128ecc27f2
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.
136 lines
3.3 KiB
C++
136 lines
3.3 KiB
C++
// Copyright (C) 2011 Red Hat, Inc. All rights reserved.
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//
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// This file is part of the thin-provisioning-tools source.
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//
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// thin-provisioning-tools is free software: you can redistribute it
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// and/or modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation, either version 3 of
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// the License, or (at your option) any later version.
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//
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// thin-provisioning-tools is distributed in the hope that it will be
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// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with thin-provisioning-tools. If not, see
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// <http://www.gnu.org/licenses/>.
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#include "persistent-data/space-maps/careful_alloc.h"
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#include "persistent-data/space-maps/subtracting_span_iterator.h"
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using namespace std;
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//----------------------------------------------------------------
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namespace {
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using namespace persistent_data;
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class sm_careful_alloc : public checked_space_map {
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public:
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typedef std::shared_ptr<sm_careful_alloc> ptr;
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sm_careful_alloc(checked_space_map::ptr sm)
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: sm_(sm) {
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}
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virtual block_address get_nr_blocks() const {
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return sm_->get_nr_blocks();
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}
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virtual block_address get_nr_free() const {
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return sm_->get_nr_free();
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}
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virtual ref_t get_count(block_address b) const {
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return sm_->get_count(b);
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}
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virtual void set_count(block_address b, ref_t c) {
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if (!c && sm_->get_count(b))
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mark_freed(b);
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sm_->set_count(b, c);
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}
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virtual void commit() {
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sm_->commit();
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clear_freed();
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}
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virtual void inc(block_address b, ref_t count) override {
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if (was_freed(b))
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throw runtime_error("inc of block freed within current transaction");
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sm_->inc(b, count);
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}
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virtual void dec(block_address b, ref_t count) override {
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if (sm_->get_count(b) == count)
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mark_freed(b);
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sm_->dec(b, count);
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}
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virtual maybe_block find_free(span_iterator &it) {
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subtracting_span_iterator filtered_it(get_nr_blocks(), it, freed_blocks_);
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return sm_->find_free(filtered_it);
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}
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virtual void extend(block_address extra_blocks) {
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return sm_->extend(extra_blocks);
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}
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virtual void iterate(iterator &it) const {
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sm_->iterate(it);
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}
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virtual void count_metadata(block_counter &bc) const {
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sm_->count_metadata(bc);
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}
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virtual size_t root_size() const {
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return sm_->root_size();
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}
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virtual void copy_root(void *dest, size_t len) const {
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return sm_->copy_root(dest, len);
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}
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virtual void visit(space_map_detail::visitor &v) const {
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return sm_->visit(v);
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}
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virtual checked_space_map::ptr clone() const {
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return checked_space_map::ptr(new sm_careful_alloc(sm_));
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}
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private:
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void clear_freed() {
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freed_blocks_.clear();
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}
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void mark_freed(block_address b) {
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freed_blocks_.add(b, b + 1);
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}
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bool was_freed(block_address b) const {
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return freed_blocks_.member(b) > 0;
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}
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checked_space_map::ptr sm_;
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subtracting_span_iterator::block_set freed_blocks_;
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};
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}
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//----------------------------------------------------------------
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checked_space_map::ptr
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persistent_data::create_careful_alloc_sm(checked_space_map::ptr sm)
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{
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return checked_space_map::ptr(new sm_careful_alloc(sm));
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}
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//----------------------------------------------------------------
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