1 /*
2 * Copyright (c) International Business Machines Corp., 2006
3 * Copyright (c) Nokia Corporation, 2006, 2007
4 *
5 * SPDX-License-Identifier: GPL-2.0+
6 *
7 * Author: Artem Bityutskiy (Битюцкий Артём)
8 */
9
10 /*
11 * This file includes volume table manipulation code. The volume table is an
12 * on-flash table containing volume meta-data like name, number of reserved
13 * physical eraseblocks, type, etc. The volume table is stored in the so-called
14 * "layout volume".
15 *
16 * The layout volume is an internal volume which is organized as follows. It
17 * consists of two logical eraseblocks - LEB 0 and LEB 1. Each logical
18 * eraseblock stores one volume table copy, i.e. LEB 0 and LEB 1 duplicate each
19 * other. This redundancy guarantees robustness to unclean reboots. The volume
20 * table is basically an array of volume table records. Each record contains
21 * full information about the volume and protected by a CRC checksum. Note,
22 * nowadays we use the atomic LEB change operation when updating the volume
23 * table, so we do not really need 2 LEBs anymore, but we preserve the older
24 * design for the backward compatibility reasons.
25 *
26 * When the volume table is changed, it is first changed in RAM. Then LEB 0 is
27 * erased, and the updated volume table is written back to LEB 0. Then same for
28 * LEB 1. This scheme guarantees recoverability from unclean reboots.
29 *
30 * In this UBI implementation the on-flash volume table does not contain any
31 * information about how much data static volumes contain.
32 *
33 * But it would still be beneficial to store this information in the volume
34 * table. For example, suppose we have a static volume X, and all its physical
35 * eraseblocks became bad for some reasons. Suppose we are attaching the
36 * corresponding MTD device, for some reason we find no logical eraseblocks
37 * corresponding to the volume X. According to the volume table volume X does
38 * exist. So we don't know whether it is just empty or all its physical
39 * eraseblocks went bad. So we cannot alarm the user properly.
40 *
41 * The volume table also stores so-called "update marker", which is used for
42 * volume updates. Before updating the volume, the update marker is set, and
43 * after the update operation is finished, the update marker is cleared. So if
44 * the update operation was interrupted (e.g. by an unclean reboot) - the
45 * update marker is still there and we know that the volume's contents is
46 * damaged.
47 */
48
49 #ifndef __UBOOT__
50 #include <linux/crc32.h>
51 #include <linux/err.h>
52 #include <linux/slab.h>
53 #include <asm/div64.h>
54 #else
55 #include <ubi_uboot.h>
56 #endif
57
58 #include <linux/err.h>
59 #include "ubi.h"
60
61 static void self_vtbl_check(const struct ubi_device *ubi);
62
63 /* Empty volume table record */
64 static struct ubi_vtbl_record empty_vtbl_record;
65
66 /**
67 * ubi_update_layout_vol - helper for updatting layout volumes on flash
68 * @ubi: UBI device description object
69 */
ubi_update_layout_vol(struct ubi_device * ubi)70 static int ubi_update_layout_vol(struct ubi_device *ubi)
71 {
72 struct ubi_volume *layout_vol;
73 int i, err;
74
75 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
76 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
77 err = ubi_eba_atomic_leb_change(ubi, layout_vol, i, ubi->vtbl,
78 ubi->vtbl_size);
79 if (err)
80 return err;
81 }
82
83 return 0;
84 }
85
86 /**
87 * ubi_change_vtbl_record - change volume table record.
88 * @ubi: UBI device description object
89 * @idx: table index to change
90 * @vtbl_rec: new volume table record
91 *
92 * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
93 * volume table record is written. The caller does not have to calculate CRC of
94 * the record as it is done by this function. Returns zero in case of success
95 * and a negative error code in case of failure.
96 */
ubi_change_vtbl_record(struct ubi_device * ubi,int idx,struct ubi_vtbl_record * vtbl_rec)97 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
98 struct ubi_vtbl_record *vtbl_rec)
99 {
100 int err;
101 uint32_t crc;
102
103 ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
104
105 if (!vtbl_rec)
106 vtbl_rec = &empty_vtbl_record;
107 else {
108 crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC);
109 vtbl_rec->crc = cpu_to_be32(crc);
110 }
111
112 memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
113 err = ubi_update_layout_vol(ubi);
114
115 self_vtbl_check(ubi);
116 return err ? err : 0;
117 }
118
119 /**
120 * ubi_vtbl_rename_volumes - rename UBI volumes in the volume table.
121 * @ubi: UBI device description object
122 * @rename_list: list of &struct ubi_rename_entry objects
123 *
124 * This function re-names multiple volumes specified in @req in the volume
125 * table. Returns zero in case of success and a negative error code in case of
126 * failure.
127 */
ubi_vtbl_rename_volumes(struct ubi_device * ubi,struct list_head * rename_list)128 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
129 struct list_head *rename_list)
130 {
131 struct ubi_rename_entry *re;
132
133 list_for_each_entry(re, rename_list, list) {
134 uint32_t crc;
135 struct ubi_volume *vol = re->desc->vol;
136 struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol->vol_id];
137
138 if (re->remove) {
139 memcpy(vtbl_rec, &empty_vtbl_record,
140 sizeof(struct ubi_vtbl_record));
141 continue;
142 }
143
144 vtbl_rec->name_len = cpu_to_be16(re->new_name_len);
145 memcpy(vtbl_rec->name, re->new_name, re->new_name_len);
146 memset(vtbl_rec->name + re->new_name_len, 0,
147 UBI_VOL_NAME_MAX + 1 - re->new_name_len);
148 crc = crc32(UBI_CRC32_INIT, vtbl_rec,
149 UBI_VTBL_RECORD_SIZE_CRC);
150 vtbl_rec->crc = cpu_to_be32(crc);
151 }
152
153 return ubi_update_layout_vol(ubi);
154 }
155
156 /**
157 * vtbl_check - check if volume table is not corrupted and sensible.
158 * @ubi: UBI device description object
159 * @vtbl: volume table
160 *
161 * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
162 * and %-EINVAL if it contains inconsistent data.
163 */
vtbl_check(const struct ubi_device * ubi,const struct ubi_vtbl_record * vtbl)164 static int vtbl_check(const struct ubi_device *ubi,
165 const struct ubi_vtbl_record *vtbl)
166 {
167 int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
168 int upd_marker, err;
169 uint32_t crc;
170 const char *name;
171
172 for (i = 0; i < ubi->vtbl_slots; i++) {
173 cond_resched();
174
175 reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
176 alignment = be32_to_cpu(vtbl[i].alignment);
177 data_pad = be32_to_cpu(vtbl[i].data_pad);
178 upd_marker = vtbl[i].upd_marker;
179 vol_type = vtbl[i].vol_type;
180 name_len = be16_to_cpu(vtbl[i].name_len);
181 name = &vtbl[i].name[0];
182
183 crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
184 if (be32_to_cpu(vtbl[i].crc) != crc) {
185 ubi_err(ubi, "bad CRC at record %u: %#08x, not %#08x",
186 i, crc, be32_to_cpu(vtbl[i].crc));
187 ubi_dump_vtbl_record(&vtbl[i], i);
188 return 1;
189 }
190
191 if (reserved_pebs == 0) {
192 if (memcmp(&vtbl[i], &empty_vtbl_record,
193 UBI_VTBL_RECORD_SIZE)) {
194 err = 2;
195 goto bad;
196 }
197 continue;
198 }
199
200 if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
201 name_len < 0) {
202 err = 3;
203 goto bad;
204 }
205
206 if (alignment > ubi->leb_size || alignment == 0) {
207 err = 4;
208 goto bad;
209 }
210
211 n = alignment & (ubi->min_io_size - 1);
212 if (alignment != 1 && n) {
213 err = 5;
214 goto bad;
215 }
216
217 n = ubi->leb_size % alignment;
218 if (data_pad != n) {
219 ubi_err(ubi, "bad data_pad, has to be %d", n);
220 err = 6;
221 goto bad;
222 }
223
224 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
225 err = 7;
226 goto bad;
227 }
228
229 if (upd_marker != 0 && upd_marker != 1) {
230 err = 8;
231 goto bad;
232 }
233
234 if (reserved_pebs > ubi->good_peb_count) {
235 ubi_err(ubi, "too large reserved_pebs %d, good PEBs %d",
236 reserved_pebs, ubi->good_peb_count);
237 err = 9;
238 goto bad;
239 }
240
241 if (name_len > UBI_VOL_NAME_MAX) {
242 err = 10;
243 goto bad;
244 }
245
246 if (name[0] == '\0') {
247 err = 11;
248 goto bad;
249 }
250
251 if (name_len != strnlen(name, name_len + 1)) {
252 err = 12;
253 goto bad;
254 }
255 }
256
257 /* Checks that all names are unique */
258 for (i = 0; i < ubi->vtbl_slots - 1; i++) {
259 for (n = i + 1; n < ubi->vtbl_slots; n++) {
260 int len1 = be16_to_cpu(vtbl[i].name_len);
261 int len2 = be16_to_cpu(vtbl[n].name_len);
262
263 if (len1 > 0 && len1 == len2 &&
264 #ifndef __UBOOT__
265 !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
266 #else
267 !strncmp((char *)vtbl[i].name, vtbl[n].name, len1)) {
268 #endif
269 ubi_err(ubi, "volumes %d and %d have the same name \"%s\"",
270 i, n, vtbl[i].name);
271 ubi_dump_vtbl_record(&vtbl[i], i);
272 ubi_dump_vtbl_record(&vtbl[n], n);
273 return -EINVAL;
274 }
275 }
276 }
277
278 return 0;
279
280 bad:
281 ubi_err(ubi, "volume table check failed: record %d, error %d", i, err);
282 ubi_dump_vtbl_record(&vtbl[i], i);
283 return -EINVAL;
284 }
285
286 /**
287 * create_vtbl - create a copy of volume table.
288 * @ubi: UBI device description object
289 * @ai: attaching information
290 * @copy: number of the volume table copy
291 * @vtbl: contents of the volume table
292 *
293 * This function returns zero in case of success and a negative error code in
294 * case of failure.
295 */
296 static int create_vtbl(struct ubi_device *ubi, struct ubi_attach_info *ai,
297 int copy, void *vtbl)
298 {
299 int err, tries = 0;
300 struct ubi_vid_hdr *vid_hdr;
301 struct ubi_ainf_peb *new_aeb;
302
303 dbg_gen("create volume table (copy #%d)", copy + 1);
304
305 vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
306 if (!vid_hdr)
307 return -ENOMEM;
308
309 retry:
310 new_aeb = ubi_early_get_peb(ubi, ai);
311 if (IS_ERR(new_aeb)) {
312 err = PTR_ERR(new_aeb);
313 goto out_free;
314 }
315
316 vid_hdr->vol_type = UBI_LAYOUT_VOLUME_TYPE;
317 vid_hdr->vol_id = cpu_to_be32(UBI_LAYOUT_VOLUME_ID);
318 vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT;
319 vid_hdr->data_size = vid_hdr->used_ebs =
320 vid_hdr->data_pad = cpu_to_be32(0);
321 vid_hdr->lnum = cpu_to_be32(copy);
322 vid_hdr->sqnum = cpu_to_be64(++ai->max_sqnum);
323
324 /* The EC header is already there, write the VID header */
325 err = ubi_io_write_vid_hdr(ubi, new_aeb->pnum, vid_hdr);
326 if (err)
327 goto write_error;
328
329 /* Write the layout volume contents */
330 err = ubi_io_write_data(ubi, vtbl, new_aeb->pnum, 0, ubi->vtbl_size);
331 if (err)
332 goto write_error;
333
334 /*
335 * And add it to the attaching information. Don't delete the old version
336 * of this LEB as it will be deleted and freed in 'ubi_add_to_av()'.
337 */
338 err = ubi_add_to_av(ubi, ai, new_aeb->pnum, new_aeb->ec, vid_hdr, 0);
339 kmem_cache_free(ai->aeb_slab_cache, new_aeb);
340 ubi_free_vid_hdr(ubi, vid_hdr);
341 return err;
342
343 write_error:
344 if (err == -EIO && ++tries <= 5) {
345 /*
346 * Probably this physical eraseblock went bad, try to pick
347 * another one.
348 */
349 list_add(&new_aeb->u.list, &ai->erase);
350 goto retry;
351 }
352 kmem_cache_free(ai->aeb_slab_cache, new_aeb);
353 out_free:
354 ubi_free_vid_hdr(ubi, vid_hdr);
355 return err;
356
357 }
358
359 /**
360 * process_lvol - process the layout volume.
361 * @ubi: UBI device description object
362 * @ai: attaching information
363 * @av: layout volume attaching information
364 *
365 * This function is responsible for reading the layout volume, ensuring it is
366 * not corrupted, and recovering from corruptions if needed. Returns volume
367 * table in case of success and a negative error code in case of failure.
368 */
369 static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
370 struct ubi_attach_info *ai,
371 struct ubi_ainf_volume *av)
372 {
373 int err;
374 struct rb_node *rb;
375 struct ubi_ainf_peb *aeb;
376 struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL };
377 int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1};
378
379 /*
380 * UBI goes through the following steps when it changes the layout
381 * volume:
382 * a. erase LEB 0;
383 * b. write new data to LEB 0;
384 * c. erase LEB 1;
385 * d. write new data to LEB 1.
386 *
387 * Before the change, both LEBs contain the same data.
388 *
389 * Due to unclean reboots, the contents of LEB 0 may be lost, but there
390 * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not.
391 * Similarly, LEB 1 may be lost, but there should be LEB 0. And
392 * finally, unclean reboots may result in a situation when neither LEB
393 * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB
394 * 0 contains more recent information.
395 *
396 * So the plan is to first check LEB 0. Then
397 * a. if LEB 0 is OK, it must be containing the most recent data; then
398 * we compare it with LEB 1, and if they are different, we copy LEB
399 * 0 to LEB 1;
400 * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1
401 * to LEB 0.
402 */
403
404 dbg_gen("check layout volume");
405
406 /* Read both LEB 0 and LEB 1 into memory */
407 ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
408 leb[aeb->lnum] = vzalloc(ubi->vtbl_size);
409 if (!leb[aeb->lnum]) {
410 err = -ENOMEM;
411 goto out_free;
412 }
413
414 err = ubi_io_read_data(ubi, leb[aeb->lnum], aeb->pnum, 0,
415 ubi->vtbl_size);
416 if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err))
417 /*
418 * Scrub the PEB later. Note, -EBADMSG indicates an
419 * uncorrectable ECC error, but we have our own CRC and
420 * the data will be checked later. If the data is OK,
421 * the PEB will be scrubbed (because we set
422 * aeb->scrub). If the data is not OK, the contents of
423 * the PEB will be recovered from the second copy, and
424 * aeb->scrub will be cleared in
425 * 'ubi_add_to_av()'.
426 */
427 aeb->scrub = 1;
428 else if (err)
429 goto out_free;
430 }
431
432 err = -EINVAL;
433 if (leb[0]) {
434 leb_corrupted[0] = vtbl_check(ubi, leb[0]);
435 if (leb_corrupted[0] < 0)
436 goto out_free;
437 }
438
439 if (!leb_corrupted[0]) {
440 /* LEB 0 is OK */
441 if (leb[1])
442 leb_corrupted[1] = memcmp(leb[0], leb[1],
443 ubi->vtbl_size);
444 if (leb_corrupted[1]) {
445 ubi_warn(ubi, "volume table copy #2 is corrupted");
446 err = create_vtbl(ubi, ai, 1, leb[0]);
447 if (err)
448 goto out_free;
449 ubi_msg(ubi, "volume table was restored");
450 }
451
452 /* Both LEB 1 and LEB 2 are OK and consistent */
453 vfree(leb[1]);
454 return leb[0];
455 } else {
456 /* LEB 0 is corrupted or does not exist */
457 if (leb[1]) {
458 leb_corrupted[1] = vtbl_check(ubi, leb[1]);
459 if (leb_corrupted[1] < 0)
460 goto out_free;
461 }
462 if (leb_corrupted[1]) {
463 /* Both LEB 0 and LEB 1 are corrupted */
464 ubi_err(ubi, "both volume tables are corrupted");
465 goto out_free;
466 }
467
468 ubi_warn(ubi, "volume table copy #1 is corrupted");
469 err = create_vtbl(ubi, ai, 0, leb[1]);
470 if (err)
471 goto out_free;
472 ubi_msg(ubi, "volume table was restored");
473
474 vfree(leb[0]);
475 return leb[1];
476 }
477
478 out_free:
479 vfree(leb[0]);
480 vfree(leb[1]);
481 return ERR_PTR(err);
482 }
483
484 /**
485 * create_empty_lvol - create empty layout volume.
486 * @ubi: UBI device description object
487 * @ai: attaching information
488 *
489 * This function returns volume table contents in case of success and a
490 * negative error code in case of failure.
491 */
492 static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
493 struct ubi_attach_info *ai)
494 {
495 int i;
496 struct ubi_vtbl_record *vtbl;
497
498 vtbl = vzalloc(ubi->vtbl_size);
499 if (!vtbl)
500 return ERR_PTR(-ENOMEM);
501
502 for (i = 0; i < ubi->vtbl_slots; i++)
503 memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);
504
505 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
506 int err;
507
508 err = create_vtbl(ubi, ai, i, vtbl);
509 if (err) {
510 vfree(vtbl);
511 return ERR_PTR(err);
512 }
513 }
514
515 return vtbl;
516 }
517
518 /**
519 * init_volumes - initialize volume information for existing volumes.
520 * @ubi: UBI device description object
521 * @ai: scanning information
522 * @vtbl: volume table
523 *
524 * This function allocates volume description objects for existing volumes.
525 * Returns zero in case of success and a negative error code in case of
526 * failure.
527 */
528 static int init_volumes(struct ubi_device *ubi,
529 const struct ubi_attach_info *ai,
530 const struct ubi_vtbl_record *vtbl)
531 {
532 int i, reserved_pebs = 0;
533 struct ubi_ainf_volume *av;
534 struct ubi_volume *vol;
535
536 for (i = 0; i < ubi->vtbl_slots; i++) {
537 cond_resched();
538
539 if (be32_to_cpu(vtbl[i].reserved_pebs) == 0)
540 continue; /* Empty record */
541
542 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
543 if (!vol)
544 return -ENOMEM;
545
546 vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
547 vol->alignment = be32_to_cpu(vtbl[i].alignment);
548 vol->data_pad = be32_to_cpu(vtbl[i].data_pad);
549 vol->upd_marker = vtbl[i].upd_marker;
550 vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
551 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
552 vol->name_len = be16_to_cpu(vtbl[i].name_len);
553 vol->usable_leb_size = ubi->leb_size - vol->data_pad;
554 memcpy(vol->name, vtbl[i].name, vol->name_len);
555 vol->name[vol->name_len] = '\0';
556 vol->vol_id = i;
557
558 if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
559 /* Auto re-size flag may be set only for one volume */
560 if (ubi->autoresize_vol_id != -1) {
561 ubi_err(ubi, "more than one auto-resize volume (%d and %d)",
562 ubi->autoresize_vol_id, i);
563 kfree(vol);
564 return -EINVAL;
565 }
566
567 ubi->autoresize_vol_id = i;
568 }
569
570 ubi_assert(!ubi->volumes[i]);
571 ubi->volumes[i] = vol;
572 ubi->vol_count += 1;
573 vol->ubi = ubi;
574 reserved_pebs += vol->reserved_pebs;
575
576 /*
577 * In case of dynamic volume UBI knows nothing about how many
578 * data is stored there. So assume the whole volume is used.
579 */
580 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
581 vol->used_ebs = vol->reserved_pebs;
582 vol->last_eb_bytes = vol->usable_leb_size;
583 vol->used_bytes =
584 (long long)vol->used_ebs * vol->usable_leb_size;
585 continue;
586 }
587
588 /* Static volumes only */
589 av = ubi_find_av(ai, i);
590 if (!av || !av->leb_count) {
591 /*
592 * No eraseblocks belonging to this volume found. We
593 * don't actually know whether this static volume is
594 * completely corrupted or just contains no data. And
595 * we cannot know this as long as data size is not
596 * stored on flash. So we just assume the volume is
597 * empty. FIXME: this should be handled.
598 */
599 continue;
600 }
601
602 if (av->leb_count != av->used_ebs) {
603 /*
604 * We found a static volume which misses several
605 * eraseblocks. Treat it as corrupted.
606 */
607 ubi_warn(ubi, "static volume %d misses %d LEBs - corrupted",
608 av->vol_id, av->used_ebs - av->leb_count);
609 vol->corrupted = 1;
610 continue;
611 }
612
613 vol->used_ebs = av->used_ebs;
614 vol->used_bytes =
615 (long long)(vol->used_ebs - 1) * vol->usable_leb_size;
616 vol->used_bytes += av->last_data_size;
617 vol->last_eb_bytes = av->last_data_size;
618 }
619
620 /* And add the layout volume */
621 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
622 if (!vol)
623 return -ENOMEM;
624
625 vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
626 vol->alignment = UBI_LAYOUT_VOLUME_ALIGN;
627 vol->vol_type = UBI_DYNAMIC_VOLUME;
628 vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
629 memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
630 vol->usable_leb_size = ubi->leb_size;
631 vol->used_ebs = vol->reserved_pebs;
632 vol->last_eb_bytes = vol->reserved_pebs;
633 vol->used_bytes =
634 (long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
635 vol->vol_id = UBI_LAYOUT_VOLUME_ID;
636 vol->ref_count = 1;
637
638 ubi_assert(!ubi->volumes[i]);
639 ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
640 reserved_pebs += vol->reserved_pebs;
641 ubi->vol_count += 1;
642 vol->ubi = ubi;
643
644 if (reserved_pebs > ubi->avail_pebs) {
645 ubi_err(ubi, "not enough PEBs, required %d, available %d",
646 reserved_pebs, ubi->avail_pebs);
647 if (ubi->corr_peb_count)
648 ubi_err(ubi, "%d PEBs are corrupted and not used",
649 ubi->corr_peb_count);
650 }
651 ubi->rsvd_pebs += reserved_pebs;
652 ubi->avail_pebs -= reserved_pebs;
653
654 return 0;
655 }
656
657 /**
658 * check_av - check volume attaching information.
659 * @vol: UBI volume description object
660 * @av: volume attaching information
661 *
662 * This function returns zero if the volume attaching information is consistent
663 * to the data read from the volume tabla, and %-EINVAL if not.
664 */
665 static int check_av(const struct ubi_volume *vol,
666 const struct ubi_ainf_volume *av)
667 {
668 int err;
669
670 if (av->highest_lnum >= vol->reserved_pebs) {
671 err = 1;
672 goto bad;
673 }
674 if (av->leb_count > vol->reserved_pebs) {
675 err = 2;
676 goto bad;
677 }
678 if (av->vol_type != vol->vol_type) {
679 err = 3;
680 goto bad;
681 }
682 if (av->used_ebs > vol->reserved_pebs) {
683 err = 4;
684 goto bad;
685 }
686 if (av->data_pad != vol->data_pad) {
687 err = 5;
688 goto bad;
689 }
690 return 0;
691
692 bad:
693 ubi_err(vol->ubi, "bad attaching information, error %d", err);
694 ubi_dump_av(av);
695 ubi_dump_vol_info(vol);
696 return -EINVAL;
697 }
698
699 /**
700 * check_attaching_info - check that attaching information.
701 * @ubi: UBI device description object
702 * @ai: attaching information
703 *
704 * Even though we protect on-flash data by CRC checksums, we still don't trust
705 * the media. This function ensures that attaching information is consistent to
706 * the information read from the volume table. Returns zero if the attaching
707 * information is OK and %-EINVAL if it is not.
708 */
709 static int check_attaching_info(const struct ubi_device *ubi,
710 struct ubi_attach_info *ai)
711 {
712 int err, i;
713 struct ubi_ainf_volume *av;
714 struct ubi_volume *vol;
715
716 if (ai->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
717 ubi_err(ubi, "found %d volumes while attaching, maximum is %d + %d",
718 ai->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
719 return -EINVAL;
720 }
721
722 if (ai->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT &&
723 ai->highest_vol_id < UBI_INTERNAL_VOL_START) {
724 ubi_err(ubi, "too large volume ID %d found",
725 ai->highest_vol_id);
726 return -EINVAL;
727 }
728
729 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
730 cond_resched();
731
732 av = ubi_find_av(ai, i);
733 vol = ubi->volumes[i];
734 if (!vol) {
735 if (av)
736 ubi_remove_av(ai, av);
737 continue;
738 }
739
740 if (vol->reserved_pebs == 0) {
741 ubi_assert(i < ubi->vtbl_slots);
742
743 if (!av)
744 continue;
745
746 /*
747 * During attaching we found a volume which does not
748 * exist according to the information in the volume
749 * table. This must have happened due to an unclean
750 * reboot while the volume was being removed. Discard
751 * these eraseblocks.
752 */
753 ubi_msg(ubi, "finish volume %d removal", av->vol_id);
754 ubi_remove_av(ai, av);
755 } else if (av) {
756 err = check_av(vol, av);
757 if (err)
758 return err;
759 }
760 }
761
762 return 0;
763 }
764
765 /**
766 * ubi_read_volume_table - read the volume table.
767 * @ubi: UBI device description object
768 * @ai: attaching information
769 *
770 * This function reads volume table, checks it, recover from errors if needed,
771 * or creates it if needed. Returns zero in case of success and a negative
772 * error code in case of failure.
773 */
774 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_attach_info *ai)
775 {
776 int i, err;
777 struct ubi_ainf_volume *av;
778
779 empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
780
781 /*
782 * The number of supported volumes is limited by the eraseblock size
783 * and by the UBI_MAX_VOLUMES constant.
784 */
785 ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
786 if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
787 ubi->vtbl_slots = UBI_MAX_VOLUMES;
788
789 ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
790 ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);
791
792 av = ubi_find_av(ai, UBI_LAYOUT_VOLUME_ID);
793 if (!av) {
794 /*
795 * No logical eraseblocks belonging to the layout volume were
796 * found. This could mean that the flash is just empty. In
797 * this case we create empty layout volume.
798 *
799 * But if flash is not empty this must be a corruption or the
800 * MTD device just contains garbage.
801 */
802 if (ai->is_empty) {
803 ubi->vtbl = create_empty_lvol(ubi, ai);
804 if (IS_ERR(ubi->vtbl))
805 return PTR_ERR(ubi->vtbl);
806 } else {
807 ubi_err(ubi, "the layout volume was not found");
808 return -EINVAL;
809 }
810 } else {
811 if (av->leb_count > UBI_LAYOUT_VOLUME_EBS) {
812 /* This must not happen with proper UBI images */
813 ubi_err(ubi, "too many LEBs (%d) in layout volume",
814 av->leb_count);
815 return -EINVAL;
816 }
817
818 ubi->vtbl = process_lvol(ubi, ai, av);
819 if (IS_ERR(ubi->vtbl))
820 return PTR_ERR(ubi->vtbl);
821 }
822
823 ubi->avail_pebs = ubi->good_peb_count - ubi->corr_peb_count;
824
825 /*
826 * The layout volume is OK, initialize the corresponding in-RAM data
827 * structures.
828 */
829 err = init_volumes(ubi, ai, ubi->vtbl);
830 if (err)
831 goto out_free;
832
833 /*
834 * Make sure that the attaching information is consistent to the
835 * information stored in the volume table.
836 */
837 err = check_attaching_info(ubi, ai);
838 if (err)
839 goto out_free;
840
841 return 0;
842
843 out_free:
844 vfree(ubi->vtbl);
845 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
846 kfree(ubi->volumes[i]);
847 ubi->volumes[i] = NULL;
848 }
849 return err;
850 }
851
852 /**
853 * self_vtbl_check - check volume table.
854 * @ubi: UBI device description object
855 */
856 static void self_vtbl_check(const struct ubi_device *ubi)
857 {
858 if (!ubi_dbg_chk_gen(ubi))
859 return;
860
861 if (vtbl_check(ubi, ubi->vtbl)) {
862 ubi_err(ubi, "self-check failed");
863 BUG();
864 }
865 }
866