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 #if EXT2_FLAT_INCLUDES
  28 #include "ext2_fs.h"
  29 #else
  30 #include <linux/ext2_fs.h>
  31 #endif
  32
  33 #include "ext2fs.h"
  34
  35 #if  defined(__linux__)    &&   defined(EXT2_OS_LINUX)
  36 #define CREATOR_OS EXT2_OS_LINUX
  37 #elif defined(__gnu__)     &&   defined(EXT2_OS_HURD)
  38 #define CREATOR_OS EXT2_OS_HURD
  39 #elif defined(__FreeBSD__) &&   defined(EXT2_OS_FREEBSD)
  40 #define CREATOR_OS EXT2_OS_FREEBSD
  41 #elif defined(LITES)       &&   defined(EXT2_OS_LITES)
  42 #define CREATOR_OS EXT2_OS_LITES
  43 #else
  44 #define CREATOR_OS EXT2_OS_LINUX /* by default */
  45 #endif
  46
  47 /*
  48  * Note we override the kernel include file's idea of what the default
  49  * check interval (never) should be.  It's a good idea to check at
  50  * least *occasionally*, specially since servers will never rarely get
  51  * to reboot, since Linux is so robust these days.  :-)
  52  *
  53  * 180 days (six months) seems like a good value.
  54  */
  55 #ifdef EXT2_DFL_CHECKINTERVAL
  56 #undef EXT2_DFL_CHECKINTERVAL
  57 #endif
  58 #define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
  59
  60 errcode_t ext2fs_initialize(const char *name, int flags,
  61                             struct ext2_super_block *param,
  62                             io_manager manager, ext2_filsys *ret_fs)
  63 {
  64         ext2_filsys     fs;
  65         errcode_t       retval;
  66         struct ext2_super_block *super;
  67         int             frags_per_block;
  68         int             rem;
  69         int             overhead = 0;
  70         blk_t           group_block;
  71         int             i, j;
  72         blk_t           numblocks;
  73         char            *buf;
  74
  75         if (!param || !param->s_blocks_count)
  76                 return EXT2_ET_INVALID_ARGUMENT;
  77
  78         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys),
  79                                 (void **) &fs);
  80         if (retval)
  81                 return retval;
  82
  83         memset(fs, 0, sizeof(struct struct_ext2_filsys));
  84         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
  85         fs->flags = flags | EXT2_FLAG_RW | ext2fs_native_flag();
  86         retval = manager->open(name, IO_FLAG_RW, &fs->io);
  87         if (retval)
  88                 goto cleanup;
  89         fs->io->app_data = fs;
  90         retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name);
  91         if (retval)
  92                 goto cleanup;
  93
  94         strcpy(fs->device_name, name);
  95         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super);
  96         if (retval)
  97                 goto cleanup;
  98         fs->super = super;
  99
 100         memset(super, 0, SUPERBLOCK_SIZE);
 101
 102 #define set_field(field, default) (super->field = param->field ? \
 103                                    param->field : (default))
 104
 105         super->s_magic = EXT2_SUPER_MAGIC;
 106         super->s_state = EXT2_VALID_FS;
 107
 108         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 109         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 110         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 111         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 112         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 113 #ifdef EXT2_DYNAMIC_REV
 114         set_field(s_feature_compat, 0);
 115         set_field(s_feature_incompat, 0);
 116         set_field(s_feature_ro_compat, 0);
 117         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
 118                 return EXT2_ET_UNSUPP_FEATURE;
 119         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
 120                 return EXT2_ET_RO_UNSUPP_FEATURE;
 121
 122         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 123         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 124                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 125                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 126         }
 127 #endif
 128
 129         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 130         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 */
 139         set_field(s_blocks_per_group, fs->blocksize*8);
 140         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 141
 142         super->s_blocks_count = param->s_blocks_count;
 143         super->s_r_blocks_count = param->s_r_blocks_count;
 144         if (super->s_r_blocks_count >= param->s_blocks_count) {
 145                 retval = EXT2_ET_INVALID_ARGUMENT;
 146                 goto cleanup;
 147         }
 148
 149 retry:
 150         fs->group_desc_count = (super->s_blocks_count -
 151                                 super->s_first_data_block +
 152                                 EXT2_BLOCKS_PER_GROUP(super) - 1)
 153                 / EXT2_BLOCKS_PER_GROUP(super);
 154         if (fs->group_desc_count == 0)
 155                 return EXT2_ET_TOOSMALL;
 156         fs->desc_blocks = (fs->group_desc_count +
 157                            EXT2_DESC_PER_BLOCK(super) - 1)
 158                 / EXT2_DESC_PER_BLOCK(super);
 159
 160         /* n.b., fs->blocksize is <= 4096 */
 161         set_field(s_inodes_count, super->s_blocks_count/(4096/fs->blocksize));
 162
 163         /*
 164          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 165          * that we have enough inodes for the filesystem(!)
 166          */
 167         if (super->s_inodes_count < EXT2_FIRST_INO(super)+1)
 168                 super->s_inodes_count = EXT2_FIRST_INO(super)+1;
 169
 170         /*
 171          * There should be at least as many inodes as the user
 172          * requested.  Figure out how many inodes per group that
 173          * should be.  But make sure that we don't allocate more than
 174          * one bitmap's worth of inodes
 175          */
 176         super->s_inodes_per_group = (super->s_inodes_count +
 177                                      fs->group_desc_count - 1) /
 178                                              fs->group_desc_count;
 179         if (super->s_inodes_per_group > fs->blocksize*8)
 180                 super->s_inodes_per_group = fs->blocksize*8;
 181
 182         /*
 183          * Make sure the number of inodes per group completely fills
 184          * the inode table blocks in the descriptor.  If not, add some
 185          * additional inodes/group.  Waste not, want not...
 186          */
 187         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 188                                         EXT2_INODE_SIZE(super)) +
 189                                        EXT2_BLOCK_SIZE(super) - 1) /
 190                                       EXT2_BLOCK_SIZE(super));
 191         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 192                                       EXT2_BLOCK_SIZE(super)) /
 193                                      EXT2_INODE_SIZE(super));
 194         /*
 195          * Finally, make sure the number of inodes per group is a
 196          * multiple of 8.  This is needed to simplify the bitmap
 197          * splicing code.
 198          */
 199         super->s_inodes_per_group &= ~7;
 200         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 201                                         EXT2_INODE_SIZE(super)) +
 202                                        EXT2_BLOCK_SIZE(super) - 1) /
 203                                       EXT2_BLOCK_SIZE(super));
 204
 205         /*
 206          * adjust inode count to reflect the adjusted inodes_per_group
 207          */
 208         super->s_inodes_count = super->s_inodes_per_group *
 209                 fs->group_desc_count;
 210         super->s_free_inodes_count = super->s_inodes_count;
 211
 212         /*
 213          * Overhead is the number of bookkeeping blocks per group.  It
 214          * includes the superblock backup, the group descriptor
 215          * backups, the inode bitmap, the block bitmap, and the inode
 216          * table.
 217          *
 218          * XXX Not all block groups need the descriptor blocks, but
 219          * being clever is tricky...
 220          */
 221         overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group);
 222
 223         /*
 224          * See if the last group is big enough to support the
 225          * necessary data structures.  If not, we need to get rid of
 226          * it.
 227          */
 228         rem = (int) ((super->s_blocks_count - super->s_first_data_block) %
 229                      super->s_blocks_per_group);
 230         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 231                 return EXT2_ET_TOOSMALL;
 232         if (rem && (rem < overhead+50)) {
 233                 super->s_blocks_count -= rem;
 234                 goto retry;
 235         }
 236
 237         /*
 238          * At this point we know how big the filesystem will be.  So
 239          * we can do any and all allocations that depend on the block
 240          * count.
 241          */
 242
 243         retval = ext2fs_get_mem(strlen(fs->device_name) + 80,
 244                                 (void **) &buf);
 245         if (retval)
 246                 goto cleanup;
 247
 248         sprintf(buf, "block bitmap for %s", fs->device_name);
 249         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 250         if (retval)
 251                 goto cleanup;
 252
 253         sprintf(buf, "inode bitmap for %s", fs->device_name);
 254         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 255         if (retval)
 256                 goto cleanup;
 257
 258         ext2fs_free_mem((void **) &buf);
 259
 260         retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
 261                                 (void **) &fs->group_desc);
 262         if (retval)
 263                 goto cleanup;
 264
 265         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 266
 267         /*
 268          * Reserve the superblock and group descriptors for each
 269          * group, and fill in the correct group statistics for group.
 270          * Note that although the block bitmap, inode bitmap, and
 271          * inode table have not been allocated (and in fact won't be
 272          * by this routine), they are accounted for nevertheless.
 273          */
 274         group_block = super->s_first_data_block;
 275         super->s_free_blocks_count = 0;
 276         for (i = 0; i < fs->group_desc_count; i++) {
 277                 if (i == fs->group_desc_count-1) {
 278                         numblocks = (fs->super->s_blocks_count -
 279                                      fs->super->s_first_data_block) %
 280                                              fs->super->s_blocks_per_group;
 281                         if (!numblocks)
 282                                 numblocks = fs->super->s_blocks_per_group;
 283                 } else
 284                         numblocks = fs->super->s_blocks_per_group;
 285
 286                 if (ext2fs_bg_has_super(fs, i)) {
 287                         for (j=0; j < fs->desc_blocks+1; j++)
 288                                 ext2fs_mark_block_bitmap(fs->block_map,
 289                                                          group_block + j);
 290                         numblocks -= 1 + fs->desc_blocks;
 291                 }
 292
 293                 numblocks -= 2 + fs->inode_blocks_per_group;
 294
 295                 super->s_free_blocks_count += numblocks;
 296                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 297                 fs->group_desc[i].bg_free_inodes_count =
 298                         fs->super->s_inodes_per_group;
 299                 fs->group_desc[i].bg_used_dirs_count = 0;
 300
 301                 group_block += super->s_blocks_per_group;
 302         }
 303
 304         ext2fs_mark_super_dirty(fs);
 305         ext2fs_mark_bb_dirty(fs);
 306         ext2fs_mark_ib_dirty(fs);
 307
 308         io_channel_set_blksize(fs->io, fs->blocksize);
 309
 310         *ret_fs = fs;
 311         return 0;
 312 cleanup:
 313         ext2fs_free(fs);
 314         return retval;
 315 }
 316
 317
 318