void ext2fs_swap_group_desc2(ext2_filsys fs, struct ext2_group_desc *gdp)
{
struct ext4_group_desc *gdp4 = (struct ext4_group_desc *)gdp;
/* Do the 32-bit parts first */
gdp->bg_block_bitmap = ext2fs_swab32(gdp->bg_block_bitmap);
gdp->bg_inode_bitmap = ext2fs_swab32(gdp->bg_inode_bitmap);
gdp->bg_inode_table = ext2fs_swab32(gdp->bg_inode_table);
gdp->bg_free_blocks_count = ext2fs_swab16(gdp->bg_free_blocks_count);
gdp->bg_free_inodes_count = ext2fs_swab16(gdp->bg_free_inodes_count);
gdp->bg_used_dirs_count = ext2fs_swab16(gdp->bg_used_dirs_count);
gdp->bg_flags = ext2fs_swab16(gdp->bg_flags);
gdp->bg_exclude_bitmap_lo = ext2fs_swab32(gdp->bg_exclude_bitmap_lo);
gdp->bg_block_bitmap_csum_lo =
ext2fs_swab16(gdp->bg_block_bitmap_csum_lo);
gdp->bg_inode_bitmap_csum_lo =
ext2fs_swab16(gdp->bg_inode_bitmap_csum_lo);
gdp->bg_itable_unused = ext2fs_swab16(gdp->bg_itable_unused);
gdp->bg_checksum = ext2fs_swab16(gdp->bg_checksum);
/* If we're 32-bit, we're done */
if (fs == NULL || EXT2_DESC_SIZE(fs->super) < EXT2_MIN_DESC_SIZE_64BIT)
return;
/* Swap the 64-bit parts */
gdp4->bg_block_bitmap_hi = ext2fs_swab32(gdp4->bg_block_bitmap_hi);
gdp4->bg_inode_bitmap_hi = ext2fs_swab32(gdp4->bg_inode_bitmap_hi);
gdp4->bg_inode_table_hi = ext2fs_swab32(gdp4->bg_inode_table_hi);
gdp4->bg_free_blocks_count_hi =
ext2fs_swab16(gdp4->bg_free_blocks_count_hi);
gdp4->bg_free_inodes_count_hi =
ext2fs_swab16(gdp4->bg_free_inodes_count_hi);
gdp4->bg_used_dirs_count_hi =
ext2fs_swab16(gdp4->bg_used_dirs_count_hi);
gdp4->bg_itable_unused_hi = ext2fs_swab16(gdp4->bg_itable_unused_hi);
gdp4->bg_exclude_bitmap_hi = ext2fs_swab16(gdp4->bg_exclude_bitmap_hi);
gdp4->bg_block_bitmap_csum_hi =
ext2fs_swab16(gdp4->bg_block_bitmap_csum_hi);
gdp4->bg_inode_bitmap_csum_hi =
ext2fs_swab16(gdp4->bg_inode_bitmap_csum_hi);
}
// Return a pointer to the first block group descriptor in a filesystem. Real
// ext2 filesystems will have several of these, but, for simplicity, we will
// assume there is only one.
struct ext2_group_desc * get_block_group(void * fs, __u32 block_group_num) {
return fs + SUPERBLOCK_OFFSET + SUPERBLOCK_SIZE + block_group_num * EXT2_DESC_SIZE(get_super_block(fs));
}
/*
* This routine sanity checks the group descriptors
*/
errcode_t ext2fs_check_desc(ext2_filsys fs)
{
ext2fs_block_bitmap bmap;
errcode_t retval;
dgrp_t i;
blk64_t first_block = fs->super->s_first_data_block;
blk64_t last_block = ext2fs_blocks_count(fs->super)-1;
blk64_t blk, b;
unsigned int j;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (EXT2_DESC_SIZE(fs->super) & (EXT2_DESC_SIZE(fs->super) - 1))
return EXT2_ET_BAD_DESC_SIZE;
retval = ext2fs_allocate_subcluster_bitmap(fs, "check_desc map", &bmap);
if (retval)
return retval;
for (i = 0; i < fs->group_desc_count; i++)
ext2fs_reserve_super_and_bgd(fs, i, bmap);
for (i = 0; i < fs->group_desc_count; i++) {
if (!EXT2_HAS_INCOMPAT_FEATURE(fs->super,
EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
first_block = ext2fs_group_first_block2(fs, i);
last_block = ext2fs_group_last_block2(fs, i);
}
/*
* Check to make sure the block bitmap for group is sane
*/
blk = ext2fs_block_bitmap_loc(fs, i);
if (blk < first_block || blk > last_block ||
ext2fs_test_block_bitmap2(bmap, blk)) {
retval = EXT2_ET_GDESC_BAD_BLOCK_MAP;
goto errout;
}
ext2fs_mark_block_bitmap2(bmap, blk);
/*
* Check to make sure the inode bitmap for group is sane
*/
blk = ext2fs_inode_bitmap_loc(fs, i);
if (blk < first_block || blk > last_block ||
ext2fs_test_block_bitmap2(bmap, blk)) {
retval = EXT2_ET_GDESC_BAD_INODE_MAP;
goto errout;
}
ext2fs_mark_block_bitmap2(bmap, blk);
/*
* Check to make sure the inode table for group is sane
*/
blk = ext2fs_inode_table_loc(fs, i);
if (blk < first_block ||
((blk + fs->inode_blocks_per_group - 1) > last_block)) {
retval = EXT2_ET_GDESC_BAD_INODE_TABLE;
goto errout;
}
for (j = 0, b = blk; j < fs->inode_blocks_per_group;
j++, b++) {
if (ext2fs_test_block_bitmap2(bmap, b)) {
retval = EXT2_ET_GDESC_BAD_INODE_TABLE;
goto errout;
}
ext2fs_mark_block_bitmap2(bmap, b);
}
}
errout:
ext2fs_free_block_bitmap(bmap);
return retval;
}
