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 errcode_t ext2fs_initialize(const char *name, int flags,
  62                             struct ext2_super_block *param,
  63                             io_manager manager, ext2_filsys *ret_fs)
  64 {
  65         ext2_filsys     fs;
  66         errcode_t       retval;
  67         struct ext2_super_block *super;
  68         int             frags_per_block;
  69         int             rem;
  70         int             overhead = 0;
  71         blk_t           group_block;
  72         int             ipg;
  73         int             i, j;
  74         blk_t           numblocks;
  75         char            *buf;
  76         int             meta_bg_size, meta_bg, has_super, old_desc_blocks;
  77
  78         if (!param || !param->s_blocks_count)
  79                 return EXT2_ET_INVALID_ARGUMENT;
  80
  81         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys),
  82                                 (void **) &fs);
  83         if (retval)
  84                 return retval;
  85
  86         memset(fs, 0, sizeof(struct struct_ext2_filsys));
  87         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
  88         fs->flags = flags | EXT2_FLAG_RW;
  89         fs->umask = 022;
  90 #ifdef WORDS_BIGENDIAN
  91         fs->flags |= EXT2_FLAG_SWAP_BYTES;
  92 #endif
  93         retval = manager->open(name, IO_FLAG_RW, &fs->io);
  94         if (retval)
  95                 goto cleanup;
  96         fs->io->app_data = fs;
  97         retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name);
  98         if (retval)
  99                 goto cleanup;
 100
 101         strcpy(fs->device_name, name);
 102         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super);
 103         if (retval)
 104                 goto cleanup;
 105         fs->super = super;
 106
 107         memset(super, 0, SUPERBLOCK_SIZE);
 108
 109 #define set_field(field, default) (super->field = param->field ? \
 110                                    param->field : (default))
 111
 112         super->s_magic = EXT2_SUPER_MAGIC;
 113         super->s_state = EXT2_VALID_FS;
 114
 115         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 116         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 117         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 118         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 119         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 120         set_field(s_feature_compat, 0);
 121         set_field(s_feature_incompat, 0);
 122         set_field(s_feature_ro_compat, 0);
 123         set_field(s_first_meta_bg, 0);
 124         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
 125                 return EXT2_ET_UNSUPP_FEATURE;
 126         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
 127                 return EXT2_ET_RO_UNSUPP_FEATURE;
 128
 129         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 130         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 131                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 132                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 133         }
 134
 135         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 136         super->s_mkfs_time = super->s_lastcheck = time(NULL);
 137
 138         super->s_creator_os = CREATOR_OS;
 139
 140         fs->blocksize = EXT2_BLOCK_SIZE(super);
 141         fs->fragsize = EXT2_FRAG_SIZE(super);
 142         frags_per_block = fs->blocksize / fs->fragsize;
 143
 144         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 145         set_field(s_blocks_per_group, fs->blocksize * 8);
 146         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 147                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 148         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 149
 150         super->s_blocks_count = param->s_blocks_count;
 151         super->s_r_blocks_count = param->s_r_blocks_count;
 152         if (super->s_r_blocks_count >= param->s_blocks_count) {
 153                 retval = EXT2_ET_INVALID_ARGUMENT;
 154                 goto cleanup;
 155         }
 156
 157         /*
 158          * If we're creating an external journal device, we don't need
 159          * to bother with the rest.
 160          */
 161         if (super->s_feature_incompat &
 162             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 163                 fs->group_desc_count = 0;
 164                 ext2fs_mark_super_dirty(fs);
 165                 *ret_fs = fs;
 166                 return 0;
 167         }
 168
 169 retry:
 170         fs->group_desc_count = (super->s_blocks_count -
 171                                 super->s_first_data_block +
 172                                 EXT2_BLOCKS_PER_GROUP(super) - 1)
 173                 / EXT2_BLOCKS_PER_GROUP(super);
 174         if (fs->group_desc_count == 0)
 175                 return EXT2_ET_TOOSMALL;
 176         fs->desc_blocks = (fs->group_desc_count +
 177                            EXT2_DESC_PER_BLOCK(super) - 1)
 178                 / EXT2_DESC_PER_BLOCK(super);
 179
 180         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 181         set_field(s_inodes_count, super->s_blocks_count / i);
 182
 183         /*
 184          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 185          * that we have enough inodes for the filesystem(!)
 186          */
 187         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 188                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 189
 190         /*
 191          * There should be at least as many inodes as the user
 192          * requested.  Figure out how many inodes per group that
 193          * should be.  But make sure that we don't allocate more than
 194          * one bitmap's worth of inodes each group.
 195          */
 196         ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
 197                 fs->group_desc_count;
 198         if (ipg > fs->blocksize * 8) {
 199                 if (super->s_blocks_per_group >= 256) {
 200                         /* Try again with slightly different parameters */
 201                         super->s_blocks_per_group -= 8;
 202                         super->s_blocks_count = param->s_blocks_count;
 203                         super->s_frags_per_group = super->s_blocks_per_group *
 204                                 frags_per_block;
 205                         goto retry;
 206                 } else
 207                         return EXT2_ET_TOO_MANY_INODES;
 208         }
 209
 210         if (ipg > EXT2_MAX_INODES_PER_GROUP(super))
 211                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 212
 213         super->s_inodes_per_group = ipg;
 214         if (super->s_inodes_count > ipg * fs->group_desc_count)
 215                 super->s_inodes_count = ipg * fs->group_desc_count;
 216
 217         /*
 218          * Make sure the number of inodes per group completely fills
 219          * the inode table blocks in the descriptor.  If not, add some
 220          * additional inodes/group.  Waste not, want not...
 221          */
 222         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 223                                         EXT2_INODE_SIZE(super)) +
 224                                        EXT2_BLOCK_SIZE(super) - 1) /
 225                                       EXT2_BLOCK_SIZE(super));
 226         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 227                                       EXT2_BLOCK_SIZE(super)) /
 228                                      EXT2_INODE_SIZE(super));
 229         /*
 230          * Finally, make sure the number of inodes per group is a
 231          * multiple of 8.  This is needed to simplify the bitmap
 232          * splicing code.
 233          */
 234         super->s_inodes_per_group &= ~7;
 235         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 236                                         EXT2_INODE_SIZE(super)) +
 237                                        EXT2_BLOCK_SIZE(super) - 1) /
 238                                       EXT2_BLOCK_SIZE(super));
 239
 240         /*
 241          * adjust inode count to reflect the adjusted inodes_per_group
 242          */
 243         super->s_inodes_count = super->s_inodes_per_group *
 244                 fs->group_desc_count;
 245         super->s_free_inodes_count = super->s_inodes_count;
 246
 247         /*
 248          * Overhead is the number of bookkeeping blocks per group.  It
 249          * includes the superblock backup, the group descriptor
 250          * backups, the inode bitmap, the block bitmap, and the inode
 251          * table.
 252          *
 253          * XXX Not all block groups need the descriptor blocks, but
 254          * being clever is tricky...
 255          */
 256         overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group);
 257
 258         /* This can only happen if the user requested too many inodes */
 259         if (overhead > super->s_blocks_per_group)
 260                 return EXT2_ET_TOO_MANY_INODES;
 261
 262         /*
 263          * See if the last group is big enough to support the
 264          * necessary data structures.  If not, we need to get rid of
 265          * it.
 266          */
 267         rem = (int) ((super->s_blocks_count - super->s_first_data_block) %
 268                      super->s_blocks_per_group);
 269         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 270                 return EXT2_ET_TOOSMALL;
 271         if (rem && (rem < overhead+50)) {
 272                 super->s_blocks_count -= rem;
 273                 goto retry;
 274         }
 275
 276         /*
 277          * At this point we know how big the filesystem will be.  So
 278          * we can do any and all allocations that depend on the block
 279          * count.
 280          */
 281
 282         retval = ext2fs_get_mem(strlen(fs->device_name) + 80,
 283                                 (void **) &buf);
 284         if (retval)
 285                 goto cleanup;
 286
 287         sprintf(buf, "block bitmap for %s", fs->device_name);
 288         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 289         if (retval)
 290                 goto cleanup;
 291
 292         sprintf(buf, "inode bitmap for %s", fs->device_name);
 293         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 294         if (retval)
 295                 goto cleanup;
 296
 297         ext2fs_free_mem((void **) &buf);
 298
 299         retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
 300                                 (void **) &fs->group_desc);
 301         if (retval)
 302                 goto cleanup;
 303
 304         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 305
 306         /*
 307          * Reserve the superblock and group descriptors for each
 308          * group, and fill in the correct group statistics for group.
 309          * Note that although the block bitmap, inode bitmap, and
 310          * inode table have not been allocated (and in fact won't be
 311          * by this routine), they are accounted for nevertheless.
 312          */
 313         group_block = super->s_first_data_block;
 314         super->s_free_blocks_count = 0;
 315         if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
 316                 old_desc_blocks = fs->super->s_first_meta_bg;
 317         else
 318                 old_desc_blocks = fs->desc_blocks;
 319         for (i = 0; i < fs->group_desc_count; i++) {
 320                 if (i == fs->group_desc_count-1) {
 321                         numblocks = (fs->super->s_blocks_count -
 322                                      fs->super->s_first_data_block) %
 323                                              fs->super->s_blocks_per_group;
 324                         if (!numblocks)
 325                                 numblocks = fs->super->s_blocks_per_group;
 326                 } else
 327                         numblocks = fs->super->s_blocks_per_group;
 328
 329                 has_super = ext2fs_bg_has_super(fs, i);
 330
 331                 if (has_super) {
 332                         ext2fs_mark_block_bitmap(fs->block_map, group_block);
 333                         numblocks--;
 334                 }
 335                 meta_bg_size = (fs->blocksize /
 336                                 sizeof (struct ext2_group_desc));
 337                 meta_bg = i / meta_bg_size;
 338
 339                 if (!(fs->super->s_feature_incompat &
 340                       EXT2_FEATURE_INCOMPAT_META_BG) ||
 341                     (meta_bg < fs->super->s_first_meta_bg)) {
 342                         if (has_super) {
 343                                 for (j=0; j < old_desc_blocks; j++)
 344                                         ext2fs_mark_block_bitmap(fs->block_map,
 345                                                          group_block + j + 1);
 346                                 numblocks -= old_desc_blocks;
 347                         }
 348                 } else {
 349                         if (has_super)
 350                                 has_super = 1;
 351                         if (((i % meta_bg_size) == 0) ||
 352                             ((i % meta_bg_size) == 1) ||
 353                             ((i % meta_bg_size) == (meta_bg_size-1))) {
 354                                 ext2fs_mark_block_bitmap(fs->block_map,
 355                                          group_block + has_super);
 356                                 numblocks--;
 357                         }
 358                 }
 359
 360                 numblocks -= 2 + fs->inode_blocks_per_group;
 361
 362                 super->s_free_blocks_count += numblocks;
 363                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 364                 fs->group_desc[i].bg_free_inodes_count =
 365                         fs->super->s_inodes_per_group;
 366                 fs->group_desc[i].bg_used_dirs_count = 0;
 367
 368                 group_block += super->s_blocks_per_group;
 369         }
 370
 371         ext2fs_mark_super_dirty(fs);
 372         ext2fs_mark_bb_dirty(fs);
 373         ext2fs_mark_ib_dirty(fs);
 374
 375         io_channel_set_blksize(fs->io, fs->blocksize);
 376
 377         *ret_fs = fs;
 378         return 0;
 379 cleanup:
 380         ext2fs_free(fs);
 381         return retval;
 382 }