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  * Note we override the kernel include file's idea of what the default
  50  * check interval (never) should be.  It's a good idea to check at
  51  * least *occasionally*, specially since servers will never rarely get
  52  * to reboot, since Linux is so robust these days.  :-)
  53  *
  54  * 180 days (six months) seems like a good value.
  55  */
  56 #ifdef EXT2_DFL_CHECKINTERVAL
  57 #undef EXT2_DFL_CHECKINTERVAL
  58 #endif
  59 #define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
  60
  61 /*
  62  * Calculate the number of GDT blocks to reserve for online filesystem growth.
  63  * The absolute maximum number of GDT blocks we can reserve is determined by
  64  * the number of block pointers that can fit into a single block.
  65  */
  66 static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs)
  67 {
  68         struct ext2_super_block *sb = fs->super;
  69         unsigned long bpg = sb->s_blocks_per_group;
  70         unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb);
  71         unsigned long max_blocks = 0xffffffff;
  72         unsigned long rsv_groups;
  73         unsigned int rsv_gdb;
  74
  75         /* We set it at 1024x the current filesystem size, or
  76          * the upper block count limit (2^32), whichever is lower.
  77          */
  78         if (ext2fs_blocks_count(sb) < max_blocks / 1024)
  79                 max_blocks = ext2fs_blocks_count(sb) * 1024;
  80         /*
  81          * ext2fs_div64_ceil() is unnecessary because max_blocks is
  82          * max _GDT_ blocks, which is limited to 32 bits.
  83          */
  84         rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
  85         rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks;
  86         if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
  87                 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
  88 #ifdef RES_GDT_DEBUG
  89         printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n",
  90                max_blocks, rsv_groups, rsv_gdb);
  91 #endif
  92
  93         return rsv_gdb;
  94 }
  95
  96 errcode_t ext2fs_initialize(const char *name, int flags,
  97                             struct ext2_super_block *param,
  98                             io_manager manager, ext2_filsys *ret_fs)
  99 {
 100         ext2_filsys     fs;
 101         errcode_t       retval;
 102         struct ext2_super_block *super;
 103         int             frags_per_block;
 104         unsigned int    rem;
 105         unsigned int    overhead = 0;
 106         unsigned int    ipg;
 107         dgrp_t          i;
 108         blk_t           numblocks;
 109         int             rsv_gdt;
 110         int             csum_flag;
 111         int             io_flags;
 112         char            *buf = 0;
 113         char            c;
 114
 115         if (!param || !ext2fs_blocks_count(param))
 116                 return EXT2_ET_INVALID_ARGUMENT;
 117
 118         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 119         if (retval)
 120                 return retval;
 121
 122         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 123         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 124         fs->flags = flags | EXT2_FLAG_RW;
 125         fs->umask = 022;
 126 #ifdef WORDS_BIGENDIAN
 127         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 128 #endif
 129         io_flags = IO_FLAG_RW;
 130         if (flags & EXT2_FLAG_EXCLUSIVE)
 131                 io_flags |= IO_FLAG_EXCLUSIVE;
 132         retval = manager->open(name, io_flags, &fs->io);
 133         if (retval)
 134                 goto cleanup;
 135         fs->image_io = fs->io;
 136         fs->io->app_data = fs;
 137         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 138         if (retval)
 139                 goto cleanup;
 140
 141         strcpy(fs->device_name, name);
 142         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 143         if (retval)
 144                 goto cleanup;
 145         fs->super = super;
 146
 147         memset(super, 0, SUPERBLOCK_SIZE);
 148
 149 #define set_field(field, default) (super->field = param->field ? \
 150                                    param->field : (default))
 151
 152         super->s_magic = EXT2_SUPER_MAGIC;
 153         super->s_state = EXT2_VALID_FS;
 154
 155         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 156         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 157         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 158         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 159         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 160         set_field(s_feature_compat, 0);
 161         set_field(s_feature_incompat, 0);
 162         set_field(s_feature_ro_compat, 0);
 163         set_field(s_first_meta_bg, 0);
 164         set_field(s_raid_stride, 0);            /* default stride size: 0 */
 165         set_field(s_raid_stripe_width, 0);      /* default stripe width: 0 */
 166         set_field(s_log_groups_per_flex, 0);
 167         set_field(s_flags, 0);
 168         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 169                 retval = EXT2_ET_UNSUPP_FEATURE;
 170                 goto cleanup;
 171         }
 172         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
 173                 retval = EXT2_ET_RO_UNSUPP_FEATURE;
 174                 goto cleanup;
 175         }
 176
 177         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 178         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 179                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 180                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 181                 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
 182                         int extra_isize = sizeof(struct ext2_inode_large) -
 183                                 EXT2_GOOD_OLD_INODE_SIZE;
 184                         set_field(s_min_extra_isize, extra_isize);
 185                         set_field(s_want_extra_isize, extra_isize);
 186                 }
 187         } else {
 188                 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 189                 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 190         }
 191
 192         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 193         super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
 194
 195         super->s_creator_os = CREATOR_OS;
 196
 197         fs->blocksize = EXT2_BLOCK_SIZE(super);
 198         fs->fragsize = EXT2_FRAG_SIZE(super);
 199         frags_per_block = fs->blocksize / fs->fragsize;
 200
 201         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 202         set_field(s_blocks_per_group, fs->blocksize * 8);
 203         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 204                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 205         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 206
 207         ext2fs_blocks_count_set(super, ext2fs_blocks_count(param));
 208         ext2fs_r_blocks_count_set(super, ext2fs_r_blocks_count(param));
 209         if (ext2fs_r_blocks_count(super) >= ext2fs_blocks_count(param)) {
 210                 retval = EXT2_ET_INVALID_ARGUMENT;
 211                 goto cleanup;
 212         }
 213
 214         /*
 215          * If we're creating an external journal device, we don't need
 216          * to bother with the rest.
 217          */
 218         if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 219                 fs->group_desc_count = 0;
 220                 ext2fs_mark_super_dirty(fs);
 221                 *ret_fs = fs;
 222                 return 0;
 223         }
 224
 225 retry:
 226         fs->group_desc_count = (blk_t) ext2fs_div64_ceil(
 227                 ext2fs_blocks_count(super) - super->s_first_data_block,
 228                 EXT2_BLOCKS_PER_GROUP(super));
 229         if (fs->group_desc_count == 0) {
 230                 retval = EXT2_ET_TOOSMALL;
 231                 goto cleanup;
 232         }
 233
 234         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT)
 235                 super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT;
 236
 237         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 238                                           EXT2_DESC_PER_BLOCK(super));
 239
 240         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 241
 242         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT &&
 243             (ext2fs_blocks_count(super) / i) > (1ULL << 32))
 244                 set_field(s_inodes_count, ~0U);
 245         else
 246                 set_field(s_inodes_count, ext2fs_blocks_count(super) / i);
 247
 248         /*
 249          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 250          * that we have enough inodes for the filesystem(!)
 251          */
 252         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 253                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 254
 255         /*
 256          * There should be at least as many inodes as the user
 257          * requested.  Figure out how many inodes per group that
 258          * should be.  But make sure that we don't allocate more than
 259          * one bitmap's worth of inodes each group.
 260          */
 261         ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
 262         if (ipg > fs->blocksize * 8) {
 263                 if (super->s_blocks_per_group >= 256) {
 264                         /* Try again with slightly different parameters */
 265                         super->s_blocks_per_group -= 8;
 266                         ext2fs_blocks_count_set(super,
 267                                                 ext2fs_blocks_count(param));
 268                         super->s_frags_per_group = super->s_blocks_per_group *
 269                                 frags_per_block;
 270                         goto retry;
 271                 } else {
 272                         retval = EXT2_ET_TOO_MANY_INODES;
 273                         goto cleanup;
 274                 }
 275         }
 276
 277         if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
 278                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 279
 280 ipg_retry:
 281         super->s_inodes_per_group = ipg;
 282
 283         /*
 284          * Make sure the number of inodes per group completely fills
 285          * the inode table blocks in the descriptor.  If not, add some
 286          * additional inodes/group.  Waste not, want not...
 287          */
 288         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 289                                         EXT2_INODE_SIZE(super)) +
 290                                        EXT2_BLOCK_SIZE(super) - 1) /
 291                                       EXT2_BLOCK_SIZE(super));
 292         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 293                                       EXT2_BLOCK_SIZE(super)) /
 294                                      EXT2_INODE_SIZE(super));
 295         /*
 296          * Finally, make sure the number of inodes per group is a
 297          * multiple of 8.  This is needed to simplify the bitmap
 298          * splicing code.
 299          */
 300         super->s_inodes_per_group &= ~7;
 301         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 302                                         EXT2_INODE_SIZE(super)) +
 303                                        EXT2_BLOCK_SIZE(super) - 1) /
 304                                       EXT2_BLOCK_SIZE(super));
 305
 306         /*
 307          * adjust inode count to reflect the adjusted inodes_per_group
 308          */
 309         if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
 310                 ipg--;
 311                 goto ipg_retry;
 312         }
 313         super->s_inodes_count = super->s_inodes_per_group *
 314                 fs->group_desc_count;
 315         super->s_free_inodes_count = super->s_inodes_count;
 316
 317         /*
 318          * check the number of reserved group descriptor table blocks
 319          */
 320         if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
 321                 rsv_gdt = calc_reserved_gdt_blocks(fs);
 322         else
 323                 rsv_gdt = 0;
 324         set_field(s_reserved_gdt_blocks, rsv_gdt);
 325         if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
 326                 retval = EXT2_ET_RES_GDT_BLOCKS;
 327                 goto cleanup;
 328         }
 329
 330         /*
 331          * Calculate the maximum number of bookkeeping blocks per
 332          * group.  It includes the superblock, the block group
 333          * descriptors, the block bitmap, the inode bitmap, the inode
 334          * table, and the reserved gdt blocks.
 335          */
 336         overhead = (int) (3 + fs->inode_blocks_per_group +
 337                           fs->desc_blocks + super->s_reserved_gdt_blocks);
 338
 339         /* This can only happen if the user requested too many inodes */
 340         if (overhead > super->s_blocks_per_group) {
 341                 retval = EXT2_ET_TOO_MANY_INODES;
 342                 goto cleanup;
 343         }
 344
 345         /*
 346          * See if the last group is big enough to support the
 347          * necessary data structures.  If not, we need to get rid of
 348          * it.  We need to recalculate the overhead for the last block
 349          * group, since it might or might not have a superblock
 350          * backup.
 351          */
 352         overhead = (int) (2 + fs->inode_blocks_per_group);
 353         if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
 354                 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
 355         rem = ((ext2fs_blocks_count(super) - super->s_first_data_block) %
 356                super->s_blocks_per_group);
 357         if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
 358                 retval = EXT2_ET_TOOSMALL;
 359                 goto cleanup;
 360         }
 361         if (rem && (rem < overhead+50)) {
 362                 ext2fs_blocks_count_set(super, ext2fs_blocks_count(super) -
 363                                         rem);
 364
 365                 goto retry;
 366         }
 367
 368         /*
 369          * At this point we know how big the filesystem will be.  So
 370          * we can do any and all allocations that depend on the block
 371          * count.
 372          */
 373
 374         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 375         if (retval)
 376                 goto cleanup;
 377
 378         strcpy(buf, "block bitmap for ");
 379         strcat(buf, fs->device_name);
 380         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 381         if (retval)
 382                 goto cleanup;
 383
 384         strcpy(buf, "inode bitmap for ");
 385         strcat(buf, fs->device_name);
 386         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 387         if (retval)
 388                 goto cleanup;
 389
 390         ext2fs_free_mem(&buf);
 391
 392         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 393                                 &fs->group_desc);
 394         if (retval)
 395                 goto cleanup;
 396
 397         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 398
 399         /*
 400          * Reserve the superblock and group descriptors for each
 401          * group, and fill in the correct group statistics for group.
 402          * Note that although the block bitmap, inode bitmap, and
 403          * inode table have not been allocated (and in fact won't be
 404          * by this routine), they are accounted for nevertheless.
 405          *
 406          * If FLEX_BG meta-data grouping is used, only account for the
 407          * superblock and group descriptors (the inode tables and
 408          * bitmaps will be accounted for when allocated).
 409          */
 410         ext2fs_free_blocks_count_set(super, 0);
 411         csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 412                                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
 413         for (i = 0; i < fs->group_desc_count; i++) {
 414                 /*
 415                  * Don't set the BLOCK_UNINIT group for the last group
 416                  * because the block bitmap needs to be padded.
 417                  */
 418                 if (csum_flag) {
 419                         if (i != fs->group_desc_count - 1)
 420                                 ext2fs_bg_flags_set(fs, i,
 421                                                     EXT2_BG_BLOCK_UNINIT);
 422                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 423                         numblocks = super->s_inodes_per_group;
 424                         if (i == 0)
 425                                 numblocks -= super->s_first_ino;
 426                         ext2fs_bg_itable_unused_set(fs, i, numblocks);
 427                 }
 428                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 429                 if (fs->super->s_log_groups_per_flex)
 430                         numblocks += 2 + fs->inode_blocks_per_group;
 431
 432                 ext2fs_free_blocks_count_set(super,
 433                                              ext2fs_free_blocks_count(super) +
 434                                              numblocks);
 435                 ext2fs_bg_free_blocks_count_set(fs, i, numblocks);
 436                 ext2fs_bg_free_inodes_count_set(fs, i, fs->super->s_inodes_per_group);
 437                 ext2fs_bg_used_dirs_count_set(fs, i, 0);
 438                 ext2fs_group_desc_csum_set(fs, i);
 439         }
 440
 441         c = (char) 255;
 442         if (((int) c) == -1) {
 443                 super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
 444         } else {
 445                 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
 446         }
 447
 448         ext2fs_mark_super_dirty(fs);
 449         ext2fs_mark_bb_dirty(fs);
 450         ext2fs_mark_ib_dirty(fs);
 451
 452         io_channel_set_blksize(fs->io, fs->blocksize);
 453
 454         *ret_fs = fs;
 455         return 0;
 456 cleanup:
 457         free(buf);
 458         ext2fs_free(fs);
 459         return retval;
 460 }