2 * linux/fs/lockd/svclock.c
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.
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.
20 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
23 #include <linux/types.h>
24 #include <linux/slab.h>
25 #include <linux/errno.h>
26 #include <linux/kernel.h>
27 #include <linux/sched.h>
28 #include <linux/sunrpc/clnt.h>
29 #include <linux/sunrpc/svc_xprt.h>
30 #include <linux/lockd/nlm.h>
31 #include <linux/lockd/lockd.h>
32 #include <linux/kthread.h>
34 #define NLMDBG_FACILITY NLMDBG_SVCLOCK
36 #ifdef CONFIG_LOCKD_V4
37 #define nlm_deadlock nlm4_deadlock
39 #define nlm_deadlock nlm_lck_denied
42 static void nlmsvc_release_block(struct nlm_block *block);
43 static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
44 static void nlmsvc_remove_block(struct nlm_block *block);
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;
51 * The list of blocked locks to retry
53 static LIST_HEAD(nlm_blocked);
54 static DEFINE_SPINLOCK(nlm_blocked_lock);
57 static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie)
60 * We can get away with a static buffer because we're only
61 * called with BKL held.
63 static char buf[2*NLM_MAXCOOKIELEN+1];
64 unsigned int i, len = sizeof(buf);
67 len--; /* allow for trailing \0 */
70 for (i = 0 ; i < cookie->len ; i++) {
75 sprintf(p, "%02x", cookie->data[i]);
86 * Insert a blocked lock into the global list
89 nlmsvc_insert_block_locked(struct nlm_block *block, unsigned long when)
92 struct list_head *pos;
94 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
95 if (list_empty(&block->b_list)) {
96 kref_get(&block->b_count);
98 list_del_init(&block->b_list);
102 if (when != NLM_NEVER) {
103 if ((when += jiffies) == NLM_NEVER)
105 list_for_each(pos, &nlm_blocked) {
106 b = list_entry(pos, struct nlm_block, b_list);
107 if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
110 /* On normal exit from the loop, pos == &nlm_blocked,
111 * so we will be adding to the end of the list - good
115 list_add_tail(&block->b_list, pos);
116 block->b_when = when;
119 static void nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
121 spin_lock(&nlm_blocked_lock);
122 nlmsvc_insert_block_locked(block, when);
123 spin_unlock(&nlm_blocked_lock);
127 * Remove a block from the global list
130 nlmsvc_remove_block(struct nlm_block *block)
132 if (!list_empty(&block->b_list)) {
133 spin_lock(&nlm_blocked_lock);
134 list_del_init(&block->b_list);
135 spin_unlock(&nlm_blocked_lock);
136 nlmsvc_release_block(block);
141 * Find a block for a given lock
143 static struct nlm_block *
144 nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
146 struct nlm_block *block;
147 struct file_lock *fl;
149 dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
150 file, lock->fl.fl_pid,
151 (long long)lock->fl.fl_start,
152 (long long)lock->fl.fl_end, lock->fl.fl_type);
153 list_for_each_entry(block, &nlm_blocked, b_list) {
154 fl = &block->b_call->a_args.lock.fl;
155 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
156 block->b_file, fl->fl_pid,
157 (long long)fl->fl_start,
158 (long long)fl->fl_end, fl->fl_type,
159 nlmdbg_cookie2a(&block->b_call->a_args.cookie));
160 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
161 kref_get(&block->b_count);
169 static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
171 if (a->len != b->len)
173 if (memcmp(a->data, b->data, a->len))
179 * Find a block with a given NLM cookie.
181 static inline struct nlm_block *
182 nlmsvc_find_block(struct nlm_cookie *cookie)
184 struct nlm_block *block;
186 list_for_each_entry(block, &nlm_blocked, b_list) {
187 if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie))
194 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block);
195 kref_get(&block->b_count);
200 * Create a block and initialize it.
202 * Note: we explicitly set the cookie of the grant reply to that of
203 * the blocked lock request. The spec explicitly mentions that the client
204 * should _not_ rely on the callback containing the same cookie as the
205 * request, but (as I found out later) that's because some implementations
206 * do just this. Never mind the standards comittees, they support our
207 * logging industries.
209 * 10 years later: I hope we can safely ignore these old and broken
210 * clients by now. Let's fix this so we can uniquely identify an incoming
211 * GRANTED_RES message by cookie, without having to rely on the client's IP
214 static struct nlm_block *
215 nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host,
216 struct nlm_file *file, struct nlm_lock *lock,
217 struct nlm_cookie *cookie)
219 struct nlm_block *block;
220 struct nlm_rqst *call = NULL;
222 call = nlm_alloc_call(host);
226 /* Allocate memory for block, and initialize arguments */
227 block = kzalloc(sizeof(*block), GFP_KERNEL);
230 kref_init(&block->b_count);
231 INIT_LIST_HEAD(&block->b_list);
232 INIT_LIST_HEAD(&block->b_flist);
234 if (!nlmsvc_setgrantargs(call, lock))
237 /* Set notifier function for VFS, and init args */
238 call->a_args.lock.fl.fl_flags |= FL_SLEEP;
239 call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
240 nlmclnt_next_cookie(&call->a_args.cookie);
242 dprintk("lockd: created block %p...\n", block);
244 /* Create and initialize the block */
245 block->b_daemon = rqstp->rq_server;
246 block->b_host = host;
247 block->b_file = file;
251 /* Add to file's list of blocks */
252 list_add(&block->b_flist, &file->f_blocks);
254 /* Set up RPC arguments for callback */
255 block->b_call = call;
256 call->a_flags = RPC_TASK_ASYNC;
257 call->a_block = block;
264 nlmsvc_release_call(call);
270 * It is the caller's responsibility to check whether the file
271 * can be closed hereafter.
273 static int nlmsvc_unlink_block(struct nlm_block *block)
276 dprintk("lockd: unlinking block %p...\n", block);
278 /* Remove block from list */
279 status = posix_unblock_lock(&block->b_call->a_args.lock.fl);
280 nlmsvc_remove_block(block);
284 static void nlmsvc_free_block(struct kref *kref)
286 struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
287 struct nlm_file *file = block->b_file;
289 dprintk("lockd: freeing block %p...\n", block);
291 /* Remove block from file's list of blocks */
292 list_del_init(&block->b_flist);
293 mutex_unlock(&file->f_mutex);
295 nlmsvc_freegrantargs(block->b_call);
296 nlmsvc_release_call(block->b_call);
297 nlm_release_file(block->b_file);
302 static void nlmsvc_release_block(struct nlm_block *block)
305 kref_put_mutex(&block->b_count, nlmsvc_free_block, &block->b_file->f_mutex);
309 * Loop over all blocks and delete blocks held by
312 void nlmsvc_traverse_blocks(struct nlm_host *host,
313 struct nlm_file *file,
314 nlm_host_match_fn_t match)
316 struct nlm_block *block, *next;
319 mutex_lock(&file->f_mutex);
320 list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
321 if (!match(block->b_host, host))
323 /* Do not destroy blocks that are not on
324 * the global retry list - why? */
325 if (list_empty(&block->b_list))
327 kref_get(&block->b_count);
328 mutex_unlock(&file->f_mutex);
329 nlmsvc_unlink_block(block);
330 nlmsvc_release_block(block);
333 mutex_unlock(&file->f_mutex);
337 * Initialize arguments for GRANTED call. The nlm_rqst structure
338 * has been cleared already.
340 static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
342 locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
343 memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
344 call->a_args.lock.caller = utsname()->nodename;
345 call->a_args.lock.oh.len = lock->oh.len;
347 /* set default data area */
348 call->a_args.lock.oh.data = call->a_owner;
349 call->a_args.lock.svid = lock->fl.fl_pid;
351 if (lock->oh.len > NLMCLNT_OHSIZE) {
352 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
355 call->a_args.lock.oh.data = (u8 *) data;
358 memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
362 static void nlmsvc_freegrantargs(struct nlm_rqst *call)
364 if (call->a_args.lock.oh.data != call->a_owner)
365 kfree(call->a_args.lock.oh.data);
367 locks_release_private(&call->a_args.lock.fl);
371 * Deferred lock request handling for non-blocking lock
374 nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
376 __be32 status = nlm_lck_denied_nolocks;
378 block->b_flags |= B_QUEUED;
380 nlmsvc_insert_block(block, NLM_TIMEOUT);
382 block->b_cache_req = &rqstp->rq_chandle;
383 if (rqstp->rq_chandle.defer) {
384 block->b_deferred_req =
385 rqstp->rq_chandle.defer(block->b_cache_req);
386 if (block->b_deferred_req != NULL)
387 status = nlm_drop_reply;
389 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
390 block, block->b_flags, ntohl(status));
396 * Attempt to establish a lock, and if it can't be granted, block it
400 nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
401 struct nlm_host *host, struct nlm_lock *lock, int wait,
402 struct nlm_cookie *cookie, int reclaim)
404 struct nlm_block *block = NULL;
408 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
409 file_inode(file->f_file)->i_sb->s_id,
410 file_inode(file->f_file)->i_ino,
411 lock->fl.fl_type, lock->fl.fl_pid,
412 (long long)lock->fl.fl_start,
413 (long long)lock->fl.fl_end,
416 /* Lock file against concurrent access */
417 mutex_lock(&file->f_mutex);
418 /* Get existing block (in case client is busy-waiting)
419 * or create new block
421 block = nlmsvc_lookup_block(file, lock);
423 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
424 ret = nlm_lck_denied_nolocks;
427 lock = &block->b_call->a_args.lock;
429 lock->fl.fl_flags &= ~FL_SLEEP;
431 if (block->b_flags & B_QUEUED) {
432 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
433 block, block->b_flags);
434 if (block->b_granted) {
435 nlmsvc_unlink_block(block);
439 if (block->b_flags & B_TIMED_OUT) {
440 nlmsvc_unlink_block(block);
441 ret = nlm_lck_denied;
444 ret = nlm_drop_reply;
448 if (locks_in_grace(SVC_NET(rqstp)) && !reclaim) {
449 ret = nlm_lck_denied_grace_period;
452 if (reclaim && !locks_in_grace(SVC_NET(rqstp))) {
453 ret = nlm_lck_denied_grace_period;
458 lock->fl.fl_flags &= ~FL_SLEEP;
459 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
460 lock->fl.fl_flags &= ~FL_SLEEP;
462 dprintk("lockd: vfs_lock_file returned %d\n", error);
469 * If this is a blocking request for an
470 * already pending lock request then we need
471 * to put it back on lockd's block list
475 ret = nlm_lck_denied;
477 case FILE_LOCK_DEFERRED:
480 /* Filesystem lock operation is in progress
481 Add it to the queue waiting for callback */
482 ret = nlmsvc_defer_lock_rqst(rqstp, block);
487 default: /* includes ENOLCK */
488 ret = nlm_lck_denied_nolocks;
492 ret = nlm_lck_blocked;
494 /* Append to list of blocked */
495 nlmsvc_insert_block(block, NLM_NEVER);
497 mutex_unlock(&file->f_mutex);
498 nlmsvc_release_block(block);
499 dprintk("lockd: nlmsvc_lock returned %u\n", ret);
504 * Test for presence of a conflicting lock.
507 nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
508 struct nlm_host *host, struct nlm_lock *lock,
509 struct nlm_lock *conflock, struct nlm_cookie *cookie)
511 struct nlm_block *block = NULL;
515 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
516 file_inode(file->f_file)->i_sb->s_id,
517 file_inode(file->f_file)->i_ino,
519 (long long)lock->fl.fl_start,
520 (long long)lock->fl.fl_end);
522 /* Get existing block (in case client is busy-waiting) */
523 block = nlmsvc_lookup_block(file, lock);
526 struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
530 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
537 if (block->b_flags & B_QUEUED) {
538 dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
539 block, block->b_flags, block->b_fl);
540 if (block->b_flags & B_TIMED_OUT) {
541 nlmsvc_unlink_block(block);
542 ret = nlm_lck_denied;
545 if (block->b_flags & B_GOT_CALLBACK) {
546 nlmsvc_unlink_block(block);
547 if (block->b_fl != NULL
548 && block->b_fl->fl_type != F_UNLCK) {
549 lock->fl = *block->b_fl;
556 ret = nlm_drop_reply;
560 if (locks_in_grace(SVC_NET(rqstp))) {
561 ret = nlm_lck_denied_grace_period;
564 error = vfs_test_lock(file->f_file, &lock->fl);
565 if (error == FILE_LOCK_DEFERRED) {
566 ret = nlmsvc_defer_lock_rqst(rqstp, block);
570 ret = nlm_lck_denied_nolocks;
573 if (lock->fl.fl_type == F_UNLCK) {
579 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
580 lock->fl.fl_type, (long long)lock->fl.fl_start,
581 (long long)lock->fl.fl_end);
582 conflock->caller = "somehost"; /* FIXME */
583 conflock->len = strlen(conflock->caller);
584 conflock->oh.len = 0; /* don't return OH info */
585 conflock->svid = lock->fl.fl_pid;
586 conflock->fl.fl_type = lock->fl.fl_type;
587 conflock->fl.fl_start = lock->fl.fl_start;
588 conflock->fl.fl_end = lock->fl.fl_end;
589 ret = nlm_lck_denied;
592 nlmsvc_release_block(block);
598 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
599 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
600 * afterwards. In this case the block will still be there, and hence
604 nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
608 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
609 file_inode(file->f_file)->i_sb->s_id,
610 file_inode(file->f_file)->i_ino,
612 (long long)lock->fl.fl_start,
613 (long long)lock->fl.fl_end);
615 /* First, cancel any lock that might be there */
616 nlmsvc_cancel_blocked(net, file, lock);
618 lock->fl.fl_type = F_UNLCK;
619 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
621 return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
625 * Cancel a previously blocked request.
627 * A cancel request always overrides any grant that may currently
629 * The calling procedure must check whether the file can be closed.
632 nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
634 struct nlm_block *block;
637 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
638 file_inode(file->f_file)->i_sb->s_id,
639 file_inode(file->f_file)->i_ino,
641 (long long)lock->fl.fl_start,
642 (long long)lock->fl.fl_end);
644 if (locks_in_grace(net))
645 return nlm_lck_denied_grace_period;
647 mutex_lock(&file->f_mutex);
648 block = nlmsvc_lookup_block(file, lock);
649 mutex_unlock(&file->f_mutex);
651 vfs_cancel_lock(block->b_file->f_file,
652 &block->b_call->a_args.lock.fl);
653 status = nlmsvc_unlink_block(block);
654 nlmsvc_release_block(block);
656 return status ? nlm_lck_denied : nlm_granted;
660 * This is a callback from the filesystem for VFS file lock requests.
661 * It will be used if lm_grant is defined and the filesystem can not
662 * respond to the request immediately.
663 * For GETLK request it will copy the reply to the nlm_block.
664 * For SETLK or SETLKW request it will get the local posix lock.
665 * In all cases it will move the block to the head of nlm_blocked q where
666 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
667 * deferred rpc for GETLK and SETLK.
670 nlmsvc_update_deferred_block(struct nlm_block *block, int result)
672 block->b_flags |= B_GOT_CALLBACK;
674 block->b_granted = 1;
676 block->b_flags |= B_TIMED_OUT;
679 static int nlmsvc_grant_deferred(struct file_lock *fl, int result)
681 struct nlm_block *block;
684 spin_lock(&nlm_blocked_lock);
685 list_for_each_entry(block, &nlm_blocked, b_list) {
686 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
687 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
688 block, block->b_flags);
689 if (block->b_flags & B_QUEUED) {
690 if (block->b_flags & B_TIMED_OUT) {
694 nlmsvc_update_deferred_block(block, result);
695 } else if (result == 0)
696 block->b_granted = 1;
698 nlmsvc_insert_block_locked(block, 0);
699 svc_wake_up(block->b_daemon);
704 spin_unlock(&nlm_blocked_lock);
706 printk(KERN_WARNING "lockd: grant for unknown block\n");
711 * Unblock a blocked lock request. This is a callback invoked from the
712 * VFS layer when a lock on which we blocked is removed.
714 * This function doesn't grant the blocked lock instantly, but rather moves
715 * the block to the head of nlm_blocked where it can be picked up by lockd.
718 nlmsvc_notify_blocked(struct file_lock *fl)
720 struct nlm_block *block;
722 dprintk("lockd: VFS unblock notification for block %p\n", fl);
723 spin_lock(&nlm_blocked_lock);
724 list_for_each_entry(block, &nlm_blocked, b_list) {
725 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
726 nlmsvc_insert_block_locked(block, 0);
727 spin_unlock(&nlm_blocked_lock);
728 svc_wake_up(block->b_daemon);
732 spin_unlock(&nlm_blocked_lock);
733 printk(KERN_WARNING "lockd: notification for unknown block!\n");
736 static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
738 return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
742 * Since NLM uses two "keys" for tracking locks, we need to hash them down
743 * to one for the blocked_hash. Here, we're just xor'ing the host address
744 * with the pid in order to create a key value for picking a hash bucket.
747 nlmsvc_owner_key(struct file_lock *fl)
749 return (unsigned long)fl->fl_owner ^ (unsigned long)fl->fl_pid;
752 const struct lock_manager_operations nlmsvc_lock_operations = {
753 .lm_compare_owner = nlmsvc_same_owner,
754 .lm_owner_key = nlmsvc_owner_key,
755 .lm_notify = nlmsvc_notify_blocked,
756 .lm_grant = nlmsvc_grant_deferred,
760 * Try to claim a lock that was previously blocked.
762 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
763 * RPC thread when notifying the client. This seems like overkill...
765 * - we don't want to use a synchronous RPC thread, otherwise
766 * we might find ourselves hanging on a dead portmapper.
767 * - Some lockd implementations (e.g. HP) don't react to
768 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
771 nlmsvc_grant_blocked(struct nlm_block *block)
773 struct nlm_file *file = block->b_file;
774 struct nlm_lock *lock = &block->b_call->a_args.lock;
776 loff_t fl_start, fl_end;
778 dprintk("lockd: grant blocked lock %p\n", block);
780 kref_get(&block->b_count);
782 /* Unlink block request from list */
783 nlmsvc_unlink_block(block);
785 /* If b_granted is true this means we've been here before.
786 * Just retry the grant callback, possibly refreshing the RPC
788 if (block->b_granted) {
789 nlm_rebind_host(block->b_host);
793 /* Try the lock operation again */
794 /* vfs_lock_file() can mangle fl_start and fl_end, but we need
795 * them unchanged for the GRANT_MSG
797 lock->fl.fl_flags |= FL_SLEEP;
798 fl_start = lock->fl.fl_start;
799 fl_end = lock->fl.fl_end;
800 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
801 lock->fl.fl_flags &= ~FL_SLEEP;
802 lock->fl.fl_start = fl_start;
803 lock->fl.fl_end = fl_end;
808 case FILE_LOCK_DEFERRED:
809 dprintk("lockd: lock still blocked error %d\n", error);
810 nlmsvc_insert_block(block, NLM_NEVER);
811 nlmsvc_release_block(block);
814 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
816 nlmsvc_insert_block(block, 10 * HZ);
817 nlmsvc_release_block(block);
822 /* Lock was granted by VFS. */
823 dprintk("lockd: GRANTing blocked lock.\n");
824 block->b_granted = 1;
826 /* keep block on the list, but don't reattempt until the RPC
827 * completes or the submission fails
829 nlmsvc_insert_block(block, NLM_NEVER);
831 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
832 * will queue up a new one if this one times out
834 error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
837 /* RPC submission failed, wait a bit and retry */
839 nlmsvc_insert_block(block, 10 * HZ);
843 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
844 * RPC call has succeeded or timed out.
845 * Like all RPC callbacks, it is invoked by the rpciod process, so it
846 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
847 * chain once more in order to have it removed by lockd itself (which can
848 * then sleep on the file semaphore without disrupting e.g. the nfs client).
850 static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
852 struct nlm_rqst *call = data;
853 struct nlm_block *block = call->a_block;
854 unsigned long timeout;
856 dprintk("lockd: GRANT_MSG RPC callback\n");
858 spin_lock(&nlm_blocked_lock);
859 /* if the block is not on a list at this point then it has
860 * been invalidated. Don't try to requeue it.
862 * FIXME: it's possible that the block is removed from the list
863 * after this check but before the nlmsvc_insert_block. In that
864 * case it will be added back. Perhaps we need better locking
867 if (list_empty(&block->b_list))
870 /* Technically, we should down the file semaphore here. Since we
871 * move the block towards the head of the queue only, no harm
872 * can be done, though. */
873 if (task->tk_status < 0) {
874 /* RPC error: Re-insert for retransmission */
877 /* Call was successful, now wait for client callback */
880 nlmsvc_insert_block_locked(block, timeout);
881 svc_wake_up(block->b_daemon);
883 spin_unlock(&nlm_blocked_lock);
887 * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an
888 * .rpc_release rpc_call_op
890 static void nlmsvc_grant_release(void *data)
892 struct nlm_rqst *call = data;
893 nlmsvc_release_block(call->a_block);
896 static const struct rpc_call_ops nlmsvc_grant_ops = {
897 .rpc_call_done = nlmsvc_grant_callback,
898 .rpc_release = nlmsvc_grant_release,
902 * We received a GRANT_RES callback. Try to find the corresponding
906 nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
908 struct nlm_block *block;
910 dprintk("grant_reply: looking for cookie %x, s=%d \n",
911 *(unsigned int *)(cookie->data), status);
912 if (!(block = nlmsvc_find_block(cookie)))
916 if (status == nlm_lck_denied_grace_period) {
917 /* Try again in a couple of seconds */
918 nlmsvc_insert_block(block, 10 * HZ);
920 /* Lock is now held by client, or has been rejected.
921 * In both cases, the block should be removed. */
922 nlmsvc_unlink_block(block);
925 nlmsvc_release_block(block);
928 /* Helper function to handle retry of a deferred block.
929 * If it is a blocking lock, call grant_blocked.
930 * For a non-blocking lock or test lock, revisit the request.
933 retry_deferred_block(struct nlm_block *block)
935 if (!(block->b_flags & B_GOT_CALLBACK))
936 block->b_flags |= B_TIMED_OUT;
937 nlmsvc_insert_block(block, NLM_TIMEOUT);
938 dprintk("revisit block %p flags %d\n", block, block->b_flags);
939 if (block->b_deferred_req) {
940 block->b_deferred_req->revisit(block->b_deferred_req, 0);
941 block->b_deferred_req = NULL;
946 * Retry all blocked locks that have been notified. This is where lockd
947 * picks up locks that can be granted, or grant notifications that must
951 nlmsvc_retry_blocked(void)
953 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
954 struct nlm_block *block;
956 spin_lock(&nlm_blocked_lock);
957 while (!list_empty(&nlm_blocked) && !kthread_should_stop()) {
958 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
960 if (block->b_when == NLM_NEVER)
962 if (time_after(block->b_when, jiffies)) {
963 timeout = block->b_when - jiffies;
966 spin_unlock(&nlm_blocked_lock);
968 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
969 block, block->b_when);
970 if (block->b_flags & B_QUEUED) {
971 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
972 block, block->b_granted, block->b_flags);
973 retry_deferred_block(block);
975 nlmsvc_grant_blocked(block);
976 spin_lock(&nlm_blocked_lock);
978 spin_unlock(&nlm_blocked_lock);