SUNRPC: Fix dentry refcounting issues with users of rpc_pipefs
[linux-2.6] / net / sunrpc / clnt.c
1 /*
2  *  linux/net/sunrpc/clnt.c
3  *
4  *  This file contains the high-level RPC interface.
5  *  It is modeled as a finite state machine to support both synchronous
6  *  and asynchronous requests.
7  *
8  *  -   RPC header generation and argument serialization.
9  *  -   Credential refresh.
10  *  -   TCP connect handling.
11  *  -   Retry of operation when it is suspected the operation failed because
12  *      of uid squashing on the server, or when the credentials were stale
13  *      and need to be refreshed, or when a packet was damaged in transit.
14  *      This may be have to be moved to the VFS layer.
15  *
16  *  NB: BSD uses a more intelligent approach to guessing when a request
17  *  or reply has been lost by keeping the RTO estimate for each procedure.
18  *  We currently make do with a constant timeout value.
19  *
20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
22  */
23
24 #include <asm/system.h>
25
26 #include <linux/module.h>
27 #include <linux/types.h>
28 #include <linux/mm.h>
29 #include <linux/slab.h>
30 #include <linux/utsname.h>
31 #include <linux/workqueue.h>
32
33 #include <linux/sunrpc/clnt.h>
34 #include <linux/sunrpc/rpc_pipe_fs.h>
35 #include <linux/sunrpc/metrics.h>
36
37
38 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
39
40 #ifdef RPC_DEBUG
41 # define RPCDBG_FACILITY        RPCDBG_CALL
42 #endif
43
44 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
45
46
47 static void     call_start(struct rpc_task *task);
48 static void     call_reserve(struct rpc_task *task);
49 static void     call_reserveresult(struct rpc_task *task);
50 static void     call_allocate(struct rpc_task *task);
51 static void     call_encode(struct rpc_task *task);
52 static void     call_decode(struct rpc_task *task);
53 static void     call_bind(struct rpc_task *task);
54 static void     call_bind_status(struct rpc_task *task);
55 static void     call_transmit(struct rpc_task *task);
56 static void     call_status(struct rpc_task *task);
57 static void     call_transmit_status(struct rpc_task *task);
58 static void     call_refresh(struct rpc_task *task);
59 static void     call_refreshresult(struct rpc_task *task);
60 static void     call_timeout(struct rpc_task *task);
61 static void     call_connect(struct rpc_task *task);
62 static void     call_connect_status(struct rpc_task *task);
63 static u32 *    call_header(struct rpc_task *task);
64 static u32 *    call_verify(struct rpc_task *task);
65
66
67 static int
68 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
69 {
70         static uint32_t clntid;
71         int error;
72
73         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
74         clnt->cl_dentry = ERR_PTR(-ENOENT);
75         if (dir_name == NULL)
76                 return 0;
77
78         clnt->cl_vfsmnt = rpc_get_mount();
79         if (IS_ERR(clnt->cl_vfsmnt))
80                 return PTR_ERR(clnt->cl_vfsmnt);
81
82         for (;;) {
83                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
84                                 "%s/clnt%x", dir_name,
85                                 (unsigned int)clntid++);
86                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
87                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
88                 if (!IS_ERR(clnt->cl_dentry))
89                         return 0;
90                 error = PTR_ERR(clnt->cl_dentry);
91                 if (error != -EEXIST) {
92                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
93                                         clnt->cl_pathname, error);
94                         rpc_put_mount();
95                         return error;
96                 }
97         }
98 }
99
100 /*
101  * Create an RPC client
102  * FIXME: This should also take a flags argument (as in task->tk_flags).
103  * It's called (among others) from pmap_create_client, which may in
104  * turn be called by an async task. In this case, rpciod should not be
105  * made to sleep too long.
106  */
107 struct rpc_clnt *
108 rpc_new_client(struct rpc_xprt *xprt, char *servname,
109                   struct rpc_program *program, u32 vers,
110                   rpc_authflavor_t flavor)
111 {
112         struct rpc_version      *version;
113         struct rpc_clnt         *clnt = NULL;
114         struct rpc_auth         *auth;
115         int err;
116         int len;
117
118         dprintk("RPC: creating %s client for %s (xprt %p)\n",
119                 program->name, servname, xprt);
120
121         err = -EINVAL;
122         if (!xprt)
123                 goto out_no_xprt;
124         if (vers >= program->nrvers || !(version = program->version[vers]))
125                 goto out_err;
126
127         err = -ENOMEM;
128         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
129         if (!clnt)
130                 goto out_err;
131         atomic_set(&clnt->cl_users, 0);
132         atomic_set(&clnt->cl_count, 1);
133         clnt->cl_parent = clnt;
134
135         clnt->cl_server = clnt->cl_inline_name;
136         len = strlen(servname) + 1;
137         if (len > sizeof(clnt->cl_inline_name)) {
138                 char *buf = kmalloc(len, GFP_KERNEL);
139                 if (buf != 0)
140                         clnt->cl_server = buf;
141                 else
142                         len = sizeof(clnt->cl_inline_name);
143         }
144         strlcpy(clnt->cl_server, servname, len);
145
146         clnt->cl_xprt     = xprt;
147         clnt->cl_procinfo = version->procs;
148         clnt->cl_maxproc  = version->nrprocs;
149         clnt->cl_protname = program->name;
150         clnt->cl_pmap     = &clnt->cl_pmap_default;
151         clnt->cl_port     = xprt->addr.sin_port;
152         clnt->cl_prog     = program->number;
153         clnt->cl_vers     = version->number;
154         clnt->cl_prot     = xprt->prot;
155         clnt->cl_stats    = program->stats;
156         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
157         rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
158
159         if (!clnt->cl_port)
160                 clnt->cl_autobind = 1;
161
162         clnt->cl_rtt = &clnt->cl_rtt_default;
163         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
164
165         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
166         if (err < 0)
167                 goto out_no_path;
168
169         auth = rpcauth_create(flavor, clnt);
170         if (IS_ERR(auth)) {
171                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
172                                 flavor);
173                 err = PTR_ERR(auth);
174                 goto out_no_auth;
175         }
176
177         /* save the nodename */
178         clnt->cl_nodelen = strlen(system_utsname.nodename);
179         if (clnt->cl_nodelen > UNX_MAXNODENAME)
180                 clnt->cl_nodelen = UNX_MAXNODENAME;
181         memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
182         return clnt;
183
184 out_no_auth:
185         if (!IS_ERR(clnt->cl_dentry)) {
186                 rpc_rmdir(clnt->cl_dentry);
187                 rpc_put_mount();
188         }
189 out_no_path:
190         if (clnt->cl_server != clnt->cl_inline_name)
191                 kfree(clnt->cl_server);
192         kfree(clnt);
193 out_err:
194         xprt_destroy(xprt);
195 out_no_xprt:
196         return ERR_PTR(err);
197 }
198
199 /**
200  * Create an RPC client
201  * @xprt - pointer to xprt struct
202  * @servname - name of server
203  * @info - rpc_program
204  * @version - rpc_program version
205  * @authflavor - rpc_auth flavour to use
206  *
207  * Creates an RPC client structure, then pings the server in order to
208  * determine if it is up, and if it supports this program and version.
209  *
210  * This function should never be called by asynchronous tasks such as
211  * the portmapper.
212  */
213 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
214                 struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
215 {
216         struct rpc_clnt *clnt;
217         int err;
218         
219         clnt = rpc_new_client(xprt, servname, info, version, authflavor);
220         if (IS_ERR(clnt))
221                 return clnt;
222         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
223         if (err == 0)
224                 return clnt;
225         rpc_shutdown_client(clnt);
226         return ERR_PTR(err);
227 }
228
229 /*
230  * This function clones the RPC client structure. It allows us to share the
231  * same transport while varying parameters such as the authentication
232  * flavour.
233  */
234 struct rpc_clnt *
235 rpc_clone_client(struct rpc_clnt *clnt)
236 {
237         struct rpc_clnt *new;
238
239         new = kmalloc(sizeof(*new), GFP_KERNEL);
240         if (!new)
241                 goto out_no_clnt;
242         memcpy(new, clnt, sizeof(*new));
243         atomic_set(&new->cl_count, 1);
244         atomic_set(&new->cl_users, 0);
245         new->cl_parent = clnt;
246         atomic_inc(&clnt->cl_count);
247         /* Duplicate portmapper */
248         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
249         /* Turn off autobind on clones */
250         new->cl_autobind = 0;
251         new->cl_oneshot = 0;
252         new->cl_dead = 0;
253         if (!IS_ERR(new->cl_dentry))
254                 dget(new->cl_dentry);
255         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
256         if (new->cl_auth)
257                 atomic_inc(&new->cl_auth->au_count);
258         new->cl_pmap            = &new->cl_pmap_default;
259         new->cl_metrics         = rpc_alloc_iostats(clnt);
260         return new;
261 out_no_clnt:
262         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
263         return ERR_PTR(-ENOMEM);
264 }
265
266 /*
267  * Properly shut down an RPC client, terminating all outstanding
268  * requests. Note that we must be certain that cl_oneshot and
269  * cl_dead are cleared, or else the client would be destroyed
270  * when the last task releases it.
271  */
272 int
273 rpc_shutdown_client(struct rpc_clnt *clnt)
274 {
275         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
276                         clnt->cl_protname, clnt->cl_server,
277                         atomic_read(&clnt->cl_users));
278
279         while (atomic_read(&clnt->cl_users) > 0) {
280                 /* Don't let rpc_release_client destroy us */
281                 clnt->cl_oneshot = 0;
282                 clnt->cl_dead = 0;
283                 rpc_killall_tasks(clnt);
284                 wait_event_timeout(destroy_wait,
285                         !atomic_read(&clnt->cl_users), 1*HZ);
286         }
287
288         if (atomic_read(&clnt->cl_users) < 0) {
289                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
290                                 clnt, atomic_read(&clnt->cl_users));
291 #ifdef RPC_DEBUG
292                 rpc_show_tasks();
293 #endif
294                 BUG();
295         }
296
297         return rpc_destroy_client(clnt);
298 }
299
300 /*
301  * Delete an RPC client
302  */
303 int
304 rpc_destroy_client(struct rpc_clnt *clnt)
305 {
306         if (!atomic_dec_and_test(&clnt->cl_count))
307                 return 1;
308         BUG_ON(atomic_read(&clnt->cl_users) != 0);
309
310         dprintk("RPC: destroying %s client for %s\n",
311                         clnt->cl_protname, clnt->cl_server);
312         if (clnt->cl_auth) {
313                 rpcauth_destroy(clnt->cl_auth);
314                 clnt->cl_auth = NULL;
315         }
316         if (clnt->cl_parent != clnt) {
317                 if (!IS_ERR(clnt->cl_dentry))
318                         dput(clnt->cl_dentry);
319                 rpc_destroy_client(clnt->cl_parent);
320                 goto out_free;
321         }
322         if (!IS_ERR(clnt->cl_dentry)) {
323                 rpc_rmdir(clnt->cl_dentry);
324                 rpc_put_mount();
325         }
326         if (clnt->cl_xprt) {
327                 xprt_destroy(clnt->cl_xprt);
328                 clnt->cl_xprt = NULL;
329         }
330         if (clnt->cl_server != clnt->cl_inline_name)
331                 kfree(clnt->cl_server);
332 out_free:
333         rpc_free_iostats(clnt->cl_metrics);
334         clnt->cl_metrics = NULL;
335         kfree(clnt);
336         return 0;
337 }
338
339 /*
340  * Release an RPC client
341  */
342 void
343 rpc_release_client(struct rpc_clnt *clnt)
344 {
345         dprintk("RPC:      rpc_release_client(%p, %d)\n",
346                                 clnt, atomic_read(&clnt->cl_users));
347
348         if (!atomic_dec_and_test(&clnt->cl_users))
349                 return;
350         wake_up(&destroy_wait);
351         if (clnt->cl_oneshot || clnt->cl_dead)
352                 rpc_destroy_client(clnt);
353 }
354
355 /**
356  * rpc_bind_new_program - bind a new RPC program to an existing client
357  * @old - old rpc_client
358  * @program - rpc program to set
359  * @vers - rpc program version
360  *
361  * Clones the rpc client and sets up a new RPC program. This is mainly
362  * of use for enabling different RPC programs to share the same transport.
363  * The Sun NFSv2/v3 ACL protocol can do this.
364  */
365 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
366                                       struct rpc_program *program,
367                                       int vers)
368 {
369         struct rpc_clnt *clnt;
370         struct rpc_version *version;
371         int err;
372
373         BUG_ON(vers >= program->nrvers || !program->version[vers]);
374         version = program->version[vers];
375         clnt = rpc_clone_client(old);
376         if (IS_ERR(clnt))
377                 goto out;
378         clnt->cl_procinfo = version->procs;
379         clnt->cl_maxproc  = version->nrprocs;
380         clnt->cl_protname = program->name;
381         clnt->cl_prog     = program->number;
382         clnt->cl_vers     = version->number;
383         clnt->cl_stats    = program->stats;
384         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
385         if (err != 0) {
386                 rpc_shutdown_client(clnt);
387                 clnt = ERR_PTR(err);
388         }
389 out:    
390         return clnt;
391 }
392
393 /*
394  * Default callback for async RPC calls
395  */
396 static void
397 rpc_default_callback(struct rpc_task *task, void *data)
398 {
399 }
400
401 static const struct rpc_call_ops rpc_default_ops = {
402         .rpc_call_done = rpc_default_callback,
403 };
404
405 /*
406  *      Export the signal mask handling for synchronous code that
407  *      sleeps on RPC calls
408  */
409 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
410  
411 static void rpc_save_sigmask(sigset_t *oldset, int intr)
412 {
413         unsigned long   sigallow = sigmask(SIGKILL);
414         sigset_t sigmask;
415
416         /* Block all signals except those listed in sigallow */
417         if (intr)
418                 sigallow |= RPC_INTR_SIGNALS;
419         siginitsetinv(&sigmask, sigallow);
420         sigprocmask(SIG_BLOCK, &sigmask, oldset);
421 }
422
423 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
424 {
425         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
426 }
427
428 static inline void rpc_restore_sigmask(sigset_t *oldset)
429 {
430         sigprocmask(SIG_SETMASK, oldset, NULL);
431 }
432
433 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
434 {
435         rpc_save_sigmask(oldset, clnt->cl_intr);
436 }
437
438 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
439 {
440         rpc_restore_sigmask(oldset);
441 }
442
443 /*
444  * New rpc_call implementation
445  */
446 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
447 {
448         struct rpc_task *task;
449         sigset_t        oldset;
450         int             status;
451
452         /* If this client is slain all further I/O fails */
453         if (clnt->cl_dead) 
454                 return -EIO;
455
456         BUG_ON(flags & RPC_TASK_ASYNC);
457
458         status = -ENOMEM;
459         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
460         if (task == NULL)
461                 goto out;
462
463         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
464         rpc_task_sigmask(task, &oldset);
465
466         rpc_call_setup(task, msg, 0);
467
468         /* Set up the call info struct and execute the task */
469         status = task->tk_status;
470         if (status == 0) {
471                 atomic_inc(&task->tk_count);
472                 status = rpc_execute(task);
473                 if (status == 0)
474                         status = task->tk_status;
475         }
476         rpc_restore_sigmask(&oldset);
477         rpc_release_task(task);
478 out:
479         return status;
480 }
481
482 /*
483  * New rpc_call implementation
484  */
485 int
486 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
487                const struct rpc_call_ops *tk_ops, void *data)
488 {
489         struct rpc_task *task;
490         sigset_t        oldset;
491         int             status;
492
493         /* If this client is slain all further I/O fails */
494         status = -EIO;
495         if (clnt->cl_dead) 
496                 goto out_release;
497
498         flags |= RPC_TASK_ASYNC;
499
500         /* Create/initialize a new RPC task */
501         status = -ENOMEM;
502         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
503                 goto out_release;
504
505         /* Mask signals on GSS_AUTH upcalls */
506         rpc_task_sigmask(task, &oldset);                
507
508         rpc_call_setup(task, msg, 0);
509
510         /* Set up the call info struct and execute the task */
511         status = task->tk_status;
512         if (status == 0)
513                 rpc_execute(task);
514         else
515                 rpc_release_task(task);
516
517         rpc_restore_sigmask(&oldset);           
518         return status;
519 out_release:
520         if (tk_ops->rpc_release != NULL)
521                 tk_ops->rpc_release(data);
522         return status;
523 }
524
525
526 void
527 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
528 {
529         task->tk_msg   = *msg;
530         task->tk_flags |= flags;
531         /* Bind the user cred */
532         if (task->tk_msg.rpc_cred != NULL)
533                 rpcauth_holdcred(task);
534         else
535                 rpcauth_bindcred(task);
536
537         if (task->tk_status == 0)
538                 task->tk_action = call_start;
539         else
540                 task->tk_action = rpc_exit_task;
541 }
542
543 void
544 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
545 {
546         struct rpc_xprt *xprt = clnt->cl_xprt;
547         if (xprt->ops->set_buffer_size)
548                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
549 }
550
551 /*
552  * Return size of largest payload RPC client can support, in bytes
553  *
554  * For stream transports, this is one RPC record fragment (see RFC
555  * 1831), as we don't support multi-record requests yet.  For datagram
556  * transports, this is the size of an IP packet minus the IP, UDP, and
557  * RPC header sizes.
558  */
559 size_t rpc_max_payload(struct rpc_clnt *clnt)
560 {
561         return clnt->cl_xprt->max_payload;
562 }
563 EXPORT_SYMBOL(rpc_max_payload);
564
565 /**
566  * rpc_force_rebind - force transport to check that remote port is unchanged
567  * @clnt: client to rebind
568  *
569  */
570 void rpc_force_rebind(struct rpc_clnt *clnt)
571 {
572         if (clnt->cl_autobind)
573                 clnt->cl_port = 0;
574 }
575 EXPORT_SYMBOL(rpc_force_rebind);
576
577 /*
578  * Restart an (async) RPC call. Usually called from within the
579  * exit handler.
580  */
581 void
582 rpc_restart_call(struct rpc_task *task)
583 {
584         if (RPC_ASSASSINATED(task))
585                 return;
586
587         task->tk_action = call_start;
588 }
589
590 /*
591  * 0.  Initial state
592  *
593  *     Other FSM states can be visited zero or more times, but
594  *     this state is visited exactly once for each RPC.
595  */
596 static void
597 call_start(struct rpc_task *task)
598 {
599         struct rpc_clnt *clnt = task->tk_client;
600
601         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
602                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
603                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
604
605         /* Increment call count */
606         task->tk_msg.rpc_proc->p_count++;
607         clnt->cl_stats->rpccnt++;
608         task->tk_action = call_reserve;
609 }
610
611 /*
612  * 1.   Reserve an RPC call slot
613  */
614 static void
615 call_reserve(struct rpc_task *task)
616 {
617         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
618
619         if (!rpcauth_uptodatecred(task)) {
620                 task->tk_action = call_refresh;
621                 return;
622         }
623
624         task->tk_status  = 0;
625         task->tk_action  = call_reserveresult;
626         xprt_reserve(task);
627 }
628
629 /*
630  * 1b.  Grok the result of xprt_reserve()
631  */
632 static void
633 call_reserveresult(struct rpc_task *task)
634 {
635         int status = task->tk_status;
636
637         dprintk("RPC: %4d call_reserveresult (status %d)\n",
638                                 task->tk_pid, task->tk_status);
639
640         /*
641          * After a call to xprt_reserve(), we must have either
642          * a request slot or else an error status.
643          */
644         task->tk_status = 0;
645         if (status >= 0) {
646                 if (task->tk_rqstp) {
647                         task->tk_action = call_allocate;
648                         return;
649                 }
650
651                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
652                                 __FUNCTION__, status);
653                 rpc_exit(task, -EIO);
654                 return;
655         }
656
657         /*
658          * Even though there was an error, we may have acquired
659          * a request slot somehow.  Make sure not to leak it.
660          */
661         if (task->tk_rqstp) {
662                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
663                                 __FUNCTION__, status);
664                 xprt_release(task);
665         }
666
667         switch (status) {
668         case -EAGAIN:   /* woken up; retry */
669                 task->tk_action = call_reserve;
670                 return;
671         case -EIO:      /* probably a shutdown */
672                 break;
673         default:
674                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
675                                 __FUNCTION__, status);
676                 break;
677         }
678         rpc_exit(task, status);
679 }
680
681 /*
682  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
683  *      (Note: buffer memory is freed in xprt_release).
684  */
685 static void
686 call_allocate(struct rpc_task *task)
687 {
688         struct rpc_rqst *req = task->tk_rqstp;
689         struct rpc_xprt *xprt = task->tk_xprt;
690         unsigned int    bufsiz;
691
692         dprintk("RPC: %4d call_allocate (status %d)\n", 
693                                 task->tk_pid, task->tk_status);
694         task->tk_action = call_bind;
695         if (req->rq_buffer)
696                 return;
697
698         /* FIXME: compute buffer requirements more exactly using
699          * auth->au_wslack */
700         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
701
702         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
703                 return;
704         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task); 
705
706         if (RPC_IS_ASYNC(task) || !signalled()) {
707                 xprt_release(task);
708                 task->tk_action = call_reserve;
709                 rpc_delay(task, HZ>>4);
710                 return;
711         }
712
713         rpc_exit(task, -ERESTARTSYS);
714 }
715
716 static inline int
717 rpc_task_need_encode(struct rpc_task *task)
718 {
719         return task->tk_rqstp->rq_snd_buf.len == 0;
720 }
721
722 static inline void
723 rpc_task_force_reencode(struct rpc_task *task)
724 {
725         task->tk_rqstp->rq_snd_buf.len = 0;
726 }
727
728 /*
729  * 3.   Encode arguments of an RPC call
730  */
731 static void
732 call_encode(struct rpc_task *task)
733 {
734         struct rpc_rqst *req = task->tk_rqstp;
735         struct xdr_buf *sndbuf = &req->rq_snd_buf;
736         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
737         unsigned int    bufsiz;
738         kxdrproc_t      encode;
739         u32             *p;
740
741         dprintk("RPC: %4d call_encode (status %d)\n", 
742                                 task->tk_pid, task->tk_status);
743
744         /* Default buffer setup */
745         bufsiz = req->rq_bufsize >> 1;
746         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
747         sndbuf->head[0].iov_len  = bufsiz;
748         sndbuf->tail[0].iov_len  = 0;
749         sndbuf->page_len         = 0;
750         sndbuf->len              = 0;
751         sndbuf->buflen           = bufsiz;
752         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
753         rcvbuf->head[0].iov_len  = bufsiz;
754         rcvbuf->tail[0].iov_len  = 0;
755         rcvbuf->page_len         = 0;
756         rcvbuf->len              = 0;
757         rcvbuf->buflen           = bufsiz;
758
759         /* Encode header and provided arguments */
760         encode = task->tk_msg.rpc_proc->p_encode;
761         if (!(p = call_header(task))) {
762                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
763                 rpc_exit(task, -EIO);
764                 return;
765         }
766         if (encode == NULL)
767                 return;
768
769         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
770                         task->tk_msg.rpc_argp);
771         if (task->tk_status == -ENOMEM) {
772                 /* XXX: Is this sane? */
773                 rpc_delay(task, 3*HZ);
774                 task->tk_status = -EAGAIN;
775         }
776 }
777
778 /*
779  * 4.   Get the server port number if not yet set
780  */
781 static void
782 call_bind(struct rpc_task *task)
783 {
784         struct rpc_clnt *clnt = task->tk_client;
785
786         dprintk("RPC: %4d call_bind (status %d)\n",
787                                 task->tk_pid, task->tk_status);
788
789         task->tk_action = call_connect;
790         if (!clnt->cl_port) {
791                 task->tk_action = call_bind_status;
792                 task->tk_timeout = task->tk_xprt->bind_timeout;
793                 rpc_getport(task, clnt);
794         }
795 }
796
797 /*
798  * 4a.  Sort out bind result
799  */
800 static void
801 call_bind_status(struct rpc_task *task)
802 {
803         int status = -EACCES;
804
805         if (task->tk_status >= 0) {
806                 dprintk("RPC: %4d call_bind_status (status %d)\n",
807                                         task->tk_pid, task->tk_status);
808                 task->tk_status = 0;
809                 task->tk_action = call_connect;
810                 return;
811         }
812
813         switch (task->tk_status) {
814         case -EACCES:
815                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
816                                 task->tk_pid);
817                 rpc_delay(task, 3*HZ);
818                 goto retry_bind;
819         case -ETIMEDOUT:
820                 dprintk("RPC: %4d rpcbind request timed out\n",
821                                 task->tk_pid);
822                 if (RPC_IS_SOFT(task)) {
823                         status = -EIO;
824                         break;
825                 }
826                 goto retry_bind;
827         case -EPFNOSUPPORT:
828                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
829                                 task->tk_pid);
830                 break;
831         case -EPROTONOSUPPORT:
832                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
833                                 task->tk_pid);
834                 break;
835         default:
836                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
837                                 task->tk_pid, -task->tk_status);
838                 status = -EIO;
839                 break;
840         }
841
842         rpc_exit(task, status);
843         return;
844
845 retry_bind:
846         task->tk_status = 0;
847         task->tk_action = call_bind;
848         return;
849 }
850
851 /*
852  * 4b.  Connect to the RPC server
853  */
854 static void
855 call_connect(struct rpc_task *task)
856 {
857         struct rpc_xprt *xprt = task->tk_xprt;
858
859         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
860                         task->tk_pid, xprt,
861                         (xprt_connected(xprt) ? "is" : "is not"));
862
863         task->tk_action = call_transmit;
864         if (!xprt_connected(xprt)) {
865                 task->tk_action = call_connect_status;
866                 if (task->tk_status < 0)
867                         return;
868                 xprt_connect(task);
869         }
870 }
871
872 /*
873  * 4c.  Sort out connect result
874  */
875 static void
876 call_connect_status(struct rpc_task *task)
877 {
878         struct rpc_clnt *clnt = task->tk_client;
879         int status = task->tk_status;
880
881         dprintk("RPC: %5u call_connect_status (status %d)\n", 
882                                 task->tk_pid, task->tk_status);
883
884         task->tk_status = 0;
885         if (status >= 0) {
886                 clnt->cl_stats->netreconn++;
887                 task->tk_action = call_transmit;
888                 return;
889         }
890
891         /* Something failed: remote service port may have changed */
892         rpc_force_rebind(clnt);
893
894         switch (status) {
895         case -ENOTCONN:
896         case -ETIMEDOUT:
897         case -EAGAIN:
898                 task->tk_action = call_bind;
899                 break;
900         default:
901                 rpc_exit(task, -EIO);
902                 break;
903         }
904 }
905
906 /*
907  * 5.   Transmit the RPC request, and wait for reply
908  */
909 static void
910 call_transmit(struct rpc_task *task)
911 {
912         dprintk("RPC: %4d call_transmit (status %d)\n", 
913                                 task->tk_pid, task->tk_status);
914
915         task->tk_action = call_status;
916         if (task->tk_status < 0)
917                 return;
918         task->tk_status = xprt_prepare_transmit(task);
919         if (task->tk_status != 0)
920                 return;
921         task->tk_action = call_transmit_status;
922         /* Encode here so that rpcsec_gss can use correct sequence number. */
923         if (rpc_task_need_encode(task)) {
924                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
925                 call_encode(task);
926                 /* Did the encode result in an error condition? */
927                 if (task->tk_status != 0)
928                         return;
929         }
930         xprt_transmit(task);
931         if (task->tk_status < 0)
932                 return;
933         /*
934          * On success, ensure that we call xprt_end_transmit() before sleeping
935          * in order to allow access to the socket to other RPC requests.
936          */
937         call_transmit_status(task);
938         if (task->tk_msg.rpc_proc->p_decode != NULL)
939                 return;
940         task->tk_action = rpc_exit_task;
941         rpc_wake_up_task(task);
942 }
943
944 /*
945  * 5a.  Handle cleanup after a transmission
946  */
947 static void
948 call_transmit_status(struct rpc_task *task)
949 {
950         task->tk_action = call_status;
951         /*
952          * Special case: if we've been waiting on the socket's write_space()
953          * callback, then don't call xprt_end_transmit().
954          */
955         if (task->tk_status == -EAGAIN)
956                 return;
957         xprt_end_transmit(task);
958         rpc_task_force_reencode(task);
959 }
960
961 /*
962  * 6.   Sort out the RPC call status
963  */
964 static void
965 call_status(struct rpc_task *task)
966 {
967         struct rpc_clnt *clnt = task->tk_client;
968         struct rpc_rqst *req = task->tk_rqstp;
969         int             status;
970
971         if (req->rq_received > 0 && !req->rq_bytes_sent)
972                 task->tk_status = req->rq_received;
973
974         dprintk("RPC: %4d call_status (status %d)\n", 
975                                 task->tk_pid, task->tk_status);
976
977         status = task->tk_status;
978         if (status >= 0) {
979                 task->tk_action = call_decode;
980                 return;
981         }
982
983         task->tk_status = 0;
984         switch(status) {
985         case -ETIMEDOUT:
986                 task->tk_action = call_timeout;
987                 break;
988         case -ECONNREFUSED:
989         case -ENOTCONN:
990                 rpc_force_rebind(clnt);
991                 task->tk_action = call_bind;
992                 break;
993         case -EAGAIN:
994                 task->tk_action = call_transmit;
995                 break;
996         case -EIO:
997                 /* shutdown or soft timeout */
998                 rpc_exit(task, status);
999                 break;
1000         default:
1001                 printk("%s: RPC call returned error %d\n",
1002                                clnt->cl_protname, -status);
1003                 rpc_exit(task, status);
1004                 break;
1005         }
1006 }
1007
1008 /*
1009  * 6a.  Handle RPC timeout
1010  *      We do not release the request slot, so we keep using the
1011  *      same XID for all retransmits.
1012  */
1013 static void
1014 call_timeout(struct rpc_task *task)
1015 {
1016         struct rpc_clnt *clnt = task->tk_client;
1017
1018         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1019                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1020                 goto retry;
1021         }
1022
1023         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1024         task->tk_timeouts++;
1025
1026         if (RPC_IS_SOFT(task)) {
1027                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1028                                 clnt->cl_protname, clnt->cl_server);
1029                 rpc_exit(task, -EIO);
1030                 return;
1031         }
1032
1033         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1034                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1035                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1036                         clnt->cl_protname, clnt->cl_server);
1037         }
1038         rpc_force_rebind(clnt);
1039
1040 retry:
1041         clnt->cl_stats->rpcretrans++;
1042         task->tk_action = call_bind;
1043         task->tk_status = 0;
1044 }
1045
1046 /*
1047  * 7.   Decode the RPC reply
1048  */
1049 static void
1050 call_decode(struct rpc_task *task)
1051 {
1052         struct rpc_clnt *clnt = task->tk_client;
1053         struct rpc_rqst *req = task->tk_rqstp;
1054         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1055         u32             *p;
1056
1057         dprintk("RPC: %4d call_decode (status %d)\n", 
1058                                 task->tk_pid, task->tk_status);
1059
1060         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1061                 printk(KERN_NOTICE "%s: server %s OK\n",
1062                         clnt->cl_protname, clnt->cl_server);
1063                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1064         }
1065
1066         if (task->tk_status < 12) {
1067                 if (!RPC_IS_SOFT(task)) {
1068                         task->tk_action = call_bind;
1069                         clnt->cl_stats->rpcretrans++;
1070                         goto out_retry;
1071                 }
1072                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1073                         clnt->cl_protname, task->tk_status);
1074                 rpc_exit(task, -EIO);
1075                 return;
1076         }
1077
1078         /*
1079          * Ensure that we see all writes made by xprt_complete_rqst()
1080          * before it changed req->rq_received.
1081          */
1082         smp_rmb();
1083         req->rq_rcv_buf.len = req->rq_private_buf.len;
1084
1085         /* Check that the softirq receive buffer is valid */
1086         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1087                                 sizeof(req->rq_rcv_buf)) != 0);
1088
1089         /* Verify the RPC header */
1090         p = call_verify(task);
1091         if (IS_ERR(p)) {
1092                 if (p == ERR_PTR(-EAGAIN))
1093                         goto out_retry;
1094                 return;
1095         }
1096
1097         task->tk_action = rpc_exit_task;
1098
1099         if (decode)
1100                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1101                                                       task->tk_msg.rpc_resp);
1102         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1103                                         task->tk_status);
1104         return;
1105 out_retry:
1106         req->rq_received = req->rq_private_buf.len = 0;
1107         task->tk_status = 0;
1108 }
1109
1110 /*
1111  * 8.   Refresh the credentials if rejected by the server
1112  */
1113 static void
1114 call_refresh(struct rpc_task *task)
1115 {
1116         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1117
1118         xprt_release(task);     /* Must do to obtain new XID */
1119         task->tk_action = call_refreshresult;
1120         task->tk_status = 0;
1121         task->tk_client->cl_stats->rpcauthrefresh++;
1122         rpcauth_refreshcred(task);
1123 }
1124
1125 /*
1126  * 8a.  Process the results of a credential refresh
1127  */
1128 static void
1129 call_refreshresult(struct rpc_task *task)
1130 {
1131         int status = task->tk_status;
1132         dprintk("RPC: %4d call_refreshresult (status %d)\n", 
1133                                 task->tk_pid, task->tk_status);
1134
1135         task->tk_status = 0;
1136         task->tk_action = call_reserve;
1137         if (status >= 0 && rpcauth_uptodatecred(task))
1138                 return;
1139         if (status == -EACCES) {
1140                 rpc_exit(task, -EACCES);
1141                 return;
1142         }
1143         task->tk_action = call_refresh;
1144         if (status != -ETIMEDOUT)
1145                 rpc_delay(task, 3*HZ);
1146         return;
1147 }
1148
1149 /*
1150  * Call header serialization
1151  */
1152 static u32 *
1153 call_header(struct rpc_task *task)
1154 {
1155         struct rpc_clnt *clnt = task->tk_client;
1156         struct rpc_rqst *req = task->tk_rqstp;
1157         u32             *p = req->rq_svec[0].iov_base;
1158
1159         /* FIXME: check buffer size? */
1160
1161         p = xprt_skip_transport_header(task->tk_xprt, p);
1162         *p++ = req->rq_xid;             /* XID */
1163         *p++ = htonl(RPC_CALL);         /* CALL */
1164         *p++ = htonl(RPC_VERSION);      /* RPC version */
1165         *p++ = htonl(clnt->cl_prog);    /* program number */
1166         *p++ = htonl(clnt->cl_vers);    /* program version */
1167         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1168         p = rpcauth_marshcred(task, p);
1169         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1170         return p;
1171 }
1172
1173 /*
1174  * Reply header verification
1175  */
1176 static u32 *
1177 call_verify(struct rpc_task *task)
1178 {
1179         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1180         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1181         u32     *p = iov->iov_base, n;
1182         int error = -EACCES;
1183
1184         if ((len -= 3) < 0)
1185                 goto out_overflow;
1186         p += 1; /* skip XID */
1187
1188         if ((n = ntohl(*p++)) != RPC_REPLY) {
1189                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1190                 goto out_garbage;
1191         }
1192         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1193                 if (--len < 0)
1194                         goto out_overflow;
1195                 switch ((n = ntohl(*p++))) {
1196                         case RPC_AUTH_ERROR:
1197                                 break;
1198                         case RPC_MISMATCH:
1199                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1200                                 error = -EPROTONOSUPPORT;
1201                                 goto out_err;
1202                         default:
1203                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1204                                 goto out_eio;
1205                 }
1206                 if (--len < 0)
1207                         goto out_overflow;
1208                 switch ((n = ntohl(*p++))) {
1209                 case RPC_AUTH_REJECTEDCRED:
1210                 case RPC_AUTH_REJECTEDVERF:
1211                 case RPCSEC_GSS_CREDPROBLEM:
1212                 case RPCSEC_GSS_CTXPROBLEM:
1213                         if (!task->tk_cred_retry)
1214                                 break;
1215                         task->tk_cred_retry--;
1216                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1217                                                         task->tk_pid);
1218                         rpcauth_invalcred(task);
1219                         task->tk_action = call_refresh;
1220                         goto out_retry;
1221                 case RPC_AUTH_BADCRED:
1222                 case RPC_AUTH_BADVERF:
1223                         /* possibly garbled cred/verf? */
1224                         if (!task->tk_garb_retry)
1225                                 break;
1226                         task->tk_garb_retry--;
1227                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1228                                                         task->tk_pid);
1229                         task->tk_action = call_bind;
1230                         goto out_retry;
1231                 case RPC_AUTH_TOOWEAK:
1232                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1233                                "authentication.\n", task->tk_client->cl_server);
1234                         break;
1235                 default:
1236                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1237                         error = -EIO;
1238                 }
1239                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1240                                                 task->tk_pid, n);
1241                 goto out_err;
1242         }
1243         if (!(p = rpcauth_checkverf(task, p))) {
1244                 printk(KERN_WARNING "call_verify: auth check failed\n");
1245                 goto out_garbage;               /* bad verifier, retry */
1246         }
1247         len = p - (u32 *)iov->iov_base - 1;
1248         if (len < 0)
1249                 goto out_overflow;
1250         switch ((n = ntohl(*p++))) {
1251         case RPC_SUCCESS:
1252                 return p;
1253         case RPC_PROG_UNAVAIL:
1254                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1255                                 (unsigned int)task->tk_client->cl_prog,
1256                                 task->tk_client->cl_server);
1257                 error = -EPFNOSUPPORT;
1258                 goto out_err;
1259         case RPC_PROG_MISMATCH:
1260                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1261                                 (unsigned int)task->tk_client->cl_prog,
1262                                 (unsigned int)task->tk_client->cl_vers,
1263                                 task->tk_client->cl_server);
1264                 error = -EPROTONOSUPPORT;
1265                 goto out_err;
1266         case RPC_PROC_UNAVAIL:
1267                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1268                                 task->tk_msg.rpc_proc,
1269                                 task->tk_client->cl_prog,
1270                                 task->tk_client->cl_vers,
1271                                 task->tk_client->cl_server);
1272                 error = -EOPNOTSUPP;
1273                 goto out_err;
1274         case RPC_GARBAGE_ARGS:
1275                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1276                 break;                  /* retry */
1277         default:
1278                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1279                 /* Also retry */
1280         }
1281
1282 out_garbage:
1283         task->tk_client->cl_stats->rpcgarbage++;
1284         if (task->tk_garb_retry) {
1285                 task->tk_garb_retry--;
1286                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1287                 task->tk_action = call_bind;
1288 out_retry:
1289                 return ERR_PTR(-EAGAIN);
1290         }
1291         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1292 out_eio:
1293         error = -EIO;
1294 out_err:
1295         rpc_exit(task, error);
1296         return ERR_PTR(error);
1297 out_overflow:
1298         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1299         goto out_garbage;
1300 }
1301
1302 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1303 {
1304         return 0;
1305 }
1306
1307 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1308 {
1309         return 0;
1310 }
1311
1312 static struct rpc_procinfo rpcproc_null = {
1313         .p_encode = rpcproc_encode_null,
1314         .p_decode = rpcproc_decode_null,
1315 };
1316
1317 int rpc_ping(struct rpc_clnt *clnt, int flags)
1318 {
1319         struct rpc_message msg = {
1320                 .rpc_proc = &rpcproc_null,
1321         };
1322         int err;
1323         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1324         err = rpc_call_sync(clnt, &msg, flags);
1325         put_rpccred(msg.rpc_cred);
1326         return err;
1327 }