xref: /linux/net/sunrpc/clnt.c (revision dfff0fa65ab15db45acd64b3189787d37ab163cd)
1 /*
2  *  linux/net/sunrpc/clnt.c
3  *
4  *  This file contains the high-level RPC interface.
5  *  It is modeled as a finite state machine to support both synchronous
6  *  and asynchronous requests.
7  *
8  *  -	RPC header generation and argument serialization.
9  *  -	Credential refresh.
10  *  -	TCP connect handling.
11  *  -	Retry of operation when it is suspected the operation failed because
12  *	of uid squashing on the server, or when the credentials were stale
13  *	and need to be refreshed, or when a packet was damaged in transit.
14  *	This may be have to be moved to the VFS layer.
15  *
16  *  NB: BSD uses a more intelligent approach to guessing when a request
17  *  or reply has been lost by keeping the RTO estimate for each procedure.
18  *  We currently make do with a constant timeout value.
19  *
20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
22  */
23 
24 #include <asm/system.h>
25 
26 #include <linux/module.h>
27 #include <linux/types.h>
28 #include <linux/kallsyms.h>
29 #include <linux/mm.h>
30 #include <linux/slab.h>
31 #include <linux/utsname.h>
32 #include <linux/workqueue.h>
33 #include <linux/in6.h>
34 
35 #include <linux/sunrpc/clnt.h>
36 #include <linux/sunrpc/rpc_pipe_fs.h>
37 #include <linux/sunrpc/metrics.h>
38 #include <linux/sunrpc/bc_xprt.h>
39 
40 #include "sunrpc.h"
41 
42 #ifdef RPC_DEBUG
43 # define RPCDBG_FACILITY	RPCDBG_CALL
44 #endif
45 
46 #define dprint_status(t)					\
47 	dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,		\
48 			__func__, t->tk_status)
49 
50 /*
51  * All RPC clients are linked into this list
52  */
53 static LIST_HEAD(all_clients);
54 static DEFINE_SPINLOCK(rpc_client_lock);
55 
56 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
57 
58 
59 static void	call_start(struct rpc_task *task);
60 static void	call_reserve(struct rpc_task *task);
61 static void	call_reserveresult(struct rpc_task *task);
62 static void	call_allocate(struct rpc_task *task);
63 static void	call_decode(struct rpc_task *task);
64 static void	call_bind(struct rpc_task *task);
65 static void	call_bind_status(struct rpc_task *task);
66 static void	call_transmit(struct rpc_task *task);
67 #if defined(CONFIG_NFS_V4_1)
68 static void	call_bc_transmit(struct rpc_task *task);
69 #endif /* CONFIG_NFS_V4_1 */
70 static void	call_status(struct rpc_task *task);
71 static void	call_transmit_status(struct rpc_task *task);
72 static void	call_refresh(struct rpc_task *task);
73 static void	call_refreshresult(struct rpc_task *task);
74 static void	call_timeout(struct rpc_task *task);
75 static void	call_connect(struct rpc_task *task);
76 static void	call_connect_status(struct rpc_task *task);
77 
78 static __be32	*rpc_encode_header(struct rpc_task *task);
79 static __be32	*rpc_verify_header(struct rpc_task *task);
80 static int	rpc_ping(struct rpc_clnt *clnt, int flags);
81 
82 static void rpc_register_client(struct rpc_clnt *clnt)
83 {
84 	spin_lock(&rpc_client_lock);
85 	list_add(&clnt->cl_clients, &all_clients);
86 	spin_unlock(&rpc_client_lock);
87 }
88 
89 static void rpc_unregister_client(struct rpc_clnt *clnt)
90 {
91 	spin_lock(&rpc_client_lock);
92 	list_del(&clnt->cl_clients);
93 	spin_unlock(&rpc_client_lock);
94 }
95 
96 static int
97 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
98 {
99 	static uint32_t clntid;
100 	int error;
101 
102 	clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
103 	clnt->cl_dentry = ERR_PTR(-ENOENT);
104 	if (dir_name == NULL)
105 		return 0;
106 
107 	clnt->cl_vfsmnt = rpc_get_mount();
108 	if (IS_ERR(clnt->cl_vfsmnt))
109 		return PTR_ERR(clnt->cl_vfsmnt);
110 
111 	for (;;) {
112 		snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
113 				"%s/clnt%x", dir_name,
114 				(unsigned int)clntid++);
115 		clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
116 		clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
117 		if (!IS_ERR(clnt->cl_dentry))
118 			return 0;
119 		error = PTR_ERR(clnt->cl_dentry);
120 		if (error != -EEXIST) {
121 			printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
122 					clnt->cl_pathname, error);
123 			rpc_put_mount();
124 			return error;
125 		}
126 	}
127 }
128 
129 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
130 {
131 	struct rpc_program	*program = args->program;
132 	struct rpc_version	*version;
133 	struct rpc_clnt		*clnt = NULL;
134 	struct rpc_auth		*auth;
135 	int err;
136 	size_t len;
137 
138 	/* sanity check the name before trying to print it */
139 	err = -EINVAL;
140 	len = strlen(args->servername);
141 	if (len > RPC_MAXNETNAMELEN)
142 		goto out_no_rpciod;
143 	len++;
144 
145 	dprintk("RPC:       creating %s client for %s (xprt %p)\n",
146 			program->name, args->servername, xprt);
147 
148 	err = rpciod_up();
149 	if (err)
150 		goto out_no_rpciod;
151 	err = -EINVAL;
152 	if (!xprt)
153 		goto out_no_xprt;
154 
155 	if (args->version >= program->nrvers)
156 		goto out_err;
157 	version = program->version[args->version];
158 	if (version == NULL)
159 		goto out_err;
160 
161 	err = -ENOMEM;
162 	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
163 	if (!clnt)
164 		goto out_err;
165 	clnt->cl_parent = clnt;
166 
167 	clnt->cl_server = clnt->cl_inline_name;
168 	if (len > sizeof(clnt->cl_inline_name)) {
169 		char *buf = kmalloc(len, GFP_KERNEL);
170 		if (buf != NULL)
171 			clnt->cl_server = buf;
172 		else
173 			len = sizeof(clnt->cl_inline_name);
174 	}
175 	strlcpy(clnt->cl_server, args->servername, len);
176 
177 	clnt->cl_xprt     = xprt;
178 	clnt->cl_procinfo = version->procs;
179 	clnt->cl_maxproc  = version->nrprocs;
180 	clnt->cl_protname = program->name;
181 	clnt->cl_prog     = args->prognumber ? : program->number;
182 	clnt->cl_vers     = version->number;
183 	clnt->cl_stats    = program->stats;
184 	clnt->cl_metrics  = rpc_alloc_iostats(clnt);
185 	err = -ENOMEM;
186 	if (clnt->cl_metrics == NULL)
187 		goto out_no_stats;
188 	clnt->cl_program  = program;
189 	INIT_LIST_HEAD(&clnt->cl_tasks);
190 	spin_lock_init(&clnt->cl_lock);
191 
192 	if (!xprt_bound(clnt->cl_xprt))
193 		clnt->cl_autobind = 1;
194 
195 	clnt->cl_timeout = xprt->timeout;
196 	if (args->timeout != NULL) {
197 		memcpy(&clnt->cl_timeout_default, args->timeout,
198 				sizeof(clnt->cl_timeout_default));
199 		clnt->cl_timeout = &clnt->cl_timeout_default;
200 	}
201 
202 	clnt->cl_rtt = &clnt->cl_rtt_default;
203 	rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
204 	clnt->cl_principal = NULL;
205 	if (args->client_name) {
206 		clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
207 		if (!clnt->cl_principal)
208 			goto out_no_principal;
209 	}
210 
211 	kref_init(&clnt->cl_kref);
212 
213 	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
214 	if (err < 0)
215 		goto out_no_path;
216 
217 	auth = rpcauth_create(args->authflavor, clnt);
218 	if (IS_ERR(auth)) {
219 		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
220 				args->authflavor);
221 		err = PTR_ERR(auth);
222 		goto out_no_auth;
223 	}
224 
225 	/* save the nodename */
226 	clnt->cl_nodelen = strlen(init_utsname()->nodename);
227 	if (clnt->cl_nodelen > UNX_MAXNODENAME)
228 		clnt->cl_nodelen = UNX_MAXNODENAME;
229 	memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen);
230 	rpc_register_client(clnt);
231 	return clnt;
232 
233 out_no_auth:
234 	if (!IS_ERR(clnt->cl_dentry)) {
235 		rpc_rmdir(clnt->cl_dentry);
236 		rpc_put_mount();
237 	}
238 out_no_path:
239 	kfree(clnt->cl_principal);
240 out_no_principal:
241 	rpc_free_iostats(clnt->cl_metrics);
242 out_no_stats:
243 	if (clnt->cl_server != clnt->cl_inline_name)
244 		kfree(clnt->cl_server);
245 	kfree(clnt);
246 out_err:
247 	xprt_put(xprt);
248 out_no_xprt:
249 	rpciod_down();
250 out_no_rpciod:
251 	return ERR_PTR(err);
252 }
253 
254 /*
255  * rpc_create - create an RPC client and transport with one call
256  * @args: rpc_clnt create argument structure
257  *
258  * Creates and initializes an RPC transport and an RPC client.
259  *
260  * It can ping the server in order to determine if it is up, and to see if
261  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
262  * this behavior so asynchronous tasks can also use rpc_create.
263  */
264 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
265 {
266 	struct rpc_xprt *xprt;
267 	struct rpc_clnt *clnt;
268 	struct xprt_create xprtargs = {
269 		.ident = args->protocol,
270 		.srcaddr = args->saddress,
271 		.dstaddr = args->address,
272 		.addrlen = args->addrsize,
273 	};
274 	char servername[48];
275 
276 	/*
277 	 * If the caller chooses not to specify a hostname, whip
278 	 * up a string representation of the passed-in address.
279 	 */
280 	if (args->servername == NULL) {
281 		servername[0] = '\0';
282 		switch (args->address->sa_family) {
283 		case AF_INET: {
284 			struct sockaddr_in *sin =
285 					(struct sockaddr_in *)args->address;
286 			snprintf(servername, sizeof(servername), "%pI4",
287 				 &sin->sin_addr.s_addr);
288 			break;
289 		}
290 		case AF_INET6: {
291 			struct sockaddr_in6 *sin =
292 					(struct sockaddr_in6 *)args->address;
293 			snprintf(servername, sizeof(servername), "%pI6",
294 				 &sin->sin6_addr);
295 			break;
296 		}
297 		default:
298 			/* caller wants default server name, but
299 			 * address family isn't recognized. */
300 			return ERR_PTR(-EINVAL);
301 		}
302 		args->servername = servername;
303 	}
304 
305 	xprt = xprt_create_transport(&xprtargs);
306 	if (IS_ERR(xprt))
307 		return (struct rpc_clnt *)xprt;
308 
309 	/*
310 	 * By default, kernel RPC client connects from a reserved port.
311 	 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
312 	 * but it is always enabled for rpciod, which handles the connect
313 	 * operation.
314 	 */
315 	xprt->resvport = 1;
316 	if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
317 		xprt->resvport = 0;
318 
319 	clnt = rpc_new_client(args, xprt);
320 	if (IS_ERR(clnt))
321 		return clnt;
322 
323 	if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
324 		int err = rpc_ping(clnt, RPC_TASK_SOFT);
325 		if (err != 0) {
326 			rpc_shutdown_client(clnt);
327 			return ERR_PTR(err);
328 		}
329 	}
330 
331 	clnt->cl_softrtry = 1;
332 	if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
333 		clnt->cl_softrtry = 0;
334 
335 	if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
336 		clnt->cl_autobind = 1;
337 	if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
338 		clnt->cl_discrtry = 1;
339 	if (!(args->flags & RPC_CLNT_CREATE_QUIET))
340 		clnt->cl_chatty = 1;
341 
342 	return clnt;
343 }
344 EXPORT_SYMBOL_GPL(rpc_create);
345 
346 /*
347  * This function clones the RPC client structure. It allows us to share the
348  * same transport while varying parameters such as the authentication
349  * flavour.
350  */
351 struct rpc_clnt *
352 rpc_clone_client(struct rpc_clnt *clnt)
353 {
354 	struct rpc_clnt *new;
355 	int err = -ENOMEM;
356 
357 	new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
358 	if (!new)
359 		goto out_no_clnt;
360 	new->cl_parent = clnt;
361 	/* Turn off autobind on clones */
362 	new->cl_autobind = 0;
363 	INIT_LIST_HEAD(&new->cl_tasks);
364 	spin_lock_init(&new->cl_lock);
365 	rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
366 	new->cl_metrics = rpc_alloc_iostats(clnt);
367 	if (new->cl_metrics == NULL)
368 		goto out_no_stats;
369 	if (clnt->cl_principal) {
370 		new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
371 		if (new->cl_principal == NULL)
372 			goto out_no_principal;
373 	}
374 	kref_init(&new->cl_kref);
375 	err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
376 	if (err != 0)
377 		goto out_no_path;
378 	if (new->cl_auth)
379 		atomic_inc(&new->cl_auth->au_count);
380 	xprt_get(clnt->cl_xprt);
381 	kref_get(&clnt->cl_kref);
382 	rpc_register_client(new);
383 	rpciod_up();
384 	return new;
385 out_no_path:
386 	kfree(new->cl_principal);
387 out_no_principal:
388 	rpc_free_iostats(new->cl_metrics);
389 out_no_stats:
390 	kfree(new);
391 out_no_clnt:
392 	dprintk("RPC:       %s: returned error %d\n", __func__, err);
393 	return ERR_PTR(err);
394 }
395 EXPORT_SYMBOL_GPL(rpc_clone_client);
396 
397 /*
398  * Properly shut down an RPC client, terminating all outstanding
399  * requests.
400  */
401 void rpc_shutdown_client(struct rpc_clnt *clnt)
402 {
403 	dprintk("RPC:       shutting down %s client for %s\n",
404 			clnt->cl_protname, clnt->cl_server);
405 
406 	while (!list_empty(&clnt->cl_tasks)) {
407 		rpc_killall_tasks(clnt);
408 		wait_event_timeout(destroy_wait,
409 			list_empty(&clnt->cl_tasks), 1*HZ);
410 	}
411 
412 	rpc_release_client(clnt);
413 }
414 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
415 
416 /*
417  * Free an RPC client
418  */
419 static void
420 rpc_free_client(struct kref *kref)
421 {
422 	struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
423 
424 	dprintk("RPC:       destroying %s client for %s\n",
425 			clnt->cl_protname, clnt->cl_server);
426 	if (!IS_ERR(clnt->cl_dentry)) {
427 		rpc_rmdir(clnt->cl_dentry);
428 		rpc_put_mount();
429 	}
430 	if (clnt->cl_parent != clnt) {
431 		rpc_release_client(clnt->cl_parent);
432 		goto out_free;
433 	}
434 	if (clnt->cl_server != clnt->cl_inline_name)
435 		kfree(clnt->cl_server);
436 out_free:
437 	rpc_unregister_client(clnt);
438 	rpc_free_iostats(clnt->cl_metrics);
439 	kfree(clnt->cl_principal);
440 	clnt->cl_metrics = NULL;
441 	xprt_put(clnt->cl_xprt);
442 	rpciod_down();
443 	kfree(clnt);
444 }
445 
446 /*
447  * Free an RPC client
448  */
449 static void
450 rpc_free_auth(struct kref *kref)
451 {
452 	struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
453 
454 	if (clnt->cl_auth == NULL) {
455 		rpc_free_client(kref);
456 		return;
457 	}
458 
459 	/*
460 	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
461 	 *       release remaining GSS contexts. This mechanism ensures
462 	 *       that it can do so safely.
463 	 */
464 	kref_init(kref);
465 	rpcauth_release(clnt->cl_auth);
466 	clnt->cl_auth = NULL;
467 	kref_put(kref, rpc_free_client);
468 }
469 
470 /*
471  * Release reference to the RPC client
472  */
473 void
474 rpc_release_client(struct rpc_clnt *clnt)
475 {
476 	dprintk("RPC:       rpc_release_client(%p)\n", clnt);
477 
478 	if (list_empty(&clnt->cl_tasks))
479 		wake_up(&destroy_wait);
480 	kref_put(&clnt->cl_kref, rpc_free_auth);
481 }
482 
483 /**
484  * rpc_bind_new_program - bind a new RPC program to an existing client
485  * @old: old rpc_client
486  * @program: rpc program to set
487  * @vers: rpc program version
488  *
489  * Clones the rpc client and sets up a new RPC program. This is mainly
490  * of use for enabling different RPC programs to share the same transport.
491  * The Sun NFSv2/v3 ACL protocol can do this.
492  */
493 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
494 				      struct rpc_program *program,
495 				      u32 vers)
496 {
497 	struct rpc_clnt *clnt;
498 	struct rpc_version *version;
499 	int err;
500 
501 	BUG_ON(vers >= program->nrvers || !program->version[vers]);
502 	version = program->version[vers];
503 	clnt = rpc_clone_client(old);
504 	if (IS_ERR(clnt))
505 		goto out;
506 	clnt->cl_procinfo = version->procs;
507 	clnt->cl_maxproc  = version->nrprocs;
508 	clnt->cl_protname = program->name;
509 	clnt->cl_prog     = program->number;
510 	clnt->cl_vers     = version->number;
511 	clnt->cl_stats    = program->stats;
512 	err = rpc_ping(clnt, RPC_TASK_SOFT);
513 	if (err != 0) {
514 		rpc_shutdown_client(clnt);
515 		clnt = ERR_PTR(err);
516 	}
517 out:
518 	return clnt;
519 }
520 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
521 
522 /*
523  * Default callback for async RPC calls
524  */
525 static void
526 rpc_default_callback(struct rpc_task *task, void *data)
527 {
528 }
529 
530 static const struct rpc_call_ops rpc_default_ops = {
531 	.rpc_call_done = rpc_default_callback,
532 };
533 
534 /**
535  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
536  * @task_setup_data: pointer to task initialisation data
537  */
538 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
539 {
540 	struct rpc_task *task, *ret;
541 
542 	task = rpc_new_task(task_setup_data);
543 	if (task == NULL) {
544 		rpc_release_calldata(task_setup_data->callback_ops,
545 				task_setup_data->callback_data);
546 		ret = ERR_PTR(-ENOMEM);
547 		goto out;
548 	}
549 
550 	if (task->tk_status != 0) {
551 		ret = ERR_PTR(task->tk_status);
552 		rpc_put_task(task);
553 		goto out;
554 	}
555 	atomic_inc(&task->tk_count);
556 	rpc_execute(task);
557 	ret = task;
558 out:
559 	return ret;
560 }
561 EXPORT_SYMBOL_GPL(rpc_run_task);
562 
563 /**
564  * rpc_call_sync - Perform a synchronous RPC call
565  * @clnt: pointer to RPC client
566  * @msg: RPC call parameters
567  * @flags: RPC call flags
568  */
569 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
570 {
571 	struct rpc_task	*task;
572 	struct rpc_task_setup task_setup_data = {
573 		.rpc_client = clnt,
574 		.rpc_message = msg,
575 		.callback_ops = &rpc_default_ops,
576 		.flags = flags,
577 	};
578 	int status;
579 
580 	BUG_ON(flags & RPC_TASK_ASYNC);
581 
582 	task = rpc_run_task(&task_setup_data);
583 	if (IS_ERR(task))
584 		return PTR_ERR(task);
585 	status = task->tk_status;
586 	rpc_put_task(task);
587 	return status;
588 }
589 EXPORT_SYMBOL_GPL(rpc_call_sync);
590 
591 /**
592  * rpc_call_async - Perform an asynchronous RPC call
593  * @clnt: pointer to RPC client
594  * @msg: RPC call parameters
595  * @flags: RPC call flags
596  * @tk_ops: RPC call ops
597  * @data: user call data
598  */
599 int
600 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
601 	       const struct rpc_call_ops *tk_ops, void *data)
602 {
603 	struct rpc_task	*task;
604 	struct rpc_task_setup task_setup_data = {
605 		.rpc_client = clnt,
606 		.rpc_message = msg,
607 		.callback_ops = tk_ops,
608 		.callback_data = data,
609 		.flags = flags|RPC_TASK_ASYNC,
610 	};
611 
612 	task = rpc_run_task(&task_setup_data);
613 	if (IS_ERR(task))
614 		return PTR_ERR(task);
615 	rpc_put_task(task);
616 	return 0;
617 }
618 EXPORT_SYMBOL_GPL(rpc_call_async);
619 
620 #if defined(CONFIG_NFS_V4_1)
621 /**
622  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
623  * rpc_execute against it
624  * @ops: RPC call ops
625  */
626 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
627 					const struct rpc_call_ops *tk_ops)
628 {
629 	struct rpc_task *task;
630 	struct xdr_buf *xbufp = &req->rq_snd_buf;
631 	struct rpc_task_setup task_setup_data = {
632 		.callback_ops = tk_ops,
633 	};
634 
635 	dprintk("RPC: rpc_run_bc_task req= %p\n", req);
636 	/*
637 	 * Create an rpc_task to send the data
638 	 */
639 	task = rpc_new_task(&task_setup_data);
640 	if (!task) {
641 		xprt_free_bc_request(req);
642 		goto out;
643 	}
644 	task->tk_rqstp = req;
645 
646 	/*
647 	 * Set up the xdr_buf length.
648 	 * This also indicates that the buffer is XDR encoded already.
649 	 */
650 	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
651 			xbufp->tail[0].iov_len;
652 
653 	task->tk_action = call_bc_transmit;
654 	atomic_inc(&task->tk_count);
655 	BUG_ON(atomic_read(&task->tk_count) != 2);
656 	rpc_execute(task);
657 
658 out:
659 	dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
660 	return task;
661 }
662 #endif /* CONFIG_NFS_V4_1 */
663 
664 void
665 rpc_call_start(struct rpc_task *task)
666 {
667 	task->tk_action = call_start;
668 }
669 EXPORT_SYMBOL_GPL(rpc_call_start);
670 
671 /**
672  * rpc_peeraddr - extract remote peer address from clnt's xprt
673  * @clnt: RPC client structure
674  * @buf: target buffer
675  * @bufsize: length of target buffer
676  *
677  * Returns the number of bytes that are actually in the stored address.
678  */
679 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
680 {
681 	size_t bytes;
682 	struct rpc_xprt *xprt = clnt->cl_xprt;
683 
684 	bytes = sizeof(xprt->addr);
685 	if (bytes > bufsize)
686 		bytes = bufsize;
687 	memcpy(buf, &clnt->cl_xprt->addr, bytes);
688 	return xprt->addrlen;
689 }
690 EXPORT_SYMBOL_GPL(rpc_peeraddr);
691 
692 /**
693  * rpc_peeraddr2str - return remote peer address in printable format
694  * @clnt: RPC client structure
695  * @format: address format
696  *
697  */
698 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
699 			     enum rpc_display_format_t format)
700 {
701 	struct rpc_xprt *xprt = clnt->cl_xprt;
702 
703 	if (xprt->address_strings[format] != NULL)
704 		return xprt->address_strings[format];
705 	else
706 		return "unprintable";
707 }
708 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
709 
710 void
711 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
712 {
713 	struct rpc_xprt *xprt = clnt->cl_xprt;
714 	if (xprt->ops->set_buffer_size)
715 		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
716 }
717 EXPORT_SYMBOL_GPL(rpc_setbufsize);
718 
719 /*
720  * Return size of largest payload RPC client can support, in bytes
721  *
722  * For stream transports, this is one RPC record fragment (see RFC
723  * 1831), as we don't support multi-record requests yet.  For datagram
724  * transports, this is the size of an IP packet minus the IP, UDP, and
725  * RPC header sizes.
726  */
727 size_t rpc_max_payload(struct rpc_clnt *clnt)
728 {
729 	return clnt->cl_xprt->max_payload;
730 }
731 EXPORT_SYMBOL_GPL(rpc_max_payload);
732 
733 /**
734  * rpc_force_rebind - force transport to check that remote port is unchanged
735  * @clnt: client to rebind
736  *
737  */
738 void rpc_force_rebind(struct rpc_clnt *clnt)
739 {
740 	if (clnt->cl_autobind)
741 		xprt_clear_bound(clnt->cl_xprt);
742 }
743 EXPORT_SYMBOL_GPL(rpc_force_rebind);
744 
745 /*
746  * Restart an (async) RPC call from the call_prepare state.
747  * Usually called from within the exit handler.
748  */
749 void
750 rpc_restart_call_prepare(struct rpc_task *task)
751 {
752 	if (RPC_ASSASSINATED(task))
753 		return;
754 	task->tk_action = rpc_prepare_task;
755 }
756 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
757 
758 /*
759  * Restart an (async) RPC call. Usually called from within the
760  * exit handler.
761  */
762 void
763 rpc_restart_call(struct rpc_task *task)
764 {
765 	if (RPC_ASSASSINATED(task))
766 		return;
767 
768 	task->tk_action = call_start;
769 }
770 EXPORT_SYMBOL_GPL(rpc_restart_call);
771 
772 #ifdef RPC_DEBUG
773 static const char *rpc_proc_name(const struct rpc_task *task)
774 {
775 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
776 
777 	if (proc) {
778 		if (proc->p_name)
779 			return proc->p_name;
780 		else
781 			return "NULL";
782 	} else
783 		return "no proc";
784 }
785 #endif
786 
787 /*
788  * 0.  Initial state
789  *
790  *     Other FSM states can be visited zero or more times, but
791  *     this state is visited exactly once for each RPC.
792  */
793 static void
794 call_start(struct rpc_task *task)
795 {
796 	struct rpc_clnt	*clnt = task->tk_client;
797 
798 	dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
799 			clnt->cl_protname, clnt->cl_vers,
800 			rpc_proc_name(task),
801 			(RPC_IS_ASYNC(task) ? "async" : "sync"));
802 
803 	/* Increment call count */
804 	task->tk_msg.rpc_proc->p_count++;
805 	clnt->cl_stats->rpccnt++;
806 	task->tk_action = call_reserve;
807 }
808 
809 /*
810  * 1.	Reserve an RPC call slot
811  */
812 static void
813 call_reserve(struct rpc_task *task)
814 {
815 	dprint_status(task);
816 
817 	if (!rpcauth_uptodatecred(task)) {
818 		task->tk_action = call_refresh;
819 		return;
820 	}
821 
822 	task->tk_status  = 0;
823 	task->tk_action  = call_reserveresult;
824 	xprt_reserve(task);
825 }
826 
827 /*
828  * 1b.	Grok the result of xprt_reserve()
829  */
830 static void
831 call_reserveresult(struct rpc_task *task)
832 {
833 	int status = task->tk_status;
834 
835 	dprint_status(task);
836 
837 	/*
838 	 * After a call to xprt_reserve(), we must have either
839 	 * a request slot or else an error status.
840 	 */
841 	task->tk_status = 0;
842 	if (status >= 0) {
843 		if (task->tk_rqstp) {
844 			task->tk_action = call_allocate;
845 			return;
846 		}
847 
848 		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
849 				__func__, status);
850 		rpc_exit(task, -EIO);
851 		return;
852 	}
853 
854 	/*
855 	 * Even though there was an error, we may have acquired
856 	 * a request slot somehow.  Make sure not to leak it.
857 	 */
858 	if (task->tk_rqstp) {
859 		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
860 				__func__, status);
861 		xprt_release(task);
862 	}
863 
864 	switch (status) {
865 	case -EAGAIN:	/* woken up; retry */
866 		task->tk_action = call_reserve;
867 		return;
868 	case -EIO:	/* probably a shutdown */
869 		break;
870 	default:
871 		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
872 				__func__, status);
873 		break;
874 	}
875 	rpc_exit(task, status);
876 }
877 
878 /*
879  * 2.	Allocate the buffer. For details, see sched.c:rpc_malloc.
880  *	(Note: buffer memory is freed in xprt_release).
881  */
882 static void
883 call_allocate(struct rpc_task *task)
884 {
885 	unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
886 	struct rpc_rqst *req = task->tk_rqstp;
887 	struct rpc_xprt *xprt = task->tk_xprt;
888 	struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
889 
890 	dprint_status(task);
891 
892 	task->tk_status = 0;
893 	task->tk_action = call_bind;
894 
895 	if (req->rq_buffer)
896 		return;
897 
898 	if (proc->p_proc != 0) {
899 		BUG_ON(proc->p_arglen == 0);
900 		if (proc->p_decode != NULL)
901 			BUG_ON(proc->p_replen == 0);
902 	}
903 
904 	/*
905 	 * Calculate the size (in quads) of the RPC call
906 	 * and reply headers, and convert both values
907 	 * to byte sizes.
908 	 */
909 	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
910 	req->rq_callsize <<= 2;
911 	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
912 	req->rq_rcvsize <<= 2;
913 
914 	req->rq_buffer = xprt->ops->buf_alloc(task,
915 					req->rq_callsize + req->rq_rcvsize);
916 	if (req->rq_buffer != NULL)
917 		return;
918 
919 	dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
920 
921 	if (RPC_IS_ASYNC(task) || !signalled()) {
922 		task->tk_action = call_allocate;
923 		rpc_delay(task, HZ>>4);
924 		return;
925 	}
926 
927 	rpc_exit(task, -ERESTARTSYS);
928 }
929 
930 static inline int
931 rpc_task_need_encode(struct rpc_task *task)
932 {
933 	return task->tk_rqstp->rq_snd_buf.len == 0;
934 }
935 
936 static inline void
937 rpc_task_force_reencode(struct rpc_task *task)
938 {
939 	task->tk_rqstp->rq_snd_buf.len = 0;
940 }
941 
942 static inline void
943 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
944 {
945 	buf->head[0].iov_base = start;
946 	buf->head[0].iov_len = len;
947 	buf->tail[0].iov_len = 0;
948 	buf->page_len = 0;
949 	buf->flags = 0;
950 	buf->len = 0;
951 	buf->buflen = len;
952 }
953 
954 /*
955  * 3.	Encode arguments of an RPC call
956  */
957 static void
958 rpc_xdr_encode(struct rpc_task *task)
959 {
960 	struct rpc_rqst	*req = task->tk_rqstp;
961 	kxdrproc_t	encode;
962 	__be32		*p;
963 
964 	dprint_status(task);
965 
966 	rpc_xdr_buf_init(&req->rq_snd_buf,
967 			 req->rq_buffer,
968 			 req->rq_callsize);
969 	rpc_xdr_buf_init(&req->rq_rcv_buf,
970 			 (char *)req->rq_buffer + req->rq_callsize,
971 			 req->rq_rcvsize);
972 
973 	p = rpc_encode_header(task);
974 	if (p == NULL) {
975 		printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
976 		rpc_exit(task, -EIO);
977 		return;
978 	}
979 
980 	encode = task->tk_msg.rpc_proc->p_encode;
981 	if (encode == NULL)
982 		return;
983 
984 	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
985 			task->tk_msg.rpc_argp);
986 }
987 
988 /*
989  * 4.	Get the server port number if not yet set
990  */
991 static void
992 call_bind(struct rpc_task *task)
993 {
994 	struct rpc_xprt *xprt = task->tk_xprt;
995 
996 	dprint_status(task);
997 
998 	task->tk_action = call_connect;
999 	if (!xprt_bound(xprt)) {
1000 		task->tk_action = call_bind_status;
1001 		task->tk_timeout = xprt->bind_timeout;
1002 		xprt->ops->rpcbind(task);
1003 	}
1004 }
1005 
1006 /*
1007  * 4a.	Sort out bind result
1008  */
1009 static void
1010 call_bind_status(struct rpc_task *task)
1011 {
1012 	int status = -EIO;
1013 
1014 	if (task->tk_status >= 0) {
1015 		dprint_status(task);
1016 		task->tk_status = 0;
1017 		task->tk_action = call_connect;
1018 		return;
1019 	}
1020 
1021 	switch (task->tk_status) {
1022 	case -ENOMEM:
1023 		dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1024 		rpc_delay(task, HZ >> 2);
1025 		goto retry_timeout;
1026 	case -EACCES:
1027 		dprintk("RPC: %5u remote rpcbind: RPC program/version "
1028 				"unavailable\n", task->tk_pid);
1029 		/* fail immediately if this is an RPC ping */
1030 		if (task->tk_msg.rpc_proc->p_proc == 0) {
1031 			status = -EOPNOTSUPP;
1032 			break;
1033 		}
1034 		rpc_delay(task, 3*HZ);
1035 		goto retry_timeout;
1036 	case -ETIMEDOUT:
1037 		dprintk("RPC: %5u rpcbind request timed out\n",
1038 				task->tk_pid);
1039 		goto retry_timeout;
1040 	case -EPFNOSUPPORT:
1041 		/* server doesn't support any rpcbind version we know of */
1042 		dprintk("RPC: %5u remote rpcbind service unavailable\n",
1043 				task->tk_pid);
1044 		break;
1045 	case -EPROTONOSUPPORT:
1046 		dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1047 				task->tk_pid);
1048 		task->tk_status = 0;
1049 		task->tk_action = call_bind;
1050 		return;
1051 	default:
1052 		dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1053 				task->tk_pid, -task->tk_status);
1054 	}
1055 
1056 	rpc_exit(task, status);
1057 	return;
1058 
1059 retry_timeout:
1060 	task->tk_action = call_timeout;
1061 }
1062 
1063 /*
1064  * 4b.	Connect to the RPC server
1065  */
1066 static void
1067 call_connect(struct rpc_task *task)
1068 {
1069 	struct rpc_xprt *xprt = task->tk_xprt;
1070 
1071 	dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1072 			task->tk_pid, xprt,
1073 			(xprt_connected(xprt) ? "is" : "is not"));
1074 
1075 	task->tk_action = call_transmit;
1076 	if (!xprt_connected(xprt)) {
1077 		task->tk_action = call_connect_status;
1078 		if (task->tk_status < 0)
1079 			return;
1080 		xprt_connect(task);
1081 	}
1082 }
1083 
1084 /*
1085  * 4c.	Sort out connect result
1086  */
1087 static void
1088 call_connect_status(struct rpc_task *task)
1089 {
1090 	struct rpc_clnt *clnt = task->tk_client;
1091 	int status = task->tk_status;
1092 
1093 	dprint_status(task);
1094 
1095 	task->tk_status = 0;
1096 	if (status >= 0 || status == -EAGAIN) {
1097 		clnt->cl_stats->netreconn++;
1098 		task->tk_action = call_transmit;
1099 		return;
1100 	}
1101 
1102 	switch (status) {
1103 		/* if soft mounted, test if we've timed out */
1104 	case -ETIMEDOUT:
1105 		task->tk_action = call_timeout;
1106 		break;
1107 	default:
1108 		rpc_exit(task, -EIO);
1109 	}
1110 }
1111 
1112 /*
1113  * 5.	Transmit the RPC request, and wait for reply
1114  */
1115 static void
1116 call_transmit(struct rpc_task *task)
1117 {
1118 	dprint_status(task);
1119 
1120 	task->tk_action = call_status;
1121 	if (task->tk_status < 0)
1122 		return;
1123 	task->tk_status = xprt_prepare_transmit(task);
1124 	if (task->tk_status != 0)
1125 		return;
1126 	task->tk_action = call_transmit_status;
1127 	/* Encode here so that rpcsec_gss can use correct sequence number. */
1128 	if (rpc_task_need_encode(task)) {
1129 		BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1130 		rpc_xdr_encode(task);
1131 		/* Did the encode result in an error condition? */
1132 		if (task->tk_status != 0) {
1133 			/* Was the error nonfatal? */
1134 			if (task->tk_status == -EAGAIN)
1135 				rpc_delay(task, HZ >> 4);
1136 			else
1137 				rpc_exit(task, task->tk_status);
1138 			return;
1139 		}
1140 	}
1141 	xprt_transmit(task);
1142 	if (task->tk_status < 0)
1143 		return;
1144 	/*
1145 	 * On success, ensure that we call xprt_end_transmit() before sleeping
1146 	 * in order to allow access to the socket to other RPC requests.
1147 	 */
1148 	call_transmit_status(task);
1149 	if (rpc_reply_expected(task))
1150 		return;
1151 	task->tk_action = rpc_exit_task;
1152 	rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1153 }
1154 
1155 /*
1156  * 5a.	Handle cleanup after a transmission
1157  */
1158 static void
1159 call_transmit_status(struct rpc_task *task)
1160 {
1161 	task->tk_action = call_status;
1162 	switch (task->tk_status) {
1163 	case -EAGAIN:
1164 		break;
1165 	default:
1166 		xprt_end_transmit(task);
1167 		/*
1168 		 * Special cases: if we've been waiting on the
1169 		 * socket's write_space() callback, or if the
1170 		 * socket just returned a connection error,
1171 		 * then hold onto the transport lock.
1172 		 */
1173 	case -ECONNREFUSED:
1174 	case -ECONNRESET:
1175 	case -ENOTCONN:
1176 	case -EHOSTDOWN:
1177 	case -EHOSTUNREACH:
1178 	case -ENETUNREACH:
1179 	case -EPIPE:
1180 		rpc_task_force_reencode(task);
1181 	}
1182 }
1183 
1184 #if defined(CONFIG_NFS_V4_1)
1185 /*
1186  * 5b.	Send the backchannel RPC reply.  On error, drop the reply.  In
1187  * addition, disconnect on connectivity errors.
1188  */
1189 static void
1190 call_bc_transmit(struct rpc_task *task)
1191 {
1192 	struct rpc_rqst *req = task->tk_rqstp;
1193 
1194 	BUG_ON(task->tk_status != 0);
1195 	task->tk_status = xprt_prepare_transmit(task);
1196 	if (task->tk_status == -EAGAIN) {
1197 		/*
1198 		 * Could not reserve the transport. Try again after the
1199 		 * transport is released.
1200 		 */
1201 		task->tk_status = 0;
1202 		task->tk_action = call_bc_transmit;
1203 		return;
1204 	}
1205 
1206 	task->tk_action = rpc_exit_task;
1207 	if (task->tk_status < 0) {
1208 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1209 			"error: %d\n", task->tk_status);
1210 		return;
1211 	}
1212 
1213 	xprt_transmit(task);
1214 	xprt_end_transmit(task);
1215 	dprint_status(task);
1216 	switch (task->tk_status) {
1217 	case 0:
1218 		/* Success */
1219 		break;
1220 	case -EHOSTDOWN:
1221 	case -EHOSTUNREACH:
1222 	case -ENETUNREACH:
1223 	case -ETIMEDOUT:
1224 		/*
1225 		 * Problem reaching the server.  Disconnect and let the
1226 		 * forechannel reestablish the connection.  The server will
1227 		 * have to retransmit the backchannel request and we'll
1228 		 * reprocess it.  Since these ops are idempotent, there's no
1229 		 * need to cache our reply at this time.
1230 		 */
1231 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1232 			"error: %d\n", task->tk_status);
1233 		xprt_conditional_disconnect(task->tk_xprt,
1234 			req->rq_connect_cookie);
1235 		break;
1236 	default:
1237 		/*
1238 		 * We were unable to reply and will have to drop the
1239 		 * request.  The server should reconnect and retransmit.
1240 		 */
1241 		BUG_ON(task->tk_status == -EAGAIN);
1242 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1243 			"error: %d\n", task->tk_status);
1244 		break;
1245 	}
1246 	rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1247 }
1248 #endif /* CONFIG_NFS_V4_1 */
1249 
1250 /*
1251  * 6.	Sort out the RPC call status
1252  */
1253 static void
1254 call_status(struct rpc_task *task)
1255 {
1256 	struct rpc_clnt	*clnt = task->tk_client;
1257 	struct rpc_rqst	*req = task->tk_rqstp;
1258 	int		status;
1259 
1260 	if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1261 		task->tk_status = req->rq_reply_bytes_recvd;
1262 
1263 	dprint_status(task);
1264 
1265 	status = task->tk_status;
1266 	if (status >= 0) {
1267 		task->tk_action = call_decode;
1268 		return;
1269 	}
1270 
1271 	task->tk_status = 0;
1272 	switch(status) {
1273 	case -EHOSTDOWN:
1274 	case -EHOSTUNREACH:
1275 	case -ENETUNREACH:
1276 		/*
1277 		 * Delay any retries for 3 seconds, then handle as if it
1278 		 * were a timeout.
1279 		 */
1280 		rpc_delay(task, 3*HZ);
1281 	case -ETIMEDOUT:
1282 		task->tk_action = call_timeout;
1283 		if (task->tk_client->cl_discrtry)
1284 			xprt_conditional_disconnect(task->tk_xprt,
1285 					req->rq_connect_cookie);
1286 		break;
1287 	case -ECONNRESET:
1288 	case -ECONNREFUSED:
1289 		rpc_force_rebind(clnt);
1290 		rpc_delay(task, 3*HZ);
1291 	case -EPIPE:
1292 	case -ENOTCONN:
1293 		task->tk_action = call_bind;
1294 		break;
1295 	case -EAGAIN:
1296 		task->tk_action = call_transmit;
1297 		break;
1298 	case -EIO:
1299 		/* shutdown or soft timeout */
1300 		rpc_exit(task, status);
1301 		break;
1302 	default:
1303 		if (clnt->cl_chatty)
1304 			printk("%s: RPC call returned error %d\n",
1305 			       clnt->cl_protname, -status);
1306 		rpc_exit(task, status);
1307 	}
1308 }
1309 
1310 /*
1311  * 6a.	Handle RPC timeout
1312  * 	We do not release the request slot, so we keep using the
1313  *	same XID for all retransmits.
1314  */
1315 static void
1316 call_timeout(struct rpc_task *task)
1317 {
1318 	struct rpc_clnt	*clnt = task->tk_client;
1319 
1320 	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1321 		dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1322 		goto retry;
1323 	}
1324 
1325 	dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1326 	task->tk_timeouts++;
1327 
1328 	if (RPC_IS_SOFT(task)) {
1329 		if (clnt->cl_chatty)
1330 			printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1331 				clnt->cl_protname, clnt->cl_server);
1332 		rpc_exit(task, -EIO);
1333 		return;
1334 	}
1335 
1336 	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1337 		task->tk_flags |= RPC_CALL_MAJORSEEN;
1338 		if (clnt->cl_chatty)
1339 			printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1340 			clnt->cl_protname, clnt->cl_server);
1341 	}
1342 	rpc_force_rebind(clnt);
1343 	/*
1344 	 * Did our request time out due to an RPCSEC_GSS out-of-sequence
1345 	 * event? RFC2203 requires the server to drop all such requests.
1346 	 */
1347 	rpcauth_invalcred(task);
1348 
1349 retry:
1350 	clnt->cl_stats->rpcretrans++;
1351 	task->tk_action = call_bind;
1352 	task->tk_status = 0;
1353 }
1354 
1355 /*
1356  * 7.	Decode the RPC reply
1357  */
1358 static void
1359 call_decode(struct rpc_task *task)
1360 {
1361 	struct rpc_clnt	*clnt = task->tk_client;
1362 	struct rpc_rqst	*req = task->tk_rqstp;
1363 	kxdrproc_t	decode = task->tk_msg.rpc_proc->p_decode;
1364 	__be32		*p;
1365 
1366 	dprintk("RPC: %5u call_decode (status %d)\n",
1367 			task->tk_pid, task->tk_status);
1368 
1369 	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1370 		if (clnt->cl_chatty)
1371 			printk(KERN_NOTICE "%s: server %s OK\n",
1372 				clnt->cl_protname, clnt->cl_server);
1373 		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1374 	}
1375 
1376 	/*
1377 	 * Ensure that we see all writes made by xprt_complete_rqst()
1378 	 * before it changed req->rq_reply_bytes_recvd.
1379 	 */
1380 	smp_rmb();
1381 	req->rq_rcv_buf.len = req->rq_private_buf.len;
1382 
1383 	/* Check that the softirq receive buffer is valid */
1384 	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1385 				sizeof(req->rq_rcv_buf)) != 0);
1386 
1387 	if (req->rq_rcv_buf.len < 12) {
1388 		if (!RPC_IS_SOFT(task)) {
1389 			task->tk_action = call_bind;
1390 			clnt->cl_stats->rpcretrans++;
1391 			goto out_retry;
1392 		}
1393 		dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1394 				clnt->cl_protname, task->tk_status);
1395 		task->tk_action = call_timeout;
1396 		goto out_retry;
1397 	}
1398 
1399 	p = rpc_verify_header(task);
1400 	if (IS_ERR(p)) {
1401 		if (p == ERR_PTR(-EAGAIN))
1402 			goto out_retry;
1403 		return;
1404 	}
1405 
1406 	task->tk_action = rpc_exit_task;
1407 
1408 	if (decode) {
1409 		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1410 						      task->tk_msg.rpc_resp);
1411 	}
1412 	dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1413 			task->tk_status);
1414 	return;
1415 out_retry:
1416 	task->tk_status = 0;
1417 	/* Note: rpc_verify_header() may have freed the RPC slot */
1418 	if (task->tk_rqstp == req) {
1419 		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
1420 		if (task->tk_client->cl_discrtry)
1421 			xprt_conditional_disconnect(task->tk_xprt,
1422 					req->rq_connect_cookie);
1423 	}
1424 }
1425 
1426 /*
1427  * 8.	Refresh the credentials if rejected by the server
1428  */
1429 static void
1430 call_refresh(struct rpc_task *task)
1431 {
1432 	dprint_status(task);
1433 
1434 	task->tk_action = call_refreshresult;
1435 	task->tk_status = 0;
1436 	task->tk_client->cl_stats->rpcauthrefresh++;
1437 	rpcauth_refreshcred(task);
1438 }
1439 
1440 /*
1441  * 8a.	Process the results of a credential refresh
1442  */
1443 static void
1444 call_refreshresult(struct rpc_task *task)
1445 {
1446 	int status = task->tk_status;
1447 
1448 	dprint_status(task);
1449 
1450 	task->tk_status = 0;
1451 	task->tk_action = call_reserve;
1452 	if (status >= 0 && rpcauth_uptodatecred(task))
1453 		return;
1454 	if (status == -EACCES) {
1455 		rpc_exit(task, -EACCES);
1456 		return;
1457 	}
1458 	task->tk_action = call_refresh;
1459 	if (status != -ETIMEDOUT)
1460 		rpc_delay(task, 3*HZ);
1461 	return;
1462 }
1463 
1464 static __be32 *
1465 rpc_encode_header(struct rpc_task *task)
1466 {
1467 	struct rpc_clnt *clnt = task->tk_client;
1468 	struct rpc_rqst	*req = task->tk_rqstp;
1469 	__be32		*p = req->rq_svec[0].iov_base;
1470 
1471 	/* FIXME: check buffer size? */
1472 
1473 	p = xprt_skip_transport_header(task->tk_xprt, p);
1474 	*p++ = req->rq_xid;		/* XID */
1475 	*p++ = htonl(RPC_CALL);		/* CALL */
1476 	*p++ = htonl(RPC_VERSION);	/* RPC version */
1477 	*p++ = htonl(clnt->cl_prog);	/* program number */
1478 	*p++ = htonl(clnt->cl_vers);	/* program version */
1479 	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
1480 	p = rpcauth_marshcred(task, p);
1481 	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1482 	return p;
1483 }
1484 
1485 static __be32 *
1486 rpc_verify_header(struct rpc_task *task)
1487 {
1488 	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1489 	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1490 	__be32	*p = iov->iov_base;
1491 	u32 n;
1492 	int error = -EACCES;
1493 
1494 	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1495 		/* RFC-1014 says that the representation of XDR data must be a
1496 		 * multiple of four bytes
1497 		 * - if it isn't pointer subtraction in the NFS client may give
1498 		 *   undefined results
1499 		 */
1500 		dprintk("RPC: %5u %s: XDR representation not a multiple of"
1501 		       " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1502 		       task->tk_rqstp->rq_rcv_buf.len);
1503 		goto out_eio;
1504 	}
1505 	if ((len -= 3) < 0)
1506 		goto out_overflow;
1507 
1508 	p += 1; /* skip XID */
1509 	if ((n = ntohl(*p++)) != RPC_REPLY) {
1510 		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1511 			task->tk_pid, __func__, n);
1512 		goto out_garbage;
1513 	}
1514 
1515 	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1516 		if (--len < 0)
1517 			goto out_overflow;
1518 		switch ((n = ntohl(*p++))) {
1519 			case RPC_AUTH_ERROR:
1520 				break;
1521 			case RPC_MISMATCH:
1522 				dprintk("RPC: %5u %s: RPC call version "
1523 						"mismatch!\n",
1524 						task->tk_pid, __func__);
1525 				error = -EPROTONOSUPPORT;
1526 				goto out_err;
1527 			default:
1528 				dprintk("RPC: %5u %s: RPC call rejected, "
1529 						"unknown error: %x\n",
1530 						task->tk_pid, __func__, n);
1531 				goto out_eio;
1532 		}
1533 		if (--len < 0)
1534 			goto out_overflow;
1535 		switch ((n = ntohl(*p++))) {
1536 		case RPC_AUTH_REJECTEDCRED:
1537 		case RPC_AUTH_REJECTEDVERF:
1538 		case RPCSEC_GSS_CREDPROBLEM:
1539 		case RPCSEC_GSS_CTXPROBLEM:
1540 			if (!task->tk_cred_retry)
1541 				break;
1542 			task->tk_cred_retry--;
1543 			dprintk("RPC: %5u %s: retry stale creds\n",
1544 					task->tk_pid, __func__);
1545 			rpcauth_invalcred(task);
1546 			/* Ensure we obtain a new XID! */
1547 			xprt_release(task);
1548 			task->tk_action = call_refresh;
1549 			goto out_retry;
1550 		case RPC_AUTH_BADCRED:
1551 		case RPC_AUTH_BADVERF:
1552 			/* possibly garbled cred/verf? */
1553 			if (!task->tk_garb_retry)
1554 				break;
1555 			task->tk_garb_retry--;
1556 			dprintk("RPC: %5u %s: retry garbled creds\n",
1557 					task->tk_pid, __func__);
1558 			task->tk_action = call_bind;
1559 			goto out_retry;
1560 		case RPC_AUTH_TOOWEAK:
1561 			printk(KERN_NOTICE "RPC: server %s requires stronger "
1562 			       "authentication.\n", task->tk_client->cl_server);
1563 			break;
1564 		default:
1565 			dprintk("RPC: %5u %s: unknown auth error: %x\n",
1566 					task->tk_pid, __func__, n);
1567 			error = -EIO;
1568 		}
1569 		dprintk("RPC: %5u %s: call rejected %d\n",
1570 				task->tk_pid, __func__, n);
1571 		goto out_err;
1572 	}
1573 	if (!(p = rpcauth_checkverf(task, p))) {
1574 		dprintk("RPC: %5u %s: auth check failed\n",
1575 				task->tk_pid, __func__);
1576 		goto out_garbage;		/* bad verifier, retry */
1577 	}
1578 	len = p - (__be32 *)iov->iov_base - 1;
1579 	if (len < 0)
1580 		goto out_overflow;
1581 	switch ((n = ntohl(*p++))) {
1582 	case RPC_SUCCESS:
1583 		return p;
1584 	case RPC_PROG_UNAVAIL:
1585 		dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1586 				task->tk_pid, __func__,
1587 				(unsigned int)task->tk_client->cl_prog,
1588 				task->tk_client->cl_server);
1589 		error = -EPFNOSUPPORT;
1590 		goto out_err;
1591 	case RPC_PROG_MISMATCH:
1592 		dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1593 				"server %s\n", task->tk_pid, __func__,
1594 				(unsigned int)task->tk_client->cl_prog,
1595 				(unsigned int)task->tk_client->cl_vers,
1596 				task->tk_client->cl_server);
1597 		error = -EPROTONOSUPPORT;
1598 		goto out_err;
1599 	case RPC_PROC_UNAVAIL:
1600 		dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1601 				"version %u on server %s\n",
1602 				task->tk_pid, __func__,
1603 				rpc_proc_name(task),
1604 				task->tk_client->cl_prog,
1605 				task->tk_client->cl_vers,
1606 				task->tk_client->cl_server);
1607 		error = -EOPNOTSUPP;
1608 		goto out_err;
1609 	case RPC_GARBAGE_ARGS:
1610 		dprintk("RPC: %5u %s: server saw garbage\n",
1611 				task->tk_pid, __func__);
1612 		break;			/* retry */
1613 	default:
1614 		dprintk("RPC: %5u %s: server accept status: %x\n",
1615 				task->tk_pid, __func__, n);
1616 		/* Also retry */
1617 	}
1618 
1619 out_garbage:
1620 	task->tk_client->cl_stats->rpcgarbage++;
1621 	if (task->tk_garb_retry) {
1622 		task->tk_garb_retry--;
1623 		dprintk("RPC: %5u %s: retrying\n",
1624 				task->tk_pid, __func__);
1625 		task->tk_action = call_bind;
1626 out_retry:
1627 		return ERR_PTR(-EAGAIN);
1628 	}
1629 out_eio:
1630 	error = -EIO;
1631 out_err:
1632 	rpc_exit(task, error);
1633 	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1634 			__func__, error);
1635 	return ERR_PTR(error);
1636 out_overflow:
1637 	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1638 			__func__);
1639 	goto out_garbage;
1640 }
1641 
1642 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1643 {
1644 	return 0;
1645 }
1646 
1647 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1648 {
1649 	return 0;
1650 }
1651 
1652 static struct rpc_procinfo rpcproc_null = {
1653 	.p_encode = rpcproc_encode_null,
1654 	.p_decode = rpcproc_decode_null,
1655 };
1656 
1657 static int rpc_ping(struct rpc_clnt *clnt, int flags)
1658 {
1659 	struct rpc_message msg = {
1660 		.rpc_proc = &rpcproc_null,
1661 	};
1662 	int err;
1663 	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1664 	err = rpc_call_sync(clnt, &msg, flags);
1665 	put_rpccred(msg.rpc_cred);
1666 	return err;
1667 }
1668 
1669 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1670 {
1671 	struct rpc_message msg = {
1672 		.rpc_proc = &rpcproc_null,
1673 		.rpc_cred = cred,
1674 	};
1675 	struct rpc_task_setup task_setup_data = {
1676 		.rpc_client = clnt,
1677 		.rpc_message = &msg,
1678 		.callback_ops = &rpc_default_ops,
1679 		.flags = flags,
1680 	};
1681 	return rpc_run_task(&task_setup_data);
1682 }
1683 EXPORT_SYMBOL_GPL(rpc_call_null);
1684 
1685 #ifdef RPC_DEBUG
1686 static void rpc_show_header(void)
1687 {
1688 	printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1689 		"-timeout ---ops--\n");
1690 }
1691 
1692 static void rpc_show_task(const struct rpc_clnt *clnt,
1693 			  const struct rpc_task *task)
1694 {
1695 	const char *rpc_waitq = "none";
1696 	char *p, action[KSYM_SYMBOL_LEN];
1697 
1698 	if (RPC_IS_QUEUED(task))
1699 		rpc_waitq = rpc_qname(task->tk_waitqueue);
1700 
1701 	/* map tk_action pointer to a function name; then trim off
1702 	 * the "+0x0 [sunrpc]" */
1703 	sprint_symbol(action, (unsigned long)task->tk_action);
1704 	p = strchr(action, '+');
1705 	if (p)
1706 		*p = '\0';
1707 
1708 	printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%s q:%s\n",
1709 		task->tk_pid, task->tk_flags, task->tk_status,
1710 		clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1711 		clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1712 		action, rpc_waitq);
1713 }
1714 
1715 void rpc_show_tasks(void)
1716 {
1717 	struct rpc_clnt *clnt;
1718 	struct rpc_task *task;
1719 	int header = 0;
1720 
1721 	spin_lock(&rpc_client_lock);
1722 	list_for_each_entry(clnt, &all_clients, cl_clients) {
1723 		spin_lock(&clnt->cl_lock);
1724 		list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1725 			if (!header) {
1726 				rpc_show_header();
1727 				header++;
1728 			}
1729 			rpc_show_task(clnt, task);
1730 		}
1731 		spin_unlock(&clnt->cl_lock);
1732 	}
1733 	spin_unlock(&rpc_client_lock);
1734 }
1735 #endif
1736