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 #elif defined(__GNU__)     &&   defined(EXT2_OS_HURD)
  33 #define CREATOR_OS EXT2_OS_HURD
  34 #elif defined(__FreeBSD__) &&   defined(EXT2_OS_FREEBSD)
  35 #define CREATOR_OS EXT2_OS_FREEBSD
  36 #elif defined(LITES)       &&   defined(EXT2_OS_LITES)
  37 #define CREATOR_OS EXT2_OS_LITES
  38 #else
  39 #define CREATOR_OS EXT2_OS_LINUX /* by default */
  40 #endif
  41
  42 /*
  43  * Note we override the kernel include file's idea of what the default
  44  * check interval (never) should be.  It's a good idea to check at
  45  * least *occasionally*, specially since servers will never rarely get
  46  * to reboot, since Linux is so robust these days.  :-)
  47  *
  48  * 180 days (six months) seems like a good value.
  49  */
  50 #ifdef EXT2_DFL_CHECKINTERVAL
  51 #undef EXT2_DFL_CHECKINTERVAL
  52 #endif
  53 #define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
  54
  55 errcode_t ext2fs_initialize(const char *name, int flags,
  56                             struct ext2_super_block *param,
  57                             io_manager manager, ext2_filsys *ret_fs)
  58 {
  59         ext2_filsys     fs;
  60         errcode_t       retval;
  61         struct ext2_super_block *super;
  62         int             frags_per_block;
  63         int             rem;
  64         int             overhead = 0;
  65         blk_t           group_block;
  66         int             ipg;
  67         int             i, j;
  68         blk_t           numblocks;
  69         char            *buf;
  70         int             meta_bg_size, meta_bg, has_super;
  71
  72         if (!param || !param->s_blocks_count)
  73                 return EXT2_ET_INVALID_ARGUMENT;
  74
  75         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys),
  76                                 (void **) &fs);
  77         if (retval)
  78                 return retval;
  79
  80         memset(fs, 0, sizeof(struct struct_ext2_filsys));
  81         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
  82         fs->flags = flags | EXT2_FLAG_RW;
  83         fs->umask = 022;
  84 #ifdef WORDS_BIGENDIAN
  85         fs->flags |= EXT2_FLAG_SWAP_BYTES;
  86 #endif
  87         retval = manager->open(name, IO_FLAG_RW, &fs->io);
  88         if (retval)
  89                 goto cleanup;
  90         fs->io->app_data = fs;
  91         retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name);
  92         if (retval)
  93                 goto cleanup;
  94
  95         strcpy(fs->device_name, name);
  96         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super);
  97         if (retval)
  98                 goto cleanup;
  99         fs->super = super;
 100
 101         memset(super, 0, SUPERBLOCK_SIZE);
 102
 103 #define set_field(field, default) (super->field = param->field ? \
 104                                    param->field : (default))
 105
 106         super->s_magic = EXT2_SUPER_MAGIC;
 107         super->s_state = EXT2_VALID_FS;
 108
 109         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 110         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 111         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 112         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 113         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 114         set_field(s_feature_compat, 0);
 115         set_field(s_feature_incompat, 0);
 116         set_field(s_feature_ro_compat, 0);
 117         set_field(s_first_meta_bg, 0);
 118         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
 119                 return EXT2_ET_UNSUPP_FEATURE;
 120         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
 121                 return EXT2_ET_RO_UNSUPP_FEATURE;
 122
 123         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 124         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 125                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 126                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 127         }
 128
 129         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 130         super->s_mkfs_time = super->s_lastcheck = time(NULL);
 131
 132         super->s_creator_os = CREATOR_OS;
 133
 134         fs->blocksize = EXT2_BLOCK_SIZE(super);
 135         fs->fragsize = EXT2_FRAG_SIZE(super);
 136         frags_per_block = fs->blocksize / fs->fragsize;
 137
 138         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 139         set_field(s_blocks_per_group, fs->blocksize * 8);
 140         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 141                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 142         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 143
 144         super->s_blocks_count = param->s_blocks_count;
 145         super->s_r_blocks_count = param->s_r_blocks_count;
 146         if (super->s_r_blocks_count >= param->s_blocks_count) {
 147                 retval = EXT2_ET_INVALID_ARGUMENT;
 148                 goto cleanup;
 149         }
 150
 151         /*
 152          * If we're creating an external journal device, we don't need
 153          * to bother with the rest.
 154          */
 155         if (super->s_feature_incompat &
 156             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 157                 fs->group_desc_count = 0;
 158                 ext2fs_mark_super_dirty(fs);
 159                 *ret_fs = fs;
 160                 return 0;
 161         }
 162
 163 retry:
 164         fs->group_desc_count = (super->s_blocks_count -
 165                                 super->s_first_data_block +
 166                                 EXT2_BLOCKS_PER_GROUP(super) - 1)
 167                 / EXT2_BLOCKS_PER_GROUP(super);
 168         if (fs->group_desc_count == 0)
 169                 return EXT2_ET_TOOSMALL;
 170         fs->desc_blocks = (fs->group_desc_count +
 171                            EXT2_DESC_PER_BLOCK(super) - 1)
 172                 / EXT2_DESC_PER_BLOCK(super);
 173
 174         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 175         set_field(s_inodes_count, super->s_blocks_count / i);
 176
 177         /*
 178          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 179          * that we have enough inodes for the filesystem(!)
 180          */
 181         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 182                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 183
 184         /*
 185          * There should be at least as many inodes as the user
 186          * requested.  Figure out how many inodes per group that
 187          * should be.  But make sure that we don't allocate more than
 188          * one bitmap's worth of inodes each group.
 189          */
 190         ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
 191                 fs->group_desc_count;
 192         if (ipg > fs->blocksize * 8)
 193                 ipg = fs->blocksize * 8;
 194
 195         if (ipg > EXT2_MAX_INODES_PER_GROUP(super))
 196                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 197
 198         super->s_inodes_per_group = ipg;
 199         if (super->s_inodes_count > ipg * fs->group_desc_count)
 200                 super->s_inodes_count = ipg * fs->group_desc_count;
 201
 202         /*
 203          * Make sure the number of inodes per group completely fills
 204          * the inode table blocks in the descriptor.  If not, add some
 205          * additional inodes/group.  Waste not, want not...
 206          */
 207         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 208                                         EXT2_INODE_SIZE(super)) +
 209                                        EXT2_BLOCK_SIZE(super) - 1) /
 210                                       EXT2_BLOCK_SIZE(super));
 211         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 212                                       EXT2_BLOCK_SIZE(super)) /
 213                                      EXT2_INODE_SIZE(super));
 214         /*
 215          * Finally, make sure the number of inodes per group is a
 216          * multiple of 8.  This is needed to simplify the bitmap
 217          * splicing code.
 218          */
 219         super->s_inodes_per_group &= ~7;
 220         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 221                                         EXT2_INODE_SIZE(super)) +
 222                                        EXT2_BLOCK_SIZE(super) - 1) /
 223                                       EXT2_BLOCK_SIZE(super));
 224
 225         /*
 226          * adjust inode count to reflect the adjusted inodes_per_group
 227          */
 228         super->s_inodes_count = super->s_inodes_per_group *
 229                 fs->group_desc_count;
 230         super->s_free_inodes_count = super->s_inodes_count;
 231
 232         /*
 233          * Overhead is the number of bookkeeping blocks per group.  It
 234          * includes the superblock backup, the group descriptor
 235          * backups, the inode bitmap, the block bitmap, and the inode
 236          * table.
 237          *
 238          * XXX Not all block groups need the descriptor blocks, but
 239          * being clever is tricky...
 240          */
 241         overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group);
 242
 243         /*
 244          * See if the last group is big enough to support the
 245          * necessary data structures.  If not, we need to get rid of
 246          * it.
 247          */
 248         rem = (int) ((super->s_blocks_count - super->s_first_data_block) %
 249                      super->s_blocks_per_group);
 250         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 251                 return EXT2_ET_TOOSMALL;
 252         if (rem && (rem < overhead+50)) {
 253                 super->s_blocks_count -= rem;
 254                 goto retry;
 255         }
 256
 257         /*
 258          * At this point we know how big the filesystem will be.  So
 259          * we can do any and all allocations that depend on the block
 260          * count.
 261          */
 262
 263         retval = ext2fs_get_mem(strlen(fs->device_name) + 80,
 264                                 (void **) &buf);
 265         if (retval)
 266                 goto cleanup;
 267
 268         sprintf(buf, "block bitmap for %s", fs->device_name);
 269         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 270         if (retval)
 271                 goto cleanup;
 272
 273         sprintf(buf, "inode bitmap for %s", fs->device_name);
 274         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 275         if (retval)
 276                 goto cleanup;
 277
 278         ext2fs_free_mem((void **) &buf);
 279
 280         retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
 281                                 (void **) &fs->group_desc);
 282         if (retval)
 283                 goto cleanup;
 284
 285         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 286
 287         /*
 288          * Reserve the superblock and group descriptors for each
 289          * group, and fill in the correct group statistics for group.
 290          * Note that although the block bitmap, inode bitmap, and
 291          * inode table have not been allocated (and in fact won't be
 292          * by this routine), they are accounted for nevertheless.
 293          */
 294         group_block = super->s_first_data_block;
 295         super->s_free_blocks_count = 0;
 296         for (i = 0; i < fs->group_desc_count; i++) {
 297                 if (i == fs->group_desc_count-1) {
 298                         numblocks = (fs->super->s_blocks_count -
 299                                      fs->super->s_first_data_block) %
 300                                              fs->super->s_blocks_per_group;
 301                         if (!numblocks)
 302                                 numblocks = fs->super->s_blocks_per_group;
 303                 } else
 304                         numblocks = fs->super->s_blocks_per_group;
 305
 306                 has_super = ext2fs_bg_has_super(fs, i);
 307
 308                 if (has_super) {
 309                         ext2fs_mark_block_bitmap(fs->block_map, group_block);
 310                         numblocks--;
 311                 }
 312                 meta_bg_size = (fs->blocksize /
 313                                 sizeof (struct ext2_group_desc));
 314                 meta_bg = i / meta_bg_size;
 315
 316                 if (!(fs->super->s_feature_incompat &
 317                       EXT2_FEATURE_INCOMPAT_META_BG) ||
 318                     (meta_bg < fs->super->s_first_meta_bg)) {
 319                         if (has_super) {
 320                                 for (j=0; j < fs->desc_blocks; j++)
 321                                         ext2fs_mark_block_bitmap(fs->block_map,
 322                                                          group_block + j + 1);
 323                                 numblocks -= fs->desc_blocks;
 324                         }
 325                 } else {
 326                         if (has_super)
 327                                 has_super = 1;
 328                         if (((i % meta_bg_size) == 0) ||
 329                             ((i % meta_bg_size) == 1) ||
 330                             ((i % meta_bg_size) == (meta_bg_size-1))) {
 331                                 ext2fs_mark_block_bitmap(fs->block_map,
 332                                          group_block + has_super);
 333                                 numblocks--;
 334                         }
 335                 }
 336
 337                 numblocks -= 2 + fs->inode_blocks_per_group;
 338
 339                 super->s_free_blocks_count += numblocks;
 340                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 341                 fs->group_desc[i].bg_free_inodes_count =
 342                         fs->super->s_inodes_per_group;
 343                 fs->group_desc[i].bg_used_dirs_count = 0;
 344
 345                 group_block += super->s_blocks_per_group;
 346         }
 347
 348         ext2fs_mark_super_dirty(fs);
 349         ext2fs_mark_bb_dirty(fs);
 350         ext2fs_mark_ib_dirty(fs);
 351
 352         io_channel_set_blksize(fs->io, fs->blocksize);
 353
 354         *ret_fs = fs;
 355         return 0;
 356 cleanup:
 357         ext2fs_free(fs);
 358         return retval;
 359 }
 360
 361
 362