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