RPC: Clean up RPC task structure
[linux-2.6.git] / fs / lockd / svclock.c
1 /*
2  * linux/fs/lockd/svclock.c
3  *
4  * Handling of server-side locks, mostly of the blocked variety.
5  * This is the ugliest part of lockd because we tread on very thin ice.
6  * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc.
7  * IMNSHO introducing the grant callback into the NLM protocol was one
8  * of the worst ideas Sun ever had. Except maybe for the idea of doing
9  * NFS file locking at all.
10  *
11  * I'm trying hard to avoid race conditions by protecting most accesses
12  * to a file's list of blocked locks through a semaphore. The global
13  * list of blocked locks is not protected in this fashion however.
14  * Therefore, some functions (such as the RPC callback for the async grant
15  * call) move blocked locks towards the head of the list *while some other
16  * process might be traversing it*. This should not be a problem in
17  * practice, because this will only cause functions traversing the list
18  * to visit some blocks twice.
19  *
20  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
21  */
22
23 #include <linux/config.h>
24 #include <linux/types.h>
25 #include <linux/errno.h>
26 #include <linux/kernel.h>
27 #include <linux/sched.h>
28 #include <linux/smp_lock.h>
29 #include <linux/sunrpc/clnt.h>
30 #include <linux/sunrpc/svc.h>
31 #include <linux/lockd/nlm.h>
32 #include <linux/lockd/lockd.h>
33
34 #define NLMDBG_FACILITY         NLMDBG_SVCLOCK
35
36 #ifdef CONFIG_LOCKD_V4
37 #define nlm_deadlock    nlm4_deadlock
38 #else
39 #define nlm_deadlock    nlm_lck_denied
40 #endif
41
42 static void     nlmsvc_insert_block(struct nlm_block *block, unsigned long);
43 static int      nlmsvc_remove_block(struct nlm_block *block);
44
45 static const struct rpc_call_ops nlmsvc_grant_ops;
46
47 /*
48  * The list of blocked locks to retry
49  */
50 static struct nlm_block *       nlm_blocked;
51
52 /*
53  * Insert a blocked lock into the global list
54  */
55 static void
56 nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
57 {
58         struct nlm_block **bp, *b;
59
60         dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
61         if (block->b_queued)
62                 nlmsvc_remove_block(block);
63         bp = &nlm_blocked;
64         if (when != NLM_NEVER) {
65                 if ((when += jiffies) == NLM_NEVER)
66                         when ++;
67                 while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
68                         bp = &b->b_next;
69         } else
70                 while ((b = *bp) != 0)
71                         bp = &b->b_next;
72
73         block->b_queued = 1;
74         block->b_when = when;
75         block->b_next = b;
76         *bp = block;
77 }
78
79 /*
80  * Remove a block from the global list
81  */
82 static int
83 nlmsvc_remove_block(struct nlm_block *block)
84 {
85         struct nlm_block **bp, *b;
86
87         if (!block->b_queued)
88                 return 1;
89         for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
90                 if (b == block) {
91                         *bp = block->b_next;
92                         block->b_queued = 0;
93                         return 1;
94                 }
95         }
96
97         return 0;
98 }
99
100 /*
101  * Find a block for a given lock and optionally remove it from
102  * the list.
103  */
104 static struct nlm_block *
105 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove)
106 {
107         struct nlm_block        **head, *block;
108         struct file_lock        *fl;
109
110         dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
111                                 file, lock->fl.fl_pid,
112                                 (long long)lock->fl.fl_start,
113                                 (long long)lock->fl.fl_end, lock->fl.fl_type);
114         for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
115                 fl = &block->b_call.a_args.lock.fl;
116                 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
117                                 block->b_file, fl->fl_pid,
118                                 (long long)fl->fl_start,
119                                 (long long)fl->fl_end, fl->fl_type,
120                                 nlmdbg_cookie2a(&block->b_call.a_args.cookie));
121                 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
122                         if (remove) {
123                                 *head = block->b_next;
124                                 block->b_queued = 0;
125                         }
126                         return block;
127                 }
128         }
129
130         return NULL;
131 }
132
133 static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
134 {
135         if(a->len != b->len)
136                 return 0;
137         if(memcmp(a->data,b->data,a->len))
138                 return 0;
139         return 1;
140 }
141
142 /*
143  * Find a block with a given NLM cookie.
144  */
145 static inline struct nlm_block *
146 nlmsvc_find_block(struct nlm_cookie *cookie,  struct sockaddr_in *sin)
147 {
148         struct nlm_block *block;
149
150         for (block = nlm_blocked; block; block = block->b_next) {
151                 dprintk("cookie: head of blocked queue %p, block %p\n", 
152                         nlm_blocked, block);
153                 if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie)
154                                 && nlm_cmp_addr(sin, &block->b_host->h_addr))
155                         break;
156         }
157
158         return block;
159 }
160
161 /*
162  * Create a block and initialize it.
163  *
164  * Note: we explicitly set the cookie of the grant reply to that of
165  * the blocked lock request. The spec explicitly mentions that the client
166  * should _not_ rely on the callback containing the same cookie as the
167  * request, but (as I found out later) that's because some implementations
168  * do just this. Never mind the standards comittees, they support our
169  * logging industries.
170  */
171 static inline struct nlm_block *
172 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
173                                 struct nlm_lock *lock, struct nlm_cookie *cookie)
174 {
175         struct nlm_block        *block;
176         struct nlm_host         *host;
177         struct nlm_rqst         *call;
178
179         /* Create host handle for callback */
180         host = nlmclnt_lookup_host(&rqstp->rq_addr,
181                                 rqstp->rq_prot, rqstp->rq_vers);
182         if (host == NULL)
183                 return NULL;
184
185         /* Allocate memory for block, and initialize arguments */
186         if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL)))
187                 goto failed;
188         memset(block, 0, sizeof(*block));
189         locks_init_lock(&block->b_call.a_args.lock.fl);
190         locks_init_lock(&block->b_call.a_res.lock.fl);
191
192         if (!nlmclnt_setgrantargs(&block->b_call, lock))
193                 goto failed_free;
194
195         /* Set notifier function for VFS, and init args */
196         block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
197         block->b_call.a_args.cookie = *cookie;  /* see above */
198
199         dprintk("lockd: created block %p...\n", block);
200
201         /* Create and initialize the block */
202         block->b_daemon = rqstp->rq_server;
203         block->b_host   = host;
204         block->b_file   = file;
205
206         /* Add to file's list of blocks */
207         block->b_fnext  = file->f_blocks;
208         file->f_blocks  = block;
209
210         /* Set up RPC arguments for callback */
211         call = &block->b_call;
212         call->a_host    = host;
213         call->a_flags   = RPC_TASK_ASYNC;
214
215         return block;
216
217 failed_free:
218         kfree(block);
219 failed:
220         nlm_release_host(host);
221         return NULL;
222 }
223
224 /*
225  * Delete a block. If the lock was cancelled or the grant callback
226  * failed, unlock is set to 1.
227  * It is the caller's responsibility to check whether the file
228  * can be closed hereafter.
229  */
230 static void
231 nlmsvc_delete_block(struct nlm_block *block, int unlock)
232 {
233         struct file_lock        *fl = &block->b_call.a_args.lock.fl;
234         struct nlm_file         *file = block->b_file;
235         struct nlm_block        **bp;
236
237         dprintk("lockd: deleting block %p...\n", block);
238
239         /* Remove block from list */
240         nlmsvc_remove_block(block);
241         if (fl->fl_next)
242                 posix_unblock_lock(file->f_file, fl);
243         if (unlock) {
244                 fl->fl_type = F_UNLCK;
245                 posix_lock_file(file->f_file, fl);
246                 block->b_granted = 0;
247         }
248
249         /* If the block is in the middle of a GRANT callback,
250          * don't kill it yet. */
251         if (block->b_incall) {
252                 nlmsvc_insert_block(block, NLM_NEVER);
253                 block->b_done = 1;
254                 return;
255         }
256
257         /* Remove block from file's list of blocks */
258         for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
259                 if (*bp == block) {
260                         *bp = block->b_fnext;
261                         break;
262                 }
263         }
264
265         if (block->b_host)
266                 nlm_release_host(block->b_host);
267         nlmclnt_freegrantargs(&block->b_call);
268         kfree(block);
269 }
270
271 /*
272  * Loop over all blocks and perform the action specified.
273  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
274  */
275 int
276 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
277 {
278         struct nlm_block        *block, *next;
279
280         down(&file->f_sema);
281         for (block = file->f_blocks; block; block = next) {
282                 next = block->b_fnext;
283                 if (action == NLM_ACT_MARK)
284                         block->b_host->h_inuse = 1;
285                 else if (action == NLM_ACT_UNLOCK) {
286                         if (host == NULL || host == block->b_host)
287                                 nlmsvc_delete_block(block, 1);
288                 }
289         }
290         up(&file->f_sema);
291         return 0;
292 }
293
294 /*
295  * Attempt to establish a lock, and if it can't be granted, block it
296  * if required.
297  */
298 u32
299 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
300                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
301 {
302         struct file_lock        *conflock;
303         struct nlm_block        *block;
304         int                     error;
305
306         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
307                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
308                                 file->f_file->f_dentry->d_inode->i_ino,
309                                 lock->fl.fl_type, lock->fl.fl_pid,
310                                 (long long)lock->fl.fl_start,
311                                 (long long)lock->fl.fl_end,
312                                 wait);
313
314
315         /* Get existing block (in case client is busy-waiting) */
316         block = nlmsvc_lookup_block(file, lock, 0);
317
318         lock->fl.fl_flags |= FL_LOCKD;
319
320 again:
321         /* Lock file against concurrent access */
322         down(&file->f_sema);
323
324         if (!(conflock = posix_test_lock(file->f_file, &lock->fl))) {
325                 error = posix_lock_file(file->f_file, &lock->fl);
326
327                 if (block)
328                         nlmsvc_delete_block(block, 0);
329                 up(&file->f_sema);
330
331                 dprintk("lockd: posix_lock_file returned %d\n", -error);
332                 switch(-error) {
333                 case 0:
334                         return nlm_granted;
335                 case EDEADLK:
336                         return nlm_deadlock;
337                 case EAGAIN:
338                         return nlm_lck_denied;
339                 default:                        /* includes ENOLCK */
340                         return nlm_lck_denied_nolocks;
341                 }
342         }
343
344         if (!wait) {
345                 up(&file->f_sema);
346                 return nlm_lck_denied;
347         }
348
349         if (posix_locks_deadlock(&lock->fl, conflock)) {
350                 up(&file->f_sema);
351                 return nlm_deadlock;
352         }
353
354         /* If we don't have a block, create and initialize it. Then
355          * retry because we may have slept in kmalloc. */
356         /* We have to release f_sema as nlmsvc_create_block may try to
357          * to claim it while doing host garbage collection */
358         if (block == NULL) {
359                 up(&file->f_sema);
360                 dprintk("lockd: blocking on this lock (allocating).\n");
361                 if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie)))
362                         return nlm_lck_denied_nolocks;
363                 goto again;
364         }
365
366         /* Append to list of blocked */
367         nlmsvc_insert_block(block, NLM_NEVER);
368
369         if (list_empty(&block->b_call.a_args.lock.fl.fl_block)) {
370                 /* Now add block to block list of the conflicting lock
371                    if we haven't done so. */
372                 dprintk("lockd: blocking on this lock.\n");
373                 posix_block_lock(conflock, &block->b_call.a_args.lock.fl);
374         }
375
376         up(&file->f_sema);
377         return nlm_lck_blocked;
378 }
379
380 /*
381  * Test for presence of a conflicting lock.
382  */
383 u32
384 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
385                                        struct nlm_lock *conflock)
386 {
387         struct file_lock        *fl;
388
389         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
390                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
391                                 file->f_file->f_dentry->d_inode->i_ino,
392                                 lock->fl.fl_type,
393                                 (long long)lock->fl.fl_start,
394                                 (long long)lock->fl.fl_end);
395
396         if ((fl = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
397                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
398                                 fl->fl_type, (long long)fl->fl_start,
399                                 (long long)fl->fl_end);
400                 conflock->caller = "somehost";  /* FIXME */
401                 conflock->oh.len = 0;           /* don't return OH info */
402                 conflock->fl = *fl;
403                 return nlm_lck_denied;
404         }
405
406         return nlm_granted;
407 }
408
409 /*
410  * Remove a lock.
411  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
412  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
413  * afterwards. In this case the block will still be there, and hence
414  * must be removed.
415  */
416 u32
417 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
418 {
419         int     error;
420
421         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
422                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
423                                 file->f_file->f_dentry->d_inode->i_ino,
424                                 lock->fl.fl_pid,
425                                 (long long)lock->fl.fl_start,
426                                 (long long)lock->fl.fl_end);
427
428         /* First, cancel any lock that might be there */
429         nlmsvc_cancel_blocked(file, lock);
430
431         lock->fl.fl_type = F_UNLCK;
432         error = posix_lock_file(file->f_file, &lock->fl);
433
434         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
435 }
436
437 /*
438  * Cancel a previously blocked request.
439  *
440  * A cancel request always overrides any grant that may currently
441  * be in progress.
442  * The calling procedure must check whether the file can be closed.
443  */
444 u32
445 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
446 {
447         struct nlm_block        *block;
448
449         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
450                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
451                                 file->f_file->f_dentry->d_inode->i_ino,
452                                 lock->fl.fl_pid,
453                                 (long long)lock->fl.fl_start,
454                                 (long long)lock->fl.fl_end);
455
456         down(&file->f_sema);
457         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
458                 nlmsvc_delete_block(block, 1);
459         up(&file->f_sema);
460         return nlm_granted;
461 }
462
463 /*
464  * Unblock a blocked lock request. This is a callback invoked from the
465  * VFS layer when a lock on which we blocked is removed.
466  *
467  * This function doesn't grant the blocked lock instantly, but rather moves
468  * the block to the head of nlm_blocked where it can be picked up by lockd.
469  */
470 static void
471 nlmsvc_notify_blocked(struct file_lock *fl)
472 {
473         struct nlm_block        **bp, *block;
474
475         dprintk("lockd: VFS unblock notification for block %p\n", fl);
476         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
477                 if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
478                         nlmsvc_insert_block(block, 0);
479                         svc_wake_up(block->b_daemon);
480                         return;
481                 }
482         }
483
484         printk(KERN_WARNING "lockd: notification for unknown block!\n");
485 }
486
487 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
488 {
489         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
490 }
491
492 struct lock_manager_operations nlmsvc_lock_operations = {
493         .fl_compare_owner = nlmsvc_same_owner,
494         .fl_notify = nlmsvc_notify_blocked,
495 };
496
497 /*
498  * Try to claim a lock that was previously blocked.
499  *
500  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
501  * RPC thread when notifying the client. This seems like overkill...
502  * Here's why:
503  *  -   we don't want to use a synchronous RPC thread, otherwise
504  *      we might find ourselves hanging on a dead portmapper.
505  *  -   Some lockd implementations (e.g. HP) don't react to
506  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
507  */
508 static void
509 nlmsvc_grant_blocked(struct nlm_block *block)
510 {
511         struct nlm_file         *file = block->b_file;
512         struct nlm_lock         *lock = &block->b_call.a_args.lock;
513         struct file_lock        *conflock;
514         int                     error;
515
516         dprintk("lockd: grant blocked lock %p\n", block);
517
518         /* First thing is lock the file */
519         down(&file->f_sema);
520
521         /* Unlink block request from list */
522         nlmsvc_remove_block(block);
523
524         /* If b_granted is true this means we've been here before.
525          * Just retry the grant callback, possibly refreshing the RPC
526          * binding */
527         if (block->b_granted) {
528                 nlm_rebind_host(block->b_host);
529                 goto callback;
530         }
531
532         /* Try the lock operation again */
533         if ((conflock = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
534                 /* Bummer, we blocked again */
535                 dprintk("lockd: lock still blocked\n");
536                 nlmsvc_insert_block(block, NLM_NEVER);
537                 posix_block_lock(conflock, &lock->fl);
538                 up(&file->f_sema);
539                 return;
540         }
541
542         /* Alright, no conflicting lock. Now lock it for real. If the
543          * following yields an error, this is most probably due to low
544          * memory. Retry the lock in a few seconds.
545          */
546         if ((error = posix_lock_file(file->f_file, &lock->fl)) < 0) {
547                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
548                                 -error, __FUNCTION__);
549                 nlmsvc_insert_block(block, 10 * HZ);
550                 up(&file->f_sema);
551                 return;
552         }
553
554 callback:
555         /* Lock was granted by VFS. */
556         dprintk("lockd: GRANTing blocked lock.\n");
557         block->b_granted = 1;
558         block->b_incall  = 1;
559
560         /* Schedule next grant callback in 30 seconds */
561         nlmsvc_insert_block(block, 30 * HZ);
562
563         /* Call the client */
564         nlm_get_host(block->b_call.a_host);
565         if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
566                                                 &nlmsvc_grant_ops) < 0)
567                 nlm_release_host(block->b_call.a_host);
568         up(&file->f_sema);
569 }
570
571 /*
572  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
573  * RPC call has succeeded or timed out.
574  * Like all RPC callbacks, it is invoked by the rpciod process, so it
575  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
576  * chain once more in order to have it removed by lockd itself (which can
577  * then sleep on the file semaphore without disrupting e.g. the nfs client).
578  */
579 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
580 {
581         struct nlm_rqst         *call = data;
582         struct nlm_block        *block;
583         unsigned long           timeout;
584         struct sockaddr_in      *peer_addr = RPC_PEERADDR(task->tk_client);
585
586         dprintk("lockd: GRANT_MSG RPC callback\n");
587         dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
588                 nlmdbg_cookie2a(&call->a_args.cookie),
589                 NIPQUAD(peer_addr->sin_addr.s_addr));
590         if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
591                 dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
592                         nlmdbg_cookie2a(&call->a_args.cookie),
593                         NIPQUAD(peer_addr->sin_addr.s_addr));
594                 return;
595         }
596
597         /* Technically, we should down the file semaphore here. Since we
598          * move the block towards the head of the queue only, no harm
599          * can be done, though. */
600         if (task->tk_status < 0) {
601                 /* RPC error: Re-insert for retransmission */
602                 timeout = 10 * HZ;
603         } else if (block->b_done) {
604                 /* Block already removed, kill it for real */
605                 timeout = 0;
606         } else {
607                 /* Call was successful, now wait for client callback */
608                 timeout = 60 * HZ;
609         }
610         nlmsvc_insert_block(block, timeout);
611         svc_wake_up(block->b_daemon);
612         block->b_incall = 0;
613
614         nlm_release_host(call->a_host);
615 }
616
617 static const struct rpc_call_ops nlmsvc_grant_ops = {
618         .rpc_call_done = nlmsvc_grant_callback,
619 };
620
621 /*
622  * We received a GRANT_RES callback. Try to find the corresponding
623  * block.
624  */
625 void
626 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
627 {
628         struct nlm_block        *block;
629         struct nlm_file         *file;
630
631         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", 
632                 *(unsigned int *)(cookie->data), 
633                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
634         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
635                 return;
636         file = block->b_file;
637
638         file->f_count++;
639         down(&file->f_sema);
640         if ((block = nlmsvc_find_block(cookie,&rqstp->rq_addr)) != NULL) {
641                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
642                         /* Try again in a couple of seconds */
643                         nlmsvc_insert_block(block, 10 * HZ);
644                         block = NULL;
645                 } else {
646                         /* Lock is now held by client, or has been rejected.
647                          * In both cases, the block should be removed. */
648                         up(&file->f_sema);
649                         if (status == NLM_LCK_GRANTED)
650                                 nlmsvc_delete_block(block, 0);
651                         else
652                                 nlmsvc_delete_block(block, 1);
653                 }
654         }
655         if (!block)
656                 up(&file->f_sema);
657         nlm_release_file(file);
658 }
659
660 /*
661  * Retry all blocked locks that have been notified. This is where lockd
662  * picks up locks that can be granted, or grant notifications that must
663  * be retransmitted.
664  */
665 unsigned long
666 nlmsvc_retry_blocked(void)
667 {
668         struct nlm_block        *block;
669
670         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
671                         nlm_blocked,
672                         nlm_blocked? nlm_blocked->b_when : 0);
673         while ((block = nlm_blocked) != 0) {
674                 if (block->b_when == NLM_NEVER)
675                         break;
676                 if (time_after(block->b_when,jiffies))
677                         break;
678                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
679                         block, block->b_when, block->b_done);
680                 if (block->b_done)
681                         nlmsvc_delete_block(block, 0);
682                 else
683                         nlmsvc_grant_blocked(block);
684         }
685
686         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
687                 return (block->b_when - jiffies);
688
689         return MAX_SCHEDULE_TIMEOUT;
690 }