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1/*
2 * Copyright (c) International Business Machines Corp., 2006
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 *
18 * Author: Artem Bityutskiy (Битюцкий Артём)
19 */
20
21/*
22 * UBI scanning sub-system.
23 *
24 * This sub-system is responsible for scanning the flash media, checking UBI
25 * headers and providing complete information about the UBI flash image.
26 *
27 * The scanning information is represented by a &struct ubi_scan_info' object.
28 * Information about found volumes is represented by &struct ubi_scan_volume
29 * objects which are kept in volume RB-tree with root at the @volumes field.
30 * The RB-tree is indexed by the volume ID.
31 *
32 * Scanned logical eraseblocks are represented by &struct ubi_scan_leb objects.
33 * These objects are kept in per-volume RB-trees with the root at the
34 * corresponding &struct ubi_scan_volume object. To put it differently, we keep
35 * an RB-tree of per-volume objects and each of these objects is the root of
36 * RB-tree of per-eraseblock objects.
37 *
38 * Corrupted physical eraseblocks are put to the @corr list, free physical
39 * eraseblocks are put to the @free list and the physical eraseblock to be
40 * erased are put to the @erase list.
41 *
42 * About corruptions
43 * ~~~~~~~~~~~~~~~~~
44 *
45 * UBI protects EC and VID headers with CRC-32 checksums, so it can detect
46 * whether the headers are corrupted or not. Sometimes UBI also protects the
47 * data with CRC-32, e.g., when it executes the atomic LEB change operation, or
48 * when it moves the contents of a PEB for wear-leveling purposes.
49 *
50 * UBI tries to distinguish between 2 types of corruptions.
51 *
52 * 1. Corruptions caused by power cuts. These are expected corruptions and UBI
53 * tries to handle them gracefully, without printing too many warnings and
54 * error messages. The idea is that we do not lose important data in these case
55 * - we may lose only the data which was being written to the media just before
56 * the power cut happened, and the upper layers (e.g., UBIFS) are supposed to
57 * handle such data losses (e.g., by using the FS journal).
58 *
59 * When UBI detects a corruption (CRC-32 mismatch) in a PEB, and it looks like
60 * the reason is a power cut, UBI puts this PEB to the @erase list, and all
61 * PEBs in the @erase list are scheduled for erasure later.
62 *
63 * 2. Unexpected corruptions which are not caused by power cuts. During
64 * scanning, such PEBs are put to the @corr list and UBI preserves them.
65 * Obviously, this lessens the amount of available PEBs, and if at some point
66 * UBI runs out of free PEBs, it switches to R/O mode. UBI also loudly informs
67 * about such PEBs every time the MTD device is attached.
68 *
69 * However, it is difficult to reliably distinguish between these types of
70 * corruptions and UBI's strategy is as follows. UBI assumes corruption type 2
71 * if the VID header is corrupted and the data area does not contain all 0xFFs,
72 * and there were no bit-flips or integrity errors while reading the data area.
73 * Otherwise UBI assumes corruption type 1. So the decision criteria are as
74 * follows.
75 * o If the data area contains only 0xFFs, there is no data, and it is safe
76 * to just erase this PEB - this is corruption type 1.
77 * o If the data area has bit-flips or data integrity errors (ECC errors on
78 * NAND), it is probably a PEB which was being erased when power cut
79 * happened, so this is corruption type 1. However, this is just a guess,
80 * which might be wrong.
81 * o Otherwise this it corruption type 2.
82 */
83
84#include <linux/err.h>
85#include <linux/slab.h>
86#include <linux/crc32.h>
87#include <linux/math64.h>
88#include <linux/random.h>
89#include "ubi.h"
90
91#ifdef CONFIG_MTD_UBI_DEBUG
92static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si);
93#else
94#define paranoid_check_si(ubi, si) 0
95#endif
96
97/* Temporary variables used during scanning */
98static struct ubi_ec_hdr *ech;
99static struct ubi_vid_hdr *vidh;
100
101/**
102 * add_to_list - add physical eraseblock to a list.
103 * @si: scanning information
104 * @pnum: physical eraseblock number to add
105 * @ec: erase counter of the physical eraseblock
106 * @to_head: if not zero, add to the head of the list
107 * @list: the list to add to
108 *
109 * This function adds physical eraseblock @pnum to free, erase, or alien lists.
110 * If @to_head is not zero, PEB will be added to the head of the list, which
111 * basically means it will be processed first later. E.g., we add corrupted
112 * PEBs (corrupted due to power cuts) to the head of the erase list to make
113 * sure we erase them first and get rid of corruptions ASAP. This function
114 * returns zero in case of success and a negative error code in case of
115 * failure.
116 */
117static int add_to_list(struct ubi_scan_info *si, int pnum, int ec, int to_head,
118 struct list_head *list)
119{
120 struct ubi_scan_leb *seb;
121
122 if (list == &si->free) {
123 dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
124 } else if (list == &si->erase) {
125 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
126 } else if (list == &si->alien) {
127 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
128 si->alien_peb_count += 1;
129 } else
130 BUG();
131
132 seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);
133 if (!seb)
134 return -ENOMEM;
135
136 seb->pnum = pnum;
137 seb->ec = ec;
138 if (to_head)
139 list_add(&seb->u.list, list);
140 else
141 list_add_tail(&seb->u.list, list);
142 return 0;
143}
144
145/**
146 * add_corrupted - add a corrupted physical eraseblock.
147 * @si: scanning information
148 * @pnum: physical eraseblock number to add
149 * @ec: erase counter of the physical eraseblock
150 *
151 * This function adds corrupted physical eraseblock @pnum to the 'corr' list.
152 * The corruption was presumably not caused by a power cut. Returns zero in
153 * case of success and a negative error code in case of failure.
154 */
155static int add_corrupted(struct ubi_scan_info *si, int pnum, int ec)
156{
157 struct ubi_scan_leb *seb;
158
159 dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
160
161 seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);
162 if (!seb)
163 return -ENOMEM;
164
165 si->corr_peb_count += 1;
166 seb->pnum = pnum;
167 seb->ec = ec;
168 list_add(&seb->u.list, &si->corr);
169 return 0;
170}
171
172/**
173 * validate_vid_hdr - check volume identifier header.
174 * @vid_hdr: the volume identifier header to check
175 * @sv: information about the volume this logical eraseblock belongs to
176 * @pnum: physical eraseblock number the VID header came from
177 *
178 * This function checks that data stored in @vid_hdr is consistent. Returns
179 * non-zero if an inconsistency was found and zero if not.
180 *
181 * Note, UBI does sanity check of everything it reads from the flash media.
182 * Most of the checks are done in the I/O sub-system. Here we check that the
183 * information in the VID header is consistent to the information in other VID
184 * headers of the same volume.
185 */
186static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
187 const struct ubi_scan_volume *sv, int pnum)
188{
189 int vol_type = vid_hdr->vol_type;
190 int vol_id = be32_to_cpu(vid_hdr->vol_id);
191 int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
192 int data_pad = be32_to_cpu(vid_hdr->data_pad);
193
194 if (sv->leb_count != 0) {
195 int sv_vol_type;
196
197 /*
198 * This is not the first logical eraseblock belonging to this
199 * volume. Ensure that the data in its VID header is consistent
200 * to the data in previous logical eraseblock headers.
201 */
202
203 if (vol_id != sv->vol_id) {
204 dbg_err("inconsistent vol_id");
205 goto bad;
206 }
207
208 if (sv->vol_type == UBI_STATIC_VOLUME)
209 sv_vol_type = UBI_VID_STATIC;
210 else
211 sv_vol_type = UBI_VID_DYNAMIC;
212
213 if (vol_type != sv_vol_type) {
214 dbg_err("inconsistent vol_type");
215 goto bad;
216 }
217
218 if (used_ebs != sv->used_ebs) {
219 dbg_err("inconsistent used_ebs");
220 goto bad;
221 }
222
223 if (data_pad != sv->data_pad) {
224 dbg_err("inconsistent data_pad");
225 goto bad;
226 }
227 }
228
229 return 0;
230
231bad:
232 ubi_err("inconsistent VID header at PEB %d", pnum);
233 ubi_dbg_dump_vid_hdr(vid_hdr);
234 ubi_dbg_dump_sv(sv);
235 return -EINVAL;
236}
237
238/**
239 * add_volume - add volume to the scanning information.
240 * @si: scanning information
241 * @vol_id: ID of the volume to add
242 * @pnum: physical eraseblock number
243 * @vid_hdr: volume identifier header
244 *
245 * If the volume corresponding to the @vid_hdr logical eraseblock is already
246 * present in the scanning information, this function does nothing. Otherwise
247 * it adds corresponding volume to the scanning information. Returns a pointer
248 * to the scanning volume object in case of success and a negative error code
249 * in case of failure.
250 */
251static struct ubi_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id,
252 int pnum,
253 const struct ubi_vid_hdr *vid_hdr)
254{
255 struct ubi_scan_volume *sv;
256 struct rb_node **p = &si->volumes.rb_node, *parent = NULL;
257
258 ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
259
260 /* Walk the volume RB-tree to look if this volume is already present */
261 while (*p) {
262 parent = *p;
263 sv = rb_entry(parent, struct ubi_scan_volume, rb);
264
265 if (vol_id == sv->vol_id)
266 return sv;
267
268 if (vol_id > sv->vol_id)
269 p = &(*p)->rb_left;
270 else
271 p = &(*p)->rb_right;
272 }
273
274 /* The volume is absent - add it */
275 sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL);
276 if (!sv)
277 return ERR_PTR(-ENOMEM);
278
279 sv->highest_lnum = sv->leb_count = 0;
280 sv->vol_id = vol_id;
281 sv->root = RB_ROOT;
282 sv->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
283 sv->data_pad = be32_to_cpu(vid_hdr->data_pad);
284 sv->compat = vid_hdr->compat;
285 sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
286 : UBI_STATIC_VOLUME;
287 if (vol_id > si->highest_vol_id)
288 si->highest_vol_id = vol_id;
289
290 rb_link_node(&sv->rb, parent, p);
291 rb_insert_color(&sv->rb, &si->volumes);
292 si->vols_found += 1;
293 dbg_bld("added volume %d", vol_id);
294 return sv;
295}
296
297/**
298 * compare_lebs - find out which logical eraseblock is newer.
299 * @ubi: UBI device description object
300 * @seb: first logical eraseblock to compare
301 * @pnum: physical eraseblock number of the second logical eraseblock to
302 * compare
303 * @vid_hdr: volume identifier header of the second logical eraseblock
304 *
305 * This function compares 2 copies of a LEB and informs which one is newer. In
306 * case of success this function returns a positive value, in case of failure, a
307 * negative error code is returned. The success return codes use the following
308 * bits:
309 * o bit 0 is cleared: the first PEB (described by @seb) is newer than the
310 * second PEB (described by @pnum and @vid_hdr);
311 * o bit 0 is set: the second PEB is newer;
312 * o bit 1 is cleared: no bit-flips were detected in the newer LEB;
313 * o bit 1 is set: bit-flips were detected in the newer LEB;
314 * o bit 2 is cleared: the older LEB is not corrupted;
315 * o bit 2 is set: the older LEB is corrupted.
316 */
317static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
318 int pnum, const struct ubi_vid_hdr *vid_hdr)
319{
320 void *buf;
321 int len, err, second_is_newer, bitflips = 0, corrupted = 0;
322 uint32_t data_crc, crc;
323 struct ubi_vid_hdr *vh = NULL;
324 unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
325
326 if (sqnum2 == seb->sqnum) {
327 /*
328 * This must be a really ancient UBI image which has been
329 * created before sequence numbers support has been added. At
330 * that times we used 32-bit LEB versions stored in logical
331 * eraseblocks. That was before UBI got into mainline. We do not
332 * support these images anymore. Well, those images still work,
333 * but only if no unclean reboots happened.
334 */
335 ubi_err("unsupported on-flash UBI format\n");
336 return -EINVAL;
337 }
338
339 /* Obviously the LEB with lower sequence counter is older */
340 second_is_newer = !!(sqnum2 > seb->sqnum);
341
342 /*
343 * Now we know which copy is newer. If the copy flag of the PEB with
344 * newer version is not set, then we just return, otherwise we have to
345 * check data CRC. For the second PEB we already have the VID header,
346 * for the first one - we'll need to re-read it from flash.
347 *
348 * Note: this may be optimized so that we wouldn't read twice.
349 */
350
351 if (second_is_newer) {
352 if (!vid_hdr->copy_flag) {
353 /* It is not a copy, so it is newer */
354 dbg_bld("second PEB %d is newer, copy_flag is unset",
355 pnum);
356 return 1;
357 }
358 } else {
359 if (!seb->copy_flag) {
360 /* It is not a copy, so it is newer */
361 dbg_bld("first PEB %d is newer, copy_flag is unset",
362 pnum);
363 return bitflips << 1;
364 }
365
366 vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
367 if (!vh)
368 return -ENOMEM;
369
370 pnum = seb->pnum;
371 err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
372 if (err) {
373 if (err == UBI_IO_BITFLIPS)
374 bitflips = 1;
375 else {
376 dbg_err("VID of PEB %d header is bad, but it "
377 "was OK earlier, err %d", pnum, err);
378 if (err > 0)
379 err = -EIO;
380
381 goto out_free_vidh;
382 }
383 }
384
385 vid_hdr = vh;
386 }
387
388 /* Read the data of the copy and check the CRC */
389
390 len = be32_to_cpu(vid_hdr->data_size);
391 buf = vmalloc(len);
392 if (!buf) {
393 err = -ENOMEM;
394 goto out_free_vidh;
395 }
396
397 err = ubi_io_read_data(ubi, buf, pnum, 0, len);
398 if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
399 goto out_free_buf;
400
401 data_crc = be32_to_cpu(vid_hdr->data_crc);
402 crc = crc32(UBI_CRC32_INIT, buf, len);
403 if (crc != data_crc) {
404 dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
405 pnum, crc, data_crc);
406 corrupted = 1;
407 bitflips = 0;
408 second_is_newer = !second_is_newer;
409 } else {
410 dbg_bld("PEB %d CRC is OK", pnum);
411 bitflips = !!err;
412 }
413
414 vfree(buf);
415 ubi_free_vid_hdr(ubi, vh);
416
417 if (second_is_newer)
418 dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
419 else
420 dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
421
422 return second_is_newer | (bitflips << 1) | (corrupted << 2);
423
424out_free_buf:
425 vfree(buf);
426out_free_vidh:
427 ubi_free_vid_hdr(ubi, vh);
428 return err;
429}
430
431/**
432 * ubi_scan_add_used - add physical eraseblock to the scanning information.
433 * @ubi: UBI device description object
434 * @si: scanning information
435 * @pnum: the physical eraseblock number
436 * @ec: erase counter
437 * @vid_hdr: the volume identifier header
438 * @bitflips: if bit-flips were detected when this physical eraseblock was read
439 *
440 * This function adds information about a used physical eraseblock to the
441 * 'used' tree of the corresponding volume. The function is rather complex
442 * because it has to handle cases when this is not the first physical
443 * eraseblock belonging to the same logical eraseblock, and the newer one has
444 * to be picked, while the older one has to be dropped. This function returns
445 * zero in case of success and a negative error code in case of failure.
446 */
447int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
448 int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
449 int bitflips)
450{
451 int err, vol_id, lnum;
452 unsigned long long sqnum;
453 struct ubi_scan_volume *sv;
454 struct ubi_scan_leb *seb;
455 struct rb_node **p, *parent = NULL;
456
457 vol_id = be32_to_cpu(vid_hdr->vol_id);
458 lnum = be32_to_cpu(vid_hdr->lnum);
459 sqnum = be64_to_cpu(vid_hdr->sqnum);
460
461 dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
462 pnum, vol_id, lnum, ec, sqnum, bitflips);
463
464 sv = add_volume(si, vol_id, pnum, vid_hdr);
465 if (IS_ERR(sv))
466 return PTR_ERR(sv);
467
468 if (si->max_sqnum < sqnum)
469 si->max_sqnum = sqnum;
470
471 /*
472 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
473 * if this is the first instance of this logical eraseblock or not.
474 */
475 p = &sv->root.rb_node;
476 while (*p) {
477 int cmp_res;
478
479 parent = *p;
480 seb = rb_entry(parent, struct ubi_scan_leb, u.rb);
481 if (lnum != seb->lnum) {
482 if (lnum < seb->lnum)
483 p = &(*p)->rb_left;
484 else
485 p = &(*p)->rb_right;
486 continue;
487 }
488
489 /*
490 * There is already a physical eraseblock describing the same
491 * logical eraseblock present.
492 */
493
494 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
495 "EC %d", seb->pnum, seb->sqnum, seb->ec);
496
497 /*
498 * Make sure that the logical eraseblocks have different
499 * sequence numbers. Otherwise the image is bad.
500 *
501 * However, if the sequence number is zero, we assume it must
502 * be an ancient UBI image from the era when UBI did not have
503 * sequence numbers. We still can attach these images, unless
504 * there is a need to distinguish between old and new
505 * eraseblocks, in which case we'll refuse the image in
506 * 'compare_lebs()'. In other words, we attach old clean
507 * images, but refuse attaching old images with duplicated
508 * logical eraseblocks because there was an unclean reboot.
509 */
510 if (seb->sqnum == sqnum && sqnum != 0) {
511 ubi_err("two LEBs with same sequence number %llu",
512 sqnum);
513 ubi_dbg_dump_seb(seb, 0);
514 ubi_dbg_dump_vid_hdr(vid_hdr);
515 return -EINVAL;
516 }
517
518 /*
519 * Now we have to drop the older one and preserve the newer
520 * one.
521 */
522 cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
523 if (cmp_res < 0)
524 return cmp_res;
525
526 if (cmp_res & 1) {
527 /*
528 * This logical eraseblock is newer than the one
529 * found earlier.
530 */
531 err = validate_vid_hdr(vid_hdr, sv, pnum);
532 if (err)
533 return err;
534
535 err = add_to_list(si, seb->pnum, seb->ec, cmp_res & 4,
536 &si->erase);
537 if (err)
538 return err;
539
540 seb->ec = ec;
541 seb->pnum = pnum;
542 seb->scrub = ((cmp_res & 2) || bitflips);
543 seb->copy_flag = vid_hdr->copy_flag;
544 seb->sqnum = sqnum;
545
546 if (sv->highest_lnum == lnum)
547 sv->last_data_size =
548 be32_to_cpu(vid_hdr->data_size);
549
550 return 0;
551 } else {
552 /*
553 * This logical eraseblock is older than the one found
554 * previously.
555 */
556 return add_to_list(si, pnum, ec, cmp_res & 4,
557 &si->erase);
558 }
559 }
560
561 /*
562 * We've met this logical eraseblock for the first time, add it to the
563 * scanning information.
564 */
565
566 err = validate_vid_hdr(vid_hdr, sv, pnum);
567 if (err)
568 return err;
569
570 seb = kmem_cache_alloc(si->scan_leb_slab, GFP_KERNEL);
571 if (!seb)
572 return -ENOMEM;
573
574 seb->ec = ec;
575 seb->pnum = pnum;
576 seb->lnum = lnum;
577 seb->scrub = bitflips;
578 seb->copy_flag = vid_hdr->copy_flag;
579 seb->sqnum = sqnum;
580
581 if (sv->highest_lnum <= lnum) {
582 sv->highest_lnum = lnum;
583 sv->last_data_size = be32_to_cpu(vid_hdr->data_size);
584 }
585
586 sv->leb_count += 1;
587 rb_link_node(&seb->u.rb, parent, p);
588 rb_insert_color(&seb->u.rb, &sv->root);
589 return 0;
590}
591
592/**
593 * ubi_scan_find_sv - find volume in the scanning information.
594 * @si: scanning information
595 * @vol_id: the requested volume ID
596 *
597 * This function returns a pointer to the volume description or %NULL if there
598 * are no data about this volume in the scanning information.
599 */
600struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
601 int vol_id)
602{
603 struct ubi_scan_volume *sv;
604 struct rb_node *p = si->volumes.rb_node;
605
606 while (p) {
607 sv = rb_entry(p, struct ubi_scan_volume, rb);
608
609 if (vol_id == sv->vol_id)
610 return sv;
611
612 if (vol_id > sv->vol_id)
613 p = p->rb_left;
614 else
615 p = p->rb_right;
616 }
617
618 return NULL;
619}
620
621/**
622 * ubi_scan_find_seb - find LEB in the volume scanning information.
623 * @sv: a pointer to the volume scanning information
624 * @lnum: the requested logical eraseblock
625 *
626 * This function returns a pointer to the scanning logical eraseblock or %NULL
627 * if there are no data about it in the scanning volume information.
628 */
629struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
630 int lnum)
631{
632 struct ubi_scan_leb *seb;
633 struct rb_node *p = sv->root.rb_node;
634
635 while (p) {
636 seb = rb_entry(p, struct ubi_scan_leb, u.rb);
637
638 if (lnum == seb->lnum)
639 return seb;
640
641 if (lnum > seb->lnum)
642 p = p->rb_left;
643 else
644 p = p->rb_right;
645 }
646
647 return NULL;
648}
649
650/**
651 * ubi_scan_rm_volume - delete scanning information about a volume.
652 * @si: scanning information
653 * @sv: the volume scanning information to delete
654 */
655void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
656{
657 struct rb_node *rb;
658 struct ubi_scan_leb *seb;
659
660 dbg_bld("remove scanning information about volume %d", sv->vol_id);
661
662 while ((rb = rb_first(&sv->root))) {
663 seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
664 rb_erase(&seb->u.rb, &sv->root);
665 list_add_tail(&seb->u.list, &si->erase);
666 }
667
668 rb_erase(&sv->rb, &si->volumes);
669 kfree(sv);
670 si->vols_found -= 1;
671}
672
673/**
674 * ubi_scan_erase_peb - erase a physical eraseblock.
675 * @ubi: UBI device description object
676 * @si: scanning information
677 * @pnum: physical eraseblock number to erase;
678 * @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown)
679 *
680 * This function erases physical eraseblock 'pnum', and writes the erase
681 * counter header to it. This function should only be used on UBI device
682 * initialization stages, when the EBA sub-system had not been yet initialized.
683 * This function returns zero in case of success and a negative error code in
684 * case of failure.
685 */
686int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
687 int pnum, int ec)
688{
689 int err;
690 struct ubi_ec_hdr *ec_hdr;
691
692 if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
693 /*
694 * Erase counter overflow. Upgrade UBI and use 64-bit
695 * erase counters internally.
696 */
697 ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
698 return -EINVAL;
699 }
700
701 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
702 if (!ec_hdr)
703 return -ENOMEM;
704
705 ec_hdr->ec = cpu_to_be64(ec);
706
707 err = ubi_io_sync_erase(ubi, pnum, 0);
708 if (err < 0)
709 goto out_free;
710
711 err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
712
713out_free:
714 kfree(ec_hdr);
715 return err;
716}
717
718/**
719 * ubi_scan_get_free_peb - get a free physical eraseblock.
720 * @ubi: UBI device description object
721 * @si: scanning information
722 *
723 * This function returns a free physical eraseblock. It is supposed to be
724 * called on the UBI initialization stages when the wear-leveling sub-system is
725 * not initialized yet. This function picks a physical eraseblocks from one of
726 * the lists, writes the EC header if it is needed, and removes it from the
727 * list.
728 *
729 * This function returns scanning physical eraseblock information in case of
730 * success and an error code in case of failure.
731 */
732struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
733 struct ubi_scan_info *si)
734{
735 int err = 0;
736 struct ubi_scan_leb *seb, *tmp_seb;
737
738 if (!list_empty(&si->free)) {
739 seb = list_entry(si->free.next, struct ubi_scan_leb, u.list);
740 list_del(&seb->u.list);
741 dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec);
742 return seb;
743 }
744
745 /*
746 * We try to erase the first physical eraseblock from the erase list
747 * and pick it if we succeed, or try to erase the next one if not. And
748 * so forth. We don't want to take care about bad eraseblocks here -
749 * they'll be handled later.
750 */
751 list_for_each_entry_safe(seb, tmp_seb, &si->erase, u.list) {
752 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
753 seb->ec = si->mean_ec;
754
755 err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1);
756 if (err)
757 continue;
758
759 seb->ec += 1;
760 list_del(&seb->u.list);
761 dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec);
762 return seb;
763 }
764
765 ubi_err("no free eraseblocks");
766 return ERR_PTR(-ENOSPC);
767}
768
769/**
770 * check_corruption - check the data area of PEB.
771 * @ubi: UBI device description object
772 * @vid_hrd: the (corrupted) VID header of this PEB
773 * @pnum: the physical eraseblock number to check
774 *
775 * This is a helper function which is used to distinguish between VID header
776 * corruptions caused by power cuts and other reasons. If the PEB contains only
777 * 0xFF bytes in the data area, the VID header is most probably corrupted
778 * because of a power cut (%0 is returned in this case). Otherwise, it was
779 * probably corrupted for some other reasons (%1 is returned in this case). A
780 * negative error code is returned if a read error occurred.
781 *
782 * If the corruption reason was a power cut, UBI can safely erase this PEB.
783 * Otherwise, it should preserve it to avoid possibly destroying important
784 * information.
785 */
786static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr,
787 int pnum)
788{
789 int err;
790
791 mutex_lock(&ubi->buf_mutex);
792 memset(ubi->peb_buf1, 0x00, ubi->leb_size);
793
794 err = ubi_io_read(ubi, ubi->peb_buf1, pnum, ubi->leb_start,
795 ubi->leb_size);
796 if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
797 /*
798 * Bit-flips or integrity errors while reading the data area.
799 * It is difficult to say for sure what type of corruption is
800 * this, but presumably a power cut happened while this PEB was
801 * erased, so it became unstable and corrupted, and should be
802 * erased.
803 */
804 err = 0;
805 goto out_unlock;
806 }
807
808 if (err)
809 goto out_unlock;
810
811 if (ubi_check_pattern(ubi->peb_buf1, 0xFF, ubi->leb_size))
812 goto out_unlock;
813
814 ubi_err("PEB %d contains corrupted VID header, and the data does not "
815 "contain all 0xFF, this may be a non-UBI PEB or a severe VID "
816 "header corruption which requires manual inspection", pnum);
817 ubi_dbg_dump_vid_hdr(vid_hdr);
818 dbg_msg("hexdump of PEB %d offset %d, length %d",
819 pnum, ubi->leb_start, ubi->leb_size);
820 ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
821 ubi->peb_buf1, ubi->leb_size, 1);
822 err = 1;
823
824out_unlock:
825 mutex_unlock(&ubi->buf_mutex);
826 return err;
827}
828
829/**
830 * process_eb - read, check UBI headers, and add them to scanning information.
831 * @ubi: UBI device description object
832 * @si: scanning information
833 * @pnum: the physical eraseblock number
834 *
835 * This function returns a zero if the physical eraseblock was successfully
836 * handled and a negative error code in case of failure.
837 */
838static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
839 int pnum)
840{
841 long long uninitialized_var(ec);
842 int err, bitflips = 0, vol_id, ec_err = 0;
843
844 dbg_bld("scan PEB %d", pnum);
845
846 /* Skip bad physical eraseblocks */
847 err = ubi_io_is_bad(ubi, pnum);
848 if (err < 0)
849 return err;
850 else if (err) {
851 /*
852 * FIXME: this is actually duty of the I/O sub-system to
853 * initialize this, but MTD does not provide enough
854 * information.
855 */
856 si->bad_peb_count += 1;
857 return 0;
858 }
859
860 err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
861 if (err < 0)
862 return err;
863 switch (err) {
864 case 0:
865 break;
866 case UBI_IO_BITFLIPS:
867 bitflips = 1;
868 break;
869 case UBI_IO_FF:
870 si->empty_peb_count += 1;
871 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 0,
872 &si->erase);
873 case UBI_IO_FF_BITFLIPS:
874 si->empty_peb_count += 1;
875 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, 1,
876 &si->erase);
877 case UBI_IO_BAD_HDR_EBADMSG:
878 case UBI_IO_BAD_HDR:
879 /*
880 * We have to also look at the VID header, possibly it is not
881 * corrupted. Set %bitflips flag in order to make this PEB be
882 * moved and EC be re-created.
883 */
884 ec_err = err;
885 ec = UBI_SCAN_UNKNOWN_EC;
886 bitflips = 1;
887 break;
888 default:
889 ubi_err("'ubi_io_read_ec_hdr()' returned unknown code %d", err);
890 return -EINVAL;
891 }
892
893 if (!ec_err) {
894 int image_seq;
895
896 /* Make sure UBI version is OK */
897 if (ech->version != UBI_VERSION) {
898 ubi_err("this UBI version is %d, image version is %d",
899 UBI_VERSION, (int)ech->version);
900 return -EINVAL;
901 }
902
903 ec = be64_to_cpu(ech->ec);
904 if (ec > UBI_MAX_ERASECOUNTER) {
905 /*
906 * Erase counter overflow. The EC headers have 64 bits
907 * reserved, but we anyway make use of only 31 bit
908 * values, as this seems to be enough for any existing
909 * flash. Upgrade UBI and use 64-bit erase counters
910 * internally.
911 */
912 ubi_err("erase counter overflow, max is %d",
913 UBI_MAX_ERASECOUNTER);
914 ubi_dbg_dump_ec_hdr(ech);
915 return -EINVAL;
916 }
917
918 /*
919 * Make sure that all PEBs have the same image sequence number.
920 * This allows us to detect situations when users flash UBI
921 * images incorrectly, so that the flash has the new UBI image
922 * and leftovers from the old one. This feature was added
923 * relatively recently, and the sequence number was always
924 * zero, because old UBI implementations always set it to zero.
925 * For this reasons, we do not panic if some PEBs have zero
926 * sequence number, while other PEBs have non-zero sequence
927 * number.
928 */
929 image_seq = be32_to_cpu(ech->image_seq);
930 if (!ubi->image_seq && image_seq)
931 ubi->image_seq = image_seq;
932 if (ubi->image_seq && image_seq &&
933 ubi->image_seq != image_seq) {
934 ubi_err("bad image sequence number %d in PEB %d, "
935 "expected %d", image_seq, pnum, ubi->image_seq);
936 ubi_dbg_dump_ec_hdr(ech);
937 return -EINVAL;
938 }
939 }
940
941 /* OK, we've done with the EC header, let's look at the VID header */
942
943 err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
944 if (err < 0)
945 return err;
946 switch (err) {
947 case 0:
948 break;
949 case UBI_IO_BITFLIPS:
950 bitflips = 1;
951 break;
952 case UBI_IO_BAD_HDR_EBADMSG:
953 if (ec_err == UBI_IO_BAD_HDR_EBADMSG)
954 /*
955 * Both EC and VID headers are corrupted and were read
956 * with data integrity error, probably this is a bad
957 * PEB, bit it is not marked as bad yet. This may also
958 * be a result of power cut during erasure.
959 */
960 si->maybe_bad_peb_count += 1;
961 case UBI_IO_BAD_HDR:
962 if (ec_err)
963 /*
964 * Both headers are corrupted. There is a possibility
965 * that this a valid UBI PEB which has corresponding
966 * LEB, but the headers are corrupted. However, it is
967 * impossible to distinguish it from a PEB which just
968 * contains garbage because of a power cut during erase
969 * operation. So we just schedule this PEB for erasure.
970 *
971 * Besides, in case of NOR flash, we deliberately
972 * corrupt both headers because NOR flash erasure is
973 * slow and can start from the end.
974 */
975 err = 0;
976 else
977 /*
978 * The EC was OK, but the VID header is corrupted. We
979 * have to check what is in the data area.
980 */
981 err = check_corruption(ubi, vidh, pnum);
982
983 if (err < 0)
984 return err;
985 else if (!err)
986 /* This corruption is caused by a power cut */
987 err = add_to_list(si, pnum, ec, 1, &si->erase);
988 else
989 /* This is an unexpected corruption */
990 err = add_corrupted(si, pnum, ec);
991 if (err)
992 return err;
993 goto adjust_mean_ec;
994 case UBI_IO_FF_BITFLIPS:
995 err = add_to_list(si, pnum, ec, 1, &si->erase);
996 if (err)
997 return err;
998 goto adjust_mean_ec;
999 case UBI_IO_FF:
1000 if (ec_err)
1001 err = add_to_list(si, pnum, ec, 1, &si->erase);
1002 else
1003 err = add_to_list(si, pnum, ec, 0, &si->free);
1004 if (err)
1005 return err;
1006 goto adjust_mean_ec;
1007 default:
1008 ubi_err("'ubi_io_read_vid_hdr()' returned unknown code %d",
1009 err);
1010 return -EINVAL;
1011 }
1012
1013 vol_id = be32_to_cpu(vidh->vol_id);
1014 if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
1015 int lnum = be32_to_cpu(vidh->lnum);
1016
1017 /* Unsupported internal volume */
1018 switch (vidh->compat) {
1019 case UBI_COMPAT_DELETE:
1020 ubi_msg("\"delete\" compatible internal volume %d:%d"
1021 " found, will remove it", vol_id, lnum);
1022 err = add_to_list(si, pnum, ec, 1, &si->erase);
1023 if (err)
1024 return err;
1025 return 0;
1026
1027 case UBI_COMPAT_RO:
1028 ubi_msg("read-only compatible internal volume %d:%d"
1029 " found, switch to read-only mode",
1030 vol_id, lnum);
1031 ubi->ro_mode = 1;
1032 break;
1033
1034 case UBI_COMPAT_PRESERVE:
1035 ubi_msg("\"preserve\" compatible internal volume %d:%d"
1036 " found", vol_id, lnum);
1037 err = add_to_list(si, pnum, ec, 0, &si->alien);
1038 if (err)
1039 return err;
1040 return 0;
1041
1042 case UBI_COMPAT_REJECT:
1043 ubi_err("incompatible internal volume %d:%d found",
1044 vol_id, lnum);
1045 return -EINVAL;
1046 }
1047 }
1048
1049 if (ec_err)
1050 ubi_warn("valid VID header but corrupted EC header at PEB %d",
1051 pnum);
1052 err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips);
1053 if (err)
1054 return err;
1055
1056adjust_mean_ec:
1057 if (!ec_err) {
1058 si->ec_sum += ec;
1059 si->ec_count += 1;
1060 if (ec > si->max_ec)
1061 si->max_ec = ec;
1062 if (ec < si->min_ec)
1063 si->min_ec = ec;
1064 }
1065
1066 return 0;
1067}
1068
1069/**
1070 * check_what_we_have - check what PEB were found by scanning.
1071 * @ubi: UBI device description object
1072 * @si: scanning information
1073 *
1074 * This is a helper function which takes a look what PEBs were found by
1075 * scanning, and decides whether the flash is empty and should be formatted and
1076 * whether there are too many corrupted PEBs and we should not attach this
1077 * MTD device. Returns zero if we should proceed with attaching the MTD device,
1078 * and %-EINVAL if we should not.
1079 */
1080static int check_what_we_have(struct ubi_device *ubi, struct ubi_scan_info *si)
1081{
1082 struct ubi_scan_leb *seb;
1083 int max_corr, peb_count;
1084
1085 peb_count = ubi->peb_count - si->bad_peb_count - si->alien_peb_count;
1086 max_corr = peb_count / 20 ?: 8;
1087
1088 /*
1089 * Few corrupted PEBs is not a problem and may be just a result of
1090 * unclean reboots. However, many of them may indicate some problems
1091 * with the flash HW or driver.
1092 */
1093 if (si->corr_peb_count) {
1094 ubi_err("%d PEBs are corrupted and preserved",
1095 si->corr_peb_count);
1096 printk(KERN_ERR "Corrupted PEBs are:");
1097 list_for_each_entry(seb, &si->corr, u.list)
1098 printk(KERN_CONT " %d", seb->pnum);
1099 printk(KERN_CONT "\n");
1100
1101 /*
1102 * If too many PEBs are corrupted, we refuse attaching,
1103 * otherwise, only print a warning.
1104 */
1105 if (si->corr_peb_count >= max_corr) {
1106 ubi_err("too many corrupted PEBs, refusing");
1107 return -EINVAL;
1108 }
1109 }
1110
1111 if (si->empty_peb_count + si->maybe_bad_peb_count == peb_count) {
1112 /*
1113 * All PEBs are empty, or almost all - a couple PEBs look like
1114 * they may be bad PEBs which were not marked as bad yet.
1115 *
1116 * This piece of code basically tries to distinguish between
1117 * the following situations:
1118 *
1119 * 1. Flash is empty, but there are few bad PEBs, which are not
1120 * marked as bad so far, and which were read with error. We
1121 * want to go ahead and format this flash. While formatting,
1122 * the faulty PEBs will probably be marked as bad.
1123 *
1124 * 2. Flash contains non-UBI data and we do not want to format
1125 * it and destroy possibly important information.
1126 */
1127 if (si->maybe_bad_peb_count <= 2) {
1128 si->is_empty = 1;
1129 ubi_msg("empty MTD device detected");
1130 get_random_bytes(&ubi->image_seq,
1131 sizeof(ubi->image_seq));
1132 } else {
1133 ubi_err("MTD device is not UBI-formatted and possibly "
1134 "contains non-UBI data - refusing it");
1135 return -EINVAL;
1136 }
1137
1138 }
1139
1140 return 0;
1141}
1142
1143/**
1144 * ubi_scan - scan an MTD device.
1145 * @ubi: UBI device description object
1146 *
1147 * This function does full scanning of an MTD device and returns complete
1148 * information about it. In case of failure, an error code is returned.
1149 */
1150struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
1151{
1152 int err, pnum;
1153 struct rb_node *rb1, *rb2;
1154 struct ubi_scan_volume *sv;
1155 struct ubi_scan_leb *seb;
1156 struct ubi_scan_info *si;
1157
1158 si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL);
1159 if (!si)
1160 return ERR_PTR(-ENOMEM);
1161
1162 INIT_LIST_HEAD(&si->corr);
1163 INIT_LIST_HEAD(&si->free);
1164 INIT_LIST_HEAD(&si->erase);
1165 INIT_LIST_HEAD(&si->alien);
1166 si->volumes = RB_ROOT;
1167
1168 err = -ENOMEM;
1169 si->scan_leb_slab = kmem_cache_create("ubi_scan_leb_slab",
1170 sizeof(struct ubi_scan_leb),
1171 0, 0, NULL);
1172 if (!si->scan_leb_slab)
1173 goto out_si;
1174
1175 ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1176 if (!ech)
1177 goto out_slab;
1178
1179 vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
1180 if (!vidh)
1181 goto out_ech;
1182
1183 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1184 cond_resched();
1185
1186 dbg_gen("process PEB %d", pnum);
1187 err = process_eb(ubi, si, pnum);
1188 if (err < 0)
1189 goto out_vidh;
1190 }
1191
1192 dbg_msg("scanning is finished");
1193
1194 /* Calculate mean erase counter */
1195 if (si->ec_count)
1196 si->mean_ec = div_u64(si->ec_sum, si->ec_count);
1197
1198 err = check_what_we_have(ubi, si);
1199 if (err)
1200 goto out_vidh;
1201
1202 /*
1203 * In case of unknown erase counter we use the mean erase counter
1204 * value.
1205 */
1206 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1207 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1208 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1209 seb->ec = si->mean_ec;
1210 }
1211
1212 list_for_each_entry(seb, &si->free, u.list) {
1213 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1214 seb->ec = si->mean_ec;
1215 }
1216
1217 list_for_each_entry(seb, &si->corr, u.list)
1218 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1219 seb->ec = si->mean_ec;
1220
1221 list_for_each_entry(seb, &si->erase, u.list)
1222 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1223 seb->ec = si->mean_ec;
1224
1225 err = paranoid_check_si(ubi, si);
1226 if (err)
1227 goto out_vidh;
1228
1229 ubi_free_vid_hdr(ubi, vidh);
1230 kfree(ech);
1231
1232 return si;
1233
1234out_vidh:
1235 ubi_free_vid_hdr(ubi, vidh);
1236out_ech:
1237 kfree(ech);
1238out_slab:
1239 kmem_cache_destroy(si->scan_leb_slab);
1240out_si:
1241 ubi_scan_destroy_si(si);
1242 return ERR_PTR(err);
1243}
1244
1245/**
1246 * destroy_sv - free the scanning volume information
1247 * @sv: scanning volume information
1248 * @si: scanning information
1249 *
1250 * This function destroys the volume RB-tree (@sv->root) and the scanning
1251 * volume information.
1252 */
1253static void destroy_sv(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
1254{
1255 struct ubi_scan_leb *seb;
1256 struct rb_node *this = sv->root.rb_node;
1257
1258 while (this) {
1259 if (this->rb_left)
1260 this = this->rb_left;
1261 else if (this->rb_right)
1262 this = this->rb_right;
1263 else {
1264 seb = rb_entry(this, struct ubi_scan_leb, u.rb);
1265 this = rb_parent(this);
1266 if (this) {
1267 if (this->rb_left == &seb->u.rb)
1268 this->rb_left = NULL;
1269 else
1270 this->rb_right = NULL;
1271 }
1272
1273 kmem_cache_free(si->scan_leb_slab, seb);
1274 }
1275 }
1276 kfree(sv);
1277}
1278
1279/**
1280 * ubi_scan_destroy_si - destroy scanning information.
1281 * @si: scanning information
1282 */
1283void ubi_scan_destroy_si(struct ubi_scan_info *si)
1284{
1285 struct ubi_scan_leb *seb, *seb_tmp;
1286 struct ubi_scan_volume *sv;
1287 struct rb_node *rb;
1288
1289 list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {
1290 list_del(&seb->u.list);
1291 kmem_cache_free(si->scan_leb_slab, seb);
1292 }
1293 list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
1294 list_del(&seb->u.list);
1295 kmem_cache_free(si->scan_leb_slab, seb);
1296 }
1297 list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
1298 list_del(&seb->u.list);
1299 kmem_cache_free(si->scan_leb_slab, seb);
1300 }
1301 list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
1302 list_del(&seb->u.list);
1303 kmem_cache_free(si->scan_leb_slab, seb);
1304 }
1305
1306 /* Destroy the volume RB-tree */
1307 rb = si->volumes.rb_node;
1308 while (rb) {
1309 if (rb->rb_left)
1310 rb = rb->rb_left;
1311 else if (rb->rb_right)
1312 rb = rb->rb_right;
1313 else {
1314 sv = rb_entry(rb, struct ubi_scan_volume, rb);
1315
1316 rb = rb_parent(rb);
1317 if (rb) {
1318 if (rb->rb_left == &sv->rb)
1319 rb->rb_left = NULL;
1320 else
1321 rb->rb_right = NULL;
1322 }
1323
1324 destroy_sv(si, sv);
1325 }
1326 }
1327
1328 kmem_cache_destroy(si->scan_leb_slab);
1329 kfree(si);
1330}
1331
1332#ifdef CONFIG_MTD_UBI_DEBUG
1333
1334/**
1335 * paranoid_check_si - check the scanning information.
1336 * @ubi: UBI device description object
1337 * @si: scanning information
1338 *
1339 * This function returns zero if the scanning information is all right, and a
1340 * negative error code if not or if an error occurred.
1341 */
1342static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
1343{
1344 int pnum, err, vols_found = 0;
1345 struct rb_node *rb1, *rb2;
1346 struct ubi_scan_volume *sv;
1347 struct ubi_scan_leb *seb, *last_seb;
1348 uint8_t *buf;
1349
1350 if (!ubi->dbg->chk_gen)
1351 return 0;
1352
1353 /*
1354 * At first, check that scanning information is OK.
1355 */
1356 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1357 int leb_count = 0;
1358
1359 cond_resched();
1360
1361 vols_found += 1;
1362
1363 if (si->is_empty) {
1364 ubi_err("bad is_empty flag");
1365 goto bad_sv;
1366 }
1367
1368 if (sv->vol_id < 0 || sv->highest_lnum < 0 ||
1369 sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 ||
1370 sv->data_pad < 0 || sv->last_data_size < 0) {
1371 ubi_err("negative values");
1372 goto bad_sv;
1373 }
1374
1375 if (sv->vol_id >= UBI_MAX_VOLUMES &&
1376 sv->vol_id < UBI_INTERNAL_VOL_START) {
1377 ubi_err("bad vol_id");
1378 goto bad_sv;
1379 }
1380
1381 if (sv->vol_id > si->highest_vol_id) {
1382 ubi_err("highest_vol_id is %d, but vol_id %d is there",
1383 si->highest_vol_id, sv->vol_id);
1384 goto out;
1385 }
1386
1387 if (sv->vol_type != UBI_DYNAMIC_VOLUME &&
1388 sv->vol_type != UBI_STATIC_VOLUME) {
1389 ubi_err("bad vol_type");
1390 goto bad_sv;
1391 }
1392
1393 if (sv->data_pad > ubi->leb_size / 2) {
1394 ubi_err("bad data_pad");
1395 goto bad_sv;
1396 }
1397
1398 last_seb = NULL;
1399 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1400 cond_resched();
1401
1402 last_seb = seb;
1403 leb_count += 1;
1404
1405 if (seb->pnum < 0 || seb->ec < 0) {
1406 ubi_err("negative values");
1407 goto bad_seb;
1408 }
1409
1410 if (seb->ec < si->min_ec) {
1411 ubi_err("bad si->min_ec (%d), %d found",
1412 si->min_ec, seb->ec);
1413 goto bad_seb;
1414 }
1415
1416 if (seb->ec > si->max_ec) {
1417 ubi_err("bad si->max_ec (%d), %d found",
1418 si->max_ec, seb->ec);
1419 goto bad_seb;
1420 }
1421
1422 if (seb->pnum >= ubi->peb_count) {
1423 ubi_err("too high PEB number %d, total PEBs %d",
1424 seb->pnum, ubi->peb_count);
1425 goto bad_seb;
1426 }
1427
1428 if (sv->vol_type == UBI_STATIC_VOLUME) {
1429 if (seb->lnum >= sv->used_ebs) {
1430 ubi_err("bad lnum or used_ebs");
1431 goto bad_seb;
1432 }
1433 } else {
1434 if (sv->used_ebs != 0) {
1435 ubi_err("non-zero used_ebs");
1436 goto bad_seb;
1437 }
1438 }
1439
1440 if (seb->lnum > sv->highest_lnum) {
1441 ubi_err("incorrect highest_lnum or lnum");
1442 goto bad_seb;
1443 }
1444 }
1445
1446 if (sv->leb_count != leb_count) {
1447 ubi_err("bad leb_count, %d objects in the tree",
1448 leb_count);
1449 goto bad_sv;
1450 }
1451
1452 if (!last_seb)
1453 continue;
1454
1455 seb = last_seb;
1456
1457 if (seb->lnum != sv->highest_lnum) {
1458 ubi_err("bad highest_lnum");
1459 goto bad_seb;
1460 }
1461 }
1462
1463 if (vols_found != si->vols_found) {
1464 ubi_err("bad si->vols_found %d, should be %d",
1465 si->vols_found, vols_found);
1466 goto out;
1467 }
1468
1469 /* Check that scanning information is correct */
1470 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1471 last_seb = NULL;
1472 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1473 int vol_type;
1474
1475 cond_resched();
1476
1477 last_seb = seb;
1478
1479 err = ubi_io_read_vid_hdr(ubi, seb->pnum, vidh, 1);
1480 if (err && err != UBI_IO_BITFLIPS) {
1481 ubi_err("VID header is not OK (%d)", err);
1482 if (err > 0)
1483 err = -EIO;
1484 return err;
1485 }
1486
1487 vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1488 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1489 if (sv->vol_type != vol_type) {
1490 ubi_err("bad vol_type");
1491 goto bad_vid_hdr;
1492 }
1493
1494 if (seb->sqnum != be64_to_cpu(vidh->sqnum)) {
1495 ubi_err("bad sqnum %llu", seb->sqnum);
1496 goto bad_vid_hdr;
1497 }
1498
1499 if (sv->vol_id != be32_to_cpu(vidh->vol_id)) {
1500 ubi_err("bad vol_id %d", sv->vol_id);
1501 goto bad_vid_hdr;
1502 }
1503
1504 if (sv->compat != vidh->compat) {
1505 ubi_err("bad compat %d", vidh->compat);
1506 goto bad_vid_hdr;
1507 }
1508
1509 if (seb->lnum != be32_to_cpu(vidh->lnum)) {
1510 ubi_err("bad lnum %d", seb->lnum);
1511 goto bad_vid_hdr;
1512 }
1513
1514 if (sv->used_ebs != be32_to_cpu(vidh->used_ebs)) {
1515 ubi_err("bad used_ebs %d", sv->used_ebs);
1516 goto bad_vid_hdr;
1517 }
1518
1519 if (sv->data_pad != be32_to_cpu(vidh->data_pad)) {
1520 ubi_err("bad data_pad %d", sv->data_pad);
1521 goto bad_vid_hdr;
1522 }
1523 }
1524
1525 if (!last_seb)
1526 continue;
1527
1528 if (sv->highest_lnum != be32_to_cpu(vidh->lnum)) {
1529 ubi_err("bad highest_lnum %d", sv->highest_lnum);
1530 goto bad_vid_hdr;
1531 }
1532
1533 if (sv->last_data_size != be32_to_cpu(vidh->data_size)) {
1534 ubi_err("bad last_data_size %d", sv->last_data_size);
1535 goto bad_vid_hdr;
1536 }
1537 }
1538
1539 /*
1540 * Make sure that all the physical eraseblocks are in one of the lists
1541 * or trees.
1542 */
1543 buf = kzalloc(ubi->peb_count, GFP_KERNEL);
1544 if (!buf)
1545 return -ENOMEM;
1546
1547 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1548 err = ubi_io_is_bad(ubi, pnum);
1549 if (err < 0) {
1550 kfree(buf);
1551 return err;
1552 } else if (err)
1553 buf[pnum] = 1;
1554 }
1555
1556 ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb)
1557 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1558 buf[seb->pnum] = 1;
1559
1560 list_for_each_entry(seb, &si->free, u.list)
1561 buf[seb->pnum] = 1;
1562
1563 list_for_each_entry(seb, &si->corr, u.list)
1564 buf[seb->pnum] = 1;
1565
1566 list_for_each_entry(seb, &si->erase, u.list)
1567 buf[seb->pnum] = 1;
1568
1569 list_for_each_entry(seb, &si->alien, u.list)
1570 buf[seb->pnum] = 1;
1571
1572 err = 0;
1573 for (pnum = 0; pnum < ubi->peb_count; pnum++)
1574 if (!buf[pnum]) {
1575 ubi_err("PEB %d is not referred", pnum);
1576 err = 1;
1577 }
1578
1579 kfree(buf);
1580 if (err)
1581 goto out;
1582 return 0;
1583
1584bad_seb:
1585 ubi_err("bad scanning information about LEB %d", seb->lnum);
1586 ubi_dbg_dump_seb(seb, 0);
1587 ubi_dbg_dump_sv(sv);
1588 goto out;
1589
1590bad_sv:
1591 ubi_err("bad scanning information about volume %d", sv->vol_id);
1592 ubi_dbg_dump_sv(sv);
1593 goto out;
1594
1595bad_vid_hdr:
1596 ubi_err("bad scanning information about volume %d", sv->vol_id);
1597 ubi_dbg_dump_sv(sv);
1598 ubi_dbg_dump_vid_hdr(vidh);
1599
1600out:
1601 ubi_dbg_dump_stack();
1602 return -EINVAL;
1603}
1604
1605#endif /* CONFIG_MTD_UBI_DEBUG */