1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2006
4 * Copyright (c) Nokia Corporation, 2006, 2007
5 *
6 * Author: Artem Bityutskiy (Битюцкий Артём)
7 */
8
9 /*
10 * This file includes volume table manipulation code. The volume table is an
11 * on-flash table containing volume meta-data like name, number of reserved
12 * physical eraseblocks, type, etc. The volume table is stored in the so-called
13 * "layout volume".
14 *
15 * The layout volume is an internal volume which is organized as follows. It
16 * consists of two logical eraseblocks - LEB 0 and LEB 1. Each logical
17 * eraseblock stores one volume table copy, i.e. LEB 0 and LEB 1 duplicate each
18 * other. This redundancy guarantees robustness to unclean reboots. The volume
19 * table is basically an array of volume table records. Each record contains
20 * full information about the volume and protected by a CRC checksum. Note,
21 * nowadays we use the atomic LEB change operation when updating the volume
22 * table, so we do not really need 2 LEBs anymore, but we preserve the older
23 * design for the backward compatibility reasons.
24 *
25 * When the volume table is changed, it is first changed in RAM. Then LEB 0 is
26 * erased, and the updated volume table is written back to LEB 0. Then same for
27 * LEB 1. This scheme guarantees recoverability from unclean reboots.
28 *
29 * In this UBI implementation the on-flash volume table does not contain any
30 * information about how much data static volumes contain.
31 *
32 * But it would still be beneficial to store this information in the volume
33 * table. For example, suppose we have a static volume X, and all its physical
34 * eraseblocks became bad for some reasons. Suppose we are attaching the
35 * corresponding MTD device, for some reason we find no logical eraseblocks
36 * corresponding to the volume X. According to the volume table volume X does
37 * exist. So we don't know whether it is just empty or all its physical
38 * eraseblocks went bad. So we cannot alarm the user properly.
39 *
40 * The volume table also stores so-called "update marker", which is used for
41 * volume updates. Before updating the volume, the update marker is set, and
42 * after the update operation is finished, the update marker is cleared. So if
43 * the update operation was interrupted (e.g. by an unclean reboot) - the
44 * update marker is still there and we know that the volume's contents is
45 * damaged.
46 */
47
48 #include <linux/crc32.h>
49 #include <linux/err.h>
50 #include <linux/slab.h>
51 #include <asm/div64.h>
52 #include "ubi.h"
53
54 static void self_vtbl_check(const struct ubi_device *ubi);
55
56 /* Empty volume table record */
57 static struct ubi_vtbl_record empty_vtbl_record;
58
59 /**
60 * ubi_update_layout_vol - helper for updatting layout volumes on flash
61 * @ubi: UBI device description object
62 */
63 static int ubi_update_layout_vol(struct ubi_device *ubi)
64 {
65 struct ubi_volume *layout_vol;
66 int i, err;
67
68 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
69 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
70 err = ubi_eba_atomic_leb_change(ubi, layout_vol, i, ubi->vtbl,
71 ubi->vtbl_size);
72 if (err)
73 return err;
74 }
75
76 return 0;
77 }
78
79 /**
80 * ubi_change_vtbl_record - change volume table record.
81 * @ubi: UBI device description object
82 * @idx: table index to change
83 * @vtbl_rec: new volume table record
84 *
85 * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
86 * volume table record is written. The caller does not have to calculate CRC of
87 * the record as it is done by this function. Returns zero in case of success
88 * and a negative error code in case of failure.
89 */
90 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
91 struct ubi_vtbl_record *vtbl_rec)
92 {
93 int err;
94 uint32_t crc;
95
96 ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
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 err = ubi_update_layout_vol(ubi);
107
108 self_vtbl_check(ubi);
109 return err ? err : 0;
110 }
111
112 /**
113 * ubi_vtbl_rename_volumes - rename UBI volumes in the volume table.
114 * @ubi: UBI device description object
115 * @rename_list: list of &struct ubi_rename_entry objects
116 *
117 * This function re-names multiple volumes specified in @req in the volume
118 * table. Returns zero in case of success and a negative error code in case of
119 * failure.
120 */
121 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
122 struct list_head *rename_list)
123 {
124 struct ubi_rename_entry *re;
125
126 list_for_each_entry(re, rename_list, list) {
127 uint32_t crc;
128 struct ubi_volume *vol = re->desc->vol;
129 struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol->vol_id];
130
131 if (re->remove) {
132 memcpy(vtbl_rec, &empty_vtbl_record,
133 sizeof(struct ubi_vtbl_record));
134 continue;
135 }
136
137 vtbl_rec->name_len = cpu_to_be16(re->new_name_len);
138 memcpy(vtbl_rec->name, re->new_name, re->new_name_len);
139 memset(vtbl_rec->name + re->new_name_len, 0,
140 UBI_VOL_NAME_MAX + 1 - re->new_name_len);
141 crc = crc32(UBI_CRC32_INIT, vtbl_rec,
142 UBI_VTBL_RECORD_SIZE_CRC);
143 vtbl_rec->crc = cpu_to_be32(crc);
144 }
145
146 return ubi_update_layout_vol(ubi);
147 }
148
149 /**
150 * vtbl_check - check if volume table is not corrupted and sensible.
151 * @ubi: UBI device description object
152 * @vtbl: volume table
153 *
154 * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
155 * and %-EINVAL if it contains inconsistent data.
156 */
157 static int vtbl_check(const struct ubi_device *ubi,
158 const struct ubi_vtbl_record *vtbl)
159 {
160 int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
161 int upd_marker, err;
162 uint32_t crc;
163 const char *name;
164
165 for (i = 0; i < ubi->vtbl_slots; i++) {
166 cond_resched();
167
168 reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
169 alignment = be32_to_cpu(vtbl[i].alignment);
170 data_pad = be32_to_cpu(vtbl[i].data_pad);
171 upd_marker = vtbl[i].upd_marker;
172 vol_type = vtbl[i].vol_type;
173 name_len = be16_to_cpu(vtbl[i].name_len);
174 name = &vtbl[i].name[0];
175
176 crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
177 if (be32_to_cpu(vtbl[i].crc) != crc) {
178 ubi_err(ubi, "bad CRC at record %u: %#08x, not %#08x",
179 i, crc, be32_to_cpu(vtbl[i].crc));
180 ubi_dump_vtbl_record(&vtbl[i], i);
181 return 1;
182 }
183
184 if (reserved_pebs == 0) {
185 if (memcmp(&vtbl[i], &empty_vtbl_record,
186 UBI_VTBL_RECORD_SIZE)) {
187 err = 2;
188 goto bad;
189 }
190 continue;
191 }
192
193 if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
194 name_len < 0) {
195 err = 3;
196 goto bad;
197 }
198
199 if (alignment > ubi->leb_size || alignment == 0) {
200 err = 4;
201 goto bad;
202 }
203
204 n = alignment & (ubi->min_io_size - 1);
205 if (alignment != 1 && n) {
206 err = 5;
207 goto bad;
208 }
209
210 n = ubi->leb_size % alignment;
211 if (data_pad != n) {
212 ubi_err(ubi, "bad data_pad, has to be %d", n);
213 err = 6;
214 goto bad;
215 }
216
217 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
218 err = 7;
219 goto bad;
220 }
221
222 if (upd_marker != 0 && upd_marker != 1) {
223 err = 8;
224 goto bad;
225 }
226
227 if (reserved_pebs > ubi->good_peb_count) {
228 ubi_err(ubi, "too large reserved_pebs %d, good PEBs %d",
229 reserved_pebs, ubi->good_peb_count);
230 err = 9;
231 goto bad;
232 }
233
234 if (name_len > UBI_VOL_NAME_MAX) {
235 err = 10;
236 goto bad;
237 }
238
239 if (name[0] == '\0') {
240 err = 11;
241 goto bad;
242 }
243
244 if (name_len != strnlen(name, name_len + 1)) {
245 err = 12;
246 goto bad;
247 }
248 }
249
250 /* Checks that all names are unique */
251 for (i = 0; i < ubi->vtbl_slots - 1; i++) {
252 for (n = i + 1; n < ubi->vtbl_slots; n++) {
253 int len1 = be16_to_cpu(vtbl[i].name_len);
254 int len2 = be16_to_cpu(vtbl[n].name_len);
255
256 if (len1 > 0 && len1 == len2 &&
257 !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
258 ubi_err(ubi, "volumes %d and %d have the same name \"%s\"",
259 i, n, vtbl[i].name);
260 ubi_dump_vtbl_record(&vtbl[i], i);
261 ubi_dump_vtbl_record(&vtbl[n], n);
262 return -EINVAL;
263 }
264 }
265 }
266
267 return 0;
268
269 bad:
270 ubi_err(ubi, "volume table check failed: record %d, error %d", i, err);
271 ubi_dump_vtbl_record(&vtbl[i], i);
272 return -EINVAL;
273 }
274
275 /**
276 * create_vtbl - create a copy of volume table.
277 * @ubi: UBI device description object
278 * @ai: attaching information
279 * @copy: number of the volume table copy
280 * @vtbl: contents of the volume table
281 *
282 * This function returns zero in case of success and a negative error code in
283 * case of failure.
284 */
285 static int create_vtbl(struct ubi_device *ubi, struct ubi_attach_info *ai,
286 int copy, void *vtbl)
287 {
288 int err, tries = 0;
289 struct ubi_vid_io_buf *vidb;
290 struct ubi_vid_hdr *vid_hdr;
291 struct ubi_ainf_peb *new_aeb;
292
293 dbg_gen("create volume table (copy #%d)", copy + 1);
294
295 vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
296 if (!vidb)
297 return -ENOMEM;
298
299 vid_hdr = ubi_get_vid_hdr(vidb);
300
301 retry:
302 new_aeb = ubi_early_get_peb(ubi, ai);
303 if (IS_ERR(new_aeb)) {
304 err = PTR_ERR(new_aeb);
305 goto out_free;
306 }
307
308 vid_hdr->vol_type = UBI_LAYOUT_VOLUME_TYPE;
309 vid_hdr->vol_id = cpu_to_be32(UBI_LAYOUT_VOLUME_ID);
310 vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT;
311 vid_hdr->data_size = vid_hdr->used_ebs =
312 vid_hdr->data_pad = cpu_to_be32(0);
313 vid_hdr->lnum = cpu_to_be32(copy);
314 vid_hdr->sqnum = cpu_to_be64(++ai->max_sqnum);
315
316 /* The EC header is already there, write the VID header */
317 err = ubi_io_write_vid_hdr(ubi, new_aeb->pnum, vidb);
318 if (err)
319 goto write_error;
320
321 /* Write the layout volume contents */
322 err = ubi_io_write_data(ubi, vtbl, new_aeb->pnum, 0, ubi->vtbl_size);
323 if (err)
324 goto write_error;
325
326 /*
327 * And add it to the attaching information. Don't delete the old version
328 * of this LEB as it will be deleted and freed in 'ubi_add_to_av()'.
329 */
330 err = ubi_add_to_av(ubi, ai, new_aeb->pnum, new_aeb->ec, vid_hdr, 0);
331 ubi_free_aeb(ai, new_aeb);
332 ubi_free_vid_buf(vidb);
333 return err;
334
335 write_error:
336 if (err == -EIO && ++tries <= 5) {
337 /*
338 * Probably this physical eraseblock went bad, try to pick
339 * another one.
340 */
341 list_add(&new_aeb->u.list, &ai->erase);
342 goto retry;
343 }
344 ubi_free_aeb(ai, new_aeb);
345 out_free:
346 ubi_free_vid_buf(vidb);
347 return err;
348
349 }
350
351 /**
352 * process_lvol - process the layout volume.
353 * @ubi: UBI device description object
354 * @ai: attaching information
355 * @av: layout volume attaching information
356 *
357 * This function is responsible for reading the layout volume, ensuring it is
358 * not corrupted, and recovering from corruptions if needed. Returns volume
359 * table in case of success and a negative error code in case of failure.
360 */
361 static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
362 struct ubi_attach_info *ai,
363 struct ubi_ainf_volume *av)
364 {
365 int err;
366 struct rb_node *rb;
367 struct ubi_ainf_peb *aeb;
368 struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL };
369 int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1};
370
371 /*
372 * UBI goes through the following steps when it changes the layout
373 * volume:
374 * a. erase LEB 0;
375 * b. write new data to LEB 0;
376 * c. erase LEB 1;
377 * d. write new data to LEB 1.
378 *
379 * Before the change, both LEBs contain the same data.
380 *
381 * Due to unclean reboots, the contents of LEB 0 may be lost, but there
382 * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not.
383 * Similarly, LEB 1 may be lost, but there should be LEB 0. And
384 * finally, unclean reboots may result in a situation when neither LEB
385 * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB
386 * 0 contains more recent information.
387 *
388 * So the plan is to first check LEB 0. Then
389 * a. if LEB 0 is OK, it must be containing the most recent data; then
390 * we compare it with LEB 1, and if they are different, we copy LEB
391 * 0 to LEB 1;
392 * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1
393 * to LEB 0.
394 */
395
396 dbg_gen("check layout volume");
397
398 /* Read both LEB 0 and LEB 1 into memory */
399 ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
400 leb[aeb->lnum] = vzalloc(ubi->vtbl_size);
401 if (!leb[aeb->lnum]) {
402 err = -ENOMEM;
403 goto out_free;
404 }
405
406 err = ubi_io_read_data(ubi, leb[aeb->lnum], aeb->pnum, 0,
407 ubi->vtbl_size);
408 if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err))
409 /*
410 * Scrub the PEB later. Note, -EBADMSG indicates an
411 * uncorrectable ECC error, but we have our own CRC and
412 * the data will be checked later. If the data is OK,
413 * the PEB will be scrubbed (because we set
414 * aeb->scrub). If the data is not OK, the contents of
415 * the PEB will be recovered from the second copy, and
416 * aeb->scrub will be cleared in
417 * 'ubi_add_to_av()'.
418 */
419 aeb->scrub = 1;
420 else if (err)
421 goto out_free;
422 }
423
424 err = -EINVAL;
425 if (leb[0]) {
426 leb_corrupted[0] = vtbl_check(ubi, leb[0]);
427 if (leb_corrupted[0] < 0)
428 goto out_free;
429 }
430
431 if (!leb_corrupted[0]) {
432 /* LEB 0 is OK */
433 if (leb[1])
434 leb_corrupted[1] = memcmp(leb[0], leb[1],
435 ubi->vtbl_size);
436 if (leb_corrupted[1]) {
437 ubi_warn(ubi, "volume table copy #2 is corrupted");
438 err = create_vtbl(ubi, ai, 1, leb[0]);
439 if (err)
440 goto out_free;
441 ubi_msg(ubi, "volume table was restored");
442 }
443
444 /* Both LEB 1 and LEB 2 are OK and consistent */
445 vfree(leb[1]);
446 return leb[0];
447 } else {
448 /* LEB 0 is corrupted or does not exist */
449 if (leb[1]) {
450 leb_corrupted[1] = vtbl_check(ubi, leb[1]);
451 if (leb_corrupted[1] < 0)
452 goto out_free;
453 }
454 if (leb_corrupted[1]) {
455 /* Both LEB 0 and LEB 1 are corrupted */
456 ubi_err(ubi, "both volume tables are corrupted");
457 goto out_free;
458 }
459
460 ubi_warn(ubi, "volume table copy #1 is corrupted");
461 err = create_vtbl(ubi, ai, 0, leb[1]);
462 if (err)
463 goto out_free;
464 ubi_msg(ubi, "volume table was restored");
465
466 vfree(leb[0]);
467 return leb[1];
468 }
469
470 out_free:
471 vfree(leb[0]);
472 vfree(leb[1]);
473 return ERR_PTR(err);
474 }
475
476 /**
477 * create_empty_lvol - create empty layout volume.
478 * @ubi: UBI device description object
479 * @ai: attaching information
480 *
481 * This function returns volume table contents in case of success and a
482 * negative error code in case of failure.
483 */
484 static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
485 struct ubi_attach_info *ai)
486 {
487 int i;
488 struct ubi_vtbl_record *vtbl;
489
490 vtbl = vzalloc(ubi->vtbl_size);
491 if (!vtbl)
492 return ERR_PTR(-ENOMEM);
493
494 for (i = 0; i < ubi->vtbl_slots; i++)
495 memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);
496
497 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
498 int err;
499
500 err = create_vtbl(ubi, ai, i, vtbl);
501 if (err) {
502 vfree(vtbl);
503 return ERR_PTR(err);
504 }
505 }
506
507 return vtbl;
508 }
509
510 /**
511 * init_volumes - initialize volume information for existing volumes.
512 * @ubi: UBI device description object
513 * @ai: scanning information
514 * @vtbl: volume table
515 *
516 * This function allocates volume description objects for existing volumes.
517 * Returns zero in case of success and a negative error code in case of
518 * failure.
519 */
520 static int init_volumes(struct ubi_device *ubi,
521 const struct ubi_attach_info *ai,
522 const struct ubi_vtbl_record *vtbl)
523 {
524 int i, err, reserved_pebs = 0;
525 struct ubi_ainf_volume *av;
526 struct ubi_volume *vol;
527
528 for (i = 0; i < ubi->vtbl_slots; i++) {
529 cond_resched();
530
531 if (be32_to_cpu(vtbl[i].reserved_pebs) == 0)
532 continue; /* Empty record */
533
534 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
535 if (!vol)
536 return -ENOMEM;
537
538 vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
539 vol->alignment = be32_to_cpu(vtbl[i].alignment);
540 vol->data_pad = be32_to_cpu(vtbl[i].data_pad);
541 vol->upd_marker = vtbl[i].upd_marker;
542 vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
543 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
544 vol->name_len = be16_to_cpu(vtbl[i].name_len);
545 vol->usable_leb_size = ubi->leb_size - vol->data_pad;
546 memcpy(vol->name, vtbl[i].name, vol->name_len);
547 vol->name[vol->name_len] = '\0';
548 vol->vol_id = i;
549
550 if (vtbl[i].flags & UBI_VTBL_SKIP_CRC_CHECK_FLG)
551 vol->skip_check = 1;
552
553 if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
554 /* Auto re-size flag may be set only for one volume */
555 if (ubi->autoresize_vol_id != -1) {
556 ubi_err(ubi, "more than one auto-resize volume (%d and %d)",
557 ubi->autoresize_vol_id, i);
558 kfree(vol);
559 return -EINVAL;
560 }
561
562 ubi->autoresize_vol_id = i;
563 }
564
565 ubi_assert(!ubi->volumes[i]);
566 ubi->volumes[i] = vol;
567 ubi->vol_count += 1;
568 vol->ubi = ubi;
569 reserved_pebs += vol->reserved_pebs;
570
571 /*
572 * We use ubi->peb_count and not vol->reserved_pebs because
573 * we want to keep the code simple. Otherwise we'd have to
574 * resize/check the bitmap upon volume resize too.
575 * Allocating a few bytes more does not hurt.
576 */
577 err = ubi_fastmap_init_checkmap(vol, ubi->peb_count);
578 if (err)
579 return err;
580
581 /*
582 * In case of dynamic volume UBI knows nothing about how many
583 * data is stored there. So assume the whole volume is used.
584 */
585 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
586 vol->used_ebs = vol->reserved_pebs;
587 vol->last_eb_bytes = vol->usable_leb_size;
588 vol->used_bytes =
589 (long long)vol->used_ebs * vol->usable_leb_size;
590 continue;
591 }
592
593 /* Static volumes only */
594 av = ubi_find_av(ai, i);
595 if (!av || !av->leb_count) {
596 /*
597 * No eraseblocks belonging to this volume found. We
598 * don't actually know whether this static volume is
599 * completely corrupted or just contains no data. And
600 * we cannot know this as long as data size is not
601 * stored on flash. So we just assume the volume is
602 * empty. FIXME: this should be handled.
603 */
604 continue;
605 }
606
607 if (av->leb_count != av->used_ebs) {
608 /*
609 * We found a static volume which misses several
610 * eraseblocks. Treat it as corrupted.
611 */
612 ubi_warn(ubi, "static volume %d misses %d LEBs - corrupted",
613 av->vol_id, av->used_ebs - av->leb_count);
614 vol->corrupted = 1;
615 continue;
616 }
617
618 vol->used_ebs = av->used_ebs;
619 vol->used_bytes =
620 (long long)(vol->used_ebs - 1) * vol->usable_leb_size;
621 vol->used_bytes += av->last_data_size;
622 vol->last_eb_bytes = av->last_data_size;
623 }
624
625 /* And add the layout volume */
626 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
627 if (!vol)
628 return -ENOMEM;
629
630 vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
631 vol->alignment = UBI_LAYOUT_VOLUME_ALIGN;
632 vol->vol_type = UBI_DYNAMIC_VOLUME;
633 vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
634 memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
635 vol->usable_leb_size = ubi->leb_size;
636 vol->used_ebs = vol->reserved_pebs;
637 vol->last_eb_bytes = vol->reserved_pebs;
638 vol->used_bytes =
639 (long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
640 vol->vol_id = UBI_LAYOUT_VOLUME_ID;
641 vol->ref_count = 1;
642
643 ubi_assert(!ubi->volumes[i]);
644 ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
645 reserved_pebs += vol->reserved_pebs;
646 ubi->vol_count += 1;
647 vol->ubi = ubi;
648 err = ubi_fastmap_init_checkmap(vol, UBI_LAYOUT_VOLUME_EBS);
649 if (err)
650 return err;
651
652 if (reserved_pebs > ubi->avail_pebs) {
653 ubi_err(ubi, "not enough PEBs, required %d, available %d",
654 reserved_pebs, ubi->avail_pebs);
655 if (ubi->corr_peb_count)
656 ubi_err(ubi, "%d PEBs are corrupted and not used",
657 ubi->corr_peb_count);
658 return -ENOSPC;
659 }
660 ubi->rsvd_pebs += reserved_pebs;
661 ubi->avail_pebs -= reserved_pebs;
662
663 return 0;
664 }
665
666 /**
667 * check_av - check volume attaching information.
668 * @vol: UBI volume description object
669 * @av: volume attaching information
670 *
671 * This function returns zero if the volume attaching information is consistent
672 * to the data read from the volume tabla, and %-EINVAL if not.
673 */
674 static int check_av(const struct ubi_volume *vol,
675 const struct ubi_ainf_volume *av)
676 {
677 int err;
678
679 if (av->highest_lnum >= vol->reserved_pebs) {
680 err = 1;
681 goto bad;
682 }
683 if (av->leb_count > vol->reserved_pebs) {
684 err = 2;
685 goto bad;
686 }
687 if (av->vol_type != vol->vol_type) {
688 err = 3;
689 goto bad;
690 }
691 if (av->used_ebs > vol->reserved_pebs) {
692 err = 4;
693 goto bad;
694 }
695 if (av->data_pad != vol->data_pad) {
696 err = 5;
697 goto bad;
698 }
699 return 0;
700
701 bad:
702 ubi_err(vol->ubi, "bad attaching information, error %d", err);
703 ubi_dump_av(av);
704 ubi_dump_vol_info(vol);
705 return -EINVAL;
706 }
707
708 /**
709 * check_attaching_info - check that attaching information.
710 * @ubi: UBI device description object
711 * @ai: attaching information
712 *
713 * Even though we protect on-flash data by CRC checksums, we still don't trust
714 * the media. This function ensures that attaching information is consistent to
715 * the information read from the volume table. Returns zero if the attaching
716 * information is OK and %-EINVAL if it is not.
717 */
718 static int check_attaching_info(const struct ubi_device *ubi,
719 struct ubi_attach_info *ai)
720 {
721 int err, i;
722 struct ubi_ainf_volume *av;
723 struct ubi_volume *vol;
724
725 if (ai->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
726 ubi_err(ubi, "found %d volumes while attaching, maximum is %d + %d",
727 ai->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
728 return -EINVAL;
729 }
730
731 if (ai->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT &&
732 ai->highest_vol_id < UBI_INTERNAL_VOL_START) {
733 ubi_err(ubi, "too large volume ID %d found",
734 ai->highest_vol_id);
735 return -EINVAL;
736 }
737
738 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
739 cond_resched();
740
741 av = ubi_find_av(ai, i);
742 vol = ubi->volumes[i];
743 if (!vol) {
744 if (av)
745 ubi_remove_av(ai, av);
746 continue;
747 }
748
749 if (vol->reserved_pebs == 0) {
750 ubi_assert(i < ubi->vtbl_slots);
751
752 if (!av)
753 continue;
754
755 /*
756 * During attaching we found a volume which does not
757 * exist according to the information in the volume
758 * table. This must have happened due to an unclean
759 * reboot while the volume was being removed. Discard
760 * these eraseblocks.
761 */
762 ubi_msg(ubi, "finish volume %d removal", av->vol_id);
763 ubi_remove_av(ai, av);
764 } else if (av) {
765 err = check_av(vol, av);
766 if (err)
767 return err;
768 }
769 }
770
771 return 0;
772 }
773
774 /**
775 * ubi_read_volume_table - read the volume table.
776 * @ubi: UBI device description object
777 * @ai: attaching information
778 *
779 * This function reads volume table, checks it, recover from errors if needed,
780 * or creates it if needed. Returns zero in case of success and a negative
781 * error code in case of failure.
782 */
783 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_attach_info *ai)
784 {
785 int i, err;
786 struct ubi_ainf_volume *av;
787
788 empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
789
790 /*
791 * The number of supported volumes is limited by the eraseblock size
792 * and by the UBI_MAX_VOLUMES constant.
793 */
794 ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
795 if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
796 ubi->vtbl_slots = UBI_MAX_VOLUMES;
797
798 ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
799 ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);
800
801 av = ubi_find_av(ai, UBI_LAYOUT_VOLUME_ID);
802 if (!av) {
803 /*
804 * No logical eraseblocks belonging to the layout volume were
805 * found. This could mean that the flash is just empty. In
806 * this case we create empty layout volume.
807 *
808 * But if flash is not empty this must be a corruption or the
809 * MTD device just contains garbage.
810 */
811 if (ai->is_empty) {
812 ubi->vtbl = create_empty_lvol(ubi, ai);
813 if (IS_ERR(ubi->vtbl))
814 return PTR_ERR(ubi->vtbl);
815 } else {
816 ubi_err(ubi, "the layout volume was not found");
817 return -EINVAL;
818 }
819 } else {
820 if (av->leb_count > UBI_LAYOUT_VOLUME_EBS) {
821 /* This must not happen with proper UBI images */
822 ubi_err(ubi, "too many LEBs (%d) in layout volume",
823 av->leb_count);
824 return -EINVAL;
825 }
826
827 ubi->vtbl = process_lvol(ubi, ai, av);
828 if (IS_ERR(ubi->vtbl))
829 return PTR_ERR(ubi->vtbl);
830 }
831
832 ubi->avail_pebs = ubi->good_peb_count - ubi->corr_peb_count;
833
834 /*
835 * The layout volume is OK, initialize the corresponding in-RAM data
836 * structures.
837 */
838 err = init_volumes(ubi, ai, ubi->vtbl);
839 if (err)
840 goto out_free;
841
842 /*
843 * Make sure that the attaching information is consistent to the
844 * information stored in the volume table.
845 */
846 err = check_attaching_info(ubi, ai);
847 if (err)
848 goto out_free;
849
850 return 0;
851
852 out_free:
853 vfree(ubi->vtbl);
854 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
855 ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
856 kfree(ubi->volumes[i]);
857 ubi->volumes[i] = NULL;
858 }
859 return err;
860 }
861
862 /**
863 * self_vtbl_check - check volume table.
864 * @ubi: UBI device description object
865 */
866 static void self_vtbl_check(const struct ubi_device *ubi)
867 {
868 if (!ubi_dbg_chk_gen(ubi))
869 return;
870
871 if (vtbl_check(ubi, ubi->vtbl)) {
872 ubi_err(ubi, "self-check failed");
873 BUG();
874 }
875 }