aboutsummaryrefslogtreecommitdiffstats
path: root/fs/jffs2/readinode.c
blob: cf39bcf3e3cf6634bf091b499836749f2deeeaf1 (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
/*
 * 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: readinode.c,v 1.126 2005/07/17 06:56:21 dedekind Exp $
 *
 */

#include <linux/kernel.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"

static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *list, struct jffs2_node_frag *newfrag);

static 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 */
			D2(printk(KERN_DEBUG "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 {
			D2(printk(KERN_DEBUG "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);
}

/* Given an inode, probably with existing list of fragments, add the new node
 * to the fragment list.
 */
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;

	D1(printk(KERN_DEBUG "jffs2_add_full_dnode_to_inode(ino #%u, f %p, fn %p)\n", f->inocache->ino, f, fn));

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

	newfrag = jffs2_alloc_node_frag();
	if (unlikely(!newfrag))
		return -ENOMEM;

	D2(printk(KERN_DEBUG "adding node %04x-%04x @0x%08x on flash, newfrag *%p\n",
		  fn->ofs, fn->ofs+fn->size, ref_offset(fn->raw), newfrag));
	
	newfrag->ofs = fn->ofs;
	newfrag->size = fn->size;
	newfrag->node = fn;
	newfrag->node->frags = 1;

	ret = jffs2_add_frag_to_fragtree(c, &f->fragtree, newfrag);
	if (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);
		}
	}
	D2(jffs2_dbg_fragtree_paranoia_check(f));
	D2(jffs2_dbg_dump_fragtree(f));
	return 0;
}

/* Doesn't set inode->i_size */
static int jffs2_add_frag_to_fragtree(struct jffs2_sb_info *c, struct rb_root *list, 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(list, newfrag->node->ofs);

	if (this) {
		D2(printk(KERN_DEBUG "j_a_f_d_t_f: 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 {
		D2(printk(KERN_DEBUG "j_a_f_d_t_f: Lookup gave no frag\n"));
		lastend = 0;
	}
			  
	/* See if we ran off the end of the list */
	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);
		}

		if (lastend < newfrag->node->ofs) {
			/* ... and we need to put a hole in before the new node */
			struct jffs2_node_frag *holefrag = jffs2_alloc_node_frag();
			if (!holefrag) {
				jffs2_free_node_frag(newfrag);
				return -ENOMEM;
			}
			holefrag->ofs = lastend;
			holefrag->size = newfrag->node->ofs - lastend;
			holefrag->node = NULL;
			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 */
				D2(printk(KERN_DEBUG "Adding hole frag (%p) on right of node at (%p)\n", holefrag, this));
				rb_link_node(&holefrag->rb, &this->rb, &this->rb.rb_right);
			} else {
				D2(printk(KERN_DEBUG "Adding hole frag (%p) at root of tree\n", holefrag));
				rb_link_node(&holefrag->rb, NULL, &list->rb_node);
			}
			rb_insert_color(&holefrag->rb, list);
			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 the hole */
			D2(printk(KERN_DEBUG "Adding new frag (%p) on right of node at (%p)\n", newfrag, this));
			rb_link_node(&newfrag->rb, &this->rb, &this->rb.rb_right);			
		} else {
			D2(printk(KERN_DEBUG "Adding new frag (%p) at root of tree\n", newfrag));
			rb_link_node(&newfrag->rb, NULL, &list->rb_node);
		}
		rb_insert_color(&newfrag->rb, list);
		return 0;
	}

	D2(printk(KERN_DEBUG "j_a_f_d_t_f: dealing with 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));

	/* 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 = jffs2_alloc_node_frag();
			if (!newfrag2) {
				jffs2_free_node_frag(newfrag);
				return -ENOMEM;
			}
			D2(printk(KERN_DEBUG "split old frag 0x%04x-0x%04x -->", this->ofs, this->ofs+this->size);
			if (this->node)
				printk("phys 0x%08x\n", ref_offset(this->node->raw));
			else 
				printk("hole\n");
			   )
			
			/* New second frag pointing to this's node */
			newfrag2->ofs = newfrag->ofs + newfrag->size;
			newfrag2->size = (this->ofs+this->size) - newfrag2->ofs;
			newfrag2->node = this->node;
			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, list);
			
			jffs2_fragtree_insert(newfrag2, newfrag);
			rb_insert_color(&newfrag2->rb, list);
			
			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, list);
	} else {
		/* New frag starts at the same point as 'this' used to. Replace 
		   it in the tree without doing a delete and insertion */
		D2(printk(KERN_DEBUG "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, list);
		
		if (newfrag->ofs + newfrag->size >= this->ofs+this->size) {
			D2(printk(KERN_DEBUG "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, list);
			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. */
		D2(printk(KERN_DEBUG "Obsoleting node frag %p (%x-%x) and removing from tree\n", this, this->ofs, this->ofs+this->size));
		rb_erase(&this->rb, list);
		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;
}

void jffs2_truncate_fraglist (struct jffs2_sb_info *c, struct rb_root *list, uint32_t size)
{
	struct jffs2_node_frag *frag = jffs2_lookup_node_frag(list, size);

	D1(printk(KERN_DEBUG "Truncating fraglist 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) {
			D1(printk(KERN_DEBUG "Truncating frag 0x%08x-0x%08x\n", frag->ofs, frag->ofs+frag->size));
			frag->size = size - frag->ofs;
		}
		frag = frag_next(frag);
	}
	while (frag && frag->ofs >= size) {
		struct jffs2_node_frag *next = frag_next(frag);

		D1(printk(KERN_DEBUG "Removing frag 0x%08x-0x%08x\n", frag->ofs, frag->ofs+frag->size));
		frag_erase(frag, list);
		jffs2_obsolete_node_frag(c, frag);
		frag = next;
	}
}

/* Scan the list of all nodes present for this ino, build map of versions, etc. */

static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c, 
					struct jffs2_inode_info *f,
					struct jffs2_raw_inode *latest_node);

int jffs2_do_read_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 
			uint32_t ino, struct jffs2_raw_inode *latest_node)
{
	D2(printk(KERN_DEBUG "jffs2_do_read_inode(): getting inocache\n"));

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

	D2(printk(KERN_DEBUG "jffs2_do_read_inode(): Got inocache at %p\n", f->inocache));

	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. */
			D1(printk(KERN_DEBUG "jffs2_get_ino_cache_read 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. */
			printk(KERN_WARNING "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) {
			printk(KERN_CRIT "jffs2_do_read_inode(): Cannot allocate inocache for root inode\n");
			return -ENOMEM;
		}
		D1(printk(KERN_DEBUG "jffs2_do_read_inode(): Creating inocache for root inode\n"));
		memset(f->inocache, 0, sizeof(struct jffs2_inode_cache));
		f->inocache->ino = f->inocache->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) {
		printk(KERN_WARNING "jffs2_do_read_inode() on 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 = kmalloc(sizeof(*f), GFP_KERNEL);
	int ret;

	if (!f)
		return -ENOMEM;

	memset(f, 0, sizeof(*f));
	init_MUTEX_LOCKED(&f->sem);
	f->inocache = ic;

	ret = jffs2_do_read_inode_internal(c, f, &n);
	if (!ret) {
		up(&f->sem);
		jffs2_do_clear_inode(c, f);
	}
	kfree (f);
	return ret;
}

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_tmp_dnode_info *tn = NULL;
	struct rb_root tn_list;
	struct rb_node *rb, *repl_rb;
	struct jffs2_full_dirent *fd_list;
	struct jffs2_full_dnode *fn = NULL;
	uint32_t crc;
	uint32_t latest_mctime, mctime_ver;
	uint32_t mdata_ver = 0;
	size_t retlen;
	int ret;

	D1(printk(KERN_DEBUG "jffs2_do_read_inode_internal(): ino #%u nlink is %d\n", f->inocache->ino, f->inocache->nlink));

	/* Grab all nodes relevant to this ino */
	ret = jffs2_get_inode_nodes(c, f, &tn_list, &fd_list, &f->highest_version, &latest_mctime, &mctime_ver);

	if (ret) {
		printk(KERN_CRIT "jffs2_get_inode_nodes() for ino %u returned %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;
	}
	f->dents = fd_list;

	rb = rb_first(&tn_list);

	while (rb) {
		tn = rb_entry(rb, struct jffs2_tmp_dnode_info, rb);
		fn = tn->fn;

		if (f->metadata) {
			if (likely(tn->version >= mdata_ver)) {
				D1(printk(KERN_DEBUG "Obsoleting old metadata at 0x%08x\n", ref_offset(f->metadata->raw)));
				jffs2_mark_node_obsolete(c, f->metadata->raw);
				jffs2_free_full_dnode(f->metadata);
				f->metadata = NULL;
				
				mdata_ver = 0;
			} else {
				/* This should never happen. */
				printk(KERN_WARNING "Er. New metadata at 0x%08x with ver %d is actually older than previous ver %d at 0x%08x\n",
					  ref_offset(fn->raw), tn->version, mdata_ver, ref_offset(f->metadata->raw));
				jffs2_mark_node_obsolete(c, fn->raw);
				jffs2_free_full_dnode(fn);
				/* Fill in latest_node from the metadata, not this one we're about to free... */
				fn = f->metadata;
				goto next_tn;
			}
		}

		if (fn->size) {
			jffs2_add_full_dnode_to_inode(c, f, fn);
		} else {
			/* Zero-sized node at end of version list. Just a metadata update */
			D1(printk(KERN_DEBUG "metadata @%08x: ver %d\n", ref_offset(fn->raw), tn->version));
			f->metadata = fn;
			mdata_ver = tn->version;
		}
	next_tn:
		BUG_ON(rb->rb_left);
		if (rb->rb_parent && rb->rb_parent->rb_left == rb) {
			/* We were then left-hand child of our parent. We need
			   to move our own right-hand child into our place. */
			repl_rb = rb->rb_right;
			if (repl_rb)
				repl_rb->rb_parent = rb->rb_parent;
		} else
			repl_rb = NULL;

		rb = rb_next(rb);

		/* Remove the spent tn from the tree; don't bother rebalancing
		   but put our right-hand child in our own place. */
		if (tn->rb.rb_parent) {
			if (tn->rb.rb_parent->rb_left == &tn->rb)
				tn->rb.rb_parent->rb_left = repl_rb;
			else if (tn->rb.rb_parent->rb_right == &tn->rb)
				tn->rb.rb_parent->rb_right = repl_rb;
			else BUG();
		} else if (tn->rb.rb_right)
			tn->rb.rb_right->rb_parent = NULL;

		jffs2_free_tmp_dnode_info(tn);
	}
	jffs2_dbg_fragtree_paranoia_check(f);

	if (!fn) {
		/* No data nodes for this inode. */
		if (f->inocache->ino != 1) {
			printk(KERN_WARNING "jffs2_do_read_inode(): No data nodes found for ino #%u\n", f->inocache->ino);
			if (!fd_list) {
				if (f->inocache->state == INO_STATE_READING)
					jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
				return -EIO;
			}
			printk(KERN_WARNING "jffs2_do_read_inode(): 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(fn->raw), sizeof(*latest_node), &retlen, (void *)latest_node);
	if (ret || retlen != sizeof(*latest_node)) {
		printk(KERN_NOTICE "MTD read in jffs2_do_read_inode() failed: Returned %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. */
		up(&f->sem);
		jffs2_do_clear_inode(c, f);
		return ret?ret:-EIO;
	}

	crc = crc32(0, latest_node, sizeof(*latest_node)-8);
	if (crc != je32_to_cpu(latest_node->node_crc)) {
		printk(KERN_NOTICE "CRC failed for read_inode of inode %u at physical location 0x%x\n", f->inocache->ino, ref_offset(fn->raw));
		up(&f->sem);
		jffs2_do_clear_inode(c, f);
		return -EIO;
	}

	switch(jemode_to_cpu(latest_node->mode) & S_IFMT) {
	case S_IFDIR:
		if (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(latest_mctime);
		}
		break;

			
	case S_IFREG:
		/* If it was a regular file, truncate it to the latest node's isize */
		jffs2_truncate_fraglist(c, &f->fragtree, je32_to_cpu(latest_node->isize));
		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.
			 * We use f->dents field to store the target path, which
			 * is somewhat ugly. */
			f->dents = kmalloc(je32_to_cpu(latest_node->csize) + 1, GFP_KERNEL);
			if (!f->dents) {
				printk(KERN_WARNING "Can't allocate %d bytes of memory "
						"for the symlink target path cache\n",
						je32_to_cpu(latest_node->csize));
				up(&f->sem);
				jffs2_do_clear_inode(c, f);
				return -ENOMEM;
			}
			
			ret = jffs2_flash_read(c, ref_offset(fn->raw) + sizeof(*latest_node),
						je32_to_cpu(latest_node->csize), &retlen, (char *)f->dents);
			
			if (ret  || retlen != je32_to_cpu(latest_node->csize)) {
				if (retlen != je32_to_cpu(latest_node->csize))
					ret = -EIO;
				kfree(f->dents);
				f->dents = NULL;
				up(&f->sem);
				jffs2_do_clear_inode(c, f);
				return -ret;
			}

			((char *)f->dents)[je32_to_cpu(latest_node->csize)] = '\0';
			D1(printk(KERN_DEBUG "jffs2_do_read_inode(): symlink's target '%s' cached\n",
						(char *)f->dents));
		}
		
		/* 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) {
			printk(KERN_WARNING "Argh. Special inode #%u with mode 0%o had metadata node\n",
			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
			up(&f->sem);
			jffs2_do_clear_inode(c, f);
			return -EIO;
		}
		if (!frag_first(&f->fragtree)) {
			printk(KERN_WARNING "Argh. Special inode #%u with mode 0%o has no fragments\n",
			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
			up(&f->sem);
			jffs2_do_clear_inode(c, f);
			return -EIO;
		}
		/* ASSERT: f->fraglist != NULL */
		if (frag_next(frag_first(&f->fragtree))) {
			printk(KERN_WARNING "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 */
			up(&f->sem);
			jffs2_do_clear_inode(c, f);
			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;
}

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

	down(&f->sem);
	deleted = f->inocache && !f->inocache->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);

	/* For symlink inodes we us f->dents to store the target path name */
	if (S_ISLNK(OFNI_EDONI_2SFFJ(f)->i_mode)) {
		if (f->dents) {
			kfree(f->dents);
			f->dents = NULL;
		}
	} else {
		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);
	}

	up(&f->sem);
}