clntproc.c 20 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
/*
 * linux/fs/lockd/clntproc.c
 *
 * RPC procedures for the client side NLM implementation
 *
 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/nfs_fs.h>
#include <linux/utsname.h>
#include <linux/smp_lock.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/sm_inter.h>

#define NLMDBG_FACILITY		NLMDBG_CLIENT
#define NLMCLNT_GRACE_WAIT	(5*HZ)
24
#define NLMCLNT_POLL_TIMEOUT	(30*HZ)
25
#define NLMCLNT_MAX_RETRIES	3
Linus Torvalds's avatar
Linus Torvalds committed
26
27
28
29
30
31

static int	nlmclnt_test(struct nlm_rqst *, struct file_lock *);
static int	nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
static int	nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
static int	nlm_stat_to_errno(u32 stat);
static void	nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
32
static int	nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
Linus Torvalds's avatar
Linus Torvalds committed
33

34
35
36
static const struct rpc_call_ops nlmclnt_unlock_ops;
static const struct rpc_call_ops nlmclnt_cancel_ops;

Linus Torvalds's avatar
Linus Torvalds committed
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
/*
 * Cookie counter for NLM requests
 */
static u32	nlm_cookie = 0x1234;

static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
{
	memcpy(c->data, &nlm_cookie, 4);
	memset(c->data+4, 0, 4);
	c->len=4;
	nlm_cookie++;
}

static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
{
	atomic_inc(&lockowner->count);
	return lockowner;
}

static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
{
	if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
		return;
	list_del(&lockowner->list);
	spin_unlock(&lockowner->host->h_lock);
	nlm_release_host(lockowner->host);
	kfree(lockowner);
}

static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
{
	struct nlm_lockowner *lockowner;
	list_for_each_entry(lockowner, &host->h_lockowners, list) {
		if (lockowner->pid == pid)
			return -EBUSY;
	}
	return 0;
}

static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
{
	uint32_t res;
	do {
		res = host->h_pidcount++;
	} while (nlm_pidbusy(host, res) < 0);
	return res;
}

static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
{
	struct nlm_lockowner *lockowner;
	list_for_each_entry(lockowner, &host->h_lockowners, list) {
		if (lockowner->owner != owner)
			continue;
		return nlm_get_lockowner(lockowner);
	}
	return NULL;
}

static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
{
	struct nlm_lockowner *res, *new = NULL;

	spin_lock(&host->h_lock);
	res = __nlm_find_lockowner(host, owner);
	if (res == NULL) {
		spin_unlock(&host->h_lock);
		new = (struct nlm_lockowner *)kmalloc(sizeof(*new), GFP_KERNEL);
		spin_lock(&host->h_lock);
		res = __nlm_find_lockowner(host, owner);
		if (res == NULL && new != NULL) {
			res = new;
			atomic_set(&new->count, 1);
			new->owner = owner;
			new->pid = __nlm_alloc_pid(host);
			new->host = nlm_get_host(host);
			list_add(&new->list, &host->h_lockowners);
			new = NULL;
		}
	}
	spin_unlock(&host->h_lock);
Jesper Juhl's avatar
Jesper Juhl committed
118
	kfree(new);
Linus Torvalds's avatar
Linus Torvalds committed
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
	return res;
}

/*
 * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
 */
static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
{
	struct nlm_args	*argp = &req->a_args;
	struct nlm_lock	*lock = &argp->lock;

	nlmclnt_next_cookie(&argp->cookie);
	argp->state   = nsm_local_state;
	memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
	lock->caller  = system_utsname.nodename;
	lock->oh.data = req->a_owner;
135
136
137
138
	lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
				(unsigned int)fl->fl_u.nfs_fl.owner->pid,
				system_utsname.nodename);
	lock->svid = fl->fl_u.nfs_fl.owner->pid;
Trond Myklebust's avatar
Trond Myklebust committed
139
140
141
	lock->fl.fl_start = fl->fl_start;
	lock->fl.fl_end = fl->fl_end;
	lock->fl.fl_type = fl->fl_type;
Linus Torvalds's avatar
Linus Torvalds committed
142
143
144
145
}

static void nlmclnt_release_lockargs(struct nlm_rqst *req)
{
Trond Myklebust's avatar
Trond Myklebust committed
146
	BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
Linus Torvalds's avatar
Linus Torvalds committed
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
}

/*
 * This is the main entry point for the NLM client.
 */
int
nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
{
	struct nfs_server	*nfssrv = NFS_SERVER(inode);
	struct nlm_host		*host;
	struct nlm_rqst		reqst, *call = &reqst;
	sigset_t		oldset;
	unsigned long		flags;
	int			status, proto, vers;

	vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
	if (NFS_PROTO(inode)->version > 3) {
		printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
		return -ENOLCK;
	}

	/* Retrieve transport protocol from NFS client */
	proto = NFS_CLIENT(inode)->cl_xprt->prot;

	if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
		return -ENOLCK;

	/* Create RPC client handle if not there, and copy soft
	 * and intr flags from NFS client. */
	if (host->h_rpcclnt == NULL) {
		struct rpc_clnt	*clnt;

		/* Bind an rpc client to this host handle (does not
		 * perform a portmapper lookup) */
		if (!(clnt = nlm_bind_host(host))) {
			status = -ENOLCK;
			goto done;
		}
		clnt->cl_softrtry = nfssrv->client->cl_softrtry;
Chuck Lever's avatar
Chuck Lever committed
186
		clnt->cl_intr = nfssrv->client->cl_intr;
Linus Torvalds's avatar
Linus Torvalds committed
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
	}

	/* Keep the old signal mask */
	spin_lock_irqsave(&current->sighand->siglock, flags);
	oldset = current->blocked;

	/* If we're cleaning up locks because the process is exiting,
	 * perform the RPC call asynchronously. */
	if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
	    && fl->fl_type == F_UNLCK
	    && (current->flags & PF_EXITING)) {
		sigfillset(&current->blocked);	/* Mask all signals */
		recalc_sigpending();
		spin_unlock_irqrestore(&current->sighand->siglock, flags);

		call = nlmclnt_alloc_call();
		if (!call) {
			status = -ENOMEM;
			goto out_restore;
		}
		call->a_flags = RPC_TASK_ASYNC;
	} else {
		spin_unlock_irqrestore(&current->sighand->siglock, flags);
		memset(call, 0, sizeof(*call));
		locks_init_lock(&call->a_args.lock.fl);
		locks_init_lock(&call->a_res.lock.fl);
	}
	call->a_host = host;

	nlmclnt_locks_init_private(fl, host);

	/* Set up the argument struct */
	nlmclnt_setlockargs(call, fl);

	if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
		if (fl->fl_type != F_UNLCK) {
			call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
			status = nlmclnt_lock(call, fl);
		} else
			status = nlmclnt_unlock(call, fl);
	} else if (IS_GETLK(cmd))
		status = nlmclnt_test(call, fl);
	else
		status = -EINVAL;

 out_restore:
	spin_lock_irqsave(&current->sighand->siglock, flags);
	current->blocked = oldset;
	recalc_sigpending();
	spin_unlock_irqrestore(&current->sighand->siglock, flags);

done:
	dprintk("lockd: clnt proc returns %d\n", status);
	nlm_release_host(host);
	return status;
}
EXPORT_SYMBOL(nlmclnt_proc);

/*
 * Allocate an NLM RPC call struct
 */
struct nlm_rqst *
nlmclnt_alloc_call(void)
{
	struct nlm_rqst	*call;

253
254
255
	for(;;) {
		call = kzalloc(sizeof(*call), GFP_KERNEL);
		if (call != NULL) {
Linus Torvalds's avatar
Linus Torvalds committed
256
257
258
259
			locks_init_lock(&call->a_args.lock.fl);
			locks_init_lock(&call->a_res.lock.fl);
			return call;
		}
260
261
		if (signalled())
			break;
Linus Torvalds's avatar
Linus Torvalds committed
262
		printk("nlmclnt_alloc_call: failed, waiting for memory\n");
263
		schedule_timeout_interruptible(5*HZ);
Linus Torvalds's avatar
Linus Torvalds committed
264
265
266
267
268
269
270
271
272
273
274
275
	}
	return NULL;
}

static int nlm_wait_on_grace(wait_queue_head_t *queue)
{
	DEFINE_WAIT(wait);
	int status = -EINTR;

	prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
	if (!signalled ()) {
		schedule_timeout(NLMCLNT_GRACE_WAIT);
276
		try_to_freeze();
Linus Torvalds's avatar
Linus Torvalds committed
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
		if (!signalled ())
			status = 0;
	}
	finish_wait(queue, &wait);
	return status;
}

/*
 * Generic NLM call
 */
static int
nlmclnt_call(struct nlm_rqst *req, u32 proc)
{
	struct nlm_host	*host = req->a_host;
	struct rpc_clnt	*clnt;
	struct nlm_args	*argp = &req->a_args;
	struct nlm_res	*resp = &req->a_res;
	struct rpc_message msg = {
		.rpc_argp	= argp,
		.rpc_resp	= resp,
	};
	int		status;

	dprintk("lockd: call procedure %d on %s\n",
			(int)proc, host->h_name);

	do {
		if (host->h_reclaiming && !argp->reclaim)
			goto in_grace_period;

		/* If we have no RPC client yet, create one. */
		if ((clnt = nlm_bind_host(host)) == NULL)
			return -ENOLCK;
		msg.rpc_proc = &clnt->cl_procinfo[proc];

		/* Perform the RPC call. If an error occurs, try again */
		if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
			dprintk("lockd: rpc_call returned error %d\n", -status);
			switch (status) {
			case -EPROTONOSUPPORT:
				status = -EINVAL;
				break;
			case -ECONNREFUSED:
			case -ETIMEDOUT:
			case -ENOTCONN:
				nlm_rebind_host(host);
				status = -EAGAIN;
				break;
			case -ERESTARTSYS:
				return signalled () ? -EINTR : status;
			default:
				break;
			}
			break;
		} else
		if (resp->status == NLM_LCK_DENIED_GRACE_PERIOD) {
			dprintk("lockd: server in grace period\n");
			if (argp->reclaim) {
				printk(KERN_WARNING
				     "lockd: spurious grace period reject?!\n");
				return -ENOLCK;
			}
		} else {
			if (!argp->reclaim) {
				/* We appear to be out of the grace period */
				wake_up_all(&host->h_gracewait);
			}
			dprintk("lockd: server returns status %d\n", resp->status);
			return 0;	/* Okay, call complete */
		}

in_grace_period:
		/*
		 * The server has rebooted and appears to be in the grace
		 * period during which locks are only allowed to be
		 * reclaimed.
		 * We can only back off and try again later.
		 */
		status = nlm_wait_on_grace(&host->h_gracewait);
	} while (status == 0);

	return status;
}

/*
 * Generic NLM call, async version.
 */
364
int nlmsvc_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
Linus Torvalds's avatar
Linus Torvalds committed
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
{
	struct nlm_host	*host = req->a_host;
	struct rpc_clnt	*clnt;
	struct rpc_message msg = {
		.rpc_argp	= &req->a_args,
		.rpc_resp	= &req->a_res,
	};
	int		status;

	dprintk("lockd: call procedure %d on %s (async)\n",
			(int)proc, host->h_name);

	/* If we have no RPC client yet, create one. */
	if ((clnt = nlm_bind_host(host)) == NULL)
		return -ENOLCK;
	msg.rpc_proc = &clnt->cl_procinfo[proc];

        /* bootstrap and kick off the async RPC call */
383
        status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
Linus Torvalds's avatar
Linus Torvalds committed
384
385
386
387

	return status;
}

388
static int nlmclnt_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
Linus Torvalds's avatar
Linus Torvalds committed
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
{
	struct nlm_host	*host = req->a_host;
	struct rpc_clnt	*clnt;
	struct nlm_args	*argp = &req->a_args;
	struct nlm_res	*resp = &req->a_res;
	struct rpc_message msg = {
		.rpc_argp	= argp,
		.rpc_resp	= resp,
	};
	int		status;

	dprintk("lockd: call procedure %d on %s (async)\n",
			(int)proc, host->h_name);

	/* If we have no RPC client yet, create one. */
	if ((clnt = nlm_bind_host(host)) == NULL)
		return -ENOLCK;
	msg.rpc_proc = &clnt->cl_procinfo[proc];

	/* Increment host refcount */
	nlm_get_host(host);
        /* bootstrap and kick off the async RPC call */
411
        status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, tk_ops, req);
Linus Torvalds's avatar
Linus Torvalds committed
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
	if (status < 0)
		nlm_release_host(host);
	return status;
}

/*
 * TEST for the presence of a conflicting lock
 */
static int
nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
{
	int	status;

	status = nlmclnt_call(req, NLMPROC_TEST);
	nlmclnt_release_lockargs(req);
	if (status < 0)
		return status;

	status = req->a_res.status;
	if (status == NLM_LCK_GRANTED) {
		fl->fl_type = F_UNLCK;
	} if (status == NLM_LCK_DENIED) {
		/*
		 * Report the conflicting lock back to the application.
		 */
437
438
439
		fl->fl_start = req->a_res.lock.fl.fl_start;
		fl->fl_end = req->a_res.lock.fl.fl_start;
		fl->fl_type = req->a_res.lock.fl.fl_type;
Linus Torvalds's avatar
Linus Torvalds committed
440
441
442
443
444
445
446
447
448
449
		fl->fl_pid = 0;
	} else {
		return nlm_stat_to_errno(req->a_res.status);
	}

	return 0;
}

static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
{
450
451
452
	new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
	new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
	list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
Linus Torvalds's avatar
Linus Torvalds committed
453
454
455
456
}

static void nlmclnt_locks_release_private(struct file_lock *fl)
{
457
	list_del(&fl->fl_u.nfs_fl.list);
Linus Torvalds's avatar
Linus Torvalds committed
458
459
460
461
462
463
464
465
466
467
468
469
470
	nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
}

static struct file_lock_operations nlmclnt_lock_ops = {
	.fl_copy_lock = nlmclnt_locks_copy_lock,
	.fl_release_private = nlmclnt_locks_release_private,
};

static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
{
	BUG_ON(fl->fl_ops != NULL);
	fl->fl_u.nfs_fl.state = 0;
	fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
471
	INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
Linus Torvalds's avatar
Linus Torvalds committed
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
	fl->fl_ops = &nlmclnt_lock_ops;
}

static void do_vfs_lock(struct file_lock *fl)
{
	int res = 0;
	switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
		case FL_POSIX:
			res = posix_lock_file_wait(fl->fl_file, fl);
			break;
		case FL_FLOCK:
			res = flock_lock_file_wait(fl->fl_file, fl);
			break;
		default:
			BUG();
	}
	if (res < 0)
		printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
				__FUNCTION__);
}

/*
 * LOCK: Try to create a lock
 *
 *			Programmer Harassment Alert
 *
 * When given a blocking lock request in a sync RPC call, the HPUX lockd
 * will faithfully return LCK_BLOCKED but never cares to notify us when
 * the lock could be granted. This way, our local process could hang
 * around forever waiting for the callback.
 *
 *  Solution A:	Implement busy-waiting
 *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
 *
 * For now I am implementing solution A, because I hate the idea of
 * re-implementing lockd for a third time in two months. The async
 * calls shouldn't be too hard to do, however.
 *
 * This is one of the lovely things about standards in the NFS area:
 * they're so soft and squishy you can't really blame HP for doing this.
 */
static int
nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
{
	struct nlm_host	*host = req->a_host;
	struct nlm_res	*resp = &req->a_res;
Trond Myklebust's avatar
Trond Myklebust committed
518
519
	struct nlm_wait *block = NULL;
	int status = -ENOLCK;
Linus Torvalds's avatar
Linus Torvalds committed
520
521
522
523
524
525
526

	if (!host->h_monitored && nsm_monitor(host) < 0) {
		printk(KERN_NOTICE "lockd: failed to monitor %s\n",
					host->h_name);
		goto out;
	}

Trond Myklebust's avatar
Trond Myklebust committed
527
	block = nlmclnt_prepare_block(host, fl);
528
529
530
531
	for(;;) {
		status = nlmclnt_call(req, NLMPROC_LOCK);
		if (status < 0)
			goto out_unblock;
Trond Myklebust's avatar
Trond Myklebust committed
532
		if (!req->a_args.block)
533
534
535
536
537
538
			break;
		/* Did a reclaimer thread notify us of a server reboot? */
		if (resp->status ==  NLM_LCK_DENIED_GRACE_PERIOD)
			continue;
		if (resp->status != NLM_LCK_BLOCKED)
			break;
Trond Myklebust's avatar
Trond Myklebust committed
539
540
541
		/* Wait on an NLM blocking lock */
		status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
		/* if we were interrupted. Send a CANCEL request to the server
542
543
		 * and exit
		 */
Trond Myklebust's avatar
Trond Myklebust committed
544
545
546
547
		if (status < 0)
			goto out_unblock;
		if (resp->status != NLM_LCK_BLOCKED)
			break;
548
	}
Linus Torvalds's avatar
Linus Torvalds committed
549
550
551
552

	if (resp->status == NLM_LCK_GRANTED) {
		fl->fl_u.nfs_fl.state = host->h_state;
		fl->fl_flags |= FL_SLEEP;
553
		/* Ensure the resulting lock will get added to granted list */
Linus Torvalds's avatar
Linus Torvalds committed
554
555
556
		do_vfs_lock(fl);
	}
	status = nlm_stat_to_errno(resp->status);
557
out_unblock:
Trond Myklebust's avatar
Trond Myklebust committed
558
	nlmclnt_finish_block(block);
559
560
	/* Cancel the blocked request if it is still pending */
	if (resp->status == NLM_LCK_BLOCKED)
561
		nlmclnt_cancel(host, req->a_args.block, fl);
Linus Torvalds's avatar
Linus Torvalds committed
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
out:
	nlmclnt_release_lockargs(req);
	return status;
}

/*
 * RECLAIM: Try to reclaim a lock
 */
int
nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
{
	struct nlm_rqst reqst, *req;
	int		status;

	req = &reqst;
	memset(req, 0, sizeof(*req));
	locks_init_lock(&req->a_args.lock.fl);
	locks_init_lock(&req->a_res.lock.fl);
	req->a_host  = host;
	req->a_flags = 0;

	/* Set up the argument struct */
	nlmclnt_setlockargs(req, fl);
	req->a_args.reclaim = 1;

	if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
	 && req->a_res.status == NLM_LCK_GRANTED)
		return 0;

	printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
				"(errno %d, status %d)\n", fl->fl_pid,
				status, req->a_res.status);

	/*
	 * FIXME: This is a serious failure. We can
	 *
	 *  a.	Ignore the problem
	 *  b.	Send the owning process some signal (Linux doesn't have
	 *	SIGLOST, though...)
	 *  c.	Retry the operation
	 *
	 * Until someone comes up with a simple implementation
	 * for b or c, I'll choose option a.
	 */

	return -ENOLCK;
}

/*
 * UNLOCK: remove an existing lock
 */
static int
nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
{
	struct nlm_res	*resp = &req->a_res;
	int		status;

619
620
621
622
623
624
625
	/*
	 * Note: the server is supposed to either grant us the unlock
	 * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
	 * case, we want to unlock.
	 */
	do_vfs_lock(fl);

Linus Torvalds's avatar
Linus Torvalds committed
626
627
	if (req->a_flags & RPC_TASK_ASYNC) {
		status = nlmclnt_async_call(req, NLMPROC_UNLOCK,
628
					&nlmclnt_unlock_ops);
Linus Torvalds's avatar
Linus Torvalds committed
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
		/* Hrmf... Do the unlock early since locks_remove_posix()
		 * really expects us to free the lock synchronously */
		if (status < 0) {
			nlmclnt_release_lockargs(req);
			kfree(req);
		}
		return status;
	}

	status = nlmclnt_call(req, NLMPROC_UNLOCK);
	nlmclnt_release_lockargs(req);
	if (status < 0)
		return status;

	if (resp->status == NLM_LCK_GRANTED)
		return 0;

	if (resp->status != NLM_LCK_DENIED_NOLOCKS)
		printk("lockd: unexpected unlock status: %d\n", resp->status);

	/* What to do now? I'm out of my depth... */

	return -ENOLCK;
}

654
static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
Linus Torvalds's avatar
Linus Torvalds committed
655
{
656
	struct nlm_rqst	*req = data;
Linus Torvalds's avatar
Linus Torvalds committed
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
	int		status = req->a_res.status;

	if (RPC_ASSASSINATED(task))
		goto die;

	if (task->tk_status < 0) {
		dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
		goto retry_rebind;
	}
	if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
		rpc_delay(task, NLMCLNT_GRACE_WAIT);
		goto retry_unlock;
	}
	if (status != NLM_LCK_GRANTED)
		printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
die:
	nlm_release_host(req->a_host);
	nlmclnt_release_lockargs(req);
	kfree(req);
	return;
 retry_rebind:
	nlm_rebind_host(req->a_host);
 retry_unlock:
	rpc_restart_call(task);
}

683
684
685
686
static const struct rpc_call_ops nlmclnt_unlock_ops = {
	.rpc_call_done = nlmclnt_unlock_callback,
};

Linus Torvalds's avatar
Linus Torvalds committed
687
688
689
690
691
/*
 * Cancel a blocked lock request.
 * We always use an async RPC call for this in order not to hang a
 * process that has been Ctrl-C'ed.
 */
692
static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
Linus Torvalds's avatar
Linus Torvalds committed
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
{
	struct nlm_rqst	*req;
	unsigned long	flags;
	sigset_t	oldset;
	int		status;

	/* Block all signals while setting up call */
	spin_lock_irqsave(&current->sighand->siglock, flags);
	oldset = current->blocked;
	sigfillset(&current->blocked);
	recalc_sigpending();
	spin_unlock_irqrestore(&current->sighand->siglock, flags);

	req = nlmclnt_alloc_call();
	if (!req)
		return -ENOMEM;
	req->a_host  = host;
	req->a_flags = RPC_TASK_ASYNC;

	nlmclnt_setlockargs(req, fl);
713
	req->a_args.block = block;
Linus Torvalds's avatar
Linus Torvalds committed
714

715
	status = nlmclnt_async_call(req, NLMPROC_CANCEL, &nlmclnt_cancel_ops);
Linus Torvalds's avatar
Linus Torvalds committed
716
717
718
719
720
721
722
723
724
725
726
727
728
	if (status < 0) {
		nlmclnt_release_lockargs(req);
		kfree(req);
	}

	spin_lock_irqsave(&current->sighand->siglock, flags);
	current->blocked = oldset;
	recalc_sigpending();
	spin_unlock_irqrestore(&current->sighand->siglock, flags);

	return status;
}

729
static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
Linus Torvalds's avatar
Linus Torvalds committed
730
{
731
	struct nlm_rqst	*req = data;
Linus Torvalds's avatar
Linus Torvalds committed
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747

	if (RPC_ASSASSINATED(task))
		goto die;

	if (task->tk_status < 0) {
		dprintk("lockd: CANCEL call error %d, retrying.\n",
					task->tk_status);
		goto retry_cancel;
	}

	dprintk("lockd: cancel status %d (task %d)\n",
			req->a_res.status, task->tk_pid);

	switch (req->a_res.status) {
	case NLM_LCK_GRANTED:
	case NLM_LCK_DENIED_GRACE_PERIOD:
748
	case NLM_LCK_DENIED:
Linus Torvalds's avatar
Linus Torvalds committed
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
		/* Everything's good */
		break;
	case NLM_LCK_DENIED_NOLOCKS:
		dprintk("lockd: CANCEL failed (server has no locks)\n");
		goto retry_cancel;
	default:
		printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
			req->a_res.status);
	}

die:
	nlm_release_host(req->a_host);
	nlmclnt_release_lockargs(req);
	kfree(req);
	return;

retry_cancel:
766
767
768
	/* Don't ever retry more than 3 times */
	if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
		goto die;
Linus Torvalds's avatar
Linus Torvalds committed
769
770
771
772
773
	nlm_rebind_host(req->a_host);
	rpc_restart_call(task);
	rpc_delay(task, 30 * HZ);
}

774
775
776
777
static const struct rpc_call_ops nlmclnt_cancel_ops = {
	.rpc_call_done = nlmclnt_cancel_callback,
};

Linus Torvalds's avatar
Linus Torvalds committed
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
/*
 * Convert an NLM status code to a generic kernel errno
 */
static int
nlm_stat_to_errno(u32 status)
{
	switch(status) {
	case NLM_LCK_GRANTED:
		return 0;
	case NLM_LCK_DENIED:
		return -EAGAIN;
	case NLM_LCK_DENIED_NOLOCKS:
	case NLM_LCK_DENIED_GRACE_PERIOD:
		return -ENOLCK;
	case NLM_LCK_BLOCKED:
		printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
		return -ENOLCK;
#ifdef CONFIG_LOCKD_V4
	case NLM_DEADLCK:
		return -EDEADLK;
	case NLM_ROFS:
		return -EROFS;
	case NLM_STALE_FH:
		return -ESTALE;
	case NLM_FBIG:
		return -EOVERFLOW;
	case NLM_FAILED:
		return -ENOLCK;
#endif
	}
	printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
	return -ENOLCK;
}