBUG
1823 static void rpc_show_header(void)
1824 {
1825         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1826                 "-timeout ---ops--\n");
1827 }
1828
1829 static void rpc_show_task(const struct rpc_clnt *clnt,
1830                           const struct rpc_task *task)
1831 {
1832         const char *rpc_waitq = "none";
1833         char *p, action[KSYM_SYMBOL_LEN];
1834
1835         if (RPC_IS_QUEUED(task))
1836                 rpc_waitq = rpc_qname(task->tk_waitqueue);
1837
1838         /* map tk_action pointer to a function name; then trim off
1839          * the "+0x0 [sunrpc]" */
1840         sprint_symbol(action, (unsigned long)task->tk_action);
1841         p = strchr(action, '+');
1842         if (p)
1843                 *p = '\0';
1844
1845         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%s q:%s\n",
1846                 task->tk_pid, task->tk_flags, task->tk_status,
1847                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1848                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1849                 action, rpc_waitq);
1850 }
1851
1852 void rpc_show_tasks(void)
1853 {
1854         struct rpc_clnt *clnt;
1855         struct rpc_task *task;
1856         int header = 0;
1857
1858         spin_lock(&rpc_client_lock);
1859         list_for_each_entry(clnt, &all_clients, cl_clients) {
1860                 spin_lock(&clnt->cl_lock);
1861                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1862                         if (!header) {
1863                                 rpc_show_header();
1864                                 header++;
1865                         }
1866                         rpc_show_task(clnt, task);
1867                 }
1868                 spin_unlock(&clnt->cl_lock);
1869         }
1870         spin_unlock(&rpc_client_lock);
1871 }
1872 #endif