90e82c5daeb6fecda5998a6d2b5f785e2db9731c
[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 #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 #include "netns.h"
42
43 #ifdef RPC_DEBUG
44 # define RPCDBG_FACILITY        RPCDBG_CALL
45 #endif
46
47 #define dprint_status(t)                                        \
48         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
49                         __func__, t->tk_status)
50
51 /*
52  * All RPC clients are linked into this list
53  */
54
55 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
56
57
58 static void     call_start(struct rpc_task *task);
59 static void     call_reserve(struct rpc_task *task);
60 static void     call_reserveresult(struct rpc_task *task);
61 static void     call_allocate(struct rpc_task *task);
62 static void     call_decode(struct rpc_task *task);
63 static void     call_bind(struct rpc_task *task);
64 static void     call_bind_status(struct rpc_task *task);
65 static void     call_transmit(struct rpc_task *task);
66 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
67 static void     call_bc_transmit(struct rpc_task *task);
68 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
69 static void     call_status(struct rpc_task *task);
70 static void     call_transmit_status(struct rpc_task *task);
71 static void     call_refresh(struct rpc_task *task);
72 static void     call_refreshresult(struct rpc_task *task);
73 static void     call_timeout(struct rpc_task *task);
74 static void     call_connect(struct rpc_task *task);
75 static void     call_connect_status(struct rpc_task *task);
76
77 static __be32   *rpc_encode_header(struct rpc_task *task);
78 static __be32   *rpc_verify_header(struct rpc_task *task);
79 static int      rpc_ping(struct rpc_clnt *clnt);
80
81 static void rpc_register_client(struct rpc_clnt *clnt)
82 {
83         struct sunrpc_net *sn = net_generic(clnt->cl_xprt->xprt_net, sunrpc_net_id);
84
85         spin_lock(&sn->rpc_client_lock);
86         list_add(&clnt->cl_clients, &sn->all_clients);
87         spin_unlock(&sn->rpc_client_lock);
88 }
89
90 static void rpc_unregister_client(struct rpc_clnt *clnt)
91 {
92         struct sunrpc_net *sn = net_generic(clnt->cl_xprt->xprt_net, sunrpc_net_id);
93
94         spin_lock(&sn->rpc_client_lock);
95         list_del(&clnt->cl_clients);
96         spin_unlock(&sn->rpc_client_lock);
97 }
98
99 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
100 {
101         if (clnt->cl_path.dentry)
102                 rpc_remove_client_dir(clnt->cl_path.dentry);
103         clnt->cl_path.dentry = NULL;
104 }
105
106 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
107 {
108         struct super_block *pipefs_sb;
109         int put_mnt = 0;
110
111         pipefs_sb = rpc_get_sb_net(clnt->cl_xprt->xprt_net);
112         if (pipefs_sb) {
113                 if (clnt->cl_path.dentry)
114                         put_mnt = 1;
115                 __rpc_clnt_remove_pipedir(clnt);
116                 rpc_put_sb_net(clnt->cl_xprt->xprt_net);
117         }
118         if (put_mnt)
119                 rpc_put_mount();
120 }
121
122 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
123                                     struct rpc_clnt *clnt, char *dir_name)
124 {
125         static uint32_t clntid;
126         char name[15];
127         struct qstr q = {
128                 .name = name,
129         };
130         struct dentry *dir, *dentry;
131         int error;
132
133         dir = rpc_d_lookup_sb(sb, dir_name);
134         if (dir == NULL)
135                 return dir;
136         for (;;) {
137                 q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
138                 name[sizeof(name) - 1] = '\0';
139                 q.hash = full_name_hash(q.name, q.len);
140                 dentry = rpc_create_client_dir(dir, &q, clnt);
141                 if (!IS_ERR(dentry))
142                         break;
143                 error = PTR_ERR(dentry);
144                 if (error != -EEXIST) {
145                         printk(KERN_INFO "RPC: Couldn't create pipefs entry"
146                                         " %s/%s, error %d\n",
147                                         dir_name, name, error);
148                         break;
149                 }
150         }
151         dput(dir);
152         return dentry;
153 }
154
155 static int
156 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
157 {
158         struct super_block *pipefs_sb;
159         struct path path;
160
161         clnt->cl_path.mnt = ERR_PTR(-ENOENT);
162         clnt->cl_path.dentry = NULL;
163         if (dir_name == NULL)
164                 return 0;
165
166         path.mnt = rpc_get_mount();
167         if (IS_ERR(path.mnt))
168                 return PTR_ERR(path.mnt);
169         pipefs_sb = rpc_get_sb_net(clnt->cl_xprt->xprt_net);
170         if (!pipefs_sb) {
171                 rpc_put_mount();
172                 return -ENOENT;
173         }
174         path.dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt, dir_name);
175         rpc_put_sb_net(clnt->cl_xprt->xprt_net);
176         if (IS_ERR(path.dentry)) {
177                 rpc_put_mount();
178                 return PTR_ERR(path.dentry);
179         }
180         clnt->cl_path = path;
181         return 0;
182 }
183
184 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
185 {
186         struct rpc_program      *program = args->program;
187         struct rpc_version      *version;
188         struct rpc_clnt         *clnt = NULL;
189         struct rpc_auth         *auth;
190         int err;
191         size_t len;
192
193         /* sanity check the name before trying to print it */
194         err = -EINVAL;
195         len = strlen(args->servername);
196         if (len > RPC_MAXNETNAMELEN)
197                 goto out_no_rpciod;
198         len++;
199
200         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
201                         program->name, args->servername, xprt);
202
203         err = rpciod_up();
204         if (err)
205                 goto out_no_rpciod;
206         err = -EINVAL;
207         if (!xprt)
208                 goto out_no_xprt;
209
210         if (args->version >= program->nrvers)
211                 goto out_err;
212         version = program->version[args->version];
213         if (version == NULL)
214                 goto out_err;
215
216         err = -ENOMEM;
217         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
218         if (!clnt)
219                 goto out_err;
220         clnt->cl_parent = clnt;
221
222         clnt->cl_server = clnt->cl_inline_name;
223         if (len > sizeof(clnt->cl_inline_name)) {
224                 char *buf = kmalloc(len, GFP_KERNEL);
225                 if (buf != NULL)
226                         clnt->cl_server = buf;
227                 else
228                         len = sizeof(clnt->cl_inline_name);
229         }
230         strlcpy(clnt->cl_server, args->servername, len);
231
232         clnt->cl_xprt     = xprt;
233         clnt->cl_procinfo = version->procs;
234         clnt->cl_maxproc  = version->nrprocs;
235         clnt->cl_protname = program->name;
236         clnt->cl_prog     = args->prognumber ? : program->number;
237         clnt->cl_vers     = version->number;
238         clnt->cl_stats    = program->stats;
239         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
240         err = -ENOMEM;
241         if (clnt->cl_metrics == NULL)
242                 goto out_no_stats;
243         clnt->cl_program  = program;
244         INIT_LIST_HEAD(&clnt->cl_tasks);
245         spin_lock_init(&clnt->cl_lock);
246
247         if (!xprt_bound(clnt->cl_xprt))
248                 clnt->cl_autobind = 1;
249
250         clnt->cl_timeout = xprt->timeout;
251         if (args->timeout != NULL) {
252                 memcpy(&clnt->cl_timeout_default, args->timeout,
253                                 sizeof(clnt->cl_timeout_default));
254                 clnt->cl_timeout = &clnt->cl_timeout_default;
255         }
256
257         clnt->cl_rtt = &clnt->cl_rtt_default;
258         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
259         clnt->cl_principal = NULL;
260         if (args->client_name) {
261                 clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
262                 if (!clnt->cl_principal)
263                         goto out_no_principal;
264         }
265
266         atomic_set(&clnt->cl_count, 1);
267
268         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
269         if (err < 0)
270                 goto out_no_path;
271
272         auth = rpcauth_create(args->authflavor, clnt);
273         if (IS_ERR(auth)) {
274                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
275                                 args->authflavor);
276                 err = PTR_ERR(auth);
277                 goto out_no_auth;
278         }
279
280         /* save the nodename */
281         clnt->cl_nodelen = strlen(init_utsname()->nodename);
282         if (clnt->cl_nodelen > UNX_MAXNODENAME)
283                 clnt->cl_nodelen = UNX_MAXNODENAME;
284         memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen);
285         rpc_register_client(clnt);
286         return clnt;
287
288 out_no_auth:
289         rpc_clnt_remove_pipedir(clnt);
290 out_no_path:
291         kfree(clnt->cl_principal);
292 out_no_principal:
293         rpc_free_iostats(clnt->cl_metrics);
294 out_no_stats:
295         if (clnt->cl_server != clnt->cl_inline_name)
296                 kfree(clnt->cl_server);
297         kfree(clnt);
298 out_err:
299         xprt_put(xprt);
300 out_no_xprt:
301         rpciod_down();
302 out_no_rpciod:
303         return ERR_PTR(err);
304 }
305
306 /*
307  * rpc_create - create an RPC client and transport with one call
308  * @args: rpc_clnt create argument structure
309  *
310  * Creates and initializes an RPC transport and an RPC client.
311  *
312  * It can ping the server in order to determine if it is up, and to see if
313  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
314  * this behavior so asynchronous tasks can also use rpc_create.
315  */
316 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
317 {
318         struct rpc_xprt *xprt;
319         struct rpc_clnt *clnt;
320         struct xprt_create xprtargs = {
321                 .net = args->net,
322                 .ident = args->protocol,
323                 .srcaddr = args->saddress,
324                 .dstaddr = args->address,
325                 .addrlen = args->addrsize,
326                 .bc_xprt = args->bc_xprt,
327         };
328         char servername[48];
329
330         /*
331          * If the caller chooses not to specify a hostname, whip
332          * up a string representation of the passed-in address.
333          */
334         if (args->servername == NULL) {
335                 struct sockaddr_un *sun =
336                                 (struct sockaddr_un *)args->address;
337                 struct sockaddr_in *sin =
338                                 (struct sockaddr_in *)args->address;
339                 struct sockaddr_in6 *sin6 =
340                                 (struct sockaddr_in6 *)args->address;
341
342                 servername[0] = '\0';
343                 switch (args->address->sa_family) {
344                 case AF_LOCAL:
345                         snprintf(servername, sizeof(servername), "%s",
346                                  sun->sun_path);
347                         break;
348                 case AF_INET:
349                         snprintf(servername, sizeof(servername), "%pI4",
350                                  &sin->sin_addr.s_addr);
351                         break;
352                 case AF_INET6:
353                         snprintf(servername, sizeof(servername), "%pI6",
354                                  &sin6->sin6_addr);
355                         break;
356                 default:
357                         /* caller wants default server name, but
358                          * address family isn't recognized. */
359                         return ERR_PTR(-EINVAL);
360                 }
361                 args->servername = servername;
362         }
363
364         xprt = xprt_create_transport(&xprtargs);
365         if (IS_ERR(xprt))
366                 return (struct rpc_clnt *)xprt;
367
368         /*
369          * By default, kernel RPC client connects from a reserved port.
370          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
371          * but it is always enabled for rpciod, which handles the connect
372          * operation.
373          */
374         xprt->resvport = 1;
375         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
376                 xprt->resvport = 0;
377
378         clnt = rpc_new_client(args, xprt);
379         if (IS_ERR(clnt))
380                 return clnt;
381
382         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
383                 int err = rpc_ping(clnt);
384                 if (err != 0) {
385                         rpc_shutdown_client(clnt);
386                         return ERR_PTR(err);
387                 }
388         }
389
390         clnt->cl_softrtry = 1;
391         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
392                 clnt->cl_softrtry = 0;
393
394         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
395                 clnt->cl_autobind = 1;
396         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
397                 clnt->cl_discrtry = 1;
398         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
399                 clnt->cl_chatty = 1;
400
401         return clnt;
402 }
403 EXPORT_SYMBOL_GPL(rpc_create);
404
405 /*
406  * This function clones the RPC client structure. It allows us to share the
407  * same transport while varying parameters such as the authentication
408  * flavour.
409  */
410 struct rpc_clnt *
411 rpc_clone_client(struct rpc_clnt *clnt)
412 {
413         struct rpc_clnt *new;
414         int err = -ENOMEM;
415
416         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
417         if (!new)
418                 goto out_no_clnt;
419         new->cl_parent = clnt;
420         /* Turn off autobind on clones */
421         new->cl_autobind = 0;
422         INIT_LIST_HEAD(&new->cl_tasks);
423         spin_lock_init(&new->cl_lock);
424         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
425         new->cl_metrics = rpc_alloc_iostats(clnt);
426         if (new->cl_metrics == NULL)
427                 goto out_no_stats;
428         if (clnt->cl_principal) {
429                 new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
430                 if (new->cl_principal == NULL)
431                         goto out_no_principal;
432         }
433         atomic_set(&new->cl_count, 1);
434         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
435         if (err != 0)
436                 goto out_no_path;
437         if (new->cl_auth)
438                 atomic_inc(&new->cl_auth->au_count);
439         xprt_get(clnt->cl_xprt);
440         atomic_inc(&clnt->cl_count);
441         rpc_register_client(new);
442         rpciod_up();
443         return new;
444 out_no_path:
445         kfree(new->cl_principal);
446 out_no_principal:
447         rpc_free_iostats(new->cl_metrics);
448 out_no_stats:
449         kfree(new);
450 out_no_clnt:
451         dprintk("RPC:       %s: returned error %d\n", __func__, err);
452         return ERR_PTR(err);
453 }
454 EXPORT_SYMBOL_GPL(rpc_clone_client);
455
456 /*
457  * Kill all tasks for the given client.
458  * XXX: kill their descendants as well?
459  */
460 void rpc_killall_tasks(struct rpc_clnt *clnt)
461 {
462         struct rpc_task *rovr;
463
464
465         if (list_empty(&clnt->cl_tasks))
466                 return;
467         dprintk("RPC:       killing all tasks for client %p\n", clnt);
468         /*
469          * Spin lock all_tasks to prevent changes...
470          */
471         spin_lock(&clnt->cl_lock);
472         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
473                 if (!RPC_IS_ACTIVATED(rovr))
474                         continue;
475                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
476                         rovr->tk_flags |= RPC_TASK_KILLED;
477                         rpc_exit(rovr, -EIO);
478                         if (RPC_IS_QUEUED(rovr))
479                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
480                                                         rovr);
481                 }
482         }
483         spin_unlock(&clnt->cl_lock);
484 }
485 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
486
487 /*
488  * Properly shut down an RPC client, terminating all outstanding
489  * requests.
490  */
491 void rpc_shutdown_client(struct rpc_clnt *clnt)
492 {
493         dprintk("RPC:       shutting down %s client for %s\n",
494                         clnt->cl_protname, clnt->cl_server);
495
496         while (!list_empty(&clnt->cl_tasks)) {
497                 rpc_killall_tasks(clnt);
498                 wait_event_timeout(destroy_wait,
499                         list_empty(&clnt->cl_tasks), 1*HZ);
500         }
501
502         rpc_release_client(clnt);
503 }
504 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
505
506 /*
507  * Free an RPC client
508  */
509 static void
510 rpc_free_client(struct rpc_clnt *clnt)
511 {
512         dprintk("RPC:       destroying %s client for %s\n",
513                         clnt->cl_protname, clnt->cl_server);
514         rpc_clnt_remove_pipedir(clnt);
515         if (clnt->cl_parent != clnt) {
516                 rpc_release_client(clnt->cl_parent);
517                 goto out_free;
518         }
519         if (clnt->cl_server != clnt->cl_inline_name)
520                 kfree(clnt->cl_server);
521 out_free:
522         rpc_unregister_client(clnt);
523         rpc_free_iostats(clnt->cl_metrics);
524         kfree(clnt->cl_principal);
525         clnt->cl_metrics = NULL;
526         xprt_put(clnt->cl_xprt);
527         rpciod_down();
528         kfree(clnt);
529 }
530
531 /*
532  * Free an RPC client
533  */
534 static void
535 rpc_free_auth(struct rpc_clnt *clnt)
536 {
537         if (clnt->cl_auth == NULL) {
538                 rpc_free_client(clnt);
539                 return;
540         }
541
542         /*
543          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
544          *       release remaining GSS contexts. This mechanism ensures
545          *       that it can do so safely.
546          */
547         atomic_inc(&clnt->cl_count);
548         rpcauth_release(clnt->cl_auth);
549         clnt->cl_auth = NULL;
550         if (atomic_dec_and_test(&clnt->cl_count))
551                 rpc_free_client(clnt);
552 }
553
554 /*
555  * Release reference to the RPC client
556  */
557 void
558 rpc_release_client(struct rpc_clnt *clnt)
559 {
560         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
561
562         if (list_empty(&clnt->cl_tasks))
563                 wake_up(&destroy_wait);
564         if (atomic_dec_and_test(&clnt->cl_count))
565                 rpc_free_auth(clnt);
566 }
567
568 /**
569  * rpc_bind_new_program - bind a new RPC program to an existing client
570  * @old: old rpc_client
571  * @program: rpc program to set
572  * @vers: rpc program version
573  *
574  * Clones the rpc client and sets up a new RPC program. This is mainly
575  * of use for enabling different RPC programs to share the same transport.
576  * The Sun NFSv2/v3 ACL protocol can do this.
577  */
578 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
579                                       struct rpc_program *program,
580                                       u32 vers)
581 {
582         struct rpc_clnt *clnt;
583         struct rpc_version *version;
584         int err;
585
586         BUG_ON(vers >= program->nrvers || !program->version[vers]);
587         version = program->version[vers];
588         clnt = rpc_clone_client(old);
589         if (IS_ERR(clnt))
590                 goto out;
591         clnt->cl_procinfo = version->procs;
592         clnt->cl_maxproc  = version->nrprocs;
593         clnt->cl_protname = program->name;
594         clnt->cl_prog     = program->number;
595         clnt->cl_vers     = version->number;
596         clnt->cl_stats    = program->stats;
597         err = rpc_ping(clnt);
598         if (err != 0) {
599                 rpc_shutdown_client(clnt);
600                 clnt = ERR_PTR(err);
601         }
602 out:
603         return clnt;
604 }
605 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
606
607 void rpc_task_release_client(struct rpc_task *task)
608 {
609         struct rpc_clnt *clnt = task->tk_client;
610
611         if (clnt != NULL) {
612                 /* Remove from client task list */
613                 spin_lock(&clnt->cl_lock);
614                 list_del(&task->tk_task);
615                 spin_unlock(&clnt->cl_lock);
616                 task->tk_client = NULL;
617
618                 rpc_release_client(clnt);
619         }
620 }
621
622 static
623 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
624 {
625         if (clnt != NULL) {
626                 rpc_task_release_client(task);
627                 task->tk_client = clnt;
628                 atomic_inc(&clnt->cl_count);
629                 if (clnt->cl_softrtry)
630                         task->tk_flags |= RPC_TASK_SOFT;
631                 /* Add to the client's list of all tasks */
632                 spin_lock(&clnt->cl_lock);
633                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
634                 spin_unlock(&clnt->cl_lock);
635         }
636 }
637
638 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
639 {
640         rpc_task_release_client(task);
641         rpc_task_set_client(task, clnt);
642 }
643 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
644
645
646 static void
647 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
648 {
649         if (msg != NULL) {
650                 task->tk_msg.rpc_proc = msg->rpc_proc;
651                 task->tk_msg.rpc_argp = msg->rpc_argp;
652                 task->tk_msg.rpc_resp = msg->rpc_resp;
653                 if (msg->rpc_cred != NULL)
654                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
655         }
656 }
657
658 /*
659  * Default callback for async RPC calls
660  */
661 static void
662 rpc_default_callback(struct rpc_task *task, void *data)
663 {
664 }
665
666 static const struct rpc_call_ops rpc_default_ops = {
667         .rpc_call_done = rpc_default_callback,
668 };
669
670 /**
671  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
672  * @task_setup_data: pointer to task initialisation data
673  */
674 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
675 {
676         struct rpc_task *task;
677
678         task = rpc_new_task(task_setup_data);
679         if (IS_ERR(task))
680                 goto out;
681
682         rpc_task_set_client(task, task_setup_data->rpc_client);
683         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
684
685         if (task->tk_action == NULL)
686                 rpc_call_start(task);
687
688         atomic_inc(&task->tk_count);
689         rpc_execute(task);
690 out:
691         return task;
692 }
693 EXPORT_SYMBOL_GPL(rpc_run_task);
694
695 /**
696  * rpc_call_sync - Perform a synchronous RPC call
697  * @clnt: pointer to RPC client
698  * @msg: RPC call parameters
699  * @flags: RPC call flags
700  */
701 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
702 {
703         struct rpc_task *task;
704         struct rpc_task_setup task_setup_data = {
705                 .rpc_client = clnt,
706                 .rpc_message = msg,
707                 .callback_ops = &rpc_default_ops,
708                 .flags = flags,
709         };
710         int status;
711
712         BUG_ON(flags & RPC_TASK_ASYNC);
713
714         task = rpc_run_task(&task_setup_data);
715         if (IS_ERR(task))
716                 return PTR_ERR(task);
717         status = task->tk_status;
718         rpc_put_task(task);
719         return status;
720 }
721 EXPORT_SYMBOL_GPL(rpc_call_sync);
722
723 /**
724  * rpc_call_async - Perform an asynchronous RPC call
725  * @clnt: pointer to RPC client
726  * @msg: RPC call parameters
727  * @flags: RPC call flags
728  * @tk_ops: RPC call ops
729  * @data: user call data
730  */
731 int
732 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
733                const struct rpc_call_ops *tk_ops, void *data)
734 {
735         struct rpc_task *task;
736         struct rpc_task_setup task_setup_data = {
737                 .rpc_client = clnt,
738                 .rpc_message = msg,
739                 .callback_ops = tk_ops,
740                 .callback_data = data,
741                 .flags = flags|RPC_TASK_ASYNC,
742         };
743
744         task = rpc_run_task(&task_setup_data);
745         if (IS_ERR(task))
746                 return PTR_ERR(task);
747         rpc_put_task(task);
748         return 0;
749 }
750 EXPORT_SYMBOL_GPL(rpc_call_async);
751
752 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
753 /**
754  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
755  * rpc_execute against it
756  * @req: RPC request
757  * @tk_ops: RPC call ops
758  */
759 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
760                                 const struct rpc_call_ops *tk_ops)
761 {
762         struct rpc_task *task;
763         struct xdr_buf *xbufp = &req->rq_snd_buf;
764         struct rpc_task_setup task_setup_data = {
765                 .callback_ops = tk_ops,
766         };
767
768         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
769         /*
770          * Create an rpc_task to send the data
771          */
772         task = rpc_new_task(&task_setup_data);
773         if (IS_ERR(task)) {
774                 xprt_free_bc_request(req);
775                 goto out;
776         }
777         task->tk_rqstp = req;
778
779         /*
780          * Set up the xdr_buf length.
781          * This also indicates that the buffer is XDR encoded already.
782          */
783         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
784                         xbufp->tail[0].iov_len;
785
786         task->tk_action = call_bc_transmit;
787         atomic_inc(&task->tk_count);
788         BUG_ON(atomic_read(&task->tk_count) != 2);
789         rpc_execute(task);
790
791 out:
792         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
793         return task;
794 }
795 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
796
797 void
798 rpc_call_start(struct rpc_task *task)
799 {
800         task->tk_action = call_start;
801 }
802 EXPORT_SYMBOL_GPL(rpc_call_start);
803
804 /**
805  * rpc_peeraddr - extract remote peer address from clnt's xprt
806  * @clnt: RPC client structure
807  * @buf: target buffer
808  * @bufsize: length of target buffer
809  *
810  * Returns the number of bytes that are actually in the stored address.
811  */
812 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
813 {
814         size_t bytes;
815         struct rpc_xprt *xprt = clnt->cl_xprt;
816
817         bytes = sizeof(xprt->addr);
818         if (bytes > bufsize)
819                 bytes = bufsize;
820         memcpy(buf, &clnt->cl_xprt->addr, bytes);
821         return xprt->addrlen;
822 }
823 EXPORT_SYMBOL_GPL(rpc_peeraddr);
824
825 /**
826  * rpc_peeraddr2str - return remote peer address in printable format
827  * @clnt: RPC client structure
828  * @format: address format
829  *
830  */
831 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
832                              enum rpc_display_format_t format)
833 {
834         struct rpc_xprt *xprt = clnt->cl_xprt;
835
836         if (xprt->address_strings[format] != NULL)
837                 return xprt->address_strings[format];
838         else
839                 return "unprintable";
840 }
841 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
842
843 void
844 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
845 {
846         struct rpc_xprt *xprt = clnt->cl_xprt;
847         if (xprt->ops->set_buffer_size)
848                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
849 }
850 EXPORT_SYMBOL_GPL(rpc_setbufsize);
851
852 /*
853  * Return size of largest payload RPC client can support, in bytes
854  *
855  * For stream transports, this is one RPC record fragment (see RFC
856  * 1831), as we don't support multi-record requests yet.  For datagram
857  * transports, this is the size of an IP packet minus the IP, UDP, and
858  * RPC header sizes.
859  */
860 size_t rpc_max_payload(struct rpc_clnt *clnt)
861 {
862         return clnt->cl_xprt->max_payload;
863 }
864 EXPORT_SYMBOL_GPL(rpc_max_payload);
865
866 /**
867  * rpc_force_rebind - force transport to check that remote port is unchanged
868  * @clnt: client to rebind
869  *
870  */
871 void rpc_force_rebind(struct rpc_clnt *clnt)
872 {
873         if (clnt->cl_autobind)
874                 xprt_clear_bound(clnt->cl_xprt);
875 }
876 EXPORT_SYMBOL_GPL(rpc_force_rebind);
877
878 /*
879  * Restart an (async) RPC call from the call_prepare state.
880  * Usually called from within the exit handler.
881  */
882 int
883 rpc_restart_call_prepare(struct rpc_task *task)
884 {
885         if (RPC_ASSASSINATED(task))
886                 return 0;
887         task->tk_action = call_start;
888         if (task->tk_ops->rpc_call_prepare != NULL)
889                 task->tk_action = rpc_prepare_task;
890         return 1;
891 }
892 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
893
894 /*
895  * Restart an (async) RPC call. Usually called from within the
896  * exit handler.
897  */
898 int
899 rpc_restart_call(struct rpc_task *task)
900 {
901         if (RPC_ASSASSINATED(task))
902                 return 0;
903         task->tk_action = call_start;
904         return 1;
905 }
906 EXPORT_SYMBOL_GPL(rpc_restart_call);
907
908 #ifdef RPC_DEBUG
909 static const char *rpc_proc_name(const struct rpc_task *task)
910 {
911         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
912
913         if (proc) {
914                 if (proc->p_name)
915                         return proc->p_name;
916                 else
917                         return "NULL";
918         } else
919                 return "no proc";
920 }
921 #endif
922
923 /*
924  * 0.  Initial state
925  *
926  *     Other FSM states can be visited zero or more times, but
927  *     this state is visited exactly once for each RPC.
928  */
929 static void
930 call_start(struct rpc_task *task)
931 {
932         struct rpc_clnt *clnt = task->tk_client;
933
934         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
935                         clnt->cl_protname, clnt->cl_vers,
936                         rpc_proc_name(task),
937                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
938
939         /* Increment call count */
940         task->tk_msg.rpc_proc->p_count++;
941         clnt->cl_stats->rpccnt++;
942         task->tk_action = call_reserve;
943 }
944
945 /*
946  * 1.   Reserve an RPC call slot
947  */
948 static void
949 call_reserve(struct rpc_task *task)
950 {
951         dprint_status(task);
952
953         task->tk_status  = 0;
954         task->tk_action  = call_reserveresult;
955         xprt_reserve(task);
956 }
957
958 /*
959  * 1b.  Grok the result of xprt_reserve()
960  */
961 static void
962 call_reserveresult(struct rpc_task *task)
963 {
964         int status = task->tk_status;
965
966         dprint_status(task);
967
968         /*
969          * After a call to xprt_reserve(), we must have either
970          * a request slot or else an error status.
971          */
972         task->tk_status = 0;
973         if (status >= 0) {
974                 if (task->tk_rqstp) {
975                         task->tk_action = call_refresh;
976                         return;
977                 }
978
979                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
980                                 __func__, status);
981                 rpc_exit(task, -EIO);
982                 return;
983         }
984
985         /*
986          * Even though there was an error, we may have acquired
987          * a request slot somehow.  Make sure not to leak it.
988          */
989         if (task->tk_rqstp) {
990                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
991                                 __func__, status);
992                 xprt_release(task);
993         }
994
995         switch (status) {
996         case -EAGAIN:   /* woken up; retry */
997                 task->tk_action = call_reserve;
998                 return;
999         case -EIO:      /* probably a shutdown */
1000                 break;
1001         default:
1002                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1003                                 __func__, status);
1004                 break;
1005         }
1006         rpc_exit(task, status);
1007 }
1008
1009 /*
1010  * 2.   Bind and/or refresh the credentials
1011  */
1012 static void
1013 call_refresh(struct rpc_task *task)
1014 {
1015         dprint_status(task);
1016
1017         task->tk_action = call_refreshresult;
1018         task->tk_status = 0;
1019         task->tk_client->cl_stats->rpcauthrefresh++;
1020         rpcauth_refreshcred(task);
1021 }
1022
1023 /*
1024  * 2a.  Process the results of a credential refresh
1025  */
1026 static void
1027 call_refreshresult(struct rpc_task *task)
1028 {
1029         int status = task->tk_status;
1030
1031         dprint_status(task);
1032
1033         task->tk_status = 0;
1034         task->tk_action = call_refresh;
1035         switch (status) {
1036         case 0:
1037                 if (rpcauth_uptodatecred(task))
1038                         task->tk_action = call_allocate;
1039                 return;
1040         case -ETIMEDOUT:
1041                 rpc_delay(task, 3*HZ);
1042         case -EAGAIN:
1043                 status = -EACCES;
1044                 if (!task->tk_cred_retry)
1045                         break;
1046                 task->tk_cred_retry--;
1047                 dprintk("RPC: %5u %s: retry refresh creds\n",
1048                                 task->tk_pid, __func__);
1049                 return;
1050         }
1051         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1052                                 task->tk_pid, __func__, status);
1053         rpc_exit(task, status);
1054 }
1055
1056 /*
1057  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1058  *      (Note: buffer memory is freed in xprt_release).
1059  */
1060 static void
1061 call_allocate(struct rpc_task *task)
1062 {
1063         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1064         struct rpc_rqst *req = task->tk_rqstp;
1065         struct rpc_xprt *xprt = task->tk_xprt;
1066         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1067
1068         dprint_status(task);
1069
1070         task->tk_status = 0;
1071         task->tk_action = call_bind;
1072
1073         if (req->rq_buffer)
1074                 return;
1075
1076         if (proc->p_proc != 0) {
1077                 BUG_ON(proc->p_arglen == 0);
1078                 if (proc->p_decode != NULL)
1079                         BUG_ON(proc->p_replen == 0);
1080         }
1081
1082         /*
1083          * Calculate the size (in quads) of the RPC call
1084          * and reply headers, and convert both values
1085          * to byte sizes.
1086          */
1087         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1088         req->rq_callsize <<= 2;
1089         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1090         req->rq_rcvsize <<= 2;
1091
1092         req->rq_buffer = xprt->ops->buf_alloc(task,
1093                                         req->rq_callsize + req->rq_rcvsize);
1094         if (req->rq_buffer != NULL)
1095                 return;
1096
1097         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1098
1099         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1100                 task->tk_action = call_allocate;
1101                 rpc_delay(task, HZ>>4);
1102                 return;
1103         }
1104
1105         rpc_exit(task, -ERESTARTSYS);
1106 }
1107
1108 static inline int
1109 rpc_task_need_encode(struct rpc_task *task)
1110 {
1111         return task->tk_rqstp->rq_snd_buf.len == 0;
1112 }
1113
1114 static inline void
1115 rpc_task_force_reencode(struct rpc_task *task)
1116 {
1117         task->tk_rqstp->rq_snd_buf.len = 0;
1118         task->tk_rqstp->rq_bytes_sent = 0;
1119 }
1120
1121 static inline void
1122 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1123 {
1124         buf->head[0].iov_base = start;
1125         buf->head[0].iov_len = len;
1126         buf->tail[0].iov_len = 0;
1127         buf->page_len = 0;
1128         buf->flags = 0;
1129         buf->len = 0;
1130         buf->buflen = len;
1131 }
1132
1133 /*
1134  * 3.   Encode arguments of an RPC call
1135  */
1136 static void
1137 rpc_xdr_encode(struct rpc_task *task)
1138 {
1139         struct rpc_rqst *req = task->tk_rqstp;
1140         kxdreproc_t     encode;
1141         __be32          *p;
1142
1143         dprint_status(task);
1144
1145         rpc_xdr_buf_init(&req->rq_snd_buf,
1146                          req->rq_buffer,
1147                          req->rq_callsize);
1148         rpc_xdr_buf_init(&req->rq_rcv_buf,
1149                          (char *)req->rq_buffer + req->rq_callsize,
1150                          req->rq_rcvsize);
1151
1152         p = rpc_encode_header(task);
1153         if (p == NULL) {
1154                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1155                 rpc_exit(task, -EIO);
1156                 return;
1157         }
1158
1159         encode = task->tk_msg.rpc_proc->p_encode;
1160         if (encode == NULL)
1161                 return;
1162
1163         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1164                         task->tk_msg.rpc_argp);
1165 }
1166
1167 /*
1168  * 4.   Get the server port number if not yet set
1169  */
1170 static void
1171 call_bind(struct rpc_task *task)
1172 {
1173         struct rpc_xprt *xprt = task->tk_xprt;
1174
1175         dprint_status(task);
1176
1177         task->tk_action = call_connect;
1178         if (!xprt_bound(xprt)) {
1179                 task->tk_action = call_bind_status;
1180                 task->tk_timeout = xprt->bind_timeout;
1181                 xprt->ops->rpcbind(task);
1182         }
1183 }
1184
1185 /*
1186  * 4a.  Sort out bind result
1187  */
1188 static void
1189 call_bind_status(struct rpc_task *task)
1190 {
1191         int status = -EIO;
1192
1193         if (task->tk_status >= 0) {
1194                 dprint_status(task);
1195                 task->tk_status = 0;
1196                 task->tk_action = call_connect;
1197                 return;
1198         }
1199
1200         switch (task->tk_status) {
1201         case -ENOMEM:
1202                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1203                 rpc_delay(task, HZ >> 2);
1204                 goto retry_timeout;
1205         case -EACCES:
1206                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1207                                 "unavailable\n", task->tk_pid);
1208                 /* fail immediately if this is an RPC ping */
1209                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1210                         status = -EOPNOTSUPP;
1211                         break;
1212                 }
1213                 if (task->tk_rebind_retry == 0)
1214                         break;
1215                 task->tk_rebind_retry--;
1216                 rpc_delay(task, 3*HZ);
1217                 goto retry_timeout;
1218         case -ETIMEDOUT:
1219                 dprintk("RPC: %5u rpcbind request timed out\n",
1220                                 task->tk_pid);
1221                 goto retry_timeout;
1222         case -EPFNOSUPPORT:
1223                 /* server doesn't support any rpcbind version we know of */
1224                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1225                                 task->tk_pid);
1226                 break;
1227         case -EPROTONOSUPPORT:
1228                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1229                                 task->tk_pid);
1230                 task->tk_status = 0;
1231                 task->tk_action = call_bind;
1232                 return;
1233         case -ECONNREFUSED:             /* connection problems */
1234         case -ECONNRESET:
1235         case -ENOTCONN:
1236         case -EHOSTDOWN:
1237         case -EHOSTUNREACH:
1238         case -ENETUNREACH:
1239         case -EPIPE:
1240                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1241                                 task->tk_pid, task->tk_status);
1242                 if (!RPC_IS_SOFTCONN(task)) {
1243                         rpc_delay(task, 5*HZ);
1244                         goto retry_timeout;
1245                 }
1246                 status = task->tk_status;
1247                 break;
1248         default:
1249                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1250                                 task->tk_pid, -task->tk_status);
1251         }
1252
1253         rpc_exit(task, status);
1254         return;
1255
1256 retry_timeout:
1257         task->tk_action = call_timeout;
1258 }
1259
1260 /*
1261  * 4b.  Connect to the RPC server
1262  */
1263 static void
1264 call_connect(struct rpc_task *task)
1265 {
1266         struct rpc_xprt *xprt = task->tk_xprt;
1267
1268         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1269                         task->tk_pid, xprt,
1270                         (xprt_connected(xprt) ? "is" : "is not"));
1271
1272         task->tk_action = call_transmit;
1273         if (!xprt_connected(xprt)) {
1274                 task->tk_action = call_connect_status;
1275                 if (task->tk_status < 0)
1276                         return;
1277                 xprt_connect(task);
1278         }
1279 }
1280
1281 /*
1282  * 4c.  Sort out connect result
1283  */
1284 static void
1285 call_connect_status(struct rpc_task *task)
1286 {
1287         struct rpc_clnt *clnt = task->tk_client;
1288         int status = task->tk_status;
1289
1290         dprint_status(task);
1291
1292         task->tk_status = 0;
1293         if (status >= 0 || status == -EAGAIN) {
1294                 clnt->cl_stats->netreconn++;
1295                 task->tk_action = call_transmit;
1296                 return;
1297         }
1298
1299         switch (status) {
1300                 /* if soft mounted, test if we've timed out */
1301         case -ETIMEDOUT:
1302                 task->tk_action = call_timeout;
1303                 break;
1304         default:
1305                 rpc_exit(task, -EIO);
1306         }
1307 }
1308
1309 /*
1310  * 5.   Transmit the RPC request, and wait for reply
1311  */
1312 static void
1313 call_transmit(struct rpc_task *task)
1314 {
1315         dprint_status(task);
1316
1317         task->tk_action = call_status;
1318         if (task->tk_status < 0)
1319                 return;
1320         task->tk_status = xprt_prepare_transmit(task);
1321         if (task->tk_status != 0)
1322                 return;
1323         task->tk_action = call_transmit_status;
1324         /* Encode here so that rpcsec_gss can use correct sequence number. */
1325         if (rpc_task_need_encode(task)) {
1326                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1327                 rpc_xdr_encode(task);
1328                 /* Did the encode result in an error condition? */
1329                 if (task->tk_status != 0) {
1330                         /* Was the error nonfatal? */
1331                         if (task->tk_status == -EAGAIN)
1332                                 rpc_delay(task, HZ >> 4);
1333                         else
1334                                 rpc_exit(task, task->tk_status);
1335                         return;
1336                 }
1337         }
1338         xprt_transmit(task);
1339         if (task->tk_status < 0)
1340                 return;
1341         /*
1342          * On success, ensure that we call xprt_end_transmit() before sleeping
1343          * in order to allow access to the socket to other RPC requests.
1344          */
1345         call_transmit_status(task);
1346         if (rpc_reply_expected(task))
1347                 return;
1348         task->tk_action = rpc_exit_task;
1349         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1350 }
1351
1352 /*
1353  * 5a.  Handle cleanup after a transmission
1354  */
1355 static void
1356 call_transmit_status(struct rpc_task *task)
1357 {
1358         task->tk_action = call_status;
1359
1360         /*
1361          * Common case: success.  Force the compiler to put this
1362          * test first.
1363          */
1364         if (task->tk_status == 0) {
1365                 xprt_end_transmit(task);
1366                 rpc_task_force_reencode(task);
1367                 return;
1368         }
1369
1370         switch (task->tk_status) {
1371         case -EAGAIN:
1372                 break;
1373         default:
1374                 dprint_status(task);
1375                 xprt_end_transmit(task);
1376                 rpc_task_force_reencode(task);
1377                 break;
1378                 /*
1379                  * Special cases: if we've been waiting on the
1380                  * socket's write_space() callback, or if the
1381                  * socket just returned a connection error,
1382                  * then hold onto the transport lock.
1383                  */
1384         case -ECONNREFUSED:
1385         case -EHOSTDOWN:
1386         case -EHOSTUNREACH:
1387         case -ENETUNREACH:
1388                 if (RPC_IS_SOFTCONN(task)) {
1389                         xprt_end_transmit(task);
1390                         rpc_exit(task, task->tk_status);
1391                         break;
1392                 }
1393         case -ECONNRESET:
1394         case -ENOTCONN:
1395         case -EPIPE:
1396                 rpc_task_force_reencode(task);
1397         }
1398 }
1399
1400 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1401 /*
1402  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1403  * addition, disconnect on connectivity errors.
1404  */
1405 static void
1406 call_bc_transmit(struct rpc_task *task)
1407 {
1408         struct rpc_rqst *req = task->tk_rqstp;
1409
1410         BUG_ON(task->tk_status != 0);
1411         task->tk_status = xprt_prepare_transmit(task);
1412         if (task->tk_status == -EAGAIN) {
1413                 /*
1414                  * Could not reserve the transport. Try again after the
1415                  * transport is released.
1416                  */
1417                 task->tk_status = 0;
1418                 task->tk_action = call_bc_transmit;
1419                 return;
1420         }
1421
1422         task->tk_action = rpc_exit_task;
1423         if (task->tk_status < 0) {
1424                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1425                         "error: %d\n", task->tk_status);
1426                 return;
1427         }
1428
1429         xprt_transmit(task);
1430         xprt_end_transmit(task);
1431         dprint_status(task);
1432         switch (task->tk_status) {
1433         case 0:
1434                 /* Success */
1435                 break;
1436         case -EHOSTDOWN:
1437         case -EHOSTUNREACH:
1438         case -ENETUNREACH:
1439         case -ETIMEDOUT:
1440                 /*
1441                  * Problem reaching the server.  Disconnect and let the
1442                  * forechannel reestablish the connection.  The server will
1443                  * have to retransmit the backchannel request and we'll
1444                  * reprocess it.  Since these ops are idempotent, there's no
1445                  * need to cache our reply at this time.
1446                  */
1447                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1448                         "error: %d\n", task->tk_status);
1449                 xprt_conditional_disconnect(task->tk_xprt,
1450                         req->rq_connect_cookie);
1451                 break;
1452         default:
1453                 /*
1454                  * We were unable to reply and will have to drop the
1455                  * request.  The server should reconnect and retransmit.
1456                  */
1457                 BUG_ON(task->tk_status == -EAGAIN);
1458                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1459                         "error: %d\n", task->tk_status);
1460                 break;
1461         }
1462         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1463 }
1464 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1465
1466 /*
1467  * 6.   Sort out the RPC call status
1468  */
1469 static void
1470 call_status(struct rpc_task *task)
1471 {
1472         struct rpc_clnt *clnt = task->tk_client;
1473         struct rpc_rqst *req = task->tk_rqstp;
1474         int             status;
1475
1476         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1477                 task->tk_status = req->rq_reply_bytes_recvd;
1478
1479         dprint_status(task);
1480
1481         status = task->tk_status;
1482         if (status >= 0) {
1483                 task->tk_action = call_decode;
1484                 return;
1485         }
1486
1487         task->tk_status = 0;
1488         switch(status) {
1489         case -EHOSTDOWN:
1490         case -EHOSTUNREACH:
1491         case -ENETUNREACH:
1492                 /*
1493                  * Delay any retries for 3 seconds, then handle as if it
1494                  * were a timeout.
1495                  */
1496                 rpc_delay(task, 3*HZ);
1497         case -ETIMEDOUT:
1498                 task->tk_action = call_timeout;
1499                 if (task->tk_client->cl_discrtry)
1500                         xprt_conditional_disconnect(task->tk_xprt,
1501                                         req->rq_connect_cookie);
1502                 break;
1503         case -ECONNRESET:
1504         case -ECONNREFUSED:
1505                 rpc_force_rebind(clnt);
1506                 rpc_delay(task, 3*HZ);
1507         case -EPIPE:
1508         case -ENOTCONN:
1509                 task->tk_action = call_bind;
1510                 break;
1511         case -EAGAIN:
1512                 task->tk_action = call_transmit;
1513                 break;
1514         case -EIO:
1515                 /* shutdown or soft timeout */
1516                 rpc_exit(task, status);
1517                 break;
1518         default:
1519                 if (clnt->cl_chatty)
1520                         printk("%s: RPC call returned error %d\n",
1521                                clnt->cl_protname, -status);
1522                 rpc_exit(task, status);
1523         }
1524 }
1525
1526 /*
1527  * 6a.  Handle RPC timeout
1528  *      We do not release the request slot, so we keep using the
1529  *      same XID for all retransmits.
1530  */
1531 static void
1532 call_timeout(struct rpc_task *task)
1533 {
1534         struct rpc_clnt *clnt = task->tk_client;
1535
1536         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1537                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1538                 goto retry;
1539         }
1540
1541         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1542         task->tk_timeouts++;
1543
1544         if (RPC_IS_SOFTCONN(task)) {
1545                 rpc_exit(task, -ETIMEDOUT);
1546                 return;
1547         }
1548         if (RPC_IS_SOFT(task)) {
1549                 if (clnt->cl_chatty)
1550                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1551                                 clnt->cl_protname, clnt->cl_server);
1552                 if (task->tk_flags & RPC_TASK_TIMEOUT)
1553                         rpc_exit(task, -ETIMEDOUT);
1554                 else
1555                         rpc_exit(task, -EIO);
1556                 return;
1557         }
1558
1559         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1560                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1561                 if (clnt->cl_chatty)
1562                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1563                         clnt->cl_protname, clnt->cl_server);
1564         }
1565         rpc_force_rebind(clnt);
1566         /*
1567          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1568          * event? RFC2203 requires the server to drop all such requests.
1569          */
1570         rpcauth_invalcred(task);
1571
1572 retry:
1573         clnt->cl_stats->rpcretrans++;
1574         task->tk_action = call_bind;
1575         task->tk_status = 0;
1576 }
1577
1578 /*
1579  * 7.   Decode the RPC reply
1580  */
1581 static void
1582 call_decode(struct rpc_task *task)
1583 {
1584         struct rpc_clnt *clnt = task->tk_client;
1585         struct rpc_rqst *req = task->tk_rqstp;
1586         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
1587         __be32          *p;
1588
1589         dprint_status(task);
1590
1591         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1592                 if (clnt->cl_chatty)
1593                         printk(KERN_NOTICE "%s: server %s OK\n",
1594                                 clnt->cl_protname, clnt->cl_server);
1595                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1596         }
1597
1598         /*
1599          * Ensure that we see all writes made by xprt_complete_rqst()
1600          * before it changed req->rq_reply_bytes_recvd.
1601          */
1602         smp_rmb();
1603         req->rq_rcv_buf.len = req->rq_private_buf.len;
1604
1605         /* Check that the softirq receive buffer is valid */
1606         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1607                                 sizeof(req->rq_rcv_buf)) != 0);
1608
1609         if (req->rq_rcv_buf.len < 12) {
1610                 if (!RPC_IS_SOFT(task)) {
1611                         task->tk_action = call_bind;
1612                         clnt->cl_stats->rpcretrans++;
1613                         goto out_retry;
1614                 }
1615                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1616                                 clnt->cl_protname, task->tk_status);
1617                 task->tk_action = call_timeout;
1618                 goto out_retry;
1619         }
1620
1621         p = rpc_verify_header(task);
1622         if (IS_ERR(p)) {
1623                 if (p == ERR_PTR(-EAGAIN))
1624                         goto out_retry;
1625                 return;
1626         }
1627
1628         task->tk_action = rpc_exit_task;
1629
1630         if (decode) {
1631                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1632                                                       task->tk_msg.rpc_resp);
1633         }
1634         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1635                         task->tk_status);
1636         return;
1637 out_retry:
1638         task->tk_status = 0;
1639         /* Note: rpc_verify_header() may have freed the RPC slot */
1640         if (task->tk_rqstp == req) {
1641                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
1642                 if (task->tk_client->cl_discrtry)
1643                         xprt_conditional_disconnect(task->tk_xprt,
1644                                         req->rq_connect_cookie);
1645         }
1646 }
1647
1648 static __be32 *
1649 rpc_encode_header(struct rpc_task *task)
1650 {
1651         struct rpc_clnt *clnt = task->tk_client;
1652         struct rpc_rqst *req = task->tk_rqstp;
1653         __be32          *p = req->rq_svec[0].iov_base;
1654
1655         /* FIXME: check buffer size? */
1656
1657         p = xprt_skip_transport_header(task->tk_xprt, p);
1658         *p++ = req->rq_xid;             /* XID */
1659         *p++ = htonl(RPC_CALL);         /* CALL */
1660         *p++ = htonl(RPC_VERSION);      /* RPC version */
1661         *p++ = htonl(clnt->cl_prog);    /* program number */
1662         *p++ = htonl(clnt->cl_vers);    /* program version */
1663         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1664         p = rpcauth_marshcred(task, p);
1665         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1666         return p;
1667 }
1668
1669 static __be32 *
1670 rpc_verify_header(struct rpc_task *task)
1671 {
1672         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1673         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1674         __be32  *p = iov->iov_base;
1675         u32 n;
1676         int error = -EACCES;
1677
1678         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1679                 /* RFC-1014 says that the representation of XDR data must be a
1680                  * multiple of four bytes
1681                  * - if it isn't pointer subtraction in the NFS client may give
1682                  *   undefined results
1683                  */
1684                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1685                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1686                        task->tk_rqstp->rq_rcv_buf.len);
1687                 goto out_eio;
1688         }
1689         if ((len -= 3) < 0)
1690                 goto out_overflow;
1691
1692         p += 1; /* skip XID */
1693         if ((n = ntohl(*p++)) != RPC_REPLY) {
1694                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1695                         task->tk_pid, __func__, n);
1696                 goto out_garbage;
1697         }
1698
1699         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1700                 if (--len < 0)
1701                         goto out_overflow;
1702                 switch ((n = ntohl(*p++))) {
1703                 case RPC_AUTH_ERROR:
1704                         break;
1705                 case RPC_MISMATCH:
1706                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
1707                                 task->tk_pid, __func__);
1708                         error = -EPROTONOSUPPORT;
1709                         goto out_err;
1710                 default:
1711                         dprintk("RPC: %5u %s: RPC call rejected, "
1712                                 "unknown error: %x\n",
1713                                 task->tk_pid, __func__, n);
1714                         goto out_eio;
1715                 }
1716                 if (--len < 0)
1717                         goto out_overflow;
1718                 switch ((n = ntohl(*p++))) {
1719                 case RPC_AUTH_REJECTEDCRED:
1720                 case RPC_AUTH_REJECTEDVERF:
1721                 case RPCSEC_GSS_CREDPROBLEM:
1722                 case RPCSEC_GSS_CTXPROBLEM:
1723                         if (!task->tk_cred_retry)
1724                                 break;
1725                         task->tk_cred_retry--;
1726                         dprintk("RPC: %5u %s: retry stale creds\n",
1727                                         task->tk_pid, __func__);
1728                         rpcauth_invalcred(task);
1729                         /* Ensure we obtain a new XID! */
1730                         xprt_release(task);
1731                         task->tk_action = call_reserve;
1732                         goto out_retry;
1733                 case RPC_AUTH_BADCRED:
1734                 case RPC_AUTH_BADVERF:
1735                         /* possibly garbled cred/verf? */
1736                         if (!task->tk_garb_retry)
1737                                 break;
1738                         task->tk_garb_retry--;
1739                         dprintk("RPC: %5u %s: retry garbled creds\n",
1740                                         task->tk_pid, __func__);
1741                         task->tk_action = call_bind;
1742                         goto out_retry;
1743                 case RPC_AUTH_TOOWEAK:
1744                         printk(KERN_NOTICE "RPC: server %s requires stronger "
1745                                "authentication.\n", task->tk_client->cl_server);
1746                         break;
1747                 default:
1748                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1749                                         task->tk_pid, __func__, n);
1750                         error = -EIO;
1751                 }
1752                 dprintk("RPC: %5u %s: call rejected %d\n",
1753                                 task->tk_pid, __func__, n);
1754                 goto out_err;
1755         }
1756         if (!(p = rpcauth_checkverf(task, p))) {
1757                 dprintk("RPC: %5u %s: auth check failed\n",
1758                                 task->tk_pid, __func__);
1759                 goto out_garbage;               /* bad verifier, retry */
1760         }
1761         len = p - (__be32 *)iov->iov_base - 1;
1762         if (len < 0)
1763                 goto out_overflow;
1764         switch ((n = ntohl(*p++))) {
1765         case RPC_SUCCESS:
1766                 return p;
1767         case RPC_PROG_UNAVAIL:
1768                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1769                                 task->tk_pid, __func__,
1770                                 (unsigned int)task->tk_client->cl_prog,
1771                                 task->tk_client->cl_server);
1772                 error = -EPFNOSUPPORT;
1773                 goto out_err;
1774         case RPC_PROG_MISMATCH:
1775                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1776                                 "server %s\n", task->tk_pid, __func__,
1777                                 (unsigned int)task->tk_client->cl_prog,
1778                                 (unsigned int)task->tk_client->cl_vers,
1779                                 task->tk_client->cl_server);
1780                 error = -EPROTONOSUPPORT;
1781                 goto out_err;
1782         case RPC_PROC_UNAVAIL:
1783                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1784                                 "version %u on server %s\n",
1785                                 task->tk_pid, __func__,
1786                                 rpc_proc_name(task),
1787                                 task->tk_client->cl_prog,
1788                                 task->tk_client->cl_vers,
1789                                 task->tk_client->cl_server);
1790                 error = -EOPNOTSUPP;
1791                 goto out_err;
1792         case RPC_GARBAGE_ARGS:
1793                 dprintk("RPC: %5u %s: server saw garbage\n",
1794                                 task->tk_pid, __func__);
1795                 break;                  /* retry */
1796         default:
1797                 dprintk("RPC: %5u %s: server accept status: %x\n",
1798                                 task->tk_pid, __func__, n);
1799                 /* Also retry */
1800         }
1801
1802 out_garbage:
1803         task->tk_client->cl_stats->rpcgarbage++;
1804         if (task->tk_garb_retry) {
1805                 task->tk_garb_retry--;
1806                 dprintk("RPC: %5u %s: retrying\n",
1807                                 task->tk_pid, __func__);
1808                 task->tk_action = call_bind;
1809 out_retry:
1810                 return ERR_PTR(-EAGAIN);
1811         }
1812 out_eio:
1813         error = -EIO;
1814 out_err:
1815         rpc_exit(task, error);
1816         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1817                         __func__, error);
1818         return ERR_PTR(error);
1819 out_overflow:
1820         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1821                         __func__);
1822         goto out_garbage;
1823 }
1824
1825 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1826 {
1827 }
1828
1829 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1830 {
1831         return 0;
1832 }
1833
1834 static struct rpc_procinfo rpcproc_null = {
1835         .p_encode = rpcproc_encode_null,
1836         .p_decode = rpcproc_decode_null,
1837 };
1838
1839 static int rpc_ping(struct rpc_clnt *clnt)
1840 {
1841         struct rpc_message msg = {
1842                 .rpc_proc = &rpcproc_null,
1843         };
1844         int err;
1845         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1846         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
1847         put_rpccred(msg.rpc_cred);
1848         return err;
1849 }
1850
1851 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1852 {
1853         struct rpc_message msg = {
1854                 .rpc_proc = &rpcproc_null,
1855                 .rpc_cred = cred,
1856         };
1857         struct rpc_task_setup task_setup_data = {
1858                 .rpc_client = clnt,
1859                 .rpc_message = &msg,
1860                 .callback_ops = &rpc_default_ops,
1861                 .flags = flags,
1862         };
1863         return rpc_run_task(&task_setup_data);
1864 }
1865 EXPORT_SYMBOL_GPL(rpc_call_null);
1866
1867 #ifdef RPC_DEBUG
1868 static void rpc_show_header(void)
1869 {
1870         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1871                 "-timeout ---ops--\n");
1872 }
1873
1874 static void rpc_show_task(const struct rpc_clnt *clnt,
1875                           const struct rpc_task *task)
1876 {
1877         const char *rpc_waitq = "none";
1878
1879         if (RPC_IS_QUEUED(task))
1880                 rpc_waitq = rpc_qname(task->tk_waitqueue);
1881
1882         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
1883                 task->tk_pid, task->tk_flags, task->tk_status,
1884                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1885                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1886                 task->tk_action, rpc_waitq);
1887 }
1888
1889 void rpc_show_tasks(struct net *net)
1890 {
1891         struct rpc_clnt *clnt;
1892         struct rpc_task *task;
1893         int header = 0;
1894         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1895
1896         spin_lock(&sn->rpc_client_lock);
1897         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
1898                 spin_lock(&clnt->cl_lock);
1899                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1900                         if (!header) {
1901                                 rpc_show_header();
1902                                 header++;
1903                         }
1904                         rpc_show_task(clnt, task);
1905                 }
1906                 spin_unlock(&clnt->cl_lock);
1907         }
1908         spin_unlock(&sn->rpc_client_lock);
1909 }
1910 #endif