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/errno.h>
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/smp_lock.h>
28 #include <linux/sunrpc/clnt.h>
29 #include <linux/sunrpc/svc.h>
30 #include <linux/lockd/nlm.h>
31 #include <linux/lockd/lockd.h>
33 #define NLMDBG_FACILITY NLMDBG_SVCLOCK
35 #ifdef CONFIG_LOCKD_V4
36 #define nlm_deadlock nlm4_deadlock
38 #define nlm_deadlock nlm_lck_denied
41 static void nlmsvc_release_block(struct nlm_block
*block
);
42 static void nlmsvc_insert_block(struct nlm_block
*block
, unsigned long);
43 static void nlmsvc_remove_block(struct nlm_block
*block
);
45 static int nlmsvc_setgrantargs(struct nlm_rqst
*call
, struct nlm_lock
*lock
);
46 static void nlmsvc_freegrantargs(struct nlm_rqst
*call
);
47 static const struct rpc_call_ops nlmsvc_grant_ops
;
50 * The list of blocked locks to retry
52 static LIST_HEAD(nlm_blocked
);
55 * Insert a blocked lock into the global list
58 nlmsvc_insert_block(struct nlm_block
*block
, unsigned long when
)
61 struct list_head
*pos
;
63 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block
, when
);
64 if (list_empty(&block
->b_list
)) {
65 kref_get(&block
->b_count
);
67 list_del_init(&block
->b_list
);
71 if (when
!= NLM_NEVER
) {
72 if ((when
+= jiffies
) == NLM_NEVER
)
74 list_for_each(pos
, &nlm_blocked
) {
75 b
= list_entry(pos
, struct nlm_block
, b_list
);
76 if (time_after(b
->b_when
,when
) || b
->b_when
== NLM_NEVER
)
79 /* On normal exit from the loop, pos == &nlm_blocked,
80 * so we will be adding to the end of the list - good
84 list_add_tail(&block
->b_list
, pos
);
89 * Remove a block from the global list
92 nlmsvc_remove_block(struct nlm_block
*block
)
94 if (!list_empty(&block
->b_list
)) {
95 list_del_init(&block
->b_list
);
96 nlmsvc_release_block(block
);
101 * Find a block for a given lock
103 static struct nlm_block
*
104 nlmsvc_lookup_block(struct nlm_file
*file
, struct nlm_lock
*lock
)
106 struct nlm_block
*block
;
107 struct file_lock
*fl
;
109 dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
110 file
, lock
->fl
.fl_pid
,
111 (long long)lock
->fl
.fl_start
,
112 (long long)lock
->fl
.fl_end
, lock
->fl
.fl_type
);
113 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
114 fl
= &block
->b_call
->a_args
.lock
.fl
;
115 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
116 block
->b_file
, fl
->fl_pid
,
117 (long long)fl
->fl_start
,
118 (long long)fl
->fl_end
, fl
->fl_type
,
119 nlmdbg_cookie2a(&block
->b_call
->a_args
.cookie
));
120 if (block
->b_file
== file
&& nlm_compare_locks(fl
, &lock
->fl
)) {
121 kref_get(&block
->b_count
);
129 static inline int nlm_cookie_match(struct nlm_cookie
*a
, struct nlm_cookie
*b
)
133 if(memcmp(a
->data
,b
->data
,a
->len
))
139 * Find a block with a given NLM cookie.
141 static inline struct nlm_block
*
142 nlmsvc_find_block(struct nlm_cookie
*cookie
)
144 struct nlm_block
*block
;
146 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
147 if (nlm_cookie_match(&block
->b_call
->a_args
.cookie
,cookie
))
154 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie
), block
);
155 kref_get(&block
->b_count
);
160 * Create a block and initialize it.
162 * Note: we explicitly set the cookie of the grant reply to that of
163 * the blocked lock request. The spec explicitly mentions that the client
164 * should _not_ rely on the callback containing the same cookie as the
165 * request, but (as I found out later) that's because some implementations
166 * do just this. Never mind the standards comittees, they support our
167 * logging industries.
169 * 10 years later: I hope we can safely ignore these old and broken
170 * clients by now. Let's fix this so we can uniquely identify an incoming
171 * GRANTED_RES message by cookie, without having to rely on the client's IP
174 static inline struct nlm_block
*
175 nlmsvc_create_block(struct svc_rqst
*rqstp
, struct nlm_file
*file
,
176 struct nlm_lock
*lock
, struct nlm_cookie
*cookie
)
178 struct nlm_block
*block
;
179 struct nlm_host
*host
;
180 struct nlm_rqst
*call
= NULL
;
182 /* Create host handle for callback */
183 host
= nlmsvc_lookup_host(rqstp
, lock
->caller
, lock
->len
);
187 call
= nlm_alloc_call(host
);
191 /* Allocate memory for block, and initialize arguments */
192 block
= kzalloc(sizeof(*block
), GFP_KERNEL
);
195 kref_init(&block
->b_count
);
196 INIT_LIST_HEAD(&block
->b_list
);
197 INIT_LIST_HEAD(&block
->b_flist
);
199 if (!nlmsvc_setgrantargs(call
, lock
))
202 /* Set notifier function for VFS, and init args */
203 call
->a_args
.lock
.fl
.fl_flags
|= FL_SLEEP
;
204 call
->a_args
.lock
.fl
.fl_lmops
= &nlmsvc_lock_operations
;
205 nlmclnt_next_cookie(&call
->a_args
.cookie
);
207 dprintk("lockd: created block %p...\n", block
);
209 /* Create and initialize the block */
210 block
->b_daemon
= rqstp
->rq_server
;
211 block
->b_host
= host
;
212 block
->b_file
= file
;
215 /* Add to file's list of blocks */
216 list_add(&block
->b_flist
, &file
->f_blocks
);
218 /* Set up RPC arguments for callback */
219 block
->b_call
= call
;
220 call
->a_flags
= RPC_TASK_ASYNC
;
221 call
->a_block
= block
;
228 nlm_release_call(call
);
233 * Delete a block. If the lock was cancelled or the grant callback
234 * failed, unlock is set to 1.
235 * It is the caller's responsibility to check whether the file
236 * can be closed hereafter.
238 static int nlmsvc_unlink_block(struct nlm_block
*block
)
241 dprintk("lockd: unlinking block %p...\n", block
);
243 /* Remove block from list */
244 status
= posix_unblock_lock(block
->b_file
->f_file
, &block
->b_call
->a_args
.lock
.fl
);
245 nlmsvc_remove_block(block
);
249 static void nlmsvc_free_block(struct kref
*kref
)
251 struct nlm_block
*block
= container_of(kref
, struct nlm_block
, b_count
);
252 struct nlm_file
*file
= block
->b_file
;
254 dprintk("lockd: freeing block %p...\n", block
);
256 /* Remove block from file's list of blocks */
257 mutex_lock(&file
->f_mutex
);
258 list_del_init(&block
->b_flist
);
259 mutex_unlock(&file
->f_mutex
);
261 nlmsvc_freegrantargs(block
->b_call
);
262 nlm_release_call(block
->b_call
);
263 nlm_release_file(block
->b_file
);
268 static void nlmsvc_release_block(struct nlm_block
*block
)
271 kref_put(&block
->b_count
, nlmsvc_free_block
);
275 * Loop over all blocks and delete blocks held by
278 void nlmsvc_traverse_blocks(struct nlm_host
*host
,
279 struct nlm_file
*file
,
280 nlm_host_match_fn_t match
)
282 struct nlm_block
*block
, *next
;
285 mutex_lock(&file
->f_mutex
);
286 list_for_each_entry_safe(block
, next
, &file
->f_blocks
, b_flist
) {
287 if (!match(block
->b_host
, host
))
289 /* Do not destroy blocks that are not on
290 * the global retry list - why? */
291 if (list_empty(&block
->b_list
))
293 kref_get(&block
->b_count
);
294 mutex_unlock(&file
->f_mutex
);
295 nlmsvc_unlink_block(block
);
296 nlmsvc_release_block(block
);
299 mutex_unlock(&file
->f_mutex
);
303 * Initialize arguments for GRANTED call. The nlm_rqst structure
304 * has been cleared already.
306 static int nlmsvc_setgrantargs(struct nlm_rqst
*call
, struct nlm_lock
*lock
)
308 locks_copy_lock(&call
->a_args
.lock
.fl
, &lock
->fl
);
309 memcpy(&call
->a_args
.lock
.fh
, &lock
->fh
, sizeof(call
->a_args
.lock
.fh
));
310 call
->a_args
.lock
.caller
= utsname()->nodename
;
311 call
->a_args
.lock
.oh
.len
= lock
->oh
.len
;
313 /* set default data area */
314 call
->a_args
.lock
.oh
.data
= call
->a_owner
;
315 call
->a_args
.lock
.svid
= lock
->fl
.fl_pid
;
317 if (lock
->oh
.len
> NLMCLNT_OHSIZE
) {
318 void *data
= kmalloc(lock
->oh
.len
, GFP_KERNEL
);
321 call
->a_args
.lock
.oh
.data
= (u8
*) data
;
324 memcpy(call
->a_args
.lock
.oh
.data
, lock
->oh
.data
, lock
->oh
.len
);
328 static void nlmsvc_freegrantargs(struct nlm_rqst
*call
)
330 if (call
->a_args
.lock
.oh
.data
!= call
->a_owner
)
331 kfree(call
->a_args
.lock
.oh
.data
);
335 * Deferred lock request handling for non-blocking lock
338 nlmsvc_defer_lock_rqst(struct svc_rqst
*rqstp
, struct nlm_block
*block
)
340 u32 status
= nlm_lck_denied_nolocks
;
342 block
->b_flags
|= B_QUEUED
;
344 nlmsvc_insert_block(block
, NLM_TIMEOUT
);
346 block
->b_cache_req
= &rqstp
->rq_chandle
;
347 if (rqstp
->rq_chandle
.defer
) {
348 block
->b_deferred_req
=
349 rqstp
->rq_chandle
.defer(block
->b_cache_req
);
350 if (block
->b_deferred_req
!= NULL
)
351 status
= nlm_drop_reply
;
353 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
354 block
, block
->b_flags
, status
);
360 * Attempt to establish a lock, and if it can't be granted, block it
364 nlmsvc_lock(struct svc_rqst
*rqstp
, struct nlm_file
*file
,
365 struct nlm_lock
*lock
, int wait
, struct nlm_cookie
*cookie
)
367 struct nlm_block
*block
, *newblock
= NULL
;
371 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
372 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
373 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
374 lock
->fl
.fl_type
, lock
->fl
.fl_pid
,
375 (long long)lock
->fl
.fl_start
,
376 (long long)lock
->fl
.fl_end
,
380 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
382 /* Lock file against concurrent access */
383 mutex_lock(&file
->f_mutex
);
384 /* Get existing block (in case client is busy-waiting) */
385 block
= nlmsvc_lookup_block(file
, lock
);
387 if (newblock
!= NULL
)
388 lock
= &newblock
->b_call
->a_args
.lock
;
390 lock
= &block
->b_call
->a_args
.lock
;
392 error
= posix_lock_file(file
->f_file
, &lock
->fl
, NULL
);
393 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
395 dprintk("lockd: posix_lock_file returned %d\n", error
);
406 default: /* includes ENOLCK */
407 ret
= nlm_lck_denied_nolocks
;
411 ret
= nlm_lck_denied
;
415 ret
= nlm_lck_blocked
;
419 /* If we don't have a block, create and initialize it. Then
420 * retry because we may have slept in kmalloc. */
421 /* We have to release f_mutex as nlmsvc_create_block may try to
422 * to claim it while doing host garbage collection */
423 if (newblock
== NULL
) {
424 mutex_unlock(&file
->f_mutex
);
425 dprintk("lockd: blocking on this lock (allocating).\n");
426 if (!(newblock
= nlmsvc_create_block(rqstp
, file
, lock
, cookie
)))
427 return nlm_lck_denied_nolocks
;
431 /* Append to list of blocked */
432 nlmsvc_insert_block(newblock
, NLM_NEVER
);
434 mutex_unlock(&file
->f_mutex
);
435 nlmsvc_release_block(newblock
);
436 nlmsvc_release_block(block
);
437 dprintk("lockd: nlmsvc_lock returned %u\n", ret
);
442 * Test for presence of a conflicting lock.
445 nlmsvc_testlock(struct nlm_file
*file
, struct nlm_lock
*lock
,
446 struct nlm_lock
*conflock
)
448 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
449 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
450 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
452 (long long)lock
->fl
.fl_start
,
453 (long long)lock
->fl
.fl_end
);
455 if (posix_test_lock(file
->f_file
, &lock
->fl
)) {
456 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
458 (long long)lock
->fl
.fl_start
,
459 (long long)lock
->fl
.fl_end
);
460 conflock
->caller
= "somehost"; /* FIXME */
461 conflock
->len
= strlen(conflock
->caller
);
462 conflock
->oh
.len
= 0; /* don't return OH info */
463 conflock
->svid
= lock
->fl
.fl_pid
;
464 conflock
->fl
.fl_type
= lock
->fl
.fl_type
;
465 conflock
->fl
.fl_start
= lock
->fl
.fl_start
;
466 conflock
->fl
.fl_end
= lock
->fl
.fl_end
;
467 return nlm_lck_denied
;
475 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
476 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
477 * afterwards. In this case the block will still be there, and hence
481 nlmsvc_unlock(struct nlm_file
*file
, struct nlm_lock
*lock
)
485 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
486 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
487 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
489 (long long)lock
->fl
.fl_start
,
490 (long long)lock
->fl
.fl_end
);
492 /* First, cancel any lock that might be there */
493 nlmsvc_cancel_blocked(file
, lock
);
495 lock
->fl
.fl_type
= F_UNLCK
;
496 error
= posix_lock_file(file
->f_file
, &lock
->fl
, NULL
);
498 return (error
< 0)? nlm_lck_denied_nolocks
: nlm_granted
;
502 * Cancel a previously blocked request.
504 * A cancel request always overrides any grant that may currently
506 * The calling procedure must check whether the file can be closed.
509 nlmsvc_cancel_blocked(struct nlm_file
*file
, struct nlm_lock
*lock
)
511 struct nlm_block
*block
;
514 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
515 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
516 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
518 (long long)lock
->fl
.fl_start
,
519 (long long)lock
->fl
.fl_end
);
521 mutex_lock(&file
->f_mutex
);
522 block
= nlmsvc_lookup_block(file
, lock
);
523 mutex_unlock(&file
->f_mutex
);
525 status
= nlmsvc_unlink_block(block
);
526 nlmsvc_release_block(block
);
528 return status
? nlm_lck_denied
: nlm_granted
;
532 * This is a callback from the filesystem for VFS file lock requests.
533 * It will be used if fl_grant is defined and the filesystem can not
534 * respond to the request immediately.
535 * For GETLK request it will copy the reply to the nlm_block.
536 * For SETLK or SETLKW request it will get the local posix lock.
537 * In all cases it will move the block to the head of nlm_blocked q where
538 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
539 * deferred rpc for GETLK and SETLK.
542 nlmsvc_update_deferred_block(struct nlm_block
*block
, struct file_lock
*conf
,
545 block
->b_flags
|= B_GOT_CALLBACK
;
547 block
->b_granted
= 1;
549 block
->b_flags
|= B_TIMED_OUT
;
551 block
->b_fl
= kzalloc(sizeof(struct file_lock
), GFP_KERNEL
);
553 locks_copy_lock(block
->b_fl
, conf
);
557 static int nlmsvc_grant_deferred(struct file_lock
*fl
, struct file_lock
*conf
,
560 struct nlm_block
*block
;
564 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
565 if (nlm_compare_locks(&block
->b_call
->a_args
.lock
.fl
, fl
)) {
566 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
567 block
, block
->b_flags
);
568 if (block
->b_flags
& B_QUEUED
) {
569 if (block
->b_flags
& B_TIMED_OUT
) {
573 nlmsvc_update_deferred_block(block
, conf
, result
);
574 } else if (result
== 0)
575 block
->b_granted
= 1;
577 nlmsvc_insert_block(block
, 0);
578 svc_wake_up(block
->b_daemon
);
585 printk(KERN_WARNING
"lockd: grant for unknown block\n");
590 * Unblock a blocked lock request. This is a callback invoked from the
591 * VFS layer when a lock on which we blocked is removed.
593 * This function doesn't grant the blocked lock instantly, but rather moves
594 * the block to the head of nlm_blocked where it can be picked up by lockd.
597 nlmsvc_notify_blocked(struct file_lock
*fl
)
599 struct nlm_block
*block
;
601 dprintk("lockd: VFS unblock notification for block %p\n", fl
);
602 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
603 if (nlm_compare_locks(&block
->b_call
->a_args
.lock
.fl
, fl
)) {
604 nlmsvc_insert_block(block
, 0);
605 svc_wake_up(block
->b_daemon
);
610 printk(KERN_WARNING
"lockd: notification for unknown block!\n");
613 static int nlmsvc_same_owner(struct file_lock
*fl1
, struct file_lock
*fl2
)
615 return fl1
->fl_owner
== fl2
->fl_owner
&& fl1
->fl_pid
== fl2
->fl_pid
;
618 struct lock_manager_operations nlmsvc_lock_operations
= {
619 .fl_compare_owner
= nlmsvc_same_owner
,
620 .fl_notify
= nlmsvc_notify_blocked
,
621 .fl_grant
= nlmsvc_grant_deferred
,
625 * Try to claim a lock that was previously blocked.
627 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
628 * RPC thread when notifying the client. This seems like overkill...
630 * - we don't want to use a synchronous RPC thread, otherwise
631 * we might find ourselves hanging on a dead portmapper.
632 * - Some lockd implementations (e.g. HP) don't react to
633 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
636 nlmsvc_grant_blocked(struct nlm_block
*block
)
638 struct nlm_file
*file
= block
->b_file
;
639 struct nlm_lock
*lock
= &block
->b_call
->a_args
.lock
;
642 dprintk("lockd: grant blocked lock %p\n", block
);
644 kref_get(&block
->b_count
);
646 /* Unlink block request from list */
647 nlmsvc_unlink_block(block
);
649 /* If b_granted is true this means we've been here before.
650 * Just retry the grant callback, possibly refreshing the RPC
652 if (block
->b_granted
) {
653 nlm_rebind_host(block
->b_host
);
657 /* Try the lock operation again */
658 lock
->fl
.fl_flags
|= FL_SLEEP
;
659 error
= posix_lock_file(file
->f_file
, &lock
->fl
, NULL
);
660 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
666 dprintk("lockd: lock still blocked\n");
667 nlmsvc_insert_block(block
, NLM_NEVER
);
668 nlmsvc_release_block(block
);
671 printk(KERN_WARNING
"lockd: unexpected error %d in %s!\n",
672 -error
, __FUNCTION__
);
673 nlmsvc_insert_block(block
, 10 * HZ
);
674 nlmsvc_release_block(block
);
679 /* Lock was granted by VFS. */
680 dprintk("lockd: GRANTing blocked lock.\n");
681 block
->b_granted
= 1;
683 /* Schedule next grant callback in 30 seconds */
684 nlmsvc_insert_block(block
, 30 * HZ
);
686 /* Call the client */
687 nlm_async_call(block
->b_call
, NLMPROC_GRANTED_MSG
, &nlmsvc_grant_ops
);
691 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
692 * RPC call has succeeded or timed out.
693 * Like all RPC callbacks, it is invoked by the rpciod process, so it
694 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
695 * chain once more in order to have it removed by lockd itself (which can
696 * then sleep on the file semaphore without disrupting e.g. the nfs client).
698 static void nlmsvc_grant_callback(struct rpc_task
*task
, void *data
)
700 struct nlm_rqst
*call
= data
;
701 struct nlm_block
*block
= call
->a_block
;
702 unsigned long timeout
;
704 dprintk("lockd: GRANT_MSG RPC callback\n");
706 /* Technically, we should down the file semaphore here. Since we
707 * move the block towards the head of the queue only, no harm
708 * can be done, though. */
709 if (task
->tk_status
< 0) {
710 /* RPC error: Re-insert for retransmission */
713 /* Call was successful, now wait for client callback */
716 nlmsvc_insert_block(block
, timeout
);
717 svc_wake_up(block
->b_daemon
);
720 static void nlmsvc_grant_release(void *data
)
722 struct nlm_rqst
*call
= data
;
724 nlmsvc_release_block(call
->a_block
);
727 static const struct rpc_call_ops nlmsvc_grant_ops
= {
728 .rpc_call_done
= nlmsvc_grant_callback
,
729 .rpc_release
= nlmsvc_grant_release
,
733 * We received a GRANT_RES callback. Try to find the corresponding
737 nlmsvc_grant_reply(struct nlm_cookie
*cookie
, __be32 status
)
739 struct nlm_block
*block
;
741 dprintk("grant_reply: looking for cookie %x, s=%d \n",
742 *(unsigned int *)(cookie
->data
), status
);
743 if (!(block
= nlmsvc_find_block(cookie
)))
747 if (status
== nlm_lck_denied_grace_period
) {
748 /* Try again in a couple of seconds */
749 nlmsvc_insert_block(block
, 10 * HZ
);
751 /* Lock is now held by client, or has been rejected.
752 * In both cases, the block should be removed. */
753 nlmsvc_unlink_block(block
);
756 nlmsvc_release_block(block
);
759 /* Helper function to handle retry of a deferred block.
760 * If it is a blocking lock, call grant_blocked.
761 * For a non-blocking lock or test lock, revisit the request.
764 retry_deferred_block(struct nlm_block
*block
)
766 if (!(block
->b_flags
& B_GOT_CALLBACK
))
767 block
->b_flags
|= B_TIMED_OUT
;
768 nlmsvc_insert_block(block
, NLM_TIMEOUT
);
769 dprintk("revisit block %p flags %d\n", block
, block
->b_flags
);
770 if (block
->b_deferred_req
) {
771 block
->b_deferred_req
->revisit(block
->b_deferred_req
, 0);
772 block
->b_deferred_req
= NULL
;
777 * Retry all blocked locks that have been notified. This is where lockd
778 * picks up locks that can be granted, or grant notifications that must
782 nlmsvc_retry_blocked(void)
784 unsigned long timeout
= MAX_SCHEDULE_TIMEOUT
;
785 struct nlm_block
*block
;
787 while (!list_empty(&nlm_blocked
)) {
788 block
= list_entry(nlm_blocked
.next
, struct nlm_block
, b_list
);
790 if (block
->b_when
== NLM_NEVER
)
792 if (time_after(block
->b_when
,jiffies
)) {
793 timeout
= block
->b_when
- jiffies
;
797 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
798 block
, block
->b_when
);
799 if (block
->b_flags
& B_QUEUED
) {
800 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
801 block
, block
->b_granted
, block
->b_flags
);
802 retry_deferred_block(block
);
804 nlmsvc_grant_blocked(block
);