write a lot of the persistent data classes

metadata.cc

@@ -0,0 +1,215 @@
+#include "metadata.h"
+
+#include <stdexcept>
+
+using namespace persistent_data;
+using namespace multisnap;
+
+//----------------------------------------------------------------
+
+namespace {
+	typedef uint8_t __le8;
+	typedef uint8_t __u8;
+	typedef uint32_t __le32;
+	typedef uint64_t __le64;
+
+
+
+	uint32_t const SUPERBLOCK_MAGIC = 27022010;
+	block_address const SUPERBLOCK_LOCATION = 0;
+        uint32_t const VERSION = 1;
+	unsigned const METADATA_CACHE_SIZE = 1024;
+        unsigned const SECTOR_TO_BLOCK_SHIFT = 3;
+	unsigned const SPACE_MAP_ROOT_SIZE = 128;
+
+	struct multisnap_super_block {
+		__le32 csum_;
+		__le32 flags_;
+		__le64 blocknr_; /* this block number, dm_block_t */
+
+		__u8 uuid_[16];
+		__le64 magic_;
+		__le32 version_;
+		__le32 time_;
+
+		__le64 trans_id_;
+		/* root for userspace's transaction (for migration and friends) */
+		__le64 held_root_;
+
+		__u8 data_space_map_root_[SPACE_MAP_ROOT_SIZE];
+		__u8 metadata_space_map_root_[SPACE_MAP_ROOT_SIZE];
+
+		/* 2 level btree mapping (dev_id, (dev block, time)) -> data block */
+		__le64 data_mapping_root_;
+
+		/* device detail root mapping dev_id -> device_details */
+		__le64 device_details_root_;
+
+		__le32 data_block_size_; /* in 512-byte sectors */
+
+		__le32 metadata_block_size_; /* in 512-byte sectors */
+		__le64 metadata_nr_blocks_;
+
+		__le32 compat_flags_;
+		__le32 incompat_flags_;
+	} __attribute__ ((packed));
+
+	struct device_details {
+		__le64 dev_size_;
+		__le64 mapped_blocks_;
+		__le64 transaction_id_;  /* when created */
+		__le32 creation_time_;
+		__le32 snapshotted_time_;
+	} __attribute__ ((packed));
+}
+
+//----------------------------------------------------------------
+
+metadata::thin::maybe_address
+metadata::thin::lookup(block_address thin_block)
+{
+	uint64_t key[2] = {dev_, thin_block};
+	return metadata_->mappings_.lookup(key);
+}
+
+void
+metadata::thin::insert(block_address thin_block, block_address data_block)
+{
+	uint64_t key[2] = {dev_, thin_block};
+	return metadata_->mappings_.insert(key, data_block);
+}
+
+void
+metadata::thin::remove(block_address thin_block)
+{
+	uint64_t key[2] = {dev_, thin_block};
+	metadata_->mappings_.remove(key);
+}
+#if 0
+//--------------------------------
+
+metadata::metadata(std::string const &metadata_dev,
+		   sector_t data_block_size,
+		   block_address nr_data_blocks)
+{
+
+}
+
+metadata::~metadata()
+{
+
+}
+
+void
+metadata::commit()
+{
+
+}
+#endif
+void
+metadata::create_thin(dev_t dev)
+{
+	uint64_t key[1] = {dev};
+
+	if (device_exists(dev))
+		throw std::runtime_error("Device already exists");
+
+	single_mapping_tree::ptr new_tree(new single_mapping_tree(tm_));
+	mappings_top_level_.insert(key, *new_tree);
+	mappings_.set_root(mappings_top_level_.get_root()); // FIXME: ugly
+}
+
+void
+metadata::create_snap(dev_t dev, dev_t origin)
+{
+	uint64_t snap_key[1] = {dev};
+	uint64_t origin_key[1] = {origin};
+
+	auto mtree = mappings_top_level_.lookup(origin_key);
+	if (!mtree)
+		throw std::runtime_error("unknown origin");
+
+	single_mapping_tree::ptr clone(mtree->clone());
+	mappings_top_level_.insert(snap_key, *clone);
+	mappings_.set_root(mappings_top_level_.get_root()); // FIXME: ugly
+
+	time_++;
+
+	auto o = open(origin);
+	auto s = open(dev);
+	o->set_snapshot_time(time_);
+	s->set_snapshot_time(time_);
+	s->set_mapped_blocks(o->get_mapped_blocks());
+}
+
+void
+metadata::del(dev_t dev)
+{
+	uint64_t key[1] = {dev};
+	mappings_top_level_.remove(key);
+}
+
+#if 0
+void
+metadata::set_transaction_id(uint64_t id)
+{
+
+}
+
+uint64_t
+metadata::get_transaction_id() const
+{
+
+}
+
+block_address
+metadata::get_held_root() const
+{
+
+}
+
+thin_ptr
+metadata::open_device(dev_t)
+{
+
+}
+
+block_address
+metadata::alloc_data_block()
+{
+
+}
+
+void
+metadata::free_data_block(block_address b)
+{
+
+}
+
+block_address
+metadata::get_nr_free_data_blocks() const
+{
+
+}
+
+sector_t
+metadata::get_data_block_size() const
+{
+
+}
+
+block_address
+metadata::get_data_dev_size() const
+{
+
+}
+#endif
+bool
+metadata::device_exists(dev_t dev) const
+{
+	uint64_t key[1] = {dev};
+	auto mval = details_.lookup(key);
+	return mval;
+}
+
+//----------------------------------------------------------------