aboutsummaryrefslogtreecommitdiff
path: root/fs/ubifs/orphan.c
blob: 3b4b4114f208bfb6bdc1f94803e6d7b5b79bd372 (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
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
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
// SPDX-License-Identifier: GPL-2.0-only
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * Author: Adrian Hunter
 */

#include "ubifs.h"

/*
 * An orphan is an inode number whose inode node has been committed to the index
 * with a link count of zero. That happens when an open file is deleted
 * (unlinked) and then a commit is run. In the normal course of events the inode
 * would be deleted when the file is closed. However in the case of an unclean
 * unmount, orphans need to be accounted for. After an unclean unmount, the
 * orphans' inodes must be deleted which means either scanning the entire index
 * looking for them, or keeping a list on flash somewhere. This unit implements
 * the latter approach.
 *
 * The orphan area is a fixed number of LEBs situated between the LPT area and
 * the main area. The number of orphan area LEBs is specified when the file
 * system is created. The minimum number is 1. The size of the orphan area
 * should be so that it can hold the maximum number of orphans that are expected
 * to ever exist at one time.
 *
 * The number of orphans that can fit in a LEB is:
 *
 *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
 *
 * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
 *
 * Orphans are accumulated in a rb-tree. When an inode's link count drops to
 * zero, the inode number is added to the rb-tree. It is removed from the tree
 * when the inode is deleted.  Any new orphans that are in the orphan tree when
 * the commit is run, are written to the orphan area in 1 or more orphan nodes.
 * If the orphan area is full, it is consolidated to make space.  There is
 * always enough space because validation prevents the user from creating more
 * than the maximum number of orphans allowed.
 */

static int dbg_check_orphans(struct ubifs_info *c);

static struct ubifs_orphan *orphan_add(struct ubifs_info *c, ino_t inum,
				       struct ubifs_orphan *parent_orphan)
{
	struct ubifs_orphan *orphan, *o;
	struct rb_node **p, *parent = NULL;

	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
	if (!orphan)
		return ERR_PTR(-ENOMEM);
	orphan->inum = inum;
	orphan->new = 1;
	INIT_LIST_HEAD(&orphan->child_list);

	spin_lock(&c->orphan_lock);
	if (c->tot_orphans >= c->max_orphans) {
		spin_unlock(&c->orphan_lock);
		kfree(orphan);
		return ERR_PTR(-ENFILE);
	}
	p = &c->orph_tree.rb_node;
	while (*p) {
		parent = *p;
		o = rb_entry(parent, struct ubifs_orphan, rb);
		if (inum < o->inum)
			p = &(*p)->rb_left;
		else if (inum > o->inum)
			p = &(*p)->rb_right;
		else {
			ubifs_err(c, "orphaned twice");
			spin_unlock(&c->orphan_lock);
			kfree(orphan);
			return ERR_PTR(-EINVAL);
		}
	}
	c->tot_orphans += 1;
	c->new_orphans += 1;
	rb_link_node(&orphan->rb, parent, p);
	rb_insert_color(&orphan->rb, &c->orph_tree);
	list_add_tail(&orphan->list, &c->orph_list);
	list_add_tail(&orphan->new_list, &c->orph_new);

	if (parent_orphan) {
		list_add_tail(&orphan->child_list,
			      &parent_orphan->child_list);
	}

	spin_unlock(&c->orphan_lock);
	dbg_gen("ino %lu", (unsigned long)inum);
	return orphan;
}

static struct ubifs_orphan *lookup_orphan(struct ubifs_info *c, ino_t inum)
{
	struct ubifs_orphan *o;
	struct rb_node *p;

	p = c->orph_tree.rb_node;
	while (p) {
		o = rb_entry(p, struct ubifs_orphan, rb);
		if (inum < o->inum)
			p = p->rb_left;
		else if (inum > o->inum)
			p = p->rb_right;
		else {
			return o;
		}
	}
	return NULL;
}

static void __orphan_drop(struct ubifs_info *c, struct ubifs_orphan *o)
{
	rb_erase(&o->rb, &c->orph_tree);
	list_del(&o->list);
	c->tot_orphans -= 1;

	if (o->new) {
		list_del(&o->new_list);
		c->new_orphans -= 1;
	}

	kfree(o);
}

static void orphan_delete(struct ubifs_info *c, struct ubifs_orphan *orph)
{
	if (orph->del) {
		dbg_gen("deleted twice ino %lu", orph->inum);
		return;
	}

	if (orph->cmt) {
		orph->del = 1;
		orph->dnext = c->orph_dnext;
		c->orph_dnext = orph;
		dbg_gen("delete later ino %lu", orph->inum);
		return;
	}

	__orphan_drop(c, orph);
}

/**
 * ubifs_add_orphan - add an orphan.
 * @c: UBIFS file-system description object
 * @inum: orphan inode number
 *
 * Add an orphan. This function is called when an inodes link count drops to
 * zero.
 */
int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
{
	int err = 0;
	ino_t xattr_inum;
	union ubifs_key key;
	struct ubifs_dent_node *xent;
	struct fscrypt_name nm = {0};
	struct ubifs_orphan *xattr_orphan;
	struct ubifs_orphan *orphan;

	orphan = orphan_add(c, inum, NULL);
	if (IS_ERR(orphan))
		return PTR_ERR(orphan);

	lowest_xent_key(c, &key, inum);
	while (1) {
		xent = ubifs_tnc_next_ent(c, &key, &nm);
		if (IS_ERR(xent)) {
			err = PTR_ERR(xent);
			if (err == -ENOENT)
				break;
			return err;
		}

		fname_name(&nm) = xent->name;
		fname_len(&nm) = le16_to_cpu(xent->nlen);
		xattr_inum = le64_to_cpu(xent->inum);

		xattr_orphan = orphan_add(c, xattr_inum, orphan);
		if (IS_ERR(xattr_orphan))
			return PTR_ERR(xattr_orphan);

		key_read(c, &xent->key, &key);
	}

	return 0;
}

/**
 * ubifs_delete_orphan - delete an orphan.
 * @c: UBIFS file-system description object
 * @inum: orphan inode number
 *
 * Delete an orphan. This function is called when an inode is deleted.
 */
void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
{
	struct ubifs_orphan *orph, *child_orph, *tmp_o;

	spin_lock(&c->orphan_lock);

	orph = lookup_orphan(c, inum);
	if (!orph) {
		spin_unlock(&c->orphan_lock);
		ubifs_err(c, "missing orphan ino %lu", (unsigned long)inum);
		dump_stack();

		return;
	}

	list_for_each_entry_safe(child_orph, tmp_o, &orph->child_list, child_list) {
		list_del(&child_orph->child_list);
		orphan_delete(c, child_orph);
	}
	
	orphan_delete(c, orph);

	spin_unlock(&c->orphan_lock);
}

/**
 * ubifs_orphan_start_commit - start commit of orphans.
 * @c: UBIFS file-system description object
 *
 * Start commit of orphans.
 */
int ubifs_orphan_start_commit(struct ubifs_info *c)
{
	struct ubifs_orphan *orphan, **last;

	spin_lock(&c->orphan_lock);
	last = &c->orph_cnext;
	list_for_each_entry(orphan, &c->orph_new, new_list) {
		ubifs_assert(c, orphan->new);
		ubifs_assert(c, !orphan->cmt);
		orphan->new = 0;
		orphan->cmt = 1;
		*last = orphan;
		last = &orphan->cnext;
	}
	*last = NULL;
	c->cmt_orphans = c->new_orphans;
	c->new_orphans = 0;
	dbg_cmt("%d orphans to commit", c->cmt_orphans);
	INIT_LIST_HEAD(&c->orph_new);
	if (c->tot_orphans == 0)
		c->no_orphs = 1;
	else
		c->no_orphs = 0;
	spin_unlock(&c->orphan_lock);
	return 0;
}

/**
 * avail_orphs - calculate available space.
 * @c: UBIFS file-system description object
 *
 * This function returns the number of orphans that can be written in the
 * available space.
 */
static int avail_orphs(struct ubifs_info *c)
{
	int avail_lebs, avail, gap;

	avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
	avail = avail_lebs *
	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
	gap = c->leb_size - c->ohead_offs;
	if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
		avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
	return avail;
}

/**
 * tot_avail_orphs - calculate total space.
 * @c: UBIFS file-system description object
 *
 * This function returns the number of orphans that can be written in half
 * the total space. That leaves half the space for adding new orphans.
 */
static int tot_avail_orphs(struct ubifs_info *c)
{
	int avail_lebs, avail;

	avail_lebs = c->orph_lebs;
	avail = avail_lebs *
	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
	return avail / 2;
}

/**
 * do_write_orph_node - write a node to the orphan head.
 * @c: UBIFS file-system description object
 * @len: length of node
 * @atomic: write atomically
 *
 * This function writes a node to the orphan head from the orphan buffer. If
 * %atomic is not zero, then the write is done atomically. On success, %0 is
 * returned, otherwise a negative error code is returned.
 */
static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
{
	int err = 0;

	if (atomic) {
		ubifs_assert(c, c->ohead_offs == 0);
		ubifs_prepare_node(c, c->orph_buf, len, 1);
		len = ALIGN(len, c->min_io_size);
		err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
	} else {
		if (c->ohead_offs == 0) {
			/* Ensure LEB has been unmapped */
			err = ubifs_leb_unmap(c, c->ohead_lnum);
			if (err)
				return err;
		}
		err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
				       c->ohead_offs);
	}
	return err;
}

/**
 * write_orph_node - write an orphan node.
 * @c: UBIFS file-system description object
 * @atomic: write atomically
 *
 * This function builds an orphan node from the cnext list and writes it to the
 * orphan head. On success, %0 is returned, otherwise a negative error code
 * is returned.
 */
static int write_orph_node(struct ubifs_info *c, int atomic)
{
	struct ubifs_orphan *orphan, *cnext;
	struct ubifs_orph_node *orph;
	int gap, err, len, cnt, i;

	ubifs_assert(c, c->cmt_orphans > 0);
	gap = c->leb_size - c->ohead_offs;
	if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
		c->ohead_lnum += 1;
		c->ohead_offs = 0;
		gap = c->leb_size;
		if (c->ohead_lnum > c->orph_last) {
			/*
			 * We limit the number of orphans so that this should
			 * never happen.
			 */
			ubifs_err(c, "out of space in orphan area");
			return -EINVAL;
		}
	}
	cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
	if (cnt > c->cmt_orphans)
		cnt = c->cmt_orphans;
	len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
	ubifs_assert(c, c->orph_buf);
	orph = c->orph_buf;
	orph->ch.node_type = UBIFS_ORPH_NODE;
	spin_lock(&c->orphan_lock);
	cnext = c->orph_cnext;
	for (i = 0; i < cnt; i++) {
		orphan = cnext;
		ubifs_assert(c, orphan->cmt);
		orph->inos[i] = cpu_to_le64(orphan->inum);
		orphan->cmt = 0;
		cnext = orphan->cnext;
		orphan->cnext = NULL;
	}
	c->orph_cnext = cnext;
	c->cmt_orphans -= cnt;
	spin_unlock(&c->orphan_lock);
	if (c->cmt_orphans)
		orph->cmt_no = cpu_to_le64(c->cmt_no);
	else
		/* Mark the last node of the commit */
		orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
	ubifs_assert(c, c->ohead_offs + len <= c->leb_size);
	ubifs_assert(c, c->ohead_lnum >= c->orph_first);
	ubifs_assert(c, c->ohead_lnum <= c->orph_last);
	err = do_write_orph_node(c, len, atomic);
	c->ohead_offs += ALIGN(len, c->min_io_size);
	c->ohead_offs = ALIGN(c->ohead_offs, 8);
	return err;
}

/**
 * write_orph_nodes - write orphan nodes until there are no more to commit.
 * @c: UBIFS file-system description object
 * @atomic: write atomically
 *
 * This function writes orphan nodes for all the orphans to commit. On success,
 * %0 is returned, otherwise a negative error code is returned.
 */
static int write_orph_nodes(struct ubifs_info *c, int atomic)
{
	int err;

	while (c->cmt_orphans > 0) {
		err = write_orph_node(c, atomic);
		if (err)
			return err;
	}
	if (atomic) {
		int lnum;

		/* Unmap any unused LEBs after consolidation */
		for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
			err = ubifs_leb_unmap(c, lnum);
			if (err)
				return err;
		}
	}
	return 0;
}

/**
 * consolidate - consolidate the orphan area.
 * @c: UBIFS file-system description object
 *
 * This function enables consolidation by putting all the orphans into the list
 * to commit. The list is in the order that the orphans were added, and the
 * LEBs are written atomically in order, so at no time can orphans be lost by
 * an unclean unmount.
 *
 * This function returns %0 on success and a negative error code on failure.
 */
static int consolidate(struct ubifs_info *c)
{
	int tot_avail = tot_avail_orphs(c), err = 0;

	spin_lock(&c->orphan_lock);
	dbg_cmt("there is space for %d orphans and there are %d",
		tot_avail, c->tot_orphans);
	if (c->tot_orphans - c->new_orphans <= tot_avail) {
		struct ubifs_orphan *orphan, **last;
		int cnt = 0;

		/* Change the cnext list to include all non-new orphans */
		last = &c->orph_cnext;
		list_for_each_entry(orphan, &c->orph_list, list) {
			if (orphan->new)
				continue;
			orphan->cmt = 1;
			*last = orphan;
			last = &orphan->cnext;
			cnt += 1;
		}
		*last = NULL;
		ubifs_assert(c, cnt == c->tot_orphans - c->new_orphans);
		c->cmt_orphans = cnt;
		c->ohead_lnum = c->orph_first;
		c->ohead_offs = 0;
	} else {
		/*
		 * We limit the number of orphans so that this should
		 * never happen.
		 */
		ubifs_err(c, "out of space in orphan area");
		err = -EINVAL;
	}
	spin_unlock(&c->orphan_lock);
	return err;
}

/**
 * commit_orphans - commit orphans.
 * @c: UBIFS file-system description object
 *
 * This function commits orphans to flash. On success, %0 is returned,
 * otherwise a negative error code is returned.
 */
static int commit_orphans(struct ubifs_info *c)
{
	int avail, atomic = 0, err;

	ubifs_assert(c, c->cmt_orphans > 0);
	avail = avail_orphs(c);
	if (avail < c->cmt_orphans) {
		/* Not enough space to write new orphans, so consolidate */
		err = consolidate(c);
		if (err)
			return err;
		atomic = 1;
	}
	err = write_orph_nodes(c, atomic);
	return err;
}

/**
 * erase_deleted - erase the orphans marked for deletion.
 * @c: UBIFS file-system description object
 *
 * During commit, the orphans being committed cannot be deleted, so they are
 * marked for deletion and deleted by this function. Also, the recovery
 * adds killed orphans to the deletion list, and therefore they are deleted
 * here too.
 */
static void erase_deleted(struct ubifs_info *c)
{
	struct ubifs_orphan *orphan, *dnext;

	spin_lock(&c->orphan_lock);
	dnext = c->orph_dnext;
	while (dnext) {
		orphan = dnext;
		dnext = orphan->dnext;
		ubifs_assert(c, !orphan->new);
		ubifs_assert(c, orphan->del);
		rb_erase(&orphan->rb, &c->orph_tree);
		list_del(&orphan->list);
		c->tot_orphans -= 1;
		dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
		kfree(orphan);
	}
	c->orph_dnext = NULL;
	spin_unlock(&c->orphan_lock);
}

/**
 * ubifs_orphan_end_commit - end commit of orphans.
 * @c: UBIFS file-system description object
 *
 * End commit of orphans.
 */
int ubifs_orphan_end_commit(struct ubifs_info *c)
{
	int err;

	if (c->cmt_orphans != 0) {
		err = commit_orphans(c);
		if (err)
			return err;
	}
	erase_deleted(c);
	err = dbg_check_orphans(c);
	return err;
}

/**
 * ubifs_clear_orphans - erase all LEBs used for orphans.
 * @c: UBIFS file-system description object
 *
 * If recovery is not required, then the orphans from the previous session
 * are not needed. This function locates the LEBs used to record
 * orphans, and un-maps them.
 */
int ubifs_clear_orphans(struct ubifs_info *c)
{
	int lnum, err;

	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
		err = ubifs_leb_unmap(c, lnum);
		if (err)
			return err;
	}
	c->ohead_lnum = c->orph_first;
	c->ohead_offs = 0;
	return 0;
}

/**
 * insert_dead_orphan - insert an orphan.
 * @c: UBIFS file-system description object
 * @inum: orphan inode number
 *
 * This function is a helper to the 'do_kill_orphans()' function. The orphan
 * must be kept until the next commit, so it is added to the rb-tree and the
 * deletion list.
 */
static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
{
	struct ubifs_orphan *orphan, *o;
	struct rb_node **p, *parent = NULL;

	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_KERNEL);
	if (!orphan)
		return -ENOMEM;
	orphan->inum = inum;

	p = &c->orph_tree.rb_node;
	while (*p) {
		parent = *p;
		o = rb_entry(parent, struct ubifs_orphan, rb);
		if (inum < o->inum)
			p = &(*p)->rb_left;
		else if (inum > o->inum)
			p = &(*p)->rb_right;
		else {
			/* Already added - no problem */
			kfree(orphan);
			return 0;
		}
	}
	c->tot_orphans += 1;
	rb_link_node(&orphan->rb, parent, p);
	rb_insert_color(&orphan->rb, &c->orph_tree);
	list_add_tail(&orphan->list, &c->orph_list);
	orphan->del = 1;
	orphan->dnext = c->orph_dnext;
	c->orph_dnext = orphan;
	dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
		c->new_orphans, c->tot_orphans);
	return 0;
}

/**
 * do_kill_orphans - remove orphan inodes from the index.
 * @c: UBIFS file-system description object
 * @sleb: scanned LEB
 * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
 * @outofdate: whether the LEB is out of date is returned here
 * @last_flagged: whether the end orphan node is encountered
 *
 * This function is a helper to the 'kill_orphans()' function. It goes through
 * every orphan node in a LEB and for every inode number recorded, removes
 * all keys for that inode from the TNC.
 */
static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
			   unsigned long long *last_cmt_no, int *outofdate,
			   int *last_flagged)
{
	struct ubifs_scan_node *snod;
	struct ubifs_orph_node *orph;
	struct ubifs_ino_node *ino = NULL;
	unsigned long long cmt_no;
	ino_t inum;
	int i, n, err, first = 1;

	list_for_each_entry(snod, &sleb->nodes, list) {
		if (snod->type != UBIFS_ORPH_NODE) {
			ubifs_err(c, "invalid node type %d in orphan area at %d:%d",
				  snod->type, sleb->lnum, snod->offs);
			ubifs_dump_node(c, snod->node);
			return -EINVAL;
		}

		orph = snod->node;

		/* Check commit number */
		cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
		/*
		 * The commit number on the master node may be less, because
		 * of a failed commit. If there are several failed commits in a
		 * row, the commit number written on orphan nodes will continue
		 * to increase (because the commit number is adjusted here) even
		 * though the commit number on the master node stays the same
		 * because the master node has not been re-written.
		 */
		if (cmt_no > c->cmt_no)
			c->cmt_no = cmt_no;
		if (cmt_no < *last_cmt_no && *last_flagged) {
			/*
			 * The last orphan node had a higher commit number and
			 * was flagged as the last written for that commit
			 * number. That makes this orphan node, out of date.
			 */
			if (!first) {
				ubifs_err(c, "out of order commit number %llu in orphan node at %d:%d",
					  cmt_no, sleb->lnum, snod->offs);
				ubifs_dump_node(c, snod->node);
				return -EINVAL;
			}
			dbg_rcvry("out of date LEB %d", sleb->lnum);
			*outofdate = 1;
			return 0;
		}

		if (first)
			first = 0;

		ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
		if (!ino)
			return -ENOMEM;

		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
		for (i = 0; i < n; i++) {
			union ubifs_key key1, key2;

			inum = le64_to_cpu(orph->inos[i]);

			ino_key_init(c, &key1, inum);
			err = ubifs_tnc_lookup(c, &key1, ino);
			if (err)
				goto out_free;

			/*
			 * Check whether an inode can really get deleted.
			 * linkat() with O_TMPFILE allows rebirth of an inode.
			 */
			if (ino->nlink == 0) {
				dbg_rcvry("deleting orphaned inode %lu",
					  (unsigned long)inum);

				lowest_ino_key(c, &key1, inum);
				highest_ino_key(c, &key2, inum);

				err = ubifs_tnc_remove_range(c, &key1, &key2);
				if (err)
					goto out_ro;
			}

			err = insert_dead_orphan(c, inum);
			if (err)
				goto out_free;
		}

		*last_cmt_no = cmt_no;
		if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
			dbg_rcvry("last orph node for commit %llu at %d:%d",
				  cmt_no, sleb->lnum, snod->offs);
			*last_flagged = 1;
		} else
			*last_flagged = 0;
	}

	err = 0;
out_free:
	kfree(ino);
	return err;

out_ro:
	ubifs_ro_mode(c, err);
	kfree(ino);
	return err;
}

/**
 * kill_orphans - remove all orphan inodes from the index.
 * @c: UBIFS file-system description object
 *
 * If recovery is required, then orphan inodes recorded during the previous
 * session (which ended with an unclean unmount) must be deleted from the index.
 * This is done by updating the TNC, but since the index is not updated until
 * the next commit, the LEBs where the orphan information is recorded are not
 * erased until the next commit.
 */
static int kill_orphans(struct ubifs_info *c)
{
	unsigned long long last_cmt_no = 0;
	int lnum, err = 0, outofdate = 0, last_flagged = 0;

	c->ohead_lnum = c->orph_first;
	c->ohead_offs = 0;
	/* Check no-orphans flag and skip this if no orphans */
	if (c->no_orphs) {
		dbg_rcvry("no orphans");
		return 0;
	}
	/*
	 * Orph nodes always start at c->orph_first and are written to each
	 * successive LEB in turn. Generally unused LEBs will have been unmapped
	 * but may contain out of date orphan nodes if the unmap didn't go
	 * through. In addition, the last orphan node written for each commit is
	 * marked (top bit of orph->cmt_no is set to 1). It is possible that
	 * there are orphan nodes from the next commit (i.e. the commit did not
	 * complete successfully). In that case, no orphans will have been lost
	 * due to the way that orphans are written, and any orphans added will
	 * be valid orphans anyway and so can be deleted.
	 */
	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
		struct ubifs_scan_leb *sleb;

		dbg_rcvry("LEB %d", lnum);
		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
		if (IS_ERR(sleb)) {
			if (PTR_ERR(sleb) == -EUCLEAN)
				sleb = ubifs_recover_leb(c, lnum, 0,
							 c->sbuf, -1);
			if (IS_ERR(sleb)) {
				err = PTR_ERR(sleb);
				break;
			}
		}
		err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
				      &last_flagged);
		if (err || outofdate) {
			ubifs_scan_destroy(sleb);
			break;
		}
		if (sleb->endpt) {
			c->ohead_lnum = lnum;
			c->ohead_offs = sleb->endpt;
		}
		ubifs_scan_destroy(sleb);
	}
	return err;
}

/**
 * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
 * @c: UBIFS file-system description object
 * @unclean: indicates recovery from unclean unmount
 * @read_only: indicates read only mount
 *
 * This function is called when mounting to erase orphans from the previous
 * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
 * orphans are deleted.
 */
int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
{
	int err = 0;

	c->max_orphans = tot_avail_orphs(c);

	if (!read_only) {
		c->orph_buf = vmalloc(c->leb_size);
		if (!c->orph_buf)
			return -ENOMEM;
	}

	if (unclean)
		err = kill_orphans(c);
	else if (!read_only)
		err = ubifs_clear_orphans(c);

	return err;
}

/*
 * Everything below is related to debugging.
 */

struct check_orphan {
	struct rb_node rb;
	ino_t inum;
};

struct check_info {
	unsigned long last_ino;
	unsigned long tot_inos;
	unsigned long missing;
	unsigned long long leaf_cnt;
	struct ubifs_ino_node *node;
	struct rb_root root;
};

static bool dbg_find_orphan(struct ubifs_info *c, ino_t inum)
{
	bool found = false;

	spin_lock(&c->orphan_lock);
	found = !!lookup_orphan(c, inum);
	spin_unlock(&c->orphan_lock);

	return found;
}

static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
{
	struct check_orphan *orphan, *o;
	struct rb_node **p, *parent = NULL;

	orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
	if (!orphan)
		return -ENOMEM;
	orphan->inum = inum;

	p = &root->rb_node;
	while (*p) {
		parent = *p;
		o = rb_entry(parent, struct check_orphan, rb);
		if (inum < o->inum)
			p = &(*p)->rb_left;
		else if (inum > o->inum)
			p = &(*p)->rb_right;
		else {
			kfree(orphan);
			return 0;
		}
	}
	rb_link_node(&orphan->rb, parent, p);
	rb_insert_color(&orphan->rb, root);
	return 0;
}

static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
{
	struct check_orphan *o;
	struct rb_node *p;

	p = root->rb_node;
	while (p) {
		o = rb_entry(p, struct check_orphan, rb);
		if (inum < o->inum)
			p = p->rb_left;
		else if (inum > o->inum)
			p = p->rb_right;
		else
			return 1;
	}
	return 0;
}

static void dbg_free_check_tree(struct rb_root *root)
{
	struct check_orphan *o, *n;

	rbtree_postorder_for_each_entry_safe(o, n, root, rb)
		kfree(o);
}

static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
			    void *priv)
{
	struct check_info *ci = priv;
	ino_t inum;
	int err;

	inum = key_inum(c, &zbr->key);
	if (inum != ci->last_ino) {
		/* Lowest node type is the inode node, so it comes first */
		if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
			ubifs_err(c, "found orphan node ino %lu, type %d",
				  (unsigned long)inum, key_type(c, &zbr->key));
		ci->last_ino = inum;
		ci->tot_inos += 1;
		err = ubifs_tnc_read_node(c, zbr, ci->node);
		if (err) {
			ubifs_err(c, "node read failed, error %d", err);
			return err;
		}
		if (ci->node->nlink == 0)
			/* Must be recorded as an orphan */
			if (!dbg_find_check_orphan(&ci->root, inum) &&
			    !dbg_find_orphan(c, inum)) {
				ubifs_err(c, "missing orphan, ino %lu",
					  (unsigned long)inum);
				ci->missing += 1;
			}
	}
	ci->leaf_cnt += 1;
	return 0;
}

static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
{
	struct ubifs_scan_node *snod;
	struct ubifs_orph_node *orph;
	ino_t inum;
	int i, n, err;

	list_for_each_entry(snod, &sleb->nodes, list) {
		cond_resched();
		if (snod->type != UBIFS_ORPH_NODE)
			continue;
		orph = snod->node;
		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
		for (i = 0; i < n; i++) {
			inum = le64_to_cpu(orph->inos[i]);
			err = dbg_ins_check_orphan(&ci->root, inum);
			if (err)
				return err;
		}
	}
	return 0;
}

static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
{
	int lnum, err = 0;
	void *buf;

	/* Check no-orphans flag and skip this if no orphans */
	if (c->no_orphs)
		return 0;

	buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
	if (!buf) {
		ubifs_err(c, "cannot allocate memory to check orphans");
		return 0;
	}

	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
		struct ubifs_scan_leb *sleb;

		sleb = ubifs_scan(c, lnum, 0, buf, 0);
		if (IS_ERR(sleb)) {
			err = PTR_ERR(sleb);
			break;
		}

		err = dbg_read_orphans(ci, sleb);
		ubifs_scan_destroy(sleb);
		if (err)
			break;
	}

	vfree(buf);
	return err;
}

static int dbg_check_orphans(struct ubifs_info *c)
{
	struct check_info ci;
	int err;

	if (!dbg_is_chk_orph(c))
		return 0;

	ci.last_ino = 0;
	ci.tot_inos = 0;
	ci.missing  = 0;
	ci.leaf_cnt = 0;
	ci.root = RB_ROOT;
	ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
	if (!ci.node) {
		ubifs_err(c, "out of memory");
		return -ENOMEM;
	}

	err = dbg_scan_orphans(c, &ci);
	if (err)
		goto out;

	err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
	if (err) {
		ubifs_err(c, "cannot scan TNC, error %d", err);
		goto out;
	}

	if (ci.missing) {
		ubifs_err(c, "%lu missing orphan(s)", ci.missing);
		err = -EINVAL;
		goto out;
	}

	dbg_cmt("last inode number is %lu", ci.last_ino);
	dbg_cmt("total number of inodes is %lu", ci.tot_inos);
	dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);

out:
	dbg_free_check_tree(&ci.root);
	kfree(ci.node);
	return err;
}