2 * linux/fs/lockd/clntproc.c
4 * RPC procedures for the client side NLM implementation
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/errno.h>
13 #include <linux/nfs_fs.h>
14 #include <linux/utsname.h>
15 #include <linux/freezer.h>
16 #include <linux/sunrpc/clnt.h>
17 #include <linux/sunrpc/svc.h>
18 #include <linux/lockd/lockd.h>
19 #include <linux/lockd/sm_inter.h>
21 #define NLMDBG_FACILITY NLMDBG_CLIENT
22 #define NLMCLNT_GRACE_WAIT (5*HZ)
23 #define NLMCLNT_POLL_TIMEOUT (30*HZ)
24 #define NLMCLNT_MAX_RETRIES 3
26 static int nlmclnt_test(struct nlm_rqst *, struct file_lock *);
27 static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
28 static int nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
29 static int nlm_stat_to_errno(__be32 stat);
30 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
31 static int nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
33 static const struct rpc_call_ops nlmclnt_unlock_ops;
34 static const struct rpc_call_ops nlmclnt_cancel_ops;
37 * Cookie counter for NLM requests
39 static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
41 void nlmclnt_next_cookie(struct nlm_cookie *c)
43 u32 cookie = atomic_inc_return(&nlm_cookie);
45 memcpy(c->data, &cookie, 4);
49 static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
51 atomic_inc(&lockowner->count);
55 static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
57 if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
59 list_del(&lockowner->list);
60 spin_unlock(&lockowner->host->h_lock);
61 nlm_release_host(lockowner->host);
65 static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
67 struct nlm_lockowner *lockowner;
68 list_for_each_entry(lockowner, &host->h_lockowners, list) {
69 if (lockowner->pid == pid)
75 static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
79 res = host->h_pidcount++;
80 } while (nlm_pidbusy(host, res) < 0);
84 static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
86 struct nlm_lockowner *lockowner;
87 list_for_each_entry(lockowner, &host->h_lockowners, list) {
88 if (lockowner->owner != owner)
90 return nlm_get_lockowner(lockowner);
95 static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
97 struct nlm_lockowner *res, *new = NULL;
99 spin_lock(&host->h_lock);
100 res = __nlm_find_lockowner(host, owner);
102 spin_unlock(&host->h_lock);
103 new = kmalloc(sizeof(*new), GFP_KERNEL);
104 spin_lock(&host->h_lock);
105 res = __nlm_find_lockowner(host, owner);
106 if (res == NULL && new != NULL) {
108 atomic_set(&new->count, 1);
110 new->pid = __nlm_alloc_pid(host);
111 new->host = nlm_get_host(host);
112 list_add(&new->list, &host->h_lockowners);
116 spin_unlock(&host->h_lock);
122 * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
124 static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
126 struct nlm_args *argp = &req->a_args;
127 struct nlm_lock *lock = &argp->lock;
129 nlmclnt_next_cookie(&argp->cookie);
130 argp->state = nsm_local_state;
131 memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
132 lock->caller = utsname()->nodename;
133 lock->oh.data = req->a_owner;
134 lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
135 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
136 utsname()->nodename);
137 lock->svid = fl->fl_u.nfs_fl.owner->pid;
138 lock->fl.fl_start = fl->fl_start;
139 lock->fl.fl_end = fl->fl_end;
140 lock->fl.fl_type = fl->fl_type;
143 static void nlmclnt_release_lockargs(struct nlm_rqst *req)
145 BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
149 * nlmclnt_proc - Perform a single client-side lock request
150 * @host: address of a valid nlm_host context representing the NLM server
151 * @cmd: fcntl-style file lock operation to perform
152 * @fl: address of arguments for the lock operation
155 int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
157 struct nlm_rqst *call;
161 call = nlm_alloc_call(host);
165 nlmclnt_locks_init_private(fl, host);
166 /* Set up the argument struct */
167 nlmclnt_setlockargs(call, fl);
169 if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
170 if (fl->fl_type != F_UNLCK) {
171 call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
172 status = nlmclnt_lock(call, fl);
174 status = nlmclnt_unlock(call, fl);
175 } else if (IS_GETLK(cmd))
176 status = nlmclnt_test(call, fl);
180 fl->fl_ops->fl_release_private(fl);
183 dprintk("lockd: clnt proc returns %d\n", status);
186 EXPORT_SYMBOL_GPL(nlmclnt_proc);
189 * Allocate an NLM RPC call struct
191 * Note: the caller must hold a reference to host. In case of failure,
192 * this reference will be released.
194 struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
196 struct nlm_rqst *call;
199 call = kzalloc(sizeof(*call), GFP_KERNEL);
201 atomic_set(&call->a_count, 1);
202 locks_init_lock(&call->a_args.lock.fl);
203 locks_init_lock(&call->a_res.lock.fl);
209 printk("nlm_alloc_call: failed, waiting for memory\n");
210 schedule_timeout_interruptible(5*HZ);
212 nlm_release_host(host);
216 void nlm_release_call(struct nlm_rqst *call)
218 if (!atomic_dec_and_test(&call->a_count))
220 nlm_release_host(call->a_host);
221 nlmclnt_release_lockargs(call);
225 static void nlmclnt_rpc_release(void *data)
227 nlm_release_call(data);
230 static int nlm_wait_on_grace(wait_queue_head_t *queue)
235 prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
237 schedule_timeout(NLMCLNT_GRACE_WAIT);
242 finish_wait(queue, &wait);
250 nlmclnt_call(struct nlm_rqst *req, u32 proc)
252 struct nlm_host *host = req->a_host;
253 struct rpc_clnt *clnt;
254 struct nlm_args *argp = &req->a_args;
255 struct nlm_res *resp = &req->a_res;
256 struct rpc_message msg = {
262 dprintk("lockd: call procedure %d on %s\n",
263 (int)proc, host->h_name);
266 if (host->h_reclaiming && !argp->reclaim)
267 goto in_grace_period;
269 /* If we have no RPC client yet, create one. */
270 if ((clnt = nlm_bind_host(host)) == NULL)
272 msg.rpc_proc = &clnt->cl_procinfo[proc];
274 /* Perform the RPC call. If an error occurs, try again */
275 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
276 dprintk("lockd: rpc_call returned error %d\n", -status);
278 case -EPROTONOSUPPORT:
284 nlm_rebind_host(host);
288 return signalled () ? -EINTR : status;
294 if (resp->status == nlm_lck_denied_grace_period) {
295 dprintk("lockd: server in grace period\n");
298 "lockd: spurious grace period reject?!\n");
302 if (!argp->reclaim) {
303 /* We appear to be out of the grace period */
304 wake_up_all(&host->h_gracewait);
306 dprintk("lockd: server returns status %d\n", resp->status);
307 return 0; /* Okay, call complete */
312 * The server has rebooted and appears to be in the grace
313 * period during which locks are only allowed to be
315 * We can only back off and try again later.
317 status = nlm_wait_on_grace(&host->h_gracewait);
318 } while (status == 0);
324 * Generic NLM call, async version.
326 static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
328 struct nlm_host *host = req->a_host;
329 struct rpc_clnt *clnt;
330 struct rpc_task_setup task_setup_data = {
332 .callback_ops = tk_ops,
333 .callback_data = req,
334 .flags = RPC_TASK_ASYNC,
337 dprintk("lockd: call procedure %d on %s (async)\n",
338 (int)proc, host->h_name);
340 /* If we have no RPC client yet, create one. */
341 clnt = nlm_bind_host(host);
344 msg->rpc_proc = &clnt->cl_procinfo[proc];
345 task_setup_data.rpc_client = clnt;
347 /* bootstrap and kick off the async RPC call */
348 return rpc_run_task(&task_setup_data);
350 tk_ops->rpc_release(req);
351 return ERR_PTR(-ENOLCK);
354 static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
356 struct rpc_task *task;
358 task = __nlm_async_call(req, proc, msg, tk_ops);
360 return PTR_ERR(task);
366 * NLM asynchronous call.
368 int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
370 struct rpc_message msg = {
371 .rpc_argp = &req->a_args,
372 .rpc_resp = &req->a_res,
374 return nlm_do_async_call(req, proc, &msg, tk_ops);
377 int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
379 struct rpc_message msg = {
380 .rpc_argp = &req->a_res,
382 return nlm_do_async_call(req, proc, &msg, tk_ops);
386 * NLM client asynchronous call.
388 * Note that although the calls are asynchronous, and are therefore
389 * guaranteed to complete, we still always attempt to wait for
390 * completion in order to be able to correctly track the lock
393 static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
395 struct rpc_message msg = {
396 .rpc_argp = &req->a_args,
397 .rpc_resp = &req->a_res,
399 struct rpc_task *task;
402 task = __nlm_async_call(req, proc, &msg, tk_ops);
404 return PTR_ERR(task);
405 err = rpc_wait_for_completion_task(task);
411 * TEST for the presence of a conflicting lock
414 nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
418 status = nlmclnt_call(req, NLMPROC_TEST);
422 switch (req->a_res.status) {
424 fl->fl_type = F_UNLCK;
428 * Report the conflicting lock back to the application.
430 fl->fl_start = req->a_res.lock.fl.fl_start;
431 fl->fl_end = req->a_res.lock.fl.fl_start;
432 fl->fl_type = req->a_res.lock.fl.fl_type;
436 status = nlm_stat_to_errno(req->a_res.status);
439 nlm_release_call(req);
443 static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
445 new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
446 new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
447 list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
450 static void nlmclnt_locks_release_private(struct file_lock *fl)
452 list_del(&fl->fl_u.nfs_fl.list);
453 nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
456 static struct file_lock_operations nlmclnt_lock_ops = {
457 .fl_copy_lock = nlmclnt_locks_copy_lock,
458 .fl_release_private = nlmclnt_locks_release_private,
461 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
463 BUG_ON(fl->fl_ops != NULL);
464 fl->fl_u.nfs_fl.state = 0;
465 fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
466 INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
467 fl->fl_ops = &nlmclnt_lock_ops;
470 static int do_vfs_lock(struct file_lock *fl)
473 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
475 res = posix_lock_file_wait(fl->fl_file, fl);
478 res = flock_lock_file_wait(fl->fl_file, fl);
487 * LOCK: Try to create a lock
489 * Programmer Harassment Alert
491 * When given a blocking lock request in a sync RPC call, the HPUX lockd
492 * will faithfully return LCK_BLOCKED but never cares to notify us when
493 * the lock could be granted. This way, our local process could hang
494 * around forever waiting for the callback.
496 * Solution A: Implement busy-waiting
497 * Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
499 * For now I am implementing solution A, because I hate the idea of
500 * re-implementing lockd for a third time in two months. The async
501 * calls shouldn't be too hard to do, however.
503 * This is one of the lovely things about standards in the NFS area:
504 * they're so soft and squishy you can't really blame HP for doing this.
507 nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
509 struct nlm_host *host = req->a_host;
510 struct nlm_res *resp = &req->a_res;
511 struct nlm_wait *block = NULL;
512 unsigned char fl_flags = fl->fl_flags;
513 unsigned char fl_type;
514 int status = -ENOLCK;
516 if (nsm_monitor(host) < 0) {
517 printk(KERN_NOTICE "lockd: failed to monitor %s\n",
521 fl->fl_flags |= FL_ACCESS;
522 status = do_vfs_lock(fl);
523 fl->fl_flags = fl_flags;
527 block = nlmclnt_prepare_block(host, fl);
530 * Initialise resp->status to a valid non-zero value,
531 * since 0 == nlm_lck_granted
533 resp->status = nlm_lck_blocked;
535 /* Reboot protection */
536 fl->fl_u.nfs_fl.state = host->h_state;
537 status = nlmclnt_call(req, NLMPROC_LOCK);
540 /* Did a reclaimer thread notify us of a server reboot? */
541 if (resp->status == nlm_lck_denied_grace_period)
543 if (resp->status != nlm_lck_blocked)
545 /* Wait on an NLM blocking lock */
546 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
549 if (resp->status != nlm_lck_blocked)
553 /* if we were interrupted while blocking, then cancel the lock request
556 if (resp->status == nlm_lck_blocked) {
557 if (!req->a_args.block)
559 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
563 if (resp->status == nlm_granted) {
564 down_read(&host->h_rwsem);
565 /* Check whether or not the server has rebooted */
566 if (fl->fl_u.nfs_fl.state != host->h_state) {
567 up_read(&host->h_rwsem);
570 /* Ensure the resulting lock will get added to granted list */
571 fl->fl_flags |= FL_SLEEP;
572 if (do_vfs_lock(fl) < 0)
573 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
574 up_read(&host->h_rwsem);
575 fl->fl_flags = fl_flags;
580 status = nlm_stat_to_errno(resp->status);
582 nlmclnt_finish_block(block);
584 nlm_release_call(req);
587 /* Fatal error: ensure that we remove the lock altogether */
588 dprintk("lockd: lock attempt ended in fatal error.\n"
589 " Attempting to unlock.\n");
590 nlmclnt_finish_block(block);
591 fl_type = fl->fl_type;
592 fl->fl_type = F_UNLCK;
593 down_read(&host->h_rwsem);
595 up_read(&host->h_rwsem);
596 fl->fl_type = fl_type;
597 fl->fl_flags = fl_flags;
598 nlmclnt_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
603 * RECLAIM: Try to reclaim a lock
606 nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
608 struct nlm_rqst reqst, *req;
612 memset(req, 0, sizeof(*req));
613 locks_init_lock(&req->a_args.lock.fl);
614 locks_init_lock(&req->a_res.lock.fl);
618 /* Set up the argument struct */
619 nlmclnt_setlockargs(req, fl);
620 req->a_args.reclaim = 1;
622 if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
623 && req->a_res.status == nlm_granted)
626 printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
627 "(errno %d, status %d)\n", fl->fl_pid,
628 status, ntohl(req->a_res.status));
631 * FIXME: This is a serious failure. We can
633 * a. Ignore the problem
634 * b. Send the owning process some signal (Linux doesn't have
635 * SIGLOST, though...)
636 * c. Retry the operation
638 * Until someone comes up with a simple implementation
639 * for b or c, I'll choose option a.
646 * UNLOCK: remove an existing lock
649 nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
651 struct nlm_host *host = req->a_host;
652 struct nlm_res *resp = &req->a_res;
654 unsigned char fl_flags = fl->fl_flags;
657 * Note: the server is supposed to either grant us the unlock
658 * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
659 * case, we want to unlock.
661 fl->fl_flags |= FL_EXISTS;
662 down_read(&host->h_rwsem);
663 status = do_vfs_lock(fl);
664 up_read(&host->h_rwsem);
665 fl->fl_flags = fl_flags;
666 if (status == -ENOENT) {
671 atomic_inc(&req->a_count);
672 status = nlmclnt_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
676 if (resp->status == nlm_granted)
679 if (resp->status != nlm_lck_denied_nolocks)
680 printk("lockd: unexpected unlock status: %d\n", resp->status);
681 /* What to do now? I'm out of my depth... */
684 nlm_release_call(req);
688 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
690 struct nlm_rqst *req = data;
691 u32 status = ntohl(req->a_res.status);
693 if (RPC_ASSASSINATED(task))
696 if (task->tk_status < 0) {
697 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
700 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
701 rpc_delay(task, NLMCLNT_GRACE_WAIT);
704 if (status != NLM_LCK_GRANTED)
705 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
709 nlm_rebind_host(req->a_host);
711 rpc_restart_call(task);
714 static const struct rpc_call_ops nlmclnt_unlock_ops = {
715 .rpc_call_done = nlmclnt_unlock_callback,
716 .rpc_release = nlmclnt_rpc_release,
720 * Cancel a blocked lock request.
721 * We always use an async RPC call for this in order not to hang a
722 * process that has been Ctrl-C'ed.
724 static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
726 struct nlm_rqst *req;
729 dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
730 " Attempting to cancel lock.\n");
732 req = nlm_alloc_call(nlm_get_host(host));
735 req->a_flags = RPC_TASK_ASYNC;
737 nlmclnt_setlockargs(req, fl);
738 req->a_args.block = block;
740 atomic_inc(&req->a_count);
741 status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
742 if (status == 0 && req->a_res.status == nlm_lck_denied)
744 nlm_release_call(req);
748 static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
750 struct nlm_rqst *req = data;
751 u32 status = ntohl(req->a_res.status);
753 if (RPC_ASSASSINATED(task))
756 if (task->tk_status < 0) {
757 dprintk("lockd: CANCEL call error %d, retrying.\n",
762 dprintk("lockd: cancel status %u (task %u)\n",
763 status, task->tk_pid);
766 case NLM_LCK_GRANTED:
767 case NLM_LCK_DENIED_GRACE_PERIOD:
769 /* Everything's good */
771 case NLM_LCK_DENIED_NOLOCKS:
772 dprintk("lockd: CANCEL failed (server has no locks)\n");
775 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
783 /* Don't ever retry more than 3 times */
784 if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
786 nlm_rebind_host(req->a_host);
787 rpc_restart_call(task);
788 rpc_delay(task, 30 * HZ);
791 static const struct rpc_call_ops nlmclnt_cancel_ops = {
792 .rpc_call_done = nlmclnt_cancel_callback,
793 .rpc_release = nlmclnt_rpc_release,
797 * Convert an NLM status code to a generic kernel errno
800 nlm_stat_to_errno(__be32 status)
802 switch(ntohl(status)) {
803 case NLM_LCK_GRANTED:
807 case NLM_LCK_DENIED_NOLOCKS:
808 case NLM_LCK_DENIED_GRACE_PERIOD:
810 case NLM_LCK_BLOCKED:
811 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
813 #ifdef CONFIG_LOCKD_V4
826 printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);