caching/superblock.{h,cc}

caching/superblock.cc

@@ -0,0 +1,177 @@
+#include "caching/superblock.h"
+
+using namespace caching;
+using namespace superblock_detail;
+
+//----------------------------------------------------------------
+
+void
+superblock_traits::unpack(superblock_disk const &disk, superblock &core)
+{
+	core.csum = to_cpu<uint32_t>(disk.csum);
+	core.flags = to_cpu<uint32_t>(disk.flags);
+	core.blocknr = to_cpu<uint64_t>(disk.blocknr);
+
+	::memcpy(core.uuid, disk.uuid, sizeof(core.uuid));
+	core.magic = to_cpu<uint64_t>(disk.magic);
+	core.version = to_cpu<uint32_t>(disk.version);
+
+	::memcpy(core.policy_name, disk.policy_name, sizeof(core.policy_name));
+
+	for (unsigned i = 0; i < CACHE_POLICY_VERSION_SIZE; i++)
+		core.policy_version[i] = to_cpu<uint32_t>(disk.policy_version[i]);
+
+	core.policy_hint_size = to_cpu<uint32_t>(disk.policy_hint_size);
+
+	::memcpy(core.metadata_space_map_root,
+		 disk.metadata_space_map_root,
+		 sizeof(core.metadata_space_map_root));
+
+	core.mapping_root = to_cpu<uint64_t>(disk.mapping_root);
+	core.hint_root = to_cpu<uint64_t>(disk.hint_root);
+
+	core.discard_root = to_cpu<uint64_t>(disk.discard_root);
+	core.discard_block_size = to_cpu<uint64_t>(disk.discard_block_size);
+	core.discard_nr_blocks = to_cpu<uint64_t>(disk.discard_nr_blocks);
+
+	core.data_block_size = to_cpu<uint32_t>(disk.data_block_size);
+	core.metadata_block_size = to_cpu<uint32_t>(disk.metadata_block_size);
+	core.cache_blocks = to_cpu<uint32_t>(disk.cache_blocks);
+
+	core.compat_flags = to_cpu<uint32_t>(disk.compat_flags);
+	core.compat_ro_flags = to_cpu<uint32_t>(disk.compat_ro_flags);
+	core.incompat_flags = to_cpu<uint32_t>(disk.incompat_flags);
+
+	core.read_hits = to_cpu<uint32_t>(disk.read_hits);
+	core.read_misses = to_cpu<uint32_t>(disk.read_misses);
+	core.write_hits = to_cpu<uint32_t>(disk.write_hits);
+	core.write_misses = to_cpu<uint32_t>(disk.write_misses);
+}
+
+void
+superblock_traits::pack(superblock const &core, superblock_disk &disk)
+{
+	disk.csum = to_disk<le32>(core.csum);
+	disk.flags = to_disk<le32>(core.flags);
+	disk.blocknr = to_disk<le64>(core.blocknr);
+
+	::memcpy(disk.uuid, core.uuid, sizeof(disk.uuid));
+	disk.magic = to_disk<le64>(core.magic);
+	disk.version = to_disk<le32>(core.version);
+
+	::memcpy(disk.policy_name, core.policy_name, sizeof(disk.policy_name));
+
+	for (unsigned i = 0; i < CACHE_POLICY_VERSION_SIZE; i++)
+		disk.policy_version[i] = to_disk<le32>(core.policy_version[i]);
+
+	disk.policy_hint_size = to_disk<le32>(core.policy_hint_size);
+
+	::memcpy(disk.metadata_space_map_root,
+		 core.metadata_space_map_root,
+		 sizeof(disk.metadata_space_map_root));
+
+	disk.mapping_root = to_disk<le64>(core.mapping_root);
+	disk.hint_root = to_disk<le64>(core.hint_root);
+
+	disk.discard_root = to_disk<le64>(core.discard_root);
+	disk.discard_block_size = to_disk<le64>(core.discard_block_size);
+	disk.discard_nr_blocks = to_disk<le64>(core.discard_nr_blocks);
+
+	disk.data_block_size = to_disk<le32>(core.data_block_size);
+	disk.metadata_block_size = to_disk<le32>(core.metadata_block_size);
+	disk.cache_blocks = to_disk<le32>(core.cache_blocks);
+
+	disk.compat_flags = to_disk<le32>(core.compat_flags);
+	disk.compat_ro_flags = to_disk<le32>(core.compat_ro_flags);
+	disk.incompat_flags = to_disk<le32>(core.incompat_flags);
+
+	disk.read_hits = to_disk<le32>(core.read_hits);
+	disk.read_misses = to_disk<le32>(core.read_misses);
+	disk.write_hits = to_disk<le32>(core.write_hits);
+	disk.write_misses = to_disk<le32>(core.write_misses);
+}
+
+//--------------------------------
+
+superblock_corruption::superblock_corruption(std::string const &desc)
+	: desc_(desc)
+{
+}
+
+void
+superblock_corruption::visit(damage_visitor &v) const
+{
+	v.visit(*this);
+}
+
+//--------------------------------
+
+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 = 9031977;
+
+	struct sb_validator : public block_manager<>::validator {
+		virtual void check(buffer<> const &b, block_address location) const {
+			superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(&b);
+			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(buffer<> &b, block_address location) const {
+			superblock_disk *sbd = reinterpret_cast<superblock_disk *>(&b);
+			crc32c sum(SUPERBLOCK_CSUM_SEED);
+			sum.append(&sbd->flags, MD_BLOCK_SIZE - sizeof(uint32_t));
+			sbd->csum = to_disk<base::le32>(sum.get_sum());
+		}
+	};
+}
+
+persistent_data::block_manager<>::validator::ptr
+caching::superblock_validator()
+{
+	return block_manager<>::validator::ptr(new sb_validator);
+}
+
+//--------------------------------
+
+superblock_detail::superblock
+caching::read_superblock(persistent_data::block_manager<>::ptr bm,
+			 persistent_data::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
+caching::read_superblock(persistent_data::block_manager<>::ptr bm)
+{
+	return read_superblock(bm, SUPERBLOCK_LOCATION);
+}
+
+void
+caching::check_superblock(persistent_data::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()));
+	}
+}
+
+//----------------------------------------------------------------