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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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 */
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
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 */
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 /* fall through */
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 */
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 */
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 */
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 */
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
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 */
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 */
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_internal_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 */
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 }