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