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
  77         if (!param || !param->s_blocks_count)
  78                 return EXT2_ET_INVALID_ARGUMENT;
  79
  80         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
  81         if (retval)
  82                 return retval;
  83
  84         memset(fs, 0, sizeof(struct struct_ext2_filsys));
  85         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
  86         fs->flags = flags | EXT2_FLAG_RW;
  87         fs->umask = 022;
  88 #ifdef WORDS_BIGENDIAN
  89         fs->flags |= EXT2_FLAG_SWAP_BYTES;
  90 #endif
  91         retval = manager->open(name, IO_FLAG_RW, &fs->io);
  92         if (retval)
  93                 goto cleanup;
  94         fs->io->app_data = fs;
  95         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
  96         if (retval)
  97                 goto cleanup;
  98
  99         strcpy(fs->device_name, name);
 100         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 101         if (retval)
 102                 goto cleanup;
 103         fs->super = super;
 104
 105         memset(super, 0, SUPERBLOCK_SIZE);
 106
 107 #define set_field(field, default) (super->field = param->field ? \
 108                                    param->field : (default))
 109
 110         super->s_magic = EXT2_SUPER_MAGIC;
 111         super->s_state = EXT2_VALID_FS;
 112
 113         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 114         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 115         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 116         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 117         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 118         set_field(s_feature_compat, 0);
 119         set_field(s_feature_incompat, 0);
 120         set_field(s_feature_ro_compat, 0);
 121         set_field(s_first_meta_bg, 0);
 122         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
 123                 return EXT2_ET_UNSUPP_FEATURE;
 124         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
 125                 return EXT2_ET_RO_UNSUPP_FEATURE;
 126
 127         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 128         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 129                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 130                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 131         }
 132
 133         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 134         super->s_mkfs_time = super->s_lastcheck = time(NULL);
 135
 136         super->s_creator_os = CREATOR_OS;
 137
 138         fs->blocksize = EXT2_BLOCK_SIZE(super);
 139         fs->fragsize = EXT2_FRAG_SIZE(super);
 140         frags_per_block = fs->blocksize / fs->fragsize;
 141
 142         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 143         set_field(s_blocks_per_group, fs->blocksize * 8);
 144         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 145                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 146         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 147
 148         super->s_blocks_count = param->s_blocks_count;
 149         super->s_r_blocks_count = param->s_r_blocks_count;
 150         if (super->s_r_blocks_count >= param->s_blocks_count) {
 151                 retval = EXT2_ET_INVALID_ARGUMENT;
 152                 goto cleanup;
 153         }
 154
 155         /*
 156          * If we're creating an external journal device, we don't need
 157          * to bother with the rest.
 158          */
 159         if (super->s_feature_incompat &
 160             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 161                 fs->group_desc_count = 0;
 162                 ext2fs_mark_super_dirty(fs);
 163                 *ret_fs = fs;
 164                 return 0;
 165         }
 166
 167 retry:
 168         fs->group_desc_count = (super->s_blocks_count -
 169                                 super->s_first_data_block +
 170                                 EXT2_BLOCKS_PER_GROUP(super) - 1)
 171                 / EXT2_BLOCKS_PER_GROUP(super);
 172         if (fs->group_desc_count == 0)
 173                 return EXT2_ET_TOOSMALL;
 174         fs->desc_blocks = (fs->group_desc_count +
 175                            EXT2_DESC_PER_BLOCK(super) - 1)
 176                 / EXT2_DESC_PER_BLOCK(super);
 177
 178         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 179         set_field(s_inodes_count, super->s_blocks_count / i);
 180
 181         /*
 182          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 183          * that we have enough inodes for the filesystem(!)
 184          */
 185         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 186                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 187
 188         /*
 189          * There should be at least as many inodes as the user
 190          * requested.  Figure out how many inodes per group that
 191          * should be.  But make sure that we don't allocate more than
 192          * one bitmap's worth of inodes each group.
 193          */
 194         ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
 195                 fs->group_desc_count;
 196         if (ipg > fs->blocksize * 8) {
 197                 if (super->s_blocks_per_group >= 256) {
 198                         /* Try again with slightly different parameters */
 199                         super->s_blocks_per_group -= 8;
 200                         super->s_blocks_count = param->s_blocks_count;
 201                         super->s_frags_per_group = super->s_blocks_per_group *
 202                                 frags_per_block;
 203                         goto retry;
 204                 } else
 205                         return EXT2_ET_TOO_MANY_INODES;
 206         }
 207
 208         if (ipg > EXT2_MAX_INODES_PER_GROUP(super))
 209                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 210
 211         super->s_inodes_per_group = ipg;
 212         if (super->s_inodes_count > ipg * fs->group_desc_count)
 213                 super->s_inodes_count = ipg * fs->group_desc_count;
 214
 215         /*
 216          * Make sure the number of inodes per group completely fills
 217          * the inode table blocks in the descriptor.  If not, add some
 218          * additional inodes/group.  Waste not, want not...
 219          */
 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         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 225                                       EXT2_BLOCK_SIZE(super)) /
 226                                      EXT2_INODE_SIZE(super));
 227         /*
 228          * Finally, make sure the number of inodes per group is a
 229          * multiple of 8.  This is needed to simplify the bitmap
 230          * splicing code.
 231          */
 232         super->s_inodes_per_group &= ~7;
 233         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 234                                         EXT2_INODE_SIZE(super)) +
 235                                        EXT2_BLOCK_SIZE(super) - 1) /
 236                                       EXT2_BLOCK_SIZE(super));
 237
 238         /*
 239          * adjust inode count to reflect the adjusted inodes_per_group
 240          */
 241         super->s_inodes_count = super->s_inodes_per_group *
 242                 fs->group_desc_count;
 243         super->s_free_inodes_count = super->s_inodes_count;
 244
 245         /*
 246          * Overhead is the number of bookkeeping blocks per group.  It
 247          * includes the superblock backup, the group descriptor
 248          * backups, the inode bitmap, the block bitmap, and the inode
 249          * table.
 250          *
 251          * XXX Not all block groups need the descriptor blocks, but
 252          * being clever is tricky...
 253          */
 254         overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group);
 255
 256         /* This can only happen if the user requested too many inodes */
 257         if (overhead > super->s_blocks_per_group)
 258                 return EXT2_ET_TOO_MANY_INODES;
 259
 260         /*
 261          * See if the last group is big enough to support the
 262          * necessary data structures.  If not, we need to get rid of
 263          * it.
 264          */
 265         rem = (int) ((super->s_blocks_count - super->s_first_data_block) %
 266                      super->s_blocks_per_group);
 267         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 268                 return EXT2_ET_TOOSMALL;
 269         if (rem && (rem < overhead+50)) {
 270                 super->s_blocks_count -= rem;
 271                 goto retry;
 272         }
 273
 274         /*
 275          * At this point we know how big the filesystem will be.  So
 276          * we can do any and all allocations that depend on the block
 277          * count.
 278          */
 279
 280         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 281         if (retval)
 282                 goto cleanup;
 283
 284         sprintf(buf, "block bitmap for %s", fs->device_name);
 285         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 286         if (retval)
 287                 goto cleanup;
 288
 289         sprintf(buf, "inode bitmap for %s", fs->device_name);
 290         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 291         if (retval)
 292                 goto cleanup;
 293
 294         ext2fs_free_mem(&buf);
 295
 296         retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
 297                                 &fs->group_desc);
 298         if (retval)
 299                 goto cleanup;
 300
 301         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 302
 303         /*
 304          * Reserve the superblock and group descriptors for each
 305          * group, and fill in the correct group statistics for group.
 306          * Note that although the block bitmap, inode bitmap, and
 307          * inode table have not been allocated (and in fact won't be
 308          * by this routine), they are accounted for nevertheless.
 309          */
 310         group_block = super->s_first_data_block;
 311         super->s_free_blocks_count = 0;
 312         for (i = 0; i < fs->group_desc_count; i++) {
 313                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 314
 315                 super->s_free_blocks_count += numblocks;
 316                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 317                 fs->group_desc[i].bg_free_inodes_count =
 318                         fs->super->s_inodes_per_group;
 319                 fs->group_desc[i].bg_used_dirs_count = 0;
 320
 321                 group_block += super->s_blocks_per_group;
 322         }
 323
 324         ext2fs_mark_super_dirty(fs);
 325         ext2fs_mark_bb_dirty(fs);
 326         ext2fs_mark_ib_dirty(fs);
 327
 328         io_channel_set_blksize(fs->io, fs->blocksize);
 329
 330         *ret_fs = fs;
 331         return 0;
 332 cleanup:
 333         ext2fs_free(fs);
 334         return retval;
 335 }