summaryrefslogtreecommitdiff
path: root/fs/afs/rotate.c
blob: ef7fe70777be617daddfe8b5266adcc2ced53255 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
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
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
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
186
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
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
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
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
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
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
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
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
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
619
620
621
622
623
624
625
626
627
628
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
654
655
656
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
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
// SPDX-License-Identifier: GPL-2.0-or-later
/* Handle fileserver selection and rotation.
 *
 * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/sched/signal.h>
#include "internal.h"
#include "afs_fs.h"
#include "protocol_uae.h"

void afs_clear_server_states(struct afs_operation *op)
{
	unsigned int i;

	if (op->server_states) {
		for (i = 0; i < op->server_list->nr_servers; i++)
			afs_put_endpoint_state(op->server_states[i].endpoint_state,
					       afs_estate_trace_put_server_state);
		kfree(op->server_states);
	}
}

/*
 * Begin iteration through a server list, starting with the vnode's last used
 * server if possible, or the last recorded good server if not.
 */
static bool afs_start_fs_iteration(struct afs_operation *op,
				   struct afs_vnode *vnode)
{
	struct afs_server *server;
	void *cb_server;
	int i;

	trace_afs_rotate(op, afs_rotate_trace_start, 0);

	read_lock(&op->volume->servers_lock);
	op->server_list = afs_get_serverlist(
		rcu_dereference_protected(op->volume->servers,
					  lockdep_is_held(&op->volume->servers_lock)));
	read_unlock(&op->volume->servers_lock);

	op->server_states = kcalloc(op->server_list->nr_servers, sizeof(op->server_states[0]),
				    GFP_KERNEL);
	if (!op->server_states) {
		afs_op_nomem(op);
		trace_afs_rotate(op, afs_rotate_trace_nomem, 0);
		return false;
	}

	rcu_read_lock();
	for (i = 0; i < op->server_list->nr_servers; i++) {
		struct afs_endpoint_state *estate;
		struct afs_server_state *s = &op->server_states[i];

		server = op->server_list->servers[i].server;
		estate = rcu_dereference(server->endpoint_state);
		s->endpoint_state = afs_get_endpoint_state(estate,
							   afs_estate_trace_get_server_state);
		s->probe_seq = estate->probe_seq;
		s->untried_addrs = (1UL << estate->addresses->nr_addrs) - 1;
		init_waitqueue_entry(&s->probe_waiter, current);
		afs_get_address_preferences(op->net, estate->addresses);
	}
	rcu_read_unlock();


	op->untried_servers = (1UL << op->server_list->nr_servers) - 1;
	op->server_index = -1;

	cb_server = vnode->cb_server;
	if (cb_server) {
		/* See if the vnode's preferred record is still available */
		for (i = 0; i < op->server_list->nr_servers; i++) {
			server = op->server_list->servers[i].server;
			if (server == cb_server) {
				op->server_index = i;
				goto found_interest;
			}
		}

		/* If we have a lock outstanding on a server that's no longer
		 * serving this vnode, then we can't switch to another server
		 * and have to return an error.
		 */
		if (op->flags & AFS_OPERATION_CUR_ONLY) {
			afs_op_set_error(op, -ESTALE);
			trace_afs_rotate(op, afs_rotate_trace_stale_lock, 0);
			return false;
		}

		/* Note that the callback promise is effectively broken */
		write_seqlock(&vnode->cb_lock);
		ASSERTCMP(cb_server, ==, vnode->cb_server);
		vnode->cb_server = NULL;
		if (atomic64_xchg(&vnode->cb_expires_at, AFS_NO_CB_PROMISE) != AFS_NO_CB_PROMISE)
			vnode->cb_break++;
		write_sequnlock(&vnode->cb_lock);
	}

found_interest:
	return true;
}

/*
 * Post volume busy note.
 */
static void afs_busy(struct afs_volume *volume, u32 abort_code)
{
	const char *m;

	switch (abort_code) {
	case VOFFLINE:		m = "offline";		break;
	case VRESTARTING:	m = "restarting";	break;
	case VSALVAGING:	m = "being salvaged";	break;
	default:		m = "busy";		break;
	}

	pr_notice("kAFS: Volume %llu '%s' is %s\n", volume->vid, volume->name, m);
}

/*
 * Sleep and retry the operation to the same fileserver.
 */
static bool afs_sleep_and_retry(struct afs_operation *op)
{
	trace_afs_rotate(op, afs_rotate_trace_busy_sleep, 0);
	if (!(op->flags & AFS_OPERATION_UNINTR)) {
		msleep_interruptible(1000);
		if (signal_pending(current)) {
			afs_op_set_error(op, -ERESTARTSYS);
			return false;
		}
	} else {
		msleep(1000);
	}

	return true;
}

/*
 * Select the fileserver to use.  May be called multiple times to rotate
 * through the fileservers.
 */
bool afs_select_fileserver(struct afs_operation *op)
{
	struct afs_addr_list *alist;
	struct afs_server *server;
	struct afs_vnode *vnode = op->file[0].vnode;
	unsigned long set, failed;
	s32 abort_code = op->call_abort_code;
	int best_prio = 0;
	int error = op->call_error, addr_index, i, j;

	op->nr_iterations++;

	_enter("OP=%x+%x,%llx,%u{%lx},%u{%lx},%d,%d",
	       op->debug_id, op->nr_iterations, op->volume->vid,
	       op->server_index, op->untried_servers,
	       op->addr_index, op->addr_tried,
	       error, abort_code);

	if (op->flags & AFS_OPERATION_STOP) {
		trace_afs_rotate(op, afs_rotate_trace_stopped, 0);
		_leave(" = f [stopped]");
		return false;
	}

	if (op->nr_iterations == 0)
		goto start;

	WRITE_ONCE(op->estate->addresses->addrs[op->addr_index].last_error, error);
	trace_afs_rotate(op, afs_rotate_trace_iter, op->call_error);

	/* Evaluate the result of the previous operation, if there was one. */
	switch (op->call_error) {
	case 0:
		op->cumul_error.responded = true;

		/* We succeeded, but we may need to redo the op from another
		 * server if we're looking at a set of RO volumes where some of
		 * the servers have not yet been brought up to date lest we
		 * regress the data.  We only switch to the new version once
		 * >=50% of the servers are updated.
		 */
		error = afs_update_volume_state(op);
		if (error != 0) {
			if (error == 1) {
				afs_sleep_and_retry(op);
				goto restart_from_beginning;
			}
			afs_op_set_error(op, error);
			goto failed;
		}
		fallthrough;
	default:
		/* Success or local failure.  Stop. */
		afs_op_set_error(op, error);
		op->flags |= AFS_OPERATION_STOP;
		trace_afs_rotate(op, afs_rotate_trace_stop, error);
		_leave(" = f [okay/local %d]", error);
		return false;

	case -ECONNABORTED:
		/* The far side rejected the operation on some grounds.  This
		 * might involve the server being busy or the volume having been moved.
		 *
		 * Note that various V* errors should not be sent to a cache manager
		 * by a fileserver as they should be translated to more modern UAE*
		 * errors instead.  IBM AFS and OpenAFS fileservers, however, do leak
		 * these abort codes.
		 */
		trace_afs_rotate(op, afs_rotate_trace_aborted, abort_code);
		op->cumul_error.responded = true;
		switch (abort_code) {
		case VNOVOL:
			/* This fileserver doesn't know about the volume.
			 * - May indicate that the VL is wrong - retry once and compare
			 *   the results.
			 * - May indicate that the fileserver couldn't attach to the vol.
			 * - The volume might have been temporarily removed so that it can
			 *   be replaced by a volume restore.  "vos" might have ended one
			 *   transaction and has yet to create the next.
			 * - The volume might not be blessed or might not be in-service
			 *   (administrative action).
			 */
			if (op->flags & AFS_OPERATION_VNOVOL) {
				afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
				goto next_server;
			}

			write_lock(&op->volume->servers_lock);
			op->server_list->vnovol_mask |= 1 << op->server_index;
			write_unlock(&op->volume->servers_lock);

			set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags);
			error = afs_check_volume_status(op->volume, op);
			if (error < 0) {
				afs_op_set_error(op, error);
				goto failed;
			}

			if (test_bit(AFS_VOLUME_DELETED, &op->volume->flags)) {
				afs_op_set_error(op, -ENOMEDIUM);
				goto failed;
			}

			/* If the server list didn't change, then assume that
			 * it's the fileserver having trouble.
			 */
			if (rcu_access_pointer(op->volume->servers) == op->server_list) {
				afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
				goto next_server;
			}

			/* Try again */
			op->flags |= AFS_OPERATION_VNOVOL;
			_leave(" = t [vnovol]");
			return true;

		case VVOLEXISTS:
		case VONLINE:
			/* These should not be returned from the fileserver. */
			pr_warn("Fileserver returned unexpected abort %d\n",
				abort_code);
			afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
			goto next_server;

		case VNOSERVICE:
			/* Prior to AFS 3.2 VNOSERVICE was returned from the fileserver
			 * if the volume was neither in-service nor administratively
			 * blessed.  All usage was replaced by VNOVOL because AFS 3.1 and
			 * earlier cache managers did not handle VNOSERVICE and assumed
			 * it was the client OSes errno 105.
			 *
			 * Starting with OpenAFS 1.4.8 VNOSERVICE was repurposed as the
			 * fileserver idle dead time error which was sent in place of
			 * RX_CALL_TIMEOUT (-3).  The error was intended to be sent if the
			 * fileserver took too long to send a reply to the client.
			 * RX_CALL_TIMEOUT would have caused the cache manager to mark the
			 * server down whereas VNOSERVICE since AFS 3.2 would cause cache
			 * manager to temporarily (up to 15 minutes) mark the volume
			 * instance as unusable.
			 *
			 * The idle dead logic resulted in cache inconsistency since a
			 * state changing call that the cache manager assumed was dead
			 * could still be processed to completion by the fileserver.  This
			 * logic was removed in OpenAFS 1.8.0 and VNOSERVICE is no longer
			 * returned.  However, many 1.4.8 through 1.6.24 fileservers are
			 * still in existence.
			 *
			 * AuriStorFS fileservers have never returned VNOSERVICE.
			 *
			 * VNOSERVICE should be treated as an alias for RX_CALL_TIMEOUT.
			 */
		case RX_CALL_TIMEOUT:
			afs_op_accumulate_error(op, -ETIMEDOUT, abort_code);
			goto next_server;

		case VSALVAGING: /* This error should not be leaked to cache managers
				  * but is from OpenAFS demand attach fileservers.
				  * It should be treated as an alias for VOFFLINE.
				  */
		case VSALVAGE: /* VSALVAGE should be treated as a synonym of VOFFLINE */
		case VOFFLINE:
			/* The volume is in use by the volserver or another volume utility
			 * for an operation that might alter the contents.  The volume is
			 * expected to come back but it might take a long time (could be
			 * days).
			 */
			if (!test_and_set_bit(AFS_VOLUME_OFFLINE, &op->volume->flags)) {
				afs_busy(op->volume, abort_code);
				clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
			}
			if (op->flags & AFS_OPERATION_NO_VSLEEP) {
				afs_op_set_error(op, -EADV);
				goto failed;
			}
			goto busy;

		case VRESTARTING: /* The fileserver is either shutting down or starting up. */
		case VBUSY:
			/* The volume is in use by the volserver or another volume
			 * utility for an operation that is not expected to alter the
			 * contents of the volume.  VBUSY does not need to be returned
			 * for a ROVOL or BACKVOL bound to an ITBusy volserver
			 * transaction.  The fileserver is permitted to continue serving
			 * content from ROVOLs and BACKVOLs during an ITBusy transaction
			 * because the content will not change.  However, many fileserver
			 * releases do return VBUSY for ROVOL and BACKVOL instances under
			 * many circumstances.
			 *
			 * Retry after going round all the servers unless we have a file
			 * lock we need to maintain.
			 */
			if (op->flags & AFS_OPERATION_NO_VSLEEP) {
				afs_op_set_error(op, -EBUSY);
				goto failed;
			}
			if (!test_and_set_bit(AFS_VOLUME_BUSY, &op->volume->flags)) {
				afs_busy(op->volume, abort_code);
				clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
			}
		busy:
			if (op->flags & AFS_OPERATION_CUR_ONLY) {
				if (!afs_sleep_and_retry(op))
					goto failed;

				/* Retry with same server & address */
				_leave(" = t [vbusy]");
				return true;
			}

			op->flags |= AFS_OPERATION_VBUSY;
			goto next_server;

		case VMOVED:
			/* The volume migrated to another server.  We consider
			 * consider all locks and callbacks broken and request
			 * an update from the VLDB.
			 *
			 * We also limit the number of VMOVED hops we will
			 * honour, just in case someone sets up a loop.
			 */
			if (op->flags & AFS_OPERATION_VMOVED) {
				afs_op_set_error(op, -EREMOTEIO);
				goto failed;
			}
			op->flags |= AFS_OPERATION_VMOVED;

			set_bit(AFS_VOLUME_WAIT, &op->volume->flags);
			set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags);
			error = afs_check_volume_status(op->volume, op);
			if (error < 0) {
				afs_op_set_error(op, error);
				goto failed;
			}

			/* If the server list didn't change, then the VLDB is
			 * out of sync with the fileservers.  This is hopefully
			 * a temporary condition, however, so we don't want to
			 * permanently block access to the file.
			 *
			 * TODO: Try other fileservers if we can.
			 *
			 * TODO: Retry a few times with sleeps.
			 */
			if (rcu_access_pointer(op->volume->servers) == op->server_list) {
				afs_op_accumulate_error(op, -ENOMEDIUM, abort_code);
				goto failed;
			}

			goto restart_from_beginning;

		case UAEIO:
		case VIO:
			afs_op_accumulate_error(op, -EREMOTEIO, abort_code);
			if (op->volume->type != AFSVL_RWVOL)
				goto next_server;
			goto failed;

		case VDISKFULL:
		case UAENOSPC:
			/* The partition is full.  Only applies to RWVOLs.
			 * Translate locally and return ENOSPC.
			 * No replicas to failover to.
			 */
			afs_op_set_error(op, -ENOSPC);
			goto failed_but_online;

		case VOVERQUOTA:
		case UAEDQUOT:
			/* Volume is full.  Only applies to RWVOLs.
			 * Translate locally and return EDQUOT.
			 * No replicas to failover to.
			 */
			afs_op_set_error(op, -EDQUOT);
			goto failed_but_online;

		default:
			afs_op_accumulate_error(op, error, abort_code);
		failed_but_online:
			clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
			clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
			goto failed;
		}

	case -ETIMEDOUT:
	case -ETIME:
		if (afs_op_error(op) != -EDESTADDRREQ)
			goto iterate_address;
		fallthrough;
	case -ERFKILL:
	case -EADDRNOTAVAIL:
	case -ENETUNREACH:
	case -EHOSTUNREACH:
	case -EHOSTDOWN:
	case -ECONNREFUSED:
		_debug("no conn");
		afs_op_accumulate_error(op, error, 0);
		goto iterate_address;

	case -ENETRESET:
		pr_warn("kAFS: Peer reset %s (op=%x)\n",
			op->type ? op->type->name : "???", op->debug_id);
		fallthrough;
	case -ECONNRESET:
		_debug("call reset");
		afs_op_set_error(op, error);
		goto failed;
	}

restart_from_beginning:
	trace_afs_rotate(op, afs_rotate_trace_restart, 0);
	_debug("restart");
	op->estate = NULL;
	op->server = NULL;
	afs_clear_server_states(op);
	op->server_states = NULL;
	afs_put_serverlist(op->net, op->server_list);
	op->server_list = NULL;
start:
	_debug("start");
	ASSERTCMP(op->estate, ==, NULL);
	/* See if we need to do an update of the volume record.  Note that the
	 * volume may have moved or even have been deleted.
	 */
	error = afs_check_volume_status(op->volume, op);
	trace_afs_rotate(op, afs_rotate_trace_check_vol_status, error);
	if (error < 0) {
		afs_op_set_error(op, error);
		goto failed;
	}

	if (!afs_start_fs_iteration(op, vnode))
		goto failed;

	_debug("__ VOL %llx __", op->volume->vid);

pick_server:
	_debug("pick [%lx]", op->untried_servers);
	ASSERTCMP(op->estate, ==, NULL);

	error = afs_wait_for_fs_probes(op, op->server_states,
				       !(op->flags & AFS_OPERATION_UNINTR));
	switch (error) {
	case 0: /* No untried responsive servers and no outstanding probes */
		trace_afs_rotate(op, afs_rotate_trace_probe_none, 0);
		goto no_more_servers;
	case 1: /* Got a response */
		trace_afs_rotate(op, afs_rotate_trace_probe_response, 0);
		break;
	case 2: /* Probe data superseded */
		trace_afs_rotate(op, afs_rotate_trace_probe_superseded, 0);
		goto restart_from_beginning;
	default:
		trace_afs_rotate(op, afs_rotate_trace_probe_error, error);
		afs_op_set_error(op, error);
		goto failed;
	}

	/* Pick the untried server with the highest priority untried endpoint.
	 * If we have outstanding callbacks, we stick with the server we're
	 * already using if we can.
	 */
	if (op->server) {
		_debug("server %u", op->server_index);
		if (test_bit(op->server_index, &op->untried_servers))
			goto selected_server;
		op->server = NULL;
		_debug("no server");
	}

	rcu_read_lock();
	op->server_index = -1;
	best_prio = -1;
	for (i = 0; i < op->server_list->nr_servers; i++) {
		struct afs_endpoint_state *es;
		struct afs_server_entry *se = &op->server_list->servers[i];
		struct afs_addr_list *sal;
		struct afs_server *s = se->server;

		if (!test_bit(i, &op->untried_servers) ||
		    test_bit(AFS_SE_EXCLUDED, &se->flags) ||
		    !test_bit(AFS_SERVER_FL_RESPONDING, &s->flags))
			continue;
		es = op->server_states->endpoint_state;
		sal = es->addresses;

		afs_get_address_preferences_rcu(op->net, sal);
		for (j = 0; j < sal->nr_addrs; j++) {
			if (!sal->addrs[j].peer)
				continue;
			if (sal->addrs[j].prio > best_prio) {
				op->server_index = i;
				best_prio = sal->addrs[j].prio;
			}
		}
	}
	rcu_read_unlock();

	if (op->server_index == -1)
		goto no_more_servers;

selected_server:
	trace_afs_rotate(op, afs_rotate_trace_selected_server, best_prio);
	_debug("use %d prio %u", op->server_index, best_prio);
	__clear_bit(op->server_index, &op->untried_servers);

	/* We're starting on a different fileserver from the list.  We need to
	 * check it, create a callback intercept, find its address list and
	 * probe its capabilities before we use it.
	 */
	ASSERTCMP(op->estate, ==, NULL);
	server = op->server_list->servers[op->server_index].server;

	if (!afs_check_server_record(op, server, op->key))
		goto failed;

	_debug("USING SERVER: %pU", &server->uuid);

	op->flags |= AFS_OPERATION_RETRY_SERVER;
	op->server = server;
	if (vnode->cb_server != server) {
		vnode->cb_server = server;
		vnode->cb_v_check = atomic_read(&vnode->volume->cb_v_break);
		atomic64_set(&vnode->cb_expires_at, AFS_NO_CB_PROMISE);
	}

retry_server:
	op->addr_tried = 0;
	op->addr_index = -1;

iterate_address:
	/* Iterate over the current server's address list to try and find an
	 * address on which it will respond to us.
	 */
	op->estate = op->server_states[op->server_index].endpoint_state;
	set = READ_ONCE(op->estate->responsive_set);
	failed = READ_ONCE(op->estate->failed_set);
	_debug("iterate ES=%x rs=%lx fs=%lx", op->estate->probe_seq, set, failed);
	set &= ~(failed | op->addr_tried);
	trace_afs_rotate(op, afs_rotate_trace_iterate_addr, set);
	if (!set)
		goto wait_for_more_probe_results;

	alist = op->estate->addresses;
	for (i = 0; i < alist->nr_addrs; i++) {
		if (alist->addrs[i].prio > best_prio) {
			addr_index = i;
			best_prio = alist->addrs[i].prio;
		}
	}

	addr_index = READ_ONCE(alist->preferred);
	if (!test_bit(addr_index, &set))
		addr_index = __ffs(set);

	op->addr_index = addr_index;
	set_bit(addr_index, &op->addr_tried);

	op->volsync.creation = TIME64_MIN;
	op->volsync.update = TIME64_MIN;
	op->call_responded = false;
	_debug("address [%u] %u/%u %pISp",
	       op->server_index, addr_index, alist->nr_addrs,
	       rxrpc_kernel_remote_addr(alist->addrs[op->addr_index].peer));
	_leave(" = t");
	return true;

wait_for_more_probe_results:
	error = afs_wait_for_one_fs_probe(op->server, op->estate, op->addr_tried,
					  !(op->flags & AFS_OPERATION_UNINTR));
	if (!error)
		goto iterate_address;

	/* We've now had a failure to respond on all of a server's addresses -
	 * immediately probe them again and consider retrying the server.
	 */
	trace_afs_rotate(op, afs_rotate_trace_probe_fileserver, 0);
	afs_probe_fileserver(op->net, op->server);
	if (op->flags & AFS_OPERATION_RETRY_SERVER) {
		error = afs_wait_for_one_fs_probe(op->server, op->estate, op->addr_tried,
						  !(op->flags & AFS_OPERATION_UNINTR));
		switch (error) {
		case 0:
			op->flags &= ~AFS_OPERATION_RETRY_SERVER;
			trace_afs_rotate(op, afs_rotate_trace_retry_server, 0);
			goto retry_server;
		case -ERESTARTSYS:
			afs_op_set_error(op, error);
			goto failed;
		case -ETIME:
		case -EDESTADDRREQ:
			goto next_server;
		}
	}

next_server:
	trace_afs_rotate(op, afs_rotate_trace_next_server, 0);
	_debug("next");
	ASSERT(op->estate);
	alist = op->estate->addresses;
	if (op->call_responded &&
	    op->addr_index != READ_ONCE(alist->preferred) &&
	    test_bit(alist->preferred, &op->addr_tried))
		WRITE_ONCE(alist->preferred, op->addr_index);
	op->estate = NULL;
	goto pick_server;

no_more_servers:
	/* That's all the servers poked to no good effect.  Try again if some
	 * of them were busy.
	 */
	trace_afs_rotate(op, afs_rotate_trace_no_more_servers, 0);
	if (op->flags & AFS_OPERATION_VBUSY) {
		afs_sleep_and_retry(op);
		op->flags &= ~AFS_OPERATION_VBUSY;
		goto restart_from_beginning;
	}

	rcu_read_lock();
	for (i = 0; i < op->server_list->nr_servers; i++) {
		struct afs_endpoint_state *estate;

		estate = op->server_states->endpoint_state;
		error = READ_ONCE(estate->error);
		if (error < 0)
			afs_op_accumulate_error(op, error, estate->abort_code);
	}
	rcu_read_unlock();

failed:
	trace_afs_rotate(op, afs_rotate_trace_failed, 0);
	op->flags |= AFS_OPERATION_STOP;
	if (op->estate) {
		alist = op->estate->addresses;
		if (op->call_responded &&
		    op->addr_index != READ_ONCE(alist->preferred) &&
		    test_bit(alist->preferred, &op->addr_tried))
			WRITE_ONCE(alist->preferred, op->addr_index);
		op->estate = NULL;
	}
	_leave(" = f [failed %d]", afs_op_error(op));
	return false;
}

/*
 * Dump cursor state in the case of the error being EDESTADDRREQ.
 */
void afs_dump_edestaddrreq(const struct afs_operation *op)
{
	static int count;
	int i;

	if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3)
		return;
	count++;

	rcu_read_lock();

	pr_notice("EDESTADDR occurred\n");
	pr_notice("OP: cbb=%x cbb2=%x fl=%x err=%hd\n",
		  op->file[0].cb_break_before,
		  op->file[1].cb_break_before, op->flags, op->cumul_error.error);
	pr_notice("OP: ut=%lx ix=%d ni=%u\n",
		  op->untried_servers, op->server_index, op->nr_iterations);
	pr_notice("OP: call  er=%d ac=%d r=%u\n",
		  op->call_error, op->call_abort_code, op->call_responded);

	if (op->server_list) {
		const struct afs_server_list *sl = op->server_list;

		pr_notice("FC: SL nr=%u vnov=%hx\n",
			  sl->nr_servers, sl->vnovol_mask);
		for (i = 0; i < sl->nr_servers; i++) {
			const struct afs_server *s = sl->servers[i].server;
			const struct afs_endpoint_state *e =
				rcu_dereference(s->endpoint_state);
			const struct afs_addr_list *a = e->addresses;

			pr_notice("FC: server fl=%lx av=%u %pU\n",
				  s->flags, s->addr_version, &s->uuid);
			pr_notice("FC:  - pq=%x R=%lx F=%lx\n",
				  e->probe_seq, e->responsive_set, e->failed_set);
			if (a) {
				pr_notice("FC:  - av=%u nr=%u/%u/%u pr=%u\n",
					  a->version,
					  a->nr_ipv4, a->nr_addrs, a->max_addrs,
					  a->preferred);
				if (a == e->addresses)
					pr_notice("FC:  - current\n");
			}
		}
	}

	pr_notice("AC: t=%lx ax=%d\n", op->addr_tried, op->addr_index);
	rcu_read_unlock();
}