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_update_layout_vol - helper for updatting layout volumes on flash
74 * @ubi: UBI device description object
75 */
ubi_update_layout_vol(struct ubi_device * ubi)76 static int ubi_update_layout_vol(struct ubi_device *ubi)
77 {
78 struct ubi_volume *layout_vol;
79 int i, err;
80
81 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
82 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
83 err = ubi_eba_atomic_leb_change(ubi, layout_vol, i, ubi->vtbl,
84 ubi->vtbl_size);
85 if (err)
86 return err;
87 }
88
89 return 0;
90 }
91
92 /**
93 * ubi_change_vtbl_record - change volume table record.
94 * @ubi: UBI device description object
95 * @idx: table index to change
96 * @vtbl_rec: new volume table record
97 *
98 * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
99 * volume table record is written. The caller does not have to calculate CRC of
100 * the record as it is done by this function. Returns zero in case of success
101 * and a negative error code in case of failure.
102 */
ubi_change_vtbl_record(struct ubi_device * ubi,int idx,struct ubi_vtbl_record * vtbl_rec)103 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
104 struct ubi_vtbl_record *vtbl_rec)
105 {
106 int err;
107 uint32_t crc;
108
109 ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
110
111 if (!vtbl_rec)
112 vtbl_rec = &empty_vtbl_record;
113 else {
114 crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC);
115 vtbl_rec->crc = cpu_to_be32(crc);
116 }
117
118 memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
119 err = ubi_update_layout_vol(ubi);
120
121 self_vtbl_check(ubi);
122 return err ? err : 0;
123 }
124
125 /**
126 * ubi_vtbl_rename_volumes - rename UBI volumes in the volume table.
127 * @ubi: UBI device description object
128 * @rename_list: list of &struct ubi_rename_entry objects
129 *
130 * This function re-names multiple volumes specified in @req in the volume
131 * table. Returns zero in case of success and a negative error code in case of
132 * failure.
133 */
ubi_vtbl_rename_volumes(struct ubi_device * ubi,struct list_head * rename_list)134 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
135 struct list_head *rename_list)
136 {
137 struct ubi_rename_entry *re;
138
139 list_for_each_entry(re, rename_list, list) {
140 uint32_t crc;
141 struct ubi_volume *vol = re->desc->vol;
142 struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol->vol_id];
143
144 if (re->remove) {
145 memcpy(vtbl_rec, &empty_vtbl_record,
146 sizeof(struct ubi_vtbl_record));
147 continue;
148 }
149
150 vtbl_rec->name_len = cpu_to_be16(re->new_name_len);
151 memcpy(vtbl_rec->name, re->new_name, re->new_name_len);
152 memset(vtbl_rec->name + re->new_name_len, 0,
153 UBI_VOL_NAME_MAX + 1 - re->new_name_len);
154 crc = crc32(UBI_CRC32_INIT, vtbl_rec,
155 UBI_VTBL_RECORD_SIZE_CRC);
156 vtbl_rec->crc = cpu_to_be32(crc);
157 }
158
159 return ubi_update_layout_vol(ubi);
160 }
161
162 /**
163 * vtbl_check - check if volume table is not corrupted and sensible.
164 * @ubi: UBI device description object
165 * @vtbl: volume table
166 *
167 * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
168 * and %-EINVAL if it contains inconsistent data.
169 */
vtbl_check(const struct ubi_device * ubi,const struct ubi_vtbl_record * vtbl)170 static int vtbl_check(const struct ubi_device *ubi,
171 const struct ubi_vtbl_record *vtbl)
172 {
173 int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
174 int upd_marker, err;
175 uint32_t crc;
176 const char *name;
177
178 for (i = 0; i < ubi->vtbl_slots; i++) {
179 cond_resched();
180
181 reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
182 alignment = be32_to_cpu(vtbl[i].alignment);
183 data_pad = be32_to_cpu(vtbl[i].data_pad);
184 upd_marker = vtbl[i].upd_marker;
185 vol_type = vtbl[i].vol_type;
186 name_len = be16_to_cpu(vtbl[i].name_len);
187 name = &vtbl[i].name[0];
188
189 crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
190 if (be32_to_cpu(vtbl[i].crc) != crc) {
191 ubi_err(ubi, "bad CRC at record %u: %#08x, not %#08x",
192 i, crc, be32_to_cpu(vtbl[i].crc));
193 ubi_dump_vtbl_record(&vtbl[i], i);
194 return 1;
195 }
196
197 if (reserved_pebs == 0) {
198 if (memcmp(&vtbl[i], &empty_vtbl_record,
199 UBI_VTBL_RECORD_SIZE)) {
200 err = 2;
201 goto bad;
202 }
203 continue;
204 }
205
206 if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
207 name_len < 0) {
208 err = 3;
209 goto bad;
210 }
211
212 if (alignment > ubi->leb_size || alignment == 0) {
213 err = 4;
214 goto bad;
215 }
216
217 n = alignment & (ubi->min_io_size - 1);
218 if (alignment != 1 && n) {
219 err = 5;
220 goto bad;
221 }
222
223 n = ubi->leb_size % alignment;
224 if (data_pad != n) {
225 ubi_err(ubi, "bad data_pad, has to be %d", n);
226 err = 6;
227 goto bad;
228 }
229
230 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
231 err = 7;
232 goto bad;
233 }
234
235 if (upd_marker != 0 && upd_marker != 1) {
236 err = 8;
237 goto bad;
238 }
239
240 if (reserved_pebs > ubi->good_peb_count) {
241 ubi_err(ubi, "too large reserved_pebs %d, good PEBs %d",
242 reserved_pebs, ubi->good_peb_count);
243 err = 9;
244 goto bad;
245 }
246
247 if (name_len > UBI_VOL_NAME_MAX) {
248 err = 10;
249 goto bad;
250 }
251
252 if (name[0] == '\0') {
253 err = 11;
254 goto bad;
255 }
256
257 if (name_len != strnlen(name, name_len + 1)) {
258 err = 12;
259 goto bad;
260 }
261 }
262
263 /* Checks that all names are unique */
264 for (i = 0; i < ubi->vtbl_slots - 1; i++) {
265 for (n = i + 1; n < ubi->vtbl_slots; n++) {
266 int len1 = be16_to_cpu(vtbl[i].name_len);
267 int len2 = be16_to_cpu(vtbl[n].name_len);
268
269 if (len1 > 0 && len1 == len2 &&
270 !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
271 ubi_err(ubi, "volumes %d and %d have the same name \"%s\"",
272 i, n, vtbl[i].name);
273 ubi_dump_vtbl_record(&vtbl[i], i);
274 ubi_dump_vtbl_record(&vtbl[n], n);
275 return -EINVAL;
276 }
277 }
278 }
279
280 return 0;
281
282 bad:
283 ubi_err(ubi, "volume table check failed: record %d, error %d", i, err);
284 ubi_dump_vtbl_record(&vtbl[i], i);
285 return -EINVAL;
286 }
287
288 /**
289 * create_vtbl - create a copy of volume table.
290 * @ubi: UBI device description object
291 * @ai: attaching information
292 * @copy: number of the volume table copy
293 * @vtbl: contents of the volume table
294 *
295 * This function returns zero in case of success and a negative error code in
296 * case of failure.
297 */
create_vtbl(struct ubi_device * ubi,struct ubi_attach_info * ai,int copy,void * vtbl)298 static int create_vtbl(struct ubi_device *ubi, struct ubi_attach_info *ai,
299 int copy, void *vtbl)
300 {
301 int err, tries = 0;
302 struct ubi_vid_io_buf *vidb;
303 struct ubi_vid_hdr *vid_hdr;
304 struct ubi_ainf_peb *new_aeb;
305
306 dbg_gen("create volume table (copy #%d)", copy + 1);
307
308 vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
309 if (!vidb)
310 return -ENOMEM;
311
312 vid_hdr = ubi_get_vid_hdr(vidb);
313
314 retry:
315 new_aeb = ubi_early_get_peb(ubi, ai);
316 if (IS_ERR(new_aeb)) {
317 err = PTR_ERR(new_aeb);
318 goto out_free;
319 }
320
321 vid_hdr->vol_type = UBI_LAYOUT_VOLUME_TYPE;
322 vid_hdr->vol_id = cpu_to_be32(UBI_LAYOUT_VOLUME_ID);
323 vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT;
324 vid_hdr->data_size = vid_hdr->used_ebs =
325 vid_hdr->data_pad = cpu_to_be32(0);
326 vid_hdr->lnum = cpu_to_be32(copy);
327 vid_hdr->sqnum = cpu_to_be64(++ai->max_sqnum);
328
329 /* The EC header is already there, write the VID header */
330 err = ubi_io_write_vid_hdr(ubi, new_aeb->pnum, vidb);
331 if (err)
332 goto write_error;
333
334 /* Write the layout volume contents */
335 err = ubi_io_write_data(ubi, vtbl, new_aeb->pnum, 0, ubi->vtbl_size);
336 if (err)
337 goto write_error;
338
339 /*
340 * And add it to the attaching information. Don't delete the old version
341 * of this LEB as it will be deleted and freed in 'ubi_add_to_av()'.
342 */
343 err = ubi_add_to_av(ubi, ai, new_aeb->pnum, new_aeb->ec, vid_hdr, 0);
344 ubi_free_aeb(ai, new_aeb);
345 ubi_free_vid_buf(vidb);
346 return err;
347
348 write_error:
349 if (err == -EIO && ++tries <= 5) {
350 /*
351 * Probably this physical eraseblock went bad, try to pick
352 * another one.
353 */
354 list_add(&new_aeb->u.list, &ai->erase);
355 goto retry;
356 }
357 ubi_free_aeb(ai, new_aeb);
358 out_free:
359 ubi_free_vid_buf(vidb);
360 return err;
361
362 }
363
364 /**
365 * process_lvol - process the layout volume.
366 * @ubi: UBI device description object
367 * @ai: attaching information
368 * @av: layout volume attaching information
369 *
370 * This function is responsible for reading the layout volume, ensuring it is
371 * not corrupted, and recovering from corruptions if needed. Returns volume
372 * table in case of success and a negative error code in case of failure.
373 */
process_lvol(struct ubi_device * ubi,struct ubi_attach_info * ai,struct ubi_ainf_volume * av)374 static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
375 struct ubi_attach_info *ai,
376 struct ubi_ainf_volume *av)
377 {
378 int err;
379 struct rb_node *rb;
380 struct ubi_ainf_peb *aeb;
381 struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL };
382 int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1};
383
384 /*
385 * UBI goes through the following steps when it changes the layout
386 * volume:
387 * a. erase LEB 0;
388 * b. write new data to LEB 0;
389 * c. erase LEB 1;
390 * d. write new data to LEB 1.
391 *
392 * Before the change, both LEBs contain the same data.
393 *
394 * Due to unclean reboots, the contents of LEB 0 may be lost, but there
395 * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not.
396 * Similarly, LEB 1 may be lost, but there should be LEB 0. And
397 * finally, unclean reboots may result in a situation when neither LEB
398 * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB
399 * 0 contains more recent information.
400 *
401 * So the plan is to first check LEB 0. Then
402 * a. if LEB 0 is OK, it must be containing the most recent data; then
403 * we compare it with LEB 1, and if they are different, we copy LEB
404 * 0 to LEB 1;
405 * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1
406 * to LEB 0.
407 */
408
409 dbg_gen("check layout volume");
410
411 /* Read both LEB 0 and LEB 1 into memory */
412 ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
413 leb[aeb->lnum] = vzalloc(ubi->vtbl_size);
414 if (!leb[aeb->lnum]) {
415 err = -ENOMEM;
416 goto out_free;
417 }
418
419 err = ubi_io_read_data(ubi, leb[aeb->lnum], aeb->pnum, 0,
420 ubi->vtbl_size);
421 if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err))
422 /*
423 * Scrub the PEB later. Note, -EBADMSG indicates an
424 * uncorrectable ECC error, but we have our own CRC and
425 * the data will be checked later. If the data is OK,
426 * the PEB will be scrubbed (because we set
427 * aeb->scrub). If the data is not OK, the contents of
428 * the PEB will be recovered from the second copy, and
429 * aeb->scrub will be cleared in
430 * 'ubi_add_to_av()'.
431 */
432 aeb->scrub = 1;
433 else if (err)
434 goto out_free;
435 }
436
437 err = -EINVAL;
438 if (leb[0]) {
439 leb_corrupted[0] = vtbl_check(ubi, leb[0]);
440 if (leb_corrupted[0] < 0)
441 goto out_free;
442 }
443
444 if (!leb_corrupted[0]) {
445 /* LEB 0 is OK */
446 if (leb[1])
447 leb_corrupted[1] = memcmp(leb[0], leb[1],
448 ubi->vtbl_size);
449 if (leb_corrupted[1]) {
450 ubi_warn(ubi, "volume table copy #2 is corrupted");
451 err = create_vtbl(ubi, ai, 1, leb[0]);
452 if (err)
453 goto out_free;
454 ubi_msg(ubi, "volume table was restored");
455 }
456
457 /* Both LEB 1 and LEB 2 are OK and consistent */
458 vfree(leb[1]);
459 return leb[0];
460 } else {
461 /* LEB 0 is corrupted or does not exist */
462 if (leb[1]) {
463 leb_corrupted[1] = vtbl_check(ubi, leb[1]);
464 if (leb_corrupted[1] < 0)
465 goto out_free;
466 }
467 if (leb_corrupted[1]) {
468 /* Both LEB 0 and LEB 1 are corrupted */
469 ubi_err(ubi, "both volume tables are corrupted");
470 goto out_free;
471 }
472
473 ubi_warn(ubi, "volume table copy #1 is corrupted");
474 err = create_vtbl(ubi, ai, 0, leb[1]);
475 if (err)
476 goto out_free;
477 ubi_msg(ubi, "volume table was restored");
478
479 vfree(leb[0]);
480 return leb[1];
481 }
482
483 out_free:
484 vfree(leb[0]);
485 vfree(leb[1]);
486 return ERR_PTR(err);
487 }
488
489 /**
490 * create_empty_lvol - create empty layout volume.
491 * @ubi: UBI device description object
492 * @ai: attaching information
493 *
494 * This function returns volume table contents in case of success and a
495 * negative error code in case of failure.
496 */
create_empty_lvol(struct ubi_device * ubi,struct ubi_attach_info * ai)497 static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
498 struct ubi_attach_info *ai)
499 {
500 int i;
501 struct ubi_vtbl_record *vtbl;
502
503 vtbl = vzalloc(ubi->vtbl_size);
504 if (!vtbl)
505 return ERR_PTR(-ENOMEM);
506
507 for (i = 0; i < ubi->vtbl_slots; i++)
508 memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);
509
510 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
511 int err;
512
513 err = create_vtbl(ubi, ai, i, vtbl);
514 if (err) {
515 vfree(vtbl);
516 return ERR_PTR(err);
517 }
518 }
519
520 return vtbl;
521 }
522
523 /**
524 * init_volumes - initialize volume information for existing volumes.
525 * @ubi: UBI device description object
526 * @ai: scanning information
527 * @vtbl: volume table
528 *
529 * This function allocates volume description objects for existing volumes.
530 * Returns zero in case of success and a negative error code in case of
531 * failure.
532 */
init_volumes(struct ubi_device * ubi,const struct ubi_attach_info * ai,const struct ubi_vtbl_record * vtbl)533 static int init_volumes(struct ubi_device *ubi,
534 const struct ubi_attach_info *ai,
535 const struct ubi_vtbl_record *vtbl)
536 {
537 int i, err, reserved_pebs = 0;
538 struct ubi_ainf_volume *av;
539 struct ubi_volume *vol;
540
541 for (i = 0; i < ubi->vtbl_slots; i++) {
542 cond_resched();
543
544 if (be32_to_cpu(vtbl[i].reserved_pebs) == 0)
545 continue; /* Empty record */
546
547 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
548 if (!vol)
549 return -ENOMEM;
550
551 vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
552 vol->alignment = be32_to_cpu(vtbl[i].alignment);
553 vol->data_pad = be32_to_cpu(vtbl[i].data_pad);
554 vol->upd_marker = vtbl[i].upd_marker;
555 vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
556 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
557 vol->name_len = be16_to_cpu(vtbl[i].name_len);
558 vol->usable_leb_size = ubi->leb_size - vol->data_pad;
559 memcpy(vol->name, vtbl[i].name, vol->name_len);
560 vol->name[vol->name_len] = '\0';
561 vol->vol_id = i;
562
563 if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
564 /* Auto re-size flag may be set only for one volume */
565 if (ubi->autoresize_vol_id != -1) {
566 ubi_err(ubi, "more than one auto-resize volume (%d and %d)",
567 ubi->autoresize_vol_id, i);
568 kfree(vol);
569 return -EINVAL;
570 }
571
572 ubi->autoresize_vol_id = i;
573 }
574
575 ubi_assert(!ubi->volumes[i]);
576 ubi->volumes[i] = vol;
577 ubi->vol_count += 1;
578 vol->ubi = ubi;
579 reserved_pebs += vol->reserved_pebs;
580
581 /*
582 * We use ubi->peb_count and not vol->reserved_pebs because
583 * we want to keep the code simple. Otherwise we'd have to
584 * resize/check the bitmap upon volume resize too.
585 * Allocating a few bytes more does not hurt.
586 */
587 err = ubi_fastmap_init_checkmap(vol, ubi->peb_count);
588 if (err)
589 return err;
590
591 /*
592 * In case of dynamic volume UBI knows nothing about how many
593 * data is stored there. So assume the whole volume is used.
594 */
595 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
596 vol->used_ebs = vol->reserved_pebs;
597 vol->last_eb_bytes = vol->usable_leb_size;
598 vol->used_bytes =
599 (long long)vol->used_ebs * vol->usable_leb_size;
600 continue;
601 }
602
603 /* Static volumes only */
604 av = ubi_find_av(ai, i);
605 if (!av || !av->leb_count) {
606 /*
607 * No eraseblocks belonging to this volume found. We
608 * don't actually know whether this static volume is
609 * completely corrupted or just contains no data. And
610 * we cannot know this as long as data size is not
611 * stored on flash. So we just assume the volume is
612 * empty. FIXME: this should be handled.
613 */
614 continue;
615 }
616
617 if (av->leb_count != av->used_ebs) {
618 /*
619 * We found a static volume which misses several
620 * eraseblocks. Treat it as corrupted.
621 */
622 ubi_warn(ubi, "static volume %d misses %d LEBs - corrupted",
623 av->vol_id, av->used_ebs - av->leb_count);
624 vol->corrupted = 1;
625 continue;
626 }
627
628 vol->used_ebs = av->used_ebs;
629 vol->used_bytes =
630 (long long)(vol->used_ebs - 1) * vol->usable_leb_size;
631 vol->used_bytes += av->last_data_size;
632 vol->last_eb_bytes = av->last_data_size;
633 }
634
635 /* And add the layout volume */
636 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
637 if (!vol)
638 return -ENOMEM;
639
640 vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
641 vol->alignment = UBI_LAYOUT_VOLUME_ALIGN;
642 vol->vol_type = UBI_DYNAMIC_VOLUME;
643 vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
644 memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
645 vol->usable_leb_size = ubi->leb_size;
646 vol->used_ebs = vol->reserved_pebs;
647 vol->last_eb_bytes = vol->reserved_pebs;
648 vol->used_bytes =
649 (long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
650 vol->vol_id = UBI_LAYOUT_VOLUME_ID;
651 vol->ref_count = 1;
652
653 ubi_assert(!ubi->volumes[i]);
654 ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
655 reserved_pebs += vol->reserved_pebs;
656 ubi->vol_count += 1;
657 vol->ubi = ubi;
658 err = ubi_fastmap_init_checkmap(vol, UBI_LAYOUT_VOLUME_EBS);
659 if (err)
660 return err;
661
662 if (reserved_pebs > ubi->avail_pebs) {
663 ubi_err(ubi, "not enough PEBs, required %d, available %d",
664 reserved_pebs, ubi->avail_pebs);
665 if (ubi->corr_peb_count)
666 ubi_err(ubi, "%d PEBs are corrupted and not used",
667 ubi->corr_peb_count);
668 return -ENOSPC;
669 }
670 ubi->rsvd_pebs += reserved_pebs;
671 ubi->avail_pebs -= reserved_pebs;
672
673 return 0;
674 }
675
676 /**
677 * check_av - check volume attaching information.
678 * @vol: UBI volume description object
679 * @av: volume attaching information
680 *
681 * This function returns zero if the volume attaching information is consistent
682 * to the data read from the volume tabla, and %-EINVAL if not.
683 */
check_av(const struct ubi_volume * vol,const struct ubi_ainf_volume * av)684 static int check_av(const struct ubi_volume *vol,
685 const struct ubi_ainf_volume *av)
686 {
687 int err;
688
689 if (av->highest_lnum >= vol->reserved_pebs) {
690 err = 1;
691 goto bad;
692 }
693 if (av->leb_count > vol->reserved_pebs) {
694 err = 2;
695 goto bad;
696 }
697 if (av->vol_type != vol->vol_type) {
698 err = 3;
699 goto bad;
700 }
701 if (av->used_ebs > vol->reserved_pebs) {
702 err = 4;
703 goto bad;
704 }
705 if (av->data_pad != vol->data_pad) {
706 err = 5;
707 goto bad;
708 }
709 return 0;
710
711 bad:
712 ubi_err(vol->ubi, "bad attaching information, error %d", err);
713 ubi_dump_av(av);
714 ubi_dump_vol_info(vol);
715 return -EINVAL;
716 }
717
718 /**
719 * check_attaching_info - check that attaching information.
720 * @ubi: UBI device description object
721 * @ai: attaching information
722 *
723 * Even though we protect on-flash data by CRC checksums, we still don't trust
724 * the media. This function ensures that attaching information is consistent to
725 * the information read from the volume table. Returns zero if the attaching
726 * information is OK and %-EINVAL if it is not.
727 */
check_attaching_info(const struct ubi_device * ubi,struct ubi_attach_info * ai)728 static int check_attaching_info(const struct ubi_device *ubi,
729 struct ubi_attach_info *ai)
730 {
731 int err, i;
732 struct ubi_ainf_volume *av;
733 struct ubi_volume *vol;
734
735 if (ai->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
736 ubi_err(ubi, "found %d volumes while attaching, maximum is %d + %d",
737 ai->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
738 return -EINVAL;
739 }
740
741 if (ai->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT &&
742 ai->highest_vol_id < UBI_INTERNAL_VOL_START) {
743 ubi_err(ubi, "too large volume ID %d found",
744 ai->highest_vol_id);
745 return -EINVAL;
746 }
747
748 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
749 cond_resched();
750
751 av = ubi_find_av(ai, i);
752 vol = ubi->volumes[i];
753 if (!vol) {
754 if (av)
755 ubi_remove_av(ai, av);
756 continue;
757 }
758
759 if (vol->reserved_pebs == 0) {
760 ubi_assert(i < ubi->vtbl_slots);
761
762 if (!av)
763 continue;
764
765 /*
766 * During attaching we found a volume which does not
767 * exist according to the information in the volume
768 * table. This must have happened due to an unclean
769 * reboot while the volume was being removed. Discard
770 * these eraseblocks.
771 */
772 ubi_msg(ubi, "finish volume %d removal", av->vol_id);
773 ubi_remove_av(ai, av);
774 } else if (av) {
775 err = check_av(vol, av);
776 if (err)
777 return err;
778 }
779 }
780
781 return 0;
782 }
783
784 /**
785 * ubi_read_volume_table - read the volume table.
786 * @ubi: UBI device description object
787 * @ai: attaching information
788 *
789 * This function reads volume table, checks it, recover from errors if needed,
790 * or creates it if needed. Returns zero in case of success and a negative
791 * error code in case of failure.
792 */
ubi_read_volume_table(struct ubi_device * ubi,struct ubi_attach_info * ai)793 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_attach_info *ai)
794 {
795 int i, err;
796 struct ubi_ainf_volume *av;
797
798 empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
799
800 /*
801 * The number of supported volumes is limited by the eraseblock size
802 * and by the UBI_MAX_VOLUMES constant.
803 */
804 ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
805 if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
806 ubi->vtbl_slots = UBI_MAX_VOLUMES;
807
808 ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
809 ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);
810
811 av = ubi_find_av(ai, UBI_LAYOUT_VOLUME_ID);
812 if (!av) {
813 /*
814 * No logical eraseblocks belonging to the layout volume were
815 * found. This could mean that the flash is just empty. In
816 * this case we create empty layout volume.
817 *
818 * But if flash is not empty this must be a corruption or the
819 * MTD device just contains garbage.
820 */
821 if (ai->is_empty) {
822 ubi->vtbl = create_empty_lvol(ubi, ai);
823 if (IS_ERR(ubi->vtbl))
824 return PTR_ERR(ubi->vtbl);
825 } else {
826 ubi_err(ubi, "the layout volume was not found");
827 return -EINVAL;
828 }
829 } else {
830 if (av->leb_count > UBI_LAYOUT_VOLUME_EBS) {
831 /* This must not happen with proper UBI images */
832 ubi_err(ubi, "too many LEBs (%d) in layout volume",
833 av->leb_count);
834 return -EINVAL;
835 }
836
837 ubi->vtbl = process_lvol(ubi, ai, av);
838 if (IS_ERR(ubi->vtbl))
839 return PTR_ERR(ubi->vtbl);
840 }
841
842 ubi->avail_pebs = ubi->good_peb_count - ubi->corr_peb_count;
843
844 /*
845 * The layout volume is OK, initialize the corresponding in-RAM data
846 * structures.
847 */
848 err = init_volumes(ubi, ai, ubi->vtbl);
849 if (err)
850 goto out_free;
851
852 /*
853 * Make sure that the attaching information is consistent to the
854 * information stored in the volume table.
855 */
856 err = check_attaching_info(ubi, ai);
857 if (err)
858 goto out_free;
859
860 return 0;
861
862 out_free:
863 vfree(ubi->vtbl);
864 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
865 ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
866 kfree(ubi->volumes[i]);
867 ubi->volumes[i] = NULL;
868 }
869 return err;
870 }
871
872 /**
873 * self_vtbl_check - check volume table.
874 * @ubi: UBI device description object
875 */
self_vtbl_check(const struct ubi_device * ubi)876 static void self_vtbl_check(const struct ubi_device *ubi)
877 {
878 if (!ubi_dbg_chk_gen(ubi))
879 return;
880
881 if (vtbl_check(ubi, ubi->vtbl)) {
882 ubi_err(ubi, "self-check failed");
883 BUG();
884 }
885 }
886