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         int             frags_per_block;
  91         unsigned int    rem;
  92         unsigned int    overhead = 0;
  93         unsigned int    ipg;
  94         dgrp_t          i;
  95         blk_t           numblocks;
  96         int             rsv_gdt;
  97         int             csum_flag;
  98         int             io_flags;
  99         char            *buf = 0;
 100         char            c;
 101
 102         if (!param || !ext2fs_blocks_count(param))
 103                 return EXT2_ET_INVALID_ARGUMENT;
 104
 105         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 106         if (retval)
 107                 return retval;
 108
 109         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 110         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 111         fs->flags = flags | EXT2_FLAG_RW;
 112         fs->umask = 022;
 113 #ifdef WORDS_BIGENDIAN
 114         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 115 #endif
 116         io_flags = IO_FLAG_RW;
 117         if (flags & EXT2_FLAG_EXCLUSIVE)
 118                 io_flags |= IO_FLAG_EXCLUSIVE;
 119         retval = manager->open(name, io_flags, &fs->io);
 120         if (retval)
 121                 goto cleanup;
 122         fs->image_io = fs->io;
 123         fs->io->app_data = fs;
 124         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 125         if (retval)
 126                 goto cleanup;
 127
 128         strcpy(fs->device_name, name);
 129         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 130         if (retval)
 131                 goto cleanup;
 132         fs->super = super;
 133
 134         memset(super, 0, SUPERBLOCK_SIZE);
 135
 136 #define set_field(field, default) (super->field = param->field ? \
 137                                    param->field : (default))
 138
 139         super->s_magic = EXT2_SUPER_MAGIC;
 140         super->s_state = EXT2_VALID_FS;
 141
 142         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 143         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 144         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 145         set_field(s_max_mnt_count, 0);
 146         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 147         set_field(s_feature_compat, 0);
 148         set_field(s_feature_incompat, 0);
 149         set_field(s_feature_ro_compat, 0);
 150         set_field(s_default_mount_opts, 0);
 151         set_field(s_first_meta_bg, 0);
 152         set_field(s_raid_stride, 0);            /* default stride size: 0 */
 153         set_field(s_raid_stripe_width, 0);      /* default stripe width: 0 */
 154         set_field(s_log_groups_per_flex, 0);
 155         set_field(s_flags, 0);
 156         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 157                 retval = EXT2_ET_UNSUPP_FEATURE;
 158                 goto cleanup;
 159         }
 160         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
 161                 retval = EXT2_ET_RO_UNSUPP_FEATURE;
 162                 goto cleanup;
 163         }
 164
 165         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 166         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 167                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 168                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 169                 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
 170                         int extra_isize = sizeof(struct ext2_inode_large) -
 171                                 EXT2_GOOD_OLD_INODE_SIZE;
 172                         set_field(s_min_extra_isize, extra_isize);
 173                         set_field(s_want_extra_isize, extra_isize);
 174                 }
 175         } else {
 176                 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 177                 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 178         }
 179
 180         set_field(s_checkinterval, 0);
 181         super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
 182
 183         super->s_creator_os = CREATOR_OS;
 184
 185         fs->blocksize = EXT2_BLOCK_SIZE(super);
 186         fs->fragsize = EXT2_FRAG_SIZE(super);
 187         frags_per_block = fs->blocksize / fs->fragsize;
 188
 189         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 190         set_field(s_blocks_per_group, fs->blocksize * 8);
 191         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 192                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 193         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 194
 195         ext2fs_blocks_count_set(super, ext2fs_blocks_count(param));
 196         ext2fs_r_blocks_count_set(super, ext2fs_r_blocks_count(param));
 197         if (ext2fs_r_blocks_count(super) >= ext2fs_blocks_count(param)) {
 198                 retval = EXT2_ET_INVALID_ARGUMENT;
 199                 goto cleanup;
 200         }
 201
 202         /*
 203          * If we're creating an external journal device, we don't need
 204          * to bother with the rest.
 205          */
 206         if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 207                 fs->group_desc_count = 0;
 208                 ext2fs_mark_super_dirty(fs);
 209                 *ret_fs = fs;
 210                 return 0;
 211         }
 212
 213 retry:
 214         fs->group_desc_count = (blk_t) ext2fs_div64_ceil(
 215                 ext2fs_blocks_count(super) - super->s_first_data_block,
 216                 EXT2_BLOCKS_PER_GROUP(super));
 217         if (fs->group_desc_count == 0) {
 218                 retval = EXT2_ET_TOOSMALL;
 219                 goto cleanup;
 220         }
 221
 222         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT)
 223                 super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT;
 224
 225         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 226                                           EXT2_DESC_PER_BLOCK(super));
 227
 228         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 229
 230         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT &&
 231             (ext2fs_blocks_count(super) / i) > (1ULL << 32))
 232                 set_field(s_inodes_count, ~0U);
 233         else
 234                 set_field(s_inodes_count, ext2fs_blocks_count(super) / i);
 235
 236         /*
 237          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 238          * that we have enough inodes for the filesystem(!)
 239          */
 240         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 241                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 242
 243         /*
 244          * There should be at least as many inodes as the user
 245          * requested.  Figure out how many inodes per group that
 246          * should be.  But make sure that we don't allocate more than
 247          * one bitmap's worth of inodes each group.
 248          */
 249         ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
 250         if (ipg > fs->blocksize * 8) {
 251                 if (super->s_blocks_per_group >= 256) {
 252                         /* Try again with slightly different parameters */
 253                         super->s_blocks_per_group -= 8;
 254                         ext2fs_blocks_count_set(super,
 255                                                 ext2fs_blocks_count(param));
 256                         super->s_frags_per_group = super->s_blocks_per_group *
 257                                 frags_per_block;
 258                         goto retry;
 259                 } else {
 260                         retval = EXT2_ET_TOO_MANY_INODES;
 261                         goto cleanup;
 262                 }
 263         }
 264
 265         if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
 266                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 267
 268 ipg_retry:
 269         super->s_inodes_per_group = ipg;
 270
 271         /*
 272          * Make sure the number of inodes per group completely fills
 273          * the inode table blocks in the descriptor.  If not, add some
 274          * additional inodes/group.  Waste not, want not...
 275          */
 276         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 277                                         EXT2_INODE_SIZE(super)) +
 278                                        EXT2_BLOCK_SIZE(super) - 1) /
 279                                       EXT2_BLOCK_SIZE(super));
 280         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 281                                       EXT2_BLOCK_SIZE(super)) /
 282                                      EXT2_INODE_SIZE(super));
 283         /*
 284          * Finally, make sure the number of inodes per group is a
 285          * multiple of 8.  This is needed to simplify the bitmap
 286          * splicing code.
 287          */
 288         super->s_inodes_per_group &= ~7;
 289         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 290                                         EXT2_INODE_SIZE(super)) +
 291                                        EXT2_BLOCK_SIZE(super) - 1) /
 292                                       EXT2_BLOCK_SIZE(super));
 293
 294         /*
 295          * adjust inode count to reflect the adjusted inodes_per_group
 296          */
 297         if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
 298                 ipg--;
 299                 goto ipg_retry;
 300         }
 301         super->s_inodes_count = super->s_inodes_per_group *
 302                 fs->group_desc_count;
 303         super->s_free_inodes_count = super->s_inodes_count;
 304
 305         /*
 306          * check the number of reserved group descriptor table blocks
 307          */
 308         if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
 309                 rsv_gdt = calc_reserved_gdt_blocks(fs);
 310         else
 311                 rsv_gdt = 0;
 312         set_field(s_reserved_gdt_blocks, rsv_gdt);
 313         if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
 314                 retval = EXT2_ET_RES_GDT_BLOCKS;
 315                 goto cleanup;
 316         }
 317
 318         /*
 319          * Calculate the maximum number of bookkeeping blocks per
 320          * group.  It includes the superblock, the block group
 321          * descriptors, the block bitmap, the inode bitmap, the inode
 322          * table, and the reserved gdt blocks.
 323          */
 324         overhead = (int) (3 + fs->inode_blocks_per_group +
 325                           fs->desc_blocks + super->s_reserved_gdt_blocks);
 326
 327         /* This can only happen if the user requested too many inodes */
 328         if (overhead > super->s_blocks_per_group) {
 329                 retval = EXT2_ET_TOO_MANY_INODES;
 330                 goto cleanup;
 331         }
 332
 333         /*
 334          * See if the last group is big enough to support the
 335          * necessary data structures.  If not, we need to get rid of
 336          * it.  We need to recalculate the overhead for the last block
 337          * group, since it might or might not have a superblock
 338          * backup.
 339          */
 340         overhead = (int) (2 + fs->inode_blocks_per_group);
 341         if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
 342                 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
 343         rem = ((ext2fs_blocks_count(super) - super->s_first_data_block) %
 344                super->s_blocks_per_group);
 345         if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
 346                 retval = EXT2_ET_TOOSMALL;
 347                 goto cleanup;
 348         }
 349         if (rem && (rem < overhead+50)) {
 350                 ext2fs_blocks_count_set(super, ext2fs_blocks_count(super) -
 351                                         rem);
 352
 353                 goto retry;
 354         }
 355
 356         /*
 357          * At this point we know how big the filesystem will be.  So
 358          * we can do any and all allocations that depend on the block
 359          * count.
 360          */
 361
 362         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 363         if (retval)
 364                 goto cleanup;
 365
 366         strcpy(buf, "block bitmap for ");
 367         strcat(buf, fs->device_name);
 368         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 369         if (retval)
 370                 goto cleanup;
 371
 372         strcpy(buf, "inode bitmap for ");
 373         strcat(buf, fs->device_name);
 374         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 375         if (retval)
 376                 goto cleanup;
 377
 378         ext2fs_free_mem(&buf);
 379
 380         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 381                                 &fs->group_desc);
 382         if (retval)
 383                 goto cleanup;
 384
 385         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 386
 387         /*
 388          * Reserve the superblock and group descriptors for each
 389          * group, and fill in the correct group statistics for group.
 390          * Note that although the block bitmap, inode bitmap, and
 391          * inode table have not been allocated (and in fact won't be
 392          * by this routine), they are accounted for nevertheless.
 393          *
 394          * If FLEX_BG meta-data grouping is used, only account for the
 395          * superblock and group descriptors (the inode tables and
 396          * bitmaps will be accounted for when allocated).
 397          */
 398         ext2fs_free_blocks_count_set(super, 0);
 399         csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 400                                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
 401         for (i = 0; i < fs->group_desc_count; i++) {
 402                 /*
 403                  * Don't set the BLOCK_UNINIT group for the last group
 404                  * because the block bitmap needs to be padded.
 405                  */
 406                 if (csum_flag) {
 407                         if (i != fs->group_desc_count - 1)
 408                                 ext2fs_bg_flags_set(fs, i,
 409                                                     EXT2_BG_BLOCK_UNINIT);
 410                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 411                         numblocks = super->s_inodes_per_group;
 412                         if (i == 0)
 413                                 numblocks -= super->s_first_ino;
 414                         ext2fs_bg_itable_unused_set(fs, i, numblocks);
 415                 }
 416                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 417                 if (fs->super->s_log_groups_per_flex)
 418                         numblocks += 2 + fs->inode_blocks_per_group;
 419
 420                 ext2fs_free_blocks_count_set(super,
 421                                              ext2fs_free_blocks_count(super) +
 422                                              numblocks);
 423                 ext2fs_bg_free_blocks_count_set(fs, i, numblocks);
 424                 ext2fs_bg_free_inodes_count_set(fs, i, fs->super->s_inodes_per_group);
 425                 ext2fs_bg_used_dirs_count_set(fs, i, 0);
 426                 ext2fs_group_desc_csum_set(fs, i);
 427         }
 428
 429         c = (char) 255;
 430         if (((int) c) == -1) {
 431                 super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
 432         } else {
 433                 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
 434         }
 435
 436         ext2fs_mark_super_dirty(fs);
 437         ext2fs_mark_bb_dirty(fs);
 438         ext2fs_mark_ib_dirty(fs);
 439
 440         io_channel_set_blksize(fs->io, fs->blocksize);
 441
 442         *ret_fs = fs;
 443         return 0;
 444 cleanup:
 445         free(buf);
 446         ext2fs_free(fs);
 447         return retval;
 448 }