thin-provisioning-tools/persistent-data/space-maps/recursive.cc
2013-07-09 11:25:09 +01:00

306 lines
6.6 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/recursive.h"
#include "persistent-data/space-maps/subtracting_span_iterator.h"
using namespace persistent_data;
//----------------------------------------------------------------
namespace {
struct block_op {
enum op {
INC,
DEC,
SET
};
block_op(op o, block_address b)
: op_(o),
b_(b) {
if (o == SET)
throw runtime_error("SET must take an operand");
}
block_op(op o, block_address b, uint32_t rc)
: op_(o),
b_(b),
rc_(rc) {
if (o != SET)
throw runtime_error("only SET takes an operand");
}
op op_;
block_address b_;
uint32_t rc_;
};
class sm_recursive : public checked_space_map {
public:
sm_recursive(checked_space_map::ptr sm)
: sm_(sm),
depth_(0),
flush_in_progress_(false) {
}
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 {
ref_t count = sm_->get_count(b);
op_map::const_iterator ops_it = ops_.find(b);
if (ops_it != ops_.end()) {
list<block_op>::const_iterator it, end = ops_it->second.end();
for (it = ops_it->second.begin(); it != end; ++it) {
switch (it->op_) {
case block_op::INC:
count++;
break;
case block_op::DEC:
count--;
break;
case block_op::SET:
count = it->b_;
break;
}
}
}
return count;
}
virtual void set_count(block_address b, ref_t c) {
if (depth_)
add_op(block_op(block_op::SET, b, c));
else {
recursing_lock lock(*this);
return sm_->set_count(b, c);
}
}
virtual void commit() {
cant_recurse("commit");
sm_->commit();
}
virtual void inc(block_address b) {
if (depth_)
add_op(block_op(block_op::INC, b));
else {
recursing_lock lock(*this);
return sm_->inc(b);
}
}
virtual void dec(block_address b) {
if (depth_)
add_op(block_op(block_op::DEC, b));
else {
recursing_lock lock(*this);
return sm_->dec(b);
}
}
virtual maybe_block
find_free(span_iterator &it) {
recursing_lock lock(*this);
subtracting_span_iterator filtered_it(get_nr_blocks(), it, allocated_blocks_);
return sm_->find_free(filtered_it);
}
virtual bool count_possibly_greater_than_one(block_address b) const {
recursing_const_lock lock(*this);
bool gto = sm_->count_possibly_greater_than_one(b);
if (!gto) {
ref_t count = 1;
// FIXME: duplication
op_map::const_iterator ops_it = ops_.find(b);
if (ops_it != ops_.end()) {
list<block_op>::const_iterator it, end = ops_it->second.end();
for (it = ops_it->second.begin(); it != end; ++it) {
switch (it->op_) {
case block_op::INC:
count++;
break;
case block_op::DEC:
count--;
break;
case block_op::SET:
count = it->b_;
break;
}
}
}
gto = count > 1;
}
return gto;
}
virtual void extend(block_address extra_blocks) {
cant_recurse("extend");
recursing_lock lock(*this);
return sm_->extend(extra_blocks);
}
virtual void iterate(iterator &it) const {
sm_->iterate(it);
}
virtual size_t root_size() const {
cant_recurse("root_size");
recursing_const_lock lock(*this);
return sm_->root_size();
}
virtual void copy_root(void *dest, size_t len) const {
cant_recurse("copy_root");
recursing_const_lock lock(*this);
return sm_->copy_root(dest, len);
}
virtual void check(persistent_data::block_counter &counter) const {
cant_recurse("check");
recursing_const_lock lock(*this);
return sm_->check(counter);
}
virtual checked_space_map::ptr clone() const {
return checked_space_map::ptr(new sm_recursive(sm_->clone()));
}
void flush_ops() {
if (flush_in_progress_)
return;
flush_in_progress_ = true;
flush_ops_();
flush_in_progress_ = false;
}
private:
void flush_ops_() {
op_map::const_iterator it, end = ops_.end();
for (it = ops_.begin(); it != end; ++it) {
recursing_lock lock(*this);
list<block_op> const &ops = it->second;
list<block_op>::const_iterator op_it, op_end = ops.end();
for (op_it = ops.begin(); op_it != op_end; ++op_it) {
switch (op_it->op_) {
case block_op::INC:
sm_->inc(op_it->b_);
break;
case block_op::DEC:
sm_->dec(op_it->b_);
break;
case block_op::SET:
sm_->set_count(op_it->b_, op_it->rc_);
break;
}
}
}
ops_.clear();
allocated_blocks_.clear();
}
void add_op(block_op const &op) {
ops_[op.b_].push_back(op);
if (op.op_ == block_op::INC || (op.op_ == block_op::SET && op.rc_ > 0))
allocated_blocks_.add(op.b_, op.b_ + 1);
}
void cant_recurse(string const &method) const {
if (depth_)
throw runtime_error("recursive '" + method + "' not supported");
}
struct recursing_lock {
recursing_lock(sm_recursive &smr)
: smr_(smr) {
smr_.depth_++;
}
~recursing_lock() {
if (!--smr_.depth_)
smr_.flush_ops();
}
private:
sm_recursive &smr_;
};
struct recursing_const_lock {
recursing_const_lock(sm_recursive const &smr)
: smr_(smr) {
smr_.depth_++;
}
~recursing_const_lock() {
smr_.depth_--;
}
private:
sm_recursive const &smr_;
};
checked_space_map::ptr sm_;
mutable int depth_;
enum op {
BOP_INC,
BOP_DEC,
BOP_SET
};
typedef map<block_address, list<block_op> > op_map;
op_map ops_;
subtracting_span_iterator::block_set allocated_blocks_;
bool flush_in_progress_;
};
}
//----------------------------------------------------------------
checked_space_map::ptr
persistent_data::create_recursive_sm(checked_space_map::ptr sm)
{
return checked_space_map::ptr(new sm_recursive(sm));
}
//----------------------------------------------------------------