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;
if (!ext4_sb_verify_csum(s))
return false;
return true;
}
uint32_t ext4_num_base_meta_clusters(struct ext4_sblock *s,
uint32_t block_group)
{
uint32_t num;
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
num = ext4_sb_is_super_in_bg(s, block_group);
if (!ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG) ||
block_group < ext4_sb_first_meta_bg(s) * dsc_per_block) {
if (num) {
num += ext4_bg_num_gdb(s, block_group);
num += ext4_get16(s, s_reserved_gdt_blocks);
}
} else {
num += ext4_bg_num_gdb(s, block_group);
}
uint32_t clustersize = 1024 << ext4_get32(s, log_cluster_size);
uint32_t cluster_ratio = clustersize / ext4_sb_get_block_size(s);
uint32_t v =
(num + cluster_ratio - 1) >> ext4_get32(s, log_cluster_size);
return v;
}
uint32_t ext4_bg_num_gdb(struct ext4_sblock *s, uint32_t group)
{
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
uint32_t first_meta_bg = ext4_sb_first_meta_bg(s);
uint32_t metagroup = group / dsc_per_block;
if (!ext4_sb_feature_incom(s,EXT4_FINCOM_META_BG) ||
metagroup < first_meta_bg)
return ext4_bg_num_gdb_nometa(s, group);
return ext4_bg_num_gdb_meta(s, group);
}
static uint32_t ext4_bg_num_gdb_meta(struct ext4_sblock *s, uint32_t group)
{
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
uint32_t metagroup = group / dsc_per_block;
uint32_t first = metagroup * dsc_per_block;
uint32_t last = first + dsc_per_block - 1;
if (group == first || group == first + 1 || group == last)
return 1;
return 0;
}
static uint32_t ext4_bg_num_gdb_nometa(struct ext4_sblock *s, uint32_t group)
{
if (!ext4_sb_is_super_in_bg(s, group))
return 0;
uint32_t dsc_per_block =
ext4_sb_get_block_size(s) / ext4_sb_get_desc_size(s);
uint32_t db_count =
(ext4_block_group_cnt(s) + dsc_per_block - 1) / dsc_per_block;
if (ext4_sb_feature_incom(s, EXT4_FINCOM_META_BG))
return ext4_sb_first_meta_bg(s);
return db_count;
}
checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
sizeof(sb->uuid));
/* Then calculate crc32 checksum against block_group_desc */
checksum = ext4_crc32c(checksum, bitmap, blocks_per_group / 8);
}
return checksum;
}
#else
#define ext4_balloc_bitmap_csum(...) 0
#endif
void ext4_balloc_set_bitmap_csum(struct ext4_sblock *sb,
struct ext4_bgroup *bg,
void *bitmap __unused)
{
int desc_size = ext4_sb_get_desc_size(sb);
uint32_t checksum = ext4_balloc_bitmap_csum(sb, bitmap);
uint16_t lo_checksum = to_le16(checksum & 0xFFFF),
hi_checksum = to_le16(checksum >> 16);
if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
return;
/* See if we need to assign a 32bit checksum */
bg->block_bitmap_csum_lo = lo_checksum;
if (desc_size == EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
bg->block_bitmap_csum_hi = hi_checksum;
}
#if CONFIG_META_CSUM_ENABLE
