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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/* Temporary variables used during scanning */
95static struct ubi_ec_hdr *ech;
96static struct ubi_vid_hdr *vidh;
97
98/**
99 * add_to_list - add physical eraseblock to a list.
100 * @ai: attaching information
101 * @pnum: physical eraseblock number to add
102 * @vol_id: the last used volume id for the PEB
103 * @lnum: the last used LEB number for the PEB
104 * @ec: erase counter of the physical eraseblock
105 * @to_head: if not zero, add to the head of the list
106 * @list: the list to add to
107 *
108 * This function allocates a 'struct ubi_ainf_peb' object for physical
109 * eraseblock @pnum and adds it to the "free", "erase", or "alien" lists.
110 * It stores the @lnum and @vol_id alongside, which can both be
111 * %UBI_UNKNOWN if they are not available, not readable, or not assigned.
112 * If @to_head is not zero, PEB will be added to the head of the list, which
113 * basically means it will be processed first later. E.g., we add corrupted
114 * PEBs (corrupted due to power cuts) to the head of the erase list to make
115 * sure we erase them first and get rid of corruptions ASAP. This function
116 * returns zero in case of success and a negative error code in case of
117 * failure.
118 */
119static int add_to_list(struct ubi_attach_info *ai, int pnum, int vol_id,
120 int lnum, int ec, int to_head, struct list_head *list)
121{
122 struct ubi_ainf_peb *aeb;
123
124 if (list == &ai->free) {
125 dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
126 } else if (list == &ai->erase) {
127 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
128 } else if (list == &ai->alien) {
129 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
130 ai->alien_peb_count += 1;
131 } else
132 BUG();
133
134 aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL);
135 if (!aeb)
136 return -ENOMEM;
137
138 aeb->pnum = pnum;
139 aeb->vol_id = vol_id;
140 aeb->lnum = lnum;
141 aeb->ec = ec;
142 if (to_head)
143 list_add(&aeb->u.list, list);
144 else
145 list_add_tail(&aeb->u.list, list);
146 return 0;
147}
148
149/**
150 * add_corrupted - add a corrupted physical eraseblock.
151 * @ai: attaching information
152 * @pnum: physical eraseblock number to add
153 * @ec: erase counter of the physical eraseblock
154 *
155 * This function allocates a 'struct ubi_ainf_peb' object for a corrupted
156 * physical eraseblock @pnum and adds it to the 'corr' list. The corruption
157 * was presumably not caused by a power cut. Returns zero in case of success
158 * and a negative error code in case of failure.
159 */
160static int add_corrupted(struct ubi_attach_info *ai, int pnum, int ec)
161{
162 struct ubi_ainf_peb *aeb;
163
164 dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
165
166 aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL);
167 if (!aeb)
168 return -ENOMEM;
169
170 ai->corr_peb_count += 1;
171 aeb->pnum = pnum;
172 aeb->ec = ec;
173 list_add(&aeb->u.list, &ai->corr);
174 return 0;
175}
176
177/**
178 * validate_vid_hdr - check volume identifier header.
179 * @vid_hdr: the volume identifier header to check
180 * @av: information about the volume this logical eraseblock belongs to
181 * @pnum: physical eraseblock number the VID header came from
182 *
183 * This function checks that data stored in @vid_hdr is consistent. Returns
184 * non-zero if an inconsistency was found and zero if not.
185 *
186 * Note, UBI does sanity check of everything it reads from the flash media.
187 * Most of the checks are done in the I/O sub-system. Here we check that the
188 * information in the VID header is consistent to the information in other VID
189 * headers of the same volume.
190 */
191static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
192 const struct ubi_ainf_volume *av, int pnum)
193{
194 int vol_type = vid_hdr->vol_type;
195 int vol_id = be32_to_cpu(vid_hdr->vol_id);
196 int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
197 int data_pad = be32_to_cpu(vid_hdr->data_pad);
198
199 if (av->leb_count != 0) {
200 int av_vol_type;
201
202 /*
203 * This is not the first logical eraseblock belonging to this
204 * volume. Ensure that the data in its VID header is consistent
205 * to the data in previous logical eraseblock headers.
206 */
207
208 if (vol_id != av->vol_id) {
209 ubi_err("inconsistent vol_id");
210 goto bad;
211 }
212
213 if (av->vol_type == UBI_STATIC_VOLUME)
214 av_vol_type = UBI_VID_STATIC;
215 else
216 av_vol_type = UBI_VID_DYNAMIC;
217
218 if (vol_type != av_vol_type) {
219 ubi_err("inconsistent vol_type");
220 goto bad;
221 }
222
223 if (used_ebs != av->used_ebs) {
224 ubi_err("inconsistent used_ebs");
225 goto bad;
226 }
227
228 if (data_pad != av->data_pad) {
229 ubi_err("inconsistent data_pad");
230 goto bad;
231 }
232 }
233
234 return 0;
235
236bad:
237 ubi_err("inconsistent VID header at PEB %d", pnum);
238 ubi_dump_vid_hdr(vid_hdr);
239 ubi_dump_av(av);
240 return -EINVAL;
241}
242
243/**
244 * add_volume - add volume to the attaching information.
245 * @ai: attaching information
246 * @vol_id: ID of the volume to add
247 * @pnum: physical eraseblock number
248 * @vid_hdr: volume identifier header
249 *
250 * If the volume corresponding to the @vid_hdr logical eraseblock is already
251 * present in the attaching information, this function does nothing. Otherwise
252 * it adds corresponding volume to the attaching information. Returns a pointer
253 * to the allocated "av" object in case of success and a negative error code in
254 * case of failure.
255 */
256static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai,
257 int vol_id, int pnum,
258 const struct ubi_vid_hdr *vid_hdr)
259{
260 struct ubi_ainf_volume *av;
261 struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
262
263 ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
264
265 /* Walk the volume RB-tree to look if this volume is already present */
266 while (*p) {
267 parent = *p;
268 av = rb_entry(parent, struct ubi_ainf_volume, rb);
269
270 if (vol_id == av->vol_id)
271 return av;
272
273 if (vol_id > av->vol_id)
274 p = &(*p)->rb_left;
275 else
276 p = &(*p)->rb_right;
277 }
278
279 /* The volume is absent - add it */
280 av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL);
281 if (!av)
282 return ERR_PTR(-ENOMEM);
283
284 av->highest_lnum = av->leb_count = 0;
285 av->vol_id = vol_id;
286 av->root = RB_ROOT;
287 av->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
288 av->data_pad = be32_to_cpu(vid_hdr->data_pad);
289 av->compat = vid_hdr->compat;
290 av->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
291 : UBI_STATIC_VOLUME;
292 if (vol_id > ai->highest_vol_id)
293 ai->highest_vol_id = vol_id;
294
295 rb_link_node(&av->rb, parent, p);
296 rb_insert_color(&av->rb, &ai->volumes);
297 ai->vols_found += 1;
298 dbg_bld("added volume %d", vol_id);
299 return av;
300}
301
302/**
303 * ubi_compare_lebs - find out which logical eraseblock is newer.
304 * @ubi: UBI device description object
305 * @aeb: first logical eraseblock to compare
306 * @pnum: physical eraseblock number of the second logical eraseblock to
307 * compare
308 * @vid_hdr: volume identifier header of the second logical eraseblock
309 *
310 * This function compares 2 copies of a LEB and informs which one is newer. In
311 * case of success this function returns a positive value, in case of failure, a
312 * negative error code is returned. The success return codes use the following
313 * bits:
314 * o bit 0 is cleared: the first PEB (described by @aeb) is newer than the
315 * second PEB (described by @pnum and @vid_hdr);
316 * o bit 0 is set: the second PEB is newer;
317 * o bit 1 is cleared: no bit-flips were detected in the newer LEB;
318 * o bit 1 is set: bit-flips were detected in the newer LEB;
319 * o bit 2 is cleared: the older LEB is not corrupted;
320 * o bit 2 is set: the older LEB is corrupted.
321 */
322int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
323 int pnum, const struct ubi_vid_hdr *vid_hdr)
324{
325 int len, err, second_is_newer, bitflips = 0, corrupted = 0;
326 uint32_t data_crc, crc;
327 struct ubi_vid_hdr *vh = NULL;
328 unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
329
330 if (sqnum2 == aeb->sqnum) {
331 /*
332 * This must be a really ancient UBI image which has been
333 * created before sequence numbers support has been added. At
334 * that times we used 32-bit LEB versions stored in logical
335 * eraseblocks. That was before UBI got into mainline. We do not
336 * support these images anymore. Well, those images still work,
337 * but only if no unclean reboots happened.
338 */
339 ubi_err("unsupported on-flash UBI format");
340 return -EINVAL;
341 }
342
343 /* Obviously the LEB with lower sequence counter is older */
344 second_is_newer = (sqnum2 > aeb->sqnum);
345
346 /*
347 * Now we know which copy is newer. If the copy flag of the PEB with
348 * newer version is not set, then we just return, otherwise we have to
349 * check data CRC. For the second PEB we already have the VID header,
350 * for the first one - we'll need to re-read it from flash.
351 *
352 * Note: this may be optimized so that we wouldn't read twice.
353 */
354
355 if (second_is_newer) {
356 if (!vid_hdr->copy_flag) {
357 /* It is not a copy, so it is newer */
358 dbg_bld("second PEB %d is newer, copy_flag is unset",
359 pnum);
360 return 1;
361 }
362 } else {
363 if (!aeb->copy_flag) {
364 /* It is not a copy, so it is newer */
365 dbg_bld("first PEB %d is newer, copy_flag is unset",
366 pnum);
367 return bitflips << 1;
368 }
369
370 vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
371 if (!vh)
372 return -ENOMEM;
373
374 pnum = aeb->pnum;
375 err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
376 if (err) {
377 if (err == UBI_IO_BITFLIPS)
378 bitflips = 1;
379 else {
380 ubi_err("VID of PEB %d header is bad, but it was OK earlier, err %d",
381 pnum, err);
382 if (err > 0)
383 err = -EIO;
384
385 goto out_free_vidh;
386 }
387 }
388
389 vid_hdr = vh;
390 }
391
392 /* Read the data of the copy and check the CRC */
393
394 len = be32_to_cpu(vid_hdr->data_size);
395
396 mutex_lock(&ubi->buf_mutex);
397 err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, len);
398 if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
399 goto out_unlock;
400
401 data_crc = be32_to_cpu(vid_hdr->data_crc);
402 crc = crc32(UBI_CRC32_INIT, ubi->peb_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 mutex_unlock(&ubi->buf_mutex);
414
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_unlock:
425 mutex_unlock(&ubi->buf_mutex);
426out_free_vidh:
427 ubi_free_vid_hdr(ubi, vh);
428 return err;
429}
430
431/**
432 * ubi_add_to_av - add used physical eraseblock to the attaching information.
433 * @ubi: UBI device description object
434 * @ai: attaching 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_add_to_av(struct ubi_device *ubi, struct ubi_attach_info *ai, int pnum,
448 int ec, const struct ubi_vid_hdr *vid_hdr, int bitflips)
449{
450 int err, vol_id, lnum;
451 unsigned long long sqnum;
452 struct ubi_ainf_volume *av;
453 struct ubi_ainf_peb *aeb;
454 struct rb_node **p, *parent = NULL;
455
456 vol_id = be32_to_cpu(vid_hdr->vol_id);
457 lnum = be32_to_cpu(vid_hdr->lnum);
458 sqnum = be64_to_cpu(vid_hdr->sqnum);
459
460 dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
461 pnum, vol_id, lnum, ec, sqnum, bitflips);
462
463 av = add_volume(ai, vol_id, pnum, vid_hdr);
464 if (IS_ERR(av))
465 return PTR_ERR(av);
466
467 if (ai->max_sqnum < sqnum)
468 ai->max_sqnum = sqnum;
469
470 /*
471 * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
472 * if this is the first instance of this logical eraseblock or not.
473 */
474 p = &av->root.rb_node;
475 while (*p) {
476 int cmp_res;
477
478 parent = *p;
479 aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
480 if (lnum != aeb->lnum) {
481 if (lnum < aeb->lnum)
482 p = &(*p)->rb_left;
483 else
484 p = &(*p)->rb_right;
485 continue;
486 }
487
488 /*
489 * There is already a physical eraseblock describing the same
490 * logical eraseblock present.
491 */
492
493 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, EC %d",
494 aeb->pnum, aeb->sqnum, aeb->ec);
495
496 /*
497 * Make sure that the logical eraseblocks have different
498 * sequence numbers. Otherwise the image is bad.
499 *
500 * However, if the sequence number is zero, we assume it must
501 * be an ancient UBI image from the era when UBI did not have
502 * sequence numbers. We still can attach these images, unless
503 * there is a need to distinguish between old and new
504 * eraseblocks, in which case we'll refuse the image in
505 * 'ubi_compare_lebs()'. In other words, we attach old clean
506 * images, but refuse attaching old images with duplicated
507 * logical eraseblocks because there was an unclean reboot.
508 */
509 if (aeb->sqnum == sqnum && sqnum != 0) {
510 ubi_err("two LEBs with same sequence number %llu",
511 sqnum);
512 ubi_dump_aeb(aeb, 0);
513 ubi_dump_vid_hdr(vid_hdr);
514 return -EINVAL;
515 }
516
517 /*
518 * Now we have to drop the older one and preserve the newer
519 * one.
520 */
521 cmp_res = ubi_compare_lebs(ubi, aeb, pnum, vid_hdr);
522 if (cmp_res < 0)
523 return cmp_res;
524
525 if (cmp_res & 1) {
526 /*
527 * This logical eraseblock is newer than the one
528 * found earlier.
529 */
530 err = validate_vid_hdr(vid_hdr, av, pnum);
531 if (err)
532 return err;
533
534 err = add_to_list(ai, aeb->pnum, aeb->vol_id,
535 aeb->lnum, aeb->ec, cmp_res & 4,
536 &ai->erase);
537 if (err)
538 return err;
539
540 aeb->ec = ec;
541 aeb->pnum = pnum;
542 aeb->vol_id = vol_id;
543 aeb->lnum = lnum;
544 aeb->scrub = ((cmp_res & 2) || bitflips);
545 aeb->copy_flag = vid_hdr->copy_flag;
546 aeb->sqnum = sqnum;
547
548 if (av->highest_lnum == lnum)
549 av->last_data_size =
550 be32_to_cpu(vid_hdr->data_size);
551
552 return 0;
553 } else {
554 /*
555 * This logical eraseblock is older than the one found
556 * previously.
557 */
558 return add_to_list(ai, pnum, vol_id, lnum, ec,
559 cmp_res & 4, &ai->erase);
560 }
561 }
562
563 /*
564 * We've met this logical eraseblock for the first time, add it to the
565 * attaching information.
566 */
567
568 err = validate_vid_hdr(vid_hdr, av, pnum);
569 if (err)
570 return err;
571
572 aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL);
573 if (!aeb)
574 return -ENOMEM;
575
576 aeb->ec = ec;
577 aeb->pnum = pnum;
578 aeb->vol_id = vol_id;
579 aeb->lnum = lnum;
580 aeb->scrub = bitflips;
581 aeb->copy_flag = vid_hdr->copy_flag;
582 aeb->sqnum = sqnum;
583
584 if (av->highest_lnum <= lnum) {
585 av->highest_lnum = lnum;
586 av->last_data_size = be32_to_cpu(vid_hdr->data_size);
587 }
588
589 av->leb_count += 1;
590 rb_link_node(&aeb->u.rb, parent, p);
591 rb_insert_color(&aeb->u.rb, &av->root);
592 return 0;
593}
594
595/**
596 * ubi_find_av - find volume in the attaching information.
597 * @ai: attaching information
598 * @vol_id: the requested volume ID
599 *
600 * This function returns a pointer to the volume description or %NULL if there
601 * are no data about this volume in the attaching information.
602 */
603struct ubi_ainf_volume *ubi_find_av(const struct ubi_attach_info *ai,
604 int vol_id)
605{
606 struct ubi_ainf_volume *av;
607 struct rb_node *p = ai->volumes.rb_node;
608
609 while (p) {
610 av = rb_entry(p, struct ubi_ainf_volume, rb);
611
612 if (vol_id == av->vol_id)
613 return av;
614
615 if (vol_id > av->vol_id)
616 p = p->rb_left;
617 else
618 p = p->rb_right;
619 }
620
621 return NULL;
622}
623
624/**
625 * ubi_remove_av - delete attaching information about a volume.
626 * @ai: attaching information
627 * @av: the volume attaching information to delete
628 */
629void ubi_remove_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
630{
631 struct rb_node *rb;
632 struct ubi_ainf_peb *aeb;
633
634 dbg_bld("remove attaching information about volume %d", av->vol_id);
635
636 while ((rb = rb_first(&av->root))) {
637 aeb = rb_entry(rb, struct ubi_ainf_peb, u.rb);
638 rb_erase(&aeb->u.rb, &av->root);
639 list_add_tail(&aeb->u.list, &ai->erase);
640 }
641
642 rb_erase(&av->rb, &ai->volumes);
643 kfree(av);
644 ai->vols_found -= 1;
645}
646
647/**
648 * early_erase_peb - erase a physical eraseblock.
649 * @ubi: UBI device description object
650 * @ai: attaching information
651 * @pnum: physical eraseblock number to erase;
652 * @ec: erase counter value to write (%UBI_UNKNOWN if it is unknown)
653 *
654 * This function erases physical eraseblock 'pnum', and writes the erase
655 * counter header to it. This function should only be used on UBI device
656 * initialization stages, when the EBA sub-system had not been yet initialized.
657 * This function returns zero in case of success and a negative error code in
658 * case of failure.
659 */
660static int early_erase_peb(struct ubi_device *ubi,
661 const struct ubi_attach_info *ai, int pnum, int ec)
662{
663 int err;
664 struct ubi_ec_hdr *ec_hdr;
665
666 if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
667 /*
668 * Erase counter overflow. Upgrade UBI and use 64-bit
669 * erase counters internally.
670 */
671 ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
672 return -EINVAL;
673 }
674
675 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
676 if (!ec_hdr)
677 return -ENOMEM;
678
679 ec_hdr->ec = cpu_to_be64(ec);
680
681 err = ubi_io_sync_erase(ubi, pnum, 0);
682 if (err < 0)
683 goto out_free;
684
685 err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
686
687out_free:
688 kfree(ec_hdr);
689 return err;
690}
691
692/**
693 * ubi_early_get_peb - get a free physical eraseblock.
694 * @ubi: UBI device description object
695 * @ai: attaching information
696 *
697 * This function returns a free physical eraseblock. It is supposed to be
698 * called on the UBI initialization stages when the wear-leveling sub-system is
699 * not initialized yet. This function picks a physical eraseblocks from one of
700 * the lists, writes the EC header if it is needed, and removes it from the
701 * list.
702 *
703 * This function returns a pointer to the "aeb" of the found free PEB in case
704 * of success and an error code in case of failure.
705 */
706struct ubi_ainf_peb *ubi_early_get_peb(struct ubi_device *ubi,
707 struct ubi_attach_info *ai)
708{
709 int err = 0;
710 struct ubi_ainf_peb *aeb, *tmp_aeb;
711
712 if (!list_empty(&ai->free)) {
713 aeb = list_entry(ai->free.next, struct ubi_ainf_peb, u.list);
714 list_del(&aeb->u.list);
715 dbg_bld("return free PEB %d, EC %d", aeb->pnum, aeb->ec);
716 return aeb;
717 }
718
719 /*
720 * We try to erase the first physical eraseblock from the erase list
721 * and pick it if we succeed, or try to erase the next one if not. And
722 * so forth. We don't want to take care about bad eraseblocks here -
723 * they'll be handled later.
724 */
725 list_for_each_entry_safe(aeb, tmp_aeb, &ai->erase, u.list) {
726 if (aeb->ec == UBI_UNKNOWN)
727 aeb->ec = ai->mean_ec;
728
729 err = early_erase_peb(ubi, ai, aeb->pnum, aeb->ec+1);
730 if (err)
731 continue;
732
733 aeb->ec += 1;
734 list_del(&aeb->u.list);
735 dbg_bld("return PEB %d, EC %d", aeb->pnum, aeb->ec);
736 return aeb;
737 }
738
739 ubi_err("no free eraseblocks");
740 return ERR_PTR(-ENOSPC);
741}
742
743/**
744 * check_corruption - check the data area of PEB.
745 * @ubi: UBI device description object
746 * @vid_hdr: the (corrupted) VID header of this PEB
747 * @pnum: the physical eraseblock number to check
748 *
749 * This is a helper function which is used to distinguish between VID header
750 * corruptions caused by power cuts and other reasons. If the PEB contains only
751 * 0xFF bytes in the data area, the VID header is most probably corrupted
752 * because of a power cut (%0 is returned in this case). Otherwise, it was
753 * probably corrupted for some other reasons (%1 is returned in this case). A
754 * negative error code is returned if a read error occurred.
755 *
756 * If the corruption reason was a power cut, UBI can safely erase this PEB.
757 * Otherwise, it should preserve it to avoid possibly destroying important
758 * information.
759 */
760static int check_corruption(struct ubi_device *ubi, struct ubi_vid_hdr *vid_hdr,
761 int pnum)
762{
763 int err;
764
765 mutex_lock(&ubi->buf_mutex);
766 memset(ubi->peb_buf, 0x00, ubi->leb_size);
767
768 err = ubi_io_read(ubi, ubi->peb_buf, pnum, ubi->leb_start,
769 ubi->leb_size);
770 if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err)) {
771 /*
772 * Bit-flips or integrity errors while reading the data area.
773 * It is difficult to say for sure what type of corruption is
774 * this, but presumably a power cut happened while this PEB was
775 * erased, so it became unstable and corrupted, and should be
776 * erased.
777 */
778 err = 0;
779 goto out_unlock;
780 }
781
782 if (err)
783 goto out_unlock;
784
785 if (ubi_check_pattern(ubi->peb_buf, 0xFF, ubi->leb_size))
786 goto out_unlock;
787
788 ubi_err("PEB %d contains corrupted VID header, and the data does not contain all 0xFF",
789 pnum);
790 ubi_err("this may be a non-UBI PEB or a severe VID header corruption which requires manual inspection");
791 ubi_dump_vid_hdr(vid_hdr);
792 pr_err("hexdump of PEB %d offset %d, length %d",
793 pnum, ubi->leb_start, ubi->leb_size);
794 ubi_dbg_print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
795 ubi->peb_buf, ubi->leb_size, 1);
796 err = 1;
797
798out_unlock:
799 mutex_unlock(&ubi->buf_mutex);
800 return err;
801}
802
803/**
804 * scan_peb - scan and process UBI headers of a PEB.
805 * @ubi: UBI device description object
806 * @ai: attaching information
807 * @pnum: the physical eraseblock number
808 * @vid: The volume ID of the found volume will be stored in this pointer
809 * @sqnum: The sqnum of the found volume will be stored in this pointer
810 *
811 * This function reads UBI headers of PEB @pnum, checks them, and adds
812 * information about this PEB to the corresponding list or RB-tree in the
813 * "attaching info" structure. Returns zero if the physical eraseblock was
814 * successfully handled and a negative error code in case of failure.
815 */
816static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
817 int pnum, int *vid, unsigned long long *sqnum)
818{
819 long long uninitialized_var(ec);
820 int err, bitflips = 0, vol_id = -1, ec_err = 0;
821
822 dbg_bld("scan PEB %d", pnum);
823
824 /* Skip bad physical eraseblocks */
825 err = ubi_io_is_bad(ubi, pnum);
826 if (err < 0)
827 return err;
828 else if (err) {
829 ai->bad_peb_count += 1;
830 return 0;
831 }
832
833 err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
834 if (err < 0)
835 return err;
836 switch (err) {
837 case 0:
838 break;
839 case UBI_IO_BITFLIPS:
840 bitflips = 1;
841 break;
842 case UBI_IO_FF:
843 ai->empty_peb_count += 1;
844 return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
845 UBI_UNKNOWN, 0, &ai->erase);
846 case UBI_IO_FF_BITFLIPS:
847 ai->empty_peb_count += 1;
848 return add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
849 UBI_UNKNOWN, 1, &ai->erase);
850 case UBI_IO_BAD_HDR_EBADMSG:
851 case UBI_IO_BAD_HDR:
852 /*
853 * We have to also look at the VID header, possibly it is not
854 * corrupted. Set %bitflips flag in order to make this PEB be
855 * moved and EC be re-created.
856 */
857 ec_err = err;
858 ec = UBI_UNKNOWN;
859 bitflips = 1;
860 break;
861 default:
862 ubi_err("'ubi_io_read_ec_hdr()' returned unknown code %d", err);
863 return -EINVAL;
864 }
865
866 if (!ec_err) {
867 int image_seq;
868
869 /* Make sure UBI version is OK */
870 if (ech->version != UBI_VERSION) {
871 ubi_err("this UBI version is %d, image version is %d",
872 UBI_VERSION, (int)ech->version);
873 return -EINVAL;
874 }
875
876 ec = be64_to_cpu(ech->ec);
877 if (ec > UBI_MAX_ERASECOUNTER) {
878 /*
879 * Erase counter overflow. The EC headers have 64 bits
880 * reserved, but we anyway make use of only 31 bit
881 * values, as this seems to be enough for any existing
882 * flash. Upgrade UBI and use 64-bit erase counters
883 * internally.
884 */
885 ubi_err("erase counter overflow, max is %d",
886 UBI_MAX_ERASECOUNTER);
887 ubi_dump_ec_hdr(ech);
888 return -EINVAL;
889 }
890
891 /*
892 * Make sure that all PEBs have the same image sequence number.
893 * This allows us to detect situations when users flash UBI
894 * images incorrectly, so that the flash has the new UBI image
895 * and leftovers from the old one. This feature was added
896 * relatively recently, and the sequence number was always
897 * zero, because old UBI implementations always set it to zero.
898 * For this reasons, we do not panic if some PEBs have zero
899 * sequence number, while other PEBs have non-zero sequence
900 * number.
901 */
902 image_seq = be32_to_cpu(ech->image_seq);
903 if (!ubi->image_seq)
904 ubi->image_seq = image_seq;
905 if (image_seq && ubi->image_seq != image_seq) {
906 ubi_err("bad image sequence number %d in PEB %d, expected %d",
907 image_seq, pnum, ubi->image_seq);
908 ubi_dump_ec_hdr(ech);
909 return -EINVAL;
910 }
911 }
912
913 /* OK, we've done with the EC header, let's look at the VID header */
914
915 err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
916 if (err < 0)
917 return err;
918 switch (err) {
919 case 0:
920 break;
921 case UBI_IO_BITFLIPS:
922 bitflips = 1;
923 break;
924 case UBI_IO_BAD_HDR_EBADMSG:
925 if (ec_err == UBI_IO_BAD_HDR_EBADMSG)
926 /*
927 * Both EC and VID headers are corrupted and were read
928 * with data integrity error, probably this is a bad
929 * PEB, bit it is not marked as bad yet. This may also
930 * be a result of power cut during erasure.
931 */
932 ai->maybe_bad_peb_count += 1;
933 case UBI_IO_BAD_HDR:
934 if (ec_err)
935 /*
936 * Both headers are corrupted. There is a possibility
937 * that this a valid UBI PEB which has corresponding
938 * LEB, but the headers are corrupted. However, it is
939 * impossible to distinguish it from a PEB which just
940 * contains garbage because of a power cut during erase
941 * operation. So we just schedule this PEB for erasure.
942 *
943 * Besides, in case of NOR flash, we deliberately
944 * corrupt both headers because NOR flash erasure is
945 * slow and can start from the end.
946 */
947 err = 0;
948 else
949 /*
950 * The EC was OK, but the VID header is corrupted. We
951 * have to check what is in the data area.
952 */
953 err = check_corruption(ubi, vidh, pnum);
954
955 if (err < 0)
956 return err;
957 else if (!err)
958 /* This corruption is caused by a power cut */
959 err = add_to_list(ai, pnum, UBI_UNKNOWN,
960 UBI_UNKNOWN, ec, 1, &ai->erase);
961 else
962 /* This is an unexpected corruption */
963 err = add_corrupted(ai, pnum, ec);
964 if (err)
965 return err;
966 goto adjust_mean_ec;
967 case UBI_IO_FF_BITFLIPS:
968 err = add_to_list(ai, pnum, UBI_UNKNOWN, UBI_UNKNOWN,
969 ec, 1, &ai->erase);
970 if (err)
971 return err;
972 goto adjust_mean_ec;
973 case UBI_IO_FF:
974 if (ec_err || bitflips)
975 err = add_to_list(ai, pnum, UBI_UNKNOWN,
976 UBI_UNKNOWN, ec, 1, &ai->erase);
977 else
978 err = add_to_list(ai, pnum, UBI_UNKNOWN,
979 UBI_UNKNOWN, ec, 0, &ai->free);
980 if (err)
981 return err;
982 goto adjust_mean_ec;
983 default:
984 ubi_err("'ubi_io_read_vid_hdr()' returned unknown code %d",
985 err);
986 return -EINVAL;
987 }
988
989 vol_id = be32_to_cpu(vidh->vol_id);
990 if (vid)
991 *vid = vol_id;
992 if (sqnum)
993 *sqnum = be64_to_cpu(vidh->sqnum);
994 if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
995 int lnum = be32_to_cpu(vidh->lnum);
996
997 /* Unsupported internal volume */
998 switch (vidh->compat) {
999 case UBI_COMPAT_DELETE:
1000 if (vol_id != UBI_FM_SB_VOLUME_ID
1001 && vol_id != UBI_FM_DATA_VOLUME_ID) {
1002 ubi_msg("\"delete\" compatible internal volume %d:%d found, will remove it",
1003 vol_id, lnum);
1004 }
1005 err = add_to_list(ai, pnum, vol_id, lnum,
1006 ec, 1, &ai->erase);
1007 if (err)
1008 return err;
1009 return 0;
1010
1011 case UBI_COMPAT_RO:
1012 ubi_msg("read-only compatible internal volume %d:%d found, switch to read-only mode",
1013 vol_id, lnum);
1014 ubi->ro_mode = 1;
1015 break;
1016
1017 case UBI_COMPAT_PRESERVE:
1018 ubi_msg("\"preserve\" compatible internal volume %d:%d found",
1019 vol_id, lnum);
1020 err = add_to_list(ai, pnum, vol_id, lnum,
1021 ec, 0, &ai->alien);
1022 if (err)
1023 return err;
1024 return 0;
1025
1026 case UBI_COMPAT_REJECT:
1027 ubi_err("incompatible internal volume %d:%d found",
1028 vol_id, lnum);
1029 return -EINVAL;
1030 }
1031 }
1032
1033 if (ec_err)
1034 ubi_warn("valid VID header but corrupted EC header at PEB %d",
1035 pnum);
1036 err = ubi_add_to_av(ubi, ai, pnum, ec, vidh, bitflips);
1037 if (err)
1038 return err;
1039
1040adjust_mean_ec:
1041 if (!ec_err) {
1042 ai->ec_sum += ec;
1043 ai->ec_count += 1;
1044 if (ec > ai->max_ec)
1045 ai->max_ec = ec;
1046 if (ec < ai->min_ec)
1047 ai->min_ec = ec;
1048 }
1049
1050 return 0;
1051}
1052
1053/**
1054 * late_analysis - analyze the overall situation with PEB.
1055 * @ubi: UBI device description object
1056 * @ai: attaching information
1057 *
1058 * This is a helper function which takes a look what PEBs we have after we
1059 * gather information about all of them ("ai" is compete). It decides whether
1060 * the flash is empty and should be formatted of whether there are too many
1061 * corrupted PEBs and we should not attach this MTD device. Returns zero if we
1062 * should proceed with attaching the MTD device, and %-EINVAL if we should not.
1063 */
1064static int late_analysis(struct ubi_device *ubi, struct ubi_attach_info *ai)
1065{
1066 struct ubi_ainf_peb *aeb;
1067 int max_corr, peb_count;
1068
1069 peb_count = ubi->peb_count - ai->bad_peb_count - ai->alien_peb_count;
1070 max_corr = peb_count / 20 ?: 8;
1071
1072 /*
1073 * Few corrupted PEBs is not a problem and may be just a result of
1074 * unclean reboots. However, many of them may indicate some problems
1075 * with the flash HW or driver.
1076 */
1077 if (ai->corr_peb_count) {
1078 ubi_err("%d PEBs are corrupted and preserved",
1079 ai->corr_peb_count);
1080 pr_err("Corrupted PEBs are:");
1081 list_for_each_entry(aeb, &ai->corr, u.list)
1082 pr_cont(" %d", aeb->pnum);
1083 pr_cont("\n");
1084
1085 /*
1086 * If too many PEBs are corrupted, we refuse attaching,
1087 * otherwise, only print a warning.
1088 */
1089 if (ai->corr_peb_count >= max_corr) {
1090 ubi_err("too many corrupted PEBs, refusing");
1091 return -EINVAL;
1092 }
1093 }
1094
1095 if (ai->empty_peb_count + ai->maybe_bad_peb_count == peb_count) {
1096 /*
1097 * All PEBs are empty, or almost all - a couple PEBs look like
1098 * they may be bad PEBs which were not marked as bad yet.
1099 *
1100 * This piece of code basically tries to distinguish between
1101 * the following situations:
1102 *
1103 * 1. Flash is empty, but there are few bad PEBs, which are not
1104 * marked as bad so far, and which were read with error. We
1105 * want to go ahead and format this flash. While formatting,
1106 * the faulty PEBs will probably be marked as bad.
1107 *
1108 * 2. Flash contains non-UBI data and we do not want to format
1109 * it and destroy possibly important information.
1110 */
1111 if (ai->maybe_bad_peb_count <= 2) {
1112 ai->is_empty = 1;
1113 ubi_msg("empty MTD device detected");
1114 get_random_bytes(&ubi->image_seq,
1115 sizeof(ubi->image_seq));
1116 } else {
1117 ubi_err("MTD device is not UBI-formatted and possibly contains non-UBI data - refusing it");
1118 return -EINVAL;
1119 }
1120
1121 }
1122
1123 return 0;
1124}
1125
1126/**
1127 * destroy_av - free volume attaching information.
1128 * @av: volume attaching information
1129 * @ai: attaching information
1130 *
1131 * This function destroys the volume attaching information.
1132 */
1133static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
1134{
1135 struct ubi_ainf_peb *aeb;
1136 struct rb_node *this = av->root.rb_node;
1137
1138 while (this) {
1139 if (this->rb_left)
1140 this = this->rb_left;
1141 else if (this->rb_right)
1142 this = this->rb_right;
1143 else {
1144 aeb = rb_entry(this, struct ubi_ainf_peb, u.rb);
1145 this = rb_parent(this);
1146 if (this) {
1147 if (this->rb_left == &aeb->u.rb)
1148 this->rb_left = NULL;
1149 else
1150 this->rb_right = NULL;
1151 }
1152
1153 kmem_cache_free(ai->aeb_slab_cache, aeb);
1154 }
1155 }
1156 kfree(av);
1157}
1158
1159/**
1160 * destroy_ai - destroy attaching information.
1161 * @ai: attaching information
1162 */
1163static void destroy_ai(struct ubi_attach_info *ai)
1164{
1165 struct ubi_ainf_peb *aeb, *aeb_tmp;
1166 struct ubi_ainf_volume *av;
1167 struct rb_node *rb;
1168
1169 list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, u.list) {
1170 list_del(&aeb->u.list);
1171 kmem_cache_free(ai->aeb_slab_cache, aeb);
1172 }
1173 list_for_each_entry_safe(aeb, aeb_tmp, &ai->erase, u.list) {
1174 list_del(&aeb->u.list);
1175 kmem_cache_free(ai->aeb_slab_cache, aeb);
1176 }
1177 list_for_each_entry_safe(aeb, aeb_tmp, &ai->corr, u.list) {
1178 list_del(&aeb->u.list);
1179 kmem_cache_free(ai->aeb_slab_cache, aeb);
1180 }
1181 list_for_each_entry_safe(aeb, aeb_tmp, &ai->free, u.list) {
1182 list_del(&aeb->u.list);
1183 kmem_cache_free(ai->aeb_slab_cache, aeb);
1184 }
1185
1186 /* Destroy the volume RB-tree */
1187 rb = ai->volumes.rb_node;
1188 while (rb) {
1189 if (rb->rb_left)
1190 rb = rb->rb_left;
1191 else if (rb->rb_right)
1192 rb = rb->rb_right;
1193 else {
1194 av = rb_entry(rb, struct ubi_ainf_volume, rb);
1195
1196 rb = rb_parent(rb);
1197 if (rb) {
1198 if (rb->rb_left == &av->rb)
1199 rb->rb_left = NULL;
1200 else
1201 rb->rb_right = NULL;
1202 }
1203
1204 destroy_av(ai, av);
1205 }
1206 }
1207
1208 if (ai->aeb_slab_cache)
1209 kmem_cache_destroy(ai->aeb_slab_cache);
1210
1211 kfree(ai);
1212}
1213
1214/**
1215 * scan_all - scan entire MTD device.
1216 * @ubi: UBI device description object
1217 * @ai: attach info object
1218 * @start: start scanning at this PEB
1219 *
1220 * This function does full scanning of an MTD device and returns complete
1221 * information about it in form of a "struct ubi_attach_info" object. In case
1222 * of failure, an error code is returned.
1223 */
1224static int scan_all(struct ubi_device *ubi, struct ubi_attach_info *ai,
1225 int start)
1226{
1227 int err, pnum;
1228 struct rb_node *rb1, *rb2;
1229 struct ubi_ainf_volume *av;
1230 struct ubi_ainf_peb *aeb;
1231
1232 err = -ENOMEM;
1233
1234 ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1235 if (!ech)
1236 return err;
1237
1238 vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
1239 if (!vidh)
1240 goto out_ech;
1241
1242 for (pnum = start; pnum < ubi->peb_count; pnum++) {
1243 cond_resched();
1244
1245 dbg_gen("process PEB %d", pnum);
1246 err = scan_peb(ubi, ai, pnum, NULL, NULL);
1247 if (err < 0)
1248 goto out_vidh;
1249 }
1250
1251 ubi_msg("scanning is finished");
1252
1253 /* Calculate mean erase counter */
1254 if (ai->ec_count)
1255 ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count);
1256
1257 err = late_analysis(ubi, ai);
1258 if (err)
1259 goto out_vidh;
1260
1261 /*
1262 * In case of unknown erase counter we use the mean erase counter
1263 * value.
1264 */
1265 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1266 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
1267 if (aeb->ec == UBI_UNKNOWN)
1268 aeb->ec = ai->mean_ec;
1269 }
1270
1271 list_for_each_entry(aeb, &ai->free, u.list) {
1272 if (aeb->ec == UBI_UNKNOWN)
1273 aeb->ec = ai->mean_ec;
1274 }
1275
1276 list_for_each_entry(aeb, &ai->corr, u.list)
1277 if (aeb->ec == UBI_UNKNOWN)
1278 aeb->ec = ai->mean_ec;
1279
1280 list_for_each_entry(aeb, &ai->erase, u.list)
1281 if (aeb->ec == UBI_UNKNOWN)
1282 aeb->ec = ai->mean_ec;
1283
1284 err = self_check_ai(ubi, ai);
1285 if (err)
1286 goto out_vidh;
1287
1288 ubi_free_vid_hdr(ubi, vidh);
1289 kfree(ech);
1290
1291 return 0;
1292
1293out_vidh:
1294 ubi_free_vid_hdr(ubi, vidh);
1295out_ech:
1296 kfree(ech);
1297 return err;
1298}
1299
1300#ifdef CONFIG_MTD_UBI_FASTMAP
1301
1302/**
1303 * scan_fastmap - try to find a fastmap and attach from it.
1304 * @ubi: UBI device description object
1305 * @ai: attach info object
1306 *
1307 * Returns 0 on success, negative return values indicate an internal
1308 * error.
1309 * UBI_NO_FASTMAP denotes that no fastmap was found.
1310 * UBI_BAD_FASTMAP denotes that the found fastmap was invalid.
1311 */
1312static int scan_fast(struct ubi_device *ubi, struct ubi_attach_info *ai)
1313{
1314 int err, pnum, fm_anchor = -1;
1315 unsigned long long max_sqnum = 0;
1316
1317 err = -ENOMEM;
1318
1319 ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1320 if (!ech)
1321 goto out;
1322
1323 vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
1324 if (!vidh)
1325 goto out_ech;
1326
1327 for (pnum = 0; pnum < UBI_FM_MAX_START; pnum++) {
1328 int vol_id = -1;
1329 unsigned long long sqnum = -1;
1330 cond_resched();
1331
1332 dbg_gen("process PEB %d", pnum);
1333 err = scan_peb(ubi, ai, pnum, &vol_id, &sqnum);
1334 if (err < 0)
1335 goto out_vidh;
1336
1337 if (vol_id == UBI_FM_SB_VOLUME_ID && sqnum > max_sqnum) {
1338 max_sqnum = sqnum;
1339 fm_anchor = pnum;
1340 }
1341 }
1342
1343 ubi_free_vid_hdr(ubi, vidh);
1344 kfree(ech);
1345
1346 if (fm_anchor < 0)
1347 return UBI_NO_FASTMAP;
1348
1349 return ubi_scan_fastmap(ubi, ai, fm_anchor);
1350
1351out_vidh:
1352 ubi_free_vid_hdr(ubi, vidh);
1353out_ech:
1354 kfree(ech);
1355out:
1356 return err;
1357}
1358
1359#endif
1360
1361static struct ubi_attach_info *alloc_ai(const char *slab_name)
1362{
1363 struct ubi_attach_info *ai;
1364
1365 ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL);
1366 if (!ai)
1367 return ai;
1368
1369 INIT_LIST_HEAD(&ai->corr);
1370 INIT_LIST_HEAD(&ai->free);
1371 INIT_LIST_HEAD(&ai->erase);
1372 INIT_LIST_HEAD(&ai->alien);
1373 ai->volumes = RB_ROOT;
1374 ai->aeb_slab_cache = kmem_cache_create(slab_name,
1375 sizeof(struct ubi_ainf_peb),
1376 0, 0, NULL);
1377 if (!ai->aeb_slab_cache) {
1378 kfree(ai);
1379 ai = NULL;
1380 }
1381
1382 return ai;
1383}
1384
1385/**
1386 * ubi_attach - attach an MTD device.
1387 * @ubi: UBI device descriptor
1388 * @force_scan: if set to non-zero attach by scanning
1389 *
1390 * This function returns zero in case of success and a negative error code in
1391 * case of failure.
1392 */
1393int ubi_attach(struct ubi_device *ubi, int force_scan)
1394{
1395 int err;
1396 struct ubi_attach_info *ai;
1397
1398 ai = alloc_ai("ubi_aeb_slab_cache");
1399 if (!ai)
1400 return -ENOMEM;
1401
1402#ifdef CONFIG_MTD_UBI_FASTMAP
1403 /* On small flash devices we disable fastmap in any case. */
1404 if ((int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd) <= UBI_FM_MAX_START) {
1405 ubi->fm_disabled = 1;
1406 force_scan = 1;
1407 }
1408
1409 if (force_scan)
1410 err = scan_all(ubi, ai, 0);
1411 else {
1412 err = scan_fast(ubi, ai);
1413 if (err > 0) {
1414 if (err != UBI_NO_FASTMAP) {
1415 destroy_ai(ai);
1416 ai = alloc_ai("ubi_aeb_slab_cache2");
1417 if (!ai)
1418 return -ENOMEM;
1419
1420 err = scan_all(ubi, ai, 0);
1421 } else {
1422 err = scan_all(ubi, ai, UBI_FM_MAX_START);
1423 }
1424 }
1425 }
1426#else
1427 err = scan_all(ubi, ai, 0);
1428#endif
1429 if (err)
1430 goto out_ai;
1431
1432 ubi->bad_peb_count = ai->bad_peb_count;
1433 ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count;
1434 ubi->corr_peb_count = ai->corr_peb_count;
1435 ubi->max_ec = ai->max_ec;
1436 ubi->mean_ec = ai->mean_ec;
1437 dbg_gen("max. sequence number: %llu", ai->max_sqnum);
1438
1439 err = ubi_read_volume_table(ubi, ai);
1440 if (err)
1441 goto out_ai;
1442
1443 err = ubi_wl_init(ubi, ai);
1444 if (err)
1445 goto out_vtbl;
1446
1447 err = ubi_eba_init(ubi, ai);
1448 if (err)
1449 goto out_wl;
1450
1451#ifdef CONFIG_MTD_UBI_FASTMAP
1452 if (ubi->fm && ubi_dbg_chk_gen(ubi)) {
1453 struct ubi_attach_info *scan_ai;
1454
1455 scan_ai = alloc_ai("ubi_ckh_aeb_slab_cache");
1456 if (!scan_ai) {
1457 err = -ENOMEM;
1458 goto out_wl;
1459 }
1460
1461 err = scan_all(ubi, scan_ai, 0);
1462 if (err) {
1463 destroy_ai(scan_ai);
1464 goto out_wl;
1465 }
1466
1467 err = self_check_eba(ubi, ai, scan_ai);
1468 destroy_ai(scan_ai);
1469
1470 if (err)
1471 goto out_wl;
1472 }
1473#endif
1474
1475 destroy_ai(ai);
1476 return 0;
1477
1478out_wl:
1479 ubi_wl_close(ubi);
1480out_vtbl:
1481 ubi_free_internal_volumes(ubi);
1482 vfree(ubi->vtbl);
1483out_ai:
1484 destroy_ai(ai);
1485 return err;
1486}
1487
1488/**
1489 * self_check_ai - check the attaching information.
1490 * @ubi: UBI device description object
1491 * @ai: attaching information
1492 *
1493 * This function returns zero if the attaching information is all right, and a
1494 * negative error code if not or if an error occurred.
1495 */
1496static int self_check_ai(struct ubi_device *ubi, struct ubi_attach_info *ai)
1497{
1498 int pnum, err, vols_found = 0;
1499 struct rb_node *rb1, *rb2;
1500 struct ubi_ainf_volume *av;
1501 struct ubi_ainf_peb *aeb, *last_aeb;
1502 uint8_t *buf;
1503
1504 if (!ubi_dbg_chk_gen(ubi))
1505 return 0;
1506
1507 /*
1508 * At first, check that attaching information is OK.
1509 */
1510 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1511 int leb_count = 0;
1512
1513 cond_resched();
1514
1515 vols_found += 1;
1516
1517 if (ai->is_empty) {
1518 ubi_err("bad is_empty flag");
1519 goto bad_av;
1520 }
1521
1522 if (av->vol_id < 0 || av->highest_lnum < 0 ||
1523 av->leb_count < 0 || av->vol_type < 0 || av->used_ebs < 0 ||
1524 av->data_pad < 0 || av->last_data_size < 0) {
1525 ubi_err("negative values");
1526 goto bad_av;
1527 }
1528
1529 if (av->vol_id >= UBI_MAX_VOLUMES &&
1530 av->vol_id < UBI_INTERNAL_VOL_START) {
1531 ubi_err("bad vol_id");
1532 goto bad_av;
1533 }
1534
1535 if (av->vol_id > ai->highest_vol_id) {
1536 ubi_err("highest_vol_id is %d, but vol_id %d is there",
1537 ai->highest_vol_id, av->vol_id);
1538 goto out;
1539 }
1540
1541 if (av->vol_type != UBI_DYNAMIC_VOLUME &&
1542 av->vol_type != UBI_STATIC_VOLUME) {
1543 ubi_err("bad vol_type");
1544 goto bad_av;
1545 }
1546
1547 if (av->data_pad > ubi->leb_size / 2) {
1548 ubi_err("bad data_pad");
1549 goto bad_av;
1550 }
1551
1552 last_aeb = NULL;
1553 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1554 cond_resched();
1555
1556 last_aeb = aeb;
1557 leb_count += 1;
1558
1559 if (aeb->pnum < 0 || aeb->ec < 0) {
1560 ubi_err("negative values");
1561 goto bad_aeb;
1562 }
1563
1564 if (aeb->ec < ai->min_ec) {
1565 ubi_err("bad ai->min_ec (%d), %d found",
1566 ai->min_ec, aeb->ec);
1567 goto bad_aeb;
1568 }
1569
1570 if (aeb->ec > ai->max_ec) {
1571 ubi_err("bad ai->max_ec (%d), %d found",
1572 ai->max_ec, aeb->ec);
1573 goto bad_aeb;
1574 }
1575
1576 if (aeb->pnum >= ubi->peb_count) {
1577 ubi_err("too high PEB number %d, total PEBs %d",
1578 aeb->pnum, ubi->peb_count);
1579 goto bad_aeb;
1580 }
1581
1582 if (av->vol_type == UBI_STATIC_VOLUME) {
1583 if (aeb->lnum >= av->used_ebs) {
1584 ubi_err("bad lnum or used_ebs");
1585 goto bad_aeb;
1586 }
1587 } else {
1588 if (av->used_ebs != 0) {
1589 ubi_err("non-zero used_ebs");
1590 goto bad_aeb;
1591 }
1592 }
1593
1594 if (aeb->lnum > av->highest_lnum) {
1595 ubi_err("incorrect highest_lnum or lnum");
1596 goto bad_aeb;
1597 }
1598 }
1599
1600 if (av->leb_count != leb_count) {
1601 ubi_err("bad leb_count, %d objects in the tree",
1602 leb_count);
1603 goto bad_av;
1604 }
1605
1606 if (!last_aeb)
1607 continue;
1608
1609 aeb = last_aeb;
1610
1611 if (aeb->lnum != av->highest_lnum) {
1612 ubi_err("bad highest_lnum");
1613 goto bad_aeb;
1614 }
1615 }
1616
1617 if (vols_found != ai->vols_found) {
1618 ubi_err("bad ai->vols_found %d, should be %d",
1619 ai->vols_found, vols_found);
1620 goto out;
1621 }
1622
1623 /* Check that attaching information is correct */
1624 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1625 last_aeb = NULL;
1626 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1627 int vol_type;
1628
1629 cond_resched();
1630
1631 last_aeb = aeb;
1632
1633 err = ubi_io_read_vid_hdr(ubi, aeb->pnum, vidh, 1);
1634 if (err && err != UBI_IO_BITFLIPS) {
1635 ubi_err("VID header is not OK (%d)", err);
1636 if (err > 0)
1637 err = -EIO;
1638 return err;
1639 }
1640
1641 vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1642 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1643 if (av->vol_type != vol_type) {
1644 ubi_err("bad vol_type");
1645 goto bad_vid_hdr;
1646 }
1647
1648 if (aeb->sqnum != be64_to_cpu(vidh->sqnum)) {
1649 ubi_err("bad sqnum %llu", aeb->sqnum);
1650 goto bad_vid_hdr;
1651 }
1652
1653 if (av->vol_id != be32_to_cpu(vidh->vol_id)) {
1654 ubi_err("bad vol_id %d", av->vol_id);
1655 goto bad_vid_hdr;
1656 }
1657
1658 if (av->compat != vidh->compat) {
1659 ubi_err("bad compat %d", vidh->compat);
1660 goto bad_vid_hdr;
1661 }
1662
1663 if (aeb->lnum != be32_to_cpu(vidh->lnum)) {
1664 ubi_err("bad lnum %d", aeb->lnum);
1665 goto bad_vid_hdr;
1666 }
1667
1668 if (av->used_ebs != be32_to_cpu(vidh->used_ebs)) {
1669 ubi_err("bad used_ebs %d", av->used_ebs);
1670 goto bad_vid_hdr;
1671 }
1672
1673 if (av->data_pad != be32_to_cpu(vidh->data_pad)) {
1674 ubi_err("bad data_pad %d", av->data_pad);
1675 goto bad_vid_hdr;
1676 }
1677 }
1678
1679 if (!last_aeb)
1680 continue;
1681
1682 if (av->highest_lnum != be32_to_cpu(vidh->lnum)) {
1683 ubi_err("bad highest_lnum %d", av->highest_lnum);
1684 goto bad_vid_hdr;
1685 }
1686
1687 if (av->last_data_size != be32_to_cpu(vidh->data_size)) {
1688 ubi_err("bad last_data_size %d", av->last_data_size);
1689 goto bad_vid_hdr;
1690 }
1691 }
1692
1693 /*
1694 * Make sure that all the physical eraseblocks are in one of the lists
1695 * or trees.
1696 */
1697 buf = kzalloc(ubi->peb_count, GFP_KERNEL);
1698 if (!buf)
1699 return -ENOMEM;
1700
1701 for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1702 err = ubi_io_is_bad(ubi, pnum);
1703 if (err < 0) {
1704 kfree(buf);
1705 return err;
1706 } else if (err)
1707 buf[pnum] = 1;
1708 }
1709
1710 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb)
1711 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
1712 buf[aeb->pnum] = 1;
1713
1714 list_for_each_entry(aeb, &ai->free, u.list)
1715 buf[aeb->pnum] = 1;
1716
1717 list_for_each_entry(aeb, &ai->corr, u.list)
1718 buf[aeb->pnum] = 1;
1719
1720 list_for_each_entry(aeb, &ai->erase, u.list)
1721 buf[aeb->pnum] = 1;
1722
1723 list_for_each_entry(aeb, &ai->alien, u.list)
1724 buf[aeb->pnum] = 1;
1725
1726 err = 0;
1727 for (pnum = 0; pnum < ubi->peb_count; pnum++)
1728 if (!buf[pnum]) {
1729 ubi_err("PEB %d is not referred", pnum);
1730 err = 1;
1731 }
1732
1733 kfree(buf);
1734 if (err)
1735 goto out;
1736 return 0;
1737
1738bad_aeb:
1739 ubi_err("bad attaching information about LEB %d", aeb->lnum);
1740 ubi_dump_aeb(aeb, 0);
1741 ubi_dump_av(av);
1742 goto out;
1743
1744bad_av:
1745 ubi_err("bad attaching information about volume %d", av->vol_id);
1746 ubi_dump_av(av);
1747 goto out;
1748
1749bad_vid_hdr:
1750 ubi_err("bad attaching information about volume %d", av->vol_id);
1751 ubi_dump_av(av);
1752 ubi_dump_vid_hdr(vidh);
1753
1754out:
1755 dump_stack();
1756 return -EINVAL;
1757}