lib/ext2fs/initialize.c

   1 /*
   2  * initialize.c --- initialize a filesystem handle given superblock
   3  *      parameters.  Used by mke2fs when initializing a filesystem.
   4  *
   5  * Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Library
   9  * General Public License, version 2.
  10  * %End-Header%
  11  */
  12
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #include <fcntl.h>
  19 #include <time.h>
  20 #if HAVE_SYS_STAT_H
  21 #include <sys/stat.h>
  22 #endif
  23 #if HAVE_SYS_TYPES_H
  24 #include <sys/types.h>
  25 #endif
  26
  27 #include "ext2_fs.h"
  28 #include "ext2fs.h"
  29
  30 #if defined(__linux__)    &&    defined(EXT2_OS_LINUX)
  31 #define CREATOR_OS EXT2_OS_LINUX
  32 #else
  33 #if defined(__GNU__)     &&     defined(EXT2_OS_HURD)
  34 #define CREATOR_OS EXT2_OS_HURD
  35 #else
  36 #if defined(__FreeBSD__) &&     defined(EXT2_OS_FREEBSD)
  37 #define CREATOR_OS EXT2_OS_FREEBSD
  38 #else
  39 #if defined(LITES)         &&   defined(EXT2_OS_LITES)
  40 #define CREATOR_OS EXT2_OS_LITES
  41 #else
  42 #define CREATOR_OS EXT2_OS_LINUX /* by default */
  43 #endif /* defined(LITES) && defined(EXT2_OS_LITES) */
  44 #endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
  45 #endif /* defined(__GNU__)     && defined(EXT2_OS_HURD) */
  46 #endif /* defined(__linux__)   && defined(EXT2_OS_LINUX) */
  47
  48 /*
  49  * Calculate the number of GDT blocks to reserve for online filesystem growth.
  50  * The absolute maximum number of GDT blocks we can reserve is determined by
  51  * the number of block pointers that can fit into a single block.
  52  */
  53 static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs)
  54 {
  55         struct ext2_super_block *sb = fs->super;
  56         unsigned long bpg = sb->s_blocks_per_group;
  57         unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb);
  58         unsigned long max_blocks = 0xffffffff;
  59         unsigned long rsv_groups;
  60         unsigned int rsv_gdb;
  61
  62         /* We set it at 1024x the current filesystem size, or
  63          * the upper block count limit (2^32), whichever is lower.
  64          */
  65         if (ext2fs_blocks_count(sb) < max_blocks / 1024)
  66                 max_blocks = ext2fs_blocks_count(sb) * 1024;
  67         /*
  68          * ext2fs_div64_ceil() is unnecessary because max_blocks is
  69          * max _GDT_ blocks, which is limited to 32 bits.
  70          */
  71         rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
  72         rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks;
  73         if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
  74                 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
  75 #ifdef RES_GDT_DEBUG
  76         printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n",
  77                max_blocks, rsv_groups, rsv_gdb);
  78 #endif
  79
  80         return rsv_gdb;
  81 }
  82
  83 errcode_t ext2fs_initialize(const char *name, int flags,
  84                             struct ext2_super_block *param,
  85                             io_manager manager, ext2_filsys *ret_fs)
  86 {
  87         ext2_filsys     fs;
  88         errcode_t       retval;
  89         struct ext2_super_block *super;
  90         unsigned int    rem;
  91         unsigned int    overhead = 0;
  92         unsigned int    ipg;
  93         dgrp_t          i;
  94         blk64_t         free_blocks;
  95         blk_t           numblocks;
  96         int             rsv_gdt;
  97         int             csum_flag;
  98         int             bigalloc_flag;
  99         int             io_flags;
 100         char            *buf = 0;
 101         char            c;
 102
 103         if (!param || !ext2fs_blocks_count(param))
 104                 return EXT2_ET_INVALID_ARGUMENT;
 105
 106         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 107         if (retval)
 108                 return retval;
 109
 110         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 111         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 112         fs->flags = flags | EXT2_FLAG_RW;
 113         fs->umask = 022;
 114 #ifdef WORDS_BIGENDIAN
 115         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 116 #endif
 117         io_flags = IO_FLAG_RW;
 118         if (flags & EXT2_FLAG_EXCLUSIVE)
 119                 io_flags |= IO_FLAG_EXCLUSIVE;
 120         retval = manager->open(name, io_flags, &fs->io);
 121         if (retval)
 122                 goto cleanup;
 123         fs->image_io = fs->io;
 124         fs->io->app_data = fs;
 125         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 126         if (retval)
 127                 goto cleanup;
 128
 129         strcpy(fs->device_name, name);
 130         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 131         if (retval)
 132                 goto cleanup;
 133         fs->super = super;
 134
 135         memset(super, 0, SUPERBLOCK_SIZE);
 136
 137 #define set_field(field, default) (super->field = param->field ? \
 138                                    param->field : (default))
 139 #define assign_field(field)     (super->field = param->field)
 140
 141         super->s_magic = EXT2_SUPER_MAGIC;
 142         super->s_state = EXT2_VALID_FS;
 143
 144         bigalloc_flag = EXT2_HAS_RO_COMPAT_FEATURE(param,
 145                                    EXT4_FEATURE_RO_COMPAT_BIGALLOC);
 146
 147         assign_field(s_log_block_size);
 148
 149         if (bigalloc_flag) {
 150                 set_field(s_log_cluster_size, super->s_log_block_size+4);
 151                 if (super->s_log_block_size > super->s_log_cluster_size) {
 152                         retval = EXT2_ET_INVALID_ARGUMENT;
 153                         goto cleanup;
 154                 }
 155         } else
 156                 super->s_log_cluster_size = super->s_log_block_size;
 157
 158         set_field(s_first_data_block, super->s_log_cluster_size ? 0 : 1);
 159         set_field(s_max_mnt_count, 0);
 160         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 161         set_field(s_feature_compat, 0);
 162         set_field(s_feature_incompat, 0);
 163         set_field(s_feature_ro_compat, 0);
 164         set_field(s_default_mount_opts, 0);
 165         set_field(s_first_meta_bg, 0);
 166         set_field(s_raid_stride, 0);            /* default stride size: 0 */
 167         set_field(s_raid_stripe_width, 0);      /* default stripe width: 0 */
 168         set_field(s_log_groups_per_flex, 0);
 169         set_field(s_flags, 0);
 170         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 171                 retval = EXT2_ET_UNSUPP_FEATURE;
 172                 goto cleanup;
 173         }
 174         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
 175                 retval = EXT2_ET_RO_UNSUPP_FEATURE;
 176                 goto cleanup;
 177         }
 178
 179         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 180         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 181                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 182                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 183                 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
 184                         int extra_isize = sizeof(struct ext2_inode_large) -
 185                                 EXT2_GOOD_OLD_INODE_SIZE;
 186                         set_field(s_min_extra_isize, extra_isize);
 187                         set_field(s_want_extra_isize, extra_isize);
 188                 }
 189         } else {
 190                 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 191                 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 192         }
 193
 194         set_field(s_checkinterval, 0);
 195         super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
 196
 197         super->s_creator_os = CREATOR_OS;
 198
 199         fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(super);
 200         fs->cluster_ratio_bits = super->s_log_cluster_size -
 201                 super->s_log_block_size;
 202
 203         if (bigalloc_flag) {
 204                 if (param->s_blocks_per_group &&
 205                     param->s_clusters_per_group &&
 206                     ((param->s_clusters_per_group * EXT2FS_CLUSTER_RATIO(fs)) !=
 207                      param->s_blocks_per_group)) {
 208                         retval = EXT2_ET_INVALID_ARGUMENT;
 209                         goto cleanup;
 210                 }
 211                 if (param->s_clusters_per_group)
 212                         assign_field(s_clusters_per_group);
 213                 else if (param->s_blocks_per_group)
 214                         super->s_clusters_per_group =
 215                                 param->s_blocks_per_group /
 216                                 EXT2FS_CLUSTER_RATIO(fs);
 217                 else
 218                         super->s_clusters_per_group = fs->blocksize * 8;
 219                 if (super->s_clusters_per_group > EXT2_MAX_CLUSTERS_PER_GROUP(super))
 220                         super->s_blocks_per_group = EXT2_MAX_CLUSTERS_PER_GROUP(super);
 221                 super->s_blocks_per_group = EXT2FS_C2B(fs,
 222                                        super->s_clusters_per_group);
 223         } else {
 224                 set_field(s_blocks_per_group, fs->blocksize * 8);
 225                 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 226                         super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 227                 super->s_clusters_per_group = super->s_blocks_per_group;
 228         }
 229
 230         ext2fs_blocks_count_set(super, ext2fs_blocks_count(param) &
 231                                 ~((blk64_t) EXT2FS_CLUSTER_MASK(fs)));
 232         ext2fs_r_blocks_count_set(super, ext2fs_r_blocks_count(param));
 233         if (ext2fs_r_blocks_count(super) >= ext2fs_blocks_count(param)) {
 234                 retval = EXT2_ET_INVALID_ARGUMENT;
 235                 goto cleanup;
 236         }
 237
 238         /*
 239          * If we're creating an external journal device, we don't need
 240          * to bother with the rest.
 241          */
 242         if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 243                 fs->group_desc_count = 0;
 244                 ext2fs_mark_super_dirty(fs);
 245                 *ret_fs = fs;
 246                 return 0;
 247         }
 248
 249 retry:
 250         fs->group_desc_count = (blk_t) ext2fs_div64_ceil(
 251                 ext2fs_blocks_count(super) - super->s_first_data_block,
 252                 EXT2_BLOCKS_PER_GROUP(super));
 253         if (fs->group_desc_count == 0) {
 254                 retval = EXT2_ET_TOOSMALL;
 255                 goto cleanup;
 256         }
 257
 258         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT)
 259                 super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT;
 260
 261         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 262                                           EXT2_DESC_PER_BLOCK(super));
 263
 264         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 265
 266         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT &&
 267             (ext2fs_blocks_count(super) / i) > (1ULL << 32))
 268                 set_field(s_inodes_count, ~0U);
 269         else
 270                 set_field(s_inodes_count, ext2fs_blocks_count(super) / i);
 271
 272         /*
 273          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 274          * that we have enough inodes for the filesystem(!)
 275          */
 276         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 277                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 278
 279         /*
 280          * There should be at least as many inodes as the user
 281          * requested.  Figure out how many inodes per group that
 282          * should be.  But make sure that we don't allocate more than
 283          * one bitmap's worth of inodes each group.
 284          */
 285         ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
 286         if (ipg > fs->blocksize * 8) {
 287                 if (!bigalloc_flag && super->s_blocks_per_group >= 256) {
 288                         /* Try again with slightly different parameters */
 289                         super->s_blocks_per_group -= 8;
 290                         ext2fs_blocks_count_set(super,
 291                                                 ext2fs_blocks_count(param));
 292                         super->s_clusters_per_group = super->s_blocks_per_group;
 293                         goto retry;
 294                 } else {
 295                         retval = EXT2_ET_TOO_MANY_INODES;
 296                         goto cleanup;
 297                 }
 298         }
 299
 300         if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
 301                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 302
 303 ipg_retry:
 304         super->s_inodes_per_group = ipg;
 305
 306         /*
 307          * Make sure the number of inodes per group completely fills
 308          * the inode table blocks in the descriptor.  If not, add some
 309          * additional inodes/group.  Waste not, want not...
 310          */
 311         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 312                                         EXT2_INODE_SIZE(super)) +
 313                                        EXT2_BLOCK_SIZE(super) - 1) /
 314                                       EXT2_BLOCK_SIZE(super));
 315         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 316                                       EXT2_BLOCK_SIZE(super)) /
 317                                      EXT2_INODE_SIZE(super));
 318         /*
 319          * Finally, make sure the number of inodes per group is a
 320          * multiple of 8.  This is needed to simplify the bitmap
 321          * splicing code.
 322          */
 323         if (super->s_inodes_per_group < 8)
 324                 super->s_inodes_per_group = 8;
 325         super->s_inodes_per_group &= ~7;
 326         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 327                                         EXT2_INODE_SIZE(super)) +
 328                                        EXT2_BLOCK_SIZE(super) - 1) /
 329                                       EXT2_BLOCK_SIZE(super));
 330
 331         /*
 332          * adjust inode count to reflect the adjusted inodes_per_group
 333          */
 334         if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
 335                 ipg--;
 336                 goto ipg_retry;
 337         }
 338         super->s_inodes_count = super->s_inodes_per_group *
 339                 fs->group_desc_count;
 340         super->s_free_inodes_count = super->s_inodes_count;
 341
 342         /*
 343          * check the number of reserved group descriptor table blocks
 344          */
 345         if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
 346                 rsv_gdt = calc_reserved_gdt_blocks(fs);
 347         else
 348                 rsv_gdt = 0;
 349         set_field(s_reserved_gdt_blocks, rsv_gdt);
 350         if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
 351                 retval = EXT2_ET_RES_GDT_BLOCKS;
 352                 goto cleanup;
 353         }
 354
 355         /*
 356          * Calculate the maximum number of bookkeeping blocks per
 357          * group.  It includes the superblock, the block group
 358          * descriptors, the block bitmap, the inode bitmap, the inode
 359          * table, and the reserved gdt blocks.
 360          */
 361         overhead = (int) (3 + fs->inode_blocks_per_group +
 362                           fs->desc_blocks + super->s_reserved_gdt_blocks);
 363
 364         /* This can only happen if the user requested too many inodes */
 365         if (overhead > super->s_blocks_per_group) {
 366                 retval = EXT2_ET_TOO_MANY_INODES;
 367                 goto cleanup;
 368         }
 369
 370         /*
 371          * See if the last group is big enough to support the
 372          * necessary data structures.  If not, we need to get rid of
 373          * it.  We need to recalculate the overhead for the last block
 374          * group, since it might or might not have a superblock
 375          * backup.
 376          */
 377         overhead = (int) (2 + fs->inode_blocks_per_group);
 378         if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
 379                 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
 380         rem = ((ext2fs_blocks_count(super) - super->s_first_data_block) %
 381                super->s_blocks_per_group);
 382         if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
 383                 retval = EXT2_ET_TOOSMALL;
 384                 goto cleanup;
 385         }
 386         if (rem && (rem < overhead+50)) {
 387                 ext2fs_blocks_count_set(super, ext2fs_blocks_count(super) -
 388                                         rem);
 389
 390                 goto retry;
 391         }
 392
 393         /*
 394          * At this point we know how big the filesystem will be.  So
 395          * we can do any and all allocations that depend on the block
 396          * count.
 397          */
 398
 399         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 400         if (retval)
 401                 goto cleanup;
 402
 403         strcpy(buf, "block bitmap for ");
 404         strcat(buf, fs->device_name);
 405         retval = ext2fs_allocate_subcluster_bitmap(fs, buf, &fs->block_map);
 406         if (retval)
 407                 goto cleanup;
 408
 409         strcpy(buf, "inode bitmap for ");
 410         strcat(buf, fs->device_name);
 411         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 412         if (retval)
 413                 goto cleanup;
 414
 415         ext2fs_free_mem(&buf);
 416
 417         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 418                                 &fs->group_desc);
 419         if (retval)
 420                 goto cleanup;
 421
 422         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 423
 424         /*
 425          * Reserve the superblock and group descriptors for each
 426          * group, and fill in the correct group statistics for group.
 427          * Note that although the block bitmap, inode bitmap, and
 428          * inode table have not been allocated (and in fact won't be
 429          * by this routine), they are accounted for nevertheless.
 430          *
 431          * If FLEX_BG meta-data grouping is used, only account for the
 432          * superblock and group descriptors (the inode tables and
 433          * bitmaps will be accounted for when allocated).
 434          */
 435         free_blocks = 0;
 436         csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 437                                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
 438         for (i = 0; i < fs->group_desc_count; i++) {
 439                 /*
 440                  * Don't set the BLOCK_UNINIT group for the last group
 441                  * because the block bitmap needs to be padded.
 442                  */
 443                 if (csum_flag) {
 444                         if (i != fs->group_desc_count - 1)
 445                                 ext2fs_bg_flags_set(fs, i,
 446                                                     EXT2_BG_BLOCK_UNINIT);
 447                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 448                         numblocks = super->s_inodes_per_group;
 449                         if (i == 0)
 450                                 numblocks -= super->s_first_ino;
 451                         ext2fs_bg_itable_unused_set(fs, i, numblocks);
 452                 }
 453                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 454                 if (fs->super->s_log_groups_per_flex)
 455                         numblocks += 2 + fs->inode_blocks_per_group;
 456
 457                 free_blocks += numblocks;
 458                 ext2fs_bg_free_blocks_count_set(fs, i, numblocks);
 459                 ext2fs_bg_free_inodes_count_set(fs, i, fs->super->s_inodes_per_group);
 460                 ext2fs_bg_used_dirs_count_set(fs, i, 0);
 461                 ext2fs_group_desc_csum_set(fs, i);
 462         }
 463         free_blocks &= ~EXT2FS_CLUSTER_MASK(fs);
 464         ext2fs_free_blocks_count_set(super, free_blocks);
 465
 466         c = (char) 255;
 467         if (((int) c) == -1) {
 468                 super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
 469         } else {
 470                 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
 471         }
 472
 473         ext2fs_mark_super_dirty(fs);
 474         ext2fs_mark_bb_dirty(fs);
 475         ext2fs_mark_ib_dirty(fs);
 476
 477         io_channel_set_blksize(fs->io, fs->blocksize);
 478
 479         *ret_fs = fs;
 480         return 0;
 481 cleanup:
 482         free(buf);
 483         ext2fs_free(fs);
 484         return retval;
 485 }