thin-provisioning-tools/thin-provisioning/superblock.cc

#include "persistent-data/checksum.h"
#include "persistent-data/errors.h"
#include "thin-provisioning/superblock.h"

using namespace thin_provisioning;
using namespace superblock_detail;

//----------------------------------------------------------------

void
superblock_traits::unpack(superblock_disk const &disk, superblock &value)
{
	value.csum_ = to_cpu<uint32_t>(disk.csum_);
	value.flags_ = to_cpu<uint32_t>(disk.flags_);
	value.blocknr_ = to_cpu<uint64_t>(disk.blocknr_);

	::memcpy(value.uuid_, disk.uuid_, sizeof(value.uuid_));
	value.magic_ = to_cpu<uint64_t>(disk.magic_);
	value.version_ = to_cpu<uint32_t>(disk.version_);
	value.time_ = to_cpu<uint32_t>(disk.time_);

	value.trans_id_ = to_cpu<uint64_t>(disk.trans_id_);
	value.metadata_snap_ = to_cpu<uint64_t>(disk.metadata_snap_);

	::memcpy(value.data_space_map_root_,
		 disk.data_space_map_root_,
		 sizeof(value.data_space_map_root_));
	::memcpy(value.metadata_space_map_root_,
		 disk.metadata_space_map_root_,
		 sizeof(value.metadata_space_map_root_));

	value.data_mapping_root_ = to_cpu<uint64_t>(disk.data_mapping_root_);
	value.device_details_root_ = to_cpu<uint64_t>(disk.device_details_root_);
	value.data_block_size_ = to_cpu<uint32_t>(disk.data_block_size_);

	value.metadata_block_size_ = to_cpu<uint32_t>(disk.metadata_block_size_);
	value.metadata_nr_blocks_ = to_cpu<uint64_t>(disk.metadata_nr_blocks_);

	value.compat_flags_ = to_cpu<uint32_t>(disk.compat_flags_);
	value.compat_ro_flags_ = to_cpu<uint32_t>(disk.compat_ro_flags_);
	value.incompat_flags_ = to_cpu<uint32_t>(disk.incompat_flags_);
}

void
superblock_traits::pack(superblock const &value, superblock_disk &disk)
{
	disk.csum_ = to_disk<le32>(value.csum_);
	disk.flags_ = to_disk<le32>(value.flags_);
	disk.blocknr_ = to_disk<le64>(value.blocknr_);

	::memcpy(disk.uuid_, value.uuid_, sizeof(disk.uuid_));
	disk.magic_ = to_disk<le64>(value.magic_);
	disk.version_ = to_disk<le32>(value.version_);
	disk.time_ = to_disk<le32>(value.time_);

	disk.trans_id_ = to_disk<le64>(value.trans_id_);
	disk.metadata_snap_ = to_disk<le64>(value.metadata_snap_);

	::memcpy(disk.data_space_map_root_,
		 value.data_space_map_root_,
		 sizeof(disk.data_space_map_root_));
	::memcpy(disk.metadata_space_map_root_,
		 value.metadata_space_map_root_,
		 sizeof(disk.metadata_space_map_root_));

	disk.data_mapping_root_ = to_disk<le64>(value.data_mapping_root_);
	disk.device_details_root_ = to_disk<le64>(value.device_details_root_);
	disk.data_block_size_ = to_disk<le32>(value.data_block_size_);

	disk.metadata_block_size_ = to_disk<le32>(value.metadata_block_size_);
	disk.metadata_nr_blocks_ = to_disk<le64>(value.metadata_nr_blocks_);

	disk.compat_flags_ = to_disk<le32>(value.compat_flags_);
	disk.compat_ro_flags_ = to_disk<le32>(value.compat_ro_flags_);
	disk.incompat_flags_ = to_disk<le32>(value.incompat_flags_);
}

//----------------------------------------------------------------

namespace {
	using namespace persistent_data;
	using namespace superblock_detail;

        uint32_t const VERSION = 1;
        unsigned const SECTOR_TO_BLOCK_SHIFT = 3;
	uint32_t const SUPERBLOCK_CSUM_SEED = 160774;

	struct sb_validator : public bcache::validator {
		virtual void check(void const *raw, block_address location) const {
			superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(raw);
			crc32c sum(SUPERBLOCK_CSUM_SEED);
			sum.append(&sbd->flags_, MD_BLOCK_SIZE - sizeof(uint32_t));
			if (sum.get_sum() != to_cpu<uint32_t>(sbd->csum_))
				throw checksum_error("bad checksum in superblock");
		}

		virtual void prepare(void *raw, block_address location) const {
			superblock_disk *sbd = reinterpret_cast<superblock_disk *>(raw);
			crc32c sum(SUPERBLOCK_CSUM_SEED);
			sum.append(&sbd->flags_, MD_BLOCK_SIZE - sizeof(uint32_t));
			sbd->csum_ = to_disk<base::le32>(sum.get_sum());
		}
	};
}

bcache::validator::ptr
thin_provisioning::superblock_validator()
{
	return bcache::validator::ptr(new sb_validator);
}

//----------------------------------------------------------------

namespace thin_provisioning {
	namespace superblock_detail {
		namespace {
			unsigned const NEEDS_CHECK_BIT = 0;
		}

		bool
		superblock::get_needs_check_flag() const {
			return flags_ & (1 << NEEDS_CHECK_BIT);
		}

		void
		superblock::set_needs_check_flag(bool val) {
			if (val)
				flags_ |= (1 << NEEDS_CHECK_BIT);
			else
				flags_ &= ~(1 << NEEDS_CHECK_BIT);
		};

		superblock_corruption::superblock_corruption(std::string const &desc)
			: desc_(desc) {
		}

		void
		superblock_corruption::visit(damage_visitor &v) const {
			v.visit(*this);
		}

		void
		damage_visitor::visit(damage const &d) {
			d.visit(*this);
		}
	}

	superblock_detail::superblock read_superblock(block_manager<>::ptr bm, block_address location)
	{
		using namespace superblock_detail;

		superblock sb;
		block_manager<>::read_ref r = bm->read_lock(location, superblock_validator());
		superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(r.data());
		superblock_traits::unpack(*sbd, sb);
		return sb;
	}

	superblock_detail::superblock read_superblock(block_manager<>::ptr bm)
	{
		return read_superblock(bm, SUPERBLOCK_LOCATION);
	}

	void write_superblock(block_manager<>::ptr bm, superblock_detail::superblock const &sb)
	{
		block_manager<>::write_ref w = bm->write_lock(SUPERBLOCK_LOCATION, superblock_validator());
		superblock_disk *disk = reinterpret_cast<superblock_disk *>(w.data());
		superblock_traits::pack(sb, *disk);
	}

	void
	check_superblock(block_manager<>::ptr bm,
			 superblock_detail::damage_visitor &visitor) {
		using namespace superblock_detail;

		try {
			bm->read_lock(SUPERBLOCK_LOCATION, superblock_validator());

		} catch (std::exception const &e) {
			visitor.visit(superblock_corruption(e.what()));
		}
	}
}

//----------------------------------------------------------------