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 (���������������� ����������) 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. 34 * 35 * The volume table is changed, it is first changed in RAM. Then LEB 0 is 36 * erased, and the updated volume table is written back to LEB 0. Then same for 37 * LEB 1. This scheme guarantees recoverability from unclean reboots. 38 * 39 * In this UBI implementation the on-flash volume table does not contain any 40 * information about how many data static volumes contain. This information may 41 * be found from the scanning data. 42 * 43 * But it would still be beneficial to store this information in the volume 44 * table. For example, suppose we have a static volume X, and all its physical 45 * eraseblocks became bad for some reasons. Suppose we are attaching the 46 * corresponding MTD device, the scanning has found no logical eraseblocks 47 * corresponding to the volume X. According to the volume table volume X does 48 * exist. So we don't know whether it is just empty or all its physical 49 * eraseblocks went bad. So we cannot alarm the user about this corruption. 50 * 51 * The volume table also stores so-called "update marker", which is used for 52 * volume updates. Before updating the volume, the update marker is set, and 53 * after the update operation is finished, the update marker is cleared. So if 54 * the update operation was interrupted (e.g. by an unclean reboot) - the 55 * update marker is still there and we know that the volume's contents is 56 * damaged. 57 */ 58 59#include <linux/crc32.h> 60#include <linux/err.h> 61#include <linux/slab.h> 62#include <asm/div64.h> 63#include "ubi.h" 64 65#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID 66static void paranoid_vtbl_check(const struct ubi_device *ubi); 67#else 68#define paranoid_vtbl_check(ubi) 69#endif 70 71/* Empty volume table record */ 72static struct ubi_vtbl_record empty_vtbl_record; 73 74/** 75 * ubi_change_vtbl_record - change volume table record. 76 * @ubi: UBI device description object 77 * @idx: table index to change 78 * @vtbl_rec: new volume table record 79 * 80 * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty 81 * volume table record is written. The caller does not have to calculate CRC of 82 * the record as it is done by this function. Returns zero in case of success 83 * and a negative error code in case of failure. 84 */ 85int ubi_change_vtbl_record(struct ubi_device *ubi, int idx, 86 struct ubi_vtbl_record *vtbl_rec) 87{ 88 int i, err; 89 uint32_t crc; 90 struct ubi_volume *layout_vol; 91 92 ubi_assert(idx >= 0 && idx < ubi->vtbl_slots); 93 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)]; 94 95 if (!vtbl_rec) 96 vtbl_rec = &empty_vtbl_record; 97 else { 98 crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC); 99 vtbl_rec->crc = cpu_to_be32(crc); 100 } 101 102 memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record)); 103 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) { 104 err = ubi_eba_unmap_leb(ubi, layout_vol, i); 105 if (err) 106 return err; 107 108 err = ubi_eba_write_leb(ubi, layout_vol, i, ubi->vtbl, 0, 109 ubi->vtbl_size, UBI_LONGTERM); 110 if (err) 111 return err; 112 } 113 114 paranoid_vtbl_check(ubi); 115 return 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 */ 127int ubi_vtbl_rename_volumes(struct ubi_device *ubi, 128 struct list_head *rename_list) 129{ 130 int i, err; 131 struct ubi_rename_entry *re; 132 struct ubi_volume *layout_vol; 133 134 list_for_each_entry(re, rename_list, list) { 135 uint32_t crc; 136 struct ubi_volume *vol = re->desc->vol; 137 struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol->vol_id]; 138 139 if (re->remove) { 140 memcpy(vtbl_rec, &empty_vtbl_record, 141 sizeof(struct ubi_vtbl_record)); 142 continue; 143 } 144 145 vtbl_rec->name_len = cpu_to_be16(re->new_name_len); 146 memcpy(vtbl_rec->name, re->new_name, re->new_name_len); 147 memset(vtbl_rec->name + re->new_name_len, 0, 148 UBI_VOL_NAME_MAX + 1 - re->new_name_len); 149 crc = crc32(UBI_CRC32_INIT, vtbl_rec, 150 UBI_VTBL_RECORD_SIZE_CRC); 151 vtbl_rec->crc = cpu_to_be32(crc); 152 } 153 154 layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)]; 155 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) { 156 err = ubi_eba_unmap_leb(ubi, layout_vol, i); 157 if (err) 158 return err; 159 160 err = ubi_eba_write_leb(ubi, layout_vol, i, ubi->vtbl, 0, 161 ubi->vtbl_size, UBI_LONGTERM); 162 if (err) 163 return err; 164 } 165 166 return 0; 167} 168 169/** 170 * vtbl_check - check if volume table is not corrupted and sensible. 171 * @ubi: UBI device description object 172 * @vtbl: volume table 173 * 174 * This function returns zero if @vtbl is all right, %1 if CRC is incorrect, 175 * and %-EINVAL if it contains inconsistent data. 176 */ 177static int vtbl_check(const struct ubi_device *ubi, 178 const struct ubi_vtbl_record *vtbl) 179{ 180 int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len; 181 int upd_marker, err; 182 uint32_t crc; 183 const char *name; 184 185 for (i = 0; i < ubi->vtbl_slots; i++) { 186 cond_resched(); 187 188 reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs); 189 alignment = be32_to_cpu(vtbl[i].alignment); 190 data_pad = be32_to_cpu(vtbl[i].data_pad); 191 upd_marker = vtbl[i].upd_marker; 192 vol_type = vtbl[i].vol_type; 193 name_len = be16_to_cpu(vtbl[i].name_len); 194 name = &vtbl[i].name[0]; 195 196 crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC); 197 if (be32_to_cpu(vtbl[i].crc) != crc) { 198 ubi_err("bad CRC at record %u: %#08x, not %#08x", 199 i, crc, be32_to_cpu(vtbl[i].crc)); 200 ubi_dbg_dump_vtbl_record(&vtbl[i], i); 201 return 1; 202 } 203 204 if (reserved_pebs == 0) { 205 if (memcmp(&vtbl[i], &empty_vtbl_record, 206 UBI_VTBL_RECORD_SIZE)) { 207 err = 2; 208 goto bad; 209 } 210 continue; 211 } 212 213 if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 || 214 name_len < 0) { 215 err = 3; 216 goto bad; 217 } 218 219 if (alignment > ubi->leb_size || alignment == 0) { 220 err = 4; 221 goto bad; 222 } 223 224 n = alignment & (ubi->min_io_size - 1); 225 if (alignment != 1 && n) { 226 err = 5; 227 goto bad; 228 } 229 230 n = ubi->leb_size % alignment; 231 if (data_pad != n) { 232 dbg_err("bad data_pad, has to be %d", n); 233 err = 6; 234 goto bad; 235 } 236 237 if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) { 238 err = 7; 239 goto bad; 240 } 241 242 if (upd_marker != 0 && upd_marker != 1) { 243 err = 8; 244 goto bad; 245 } 246 247 if (reserved_pebs > ubi->good_peb_count) { 248 dbg_err("too large reserved_pebs %d, good PEBs %d", 249 reserved_pebs, ubi->good_peb_count); 250 err = 9; 251 goto bad; 252 } 253 254 if (name_len > UBI_VOL_NAME_MAX) { 255 err = 10; 256 goto bad; 257 } 258 259 if (name[0] == '\0') { 260 err = 11; 261 goto bad; 262 } 263 264 if (name_len != strnlen(name, name_len + 1)) { 265 err = 12; 266 goto bad; 267 } 268 } 269 270 /* Checks that all names are unique */ 271 for (i = 0; i < ubi->vtbl_slots - 1; i++) { 272 for (n = i + 1; n < ubi->vtbl_slots; n++) { 273 int len1 = be16_to_cpu(vtbl[i].name_len); 274 int len2 = be16_to_cpu(vtbl[n].name_len); 275 276 if (len1 > 0 && len1 == len2 && 277 !strncmp(vtbl[i].name, vtbl[n].name, len1)) { 278 ubi_err("volumes %d and %d have the same name" 279 " \"%s\"", i, n, vtbl[i].name); 280 ubi_dbg_dump_vtbl_record(&vtbl[i], i); 281 ubi_dbg_dump_vtbl_record(&vtbl[n], n); 282 return -EINVAL; 283 } 284 } 285 } 286 287 return 0; 288 289bad: 290 ubi_err("volume table check failed: record %d, error %d", i, err); 291 ubi_dbg_dump_vtbl_record(&vtbl[i], i); 292 return -EINVAL; 293} 294 295/** 296 * create_vtbl - create a copy of volume table. 297 * @ubi: UBI device description object 298 * @si: scanning information 299 * @copy: number of the volume table copy 300 * @vtbl: contents of the volume table 301 * 302 * This function returns zero in case of success and a negative error code in 303 * case of failure. 304 */ 305static int create_vtbl(struct ubi_device *ubi, struct ubi_scan_info *si, 306 int copy, void *vtbl) 307{ 308 int err, tries = 0; 309 static struct ubi_vid_hdr *vid_hdr; 310 struct ubi_scan_volume *sv; 311 struct ubi_scan_leb *new_seb, *old_seb = NULL; 312 313 ubi_msg("create volume table (copy #%d)", copy + 1); 314 315 vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL); 316 if (!vid_hdr) 317 return -ENOMEM; 318 319 /* 320 * Check if there is a logical eraseblock which would have to contain 321 * this volume table copy was found during scanning. It has to be wiped 322 * out. 323 */ 324 sv = ubi_scan_find_sv(si, UBI_LAYOUT_VOLUME_ID); 325 if (sv) 326 old_seb = ubi_scan_find_seb(sv, copy); 327 328retry: 329 new_seb = ubi_scan_get_free_peb(ubi, si); 330 if (IS_ERR(new_seb)) { 331 err = PTR_ERR(new_seb); 332 goto out_free; 333 } 334 335 vid_hdr->vol_type = UBI_VID_DYNAMIC; 336 vid_hdr->vol_id = cpu_to_be32(UBI_LAYOUT_VOLUME_ID); 337 vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT; 338 vid_hdr->data_size = vid_hdr->used_ebs = 339 vid_hdr->data_pad = cpu_to_be32(0); 340 vid_hdr->lnum = cpu_to_be32(copy); 341 vid_hdr->sqnum = cpu_to_be64(++si->max_sqnum); 342 343 /* The EC header is already there, write the VID header */ 344 err = ubi_io_write_vid_hdr(ubi, new_seb->pnum, vid_hdr); 345 if (err) 346 goto write_error; 347 348 /* Write the layout volume contents */ 349 err = ubi_io_write_data(ubi, vtbl, new_seb->pnum, 0, ubi->vtbl_size); 350 if (err) 351 goto write_error; 352 353 /* 354 * And add it to the scanning information. Don't delete the old 355 * @old_seb as it will be deleted and freed in 'ubi_scan_add_used()'. 356 */ 357 err = ubi_scan_add_used(ubi, si, new_seb->pnum, new_seb->ec, 358 vid_hdr, 0); 359 kfree(new_seb); 360 ubi_free_vid_hdr(ubi, vid_hdr); 361 return err; 362 363write_error: 364 if (err == -EIO && ++tries <= 5) { 365 /* 366 * Probably this physical eraseblock went bad, try to pick 367 * another one. 368 */ 369 list_add_tail(&new_seb->u.list, &si->corr); 370 goto retry; 371 } 372 kfree(new_seb); 373out_free: 374 ubi_free_vid_hdr(ubi, vid_hdr); 375 return err; 376 377} 378 379/** 380 * process_lvol - process the layout volume. 381 * @ubi: UBI device description object 382 * @si: scanning information 383 * @sv: layout volume scanning information 384 * 385 * This function is responsible for reading the layout volume, ensuring it is 386 * not corrupted, and recovering from corruptions if needed. Returns volume 387 * table in case of success and a negative error code in case of failure. 388 */ 389static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi, 390 struct ubi_scan_info *si, 391 struct ubi_scan_volume *sv) 392{ 393 int err; 394 struct rb_node *rb; 395 struct ubi_scan_leb *seb; 396 struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL }; 397 int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1}; 398 399 /* 400 * UBI goes through the following steps when it changes the layout 401 * volume: 402 * a. erase LEB 0; 403 * b. write new data to LEB 0; 404 * c. erase LEB 1; 405 * d. write new data to LEB 1. 406 * 407 * Before the change, both LEBs contain the same data. 408 * 409 * Due to unclean reboots, the contents of LEB 0 may be lost, but there 410 * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not. 411 * Similarly, LEB 1 may be lost, but there should be LEB 0. And 412 * finally, unclean reboots may result in a situation when neither LEB 413 * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB 414 * 0 contains more recent information. 415 * 416 * So the plan is to first check LEB 0. Then 417 * a. if LEB 0 is OK, it must be containing the most recent data; then 418 * we compare it with LEB 1, and if they are different, we copy LEB 419 * 0 to LEB 1; 420 * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1 421 * to LEB 0. 422 */ 423 424 dbg_gen("check layout volume"); 425 426 /* Read both LEB 0 and LEB 1 into memory */ 427 ubi_rb_for_each_entry(rb, seb, &sv->root, u.rb) { 428 leb[seb->lnum] = vmalloc(ubi->vtbl_size); 429 if (!leb[seb->lnum]) { 430 err = -ENOMEM; 431 goto out_free; 432 } 433 memset(leb[seb->lnum], 0, ubi->vtbl_size); 434 435 err = ubi_io_read_data(ubi, leb[seb->lnum], seb->pnum, 0, 436 ubi->vtbl_size); 437 if (err == UBI_IO_BITFLIPS || err == -EBADMSG) 438 /* 439 * Scrub the PEB later. Note, -EBADMSG indicates an 440 * uncorrectable ECC error, but we have our own CRC and 441 * the data will be checked later. If the data is OK, 442 * the PEB will be scrubbed (because we set 443 * seb->scrub). If the data is not OK, the contents of 444 * the PEB will be recovered from the second copy, and 445 * seb->scrub will be cleared in 446 * 'ubi_scan_add_used()'. 447 */ 448 seb->scrub = 1; 449 else if (err) 450 goto out_free; 451 } 452 453 err = -EINVAL; 454 if (leb[0]) { 455 leb_corrupted[0] = vtbl_check(ubi, leb[0]); 456 if (leb_corrupted[0] < 0) 457 goto out_free; 458 } 459 460 if (!leb_corrupted[0]) { 461 /* LEB 0 is OK */ 462 if (leb[1]) 463 leb_corrupted[1] = memcmp(leb[0], leb[1], 464 ubi->vtbl_size); 465 if (leb_corrupted[1]) { 466 ubi_warn("volume table copy #2 is corrupted"); 467 err = create_vtbl(ubi, si, 1, leb[0]); 468 if (err) 469 goto out_free; 470 ubi_msg("volume table was restored"); 471 } 472 473 /* Both LEB 1 and LEB 2 are OK and consistent */ 474 vfree(leb[1]); 475 return leb[0]; 476 } else { 477 /* LEB 0 is corrupted or does not exist */ 478 if (leb[1]) { 479 leb_corrupted[1] = vtbl_check(ubi, leb[1]); 480 if (leb_corrupted[1] < 0) 481 goto out_free; 482 } 483 if (leb_corrupted[1]) { 484 /* Both LEB 0 and LEB 1 are corrupted */ 485 ubi_err("both volume tables are corrupted"); 486 goto out_free; 487 } 488 489 ubi_warn("volume table copy #1 is corrupted"); 490 err = create_vtbl(ubi, si, 0, leb[1]); 491 if (err) 492 goto out_free; 493 ubi_msg("volume table was restored"); 494 495 vfree(leb[0]); 496 return leb[1]; 497 } 498 499out_free: 500 vfree(leb[0]); 501 vfree(leb[1]); 502 return ERR_PTR(err); 503} 504 505/** 506 * create_empty_lvol - create empty layout volume. 507 * @ubi: UBI device description object 508 * @si: scanning information 509 * 510 * This function returns volume table contents in case of success and a 511 * negative error code in case of failure. 512 */ 513static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi, 514 struct ubi_scan_info *si) 515{ 516 int i; 517 struct ubi_vtbl_record *vtbl; 518 519 vtbl = vmalloc(ubi->vtbl_size); 520 if (!vtbl) 521 return ERR_PTR(-ENOMEM); 522 memset(vtbl, 0, ubi->vtbl_size); 523 524 for (i = 0; i < ubi->vtbl_slots; i++) 525 memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE); 526 527 for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) { 528 int err; 529 530 err = create_vtbl(ubi, si, i, vtbl); 531 if (err) { 532 vfree(vtbl); 533 return ERR_PTR(err); 534 } 535 } 536 537 return vtbl; 538} 539 540/** 541 * init_volumes - initialize volume information for existing volumes. 542 * @ubi: UBI device description object 543 * @si: scanning information 544 * @vtbl: volume table 545 * 546 * This function allocates volume description objects for existing volumes. 547 * Returns zero in case of success and a negative error code in case of 548 * failure. 549 */ 550static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si, 551 const struct ubi_vtbl_record *vtbl) 552{ 553 int i, reserved_pebs = 0; 554 struct ubi_scan_volume *sv; 555 struct ubi_volume *vol; 556 557 for (i = 0; i < ubi->vtbl_slots; i++) { 558 cond_resched(); 559 560 if (be32_to_cpu(vtbl[i].reserved_pebs) == 0) 561 continue; /* Empty record */ 562 563 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL); 564 if (!vol) 565 return -ENOMEM; 566 567 vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs); 568 vol->alignment = be32_to_cpu(vtbl[i].alignment); 569 vol->data_pad = be32_to_cpu(vtbl[i].data_pad); 570 vol->upd_marker = vtbl[i].upd_marker; 571 vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ? 572 UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME; 573 vol->name_len = be16_to_cpu(vtbl[i].name_len); 574 vol->usable_leb_size = ubi->leb_size - vol->data_pad; 575 memcpy(vol->name, vtbl[i].name, vol->name_len); 576 vol->name[vol->name_len] = '\0'; 577 vol->vol_id = i; 578 579 if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) { 580 /* Auto re-size flag may be set only for one volume */ 581 if (ubi->autoresize_vol_id != -1) { 582 ubi_err("more than one auto-resize volume (%d " 583 "and %d)", ubi->autoresize_vol_id, i); 584 kfree(vol); 585 return -EINVAL; 586 } 587 588 ubi->autoresize_vol_id = i; 589 } 590 591 ubi_assert(!ubi->volumes[i]); 592 ubi->volumes[i] = vol; 593 ubi->vol_count += 1; 594 vol->ubi = ubi; 595 reserved_pebs += vol->reserved_pebs; 596 597 /* 598 * In case of dynamic volume UBI knows nothing about how many 599 * data is stored there. So assume the whole volume is used. 600 */ 601 if (vol->vol_type == UBI_DYNAMIC_VOLUME) { 602 vol->used_ebs = vol->reserved_pebs; 603 vol->last_eb_bytes = vol->usable_leb_size; 604 vol->used_bytes = 605 (long long)vol->used_ebs * vol->usable_leb_size; 606 continue; 607 } 608 609 /* Static volumes only */ 610 sv = ubi_scan_find_sv(si, i); 611 if (!sv) { 612 continue; 613 } 614 615 if (sv->leb_count != sv->used_ebs) { 616 /* 617 * We found a static volume which misses several 618 * eraseblocks. Treat it as corrupted. 619 */ 620 ubi_warn("static volume %d misses %d LEBs - corrupted", 621 sv->vol_id, sv->used_ebs - sv->leb_count); 622 vol->corrupted = 1; 623 continue; 624 } 625 626 vol->used_ebs = sv->used_ebs; 627 vol->used_bytes = 628 (long long)(vol->used_ebs - 1) * vol->usable_leb_size; 629 vol->used_bytes += sv->last_data_size; 630 vol->last_eb_bytes = sv->last_data_size; 631 } 632 633 /* And add the layout volume */ 634 vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL); 635 if (!vol) 636 return -ENOMEM; 637 638 vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS; 639 vol->alignment = 1; 640 vol->vol_type = UBI_DYNAMIC_VOLUME; 641 vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1; 642 memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1); 643 vol->usable_leb_size = ubi->leb_size; 644 vol->used_ebs = vol->reserved_pebs; 645 vol->last_eb_bytes = vol->reserved_pebs; 646 vol->used_bytes = 647 (long long)vol->used_ebs * (ubi->leb_size - vol->data_pad); 648 vol->vol_id = UBI_LAYOUT_VOLUME_ID; 649 vol->ref_count = 1; 650 651 ubi_assert(!ubi->volumes[i]); 652 ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol; 653 reserved_pebs += vol->reserved_pebs; 654 ubi->vol_count += 1; 655 vol->ubi = ubi; 656 657 if (reserved_pebs > ubi->avail_pebs) 658 ubi_err("not enough PEBs, required %d, available %d", 659 reserved_pebs, ubi->avail_pebs); 660 ubi->rsvd_pebs += reserved_pebs; 661 ubi->avail_pebs -= reserved_pebs; 662 663 return 0; 664} 665 666/** 667 * check_sv - check volume scanning information. 668 * @vol: UBI volume description object 669 * @sv: volume scanning information 670 * 671 * This function returns zero if the volume scanning information is consistent 672 * to the data read from the volume tabla, and %-EINVAL if not. 673 */ 674static int check_sv(const struct ubi_volume *vol, 675 const struct ubi_scan_volume *sv) 676{ 677 int err; 678 679 if (sv->highest_lnum >= vol->reserved_pebs) { 680 err = 1; 681 goto bad; 682 } 683 if (sv->leb_count > vol->reserved_pebs) { 684 err = 2; 685 goto bad; 686 } 687 if (sv->vol_type != vol->vol_type) { 688 err = 3; 689 goto bad; 690 } 691 if (sv->used_ebs > vol->reserved_pebs) { 692 err = 4; 693 goto bad; 694 } 695 if (sv->data_pad != vol->data_pad) { 696 err = 5; 697 goto bad; 698 } 699 return 0; 700 701bad: 702 ubi_err("bad scanning information, error %d", err); 703 ubi_dbg_dump_sv(sv); 704 ubi_dbg_dump_vol_info(vol); 705 return -EINVAL; 706} 707 708/** 709 * check_scanning_info - check that scanning information. 710 * @ubi: UBI device description object 711 * @si: scanning information 712 * 713 * Even though we protect on-flash data by CRC checksums, we still don't trust 714 * the media. This function ensures that scanning information is consistent to 715 * the information read from the volume table. Returns zero if the scanning 716 * information is OK and %-EINVAL if it is not. 717 */ 718static int check_scanning_info(const struct ubi_device *ubi, 719 struct ubi_scan_info *si) 720{ 721 int err, i; 722 struct ubi_scan_volume *sv; 723 struct ubi_volume *vol; 724 725 if (si->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) { 726 ubi_err("scanning found %d volumes, maximum is %d + %d", 727 si->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots); 728 return -EINVAL; 729 } 730 731 if (si->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT && 732 si->highest_vol_id < UBI_INTERNAL_VOL_START) { 733 ubi_err("too large volume ID %d found by scanning", 734 si->highest_vol_id); 735 return -EINVAL; 736 } 737 738 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) { 739 cond_resched(); 740 741 sv = ubi_scan_find_sv(si, i); 742 vol = ubi->volumes[i]; 743 if (!vol) { 744 if (sv) 745 ubi_scan_rm_volume(si, sv); 746 continue; 747 } 748 749 if (vol->reserved_pebs == 0) { 750 ubi_assert(i < ubi->vtbl_slots); 751 752 if (!sv) 753 continue; 754 755 /* 756 * During scanning we found a volume which does not 757 * exist according to the information in the volume 758 * table. This must have happened due to an unclean 759 * reboot while the volume was being removed. Discard 760 * these eraseblocks. 761 */ 762 ubi_msg("finish volume %d removal", sv->vol_id); 763 ubi_scan_rm_volume(si, sv); 764 } else if (sv) { 765 err = check_sv(vol, sv); 766 if (err) 767 return err; 768 } 769 } 770 771 return 0; 772} 773 774/** 775 * ubi_read_volume_table - read the volume table. 776 * @ubi: UBI device description object 777 * @si: scanning information 778 * 779 * This function reads volume table, checks it, recover from errors if needed, 780 * or creates it if needed. Returns zero in case of success and a negative 781 * error code in case of failure. 782 */ 783int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si) 784{ 785 int i, err; 786 struct ubi_scan_volume *sv; 787 788 empty_vtbl_record.crc = cpu_to_be32(0xf116c36b); 789 790 /* 791 * The number of supported volumes is limited by the eraseblock size 792 * and by the UBI_MAX_VOLUMES constant. 793 */ 794 ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE; 795 if (ubi->vtbl_slots > UBI_MAX_VOLUMES) 796 ubi->vtbl_slots = UBI_MAX_VOLUMES; 797 798 ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE; 799 ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size); 800 801 sv = ubi_scan_find_sv(si, UBI_LAYOUT_VOLUME_ID); 802 if (!sv) { 803 /* 804 * No logical eraseblocks belonging to the layout volume were 805 * found. This could mean that the flash is just empty. In 806 * this case we create empty layout volume. 807 * 808 * But if flash is not empty this must be a corruption or the 809 * MTD device just contains garbage. 810 */ 811 if (si->is_empty) { 812 ubi->vtbl = create_empty_lvol(ubi, si); 813 if (IS_ERR(ubi->vtbl)) 814 return PTR_ERR(ubi->vtbl); 815 } else { 816 ubi_err("the layout volume was not found"); 817 return -EINVAL; 818 } 819 } else { 820 if (sv->leb_count > UBI_LAYOUT_VOLUME_EBS) { 821 /* This must not happen with proper UBI images */ 822 dbg_err("too many LEBs (%d) in layout volume", 823 sv->leb_count); 824 return -EINVAL; 825 } 826 827 ubi->vtbl = process_lvol(ubi, si, sv); 828 if (IS_ERR(ubi->vtbl)) 829 return PTR_ERR(ubi->vtbl); 830 } 831 832 ubi->avail_pebs = ubi->good_peb_count; 833 834 /* 835 * The layout volume is OK, initialize the corresponding in-RAM data 836 * structures. 837 */ 838 err = init_volumes(ubi, si, ubi->vtbl); 839 if (err) 840 goto out_free; 841 842 /* 843 * Make sure that the scanning information is consistent to the 844 * information stored in the volume table. 845 */ 846 err = check_scanning_info(ubi, si); 847 if (err) 848 goto out_free; 849 850 return 0; 851 852out_free: 853 vfree(ubi->vtbl); 854 for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) { 855 kfree(ubi->volumes[i]); 856 ubi->volumes[i] = NULL; 857 } 858 return err; 859} 860 861#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID 862 863/** 864 * paranoid_vtbl_check - check volume table. 865 * @ubi: UBI device description object 866 */ 867static void paranoid_vtbl_check(const struct ubi_device *ubi) 868{ 869 if (vtbl_check(ubi, ubi->vtbl)) { 870 ubi_err("paranoid check failed"); 871 BUG(); 872 } 873} 874 875#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */ 876