aboutsummaryrefslogtreecommitdiffstats
path: root/fs/jffs2/nodelist.c
blob: 007d52f394dd800522f2210e78bc470d17b1a1ef (plain) (blame)
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
1041
1042
1043
1044
1045
1046
1047
1048
1049
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: nodelist.c,v 1.107 2005/08/03 09:26:46 dedekind Exp $
 *
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/mtd/mtd.h>
#include <linux/rbtree.h>
#include <linux/crc32.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include "nodelist.h"

void jffs2_add_fd_to_list(struct jffs2_sb_info *c, struct jffs2_full_dirent *new, struct jffs2_full_dirent **list)
{
	struct jffs2_full_dirent **prev = list;
	
	JFFS2_DBG_DENTLIST("add dirent \"%s\", ino #%u\n", new->name, new->ino);

	while ((*prev) && (*prev)->nhash <= new->nhash) {
		if ((*prev)->nhash == new->nhash && !strcmp((*prev)->name, new->name)) {
			/* Duplicate. Free one */
			if (new->version < (*prev)->version) {
				JFFS2_DBG_DENTLIST("Eep! Marking new dirent node is obsolete, old is \"%s\", ino #%u\n",
					(*prev)->name, (*prev)->ino);
				jffs2_mark_node_obsolete(c, new->raw);
				jffs2_free_full_dirent(new);
			} else {
				JFFS2_DBG_DENTLIST("marking old dirent \"%s\", ino #%u bsolete\n",
					(*prev)->name, (*prev)->ino);
				new->next = (*prev)->next;
				jffs2_mark_node_obsolete(c, ((*prev)->raw));
				jffs2_free_full_dirent(*prev);
				*prev = new;
			}
			return;
		}
		prev = &((*prev)->next);
	}
	new->next = *prev;
	*prev = new;
}

void jffs2_truncate_fragtree(struct jffs2_sb_info *c, struct rb_root *list, uint32_t size)
{
	struct jffs2_node_frag *frag = jffs2_lookup_node_frag(list, size);

	JFFS2_DBG_FRAGTREE("truncating fragtree to 0x%08x bytes\n", size);

	/* We know frag->ofs <= size. That's what lookup does for us */
	if (frag && frag->ofs != size) {
		if (frag->ofs+frag->size > size) {
			frag->size = size - frag->ofs;
		}
		frag = frag_next(frag);
	}
	while (frag && frag->ofs >= size) {
		struct jffs2_node_frag *next = frag_next(frag);

		frag_erase(frag, list);
		jffs2_obsolete_node_frag(c, frag);
		frag = next;
	}

	if (size == 0)
		return;

	/* 
	 * If the last fragment starts at the RAM page boundary, it is
	 * REF_PRISTINE irrespective of its size.
	 */
	frag = frag_last(list);
	if ((frag->ofs & (PAGE_CACHE_SIZE - 1)) == 0) {
		JFFS2_DBG_FRAGTREE2("marking the last fragment 0x%08x-0x%08x REF_PRISTINE.\n",
			frag->ofs, frag->ofs + frag->size); 
		frag->node->raw->flash_offset = ref_offset(frag->node->raw) | REF_PRISTINE;
	}
}

void jffs2_obsolete_node_frag(struct jffs2_sb_info *c, struct jffs2_node_frag *this)
{
	if (this->node) {
		this->node->frags--;
		if (!this->node->frags) {
			/* The node has no valid frags left. It's totally obsoleted */
			JFFS2_DBG_FRAGTREE2("marking old node @0x%08x (0x%04x-0x%04x) obsolete\n",
				ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size);
			jffs2_mark_node_obsolete(c, this->node->raw);
			jffs2_free_full_dnode(this->node);
		} else {
			JFFS2_DBG_FRAGTREE2("marking old node @0x%08x (0x%04x-0x%04x) REF_NORMAL. frags is %d\n",
				ref_offset(this->node->raw), this->node->ofs, this->node->ofs+this->node->size, this->node->frags);
			mark_ref_normal(this->node->raw);
		}
		
	}
	jffs2_free_node_frag(this);
}

static void jffs2_fragtree_insert(struct jffs2_node_frag *newfrag, struct jffs2_node_frag *base)
{
	struct rb_node *parent = &base->rb;
	struct rb_node **link = &parent;

	JFFS2_DBG_FRAGTREE2("insert frag (0x%04x-0x%04x)\n", newfrag->ofs, newfrag->ofs + newfrag->size);

	while (*link) {
		parent = *link;
		base = rb_entry(parent, struct jffs2_node_frag, rb);
	
		if (newfrag->ofs > base->ofs)
			link = &base->rb.rb_right;
		else if (newfrag->ofs < base->ofs)
			link = &base->rb.rb_left;
		else {
			JFFS2_ERROR("duplicate frag at %08x (%p,%p)\n", newfrag->ofs, newfrag, base);
			BUG();
		}
	}

	rb_link_node(&newfrag->rb, &base->rb, link);
}

/*
 * Allocate and initializes a new fragment.
 */
static inline struct jffs2_node_frag * new_fragment(struct jffs2_full_dnode *fn, uint32_t ofs, uint32_t size)
{
	struct jffs2_node_frag *newfrag;
	
	newfrag = jffs2_alloc_node_frag();
	if (likely(newfrag)) {
		newfrag->ofs = ofs;
		newfrag->size = size;
		newfrag->node = fn;
	} else {
		JFFS2_ERROR("cannot allocate a jffs2_node_frag object\n");
	}

	return newfrag;
}

/*
 * Called when there is no overlapping fragment exist. Inserts a hole before the new
 * fragment and inserts the new fragment to the fragtree.
 */
static int no_overlapping_node(struct jffs2_sb_info *c, struct rb_root *root,
		 	       struct jffs2_node_frag *newfrag,
			       struct jffs2_node_frag *this, uint32_t lastend)
{
	if (lastend < newfrag->node->ofs) {
		/* put a hole in before the new fragment */
		struct jffs2_node_frag *holefrag;

		holefrag= new_fragment(NULL, lastend, newfrag->node->ofs - lastend);
		if (unlikely(!holefrag)) {
			jffs2_free_node_frag(newfrag);
			return -ENOMEM;
		}

		if (this) {
			/* By definition, the 'this' node has no right-hand child, 
			   because there are no frags with offset greater than it.
			   So that's where we want to put the hole */
			JFFS2_DBG_FRAGTREE2("add hole frag %#04x-%#04x on the right of the new frag.\n",
				holefrag->ofs, holefrag->ofs + holefrag->size);
			rb_link_node(&holefrag->rb, &this->rb, &this->rb.rb_right);
		} else {
			JFFS2_DBG_FRAGTREE2("Add hole frag %#04x-%#04x to the root of the tree.\n",
				holefrag->ofs, holefrag->ofs + holefrag->size);
			rb_link_node(&holefrag->rb, NULL, &root->rb_node);
		}
		rb_insert_color(&holefrag->rb, root);
		this = holefrag;
	}
	
	if (this) {
		/* By definition, the 'this' node has no right-hand child, 
		   because there are no frags with offset greater than it.
		   So that's where we want to put new fragment */
		JFFS2_DBG_FRAGTREE2("add the new node at the right\n");
		rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);			
	} else {
		JFFS2_DBG_FRAGTREE2("insert the new node at the root of the tree\n");
		rb_link_node(&newfrag->rb, NULL, &root->rb_node);
	}
	rb_insert_color(&newfrag->rb, root);

	return 0;
}

/* Doesn't set inode->i_size */
static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *root, struct jffs2_node_frag *newfrag)
{
	struct jffs2_node_frag *this;
	uint32_t lastend;

	/* Skip all the nodes which are completed before this one starts */
	this = jffs2_lookup_node_frag(root, newfrag->node->ofs);

	if (this) {
		JFFS2_DBG_FRAGTREE2("lookup gave frag 0x%04x-0x%04x; phys 0x%08x (*%p)\n",
			  this->ofs, this->ofs+this->size, this->node?(ref_offset(this->node->raw)):0xffffffff, this);
		lastend = this->ofs + this->size;
	} else {
		JFFS2_DBG_FRAGTREE2("lookup gave no frag\n");
		lastend = 0;
	}
			  
	/* See if we ran off the end of the fragtree */
	if (lastend <= newfrag->ofs) {
		/* We did */

		/* Check if 'this' node was on the same page as the new node.
		   If so, both 'this' and the new node get marked REF_NORMAL so
		   the GC can take a look.
		*/
		if (lastend && (lastend-1) >> PAGE_CACHE_SHIFT == newfrag->ofs >> PAGE_CACHE_SHIFT) {
			if (this->node)
				mark_ref_normal(this->node->raw);
			mark_ref_normal(newfrag->node->raw);
		}

		return no_overlapping_node(c, root, newfrag, this, lastend);
	}

	if (this->node)
		JFFS2_DBG_FRAGTREE2("dealing with frag %u-%u, phys %#08x(%d).\n",
		this->ofs, this->ofs + this->size,
		ref_offset(this->node->raw), ref_flags(this->node->raw));
	else
		JFFS2_DBG_FRAGTREE2("dealing with hole frag %u-%u.\n",
		this->ofs, this->ofs + this->size);

	/* OK. 'this' is pointing at the first frag that newfrag->ofs at least partially obsoletes,
	 * - i.e. newfrag->ofs < this->ofs+this->size && newfrag->ofs >= this->ofs  
	 */
	if (newfrag->ofs > this->ofs) {
		/* This node isn't completely obsoleted. The start of it remains valid */

		/* Mark the new node and the partially covered node REF_NORMAL -- let
		   the GC take a look at them */
		mark_ref_normal(newfrag->node->raw);
		if (this->node)
			mark_ref_normal(this->node->raw);

		if (this->ofs + this->size > newfrag->ofs + newfrag->size) {
			/* The new node splits 'this' frag into two */
			struct jffs2_node_frag *newfrag2;

			if (this->node)
				JFFS2_DBG_FRAGTREE2("split old frag 0x%04x-0x%04x, phys 0x%08x\n",
					this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
			else 
				JFFS2_DBG_FRAGTREE2("split old hole frag 0x%04x-0x%04x\n",
					this->ofs, this->ofs+this->size, ref_offset(this->node->raw));
			
			/* New second frag pointing to this's node */
			newfrag2 = new_fragment(this->node, newfrag->ofs + newfrag->size,
						this->ofs + this->size - newfrag->ofs - newfrag->size);
			if (unlikely(!newfrag2))
				return -ENOMEM;
			if (this->node)
				this->node->frags++;

			/* Adjust size of original 'this' */
			this->size = newfrag->ofs - this->ofs;

			/* Now, we know there's no node with offset
			   greater than this->ofs but smaller than
			   newfrag2->ofs or newfrag->ofs, for obvious
			   reasons. So we can do a tree insert from
			   'this' to insert newfrag, and a tree insert
			   from newfrag to insert newfrag2. */
			jffs2_fragtree_insert(newfrag, this);
			rb_insert_color(&newfrag->rb, root);
			
			jffs2_fragtree_insert(newfrag2, newfrag);
			rb_insert_color(&newfrag2->rb, root);
			
			return 0;
		}
		/* New node just reduces 'this' frag in size, doesn't split it */
		this->size = newfrag->ofs - this->ofs;

		/* Again, we know it lives down here in the tree */
		jffs2_fragtree_insert(newfrag, this);
		rb_insert_color(&newfrag->rb, root);
	} else {
		/* New frag starts at the same point as 'this' used to. Replace 
		   it in the tree without doing a delete and insertion */
		JFFS2_DBG_FRAGTREE2("inserting newfrag (*%p),%d-%d in before 'this' (*%p),%d-%d\n",
			  newfrag, newfrag->ofs, newfrag->ofs+newfrag->size, this, this->ofs, this->ofs+this->size);
	
		rb_replace_node(&this->rb, &newfrag->rb, root);
		
		if (newfrag->ofs + newfrag->size >= this->ofs+this->size) {
			JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x)\n", this, this->ofs, this->ofs+this->size);
			jffs2_obsolete_node_frag(c, this);
		} else {
			this->ofs += newfrag->size;
			this->size -= newfrag->size;

			jffs2_fragtree_insert(this, newfrag);
			rb_insert_color(&this->rb, root);
			return 0;
		}
	}
	/* OK, now we have newfrag added in the correct place in the tree, but
	   frag_next(newfrag) may be a fragment which is overlapped by it 
	*/
	while ((this = frag_next(newfrag)) && newfrag->ofs + newfrag->size >= this->ofs + this->size) {
		/* 'this' frag is obsoleted completely. */
		JFFS2_DBG_FRAGTREE2("obsoleting node frag %p (%x-%x) and removing from tree\n",
			this, this->ofs, this->ofs+this->size);
		rb_erase(&this->rb, root);
		jffs2_obsolete_node_frag(c, this);
	}
	/* Now we're pointing at the first frag which isn't totally obsoleted by 
	   the new frag */

	if (!this || newfrag->ofs + newfrag->size == this->ofs)
		return 0;

	/* Still some overlap but we don't need to move it in the tree */
	this->size = (this->ofs + this->size) - (newfrag->ofs + newfrag->size);
	this->ofs = newfrag->ofs + newfrag->size;

	/* And mark them REF_NORMAL so the GC takes a look at them */
	if (this->node)
		mark_ref_normal(this->node->raw);
	mark_ref_normal(newfrag->node->raw);

	return 0;
}

/* 
 * Given an inode, probably with existing tree of fragments, add the new node
 * to the fragment tree.
 */
int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_full_dnode *fn)
{
	int ret;
	struct jffs2_node_frag *newfrag;

	if (unlikely(!fn->size))
		return 0;

	newfrag = new_fragment(fn, fn->ofs, fn->size);
	if (unlikely(!newfrag))
		return -ENOMEM;
	newfrag->node->frags = 1;

	JFFS2_DBG_FRAGTREE("adding node %#04x-%#04x @0x%08x on flash, newfrag *%p\n",
		  fn->ofs, fn->ofs+fn->size, ref_offset(fn->raw), newfrag);
	
	ret = jffs2_add_frag_to_fragtree(c, &f->fragtree, newfrag);
	if (unlikely(ret))
		return ret;

	/* If we now share a page with other nodes, mark either previous
	   or next node REF_NORMAL, as appropriate.  */
	if (newfrag->ofs & (PAGE_CACHE_SIZE-1)) {
		struct jffs2_node_frag *prev = frag_prev(newfrag);

		mark_ref_normal(fn->raw);
		/* If we don't start at zero there's _always_ a previous */	
		if (prev->node)
			mark_ref_normal(prev->node->raw);
	}

	if ((newfrag->ofs+newfrag->size) & (PAGE_CACHE_SIZE-1)) {
		struct jffs2_node_frag *next = frag_next(newfrag);
		
		if (next) {
			mark_ref_normal(fn->raw);
			if (next->node)
				mark_ref_normal(next->node->raw);
		}
	}
	jffs2_dbg_fragtree_paranoia_check_nolock(f);

	return 0;
}

/*
 * Check the data CRC of the node.
 *
 * Returns: 0 if the data CRC is correct;
 * 	    1 - if incorrect;
 *	    error code if an error occured.
 */
static int check_node_data(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
{
	struct jffs2_raw_node_ref *ref = tn->fn->raw;
	int err = 0, pointed = 0;
	struct jffs2_eraseblock *jeb;
	unsigned char *buffer;
	uint32_t crc, ofs, retlen, len;

	BUG_ON(tn->csize == 0);

	/* Calculate how many bytes were already checked */
	ofs = ref_offset(ref) + sizeof(struct jffs2_raw_inode);
	len = ofs - (ofs & (PAGE_CACHE_SIZE - 1));
	len = c->wbuf_pagesize - len;

	if (len >= tn->csize) {
		JFFS2_DBG_READINODE("no need to check node at %#08x, data length %u, data starts at %#08x - it has already been checked.\n",
			ref_offset(ref), tn->csize, ofs);
		goto adj_acc;
	}
	
	ofs += len;
	len = tn->csize - len;
	
	JFFS2_DBG_READINODE("check node at %#08x, data length %u, partial CRC %#08x, correct CRC %#08x, data starts at %#08x, start checking from %#08x - %u bytes.\n",
		ref_offset(ref), tn->csize, tn->partial_crc, tn->data_crc, ofs - len, ofs, len);
	
#ifndef __ECOS
	/* TODO: instead, incapsulate point() stuff to jffs2_flash_read(),
	 * adding and jffs2_flash_read_end() interface. */
	if (c->mtd->point) {
		err = c->mtd->point(c->mtd, ofs, len, &retlen, &buffer);
		if (!err && retlen < tn->csize) {
			JFFS2_WARNING("MTD point returned len too short: %u instead of %u.\n", retlen, tn->csize);
			c->mtd->unpoint(c->mtd, buffer, ofs, len);
		} else if (err)
			JFFS2_WARNING("MTD point failed: error code %d.\n", err);
		else
			pointed = 1; /* succefully pointed to device */
	}
#endif
	
	if (!pointed) {
		buffer = kmalloc(len, GFP_KERNEL);
		if (unlikely(!buffer))
			return -ENOMEM;
			
		/* TODO: this is very frequent pattern, make it a separate
		 * routine */
		err = jffs2_flash_read(c, ofs, len, &retlen, buffer);
		if (err) {
			JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ofs, err);
			goto free_out;
		}
			
		if (retlen != len) {
			JFFS2_ERROR("short read at %#08x: %d instead of %d.\n", ofs, retlen, len);
			err = -EIO;
			goto free_out;
		}
	}

	/* Continue calculating CRC */
	crc = crc32(tn->partial_crc, buffer, len);
	if(!pointed)
		kfree(buffer);
#ifndef __ECOS
	else
		c->mtd->unpoint(c->mtd, buffer, ofs, len);
#endif

	if (crc != tn->data_crc) {
		JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
			ofs, tn->data_crc, crc);
		return 1;
	}

adj_acc:
	jeb = &c->blocks[ref->flash_offset / c->sector_size];
	len = ref_totlen(c, jeb, ref);

	/* 
	 * Mark the node as having been checked and fix the
	 * accounting accordingly.
	 */
	spin_lock(&c->erase_completion_lock);
	jeb->used_size += len;
	jeb->unchecked_size -= len;
	c->used_size += len;
	c->unchecked_size -= len;
	spin_unlock(&c->erase_completion_lock);

	return 0;

free_out:
	if(!pointed)
		kfree(buffer);
#ifndef __ECOS
	else
		c->mtd->unpoint(c->mtd, buffer, ofs, len);
#endif
	return err;
}

/*
 * Helper function for jffs2_add_older_frag_to_fragtree().
 *
 * Checks the node if we are in the checking stage.
 */
static inline int check_node(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_tmp_dnode_info *tn)
{
	int ret;
	
	BUG_ON(ref_obsolete(tn->fn->raw));

	/* We only check the data CRC of unchecked nodes */
	if (ref_flags(tn->fn->raw) != REF_UNCHECKED)
		return 0;
	
	JFFS2_DBG_FRAGTREE2("check node %#04x-%#04x, phys offs %#08x.\n",
		tn->fn->ofs, tn->fn->ofs + tn->fn->size, ref_offset(tn->fn->raw));

	ret = check_node_data(c, tn);
	if (unlikely(ret < 0)) {
		JFFS2_ERROR("check_node_data() returned error: %d.\n",
			ret);
	} else if (unlikely(ret > 0)) {
		JFFS2_DBG_FRAGTREE2("CRC error, mark it obsolete.\n");
		jffs2_mark_node_obsolete(c, tn->fn->raw);
	}

	return ret;
}

/* 
 * Helper function for jffs2_add_older_frag_to_fragtree().
 *
 * Called when the new fragment that is being inserted
 * splits a hole fragment.
 */
static int split_hole(struct jffs2_sb_info *c, struct rb_root *root,
		      struct jffs2_node_frag *newfrag, struct jffs2_node_frag *hole)
{
	JFFS2_DBG_FRAGTREE2("fragment %#04x-%#04x splits the hole %#04x-%#04x\n",
		newfrag->ofs, newfrag->ofs + newfrag->size, hole->ofs, hole->ofs + hole->size);

	if (hole->ofs == newfrag->ofs) {
		/* 
		 * Well, the new fragment actually starts at the same offset as
		 * the hole.
		 */
		if (hole->ofs + hole->size > newfrag->ofs + newfrag->size) {
			/* 
			 * We replace the overlapped left part of the hole by
			 * the new node.
			 */
			
			JFFS2_DBG_FRAGTREE2("insert fragment %#04x-%#04x and cut the left part of the hole\n",
				newfrag->ofs, newfrag->ofs + newfrag->size);
			rb_replace_node(&hole->rb, &newfrag->rb, root);
			
			hole->ofs += newfrag->size;
			hole->size -= newfrag->size;
			
			/* 
			 * We know that 'hole' should be the right hand
			 * fragment.
			 */
			jffs2_fragtree_insert(hole, newfrag);
			rb_insert_color(&hole->rb, root);
		} else {
			/* 
			 * Ah, the new fragment is of the same size as the hole.
			 * Relace the hole by it.
			 */
			JFFS2_DBG_FRAGTREE2("insert fragment %#04x-%#04x and overwrite hole\n",
				newfrag->ofs, newfrag->ofs + newfrag->size);
			rb_replace_node(&hole->rb, &newfrag->rb, root);
			jffs2_free_node_frag(hole);
		}
	} else {
		/* The new fragment lefts some hole space at the left */
		
		struct jffs2_node_frag * newfrag2 = NULL;

		if (hole->ofs + hole->size > newfrag->ofs + newfrag->size) {
			/* The new frag also lefts some space at the right */
			newfrag2 = new_fragment(NULL, newfrag->ofs +
				newfrag->size, hole->ofs + hole->size
				- newfrag->ofs - newfrag->size);
			if (unlikely(!newfrag2)) {
				jffs2_free_node_frag(newfrag);
				return -ENOMEM;
			}
		}

		hole->size = newfrag->ofs - hole->ofs;
		JFFS2_DBG_FRAGTREE2("left the hole %#04x-%#04x at the left and inserd fragment %#04x-%#04x\n",
			hole->ofs, hole->ofs + hole->size, newfrag->ofs, newfrag->ofs + newfrag->size);

		jffs2_fragtree_insert(newfrag, hole);
		rb_insert_color(&newfrag->rb, root);
		
		if (newfrag2) {
			JFFS2_DBG_FRAGTREE2("left the hole %#04x-%#04x at the right\n",
				newfrag2->ofs, newfrag2->ofs + newfrag2->size);
			jffs2_fragtree_insert(newfrag2, newfrag);
			rb_insert_color(&newfrag2->rb, root);
		}
	}

	return 0;
}

/*
 * This function is used when we build inode. It expects the nodes are passed
 * in the decreasing version order. The whole point of this is to improve the
 * inodes checking on NAND: we check the nodes' data CRC only when they are not
 * obsoleted. Previously, add_frag_to_fragtree() function was used and
 * nodes were passed to it in the increasing version ordes and CRCs of all
 * nodes were checked.
 *
 * Note: tn->fn->size shouldn't be zero.
 *
 * Returns 0 if the node was inserted
 *         1 if it wasn't inserted (since it is obsolete)
 *         < 0 an if error occured
 */
int jffs2_add_older_frag_to_fragtree(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
				     struct jffs2_tmp_dnode_info *tn)
{
	struct jffs2_node_frag *this, *newfrag;
	uint32_t lastend;
	struct jffs2_full_dnode *fn = tn->fn;
	struct rb_root *root = &f->fragtree;
	uint32_t fn_size = fn->size, fn_ofs = fn->ofs;
	int err, checked = 0;
	int ref_flag;

	JFFS2_DBG_FRAGTREE("insert fragment %#04x-%#04x, ver %u\n", fn_ofs, fn_ofs + fn_size, tn->version);

	/* Skip all the nodes which are completed before this one starts */
	this = jffs2_lookup_node_frag(root, fn_ofs);
	if (this)
		JFFS2_DBG_FRAGTREE2("'this' found %#04x-%#04x (%s)\n", this->ofs, this->ofs + this->size, this->node ? "data" : "hole");

	if (this)
		lastend = this->ofs + this->size;
	else
		lastend = 0;
	
	/* Detect the preliminary type of node */
	if (fn->size >= PAGE_CACHE_SIZE)
		ref_flag = REF_PRISTINE;
	else
		ref_flag = REF_NORMAL;
	
	/* See if we ran off the end of the root */
	if (lastend <= fn_ofs) {
		/* We did */
		
		/* 
		 * We are going to insert the new node into the
		 * fragment tree, so check it.
		 */
		err = check_node(c, f, tn);
		if (err != 0)
			return err;

		fn->frags = 1;

		newfrag = new_fragment(fn, fn_ofs, fn_size);
		if (unlikely(!newfrag))
			return -ENOMEM;

		err = no_overlapping_node(c, root, newfrag, this, lastend);
		if (unlikely(err != 0)) {
			jffs2_free_node_frag(newfrag);
			return err;
		}

		goto out_ok;
	}

	fn->frags = 0;

	while (1) {
		/* 
		 * Here we have:
		 * fn_ofs < this->ofs + this->size && fn_ofs >= this->ofs.
		 * 
		 * Remember, 'this' has higher version, any non-hole node
		 * which is already in the fragtree is newer then the newly
		 * inserted.
		 */
		if (!this->node) {
			/* 
			 * 'this' is the hole fragment, so at least the
			 * beginning of the new fragment is valid.
			 */
			
			/* 
			 * We are going to insert the new node into the
			 * fragment tree, so check it.
			 */
			if (!checked) {
				err = check_node(c, f, tn);
				if (unlikely(err != 0))
					return err;
				checked = 1;
			}
			
			if (this->ofs + this->size >= fn_ofs + fn_size) {
				/* We split the hole on two parts */

				fn->frags += 1;
				newfrag = new_fragment(fn, fn_ofs, fn_size);
				if (unlikely(!newfrag))
					return -ENOMEM;

				err = split_hole(c, root, newfrag, this);
				if (unlikely(err))
					return err;
				goto out_ok;
			}

			/* 
			 * The beginning of the new fragment is valid since it
			 * overlaps the hole node.
			 */

			ref_flag = REF_NORMAL;

			fn->frags += 1;
			newfrag = new_fragment(fn, fn_ofs,
					this->ofs + this->size - fn_ofs);
			if (unlikely(!newfrag))
				return -ENOMEM;
			
			if (fn_ofs == this->ofs) {
				/* 
				 * The new node starts at the same offset as
				 * the hole and supersieds the hole.
				 */
				JFFS2_DBG_FRAGTREE2("add the new fragment instead of hole %#04x-%#04x, refcnt %d\n",
					fn_ofs, fn_ofs + this->ofs + this->size - fn_ofs, fn->frags);

				rb_replace_node(&this->rb, &newfrag->rb, root);
				jffs2_free_node_frag(this);
			} else {
				/* 
				 * The hole becomes shorter as its right part
				 * is supersieded by the new fragment.
				 */
				JFFS2_DBG_FRAGTREE2("reduce size of hole %#04x-%#04x to %#04x-%#04x\n",
					this->ofs, this->ofs + this->size, this->ofs, this->ofs + this->size - newfrag->size);
				
				JFFS2_DBG_FRAGTREE2("add new fragment %#04x-%#04x, refcnt %d\n", fn_ofs,
					fn_ofs + this->ofs + this->size - fn_ofs, fn->frags);
	
				this->size -= newfrag->size;
				jffs2_fragtree_insert(newfrag, this);
				rb_insert_color(&newfrag->rb, root);
			}
			
			fn_ofs += newfrag->size;
			fn_size -= newfrag->size;
			this = rb_entry(rb_next(&newfrag->rb),
					struct jffs2_node_frag, rb);

			JFFS2_DBG_FRAGTREE2("switch to the next 'this' fragment: %#04x-%#04x %s\n",
				this->ofs, this->ofs + this->size, this->node ? "(data)" : "(hole)");
		}

		/* 
		 * 'This' node is not the hole so it obsoletes the new fragment
		 * either fully or partially.
		 */
		if (this->ofs + this->size >= fn_ofs + fn_size) {
			/* The new node is obsolete, drop it */
			if (fn->frags == 0) {
				JFFS2_DBG_FRAGTREE2("%#04x-%#04x is obsolete, mark it obsolete\n", fn_ofs, fn_ofs + fn_size);
				ref_flag = REF_OBSOLETE;
			}
			goto out_ok;
		} else {
			struct jffs2_node_frag *new_this;
			
			/* 'This' node obsoletes the beginning of the new node */
			JFFS2_DBG_FRAGTREE2("the beginning %#04x-%#04x is obsolete\n", fn_ofs, this->ofs + this->size);

			ref_flag = REF_NORMAL;
			
			fn_size -= this->ofs + this->size - fn_ofs;
			fn_ofs = this->ofs + this->size;
			JFFS2_DBG_FRAGTREE2("now considering %#04x-%#04x\n", fn_ofs, fn_ofs + fn_size);
			
			new_this = rb_entry(rb_next(&this->rb), struct jffs2_node_frag, rb);
			if (!new_this) {
				/* 
				 * There is no next fragment. Add the rest of
				 * the new node as the right-hand child.
				 */
				if (!checked) {
					err = check_node(c, f, tn);
					if (unlikely(err != 0))
						return err;
					checked = 1;
				}
				
				fn->frags += 1;
				newfrag = new_fragment(fn, fn_ofs, fn_size);
				if (unlikely(!newfrag))
					return -ENOMEM;

				JFFS2_DBG_FRAGTREE2("there are no more fragments, insert %#04x-%#04x\n",
					newfrag->ofs, newfrag->ofs + newfrag->size);
				rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);			
				rb_insert_color(&newfrag->rb, root);
				goto out_ok;
			} else {
				this = new_this;
				JFFS2_DBG_FRAGTREE2("switch to the next 'this' fragment: %#04x-%#04x %s\n",
					this->ofs, this->ofs + this->size, this->node ? "(data)" : "(hole)");
			}
		}
	}

out_ok:
	BUG_ON(fn->size < PAGE_CACHE_SIZE && ref_flag == REF_PRISTINE);

	if (ref_flag == REF_OBSOLETE) {
		JFFS2_DBG_FRAGTREE2("the node is obsolete now\n");
		/* jffs2_mark_node_obsolete() will adjust space accounting */
		jffs2_mark_node_obsolete(c, fn->raw);
		return 1;
	}

	JFFS2_DBG_FRAGTREE2("the node is \"%s\" now\n", ref_flag == REF_NORMAL ? "REF_NORMAL" : "REF_PRISTINE");

	/* Space accounting was adjusted at check_node_data() */
	spin_lock(&c->erase_completion_lock);
	fn->raw->flash_offset = ref_offset(fn->raw) | ref_flag;
	spin_unlock(&c->erase_completion_lock);

	return 0;
}

void jffs2_set_inocache_state(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, int state)
{
	spin_lock(&c->inocache_lock);
	ic->state = state;
	wake_up(&c->inocache_wq);
	spin_unlock(&c->inocache_lock);
}

/* During mount, this needs no locking. During normal operation, its
   callers want to do other stuff while still holding the inocache_lock.
   Rather than introducing special case get_ino_cache functions or 
   callbacks, we just let the caller do the locking itself. */
   
struct jffs2_inode_cache *jffs2_get_ino_cache(struct jffs2_sb_info *c, uint32_t ino)
{
	struct jffs2_inode_cache *ret;

	ret = c->inocache_list[ino % INOCACHE_HASHSIZE];
	while (ret && ret->ino < ino) {
		ret = ret->next;
	}
	
	if (ret && ret->ino != ino)
		ret = NULL;

	return ret;
}

void jffs2_add_ino_cache (struct jffs2_sb_info *c, struct jffs2_inode_cache *new)
{
	struct jffs2_inode_cache **prev;

	spin_lock(&c->inocache_lock);
	if (!new->ino)
		new->ino = ++c->highest_ino;

	JFFS2_DBG_INOCACHE("add %p (ino #%u)\n", new, new->ino);

	prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];

	while ((*prev) && (*prev)->ino < new->ino) {
		prev = &(*prev)->next;
	}
	new->next = *prev;
	*prev = new;

	spin_unlock(&c->inocache_lock);
}

void jffs2_del_ino_cache(struct jffs2_sb_info *c, struct jffs2_inode_cache *old)
{
	struct jffs2_inode_cache **prev;

	JFFS2_DBG_INOCACHE("del %p (ino #%u)\n", old, old->ino);
	spin_lock(&c->inocache_lock);
	
	prev = &c->inocache_list[old->ino % INOCACHE_HASHSIZE];
	
	while ((*prev) && (*prev)->ino < old->ino) {
		prev = &(*prev)->next;
	}
	if ((*prev) == old) {
		*prev = old->next;
	}

	/* Free it now unless it's in READING or CLEARING state, which
	   are the transitions upon read_inode() and clear_inode(). The
	   rest of the time we know nobody else is looking at it, and 
	   if it's held by read_inode() or clear_inode() they'll free it
	   for themselves. */
	if (old->state != INO_STATE_READING && old->state != INO_STATE_CLEARING)
		jffs2_free_inode_cache(old);

	spin_unlock(&c->inocache_lock);
}

void jffs2_free_ino_caches(struct jffs2_sb_info *c)
{
	int i;
	struct jffs2_inode_cache *this, *next;
	
	for (i=0; i<INOCACHE_HASHSIZE; i++) {
		this = c->inocache_list[i];
		while (this) {
			next = this->next;
			jffs2_free_inode_cache(this);
			this = next;
		}
		c->inocache_list[i] = NULL;
	}
}

void jffs2_free_raw_node_refs(struct jffs2_sb_info *c)
{
	int i;
	struct jffs2_raw_node_ref *this, *next;

	for (i=0; i<c->nr_blocks; i++) {
		this = c->blocks[i].first_node;
		while(this) {
			next = this->next_phys;
			jffs2_free_raw_node_ref(this);
			this = next;
		}
		c->blocks[i].first_node = c->blocks[i].last_node = NULL;
	}
}
	
struct jffs2_node_frag *jffs2_lookup_node_frag(struct rb_root *fragtree, uint32_t offset)
{
	/* The common case in lookup is that there will be a node 
	   which precisely matches. So we go looking for that first */
	struct rb_node *next;
	struct jffs2_node_frag *prev = NULL;
	struct jffs2_node_frag *frag = NULL;

	JFFS2_DBG_FRAGTREE2("root %p, offset %d\n", fragtree, offset);

	next = fragtree->rb_node;

	while(next) {
		frag = rb_entry(next, struct jffs2_node_frag, rb);

		if (frag->ofs + frag->size <= offset) {
			/* Remember the closest smaller match on the way down */
			if (!prev || frag->ofs > prev->ofs)
				prev = frag;
			next = frag->rb.rb_right;
		} else if (frag->ofs > offset) {
			next = frag->rb.rb_left;
		} else {
			return frag;
		}
	}

	/* Exact match not found. Go back up looking at each parent,
	   and return the closest smaller one */

	if (prev)
		JFFS2_DBG_FRAGTREE2("no match. Returning frag %#04x-%#04x, closest previous\n",
			  prev->ofs, prev->ofs+prev->size);
	else 
		JFFS2_DBG_FRAGTREE2("returning NULL, empty fragtree\n");
	
	return prev;
}

/* Pass 'c' argument to indicate that nodes should be marked obsolete as
   they're killed. */
void jffs2_kill_fragtree(struct rb_root *root, struct jffs2_sb_info *c)
{
	struct jffs2_node_frag *frag;
	struct jffs2_node_frag *parent;

	if (!root->rb_node)
		return;

	JFFS2_DBG_FRAGTREE("killing\n");
	
	frag = (rb_entry(root->rb_node, struct jffs2_node_frag, rb));
	while(frag) {
		if (frag->rb.rb_left) {
			JFFS2_DBG_FRAGTREE2("going left from frag (%p) %#04x-%#04x\n",
				frag, frag->ofs, frag->ofs+frag->size);
			frag = frag_left(frag);
			continue;
		}
		if (frag->rb.rb_right) {
			JFFS2_DBG_FRAGTREE2("going right from frag (%p) %#04x-%#04x\n", 
				  frag, frag->ofs, frag->ofs+frag->size);
			frag = frag_right(frag);
			continue;
		}

		JFFS2_DBG_FRAGTREE2("frag %#04x-%#04x: node %p, frags %d\n",
			  frag->ofs, frag->ofs+frag->size, frag->node, frag->node?frag->node->frags:0);
			
		if (frag->node && !(--frag->node->frags)) {
			/* Not a hole, and it's the final remaining frag 
			   of this node. Free the node */
			if (c)
				jffs2_mark_node_obsolete(c, frag->node->raw);
			
			jffs2_free_full_dnode(frag->node);
		}
		parent = frag_parent(frag);
		if (parent) {
			if (frag_left(parent) == frag)
				parent->rb.rb_left = NULL;
			else 
				parent->rb.rb_right = NULL;
		}

		jffs2_free_node_frag(frag);
		frag = parent;

		cond_resched();
	}
}