thin-provisioning-tools/persistent-data/space-maps/careful_alloc.cc
Joe Thornber 128ecc27f2 [space-maps] remove count_possibly_greater_than_one
This is only ever called with a recursive space map wrapper,
and that causes too many false positives.  False positives trigger
a copy of a metadata page, so this is a false economy.
2020-05-28 07:38:58 +01:00

136 lines
3.3 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/>.
#include "persistent-data/space-maps/careful_alloc.h"
#include "persistent-data/space-maps/subtracting_span_iterator.h"
using namespace std;
//----------------------------------------------------------------
namespace {
using namespace persistent_data;
class sm_careful_alloc : public checked_space_map {
public:
typedef std::shared_ptr<sm_careful_alloc> ptr;
sm_careful_alloc(checked_space_map::ptr sm)
: sm_(sm) {
}
virtual block_address get_nr_blocks() const {
return sm_->get_nr_blocks();
}
virtual block_address get_nr_free() const {
return sm_->get_nr_free();
}
virtual ref_t get_count(block_address b) const {
return sm_->get_count(b);
}
virtual void set_count(block_address b, ref_t c) {
if (!c && sm_->get_count(b))
mark_freed(b);
sm_->set_count(b, c);
}
virtual void commit() {
sm_->commit();
clear_freed();
}
virtual void inc(block_address b, ref_t count) override {
if (was_freed(b))
throw runtime_error("inc of block freed within current transaction");
sm_->inc(b, count);
}
virtual void dec(block_address b, ref_t count) override {
if (sm_->get_count(b) == count)
mark_freed(b);
sm_->dec(b, count);
}
virtual maybe_block find_free(span_iterator &it) {
subtracting_span_iterator filtered_it(get_nr_blocks(), it, freed_blocks_);
return sm_->find_free(filtered_it);
}
virtual void extend(block_address extra_blocks) {
return sm_->extend(extra_blocks);
}
virtual void iterate(iterator &it) const {
sm_->iterate(it);
}
virtual void count_metadata(block_counter &bc) const {
sm_->count_metadata(bc);
}
virtual size_t root_size() const {
return sm_->root_size();
}
virtual void copy_root(void *dest, size_t len) const {
return sm_->copy_root(dest, len);
}
virtual void visit(space_map_detail::visitor &v) const {
return sm_->visit(v);
}
virtual checked_space_map::ptr clone() const {
return checked_space_map::ptr(new sm_careful_alloc(sm_));
}
private:
void clear_freed() {
freed_blocks_.clear();
}
void mark_freed(block_address b) {
freed_blocks_.add(b, b + 1);
}
bool was_freed(block_address b) const {
return freed_blocks_.member(b) > 0;
}
checked_space_map::ptr sm_;
subtracting_span_iterator::block_set freed_blocks_;
};
}
//----------------------------------------------------------------
checked_space_map::ptr
persistent_data::create_careful_alloc_sm(checked_space_map::ptr sm)
{
return checked_space_map::ptr(new sm_careful_alloc(sm));
}
//----------------------------------------------------------------