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  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  17  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  18  */
  19
  20 #include <asm/system.h>
  21
  22 #include <linux/module.h>
  23 #include <linux/types.h>
  24 #include <linux/kallsyms.h>
  25 #include <linux/mm.h>
  26 #include <linux/namei.h>
  27 #include <linux/mount.h>
  28 #include <linux/slab.h>
  29 #include <linux/utsname.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/in.h>
  32 #include <linux/in6.h>
  33 #include <linux/un.h>
  34
  35 #include <linux/sunrpc/clnt.h>
  36 #include <linux/sunrpc/rpc_pipe_fs.h>
  37 #include <linux/sunrpc/metrics.h>
  38 #include <linux/sunrpc/bc_xprt.h>
  39
  40 #include "sunrpc.h"
  41
  42 #ifdef RPC_DEBUG
  43 # define RPCDBG_FACILITY        RPCDBG_CALL
  44 #endif
  45
  46 #define dprint_status(t)                                        \
  47         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  48                         __func__, t->tk_status)
  49
  50 /*
  51  * All RPC clients are linked into this list
  52  */
  53 static LIST_HEAD(all_clients);
  54 static DEFINE_SPINLOCK(rpc_client_lock);
  55
  56 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  57
  58
  59 static void     call_start(struct rpc_task *task);
  60 static void     call_reserve(struct rpc_task *task);
  61 static void     call_reserveresult(struct rpc_task *task);
  62 static void     call_allocate(struct rpc_task *task);
  63 static void     call_decode(struct rpc_task *task);
  64 static void     call_bind(struct rpc_task *task);
  65 static void     call_bind_status(struct rpc_task *task);
  66 static void     call_transmit(struct rpc_task *task);
  67 #if defined(CONFIG_NFS_V4_1)
  68 static void     call_bc_transmit(struct rpc_task *task);
  69 #endif /* CONFIG_NFS_V4_1 */
  70 static void     call_status(struct rpc_task *task);
  71 static void     call_transmit_status(struct rpc_task *task);
  72 static void     call_refresh(struct rpc_task *task);
  73 static void     call_refreshresult(struct rpc_task *task);
  74 static void     call_timeout(struct rpc_task *task);
  75 static void     call_connect(struct rpc_task *task);
  76 static void     call_connect_status(struct rpc_task *task);
  77
  78 static __be32   *rpc_encode_header(struct rpc_task *task);
  79 static __be32   *rpc_verify_header(struct rpc_task *task);
  80 static int      rpc_ping(struct rpc_clnt *clnt);
  81
  82 static void rpc_register_client(struct rpc_clnt *clnt)
  83 {
  84         spin_lock(&rpc_client_lock);
  85         list_add(&clnt->cl_clients, &all_clients);
  86         spin_unlock(&rpc_client_lock);
  87 }
  88
  89 static void rpc_unregister_client(struct rpc_clnt *clnt)
  90 {
  91         spin_lock(&rpc_client_lock);
  92         list_del(&clnt->cl_clients);
  93         spin_unlock(&rpc_client_lock);
  94 }
  95
  96 static int
  97 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  98 {
  99         static uint32_t clntid;
 100         struct nameidata nd;
 101         struct path path;
 102         char name[15];
 103         struct qstr q = {
 104                 .name = name,
 105         };
 106         int error;
 107
 108         clnt->cl_path.mnt = ERR_PTR(-ENOENT);
 109         clnt->cl_path.dentry = ERR_PTR(-ENOENT);
 110         if (dir_name == NULL)
 111                 return 0;
 112
 113         path.mnt = rpc_get_mount();
 114         if (IS_ERR(path.mnt))
 115                 return PTR_ERR(path.mnt);
 116         error = vfs_path_lookup(path.mnt->mnt_root, path.mnt, dir_name, 0, &nd);
 117         if (error)
 118                 goto err;
 119
 120         for (;;) {
 121                 q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
 122                 name[sizeof(name) - 1] = '\0';
 123                 q.hash = full_name_hash(q.name, q.len);
 124                 path.dentry = rpc_create_client_dir(nd.path.dentry, &q, clnt);
 125                 if (!IS_ERR(path.dentry))
 126                         break;
 127                 error = PTR_ERR(path.dentry);
 128                 if (error != -EEXIST) {
 129                         printk(KERN_INFO "RPC: Couldn't create pipefs entry"
 130                                         " %s/%s, error %d\n",
 131                                         dir_name, name, error);
 132                         goto err_path_put;
 133                 }
 134         }
 135         path_put(&nd.path);
 136         clnt->cl_path = path;
 137         return 0;
 138 err_path_put:
 139         path_put(&nd.path);
 140 err:
 141         rpc_put_mount();
 142         return error;
 143 }
 144
 145 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
 146 {
 147         struct rpc_program      *program = args->program;
 148         struct rpc_version      *version;
 149         struct rpc_clnt         *clnt = NULL;
 150         struct rpc_auth         *auth;
 151         int err;
 152         size_t len;
 153
 154         /* sanity check the name before trying to print it */
 155         err = -EINVAL;
 156         len = strlen(args->servername);
 157         if (len > RPC_MAXNETNAMELEN)
 158                 goto out_no_rpciod;
 159         len++;
 160
 161         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 162                         program->name, args->servername, xprt);
 163
 164         err = rpciod_up();
 165         if (err)
 166                 goto out_no_rpciod;
 167         err = -EINVAL;
 168         if (!xprt)
 169                 goto out_no_xprt;
 170
 171         if (args->version >= program->nrvers)
 172                 goto out_err;
 173         version = program->version[args->version];
 174         if (version == NULL)
 175                 goto out_err;
 176
 177         err = -ENOMEM;
 178         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 179         if (!clnt)
 180                 goto out_err;
 181         clnt->cl_parent = clnt;
 182
 183         clnt->cl_server = clnt->cl_inline_name;
 184         if (len > sizeof(clnt->cl_inline_name)) {
 185                 char *buf = kmalloc(len, GFP_KERNEL);
 186                 if (buf != NULL)
 187                         clnt->cl_server = buf;
 188                 else
 189                         len = sizeof(clnt->cl_inline_name);
 190         }
 191         strlcpy(clnt->cl_server, args->servername, len);
 192
 193         clnt->cl_xprt     = xprt;
 194         clnt->cl_procinfo = version->procs;
 195         clnt->cl_maxproc  = version->nrprocs;
 196         clnt->cl_protname = program->name;
 197         clnt->cl_prog     = args->prognumber ? : program->number;
 198         clnt->cl_vers     = version->number;
 199         clnt->cl_stats    = program->stats;
 200         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 201         err = -ENOMEM;
 202         if (clnt->cl_metrics == NULL)
 203                 goto out_no_stats;
 204         clnt->cl_program  = program;
 205         INIT_LIST_HEAD(&clnt->cl_tasks);
 206         spin_lock_init(&clnt->cl_lock);
 207
 208         if (!xprt_bound(clnt->cl_xprt))
 209                 clnt->cl_autobind = 1;
 210
 211         clnt->cl_timeout = xprt->timeout;
 212         if (args->timeout != NULL) {
 213                 memcpy(&clnt->cl_timeout_default, args->timeout,
 214                                 sizeof(clnt->cl_timeout_default));
 215                 clnt->cl_timeout = &clnt->cl_timeout_default;
 216         }
 217
 218         clnt->cl_rtt = &clnt->cl_rtt_default;
 219         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 220         clnt->cl_principal = NULL;
 221         if (args->client_name) {
 222                 clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
 223                 if (!clnt->cl_principal)
 224                         goto out_no_principal;
 225         }
 226
 227         atomic_set(&clnt->cl_count, 1);
 228
 229         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 230         if (err < 0)
 231                 goto out_no_path;
 232
 233         auth = rpcauth_create(args->authflavor, clnt);
 234         if (IS_ERR(auth)) {
 235                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 236                                 args->authflavor);
 237                 err = PTR_ERR(auth);
 238                 goto out_no_auth;
 239         }
 240
 241         /* save the nodename */
 242         clnt->cl_nodelen = strlen(init_utsname()->nodename);
 243         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 244                 clnt->cl_nodelen = UNX_MAXNODENAME;
 245         memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen);
 246         rpc_register_client(clnt);
 247         return clnt;
 248
 249 out_no_auth:
 250         if (!IS_ERR(clnt->cl_path.dentry)) {
 251                 rpc_remove_client_dir(clnt->cl_path.dentry);
 252                 rpc_put_mount();
 253         }
 254 out_no_path:
 255         kfree(clnt->cl_principal);
 256 out_no_principal:
 257         rpc_free_iostats(clnt->cl_metrics);
 258 out_no_stats:
 259         if (clnt->cl_server != clnt->cl_inline_name)
 260                 kfree(clnt->cl_server);
 261         kfree(clnt);
 262 out_err:
 263         xprt_put(xprt);
 264 out_no_xprt:
 265         rpciod_down();
 266 out_no_rpciod:
 267         return ERR_PTR(err);
 268 }
 269
 270 /*
 271  * rpc_create - create an RPC client and transport with one call
 272  * @args: rpc_clnt create argument structure
 273  *
 274  * Creates and initializes an RPC transport and an RPC client.
 275  *
 276  * It can ping the server in order to determine if it is up, and to see if
 277  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 278  * this behavior so asynchronous tasks can also use rpc_create.
 279  */
 280 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 281 {
 282         struct rpc_xprt *xprt;
 283         struct rpc_clnt *clnt;
 284         struct xprt_create xprtargs = {
 285                 .net = args->net,
 286                 .ident = args->protocol,
 287                 .srcaddr = args->saddress,
 288                 .dstaddr = args->address,
 289                 .addrlen = args->addrsize,
 290                 .bc_xprt = args->bc_xprt,
 291         };
 292         char servername[48];
 293
 294         /*
 295          * If the caller chooses not to specify a hostname, whip
 296          * up a string representation of the passed-in address.
 297          */
 298         if (args->servername == NULL) {
 299                 struct sockaddr_un *sun =
 300                                 (struct sockaddr_un *)args->address;
 301                 struct sockaddr_in *sin =
 302                                 (struct sockaddr_in *)args->address;
 303                 struct sockaddr_in6 *sin6 =
 304                                 (struct sockaddr_in6 *)args->address;
 305
 306                 servername[0] = '\0';
 307                 switch (args->address->sa_family) {
 308                 case AF_LOCAL:
 309                         snprintf(servername, sizeof(servername), "%s",
 310                                  sun->sun_path);
 311                         break;
 312                 case AF_INET:
 313                         snprintf(servername, sizeof(servername), "%pI4",
 314                                  &sin->sin_addr.s_addr);
 315                         break;
 316                 case AF_INET6:
 317                         snprintf(servername, sizeof(servername), "%pI6",
 318                                  &sin6->sin6_addr);
 319                         break;
 320                 default:
 321                         /* caller wants default server name, but
 322                          * address family isn't recognized. */
 323                         return ERR_PTR(-EINVAL);
 324                 }
 325                 args->servername = servername;
 326         }
 327
 328         xprt = xprt_create_transport(&xprtargs);
 329         if (IS_ERR(xprt))
 330                 return (struct rpc_clnt *)xprt;
 331
 332         /*
 333          * By default, kernel RPC client connects from a reserved port.
 334          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 335          * but it is always enabled for rpciod, which handles the connect
 336          * operation.
 337          */
 338         xprt->resvport = 1;
 339         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 340                 xprt->resvport = 0;
 341
 342         clnt = rpc_new_client(args, xprt);
 343         if (IS_ERR(clnt))
 344                 return clnt;
 345
 346         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 347                 int err = rpc_ping(clnt);
 348                 if (err != 0) {
 349                         rpc_shutdown_client(clnt);
 350                         return ERR_PTR(err);
 351                 }
 352         }
 353
 354         clnt->cl_softrtry = 1;
 355         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 356                 clnt->cl_softrtry = 0;
 357
 358         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 359                 clnt->cl_autobind = 1;
 360         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 361                 clnt->cl_discrtry = 1;
 362         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 363                 clnt->cl_chatty = 1;
 364
 365         return clnt;
 366 }
 367 EXPORT_SYMBOL_GPL(rpc_create);
 368
 369 /*
 370  * This function clones the RPC client structure. It allows us to share the
 371  * same transport while varying parameters such as the authentication
 372  * flavour.
 373  */
 374 struct rpc_clnt *
 375 rpc_clone_client(struct rpc_clnt *clnt)
 376 {
 377         struct rpc_clnt *new;
 378         int err = -ENOMEM;
 379
 380         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 381         if (!new)
 382                 goto out_no_clnt;
 383         new->cl_parent = clnt;
 384         /* Turn off autobind on clones */
 385         new->cl_autobind = 0;
 386         INIT_LIST_HEAD(&new->cl_tasks);
 387         spin_lock_init(&new->cl_lock);
 388         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
 389         new->cl_metrics = rpc_alloc_iostats(clnt);
 390         if (new->cl_metrics == NULL)
 391                 goto out_no_stats;
 392         if (clnt->cl_principal) {
 393                 new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
 394                 if (new->cl_principal == NULL)
 395                         goto out_no_principal;
 396         }
 397         atomic_set(&new->cl_count, 1);
 398         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 399         if (err != 0)
 400                 goto out_no_path;
 401         if (new->cl_auth)
 402                 atomic_inc(&new->cl_auth->au_count);
 403         xprt_get(clnt->cl_xprt);
 404         atomic_inc(&clnt->cl_count);
 405         rpc_register_client(new);
 406         rpciod_up();
 407         return new;
 408 out_no_path:
 409         kfree(new->cl_principal);
 410 out_no_principal:
 411         rpc_free_iostats(new->cl_metrics);
 412 out_no_stats:
 413         kfree(new);
 414 out_no_clnt:
 415         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 416         return ERR_PTR(err);
 417 }
 418 EXPORT_SYMBOL_GPL(rpc_clone_client);
 419
 420 /*
 421  * Kill all tasks for the given client.
 422  * XXX: kill their descendants as well?
 423  */
 424 void rpc_killall_tasks(struct rpc_clnt *clnt)
 425 {
 426         struct rpc_task *rovr;
 427
 428
 429         if (list_empty(&clnt->cl_tasks))
 430                 return;
 431         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 432         /*
 433          * Spin lock all_tasks to prevent changes...
 434          */
 435         spin_lock(&clnt->cl_lock);
 436         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 437                 if (!RPC_IS_ACTIVATED(rovr))
 438                         continue;
 439                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 440                         rovr->tk_flags |= RPC_TASK_KILLED;
 441                         rpc_exit(rovr, -EIO);
 442                         if (RPC_IS_QUEUED(rovr))
 443                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 444                                                         rovr);
 445                 }
 446         }
 447         spin_unlock(&clnt->cl_lock);
 448 }
 449 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 450
 451 /*
 452  * Properly shut down an RPC client, terminating all outstanding
 453  * requests.
 454  */
 455 void rpc_shutdown_client(struct rpc_clnt *clnt)
 456 {
 457         dprintk("RPC:       shutting down %s client for %s\n",
 458                         clnt->cl_protname, clnt->cl_server);
 459
 460         while (!list_empty(&clnt->cl_tasks)) {
 461                 rpc_killall_tasks(clnt);
 462                 wait_event_timeout(destroy_wait,
 463                         list_empty(&clnt->cl_tasks), 1*HZ);
 464         }
 465
 466         rpc_release_client(clnt);
 467 }
 468 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 469
 470 /*
 471  * Free an RPC client
 472  */
 473 static void
 474 rpc_free_client(struct rpc_clnt *clnt)
 475 {
 476         dprintk("RPC:       destroying %s client for %s\n",
 477                         clnt->cl_protname, clnt->cl_server);
 478         if (!IS_ERR(clnt->cl_path.dentry)) {
 479                 rpc_remove_client_dir(clnt->cl_path.dentry);
 480                 rpc_put_mount();
 481         }
 482         if (clnt->cl_parent != clnt) {
 483                 rpc_release_client(clnt->cl_parent);
 484                 goto out_free;
 485         }
 486         if (clnt->cl_server != clnt->cl_inline_name)
 487                 kfree(clnt->cl_server);
 488 out_free:
 489         rpc_unregister_client(clnt);
 490         rpc_free_iostats(clnt->cl_metrics);
 491         kfree(clnt->cl_principal);
 492         clnt->cl_metrics = NULL;
 493         xprt_put(clnt->cl_xprt);
 494         rpciod_down();
 495         kfree(clnt);
 496 }
 497
 498 /*
 499  * Free an RPC client
 500  */
 501 static void
 502 rpc_free_auth(struct rpc_clnt *clnt)
 503 {
 504         if (clnt->cl_auth == NULL) {
 505                 rpc_free_client(clnt);
 506                 return;
 507         }
 508
 509         /*
 510          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 511          *       release remaining GSS contexts. This mechanism ensures
 512          *       that it can do so safely.
 513          */
 514         atomic_inc(&clnt->cl_count);
 515         rpcauth_release(clnt->cl_auth);
 516         clnt->cl_auth = NULL;
 517         if (atomic_dec_and_test(&clnt->cl_count))
 518                 rpc_free_client(clnt);
 519 }
 520
 521 /*
 522  * Release reference to the RPC client
 523  */
 524 void
 525 rpc_release_client(struct rpc_clnt *clnt)
 526 {
 527         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 528
 529         if (list_empty(&clnt->cl_tasks))
 530                 wake_up(&destroy_wait);
 531         if (atomic_dec_and_test(&clnt->cl_count))
 532                 rpc_free_auth(clnt);
 533 }
 534
 535 /**
 536  * rpc_bind_new_program - bind a new RPC program to an existing client
 537  * @old: old rpc_client
 538  * @program: rpc program to set
 539  * @vers: rpc program version
 540  *
 541  * Clones the rpc client and sets up a new RPC program. This is mainly
 542  * of use for enabling different RPC programs to share the same transport.
 543  * The Sun NFSv2/v3 ACL protocol can do this.
 544  */
 545 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 546                                       struct rpc_program *program,
 547                                       u32 vers)
 548 {
 549         struct rpc_clnt *clnt;
 550         struct rpc_version *version;
 551         int err;
 552
 553         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 554         version = program->version[vers];
 555         clnt = rpc_clone_client(old);
 556         if (IS_ERR(clnt))
 557                 goto out;
 558         clnt->cl_procinfo = version->procs;
 559         clnt->cl_maxproc  = version->nrprocs;
 560         clnt->cl_protname = program->name;
 561         clnt->cl_prog     = program->number;
 562         clnt->cl_vers     = version->number;
 563         clnt->cl_stats    = program->stats;
 564         err = rpc_ping(clnt);
 565         if (err != 0) {
 566                 rpc_shutdown_client(clnt);
 567                 clnt = ERR_PTR(err);
 568         }
 569 out:
 570         return clnt;
 571 }
 572 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 573
 574 void rpc_task_release_client(struct rpc_task *task)
 575 {
 576         struct rpc_clnt *clnt = task->tk_client;
 577
 578         if (clnt != NULL) {
 579                 /* Remove from client task list */
 580                 spin_lock(&clnt->cl_lock);
 581                 list_del(&task->tk_task);
 582                 spin_unlock(&clnt->cl_lock);
 583                 task->tk_client = NULL;
 584
 585                 rpc_release_client(clnt);
 586         }
 587 }
 588
 589 static
 590 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 591 {
 592         if (clnt != NULL) {
 593                 rpc_task_release_client(task);
 594                 task->tk_client = clnt;
 595                 atomic_inc(&clnt->cl_count);
 596                 if (clnt->cl_softrtry)
 597                         task->tk_flags |= RPC_TASK_SOFT;
 598                 /* Add to the client's list of all tasks */
 599                 spin_lock(&clnt->cl_lock);
 600                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 601                 spin_unlock(&clnt->cl_lock);
 602         }
 603 }
 604
 605 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 606 {
 607         rpc_task_release_client(task);
 608         rpc_task_set_client(task, clnt);
 609 }
 610 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 611
 612
 613 static void
 614 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 615 {
 616         if (msg != NULL) {
 617                 task->tk_msg.rpc_proc = msg->rpc_proc;
 618                 task->tk_msg.rpc_argp = msg->rpc_argp;
 619                 task->tk_msg.rpc_resp = msg->rpc_resp;
 620                 if (msg->rpc_cred != NULL)
 621                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 622         }
 623 }
 624
 625 /*
 626  * Default callback for async RPC calls
 627  */
 628 static void
 629 rpc_default_callback(struct rpc_task *task, void *data)
 630 {
 631 }
 632
 633 static const struct rpc_call_ops rpc_default_ops = {
 634         .rpc_call_done = rpc_default_callback,
 635 };
 636
 637 /**
 638  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 639  * @task_setup_data: pointer to task initialisation data
 640  */
 641 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 642 {
 643         struct rpc_task *task;
 644
 645         task = rpc_new_task(task_setup_data);
 646         if (IS_ERR(task))
 647                 goto out;
 648
 649         rpc_task_set_client(task, task_setup_data->rpc_client);
 650         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 651
 652         if (task->tk_action == NULL)
 653                 rpc_call_start(task);
 654
 655         atomic_inc(&task->tk_count);
 656         rpc_execute(task);
 657 out:
 658         return task;
 659 }
 660 EXPORT_SYMBOL_GPL(rpc_run_task);
 661
 662 /**
 663  * rpc_call_sync - Perform a synchronous RPC call
 664  * @clnt: pointer to RPC client
 665  * @msg: RPC call parameters
 666  * @flags: RPC call flags
 667  */
 668 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 669 {
 670         struct rpc_task *task;
 671         struct rpc_task_setup task_setup_data = {
 672                 .rpc_client = clnt,
 673                 .rpc_message = msg,
 674                 .callback_ops = &rpc_default_ops,
 675                 .flags = flags,
 676         };
 677         int status;
 678
 679         BUG_ON(flags & RPC_TASK_ASYNC);
 680
 681         task = rpc_run_task(&task_setup_data);
 682         if (IS_ERR(task))
 683                 return PTR_ERR(task);
 684         status = task->tk_status;
 685         rpc_put_task(task);
 686         return status;
 687 }
 688 EXPORT_SYMBOL_GPL(rpc_call_sync);
 689
 690 /**
 691  * rpc_call_async - Perform an asynchronous RPC call
 692  * @clnt: pointer to RPC client
 693  * @msg: RPC call parameters
 694  * @flags: RPC call flags
 695  * @tk_ops: RPC call ops
 696  * @data: user call data
 697  */
 698 int
 699 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 700                const struct rpc_call_ops *tk_ops, void *data)
 701 {
 702         struct rpc_task *task;
 703         struct rpc_task_setup task_setup_data = {
 704                 .rpc_client = clnt,
 705                 .rpc_message = msg,
 706                 .callback_ops = tk_ops,
 707                 .callback_data = data,
 708                 .flags = flags|RPC_TASK_ASYNC,
 709         };
 710
 711         task = rpc_run_task(&task_setup_data);
 712         if (IS_ERR(task))
 713                 return PTR_ERR(task);
 714         rpc_put_task(task);
 715         return 0;
 716 }
 717 EXPORT_SYMBOL_GPL(rpc_call_async);
 718
 719 #if defined(CONFIG_NFS_V4_1)
 720 /**
 721  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
 722  * rpc_execute against it
 723  * @req: RPC request
 724  * @tk_ops: RPC call ops
 725  */
 726 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
 727                                 const struct rpc_call_ops *tk_ops)
 728 {
 729         struct rpc_task *task;
 730         struct xdr_buf *xbufp = &req->rq_snd_buf;
 731         struct rpc_task_setup task_setup_data = {
 732                 .callback_ops = tk_ops,
 733         };
 734
 735         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
 736         /*
 737          * Create an rpc_task to send the data
 738          */
 739         task = rpc_new_task(&task_setup_data);
 740         if (IS_ERR(task)) {
 741                 xprt_free_bc_request(req);
 742                 goto out;
 743         }
 744         task->tk_rqstp = req;
 745
 746         /*
 747          * Set up the xdr_buf length.
 748          * This also indicates that the buffer is XDR encoded already.
 749          */
 750         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
 751                         xbufp->tail[0].iov_len;
 752
 753         task->tk_action = call_bc_transmit;
 754         atomic_inc(&task->tk_count);
 755         BUG_ON(atomic_read(&task->tk_count) != 2);
 756         rpc_execute(task);
 757
 758 out:
 759         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
 760         return task;
 761 }
 762 #endif /* CONFIG_NFS_V4_1 */
 763
 764 void
 765 rpc_call_start(struct rpc_task *task)
 766 {
 767         task->tk_action = call_start;
 768 }
 769 EXPORT_SYMBOL_GPL(rpc_call_start);
 770
 771 /**
 772  * rpc_peeraddr - extract remote peer address from clnt's xprt
 773  * @clnt: RPC client structure
 774  * @buf: target buffer
 775  * @bufsize: length of target buffer
 776  *
 777  * Returns the number of bytes that are actually in the stored address.
 778  */
 779 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 780 {
 781         size_t bytes;
 782         struct rpc_xprt *xprt = clnt->cl_xprt;
 783
 784         bytes = sizeof(xprt->addr);
 785         if (bytes > bufsize)
 786                 bytes = bufsize;
 787         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 788         return xprt->addrlen;
 789 }
 790 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 791
 792 /**
 793  * rpc_peeraddr2str - return remote peer address in printable format
 794  * @clnt: RPC client structure
 795  * @format: address format
 796  *
 797  */
 798 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
 799                              enum rpc_display_format_t format)
 800 {
 801         struct rpc_xprt *xprt = clnt->cl_xprt;
 802
 803         if (xprt->address_strings[format] != NULL)
 804                 return xprt->address_strings[format];
 805         else
 806                 return "unprintable";
 807 }
 808 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 809
 810 void
 811 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 812 {
 813         struct rpc_xprt *xprt = clnt->cl_xprt;
 814         if (xprt->ops->set_buffer_size)
 815                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 816 }
 817 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 818
 819 /*
 820  * Return size of largest payload RPC client can support, in bytes
 821  *
 822  * For stream transports, this is one RPC record fragment (see RFC
 823  * 1831), as we don't support multi-record requests yet.  For datagram
 824  * transports, this is the size of an IP packet minus the IP, UDP, and
 825  * RPC header sizes.
 826  */
 827 size_t rpc_max_payload(struct rpc_clnt *clnt)
 828 {
 829         return clnt->cl_xprt->max_payload;
 830 }
 831 EXPORT_SYMBOL_GPL(rpc_max_payload);
 832
 833 /**
 834  * rpc_force_rebind - force transport to check that remote port is unchanged
 835  * @clnt: client to rebind
 836  *
 837  */
 838 void rpc_force_rebind(struct rpc_clnt *clnt)
 839 {
 840         if (clnt->cl_autobind)
 841                 xprt_clear_bound(clnt->cl_xprt);
 842 }
 843 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 844
 845 /*
 846  * Restart an (async) RPC call from the call_prepare state.
 847  * Usually called from within the exit handler.
 848  */
 849 int
 850 rpc_restart_call_prepare(struct rpc_task *task)
 851 {
 852         if (RPC_ASSASSINATED(task))
 853                 return 0;
 854         task->tk_action = rpc_prepare_task;
 855         return 1;
 856 }
 857 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
 858
 859 /*
 860  * Restart an (async) RPC call. Usually called from within the
 861  * exit handler.
 862  */
 863 int
 864 rpc_restart_call(struct rpc_task *task)
 865 {
 866         if (RPC_ASSASSINATED(task))
 867                 return 0;
 868         task->tk_action = call_start;
 869         return 1;
 870 }
 871 EXPORT_SYMBOL_GPL(rpc_restart_call);
 872
 873 #ifdef RPC_DEBUG
 874 static const char *rpc_proc_name(const struct rpc_task *task)
 875 {
 876         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 877
 878         if (proc) {
 879                 if (proc->p_name)
 880                         return proc->p_name;
 881                 else
 882                         return "NULL";
 883         } else
 884                 return "no proc";
 885 }
 886 #endif
 887
 888 /*
 889  * 0.  Initial state
 890  *
 891  *     Other FSM states can be visited zero or more times, but
 892  *     this state is visited exactly once for each RPC.
 893  */
 894 static void
 895 call_start(struct rpc_task *task)
 896 {
 897         struct rpc_clnt *clnt = task->tk_client;
 898
 899         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
 900                         clnt->cl_protname, clnt->cl_vers,
 901                         rpc_proc_name(task),
 902                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 903
 904         /* Increment call count */
 905         task->tk_msg.rpc_proc->p_count++;
 906         clnt->cl_stats->rpccnt++;
 907         task->tk_action = call_reserve;
 908 }
 909
 910 /*
 911  * 1.   Reserve an RPC call slot
 912  */
 913 static void
 914 call_reserve(struct rpc_task *task)
 915 {
 916         dprint_status(task);
 917
 918         task->tk_status  = 0;
 919         task->tk_action  = call_reserveresult;
 920         xprt_reserve(task);
 921 }
 922
 923 /*
 924  * 1b.  Grok the result of xprt_reserve()
 925  */
 926 static void
 927 call_reserveresult(struct rpc_task *task)
 928 {
 929         int status = task->tk_status;
 930
 931         dprint_status(task);
 932
 933         /*
 934          * After a call to xprt_reserve(), we must have either
 935          * a request slot or else an error status.
 936          */
 937         task->tk_status = 0;
 938         if (status >= 0) {
 939                 if (task->tk_rqstp) {
 940                         task->tk_action = call_refresh;
 941                         return;
 942                 }
 943
 944                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 945                                 __func__, status);
 946                 rpc_exit(task, -EIO);
 947                 return;
 948         }
 949
 950         /*
 951          * Even though there was an error, we may have acquired
 952          * a request slot somehow.  Make sure not to leak it.
 953          */
 954         if (task->tk_rqstp) {
 955                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 956                                 __func__, status);
 957                 xprt_release(task);
 958         }
 959
 960         switch (status) {
 961         case -EAGAIN:   /* woken up; retry */
 962                 task->tk_action = call_reserve;
 963                 return;
 964         case -EIO:      /* probably a shutdown */
 965                 break;
 966         default:
 967                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 968                                 __func__, status);
 969                 break;
 970         }
 971         rpc_exit(task, status);
 972 }
 973
 974 /*
 975  * 2.   Bind and/or refresh the credentials
 976  */
 977 static void
 978 call_refresh(struct rpc_task *task)
 979 {
 980         dprint_status(task);
 981
 982         task->tk_action = call_refreshresult;
 983         task->tk_status = 0;
 984         task->tk_client->cl_stats->rpcauthrefresh++;
 985         rpcauth_refreshcred(task);
 986 }
 987
 988 /*
 989  * 2a.  Process the results of a credential refresh
 990  */
 991 static void
 992 call_refreshresult(struct rpc_task *task)
 993 {
 994         int status = task->tk_status;
 995
 996         dprint_status(task);
 997
 998         task->tk_status = 0;
 999         task->tk_action = call_refresh;
1000         switch (status) {
1001         case 0:
1002                 if (rpcauth_uptodatecred(task))
1003                         task->tk_action = call_allocate;
1004                 return;
1005         case -ETIMEDOUT:
1006                 rpc_delay(task, 3*HZ);
1007         case -EAGAIN:
1008                 status = -EACCES;
1009                 if (!task->tk_cred_retry)
1010                         break;
1011                 task->tk_cred_retry--;
1012                 dprintk("RPC: %5u %s: retry refresh creds\n",
1013                                 task->tk_pid, __func__);
1014                 return;
1015         }
1016         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1017                                 task->tk_pid, __func__, status);
1018         rpc_exit(task, status);
1019 }
1020
1021 /*
1022  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1023  *      (Note: buffer memory is freed in xprt_release).
1024  */
1025 static void
1026 call_allocate(struct rpc_task *task)
1027 {
1028         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1029         struct rpc_rqst *req = task->tk_rqstp;
1030         struct rpc_xprt *xprt = task->tk_xprt;
1031         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1032
1033         dprint_status(task);
1034
1035         task->tk_status = 0;
1036         task->tk_action = call_bind;
1037
1038         if (req->rq_buffer)
1039                 return;
1040
1041         if (proc->p_proc != 0) {
1042                 BUG_ON(proc->p_arglen == 0);
1043                 if (proc->p_decode != NULL)
1044                         BUG_ON(proc->p_replen == 0);
1045         }
1046
1047         /*
1048          * Calculate the size (in quads) of the RPC call
1049          * and reply headers, and convert both values
1050          * to byte sizes.
1051          */
1052         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1053         req->rq_callsize <<= 2;
1054         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1055         req->rq_rcvsize <<= 2;
1056
1057         req->rq_buffer = xprt->ops->buf_alloc(task,
1058                                         req->rq_callsize + req->rq_rcvsize);
1059         if (req->rq_buffer != NULL)
1060                 return;
1061
1062         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1063
1064         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1065                 task->tk_action = call_allocate;
1066                 rpc_delay(task, HZ>>4);
1067                 return;
1068         }
1069
1070         rpc_exit(task, -ERESTARTSYS);
1071 }
1072
1073 static inline int
1074 rpc_task_need_encode(struct rpc_task *task)
1075 {
1076         return task->tk_rqstp->rq_snd_buf.len == 0;
1077 }
1078
1079 static inline void
1080 rpc_task_force_reencode(struct rpc_task *task)
1081 {
1082         task->tk_rqstp->rq_snd_buf.len = 0;
1083         task->tk_rqstp->rq_bytes_sent = 0;
1084 }
1085
1086 static inline void
1087 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1088 {
1089         buf->head[0].iov_base = start;
1090         buf->head[0].iov_len = len;
1091         buf->tail[0].iov_len = 0;
1092         buf->page_len = 0;
1093         buf->flags = 0;
1094         buf->len = 0;
1095         buf->buflen = len;
1096 }
1097
1098 /*
1099  * 3.   Encode arguments of an RPC call
1100  */
1101 static void
1102 rpc_xdr_encode(struct rpc_task *task)
1103 {
1104         struct rpc_rqst *req = task->tk_rqstp;
1105         kxdreproc_t     encode;
1106         __be32          *p;
1107
1108         dprint_status(task);
1109
1110         rpc_xdr_buf_init(&req->rq_snd_buf,
1111                          req->rq_buffer,
1112                          req->rq_callsize);
1113         rpc_xdr_buf_init(&req->rq_rcv_buf,
1114                          (char *)req->rq_buffer + req->rq_callsize,
1115                          req->rq_rcvsize);
1116
1117         p = rpc_encode_header(task);
1118         if (p == NULL) {
1119                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1120                 rpc_exit(task, -EIO);
1121                 return;
1122         }
1123
1124         encode = task->tk_msg.rpc_proc->p_encode;
1125         if (encode == NULL)
1126                 return;
1127
1128         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1129                         task->tk_msg.rpc_argp);
1130 }
1131
1132 /*
1133  * 4.   Get the server port number if not yet set
1134  */
1135 static void
1136 call_bind(struct rpc_task *task)
1137 {
1138         struct rpc_xprt *xprt = task->tk_xprt;
1139
1140         dprint_status(task);
1141
1142         task->tk_action = call_connect;
1143         if (!xprt_bound(xprt)) {
1144                 task->tk_action = call_bind_status;
1145                 task->tk_timeout = xprt->bind_timeout;
1146                 xprt->ops->rpcbind(task);
1147         }
1148 }
1149
1150 /*
1151  * 4a.  Sort out bind result
1152  */
1153 static void
1154 call_bind_status(struct rpc_task *task)
1155 {
1156         int status = -EIO;
1157
1158         if (task->tk_status >= 0) {
1159                 dprint_status(task);
1160                 task->tk_status = 0;
1161                 task->tk_action = call_connect;
1162                 return;
1163         }
1164
1165         switch (task->tk_status) {
1166         case -ENOMEM:
1167                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1168                 rpc_delay(task, HZ >> 2);
1169                 goto retry_timeout;
1170         case -EACCES:
1171                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1172                                 "unavailable\n", task->tk_pid);
1173                 /* fail immediately if this is an RPC ping */
1174                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1175                         status = -EOPNOTSUPP;
1176                         break;
1177                 }
1178                 if (task->tk_rebind_retry == 0)
1179                         break;
1180                 task->tk_rebind_retry--;
1181                 rpc_delay(task, 3*HZ);
1182                 goto retry_timeout;
1183         case -ETIMEDOUT:
1184                 dprintk("RPC: %5u rpcbind request timed out\n",
1185                                 task->tk_pid);
1186                 goto retry_timeout;
1187         case -EPFNOSUPPORT:
1188                 /* server doesn't support any rpcbind version we know of */
1189                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1190                                 task->tk_pid);
1191                 break;
1192         case -EPROTONOSUPPORT:
1193                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1194                                 task->tk_pid);
1195                 task->tk_status = 0;
1196                 task->tk_action = call_bind;
1197                 return;
1198         case -ECONNREFUSED:             /* connection problems */
1199         case -ECONNRESET:
1200         case -ENOTCONN:
1201         case -EHOSTDOWN:
1202         case -EHOSTUNREACH:
1203         case -ENETUNREACH:
1204         case -EPIPE:
1205                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1206                                 task->tk_pid, task->tk_status);
1207                 if (!RPC_IS_SOFTCONN(task)) {
1208                         rpc_delay(task, 5*HZ);
1209                         goto retry_timeout;
1210                 }
1211                 status = task->tk_status;
1212                 break;
1213         default:
1214                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1215                                 task->tk_pid, -task->tk_status);
1216         }
1217
1218         rpc_exit(task, status);
1219         return;
1220
1221 retry_timeout:
1222         task->tk_action = call_timeout;
1223 }
1224
1225 /*
1226  * 4b.  Connect to the RPC server
1227  */
1228 static void
1229 call_connect(struct rpc_task *task)
1230 {
1231         struct rpc_xprt *xprt = task->tk_xprt;
1232
1233         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1234                         task->tk_pid, xprt,
1235                         (xprt_connected(xprt) ? "is" : "is not"));
1236
1237         task->tk_action = call_transmit;
1238         if (!xprt_connected(xprt)) {
1239                 task->tk_action = call_connect_status;
1240                 if (task->tk_status < 0)
1241                         return;
1242                 xprt_connect(task);
1243         }
1244 }
1245
1246 /*
1247  * 4c.  Sort out connect result
1248  */
1249 static void
1250 call_connect_status(struct rpc_task *task)
1251 {
1252         struct rpc_clnt *clnt = task->tk_client;
1253         int status = task->tk_status;
1254
1255         dprint_status(task);
1256
1257         task->tk_status = 0;
1258         if (status >= 0 || status == -EAGAIN) {
1259                 clnt->cl_stats->netreconn++;
1260                 task->tk_action = call_transmit;
1261                 return;
1262         }
1263
1264         switch (status) {
1265                 /* if soft mounted, test if we've timed out */
1266         case -ETIMEDOUT:
1267                 task->tk_action = call_timeout;
1268                 break;
1269         default:
1270                 rpc_exit(task, -EIO);
1271         }
1272 }
1273
1274 /*
1275  * 5.   Transmit the RPC request, and wait for reply
1276  */
1277 static void
1278 call_transmit(struct rpc_task *task)
1279 {
1280         dprint_status(task);
1281
1282         task->tk_action = call_status;
1283         if (task->tk_status < 0)
1284                 return;
1285         task->tk_status = xprt_prepare_transmit(task);
1286         if (task->tk_status != 0)
1287                 return;
1288         task->tk_action = call_transmit_status;
1289         /* Encode here so that rpcsec_gss can use correct sequence number. */
1290         if (rpc_task_need_encode(task)) {
1291                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1292                 rpc_xdr_encode(task);
1293                 /* Did the encode result in an error condition? */
1294                 if (task->tk_status != 0) {
1295                         /* Was the error nonfatal? */
1296                         if (task->tk_status == -EAGAIN)
1297                                 rpc_delay(task, HZ >> 4);
1298                         else
1299                                 rpc_exit(task, task->tk_status);
1300                         return;
1301                 }
1302         }
1303         xprt_transmit(task);
1304         if (task->tk_status < 0)
1305                 return;
1306         /*
1307          * On success, ensure that we call xprt_end_transmit() before sleeping
1308          * in order to allow access to the socket to other RPC requests.
1309          */
1310         call_transmit_status(task);
1311         if (rpc_reply_expected(task))
1312                 return;
1313         task->tk_action = rpc_exit_task;
1314         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1315 }
1316
1317 /*
1318  * 5a.  Handle cleanup after a transmission
1319  */
1320 static void
1321 call_transmit_status(struct rpc_task *task)
1322 {
1323         task->tk_action = call_status;
1324
1325         /*
1326          * Common case: success.  Force the compiler to put this
1327          * test first.
1328          */
1329         if (task->tk_status == 0) {
1330                 xprt_end_transmit(task);
1331                 rpc_task_force_reencode(task);
1332                 return;
1333         }
1334
1335         switch (task->tk_status) {
1336         case -EAGAIN:
1337                 break;
1338         default:
1339                 dprint_status(task);
1340                 xprt_end_transmit(task);
1341                 rpc_task_force_reencode(task);
1342                 break;
1343                 /*
1344                  * Special cases: if we've been waiting on the
1345                  * socket's write_space() callback, or if the
1346                  * socket just returned a connection error,
1347                  * then hold onto the transport lock.
1348                  */
1349         case -ECONNREFUSED:
1350         case -EHOSTDOWN:
1351         case -EHOSTUNREACH:
1352         case -ENETUNREACH:
1353                 if (RPC_IS_SOFTCONN(task)) {
1354                         xprt_end_transmit(task);
1355                         rpc_exit(task, task->tk_status);
1356                         break;
1357                 }
1358         case -ECONNRESET:
1359         case -ENOTCONN:
1360         case -EPIPE:
1361                 rpc_task_force_reencode(task);
1362         }
1363 }
1364
1365 #if defined(CONFIG_NFS_V4_1)
1366 /*
1367  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1368  * addition, disconnect on connectivity errors.
1369  */
1370 static void
1371 call_bc_transmit(struct rpc_task *task)
1372 {
1373         struct rpc_rqst *req = task->tk_rqstp;
1374
1375         BUG_ON(task->tk_status != 0);
1376         task->tk_status = xprt_prepare_transmit(task);
1377         if (task->tk_status == -EAGAIN) {
1378                 /*
1379                  * Could not reserve the transport. Try again after the
1380                  * transport is released.
1381                  */
1382                 task->tk_status = 0;
1383                 task->tk_action = call_bc_transmit;
1384                 return;
1385         }
1386
1387         task->tk_action = rpc_exit_task;
1388         if (task->tk_status < 0) {
1389                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1390                         "error: %d\n", task->tk_status);
1391                 return;
1392         }
1393
1394         xprt_transmit(task);
1395         xprt_end_transmit(task);
1396         dprint_status(task);
1397         switch (task->tk_status) {
1398         case 0:
1399                 /* Success */
1400                 break;
1401         case -EHOSTDOWN:
1402         case -EHOSTUNREACH:
1403         case -ENETUNREACH:
1404         case -ETIMEDOUT:
1405                 /*
1406                  * Problem reaching the server.  Disconnect and let the
1407                  * forechannel reestablish the connection.  The server will
1408                  * have to retransmit the backchannel request and we'll
1409                  * reprocess it.  Since these ops are idempotent, there's no
1410                  * need to cache our reply at this time.
1411                  */
1412                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1413                         "error: %d\n", task->tk_status);
1414                 xprt_conditional_disconnect(task->tk_xprt,
1415                         req->rq_connect_cookie);
1416                 break;
1417         default:
1418                 /*
1419                  * We were unable to reply and will have to drop the
1420                  * request.  The server should reconnect and retransmit.
1421                  */
1422                 BUG_ON(task->tk_status == -EAGAIN);
1423                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1424                         "error: %d\n", task->tk_status);
1425                 break;
1426         }
1427         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1428 }
1429 #endif /* CONFIG_NFS_V4_1 */
1430
1431 /*
1432  * 6.   Sort out the RPC call status
1433  */
1434 static void
1435 call_status(struct rpc_task *task)
1436 {
1437         struct rpc_clnt *clnt = task->tk_client;
1438         struct rpc_rqst *req = task->tk_rqstp;
1439         int             status;
1440
1441         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1442                 task->tk_status = req->rq_reply_bytes_recvd;
1443
1444         dprint_status(task);
1445
1446         status = task->tk_status;
1447         if (status >= 0) {
1448                 task->tk_action = call_decode;
1449                 return;
1450         }
1451
1452         task->tk_status = 0;
1453         switch(status) {
1454         case -EHOSTDOWN:
1455         case -EHOSTUNREACH:
1456         case -ENETUNREACH:
1457                 /*
1458                  * Delay any retries for 3 seconds, then handle as if it
1459                  * were a timeout.
1460                  */
1461                 rpc_delay(task, 3*HZ);
1462         case -ETIMEDOUT:
1463                 task->tk_action = call_timeout;
1464                 if (task->tk_client->cl_discrtry)
1465                         xprt_conditional_disconnect(task->tk_xprt,
1466                                         req->rq_connect_cookie);
1467                 break;
1468         case -ECONNRESET:
1469         case -ECONNREFUSED:
1470                 rpc_force_rebind(clnt);
1471                 rpc_delay(task, 3*HZ);
1472         case -EPIPE:
1473         case -ENOTCONN:
1474                 task->tk_action = call_bind;
1475                 break;
1476         case -EAGAIN:
1477                 task->tk_action = call_transmit;
1478                 break;
1479         case -EIO:
1480                 /* shutdown or soft timeout */
1481                 rpc_exit(task, status);
1482                 break;
1483         default:
1484                 if (clnt->cl_chatty)
1485                         printk("%s: RPC call returned error %d\n",
1486                                clnt->cl_protname, -status);
1487                 rpc_exit(task, status);
1488         }
1489 }
1490
1491 /*
1492  * 6a.  Handle RPC timeout
1493  *      We do not release the request slot, so we keep using the
1494  *      same XID for all retransmits.
1495  */
1496 static void
1497 call_timeout(struct rpc_task *task)
1498 {
1499         struct rpc_clnt *clnt = task->tk_client;
1500
1501         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1502                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1503                 goto retry;
1504         }
1505
1506         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1507         task->tk_timeouts++;
1508
1509         if (RPC_IS_SOFTCONN(task)) {
1510                 rpc_exit(task, -ETIMEDOUT);
1511                 return;
1512         }
1513         if (RPC_IS_SOFT(task)) {
1514                 if (clnt->cl_chatty)
1515                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1516                                 clnt->cl_protname, clnt->cl_server);
1517                 if (task->tk_flags & RPC_TASK_TIMEOUT)
1518                         rpc_exit(task, -ETIMEDOUT);
1519                 else
1520                         rpc_exit(task, -EIO);
1521                 return;
1522         }
1523
1524         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1525                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1526                 if (clnt->cl_chatty)
1527                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1528                         clnt->cl_protname, clnt->cl_server);
1529         }
1530         rpc_force_rebind(clnt);
1531         /*
1532          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1533          * event? RFC2203 requires the server to drop all such requests.
1534          */
1535         rpcauth_invalcred(task);
1536
1537 retry:
1538         clnt->cl_stats->rpcretrans++;
1539         task->tk_action = call_bind;
1540         task->tk_status = 0;
1541 }
1542
1543 /*
1544  * 7.   Decode the RPC reply
1545  */
1546 static void
1547 call_decode(struct rpc_task *task)
1548 {
1549         struct rpc_clnt *clnt = task->tk_client;
1550         struct rpc_rqst *req = task->tk_rqstp;
1551         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
1552         __be32          *p;
1553
1554         dprintk("RPC: %5u call_decode (status %d)\n",
1555                         task->tk_pid, task->tk_status);
1556
1557         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1558                 if (clnt->cl_chatty)
1559                         printk(KERN_NOTICE "%s: server %s OK\n",
1560                                 clnt->cl_protname, clnt->cl_server);
1561                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1562         }
1563
1564         /*
1565          * Ensure that we see all writes made by xprt_complete_rqst()
1566          * before it changed req->rq_reply_bytes_recvd.
1567          */
1568         smp_rmb();
1569         req->rq_rcv_buf.len = req->rq_private_buf.len;
1570
1571         /* Check that the softirq receive buffer is valid */
1572         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1573                                 sizeof(req->rq_rcv_buf)) != 0);
1574
1575         if (req->rq_rcv_buf.len < 12) {
1576                 if (!RPC_IS_SOFT(task)) {
1577                         task->tk_action = call_bind;
1578                         clnt->cl_stats->rpcretrans++;
1579                         goto out_retry;
1580                 }
1581                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1582                                 clnt->cl_protname, task->tk_status);
1583                 task->tk_action = call_timeout;
1584                 goto out_retry;
1585         }
1586
1587         p = rpc_verify_header(task);
1588         if (IS_ERR(p)) {
1589                 if (p == ERR_PTR(-EAGAIN))
1590                         goto out_retry;
1591                 return;
1592         }
1593
1594         task->tk_action = rpc_exit_task;
1595
1596         if (decode) {
1597                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1598                                                       task->tk_msg.rpc_resp);
1599         }
1600         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1601                         task->tk_status);
1602         return;
1603 out_retry:
1604         task->tk_status = 0;
1605         /* Note: rpc_verify_header() may have freed the RPC slot */
1606         if (task->tk_rqstp == req) {
1607                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
1608                 if (task->tk_client->cl_discrtry)
1609                         xprt_conditional_disconnect(task->tk_xprt,
1610                                         req->rq_connect_cookie);
1611         }
1612 }
1613
1614 static __be32 *
1615 rpc_encode_header(struct rpc_task *task)
1616 {
1617         struct rpc_clnt *clnt = task->tk_client;
1618         struct rpc_rqst *req = task->tk_rqstp;
1619         __be32          *p = req->rq_svec[0].iov_base;
1620
1621         /* FIXME: check buffer size? */
1622
1623         p = xprt_skip_transport_header(task->tk_xprt, p);
1624         *p++ = req->rq_xid;             /* XID */
1625         *p++ = htonl(RPC_CALL);         /* CALL */
1626         *p++ = htonl(RPC_VERSION);      /* RPC version */
1627         *p++ = htonl(clnt->cl_prog);    /* program number */
1628         *p++ = htonl(clnt->cl_vers);    /* program version */
1629         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1630         p = rpcauth_marshcred(task, p);
1631         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1632         return p;
1633 }
1634
1635 static __be32 *
1636 rpc_verify_header(struct rpc_task *task)
1637 {
1638         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1639         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1640         __be32  *p = iov->iov_base;
1641         u32 n;
1642         int error = -EACCES;
1643
1644         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1645                 /* RFC-1014 says that the representation of XDR data must be a
1646                  * multiple of four bytes
1647                  * - if it isn't pointer subtraction in the NFS client may give
1648                  *   undefined results
1649                  */
1650                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1651                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1652                        task->tk_rqstp->rq_rcv_buf.len);
1653                 goto out_eio;
1654         }
1655         if ((len -= 3) < 0)
1656                 goto out_overflow;
1657
1658         p += 1; /* skip XID */
1659         if ((n = ntohl(*p++)) != RPC_REPLY) {
1660                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1661                         task->tk_pid, __func__, n);
1662                 goto out_garbage;
1663         }
1664
1665         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1666                 if (--len < 0)
1667                         goto out_overflow;
1668                 switch ((n = ntohl(*p++))) {
1669                         case RPC_AUTH_ERROR:
1670                                 break;
1671                         case RPC_MISMATCH:
1672                                 dprintk("RPC: %5u %s: RPC call version "
1673                                                 "mismatch!\n",
1674                                                 task->tk_pid, __func__);
1675                                 error = -EPROTONOSUPPORT;
1676                                 goto out_err;
1677                         default:
1678                                 dprintk("RPC: %5u %s: RPC call rejected, "
1679                                                 "unknown error: %x\n",
1680                                                 task->tk_pid, __func__, n);
1681                                 goto out_eio;
1682                 }
1683                 if (--len < 0)
1684                         goto out_overflow;
1685                 switch ((n = ntohl(*p++))) {
1686                 case RPC_AUTH_REJECTEDCRED:
1687                 case RPC_AUTH_REJECTEDVERF:
1688                 case RPCSEC_GSS_CREDPROBLEM:
1689                 case RPCSEC_GSS_CTXPROBLEM:
1690                         if (!task->tk_cred_retry)
1691                                 break;
1692                         task->tk_cred_retry--;
1693                         dprintk("RPC: %5u %s: retry stale creds\n",
1694                                         task->tk_pid, __func__);
1695                         rpcauth_invalcred(task);
1696                         /* Ensure we obtain a new XID! */
1697                         xprt_release(task);
1698                         task->tk_action = call_reserve;
1699                         goto out_retry;
1700                 case RPC_AUTH_BADCRED:
1701                 case RPC_AUTH_BADVERF:
1702                         /* possibly garbled cred/verf? */
1703                         if (!task->tk_garb_retry)
1704                                 break;
1705                         task->tk_garb_retry--;
1706                         dprintk("RPC: %5u %s: retry garbled creds\n",
1707                                         task->tk_pid, __func__);
1708                         task->tk_action = call_bind;
1709                         goto out_retry;
1710                 case RPC_AUTH_TOOWEAK:
1711                         printk(KERN_NOTICE "RPC: server %s requires stronger "
1712                                "authentication.\n", task->tk_client->cl_server);
1713                         break;
1714                 default:
1715                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1716                                         task->tk_pid, __func__, n);
1717                         error = -EIO;
1718                 }
1719                 dprintk("RPC: %5u %s: call rejected %d\n",
1720                                 task->tk_pid, __func__, n);
1721                 goto out_err;
1722         }
1723         if (!(p = rpcauth_checkverf(task, p))) {
1724                 dprintk("RPC: %5u %s: auth check failed\n",
1725                                 task->tk_pid, __func__);
1726                 goto out_garbage;               /* bad verifier, retry */
1727         }
1728         len = p - (__be32 *)iov->iov_base - 1;
1729         if (len < 0)
1730                 goto out_overflow;
1731         switch ((n = ntohl(*p++))) {
1732         case RPC_SUCCESS:
1733                 return p;
1734         case RPC_PROG_UNAVAIL:
1735                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1736                                 task->tk_pid, __func__,
1737                                 (unsigned int)task->tk_client->cl_prog,
1738                                 task->tk_client->cl_server);
1739                 error = -EPFNOSUPPORT;
1740                 goto out_err;
1741         case RPC_PROG_MISMATCH:
1742                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1743                                 "server %s\n", task->tk_pid, __func__,
1744                                 (unsigned int)task->tk_client->cl_prog,
1745                                 (unsigned int)task->tk_client->cl_vers,
1746                                 task->tk_client->cl_server);
1747                 error = -EPROTONOSUPPORT;
1748                 goto out_err;
1749         case RPC_PROC_UNAVAIL:
1750                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1751                                 "version %u on server %s\n",
1752                                 task->tk_pid, __func__,
1753                                 rpc_proc_name(task),
1754                                 task->tk_client->cl_prog,
1755                                 task->tk_client->cl_vers,
1756                                 task->tk_client->cl_server);
1757                 error = -EOPNOTSUPP;
1758                 goto out_err;
1759         case RPC_GARBAGE_ARGS:
1760                 dprintk("RPC: %5u %s: server saw garbage\n",
1761                                 task->tk_pid, __func__);
1762                 break;                  /* retry */
1763         default:
1764                 dprintk("RPC: %5u %s: server accept status: %x\n",
1765                                 task->tk_pid, __func__, n);
1766                 /* Also retry */
1767         }
1768
1769 out_garbage:
1770         task->tk_client->cl_stats->rpcgarbage++;
1771         if (task->tk_garb_retry) {
1772                 task->tk_garb_retry--;
1773                 dprintk("RPC: %5u %s: retrying\n",
1774                                 task->tk_pid, __func__);
1775                 task->tk_action = call_bind;
1776 out_retry:
1777                 return ERR_PTR(-EAGAIN);
1778         }
1779 out_eio:
1780         error = -EIO;
1781 out_err:
1782         rpc_exit(task, error);
1783         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1784                         __func__, error);
1785         return ERR_PTR(error);
1786 out_overflow:
1787         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1788                         __func__);
1789         goto out_garbage;
1790 }
1791
1792 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1793 {
1794 }
1795
1796 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1797 {
1798         return 0;
1799 }
1800
1801 static struct rpc_procinfo rpcproc_null = {
1802         .p_encode = rpcproc_encode_null,
1803         .p_decode = rpcproc_decode_null,
1804 };
1805
1806 static int rpc_ping(struct rpc_clnt *clnt)
1807 {
1808         struct rpc_message msg = {
1809                 .rpc_proc = &rpcproc_null,
1810         };
1811         int err;
1812         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1813         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
1814         put_rpccred(msg.rpc_cred);
1815         return err;
1816 }
1817
1818 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1819 {
1820         struct rpc_message msg = {
1821                 .rpc_proc = &rpcproc_null,
1822                 .rpc_cred = cred,
1823         };
1824         struct rpc_task_setup task_setup_data = {
1825                 .rpc_client = clnt,
1826                 .rpc_message = &msg,
1827                 .callback_ops = &rpc_default_ops,
1828                 .flags = flags,
1829         };
1830         return rpc_run_task(&task_setup_data);
1831 }
1832 EXPORT_SYMBOL_GPL(rpc_call_null);
1833
1834 #ifdef RPC_DEBUG
1835 static void rpc_show_header(void)
1836 {
1837         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1838                 "-timeout ---ops--\n");
1839 }
1840
1841 static void rpc_show_task(const struct rpc_clnt *clnt,
1842                           const struct rpc_task *task)
1843 {
1844         const char *rpc_waitq = "none";
1845
1846         if (RPC_IS_QUEUED(task))
1847                 rpc_waitq = rpc_qname(task->tk_waitqueue);
1848
1849         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
1850                 task->tk_pid, task->tk_flags, task->tk_status,
1851                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1852                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1853                 task->tk_action, rpc_waitq);
1854 }
1855
1856 void rpc_show_tasks(void)
1857 {
1858         struct rpc_clnt *clnt;
1859         struct rpc_task *task;
1860         int header = 0;
1861
1862         spin_lock(&rpc_client_lock);
1863         list_for_each_entry(clnt, &all_clients, cl_clients) {
1864                 spin_lock(&clnt->cl_lock);
1865                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1866                         if (!header) {
1867                                 rpc_show_header();
1868                                 header++;
1869                         }
1870                         rpc_show_task(clnt, task);
1871                 }
1872                 spin_unlock(&clnt->cl_lock);
1873         }
1874         spin_unlock(&rpc_client_lock);
1875 }
1876 #endif