xref: /openbmc/linux/fs/lockd/svclock.c (revision 87c2ce3b)
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 int
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 	int status = 0;
237 
238 	dprintk("lockd: deleting block %p...\n", block);
239 
240 	/* Remove block from list */
241 	nlmsvc_remove_block(block);
242 	if (unlock)
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, 1);
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 file_lock	*conflock;
301 	struct nlm_block	*block;
302 	int			error;
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 	/* Get existing block (in case client is busy-waiting) */
314 	block = nlmsvc_lookup_block(file, lock, 0);
315 
316 	lock->fl.fl_flags |= FL_LOCKD;
317 
318 again:
319 	/* Lock file against concurrent access */
320 	down(&file->f_sema);
321 
322 	if (!(conflock = posix_test_lock(file->f_file, &lock->fl))) {
323 		error = posix_lock_file(file->f_file, &lock->fl);
324 
325 		if (block)
326 			nlmsvc_delete_block(block, 0);
327 		up(&file->f_sema);
328 
329 		dprintk("lockd: posix_lock_file returned %d\n", -error);
330 		switch(-error) {
331 		case 0:
332 			return nlm_granted;
333 		case EDEADLK:
334 			return nlm_deadlock;
335 		case EAGAIN:
336 			return nlm_lck_denied;
337 		default:			/* includes ENOLCK */
338 			return nlm_lck_denied_nolocks;
339 		}
340 	}
341 
342 	if (!wait) {
343 		up(&file->f_sema);
344 		return nlm_lck_denied;
345 	}
346 
347 	if (posix_locks_deadlock(&lock->fl, conflock)) {
348 		up(&file->f_sema);
349 		return nlm_deadlock;
350 	}
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 (block == NULL) {
357 		up(&file->f_sema);
358 		dprintk("lockd: blocking on this lock (allocating).\n");
359 		if (!(block = 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(block, NLM_NEVER);
366 
367 	if (list_empty(&block->b_call.a_args.lock.fl.fl_block)) {
368 		/* Now add block to block list of the conflicting lock
369 		   if we haven't done so. */
370 		dprintk("lockd: blocking on this lock.\n");
371 		posix_block_lock(conflock, &block->b_call.a_args.lock.fl);
372 	}
373 
374 	up(&file->f_sema);
375 	return nlm_lck_blocked;
376 }
377 
378 /*
379  * Test for presence of a conflicting lock.
380  */
381 u32
382 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
383 				       struct nlm_lock *conflock)
384 {
385 	struct file_lock	*fl;
386 
387 	dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
388 				file->f_file->f_dentry->d_inode->i_sb->s_id,
389 				file->f_file->f_dentry->d_inode->i_ino,
390 				lock->fl.fl_type,
391 				(long long)lock->fl.fl_start,
392 				(long long)lock->fl.fl_end);
393 
394 	if ((fl = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
395 		dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
396 				fl->fl_type, (long long)fl->fl_start,
397 				(long long)fl->fl_end);
398 		conflock->caller = "somehost";	/* FIXME */
399 		conflock->oh.len = 0;		/* don't return OH info */
400 		conflock->fl = *fl;
401 		return nlm_lck_denied;
402 	}
403 
404 	return nlm_granted;
405 }
406 
407 /*
408  * Remove a lock.
409  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
410  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
411  * afterwards. In this case the block will still be there, and hence
412  * must be removed.
413  */
414 u32
415 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
416 {
417 	int	error;
418 
419 	dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
420 				file->f_file->f_dentry->d_inode->i_sb->s_id,
421 				file->f_file->f_dentry->d_inode->i_ino,
422 				lock->fl.fl_pid,
423 				(long long)lock->fl.fl_start,
424 				(long long)lock->fl.fl_end);
425 
426 	/* First, cancel any lock that might be there */
427 	nlmsvc_cancel_blocked(file, lock);
428 
429 	lock->fl.fl_type = F_UNLCK;
430 	error = posix_lock_file(file->f_file, &lock->fl);
431 
432 	return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
433 }
434 
435 /*
436  * Cancel a previously blocked request.
437  *
438  * A cancel request always overrides any grant that may currently
439  * be in progress.
440  * The calling procedure must check whether the file can be closed.
441  */
442 u32
443 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
444 {
445 	struct nlm_block	*block;
446 	int status = 0;
447 
448 	dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
449 				file->f_file->f_dentry->d_inode->i_sb->s_id,
450 				file->f_file->f_dentry->d_inode->i_ino,
451 				lock->fl.fl_pid,
452 				(long long)lock->fl.fl_start,
453 				(long long)lock->fl.fl_end);
454 
455 	down(&file->f_sema);
456 	if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL)
457 		status = nlmsvc_delete_block(block, 1);
458 	up(&file->f_sema);
459 	return status ? nlm_lck_denied : nlm_granted;
460 }
461 
462 /*
463  * Unblock a blocked lock request. This is a callback invoked from the
464  * VFS layer when a lock on which we blocked is removed.
465  *
466  * This function doesn't grant the blocked lock instantly, but rather moves
467  * the block to the head of nlm_blocked where it can be picked up by lockd.
468  */
469 static void
470 nlmsvc_notify_blocked(struct file_lock *fl)
471 {
472 	struct nlm_block	**bp, *block;
473 
474 	dprintk("lockd: VFS unblock notification for block %p\n", fl);
475 	for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
476 		if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
477 			nlmsvc_insert_block(block, 0);
478 			svc_wake_up(block->b_daemon);
479 			return;
480 		}
481 	}
482 
483 	printk(KERN_WARNING "lockd: notification for unknown block!\n");
484 }
485 
486 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
487 {
488 	return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
489 }
490 
491 struct lock_manager_operations nlmsvc_lock_operations = {
492 	.fl_compare_owner = nlmsvc_same_owner,
493 	.fl_notify = nlmsvc_notify_blocked,
494 };
495 
496 /*
497  * Try to claim a lock that was previously blocked.
498  *
499  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
500  * RPC thread when notifying the client. This seems like overkill...
501  * Here's why:
502  *  -	we don't want to use a synchronous RPC thread, otherwise
503  *	we might find ourselves hanging on a dead portmapper.
504  *  -	Some lockd implementations (e.g. HP) don't react to
505  *	RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
506  */
507 static void
508 nlmsvc_grant_blocked(struct nlm_block *block)
509 {
510 	struct nlm_file		*file = block->b_file;
511 	struct nlm_lock		*lock = &block->b_call.a_args.lock;
512 	struct file_lock	*conflock;
513 	int			error;
514 
515 	dprintk("lockd: grant blocked lock %p\n", block);
516 
517 	/* First thing is lock the file */
518 	down(&file->f_sema);
519 
520 	/* Unlink block request from list */
521 	nlmsvc_remove_block(block);
522 
523 	/* If b_granted is true this means we've been here before.
524 	 * Just retry the grant callback, possibly refreshing the RPC
525 	 * binding */
526 	if (block->b_granted) {
527 		nlm_rebind_host(block->b_host);
528 		goto callback;
529 	}
530 
531 	/* Try the lock operation again */
532 	if ((conflock = posix_test_lock(file->f_file, &lock->fl)) != NULL) {
533 		/* Bummer, we blocked again */
534 		dprintk("lockd: lock still blocked\n");
535 		nlmsvc_insert_block(block, NLM_NEVER);
536 		posix_block_lock(conflock, &lock->fl);
537 		up(&file->f_sema);
538 		return;
539 	}
540 
541 	/* Alright, no conflicting lock. Now lock it for real. If the
542 	 * following yields an error, this is most probably due to low
543 	 * memory. Retry the lock in a few seconds.
544 	 */
545 	if ((error = posix_lock_file(file->f_file, &lock->fl)) < 0) {
546 		printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
547 				-error, __FUNCTION__);
548 		nlmsvc_insert_block(block, 10 * HZ);
549 		up(&file->f_sema);
550 		return;
551 	}
552 
553 callback:
554 	/* Lock was granted by VFS. */
555 	dprintk("lockd: GRANTing blocked lock.\n");
556 	block->b_granted = 1;
557 	block->b_incall  = 1;
558 
559 	/* Schedule next grant callback in 30 seconds */
560 	nlmsvc_insert_block(block, 30 * HZ);
561 
562 	/* Call the client */
563 	nlm_get_host(block->b_call.a_host);
564 	if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
565 						&nlmsvc_grant_ops) < 0)
566 		nlm_release_host(block->b_call.a_host);
567 	up(&file->f_sema);
568 }
569 
570 /*
571  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
572  * RPC call has succeeded or timed out.
573  * Like all RPC callbacks, it is invoked by the rpciod process, so it
574  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
575  * chain once more in order to have it removed by lockd itself (which can
576  * then sleep on the file semaphore without disrupting e.g. the nfs client).
577  */
578 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
579 {
580 	struct nlm_rqst		*call = data;
581 	struct nlm_block	*block;
582 	unsigned long		timeout;
583 	struct sockaddr_in	*peer_addr = RPC_PEERADDR(task->tk_client);
584 
585 	dprintk("lockd: GRANT_MSG RPC callback\n");
586 	dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n",
587 		nlmdbg_cookie2a(&call->a_args.cookie),
588 		NIPQUAD(peer_addr->sin_addr.s_addr));
589 	if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) {
590 		dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n",
591 			nlmdbg_cookie2a(&call->a_args.cookie),
592 			NIPQUAD(peer_addr->sin_addr.s_addr));
593 		return;
594 	}
595 
596 	/* Technically, we should down the file semaphore here. Since we
597 	 * move the block towards the head of the queue only, no harm
598 	 * can be done, though. */
599 	if (task->tk_status < 0) {
600 		/* RPC error: Re-insert for retransmission */
601 		timeout = 10 * HZ;
602 	} else if (block->b_done) {
603 		/* Block already removed, kill it for real */
604 		timeout = 0;
605 	} else {
606 		/* Call was successful, now wait for client callback */
607 		timeout = 60 * HZ;
608 	}
609 	nlmsvc_insert_block(block, timeout);
610 	svc_wake_up(block->b_daemon);
611 	block->b_incall = 0;
612 
613 	nlm_release_host(call->a_host);
614 }
615 
616 static const struct rpc_call_ops nlmsvc_grant_ops = {
617 	.rpc_call_done = nlmsvc_grant_callback,
618 };
619 
620 /*
621  * We received a GRANT_RES callback. Try to find the corresponding
622  * block.
623  */
624 void
625 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
626 {
627 	struct nlm_block	*block;
628 	struct nlm_file		*file;
629 
630 	dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n",
631 		*(unsigned int *)(cookie->data),
632 		ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
633 	if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
634 		return;
635 	file = block->b_file;
636 
637 	file->f_count++;
638 	down(&file->f_sema);
639 	block = nlmsvc_find_block(cookie, &rqstp->rq_addr);
640 	if (block) {
641 		if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
642 			/* Try again in a couple of seconds */
643 			nlmsvc_insert_block(block, 10 * HZ);
644 			up(&file->f_sema);
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 	nlm_release_file(file);
656 }
657 
658 /*
659  * Retry all blocked locks that have been notified. This is where lockd
660  * picks up locks that can be granted, or grant notifications that must
661  * be retransmitted.
662  */
663 unsigned long
664 nlmsvc_retry_blocked(void)
665 {
666 	struct nlm_block	*block;
667 
668 	dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
669 			nlm_blocked,
670 			nlm_blocked? nlm_blocked->b_when : 0);
671 	while ((block = nlm_blocked) != 0) {
672 		if (block->b_when == NLM_NEVER)
673 			break;
674 	        if (time_after(block->b_when,jiffies))
675 			break;
676 		dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
677 			block, block->b_when, block->b_done);
678 		if (block->b_done)
679 			nlmsvc_delete_block(block, 0);
680 		else
681 			nlmsvc_grant_blocked(block);
682 	}
683 
684 	if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
685 		return (block->b_when - jiffies);
686 
687 	return MAX_SCHEDULE_TIMEOUT;
688 }
689