thin-provisioning-tools/cache/cache_metadata.h

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2013-03-15 20:29:21 +05:30
// Copyright (C) 2011 Red Hat, Inc. All rights reserved.
//
// This file is part of the thin-provisioning-tools source.
//
// thin-provisioning-tools is free software: you can redistribute it
// and/or modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation, either version 3 of
// the License, or (at your option) any later version.
//
// thin-provisioning-tools is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with thin-provisioning-tools. If not, see
// <http://www.gnu.org/licenses/>.
#ifndef CACHE_METADATA_H
#define CACHE_METADATA_H
#include "block.h"
#include "array.h"
#include "endian_utils.h"
#include "space_map_disk.h"
#include "transaction_manager.h"
//----------------------------------------------------------------
namespace cache {
// FIXME: don't use namespaces in a header
using namespace base;
using namespace persistent_data;
block_address const SUPERBLOCK_LOCATION = 0;
typedef uint64_t sector_t;
//------------------------------------------------
class space_map_ref_counter {
public:
space_map_ref_counter(space_map::ptr sm)
: sm_(sm) {
}
void inc(block_address b) {
sm_->inc(b);
}
void dec(block_address b) {
sm_->dec(b);
}
private:
space_map::ptr sm_;
};
struct block_flags {
uint64_t block_;
uint32_t flags_;
};
class block_flags_ref_counter {
public:
block_flags_ref_counter(space_map::ptr sm)
: sm_(sm) {
}
void inc(block_flags bf) {
sm_->inc(bf.block_);
}
void dec(block_flags bf) {
sm_->dec(bf.block_);
}
private:
space_map::ptr sm_;
};
struct block_traits {
typedef base::__le64 disk_type;
typedef block_flags value_type;
typedef block_flags_ref_counter ref_counter;
static void unpack(disk_type const &disk, value_type &value) {
uint64_t v = to_cpu<uint64_t>(disk);
value.block_ = v >> 24;
value.flags_ = v & ((1 << 24) - 1);
}
static void pack(value_type const &value, disk_type &disk) {
uint64_t v = (value.block_ << 24) | value.flags_;
disk = base::to_disk<base::__le64>(v);
}
};
//------------------------------------------------
// FIXME: should these be in a sub-namespace?
typedef persistent_data::transaction_manager::ptr tm_ptr;
typedef persistent_data::btree<1, device_details_traits> detail_tree;
typedef persistent_data::btree<1, mtree_traits> dev_tree;
typedef persistent_data::btree<2, block_traits> mapping_tree;
typedef persistent_data::btree<1, block_traits> single_mapping_tree;
// The tools require different interfaces onto the metadata than
// the in kernel driver. This class gives access to the low-level
// implementation of metadata. Implement more specific interfaces
// on top of this.
struct metadata {
enum open_type {
CREATE,
OPEN
};
metadata(std::string const &dev_path, open_type ot,
sector_t data_block_size = 128,
block_address nr_cache_blocks = 0); // Only used if CREATE
metadata(std::string const &dev_path, block_address metadata_snap);
void commit();
typedef block_manager<>::read_ref read_ref;
typedef block_manager<>::write_ref write_ref;
typedef boost::shared_ptr<metadata> ptr;
tm_ptr tm_;
superblock sb_;
checked_space_map::ptr metadata_sm_;
checked_space_map::ptr data_sm_;
detail_tree::ptr details_;
dev_tree::ptr mappings_top_level_;
mapping_tree::ptr mappings_;
};
}
//----------------------------------------------------------------
#endif