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-rw-r--r--drivers/mtd/ubi/vtbl.c809
1 files changed, 809 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
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index 000000000000..b6fd6bbd941e
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1/*
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#include <linux/crc32.h>
60#include <linux/err.h>
61#include <asm/div64.h>
62#include "ubi.h"
63
64#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
65static void paranoid_vtbl_check(const struct ubi_device *ubi);
66#else
67#define paranoid_vtbl_check(ubi)
68#endif
69
70/* Empty volume table record */
71static struct ubi_vtbl_record empty_vtbl_record;
72
73/**
74 * ubi_change_vtbl_record - change volume table record.
75 * @ubi: UBI device description object
76 * @idx: table index to change
77 * @vtbl_rec: new volume table record
78 *
79 * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
80 * volume table record is written. The caller does not have to calculate CRC of
81 * the record as it is done by this function. Returns zero in case of success
82 * and a negative error code in case of failure.
83 */
84int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
85 struct ubi_vtbl_record *vtbl_rec)
86{
87 int i, err;
88 uint32_t crc;
89
90 ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
91
92 if (!vtbl_rec)
93 vtbl_rec = &empty_vtbl_record;
94 else {
95 crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC);
96 vtbl_rec->crc = cpu_to_ubi32(crc);
97 }
98
99 dbg_msg("change record %d", idx);
100 ubi_dbg_dump_vtbl_record(vtbl_rec, idx);
101
102 mutex_lock(&ubi->vtbl_mutex);
103 memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
104 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
105 err = ubi_eba_unmap_leb(ubi, UBI_LAYOUT_VOL_ID, i);
106 if (err) {
107 mutex_unlock(&ubi->vtbl_mutex);
108 return err;
109 }
110 err = ubi_eba_write_leb(ubi, UBI_LAYOUT_VOL_ID, i, ubi->vtbl, 0,
111 ubi->vtbl_size, UBI_LONGTERM);
112 if (err) {
113 mutex_unlock(&ubi->vtbl_mutex);
114 return err;
115 }
116 }
117
118 paranoid_vtbl_check(ubi);
119 mutex_unlock(&ubi->vtbl_mutex);
120 return ubi_wl_flush(ubi);
121}
122
123/**
124 * vol_til_check - check if volume table is not corrupted and contains sensible
125 * data.
126 *
127 * @ubi: UBI device description object
128 * @vtbl: volume table
129 *
130 * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
131 * and %-EINVAL if it contains inconsistent data.
132 */
133static int vtbl_check(const struct ubi_device *ubi,
134 const struct ubi_vtbl_record *vtbl)
135{
136 int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
137 int upd_marker;
138 uint32_t crc;
139 const char *name;
140
141 for (i = 0; i < ubi->vtbl_slots; i++) {
142 cond_resched();
143
144 reserved_pebs = ubi32_to_cpu(vtbl[i].reserved_pebs);
145 alignment = ubi32_to_cpu(vtbl[i].alignment);
146 data_pad = ubi32_to_cpu(vtbl[i].data_pad);
147 upd_marker = vtbl[i].upd_marker;
148 vol_type = vtbl[i].vol_type;
149 name_len = ubi16_to_cpu(vtbl[i].name_len);
150 name = &vtbl[i].name[0];
151
152 crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
153 if (ubi32_to_cpu(vtbl[i].crc) != crc) {
154 ubi_err("bad CRC at record %u: %#08x, not %#08x",
155 i, crc, ubi32_to_cpu(vtbl[i].crc));
156 ubi_dbg_dump_vtbl_record(&vtbl[i], i);
157 return 1;
158 }
159
160 if (reserved_pebs == 0) {
161 if (memcmp(&vtbl[i], &empty_vtbl_record,
162 UBI_VTBL_RECORD_SIZE)) {
163 dbg_err("bad empty record");
164 goto bad;
165 }
166 continue;
167 }
168
169 if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
170 name_len < 0) {
171 dbg_err("negative values");
172 goto bad;
173 }
174
175 if (alignment > ubi->leb_size || alignment == 0) {
176 dbg_err("bad alignment");
177 goto bad;
178 }
179
180 n = alignment % ubi->min_io_size;
181 if (alignment != 1 && n) {
182 dbg_err("alignment is not multiple of min I/O unit");
183 goto bad;
184 }
185
186 n = ubi->leb_size % alignment;
187 if (data_pad != n) {
188 dbg_err("bad data_pad, has to be %d", n);
189 goto bad;
190 }
191
192 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
193 dbg_err("bad vol_type");
194 goto bad;
195 }
196
197 if (upd_marker != 0 && upd_marker != 1) {
198 dbg_err("bad upd_marker");
199 goto bad;
200 }
201
202 if (reserved_pebs > ubi->good_peb_count) {
203 dbg_err("too large reserved_pebs, good PEBs %d",
204 ubi->good_peb_count);
205 goto bad;
206 }
207
208 if (name_len > UBI_VOL_NAME_MAX) {
209 dbg_err("too long volume name, max %d",
210 UBI_VOL_NAME_MAX);
211 goto bad;
212 }
213
214 if (name[0] == '\0') {
215 dbg_err("NULL volume name");
216 goto bad;
217 }
218
219 if (name_len != strnlen(name, name_len + 1)) {
220 dbg_err("bad name_len");
221 goto bad;
222 }
223 }
224
225 /* Checks that all names are unique */
226 for (i = 0; i < ubi->vtbl_slots - 1; i++) {
227 for (n = i + 1; n < ubi->vtbl_slots; n++) {
228 int len1 = ubi16_to_cpu(vtbl[i].name_len);
229 int len2 = ubi16_to_cpu(vtbl[n].name_len);
230
231 if (len1 > 0 && len1 == len2 &&
232 !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
233 ubi_err("volumes %d and %d have the same name"
234 " \"%s\"", i, n, vtbl[i].name);
235 ubi_dbg_dump_vtbl_record(&vtbl[i], i);
236 ubi_dbg_dump_vtbl_record(&vtbl[n], n);
237 return -EINVAL;
238 }
239 }
240 }
241
242 return 0;
243
244bad:
245 ubi_err("volume table check failed, record %d", i);
246 ubi_dbg_dump_vtbl_record(&vtbl[i], i);
247 return -EINVAL;
248}
249
250/**
251 * create_vtbl - create a copy of volume table.
252 * @ubi: UBI device description object
253 * @si: scanning information
254 * @copy: number of the volume table copy
255 * @vtbl: contents of the volume table
256 *
257 * This function returns zero in case of success and a negative error code in
258 * case of failure.
259 */
260static int create_vtbl(const struct ubi_device *ubi, struct ubi_scan_info *si,
261 int copy, void *vtbl)
262{
263 int err, tries = 0;
264 static struct ubi_vid_hdr *vid_hdr;
265 struct ubi_scan_volume *sv;
266 struct ubi_scan_leb *new_seb, *old_seb = NULL;
267
268 ubi_msg("create volume table (copy #%d)", copy + 1);
269
270 vid_hdr = ubi_zalloc_vid_hdr(ubi);
271 if (!vid_hdr)
272 return -ENOMEM;
273
274 /*
275 * Check if there is a logical eraseblock which would have to contain
276 * this volume table copy was found during scanning. It has to be wiped
277 * out.
278 */
279 sv = ubi_scan_find_sv(si, UBI_LAYOUT_VOL_ID);
280 if (sv)
281 old_seb = ubi_scan_find_seb(sv, copy);
282
283retry:
284 new_seb = ubi_scan_get_free_peb(ubi, si);
285 if (IS_ERR(new_seb)) {
286 err = PTR_ERR(new_seb);
287 goto out_free;
288 }
289
290 vid_hdr->vol_type = UBI_VID_DYNAMIC;
291 vid_hdr->vol_id = cpu_to_ubi32(UBI_LAYOUT_VOL_ID);
292 vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT;
293 vid_hdr->data_size = vid_hdr->used_ebs =
294 vid_hdr->data_pad = cpu_to_ubi32(0);
295 vid_hdr->lnum = cpu_to_ubi32(copy);
296 vid_hdr->sqnum = cpu_to_ubi64(++si->max_sqnum);
297 vid_hdr->leb_ver = cpu_to_ubi32(old_seb ? old_seb->leb_ver + 1: 0);
298
299 /* The EC header is already there, write the VID header */
300 err = ubi_io_write_vid_hdr(ubi, new_seb->pnum, vid_hdr);
301 if (err)
302 goto write_error;
303
304 /* Write the layout volume contents */
305 err = ubi_io_write_data(ubi, vtbl, new_seb->pnum, 0, ubi->vtbl_size);
306 if (err)
307 goto write_error;
308
309 /*
310 * And add it to the scanning information. Don't delete the old
311 * @old_seb as it will be deleted and freed in 'ubi_scan_add_used()'.
312 */
313 err = ubi_scan_add_used(ubi, si, new_seb->pnum, new_seb->ec,
314 vid_hdr, 0);
315 kfree(new_seb);
316 ubi_free_vid_hdr(ubi, vid_hdr);
317 return err;
318
319write_error:
320 kfree(new_seb);
321 /* May be this physical eraseblock went bad, try to pick another one */
322 if (++tries <= 5) {
323 err = ubi_scan_add_to_list(si, new_seb->pnum, new_seb->ec,
324 &si->corr);
325 if (!err)
326 goto retry;
327 }
328out_free:
329 ubi_free_vid_hdr(ubi, vid_hdr);
330 return err;
331
332}
333
334/**
335 * process_lvol - process the layout volume.
336 * @ubi: UBI device description object
337 * @si: scanning information
338 * @sv: layout volume scanning information
339 *
340 * This function is responsible for reading the layout volume, ensuring it is
341 * not corrupted, and recovering from corruptions if needed. Returns volume
342 * table in case of success and a negative error code in case of failure.
343 */
344static struct ubi_vtbl_record *process_lvol(const struct ubi_device *ubi,
345 struct ubi_scan_info *si,
346 struct ubi_scan_volume *sv)
347{
348 int err;
349 struct rb_node *rb;
350 struct ubi_scan_leb *seb;
351 struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL };
352 int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1};
353
354 /*
355 * UBI goes through the following steps when it changes the layout
356 * volume:
357 * a. erase LEB 0;
358 * b. write new data to LEB 0;
359 * c. erase LEB 1;
360 * d. write new data to LEB 1.
361 *
362 * Before the change, both LEBs contain the same data.
363 *
364 * Due to unclean reboots, the contents of LEB 0 may be lost, but there
365 * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not.
366 * Similarly, LEB 1 may be lost, but there should be LEB 0. And
367 * finally, unclean reboots may result in a situation when neither LEB
368 * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB
369 * 0 contains more recent information.
370 *
371 * So the plan is to first check LEB 0. Then
372 * a. if LEB 0 is OK, it must be containing the most resent data; then
373 * we compare it with LEB 1, and if they are different, we copy LEB
374 * 0 to LEB 1;
375 * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1
376 * to LEB 0.
377 */
378
379 dbg_msg("check layout volume");
380
381 /* Read both LEB 0 and LEB 1 into memory */
382 ubi_rb_for_each_entry(rb, seb, &sv->root, u.rb) {
383 leb[seb->lnum] = kzalloc(ubi->vtbl_size, GFP_KERNEL);
384 if (!leb[seb->lnum]) {
385 err = -ENOMEM;
386 goto out_free;
387 }
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 /* Scrub the PEB later */
393 seb->scrub = 1;
394 else if (err)
395 goto out_free;
396 }
397
398 err = -EINVAL;
399 if (leb[0]) {
400 leb_corrupted[0] = vtbl_check(ubi, leb[0]);
401 if (leb_corrupted[0] < 0)
402 goto out_free;
403 }
404
405 if (!leb_corrupted[0]) {
406 /* LEB 0 is OK */
407 if (leb[1])
408 leb_corrupted[1] = memcmp(leb[0], leb[1], ubi->vtbl_size);
409 if (leb_corrupted[1]) {
410 ubi_warn("volume table copy #2 is corrupted");
411 err = create_vtbl(ubi, si, 1, leb[0]);
412 if (err)
413 goto out_free;
414 ubi_msg("volume table was restored");
415 }
416
417 /* Both LEB 1 and LEB 2 are OK and consistent */
418 kfree(leb[1]);
419 return leb[0];
420 } else {
421 /* LEB 0 is corrupted or does not exist */
422 if (leb[1]) {
423 leb_corrupted[1] = vtbl_check(ubi, leb[1]);
424 if (leb_corrupted[1] < 0)
425 goto out_free;
426 }
427 if (leb_corrupted[1]) {
428 /* Both LEB 0 and LEB 1 are corrupted */
429 ubi_err("both volume tables are corrupted");
430 goto out_free;
431 }
432
433 ubi_warn("volume table copy #1 is corrupted");
434 err = create_vtbl(ubi, si, 0, leb[1]);
435 if (err)
436 goto out_free;
437 ubi_msg("volume table was restored");
438
439 kfree(leb[0]);
440 return leb[1];
441 }
442
443out_free:
444 kfree(leb[0]);
445 kfree(leb[1]);
446 return ERR_PTR(err);
447}
448
449/**
450 * create_empty_lvol - create empty layout volume.
451 * @ubi: UBI device description object
452 * @si: scanning information
453 *
454 * This function returns volume table contents in case of success and a
455 * negative error code in case of failure.
456 */
457static struct ubi_vtbl_record *create_empty_lvol(const struct ubi_device *ubi,
458 struct ubi_scan_info *si)
459{
460 int i;
461 struct ubi_vtbl_record *vtbl;
462
463 vtbl = kzalloc(ubi->vtbl_size, GFP_KERNEL);
464 if (!vtbl)
465 return ERR_PTR(-ENOMEM);
466
467 for (i = 0; i < ubi->vtbl_slots; i++)
468 memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);
469
470 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
471 int err;
472
473 err = create_vtbl(ubi, si, i, vtbl);
474 if (err) {
475 kfree(vtbl);
476 return ERR_PTR(err);
477 }
478 }
479
480 return vtbl;
481}
482
483/**
484 * init_volumes - initialize volume information for existing volumes.
485 * @ubi: UBI device description object
486 * @si: scanning information
487 * @vtbl: volume table
488 *
489 * This function allocates volume description objects for existing volumes.
490 * Returns zero in case of success and a negative error code in case of
491 * failure.
492 */
493static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si,
494 const struct ubi_vtbl_record *vtbl)
495{
496 int i, reserved_pebs = 0;
497 struct ubi_scan_volume *sv;
498 struct ubi_volume *vol;
499
500 for (i = 0; i < ubi->vtbl_slots; i++) {
501 cond_resched();
502
503 if (ubi32_to_cpu(vtbl[i].reserved_pebs) == 0)
504 continue; /* Empty record */
505
506 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
507 if (!vol)
508 return -ENOMEM;
509
510 vol->reserved_pebs = ubi32_to_cpu(vtbl[i].reserved_pebs);
511 vol->alignment = ubi32_to_cpu(vtbl[i].alignment);
512 vol->data_pad = ubi32_to_cpu(vtbl[i].data_pad);
513 vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
514 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
515 vol->name_len = ubi16_to_cpu(vtbl[i].name_len);
516 vol->usable_leb_size = ubi->leb_size - vol->data_pad;
517 memcpy(vol->name, vtbl[i].name, vol->name_len);
518 vol->name[vol->name_len] = '\0';
519 vol->vol_id = i;
520
521 ubi_assert(!ubi->volumes[i]);
522 ubi->volumes[i] = vol;
523 ubi->vol_count += 1;
524 vol->ubi = ubi;
525 reserved_pebs += vol->reserved_pebs;
526
527 /*
528 * In case of dynamic volume UBI knows nothing about how many
529 * data is stored there. So assume the whole volume is used.
530 */
531 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
532 vol->used_ebs = vol->reserved_pebs;
533 vol->last_eb_bytes = vol->usable_leb_size;
534 vol->used_bytes = vol->used_ebs * vol->usable_leb_size;
535 continue;
536 }
537
538 /* Static volumes only */
539 sv = ubi_scan_find_sv(si, i);
540 if (!sv) {
541 /*
542 * No eraseblocks belonging to this volume found. We
543 * don't actually know whether this static volume is
544 * completely corrupted or just contains no data. And
545 * we cannot know this as long as data size is not
546 * stored on flash. So we just assume the volume is
547 * empty. FIXME: this should be handled.
548 */
549 continue;
550 }
551
552 if (sv->leb_count != sv->used_ebs) {
553 /*
554 * We found a static volume which misses several
555 * eraseblocks. Treat it as corrupted.
556 */
557 ubi_warn("static volume %d misses %d LEBs - corrupted",
558 sv->vol_id, sv->used_ebs - sv->leb_count);
559 vol->corrupted = 1;
560 continue;
561 }
562
563 vol->used_ebs = sv->used_ebs;
564 vol->used_bytes = (vol->used_ebs - 1) * vol->usable_leb_size;
565 vol->used_bytes += sv->last_data_size;
566 vol->last_eb_bytes = sv->last_data_size;
567 }
568
569 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
570 if (!vol)
571 return -ENOMEM;
572
573 vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
574 vol->alignment = 1;
575 vol->vol_type = UBI_DYNAMIC_VOLUME;
576 vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
577 memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
578 vol->usable_leb_size = ubi->leb_size;
579 vol->used_ebs = vol->reserved_pebs;
580 vol->last_eb_bytes = vol->reserved_pebs;
581 vol->used_bytes = vol->used_ebs * (ubi->leb_size - vol->data_pad);
582 vol->vol_id = UBI_LAYOUT_VOL_ID;
583
584 ubi_assert(!ubi->volumes[i]);
585 ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
586 reserved_pebs += vol->reserved_pebs;
587 ubi->vol_count += 1;
588 vol->ubi = ubi;
589
590 if (reserved_pebs > ubi->avail_pebs)
591 ubi_err("not enough PEBs, required %d, available %d",
592 reserved_pebs, ubi->avail_pebs);
593 ubi->rsvd_pebs += reserved_pebs;
594 ubi->avail_pebs -= reserved_pebs;
595
596 return 0;
597}
598
599/**
600 * check_sv - check volume scanning information.
601 * @vol: UBI volume description object
602 * @sv: volume scanning information
603 *
604 * This function returns zero if the volume scanning information is consistent
605 * to the data read from the volume tabla, and %-EINVAL if not.
606 */
607static int check_sv(const struct ubi_volume *vol,
608 const struct ubi_scan_volume *sv)
609{
610 if (sv->highest_lnum >= vol->reserved_pebs) {
611 dbg_err("bad highest_lnum");
612 goto bad;
613 }
614 if (sv->leb_count > vol->reserved_pebs) {
615 dbg_err("bad leb_count");
616 goto bad;
617 }
618 if (sv->vol_type != vol->vol_type) {
619 dbg_err("bad vol_type");
620 goto bad;
621 }
622 if (sv->used_ebs > vol->reserved_pebs) {
623 dbg_err("bad used_ebs");
624 goto bad;
625 }
626 if (sv->data_pad != vol->data_pad) {
627 dbg_err("bad data_pad");
628 goto bad;
629 }
630 return 0;
631
632bad:
633 ubi_err("bad scanning information");
634 ubi_dbg_dump_sv(sv);
635 ubi_dbg_dump_vol_info(vol);
636 return -EINVAL;
637}
638
639/**
640 * check_scanning_info - check that scanning information.
641 * @ubi: UBI device description object
642 * @si: scanning information
643 *
644 * Even though we protect on-flash data by CRC checksums, we still don't trust
645 * the media. This function ensures that scanning information is consistent to
646 * the information read from the volume table. Returns zero if the scanning
647 * information is OK and %-EINVAL if it is not.
648 */
649static int check_scanning_info(const struct ubi_device *ubi,
650 struct ubi_scan_info *si)
651{
652 int err, i;
653 struct ubi_scan_volume *sv;
654 struct ubi_volume *vol;
655
656 if (si->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
657 ubi_err("scanning found %d volumes, maximum is %d + %d",
658 si->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
659 return -EINVAL;
660 }
661
662 if (si->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT&&
663 si->highest_vol_id < UBI_INTERNAL_VOL_START) {
664 ubi_err("too large volume ID %d found by scanning",
665 si->highest_vol_id);
666 return -EINVAL;
667 }
668
669
670 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
671 cond_resched();
672
673 sv = ubi_scan_find_sv(si, i);
674 vol = ubi->volumes[i];
675 if (!vol) {
676 if (sv)
677 ubi_scan_rm_volume(si, sv);
678 continue;
679 }
680
681 if (vol->reserved_pebs == 0) {
682 ubi_assert(i < ubi->vtbl_slots);
683
684 if (!sv)
685 continue;
686
687 /*
688 * During scanning we found a volume which does not
689 * exist according to the information in the volume
690 * table. This must have happened due to an unclean
691 * reboot while the volume was being removed. Discard
692 * these eraseblocks.
693 */
694 ubi_msg("finish volume %d removal", sv->vol_id);
695 ubi_scan_rm_volume(si, sv);
696 } else if (sv) {
697 err = check_sv(vol, sv);
698 if (err)
699 return err;
700 }
701 }
702
703 return 0;
704}
705
706/**
707 * ubi_read_volume_table - read volume table.
708 * information.
709 * @ubi: UBI device description object
710 * @si: scanning information
711 *
712 * This function reads volume table, checks it, recover from errors if needed,
713 * or creates it if needed. Returns zero in case of success and a negative
714 * error code in case of failure.
715 */
716int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si)
717{
718 int i, err;
719 struct ubi_scan_volume *sv;
720
721 empty_vtbl_record.crc = cpu_to_ubi32(0xf116c36b);
722
723 /*
724 * The number of supported volumes is limited by the eraseblock size
725 * and by the UBI_MAX_VOLUMES constant.
726 */
727 ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
728 if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
729 ubi->vtbl_slots = UBI_MAX_VOLUMES;
730
731 ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
732 ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);
733
734 sv = ubi_scan_find_sv(si, UBI_LAYOUT_VOL_ID);
735 if (!sv) {
736 /*
737 * No logical eraseblocks belonging to the layout volume were
738 * found. This could mean that the flash is just empty. In
739 * this case we create empty layout volume.
740 *
741 * But if flash is not empty this must be a corruption or the
742 * MTD device just contains garbage.
743 */
744 if (si->is_empty) {
745 ubi->vtbl = create_empty_lvol(ubi, si);
746 if (IS_ERR(ubi->vtbl))
747 return PTR_ERR(ubi->vtbl);
748 } else {
749 ubi_err("the layout volume was not found");
750 return -EINVAL;
751 }
752 } else {
753 if (sv->leb_count > UBI_LAYOUT_VOLUME_EBS) {
754 /* This must not happen with proper UBI images */
755 dbg_err("too many LEBs (%d) in layout volume",
756 sv->leb_count);
757 return -EINVAL;
758 }
759
760 ubi->vtbl = process_lvol(ubi, si, sv);
761 if (IS_ERR(ubi->vtbl))
762 return PTR_ERR(ubi->vtbl);
763 }
764
765 ubi->avail_pebs = ubi->good_peb_count;
766
767 /*
768 * The layout volume is OK, initialize the corresponding in-RAM data
769 * structures.
770 */
771 err = init_volumes(ubi, si, ubi->vtbl);
772 if (err)
773 goto out_free;
774
775 /*
776 * Get sure that the scanning information is consistent to the
777 * information stored in the volume table.
778 */
779 err = check_scanning_info(ubi, si);
780 if (err)
781 goto out_free;
782
783 return 0;
784
785out_free:
786 kfree(ubi->vtbl);
787 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++)
788 if (ubi->volumes[i]) {
789 kfree(ubi->volumes[i]);
790 ubi->volumes[i] = NULL;
791 }
792 return err;
793}
794
795#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
796
797/**
798 * paranoid_vtbl_check - check volume table.
799 * @ubi: UBI device description object
800 */
801static void paranoid_vtbl_check(const struct ubi_device *ubi)
802{
803 if (vtbl_check(ubi, ubi->vtbl)) {
804 ubi_err("paranoid check failed");
805 BUG();
806 }
807}
808
809#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */