linux/fs/ubifs/master.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/* This file implements reading and writing the master node */
  24
  25#include "ubifs.h"
  26
  27/**
  28 * scan_for_master - search the valid master node.
  29 * @c: UBIFS file-system description object
  30 *
  31 * This function scans the master node LEBs and search for the latest master
  32 * node. Returns zero in case of success, %-EUCLEAN if there master area is
  33 * corrupted and requires recovery, and a negative error code in case of
  34 * failure.
  35 */
  36static int scan_for_master(struct ubifs_info *c)
  37{
  38        struct ubifs_scan_leb *sleb;
  39        struct ubifs_scan_node *snod;
  40        int lnum, offs = 0, nodes_cnt;
  41
  42        lnum = UBIFS_MST_LNUM;
  43
  44        sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
  45        if (IS_ERR(sleb))
  46                return PTR_ERR(sleb);
  47        nodes_cnt = sleb->nodes_cnt;
  48        if (nodes_cnt > 0) {
  49                snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
  50                                  list);
  51                if (snod->type != UBIFS_MST_NODE)
  52                        goto out_dump;
  53                memcpy(c->mst_node, snod->node, snod->len);
  54                offs = snod->offs;
  55        }
  56        ubifs_scan_destroy(sleb);
  57
  58        lnum += 1;
  59
  60        sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
  61        if (IS_ERR(sleb))
  62                return PTR_ERR(sleb);
  63        if (sleb->nodes_cnt != nodes_cnt)
  64                goto out;
  65        if (!sleb->nodes_cnt)
  66                goto out;
  67        snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
  68        if (snod->type != UBIFS_MST_NODE)
  69                goto out_dump;
  70        if (snod->offs != offs)
  71                goto out;
  72        if (memcmp((void *)c->mst_node + UBIFS_CH_SZ,
  73                   (void *)snod->node + UBIFS_CH_SZ,
  74                   UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
  75                goto out;
  76        c->mst_offs = offs;
  77        ubifs_scan_destroy(sleb);
  78        return 0;
  79
  80out:
  81        ubifs_scan_destroy(sleb);
  82        return -EUCLEAN;
  83
  84out_dump:
  85        ubifs_err("unexpected node type %d master LEB %d:%d",
  86                  snod->type, lnum, snod->offs);
  87        ubifs_scan_destroy(sleb);
  88        return -EINVAL;
  89}
  90
  91/**
  92 * validate_master - validate master node.
  93 * @c: UBIFS file-system description object
  94 *
  95 * This function validates data which was read from master node. Returns zero
  96 * if the data is all right and %-EINVAL if not.
  97 */
  98static int validate_master(const struct ubifs_info *c)
  99{
 100        long long main_sz;
 101        int err;
 102
 103        if (c->max_sqnum >= SQNUM_WATERMARK) {
 104                err = 1;
 105                goto out;
 106        }
 107
 108        if (c->cmt_no >= c->max_sqnum) {
 109                err = 2;
 110                goto out;
 111        }
 112
 113        if (c->highest_inum >= INUM_WATERMARK) {
 114                err = 3;
 115                goto out;
 116        }
 117
 118        if (c->lhead_lnum < UBIFS_LOG_LNUM ||
 119            c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
 120            c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
 121            c->lhead_offs & (c->min_io_size - 1)) {
 122                err = 4;
 123                goto out;
 124        }
 125
 126        if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
 127            c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
 128                err = 5;
 129                goto out;
 130        }
 131
 132        if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
 133            c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
 134                err = 6;
 135                goto out;
 136        }
 137
 138        if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
 139                err = 7;
 140                goto out;
 141        }
 142
 143        if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
 144            c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
 145            c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
 146                err = 8;
 147                goto out;
 148        }
 149
 150        main_sz = (long long)c->main_lebs * c->leb_size;
 151        if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
 152                err = 9;
 153                goto out;
 154        }
 155
 156        if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
 157            c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
 158                err = 10;
 159                goto out;
 160        }
 161
 162        if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
 163            c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
 164            c->nhead_offs > c->leb_size) {
 165                err = 11;
 166                goto out;
 167        }
 168
 169        if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
 170            c->ltab_offs < 0 ||
 171            c->ltab_offs + c->ltab_sz > c->leb_size) {
 172                err = 12;
 173                goto out;
 174        }
 175
 176        if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
 177            c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
 178            c->lsave_offs + c->lsave_sz > c->leb_size)) {
 179                err = 13;
 180                goto out;
 181        }
 182
 183        if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
 184                err = 14;
 185                goto out;
 186        }
 187
 188        if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
 189                err = 15;
 190                goto out;
 191        }
 192
 193        if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
 194                err = 16;
 195                goto out;
 196        }
 197
 198        if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
 199            c->lst.total_free & 7) {
 200                err = 17;
 201                goto out;
 202        }
 203
 204        if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
 205                err = 18;
 206                goto out;
 207        }
 208
 209        if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
 210                err = 19;
 211                goto out;
 212        }
 213
 214        if (c->lst.total_free + c->lst.total_dirty +
 215            c->lst.total_used > main_sz) {
 216                err = 20;
 217                goto out;
 218        }
 219
 220        if (c->lst.total_dead + c->lst.total_dark +
 221            c->lst.total_used + c->bi.old_idx_sz > main_sz) {
 222                err = 21;
 223                goto out;
 224        }
 225
 226        if (c->lst.total_dead < 0 ||
 227            c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
 228            c->lst.total_dead & 7) {
 229                err = 22;
 230                goto out;
 231        }
 232
 233        if (c->lst.total_dark < 0 ||
 234            c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
 235            c->lst.total_dark & 7) {
 236                err = 23;
 237                goto out;
 238        }
 239
 240        return 0;
 241
 242out:
 243        ubifs_err("bad master node at offset %d error %d", c->mst_offs, err);
 244        ubifs_dump_node(c, c->mst_node);
 245        return -EINVAL;
 246}
 247
 248/**
 249 * ubifs_read_master - read master node.
 250 * @c: UBIFS file-system description object
 251 *
 252 * This function finds and reads the master node during file-system mount. If
 253 * the flash is empty, it creates default master node as well. Returns zero in
 254 * case of success and a negative error code in case of failure.
 255 */
 256int ubifs_read_master(struct ubifs_info *c)
 257{
 258        int err, old_leb_cnt;
 259
 260        c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
 261        if (!c->mst_node)
 262                return -ENOMEM;
 263
 264        err = scan_for_master(c);
 265        if (err) {
 266                if (err == -EUCLEAN)
 267                        err = ubifs_recover_master_node(c);
 268                if (err)
 269                        /*
 270                         * Note, we do not free 'c->mst_node' here because the
 271                         * unmount routine will take care of this.
 272                         */
 273                        return err;
 274        }
 275
 276        /* Make sure that the recovery flag is clear */
 277        c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
 278
 279        c->max_sqnum       = le64_to_cpu(c->mst_node->ch.sqnum);
 280        c->highest_inum    = le64_to_cpu(c->mst_node->highest_inum);
 281        c->cmt_no          = le64_to_cpu(c->mst_node->cmt_no);
 282        c->zroot.lnum      = le32_to_cpu(c->mst_node->root_lnum);
 283        c->zroot.offs      = le32_to_cpu(c->mst_node->root_offs);
 284        c->zroot.len       = le32_to_cpu(c->mst_node->root_len);
 285        c->lhead_lnum      = le32_to_cpu(c->mst_node->log_lnum);
 286        c->gc_lnum         = le32_to_cpu(c->mst_node->gc_lnum);
 287        c->ihead_lnum      = le32_to_cpu(c->mst_node->ihead_lnum);
 288        c->ihead_offs      = le32_to_cpu(c->mst_node->ihead_offs);
 289        c->bi.old_idx_sz   = le64_to_cpu(c->mst_node->index_size);
 290        c->lpt_lnum        = le32_to_cpu(c->mst_node->lpt_lnum);
 291        c->lpt_offs        = le32_to_cpu(c->mst_node->lpt_offs);
 292        c->nhead_lnum      = le32_to_cpu(c->mst_node->nhead_lnum);
 293        c->nhead_offs      = le32_to_cpu(c->mst_node->nhead_offs);
 294        c->ltab_lnum       = le32_to_cpu(c->mst_node->ltab_lnum);
 295        c->ltab_offs       = le32_to_cpu(c->mst_node->ltab_offs);
 296        c->lsave_lnum      = le32_to_cpu(c->mst_node->lsave_lnum);
 297        c->lsave_offs      = le32_to_cpu(c->mst_node->lsave_offs);
 298        c->lscan_lnum      = le32_to_cpu(c->mst_node->lscan_lnum);
 299        c->lst.empty_lebs  = le32_to_cpu(c->mst_node->empty_lebs);
 300        c->lst.idx_lebs    = le32_to_cpu(c->mst_node->idx_lebs);
 301        old_leb_cnt        = le32_to_cpu(c->mst_node->leb_cnt);
 302        c->lst.total_free  = le64_to_cpu(c->mst_node->total_free);
 303        c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
 304        c->lst.total_used  = le64_to_cpu(c->mst_node->total_used);
 305        c->lst.total_dead  = le64_to_cpu(c->mst_node->total_dead);
 306        c->lst.total_dark  = le64_to_cpu(c->mst_node->total_dark);
 307
 308        c->calc_idx_sz = c->bi.old_idx_sz;
 309
 310        if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
 311                c->no_orphs = 1;
 312
 313        if (old_leb_cnt != c->leb_cnt) {
 314                /* The file system has been resized */
 315                int growth = c->leb_cnt - old_leb_cnt;
 316
 317                if (c->leb_cnt < old_leb_cnt ||
 318                    c->leb_cnt < UBIFS_MIN_LEB_CNT) {
 319                        ubifs_err("bad leb_cnt on master node");
 320                        ubifs_dump_node(c, c->mst_node);
 321                        return -EINVAL;
 322                }
 323
 324                dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
 325                        old_leb_cnt, c->leb_cnt);
 326                c->lst.empty_lebs += growth;
 327                c->lst.total_free += growth * (long long)c->leb_size;
 328                c->lst.total_dark += growth * (long long)c->dark_wm;
 329
 330                /*
 331                 * Reflect changes back onto the master node. N.B. the master
 332                 * node gets written immediately whenever mounting (or
 333                 * remounting) in read-write mode, so we do not need to write it
 334                 * here.
 335                 */
 336                c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
 337                c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
 338                c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
 339                c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
 340        }
 341
 342        err = validate_master(c);
 343        if (err)
 344                return err;
 345
 346        err = dbg_old_index_check_init(c, &c->zroot);
 347
 348        return err;
 349}
 350
 351/**
 352 * ubifs_write_master - write master node.
 353 * @c: UBIFS file-system description object
 354 *
 355 * This function writes the master node. The caller has to take the
 356 * @c->mst_mutex lock before calling this function. Returns zero in case of
 357 * success and a negative error code in case of failure. The master node is
 358 * written twice to enable recovery.
 359 */
 360int ubifs_write_master(struct ubifs_info *c)
 361{
 362        int err, lnum, offs, len;
 363
 364        ubifs_assert(!c->ro_media && !c->ro_mount);
 365        if (c->ro_error)
 366                return -EROFS;
 367
 368        lnum = UBIFS_MST_LNUM;
 369        offs = c->mst_offs + c->mst_node_alsz;
 370        len = UBIFS_MST_NODE_SZ;
 371
 372        if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
 373                err = ubifs_leb_unmap(c, lnum);
 374                if (err)
 375                        return err;
 376                offs = 0;
 377        }
 378
 379        c->mst_offs = offs;
 380        c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
 381
 382        err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
 383        if (err)
 384                return err;
 385
 386        lnum += 1;
 387
 388        if (offs == 0) {
 389                err = ubifs_leb_unmap(c, lnum);
 390                if (err)
 391                        return err;
 392        }
 393        err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
 394
 395        return err;
 396}
 397
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