drivers/mtd/ubi/scan.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  *
   6  * Author: Artem Bityutskiy (Битюцкий Артём)
   7  */
   8
   9 /*
  10  * UBI scanning unit.
  11  *
  12  * This unit is responsible for scanning the flash media, checking UBI
  13  * headers and providing complete information about the UBI flash image.
  14  *
  15  * The scanning information is represented by a &struct ubi_scan_info' object.
  16  * Information about found volumes is represented by &struct ubi_scan_volume
  17  * objects which are kept in volume RB-tree with root at the @volumes field.
  18  * The RB-tree is indexed by the volume ID.
  19  *
  20  * Found logical eraseblocks are represented by &struct ubi_scan_leb objects.
  21  * These objects are kept in per-volume RB-trees with the root at the
  22  * corresponding &struct ubi_scan_volume object. To put it differently, we keep
  23  * an RB-tree of per-volume objects and each of these objects is the root of
  24  * RB-tree of per-eraseblock objects.
  25  *
  26  * Corrupted physical eraseblocks are put to the @corr list, free physical
  27  * eraseblocks are put to the @free list and the physical eraseblock to be
  28  * erased are put to the @erase list.
  29  */
  30
  31 #ifdef UBI_LINUX
  32 #include <linux/err.h>
  33 #include <linux/crc32.h>
  34 #include <asm/div64.h>
  35 #endif
  36
  37 #include <ubi_uboot.h>
  38 #include "ubi.h"
  39
  40 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
  41 static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si);
  42 #else
  43 #define paranoid_check_si(ubi, si) 0
  44 #endif
  45
  46 /* Temporary variables used during scanning */
  47 static struct ubi_ec_hdr *ech;
  48 static struct ubi_vid_hdr *vidh;
  49
  50 /**
  51  * add_to_list - add physical eraseblock to a list.
  52  * @si: scanning information
  53  * @pnum: physical eraseblock number to add
  54  * @ec: erase counter of the physical eraseblock
  55  * @list: the list to add to
  56  *
  57  * This function adds physical eraseblock @pnum to free, erase, corrupted or
  58  * alien lists. Returns zero in case of success and a negative error code in
  59  * case of failure.
  60  */
  61 static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
  62                        struct list_head *list)
  63 {
  64         struct ubi_scan_leb *seb;
  65
  66         if (list == &si->free)
  67                 dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
  68         else if (list == &si->erase)
  69                 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
  70         else if (list == &si->corr)
  71                 dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
  72         else if (list == &si->alien)
  73                 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
  74         else
  75                 BUG();
  76
  77         seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
  78         if (!seb)
  79                 return -ENOMEM;
  80
  81         seb->pnum = pnum;
  82         seb->ec = ec;
  83         list_add_tail(&seb->u.list, list);
  84         return 0;
  85 }
  86
  87 /**
  88  * validate_vid_hdr - check that volume identifier header is correct and
  89  * consistent.
  90  * @vid_hdr: the volume identifier header to check
  91  * @sv: information about the volume this logical eraseblock belongs to
  92  * @pnum: physical eraseblock number the VID header came from
  93  *
  94  * This function checks that data stored in @vid_hdr is consistent. Returns
  95  * non-zero if an inconsistency was found and zero if not.
  96  *
  97  * Note, UBI does sanity check of everything it reads from the flash media.
  98  * Most of the checks are done in the I/O unit. Here we check that the
  99  * information in the VID header is consistent to the information in other VID
 100  * headers of the same volume.
 101  */
 102 static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
 103                             const struct ubi_scan_volume *sv, int pnum)
 104 {
 105         int vol_type = vid_hdr->vol_type;
 106         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 107         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 108         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 109
 110         if (sv->leb_count != 0) {
 111                 int sv_vol_type;
 112
 113                 /*
 114                  * This is not the first logical eraseblock belonging to this
 115                  * volume. Ensure that the data in its VID header is consistent
 116                  * to the data in previous logical eraseblock headers.
 117                  */
 118
 119                 if (vol_id != sv->vol_id) {
 120                         dbg_err("inconsistent vol_id");
 121                         goto bad;
 122                 }
 123
 124                 if (sv->vol_type == UBI_STATIC_VOLUME)
 125                         sv_vol_type = UBI_VID_STATIC;
 126                 else
 127                         sv_vol_type = UBI_VID_DYNAMIC;
 128
 129                 if (vol_type != sv_vol_type) {
 130                         dbg_err("inconsistent vol_type");
 131                         goto bad;
 132                 }
 133
 134                 if (used_ebs != sv->used_ebs) {
 135                         dbg_err("inconsistent used_ebs");
 136                         goto bad;
 137                 }
 138
 139                 if (data_pad != sv->data_pad) {
 140                         dbg_err("inconsistent data_pad");
 141                         goto bad;
 142                 }
 143         }
 144
 145         return 0;
 146
 147 bad:
 148         ubi_err("inconsistent VID header at PEB %d", pnum);
 149         ubi_dbg_dump_vid_hdr(vid_hdr);
 150         ubi_dbg_dump_sv(sv);
 151         return -EINVAL;
 152 }
 153
 154 /**
 155  * add_volume - add volume to the scanning information.
 156  * @si: scanning information
 157  * @vol_id: ID of the volume to add
 158  * @pnum: physical eraseblock number
 159  * @vid_hdr: volume identifier header
 160  *
 161  * If the volume corresponding to the @vid_hdr logical eraseblock is already
 162  * present in the scanning information, this function does nothing. Otherwise
 163  * it adds corresponding volume to the scanning information. Returns a pointer
 164  * to the scanning volume object in case of success and a negative error code
 165  * in case of failure.
 166  */
 167 static struct ubi_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id,
 168                                           int pnum,
 169                                           const struct ubi_vid_hdr *vid_hdr)
 170 {
 171         struct ubi_scan_volume *sv;
 172         struct rb_node **p = &si->volumes.rb_node, *parent = NULL;
 173
 174         ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
 175
 176         /* Walk the volume RB-tree to look if this volume is already present */
 177         while (*p) {
 178                 parent = *p;
 179                 sv = rb_entry(parent, struct ubi_scan_volume, rb);
 180
 181                 if (vol_id == sv->vol_id)
 182                         return sv;
 183
 184                 if (vol_id > sv->vol_id)
 185                         p = &(*p)->rb_left;
 186                 else
 187                         p = &(*p)->rb_right;
 188         }
 189
 190         /* The volume is absent - add it */
 191         sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL);
 192         if (!sv)
 193                 return ERR_PTR(-ENOMEM);
 194
 195         sv->highest_lnum = sv->leb_count = 0;
 196         sv->vol_id = vol_id;
 197         sv->root = RB_ROOT;
 198         sv->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 199         sv->data_pad = be32_to_cpu(vid_hdr->data_pad);
 200         sv->compat = vid_hdr->compat;
 201         sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
 202                                                             : UBI_STATIC_VOLUME;
 203         if (vol_id > si->highest_vol_id)
 204                 si->highest_vol_id = vol_id;
 205
 206         rb_link_node(&sv->rb, parent, p);
 207         rb_insert_color(&sv->rb, &si->volumes);
 208         si->vols_found += 1;
 209         dbg_bld("added volume %d", vol_id);
 210         return sv;
 211 }
 212
 213 /**
 214  * compare_lebs - find out which logical eraseblock is newer.
 215  * @ubi: UBI device description object
 216  * @seb: first logical eraseblock to compare
 217  * @pnum: physical eraseblock number of the second logical eraseblock to
 218  * compare
 219  * @vid_hdr: volume identifier header of the second logical eraseblock
 220  *
 221  * This function compares 2 copies of a LEB and informs which one is newer. In
 222  * case of success this function returns a positive value, in case of failure, a
 223  * negative error code is returned. The success return codes use the following
 224  * bits:
 225  *     o bit 0 is cleared: the first PEB (described by @seb) is newer then the
 226  *       second PEB (described by @pnum and @vid_hdr);
 227  *     o bit 0 is set: the second PEB is newer;
 228  *     o bit 1 is cleared: no bit-flips were detected in the newer LEB;
 229  *     o bit 1 is set: bit-flips were detected in the newer LEB;
 230  *     o bit 2 is cleared: the older LEB is not corrupted;
 231  *     o bit 2 is set: the older LEB is corrupted.
 232  */
 233 static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
 234                         int pnum, const struct ubi_vid_hdr *vid_hdr)
 235 {
 236         void *buf;
 237         int len, err, second_is_newer, bitflips = 0, corrupted = 0;
 238         uint32_t data_crc, crc;
 239         struct ubi_vid_hdr *vh = NULL;
 240         unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
 241
 242         if (seb->sqnum == 0 && sqnum2 == 0) {
 243                 long long abs, v1 = seb->leb_ver, v2 = be32_to_cpu(vid_hdr->leb_ver);
 244
 245                 /*
 246                  * UBI constantly increases the logical eraseblock version
 247                  * number and it can overflow. Thus, we have to bear in mind
 248                  * that versions that are close to %0xFFFFFFFF are less then
 249                  * versions that are close to %0.
 250                  *
 251                  * The UBI WL unit guarantees that the number of pending tasks
 252                  * is not greater then %0x7FFFFFFF. So, if the difference
 253                  * between any two versions is greater or equivalent to
 254                  * %0x7FFFFFFF, there was an overflow and the logical
 255                  * eraseblock with lower version is actually newer then the one
 256                  * with higher version.
 257                  *
 258                  * FIXME: but this is anyway obsolete and will be removed at
 259                  * some point.
 260                  */
 261                 dbg_bld("using old crappy leb_ver stuff");
 262
 263                 if (v1 == v2) {
 264                         ubi_err("PEB %d and PEB %d have the same version %lld",
 265                                 seb->pnum, pnum, v1);
 266                         return -EINVAL;
 267                 }
 268
 269                 abs = v1 - v2;
 270                 if (abs < 0)
 271                         abs = -abs;
 272
 273                 if (abs < 0x7FFFFFFF)
 274                         /* Non-overflow situation */
 275                         second_is_newer = (v2 > v1);
 276                 else
 277                         second_is_newer = (v2 < v1);
 278         } else
 279                 /* Obviously the LEB with lower sequence counter is older */
 280                 second_is_newer = sqnum2 > seb->sqnum;
 281
 282         /*
 283          * Now we know which copy is newer. If the copy flag of the PEB with
 284          * newer version is not set, then we just return, otherwise we have to
 285          * check data CRC. For the second PEB we already have the VID header,
 286          * for the first one - we'll need to re-read it from flash.
 287          *
 288          * FIXME: this may be optimized so that we wouldn't read twice.
 289          */
 290
 291         if (second_is_newer) {
 292                 if (!vid_hdr->copy_flag) {
 293                         /* It is not a copy, so it is newer */
 294                         dbg_bld("second PEB %d is newer, copy_flag is unset",
 295                                 pnum);
 296                         return 1;
 297                 }
 298         } else {
 299                 pnum = seb->pnum;
 300
 301                 vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
 302                 if (!vh)
 303                         return -ENOMEM;
 304
 305                 err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
 306                 if (err) {
 307                         if (err == UBI_IO_BITFLIPS)
 308                                 bitflips = 1;
 309                         else {
 310                                 dbg_err("VID of PEB %d header is bad, but it "
 311                                         "was OK earlier", pnum);
 312                                 if (err > 0)
 313                                         err = -EIO;
 314
 315                                 goto out_free_vidh;
 316                         }
 317                 }
 318
 319                 if (!vh->copy_flag) {
 320                         /* It is not a copy, so it is newer */
 321                         dbg_bld("first PEB %d is newer, copy_flag is unset",
 322                                 pnum);
 323                         err = bitflips << 1;
 324                         goto out_free_vidh;
 325                 }
 326
 327                 vid_hdr = vh;
 328         }
 329
 330         /* Read the data of the copy and check the CRC */
 331
 332         len = be32_to_cpu(vid_hdr->data_size);
 333         buf = vmalloc(len);
 334         if (!buf) {
 335                 err = -ENOMEM;
 336                 goto out_free_vidh;
 337         }
 338
 339         err = ubi_io_read_data(ubi, buf, pnum, 0, len);
 340         if (err && err != UBI_IO_BITFLIPS)
 341                 goto out_free_buf;
 342
 343         data_crc = be32_to_cpu(vid_hdr->data_crc);
 344         crc = crc32(UBI_CRC32_INIT, buf, len);
 345         if (crc != data_crc) {
 346                 dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
 347                         pnum, crc, data_crc);
 348                 corrupted = 1;
 349                 bitflips = 0;
 350                 second_is_newer = !second_is_newer;
 351         } else {
 352                 dbg_bld("PEB %d CRC is OK", pnum);
 353                 bitflips = !!err;
 354         }
 355
 356         vfree(buf);
 357         ubi_free_vid_hdr(ubi, vh);
 358
 359         if (second_is_newer)
 360                 dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
 361         else
 362                 dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
 363
 364         return second_is_newer | (bitflips << 1) | (corrupted << 2);
 365
 366 out_free_buf:
 367         vfree(buf);
 368 out_free_vidh:
 369         ubi_free_vid_hdr(ubi, vh);
 370         return err;
 371 }
 372
 373 /**
 374  * ubi_scan_add_used - add information about a physical eraseblock to the
 375  * scanning information.
 376  * @ubi: UBI device description object
 377  * @si: scanning information
 378  * @pnum: the physical eraseblock number
 379  * @ec: erase counter
 380  * @vid_hdr: the volume identifier header
 381  * @bitflips: if bit-flips were detected when this physical eraseblock was read
 382  *
 383  * This function adds information about a used physical eraseblock to the
 384  * 'used' tree of the corresponding volume. The function is rather complex
 385  * because it has to handle cases when this is not the first physical
 386  * eraseblock belonging to the same logical eraseblock, and the newer one has
 387  * to be picked, while the older one has to be dropped. This function returns
 388  * zero in case of success and a negative error code in case of failure.
 389  */
 390 int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
 391                       int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
 392                       int bitflips)
 393 {
 394         int err, vol_id, lnum;
 395         uint32_t leb_ver;
 396         unsigned long long sqnum;
 397         struct ubi_scan_volume *sv;
 398         struct ubi_scan_leb *seb;
 399         struct rb_node **p, *parent = NULL;
 400
 401         vol_id = be32_to_cpu(vid_hdr->vol_id);
 402         lnum = be32_to_cpu(vid_hdr->lnum);
 403         sqnum = be64_to_cpu(vid_hdr->sqnum);
 404         leb_ver = be32_to_cpu(vid_hdr->leb_ver);
 405
 406         dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, ver %u, bitflips %d",
 407                 pnum, vol_id, lnum, ec, sqnum, leb_ver, bitflips);
 408
 409         sv = add_volume(si, vol_id, pnum, vid_hdr);
 410         if (IS_ERR(sv) < 0)
 411                 return PTR_ERR(sv);
 412
 413         if (si->max_sqnum < sqnum)
 414                 si->max_sqnum = sqnum;
 415
 416         /*
 417          * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
 418          * if this is the first instance of this logical eraseblock or not.
 419          */
 420         p = &sv->root.rb_node;
 421         while (*p) {
 422                 int cmp_res;
 423
 424                 parent = *p;
 425                 seb = rb_entry(parent, struct ubi_scan_leb, u.rb);
 426                 if (lnum != seb->lnum) {
 427                         if (lnum < seb->lnum)
 428                                 p = &(*p)->rb_left;
 429                         else
 430                                 p = &(*p)->rb_right;
 431                         continue;
 432                 }
 433
 434                 /*
 435                  * There is already a physical eraseblock describing the same
 436                  * logical eraseblock present.
 437                  */
 438
 439                 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
 440                         "LEB ver %u, EC %d", seb->pnum, seb->sqnum,
 441                         seb->leb_ver, seb->ec);
 442
 443                 /*
 444                  * Make sure that the logical eraseblocks have different
 445                  * versions. Otherwise the image is bad.
 446                  */
 447                 if (seb->leb_ver == leb_ver && leb_ver != 0) {
 448                         ubi_err("two LEBs with same version %u", leb_ver);
 449                         ubi_dbg_dump_seb(seb, 0);
 450                         ubi_dbg_dump_vid_hdr(vid_hdr);
 451                         return -EINVAL;
 452                 }
 453
 454                 /*
 455                  * Make sure that the logical eraseblocks have different
 456                  * sequence numbers. Otherwise the image is bad.
 457                  *
 458                  * FIXME: remove 'sqnum != 0' check when leb_ver is removed.
 459                  */
 460                 if (seb->sqnum == sqnum && sqnum != 0) {
 461                         ubi_err("two LEBs with same sequence number %llu",
 462                                 sqnum);
 463                         ubi_dbg_dump_seb(seb, 0);
 464                         ubi_dbg_dump_vid_hdr(vid_hdr);
 465                         return -EINVAL;
 466                 }
 467
 468                 /*
 469                  * Now we have to drop the older one and preserve the newer
 470                  * one.
 471                  */
 472                 cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
 473                 if (cmp_res < 0)
 474                         return cmp_res;
 475
 476                 if (cmp_res & 1) {
 477                         /*
 478                          * This logical eraseblock is newer then the one
 479                          * found earlier.
 480                          */
 481                         err = validate_vid_hdr(vid_hdr, sv, pnum);
 482                         if (err)
 483                                 return err;
 484
 485                         if (cmp_res & 4)
 486                                 err = add_to_list(si, seb->pnum, seb->ec,
 487                                                   &si->corr);
 488                         else
 489                                 err = add_to_list(si, seb->pnum, seb->ec,
 490                                                   &si->erase);
 491                         if (err)
 492                                 return err;
 493
 494                         seb->ec = ec;
 495                         seb->pnum = pnum;
 496                         seb->scrub = ((cmp_res & 2) || bitflips);
 497                         seb->sqnum = sqnum;
 498                         seb->leb_ver = leb_ver;
 499
 500                         if (sv->highest_lnum == lnum)
 501                                 sv->last_data_size =
 502                                         be32_to_cpu(vid_hdr->data_size);
 503
 504                         return 0;
 505                 } else {
 506                         /*
 507                          * This logical eraseblock is older then the one found
 508                          * previously.
 509                          */
 510                         if (cmp_res & 4)
 511                                 return add_to_list(si, pnum, ec, &si->corr);
 512                         else
 513                                 return add_to_list(si, pnum, ec, &si->erase);
 514                 }
 515         }
 516
 517         /*
 518          * We've met this logical eraseblock for the first time, add it to the
 519          * scanning information.
 520          */
 521
 522         err = validate_vid_hdr(vid_hdr, sv, pnum);
 523         if (err)
 524                 return err;
 525
 526         seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
 527         if (!seb)
 528                 return -ENOMEM;
 529
 530         seb->ec = ec;
 531         seb->pnum = pnum;
 532         seb->lnum = lnum;
 533         seb->sqnum = sqnum;
 534         seb->scrub = bitflips;
 535         seb->leb_ver = leb_ver;
 536
 537         if (sv->highest_lnum <= lnum) {
 538                 sv->highest_lnum = lnum;
 539                 sv->last_data_size = be32_to_cpu(vid_hdr->data_size);
 540         }
 541
 542         sv->leb_count += 1;
 543         rb_link_node(&seb->u.rb, parent, p);
 544         rb_insert_color(&seb->u.rb, &sv->root);
 545         return 0;
 546 }
 547
 548 /**
 549  * ubi_scan_find_sv - find information about a particular volume in the
 550  * scanning information.
 551  * @si: scanning information
 552  * @vol_id: the requested volume ID
 553  *
 554  * This function returns a pointer to the volume description or %NULL if there
 555  * are no data about this volume in the scanning information.
 556  */
 557 struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
 558                                          int vol_id)
 559 {
 560         struct ubi_scan_volume *sv;
 561         struct rb_node *p = si->volumes.rb_node;
 562
 563         while (p) {
 564                 sv = rb_entry(p, struct ubi_scan_volume, rb);
 565
 566                 if (vol_id == sv->vol_id)
 567                         return sv;
 568
 569                 if (vol_id > sv->vol_id)
 570                         p = p->rb_left;
 571                 else
 572                         p = p->rb_right;
 573         }
 574
 575         return NULL;
 576 }
 577
 578 /**
 579  * ubi_scan_find_seb - find information about a particular logical
 580  * eraseblock in the volume scanning information.
 581  * @sv: a pointer to the volume scanning information
 582  * @lnum: the requested logical eraseblock
 583  *
 584  * This function returns a pointer to the scanning logical eraseblock or %NULL
 585  * if there are no data about it in the scanning volume information.
 586  */
 587 struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
 588                                        int lnum)
 589 {
 590         struct ubi_scan_leb *seb;
 591         struct rb_node *p = sv->root.rb_node;
 592
 593         while (p) {
 594                 seb = rb_entry(p, struct ubi_scan_leb, u.rb);
 595
 596                 if (lnum == seb->lnum)
 597                         return seb;
 598
 599                 if (lnum > seb->lnum)
 600                         p = p->rb_left;
 601                 else
 602                         p = p->rb_right;
 603         }
 604
 605         return NULL;
 606 }
 607
 608 /**
 609  * ubi_scan_rm_volume - delete scanning information about a volume.
 610  * @si: scanning information
 611  * @sv: the volume scanning information to delete
 612  */
 613 void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
 614 {
 615         struct rb_node *rb;
 616         struct ubi_scan_leb *seb;
 617
 618         dbg_bld("remove scanning information about volume %d", sv->vol_id);
 619
 620         while ((rb = rb_first(&sv->root))) {
 621                 seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
 622                 rb_erase(&seb->u.rb, &sv->root);
 623                 list_add_tail(&seb->u.list, &si->erase);
 624         }
 625
 626         rb_erase(&sv->rb, &si->volumes);
 627         kfree(sv);
 628         si->vols_found -= 1;
 629 }
 630
 631 /**
 632  * ubi_scan_erase_peb - erase a physical eraseblock.
 633  * @ubi: UBI device description object
 634  * @si: scanning information
 635  * @pnum: physical eraseblock number to erase;
 636  * @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown)
 637  *
 638  * This function erases physical eraseblock 'pnum', and writes the erase
 639  * counter header to it. This function should only be used on UBI device
 640  * initialization stages, when the EBA unit had not been yet initialized. This
 641  * function returns zero in case of success and a negative error code in case
 642  * of failure.
 643  */
 644 int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
 645                        int pnum, int ec)
 646 {
 647         int err;
 648         struct ubi_ec_hdr *ec_hdr;
 649
 650         if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
 651                 /*
 652                  * Erase counter overflow. Upgrade UBI and use 64-bit
 653                  * erase counters internally.
 654                  */
 655                 ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
 656                 return -EINVAL;
 657         }
 658
 659         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
 660         if (!ec_hdr)
 661                 return -ENOMEM;
 662
 663         ec_hdr->ec = cpu_to_be64(ec);
 664
 665         err = ubi_io_sync_erase(ubi, pnum, 0);
 666         if (err < 0)
 667                 goto out_free;
 668
 669         err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
 670
 671 out_free:
 672         kfree(ec_hdr);
 673         return err;
 674 }
 675
 676 /**
 677  * ubi_scan_get_free_peb - get a free physical eraseblock.
 678  * @ubi: UBI device description object
 679  * @si: scanning information
 680  *
 681  * This function returns a free physical eraseblock. It is supposed to be
 682  * called on the UBI initialization stages when the wear-leveling unit is not
 683  * initialized yet. This function picks a physical eraseblocks from one of the
 684  * lists, writes the EC header if it is needed, and removes it from the list.
 685  *
 686  * This function returns scanning physical eraseblock information in case of
 687  * success and an error code in case of failure.
 688  */
 689 struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
 690                                            struct ubi_scan_info *si)
 691 {
 692         int err = 0, i;
 693         struct ubi_scan_leb *seb;
 694
 695         if (!list_empty(&si->free)) {
 696                 seb = list_entry(si->free.next, struct ubi_scan_leb, u.list);
 697                 list_del(&seb->u.list);
 698                 dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec);
 699                 return seb;
 700         }
 701
 702         for (i = 0; i < 2; i++) {
 703                 struct list_head *head;
 704                 struct ubi_scan_leb *tmp_seb;
 705
 706                 if (i == 0)
 707                         head = &si->erase;
 708                 else
 709                         head = &si->corr;
 710
 711                 /*
 712                  * We try to erase the first physical eraseblock from the @head
 713                  * list and pick it if we succeed, or try to erase the
 714                  * next one if not. And so forth. We don't want to take care
 715                  * about bad eraseblocks here - they'll be handled later.
 716                  */
 717                 list_for_each_entry_safe(seb, tmp_seb, head, u.list) {
 718                         if (seb->ec == UBI_SCAN_UNKNOWN_EC)
 719                                 seb->ec = si->mean_ec;
 720
 721                         err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1);
 722                         if (err)
 723                                 continue;
 724
 725                         seb->ec += 1;
 726                         list_del(&seb->u.list);
 727                         dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec);
 728                         return seb;
 729                 }
 730         }
 731
 732         ubi_err("no eraseblocks found");
 733         return ERR_PTR(-ENOSPC);
 734 }
 735
 736 /**
 737  * process_eb - read UBI headers, check them and add corresponding data
 738  * to the scanning information.
 739  * @ubi: UBI device description object
 740  * @si: scanning information
 741  * @pnum: the physical eraseblock number
 742  *
 743  * This function returns a zero if the physical eraseblock was successfully
 744  * handled and a negative error code in case of failure.
 745  */
 746 static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si, int pnum)
 747 {
 748         long long uninitialized_var(ec);
 749         int err, bitflips = 0, vol_id, ec_corr = 0;
 750
 751         dbg_bld("scan PEB %d", pnum);
 752
 753         /* Skip bad physical eraseblocks */
 754         err = ubi_io_is_bad(ubi, pnum);
 755         if (err < 0)
 756                 return err;
 757         else if (err) {
 758                 /*
 759                  * FIXME: this is actually duty of the I/O unit to initialize
 760                  * this, but MTD does not provide enough information.
 761                  */
 762                 si->bad_peb_count += 1;
 763                 return 0;
 764         }
 765
 766         err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
 767         if (err < 0)
 768                 return err;
 769         else if (err == UBI_IO_BITFLIPS)
 770                 bitflips = 1;
 771         else if (err == UBI_IO_PEB_EMPTY)
 772                 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, &si->erase);
 773         else if (err == UBI_IO_BAD_EC_HDR) {
 774                 /*
 775                  * We have to also look at the VID header, possibly it is not
 776                  * corrupted. Set %bitflips flag in order to make this PEB be
 777                  * moved and EC be re-created.
 778                  */
 779                 ec_corr = 1;
 780                 ec = UBI_SCAN_UNKNOWN_EC;
 781                 bitflips = 1;
 782         }
 783
 784         si->is_empty = 0;
 785
 786         if (!ec_corr) {
 787                 /* Make sure UBI version is OK */
 788                 if (ech->version != UBI_VERSION) {
 789                         ubi_err("this UBI version is %d, image version is %d",
 790                                 UBI_VERSION, (int)ech->version);
 791                         return -EINVAL;
 792                 }
 793
 794                 ec = be64_to_cpu(ech->ec);
 795                 if (ec > UBI_MAX_ERASECOUNTER) {
 796                         /*
 797                          * Erase counter overflow. The EC headers have 64 bits
 798                          * reserved, but we anyway make use of only 31 bit
 799                          * values, as this seems to be enough for any existing
 800                          * flash. Upgrade UBI and use 64-bit erase counters
 801                          * internally.
 802                          */
 803                         ubi_err("erase counter overflow, max is %d",
 804                                 UBI_MAX_ERASECOUNTER);
 805                         ubi_dbg_dump_ec_hdr(ech);
 806                         return -EINVAL;
 807                 }
 808         }
 809
 810         /* OK, we've done with the EC header, let's look at the VID header */
 811
 812         err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
 813         if (err < 0)
 814                 return err;
 815         else if (err == UBI_IO_BITFLIPS)
 816                 bitflips = 1;
 817         else if (err == UBI_IO_BAD_VID_HDR ||
 818                  (err == UBI_IO_PEB_FREE && ec_corr)) {
 819                 /* VID header is corrupted */
 820                 err = add_to_list(si, pnum, ec, &si->corr);
 821                 if (err)
 822                         return err;
 823                 goto adjust_mean_ec;
 824         } else if (err == UBI_IO_PEB_FREE) {
 825                 /* No VID header - the physical eraseblock is free */
 826                 err = add_to_list(si, pnum, ec, &si->free);
 827                 if (err)
 828                         return err;
 829                 goto adjust_mean_ec;
 830         }
 831
 832         vol_id = be32_to_cpu(vidh->vol_id);
 833         if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
 834                 int lnum = be32_to_cpu(vidh->lnum);
 835
 836                 /* Unsupported internal volume */
 837                 switch (vidh->compat) {
 838                 case UBI_COMPAT_DELETE:
 839                         ubi_msg("\"delete\" compatible internal volume %d:%d"
 840                                 " found, remove it", vol_id, lnum);
 841                         err = add_to_list(si, pnum, ec, &si->corr);
 842                         if (err)
 843                                 return err;
 844                         break;
 845
 846                 case UBI_COMPAT_RO:
 847                         ubi_msg("read-only compatible internal volume %d:%d"
 848                                 " found, switch to read-only mode",
 849                                 vol_id, lnum);
 850                         ubi->ro_mode = 1;
 851                         break;
 852
 853                 case UBI_COMPAT_PRESERVE:
 854                         ubi_msg("\"preserve\" compatible internal volume %d:%d"
 855                                 " found", vol_id, lnum);
 856                         err = add_to_list(si, pnum, ec, &si->alien);
 857                         if (err)
 858                                 return err;
 859                         si->alien_peb_count += 1;
 860                         return 0;
 861
 862                 case UBI_COMPAT_REJECT:
 863                         ubi_err("incompatible internal volume %d:%d found",
 864                                 vol_id, lnum);
 865                         return -EINVAL;
 866                 }
 867         }
 868
 869         /* Both UBI headers seem to be fine */
 870         err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips);
 871         if (err)
 872                 return err;
 873
 874 adjust_mean_ec:
 875         if (!ec_corr) {
 876                 si->ec_sum += ec;
 877                 si->ec_count += 1;
 878                 if (ec > si->max_ec)
 879                         si->max_ec = ec;
 880                 if (ec < si->min_ec)
 881                         si->min_ec = ec;
 882         }
 883
 884         return 0;
 885 }
 886
 887 /**
 888  * ubi_scan - scan an MTD device.
 889  * @ubi: UBI device description object
 890  *
 891  * This function does full scanning of an MTD device and returns complete
 892  * information about it. In case of failure, an error code is returned.
 893  */
 894 struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
 895 {
 896         int err, pnum;
 897         struct rb_node *rb1, *rb2;
 898         struct ubi_scan_volume *sv;
 899         struct ubi_scan_leb *seb;
 900         struct ubi_scan_info *si;
 901
 902         si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL);
 903         if (!si)
 904                 return ERR_PTR(-ENOMEM);
 905
 906         INIT_LIST_HEAD(&si->corr);
 907         INIT_LIST_HEAD(&si->free);
 908         INIT_LIST_HEAD(&si->erase);
 909         INIT_LIST_HEAD(&si->alien);
 910         si->volumes = RB_ROOT;
 911         si->is_empty = 1;
 912
 913         err = -ENOMEM;
 914         ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
 915         if (!ech)
 916                 goto out_si;
 917
 918         vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
 919         if (!vidh)
 920                 goto out_ech;
 921
 922         for (pnum = 0; pnum < ubi->peb_count; pnum++) {
 923                 cond_resched();
 924
 925                 dbg_msg("process PEB %d", pnum);
 926                 err = process_eb(ubi, si, pnum);
 927                 if (err < 0)
 928                         goto out_vidh;
 929         }
 930
 931         dbg_msg("scanning is finished");
 932
 933         /* Calculate mean erase counter */
 934         if (si->ec_count) {
 935                 do_div(si->ec_sum, si->ec_count);
 936                 si->mean_ec = si->ec_sum;
 937         }
 938
 939         if (si->is_empty)
 940                 ubi_msg("empty MTD device detected");
 941
 942         /*
 943          * In case of unknown erase counter we use the mean erase counter
 944          * value.
 945          */
 946         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
 947                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
 948                         if (seb->ec == UBI_SCAN_UNKNOWN_EC)
 949                                 seb->ec = si->mean_ec;
 950         }
 951
 952         list_for_each_entry(seb, &si->free, u.list) {
 953                 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
 954                         seb->ec = si->mean_ec;
 955         }
 956
 957         list_for_each_entry(seb, &si->corr, u.list)
 958                 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
 959                         seb->ec = si->mean_ec;
 960
 961         list_for_each_entry(seb, &si->erase, u.list)
 962                 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
 963                         seb->ec = si->mean_ec;
 964
 965         err = paranoid_check_si(ubi, si);
 966         if (err) {
 967                 if (err > 0)
 968                         err = -EINVAL;
 969                 goto out_vidh;
 970         }
 971
 972         ubi_free_vid_hdr(ubi, vidh);
 973         kfree(ech);
 974
 975         return si;
 976
 977 out_vidh:
 978         ubi_free_vid_hdr(ubi, vidh);
 979 out_ech:
 980         kfree(ech);
 981 out_si:
 982         ubi_scan_destroy_si(si);
 983         return ERR_PTR(err);
 984 }
 985
 986 /**
 987  * destroy_sv - free the scanning volume information
 988  * @sv: scanning volume information
 989  *
 990  * This function destroys the volume RB-tree (@sv->root) and the scanning
 991  * volume information.
 992  */
 993 static void destroy_sv(struct ubi_scan_volume *sv)
 994 {
 995         struct ubi_scan_leb *seb;
 996         struct rb_node *this = sv->root.rb_node;
 997
 998         while (this) {
 999                 if (this->rb_left)
1000                         this = this->rb_left;
1001                 else if (this->rb_right)
1002                         this = this->rb_right;
1003                 else {
1004                         seb = rb_entry(this, struct ubi_scan_leb, u.rb);
1005                         this = rb_parent(this);
1006                         if (this) {
1007                                 if (this->rb_left == &seb->u.rb)
1008                                         this->rb_left = NULL;
1009                                 else
1010                                         this->rb_right = NULL;
1011                         }
1012
1013                         kfree(seb);
1014                 }
1015         }
1016         kfree(sv);
1017 }
1018
1019 /**
1020  * ubi_scan_destroy_si - destroy scanning information.
1021  * @si: scanning information
1022  */
1023 void ubi_scan_destroy_si(struct ubi_scan_info *si)
1024 {
1025         struct ubi_scan_leb *seb, *seb_tmp;
1026         struct ubi_scan_volume *sv;
1027         struct rb_node *rb;
1028
1029         list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {
1030                 list_del(&seb->u.list);
1031                 kfree(seb);
1032         }
1033         list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
1034                 list_del(&seb->u.list);
1035                 kfree(seb);
1036         }
1037         list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
1038                 list_del(&seb->u.list);
1039                 kfree(seb);
1040         }
1041         list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
1042                 list_del(&seb->u.list);
1043                 kfree(seb);
1044         }
1045
1046         /* Destroy the volume RB-tree */
1047         rb = si->volumes.rb_node;
1048         while (rb) {
1049                 if (rb->rb_left)
1050                         rb = rb->rb_left;
1051                 else if (rb->rb_right)
1052                         rb = rb->rb_right;
1053                 else {
1054                         sv = rb_entry(rb, struct ubi_scan_volume, rb);
1055
1056                         rb = rb_parent(rb);
1057                         if (rb) {
1058                                 if (rb->rb_left == &sv->rb)
1059                                         rb->rb_left = NULL;
1060                                 else
1061                                         rb->rb_right = NULL;
1062                         }
1063
1064                         destroy_sv(sv);
1065                 }
1066         }
1067
1068         kfree(si);
1069 }
1070
1071 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1072
1073 /**
1074  * paranoid_check_si - check if the scanning information is correct and
1075  * consistent.
1076  * @ubi: UBI device description object
1077  * @si: scanning information
1078  *
1079  * This function returns zero if the scanning information is all right, %1 if
1080  * not and a negative error code if an error occurred.
1081  */
1082 static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
1083 {
1084         int pnum, err, vols_found = 0;
1085         struct rb_node *rb1, *rb2;
1086         struct ubi_scan_volume *sv;
1087         struct ubi_scan_leb *seb, *last_seb;
1088         uint8_t *buf;
1089
1090         /*
1091          * At first, check that scanning information is OK.
1092          */
1093         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1094                 int leb_count = 0;
1095
1096                 cond_resched();
1097
1098                 vols_found += 1;
1099
1100                 if (si->is_empty) {
1101                         ubi_err("bad is_empty flag");
1102                         goto bad_sv;
1103                 }
1104
1105                 if (sv->vol_id < 0 || sv->highest_lnum < 0 ||
1106                     sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 ||
1107                     sv->data_pad < 0 || sv->last_data_size < 0) {
1108                         ubi_err("negative values");
1109                         goto bad_sv;
1110                 }
1111
1112                 if (sv->vol_id >= UBI_MAX_VOLUMES &&
1113                     sv->vol_id < UBI_INTERNAL_VOL_START) {
1114                         ubi_err("bad vol_id");
1115                         goto bad_sv;
1116                 }
1117
1118                 if (sv->vol_id > si->highest_vol_id) {
1119                         ubi_err("highest_vol_id is %d, but vol_id %d is there",
1120                                 si->highest_vol_id, sv->vol_id);
1121                         goto out;
1122                 }
1123
1124                 if (sv->vol_type != UBI_DYNAMIC_VOLUME &&
1125                     sv->vol_type != UBI_STATIC_VOLUME) {
1126                         ubi_err("bad vol_type");
1127                         goto bad_sv;
1128                 }
1129
1130                 if (sv->data_pad > ubi->leb_size / 2) {
1131                         ubi_err("bad data_pad");
1132                         goto bad_sv;
1133                 }
1134
1135                 last_seb = NULL;
1136                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1137                         cond_resched();
1138
1139                         last_seb = seb;
1140                         leb_count += 1;
1141
1142                         if (seb->pnum < 0 || seb->ec < 0) {
1143                                 ubi_err("negative values");
1144                                 goto bad_seb;
1145                         }
1146
1147                         if (seb->ec < si->min_ec) {
1148                                 ubi_err("bad si->min_ec (%d), %d found",
1149                                         si->min_ec, seb->ec);
1150                                 goto bad_seb;
1151                         }
1152
1153                         if (seb->ec > si->max_ec) {
1154                                 ubi_err("bad si->max_ec (%d), %d found",
1155                                         si->max_ec, seb->ec);
1156                                 goto bad_seb;
1157                         }
1158
1159                         if (seb->pnum >= ubi->peb_count) {
1160                                 ubi_err("too high PEB number %d, total PEBs %d",
1161                                         seb->pnum, ubi->peb_count);
1162                                 goto bad_seb;
1163                         }
1164
1165                         if (sv->vol_type == UBI_STATIC_VOLUME) {
1166                                 if (seb->lnum >= sv->used_ebs) {
1167                                         ubi_err("bad lnum or used_ebs");
1168                                         goto bad_seb;
1169                                 }
1170                         } else {
1171                                 if (sv->used_ebs != 0) {
1172                                         ubi_err("non-zero used_ebs");
1173                                         goto bad_seb;
1174                                 }
1175                         }
1176
1177                         if (seb->lnum > sv->highest_lnum) {
1178                                 ubi_err("incorrect highest_lnum or lnum");
1179                                 goto bad_seb;
1180                         }
1181                 }
1182
1183                 if (sv->leb_count != leb_count) {
1184                         ubi_err("bad leb_count, %d objects in the tree",
1185                                 leb_count);
1186                         goto bad_sv;
1187                 }
1188
1189                 if (!last_seb)
1190                         continue;
1191
1192                 seb = last_seb;
1193
1194                 if (seb->lnum != sv->highest_lnum) {
1195                         ubi_err("bad highest_lnum");
1196                         goto bad_seb;
1197                 }
1198         }
1199
1200         if (vols_found != si->vols_found) {
1201                 ubi_err("bad si->vols_found %d, should be %d",
1202                         si->vols_found, vols_found);
1203                 goto out;
1204         }
1205
1206         /* Check that scanning information is correct */
1207         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1208                 last_seb = NULL;
1209                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1210                         int vol_type;
1211
1212                         cond_resched();
1213
1214                         last_seb = seb;
1215
1216                         err = ubi_io_read_vid_hdr(ubi, seb->pnum, vidh, 1);
1217                         if (err && err != UBI_IO_BITFLIPS) {
1218                                 ubi_err("VID header is not OK (%d)", err);
1219                                 if (err > 0)
1220                                         err = -EIO;
1221                                 return err;
1222                         }
1223
1224                         vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1225                                    UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1226                         if (sv->vol_type != vol_type) {
1227                                 ubi_err("bad vol_type");
1228                                 goto bad_vid_hdr;
1229                         }
1230
1231                         if (seb->sqnum != be64_to_cpu(vidh->sqnum)) {
1232                                 ubi_err("bad sqnum %llu", seb->sqnum);
1233                                 goto bad_vid_hdr;
1234                         }
1235
1236                         if (sv->vol_id != be32_to_cpu(vidh->vol_id)) {
1237                                 ubi_err("bad vol_id %d", sv->vol_id);
1238                                 goto bad_vid_hdr;
1239                         }
1240
1241                         if (sv->compat != vidh->compat) {
1242                                 ubi_err("bad compat %d", vidh->compat);
1243                                 goto bad_vid_hdr;
1244                         }
1245
1246                         if (seb->lnum != be32_to_cpu(vidh->lnum)) {
1247                                 ubi_err("bad lnum %d", seb->lnum);
1248                                 goto bad_vid_hdr;
1249                         }
1250
1251                         if (sv->used_ebs != be32_to_cpu(vidh->used_ebs)) {
1252                                 ubi_err("bad used_ebs %d", sv->used_ebs);
1253                                 goto bad_vid_hdr;
1254                         }
1255
1256                         if (sv->data_pad != be32_to_cpu(vidh->data_pad)) {
1257                                 ubi_err("bad data_pad %d", sv->data_pad);
1258                                 goto bad_vid_hdr;
1259                         }
1260
1261                         if (seb->leb_ver != be32_to_cpu(vidh->leb_ver)) {
1262                                 ubi_err("bad leb_ver %u", seb->leb_ver);
1263                                 goto bad_vid_hdr;
1264                         }
1265                 }
1266
1267                 if (!last_seb)
1268                         continue;
1269
1270                 if (sv->highest_lnum != be32_to_cpu(vidh->lnum)) {
1271                         ubi_err("bad highest_lnum %d", sv->highest_lnum);
1272                         goto bad_vid_hdr;
1273                 }
1274
1275                 if (sv->last_data_size != be32_to_cpu(vidh->data_size)) {
1276                         ubi_err("bad last_data_size %d", sv->last_data_size);
1277                         goto bad_vid_hdr;
1278                 }
1279         }
1280
1281         /*
1282          * Make sure that all the physical eraseblocks are in one of the lists
1283          * or trees.
1284          */
1285         buf = kzalloc(ubi->peb_count, GFP_KERNEL);
1286         if (!buf)
1287                 return -ENOMEM;
1288
1289         for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1290                 err = ubi_io_is_bad(ubi, pnum);
1291                 if (err < 0) {
1292                         kfree(buf);
1293                         return err;
1294                 }
1295                 else if (err)
1296                         buf[pnum] = 1;
1297         }
1298
1299         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb)
1300                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1301                         buf[seb->pnum] = 1;
1302
1303         list_for_each_entry(seb, &si->free, u.list)
1304                 buf[seb->pnum] = 1;
1305
1306         list_for_each_entry(seb, &si->corr, u.list)
1307                 buf[seb->pnum] = 1;
1308
1309         list_for_each_entry(seb, &si->erase, u.list)
1310                 buf[seb->pnum] = 1;
1311
1312         list_for_each_entry(seb, &si->alien, u.list)
1313                 buf[seb->pnum] = 1;
1314
1315         err = 0;
1316         for (pnum = 0; pnum < ubi->peb_count; pnum++)
1317                 if (!buf[pnum]) {
1318                         ubi_err("PEB %d is not referred", pnum);
1319                         err = 1;
1320                 }
1321
1322         kfree(buf);
1323         if (err)
1324                 goto out;
1325         return 0;
1326
1327 bad_seb:
1328         ubi_err("bad scanning information about LEB %d", seb->lnum);
1329         ubi_dbg_dump_seb(seb, 0);
1330         ubi_dbg_dump_sv(sv);
1331         goto out;
1332
1333 bad_sv:
1334         ubi_err("bad scanning information about volume %d", sv->vol_id);
1335         ubi_dbg_dump_sv(sv);
1336         goto out;
1337
1338 bad_vid_hdr:
1339         ubi_err("bad scanning information about volume %d", sv->vol_id);
1340         ubi_dbg_dump_sv(sv);
1341         ubi_dbg_dump_vid_hdr(vidh);
1342
1343 out:
1344         ubi_dbg_dump_stack();
1345         return 1;
1346 }
1347
1348 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */