fs/ubifs/master.c

   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  */
  36 static 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
  80 out:
  81         ubifs_scan_destroy(sleb);
  82         return -EUCLEAN;
  83
  84 out_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  */
  98 static 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->old_idx_sz & 7 || c->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->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
 242 out:
 243         ubifs_err("bad master node at offset %d error %d", c->mst_offs, err);
 244         dbg_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  */
 256 int 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->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->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                         dbg_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  */
 360 int 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, UBI_SHORTTERM);
 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, UBI_SHORTTERM);
 394
 395         return err;
 396 }