Merge git://git.infradead.org/mtd-2.6
[linux-2.6] / fs / lockd / clntproc.c
1 /*
2  * linux/fs/lockd/clntproc.c
3  *
4  * RPC procedures for the client side NLM implementation
5  *
6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7  */
8
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/errno.h>
12 #include <linux/fs.h>
13 #include <linux/nfs_fs.h>
14 #include <linux/utsname.h>
15 #include <linux/freezer.h>
16 #include <linux/sunrpc/clnt.h>
17 #include <linux/sunrpc/svc.h>
18 #include <linux/lockd/lockd.h>
19 #include <linux/lockd/sm_inter.h>
20
21 #define NLMDBG_FACILITY         NLMDBG_CLIENT
22 #define NLMCLNT_GRACE_WAIT      (5*HZ)
23 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
24 #define NLMCLNT_MAX_RETRIES     3
25
26 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
27 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
28 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
29 static int      nlm_stat_to_errno(__be32 stat);
30 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
31 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
32
33 static const struct rpc_call_ops nlmclnt_unlock_ops;
34 static const struct rpc_call_ops nlmclnt_cancel_ops;
35
36 /*
37  * Cookie counter for NLM requests
38  */
39 static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
40
41 void nlmclnt_next_cookie(struct nlm_cookie *c)
42 {
43         u32     cookie = atomic_inc_return(&nlm_cookie);
44
45         memcpy(c->data, &cookie, 4);
46         c->len=4;
47 }
48
49 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
50 {
51         atomic_inc(&lockowner->count);
52         return lockowner;
53 }
54
55 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
56 {
57         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
58                 return;
59         list_del(&lockowner->list);
60         spin_unlock(&lockowner->host->h_lock);
61         nlm_release_host(lockowner->host);
62         kfree(lockowner);
63 }
64
65 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
66 {
67         struct nlm_lockowner *lockowner;
68         list_for_each_entry(lockowner, &host->h_lockowners, list) {
69                 if (lockowner->pid == pid)
70                         return -EBUSY;
71         }
72         return 0;
73 }
74
75 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
76 {
77         uint32_t res;
78         do {
79                 res = host->h_pidcount++;
80         } while (nlm_pidbusy(host, res) < 0);
81         return res;
82 }
83
84 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
85 {
86         struct nlm_lockowner *lockowner;
87         list_for_each_entry(lockowner, &host->h_lockowners, list) {
88                 if (lockowner->owner != owner)
89                         continue;
90                 return nlm_get_lockowner(lockowner);
91         }
92         return NULL;
93 }
94
95 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
96 {
97         struct nlm_lockowner *res, *new = NULL;
98
99         spin_lock(&host->h_lock);
100         res = __nlm_find_lockowner(host, owner);
101         if (res == NULL) {
102                 spin_unlock(&host->h_lock);
103                 new = kmalloc(sizeof(*new), GFP_KERNEL);
104                 spin_lock(&host->h_lock);
105                 res = __nlm_find_lockowner(host, owner);
106                 if (res == NULL && new != NULL) {
107                         res = new;
108                         atomic_set(&new->count, 1);
109                         new->owner = owner;
110                         new->pid = __nlm_alloc_pid(host);
111                         new->host = nlm_get_host(host);
112                         list_add(&new->list, &host->h_lockowners);
113                         new = NULL;
114                 }
115         }
116         spin_unlock(&host->h_lock);
117         kfree(new);
118         return res;
119 }
120
121 /*
122  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
123  */
124 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
125 {
126         struct nlm_args *argp = &req->a_args;
127         struct nlm_lock *lock = &argp->lock;
128
129         nlmclnt_next_cookie(&argp->cookie);
130         argp->state   = nsm_local_state;
131         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
132         lock->caller  = utsname()->nodename;
133         lock->oh.data = req->a_owner;
134         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
135                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
136                                 utsname()->nodename);
137         lock->svid = fl->fl_u.nfs_fl.owner->pid;
138         lock->fl.fl_start = fl->fl_start;
139         lock->fl.fl_end = fl->fl_end;
140         lock->fl.fl_type = fl->fl_type;
141 }
142
143 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
144 {
145         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
146 }
147
148 /**
149  * nlmclnt_proc - Perform a single client-side lock request
150  * @host: address of a valid nlm_host context representing the NLM server
151  * @cmd: fcntl-style file lock operation to perform
152  * @fl: address of arguments for the lock operation
153  *
154  */
155 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
156 {
157         struct nlm_rqst         *call;
158         int                     status;
159
160         nlm_get_host(host);
161         call = nlm_alloc_call(host);
162         if (call == NULL)
163                 return -ENOMEM;
164
165         nlmclnt_locks_init_private(fl, host);
166         /* Set up the argument struct */
167         nlmclnt_setlockargs(call, fl);
168
169         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
170                 if (fl->fl_type != F_UNLCK) {
171                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
172                         status = nlmclnt_lock(call, fl);
173                 } else
174                         status = nlmclnt_unlock(call, fl);
175         } else if (IS_GETLK(cmd))
176                 status = nlmclnt_test(call, fl);
177         else
178                 status = -EINVAL;
179
180         fl->fl_ops->fl_release_private(fl);
181         fl->fl_ops = NULL;
182
183         dprintk("lockd: clnt proc returns %d\n", status);
184         return status;
185 }
186 EXPORT_SYMBOL_GPL(nlmclnt_proc);
187
188 /*
189  * Allocate an NLM RPC call struct
190  *
191  * Note: the caller must hold a reference to host. In case of failure,
192  * this reference will be released.
193  */
194 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
195 {
196         struct nlm_rqst *call;
197
198         for(;;) {
199                 call = kzalloc(sizeof(*call), GFP_KERNEL);
200                 if (call != NULL) {
201                         atomic_set(&call->a_count, 1);
202                         locks_init_lock(&call->a_args.lock.fl);
203                         locks_init_lock(&call->a_res.lock.fl);
204                         call->a_host = host;
205                         return call;
206                 }
207                 if (signalled())
208                         break;
209                 printk("nlm_alloc_call: failed, waiting for memory\n");
210                 schedule_timeout_interruptible(5*HZ);
211         }
212         nlm_release_host(host);
213         return NULL;
214 }
215
216 void nlm_release_call(struct nlm_rqst *call)
217 {
218         if (!atomic_dec_and_test(&call->a_count))
219                 return;
220         nlm_release_host(call->a_host);
221         nlmclnt_release_lockargs(call);
222         kfree(call);
223 }
224
225 static void nlmclnt_rpc_release(void *data)
226 {
227         nlm_release_call(data);
228 }
229
230 static int nlm_wait_on_grace(wait_queue_head_t *queue)
231 {
232         DEFINE_WAIT(wait);
233         int status = -EINTR;
234
235         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
236         if (!signalled ()) {
237                 schedule_timeout(NLMCLNT_GRACE_WAIT);
238                 try_to_freeze();
239                 if (!signalled ())
240                         status = 0;
241         }
242         finish_wait(queue, &wait);
243         return status;
244 }
245
246 /*
247  * Generic NLM call
248  */
249 static int
250 nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
251 {
252         struct nlm_host *host = req->a_host;
253         struct rpc_clnt *clnt;
254         struct nlm_args *argp = &req->a_args;
255         struct nlm_res  *resp = &req->a_res;
256         struct rpc_message msg = {
257                 .rpc_argp       = argp,
258                 .rpc_resp       = resp,
259                 .rpc_cred       = cred,
260         };
261         int             status;
262
263         dprintk("lockd: call procedure %d on %s\n",
264                         (int)proc, host->h_name);
265
266         do {
267                 if (host->h_reclaiming && !argp->reclaim)
268                         goto in_grace_period;
269
270                 /* If we have no RPC client yet, create one. */
271                 if ((clnt = nlm_bind_host(host)) == NULL)
272                         return -ENOLCK;
273                 msg.rpc_proc = &clnt->cl_procinfo[proc];
274
275                 /* Perform the RPC call. If an error occurs, try again */
276                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
277                         dprintk("lockd: rpc_call returned error %d\n", -status);
278                         switch (status) {
279                         case -EPROTONOSUPPORT:
280                                 status = -EINVAL;
281                                 break;
282                         case -ECONNREFUSED:
283                         case -ETIMEDOUT:
284                         case -ENOTCONN:
285                                 nlm_rebind_host(host);
286                                 status = -EAGAIN;
287                                 break;
288                         case -ERESTARTSYS:
289                                 return signalled () ? -EINTR : status;
290                         default:
291                                 break;
292                         }
293                         break;
294                 } else
295                 if (resp->status == nlm_lck_denied_grace_period) {
296                         dprintk("lockd: server in grace period\n");
297                         if (argp->reclaim) {
298                                 printk(KERN_WARNING
299                                      "lockd: spurious grace period reject?!\n");
300                                 return -ENOLCK;
301                         }
302                 } else {
303                         if (!argp->reclaim) {
304                                 /* We appear to be out of the grace period */
305                                 wake_up_all(&host->h_gracewait);
306                         }
307                         dprintk("lockd: server returns status %d\n", resp->status);
308                         return 0;       /* Okay, call complete */
309                 }
310
311 in_grace_period:
312                 /*
313                  * The server has rebooted and appears to be in the grace
314                  * period during which locks are only allowed to be
315                  * reclaimed.
316                  * We can only back off and try again later.
317                  */
318                 status = nlm_wait_on_grace(&host->h_gracewait);
319         } while (status == 0);
320
321         return status;
322 }
323
324 /*
325  * Generic NLM call, async version.
326  */
327 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
328 {
329         struct nlm_host *host = req->a_host;
330         struct rpc_clnt *clnt;
331         struct rpc_task_setup task_setup_data = {
332                 .rpc_message = msg,
333                 .callback_ops = tk_ops,
334                 .callback_data = req,
335                 .flags = RPC_TASK_ASYNC,
336         };
337
338         dprintk("lockd: call procedure %d on %s (async)\n",
339                         (int)proc, host->h_name);
340
341         /* If we have no RPC client yet, create one. */
342         clnt = nlm_bind_host(host);
343         if (clnt == NULL)
344                 goto out_err;
345         msg->rpc_proc = &clnt->cl_procinfo[proc];
346         task_setup_data.rpc_client = clnt;
347
348         /* bootstrap and kick off the async RPC call */
349         return rpc_run_task(&task_setup_data);
350 out_err:
351         tk_ops->rpc_release(req);
352         return ERR_PTR(-ENOLCK);
353 }
354
355 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
356 {
357         struct rpc_task *task;
358
359         task = __nlm_async_call(req, proc, msg, tk_ops);
360         if (IS_ERR(task))
361                 return PTR_ERR(task);
362         rpc_put_task(task);
363         return 0;
364 }
365
366 /*
367  * NLM asynchronous call.
368  */
369 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
370 {
371         struct rpc_message msg = {
372                 .rpc_argp       = &req->a_args,
373                 .rpc_resp       = &req->a_res,
374         };
375         return nlm_do_async_call(req, proc, &msg, tk_ops);
376 }
377
378 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
379 {
380         struct rpc_message msg = {
381                 .rpc_argp       = &req->a_res,
382         };
383         return nlm_do_async_call(req, proc, &msg, tk_ops);
384 }
385
386 /*
387  * NLM client asynchronous call.
388  *
389  * Note that although the calls are asynchronous, and are therefore
390  *      guaranteed to complete, we still always attempt to wait for
391  *      completion in order to be able to correctly track the lock
392  *      state.
393  */
394 static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
395 {
396         struct rpc_message msg = {
397                 .rpc_argp       = &req->a_args,
398                 .rpc_resp       = &req->a_res,
399                 .rpc_cred       = cred,
400         };
401         struct rpc_task *task;
402         int err;
403
404         task = __nlm_async_call(req, proc, &msg, tk_ops);
405         if (IS_ERR(task))
406                 return PTR_ERR(task);
407         err = rpc_wait_for_completion_task(task);
408         rpc_put_task(task);
409         return err;
410 }
411
412 /*
413  * TEST for the presence of a conflicting lock
414  */
415 static int
416 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
417 {
418         int     status;
419
420         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
421         if (status < 0)
422                 goto out;
423
424         switch (req->a_res.status) {
425                 case nlm_granted:
426                         fl->fl_type = F_UNLCK;
427                         break;
428                 case nlm_lck_denied:
429                         /*
430                          * Report the conflicting lock back to the application.
431                          */
432                         fl->fl_start = req->a_res.lock.fl.fl_start;
433                         fl->fl_end = req->a_res.lock.fl.fl_start;
434                         fl->fl_type = req->a_res.lock.fl.fl_type;
435                         fl->fl_pid = 0;
436                         break;
437                 default:
438                         status = nlm_stat_to_errno(req->a_res.status);
439         }
440 out:
441         nlm_release_call(req);
442         return status;
443 }
444
445 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
446 {
447         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
448         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
449         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
450 }
451
452 static void nlmclnt_locks_release_private(struct file_lock *fl)
453 {
454         list_del(&fl->fl_u.nfs_fl.list);
455         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
456 }
457
458 static struct file_lock_operations nlmclnt_lock_ops = {
459         .fl_copy_lock = nlmclnt_locks_copy_lock,
460         .fl_release_private = nlmclnt_locks_release_private,
461 };
462
463 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
464 {
465         BUG_ON(fl->fl_ops != NULL);
466         fl->fl_u.nfs_fl.state = 0;
467         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
468         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
469         fl->fl_ops = &nlmclnt_lock_ops;
470 }
471
472 static int do_vfs_lock(struct file_lock *fl)
473 {
474         int res = 0;
475         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
476                 case FL_POSIX:
477                         res = posix_lock_file_wait(fl->fl_file, fl);
478                         break;
479                 case FL_FLOCK:
480                         res = flock_lock_file_wait(fl->fl_file, fl);
481                         break;
482                 default:
483                         BUG();
484         }
485         return res;
486 }
487
488 /*
489  * LOCK: Try to create a lock
490  *
491  *                      Programmer Harassment Alert
492  *
493  * When given a blocking lock request in a sync RPC call, the HPUX lockd
494  * will faithfully return LCK_BLOCKED but never cares to notify us when
495  * the lock could be granted. This way, our local process could hang
496  * around forever waiting for the callback.
497  *
498  *  Solution A: Implement busy-waiting
499  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
500  *
501  * For now I am implementing solution A, because I hate the idea of
502  * re-implementing lockd for a third time in two months. The async
503  * calls shouldn't be too hard to do, however.
504  *
505  * This is one of the lovely things about standards in the NFS area:
506  * they're so soft and squishy you can't really blame HP for doing this.
507  */
508 static int
509 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
510 {
511         struct rpc_cred *cred = nfs_file_cred(fl->fl_file);
512         struct nlm_host *host = req->a_host;
513         struct nlm_res  *resp = &req->a_res;
514         struct nlm_wait *block = NULL;
515         unsigned char fl_flags = fl->fl_flags;
516         unsigned char fl_type;
517         int status = -ENOLCK;
518
519         if (nsm_monitor(host) < 0) {
520                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
521                                         host->h_name);
522                 goto out;
523         }
524         fl->fl_flags |= FL_ACCESS;
525         status = do_vfs_lock(fl);
526         fl->fl_flags = fl_flags;
527         if (status < 0)
528                 goto out;
529
530         block = nlmclnt_prepare_block(host, fl);
531 again:
532         /*
533          * Initialise resp->status to a valid non-zero value,
534          * since 0 == nlm_lck_granted
535          */
536         resp->status = nlm_lck_blocked;
537         for(;;) {
538                 /* Reboot protection */
539                 fl->fl_u.nfs_fl.state = host->h_state;
540                 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
541                 if (status < 0)
542                         break;
543                 /* Did a reclaimer thread notify us of a server reboot? */
544                 if (resp->status ==  nlm_lck_denied_grace_period)
545                         continue;
546                 if (resp->status != nlm_lck_blocked)
547                         break;
548                 /* Wait on an NLM blocking lock */
549                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
550                 if (status < 0)
551                         break;
552                 if (resp->status != nlm_lck_blocked)
553                         break;
554         }
555
556         /* if we were interrupted while blocking, then cancel the lock request
557          * and exit
558          */
559         if (resp->status == nlm_lck_blocked) {
560                 if (!req->a_args.block)
561                         goto out_unlock;
562                 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
563                         goto out_unblock;
564         }
565
566         if (resp->status == nlm_granted) {
567                 down_read(&host->h_rwsem);
568                 /* Check whether or not the server has rebooted */
569                 if (fl->fl_u.nfs_fl.state != host->h_state) {
570                         up_read(&host->h_rwsem);
571                         goto again;
572                 }
573                 /* Ensure the resulting lock will get added to granted list */
574                 fl->fl_flags |= FL_SLEEP;
575                 if (do_vfs_lock(fl) < 0)
576                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
577                 up_read(&host->h_rwsem);
578                 fl->fl_flags = fl_flags;
579                 status = 0;
580         }
581         if (status < 0)
582                 goto out_unlock;
583         status = nlm_stat_to_errno(resp->status);
584 out_unblock:
585         nlmclnt_finish_block(block);
586 out:
587         nlm_release_call(req);
588         return status;
589 out_unlock:
590         /* Fatal error: ensure that we remove the lock altogether */
591         dprintk("lockd: lock attempt ended in fatal error.\n"
592                 "       Attempting to unlock.\n");
593         nlmclnt_finish_block(block);
594         fl_type = fl->fl_type;
595         fl->fl_type = F_UNLCK;
596         down_read(&host->h_rwsem);
597         do_vfs_lock(fl);
598         up_read(&host->h_rwsem);
599         fl->fl_type = fl_type;
600         fl->fl_flags = fl_flags;
601         nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
602         return status;
603 }
604
605 /*
606  * RECLAIM: Try to reclaim a lock
607  */
608 int
609 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
610 {
611         struct nlm_rqst reqst, *req;
612         int             status;
613
614         req = &reqst;
615         memset(req, 0, sizeof(*req));
616         locks_init_lock(&req->a_args.lock.fl);
617         locks_init_lock(&req->a_res.lock.fl);
618         req->a_host  = host;
619         req->a_flags = 0;
620
621         /* Set up the argument struct */
622         nlmclnt_setlockargs(req, fl);
623         req->a_args.reclaim = 1;
624
625         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
626         if (status >= 0 && req->a_res.status == nlm_granted)
627                 return 0;
628
629         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
630                                 "(errno %d, status %d)\n", fl->fl_pid,
631                                 status, ntohl(req->a_res.status));
632
633         /*
634          * FIXME: This is a serious failure. We can
635          *
636          *  a.  Ignore the problem
637          *  b.  Send the owning process some signal (Linux doesn't have
638          *      SIGLOST, though...)
639          *  c.  Retry the operation
640          *
641          * Until someone comes up with a simple implementation
642          * for b or c, I'll choose option a.
643          */
644
645         return -ENOLCK;
646 }
647
648 /*
649  * UNLOCK: remove an existing lock
650  */
651 static int
652 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
653 {
654         struct nlm_host *host = req->a_host;
655         struct nlm_res  *resp = &req->a_res;
656         int status;
657         unsigned char fl_flags = fl->fl_flags;
658
659         /*
660          * Note: the server is supposed to either grant us the unlock
661          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
662          * case, we want to unlock.
663          */
664         fl->fl_flags |= FL_EXISTS;
665         down_read(&host->h_rwsem);
666         status = do_vfs_lock(fl);
667         up_read(&host->h_rwsem);
668         fl->fl_flags = fl_flags;
669         if (status == -ENOENT) {
670                 status = 0;
671                 goto out;
672         }
673
674         atomic_inc(&req->a_count);
675         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
676                         NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
677         if (status < 0)
678                 goto out;
679
680         if (resp->status == nlm_granted)
681                 goto out;
682
683         if (resp->status != nlm_lck_denied_nolocks)
684                 printk("lockd: unexpected unlock status: %d\n", resp->status);
685         /* What to do now? I'm out of my depth... */
686         status = -ENOLCK;
687 out:
688         nlm_release_call(req);
689         return status;
690 }
691
692 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
693 {
694         struct nlm_rqst *req = data;
695         u32 status = ntohl(req->a_res.status);
696
697         if (RPC_ASSASSINATED(task))
698                 goto die;
699
700         if (task->tk_status < 0) {
701                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
702                 goto retry_rebind;
703         }
704         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
705                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
706                 goto retry_unlock;
707         }
708         if (status != NLM_LCK_GRANTED)
709                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
710 die:
711         return;
712  retry_rebind:
713         nlm_rebind_host(req->a_host);
714  retry_unlock:
715         rpc_restart_call(task);
716 }
717
718 static const struct rpc_call_ops nlmclnt_unlock_ops = {
719         .rpc_call_done = nlmclnt_unlock_callback,
720         .rpc_release = nlmclnt_rpc_release,
721 };
722
723 /*
724  * Cancel a blocked lock request.
725  * We always use an async RPC call for this in order not to hang a
726  * process that has been Ctrl-C'ed.
727  */
728 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
729 {
730         struct nlm_rqst *req;
731         int status;
732
733         dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
734                 "       Attempting to cancel lock.\n");
735
736         req = nlm_alloc_call(nlm_get_host(host));
737         if (!req)
738                 return -ENOMEM;
739         req->a_flags = RPC_TASK_ASYNC;
740
741         nlmclnt_setlockargs(req, fl);
742         req->a_args.block = block;
743
744         atomic_inc(&req->a_count);
745         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
746                         NLMPROC_CANCEL, &nlmclnt_cancel_ops);
747         if (status == 0 && req->a_res.status == nlm_lck_denied)
748                 status = -ENOLCK;
749         nlm_release_call(req);
750         return status;
751 }
752
753 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
754 {
755         struct nlm_rqst *req = data;
756         u32 status = ntohl(req->a_res.status);
757
758         if (RPC_ASSASSINATED(task))
759                 goto die;
760
761         if (task->tk_status < 0) {
762                 dprintk("lockd: CANCEL call error %d, retrying.\n",
763                                         task->tk_status);
764                 goto retry_cancel;
765         }
766
767         dprintk("lockd: cancel status %u (task %u)\n",
768                         status, task->tk_pid);
769
770         switch (status) {
771         case NLM_LCK_GRANTED:
772         case NLM_LCK_DENIED_GRACE_PERIOD:
773         case NLM_LCK_DENIED:
774                 /* Everything's good */
775                 break;
776         case NLM_LCK_DENIED_NOLOCKS:
777                 dprintk("lockd: CANCEL failed (server has no locks)\n");
778                 goto retry_cancel;
779         default:
780                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
781                         status);
782         }
783
784 die:
785         return;
786
787 retry_cancel:
788         /* Don't ever retry more than 3 times */
789         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
790                 goto die;
791         nlm_rebind_host(req->a_host);
792         rpc_restart_call(task);
793         rpc_delay(task, 30 * HZ);
794 }
795
796 static const struct rpc_call_ops nlmclnt_cancel_ops = {
797         .rpc_call_done = nlmclnt_cancel_callback,
798         .rpc_release = nlmclnt_rpc_release,
799 };
800
801 /*
802  * Convert an NLM status code to a generic kernel errno
803  */
804 static int
805 nlm_stat_to_errno(__be32 status)
806 {
807         switch(ntohl(status)) {
808         case NLM_LCK_GRANTED:
809                 return 0;
810         case NLM_LCK_DENIED:
811                 return -EAGAIN;
812         case NLM_LCK_DENIED_NOLOCKS:
813         case NLM_LCK_DENIED_GRACE_PERIOD:
814                 return -ENOLCK;
815         case NLM_LCK_BLOCKED:
816                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
817                 return -ENOLCK;
818 #ifdef CONFIG_LOCKD_V4
819         case NLM_DEADLCK:
820                 return -EDEADLK;
821         case NLM_ROFS:
822                 return -EROFS;
823         case NLM_STALE_FH:
824                 return -ESTALE;
825         case NLM_FBIG:
826                 return -EOVERFLOW;
827         case NLM_FAILED:
828                 return -ENOLCK;
829 #endif
830         }
831         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
832         return -ENOLCK;
833 }