aboutsummaryrefslogblamecommitdiffstats
path: root/fs/afs/vlocation.c
blob: eced20618eccf2bfc23a1bc7d9b3abefc2ded9a1 (plain) (tree)
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
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
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
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                        
/* vlocation.c: volume location management
 *
 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include "volume.h"
#include "cell.h"
#include "cmservice.h"
#include "fsclient.h"
#include "vlclient.h"
#include "kafstimod.h"
#include <rxrpc/connection.h>
#include "internal.h"

#define AFS_VLDB_TIMEOUT HZ*1000

static void afs_vlocation_update_timer(struct afs_timer *timer);
static void afs_vlocation_update_attend(struct afs_async_op *op);
static void afs_vlocation_update_discard(struct afs_async_op *op);
static void __afs_put_vlocation(struct afs_vlocation *vlocation);

static void __afs_vlocation_timeout(struct afs_timer *timer)
{
	struct afs_vlocation *vlocation =
		list_entry(timer, struct afs_vlocation, timeout);

	_debug("VL TIMEOUT [%s{u=%d}]",
	       vlocation->vldb.name, atomic_read(&vlocation->usage));

	afs_vlocation_do_timeout(vlocation);
}

static const struct afs_timer_ops afs_vlocation_timer_ops = {
	.timed_out	= __afs_vlocation_timeout,
};

static const struct afs_timer_ops afs_vlocation_update_timer_ops = {
	.timed_out	= afs_vlocation_update_timer,
};

static const struct afs_async_op_ops afs_vlocation_update_op_ops = {
	.attend		= afs_vlocation_update_attend,
	.discard	= afs_vlocation_update_discard,
};

static LIST_HEAD(afs_vlocation_update_pendq);	/* queue of VLs awaiting update */
static struct afs_vlocation *afs_vlocation_update;	/* VL currently being updated */
static DEFINE_SPINLOCK(afs_vlocation_update_lock); /* lock guarding update queue */

#ifdef AFS_CACHING_SUPPORT
static cachefs_match_val_t afs_vlocation_cache_match(void *target,
						     const void *entry);
static void afs_vlocation_cache_update(void *source, void *entry);

struct cachefs_index_def afs_vlocation_cache_index_def = {
	.name		= "vldb",
	.data_size	= sizeof(struct afs_cache_vlocation),
	.keys[0]	= { CACHEFS_INDEX_KEYS_ASCIIZ, 64 },
	.match		= afs_vlocation_cache_match,
	.update		= afs_vlocation_cache_update,
};
#endif

/*****************************************************************************/
/*
 * iterate through the VL servers in a cell until one of them admits knowing
 * about the volume in question
 * - caller must have cell->vl_sem write-locked
 */
static int afs_vlocation_access_vl_by_name(struct afs_vlocation *vlocation,
					   const char *name,
					   unsigned namesz,
					   struct afs_cache_vlocation *vldb)
{
	struct afs_server *server = NULL;
	struct afs_cell *cell = vlocation->cell;
	int count, ret;

	_enter("%s,%*.*s,%u", cell->name, namesz, namesz, name, namesz);

	ret = -ENOMEDIUM;
	for (count = cell->vl_naddrs; count > 0; count--) {
		_debug("CellServ[%hu]: %08x",
		       cell->vl_curr_svix,
		       cell->vl_addrs[cell->vl_curr_svix].s_addr);

		/* try and create a server */
		ret = afs_server_lookup(cell,
					&cell->vl_addrs[cell->vl_curr_svix],
					&server);
		switch (ret) {
		case 0:
			break;
		case -ENOMEM:
		case -ENONET:
			goto out;
		default:
			goto rotate;
		}

		/* attempt to access the VL server */
		ret = afs_rxvl_get_entry_by_name(server, name, namesz, vldb);
		switch (ret) {
		case 0:
			afs_put_server(server);
			goto out;
		case -ENOMEM:
		case -ENONET:
		case -ENETUNREACH:
		case -EHOSTUNREACH:
		case -ECONNREFUSED:
			down_write(&server->sem);
			if (server->vlserver) {
				rxrpc_put_connection(server->vlserver);
				server->vlserver = NULL;
			}
			up_write(&server->sem);
			afs_put_server(server);
			if (ret == -ENOMEM || ret == -ENONET)
				goto out;
			goto rotate;
		case -ENOMEDIUM:
			afs_put_server(server);
			goto out;
		default:
			afs_put_server(server);
			ret = -ENOMEDIUM;
			goto rotate;
		}

		/* rotate the server records upon lookup failure */
	rotate:
		cell->vl_curr_svix++;
		cell->vl_curr_svix %= cell->vl_naddrs;
	}

 out:
	_leave(" = %d", ret);
	return ret;

} /* end afs_vlocation_access_vl_by_name() */

/*****************************************************************************/
/*
 * iterate through the VL servers in a cell until one of them admits knowing
 * about the volume in question
 * - caller must have cell->vl_sem write-locked
 */
static int afs_vlocation_access_vl_by_id(struct afs_vlocation *vlocation,
					 afs_volid_t volid,
					 afs_voltype_t voltype,
					 struct afs_cache_vlocation *vldb)
{
	struct afs_server *server = NULL;
	struct afs_cell *cell = vlocation->cell;
	int count, ret;

	_enter("%s,%x,%d,", cell->name, volid, voltype);

	ret = -ENOMEDIUM;
	for (count = cell->vl_naddrs; count > 0; count--) {
		_debug("CellServ[%hu]: %08x",
		       cell->vl_curr_svix,
		       cell->vl_addrs[cell->vl_curr_svix].s_addr);

		/* try and create a server */
		ret = afs_server_lookup(cell,
					&cell->vl_addrs[cell->vl_curr_svix],
					&server);
		switch (ret) {
		case 0:
			break;
		case -ENOMEM:
		case -ENONET:
			goto out;
		default:
			goto rotate;
		}

		/* attempt to access the VL server */
		ret = afs_rxvl_get_entry_by_id(server, volid, voltype, vldb);
		switch (ret) {
		case 0:
			afs_put_server(server);
			goto out;
		case -ENOMEM:
		case -ENONET:
		case -ENETUNREACH:
		case -EHOSTUNREACH:
		case -ECONNREFUSED:
			down_write(&server->sem);
			if (server->vlserver) {
				rxrpc_put_connection(server->vlserver);
				server->vlserver = NULL;
			}
			up_write(&server->sem);
			afs_put_server(server);
			if (ret == -ENOMEM || ret == -ENONET)
				goto out;
			goto rotate;
		case -ENOMEDIUM:
			afs_put_server(server);
			goto out;
		default:
			afs_put_server(server);
			ret = -ENOMEDIUM;
			goto rotate;
		}

		/* rotate the server records upon lookup failure */
	rotate:
		cell->vl_curr_svix++;
		cell->vl_curr_svix %= cell->vl_naddrs;
	}

 out:
	_leave(" = %d", ret);
	return ret;

} /* end afs_vlocation_access_vl_by_id() */

/*****************************************************************************/
/*
 * lookup volume location
 * - caller must have cell->vol_sem write-locked
 * - iterate through the VL servers in a cell until one of them admits knowing
 *   about the volume in question
 * - lookup in the local cache if not able to find on the VL server
 * - insert/update in the local cache if did get a VL response
 */
int afs_vlocation_lookup(struct afs_cell *cell,
			 const char *name,
			 unsigned namesz,
			 struct afs_vlocation **_vlocation)
{
	struct afs_cache_vlocation vldb;
	struct afs_vlocation *vlocation;
	afs_voltype_t voltype;
	afs_volid_t vid;
	int active = 0, ret;

	_enter("{%s},%*.*s,%u,", cell->name, namesz, namesz, name, namesz);

	if (namesz > sizeof(vlocation->vldb.name)) {
		_leave(" = -ENAMETOOLONG");
		return -ENAMETOOLONG;
	}

	/* search the cell's active list first */
	list_for_each_entry(vlocation, &cell->vl_list, link) {
		if (namesz < sizeof(vlocation->vldb.name) &&
		    vlocation->vldb.name[namesz] != '\0')
			continue;

		if (memcmp(vlocation->vldb.name, name, namesz) == 0)
			goto found_in_memory;
	}

	/* search the cell's graveyard list second */
	spin_lock(&cell->vl_gylock);
	list_for_each_entry(vlocation, &cell->vl_graveyard, link) {
		if (namesz < sizeof(vlocation->vldb.name) &&
		    vlocation->vldb.name[namesz] != '\0')
			continue;

		if (memcmp(vlocation->vldb.name, name, namesz) == 0)
			goto found_in_graveyard;
	}
	spin_unlock(&cell->vl_gylock);

	/* not in the cell's in-memory lists - create a new record */
	vlocation = kmalloc(sizeof(struct afs_vlocation), GFP_KERNEL);
	if (!vlocation)
		return -ENOMEM;

	memset(vlocation, 0, sizeof(struct afs_vlocation));
	atomic_set(&vlocation->usage, 1);
	INIT_LIST_HEAD(&vlocation->link);
	rwlock_init(&vlocation->lock);
	memcpy(vlocation->vldb.name, name, namesz);

	afs_timer_init(&vlocation->timeout, &afs_vlocation_timer_ops);
	afs_timer_init(&vlocation->upd_timer, &afs_vlocation_update_timer_ops);
	afs_async_op_init(&vlocation->upd_op, &afs_vlocation_update_op_ops);

	afs_get_cell(cell);
	vlocation->cell = cell;

	list_add_tail(&vlocation->link, &cell->vl_list);

#ifdef AFS_CACHING_SUPPORT
	/* we want to store it in the cache, plus it might already be
	 * encached */
	cachefs_acquire_cookie(cell->cache,
			       &afs_volume_cache_index_def,
			       vlocation,
			       &vlocation->cache);

	if (vlocation->valid)
		goto found_in_cache;
#endif

	/* try to look up an unknown volume in the cell VL databases by name */
	ret = afs_vlocation_access_vl_by_name(vlocation, name, namesz, &vldb);
	if (ret < 0) {
		printk("kAFS: failed to locate '%*.*s' in cell '%s'\n",
		       namesz, namesz, name, cell->name);
		goto error;
	}

	goto found_on_vlserver;

 found_in_graveyard:
	/* found in the graveyard - resurrect */
	_debug("found in graveyard");
	atomic_inc(&vlocation->usage);
	list_del(&vlocation->link);
	list_add_tail(&vlocation->link, &cell->vl_list);
	spin_unlock(&cell->vl_gylock);

	afs_kafstimod_del_timer(&vlocation->timeout);
	goto active;

 found_in_memory:
	/* found in memory - check to see if it's active */
	_debug("found in memory");
	atomic_inc(&vlocation->usage);

 active:
	active = 1;

#ifdef AFS_CACHING_SUPPORT
 found_in_cache:
#endif
	/* try to look up a cached volume in the cell VL databases by ID */
	_debug("found in cache");

	_debug("Locally Cached: %s %02x { %08x(%x) %08x(%x) %08x(%x) }",
	       vlocation->vldb.name,
	       vlocation->vldb.vidmask,
	       ntohl(vlocation->vldb.servers[0].s_addr),
	       vlocation->vldb.srvtmask[0],
	       ntohl(vlocation->vldb.servers[1].s_addr),
	       vlocation->vldb.srvtmask[1],
	       ntohl(vlocation->vldb.servers[2].s_addr),
	       vlocation->vldb.srvtmask[2]
	       );

	_debug("Vids: %08x %08x %08x",
	       vlocation->vldb.vid[0],
	       vlocation->vldb.vid[1],
	       vlocation->vldb.vid[2]);

	if (vlocation->vldb.vidmask & AFS_VOL_VTM_RW) {
		vid = vlocation->vldb.vid[0];
		voltype = AFSVL_RWVOL;
	}
	else if (vlocation->vldb.vidmask & AFS_VOL_VTM_RO) {
		vid = vlocation->vldb.vid[1];
		voltype = AFSVL_ROVOL;
	}
	else if (vlocation->vldb.vidmask & AFS_VOL_VTM_BAK) {
		vid = vlocation->vldb.vid[2];
		voltype = AFSVL_BACKVOL;
	}
	else {
		BUG();
		vid = 0;
		voltype = 0;
	}

	ret = afs_vlocation_access_vl_by_id(vlocation, vid, voltype, &vldb);
	switch (ret) {
		/* net error */
	default:
		printk("kAFS: failed to volume '%*.*s' (%x) up in '%s': %d\n",
		       namesz, namesz, name, vid, cell->name, ret);
		goto error;

		/* pulled from local cache into memory */
	case 0:
		goto found_on_vlserver;

		/* uh oh... looks like the volume got deleted */
	case -ENOMEDIUM:
		printk("kAFS: volume '%*.*s' (%x) does not exist '%s'\n",
		       namesz, namesz, name, vid, cell->name);

		/* TODO: make existing record unavailable */
		goto error;
	}

 found_on_vlserver:
	_debug("Done VL Lookup: %*.*s %02x { %08x(%x) %08x(%x) %08x(%x) }",
	       namesz, namesz, name,
	       vldb.vidmask,
	       ntohl(vldb.servers[0].s_addr), vldb.srvtmask[0],
	       ntohl(vldb.servers[1].s_addr), vldb.srvtmask[1],
	       ntohl(vldb.servers[2].s_addr), vldb.srvtmask[2]
	       );

	_debug("Vids: %08x %08x %08x", vldb.vid[0], vldb.vid[1], vldb.vid[2]);

	if ((namesz < sizeof(vlocation->vldb.name) &&
	     vlocation->vldb.name[namesz] != '\0') ||
	    memcmp(vldb.name, name, namesz) != 0)
		printk("kAFS: name of volume '%*.*s' changed to '%s' on server\n",
		       namesz, namesz, name, vldb.name);

	memcpy(&vlocation->vldb, &vldb, sizeof(vlocation->vldb));

	afs_kafstimod_add_timer(&vlocation->upd_timer, 10 * HZ);

#ifdef AFS_CACHING_SUPPORT
	/* update volume entry in local cache */
	cachefs_update_cookie(vlocation->cache);
#endif

	*_vlocation = vlocation;
	_leave(" = 0 (%p)",vlocation);
	return 0;

 error:
	if (vlocation) {
		if (active) {
			__afs_put_vlocation(vlocation);
		}
		else {
			list_del(&vlocation->link);
#ifdef AFS_CACHING_SUPPORT
			cachefs_relinquish_cookie(vlocation->cache, 0);
#endif
			afs_put_cell(vlocation->cell);
			kfree(vlocation);
		}
	}

	_leave(" = %d", ret);
	return ret;
} /* end afs_vlocation_lookup() */

/*****************************************************************************/
/*
 * finish using a volume location record
 * - caller must have cell->vol_sem write-locked
 */
static void __afs_put_vlocation(struct afs_vlocation *vlocation)
{
	struct afs_cell *cell;

	if (!vlocation)
		return;

	_enter("%s", vlocation->vldb.name);

	cell = vlocation->cell;

	/* sanity check */
	BUG_ON(atomic_read(&vlocation->usage) <= 0);

	spin_lock(&cell->vl_gylock);
	if (likely(!atomic_dec_and_test(&vlocation->usage))) {
		spin_unlock(&cell->vl_gylock);
		_leave("");
		return;
	}

	/* move to graveyard queue */
	list_del(&vlocation->link);
	list_add_tail(&vlocation->link,&cell->vl_graveyard);

	/* remove from pending timeout queue (refcounted if actually being
	 * updated) */
	list_del_init(&vlocation->upd_op.link);

	/* time out in 10 secs */
	afs_kafstimod_del_timer(&vlocation->upd_timer);
	afs_kafstimod_add_timer(&vlocation->timeout, 10 * HZ);

	spin_unlock(&cell->vl_gylock);

	_leave(" [killed]");
} /* end __afs_put_vlocation() */

/*****************************************************************************/
/*
 * finish using a volume location record
 */
void afs_put_vlocation(struct afs_vlocation *vlocation)
{
	if (vlocation) {
		struct afs_cell *cell = vlocation->cell;

		down_write(&cell->vl_sem);
		__afs_put_vlocation(vlocation);
		up_write(&cell->vl_sem);
	}
} /* end afs_put_vlocation() */

/*****************************************************************************/
/*
 * timeout vlocation record
 * - removes from the cell's graveyard if the usage count is zero
 */
void afs_vlocation_do_timeout(struct afs_vlocation *vlocation)
{
	struct afs_cell *cell;

	_enter("%s", vlocation->vldb.name);

	cell = vlocation->cell;

	BUG_ON(atomic_read(&vlocation->usage) < 0);

	/* remove from graveyard if still dead */
	spin_lock(&cell->vl_gylock);
	if (atomic_read(&vlocation->usage) == 0)
		list_del_init(&vlocation->link);
	else
		vlocation = NULL;
	spin_unlock(&cell->vl_gylock);

	if (!vlocation) {
		_leave("");
		return; /* resurrected */
	}

	/* we can now destroy it properly */
#ifdef AFS_CACHING_SUPPORT
	cachefs_relinquish_cookie(vlocation->cache, 0);
#endif
	afs_put_cell(cell);

	kfree(vlocation);

	_leave(" [destroyed]");
} /* end afs_vlocation_do_timeout() */

/*****************************************************************************/
/*
 * send an update operation to the currently selected server
 */
static int afs_vlocation_update_begin(struct afs_vlocation *vlocation)
{
	afs_voltype_t voltype;
	afs_volid_t vid;
	int ret;

	_enter("%s{ufs=%u ucs=%u}",
	       vlocation->vldb.name,
	       vlocation->upd_first_svix,
	       vlocation->upd_curr_svix);

	/* try to look up a cached volume in the cell VL databases by ID */
	if (vlocation->vldb.vidmask & AFS_VOL_VTM_RW) {
		vid = vlocation->vldb.vid[0];
		voltype = AFSVL_RWVOL;
	}
	else if (vlocation->vldb.vidmask & AFS_VOL_VTM_RO) {
		vid = vlocation->vldb.vid[1];
		voltype = AFSVL_ROVOL;
	}
	else if (vlocation->vldb.vidmask & AFS_VOL_VTM_BAK) {
		vid = vlocation->vldb.vid[2];
		voltype = AFSVL_BACKVOL;
	}
	else {
		BUG();
		vid = 0;
		voltype = 0;
	}

	/* contact the chosen server */
	ret = afs_server_lookup(
		vlocation->cell,
		&vlocation->cell->vl_addrs[vlocation->upd_curr_svix],
		&vlocation->upd_op.server);

	switch (ret) {
	case 0:
		break;
	case -ENOMEM:
	case -ENONET:
	default:
		_leave(" = %d", ret);
		return ret;
	}

	/* initiate the update operation */
	ret = afs_rxvl_get_entry_by_id_async(&vlocation->upd_op, vid, voltype);
	if (ret < 0) {
		_leave(" = %d", ret);
		return ret;
	}

	_leave(" = %d", ret);
	return ret;
} /* end afs_vlocation_update_begin() */

/*****************************************************************************/
/*
 * abandon updating a VL record
 * - does not restart the update timer
 */
static void afs_vlocation_update_abandon(struct afs_vlocation *vlocation,
					 afs_vlocation_upd_t state,
					 int ret)
{
	_enter("%s,%u", vlocation->vldb.name, state);

	if (ret < 0)
		printk("kAFS: Abandoning VL update '%s': %d\n",
		       vlocation->vldb.name, ret);

	/* discard the server record */
	afs_put_server(vlocation->upd_op.server);
	vlocation->upd_op.server = NULL;

	spin_lock(&afs_vlocation_update_lock);
	afs_vlocation_update = NULL;
	vlocation->upd_state = state;

	/* TODO: start updating next VL record on pending list */

	spin_unlock(&afs_vlocation_update_lock);

	_leave("");
} /* end afs_vlocation_update_abandon() */

/*****************************************************************************/
/*
 * handle periodic update timeouts and busy retry timeouts
 * - called from kafstimod
 */
static void afs_vlocation_update_timer(struct afs_timer *timer)
{
	struct afs_vlocation *vlocation =
		list_entry(timer, struct afs_vlocation, upd_timer);
	int ret;

	_enter("%s", vlocation->vldb.name);

	/* only update if not in the graveyard (defend against putting too) */
	spin_lock(&vlocation->cell->vl_gylock);

	if (!atomic_read(&vlocation->usage))
		goto out_unlock1;

	spin_lock(&afs_vlocation_update_lock);

	/* if we were woken up due to EBUSY sleep then restart immediately if
	 * possible or else jump to front of pending queue */
	if (vlocation->upd_state == AFS_VLUPD_BUSYSLEEP) {
		if (afs_vlocation_update) {
			list_add(&vlocation->upd_op.link,
				 &afs_vlocation_update_pendq);
		}
		else {
			afs_get_vlocation(vlocation);
			afs_vlocation_update = vlocation;
			vlocation->upd_state = AFS_VLUPD_INPROGRESS;
		}
		goto out_unlock2;
	}

	/* put on pending queue if there's already another update in progress */
	if (afs_vlocation_update) {
		vlocation->upd_state = AFS_VLUPD_PENDING;
		list_add_tail(&vlocation->upd_op.link,
			      &afs_vlocation_update_pendq);
		goto out_unlock2;
	}

	/* hold a ref on it while actually updating */
	afs_get_vlocation(vlocation);
	afs_vlocation_update = vlocation;
	vlocation->upd_state = AFS_VLUPD_INPROGRESS;

	spin_unlock(&afs_vlocation_update_lock);
	spin_unlock(&vlocation->cell->vl_gylock);

	/* okay... we can start the update */
	_debug("BEGIN VL UPDATE [%s]", vlocation->vldb.name);
	vlocation->upd_first_svix = vlocation->cell->vl_curr_svix;
	vlocation->upd_curr_svix = vlocation->upd_first_svix;
	vlocation->upd_rej_cnt = 0;
	vlocation->upd_busy_cnt = 0;

	ret = afs_vlocation_update_begin(vlocation);
	if (ret < 0) {
		afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, ret);
		afs_kafstimod_add_timer(&vlocation->upd_timer,
					AFS_VLDB_TIMEOUT);
		afs_put_vlocation(vlocation);
	}

	_leave("");
	return;

 out_unlock2:
	spin_unlock(&afs_vlocation_update_lock);
 out_unlock1:
	spin_unlock(&vlocation->cell->vl_gylock);
	_leave("");
	return;

} /* end afs_vlocation_update_timer() */

/*****************************************************************************/
/*
 * attend to an update operation upon which an event happened
 * - called in kafsasyncd context
 */
static void afs_vlocation_update_attend(struct afs_async_op *op)
{
	struct afs_cache_vlocation vldb;
	struct afs_vlocation *vlocation =
		list_entry(op, struct afs_vlocation, upd_op);
	unsigned tmp;
	int ret;

	_enter("%s", vlocation->vldb.name);

	ret = afs_rxvl_get_entry_by_id_async2(op, &vldb);
	switch (ret) {
	case -EAGAIN:
		_leave(" [unfinished]");
		return;

	case 0:
		_debug("END VL UPDATE: %d\n", ret);
		vlocation->valid = 1;

		_debug("Done VL Lookup: %02x { %08x(%x) %08x(%x) %08x(%x) }",
		       vldb.vidmask,
		       ntohl(vldb.servers[0].s_addr), vldb.srvtmask[0],
		       ntohl(vldb.servers[1].s_addr), vldb.srvtmask[1],
		       ntohl(vldb.servers[2].s_addr), vldb.srvtmask[2]
		       );

		_debug("Vids: %08x %08x %08x",
		       vldb.vid[0], vldb.vid[1], vldb.vid[2]);

		afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, 0);

		down_write(&vlocation->cell->vl_sem);

		/* actually update the cache */
		if (strncmp(vldb.name, vlocation->vldb.name,
			    sizeof(vlocation->vldb.name)) != 0)
			printk("kAFS: name of volume '%s'"
			       " changed to '%s' on server\n",
			       vlocation->vldb.name, vldb.name);

		memcpy(&vlocation->vldb, &vldb, sizeof(vlocation->vldb));

#if 0
		/* TODO update volume entry in local cache */
#endif

		up_write(&vlocation->cell->vl_sem);

		if (ret < 0)
			printk("kAFS: failed to update local cache: %d\n", ret);

		afs_kafstimod_add_timer(&vlocation->upd_timer,
					AFS_VLDB_TIMEOUT);
		afs_put_vlocation(vlocation);
		_leave(" [found]");
		return;

	case -ENOMEDIUM:
		vlocation->upd_rej_cnt++;
		goto try_next;

		/* the server is locked - retry in a very short while */
	case -EBUSY:
		vlocation->upd_busy_cnt++;
		if (vlocation->upd_busy_cnt > 3)
			goto try_next; /* too many retries */

		afs_vlocation_update_abandon(vlocation,
					     AFS_VLUPD_BUSYSLEEP, 0);
		afs_kafstimod_add_timer(&vlocation->upd_timer, HZ / 2);
		afs_put_vlocation(vlocation);
		_leave(" [busy]");
		return;

	case -ENETUNREACH:
	case -EHOSTUNREACH:
	case -ECONNREFUSED:
	case -EREMOTEIO:
		/* record bad vlserver info in the cell too
		 * - TODO: use down_write_trylock() if available
		 */
		if (vlocation->upd_curr_svix == vlocation->cell->vl_curr_svix)
			vlocation->cell->vl_curr_svix =
				vlocation->cell->vl_curr_svix %
				vlocation->cell->vl_naddrs;

	case -EBADRQC:
	case -EINVAL:
	case -EACCES:
	case -EBADMSG:
		goto try_next;

	default:
		goto abandon;
	}

	/* try contacting the next server */
 try_next:
	vlocation->upd_busy_cnt = 0;

	/* discard the server record */
	afs_put_server(vlocation->upd_op.server);
	vlocation->upd_op.server = NULL;

	tmp = vlocation->cell->vl_naddrs;
	if (tmp == 0)
		goto abandon;

	vlocation->upd_curr_svix++;
	if (vlocation->upd_curr_svix >= tmp)
		vlocation->upd_curr_svix = 0;
	if (vlocation->upd_first_svix >= tmp)
		vlocation->upd_first_svix = tmp - 1;

	/* move to the next server */
	if (vlocation->upd_curr_svix != vlocation->upd_first_svix) {
		afs_vlocation_update_begin(vlocation);
		_leave(" [next]");
		return;
	}

	/* run out of servers to try - was the volume rejected? */
	if (vlocation->upd_rej_cnt > 0) {
		printk("kAFS: Active volume no longer valid '%s'\n",
		       vlocation->vldb.name);
		vlocation->valid = 0;
		afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, 0);
		afs_kafstimod_add_timer(&vlocation->upd_timer,
					AFS_VLDB_TIMEOUT);
		afs_put_vlocation(vlocation);
		_leave(" [invalidated]");
		return;
	}

	/* abandon the update */
 abandon:
	afs_vlocation_update_abandon(vlocation, AFS_VLUPD_SLEEP, ret);
	afs_kafstimod_add_timer(&vlocation->upd_timer, HZ * 10);
	afs_put_vlocation(vlocation);
	_leave(" [abandoned]");

} /* end afs_vlocation_update_attend() */

/*****************************************************************************/
/*
 * deal with an update operation being discarded
 * - called in kafsasyncd context when it's dying due to rmmod
 * - the call has already been aborted and put()'d
 */
static void afs_vlocation_update_discard(struct afs_async_op *op)
{
	struct afs_vlocation *vlocation =
		list_entry(op, struct afs_vlocation, upd_op);

	_enter("%s", vlocation->vldb.name);

	afs_put_server(op->server);
	op->server = NULL;

	afs_put_vlocation(vlocation);

	_leave("");
} /* end afs_vlocation_update_discard() */

/*****************************************************************************/
/*
 * match a VLDB record stored in the cache
 * - may also load target from entry
 */
#ifdef AFS_CACHING_SUPPORT
static cachefs_match_val_t afs_vlocation_cache_match(void *target,
						     const void *entry)
{
	const struct afs_cache_vlocation *vldb = entry;
	struct afs_vlocation *vlocation = target;

	_enter("{%s},{%s}", vlocation->vldb.name, vldb->name);

	if (strncmp(vlocation->vldb.name, vldb->name, sizeof(vldb->name)) == 0
	    ) {
		if (!vlocation->valid ||
		    vlocation->vldb.rtime == vldb->rtime
		    ) {
			vlocation->vldb = *vldb;
			vlocation->valid = 1;
			_leave(" = SUCCESS [c->m]");
			return CACHEFS_MATCH_SUCCESS;
		}
		/* need to update cache if cached info differs */
		else if (memcmp(&vlocation->vldb, vldb, sizeof(*vldb)) != 0) {
			/* delete if VIDs for this name differ */
			if (memcmp(&vlocation->vldb.vid,
				   &vldb->vid,
				   sizeof(vldb->vid)) != 0) {
				_leave(" = DELETE");
				return CACHEFS_MATCH_SUCCESS_DELETE;
			}

			_leave(" = UPDATE");
			return CACHEFS_MATCH_SUCCESS_UPDATE;
		}
		else {
			_leave(" = SUCCESS");
			return CACHEFS_MATCH_SUCCESS;
		}
	}

	_leave(" = FAILED");
	return CACHEFS_MATCH_FAILED;
} /* end afs_vlocation_cache_match() */
#endif

/*****************************************************************************/
/*
 * update a VLDB record stored in the cache
 */
#ifdef AFS_CACHING_SUPPORT
static void afs_vlocation_cache_update(void *source, void *entry)
{
	struct afs_cache_vlocation *vldb = entry;
	struct afs_vlocation *vlocation = source;

	_enter("");

	*vldb = vlocation->vldb;

} /* end afs_vlocation_cache_update() */
#endif