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 = fs->blocksize / sizeof(struct ext2_group_desc);
  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             io_flags;
 107         char            *buf;
 108
 109         if (!param || !param->s_blocks_count)
 110                 return EXT2_ET_INVALID_ARGUMENT;
 111
 112         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
 113         if (retval)
 114                 return retval;
 115
 116         memset(fs, 0, sizeof(struct struct_ext2_filsys));
 117         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
 118         fs->flags = flags | EXT2_FLAG_RW;
 119         fs->umask = 022;
 120 #ifdef WORDS_BIGENDIAN
 121         fs->flags |= EXT2_FLAG_SWAP_BYTES;
 122 #endif
 123         io_flags = IO_FLAG_RW;
 124         if (flags & EXT2_FLAG_EXCLUSIVE)
 125                 io_flags |= IO_FLAG_EXCLUSIVE;
 126         retval = manager->open(name, io_flags, &fs->io);
 127         if (retval)
 128                 goto cleanup;
 129         fs->image_io = fs->io;
 130         fs->io->app_data = fs;
 131         retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
 132         if (retval)
 133                 goto cleanup;
 134
 135         strcpy(fs->device_name, name);
 136         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
 137         if (retval)
 138                 goto cleanup;
 139         fs->super = super;
 140
 141         memset(super, 0, SUPERBLOCK_SIZE);
 142
 143 #define set_field(field, default) (super->field = param->field ? \
 144                                    param->field : (default))
 145
 146         super->s_magic = EXT2_SUPER_MAGIC;
 147         super->s_state = EXT2_VALID_FS;
 148
 149         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 150         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 151         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 152         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 153         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 154         set_field(s_feature_compat, 0);
 155         set_field(s_feature_incompat, 0);
 156         set_field(s_feature_ro_compat, 0);
 157         set_field(s_first_meta_bg, 0);
 158         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
 159                 retval = EXT2_ET_UNSUPP_FEATURE;
 160                 goto cleanup;
 161         }
 162         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
 163                 retval = EXT2_ET_RO_UNSUPP_FEATURE;
 164                 goto cleanup;
 165         }
 166
 167         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 168         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 169                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 170                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 171         }
 172
 173         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 174         super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);
 175
 176         super->s_creator_os = CREATOR_OS;
 177
 178         fs->blocksize = EXT2_BLOCK_SIZE(super);
 179         fs->fragsize = EXT2_FRAG_SIZE(super);
 180         frags_per_block = fs->blocksize / fs->fragsize;
 181
 182         /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
 183         set_field(s_blocks_per_group, fs->blocksize * 8);
 184         if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
 185                 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
 186         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 187
 188         super->s_blocks_count = param->s_blocks_count;
 189         super->s_r_blocks_count = param->s_r_blocks_count;
 190         if (super->s_r_blocks_count >= param->s_blocks_count) {
 191                 retval = EXT2_ET_INVALID_ARGUMENT;
 192                 goto cleanup;
 193         }
 194
 195         /*
 196          * If we're creating an external journal device, we don't need
 197          * to bother with the rest.
 198          */
 199         if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 200                 fs->group_desc_count = 0;
 201                 ext2fs_mark_super_dirty(fs);
 202                 *ret_fs = fs;
 203                 return 0;
 204         }
 205
 206 retry:
 207         fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count -
 208                                                super->s_first_data_block,
 209                                                EXT2_BLOCKS_PER_GROUP(super));
 210         if (fs->group_desc_count == 0) {
 211                 retval = EXT2_ET_TOOSMALL;
 212                 goto cleanup;
 213         }
 214         fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
 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 = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
 234         if (ipg > fs->blocksize * 8) {
 235                 if (super->s_blocks_per_group >= 256) {
 236                         /* Try again with slightly different parameters */
 237                         super->s_blocks_per_group -= 8;
 238                         super->s_blocks_count = param->s_blocks_count;
 239                         super->s_frags_per_group = super->s_blocks_per_group *
 240                                 frags_per_block;
 241                         goto retry;
 242                 } else
 243                         return EXT2_ET_TOO_MANY_INODES;
 244         }
 245
 246         if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
 247                 ipg = EXT2_MAX_INODES_PER_GROUP(super);
 248
 249         super->s_inodes_per_group = ipg;
 250         if (super->s_inodes_count > ipg * fs->group_desc_count)
 251                 super->s_inodes_count = ipg * fs->group_desc_count;
 252
 253         /*
 254          * Make sure the number of inodes per group completely fills
 255          * the inode table blocks in the descriptor.  If not, add some
 256          * additional inodes/group.  Waste not, want not...
 257          */
 258         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 259                                         EXT2_INODE_SIZE(super)) +
 260                                        EXT2_BLOCK_SIZE(super) - 1) /
 261                                       EXT2_BLOCK_SIZE(super));
 262         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 263                                       EXT2_BLOCK_SIZE(super)) /
 264                                      EXT2_INODE_SIZE(super));
 265         /*
 266          * Finally, make sure the number of inodes per group is a
 267          * multiple of 8.  This is needed to simplify the bitmap
 268          * splicing code.
 269          */
 270         super->s_inodes_per_group &= ~7;
 271         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 272                                         EXT2_INODE_SIZE(super)) +
 273                                        EXT2_BLOCK_SIZE(super) - 1) /
 274                                       EXT2_BLOCK_SIZE(super));
 275
 276         /*
 277          * adjust inode count to reflect the adjusted inodes_per_group
 278          */
 279         super->s_inodes_count = super->s_inodes_per_group *
 280                 fs->group_desc_count;
 281         super->s_free_inodes_count = super->s_inodes_count;
 282
 283         /*
 284          * check the number of reserved group descriptor table blocks
 285          */
 286         if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
 287                 rsv_gdt = calc_reserved_gdt_blocks(fs);
 288         else
 289                 rsv_gdt = 0;
 290         set_field(s_reserved_gdt_blocks, rsv_gdt);
 291         if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
 292                 retval = EXT2_ET_RES_GDT_BLOCKS;
 293                 goto cleanup;
 294         }
 295
 296         /*
 297          * Overhead is the number of bookkeeping blocks per group.  It
 298          * includes the superblock backup, the group descriptor
 299          * backups, the inode bitmap, the block bitmap, and the inode
 300          * table.
 301          */
 302
 303         overhead = (int) (2 + fs->inode_blocks_per_group);
 304
 305         if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
 306                 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
 307
 308         /* This can only happen if the user requested too many inodes */
 309         if (overhead > super->s_blocks_per_group)
 310                 return EXT2_ET_TOO_MANY_INODES;
 311
 312         /*
 313          * See if the last group is big enough to support the
 314          * necessary data structures.  If not, we need to get rid of
 315          * it.
 316          */
 317         rem = ((super->s_blocks_count - super->s_first_data_block) %
 318                super->s_blocks_per_group);
 319         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 320                 return EXT2_ET_TOOSMALL;
 321         if (rem && (rem < overhead+50)) {
 322                 super->s_blocks_count -= rem;
 323                 goto retry;
 324         }
 325
 326         /*
 327          * At this point we know how big the filesystem will be.  So
 328          * we can do any and all allocations that depend on the block
 329          * count.
 330          */
 331
 332         retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
 333         if (retval)
 334                 goto cleanup;
 335
 336         sprintf(buf, "block bitmap for %s", fs->device_name);
 337         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 338         if (retval)
 339                 goto cleanup;
 340
 341         sprintf(buf, "inode bitmap for %s", fs->device_name);
 342         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 343         if (retval)
 344                 goto cleanup;
 345
 346         ext2fs_free_mem(&buf);
 347
 348         retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
 349                                 &fs->group_desc);
 350         if (retval)
 351                 goto cleanup;
 352
 353         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 354
 355         /*
 356          * Reserve the superblock and group descriptors for each
 357          * group, and fill in the correct group statistics for group.
 358          * Note that although the block bitmap, inode bitmap, and
 359          * inode table have not been allocated (and in fact won't be
 360          * by this routine), they are accounted for nevertheless.
 361          */
 362         super->s_free_blocks_count = 0;
 363         for (i = 0; i < fs->group_desc_count; i++) {
 364                 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
 365
 366                 super->s_free_blocks_count += numblocks;
 367                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 368                 fs->group_desc[i].bg_free_inodes_count =
 369                         fs->super->s_inodes_per_group;
 370                 fs->group_desc[i].bg_used_dirs_count = 0;
 371         }
 372
 373         ext2fs_mark_super_dirty(fs);
 374         ext2fs_mark_bb_dirty(fs);
 375         ext2fs_mark_ib_dirty(fs);
 376
 377         io_channel_set_blksize(fs->io, fs->blocksize);
 378
 379         *ret_fs = fs;
 380         return 0;
 381 cleanup:
 382         ext2fs_free(fs);
 383         return retval;
 384 }