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