3c7dd956d9c1d0c98f81bf51811cb14c6c125c62
[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_release_block(struct nlm_block *block);
43 static void     nlmsvc_insert_block(struct nlm_block *block, unsigned long);
44 static int      nlmsvc_remove_block(struct nlm_block *block);
45
46 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
47 static void nlmsvc_freegrantargs(struct nlm_rqst *call);
48 static const struct rpc_call_ops nlmsvc_grant_ops;
49
50 /*
51  * The list of blocked locks to retry
52  */
53 static struct nlm_block *       nlm_blocked;
54
55 /*
56  * Insert a blocked lock into the global list
57  */
58 static void
59 nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
60 {
61         struct nlm_block **bp, *b;
62
63         dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
64         kref_get(&block->b_count);
65         if (block->b_queued)
66                 nlmsvc_remove_block(block);
67         bp = &nlm_blocked;
68         if (when != NLM_NEVER) {
69                 if ((when += jiffies) == NLM_NEVER)
70                         when ++;
71                 while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
72                         bp = &b->b_next;
73         } else
74                 while ((b = *bp) != 0)
75                         bp = &b->b_next;
76
77         block->b_queued = 1;
78         block->b_when = when;
79         block->b_next = b;
80         *bp = block;
81 }
82
83 /*
84  * Remove a block from the global list
85  */
86 static int
87 nlmsvc_remove_block(struct nlm_block *block)
88 {
89         struct nlm_block **bp, *b;
90
91         if (!block->b_queued)
92                 return 1;
93         for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
94                 if (b == block) {
95                         *bp = block->b_next;
96                         block->b_queued = 0;
97                         nlmsvc_release_block(block);
98                         return 1;
99                 }
100         }
101
102         return 0;
103 }
104
105 /*
106  * Find a block for a given lock and optionally remove it from
107  * the list.
108  */
109 static struct nlm_block *
110 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove)
111 {
112         struct nlm_block        **head, *block;
113         struct file_lock        *fl;
114
115         dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
116                                 file, lock->fl.fl_pid,
117                                 (long long)lock->fl.fl_start,
118                                 (long long)lock->fl.fl_end, lock->fl.fl_type);
119         for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
120                 fl = &block->b_call.a_args.lock.fl;
121                 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
122                                 block->b_file, fl->fl_pid,
123                                 (long long)fl->fl_start,
124                                 (long long)fl->fl_end, fl->fl_type,
125                                 nlmdbg_cookie2a(&block->b_call.a_args.cookie));
126                 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
127                         if (remove) {
128                                 *head = block->b_next;
129                                 block->b_queued = 0;
130                         }
131                         kref_get(&block->b_count);
132                         return block;
133                 }
134         }
135
136         return NULL;
137 }
138
139 static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
140 {
141         if(a->len != b->len)
142                 return 0;
143         if(memcmp(a->data,b->data,a->len))
144                 return 0;
145         return 1;
146 }
147
148 /*
149  * Find a block with a given NLM cookie.
150  */
151 static inline struct nlm_block *
152 nlmsvc_find_block(struct nlm_cookie *cookie,  struct sockaddr_in *sin)
153 {
154         struct nlm_block *block;
155
156         for (block = nlm_blocked; block; block = block->b_next) {
157                 dprintk("cookie: head of blocked queue %p, block %p\n", 
158                         nlm_blocked, block);
159                 if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie)
160                                 && nlm_cmp_addr(sin, &block->b_host->h_addr))
161                         break;
162         }
163
164         if (block != NULL)
165                 kref_get(&block->b_count);
166         return block;
167 }
168
169 /*
170  * Create a block and initialize it.
171  *
172  * Note: we explicitly set the cookie of the grant reply to that of
173  * the blocked lock request. The spec explicitly mentions that the client
174  * should _not_ rely on the callback containing the same cookie as the
175  * request, but (as I found out later) that's because some implementations
176  * do just this. Never mind the standards comittees, they support our
177  * logging industries.
178  */
179 static inline struct nlm_block *
180 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file,
181                                 struct nlm_lock *lock, struct nlm_cookie *cookie)
182 {
183         struct nlm_block        *block;
184         struct nlm_host         *host;
185         struct nlm_rqst         *call;
186
187         /* Create host handle for callback */
188         host = nlmclnt_lookup_host(&rqstp->rq_addr,
189                                 rqstp->rq_prot, rqstp->rq_vers);
190         if (host == NULL)
191                 return NULL;
192
193         /* Allocate memory for block, and initialize arguments */
194         if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL)))
195                 goto failed;
196         memset(block, 0, sizeof(*block));
197         locks_init_lock(&block->b_call.a_args.lock.fl);
198         locks_init_lock(&block->b_call.a_res.lock.fl);
199         kref_init(&block->b_count);
200
201         if (!nlmsvc_setgrantargs(&block->b_call, lock))
202                 goto failed_free;
203
204         /* Set notifier function for VFS, and init args */
205         block->b_call.a_args.lock.fl.fl_flags |= FL_SLEEP;
206         block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
207         block->b_call.a_args.cookie = *cookie;  /* see above */
208
209         dprintk("lockd: created block %p...\n", block);
210
211         /* Create and initialize the block */
212         block->b_daemon = rqstp->rq_server;
213         block->b_host   = host;
214         block->b_file   = file;
215
216         /* Add to file's list of blocks */
217         block->b_fnext  = file->f_blocks;
218         file->f_blocks  = block;
219
220         /* Set up RPC arguments for callback */
221         call = &block->b_call;
222         call->a_host    = host;
223         call->a_flags   = RPC_TASK_ASYNC;
224
225         return block;
226
227 failed_free:
228         kfree(block);
229 failed:
230         nlm_release_host(host);
231         return NULL;
232 }
233
234 /*
235  * Delete a block. If the lock was cancelled or the grant callback
236  * failed, unlock is set to 1.
237  * It is the caller's responsibility to check whether the file
238  * can be closed hereafter.
239  */
240 static int nlmsvc_unlink_block(struct nlm_block *block)
241 {
242         int status;
243         dprintk("lockd: unlinking block %p...\n", block);
244
245         /* Remove block from list */
246         status = posix_unblock_lock(block->b_file->f_file, &block->b_call.a_args.lock.fl);
247         nlmsvc_remove_block(block);
248         return status;
249 }
250
251 static void nlmsvc_free_block(struct kref *kref)
252 {
253         struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
254         struct nlm_file         *file = block->b_file;
255         struct nlm_block        **bp;
256
257         dprintk("lockd: freeing block %p...\n", block);
258
259         /* Remove block from file's list of blocks */
260         for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
261                 if (*bp == block) {
262                         *bp = block->b_fnext;
263                         break;
264                 }
265         }
266
267         if (block->b_host)
268                 nlm_release_host(block->b_host);
269         nlmsvc_freegrantargs(&block->b_call);
270         kfree(block);
271 }
272
273 static void nlmsvc_release_block(struct nlm_block *block)
274 {
275         if (block != NULL)
276                 kref_put(&block->b_count, nlmsvc_free_block);
277 }
278
279 /*
280  * Loop over all blocks and perform the action specified.
281  * (NLM_ACT_CHECK handled by nlmsvc_inspect_file).
282  */
283 int
284 nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action)
285 {
286         struct nlm_block        *block, *next;
287         /* XXX: Will everything get cleaned up if we don't unlock here? */
288
289         down(&file->f_sema);
290         for (block = file->f_blocks; block; block = next) {
291                 next = block->b_fnext;
292                 if (action == NLM_ACT_MARK)
293                         block->b_host->h_inuse = 1;
294                 else if (action == NLM_ACT_UNLOCK) {
295                         if (host == NULL || host == block->b_host)
296                                 nlmsvc_unlink_block(block);
297                 }
298         }
299         up(&file->f_sema);
300         return 0;
301 }
302
303 /*
304  * Initialize arguments for GRANTED call. The nlm_rqst structure
305  * has been cleared already.
306  */
307 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
308 {
309         locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
310         memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
311         call->a_args.lock.caller = system_utsname.nodename;
312         call->a_args.lock.oh.len = lock->oh.len;
313
314         /* set default data area */
315         call->a_args.lock.oh.data = call->a_owner;
316         call->a_args.lock.svid = lock->fl.fl_pid;
317
318         if (lock->oh.len > NLMCLNT_OHSIZE) {
319                 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
320                 if (!data) {
321                         nlmsvc_freegrantargs(call);
322                         return 0;
323                 }
324                 call->a_args.lock.oh.data = (u8 *) data;
325         }
326
327         memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
328         return 1;
329 }
330
331 static void nlmsvc_freegrantargs(struct nlm_rqst *call)
332 {
333         struct file_lock *fl = &call->a_args.lock.fl;
334         /*
335          * Check whether we allocated memory for the owner.
336          */
337         if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
338                 kfree(call->a_args.lock.oh.data);
339         }
340         if (fl->fl_ops && fl->fl_ops->fl_release_private)
341                 fl->fl_ops->fl_release_private(fl);
342         if (fl->fl_lmops && fl->fl_lmops->fl_release_private)
343                 fl->fl_lmops->fl_release_private(fl);
344 }
345
346 /*
347  * Attempt to establish a lock, and if it can't be granted, block it
348  * if required.
349  */
350 u32
351 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
352                         struct nlm_lock *lock, int wait, struct nlm_cookie *cookie)
353 {
354         struct nlm_block        *block, *newblock = NULL;
355         int                     error;
356         u32                     ret;
357
358         dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
359                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
360                                 file->f_file->f_dentry->d_inode->i_ino,
361                                 lock->fl.fl_type, lock->fl.fl_pid,
362                                 (long long)lock->fl.fl_start,
363                                 (long long)lock->fl.fl_end,
364                                 wait);
365
366
367         lock->fl.fl_flags &= ~FL_SLEEP;
368 again:
369         /* Lock file against concurrent access */
370         down(&file->f_sema);
371         /* Get existing block (in case client is busy-waiting) */
372         block = nlmsvc_lookup_block(file, lock, 0);
373         if (block == NULL) {
374                 if (newblock != NULL)
375                         lock = &newblock->b_call.a_args.lock;
376         } else
377                 lock = &block->b_call.a_args.lock;
378
379         error = posix_lock_file(file->f_file, &lock->fl);
380         lock->fl.fl_flags &= ~FL_SLEEP;
381
382         dprintk("lockd: posix_lock_file returned %d\n", error);
383
384         switch(error) {
385                 case 0:
386                         ret = nlm_granted;
387                         goto out;
388                 case -EAGAIN:
389                         break;
390                 case -EDEADLK:
391                         ret = nlm_deadlock;
392                         goto out;
393                 default:                        /* includes ENOLCK */
394                         ret = nlm_lck_denied_nolocks;
395                         goto out;
396         }
397
398         ret = nlm_lck_denied;
399         if (!wait)
400                 goto out;
401
402         ret = nlm_lck_blocked;
403         if (block != NULL)
404                 goto out;
405
406         /* If we don't have a block, create and initialize it. Then
407          * retry because we may have slept in kmalloc. */
408         /* We have to release f_sema as nlmsvc_create_block may try to
409          * to claim it while doing host garbage collection */
410         if (newblock == NULL) {
411                 up(&file->f_sema);
412                 dprintk("lockd: blocking on this lock (allocating).\n");
413                 if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie)))
414                         return nlm_lck_denied_nolocks;
415                 goto again;
416         }
417
418         /* Append to list of blocked */
419         nlmsvc_insert_block(newblock, NLM_NEVER);
420 out:
421         up(&file->f_sema);
422         nlmsvc_release_block(newblock);
423         nlmsvc_release_block(block);
424         dprintk("lockd: nlmsvc_lock returned %u\n", ret);
425         return ret;
426 }
427
428 /*
429  * Test for presence of a conflicting lock.
430  */
431 u32
432 nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock,
433                                        struct nlm_lock *conflock)
434 {
435         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
436                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
437                                 file->f_file->f_dentry->d_inode->i_ino,
438                                 lock->fl.fl_type,
439                                 (long long)lock->fl.fl_start,
440                                 (long long)lock->fl.fl_end);
441
442         if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) {
443                 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
444                                 conflock->fl.fl_type,
445                                 (long long)conflock->fl.fl_start,
446                                 (long long)conflock->fl.fl_end);
447                 conflock->caller = "somehost";  /* FIXME */
448                 conflock->oh.len = 0;           /* don't return OH info */
449                 conflock->svid = conflock->fl.fl_pid;
450                 return nlm_lck_denied;
451         }
452
453         return nlm_granted;
454 }
455
456 /*
457  * Remove a lock.
458  * This implies a CANCEL call: We send a GRANT_MSG, the client replies
459  * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
460  * afterwards. In this case the block will still be there, and hence
461  * must be removed.
462  */
463 u32
464 nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
465 {
466         int     error;
467
468         dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
469                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
470                                 file->f_file->f_dentry->d_inode->i_ino,
471                                 lock->fl.fl_pid,
472                                 (long long)lock->fl.fl_start,
473                                 (long long)lock->fl.fl_end);
474
475         /* First, cancel any lock that might be there */
476         nlmsvc_cancel_blocked(file, lock);
477
478         lock->fl.fl_type = F_UNLCK;
479         error = posix_lock_file(file->f_file, &lock->fl);
480
481         return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
482 }
483
484 /*
485  * Cancel a previously blocked request.
486  *
487  * A cancel request always overrides any grant that may currently
488  * be in progress.
489  * The calling procedure must check whether the file can be closed.
490  */
491 u32
492 nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
493 {
494         struct nlm_block        *block;
495         int status = 0;
496
497         dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
498                                 file->f_file->f_dentry->d_inode->i_sb->s_id,
499                                 file->f_file->f_dentry->d_inode->i_ino,
500                                 lock->fl.fl_pid,
501                                 (long long)lock->fl.fl_start,
502                                 (long long)lock->fl.fl_end);
503
504         down(&file->f_sema);
505         if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) {
506                 status = nlmsvc_unlink_block(block);
507                 nlmsvc_release_block(block);
508         }
509         up(&file->f_sema);
510         return status ? nlm_lck_denied : nlm_granted;
511 }
512
513 /*
514  * Unblock a blocked lock request. This is a callback invoked from the
515  * VFS layer when a lock on which we blocked is removed.
516  *
517  * This function doesn't grant the blocked lock instantly, but rather moves
518  * the block to the head of nlm_blocked where it can be picked up by lockd.
519  */
520 static void
521 nlmsvc_notify_blocked(struct file_lock *fl)
522 {
523         struct nlm_block        **bp, *block;
524
525         dprintk("lockd: VFS unblock notification for block %p\n", fl);
526         for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
527                 if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) {
528                         nlmsvc_insert_block(block, 0);
529                         svc_wake_up(block->b_daemon);
530                         return;
531                 }
532         }
533
534         printk(KERN_WARNING "lockd: notification for unknown block!\n");
535 }
536
537 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
538 {
539         return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
540 }
541
542 struct lock_manager_operations nlmsvc_lock_operations = {
543         .fl_compare_owner = nlmsvc_same_owner,
544         .fl_notify = nlmsvc_notify_blocked,
545 };
546
547 /*
548  * Try to claim a lock that was previously blocked.
549  *
550  * Note that we use both the RPC_GRANTED_MSG call _and_ an async
551  * RPC thread when notifying the client. This seems like overkill...
552  * Here's why:
553  *  -   we don't want to use a synchronous RPC thread, otherwise
554  *      we might find ourselves hanging on a dead portmapper.
555  *  -   Some lockd implementations (e.g. HP) don't react to
556  *      RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
557  */
558 static void
559 nlmsvc_grant_blocked(struct nlm_block *block)
560 {
561         struct nlm_file         *file = block->b_file;
562         struct nlm_lock         *lock = &block->b_call.a_args.lock;
563         int                     error;
564
565         dprintk("lockd: grant blocked lock %p\n", block);
566
567         /* First thing is lock the file */
568         down(&file->f_sema);
569
570         /* Unlink block request from list */
571         nlmsvc_unlink_block(block);
572
573         /* If b_granted is true this means we've been here before.
574          * Just retry the grant callback, possibly refreshing the RPC
575          * binding */
576         if (block->b_granted) {
577                 nlm_rebind_host(block->b_host);
578                 goto callback;
579         }
580
581         /* Try the lock operation again */
582         lock->fl.fl_flags |= FL_SLEEP;
583         error = posix_lock_file(file->f_file, &lock->fl);
584         lock->fl.fl_flags &= ~FL_SLEEP;
585
586         switch (error) {
587         case 0:
588                 break;
589         case -EAGAIN:
590                 dprintk("lockd: lock still blocked\n");
591                 nlmsvc_insert_block(block, NLM_NEVER);
592                 goto out_unlock;
593         default:
594                 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
595                                 -error, __FUNCTION__);
596                 nlmsvc_insert_block(block, 10 * HZ);
597                 goto out_unlock;
598         }
599
600 callback:
601         /* Lock was granted by VFS. */
602         dprintk("lockd: GRANTing blocked lock.\n");
603         block->b_granted = 1;
604
605         /* Schedule next grant callback in 30 seconds */
606         nlmsvc_insert_block(block, 30 * HZ);
607
608         /* Call the client */
609         kref_get(&block->b_count);
610         if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG,
611                                                 &nlmsvc_grant_ops) < 0)
612                 nlmsvc_release_block(block);
613 out_unlock:
614         up(&file->f_sema);
615 }
616
617 /*
618  * This is the callback from the RPC layer when the NLM_GRANTED_MSG
619  * RPC call has succeeded or timed out.
620  * Like all RPC callbacks, it is invoked by the rpciod process, so it
621  * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
622  * chain once more in order to have it removed by lockd itself (which can
623  * then sleep on the file semaphore without disrupting e.g. the nfs client).
624  */
625 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
626 {
627         struct nlm_rqst         *call = data;
628         struct nlm_block        *block = container_of(call, struct nlm_block, b_call);
629         unsigned long           timeout;
630
631         dprintk("lockd: GRANT_MSG RPC callback\n");
632
633         /* Technically, we should down the file semaphore here. Since we
634          * move the block towards the head of the queue only, no harm
635          * can be done, though. */
636         if (task->tk_status < 0) {
637                 /* RPC error: Re-insert for retransmission */
638                 timeout = 10 * HZ;
639         } else if (block->b_done) {
640                 /* Block already removed, kill it for real */
641                 timeout = 0;
642         } else {
643                 /* Call was successful, now wait for client callback */
644                 timeout = 60 * HZ;
645         }
646         nlmsvc_insert_block(block, timeout);
647         svc_wake_up(block->b_daemon);
648 }
649
650 void nlmsvc_grant_release(void *data)
651 {
652         nlmsvc_release_block(data);
653 }
654
655 static const struct rpc_call_ops nlmsvc_grant_ops = {
656         .rpc_call_done = nlmsvc_grant_callback,
657         .rpc_release = nlmsvc_grant_release,
658 };
659
660 /*
661  * We received a GRANT_RES callback. Try to find the corresponding
662  * block.
663  */
664 void
665 nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status)
666 {
667         struct nlm_block        *block;
668         struct nlm_file         *file;
669
670         dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", 
671                 *(unsigned int *)(cookie->data), 
672                 ntohl(rqstp->rq_addr.sin_addr.s_addr), status);
673         if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr)))
674                 return;
675         file = block->b_file;
676
677         file->f_count++;
678         down(&file->f_sema);
679         if (block) {
680                 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
681                         /* Try again in a couple of seconds */
682                         nlmsvc_insert_block(block, 10 * HZ);
683                 } else {
684                         /* Lock is now held by client, or has been rejected.
685                          * In both cases, the block should be removed. */
686                         nlmsvc_unlink_block(block);
687                 }
688         }
689         up(&file->f_sema);
690         nlm_release_file(file);
691         nlmsvc_release_block(block);
692 }
693
694 /*
695  * Retry all blocked locks that have been notified. This is where lockd
696  * picks up locks that can be granted, or grant notifications that must
697  * be retransmitted.
698  */
699 unsigned long
700 nlmsvc_retry_blocked(void)
701 {
702         struct nlm_block        *block;
703
704         dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
705                         nlm_blocked,
706                         nlm_blocked? nlm_blocked->b_when : 0);
707         while ((block = nlm_blocked) != 0) {
708                 if (block->b_when == NLM_NEVER)
709                         break;
710                 if (time_after(block->b_when,jiffies))
711                         break;
712                 dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n",
713                         block, block->b_when, block->b_done);
714                 kref_get(&block->b_count);
715                 if (block->b_done)
716                         nlmsvc_unlink_block(block);
717                 else
718                         nlmsvc_grant_blocked(block);
719                 nlmsvc_release_block(block);
720         }
721
722         if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
723                 return (block->b_when - jiffies);
724
725         return MAX_SCHEDULE_TIMEOUT;
726 }