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>
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
);
56 * Insert a blocked lock into the global list
59 nlmsvc_insert_block(struct nlm_block
*block
, unsigned long when
)
62 struct list_head
*pos
;
64 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block
, when
);
65 if (list_empty(&block
->b_list
)) {
66 kref_get(&block
->b_count
);
68 list_del_init(&block
->b_list
);
72 if (when
!= NLM_NEVER
) {
73 if ((when
+= jiffies
) == NLM_NEVER
)
75 list_for_each(pos
, &nlm_blocked
) {
76 b
= list_entry(pos
, struct nlm_block
, b_list
);
77 if (time_after(b
->b_when
,when
) || b
->b_when
== NLM_NEVER
)
80 /* On normal exit from the loop, pos == &nlm_blocked,
81 * so we will be adding to the end of the list - good
85 list_add_tail(&block
->b_list
, pos
);
90 * Remove a block from the global list
93 nlmsvc_remove_block(struct nlm_block
*block
)
95 if (!list_empty(&block
->b_list
)) {
96 list_del_init(&block
->b_list
);
97 nlmsvc_release_block(block
);
102 * Find a block for a given lock
104 static struct nlm_block
*
105 nlmsvc_lookup_block(struct nlm_file
*file
, struct nlm_lock
*lock
)
107 struct nlm_block
*block
;
108 struct file_lock
*fl
;
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 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
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 kref_get(&block
->b_count
);
130 static inline int nlm_cookie_match(struct nlm_cookie
*a
, struct nlm_cookie
*b
)
134 if(memcmp(a
->data
,b
->data
,a
->len
))
140 * Find a block with a given NLM cookie.
142 static inline struct nlm_block
*
143 nlmsvc_find_block(struct nlm_cookie
*cookie
)
145 struct nlm_block
*block
;
147 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
148 if (nlm_cookie_match(&block
->b_call
->a_args
.cookie
,cookie
))
155 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie
), block
);
156 kref_get(&block
->b_count
);
161 * Create a block and initialize it.
163 * Note: we explicitly set the cookie of the grant reply to that of
164 * the blocked lock request. The spec explicitly mentions that the client
165 * should _not_ rely on the callback containing the same cookie as the
166 * request, but (as I found out later) that's because some implementations
167 * do just this. Never mind the standards comittees, they support our
168 * logging industries.
170 * 10 years later: I hope we can safely ignore these old and broken
171 * clients by now. Let's fix this so we can uniquely identify an incoming
172 * GRANTED_RES message by cookie, without having to rely on the client's IP
175 static struct nlm_block
*
176 nlmsvc_create_block(struct svc_rqst
*rqstp
, struct nlm_host
*host
,
177 struct nlm_file
*file
, struct nlm_lock
*lock
,
178 struct nlm_cookie
*cookie
)
180 struct nlm_block
*block
;
181 struct nlm_rqst
*call
= NULL
;
183 call
= nlm_alloc_call(host
);
187 /* Allocate memory for block, and initialize arguments */
188 block
= kzalloc(sizeof(*block
), GFP_KERNEL
);
191 kref_init(&block
->b_count
);
192 INIT_LIST_HEAD(&block
->b_list
);
193 INIT_LIST_HEAD(&block
->b_flist
);
195 if (!nlmsvc_setgrantargs(call
, lock
))
198 /* Set notifier function for VFS, and init args */
199 call
->a_args
.lock
.fl
.fl_flags
|= FL_SLEEP
;
200 call
->a_args
.lock
.fl
.fl_lmops
= &nlmsvc_lock_operations
;
201 nlmclnt_next_cookie(&call
->a_args
.cookie
);
203 dprintk("lockd: created block %p...\n", block
);
205 /* Create and initialize the block */
206 block
->b_daemon
= rqstp
->rq_server
;
207 block
->b_host
= host
;
208 block
->b_file
= file
;
212 /* Add to file's list of blocks */
213 list_add(&block
->b_flist
, &file
->f_blocks
);
215 /* Set up RPC arguments for callback */
216 block
->b_call
= call
;
217 call
->a_flags
= RPC_TASK_ASYNC
;
218 call
->a_block
= block
;
225 nlm_release_call(call
);
231 * It is the caller's responsibility to check whether the file
232 * can be closed hereafter.
234 static int nlmsvc_unlink_block(struct nlm_block
*block
)
237 dprintk("lockd: unlinking block %p...\n", block
);
239 /* Remove block from list */
240 status
= posix_unblock_lock(block
->b_file
->f_file
, &block
->b_call
->a_args
.lock
.fl
);
241 nlmsvc_remove_block(block
);
245 static void nlmsvc_free_block(struct kref
*kref
)
247 struct nlm_block
*block
= container_of(kref
, struct nlm_block
, b_count
);
248 struct nlm_file
*file
= block
->b_file
;
250 dprintk("lockd: freeing block %p...\n", block
);
252 /* Remove block from file's list of blocks */
253 mutex_lock(&file
->f_mutex
);
254 list_del_init(&block
->b_flist
);
255 mutex_unlock(&file
->f_mutex
);
257 nlmsvc_freegrantargs(block
->b_call
);
258 nlm_release_call(block
->b_call
);
259 nlm_release_file(block
->b_file
);
264 static void nlmsvc_release_block(struct nlm_block
*block
)
267 kref_put(&block
->b_count
, nlmsvc_free_block
);
271 * Loop over all blocks and delete blocks held by
274 void nlmsvc_traverse_blocks(struct nlm_host
*host
,
275 struct nlm_file
*file
,
276 nlm_host_match_fn_t match
)
278 struct nlm_block
*block
, *next
;
281 mutex_lock(&file
->f_mutex
);
282 list_for_each_entry_safe(block
, next
, &file
->f_blocks
, b_flist
) {
283 if (!match(block
->b_host
, host
))
285 /* Do not destroy blocks that are not on
286 * the global retry list - why? */
287 if (list_empty(&block
->b_list
))
289 kref_get(&block
->b_count
);
290 mutex_unlock(&file
->f_mutex
);
291 nlmsvc_unlink_block(block
);
292 nlmsvc_release_block(block
);
295 mutex_unlock(&file
->f_mutex
);
299 * Initialize arguments for GRANTED call. The nlm_rqst structure
300 * has been cleared already.
302 static int nlmsvc_setgrantargs(struct nlm_rqst
*call
, struct nlm_lock
*lock
)
304 locks_copy_lock(&call
->a_args
.lock
.fl
, &lock
->fl
);
305 memcpy(&call
->a_args
.lock
.fh
, &lock
->fh
, sizeof(call
->a_args
.lock
.fh
));
306 call
->a_args
.lock
.caller
= utsname()->nodename
;
307 call
->a_args
.lock
.oh
.len
= lock
->oh
.len
;
309 /* set default data area */
310 call
->a_args
.lock
.oh
.data
= call
->a_owner
;
311 call
->a_args
.lock
.svid
= lock
->fl
.fl_pid
;
313 if (lock
->oh
.len
> NLMCLNT_OHSIZE
) {
314 void *data
= kmalloc(lock
->oh
.len
, GFP_KERNEL
);
317 call
->a_args
.lock
.oh
.data
= (u8
*) data
;
320 memcpy(call
->a_args
.lock
.oh
.data
, lock
->oh
.data
, lock
->oh
.len
);
324 static void nlmsvc_freegrantargs(struct nlm_rqst
*call
)
326 if (call
->a_args
.lock
.oh
.data
!= call
->a_owner
)
327 kfree(call
->a_args
.lock
.oh
.data
);
331 * Deferred lock request handling for non-blocking lock
334 nlmsvc_defer_lock_rqst(struct svc_rqst
*rqstp
, struct nlm_block
*block
)
336 __be32 status
= nlm_lck_denied_nolocks
;
338 block
->b_flags
|= B_QUEUED
;
340 nlmsvc_insert_block(block
, NLM_TIMEOUT
);
342 block
->b_cache_req
= &rqstp
->rq_chandle
;
343 if (rqstp
->rq_chandle
.defer
) {
344 block
->b_deferred_req
=
345 rqstp
->rq_chandle
.defer(block
->b_cache_req
);
346 if (block
->b_deferred_req
!= NULL
)
347 status
= nlm_drop_reply
;
349 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
350 block
, block
->b_flags
, ntohl(status
));
356 * Attempt to establish a lock, and if it can't be granted, block it
360 nlmsvc_lock(struct svc_rqst
*rqstp
, struct nlm_file
*file
,
361 struct nlm_lock
*lock
, int wait
, struct nlm_cookie
*cookie
)
363 struct nlm_block
*block
= NULL
;
364 struct nlm_host
*host
;
368 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
369 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
370 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
371 lock
->fl
.fl_type
, lock
->fl
.fl_pid
,
372 (long long)lock
->fl
.fl_start
,
373 (long long)lock
->fl
.fl_end
,
376 /* Create host handle for callback */
377 host
= nlmsvc_lookup_host(rqstp
, lock
->caller
, lock
->len
);
379 return nlm_lck_denied_nolocks
;
381 /* Lock file against concurrent access */
382 mutex_lock(&file
->f_mutex
);
383 /* Get existing block (in case client is busy-waiting)
384 * or create new block
386 block
= nlmsvc_lookup_block(file
, lock
);
388 block
= nlmsvc_create_block(rqstp
, nlm_get_host(host
), file
,
390 ret
= nlm_lck_denied_nolocks
;
393 lock
= &block
->b_call
->a_args
.lock
;
395 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
397 if (block
->b_flags
& B_QUEUED
) {
398 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
399 block
, block
->b_flags
);
400 if (block
->b_granted
) {
401 nlmsvc_unlink_block(block
);
405 if (block
->b_flags
& B_TIMED_OUT
) {
406 nlmsvc_unlink_block(block
);
407 ret
= nlm_lck_denied
;
410 ret
= nlm_drop_reply
;
415 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
416 error
= vfs_lock_file(file
->f_file
, F_SETLK
, &lock
->fl
, NULL
);
417 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
419 dprintk("lockd: vfs_lock_file returned %d\n", error
);
425 ret
= nlm_lck_denied
;
430 /* Filesystem lock operation is in progress
431 Add it to the queue waiting for callback */
432 ret
= nlmsvc_defer_lock_rqst(rqstp
, block
);
437 default: /* includes ENOLCK */
438 ret
= nlm_lck_denied_nolocks
;
442 ret
= nlm_lck_denied
;
446 ret
= nlm_lck_blocked
;
448 /* Append to list of blocked */
449 nlmsvc_insert_block(block
, NLM_NEVER
);
451 mutex_unlock(&file
->f_mutex
);
452 nlmsvc_release_block(block
);
453 nlm_release_host(host
);
454 dprintk("lockd: nlmsvc_lock returned %u\n", ret
);
459 * Test for presence of a conflicting lock.
462 nlmsvc_testlock(struct svc_rqst
*rqstp
, struct nlm_file
*file
,
463 struct nlm_lock
*lock
, struct nlm_lock
*conflock
,
464 struct nlm_cookie
*cookie
)
466 struct nlm_block
*block
= NULL
;
470 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
471 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
472 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
474 (long long)lock
->fl
.fl_start
,
475 (long long)lock
->fl
.fl_end
);
477 /* Get existing block (in case client is busy-waiting) */
478 block
= nlmsvc_lookup_block(file
, lock
);
481 struct file_lock
*conf
= kzalloc(sizeof(*conf
), GFP_KERNEL
);
482 struct nlm_host
*host
;
486 /* Create host handle for callback */
487 host
= nlmsvc_lookup_host(rqstp
, lock
->caller
, lock
->len
);
490 return nlm_lck_denied_nolocks
;
492 block
= nlmsvc_create_block(rqstp
, host
, file
, lock
, cookie
);
499 if (block
->b_flags
& B_QUEUED
) {
500 dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
501 block
, block
->b_flags
, block
->b_fl
);
502 if (block
->b_flags
& B_TIMED_OUT
) {
503 nlmsvc_unlink_block(block
);
504 ret
= nlm_lck_denied
;
507 if (block
->b_flags
& B_GOT_CALLBACK
) {
508 nlmsvc_unlink_block(block
);
509 if (block
->b_fl
!= NULL
510 && block
->b_fl
->fl_type
!= F_UNLCK
) {
511 lock
->fl
= *block
->b_fl
;
518 ret
= nlm_drop_reply
;
522 error
= vfs_test_lock(file
->f_file
, &lock
->fl
);
523 if (error
== -EINPROGRESS
) {
524 ret
= nlmsvc_defer_lock_rqst(rqstp
, block
);
528 ret
= nlm_lck_denied_nolocks
;
531 if (lock
->fl
.fl_type
== F_UNLCK
) {
537 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
538 lock
->fl
.fl_type
, (long long)lock
->fl
.fl_start
,
539 (long long)lock
->fl
.fl_end
);
540 conflock
->caller
= "somehost"; /* FIXME */
541 conflock
->len
= strlen(conflock
->caller
);
542 conflock
->oh
.len
= 0; /* don't return OH info */
543 conflock
->svid
= lock
->fl
.fl_pid
;
544 conflock
->fl
.fl_type
= lock
->fl
.fl_type
;
545 conflock
->fl
.fl_start
= lock
->fl
.fl_start
;
546 conflock
->fl
.fl_end
= lock
->fl
.fl_end
;
547 ret
= nlm_lck_denied
;
550 nlmsvc_release_block(block
);
556 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
557 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
558 * afterwards. In this case the block will still be there, and hence
562 nlmsvc_unlock(struct nlm_file
*file
, struct nlm_lock
*lock
)
566 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
567 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
568 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
570 (long long)lock
->fl
.fl_start
,
571 (long long)lock
->fl
.fl_end
);
573 /* First, cancel any lock that might be there */
574 nlmsvc_cancel_blocked(file
, lock
);
576 lock
->fl
.fl_type
= F_UNLCK
;
577 error
= vfs_lock_file(file
->f_file
, F_SETLK
, &lock
->fl
, NULL
);
579 return (error
< 0)? nlm_lck_denied_nolocks
: nlm_granted
;
583 * Cancel a previously blocked request.
585 * A cancel request always overrides any grant that may currently
587 * The calling procedure must check whether the file can be closed.
590 nlmsvc_cancel_blocked(struct nlm_file
*file
, struct nlm_lock
*lock
)
592 struct nlm_block
*block
;
595 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
596 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
597 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
599 (long long)lock
->fl
.fl_start
,
600 (long long)lock
->fl
.fl_end
);
602 mutex_lock(&file
->f_mutex
);
603 block
= nlmsvc_lookup_block(file
, lock
);
604 mutex_unlock(&file
->f_mutex
);
606 vfs_cancel_lock(block
->b_file
->f_file
,
607 &block
->b_call
->a_args
.lock
.fl
);
608 status
= nlmsvc_unlink_block(block
);
609 nlmsvc_release_block(block
);
611 return status
? nlm_lck_denied
: nlm_granted
;
615 * This is a callback from the filesystem for VFS file lock requests.
616 * It will be used if fl_grant is defined and the filesystem can not
617 * respond to the request immediately.
618 * For GETLK request it will copy the reply to the nlm_block.
619 * For SETLK or SETLKW request it will get the local posix lock.
620 * In all cases it will move the block to the head of nlm_blocked q where
621 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
622 * deferred rpc for GETLK and SETLK.
625 nlmsvc_update_deferred_block(struct nlm_block
*block
, struct file_lock
*conf
,
628 block
->b_flags
|= B_GOT_CALLBACK
;
630 block
->b_granted
= 1;
632 block
->b_flags
|= B_TIMED_OUT
;
635 __locks_copy_lock(block
->b_fl
, conf
);
639 static int nlmsvc_grant_deferred(struct file_lock
*fl
, struct file_lock
*conf
,
642 struct nlm_block
*block
;
646 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
647 if (nlm_compare_locks(&block
->b_call
->a_args
.lock
.fl
, fl
)) {
648 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
649 block
, block
->b_flags
);
650 if (block
->b_flags
& B_QUEUED
) {
651 if (block
->b_flags
& B_TIMED_OUT
) {
655 nlmsvc_update_deferred_block(block
, conf
, result
);
656 } else if (result
== 0)
657 block
->b_granted
= 1;
659 nlmsvc_insert_block(block
, 0);
660 svc_wake_up(block
->b_daemon
);
667 printk(KERN_WARNING
"lockd: grant for unknown block\n");
672 * Unblock a blocked lock request. This is a callback invoked from the
673 * VFS layer when a lock on which we blocked is removed.
675 * This function doesn't grant the blocked lock instantly, but rather moves
676 * the block to the head of nlm_blocked where it can be picked up by lockd.
679 nlmsvc_notify_blocked(struct file_lock
*fl
)
681 struct nlm_block
*block
;
683 dprintk("lockd: VFS unblock notification for block %p\n", fl
);
684 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
685 if (nlm_compare_locks(&block
->b_call
->a_args
.lock
.fl
, fl
)) {
686 nlmsvc_insert_block(block
, 0);
687 svc_wake_up(block
->b_daemon
);
692 printk(KERN_WARNING
"lockd: notification for unknown block!\n");
695 static int nlmsvc_same_owner(struct file_lock
*fl1
, struct file_lock
*fl2
)
697 return fl1
->fl_owner
== fl2
->fl_owner
&& fl1
->fl_pid
== fl2
->fl_pid
;
700 struct lock_manager_operations nlmsvc_lock_operations
= {
701 .fl_compare_owner
= nlmsvc_same_owner
,
702 .fl_notify
= nlmsvc_notify_blocked
,
703 .fl_grant
= nlmsvc_grant_deferred
,
707 * Try to claim a lock that was previously blocked.
709 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
710 * RPC thread when notifying the client. This seems like overkill...
712 * - we don't want to use a synchronous RPC thread, otherwise
713 * we might find ourselves hanging on a dead portmapper.
714 * - Some lockd implementations (e.g. HP) don't react to
715 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
718 nlmsvc_grant_blocked(struct nlm_block
*block
)
720 struct nlm_file
*file
= block
->b_file
;
721 struct nlm_lock
*lock
= &block
->b_call
->a_args
.lock
;
724 dprintk("lockd: grant blocked lock %p\n", block
);
726 kref_get(&block
->b_count
);
728 /* Unlink block request from list */
729 nlmsvc_unlink_block(block
);
731 /* If b_granted is true this means we've been here before.
732 * Just retry the grant callback, possibly refreshing the RPC
734 if (block
->b_granted
) {
735 nlm_rebind_host(block
->b_host
);
739 /* Try the lock operation again */
740 lock
->fl
.fl_flags
|= FL_SLEEP
;
741 error
= vfs_lock_file(file
->f_file
, F_SETLK
, &lock
->fl
, NULL
);
742 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
749 dprintk("lockd: lock still blocked error %d\n", error
);
750 nlmsvc_insert_block(block
, NLM_NEVER
);
751 nlmsvc_release_block(block
);
754 printk(KERN_WARNING
"lockd: unexpected error %d in %s!\n",
756 nlmsvc_insert_block(block
, 10 * HZ
);
757 nlmsvc_release_block(block
);
762 /* Lock was granted by VFS. */
763 dprintk("lockd: GRANTing blocked lock.\n");
764 block
->b_granted
= 1;
766 /* keep block on the list, but don't reattempt until the RPC
767 * completes or the submission fails
769 nlmsvc_insert_block(block
, NLM_NEVER
);
771 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
772 * will queue up a new one if this one times out
774 error
= nlm_async_call(block
->b_call
, NLMPROC_GRANTED_MSG
,
777 /* RPC submission failed, wait a bit and retry */
779 nlmsvc_insert_block(block
, 10 * HZ
);
783 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
784 * RPC call has succeeded or timed out.
785 * Like all RPC callbacks, it is invoked by the rpciod process, so it
786 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
787 * chain once more in order to have it removed by lockd itself (which can
788 * then sleep on the file semaphore without disrupting e.g. the nfs client).
790 static void nlmsvc_grant_callback(struct rpc_task
*task
, void *data
)
792 struct nlm_rqst
*call
= data
;
793 struct nlm_block
*block
= call
->a_block
;
794 unsigned long timeout
;
796 dprintk("lockd: GRANT_MSG RPC callback\n");
799 /* if the block is not on a list at this point then it has
800 * been invalidated. Don't try to requeue it.
802 * FIXME: it's possible that the block is removed from the list
803 * after this check but before the nlmsvc_insert_block. In that
804 * case it will be added back. Perhaps we need better locking
807 if (list_empty(&block
->b_list
))
810 /* Technically, we should down the file semaphore here. Since we
811 * move the block towards the head of the queue only, no harm
812 * can be done, though. */
813 if (task
->tk_status
< 0) {
814 /* RPC error: Re-insert for retransmission */
817 /* Call was successful, now wait for client callback */
820 nlmsvc_insert_block(block
, timeout
);
821 svc_wake_up(block
->b_daemon
);
826 static void nlmsvc_grant_release(void *data
)
828 struct nlm_rqst
*call
= data
;
831 nlmsvc_release_block(call
->a_block
);
835 static const struct rpc_call_ops nlmsvc_grant_ops
= {
836 .rpc_call_done
= nlmsvc_grant_callback
,
837 .rpc_release
= nlmsvc_grant_release
,
841 * We received a GRANT_RES callback. Try to find the corresponding
845 nlmsvc_grant_reply(struct nlm_cookie
*cookie
, __be32 status
)
847 struct nlm_block
*block
;
849 dprintk("grant_reply: looking for cookie %x, s=%d \n",
850 *(unsigned int *)(cookie
->data
), status
);
851 if (!(block
= nlmsvc_find_block(cookie
)))
855 if (status
== nlm_lck_denied_grace_period
) {
856 /* Try again in a couple of seconds */
857 nlmsvc_insert_block(block
, 10 * HZ
);
859 /* Lock is now held by client, or has been rejected.
860 * In both cases, the block should be removed. */
861 nlmsvc_unlink_block(block
);
864 nlmsvc_release_block(block
);
867 /* Helper function to handle retry of a deferred block.
868 * If it is a blocking lock, call grant_blocked.
869 * For a non-blocking lock or test lock, revisit the request.
872 retry_deferred_block(struct nlm_block
*block
)
874 if (!(block
->b_flags
& B_GOT_CALLBACK
))
875 block
->b_flags
|= B_TIMED_OUT
;
876 nlmsvc_insert_block(block
, NLM_TIMEOUT
);
877 dprintk("revisit block %p flags %d\n", block
, block
->b_flags
);
878 if (block
->b_deferred_req
) {
879 block
->b_deferred_req
->revisit(block
->b_deferred_req
, 0);
880 block
->b_deferred_req
= NULL
;
885 * Retry all blocked locks that have been notified. This is where lockd
886 * picks up locks that can be granted, or grant notifications that must
890 nlmsvc_retry_blocked(void)
892 unsigned long timeout
= MAX_SCHEDULE_TIMEOUT
;
893 struct nlm_block
*block
;
895 while (!list_empty(&nlm_blocked
) && !kthread_should_stop()) {
896 block
= list_entry(nlm_blocked
.next
, struct nlm_block
, b_list
);
898 if (block
->b_when
== NLM_NEVER
)
900 if (time_after(block
->b_when
,jiffies
)) {
901 timeout
= block
->b_when
- jiffies
;
905 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
906 block
, block
->b_when
);
907 if (block
->b_flags
& B_QUEUED
) {
908 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
909 block
, block
->b_granted
, block
->b_flags
);
910 retry_deferred_block(block
);
912 nlmsvc_grant_blocked(block
);