1d3a74df93f39757f02df01e9d974f1b9cddf107
[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_flags |= FL_SLEEP;
197         block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
198         block->b_call.a_args.cookie = *cookie;  /* see above */
199
200         dprintk("lockd: created block %p...\n", block);
201
202         /* Create and initialize the block */
203         block->b_daemon = rqstp->rq_server;
204         block->b_host   = host;
205         block->b_file   = file;
206
207         /* Add to file's list of blocks */
208         block->b_fnext  = file->f_blocks;
209         file->f_blocks  = block;
210
211         /* Set up RPC arguments for callback */
212         call = &block->b_call;
213         call->a_host    = host;
214         call->a_flags   = RPC_TASK_ASYNC;
215
216         return block;
217
218 failed_free:
219         kfree(block);
220 failed:
221         nlm_release_host(host);
222         return NULL;
223 }
224
225 /*
226  * Delete a block. If the lock was cancelled or the grant callback
227  * failed, unlock is set to 1.
228  * It is the caller's responsibility to check whether the file
229  * can be closed hereafter.
230  */
231 static int
232 nlmsvc_delete_block(struct nlm_block *block)
233 {
234         struct file_lock        *fl = &block->b_call.a_args.lock.fl;
235         struct nlm_file         *file = block->b_file;
236         struct nlm_block        **bp;
237         int status;
238
239         dprintk("lockd: deleting block %p...\n", block);
240
241         /* Remove block from list */
242         nlmsvc_remove_block(block);
243         status = posix_unblock_lock(file->f_file, fl);
244
245         /* If the block is in the middle of a GRANT callback,
246          * don't kill it yet. */
247         if (block->b_incall) {
248                 nlmsvc_insert_block(block, NLM_NEVER);
249                 block->b_done = 1;
250                 return status;
251         }
252
253         /* Remove block from file's list of blocks */
254         for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
255                 if (*bp == block) {
256                         *bp = block->b_fnext;
257                         break;
258                 }
259         }
260
261         if (block->b_host)
262                 nlm_release_host(block->b_host);
263         nlmclnt_freegrantargs(&block->b_call);
264         kfree(block);
265         return status;
266 }
267
268 /*
269  * Loop over all blocks and perform the action specified.
270  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
271  */
272 int
273 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
274 {
275         struct nlm_block        *block, *next;
276         /* XXX: Will everything get cleaned up if we don't unlock here? */
277
278         down(&file->f_sema);
279         for (block = file->f_blocks; block; block = next) {
280                 next = block->b_fnext;
281                 if (action == NLM_ACT_MARK)
282                         block->b_host->h_inuse = 1;
283                 else if (action == NLM_ACT_UNLOCK) {
284                         if (host == NULL || host == block->b_host)
285                                 nlmsvc_delete_block(block);
286                 }
287         }
288         up(&file->f_sema);
289         return 0;
290 }
291
292 /*
293  * Attempt to establish a lock, and if it can't be granted, block it
294  * if required.
295  */
296 u32
297 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
298                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
299 {
300         struct nlm_block        *block, *newblock = NULL;
301         int                     error;
302         u32                     ret;
303
304         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
305                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
306                                 file->f_file->f_dentry->d_inode->i_ino,
307                                 lock->fl.fl_type, lock->fl.fl_pid,
308                                 (long long)lock->fl.fl_start,
309                                 (long long)lock->fl.fl_end,
310                                 wait);
311
312
313         lock->fl.fl_flags &= ~FL_SLEEP;
314 again:
315         /* Lock file against concurrent access */
316         down(&file->f_sema);
317         /* Get existing block (in case client is busy-waiting) */
318         block = nlmsvc_lookup_block(file, lock, 0);
319         if (block == NULL) {
320                 if (newblock != NULL)
321                         lock = &newblock->b_call.a_args.lock.fl;
322         } else
323                 lock = &block->b_call.a_args.lock.fl;
324
325         error = posix_lock_file(file->f_file, &lock->fl);
326         lock->fl.fl_flags &= ~FL_SLEEP;
327
328         dprintk("lockd: posix_lock_file returned %d\n", error);
329
330         switch(error) {
331                 case 0:
332                         ret = nlm_granted;
333                         goto out;
334                 case -EAGAIN:
335                         break;
336                 case -EDEADLK:
337                         ret = nlm_deadlock;
338                         goto out;
339                 default:                        /* includes ENOLCK */
340                         ret = nlm_lck_denied_nolocks;
341                         goto out;
342         }
343
344         ret = nlm_lck_denied;
345         if (!wait)
346                 goto out;
347
348         ret = nlm_lck_blocked;
349         if (block != NULL)
350                 goto out;
351
352         /* If we don't have a block, create and initialize it. Then
353          * retry because we may have slept in kmalloc. */
354         /* We have to release f_sema as nlmsvc_create_block may try to
355          * to claim it while doing host garbage collection */
356         if (newblock == NULL) {
357                 up(&file->f_sema);
358                 dprintk("lockd: blocking on this lock (allocating).\n");
359                 if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
360                         return nlm_lck_denied_nolocks;
361                 goto again;
362         }
363
364         /* Append to list of blocked */
365         nlmsvc_insert_block(newblock, NLM_NEVER);
366         newblock = NULL;
367
368 out:
369         up(&file->f_sema);
370         if (newblock != NULL)
371                 nlmsvc_delete_block(newblock);
372         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
373         return ret;
374 }
375
376 /*
377  * Test for presence of a conflicting lock.
378  */
379 u32
380 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
381                                        struct nlm_lock *conflock)
382 {
383         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
384                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
385                                 file->f_file->f_dentry->d_inode->i_ino,
386                                 lock->fl.fl_type,
387                                 (long long)lock->fl.fl_start,
388                                 (long long)lock->fl.fl_end);
389
390         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
391                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
392                                 conflock->fl.fl_type,
393                                 (long long)conflock->fl.fl_start,
394                                 (long long)conflock->fl.fl_end);
395                 conflock->caller = "somehost";  /* FIXME */
396                 conflock->oh.len = 0;           /* don't return OH info */
397                 conflock->svid = conflock->fl.fl_pid;
398                 return nlm_lck_denied;
399         }
400
401         return nlm_granted;
402 }
403
404 /*
405  * Remove a lock.
406  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
407  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
408  * afterwards. In this case the block will still be there, and hence
409  * must be removed.
410  */
411 u32
412 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
413 {
414         int     error;
415
416         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
417                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
418                                 file->f_file->f_dentry->d_inode->i_ino,
419                                 lock->fl.fl_pid,
420                                 (long long)lock->fl.fl_start,
421                                 (long long)lock->fl.fl_end);
422
423         /* First, cancel any lock that might be there */
424         nlmsvc_cancel_blocked(file, lock);
425
426         lock->fl.fl_type = F_UNLCK;
427         error = posix_lock_file(file->f_file, &lock->fl);
428
429         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
430 }
431
432 /*
433  * Cancel a previously blocked request.
434  *
435  * A cancel request always overrides any grant that may currently
436  * be in progress.
437  * The calling procedure must check whether the file can be closed.
438  */
439 u32
440 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
441 {
442         struct nlm_block        *block;
443         int status = 0;
444
445         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
446                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
447                                 file->f_file->f_dentry->d_inode->i_ino,
448                                 lock->fl.fl_pid,
449                                 (long long)lock->fl.fl_start,
450                                 (long long)lock->fl.fl_end);
451
452         down(&file->f_sema);
453         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
454                 status = nlmsvc_delete_block(block);
455         up(&file->f_sema);
456         return status ? nlm_lck_denied : nlm_granted;
457 }
458
459 /*
460  * Unblock a blocked lock request. This is a callback invoked from the
461  * VFS layer when a lock on which we blocked is removed.
462  *
463  * This function doesn't grant the blocked lock instantly, but rather moves
464  * the block to the head of nlm_blocked where it can be picked up by lockd.
465  */
466 static void
467 nlmsvc_notify_blocked(struct file_lock *fl)
468 {
469         struct nlm_block        **bp, *block;
470
471         dprintk("lockd: VFS unblock notification for block %p\n", fl);
472         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
473                 if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
474                         nlmsvc_insert_block(block, 0);
475                         svc_wake_up(block->b_daemon);
476                         return;
477                 }
478         }
479
480         printk(KERN_WARNING "lockd: notification for unknown block!\n");
481 }
482
483 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
484 {
485         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
486 }
487
488 struct lock_manager_operations nlmsvc_lock_operations = {
489         .fl_compare_owner = nlmsvc_same_owner,
490         .fl_notify = nlmsvc_notify_blocked,
491 };
492
493 /*
494  * Try to claim a lock that was previously blocked.
495  *
496  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
497  * RPC thread when notifying the client. This seems like overkill...
498  * Here's why:
499  *  -   we don't want to use a synchronous RPC thread, otherwise
500  *      we might find ourselves hanging on a dead portmapper.
501  *  -   Some lockd implementations (e.g. HP) don't react to
502  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
503  */
504 static void
505 nlmsvc_grant_blocked(struct nlm_block *block)
506 {
507         struct nlm_file         *file = block->b_file;
508         struct nlm_lock         *lock = &block->b_call.a_args.lock;
509         int                     error;
510
511         dprintk("lockd: grant blocked lock %p\n", block);
512
513         /* First thing is lock the file */
514         down(&file->f_sema);
515
516         /* Unlink block request from list */
517         nlmsvc_remove_block(block);
518
519         /* If b_granted is true this means we've been here before.
520          * Just retry the grant callback, possibly refreshing the RPC
521          * binding */
522         if (block->b_granted) {
523                 nlm_rebind_host(block->b_host);
524                 goto callback;
525         }
526
527         /* Try the lock operation again */
528         posix_unblock_lock(file->f_file, &lock->fl);
529         lock->fl.fl_flags |= FL_SLEEP;
530         error = posix_lock_file(file->f_file, &lock->fl);
531         lock->fl.fl_flags &= ~FL_SLEEP;
532
533         switch (error) {
534         case 0:
535                 break;
536         case -EAGAIN:
537                 dprintk("lockd: lock still blocked\n");
538                 nlmsvc_insert_block(block, NLM_NEVER);
539                 goto out_unlock;
540         default:
541                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
542                                 -error, __FUNCTION__);
543                 nlmsvc_insert_block(block, 10 * HZ);
544                 goto out_unlock;
545         }
546
547 callback:
548         /* Lock was granted by VFS. */
549         dprintk("lockd: GRANTing blocked lock.\n");
550         block->b_granted = 1;
551         block->b_incall  = 1;
552
553         /* Schedule next grant callback in 30 seconds */
554         nlmsvc_insert_block(block, 30 * HZ);
555
556         /* Call the client */
557         nlm_get_host(block->b_call.a_host);
558         if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
559                                                 &nlmsvc_grant_ops) < 0)
560                 nlm_release_host(block->b_call.a_host);
561 out_unlock:
562         up(&file->f_sema);
563 }
564
565 /*
566  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
567  * RPC call has succeeded or timed out.
568  * Like all RPC callbacks, it is invoked by the rpciod process, so it
569  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
570  * chain once more in order to have it removed by lockd itself (which can
571  * then sleep on the file semaphore without disrupting e.g. the nfs client).
572  */
573 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
574 {
575         struct nlm_rqst         *call = data;
576         struct nlm_block        *block;
577         unsigned long           timeout;
578         struct sockaddr_in      *peer_addr = RPC_PEERADDR(task->tk_client);
579
580         dprintk("lockd: GRANT_MSG RPC callback\n");
581         dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
582                 nlmdbg_cookie2a(&call->a_args.cookie),
583                 NIPQUAD(peer_addr->sin_addr.s_addr));
584         if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
585                 dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
586                         nlmdbg_cookie2a(&call->a_args.cookie),
587                         NIPQUAD(peer_addr->sin_addr.s_addr));
588                 return;
589         }
590
591         /* Technically, we should down the file semaphore here. Since we
592          * move the block towards the head of the queue only, no harm
593          * can be done, though. */
594         if (task->tk_status < 0) {
595                 /* RPC error: Re-insert for retransmission */
596                 timeout = 10 * HZ;
597         } else if (block->b_done) {
598                 /* Block already removed, kill it for real */
599                 timeout = 0;
600         } else {
601                 /* Call was successful, now wait for client callback */
602                 timeout = 60 * HZ;
603         }
604         nlmsvc_insert_block(block, timeout);
605         svc_wake_up(block->b_daemon);
606         block->b_incall = 0;
607
608         nlm_release_host(call->a_host);
609 }
610
611 static const struct rpc_call_ops nlmsvc_grant_ops = {
612         .rpc_call_done = nlmsvc_grant_callback,
613 };
614
615 /*
616  * We received a GRANT_RES callback. Try to find the corresponding
617  * block.
618  */
619 void
620 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
621 {
622         struct nlm_block        *block;
623         struct nlm_file         *file;
624
625         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", 
626                 *(unsigned int *)(cookie->data), 
627                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
628         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
629                 return;
630         file = block->b_file;
631
632         file->f_count++;
633         down(&file->f_sema);
634         block = nlmsvc_find_block(cookie, &rqstp->rq_addr);
635         if (block) {
636                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
637                         /* Try again in a couple of seconds */
638                         nlmsvc_insert_block(block, 10 * HZ);
639                         up(&file->f_sema);
640                 } else {
641                         /* Lock is now held by client, or has been rejected.
642                          * In both cases, the block should be removed. */
643                         nlmsvc_delete_block(block);
644                         up(&file->f_sema);
645                 }
646         }
647         nlm_release_file(file);
648 }
649
650 /*
651  * Retry all blocked locks that have been notified. This is where lockd
652  * picks up locks that can be granted, or grant notifications that must
653  * be retransmitted.
654  */
655 unsigned long
656 nlmsvc_retry_blocked(void)
657 {
658         struct nlm_block        *block;
659
660         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
661                         nlm_blocked,
662                         nlm_blocked? nlm_blocked->b_when : 0);
663         while ((block = nlm_blocked) != 0) {
664                 if (block->b_when == NLM_NEVER)
665                         break;
666                 if (time_after(block->b_when,jiffies))
667                         break;
668                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
669                         block, block->b_when, block->b_done);
670                 if (block->b_done)
671                         nlmsvc_delete_block(block);
672                 else
673                         nlmsvc_grant_blocked(block);
674         }
675
676         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
677                 return (block->b_when - jiffies);
678
679         return MAX_SCHEDULE_TIMEOUT;
680 }