xref: /openbmc/linux/fs/jffs2/readinode.c (revision 9afc9a8a)
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright © 2001-2007 Red Hat, Inc.
5  *
6  * Created by David Woodhouse <dwmw2@infradead.org>
7  *
8  * For licensing information, see the file 'LICENCE' in this directory.
9  *
10  */
11 
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/slab.h>
17 #include <linux/fs.h>
18 #include <linux/crc32.h>
19 #include <linux/pagemap.h>
20 #include <linux/mtd/mtd.h>
21 #include <linux/compiler.h>
22 #include "nodelist.h"
23 
24 /*
25  * Check the data CRC of the node.
26  *
27  * Returns: 0 if the data CRC is correct;
28  * 	    1 - if incorrect;
29  *	    error code if an error occurred.
30  */
check_node_data(struct jffs2_sb_info * c,struct jffs2_tmp_dnode_info * tn)31 static int check_node_data(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
32 {
33 	struct jffs2_raw_node_ref *ref = tn->fn->raw;
34 	int err = 0, pointed = 0;
35 	struct jffs2_eraseblock *jeb;
36 	unsigned char *buffer;
37 	uint32_t crc, ofs, len;
38 	size_t retlen;
39 
40 	BUG_ON(tn->csize == 0);
41 
42 	/* Calculate how many bytes were already checked */
43 	ofs = ref_offset(ref) + sizeof(struct jffs2_raw_inode);
44 	len = tn->csize;
45 
46 	if (jffs2_is_writebuffered(c)) {
47 		int adj = ofs % c->wbuf_pagesize;
48 		if (likely(adj))
49 			adj = c->wbuf_pagesize - adj;
50 
51 		if (adj >= tn->csize) {
52 			dbg_readinode("no need to check node at %#08x, data length %u, data starts at %#08x - it has already been checked.\n",
53 				      ref_offset(ref), tn->csize, ofs);
54 			goto adj_acc;
55 		}
56 
57 		ofs += adj;
58 		len -= adj;
59 	}
60 
61 	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",
62 		ref_offset(ref), tn->csize, tn->partial_crc, tn->data_crc, ofs - len, ofs, len);
63 
64 #ifndef __ECOS
65 	/* TODO: instead, incapsulate point() stuff to jffs2_flash_read(),
66 	 * adding and jffs2_flash_read_end() interface. */
67 	err = mtd_point(c->mtd, ofs, len, &retlen, (void **)&buffer, NULL);
68 	if (!err && retlen < len) {
69 		JFFS2_WARNING("MTD point returned len too short: %zu instead of %u.\n", retlen, tn->csize);
70 		mtd_unpoint(c->mtd, ofs, retlen);
71 	} else if (err) {
72 		if (err != -EOPNOTSUPP)
73 			JFFS2_WARNING("MTD point failed: error code %d.\n", err);
74 	} else
75 		pointed = 1; /* succefully pointed to device */
76 #endif
77 
78 	if (!pointed) {
79 		buffer = kmalloc(len, GFP_KERNEL);
80 		if (unlikely(!buffer))
81 			return -ENOMEM;
82 
83 		/* TODO: this is very frequent pattern, make it a separate
84 		 * routine */
85 		err = jffs2_flash_read(c, ofs, len, &retlen, buffer);
86 		if (err) {
87 			JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ofs, err);
88 			goto free_out;
89 		}
90 
91 		if (retlen != len) {
92 			JFFS2_ERROR("short read at %#08x: %zd instead of %d.\n", ofs, retlen, len);
93 			err = -EIO;
94 			goto free_out;
95 		}
96 	}
97 
98 	/* Continue calculating CRC */
99 	crc = crc32(tn->partial_crc, buffer, len);
100 	if(!pointed)
101 		kfree(buffer);
102 #ifndef __ECOS
103 	else
104 		mtd_unpoint(c->mtd, ofs, len);
105 #endif
106 
107 	if (crc != tn->data_crc) {
108 		JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
109 			     ref_offset(ref), tn->data_crc, crc);
110 		return 1;
111 	}
112 
113 adj_acc:
114 	jeb = &c->blocks[ref->flash_offset / c->sector_size];
115 	len = ref_totlen(c, jeb, ref);
116 	/* If it should be REF_NORMAL, it'll get marked as such when
117 	   we build the fragtree, shortly. No need to worry about GC
118 	   moving it while it's marked REF_PRISTINE -- GC won't happen
119 	   till we've finished checking every inode anyway. */
120 	ref->flash_offset |= REF_PRISTINE;
121 	/*
122 	 * Mark the node as having been checked and fix the
123 	 * accounting accordingly.
124 	 */
125 	spin_lock(&c->erase_completion_lock);
126 	jeb->used_size += len;
127 	jeb->unchecked_size -= len;
128 	c->used_size += len;
129 	c->unchecked_size -= len;
130 	jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
131 	spin_unlock(&c->erase_completion_lock);
132 
133 	return 0;
134 
135 free_out:
136 	if(!pointed)
137 		kfree(buffer);
138 #ifndef __ECOS
139 	else
140 		mtd_unpoint(c->mtd, ofs, len);
141 #endif
142 	return err;
143 }
144 
145 /*
146  * Helper function for jffs2_add_older_frag_to_fragtree().
147  *
148  * Checks the node if we are in the checking stage.
149  */
check_tn_node(struct jffs2_sb_info * c,struct jffs2_tmp_dnode_info * tn)150 static int check_tn_node(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
151 {
152 	int ret;
153 
154 	BUG_ON(ref_obsolete(tn->fn->raw));
155 
156 	/* We only check the data CRC of unchecked nodes */
157 	if (ref_flags(tn->fn->raw) != REF_UNCHECKED)
158 		return 0;
159 
160 	dbg_readinode("check node %#04x-%#04x, phys offs %#08x\n",
161 		      tn->fn->ofs, tn->fn->ofs + tn->fn->size, ref_offset(tn->fn->raw));
162 
163 	ret = check_node_data(c, tn);
164 	if (unlikely(ret < 0)) {
165 		JFFS2_ERROR("check_node_data() returned error: %d.\n",
166 			ret);
167 	} else if (unlikely(ret > 0)) {
168 		dbg_readinode("CRC error, mark it obsolete.\n");
169 		jffs2_mark_node_obsolete(c, tn->fn->raw);
170 	}
171 
172 	return ret;
173 }
174 
jffs2_lookup_tn(struct rb_root * tn_root,uint32_t offset)175 static struct jffs2_tmp_dnode_info *jffs2_lookup_tn(struct rb_root *tn_root, uint32_t offset)
176 {
177 	struct rb_node *next;
178 	struct jffs2_tmp_dnode_info *tn = NULL;
179 
180 	dbg_readinode("root %p, offset %d\n", tn_root, offset);
181 
182 	next = tn_root->rb_node;
183 
184 	while (next) {
185 		tn = rb_entry(next, struct jffs2_tmp_dnode_info, rb);
186 
187 		if (tn->fn->ofs < offset)
188 			next = tn->rb.rb_right;
189 		else if (tn->fn->ofs >= offset)
190 			next = tn->rb.rb_left;
191 		else
192 			break;
193 	}
194 
195 	return tn;
196 }
197 
198 
jffs2_kill_tn(struct jffs2_sb_info * c,struct jffs2_tmp_dnode_info * tn)199 static void jffs2_kill_tn(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
200 {
201 	jffs2_mark_node_obsolete(c, tn->fn->raw);
202 	jffs2_free_full_dnode(tn->fn);
203 	jffs2_free_tmp_dnode_info(tn);
204 }
205 /*
206  * This function is used when we read an inode. Data nodes arrive in
207  * arbitrary order -- they may be older or newer than the nodes which
208  * are already in the tree. Where overlaps occur, the older node can
209  * be discarded as long as the newer passes the CRC check. We don't
210  * bother to keep track of holes in this rbtree, and neither do we deal
211  * with frags -- we can have multiple entries starting at the same
212  * offset, and the one with the smallest length will come first in the
213  * ordering.
214  *
215  * Returns 0 if the node was handled (including marking it obsolete)
216  *	 < 0 an if error occurred
217  */
jffs2_add_tn_to_tree(struct jffs2_sb_info * c,struct jffs2_readinode_info * rii,struct jffs2_tmp_dnode_info * tn)218 static int jffs2_add_tn_to_tree(struct jffs2_sb_info *c,
219 				struct jffs2_readinode_info *rii,
220 				struct jffs2_tmp_dnode_info *tn)
221 {
222 	uint32_t fn_end = tn->fn->ofs + tn->fn->size;
223 	struct jffs2_tmp_dnode_info *this, *ptn;
224 
225 	dbg_readinode("insert fragment %#04x-%#04x, ver %u at %08x\n", tn->fn->ofs, fn_end, tn->version, ref_offset(tn->fn->raw));
226 
227 	/* If a node has zero dsize, we only have to keep it if it might be the
228 	   node with highest version -- i.e. the one which will end up as f->metadata.
229 	   Note that such nodes won't be REF_UNCHECKED since there are no data to
230 	   check anyway. */
231 	if (!tn->fn->size) {
232 		if (rii->mdata_tn) {
233 			if (rii->mdata_tn->version < tn->version) {
234 				/* We had a candidate mdata node already */
235 				dbg_readinode("kill old mdata with ver %d\n", rii->mdata_tn->version);
236 				jffs2_kill_tn(c, rii->mdata_tn);
237 			} else {
238 				dbg_readinode("kill new mdata with ver %d (older than existing %d\n",
239 					      tn->version, rii->mdata_tn->version);
240 				jffs2_kill_tn(c, tn);
241 				return 0;
242 			}
243 		}
244 		rii->mdata_tn = tn;
245 		dbg_readinode("keep new mdata with ver %d\n", tn->version);
246 		return 0;
247 	}
248 
249 	/* Find the earliest node which _may_ be relevant to this one */
250 	this = jffs2_lookup_tn(&rii->tn_root, tn->fn->ofs);
251 	if (this) {
252 		/* If the node is coincident with another at a lower address,
253 		   back up until the other node is found. It may be relevant */
254 		while (this->overlapped) {
255 			ptn = tn_prev(this);
256 			if (!ptn) {
257 				/*
258 				 * We killed a node which set the overlapped
259 				 * flags during the scan. Fix it up.
260 				 */
261 				this->overlapped = 0;
262 				break;
263 			}
264 			this = ptn;
265 		}
266 		dbg_readinode("'this' found %#04x-%#04x (%s)\n", this->fn->ofs, this->fn->ofs + this->fn->size, this->fn ? "data" : "hole");
267 	}
268 
269 	while (this) {
270 		if (this->fn->ofs > fn_end)
271 			break;
272 		dbg_readinode("Ponder this ver %d, 0x%x-0x%x\n",
273 			      this->version, this->fn->ofs, this->fn->size);
274 
275 		if (this->version == tn->version) {
276 			/* Version number collision means REF_PRISTINE GC. Accept either of them
277 			   as long as the CRC is correct. Check the one we have already...  */
278 			if (!check_tn_node(c, this)) {
279 				/* The one we already had was OK. Keep it and throw away the new one */
280 				dbg_readinode("Like old node. Throw away new\n");
281 				jffs2_kill_tn(c, tn);
282 				return 0;
283 			} else {
284 				/* Who cares if the new one is good; keep it for now anyway. */
285 				dbg_readinode("Like new node. Throw away old\n");
286 				rb_replace_node(&this->rb, &tn->rb, &rii->tn_root);
287 				jffs2_kill_tn(c, this);
288 				/* Same overlapping from in front and behind */
289 				return 0;
290 			}
291 		}
292 		if (this->version < tn->version &&
293 		    this->fn->ofs >= tn->fn->ofs &&
294 		    this->fn->ofs + this->fn->size <= fn_end) {
295 			/* New node entirely overlaps 'this' */
296 			if (check_tn_node(c, tn)) {
297 				dbg_readinode("new node bad CRC\n");
298 				jffs2_kill_tn(c, tn);
299 				return 0;
300 			}
301 			/* ... and is good. Kill 'this' and any subsequent nodes which are also overlapped */
302 			while (this && this->fn->ofs + this->fn->size <= fn_end) {
303 				struct jffs2_tmp_dnode_info *next = tn_next(this);
304 				if (this->version < tn->version) {
305 					tn_erase(this, &rii->tn_root);
306 					dbg_readinode("Kill overlapped ver %d, 0x%x-0x%x\n",
307 						      this->version, this->fn->ofs,
308 						      this->fn->ofs+this->fn->size);
309 					jffs2_kill_tn(c, this);
310 				}
311 				this = next;
312 			}
313 			dbg_readinode("Done killing overlapped nodes\n");
314 			continue;
315 		}
316 		if (this->version > tn->version &&
317 		    this->fn->ofs <= tn->fn->ofs &&
318 		    this->fn->ofs+this->fn->size >= fn_end) {
319 			/* New node entirely overlapped by 'this' */
320 			if (!check_tn_node(c, this)) {
321 				dbg_readinode("Good CRC on old node. Kill new\n");
322 				jffs2_kill_tn(c, tn);
323 				return 0;
324 			}
325 			/* ... but 'this' was bad. Replace it... */
326 			dbg_readinode("Bad CRC on old overlapping node. Kill it\n");
327 			tn_erase(this, &rii->tn_root);
328 			jffs2_kill_tn(c, this);
329 			break;
330 		}
331 
332 		this = tn_next(this);
333 	}
334 
335 	/* We neither completely obsoleted nor were completely
336 	   obsoleted by an earlier node. Insert into the tree */
337 	{
338 		struct rb_node *parent;
339 		struct rb_node **link = &rii->tn_root.rb_node;
340 		struct jffs2_tmp_dnode_info *insert_point = NULL;
341 
342 		while (*link) {
343 			parent = *link;
344 			insert_point = rb_entry(parent, struct jffs2_tmp_dnode_info, rb);
345 			if (tn->fn->ofs > insert_point->fn->ofs)
346 				link = &insert_point->rb.rb_right;
347 			else if (tn->fn->ofs < insert_point->fn->ofs ||
348 				 tn->fn->size < insert_point->fn->size)
349 				link = &insert_point->rb.rb_left;
350 			else
351 				link = &insert_point->rb.rb_right;
352 		}
353 		rb_link_node(&tn->rb, &insert_point->rb, link);
354 		rb_insert_color(&tn->rb, &rii->tn_root);
355 	}
356 
357 	/* If there's anything behind that overlaps us, note it */
358 	this = tn_prev(tn);
359 	if (this) {
360 		while (1) {
361 			if (this->fn->ofs + this->fn->size > tn->fn->ofs) {
362 				dbg_readinode("Node is overlapped by %p (v %d, 0x%x-0x%x)\n",
363 					      this, this->version, this->fn->ofs,
364 					      this->fn->ofs+this->fn->size);
365 				tn->overlapped = 1;
366 				break;
367 			}
368 			if (!this->overlapped)
369 				break;
370 
371 			ptn = tn_prev(this);
372 			if (!ptn) {
373 				/*
374 				 * We killed a node which set the overlapped
375 				 * flags during the scan. Fix it up.
376 				 */
377 				this->overlapped = 0;
378 				break;
379 			}
380 			this = ptn;
381 		}
382 	}
383 
384 	/* If the new node overlaps anything ahead, note it */
385 	this = tn_next(tn);
386 	while (this && this->fn->ofs < fn_end) {
387 		this->overlapped = 1;
388 		dbg_readinode("Node ver %d, 0x%x-0x%x is overlapped\n",
389 			      this->version, this->fn->ofs,
390 			      this->fn->ofs+this->fn->size);
391 		this = tn_next(this);
392 	}
393 	return 0;
394 }
395 
396 /* Trivial function to remove the last node in the tree. Which by definition
397    has no right-hand child — so can be removed just by making its left-hand
398    child (if any) take its place under its parent. Since this is only done
399    when we're consuming the whole tree, there's no need to use rb_erase()
400    and let it worry about adjusting colours and balancing the tree. That
401    would just be a waste of time. */
eat_last(struct rb_root * root,struct rb_node * node)402 static void eat_last(struct rb_root *root, struct rb_node *node)
403 {
404 	struct rb_node *parent = rb_parent(node);
405 	struct rb_node **link;
406 
407 	/* LAST! */
408 	BUG_ON(node->rb_right);
409 
410 	if (!parent)
411 		link = &root->rb_node;
412 	else if (node == parent->rb_left)
413 		link = &parent->rb_left;
414 	else
415 		link = &parent->rb_right;
416 
417 	*link = node->rb_left;
418 	if (node->rb_left)
419 		node->rb_left->__rb_parent_color = node->__rb_parent_color;
420 }
421 
422 /* We put the version tree in reverse order, so we can use the same eat_last()
423    function that we use to consume the tmpnode tree (tn_root). */
ver_insert(struct rb_root * ver_root,struct jffs2_tmp_dnode_info * tn)424 static void ver_insert(struct rb_root *ver_root, struct jffs2_tmp_dnode_info *tn)
425 {
426 	struct rb_node **link = &ver_root->rb_node;
427 	struct rb_node *parent = NULL;
428 	struct jffs2_tmp_dnode_info *this_tn;
429 
430 	while (*link) {
431 		parent = *link;
432 		this_tn = rb_entry(parent, struct jffs2_tmp_dnode_info, rb);
433 
434 		if (tn->version > this_tn->version)
435 			link = &parent->rb_left;
436 		else
437 			link = &parent->rb_right;
438 	}
439 	dbg_readinode("Link new node at %p (root is %p)\n", link, ver_root);
440 	rb_link_node(&tn->rb, parent, link);
441 	rb_insert_color(&tn->rb, ver_root);
442 }
443 
444 /* Build final, normal fragtree from tn tree. It doesn't matter which order
445    we add nodes to the real fragtree, as long as they don't overlap. And
446    having thrown away the majority of overlapped nodes as we went, there
447    really shouldn't be many sets of nodes which do overlap. If we start at
448    the end, we can use the overlap markers -- we can just eat nodes which
449    aren't overlapped, and when we encounter nodes which _do_ overlap we
450    sort them all into a temporary tree in version order before replaying them. */
jffs2_build_inode_fragtree(struct jffs2_sb_info * c,struct jffs2_inode_info * f,struct jffs2_readinode_info * rii)451 static int jffs2_build_inode_fragtree(struct jffs2_sb_info *c,
452 				      struct jffs2_inode_info *f,
453 				      struct jffs2_readinode_info *rii)
454 {
455 	struct jffs2_tmp_dnode_info *pen, *last, *this;
456 	struct rb_root ver_root = RB_ROOT;
457 	uint32_t high_ver = 0;
458 
459 	if (rii->mdata_tn) {
460 		dbg_readinode("potential mdata is ver %d at %p\n", rii->mdata_tn->version, rii->mdata_tn);
461 		high_ver = rii->mdata_tn->version;
462 		rii->latest_ref = rii->mdata_tn->fn->raw;
463 	}
464 #ifdef JFFS2_DBG_READINODE_MESSAGES
465 	this = tn_last(&rii->tn_root);
466 	while (this) {
467 		dbg_readinode("tn %p ver %d range 0x%x-0x%x ov %d\n", this, this->version, this->fn->ofs,
468 			      this->fn->ofs+this->fn->size, this->overlapped);
469 		this = tn_prev(this);
470 	}
471 #endif
472 	pen = tn_last(&rii->tn_root);
473 	while ((last = pen)) {
474 		pen = tn_prev(last);
475 
476 		eat_last(&rii->tn_root, &last->rb);
477 		ver_insert(&ver_root, last);
478 
479 		if (unlikely(last->overlapped)) {
480 			if (pen)
481 				continue;
482 			/*
483 			 * We killed a node which set the overlapped
484 			 * flags during the scan. Fix it up.
485 			 */
486 			last->overlapped = 0;
487 		}
488 
489 		/* Now we have a bunch of nodes in reverse version
490 		   order, in the tree at ver_root. Most of the time,
491 		   there'll actually be only one node in the 'tree',
492 		   in fact. */
493 		this = tn_last(&ver_root);
494 
495 		while (this) {
496 			struct jffs2_tmp_dnode_info *vers_next;
497 			int ret;
498 			vers_next = tn_prev(this);
499 			eat_last(&ver_root, &this->rb);
500 			if (check_tn_node(c, this)) {
501 				dbg_readinode("node ver %d, 0x%x-0x%x failed CRC\n",
502 					     this->version, this->fn->ofs,
503 					     this->fn->ofs+this->fn->size);
504 				jffs2_kill_tn(c, this);
505 			} else {
506 				if (this->version > high_ver) {
507 					/* Note that this is different from the other
508 					   highest_version, because this one is only
509 					   counting _valid_ nodes which could give the
510 					   latest inode metadata */
511 					high_ver = this->version;
512 					rii->latest_ref = this->fn->raw;
513 				}
514 				dbg_readinode("Add %p (v %d, 0x%x-0x%x, ov %d) to fragtree\n",
515 					     this, this->version, this->fn->ofs,
516 					     this->fn->ofs+this->fn->size, this->overlapped);
517 
518 				ret = jffs2_add_full_dnode_to_inode(c, f, this->fn);
519 				if (ret) {
520 					/* Free the nodes in vers_root; let the caller
521 					   deal with the rest */
522 					JFFS2_ERROR("Add node to tree failed %d\n", ret);
523 					while (1) {
524 						vers_next = tn_prev(this);
525 						if (check_tn_node(c, this))
526 							jffs2_mark_node_obsolete(c, this->fn->raw);
527 						jffs2_free_full_dnode(this->fn);
528 						jffs2_free_tmp_dnode_info(this);
529 						this = vers_next;
530 						if (!this)
531 							break;
532 						eat_last(&ver_root, &vers_next->rb);
533 					}
534 					return ret;
535 				}
536 				jffs2_free_tmp_dnode_info(this);
537 			}
538 			this = vers_next;
539 		}
540 	}
541 	return 0;
542 }
543 
jffs2_free_tmp_dnode_info_list(struct rb_root * list)544 static void jffs2_free_tmp_dnode_info_list(struct rb_root *list)
545 {
546 	struct jffs2_tmp_dnode_info *tn, *next;
547 
548 	rbtree_postorder_for_each_entry_safe(tn, next, list, rb) {
549 			jffs2_free_full_dnode(tn->fn);
550 			jffs2_free_tmp_dnode_info(tn);
551 	}
552 
553 	*list = RB_ROOT;
554 }
555 
jffs2_free_full_dirent_list(struct jffs2_full_dirent * fd)556 static void jffs2_free_full_dirent_list(struct jffs2_full_dirent *fd)
557 {
558 	struct jffs2_full_dirent *next;
559 
560 	while (fd) {
561 		next = fd->next;
562 		jffs2_free_full_dirent(fd);
563 		fd = next;
564 	}
565 }
566 
567 /* Returns first valid node after 'ref'. May return 'ref' */
jffs2_first_valid_node(struct jffs2_raw_node_ref * ref)568 static struct jffs2_raw_node_ref *jffs2_first_valid_node(struct jffs2_raw_node_ref *ref)
569 {
570 	while (ref && ref->next_in_ino) {
571 		if (!ref_obsolete(ref))
572 			return ref;
573 		dbg_noderef("node at 0x%08x is obsoleted. Ignoring.\n", ref_offset(ref));
574 		ref = ref->next_in_ino;
575 	}
576 	return NULL;
577 }
578 
579 /*
580  * Helper function for jffs2_get_inode_nodes().
581  * It is called every time an directory entry node is found.
582  *
583  * Returns: 0 on success;
584  * 	    negative error code on failure.
585  */
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)586 static inline int read_direntry(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
587 				struct jffs2_raw_dirent *rd, size_t read,
588 				struct jffs2_readinode_info *rii)
589 {
590 	struct jffs2_full_dirent *fd;
591 	uint32_t crc;
592 
593 	/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
594 	BUG_ON(ref_obsolete(ref));
595 
596 	crc = crc32(0, rd, sizeof(*rd) - 8);
597 	if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
598 		JFFS2_NOTICE("header CRC failed on dirent node at %#08x: read %#08x, calculated %#08x\n",
599 			     ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
600 		jffs2_mark_node_obsolete(c, ref);
601 		return 0;
602 	}
603 
604 	/* If we've never checked the CRCs on this node, check them now */
605 	if (ref_flags(ref) == REF_UNCHECKED) {
606 		struct jffs2_eraseblock *jeb;
607 		int len;
608 
609 		/* Sanity check */
610 		if (unlikely(PAD((rd->nsize + sizeof(*rd))) != PAD(je32_to_cpu(rd->totlen)))) {
611 			JFFS2_ERROR("illegal nsize in node at %#08x: nsize %#02x, totlen %#04x\n",
612 				    ref_offset(ref), rd->nsize, je32_to_cpu(rd->totlen));
613 			jffs2_mark_node_obsolete(c, ref);
614 			return 0;
615 		}
616 
617 		jeb = &c->blocks[ref->flash_offset / c->sector_size];
618 		len = ref_totlen(c, jeb, ref);
619 
620 		spin_lock(&c->erase_completion_lock);
621 		jeb->used_size += len;
622 		jeb->unchecked_size -= len;
623 		c->used_size += len;
624 		c->unchecked_size -= len;
625 		ref->flash_offset = ref_offset(ref) | dirent_node_state(rd);
626 		spin_unlock(&c->erase_completion_lock);
627 	}
628 
629 	fd = jffs2_alloc_full_dirent(rd->nsize + 1);
630 	if (unlikely(!fd))
631 		return -ENOMEM;
632 
633 	fd->raw = ref;
634 	fd->version = je32_to_cpu(rd->version);
635 	fd->ino = je32_to_cpu(rd->ino);
636 	fd->type = rd->type;
637 
638 	if (fd->version > rii->highest_version)
639 		rii->highest_version = fd->version;
640 
641 	/* Pick out the mctime of the latest dirent */
642 	if(fd->version > rii->mctime_ver && je32_to_cpu(rd->mctime)) {
643 		rii->mctime_ver = fd->version;
644 		rii->latest_mctime = je32_to_cpu(rd->mctime);
645 	}
646 
647 	/*
648 	 * Copy as much of the name as possible from the raw
649 	 * dirent we've already read from the flash.
650 	 */
651 	if (read > sizeof(*rd))
652 		memcpy(&fd->name[0], &rd->name[0],
653 		       min_t(uint32_t, rd->nsize, (read - sizeof(*rd)) ));
654 
655 	/* Do we need to copy any more of the name directly from the flash? */
656 	if (rd->nsize + sizeof(*rd) > read) {
657 		/* FIXME: point() */
658 		int err;
659 		int already = read - sizeof(*rd);
660 
661 		err = jffs2_flash_read(c, (ref_offset(ref)) + read,
662 				rd->nsize - already, &read, &fd->name[already]);
663 		if (unlikely(read != rd->nsize - already) && likely(!err)) {
664 			jffs2_free_full_dirent(fd);
665 			JFFS2_ERROR("short read: wanted %d bytes, got %zd\n",
666 				    rd->nsize - already, read);
667 			return -EIO;
668 		}
669 
670 		if (unlikely(err)) {
671 			JFFS2_ERROR("read remainder of name: error %d\n", err);
672 			jffs2_free_full_dirent(fd);
673 			return -EIO;
674 		}
675 
676 #ifdef CONFIG_JFFS2_SUMMARY
677 		/*
678 		 * we use CONFIG_JFFS2_SUMMARY because without it, we
679 		 * have checked it while mounting
680 		 */
681 		crc = crc32(0, fd->name, rd->nsize);
682 		if (unlikely(crc != je32_to_cpu(rd->name_crc))) {
683 			JFFS2_NOTICE("name CRC failed on dirent node at"
684 			   "%#08x: read %#08x,calculated %#08x\n",
685 			   ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
686 			jffs2_mark_node_obsolete(c, ref);
687 			jffs2_free_full_dirent(fd);
688 			return 0;
689 		}
690 #endif
691 	}
692 
693 	fd->nhash = full_name_hash(NULL, fd->name, rd->nsize);
694 	fd->next = NULL;
695 	fd->name[rd->nsize] = '\0';
696 
697 	/*
698 	 * Wheee. We now have a complete jffs2_full_dirent structure, with
699 	 * the name in it and everything. Link it into the list
700 	 */
701 	jffs2_add_fd_to_list(c, fd, &rii->fds);
702 
703 	return 0;
704 }
705 
706 /*
707  * Helper function for jffs2_get_inode_nodes().
708  * It is called every time an inode node is found.
709  *
710  * Returns: 0 on success (possibly after marking a bad node obsolete);
711  * 	    negative error code on failure.
712  */
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)713 static inline int read_dnode(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
714 			     struct jffs2_raw_inode *rd, int rdlen,
715 			     struct jffs2_readinode_info *rii)
716 {
717 	struct jffs2_tmp_dnode_info *tn;
718 	uint32_t len, csize;
719 	int ret = 0;
720 	uint32_t crc;
721 
722 	/* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
723 	BUG_ON(ref_obsolete(ref));
724 
725 	crc = crc32(0, rd, sizeof(*rd) - 8);
726 	if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
727 		JFFS2_NOTICE("node CRC failed on dnode at %#08x: read %#08x, calculated %#08x\n",
728 			     ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
729 		jffs2_mark_node_obsolete(c, ref);
730 		return 0;
731 	}
732 
733 	tn = jffs2_alloc_tmp_dnode_info();
734 	if (!tn) {
735 		JFFS2_ERROR("failed to allocate tn (%zu bytes).\n", sizeof(*tn));
736 		return -ENOMEM;
737 	}
738 
739 	tn->partial_crc = 0;
740 	csize = je32_to_cpu(rd->csize);
741 
742 	/* If we've never checked the CRCs on this node, check them now */
743 	if (ref_flags(ref) == REF_UNCHECKED) {
744 
745 		/* Sanity checks */
746 		if (unlikely(je32_to_cpu(rd->offset) > je32_to_cpu(rd->isize)) ||
747 		    unlikely(PAD(je32_to_cpu(rd->csize) + sizeof(*rd)) != PAD(je32_to_cpu(rd->totlen)))) {
748 			JFFS2_WARNING("inode node header CRC is corrupted at %#08x\n", ref_offset(ref));
749 			jffs2_dbg_dump_node(c, ref_offset(ref));
750 			jffs2_mark_node_obsolete(c, ref);
751 			goto free_out;
752 		}
753 
754 		if (jffs2_is_writebuffered(c) && csize != 0) {
755 			/* At this point we are supposed to check the data CRC
756 			 * of our unchecked node. But thus far, we do not
757 			 * know whether the node is valid or obsolete. To
758 			 * figure this out, we need to walk all the nodes of
759 			 * the inode and build the inode fragtree. We don't
760 			 * want to spend time checking data of nodes which may
761 			 * later be found to be obsolete. So we put off the full
762 			 * data CRC checking until we have read all the inode
763 			 * nodes and have started building the fragtree.
764 			 *
765 			 * The fragtree is being built starting with nodes
766 			 * having the highest version number, so we'll be able
767 			 * to detect whether a node is valid (i.e., it is not
768 			 * overlapped by a node with higher version) or not.
769 			 * And we'll be able to check only those nodes, which
770 			 * are not obsolete.
771 			 *
772 			 * Of course, this optimization only makes sense in case
773 			 * of NAND flashes (or other flashes with
774 			 * !jffs2_can_mark_obsolete()), since on NOR flashes
775 			 * nodes are marked obsolete physically.
776 			 *
777 			 * Since NAND flashes (or other flashes with
778 			 * jffs2_is_writebuffered(c)) are anyway read by
779 			 * fractions of c->wbuf_pagesize, and we have just read
780 			 * the node header, it is likely that the starting part
781 			 * of the node data is also read when we read the
782 			 * header. So we don't mind to check the CRC of the
783 			 * starting part of the data of the node now, and check
784 			 * the second part later (in jffs2_check_node_data()).
785 			 * Of course, we will not need to re-read and re-check
786 			 * the NAND page which we have just read. This is why we
787 			 * read the whole NAND page at jffs2_get_inode_nodes(),
788 			 * while we needed only the node header.
789 			 */
790 			unsigned char *buf;
791 
792 			/* 'buf' will point to the start of data */
793 			buf = (unsigned char *)rd + sizeof(*rd);
794 			/* len will be the read data length */
795 			len = min_t(uint32_t, rdlen - sizeof(*rd), csize);
796 			tn->partial_crc = crc32(0, buf, len);
797 
798 			dbg_readinode("Calculates CRC (%#08x) for %d bytes, csize %d\n", tn->partial_crc, len, csize);
799 
800 			/* If we actually calculated the whole data CRC
801 			 * and it is wrong, drop the node. */
802 			if (len >= csize && unlikely(tn->partial_crc != je32_to_cpu(rd->data_crc))) {
803 				JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
804 					ref_offset(ref), tn->partial_crc, je32_to_cpu(rd->data_crc));
805 				jffs2_mark_node_obsolete(c, ref);
806 				goto free_out;
807 			}
808 
809 		} else if (csize == 0) {
810 			/*
811 			 * We checked the header CRC. If the node has no data, adjust
812 			 * the space accounting now. For other nodes this will be done
813 			 * later either when the node is marked obsolete or when its
814 			 * data is checked.
815 			 */
816 			struct jffs2_eraseblock *jeb;
817 
818 			dbg_readinode("the node has no data.\n");
819 			jeb = &c->blocks[ref->flash_offset / c->sector_size];
820 			len = ref_totlen(c, jeb, ref);
821 
822 			spin_lock(&c->erase_completion_lock);
823 			jeb->used_size += len;
824 			jeb->unchecked_size -= len;
825 			c->used_size += len;
826 			c->unchecked_size -= len;
827 			ref->flash_offset = ref_offset(ref) | REF_NORMAL;
828 			spin_unlock(&c->erase_completion_lock);
829 		}
830 	}
831 
832 	tn->fn = jffs2_alloc_full_dnode();
833 	if (!tn->fn) {
834 		JFFS2_ERROR("alloc fn failed\n");
835 		ret = -ENOMEM;
836 		goto free_out;
837 	}
838 
839 	tn->version = je32_to_cpu(rd->version);
840 	tn->fn->ofs = je32_to_cpu(rd->offset);
841 	tn->data_crc = je32_to_cpu(rd->data_crc);
842 	tn->csize = csize;
843 	tn->fn->raw = ref;
844 	tn->overlapped = 0;
845 
846 	if (tn->version > rii->highest_version)
847 		rii->highest_version = tn->version;
848 
849 	/* There was a bug where we wrote hole nodes out with
850 	   csize/dsize swapped. Deal with it */
851 	if (rd->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(rd->dsize) && csize)
852 		tn->fn->size = csize;
853 	else // normal case...
854 		tn->fn->size = je32_to_cpu(rd->dsize);
855 
856 	dbg_readinode2("dnode @%08x: ver %u, offset %#04x, dsize %#04x, csize %#04x\n",
857 		       ref_offset(ref), je32_to_cpu(rd->version),
858 		       je32_to_cpu(rd->offset), je32_to_cpu(rd->dsize), csize);
859 
860 	ret = jffs2_add_tn_to_tree(c, rii, tn);
861 
862 	if (ret) {
863 		jffs2_free_full_dnode(tn->fn);
864 	free_out:
865 		jffs2_free_tmp_dnode_info(tn);
866 		return ret;
867 	}
868 #ifdef JFFS2_DBG_READINODE2_MESSAGES
869 	dbg_readinode2("After adding ver %d:\n", je32_to_cpu(rd->version));
870 	tn = tn_first(&rii->tn_root);
871 	while (tn) {
872 		dbg_readinode2("%p: v %d r 0x%x-0x%x ov %d\n",
873 			       tn, tn->version, tn->fn->ofs,
874 			       tn->fn->ofs+tn->fn->size, tn->overlapped);
875 		tn = tn_next(tn);
876 	}
877 #endif
878 	return 0;
879 }
880 
881 /*
882  * Helper function for jffs2_get_inode_nodes().
883  * It is called every time an unknown node is found.
884  *
885  * Returns: 0 on success;
886  * 	    negative error code on failure.
887  */
read_unknown(struct jffs2_sb_info * c,struct jffs2_raw_node_ref * ref,struct jffs2_unknown_node * un)888 static inline int read_unknown(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref, struct jffs2_unknown_node *un)
889 {
890 	/* We don't mark unknown nodes as REF_UNCHECKED */
891 	if (ref_flags(ref) == REF_UNCHECKED) {
892 		JFFS2_ERROR("REF_UNCHECKED but unknown node at %#08x\n",
893 			    ref_offset(ref));
894 		JFFS2_ERROR("Node is {%04x,%04x,%08x,%08x}. Please report this error.\n",
895 			    je16_to_cpu(un->magic), je16_to_cpu(un->nodetype),
896 			    je32_to_cpu(un->totlen), je32_to_cpu(un->hdr_crc));
897 		jffs2_mark_node_obsolete(c, ref);
898 		return 0;
899 	}
900 
901 	un->nodetype = cpu_to_je16(JFFS2_NODE_ACCURATE | je16_to_cpu(un->nodetype));
902 
903 	switch(je16_to_cpu(un->nodetype) & JFFS2_COMPAT_MASK) {
904 
905 	case JFFS2_FEATURE_INCOMPAT:
906 		JFFS2_ERROR("unknown INCOMPAT nodetype %#04X at %#08x\n",
907 			    je16_to_cpu(un->nodetype), ref_offset(ref));
908 		/* EEP */
909 		BUG();
910 		break;
911 
912 	case JFFS2_FEATURE_ROCOMPAT:
913 		JFFS2_ERROR("unknown ROCOMPAT nodetype %#04X at %#08x\n",
914 			    je16_to_cpu(un->nodetype), ref_offset(ref));
915 		BUG_ON(!(c->flags & JFFS2_SB_FLAG_RO));
916 		break;
917 
918 	case JFFS2_FEATURE_RWCOMPAT_COPY:
919 		JFFS2_NOTICE("unknown RWCOMPAT_COPY nodetype %#04X at %#08x\n",
920 			     je16_to_cpu(un->nodetype), ref_offset(ref));
921 		break;
922 
923 	case JFFS2_FEATURE_RWCOMPAT_DELETE:
924 		JFFS2_NOTICE("unknown RWCOMPAT_DELETE nodetype %#04X at %#08x\n",
925 			     je16_to_cpu(un->nodetype), ref_offset(ref));
926 		jffs2_mark_node_obsolete(c, ref);
927 		return 0;
928 	}
929 
930 	return 0;
931 }
932 
933 /*
934  * Helper function for jffs2_get_inode_nodes().
935  * The function detects whether more data should be read and reads it if yes.
936  *
937  * Returns: 0 on success;
938  * 	    negative error code on failure.
939  */
read_more(struct jffs2_sb_info * c,struct jffs2_raw_node_ref * ref,int needed_len,int * rdlen,unsigned char * buf)940 static int read_more(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
941 		     int needed_len, int *rdlen, unsigned char *buf)
942 {
943 	int err, to_read = needed_len - *rdlen;
944 	size_t retlen;
945 	uint32_t offs;
946 
947 	if (jffs2_is_writebuffered(c)) {
948 		int rem = to_read % c->wbuf_pagesize;
949 
950 		if (rem)
951 			to_read += c->wbuf_pagesize - rem;
952 	}
953 
954 	/* We need to read more data */
955 	offs = ref_offset(ref) + *rdlen;
956 
957 	dbg_readinode("read more %d bytes\n", to_read);
958 
959 	err = jffs2_flash_read(c, offs, to_read, &retlen, buf + *rdlen);
960 	if (err) {
961 		JFFS2_ERROR("can not read %d bytes from 0x%08x, "
962 			"error code: %d.\n", to_read, offs, err);
963 		return err;
964 	}
965 
966 	if (retlen < to_read) {
967 		JFFS2_ERROR("short read at %#08x: %zu instead of %d.\n",
968 				offs, retlen, to_read);
969 		return -EIO;
970 	}
971 
972 	*rdlen += to_read;
973 	return 0;
974 }
975 
976 /* Get tmp_dnode_info and full_dirent for all non-obsolete nodes associated
977    with this ino. Perform a preliminary ordering on data nodes, throwing away
978    those which are completely obsoleted by newer ones. The naïve approach we
979    use to take of just returning them _all_ in version order will cause us to
980    run out of memory in certain degenerate cases. */
jffs2_get_inode_nodes(struct jffs2_sb_info * c,struct jffs2_inode_info * f,struct jffs2_readinode_info * rii)981 static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
982 				 struct jffs2_readinode_info *rii)
983 {
984 	struct jffs2_raw_node_ref *ref, *valid_ref;
985 	unsigned char *buf = NULL;
986 	union jffs2_node_union *node;
987 	size_t retlen;
988 	int len, err;
989 
990 	rii->mctime_ver = 0;
991 
992 	dbg_readinode("ino #%u\n", f->inocache->ino);
993 
994 	/* FIXME: in case of NOR and available ->point() this
995 	 * needs to be fixed. */
996 	len = sizeof(union jffs2_node_union) + c->wbuf_pagesize;
997 	buf = kmalloc(len, GFP_KERNEL);
998 	if (!buf)
999 		return -ENOMEM;
1000 
1001 	spin_lock(&c->erase_completion_lock);
1002 	valid_ref = jffs2_first_valid_node(f->inocache->nodes);
1003 	if (!valid_ref && f->inocache->ino != 1)
1004 		JFFS2_WARNING("Eep. No valid nodes for ino #%u.\n", f->inocache->ino);
1005 	while (valid_ref) {
1006 		/* We can hold a pointer to a non-obsolete node without the spinlock,
1007 		   but _obsolete_ nodes may disappear at any time, if the block
1008 		   they're in gets erased. So if we mark 'ref' obsolete while we're
1009 		   not holding the lock, it can go away immediately. For that reason,
1010 		   we find the next valid node first, before processing 'ref'.
1011 		*/
1012 		ref = valid_ref;
1013 		valid_ref = jffs2_first_valid_node(ref->next_in_ino);
1014 		spin_unlock(&c->erase_completion_lock);
1015 
1016 		cond_resched();
1017 
1018 		/*
1019 		 * At this point we don't know the type of the node we're going
1020 		 * to read, so we do not know the size of its header. In order
1021 		 * to minimize the amount of flash IO we assume the header is
1022 		 * of size = JFFS2_MIN_NODE_HEADER.
1023 		 */
1024 		len = JFFS2_MIN_NODE_HEADER;
1025 		if (jffs2_is_writebuffered(c)) {
1026 			int end, rem;
1027 
1028 			/*
1029 			 * We are about to read JFFS2_MIN_NODE_HEADER bytes,
1030 			 * but this flash has some minimal I/O unit. It is
1031 			 * possible that we'll need to read more soon, so read
1032 			 * up to the next min. I/O unit, in order not to
1033 			 * re-read the same min. I/O unit twice.
1034 			 */
1035 			end = ref_offset(ref) + len;
1036 			rem = end % c->wbuf_pagesize;
1037 			if (rem)
1038 				end += c->wbuf_pagesize - rem;
1039 			len = end - ref_offset(ref);
1040 		}
1041 
1042 		dbg_readinode("read %d bytes at %#08x(%d).\n", len, ref_offset(ref), ref_flags(ref));
1043 
1044 		/* FIXME: point() */
1045 		err = jffs2_flash_read(c, ref_offset(ref), len, &retlen, buf);
1046 		if (err) {
1047 			JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ref_offset(ref), err);
1048 			goto free_out;
1049 		}
1050 
1051 		if (retlen < len) {
1052 			JFFS2_ERROR("short read at %#08x: %zu instead of %d.\n", ref_offset(ref), retlen, len);
1053 			err = -EIO;
1054 			goto free_out;
1055 		}
1056 
1057 		node = (union jffs2_node_union *)buf;
1058 
1059 		/* No need to mask in the valid bit; it shouldn't be invalid */
1060 		if (je32_to_cpu(node->u.hdr_crc) != crc32(0, node, sizeof(node->u)-4)) {
1061 			JFFS2_NOTICE("Node header CRC failed at %#08x. {%04x,%04x,%08x,%08x}\n",
1062 				     ref_offset(ref), je16_to_cpu(node->u.magic),
1063 				     je16_to_cpu(node->u.nodetype),
1064 				     je32_to_cpu(node->u.totlen),
1065 				     je32_to_cpu(node->u.hdr_crc));
1066 			jffs2_dbg_dump_node(c, ref_offset(ref));
1067 			jffs2_mark_node_obsolete(c, ref);
1068 			goto cont;
1069 		}
1070 		if (je16_to_cpu(node->u.magic) != JFFS2_MAGIC_BITMASK) {
1071 			/* Not a JFFS2 node, whinge and move on */
1072 			JFFS2_NOTICE("Wrong magic bitmask 0x%04x in node header at %#08x.\n",
1073 				     je16_to_cpu(node->u.magic), ref_offset(ref));
1074 			jffs2_mark_node_obsolete(c, ref);
1075 			goto cont;
1076 		}
1077 
1078 		switch (je16_to_cpu(node->u.nodetype)) {
1079 
1080 		case JFFS2_NODETYPE_DIRENT:
1081 
1082 			if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_dirent) &&
1083 			    len < sizeof(struct jffs2_raw_dirent)) {
1084 				err = read_more(c, ref, sizeof(struct jffs2_raw_dirent), &len, buf);
1085 				if (unlikely(err))
1086 					goto free_out;
1087 			}
1088 
1089 			err = read_direntry(c, ref, &node->d, retlen, rii);
1090 			if (unlikely(err))
1091 				goto free_out;
1092 
1093 			break;
1094 
1095 		case JFFS2_NODETYPE_INODE:
1096 
1097 			if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_inode) &&
1098 			    len < sizeof(struct jffs2_raw_inode)) {
1099 				err = read_more(c, ref, sizeof(struct jffs2_raw_inode), &len, buf);
1100 				if (unlikely(err))
1101 					goto free_out;
1102 			}
1103 
1104 			err = read_dnode(c, ref, &node->i, len, rii);
1105 			if (unlikely(err))
1106 				goto free_out;
1107 
1108 			break;
1109 
1110 		default:
1111 			if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_unknown_node) &&
1112 			    len < sizeof(struct jffs2_unknown_node)) {
1113 				err = read_more(c, ref, sizeof(struct jffs2_unknown_node), &len, buf);
1114 				if (unlikely(err))
1115 					goto free_out;
1116 			}
1117 
1118 			err = read_unknown(c, ref, &node->u);
1119 			if (unlikely(err))
1120 				goto free_out;
1121 
1122 		}
1123 	cont:
1124 		spin_lock(&c->erase_completion_lock);
1125 	}
1126 
1127 	spin_unlock(&c->erase_completion_lock);
1128 	kfree(buf);
1129 
1130 	f->highest_version = rii->highest_version;
1131 
1132 	dbg_readinode("nodes of inode #%u were read, the highest version is %u, latest_mctime %u, mctime_ver %u.\n",
1133 		      f->inocache->ino, rii->highest_version, rii->latest_mctime,
1134 		      rii->mctime_ver);
1135 	return 0;
1136 
1137  free_out:
1138 	jffs2_free_tmp_dnode_info_list(&rii->tn_root);
1139 	jffs2_free_full_dirent_list(rii->fds);
1140 	rii->fds = NULL;
1141 	kfree(buf);
1142 	return err;
1143 }
1144 
jffs2_do_read_inode_internal(struct jffs2_sb_info * c,struct jffs2_inode_info * f,struct jffs2_raw_inode * latest_node)1145 static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
1146 					struct jffs2_inode_info *f,
1147 					struct jffs2_raw_inode *latest_node)
1148 {
1149 	struct jffs2_readinode_info rii;
1150 	uint32_t crc, new_size;
1151 	size_t retlen;
1152 	int ret;
1153 
1154 	dbg_readinode("ino #%u pino/nlink is %d\n", f->inocache->ino,
1155 		      f->inocache->pino_nlink);
1156 
1157 	memset(&rii, 0, sizeof(rii));
1158 
1159 	/* Grab all nodes relevant to this ino */
1160 	ret = jffs2_get_inode_nodes(c, f, &rii);
1161 
1162 	if (ret) {
1163 		JFFS2_ERROR("cannot read nodes for ino %u, returned error is %d\n", f->inocache->ino, ret);
1164 		if (f->inocache->state == INO_STATE_READING)
1165 			jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1166 		return ret;
1167 	}
1168 
1169 	ret = jffs2_build_inode_fragtree(c, f, &rii);
1170 	if (ret) {
1171 		JFFS2_ERROR("Failed to build final fragtree for inode #%u: error %d\n",
1172 			    f->inocache->ino, ret);
1173 		if (f->inocache->state == INO_STATE_READING)
1174 			jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1175 		jffs2_free_tmp_dnode_info_list(&rii.tn_root);
1176 		/* FIXME: We could at least crc-check them all */
1177 		if (rii.mdata_tn) {
1178 			jffs2_free_full_dnode(rii.mdata_tn->fn);
1179 			jffs2_free_tmp_dnode_info(rii.mdata_tn);
1180 			rii.mdata_tn = NULL;
1181 		}
1182 		return ret;
1183 	}
1184 
1185 	if (rii.mdata_tn) {
1186 		if (rii.mdata_tn->fn->raw == rii.latest_ref) {
1187 			f->metadata = rii.mdata_tn->fn;
1188 			jffs2_free_tmp_dnode_info(rii.mdata_tn);
1189 		} else {
1190 			jffs2_kill_tn(c, rii.mdata_tn);
1191 		}
1192 		rii.mdata_tn = NULL;
1193 	}
1194 
1195 	f->dents = rii.fds;
1196 
1197 	jffs2_dbg_fragtree_paranoia_check_nolock(f);
1198 
1199 	if (unlikely(!rii.latest_ref)) {
1200 		/* No data nodes for this inode. */
1201 		if (f->inocache->ino != 1) {
1202 			JFFS2_WARNING("no data nodes found for ino #%u\n", f->inocache->ino);
1203 			if (!rii.fds) {
1204 				if (f->inocache->state == INO_STATE_READING)
1205 					jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1206 				return -EIO;
1207 			}
1208 			JFFS2_NOTICE("but it has children so we fake some modes for it\n");
1209 		}
1210 		latest_node->mode = cpu_to_jemode(S_IFDIR|S_IRUGO|S_IWUSR|S_IXUGO);
1211 		latest_node->version = cpu_to_je32(0);
1212 		latest_node->atime = latest_node->ctime = latest_node->mtime = cpu_to_je32(0);
1213 		latest_node->isize = cpu_to_je32(0);
1214 		latest_node->gid = cpu_to_je16(0);
1215 		latest_node->uid = cpu_to_je16(0);
1216 		if (f->inocache->state == INO_STATE_READING)
1217 			jffs2_set_inocache_state(c, f->inocache, INO_STATE_PRESENT);
1218 		return 0;
1219 	}
1220 
1221 	ret = jffs2_flash_read(c, ref_offset(rii.latest_ref), sizeof(*latest_node), &retlen, (void *)latest_node);
1222 	if (ret || retlen != sizeof(*latest_node)) {
1223 		JFFS2_ERROR("failed to read from flash: error %d, %zd of %zd bytes read\n",
1224 			ret, retlen, sizeof(*latest_node));
1225 		/* FIXME: If this fails, there seems to be a memory leak. Find it. */
1226 		return ret ? ret : -EIO;
1227 	}
1228 
1229 	crc = crc32(0, latest_node, sizeof(*latest_node)-8);
1230 	if (crc != je32_to_cpu(latest_node->node_crc)) {
1231 		JFFS2_ERROR("CRC failed for read_inode of inode %u at physical location 0x%x\n",
1232 			f->inocache->ino, ref_offset(rii.latest_ref));
1233 		return -EIO;
1234 	}
1235 
1236 	switch(jemode_to_cpu(latest_node->mode) & S_IFMT) {
1237 	case S_IFDIR:
1238 		if (rii.mctime_ver > je32_to_cpu(latest_node->version)) {
1239 			/* The times in the latest_node are actually older than
1240 			   mctime in the latest dirent. Cheat. */
1241 			latest_node->ctime = latest_node->mtime = cpu_to_je32(rii.latest_mctime);
1242 		}
1243 		break;
1244 
1245 
1246 	case S_IFREG:
1247 		/* If it was a regular file, truncate it to the latest node's isize */
1248 		new_size = jffs2_truncate_fragtree(c, &f->fragtree, je32_to_cpu(latest_node->isize));
1249 		if (new_size != je32_to_cpu(latest_node->isize)) {
1250 			JFFS2_WARNING("Truncating ino #%u to %d bytes failed because it only had %d bytes to start with!\n",
1251 				      f->inocache->ino, je32_to_cpu(latest_node->isize), new_size);
1252 			latest_node->isize = cpu_to_je32(new_size);
1253 		}
1254 		break;
1255 
1256 	case S_IFLNK:
1257 		/* Hack to work around broken isize in old symlink code.
1258 		   Remove this when dwmw2 comes to his senses and stops
1259 		   symlinks from being an entirely gratuitous special
1260 		   case. */
1261 		if (!je32_to_cpu(latest_node->isize))
1262 			latest_node->isize = latest_node->dsize;
1263 
1264 		if (f->inocache->state != INO_STATE_CHECKING) {
1265 			/* Symlink's inode data is the target path. Read it and
1266 			 * keep in RAM to facilitate quick follow symlink
1267 			 * operation. */
1268 			uint32_t csize = je32_to_cpu(latest_node->csize);
1269 			if (csize > JFFS2_MAX_NAME_LEN)
1270 				return -ENAMETOOLONG;
1271 			f->target = kmalloc(csize + 1, GFP_KERNEL);
1272 			if (!f->target) {
1273 				JFFS2_ERROR("can't allocate %u bytes of memory for the symlink target path cache\n", csize);
1274 				return -ENOMEM;
1275 			}
1276 
1277 			ret = jffs2_flash_read(c, ref_offset(rii.latest_ref) + sizeof(*latest_node),
1278 					       csize, &retlen, (char *)f->target);
1279 
1280 			if (ret || retlen != csize) {
1281 				if (retlen != csize)
1282 					ret = -EIO;
1283 				kfree(f->target);
1284 				f->target = NULL;
1285 				return ret;
1286 			}
1287 
1288 			f->target[csize] = '\0';
1289 			dbg_readinode("symlink's target '%s' cached\n", f->target);
1290 		}
1291 
1292 		fallthrough;
1293 
1294 	case S_IFBLK:
1295 	case S_IFCHR:
1296 		/* Certain inode types should have only one data node, and it's
1297 		   kept as the metadata node */
1298 		if (f->metadata) {
1299 			JFFS2_ERROR("Argh. Special inode #%u with mode 0%o had metadata node\n",
1300 			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
1301 			return -EIO;
1302 		}
1303 		if (!frag_first(&f->fragtree)) {
1304 			JFFS2_ERROR("Argh. Special inode #%u with mode 0%o has no fragments\n",
1305 			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
1306 			return -EIO;
1307 		}
1308 		/* ASSERT: f->fraglist != NULL */
1309 		if (frag_next(frag_first(&f->fragtree))) {
1310 			JFFS2_ERROR("Argh. Special inode #%u with mode 0x%x had more than one node\n",
1311 			       f->inocache->ino, jemode_to_cpu(latest_node->mode));
1312 			/* FIXME: Deal with it - check crc32, check for duplicate node, check times and discard the older one */
1313 			return -EIO;
1314 		}
1315 		/* OK. We're happy */
1316 		f->metadata = frag_first(&f->fragtree)->node;
1317 		jffs2_free_node_frag(frag_first(&f->fragtree));
1318 		f->fragtree = RB_ROOT;
1319 		break;
1320 	}
1321 	if (f->inocache->state == INO_STATE_READING)
1322 		jffs2_set_inocache_state(c, f->inocache, INO_STATE_PRESENT);
1323 
1324 	return 0;
1325 }
1326 
1327 /* Scan the list of all nodes present for this ino, build map of versions, etc. */
jffs2_do_read_inode(struct jffs2_sb_info * c,struct jffs2_inode_info * f,uint32_t ino,struct jffs2_raw_inode * latest_node)1328 int jffs2_do_read_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
1329 			uint32_t ino, struct jffs2_raw_inode *latest_node)
1330 {
1331 	dbg_readinode("read inode #%u\n", ino);
1332 
1333  retry_inocache:
1334 	spin_lock(&c->inocache_lock);
1335 	f->inocache = jffs2_get_ino_cache(c, ino);
1336 
1337 	if (f->inocache) {
1338 		/* Check its state. We may need to wait before we can use it */
1339 		switch(f->inocache->state) {
1340 		case INO_STATE_UNCHECKED:
1341 		case INO_STATE_CHECKEDABSENT:
1342 			f->inocache->state = INO_STATE_READING;
1343 			break;
1344 
1345 		case INO_STATE_CHECKING:
1346 		case INO_STATE_GC:
1347 			/* If it's in either of these states, we need
1348 			   to wait for whoever's got it to finish and
1349 			   put it back. */
1350 			dbg_readinode("waiting for ino #%u in state %d\n", ino, f->inocache->state);
1351 			sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
1352 			goto retry_inocache;
1353 
1354 		case INO_STATE_READING:
1355 		case INO_STATE_PRESENT:
1356 			/* Eep. This should never happen. It can
1357 			happen if Linux calls read_inode() again
1358 			before clear_inode() has finished though. */
1359 			JFFS2_ERROR("Eep. Trying to read_inode #%u when it's already in state %d!\n", ino, f->inocache->state);
1360 			/* Fail. That's probably better than allowing it to succeed */
1361 			f->inocache = NULL;
1362 			break;
1363 
1364 		default:
1365 			BUG();
1366 		}
1367 	}
1368 	spin_unlock(&c->inocache_lock);
1369 
1370 	if (!f->inocache && ino == 1) {
1371 		/* Special case - no root inode on medium */
1372 		f->inocache = jffs2_alloc_inode_cache();
1373 		if (!f->inocache) {
1374 			JFFS2_ERROR("cannot allocate inocache for root inode\n");
1375 			return -ENOMEM;
1376 		}
1377 		dbg_readinode("creating inocache for root inode\n");
1378 		memset(f->inocache, 0, sizeof(struct jffs2_inode_cache));
1379 		f->inocache->ino = f->inocache->pino_nlink = 1;
1380 		f->inocache->nodes = (struct jffs2_raw_node_ref *)f->inocache;
1381 		f->inocache->state = INO_STATE_READING;
1382 		jffs2_add_ino_cache(c, f->inocache);
1383 	}
1384 	if (!f->inocache) {
1385 		JFFS2_ERROR("requested to read a nonexistent ino %u\n", ino);
1386 		return -ENOENT;
1387 	}
1388 
1389 	return jffs2_do_read_inode_internal(c, f, latest_node);
1390 }
1391 
jffs2_do_crccheck_inode(struct jffs2_sb_info * c,struct jffs2_inode_cache * ic)1392 int jffs2_do_crccheck_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
1393 {
1394 	struct jffs2_raw_inode n;
1395 	struct jffs2_inode_info *f = kzalloc(sizeof(*f), GFP_KERNEL);
1396 	int ret;
1397 
1398 	if (!f)
1399 		return -ENOMEM;
1400 
1401 	mutex_init(&f->sem);
1402 	mutex_lock(&f->sem);
1403 	f->inocache = ic;
1404 
1405 	ret = jffs2_do_read_inode_internal(c, f, &n);
1406 	mutex_unlock(&f->sem);
1407 	jffs2_do_clear_inode(c, f);
1408 	jffs2_xattr_do_crccheck_inode(c, ic);
1409 	kfree (f);
1410 	return ret;
1411 }
1412 
jffs2_do_clear_inode(struct jffs2_sb_info * c,struct jffs2_inode_info * f)1413 void jffs2_do_clear_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f)
1414 {
1415 	struct jffs2_full_dirent *fd, *fds;
1416 	int deleted;
1417 
1418 	jffs2_xattr_delete_inode(c, f->inocache);
1419 	mutex_lock(&f->sem);
1420 	deleted = f->inocache && !f->inocache->pino_nlink;
1421 
1422 	if (f->inocache && f->inocache->state != INO_STATE_CHECKING)
1423 		jffs2_set_inocache_state(c, f->inocache, INO_STATE_CLEARING);
1424 
1425 	if (f->metadata) {
1426 		if (deleted)
1427 			jffs2_mark_node_obsolete(c, f->metadata->raw);
1428 		jffs2_free_full_dnode(f->metadata);
1429 	}
1430 
1431 	jffs2_kill_fragtree(&f->fragtree, deleted?c:NULL);
1432 
1433 	fds = f->dents;
1434 	while(fds) {
1435 		fd = fds;
1436 		fds = fd->next;
1437 		jffs2_free_full_dirent(fd);
1438 	}
1439 
1440 	if (f->inocache && f->inocache->state != INO_STATE_CHECKING) {
1441 		jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1442 		if (f->inocache->nodes == (void *)f->inocache)
1443 			jffs2_del_ino_cache(c, f->inocache);
1444 	}
1445 
1446 	mutex_unlock(&f->sem);
1447 }
1448