lockd: Move nlmdbg_cookie2a() to svclock.c
[linux-2.6.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         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         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
131         lock->caller  = utsname()->nodename;
132         lock->oh.data = req->a_owner;
133         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
134                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
135                                 utsname()->nodename);
136         lock->svid = fl->fl_u.nfs_fl.owner->pid;
137         lock->fl.fl_start = fl->fl_start;
138         lock->fl.fl_end = fl->fl_end;
139         lock->fl.fl_type = fl->fl_type;
140 }
141
142 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
143 {
144         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
145 }
146
147 /**
148  * nlmclnt_proc - Perform a single client-side lock request
149  * @host: address of a valid nlm_host context representing the NLM server
150  * @cmd: fcntl-style file lock operation to perform
151  * @fl: address of arguments for the lock operation
152  *
153  */
154 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
155 {
156         struct nlm_rqst         *call;
157         int                     status;
158
159         nlm_get_host(host);
160         call = nlm_alloc_call(host);
161         if (call == NULL)
162                 return -ENOMEM;
163
164         nlmclnt_locks_init_private(fl, host);
165         /* Set up the argument struct */
166         nlmclnt_setlockargs(call, fl);
167
168         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
169                 if (fl->fl_type != F_UNLCK) {
170                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
171                         status = nlmclnt_lock(call, fl);
172                 } else
173                         status = nlmclnt_unlock(call, fl);
174         } else if (IS_GETLK(cmd))
175                 status = nlmclnt_test(call, fl);
176         else
177                 status = -EINVAL;
178         fl->fl_ops->fl_release_private(fl);
179         fl->fl_ops = NULL;
180
181         dprintk("lockd: clnt proc returns %d\n", status);
182         return status;
183 }
184 EXPORT_SYMBOL_GPL(nlmclnt_proc);
185
186 /*
187  * Allocate an NLM RPC call struct
188  *
189  * Note: the caller must hold a reference to host. In case of failure,
190  * this reference will be released.
191  */
192 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
193 {
194         struct nlm_rqst *call;
195
196         for(;;) {
197                 call = kzalloc(sizeof(*call), GFP_KERNEL);
198                 if (call != NULL) {
199                         atomic_set(&call->a_count, 1);
200                         locks_init_lock(&call->a_args.lock.fl);
201                         locks_init_lock(&call->a_res.lock.fl);
202                         call->a_host = host;
203                         return call;
204                 }
205                 if (signalled())
206                         break;
207                 printk("nlm_alloc_call: failed, waiting for memory\n");
208                 schedule_timeout_interruptible(5*HZ);
209         }
210         nlm_release_host(host);
211         return NULL;
212 }
213
214 void nlm_release_call(struct nlm_rqst *call)
215 {
216         if (!atomic_dec_and_test(&call->a_count))
217                 return;
218         nlm_release_host(call->a_host);
219         nlmclnt_release_lockargs(call);
220         kfree(call);
221 }
222
223 static void nlmclnt_rpc_release(void *data)
224 {
225         nlm_release_call(data);
226 }
227
228 static int nlm_wait_on_grace(wait_queue_head_t *queue)
229 {
230         DEFINE_WAIT(wait);
231         int status = -EINTR;
232
233         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
234         if (!signalled ()) {
235                 schedule_timeout(NLMCLNT_GRACE_WAIT);
236                 try_to_freeze();
237                 if (!signalled ())
238                         status = 0;
239         }
240         finish_wait(queue, &wait);
241         return status;
242 }
243
244 /*
245  * Generic NLM call
246  */
247 static int
248 nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
249 {
250         struct nlm_host *host = req->a_host;
251         struct rpc_clnt *clnt;
252         struct nlm_args *argp = &req->a_args;
253         struct nlm_res  *resp = &req->a_res;
254         struct rpc_message msg = {
255                 .rpc_argp       = argp,
256                 .rpc_resp       = resp,
257                 .rpc_cred       = cred,
258         };
259         int             status;
260
261         dprintk("lockd: call procedure %d on %s\n",
262                         (int)proc, host->h_name);
263
264         do {
265                 if (host->h_reclaiming && !argp->reclaim)
266                         goto in_grace_period;
267
268                 /* If we have no RPC client yet, create one. */
269                 if ((clnt = nlm_bind_host(host)) == NULL)
270                         return -ENOLCK;
271                 msg.rpc_proc = &clnt->cl_procinfo[proc];
272
273                 /* Perform the RPC call. If an error occurs, try again */
274                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
275                         dprintk("lockd: rpc_call returned error %d\n", -status);
276                         switch (status) {
277                         case -EPROTONOSUPPORT:
278                                 status = -EINVAL;
279                                 break;
280                         case -ECONNREFUSED:
281                         case -ETIMEDOUT:
282                         case -ENOTCONN:
283                                 nlm_rebind_host(host);
284                                 status = -EAGAIN;
285                                 break;
286                         case -ERESTARTSYS:
287                                 return signalled () ? -EINTR : status;
288                         default:
289                                 break;
290                         }
291                         break;
292                 } else
293                 if (resp->status == nlm_lck_denied_grace_period) {
294                         dprintk("lockd: server in grace period\n");
295                         if (argp->reclaim) {
296                                 printk(KERN_WARNING
297                                      "lockd: spurious grace period reject?!\n");
298                                 return -ENOLCK;
299                         }
300                 } else {
301                         if (!argp->reclaim) {
302                                 /* We appear to be out of the grace period */
303                                 wake_up_all(&host->h_gracewait);
304                         }
305                         dprintk("lockd: server returns status %d\n", resp->status);
306                         return 0;       /* Okay, call complete */
307                 }
308
309 in_grace_period:
310                 /*
311                  * The server has rebooted and appears to be in the grace
312                  * period during which locks are only allowed to be
313                  * reclaimed.
314                  * We can only back off and try again later.
315                  */
316                 status = nlm_wait_on_grace(&host->h_gracewait);
317         } while (status == 0);
318
319         return status;
320 }
321
322 /*
323  * Generic NLM call, async version.
324  */
325 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
326 {
327         struct nlm_host *host = req->a_host;
328         struct rpc_clnt *clnt;
329         struct rpc_task_setup task_setup_data = {
330                 .rpc_message = msg,
331                 .callback_ops = tk_ops,
332                 .callback_data = req,
333                 .flags = RPC_TASK_ASYNC,
334         };
335
336         dprintk("lockd: call procedure %d on %s (async)\n",
337                         (int)proc, host->h_name);
338
339         /* If we have no RPC client yet, create one. */
340         clnt = nlm_bind_host(host);
341         if (clnt == NULL)
342                 goto out_err;
343         msg->rpc_proc = &clnt->cl_procinfo[proc];
344         task_setup_data.rpc_client = clnt;
345
346         /* bootstrap and kick off the async RPC call */
347         return rpc_run_task(&task_setup_data);
348 out_err:
349         tk_ops->rpc_release(req);
350         return ERR_PTR(-ENOLCK);
351 }
352
353 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
354 {
355         struct rpc_task *task;
356
357         task = __nlm_async_call(req, proc, msg, tk_ops);
358         if (IS_ERR(task))
359                 return PTR_ERR(task);
360         rpc_put_task(task);
361         return 0;
362 }
363
364 /*
365  * NLM asynchronous call.
366  */
367 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
368 {
369         struct rpc_message msg = {
370                 .rpc_argp       = &req->a_args,
371                 .rpc_resp       = &req->a_res,
372         };
373         return nlm_do_async_call(req, proc, &msg, tk_ops);
374 }
375
376 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
377 {
378         struct rpc_message msg = {
379                 .rpc_argp       = &req->a_res,
380         };
381         return nlm_do_async_call(req, proc, &msg, tk_ops);
382 }
383
384 /*
385  * NLM client asynchronous call.
386  *
387  * Note that although the calls are asynchronous, and are therefore
388  *      guaranteed to complete, we still always attempt to wait for
389  *      completion in order to be able to correctly track the lock
390  *      state.
391  */
392 static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
393 {
394         struct rpc_message msg = {
395                 .rpc_argp       = &req->a_args,
396                 .rpc_resp       = &req->a_res,
397                 .rpc_cred       = cred,
398         };
399         struct rpc_task *task;
400         int err;
401
402         task = __nlm_async_call(req, proc, &msg, tk_ops);
403         if (IS_ERR(task))
404                 return PTR_ERR(task);
405         err = rpc_wait_for_completion_task(task);
406         rpc_put_task(task);
407         return err;
408 }
409
410 /*
411  * TEST for the presence of a conflicting lock
412  */
413 static int
414 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
415 {
416         int     status;
417
418         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
419         if (status < 0)
420                 goto out;
421
422         switch (req->a_res.status) {
423                 case nlm_granted:
424                         fl->fl_type = F_UNLCK;
425                         break;
426                 case nlm_lck_denied:
427                         /*
428                          * Report the conflicting lock back to the application.
429                          */
430                         fl->fl_start = req->a_res.lock.fl.fl_start;
431                         fl->fl_end = req->a_res.lock.fl.fl_end;
432                         fl->fl_type = req->a_res.lock.fl.fl_type;
433                         fl->fl_pid = 0;
434                         break;
435                 default:
436                         status = nlm_stat_to_errno(req->a_res.status);
437         }
438 out:
439         nlm_release_call(req);
440         return status;
441 }
442
443 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
444 {
445         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
446         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
447         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
448         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
449         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
450 }
451
452 static void nlmclnt_locks_release_private(struct file_lock *fl)
453 {
454         spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
455         list_del(&fl->fl_u.nfs_fl.list);
456         spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
457         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
458 }
459
460 static const 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                 goto out;
523         req->a_args.state = nsm_local_state;
524
525         fl->fl_flags |= FL_ACCESS;
526         status = do_vfs_lock(fl);
527         fl->fl_flags = fl_flags;
528         if (status < 0)
529                 goto out;
530
531         block = nlmclnt_prepare_block(host, fl);
532 again:
533         /*
534          * Initialise resp->status to a valid non-zero value,
535          * since 0 == nlm_lck_granted
536          */
537         resp->status = nlm_lck_blocked;
538         for(;;) {
539                 /* Reboot protection */
540                 fl->fl_u.nfs_fl.state = host->h_state;
541                 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
542                 if (status < 0)
543                         break;
544                 /* Did a reclaimer thread notify us of a server reboot? */
545                 if (resp->status ==  nlm_lck_denied_grace_period)
546                         continue;
547                 if (resp->status != nlm_lck_blocked)
548                         break;
549                 /* Wait on an NLM blocking lock */
550                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
551                 if (status < 0)
552                         break;
553                 if (resp->status != nlm_lck_blocked)
554                         break;
555         }
556
557         /* if we were interrupted while blocking, then cancel the lock request
558          * and exit
559          */
560         if (resp->status == nlm_lck_blocked) {
561                 if (!req->a_args.block)
562                         goto out_unlock;
563                 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
564                         goto out_unblock;
565         }
566
567         if (resp->status == nlm_granted) {
568                 down_read(&host->h_rwsem);
569                 /* Check whether or not the server has rebooted */
570                 if (fl->fl_u.nfs_fl.state != host->h_state) {
571                         up_read(&host->h_rwsem);
572                         goto again;
573                 }
574                 /* Ensure the resulting lock will get added to granted list */
575                 fl->fl_flags |= FL_SLEEP;
576                 if (do_vfs_lock(fl) < 0)
577                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
578                 up_read(&host->h_rwsem);
579                 fl->fl_flags = fl_flags;
580                 status = 0;
581         }
582         if (status < 0)
583                 goto out_unlock;
584         /*
585          * EAGAIN doesn't make sense for sleeping locks, and in some
586          * cases NLM_LCK_DENIED is returned for a permanent error.  So
587          * turn it into an ENOLCK.
588          */
589         if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
590                 status = -ENOLCK;
591         else
592                 status = nlm_stat_to_errno(resp->status);
593 out_unblock:
594         nlmclnt_finish_block(block);
595 out:
596         nlm_release_call(req);
597         return status;
598 out_unlock:
599         /* Fatal error: ensure that we remove the lock altogether */
600         dprintk("lockd: lock attempt ended in fatal error.\n"
601                 "       Attempting to unlock.\n");
602         nlmclnt_finish_block(block);
603         fl_type = fl->fl_type;
604         fl->fl_type = F_UNLCK;
605         down_read(&host->h_rwsem);
606         do_vfs_lock(fl);
607         up_read(&host->h_rwsem);
608         fl->fl_type = fl_type;
609         fl->fl_flags = fl_flags;
610         nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
611         return status;
612 }
613
614 /*
615  * RECLAIM: Try to reclaim a lock
616  */
617 int
618 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
619 {
620         struct nlm_rqst reqst, *req;
621         int             status;
622
623         req = &reqst;
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         req->a_flags = 0;
629
630         /* Set up the argument struct */
631         nlmclnt_setlockargs(req, fl);
632         req->a_args.reclaim = 1;
633
634         status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
635         if (status >= 0 && req->a_res.status == nlm_granted)
636                 return 0;
637
638         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
639                                 "(errno %d, status %d)\n", fl->fl_pid,
640                                 status, ntohl(req->a_res.status));
641
642         /*
643          * FIXME: This is a serious failure. We can
644          *
645          *  a.  Ignore the problem
646          *  b.  Send the owning process some signal (Linux doesn't have
647          *      SIGLOST, though...)
648          *  c.  Retry the operation
649          *
650          * Until someone comes up with a simple implementation
651          * for b or c, I'll choose option a.
652          */
653
654         return -ENOLCK;
655 }
656
657 /*
658  * UNLOCK: remove an existing lock
659  */
660 static int
661 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
662 {
663         struct nlm_host *host = req->a_host;
664         struct nlm_res  *resp = &req->a_res;
665         int status;
666         unsigned char fl_flags = fl->fl_flags;
667
668         /*
669          * Note: the server is supposed to either grant us the unlock
670          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
671          * case, we want to unlock.
672          */
673         fl->fl_flags |= FL_EXISTS;
674         down_read(&host->h_rwsem);
675         status = do_vfs_lock(fl);
676         up_read(&host->h_rwsem);
677         fl->fl_flags = fl_flags;
678         if (status == -ENOENT) {
679                 status = 0;
680                 goto out;
681         }
682
683         atomic_inc(&req->a_count);
684         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
685                         NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
686         if (status < 0)
687                 goto out;
688
689         if (resp->status == nlm_granted)
690                 goto out;
691
692         if (resp->status != nlm_lck_denied_nolocks)
693                 printk("lockd: unexpected unlock status: %d\n", resp->status);
694         /* What to do now? I'm out of my depth... */
695         status = -ENOLCK;
696 out:
697         nlm_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                 goto retry_rebind;
712         }
713         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
714                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
715                 goto retry_unlock;
716         }
717         if (status != NLM_LCK_GRANTED)
718                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
719 die:
720         return;
721  retry_rebind:
722         nlm_rebind_host(req->a_host);
723  retry_unlock:
724         rpc_restart_call(task);
725 }
726
727 static const struct rpc_call_ops nlmclnt_unlock_ops = {
728         .rpc_call_done = nlmclnt_unlock_callback,
729         .rpc_release = nlmclnt_rpc_release,
730 };
731
732 /*
733  * Cancel a blocked lock request.
734  * We always use an async RPC call for this in order not to hang a
735  * process that has been Ctrl-C'ed.
736  */
737 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
738 {
739         struct nlm_rqst *req;
740         int status;
741
742         dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
743                 "       Attempting to cancel lock.\n");
744
745         req = nlm_alloc_call(nlm_get_host(host));
746         if (!req)
747                 return -ENOMEM;
748         req->a_flags = RPC_TASK_ASYNC;
749
750         nlmclnt_setlockargs(req, fl);
751         req->a_args.block = block;
752
753         atomic_inc(&req->a_count);
754         status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
755                         NLMPROC_CANCEL, &nlmclnt_cancel_ops);
756         if (status == 0 && req->a_res.status == nlm_lck_denied)
757                 status = -ENOLCK;
758         nlm_release_call(req);
759         return status;
760 }
761
762 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
763 {
764         struct nlm_rqst *req = data;
765         u32 status = ntohl(req->a_res.status);
766
767         if (RPC_ASSASSINATED(task))
768                 goto die;
769
770         if (task->tk_status < 0) {
771                 dprintk("lockd: CANCEL call error %d, retrying.\n",
772                                         task->tk_status);
773                 goto retry_cancel;
774         }
775
776         dprintk("lockd: cancel status %u (task %u)\n",
777                         status, task->tk_pid);
778
779         switch (status) {
780         case NLM_LCK_GRANTED:
781         case NLM_LCK_DENIED_GRACE_PERIOD:
782         case NLM_LCK_DENIED:
783                 /* Everything's good */
784                 break;
785         case NLM_LCK_DENIED_NOLOCKS:
786                 dprintk("lockd: CANCEL failed (server has no locks)\n");
787                 goto retry_cancel;
788         default:
789                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
790                         status);
791         }
792
793 die:
794         return;
795
796 retry_cancel:
797         /* Don't ever retry more than 3 times */
798         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
799                 goto die;
800         nlm_rebind_host(req->a_host);
801         rpc_restart_call(task);
802         rpc_delay(task, 30 * HZ);
803 }
804
805 static const struct rpc_call_ops nlmclnt_cancel_ops = {
806         .rpc_call_done = nlmclnt_cancel_callback,
807         .rpc_release = nlmclnt_rpc_release,
808 };
809
810 /*
811  * Convert an NLM status code to a generic kernel errno
812  */
813 static int
814 nlm_stat_to_errno(__be32 status)
815 {
816         switch(ntohl(status)) {
817         case NLM_LCK_GRANTED:
818                 return 0;
819         case NLM_LCK_DENIED:
820                 return -EAGAIN;
821         case NLM_LCK_DENIED_NOLOCKS:
822         case NLM_LCK_DENIED_GRACE_PERIOD:
823                 return -ENOLCK;
824         case NLM_LCK_BLOCKED:
825                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
826                 return -ENOLCK;
827 #ifdef CONFIG_LOCKD_V4
828         case NLM_DEADLCK:
829                 return -EDEADLK;
830         case NLM_ROFS:
831                 return -EROFS;
832         case NLM_STALE_FH:
833                 return -ESTALE;
834         case NLM_FBIG:
835                 return -EOVERFLOW;
836         case NLM_FAILED:
837                 return -ENOLCK;
838 #endif
839         }
840         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
841         return -ENOLCK;
842 }