Merge branch 'master' of /home/trondmy/kernel/linux-2.6/ into merge_linus
[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/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/smp_lock.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 #include <linux/lockd/sm_inter.h>
21
22 #define NLMDBG_FACILITY         NLMDBG_CLIENT
23 #define NLMCLNT_GRACE_WAIT      (5*HZ)
24 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
25 #define NLMCLNT_MAX_RETRIES     3
26
27 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
28 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
29 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
30 static int      nlm_stat_to_errno(u32 stat);
31 static void     nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
32 static int      nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
33
34 static const struct rpc_call_ops nlmclnt_unlock_ops;
35 static const struct rpc_call_ops nlmclnt_cancel_ops;
36
37 /*
38  * Cookie counter for NLM requests
39  */
40 static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
41
42 void nlmclnt_next_cookie(struct nlm_cookie *c)
43 {
44         u32     cookie = atomic_inc_return(&nlm_cookie);
45
46         memcpy(c->data, &cookie, 4);
47         c->len=4;
48 }
49
50 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
51 {
52         atomic_inc(&lockowner->count);
53         return lockowner;
54 }
55
56 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
57 {
58         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
59                 return;
60         list_del(&lockowner->list);
61         spin_unlock(&lockowner->host->h_lock);
62         nlm_release_host(lockowner->host);
63         kfree(lockowner);
64 }
65
66 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
67 {
68         struct nlm_lockowner *lockowner;
69         list_for_each_entry(lockowner, &host->h_lockowners, list) {
70                 if (lockowner->pid == pid)
71                         return -EBUSY;
72         }
73         return 0;
74 }
75
76 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
77 {
78         uint32_t res;
79         do {
80                 res = host->h_pidcount++;
81         } while (nlm_pidbusy(host, res) < 0);
82         return res;
83 }
84
85 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
86 {
87         struct nlm_lockowner *lockowner;
88         list_for_each_entry(lockowner, &host->h_lockowners, list) {
89                 if (lockowner->owner != owner)
90                         continue;
91                 return nlm_get_lockowner(lockowner);
92         }
93         return NULL;
94 }
95
96 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
97 {
98         struct nlm_lockowner *res, *new = NULL;
99
100         spin_lock(&host->h_lock);
101         res = __nlm_find_lockowner(host, owner);
102         if (res == NULL) {
103                 spin_unlock(&host->h_lock);
104                 new = kmalloc(sizeof(*new), GFP_KERNEL);
105                 spin_lock(&host->h_lock);
106                 res = __nlm_find_lockowner(host, owner);
107                 if (res == NULL && new != NULL) {
108                         res = new;
109                         atomic_set(&new->count, 1);
110                         new->owner = owner;
111                         new->pid = __nlm_alloc_pid(host);
112                         new->host = nlm_get_host(host);
113                         list_add(&new->list, &host->h_lockowners);
114                         new = NULL;
115                 }
116         }
117         spin_unlock(&host->h_lock);
118         kfree(new);
119         return res;
120 }
121
122 /*
123  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
124  */
125 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
126 {
127         struct nlm_args *argp = &req->a_args;
128         struct nlm_lock *lock = &argp->lock;
129
130         nlmclnt_next_cookie(&argp->cookie);
131         argp->state   = nsm_local_state;
132         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
133         lock->caller  = utsname()->nodename;
134         lock->oh.data = req->a_owner;
135         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
136                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
137                                 utsname()->nodename);
138         lock->svid = fl->fl_u.nfs_fl.owner->pid;
139         lock->fl.fl_start = fl->fl_start;
140         lock->fl.fl_end = fl->fl_end;
141         lock->fl.fl_type = fl->fl_type;
142 }
143
144 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
145 {
146         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
147 }
148
149 /*
150  * This is the main entry point for the NLM client.
151  */
152 int
153 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
154 {
155         struct rpc_clnt         *client = NFS_CLIENT(inode);
156         struct sockaddr_in      addr;
157         struct nfs_server       *nfssrv = NFS_SERVER(inode);
158         struct nlm_host         *host;
159         struct nlm_rqst         *call;
160         sigset_t                oldset;
161         unsigned long           flags;
162         int                     status, vers;
163
164         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
165         if (NFS_PROTO(inode)->version > 3) {
166                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
167                 return -ENOLCK;
168         }
169
170         rpc_peeraddr(client, (struct sockaddr *) &addr, sizeof(addr));
171         host = nlmclnt_lookup_host(&addr, client->cl_xprt->prot, vers,
172                                    nfssrv->nfs_client->cl_hostname,
173                                    strlen(nfssrv->nfs_client->cl_hostname));
174         if (host == NULL)
175                 return -ENOLCK;
176
177         call = nlm_alloc_call(host);
178         if (call == NULL)
179                 return -ENOMEM;
180
181         nlmclnt_locks_init_private(fl, host);
182         /* Set up the argument struct */
183         nlmclnt_setlockargs(call, fl);
184
185         /* Keep the old signal mask */
186         spin_lock_irqsave(&current->sighand->siglock, flags);
187         oldset = current->blocked;
188
189         /* If we're cleaning up locks because the process is exiting,
190          * perform the RPC call asynchronously. */
191         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
192             && fl->fl_type == F_UNLCK
193             && (current->flags & PF_EXITING)) {
194                 sigfillset(&current->blocked);  /* Mask all signals */
195                 recalc_sigpending();
196
197                 call->a_flags = RPC_TASK_ASYNC;
198         }
199         spin_unlock_irqrestore(&current->sighand->siglock, flags);
200
201         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
202                 if (fl->fl_type != F_UNLCK) {
203                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
204                         status = nlmclnt_lock(call, fl);
205                 } else
206                         status = nlmclnt_unlock(call, fl);
207         } else if (IS_GETLK(cmd))
208                 status = nlmclnt_test(call, fl);
209         else
210                 status = -EINVAL;
211
212         fl->fl_ops->fl_release_private(fl);
213         fl->fl_ops = NULL;
214
215         spin_lock_irqsave(&current->sighand->siglock, flags);
216         current->blocked = oldset;
217         recalc_sigpending();
218         spin_unlock_irqrestore(&current->sighand->siglock, flags);
219
220         dprintk("lockd: clnt proc returns %d\n", status);
221         return status;
222 }
223 EXPORT_SYMBOL(nlmclnt_proc);
224
225 /*
226  * Allocate an NLM RPC call struct
227  *
228  * Note: the caller must hold a reference to host. In case of failure,
229  * this reference will be released.
230  */
231 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
232 {
233         struct nlm_rqst *call;
234
235         for(;;) {
236                 call = kzalloc(sizeof(*call), GFP_KERNEL);
237                 if (call != NULL) {
238                         locks_init_lock(&call->a_args.lock.fl);
239                         locks_init_lock(&call->a_res.lock.fl);
240                         call->a_host = host;
241                         return call;
242                 }
243                 if (signalled())
244                         break;
245                 printk("nlm_alloc_call: failed, waiting for memory\n");
246                 schedule_timeout_interruptible(5*HZ);
247         }
248         nlm_release_host(host);
249         return NULL;
250 }
251
252 void nlm_release_call(struct nlm_rqst *call)
253 {
254         nlm_release_host(call->a_host);
255         nlmclnt_release_lockargs(call);
256         kfree(call);
257 }
258
259 static void nlmclnt_rpc_release(void *data)
260 {
261         return nlm_release_call(data);
262 }
263
264 static int nlm_wait_on_grace(wait_queue_head_t *queue)
265 {
266         DEFINE_WAIT(wait);
267         int status = -EINTR;
268
269         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
270         if (!signalled ()) {
271                 schedule_timeout(NLMCLNT_GRACE_WAIT);
272                 try_to_freeze();
273                 if (!signalled ())
274                         status = 0;
275         }
276         finish_wait(queue, &wait);
277         return status;
278 }
279
280 /*
281  * Generic NLM call
282  */
283 static int
284 nlmclnt_call(struct nlm_rqst *req, u32 proc)
285 {
286         struct nlm_host *host = req->a_host;
287         struct rpc_clnt *clnt;
288         struct nlm_args *argp = &req->a_args;
289         struct nlm_res  *resp = &req->a_res;
290         struct rpc_message msg = {
291                 .rpc_argp       = argp,
292                 .rpc_resp       = resp,
293         };
294         int             status;
295
296         dprintk("lockd: call procedure %d on %s\n",
297                         (int)proc, host->h_name);
298
299         do {
300                 if (host->h_reclaiming && !argp->reclaim)
301                         goto in_grace_period;
302
303                 /* If we have no RPC client yet, create one. */
304                 if ((clnt = nlm_bind_host(host)) == NULL)
305                         return -ENOLCK;
306                 msg.rpc_proc = &clnt->cl_procinfo[proc];
307
308                 /* Perform the RPC call. If an error occurs, try again */
309                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
310                         dprintk("lockd: rpc_call returned error %d\n", -status);
311                         switch (status) {
312                         case -EPROTONOSUPPORT:
313                                 status = -EINVAL;
314                                 break;
315                         case -ECONNREFUSED:
316                         case -ETIMEDOUT:
317                         case -ENOTCONN:
318                                 nlm_rebind_host(host);
319                                 status = -EAGAIN;
320                                 break;
321                         case -ERESTARTSYS:
322                                 return signalled () ? -EINTR : status;
323                         default:
324                                 break;
325                         }
326                         break;
327                 } else
328                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
329                         dprintk("lockd: server in grace period\n");
330                         if (argp->reclaim) {
331                                 printk(KERN_WARNING
332                                      "lockd: spurious grace period reject?!\n");
333                                 return -ENOLCK;
334                         }
335                 } else {
336                         if (!argp->reclaim) {
337                                 /* We appear to be out of the grace period */
338                                 wake_up_all(&host->h_gracewait);
339                         }
340                         dprintk("lockd: server returns status %d\n", resp->status);
341                         return 0;       /* Okay, call complete */
342                 }
343
344 in_grace_period:
345                 /*
346                  * The server has rebooted and appears to be in the grace
347                  * period during which locks are only allowed to be
348                  * reclaimed.
349                  * We can only back off and try again later.
350                  */
351                 status = nlm_wait_on_grace(&host->h_gracewait);
352         } while (status == 0);
353
354         return status;
355 }
356
357 /*
358  * Generic NLM call, async version.
359  */
360 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
361 {
362         struct nlm_host *host = req->a_host;
363         struct rpc_clnt *clnt;
364         int status = -ENOLCK;
365
366         dprintk("lockd: call procedure %d on %s (async)\n",
367                         (int)proc, host->h_name);
368
369         /* If we have no RPC client yet, create one. */
370         clnt = nlm_bind_host(host);
371         if (clnt == NULL)
372                 goto out_err;
373         msg->rpc_proc = &clnt->cl_procinfo[proc];
374
375         /* bootstrap and kick off the async RPC call */
376         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
377         if (status == 0)
378                 return 0;
379 out_err:
380         nlm_release_call(req);
381         return status;
382 }
383
384 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
385 {
386         struct rpc_message msg = {
387                 .rpc_argp       = &req->a_args,
388                 .rpc_resp       = &req->a_res,
389         };
390         return __nlm_async_call(req, proc, &msg, tk_ops);
391 }
392
393 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
394 {
395         struct rpc_message msg = {
396                 .rpc_argp       = &req->a_res,
397         };
398         return __nlm_async_call(req, proc, &msg, tk_ops);
399 }
400
401 /*
402  * TEST for the presence of a conflicting lock
403  */
404 static int
405 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
406 {
407         int     status;
408
409         status = nlmclnt_call(req, NLMPROC_TEST);
410         if (status < 0)
411                 goto out;
412
413         switch (req->a_res.status) {
414                 case NLM_LCK_GRANTED:
415                         fl->fl_type = F_UNLCK;
416                         break;
417                 case NLM_LCK_DENIED:
418                         /*
419                          * Report the conflicting lock back to the application.
420                          */
421                         fl->fl_start = req->a_res.lock.fl.fl_start;
422                         fl->fl_end = req->a_res.lock.fl.fl_start;
423                         fl->fl_type = req->a_res.lock.fl.fl_type;
424                         fl->fl_pid = 0;
425                         break;
426                 default:
427                         status = nlm_stat_to_errno(req->a_res.status);
428         }
429 out:
430         nlm_release_call(req);
431         return status;
432 }
433
434 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
435 {
436         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
437         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
438         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
439 }
440
441 static void nlmclnt_locks_release_private(struct file_lock *fl)
442 {
443         list_del(&fl->fl_u.nfs_fl.list);
444         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
445 }
446
447 static struct file_lock_operations nlmclnt_lock_ops = {
448         .fl_copy_lock = nlmclnt_locks_copy_lock,
449         .fl_release_private = nlmclnt_locks_release_private,
450 };
451
452 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
453 {
454         BUG_ON(fl->fl_ops != NULL);
455         fl->fl_u.nfs_fl.state = 0;
456         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
457         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
458         fl->fl_ops = &nlmclnt_lock_ops;
459 }
460
461 static int do_vfs_lock(struct file_lock *fl)
462 {
463         int res = 0;
464         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
465                 case FL_POSIX:
466                         res = posix_lock_file_wait(fl->fl_file, fl);
467                         break;
468                 case FL_FLOCK:
469                         res = flock_lock_file_wait(fl->fl_file, fl);
470                         break;
471                 default:
472                         BUG();
473         }
474         return res;
475 }
476
477 /*
478  * LOCK: Try to create a lock
479  *
480  *                      Programmer Harassment Alert
481  *
482  * When given a blocking lock request in a sync RPC call, the HPUX lockd
483  * will faithfully return LCK_BLOCKED but never cares to notify us when
484  * the lock could be granted. This way, our local process could hang
485  * around forever waiting for the callback.
486  *
487  *  Solution A: Implement busy-waiting
488  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
489  *
490  * For now I am implementing solution A, because I hate the idea of
491  * re-implementing lockd for a third time in two months. The async
492  * calls shouldn't be too hard to do, however.
493  *
494  * This is one of the lovely things about standards in the NFS area:
495  * they're so soft and squishy you can't really blame HP for doing this.
496  */
497 static int
498 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
499 {
500         struct nlm_host *host = req->a_host;
501         struct nlm_res  *resp = &req->a_res;
502         struct nlm_wait *block = NULL;
503         unsigned char fl_flags = fl->fl_flags;
504         int status = -ENOLCK;
505
506         if (nsm_monitor(host) < 0) {
507                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
508                                         host->h_name);
509                 goto out;
510         }
511         fl->fl_flags |= FL_ACCESS;
512         status = do_vfs_lock(fl);
513         if (status < 0)
514                 goto out;
515
516         block = nlmclnt_prepare_block(host, fl);
517 again:
518         for(;;) {
519                 /* Reboot protection */
520                 fl->fl_u.nfs_fl.state = host->h_state;
521                 status = nlmclnt_call(req, NLMPROC_LOCK);
522                 if (status < 0)
523                         goto out_unblock;
524                 if (!req->a_args.block)
525                         break;
526                 /* Did a reclaimer thread notify us of a server reboot? */
527                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
528                         continue;
529                 if (resp->status != NLM_LCK_BLOCKED)
530                         break;
531                 /* Wait on an NLM blocking lock */
532                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
533                 /* if we were interrupted. Send a CANCEL request to the server
534                  * and exit
535                  */
536                 if (status < 0)
537                         goto out_unblock;
538                 if (resp->status != NLM_LCK_BLOCKED)
539                         break;
540         }
541
542         if (resp->status == NLM_LCK_GRANTED) {
543                 down_read(&host->h_rwsem);
544                 /* Check whether or not the server has rebooted */
545                 if (fl->fl_u.nfs_fl.state != host->h_state) {
546                         up_read(&host->h_rwsem);
547                         goto again;
548                 }
549                 /* Ensure the resulting lock will get added to granted list */
550                 fl->fl_flags = fl_flags | FL_SLEEP;
551                 if (do_vfs_lock(fl) < 0)
552                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
553                 up_read(&host->h_rwsem);
554         }
555         status = nlm_stat_to_errno(resp->status);
556 out_unblock:
557         nlmclnt_finish_block(block);
558         /* Cancel the blocked request if it is still pending */
559         if (resp->status == NLM_LCK_BLOCKED)
560                 nlmclnt_cancel(host, req->a_args.block, fl);
561 out:
562         nlm_release_call(req);
563         fl->fl_flags = fl_flags;
564         return status;
565 }
566
567 /*
568  * RECLAIM: Try to reclaim a lock
569  */
570 int
571 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
572 {
573         struct nlm_rqst reqst, *req;
574         int             status;
575
576         req = &reqst;
577         memset(req, 0, sizeof(*req));
578         locks_init_lock(&req->a_args.lock.fl);
579         locks_init_lock(&req->a_res.lock.fl);
580         req->a_host  = host;
581         req->a_flags = 0;
582
583         /* Set up the argument struct */
584         nlmclnt_setlockargs(req, fl);
585         req->a_args.reclaim = 1;
586
587         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
588          && req->a_res.status == NLM_LCK_GRANTED)
589                 return 0;
590
591         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
592                                 "(errno %d, status %d)\n", fl->fl_pid,
593                                 status, req->a_res.status);
594
595         /*
596          * FIXME: This is a serious failure. We can
597          *
598          *  a.  Ignore the problem
599          *  b.  Send the owning process some signal (Linux doesn't have
600          *      SIGLOST, though...)
601          *  c.  Retry the operation
602          *
603          * Until someone comes up with a simple implementation
604          * for b or c, I'll choose option a.
605          */
606
607         return -ENOLCK;
608 }
609
610 /*
611  * UNLOCK: remove an existing lock
612  */
613 static int
614 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
615 {
616         struct nlm_host *host = req->a_host;
617         struct nlm_res  *resp = &req->a_res;
618         int status = 0;
619
620         /*
621          * Note: the server is supposed to either grant us the unlock
622          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
623          * case, we want to unlock.
624          */
625         fl->fl_flags |= FL_EXISTS;
626         down_read(&host->h_rwsem);
627         if (do_vfs_lock(fl) == -ENOENT) {
628                 up_read(&host->h_rwsem);
629                 goto out;
630         }
631         up_read(&host->h_rwsem);
632
633         if (req->a_flags & RPC_TASK_ASYNC)
634                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
635
636         status = nlmclnt_call(req, NLMPROC_UNLOCK);
637         if (status < 0)
638                 goto out;
639
640         if (resp->status == NLM_LCK_GRANTED)
641                 goto out;
642
643         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
644                 printk("lockd: unexpected unlock status: %d\n", resp->status);
645         /* What to do now? I'm out of my depth... */
646         status = -ENOLCK;
647 out:
648         nlm_release_call(req);
649         return status;
650 }
651
652 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
653 {
654         struct nlm_rqst *req = data;
655         int             status = req->a_res.status;
656
657         if (RPC_ASSASSINATED(task))
658                 goto die;
659
660         if (task->tk_status < 0) {
661                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
662                 goto retry_rebind;
663         }
664         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
665                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
666                 goto retry_unlock;
667         }
668         if (status != NLM_LCK_GRANTED)
669                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
670 die:
671         return;
672  retry_rebind:
673         nlm_rebind_host(req->a_host);
674  retry_unlock:
675         rpc_restart_call(task);
676 }
677
678 static const struct rpc_call_ops nlmclnt_unlock_ops = {
679         .rpc_call_done = nlmclnt_unlock_callback,
680         .rpc_release = nlmclnt_rpc_release,
681 };
682
683 /*
684  * Cancel a blocked lock request.
685  * We always use an async RPC call for this in order not to hang a
686  * process that has been Ctrl-C'ed.
687  */
688 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
689 {
690         struct nlm_rqst *req;
691         unsigned long   flags;
692         sigset_t        oldset;
693         int             status;
694
695         /* Block all signals while setting up call */
696         spin_lock_irqsave(&current->sighand->siglock, flags);
697         oldset = current->blocked;
698         sigfillset(&current->blocked);
699         recalc_sigpending();
700         spin_unlock_irqrestore(&current->sighand->siglock, flags);
701
702         req = nlm_alloc_call(nlm_get_host(host));
703         if (!req)
704                 return -ENOMEM;
705         req->a_flags = RPC_TASK_ASYNC;
706
707         nlmclnt_setlockargs(req, fl);
708         req->a_args.block = block;
709
710         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
711
712         spin_lock_irqsave(&current->sighand->siglock, flags);
713         current->blocked = oldset;
714         recalc_sigpending();
715         spin_unlock_irqrestore(&current->sighand->siglock, flags);
716
717         return status;
718 }
719
720 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
721 {
722         struct nlm_rqst *req = data;
723
724         if (RPC_ASSASSINATED(task))
725                 goto die;
726
727         if (task->tk_status < 0) {
728                 dprintk("lockd: CANCEL call error %d, retrying.\n",
729                                         task->tk_status);
730                 goto retry_cancel;
731         }
732
733         dprintk("lockd: cancel status %u (task %u)\n",
734                         req->a_res.status, task->tk_pid);
735
736         switch (req->a_res.status) {
737         case NLM_LCK_GRANTED:
738         case NLM_LCK_DENIED_GRACE_PERIOD:
739         case NLM_LCK_DENIED:
740                 /* Everything's good */
741                 break;
742         case NLM_LCK_DENIED_NOLOCKS:
743                 dprintk("lockd: CANCEL failed (server has no locks)\n");
744                 goto retry_cancel;
745         default:
746                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
747                         req->a_res.status);
748         }
749
750 die:
751         return;
752
753 retry_cancel:
754         /* Don't ever retry more than 3 times */
755         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
756                 goto die;
757         nlm_rebind_host(req->a_host);
758         rpc_restart_call(task);
759         rpc_delay(task, 30 * HZ);
760 }
761
762 static const struct rpc_call_ops nlmclnt_cancel_ops = {
763         .rpc_call_done = nlmclnt_cancel_callback,
764         .rpc_release = nlmclnt_rpc_release,
765 };
766
767 /*
768  * Convert an NLM status code to a generic kernel errno
769  */
770 static int
771 nlm_stat_to_errno(u32 status)
772 {
773         switch(status) {
774         case NLM_LCK_GRANTED:
775                 return 0;
776         case NLM_LCK_DENIED:
777                 return -EAGAIN;
778         case NLM_LCK_DENIED_NOLOCKS:
779         case NLM_LCK_DENIED_GRACE_PERIOD:
780                 return -ENOLCK;
781         case NLM_LCK_BLOCKED:
782                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
783                 return -ENOLCK;
784 #ifdef CONFIG_LOCKD_V4
785         case NLM_DEADLCK:
786                 return -EDEADLK;
787         case NLM_ROFS:
788                 return -EROFS;
789         case NLM_STALE_FH:
790                 return -ESTALE;
791         case NLM_FBIG:
792                 return -EOVERFLOW;
793         case NLM_FAILED:
794                 return -ENOLCK;
795 #endif
796         }
797         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
798         return -ENOLCK;
799 }