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[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/sunrpc/clnt.h>
17 #include <linux/sunrpc/svc.h>
18 #include <linux/lockd/lockd.h>
19 #include <linux/lockd/sm_inter.h>
20
21 #define NLMDBG_FACILITY         NLMDBG_CLIENT
22 #define NLMCLNT_GRACE_WAIT      (5*HZ)
23 #define NLMCLNT_POLL_TIMEOUT    (30*HZ)
24 #define NLMCLNT_MAX_RETRIES     3
25
26 static int      nlmclnt_test(struct nlm_rqst *, struct file_lock *);
27 static int      nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
28 static int      nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
29 static int      nlm_stat_to_errno(u32 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 u32      nlm_cookie = 0x1234;
40
41 static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
42 {
43         memcpy(c->data, &nlm_cookie, 4);
44         memset(c->data+4, 0, 4);
45         c->len=4;
46         nlm_cookie++;
47 }
48
49 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
50 {
51         atomic_inc(&lockowner->count);
52         return lockowner;
53 }
54
55 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
56 {
57         if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
58                 return;
59         list_del(&lockowner->list);
60         spin_unlock(&lockowner->host->h_lock);
61         nlm_release_host(lockowner->host);
62         kfree(lockowner);
63 }
64
65 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
66 {
67         struct nlm_lockowner *lockowner;
68         list_for_each_entry(lockowner, &host->h_lockowners, list) {
69                 if (lockowner->pid == pid)
70                         return -EBUSY;
71         }
72         return 0;
73 }
74
75 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
76 {
77         uint32_t res;
78         do {
79                 res = host->h_pidcount++;
80         } while (nlm_pidbusy(host, res) < 0);
81         return res;
82 }
83
84 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
85 {
86         struct nlm_lockowner *lockowner;
87         list_for_each_entry(lockowner, &host->h_lockowners, list) {
88                 if (lockowner->owner != owner)
89                         continue;
90                 return nlm_get_lockowner(lockowner);
91         }
92         return NULL;
93 }
94
95 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
96 {
97         struct nlm_lockowner *res, *new = NULL;
98
99         spin_lock(&host->h_lock);
100         res = __nlm_find_lockowner(host, owner);
101         if (res == NULL) {
102                 spin_unlock(&host->h_lock);
103                 new = kmalloc(sizeof(*new), GFP_KERNEL);
104                 spin_lock(&host->h_lock);
105                 res = __nlm_find_lockowner(host, owner);
106                 if (res == NULL && new != NULL) {
107                         res = new;
108                         atomic_set(&new->count, 1);
109                         new->owner = owner;
110                         new->pid = __nlm_alloc_pid(host);
111                         new->host = nlm_get_host(host);
112                         list_add(&new->list, &host->h_lockowners);
113                         new = NULL;
114                 }
115         }
116         spin_unlock(&host->h_lock);
117         kfree(new);
118         return res;
119 }
120
121 /*
122  * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
123  */
124 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
125 {
126         struct nlm_args *argp = &req->a_args;
127         struct nlm_lock *lock = &argp->lock;
128
129         nlmclnt_next_cookie(&argp->cookie);
130         argp->state   = nsm_local_state;
131         memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
132         lock->caller  = utsname()->nodename;
133         lock->oh.data = req->a_owner;
134         lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
135                                 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
136                                 utsname()->nodename);
137         lock->svid = fl->fl_u.nfs_fl.owner->pid;
138         lock->fl.fl_start = fl->fl_start;
139         lock->fl.fl_end = fl->fl_end;
140         lock->fl.fl_type = fl->fl_type;
141 }
142
143 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
144 {
145         BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
146 }
147
148 /*
149  * This is the main entry point for the NLM client.
150  */
151 int
152 nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
153 {
154         struct rpc_clnt         *client = NFS_CLIENT(inode);
155         struct sockaddr_in      addr;
156         struct nlm_host         *host;
157         struct nlm_rqst         *call;
158         sigset_t                oldset;
159         unsigned long           flags;
160         int                     status, 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         rpc_peeraddr(client, (struct sockaddr *) &addr, sizeof(addr));
169         host = nlmclnt_lookup_host(&addr, client->cl_xprt->prot, vers);
170         if (host == NULL)
171                 return -ENOLCK;
172
173         call = nlm_alloc_call(host);
174         if (call == NULL)
175                 return -ENOMEM;
176
177         nlmclnt_locks_init_private(fl, host);
178         /* Set up the argument struct */
179         nlmclnt_setlockargs(call, fl);
180
181         /* Keep the old signal mask */
182         spin_lock_irqsave(&current->sighand->siglock, flags);
183         oldset = current->blocked;
184
185         /* If we're cleaning up locks because the process is exiting,
186          * perform the RPC call asynchronously. */
187         if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
188             && fl->fl_type == F_UNLCK
189             && (current->flags & PF_EXITING)) {
190                 sigfillset(&current->blocked);  /* Mask all signals */
191                 recalc_sigpending();
192
193                 call->a_flags = RPC_TASK_ASYNC;
194         }
195         spin_unlock_irqrestore(&current->sighand->siglock, flags);
196
197         if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
198                 if (fl->fl_type != F_UNLCK) {
199                         call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
200                         status = nlmclnt_lock(call, fl);
201                 } else
202                         status = nlmclnt_unlock(call, fl);
203         } else if (IS_GETLK(cmd))
204                 status = nlmclnt_test(call, fl);
205         else
206                 status = -EINVAL;
207
208         fl->fl_ops->fl_release_private(fl);
209         fl->fl_ops = NULL;
210
211         spin_lock_irqsave(&current->sighand->siglock, flags);
212         current->blocked = oldset;
213         recalc_sigpending();
214         spin_unlock_irqrestore(&current->sighand->siglock, flags);
215
216         dprintk("lockd: clnt proc returns %d\n", status);
217         return status;
218 }
219 EXPORT_SYMBOL(nlmclnt_proc);
220
221 /*
222  * Allocate an NLM RPC call struct
223  *
224  * Note: the caller must hold a reference to host. In case of failure,
225  * this reference will be released.
226  */
227 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
228 {
229         struct nlm_rqst *call;
230
231         for(;;) {
232                 call = kzalloc(sizeof(*call), GFP_KERNEL);
233                 if (call != NULL) {
234                         locks_init_lock(&call->a_args.lock.fl);
235                         locks_init_lock(&call->a_res.lock.fl);
236                         call->a_host = host;
237                         return call;
238                 }
239                 if (signalled())
240                         break;
241                 printk("nlm_alloc_call: failed, waiting for memory\n");
242                 schedule_timeout_interruptible(5*HZ);
243         }
244         nlm_release_host(host);
245         return NULL;
246 }
247
248 void nlm_release_call(struct nlm_rqst *call)
249 {
250         nlm_release_host(call->a_host);
251         nlmclnt_release_lockargs(call);
252         kfree(call);
253 }
254
255 static void nlmclnt_rpc_release(void *data)
256 {
257         return nlm_release_call(data);
258 }
259
260 static int nlm_wait_on_grace(wait_queue_head_t *queue)
261 {
262         DEFINE_WAIT(wait);
263         int status = -EINTR;
264
265         prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
266         if (!signalled ()) {
267                 schedule_timeout(NLMCLNT_GRACE_WAIT);
268                 try_to_freeze();
269                 if (!signalled ())
270                         status = 0;
271         }
272         finish_wait(queue, &wait);
273         return status;
274 }
275
276 /*
277  * Generic NLM call
278  */
279 static int
280 nlmclnt_call(struct nlm_rqst *req, u32 proc)
281 {
282         struct nlm_host *host = req->a_host;
283         struct rpc_clnt *clnt;
284         struct nlm_args *argp = &req->a_args;
285         struct nlm_res  *resp = &req->a_res;
286         struct rpc_message msg = {
287                 .rpc_argp       = argp,
288                 .rpc_resp       = resp,
289         };
290         int             status;
291
292         dprintk("lockd: call procedure %d on %s\n",
293                         (int)proc, host->h_name);
294
295         do {
296                 if (host->h_reclaiming && !argp->reclaim)
297                         goto in_grace_period;
298
299                 /* If we have no RPC client yet, create one. */
300                 if ((clnt = nlm_bind_host(host)) == NULL)
301                         return -ENOLCK;
302                 msg.rpc_proc = &clnt->cl_procinfo[proc];
303
304                 /* Perform the RPC call. If an error occurs, try again */
305                 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
306                         dprintk("lockd: rpc_call returned error %d\n", -status);
307                         switch (status) {
308                         case -EPROTONOSUPPORT:
309                                 status = -EINVAL;
310                                 break;
311                         case -ECONNREFUSED:
312                         case -ETIMEDOUT:
313                         case -ENOTCONN:
314                                 nlm_rebind_host(host);
315                                 status = -EAGAIN;
316                                 break;
317                         case -ERESTARTSYS:
318                                 return signalled () ? -EINTR : status;
319                         default:
320                                 break;
321                         }
322                         break;
323                 } else
324                 if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
325                         dprintk("lockd: server in grace period\n");
326                         if (argp->reclaim) {
327                                 printk(KERN_WARNING
328                                      "lockd: spurious grace period reject?!\n");
329                                 return -ENOLCK;
330                         }
331                 } else {
332                         if (!argp->reclaim) {
333                                 /* We appear to be out of the grace period */
334                                 wake_up_all(&host->h_gracewait);
335                         }
336                         dprintk("lockd: server returns status %d\n", resp->status);
337                         return 0;       /* Okay, call complete */
338                 }
339
340 in_grace_period:
341                 /*
342                  * The server has rebooted and appears to be in the grace
343                  * period during which locks are only allowed to be
344                  * reclaimed.
345                  * We can only back off and try again later.
346                  */
347                 status = nlm_wait_on_grace(&host->h_gracewait);
348         } while (status == 0);
349
350         return status;
351 }
352
353 /*
354  * Generic NLM call, async version.
355  */
356 static int __nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
357 {
358         struct nlm_host *host = req->a_host;
359         struct rpc_clnt *clnt;
360         int status = -ENOLCK;
361
362         dprintk("lockd: call procedure %d on %s (async)\n",
363                         (int)proc, host->h_name);
364
365         /* If we have no RPC client yet, create one. */
366         clnt = nlm_bind_host(host);
367         if (clnt == NULL)
368                 goto out_err;
369         msg->rpc_proc = &clnt->cl_procinfo[proc];
370
371         /* bootstrap and kick off the async RPC call */
372         status = rpc_call_async(clnt, msg, RPC_TASK_ASYNC, tk_ops, req);
373         if (status == 0)
374                 return 0;
375 out_err:
376         nlm_release_call(req);
377         return status;
378 }
379
380 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
381 {
382         struct rpc_message msg = {
383                 .rpc_argp       = &req->a_args,
384                 .rpc_resp       = &req->a_res,
385         };
386         return __nlm_async_call(req, proc, &msg, tk_ops);
387 }
388
389 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
390 {
391         struct rpc_message msg = {
392                 .rpc_argp       = &req->a_res,
393         };
394         return __nlm_async_call(req, proc, &msg, tk_ops);
395 }
396
397 /*
398  * TEST for the presence of a conflicting lock
399  */
400 static int
401 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
402 {
403         int     status;
404
405         status = nlmclnt_call(req, NLMPROC_TEST);
406         if (status < 0)
407                 goto out;
408
409         switch (req->a_res.status) {
410                 case NLM_LCK_GRANTED:
411                         fl->fl_type = F_UNLCK;
412                         break;
413                 case NLM_LCK_DENIED:
414                         /*
415                          * Report the conflicting lock back to the application.
416                          */
417                         fl->fl_start = req->a_res.lock.fl.fl_start;
418                         fl->fl_end = req->a_res.lock.fl.fl_start;
419                         fl->fl_type = req->a_res.lock.fl.fl_type;
420                         fl->fl_pid = 0;
421                         break;
422                 default:
423                         status = nlm_stat_to_errno(req->a_res.status);
424         }
425 out:
426         nlm_release_call(req);
427         return status;
428 }
429
430 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
431 {
432         new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
433         new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
434         list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
435 }
436
437 static void nlmclnt_locks_release_private(struct file_lock *fl)
438 {
439         list_del(&fl->fl_u.nfs_fl.list);
440         nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
441 }
442
443 static struct file_lock_operations nlmclnt_lock_ops = {
444         .fl_copy_lock = nlmclnt_locks_copy_lock,
445         .fl_release_private = nlmclnt_locks_release_private,
446 };
447
448 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
449 {
450         BUG_ON(fl->fl_ops != NULL);
451         fl->fl_u.nfs_fl.state = 0;
452         fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
453         INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
454         fl->fl_ops = &nlmclnt_lock_ops;
455 }
456
457 static int do_vfs_lock(struct file_lock *fl)
458 {
459         int res = 0;
460         switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
461                 case FL_POSIX:
462                         res = posix_lock_file_wait(fl->fl_file, fl);
463                         break;
464                 case FL_FLOCK:
465                         res = flock_lock_file_wait(fl->fl_file, fl);
466                         break;
467                 default:
468                         BUG();
469         }
470         return res;
471 }
472
473 /*
474  * LOCK: Try to create a lock
475  *
476  *                      Programmer Harassment Alert
477  *
478  * When given a blocking lock request in a sync RPC call, the HPUX lockd
479  * will faithfully return LCK_BLOCKED but never cares to notify us when
480  * the lock could be granted. This way, our local process could hang
481  * around forever waiting for the callback.
482  *
483  *  Solution A: Implement busy-waiting
484  *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
485  *
486  * For now I am implementing solution A, because I hate the idea of
487  * re-implementing lockd for a third time in two months. The async
488  * calls shouldn't be too hard to do, however.
489  *
490  * This is one of the lovely things about standards in the NFS area:
491  * they're so soft and squishy you can't really blame HP for doing this.
492  */
493 static int
494 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
495 {
496         struct nlm_host *host = req->a_host;
497         struct nlm_res  *resp = &req->a_res;
498         struct nlm_wait *block = NULL;
499         unsigned char fl_flags = fl->fl_flags;
500         int status = -ENOLCK;
501
502         if (!host->h_monitored && nsm_monitor(host) < 0) {
503                 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
504                                         host->h_name);
505                 goto out;
506         }
507         fl->fl_flags |= FL_ACCESS;
508         status = do_vfs_lock(fl);
509         if (status < 0)
510                 goto out;
511
512         block = nlmclnt_prepare_block(host, fl);
513 again:
514         for(;;) {
515                 /* Reboot protection */
516                 fl->fl_u.nfs_fl.state = host->h_state;
517                 status = nlmclnt_call(req, NLMPROC_LOCK);
518                 if (status < 0)
519                         goto out_unblock;
520                 if (!req->a_args.block)
521                         break;
522                 /* Did a reclaimer thread notify us of a server reboot? */
523                 if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
524                         continue;
525                 if (resp->status != NLM_LCK_BLOCKED)
526                         break;
527                 /* Wait on an NLM blocking lock */
528                 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
529                 /* if we were interrupted. Send a CANCEL request to the server
530                  * and exit
531                  */
532                 if (status < 0)
533                         goto out_unblock;
534                 if (resp->status != NLM_LCK_BLOCKED)
535                         break;
536         }
537
538         if (resp->status == NLM_LCK_GRANTED) {
539                 down_read(&host->h_rwsem);
540                 /* Check whether or not the server has rebooted */
541                 if (fl->fl_u.nfs_fl.state != host->h_state) {
542                         up_read(&host->h_rwsem);
543                         goto again;
544                 }
545                 /* Ensure the resulting lock will get added to granted list */
546                 fl->fl_flags = fl_flags | FL_SLEEP;
547                 if (do_vfs_lock(fl) < 0)
548                         printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
549                 up_read(&host->h_rwsem);
550         }
551         status = nlm_stat_to_errno(resp->status);
552 out_unblock:
553         nlmclnt_finish_block(block);
554         /* Cancel the blocked request if it is still pending */
555         if (resp->status == NLM_LCK_BLOCKED)
556                 nlmclnt_cancel(host, req->a_args.block, fl);
557 out:
558         nlm_release_call(req);
559         fl->fl_flags = fl_flags;
560         return status;
561 }
562
563 /*
564  * RECLAIM: Try to reclaim a lock
565  */
566 int
567 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
568 {
569         struct nlm_rqst reqst, *req;
570         int             status;
571
572         req = &reqst;
573         memset(req, 0, sizeof(*req));
574         locks_init_lock(&req->a_args.lock.fl);
575         locks_init_lock(&req->a_res.lock.fl);
576         req->a_host  = host;
577         req->a_flags = 0;
578
579         /* Set up the argument struct */
580         nlmclnt_setlockargs(req, fl);
581         req->a_args.reclaim = 1;
582
583         if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
584          && req->a_res.status == NLM_LCK_GRANTED)
585                 return 0;
586
587         printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
588                                 "(errno %d, status %d)\n", fl->fl_pid,
589                                 status, req->a_res.status);
590
591         /*
592          * FIXME: This is a serious failure. We can
593          *
594          *  a.  Ignore the problem
595          *  b.  Send the owning process some signal (Linux doesn't have
596          *      SIGLOST, though...)
597          *  c.  Retry the operation
598          *
599          * Until someone comes up with a simple implementation
600          * for b or c, I'll choose option a.
601          */
602
603         return -ENOLCK;
604 }
605
606 /*
607  * UNLOCK: remove an existing lock
608  */
609 static int
610 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
611 {
612         struct nlm_host *host = req->a_host;
613         struct nlm_res  *resp = &req->a_res;
614         int status = 0;
615
616         /*
617          * Note: the server is supposed to either grant us the unlock
618          * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
619          * case, we want to unlock.
620          */
621         fl->fl_flags |= FL_EXISTS;
622         down_read(&host->h_rwsem);
623         if (do_vfs_lock(fl) == -ENOENT) {
624                 up_read(&host->h_rwsem);
625                 goto out;
626         }
627         up_read(&host->h_rwsem);
628
629         if (req->a_flags & RPC_TASK_ASYNC)
630                 return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
631
632         status = nlmclnt_call(req, NLMPROC_UNLOCK);
633         if (status < 0)
634                 goto out;
635
636         if (resp->status == NLM_LCK_GRANTED)
637                 goto out;
638
639         if (resp->status != NLM_LCK_DENIED_NOLOCKS)
640                 printk("lockd: unexpected unlock status: %d\n", resp->status);
641         /* What to do now? I'm out of my depth... */
642         status = -ENOLCK;
643 out:
644         nlm_release_call(req);
645         return status;
646 }
647
648 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
649 {
650         struct nlm_rqst *req = data;
651         int             status = req->a_res.status;
652
653         if (RPC_ASSASSINATED(task))
654                 goto die;
655
656         if (task->tk_status < 0) {
657                 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
658                 goto retry_rebind;
659         }
660         if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
661                 rpc_delay(task, NLMCLNT_GRACE_WAIT);
662                 goto retry_unlock;
663         }
664         if (status != NLM_LCK_GRANTED)
665                 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
666 die:
667         return;
668  retry_rebind:
669         nlm_rebind_host(req->a_host);
670  retry_unlock:
671         rpc_restart_call(task);
672 }
673
674 static const struct rpc_call_ops nlmclnt_unlock_ops = {
675         .rpc_call_done = nlmclnt_unlock_callback,
676         .rpc_release = nlmclnt_rpc_release,
677 };
678
679 /*
680  * Cancel a blocked lock request.
681  * We always use an async RPC call for this in order not to hang a
682  * process that has been Ctrl-C'ed.
683  */
684 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
685 {
686         struct nlm_rqst *req;
687         unsigned long   flags;
688         sigset_t        oldset;
689         int             status;
690
691         /* Block all signals while setting up call */
692         spin_lock_irqsave(&current->sighand->siglock, flags);
693         oldset = current->blocked;
694         sigfillset(&current->blocked);
695         recalc_sigpending();
696         spin_unlock_irqrestore(&current->sighand->siglock, flags);
697
698         req = nlm_alloc_call(nlm_get_host(host));
699         if (!req)
700                 return -ENOMEM;
701         req->a_flags = RPC_TASK_ASYNC;
702
703         nlmclnt_setlockargs(req, fl);
704         req->a_args.block = block;
705
706         status = nlm_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
707
708         spin_lock_irqsave(&current->sighand->siglock, flags);
709         current->blocked = oldset;
710         recalc_sigpending();
711         spin_unlock_irqrestore(&current->sighand->siglock, flags);
712
713         return status;
714 }
715
716 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
717 {
718         struct nlm_rqst *req = data;
719
720         if (RPC_ASSASSINATED(task))
721                 goto die;
722
723         if (task->tk_status < 0) {
724                 dprintk("lockd: CANCEL call error %d, retrying.\n",
725                                         task->tk_status);
726                 goto retry_cancel;
727         }
728
729         dprintk("lockd: cancel status %d (task %d)\n",
730                         req->a_res.status, task->tk_pid);
731
732         switch (req->a_res.status) {
733         case NLM_LCK_GRANTED:
734         case NLM_LCK_DENIED_GRACE_PERIOD:
735         case NLM_LCK_DENIED:
736                 /* Everything's good */
737                 break;
738         case NLM_LCK_DENIED_NOLOCKS:
739                 dprintk("lockd: CANCEL failed (server has no locks)\n");
740                 goto retry_cancel;
741         default:
742                 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
743                         req->a_res.status);
744         }
745
746 die:
747         return;
748
749 retry_cancel:
750         /* Don't ever retry more than 3 times */
751         if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
752                 goto die;
753         nlm_rebind_host(req->a_host);
754         rpc_restart_call(task);
755         rpc_delay(task, 30 * HZ);
756 }
757
758 static const struct rpc_call_ops nlmclnt_cancel_ops = {
759         .rpc_call_done = nlmclnt_cancel_callback,
760         .rpc_release = nlmclnt_rpc_release,
761 };
762
763 /*
764  * Convert an NLM status code to a generic kernel errno
765  */
766 static int
767 nlm_stat_to_errno(u32 status)
768 {
769         switch(status) {
770         case NLM_LCK_GRANTED:
771                 return 0;
772         case NLM_LCK_DENIED:
773                 return -EAGAIN;
774         case NLM_LCK_DENIED_NOLOCKS:
775         case NLM_LCK_DENIED_GRACE_PERIOD:
776                 return -ENOLCK;
777         case NLM_LCK_BLOCKED:
778                 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
779                 return -ENOLCK;
780 #ifdef CONFIG_LOCKD_V4
781         case NLM_DEADLCK:
782                 return -EDEADLK;
783         case NLM_ROFS:
784                 return -EROFS;
785         case NLM_STALE_FH:
786                 return -ESTALE;
787         case NLM_FBIG:
788                 return -EOVERFLOW;
789         case NLM_FAILED:
790                 return -ENOLCK;
791 #endif
792         }
793         printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
794         return -ENOLCK;
795 }