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	atomic_inc(&lockowner->count);
 52	return lockowner;
 53}
 54
 55static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
 56{
 57	if (!atomic_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			atomic_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
129	nlmclnt_next_cookie(&argp->cookie);
130	memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
131	lock->caller  = utsname()->nodename;
132	lock->oh.data = req->a_owner;
133	lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
134				(unsigned int)fl->fl_u.nfs_fl.owner->pid,
135				utsname()->nodename);
136	lock->svid = fl->fl_u.nfs_fl.owner->pid;
137	lock->fl.fl_start = fl->fl_start;
138	lock->fl.fl_end = fl->fl_end;
139	lock->fl.fl_type = fl->fl_type;
140}
141
142static void nlmclnt_release_lockargs(struct nlm_rqst *req)
143{
144	BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
145}
146
147/**
148 * nlmclnt_proc - Perform a single client-side lock request
149 * @host: address of a valid nlm_host context representing the NLM server
150 * @cmd: fcntl-style file lock operation to perform
151 * @fl: address of arguments for the lock operation
152 *
153 */
154int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
155{
156	struct nlm_rqst		*call;
157	int			status;
158
159	nlm_get_host(host);
160	call = nlm_alloc_call(host);
161	if (call == NULL)
162		return -ENOMEM;
163
164	nlmclnt_locks_init_private(fl, host);
 
 
 
 
 
165	/* Set up the argument struct */
166	nlmclnt_setlockargs(call, fl);
167
168	if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
169		if (fl->fl_type != F_UNLCK) {
170			call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
171			status = nlmclnt_lock(call, fl);
172		} else
173			status = nlmclnt_unlock(call, fl);
174	} else if (IS_GETLK(cmd))
175		status = nlmclnt_test(call, fl);
176	else
177		status = -EINVAL;
178	fl->fl_ops->fl_release_private(fl);
179	fl->fl_ops = NULL;
180
181	dprintk("lockd: clnt proc returns %d\n", status);
182	return status;
183}
184EXPORT_SYMBOL_GPL(nlmclnt_proc);
185
186/*
187 * Allocate an NLM RPC call struct
188 *
189 * Note: the caller must hold a reference to host. In case of failure,
190 * this reference will be released.
191 */
192struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
193{
194	struct nlm_rqst	*call;
195
196	for(;;) {
197		call = kzalloc(sizeof(*call), GFP_KERNEL);
198		if (call != NULL) {
199			atomic_set(&call->a_count, 1);
200			locks_init_lock(&call->a_args.lock.fl);
201			locks_init_lock(&call->a_res.lock.fl);
202			call->a_host = host;
203			return call;
204		}
205		if (signalled())
206			break;
207		printk("nlm_alloc_call: failed, waiting for memory\n");
208		schedule_timeout_interruptible(5*HZ);
209	}
210	nlmclnt_release_host(host);
211	return NULL;
212}
213
214void nlmclnt_release_call(struct nlm_rqst *call)
215{
216	if (!atomic_dec_and_test(&call->a_count))
217		return;
218	nlmclnt_release_host(call->a_host);
219	nlmclnt_release_lockargs(call);
220	kfree(call);
221}
222
223static void nlmclnt_rpc_release(void *data)
224{
225	nlmclnt_release_call(data);
226}
227
228static int nlm_wait_on_grace(wait_queue_head_t *queue)
229{
230	DEFINE_WAIT(wait);
231	int status = -EINTR;
232
233	prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
234	if (!signalled ()) {
235		schedule_timeout(NLMCLNT_GRACE_WAIT);
236		try_to_freeze();
237		if (!signalled ())
238			status = 0;
239	}
240	finish_wait(queue, &wait);
241	return status;
242}
243
244/*
245 * Generic NLM call
246 */
247static int
248nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
249{
250	struct nlm_host	*host = req->a_host;
251	struct rpc_clnt	*clnt;
252	struct nlm_args	*argp = &req->a_args;
253	struct nlm_res	*resp = &req->a_res;
254	struct rpc_message msg = {
255		.rpc_argp	= argp,
256		.rpc_resp	= resp,
257		.rpc_cred	= cred,
258	};
259	int		status;
260
261	dprintk("lockd: call procedure %d on %s\n",
262			(int)proc, host->h_name);
263
264	do {
265		if (host->h_reclaiming && !argp->reclaim)
266			goto in_grace_period;
267
268		/* If we have no RPC client yet, create one. */
269		if ((clnt = nlm_bind_host(host)) == NULL)
270			return -ENOLCK;
271		msg.rpc_proc = &clnt->cl_procinfo[proc];
272
273		/* Perform the RPC call. If an error occurs, try again */
274		if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
275			dprintk("lockd: rpc_call returned error %d\n", -status);
276			switch (status) {
277			case -EPROTONOSUPPORT:
278				status = -EINVAL;
279				break;
280			case -ECONNREFUSED:
281			case -ETIMEDOUT:
282			case -ENOTCONN:
283				nlm_rebind_host(host);
284				status = -EAGAIN;
285				break;
286			case -ERESTARTSYS:
287				return signalled () ? -EINTR : status;
288			default:
289				break;
290			}
291			break;
292		} else
293		if (resp->status == nlm_lck_denied_grace_period) {
294			dprintk("lockd: server in grace period\n");
295			if (argp->reclaim) {
296				printk(KERN_WARNING
297				     "lockd: spurious grace period reject?!\n");
298				return -ENOLCK;
299			}
300		} else {
301			if (!argp->reclaim) {
302				/* We appear to be out of the grace period */
303				wake_up_all(&host->h_gracewait);
304			}
305			dprintk("lockd: server returns status %d\n",
306				ntohl(resp->status));
307			return 0;	/* Okay, call complete */
308		}
309
310in_grace_period:
311		/*
312		 * The server has rebooted and appears to be in the grace
313		 * period during which locks are only allowed to be
314		 * reclaimed.
315		 * We can only back off and try again later.
316		 */
317		status = nlm_wait_on_grace(&host->h_gracewait);
318	} while (status == 0);
319
320	return status;
321}
322
323/*
324 * Generic NLM call, async version.
325 */
326static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
327{
328	struct nlm_host	*host = req->a_host;
329	struct rpc_clnt	*clnt;
330	struct rpc_task_setup task_setup_data = {
331		.rpc_message = msg,
332		.callback_ops = tk_ops,
333		.callback_data = req,
334		.flags = RPC_TASK_ASYNC,
335	};
336
337	dprintk("lockd: call procedure %d on %s (async)\n",
338			(int)proc, host->h_name);
339
340	/* If we have no RPC client yet, create one. */
341	clnt = nlm_bind_host(host);
342	if (clnt == NULL)
343		goto out_err;
344	msg->rpc_proc = &clnt->cl_procinfo[proc];
345	task_setup_data.rpc_client = clnt;
346
347        /* bootstrap and kick off the async RPC call */
348	return rpc_run_task(&task_setup_data);
349out_err:
350	tk_ops->rpc_release(req);
351	return ERR_PTR(-ENOLCK);
352}
353
354static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
355{
356	struct rpc_task *task;
357
358	task = __nlm_async_call(req, proc, msg, tk_ops);
359	if (IS_ERR(task))
360		return PTR_ERR(task);
361	rpc_put_task(task);
362	return 0;
363}
364
365/*
366 * NLM asynchronous call.
367 */
368int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
369{
370	struct rpc_message msg = {
371		.rpc_argp	= &req->a_args,
372		.rpc_resp	= &req->a_res,
373	};
374	return nlm_do_async_call(req, proc, &msg, tk_ops);
375}
376
377int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
378{
379	struct rpc_message msg = {
380		.rpc_argp	= &req->a_res,
381	};
382	return nlm_do_async_call(req, proc, &msg, tk_ops);
383}
384
385/*
386 * NLM client asynchronous call.
387 *
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
391 *      state.
392 */
393static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
394{
395	struct rpc_message msg = {
396		.rpc_argp	= &req->a_args,
397		.rpc_resp	= &req->a_res,
398		.rpc_cred	= cred,
399	};
400	struct rpc_task *task;
401	int err;
402
403	task = __nlm_async_call(req, proc, &msg, tk_ops);
404	if (IS_ERR(task))
405		return PTR_ERR(task);
406	err = rpc_wait_for_completion_task(task);
407	rpc_put_task(task);
408	return err;
409}
410
411/*
412 * TEST for the presence of a conflicting lock
413 */
414static int
415nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
416{
417	int	status;
418
419	status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
420	if (status < 0)
421		goto out;
422
423	switch (req->a_res.status) {
424		case nlm_granted:
425			fl->fl_type = F_UNLCK;
426			break;
427		case nlm_lck_denied:
428			/*
429			 * Report the conflicting lock back to the application.
430			 */
431			fl->fl_start = req->a_res.lock.fl.fl_start;
432			fl->fl_end = req->a_res.lock.fl.fl_end;
433			fl->fl_type = req->a_res.lock.fl.fl_type;
434			fl->fl_pid = 0;
435			break;
436		default:
437			status = nlm_stat_to_errno(req->a_res.status);
438	}
439out:
440	nlmclnt_release_call(req);
441	return status;
442}
443
444static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
445{
446	spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
447	new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
448	new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
449	list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
450	spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
451}
452
453static void nlmclnt_locks_release_private(struct file_lock *fl)
454{
455	spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
456	list_del(&fl->fl_u.nfs_fl.list);
457	spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
458	nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
459}
460
461static const struct file_lock_operations nlmclnt_lock_ops = {
462	.fl_copy_lock = nlmclnt_locks_copy_lock,
463	.fl_release_private = nlmclnt_locks_release_private,
464};
465
466static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
467{
468	BUG_ON(fl->fl_ops != NULL);
469	fl->fl_u.nfs_fl.state = 0;
470	fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
471	INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
472	fl->fl_ops = &nlmclnt_lock_ops;
473}
474
475static int do_vfs_lock(struct file_lock *fl)
476{
477	int res = 0;
478	switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
479		case FL_POSIX:
480			res = posix_lock_file_wait(fl->fl_file, fl);
481			break;
482		case FL_FLOCK:
483			res = flock_lock_file_wait(fl->fl_file, fl);
484			break;
485		default:
486			BUG();
487	}
488	return res;
489}
490
491/*
492 * LOCK: Try to create a lock
493 *
494 *			Programmer Harassment Alert
495 *
496 * When given a blocking lock request in a sync RPC call, the HPUX lockd
497 * will faithfully return LCK_BLOCKED but never cares to notify us when
498 * the lock could be granted. This way, our local process could hang
499 * around forever waiting for the callback.
500 *
501 *  Solution A:	Implement busy-waiting
502 *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
503 *
504 * For now I am implementing solution A, because I hate the idea of
505 * re-implementing lockd for a third time in two months. The async
506 * calls shouldn't be too hard to do, however.
507 *
508 * This is one of the lovely things about standards in the NFS area:
509 * they're so soft and squishy you can't really blame HP for doing this.
510 */
511static int
512nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
513{
514	struct rpc_cred *cred = nfs_file_cred(fl->fl_file);
515	struct nlm_host	*host = req->a_host;
516	struct nlm_res	*resp = &req->a_res;
517	struct nlm_wait *block = NULL;
518	unsigned char fl_flags = fl->fl_flags;
519	unsigned char fl_type;
520	int status = -ENOLCK;
521
522	if (nsm_monitor(host) < 0)
523		goto out;
524	req->a_args.state = nsm_local_state;
525
526	fl->fl_flags |= FL_ACCESS;
527	status = do_vfs_lock(fl);
528	fl->fl_flags = fl_flags;
529	if (status < 0)
530		goto out;
531
532	block = nlmclnt_prepare_block(host, fl);
533again:
534	/*
535	 * Initialise resp->status to a valid non-zero value,
536	 * since 0 == nlm_lck_granted
537	 */
538	resp->status = nlm_lck_blocked;
539	for(;;) {
540		/* Reboot protection */
541		fl->fl_u.nfs_fl.state = host->h_state;
542		status = nlmclnt_call(cred, req, NLMPROC_LOCK);
543		if (status < 0)
544			break;
545		/* Did a reclaimer thread notify us of a server reboot? */
546		if (resp->status ==  nlm_lck_denied_grace_period)
547			continue;
548		if (resp->status != nlm_lck_blocked)
549			break;
550		/* Wait on an NLM blocking lock */
551		status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
552		if (status < 0)
553			break;
554		if (resp->status != nlm_lck_blocked)
555			break;
556	}
557
558	/* if we were interrupted while blocking, then cancel the lock request
559	 * and exit
560	 */
561	if (resp->status == nlm_lck_blocked) {
562		if (!req->a_args.block)
563			goto out_unlock;
564		if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
565			goto out_unblock;
566	}
567
568	if (resp->status == nlm_granted) {
569		down_read(&host->h_rwsem);
570		/* Check whether or not the server has rebooted */
571		if (fl->fl_u.nfs_fl.state != host->h_state) {
572			up_read(&host->h_rwsem);
573			goto again;
574		}
575		/* Ensure the resulting lock will get added to granted list */
576		fl->fl_flags |= FL_SLEEP;
577		if (do_vfs_lock(fl) < 0)
578			printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
579		up_read(&host->h_rwsem);
580		fl->fl_flags = fl_flags;
581		status = 0;
582	}
583	if (status < 0)
584		goto out_unlock;
585	/*
586	 * EAGAIN doesn't make sense for sleeping locks, and in some
587	 * cases NLM_LCK_DENIED is returned for a permanent error.  So
588	 * turn it into an ENOLCK.
589	 */
590	if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
591		status = -ENOLCK;
592	else
593		status = nlm_stat_to_errno(resp->status);
594out_unblock:
595	nlmclnt_finish_block(block);
596out:
597	nlmclnt_release_call(req);
598	return status;
599out_unlock:
600	/* Fatal error: ensure that we remove the lock altogether */
601	dprintk("lockd: lock attempt ended in fatal error.\n"
602		"       Attempting to unlock.\n");
603	nlmclnt_finish_block(block);
604	fl_type = fl->fl_type;
605	fl->fl_type = F_UNLCK;
606	down_read(&host->h_rwsem);
607	do_vfs_lock(fl);
608	up_read(&host->h_rwsem);
609	fl->fl_type = fl_type;
610	fl->fl_flags = fl_flags;
611	nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
612	return status;
613}
614
615/*
616 * RECLAIM: Try to reclaim a lock
617 */
618int
619nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
 
620{
621	struct nlm_rqst reqst, *req;
622	int		status;
623
624	req = &reqst;
625	memset(req, 0, sizeof(*req));
626	locks_init_lock(&req->a_args.lock.fl);
627	locks_init_lock(&req->a_res.lock.fl);
628	req->a_host  = host;
629	req->a_flags = 0;
630
631	/* Set up the argument struct */
632	nlmclnt_setlockargs(req, fl);
633	req->a_args.reclaim = 1;
634
635	status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
636	if (status >= 0 && req->a_res.status == nlm_granted)
637		return 0;
638
639	printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
640				"(errno %d, status %d)\n", fl->fl_pid,
641				status, ntohl(req->a_res.status));
642
643	/*
644	 * FIXME: This is a serious failure. We can
645	 *
646	 *  a.	Ignore the problem
647	 *  b.	Send the owning process some signal (Linux doesn't have
648	 *	SIGLOST, though...)
649	 *  c.	Retry the operation
650	 *
651	 * Until someone comes up with a simple implementation
652	 * for b or c, I'll choose option a.
653	 */
654
655	return -ENOLCK;
656}
657
658/*
659 * UNLOCK: remove an existing lock
660 */
661static int
662nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
663{
664	struct nlm_host	*host = req->a_host;
665	struct nlm_res	*resp = &req->a_res;
666	int status;
667	unsigned char fl_flags = fl->fl_flags;
668
669	/*
670	 * Note: the server is supposed to either grant us the unlock
671	 * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
672	 * case, we want to unlock.
673	 */
674	fl->fl_flags |= FL_EXISTS;
675	down_read(&host->h_rwsem);
676	status = do_vfs_lock(fl);
677	up_read(&host->h_rwsem);
678	fl->fl_flags = fl_flags;
679	if (status == -ENOENT) {
680		status = 0;
681		goto out;
682	}
683
684	atomic_inc(&req->a_count);
685	status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
686			NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
687	if (status < 0)
688		goto out;
689
690	if (resp->status == nlm_granted)
691		goto out;
692
693	if (resp->status != nlm_lck_denied_nolocks)
694		printk("lockd: unexpected unlock status: %d\n",
695			ntohl(resp->status));
696	/* What to do now? I'm out of my depth... */
697	status = -ENOLCK;
698out:
699	nlmclnt_release_call(req);
700	return status;
701}
702
703static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
704{
705	struct nlm_rqst	*req = data;
706	u32 status = ntohl(req->a_res.status);
707
708	if (RPC_ASSASSINATED(task))
709		goto die;
710
711	if (task->tk_status < 0) {
712		dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
713		switch (task->tk_status) {
714		case -EACCES:
715		case -EIO:
716			goto die;
717		default:
718			goto retry_rebind;
719		}
720	}
721	if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
722		rpc_delay(task, NLMCLNT_GRACE_WAIT);
723		goto retry_unlock;
724	}
725	if (status != NLM_LCK_GRANTED)
726		printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
727die:
728	return;
729 retry_rebind:
730	nlm_rebind_host(req->a_host);
731 retry_unlock:
732	rpc_restart_call(task);
733}
734
735static const struct rpc_call_ops nlmclnt_unlock_ops = {
736	.rpc_call_done = nlmclnt_unlock_callback,
737	.rpc_release = nlmclnt_rpc_release,
738};
739
740/*
741 * Cancel a blocked lock request.
742 * We always use an async RPC call for this in order not to hang a
743 * process that has been Ctrl-C'ed.
744 */
745static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
746{
747	struct nlm_rqst	*req;
748	int status;
749
750	dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
751		"       Attempting to cancel lock.\n");
752
753	req = nlm_alloc_call(nlm_get_host(host));
754	if (!req)
755		return -ENOMEM;
756	req->a_flags = RPC_TASK_ASYNC;
757
758	nlmclnt_setlockargs(req, fl);
759	req->a_args.block = block;
760
761	atomic_inc(&req->a_count);
762	status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
763			NLMPROC_CANCEL, &nlmclnt_cancel_ops);
764	if (status == 0 && req->a_res.status == nlm_lck_denied)
765		status = -ENOLCK;
766	nlmclnt_release_call(req);
767	return status;
768}
769
770static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
771{
772	struct nlm_rqst	*req = data;
773	u32 status = ntohl(req->a_res.status);
774
775	if (RPC_ASSASSINATED(task))
776		goto die;
777
778	if (task->tk_status < 0) {
779		dprintk("lockd: CANCEL call error %d, retrying.\n",
780					task->tk_status);
781		goto retry_cancel;
782	}
783
784	dprintk("lockd: cancel status %u (task %u)\n",
785			status, task->tk_pid);
786
787	switch (status) {
788	case NLM_LCK_GRANTED:
789	case NLM_LCK_DENIED_GRACE_PERIOD:
790	case NLM_LCK_DENIED:
791		/* Everything's good */
792		break;
793	case NLM_LCK_DENIED_NOLOCKS:
794		dprintk("lockd: CANCEL failed (server has no locks)\n");
795		goto retry_cancel;
796	default:
797		printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
798			status);
799	}
800
801die:
802	return;
803
804retry_cancel:
805	/* Don't ever retry more than 3 times */
806	if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
807		goto die;
808	nlm_rebind_host(req->a_host);
809	rpc_restart_call(task);
810	rpc_delay(task, 30 * HZ);
811}
812
813static const struct rpc_call_ops nlmclnt_cancel_ops = {
814	.rpc_call_done = nlmclnt_cancel_callback,
815	.rpc_release = nlmclnt_rpc_release,
816};
817
818/*
819 * Convert an NLM status code to a generic kernel errno
820 */
821static int
822nlm_stat_to_errno(__be32 status)
823{
824	switch(ntohl(status)) {
825	case NLM_LCK_GRANTED:
826		return 0;
827	case NLM_LCK_DENIED:
828		return -EAGAIN;
829	case NLM_LCK_DENIED_NOLOCKS:
830	case NLM_LCK_DENIED_GRACE_PERIOD:
831		return -ENOLCK;
832	case NLM_LCK_BLOCKED:
833		printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
834		return -ENOLCK;
835#ifdef CONFIG_LOCKD_V4
836	case NLM_DEADLCK:
837		return -EDEADLK;
838	case NLM_ROFS:
839		return -EROFS;
840	case NLM_STALE_FH:
841		return -ESTALE;
842	case NLM_FBIG:
843		return -EOVERFLOW;
844	case NLM_FAILED:
845		return -ENOLCK;
846#endif
847	}
848	printk(KERN_NOTICE "lockd: unexpected server status %d\n",
849		 ntohl(status));
850	return -ENOLCK;
851}