/*

 * alloc_sb.c --- Allocate the superblock and block group descriptors for a

 * newly initialized filesystem.  Used by mke2fs when initializing a filesystem

 *

 * Copyright (C) 1994, 1995, 1996, 2003 Theodore Ts'o.

 *

 * %Begin-Header%

 * This file may be redistributed under the terms of the GNU Library

 * General Public License, version 2.

 * %End-Header%

 */

#include "config.h"

#include <stdio.h>

#include <string.h>

#if HAVE_UNISTD_H

#include <unistd.h>

#endif

#include <fcntl.h>

#include <time.h>

#if HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#if HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#include "ext2_fs.h"

#include "ext2fs.h"

/*

 * This function reserves the superblock and block group descriptors

 * for a given block group.  It currently returns the number of free

 * blocks assuming that inode table and allocation bitmaps will be in

 * the group.  This is not necessarily the case when the flex_bg

 * feature is enabled, so callers should take care!  It was only

 * really intended for use by mke2fs, and even there it's not that

 * useful.  In the future, when we redo this function for 64-bit block

 * numbers, we should probably return the number of blocks used by the

 * super block and group descriptors instead.

 *

 * See also the comment for ext2fs_super_and_bgd_loc()

 */

int ext2fs_reserve_super_and_bgd(ext2_filsys fs,

         dgrp_t group,

         ext2fs_block_bitmap bmap)

{

  blk64_t super_blk, old_desc_blk, new_desc_blk;

  blk_t used_blks, old_desc_blocks, num_blocks;

  ext2fs_super_and_bgd_loc2(fs, group, &super_blk,

          &old_desc_blk, &new_desc_blk, &used_blks);

  if (ext2fs_has_feature_meta_bg(fs->super))

    old_desc_blocks = fs->super->s_first_meta_bg;

  else

    old_desc_blocks =

      fs->desc_blocks + fs->super->s_reserved_gdt_blocks;

  if (super_blk || (group == 0))

    ext2fs_mark_block_bitmap2(bmap, super_blk);

  if ((group == 0) && (fs->blocksize == 1024) &&

      EXT2FS_CLUSTER_RATIO(fs) > 1)

    ext2fs_mark_block_bitmap2(bmap, 0);

  if (old_desc_blk) {

    num_blocks = old_desc_blocks;

    if (old_desc_blk + num_blocks >= ext2fs_blocks_count(fs->super))

      num_blocks = ext2fs_blocks_count(fs->super) -

        old_desc_blk;

    ext2fs_mark_block_bitmap_range2(bmap, old_desc_blk, num_blocks);

  }

  if (new_desc_blk)

    ext2fs_mark_block_bitmap2(bmap, new_desc_blk);

  num_blocks = ext2fs_group_blocks_count(fs, group);

  num_blocks -= 2 + fs->inode_blocks_per_group + used_blks;

  return num_blocks  ;

}

/*

 * This function reserves the superblock and block group descriptors

 * for a given block group and returns the number of blocks used by the

 * super block and group descriptors by looking up the block bitmap.

 */

errcode_t ext2fs_reserve_super_and_bgd2(ext2_filsys fs,

                dgrp_t group,

                ext2fs_block_bitmap bmap,

                blk_t *desc_blocks)

{

  blk64_t num_blocks;

  errcode_t retval = 0;

  ext2fs_reserve_super_and_bgd(fs, group, bmap);

  retval = ext2fs_count_used_blocks(fs,

          ext2fs_group_first_block2(fs, group),

          ext2fs_group_last_block2(fs, group),

          &num_blocks);

  if (!retval)

    *desc_blocks = num_blocks;

  return retval;

}