linux/fs/ubifs/lpt.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file is part of UBIFS.
   4 *
   5 * Copyright (C) 2006-2008 Nokia Corporation.
   6 *
   7 * Authors: Adrian Hunter
   8 *          Artem Bityutskiy (Битюцкий Артём)
   9 */
  10
  11/*
  12 * This file implements the LEB properties tree (LPT) area. The LPT area
  13 * contains the LEB properties tree, a table of LPT area eraseblocks (ltab), and
  14 * (for the "big" model) a table of saved LEB numbers (lsave). The LPT area sits
  15 * between the log and the orphan area.
  16 *
  17 * The LPT area is like a miniature self-contained file system. It is required
  18 * that it never runs out of space, is fast to access and update, and scales
  19 * logarithmically. The LEB properties tree is implemented as a wandering tree
  20 * much like the TNC, and the LPT area has its own garbage collection.
  21 *
  22 * The LPT has two slightly different forms called the "small model" and the
  23 * "big model". The small model is used when the entire LEB properties table
  24 * can be written into a single eraseblock. In that case, garbage collection
  25 * consists of just writing the whole table, which therefore makes all other
  26 * eraseblocks reusable. In the case of the big model, dirty eraseblocks are
  27 * selected for garbage collection, which consists of marking the clean nodes in
  28 * that LEB as dirty, and then only the dirty nodes are written out. Also, in
  29 * the case of the big model, a table of LEB numbers is saved so that the entire
  30 * LPT does not to be scanned looking for empty eraseblocks when UBIFS is first
  31 * mounted.
  32 */
  33
  34#include "ubifs.h"
  35#include <linux/crc16.h>
  36#include <linux/math64.h>
  37#include <linux/slab.h>
  38
  39/**
  40 * do_calc_lpt_geom - calculate sizes for the LPT area.
  41 * @c: the UBIFS file-system description object
  42 *
  43 * Calculate the sizes of LPT bit fields, nodes, and tree, based on the
  44 * properties of the flash and whether LPT is "big" (c->big_lpt).
  45 */
  46static void do_calc_lpt_geom(struct ubifs_info *c)
  47{
  48        int i, n, bits, per_leb_wastage, max_pnode_cnt;
  49        long long sz, tot_wastage;
  50
  51        n = c->main_lebs + c->max_leb_cnt - c->leb_cnt;
  52        max_pnode_cnt = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
  53
  54        c->lpt_hght = 1;
  55        n = UBIFS_LPT_FANOUT;
  56        while (n < max_pnode_cnt) {
  57                c->lpt_hght += 1;
  58                n <<= UBIFS_LPT_FANOUT_SHIFT;
  59        }
  60
  61        c->pnode_cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
  62
  63        n = DIV_ROUND_UP(c->pnode_cnt, UBIFS_LPT_FANOUT);
  64        c->nnode_cnt = n;
  65        for (i = 1; i < c->lpt_hght; i++) {
  66                n = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
  67                c->nnode_cnt += n;
  68        }
  69
  70        c->space_bits = fls(c->leb_size) - 3;
  71        c->lpt_lnum_bits = fls(c->lpt_lebs);
  72        c->lpt_offs_bits = fls(c->leb_size - 1);
  73        c->lpt_spc_bits = fls(c->leb_size);
  74
  75        n = DIV_ROUND_UP(c->max_leb_cnt, UBIFS_LPT_FANOUT);
  76        c->pcnt_bits = fls(n - 1);
  77
  78        c->lnum_bits = fls(c->max_leb_cnt - 1);
  79
  80        bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
  81               (c->big_lpt ? c->pcnt_bits : 0) +
  82               (c->space_bits * 2 + 1) * UBIFS_LPT_FANOUT;
  83        c->pnode_sz = (bits + 7) / 8;
  84
  85        bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
  86               (c->big_lpt ? c->pcnt_bits : 0) +
  87               (c->lpt_lnum_bits + c->lpt_offs_bits) * UBIFS_LPT_FANOUT;
  88        c->nnode_sz = (bits + 7) / 8;
  89
  90        bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
  91               c->lpt_lebs * c->lpt_spc_bits * 2;
  92        c->ltab_sz = (bits + 7) / 8;
  93
  94        bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
  95               c->lnum_bits * c->lsave_cnt;
  96        c->lsave_sz = (bits + 7) / 8;
  97
  98        /* Calculate the minimum LPT size */
  99        c->lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
 100        c->lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
 101        c->lpt_sz += c->ltab_sz;
 102        if (c->big_lpt)
 103                c->lpt_sz += c->lsave_sz;
 104
 105        /* Add wastage */
 106        sz = c->lpt_sz;
 107        per_leb_wastage = max_t(int, c->pnode_sz, c->nnode_sz);
 108        sz += per_leb_wastage;
 109        tot_wastage = per_leb_wastage;
 110        while (sz > c->leb_size) {
 111                sz += per_leb_wastage;
 112                sz -= c->leb_size;
 113                tot_wastage += per_leb_wastage;
 114        }
 115        tot_wastage += ALIGN(sz, c->min_io_size) - sz;
 116        c->lpt_sz += tot_wastage;
 117}
 118
 119/**
 120 * ubifs_calc_lpt_geom - calculate and check sizes for the LPT area.
 121 * @c: the UBIFS file-system description object
 122 *
 123 * This function returns %0 on success and a negative error code on failure.
 124 */
 125int ubifs_calc_lpt_geom(struct ubifs_info *c)
 126{
 127        int lebs_needed;
 128        long long sz;
 129
 130        do_calc_lpt_geom(c);
 131
 132        /* Verify that lpt_lebs is big enough */
 133        sz = c->lpt_sz * 2; /* Must have at least 2 times the size */
 134        lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
 135        if (lebs_needed > c->lpt_lebs) {
 136                ubifs_err(c, "too few LPT LEBs");
 137                return -EINVAL;
 138        }
 139
 140        /* Verify that ltab fits in a single LEB (since ltab is a single node */
 141        if (c->ltab_sz > c->leb_size) {
 142                ubifs_err(c, "LPT ltab too big");
 143                return -EINVAL;
 144        }
 145
 146        c->check_lpt_free = c->big_lpt;
 147        return 0;
 148}
 149
 150/**
 151 * calc_dflt_lpt_geom - calculate default LPT geometry.
 152 * @c: the UBIFS file-system description object
 153 * @main_lebs: number of main area LEBs is passed and returned here
 154 * @big_lpt: whether the LPT area is "big" is returned here
 155 *
 156 * The size of the LPT area depends on parameters that themselves are dependent
 157 * on the size of the LPT area. This function, successively recalculates the LPT
 158 * area geometry until the parameters and resultant geometry are consistent.
 159 *
 160 * This function returns %0 on success and a negative error code on failure.
 161 */
 162static int calc_dflt_lpt_geom(struct ubifs_info *c, int *main_lebs,
 163                              int *big_lpt)
 164{
 165        int i, lebs_needed;
 166        long long sz;
 167
 168        /* Start by assuming the minimum number of LPT LEBs */
 169        c->lpt_lebs = UBIFS_MIN_LPT_LEBS;
 170        c->main_lebs = *main_lebs - c->lpt_lebs;
 171        if (c->main_lebs <= 0)
 172                return -EINVAL;
 173
 174        /* And assume we will use the small LPT model */
 175        c->big_lpt = 0;
 176
 177        /*
 178         * Calculate the geometry based on assumptions above and then see if it
 179         * makes sense
 180         */
 181        do_calc_lpt_geom(c);
 182
 183        /* Small LPT model must have lpt_sz < leb_size */
 184        if (c->lpt_sz > c->leb_size) {
 185                /* Nope, so try again using big LPT model */
 186                c->big_lpt = 1;
 187                do_calc_lpt_geom(c);
 188        }
 189
 190        /* Now check there are enough LPT LEBs */
 191        for (i = 0; i < 64 ; i++) {
 192                sz = c->lpt_sz * 4; /* Allow 4 times the size */
 193                lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
 194                if (lebs_needed > c->lpt_lebs) {
 195                        /* Not enough LPT LEBs so try again with more */
 196                        c->lpt_lebs = lebs_needed;
 197                        c->main_lebs = *main_lebs - c->lpt_lebs;
 198                        if (c->main_lebs <= 0)
 199                                return -EINVAL;
 200                        do_calc_lpt_geom(c);
 201                        continue;
 202                }
 203                if (c->ltab_sz > c->leb_size) {
 204                        ubifs_err(c, "LPT ltab too big");
 205                        return -EINVAL;
 206                }
 207                *main_lebs = c->main_lebs;
 208                *big_lpt = c->big_lpt;
 209                return 0;
 210        }
 211        return -EINVAL;
 212}
 213
 214/**
 215 * pack_bits - pack bit fields end-to-end.
 216 * @c: UBIFS file-system description object
 217 * @addr: address at which to pack (passed and next address returned)
 218 * @pos: bit position at which to pack (passed and next position returned)
 219 * @val: value to pack
 220 * @nrbits: number of bits of value to pack (1-32)
 221 */
 222static void pack_bits(const struct ubifs_info *c, uint8_t **addr, int *pos, uint32_t val, int nrbits)
 223{
 224        uint8_t *p = *addr;
 225        int b = *pos;
 226
 227        ubifs_assert(c, nrbits > 0);
 228        ubifs_assert(c, nrbits <= 32);
 229        ubifs_assert(c, *pos >= 0);
 230        ubifs_assert(c, *pos < 8);
 231        ubifs_assert(c, (val >> nrbits) == 0 || nrbits == 32);
 232        if (b) {
 233                *p |= ((uint8_t)val) << b;
 234                nrbits += b;
 235                if (nrbits > 8) {
 236                        *++p = (uint8_t)(val >>= (8 - b));
 237                        if (nrbits > 16) {
 238                                *++p = (uint8_t)(val >>= 8);
 239                                if (nrbits > 24) {
 240                                        *++p = (uint8_t)(val >>= 8);
 241                                        if (nrbits > 32)
 242                                                *++p = (uint8_t)(val >>= 8);
 243                                }
 244                        }
 245                }
 246        } else {
 247                *p = (uint8_t)val;
 248                if (nrbits > 8) {
 249                        *++p = (uint8_t)(val >>= 8);
 250                        if (nrbits > 16) {
 251                                *++p = (uint8_t)(val >>= 8);
 252                                if (nrbits > 24)
 253                                        *++p = (uint8_t)(val >>= 8);
 254                        }
 255                }
 256        }
 257        b = nrbits & 7;
 258        if (b == 0)
 259                p++;
 260        *addr = p;
 261        *pos = b;
 262}
 263
 264/**
 265 * ubifs_unpack_bits - unpack bit fields.
 266 * @c: UBIFS file-system description object
 267 * @addr: address at which to unpack (passed and next address returned)
 268 * @pos: bit position at which to unpack (passed and next position returned)
 269 * @nrbits: number of bits of value to unpack (1-32)
 270 *
 271 * This functions returns the value unpacked.
 272 */
 273uint32_t ubifs_unpack_bits(const struct ubifs_info *c, uint8_t **addr, int *pos, int nrbits)
 274{
 275        const int k = 32 - nrbits;
 276        uint8_t *p = *addr;
 277        int b = *pos;
 278        uint32_t uninitialized_var(val);
 279        const int bytes = (nrbits + b + 7) >> 3;
 280
 281        ubifs_assert(c, nrbits > 0);
 282        ubifs_assert(c, nrbits <= 32);
 283        ubifs_assert(c, *pos >= 0);
 284        ubifs_assert(c, *pos < 8);
 285        if (b) {
 286                switch (bytes) {
 287                case 2:
 288                        val = p[1];
 289                        break;
 290                case 3:
 291                        val = p[1] | ((uint32_t)p[2] << 8);
 292                        break;
 293                case 4:
 294                        val = p[1] | ((uint32_t)p[2] << 8) |
 295                                     ((uint32_t)p[3] << 16);
 296                        break;
 297                case 5:
 298                        val = p[1] | ((uint32_t)p[2] << 8) |
 299                                     ((uint32_t)p[3] << 16) |
 300                                     ((uint32_t)p[4] << 24);
 301                }
 302                val <<= (8 - b);
 303                val |= *p >> b;
 304                nrbits += b;
 305        } else {
 306                switch (bytes) {
 307                case 1:
 308                        val = p[0];
 309                        break;
 310                case 2:
 311                        val = p[0] | ((uint32_t)p[1] << 8);
 312                        break;
 313                case 3:
 314                        val = p[0] | ((uint32_t)p[1] << 8) |
 315                                     ((uint32_t)p[2] << 16);
 316                        break;
 317                case 4:
 318                        val = p[0] | ((uint32_t)p[1] << 8) |
 319                                     ((uint32_t)p[2] << 16) |
 320                                     ((uint32_t)p[3] << 24);
 321                        break;
 322                }
 323        }
 324        val <<= k;
 325        val >>= k;
 326        b = nrbits & 7;
 327        p += nrbits >> 3;
 328        *addr = p;
 329        *pos = b;
 330        ubifs_assert(c, (val >> nrbits) == 0 || nrbits - b == 32);
 331        return val;
 332}
 333
 334/**
 335 * ubifs_pack_pnode - pack all the bit fields of a pnode.
 336 * @c: UBIFS file-system description object
 337 * @buf: buffer into which to pack
 338 * @pnode: pnode to pack
 339 */
 340void ubifs_pack_pnode(struct ubifs_info *c, void *buf,
 341                      struct ubifs_pnode *pnode)
 342{
 343        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
 344        int i, pos = 0;
 345        uint16_t crc;
 346
 347        pack_bits(c, &addr, &pos, UBIFS_LPT_PNODE, UBIFS_LPT_TYPE_BITS);
 348        if (c->big_lpt)
 349                pack_bits(c, &addr, &pos, pnode->num, c->pcnt_bits);
 350        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
 351                pack_bits(c, &addr, &pos, pnode->lprops[i].free >> 3,
 352                          c->space_bits);
 353                pack_bits(c, &addr, &pos, pnode->lprops[i].dirty >> 3,
 354                          c->space_bits);
 355                if (pnode->lprops[i].flags & LPROPS_INDEX)
 356                        pack_bits(c, &addr, &pos, 1, 1);
 357                else
 358                        pack_bits(c, &addr, &pos, 0, 1);
 359        }
 360        crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
 361                    c->pnode_sz - UBIFS_LPT_CRC_BYTES);
 362        addr = buf;
 363        pos = 0;
 364        pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
 365}
 366
 367/**
 368 * ubifs_pack_nnode - pack all the bit fields of a nnode.
 369 * @c: UBIFS file-system description object
 370 * @buf: buffer into which to pack
 371 * @nnode: nnode to pack
 372 */
 373void ubifs_pack_nnode(struct ubifs_info *c, void *buf,
 374                      struct ubifs_nnode *nnode)
 375{
 376        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
 377        int i, pos = 0;
 378        uint16_t crc;
 379
 380        pack_bits(c, &addr, &pos, UBIFS_LPT_NNODE, UBIFS_LPT_TYPE_BITS);
 381        if (c->big_lpt)
 382                pack_bits(c, &addr, &pos, nnode->num, c->pcnt_bits);
 383        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
 384                int lnum = nnode->nbranch[i].lnum;
 385
 386                if (lnum == 0)
 387                        lnum = c->lpt_last + 1;
 388                pack_bits(c, &addr, &pos, lnum - c->lpt_first, c->lpt_lnum_bits);
 389                pack_bits(c, &addr, &pos, nnode->nbranch[i].offs,
 390                          c->lpt_offs_bits);
 391        }
 392        crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
 393                    c->nnode_sz - UBIFS_LPT_CRC_BYTES);
 394        addr = buf;
 395        pos = 0;
 396        pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
 397}
 398
 399/**
 400 * ubifs_pack_ltab - pack the LPT's own lprops table.
 401 * @c: UBIFS file-system description object
 402 * @buf: buffer into which to pack
 403 * @ltab: LPT's own lprops table to pack
 404 */
 405void ubifs_pack_ltab(struct ubifs_info *c, void *buf,
 406                     struct ubifs_lpt_lprops *ltab)
 407{
 408        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
 409        int i, pos = 0;
 410        uint16_t crc;
 411
 412        pack_bits(c, &addr, &pos, UBIFS_LPT_LTAB, UBIFS_LPT_TYPE_BITS);
 413        for (i = 0; i < c->lpt_lebs; i++) {
 414                pack_bits(c, &addr, &pos, ltab[i].free, c->lpt_spc_bits);
 415                pack_bits(c, &addr, &pos, ltab[i].dirty, c->lpt_spc_bits);
 416        }
 417        crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
 418                    c->ltab_sz - UBIFS_LPT_CRC_BYTES);
 419        addr = buf;
 420        pos = 0;
 421        pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
 422}
 423
 424/**
 425 * ubifs_pack_lsave - pack the LPT's save table.
 426 * @c: UBIFS file-system description object
 427 * @buf: buffer into which to pack
 428 * @lsave: LPT's save table to pack
 429 */
 430void ubifs_pack_lsave(struct ubifs_info *c, void *buf, int *lsave)
 431{
 432        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
 433        int i, pos = 0;
 434        uint16_t crc;
 435
 436        pack_bits(c, &addr, &pos, UBIFS_LPT_LSAVE, UBIFS_LPT_TYPE_BITS);
 437        for (i = 0; i < c->lsave_cnt; i++)
 438                pack_bits(c, &addr, &pos, lsave[i], c->lnum_bits);
 439        crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
 440                    c->lsave_sz - UBIFS_LPT_CRC_BYTES);
 441        addr = buf;
 442        pos = 0;
 443        pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
 444}
 445
 446/**
 447 * ubifs_add_lpt_dirt - add dirty space to LPT LEB properties.
 448 * @c: UBIFS file-system description object
 449 * @lnum: LEB number to which to add dirty space
 450 * @dirty: amount of dirty space to add
 451 */
 452void ubifs_add_lpt_dirt(struct ubifs_info *c, int lnum, int dirty)
 453{
 454        if (!dirty || !lnum)
 455                return;
 456        dbg_lp("LEB %d add %d to %d",
 457               lnum, dirty, c->ltab[lnum - c->lpt_first].dirty);
 458        ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
 459        c->ltab[lnum - c->lpt_first].dirty += dirty;
 460}
 461
 462/**
 463 * set_ltab - set LPT LEB properties.
 464 * @c: UBIFS file-system description object
 465 * @lnum: LEB number
 466 * @free: amount of free space
 467 * @dirty: amount of dirty space
 468 */
 469static void set_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
 470{
 471        dbg_lp("LEB %d free %d dirty %d to %d %d",
 472               lnum, c->ltab[lnum - c->lpt_first].free,
 473               c->ltab[lnum - c->lpt_first].dirty, free, dirty);
 474        ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
 475        c->ltab[lnum - c->lpt_first].free = free;
 476        c->ltab[lnum - c->lpt_first].dirty = dirty;
 477}
 478
 479/**
 480 * ubifs_add_nnode_dirt - add dirty space to LPT LEB properties.
 481 * @c: UBIFS file-system description object
 482 * @nnode: nnode for which to add dirt
 483 */
 484void ubifs_add_nnode_dirt(struct ubifs_info *c, struct ubifs_nnode *nnode)
 485{
 486        struct ubifs_nnode *np = nnode->parent;
 487
 488        if (np)
 489                ubifs_add_lpt_dirt(c, np->nbranch[nnode->iip].lnum,
 490                                   c->nnode_sz);
 491        else {
 492                ubifs_add_lpt_dirt(c, c->lpt_lnum, c->nnode_sz);
 493                if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
 494                        c->lpt_drty_flgs |= LTAB_DIRTY;
 495                        ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
 496                }
 497        }
 498}
 499
 500/**
 501 * add_pnode_dirt - add dirty space to LPT LEB properties.
 502 * @c: UBIFS file-system description object
 503 * @pnode: pnode for which to add dirt
 504 */
 505static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
 506{
 507        ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
 508                           c->pnode_sz);
 509}
 510
 511/**
 512 * calc_nnode_num - calculate nnode number.
 513 * @row: the row in the tree (root is zero)
 514 * @col: the column in the row (leftmost is zero)
 515 *
 516 * The nnode number is a number that uniquely identifies a nnode and can be used
 517 * easily to traverse the tree from the root to that nnode.
 518 *
 519 * This function calculates and returns the nnode number for the nnode at @row
 520 * and @col.
 521 */
 522static int calc_nnode_num(int row, int col)
 523{
 524        int num, bits;
 525
 526        num = 1;
 527        while (row--) {
 528                bits = (col & (UBIFS_LPT_FANOUT - 1));
 529                col >>= UBIFS_LPT_FANOUT_SHIFT;
 530                num <<= UBIFS_LPT_FANOUT_SHIFT;
 531                num |= bits;
 532        }
 533        return num;
 534}
 535
 536/**
 537 * calc_nnode_num_from_parent - calculate nnode number.
 538 * @c: UBIFS file-system description object
 539 * @parent: parent nnode
 540 * @iip: index in parent
 541 *
 542 * The nnode number is a number that uniquely identifies a nnode and can be used
 543 * easily to traverse the tree from the root to that nnode.
 544 *
 545 * This function calculates and returns the nnode number based on the parent's
 546 * nnode number and the index in parent.
 547 */
 548static int calc_nnode_num_from_parent(const struct ubifs_info *c,
 549                                      struct ubifs_nnode *parent, int iip)
 550{
 551        int num, shft;
 552
 553        if (!parent)
 554                return 1;
 555        shft = (c->lpt_hght - parent->level) * UBIFS_LPT_FANOUT_SHIFT;
 556        num = parent->num ^ (1 << shft);
 557        num |= (UBIFS_LPT_FANOUT + iip) << shft;
 558        return num;
 559}
 560
 561/**
 562 * calc_pnode_num_from_parent - calculate pnode number.
 563 * @c: UBIFS file-system description object
 564 * @parent: parent nnode
 565 * @iip: index in parent
 566 *
 567 * The pnode number is a number that uniquely identifies a pnode and can be used
 568 * easily to traverse the tree from the root to that pnode.
 569 *
 570 * This function calculates and returns the pnode number based on the parent's
 571 * nnode number and the index in parent.
 572 */
 573static int calc_pnode_num_from_parent(const struct ubifs_info *c,
 574                                      struct ubifs_nnode *parent, int iip)
 575{
 576        int i, n = c->lpt_hght - 1, pnum = parent->num, num = 0;
 577
 578        for (i = 0; i < n; i++) {
 579                num <<= UBIFS_LPT_FANOUT_SHIFT;
 580                num |= pnum & (UBIFS_LPT_FANOUT - 1);
 581                pnum >>= UBIFS_LPT_FANOUT_SHIFT;
 582        }
 583        num <<= UBIFS_LPT_FANOUT_SHIFT;
 584        num |= iip;
 585        return num;
 586}
 587
 588/**
 589 * ubifs_create_dflt_lpt - create default LPT.
 590 * @c: UBIFS file-system description object
 591 * @main_lebs: number of main area LEBs is passed and returned here
 592 * @lpt_first: LEB number of first LPT LEB
 593 * @lpt_lebs: number of LEBs for LPT is passed and returned here
 594 * @big_lpt: use big LPT model is passed and returned here
 595 * @hash: hash of the LPT is returned here
 596 *
 597 * This function returns %0 on success and a negative error code on failure.
 598 */
 599int ubifs_create_dflt_lpt(struct ubifs_info *c, int *main_lebs, int lpt_first,
 600                          int *lpt_lebs, int *big_lpt, u8 *hash)
 601{
 602        int lnum, err = 0, node_sz, iopos, i, j, cnt, len, alen, row;
 603        int blnum, boffs, bsz, bcnt;
 604        struct ubifs_pnode *pnode = NULL;
 605        struct ubifs_nnode *nnode = NULL;
 606        void *buf = NULL, *p;
 607        struct ubifs_lpt_lprops *ltab = NULL;
 608        int *lsave = NULL;
 609        struct shash_desc *desc;
 610
 611        err = calc_dflt_lpt_geom(c, main_lebs, big_lpt);
 612        if (err)
 613                return err;
 614        *lpt_lebs = c->lpt_lebs;
 615
 616        /* Needed by 'ubifs_pack_nnode()' and 'set_ltab()' */
 617        c->lpt_first = lpt_first;
 618        /* Needed by 'set_ltab()' */
 619        c->lpt_last = lpt_first + c->lpt_lebs - 1;
 620        /* Needed by 'ubifs_pack_lsave()' */
 621        c->main_first = c->leb_cnt - *main_lebs;
 622
 623        desc = ubifs_hash_get_desc(c);
 624        if (IS_ERR(desc))
 625                return PTR_ERR(desc);
 626
 627        lsave = kmalloc_array(c->lsave_cnt, sizeof(int), GFP_KERNEL);
 628        pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_KERNEL);
 629        nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_KERNEL);
 630        buf = vmalloc(c->leb_size);
 631        ltab = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
 632                                  c->lpt_lebs));
 633        if (!pnode || !nnode || !buf || !ltab || !lsave) {
 634                err = -ENOMEM;
 635                goto out;
 636        }
 637
 638        ubifs_assert(c, !c->ltab);
 639        c->ltab = ltab; /* Needed by set_ltab */
 640
 641        /* Initialize LPT's own lprops */
 642        for (i = 0; i < c->lpt_lebs; i++) {
 643                ltab[i].free = c->leb_size;
 644                ltab[i].dirty = 0;
 645                ltab[i].tgc = 0;
 646                ltab[i].cmt = 0;
 647        }
 648
 649        lnum = lpt_first;
 650        p = buf;
 651        /* Number of leaf nodes (pnodes) */
 652        cnt = c->pnode_cnt;
 653
 654        /*
 655         * The first pnode contains the LEB properties for the LEBs that contain
 656         * the root inode node and the root index node of the index tree.
 657         */
 658        node_sz = ALIGN(ubifs_idx_node_sz(c, 1), 8);
 659        iopos = ALIGN(node_sz, c->min_io_size);
 660        pnode->lprops[0].free = c->leb_size - iopos;
 661        pnode->lprops[0].dirty = iopos - node_sz;
 662        pnode->lprops[0].flags = LPROPS_INDEX;
 663
 664        node_sz = UBIFS_INO_NODE_SZ;
 665        iopos = ALIGN(node_sz, c->min_io_size);
 666        pnode->lprops[1].free = c->leb_size - iopos;
 667        pnode->lprops[1].dirty = iopos - node_sz;
 668
 669        for (i = 2; i < UBIFS_LPT_FANOUT; i++)
 670                pnode->lprops[i].free = c->leb_size;
 671
 672        /* Add first pnode */
 673        ubifs_pack_pnode(c, p, pnode);
 674        err = ubifs_shash_update(c, desc, p, c->pnode_sz);
 675        if (err)
 676                goto out;
 677
 678        p += c->pnode_sz;
 679        len = c->pnode_sz;
 680        pnode->num += 1;
 681
 682        /* Reset pnode values for remaining pnodes */
 683        pnode->lprops[0].free = c->leb_size;
 684        pnode->lprops[0].dirty = 0;
 685        pnode->lprops[0].flags = 0;
 686
 687        pnode->lprops[1].free = c->leb_size;
 688        pnode->lprops[1].dirty = 0;
 689
 690        /*
 691         * To calculate the internal node branches, we keep information about
 692         * the level below.
 693         */
 694        blnum = lnum; /* LEB number of level below */
 695        boffs = 0; /* Offset of level below */
 696        bcnt = cnt; /* Number of nodes in level below */
 697        bsz = c->pnode_sz; /* Size of nodes in level below */
 698
 699        /* Add all remaining pnodes */
 700        for (i = 1; i < cnt; i++) {
 701                if (len + c->pnode_sz > c->leb_size) {
 702                        alen = ALIGN(len, c->min_io_size);
 703                        set_ltab(c, lnum, c->leb_size - alen, alen - len);
 704                        memset(p, 0xff, alen - len);
 705                        err = ubifs_leb_change(c, lnum++, buf, alen);
 706                        if (err)
 707                                goto out;
 708                        p = buf;
 709                        len = 0;
 710                }
 711                ubifs_pack_pnode(c, p, pnode);
 712                err = ubifs_shash_update(c, desc, p, c->pnode_sz);
 713                if (err)
 714                        goto out;
 715
 716                p += c->pnode_sz;
 717                len += c->pnode_sz;
 718                /*
 719                 * pnodes are simply numbered left to right starting at zero,
 720                 * which means the pnode number can be used easily to traverse
 721                 * down the tree to the corresponding pnode.
 722                 */
 723                pnode->num += 1;
 724        }
 725
 726        row = 0;
 727        for (i = UBIFS_LPT_FANOUT; cnt > i; i <<= UBIFS_LPT_FANOUT_SHIFT)
 728                row += 1;
 729        /* Add all nnodes, one level at a time */
 730        while (1) {
 731                /* Number of internal nodes (nnodes) at next level */
 732                cnt = DIV_ROUND_UP(cnt, UBIFS_LPT_FANOUT);
 733                for (i = 0; i < cnt; i++) {
 734                        if (len + c->nnode_sz > c->leb_size) {
 735                                alen = ALIGN(len, c->min_io_size);
 736                                set_ltab(c, lnum, c->leb_size - alen,
 737                                            alen - len);
 738                                memset(p, 0xff, alen - len);
 739                                err = ubifs_leb_change(c, lnum++, buf, alen);
 740                                if (err)
 741                                        goto out;
 742                                p = buf;
 743                                len = 0;
 744                        }
 745                        /* Only 1 nnode at this level, so it is the root */
 746                        if (cnt == 1) {
 747                                c->lpt_lnum = lnum;
 748                                c->lpt_offs = len;
 749                        }
 750                        /* Set branches to the level below */
 751                        for (j = 0; j < UBIFS_LPT_FANOUT; j++) {
 752                                if (bcnt) {
 753                                        if (boffs + bsz > c->leb_size) {
 754                                                blnum += 1;
 755                                                boffs = 0;
 756                                        }
 757                                        nnode->nbranch[j].lnum = blnum;
 758                                        nnode->nbranch[j].offs = boffs;
 759                                        boffs += bsz;
 760                                        bcnt--;
 761                                } else {
 762                                        nnode->nbranch[j].lnum = 0;
 763                                        nnode->nbranch[j].offs = 0;
 764                                }
 765                        }
 766                        nnode->num = calc_nnode_num(row, i);
 767                        ubifs_pack_nnode(c, p, nnode);
 768                        p += c->nnode_sz;
 769                        len += c->nnode_sz;
 770                }
 771                /* Only 1 nnode at this level, so it is the root */
 772                if (cnt == 1)
 773                        break;
 774                /* Update the information about the level below */
 775                bcnt = cnt;
 776                bsz = c->nnode_sz;
 777                row -= 1;
 778        }
 779
 780        if (*big_lpt) {
 781                /* Need to add LPT's save table */
 782                if (len + c->lsave_sz > c->leb_size) {
 783                        alen = ALIGN(len, c->min_io_size);
 784                        set_ltab(c, lnum, c->leb_size - alen, alen - len);
 785                        memset(p, 0xff, alen - len);
 786                        err = ubifs_leb_change(c, lnum++, buf, alen);
 787                        if (err)
 788                                goto out;
 789                        p = buf;
 790                        len = 0;
 791                }
 792
 793                c->lsave_lnum = lnum;
 794                c->lsave_offs = len;
 795
 796                for (i = 0; i < c->lsave_cnt && i < *main_lebs; i++)
 797                        lsave[i] = c->main_first + i;
 798                for (; i < c->lsave_cnt; i++)
 799                        lsave[i] = c->main_first;
 800
 801                ubifs_pack_lsave(c, p, lsave);
 802                p += c->lsave_sz;
 803                len += c->lsave_sz;
 804        }
 805
 806        /* Need to add LPT's own LEB properties table */
 807        if (len + c->ltab_sz > c->leb_size) {
 808                alen = ALIGN(len, c->min_io_size);
 809                set_ltab(c, lnum, c->leb_size - alen, alen - len);
 810                memset(p, 0xff, alen - len);
 811                err = ubifs_leb_change(c, lnum++, buf, alen);
 812                if (err)
 813                        goto out;
 814                p = buf;
 815                len = 0;
 816        }
 817
 818        c->ltab_lnum = lnum;
 819        c->ltab_offs = len;
 820
 821        /* Update ltab before packing it */
 822        len += c->ltab_sz;
 823        alen = ALIGN(len, c->min_io_size);
 824        set_ltab(c, lnum, c->leb_size - alen, alen - len);
 825
 826        ubifs_pack_ltab(c, p, ltab);
 827        p += c->ltab_sz;
 828
 829        /* Write remaining buffer */
 830        memset(p, 0xff, alen - len);
 831        err = ubifs_leb_change(c, lnum, buf, alen);
 832        if (err)
 833                goto out;
 834
 835        err = ubifs_shash_final(c, desc, hash);
 836        if (err)
 837                goto out;
 838
 839        c->nhead_lnum = lnum;
 840        c->nhead_offs = ALIGN(len, c->min_io_size);
 841
 842        dbg_lp("space_bits %d", c->space_bits);
 843        dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
 844        dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
 845        dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
 846        dbg_lp("pcnt_bits %d", c->pcnt_bits);
 847        dbg_lp("lnum_bits %d", c->lnum_bits);
 848        dbg_lp("pnode_sz %d", c->pnode_sz);
 849        dbg_lp("nnode_sz %d", c->nnode_sz);
 850        dbg_lp("ltab_sz %d", c->ltab_sz);
 851        dbg_lp("lsave_sz %d", c->lsave_sz);
 852        dbg_lp("lsave_cnt %d", c->lsave_cnt);
 853        dbg_lp("lpt_hght %d", c->lpt_hght);
 854        dbg_lp("big_lpt %d", c->big_lpt);
 855        dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
 856        dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
 857        dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
 858        if (c->big_lpt)
 859                dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
 860out:
 861        c->ltab = NULL;
 862        kfree(desc);
 863        kfree(lsave);
 864        vfree(ltab);
 865        vfree(buf);
 866        kfree(nnode);
 867        kfree(pnode);
 868        return err;
 869}
 870
 871/**
 872 * update_cats - add LEB properties of a pnode to LEB category lists and heaps.
 873 * @c: UBIFS file-system description object
 874 * @pnode: pnode
 875 *
 876 * When a pnode is loaded into memory, the LEB properties it contains are added,
 877 * by this function, to the LEB category lists and heaps.
 878 */
 879static void update_cats(struct ubifs_info *c, struct ubifs_pnode *pnode)
 880{
 881        int i;
 882
 883        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
 884                int cat = pnode->lprops[i].flags & LPROPS_CAT_MASK;
 885                int lnum = pnode->lprops[i].lnum;
 886
 887                if (!lnum)
 888                        return;
 889                ubifs_add_to_cat(c, &pnode->lprops[i], cat);
 890        }
 891}
 892
 893/**
 894 * replace_cats - add LEB properties of a pnode to LEB category lists and heaps.
 895 * @c: UBIFS file-system description object
 896 * @old_pnode: pnode copied
 897 * @new_pnode: pnode copy
 898 *
 899 * During commit it is sometimes necessary to copy a pnode
 900 * (see dirty_cow_pnode).  When that happens, references in
 901 * category lists and heaps must be replaced.  This function does that.
 902 */
 903static void replace_cats(struct ubifs_info *c, struct ubifs_pnode *old_pnode,
 904                         struct ubifs_pnode *new_pnode)
 905{
 906        int i;
 907
 908        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
 909                if (!new_pnode->lprops[i].lnum)
 910                        return;
 911                ubifs_replace_cat(c, &old_pnode->lprops[i],
 912                                  &new_pnode->lprops[i]);
 913        }
 914}
 915
 916/**
 917 * check_lpt_crc - check LPT node crc is correct.
 918 * @c: UBIFS file-system description object
 919 * @buf: buffer containing node
 920 * @len: length of node
 921 *
 922 * This function returns %0 on success and a negative error code on failure.
 923 */
 924static int check_lpt_crc(const struct ubifs_info *c, void *buf, int len)
 925{
 926        int pos = 0;
 927        uint8_t *addr = buf;
 928        uint16_t crc, calc_crc;
 929
 930        crc = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_CRC_BITS);
 931        calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
 932                         len - UBIFS_LPT_CRC_BYTES);
 933        if (crc != calc_crc) {
 934                ubifs_err(c, "invalid crc in LPT node: crc %hx calc %hx",
 935                          crc, calc_crc);
 936                dump_stack();
 937                return -EINVAL;
 938        }
 939        return 0;
 940}
 941
 942/**
 943 * check_lpt_type - check LPT node type is correct.
 944 * @c: UBIFS file-system description object
 945 * @addr: address of type bit field is passed and returned updated here
 946 * @pos: position of type bit field is passed and returned updated here
 947 * @type: expected type
 948 *
 949 * This function returns %0 on success and a negative error code on failure.
 950 */
 951static int check_lpt_type(const struct ubifs_info *c, uint8_t **addr,
 952                          int *pos, int type)
 953{
 954        int node_type;
 955
 956        node_type = ubifs_unpack_bits(c, addr, pos, UBIFS_LPT_TYPE_BITS);
 957        if (node_type != type) {
 958                ubifs_err(c, "invalid type (%d) in LPT node type %d",
 959                          node_type, type);
 960                dump_stack();
 961                return -EINVAL;
 962        }
 963        return 0;
 964}
 965
 966/**
 967 * unpack_pnode - unpack a pnode.
 968 * @c: UBIFS file-system description object
 969 * @buf: buffer containing packed pnode to unpack
 970 * @pnode: pnode structure to fill
 971 *
 972 * This function returns %0 on success and a negative error code on failure.
 973 */
 974static int unpack_pnode(const struct ubifs_info *c, void *buf,
 975                        struct ubifs_pnode *pnode)
 976{
 977        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
 978        int i, pos = 0, err;
 979
 980        err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_PNODE);
 981        if (err)
 982                return err;
 983        if (c->big_lpt)
 984                pnode->num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
 985        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
 986                struct ubifs_lprops * const lprops = &pnode->lprops[i];
 987
 988                lprops->free = ubifs_unpack_bits(c, &addr, &pos, c->space_bits);
 989                lprops->free <<= 3;
 990                lprops->dirty = ubifs_unpack_bits(c, &addr, &pos, c->space_bits);
 991                lprops->dirty <<= 3;
 992
 993                if (ubifs_unpack_bits(c, &addr, &pos, 1))
 994                        lprops->flags = LPROPS_INDEX;
 995                else
 996                        lprops->flags = 0;
 997                lprops->flags |= ubifs_categorize_lprops(c, lprops);
 998        }
 999        err = check_lpt_crc(c, buf, c->pnode_sz);
1000        return err;
1001}
1002
1003/**
1004 * ubifs_unpack_nnode - unpack a nnode.
1005 * @c: UBIFS file-system description object
1006 * @buf: buffer containing packed nnode to unpack
1007 * @nnode: nnode structure to fill
1008 *
1009 * This function returns %0 on success and a negative error code on failure.
1010 */
1011int ubifs_unpack_nnode(const struct ubifs_info *c, void *buf,
1012                       struct ubifs_nnode *nnode)
1013{
1014        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1015        int i, pos = 0, err;
1016
1017        err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_NNODE);
1018        if (err)
1019                return err;
1020        if (c->big_lpt)
1021                nnode->num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
1022        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1023                int lnum;
1024
1025                lnum = ubifs_unpack_bits(c, &addr, &pos, c->lpt_lnum_bits) +
1026                       c->lpt_first;
1027                if (lnum == c->lpt_last + 1)
1028                        lnum = 0;
1029                nnode->nbranch[i].lnum = lnum;
1030                nnode->nbranch[i].offs = ubifs_unpack_bits(c, &addr, &pos,
1031                                                     c->lpt_offs_bits);
1032        }
1033        err = check_lpt_crc(c, buf, c->nnode_sz);
1034        return err;
1035}
1036
1037/**
1038 * unpack_ltab - unpack the LPT's own lprops table.
1039 * @c: UBIFS file-system description object
1040 * @buf: buffer from which to unpack
1041 *
1042 * This function returns %0 on success and a negative error code on failure.
1043 */
1044static int unpack_ltab(const struct ubifs_info *c, void *buf)
1045{
1046        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1047        int i, pos = 0, err;
1048
1049        err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LTAB);
1050        if (err)
1051                return err;
1052        for (i = 0; i < c->lpt_lebs; i++) {
1053                int free = ubifs_unpack_bits(c, &addr, &pos, c->lpt_spc_bits);
1054                int dirty = ubifs_unpack_bits(c, &addr, &pos, c->lpt_spc_bits);
1055
1056                if (free < 0 || free > c->leb_size || dirty < 0 ||
1057                    dirty > c->leb_size || free + dirty > c->leb_size)
1058                        return -EINVAL;
1059
1060                c->ltab[i].free = free;
1061                c->ltab[i].dirty = dirty;
1062                c->ltab[i].tgc = 0;
1063                c->ltab[i].cmt = 0;
1064        }
1065        err = check_lpt_crc(c, buf, c->ltab_sz);
1066        return err;
1067}
1068
1069/**
1070 * unpack_lsave - unpack the LPT's save table.
1071 * @c: UBIFS file-system description object
1072 * @buf: buffer from which to unpack
1073 *
1074 * This function returns %0 on success and a negative error code on failure.
1075 */
1076static int unpack_lsave(const struct ubifs_info *c, void *buf)
1077{
1078        uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1079        int i, pos = 0, err;
1080
1081        err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LSAVE);
1082        if (err)
1083                return err;
1084        for (i = 0; i < c->lsave_cnt; i++) {
1085                int lnum = ubifs_unpack_bits(c, &addr, &pos, c->lnum_bits);
1086
1087                if (lnum < c->main_first || lnum >= c->leb_cnt)
1088                        return -EINVAL;
1089                c->lsave[i] = lnum;
1090        }
1091        err = check_lpt_crc(c, buf, c->lsave_sz);
1092        return err;
1093}
1094
1095/**
1096 * validate_nnode - validate a nnode.
1097 * @c: UBIFS file-system description object
1098 * @nnode: nnode to validate
1099 * @parent: parent nnode (or NULL for the root nnode)
1100 * @iip: index in parent
1101 *
1102 * This function returns %0 on success and a negative error code on failure.
1103 */
1104static int validate_nnode(const struct ubifs_info *c, struct ubifs_nnode *nnode,
1105                          struct ubifs_nnode *parent, int iip)
1106{
1107        int i, lvl, max_offs;
1108
1109        if (c->big_lpt) {
1110                int num = calc_nnode_num_from_parent(c, parent, iip);
1111
1112                if (nnode->num != num)
1113                        return -EINVAL;
1114        }
1115        lvl = parent ? parent->level - 1 : c->lpt_hght;
1116        if (lvl < 1)
1117                return -EINVAL;
1118        if (lvl == 1)
1119                max_offs = c->leb_size - c->pnode_sz;
1120        else
1121                max_offs = c->leb_size - c->nnode_sz;
1122        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1123                int lnum = nnode->nbranch[i].lnum;
1124                int offs = nnode->nbranch[i].offs;
1125
1126                if (lnum == 0) {
1127                        if (offs != 0)
1128                                return -EINVAL;
1129                        continue;
1130                }
1131                if (lnum < c->lpt_first || lnum > c->lpt_last)
1132                        return -EINVAL;
1133                if (offs < 0 || offs > max_offs)
1134                        return -EINVAL;
1135        }
1136        return 0;
1137}
1138
1139/**
1140 * validate_pnode - validate a pnode.
1141 * @c: UBIFS file-system description object
1142 * @pnode: pnode to validate
1143 * @parent: parent nnode
1144 * @iip: index in parent
1145 *
1146 * This function returns %0 on success and a negative error code on failure.
1147 */
1148static int validate_pnode(const struct ubifs_info *c, struct ubifs_pnode *pnode,
1149                          struct ubifs_nnode *parent, int iip)
1150{
1151        int i;
1152
1153        if (c->big_lpt) {
1154                int num = calc_pnode_num_from_parent(c, parent, iip);
1155
1156                if (pnode->num != num)
1157                        return -EINVAL;
1158        }
1159        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1160                int free = pnode->lprops[i].free;
1161                int dirty = pnode->lprops[i].dirty;
1162
1163                if (free < 0 || free > c->leb_size || free % c->min_io_size ||
1164                    (free & 7))
1165                        return -EINVAL;
1166                if (dirty < 0 || dirty > c->leb_size || (dirty & 7))
1167                        return -EINVAL;
1168                if (dirty + free > c->leb_size)
1169                        return -EINVAL;
1170        }
1171        return 0;
1172}
1173
1174/**
1175 * set_pnode_lnum - set LEB numbers on a pnode.
1176 * @c: UBIFS file-system description object
1177 * @pnode: pnode to update
1178 *
1179 * This function calculates the LEB numbers for the LEB properties it contains
1180 * based on the pnode number.
1181 */
1182static void set_pnode_lnum(const struct ubifs_info *c,
1183                           struct ubifs_pnode *pnode)
1184{
1185        int i, lnum;
1186
1187        lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + c->main_first;
1188        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1189                if (lnum >= c->leb_cnt)
1190                        return;
1191                pnode->lprops[i].lnum = lnum++;
1192        }
1193}
1194
1195/**
1196 * ubifs_read_nnode - read a nnode from flash and link it to the tree in memory.
1197 * @c: UBIFS file-system description object
1198 * @parent: parent nnode (or NULL for the root)
1199 * @iip: index in parent
1200 *
1201 * This function returns %0 on success and a negative error code on failure.
1202 */
1203int ubifs_read_nnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1204{
1205        struct ubifs_nbranch *branch = NULL;
1206        struct ubifs_nnode *nnode = NULL;
1207        void *buf = c->lpt_nod_buf;
1208        int err, lnum, offs;
1209
1210        if (parent) {
1211                branch = &parent->nbranch[iip];
1212                lnum = branch->lnum;
1213                offs = branch->offs;
1214        } else {
1215                lnum = c->lpt_lnum;
1216                offs = c->lpt_offs;
1217        }
1218        nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_NOFS);
1219        if (!nnode) {
1220                err = -ENOMEM;
1221                goto out;
1222        }
1223        if (lnum == 0) {
1224                /*
1225                 * This nnode was not written which just means that the LEB
1226                 * properties in the subtree below it describe empty LEBs. We
1227                 * make the nnode as though we had read it, which in fact means
1228                 * doing almost nothing.
1229                 */
1230                if (c->big_lpt)
1231                        nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1232        } else {
1233                err = ubifs_leb_read(c, lnum, buf, offs, c->nnode_sz, 1);
1234                if (err)
1235                        goto out;
1236                err = ubifs_unpack_nnode(c, buf, nnode);
1237                if (err)
1238                        goto out;
1239        }
1240        err = validate_nnode(c, nnode, parent, iip);
1241        if (err)
1242                goto out;
1243        if (!c->big_lpt)
1244                nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1245        if (parent) {
1246                branch->nnode = nnode;
1247                nnode->level = parent->level - 1;
1248        } else {
1249                c->nroot = nnode;
1250                nnode->level = c->lpt_hght;
1251        }
1252        nnode->parent = parent;
1253        nnode->iip = iip;
1254        return 0;
1255
1256out:
1257        ubifs_err(c, "error %d reading nnode at %d:%d", err, lnum, offs);
1258        dump_stack();
1259        kfree(nnode);
1260        return err;
1261}
1262
1263/**
1264 * read_pnode - read a pnode from flash and link it to the tree in memory.
1265 * @c: UBIFS file-system description object
1266 * @parent: parent nnode
1267 * @iip: index in parent
1268 *
1269 * This function returns %0 on success and a negative error code on failure.
1270 */
1271static int read_pnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1272{
1273        struct ubifs_nbranch *branch;
1274        struct ubifs_pnode *pnode = NULL;
1275        void *buf = c->lpt_nod_buf;
1276        int err, lnum, offs;
1277
1278        branch = &parent->nbranch[iip];
1279        lnum = branch->lnum;
1280        offs = branch->offs;
1281        pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_NOFS);
1282        if (!pnode)
1283                return -ENOMEM;
1284
1285        if (lnum == 0) {
1286                /*
1287                 * This pnode was not written which just means that the LEB
1288                 * properties in it describe empty LEBs. We make the pnode as
1289                 * though we had read it.
1290                 */
1291                int i;
1292
1293                if (c->big_lpt)
1294                        pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1295                for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1296                        struct ubifs_lprops * const lprops = &pnode->lprops[i];
1297
1298                        lprops->free = c->leb_size;
1299                        lprops->flags = ubifs_categorize_lprops(c, lprops);
1300                }
1301        } else {
1302                err = ubifs_leb_read(c, lnum, buf, offs, c->pnode_sz, 1);
1303                if (err)
1304                        goto out;
1305                err = unpack_pnode(c, buf, pnode);
1306                if (err)
1307                        goto out;
1308        }
1309        err = validate_pnode(c, pnode, parent, iip);
1310        if (err)
1311                goto out;
1312        if (!c->big_lpt)
1313                pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1314        branch->pnode = pnode;
1315        pnode->parent = parent;
1316        pnode->iip = iip;
1317        set_pnode_lnum(c, pnode);
1318        c->pnodes_have += 1;
1319        return 0;
1320
1321out:
1322        ubifs_err(c, "error %d reading pnode at %d:%d", err, lnum, offs);
1323        ubifs_dump_pnode(c, pnode, parent, iip);
1324        dump_stack();
1325        ubifs_err(c, "calc num: %d", calc_pnode_num_from_parent(c, parent, iip));
1326        kfree(pnode);
1327        return err;
1328}
1329
1330/**
1331 * read_ltab - read LPT's own lprops table.
1332 * @c: UBIFS file-system description object
1333 *
1334 * This function returns %0 on success and a negative error code on failure.
1335 */
1336static int read_ltab(struct ubifs_info *c)
1337{
1338        int err;
1339        void *buf;
1340
1341        buf = vmalloc(c->ltab_sz);
1342        if (!buf)
1343                return -ENOMEM;
1344        err = ubifs_leb_read(c, c->ltab_lnum, buf, c->ltab_offs, c->ltab_sz, 1);
1345        if (err)
1346                goto out;
1347        err = unpack_ltab(c, buf);
1348out:
1349        vfree(buf);
1350        return err;
1351}
1352
1353/**
1354 * read_lsave - read LPT's save table.
1355 * @c: UBIFS file-system description object
1356 *
1357 * This function returns %0 on success and a negative error code on failure.
1358 */
1359static int read_lsave(struct ubifs_info *c)
1360{
1361        int err, i;
1362        void *buf;
1363
1364        buf = vmalloc(c->lsave_sz);
1365        if (!buf)
1366                return -ENOMEM;
1367        err = ubifs_leb_read(c, c->lsave_lnum, buf, c->lsave_offs,
1368                             c->lsave_sz, 1);
1369        if (err)
1370                goto out;
1371        err = unpack_lsave(c, buf);
1372        if (err)
1373                goto out;
1374        for (i = 0; i < c->lsave_cnt; i++) {
1375                int lnum = c->lsave[i];
1376                struct ubifs_lprops *lprops;
1377
1378                /*
1379                 * Due to automatic resizing, the values in the lsave table
1380                 * could be beyond the volume size - just ignore them.
1381                 */
1382                if (lnum >= c->leb_cnt)
1383                        continue;
1384                lprops = ubifs_lpt_lookup(c, lnum);
1385                if (IS_ERR(lprops)) {
1386                        err = PTR_ERR(lprops);
1387                        goto out;
1388                }
1389        }
1390out:
1391        vfree(buf);
1392        return err;
1393}
1394
1395/**
1396 * ubifs_get_nnode - get a nnode.
1397 * @c: UBIFS file-system description object
1398 * @parent: parent nnode (or NULL for the root)
1399 * @iip: index in parent
1400 *
1401 * This function returns a pointer to the nnode on success or a negative error
1402 * code on failure.
1403 */
1404struct ubifs_nnode *ubifs_get_nnode(struct ubifs_info *c,
1405                                    struct ubifs_nnode *parent, int iip)
1406{
1407        struct ubifs_nbranch *branch;
1408        struct ubifs_nnode *nnode;
1409        int err;
1410
1411        branch = &parent->nbranch[iip];
1412        nnode = branch->nnode;
1413        if (nnode)
1414                return nnode;
1415        err = ubifs_read_nnode(c, parent, iip);
1416        if (err)
1417                return ERR_PTR(err);
1418        return branch->nnode;
1419}
1420
1421/**
1422 * ubifs_get_pnode - get a pnode.
1423 * @c: UBIFS file-system description object
1424 * @parent: parent nnode
1425 * @iip: index in parent
1426 *
1427 * This function returns a pointer to the pnode on success or a negative error
1428 * code on failure.
1429 */
1430struct ubifs_pnode *ubifs_get_pnode(struct ubifs_info *c,
1431                                    struct ubifs_nnode *parent, int iip)
1432{
1433        struct ubifs_nbranch *branch;
1434        struct ubifs_pnode *pnode;
1435        int err;
1436
1437        branch = &parent->nbranch[iip];
1438        pnode = branch->pnode;
1439        if (pnode)
1440                return pnode;
1441        err = read_pnode(c, parent, iip);
1442        if (err)
1443                return ERR_PTR(err);
1444        update_cats(c, branch->pnode);
1445        return branch->pnode;
1446}
1447
1448/**
1449 * ubifs_pnode_lookup - lookup a pnode in the LPT.
1450 * @c: UBIFS file-system description object
1451 * @i: pnode number (0 to (main_lebs - 1) / UBIFS_LPT_FANOUT)
1452 *
1453 * This function returns a pointer to the pnode on success or a negative
1454 * error code on failure.
1455 */
1456struct ubifs_pnode *ubifs_pnode_lookup(struct ubifs_info *c, int i)
1457{
1458        int err, h, iip, shft;
1459        struct ubifs_nnode *nnode;
1460
1461        if (!c->nroot) {
1462                err = ubifs_read_nnode(c, NULL, 0);
1463                if (err)
1464                        return ERR_PTR(err);
1465        }
1466        i <<= UBIFS_LPT_FANOUT_SHIFT;
1467        nnode = c->nroot;
1468        shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1469        for (h = 1; h < c->lpt_hght; h++) {
1470                iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1471                shft -= UBIFS_LPT_FANOUT_SHIFT;
1472                nnode = ubifs_get_nnode(c, nnode, iip);
1473                if (IS_ERR(nnode))
1474                        return ERR_CAST(nnode);
1475        }
1476        iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1477        return ubifs_get_pnode(c, nnode, iip);
1478}
1479
1480/**
1481 * ubifs_lpt_lookup - lookup LEB properties in the LPT.
1482 * @c: UBIFS file-system description object
1483 * @lnum: LEB number to lookup
1484 *
1485 * This function returns a pointer to the LEB properties on success or a
1486 * negative error code on failure.
1487 */
1488struct ubifs_lprops *ubifs_lpt_lookup(struct ubifs_info *c, int lnum)
1489{
1490        int i, iip;
1491        struct ubifs_pnode *pnode;
1492
1493        i = lnum - c->main_first;
1494        pnode = ubifs_pnode_lookup(c, i >> UBIFS_LPT_FANOUT_SHIFT);
1495        if (IS_ERR(pnode))
1496                return ERR_CAST(pnode);
1497        iip = (i & (UBIFS_LPT_FANOUT - 1));
1498        dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
1499               pnode->lprops[iip].free, pnode->lprops[iip].dirty,
1500               pnode->lprops[iip].flags);
1501        return &pnode->lprops[iip];
1502}
1503
1504/**
1505 * dirty_cow_nnode - ensure a nnode is not being committed.
1506 * @c: UBIFS file-system description object
1507 * @nnode: nnode to check
1508 *
1509 * Returns dirtied nnode on success or negative error code on failure.
1510 */
1511static struct ubifs_nnode *dirty_cow_nnode(struct ubifs_info *c,
1512                                           struct ubifs_nnode *nnode)
1513{
1514        struct ubifs_nnode *n;
1515        int i;
1516
1517        if (!test_bit(COW_CNODE, &nnode->flags)) {
1518                /* nnode is not being committed */
1519                if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
1520                        c->dirty_nn_cnt += 1;
1521                        ubifs_add_nnode_dirt(c, nnode);
1522                }
1523                return nnode;
1524        }
1525
1526        /* nnode is being committed, so copy it */
1527        n = kmemdup(nnode, sizeof(struct ubifs_nnode), GFP_NOFS);
1528        if (unlikely(!n))
1529                return ERR_PTR(-ENOMEM);
1530
1531        n->cnext = NULL;
1532        __set_bit(DIRTY_CNODE, &n->flags);
1533        __clear_bit(COW_CNODE, &n->flags);
1534
1535        /* The children now have new parent */
1536        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1537                struct ubifs_nbranch *branch = &n->nbranch[i];
1538
1539                if (branch->cnode)
1540                        branch->cnode->parent = n;
1541        }
1542
1543        ubifs_assert(c, !test_bit(OBSOLETE_CNODE, &nnode->flags));
1544        __set_bit(OBSOLETE_CNODE, &nnode->flags);
1545
1546        c->dirty_nn_cnt += 1;
1547        ubifs_add_nnode_dirt(c, nnode);
1548        if (nnode->parent)
1549                nnode->parent->nbranch[n->iip].nnode = n;
1550        else
1551                c->nroot = n;
1552        return n;
1553}
1554
1555/**
1556 * dirty_cow_pnode - ensure a pnode is not being committed.
1557 * @c: UBIFS file-system description object
1558 * @pnode: pnode to check
1559 *
1560 * Returns dirtied pnode on success or negative error code on failure.
1561 */
1562static struct ubifs_pnode *dirty_cow_pnode(struct ubifs_info *c,
1563                                           struct ubifs_pnode *pnode)
1564{
1565        struct ubifs_pnode *p;
1566
1567        if (!test_bit(COW_CNODE, &pnode->flags)) {
1568                /* pnode is not being committed */
1569                if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
1570                        c->dirty_pn_cnt += 1;
1571                        add_pnode_dirt(c, pnode);
1572                }
1573                return pnode;
1574        }
1575
1576        /* pnode is being committed, so copy it */
1577        p = kmemdup(pnode, sizeof(struct ubifs_pnode), GFP_NOFS);
1578        if (unlikely(!p))
1579                return ERR_PTR(-ENOMEM);
1580
1581        p->cnext = NULL;
1582        __set_bit(DIRTY_CNODE, &p->flags);
1583        __clear_bit(COW_CNODE, &p->flags);
1584        replace_cats(c, pnode, p);
1585
1586        ubifs_assert(c, !test_bit(OBSOLETE_CNODE, &pnode->flags));
1587        __set_bit(OBSOLETE_CNODE, &pnode->flags);
1588
1589        c->dirty_pn_cnt += 1;
1590        add_pnode_dirt(c, pnode);
1591        pnode->parent->nbranch[p->iip].pnode = p;
1592        return p;
1593}
1594
1595/**
1596 * ubifs_lpt_lookup_dirty - lookup LEB properties in the LPT.
1597 * @c: UBIFS file-system description object
1598 * @lnum: LEB number to lookup
1599 *
1600 * This function returns a pointer to the LEB properties on success or a
1601 * negative error code on failure.
1602 */
1603struct ubifs_lprops *ubifs_lpt_lookup_dirty(struct ubifs_info *c, int lnum)
1604{
1605        int err, i, h, iip, shft;
1606        struct ubifs_nnode *nnode;
1607        struct ubifs_pnode *pnode;
1608
1609        if (!c->nroot) {
1610                err = ubifs_read_nnode(c, NULL, 0);
1611                if (err)
1612                        return ERR_PTR(err);
1613        }
1614        nnode = c->nroot;
1615        nnode = dirty_cow_nnode(c, nnode);
1616        if (IS_ERR(nnode))
1617                return ERR_CAST(nnode);
1618        i = lnum - c->main_first;
1619        shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1620        for (h = 1; h < c->lpt_hght; h++) {
1621                iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1622                shft -= UBIFS_LPT_FANOUT_SHIFT;
1623                nnode = ubifs_get_nnode(c, nnode, iip);
1624                if (IS_ERR(nnode))
1625                        return ERR_CAST(nnode);
1626                nnode = dirty_cow_nnode(c, nnode);
1627                if (IS_ERR(nnode))
1628                        return ERR_CAST(nnode);
1629        }
1630        iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1631        pnode = ubifs_get_pnode(c, nnode, iip);
1632        if (IS_ERR(pnode))
1633                return ERR_CAST(pnode);
1634        pnode = dirty_cow_pnode(c, pnode);
1635        if (IS_ERR(pnode))
1636                return ERR_CAST(pnode);
1637        iip = (i & (UBIFS_LPT_FANOUT - 1));
1638        dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
1639               pnode->lprops[iip].free, pnode->lprops[iip].dirty,
1640               pnode->lprops[iip].flags);
1641        ubifs_assert(c, test_bit(DIRTY_CNODE, &pnode->flags));
1642        return &pnode->lprops[iip];
1643}
1644
1645/**
1646 * ubifs_lpt_calc_hash - Calculate hash of the LPT pnodes
1647 * @c: UBIFS file-system description object
1648 * @hash: the returned hash of the LPT pnodes
1649 *
1650 * This function iterates over the LPT pnodes and creates a hash over them.
1651 * Returns 0 for success or a negative error code otherwise.
1652 */
1653int ubifs_lpt_calc_hash(struct ubifs_info *c, u8 *hash)
1654{
1655        struct ubifs_nnode *nnode, *nn;
1656        struct ubifs_cnode *cnode;
1657        struct shash_desc *desc;
1658        int iip = 0, i;
1659        int bufsiz = max_t(int, c->nnode_sz, c->pnode_sz);
1660        void *buf;
1661        int err;
1662
1663        if (!ubifs_authenticated(c))
1664                return 0;
1665
1666        if (!c->nroot) {
1667                err = ubifs_read_nnode(c, NULL, 0);
1668                if (err)
1669                        return err;
1670        }
1671
1672        desc = ubifs_hash_get_desc(c);
1673        if (IS_ERR(desc))
1674                return PTR_ERR(desc);
1675
1676        buf = kmalloc(bufsiz, GFP_NOFS);
1677        if (!buf) {
1678                err = -ENOMEM;
1679                goto out;
1680        }
1681
1682        cnode = (struct ubifs_cnode *)c->nroot;
1683
1684        while (cnode) {
1685                nnode = cnode->parent;
1686                nn = (struct ubifs_nnode *)cnode;
1687                if (cnode->level > 1) {
1688                        while (iip < UBIFS_LPT_FANOUT) {
1689                                if (nn->nbranch[iip].lnum == 0) {
1690                                        /* Go right */
1691                                        iip++;
1692                                        continue;
1693                                }
1694
1695                                nnode = ubifs_get_nnode(c, nn, iip);
1696                                if (IS_ERR(nnode)) {
1697                                        err = PTR_ERR(nnode);
1698                                        goto out;
1699                                }
1700
1701                                /* Go down */
1702                                iip = 0;
1703                                cnode = (struct ubifs_cnode *)nnode;
1704                                break;
1705                        }
1706                        if (iip < UBIFS_LPT_FANOUT)
1707                                continue;
1708                } else {
1709                        struct ubifs_pnode *pnode;
1710
1711                        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1712                                if (nn->nbranch[i].lnum == 0)
1713                                        continue;
1714                                pnode = ubifs_get_pnode(c, nn, i);
1715                                if (IS_ERR(pnode)) {
1716                                        err = PTR_ERR(pnode);
1717                                        goto out;
1718                                }
1719
1720                                ubifs_pack_pnode(c, buf, pnode);
1721                                err = ubifs_shash_update(c, desc, buf,
1722                                                         c->pnode_sz);
1723                                if (err)
1724                                        goto out;
1725                        }
1726                }
1727                /* Go up and to the right */
1728                iip = cnode->iip + 1;
1729                cnode = (struct ubifs_cnode *)nnode;
1730        }
1731
1732        err = ubifs_shash_final(c, desc, hash);
1733out:
1734        kfree(desc);
1735        kfree(buf);
1736
1737        return err;
1738}
1739
1740/**
1741 * lpt_check_hash - check the hash of the LPT.
1742 * @c: UBIFS file-system description object
1743 *
1744 * This function calculates a hash over all pnodes in the LPT and compares it with
1745 * the hash stored in the master node. Returns %0 on success and a negative error
1746 * code on failure.
1747 */
1748static int lpt_check_hash(struct ubifs_info *c)
1749{
1750        int err;
1751        u8 hash[UBIFS_HASH_ARR_SZ];
1752
1753        if (!ubifs_authenticated(c))
1754                return 0;
1755
1756        err = ubifs_lpt_calc_hash(c, hash);
1757        if (err)
1758                return err;
1759
1760        if (ubifs_check_hash(c, c->mst_node->hash_lpt, hash)) {
1761                err = -EPERM;
1762                ubifs_err(c, "Failed to authenticate LPT");
1763        } else {
1764                err = 0;
1765        }
1766
1767        return err;
1768}
1769
1770/**
1771 * lpt_init_rd - initialize the LPT for reading.
1772 * @c: UBIFS file-system description object
1773 *
1774 * This function returns %0 on success and a negative error code on failure.
1775 */
1776static int lpt_init_rd(struct ubifs_info *c)
1777{
1778        int err, i;
1779
1780        c->ltab = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
1781                                     c->lpt_lebs));
1782        if (!c->ltab)
1783                return -ENOMEM;
1784
1785        i = max_t(int, c->nnode_sz, c->pnode_sz);
1786        c->lpt_nod_buf = kmalloc(i, GFP_KERNEL);
1787        if (!c->lpt_nod_buf)
1788                return -ENOMEM;
1789
1790        for (i = 0; i < LPROPS_HEAP_CNT; i++) {
1791                c->lpt_heap[i].arr = kmalloc_array(LPT_HEAP_SZ,
1792                                                   sizeof(void *),
1793                                                   GFP_KERNEL);
1794                if (!c->lpt_heap[i].arr)
1795                        return -ENOMEM;
1796                c->lpt_heap[i].cnt = 0;
1797                c->lpt_heap[i].max_cnt = LPT_HEAP_SZ;
1798        }
1799
1800        c->dirty_idx.arr = kmalloc_array(LPT_HEAP_SZ, sizeof(void *),
1801                                         GFP_KERNEL);
1802        if (!c->dirty_idx.arr)
1803                return -ENOMEM;
1804        c->dirty_idx.cnt = 0;
1805        c->dirty_idx.max_cnt = LPT_HEAP_SZ;
1806
1807        err = read_ltab(c);
1808        if (err)
1809                return err;
1810
1811        err = lpt_check_hash(c);
1812        if (err)
1813                return err;
1814
1815        dbg_lp("space_bits %d", c->space_bits);
1816        dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
1817        dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
1818        dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
1819        dbg_lp("pcnt_bits %d", c->pcnt_bits);
1820        dbg_lp("lnum_bits %d", c->lnum_bits);
1821        dbg_lp("pnode_sz %d", c->pnode_sz);
1822        dbg_lp("nnode_sz %d", c->nnode_sz);
1823        dbg_lp("ltab_sz %d", c->ltab_sz);
1824        dbg_lp("lsave_sz %d", c->lsave_sz);
1825        dbg_lp("lsave_cnt %d", c->lsave_cnt);
1826        dbg_lp("lpt_hght %d", c->lpt_hght);
1827        dbg_lp("big_lpt %d", c->big_lpt);
1828        dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
1829        dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
1830        dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
1831        if (c->big_lpt)
1832                dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
1833
1834        return 0;
1835}
1836
1837/**
1838 * lpt_init_wr - initialize the LPT for writing.
1839 * @c: UBIFS file-system description object
1840 *
1841 * 'lpt_init_rd()' must have been called already.
1842 *
1843 * This function returns %0 on success and a negative error code on failure.
1844 */
1845static int lpt_init_wr(struct ubifs_info *c)
1846{
1847        int err, i;
1848
1849        c->ltab_cmt = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
1850                                         c->lpt_lebs));
1851        if (!c->ltab_cmt)
1852                return -ENOMEM;
1853
1854        c->lpt_buf = vmalloc(c->leb_size);
1855        if (!c->lpt_buf)
1856                return -ENOMEM;
1857
1858        if (c->big_lpt) {
1859                c->lsave = kmalloc_array(c->lsave_cnt, sizeof(int), GFP_NOFS);
1860                if (!c->lsave)
1861                        return -ENOMEM;
1862                err = read_lsave(c);
1863                if (err)
1864                        return err;
1865        }
1866
1867        for (i = 0; i < c->lpt_lebs; i++)
1868                if (c->ltab[i].free == c->leb_size) {
1869                        err = ubifs_leb_unmap(c, i + c->lpt_first);
1870                        if (err)
1871                                return err;
1872                }
1873
1874        return 0;
1875}
1876
1877/**
1878 * ubifs_lpt_init - initialize the LPT.
1879 * @c: UBIFS file-system description object
1880 * @rd: whether to initialize lpt for reading
1881 * @wr: whether to initialize lpt for writing
1882 *
1883 * For mounting 'rw', @rd and @wr are both true. For mounting 'ro', @rd is true
1884 * and @wr is false. For mounting from 'ro' to 'rw', @rd is false and @wr is
1885 * true.
1886 *
1887 * This function returns %0 on success and a negative error code on failure.
1888 */
1889int ubifs_lpt_init(struct ubifs_info *c, int rd, int wr)
1890{
1891        int err;
1892
1893        if (rd) {
1894                err = lpt_init_rd(c);
1895                if (err)
1896                        goto out_err;
1897        }
1898
1899        if (wr) {
1900                err = lpt_init_wr(c);
1901                if (err)
1902                        goto out_err;
1903        }
1904
1905        return 0;
1906
1907out_err:
1908        if (wr)
1909                ubifs_lpt_free(c, 1);
1910        if (rd)
1911                ubifs_lpt_free(c, 0);
1912        return err;
1913}
1914
1915/**
1916 * struct lpt_scan_node - somewhere to put nodes while we scan LPT.
1917 * @nnode: where to keep a nnode
1918 * @pnode: where to keep a pnode
1919 * @cnode: where to keep a cnode
1920 * @in_tree: is the node in the tree in memory
1921 * @ptr.nnode: pointer to the nnode (if it is an nnode) which may be here or in
1922 * the tree
1923 * @ptr.pnode: ditto for pnode
1924 * @ptr.cnode: ditto for cnode
1925 */
1926struct lpt_scan_node {
1927        union {
1928                struct ubifs_nnode nnode;
1929                struct ubifs_pnode pnode;
1930                struct ubifs_cnode cnode;
1931        };
1932        int in_tree;
1933        union {
1934                struct ubifs_nnode *nnode;
1935                struct ubifs_pnode *pnode;
1936                struct ubifs_cnode *cnode;
1937        } ptr;
1938};
1939
1940/**
1941 * scan_get_nnode - for the scan, get a nnode from either the tree or flash.
1942 * @c: the UBIFS file-system description object
1943 * @path: where to put the nnode
1944 * @parent: parent of the nnode
1945 * @iip: index in parent of the nnode
1946 *
1947 * This function returns a pointer to the nnode on success or a negative error
1948 * code on failure.
1949 */
1950static struct ubifs_nnode *scan_get_nnode(struct ubifs_info *c,
1951                                          struct lpt_scan_node *path,
1952                                          struct ubifs_nnode *parent, int iip)
1953{
1954        struct ubifs_nbranch *branch;
1955        struct ubifs_nnode *nnode;
1956        void *buf = c->lpt_nod_buf;
1957        int err;
1958
1959        branch = &parent->nbranch[iip];
1960        nnode = branch->nnode;
1961        if (nnode) {
1962                path->in_tree = 1;
1963                path->ptr.nnode = nnode;
1964                return nnode;
1965        }
1966        nnode = &path->nnode;
1967        path->in_tree = 0;
1968        path->ptr.nnode = nnode;
1969        memset(nnode, 0, sizeof(struct ubifs_nnode));
1970        if (branch->lnum == 0) {
1971                /*
1972                 * This nnode was not written which just means that the LEB
1973                 * properties in the subtree below it describe empty LEBs. We
1974                 * make the nnode as though we had read it, which in fact means
1975                 * doing almost nothing.
1976                 */
1977                if (c->big_lpt)
1978                        nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1979        } else {
1980                err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
1981                                     c->nnode_sz, 1);
1982                if (err)
1983                        return ERR_PTR(err);
1984                err = ubifs_unpack_nnode(c, buf, nnode);
1985                if (err)
1986                        return ERR_PTR(err);
1987        }
1988        err = validate_nnode(c, nnode, parent, iip);
1989        if (err)
1990                return ERR_PTR(err);
1991        if (!c->big_lpt)
1992                nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1993        nnode->level = parent->level - 1;
1994        nnode->parent = parent;
1995        nnode->iip = iip;
1996        return nnode;
1997}
1998
1999/**
2000 * scan_get_pnode - for the scan, get a pnode from either the tree or flash.
2001 * @c: the UBIFS file-system description object
2002 * @path: where to put the pnode
2003 * @parent: parent of the pnode
2004 * @iip: index in parent of the pnode
2005 *
2006 * This function returns a pointer to the pnode on success or a negative error
2007 * code on failure.
2008 */
2009static struct ubifs_pnode *scan_get_pnode(struct ubifs_info *c,
2010                                          struct lpt_scan_node *path,
2011                                          struct ubifs_nnode *parent, int iip)
2012{
2013        struct ubifs_nbranch *branch;
2014        struct ubifs_pnode *pnode;
2015        void *buf = c->lpt_nod_buf;
2016        int err;
2017
2018        branch = &parent->nbranch[iip];
2019        pnode = branch->pnode;
2020        if (pnode) {
2021                path->in_tree = 1;
2022                path->ptr.pnode = pnode;
2023                return pnode;
2024        }
2025        pnode = &path->pnode;
2026        path->in_tree = 0;
2027        path->ptr.pnode = pnode;
2028        memset(pnode, 0, sizeof(struct ubifs_pnode));
2029        if (branch->lnum == 0) {
2030                /*
2031                 * This pnode was not written which just means that the LEB
2032                 * properties in it describe empty LEBs. We make the pnode as
2033                 * though we had read it.
2034                 */
2035                int i;
2036
2037                if (c->big_lpt)
2038                        pnode->num = calc_pnode_num_from_parent(c, parent, iip);
2039                for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
2040                        struct ubifs_lprops * const lprops = &pnode->lprops[i];
2041
2042                        lprops->free = c->leb_size;
2043                        lprops->flags = ubifs_categorize_lprops(c, lprops);
2044                }
2045        } else {
2046                ubifs_assert(c, branch->lnum >= c->lpt_first &&
2047                             branch->lnum <= c->lpt_last);
2048                ubifs_assert(c, branch->offs >= 0 && branch->offs < c->leb_size);
2049                err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
2050                                     c->pnode_sz, 1);
2051                if (err)
2052                        return ERR_PTR(err);
2053                err = unpack_pnode(c, buf, pnode);
2054                if (err)
2055                        return ERR_PTR(err);
2056        }
2057        err = validate_pnode(c, pnode, parent, iip);
2058        if (err)
2059                return ERR_PTR(err);
2060        if (!c->big_lpt)
2061                pnode->num = calc_pnode_num_from_parent(c, parent, iip);
2062        pnode->parent = parent;
2063        pnode->iip = iip;
2064        set_pnode_lnum(c, pnode);
2065        return pnode;
2066}
2067
2068/**
2069 * ubifs_lpt_scan_nolock - scan the LPT.
2070 * @c: the UBIFS file-system description object
2071 * @start_lnum: LEB number from which to start scanning
2072 * @end_lnum: LEB number at which to stop scanning
2073 * @scan_cb: callback function called for each lprops
2074 * @data: data to be passed to the callback function
2075 *
2076 * This function returns %0 on success and a negative error code on failure.
2077 */
2078int ubifs_lpt_scan_nolock(struct ubifs_info *c, int start_lnum, int end_lnum,
2079                          ubifs_lpt_scan_callback scan_cb, void *data)
2080{
2081        int err = 0, i, h, iip, shft;
2082        struct ubifs_nnode *nnode;
2083        struct ubifs_pnode *pnode;
2084        struct lpt_scan_node *path;
2085
2086        if (start_lnum == -1) {
2087                start_lnum = end_lnum + 1;
2088                if (start_lnum >= c->leb_cnt)
2089                        start_lnum = c->main_first;
2090        }
2091
2092        ubifs_assert(c, start_lnum >= c->main_first && start_lnum < c->leb_cnt);
2093        ubifs_assert(c, end_lnum >= c->main_first && end_lnum < c->leb_cnt);
2094
2095        if (!c->nroot) {
2096                err = ubifs_read_nnode(c, NULL, 0);
2097                if (err)
2098                        return err;
2099        }
2100
2101        path = kmalloc_array(c->lpt_hght + 1, sizeof(struct lpt_scan_node),
2102                             GFP_NOFS);
2103        if (!path)
2104                return -ENOMEM;
2105
2106        path[0].ptr.nnode = c->nroot;
2107        path[0].in_tree = 1;
2108again:
2109        /* Descend to the pnode containing start_lnum */
2110        nnode = c->nroot;
2111        i = start_lnum - c->main_first;
2112        shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
2113        for (h = 1; h < c->lpt_hght; h++) {
2114                iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
2115                shft -= UBIFS_LPT_FANOUT_SHIFT;
2116                nnode = scan_get_nnode(c, path + h, nnode, iip);
2117                if (IS_ERR(nnode)) {
2118                        err = PTR_ERR(nnode);
2119                        goto out;
2120                }
2121        }
2122        iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
2123        pnode = scan_get_pnode(c, path + h, nnode, iip);
2124        if (IS_ERR(pnode)) {
2125                err = PTR_ERR(pnode);
2126                goto out;
2127        }
2128        iip = (i & (UBIFS_LPT_FANOUT - 1));
2129
2130        /* Loop for each lprops */
2131        while (1) {
2132                struct ubifs_lprops *lprops = &pnode->lprops[iip];
2133                int ret, lnum = lprops->lnum;
2134
2135                ret = scan_cb(c, lprops, path[h].in_tree, data);
2136                if (ret < 0) {
2137                        err = ret;
2138                        goto out;
2139                }
2140                if (ret & LPT_SCAN_ADD) {
2141                        /* Add all the nodes in path to the tree in memory */
2142                        for (h = 1; h < c->lpt_hght; h++) {
2143                                const size_t sz = sizeof(struct ubifs_nnode);
2144                                struct ubifs_nnode *parent;
2145
2146                                if (path[h].in_tree)
2147                                        continue;
2148                                nnode = kmemdup(&path[h].nnode, sz, GFP_NOFS);
2149                                if (!nnode) {
2150                                        err = -ENOMEM;
2151                                        goto out;
2152                                }
2153                                parent = nnode->parent;
2154                                parent->nbranch[nnode->iip].nnode = nnode;
2155                                path[h].ptr.nnode = nnode;
2156                                path[h].in_tree = 1;
2157                                path[h + 1].cnode.parent = nnode;
2158                        }
2159                        if (path[h].in_tree)
2160                                ubifs_ensure_cat(c, lprops);
2161                        else {
2162                                const size_t sz = sizeof(struct ubifs_pnode);
2163                                struct ubifs_nnode *parent;
2164
2165                                pnode = kmemdup(&path[h].pnode, sz, GFP_NOFS);
2166                                if (!pnode) {
2167                                        err = -ENOMEM;
2168                                        goto out;
2169                                }
2170                                parent = pnode->parent;
2171                                parent->nbranch[pnode->iip].pnode = pnode;
2172                                path[h].ptr.pnode = pnode;
2173                                path[h].in_tree = 1;
2174                                update_cats(c, pnode);
2175                                c->pnodes_have += 1;
2176                        }
2177                        err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)
2178                                                  c->nroot, 0, 0);
2179                        if (err)
2180                                goto out;
2181                        err = dbg_check_cats(c);
2182                        if (err)
2183                                goto out;
2184                }
2185                if (ret & LPT_SCAN_STOP) {
2186                        err = 0;
2187                        break;
2188                }
2189                /* Get the next lprops */
2190                if (lnum == end_lnum) {
2191                        /*
2192                         * We got to the end without finding what we were
2193                         * looking for
2194                         */
2195                        err = -ENOSPC;
2196                        goto out;
2197                }
2198                if (lnum + 1 >= c->leb_cnt) {
2199                        /* Wrap-around to the beginning */
2200                        start_lnum = c->main_first;
2201                        goto again;
2202                }
2203                if (iip + 1 < UBIFS_LPT_FANOUT) {
2204                        /* Next lprops is in the same pnode */
2205                        iip += 1;
2206                        continue;
2207                }
2208                /* We need to get the next pnode. Go up until we can go right */
2209                iip = pnode->iip;
2210                while (1) {
2211                        h -= 1;
2212                        ubifs_assert(c, h >= 0);
2213                        nnode = path[h].ptr.nnode;
2214                        if (iip + 1 < UBIFS_LPT_FANOUT)
2215                                break;
2216                        iip = nnode->iip;
2217                }
2218                /* Go right */
2219                iip += 1;
2220                /* Descend to the pnode */
2221                h += 1;
2222                for (; h < c->lpt_hght; h++) {
2223                        nnode = scan_get_nnode(c, path + h, nnode, iip);
2224                        if (IS_ERR(nnode)) {
2225                                err = PTR_ERR(nnode);
2226                                goto out;
2227                        }
2228                        iip = 0;
2229                }
2230                pnode = scan_get_pnode(c, path + h, nnode, iip);
2231                if (IS_ERR(pnode)) {
2232                        err = PTR_ERR(pnode);
2233                        goto out;
2234                }
2235                iip = 0;
2236        }
2237out:
2238        kfree(path);
2239        return err;
2240}
2241
2242/**
2243 * dbg_chk_pnode - check a pnode.
2244 * @c: the UBIFS file-system description object
2245 * @pnode: pnode to check
2246 * @col: pnode column
2247 *
2248 * This function returns %0 on success and a negative error code on failure.
2249 */
2250static int dbg_chk_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
2251                         int col)
2252{
2253        int i;
2254
2255        if (pnode->num != col) {
2256                ubifs_err(c, "pnode num %d expected %d parent num %d iip %d",
2257                          pnode->num, col, pnode->parent->num, pnode->iip);
2258                return -EINVAL;
2259        }
2260        for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
2261                struct ubifs_lprops *lp, *lprops = &pnode->lprops[i];
2262                int lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + i +
2263                           c->main_first;
2264                int found, cat = lprops->flags & LPROPS_CAT_MASK;
2265                struct ubifs_lpt_heap *heap;
2266                struct list_head *list = NULL;
2267
2268                if (lnum >= c->leb_cnt)
2269                        continue;
2270                if (lprops->lnum != lnum) {
2271                        ubifs_err(c, "bad LEB number %d expected %d",
2272                                  lprops->lnum, lnum);
2273                        return -EINVAL;
2274                }
2275                if (lprops->flags & LPROPS_TAKEN) {
2276                        if (cat != LPROPS_UNCAT) {
2277                                ubifs_err(c, "LEB %d taken but not uncat %d",
2278                                          lprops->lnum, cat);
2279                                return -EINVAL;
2280                        }
2281                        continue;
2282                }
2283                if (lprops->flags & LPROPS_INDEX) {
2284                        switch (cat) {
2285                        case LPROPS_UNCAT:
2286                        case LPROPS_DIRTY_IDX:
2287                        case LPROPS_FRDI_IDX:
2288                                break;
2289                        default:
2290                                ubifs_err(c, "LEB %d index but cat %d",
2291                                          lprops->lnum, cat);
2292                                return -EINVAL;
2293                        }
2294                } else {
2295                        switch (cat) {
2296                        case LPROPS_UNCAT:
2297                        case LPROPS_DIRTY:
2298                        case LPROPS_FREE:
2299                        case LPROPS_EMPTY:
2300                        case LPROPS_FREEABLE:
2301                                break;
2302                        default:
2303                                ubifs_err(c, "LEB %d not index but cat %d",
2304                                          lprops->lnum, cat);
2305                                return -EINVAL;
2306                        }
2307                }
2308                switch (cat) {
2309                case LPROPS_UNCAT:
2310                        list = &c->uncat_list;
2311                        break;
2312                case LPROPS_EMPTY:
2313                        list = &c->empty_list;
2314                        break;
2315                case LPROPS_FREEABLE:
2316                        list = &c->freeable_list;
2317                        break;
2318                case LPROPS_FRDI_IDX:
2319                        list = &c->frdi_idx_list;
2320                        break;
2321                }
2322                found = 0;
2323                switch (cat) {
2324                case LPROPS_DIRTY:
2325                case LPROPS_DIRTY_IDX:
2326                case LPROPS_FREE:
2327                        heap = &c->lpt_heap[cat - 1];
2328                        if (lprops->hpos < heap->cnt &&
2329                            heap->arr[lprops->hpos] == lprops)
2330                                found = 1;
2331                        break;
2332                case LPROPS_UNCAT:
2333                case LPROPS_EMPTY:
2334                case LPROPS_FREEABLE:
2335                case LPROPS_FRDI_IDX:
2336                        list_for_each_entry(lp, list, list)
2337                                if (lprops == lp) {
2338                                        found = 1;
2339                                        break;
2340                                }
2341                        break;
2342                }
2343                if (!found) {
2344                        ubifs_err(c, "LEB %d cat %d not found in cat heap/list",
2345                                  lprops->lnum, cat);
2346                        return -EINVAL;
2347                }
2348                switch (cat) {
2349                case LPROPS_EMPTY:
2350                        if (lprops->free != c->leb_size) {
2351                                ubifs_err(c, "LEB %d cat %d free %d dirty %d",
2352                                          lprops->lnum, cat, lprops->free,
2353                                          lprops->dirty);
2354                                return -EINVAL;
2355                        }
2356                        break;
2357                case LPROPS_FREEABLE:
2358                case LPROPS_FRDI_IDX:
2359                        if (lprops->free + lprops->dirty != c->leb_size) {
2360                                ubifs_err(c, "LEB %d cat %d free %d dirty %d",
2361                                          lprops->lnum, cat, lprops->free,
2362                                          lprops->dirty);
2363                                return -EINVAL;
2364                        }
2365                        break;
2366                }
2367        }
2368        return 0;
2369}
2370
2371/**
2372 * dbg_check_lpt_nodes - check nnodes and pnodes.
2373 * @c: the UBIFS file-system description object
2374 * @cnode: next cnode (nnode or pnode) to check
2375 * @row: row of cnode (root is zero)
2376 * @col: column of cnode (leftmost is zero)
2377 *
2378 * This function returns %0 on success and a negative error code on failure.
2379 */
2380int dbg_check_lpt_nodes(struct ubifs_info *c, struct ubifs_cnode *cnode,
2381                        int row, int col)
2382{
2383        struct ubifs_nnode *nnode, *nn;
2384        struct ubifs_cnode *cn;
2385        int num, iip = 0, err;
2386
2387        if (!dbg_is_chk_lprops(c))
2388                return 0;
2389
2390        while (cnode) {
2391                ubifs_assert(c, row >= 0);
2392                nnode = cnode->parent;
2393                if (cnode->level) {
2394                        /* cnode is a nnode */
2395                        num = calc_nnode_num(row, col);
2396                        if (cnode->num != num) {
2397                                ubifs_err(c, "nnode num %d expected %d parent num %d iip %d",
2398                                          cnode->num, num,
2399                                          (nnode ? nnode->num : 0), cnode->iip);
2400                                return -EINVAL;
2401                        }
2402                        nn = (struct ubifs_nnode *)cnode;
2403                        while (iip < UBIFS_LPT_FANOUT) {
2404                                cn = nn->nbranch[iip].cnode;
2405                                if (cn) {
2406                                        /* Go down */
2407                                        row += 1;
2408                                        col <<= UBIFS_LPT_FANOUT_SHIFT;
2409                                        col += iip;
2410                                        iip = 0;
2411                                        cnode = cn;
2412                                        break;
2413                                }
2414                                /* Go right */
2415                                iip += 1;
2416                        }
2417                        if (iip < UBIFS_LPT_FANOUT)
2418                                continue;
2419                } else {
2420                        struct ubifs_pnode *pnode;
2421
2422                        /* cnode is a pnode */
2423                        pnode = (struct ubifs_pnode *)cnode;
2424                        err = dbg_chk_pnode(c, pnode, col);
2425                        if (err)
2426                                return err;
2427                }
2428                /* Go up and to the right */
2429                row -= 1;
2430                col >>= UBIFS_LPT_FANOUT_SHIFT;
2431                iip = cnode->iip + 1;
2432                cnode = (struct ubifs_cnode *)nnode;
2433        }
2434        return 0;
2435}
2436