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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 attaching sub-system.
23 *
24 * This sub-system is responsible for attaching MTD devices and it also
25 * implements flash media scanning.
26 *
27 * The attaching information is represented by a &struct ubi_attach_info'
28 * object. Information about volumes is represented by &struct ubi_ainf_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 * Logical eraseblocks are represented by &struct ubi_ainf_peb objects. These
33 * objects are kept in per-volume RB-trees with the root at the corresponding
34 * &struct ubi_ainf_volume object. To put it differently, we keep an RB-tree of
35 * per-volume objects and each of these objects is the root of RB-tree of
36 * per-LEB 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
55 * cases - we may lose only the data which were being written to the media just
56 * before the power cut happened, and the upper layers (e.g., UBIFS) are
57 * supposed to 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 * attaching, 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 (in case of attaching by
71 * scanning). UBI assumes corruption type 2 if the VID header is corrupted and
72 * the data area does not contain all 0xFFs, and there were no bit-flips or
73 * integrity errors (e.g., ECC errors in case of NAND) while reading the data
74 * area. Otherwise UBI assumes corruption type 1. So the decision criteria
75 * are as follows.
76 * o If the data area contains only 0xFFs, there are no data, and it is safe
77 * to just erase this PEB - this is corruption type 1.
78 * o If the data area has bit-flips or data integrity errors (ECC errors on
79 * NAND), it is probably a PEB which was being erased when power cut
80 * happened, so this is corruption type 1. However, this is just a guess,
81 * which might be wrong.
82 * o Otherwise this is corruption type 2.
83 */
84
85#include <linux/err.h>
86#include <linux/slab.h>
87#include <linux/crc32.h>
88#include <linux/math64.h>
89#include <linux/random.h>
90#include "ubi.h"
91
92static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai);
93
94#define AV_FIND BIT(0)
95#define AV_ADD BIT(1)
96#define AV_FIND_OR_ADD (AV_FIND | AV_ADD)
97
98/**
99 * find_or_add_av - internal function to find a volume, add a volume or do
100 * both (find and add if missing).
101 * @ai: attaching information
102 * @vol_id: the requested volume ID
103 * @flags: a combination of the %AV_FIND and %AV_ADD flags describing the
104 * expected operation. If only %AV_ADD is set, -EEXIST is returned
105 * if the volume already exists. If only %AV_FIND is set, NULL is
106 * returned if the volume does not exist. And if both flags are
107 * set, the helper first tries to find an existing volume, and if
108 * it does not exist it creates a new one.
109 * @created: in value used to inform the caller whether it"s a newly created
110 * volume or not.
111 *
112 * This function returns a pointer to a volume description or an ERR_PTR if
113 * the operation failed. It can also return NULL if only %AV_FIND is set and
114 * the volume does not exist.
115 */
116static struct ubi_ainf_volume *find_or_add_av(struct ubi_attach_info *ai,
117 int vol_id, unsigned int flags,
118 bool *created)
119{
120 struct ubi_ainf_volume *av;
121 struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
122
123 /* Walk the volume RB-tree to look if this volume is already present */
124 while (*p) {
125 parent = *p;
126 av = rb_entry(parent, struct ubi_ainf_volume, rb);
127
128 if (vol_id == av->vol_id) {
129 *created = false;
130
131 if (!(flags & AV_FIND))
132 return ERR_PTR(-EEXIST);
133
134 return av;
135 }
136
137 if (vol_id > av->vol_id)
138 p = &(*p)->rb_left;
139 else
140 p = &(*p)->rb_right;
141 }
142
143 if (!(flags & AV_ADD))
144 return NULL;
145
146 /* The volume is absent - add it */
147 av = kzalloc(sizeof(*av), GFP_KERNEL);
148 if (!av)
149 return ERR_PTR(-ENOMEM);
150
151 av->vol_id = vol_id;
152
153 if (vol_id > ai->highest_vol_id)
154 ai->highest_vol_id = vol_id;
155
156 rb_link_node(&av->rb, parent, p);
157 rb_insert_color(&av->rb, &ai->volumes);
158 ai->vols_found += 1;
159 *created = true;
160 dbg_bld("added volume %d", vol_id);
161 return av;
162}
163
164/**
165 * ubi_find_or_add_av - search for a volume in the attaching information and
166 * add one if it does not exist.
167 * @ai: attaching information
168 * @vol_id: the requested volume ID
169 * @created: whether the volume has been created or not
170 *
171 * This function returns a pointer to the new volume description or an
172 * ERR_PTR if the operation failed.
173 */
174static struct ubi_ainf_volume *ubi_find_or_add_av(struct ubi_attach_info *ai,
175 int vol_id, bool *created)
176{
177 return find_or_add_av(ai, vol_id, AV_FIND_OR_ADD, created);
178}
179
180/**
181 * ubi_alloc_aeb - allocate an aeb element
182 * @ai: attaching information
183 * @pnum: physical eraseblock number
184 * @ec: erase counter of the physical eraseblock
185 *
186 * Allocate an aeb object and initialize the pnum and ec information.
187 * vol_id and lnum are set to UBI_UNKNOWN, and the other fields are
188 * initialized to zero.
189 * Note that the element is not added in any list or RB tree.
190 */
191struct ubi_ainf_peb *ubi_alloc_aeb(struct ubi_attach_info *ai, int pnum,
192 int ec)
193{
194 struct ubi_ainf_peb *aeb;
195
196 aeb = kmem_cache_zalloc(ai->aeb_slab_cache, GFP_KERNEL);
197 if (!aeb)
198 return NULL;
199
200 aeb->pnum = pnum;
201 aeb->ec = ec;
202 aeb->vol_id = UBI_UNKNOWN;
203 aeb->lnum = UBI_UNKNOWN;
204
205 return aeb;
206}
207
208/**
209 * ubi_free_aeb - free an aeb element
210 * @ai: attaching information
211 * @aeb: the element to free
212 *
213 * Free an aeb object. The caller must have removed the element from any list
214 * or RB tree.
215 */
216void ubi_free_aeb(struct ubi_attach_info *ai, struct ubi_ainf_peb *aeb)
217{
218 kmem_cache_free(ai->aeb_slab_cache, aeb);
219}
220
221/**
222 * add_to_list - add physical eraseblock to a list.
223 * @ai: attaching information
224 * @pnum: physical eraseblock number to add
225 * @vol_id: the last used volume id for the PEB
226 * @lnum: the last used LEB number for the PEB
227 * @ec: erase counter of the physical eraseblock
228 * @to_head: if not zero, add to the head of the list
229 * @list: the list to add to
230 *
231 * This function allocates a 'struct ubi_ainf_peb' object for physical
232 * eraseblock @pnum and adds it to the "free", "erase", or "alien" lists.
233 * It stores the @lnum and @vol_id alongside, which can both be
234 * %UBI_UNKNOWN if they are not available, not readable, or not assigned.
235 * If @to_head is not zero, PEB will be added to the head of the list, which
236 * basically means it will be processed first later. E.g., we add corrupted
237 * PEBs (corrupted due to power cuts) to the head of the erase list to make
238 * sure we erase them first and get rid of corruptions ASAP. This function
239 * returns zero in case of success and a negative error code in case of
240 * failure.
241 */
242static int add_to_list(struct ubi_attach_info *ai, int pnum, int vol_id,
243 int lnum, int ec, int to_head, struct list_head *list)
244{
245 struct ubi_ainf_peb *aeb;
246
247 if (list == &ai->free) {
248 dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
249 } else if (list == &ai->erase) {
250 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
251 } else if (list == &ai->alien) {
252 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
253 ai->alien_peb_count += 1;
254 } else
255 BUG();
256
257 aeb = ubi_alloc_aeb(ai, pnum, ec);
258 if (!aeb)
259 return -ENOMEM;
260
261 aeb->vol_id = vol_id;
262 aeb->lnum = lnum;
263 if (to_head)
264 list_add(&aeb->u.list, list);
265 else
266 list_add_tail(&aeb->u.list, list);
267 return 0;
268}
269
270/**
271 * add_corrupted - add a corrupted physical eraseblock.
272 * @ai: attaching information
273 * @pnum: physical eraseblock number to add
274 * @ec: erase counter of the physical eraseblock
275 *
276 * This function allocates a 'struct ubi_ainf_peb' object for a corrupted
277 * physical eraseblock @pnum and adds it to the 'corr' list. The corruption
278 * was presumably not caused by a power cut. Returns zero in case of success
279 * and a negative error code in case of failure.
280 */
281static int add_corrupted(struct ubi_attach_info *ai, int pnum, int ec)
282{
283 struct ubi_ainf_peb *aeb;
284
285 dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
286
287 aeb = ubi_alloc_aeb(ai, pnum, ec);
288 if (!aeb)
289 return -ENOMEM;
290
291 ai->corr_peb_count += 1;
292 list_add(&aeb->u.list, &ai->corr);
293 return 0;
294}
295
296/**
297 * add_fastmap - add a Fastmap related physical eraseblock.
298 * @ai: attaching information
299 * @pnum: physical eraseblock number the VID header came from
300 * @vid_hdr: the volume identifier header
301 * @ec: erase counter of the physical eraseblock
302 *
303 * This function allocates a 'struct ubi_ainf_peb' object for a Fastamp
304 * physical eraseblock @pnum and adds it to the 'fastmap' list.
305 * Such blocks can be Fastmap super and data blocks from both the most
306 * recent Fastmap we're attaching from or from old Fastmaps which will
307 * be erased.
308 */
309static int add_fastmap(struct ubi_attach_info *ai, int pnum,
310 struct ubi_vid_hdr *vid_hdr, int ec)
311{
312 struct ubi_ainf_peb *aeb;
313
314 aeb = ubi_alloc_aeb(ai, pnum, ec);
315 if (!aeb)
316 return -ENOMEM;
317
318 aeb->vol_id = be32_to_cpu(vid_hdr->vol_id);
319 aeb->sqnum = be64_to_cpu(vid_hdr->sqnum);
320 list_add(&aeb->u.list, &ai->fastmap);
321
322 dbg_bld("add to fastmap list: PEB %d, vol_id %d, sqnum: %llu", pnum,
323 aeb->vol_id, aeb->sqnum);
324
325 return 0;
326}
327
328/**
329 * validate_vid_hdr - check volume identifier header.
330 * @ubi: UBI device description object
331 * @vid_hdr: the volume identifier header to check
332 * @av: information about the volume this logical eraseblock belongs to
333 * @pnum: physical eraseblock number the VID header came from
334 *
335 * This function checks that data stored in @vid_hdr is consistent. Returns
336 * non-zero if an inconsistency was found and zero if not.
337 *
338 * Note, UBI does sanity check of everything it reads from the flash media.
339 * Most of the checks are done in the I/O sub-system. Here we check that the
340 * information in the VID header is consistent to the information in other VID
341 * headers of the same volume.
342 */
343static int validate_vid_hdr(const struct ubi_device *ubi,
344 const struct ubi_vid_hdr *vid_hdr,
345 const struct ubi_ainf_volume *av, int pnum)
346{
347 int vol_type = vid_hdr->vol_type;
348 int vol_id = be32_to_cpu(vid_hdr->vol_id);
349 int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
350 int data_pad = be32_to_cpu(vid_hdr->data_pad);
351
352 if (av->leb_count != 0) {
353 int av_vol_type;
354
355 /*
356 * This is not the first logical eraseblock belonging to this
357 * volume. Ensure that the data in its VID header is consistent
358 * to the data in previous logical eraseblock headers.
359 */
360
361 if (vol_id != av->vol_id) {
362 ubi_err(ubi, "inconsistent vol_id");
363 goto bad;
364 }
365
366 if (av->vol_type == UBI_STATIC_VOLUME)
367 av_vol_type = UBI_VID_STATIC;
368 else
369 av_vol_type = UBI_VID_DYNAMIC;
370
371 if (vol_type != av_vol_type) {
372 ubi_err(ubi, "inconsistent vol_type");
373 goto bad;
374 }
375
376 if (used_ebs != av->used_ebs) {
377 ubi_err(ubi, "inconsistent used_ebs");
378 goto bad;
379 }
380
381 if (data_pad != av->data_pad) {
382 ubi_err(ubi, "inconsistent data_pad");
383 goto bad;
384 }
385 }
386
387 return 0;
388
389bad:
390 ubi_err(ubi, "inconsistent VID header at PEB %d", pnum);
391 ubi_dump_vid_hdr(vid_hdr);
392 ubi_dump_av(av);
393 return -EINVAL;
394}
395
396/**
397 * add_volume - add volume to the attaching information.
398 * @ai: attaching information
399 * @vol_id: ID of the volume to add
400 * @pnum: physical eraseblock number
401 * @vid_hdr: volume identifier header
402 *
403 * If the volume corresponding to the @vid_hdr logical eraseblock is already
404 * present in the attaching information, this function does nothing. Otherwise
405 * it adds corresponding volume to the attaching information. Returns a pointer
406 * to the allocated "av" object in case of success and a negative error code in
407 * case of failure.
408 */
409static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai,
410 int vol_id, int pnum,
411 const struct ubi_vid_hdr *vid_hdr)
412{
413 struct ubi_ainf_volume *av;
414 bool created;
415
416 ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
417
418 av = ubi_find_or_add_av(ai, vol_id, &created);
419 if (IS_ERR(av) || !created)
420 return av;
421
422 av->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
423 av->data_pad = be32_to_cpu(vid_hdr->data_pad);
424 av->compat = vid_hdr->compat;
425 av->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
426 : UBI_STATIC_VOLUME;
427
428 return av;
429}
430
431/**
432 * ubi_compare_lebs - find out which logical eraseblock is newer.
433 * @ubi: UBI device description object
434 * @aeb: first logical eraseblock to compare
435 * @pnum: physical eraseblock number of the second logical eraseblock to
436 * compare
437 * @vid_hdr: volume identifier header of the second logical eraseblock
438 *
439 * This function compares 2 copies of a LEB and informs which one is newer. In
440 * case of success this function returns a positive value, in case of failure, a
441 * negative error code is returned. The success return codes use the following
442 * bits:
443 * o bit 0 is cleared: the first PEB (described by @aeb) is newer than the
444 * second PEB (described by @pnum and @vid_hdr);
445 * o bit 0 is set: the second PEB is newer;
446 * o bit 1 is cleared: no bit-flips were detected in the newer LEB;
447 * o bit 1 is set: bit-flips were detected in the newer LEB;
448 * o bit 2 is cleared: the older LEB is not corrupted;
449 * o bit 2 is set: the older LEB is corrupted.
450 */
451int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
452 int pnum, const struct ubi_vid_hdr *vid_hdr)
453{
454 int len, err, second_is_newer, bitflips = 0, corrupted = 0;
455 uint32_t data_crc, crc;
456 struct ubi_vid_io_buf *vidb = NULL;
457 unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
458
459 if (sqnum2 == aeb->sqnum) {
460 /*
461 * This must be a really ancient UBI image which has been
462 * created before sequence numbers support has been added. At
463 * that times we used 32-bit LEB versions stored in logical
464 * eraseblocks. That was before UBI got into mainline. We do not
465 * support these images anymore. Well, those images still work,
466 * but only if no unclean reboots happened.
467 */
468 ubi_err(ubi, "unsupported on-flash UBI format");
469 return -EINVAL;
470 }
471
472 /* Obviously the LEB with lower sequence counter is older */
473 second_is_newer = (sqnum2 > aeb->sqnum);
474
475 /*
476 * Now we know which copy is newer. If the copy flag of the PEB with
477 * newer version is not set, then we just return, otherwise we have to
478 * check data CRC. For the second PEB we already have the VID header,
479 * for the first one - we'll need to re-read it from flash.
480 *
481 * Note: this may be optimized so that we wouldn't read twice.
482 */
483
484 if (second_is_newer) {
485 if (!vid_hdr->copy_flag) {
486 /* It is not a copy, so it is newer */
487 dbg_bld("second PEB %d is newer, copy_flag is unset",
488 pnum);
489 return 1;
490 }
491 } else {
492 if (!aeb->copy_flag) {
493 /* It is not a copy, so it is newer */
494 dbg_bld("first PEB %d is newer, copy_flag is unset",
495 pnum);
496 return bitflips << 1;
497 }
498
499 vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
500 if (!vidb)
501 return -ENOMEM;
502
503 pnum = aeb->pnum;
504 err = ubi_io_read_vid_hdr(ubi, pnum, vidb, 0);
505 if (err) {
506 if (err == UBI_IO_BITFLIPS)
507 bitflips = 1;
508 else {
509 ubi_err(ubi, "VID of PEB %d header is bad, but it was OK earlier, err %d",
510 pnum, err);
511 if (err > 0)
512 err = -EIO;
513
514 goto out_free_vidh;
515 }
516 }
517
518 vid_hdr = ubi_get_vid_hdr(vidb);
519 }
520
521 /* Read the data of the copy and check the CRC */
522
523 len = be32_to_cpu(vid_hdr->data_size);
524
525 mutex_lock(&ubi->buf_mutex);
526 err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, len);
527 if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
528 goto out_unlock;
529
530 data_crc = be32_to_cpu(vid_hdr->data_crc);
531 crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, len);
532 if (crc != data_crc) {
533 dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
534 pnum, crc, data_crc);
535 corrupted = 1;
536 bitflips = 0;
537 second_is_newer = !second_is_newer;
538 } else {
539 dbg_bld("PEB %d CRC is OK", pnum);
540 bitflips |= !!err;
541 }
542 mutex_unlock(&ubi->buf_mutex);
543
544 ubi_free_vid_buf(vidb);
545
546 if (second_is_newer)
547 dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
548 else
549 dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
550
551 return second_is_newer | (bitflips << 1) | (corrupted << 2);
552
553out_unlock:
554 mutex_unlock(&ubi->buf_mutex);
555out_free_vidh:
556 ubi_free_vid_buf(vidb);
557 return err;
558}
559
560/**
561 * ubi_add_to_av - add used physical eraseblock to the attaching information.
562 * @ubi: UBI device description object
563 * @ai: attaching information
564 * @pnum: the physical eraseblock number
565 * @ec: erase counter
566 * @vid_hdr: the volume identifier header
567 * @bitflips: if bit-flips were detected when this physical eraseblock was read
568 *
569 * This function adds information about a used physical eraseblock to the
570 * 'used' tree of the corresponding volume. The function is rather complex
571 * because it has to handle cases when this is not the first physical
572 * eraseblock belonging to the same logical eraseblock, and the newer one has
573 * to be picked, while the older one has to be dropped. This function returns
574 * zero in case of success and a negative error code in case of failure.
575 */
576int ubi_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
577 int ec, const struct ubi_vid_hdr *vid_hdr, int bitflips)
578{
579 int err, vol_id, lnum;
580 unsigned long long sqnum;
581 struct ubi_ainf_volume *av;
582 struct ubi_ainf_peb *aeb;
583 struct rb_node **p, *parent = NULL;
584
585 vol_id = be32_to_cpu(vid_hdr->vol_id);
586 lnum = be32_to_cpu(vid_hdr->lnum);
587 sqnum = be64_to_cpu(vid_hdr->sqnum);
588
589 dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
590 pnum, vol_id, lnum, ec, sqnum, bitflips);
591
592 av = add_volume(ai, vol_id, pnum, vid_hdr);
593 if (IS_ERR(av))
594 return PTR_ERR(av);
595
596 if (ai->max_sqnum < sqnum)
597 ai->max_sqnum = sqnum;
598
599 /*
600 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
601 * if this is the first instance of this logical eraseblock or not.
602 */
603 p = &av->root.rb_node;
604 while (*p) {
605 int cmp_res;
606
607 parent = *p;
608 aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
609 if (lnum != aeb->lnum) {
610 if (lnum < aeb->lnum)
611 p = &(*p)->rb_left;
612 else
613 p = &(*p)->rb_right;
614 continue;
615 }
616
617 /*
618 * There is already a physical eraseblock describing the same
619 * logical eraseblock present.
620 */
621
622 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, EC %d",
623 aeb->pnum, aeb->sqnum, aeb->ec);
624
625 /*
626 * Make sure that the logical eraseblocks have different
627 * sequence numbers. Otherwise the image is bad.
628 *
629 * However, if the sequence number is zero, we assume it must
630 * be an ancient UBI image from the era when UBI did not have
631 * sequence numbers. We still can attach these images, unless
632 * there is a need to distinguish between old and new
633 * eraseblocks, in which case we'll refuse the image in
634 * 'ubi_compare_lebs()'. In other words, we attach old clean
635 * images, but refuse attaching old images with duplicated
636 * logical eraseblocks because there was an unclean reboot.
637 */
638 if (aeb->sqnum == sqnum && sqnum != 0) {
639 ubi_err(ubi, "two LEBs with same sequence number %llu",
640 sqnum);
641 ubi_dump_aeb(aeb, 0);
642 ubi_dump_vid_hdr(vid_hdr);
643 return -EINVAL;
644 }
645
646 /*
647 * Now we have to drop the older one and preserve the newer
648 * one.
649 */
650 cmp_res = ubi_compare_lebs(ubi, aeb, pnum, vid_hdr);
651 if (cmp_res < 0)
652 return cmp_res;
653
654 if (cmp_res & 1) {
655 /*
656 * This logical eraseblock is newer than the one
657 * found earlier.
658 */
659 err = validate_vid_hdr(ubi, vid_hdr, av, pnum);
660 if (err)
661 return err;
662
663 err = add_to_list(ai, aeb->pnum, aeb->vol_id,
664 aeb->lnum, aeb->ec, cmp_res & 4,
665 &ai->erase);
666 if (err)
667 return err;
668
669 aeb->ec = ec;
670 aeb->pnum = pnum;
671 aeb->vol_id = vol_id;
672 aeb->lnum = lnum;
673 aeb->scrub = ((cmp_res & 2) || bitflips);
674 aeb->copy_flag = vid_hdr->copy_flag;
675 aeb->sqnum = sqnum;
676
677 if (av->highest_lnum == lnum)
678 av->last_data_size =
679 be32_to_cpu(vid_hdr->data_size);
680
681 return 0;
682 } else {
683 /*
684 * This logical eraseblock is older than the one found
685 * previously.
686 */
687 return add_to_list(ai, pnum, vol_id, lnum, ec,
688 cmp_res & 4, &ai->erase);
689 }
690 }
691
692 /*
693 * We've met this logical eraseblock for the first time, add it to the
694 * attaching information.
695 */
696
697 err = validate_vid_hdr(ubi, vid_hdr, av, pnum);
698 if (err)
699 return err;
700
701 aeb = ubi_alloc_aeb(ai, pnum, ec);
702 if (!aeb)
703 return -ENOMEM;
704
705 aeb->vol_id = vol_id;
706 aeb->lnum = lnum;
707 aeb->scrub = bitflips;
708 aeb->copy_flag = vid_hdr->copy_flag;
709 aeb->sqnum = sqnum;
710
711 if (av->highest_lnum <= lnum) {
712 av->highest_lnum = lnum;
713 av->last_data_size = be32_to_cpu(vid_hdr->data_size);
714 }
715
716 av->leb_count += 1;
717 rb_link_node(&aeb->u.rb, parent, p);
718 rb_insert_color(&aeb->u.rb, &av->root);
719 return 0;
720}
721
722/**
723 * ubi_add_av - add volume to the attaching information.
724 * @ai: attaching information
725 * @vol_id: the requested volume ID
726 *
727 * This function returns a pointer to the new volume description or an
728 * ERR_PTR if the operation failed.
729 */
730struct ubi_ainf_volume *ubi_add_av(struct ubi_attach_info *ai, int vol_id)
731{
732 bool created;
733
734 return find_or_add_av(ai, vol_id, AV_ADD, &created);
735}
736
737/**
738 * ubi_find_av - find volume in the attaching information.
739 * @ai: attaching information
740 * @vol_id: the requested volume ID
741 *
742 * This function returns a pointer to the volume description or %NULL if there
743 * are no data about this volume in the attaching information.
744 */
745struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai,
746 int vol_id)
747{
748 bool created;
749
750 return find_or_add_av((struct ubi_attach_info *)ai, vol_id, AV_FIND,
751 &created);
752}
753
754static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av,
755 struct list_head *list);
756
757/**
758 * ubi_remove_av - delete attaching information about a volume.
759 * @ai: attaching information
760 * @av: the volume attaching information to delete
761 */
762void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
763{
764 dbg_bld("remove attaching information about volume %d", av->vol_id);
765
766 rb_erase(&av->rb, &ai->volumes);
767 destroy_av(ai, av, &ai->erase);
768 ai->vols_found -= 1;
769}
770
771/**
772 * early_erase_peb - erase a physical eraseblock.
773 * @ubi: UBI device description object
774 * @ai: attaching information
775 * @pnum: physical eraseblock number to erase;
776 * @ec: erase counter value to write (%UBI_UNKNOWN if it is unknown)
777 *
778 * This function erases physical eraseblock 'pnum', and writes the erase
779 * counter header to it. This function should only be used on UBI device
780 * initialization stages, when the EBA sub-system had not been yet initialized.
781 * This function returns zero in case of success and a negative error code in
782 * case of failure.
783 */
784static int early_erase_peb(struct ubi_device *ubi,
785 const struct ubi_attach_info *ai, int pnum, int ec)
786{
787 int err;
788 struct ubi_ec_hdr *ec_hdr;
789
790 if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
791 /*
792 * Erase counter overflow. Upgrade UBI and use 64-bit
793 * erase counters internally.
794 */
795 ubi_err(ubi, "erase counter overflow at PEB %d, EC %d",
796 pnum, ec);
797 return -EINVAL;
798 }
799
800 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
801 if (!ec_hdr)
802 return -ENOMEM;
803
804 ec_hdr->ec = cpu_to_be64(ec);
805
806 err = ubi_io_sync_erase(ubi, pnum, 0);
807 if (err < 0)
808 goto out_free;
809
810 err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
811
812out_free:
813 kfree(ec_hdr);
814 return err;
815}
816
817/**
818 * ubi_early_get_peb - get a free physical eraseblock.
819 * @ubi: UBI device description object
820 * @ai: attaching information
821 *
822 * This function returns a free physical eraseblock. It is supposed to be
823 * called on the UBI initialization stages when the wear-leveling sub-system is
824 * not initialized yet. This function picks a physical eraseblocks from one of
825 * the lists, writes the EC header if it is needed, and removes it from the
826 * list.
827 *
828 * This function returns a pointer to the "aeb" of the found free PEB in case
829 * of success and an error code in case of failure.
830 */
831struct ubi_ainf_peb *ubi_early_get_peb(struct ubi_device *ubi,
832 struct ubi_attach_info *ai)
833{
834 int err = 0;
835 struct ubi_ainf_peb *aeb, *tmp_aeb;
836
837 if (!list_empty(&ai->free)) {
838 aeb = list_entry(ai->free.next, struct ubi_ainf_peb, u.list);
839 list_del(&aeb->u.list);
840 dbg_bld("return free PEB %d, EC %d", aeb->pnum, aeb->ec);
841 return aeb;
842 }
843
844 /*
845 * We try to erase the first physical eraseblock from the erase list
846 * and pick it if we succeed, or try to erase the next one if not. And
847 * so forth. We don't want to take care about bad eraseblocks here -
848 * they'll be handled later.
849 */
850 list_for_each_entry_safe(aeb, tmp_aeb, &ai->erase, u.list) {
851 if (aeb->ec == UBI_UNKNOWN)
852 aeb->ec = ai->mean_ec;
853
854 err = early_erase_peb(ubi, ai, aeb->pnum, aeb->ec+1);
855 if (err)
856 continue;
857
858 aeb->ec += 1;
859 list_del(&aeb->u.list);
860 dbg_bld("return PEB %d, EC %d", aeb->pnum, aeb->ec);
861 return aeb;
862 }
863
864 ubi_err(ubi, "no free eraseblocks");
865 return ERR_PTR(-ENOSPC);
866}
867
868/**
869 * check_corruption - check the data area of PEB.
870 * @ubi: UBI device description object
871 * @vid_hdr: the (corrupted) VID header of this PEB
872 * @pnum: the physical eraseblock number to check
873 *
874 * This is a helper function which is used to distinguish between VID header
875 * corruptions caused by power cuts and other reasons. If the PEB contains only
876 * 0xFF bytes in the data area, the VID header is most probably corrupted
877 * because of a power cut (%0 is returned in this case). Otherwise, it was
878 * probably corrupted for some other reasons (%1 is returned in this case). A
879 * negative error code is returned if a read error occurred.
880 *
881 * If the corruption reason was a power cut, UBI can safely erase this PEB.
882 * Otherwise, it should preserve it to avoid possibly destroying important
883 * information.
884 */
885static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr,
886 int pnum)
887{
888 int err;
889
890 mutex_lock(&ubi->buf_mutex);
891 memset(ubi->peb_buf, 0x00, ubi->leb_size);
892
893 err = ubi_io_read(ubi, ubi->peb_buf, pnum, ubi->leb_start,
894 ubi->leb_size);
895 if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
896 /*
897 * Bit-flips or integrity errors while reading the data area.
898 * It is difficult to say for sure what type of corruption is
899 * this, but presumably a power cut happened while this PEB was
900 * erased, so it became unstable and corrupted, and should be
901 * erased.
902 */
903 err = 0;
904 goto out_unlock;
905 }
906
907 if (err)
908 goto out_unlock;
909
910 if (ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->leb_size))
911 goto out_unlock;
912
913 ubi_err(ubi, "PEB %d contains corrupted VID header, and the data does not contain all 0xFF",
914 pnum);
915 ubi_err(ubi, "this may be a non-UBI PEB or a severe VID header corruption which requires manual inspection");
916 ubi_dump_vid_hdr(vid_hdr);
917 pr_err("hexdump of PEB %d offset %d, length %d",
918 pnum, ubi->leb_start, ubi->leb_size);
919 ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
920 ubi->peb_buf, ubi->leb_size, 1);
921 err = 1;
922
923out_unlock:
924 mutex_unlock(&ubi->buf_mutex);
925 return err;
926}
927
928static bool vol_ignored(int vol_id)
929{
930 switch (vol_id) {
931 case UBI_LAYOUT_VOLUME_ID:
932 return true;
933 }
934
935#ifdef CONFIG_MTD_UBI_FASTMAP
936 return ubi_is_fm_vol(vol_id);
937#else
938 return false;
939#endif
940}
941
942/**
943 * scan_peb - scan and process UBI headers of a PEB.
944 * @ubi: UBI device description object
945 * @ai: attaching information
946 * @pnum: the physical eraseblock number
947 * @fast: true if we're scanning for a Fastmap
948 *
949 * This function reads UBI headers of PEB @pnum, checks them, and adds
950 * information about this PEB to the corresponding list or RB-tree in the
951 * "attaching info" structure. Returns zero if the physical eraseblock was
952 * successfully handled and a negative error code in case of failure.
953 */
954static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
955 int pnum, bool fast)
956{
957 struct ubi_ec_hdr *ech = ai->ech;
958 struct ubi_vid_io_buf *vidb = ai->vidb;
959 struct ubi_vid_hdr *vidh = ubi_get_vid_hdr(vidb);
960 long long ec;
961 int err, bitflips = 0, vol_id = -1, ec_err = 0;
962
963 dbg_bld("scan PEB %d", pnum);
964
965 /* Skip bad physical eraseblocks */
966 err = ubi_io_is_bad(ubi, pnum);
967 if (err < 0)
968 return err;
969 else if (err) {
970 ai->bad_peb_count += 1;
971 return 0;
972 }
973
974 err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
975 if (err < 0)
976 return err;
977 switch (err) {
978 case 0:
979 break;
980 case UBI_IO_BITFLIPS:
981 bitflips = 1;
982 break;
983 case UBI_IO_FF:
984 ai->empty_peb_count += 1;
985 return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
986 UBI_UNKNOWN, 0, &ai->erase);
987 case UBI_IO_FF_BITFLIPS:
988 ai->empty_peb_count += 1;
989 return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
990 UBI_UNKNOWN, 1, &ai->erase);
991 case UBI_IO_BAD_HDR_EBADMSG:
992 case UBI_IO_BAD_HDR:
993 /*
994 * We have to also look at the VID header, possibly it is not
995 * corrupted. Set %bitflips flag in order to make this PEB be
996 * moved and EC be re-created.
997 */
998 ec_err = err;
999 ec = UBI_UNKNOWN;
1000 bitflips = 1;
1001 break;
1002 default:
1003 ubi_err(ubi, "'ubi_io_read_ec_hdr()' returned unknown code %d",
1004 err);
1005 return -EINVAL;
1006 }
1007
1008 if (!ec_err) {
1009 int image_seq;
1010
1011 /* Make sure UBI version is OK */
1012 if (ech->version != UBI_VERSION) {
1013 ubi_err(ubi, "this UBI version is %d, image version is %d",
1014 UBI_VERSION, (int)ech->version);
1015 return -EINVAL;
1016 }
1017
1018 ec = be64_to_cpu(ech->ec);
1019 if (ec > UBI_MAX_ERASECOUNTER) {
1020 /*
1021 * Erase counter overflow. The EC headers have 64 bits
1022 * reserved, but we anyway make use of only 31 bit
1023 * values, as this seems to be enough for any existing
1024 * flash. Upgrade UBI and use 64-bit erase counters
1025 * internally.
1026 */
1027 ubi_err(ubi, "erase counter overflow, max is %d",
1028 UBI_MAX_ERASECOUNTER);
1029 ubi_dump_ec_hdr(ech);
1030 return -EINVAL;
1031 }
1032
1033 /*
1034 * Make sure that all PEBs have the same image sequence number.
1035 * This allows us to detect situations when users flash UBI
1036 * images incorrectly, so that the flash has the new UBI image
1037 * and leftovers from the old one. This feature was added
1038 * relatively recently, and the sequence number was always
1039 * zero, because old UBI implementations always set it to zero.
1040 * For this reasons, we do not panic if some PEBs have zero
1041 * sequence number, while other PEBs have non-zero sequence
1042 * number.
1043 */
1044 image_seq = be32_to_cpu(ech->image_seq);
1045 if (!ubi->image_seq)
1046 ubi->image_seq = image_seq;
1047 if (image_seq && ubi->image_seq != image_seq) {
1048 ubi_err(ubi, "bad image sequence number %d in PEB %d, expected %d",
1049 image_seq, pnum, ubi->image_seq);
1050 ubi_dump_ec_hdr(ech);
1051 return -EINVAL;
1052 }
1053 }
1054
1055 /* OK, we've done with the EC header, let's look at the VID header */
1056
1057 err = ubi_io_read_vid_hdr(ubi, pnum, vidb, 0);
1058 if (err < 0)
1059 return err;
1060 switch (err) {
1061 case 0:
1062 break;
1063 case UBI_IO_BITFLIPS:
1064 bitflips = 1;
1065 break;
1066 case UBI_IO_BAD_HDR_EBADMSG:
1067 if (ec_err == UBI_IO_BAD_HDR_EBADMSG)
1068 /*
1069 * Both EC and VID headers are corrupted and were read
1070 * with data integrity error, probably this is a bad
1071 * PEB, bit it is not marked as bad yet. This may also
1072 * be a result of power cut during erasure.
1073 */
1074 ai->maybe_bad_peb_count += 1;
1075 case UBI_IO_BAD_HDR:
1076 /*
1077 * If we're facing a bad VID header we have to drop *all*
1078 * Fastmap data structures we find. The most recent Fastmap
1079 * could be bad and therefore there is a chance that we attach
1080 * from an old one. On a fine MTD stack a PEB must not render
1081 * bad all of a sudden, but the reality is different.
1082 * So, let's be paranoid and help finding the root cause by
1083 * falling back to scanning mode instead of attaching with a
1084 * bad EBA table and cause data corruption which is hard to
1085 * analyze.
1086 */
1087 if (fast)
1088 ai->force_full_scan = 1;
1089
1090 if (ec_err)
1091 /*
1092 * Both headers are corrupted. There is a possibility
1093 * that this a valid UBI PEB which has corresponding
1094 * LEB, but the headers are corrupted. However, it is
1095 * impossible to distinguish it from a PEB which just
1096 * contains garbage because of a power cut during erase
1097 * operation. So we just schedule this PEB for erasure.
1098 *
1099 * Besides, in case of NOR flash, we deliberately
1100 * corrupt both headers because NOR flash erasure is
1101 * slow and can start from the end.
1102 */
1103 err = 0;
1104 else
1105 /*
1106 * The EC was OK, but the VID header is corrupted. We
1107 * have to check what is in the data area.
1108 */
1109 err = check_corruption(ubi, vidh, pnum);
1110
1111 if (err < 0)
1112 return err;
1113 else if (!err)
1114 /* This corruption is caused by a power cut */
1115 err = add_to_list(ai, pnum, UBI_UNKNOWN,
1116 UBI_UNKNOWN, ec, 1, &ai->erase);
1117 else
1118 /* This is an unexpected corruption */
1119 err = add_corrupted(ai, pnum, ec);
1120 if (err)
1121 return err;
1122 goto adjust_mean_ec;
1123 case UBI_IO_FF_BITFLIPS:
1124 err = add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
1125 ec, 1, &ai->erase);
1126 if (err)
1127 return err;
1128 goto adjust_mean_ec;
1129 case UBI_IO_FF:
1130 if (ec_err || bitflips)
1131 err = add_to_list(ai, pnum, UBI_UNKNOWN,
1132 UBI_UNKNOWN, ec, 1, &ai->erase);
1133 else
1134 err = add_to_list(ai, pnum, UBI_UNKNOWN,
1135 UBI_UNKNOWN, ec, 0, &ai->free);
1136 if (err)
1137 return err;
1138 goto adjust_mean_ec;
1139 default:
1140 ubi_err(ubi, "'ubi_io_read_vid_hdr()' returned unknown code %d",
1141 err);
1142 return -EINVAL;
1143 }
1144
1145 vol_id = be32_to_cpu(vidh->vol_id);
1146 if (vol_id > UBI_MAX_VOLUMES && !vol_ignored(vol_id)) {
1147 int lnum = be32_to_cpu(vidh->lnum);
1148
1149 /* Unsupported internal volume */
1150 switch (vidh->compat) {
1151 case UBI_COMPAT_DELETE:
1152 ubi_msg(ubi, "\"delete\" compatible internal volume %d:%d found, will remove it",
1153 vol_id, lnum);
1154
1155 err = add_to_list(ai, pnum, vol_id, lnum,
1156 ec, 1, &ai->erase);
1157 if (err)
1158 return err;
1159 return 0;
1160
1161 case UBI_COMPAT_RO:
1162 ubi_msg(ubi, "read-only compatible internal volume %d:%d found, switch to read-only mode",
1163 vol_id, lnum);
1164 ubi->ro_mode = 1;
1165 break;
1166
1167 case UBI_COMPAT_PRESERVE:
1168 ubi_msg(ubi, "\"preserve\" compatible internal volume %d:%d found",
1169 vol_id, lnum);
1170 err = add_to_list(ai, pnum, vol_id, lnum,
1171 ec, 0, &ai->alien);
1172 if (err)
1173 return err;
1174 return 0;
1175
1176 case UBI_COMPAT_REJECT:
1177 ubi_err(ubi, "incompatible internal volume %d:%d found",
1178 vol_id, lnum);
1179 return -EINVAL;
1180 }
1181 }
1182
1183 if (ec_err)
1184 ubi_warn(ubi, "valid VID header but corrupted EC header at PEB %d",
1185 pnum);
1186
1187 if (ubi_is_fm_vol(vol_id))
1188 err = add_fastmap(ai, pnum, vidh, ec);
1189 else
1190 err = ubi_add_to_av(ubi, ai, pnum, ec, vidh, bitflips);
1191
1192 if (err)
1193 return err;
1194
1195adjust_mean_ec:
1196 if (!ec_err) {
1197 ai->ec_sum += ec;
1198 ai->ec_count += 1;
1199 if (ec > ai->max_ec)
1200 ai->max_ec = ec;
1201 if (ec < ai->min_ec)
1202 ai->min_ec = ec;
1203 }
1204
1205 return 0;
1206}
1207
1208/**
1209 * late_analysis - analyze the overall situation with PEB.
1210 * @ubi: UBI device description object
1211 * @ai: attaching information
1212 *
1213 * This is a helper function which takes a look what PEBs we have after we
1214 * gather information about all of them ("ai" is compete). It decides whether
1215 * the flash is empty and should be formatted of whether there are too many
1216 * corrupted PEBs and we should not attach this MTD device. Returns zero if we
1217 * should proceed with attaching the MTD device, and %-EINVAL if we should not.
1218 */
1219static int late_analysis(struct ubi_device *ubi, struct ubi_attach_info *ai)
1220{
1221 struct ubi_ainf_peb *aeb;
1222 int max_corr, peb_count;
1223
1224 peb_count = ubi->peb_count - ai->bad_peb_count - ai->alien_peb_count;
1225 max_corr = peb_count / 20 ?: 8;
1226
1227 /*
1228 * Few corrupted PEBs is not a problem and may be just a result of
1229 * unclean reboots. However, many of them may indicate some problems
1230 * with the flash HW or driver.
1231 */
1232 if (ai->corr_peb_count) {
1233 ubi_err(ubi, "%d PEBs are corrupted and preserved",
1234 ai->corr_peb_count);
1235 pr_err("Corrupted PEBs are:");
1236 list_for_each_entry(aeb, &ai->corr, u.list)
1237 pr_cont(" %d", aeb->pnum);
1238 pr_cont("\n");
1239
1240 /*
1241 * If too many PEBs are corrupted, we refuse attaching,
1242 * otherwise, only print a warning.
1243 */
1244 if (ai->corr_peb_count >= max_corr) {
1245 ubi_err(ubi, "too many corrupted PEBs, refusing");
1246 return -EINVAL;
1247 }
1248 }
1249
1250 if (ai->empty_peb_count + ai->maybe_bad_peb_count == peb_count) {
1251 /*
1252 * All PEBs are empty, or almost all - a couple PEBs look like
1253 * they may be bad PEBs which were not marked as bad yet.
1254 *
1255 * This piece of code basically tries to distinguish between
1256 * the following situations:
1257 *
1258 * 1. Flash is empty, but there are few bad PEBs, which are not
1259 * marked as bad so far, and which were read with error. We
1260 * want to go ahead and format this flash. While formatting,
1261 * the faulty PEBs will probably be marked as bad.
1262 *
1263 * 2. Flash contains non-UBI data and we do not want to format
1264 * it and destroy possibly important information.
1265 */
1266 if (ai->maybe_bad_peb_count <= 2) {
1267 ai->is_empty = 1;
1268 ubi_msg(ubi, "empty MTD device detected");
1269 get_random_bytes(&ubi->image_seq,
1270 sizeof(ubi->image_seq));
1271 } else {
1272 ubi_err(ubi, "MTD device is not UBI-formatted and possibly contains non-UBI data - refusing it");
1273 return -EINVAL;
1274 }
1275
1276 }
1277
1278 return 0;
1279}
1280
1281/**
1282 * destroy_av - free volume attaching information.
1283 * @av: volume attaching information
1284 * @ai: attaching information
1285 * @list: put the aeb elements in there if !NULL, otherwise free them
1286 *
1287 * This function destroys the volume attaching information.
1288 */
1289static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av,
1290 struct list_head *list)
1291{
1292 struct ubi_ainf_peb *aeb;
1293 struct rb_node *this = av->root.rb_node;
1294
1295 while (this) {
1296 if (this->rb_left)
1297 this = this->rb_left;
1298 else if (this->rb_right)
1299 this = this->rb_right;
1300 else {
1301 aeb = rb_entry(this, struct ubi_ainf_peb, u.rb);
1302 this = rb_parent(this);
1303 if (this) {
1304 if (this->rb_left == &aeb->u.rb)
1305 this->rb_left = NULL;
1306 else
1307 this->rb_right = NULL;
1308 }
1309
1310 if (list)
1311 list_add_tail(&aeb->u.list, list);
1312 else
1313 ubi_free_aeb(ai, aeb);
1314 }
1315 }
1316 kfree(av);
1317}
1318
1319/**
1320 * destroy_ai - destroy attaching information.
1321 * @ai: attaching information
1322 */
1323static void destroy_ai(struct ubi_attach_info *ai)
1324{
1325 struct ubi_ainf_peb *aeb, *aeb_tmp;
1326 struct ubi_ainf_volume *av;
1327 struct rb_node *rb;
1328
1329 list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, 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->erase, u.list) {
1334 list_del(&aeb->u.list);
1335 ubi_free_aeb(ai, aeb);
1336 }
1337 list_for_each_entry_safe(aeb, aeb_tmp, &ai->corr, u.list) {
1338 list_del(&aeb->u.list);
1339 ubi_free_aeb(ai, aeb);
1340 }
1341 list_for_each_entry_safe(aeb, aeb_tmp, &ai->free, u.list) {
1342 list_del(&aeb->u.list);
1343 ubi_free_aeb(ai, aeb);
1344 }
1345 list_for_each_entry_safe(aeb, aeb_tmp, &ai->fastmap, u.list) {
1346 list_del(&aeb->u.list);
1347 ubi_free_aeb(ai, aeb);
1348 }
1349
1350 /* Destroy the volume RB-tree */
1351 rb = ai->volumes.rb_node;
1352 while (rb) {
1353 if (rb->rb_left)
1354 rb = rb->rb_left;
1355 else if (rb->rb_right)
1356 rb = rb->rb_right;
1357 else {
1358 av = rb_entry(rb, struct ubi_ainf_volume, rb);
1359
1360 rb = rb_parent(rb);
1361 if (rb) {
1362 if (rb->rb_left == &av->rb)
1363 rb->rb_left = NULL;
1364 else
1365 rb->rb_right = NULL;
1366 }
1367
1368 destroy_av(ai, av, NULL);
1369 }
1370 }
1371
1372 kmem_cache_destroy(ai->aeb_slab_cache);
1373 kfree(ai);
1374}
1375
1376/**
1377 * scan_all - scan entire MTD device.
1378 * @ubi: UBI device description object
1379 * @ai: attach info object
1380 * @start: start scanning at this PEB
1381 *
1382 * This function does full scanning of an MTD device and returns complete
1383 * information about it in form of a "struct ubi_attach_info" object. In case
1384 * of failure, an error code is returned.
1385 */
1386static int scan_all(struct ubi_device *ubi, struct ubi_attach_info *ai,
1387 int start)
1388{
1389 int err, pnum;
1390 struct rb_node *rb1, *rb2;
1391 struct ubi_ainf_volume *av;
1392 struct ubi_ainf_peb *aeb;
1393
1394 err = -ENOMEM;
1395
1396 ai->ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1397 if (!ai->ech)
1398 return err;
1399
1400 ai->vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
1401 if (!ai->vidb)
1402 goto out_ech;
1403
1404 for (pnum = start; pnum < ubi->peb_count; pnum++) {
1405 cond_resched();
1406
1407 dbg_gen("process PEB %d", pnum);
1408 err = scan_peb(ubi, ai, pnum, false);
1409 if (err < 0)
1410 goto out_vidh;
1411 }
1412
1413 ubi_msg(ubi, "scanning is finished");
1414
1415 /* Calculate mean erase counter */
1416 if (ai->ec_count)
1417 ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count);
1418
1419 err = late_analysis(ubi, ai);
1420 if (err)
1421 goto out_vidh;
1422
1423 /*
1424 * In case of unknown erase counter we use the mean erase counter
1425 * value.
1426 */
1427 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1428 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
1429 if (aeb->ec == UBI_UNKNOWN)
1430 aeb->ec = ai->mean_ec;
1431 }
1432
1433 list_for_each_entry(aeb, &ai->free, u.list) {
1434 if (aeb->ec == UBI_UNKNOWN)
1435 aeb->ec = ai->mean_ec;
1436 }
1437
1438 list_for_each_entry(aeb, &ai->corr, u.list)
1439 if (aeb->ec == UBI_UNKNOWN)
1440 aeb->ec = ai->mean_ec;
1441
1442 list_for_each_entry(aeb, &ai->erase, u.list)
1443 if (aeb->ec == UBI_UNKNOWN)
1444 aeb->ec = ai->mean_ec;
1445
1446 err = self_check_ai(ubi, ai);
1447 if (err)
1448 goto out_vidh;
1449
1450 ubi_free_vid_buf(ai->vidb);
1451 kfree(ai->ech);
1452
1453 return 0;
1454
1455out_vidh:
1456 ubi_free_vid_buf(ai->vidb);
1457out_ech:
1458 kfree(ai->ech);
1459 return err;
1460}
1461
1462static struct ubi_attach_info *alloc_ai(void)
1463{
1464 struct ubi_attach_info *ai;
1465
1466 ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL);
1467 if (!ai)
1468 return ai;
1469
1470 INIT_LIST_HEAD(&ai->corr);
1471 INIT_LIST_HEAD(&ai->free);
1472 INIT_LIST_HEAD(&ai->erase);
1473 INIT_LIST_HEAD(&ai->alien);
1474 INIT_LIST_HEAD(&ai->fastmap);
1475 ai->volumes = RB_ROOT;
1476 ai->aeb_slab_cache = kmem_cache_create("ubi_aeb_slab_cache",
1477 sizeof(struct ubi_ainf_peb),
1478 0, 0, NULL);
1479 if (!ai->aeb_slab_cache) {
1480 kfree(ai);
1481 ai = NULL;
1482 }
1483
1484 return ai;
1485}
1486
1487#ifdef CONFIG_MTD_UBI_FASTMAP
1488
1489/**
1490 * scan_fast - try to find a fastmap and attach from it.
1491 * @ubi: UBI device description object
1492 * @ai: attach info object
1493 *
1494 * Returns 0 on success, negative return values indicate an internal
1495 * error.
1496 * UBI_NO_FASTMAP denotes that no fastmap was found.
1497 * UBI_BAD_FASTMAP denotes that the found fastmap was invalid.
1498 */
1499static int scan_fast(struct ubi_device *ubi, struct ubi_attach_info **ai)
1500{
1501 int err, pnum;
1502 struct ubi_attach_info *scan_ai;
1503
1504 err = -ENOMEM;
1505
1506 scan_ai = alloc_ai();
1507 if (!scan_ai)
1508 goto out;
1509
1510 scan_ai->ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1511 if (!scan_ai->ech)
1512 goto out_ai;
1513
1514 scan_ai->vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
1515 if (!scan_ai->vidb)
1516 goto out_ech;
1517
1518 for (pnum = 0; pnum < UBI_FM_MAX_START; pnum++) {
1519 cond_resched();
1520
1521 dbg_gen("process PEB %d", pnum);
1522 err = scan_peb(ubi, scan_ai, pnum, true);
1523 if (err < 0)
1524 goto out_vidh;
1525 }
1526
1527 ubi_free_vid_buf(scan_ai->vidb);
1528 kfree(scan_ai->ech);
1529
1530 if (scan_ai->force_full_scan)
1531 err = UBI_NO_FASTMAP;
1532 else
1533 err = ubi_scan_fastmap(ubi, *ai, scan_ai);
1534
1535 if (err) {
1536 /*
1537 * Didn't attach via fastmap, do a full scan but reuse what
1538 * we've aready scanned.
1539 */
1540 destroy_ai(*ai);
1541 *ai = scan_ai;
1542 } else
1543 destroy_ai(scan_ai);
1544
1545 return err;
1546
1547out_vidh:
1548 ubi_free_vid_buf(scan_ai->vidb);
1549out_ech:
1550 kfree(scan_ai->ech);
1551out_ai:
1552 destroy_ai(scan_ai);
1553out:
1554 return err;
1555}
1556
1557#endif
1558
1559/**
1560 * ubi_attach - attach an MTD device.
1561 * @ubi: UBI device descriptor
1562 * @force_scan: if set to non-zero attach by scanning
1563 *
1564 * This function returns zero in case of success and a negative error code in
1565 * case of failure.
1566 */
1567int ubi_attach(struct ubi_device *ubi, int force_scan)
1568{
1569 int err;
1570 struct ubi_attach_info *ai;
1571
1572 ai = alloc_ai();
1573 if (!ai)
1574 return -ENOMEM;
1575
1576#ifdef CONFIG_MTD_UBI_FASTMAP
1577 /* On small flash devices we disable fastmap in any case. */
1578 if ((int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd) <= UBI_FM_MAX_START) {
1579 ubi->fm_disabled = 1;
1580 force_scan = 1;
1581 }
1582
1583 if (force_scan)
1584 err = scan_all(ubi, ai, 0);
1585 else {
1586 err = scan_fast(ubi, &ai);
1587 if (err > 0 || mtd_is_eccerr(err)) {
1588 if (err != UBI_NO_FASTMAP) {
1589 destroy_ai(ai);
1590 ai = alloc_ai();
1591 if (!ai)
1592 return -ENOMEM;
1593
1594 err = scan_all(ubi, ai, 0);
1595 } else {
1596 err = scan_all(ubi, ai, UBI_FM_MAX_START);
1597 }
1598 }
1599 }
1600#else
1601 err = scan_all(ubi, ai, 0);
1602#endif
1603 if (err)
1604 goto out_ai;
1605
1606 ubi->bad_peb_count = ai->bad_peb_count;
1607 ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count;
1608 ubi->corr_peb_count = ai->corr_peb_count;
1609 ubi->max_ec = ai->max_ec;
1610 ubi->mean_ec = ai->mean_ec;
1611 dbg_gen("max. sequence number: %llu", ai->max_sqnum);
1612
1613 err = ubi_read_volume_table(ubi, ai);
1614 if (err)
1615 goto out_ai;
1616
1617 err = ubi_wl_init(ubi, ai);
1618 if (err)
1619 goto out_vtbl;
1620
1621 err = ubi_eba_init(ubi, ai);
1622 if (err)
1623 goto out_wl;
1624
1625#ifdef CONFIG_MTD_UBI_FASTMAP
1626 if (ubi->fm && ubi_dbg_chk_fastmap(ubi)) {
1627 struct ubi_attach_info *scan_ai;
1628
1629 scan_ai = alloc_ai();
1630 if (!scan_ai) {
1631 err = -ENOMEM;
1632 goto out_wl;
1633 }
1634
1635 err = scan_all(ubi, scan_ai, 0);
1636 if (err) {
1637 destroy_ai(scan_ai);
1638 goto out_wl;
1639 }
1640
1641 err = self_check_eba(ubi, ai, scan_ai);
1642 destroy_ai(scan_ai);
1643
1644 if (err)
1645 goto out_wl;
1646 }
1647#endif
1648
1649 destroy_ai(ai);
1650 return 0;
1651
1652out_wl:
1653 ubi_wl_close(ubi);
1654out_vtbl:
1655 ubi_free_internal_volumes(ubi);
1656 vfree(ubi->vtbl);
1657out_ai:
1658 destroy_ai(ai);
1659 return err;
1660}
1661
1662/**
1663 * self_check_ai - check the attaching information.
1664 * @ubi: UBI device description object
1665 * @ai: attaching information
1666 *
1667 * This function returns zero if the attaching information is all right, and a
1668 * negative error code if not or if an error occurred.
1669 */
1670static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai)
1671{
1672 struct ubi_vid_io_buf *vidb = ai->vidb;
1673 struct ubi_vid_hdr *vidh = ubi_get_vid_hdr(vidb);
1674 int pnum, err, vols_found = 0;
1675 struct rb_node *rb1, *rb2;
1676 struct ubi_ainf_volume *av;
1677 struct ubi_ainf_peb *aeb, *last_aeb;
1678 uint8_t *buf;
1679
1680 if (!ubi_dbg_chk_gen(ubi))
1681 return 0;
1682
1683 /*
1684 * At first, check that attaching information is OK.
1685 */
1686 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1687 int leb_count = 0;
1688
1689 cond_resched();
1690
1691 vols_found += 1;
1692
1693 if (ai->is_empty) {
1694 ubi_err(ubi, "bad is_empty flag");
1695 goto bad_av;
1696 }
1697
1698 if (av->vol_id < 0 || av->highest_lnum < 0 ||
1699 av->leb_count < 0 || av->vol_type < 0 || av->used_ebs < 0 ||
1700 av->data_pad < 0 || av->last_data_size < 0) {
1701 ubi_err(ubi, "negative values");
1702 goto bad_av;
1703 }
1704
1705 if (av->vol_id >= UBI_MAX_VOLUMES &&
1706 av->vol_id < UBI_INTERNAL_VOL_START) {
1707 ubi_err(ubi, "bad vol_id");
1708 goto bad_av;
1709 }
1710
1711 if (av->vol_id > ai->highest_vol_id) {
1712 ubi_err(ubi, "highest_vol_id is %d, but vol_id %d is there",
1713 ai->highest_vol_id, av->vol_id);
1714 goto out;
1715 }
1716
1717 if (av->vol_type != UBI_DYNAMIC_VOLUME &&
1718 av->vol_type != UBI_STATIC_VOLUME) {
1719 ubi_err(ubi, "bad vol_type");
1720 goto bad_av;
1721 }
1722
1723 if (av->data_pad > ubi->leb_size / 2) {
1724 ubi_err(ubi, "bad data_pad");
1725 goto bad_av;
1726 }
1727
1728 last_aeb = NULL;
1729 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1730 cond_resched();
1731
1732 last_aeb = aeb;
1733 leb_count += 1;
1734
1735 if (aeb->pnum < 0 || aeb->ec < 0) {
1736 ubi_err(ubi, "negative values");
1737 goto bad_aeb;
1738 }
1739
1740 if (aeb->ec < ai->min_ec) {
1741 ubi_err(ubi, "bad ai->min_ec (%d), %d found",
1742 ai->min_ec, aeb->ec);
1743 goto bad_aeb;
1744 }
1745
1746 if (aeb->ec > ai->max_ec) {
1747 ubi_err(ubi, "bad ai->max_ec (%d), %d found",
1748 ai->max_ec, aeb->ec);
1749 goto bad_aeb;
1750 }
1751
1752 if (aeb->pnum >= ubi->peb_count) {
1753 ubi_err(ubi, "too high PEB number %d, total PEBs %d",
1754 aeb->pnum, ubi->peb_count);
1755 goto bad_aeb;
1756 }
1757
1758 if (av->vol_type == UBI_STATIC_VOLUME) {
1759 if (aeb->lnum >= av->used_ebs) {
1760 ubi_err(ubi, "bad lnum or used_ebs");
1761 goto bad_aeb;
1762 }
1763 } else {
1764 if (av->used_ebs != 0) {
1765 ubi_err(ubi, "non-zero used_ebs");
1766 goto bad_aeb;
1767 }
1768 }
1769
1770 if (aeb->lnum > av->highest_lnum) {
1771 ubi_err(ubi, "incorrect highest_lnum or lnum");
1772 goto bad_aeb;
1773 }
1774 }
1775
1776 if (av->leb_count != leb_count) {
1777 ubi_err(ubi, "bad leb_count, %d objects in the tree",
1778 leb_count);
1779 goto bad_av;
1780 }
1781
1782 if (!last_aeb)
1783 continue;
1784
1785 aeb = last_aeb;
1786
1787 if (aeb->lnum != av->highest_lnum) {
1788 ubi_err(ubi, "bad highest_lnum");
1789 goto bad_aeb;
1790 }
1791 }
1792
1793 if (vols_found != ai->vols_found) {
1794 ubi_err(ubi, "bad ai->vols_found %d, should be %d",
1795 ai->vols_found, vols_found);
1796 goto out;
1797 }
1798
1799 /* Check that attaching information is correct */
1800 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1801 last_aeb = NULL;
1802 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1803 int vol_type;
1804
1805 cond_resched();
1806
1807 last_aeb = aeb;
1808
1809 err = ubi_io_read_vid_hdr(ubi, aeb->pnum, vidb, 1);
1810 if (err && err != UBI_IO_BITFLIPS) {
1811 ubi_err(ubi, "VID header is not OK (%d)",
1812 err);
1813 if (err > 0)
1814 err = -EIO;
1815 return err;
1816 }
1817
1818 vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1819 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1820 if (av->vol_type != vol_type) {
1821 ubi_err(ubi, "bad vol_type");
1822 goto bad_vid_hdr;
1823 }
1824
1825 if (aeb->sqnum != be64_to_cpu(vidh->sqnum)) {
1826 ubi_err(ubi, "bad sqnum %llu", aeb->sqnum);
1827 goto bad_vid_hdr;
1828 }
1829
1830 if (av->vol_id != be32_to_cpu(vidh->vol_id)) {
1831 ubi_err(ubi, "bad vol_id %d", av->vol_id);
1832 goto bad_vid_hdr;
1833 }
1834
1835 if (av->compat != vidh->compat) {
1836 ubi_err(ubi, "bad compat %d", vidh->compat);
1837 goto bad_vid_hdr;
1838 }
1839
1840 if (aeb->lnum != be32_to_cpu(vidh->lnum)) {
1841 ubi_err(ubi, "bad lnum %d", aeb->lnum);
1842 goto bad_vid_hdr;
1843 }
1844
1845 if (av->used_ebs != be32_to_cpu(vidh->used_ebs)) {
1846 ubi_err(ubi, "bad used_ebs %d", av->used_ebs);
1847 goto bad_vid_hdr;
1848 }
1849
1850 if (av->data_pad != be32_to_cpu(vidh->data_pad)) {
1851 ubi_err(ubi, "bad data_pad %d", av->data_pad);
1852 goto bad_vid_hdr;
1853 }
1854 }
1855
1856 if (!last_aeb)
1857 continue;
1858
1859 if (av->highest_lnum != be32_to_cpu(vidh->lnum)) {
1860 ubi_err(ubi, "bad highest_lnum %d", av->highest_lnum);
1861 goto bad_vid_hdr;
1862 }
1863
1864 if (av->last_data_size != be32_to_cpu(vidh->data_size)) {
1865 ubi_err(ubi, "bad last_data_size %d",
1866 av->last_data_size);
1867 goto bad_vid_hdr;
1868 }
1869 }
1870
1871 /*
1872 * Make sure that all the physical eraseblocks are in one of the lists
1873 * or trees.
1874 */
1875 buf = kzalloc(ubi->peb_count, GFP_KERNEL);
1876 if (!buf)
1877 return -ENOMEM;
1878
1879 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1880 err = ubi_io_is_bad(ubi, pnum);
1881 if (err < 0) {
1882 kfree(buf);
1883 return err;
1884 } else if (err)
1885 buf[pnum] = 1;
1886 }
1887
1888 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb)
1889 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
1890 buf[aeb->pnum] = 1;
1891
1892 list_for_each_entry(aeb, &ai->free, u.list)
1893 buf[aeb->pnum] = 1;
1894
1895 list_for_each_entry(aeb, &ai->corr, u.list)
1896 buf[aeb->pnum] = 1;
1897
1898 list_for_each_entry(aeb, &ai->erase, u.list)
1899 buf[aeb->pnum] = 1;
1900
1901 list_for_each_entry(aeb, &ai->alien, u.list)
1902 buf[aeb->pnum] = 1;
1903
1904 err = 0;
1905 for (pnum = 0; pnum < ubi->peb_count; pnum++)
1906 if (!buf[pnum]) {
1907 ubi_err(ubi, "PEB %d is not referred", pnum);
1908 err = 1;
1909 }
1910
1911 kfree(buf);
1912 if (err)
1913 goto out;
1914 return 0;
1915
1916bad_aeb:
1917 ubi_err(ubi, "bad attaching information about LEB %d", aeb->lnum);
1918 ubi_dump_aeb(aeb, 0);
1919 ubi_dump_av(av);
1920 goto out;
1921
1922bad_av:
1923 ubi_err(ubi, "bad attaching information about volume %d", av->vol_id);
1924 ubi_dump_av(av);
1925 goto out;
1926
1927bad_vid_hdr:
1928 ubi_err(ubi, "bad attaching information about volume %d", av->vol_id);
1929 ubi_dump_av(av);
1930 ubi_dump_vid_hdr(vidh);
1931
1932out:
1933 dump_stack();
1934 return -EINVAL;
1935}