ref: 63a33e39df4b7faedccb566ff9012d38e5b82064
dir: /lwext4/ext4_super.c/
/*
* Copyright (c) 2013 Grzegorz Kostka ([email protected])
*
*
* HelenOS:
* Copyright (c) 2012 Martin Sucha
* Copyright (c) 2012 Frantisek Princ
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup lwext4
* @{
*/
/**
* @file ext4_super.h
* @brief Superblock operations.
*/
#include <ext4_config.h>
#include <ext4_super.h>
uint32_t ext4_block_group_cnt(struct ext4_sblock *s)
{
uint64_t blocks_count = ext4_sb_get_blocks_cnt(s);
uint32_t blocks_per_group = ext4_get32(s, blocks_per_group);
uint32_t block_groups_count = blocks_count / blocks_per_group;
if (blocks_count % blocks_per_group)
block_groups_count++;
return block_groups_count;
}
uint32_t ext4_blocks_in_group_cnt(struct ext4_sblock *s, uint32_t bgid)
{
uint32_t block_group_count = ext4_block_group_cnt(s);
uint32_t blocks_per_group = ext4_get32(s, blocks_per_group);
uint64_t total_blocks = ext4_sb_get_blocks_cnt(s);
if (bgid < block_group_count - 1)
return blocks_per_group;
return (total_blocks - ((block_group_count - 1) * blocks_per_group));
}
uint32_t ext4_inodes_in_group_cnt(struct ext4_sblock *s, uint32_t bgid)
{
uint32_t block_group_count = ext4_block_group_cnt(s);
uint32_t inodes_per_group = ext4_get32(s, inodes_per_group);
uint32_t total_inodes = ext4_get32(s, inodes_count);
if (bgid < block_group_count - 1)
return inodes_per_group;
return (total_inodes - ((block_group_count - 1) * inodes_per_group));
}
int ext4_sb_write(struct ext4_blockdev *bdev, struct ext4_sblock *s)
{
return ext4_block_writebytes(bdev, EXT4_SUPERBLOCK_OFFSET,
s, EXT4_SUPERBLOCK_SIZE);
}
int ext4_sb_read(struct ext4_blockdev *bdev, struct ext4_sblock *s)
{
return ext4_block_readbytes(bdev, EXT4_SUPERBLOCK_OFFSET,
s, EXT4_SUPERBLOCK_SIZE);
}
bool ext4_sb_check(struct ext4_sblock *s)
{
if (ext4_get16(s, magic) != EXT4_SUPERBLOCK_MAGIC)
return false;
if (ext4_get32(s, inodes_count) == 0)
return false;
if (ext4_sb_get_blocks_cnt(s) == 0)
return false;
if (ext4_get32(s, blocks_per_group) == 0)
return false;
if (ext4_get32(s, inodes_per_group) == 0)
return false;
if (ext4_get16(s, inode_size) < 128)
return false;
if (ext4_get32(s, first_inode) < 11)
return false;
if (ext4_sb_get_desc_size(s) < EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE)
return false;
if (ext4_sb_get_desc_size(s) > EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
return false;
return true;
}
/**
* @}
*/