Merge branch 'nfs-for-next' of git://linux-nfs.org/~trondmy/nfs-2.6 into for-3.10
[linux-3.10.git] / 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
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kallsyms.h>
24 #include <linux/mm.h>
25 #include <linux/namei.h>
26 #include <linux/mount.h>
27 #include <linux/slab.h>
28 #include <linux/utsname.h>
29 #include <linux/workqueue.h>
30 #include <linux/in.h>
31 #include <linux/in6.h>
32 #include <linux/un.h>
33 #include <linux/rcupdate.h>
34
35 #include <linux/sunrpc/clnt.h>
36 #include <linux/sunrpc/addr.h>
37 #include <linux/sunrpc/rpc_pipe_fs.h>
38 #include <linux/sunrpc/metrics.h>
39 #include <linux/sunrpc/bc_xprt.h>
40 #include <trace/events/sunrpc.h>
41
42 #include "sunrpc.h"
43 #include "netns.h"
44
45 #ifdef RPC_DEBUG
46 # define RPCDBG_FACILITY        RPCDBG_CALL
47 #endif
48
49 #define dprint_status(t)                                        \
50         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
51                         __func__, t->tk_status)
52
53 /*
54  * All RPC clients are linked into this list
55  */
56
57 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
58
59
60 static void     call_start(struct rpc_task *task);
61 static void     call_reserve(struct rpc_task *task);
62 static void     call_reserveresult(struct rpc_task *task);
63 static void     call_allocate(struct rpc_task *task);
64 static void     call_decode(struct rpc_task *task);
65 static void     call_bind(struct rpc_task *task);
66 static void     call_bind_status(struct rpc_task *task);
67 static void     call_transmit(struct rpc_task *task);
68 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
69 static void     call_bc_transmit(struct rpc_task *task);
70 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
71 static void     call_status(struct rpc_task *task);
72 static void     call_transmit_status(struct rpc_task *task);
73 static void     call_refresh(struct rpc_task *task);
74 static void     call_refreshresult(struct rpc_task *task);
75 static void     call_timeout(struct rpc_task *task);
76 static void     call_connect(struct rpc_task *task);
77 static void     call_connect_status(struct rpc_task *task);
78
79 static __be32   *rpc_encode_header(struct rpc_task *task);
80 static __be32   *rpc_verify_header(struct rpc_task *task);
81 static int      rpc_ping(struct rpc_clnt *clnt);
82
83 static void rpc_register_client(struct rpc_clnt *clnt)
84 {
85         struct net *net = rpc_net_ns(clnt);
86         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
87
88         spin_lock(&sn->rpc_client_lock);
89         list_add(&clnt->cl_clients, &sn->all_clients);
90         spin_unlock(&sn->rpc_client_lock);
91 }
92
93 static void rpc_unregister_client(struct rpc_clnt *clnt)
94 {
95         struct net *net = rpc_net_ns(clnt);
96         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
97
98         spin_lock(&sn->rpc_client_lock);
99         list_del(&clnt->cl_clients);
100         spin_unlock(&sn->rpc_client_lock);
101 }
102
103 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
104 {
105         if (clnt->cl_dentry) {
106                 if (clnt->cl_auth && clnt->cl_auth->au_ops->pipes_destroy)
107                         clnt->cl_auth->au_ops->pipes_destroy(clnt->cl_auth);
108                 rpc_remove_client_dir(clnt->cl_dentry);
109         }
110         clnt->cl_dentry = NULL;
111 }
112
113 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
114 {
115         struct net *net = rpc_net_ns(clnt);
116         struct super_block *pipefs_sb;
117
118         pipefs_sb = rpc_get_sb_net(net);
119         if (pipefs_sb) {
120                 __rpc_clnt_remove_pipedir(clnt);
121                 rpc_put_sb_net(net);
122         }
123 }
124
125 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
126                                     struct rpc_clnt *clnt,
127                                     const char *dir_name)
128 {
129         static uint32_t clntid;
130         char name[15];
131         struct qstr q = { .name = name };
132         struct dentry *dir, *dentry;
133         int error;
134
135         dir = rpc_d_lookup_sb(sb, dir_name);
136         if (dir == NULL) {
137                 pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
138                 return dir;
139         }
140         for (;;) {
141                 q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
142                 name[sizeof(name) - 1] = '\0';
143                 q.hash = full_name_hash(q.name, q.len);
144                 dentry = rpc_create_client_dir(dir, &q, clnt);
145                 if (!IS_ERR(dentry))
146                         break;
147                 error = PTR_ERR(dentry);
148                 if (error != -EEXIST) {
149                         printk(KERN_INFO "RPC: Couldn't create pipefs entry"
150                                         " %s/%s, error %d\n",
151                                         dir_name, name, error);
152                         break;
153                 }
154         }
155         dput(dir);
156         return dentry;
157 }
158
159 static int
160 rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name)
161 {
162         struct net *net = rpc_net_ns(clnt);
163         struct super_block *pipefs_sb;
164         struct dentry *dentry;
165
166         clnt->cl_dentry = NULL;
167         if (dir_name == NULL)
168                 return 0;
169         pipefs_sb = rpc_get_sb_net(net);
170         if (!pipefs_sb)
171                 return 0;
172         dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt, dir_name);
173         rpc_put_sb_net(net);
174         if (IS_ERR(dentry))
175                 return PTR_ERR(dentry);
176         clnt->cl_dentry = dentry;
177         return 0;
178 }
179
180 static inline int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
181 {
182         if (((event == RPC_PIPEFS_MOUNT) && clnt->cl_dentry) ||
183             ((event == RPC_PIPEFS_UMOUNT) && !clnt->cl_dentry))
184                 return 1;
185         return 0;
186 }
187
188 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
189                                    struct super_block *sb)
190 {
191         struct dentry *dentry;
192         int err = 0;
193
194         switch (event) {
195         case RPC_PIPEFS_MOUNT:
196                 dentry = rpc_setup_pipedir_sb(sb, clnt,
197                                               clnt->cl_program->pipe_dir_name);
198                 if (!dentry)
199                         return -ENOENT;
200                 if (IS_ERR(dentry))
201                         return PTR_ERR(dentry);
202                 clnt->cl_dentry = dentry;
203                 if (clnt->cl_auth->au_ops->pipes_create) {
204                         err = clnt->cl_auth->au_ops->pipes_create(clnt->cl_auth);
205                         if (err)
206                                 __rpc_clnt_remove_pipedir(clnt);
207                 }
208                 break;
209         case RPC_PIPEFS_UMOUNT:
210                 __rpc_clnt_remove_pipedir(clnt);
211                 break;
212         default:
213                 printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
214                 return -ENOTSUPP;
215         }
216         return err;
217 }
218
219 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
220                                 struct super_block *sb)
221 {
222         int error = 0;
223
224         for (;; clnt = clnt->cl_parent) {
225                 if (!rpc_clnt_skip_event(clnt, event))
226                         error = __rpc_clnt_handle_event(clnt, event, sb);
227                 if (error || clnt == clnt->cl_parent)
228                         break;
229         }
230         return error;
231 }
232
233 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
234 {
235         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
236         struct rpc_clnt *clnt;
237
238         spin_lock(&sn->rpc_client_lock);
239         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
240                 if (clnt->cl_program->pipe_dir_name == NULL)
241                         continue;
242                 if (rpc_clnt_skip_event(clnt, event))
243                         continue;
244                 if (atomic_inc_not_zero(&clnt->cl_count) == 0)
245                         continue;
246                 spin_unlock(&sn->rpc_client_lock);
247                 return clnt;
248         }
249         spin_unlock(&sn->rpc_client_lock);
250         return NULL;
251 }
252
253 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
254                             void *ptr)
255 {
256         struct super_block *sb = ptr;
257         struct rpc_clnt *clnt;
258         int error = 0;
259
260         while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
261                 error = __rpc_pipefs_event(clnt, event, sb);
262                 rpc_release_client(clnt);
263                 if (error)
264                         break;
265         }
266         return error;
267 }
268
269 static struct notifier_block rpc_clients_block = {
270         .notifier_call  = rpc_pipefs_event,
271         .priority       = SUNRPC_PIPEFS_RPC_PRIO,
272 };
273
274 int rpc_clients_notifier_register(void)
275 {
276         return rpc_pipefs_notifier_register(&rpc_clients_block);
277 }
278
279 void rpc_clients_notifier_unregister(void)
280 {
281         return rpc_pipefs_notifier_unregister(&rpc_clients_block);
282 }
283
284 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
285 {
286         clnt->cl_nodelen = strlen(nodename);
287         if (clnt->cl_nodelen > UNX_MAXNODENAME)
288                 clnt->cl_nodelen = UNX_MAXNODENAME;
289         memcpy(clnt->cl_nodename, nodename, clnt->cl_nodelen);
290 }
291
292 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
293 {
294         const struct rpc_program *program = args->program;
295         const struct rpc_version *version;
296         struct rpc_clnt         *clnt = NULL;
297         struct rpc_auth         *auth;
298         int err;
299
300         /* sanity check the name before trying to print it */
301         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
302                         program->name, args->servername, xprt);
303
304         err = rpciod_up();
305         if (err)
306                 goto out_no_rpciod;
307
308         err = -EINVAL;
309         if (args->version >= program->nrvers)
310                 goto out_err;
311         version = program->version[args->version];
312         if (version == NULL)
313                 goto out_err;
314
315         err = -ENOMEM;
316         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
317         if (!clnt)
318                 goto out_err;
319         clnt->cl_parent = clnt;
320
321         rcu_assign_pointer(clnt->cl_xprt, xprt);
322         clnt->cl_procinfo = version->procs;
323         clnt->cl_maxproc  = version->nrprocs;
324         clnt->cl_protname = program->name;
325         clnt->cl_prog     = args->prognumber ? : program->number;
326         clnt->cl_vers     = version->number;
327         clnt->cl_stats    = program->stats;
328         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
329         err = -ENOMEM;
330         if (clnt->cl_metrics == NULL)
331                 goto out_no_stats;
332         clnt->cl_program  = program;
333         INIT_LIST_HEAD(&clnt->cl_tasks);
334         spin_lock_init(&clnt->cl_lock);
335
336         if (!xprt_bound(xprt))
337                 clnt->cl_autobind = 1;
338
339         clnt->cl_timeout = xprt->timeout;
340         if (args->timeout != NULL) {
341                 memcpy(&clnt->cl_timeout_default, args->timeout,
342                                 sizeof(clnt->cl_timeout_default));
343                 clnt->cl_timeout = &clnt->cl_timeout_default;
344         }
345
346         clnt->cl_rtt = &clnt->cl_rtt_default;
347         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
348         clnt->cl_principal = NULL;
349         if (args->client_name) {
350                 clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
351                 if (!clnt->cl_principal)
352                         goto out_no_principal;
353         }
354
355         atomic_set(&clnt->cl_count, 1);
356
357         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
358         if (err < 0)
359                 goto out_no_path;
360
361         auth = rpcauth_create(args->authflavor, clnt);
362         if (IS_ERR(auth)) {
363                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
364                                 args->authflavor);
365                 err = PTR_ERR(auth);
366                 goto out_no_auth;
367         }
368
369         /* save the nodename */
370         rpc_clnt_set_nodename(clnt, utsname()->nodename);
371         rpc_register_client(clnt);
372         return clnt;
373
374 out_no_auth:
375         rpc_clnt_remove_pipedir(clnt);
376 out_no_path:
377         kfree(clnt->cl_principal);
378 out_no_principal:
379         rpc_free_iostats(clnt->cl_metrics);
380 out_no_stats:
381         kfree(clnt);
382 out_err:
383         rpciod_down();
384 out_no_rpciod:
385         xprt_put(xprt);
386         return ERR_PTR(err);
387 }
388
389 /**
390  * rpc_create - create an RPC client and transport with one call
391  * @args: rpc_clnt create argument structure
392  *
393  * Creates and initializes an RPC transport and an RPC client.
394  *
395  * It can ping the server in order to determine if it is up, and to see if
396  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
397  * this behavior so asynchronous tasks can also use rpc_create.
398  */
399 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
400 {
401         struct rpc_xprt *xprt;
402         struct rpc_clnt *clnt;
403         struct xprt_create xprtargs = {
404                 .net = args->net,
405                 .ident = args->protocol,
406                 .srcaddr = args->saddress,
407                 .dstaddr = args->address,
408                 .addrlen = args->addrsize,
409                 .servername = args->servername,
410                 .bc_xprt = args->bc_xprt,
411         };
412         char servername[48];
413
414         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
415                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
416         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
417                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
418         /*
419          * If the caller chooses not to specify a hostname, whip
420          * up a string representation of the passed-in address.
421          */
422         if (xprtargs.servername == NULL) {
423                 struct sockaddr_un *sun =
424                                 (struct sockaddr_un *)args->address;
425                 struct sockaddr_in *sin =
426                                 (struct sockaddr_in *)args->address;
427                 struct sockaddr_in6 *sin6 =
428                                 (struct sockaddr_in6 *)args->address;
429
430                 servername[0] = '\0';
431                 switch (args->address->sa_family) {
432                 case AF_LOCAL:
433                         snprintf(servername, sizeof(servername), "%s",
434                                  sun->sun_path);
435                         break;
436                 case AF_INET:
437                         snprintf(servername, sizeof(servername), "%pI4",
438                                  &sin->sin_addr.s_addr);
439                         break;
440                 case AF_INET6:
441                         snprintf(servername, sizeof(servername), "%pI6",
442                                  &sin6->sin6_addr);
443                         break;
444                 default:
445                         /* caller wants default server name, but
446                          * address family isn't recognized. */
447                         return ERR_PTR(-EINVAL);
448                 }
449                 xprtargs.servername = servername;
450         }
451
452         xprt = xprt_create_transport(&xprtargs);
453         if (IS_ERR(xprt))
454                 return (struct rpc_clnt *)xprt;
455
456         /*
457          * By default, kernel RPC client connects from a reserved port.
458          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
459          * but it is always enabled for rpciod, which handles the connect
460          * operation.
461          */
462         xprt->resvport = 1;
463         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
464                 xprt->resvport = 0;
465
466         clnt = rpc_new_client(args, xprt);
467         if (IS_ERR(clnt))
468                 return clnt;
469
470         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
471                 int err = rpc_ping(clnt);
472                 if (err != 0) {
473                         rpc_shutdown_client(clnt);
474                         return ERR_PTR(err);
475                 }
476         }
477
478         clnt->cl_softrtry = 1;
479         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
480                 clnt->cl_softrtry = 0;
481
482         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
483                 clnt->cl_autobind = 1;
484         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
485                 clnt->cl_discrtry = 1;
486         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
487                 clnt->cl_chatty = 1;
488
489         return clnt;
490 }
491 EXPORT_SYMBOL_GPL(rpc_create);
492
493 /*
494  * This function clones the RPC client structure. It allows us to share the
495  * same transport while varying parameters such as the authentication
496  * flavour.
497  */
498 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
499                                            struct rpc_clnt *clnt)
500 {
501         struct rpc_xprt *xprt;
502         struct rpc_clnt *new;
503         int err;
504
505         err = -ENOMEM;
506         rcu_read_lock();
507         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
508         rcu_read_unlock();
509         if (xprt == NULL)
510                 goto out_err;
511         args->servername = xprt->servername;
512
513         new = rpc_new_client(args, xprt);
514         if (IS_ERR(new)) {
515                 err = PTR_ERR(new);
516                 goto out_err;
517         }
518
519         atomic_inc(&clnt->cl_count);
520         new->cl_parent = clnt;
521
522         /* Turn off autobind on clones */
523         new->cl_autobind = 0;
524         new->cl_softrtry = clnt->cl_softrtry;
525         new->cl_discrtry = clnt->cl_discrtry;
526         new->cl_chatty = clnt->cl_chatty;
527         return new;
528
529 out_err:
530         dprintk("RPC:       %s: returned error %d\n", __func__, err);
531         return ERR_PTR(err);
532 }
533
534 /**
535  * rpc_clone_client - Clone an RPC client structure
536  *
537  * @clnt: RPC client whose parameters are copied
538  *
539  * Returns a fresh RPC client or an ERR_PTR.
540  */
541 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
542 {
543         struct rpc_create_args args = {
544                 .program        = clnt->cl_program,
545                 .prognumber     = clnt->cl_prog,
546                 .version        = clnt->cl_vers,
547                 .authflavor     = clnt->cl_auth->au_flavor,
548                 .client_name    = clnt->cl_principal,
549         };
550         return __rpc_clone_client(&args, clnt);
551 }
552 EXPORT_SYMBOL_GPL(rpc_clone_client);
553
554 /**
555  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
556  *
557  * @clnt: RPC client whose parameters are copied
558  * @flavor: security flavor for new client
559  *
560  * Returns a fresh RPC client or an ERR_PTR.
561  */
562 struct rpc_clnt *
563 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
564 {
565         struct rpc_create_args args = {
566                 .program        = clnt->cl_program,
567                 .prognumber     = clnt->cl_prog,
568                 .version        = clnt->cl_vers,
569                 .authflavor     = flavor,
570                 .client_name    = clnt->cl_principal,
571         };
572         return __rpc_clone_client(&args, clnt);
573 }
574 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
575
576 /*
577  * Kill all tasks for the given client.
578  * XXX: kill their descendants as well?
579  */
580 void rpc_killall_tasks(struct rpc_clnt *clnt)
581 {
582         struct rpc_task *rovr;
583
584
585         if (list_empty(&clnt->cl_tasks))
586                 return;
587         dprintk("RPC:       killing all tasks for client %p\n", clnt);
588         /*
589          * Spin lock all_tasks to prevent changes...
590          */
591         spin_lock(&clnt->cl_lock);
592         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
593                 if (!RPC_IS_ACTIVATED(rovr))
594                         continue;
595                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
596                         rovr->tk_flags |= RPC_TASK_KILLED;
597                         rpc_exit(rovr, -EIO);
598                         if (RPC_IS_QUEUED(rovr))
599                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
600                                                         rovr);
601                 }
602         }
603         spin_unlock(&clnt->cl_lock);
604 }
605 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
606
607 /*
608  * Properly shut down an RPC client, terminating all outstanding
609  * requests.
610  */
611 void rpc_shutdown_client(struct rpc_clnt *clnt)
612 {
613         might_sleep();
614
615         dprintk_rcu("RPC:       shutting down %s client for %s\n",
616                         clnt->cl_protname,
617                         rcu_dereference(clnt->cl_xprt)->servername);
618
619         while (!list_empty(&clnt->cl_tasks)) {
620                 rpc_killall_tasks(clnt);
621                 wait_event_timeout(destroy_wait,
622                         list_empty(&clnt->cl_tasks), 1*HZ);
623         }
624
625         rpc_release_client(clnt);
626 }
627 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
628
629 /*
630  * Free an RPC client
631  */
632 static void
633 rpc_free_client(struct rpc_clnt *clnt)
634 {
635         dprintk_rcu("RPC:       destroying %s client for %s\n",
636                         clnt->cl_protname,
637                         rcu_dereference(clnt->cl_xprt)->servername);
638         if (clnt->cl_parent != clnt)
639                 rpc_release_client(clnt->cl_parent);
640         rpc_unregister_client(clnt);
641         rpc_clnt_remove_pipedir(clnt);
642         rpc_free_iostats(clnt->cl_metrics);
643         kfree(clnt->cl_principal);
644         clnt->cl_metrics = NULL;
645         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
646         rpciod_down();
647         kfree(clnt);
648 }
649
650 /*
651  * Free an RPC client
652  */
653 static void
654 rpc_free_auth(struct rpc_clnt *clnt)
655 {
656         if (clnt->cl_auth == NULL) {
657                 rpc_free_client(clnt);
658                 return;
659         }
660
661         /*
662          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
663          *       release remaining GSS contexts. This mechanism ensures
664          *       that it can do so safely.
665          */
666         atomic_inc(&clnt->cl_count);
667         rpcauth_release(clnt->cl_auth);
668         clnt->cl_auth = NULL;
669         if (atomic_dec_and_test(&clnt->cl_count))
670                 rpc_free_client(clnt);
671 }
672
673 /*
674  * Release reference to the RPC client
675  */
676 void
677 rpc_release_client(struct rpc_clnt *clnt)
678 {
679         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
680
681         if (list_empty(&clnt->cl_tasks))
682                 wake_up(&destroy_wait);
683         if (atomic_dec_and_test(&clnt->cl_count))
684                 rpc_free_auth(clnt);
685 }
686 EXPORT_SYMBOL_GPL(rpc_release_client);
687
688 /**
689  * rpc_bind_new_program - bind a new RPC program to an existing client
690  * @old: old rpc_client
691  * @program: rpc program to set
692  * @vers: rpc program version
693  *
694  * Clones the rpc client and sets up a new RPC program. This is mainly
695  * of use for enabling different RPC programs to share the same transport.
696  * The Sun NFSv2/v3 ACL protocol can do this.
697  */
698 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
699                                       const struct rpc_program *program,
700                                       u32 vers)
701 {
702         struct rpc_create_args args = {
703                 .program        = program,
704                 .prognumber     = program->number,
705                 .version        = vers,
706                 .authflavor     = old->cl_auth->au_flavor,
707                 .client_name    = old->cl_principal,
708         };
709         struct rpc_clnt *clnt;
710         int err;
711
712         clnt = __rpc_clone_client(&args, old);
713         if (IS_ERR(clnt))
714                 goto out;
715         err = rpc_ping(clnt);
716         if (err != 0) {
717                 rpc_shutdown_client(clnt);
718                 clnt = ERR_PTR(err);
719         }
720 out:
721         return clnt;
722 }
723 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
724
725 void rpc_task_release_client(struct rpc_task *task)
726 {
727         struct rpc_clnt *clnt = task->tk_client;
728
729         if (clnt != NULL) {
730                 /* Remove from client task list */
731                 spin_lock(&clnt->cl_lock);
732                 list_del(&task->tk_task);
733                 spin_unlock(&clnt->cl_lock);
734                 task->tk_client = NULL;
735
736                 rpc_release_client(clnt);
737         }
738 }
739
740 static
741 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
742 {
743         if (clnt != NULL) {
744                 rpc_task_release_client(task);
745                 task->tk_client = clnt;
746                 atomic_inc(&clnt->cl_count);
747                 if (clnt->cl_softrtry)
748                         task->tk_flags |= RPC_TASK_SOFT;
749                 if (sk_memalloc_socks()) {
750                         struct rpc_xprt *xprt;
751
752                         rcu_read_lock();
753                         xprt = rcu_dereference(clnt->cl_xprt);
754                         if (xprt->swapper)
755                                 task->tk_flags |= RPC_TASK_SWAPPER;
756                         rcu_read_unlock();
757                 }
758                 /* Add to the client's list of all tasks */
759                 spin_lock(&clnt->cl_lock);
760                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
761                 spin_unlock(&clnt->cl_lock);
762         }
763 }
764
765 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
766 {
767         rpc_task_release_client(task);
768         rpc_task_set_client(task, clnt);
769 }
770 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
771
772
773 static void
774 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
775 {
776         if (msg != NULL) {
777                 task->tk_msg.rpc_proc = msg->rpc_proc;
778                 task->tk_msg.rpc_argp = msg->rpc_argp;
779                 task->tk_msg.rpc_resp = msg->rpc_resp;
780                 if (msg->rpc_cred != NULL)
781                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
782         }
783 }
784
785 /*
786  * Default callback for async RPC calls
787  */
788 static void
789 rpc_default_callback(struct rpc_task *task, void *data)
790 {
791 }
792
793 static const struct rpc_call_ops rpc_default_ops = {
794         .rpc_call_done = rpc_default_callback,
795 };
796
797 /**
798  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
799  * @task_setup_data: pointer to task initialisation data
800  */
801 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
802 {
803         struct rpc_task *task;
804
805         task = rpc_new_task(task_setup_data);
806         if (IS_ERR(task))
807                 goto out;
808
809         rpc_task_set_client(task, task_setup_data->rpc_client);
810         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
811
812         if (task->tk_action == NULL)
813                 rpc_call_start(task);
814
815         atomic_inc(&task->tk_count);
816         rpc_execute(task);
817 out:
818         return task;
819 }
820 EXPORT_SYMBOL_GPL(rpc_run_task);
821
822 /**
823  * rpc_call_sync - Perform a synchronous RPC call
824  * @clnt: pointer to RPC client
825  * @msg: RPC call parameters
826  * @flags: RPC call flags
827  */
828 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
829 {
830         struct rpc_task *task;
831         struct rpc_task_setup task_setup_data = {
832                 .rpc_client = clnt,
833                 .rpc_message = msg,
834                 .callback_ops = &rpc_default_ops,
835                 .flags = flags,
836         };
837         int status;
838
839         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
840         if (flags & RPC_TASK_ASYNC) {
841                 rpc_release_calldata(task_setup_data.callback_ops,
842                         task_setup_data.callback_data);
843                 return -EINVAL;
844         }
845
846         task = rpc_run_task(&task_setup_data);
847         if (IS_ERR(task))
848                 return PTR_ERR(task);
849         status = task->tk_status;
850         rpc_put_task(task);
851         return status;
852 }
853 EXPORT_SYMBOL_GPL(rpc_call_sync);
854
855 /**
856  * rpc_call_async - Perform an asynchronous RPC call
857  * @clnt: pointer to RPC client
858  * @msg: RPC call parameters
859  * @flags: RPC call flags
860  * @tk_ops: RPC call ops
861  * @data: user call data
862  */
863 int
864 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
865                const struct rpc_call_ops *tk_ops, void *data)
866 {
867         struct rpc_task *task;
868         struct rpc_task_setup task_setup_data = {
869                 .rpc_client = clnt,
870                 .rpc_message = msg,
871                 .callback_ops = tk_ops,
872                 .callback_data = data,
873                 .flags = flags|RPC_TASK_ASYNC,
874         };
875
876         task = rpc_run_task(&task_setup_data);
877         if (IS_ERR(task))
878                 return PTR_ERR(task);
879         rpc_put_task(task);
880         return 0;
881 }
882 EXPORT_SYMBOL_GPL(rpc_call_async);
883
884 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
885 /**
886  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
887  * rpc_execute against it
888  * @req: RPC request
889  * @tk_ops: RPC call ops
890  */
891 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
892                                 const struct rpc_call_ops *tk_ops)
893 {
894         struct rpc_task *task;
895         struct xdr_buf *xbufp = &req->rq_snd_buf;
896         struct rpc_task_setup task_setup_data = {
897                 .callback_ops = tk_ops,
898         };
899
900         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
901         /*
902          * Create an rpc_task to send the data
903          */
904         task = rpc_new_task(&task_setup_data);
905         if (IS_ERR(task)) {
906                 xprt_free_bc_request(req);
907                 goto out;
908         }
909         task->tk_rqstp = req;
910
911         /*
912          * Set up the xdr_buf length.
913          * This also indicates that the buffer is XDR encoded already.
914          */
915         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
916                         xbufp->tail[0].iov_len;
917
918         task->tk_action = call_bc_transmit;
919         atomic_inc(&task->tk_count);
920         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
921         rpc_execute(task);
922
923 out:
924         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
925         return task;
926 }
927 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
928
929 void
930 rpc_call_start(struct rpc_task *task)
931 {
932         task->tk_action = call_start;
933 }
934 EXPORT_SYMBOL_GPL(rpc_call_start);
935
936 /**
937  * rpc_peeraddr - extract remote peer address from clnt's xprt
938  * @clnt: RPC client structure
939  * @buf: target buffer
940  * @bufsize: length of target buffer
941  *
942  * Returns the number of bytes that are actually in the stored address.
943  */
944 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
945 {
946         size_t bytes;
947         struct rpc_xprt *xprt;
948
949         rcu_read_lock();
950         xprt = rcu_dereference(clnt->cl_xprt);
951
952         bytes = xprt->addrlen;
953         if (bytes > bufsize)
954                 bytes = bufsize;
955         memcpy(buf, &xprt->addr, bytes);
956         rcu_read_unlock();
957
958         return bytes;
959 }
960 EXPORT_SYMBOL_GPL(rpc_peeraddr);
961
962 /**
963  * rpc_peeraddr2str - return remote peer address in printable format
964  * @clnt: RPC client structure
965  * @format: address format
966  *
967  * NB: the lifetime of the memory referenced by the returned pointer is
968  * the same as the rpc_xprt itself.  As long as the caller uses this
969  * pointer, it must hold the RCU read lock.
970  */
971 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
972                              enum rpc_display_format_t format)
973 {
974         struct rpc_xprt *xprt;
975
976         xprt = rcu_dereference(clnt->cl_xprt);
977
978         if (xprt->address_strings[format] != NULL)
979                 return xprt->address_strings[format];
980         else
981                 return "unprintable";
982 }
983 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
984
985 static const struct sockaddr_in rpc_inaddr_loopback = {
986         .sin_family             = AF_INET,
987         .sin_addr.s_addr        = htonl(INADDR_ANY),
988 };
989
990 static const struct sockaddr_in6 rpc_in6addr_loopback = {
991         .sin6_family            = AF_INET6,
992         .sin6_addr              = IN6ADDR_ANY_INIT,
993 };
994
995 /*
996  * Try a getsockname() on a connected datagram socket.  Using a
997  * connected datagram socket prevents leaving a socket in TIME_WAIT.
998  * This conserves the ephemeral port number space.
999  *
1000  * Returns zero and fills in "buf" if successful; otherwise, a
1001  * negative errno is returned.
1002  */
1003 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1004                         struct sockaddr *buf, int buflen)
1005 {
1006         struct socket *sock;
1007         int err;
1008
1009         err = __sock_create(net, sap->sa_family,
1010                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1011         if (err < 0) {
1012                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1013                 goto out;
1014         }
1015
1016         switch (sap->sa_family) {
1017         case AF_INET:
1018                 err = kernel_bind(sock,
1019                                 (struct sockaddr *)&rpc_inaddr_loopback,
1020                                 sizeof(rpc_inaddr_loopback));
1021                 break;
1022         case AF_INET6:
1023                 err = kernel_bind(sock,
1024                                 (struct sockaddr *)&rpc_in6addr_loopback,
1025                                 sizeof(rpc_in6addr_loopback));
1026                 break;
1027         default:
1028                 err = -EAFNOSUPPORT;
1029                 goto out;
1030         }
1031         if (err < 0) {
1032                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1033                 goto out_release;
1034         }
1035
1036         err = kernel_connect(sock, sap, salen, 0);
1037         if (err < 0) {
1038                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1039                 goto out_release;
1040         }
1041
1042         err = kernel_getsockname(sock, buf, &buflen);
1043         if (err < 0) {
1044                 dprintk("RPC:       getsockname failed (%d)\n", err);
1045                 goto out_release;
1046         }
1047
1048         err = 0;
1049         if (buf->sa_family == AF_INET6) {
1050                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1051                 sin6->sin6_scope_id = 0;
1052         }
1053         dprintk("RPC:       %s succeeded\n", __func__);
1054
1055 out_release:
1056         sock_release(sock);
1057 out:
1058         return err;
1059 }
1060
1061 /*
1062  * Scraping a connected socket failed, so we don't have a useable
1063  * local address.  Fallback: generate an address that will prevent
1064  * the server from calling us back.
1065  *
1066  * Returns zero and fills in "buf" if successful; otherwise, a
1067  * negative errno is returned.
1068  */
1069 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1070 {
1071         switch (family) {
1072         case AF_INET:
1073                 if (buflen < sizeof(rpc_inaddr_loopback))
1074                         return -EINVAL;
1075                 memcpy(buf, &rpc_inaddr_loopback,
1076                                 sizeof(rpc_inaddr_loopback));
1077                 break;
1078         case AF_INET6:
1079                 if (buflen < sizeof(rpc_in6addr_loopback))
1080                         return -EINVAL;
1081                 memcpy(buf, &rpc_in6addr_loopback,
1082                                 sizeof(rpc_in6addr_loopback));
1083         default:
1084                 dprintk("RPC:       %s: address family not supported\n",
1085                         __func__);
1086                 return -EAFNOSUPPORT;
1087         }
1088         dprintk("RPC:       %s: succeeded\n", __func__);
1089         return 0;
1090 }
1091
1092 /**
1093  * rpc_localaddr - discover local endpoint address for an RPC client
1094  * @clnt: RPC client structure
1095  * @buf: target buffer
1096  * @buflen: size of target buffer, in bytes
1097  *
1098  * Returns zero and fills in "buf" and "buflen" if successful;
1099  * otherwise, a negative errno is returned.
1100  *
1101  * This works even if the underlying transport is not currently connected,
1102  * or if the upper layer never previously provided a source address.
1103  *
1104  * The result of this function call is transient: multiple calls in
1105  * succession may give different results, depending on how local
1106  * networking configuration changes over time.
1107  */
1108 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1109 {
1110         struct sockaddr_storage address;
1111         struct sockaddr *sap = (struct sockaddr *)&address;
1112         struct rpc_xprt *xprt;
1113         struct net *net;
1114         size_t salen;
1115         int err;
1116
1117         rcu_read_lock();
1118         xprt = rcu_dereference(clnt->cl_xprt);
1119         salen = xprt->addrlen;
1120         memcpy(sap, &xprt->addr, salen);
1121         net = get_net(xprt->xprt_net);
1122         rcu_read_unlock();
1123
1124         rpc_set_port(sap, 0);
1125         err = rpc_sockname(net, sap, salen, buf, buflen);
1126         put_net(net);
1127         if (err != 0)
1128                 /* Couldn't discover local address, return ANYADDR */
1129                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1130         return 0;
1131 }
1132 EXPORT_SYMBOL_GPL(rpc_localaddr);
1133
1134 void
1135 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1136 {
1137         struct rpc_xprt *xprt;
1138
1139         rcu_read_lock();
1140         xprt = rcu_dereference(clnt->cl_xprt);
1141         if (xprt->ops->set_buffer_size)
1142                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1143         rcu_read_unlock();
1144 }
1145 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1146
1147 /**
1148  * rpc_protocol - Get transport protocol number for an RPC client
1149  * @clnt: RPC client to query
1150  *
1151  */
1152 int rpc_protocol(struct rpc_clnt *clnt)
1153 {
1154         int protocol;
1155
1156         rcu_read_lock();
1157         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1158         rcu_read_unlock();
1159         return protocol;
1160 }
1161 EXPORT_SYMBOL_GPL(rpc_protocol);
1162
1163 /**
1164  * rpc_net_ns - Get the network namespace for this RPC client
1165  * @clnt: RPC client to query
1166  *
1167  */
1168 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1169 {
1170         struct net *ret;
1171
1172         rcu_read_lock();
1173         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1174         rcu_read_unlock();
1175         return ret;
1176 }
1177 EXPORT_SYMBOL_GPL(rpc_net_ns);
1178
1179 /**
1180  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1181  * @clnt: RPC client to query
1182  *
1183  * For stream transports, this is one RPC record fragment (see RFC
1184  * 1831), as we don't support multi-record requests yet.  For datagram
1185  * transports, this is the size of an IP packet minus the IP, UDP, and
1186  * RPC header sizes.
1187  */
1188 size_t rpc_max_payload(struct rpc_clnt *clnt)
1189 {
1190         size_t ret;
1191
1192         rcu_read_lock();
1193         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1194         rcu_read_unlock();
1195         return ret;
1196 }
1197 EXPORT_SYMBOL_GPL(rpc_max_payload);
1198
1199 /**
1200  * rpc_get_timeout - Get timeout for transport in units of HZ
1201  * @clnt: RPC client to query
1202  */
1203 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1204 {
1205         unsigned long ret;
1206
1207         rcu_read_lock();
1208         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1209         rcu_read_unlock();
1210         return ret;
1211 }
1212 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1213
1214 /**
1215  * rpc_force_rebind - force transport to check that remote port is unchanged
1216  * @clnt: client to rebind
1217  *
1218  */
1219 void rpc_force_rebind(struct rpc_clnt *clnt)
1220 {
1221         if (clnt->cl_autobind) {
1222                 rcu_read_lock();
1223                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1224                 rcu_read_unlock();
1225         }
1226 }
1227 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1228
1229 /*
1230  * Restart an (async) RPC call from the call_prepare state.
1231  * Usually called from within the exit handler.
1232  */
1233 int
1234 rpc_restart_call_prepare(struct rpc_task *task)
1235 {
1236         if (RPC_ASSASSINATED(task))
1237                 return 0;
1238         task->tk_action = call_start;
1239         if (task->tk_ops->rpc_call_prepare != NULL)
1240                 task->tk_action = rpc_prepare_task;
1241         return 1;
1242 }
1243 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1244
1245 /*
1246  * Restart an (async) RPC call. Usually called from within the
1247  * exit handler.
1248  */
1249 int
1250 rpc_restart_call(struct rpc_task *task)
1251 {
1252         if (RPC_ASSASSINATED(task))
1253                 return 0;
1254         task->tk_action = call_start;
1255         return 1;
1256 }
1257 EXPORT_SYMBOL_GPL(rpc_restart_call);
1258
1259 #ifdef RPC_DEBUG
1260 static const char *rpc_proc_name(const struct rpc_task *task)
1261 {
1262         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1263
1264         if (proc) {
1265                 if (proc->p_name)
1266                         return proc->p_name;
1267                 else
1268                         return "NULL";
1269         } else
1270                 return "no proc";
1271 }
1272 #endif
1273
1274 /*
1275  * 0.  Initial state
1276  *
1277  *     Other FSM states can be visited zero or more times, but
1278  *     this state is visited exactly once for each RPC.
1279  */
1280 static void
1281 call_start(struct rpc_task *task)
1282 {
1283         struct rpc_clnt *clnt = task->tk_client;
1284
1285         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1286                         clnt->cl_protname, clnt->cl_vers,
1287                         rpc_proc_name(task),
1288                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1289
1290         /* Increment call count */
1291         task->tk_msg.rpc_proc->p_count++;
1292         clnt->cl_stats->rpccnt++;
1293         task->tk_action = call_reserve;
1294 }
1295
1296 /*
1297  * 1.   Reserve an RPC call slot
1298  */
1299 static void
1300 call_reserve(struct rpc_task *task)
1301 {
1302         dprint_status(task);
1303
1304         task->tk_status  = 0;
1305         task->tk_action  = call_reserveresult;
1306         xprt_reserve(task);
1307 }
1308
1309 static void call_retry_reserve(struct rpc_task *task);
1310
1311 /*
1312  * 1b.  Grok the result of xprt_reserve()
1313  */
1314 static void
1315 call_reserveresult(struct rpc_task *task)
1316 {
1317         int status = task->tk_status;
1318
1319         dprint_status(task);
1320
1321         /*
1322          * After a call to xprt_reserve(), we must have either
1323          * a request slot or else an error status.
1324          */
1325         task->tk_status = 0;
1326         if (status >= 0) {
1327                 if (task->tk_rqstp) {
1328                         task->tk_action = call_refresh;
1329                         return;
1330                 }
1331
1332                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1333                                 __func__, status);
1334                 rpc_exit(task, -EIO);
1335                 return;
1336         }
1337
1338         /*
1339          * Even though there was an error, we may have acquired
1340          * a request slot somehow.  Make sure not to leak it.
1341          */
1342         if (task->tk_rqstp) {
1343                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1344                                 __func__, status);
1345                 xprt_release(task);
1346         }
1347
1348         switch (status) {
1349         case -ENOMEM:
1350                 rpc_delay(task, HZ >> 2);
1351         case -EAGAIN:   /* woken up; retry */
1352                 task->tk_action = call_retry_reserve;
1353                 return;
1354         case -EIO:      /* probably a shutdown */
1355                 break;
1356         default:
1357                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1358                                 __func__, status);
1359                 break;
1360         }
1361         rpc_exit(task, status);
1362 }
1363
1364 /*
1365  * 1c.  Retry reserving an RPC call slot
1366  */
1367 static void
1368 call_retry_reserve(struct rpc_task *task)
1369 {
1370         dprint_status(task);
1371
1372         task->tk_status  = 0;
1373         task->tk_action  = call_reserveresult;
1374         xprt_retry_reserve(task);
1375 }
1376
1377 /*
1378  * 2.   Bind and/or refresh the credentials
1379  */
1380 static void
1381 call_refresh(struct rpc_task *task)
1382 {
1383         dprint_status(task);
1384
1385         task->tk_action = call_refreshresult;
1386         task->tk_status = 0;
1387         task->tk_client->cl_stats->rpcauthrefresh++;
1388         rpcauth_refreshcred(task);
1389 }
1390
1391 /*
1392  * 2a.  Process the results of a credential refresh
1393  */
1394 static void
1395 call_refreshresult(struct rpc_task *task)
1396 {
1397         int status = task->tk_status;
1398
1399         dprint_status(task);
1400
1401         task->tk_status = 0;
1402         task->tk_action = call_refresh;
1403         switch (status) {
1404         case 0:
1405                 if (rpcauth_uptodatecred(task))
1406                         task->tk_action = call_allocate;
1407                 return;
1408         case -ETIMEDOUT:
1409                 rpc_delay(task, 3*HZ);
1410         case -EKEYEXPIRED:
1411         case -EAGAIN:
1412                 status = -EACCES;
1413                 if (!task->tk_cred_retry)
1414                         break;
1415                 task->tk_cred_retry--;
1416                 dprintk("RPC: %5u %s: retry refresh creds\n",
1417                                 task->tk_pid, __func__);
1418                 return;
1419         }
1420         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1421                                 task->tk_pid, __func__, status);
1422         rpc_exit(task, status);
1423 }
1424
1425 /*
1426  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1427  *      (Note: buffer memory is freed in xprt_release).
1428  */
1429 static void
1430 call_allocate(struct rpc_task *task)
1431 {
1432         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1433         struct rpc_rqst *req = task->tk_rqstp;
1434         struct rpc_xprt *xprt = req->rq_xprt;
1435         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1436
1437         dprint_status(task);
1438
1439         task->tk_status = 0;
1440         task->tk_action = call_bind;
1441
1442         if (req->rq_buffer)
1443                 return;
1444
1445         if (proc->p_proc != 0) {
1446                 BUG_ON(proc->p_arglen == 0);
1447                 if (proc->p_decode != NULL)
1448                         BUG_ON(proc->p_replen == 0);
1449         }
1450
1451         /*
1452          * Calculate the size (in quads) of the RPC call
1453          * and reply headers, and convert both values
1454          * to byte sizes.
1455          */
1456         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1457         req->rq_callsize <<= 2;
1458         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1459         req->rq_rcvsize <<= 2;
1460
1461         req->rq_buffer = xprt->ops->buf_alloc(task,
1462                                         req->rq_callsize + req->rq_rcvsize);
1463         if (req->rq_buffer != NULL)
1464                 return;
1465
1466         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1467
1468         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1469                 task->tk_action = call_allocate;
1470                 rpc_delay(task, HZ>>4);
1471                 return;
1472         }
1473
1474         rpc_exit(task, -ERESTARTSYS);
1475 }
1476
1477 static inline int
1478 rpc_task_need_encode(struct rpc_task *task)
1479 {
1480         return task->tk_rqstp->rq_snd_buf.len == 0;
1481 }
1482
1483 static inline void
1484 rpc_task_force_reencode(struct rpc_task *task)
1485 {
1486         task->tk_rqstp->rq_snd_buf.len = 0;
1487         task->tk_rqstp->rq_bytes_sent = 0;
1488 }
1489
1490 static inline void
1491 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1492 {
1493         buf->head[0].iov_base = start;
1494         buf->head[0].iov_len = len;
1495         buf->tail[0].iov_len = 0;
1496         buf->page_len = 0;
1497         buf->flags = 0;
1498         buf->len = 0;
1499         buf->buflen = len;
1500 }
1501
1502 /*
1503  * 3.   Encode arguments of an RPC call
1504  */
1505 static void
1506 rpc_xdr_encode(struct rpc_task *task)
1507 {
1508         struct rpc_rqst *req = task->tk_rqstp;
1509         kxdreproc_t     encode;
1510         __be32          *p;
1511
1512         dprint_status(task);
1513
1514         rpc_xdr_buf_init(&req->rq_snd_buf,
1515                          req->rq_buffer,
1516                          req->rq_callsize);
1517         rpc_xdr_buf_init(&req->rq_rcv_buf,
1518                          (char *)req->rq_buffer + req->rq_callsize,
1519                          req->rq_rcvsize);
1520
1521         p = rpc_encode_header(task);
1522         if (p == NULL) {
1523                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1524                 rpc_exit(task, -EIO);
1525                 return;
1526         }
1527
1528         encode = task->tk_msg.rpc_proc->p_encode;
1529         if (encode == NULL)
1530                 return;
1531
1532         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1533                         task->tk_msg.rpc_argp);
1534 }
1535
1536 /*
1537  * 4.   Get the server port number if not yet set
1538  */
1539 static void
1540 call_bind(struct rpc_task *task)
1541 {
1542         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1543
1544         dprint_status(task);
1545
1546         task->tk_action = call_connect;
1547         if (!xprt_bound(xprt)) {
1548                 task->tk_action = call_bind_status;
1549                 task->tk_timeout = xprt->bind_timeout;
1550                 xprt->ops->rpcbind(task);
1551         }
1552 }
1553
1554 /*
1555  * 4a.  Sort out bind result
1556  */
1557 static void
1558 call_bind_status(struct rpc_task *task)
1559 {
1560         int status = -EIO;
1561
1562         if (task->tk_status >= 0) {
1563                 dprint_status(task);
1564                 task->tk_status = 0;
1565                 task->tk_action = call_connect;
1566                 return;
1567         }
1568
1569         trace_rpc_bind_status(task);
1570         switch (task->tk_status) {
1571         case -ENOMEM:
1572                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1573                 rpc_delay(task, HZ >> 2);
1574                 goto retry_timeout;
1575         case -EACCES:
1576                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1577                                 "unavailable\n", task->tk_pid);
1578                 /* fail immediately if this is an RPC ping */
1579                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1580                         status = -EOPNOTSUPP;
1581                         break;
1582                 }
1583                 if (task->tk_rebind_retry == 0)
1584                         break;
1585                 task->tk_rebind_retry--;
1586                 rpc_delay(task, 3*HZ);
1587                 goto retry_timeout;
1588         case -ETIMEDOUT:
1589                 dprintk("RPC: %5u rpcbind request timed out\n",
1590                                 task->tk_pid);
1591                 goto retry_timeout;
1592         case -EPFNOSUPPORT:
1593                 /* server doesn't support any rpcbind version we know of */
1594                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1595                                 task->tk_pid);
1596                 break;
1597         case -EPROTONOSUPPORT:
1598                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1599                                 task->tk_pid);
1600                 task->tk_status = 0;
1601                 task->tk_action = call_bind;
1602                 return;
1603         case -ECONNREFUSED:             /* connection problems */
1604         case -ECONNRESET:
1605         case -ENOTCONN:
1606         case -EHOSTDOWN:
1607         case -EHOSTUNREACH:
1608         case -ENETUNREACH:
1609         case -EPIPE:
1610                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1611                                 task->tk_pid, task->tk_status);
1612                 if (!RPC_IS_SOFTCONN(task)) {
1613                         rpc_delay(task, 5*HZ);
1614                         goto retry_timeout;
1615                 }
1616                 status = task->tk_status;
1617                 break;
1618         default:
1619                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1620                                 task->tk_pid, -task->tk_status);
1621         }
1622
1623         rpc_exit(task, status);
1624         return;
1625
1626 retry_timeout:
1627         task->tk_action = call_timeout;
1628 }
1629
1630 /*
1631  * 4b.  Connect to the RPC server
1632  */
1633 static void
1634 call_connect(struct rpc_task *task)
1635 {
1636         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1637
1638         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1639                         task->tk_pid, xprt,
1640                         (xprt_connected(xprt) ? "is" : "is not"));
1641
1642         task->tk_action = call_transmit;
1643         if (!xprt_connected(xprt)) {
1644                 task->tk_action = call_connect_status;
1645                 if (task->tk_status < 0)
1646                         return;
1647                 xprt_connect(task);
1648         }
1649 }
1650
1651 /*
1652  * 4c.  Sort out connect result
1653  */
1654 static void
1655 call_connect_status(struct rpc_task *task)
1656 {
1657         struct rpc_clnt *clnt = task->tk_client;
1658         int status = task->tk_status;
1659
1660         dprint_status(task);
1661
1662         trace_rpc_connect_status(task, status);
1663         switch (status) {
1664                 /* if soft mounted, test if we've timed out */
1665         case -ETIMEDOUT:
1666                 task->tk_action = call_timeout;
1667                 return;
1668         case -ECONNREFUSED:
1669         case -ECONNRESET:
1670         case -ENETUNREACH:
1671                 if (RPC_IS_SOFTCONN(task))
1672                         break;
1673                 /* retry with existing socket, after a delay */
1674         case 0:
1675         case -EAGAIN:
1676                 task->tk_status = 0;
1677                 clnt->cl_stats->netreconn++;
1678                 task->tk_action = call_transmit;
1679                 return;
1680         }
1681         rpc_exit(task, status);
1682 }
1683
1684 /*
1685  * 5.   Transmit the RPC request, and wait for reply
1686  */
1687 static void
1688 call_transmit(struct rpc_task *task)
1689 {
1690         dprint_status(task);
1691
1692         task->tk_action = call_status;
1693         if (task->tk_status < 0)
1694                 return;
1695         task->tk_status = xprt_prepare_transmit(task);
1696         if (task->tk_status != 0)
1697                 return;
1698         task->tk_action = call_transmit_status;
1699         /* Encode here so that rpcsec_gss can use correct sequence number. */
1700         if (rpc_task_need_encode(task)) {
1701                 rpc_xdr_encode(task);
1702                 /* Did the encode result in an error condition? */
1703                 if (task->tk_status != 0) {
1704                         /* Was the error nonfatal? */
1705                         if (task->tk_status == -EAGAIN)
1706                                 rpc_delay(task, HZ >> 4);
1707                         else
1708                                 rpc_exit(task, task->tk_status);
1709                         return;
1710                 }
1711         }
1712         xprt_transmit(task);
1713         if (task->tk_status < 0)
1714                 return;
1715         /*
1716          * On success, ensure that we call xprt_end_transmit() before sleeping
1717          * in order to allow access to the socket to other RPC requests.
1718          */
1719         call_transmit_status(task);
1720         if (rpc_reply_expected(task))
1721                 return;
1722         task->tk_action = rpc_exit_task;
1723         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1724 }
1725
1726 /*
1727  * 5a.  Handle cleanup after a transmission
1728  */
1729 static void
1730 call_transmit_status(struct rpc_task *task)
1731 {
1732         task->tk_action = call_status;
1733
1734         /*
1735          * Common case: success.  Force the compiler to put this
1736          * test first.
1737          */
1738         if (task->tk_status == 0) {
1739                 xprt_end_transmit(task);
1740                 rpc_task_force_reencode(task);
1741                 return;
1742         }
1743
1744         switch (task->tk_status) {
1745         case -EAGAIN:
1746                 break;
1747         default:
1748                 dprint_status(task);
1749                 xprt_end_transmit(task);
1750                 rpc_task_force_reencode(task);
1751                 break;
1752                 /*
1753                  * Special cases: if we've been waiting on the
1754                  * socket's write_space() callback, or if the
1755                  * socket just returned a connection error,
1756                  * then hold onto the transport lock.
1757                  */
1758         case -ECONNREFUSED:
1759         case -EHOSTDOWN:
1760         case -EHOSTUNREACH:
1761         case -ENETUNREACH:
1762                 if (RPC_IS_SOFTCONN(task)) {
1763                         xprt_end_transmit(task);
1764                         rpc_exit(task, task->tk_status);
1765                         break;
1766                 }
1767         case -ECONNRESET:
1768         case -ENOTCONN:
1769         case -EPIPE:
1770                 rpc_task_force_reencode(task);
1771         }
1772 }
1773
1774 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1775 /*
1776  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1777  * addition, disconnect on connectivity errors.
1778  */
1779 static void
1780 call_bc_transmit(struct rpc_task *task)
1781 {
1782         struct rpc_rqst *req = task->tk_rqstp;
1783
1784         task->tk_status = xprt_prepare_transmit(task);
1785         if (task->tk_status == -EAGAIN) {
1786                 /*
1787                  * Could not reserve the transport. Try again after the
1788                  * transport is released.
1789                  */
1790                 task->tk_status = 0;
1791                 task->tk_action = call_bc_transmit;
1792                 return;
1793         }
1794
1795         task->tk_action = rpc_exit_task;
1796         if (task->tk_status < 0) {
1797                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1798                         "error: %d\n", task->tk_status);
1799                 return;
1800         }
1801
1802         xprt_transmit(task);
1803         xprt_end_transmit(task);
1804         dprint_status(task);
1805         switch (task->tk_status) {
1806         case 0:
1807                 /* Success */
1808                 break;
1809         case -EHOSTDOWN:
1810         case -EHOSTUNREACH:
1811         case -ENETUNREACH:
1812         case -ETIMEDOUT:
1813                 /*
1814                  * Problem reaching the server.  Disconnect and let the
1815                  * forechannel reestablish the connection.  The server will
1816                  * have to retransmit the backchannel request and we'll
1817                  * reprocess it.  Since these ops are idempotent, there's no
1818                  * need to cache our reply at this time.
1819                  */
1820                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1821                         "error: %d\n", task->tk_status);
1822                 xprt_conditional_disconnect(req->rq_xprt,
1823                         req->rq_connect_cookie);
1824                 break;
1825         default:
1826                 /*
1827                  * We were unable to reply and will have to drop the
1828                  * request.  The server should reconnect and retransmit.
1829                  */
1830                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
1831                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1832                         "error: %d\n", task->tk_status);
1833                 break;
1834         }
1835         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1836 }
1837 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1838
1839 /*
1840  * 6.   Sort out the RPC call status
1841  */
1842 static void
1843 call_status(struct rpc_task *task)
1844 {
1845         struct rpc_clnt *clnt = task->tk_client;
1846         struct rpc_rqst *req = task->tk_rqstp;
1847         int             status;
1848
1849         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1850                 task->tk_status = req->rq_reply_bytes_recvd;
1851
1852         dprint_status(task);
1853
1854         status = task->tk_status;
1855         if (status >= 0) {
1856                 task->tk_action = call_decode;
1857                 return;
1858         }
1859
1860         trace_rpc_call_status(task);
1861         task->tk_status = 0;
1862         switch(status) {
1863         case -EHOSTDOWN:
1864         case -EHOSTUNREACH:
1865         case -ENETUNREACH:
1866                 /*
1867                  * Delay any retries for 3 seconds, then handle as if it
1868                  * were a timeout.
1869                  */
1870                 rpc_delay(task, 3*HZ);
1871         case -ETIMEDOUT:
1872                 task->tk_action = call_timeout;
1873                 if (task->tk_client->cl_discrtry)
1874                         xprt_conditional_disconnect(req->rq_xprt,
1875                                         req->rq_connect_cookie);
1876                 break;
1877         case -ECONNRESET:
1878         case -ECONNREFUSED:
1879                 rpc_force_rebind(clnt);
1880                 rpc_delay(task, 3*HZ);
1881         case -EPIPE:
1882         case -ENOTCONN:
1883                 task->tk_action = call_bind;
1884                 break;
1885         case -EAGAIN:
1886                 task->tk_action = call_transmit;
1887                 break;
1888         case -EIO:
1889                 /* shutdown or soft timeout */
1890                 rpc_exit(task, status);
1891                 break;
1892         default:
1893                 if (clnt->cl_chatty)
1894                         printk("%s: RPC call returned error %d\n",
1895                                clnt->cl_protname, -status);
1896                 rpc_exit(task, status);
1897         }
1898 }
1899
1900 /*
1901  * 6a.  Handle RPC timeout
1902  *      We do not release the request slot, so we keep using the
1903  *      same XID for all retransmits.
1904  */
1905 static void
1906 call_timeout(struct rpc_task *task)
1907 {
1908         struct rpc_clnt *clnt = task->tk_client;
1909
1910         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1911                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1912                 goto retry;
1913         }
1914
1915         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1916         task->tk_timeouts++;
1917
1918         if (RPC_IS_SOFTCONN(task)) {
1919                 rpc_exit(task, -ETIMEDOUT);
1920                 return;
1921         }
1922         if (RPC_IS_SOFT(task)) {
1923                 if (clnt->cl_chatty) {
1924                         rcu_read_lock();
1925                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1926                                 clnt->cl_protname,
1927                                 rcu_dereference(clnt->cl_xprt)->servername);
1928                         rcu_read_unlock();
1929                 }
1930                 if (task->tk_flags & RPC_TASK_TIMEOUT)
1931                         rpc_exit(task, -ETIMEDOUT);
1932                 else
1933                         rpc_exit(task, -EIO);
1934                 return;
1935         }
1936
1937         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1938                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1939                 if (clnt->cl_chatty) {
1940                         rcu_read_lock();
1941                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1942                         clnt->cl_protname,
1943                         rcu_dereference(clnt->cl_xprt)->servername);
1944                         rcu_read_unlock();
1945                 }
1946         }
1947         rpc_force_rebind(clnt);
1948         /*
1949          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1950          * event? RFC2203 requires the server to drop all such requests.
1951          */
1952         rpcauth_invalcred(task);
1953
1954 retry:
1955         clnt->cl_stats->rpcretrans++;
1956         task->tk_action = call_bind;
1957         task->tk_status = 0;
1958 }
1959
1960 /*
1961  * 7.   Decode the RPC reply
1962  */
1963 static void
1964 call_decode(struct rpc_task *task)
1965 {
1966         struct rpc_clnt *clnt = task->tk_client;
1967         struct rpc_rqst *req = task->tk_rqstp;
1968         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
1969         __be32          *p;
1970
1971         dprint_status(task);
1972
1973         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1974                 if (clnt->cl_chatty) {
1975                         rcu_read_lock();
1976                         printk(KERN_NOTICE "%s: server %s OK\n",
1977                                 clnt->cl_protname,
1978                                 rcu_dereference(clnt->cl_xprt)->servername);
1979                         rcu_read_unlock();
1980                 }
1981                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1982         }
1983
1984         /*
1985          * Ensure that we see all writes made by xprt_complete_rqst()
1986          * before it changed req->rq_reply_bytes_recvd.
1987          */
1988         smp_rmb();
1989         req->rq_rcv_buf.len = req->rq_private_buf.len;
1990
1991         /* Check that the softirq receive buffer is valid */
1992         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1993                                 sizeof(req->rq_rcv_buf)) != 0);
1994
1995         if (req->rq_rcv_buf.len < 12) {
1996                 if (!RPC_IS_SOFT(task)) {
1997                         task->tk_action = call_bind;
1998                         clnt->cl_stats->rpcretrans++;
1999                         goto out_retry;
2000                 }
2001                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2002                                 clnt->cl_protname, task->tk_status);
2003                 task->tk_action = call_timeout;
2004                 goto out_retry;
2005         }
2006
2007         p = rpc_verify_header(task);
2008         if (IS_ERR(p)) {
2009                 if (p == ERR_PTR(-EAGAIN))
2010                         goto out_retry;
2011                 return;
2012         }
2013
2014         task->tk_action = rpc_exit_task;
2015
2016         if (decode) {
2017                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2018                                                       task->tk_msg.rpc_resp);
2019         }
2020         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2021                         task->tk_status);
2022         return;
2023 out_retry:
2024         task->tk_status = 0;
2025         /* Note: rpc_verify_header() may have freed the RPC slot */
2026         if (task->tk_rqstp == req) {
2027                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2028                 if (task->tk_client->cl_discrtry)
2029                         xprt_conditional_disconnect(req->rq_xprt,
2030                                         req->rq_connect_cookie);
2031         }
2032 }
2033
2034 static __be32 *
2035 rpc_encode_header(struct rpc_task *task)
2036 {
2037         struct rpc_clnt *clnt = task->tk_client;
2038         struct rpc_rqst *req = task->tk_rqstp;
2039         __be32          *p = req->rq_svec[0].iov_base;
2040
2041         /* FIXME: check buffer size? */
2042
2043         p = xprt_skip_transport_header(req->rq_xprt, p);
2044         *p++ = req->rq_xid;             /* XID */
2045         *p++ = htonl(RPC_CALL);         /* CALL */
2046         *p++ = htonl(RPC_VERSION);      /* RPC version */
2047         *p++ = htonl(clnt->cl_prog);    /* program number */
2048         *p++ = htonl(clnt->cl_vers);    /* program version */
2049         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2050         p = rpcauth_marshcred(task, p);
2051         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2052         return p;
2053 }
2054
2055 static __be32 *
2056 rpc_verify_header(struct rpc_task *task)
2057 {
2058         struct rpc_clnt *clnt = task->tk_client;
2059         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2060         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2061         __be32  *p = iov->iov_base;
2062         u32 n;
2063         int error = -EACCES;
2064
2065         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2066                 /* RFC-1014 says that the representation of XDR data must be a
2067                  * multiple of four bytes
2068                  * - if it isn't pointer subtraction in the NFS client may give
2069                  *   undefined results
2070                  */
2071                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2072                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2073                        task->tk_rqstp->rq_rcv_buf.len);
2074                 goto out_eio;
2075         }
2076         if ((len -= 3) < 0)
2077                 goto out_overflow;
2078
2079         p += 1; /* skip XID */
2080         if ((n = ntohl(*p++)) != RPC_REPLY) {
2081                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2082                         task->tk_pid, __func__, n);
2083                 goto out_garbage;
2084         }
2085
2086         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2087                 if (--len < 0)
2088                         goto out_overflow;
2089                 switch ((n = ntohl(*p++))) {
2090                 case RPC_AUTH_ERROR:
2091                         break;
2092                 case RPC_MISMATCH:
2093                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2094                                 task->tk_pid, __func__);
2095                         error = -EPROTONOSUPPORT;
2096                         goto out_err;
2097                 default:
2098                         dprintk("RPC: %5u %s: RPC call rejected, "
2099                                 "unknown error: %x\n",
2100                                 task->tk_pid, __func__, n);
2101                         goto out_eio;
2102                 }
2103                 if (--len < 0)
2104                         goto out_overflow;
2105                 switch ((n = ntohl(*p++))) {
2106                 case RPC_AUTH_REJECTEDCRED:
2107                 case RPC_AUTH_REJECTEDVERF:
2108                 case RPCSEC_GSS_CREDPROBLEM:
2109                 case RPCSEC_GSS_CTXPROBLEM:
2110                         if (!task->tk_cred_retry)
2111                                 break;
2112                         task->tk_cred_retry--;
2113                         dprintk("RPC: %5u %s: retry stale creds\n",
2114                                         task->tk_pid, __func__);
2115                         rpcauth_invalcred(task);
2116                         /* Ensure we obtain a new XID! */
2117                         xprt_release(task);
2118                         task->tk_action = call_reserve;
2119                         goto out_retry;
2120                 case RPC_AUTH_BADCRED:
2121                 case RPC_AUTH_BADVERF:
2122                         /* possibly garbled cred/verf? */
2123                         if (!task->tk_garb_retry)
2124                                 break;
2125                         task->tk_garb_retry--;
2126                         dprintk("RPC: %5u %s: retry garbled creds\n",
2127                                         task->tk_pid, __func__);
2128                         task->tk_action = call_bind;
2129                         goto out_retry;
2130                 case RPC_AUTH_TOOWEAK:
2131                         rcu_read_lock();
2132                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2133                                "authentication.\n",
2134                                rcu_dereference(clnt->cl_xprt)->servername);
2135                         rcu_read_unlock();
2136                         break;
2137                 default:
2138                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2139                                         task->tk_pid, __func__, n);
2140                         error = -EIO;
2141                 }
2142                 dprintk("RPC: %5u %s: call rejected %d\n",
2143                                 task->tk_pid, __func__, n);
2144                 goto out_err;
2145         }
2146         if (!(p = rpcauth_checkverf(task, p))) {
2147                 dprintk("RPC: %5u %s: auth check failed\n",
2148                                 task->tk_pid, __func__);
2149                 goto out_garbage;               /* bad verifier, retry */
2150         }
2151         len = p - (__be32 *)iov->iov_base - 1;
2152         if (len < 0)
2153                 goto out_overflow;
2154         switch ((n = ntohl(*p++))) {
2155         case RPC_SUCCESS:
2156                 return p;
2157         case RPC_PROG_UNAVAIL:
2158                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2159                                 "by server %s\n", task->tk_pid, __func__,
2160                                 (unsigned int)clnt->cl_prog,
2161                                 rcu_dereference(clnt->cl_xprt)->servername);
2162                 error = -EPFNOSUPPORT;
2163                 goto out_err;
2164         case RPC_PROG_MISMATCH:
2165                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2166                                 "by server %s\n", task->tk_pid, __func__,
2167                                 (unsigned int)clnt->cl_prog,
2168                                 (unsigned int)clnt->cl_vers,
2169                                 rcu_dereference(clnt->cl_xprt)->servername);
2170                 error = -EPROTONOSUPPORT;
2171                 goto out_err;
2172         case RPC_PROC_UNAVAIL:
2173                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2174                                 "version %u on server %s\n",
2175                                 task->tk_pid, __func__,
2176                                 rpc_proc_name(task),
2177                                 clnt->cl_prog, clnt->cl_vers,
2178                                 rcu_dereference(clnt->cl_xprt)->servername);
2179                 error = -EOPNOTSUPP;
2180                 goto out_err;
2181         case RPC_GARBAGE_ARGS:
2182                 dprintk("RPC: %5u %s: server saw garbage\n",
2183                                 task->tk_pid, __func__);
2184                 break;                  /* retry */
2185         default:
2186                 dprintk("RPC: %5u %s: server accept status: %x\n",
2187                                 task->tk_pid, __func__, n);
2188                 /* Also retry */
2189         }
2190
2191 out_garbage:
2192         clnt->cl_stats->rpcgarbage++;
2193         if (task->tk_garb_retry) {
2194                 task->tk_garb_retry--;
2195                 dprintk("RPC: %5u %s: retrying\n",
2196                                 task->tk_pid, __func__);
2197                 task->tk_action = call_bind;
2198 out_retry:
2199                 return ERR_PTR(-EAGAIN);
2200         }
2201 out_eio:
2202         error = -EIO;
2203 out_err:
2204         rpc_exit(task, error);
2205         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2206                         __func__, error);
2207         return ERR_PTR(error);
2208 out_overflow:
2209         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2210                         __func__);
2211         goto out_garbage;
2212 }
2213
2214 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2215 {
2216 }
2217
2218 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2219 {
2220         return 0;
2221 }
2222
2223 static struct rpc_procinfo rpcproc_null = {
2224         .p_encode = rpcproc_encode_null,
2225         .p_decode = rpcproc_decode_null,
2226 };
2227
2228 static int rpc_ping(struct rpc_clnt *clnt)
2229 {
2230         struct rpc_message msg = {
2231                 .rpc_proc = &rpcproc_null,
2232         };
2233         int err;
2234         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2235         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2236         put_rpccred(msg.rpc_cred);
2237         return err;
2238 }
2239
2240 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2241 {
2242         struct rpc_message msg = {
2243                 .rpc_proc = &rpcproc_null,
2244                 .rpc_cred = cred,
2245         };
2246         struct rpc_task_setup task_setup_data = {
2247                 .rpc_client = clnt,
2248                 .rpc_message = &msg,
2249                 .callback_ops = &rpc_default_ops,
2250                 .flags = flags,
2251         };
2252         return rpc_run_task(&task_setup_data);
2253 }
2254 EXPORT_SYMBOL_GPL(rpc_call_null);
2255
2256 #ifdef RPC_DEBUG
2257 static void rpc_show_header(void)
2258 {
2259         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2260                 "-timeout ---ops--\n");
2261 }
2262
2263 static void rpc_show_task(const struct rpc_clnt *clnt,
2264                           const struct rpc_task *task)
2265 {
2266         const char *rpc_waitq = "none";
2267
2268         if (RPC_IS_QUEUED(task))
2269                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2270
2271         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2272                 task->tk_pid, task->tk_flags, task->tk_status,
2273                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2274                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
2275                 task->tk_action, rpc_waitq);
2276 }
2277
2278 void rpc_show_tasks(struct net *net)
2279 {
2280         struct rpc_clnt *clnt;
2281         struct rpc_task *task;
2282         int header = 0;
2283         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2284
2285         spin_lock(&sn->rpc_client_lock);
2286         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2287                 spin_lock(&clnt->cl_lock);
2288                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2289                         if (!header) {
2290                                 rpc_show_header();
2291                                 header++;
2292                         }
2293                         rpc_show_task(clnt, task);
2294                 }
2295                 spin_unlock(&clnt->cl_lock);
2296         }
2297         spin_unlock(&sn->rpc_client_lock);
2298 }
2299 #endif