lib/ext2fs/alloc_tables.c

   1 /*
   2  * alloc_tables.c --- Allocate tables for a newly initialized
   3  * filesystem.  Used by mke2fs when initializing a filesystem
   4  *
   5  * Copyright (C) 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 <stdlib.h>
  19 #include <fcntl.h>
  20 #include <time.h>
  21 #include <sys/stat.h>
  22 #include <sys/types.h>
  23 #if HAVE_ERRNO_H
  24 #include <errno.h>
  25 #endif
  26
  27 #include <linux/ext2_fs.h>
  28
  29 #include "ext2fs.h"
  30
  31 errcode_t ext2fs_allocate_group_table(ext2_filsys fs, int group,
  32                                       ext2fs_block_bitmap bmap)
  33 {
  34         errcode_t       retval;
  35         blk_t           group_blk, start_blk, last_blk, new_blk, blk;
  36         int             j;
  37
  38         group_blk = fs->super->s_first_data_block +
  39                 (group * fs->super->s_blocks_per_group);
  40
  41         last_blk = group_blk + fs->super->s_blocks_per_group;
  42         if (last_blk >= fs->super->s_blocks_count)
  43                 last_blk = fs->super->s_blocks_count - 1;
  44
  45         start_blk = group_blk + 3 + fs->desc_blocks;
  46         if (start_blk > last_blk)
  47                 start_blk = group_blk;
  48
  49         if (!bmap)
  50                 bmap = fs->block_map;
  51
  52         /*
  53          * Allocate the inode table
  54          */
  55         if (!fs->group_desc[group].bg_inode_table) {
  56                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
  57                                                 fs->inode_blocks_per_group,
  58                                                 bmap, &new_blk);
  59                 if (retval)
  60                         return retval;
  61                 for (j=0, blk = new_blk;
  62                      j < fs->inode_blocks_per_group;
  63                      j++, blk++)
  64                         ext2fs_mark_block_bitmap(bmap, blk);
  65                 fs->group_desc[group].bg_inode_table = new_blk;
  66         }
  67
  68         /*
  69          * Allocate the block and inode bitmaps, if necessary
  70          */
  71         if (fs->stride) {
  72                 start_blk += fs->inode_blocks_per_group;
  73                 start_blk += ((fs->stride * group) %
  74                               (last_blk - start_blk));
  75                 if (start_blk > last_blk)
  76                         /* should never happen */
  77                         start_blk = group_blk;
  78         } else
  79                 start_blk = group_blk;
  80
  81         if (!fs->group_desc[group].bg_block_bitmap) {
  82                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
  83                                                 1, bmap, &new_blk);
  84                 if (retval)
  85                         return retval;
  86                 ext2fs_mark_block_bitmap(bmap, new_blk);
  87                 fs->group_desc[group].bg_block_bitmap = new_blk;
  88         }
  89
  90         if (!fs->group_desc[group].bg_inode_bitmap) {
  91                 retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
  92                                                 1, bmap, &new_blk);
  93                 if (retval)
  94                         return retval;
  95                 ext2fs_mark_block_bitmap(bmap, new_blk);
  96                 fs->group_desc[group].bg_inode_bitmap = new_blk;
  97         }
  98         return 0;
  99 }
 100
 101
 102
 103 errcode_t ext2fs_allocate_tables(ext2_filsys fs)
 104 {
 105         errcode_t       retval;
 106         int             i;
 107
 108         for (i = 0; i < fs->group_desc_count; i++) {
 109                 retval = ext2fs_allocate_group_table(fs, i, fs->block_map);
 110                 if (retval)
 111                         return retval;
 112         }
 113         return 0;
 114 }
 115