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 (sb->s_blocks_count < max_blocks / 1024)
  66                 max_blocks = sb->s_blocks_count * 1024;
  67         rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
  68         rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks;
  69         if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
  70                 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
  71 #ifdef RES_GDT_DEBUG
  72         printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n",
  73                max_blocks, rsv_groups, rsv_gdb);
  74 #endif
  75
  76         return rsv_gdb;
  77 }
  78
  79 errcode_t ext2fs_initialize(const char *name, int flags,
  80                             struct ext2_super_block *param,
  81                             io_manager manager, ext2_filsys *ret_fs)
  82 {
  83         ext2_filsys     fs;
  84         errcode_t       retval;
  85         struct ext2_super_block *super;
  86         unsigned int    rem;
  87         unsigned int    overhead = 0;
  88         unsigned int    ipg;
  89         dgrp_t          i;
  90         blk_t           numblocks;
  91         int             rsv_gdt;
  92         int             csum_flag;
  93         int             io_flags;
  94         char            *buf = 0;
  95         char            c;
  96
  97         if (!param || !param->s_blocks_count)
  98                 return EXT2_ET_INVALID_ARGUMENT;
  99
 100         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 101         if (retval)
 102                 return retval;
 103
 104         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 105         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 106         fs->flags = flags | EXT2_FLAG_RW;
 107         fs->umask = 022;
 108 #ifdef WORDS_BIGENDIAN
 109         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 110 #endif
 111         io_flags = IO_FLAG_RW;
 112         if (flags & EXT2_FLAG_EXCLUSIVE)
 113                 io_flags |= IO_FLAG_EXCLUSIVE;
 114         retval = manager->open(name, io_flags, &fs->io);
 115         if (retval)
 116                 goto cleanup;
 117         fs->image_io = fs->io;
 118         fs->io->app_data = fs;
 119         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 120         if (retval)
 121                 goto cleanup;
 122
 123         strcpy(fs->device_name, name);
 124         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 125         if (retval)
 126                 goto cleanup;
 127         fs->super = super;
 128
 129         memset(super, 0, SUPERBLOCK_SIZE);
 130
 131 #define set_field(field, default) (super->field = param->field ? \
 132                                    param->field : (default))
 133
 134         super->s_magic = EXT2_SUPER_MAGIC;
 135         super->s_state = EXT2_VALID_FS;
 136
 137         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 138         set_field(s_log_cluster_size, 0);
 139         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 140         set_field(s_max_mnt_count, 0);
 141         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 142         set_field(s_feature_compat, 0);
 143         set_field(s_feature_incompat, 0);
 144         set_field(s_feature_ro_compat, 0);
 145         set_field(s_default_mount_opts, 0);
 146         set_field(s_first_meta_bg, 0);
 147         set_field(s_raid_stride, 0);            /* default stride size: 0 */
 148         set_field(s_raid_stripe_width, 0);      /* default stripe width: 0 */
 149         set_field(s_log_groups_per_flex, 0);
 150         set_field(s_flags, 0);
 151         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 152                 retval = EXT2_ET_UNSUPP_FEATURE;
 153                 goto cleanup;
 154         }
 155         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
 156                 retval = EXT2_ET_RO_UNSUPP_FEATURE;
 157                 goto cleanup;
 158         }
 159
 160         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 161         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 162                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 163                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 164                 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
 165                         int extra_isize = sizeof(struct ext2_inode_large) -
 166                                 EXT2_GOOD_OLD_INODE_SIZE;
 167                         set_field(s_min_extra_isize, extra_isize);
 168                         set_field(s_want_extra_isize, extra_isize);
 169                 }
 170         } else {
 171                 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 172                 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 173         }
 174
 175         set_field(s_checkinterval, 0);
 176         super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
 177
 178         super->s_creator_os = CREATOR_OS;
 179
 180         fs->blocksize = EXT2_BLOCK_SIZE(super);
 181         fs->clustersize = EXT2_CLUSTER_SIZE(super);
 182
 183         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 184         set_field(s_blocks_per_group, fs->blocksize * 8);
 185         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 186                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 187         super->s_clusters_per_group = super->s_blocks_per_group;
 188
 189         super->s_blocks_count = param->s_blocks_count;
 190         super->s_r_blocks_count = param->s_r_blocks_count;
 191         if (super->s_r_blocks_count >= param->s_blocks_count) {
 192                 retval = EXT2_ET_INVALID_ARGUMENT;
 193                 goto cleanup;
 194         }
 195
 196         /*
 197          * If we're creating an external journal device, we don't need
 198          * to bother with the rest.
 199          */
 200         if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 201                 fs->group_desc_count = 0;
 202                 ext2fs_mark_super_dirty(fs);
 203                 *ret_fs = fs;
 204                 return 0;
 205         }
 206
 207 retry:
 208         fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count -
 209                                                super->s_first_data_block,
 210                                                EXT2_BLOCKS_PER_GROUP(super));
 211         if (fs->group_desc_count == 0) {
 212                 retval = EXT2_ET_TOOSMALL;
 213                 goto cleanup;
 214         }
 215         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 216                                           EXT2_DESC_PER_BLOCK(super));
 217
 218         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 219         set_field(s_inodes_count, super->s_blocks_count / i);
 220
 221         /*
 222          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 223          * that we have enough inodes for the filesystem(!)
 224          */
 225         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 226                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 227
 228         /*
 229          * There should be at least as many inodes as the user
 230          * requested.  Figure out how many inodes per group that
 231          * should be.  But make sure that we don't allocate more than
 232          * one bitmap's worth of inodes each group.
 233          */
 234         ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
 235         if (ipg > fs->blocksize * 8) {
 236                 if (super->s_blocks_per_group >= 256) {
 237                         /* Try again with slightly different parameters */
 238                         super->s_blocks_per_group -= 8;
 239                         super->s_blocks_count = param->s_blocks_count;
 240                         super->s_clusters_per_group = super->s_blocks_per_group;
 241                         goto retry;
 242                 } else {
 243                         retval = EXT2_ET_TOO_MANY_INODES;
 244                         goto cleanup;
 245                 }
 246         }
 247
 248         if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
 249                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 250
 251 ipg_retry:
 252         super->s_inodes_per_group = ipg;
 253
 254         /*
 255          * Make sure the number of inodes per group completely fills
 256          * the inode table blocks in the descriptor.  If not, add some
 257          * additional inodes/group.  Waste not, want not...
 258          */
 259         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 260                                         EXT2_INODE_SIZE(super)) +
 261                                        EXT2_BLOCK_SIZE(super) - 1) /
 262                                       EXT2_BLOCK_SIZE(super));
 263         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 264                                       EXT2_BLOCK_SIZE(super)) /
 265                                      EXT2_INODE_SIZE(super));
 266         /*
 267          * Finally, make sure the number of inodes per group is a
 268          * multiple of 8.  This is needed to simplify the bitmap
 269          * splicing code.
 270          */
 271         super->s_inodes_per_group &= ~7;
 272         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 273                                         EXT2_INODE_SIZE(super)) +
 274                                        EXT2_BLOCK_SIZE(super) - 1) /
 275                                       EXT2_BLOCK_SIZE(super));
 276
 277         /*
 278          * adjust inode count to reflect the adjusted inodes_per_group
 279          */
 280         if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
 281                 ipg--;
 282                 goto ipg_retry;
 283         }
 284         super->s_inodes_count = super->s_inodes_per_group *
 285                 fs->group_desc_count;
 286         super->s_free_inodes_count = super->s_inodes_count;
 287
 288         /*
 289          * check the number of reserved group descriptor table blocks
 290          */
 291         if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
 292                 rsv_gdt = calc_reserved_gdt_blocks(fs);
 293         else
 294                 rsv_gdt = 0;
 295         set_field(s_reserved_gdt_blocks, rsv_gdt);
 296         if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
 297                 retval = EXT2_ET_RES_GDT_BLOCKS;
 298                 goto cleanup;
 299         }
 300
 301         /*
 302          * Calculate the maximum number of bookkeeping blocks per
 303          * group.  It includes the superblock, the block group
 304          * descriptors, the block bitmap, the inode bitmap, the inode
 305          * table, and the reserved gdt blocks.
 306          */
 307         overhead = (int) (3 + fs->inode_blocks_per_group +
 308                           fs->desc_blocks + super->s_reserved_gdt_blocks);
 309
 310         /* This can only happen if the user requested too many inodes */
 311         if (overhead > super->s_blocks_per_group) {
 312                 retval = EXT2_ET_TOO_MANY_INODES;
 313                 goto cleanup;
 314         }
 315
 316         /*
 317          * See if the last group is big enough to support the
 318          * necessary data structures.  If not, we need to get rid of
 319          * it.  We need to recalculate the overhead for the last block
 320          * group, since it might or might not have a superblock
 321          * backup.
 322          */
 323         overhead = (int) (2 + fs->inode_blocks_per_group);
 324         if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
 325                 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
 326         rem = ((super->s_blocks_count - super->s_first_data_block) %
 327                super->s_blocks_per_group);
 328         if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
 329                 retval = EXT2_ET_TOOSMALL;
 330                 goto cleanup;
 331         }
 332         if (rem && (rem < overhead+50)) {
 333                 super->s_blocks_count -= rem;
 334                 goto retry;
 335         }
 336
 337         /*
 338          * At this point we know how big the filesystem will be.  So
 339          * we can do any and all allocations that depend on the block
 340          * count.
 341          */
 342
 343         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 344         if (retval)
 345                 goto cleanup;
 346
 347         strcpy(buf, "block bitmap for ");
 348         strcat(buf, fs->device_name);
 349         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 350         if (retval)
 351                 goto cleanup;
 352
 353         strcpy(buf, "inode bitmap for ");
 354         strcat(buf, fs->device_name);
 355         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 356         if (retval)
 357                 goto cleanup;
 358
 359         ext2fs_free_mem(&buf);
 360
 361         retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
 362                                 &fs->group_desc);
 363         if (retval)
 364                 goto cleanup;
 365
 366         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 367
 368         /*
 369          * Reserve the superblock and group descriptors for each
 370          * group, and fill in the correct group statistics for group.
 371          * Note that although the block bitmap, inode bitmap, and
 372          * inode table have not been allocated (and in fact won't be
 373          * by this routine), they are accounted for nevertheless.
 374          *
 375          * If FLEX_BG meta-data grouping is used, only account for the
 376          * superblock and group descriptors (the inode tables and
 377          * bitmaps will be accounted for when allocated).
 378          */
 379         super->s_free_blocks_count = 0;
 380         csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 381                                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
 382         for (i = 0; i < fs->group_desc_count; i++) {
 383                 /*
 384                  * Don't set the BLOCK_UNINIT group for the last group
 385                  * because the block bitmap needs to be padded.
 386                  */
 387                 if (csum_flag) {
 388                         if (i != fs->group_desc_count - 1)
 389                                 fs->group_desc[i].bg_flags |=
 390                                         EXT2_BG_BLOCK_UNINIT;
 391                         fs->group_desc[i].bg_flags |= EXT2_BG_INODE_UNINIT;
 392                         numblocks = super->s_inodes_per_group;
 393                         if (i == 0)
 394                                 numblocks -= super->s_first_ino;
 395                         fs->group_desc[i].bg_itable_unused = numblocks;
 396                 }
 397                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 398                 if (fs->super->s_log_groups_per_flex)
 399                         numblocks += 2 + fs->inode_blocks_per_group;
 400
 401                 super->s_free_blocks_count += numblocks;
 402                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 403                 fs->group_desc[i].bg_free_inodes_count =
 404                         fs->super->s_inodes_per_group;
 405                 fs->group_desc[i].bg_used_dirs_count = 0;
 406                 ext2fs_group_desc_csum_set(fs, i);
 407         }
 408
 409         c = (char) 255;
 410         if (((int) c) == -1) {
 411                 super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
 412         } else {
 413                 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
 414         }
 415
 416         ext2fs_mark_super_dirty(fs);
 417         ext2fs_mark_bb_dirty(fs);
 418         ext2fs_mark_ib_dirty(fs);
 419
 420         io_channel_set_blksize(fs->io, fs->blocksize);
 421
 422         *ret_fs = fs;
 423         return 0;
 424 cleanup:
 425         free(buf);
 426         ext2fs_free(fs);
 427         return retval;
 428 }