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