Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney...
[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         lock_kernel();
228         nlm_release_call(data);
229         unlock_kernel();
230 }
231
232 static int nlm_wait_on_grace(wait_queue_head_t *queue)
233 {
234         DEFINE_WAIT(wait);
235         int status = -EINTR;
236
237         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
238         if (!signalled ()) {
239                 schedule_timeout(NLMCLNT_GRACE_WAIT);
240                 try_to_freeze();
241                 if (!signalled ())
242                         status = 0;
243         }
244         finish_wait(queue, &wait);
245         return status;
246 }
247
248 /*
249  * Generic NLM call
250  */
251 static int
252 nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
253 {
254         struct nlm_host *host = req->a_host;
255         struct rpc_clnt *clnt;
256         struct nlm_args *argp = &req->a_args;
257         struct nlm_res  *resp = &req->a_res;
258         struct rpc_message msg = {
259                 .rpc_argp       = argp,
260                 .rpc_resp       = resp,
261                 .rpc_cred       = cred,
262         };
263         int             status;
264
265         dprintk("lockd: call procedure %d on %s\n",
266                         (int)proc, host->h_name);
267
268         do {
269                 if (host->h_reclaiming && !argp->reclaim)
270                         goto in_grace_period;
271
272                 /* If we have no RPC client yet, create one. */
273                 if ((clnt = nlm_bind_host(host)) == NULL)
274                         return -ENOLCK;
275                 msg.rpc_proc = &clnt->cl_procinfo[proc];
276
277                 /* Perform the RPC call. If an error occurs, try again */
278                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
279                         dprintk("lockd: rpc_call returned error %d\n", -status);
280                         switch (status) {
281                         case -EPROTONOSUPPORT:
282                                 status = -EINVAL;
283                                 break;
284                         case -ECONNREFUSED:
285                         case -ETIMEDOUT:
286                         case -ENOTCONN:
287                                 nlm_rebind_host(host);
288                                 status = -EAGAIN;
289                                 break;
290                         case -ERESTARTSYS:
291                                 return signalled () ? -EINTR : status;
292                         default:
293                                 break;
294                         }
295                         break;
296                 } else
297                 if (resp->status == nlm_lck_denied_grace_period) {
298                         dprintk("lockd: server in grace period\n");
299                         if (argp->reclaim) {
300                                 printk(KERN_WARNING
301                                      "lockd: spurious grace period reject?!\n");
302                                 return -ENOLCK;
303                         }
304                 } else {
305                         if (!argp->reclaim) {
306                                 /* We appear to be out of the grace period */
307                                 wake_up_all(&host->h_gracewait);
308                         }
309                         dprintk("lockd: server returns status %d\n", resp->status);
310                         return 0;       /* Okay, call complete */
311                 }
312
313 in_grace_period:
314                 /*
315                  * The server has rebooted and appears to be in the grace
316                  * period during which locks are only allowed to be
317                  * reclaimed.
318                  * We can only back off and try again later.
319                  */
320                 status = nlm_wait_on_grace(&host->h_gracewait);
321         } while (status == 0);
322
323         return status;
324 }
325
326 /*
327  * Generic NLM call, async version.
328  */
329 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
330 {
331         struct nlm_host *host = req->a_host;
332         struct rpc_clnt *clnt;
333         struct rpc_task_setup task_setup_data = {
334                 .rpc_message = msg,
335                 .callback_ops = tk_ops,
336                 .callback_data = req,
337                 .flags = RPC_TASK_ASYNC,
338         };
339
340         dprintk("lockd: call procedure %d on %s (async)\n",
341                         (int)proc, host->h_name);
342
343         /* If we have no RPC client yet, create one. */
344         clnt = nlm_bind_host(host);
345         if (clnt == NULL)
346                 goto out_err;
347         msg->rpc_proc = &clnt->cl_procinfo[proc];
348         task_setup_data.rpc_client = clnt;
349
350         /* bootstrap and kick off the async RPC call */
351         return rpc_run_task(&task_setup_data);
352 out_err:
353         tk_ops->rpc_release(req);
354         return ERR_PTR(-ENOLCK);
355 }
356
357 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
358 {
359         struct rpc_task *task;
360
361         task = __nlm_async_call(req, proc, msg, tk_ops);
362         if (IS_ERR(task))
363                 return PTR_ERR(task);
364         rpc_put_task(task);
365         return 0;
366 }
367
368 /*
369  * NLM asynchronous call.
370  */
371 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
372 {
373         struct rpc_message msg = {
374                 .rpc_argp       = &req->a_args,
375                 .rpc_resp       = &req->a_res,
376         };
377         return nlm_do_async_call(req, proc, &msg, tk_ops);
378 }
379
380 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
381 {
382         struct rpc_message msg = {
383                 .rpc_argp       = &req->a_res,
384         };
385         return nlm_do_async_call(req, proc, &msg, tk_ops);
386 }
387
388 /*
389  * NLM client asynchronous call.
390  *
391  * Note that although the calls are asynchronous, and are therefore
392  *      guaranteed to complete, we still always attempt to wait for
393  *      completion in order to be able to correctly track the lock
394  *      state.
395  */
396 static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
397 {
398         struct rpc_message msg = {
399                 .rpc_argp       = &req->a_args,
400                 .rpc_resp       = &req->a_res,
401                 .rpc_cred       = cred,
402         };
403         struct rpc_task *task;
404         int err;
405
406         task = __nlm_async_call(req, proc, &msg, tk_ops);
407         if (IS_ERR(task))
408                 return PTR_ERR(task);
409         err = rpc_wait_for_completion_task(task);
410         rpc_put_task(task);
411         return err;
412 }
413
414 /*
415  * TEST for the presence of a conflicting lock
416  */
417 static int
418 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
419 {
420         int     status;
421
422         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
423         if (status < 0)
424                 goto out;
425
426         switch (req->a_res.status) {
427                 case nlm_granted:
428                         fl->fl_type = F_UNLCK;
429                         break;
430                 case nlm_lck_denied:
431                         /*
432                          * Report the conflicting lock back to the application.
433                          */
434                         fl->fl_start = req->a_res.lock.fl.fl_start;
435                         fl->fl_end = req->a_res.lock.fl.fl_end;
436                         fl->fl_type = req->a_res.lock.fl.fl_type;
437                         fl->fl_pid = 0;
438                         break;
439                 default:
440                         status = nlm_stat_to_errno(req->a_res.status);
441         }
442 out:
443         nlm_release_call(req);
444         return status;
445 }
446
447 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
448 {
449         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
450         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
451         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
452 }
453
454 static void nlmclnt_locks_release_private(struct file_lock *fl)
455 {
456         list_del(&fl->fl_u.nfs_fl.list);
457         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
458 }
459
460 static struct file_lock_operations nlmclnt_lock_ops = {
461         .fl_copy_lock = nlmclnt_locks_copy_lock,
462         .fl_release_private = nlmclnt_locks_release_private,
463 };
464
465 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
466 {
467         BUG_ON(fl->fl_ops != NULL);
468         fl->fl_u.nfs_fl.state = 0;
469         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
470         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
471         fl->fl_ops = &nlmclnt_lock_ops;
472 }
473
474 static int do_vfs_lock(struct file_lock *fl)
475 {
476         int res = 0;
477         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
478                 case FL_POSIX:
479                         res = posix_lock_file_wait(fl->fl_file, fl);
480                         break;
481                 case FL_FLOCK:
482                         res = flock_lock_file_wait(fl->fl_file, fl);
483                         break;
484                 default:
485                         BUG();
486         }
487         return res;
488 }
489
490 /*
491  * LOCK: Try to create a lock
492  *
493  *                      Programmer Harassment Alert
494  *
495  * When given a blocking lock request in a sync RPC call, the HPUX lockd
496  * will faithfully return LCK_BLOCKED but never cares to notify us when
497  * the lock could be granted. This way, our local process could hang
498  * around forever waiting for the callback.
499  *
500  *  Solution A: Implement busy-waiting
501  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
502  *
503  * For now I am implementing solution A, because I hate the idea of
504  * re-implementing lockd for a third time in two months. The async
505  * calls shouldn't be too hard to do, however.
506  *
507  * This is one of the lovely things about standards in the NFS area:
508  * they're so soft and squishy you can't really blame HP for doing this.
509  */
510 static int
511 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
512 {
513         struct rpc_cred *cred = nfs_file_cred(fl->fl_file);
514         struct nlm_host *host = req->a_host;
515         struct nlm_res  *resp = &req->a_res;
516         struct nlm_wait *block = NULL;
517         unsigned char fl_flags = fl->fl_flags;
518         unsigned char fl_type;
519         int status = -ENOLCK;
520
521         if (nsm_monitor(host) < 0) {
522                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
523                                         host->h_name);
524                 goto out;
525         }
526         fl->fl_flags |= FL_ACCESS;
527         status = do_vfs_lock(fl);
528         fl->fl_flags = fl_flags;
529         if (status < 0)
530                 goto out;
531
532         block = nlmclnt_prepare_block(host, fl);
533 again:
534         /*
535          * Initialise resp->status to a valid non-zero value,
536          * since 0 == nlm_lck_granted
537          */
538         resp->status = nlm_lck_blocked;
539         for(;;) {
540                 /* Reboot protection */
541                 fl->fl_u.nfs_fl.state = host->h_state;
542                 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
543                 if (status < 0)
544                         break;
545                 /* Did a reclaimer thread notify us of a server reboot? */
546                 if (resp->status ==  nlm_lck_denied_grace_period)
547                         continue;
548                 if (resp->status != nlm_lck_blocked)
549                         break;
550                 /* Wait on an NLM blocking lock */
551                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
552                 if (status < 0)
553                         break;
554                 if (resp->status != nlm_lck_blocked)
555                         break;
556         }
557
558         /* if we were interrupted while blocking, then cancel the lock request
559          * and exit
560          */
561         if (resp->status == nlm_lck_blocked) {
562                 if (!req->a_args.block)
563                         goto out_unlock;
564                 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
565                         goto out_unblock;
566         }
567
568         if (resp->status == nlm_granted) {
569                 down_read(&host->h_rwsem);
570                 /* Check whether or not the server has rebooted */
571                 if (fl->fl_u.nfs_fl.state != host->h_state) {
572                         up_read(&host->h_rwsem);
573                         goto again;
574                 }
575                 /* Ensure the resulting lock will get added to granted list */
576                 fl->fl_flags |= FL_SLEEP;
577                 if (do_vfs_lock(fl) < 0)
578                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
579                 up_read(&host->h_rwsem);
580                 fl->fl_flags = fl_flags;
581                 status = 0;
582         }
583         if (status < 0)
584                 goto out_unlock;
585         /*
586          * EAGAIN doesn't make sense for sleeping locks, and in some
587          * cases NLM_LCK_DENIED is returned for a permanent error.  So
588          * turn it into an ENOLCK.
589          */
590         if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
591                 status = -ENOLCK;
592         else
593                 status = nlm_stat_to_errno(resp->status);
594 out_unblock:
595         nlmclnt_finish_block(block);
596 out:
597         nlm_release_call(req);
598         return status;
599 out_unlock:
600         /* Fatal error: ensure that we remove the lock altogether */
601         dprintk("lockd: lock attempt ended in fatal error.\n"
602                 "       Attempting to unlock.\n");
603         nlmclnt_finish_block(block);
604         fl_type = fl->fl_type;
605         fl->fl_type = F_UNLCK;
606         down_read(&host->h_rwsem);
607         do_vfs_lock(fl);
608         up_read(&host->h_rwsem);
609         fl->fl_type = fl_type;
610         fl->fl_flags = fl_flags;
611         nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
612         return status;
613 }
614
615 /*
616  * RECLAIM: Try to reclaim a lock
617  */
618 int
619 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
620 {
621         struct nlm_rqst reqst, *req;
622         int             status;
623
624         req = &reqst;
625         memset(req, 0, sizeof(*req));
626         locks_init_lock(&req->a_args.lock.fl);
627         locks_init_lock(&req->a_res.lock.fl);
628         req->a_host  = host;
629         req->a_flags = 0;
630
631         /* Set up the argument struct */
632         nlmclnt_setlockargs(req, fl);
633         req->a_args.reclaim = 1;
634
635         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
636         if (status >= 0 && req->a_res.status == nlm_granted)
637                 return 0;
638
639         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
640                                 "(errno %d, status %d)\n", fl->fl_pid,
641                                 status, ntohl(req->a_res.status));
642
643         /*
644          * FIXME: This is a serious failure. We can
645          *
646          *  a.  Ignore the problem
647          *  b.  Send the owning process some signal (Linux doesn't have
648          *      SIGLOST, though...)
649          *  c.  Retry the operation
650          *
651          * Until someone comes up with a simple implementation
652          * for b or c, I'll choose option a.
653          */
654
655         return -ENOLCK;
656 }
657
658 /*
659  * UNLOCK: remove an existing lock
660  */
661 static int
662 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
663 {
664         struct nlm_host *host = req->a_host;
665         struct nlm_res  *resp = &req->a_res;
666         int status;
667         unsigned char fl_flags = fl->fl_flags;
668
669         /*
670          * Note: the server is supposed to either grant us the unlock
671          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
672          * case, we want to unlock.
673          */
674         fl->fl_flags |= FL_EXISTS;
675         down_read(&host->h_rwsem);
676         status = do_vfs_lock(fl);
677         up_read(&host->h_rwsem);
678         fl->fl_flags = fl_flags;
679         if (status == -ENOENT) {
680                 status = 0;
681                 goto out;
682         }
683
684         atomic_inc(&req->a_count);
685         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
686                         NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
687         if (status < 0)
688                 goto out;
689
690         if (resp->status == nlm_granted)
691                 goto out;
692
693         if (resp->status != nlm_lck_denied_nolocks)
694                 printk("lockd: unexpected unlock status: %d\n", resp->status);
695         /* What to do now? I'm out of my depth... */
696         status = -ENOLCK;
697 out:
698         nlm_release_call(req);
699         return status;
700 }
701
702 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
703 {
704         struct nlm_rqst *req = data;
705         u32 status = ntohl(req->a_res.status);
706
707         if (RPC_ASSASSINATED(task))
708                 goto die;
709
710         if (task->tk_status < 0) {
711                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
712                 goto retry_rebind;
713         }
714         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
715                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
716                 goto retry_unlock;
717         }
718         if (status != NLM_LCK_GRANTED)
719                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
720 die:
721         return;
722  retry_rebind:
723         lock_kernel();
724         nlm_rebind_host(req->a_host);
725         unlock_kernel();
726  retry_unlock:
727         rpc_restart_call(task);
728 }
729
730 static const struct rpc_call_ops nlmclnt_unlock_ops = {
731         .rpc_call_done = nlmclnt_unlock_callback,
732         .rpc_release = nlmclnt_rpc_release,
733 };
734
735 /*
736  * Cancel a blocked lock request.
737  * We always use an async RPC call for this in order not to hang a
738  * process that has been Ctrl-C'ed.
739  */
740 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
741 {
742         struct nlm_rqst *req;
743         int status;
744
745         dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
746                 "       Attempting to cancel lock.\n");
747
748         req = nlm_alloc_call(nlm_get_host(host));
749         if (!req)
750                 return -ENOMEM;
751         req->a_flags = RPC_TASK_ASYNC;
752
753         nlmclnt_setlockargs(req, fl);
754         req->a_args.block = block;
755
756         atomic_inc(&req->a_count);
757         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
758                         NLMPROC_CANCEL, &nlmclnt_cancel_ops);
759         if (status == 0 && req->a_res.status == nlm_lck_denied)
760                 status = -ENOLCK;
761         nlm_release_call(req);
762         return status;
763 }
764
765 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
766 {
767         struct nlm_rqst *req = data;
768         u32 status = ntohl(req->a_res.status);
769
770         if (RPC_ASSASSINATED(task))
771                 goto die;
772
773         if (task->tk_status < 0) {
774                 dprintk("lockd: CANCEL call error %d, retrying.\n",
775                                         task->tk_status);
776                 goto retry_cancel;
777         }
778
779         dprintk("lockd: cancel status %u (task %u)\n",
780                         status, task->tk_pid);
781
782         switch (status) {
783         case NLM_LCK_GRANTED:
784         case NLM_LCK_DENIED_GRACE_PERIOD:
785         case NLM_LCK_DENIED:
786                 /* Everything's good */
787                 break;
788         case NLM_LCK_DENIED_NOLOCKS:
789                 dprintk("lockd: CANCEL failed (server has no locks)\n");
790                 goto retry_cancel;
791         default:
792                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
793                         status);
794         }
795
796 die:
797         return;
798
799 retry_cancel:
800         /* Don't ever retry more than 3 times */
801         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
802                 goto die;
803         lock_kernel();
804         nlm_rebind_host(req->a_host);
805         unlock_kernel();
806         rpc_restart_call(task);
807         rpc_delay(task, 30 * HZ);
808 }
809
810 static const struct rpc_call_ops nlmclnt_cancel_ops = {
811         .rpc_call_done = nlmclnt_cancel_callback,
812         .rpc_release = nlmclnt_rpc_release,
813 };
814
815 /*
816  * Convert an NLM status code to a generic kernel errno
817  */
818 static int
819 nlm_stat_to_errno(__be32 status)
820 {
821         switch(ntohl(status)) {
822         case NLM_LCK_GRANTED:
823                 return 0;
824         case NLM_LCK_DENIED:
825                 return -EAGAIN;
826         case NLM_LCK_DENIED_NOLOCKS:
827         case NLM_LCK_DENIED_GRACE_PERIOD:
828                 return -ENOLCK;
829         case NLM_LCK_BLOCKED:
830                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
831                 return -ENOLCK;
832 #ifdef CONFIG_LOCKD_V4
833         case NLM_DEADLCK:
834                 return -EDEADLK;
835         case NLM_ROFS:
836                 return -EROFS;
837         case NLM_STALE_FH:
838                 return -ESTALE;
839         case NLM_FBIG:
840                 return -EOVERFLOW;
841         case NLM_FAILED:
842                 return -ENOLCK;
843 #endif
844         }
845         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
846         return -ENOLCK;
847 }