thin-provisioning-tools/persistent-data/space_map_careful_alloc.cc
Joe Thornber 186b0aa6c1 Change the signature of the space_map->new_block() method, introducing
a span_iterator abstraction.

Rename sm_transactional -> sm_careful_alloc.  Still not happy with the name.

Fix failing test.
2013-01-10 21:05:10 +00:00

190 lines
4.5 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_map_careful_alloc.h"
#include <set>
//----------------------------------------------------------------
namespace {
class sm_careful_alloc : public checked_space_map {
private:
typedef set<block_address> block_set;
public:
typedef 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) {
if (was_freed(b))
throw runtime_error("inc of block freed within current transaction");
sm_->inc(b);
}
virtual void dec(block_address b) {
sm_->dec(b);
if (!sm_->get_count(b))
mark_freed(b);
}
// FIXME: rewrite with tests using the run_list stuff.
class no_freed_blocks_iterator : public span_iterator {
public:
no_freed_blocks_iterator(span_iterator &sub_it,
block_set const &freed_blocks)
: sub_it_(sub_it),
freed_blocks_(freed_blocks) {
}
virtual maybe_span first() {
current_span_ = sub_it_.first();
if (current_span_)
current_begin_ = current_span_->first;
return next();
}
virtual maybe_span next() {
if (!current_span_)
return current_span_;
if (current_begin_ == current_span_->second) {
current_span_ = sub_it_.next();
if (!current_span_)
return current_span_;
current_begin_ = current_span_->first;
}
// FIXME: slow
while (current_begin_ != current_span_->second &&
freed_blocks_.count(current_begin_))
current_begin_++;
block_address b = current_begin_;
// FIXME: factor out common code
while (current_begin_ != current_span_->second &&
!freed_blocks_.count(current_begin_))
current_begin_++;
block_address e = current_begin_;
return maybe_span(span(b, e));
}
private:
span_iterator &sub_it_;
block_set const &freed_blocks_;
maybe_span current_span_;
block_address current_begin_;
};
virtual maybe_block new_block(span_iterator &it) {
no_freed_blocks_iterator filtered_it(it, freed_blocks_);
return sm_->new_block(filtered_it);
}
virtual bool count_possibly_greater_than_one(block_address b) const {
return sm_->count_possibly_greater_than_one(b);
}
virtual void extend(block_address extra_blocks) {
return sm_->extend(extra_blocks);
}
virtual void iterate(iterator &it) const {
sm_->iterate(it);
}
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 check(block_counter &counter) const {
return sm_->check(counter);
}
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_.insert(b);
}
bool was_freed(block_address b) const {
return freed_blocks_.count(b) > 0;
}
checked_space_map::ptr sm_;
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));
}
//----------------------------------------------------------------