ocfs2: fix the end cluster offset of FIEMAP
[linux-3.10.git] / 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/slab.h>
11 #include <linux/types.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/nfs_fs.h>
15 #include <linux/utsname.h>
16 #include <linux/freezer.h>
17 #include <linux/sunrpc/clnt.h>
18 #include <linux/sunrpc/svc.h>
19 #include <linux/lockd/lockd.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         nlmclnt_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         char *nodename = req->a_host->h_rpcclnt->cl_nodename;
129
130         nlmclnt_next_cookie(&argp->cookie);
131         memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
132         lock->caller  = 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                                 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         WARN_ON_ONCE(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         call = nlm_alloc_call(host);
161         if (call == NULL)
162                 return -ENOMEM;
163
164         nlmclnt_locks_init_private(fl, host);
165         if (!fl->fl_u.nfs_fl.owner) {
166                 /* lockowner allocation has failed */
167                 nlmclnt_release_call(call);
168                 return -ENOMEM;
169         }
170         /* Set up the argument struct */
171         nlmclnt_setlockargs(call, fl);
172
173         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
174                 if (fl->fl_type != F_UNLCK) {
175                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
176                         status = nlmclnt_lock(call, fl);
177                 } else
178                         status = nlmclnt_unlock(call, fl);
179         } else if (IS_GETLK(cmd))
180                 status = nlmclnt_test(call, fl);
181         else
182                 status = -EINVAL;
183         fl->fl_ops->fl_release_private(fl);
184         fl->fl_ops = NULL;
185
186         dprintk("lockd: clnt proc returns %d\n", status);
187         return status;
188 }
189 EXPORT_SYMBOL_GPL(nlmclnt_proc);
190
191 /*
192  * Allocate an NLM RPC call struct
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 = nlm_get_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         return NULL;
213 }
214
215 void nlmclnt_release_call(struct nlm_rqst *call)
216 {
217         if (!atomic_dec_and_test(&call->a_count))
218                 return;
219         nlmclnt_release_host(call->a_host);
220         nlmclnt_release_lockargs(call);
221         kfree(call);
222 }
223
224 static void nlmclnt_rpc_release(void *data)
225 {
226         nlmclnt_release_call(data);
227 }
228
229 static int nlm_wait_on_grace(wait_queue_head_t *queue)
230 {
231         DEFINE_WAIT(wait);
232         int status = -EINTR;
233
234         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
235         if (!signalled ()) {
236                 schedule_timeout(NLMCLNT_GRACE_WAIT);
237                 try_to_freeze();
238                 if (!signalled ())
239                         status = 0;
240         }
241         finish_wait(queue, &wait);
242         return status;
243 }
244
245 /*
246  * Generic NLM call
247  */
248 static int
249 nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
250 {
251         struct nlm_host *host = req->a_host;
252         struct rpc_clnt *clnt;
253         struct nlm_args *argp = &req->a_args;
254         struct nlm_res  *resp = &req->a_res;
255         struct rpc_message msg = {
256                 .rpc_argp       = argp,
257                 .rpc_resp       = resp,
258                 .rpc_cred       = cred,
259         };
260         int             status;
261
262         dprintk("lockd: call procedure %d on %s\n",
263                         (int)proc, host->h_name);
264
265         do {
266                 if (host->h_reclaiming && !argp->reclaim)
267                         goto in_grace_period;
268
269                 /* If we have no RPC client yet, create one. */
270                 if ((clnt = nlm_bind_host(host)) == NULL)
271                         return -ENOLCK;
272                 msg.rpc_proc = &clnt->cl_procinfo[proc];
273
274                 /* Perform the RPC call. If an error occurs, try again */
275                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
276                         dprintk("lockd: rpc_call returned error %d\n", -status);
277                         switch (status) {
278                         case -EPROTONOSUPPORT:
279                                 status = -EINVAL;
280                                 break;
281                         case -ECONNREFUSED:
282                         case -ETIMEDOUT:
283                         case -ENOTCONN:
284                                 nlm_rebind_host(host);
285                                 status = -EAGAIN;
286                                 break;
287                         case -ERESTARTSYS:
288                                 return signalled () ? -EINTR : status;
289                         default:
290                                 break;
291                         }
292                         break;
293                 } else
294                 if (resp->status == nlm_lck_denied_grace_period) {
295                         dprintk("lockd: server in grace period\n");
296                         if (argp->reclaim) {
297                                 printk(KERN_WARNING
298                                      "lockd: spurious grace period reject?!\n");
299                                 return -ENOLCK;
300                         }
301                 } else {
302                         if (!argp->reclaim) {
303                                 /* We appear to be out of the grace period */
304                                 wake_up_all(&host->h_gracewait);
305                         }
306                         dprintk("lockd: server returns status %d\n",
307                                 ntohl(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_end;
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         nlmclnt_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         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
448         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
449         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
450         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
451         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
452 }
453
454 static void nlmclnt_locks_release_private(struct file_lock *fl)
455 {
456         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
457         list_del(&fl->fl_u.nfs_fl.list);
458         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
459         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
460 }
461
462 static const struct file_lock_operations nlmclnt_lock_ops = {
463         .fl_copy_lock = nlmclnt_locks_copy_lock,
464         .fl_release_private = nlmclnt_locks_release_private,
465 };
466
467 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
468 {
469         fl->fl_u.nfs_fl.state = 0;
470         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
471         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
472         fl->fl_ops = &nlmclnt_lock_ops;
473 }
474
475 static int do_vfs_lock(struct file_lock *fl)
476 {
477         int res = 0;
478         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
479                 case FL_POSIX:
480                         res = posix_lock_file_wait(fl->fl_file, fl);
481                         break;
482                 case FL_FLOCK:
483                         res = flock_lock_file_wait(fl->fl_file, fl);
484                         break;
485                 default:
486                         BUG();
487         }
488         return res;
489 }
490
491 /*
492  * LOCK: Try to create a lock
493  *
494  *                      Programmer Harassment Alert
495  *
496  * When given a blocking lock request in a sync RPC call, the HPUX lockd
497  * will faithfully return LCK_BLOCKED but never cares to notify us when
498  * the lock could be granted. This way, our local process could hang
499  * around forever waiting for the callback.
500  *
501  *  Solution A: Implement busy-waiting
502  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
503  *
504  * For now I am implementing solution A, because I hate the idea of
505  * re-implementing lockd for a third time in two months. The async
506  * calls shouldn't be too hard to do, however.
507  *
508  * This is one of the lovely things about standards in the NFS area:
509  * they're so soft and squishy you can't really blame HP for doing this.
510  */
511 static int
512 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
513 {
514         struct rpc_cred *cred = nfs_file_cred(fl->fl_file);
515         struct nlm_host *host = req->a_host;
516         struct nlm_res  *resp = &req->a_res;
517         struct nlm_wait *block = NULL;
518         unsigned char fl_flags = fl->fl_flags;
519         unsigned char fl_type;
520         int status = -ENOLCK;
521
522         if (nsm_monitor(host) < 0)
523                 goto out;
524         req->a_args.state = nsm_local_state;
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         nlmclnt_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                 struct nlm_rqst *req)
621 {
622         int             status;
623
624         memset(req, 0, sizeof(*req));
625         locks_init_lock(&req->a_args.lock.fl);
626         locks_init_lock(&req->a_res.lock.fl);
627         req->a_host  = host;
628
629         /* Set up the argument struct */
630         nlmclnt_setlockargs(req, fl);
631         req->a_args.reclaim = 1;
632
633         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
634         if (status >= 0 && req->a_res.status == nlm_granted)
635                 return 0;
636
637         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
638                                 "(errno %d, status %d)\n", fl->fl_pid,
639                                 status, ntohl(req->a_res.status));
640
641         /*
642          * FIXME: This is a serious failure. We can
643          *
644          *  a.  Ignore the problem
645          *  b.  Send the owning process some signal (Linux doesn't have
646          *      SIGLOST, though...)
647          *  c.  Retry the operation
648          *
649          * Until someone comes up with a simple implementation
650          * for b or c, I'll choose option a.
651          */
652
653         return -ENOLCK;
654 }
655
656 /*
657  * UNLOCK: remove an existing lock
658  */
659 static int
660 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
661 {
662         struct nlm_host *host = req->a_host;
663         struct nlm_res  *resp = &req->a_res;
664         int status;
665         unsigned char fl_flags = fl->fl_flags;
666
667         /*
668          * Note: the server is supposed to either grant us the unlock
669          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
670          * case, we want to unlock.
671          */
672         fl->fl_flags |= FL_EXISTS;
673         down_read(&host->h_rwsem);
674         status = do_vfs_lock(fl);
675         up_read(&host->h_rwsem);
676         fl->fl_flags = fl_flags;
677         if (status == -ENOENT) {
678                 status = 0;
679                 goto out;
680         }
681
682         atomic_inc(&req->a_count);
683         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
684                         NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
685         if (status < 0)
686                 goto out;
687
688         if (resp->status == nlm_granted)
689                 goto out;
690
691         if (resp->status != nlm_lck_denied_nolocks)
692                 printk("lockd: unexpected unlock status: %d\n",
693                         ntohl(resp->status));
694         /* What to do now? I'm out of my depth... */
695         status = -ENOLCK;
696 out:
697         nlmclnt_release_call(req);
698         return status;
699 }
700
701 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
702 {
703         struct nlm_rqst *req = data;
704         u32 status = ntohl(req->a_res.status);
705
706         if (RPC_ASSASSINATED(task))
707                 goto die;
708
709         if (task->tk_status < 0) {
710                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
711                 switch (task->tk_status) {
712                 case -EACCES:
713                 case -EIO:
714                         goto die;
715                 default:
716                         goto retry_rebind;
717                 }
718         }
719         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
720                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
721                 goto retry_unlock;
722         }
723         if (status != NLM_LCK_GRANTED)
724                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
725 die:
726         return;
727  retry_rebind:
728         nlm_rebind_host(req->a_host);
729  retry_unlock:
730         rpc_restart_call(task);
731 }
732
733 static const struct rpc_call_ops nlmclnt_unlock_ops = {
734         .rpc_call_done = nlmclnt_unlock_callback,
735         .rpc_release = nlmclnt_rpc_release,
736 };
737
738 /*
739  * Cancel a blocked lock request.
740  * We always use an async RPC call for this in order not to hang a
741  * process that has been Ctrl-C'ed.
742  */
743 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
744 {
745         struct nlm_rqst *req;
746         int status;
747
748         dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
749                 "       Attempting to cancel lock.\n");
750
751         req = nlm_alloc_call(host);
752         if (!req)
753                 return -ENOMEM;
754         req->a_flags = RPC_TASK_ASYNC;
755
756         nlmclnt_setlockargs(req, fl);
757         req->a_args.block = block;
758
759         atomic_inc(&req->a_count);
760         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
761                         NLMPROC_CANCEL, &nlmclnt_cancel_ops);
762         if (status == 0 && req->a_res.status == nlm_lck_denied)
763                 status = -ENOLCK;
764         nlmclnt_release_call(req);
765         return status;
766 }
767
768 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
769 {
770         struct nlm_rqst *req = data;
771         u32 status = ntohl(req->a_res.status);
772
773         if (RPC_ASSASSINATED(task))
774                 goto die;
775
776         if (task->tk_status < 0) {
777                 dprintk("lockd: CANCEL call error %d, retrying.\n",
778                                         task->tk_status);
779                 goto retry_cancel;
780         }
781
782         dprintk("lockd: cancel status %u (task %u)\n",
783                         status, task->tk_pid);
784
785         switch (status) {
786         case NLM_LCK_GRANTED:
787         case NLM_LCK_DENIED_GRACE_PERIOD:
788         case NLM_LCK_DENIED:
789                 /* Everything's good */
790                 break;
791         case NLM_LCK_DENIED_NOLOCKS:
792                 dprintk("lockd: CANCEL failed (server has no locks)\n");
793                 goto retry_cancel;
794         default:
795                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
796                         status);
797         }
798
799 die:
800         return;
801
802 retry_cancel:
803         /* Don't ever retry more than 3 times */
804         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
805                 goto die;
806         nlm_rebind_host(req->a_host);
807         rpc_restart_call(task);
808         rpc_delay(task, 30 * HZ);
809 }
810
811 static const struct rpc_call_ops nlmclnt_cancel_ops = {
812         .rpc_call_done = nlmclnt_cancel_callback,
813         .rpc_release = nlmclnt_rpc_release,
814 };
815
816 /*
817  * Convert an NLM status code to a generic kernel errno
818  */
819 static int
820 nlm_stat_to_errno(__be32 status)
821 {
822         switch(ntohl(status)) {
823         case NLM_LCK_GRANTED:
824                 return 0;
825         case NLM_LCK_DENIED:
826                 return -EAGAIN;
827         case NLM_LCK_DENIED_NOLOCKS:
828         case NLM_LCK_DENIED_GRACE_PERIOD:
829                 return -ENOLCK;
830         case NLM_LCK_BLOCKED:
831                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
832                 return -ENOLCK;
833 #ifdef CONFIG_LOCKD_V4
834         case NLM_DEADLCK:
835                 return -EDEADLK;
836         case NLM_ROFS:
837                 return -EROFS;
838         case NLM_STALE_FH:
839                 return -ESTALE;
840         case NLM_FBIG:
841                 return -EOVERFLOW;
842         case NLM_FAILED:
843                 return -ENOLCK;
844 #endif
845         }
846         printk(KERN_NOTICE "lockd: unexpected server status %d\n",
847                  ntohl(status));
848         return -ENOLCK;
849 }