blob: f679f06494b6c79f355976826695693aead1efd0 [file] [log] [blame]
Kyungmin Parkc91a7192008-11-19 16:28:06 +01001/*
2 * Copyright (c) International Business Machines Corp., 2006
3 * Copyright (c) Nokia Corporation, 2006, 2007
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Author: Artem Bityutskiy (Битюцкий Артём)
20 */
21
22/*
23 * This file includes volume table manipulation code. The volume table is an
24 * on-flash table containing volume meta-data like name, number of reserved
25 * physical eraseblocks, type, etc. The volume table is stored in the so-called
26 * "layout volume".
27 *
28 * The layout volume is an internal volume which is organized as follows. It
29 * consists of two logical eraseblocks - LEB 0 and LEB 1. Each logical
30 * eraseblock stores one volume table copy, i.e. LEB 0 and LEB 1 duplicate each
31 * other. This redundancy guarantees robustness to unclean reboots. The volume
32 * table is basically an array of volume table records. Each record contains
33 * full information about the volume and protected by a CRC checksum.
34 *
35 * The volume table is changed, it is first changed in RAM. Then LEB 0 is
36 * erased, and the updated volume table is written back to LEB 0. Then same for
37 * LEB 1. This scheme guarantees recoverability from unclean reboots.
38 *
39 * In this UBI implementation the on-flash volume table does not contain any
40 * information about how many data static volumes contain. This information may
41 * be found from the scanning data.
42 *
43 * But it would still be beneficial to store this information in the volume
44 * table. For example, suppose we have a static volume X, and all its physical
45 * eraseblocks became bad for some reasons. Suppose we are attaching the
46 * corresponding MTD device, the scanning has found no logical eraseblocks
47 * corresponding to the volume X. According to the volume table volume X does
48 * exist. So we don't know whether it is just empty or all its physical
49 * eraseblocks went bad. So we cannot alarm the user about this corruption.
50 *
51 * The volume table also stores so-called "update marker", which is used for
52 * volume updates. Before updating the volume, the update marker is set, and
53 * after the update operation is finished, the update marker is cleared. So if
54 * the update operation was interrupted (e.g. by an unclean reboot) - the
55 * update marker is still there and we know that the volume's contents is
56 * damaged.
57 */
58
59#ifdef UBI_LINUX
60#include <linux/crc32.h>
61#include <linux/err.h>
62#include <asm/div64.h>
63#endif
64
65#include <ubi_uboot.h>
66#include "ubi.h"
67
68#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
69static void paranoid_vtbl_check(const struct ubi_device *ubi);
70#else
71#define paranoid_vtbl_check(ubi)
72#endif
73
74/* Empty volume table record */
75static struct ubi_vtbl_record empty_vtbl_record;
76
77/**
78 * ubi_change_vtbl_record - change volume table record.
79 * @ubi: UBI device description object
80 * @idx: table index to change
81 * @vtbl_rec: new volume table record
82 *
83 * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
84 * volume table record is written. The caller does not have to calculate CRC of
85 * the record as it is done by this function. Returns zero in case of success
86 * and a negative error code in case of failure.
87 */
88int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
89 struct ubi_vtbl_record *vtbl_rec)
90{
91 int i, err;
92 uint32_t crc;
93 struct ubi_volume *layout_vol;
94
95 ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
96 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
97
98 if (!vtbl_rec)
99 vtbl_rec = &empty_vtbl_record;
100 else {
101 crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC);
102 vtbl_rec->crc = cpu_to_be32(crc);
103 }
104
105 memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
106 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
107 err = ubi_eba_unmap_leb(ubi, layout_vol, i);
108 if (err)
109 return err;
110
111 err = ubi_eba_write_leb(ubi, layout_vol, i, ubi->vtbl, 0,
112 ubi->vtbl_size, UBI_LONGTERM);
113 if (err)
114 return err;
115 }
116
117 paranoid_vtbl_check(ubi);
118 return 0;
119}
120
121/**
122 * vtbl_check - check if volume table is not corrupted and contains sensible
123 * data.
124 * @ubi: UBI device description object
125 * @vtbl: volume table
126 *
127 * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
128 * and %-EINVAL if it contains inconsistent data.
129 */
130static int vtbl_check(const struct ubi_device *ubi,
131 const struct ubi_vtbl_record *vtbl)
132{
133 int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
134 int upd_marker, err;
135 uint32_t crc;
136 const char *name;
137
138 for (i = 0; i < ubi->vtbl_slots; i++) {
139 cond_resched();
140
141 reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
142 alignment = be32_to_cpu(vtbl[i].alignment);
143 data_pad = be32_to_cpu(vtbl[i].data_pad);
144 upd_marker = vtbl[i].upd_marker;
145 vol_type = vtbl[i].vol_type;
146 name_len = be16_to_cpu(vtbl[i].name_len);
147 name = (const char *) &vtbl[i].name[0];
148
149 crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
150 if (be32_to_cpu(vtbl[i].crc) != crc) {
151 ubi_err("bad CRC at record %u: %#08x, not %#08x",
152 i, crc, be32_to_cpu(vtbl[i].crc));
153 ubi_dbg_dump_vtbl_record(&vtbl[i], i);
154 return 1;
155 }
156
157 if (reserved_pebs == 0) {
158 if (memcmp(&vtbl[i], &empty_vtbl_record,
159 UBI_VTBL_RECORD_SIZE)) {
160 err = 2;
161 goto bad;
162 }
163 continue;
164 }
165
166 if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
167 name_len < 0) {
168 err = 3;
169 goto bad;
170 }
171
172 if (alignment > ubi->leb_size || alignment == 0) {
173 err = 4;
174 goto bad;
175 }
176
177 n = alignment & (ubi->min_io_size - 1);
178 if (alignment != 1 && n) {
179 err = 5;
180 goto bad;
181 }
182
183 n = ubi->leb_size % alignment;
184 if (data_pad != n) {
185 dbg_err("bad data_pad, has to be %d", n);
186 err = 6;
187 goto bad;
188 }
189
190 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
191 err = 7;
192 goto bad;
193 }
194
195 if (upd_marker != 0 && upd_marker != 1) {
196 err = 8;
197 goto bad;
198 }
199
200 if (reserved_pebs > ubi->good_peb_count) {
201 dbg_err("too large reserved_pebs, good PEBs %d",
202 ubi->good_peb_count);
203 err = 9;
204 goto bad;
205 }
206
207 if (name_len > UBI_VOL_NAME_MAX) {
208 err = 10;
209 goto bad;
210 }
211
212 if (name[0] == '\0') {
213 err = 11;
214 goto bad;
215 }
216
217 if (name_len != strnlen(name, name_len + 1)) {
218 err = 12;
219 goto bad;
220 }
221 }
222
223 /* Checks that all names are unique */
224 for (i = 0; i < ubi->vtbl_slots - 1; i++) {
225 for (n = i + 1; n < ubi->vtbl_slots; n++) {
226 int len1 = be16_to_cpu(vtbl[i].name_len);
227 int len2 = be16_to_cpu(vtbl[n].name_len);
228
229 if (len1 > 0 && len1 == len2 &&
230 !strncmp((char *)vtbl[i].name, (char *)vtbl[n].name, len1)) {
231 ubi_err("volumes %d and %d have the same name"
232 " \"%s\"", i, n, vtbl[i].name);
233 ubi_dbg_dump_vtbl_record(&vtbl[i], i);
234 ubi_dbg_dump_vtbl_record(&vtbl[n], n);
235 return -EINVAL;
236 }
237 }
238 }
239
240 return 0;
241
242bad:
243 ubi_err("volume table check failed: record %d, error %d", i, err);
244 ubi_dbg_dump_vtbl_record(&vtbl[i], i);
245 return -EINVAL;
246}
247
248/**
249 * create_vtbl - create a copy of volume table.
250 * @ubi: UBI device description object
251 * @si: scanning information
252 * @copy: number of the volume table copy
253 * @vtbl: contents of the volume table
254 *
255 * This function returns zero in case of success and a negative error code in
256 * case of failure.
257 */
258static int create_vtbl(struct ubi_device *ubi, struct ubi_scan_info *si,
259 int copy, void *vtbl)
260{
261 int err, tries = 0;
262 static struct ubi_vid_hdr *vid_hdr;
263 struct ubi_scan_volume *sv;
264 struct ubi_scan_leb *new_seb, *old_seb = NULL;
265
266 ubi_msg("create volume table (copy #%d)", copy + 1);
267
268 vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
269 if (!vid_hdr)
270 return -ENOMEM;
271
272 /*
273 * Check if there is a logical eraseblock which would have to contain
274 * this volume table copy was found during scanning. It has to be wiped
275 * out.
276 */
277 sv = ubi_scan_find_sv(si, UBI_LAYOUT_VOLUME_ID);
278 if (sv)
279 old_seb = ubi_scan_find_seb(sv, copy);
280
281retry:
282 new_seb = ubi_scan_get_free_peb(ubi, si);
283 if (IS_ERR(new_seb)) {
284 err = PTR_ERR(new_seb);
285 goto out_free;
286 }
287
288 vid_hdr->vol_type = UBI_VID_DYNAMIC;
289 vid_hdr->vol_id = cpu_to_be32(UBI_LAYOUT_VOLUME_ID);
290 vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT;
291 vid_hdr->data_size = vid_hdr->used_ebs =
292 vid_hdr->data_pad = cpu_to_be32(0);
293 vid_hdr->lnum = cpu_to_be32(copy);
294 vid_hdr->sqnum = cpu_to_be64(++si->max_sqnum);
295 vid_hdr->leb_ver = cpu_to_be32(old_seb ? old_seb->leb_ver + 1: 0);
296
297 /* The EC header is already there, write the VID header */
298 err = ubi_io_write_vid_hdr(ubi, new_seb->pnum, vid_hdr);
299 if (err)
300 goto write_error;
301
302 /* Write the layout volume contents */
303 err = ubi_io_write_data(ubi, vtbl, new_seb->pnum, 0, ubi->vtbl_size);
304 if (err)
305 goto write_error;
306
307 /*
308 * And add it to the scanning information. Don't delete the old
309 * @old_seb as it will be deleted and freed in 'ubi_scan_add_used()'.
310 */
311 err = ubi_scan_add_used(ubi, si, new_seb->pnum, new_seb->ec,
312 vid_hdr, 0);
313 kfree(new_seb);
314 ubi_free_vid_hdr(ubi, vid_hdr);
315 return err;
316
317write_error:
318 if (err == -EIO && ++tries <= 5) {
319 /*
320 * Probably this physical eraseblock went bad, try to pick
321 * another one.
322 */
323 list_add_tail(&new_seb->u.list, &si->corr);
324 goto retry;
325 }
326 kfree(new_seb);
327out_free:
328 ubi_free_vid_hdr(ubi, vid_hdr);
329 return err;
330
331}
332
333/**
334 * process_lvol - process the layout volume.
335 * @ubi: UBI device description object
336 * @si: scanning information
337 * @sv: layout volume scanning information
338 *
339 * This function is responsible for reading the layout volume, ensuring it is
340 * not corrupted, and recovering from corruptions if needed. Returns volume
341 * table in case of success and a negative error code in case of failure.
342 */
343static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
344 struct ubi_scan_info *si,
345 struct ubi_scan_volume *sv)
346{
347 int err;
348 struct rb_node *rb;
349 struct ubi_scan_leb *seb;
350 struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL };
351 int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1};
352
353 /*
354 * UBI goes through the following steps when it changes the layout
355 * volume:
356 * a. erase LEB 0;
357 * b. write new data to LEB 0;
358 * c. erase LEB 1;
359 * d. write new data to LEB 1.
360 *
361 * Before the change, both LEBs contain the same data.
362 *
363 * Due to unclean reboots, the contents of LEB 0 may be lost, but there
364 * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not.
365 * Similarly, LEB 1 may be lost, but there should be LEB 0. And
366 * finally, unclean reboots may result in a situation when neither LEB
367 * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB
368 * 0 contains more recent information.
369 *
370 * So the plan is to first check LEB 0. Then
371 * a. if LEB 0 is OK, it must be containing the most resent data; then
372 * we compare it with LEB 1, and if they are different, we copy LEB
373 * 0 to LEB 1;
374 * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1
375 * to LEB 0.
376 */
377
378 dbg_msg("check layout volume");
379
380 /* Read both LEB 0 and LEB 1 into memory */
381 ubi_rb_for_each_entry(rb, seb, &sv->root, u.rb) {
382 leb[seb->lnum] = vmalloc(ubi->vtbl_size);
383 if (!leb[seb->lnum]) {
384 err = -ENOMEM;
385 goto out_free;
386 }
387 memset(leb[seb->lnum], 0, ubi->vtbl_size);
388
389 err = ubi_io_read_data(ubi, leb[seb->lnum], seb->pnum, 0,
390 ubi->vtbl_size);
391 if (err == UBI_IO_BITFLIPS || err == -EBADMSG)
392 /*
393 * Scrub the PEB later. Note, -EBADMSG indicates an
394 * uncorrectable ECC error, but we have our own CRC and
395 * the data will be checked later. If the data is OK,
396 * the PEB will be scrubbed (because we set
397 * seb->scrub). If the data is not OK, the contents of
398 * the PEB will be recovered from the second copy, and
399 * seb->scrub will be cleared in
400 * 'ubi_scan_add_used()'.
401 */
402 seb->scrub = 1;
403 else if (err)
404 goto out_free;
405 }
406
407 err = -EINVAL;
408 if (leb[0]) {
409 leb_corrupted[0] = vtbl_check(ubi, leb[0]);
410 if (leb_corrupted[0] < 0)
411 goto out_free;
412 }
413
414 if (!leb_corrupted[0]) {
415 /* LEB 0 is OK */
416 if (leb[1])
417 leb_corrupted[1] = memcmp(leb[0], leb[1], ubi->vtbl_size);
418 if (leb_corrupted[1]) {
419 ubi_warn("volume table copy #2 is corrupted");
420 err = create_vtbl(ubi, si, 1, leb[0]);
421 if (err)
422 goto out_free;
423 ubi_msg("volume table was restored");
424 }
425
426 /* Both LEB 1 and LEB 2 are OK and consistent */
427 vfree(leb[1]);
428 return leb[0];
429 } else {
430 /* LEB 0 is corrupted or does not exist */
431 if (leb[1]) {
432 leb_corrupted[1] = vtbl_check(ubi, leb[1]);
433 if (leb_corrupted[1] < 0)
434 goto out_free;
435 }
436 if (leb_corrupted[1]) {
437 /* Both LEB 0 and LEB 1 are corrupted */
438 ubi_err("both volume tables are corrupted");
439 goto out_free;
440 }
441
442 ubi_warn("volume table copy #1 is corrupted");
443 err = create_vtbl(ubi, si, 0, leb[1]);
444 if (err)
445 goto out_free;
446 ubi_msg("volume table was restored");
447
448 vfree(leb[0]);
449 return leb[1];
450 }
451
452out_free:
453 vfree(leb[0]);
454 vfree(leb[1]);
455 return ERR_PTR(err);
456}
457
458/**
459 * create_empty_lvol - create empty layout volume.
460 * @ubi: UBI device description object
461 * @si: scanning information
462 *
463 * This function returns volume table contents in case of success and a
464 * negative error code in case of failure.
465 */
466static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
467 struct ubi_scan_info *si)
468{
469 int i;
470 struct ubi_vtbl_record *vtbl;
471
472 vtbl = vmalloc(ubi->vtbl_size);
473 if (!vtbl)
474 return ERR_PTR(-ENOMEM);
475 memset(vtbl, 0, ubi->vtbl_size);
476
477 for (i = 0; i < ubi->vtbl_slots; i++)
478 memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);
479
480 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
481 int err;
482
483 err = create_vtbl(ubi, si, i, vtbl);
484 if (err) {
485 vfree(vtbl);
486 return ERR_PTR(err);
487 }
488 }
489
490 return vtbl;
491}
492
493/**
494 * init_volumes - initialize volume information for existing volumes.
495 * @ubi: UBI device description object
496 * @si: scanning information
497 * @vtbl: volume table
498 *
499 * This function allocates volume description objects for existing volumes.
500 * Returns zero in case of success and a negative error code in case of
501 * failure.
502 */
503static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si,
504 const struct ubi_vtbl_record *vtbl)
505{
506 int i, reserved_pebs = 0;
507 struct ubi_scan_volume *sv;
508 struct ubi_volume *vol;
509
510 for (i = 0; i < ubi->vtbl_slots; i++) {
511 cond_resched();
512
513 if (be32_to_cpu(vtbl[i].reserved_pebs) == 0)
514 continue; /* Empty record */
515
516 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
517 if (!vol)
518 return -ENOMEM;
519
520 vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
521 vol->alignment = be32_to_cpu(vtbl[i].alignment);
522 vol->data_pad = be32_to_cpu(vtbl[i].data_pad);
Peter Hortonceeba002010-06-12 10:11:56 +0900523 vol->upd_marker = vtbl[i].upd_marker;
Kyungmin Parkc91a7192008-11-19 16:28:06 +0100524 vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
525 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
526 vol->name_len = be16_to_cpu(vtbl[i].name_len);
527 vol->usable_leb_size = ubi->leb_size - vol->data_pad;
528 memcpy(vol->name, vtbl[i].name, vol->name_len);
529 vol->name[vol->name_len] = '\0';
530 vol->vol_id = i;
531
532 if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
533 /* Auto re-size flag may be set only for one volume */
534 if (ubi->autoresize_vol_id != -1) {
535 ubi_err("more then one auto-resize volume (%d "
536 "and %d)", ubi->autoresize_vol_id, i);
537 kfree(vol);
538 return -EINVAL;
539 }
540
541 ubi->autoresize_vol_id = i;
542 }
543
544 ubi_assert(!ubi->volumes[i]);
545 ubi->volumes[i] = vol;
546 ubi->vol_count += 1;
547 vol->ubi = ubi;
548 reserved_pebs += vol->reserved_pebs;
549
550 /*
551 * In case of dynamic volume UBI knows nothing about how many
552 * data is stored there. So assume the whole volume is used.
553 */
554 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
555 vol->used_ebs = vol->reserved_pebs;
556 vol->last_eb_bytes = vol->usable_leb_size;
557 vol->used_bytes =
558 (long long)vol->used_ebs * vol->usable_leb_size;
559 continue;
560 }
561
562 /* Static volumes only */
563 sv = ubi_scan_find_sv(si, i);
564 if (!sv) {
565 /*
566 * No eraseblocks belonging to this volume found. We
567 * don't actually know whether this static volume is
568 * completely corrupted or just contains no data. And
569 * we cannot know this as long as data size is not
570 * stored on flash. So we just assume the volume is
571 * empty. FIXME: this should be handled.
572 */
573 continue;
574 }
575
576 if (sv->leb_count != sv->used_ebs) {
577 /*
578 * We found a static volume which misses several
579 * eraseblocks. Treat it as corrupted.
580 */
581 ubi_warn("static volume %d misses %d LEBs - corrupted",
582 sv->vol_id, sv->used_ebs - sv->leb_count);
583 vol->corrupted = 1;
584 continue;
585 }
586
587 vol->used_ebs = sv->used_ebs;
588 vol->used_bytes =
589 (long long)(vol->used_ebs - 1) * vol->usable_leb_size;
590 vol->used_bytes += sv->last_data_size;
591 vol->last_eb_bytes = sv->last_data_size;
592 }
593
594 /* And add the layout volume */
595 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
596 if (!vol)
597 return -ENOMEM;
598
599 vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
600 vol->alignment = 1;
601 vol->vol_type = UBI_DYNAMIC_VOLUME;
602 vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
603 memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
604 vol->usable_leb_size = ubi->leb_size;
605 vol->used_ebs = vol->reserved_pebs;
606 vol->last_eb_bytes = vol->reserved_pebs;
607 vol->used_bytes =
608 (long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
609 vol->vol_id = UBI_LAYOUT_VOLUME_ID;
610 vol->ref_count = 1;
611
612 ubi_assert(!ubi->volumes[i]);
613 ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
614 reserved_pebs += vol->reserved_pebs;
615 ubi->vol_count += 1;
616 vol->ubi = ubi;
617
618 if (reserved_pebs > ubi->avail_pebs)
619 ubi_err("not enough PEBs, required %d, available %d",
620 reserved_pebs, ubi->avail_pebs);
621 ubi->rsvd_pebs += reserved_pebs;
622 ubi->avail_pebs -= reserved_pebs;
623
624 return 0;
625}
626
627/**
628 * check_sv - check volume scanning information.
629 * @vol: UBI volume description object
630 * @sv: volume scanning information
631 *
632 * This function returns zero if the volume scanning information is consistent
633 * to the data read from the volume tabla, and %-EINVAL if not.
634 */
635static int check_sv(const struct ubi_volume *vol,
636 const struct ubi_scan_volume *sv)
637{
638 int err;
639
640 if (sv->highest_lnum >= vol->reserved_pebs) {
641 err = 1;
642 goto bad;
643 }
644 if (sv->leb_count > vol->reserved_pebs) {
645 err = 2;
646 goto bad;
647 }
648 if (sv->vol_type != vol->vol_type) {
649 err = 3;
650 goto bad;
651 }
652 if (sv->used_ebs > vol->reserved_pebs) {
653 err = 4;
654 goto bad;
655 }
656 if (sv->data_pad != vol->data_pad) {
657 err = 5;
658 goto bad;
659 }
660 return 0;
661
662bad:
663 ubi_err("bad scanning information, error %d", err);
664 ubi_dbg_dump_sv(sv);
665 ubi_dbg_dump_vol_info(vol);
666 return -EINVAL;
667}
668
669/**
670 * check_scanning_info - check that scanning information.
671 * @ubi: UBI device description object
672 * @si: scanning information
673 *
674 * Even though we protect on-flash data by CRC checksums, we still don't trust
675 * the media. This function ensures that scanning information is consistent to
676 * the information read from the volume table. Returns zero if the scanning
677 * information is OK and %-EINVAL if it is not.
678 */
679static int check_scanning_info(const struct ubi_device *ubi,
680 struct ubi_scan_info *si)
681{
682 int err, i;
683 struct ubi_scan_volume *sv;
684 struct ubi_volume *vol;
685
686 if (si->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
687 ubi_err("scanning found %d volumes, maximum is %d + %d",
688 si->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
689 return -EINVAL;
690 }
691
692 if (si->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT &&
693 si->highest_vol_id < UBI_INTERNAL_VOL_START) {
694 ubi_err("too large volume ID %d found by scanning",
695 si->highest_vol_id);
696 return -EINVAL;
697 }
698
699 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
700 cond_resched();
701
702 sv = ubi_scan_find_sv(si, i);
703 vol = ubi->volumes[i];
704 if (!vol) {
705 if (sv)
706 ubi_scan_rm_volume(si, sv);
707 continue;
708 }
709
710 if (vol->reserved_pebs == 0) {
711 ubi_assert(i < ubi->vtbl_slots);
712
713 if (!sv)
714 continue;
715
716 /*
717 * During scanning we found a volume which does not
718 * exist according to the information in the volume
719 * table. This must have happened due to an unclean
720 * reboot while the volume was being removed. Discard
721 * these eraseblocks.
722 */
723 ubi_msg("finish volume %d removal", sv->vol_id);
724 ubi_scan_rm_volume(si, sv);
725 } else if (sv) {
726 err = check_sv(vol, sv);
727 if (err)
728 return err;
729 }
730 }
731
732 return 0;
733}
734
735/**
736 * ubi_read_volume_table - read volume table.
737 * information.
738 * @ubi: UBI device description object
739 * @si: scanning information
740 *
741 * This function reads volume table, checks it, recover from errors if needed,
742 * or creates it if needed. Returns zero in case of success and a negative
743 * error code in case of failure.
744 */
745int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si)
746{
747 int i, err;
748 struct ubi_scan_volume *sv;
749
750 empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
751
752 /*
753 * The number of supported volumes is limited by the eraseblock size
754 * and by the UBI_MAX_VOLUMES constant.
755 */
756 ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
757 if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
758 ubi->vtbl_slots = UBI_MAX_VOLUMES;
759
760 ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
761 ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);
762
763 sv = ubi_scan_find_sv(si, UBI_LAYOUT_VOLUME_ID);
764 if (!sv) {
765 /*
766 * No logical eraseblocks belonging to the layout volume were
767 * found. This could mean that the flash is just empty. In
768 * this case we create empty layout volume.
769 *
770 * But if flash is not empty this must be a corruption or the
771 * MTD device just contains garbage.
772 */
773 if (si->is_empty) {
774 ubi->vtbl = create_empty_lvol(ubi, si);
775 if (IS_ERR(ubi->vtbl))
776 return PTR_ERR(ubi->vtbl);
777 } else {
778 ubi_err("the layout volume was not found");
779 return -EINVAL;
780 }
781 } else {
782 if (sv->leb_count > UBI_LAYOUT_VOLUME_EBS) {
783 /* This must not happen with proper UBI images */
784 dbg_err("too many LEBs (%d) in layout volume",
785 sv->leb_count);
786 return -EINVAL;
787 }
788
789 ubi->vtbl = process_lvol(ubi, si, sv);
790 if (IS_ERR(ubi->vtbl))
791 return PTR_ERR(ubi->vtbl);
792 }
793
794 ubi->avail_pebs = ubi->good_peb_count;
795
796 /*
797 * The layout volume is OK, initialize the corresponding in-RAM data
798 * structures.
799 */
800 err = init_volumes(ubi, si, ubi->vtbl);
801 if (err)
802 goto out_free;
803
804 /*
805 * Get sure that the scanning information is consistent to the
806 * information stored in the volume table.
807 */
808 err = check_scanning_info(ubi, si);
809 if (err)
810 goto out_free;
811
812 return 0;
813
814out_free:
815 vfree(ubi->vtbl);
816 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++)
817 if (ubi->volumes[i]) {
818 kfree(ubi->volumes[i]);
819 ubi->volumes[i] = NULL;
820 }
821 return err;
822}
823
824#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
825
826/**
827 * paranoid_vtbl_check - check volume table.
828 * @ubi: UBI device description object
829 */
830static void paranoid_vtbl_check(const struct ubi_device *ubi)
831{
832 if (vtbl_check(ubi, ubi->vtbl)) {
833 ubi_err("paranoid check failed");
834 BUG();
835 }
836}
837
838#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */