thin-provisioning-tools/persistent-data/space-maps/core.h
Joe Thornber d8a208cbc8 A stack of space map tweaks.
new_block() is now a concrete method implemented using the virtual
find_free() and inc() methods.

recursive space map is better at giving correct reference counts.
2013-04-23 10:57:47 +01:00

120 lines
2.8 KiB
C++

// 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 CORE_MAP_H
#define CORE_MAP_H
#include "persistent-data/space_map.h"
//----------------------------------------------------------------
namespace persistent_data {
class core_map : public checked_space_map {
public:
typedef boost::shared_ptr<core_map> ptr;
core_map(block_address nr_blocks)
: counts_(nr_blocks, 0),
nr_free_(nr_blocks) {
}
block_address get_nr_blocks() const {
return counts_.size();
}
block_address get_nr_free() const {
return nr_free_;
}
ref_t get_count(block_address b) const {
return counts_[b];
}
void set_count(block_address b, ref_t c) {
if (counts_[b] == 0 && c > 0)
nr_free_--;
else if (counts_[b] > 0 && c == 0)
nr_free_++;
counts_[b] = c;
}
void commit() {
}
void inc(block_address b) {
if (counts_[b] == 0)
nr_free_--;
counts_[b]++;
}
void dec(block_address b) {
counts_[b]--;
if (counts_[b] == 0)
nr_free_++;
}
maybe_block find_free(span_iterator &it) {
for (maybe_span ms = it.first(); ms; ms = it.next()) {
for (block_address b = ms->first; b < ms->second; b++) {
if (b >= counts_.size())
throw std::runtime_error("block out of bounds");
if (!counts_[b])
return maybe_block(b);
}
}
return maybe_block();
}
bool count_possibly_greater_than_one(block_address b) const {
return counts_[b] > 1;
}
void extend(block_address extra_blocks) {
throw std::runtime_error("'extend' not implemented");
}
// FIXME: meaningless, but this class is only used for testing
size_t root_size() const {
return 0;
}
// FIXME: meaningless, but this class is only used for testing
virtual void copy_root(void *dest, size_t len) const {
throw std::runtime_error("'copy root' not implemented");
}
checked_space_map::ptr clone() const {
return ptr(new core_map(*this));
}
private:
std::vector<ref_t> counts_;
unsigned nr_free_;
};
}
//----------------------------------------------------------------
#endif