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