aboutsummaryrefslogtreecommitdiff
path: root/fs/jffs2/readinode.c
blob: 389ea53ea487538061ff3b6da78e27df2f894ac1 (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
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

/*
 * Check the data CRC of the node.
 *
 * Returns: 0 if the data CRC is correct;
 * 	    1 - if incorrect;
 *	    error code if an error occurred.
 */
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, len;
	size_t retlen;

	BUG_ON(tn->csize == 0);

	/* Calculate how many bytes were already checked */
	ofs = ref_offset(ref) + sizeof(struct jffs2_raw_inode);
	len = tn->csize;

	if (jffs2_is_writebuffered(c)) {
		int adj = ofs % c->wbuf_pagesize;
		if (likely(adj))
			adj = c->wbuf_pagesize - adj;

		if (adj >= tn->csize) {
			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 += adj;
		len -= adj;
	}

	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. */
	err = mtd_point(c->mtd, ofs, len, &retlen, (void **)&buffer, NULL);
	if (!err && retlen < len) {
		JFFS2_WARNING("MTD point returned len too short: %zu instead of %u.\n", retlen, tn->csize);
		mtd_unpoint(c->mtd, ofs, retlen);
	} else if (err) {
		if (err != -EOPNOTSUPP)
			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: %zd 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
		mtd_unpoint(c->mtd, ofs, len);
#endif

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

adj_acc:
	jeb = &c->blocks[ref->flash_offset / c->sector_size];
	len = ref_totlen(c, jeb, ref);
	/* If it should be REF_NORMAL, it'll get marked as such when
	   we build the fragtree, shortly. No need to worry about GC
	   moving it while it's marked REF_PRISTINE -- GC won't happen
	   till we've finished checking every inode anyway. */
	ref->flash_offset |= REF_PRISTINE;
	/*
	 * 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;
	jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
	spin_unlock(&c->erase_completion_lock);

	return 0;

free_out:
	if(!pointed)
		kfree(buffer);
#ifndef __ECOS
	else
		mtd_unpoint(c->mtd, 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 int check_tn_node(struct jffs2_sb_info *c, 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;

	dbg_readinode("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)) {
		dbg_readinode("CRC error, mark it obsolete.\n");
		jffs2_mark_node_obsolete(c, tn->fn->raw);
	}

	return ret;
}

static struct jffs2_tmp_dnode_info *jffs2_lookup_tn(struct rb_root *tn_root, uint32_t offset)
{
	struct rb_node *next;
	struct jffs2_tmp_dnode_info *tn = NULL;

	dbg_readinode("root %p, offset %d\n", tn_root, offset);

	next = tn_root->rb_node;

	while (next) {
		tn = rb_entry(next, struct jffs2_tmp_dnode_info, rb);

		if (tn->fn->ofs < offset)
			next = tn->rb.rb_right;
		else if (tn->fn->ofs >= offset)
			next = tn->rb.rb_left;
		else
			break;
	}

	return tn;
}


static void jffs2_kill_tn(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
{
	jffs2_mark_node_obsolete(c, tn->fn->raw);
	jffs2_free_full_dnode(tn->fn);
	jffs2_free_tmp_dnode_info(tn);
}
/*
 * This function is used when we read an inode. Data nodes arrive in
 * arbitrary order -- they may be older or newer than the nodes which
 * are already in the tree. Where overlaps occur, the older node can
 * be discarded as long as the newer passes the CRC check. We don't
 * bother to keep track of holes in this rbtree, and neither do we deal
 * with frags -- we can have multiple entries starting at the same
 * offset, and the one with the smallest length will come first in the
 * ordering.
 *
 * Returns 0 if the node was handled (including marking it obsolete)
 *	 < 0 an if error occurred
 */
static int jffs2_add_tn_to_tree(struct jffs2_sb_info *c,
				struct jffs2_readinode_info *rii,
				struct jffs2_tmp_dnode_info *tn)
{
	uint32_t fn_end = tn->fn->ofs + tn->fn->size;
	struct jffs2_tmp_dnode_info *this, *ptn;

	dbg_readinode("insert fragment %#04x-%#04x, ver %u at %08x\n", tn->fn->ofs, fn_end, tn->version, ref_offset(tn->fn->raw));

	/* If a node has zero dsize, we only have to keep it if it might be the
	   node with highest version -- i.e. the one which will end up as f->metadata.
	   Note that such nodes won't be REF_UNCHECKED since there are no data to
	   check anyway. */
	if (!tn->fn->size) {
		if (rii->mdata_tn) {
			if (rii->mdata_tn->version < tn->version) {
				/* We had a candidate mdata node already */
				dbg_readinode("kill old mdata with ver %d\n", rii->mdata_tn->version);
				jffs2_kill_tn(c, rii->mdata_tn);
			} else {
				dbg_readinode("kill new mdata with ver %d (older than existing %d\n",
					      tn->version, rii->mdata_tn->version);
				jffs2_kill_tn(c, tn);
				return 0;
			}
		}
		rii->mdata_tn = tn;
		dbg_readinode("keep new mdata with ver %d\n", tn->version);
		return 0;
	}

	/* Find the earliest node which _may_ be relevant to this one */
	this = jffs2_lookup_tn(&rii->tn_root, tn->fn->ofs);
	if (this) {
		/* If the node is coincident with another at a lower address,
		   back up until the other node is found. It may be relevant */
		while (this->overlapped) {
			ptn = tn_prev(this);
			if (!ptn) {
				/*
				 * We killed a node which set the overlapped
				 * flags during the scan. Fix it up.
				 */
				this->overlapped = 0;
				break;
			}
			this = ptn;
		}
		dbg_readinode("'this' found %#04x-%#04x (%s)\n", this->fn->ofs, this->fn->ofs + this->fn->size, this->fn ? "data" : "hole");
	}

	while (this) {
		if (this->fn->ofs > fn_end)
			break;
		dbg_readinode("Ponder this ver %d, 0x%x-0x%x\n",
			      this->version, this->fn->ofs, this->fn->size);

		if (this->version == tn->version) {
			/* Version number collision means REF_PRISTINE GC. Accept either of them
			   as long as the CRC is correct. Check the one we have already...  */
			if (!check_tn_node(c, this)) {
				/* The one we already had was OK. Keep it and throw away the new one */
				dbg_readinode("Like old node. Throw away new\n");
				jffs2_kill_tn(c, tn);
				return 0;
			} else {
				/* Who cares if the new one is good; keep it for now anyway. */
				dbg_readinode("Like new node. Throw away old\n");
				rb_replace_node(&this->rb, &tn->rb, &rii->tn_root);
				jffs2_kill_tn(c, this);
				/* Same overlapping from in front and behind */
				return 0;
			}
		}
		if (this->version < tn->version &&
		    this->fn->ofs >= tn->fn->ofs &&
		    this->fn->ofs + this->fn->size <= fn_end) {
			/* New node entirely overlaps 'this' */
			if (check_tn_node(c, tn)) {
				dbg_readinode("new node bad CRC\n");
				jffs2_kill_tn(c, tn);
				return 0;
			}
			/* ... and is good. Kill 'this' and any subsequent nodes which are also overlapped */
			while (this && this->fn->ofs + this->fn->size <= fn_end) {
				struct jffs2_tmp_dnode_info *next = tn_next(this);
				if (this->version < tn->version) {
					tn_erase(this, &rii->tn_root);
					dbg_readinode("Kill overlapped ver %d, 0x%x-0x%x\n",
						      this->version, this->fn->ofs,
						      this->fn->ofs+this->fn->size);
					jffs2_kill_tn(c, this);
				}
				this = next;
			}
			dbg_readinode("Done killing overlapped nodes\n");
			continue;
		}
		if (this->version > tn->version &&
		    this->fn->ofs <= tn->fn->ofs &&
		    this->fn->ofs+this->fn->size >= fn_end) {
			/* New node entirely overlapped by 'this' */
			if (!check_tn_node(c, this)) {
				dbg_readinode("Good CRC on old node. Kill new\n");
				jffs2_kill_tn(c, tn);
				return 0;
			}
			/* ... but 'this' was bad. Replace it... */
			dbg_readinode("Bad CRC on old overlapping node. Kill it\n");
			tn_erase(this, &rii->tn_root);
			jffs2_kill_tn(c, this);
			break;
		}

		this = tn_next(this);
	}

	/* We neither completely obsoleted nor were completely
	   obsoleted by an earlier node. Insert into the tree */
	{
		struct rb_node *parent;
		struct rb_node **link = &rii->tn_root.rb_node;
		struct jffs2_tmp_dnode_info *insert_point = NULL;

		while (*link) {
			parent = *link;
			insert_point = rb_entry(parent, struct jffs2_tmp_dnode_info, rb);
			if (tn->fn->ofs > insert_point->fn->ofs)
				link = &insert_point->rb.rb_right;
			else if (tn->fn->ofs < insert_point->fn->ofs ||
				 tn->fn->size < insert_point->fn->size)
				link = &insert_point->rb.rb_left;
			else
				link = &insert_point->rb.rb_right;
		}
		rb_link_node(&tn->rb, &insert_point->rb, link);
		rb_insert_color(&tn->rb, &rii->tn_root);
	}

	/* If there's anything behind that overlaps us, note it */
	this = tn_prev(tn);
	if (this) {
		while (1) {
			if (this->fn->ofs + this->fn->size > tn->fn->ofs) {
				dbg_readinode("Node is overlapped by %p (v %d, 0x%x-0x%x)\n",
					      this, this->version, this->fn->ofs,
					      this->fn->ofs+this->fn->size);
				tn->overlapped = 1;
				break;
			}
			if (!this->overlapped)
				break;

			ptn = tn_prev(this);
			if (!ptn) {
				/*
				 * We killed a node which set the overlapped
				 * flags during the scan. Fix it up.
				 */
				this->overlapped = 0;
				break;
			}
			this = ptn;
		}
	}

	/* If the new node overlaps anything ahead, note it */
	this = tn_next(tn);
	while (this && this->fn->ofs < fn_end) {
		this->overlapped = 1;
		dbg_readinode("Node ver %d, 0x%x-0x%x is overlapped\n",
			      this->version, this->fn->ofs,
			      this->fn->ofs+this->fn->size);
		this = tn_next(this);
	}
	return 0;
}

/* Trivial function to remove the last node in the tree. Which by definition
   has no right-hand child — so can be removed just by making its left-hand
   child (if any) take its place under its parent. Since this is only done
   when we're consuming the whole tree, there's no need to use rb_erase()
   and let it worry about adjusting colours and balancing the tree. That
   would just be a waste of time. */
static void eat_last(struct rb_root *root, struct rb_node *node)
{
	struct rb_node *parent = rb_parent(node);
	struct rb_node **link;

	/* LAST! */
	BUG_ON(node->rb_right);

	if (!parent)
		link = &root->rb_node;
	else if (node == parent->rb_left)
		link = &parent->rb_left;
	else
		link = &parent->rb_right;

	*link = node->rb_left;
	if (node->rb_left)
		node->rb_left->__rb_parent_color = node->__rb_parent_color;
}

/* We put the version tree in reverse order, so we can use the same eat_last()
   function that we use to consume the tmpnode tree (tn_root). */
static void ver_insert(struct rb_root *ver_root, struct jffs2_tmp_dnode_info *tn)
{
	struct rb_node **link = &ver_root->rb_node;
	struct rb_node *parent = NULL;
	struct jffs2_tmp_dnode_info *this_tn;

	while (*link) {
		parent = *link;
		this_tn = rb_entry(parent, struct jffs2_tmp_dnode_info, rb);

		if (tn->version > this_tn->version)
			link = &parent->rb_left;
		else
			link = &parent->rb_right;
	}
	dbg_readinode("Link new node at %p (root is %p)\n", link, ver_root);
	rb_link_node(&tn->rb, parent, link);
	rb_insert_color(&tn->rb, ver_root);
}

/* Build final, normal fragtree from tn tree. It doesn't matter which order
   we add nodes to the real fragtree, as long as they don't overlap. And
   having thrown away the majority of overlapped nodes as we went, there
   really shouldn't be many sets of nodes which do overlap. If we start at
   the end, we can use the overlap markers -- we can just eat nodes which
   aren't overlapped, and when we encounter nodes which _do_ overlap we
   sort them all into a temporary tree in version order before replaying them. */
static int jffs2_build_inode_fragtree(struct jffs2_sb_info *c,
				      struct jffs2_inode_info *f,
				      struct jffs2_readinode_info *rii)
{
	struct jffs2_tmp_dnode_info *pen, *last, *this;
	struct rb_root ver_root = RB_ROOT;
	uint32_t high_ver = 0;

	if (rii->mdata_tn) {
		dbg_readinode("potential mdata is ver %d at %p\n", rii->mdata_tn->version, rii->mdata_tn);
		high_ver = rii->mdata_tn->version;
		rii->latest_ref = rii->mdata_tn->fn->raw;
	}
#ifdef JFFS2_DBG_READINODE_MESSAGES
	this = tn_last(&rii->tn_root);
	while (this) {
		dbg_readinode("tn %p ver %d range 0x%x-0x%x ov %d\n", this, this->version, this->fn->ofs,
			      this->fn->ofs+this->fn->size, this->overlapped);
		this = tn_prev(this);
	}
#endif
	pen = tn_last(&rii->tn_root);
	while ((last = pen)) {
		pen = tn_prev(last);

		eat_last(&rii->tn_root, &last->rb);
		ver_insert(&ver_root, last);

		if (unlikely(last->overlapped)) {
			if (pen)
				continue;
			/*
			 * We killed a node which set the overlapped
			 * flags during the scan. Fix it up.
			 */
			last->overlapped = 0;
		}

		/* Now we have a bunch of nodes in reverse version
		   order, in the tree at ver_root. Most of the time,
		   there'll actually be only one node in the 'tree',
		   in fact. */
		this = tn_last(&ver_root);

		while (this) {
			struct jffs2_tmp_dnode_info *vers_next;
			int ret;
			vers_next = tn_prev(this);
			eat_last(&ver_root, &this->rb);
			if (check_tn_node(c, this)) {
				dbg_readinode("node ver %d, 0x%x-0x%x failed CRC\n",
					     this->version, this->fn->ofs,
					     this->fn->ofs+this->fn->size);
				jffs2_kill_tn(c, this);
			} else {
				if (this->version > high_ver) {
					/* Note that this is different from the other
					   highest_version, because this one is only
					   counting _valid_ nodes which could give the
					   latest inode metadata */
					high_ver = this->version;
					rii->latest_ref = this->fn->raw;
				}
				dbg_readinode("Add %p (v %d, 0x%x-0x%x, ov %d) to fragtree\n",
					     this, this->version, this->fn->ofs,
					     this->fn->ofs+this->fn->size, this->overlapped);

				ret = jffs2_add_full_dnode_to_inode(c, f, this->fn);
				if (ret) {
					/* Free the nodes in vers_root; let the caller
					   deal with the rest */
					JFFS2_ERROR("Add node to tree failed %d\n", ret);
					while (1) {
						vers_next = tn_prev(this);
						if (check_tn_node(c, this))
							jffs2_mark_node_obsolete(c, this->fn->raw);
						jffs2_free_full_dnode(this->fn);
						jffs2_free_tmp_dnode_info(this);
						this = vers_next;
						if (!this)
							break;
						eat_last(&ver_root, &vers_next->rb);
					}
					return ret;
				}
				jffs2_free_tmp_dnode_info(this);
			}
			this = vers_next;
		}
	}
	return 0;
}

static void jffs2_free_tmp_dnode_info_list(struct rb_root *list)
{
	struct jffs2_tmp_dnode_info *tn, *next;

	rbtree_postorder_for_each_entry_safe(tn, next, list, rb) {
			jffs2_free_full_dnode(tn->fn);
			jffs2_free_tmp_dnode_info(tn);
	}

	*list = RB_ROOT;
}

static void jffs2_free_full_dirent_list(struct jffs2_full_dirent *fd)
{
	struct jffs2_full_dirent *next;

	while (fd) {
		next = fd->next;
		jffs2_free_full_dirent(fd);
		fd = next;
	}
}

/* Returns first valid node after 'ref'. May return 'ref' */
static struct jffs2_raw_node_ref *jffs2_first_valid_node(struct jffs2_raw_node_ref *ref)
{
	while (ref && ref->next_in_ino) {
		if (!ref_obsolete(ref))
			return ref;
		dbg_noderef("node at 0x%08x is obsoleted. Ignoring.\n", ref_offset(ref));
		ref = ref->next_in_ino;
	}
	return NULL;
}

/*
 * Helper function for jffs2_get_inode_nodes().
 * It is called every time an directory entry node is found.
 *
 * Returns: 0 on success;
 * 	    negative error code on failure.
 */
static inline int read_direntry(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
				struct jffs2_raw_dirent *rd, size_t read,
				struct jffs2_readinode_info *rii)
{
	struct jffs2_full_dirent *fd;
	uint32_t crc;

	/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
	BUG_ON(ref_obsolete(ref));

	crc = crc32(0, rd, sizeof(*rd) - 8);
	if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
		JFFS2_NOTICE("header CRC failed on dirent node at %#08x: read %#08x, calculated %#08x\n",
			     ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
		jffs2_mark_node_obsolete(c, ref);
		return 0;
	}

	/* If we've never checked the CRCs on this node, check them now */
	if (ref_flags(ref) == REF_UNCHECKED) {
		struct jffs2_eraseblock *jeb;
		int len;

		/* Sanity check */
		if (unlikely(PAD((rd->nsize + sizeof(*rd))) != PAD(je32_to_cpu(rd->totlen)))) {
			JFFS2_ERROR("illegal nsize in node at %#08x: nsize %#02x, totlen %#04x\n",
				    ref_offset(ref), rd->nsize, je32_to_cpu(rd->totlen));
			jffs2_mark_node_obsolete(c, ref);
			return 0;
		}

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

		spin_lock(&c->erase_completion_lock);
		jeb->used_size += len;
		jeb->unchecked_size -= len;
		c->used_size += len;
		c->unchecked_size -= len;
		ref->flash_offset = ref_offset(ref) | dirent_node_state(rd);
		spin_unlock(&c->erase_completion_lock);
	}

	fd = jffs2_alloc_full_dirent(rd->nsize + 1);
	if (unlikely(!fd))
		return -ENOMEM;

	fd->raw = ref;
	fd->version = je32_to_cpu(rd->version);
	fd->ino = je32_to_cpu(rd->ino);
	fd->type = rd->type;

	if (fd->version > rii->highest_version)
		rii->highest_version = fd->version;

	/* Pick out the mctime of the latest dirent */
	if(fd->version > rii->mctime_ver && je32_to_cpu(rd->mctime)) {
		rii->mctime_ver = fd->version;
		rii->latest_mctime = je32_to_cpu(rd->mctime);
	}

	/*
	 * Copy as much of the name as possible from the raw
	 * dirent we've already read from the flash.
	 */
	if (read > sizeof(*rd))
		memcpy(&fd->name[0], &rd->name[0],
		       min_t(uint32_t, rd->nsize, (read - sizeof(*rd)) ));

	/* Do we need to copy any more of the name directly from the flash? */
	if (rd->nsize + sizeof(*rd) > read) {
		/* FIXME: point() */
		int err;
		int already = read - sizeof(*rd);

		err = jffs2_flash_read(c, (ref_offset(ref)) + read,
				rd->nsize - already, &read, &fd->name[already]);
		if (unlikely(read != rd->nsize - already) && likely(!err)) {
			jffs2_free_full_dirent(fd);
			JFFS2_ERROR("short read: wanted %d bytes, got %zd\n",
				    rd->nsize - already, read);
			return -EIO;
		}

		if (unlikely(err)) {
			JFFS2_ERROR("read remainder of name: error %d\n", err);
			jffs2_free_full_dirent(fd);
			return -EIO;
		}
	}

	fd->nhash = full_name_hash(NULL, fd->name, rd->nsize);
	fd->next = NULL;
	fd->name[rd->nsize] = '\0';

	/*
	 * Wheee. We now have a complete jffs2_full_dirent structure, with
	 * the name in it and everything. Link it into the list
	 */
	jffs2_add_fd_to_list(c, fd, &rii->fds);

	return 0;
}

/*
 * Helper function for jffs2_get_inode_nodes().
 * It is called every time an inode node is found.
 *
 * Returns: 0 on success (possibly after marking a bad node obsolete);
 * 	    negative error code on failure.
 */
static inline int read_dnode(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
			     struct jffs2_raw_inode *rd, int rdlen,
			     struct jffs2_readinode_info *rii)
{
	struct jffs2_tmp_dnode_info *tn;
	uint32_t len, csize;
	int ret = 0;
	uint32_t crc;

	/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
	BUG_ON(ref_obsolete(ref));

	crc = crc32(0, rd, sizeof(*rd) - 8);
	if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
		JFFS2_NOTICE("node CRC failed on dnode at %#08x: read %#08x, calculated %#08x\n",
			     ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
		jffs2_mark_node_obsolete(c, ref);
		return 0;
	}

	tn = jffs2_alloc_tmp_dnode_info();
	if (!tn) {
		JFFS2_ERROR("failed to allocate tn (%zu bytes).\n", sizeof(*tn));
		return -ENOMEM;
	}

	tn->partial_crc = 0;
	csize = je32_to_cpu(rd->csize);

	/* If we've never checked the CRCs on this node, check them now */
	if (ref_flags(ref) == REF_UNCHECKED) {

		/* Sanity checks */
		if (unlikely(je32_to_cpu(rd->offset) > je32_to_cpu(rd->isize)) ||
		    unlikely(PAD(je32_to_cpu(rd->csize) + sizeof(*rd)) != PAD(je32_to_cpu(rd->totlen)))) {
			JFFS2_WARNING("inode node header CRC is corrupted at %#08x\n", ref_offset(ref));
			jffs2_dbg_dump_node(c, ref_offset(ref));
			jffs2_mark_node_obsolete(c, ref);
			goto free_out;
		}

		if (jffs2_is_writebuffered(c) && csize != 0) {
			/* At this point we are supposed to check the data CRC
			 * of our unchecked node. But thus far, we do not
			 * know whether the node is valid or obsolete. To
			 * figure this out, we need to walk all the nodes of
			 * the inode and build the inode fragtree. We don't
			 * want to spend time checking data of nodes which may
			 * later be found to be obsolete. So we put off the full
			 * data CRC checking until we have read all the inode
			 * nodes and have started building the fragtree.
			 *
			 * The fragtree is being built starting with nodes
			 * having the highest version number, so we'll be able
			 * to detect whether a node is valid (i.e., it is not
			 * overlapped by a node with higher version) or not.
			 * And we'll be able to check only those nodes, which
			 * are not obsolete.
			 *
			 * Of course, this optimization only makes sense in case
			 * of NAND flashes (or other flashes with
			 * !jffs2_can_mark_obsolete()), since on NOR flashes
			 * nodes are marked obsolete physically.
			 *
			 * Since NAND flashes (or other flashes with
			 * jffs2_is_writebuffered(c)) are anyway read by
			 * fractions of c->wbuf_pagesize, and we have just read
			 * the node header, it is likely that the starting part
			 * of the node data is also read when we read the
			 * header. So we don't mind to check the CRC of the
			 * starting part of the data of the node now, and check
			 * the second part later (in jffs2_check_node_data()).
			 * Of course, we will not need to re-read and re-check
			 * the NAND page which we have just read. This is why we
			 * read the whole NAND page at jffs2_get_inode_nodes(),
			 * while we needed only the node header.
			 */
			unsigned char *buf;

			/* 'buf' will point to the start of data */
			buf = (unsigned char *)rd + sizeof(*rd);
			/* len will be the read data length */
			len = min_t(uint32_t, rdlen - sizeof(*rd), csize);
			tn->partial_crc = crc32(0, buf, len);

			dbg_readinode("Calculates CRC (%#08x) for %d bytes, csize %d\n", tn->partial_crc, len, csize);

			/* If we actually calculated the whole data CRC
			 * and it is wrong, drop the node. */
			if (len >= csize && unlikely(tn->partial_crc != je32_to_cpu(rd->data_crc))) {
				JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
					ref_offset(ref), tn->partial_crc, je32_to_cpu(rd->data_crc));
				jffs2_mark_node_obsolete(c, ref);
				goto free_out;
			}

		} else if (csize == 0) {
			/*
			 * We checked the header CRC. If the node has no data, adjust
			 * the space accounting now. For other nodes this will be done
			 * later either when the node is marked obsolete or when its
			 * data is checked.
			 */
			struct jffs2_eraseblock *jeb;

			dbg_readinode("the node has no data.\n");
			jeb = &c->blocks[ref->flash_offset / c->sector_size];
			len = ref_totlen(c, jeb, ref);

			spin_lock(&c->erase_completion_lock);
			jeb->used_size += len;
			jeb->unchecked_size -= len;
			c->used_size += len;
			c->unchecked_size -= len;
			ref->flash_offset = ref_offset(ref) | REF_NORMAL;
			spin_unlock(&c->erase_completion_lock);
		}
	}

	tn->fn = jffs2_alloc_full_dnode();
	if (!tn->fn) {
		JFFS2_ERROR("alloc fn failed\n");
		ret = -ENOMEM;
		goto free_out;
	}

	tn->version = je32_to_cpu(rd->version);
	tn->fn->ofs = je32_to_cpu(rd->offset);
	tn->data_crc = je32_to_cpu(rd->data_crc);
	tn->csize = csize;
	tn->fn->raw = ref;
	tn->overlapped = 0;

	if (tn->version > rii->highest_version)
		rii->highest_version = tn->version;

	/* There was a bug where we wrote hole nodes out with
	   csize/dsize swapped. Deal with it */
	if (rd->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(rd->dsize) && csize)
		tn->fn->size = csize;
	else // normal case...
		tn->fn->size = je32_to_cpu(rd->dsize);

	dbg_readinode2("dnode @%08x: ver %u, offset %#04x, dsize %#04x, csize %#04x\n",
		       ref_offset(ref), je32_to_cpu(rd->version),
		       je32_to_cpu(rd->offset), je32_to_cpu(rd->dsize), csize);

	ret = jffs2_add_tn_to_tree(c, rii, tn);

	if (ret) {
		jffs2_free_full_dnode(tn->fn);
	free_out:
		jffs2_free_tmp_dnode_info(tn);
		return ret;
	}
#ifdef JFFS2_DBG_READINODE2_MESSAGES
	dbg_readinode2("After adding ver %d:\n", je32_to_cpu(rd->version));
	tn = tn_first(&rii->tn_root);
	while (tn) {
		dbg_readinode2("%p: v %d r 0x%x-0x%x ov %d\n",
			       tn, tn->version, tn->fn->ofs,
			       tn->fn->ofs+tn->fn->size, tn->overlapped);
		tn = tn_next(tn);
	}
#endif
	return 0;
}

/*
 * Helper function for jffs2_get_inode_nodes().
 * It is called every time an unknown node is found.
 *
 * Returns: 0 on success;
 * 	    negative error code on failure.
 */
static inline int read_unknown(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref, struct jffs2_unknown_node *un)
{
	/* We don't mark unknown nodes as REF_UNCHECKED */
	if (ref_flags(ref) == REF_UNCHECKED) {
		JFFS2_ERROR("REF_UNCHECKED but unknown node at %#08x\n",
			    ref_offset(ref));
		JFFS2_ERROR("Node is {%04x,%04x,%08x,%08x}. Please report this error.\n",
			    je16_to_cpu(un->magic), je16_to_cpu(un->nodetype),
			    je32_to_cpu(un->totlen), je32_to_cpu(un->hdr_crc));
		jffs2_mark_node_obsolete(c, ref);
		return 0;
	}

	un->nodetype = cpu_to_je16(JFFS2_NODE_ACCURATE | je16_to_cpu(un->nodetype));

	switch(je16_to_cpu(un->nodetype) & JFFS2_COMPAT_MASK) {

	case JFFS2_FEATURE_INCOMPAT:
		JFFS2_ERROR("unknown INCOMPAT nodetype %#04X at %#08x\n",
			    je16_to_cpu(un->nodetype), ref_offset(ref));
		/* EEP */
		BUG();
		break;

	case JFFS2_FEATURE_ROCOMPAT:
		JFFS2_ERROR("unknown ROCOMPAT nodetype %#04X at %#08x\n",
			    je16_to_cpu(un->nodetype), ref_offset(ref));
		BUG_ON(!(c->flags & JFFS2_SB_FLAG_RO));
		break;

	case JFFS2_FEATURE_RWCOMPAT_COPY:
		JFFS2_NOTICE("unknown RWCOMPAT_COPY nodetype %#04X at %#08x\n",
			     je16_to_cpu(un->nodetype), ref_offset(ref));
		break;

	case JFFS2_FEATURE_RWCOMPAT_DELETE:
		JFFS2_NOTICE("unknown RWCOMPAT_DELETE nodetype %#04X at %#08x\n",
			     je16_to_cpu(un->nodetype), ref_offset(ref));
		jffs2_mark_node_obsolete(c, ref);
		return 0;
	}

	return 0;
}

/*
 * Helper function for jffs2_get_inode_nodes().
 * The function detects whether more data should be read and reads it if yes.
 *
 * Returns: 0 on success;
 * 	    negative error code on failure.
 */
static int read_more(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
		     int needed_len, int *rdlen, unsigned char *buf)
{
	int err, to_read = needed_len - *rdlen;
	size_t retlen;
	uint32_t offs;

	if (jffs2_is_writebuffered(c)) {
		int rem = to_read % c->wbuf_pagesize;

		if (rem)
			to_read += c->wbuf_pagesize - rem;
	}

	/* We need to read more data */
	offs = ref_offset(ref) + *rdlen;

	dbg_readinode("read more %d bytes\n", to_read);

	err = jffs2_flash_read(c, offs, to_read, &retlen, buf + *rdlen);
	if (err) {
		JFFS2_ERROR("can not read %d bytes from 0x%08x, "
			"error code: %d.\n", to_read, offs, err);
		return err;
	}

	if (retlen < to_read) {
		JFFS2_ERROR("short read at %#08x: %zu instead of %d.\n",
				offs, retlen, to_read);
		return -EIO;
	}

	*rdlen += to_read;
	return 0;
}

/* Get tmp_dnode_info and full_dirent for all non-obsolete nodes associated
   with this ino. Perform a preliminary ordering on data nodes, throwing away
   those which are completely obsoleted by newer ones. The naïve approach we
   use to take of just returning them _all_ in version order will cause us to
   run out of memory in certain degenerate cases. */
static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
				 struct jffs2_readinode_info *rii)
{
	struct jffs2_raw_node_ref *ref, *valid_ref;
	unsigned char *buf = NULL;
	union jffs2_node_union *node;
	size_t retlen;
	int len, err;

	rii->mctime_ver = 0;

	dbg_readinode("ino #%u\n", f->inocache->ino);

	/* FIXME: in case of NOR and available ->point() this
	 * needs to be fixed. */
	len = sizeof(union jffs2_node_union) + c->wbuf_pagesize;
	buf = kmalloc(len, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	spin_lock(&c->erase_completion_lock);
	valid_ref = jffs2_first_valid_node(f->inocache->nodes);
	if (!valid_ref && f->inocache->ino != 1)
		JFFS2_WARNING("Eep. No valid nodes for ino #%u.\n", f->inocache->ino);
	while (valid_ref) {
		/* We can hold a pointer to a non-obsolete node without the spinlock,
		   but _obsolete_ nodes may disappear at any time, if the block
		   they're in gets erased. So if we mark 'ref' obsolete while we're
		   not holding the lock, it can go away immediately. For that reason,
		   we find the next valid node first, before processing 'ref'.
		*/
		ref = valid_ref;
		valid_ref = jffs2_first_valid_node(ref->next_in_ino);
		spin_unlock(&c->erase_completion_lock);

		cond_resched();

		/*
		 * At this point we don't know the type of the node we're going
		 * to read, so we do not know the size of its header. In order
		 * to minimize the amount of flash IO we assume the header is
		 * of size = JFFS2_MIN_NODE_HEADER.
		 */
		len = JFFS2_MIN_NODE_HEADER;
		if (jffs2_is_writebuffered(c)) {
			int end, rem;

			/*
			 * We are about to read JFFS2_MIN_NODE_HEADER bytes,
			 * but this flash has some minimal I/O unit. It is
			 * possible that we'll need to read more soon, so read
			 * up to the next min. I/O unit, in order not to
			 * re-read the same min. I/O unit twice.
			 */
			end = ref_offset(ref) + len;
			rem = end % c->wbuf_pagesize;
			if (rem)
				end += c->wbuf_pagesize - rem;
			len = end - ref_offset(ref);
		}

		dbg_readinode("read %d bytes at %#08x(%d).\n", len, ref_offset(ref), ref_flags(ref));

		/* FIXME: point() */
		err = jffs2_flash_read(c, ref_offset(ref), len, &retlen, buf);
		if (err) {
			JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ref_offset(ref), err);
			goto free_out;
		}

		if (retlen < len) {
			JFFS2_ERROR("short read at %#08x: %zu instead of %d.\n", ref_offset(ref), retlen, len);
			err = -EIO;
			goto free_out;
		}

		node = (union jffs2_node_union *)buf;

		/* No need to mask in the valid bit; it shouldn't be invalid */
		if (je32_to_cpu(node->u.hdr_crc) != crc32(0, node, sizeof(node->u)-4)) {
			JFFS2_NOTICE("Node header CRC failed at %#08x. {%04x,%04x,%08x,%08x}\n",
				     ref_offset(ref), je16_to_cpu(node->u.magic),
				     je16_to_cpu(node->u.nodetype),
				     je32_to_cpu(node->u.totlen),
				     je32_to_cpu(node->u.hdr_crc));
			jffs2_dbg_dump_node(c, ref_offset(ref));
			jffs2_mark_node_obsolete(c, ref);
			goto cont;
		}
		if (je16_to_cpu(node->u.magic) != JFFS2_MAGIC_BITMASK) {
			/* Not a JFFS2 node, whinge and move on */
			JFFS2_NOTICE("Wrong magic bitmask 0x%04x in node header at %#08x.\n",
				     je16_to_cpu(node->u.magic), ref_offset(ref));
			jffs2_mark_node_obsolete(c, ref);
			goto cont;
		}

		switch (je16_to_cpu(node->u.nodetype)) {

		case JFFS2_NODETYPE_DIRENT:

			if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_dirent) &&
			    len < sizeof(struct jffs2_raw_dirent)) {
				err = read_more(c, ref, sizeof(struct jffs2_raw_dirent), &len, buf);
				if (unlikely(err))
					goto free_out;
			}

			err = read_direntry(c, ref, &node->d, retlen, rii);
			if (unlikely(err))
				goto free_out;

			break;

		case JFFS2_NODETYPE_INODE:

			if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_inode) &&
			    len < sizeof(struct jffs2_raw_inode)) {
				err = read_more(c, ref, sizeof(struct jffs2_raw_inode), &len, buf);
				if (unlikely(err))
					goto free_out;
			}

			err = read_dnode(c, ref, &node->i, len, rii);
			if (unlikely(err))
				goto free_out;

			break;

		default:
			if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_unknown_node) &&
			    len < sizeof(struct jffs2_unknown_node)) {
				err = read_more(c, ref, sizeof(struct jffs2_unknown_node), &len, buf);
				if (unlikely(err))
					goto free_out;
			}

			err = read_unknown(c, ref, &node->u);
			if (unlikely(err))
				goto free_out;

		}
	cont:
		spin_lock(&c->erase_completion_lock);
	}

	spin_unlock(&c->erase_completion_lock);
	kfree(buf);

	f->highest_version = rii->highest_version;

	dbg_readinode("nodes of inode #%u were read, the highest version is %u, latest_mctime %u, mctime_ver %u.\n",
		      f->inocache->ino, rii->highest_version, rii->latest_mctime,
		      rii->mctime_ver);
	return 0;

 free_out:
	jffs2_free_tmp_dnode_info_list(&rii->tn_root);
	jffs2_free_full_dirent_list(rii->fds);
	rii->fds = NULL;
	kfree(buf);
	return err;
}

static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
					struct jffs2_inode_info *f,
					struct jffs2_raw_inode *latest_node)
{
	struct jffs2_readinode_info rii;
	uint32_t crc, new_size;
	size_t retlen;
	int ret;

	dbg_readinode("ino #%u pino/nlink is %d\n", f->inocache->ino,
		      f->inocache->pino_nlink);

	memset(&rii, 0, sizeof(rii));

	/* Grab all nodes relevant to this ino */
	ret = jffs2_get_inode_nodes(c, f, &rii);

	if (ret) {
		JFFS2_ERROR("cannot read nodes for ino %u, returned error is %d\n", f->inocache->ino, ret);
		if (f->inocache->state == INO_STATE_READING)
			jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
		return ret;
	}

	ret = jffs2_build_inode_fragtree(c, f, &rii);
	if (ret) {
		JFFS2_ERROR("Failed to build final fragtree for inode #%u: error %d\n",
			    f->inocache->ino, ret);
		if (f->inocache->state == INO_STATE_READING)
			jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
		jffs2_free_tmp_dnode_info_list(&rii.tn_root);
		/* FIXME: We could at least crc-check them all */
		if (rii.mdata_tn) {
			jffs2_free_full_dnode(rii.mdata_tn->fn);
			jffs2_free_tmp_dnode_info(rii.mdata_tn);
			rii.mdata_tn = NULL;
		}
		return ret;
	}

	if (rii.mdata_tn) {
		if (rii.mdata_tn->fn->raw == rii.latest_ref) {
			f->metadata = rii.mdata_tn->fn;
			jffs2_free_tmp_dnode_info(rii.mdata_tn);
		} else {
			jffs2_kill_tn(c, rii.mdata_tn);
		}
		rii.mdata_tn = NULL;
	}

	f->dents = rii.fds;

	jffs2_dbg_fragtree_paranoia_check_nolock(f);

	if (unlikely(!rii.latest_ref)) {
		/* No data nodes for this inode. */
		if (f->inocache->ino != 1) {
			JFFS2_WARNING("no data nodes found for ino #%u\n", f->inocache->ino);
			if (!rii.fds) {
				if (f->inocache->state == INO_STATE_READING)
					jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
				return -EIO;
			}
			JFFS2_NOTICE("but it has children so we fake some modes for it\n");
		}
		latest_node->mode = cpu_to_jemode(S_IFDIR|S_IRUGO|S_IWUSR|S_IXUGO);
		latest_node->version = cpu_to_je32(0);
		latest_node->atime = latest_node->ctime = latest_node->mtime = cpu_to_je32(0);
		latest_node->isize = cpu_to_je32(0);
		latest_node->gid = cpu_to_je16(0);
		latest_node->uid = cpu_to_je16(0);
		if (f->inocache->state == INO_STATE_READING)
			jffs2_set_inocache_state(c, f->inocache, INO_STATE_PRESENT);
		return 0;
	}

	ret = jffs2_flash_read(c, ref_offset(rii.latest_ref), sizeof(*latest_node), &retlen, (void *)latest_node);
	if (ret || retlen != sizeof(*latest_node)) {
		JFFS2_ERROR("failed to read from flash: error %d, %zd of %zd bytes read\n",
			ret, retlen, sizeof(*latest_node));
		/* FIXME: If this fails, there seems to be a memory leak. Find it. */
		return ret ? ret : -EIO;
	}

	crc = crc32(0, latest_node, sizeof(*latest_node)-8);
	if (crc != je32_to_cpu(latest_node->node_crc)) {
		JFFS2_ERROR("CRC failed for read_inode of inode %u at physical location 0x%x\n",
			f->inocache->ino, ref_offset(rii.latest_ref));
		return -EIO;
	}

	switch(jemode_to_cpu(latest_node->mode) & S_IFMT) {
	case S_IFDIR:
		if (rii.mctime_ver > je32_to_cpu(latest_node->version)) {
			/* The times in the latest_node are actually older than
			   mctime in the latest dirent. Cheat. */
			latest_node->ctime = latest_node->mtime = cpu_to_je32(rii.latest_mctime);
		}
		break;


	case S_IFREG:
		/* If it was a regular file, truncate it to the latest node's isize */
		new_size = jffs2_truncate_fragtree(c, &f->fragtree, je32_to_cpu(latest_node->isize));
		if (new_size != je32_to_cpu(latest_node->isize)) {
			JFFS2_WARNING("Truncating ino #%u to %d bytes failed because it only had %d bytes to start with!\n",
				      f->inocache->ino, je32_to_cpu(latest_node->isize), new_size);
			latest_node->isize = cpu_to_je32(new_size);
		}
		break;

	case S_IFLNK:
		/* Hack to work around broken isize in old symlink code.
		   Remove this when dwmw2 comes to his senses and stops
		   symlinks from being an entirely gratuitous special
		   case. */
		if (!je32_to_cpu(latest_node->isize))
			latest_node->isize = latest_node->dsize;

		if (f->inocache->state != INO_STATE_CHECKING) {
			/* Symlink's inode data is the target path. Read it and
			 * keep in RAM to facilitate quick follow symlink
			 * operation. */
			uint32_t csize = je32_to_cpu(latest_node->csize);
			if (csize > JFFS2_MAX_NAME_LEN)
				return -ENAMETOOLONG;
			f->target = kmalloc(csize + 1, GFP_KERNEL);
			if (!f->target) {
				JFFS2_ERROR("can't allocate %u bytes of memory for the symlink target path cache\n", csize);
				return -ENOMEM;
			}

			ret = jffs2_flash_read(c, ref_offset(rii.latest_ref) + sizeof(*latest_node),
					       csize, &retlen, (char *)f->target);

			if (ret || retlen != csize) {
				if (retlen != csize)
					ret = -EIO;
				kfree(f->target);
				f->target = NULL;
				return ret;
			}

			f->target[csize] = '\0';
			dbg_readinode("symlink's target '%s' cached\n", f->target);
		}

		/* fall through... */

	case S_IFBLK:
	case S_IFCHR:
		/* Certain inode types should have only one data node, and it's
		   kept as the metadata node */
		if (f->metadata) {
			JFFS2_ERROR("Argh. Special inode #%u with mode 0%o had metadata node\n",
			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
			return -EIO;
		}
		if (!frag_first(&f->fragtree)) {
			JFFS2_ERROR("Argh. Special inode #%u with mode 0%o has no fragments\n",
			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
			return -EIO;
		}
		/* ASSERT: f->fraglist != NULL */
		if (frag_next(frag_first(&f->fragtree))) {
			JFFS2_ERROR("Argh. Special inode #%u with mode 0x%x had more than one node\n",
			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
			/* FIXME: Deal with it - check crc32, check for duplicate node, check times and discard the older one */
			return -EIO;
		}
		/* OK. We're happy */
		f->metadata = frag_first(&f->fragtree)->node;
		jffs2_free_node_frag(frag_first(&f->fragtree));
		f->fragtree = RB_ROOT;
		break;
	}
	if (f->inocache->state == INO_STATE_READING)
		jffs2_set_inocache_state(c, f->inocache, INO_STATE_PRESENT);

	return 0;
}

/* Scan the list of all nodes present for this ino, build map of versions, etc. */
int jffs2_do_read_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
			uint32_t ino, struct jffs2_raw_inode *latest_node)
{
	dbg_readinode("read inode #%u\n", ino);

 retry_inocache:
	spin_lock(&c->inocache_lock);
	f->inocache = jffs2_get_ino_cache(c, ino);

	if (f->inocache) {
		/* Check its state. We may need to wait before we can use it */
		switch(f->inocache->state) {
		case INO_STATE_UNCHECKED:
		case INO_STATE_CHECKEDABSENT:
			f->inocache->state = INO_STATE_READING;
			break;

		case INO_STATE_CHECKING:
		case INO_STATE_GC:
			/* If it's in either of these states, we need
			   to wait for whoever's got it to finish and
			   put it back. */
			dbg_readinode("waiting for ino #%u in state %d\n", ino, f->inocache->state);
			sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
			goto retry_inocache;

		case INO_STATE_READING:
		case INO_STATE_PRESENT:
			/* Eep. This should never happen. It can
			happen if Linux calls read_inode() again
			before clear_inode() has finished though. */
			JFFS2_ERROR("Eep. Trying to read_inode #%u when it's already in state %d!\n", ino, f->inocache->state);
			/* Fail. That's probably better than allowing it to succeed */
			f->inocache = NULL;
			break;

		default:
			BUG();
		}
	}
	spin_unlock(&c->inocache_lock);

	if (!f->inocache && ino == 1) {
		/* Special case - no root inode on medium */
		f->inocache = jffs2_alloc_inode_cache();
		if (!f->inocache) {
			JFFS2_ERROR("cannot allocate inocache for root inode\n");
			return -ENOMEM;
		}
		dbg_readinode("creating inocache for root inode\n");
		memset(f->inocache, 0, sizeof(struct jffs2_inode_cache));
		f->inocache->ino = f->inocache->pino_nlink = 1;
		f->inocache->nodes = (struct jffs2_raw_node_ref *)f->inocache;
		f->inocache->state = INO_STATE_READING;
		jffs2_add_ino_cache(c, f->inocache);
	}
	if (!f->inocache) {
		JFFS2_ERROR("requested to read a nonexistent ino %u\n", ino);
		return -ENOENT;
	}

	return jffs2_do_read_inode_internal(c, f, latest_node);
}

int jffs2_do_crccheck_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
{
	struct jffs2_raw_inode n;
	struct jffs2_inode_info *f = kzalloc(sizeof(*f), GFP_KERNEL);
	int ret;

	if (!f)
		return -ENOMEM;

	mutex_init(&f->sem);
	mutex_lock(&f->sem);
	f->inocache = ic;

	ret = jffs2_do_read_inode_internal(c, f, &n);
	mutex_unlock(&f->sem);
	jffs2_do_clear_inode(c, f);
	jffs2_xattr_do_crccheck_inode(c, ic);
	kfree (f);
	return ret;
}

void jffs2_do_clear_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f)
{
	struct jffs2_full_dirent *fd, *fds;
	int deleted;

	jffs2_xattr_delete_inode(c, f->inocache);
	mutex_lock(&f->sem);
	deleted = f->inocache && !f->inocache->pino_nlink;

	if (f->inocache && f->inocache->state != INO_STATE_CHECKING)
		jffs2_set_inocache_state(c, f->inocache, INO_STATE_CLEARING);

	if (f->metadata) {
		if (deleted)
			jffs2_mark_node_obsolete(c, f->metadata->raw);
		jffs2_free_full_dnode(f->metadata);
	}

	jffs2_kill_fragtree(&f->fragtree, deleted?c:NULL);

	if (f->target) {
		kfree(f->target);
		f->target = NULL;
	}

	fds = f->dents;
	while(fds) {
		fd = fds;
		fds = fd->next;
		jffs2_free_full_dirent(fd);
	}

	if (f->inocache && f->inocache->state != INO_STATE_CHECKING) {
		jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
		if (f->inocache->nodes == (void *)f->inocache)
			jffs2_del_ino_cache(c, f->inocache);
	}

	mutex_unlock(&f->sem);
}