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. Note,
34 * nowadays we use the atomic LEB change operation when updating the volume
35 * table, so we do not really need 2 LEBs anymore, but we preserve the older
36 * design for the backward compatibility reasons.
37 *
38 * When the volume table is changed, it is first changed in RAM. Then LEB 0 is
39 * erased, and the updated volume table is written back to LEB 0. Then same for
40 * LEB 1. This scheme guarantees recoverability from unclean reboots.
41 *
42 * In this UBI implementation the on-flash volume table does not contain any
43 * information about how much data static volumes contain.
44 *
45 * But it would still be beneficial to store this information in the volume
46 * table. For example, suppose we have a static volume X, and all its physical
47 * eraseblocks became bad for some reasons. Suppose we are attaching the
48 * corresponding MTD device, for some reason we find no logical eraseblocks
49 * corresponding to the volume X. According to the volume table volume X does
50 * exist. So we don't know whether it is just empty or all its physical
51 * eraseblocks went bad. So we cannot alarm the user properly.
52 *
53 * The volume table also stores so-called "update marker", which is used for
54 * volume updates. Before updating the volume, the update marker is set, and
55 * after the update operation is finished, the update marker is cleared. So if
56 * the update operation was interrupted (e.g. by an unclean reboot) - the
57 * update marker is still there and we know that the volume's contents is
58 * damaged.
59 */
60
61 #include <linux/crc32.h>
62 #include <linux/err.h>
63 #include <linux/slab.h>
64 #include <asm/div64.h>
65 #include "ubi.h"
66
67 static void self_vtbl_check(const struct ubi_device *ubi);
68
69 /* Empty volume table record */
70 static struct ubi_vtbl_record empty_vtbl_record;
71
72 /**
73 * ubi_change_vtbl_record - change volume table record.
74 * @ubi: UBI device description object
75 * @idx: table index to change
76 * @vtbl_rec: new volume table record
77 *
78 * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
79 * volume table record is written. The caller does not have to calculate CRC of
80 * the record as it is done by this function. Returns zero in case of success
81 * and a negative error code in case of failure.
82 */
ubi_change_vtbl_record(struct ubi_device * ubi,int idx,struct ubi_vtbl_record * vtbl_rec)83 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
84 struct ubi_vtbl_record *vtbl_rec)
85 {
86 int i, err;
87 uint32_t crc;
88 struct ubi_volume *layout_vol;
89
90 ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
91 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
92
93 if (!vtbl_rec)
94 vtbl_rec = &empty_vtbl_record;
95 else {
96 crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC);
97 vtbl_rec->crc = cpu_to_be32(crc);
98 }
99
100 memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
101 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
102 err = ubi_eba_atomic_leb_change(ubi, layout_vol, i, ubi->vtbl,
103 ubi->vtbl_size);
104 if (err)
105 return err;
106 }
107
108 self_vtbl_check(ubi);
109 return 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 */
ubi_vtbl_rename_volumes(struct ubi_device * ubi,struct list_head * rename_list)121 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
122 struct list_head *rename_list)
123 {
124 int i, err;
125 struct ubi_rename_entry *re;
126 struct ubi_volume *layout_vol;
127
128 list_for_each_entry(re, rename_list, list) {
129 uint32_t crc;
130 struct ubi_volume *vol = re->desc->vol;
131 struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol->vol_id];
132
133 if (re->remove) {
134 memcpy(vtbl_rec, &empty_vtbl_record,
135 sizeof(struct ubi_vtbl_record));
136 continue;
137 }
138
139 vtbl_rec->name_len = cpu_to_be16(re->new_name_len);
140 memcpy(vtbl_rec->name, re->new_name, re->new_name_len);
141 memset(vtbl_rec->name + re->new_name_len, 0,
142 UBI_VOL_NAME_MAX + 1 - re->new_name_len);
143 crc = crc32(UBI_CRC32_INIT, vtbl_rec,
144 UBI_VTBL_RECORD_SIZE_CRC);
145 vtbl_rec->crc = cpu_to_be32(crc);
146 }
147
148 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
149 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
150 err = ubi_eba_atomic_leb_change(ubi, layout_vol, i, ubi->vtbl,
151 ubi->vtbl_size);
152 if (err)
153 return err;
154 }
155
156 return 0;
157 }
158
159 /**
160 * vtbl_check - check if volume table is not corrupted and sensible.
161 * @ubi: UBI device description object
162 * @vtbl: volume table
163 *
164 * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
165 * and %-EINVAL if it contains inconsistent data.
166 */
vtbl_check(const struct ubi_device * ubi,const struct ubi_vtbl_record * vtbl)167 static int vtbl_check(const struct ubi_device *ubi,
168 const struct ubi_vtbl_record *vtbl)
169 {
170 int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
171 int upd_marker, err;
172 uint32_t crc;
173 const char *name;
174
175 for (i = 0; i < ubi->vtbl_slots; i++) {
176 cond_resched();
177
178 reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
179 alignment = be32_to_cpu(vtbl[i].alignment);
180 data_pad = be32_to_cpu(vtbl[i].data_pad);
181 upd_marker = vtbl[i].upd_marker;
182 vol_type = vtbl[i].vol_type;
183 name_len = be16_to_cpu(vtbl[i].name_len);
184 name = &vtbl[i].name[0];
185
186 crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
187 if (be32_to_cpu(vtbl[i].crc) != crc) {
188 ubi_err(ubi, "bad CRC at record %u: %#08x, not %#08x",
189 i, crc, be32_to_cpu(vtbl[i].crc));
190 ubi_dump_vtbl_record(&vtbl[i], i);
191 return 1;
192 }
193
194 if (reserved_pebs == 0) {
195 if (memcmp(&vtbl[i], &empty_vtbl_record,
196 UBI_VTBL_RECORD_SIZE)) {
197 err = 2;
198 goto bad;
199 }
200 continue;
201 }
202
203 if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
204 name_len < 0) {
205 err = 3;
206 goto bad;
207 }
208
209 if (alignment > ubi->leb_size || alignment == 0) {
210 err = 4;
211 goto bad;
212 }
213
214 n = alignment & (ubi->min_io_size - 1);
215 if (alignment != 1 && n) {
216 err = 5;
217 goto bad;
218 }
219
220 n = ubi->leb_size % alignment;
221 if (data_pad != n) {
222 ubi_err(ubi, "bad data_pad, has to be %d", n);
223 err = 6;
224 goto bad;
225 }
226
227 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
228 err = 7;
229 goto bad;
230 }
231
232 if (upd_marker != 0 && upd_marker != 1) {
233 err = 8;
234 goto bad;
235 }
236
237 if (reserved_pebs > ubi->good_peb_count) {
238 ubi_err(ubi, "too large reserved_pebs %d, good PEBs %d",
239 reserved_pebs, ubi->good_peb_count);
240 err = 9;
241 goto bad;
242 }
243
244 if (name_len > UBI_VOL_NAME_MAX) {
245 err = 10;
246 goto bad;
247 }
248
249 if (name[0] == '\0') {
250 err = 11;
251 goto bad;
252 }
253
254 if (name_len != strnlen(name, name_len + 1)) {
255 err = 12;
256 goto bad;
257 }
258 }
259
260 /* Checks that all names are unique */
261 for (i = 0; i < ubi->vtbl_slots - 1; i++) {
262 for (n = i + 1; n < ubi->vtbl_slots; n++) {
263 int len1 = be16_to_cpu(vtbl[i].name_len);
264 int len2 = be16_to_cpu(vtbl[n].name_len);
265
266 if (len1 > 0 && len1 == len2 &&
267 !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
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 */
create_vtbl(struct ubi_device * ubi,struct ubi_attach_info * ai,int copy,void * vtbl)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 */
process_lvol(struct ubi_device * ubi,struct ubi_attach_info * ai,struct ubi_ainf_volume * av)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 */
create_empty_lvol(struct ubi_device * ubi,struct ubi_attach_info * ai)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 */
init_volumes(struct ubi_device * ubi,const struct ubi_attach_info * ai,const struct ubi_vtbl_record * vtbl)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 return -ENOSPC;
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 */
check_av(const struct ubi_volume * vol,const struct ubi_ainf_volume * av)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 */
check_attaching_info(const struct ubi_device * ubi,struct ubi_attach_info * ai)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 */
ubi_read_volume_table(struct ubi_device * ubi,struct ubi_attach_info * ai)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 */
self_vtbl_check(const struct ubi_device * ubi)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