fs/ubifs/lpt.c

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This source file includes following definitions.
do_calc_lpt_geom
ubifs_calc_lpt_geom
calc_dflt_lpt_geom
pack_bits
ubifs_unpack_bits
ubifs_pack_pnode
ubifs_pack_nnode
ubifs_pack_ltab
ubifs_pack_lsave
ubifs_add_lpt_dirt
set_ltab
ubifs_add_nnode_dirt
add_pnode_dirt
calc_nnode_num
calc_nnode_num_from_parent
calc_pnode_num_from_parent
ubifs_create_dflt_lpt
update_cats
replace_cats
check_lpt_crc
check_lpt_type
unpack_pnode
ubifs_unpack_nnode
unpack_ltab
unpack_lsave
validate_nnode
validate_pnode
set_pnode_lnum
ubifs_read_nnode
read_pnode
read_ltab
read_lsave
ubifs_get_nnode
ubifs_get_pnode
ubifs_pnode_lookup
ubifs_lpt_lookup
dirty_cow_nnode
dirty_cow_pnode
ubifs_lpt_lookup_dirty
ubifs_lpt_calc_hash
lpt_check_hash
lpt_init_rd
lpt_init_wr
ubifs_lpt_init
scan_get_nnode
scan_get_pnode
ubifs_lpt_scan_nolock
dbg_chk_pnode
dbg_check_lpt_nodes
   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  */
  46 static 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  */
 125 int 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  */
 162 static 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  */
 222 static 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  */
 273 uint32_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  */
 340 void 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  */
 373 void 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  */
 405 void 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  */
 430 void 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  */
 452 void 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  */
 469 static 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  */
 484 void 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  */
 505 static 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  */
 522 static 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  */
 548 static 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  */
 573 static 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  */
 599 int 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);
 860 out:
 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  */
 879 static 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  */
 903 static 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  */
 924 static 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  */
 951 static 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  */
 974 static 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  */
1011 int 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  */
1044 static 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  */
1076 static 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  */
1104 static 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  */
1148 static 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  */
1182 static 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  */
1203 int 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 
1256 out:
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  */
1271 static 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 
1321 out:
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  */
1336 static 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);
1348 out:
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  */
1359 static 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         }
1390 out:
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  */
1404 struct 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  */
1430 struct 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  */
1456 struct 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  */
1488 struct 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  */
1511 static 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  */
1562 static 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  */
1603 struct 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  */
1653 int 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);
1733 out:
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  */
1748 static 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  */
1776 static 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  */
1845 static 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  */
1889 int 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 
1907 out_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  */
1926 struct 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  */
1950 static 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  */
2009 static 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  */
2078 int 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;
2108 again:
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         }
2237 out:
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  */
2250 static 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  */
2380 int 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 }
/* [<][>][^][v][top][bottom][index][help] */
root/fs/ubifs/lpt.c

DEFINITIONS
