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/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                         if (RPC_IS_QUEUED(rovr))
 440                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 441                                                         rovr);
 442                 }
 443         }
 444         spin_unlock(&clnt->cl_lock);
 445 }
 446 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 447
 448 /*
 449  * Properly shut down an RPC client, terminating all outstanding
 450  * requests.
 451  */
 452 void rpc_shutdown_client(struct rpc_clnt *clnt)
 453 {
 454         dprintk("RPC:       shutting down %s client for %s\n",
 455                         clnt->cl_protname, clnt->cl_server);
 456
 457         while (!list_empty(&clnt->cl_tasks)) {
 458                 rpc_killall_tasks(clnt);
 459                 wait_event_timeout(destroy_wait,
 460                         list_empty(&clnt->cl_tasks), 1*HZ);
 461         }
 462
 463         rpc_release_client(clnt);
 464 }
 465 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 466
 467 /*
 468  * Free an RPC client
 469  */
 470 static void
 471 rpc_free_client(struct rpc_clnt *clnt)
 472 {
 473         dprintk("RPC:       destroying %s client for %s\n",
 474                         clnt->cl_protname, clnt->cl_server);
 475         if (!IS_ERR(clnt->cl_path.dentry)) {
 476                 rpc_remove_client_dir(clnt->cl_path.dentry);
 477                 rpc_put_mount();
 478         }
 479         if (clnt->cl_parent != clnt) {
 480                 rpc_release_client(clnt->cl_parent);
 481                 goto out_free;
 482         }
 483         if (clnt->cl_server != clnt->cl_inline_name)
 484                 kfree(clnt->cl_server);
 485 out_free:
 486         rpc_unregister_client(clnt);
 487         rpc_free_iostats(clnt->cl_metrics);
 488         kfree(clnt->cl_principal);
 489         clnt->cl_metrics = NULL;
 490         xprt_put(clnt->cl_xprt);
 491         rpciod_down();
 492         kfree(clnt);
 493 }
 494
 495 /*
 496  * Free an RPC client
 497  */
 498 static void
 499 rpc_free_auth(struct rpc_clnt *clnt)
 500 {
 501         if (clnt->cl_auth == NULL) {
 502                 rpc_free_client(clnt);
 503                 return;
 504         }
 505
 506         /*
 507          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 508          *       release remaining GSS contexts. This mechanism ensures
 509          *       that it can do so safely.
 510          */
 511         atomic_inc(&clnt->cl_count);
 512         rpcauth_release(clnt->cl_auth);
 513         clnt->cl_auth = NULL;
 514         if (atomic_dec_and_test(&clnt->cl_count))
 515                 rpc_free_client(clnt);
 516 }
 517
 518 /*
 519  * Release reference to the RPC client
 520  */
 521 void
 522 rpc_release_client(struct rpc_clnt *clnt)
 523 {
 524         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 525
 526         if (list_empty(&clnt->cl_tasks))
 527                 wake_up(&destroy_wait);
 528         if (atomic_dec_and_test(&clnt->cl_count))
 529                 rpc_free_auth(clnt);
 530 }
 531
 532 /**
 533  * rpc_bind_new_program - bind a new RPC program to an existing client
 534  * @old: old rpc_client
 535  * @program: rpc program to set
 536  * @vers: rpc program version
 537  *
 538  * Clones the rpc client and sets up a new RPC program. This is mainly
 539  * of use for enabling different RPC programs to share the same transport.
 540  * The Sun NFSv2/v3 ACL protocol can do this.
 541  */
 542 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 543                                       struct rpc_program *program,
 544                                       u32 vers)
 545 {
 546         struct rpc_clnt *clnt;
 547         struct rpc_version *version;
 548         int err;
 549
 550         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 551         version = program->version[vers];
 552         clnt = rpc_clone_client(old);
 553         if (IS_ERR(clnt))
 554                 goto out;
 555         clnt->cl_procinfo = version->procs;
 556         clnt->cl_maxproc  = version->nrprocs;
 557         clnt->cl_protname = program->name;
 558         clnt->cl_prog     = program->number;
 559         clnt->cl_vers     = version->number;
 560         clnt->cl_stats    = program->stats;
 561         err = rpc_ping(clnt);
 562         if (err != 0) {
 563                 rpc_shutdown_client(clnt);
 564                 clnt = ERR_PTR(err);
 565         }
 566 out:
 567         return clnt;
 568 }
 569 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 570
 571 void rpc_task_release_client(struct rpc_task *task)
 572 {
 573         struct rpc_clnt *clnt = task->tk_client;
 574
 575         if (clnt != NULL) {
 576                 /* Remove from client task list */
 577                 spin_lock(&clnt->cl_lock);
 578                 list_del(&task->tk_task);
 579                 spin_unlock(&clnt->cl_lock);
 580                 task->tk_client = NULL;
 581
 582                 rpc_release_client(clnt);
 583         }
 584 }
 585
 586 static
 587 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 588 {
 589         if (clnt != NULL) {
 590                 rpc_task_release_client(task);
 591                 task->tk_client = clnt;
 592                 atomic_inc(&clnt->cl_count);
 593                 if (clnt->cl_softrtry)
 594                         task->tk_flags |= RPC_TASK_SOFT;
 595                 /* Add to the client's list of all tasks */
 596                 spin_lock(&clnt->cl_lock);
 597                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 598                 spin_unlock(&clnt->cl_lock);
 599         }
 600 }
 601
 602 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 603 {
 604         rpc_task_release_client(task);
 605         rpc_task_set_client(task, clnt);
 606 }
 607 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 608
 609
 610 static void
 611 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 612 {
 613         if (msg != NULL) {
 614                 task->tk_msg.rpc_proc = msg->rpc_proc;
 615                 task->tk_msg.rpc_argp = msg->rpc_argp;
 616                 task->tk_msg.rpc_resp = msg->rpc_resp;
 617                 if (msg->rpc_cred != NULL)
 618                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 619         }
 620 }
 621
 622 /*
 623  * Default callback for async RPC calls
 624  */
 625 static void
 626 rpc_default_callback(struct rpc_task *task, void *data)
 627 {
 628 }
 629
 630 static const struct rpc_call_ops rpc_default_ops = {
 631         .rpc_call_done = rpc_default_callback,
 632 };
 633
 634 /**
 635  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 636  * @task_setup_data: pointer to task initialisation data
 637  */
 638 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 639 {
 640         struct rpc_task *task;
 641
 642         task = rpc_new_task(task_setup_data);
 643         if (IS_ERR(task))
 644                 goto out;
 645
 646         rpc_task_set_client(task, task_setup_data->rpc_client);
 647         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 648
 649         if (task->tk_action == NULL)
 650                 rpc_call_start(task);
 651
 652         atomic_inc(&task->tk_count);
 653         rpc_execute(task);
 654 out:
 655         return task;
 656 }
 657 EXPORT_SYMBOL_GPL(rpc_run_task);
 658
 659 /**
 660  * rpc_call_sync - Perform a synchronous RPC call
 661  * @clnt: pointer to RPC client
 662  * @msg: RPC call parameters
 663  * @flags: RPC call flags
 664  */
 665 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 666 {
 667         struct rpc_task *task;
 668         struct rpc_task_setup task_setup_data = {
 669                 .rpc_client = clnt,
 670                 .rpc_message = msg,
 671                 .callback_ops = &rpc_default_ops,
 672                 .flags = flags,
 673         };
 674         int status;
 675
 676         BUG_ON(flags & RPC_TASK_ASYNC);
 677
 678         task = rpc_run_task(&task_setup_data);
 679         if (IS_ERR(task))
 680                 return PTR_ERR(task);
 681         status = task->tk_status;
 682         rpc_put_task(task);
 683         return status;
 684 }
 685 EXPORT_SYMBOL_GPL(rpc_call_sync);
 686
 687 /**
 688  * rpc_call_async - Perform an asynchronous RPC call
 689  * @clnt: pointer to RPC client
 690  * @msg: RPC call parameters
 691  * @flags: RPC call flags
 692  * @tk_ops: RPC call ops
 693  * @data: user call data
 694  */
 695 int
 696 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 697                const struct rpc_call_ops *tk_ops, void *data)
 698 {
 699         struct rpc_task *task;
 700         struct rpc_task_setup task_setup_data = {
 701                 .rpc_client = clnt,
 702                 .rpc_message = msg,
 703                 .callback_ops = tk_ops,
 704                 .callback_data = data,
 705                 .flags = flags|RPC_TASK_ASYNC,
 706         };
 707
 708         task = rpc_run_task(&task_setup_data);
 709         if (IS_ERR(task))
 710                 return PTR_ERR(task);
 711         rpc_put_task(task);
 712         return 0;
 713 }
 714 EXPORT_SYMBOL_GPL(rpc_call_async);
 715
 716 #if defined(CONFIG_NFS_V4_1)
 717 /**
 718  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
 719  * rpc_execute against it
 720  * @req: RPC request
 721  * @tk_ops: RPC call ops
 722  */
 723 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
 724                                 const struct rpc_call_ops *tk_ops)
 725 {
 726         struct rpc_task *task;
 727         struct xdr_buf *xbufp = &req->rq_snd_buf;
 728         struct rpc_task_setup task_setup_data = {
 729                 .callback_ops = tk_ops,
 730         };
 731
 732         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
 733         /*
 734          * Create an rpc_task to send the data
 735          */
 736         task = rpc_new_task(&task_setup_data);
 737         if (IS_ERR(task)) {
 738                 xprt_free_bc_request(req);
 739                 goto out;
 740         }
 741         task->tk_rqstp = req;
 742
 743         /*
 744          * Set up the xdr_buf length.
 745          * This also indicates that the buffer is XDR encoded already.
 746          */
 747         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
 748                         xbufp->tail[0].iov_len;
 749
 750         task->tk_action = call_bc_transmit;
 751         atomic_inc(&task->tk_count);
 752         BUG_ON(atomic_read(&task->tk_count) != 2);
 753         rpc_execute(task);
 754
 755 out:
 756         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
 757         return task;
 758 }
 759 #endif /* CONFIG_NFS_V4_1 */
 760
 761 void
 762 rpc_call_start(struct rpc_task *task)
 763 {
 764         task->tk_action = call_start;
 765 }
 766 EXPORT_SYMBOL_GPL(rpc_call_start);
 767
 768 /**
 769  * rpc_peeraddr - extract remote peer address from clnt's xprt
 770  * @clnt: RPC client structure
 771  * @buf: target buffer
 772  * @bufsize: length of target buffer
 773  *
 774  * Returns the number of bytes that are actually in the stored address.
 775  */
 776 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 777 {
 778         size_t bytes;
 779         struct rpc_xprt *xprt = clnt->cl_xprt;
 780
 781         bytes = sizeof(xprt->addr);
 782         if (bytes > bufsize)
 783                 bytes = bufsize;
 784         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 785         return xprt->addrlen;
 786 }
 787 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 788
 789 /**
 790  * rpc_peeraddr2str - return remote peer address in printable format
 791  * @clnt: RPC client structure
 792  * @format: address format
 793  *
 794  */
 795 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
 796                              enum rpc_display_format_t format)
 797 {
 798         struct rpc_xprt *xprt = clnt->cl_xprt;
 799
 800         if (xprt->address_strings[format] != NULL)
 801                 return xprt->address_strings[format];
 802         else
 803                 return "unprintable";
 804 }
 805 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 806
 807 void
 808 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 809 {
 810         struct rpc_xprt *xprt = clnt->cl_xprt;
 811         if (xprt->ops->set_buffer_size)
 812                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 813 }
 814 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 815
 816 /*
 817  * Return size of largest payload RPC client can support, in bytes
 818  *
 819  * For stream transports, this is one RPC record fragment (see RFC
 820  * 1831), as we don't support multi-record requests yet.  For datagram
 821  * transports, this is the size of an IP packet minus the IP, UDP, and
 822  * RPC header sizes.
 823  */
 824 size_t rpc_max_payload(struct rpc_clnt *clnt)
 825 {
 826         return clnt->cl_xprt->max_payload;
 827 }
 828 EXPORT_SYMBOL_GPL(rpc_max_payload);
 829
 830 /**
 831  * rpc_force_rebind - force transport to check that remote port is unchanged
 832  * @clnt: client to rebind
 833  *
 834  */
 835 void rpc_force_rebind(struct rpc_clnt *clnt)
 836 {
 837         if (clnt->cl_autobind)
 838                 xprt_clear_bound(clnt->cl_xprt);
 839 }
 840 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 841
 842 /*
 843  * Restart an (async) RPC call from the call_prepare state.
 844  * Usually called from within the exit handler.
 845  */
 846 int
 847 rpc_restart_call_prepare(struct rpc_task *task)
 848 {
 849         if (RPC_ASSASSINATED(task))
 850                 return 0;
 851         task->tk_action = rpc_prepare_task;
 852         return 1;
 853 }
 854 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
 855
 856 /*
 857  * Restart an (async) RPC call. Usually called from within the
 858  * exit handler.
 859  */
 860 int
 861 rpc_restart_call(struct rpc_task *task)
 862 {
 863         if (RPC_ASSASSINATED(task))
 864                 return 0;
 865         task->tk_action = call_start;
 866         return 1;
 867 }
 868 EXPORT_SYMBOL_GPL(rpc_restart_call);
 869
 870 #ifdef RPC_DEBUG
 871 static const char *rpc_proc_name(const struct rpc_task *task)
 872 {
 873         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 874
 875         if (proc) {
 876                 if (proc->p_name)
 877                         return proc->p_name;
 878                 else
 879                         return "NULL";
 880         } else
 881                 return "no proc";
 882 }
 883 #endif
 884
 885 /*
 886  * 0.  Initial state
 887  *
 888  *     Other FSM states can be visited zero or more times, but
 889  *     this state is visited exactly once for each RPC.
 890  */
 891 static void
 892 call_start(struct rpc_task *task)
 893 {
 894         struct rpc_clnt *clnt = task->tk_client;
 895
 896         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
 897                         clnt->cl_protname, clnt->cl_vers,
 898                         rpc_proc_name(task),
 899                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 900
 901         /* Increment call count */
 902         task->tk_msg.rpc_proc->p_count++;
 903         clnt->cl_stats->rpccnt++;
 904         task->tk_action = call_reserve;
 905 }
 906
 907 /*
 908  * 1.   Reserve an RPC call slot
 909  */
 910 static void
 911 call_reserve(struct rpc_task *task)
 912 {
 913         dprint_status(task);
 914
 915         task->tk_status  = 0;
 916         task->tk_action  = call_reserveresult;
 917         xprt_reserve(task);
 918 }
 919
 920 /*
 921  * 1b.  Grok the result of xprt_reserve()
 922  */
 923 static void
 924 call_reserveresult(struct rpc_task *task)
 925 {
 926         int status = task->tk_status;
 927
 928         dprint_status(task);
 929
 930         /*
 931          * After a call to xprt_reserve(), we must have either
 932          * a request slot or else an error status.
 933          */
 934         task->tk_status = 0;
 935         if (status >= 0) {
 936                 if (task->tk_rqstp) {
 937                         task->tk_action = call_refresh;
 938                         return;
 939                 }
 940
 941                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 942                                 __func__, status);
 943                 rpc_exit(task, -EIO);
 944                 return;
 945         }
 946
 947         /*
 948          * Even though there was an error, we may have acquired
 949          * a request slot somehow.  Make sure not to leak it.
 950          */
 951         if (task->tk_rqstp) {
 952                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 953                                 __func__, status);
 954                 xprt_release(task);
 955         }
 956
 957         switch (status) {
 958         case -EAGAIN:   /* woken up; retry */
 959                 task->tk_action = call_reserve;
 960                 return;
 961         case -EIO:      /* probably a shutdown */
 962                 break;
 963         default:
 964                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 965                                 __func__, status);
 966                 break;
 967         }
 968         rpc_exit(task, status);
 969 }
 970
 971 /*
 972  * 2.   Bind and/or refresh the credentials
 973  */
 974 static void
 975 call_refresh(struct rpc_task *task)
 976 {
 977         dprint_status(task);
 978
 979         task->tk_action = call_refreshresult;
 980         task->tk_status = 0;
 981         task->tk_client->cl_stats->rpcauthrefresh++;
 982         rpcauth_refreshcred(task);
 983 }
 984
 985 /*
 986  * 2a.  Process the results of a credential refresh
 987  */
 988 static void
 989 call_refreshresult(struct rpc_task *task)
 990 {
 991         int status = task->tk_status;
 992
 993         dprint_status(task);
 994
 995         task->tk_status = 0;
 996         task->tk_action = call_refresh;
 997         switch (status) {
 998         case 0:
 999                 if (rpcauth_uptodatecred(task))
1000                         task->tk_action = call_allocate;
1001                 return;
1002         case -ETIMEDOUT:
1003                 rpc_delay(task, 3*HZ);
1004         case -EAGAIN:
1005                 status = -EACCES;
1006                 if (!task->tk_cred_retry)
1007                         break;
1008                 task->tk_cred_retry--;
1009                 dprintk("RPC: %5u %s: retry refresh creds\n",
1010                                 task->tk_pid, __func__);
1011                 return;
1012         }
1013         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1014                                 task->tk_pid, __func__, status);
1015         rpc_exit(task, status);
1016 }
1017
1018 /*
1019  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1020  *      (Note: buffer memory is freed in xprt_release).
1021  */
1022 static void
1023 call_allocate(struct rpc_task *task)
1024 {
1025         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1026         struct rpc_rqst *req = task->tk_rqstp;
1027         struct rpc_xprt *xprt = task->tk_xprt;
1028         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1029
1030         dprint_status(task);
1031
1032         task->tk_status = 0;
1033         task->tk_action = call_bind;
1034
1035         if (req->rq_buffer)
1036                 return;
1037
1038         if (proc->p_proc != 0) {
1039                 BUG_ON(proc->p_arglen == 0);
1040                 if (proc->p_decode != NULL)
1041                         BUG_ON(proc->p_replen == 0);
1042         }
1043
1044         /*
1045          * Calculate the size (in quads) of the RPC call
1046          * and reply headers, and convert both values
1047          * to byte sizes.
1048          */
1049         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1050         req->rq_callsize <<= 2;
1051         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1052         req->rq_rcvsize <<= 2;
1053
1054         req->rq_buffer = xprt->ops->buf_alloc(task,
1055                                         req->rq_callsize + req->rq_rcvsize);
1056         if (req->rq_buffer != NULL)
1057                 return;
1058
1059         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1060
1061         if (RPC_IS_ASYNC(task) || !signalled()) {
1062                 task->tk_action = call_allocate;
1063                 rpc_delay(task, HZ>>4);
1064                 return;
1065         }
1066
1067         rpc_exit(task, -ERESTARTSYS);
1068 }
1069
1070 static inline int
1071 rpc_task_need_encode(struct rpc_task *task)
1072 {
1073         return task->tk_rqstp->rq_snd_buf.len == 0;
1074 }
1075
1076 static inline void
1077 rpc_task_force_reencode(struct rpc_task *task)
1078 {
1079         task->tk_rqstp->rq_snd_buf.len = 0;
1080         task->tk_rqstp->rq_bytes_sent = 0;
1081 }
1082
1083 static inline void
1084 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1085 {
1086         buf->head[0].iov_base = start;
1087         buf->head[0].iov_len = len;
1088         buf->tail[0].iov_len = 0;
1089         buf->page_len = 0;
1090         buf->flags = 0;
1091         buf->len = 0;
1092         buf->buflen = len;
1093 }
1094
1095 /*
1096  * 3.   Encode arguments of an RPC call
1097  */
1098 static void
1099 rpc_xdr_encode(struct rpc_task *task)
1100 {
1101         struct rpc_rqst *req = task->tk_rqstp;
1102         kxdreproc_t     encode;
1103         __be32          *p;
1104
1105         dprint_status(task);
1106
1107         rpc_xdr_buf_init(&req->rq_snd_buf,
1108                          req->rq_buffer,
1109                          req->rq_callsize);
1110         rpc_xdr_buf_init(&req->rq_rcv_buf,
1111                          (char *)req->rq_buffer + req->rq_callsize,
1112                          req->rq_rcvsize);
1113
1114         p = rpc_encode_header(task);
1115         if (p == NULL) {
1116                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1117                 rpc_exit(task, -EIO);
1118                 return;
1119         }
1120
1121         encode = task->tk_msg.rpc_proc->p_encode;
1122         if (encode == NULL)
1123                 return;
1124
1125         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1126                         task->tk_msg.rpc_argp);
1127 }
1128
1129 /*
1130  * 4.   Get the server port number if not yet set
1131  */
1132 static void
1133 call_bind(struct rpc_task *task)
1134 {
1135         struct rpc_xprt *xprt = task->tk_xprt;
1136
1137         dprint_status(task);
1138
1139         task->tk_action = call_connect;
1140         if (!xprt_bound(xprt)) {
1141                 task->tk_action = call_bind_status;
1142                 task->tk_timeout = xprt->bind_timeout;
1143                 xprt->ops->rpcbind(task);
1144         }
1145 }
1146
1147 /*
1148  * 4a.  Sort out bind result
1149  */
1150 static void
1151 call_bind_status(struct rpc_task *task)
1152 {
1153         int status = -EIO;
1154
1155         if (task->tk_status >= 0) {
1156                 dprint_status(task);
1157                 task->tk_status = 0;
1158                 task->tk_action = call_connect;
1159                 return;
1160         }
1161
1162         switch (task->tk_status) {
1163         case -ENOMEM:
1164                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1165                 rpc_delay(task, HZ >> 2);
1166                 goto retry_timeout;
1167         case -EACCES:
1168                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1169                                 "unavailable\n", task->tk_pid);
1170                 /* fail immediately if this is an RPC ping */
1171                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1172                         status = -EOPNOTSUPP;
1173                         break;
1174                 }
1175                 rpc_delay(task, 3*HZ);
1176                 goto retry_timeout;
1177         case -ETIMEDOUT:
1178                 dprintk("RPC: %5u rpcbind request timed out\n",
1179                                 task->tk_pid);
1180                 goto retry_timeout;
1181         case -EPFNOSUPPORT:
1182                 /* server doesn't support any rpcbind version we know of */
1183                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1184                                 task->tk_pid);
1185                 break;
1186         case -EPROTONOSUPPORT:
1187                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1188                                 task->tk_pid);
1189                 task->tk_status = 0;
1190                 task->tk_action = call_bind;
1191                 return;
1192         case -ECONNREFUSED:             /* connection problems */
1193         case -ECONNRESET:
1194         case -ENOTCONN:
1195         case -EHOSTDOWN:
1196         case -EHOSTUNREACH:
1197         case -ENETUNREACH:
1198         case -EPIPE:
1199                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1200                                 task->tk_pid, task->tk_status);
1201                 if (!RPC_IS_SOFTCONN(task)) {
1202                         rpc_delay(task, 5*HZ);
1203                         goto retry_timeout;
1204                 }
1205                 status = task->tk_status;
1206                 break;
1207         default:
1208                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1209                                 task->tk_pid, -task->tk_status);
1210         }
1211
1212         rpc_exit(task, status);
1213         return;
1214
1215 retry_timeout:
1216         task->tk_action = call_timeout;
1217 }
1218
1219 /*
1220  * 4b.  Connect to the RPC server
1221  */
1222 static void
1223 call_connect(struct rpc_task *task)
1224 {
1225         struct rpc_xprt *xprt = task->tk_xprt;
1226
1227         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1228                         task->tk_pid, xprt,
1229                         (xprt_connected(xprt) ? "is" : "is not"));
1230
1231         task->tk_action = call_transmit;
1232         if (!xprt_connected(xprt)) {
1233                 task->tk_action = call_connect_status;
1234                 if (task->tk_status < 0)
1235                         return;
1236                 xprt_connect(task);
1237         }
1238 }
1239
1240 /*
1241  * 4c.  Sort out connect result
1242  */
1243 static void
1244 call_connect_status(struct rpc_task *task)
1245 {
1246         struct rpc_clnt *clnt = task->tk_client;
1247         int status = task->tk_status;
1248
1249         dprint_status(task);
1250
1251         task->tk_status = 0;
1252         if (status >= 0 || status == -EAGAIN) {
1253                 clnt->cl_stats->netreconn++;
1254                 task->tk_action = call_transmit;
1255                 return;
1256         }
1257
1258         switch (status) {
1259                 /* if soft mounted, test if we've timed out */
1260         case -ETIMEDOUT:
1261                 task->tk_action = call_timeout;
1262                 break;
1263         default:
1264                 rpc_exit(task, -EIO);
1265         }
1266 }
1267
1268 /*
1269  * 5.   Transmit the RPC request, and wait for reply
1270  */
1271 static void
1272 call_transmit(struct rpc_task *task)
1273 {
1274         dprint_status(task);
1275
1276         task->tk_action = call_status;
1277         if (task->tk_status < 0)
1278                 return;
1279         task->tk_status = xprt_prepare_transmit(task);
1280         if (task->tk_status != 0)
1281                 return;
1282         task->tk_action = call_transmit_status;
1283         /* Encode here so that rpcsec_gss can use correct sequence number. */
1284         if (rpc_task_need_encode(task)) {
1285                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1286                 rpc_xdr_encode(task);
1287                 /* Did the encode result in an error condition? */
1288                 if (task->tk_status != 0) {
1289                         /* Was the error nonfatal? */
1290                         if (task->tk_status == -EAGAIN)
1291                                 rpc_delay(task, HZ >> 4);
1292                         else
1293                                 rpc_exit(task, task->tk_status);
1294                         return;
1295                 }
1296         }
1297         xprt_transmit(task);
1298         if (task->tk_status < 0)
1299                 return;
1300         /*
1301          * On success, ensure that we call xprt_end_transmit() before sleeping
1302          * in order to allow access to the socket to other RPC requests.
1303          */
1304         call_transmit_status(task);
1305         if (rpc_reply_expected(task))
1306                 return;
1307         task->tk_action = rpc_exit_task;
1308         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1309 }
1310
1311 /*
1312  * 5a.  Handle cleanup after a transmission
1313  */
1314 static void
1315 call_transmit_status(struct rpc_task *task)
1316 {
1317         task->tk_action = call_status;
1318
1319         /*
1320          * Common case: success.  Force the compiler to put this
1321          * test first.
1322          */
1323         if (task->tk_status == 0) {
1324                 xprt_end_transmit(task);
1325                 rpc_task_force_reencode(task);
1326                 return;
1327         }
1328
1329         switch (task->tk_status) {
1330         case -EAGAIN:
1331                 break;
1332         default:
1333                 dprint_status(task);
1334                 xprt_end_transmit(task);
1335                 rpc_task_force_reencode(task);
1336                 break;
1337                 /*
1338                  * Special cases: if we've been waiting on the
1339                  * socket's write_space() callback, or if the
1340                  * socket just returned a connection error,
1341                  * then hold onto the transport lock.
1342                  */
1343         case -ECONNREFUSED:
1344         case -EHOSTDOWN:
1345         case -EHOSTUNREACH:
1346         case -ENETUNREACH:
1347                 if (RPC_IS_SOFTCONN(task)) {
1348                         xprt_end_transmit(task);
1349                         rpc_exit(task, task->tk_status);
1350                         break;
1351                 }
1352         case -ECONNRESET:
1353         case -ENOTCONN:
1354         case -EPIPE:
1355                 rpc_task_force_reencode(task);
1356         }
1357 }
1358
1359 #if defined(CONFIG_NFS_V4_1)
1360 /*
1361  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1362  * addition, disconnect on connectivity errors.
1363  */
1364 static void
1365 call_bc_transmit(struct rpc_task *task)
1366 {
1367         struct rpc_rqst *req = task->tk_rqstp;
1368
1369         BUG_ON(task->tk_status != 0);
1370         task->tk_status = xprt_prepare_transmit(task);
1371         if (task->tk_status == -EAGAIN) {
1372                 /*
1373                  * Could not reserve the transport. Try again after the
1374                  * transport is released.
1375                  */
1376                 task->tk_status = 0;
1377                 task->tk_action = call_bc_transmit;
1378                 return;
1379         }
1380
1381         task->tk_action = rpc_exit_task;
1382         if (task->tk_status < 0) {
1383                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1384                         "error: %d\n", task->tk_status);
1385                 return;
1386         }
1387
1388         xprt_transmit(task);
1389         xprt_end_transmit(task);
1390         dprint_status(task);
1391         switch (task->tk_status) {
1392         case 0:
1393                 /* Success */
1394                 break;
1395         case -EHOSTDOWN:
1396         case -EHOSTUNREACH:
1397         case -ENETUNREACH:
1398         case -ETIMEDOUT:
1399                 /*
1400                  * Problem reaching the server.  Disconnect and let the
1401                  * forechannel reestablish the connection.  The server will
1402                  * have to retransmit the backchannel request and we'll
1403                  * reprocess it.  Since these ops are idempotent, there's no
1404                  * need to cache our reply at this time.
1405                  */
1406                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1407                         "error: %d\n", task->tk_status);
1408                 xprt_conditional_disconnect(task->tk_xprt,
1409                         req->rq_connect_cookie);
1410                 break;
1411         default:
1412                 /*
1413                  * We were unable to reply and will have to drop the
1414                  * request.  The server should reconnect and retransmit.
1415                  */
1416                 BUG_ON(task->tk_status == -EAGAIN);
1417                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1418                         "error: %d\n", task->tk_status);
1419                 break;
1420         }
1421         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1422 }
1423 #endif /* CONFIG_NFS_V4_1 */
1424
1425 /*
1426  * 6.   Sort out the RPC call status
1427  */
1428 static void
1429 call_status(struct rpc_task *task)
1430 {
1431         struct rpc_clnt *clnt = task->tk_client;
1432         struct rpc_rqst *req = task->tk_rqstp;
1433         int             status;
1434
1435         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1436                 task->tk_status = req->rq_reply_bytes_recvd;
1437
1438         dprint_status(task);
1439
1440         status = task->tk_status;
1441         if (status >= 0) {
1442                 task->tk_action = call_decode;
1443                 return;
1444         }
1445
1446         task->tk_status = 0;
1447         switch(status) {
1448         case -EHOSTDOWN:
1449         case -EHOSTUNREACH:
1450         case -ENETUNREACH:
1451                 /*
1452                  * Delay any retries for 3 seconds, then handle as if it
1453                  * were a timeout.
1454                  */
1455                 rpc_delay(task, 3*HZ);
1456         case -ETIMEDOUT:
1457                 task->tk_action = call_timeout;
1458                 if (task->tk_client->cl_discrtry)
1459                         xprt_conditional_disconnect(task->tk_xprt,
1460                                         req->rq_connect_cookie);
1461                 break;
1462         case -ECONNRESET:
1463         case -ECONNREFUSED:
1464                 rpc_force_rebind(clnt);
1465                 rpc_delay(task, 3*HZ);
1466         case -EPIPE:
1467         case -ENOTCONN:
1468                 task->tk_action = call_bind;
1469                 break;
1470         case -EAGAIN:
1471                 task->tk_action = call_transmit;
1472                 break;
1473         case -EIO:
1474                 /* shutdown or soft timeout */
1475                 rpc_exit(task, status);
1476                 break;
1477         default:
1478                 if (clnt->cl_chatty)
1479                         printk("%s: RPC call returned error %d\n",
1480                                clnt->cl_protname, -status);
1481                 rpc_exit(task, status);
1482         }
1483 }
1484
1485 /*
1486  * 6a.  Handle RPC timeout
1487  *      We do not release the request slot, so we keep using the
1488  *      same XID for all retransmits.
1489  */
1490 static void
1491 call_timeout(struct rpc_task *task)
1492 {
1493         struct rpc_clnt *clnt = task->tk_client;
1494
1495         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1496                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1497                 goto retry;
1498         }
1499
1500         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1501         task->tk_timeouts++;
1502
1503         if (RPC_IS_SOFTCONN(task)) {
1504                 rpc_exit(task, -ETIMEDOUT);
1505                 return;
1506         }
1507         if (RPC_IS_SOFT(task)) {
1508                 if (clnt->cl_chatty)
1509                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1510                                 clnt->cl_protname, clnt->cl_server);
1511                 if (task->tk_flags & RPC_TASK_TIMEOUT)
1512                         rpc_exit(task, -ETIMEDOUT);
1513                 else
1514                         rpc_exit(task, -EIO);
1515                 return;
1516         }
1517
1518         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1519                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1520                 if (clnt->cl_chatty)
1521                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1522                         clnt->cl_protname, clnt->cl_server);
1523         }
1524         rpc_force_rebind(clnt);
1525         /*
1526          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1527          * event? RFC2203 requires the server to drop all such requests.
1528          */
1529         rpcauth_invalcred(task);
1530
1531 retry:
1532         clnt->cl_stats->rpcretrans++;
1533         task->tk_action = call_bind;
1534         task->tk_status = 0;
1535 }
1536
1537 /*
1538  * 7.   Decode the RPC reply
1539  */
1540 static void
1541 call_decode(struct rpc_task *task)
1542 {
1543         struct rpc_clnt *clnt = task->tk_client;
1544         struct rpc_rqst *req = task->tk_rqstp;
1545         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
1546         __be32          *p;
1547
1548         dprintk("RPC: %5u call_decode (status %d)\n",
1549                         task->tk_pid, task->tk_status);
1550
1551         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1552                 if (clnt->cl_chatty)
1553                         printk(KERN_NOTICE "%s: server %s OK\n",
1554                                 clnt->cl_protname, clnt->cl_server);
1555                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1556         }
1557
1558         /*
1559          * Ensure that we see all writes made by xprt_complete_rqst()
1560          * before it changed req->rq_reply_bytes_recvd.
1561          */
1562         smp_rmb();
1563         req->rq_rcv_buf.len = req->rq_private_buf.len;
1564
1565         /* Check that the softirq receive buffer is valid */
1566         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1567                                 sizeof(req->rq_rcv_buf)) != 0);
1568
1569         if (req->rq_rcv_buf.len < 12) {
1570                 if (!RPC_IS_SOFT(task)) {
1571                         task->tk_action = call_bind;
1572                         clnt->cl_stats->rpcretrans++;
1573                         goto out_retry;
1574                 }
1575                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1576                                 clnt->cl_protname, task->tk_status);
1577                 task->tk_action = call_timeout;
1578                 goto out_retry;
1579         }
1580
1581         p = rpc_verify_header(task);
1582         if (IS_ERR(p)) {
1583                 if (p == ERR_PTR(-EAGAIN))
1584                         goto out_retry;
1585                 return;
1586         }
1587
1588         task->tk_action = rpc_exit_task;
1589
1590         if (decode) {
1591                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1592                                                       task->tk_msg.rpc_resp);
1593         }
1594         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1595                         task->tk_status);
1596         return;
1597 out_retry:
1598         task->tk_status = 0;
1599         /* Note: rpc_verify_header() may have freed the RPC slot */
1600         if (task->tk_rqstp == req) {
1601                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
1602                 if (task->tk_client->cl_discrtry)
1603                         xprt_conditional_disconnect(task->tk_xprt,
1604                                         req->rq_connect_cookie);
1605         }
1606 }
1607
1608 static __be32 *
1609 rpc_encode_header(struct rpc_task *task)
1610 {
1611         struct rpc_clnt *clnt = task->tk_client;
1612         struct rpc_rqst *req = task->tk_rqstp;
1613         __be32          *p = req->rq_svec[0].iov_base;
1614
1615         /* FIXME: check buffer size? */
1616
1617         p = xprt_skip_transport_header(task->tk_xprt, p);
1618         *p++ = req->rq_xid;             /* XID */
1619         *p++ = htonl(RPC_CALL);         /* CALL */
1620         *p++ = htonl(RPC_VERSION);      /* RPC version */
1621         *p++ = htonl(clnt->cl_prog);    /* program number */
1622         *p++ = htonl(clnt->cl_vers);    /* program version */
1623         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1624         p = rpcauth_marshcred(task, p);
1625         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1626         return p;
1627 }
1628
1629 static __be32 *
1630 rpc_verify_header(struct rpc_task *task)
1631 {
1632         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1633         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1634         __be32  *p = iov->iov_base;
1635         u32 n;
1636         int error = -EACCES;
1637
1638         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1639                 /* RFC-1014 says that the representation of XDR data must be a
1640                  * multiple of four bytes
1641                  * - if it isn't pointer subtraction in the NFS client may give
1642                  *   undefined results
1643                  */
1644                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1645                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1646                        task->tk_rqstp->rq_rcv_buf.len);
1647                 goto out_eio;
1648         }
1649         if ((len -= 3) < 0)
1650                 goto out_overflow;
1651
1652         p += 1; /* skip XID */
1653         if ((n = ntohl(*p++)) != RPC_REPLY) {
1654                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1655                         task->tk_pid, __func__, n);
1656                 goto out_garbage;
1657         }
1658
1659         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1660                 if (--len < 0)
1661                         goto out_overflow;
1662                 switch ((n = ntohl(*p++))) {
1663                         case RPC_AUTH_ERROR:
1664                                 break;
1665                         case RPC_MISMATCH:
1666                                 dprintk("RPC: %5u %s: RPC call version "
1667                                                 "mismatch!\n",
1668                                                 task->tk_pid, __func__);
1669                                 error = -EPROTONOSUPPORT;
1670                                 goto out_err;
1671                         default:
1672                                 dprintk("RPC: %5u %s: RPC call rejected, "
1673                                                 "unknown error: %x\n",
1674                                                 task->tk_pid, __func__, n);
1675                                 goto out_eio;
1676                 }
1677                 if (--len < 0)
1678                         goto out_overflow;
1679                 switch ((n = ntohl(*p++))) {
1680                 case RPC_AUTH_REJECTEDCRED:
1681                 case RPC_AUTH_REJECTEDVERF:
1682                 case RPCSEC_GSS_CREDPROBLEM:
1683                 case RPCSEC_GSS_CTXPROBLEM:
1684                         if (!task->tk_cred_retry)
1685                                 break;
1686                         task->tk_cred_retry--;
1687                         dprintk("RPC: %5u %s: retry stale creds\n",
1688                                         task->tk_pid, __func__);
1689                         rpcauth_invalcred(task);
1690                         /* Ensure we obtain a new XID! */
1691                         xprt_release(task);
1692                         task->tk_action = call_reserve;
1693                         goto out_retry;
1694                 case RPC_AUTH_BADCRED:
1695                 case RPC_AUTH_BADVERF:
1696                         /* possibly garbled cred/verf? */
1697                         if (!task->tk_garb_retry)
1698                                 break;
1699                         task->tk_garb_retry--;
1700                         dprintk("RPC: %5u %s: retry garbled creds\n",
1701                                         task->tk_pid, __func__);
1702                         task->tk_action = call_bind;
1703                         goto out_retry;
1704                 case RPC_AUTH_TOOWEAK:
1705                         printk(KERN_NOTICE "RPC: server %s requires stronger "
1706                                "authentication.\n", task->tk_client->cl_server);
1707                         break;
1708                 default:
1709                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1710                                         task->tk_pid, __func__, n);
1711                         error = -EIO;
1712                 }
1713                 dprintk("RPC: %5u %s: call rejected %d\n",
1714                                 task->tk_pid, __func__, n);
1715                 goto out_err;
1716         }
1717         if (!(p = rpcauth_checkverf(task, p))) {
1718                 dprintk("RPC: %5u %s: auth check failed\n",
1719                                 task->tk_pid, __func__);
1720                 goto out_garbage;               /* bad verifier, retry */
1721         }
1722         len = p - (__be32 *)iov->iov_base - 1;
1723         if (len < 0)
1724                 goto out_overflow;
1725         switch ((n = ntohl(*p++))) {
1726         case RPC_SUCCESS:
1727                 return p;
1728         case RPC_PROG_UNAVAIL:
1729                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1730                                 task->tk_pid, __func__,
1731                                 (unsigned int)task->tk_client->cl_prog,
1732                                 task->tk_client->cl_server);
1733                 error = -EPFNOSUPPORT;
1734                 goto out_err;
1735         case RPC_PROG_MISMATCH:
1736                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1737                                 "server %s\n", task->tk_pid, __func__,
1738                                 (unsigned int)task->tk_client->cl_prog,
1739                                 (unsigned int)task->tk_client->cl_vers,
1740                                 task->tk_client->cl_server);
1741                 error = -EPROTONOSUPPORT;
1742                 goto out_err;
1743         case RPC_PROC_UNAVAIL:
1744                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1745                                 "version %u on server %s\n",
1746                                 task->tk_pid, __func__,
1747                                 rpc_proc_name(task),
1748                                 task->tk_client->cl_prog,
1749                                 task->tk_client->cl_vers,
1750                                 task->tk_client->cl_server);
1751                 error = -EOPNOTSUPP;
1752                 goto out_err;
1753         case RPC_GARBAGE_ARGS:
1754                 dprintk("RPC: %5u %s: server saw garbage\n",
1755                                 task->tk_pid, __func__);
1756                 break;                  /* retry */
1757         default:
1758                 dprintk("RPC: %5u %s: server accept status: %x\n",
1759                                 task->tk_pid, __func__, n);
1760                 /* Also retry */
1761         }
1762
1763 out_garbage:
1764         task->tk_client->cl_stats->rpcgarbage++;
1765         if (task->tk_garb_retry) {
1766                 task->tk_garb_retry--;
1767                 dprintk("RPC: %5u %s: retrying\n",
1768                                 task->tk_pid, __func__);
1769                 task->tk_action = call_bind;
1770 out_retry:
1771                 return ERR_PTR(-EAGAIN);
1772         }
1773 out_eio:
1774         error = -EIO;
1775 out_err:
1776         rpc_exit(task, error);
1777         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1778                         __func__, error);
1779         return ERR_PTR(error);
1780 out_overflow:
1781         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1782                         __func__);
1783         goto out_garbage;
1784 }
1785
1786 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1787 {
1788 }
1789
1790 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1791 {
1792         return 0;
1793 }
1794
1795 static struct rpc_procinfo rpcproc_null = {
1796         .p_encode = rpcproc_encode_null,
1797         .p_decode = rpcproc_decode_null,
1798 };
1799
1800 static int rpc_ping(struct rpc_clnt *clnt)
1801 {
1802         struct rpc_message msg = {
1803                 .rpc_proc = &rpcproc_null,
1804         };
1805         int err;
1806         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1807         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
1808         put_rpccred(msg.rpc_cred);
1809         return err;
1810 }
1811
1812 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1813 {
1814         struct rpc_message msg = {
1815                 .rpc_proc = &rpcproc_null,
1816                 .rpc_cred = cred,
1817         };
1818         struct rpc_task_setup task_setup_data = {
1819                 .rpc_client = clnt,
1820                 .rpc_message = &msg,
1821                 .callback_ops = &rpc_default_ops,
1822                 .flags = flags,
1823         };
1824         return rpc_run_task(&task_setup_data);
1825 }
1826 EXPORT_SYMBOL_GPL(rpc_call_null);
1827
1828 #ifdef RPC_DEBUG
1829 static void rpc_show_header(void)
1830 {
1831         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1832                 "-timeout ---ops--\n");
1833 }
1834
1835 static void rpc_show_task(const struct rpc_clnt *clnt,
1836                           const struct rpc_task *task)
1837 {
1838         const char *rpc_waitq = "none";
1839
1840         if (RPC_IS_QUEUED(task))
1841                 rpc_waitq = rpc_qname(task->tk_waitqueue);
1842
1843         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
1844                 task->tk_pid, task->tk_flags, task->tk_status,
1845                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1846                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1847                 task->tk_action, rpc_waitq);
1848 }
1849
1850 void rpc_show_tasks(void)
1851 {
1852         struct rpc_clnt *clnt;
1853         struct rpc_task *task;
1854         int header = 0;
1855
1856         spin_lock(&rpc_client_lock);
1857         list_for_each_entry(clnt, &all_clients, cl_clients) {
1858                 spin_lock(&clnt->cl_lock);
1859                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1860                         if (!header) {
1861                                 rpc_show_header();
1862                                 header++;
1863                         }
1864                         rpc_show_task(clnt, task);
1865                 }
1866                 spin_unlock(&clnt->cl_lock);
1867         }
1868         spin_unlock(&rpc_client_lock);
1869 }
1870 #endif