drivers/mtd/ubi/scan.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  12  * the GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Author: Artem Bityutskiy (Битюцкий Артём)
  19  */
  20
  21 /*
  22  * UBI scanning sub-system.
  23  *
  24  * This sub-system is responsible for scanning the flash media, checking UBI
  25  * headers and providing complete information about the UBI flash image.
  26  *
  27  * The scanning information is represented by a &struct ubi_scan_info' object.
  28  * Information about found volumes is represented by &struct ubi_scan_volume
  29  * objects which are kept in volume RB-tree with root at the @volumes field.
  30  * The RB-tree is indexed by the volume ID.
  31  *
  32  * Found logical eraseblocks are represented by &struct ubi_scan_leb objects.
  33  * These objects are kept in per-volume RB-trees with the root at the
  34  * corresponding &struct ubi_scan_volume object. To put it differently, we keep
  35  * an RB-tree of per-volume objects and each of these objects is the root of
  36  * RB-tree of per-eraseblock objects.
  37  *
  38  * Corrupted physical eraseblocks are put to the @corr list, free physical
  39  * eraseblocks are put to the @free list and the physical eraseblock to be
  40  * erased are put to the @erase list.
  41  */
  42
  43 #include <linux/err.h>
  44 #include <linux/slab.h>
  45 #include <linux/crc32.h>
  46 #include <linux/math64.h>
  47 #include <linux/random.h>
  48 #include "ubi.h"
  49
  50 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
  51 static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si);
  52 #else
  53 #define paranoid_check_si(ubi, si) 0
  54 #endif
  55
  56 /* Temporary variables used during scanning */
  57 static struct ubi_ec_hdr *ech;
  58 static struct ubi_vid_hdr *vidh;
  59
  60 /**
  61  * add_to_list - add physical eraseblock to a list.
  62  * @si: scanning information
  63  * @pnum: physical eraseblock number to add
  64  * @ec: erase counter of the physical eraseblock
  65  * @list: the list to add to
  66  *
  67  * This function adds physical eraseblock @pnum to free, erase, or alien lists.
  68  * Returns zero in case of success and a negative error code in case of
  69  * failure.
  70  */
  71 static int add_to_list(struct ubi_scan_info *si, int pnum, int ec,
  72                        struct list_head *list)
  73 {
  74         struct ubi_scan_leb *seb;
  75
  76         if (list == &si->free) {
  77                 dbg_bld("add to free: PEB %d, EC %d", pnum, ec);
  78                 si->free_peb_count += 1;
  79         } else if (list == &si->erase) {
  80                 dbg_bld("add to erase: PEB %d, EC %d", pnum, ec);
  81                 si->erase_peb_count += 1;
  82         } else if (list == &si->alien) {
  83                 dbg_bld("add to alien: PEB %d, EC %d", pnum, ec);
  84                 si->alien_peb_count += 1;
  85         } else
  86                 BUG();
  87
  88         seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
  89         if (!seb)
  90                 return -ENOMEM;
  91
  92         seb->pnum = pnum;
  93         seb->ec = ec;
  94         list_add_tail(&seb->u.list, list);
  95         return 0;
  96 }
  97
  98 /**
  99  * add_corrupted - add a corrupted physical eraseblock.
 100  * @si: scanning information
 101  * @pnum: physical eraseblock number to add
 102  * @ec: erase counter of the physical eraseblock
 103  *
 104  * This function adds corrupted physical eraseblock @pnum to the 'corr' list.
 105  * Returns zero in case of success and a negative error code in case of
 106  * failure.
 107  */
 108 static int add_corrupted(struct ubi_scan_info *si, int pnum, int ec)
 109 {
 110         struct ubi_scan_leb *seb;
 111
 112         dbg_bld("add to corrupted: PEB %d, EC %d", pnum, ec);
 113
 114         seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
 115         if (!seb)
 116                 return -ENOMEM;
 117
 118         si->corr_peb_count += 1;
 119         seb->pnum = pnum;
 120         seb->ec = ec;
 121         list_add(&seb->u.list, &si->corr);
 122         return 0;
 123 }
 124
 125 /**
 126  * validate_vid_hdr - check volume identifier header.
 127  * @vid_hdr: the volume identifier header to check
 128  * @sv: information about the volume this logical eraseblock belongs to
 129  * @pnum: physical eraseblock number the VID header came from
 130  *
 131  * This function checks that data stored in @vid_hdr is consistent. Returns
 132  * non-zero if an inconsistency was found and zero if not.
 133  *
 134  * Note, UBI does sanity check of everything it reads from the flash media.
 135  * Most of the checks are done in the I/O sub-system. Here we check that the
 136  * information in the VID header is consistent to the information in other VID
 137  * headers of the same volume.
 138  */
 139 static int validate_vid_hdr(const struct ubi_vid_hdr *vid_hdr,
 140                             const struct ubi_scan_volume *sv, int pnum)
 141 {
 142         int vol_type = vid_hdr->vol_type;
 143         int vol_id = be32_to_cpu(vid_hdr->vol_id);
 144         int used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 145         int data_pad = be32_to_cpu(vid_hdr->data_pad);
 146
 147         if (sv->leb_count != 0) {
 148                 int sv_vol_type;
 149
 150                 /*
 151                  * This is not the first logical eraseblock belonging to this
 152                  * volume. Ensure that the data in its VID header is consistent
 153                  * to the data in previous logical eraseblock headers.
 154                  */
 155
 156                 if (vol_id != sv->vol_id) {
 157                         dbg_err("inconsistent vol_id");
 158                         goto bad;
 159                 }
 160
 161                 if (sv->vol_type == UBI_STATIC_VOLUME)
 162                         sv_vol_type = UBI_VID_STATIC;
 163                 else
 164                         sv_vol_type = UBI_VID_DYNAMIC;
 165
 166                 if (vol_type != sv_vol_type) {
 167                         dbg_err("inconsistent vol_type");
 168                         goto bad;
 169                 }
 170
 171                 if (used_ebs != sv->used_ebs) {
 172                         dbg_err("inconsistent used_ebs");
 173                         goto bad;
 174                 }
 175
 176                 if (data_pad != sv->data_pad) {
 177                         dbg_err("inconsistent data_pad");
 178                         goto bad;
 179                 }
 180         }
 181
 182         return 0;
 183
 184 bad:
 185         ubi_err("inconsistent VID header at PEB %d", pnum);
 186         ubi_dbg_dump_vid_hdr(vid_hdr);
 187         ubi_dbg_dump_sv(sv);
 188         return -EINVAL;
 189 }
 190
 191 /**
 192  * add_volume - add volume to the scanning information.
 193  * @si: scanning information
 194  * @vol_id: ID of the volume to add
 195  * @pnum: physical eraseblock number
 196  * @vid_hdr: volume identifier header
 197  *
 198  * If the volume corresponding to the @vid_hdr logical eraseblock is already
 199  * present in the scanning information, this function does nothing. Otherwise
 200  * it adds corresponding volume to the scanning information. Returns a pointer
 201  * to the scanning volume object in case of success and a negative error code
 202  * in case of failure.
 203  */
 204 static struct ubi_scan_volume *add_volume(struct ubi_scan_info *si, int vol_id,
 205                                           int pnum,
 206                                           const struct ubi_vid_hdr *vid_hdr)
 207 {
 208         struct ubi_scan_volume *sv;
 209         struct rb_node **p = &si->volumes.rb_node, *parent = NULL;
 210
 211         ubi_assert(vol_id == be32_to_cpu(vid_hdr->vol_id));
 212
 213         /* Walk the volume RB-tree to look if this volume is already present */
 214         while (*p) {
 215                 parent = *p;
 216                 sv = rb_entry(parent, struct ubi_scan_volume, rb);
 217
 218                 if (vol_id == sv->vol_id)
 219                         return sv;
 220
 221                 if (vol_id > sv->vol_id)
 222                         p = &(*p)->rb_left;
 223                 else
 224                         p = &(*p)->rb_right;
 225         }
 226
 227         /* The volume is absent - add it */
 228         sv = kmalloc(sizeof(struct ubi_scan_volume), GFP_KERNEL);
 229         if (!sv)
 230                 return ERR_PTR(-ENOMEM);
 231
 232         sv->highest_lnum = sv->leb_count = 0;
 233         sv->vol_id = vol_id;
 234         sv->root = RB_ROOT;
 235         sv->used_ebs = be32_to_cpu(vid_hdr->used_ebs);
 236         sv->data_pad = be32_to_cpu(vid_hdr->data_pad);
 237         sv->compat = vid_hdr->compat;
 238         sv->vol_type = vid_hdr->vol_type == UBI_VID_DYNAMIC ? UBI_DYNAMIC_VOLUME
 239                                                             : UBI_STATIC_VOLUME;
 240         if (vol_id > si->highest_vol_id)
 241                 si->highest_vol_id = vol_id;
 242
 243         rb_link_node(&sv->rb, parent, p);
 244         rb_insert_color(&sv->rb, &si->volumes);
 245         si->vols_found += 1;
 246         dbg_bld("added volume %d", vol_id);
 247         return sv;
 248 }
 249
 250 /**
 251  * compare_lebs - find out which logical eraseblock is newer.
 252  * @ubi: UBI device description object
 253  * @seb: first logical eraseblock to compare
 254  * @pnum: physical eraseblock number of the second logical eraseblock to
 255  * compare
 256  * @vid_hdr: volume identifier header of the second logical eraseblock
 257  *
 258  * This function compares 2 copies of a LEB and informs which one is newer. In
 259  * case of success this function returns a positive value, in case of failure, a
 260  * negative error code is returned. The success return codes use the following
 261  * bits:
 262  *     o bit 0 is cleared: the first PEB (described by @seb) is newer than the
 263  *       second PEB (described by @pnum and @vid_hdr);
 264  *     o bit 0 is set: the second PEB is newer;
 265  *     o bit 1 is cleared: no bit-flips were detected in the newer LEB;
 266  *     o bit 1 is set: bit-flips were detected in the newer LEB;
 267  *     o bit 2 is cleared: the older LEB is not corrupted;
 268  *     o bit 2 is set: the older LEB is corrupted.
 269  */
 270 static int compare_lebs(struct ubi_device *ubi, const struct ubi_scan_leb *seb,
 271                         int pnum, const struct ubi_vid_hdr *vid_hdr)
 272 {
 273         void *buf;
 274         int len, err, second_is_newer, bitflips = 0, corrupted = 0;
 275         uint32_t data_crc, crc;
 276         struct ubi_vid_hdr *vh = NULL;
 277         unsigned long long sqnum2 = be64_to_cpu(vid_hdr->sqnum);
 278
 279         if (sqnum2 == seb->sqnum) {
 280                 /*
 281                  * This must be a really ancient UBI image which has been
 282                  * created before sequence numbers support has been added. At
 283                  * that times we used 32-bit LEB versions stored in logical
 284                  * eraseblocks. That was before UBI got into mainline. We do not
 285                  * support these images anymore. Well, those images will work
 286                  * still work, but only if no unclean reboots happened.
 287                  */
 288                 ubi_err("unsupported on-flash UBI format\n");
 289                 return -EINVAL;
 290         }
 291
 292         /* Obviously the LEB with lower sequence counter is older */
 293         second_is_newer = !!(sqnum2 > seb->sqnum);
 294
 295         /*
 296          * Now we know which copy is newer. If the copy flag of the PEB with
 297          * newer version is not set, then we just return, otherwise we have to
 298          * check data CRC. For the second PEB we already have the VID header,
 299          * for the first one - we'll need to re-read it from flash.
 300          *
 301          * Note: this may be optimized so that we wouldn't read twice.
 302          */
 303
 304         if (second_is_newer) {
 305                 if (!vid_hdr->copy_flag) {
 306                         /* It is not a copy, so it is newer */
 307                         dbg_bld("second PEB %d is newer, copy_flag is unset",
 308                                 pnum);
 309                         return 1;
 310                 }
 311         } else {
 312                 pnum = seb->pnum;
 313
 314                 vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
 315                 if (!vh)
 316                         return -ENOMEM;
 317
 318                 err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
 319                 if (err) {
 320                         if (err == UBI_IO_BITFLIPS)
 321                                 bitflips = 1;
 322                         else {
 323                                 dbg_err("VID of PEB %d header is bad, but it "
 324                                         "was OK earlier", pnum);
 325                                 if (err > 0)
 326                                         err = -EIO;
 327
 328                                 goto out_free_vidh;
 329                         }
 330                 }
 331
 332                 if (!vh->copy_flag) {
 333                         /* It is not a copy, so it is newer */
 334                         dbg_bld("first PEB %d is newer, copy_flag is unset",
 335                                 pnum);
 336                         err = bitflips << 1;
 337                         goto out_free_vidh;
 338                 }
 339
 340                 vid_hdr = vh;
 341         }
 342
 343         /* Read the data of the copy and check the CRC */
 344
 345         len = be32_to_cpu(vid_hdr->data_size);
 346         buf = vmalloc(len);
 347         if (!buf) {
 348                 err = -ENOMEM;
 349                 goto out_free_vidh;
 350         }
 351
 352         err = ubi_io_read_data(ubi, buf, pnum, 0, len);
 353         if (err && err != UBI_IO_BITFLIPS && err != -EBADMSG)
 354                 goto out_free_buf;
 355
 356         data_crc = be32_to_cpu(vid_hdr->data_crc);
 357         crc = crc32(UBI_CRC32_INIT, buf, len);
 358         if (crc != data_crc) {
 359                 dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
 360                         pnum, crc, data_crc);
 361                 corrupted = 1;
 362                 bitflips = 0;
 363                 second_is_newer = !second_is_newer;
 364         } else {
 365                 dbg_bld("PEB %d CRC is OK", pnum);
 366                 bitflips = !!err;
 367         }
 368
 369         vfree(buf);
 370         ubi_free_vid_hdr(ubi, vh);
 371
 372         if (second_is_newer)
 373                 dbg_bld("second PEB %d is newer, copy_flag is set", pnum);
 374         else
 375                 dbg_bld("first PEB %d is newer, copy_flag is set", pnum);
 376
 377         return second_is_newer | (bitflips << 1) | (corrupted << 2);
 378
 379 out_free_buf:
 380         vfree(buf);
 381 out_free_vidh:
 382         ubi_free_vid_hdr(ubi, vh);
 383         return err;
 384 }
 385
 386 /**
 387  * ubi_scan_add_used - add physical eraseblock to the scanning information.
 388  * @ubi: UBI device description object
 389  * @si: scanning information
 390  * @pnum: the physical eraseblock number
 391  * @ec: erase counter
 392  * @vid_hdr: the volume identifier header
 393  * @bitflips: if bit-flips were detected when this physical eraseblock was read
 394  *
 395  * This function adds information about a used physical eraseblock to the
 396  * 'used' tree of the corresponding volume. The function is rather complex
 397  * because it has to handle cases when this is not the first physical
 398  * eraseblock belonging to the same logical eraseblock, and the newer one has
 399  * to be picked, while the older one has to be dropped. This function returns
 400  * zero in case of success and a negative error code in case of failure.
 401  */
 402 int ubi_scan_add_used(struct ubi_device *ubi, struct ubi_scan_info *si,
 403                       int pnum, int ec, const struct ubi_vid_hdr *vid_hdr,
 404                       int bitflips)
 405 {
 406         int err, vol_id, lnum;
 407         unsigned long long sqnum;
 408         struct ubi_scan_volume *sv;
 409         struct ubi_scan_leb *seb;
 410         struct rb_node **p, *parent = NULL;
 411
 412         vol_id = be32_to_cpu(vid_hdr->vol_id);
 413         lnum = be32_to_cpu(vid_hdr->lnum);
 414         sqnum = be64_to_cpu(vid_hdr->sqnum);
 415
 416         dbg_bld("PEB %d, LEB %d:%d, EC %d, sqnum %llu, bitflips %d",
 417                 pnum, vol_id, lnum, ec, sqnum, bitflips);
 418
 419         sv = add_volume(si, vol_id, pnum, vid_hdr);
 420         if (IS_ERR(sv))
 421                 return PTR_ERR(sv);
 422
 423         if (si->max_sqnum < sqnum)
 424                 si->max_sqnum = sqnum;
 425
 426         /*
 427          * Walk the RB-tree of logical eraseblocks of volume @vol_id to look
 428          * if this is the first instance of this logical eraseblock or not.
 429          */
 430         p = &sv->root.rb_node;
 431         while (*p) {
 432                 int cmp_res;
 433
 434                 parent = *p;
 435                 seb = rb_entry(parent, struct ubi_scan_leb, u.rb);
 436                 if (lnum != seb->lnum) {
 437                         if (lnum < seb->lnum)
 438                                 p = &(*p)->rb_left;
 439                         else
 440                                 p = &(*p)->rb_right;
 441                         continue;
 442                 }
 443
 444                 /*
 445                  * There is already a physical eraseblock describing the same
 446                  * logical eraseblock present.
 447                  */
 448
 449                 dbg_bld("this LEB already exists: PEB %d, sqnum %llu, "
 450                         "EC %d", seb->pnum, seb->sqnum, seb->ec);
 451
 452                 /*
 453                  * Make sure that the logical eraseblocks have different
 454                  * sequence numbers. Otherwise the image is bad.
 455                  *
 456                  * However, if the sequence number is zero, we assume it must
 457                  * be an ancient UBI image from the era when UBI did not have
 458                  * sequence numbers. We still can attach these images, unless
 459                  * there is a need to distinguish between old and new
 460                  * eraseblocks, in which case we'll refuse the image in
 461                  * 'compare_lebs()'. In other words, we attach old clean
 462                  * images, but refuse attaching old images with duplicated
 463                  * logical eraseblocks because there was an unclean reboot.
 464                  */
 465                 if (seb->sqnum == sqnum && sqnum != 0) {
 466                         ubi_err("two LEBs with same sequence number %llu",
 467                                 sqnum);
 468                         ubi_dbg_dump_seb(seb, 0);
 469                         ubi_dbg_dump_vid_hdr(vid_hdr);
 470                         return -EINVAL;
 471                 }
 472
 473                 /*
 474                  * Now we have to drop the older one and preserve the newer
 475                  * one.
 476                  */
 477                 cmp_res = compare_lebs(ubi, seb, pnum, vid_hdr);
 478                 if (cmp_res < 0)
 479                         return cmp_res;
 480
 481                 if (cmp_res & 1) {
 482                         /*
 483                          * This logical eraseblock is newer than the one
 484                          * found earlier.
 485                          */
 486                         err = validate_vid_hdr(vid_hdr, sv, pnum);
 487                         if (err)
 488                                 return err;
 489
 490                         if (cmp_res & 4)
 491                                 err = add_corrupted(si, seb->pnum, seb->ec);
 492                         else
 493                                 err = add_to_list(si, seb->pnum, seb->ec,
 494                                                   &si->erase);
 495                         if (err)
 496                                 return err;
 497
 498                         seb->ec = ec;
 499                         seb->pnum = pnum;
 500                         seb->scrub = ((cmp_res & 2) || bitflips);
 501                         seb->sqnum = sqnum;
 502
 503                         if (sv->highest_lnum == lnum)
 504                                 sv->last_data_size =
 505                                         be32_to_cpu(vid_hdr->data_size);
 506
 507                         return 0;
 508                 } else {
 509                         /*
 510                          * This logical eraseblock is older than the one found
 511                          * previously.
 512                          */
 513                         if (cmp_res & 4)
 514                                 return add_corrupted(si, pnum, ec);
 515                         else
 516                                 return add_to_list(si, pnum, ec, &si->erase);
 517                 }
 518         }
 519
 520         /*
 521          * We've met this logical eraseblock for the first time, add it to the
 522          * scanning information.
 523          */
 524
 525         err = validate_vid_hdr(vid_hdr, sv, pnum);
 526         if (err)
 527                 return err;
 528
 529         seb = kmalloc(sizeof(struct ubi_scan_leb), GFP_KERNEL);
 530         if (!seb)
 531                 return -ENOMEM;
 532
 533         seb->ec = ec;
 534         seb->pnum = pnum;
 535         seb->lnum = lnum;
 536         seb->sqnum = sqnum;
 537         seb->scrub = bitflips;
 538
 539         if (sv->highest_lnum <= lnum) {
 540                 sv->highest_lnum = lnum;
 541                 sv->last_data_size = be32_to_cpu(vid_hdr->data_size);
 542         }
 543
 544         sv->leb_count += 1;
 545         rb_link_node(&seb->u.rb, parent, p);
 546         rb_insert_color(&seb->u.rb, &sv->root);
 547         si->used_peb_count += 1;
 548         return 0;
 549 }
 550
 551 /**
 552  * ubi_scan_find_sv - find volume in the scanning information.
 553  * @si: scanning information
 554  * @vol_id: the requested volume ID
 555  *
 556  * This function returns a pointer to the volume description or %NULL if there
 557  * are no data about this volume in the scanning information.
 558  */
 559 struct ubi_scan_volume *ubi_scan_find_sv(const struct ubi_scan_info *si,
 560                                          int vol_id)
 561 {
 562         struct ubi_scan_volume *sv;
 563         struct rb_node *p = si->volumes.rb_node;
 564
 565         while (p) {
 566                 sv = rb_entry(p, struct ubi_scan_volume, rb);
 567
 568                 if (vol_id == sv->vol_id)
 569                         return sv;
 570
 571                 if (vol_id > sv->vol_id)
 572                         p = p->rb_left;
 573                 else
 574                         p = p->rb_right;
 575         }
 576
 577         return NULL;
 578 }
 579
 580 /**
 581  * ubi_scan_find_seb - find LEB in the volume scanning information.
 582  * @sv: a pointer to the volume scanning information
 583  * @lnum: the requested logical eraseblock
 584  *
 585  * This function returns a pointer to the scanning logical eraseblock or %NULL
 586  * if there are no data about it in the scanning volume information.
 587  */
 588 struct ubi_scan_leb *ubi_scan_find_seb(const struct ubi_scan_volume *sv,
 589                                        int lnum)
 590 {
 591         struct ubi_scan_leb *seb;
 592         struct rb_node *p = sv->root.rb_node;
 593
 594         while (p) {
 595                 seb = rb_entry(p, struct ubi_scan_leb, u.rb);
 596
 597                 if (lnum == seb->lnum)
 598                         return seb;
 599
 600                 if (lnum > seb->lnum)
 601                         p = p->rb_left;
 602                 else
 603                         p = p->rb_right;
 604         }
 605
 606         return NULL;
 607 }
 608
 609 /**
 610  * ubi_scan_rm_volume - delete scanning information about a volume.
 611  * @si: scanning information
 612  * @sv: the volume scanning information to delete
 613  */
 614 void ubi_scan_rm_volume(struct ubi_scan_info *si, struct ubi_scan_volume *sv)
 615 {
 616         struct rb_node *rb;
 617         struct ubi_scan_leb *seb;
 618
 619         dbg_bld("remove scanning information about volume %d", sv->vol_id);
 620
 621         while ((rb = rb_first(&sv->root))) {
 622                 seb = rb_entry(rb, struct ubi_scan_leb, u.rb);
 623                 rb_erase(&seb->u.rb, &sv->root);
 624                 list_add_tail(&seb->u.list, &si->erase);
 625         }
 626
 627         rb_erase(&sv->rb, &si->volumes);
 628         kfree(sv);
 629         si->vols_found -= 1;
 630 }
 631
 632 /**
 633  * ubi_scan_erase_peb - erase a physical eraseblock.
 634  * @ubi: UBI device description object
 635  * @si: scanning information
 636  * @pnum: physical eraseblock number to erase;
 637  * @ec: erase counter value to write (%UBI_SCAN_UNKNOWN_EC if it is unknown)
 638  *
 639  * This function erases physical eraseblock 'pnum', and writes the erase
 640  * counter header to it. This function should only be used on UBI device
 641  * initialization stages, when the EBA sub-system had not been yet initialized.
 642  * This function returns zero in case of success and a negative error code in
 643  * case of failure.
 644  */
 645 int ubi_scan_erase_peb(struct ubi_device *ubi, const struct ubi_scan_info *si,
 646                        int pnum, int ec)
 647 {
 648         int err;
 649         struct ubi_ec_hdr *ec_hdr;
 650
 651         if ((long long)ec >= UBI_MAX_ERASECOUNTER) {
 652                 /*
 653                  * Erase counter overflow. Upgrade UBI and use 64-bit
 654                  * erase counters internally.
 655                  */
 656                 ubi_err("erase counter overflow at PEB %d, EC %d", pnum, ec);
 657                 return -EINVAL;
 658         }
 659
 660         ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
 661         if (!ec_hdr)
 662                 return -ENOMEM;
 663
 664         ec_hdr->ec = cpu_to_be64(ec);
 665
 666         err = ubi_io_sync_erase(ubi, pnum, 0);
 667         if (err < 0)
 668                 goto out_free;
 669
 670         err = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
 671
 672 out_free:
 673         kfree(ec_hdr);
 674         return err;
 675 }
 676
 677 /**
 678  * ubi_scan_get_free_peb - get a free physical eraseblock.
 679  * @ubi: UBI device description object
 680  * @si: scanning information
 681  *
 682  * This function returns a free physical eraseblock. It is supposed to be
 683  * called on the UBI initialization stages when the wear-leveling sub-system is
 684  * not initialized yet. This function picks a physical eraseblocks from one of
 685  * the lists, writes the EC header if it is needed, and removes it from the
 686  * list.
 687  *
 688  * This function returns scanning physical eraseblock information in case of
 689  * success and an error code in case of failure.
 690  */
 691 struct ubi_scan_leb *ubi_scan_get_free_peb(struct ubi_device *ubi,
 692                                            struct ubi_scan_info *si)
 693 {
 694         int err = 0, i;
 695         struct ubi_scan_leb *seb;
 696
 697         if (!list_empty(&si->free)) {
 698                 seb = list_entry(si->free.next, struct ubi_scan_leb, u.list);
 699                 list_del(&seb->u.list);
 700                 dbg_bld("return free PEB %d, EC %d", seb->pnum, seb->ec);
 701                 return seb;
 702         }
 703
 704         for (i = 0; i < 2; i++) {
 705                 struct list_head *head;
 706                 struct ubi_scan_leb *tmp_seb;
 707
 708                 if (i == 0)
 709                         head = &si->erase;
 710                 else
 711                         head = &si->corr;
 712
 713                 /*
 714                  * We try to erase the first physical eraseblock from the @head
 715                  * list and pick it if we succeed, or try to erase the
 716                  * next one if not. And so forth. We don't want to take care
 717                  * about bad eraseblocks here - they'll be handled later.
 718                  */
 719                 list_for_each_entry_safe(seb, tmp_seb, head, u.list) {
 720                         if (seb->ec == UBI_SCAN_UNKNOWN_EC)
 721                                 seb->ec = si->mean_ec;
 722
 723                         err = ubi_scan_erase_peb(ubi, si, seb->pnum, seb->ec+1);
 724                         if (err)
 725                                 continue;
 726
 727                         seb->ec += 1;
 728                         list_del(&seb->u.list);
 729                         dbg_bld("return PEB %d, EC %d", seb->pnum, seb->ec);
 730                         return seb;
 731                 }
 732         }
 733
 734         ubi_err("no eraseblocks found");
 735         return ERR_PTR(-ENOSPC);
 736 }
 737
 738 /**
 739  * process_eb - read, check UBI headers, and add them to scanning information.
 740  * @ubi: UBI device description object
 741  * @si: scanning information
 742  * @pnum: the physical eraseblock number
 743  *
 744  * This function returns a zero if the physical eraseblock was successfully
 745  * handled and a negative error code in case of failure.
 746  */
 747 static int process_eb(struct ubi_device *ubi, struct ubi_scan_info *si,
 748                       int pnum)
 749 {
 750         long long uninitialized_var(ec);
 751         int err, bitflips = 0, vol_id, ec_err = 0;
 752
 753         dbg_bld("scan PEB %d", pnum);
 754
 755         /* Skip bad physical eraseblocks */
 756         err = ubi_io_is_bad(ubi, pnum);
 757         if (err < 0)
 758                 return err;
 759         else if (err) {
 760                 /*
 761                  * FIXME: this is actually duty of the I/O sub-system to
 762                  * initialize this, but MTD does not provide enough
 763                  * information.
 764                  */
 765                 si->bad_peb_count += 1;
 766                 return 0;
 767         }
 768
 769         err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
 770         if (err < 0)
 771                 return err;
 772         switch (err) {
 773         case 0:
 774                 break;
 775         case UBI_IO_BITFLIPS:
 776                 bitflips = 1;
 777                 break;
 778         case UBI_IO_FF:
 779         case UBI_IO_FF_BITFLIPS:
 780                 return add_to_list(si, pnum, UBI_SCAN_UNKNOWN_EC, &si->erase);
 781         case UBI_IO_BAD_HDR_EBADMSG:
 782                 si->read_err_count += 1;
 783         case UBI_IO_BAD_HDR:
 784                 /*
 785                  * We have to also look at the VID header, possibly it is not
 786                  * corrupted. Set %bitflips flag in order to make this PEB be
 787                  * moved and EC be re-created.
 788                  */
 789                 ec_err = err;
 790                 ec = UBI_SCAN_UNKNOWN_EC;
 791                 bitflips = 1;
 792                 break;
 793         default:
 794                 ubi_err("'ubi_io_read_ec_hdr()' returned unknown code %d", err);
 795                 return -EINVAL;
 796         }
 797
 798         if (!ec_err) {
 799                 int image_seq;
 800
 801                 /* Make sure UBI version is OK */
 802                 if (ech->version != UBI_VERSION) {
 803                         ubi_err("this UBI version is %d, image version is %d",
 804                                 UBI_VERSION, (int)ech->version);
 805                         return -EINVAL;
 806                 }
 807
 808                 ec = be64_to_cpu(ech->ec);
 809                 if (ec > UBI_MAX_ERASECOUNTER) {
 810                         /*
 811                          * Erase counter overflow. The EC headers have 64 bits
 812                          * reserved, but we anyway make use of only 31 bit
 813                          * values, as this seems to be enough for any existing
 814                          * flash. Upgrade UBI and use 64-bit erase counters
 815                          * internally.
 816                          */
 817                         ubi_err("erase counter overflow, max is %d",
 818                                 UBI_MAX_ERASECOUNTER);
 819                         ubi_dbg_dump_ec_hdr(ech);
 820                         return -EINVAL;
 821                 }
 822
 823                 /*
 824                  * Make sure that all PEBs have the same image sequence number.
 825                  * This allows us to detect situations when users flash UBI
 826                  * images incorrectly, so that the flash has the new UBI image
 827                  * and leftovers from the old one. This feature was added
 828                  * relatively recently, and the sequence number was always
 829                  * zero, because old UBI implementations always set it to zero.
 830                  * For this reasons, we do not panic if some PEBs have zero
 831                  * sequence number, while other PEBs have non-zero sequence
 832                  * number.
 833                  */
 834                 image_seq = be32_to_cpu(ech->image_seq);
 835                 if (!ubi->image_seq && image_seq)
 836                         ubi->image_seq = image_seq;
 837                 if (ubi->image_seq && image_seq &&
 838                     ubi->image_seq != image_seq) {
 839                         ubi_err("bad image sequence number %d in PEB %d, "
 840                                 "expected %d", image_seq, pnum, ubi->image_seq);
 841                         ubi_dbg_dump_ec_hdr(ech);
 842                         return -EINVAL;
 843                 }
 844         }
 845
 846         /* OK, we've done with the EC header, let's look at the VID header */
 847
 848         err = ubi_io_read_vid_hdr(ubi, pnum, vidh, 0);
 849         if (err < 0)
 850                 return err;
 851         switch (err) {
 852         case 0:
 853                 break;
 854         case UBI_IO_BITFLIPS:
 855                 bitflips = 1;
 856                 break;
 857         case UBI_IO_BAD_HDR_EBADMSG:
 858                 si->read_err_count += 1;
 859         case UBI_IO_BAD_HDR:
 860         case UBI_IO_FF_BITFLIPS:
 861                 err = add_corrupted(si, pnum, ec);
 862                 if (err)
 863                         return err;
 864                 goto adjust_mean_ec;
 865         case UBI_IO_FF:
 866                 if (ec_err)
 867                         err = add_corrupted(si, pnum, ec);
 868                 else
 869                         err = add_to_list(si, pnum, ec, &si->free);
 870                 if (err)
 871                         return err;
 872                 goto adjust_mean_ec;
 873         default:
 874                 ubi_err("'ubi_io_read_vid_hdr()' returned unknown code %d",
 875                         err);
 876                 return -EINVAL;
 877         }
 878
 879         vol_id = be32_to_cpu(vidh->vol_id);
 880         if (vol_id > UBI_MAX_VOLUMES && vol_id != UBI_LAYOUT_VOLUME_ID) {
 881                 int lnum = be32_to_cpu(vidh->lnum);
 882
 883                 /* Unsupported internal volume */
 884                 switch (vidh->compat) {
 885                 case UBI_COMPAT_DELETE:
 886                         ubi_msg("\"delete\" compatible internal volume %d:%d"
 887                                 " found, will remove it", vol_id, lnum);
 888                         err = add_to_list(si, pnum, ec, &si->erase);
 889                         if (err)
 890                                 return err;
 891                         return 0;
 892
 893                 case UBI_COMPAT_RO:
 894                         ubi_msg("read-only compatible internal volume %d:%d"
 895                                 " found, switch to read-only mode",
 896                                 vol_id, lnum);
 897                         ubi->ro_mode = 1;
 898                         break;
 899
 900                 case UBI_COMPAT_PRESERVE:
 901                         ubi_msg("\"preserve\" compatible internal volume %d:%d"
 902                                 " found", vol_id, lnum);
 903                         err = add_to_list(si, pnum, ec, &si->alien);
 904                         if (err)
 905                                 return err;
 906                         return 0;
 907
 908                 case UBI_COMPAT_REJECT:
 909                         ubi_err("incompatible internal volume %d:%d found",
 910                                 vol_id, lnum);
 911                         return -EINVAL;
 912                 }
 913         }
 914
 915         if (ec_err)
 916                 ubi_warn("valid VID header but corrupted EC header at PEB %d",
 917                          pnum);
 918         err = ubi_scan_add_used(ubi, si, pnum, ec, vidh, bitflips);
 919         if (err)
 920                 return err;
 921
 922 adjust_mean_ec:
 923         if (!ec_err) {
 924                 si->ec_sum += ec;
 925                 si->ec_count += 1;
 926                 if (ec > si->max_ec)
 927                         si->max_ec = ec;
 928                 if (ec < si->min_ec)
 929                         si->min_ec = ec;
 930         }
 931
 932         return 0;
 933 }
 934
 935 /**
 936  * check_what_we_have - check what PEB were found by scanning.
 937  * @ubi: UBI device description object
 938  * @si: scanning information
 939  *
 940  * This is a helper function which takes a look what PEBs were found by
 941  * scanning, and decides whether the flash is empty and should be formatted and
 942  * whether there are too many corrupted PEBs and we should not attach this
 943  * MTD device. Returns zero if we should proceed with attaching the MTD device,
 944  * and %-EINVAL if we should not.
 945  */
 946 static int check_what_we_have(struct ubi_device *ubi, struct ubi_scan_info *si)
 947 {
 948         struct ubi_scan_leb *seb;
 949         int max_corr;
 950
 951         max_corr = ubi->peb_count - si->bad_peb_count - si->alien_peb_count;
 952         max_corr = max_corr / 20 ?: 8;
 953
 954         /*
 955          * Few corrupted PEBs are not a problem and may be just a result of
 956          * unclean reboots. However, many of them may indicate some problems
 957          * with the flash HW or driver.
 958          */
 959         if (si->corr_peb_count >= 8) {
 960                 ubi_warn("%d PEBs are corrupted", si->corr_peb_count);
 961                 printk(KERN_WARNING "corrupted PEBs are:");
 962                 list_for_each_entry(seb, &si->corr, u.list)
 963                         printk(KERN_CONT " %d", seb->pnum);
 964                 printk(KERN_CONT "\n");
 965
 966                 /*
 967                  * If too many PEBs are corrupted, we refuse attaching,
 968                  * otherwise, only print a warning.
 969                  */
 970                 if (si->corr_peb_count >= max_corr) {
 971                         ubi_err("too many corrupted PEBs, refusing this device");
 972                         return -EINVAL;
 973                 }
 974         }
 975
 976         if (si->free_peb_count + si->used_peb_count +
 977             si->alien_peb_count == 0) {
 978                 /* No UBI-formatted eraseblocks were found */
 979                 if (si->corr_peb_count == si->read_err_count &&
 980                     si->corr_peb_count < 8) {
 981                         /* No or just few corrupted PEBs, and all of them had a
 982                          * read error. We assume that those are bad PEBs, which
 983                          * were just not marked as bad so far.
 984                          *
 985                          * This piece of code basically tries to distinguish
 986                          * between the following 2 situations:
 987                          *
 988                          * 1. Flash is empty, but there are few bad PEBs, which
 989                          *    are not marked as bad so far, and which were read
 990                          *    with error. We want to go ahead and format this
 991                          *    flash. While formating, the faulty PEBs will
 992                          *    probably be marked as bad.
 993                          *
 994                          * 2. Flash probably contains non-UBI data and we do
 995                          * not want to format it and destroy possibly needed
 996                          * data (e.g., consider the case when the bootloader
 997                          * MTD partition was accidentally fed to UBI).
 998                          */
 999                         si->is_empty = 1;
1000                         ubi_msg("empty MTD device detected");
1001                         get_random_bytes(&ubi->image_seq, sizeof(ubi->image_seq));
1002                 } else {
1003                         ubi_err("MTD device possibly contains non-UBI data, "
1004                                 "refusing it");
1005                         return -EINVAL;
1006                 }
1007         }
1008
1009         if (si->corr_peb_count > 0)
1010                 ubi_msg("corrupted PEBs will be formatted");
1011         return 0;
1012 }
1013
1014 /**
1015  * ubi_scan - scan an MTD device.
1016  * @ubi: UBI device description object
1017  *
1018  * This function does full scanning of an MTD device and returns complete
1019  * information about it. In case of failure, an error code is returned.
1020  */
1021 struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
1022 {
1023         int err, pnum;
1024         struct rb_node *rb1, *rb2;
1025         struct ubi_scan_volume *sv;
1026         struct ubi_scan_leb *seb;
1027         struct ubi_scan_info *si;
1028
1029         si = kzalloc(sizeof(struct ubi_scan_info), GFP_KERNEL);
1030         if (!si)
1031                 return ERR_PTR(-ENOMEM);
1032
1033         INIT_LIST_HEAD(&si->corr);
1034         INIT_LIST_HEAD(&si->free);
1035         INIT_LIST_HEAD(&si->erase);
1036         INIT_LIST_HEAD(&si->alien);
1037         si->volumes = RB_ROOT;
1038
1039         err = -ENOMEM;
1040         ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1041         if (!ech)
1042                 goto out_si;
1043
1044         vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
1045         if (!vidh)
1046                 goto out_ech;
1047
1048         for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1049                 cond_resched();
1050
1051                 dbg_gen("process PEB %d", pnum);
1052                 err = process_eb(ubi, si, pnum);
1053                 if (err < 0)
1054                         goto out_vidh;
1055         }
1056
1057         dbg_msg("scanning is finished");
1058
1059         /* Calculate mean erase counter */
1060         if (si->ec_count)
1061                 si->mean_ec = div_u64(si->ec_sum, si->ec_count);
1062
1063         err = check_what_we_have(ubi, si);
1064         if (err)
1065                 goto out_vidh;
1066
1067         /*
1068          * In case of unknown erase counter we use the mean erase counter
1069          * value.
1070          */
1071         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1072                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1073                         if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1074                                 seb->ec = si->mean_ec;
1075         }
1076
1077         list_for_each_entry(seb, &si->free, u.list) {
1078                 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1079                         seb->ec = si->mean_ec;
1080         }
1081
1082         list_for_each_entry(seb, &si->corr, u.list)
1083                 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1084                         seb->ec = si->mean_ec;
1085
1086         list_for_each_entry(seb, &si->erase, u.list)
1087                 if (seb->ec == UBI_SCAN_UNKNOWN_EC)
1088                         seb->ec = si->mean_ec;
1089
1090         err = paranoid_check_si(ubi, si);
1091         if (err)
1092                 goto out_vidh;
1093
1094         ubi_free_vid_hdr(ubi, vidh);
1095         kfree(ech);
1096
1097         return si;
1098
1099 out_vidh:
1100         ubi_free_vid_hdr(ubi, vidh);
1101 out_ech:
1102         kfree(ech);
1103 out_si:
1104         ubi_scan_destroy_si(si);
1105         return ERR_PTR(err);
1106 }
1107
1108 /**
1109  * destroy_sv - free the scanning volume information
1110  * @sv: scanning volume information
1111  *
1112  * This function destroys the volume RB-tree (@sv->root) and the scanning
1113  * volume information.
1114  */
1115 static void destroy_sv(struct ubi_scan_volume *sv)
1116 {
1117         struct ubi_scan_leb *seb;
1118         struct rb_node *this = sv->root.rb_node;
1119
1120         while (this) {
1121                 if (this->rb_left)
1122                         this = this->rb_left;
1123                 else if (this->rb_right)
1124                         this = this->rb_right;
1125                 else {
1126                         seb = rb_entry(this, struct ubi_scan_leb, u.rb);
1127                         this = rb_parent(this);
1128                         if (this) {
1129                                 if (this->rb_left == &seb->u.rb)
1130                                         this->rb_left = NULL;
1131                                 else
1132                                         this->rb_right = NULL;
1133                         }
1134
1135                         kfree(seb);
1136                 }
1137         }
1138         kfree(sv);
1139 }
1140
1141 /**
1142  * ubi_scan_destroy_si - destroy scanning information.
1143  * @si: scanning information
1144  */
1145 void ubi_scan_destroy_si(struct ubi_scan_info *si)
1146 {
1147         struct ubi_scan_leb *seb, *seb_tmp;
1148         struct ubi_scan_volume *sv;
1149         struct rb_node *rb;
1150
1151         list_for_each_entry_safe(seb, seb_tmp, &si->alien, u.list) {
1152                 list_del(&seb->u.list);
1153                 kfree(seb);
1154         }
1155         list_for_each_entry_safe(seb, seb_tmp, &si->erase, u.list) {
1156                 list_del(&seb->u.list);
1157                 kfree(seb);
1158         }
1159         list_for_each_entry_safe(seb, seb_tmp, &si->corr, u.list) {
1160                 list_del(&seb->u.list);
1161                 kfree(seb);
1162         }
1163         list_for_each_entry_safe(seb, seb_tmp, &si->free, u.list) {
1164                 list_del(&seb->u.list);
1165                 kfree(seb);
1166         }
1167
1168         /* Destroy the volume RB-tree */
1169         rb = si->volumes.rb_node;
1170         while (rb) {
1171                 if (rb->rb_left)
1172                         rb = rb->rb_left;
1173                 else if (rb->rb_right)
1174                         rb = rb->rb_right;
1175                 else {
1176                         sv = rb_entry(rb, struct ubi_scan_volume, rb);
1177
1178                         rb = rb_parent(rb);
1179                         if (rb) {
1180                                 if (rb->rb_left == &sv->rb)
1181                                         rb->rb_left = NULL;
1182                                 else
1183                                         rb->rb_right = NULL;
1184                         }
1185
1186                         destroy_sv(sv);
1187                 }
1188         }
1189
1190         kfree(si);
1191 }
1192
1193 #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
1194
1195 /**
1196  * paranoid_check_si - check the scanning information.
1197  * @ubi: UBI device description object
1198  * @si: scanning information
1199  *
1200  * This function returns zero if the scanning information is all right, and a
1201  * negative error code if not or if an error occurred.
1202  */
1203 static int paranoid_check_si(struct ubi_device *ubi, struct ubi_scan_info *si)
1204 {
1205         int pnum, err, vols_found = 0;
1206         struct rb_node *rb1, *rb2;
1207         struct ubi_scan_volume *sv;
1208         struct ubi_scan_leb *seb, *last_seb;
1209         uint8_t *buf;
1210
1211         /*
1212          * At first, check that scanning information is OK.
1213          */
1214         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1215                 int leb_count = 0;
1216
1217                 cond_resched();
1218
1219                 vols_found += 1;
1220
1221                 if (si->is_empty) {
1222                         ubi_err("bad is_empty flag");
1223                         goto bad_sv;
1224                 }
1225
1226                 if (sv->vol_id < 0 || sv->highest_lnum < 0 ||
1227                     sv->leb_count < 0 || sv->vol_type < 0 || sv->used_ebs < 0 ||
1228                     sv->data_pad < 0 || sv->last_data_size < 0) {
1229                         ubi_err("negative values");
1230                         goto bad_sv;
1231                 }
1232
1233                 if (sv->vol_id >= UBI_MAX_VOLUMES &&
1234                     sv->vol_id < UBI_INTERNAL_VOL_START) {
1235                         ubi_err("bad vol_id");
1236                         goto bad_sv;
1237                 }
1238
1239                 if (sv->vol_id > si->highest_vol_id) {
1240                         ubi_err("highest_vol_id is %d, but vol_id %d is there",
1241                                 si->highest_vol_id, sv->vol_id);
1242                         goto out;
1243                 }
1244
1245                 if (sv->vol_type != UBI_DYNAMIC_VOLUME &&
1246                     sv->vol_type != UBI_STATIC_VOLUME) {
1247                         ubi_err("bad vol_type");
1248                         goto bad_sv;
1249                 }
1250
1251                 if (sv->data_pad > ubi->leb_size / 2) {
1252                         ubi_err("bad data_pad");
1253                         goto bad_sv;
1254                 }
1255
1256                 last_seb = NULL;
1257                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1258                         cond_resched();
1259
1260                         last_seb = seb;
1261                         leb_count += 1;
1262
1263                         if (seb->pnum < 0 || seb->ec < 0) {
1264                                 ubi_err("negative values");
1265                                 goto bad_seb;
1266                         }
1267
1268                         if (seb->ec < si->min_ec) {
1269                                 ubi_err("bad si->min_ec (%d), %d found",
1270                                         si->min_ec, seb->ec);
1271                                 goto bad_seb;
1272                         }
1273
1274                         if (seb->ec > si->max_ec) {
1275                                 ubi_err("bad si->max_ec (%d), %d found",
1276                                         si->max_ec, seb->ec);
1277                                 goto bad_seb;
1278                         }
1279
1280                         if (seb->pnum >= ubi->peb_count) {
1281                                 ubi_err("too high PEB number %d, total PEBs %d",
1282                                         seb->pnum, ubi->peb_count);
1283                                 goto bad_seb;
1284                         }
1285
1286                         if (sv->vol_type == UBI_STATIC_VOLUME) {
1287                                 if (seb->lnum >= sv->used_ebs) {
1288                                         ubi_err("bad lnum or used_ebs");
1289                                         goto bad_seb;
1290                                 }
1291                         } else {
1292                                 if (sv->used_ebs != 0) {
1293                                         ubi_err("non-zero used_ebs");
1294                                         goto bad_seb;
1295                                 }
1296                         }
1297
1298                         if (seb->lnum > sv->highest_lnum) {
1299                                 ubi_err("incorrect highest_lnum or lnum");
1300                                 goto bad_seb;
1301                         }
1302                 }
1303
1304                 if (sv->leb_count != leb_count) {
1305                         ubi_err("bad leb_count, %d objects in the tree",
1306                                 leb_count);
1307                         goto bad_sv;
1308                 }
1309
1310                 if (!last_seb)
1311                         continue;
1312
1313                 seb = last_seb;
1314
1315                 if (seb->lnum != sv->highest_lnum) {
1316                         ubi_err("bad highest_lnum");
1317                         goto bad_seb;
1318                 }
1319         }
1320
1321         if (vols_found != si->vols_found) {
1322                 ubi_err("bad si->vols_found %d, should be %d",
1323                         si->vols_found, vols_found);
1324                 goto out;
1325         }
1326
1327         /* Check that scanning information is correct */
1328         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
1329                 last_seb = NULL;
1330                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
1331                         int vol_type;
1332
1333                         cond_resched();
1334
1335                         last_seb = seb;
1336
1337                         err = ubi_io_read_vid_hdr(ubi, seb->pnum, vidh, 1);
1338                         if (err && err != UBI_IO_BITFLIPS) {
1339                                 ubi_err("VID header is not OK (%d)", err);
1340                                 if (err > 0)
1341                                         err = -EIO;
1342                                 return err;
1343                         }
1344
1345                         vol_type = vidh->vol_type == UBI_VID_DYNAMIC ?
1346                                    UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
1347                         if (sv->vol_type != vol_type) {
1348                                 ubi_err("bad vol_type");
1349                                 goto bad_vid_hdr;
1350                         }
1351
1352                         if (seb->sqnum != be64_to_cpu(vidh->sqnum)) {
1353                                 ubi_err("bad sqnum %llu", seb->sqnum);
1354                                 goto bad_vid_hdr;
1355                         }
1356
1357                         if (sv->vol_id != be32_to_cpu(vidh->vol_id)) {
1358                                 ubi_err("bad vol_id %d", sv->vol_id);
1359                                 goto bad_vid_hdr;
1360                         }
1361
1362                         if (sv->compat != vidh->compat) {
1363                                 ubi_err("bad compat %d", vidh->compat);
1364                                 goto bad_vid_hdr;
1365                         }
1366
1367                         if (seb->lnum != be32_to_cpu(vidh->lnum)) {
1368                                 ubi_err("bad lnum %d", seb->lnum);
1369                                 goto bad_vid_hdr;
1370                         }
1371
1372                         if (sv->used_ebs != be32_to_cpu(vidh->used_ebs)) {
1373                                 ubi_err("bad used_ebs %d", sv->used_ebs);
1374                                 goto bad_vid_hdr;
1375                         }
1376
1377                         if (sv->data_pad != be32_to_cpu(vidh->data_pad)) {
1378                                 ubi_err("bad data_pad %d", sv->data_pad);
1379                                 goto bad_vid_hdr;
1380                         }
1381                 }
1382
1383                 if (!last_seb)
1384                         continue;
1385
1386                 if (sv->highest_lnum != be32_to_cpu(vidh->lnum)) {
1387                         ubi_err("bad highest_lnum %d", sv->highest_lnum);
1388                         goto bad_vid_hdr;
1389                 }
1390
1391                 if (sv->last_data_size != be32_to_cpu(vidh->data_size)) {
1392                         ubi_err("bad last_data_size %d", sv->last_data_size);
1393                         goto bad_vid_hdr;
1394                 }
1395         }
1396
1397         /*
1398          * Make sure that all the physical eraseblocks are in one of the lists
1399          * or trees.
1400          */
1401         buf = kzalloc(ubi->peb_count, GFP_KERNEL);
1402         if (!buf)
1403                 return -ENOMEM;
1404
1405         for (pnum = 0; pnum < ubi->peb_count; pnum++) {
1406                 err = ubi_io_is_bad(ubi, pnum);
1407                 if (err < 0) {
1408                         kfree(buf);
1409                         return err;
1410                 } else if (err)
1411                         buf[pnum] = 1;
1412         }
1413
1414         ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb)
1415                 ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb)
1416                         buf[seb->pnum] = 1;
1417
1418         list_for_each_entry(seb, &si->free, u.list)
1419                 buf[seb->pnum] = 1;
1420
1421         list_for_each_entry(seb, &si->corr, u.list)
1422                 buf[seb->pnum] = 1;
1423
1424         list_for_each_entry(seb, &si->erase, u.list)
1425                 buf[seb->pnum] = 1;
1426
1427         list_for_each_entry(seb, &si->alien, u.list)
1428                 buf[seb->pnum] = 1;
1429
1430         err = 0;
1431         for (pnum = 0; pnum < ubi->peb_count; pnum++)
1432                 if (!buf[pnum]) {
1433                         ubi_err("PEB %d is not referred", pnum);
1434                         err = 1;
1435                 }
1436
1437         kfree(buf);
1438         if (err)
1439                 goto out;
1440         return 0;
1441
1442 bad_seb:
1443         ubi_err("bad scanning information about LEB %d", seb->lnum);
1444         ubi_dbg_dump_seb(seb, 0);
1445         ubi_dbg_dump_sv(sv);
1446         goto out;
1447
1448 bad_sv:
1449         ubi_err("bad scanning information about volume %d", sv->vol_id);
1450         ubi_dbg_dump_sv(sv);
1451         goto out;
1452
1453 bad_vid_hdr:
1454         ubi_err("bad scanning information about volume %d", sv->vol_id);
1455         ubi_dbg_dump_sv(sv);
1456         ubi_dbg_dump_vid_hdr(vidh);
1457
1458 out:
1459         ubi_dbg_dump_stack();
1460         return -EINVAL;
1461 }
1462
1463 #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */