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 #elif defined(__GNU__)     &&   defined(EXT2_OS_HURD)
  33 #define CREATOR_OS EXT2_OS_HURD
  34 #elif defined(__FreeBSD__) &&   defined(EXT2_OS_FREEBSD)
  35 #define CREATOR_OS EXT2_OS_FREEBSD
  36 #elif defined(LITES)       &&   defined(EXT2_OS_LITES)
  37 #define CREATOR_OS EXT2_OS_LITES
  38 #else
  39 #define CREATOR_OS EXT2_OS_LINUX /* by default */
  40 #endif
  41
  42 /*
  43  * Note we override the kernel include file's idea of what the default
  44  * check interval (never) should be.  It's a good idea to check at
  45  * least *occasionally*, specially since servers will never rarely get
  46  * to reboot, since Linux is so robust these days.  :-)
  47  *
  48  * 180 days (six months) seems like a good value.
  49  */
  50 #ifdef EXT2_DFL_CHECKINTERVAL
  51 #undef EXT2_DFL_CHECKINTERVAL
  52 #endif
  53 #define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
  54
  55 errcode_t ext2fs_initialize(const char *name, int flags,
  56                             struct ext2_super_block *param,
  57                             io_manager manager, ext2_filsys *ret_fs)
  58 {
  59         ext2_filsys     fs;
  60         errcode_t       retval;
  61         struct ext2_super_block *super;
  62         int             frags_per_block;
  63         int             rem;
  64         int             overhead = 0;
  65         blk_t           group_block;
  66         int             i, j;
  67         blk_t           numblocks;
  68         char            *buf;
  69
  70         if (!param || !param->s_blocks_count)
  71                 return EXT2_ET_INVALID_ARGUMENT;
  72
  73         retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys),
  74                                 (void **) &fs);
  75         if (retval)
  76                 return retval;
  77
  78         memset(fs, 0, sizeof(struct struct_ext2_filsys));
  79         fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
  80         fs->flags = flags | EXT2_FLAG_RW | ext2fs_native_flag();
  81         retval = manager->open(name, IO_FLAG_RW, &fs->io);
  82         if (retval)
  83                 goto cleanup;
  84         fs->io->app_data = fs;
  85         retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name);
  86         if (retval)
  87                 goto cleanup;
  88
  89         strcpy(fs->device_name, name);
  90         retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super);
  91         if (retval)
  92                 goto cleanup;
  93         fs->super = super;
  94
  95         memset(super, 0, SUPERBLOCK_SIZE);
  96
  97 #define set_field(field, default) (super->field = param->field ? \
  98                                    param->field : (default))
  99
 100         super->s_magic = EXT2_SUPER_MAGIC;
 101         super->s_state = EXT2_VALID_FS;
 102
 103         set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
 104         set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
 105         set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
 106         set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
 107         set_field(s_errors, EXT2_ERRORS_DEFAULT);
 108         set_field(s_feature_compat, 0);
 109         set_field(s_feature_incompat, 0);
 110         set_field(s_feature_ro_compat, 0);
 111         if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP)
 112                 return EXT2_ET_UNSUPP_FEATURE;
 113         if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)
 114                 return EXT2_ET_RO_UNSUPP_FEATURE;
 115
 116         set_field(s_rev_level, EXT2_GOOD_OLD_REV);
 117         if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
 118                 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
 119                 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
 120         }
 121
 122         set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
 123         super->s_lastcheck = time(NULL);
 124
 125         super->s_creator_os = CREATOR_OS;
 126
 127         fs->blocksize = EXT2_BLOCK_SIZE(super);
 128         fs->fragsize = EXT2_FRAG_SIZE(super);
 129         frags_per_block = fs->blocksize / fs->fragsize;
 130
 131         /* default: (fs->blocksize*8) blocks/group */
 132         set_field(s_blocks_per_group, fs->blocksize*8);
 133         super->s_frags_per_group = super->s_blocks_per_group * frags_per_block;
 134
 135         super->s_blocks_count = param->s_blocks_count;
 136         super->s_r_blocks_count = param->s_r_blocks_count;
 137         if (super->s_r_blocks_count >= param->s_blocks_count) {
 138                 retval = EXT2_ET_INVALID_ARGUMENT;
 139                 goto cleanup;
 140         }
 141
 142         /*
 143          * If we're creating an external journal device, we don't need
 144          * to bother with the rest.
 145          */
 146         if (super->s_feature_incompat &
 147             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
 148                 fs->group_desc_count = 0;
 149                 ext2fs_mark_super_dirty(fs);
 150                 *ret_fs = fs;
 151                 return 0;
 152         }
 153
 154 retry:
 155         fs->group_desc_count = (super->s_blocks_count -
 156                                 super->s_first_data_block +
 157                                 EXT2_BLOCKS_PER_GROUP(super) - 1)
 158                 / EXT2_BLOCKS_PER_GROUP(super);
 159         if (fs->group_desc_count == 0)
 160                 return EXT2_ET_TOOSMALL;
 161         fs->desc_blocks = (fs->group_desc_count +
 162                            EXT2_DESC_PER_BLOCK(super) - 1)
 163                 / EXT2_DESC_PER_BLOCK(super);
 164
 165         /* n.b., fs->blocksize is <= 4096 */
 166         set_field(s_inodes_count, super->s_blocks_count/(4096/fs->blocksize));
 167
 168         /*
 169          * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
 170          * that we have enough inodes for the filesystem(!)
 171          */
 172         if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
 173                 super->s_inodes_count = EXT2_FIRST_INODE(super)+1;
 174
 175         /*
 176          * There should be at least as many inodes as the user
 177          * requested.  Figure out how many inodes per group that
 178          * should be.  But make sure that we don't allocate more than
 179          * one bitmap's worth of inodes
 180          */
 181         super->s_inodes_per_group = (super->s_inodes_count +
 182                                      fs->group_desc_count - 1) /
 183                                              fs->group_desc_count;
 184         if (super->s_inodes_per_group > fs->blocksize*8)
 185                 super->s_inodes_per_group = fs->blocksize*8;
 186
 187         /*
 188          * Make sure the number of inodes per group completely fills
 189          * the inode table blocks in the descriptor.  If not, add some
 190          * additional inodes/group.  Waste not, want not...
 191          */
 192         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 193                                         EXT2_INODE_SIZE(super)) +
 194                                        EXT2_BLOCK_SIZE(super) - 1) /
 195                                       EXT2_BLOCK_SIZE(super));
 196         super->s_inodes_per_group = ((fs->inode_blocks_per_group *
 197                                       EXT2_BLOCK_SIZE(super)) /
 198                                      EXT2_INODE_SIZE(super));
 199         /*
 200          * Finally, make sure the number of inodes per group is a
 201          * multiple of 8.  This is needed to simplify the bitmap
 202          * splicing code.
 203          */
 204         super->s_inodes_per_group &= ~7;
 205         fs->inode_blocks_per_group = (((super->s_inodes_per_group *
 206                                         EXT2_INODE_SIZE(super)) +
 207                                        EXT2_BLOCK_SIZE(super) - 1) /
 208                                       EXT2_BLOCK_SIZE(super));
 209
 210         /*
 211          * adjust inode count to reflect the adjusted inodes_per_group
 212          */
 213         super->s_inodes_count = super->s_inodes_per_group *
 214                 fs->group_desc_count;
 215         super->s_free_inodes_count = super->s_inodes_count;
 216
 217         /*
 218          * Overhead is the number of bookkeeping blocks per group.  It
 219          * includes the superblock backup, the group descriptor
 220          * backups, the inode bitmap, the block bitmap, and the inode
 221          * table.
 222          *
 223          * XXX Not all block groups need the descriptor blocks, but
 224          * being clever is tricky...
 225          */
 226         overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group);
 227
 228         /*
 229          * See if the last group is big enough to support the
 230          * necessary data structures.  If not, we need to get rid of
 231          * it.
 232          */
 233         rem = (int) ((super->s_blocks_count - super->s_first_data_block) %
 234                      super->s_blocks_per_group);
 235         if ((fs->group_desc_count == 1) && rem && (rem < overhead))
 236                 return EXT2_ET_TOOSMALL;
 237         if (rem && (rem < overhead+50)) {
 238                 super->s_blocks_count -= rem;
 239                 goto retry;
 240         }
 241
 242         /*
 243          * At this point we know how big the filesystem will be.  So
 244          * we can do any and all allocations that depend on the block
 245          * count.
 246          */
 247
 248         retval = ext2fs_get_mem(strlen(fs->device_name) + 80,
 249                                 (void **) &buf);
 250         if (retval)
 251                 goto cleanup;
 252
 253         sprintf(buf, "block bitmap for %s", fs->device_name);
 254         retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
 255         if (retval)
 256                 goto cleanup;
 257
 258         sprintf(buf, "inode bitmap for %s", fs->device_name);
 259         retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
 260         if (retval)
 261                 goto cleanup;
 262
 263         ext2fs_free_mem((void **) &buf);
 264
 265         retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize,
 266                                 (void **) &fs->group_desc);
 267         if (retval)
 268                 goto cleanup;
 269
 270         memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);
 271
 272         /*
 273          * Reserve the superblock and group descriptors for each
 274          * group, and fill in the correct group statistics for group.
 275          * Note that although the block bitmap, inode bitmap, and
 276          * inode table have not been allocated (and in fact won't be
 277          * by this routine), they are accounted for nevertheless.
 278          */
 279         group_block = super->s_first_data_block;
 280         super->s_free_blocks_count = 0;
 281         for (i = 0; i < fs->group_desc_count; i++) {
 282                 if (i == fs->group_desc_count-1) {
 283                         numblocks = (fs->super->s_blocks_count -
 284                                      fs->super->s_first_data_block) %
 285                                              fs->super->s_blocks_per_group;
 286                         if (!numblocks)
 287                                 numblocks = fs->super->s_blocks_per_group;
 288                 } else
 289                         numblocks = fs->super->s_blocks_per_group;
 290
 291                 if (ext2fs_bg_has_super(fs, i)) {
 292                         for (j=0; j < fs->desc_blocks+1; j++)
 293                                 ext2fs_mark_block_bitmap(fs->block_map,
 294                                                          group_block + j);
 295                         numblocks -= 1 + fs->desc_blocks;
 296                 }
 297
 298                 numblocks -= 2 + fs->inode_blocks_per_group;
 299
 300                 super->s_free_blocks_count += numblocks;
 301                 fs->group_desc[i].bg_free_blocks_count = numblocks;
 302                 fs->group_desc[i].bg_free_inodes_count =
 303                         fs->super->s_inodes_per_group;
 304                 fs->group_desc[i].bg_used_dirs_count = 0;
 305
 306                 group_block += super->s_blocks_per_group;
 307         }
 308
 309         ext2fs_mark_super_dirty(fs);
 310         ext2fs_mark_bb_dirty(fs);
 311         ext2fs_mark_ib_dirty(fs);
 312
 313         io_channel_set_blksize(fs->io, fs->blocksize);
 314
 315         *ret_fs = fs;
 316         return 0;
 317 cleanup:
 318         ext2fs_free(fs);
 319         return retval;
 320 }
 321
 322
 323