git.maemo.org Git - busybox4maemo/blob - e2fsprogs/old_e2fsprogs/ext2fs/initialize.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * initialize.c --- initialize a filesystem handle given superblock
   4  *      parameters.  Used by mke2fs when initializing a filesystem.
   5  *
   6  * Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
   7  *
   8  * %Begin-Header%
   9  * This file may be redistributed under the terms of the GNU Public
  10  * License.
  11  * %End-Header%
  12  */
  13
  14 #include <stdio.h>
  15 #include <string.h>
  16 #if HAVE_UNISTD_H
  17 #include <unistd.h>
  18 #endif
  19 #include <fcntl.h>
  20 #include <time.h>
  21 #if HAVE_SYS_STAT_H
  22 #include <sys/stat.h>
  23 #endif
  24 #if HAVE_SYS_TYPES_H
  25 #include <sys/types.h>
  26 #endif
  27
  28 #include "ext2_fs.h"
  29 #include "ext2fs.h"
  30
  31 #if defined(__linux__)    &&    defined(EXT2_OS_LINUX)
  32 #define CREATOR_OS EXT2_OS_LINUX
  33 #else
  34 #if defined(__GNU__)     &&     defined(EXT2_OS_HURD)
  35 #define CREATOR_OS EXT2_OS_HURD
  36 #else
  37 #if defined(__FreeBSD__) &&     defined(EXT2_OS_FREEBSD)
  38 #define CREATOR_OS EXT2_OS_FREEBSD
  39 #else
  40 #if defined(LITES)         &&   defined(EXT2_OS_LITES)
  41 #define CREATOR_OS EXT2_OS_LITES
  42 #else
  43 #define CREATOR_OS EXT2_OS_LINUX /* by default */
  44 #endif /* defined(LITES) && defined(EXT2_OS_LITES) */
  45 #endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
  46 #endif /* defined(__GNU__)     && defined(EXT2_OS_HURD) */
  47 #endif /* defined(__linux__)   && defined(EXT2_OS_LINUX) */
  48
  49 /*
  50  * Note we override the kernel include file's idea of what the default
  51  * check interval (never) should be.  It's a good idea to check at
  52  * least *occasionally*, specially since servers will never rarely get
  53  * to reboot, since Linux is so robust these days.  :-)
  54  *
  55  * 180 days (six months) seems like a good value.
  56  */
  57 #ifdef EXT2_DFL_CHECKINTERVAL
  58 #undef EXT2_DFL_CHECKINTERVAL
  59 #endif
  60 #define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
  61
  62 /*
  63  * Calculate the number of GDT blocks to reserve for online filesystem growth.
  64  * The absolute maximum number of GDT blocks we can reserve is determined by
  65  * the number of block pointers that can fit into a single block.
  66  */
  67 static int calc_reserved_gdt_blocks(ext2_filsys fs)
  68 {
  69         struct ext2_super_block *sb = fs->super;
  70         unsigned long bpg = sb->s_blocks_per_group;
  71         unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc);
  72         unsigned long max_blocks = 0xffffffff;
  73         unsigned long rsv_groups;
  74         int rsv_gdb;
  75
  76         /* We set it at 1024x the current filesystem size, or
  77          * the upper block count limit (2^32), whichever is lower.
  78          */
  79         if (sb->s_blocks_count < max_blocks / 1024)
  80                 max_blocks = sb->s_blocks_count * 1024;
  81         rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg;
  82         rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks;
  83         if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
  84                 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
  85 #ifdef RES_GDT_DEBUG
  86         printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %lu\n",
  87                max_blocks, rsv_groups, rsv_gdb);
  88 #endif
  89
  90         return rsv_gdb;
  91 }
  92
  93 errcode_t ext2fs_initialize(const char *name, int flags,
  94                             struct ext2_super_block *param,
  95                             io_manager manager, ext2_filsys *ret_fs)
  96 {
  97         ext2_filsys     fs;
  98         errcode_t       retval;
  99         struct ext2_super_block *super;
 100         int             frags_per_block;
 101         unsigned int    rem;
 102         unsigned int    overhead = 0;
 103         blk_t           group_block;
 104         unsigned int    ipg;
 105         dgrp_t          i;
 106         blk_t           numblocks;
 107         int             rsv_gdt;
 108         char            *buf;
 109
 110         if (!param || !param->s_blocks_count)
 111                 return EXT2_ET_INVALID_ARGUMENT;
 112
 113         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 114         if (retval)
 115                 return retval;
 116
 117         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 118         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 119         fs->flags = flags | EXT2_FLAG_RW;
 120         fs->umask = 022;
 121 #ifdef WORDS_BIGENDIAN
 122         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 123 #endif
 124         retval = manager->open(name, IO_FLAG_RW, &fs->io);
 125         if (retval)
 126                 goto cleanup;
 127         fs->image_io = fs->io;
 128         fs->io->app_data = fs;
 129         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 130         if (retval)
 131                 goto cleanup;
 132
 133         strcpy(fs->device_name, name);
 134         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 135         if (retval)
 136                 goto cleanup;
 137         fs->super = super;
 138
 139         memset(super, 0, SUPERBLOCK_SIZE);
 140
 141 #define set_field(field, default) (super->field = param->field ? \
 142                                    param->field : (default))
 143
 144         super->s_magic = EXT2_SUPER_MAGIC;
 145         super->s_state = EXT2_VALID_FS;
 146
 147         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 148         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 149         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 150         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 151         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 152         set_field(s_feature_compat, 0);
 153         set_field(s_feature_incompat, 0);
 154         set_field(s_feature_ro_compat, 0);
 155         set_field(s_first_meta_bg, 0);
 156         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 157                 retval = EXT2_ET_UNSUPP_FEATURE;
 158                 goto cleanup;
 159         }
 160         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
 161                 retval = EXT2_ET_RO_UNSUPP_FEATURE;
 162                 goto cleanup;
 163         }
 164
 165         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 166         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 167                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 168                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 169         }
 170
 171         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 172         super->s_mkfs_time = super->s_lastcheck = time(NULL);
 173
 174         super->s_creator_os = CREATOR_OS;
 175
 176         fs->blocksize = EXT2_BLOCK_SIZE(super);
 177         fs->fragsize = EXT2_FRAG_SIZE(super);
 178         frags_per_block = fs->blocksize / fs->fragsize;
 179
 180         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 181         set_field(s_blocks_per_group, fs->blocksize * 8);
 182         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 183                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 184         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 185
 186         super->s_blocks_count = param->s_blocks_count;
 187         super->s_r_blocks_count = param->s_r_blocks_count;
 188         if (super->s_r_blocks_count >= param->s_blocks_count) {
 189                 retval = EXT2_ET_INVALID_ARGUMENT;
 190                 goto cleanup;
 191         }
 192
 193         /*
 194          * If we're creating an external journal device, we don't need
 195          * to bother with the rest.
 196          */
 197         if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 198                 fs->group_desc_count = 0;
 199                 ext2fs_mark_super_dirty(fs);
 200                 *ret_fs = fs;
 201                 return 0;
 202         }
 203
 204 retry:
 205         fs->group_desc_count = (super->s_blocks_count -
 206                                 super->s_first_data_block +
 207                                 EXT2_BLOCKS_PER_GROUP(super) - 1)
 208                 / EXT2_BLOCKS_PER_GROUP(super);
 209         if (fs->group_desc_count == 0) {
 210                 retval = EXT2_ET_TOOSMALL;
 211                 goto cleanup;
 212         }
 213         fs->desc_blocks = (fs->group_desc_count +
 214                            EXT2_DESC_PER_BLOCK(super) - 1)
 215                 / EXT2_DESC_PER_BLOCK(super);
 216
 217         i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
 218         set_field(s_inodes_count, super->s_blocks_count / i);
 219
 220         /*
 221          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 222          * that we have enough inodes for the filesystem(!)
 223          */
 224         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 225                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 226
 227         /*
 228          * There should be at least as many inodes as the user
 229          * requested.  Figure out how many inodes per group that
 230          * should be.  But make sure that we don't allocate more than
 231          * one bitmap's worth of inodes each group.
 232          */
 233         ipg = (super->s_inodes_count + fs->group_desc_count - 1) /
 234                 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_frags_per_group = super->s_blocks_per_group *
 241                                 frags_per_block;
 242                         goto retry;
 243                 } else
 244                         return EXT2_ET_TOO_MANY_INODES;
 245         }
 246
 247         if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
 248                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 249
 250         super->s_inodes_per_group = ipg;
 251         if (super->s_inodes_count > ipg * fs->group_desc_count)
 252                 super->s_inodes_count = ipg * fs->group_desc_count;
 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         super->s_inodes_count = super->s_inodes_per_group *
 281                 fs->group_desc_count;
 282         super->s_free_inodes_count = super->s_inodes_count;
 283
 284         /*
 285          * check the number of reserved group descriptor table blocks
 286          */
 287         if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
 288                 rsv_gdt = calc_reserved_gdt_blocks(fs);
 289         else
 290                 rsv_gdt = 0;
 291         set_field(s_reserved_gdt_blocks, rsv_gdt);
 292         if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
 293                 retval = EXT2_ET_RES_GDT_BLOCKS;
 294                 goto cleanup;
 295         }
 296
 297         /*
 298          * Overhead is the number of bookkeeping blocks per group.  It
 299          * includes the superblock backup, the group descriptor
 300          * backups, the inode bitmap, the block bitmap, and the inode
 301          * table.
 302          */
 303
 304         overhead = (int) (2 + fs->inode_blocks_per_group);
 305
 306         if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
 307                 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
 308
 309         /* This can only happen if the user requested too many inodes */
 310         if (overhead > super->s_blocks_per_group)
 311                 return EXT2_ET_TOO_MANY_INODES;
 312
 313         /*
 314          * See if the last group is big enough to support the
 315          * necessary data structures.  If not, we need to get rid of
 316          * it.
 317          */
 318         rem = ((super->s_blocks_count - super->s_first_data_block) %
 319                super->s_blocks_per_group);
 320         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 321                 return EXT2_ET_TOOSMALL;
 322         if (rem && (rem < overhead+50)) {
 323                 super->s_blocks_count -= rem;
 324                 goto retry;
 325         }
 326
 327         /*
 328          * At this point we know how big the filesystem will be.  So
 329          * we can do any and all allocations that depend on the block
 330          * count.
 331          */
 332
 333         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 334         if (retval)
 335                 goto cleanup;
 336
 337         sprintf(buf, "block bitmap for %s", fs->device_name);
 338         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 339         if (retval)
 340                 goto cleanup;
 341
 342         sprintf(buf, "inode bitmap for %s", fs->device_name);
 343         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 344         if (retval)
 345                 goto cleanup;
 346
 347         ext2fs_free_mem(&buf);
 348
 349         retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
 350                                 &fs->group_desc);
 351         if (retval)
 352                 goto cleanup;
 353
 354         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 355
 356         /*
 357          * Reserve the superblock and group descriptors for each
 358          * group, and fill in the correct group statistics for group.
 359          * Note that although the block bitmap, inode bitmap, and
 360          * inode table have not been allocated (and in fact won't be
 361          * by this routine), they are accounted for nevertheless.
 362          */
 363         group_block = super->s_first_data_block;
 364         super->s_free_blocks_count = 0;
 365         for (i = 0; i < fs->group_desc_count; i++) {
 366                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 367
 368                 super->s_free_blocks_count += numblocks;
 369                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 370                 fs->group_desc[i].bg_free_inodes_count =
 371                         fs->super->s_inodes_per_group;
 372                 fs->group_desc[i].bg_used_dirs_count = 0;
 373
 374                 group_block += super->s_blocks_per_group;
 375         }
 376
 377         ext2fs_mark_super_dirty(fs);
 378         ext2fs_mark_bb_dirty(fs);
 379         ext2fs_mark_ib_dirty(fs);
 380
 381         io_channel_set_blksize(fs->io, fs->blocksize);
 382
 383         *ret_fs = fs;
 384         return 0;
 385 cleanup:
 386         ext2fs_free(fs);
 387         return retval;
 388 }