linux/fs/ubifs/sb.c
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   1/*
   2 * This file is part of UBIFS.
   3 *
   4 * Copyright (C) 2006-2008 Nokia Corporation.
   5 *
   6 * This program is free software; you can redistribute it and/or modify it
   7 * under the terms of the GNU General Public License version 2 as published by
   8 * the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it will be useful, but WITHOUT
  11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13 * more details.
  14 *
  15 * You should have received a copy of the GNU General Public License along with
  16 * this program; if not, write to the Free Software Foundation, Inc., 51
  17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18 *
  19 * Authors: Artem Bityutskiy (Битюцкий Артём)
  20 *          Adrian Hunter
  21 */
  22
  23/*
  24 * This file implements UBIFS superblock. The superblock is stored at the first
  25 * LEB of the volume and is never changed by UBIFS. Only user-space tools may
  26 * change it. The superblock node mostly contains geometry information.
  27 */
  28
  29#include "ubifs.h"
  30#include <linux/slab.h>
  31#include <linux/random.h>
  32#include <linux/math64.h>
  33
  34/*
  35 * Default journal size in logical eraseblocks as a percent of total
  36 * flash size.
  37 */
  38#define DEFAULT_JNL_PERCENT 5
  39
  40/* Default maximum journal size in bytes */
  41#define DEFAULT_MAX_JNL (32*1024*1024)
  42
  43/* Default indexing tree fanout */
  44#define DEFAULT_FANOUT 8
  45
  46/* Default number of data journal heads */
  47#define DEFAULT_JHEADS_CNT 1
  48
  49/* Default positions of different LEBs in the main area */
  50#define DEFAULT_IDX_LEB  0
  51#define DEFAULT_DATA_LEB 1
  52#define DEFAULT_GC_LEB   2
  53
  54/* Default number of LEB numbers in LPT's save table */
  55#define DEFAULT_LSAVE_CNT 256
  56
  57/* Default reserved pool size as a percent of maximum free space */
  58#define DEFAULT_RP_PERCENT 5
  59
  60/* The default maximum size of reserved pool in bytes */
  61#define DEFAULT_MAX_RP_SIZE (5*1024*1024)
  62
  63/* Default time granularity in nanoseconds */
  64#define DEFAULT_TIME_GRAN 1000000000
  65
  66/**
  67 * create_default_filesystem - format empty UBI volume.
  68 * @c: UBIFS file-system description object
  69 *
  70 * This function creates default empty file-system. Returns zero in case of
  71 * success and a negative error code in case of failure.
  72 */
  73static int create_default_filesystem(struct ubifs_info *c)
  74{
  75        struct ubifs_sb_node *sup;
  76        struct ubifs_mst_node *mst;
  77        struct ubifs_idx_node *idx;
  78        struct ubifs_branch *br;
  79        struct ubifs_ino_node *ino;
  80        struct ubifs_cs_node *cs;
  81        union ubifs_key key;
  82        int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first;
  83        int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0;
  84        int min_leb_cnt = UBIFS_MIN_LEB_CNT;
  85        long long tmp64, main_bytes;
  86        __le64 tmp_le64;
  87
  88        /* Some functions called from here depend on the @c->key_len filed */
  89        c->key_len = UBIFS_SK_LEN;
  90
  91        /*
  92         * First of all, we have to calculate default file-system geometry -
  93         * log size, journal size, etc.
  94         */
  95        if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
  96                /* We can first multiply then divide and have no overflow */
  97                jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
  98        else
  99                jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;
 100
 101        if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
 102                jnl_lebs = UBIFS_MIN_JNL_LEBS;
 103        if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
 104                jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;
 105
 106        /*
 107         * The log should be large enough to fit reference nodes for all bud
 108         * LEBs. Because buds do not have to start from the beginning of LEBs
 109         * (half of the LEB may contain committed data), the log should
 110         * generally be larger, make it twice as large.
 111         */
 112        tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
 113        log_lebs = tmp / c->leb_size;
 114        /* Plus one LEB reserved for commit */
 115        log_lebs += 1;
 116        if (c->leb_cnt - min_leb_cnt > 8) {
 117                /* And some extra space to allow writes while committing */
 118                log_lebs += 1;
 119                min_leb_cnt += 1;
 120        }
 121
 122        max_buds = jnl_lebs - log_lebs;
 123        if (max_buds < UBIFS_MIN_BUD_LEBS)
 124                max_buds = UBIFS_MIN_BUD_LEBS;
 125
 126        /*
 127         * Orphan nodes are stored in a separate area. One node can store a lot
 128         * of orphan inode numbers, but when new orphan comes we just add a new
 129         * orphan node. At some point the nodes are consolidated into one
 130         * orphan node.
 131         */
 132        orph_lebs = UBIFS_MIN_ORPH_LEBS;
 133        if (c->leb_cnt - min_leb_cnt > 1)
 134                /*
 135                 * For debugging purposes it is better to have at least 2
 136                 * orphan LEBs, because the orphan subsystem would need to do
 137                 * consolidations and would be stressed more.
 138                 */
 139                orph_lebs += 1;
 140
 141        main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
 142        main_lebs -= orph_lebs;
 143
 144        lpt_first = UBIFS_LOG_LNUM + log_lebs;
 145        c->lsave_cnt = DEFAULT_LSAVE_CNT;
 146        c->max_leb_cnt = c->leb_cnt;
 147        err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
 148                                    &big_lpt);
 149        if (err)
 150                return err;
 151
 152        dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
 153                lpt_first + lpt_lebs - 1);
 154
 155        main_first = c->leb_cnt - main_lebs;
 156
 157        /* Create default superblock */
 158        tmp = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
 159        sup = kzalloc(tmp, GFP_KERNEL);
 160        if (!sup)
 161                return -ENOMEM;
 162
 163        tmp64 = (long long)max_buds * c->leb_size;
 164        if (big_lpt)
 165                sup_flags |= UBIFS_FLG_BIGLPT;
 166
 167        sup->ch.node_type  = UBIFS_SB_NODE;
 168        sup->key_hash      = UBIFS_KEY_HASH_R5;
 169        sup->flags         = cpu_to_le32(sup_flags);
 170        sup->min_io_size   = cpu_to_le32(c->min_io_size);
 171        sup->leb_size      = cpu_to_le32(c->leb_size);
 172        sup->leb_cnt       = cpu_to_le32(c->leb_cnt);
 173        sup->max_leb_cnt   = cpu_to_le32(c->max_leb_cnt);
 174        sup->max_bud_bytes = cpu_to_le64(tmp64);
 175        sup->log_lebs      = cpu_to_le32(log_lebs);
 176        sup->lpt_lebs      = cpu_to_le32(lpt_lebs);
 177        sup->orph_lebs     = cpu_to_le32(orph_lebs);
 178        sup->jhead_cnt     = cpu_to_le32(DEFAULT_JHEADS_CNT);
 179        sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);
 180        sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);
 181        sup->fmt_version   = cpu_to_le32(UBIFS_FORMAT_VERSION);
 182        sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);
 183        if (c->mount_opts.override_compr)
 184                sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
 185        else
 186                sup->default_compr = cpu_to_le16(UBIFS_COMPR_LZO);
 187
 188        generate_random_uuid(sup->uuid);
 189
 190        main_bytes = (long long)main_lebs * c->leb_size;
 191        tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
 192        if (tmp64 > DEFAULT_MAX_RP_SIZE)
 193                tmp64 = DEFAULT_MAX_RP_SIZE;
 194        sup->rp_size = cpu_to_le64(tmp64);
 195        sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
 196
 197        err = ubifs_write_node(c, sup, UBIFS_SB_NODE_SZ, 0, 0);
 198        kfree(sup);
 199        if (err)
 200                return err;
 201
 202        dbg_gen("default superblock created at LEB 0:0");
 203
 204        /* Create default master node */
 205        mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
 206        if (!mst)
 207                return -ENOMEM;
 208
 209        mst->ch.node_type = UBIFS_MST_NODE;
 210        mst->log_lnum     = cpu_to_le32(UBIFS_LOG_LNUM);
 211        mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO);
 212        mst->cmt_no       = 0;
 213        mst->root_lnum    = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
 214        mst->root_offs    = 0;
 215        tmp = ubifs_idx_node_sz(c, 1);
 216        mst->root_len     = cpu_to_le32(tmp);
 217        mst->gc_lnum      = cpu_to_le32(main_first + DEFAULT_GC_LEB);
 218        mst->ihead_lnum   = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
 219        mst->ihead_offs   = cpu_to_le32(ALIGN(tmp, c->min_io_size));
 220        mst->index_size   = cpu_to_le64(ALIGN(tmp, 8));
 221        mst->lpt_lnum     = cpu_to_le32(c->lpt_lnum);
 222        mst->lpt_offs     = cpu_to_le32(c->lpt_offs);
 223        mst->nhead_lnum   = cpu_to_le32(c->nhead_lnum);
 224        mst->nhead_offs   = cpu_to_le32(c->nhead_offs);
 225        mst->ltab_lnum    = cpu_to_le32(c->ltab_lnum);
 226        mst->ltab_offs    = cpu_to_le32(c->ltab_offs);
 227        mst->lsave_lnum   = cpu_to_le32(c->lsave_lnum);
 228        mst->lsave_offs   = cpu_to_le32(c->lsave_offs);
 229        mst->lscan_lnum   = cpu_to_le32(main_first);
 230        mst->empty_lebs   = cpu_to_le32(main_lebs - 2);
 231        mst->idx_lebs     = cpu_to_le32(1);
 232        mst->leb_cnt      = cpu_to_le32(c->leb_cnt);
 233
 234        /* Calculate lprops statistics */
 235        tmp64 = main_bytes;
 236        tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
 237        tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
 238        mst->total_free = cpu_to_le64(tmp64);
 239
 240        tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
 241        ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) -
 242                          UBIFS_INO_NODE_SZ;
 243        tmp64 += ino_waste;
 244        tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8);
 245        mst->total_dirty = cpu_to_le64(tmp64);
 246
 247        /*  The indexing LEB does not contribute to dark space */
 248        tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm);
 249        mst->total_dark = cpu_to_le64(tmp64);
 250
 251        mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
 252
 253        err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0);
 254        if (err) {
 255                kfree(mst);
 256                return err;
 257        }
 258        err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
 259                               0);
 260        kfree(mst);
 261        if (err)
 262                return err;
 263
 264        dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
 265
 266        /* Create the root indexing node */
 267        tmp = ubifs_idx_node_sz(c, 1);
 268        idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
 269        if (!idx)
 270                return -ENOMEM;
 271
 272        c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
 273        c->key_hash = key_r5_hash;
 274
 275        idx->ch.node_type = UBIFS_IDX_NODE;
 276        idx->child_cnt = cpu_to_le16(1);
 277        ino_key_init(c, &key, UBIFS_ROOT_INO);
 278        br = ubifs_idx_branch(c, idx, 0);
 279        key_write_idx(c, &key, &br->key);
 280        br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
 281        br->len  = cpu_to_le32(UBIFS_INO_NODE_SZ);
 282        err = ubifs_write_node(c, idx, tmp, main_first + DEFAULT_IDX_LEB, 0);
 283        kfree(idx);
 284        if (err)
 285                return err;
 286
 287        dbg_gen("default root indexing node created LEB %d:0",
 288                main_first + DEFAULT_IDX_LEB);
 289
 290        /* Create default root inode */
 291        tmp = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
 292        ino = kzalloc(tmp, GFP_KERNEL);
 293        if (!ino)
 294                return -ENOMEM;
 295
 296        ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
 297        ino->ch.node_type = UBIFS_INO_NODE;
 298        ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
 299        ino->nlink = cpu_to_le32(2);
 300        tmp_le64 = cpu_to_le64(CURRENT_TIME_SEC.tv_sec);
 301        ino->atime_sec   = tmp_le64;
 302        ino->ctime_sec   = tmp_le64;
 303        ino->mtime_sec   = tmp_le64;
 304        ino->atime_nsec  = 0;
 305        ino->ctime_nsec  = 0;
 306        ino->mtime_nsec  = 0;
 307        ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
 308        ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
 309
 310        /* Set compression enabled by default */
 311        ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
 312
 313        err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
 314                               main_first + DEFAULT_DATA_LEB, 0);
 315        kfree(ino);
 316        if (err)
 317                return err;
 318
 319        dbg_gen("root inode created at LEB %d:0",
 320                main_first + DEFAULT_DATA_LEB);
 321
 322        /*
 323         * The first node in the log has to be the commit start node. This is
 324         * always the case during normal file-system operation. Write a fake
 325         * commit start node to the log.
 326         */
 327        tmp = ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size);
 328        cs = kzalloc(tmp, GFP_KERNEL);
 329        if (!cs)
 330                return -ENOMEM;
 331
 332        cs->ch.node_type = UBIFS_CS_NODE;
 333        err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
 334        kfree(cs);
 335
 336        ubifs_msg("default file-system created");
 337        return 0;
 338}
 339
 340/**
 341 * validate_sb - validate superblock node.
 342 * @c: UBIFS file-system description object
 343 * @sup: superblock node
 344 *
 345 * This function validates superblock node @sup. Since most of data was read
 346 * from the superblock and stored in @c, the function validates fields in @c
 347 * instead. Returns zero in case of success and %-EINVAL in case of validation
 348 * failure.
 349 */
 350static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
 351{
 352        long long max_bytes;
 353        int err = 1, min_leb_cnt;
 354
 355        if (!c->key_hash) {
 356                err = 2;
 357                goto failed;
 358        }
 359
 360        if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
 361                err = 3;
 362                goto failed;
 363        }
 364
 365        if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
 366                ubifs_err("min. I/O unit mismatch: %d in superblock, %d real",
 367                          le32_to_cpu(sup->min_io_size), c->min_io_size);
 368                goto failed;
 369        }
 370
 371        if (le32_to_cpu(sup->leb_size) != c->leb_size) {
 372                ubifs_err("LEB size mismatch: %d in superblock, %d real",
 373                          le32_to_cpu(sup->leb_size), c->leb_size);
 374                goto failed;
 375        }
 376
 377        if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
 378            c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
 379            c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
 380            c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
 381                err = 4;
 382                goto failed;
 383        }
 384
 385        /*
 386         * Calculate minimum allowed amount of main area LEBs. This is very
 387         * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
 388         * have just read from the superblock.
 389         */
 390        min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
 391        min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;
 392
 393        if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
 394                ubifs_err("bad LEB count: %d in superblock, %d on UBI volume, "
 395                          "%d minimum required", c->leb_cnt, c->vi.size,
 396                          min_leb_cnt);
 397                goto failed;
 398        }
 399
 400        if (c->max_leb_cnt < c->leb_cnt) {
 401                ubifs_err("max. LEB count %d less than LEB count %d",
 402                          c->max_leb_cnt, c->leb_cnt);
 403                goto failed;
 404        }
 405
 406        if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
 407                ubifs_err("too few main LEBs count %d, must be at least %d",
 408                          c->main_lebs, UBIFS_MIN_MAIN_LEBS);
 409                goto failed;
 410        }
 411
 412        max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
 413        if (c->max_bud_bytes < max_bytes) {
 414                ubifs_err("too small journal (%lld bytes), must be at least "
 415                          "%lld bytes",  c->max_bud_bytes, max_bytes);
 416                goto failed;
 417        }
 418
 419        max_bytes = (long long)c->leb_size * c->main_lebs;
 420        if (c->max_bud_bytes > max_bytes) {
 421                ubifs_err("too large journal size (%lld bytes), only %lld bytes"
 422                          "available in the main area",
 423                          c->max_bud_bytes, max_bytes);
 424                goto failed;
 425        }
 426
 427        if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
 428            c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
 429                err = 9;
 430                goto failed;
 431        }
 432
 433        if (c->fanout < UBIFS_MIN_FANOUT ||
 434            ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
 435                err = 10;
 436                goto failed;
 437        }
 438
 439        if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
 440            c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
 441            c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
 442                err = 11;
 443                goto failed;
 444        }
 445
 446        if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
 447            c->orph_lebs + c->main_lebs != c->leb_cnt) {
 448                err = 12;
 449                goto failed;
 450        }
 451
 452        if (c->default_compr < 0 || c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
 453                err = 13;
 454                goto failed;
 455        }
 456
 457        if (c->rp_size < 0 || max_bytes < c->rp_size) {
 458                err = 14;
 459                goto failed;
 460        }
 461
 462        if (le32_to_cpu(sup->time_gran) > 1000000000 ||
 463            le32_to_cpu(sup->time_gran) < 1) {
 464                err = 15;
 465                goto failed;
 466        }
 467
 468        return 0;
 469
 470failed:
 471        ubifs_err("bad superblock, error %d", err);
 472        ubifs_dump_node(c, sup);
 473        return -EINVAL;
 474}
 475
 476/**
 477 * ubifs_read_sb_node - read superblock node.
 478 * @c: UBIFS file-system description object
 479 *
 480 * This function returns a pointer to the superblock node or a negative error
 481 * code. Note, the user of this function is responsible of kfree()'ing the
 482 * returned superblock buffer.
 483 */
 484struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
 485{
 486        struct ubifs_sb_node *sup;
 487        int err;
 488
 489        sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
 490        if (!sup)
 491                return ERR_PTR(-ENOMEM);
 492
 493        err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
 494                              UBIFS_SB_LNUM, 0);
 495        if (err) {
 496                kfree(sup);
 497                return ERR_PTR(err);
 498        }
 499
 500        return sup;
 501}
 502
 503/**
 504 * ubifs_write_sb_node - write superblock node.
 505 * @c: UBIFS file-system description object
 506 * @sup: superblock node read with 'ubifs_read_sb_node()'
 507 *
 508 * This function returns %0 on success and a negative error code on failure.
 509 */
 510int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
 511{
 512        int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
 513
 514        ubifs_prepare_node(c, sup, UBIFS_SB_NODE_SZ, 1);
 515        return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
 516}
 517
 518/**
 519 * ubifs_read_superblock - read superblock.
 520 * @c: UBIFS file-system description object
 521 *
 522 * This function finds, reads and checks the superblock. If an empty UBI volume
 523 * is being mounted, this function creates default superblock. Returns zero in
 524 * case of success, and a negative error code in case of failure.
 525 */
 526int ubifs_read_superblock(struct ubifs_info *c)
 527{
 528        int err, sup_flags;
 529        struct ubifs_sb_node *sup;
 530
 531        if (c->empty) {
 532                err = create_default_filesystem(c);
 533                if (err)
 534                        return err;
 535        }
 536
 537        sup = ubifs_read_sb_node(c);
 538        if (IS_ERR(sup))
 539                return PTR_ERR(sup);
 540
 541        c->fmt_version = le32_to_cpu(sup->fmt_version);
 542        c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);
 543
 544        /*
 545         * The software supports all previous versions but not future versions,
 546         * due to the unavailability of time-travelling equipment.
 547         */
 548        if (c->fmt_version > UBIFS_FORMAT_VERSION) {
 549                ubifs_assert(!c->ro_media || c->ro_mount);
 550                if (!c->ro_mount ||
 551                    c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
 552                        ubifs_err("on-flash format version is w%d/r%d, but "
 553                                  "software only supports up to version "
 554                                  "w%d/r%d", c->fmt_version,
 555                                  c->ro_compat_version, UBIFS_FORMAT_VERSION,
 556                                  UBIFS_RO_COMPAT_VERSION);
 557                        if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
 558                                ubifs_msg("only R/O mounting is possible");
 559                                err = -EROFS;
 560                        } else
 561                                err = -EINVAL;
 562                        goto out;
 563                }
 564
 565                /*
 566                 * The FS is mounted R/O, and the media format is
 567                 * R/O-compatible with the UBIFS implementation, so we can
 568                 * mount.
 569                 */
 570                c->rw_incompat = 1;
 571        }
 572
 573        if (c->fmt_version < 3) {
 574                ubifs_err("on-flash format version %d is not supported",
 575                          c->fmt_version);
 576                err = -EINVAL;
 577                goto out;
 578        }
 579
 580        switch (sup->key_hash) {
 581        case UBIFS_KEY_HASH_R5:
 582                c->key_hash = key_r5_hash;
 583                c->key_hash_type = UBIFS_KEY_HASH_R5;
 584                break;
 585
 586        case UBIFS_KEY_HASH_TEST:
 587                c->key_hash = key_test_hash;
 588                c->key_hash_type = UBIFS_KEY_HASH_TEST;
 589                break;
 590        };
 591
 592        c->key_fmt = sup->key_fmt;
 593
 594        switch (c->key_fmt) {
 595        case UBIFS_SIMPLE_KEY_FMT:
 596                c->key_len = UBIFS_SK_LEN;
 597                break;
 598        default:
 599                ubifs_err("unsupported key format");
 600                err = -EINVAL;
 601                goto out;
 602        }
 603
 604        c->leb_cnt       = le32_to_cpu(sup->leb_cnt);
 605        c->max_leb_cnt   = le32_to_cpu(sup->max_leb_cnt);
 606        c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
 607        c->log_lebs      = le32_to_cpu(sup->log_lebs);
 608        c->lpt_lebs      = le32_to_cpu(sup->lpt_lebs);
 609        c->orph_lebs     = le32_to_cpu(sup->orph_lebs);
 610        c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
 611        c->fanout        = le32_to_cpu(sup->fanout);
 612        c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
 613        c->rp_size       = le64_to_cpu(sup->rp_size);
 614        c->rp_uid        = le32_to_cpu(sup->rp_uid);
 615        c->rp_gid        = le32_to_cpu(sup->rp_gid);
 616        sup_flags        = le32_to_cpu(sup->flags);
 617        if (!c->mount_opts.override_compr)
 618                c->default_compr = le16_to_cpu(sup->default_compr);
 619
 620        c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
 621        memcpy(&c->uuid, &sup->uuid, 16);
 622        c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
 623        c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
 624
 625        /* Automatically increase file system size to the maximum size */
 626        c->old_leb_cnt = c->leb_cnt;
 627        if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
 628                c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
 629                if (c->ro_mount)
 630                        dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs",
 631                                c->old_leb_cnt, c->leb_cnt);
 632                else {
 633                        dbg_mnt("Auto resizing (sb) from %d LEBs to %d LEBs",
 634                                c->old_leb_cnt, c->leb_cnt);
 635                        sup->leb_cnt = cpu_to_le32(c->leb_cnt);
 636                        err = ubifs_write_sb_node(c, sup);
 637                        if (err)
 638                                goto out;
 639                        c->old_leb_cnt = c->leb_cnt;
 640                }
 641        }
 642
 643        c->log_bytes = (long long)c->log_lebs * c->leb_size;
 644        c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
 645        c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
 646        c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
 647        c->orph_first = c->lpt_last + 1;
 648        c->orph_last = c->orph_first + c->orph_lebs - 1;
 649        c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
 650        c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
 651        c->main_first = c->leb_cnt - c->main_lebs;
 652
 653        err = validate_sb(c, sup);
 654out:
 655        kfree(sup);
 656        return err;
 657}
 658
 659/**
 660 * fixup_leb - fixup/unmap an LEB containing free space.
 661 * @c: UBIFS file-system description object
 662 * @lnum: the LEB number to fix up
 663 * @len: number of used bytes in LEB (starting at offset 0)
 664 *
 665 * This function reads the contents of the given LEB number @lnum, then fixes
 666 * it up, so that empty min. I/O units in the end of LEB are actually erased on
 667 * flash (rather than being just all-0xff real data). If the LEB is completely
 668 * empty, it is simply unmapped.
 669 */
 670static int fixup_leb(struct ubifs_info *c, int lnum, int len)
 671{
 672        int err;
 673
 674        ubifs_assert(len >= 0);
 675        ubifs_assert(len % c->min_io_size == 0);
 676        ubifs_assert(len < c->leb_size);
 677
 678        if (len == 0) {
 679                dbg_mnt("unmap empty LEB %d", lnum);
 680                return ubifs_leb_unmap(c, lnum);
 681        }
 682
 683        dbg_mnt("fixup LEB %d, data len %d", lnum, len);
 684        err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
 685        if (err)
 686                return err;
 687
 688        return ubifs_leb_change(c, lnum, c->sbuf, len);
 689}
 690
 691/**
 692 * fixup_free_space - find & remap all LEBs containing free space.
 693 * @c: UBIFS file-system description object
 694 *
 695 * This function walks through all LEBs in the filesystem and fiexes up those
 696 * containing free/empty space.
 697 */
 698static int fixup_free_space(struct ubifs_info *c)
 699{
 700        int lnum, err = 0;
 701        struct ubifs_lprops *lprops;
 702
 703        ubifs_get_lprops(c);
 704
 705        /* Fixup LEBs in the master area */
 706        for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
 707                err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
 708                if (err)
 709                        goto out;
 710        }
 711
 712        /* Unmap unused log LEBs */
 713        lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
 714        while (lnum != c->ltail_lnum) {
 715                err = fixup_leb(c, lnum, 0);
 716                if (err)
 717                        goto out;
 718                lnum = ubifs_next_log_lnum(c, lnum);
 719        }
 720
 721        /*
 722         * Fixup the log head which contains the only a CS node at the
 723         * beginning.
 724         */
 725        err = fixup_leb(c, c->lhead_lnum,
 726                        ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size));
 727        if (err)
 728                goto out;
 729
 730        /* Fixup LEBs in the LPT area */
 731        for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
 732                int free = c->ltab[lnum - c->lpt_first].free;
 733
 734                if (free > 0) {
 735                        err = fixup_leb(c, lnum, c->leb_size - free);
 736                        if (err)
 737                                goto out;
 738                }
 739        }
 740
 741        /* Unmap LEBs in the orphans area */
 742        for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
 743                err = fixup_leb(c, lnum, 0);
 744                if (err)
 745                        goto out;
 746        }
 747
 748        /* Fixup LEBs in the main area */
 749        for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
 750                lprops = ubifs_lpt_lookup(c, lnum);
 751                if (IS_ERR(lprops)) {
 752                        err = PTR_ERR(lprops);
 753                        goto out;
 754                }
 755
 756                if (lprops->free > 0) {
 757                        err = fixup_leb(c, lnum, c->leb_size - lprops->free);
 758                        if (err)
 759                                goto out;
 760                }
 761        }
 762
 763out:
 764        ubifs_release_lprops(c);
 765        return err;
 766}
 767
 768/**
 769 * ubifs_fixup_free_space - find & fix all LEBs with free space.
 770 * @c: UBIFS file-system description object
 771 *
 772 * This function fixes up LEBs containing free space on first mount, if the
 773 * appropriate flag was set when the FS was created. Each LEB with one or more
 774 * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
 775 * the free space is actually erased. E.g., this is necessary for some NAND
 776 * chips, since the free space may have been programmed like real "0xff" data
 777 * (generating a non-0xff ECC), causing future writes to the not-really-erased
 778 * NAND pages to behave badly. After the space is fixed up, the superblock flag
 779 * is cleared, so that this is skipped for all future mounts.
 780 */
 781int ubifs_fixup_free_space(struct ubifs_info *c)
 782{
 783        int err;
 784        struct ubifs_sb_node *sup;
 785
 786        ubifs_assert(c->space_fixup);
 787        ubifs_assert(!c->ro_mount);
 788
 789        ubifs_msg("start fixing up free space");
 790
 791        err = fixup_free_space(c);
 792        if (err)
 793                return err;
 794
 795        sup = ubifs_read_sb_node(c);
 796        if (IS_ERR(sup))
 797                return PTR_ERR(sup);
 798
 799        /* Free-space fixup is no longer required */
 800        c->space_fixup = 0;
 801        sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);
 802
 803        err = ubifs_write_sb_node(c, sup);
 804        kfree(sup);
 805        if (err)
 806                return err;
 807
 808        ubifs_msg("free space fixup complete");
 809        return err;
 810}
 811
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