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.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 * Insert a blocked lock into the global list
60 nlmsvc_insert_block_locked(struct nlm_block
*block
, unsigned long when
)
63 struct list_head
*pos
;
65 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block
, when
);
66 if (list_empty(&block
->b_list
)) {
67 kref_get(&block
->b_count
);
69 list_del_init(&block
->b_list
);
73 if (when
!= NLM_NEVER
) {
74 if ((when
+= jiffies
) == NLM_NEVER
)
76 list_for_each(pos
, &nlm_blocked
) {
77 b
= list_entry(pos
, struct nlm_block
, b_list
);
78 if (time_after(b
->b_when
,when
) || b
->b_when
== NLM_NEVER
)
81 /* On normal exit from the loop, pos == &nlm_blocked,
82 * so we will be adding to the end of the list - good
86 list_add_tail(&block
->b_list
, pos
);
90 static void nlmsvc_insert_block(struct nlm_block
*block
, unsigned long when
)
92 spin_lock(&nlm_blocked_lock
);
93 nlmsvc_insert_block_locked(block
, when
);
94 spin_unlock(&nlm_blocked_lock
);
98 * Remove a block from the global list
101 nlmsvc_remove_block(struct nlm_block
*block
)
103 if (!list_empty(&block
->b_list
)) {
104 spin_lock(&nlm_blocked_lock
);
105 list_del_init(&block
->b_list
);
106 spin_unlock(&nlm_blocked_lock
);
107 nlmsvc_release_block(block
);
112 * Find a block for a given lock
114 static struct nlm_block
*
115 nlmsvc_lookup_block(struct nlm_file
*file
, struct nlm_lock
*lock
)
117 struct nlm_block
*block
;
118 struct file_lock
*fl
;
120 dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
121 file
, lock
->fl
.fl_pid
,
122 (long long)lock
->fl
.fl_start
,
123 (long long)lock
->fl
.fl_end
, lock
->fl
.fl_type
);
124 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
125 fl
= &block
->b_call
->a_args
.lock
.fl
;
126 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
127 block
->b_file
, fl
->fl_pid
,
128 (long long)fl
->fl_start
,
129 (long long)fl
->fl_end
, fl
->fl_type
,
130 nlmdbg_cookie2a(&block
->b_call
->a_args
.cookie
));
131 if (block
->b_file
== file
&& nlm_compare_locks(fl
, &lock
->fl
)) {
132 kref_get(&block
->b_count
);
140 static inline int nlm_cookie_match(struct nlm_cookie
*a
, struct nlm_cookie
*b
)
142 if (a
->len
!= b
->len
)
144 if (memcmp(a
->data
, b
->data
, a
->len
))
150 * Find a block with a given NLM cookie.
152 static inline struct nlm_block
*
153 nlmsvc_find_block(struct nlm_cookie
*cookie
)
155 struct nlm_block
*block
;
157 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
158 if (nlm_cookie_match(&block
->b_call
->a_args
.cookie
,cookie
))
165 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie
), block
);
166 kref_get(&block
->b_count
);
171 * Create a block and initialize it.
173 * Note: we explicitly set the cookie of the grant reply to that of
174 * the blocked lock request. The spec explicitly mentions that the client
175 * should _not_ rely on the callback containing the same cookie as the
176 * request, but (as I found out later) that's because some implementations
177 * do just this. Never mind the standards comittees, they support our
178 * logging industries.
180 * 10 years later: I hope we can safely ignore these old and broken
181 * clients by now. Let's fix this so we can uniquely identify an incoming
182 * GRANTED_RES message by cookie, without having to rely on the client's IP
185 static struct nlm_block
*
186 nlmsvc_create_block(struct svc_rqst
*rqstp
, struct nlm_host
*host
,
187 struct nlm_file
*file
, struct nlm_lock
*lock
,
188 struct nlm_cookie
*cookie
)
190 struct nlm_block
*block
;
191 struct nlm_rqst
*call
= NULL
;
194 call
= nlm_alloc_call(host
);
198 /* Allocate memory for block, and initialize arguments */
199 block
= kzalloc(sizeof(*block
), GFP_KERNEL
);
202 kref_init(&block
->b_count
);
203 INIT_LIST_HEAD(&block
->b_list
);
204 INIT_LIST_HEAD(&block
->b_flist
);
206 if (!nlmsvc_setgrantargs(call
, lock
))
209 /* Set notifier function for VFS, and init args */
210 call
->a_args
.lock
.fl
.fl_flags
|= FL_SLEEP
;
211 call
->a_args
.lock
.fl
.fl_lmops
= &nlmsvc_lock_operations
;
212 nlmclnt_next_cookie(&call
->a_args
.cookie
);
214 dprintk("lockd: created block %p...\n", block
);
216 /* Create and initialize the block */
217 block
->b_daemon
= rqstp
->rq_server
;
218 block
->b_host
= host
;
219 block
->b_file
= file
;
223 /* Add to file's list of blocks */
224 list_add(&block
->b_flist
, &file
->f_blocks
);
226 /* Set up RPC arguments for callback */
227 block
->b_call
= call
;
228 call
->a_flags
= RPC_TASK_ASYNC
;
229 call
->a_block
= block
;
236 nlm_release_call(call
);
242 * It is the caller's responsibility to check whether the file
243 * can be closed hereafter.
245 static int nlmsvc_unlink_block(struct nlm_block
*block
)
248 dprintk("lockd: unlinking block %p...\n", block
);
250 /* Remove block from list */
251 status
= posix_unblock_lock(block
->b_file
->f_file
, &block
->b_call
->a_args
.lock
.fl
);
252 nlmsvc_remove_block(block
);
256 static void nlmsvc_free_block(struct kref
*kref
)
258 struct nlm_block
*block
= container_of(kref
, struct nlm_block
, b_count
);
259 struct nlm_file
*file
= block
->b_file
;
261 dprintk("lockd: freeing block %p...\n", block
);
263 /* Remove block from file's list of blocks */
264 mutex_lock(&file
->f_mutex
);
265 list_del_init(&block
->b_flist
);
266 mutex_unlock(&file
->f_mutex
);
268 nlmsvc_freegrantargs(block
->b_call
);
269 nlm_release_call(block
->b_call
);
270 nlm_release_file(block
->b_file
);
275 static void nlmsvc_release_block(struct nlm_block
*block
)
278 kref_put(&block
->b_count
, nlmsvc_free_block
);
282 * Loop over all blocks and delete blocks held by
285 void nlmsvc_traverse_blocks(struct nlm_host
*host
,
286 struct nlm_file
*file
,
287 nlm_host_match_fn_t match
)
289 struct nlm_block
*block
, *next
;
292 mutex_lock(&file
->f_mutex
);
293 list_for_each_entry_safe(block
, next
, &file
->f_blocks
, b_flist
) {
294 if (!match(block
->b_host
, host
))
296 /* Do not destroy blocks that are not on
297 * the global retry list - why? */
298 if (list_empty(&block
->b_list
))
300 kref_get(&block
->b_count
);
301 mutex_unlock(&file
->f_mutex
);
302 nlmsvc_unlink_block(block
);
303 nlmsvc_release_block(block
);
306 mutex_unlock(&file
->f_mutex
);
310 * Initialize arguments for GRANTED call. The nlm_rqst structure
311 * has been cleared already.
313 static int nlmsvc_setgrantargs(struct nlm_rqst
*call
, struct nlm_lock
*lock
)
315 locks_copy_lock(&call
->a_args
.lock
.fl
, &lock
->fl
);
316 memcpy(&call
->a_args
.lock
.fh
, &lock
->fh
, sizeof(call
->a_args
.lock
.fh
));
317 call
->a_args
.lock
.caller
= utsname()->nodename
;
318 call
->a_args
.lock
.oh
.len
= lock
->oh
.len
;
320 /* set default data area */
321 call
->a_args
.lock
.oh
.data
= call
->a_owner
;
322 call
->a_args
.lock
.svid
= lock
->fl
.fl_pid
;
324 if (lock
->oh
.len
> NLMCLNT_OHSIZE
) {
325 void *data
= kmalloc(lock
->oh
.len
, GFP_KERNEL
);
328 call
->a_args
.lock
.oh
.data
= (u8
*) data
;
331 memcpy(call
->a_args
.lock
.oh
.data
, lock
->oh
.data
, lock
->oh
.len
);
335 static void nlmsvc_freegrantargs(struct nlm_rqst
*call
)
337 if (call
->a_args
.lock
.oh
.data
!= call
->a_owner
)
338 kfree(call
->a_args
.lock
.oh
.data
);
340 locks_release_private(&call
->a_args
.lock
.fl
);
344 * Deferred lock request handling for non-blocking lock
347 nlmsvc_defer_lock_rqst(struct svc_rqst
*rqstp
, struct nlm_block
*block
)
349 __be32 status
= nlm_lck_denied_nolocks
;
351 block
->b_flags
|= B_QUEUED
;
353 nlmsvc_insert_block(block
, NLM_TIMEOUT
);
355 block
->b_cache_req
= &rqstp
->rq_chandle
;
356 if (rqstp
->rq_chandle
.defer
) {
357 block
->b_deferred_req
=
358 rqstp
->rq_chandle
.defer(block
->b_cache_req
);
359 if (block
->b_deferred_req
!= NULL
)
360 status
= nlm_drop_reply
;
362 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
363 block
, block
->b_flags
, ntohl(status
));
369 * Attempt to establish a lock, and if it can't be granted, block it
373 nlmsvc_lock(struct svc_rqst
*rqstp
, struct nlm_file
*file
,
374 struct nlm_host
*host
, struct nlm_lock
*lock
, int wait
,
375 struct nlm_cookie
*cookie
, int reclaim
)
377 struct nlm_block
*block
= NULL
;
381 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
382 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
383 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
384 lock
->fl
.fl_type
, lock
->fl
.fl_pid
,
385 (long long)lock
->fl
.fl_start
,
386 (long long)lock
->fl
.fl_end
,
389 /* Lock file against concurrent access */
390 mutex_lock(&file
->f_mutex
);
391 /* Get existing block (in case client is busy-waiting)
392 * or create new block
394 block
= nlmsvc_lookup_block(file
, lock
);
396 block
= nlmsvc_create_block(rqstp
, host
, file
, lock
, cookie
);
397 ret
= nlm_lck_denied_nolocks
;
400 lock
= &block
->b_call
->a_args
.lock
;
402 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
404 if (block
->b_flags
& B_QUEUED
) {
405 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
406 block
, block
->b_flags
);
407 if (block
->b_granted
) {
408 nlmsvc_unlink_block(block
);
412 if (block
->b_flags
& B_TIMED_OUT
) {
413 nlmsvc_unlink_block(block
);
414 ret
= nlm_lck_denied
;
417 ret
= nlm_drop_reply
;
421 if (locks_in_grace() && !reclaim
) {
422 ret
= nlm_lck_denied_grace_period
;
425 if (reclaim
&& !locks_in_grace()) {
426 ret
= nlm_lck_denied_grace_period
;
431 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
432 error
= vfs_lock_file(file
->f_file
, F_SETLK
, &lock
->fl
, NULL
);
433 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
435 dprintk("lockd: vfs_lock_file returned %d\n", error
);
442 * If this is a blocking request for an
443 * already pending lock request then we need
444 * to put it back on lockd's block list
448 ret
= nlm_lck_denied
;
450 case FILE_LOCK_DEFERRED
:
453 /* Filesystem lock operation is in progress
454 Add it to the queue waiting for callback */
455 ret
= nlmsvc_defer_lock_rqst(rqstp
, block
);
460 default: /* includes ENOLCK */
461 ret
= nlm_lck_denied_nolocks
;
465 ret
= nlm_lck_blocked
;
467 /* Append to list of blocked */
468 nlmsvc_insert_block(block
, NLM_NEVER
);
470 mutex_unlock(&file
->f_mutex
);
471 nlmsvc_release_block(block
);
472 dprintk("lockd: nlmsvc_lock returned %u\n", ret
);
477 * Test for presence of a conflicting lock.
480 nlmsvc_testlock(struct svc_rqst
*rqstp
, struct nlm_file
*file
,
481 struct nlm_host
*host
, struct nlm_lock
*lock
,
482 struct nlm_lock
*conflock
, struct nlm_cookie
*cookie
)
484 struct nlm_block
*block
= NULL
;
488 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
489 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
490 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
492 (long long)lock
->fl
.fl_start
,
493 (long long)lock
->fl
.fl_end
);
495 /* Get existing block (in case client is busy-waiting) */
496 block
= nlmsvc_lookup_block(file
, lock
);
499 struct file_lock
*conf
= kzalloc(sizeof(*conf
), GFP_KERNEL
);
503 block
= nlmsvc_create_block(rqstp
, host
, file
, lock
, cookie
);
510 if (block
->b_flags
& B_QUEUED
) {
511 dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
512 block
, block
->b_flags
, block
->b_fl
);
513 if (block
->b_flags
& B_TIMED_OUT
) {
514 nlmsvc_unlink_block(block
);
515 ret
= nlm_lck_denied
;
518 if (block
->b_flags
& B_GOT_CALLBACK
) {
519 nlmsvc_unlink_block(block
);
520 if (block
->b_fl
!= NULL
521 && block
->b_fl
->fl_type
!= F_UNLCK
) {
522 lock
->fl
= *block
->b_fl
;
529 ret
= nlm_drop_reply
;
533 if (locks_in_grace()) {
534 ret
= nlm_lck_denied_grace_period
;
537 error
= vfs_test_lock(file
->f_file
, &lock
->fl
);
538 if (error
== FILE_LOCK_DEFERRED
) {
539 ret
= nlmsvc_defer_lock_rqst(rqstp
, block
);
543 ret
= nlm_lck_denied_nolocks
;
546 if (lock
->fl
.fl_type
== F_UNLCK
) {
552 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
553 lock
->fl
.fl_type
, (long long)lock
->fl
.fl_start
,
554 (long long)lock
->fl
.fl_end
);
555 conflock
->caller
= "somehost"; /* FIXME */
556 conflock
->len
= strlen(conflock
->caller
);
557 conflock
->oh
.len
= 0; /* don't return OH info */
558 conflock
->svid
= lock
->fl
.fl_pid
;
559 conflock
->fl
.fl_type
= lock
->fl
.fl_type
;
560 conflock
->fl
.fl_start
= lock
->fl
.fl_start
;
561 conflock
->fl
.fl_end
= lock
->fl
.fl_end
;
562 ret
= nlm_lck_denied
;
565 nlmsvc_release_block(block
);
571 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
572 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
573 * afterwards. In this case the block will still be there, and hence
577 nlmsvc_unlock(struct nlm_file
*file
, struct nlm_lock
*lock
)
581 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
582 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
583 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
585 (long long)lock
->fl
.fl_start
,
586 (long long)lock
->fl
.fl_end
);
588 /* First, cancel any lock that might be there */
589 nlmsvc_cancel_blocked(file
, lock
);
591 lock
->fl
.fl_type
= F_UNLCK
;
592 error
= vfs_lock_file(file
->f_file
, F_SETLK
, &lock
->fl
, NULL
);
594 return (error
< 0)? nlm_lck_denied_nolocks
: nlm_granted
;
598 * Cancel a previously blocked request.
600 * A cancel request always overrides any grant that may currently
602 * The calling procedure must check whether the file can be closed.
605 nlmsvc_cancel_blocked(struct nlm_file
*file
, struct nlm_lock
*lock
)
607 struct nlm_block
*block
;
610 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
611 file
->f_file
->f_path
.dentry
->d_inode
->i_sb
->s_id
,
612 file
->f_file
->f_path
.dentry
->d_inode
->i_ino
,
614 (long long)lock
->fl
.fl_start
,
615 (long long)lock
->fl
.fl_end
);
617 if (locks_in_grace())
618 return nlm_lck_denied_grace_period
;
620 mutex_lock(&file
->f_mutex
);
621 block
= nlmsvc_lookup_block(file
, lock
);
622 mutex_unlock(&file
->f_mutex
);
624 vfs_cancel_lock(block
->b_file
->f_file
,
625 &block
->b_call
->a_args
.lock
.fl
);
626 status
= nlmsvc_unlink_block(block
);
627 nlmsvc_release_block(block
);
629 return status
? nlm_lck_denied
: nlm_granted
;
633 * This is a callback from the filesystem for VFS file lock requests.
634 * It will be used if fl_grant is defined and the filesystem can not
635 * respond to the request immediately.
636 * For GETLK request it will copy the reply to the nlm_block.
637 * For SETLK or SETLKW request it will get the local posix lock.
638 * In all cases it will move the block to the head of nlm_blocked q where
639 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
640 * deferred rpc for GETLK and SETLK.
643 nlmsvc_update_deferred_block(struct nlm_block
*block
, struct file_lock
*conf
,
646 block
->b_flags
|= B_GOT_CALLBACK
;
648 block
->b_granted
= 1;
650 block
->b_flags
|= B_TIMED_OUT
;
653 __locks_copy_lock(block
->b_fl
, conf
);
657 static int nlmsvc_grant_deferred(struct file_lock
*fl
, struct file_lock
*conf
,
660 struct nlm_block
*block
;
663 spin_lock(&nlm_blocked_lock
);
664 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
665 if (nlm_compare_locks(&block
->b_call
->a_args
.lock
.fl
, fl
)) {
666 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
667 block
, block
->b_flags
);
668 if (block
->b_flags
& B_QUEUED
) {
669 if (block
->b_flags
& B_TIMED_OUT
) {
673 nlmsvc_update_deferred_block(block
, conf
, result
);
674 } else if (result
== 0)
675 block
->b_granted
= 1;
677 nlmsvc_insert_block_locked(block
, 0);
678 svc_wake_up(block
->b_daemon
);
683 spin_unlock(&nlm_blocked_lock
);
685 printk(KERN_WARNING
"lockd: grant for unknown block\n");
690 * Unblock a blocked lock request. This is a callback invoked from the
691 * VFS layer when a lock on which we blocked is removed.
693 * This function doesn't grant the blocked lock instantly, but rather moves
694 * the block to the head of nlm_blocked where it can be picked up by lockd.
697 nlmsvc_notify_blocked(struct file_lock
*fl
)
699 struct nlm_block
*block
;
701 dprintk("lockd: VFS unblock notification for block %p\n", fl
);
702 spin_lock(&nlm_blocked_lock
);
703 list_for_each_entry(block
, &nlm_blocked
, b_list
) {
704 if (nlm_compare_locks(&block
->b_call
->a_args
.lock
.fl
, fl
)) {
705 nlmsvc_insert_block_locked(block
, 0);
706 spin_unlock(&nlm_blocked_lock
);
707 svc_wake_up(block
->b_daemon
);
711 spin_unlock(&nlm_blocked_lock
);
712 printk(KERN_WARNING
"lockd: notification for unknown block!\n");
715 static int nlmsvc_same_owner(struct file_lock
*fl1
, struct file_lock
*fl2
)
717 return fl1
->fl_owner
== fl2
->fl_owner
&& fl1
->fl_pid
== fl2
->fl_pid
;
720 const struct lock_manager_operations nlmsvc_lock_operations
= {
721 .fl_compare_owner
= nlmsvc_same_owner
,
722 .fl_notify
= nlmsvc_notify_blocked
,
723 .fl_grant
= nlmsvc_grant_deferred
,
727 * Try to claim a lock that was previously blocked.
729 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
730 * RPC thread when notifying the client. This seems like overkill...
732 * - we don't want to use a synchronous RPC thread, otherwise
733 * we might find ourselves hanging on a dead portmapper.
734 * - Some lockd implementations (e.g. HP) don't react to
735 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
738 nlmsvc_grant_blocked(struct nlm_block
*block
)
740 struct nlm_file
*file
= block
->b_file
;
741 struct nlm_lock
*lock
= &block
->b_call
->a_args
.lock
;
744 dprintk("lockd: grant blocked lock %p\n", block
);
746 kref_get(&block
->b_count
);
748 /* Unlink block request from list */
749 nlmsvc_unlink_block(block
);
751 /* If b_granted is true this means we've been here before.
752 * Just retry the grant callback, possibly refreshing the RPC
754 if (block
->b_granted
) {
755 nlm_rebind_host(block
->b_host
);
759 /* Try the lock operation again */
760 lock
->fl
.fl_flags
|= FL_SLEEP
;
761 error
= vfs_lock_file(file
->f_file
, F_SETLK
, &lock
->fl
, NULL
);
762 lock
->fl
.fl_flags
&= ~FL_SLEEP
;
767 case FILE_LOCK_DEFERRED
:
768 dprintk("lockd: lock still blocked error %d\n", error
);
769 nlmsvc_insert_block(block
, NLM_NEVER
);
770 nlmsvc_release_block(block
);
773 printk(KERN_WARNING
"lockd: unexpected error %d in %s!\n",
775 nlmsvc_insert_block(block
, 10 * HZ
);
776 nlmsvc_release_block(block
);
781 /* Lock was granted by VFS. */
782 dprintk("lockd: GRANTing blocked lock.\n");
783 block
->b_granted
= 1;
785 /* keep block on the list, but don't reattempt until the RPC
786 * completes or the submission fails
788 nlmsvc_insert_block(block
, NLM_NEVER
);
790 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
791 * will queue up a new one if this one times out
793 error
= nlm_async_call(block
->b_call
, NLMPROC_GRANTED_MSG
,
796 /* RPC submission failed, wait a bit and retry */
798 nlmsvc_insert_block(block
, 10 * HZ
);
802 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
803 * RPC call has succeeded or timed out.
804 * Like all RPC callbacks, it is invoked by the rpciod process, so it
805 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
806 * chain once more in order to have it removed by lockd itself (which can
807 * then sleep on the file semaphore without disrupting e.g. the nfs client).
809 static void nlmsvc_grant_callback(struct rpc_task
*task
, void *data
)
811 struct nlm_rqst
*call
= data
;
812 struct nlm_block
*block
= call
->a_block
;
813 unsigned long timeout
;
815 dprintk("lockd: GRANT_MSG RPC callback\n");
817 spin_lock(&nlm_blocked_lock
);
818 /* if the block is not on a list at this point then it has
819 * been invalidated. Don't try to requeue it.
821 * FIXME: it's possible that the block is removed from the list
822 * after this check but before the nlmsvc_insert_block. In that
823 * case it will be added back. Perhaps we need better locking
826 if (list_empty(&block
->b_list
))
829 /* Technically, we should down the file semaphore here. Since we
830 * move the block towards the head of the queue only, no harm
831 * can be done, though. */
832 if (task
->tk_status
< 0) {
833 /* RPC error: Re-insert for retransmission */
836 /* Call was successful, now wait for client callback */
839 nlmsvc_insert_block_locked(block
, timeout
);
840 svc_wake_up(block
->b_daemon
);
842 spin_unlock(&nlm_blocked_lock
);
846 * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an
847 * .rpc_release rpc_call_op
849 static void nlmsvc_grant_release(void *data
)
851 struct nlm_rqst
*call
= data
;
852 nlmsvc_release_block(call
->a_block
);
855 static const struct rpc_call_ops nlmsvc_grant_ops
= {
856 .rpc_call_done
= nlmsvc_grant_callback
,
857 .rpc_release
= nlmsvc_grant_release
,
861 * We received a GRANT_RES callback. Try to find the corresponding
865 nlmsvc_grant_reply(struct nlm_cookie
*cookie
, __be32 status
)
867 struct nlm_block
*block
;
869 dprintk("grant_reply: looking for cookie %x, s=%d \n",
870 *(unsigned int *)(cookie
->data
), status
);
871 if (!(block
= nlmsvc_find_block(cookie
)))
875 if (status
== nlm_lck_denied_grace_period
) {
876 /* Try again in a couple of seconds */
877 nlmsvc_insert_block(block
, 10 * HZ
);
879 /* Lock is now held by client, or has been rejected.
880 * In both cases, the block should be removed. */
881 nlmsvc_unlink_block(block
);
884 nlmsvc_release_block(block
);
887 /* Helper function to handle retry of a deferred block.
888 * If it is a blocking lock, call grant_blocked.
889 * For a non-blocking lock or test lock, revisit the request.
892 retry_deferred_block(struct nlm_block
*block
)
894 if (!(block
->b_flags
& B_GOT_CALLBACK
))
895 block
->b_flags
|= B_TIMED_OUT
;
896 nlmsvc_insert_block(block
, NLM_TIMEOUT
);
897 dprintk("revisit block %p flags %d\n", block
, block
->b_flags
);
898 if (block
->b_deferred_req
) {
899 block
->b_deferred_req
->revisit(block
->b_deferred_req
, 0);
900 block
->b_deferred_req
= NULL
;
905 * Retry all blocked locks that have been notified. This is where lockd
906 * picks up locks that can be granted, or grant notifications that must
910 nlmsvc_retry_blocked(void)
912 unsigned long timeout
= MAX_SCHEDULE_TIMEOUT
;
913 struct nlm_block
*block
;
915 while (!list_empty(&nlm_blocked
) && !kthread_should_stop()) {
916 block
= list_entry(nlm_blocked
.next
, struct nlm_block
, b_list
);
918 if (block
->b_when
== NLM_NEVER
)
920 if (time_after(block
->b_when
, jiffies
)) {
921 timeout
= block
->b_when
- jiffies
;
925 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
926 block
, block
->b_when
);
927 if (block
->b_flags
& B_QUEUED
) {
928 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
929 block
, block
->b_granted
, block
->b_flags
);
930 retry_deferred_block(block
);
932 nlmsvc_grant_blocked(block
);