xref: /openbmc/linux/drivers/mtd/ubi/attach.c (revision 025a06c1)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) International Business Machines Corp., 2006
4  *
5  * Author: Artem Bityutskiy (Битюцкий Артём)
6  */
7 
8 /*
9  * UBI attaching sub-system.
10  *
11  * This sub-system is responsible for attaching MTD devices and it also
12  * implements flash media scanning.
13  *
14  * The attaching information is represented by a &struct ubi_attach_info'
15  * object. Information about volumes is represented by &struct ubi_ainf_volume
16  * objects which are kept in volume RB-tree with root at the @volumes field.
17  * The RB-tree is indexed by the volume ID.
18  *
19  * Logical eraseblocks are represented by &struct ubi_ainf_peb objects. These
20  * objects are kept in per-volume RB-trees with the root at the corresponding
21  * &struct ubi_ainf_volume object. To put it differently, we keep an RB-tree of
22  * per-volume objects and each of these objects is the root of RB-tree of
23  * per-LEB objects.
24  *
25  * Corrupted physical eraseblocks are put to the @corr list, free physical
26  * eraseblocks are put to the @free list and the physical eraseblock to be
27  * erased are put to the @erase list.
28  *
29  * About corruptions
30  * ~~~~~~~~~~~~~~~~~
31  *
32  * UBI protects EC and VID headers with CRC-32 checksums, so it can detect
33  * whether the headers are corrupted or not. Sometimes UBI also protects the
34  * data with CRC-32, e.g., when it executes the atomic LEB change operation, or
35  * when it moves the contents of a PEB for wear-leveling purposes.
36  *
37  * UBI tries to distinguish between 2 types of corruptions.
38  *
39  * 1. Corruptions caused by power cuts. These are expected corruptions and UBI
40  * tries to handle them gracefully, without printing too many warnings and
41  * error messages. The idea is that we do not lose important data in these
42  * cases - we may lose only the data which were being written to the media just
43  * before the power cut happened, and the upper layers (e.g., UBIFS) are
44  * supposed to handle such data losses (e.g., by using the FS journal).
45  *
46  * When UBI detects a corruption (CRC-32 mismatch) in a PEB, and it looks like
47  * the reason is a power cut, UBI puts this PEB to the @erase list, and all
48  * PEBs in the @erase list are scheduled for erasure later.
49  *
50  * 2. Unexpected corruptions which are not caused by power cuts. During
51  * attaching, such PEBs are put to the @corr list and UBI preserves them.
52  * Obviously, this lessens the amount of available PEBs, and if at some  point
53  * UBI runs out of free PEBs, it switches to R/O mode. UBI also loudly informs
54  * about such PEBs every time the MTD device is attached.
55  *
56  * However, it is difficult to reliably distinguish between these types of
57  * corruptions and UBI's strategy is as follows (in case of attaching by
58  * scanning). UBI assumes corruption type 2 if the VID header is corrupted and
59  * the data area does not contain all 0xFFs, and there were no bit-flips or
60  * integrity errors (e.g., ECC errors in case of NAND) while reading the data
61  * area.  Otherwise UBI assumes corruption type 1. So the decision criteria
62  * are as follows.
63  *   o If the data area contains only 0xFFs, there are no data, and it is safe
64  *     to just erase this PEB - this is corruption type 1.
65  *   o If the data area has bit-flips or data integrity errors (ECC errors on
66  *     NAND), it is probably a PEB which was being erased when power cut
67  *     happened, so this is corruption type 1. However, this is just a guess,
68  *     which might be wrong.
69  *   o Otherwise this is corruption type 2.
70  */
71 
72 #include <linux/err.h>
73 #include <linux/slab.h>
74 #include <linux/crc32.h>
75 #include <linux/math64.h>
76 #include <linux/random.h>
77 #include "ubi.h"
78 
79 static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai);
80 
81 #define AV_FIND		BIT(0)
82 #define AV_ADD		BIT(1)
83 #define AV_FIND_OR_ADD	(AV_FIND | AV_ADD)
84 
85 /**
86  * find_or_add_av - internal function to find a volume, add a volume or do
87  *		    both (find and add if missing).
88  * @ai: attaching information
89  * @vol_id: the requested volume ID
90  * @flags: a combination of the %AV_FIND and %AV_ADD flags describing the
91  *	   expected operation. If only %AV_ADD is set, -EEXIST is returned
92  *	   if the volume already exists. If only %AV_FIND is set, NULL is
93  *	   returned if the volume does not exist. And if both flags are
94  *	   set, the helper first tries to find an existing volume, and if
95  *	   it does not exist it creates a new one.
96  * @created: in value used to inform the caller whether it"s a newly created
97  *	     volume or not.
98  *
99  * This function returns a pointer to a volume description or an ERR_PTR if
100  * the operation failed. It can also return NULL if only %AV_FIND is set and
101  * the volume does not exist.
102  */
find_or_add_av(struct ubi_attach_info * ai,int vol_id,unsigned int flags,bool * created)103 static struct ubi_ainf_volume *find_or_add_av(struct ubi_attach_info *ai,
104 					      int vol_id, unsigned int flags,
105 					      bool *created)
106 {
107 	struct ubi_ainf_volume *av;
108 	struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
109 
110 	/* Walk the volume RB-tree to look if this volume is already present */
111 	while (*p) {
112 		parent = *p;
113 		av = rb_entry(parent, struct ubi_ainf_volume, rb);
114 
115 		if (vol_id == av->vol_id) {
116 			*created = false;
117 
118 			if (!(flags & AV_FIND))
119 				return ERR_PTR(-EEXIST);
120 
121 			return av;
122 		}
123 
124 		if (vol_id > av->vol_id)
125 			p = &(*p)->rb_left;
126 		else
127 			p = &(*p)->rb_right;
128 	}
129 
130 	if (!(flags & AV_ADD))
131 		return NULL;
132 
133 	/* The volume is absent - add it */
134 	av = kzalloc(sizeof(*av), GFP_KERNEL);
135 	if (!av)
136 		return ERR_PTR(-ENOMEM);
137 
138 	av->vol_id = vol_id;
139 
140 	if (vol_id > ai->highest_vol_id)
141 		ai->highest_vol_id = vol_id;
142 
143 	rb_link_node(&av->rb, parent, p);
144 	rb_insert_color(&av->rb, &ai->volumes);
145 	ai->vols_found += 1;
146 	*created = true;
147 	dbg_bld("added volume %d", vol_id);
148 	return av;
149 }
150 
151 /**
152  * ubi_find_or_add_av - search for a volume in the attaching information and
153  *			add one if it does not exist.
154  * @ai: attaching information
155  * @vol_id: the requested volume ID
156  * @created: whether the volume has been created or not
157  *
158  * This function returns a pointer to the new volume description or an
159  * ERR_PTR if the operation failed.
160  */
ubi_find_or_add_av(struct ubi_attach_info * ai,int vol_id,bool * created)161 static struct ubi_ainf_volume *ubi_find_or_add_av(struct ubi_attach_info *ai,
162 						  int vol_id, bool *created)
163 {
164 	return find_or_add_av(ai, vol_id, AV_FIND_OR_ADD, created);
165 }
166 
167 /**
168  * ubi_alloc_aeb - allocate an aeb element
169  * @ai: attaching information
170  * @pnum: physical eraseblock number
171  * @ec: erase counter of the physical eraseblock
172  *
173  * Allocate an aeb object and initialize the pnum and ec information.
174  * vol_id and lnum are set to UBI_UNKNOWN, and the other fields are
175  * initialized to zero.
176  * Note that the element is not added in any list or RB tree.
177  */
ubi_alloc_aeb(struct ubi_attach_info * ai,int pnum,int ec)178 struct ubi_ainf_peb *ubi_alloc_aeb(struct ubi_attach_info *ai, int pnum,
179 				   int ec)
180 {
181 	struct ubi_ainf_peb *aeb;
182 
183 	aeb = kmem_cache_zalloc(ai->aeb_slab_cache, GFP_KERNEL);
184 	if (!aeb)
185 		return NULL;
186 
187 	aeb->pnum = pnum;
188 	aeb->ec = ec;
189 	aeb->vol_id = UBI_UNKNOWN;
190 	aeb->lnum = UBI_UNKNOWN;
191 
192 	return aeb;
193 }
194 
195 /**
196  * ubi_free_aeb - free an aeb element
197  * @ai: attaching information
198  * @aeb: the element to free
199  *
200  * Free an aeb object. The caller must have removed the element from any list
201  * or RB tree.
202  */
ubi_free_aeb(struct ubi_attach_info * ai,struct ubi_ainf_peb * aeb)203 void ubi_free_aeb(struct ubi_attach_info *ai, struct ubi_ainf_peb *aeb)
204 {
205 	kmem_cache_free(ai->aeb_slab_cache, aeb);
206 }
207 
208 /**
209  * add_to_list - add physical eraseblock to a list.
210  * @ai: attaching information
211  * @pnum: physical eraseblock number to add
212  * @vol_id: the last used volume id for the PEB
213  * @lnum: the last used LEB number for the PEB
214  * @ec: erase counter of the physical eraseblock
215  * @to_head: if not zero, add to the head of the list
216  * @list: the list to add to
217  *
218  * This function allocates a 'struct ubi_ainf_peb' object for physical
219  * eraseblock @pnum and adds it to the "free", "erase", or "alien" lists.
220  * It stores the @lnum and @vol_id alongside, which can both be
221  * %UBI_UNKNOWN if they are not available, not readable, or not assigned.
222  * If @to_head is not zero, PEB will be added to the head of the list, which
223  * basically means it will be processed first later. E.g., we add corrupted
224  * PEBs (corrupted due to power cuts) to the head of the erase list to make
225  * sure we erase them first and get rid of corruptions ASAP. This function
226  * returns zero in case of success and a negative error code in case of
227  * failure.
228  */
add_to_list(struct ubi_attach_info * ai,int pnum,int vol_id,int lnum,int ec,int to_head,struct list_head * list)229 static int add_to_list(struct ubi_attach_info *ai, int pnum, int vol_id,
230 		       int lnum, int ec, int to_head, struct list_head *list)
231 {
232 	struct ubi_ainf_peb *aeb;
233 
234 	if (list == &ai->free) {
235 		dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
236 	} else if (list == &ai->erase) {
237 		dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
238 	} else if (list == &ai->alien) {
239 		dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
240 		ai->alien_peb_count += 1;
241 	} else
242 		BUG();
243 
244 	aeb = ubi_alloc_aeb(ai, pnum, ec);
245 	if (!aeb)
246 		return -ENOMEM;
247 
248 	aeb->vol_id = vol_id;
249 	aeb->lnum = lnum;
250 	if (to_head)
251 		list_add(&aeb->u.list, list);
252 	else
253 		list_add_tail(&aeb->u.list, list);
254 	return 0;
255 }
256 
257 /**
258  * add_corrupted - add a corrupted physical eraseblock.
259  * @ai: attaching information
260  * @pnum: physical eraseblock number to add
261  * @ec: erase counter of the physical eraseblock
262  *
263  * This function allocates a 'struct ubi_ainf_peb' object for a corrupted
264  * physical eraseblock @pnum and adds it to the 'corr' list.  The corruption
265  * was presumably not caused by a power cut. Returns zero in case of success
266  * and a negative error code in case of failure.
267  */
add_corrupted(struct ubi_attach_info * ai,int pnum,int ec)268 static int add_corrupted(struct ubi_attach_info *ai, int pnum, int ec)
269 {
270 	struct ubi_ainf_peb *aeb;
271 
272 	dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
273 
274 	aeb = ubi_alloc_aeb(ai, pnum, ec);
275 	if (!aeb)
276 		return -ENOMEM;
277 
278 	ai->corr_peb_count += 1;
279 	list_add(&aeb->u.list, &ai->corr);
280 	return 0;
281 }
282 
283 /**
284  * add_fastmap - add a Fastmap related physical eraseblock.
285  * @ai: attaching information
286  * @pnum: physical eraseblock number the VID header came from
287  * @vid_hdr: the volume identifier header
288  * @ec: erase counter of the physical eraseblock
289  *
290  * This function allocates a 'struct ubi_ainf_peb' object for a Fastamp
291  * physical eraseblock @pnum and adds it to the 'fastmap' list.
292  * Such blocks can be Fastmap super and data blocks from both the most
293  * recent Fastmap we're attaching from or from old Fastmaps which will
294  * be erased.
295  */
add_fastmap(struct ubi_attach_info * ai,int pnum,struct ubi_vid_hdr * vid_hdr,int ec)296 static int add_fastmap(struct ubi_attach_info *ai, int pnum,
297 		       struct ubi_vid_hdr *vid_hdr, int ec)
298 {
299 	struct ubi_ainf_peb *aeb;
300 
301 	aeb = ubi_alloc_aeb(ai, pnum, ec);
302 	if (!aeb)
303 		return -ENOMEM;
304 
305 	aeb->vol_id = be32_to_cpu(vid_hdr->vol_id);
306 	aeb->sqnum = be64_to_cpu(vid_hdr->sqnum);
307 	list_add(&aeb->u.list, &ai->fastmap);
308 
309 	dbg_bld("add to fastmap list: PEB %d, vol_id %d, sqnum: %llu", pnum,
310 		aeb->vol_id, aeb->sqnum);
311 
312 	return 0;
313 }
314 
315 /**
316  * validate_vid_hdr - check volume identifier header.
317  * @ubi: UBI device description object
318  * @vid_hdr: the volume identifier header to check
319  * @av: information about the volume this logical eraseblock belongs to
320  * @pnum: physical eraseblock number the VID header came from
321  *
322  * This function checks that data stored in @vid_hdr is consistent. Returns
323  * non-zero if an inconsistency was found and zero if not.
324  *
325  * Note, UBI does sanity check of everything it reads from the flash media.
326  * Most of the checks are done in the I/O sub-system. Here we check that the
327  * information in the VID header is consistent to the information in other VID
328  * headers of the same volume.
329  */
validate_vid_hdr(const struct ubi_device * ubi,const struct ubi_vid_hdr * vid_hdr,const struct ubi_ainf_volume * av,int pnum)330 static int validate_vid_hdr(const struct ubi_device *ubi,
331 			    const struct ubi_vid_hdr *vid_hdr,
332 			    const struct ubi_ainf_volume *av, int pnum)
333 {
334 	int vol_type = vid_hdr->vol_type;
335 	int vol_id = be32_to_cpu(vid_hdr->vol_id);
336 	int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
337 	int data_pad = be32_to_cpu(vid_hdr->data_pad);
338 
339 	if (av->leb_count != 0) {
340 		int av_vol_type;
341 
342 		/*
343 		 * This is not the first logical eraseblock belonging to this
344 		 * volume. Ensure that the data in its VID header is consistent
345 		 * to the data in previous logical eraseblock headers.
346 		 */
347 
348 		if (vol_id != av->vol_id) {
349 			ubi_err(ubi, "inconsistent vol_id");
350 			goto bad;
351 		}
352 
353 		if (av->vol_type == UBI_STATIC_VOLUME)
354 			av_vol_type = UBI_VID_STATIC;
355 		else
356 			av_vol_type = UBI_VID_DYNAMIC;
357 
358 		if (vol_type != av_vol_type) {
359 			ubi_err(ubi, "inconsistent vol_type");
360 			goto bad;
361 		}
362 
363 		if (used_ebs != av->used_ebs) {
364 			ubi_err(ubi, "inconsistent used_ebs");
365 			goto bad;
366 		}
367 
368 		if (data_pad != av->data_pad) {
369 			ubi_err(ubi, "inconsistent data_pad");
370 			goto bad;
371 		}
372 	}
373 
374 	return 0;
375 
376 bad:
377 	ubi_err(ubi, "inconsistent VID header at PEB %d", pnum);
378 	ubi_dump_vid_hdr(vid_hdr);
379 	ubi_dump_av(av);
380 	return -EINVAL;
381 }
382 
383 /**
384  * add_volume - add volume to the attaching information.
385  * @ai: attaching information
386  * @vol_id: ID of the volume to add
387  * @pnum: physical eraseblock number
388  * @vid_hdr: volume identifier header
389  *
390  * If the volume corresponding to the @vid_hdr logical eraseblock is already
391  * present in the attaching information, this function does nothing. Otherwise
392  * it adds corresponding volume to the attaching information. Returns a pointer
393  * to the allocated "av" object in case of success and a negative error code in
394  * case of failure.
395  */
add_volume(struct ubi_attach_info * ai,int vol_id,int pnum,const struct ubi_vid_hdr * vid_hdr)396 static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai,
397 					  int vol_id, int pnum,
398 					  const struct ubi_vid_hdr *vid_hdr)
399 {
400 	struct ubi_ainf_volume *av;
401 	bool created;
402 
403 	ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
404 
405 	av = ubi_find_or_add_av(ai, vol_id, &created);
406 	if (IS_ERR(av) || !created)
407 		return av;
408 
409 	av->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
410 	av->data_pad = be32_to_cpu(vid_hdr->data_pad);
411 	av->compat = vid_hdr->compat;
412 	av->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
413 							    : UBI_STATIC_VOLUME;
414 
415 	return av;
416 }
417 
418 /**
419  * ubi_compare_lebs - find out which logical eraseblock is newer.
420  * @ubi: UBI device description object
421  * @aeb: first logical eraseblock to compare
422  * @pnum: physical eraseblock number of the second logical eraseblock to
423  * compare
424  * @vid_hdr: volume identifier header of the second logical eraseblock
425  *
426  * This function compares 2 copies of a LEB and informs which one is newer. In
427  * case of success this function returns a positive value, in case of failure, a
428  * negative error code is returned. The success return codes use the following
429  * bits:
430  *     o bit 0 is cleared: the first PEB (described by @aeb) is newer than the
431  *       second PEB (described by @pnum and @vid_hdr);
432  *     o bit 0 is set: the second PEB is newer;
433  *     o bit 1 is cleared: no bit-flips were detected in the newer LEB;
434  *     o bit 1 is set: bit-flips were detected in the newer LEB;
435  *     o bit 2 is cleared: the older LEB is not corrupted;
436  *     o bit 2 is set: the older LEB is corrupted.
437  */
ubi_compare_lebs(struct ubi_device * ubi,const struct ubi_ainf_peb * aeb,int pnum,const struct ubi_vid_hdr * vid_hdr)438 int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
439 			int pnum, const struct ubi_vid_hdr *vid_hdr)
440 {
441 	int len, err, second_is_newer, bitflips = 0, corrupted = 0;
442 	uint32_t data_crc, crc;
443 	struct ubi_vid_io_buf *vidb = NULL;
444 	unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
445 
446 	if (sqnum2 == aeb->sqnum) {
447 		/*
448 		 * This must be a really ancient UBI image which has been
449 		 * created before sequence numbers support has been added. At
450 		 * that times we used 32-bit LEB versions stored in logical
451 		 * eraseblocks. That was before UBI got into mainline. We do not
452 		 * support these images anymore. Well, those images still work,
453 		 * but only if no unclean reboots happened.
454 		 */
455 		ubi_err(ubi, "unsupported on-flash UBI format");
456 		return -EINVAL;
457 	}
458 
459 	/* Obviously the LEB with lower sequence counter is older */
460 	second_is_newer = (sqnum2 > aeb->sqnum);
461 
462 	/*
463 	 * Now we know which copy is newer. If the copy flag of the PEB with
464 	 * newer version is not set, then we just return, otherwise we have to
465 	 * check data CRC. For the second PEB we already have the VID header,
466 	 * for the first one - we'll need to re-read it from flash.
467 	 *
468 	 * Note: this may be optimized so that we wouldn't read twice.
469 	 */
470 
471 	if (second_is_newer) {
472 		if (!vid_hdr->copy_flag) {
473 			/* It is not a copy, so it is newer */
474 			dbg_bld("second PEB %d is newer, copy_flag is unset",
475 				pnum);
476 			return 1;
477 		}
478 	} else {
479 		if (!aeb->copy_flag) {
480 			/* It is not a copy, so it is newer */
481 			dbg_bld("first PEB %d is newer, copy_flag is unset",
482 				pnum);
483 			return bitflips << 1;
484 		}
485 
486 		vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
487 		if (!vidb)
488 			return -ENOMEM;
489 
490 		pnum = aeb->pnum;
491 		err = ubi_io_read_vid_hdr(ubi, pnum, vidb, 0);
492 		if (err) {
493 			if (err == UBI_IO_BITFLIPS)
494 				bitflips = 1;
495 			else {
496 				ubi_err(ubi, "VID of PEB %d header is bad, but it was OK earlier, err %d",
497 					pnum, err);
498 				if (err > 0)
499 					err = -EIO;
500 
501 				goto out_free_vidh;
502 			}
503 		}
504 
505 		vid_hdr = ubi_get_vid_hdr(vidb);
506 	}
507 
508 	/* Read the data of the copy and check the CRC */
509 
510 	len = be32_to_cpu(vid_hdr->data_size);
511 
512 	mutex_lock(&ubi->buf_mutex);
513 	err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, len);
514 	if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
515 		goto out_unlock;
516 
517 	data_crc = be32_to_cpu(vid_hdr->data_crc);
518 	crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, len);
519 	if (crc != data_crc) {
520 		dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
521 			pnum, crc, data_crc);
522 		corrupted = 1;
523 		bitflips = 0;
524 		second_is_newer = !second_is_newer;
525 	} else {
526 		dbg_bld("PEB %d CRC is OK", pnum);
527 		bitflips |= !!err;
528 	}
529 	mutex_unlock(&ubi->buf_mutex);
530 
531 	ubi_free_vid_buf(vidb);
532 
533 	if (second_is_newer)
534 		dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
535 	else
536 		dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
537 
538 	return second_is_newer | (bitflips << 1) | (corrupted << 2);
539 
540 out_unlock:
541 	mutex_unlock(&ubi->buf_mutex);
542 out_free_vidh:
543 	ubi_free_vid_buf(vidb);
544 	return err;
545 }
546 
547 /**
548  * ubi_add_to_av - add used physical eraseblock to the attaching information.
549  * @ubi: UBI device description object
550  * @ai: attaching information
551  * @pnum: the physical eraseblock number
552  * @ec: erase counter
553  * @vid_hdr: the volume identifier header
554  * @bitflips: if bit-flips were detected when this physical eraseblock was read
555  *
556  * This function adds information about a used physical eraseblock to the
557  * 'used' tree of the corresponding volume. The function is rather complex
558  * because it has to handle cases when this is not the first physical
559  * eraseblock belonging to the same logical eraseblock, and the newer one has
560  * to be picked, while the older one has to be dropped. This function returns
561  * zero in case of success and a negative error code in case of failure.
562  */
ubi_add_to_av(struct ubi_device * ubi,struct ubi_attach_info * ai,int pnum,int ec,const struct ubi_vid_hdr * vid_hdr,int bitflips)563 int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
564 		  int ec, const struct ubi_vid_hdr *vid_hdr, int bitflips)
565 {
566 	int err, vol_id, lnum;
567 	unsigned long long sqnum;
568 	struct ubi_ainf_volume *av;
569 	struct ubi_ainf_peb *aeb;
570 	struct rb_node **p, *parent = NULL;
571 
572 	vol_id = be32_to_cpu(vid_hdr->vol_id);
573 	lnum = be32_to_cpu(vid_hdr->lnum);
574 	sqnum = be64_to_cpu(vid_hdr->sqnum);
575 
576 	dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
577 		pnum, vol_id, lnum, ec, sqnum, bitflips);
578 
579 	av = add_volume(ai, vol_id, pnum, vid_hdr);
580 	if (IS_ERR(av))
581 		return PTR_ERR(av);
582 
583 	if (ai->max_sqnum < sqnum)
584 		ai->max_sqnum = sqnum;
585 
586 	/*
587 	 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
588 	 * if this is the first instance of this logical eraseblock or not.
589 	 */
590 	p = &av->root.rb_node;
591 	while (*p) {
592 		int cmp_res;
593 
594 		parent = *p;
595 		aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
596 		if (lnum != aeb->lnum) {
597 			if (lnum < aeb->lnum)
598 				p = &(*p)->rb_left;
599 			else
600 				p = &(*p)->rb_right;
601 			continue;
602 		}
603 
604 		/*
605 		 * There is already a physical eraseblock describing the same
606 		 * logical eraseblock present.
607 		 */
608 
609 		dbg_bld("this LEB already exists: PEB %d, sqnum %llu, EC %d",
610 			aeb->pnum, aeb->sqnum, aeb->ec);
611 
612 		/*
613 		 * Make sure that the logical eraseblocks have different
614 		 * sequence numbers. Otherwise the image is bad.
615 		 *
616 		 * However, if the sequence number is zero, we assume it must
617 		 * be an ancient UBI image from the era when UBI did not have
618 		 * sequence numbers. We still can attach these images, unless
619 		 * there is a need to distinguish between old and new
620 		 * eraseblocks, in which case we'll refuse the image in
621 		 * 'ubi_compare_lebs()'. In other words, we attach old clean
622 		 * images, but refuse attaching old images with duplicated
623 		 * logical eraseblocks because there was an unclean reboot.
624 		 */
625 		if (aeb->sqnum == sqnum && sqnum != 0) {
626 			ubi_err(ubi, "two LEBs with same sequence number %llu",
627 				sqnum);
628 			ubi_dump_aeb(aeb, 0);
629 			ubi_dump_vid_hdr(vid_hdr);
630 			return -EINVAL;
631 		}
632 
633 		/*
634 		 * Now we have to drop the older one and preserve the newer
635 		 * one.
636 		 */
637 		cmp_res = ubi_compare_lebs(ubi, aeb, pnum, vid_hdr);
638 		if (cmp_res < 0)
639 			return cmp_res;
640 
641 		if (cmp_res & 1) {
642 			/*
643 			 * This logical eraseblock is newer than the one
644 			 * found earlier.
645 			 */
646 			err = validate_vid_hdr(ubi, vid_hdr, av, pnum);
647 			if (err)
648 				return err;
649 
650 			err = add_to_list(ai, aeb->pnum, aeb->vol_id,
651 					  aeb->lnum, aeb->ec, cmp_res & 4,
652 					  &ai->erase);
653 			if (err)
654 				return err;
655 
656 			aeb->ec = ec;
657 			aeb->pnum = pnum;
658 			aeb->vol_id = vol_id;
659 			aeb->lnum = lnum;
660 			aeb->scrub = ((cmp_res & 2) || bitflips);
661 			aeb->copy_flag = vid_hdr->copy_flag;
662 			aeb->sqnum = sqnum;
663 
664 			if (av->highest_lnum == lnum)
665 				av->last_data_size =
666 					be32_to_cpu(vid_hdr->data_size);
667 
668 			return 0;
669 		} else {
670 			/*
671 			 * This logical eraseblock is older than the one found
672 			 * previously.
673 			 */
674 			return add_to_list(ai, pnum, vol_id, lnum, ec,
675 					   cmp_res & 4, &ai->erase);
676 		}
677 	}
678 
679 	/*
680 	 * We've met this logical eraseblock for the first time, add it to the
681 	 * attaching information.
682 	 */
683 
684 	err = validate_vid_hdr(ubi, vid_hdr, av, pnum);
685 	if (err)
686 		return err;
687 
688 	aeb = ubi_alloc_aeb(ai, pnum, ec);
689 	if (!aeb)
690 		return -ENOMEM;
691 
692 	aeb->vol_id = vol_id;
693 	aeb->lnum = lnum;
694 	aeb->scrub = bitflips;
695 	aeb->copy_flag = vid_hdr->copy_flag;
696 	aeb->sqnum = sqnum;
697 
698 	if (av->highest_lnum <= lnum) {
699 		av->highest_lnum = lnum;
700 		av->last_data_size = be32_to_cpu(vid_hdr->data_size);
701 	}
702 
703 	av->leb_count += 1;
704 	rb_link_node(&aeb->u.rb, parent, p);
705 	rb_insert_color(&aeb->u.rb, &av->root);
706 	return 0;
707 }
708 
709 /**
710  * ubi_add_av - add volume to the attaching information.
711  * @ai: attaching information
712  * @vol_id: the requested volume ID
713  *
714  * This function returns a pointer to the new volume description or an
715  * ERR_PTR if the operation failed.
716  */
ubi_add_av(struct ubi_attach_info * ai,int vol_id)717 struct ubi_ainf_volume *ubi_add_av(struct ubi_attach_info *ai, int vol_id)
718 {
719 	bool created;
720 
721 	return find_or_add_av(ai, vol_id, AV_ADD, &created);
722 }
723 
724 /**
725  * ubi_find_av - find volume in the attaching information.
726  * @ai: attaching information
727  * @vol_id: the requested volume ID
728  *
729  * This function returns a pointer to the volume description or %NULL if there
730  * are no data about this volume in the attaching information.
731  */
ubi_find_av(const struct ubi_attach_info * ai,int vol_id)732 struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai,
733 				    int vol_id)
734 {
735 	bool created;
736 
737 	return find_or_add_av((struct ubi_attach_info *)ai, vol_id, AV_FIND,
738 			      &created);
739 }
740 
741 static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av,
742 		       struct list_head *list);
743 
744 /**
745  * ubi_remove_av - delete attaching information about a volume.
746  * @ai: attaching information
747  * @av: the volume attaching information to delete
748  */
ubi_remove_av(struct ubi_attach_info * ai,struct ubi_ainf_volume * av)749 void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
750 {
751 	dbg_bld("remove attaching information about volume %d", av->vol_id);
752 
753 	rb_erase(&av->rb, &ai->volumes);
754 	destroy_av(ai, av, &ai->erase);
755 	ai->vols_found -= 1;
756 }
757 
758 /**
759  * early_erase_peb - erase a physical eraseblock.
760  * @ubi: UBI device description object
761  * @ai: attaching information
762  * @pnum: physical eraseblock number to erase;
763  * @ec: erase counter value to write (%UBI_UNKNOWN if it is unknown)
764  *
765  * This function erases physical eraseblock 'pnum', and writes the erase
766  * counter header to it. This function should only be used on UBI device
767  * initialization stages, when the EBA sub-system had not been yet initialized.
768  * This function returns zero in case of success and a negative error code in
769  * case of failure.
770  */
early_erase_peb(struct ubi_device * ubi,const struct ubi_attach_info * ai,int pnum,int ec)771 static int early_erase_peb(struct ubi_device *ubi,
772 			   const struct ubi_attach_info *ai, int pnum, int ec)
773 {
774 	int err;
775 	struct ubi_ec_hdr *ec_hdr;
776 
777 	if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
778 		/*
779 		 * Erase counter overflow. Upgrade UBI and use 64-bit
780 		 * erase counters internally.
781 		 */
782 		ubi_err(ubi, "erase counter overflow at PEB %d, EC %d",
783 			pnum, ec);
784 		return -EINVAL;
785 	}
786 
787 	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
788 	if (!ec_hdr)
789 		return -ENOMEM;
790 
791 	ec_hdr->ec = cpu_to_be64(ec);
792 
793 	err = ubi_io_sync_erase(ubi, pnum, 0);
794 	if (err < 0)
795 		goto out_free;
796 
797 	err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
798 
799 out_free:
800 	kfree(ec_hdr);
801 	return err;
802 }
803 
804 /**
805  * ubi_early_get_peb - get a free physical eraseblock.
806  * @ubi: UBI device description object
807  * @ai: attaching information
808  *
809  * This function returns a free physical eraseblock. It is supposed to be
810  * called on the UBI initialization stages when the wear-leveling sub-system is
811  * not initialized yet. This function picks a physical eraseblocks from one of
812  * the lists, writes the EC header if it is needed, and removes it from the
813  * list.
814  *
815  * This function returns a pointer to the "aeb" of the found free PEB in case
816  * of success and an error code in case of failure.
817  */
ubi_early_get_peb(struct ubi_device * ubi,struct ubi_attach_info * ai)818 struct ubi_ainf_peb *ubi_early_get_peb(struct ubi_device *ubi,
819 				       struct ubi_attach_info *ai)
820 {
821 	int err = 0;
822 	struct ubi_ainf_peb *aeb, *tmp_aeb;
823 
824 	if (!list_empty(&ai->free)) {
825 		aeb = list_entry(ai->free.next, struct ubi_ainf_peb, u.list);
826 		list_del(&aeb->u.list);
827 		dbg_bld("return free PEB %d, EC %d", aeb->pnum, aeb->ec);
828 		return aeb;
829 	}
830 
831 	/*
832 	 * We try to erase the first physical eraseblock from the erase list
833 	 * and pick it if we succeed, or try to erase the next one if not. And
834 	 * so forth. We don't want to take care about bad eraseblocks here -
835 	 * they'll be handled later.
836 	 */
837 	list_for_each_entry_safe(aeb, tmp_aeb, &ai->erase, u.list) {
838 		if (aeb->ec == UBI_UNKNOWN)
839 			aeb->ec = ai->mean_ec;
840 
841 		err = early_erase_peb(ubi, ai, aeb->pnum, aeb->ec+1);
842 		if (err)
843 			continue;
844 
845 		aeb->ec += 1;
846 		list_del(&aeb->u.list);
847 		dbg_bld("return PEB %d, EC %d", aeb->pnum, aeb->ec);
848 		return aeb;
849 	}
850 
851 	ubi_err(ubi, "no free eraseblocks");
852 	return ERR_PTR(-ENOSPC);
853 }
854 
855 /**
856  * check_corruption - check the data area of PEB.
857  * @ubi: UBI device description object
858  * @vid_hdr: the (corrupted) VID header of this PEB
859  * @pnum: the physical eraseblock number to check
860  *
861  * This is a helper function which is used to distinguish between VID header
862  * corruptions caused by power cuts and other reasons. If the PEB contains only
863  * 0xFF bytes in the data area, the VID header is most probably corrupted
864  * because of a power cut (%0 is returned in this case). Otherwise, it was
865  * probably corrupted for some other reasons (%1 is returned in this case). A
866  * negative error code is returned if a read error occurred.
867  *
868  * If the corruption reason was a power cut, UBI can safely erase this PEB.
869  * Otherwise, it should preserve it to avoid possibly destroying important
870  * information.
871  */
check_corruption(struct ubi_device * ubi,struct ubi_vid_hdr * vid_hdr,int pnum)872 static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr,
873 			    int pnum)
874 {
875 	int err;
876 
877 	mutex_lock(&ubi->buf_mutex);
878 	memset(ubi->peb_buf, 0x00, ubi->leb_size);
879 
880 	err = ubi_io_read(ubi, ubi->peb_buf, pnum, ubi->leb_start,
881 			  ubi->leb_size);
882 	if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
883 		/*
884 		 * Bit-flips or integrity errors while reading the data area.
885 		 * It is difficult to say for sure what type of corruption is
886 		 * this, but presumably a power cut happened while this PEB was
887 		 * erased, so it became unstable and corrupted, and should be
888 		 * erased.
889 		 */
890 		err = 0;
891 		goto out_unlock;
892 	}
893 
894 	if (err)
895 		goto out_unlock;
896 
897 	if (ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->leb_size))
898 		goto out_unlock;
899 
900 	ubi_err(ubi, "PEB %d contains corrupted VID header, and the data does not contain all 0xFF",
901 		pnum);
902 	ubi_err(ubi, "this may be a non-UBI PEB or a severe VID header corruption which requires manual inspection");
903 	ubi_dump_vid_hdr(vid_hdr);
904 	pr_err("hexdump of PEB %d offset %d, length %d",
905 	       pnum, ubi->leb_start, ubi->leb_size);
906 	ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
907 			       ubi->peb_buf, ubi->leb_size, 1);
908 	err = 1;
909 
910 out_unlock:
911 	mutex_unlock(&ubi->buf_mutex);
912 	return err;
913 }
914 
vol_ignored(int vol_id)915 static bool vol_ignored(int vol_id)
916 {
917 	switch (vol_id) {
918 		case UBI_LAYOUT_VOLUME_ID:
919 		return true;
920 	}
921 
922 #ifdef CONFIG_MTD_UBI_FASTMAP
923 	return ubi_is_fm_vol(vol_id);
924 #else
925 	return false;
926 #endif
927 }
928 
929 /**
930  * scan_peb - scan and process UBI headers of a PEB.
931  * @ubi: UBI device description object
932  * @ai: attaching information
933  * @pnum: the physical eraseblock number
934  * @fast: true if we're scanning for a Fastmap
935  *
936  * This function reads UBI headers of PEB @pnum, checks them, and adds
937  * information about this PEB to the corresponding list or RB-tree in the
938  * "attaching info" structure. Returns zero if the physical eraseblock was
939  * successfully handled and a negative error code in case of failure.
940  */
scan_peb(struct ubi_device * ubi,struct ubi_attach_info * ai,int pnum,bool fast)941 static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
942 		    int pnum, bool fast)
943 {
944 	struct ubi_ec_hdr *ech = ai->ech;
945 	struct ubi_vid_io_buf *vidb = ai->vidb;
946 	struct ubi_vid_hdr *vidh = ubi_get_vid_hdr(vidb);
947 	long long ec;
948 	int err, bitflips = 0, vol_id = -1, ec_err = 0;
949 
950 	dbg_bld("scan PEB %d", pnum);
951 
952 	/* Skip bad physical eraseblocks */
953 	err = ubi_io_is_bad(ubi, pnum);
954 	if (err < 0)
955 		return err;
956 	else if (err) {
957 		ai->bad_peb_count += 1;
958 		return 0;
959 	}
960 
961 	err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
962 	if (err < 0)
963 		return err;
964 	switch (err) {
965 	case 0:
966 		break;
967 	case UBI_IO_BITFLIPS:
968 		bitflips = 1;
969 		break;
970 	case UBI_IO_FF:
971 		ai->empty_peb_count += 1;
972 		return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
973 				   UBI_UNKNOWN, 0, &ai->erase);
974 	case UBI_IO_FF_BITFLIPS:
975 		ai->empty_peb_count += 1;
976 		return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
977 				   UBI_UNKNOWN, 1, &ai->erase);
978 	case UBI_IO_BAD_HDR_EBADMSG:
979 	case UBI_IO_BAD_HDR:
980 		/*
981 		 * We have to also look at the VID header, possibly it is not
982 		 * corrupted. Set %bitflips flag in order to make this PEB be
983 		 * moved and EC be re-created.
984 		 */
985 		ec_err = err;
986 		ec = UBI_UNKNOWN;
987 		bitflips = 1;
988 		break;
989 	default:
990 		ubi_err(ubi, "'ubi_io_read_ec_hdr()' returned unknown code %d",
991 			err);
992 		return -EINVAL;
993 	}
994 
995 	if (!ec_err) {
996 		int image_seq;
997 
998 		/* Make sure UBI version is OK */
999 		if (ech->version != UBI_VERSION) {
1000 			ubi_err(ubi, "this UBI version is %d, image version is %d",
1001 				UBI_VERSION, (int)ech->version);
1002 			return -EINVAL;
1003 		}
1004 
1005 		ec = be64_to_cpu(ech->ec);
1006 		if (ec > UBI_MAX_ERASECOUNTER) {
1007 			/*
1008 			 * Erase counter overflow. The EC headers have 64 bits
1009 			 * reserved, but we anyway make use of only 31 bit
1010 			 * values, as this seems to be enough for any existing
1011 			 * flash. Upgrade UBI and use 64-bit erase counters
1012 			 * internally.
1013 			 */
1014 			ubi_err(ubi, "erase counter overflow, max is %d",
1015 				UBI_MAX_ERASECOUNTER);
1016 			ubi_dump_ec_hdr(ech);
1017 			return -EINVAL;
1018 		}
1019 
1020 		/*
1021 		 * Make sure that all PEBs have the same image sequence number.
1022 		 * This allows us to detect situations when users flash UBI
1023 		 * images incorrectly, so that the flash has the new UBI image
1024 		 * and leftovers from the old one. This feature was added
1025 		 * relatively recently, and the sequence number was always
1026 		 * zero, because old UBI implementations always set it to zero.
1027 		 * For this reasons, we do not panic if some PEBs have zero
1028 		 * sequence number, while other PEBs have non-zero sequence
1029 		 * number.
1030 		 */
1031 		image_seq = be32_to_cpu(ech->image_seq);
1032 		if (!ubi->image_seq)
1033 			ubi->image_seq = image_seq;
1034 		if (image_seq && ubi->image_seq != image_seq) {
1035 			ubi_err(ubi, "bad image sequence number %d in PEB %d, expected %d",
1036 				image_seq, pnum, ubi->image_seq);
1037 			ubi_dump_ec_hdr(ech);
1038 			return -EINVAL;
1039 		}
1040 	}
1041 
1042 	/* OK, we've done with the EC header, let's look at the VID header */
1043 
1044 	err = ubi_io_read_vid_hdr(ubi, pnum, vidb, 0);
1045 	if (err < 0)
1046 		return err;
1047 	switch (err) {
1048 	case 0:
1049 		break;
1050 	case UBI_IO_BITFLIPS:
1051 		bitflips = 1;
1052 		break;
1053 	case UBI_IO_BAD_HDR_EBADMSG:
1054 		if (ec_err == UBI_IO_BAD_HDR_EBADMSG)
1055 			/*
1056 			 * Both EC and VID headers are corrupted and were read
1057 			 * with data integrity error, probably this is a bad
1058 			 * PEB, bit it is not marked as bad yet. This may also
1059 			 * be a result of power cut during erasure.
1060 			 */
1061 			ai->maybe_bad_peb_count += 1;
1062 		fallthrough;
1063 	case UBI_IO_BAD_HDR:
1064 			/*
1065 			 * If we're facing a bad VID header we have to drop *all*
1066 			 * Fastmap data structures we find. The most recent Fastmap
1067 			 * could be bad and therefore there is a chance that we attach
1068 			 * from an old one. On a fine MTD stack a PEB must not render
1069 			 * bad all of a sudden, but the reality is different.
1070 			 * So, let's be paranoid and help finding the root cause by
1071 			 * falling back to scanning mode instead of attaching with a
1072 			 * bad EBA table and cause data corruption which is hard to
1073 			 * analyze.
1074 			 */
1075 			if (fast)
1076 				ai->force_full_scan = 1;
1077 
1078 		if (ec_err)
1079 			/*
1080 			 * Both headers are corrupted. There is a possibility
1081 			 * that this a valid UBI PEB which has corresponding
1082 			 * LEB, but the headers are corrupted. However, it is
1083 			 * impossible to distinguish it from a PEB which just
1084 			 * contains garbage because of a power cut during erase
1085 			 * operation. So we just schedule this PEB for erasure.
1086 			 *
1087 			 * Besides, in case of NOR flash, we deliberately
1088 			 * corrupt both headers because NOR flash erasure is
1089 			 * slow and can start from the end.
1090 			 */
1091 			err = 0;
1092 		else
1093 			/*
1094 			 * The EC was OK, but the VID header is corrupted. We
1095 			 * have to check what is in the data area.
1096 			 */
1097 			err = check_corruption(ubi, vidh, pnum);
1098 
1099 		if (err < 0)
1100 			return err;
1101 		else if (!err)
1102 			/* This corruption is caused by a power cut */
1103 			err = add_to_list(ai, pnum, UBI_UNKNOWN,
1104 					  UBI_UNKNOWN, ec, 1, &ai->erase);
1105 		else
1106 			/* This is an unexpected corruption */
1107 			err = add_corrupted(ai, pnum, ec);
1108 		if (err)
1109 			return err;
1110 		goto adjust_mean_ec;
1111 	case UBI_IO_FF_BITFLIPS:
1112 		err = add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
1113 				  ec, 1, &ai->erase);
1114 		if (err)
1115 			return err;
1116 		goto adjust_mean_ec;
1117 	case UBI_IO_FF:
1118 		if (ec_err || bitflips)
1119 			err = add_to_list(ai, pnum, UBI_UNKNOWN,
1120 					  UBI_UNKNOWN, ec, 1, &ai->erase);
1121 		else
1122 			err = add_to_list(ai, pnum, UBI_UNKNOWN,
1123 					  UBI_UNKNOWN, ec, 0, &ai->free);
1124 		if (err)
1125 			return err;
1126 		goto adjust_mean_ec;
1127 	default:
1128 		ubi_err(ubi, "'ubi_io_read_vid_hdr()' returned unknown code %d",
1129 			err);
1130 		return -EINVAL;
1131 	}
1132 
1133 	vol_id = be32_to_cpu(vidh->vol_id);
1134 	if (vol_id > UBI_MAX_VOLUMES && !vol_ignored(vol_id)) {
1135 		int lnum = be32_to_cpu(vidh->lnum);
1136 
1137 		/* Unsupported internal volume */
1138 		switch (vidh->compat) {
1139 		case UBI_COMPAT_DELETE:
1140 			ubi_msg(ubi, "\"delete\" compatible internal volume %d:%d found, will remove it",
1141 				vol_id, lnum);
1142 
1143 			err = add_to_list(ai, pnum, vol_id, lnum,
1144 					  ec, 1, &ai->erase);
1145 			if (err)
1146 				return err;
1147 			return 0;
1148 
1149 		case UBI_COMPAT_RO:
1150 			ubi_msg(ubi, "read-only compatible internal volume %d:%d found, switch to read-only mode",
1151 				vol_id, lnum);
1152 			ubi->ro_mode = 1;
1153 			break;
1154 
1155 		case UBI_COMPAT_PRESERVE:
1156 			ubi_msg(ubi, "\"preserve\" compatible internal volume %d:%d found",
1157 				vol_id, lnum);
1158 			err = add_to_list(ai, pnum, vol_id, lnum,
1159 					  ec, 0, &ai->alien);
1160 			if (err)
1161 				return err;
1162 			return 0;
1163 
1164 		case UBI_COMPAT_REJECT:
1165 			ubi_err(ubi, "incompatible internal volume %d:%d found",
1166 				vol_id, lnum);
1167 			return -EINVAL;
1168 		}
1169 	}
1170 
1171 	if (ec_err)
1172 		ubi_warn(ubi, "valid VID header but corrupted EC header at PEB %d",
1173 			 pnum);
1174 
1175 	if (ubi_is_fm_vol(vol_id))
1176 		err = add_fastmap(ai, pnum, vidh, ec);
1177 	else
1178 		err = ubi_add_to_av(ubi, ai, pnum, ec, vidh, bitflips);
1179 
1180 	if (err)
1181 		return err;
1182 
1183 adjust_mean_ec:
1184 	if (!ec_err) {
1185 		ai->ec_sum += ec;
1186 		ai->ec_count += 1;
1187 		if (ec > ai->max_ec)
1188 			ai->max_ec = ec;
1189 		if (ec < ai->min_ec)
1190 			ai->min_ec = ec;
1191 	}
1192 
1193 	return 0;
1194 }
1195 
1196 /**
1197  * late_analysis - analyze the overall situation with PEB.
1198  * @ubi: UBI device description object
1199  * @ai: attaching information
1200  *
1201  * This is a helper function which takes a look what PEBs we have after we
1202  * gather information about all of them ("ai" is compete). It decides whether
1203  * the flash is empty and should be formatted of whether there are too many
1204  * corrupted PEBs and we should not attach this MTD device. Returns zero if we
1205  * should proceed with attaching the MTD device, and %-EINVAL if we should not.
1206  */
late_analysis(struct ubi_device * ubi,struct ubi_attach_info * ai)1207 static int late_analysis(struct ubi_device *ubi, struct ubi_attach_info *ai)
1208 {
1209 	struct ubi_ainf_peb *aeb;
1210 	int max_corr, peb_count;
1211 
1212 	peb_count = ubi->peb_count - ai->bad_peb_count - ai->alien_peb_count;
1213 	max_corr = peb_count / 20 ?: 8;
1214 
1215 	/*
1216 	 * Few corrupted PEBs is not a problem and may be just a result of
1217 	 * unclean reboots. However, many of them may indicate some problems
1218 	 * with the flash HW or driver.
1219 	 */
1220 	if (ai->corr_peb_count) {
1221 		ubi_err(ubi, "%d PEBs are corrupted and preserved",
1222 			ai->corr_peb_count);
1223 		pr_err("Corrupted PEBs are:");
1224 		list_for_each_entry(aeb, &ai->corr, u.list)
1225 			pr_cont(" %d", aeb->pnum);
1226 		pr_cont("\n");
1227 
1228 		/*
1229 		 * If too many PEBs are corrupted, we refuse attaching,
1230 		 * otherwise, only print a warning.
1231 		 */
1232 		if (ai->corr_peb_count >= max_corr) {
1233 			ubi_err(ubi, "too many corrupted PEBs, refusing");
1234 			return -EINVAL;
1235 		}
1236 	}
1237 
1238 	if (ai->empty_peb_count + ai->maybe_bad_peb_count == peb_count) {
1239 		/*
1240 		 * All PEBs are empty, or almost all - a couple PEBs look like
1241 		 * they may be bad PEBs which were not marked as bad yet.
1242 		 *
1243 		 * This piece of code basically tries to distinguish between
1244 		 * the following situations:
1245 		 *
1246 		 * 1. Flash is empty, but there are few bad PEBs, which are not
1247 		 *    marked as bad so far, and which were read with error. We
1248 		 *    want to go ahead and format this flash. While formatting,
1249 		 *    the faulty PEBs will probably be marked as bad.
1250 		 *
1251 		 * 2. Flash contains non-UBI data and we do not want to format
1252 		 *    it and destroy possibly important information.
1253 		 */
1254 		if (ai->maybe_bad_peb_count <= 2) {
1255 			ai->is_empty = 1;
1256 			ubi_msg(ubi, "empty MTD device detected");
1257 			get_random_bytes(&ubi->image_seq,
1258 					 sizeof(ubi->image_seq));
1259 		} else {
1260 			ubi_err(ubi, "MTD device is not UBI-formatted and possibly contains non-UBI data - refusing it");
1261 			return -EINVAL;
1262 		}
1263 
1264 	}
1265 
1266 	return 0;
1267 }
1268 
1269 /**
1270  * destroy_av - free volume attaching information.
1271  * @av: volume attaching information
1272  * @ai: attaching information
1273  * @list: put the aeb elements in there if !NULL, otherwise free them
1274  *
1275  * This function destroys the volume attaching information.
1276  */
destroy_av(struct ubi_attach_info * ai,struct ubi_ainf_volume * av,struct list_head * list)1277 static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av,
1278 		       struct list_head *list)
1279 {
1280 	struct ubi_ainf_peb *aeb;
1281 	struct rb_node *this = av->root.rb_node;
1282 
1283 	while (this) {
1284 		if (this->rb_left)
1285 			this = this->rb_left;
1286 		else if (this->rb_right)
1287 			this = this->rb_right;
1288 		else {
1289 			aeb = rb_entry(this, struct ubi_ainf_peb, u.rb);
1290 			this = rb_parent(this);
1291 			if (this) {
1292 				if (this->rb_left == &aeb->u.rb)
1293 					this->rb_left = NULL;
1294 				else
1295 					this->rb_right = NULL;
1296 			}
1297 
1298 			if (list)
1299 				list_add_tail(&aeb->u.list, list);
1300 			else
1301 				ubi_free_aeb(ai, aeb);
1302 		}
1303 	}
1304 	kfree(av);
1305 }
1306 
1307 /**
1308  * destroy_ai - destroy attaching information.
1309  * @ai: attaching information
1310  */
destroy_ai(struct ubi_attach_info * ai)1311 static void destroy_ai(struct ubi_attach_info *ai)
1312 {
1313 	struct ubi_ainf_peb *aeb, *aeb_tmp;
1314 	struct ubi_ainf_volume *av;
1315 	struct rb_node *rb;
1316 
1317 	list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, u.list) {
1318 		list_del(&aeb->u.list);
1319 		ubi_free_aeb(ai, aeb);
1320 	}
1321 	list_for_each_entry_safe(aeb, aeb_tmp, &ai->erase, u.list) {
1322 		list_del(&aeb->u.list);
1323 		ubi_free_aeb(ai, aeb);
1324 	}
1325 	list_for_each_entry_safe(aeb, aeb_tmp, &ai->corr, u.list) {
1326 		list_del(&aeb->u.list);
1327 		ubi_free_aeb(ai, aeb);
1328 	}
1329 	list_for_each_entry_safe(aeb, aeb_tmp, &ai->free, u.list) {
1330 		list_del(&aeb->u.list);
1331 		ubi_free_aeb(ai, aeb);
1332 	}
1333 	list_for_each_entry_safe(aeb, aeb_tmp, &ai->fastmap, u.list) {
1334 		list_del(&aeb->u.list);
1335 		ubi_free_aeb(ai, aeb);
1336 	}
1337 
1338 	/* Destroy the volume RB-tree */
1339 	rb = ai->volumes.rb_node;
1340 	while (rb) {
1341 		if (rb->rb_left)
1342 			rb = rb->rb_left;
1343 		else if (rb->rb_right)
1344 			rb = rb->rb_right;
1345 		else {
1346 			av = rb_entry(rb, struct ubi_ainf_volume, rb);
1347 
1348 			rb = rb_parent(rb);
1349 			if (rb) {
1350 				if (rb->rb_left == &av->rb)
1351 					rb->rb_left = NULL;
1352 				else
1353 					rb->rb_right = NULL;
1354 			}
1355 
1356 			destroy_av(ai, av, NULL);
1357 		}
1358 	}
1359 
1360 	kmem_cache_destroy(ai->aeb_slab_cache);
1361 	kfree(ai);
1362 }
1363 
1364 /**
1365  * scan_all - scan entire MTD device.
1366  * @ubi: UBI device description object
1367  * @ai: attach info object
1368  * @start: start scanning at this PEB
1369  *
1370  * This function does full scanning of an MTD device and returns complete
1371  * information about it in form of a "struct ubi_attach_info" object. In case
1372  * of failure, an error code is returned.
1373  */
scan_all(struct ubi_device * ubi,struct ubi_attach_info * ai,int start)1374 static int scan_all(struct ubi_device *ubi, struct ubi_attach_info *ai,
1375 		    int start)
1376 {
1377 	int err, pnum;
1378 	struct rb_node *rb1, *rb2;
1379 	struct ubi_ainf_volume *av;
1380 	struct ubi_ainf_peb *aeb;
1381 
1382 	err = -ENOMEM;
1383 
1384 	ai->ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1385 	if (!ai->ech)
1386 		return err;
1387 
1388 	ai->vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
1389 	if (!ai->vidb)
1390 		goto out_ech;
1391 
1392 	for (pnum = start; pnum < ubi->peb_count; pnum++) {
1393 		cond_resched();
1394 
1395 		dbg_gen("process PEB %d", pnum);
1396 		err = scan_peb(ubi, ai, pnum, false);
1397 		if (err < 0)
1398 			goto out_vidh;
1399 	}
1400 
1401 	ubi_msg(ubi, "scanning is finished");
1402 
1403 	/* Calculate mean erase counter */
1404 	if (ai->ec_count)
1405 		ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count);
1406 
1407 	err = late_analysis(ubi, ai);
1408 	if (err)
1409 		goto out_vidh;
1410 
1411 	/*
1412 	 * In case of unknown erase counter we use the mean erase counter
1413 	 * value.
1414 	 */
1415 	ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1416 		ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
1417 			if (aeb->ec == UBI_UNKNOWN)
1418 				aeb->ec = ai->mean_ec;
1419 	}
1420 
1421 	list_for_each_entry(aeb, &ai->free, u.list) {
1422 		if (aeb->ec == UBI_UNKNOWN)
1423 			aeb->ec = ai->mean_ec;
1424 	}
1425 
1426 	list_for_each_entry(aeb, &ai->corr, u.list)
1427 		if (aeb->ec == UBI_UNKNOWN)
1428 			aeb->ec = ai->mean_ec;
1429 
1430 	list_for_each_entry(aeb, &ai->erase, u.list)
1431 		if (aeb->ec == UBI_UNKNOWN)
1432 			aeb->ec = ai->mean_ec;
1433 
1434 	err = self_check_ai(ubi, ai);
1435 	if (err)
1436 		goto out_vidh;
1437 
1438 	ubi_free_vid_buf(ai->vidb);
1439 	kfree(ai->ech);
1440 
1441 	return 0;
1442 
1443 out_vidh:
1444 	ubi_free_vid_buf(ai->vidb);
1445 out_ech:
1446 	kfree(ai->ech);
1447 	return err;
1448 }
1449 
alloc_ai(void)1450 static struct ubi_attach_info *alloc_ai(void)
1451 {
1452 	struct ubi_attach_info *ai;
1453 
1454 	ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL);
1455 	if (!ai)
1456 		return ai;
1457 
1458 	INIT_LIST_HEAD(&ai->corr);
1459 	INIT_LIST_HEAD(&ai->free);
1460 	INIT_LIST_HEAD(&ai->erase);
1461 	INIT_LIST_HEAD(&ai->alien);
1462 	INIT_LIST_HEAD(&ai->fastmap);
1463 	ai->volumes = RB_ROOT;
1464 	ai->aeb_slab_cache = kmem_cache_create("ubi_aeb_slab_cache",
1465 					       sizeof(struct ubi_ainf_peb),
1466 					       0, 0, NULL);
1467 	if (!ai->aeb_slab_cache) {
1468 		kfree(ai);
1469 		ai = NULL;
1470 	}
1471 
1472 	return ai;
1473 }
1474 
1475 #ifdef CONFIG_MTD_UBI_FASTMAP
1476 
1477 /**
1478  * scan_fast - try to find a fastmap and attach from it.
1479  * @ubi: UBI device description object
1480  * @ai: attach info object
1481  *
1482  * Returns 0 on success, negative return values indicate an internal
1483  * error.
1484  * UBI_NO_FASTMAP denotes that no fastmap was found.
1485  * UBI_BAD_FASTMAP denotes that the found fastmap was invalid.
1486  */
scan_fast(struct ubi_device * ubi,struct ubi_attach_info ** ai)1487 static int scan_fast(struct ubi_device *ubi, struct ubi_attach_info **ai)
1488 {
1489 	int err, pnum;
1490 	struct ubi_attach_info *scan_ai;
1491 
1492 	err = -ENOMEM;
1493 
1494 	scan_ai = alloc_ai();
1495 	if (!scan_ai)
1496 		goto out;
1497 
1498 	scan_ai->ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1499 	if (!scan_ai->ech)
1500 		goto out_ai;
1501 
1502 	scan_ai->vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
1503 	if (!scan_ai->vidb)
1504 		goto out_ech;
1505 
1506 	for (pnum = 0; pnum < UBI_FM_MAX_START; pnum++) {
1507 		cond_resched();
1508 
1509 		dbg_gen("process PEB %d", pnum);
1510 		err = scan_peb(ubi, scan_ai, pnum, true);
1511 		if (err < 0)
1512 			goto out_vidh;
1513 	}
1514 
1515 	ubi_free_vid_buf(scan_ai->vidb);
1516 	kfree(scan_ai->ech);
1517 
1518 	if (scan_ai->force_full_scan)
1519 		err = UBI_NO_FASTMAP;
1520 	else
1521 		err = ubi_scan_fastmap(ubi, *ai, scan_ai);
1522 
1523 	if (err) {
1524 		/*
1525 		 * Didn't attach via fastmap, do a full scan but reuse what
1526 		 * we've aready scanned.
1527 		 */
1528 		destroy_ai(*ai);
1529 		*ai = scan_ai;
1530 	} else
1531 		destroy_ai(scan_ai);
1532 
1533 	return err;
1534 
1535 out_vidh:
1536 	ubi_free_vid_buf(scan_ai->vidb);
1537 out_ech:
1538 	kfree(scan_ai->ech);
1539 out_ai:
1540 	destroy_ai(scan_ai);
1541 out:
1542 	return err;
1543 }
1544 
1545 #endif
1546 
1547 /**
1548  * ubi_attach - attach an MTD device.
1549  * @ubi: UBI device descriptor
1550  * @force_scan: if set to non-zero attach by scanning
1551  *
1552  * This function returns zero in case of success and a negative error code in
1553  * case of failure.
1554  */
ubi_attach(struct ubi_device * ubi,int force_scan)1555 int ubi_attach(struct ubi_device *ubi, int force_scan)
1556 {
1557 	int err;
1558 	struct ubi_attach_info *ai;
1559 
1560 	ai = alloc_ai();
1561 	if (!ai)
1562 		return -ENOMEM;
1563 
1564 #ifdef CONFIG_MTD_UBI_FASTMAP
1565 	/* On small flash devices we disable fastmap in any case. */
1566 	if ((int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd) <= UBI_FM_MAX_START) {
1567 		ubi->fm_disabled = 1;
1568 		force_scan = 1;
1569 	}
1570 
1571 	if (force_scan)
1572 		err = scan_all(ubi, ai, 0);
1573 	else {
1574 		err = scan_fast(ubi, &ai);
1575 		if (err > 0 || mtd_is_eccerr(err)) {
1576 			if (err != UBI_NO_FASTMAP) {
1577 				destroy_ai(ai);
1578 				ai = alloc_ai();
1579 				if (!ai)
1580 					return -ENOMEM;
1581 
1582 				err = scan_all(ubi, ai, 0);
1583 			} else {
1584 				err = scan_all(ubi, ai, UBI_FM_MAX_START);
1585 			}
1586 		}
1587 	}
1588 #else
1589 	err = scan_all(ubi, ai, 0);
1590 #endif
1591 	if (err)
1592 		goto out_ai;
1593 
1594 	ubi->bad_peb_count = ai->bad_peb_count;
1595 	ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count;
1596 	ubi->corr_peb_count = ai->corr_peb_count;
1597 	ubi->max_ec = ai->max_ec;
1598 	ubi->mean_ec = ai->mean_ec;
1599 	dbg_gen("max. sequence number:       %llu", ai->max_sqnum);
1600 
1601 	err = ubi_read_volume_table(ubi, ai);
1602 	if (err)
1603 		goto out_ai;
1604 
1605 	err = ubi_wl_init(ubi, ai);
1606 	if (err)
1607 		goto out_vtbl;
1608 
1609 	err = ubi_eba_init(ubi, ai);
1610 	if (err)
1611 		goto out_wl;
1612 
1613 #ifdef CONFIG_MTD_UBI_FASTMAP
1614 	if (ubi->fm && ubi_dbg_chk_fastmap(ubi)) {
1615 		struct ubi_attach_info *scan_ai;
1616 
1617 		scan_ai = alloc_ai();
1618 		if (!scan_ai) {
1619 			err = -ENOMEM;
1620 			goto out_wl;
1621 		}
1622 
1623 		err = scan_all(ubi, scan_ai, 0);
1624 		if (err) {
1625 			destroy_ai(scan_ai);
1626 			goto out_wl;
1627 		}
1628 
1629 		err = self_check_eba(ubi, ai, scan_ai);
1630 		destroy_ai(scan_ai);
1631 
1632 		if (err)
1633 			goto out_wl;
1634 	}
1635 #endif
1636 
1637 	destroy_ai(ai);
1638 	return 0;
1639 
1640 out_wl:
1641 	ubi_wl_close(ubi);
1642 out_vtbl:
1643 	ubi_free_all_volumes(ubi);
1644 	vfree(ubi->vtbl);
1645 out_ai:
1646 	destroy_ai(ai);
1647 	return err;
1648 }
1649 
1650 /**
1651  * self_check_ai - check the attaching information.
1652  * @ubi: UBI device description object
1653  * @ai: attaching information
1654  *
1655  * This function returns zero if the attaching information is all right, and a
1656  * negative error code if not or if an error occurred.
1657  */
self_check_ai(struct ubi_device * ubi,struct ubi_attach_info * ai)1658 static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai)
1659 {
1660 	struct ubi_vid_io_buf *vidb = ai->vidb;
1661 	struct ubi_vid_hdr *vidh = ubi_get_vid_hdr(vidb);
1662 	int pnum, err, vols_found = 0;
1663 	struct rb_node *rb1, *rb2;
1664 	struct ubi_ainf_volume *av;
1665 	struct ubi_ainf_peb *aeb, *last_aeb;
1666 	uint8_t *buf;
1667 
1668 	if (!ubi_dbg_chk_gen(ubi))
1669 		return 0;
1670 
1671 	/*
1672 	 * At first, check that attaching information is OK.
1673 	 */
1674 	ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1675 		int leb_count = 0;
1676 
1677 		cond_resched();
1678 
1679 		vols_found += 1;
1680 
1681 		if (ai->is_empty) {
1682 			ubi_err(ubi, "bad is_empty flag");
1683 			goto bad_av;
1684 		}
1685 
1686 		if (av->vol_id < 0 || av->highest_lnum < 0 ||
1687 		    av->leb_count < 0 || av->vol_type < 0 || av->used_ebs < 0 ||
1688 		    av->data_pad < 0 || av->last_data_size < 0) {
1689 			ubi_err(ubi, "negative values");
1690 			goto bad_av;
1691 		}
1692 
1693 		if (av->vol_id >= UBI_MAX_VOLUMES &&
1694 		    av->vol_id < UBI_INTERNAL_VOL_START) {
1695 			ubi_err(ubi, "bad vol_id");
1696 			goto bad_av;
1697 		}
1698 
1699 		if (av->vol_id > ai->highest_vol_id) {
1700 			ubi_err(ubi, "highest_vol_id is %d, but vol_id %d is there",
1701 				ai->highest_vol_id, av->vol_id);
1702 			goto out;
1703 		}
1704 
1705 		if (av->vol_type != UBI_DYNAMIC_VOLUME &&
1706 		    av->vol_type != UBI_STATIC_VOLUME) {
1707 			ubi_err(ubi, "bad vol_type");
1708 			goto bad_av;
1709 		}
1710 
1711 		if (av->data_pad > ubi->leb_size / 2) {
1712 			ubi_err(ubi, "bad data_pad");
1713 			goto bad_av;
1714 		}
1715 
1716 		last_aeb = NULL;
1717 		ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1718 			cond_resched();
1719 
1720 			last_aeb = aeb;
1721 			leb_count += 1;
1722 
1723 			if (aeb->pnum < 0 || aeb->ec < 0) {
1724 				ubi_err(ubi, "negative values");
1725 				goto bad_aeb;
1726 			}
1727 
1728 			if (aeb->ec < ai->min_ec) {
1729 				ubi_err(ubi, "bad ai->min_ec (%d), %d found",
1730 					ai->min_ec, aeb->ec);
1731 				goto bad_aeb;
1732 			}
1733 
1734 			if (aeb->ec > ai->max_ec) {
1735 				ubi_err(ubi, "bad ai->max_ec (%d), %d found",
1736 					ai->max_ec, aeb->ec);
1737 				goto bad_aeb;
1738 			}
1739 
1740 			if (aeb->pnum >= ubi->peb_count) {
1741 				ubi_err(ubi, "too high PEB number %d, total PEBs %d",
1742 					aeb->pnum, ubi->peb_count);
1743 				goto bad_aeb;
1744 			}
1745 
1746 			if (av->vol_type == UBI_STATIC_VOLUME) {
1747 				if (aeb->lnum >= av->used_ebs) {
1748 					ubi_err(ubi, "bad lnum or used_ebs");
1749 					goto bad_aeb;
1750 				}
1751 			} else {
1752 				if (av->used_ebs != 0) {
1753 					ubi_err(ubi, "non-zero used_ebs");
1754 					goto bad_aeb;
1755 				}
1756 			}
1757 
1758 			if (aeb->lnum > av->highest_lnum) {
1759 				ubi_err(ubi, "incorrect highest_lnum or lnum");
1760 				goto bad_aeb;
1761 			}
1762 		}
1763 
1764 		if (av->leb_count != leb_count) {
1765 			ubi_err(ubi, "bad leb_count, %d objects in the tree",
1766 				leb_count);
1767 			goto bad_av;
1768 		}
1769 
1770 		if (!last_aeb)
1771 			continue;
1772 
1773 		aeb = last_aeb;
1774 
1775 		if (aeb->lnum != av->highest_lnum) {
1776 			ubi_err(ubi, "bad highest_lnum");
1777 			goto bad_aeb;
1778 		}
1779 	}
1780 
1781 	if (vols_found != ai->vols_found) {
1782 		ubi_err(ubi, "bad ai->vols_found %d, should be %d",
1783 			ai->vols_found, vols_found);
1784 		goto out;
1785 	}
1786 
1787 	/* Check that attaching information is correct */
1788 	ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1789 		last_aeb = NULL;
1790 		ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1791 			int vol_type;
1792 
1793 			cond_resched();
1794 
1795 			last_aeb = aeb;
1796 
1797 			err = ubi_io_read_vid_hdr(ubi, aeb->pnum, vidb, 1);
1798 			if (err && err != UBI_IO_BITFLIPS) {
1799 				ubi_err(ubi, "VID header is not OK (%d)",
1800 					err);
1801 				if (err > 0)
1802 					err = -EIO;
1803 				return err;
1804 			}
1805 
1806 			vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1807 				   UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1808 			if (av->vol_type != vol_type) {
1809 				ubi_err(ubi, "bad vol_type");
1810 				goto bad_vid_hdr;
1811 			}
1812 
1813 			if (aeb->sqnum != be64_to_cpu(vidh->sqnum)) {
1814 				ubi_err(ubi, "bad sqnum %llu", aeb->sqnum);
1815 				goto bad_vid_hdr;
1816 			}
1817 
1818 			if (av->vol_id != be32_to_cpu(vidh->vol_id)) {
1819 				ubi_err(ubi, "bad vol_id %d", av->vol_id);
1820 				goto bad_vid_hdr;
1821 			}
1822 
1823 			if (av->compat != vidh->compat) {
1824 				ubi_err(ubi, "bad compat %d", vidh->compat);
1825 				goto bad_vid_hdr;
1826 			}
1827 
1828 			if (aeb->lnum != be32_to_cpu(vidh->lnum)) {
1829 				ubi_err(ubi, "bad lnum %d", aeb->lnum);
1830 				goto bad_vid_hdr;
1831 			}
1832 
1833 			if (av->used_ebs != be32_to_cpu(vidh->used_ebs)) {
1834 				ubi_err(ubi, "bad used_ebs %d", av->used_ebs);
1835 				goto bad_vid_hdr;
1836 			}
1837 
1838 			if (av->data_pad != be32_to_cpu(vidh->data_pad)) {
1839 				ubi_err(ubi, "bad data_pad %d", av->data_pad);
1840 				goto bad_vid_hdr;
1841 			}
1842 		}
1843 
1844 		if (!last_aeb)
1845 			continue;
1846 
1847 		if (av->highest_lnum != be32_to_cpu(vidh->lnum)) {
1848 			ubi_err(ubi, "bad highest_lnum %d", av->highest_lnum);
1849 			goto bad_vid_hdr;
1850 		}
1851 
1852 		if (av->last_data_size != be32_to_cpu(vidh->data_size)) {
1853 			ubi_err(ubi, "bad last_data_size %d",
1854 				av->last_data_size);
1855 			goto bad_vid_hdr;
1856 		}
1857 	}
1858 
1859 	/*
1860 	 * Make sure that all the physical eraseblocks are in one of the lists
1861 	 * or trees.
1862 	 */
1863 	buf = kzalloc(ubi->peb_count, GFP_KERNEL);
1864 	if (!buf)
1865 		return -ENOMEM;
1866 
1867 	for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1868 		err = ubi_io_is_bad(ubi, pnum);
1869 		if (err < 0) {
1870 			kfree(buf);
1871 			return err;
1872 		} else if (err)
1873 			buf[pnum] = 1;
1874 	}
1875 
1876 	ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb)
1877 		ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
1878 			buf[aeb->pnum] = 1;
1879 
1880 	list_for_each_entry(aeb, &ai->free, u.list)
1881 		buf[aeb->pnum] = 1;
1882 
1883 	list_for_each_entry(aeb, &ai->corr, u.list)
1884 		buf[aeb->pnum] = 1;
1885 
1886 	list_for_each_entry(aeb, &ai->erase, u.list)
1887 		buf[aeb->pnum] = 1;
1888 
1889 	list_for_each_entry(aeb, &ai->alien, u.list)
1890 		buf[aeb->pnum] = 1;
1891 
1892 	err = 0;
1893 	for (pnum = 0; pnum < ubi->peb_count; pnum++)
1894 		if (!buf[pnum]) {
1895 			ubi_err(ubi, "PEB %d is not referred", pnum);
1896 			err = 1;
1897 		}
1898 
1899 	kfree(buf);
1900 	if (err)
1901 		goto out;
1902 	return 0;
1903 
1904 bad_aeb:
1905 	ubi_err(ubi, "bad attaching information about LEB %d", aeb->lnum);
1906 	ubi_dump_aeb(aeb, 0);
1907 	ubi_dump_av(av);
1908 	goto out;
1909 
1910 bad_av:
1911 	ubi_err(ubi, "bad attaching information about volume %d", av->vol_id);
1912 	ubi_dump_av(av);
1913 	goto out;
1914 
1915 bad_vid_hdr:
1916 	ubi_err(ubi, "bad attaching information about volume %d", av->vol_id);
1917 	ubi_dump_av(av);
1918 	ubi_dump_vid_hdr(vidh);
1919 
1920 out:
1921 	dump_stack();
1922 	return -EINVAL;
1923 }
1924