7a239864b8bfb3377b9a14a3f020eee974269efd
[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/config.h>
10 #include <linux/module.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/smp_lock.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 u32      nlm_cookie = 0x1234;
41
42 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
43 {
44         memcpy(c->data, &nlm_cookie, 4);
45         memset(c->data+4, 0, 4);
46         c->len=4;
47         nlm_cookie++;
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 = (struct nlm_lockowner *)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  = system_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                                 system_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 nfs_server       *nfssrv = NFS_SERVER(inode);
156         struct nlm_host         *host;
157         struct nlm_rqst         reqst, *call = &reqst;
158         sigset_t                oldset;
159         unsigned long           flags;
160         int                     status, proto, vers;
161
162         vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
163         if (NFS_PROTO(inode)->version > 3) {
164                 printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
165                 return -ENOLCK;
166         }
167
168         /* Retrieve transport protocol from NFS client */
169         proto = NFS_CLIENT(inode)->cl_xprt->prot;
170
171         if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
172                 return -ENOLCK;
173
174         /* Create RPC client handle if not there, and copy soft
175          * and intr flags from NFS client. */
176         if (host->h_rpcclnt == NULL) {
177                 struct rpc_clnt *clnt;
178
179                 /* Bind an rpc client to this host handle (does not
180                  * perform a portmapper lookup) */
181                 if (!(clnt = nlm_bind_host(host))) {
182                         status = -ENOLCK;
183                         goto done;
184                 }
185                 clnt->cl_softrtry = nfssrv->client->cl_softrtry;
186                 clnt->cl_intr = nfssrv->client->cl_intr;
187         }
188
189         /* Keep the old signal mask */
190         spin_lock_irqsave(&current->sighand->siglock, flags);
191         oldset = current->blocked;
192
193         /* If we're cleaning up locks because the process is exiting,
194          * perform the RPC call asynchronously. */
195         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
196             && fl->fl_type == F_UNLCK
197             && (current->flags & PF_EXITING)) {
198                 sigfillset(&current->blocked);  /* Mask all signals */
199                 recalc_sigpending();
200                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
201
202                 call = nlmclnt_alloc_call();
203                 if (!call) {
204                         status = -ENOMEM;
205                         goto out_restore;
206                 }
207                 call->a_flags = RPC_TASK_ASYNC;
208         } else {
209                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
210                 memset(call, 0, sizeof(*call));
211                 locks_init_lock(&call->a_args.lock.fl);
212                 locks_init_lock(&call->a_res.lock.fl);
213         }
214         call->a_host = host;
215
216         nlmclnt_locks_init_private(fl, host);
217
218         /* Set up the argument struct */
219         nlmclnt_setlockargs(call, fl);
220
221         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
222                 if (fl->fl_type != F_UNLCK) {
223                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
224                         status = nlmclnt_lock(call, fl);
225                 } else
226                         status = nlmclnt_unlock(call, fl);
227         } else if (IS_GETLK(cmd))
228                 status = nlmclnt_test(call, fl);
229         else
230                 status = -EINVAL;
231
232  out_restore:
233         spin_lock_irqsave(&current->sighand->siglock, flags);
234         current->blocked = oldset;
235         recalc_sigpending();
236         spin_unlock_irqrestore(&current->sighand->siglock, flags);
237
238 done:
239         dprintk("lockd: clnt proc returns %d\n", status);
240         nlm_release_host(host);
241         return status;
242 }
243 EXPORT_SYMBOL(nlmclnt_proc);
244
245 /*
246  * Allocate an NLM RPC call struct
247  */
248 struct nlm_rqst *
249 nlmclnt_alloc_call(void)
250 {
251         struct nlm_rqst *call;
252
253         for(;;) {
254                 call = kzalloc(sizeof(*call), GFP_KERNEL);
255                 if (call != NULL) {
256                         locks_init_lock(&call->a_args.lock.fl);
257                         locks_init_lock(&call->a_res.lock.fl);
258                         return call;
259                 }
260                 if (signalled())
261                         break;
262                 printk("nlmclnt_alloc_call: failed, waiting for memory\n");
263                 schedule_timeout_interruptible(5*HZ);
264         }
265         return NULL;
266 }
267
268 static int nlm_wait_on_grace(wait_queue_head_t *queue)
269 {
270         DEFINE_WAIT(wait);
271         int status = -EINTR;
272
273         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
274         if (!signalled ()) {
275                 schedule_timeout(NLMCLNT_GRACE_WAIT);
276                 try_to_freeze();
277                 if (!signalled ())
278                         status = 0;
279         }
280         finish_wait(queue, &wait);
281         return status;
282 }
283
284 /*
285  * Generic NLM call
286  */
287 static int
288 nlmclnt_call(struct nlm_rqst *req, u32 proc)
289 {
290         struct nlm_host *host = req->a_host;
291         struct rpc_clnt *clnt;
292         struct nlm_args *argp = &req->a_args;
293         struct nlm_res  *resp = &req->a_res;
294         struct rpc_message msg = {
295                 .rpc_argp       = argp,
296                 .rpc_resp       = resp,
297         };
298         int             status;
299
300         dprintk("lockd: call procedure %d on %s\n",
301                         (int)proc, host->h_name);
302
303         do {
304                 if (host->h_reclaiming && !argp->reclaim)
305                         goto in_grace_period;
306
307                 /* If we have no RPC client yet, create one. */
308                 if ((clnt = nlm_bind_host(host)) == NULL)
309                         return -ENOLCK;
310                 msg.rpc_proc = &clnt->cl_procinfo[proc];
311
312                 /* Perform the RPC call. If an error occurs, try again */
313                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
314                         dprintk("lockd: rpc_call returned error %d\n", -status);
315                         switch (status) {
316                         case -EPROTONOSUPPORT:
317                                 status = -EINVAL;
318                                 break;
319                         case -ECONNREFUSED:
320                         case -ETIMEDOUT:
321                         case -ENOTCONN:
322                                 nlm_rebind_host(host);
323                                 status = -EAGAIN;
324                                 break;
325                         case -ERESTARTSYS:
326                                 return signalled () ? -EINTR : status;
327                         default:
328                                 break;
329                         }
330                         break;
331                 } else
332                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
333                         dprintk("lockd: server in grace period\n");
334                         if (argp->reclaim) {
335                                 printk(KERN_WARNING
336                                      "lockd: spurious grace period reject?!\n");
337                                 return -ENOLCK;
338                         }
339                 } else {
340                         if (!argp->reclaim) {
341                                 /* We appear to be out of the grace period */
342                                 wake_up_all(&host->h_gracewait);
343                         }
344                         dprintk("lockd: server returns status %d\n", resp->status);
345                         return 0;       /* Okay, call complete */
346                 }
347
348 in_grace_period:
349                 /*
350                  * The server has rebooted and appears to be in the grace
351                  * period during which locks are only allowed to be
352                  * reclaimed.
353                  * We can only back off and try again later.
354                  */
355                 status = nlm_wait_on_grace(&host->h_gracewait);
356         } while (status == 0);
357
358         return status;
359 }
360
361 /*
362  * Generic NLM call, async version.
363  */
364 int nlmsvc_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
365 {
366         struct nlm_host *host = req->a_host;
367         struct rpc_clnt *clnt;
368         struct rpc_message msg = {
369                 .rpc_argp       = &req->a_args,
370                 .rpc_resp       = &req->a_res,
371         };
372         int             status;
373
374         dprintk("lockd: call procedure %d on %s (async)\n",
375                         (int)proc, host->h_name);
376
377         /* If we have no RPC client yet, create one. */
378         if ((clnt = nlm_bind_host(host)) == NULL)
379                 return -ENOLCK;
380         msg.rpc_proc = &clnt->cl_procinfo[proc];
381
382         /* bootstrap and kick off the async RPC call */
383         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
384
385         return status;
386 }
387
388 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
389 {
390         struct nlm_host *host = req->a_host;
391         struct rpc_clnt *clnt;
392         struct nlm_args *argp = &req->a_args;
393         struct nlm_res  *resp = &req->a_res;
394         struct rpc_message msg = {
395                 .rpc_argp       = argp,
396                 .rpc_resp       = resp,
397         };
398         int             status;
399
400         dprintk("lockd: call procedure %d on %s (async)\n",
401                         (int)proc, host->h_name);
402
403         /* If we have no RPC client yet, create one. */
404         if ((clnt = nlm_bind_host(host)) == NULL)
405                 return -ENOLCK;
406         msg.rpc_proc = &clnt->cl_procinfo[proc];
407
408         /* Increment host refcount */
409         nlm_get_host(host);
410         /* bootstrap and kick off the async RPC call */
411         status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
412         if (status < 0)
413                 nlm_release_host(host);
414         return status;
415 }
416
417 /*
418  * TEST for the presence of a conflicting lock
419  */
420 static int
421 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
422 {
423         int     status;
424
425         status = nlmclnt_call(req, NLMPROC_TEST);
426         nlmclnt_release_lockargs(req);
427         if (status < 0)
428                 return status;
429
430         status = req->a_res.status;
431         if (status == NLM_LCK_GRANTED) {
432                 fl->fl_type = F_UNLCK;
433         } if (status == NLM_LCK_DENIED) {
434                 /*
435                  * Report the conflicting lock back to the application.
436                  */
437                 fl->fl_start = req->a_res.lock.fl.fl_start;
438                 fl->fl_end = req->a_res.lock.fl.fl_start;
439                 fl->fl_type = req->a_res.lock.fl.fl_type;
440                 fl->fl_pid = 0;
441         } else {
442                 return nlm_stat_to_errno(req->a_res.status);
443         }
444
445         return 0;
446 }
447
448 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
449 {
450         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
451         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
452         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
453 }
454
455 static void nlmclnt_locks_release_private(struct file_lock *fl)
456 {
457         list_del(&fl->fl_u.nfs_fl.list);
458         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
459 }
460
461 static struct file_lock_operations nlmclnt_lock_ops = {
462         .fl_copy_lock = nlmclnt_locks_copy_lock,
463         .fl_release_private = nlmclnt_locks_release_private,
464 };
465
466 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
467 {
468         BUG_ON(fl->fl_ops != NULL);
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 void 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         if (res < 0)
489                 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
490                                 __FUNCTION__);
491 }
492
493 /*
494  * LOCK: Try to create a lock
495  *
496  *                      Programmer Harassment Alert
497  *
498  * When given a blocking lock request in a sync RPC call, the HPUX lockd
499  * will faithfully return LCK_BLOCKED but never cares to notify us when
500  * the lock could be granted. This way, our local process could hang
501  * around forever waiting for the callback.
502  *
503  *  Solution A: Implement busy-waiting
504  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
505  *
506  * For now I am implementing solution A, because I hate the idea of
507  * re-implementing lockd for a third time in two months. The async
508  * calls shouldn't be too hard to do, however.
509  *
510  * This is one of the lovely things about standards in the NFS area:
511  * they're so soft and squishy you can't really blame HP for doing this.
512  */
513 static int
514 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
515 {
516         struct nlm_host *host = req->a_host;
517         struct nlm_res  *resp = &req->a_res;
518         struct nlm_wait *block = NULL;
519         int status = -ENOLCK;
520
521         if (!host->h_monitored && nsm_monitor(host) < 0) {
522                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
523                                         host->h_name);
524                 goto out;
525         }
526
527         block = nlmclnt_prepare_block(host, fl);
528         for(;;) {
529                 status = nlmclnt_call(req, NLMPROC_LOCK);
530                 if (status < 0)
531                         goto out_unblock;
532                 if (!req->a_args.block)
533                         break;
534                 /* Did a reclaimer thread notify us of a server reboot? */
535                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
536                         continue;
537                 if (resp->status != NLM_LCK_BLOCKED)
538                         break;
539                 /* Wait on an NLM blocking lock */
540                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
541                 /* if we were interrupted. Send a CANCEL request to the server
542                  * and exit
543                  */
544                 if (status < 0)
545                         goto out_unblock;
546                 if (resp->status != NLM_LCK_BLOCKED)
547                         break;
548         }
549
550         if (resp->status == NLM_LCK_GRANTED) {
551                 fl->fl_u.nfs_fl.state = host->h_state;
552                 fl->fl_flags |= FL_SLEEP;
553                 /* Ensure the resulting lock will get added to granted list */
554                 do_vfs_lock(fl);
555         }
556         status = nlm_stat_to_errno(resp->status);
557 out_unblock:
558         nlmclnt_finish_block(block);
559         /* Cancel the blocked request if it is still pending */
560         if (resp->status == NLM_LCK_BLOCKED)
561                 nlmclnt_cancel(host, req->a_args.block, fl);
562 out:
563         nlmclnt_release_lockargs(req);
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_res  *resp = &req->a_res;
617         int             status;
618
619         /*
620          * Note: the server is supposed to either grant us the unlock
621          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
622          * case, we want to unlock.
623          */
624         do_vfs_lock(fl);
625
626         if (req->a_flags & RPC_TASK_ASYNC) {
627                 status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
628                                         &nlmclnt_unlock_ops);
629                 /* Hrmf... Do the unlock early since locks_remove_posix()
630                  * really expects us to free the lock synchronously */
631                 if (status < 0) {
632                         nlmclnt_release_lockargs(req);
633                         kfree(req);
634                 }
635                 return status;
636         }
637
638         status = nlmclnt_call(req, NLMPROC_UNLOCK);
639         nlmclnt_release_lockargs(req);
640         if (status < 0)
641                 return status;
642
643         if (resp->status == NLM_LCK_GRANTED)
644                 return 0;
645
646         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
647                 printk("lockd: unexpected unlock status: %d\n", resp->status);
648
649         /* What to do now? I'm out of my depth... */
650
651         return -ENOLCK;
652 }
653
654 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
655 {
656         struct nlm_rqst *req = data;
657         int             status = req->a_res.status;
658
659         if (RPC_ASSASSINATED(task))
660                 goto die;
661
662         if (task->tk_status < 0) {
663                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
664                 goto retry_rebind;
665         }
666         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
667                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
668                 goto retry_unlock;
669         }
670         if (status != NLM_LCK_GRANTED)
671                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
672 die:
673         nlm_release_host(req->a_host);
674         nlmclnt_release_lockargs(req);
675         kfree(req);
676         return;
677  retry_rebind:
678         nlm_rebind_host(req->a_host);
679  retry_unlock:
680         rpc_restart_call(task);
681 }
682
683 static const struct rpc_call_ops nlmclnt_unlock_ops = {
684         .rpc_call_done = nlmclnt_unlock_callback,
685 };
686
687 /*
688  * Cancel a blocked lock request.
689  * We always use an async RPC call for this in order not to hang a
690  * process that has been Ctrl-C'ed.
691  */
692 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
693 {
694         struct nlm_rqst *req;
695         unsigned long   flags;
696         sigset_t        oldset;
697         int             status;
698
699         /* Block all signals while setting up call */
700         spin_lock_irqsave(&current->sighand->siglock, flags);
701         oldset = current->blocked;
702         sigfillset(&current->blocked);
703         recalc_sigpending();
704         spin_unlock_irqrestore(&current->sighand->siglock, flags);
705
706         req = nlmclnt_alloc_call();
707         if (!req)
708                 return -ENOMEM;
709         req->a_host  = host;
710         req->a_flags = RPC_TASK_ASYNC;
711
712         nlmclnt_setlockargs(req, fl);
713         req->a_args.block = block;
714
715         status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
716         if (status < 0) {
717                 nlmclnt_release_lockargs(req);
718                 kfree(req);
719         }
720
721         spin_lock_irqsave(&current->sighand->siglock, flags);
722         current->blocked = oldset;
723         recalc_sigpending();
724         spin_unlock_irqrestore(&current->sighand->siglock, flags);
725
726         return status;
727 }
728
729 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
730 {
731         struct nlm_rqst *req = data;
732
733         if (RPC_ASSASSINATED(task))
734                 goto die;
735
736         if (task->tk_status < 0) {
737                 dprintk("lockd: CANCEL call error %d, retrying.\n",
738                                         task->tk_status);
739                 goto retry_cancel;
740         }
741
742         dprintk("lockd: cancel status %d (task %d)\n",
743                         req->a_res.status, task->tk_pid);
744
745         switch (req->a_res.status) {
746         case NLM_LCK_GRANTED:
747         case NLM_LCK_DENIED_GRACE_PERIOD:
748         case NLM_LCK_DENIED:
749                 /* Everything's good */
750                 break;
751         case NLM_LCK_DENIED_NOLOCKS:
752                 dprintk("lockd: CANCEL failed (server has no locks)\n");
753                 goto retry_cancel;
754         default:
755                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
756                         req->a_res.status);
757         }
758
759 die:
760         nlm_release_host(req->a_host);
761         nlmclnt_release_lockargs(req);
762         kfree(req);
763         return;
764
765 retry_cancel:
766         /* Don't ever retry more than 3 times */
767         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
768                 goto die;
769         nlm_rebind_host(req->a_host);
770         rpc_restart_call(task);
771         rpc_delay(task, 30 * HZ);
772 }
773
774 static const struct rpc_call_ops nlmclnt_cancel_ops = {
775         .rpc_call_done = nlmclnt_cancel_callback,
776 };
777
778 /*
779  * Convert an NLM status code to a generic kernel errno
780  */
781 static int
782 nlm_stat_to_errno(u32 status)
783 {
784         switch(status) {
785         case NLM_LCK_GRANTED:
786                 return 0;
787         case NLM_LCK_DENIED:
788                 return -EAGAIN;
789         case NLM_LCK_DENIED_NOLOCKS:
790         case NLM_LCK_DENIED_GRACE_PERIOD:
791                 return -ENOLCK;
792         case NLM_LCK_BLOCKED:
793                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
794                 return -ENOLCK;
795 #ifdef CONFIG_LOCKD_V4
796         case NLM_DEADLCK:
797                 return -EDEADLK;
798         case NLM_ROFS:
799                 return -EROFS;
800         case NLM_STALE_FH:
801                 return -ESTALE;
802         case NLM_FBIG:
803                 return -EOVERFLOW;
804         case NLM_FAILED:
805                 return -ENOLCK;
806 #endif
807         }
808         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
809         return -ENOLCK;
810 }