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 "config.h"
  14 #include <stdio.h>
  15 #include <string.h>
  16 #if HAVE_UNISTD_H
  17 #include <unistd.h>
  18 #endif
  19 #include <fcntl.h>
  20 #include <time.h>
  21 #if HAVE_SYS_STAT_H
  22 #include <sys/stat.h>
  23 #endif
  24 #if HAVE_SYS_TYPES_H
  25 #include <sys/types.h>
  26 #endif
  27
  28 #include "ext2_fs.h"
  29 #include "ext2fs.h"
  30
  31 #if defined(__linux__)    &&    defined(EXT2_OS_LINUX)
  32 #define CREATOR_OS EXT2_OS_LINUX
  33 #else
  34 #if defined(__GNU__)     &&     defined(EXT2_OS_HURD)
  35 #define CREATOR_OS EXT2_OS_HURD
  36 #else
  37 #if defined(__FreeBSD__) &&     defined(EXT2_OS_FREEBSD)
  38 #define CREATOR_OS EXT2_OS_FREEBSD
  39 #else
  40 #if defined(LITES)         &&   defined(EXT2_OS_LITES)
  41 #define CREATOR_OS EXT2_OS_LITES
  42 #else
  43 #define CREATOR_OS EXT2_OS_LINUX /* by default */
  44 #endif /* defined(LITES) && defined(EXT2_OS_LITES) */
  45 #endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
  46 #endif /* defined(__GNU__)     && defined(EXT2_OS_HURD) */
  47 #endif /* defined(__linux__)   && defined(EXT2_OS_LINUX) */
  48
  49 /*
  50  * Calculate the number of GDT blocks to reserve for online filesystem growth.
  51  * The absolute maximum number of GDT blocks we can reserve is determined by
  52  * the number of block pointers that can fit into a single block.
  53  */
  54 static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs)
  55 {
  56         struct ext2_super_block *sb = fs->super;
  57         unsigned long bpg = sb->s_blocks_per_group;
  58         unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb);
  59         unsigned long max_blocks = 0xffffffff;
  60         unsigned long rsv_groups;
  61         unsigned int rsv_gdb;
  62
  63         /* We set it at 1024x the current filesystem size, or
  64          * the upper block count limit (2^32), whichever is lower.
  65          */
  66         if (ext2fs_blocks_count(sb) < max_blocks / 1024)
  67                 max_blocks = ext2fs_blocks_count(sb) * 1024;
  68         /*
  69          * ext2fs_div64_ceil() is unnecessary because max_blocks is
  70          * max _GDT_ blocks, which is limited to 32 bits.
  71          */
  72         rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
  73         rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks;
  74         if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
  75                 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
  76 #ifdef RES_GDT_DEBUG
  77         printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n",
  78                max_blocks, rsv_groups, rsv_gdb);
  79 #endif
  80
  81         return rsv_gdb;
  82 }
  83
  84 errcode_t ext2fs_initialize(const char *name, int flags,
  85                             struct ext2_super_block *param,
  86                             io_manager manager, ext2_filsys *ret_fs)
  87 {
  88         ext2_filsys     fs;
  89         errcode_t       retval;
  90         struct ext2_super_block *super;
  91         unsigned int    rem;
  92         unsigned int    overhead = 0;
  93         unsigned int    ipg;
  94         dgrp_t          i;
  95         blk64_t         free_blocks;
  96         blk_t           numblocks;
  97         int             rsv_gdt;
  98         int             csum_flag;
  99         int             bigalloc_flag;
 100         int             io_flags;
 101         char            *buf = 0;
 102         char            c;
 103
 104         if (!param || !ext2fs_blocks_count(param))
 105                 return EXT2_ET_INVALID_ARGUMENT;
 106
 107         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 108         if (retval)
 109                 return retval;
 110
 111         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 112         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 113         fs->flags = flags | EXT2_FLAG_RW;
 114         fs->umask = 022;
 115 #ifdef WORDS_BIGENDIAN
 116         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 117 #endif
 118         io_flags = IO_FLAG_RW;
 119         if (flags & EXT2_FLAG_EXCLUSIVE)
 120                 io_flags |= IO_FLAG_EXCLUSIVE;
 121         retval = manager->open(name, io_flags, &fs->io);
 122         if (retval)
 123                 goto cleanup;
 124         fs->image_io = fs->io;
 125         fs->io->app_data = fs;
 126         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 127         if (retval)
 128                 goto cleanup;
 129
 130         strcpy(fs->device_name, name);
 131         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 132         if (retval)
 133                 goto cleanup;
 134         fs->super = super;
 135
 136         memset(super, 0, SUPERBLOCK_SIZE);
 137
 138 #define set_field(field, default) (super->field = param->field ? \
 139                                    param->field : (default))
 140 #define assign_field(field)     (super->field = param->field)
 141
 142         super->s_magic = EXT2_SUPER_MAGIC;
 143         super->s_state = EXT2_VALID_FS;
 144
 145         bigalloc_flag = EXT2_HAS_RO_COMPAT_FEATURE(param,
 146                                    EXT4_FEATURE_RO_COMPAT_BIGALLOC);
 147
 148         assign_field(s_log_block_size);
 149
 150         if (bigalloc_flag) {
 151                 set_field(s_log_cluster_size, super->s_log_block_size+4);
 152                 if (super->s_log_block_size > super->s_log_cluster_size) {
 153                         retval = EXT2_ET_INVALID_ARGUMENT;
 154                         goto cleanup;
 155                 }
 156         } else
 157                 super->s_log_cluster_size = super->s_log_block_size;
 158
 159         set_field(s_first_data_block, super->s_log_cluster_size ? 0 : 1);
 160         set_field(s_max_mnt_count, 0);
 161         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 162         set_field(s_feature_compat, 0);
 163         set_field(s_feature_incompat, 0);
 164         set_field(s_feature_ro_compat, 0);
 165         set_field(s_default_mount_opts, 0);
 166         set_field(s_first_meta_bg, 0);
 167         set_field(s_raid_stride, 0);            /* default stride size: 0 */
 168         set_field(s_raid_stripe_width, 0);      /* default stripe width: 0 */
 169         set_field(s_log_groups_per_flex, 0);
 170         set_field(s_flags, 0);
 171         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 172                 retval = EXT2_ET_UNSUPP_FEATURE;
 173                 goto cleanup;
 174         }
 175         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
 176                 retval = EXT2_ET_RO_UNSUPP_FEATURE;
 177                 goto cleanup;
 178         }
 179
 180         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 181         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 182                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 183                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 184                 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
 185                         int extra_isize = sizeof(struct ext2_inode_large) -
 186                                 EXT2_GOOD_OLD_INODE_SIZE;
 187                         set_field(s_min_extra_isize, extra_isize);
 188                         set_field(s_want_extra_isize, extra_isize);
 189                 }
 190         } else {
 191                 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 192                 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 193         }
 194
 195         set_field(s_checkinterval, 0);
 196         super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
 197
 198         super->s_creator_os = CREATOR_OS;
 199
 200         fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(super);
 201         fs->cluster_ratio_bits = super->s_log_cluster_size -
 202                 super->s_log_block_size;
 203
 204         if (bigalloc_flag) {
 205                 if (param->s_blocks_per_group &&
 206                     param->s_clusters_per_group &&
 207                     ((param->s_clusters_per_group * EXT2FS_CLUSTER_RATIO(fs)) !=
 208                      param->s_blocks_per_group)) {
 209                         retval = EXT2_ET_INVALID_ARGUMENT;
 210                         goto cleanup;
 211                 }
 212                 if (param->s_clusters_per_group)
 213                         assign_field(s_clusters_per_group);
 214                 else if (param->s_blocks_per_group)
 215                         super->s_clusters_per_group =
 216                                 param->s_blocks_per_group /
 217                                 EXT2FS_CLUSTER_RATIO(fs);
 218                 else
 219                         super->s_clusters_per_group = fs->blocksize * 8;
 220                 if (super->s_clusters_per_group > EXT2_MAX_CLUSTERS_PER_GROUP(super))
 221                         super->s_clusters_per_group = EXT2_MAX_CLUSTERS_PER_GROUP(super);
 222                 super->s_blocks_per_group = EXT2FS_C2B(fs,
 223                                        super->s_clusters_per_group);
 224         } else {
 225                 set_field(s_blocks_per_group, fs->blocksize * 8);
 226                 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 227                         super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 228                 super->s_clusters_per_group = super->s_blocks_per_group;
 229         }
 230
 231         ext2fs_blocks_count_set(super, ext2fs_blocks_count(param) &
 232                                 ~((blk64_t) EXT2FS_CLUSTER_MASK(fs)));
 233         ext2fs_r_blocks_count_set(super, ext2fs_r_blocks_count(param));
 234         if (ext2fs_r_blocks_count(super) >= ext2fs_blocks_count(param)) {
 235                 retval = EXT2_ET_INVALID_ARGUMENT;
 236                 goto cleanup;
 237         }
 238
 239         /*
 240          * If we're creating an external journal device, we don't need
 241          * to bother with the rest.
 242          */
 243         if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 244                 fs->group_desc_count = 0;
 245                 ext2fs_mark_super_dirty(fs);
 246                 *ret_fs = fs;
 247                 return 0;
 248         }
 249
 250 retry:
 251         fs->group_desc_count = (blk_t) ext2fs_div64_ceil(
 252                 ext2fs_blocks_count(super) - super->s_first_data_block,
 253                 EXT2_BLOCKS_PER_GROUP(super));
 254         if (fs->group_desc_count == 0) {
 255                 retval = EXT2_ET_TOOSMALL;
 256                 goto cleanup;
 257         }
 258
 259         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT)
 260                 super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT;
 261
 262         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 263                                           EXT2_DESC_PER_BLOCK(super));
 264
 265         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 266
 267         if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT &&
 268             (ext2fs_blocks_count(super) / i) > (1ULL << 32))
 269                 set_field(s_inodes_count, ~0U);
 270         else
 271                 set_field(s_inodes_count, ext2fs_blocks_count(super) / i);
 272
 273         /*
 274          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 275          * that we have enough inodes for the filesystem(!)
 276          */
 277         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 278                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 279
 280         /*
 281          * There should be at least as many inodes as the user
 282          * requested.  Figure out how many inodes per group that
 283          * should be.  But make sure that we don't allocate more than
 284          * one bitmap's worth of inodes each group.
 285          */
 286         ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
 287         if (ipg > fs->blocksize * 8) {
 288                 if (!bigalloc_flag && super->s_blocks_per_group >= 256) {
 289                         /* Try again with slightly different parameters */
 290                         super->s_blocks_per_group -= 8;
 291                         ext2fs_blocks_count_set(super,
 292                                                 ext2fs_blocks_count(param));
 293                         super->s_clusters_per_group = super->s_blocks_per_group;
 294                         goto retry;
 295                 } else {
 296                         retval = EXT2_ET_TOO_MANY_INODES;
 297                         goto cleanup;
 298                 }
 299         }
 300
 301         if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
 302                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 303
 304 ipg_retry:
 305         super->s_inodes_per_group = ipg;
 306
 307         /*
 308          * Make sure the number of inodes per group completely fills
 309          * the inode table blocks in the descriptor.  If not, add some
 310          * additional inodes/group.  Waste not, want not...
 311          */
 312         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 313                                         EXT2_INODE_SIZE(super)) +
 314                                        EXT2_BLOCK_SIZE(super) - 1) /
 315                                       EXT2_BLOCK_SIZE(super));
 316         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 317                                       EXT2_BLOCK_SIZE(super)) /
 318                                      EXT2_INODE_SIZE(super));
 319         /*
 320          * Finally, make sure the number of inodes per group is a
 321          * multiple of 8.  This is needed to simplify the bitmap
 322          * splicing code.
 323          */
 324         if (super->s_inodes_per_group < 8)
 325                 super->s_inodes_per_group = 8;
 326         super->s_inodes_per_group &= ~7;
 327         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 328                                         EXT2_INODE_SIZE(super)) +
 329                                        EXT2_BLOCK_SIZE(super) - 1) /
 330                                       EXT2_BLOCK_SIZE(super));
 331
 332         /*
 333          * adjust inode count to reflect the adjusted inodes_per_group
 334          */
 335         if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
 336                 ipg--;
 337                 goto ipg_retry;
 338         }
 339         super->s_inodes_count = super->s_inodes_per_group *
 340                 fs->group_desc_count;
 341         super->s_free_inodes_count = super->s_inodes_count;
 342
 343         /*
 344          * check the number of reserved group descriptor table blocks
 345          */
 346         if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
 347                 rsv_gdt = calc_reserved_gdt_blocks(fs);
 348         else
 349                 rsv_gdt = 0;
 350         set_field(s_reserved_gdt_blocks, rsv_gdt);
 351         if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
 352                 retval = EXT2_ET_RES_GDT_BLOCKS;
 353                 goto cleanup;
 354         }
 355
 356         /*
 357          * Calculate the maximum number of bookkeeping blocks per
 358          * group.  It includes the superblock, the block group
 359          * descriptors, the block bitmap, the inode bitmap, the inode
 360          * table, and the reserved gdt blocks.
 361          */
 362         overhead = (int) (3 + fs->inode_blocks_per_group +
 363                           fs->desc_blocks + super->s_reserved_gdt_blocks);
 364
 365         /* This can only happen if the user requested too many inodes */
 366         if (overhead > super->s_blocks_per_group) {
 367                 retval = EXT2_ET_TOO_MANY_INODES;
 368                 goto cleanup;
 369         }
 370
 371         /*
 372          * See if the last group is big enough to support the
 373          * necessary data structures.  If not, we need to get rid of
 374          * it.  We need to recalculate the overhead for the last block
 375          * group, since it might or might not have a superblock
 376          * backup.
 377          */
 378         overhead = (int) (2 + fs->inode_blocks_per_group);
 379         if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
 380                 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
 381         rem = ((ext2fs_blocks_count(super) - super->s_first_data_block) %
 382                super->s_blocks_per_group);
 383         if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
 384                 retval = EXT2_ET_TOOSMALL;
 385                 goto cleanup;
 386         }
 387         if (rem && (rem < overhead+50)) {
 388                 ext2fs_blocks_count_set(super, ext2fs_blocks_count(super) -
 389                                         rem);
 390
 391                 goto retry;
 392         }
 393
 394         /*
 395          * At this point we know how big the filesystem will be.  So
 396          * we can do any and all allocations that depend on the block
 397          * count.
 398          */
 399
 400         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 401         if (retval)
 402                 goto cleanup;
 403
 404         strcpy(buf, "block bitmap for ");
 405         strcat(buf, fs->device_name);
 406         retval = ext2fs_allocate_subcluster_bitmap(fs, buf, &fs->block_map);
 407         if (retval)
 408                 goto cleanup;
 409
 410         strcpy(buf, "inode bitmap for ");
 411         strcat(buf, fs->device_name);
 412         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 413         if (retval)
 414                 goto cleanup;
 415
 416         ext2fs_free_mem(&buf);
 417
 418         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 419                                 &fs->group_desc);
 420         if (retval)
 421                 goto cleanup;
 422
 423         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 424
 425         /*
 426          * Reserve the superblock and group descriptors for each
 427          * group, and fill in the correct group statistics for group.
 428          * Note that although the block bitmap, inode bitmap, and
 429          * inode table have not been allocated (and in fact won't be
 430          * by this routine), they are accounted for nevertheless.
 431          *
 432          * If FLEX_BG meta-data grouping is used, only account for the
 433          * superblock and group descriptors (the inode tables and
 434          * bitmaps will be accounted for when allocated).
 435          */
 436         free_blocks = 0;
 437         csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 438                                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
 439         for (i = 0; i < fs->group_desc_count; i++) {
 440                 /*
 441                  * Don't set the BLOCK_UNINIT group for the last group
 442                  * because the block bitmap needs to be padded.
 443                  */
 444                 if (csum_flag) {
 445                         if (i != fs->group_desc_count - 1)
 446                                 ext2fs_bg_flags_set(fs, i,
 447                                                     EXT2_BG_BLOCK_UNINIT);
 448                         ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
 449                         numblocks = super->s_inodes_per_group;
 450                         if (i == 0)
 451                                 numblocks -= super->s_first_ino;
 452                         ext2fs_bg_itable_unused_set(fs, i, numblocks);
 453                 }
 454                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 455                 if (fs->super->s_log_groups_per_flex)
 456                         numblocks += 2 + fs->inode_blocks_per_group;
 457
 458                 free_blocks += numblocks;
 459                 ext2fs_bg_free_blocks_count_set(fs, i, numblocks);
 460                 ext2fs_bg_free_inodes_count_set(fs, i, fs->super->s_inodes_per_group);
 461                 ext2fs_bg_used_dirs_count_set(fs, i, 0);
 462                 ext2fs_group_desc_csum_set(fs, i);
 463         }
 464         free_blocks &= ~EXT2FS_CLUSTER_MASK(fs);
 465         ext2fs_free_blocks_count_set(super, free_blocks);
 466
 467         c = (char) 255;
 468         if (((int) c) == -1) {
 469                 super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
 470         } else {
 471                 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
 472         }
 473
 474         ext2fs_mark_super_dirty(fs);
 475         ext2fs_mark_bb_dirty(fs);
 476         ext2fs_mark_ib_dirty(fs);
 477
 478         io_channel_set_blksize(fs->io, fs->blocksize);
 479
 480         *ret_fs = fs;
 481         return 0;
 482 cleanup:
 483         free(buf);
 484         ext2fs_free(fs);
 485         return retval;
 486 }