root/fs/ext2/super.c

/* [previous][next][first][last][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. ext2_error
  2. ext2_panic
  3. ext2_warning
  4. ext2_put_super
  5. parse_options
  6. ext2_setup_super
  7. ext2_check_descriptors
  8. ext2_read_super
  9. ext2_commit_super
  10. ext2_write_super
  11. ext2_remount
  12. ext2_statfs

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  */
  15 
  16 #include <stdarg.h>
  17 
  18 #include <asm/bitops.h>
  19 #include <asm/segment.h>
  20 #include <asm/system.h>
  21 
  22 #include <linux/errno.h>
  23 #include <linux/fs.h>
  24 #include <linux/ext2_fs.h>
  25 #include <linux/malloc.h>
  26 #include <linux/sched.h>
  27 #include <linux/stat.h>
  28 #include <linux/string.h>
  29 #include <linux/locks.h>
  30 
  31 static char error_buf[1024];
  32 
  33 void ext2_error (struct super_block * sb, const char * function,
     /* [previous][next][first][last][top][bottom][index][help] */
  34                  const char * fmt, ...)
  35 {
  36         va_list args;
  37 
  38         if (!(sb->s_flags & MS_RDONLY)) {
  39                 sb->u.ext2_sb.s_mount_state |= EXT2_ERROR_FS;
  40                 sb->u.ext2_sb.s_es->s_state |= EXT2_ERROR_FS;
  41                 mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
  42                 sb->s_dirt = 1;
  43         }
  44         va_start (args, fmt);
  45         vsprintf (error_buf, fmt, args);
  46         va_end (args);
  47         if (test_opt (sb, ERRORS_PANIC) ||
  48             (sb->u.ext2_sb.s_es->s_errors == EXT2_ERRORS_PANIC &&
  49              !test_opt (sb, ERRORS_CONT) && !test_opt (sb, ERRORS_RO)))
  50                 panic ("EXT2-fs panic (device %d/%d): %s: %s\n",
  51                        MAJOR(sb->s_dev), MINOR(sb->s_dev), function, error_buf);
  52         printk (KERN_CRIT "EXT2-fs error (device %d/%d): %s: %s\n",
  53                 MAJOR(sb->s_dev), MINOR(sb->s_dev), function, error_buf);
  54         if (test_opt (sb, ERRORS_RO) ||
  55             (sb->u.ext2_sb.s_es->s_errors == EXT2_ERRORS_RO &&
  56              !test_opt (sb, ERRORS_CONT) && !test_opt (sb, ERRORS_PANIC))) {
  57                 printk ("Remounting filesystem read-only\n");
  58                 sb->s_flags |= MS_RDONLY;
  59         }
  60 }
  61 
  62 NORET_TYPE void ext2_panic (struct super_block * sb, const char * function,
     /* [previous][next][first][last][top][bottom][index][help] */
  63                             const char * fmt, ...)
  64 {
  65         va_list args;
  66 
  67         if (!(sb->s_flags & MS_RDONLY)) {
  68                 sb->u.ext2_sb.s_mount_state |= EXT2_ERROR_FS;
  69                 sb->u.ext2_sb.s_es->s_state |= EXT2_ERROR_FS;
  70                 mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
  71                 sb->s_dirt = 1;
  72         }
  73         va_start (args, fmt);
  74         vsprintf (error_buf, fmt, args);
  75         va_end (args);
  76         panic ("EXT2-fs panic (device %d/%d): %s: %s\n",
  77                MAJOR(sb->s_dev), MINOR(sb->s_dev), function, error_buf);
  78 }
  79 
  80 void ext2_warning (struct super_block * sb, const char * function,
     /* [previous][next][first][last][top][bottom][index][help] */
  81                    const char * fmt, ...)
  82 {
  83         va_list args;
  84 
  85         va_start (args, fmt);
  86         vsprintf (error_buf, fmt, args);
  87         va_end (args);
  88         printk (KERN_WARNING "EXT2-fs warning (device %d/%d): %s: %s\n",
  89                 MAJOR(sb->s_dev), MINOR(sb->s_dev), function, error_buf);
  90 }
  91 
  92 void ext2_put_super (struct super_block * sb)
     /* [previous][next][first][last][top][bottom][index][help] */
  93 {
  94         int db_count;
  95         int i;
  96 
  97         lock_super (sb);
  98         if (!(sb->s_flags & MS_RDONLY)) {
  99                 sb->u.ext2_sb.s_es->s_state = sb->u.ext2_sb.s_mount_state;
 100                 mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
 101         }
 102         sb->s_dev = 0;
 103         db_count = sb->u.ext2_sb.s_db_per_group;
 104         for (i = 0; i < db_count; i++)
 105                 if (sb->u.ext2_sb.s_group_desc[i])
 106                         brelse (sb->u.ext2_sb.s_group_desc[i]);
 107         kfree_s (sb->u.ext2_sb.s_group_desc,
 108                  db_count * sizeof (struct buffer_head *));
 109         for (i = 0; i < EXT2_MAX_GROUP_LOADED; i++)
 110                 if (sb->u.ext2_sb.s_inode_bitmap[i])
 111                         brelse (sb->u.ext2_sb.s_inode_bitmap[i]);
 112         for (i = 0; i < EXT2_MAX_GROUP_LOADED; i++)
 113                 if (sb->u.ext2_sb.s_block_bitmap[i])
 114                         brelse (sb->u.ext2_sb.s_block_bitmap[i]);
 115         brelse (sb->u.ext2_sb.s_sbh);
 116         unlock_super (sb);
 117         return;
 118 }
 119 
 120 static struct super_operations ext2_sops = { 
 121         ext2_read_inode,
 122         NULL,
 123         ext2_write_inode,
 124         ext2_put_inode,
 125         ext2_put_super,
 126         ext2_write_super,
 127         ext2_statfs,
 128         ext2_remount
 129 };
 130 
 131 /*
 132  * This function has been shamelessly adapted from the msdos fs
 133  */
 134 static int parse_options (char * options, unsigned long * sb_block,
     /* [previous][next][first][last][top][bottom][index][help] */
 135                           unsigned short *resuid, unsigned short * resgid,
 136                           unsigned long * mount_options)
 137 {
 138         char * this_char;
 139         char * value;
 140 
 141         if (!options)
 142                 return 1;
 143         for (this_char = strtok (options, ",");
 144              this_char != NULL;
 145              this_char = strtok (NULL, ",")) {
 146                 if ((value = strchr (this_char, '=')) != NULL)
 147                         *value++ = 0;
 148                 if (!strcmp (this_char, "bsddf"))
 149                         clear_opt (*mount_options, MINIX_DF);
 150                 else if (!strcmp (this_char, "check")) {
 151                         if (!value || !*value)
 152                                 set_opt (*mount_options, CHECK_NORMAL);
 153                         else if (!strcmp (value, "none")) {
 154                                 clear_opt (*mount_options, CHECK_NORMAL);
 155                                 clear_opt (*mount_options, CHECK_STRICT);
 156                         }
 157                         else if (strcmp (value, "normal"))
 158                                 set_opt (*mount_options, CHECK_NORMAL);
 159                         else if (strcmp (value, "strict")) {
 160                                 set_opt (*mount_options, CHECK_NORMAL);
 161                                 set_opt (*mount_options, CHECK_STRICT);
 162                         }
 163                         else {
 164                                 printk ("EXT2-fs: Invalid check option: %s\n",
 165                                         value);
 166                                 return 0;
 167                         }
 168                 }
 169                 else if (!strcmp (this_char, "debug"))
 170                         set_opt (*mount_options, DEBUG);
 171                 else if (!strcmp (this_char, "errors")) {
 172                         if (!value || !*value) {
 173                                 printk ("EXT2-fs: the errors option requires "
 174                                         "an argument");
 175                                 return 0;
 176                         }
 177                         if (!strcmp (value, "continue")) {
 178                                 clear_opt (*mount_options, ERRORS_RO);
 179                                 clear_opt (*mount_options, ERRORS_PANIC);
 180                                 set_opt (*mount_options, ERRORS_CONT);
 181                         }
 182                         else if (!strcmp (value, "remount-ro")) {
 183                                 clear_opt (*mount_options, ERRORS_CONT);
 184                                 clear_opt (*mount_options, ERRORS_PANIC);
 185                                 set_opt (*mount_options, ERRORS_RO);
 186                         }
 187                         else if (!strcmp (value, "panic")) {
 188                                 clear_opt (*mount_options, ERRORS_CONT);
 189                                 clear_opt (*mount_options, ERRORS_RO);
 190                                 set_opt (*mount_options, ERRORS_PANIC);
 191                         }
 192                         else {
 193                                 printk ("EXT2-fs: Invalid errors option: %s\n",
 194                                         value);
 195                                 return 0;
 196                         }
 197                 }
 198                 else if (!strcmp (this_char, "grpid") ||
 199                          !strcmp (this_char, "bsdgroups"))
 200                         set_opt (*mount_options, GRPID);
 201                 else if (!strcmp (this_char, "minixdf"))
 202                         set_opt (*mount_options, MINIX_DF);
 203                 else if (!strcmp (this_char, "nocheck")) {
 204                         clear_opt (*mount_options, CHECK_NORMAL);
 205                         clear_opt (*mount_options, CHECK_STRICT);
 206                 }
 207                 else if (!strcmp (this_char, "nogrpid") ||
 208                          !strcmp (this_char, "sysvgroups"))
 209                         clear_opt (*mount_options, GRPID);
 210                 else if (!strcmp (this_char, "resgid")) {
 211                         if (!value || !*value) {
 212                                 printk ("EXT2-fs: the resgid option requires "
 213                                         "an argument");
 214                                 return 0;
 215                         }
 216                         *resgid = simple_strtoul (value, &value, 0);
 217                         if (*value) {
 218                                 printk ("EXT2-fs: Invalid resgid option: %s\n",
 219                                         value);
 220                                 return 0;
 221                         }
 222                 }
 223                 else if (!strcmp (this_char, "resuid")) {
 224                         if (!value || !*value) {
 225                                 printk ("EXT2-fs: the resuid option requires "
 226                                         "an argument");
 227                                 return 0;
 228                         }
 229                         *resuid = simple_strtoul (value, &value, 0);
 230                         if (*value) {
 231                                 printk ("EXT2-fs: Invalid resuid option: %s\n",
 232                                         value);
 233                                 return 0;
 234                         }
 235                 }
 236                 else if (!strcmp (this_char, "sb")) {
 237                         if (!value || !*value) {
 238                                 printk ("EXT2-fs: the sb option requires "
 239                                         "an argument");
 240                                 return 0;
 241                         }
 242                         *sb_block = simple_strtoul (value, &value, 0);
 243                         if (*value) {
 244                                 printk ("EXT2-fs: Invalid sb option: %s\n",
 245                                         value);
 246                                 return 0;
 247                         }
 248                 }
 249                 else {
 250                         printk ("EXT2-fs: Unrecognized mount option %s\n", this_char);
 251                         return 0;
 252                 }
 253         }
 254         return 1;
 255 }
 256 
 257 static void ext2_setup_super (struct super_block * sb,
     /* [previous][next][first][last][top][bottom][index][help] */
 258                               struct ext2_super_block * es)
 259 {
 260         if (es->s_rev_level > EXT2_CURRENT_REV) {
 261                         printk ("EXT2-fs warning: revision level too high, "
 262                                 "forcing read/only mode\n");
 263                         sb->s_flags |= MS_RDONLY;
 264         }
 265         if (!(sb->s_flags & MS_RDONLY)) {
 266                 if (!(sb->u.ext2_sb.s_mount_state & EXT2_VALID_FS))
 267                         printk ("EXT2-fs warning: mounting unchecked fs, "
 268                                 "running e2fsck is recommended\n");
 269                 else if ((sb->u.ext2_sb.s_mount_state & EXT2_ERROR_FS))
 270                         printk ("EXT2-fs warning: mounting fs with errors, "
 271                                 "running e2fsck is recommended\n");
 272                 else if (es->s_max_mnt_count >= 0 &&
 273                          es->s_mnt_count >= (unsigned short) es->s_max_mnt_count)
 274                         printk ("EXT2-fs warning: maximal mount count reached, "
 275                                 "running e2fsck is recommended\n");
 276                 else if (es->s_checkinterval &&
 277                         (es->s_lastcheck + es->s_checkinterval <= CURRENT_TIME))
 278                         printk ("EXT2-fs warning: checktime reached, "
 279                                 "running e2fsck is recommended\n");
 280                 es->s_state &= ~EXT2_VALID_FS;
 281                 if (!es->s_max_mnt_count)
 282                         es->s_max_mnt_count = EXT2_DFL_MAX_MNT_COUNT;
 283                 es->s_mnt_count++;
 284                 es->s_mtime = CURRENT_TIME;
 285                 mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
 286                 sb->s_dirt = 1;
 287                 if (test_opt (sb, DEBUG))
 288                         printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 289                                 "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 290                                 EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 291                                 sb->u.ext2_sb.s_frag_size,
 292                                 sb->u.ext2_sb.s_groups_count,
 293                                 EXT2_BLOCKS_PER_GROUP(sb),
 294                                 EXT2_INODES_PER_GROUP(sb),
 295                                 sb->u.ext2_sb.s_mount_opt);
 296                 if (test_opt (sb, CHECK)) {
 297                         ext2_check_blocks_bitmap (sb);
 298                         ext2_check_inodes_bitmap (sb);
 299                 }
 300         }
 301 }
 302 
 303 static int ext2_check_descriptors (struct super_block * sb)
     /* [previous][next][first][last][top][bottom][index][help] */
 304 {
 305         int i;
 306         int desc_block = 0;
 307         unsigned long block = sb->u.ext2_sb.s_es->s_first_data_block;
 308         struct ext2_group_desc * gdp = NULL;
 309 
 310         ext2_debug ("Checking group descriptors");
 311 
 312         for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++)
 313         {
 314                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 315                         gdp = (struct ext2_group_desc *) sb->u.ext2_sb.s_group_desc[desc_block++]->b_data;
 316                 if (gdp->bg_block_bitmap < block ||
 317                     gdp->bg_block_bitmap >= block + EXT2_BLOCKS_PER_GROUP(sb))
 318                 {
 319                         ext2_error (sb, "ext2_check_descriptors",
 320                                     "Block bitmap for group %d"
 321                                     " not in group (block %lu)!",
 322                                     i, (unsigned long) gdp->bg_block_bitmap);
 323                         return 0;
 324                 }
 325                 if (gdp->bg_inode_bitmap < block ||
 326                     gdp->bg_inode_bitmap >= block + EXT2_BLOCKS_PER_GROUP(sb))
 327                 {
 328                         ext2_error (sb, "ext2_check_descriptors",
 329                                     "Inode bitmap for group %d"
 330                                     " not in group (block %lu)!",
 331                                     i, (unsigned long) gdp->bg_inode_bitmap);
 332                         return 0;
 333                 }
 334                 if (gdp->bg_inode_table < block ||
 335                     gdp->bg_inode_table + sb->u.ext2_sb.s_itb_per_group >=
 336                     block + EXT2_BLOCKS_PER_GROUP(sb))
 337                 {
 338                         ext2_error (sb, "ext2_check_descriptors",
 339                                     "Inode table for group %d"
 340                                     " not in group (block %lu)!",
 341                                     i, (unsigned long) gdp->bg_inode_table);
 342                         return 0;
 343                 }
 344                 block += EXT2_BLOCKS_PER_GROUP(sb);
 345                 gdp++;
 346         }
 347         return 1;
 348 }
 349 
 350 #define log2(n) ffz(~(n))
 351 
 352 struct super_block * ext2_read_super (struct super_block * sb, void * data,
     /* [previous][next][first][last][top][bottom][index][help] */
 353                                       int silent)
 354 {
 355         struct buffer_head * bh;
 356         struct ext2_super_block * es;
 357         unsigned long sb_block = 1;
 358         unsigned short resuid = EXT2_DEF_RESUID;
 359         unsigned short resgid = EXT2_DEF_RESGID;
 360         unsigned long logic_sb_block = 1;
 361         int dev = sb->s_dev;
 362         int db_count;
 363         int i, j;
 364 
 365         set_opt (sb->u.ext2_sb.s_mount_opt, CHECK_NORMAL);
 366         if (!parse_options ((char *) data, &sb_block, &resuid, &resgid,
 367             &sb->u.ext2_sb.s_mount_opt)) {
 368                 sb->s_dev = 0;
 369                 return NULL;
 370         }
 371 
 372         lock_super (sb);
 373         set_blocksize (dev, BLOCK_SIZE);
 374         if (!(bh = bread (dev, sb_block, BLOCK_SIZE))) {
 375                 sb->s_dev = 0;
 376                 unlock_super (sb);
 377                 printk ("EXT2-fs: unable to read superblock\n");
 378                 return NULL;
 379         }
 380         /*
 381          * Note: s_es must be initialized s_es as soon as possible because
 382          * some ext2 macro-instructions depend on its value
 383          */
 384         es = (struct ext2_super_block *) bh->b_data;
 385         sb->u.ext2_sb.s_es = es;
 386         sb->s_magic = es->s_magic;
 387         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 388                 sb->s_dev = 0;
 389                 unlock_super (sb);
 390                 brelse (bh);
 391                 if (!silent)
 392                         printk ("VFS: Can't find an ext2 filesystem on dev %d/%d.\n",
 393                                 MAJOR(dev), MINOR(dev));
 394                 return NULL;
 395         }
 396         sb->s_blocksize_bits = sb->u.ext2_sb.s_es->s_log_block_size + 10;
 397         sb->s_blocksize = 1 << sb->s_blocksize_bits;
 398         if (sb->s_blocksize != BLOCK_SIZE && 
 399             (sb->s_blocksize == 1024 || sb->s_blocksize == 2048 ||  
 400              sb->s_blocksize == 4096)) {
 401                 unsigned long offset;
 402 
 403                 brelse (bh);
 404                 set_blocksize (dev, sb->s_blocksize);
 405                 logic_sb_block = (sb_block*BLOCK_SIZE) / sb->s_blocksize;
 406                 offset = (sb_block*BLOCK_SIZE) % sb->s_blocksize;
 407                 bh = bread (dev, logic_sb_block, sb->s_blocksize);
 408                 if(!bh)
 409                         return NULL;
 410                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 411                 sb->u.ext2_sb.s_es = es;
 412                 if (es->s_magic != EXT2_SUPER_MAGIC) {
 413                         sb->s_dev = 0;
 414                         unlock_super (sb);
 415                         brelse (bh);
 416                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 417                         return NULL;
 418                 }
 419         }
 420         sb->u.ext2_sb.s_frag_size = EXT2_MIN_FRAG_SIZE <<
 421                                    es->s_log_frag_size;
 422         if (sb->u.ext2_sb.s_frag_size)
 423                 sb->u.ext2_sb.s_frags_per_block = sb->s_blocksize /
 424                                                   sb->u.ext2_sb.s_frag_size;
 425         else
 426                 sb->s_magic = 0;
 427         sb->u.ext2_sb.s_blocks_per_group = es->s_blocks_per_group;
 428         sb->u.ext2_sb.s_frags_per_group = es->s_frags_per_group;
 429         sb->u.ext2_sb.s_inodes_per_group = es->s_inodes_per_group;
 430         sb->u.ext2_sb.s_inodes_per_block = sb->s_blocksize /
 431                                            sizeof (struct ext2_inode);
 432         sb->u.ext2_sb.s_itb_per_group = sb->u.ext2_sb.s_inodes_per_group /
 433                                         sb->u.ext2_sb.s_inodes_per_block;
 434         sb->u.ext2_sb.s_desc_per_block = sb->s_blocksize /
 435                                          sizeof (struct ext2_group_desc);
 436         sb->u.ext2_sb.s_sbh = bh;
 437         if (resuid != EXT2_DEF_RESUID)
 438                 sb->u.ext2_sb.s_resuid = resuid;
 439         else
 440                 sb->u.ext2_sb.s_resuid = es->s_def_resuid;
 441         if (resgid != EXT2_DEF_RESGID)
 442                 sb->u.ext2_sb.s_resgid = resgid;
 443         else
 444                 sb->u.ext2_sb.s_resgid = es->s_def_resgid;
 445         sb->u.ext2_sb.s_mount_state = es->s_state;
 446         sb->u.ext2_sb.s_rename_lock = 0;
 447         sb->u.ext2_sb.s_rename_wait = NULL;
 448         sb->u.ext2_sb.s_addr_per_block_bits =
 449                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 450         sb->u.ext2_sb.s_inodes_per_block_bits =
 451                 log2 (EXT2_INODES_PER_BLOCK(sb));
 452         sb->u.ext2_sb.s_desc_per_block_bits =
 453                 log2 (EXT2_DESC_PER_BLOCK(sb));
 454         if (sb->s_magic != EXT2_SUPER_MAGIC) {
 455                 sb->s_dev = 0;
 456                 unlock_super (sb);
 457                 brelse (bh);
 458                 if (!silent)
 459                         printk ("VFS: Can't find an ext2 filesystem on dev %d/%d.\n",
 460                                 MAJOR(dev), MINOR(dev));
 461                 return NULL;
 462         }
 463         if (sb->s_blocksize != bh->b_size) {
 464                 sb->s_dev = 0;
 465                 unlock_super (sb);
 466                 brelse (bh);
 467                 if (!silent)
 468                         printk ("VFS: Unsupported blocksize on dev 0x%04x.\n",
 469                                 dev);
 470                 return NULL;
 471         }
 472 
 473         if (sb->s_blocksize != sb->u.ext2_sb.s_frag_size) {
 474                 sb->s_dev = 0;
 475                 unlock_super (sb);
 476                 brelse (bh);
 477                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 478                         sb->u.ext2_sb.s_frag_size, sb->s_blocksize);
 479                 return NULL;
 480         }
 481 
 482         if (sb->u.ext2_sb.s_blocks_per_group > sb->s_blocksize * 8) {
 483                 sb->s_dev = 0;
 484                 unlock_super (sb);
 485                 brelse (bh);
 486                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 487                         sb->u.ext2_sb.s_blocks_per_group);
 488                 return NULL;
 489         }
 490         if (sb->u.ext2_sb.s_frags_per_group > sb->s_blocksize * 8) {
 491                 sb->s_dev = 0;
 492                 unlock_super (sb);
 493                 brelse (bh);
 494                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 495                         sb->u.ext2_sb.s_frags_per_group);
 496                 return NULL;
 497         }
 498         if (sb->u.ext2_sb.s_inodes_per_group > sb->s_blocksize * 8) {
 499                 sb->s_dev = 0;
 500                 unlock_super (sb);
 501                 brelse (bh);
 502                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 503                         sb->u.ext2_sb.s_inodes_per_group);
 504                 return NULL;
 505         }
 506 
 507         sb->u.ext2_sb.s_groups_count = (es->s_blocks_count -
 508                                         es->s_first_data_block +
 509                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 510                                        EXT2_BLOCKS_PER_GROUP(sb);
 511         db_count = (sb->u.ext2_sb.s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 512                    EXT2_DESC_PER_BLOCK(sb);
 513         sb->u.ext2_sb.s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 514         if (sb->u.ext2_sb.s_group_desc == NULL) {
 515                 sb->s_dev = 0;
 516                 unlock_super (sb);
 517                 brelse (bh);
 518                 printk ("EXT2-fs: not enough memory\n");
 519                 return NULL;
 520         }
 521         for (i = 0; i < db_count; i++) {
 522                 sb->u.ext2_sb.s_group_desc[i] = bread (dev, logic_sb_block + i + 1,
 523                                                        sb->s_blocksize);
 524                 if (!sb->u.ext2_sb.s_group_desc[i]) {
 525                         sb->s_dev = 0;
 526                         unlock_super (sb);
 527                         for (j = 0; j < i; j++)
 528                                 brelse (sb->u.ext2_sb.s_group_desc[j]);
 529                         kfree_s (sb->u.ext2_sb.s_group_desc,
 530                                  db_count * sizeof (struct buffer_head *));
 531                         brelse (bh);
 532                         printk ("EXT2-fs: unable to read group descriptors\n");
 533                         return NULL;
 534                 }
 535         }
 536         if (!ext2_check_descriptors (sb)) {
 537                 sb->s_dev = 0;
 538                 unlock_super (sb);
 539                 for (j = 0; j < db_count; j++)
 540                         brelse (sb->u.ext2_sb.s_group_desc[j]);
 541                 kfree_s (sb->u.ext2_sb.s_group_desc,
 542                          db_count * sizeof (struct buffer_head *));
 543                 brelse (bh);
 544                 printk ("EXT2-fs: group descriptors corrupted !\n");
 545                 return NULL;
 546         }
 547         for (i = 0; i < EXT2_MAX_GROUP_LOADED; i++) {
 548                 sb->u.ext2_sb.s_inode_bitmap_number[i] = 0;
 549                 sb->u.ext2_sb.s_inode_bitmap[i] = NULL;
 550                 sb->u.ext2_sb.s_block_bitmap_number[i] = 0;
 551                 sb->u.ext2_sb.s_block_bitmap[i] = NULL;
 552         }
 553         sb->u.ext2_sb.s_loaded_inode_bitmaps = 0;
 554         sb->u.ext2_sb.s_loaded_block_bitmaps = 0;
 555         sb->u.ext2_sb.s_db_per_group = db_count;
 556         unlock_super (sb);
 557         /*
 558          * set up enough so that it can read an inode
 559          */
 560         sb->s_dev = dev;
 561         sb->s_op = &ext2_sops;
 562         if (!(sb->s_mounted = iget (sb, EXT2_ROOT_INO))) {
 563                 sb->s_dev = 0;
 564                 for (i = 0; i < db_count; i++)
 565                         if (sb->u.ext2_sb.s_group_desc[i])
 566                                 brelse (sb->u.ext2_sb.s_group_desc[i]);
 567                 kfree_s (sb->u.ext2_sb.s_group_desc,
 568                          db_count * sizeof (struct buffer_head *));
 569                 brelse (bh);
 570                 printk ("EXT2-fs: get root inode failed\n");
 571                 return NULL;
 572         }
 573         ext2_setup_super (sb, es);
 574         return sb;
 575 }
 576 
 577 static void ext2_commit_super (struct super_block * sb,
     /* [previous][next][first][last][top][bottom][index][help] */
 578                                struct ext2_super_block * es)
 579 {
 580         es->s_wtime = CURRENT_TIME;
 581         mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
 582         sb->s_dirt = 0;
 583 }
 584 
 585 /*
 586  * In the second extended file system, it is not necessary to
 587  * write the super block since we use a mapping of the
 588  * disk super block in a buffer.
 589  *
 590  * However, this function is still used to set the fs valid
 591  * flags to 0.  We need to set this flag to 0 since the fs
 592  * may have been checked while mounted and e2fsck may have
 593  * set s_state to EXT2_VALID_FS after some corrections.
 594  */
 595 
 596 void ext2_write_super (struct super_block * sb)
     /* [previous][next][first][last][top][bottom][index][help] */
 597 {
 598         struct ext2_super_block * es;
 599 
 600         if (!(sb->s_flags & MS_RDONLY)) {
 601                 es = sb->u.ext2_sb.s_es;
 602 
 603                 ext2_debug ("setting valid to 0\n");
 604 
 605                 if (es->s_state & EXT2_VALID_FS) {
 606                         es->s_state &= ~EXT2_VALID_FS;
 607                         es->s_mtime = CURRENT_TIME;
 608                 }
 609                 ext2_commit_super (sb, es);
 610         }
 611         sb->s_dirt = 0;
 612 }
 613 
 614 int ext2_remount (struct super_block * sb, int * flags, char * data)
     /* [previous][next][first][last][top][bottom][index][help] */
 615 {
 616         struct ext2_super_block * es;
 617         unsigned short resuid = sb->u.ext2_sb.s_resuid;
 618         unsigned short resgid = sb->u.ext2_sb.s_resgid;
 619         unsigned long new_mount_opt;
 620         unsigned long tmp;
 621 
 622         /*
 623          * Allow the "check" option to be passed as a remount option.
 624          */
 625         set_opt (sb->u.ext2_sb.s_mount_opt, CHECK_NORMAL);
 626         if (!parse_options (data, &tmp, &resuid, &resgid,
 627                             &new_mount_opt))
 628                 return -EINVAL;
 629 
 630         sb->u.ext2_sb.s_mount_opt = new_mount_opt;
 631         sb->u.ext2_sb.s_resuid = resuid;
 632         sb->u.ext2_sb.s_resgid = resgid;
 633         es = sb->u.ext2_sb.s_es;
 634         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 635                 return 0;
 636         if (*flags & MS_RDONLY) {
 637                 if (es->s_state & EXT2_VALID_FS ||
 638                     !(sb->u.ext2_sb.s_mount_state & EXT2_VALID_FS))
 639                         return 0;
 640                 /*
 641                  * OK, we are remounting a valid rw partition rdonly, so set
 642                  * the rdonly flag and then mark the partition as valid again.
 643                  */
 644                 es->s_state = sb->u.ext2_sb.s_mount_state;
 645                 es->s_mtime = CURRENT_TIME;
 646                 mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
 647                 sb->s_dirt = 1;
 648                 ext2_commit_super (sb, es);
 649         }
 650         else {
 651                 /*
 652                  * Mounting a RDONLY partition read-write, so reread and
 653                  * store the current valid flag.  (It may have been changed 
 654                  * by e2fsck since we originally mounted the partition.)
 655                  */
 656                 sb->u.ext2_sb.s_mount_state = es->s_state;
 657                 sb->s_flags &= ~MS_RDONLY;
 658                 ext2_setup_super (sb, es);
 659         }
 660         return 0;
 661 }
 662 
 663 void ext2_statfs (struct super_block * sb, struct statfs * buf, int bufsiz)
     /* [previous][next][first][last][top][bottom][index][help] */
 664 {
 665         unsigned long overhead;
 666         unsigned long overhead_per_group;
 667         struct statfs tmp;
 668 
 669         if (test_opt (sb, MINIX_DF))
 670                 overhead = 0;
 671         else {
 672                 /*
 673                  * Compute the overhead (FS structures)
 674                  */
 675                 overhead_per_group = 1 /* super block */ +
 676                                      sb->u.ext2_sb.s_db_per_group /* descriptors */ +
 677                                      1 /* block bitmap */ +
 678                                      1 /* inode bitmap */ +
 679                                      sb->u.ext2_sb.s_itb_per_group /* inode table */;
 680                 overhead = sb->u.ext2_sb.s_es->s_first_data_block +
 681                            sb->u.ext2_sb.s_groups_count * overhead_per_group;
 682         }
 683 
 684         tmp.f_type = EXT2_SUPER_MAGIC;
 685         tmp.f_bsize = sb->s_blocksize;
 686         tmp.f_blocks = sb->u.ext2_sb.s_es->s_blocks_count - overhead;
 687         tmp.f_bfree = ext2_count_free_blocks (sb);
 688         tmp.f_bavail = tmp.f_bfree - sb->u.ext2_sb.s_es->s_r_blocks_count;
 689         if (tmp.f_bfree < sb->u.ext2_sb.s_es->s_r_blocks_count)
 690                 tmp.f_bavail = 0;
 691         tmp.f_files = sb->u.ext2_sb.s_es->s_inodes_count;
 692         tmp.f_ffree = ext2_count_free_inodes (sb);
 693         tmp.f_namelen = EXT2_NAME_LEN;
 694         memcpy_tofs(buf, &tmp, bufsiz);
 695 }

/* [previous][next][first][last][top][bottom][index][help] */