1/*
  2 * linux/fs/lockd/clntproc.c
  3 *
  4 * RPC procedures for the client side NLM implementation
  5 *
  6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  7 */
  8
  9#include <linux/module.h>
 10#include <linux/slab.h>
 11#include <linux/types.h>
 12#include <linux/errno.h>
 13#include <linux/fs.h>
 14#include <linux/nfs_fs.h>
 15#include <linux/utsname.h>
 16#include <linux/freezer.h>
 17#include <linux/sunrpc/clnt.h>
 18#include <linux/sunrpc/svc.h>
 19#include <linux/lockd/lockd.h>
 20
 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
 25
 26static int	nlmclnt_test(struct nlm_rqst *, struct file_lock *);
 27static int	nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
 28static int	nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
 29static int	nlm_stat_to_errno(__be32 stat);
 30static void	nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
 31static int	nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
 32
 33static const struct rpc_call_ops nlmclnt_unlock_ops;
 34static const struct rpc_call_ops nlmclnt_cancel_ops;
 35
 36/*
 37 * Cookie counter for NLM requests
 38 */
 39static atomic_t	nlm_cookie = ATOMIC_INIT(0x1234);
 40
 41void nlmclnt_next_cookie(struct nlm_cookie *c)
 42{
 43	u32	cookie = atomic_inc_return(&nlm_cookie);
 44
 45	memcpy(c->data, &cookie, 4);
 46	c->len=4;
 47}
 48
 49static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
 50{
 51	refcount_inc(&lockowner->count);
 52	return lockowner;
 53}
 54
 55static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
 56{
 57	if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
 58		return;
 59	list_del(&lockowner->list);
 60	spin_unlock(&lockowner->host->h_lock);
 61	nlmclnt_release_host(lockowner->host);
 62	kfree(lockowner);
 63}
 64
 65static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
 66{
 67	struct nlm_lockowner *lockowner;
 68	list_for_each_entry(lockowner, &host->h_lockowners, list) {
 69		if (lockowner->pid == pid)
 70			return -EBUSY;
 71	}
 72	return 0;
 73}
 74
 75static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
 76{
 77	uint32_t res;
 78	do {
 79		res = host->h_pidcount++;
 80	} while (nlm_pidbusy(host, res) < 0);
 81	return res;
 82}
 83
 84static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
 85{
 86	struct nlm_lockowner *lockowner;
 87	list_for_each_entry(lockowner, &host->h_lockowners, list) {
 88		if (lockowner->owner != owner)
 89			continue;
 90		return nlm_get_lockowner(lockowner);
 91	}
 92	return NULL;
 93}
 94
 95static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
 96{
 97	struct nlm_lockowner *res, *new = NULL;
 98
 99	spin_lock(&host->h_lock);
100	res = __nlm_find_lockowner(host, owner);
101	if (res == NULL) {
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) {
107			res = new;
108			refcount_set(&new->count, 1);
109			new->owner = owner;
110			new->pid = __nlm_alloc_pid(host);
111			new->host = nlm_get_host(host);
112			list_add(&new->list, &host->h_lockowners);
113			new = NULL;
114		}
115	}
116	spin_unlock(&host->h_lock);
117	kfree(new);
118	return res;
119}
120
121/*
122 * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
123 */
124static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
125{
126	struct nlm_args	*argp = &req->a_args;
127	struct nlm_lock	*lock = &argp->lock;
128	char *nodename = req->a_host->h_rpcclnt->cl_nodename;
129
130	nlmclnt_next_cookie(&argp->cookie);
131	memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
132	lock->caller  = 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				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;
141}
142
143static void nlmclnt_release_lockargs(struct nlm_rqst *req)
144{
145	WARN_ON_ONCE(req->a_args.lock.fl.fl_ops != NULL);
146}
147
148/**
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
153 * @data: address of data to be sent to callback operations
154 *
155 */
156int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data)
157{
158	struct nlm_rqst		*call;
159	int			status;
160	const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops;
161
162	call = nlm_alloc_call(host);
163	if (call == NULL)
164		return -ENOMEM;
165
166	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call)
167		nlmclnt_ops->nlmclnt_alloc_call(data);
168
169	nlmclnt_locks_init_private(fl, host);
170	if (!fl->fl_u.nfs_fl.owner) {
171		/* lockowner allocation has failed */
172		nlmclnt_release_call(call);
173		return -ENOMEM;
174	}
175	/* Set up the argument struct */
176	nlmclnt_setlockargs(call, fl);
177	call->a_callback_data = data;
178
179	if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
180		if (fl->fl_type != F_UNLCK) {
181			call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
182			status = nlmclnt_lock(call, fl);
183		} else
184			status = nlmclnt_unlock(call, fl);
185	} else if (IS_GETLK(cmd))
186		status = nlmclnt_test(call, fl);
187	else
188		status = -EINVAL;
189	fl->fl_ops->fl_release_private(fl);
190	fl->fl_ops = NULL;
191
192	dprintk("lockd: clnt proc returns %d\n", status);
193	return status;
194}
195EXPORT_SYMBOL_GPL(nlmclnt_proc);
196
197/*
198 * Allocate an NLM RPC call struct
199 */
200struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
201{
202	struct nlm_rqst	*call;
203
204	for(;;) {
205		call = kzalloc(sizeof(*call), GFP_KERNEL);
206		if (call != NULL) {
207			refcount_set(&call->a_count, 1);
208			locks_init_lock(&call->a_args.lock.fl);
209			locks_init_lock(&call->a_res.lock.fl);
210			call->a_host = nlm_get_host(host);
211			return call;
212		}
213		if (signalled())
214			break;
215		printk("nlm_alloc_call: failed, waiting for memory\n");
216		schedule_timeout_interruptible(5*HZ);
217	}
218	return NULL;
219}
220
221void nlmclnt_release_call(struct nlm_rqst *call)
222{
223	const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops;
224
225	if (!refcount_dec_and_test(&call->a_count))
226		return;
227	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call)
228		nlmclnt_ops->nlmclnt_release_call(call->a_callback_data);
229	nlmclnt_release_host(call->a_host);
230	nlmclnt_release_lockargs(call);
231	kfree(call);
232}
233
234static void nlmclnt_rpc_release(void *data)
235{
236	nlmclnt_release_call(data);
237}
238
239static int nlm_wait_on_grace(wait_queue_head_t *queue)
240{
241	DEFINE_WAIT(wait);
242	int status = -EINTR;
243
244	prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
245	if (!signalled ()) {
246		schedule_timeout(NLMCLNT_GRACE_WAIT);
247		try_to_freeze();
248		if (!signalled ())
249			status = 0;
250	}
251	finish_wait(queue, &wait);
252	return status;
253}
254
255/*
256 * Generic NLM call
257 */
258static int
259nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
260{
261	struct nlm_host	*host = req->a_host;
262	struct rpc_clnt	*clnt;
263	struct nlm_args	*argp = &req->a_args;
264	struct nlm_res	*resp = &req->a_res;
265	struct rpc_message msg = {
266		.rpc_argp	= argp,
267		.rpc_resp	= resp,
268		.rpc_cred	= cred,
269	};
270	int		status;
271
272	dprintk("lockd: call procedure %d on %s\n",
273			(int)proc, host->h_name);
274
275	do {
276		if (host->h_reclaiming && !argp->reclaim)
277			goto in_grace_period;
278
279		/* If we have no RPC client yet, create one. */
280		if ((clnt = nlm_bind_host(host)) == NULL)
281			return -ENOLCK;
282		msg.rpc_proc = &clnt->cl_procinfo[proc];
283
284		/* Perform the RPC call. If an error occurs, try again */
285		if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
286			dprintk("lockd: rpc_call returned error %d\n", -status);
287			switch (status) {
288			case -EPROTONOSUPPORT:
289				status = -EINVAL;
290				break;
291			case -ECONNREFUSED:
292			case -ETIMEDOUT:
293			case -ENOTCONN:
294				nlm_rebind_host(host);
295				status = -EAGAIN;
296				break;
297			case -ERESTARTSYS:
298				return signalled () ? -EINTR : status;
299			default:
300				break;
301			}
302			break;
303		} else
304		if (resp->status == nlm_lck_denied_grace_period) {
305			dprintk("lockd: server in grace period\n");
306			if (argp->reclaim) {
307				printk(KERN_WARNING
308				     "lockd: spurious grace period reject?!\n");
309				return -ENOLCK;
310			}
311		} else {
312			if (!argp->reclaim) {
313				/* We appear to be out of the grace period */
314				wake_up_all(&host->h_gracewait);
315			}
316			dprintk("lockd: server returns status %d\n",
317				ntohl(resp->status));
318			return 0;	/* Okay, call complete */
319		}
320
321in_grace_period:
322		/*
323		 * The server has rebooted and appears to be in the grace
324		 * period during which locks are only allowed to be
325		 * reclaimed.
326		 * We can only back off and try again later.
327		 */
328		status = nlm_wait_on_grace(&host->h_gracewait);
329	} while (status == 0);
330
331	return status;
332}
333
334/*
335 * Generic NLM call, async version.
336 */
337static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
338{
339	struct nlm_host	*host = req->a_host;
340	struct rpc_clnt	*clnt;
341	struct rpc_task_setup task_setup_data = {
342		.rpc_message = msg,
343		.callback_ops = tk_ops,
344		.callback_data = req,
345		.flags = RPC_TASK_ASYNC,
346	};
347
348	dprintk("lockd: call procedure %d on %s (async)\n",
349			(int)proc, host->h_name);
350
351	/* If we have no RPC client yet, create one. */
352	clnt = nlm_bind_host(host);
353	if (clnt == NULL)
354		goto out_err;
355	msg->rpc_proc = &clnt->cl_procinfo[proc];
356	task_setup_data.rpc_client = clnt;
357
358        /* bootstrap and kick off the async RPC call */
359	return rpc_run_task(&task_setup_data);
360out_err:
361	tk_ops->rpc_release(req);
362	return ERR_PTR(-ENOLCK);
363}
364
365static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
366{
367	struct rpc_task *task;
368
369	task = __nlm_async_call(req, proc, msg, tk_ops);
370	if (IS_ERR(task))
371		return PTR_ERR(task);
372	rpc_put_task(task);
373	return 0;
374}
375
376/*
377 * NLM asynchronous call.
378 */
379int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
380{
381	struct rpc_message msg = {
382		.rpc_argp	= &req->a_args,
383		.rpc_resp	= &req->a_res,
384	};
385	return nlm_do_async_call(req, proc, &msg, tk_ops);
386}
387
388int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
389{
390	struct rpc_message msg = {
391		.rpc_argp	= &req->a_res,
392	};
393	return nlm_do_async_call(req, proc, &msg, tk_ops);
394}
395
396/*
397 * NLM client asynchronous call.
398 *
399 * Note that although the calls are asynchronous, and are therefore
400 *      guaranteed to complete, we still always attempt to wait for
401 *      completion in order to be able to correctly track the lock
402 *      state.
403 */
404static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
405{
406	struct rpc_message msg = {
407		.rpc_argp	= &req->a_args,
408		.rpc_resp	= &req->a_res,
409		.rpc_cred	= cred,
410	};
411	struct rpc_task *task;
412	int err;
413
414	task = __nlm_async_call(req, proc, &msg, tk_ops);
415	if (IS_ERR(task))
416		return PTR_ERR(task);
417	err = rpc_wait_for_completion_task(task);
418	rpc_put_task(task);
419	return err;
420}
421
422/*
423 * TEST for the presence of a conflicting lock
424 */
425static int
426nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
427{
428	int	status;
429
430	status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
431	if (status < 0)
432		goto out;
433
434	switch (req->a_res.status) {
435		case nlm_granted:
436			fl->fl_type = F_UNLCK;
437			break;
438		case nlm_lck_denied:
439			/*
440			 * Report the conflicting lock back to the application.
441			 */
442			fl->fl_start = req->a_res.lock.fl.fl_start;
443			fl->fl_end = req->a_res.lock.fl.fl_end;
444			fl->fl_type = req->a_res.lock.fl.fl_type;
445			fl->fl_pid = 0;
446			break;
447		default:
448			status = nlm_stat_to_errno(req->a_res.status);
449	}
450out:
451	nlmclnt_release_call(req);
452	return status;
453}
454
455static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
456{
457	spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
458	new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
459	new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
460	list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
461	spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
462}
463
464static void nlmclnt_locks_release_private(struct file_lock *fl)
465{
466	spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
467	list_del(&fl->fl_u.nfs_fl.list);
468	spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
469	nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
470}
471
472static const struct file_lock_operations nlmclnt_lock_ops = {
473	.fl_copy_lock = nlmclnt_locks_copy_lock,
474	.fl_release_private = nlmclnt_locks_release_private,
475};
476
477static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
478{
479	fl->fl_u.nfs_fl.state = 0;
480	fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
481	INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
482	fl->fl_ops = &nlmclnt_lock_ops;
483}
484
485static int do_vfs_lock(struct file_lock *fl)
486{
487	return locks_lock_file_wait(fl->fl_file, fl);
488}
489
490/*
491 * LOCK: Try to create a lock
492 *
493 *			Programmer Harassment Alert
494 *
495 * When given a blocking lock request in a sync RPC call, the HPUX lockd
496 * will faithfully return LCK_BLOCKED but never cares to notify us when
497 * the lock could be granted. This way, our local process could hang
498 * around forever waiting for the callback.
499 *
500 *  Solution A:	Implement busy-waiting
501 *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
502 *
503 * For now I am implementing solution A, because I hate the idea of
504 * re-implementing lockd for a third time in two months. The async
505 * calls shouldn't be too hard to do, however.
506 *
507 * This is one of the lovely things about standards in the NFS area:
508 * they're so soft and squishy you can't really blame HP for doing this.
509 */
510static int
511nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
512{
513	struct rpc_cred *cred = nfs_file_cred(fl->fl_file);
514	struct nlm_host	*host = req->a_host;
515	struct nlm_res	*resp = &req->a_res;
516	struct nlm_wait *block = NULL;
517	unsigned char fl_flags = fl->fl_flags;
518	unsigned char fl_type;
519	int status = -ENOLCK;
520
521	if (nsm_monitor(host) < 0)
522		goto out;
523	req->a_args.state = nsm_local_state;
524
525	fl->fl_flags |= FL_ACCESS;
526	status = do_vfs_lock(fl);
527	fl->fl_flags = fl_flags;
528	if (status < 0)
529		goto out;
530
531	block = nlmclnt_prepare_block(host, fl);
532again:
533	/*
534	 * Initialise resp->status to a valid non-zero value,
535	 * since 0 == nlm_lck_granted
536	 */
537	resp->status = nlm_lck_blocked;
538	for(;;) {
539		/* Reboot protection */
540		fl->fl_u.nfs_fl.state = host->h_state;
541		status = nlmclnt_call(cred, req, NLMPROC_LOCK);
542		if (status < 0)
543			break;
544		/* Did a reclaimer thread notify us of a server reboot? */
545		if (resp->status ==  nlm_lck_denied_grace_period)
546			continue;
547		if (resp->status != nlm_lck_blocked)
548			break;
549		/* Wait on an NLM blocking lock */
550		status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
551		if (status < 0)
552			break;
553		if (resp->status != nlm_lck_blocked)
554			break;
555	}
556
557	/* if we were interrupted while blocking, then cancel the lock request
558	 * and exit
559	 */
560	if (resp->status == nlm_lck_blocked) {
561		if (!req->a_args.block)
562			goto out_unlock;
563		if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
564			goto out_unblock;
565	}
566
567	if (resp->status == nlm_granted) {
568		down_read(&host->h_rwsem);
569		/* Check whether or not the server has rebooted */
570		if (fl->fl_u.nfs_fl.state != host->h_state) {
571			up_read(&host->h_rwsem);
572			goto again;
573		}
574		/* Ensure the resulting lock will get added to granted list */
575		fl->fl_flags |= FL_SLEEP;
576		if (do_vfs_lock(fl) < 0)
577			printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
578		up_read(&host->h_rwsem);
579		fl->fl_flags = fl_flags;
580		status = 0;
581	}
582	if (status < 0)
583		goto out_unlock;
584	/*
585	 * EAGAIN doesn't make sense for sleeping locks, and in some
586	 * cases NLM_LCK_DENIED is returned for a permanent error.  So
587	 * turn it into an ENOLCK.
588	 */
589	if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
590		status = -ENOLCK;
591	else
592		status = nlm_stat_to_errno(resp->status);
593out_unblock:
594	nlmclnt_finish_block(block);
595out:
596	nlmclnt_release_call(req);
597	return status;
598out_unlock:
599	/* Fatal error: ensure that we remove the lock altogether */
600	dprintk("lockd: lock attempt ended in fatal error.\n"
601		"       Attempting to unlock.\n");
602	nlmclnt_finish_block(block);
603	fl_type = fl->fl_type;
604	fl->fl_type = F_UNLCK;
605	down_read(&host->h_rwsem);
606	do_vfs_lock(fl);
607	up_read(&host->h_rwsem);
608	fl->fl_type = fl_type;
609	fl->fl_flags = fl_flags;
610	nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
611	return status;
612}
613
614/*
615 * RECLAIM: Try to reclaim a lock
616 */
617int
618nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
619		struct nlm_rqst *req)
620{
621	int		status;
622
623	memset(req, 0, sizeof(*req));
624	locks_init_lock(&req->a_args.lock.fl);
625	locks_init_lock(&req->a_res.lock.fl);
626	req->a_host  = host;
627
628	/* Set up the argument struct */
629	nlmclnt_setlockargs(req, fl);
630	req->a_args.reclaim = 1;
631
632	status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
633	if (status >= 0 && req->a_res.status == nlm_granted)
634		return 0;
635
636	printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
637				"(errno %d, status %d)\n", fl->fl_pid,
638				status, ntohl(req->a_res.status));
639
640	/*
641	 * FIXME: This is a serious failure. We can
642	 *
643	 *  a.	Ignore the problem
644	 *  b.	Send the owning process some signal (Linux doesn't have
645	 *	SIGLOST, though...)
646	 *  c.	Retry the operation
647	 *
648	 * Until someone comes up with a simple implementation
649	 * for b or c, I'll choose option a.
650	 */
651
652	return -ENOLCK;
653}
654
655/*
656 * UNLOCK: remove an existing lock
657 */
658static int
659nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
660{
661	struct nlm_host	*host = req->a_host;
662	struct nlm_res	*resp = &req->a_res;
663	int status;
664	unsigned char fl_flags = fl->fl_flags;
665
666	/*
667	 * Note: the server is supposed to either grant us the unlock
668	 * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
669	 * case, we want to unlock.
670	 */
671	fl->fl_flags |= FL_EXISTS;
672	down_read(&host->h_rwsem);
673	status = do_vfs_lock(fl);
674	up_read(&host->h_rwsem);
675	fl->fl_flags = fl_flags;
676	if (status == -ENOENT) {
677		status = 0;
678		goto out;
679	}
680
681	refcount_inc(&req->a_count);
682	status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
683			NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
684	if (status < 0)
685		goto out;
686
687	if (resp->status == nlm_granted)
688		goto out;
689
690	if (resp->status != nlm_lck_denied_nolocks)
691		printk("lockd: unexpected unlock status: %d\n",
692			ntohl(resp->status));
693	/* What to do now? I'm out of my depth... */
694	status = -ENOLCK;
695out:
696	nlmclnt_release_call(req);
697	return status;
698}
699
700static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data)
701{
702	struct nlm_rqst	*req = data;
703	const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops;
704	bool defer_call = false;
705
706	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare)
707		defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data);
708
709	if (!defer_call)
710		rpc_call_start(task);
711}
712
713static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
714{
715	struct nlm_rqst	*req = data;
716	u32 status = ntohl(req->a_res.status);
717
718	if (RPC_ASSASSINATED(task))
719		goto die;
720
721	if (task->tk_status < 0) {
722		dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
723		switch (task->tk_status) {
724		case -EACCES:
725		case -EIO:
726			goto die;
727		default:
728			goto retry_rebind;
729		}
730	}
731	if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
732		rpc_delay(task, NLMCLNT_GRACE_WAIT);
733		goto retry_unlock;
734	}
735	if (status != NLM_LCK_GRANTED)
736		printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
737die:
738	return;
739 retry_rebind:
740	nlm_rebind_host(req->a_host);
741 retry_unlock:
742	rpc_restart_call(task);
743}
744
745static const struct rpc_call_ops nlmclnt_unlock_ops = {
746	.rpc_call_prepare = nlmclnt_unlock_prepare,
747	.rpc_call_done = nlmclnt_unlock_callback,
748	.rpc_release = nlmclnt_rpc_release,
749};
750
751/*
752 * Cancel a blocked lock request.
753 * We always use an async RPC call for this in order not to hang a
754 * process that has been Ctrl-C'ed.
755 */
756static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
757{
758	struct nlm_rqst	*req;
759	int status;
760
761	dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
762		"       Attempting to cancel lock.\n");
763
764	req = nlm_alloc_call(host);
765	if (!req)
766		return -ENOMEM;
767	req->a_flags = RPC_TASK_ASYNC;
768
769	nlmclnt_setlockargs(req, fl);
770	req->a_args.block = block;
771
772	refcount_inc(&req->a_count);
773	status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
774			NLMPROC_CANCEL, &nlmclnt_cancel_ops);
775	if (status == 0 && req->a_res.status == nlm_lck_denied)
776		status = -ENOLCK;
777	nlmclnt_release_call(req);
778	return status;
779}
780
781static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
782{
783	struct nlm_rqst	*req = data;
784	u32 status = ntohl(req->a_res.status);
785
786	if (RPC_ASSASSINATED(task))
787		goto die;
788
789	if (task->tk_status < 0) {
790		dprintk("lockd: CANCEL call error %d, retrying.\n",
791					task->tk_status);
792		goto retry_cancel;
793	}
794
795	dprintk("lockd: cancel status %u (task %u)\n",
796			status, task->tk_pid);
797
798	switch (status) {
799	case NLM_LCK_GRANTED:
800	case NLM_LCK_DENIED_GRACE_PERIOD:
801	case NLM_LCK_DENIED:
802		/* Everything's good */
803		break;
804	case NLM_LCK_DENIED_NOLOCKS:
805		dprintk("lockd: CANCEL failed (server has no locks)\n");
806		goto retry_cancel;
807	default:
808		printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
809			status);
810	}
811
812die:
813	return;
814
815retry_cancel:
816	/* Don't ever retry more than 3 times */
817	if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
818		goto die;
819	nlm_rebind_host(req->a_host);
820	rpc_restart_call(task);
821	rpc_delay(task, 30 * HZ);
822}
823
824static const struct rpc_call_ops nlmclnt_cancel_ops = {
825	.rpc_call_done = nlmclnt_cancel_callback,
826	.rpc_release = nlmclnt_rpc_release,
827};
828
829/*
830 * Convert an NLM status code to a generic kernel errno
831 */
832static int
833nlm_stat_to_errno(__be32 status)
834{
835	switch(ntohl(status)) {
836	case NLM_LCK_GRANTED:
837		return 0;
838	case NLM_LCK_DENIED:
839		return -EAGAIN;
840	case NLM_LCK_DENIED_NOLOCKS:
841	case NLM_LCK_DENIED_GRACE_PERIOD:
842		return -ENOLCK;
843	case NLM_LCK_BLOCKED:
844		printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
845		return -ENOLCK;
846#ifdef CONFIG_LOCKD_V4
847	case NLM_DEADLCK:
848		return -EDEADLK;
849	case NLM_ROFS:
850		return -EROFS;
851	case NLM_STALE_FH:
852		return -ESTALE;
853	case NLM_FBIG:
854		return -EOVERFLOW;
855	case NLM_FAILED:
856		return -ENOLCK;
857#endif
858	}
859	printk(KERN_NOTICE "lockd: unexpected server status %d\n",
860		 ntohl(status));
861	return -ENOLCK;
862}