[era] add in some wip files (transferring development to another machine)

era/bloom_tree.h

@@ -0,0 +1,112 @@
+#ifndef ERA_BLOOM_TREE_H
+#define ERA_BLOOM_TREE_H
+
+//----------------------------------------------------------------
+
+namespace era {
+}
+
+//----------------------------------------------------------------
+
+#endif
+
+
+#if 0
+	class dm_era {
+	public:
+		dm_era(block_address nr_blocks)
+		: nr_blocks_(nr_blocks),
+		  era_base_(0),
+		  base_(nr_blocks, false) {
+		}
+
+		set<block_address> blocks_written_since(unsigned era) const {
+
+		}
+
+		unsigned get_era() const {
+			return era_base_ + eras_.size() - 1;
+		}
+
+		void record_write(block_address b) {
+			current_era.record_write(b);
+		}
+
+		void resize(block_address new_size) {
+			nr_blocks_ = new_size;
+			push_era();
+			base_.resize(new_size, false);
+		}
+
+	private:
+		era_details &current_era() {
+			return eras_.back();
+		}
+
+		void need_new_era() {
+			// ???
+		}
+
+		void push_era() {
+			eras_.push_back(era(nr_blocks_));
+			if (eras_.size() > 100)
+				pop_era();
+		}
+
+		void pop_era() {
+			era_base_++;
+
+
+
+			eras_.pop_front();
+		}
+
+		static const unsigned NR_PROBES = 6;
+
+		class era_details {
+		public:
+			era_details(block_address nr_blocks)
+			: nr_blocks_(nr_blocks),
+			  f(power_bits(nr_blocks, NR_PROBES)) {
+			}
+
+			void record_write(block_address b) {
+				f.add(b);
+			}
+
+			void add_blocks_written(set<block_address &result) const {
+				for (block_address b = 0; b < nr_blocks; b++)
+					if (f.test(b))
+						result.insert(b);
+			}
+
+		private:
+			static unsigned power_bits(block_address nr_blocks) {
+				// We're expecting 1% of the cache to change per era
+				block_address expected_writes = nr_blocks / 100;
+
+				unsigned r = 1;
+				while ((1ull << r) < (16 * expected_writes))
+					r++;
+
+				return r;
+			}
+
+			typedef bloom_filter<block_address_bloom_traits> filter;
+
+			block_address nr_blocks;
+			filter f;
+		};
+
+		space_map::ptr setup_core_map() {
+			space_map::ptr sm(new core_map(NR_BLOCKS));
+			sm->inc(SUPERBLOCK);
+			return sm;
+		}
+
+		block_address nr_blocks_;
+		unsigned era_base_;
+		vector<bool> base_;
+		deque<era_details> eras_;
+	};
+#endif

era/superblock.cc

@@ -0,0 +1,118 @@
+#include "era/superblock.h"
+
+#include "persistent-data/checksum.h"
+
+using namespace base;
+using namespace era;
+using namespace persistent_data;
+
+//----------------------------------------------------------------
+
+namespace  {
+	using namespace base;
+
+	struct superblock_disk {
+		le32 csum;
+		le32 flags;
+		le64 blocknr;
+
+		__u8 uuid[16];
+		le64 magic;
+		le32 version;
+
+		le32 data_block_size;
+		le32 metadata_block_size;
+		le32 nr_blocks;
+
+		le32 current_era;
+		era_detail_disk current_detail;
+
+		le64 bloom_filters_root;
+		le64 era_array_root;
+	} __attribute__ ((packed));
+
+	struct superblock_traits {
+		typedef superblock_disk disk_type;
+		typedef superblock value_type;
+
+		static void unpack(disk_type const &disk, value_type &value);
+		static void pack(value_type const &value, disk_type &disk);
+	};
+
+	uint32_t const SUPERBLOCK_MAGIC = 2126579579;
+	uint32_t const VERSION_BEGIN = 1;
+	uint32_t const VERSION_END = 2;
+}
+
+//----------------------------------------------------------------
+
+superblock::superblock()
+	: csum(0),
+	  blocknr(0),
+	  flags(),
+	  magic(SUPERBLOCK_MAGIC),
+	  version(VERSION_END - 1),
+	  data_block_size(0),
+	  metadata_block_size(8),
+	  nr_blocks(0),
+	  current_era(0),
+	  era_root(0),
+	  era_array_root(0)
+{
+	memset(uuid, 0, sizeof(uuid));
+	memset(metadata_space_map_root, 0, sizeof(metadata_space_map_root));
+}
+
+//----------------------------------------------------------------
+
+namespace validator {
+	using namespace persistent_data;
+
+        uint32_t const VERSION = 1;
+        unsigned const SECTOR_TO_BLOCK_SHIFT = 3;
+	uint32_t const SUPERBLOCK_CSUM_SEED = 146538381;
+
+	// FIXME: turn into a template, we have 3 similar classes now
+	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());
+		}
+	};
+
+	block_manager<>::validator::ptr  mk_v() {
+		return block_manager<>::validator::ptr(new sb_validator);
+	}
+}
+
+//----------------------------------------------------------------
+
+superblock
+era::read_superblock(block_manager<>::ptr bm, block_address location)
+{
+	superblock sb;
+	block_manager<>::read_ref r = bm->read_lock(location, validator::mk_v());
+	superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(&r.data());
+	superblock_traits::unpack(*sbd, sb);
+
+	return sb;
+}
+
+void
+era::write_superblock(block_manager<>::ptr bm, superblock const &sb, block_address location)
+{
+	block_manager<>::write_ref w = bm->superblock_zero(location, validator::mk_v());
+	superblock_traits::pack(sb, *reinterpret_cast<superblock_disk *>(w.data().raw()));
+}
+
+//----------------------------------------------------------------

era/superblock.h

@@ -0,0 +1,84 @@
+#ifndef ERA_SUPERBLOCK_H
+#define ERA_SUPERBLOCK_h
+
+#include "persistent-data/block.h"
+#include "era/era_detail.h"
+
+#include <set>
+
+//----------------------------------------------------------------
+
+namespace era {
+	typedef unsigned char __u8;
+
+	class superblock_flags {
+	public:
+		enum flag {
+			CLEAN_SHUTDOWN
+		};
+
+		enum flag_bits {
+			CLEAN_SHUTDOWN_BIT = 0
+		};
+
+		superblock_flags();
+		superblock_flags(uint32_t bits);
+
+		void set_flag(flag f);
+		void clear_flag(flag f);
+		bool get_flag(flag f) const;
+		uint32_t encode() const;
+		uint32_t get_unhandled_flags() const;
+
+	private:
+		uint32_t unhandled_flags_;
+		std::set<flag> flags_;
+	};
+
+	unsigned const SPACE_MAP_ROOT_SIZE = 128;
+	uint64_t const SUPERBLOCK_LOCATION = 0;
+
+	struct superblock {
+		superblock();
+
+		uint32_t csum;
+		uint64_t blocknr;
+		superblock_flags flags;
+
+		__u8 uuid[16];	// FIXME: do we really need this?
+		uint64_t magic;
+		uint32_t version;
+
+		__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
+
+		uint32_t data_block_size;
+		uint32_t metadata_block_size;
+		uint32_t nr_blocks;
+
+		uint32_t current_era;
+		era_detail current_detail;
+
+		// A btree of undigested era_details
+		uint64_t era_root;
+
+		// Big array holding the digested era/block info.
+		uint64_t era_array_root;
+	};
+
+	//--------------------------------
+
+	superblock read_superblock(persistent_data::block_manager<>::ptr bm,
+				   persistent_data::block_address location = SUPERBLOCK_LOCATION);
+
+	void write_superblock(persistent_data::block_manager<>::ptr bm,
+			      superblock const &sb,
+			      persistent_data::block_address location = SUPERBLOCK_LOCATION);
+#if 0
+	void check_superblock(superblock const &sb,
+			      superblock_damage::damage_visitor &visitor);
+#endif
+}
+
+//----------------------------------------------------------------
+
+#endif