thin-provisioning-tools/block-cache/copier.cc

138 lines
2.5 KiB
C++

#include "block-cache/copier.h"
#include <stdexcept>
using namespace bcache;
using namespace boost;
using namespace std;
//----------------------------------------------------------------
copier::copier(io_engine &engine,
string const &src, string const &dest,
sector_t block_size, size_t mem)
: pool_(block_size * 512, mem),
block_size_(block_size),
nr_blocks_(mem / block_size),
engine_(engine),
src_handle_(engine_.open_file(src, io_engine::READ_ONLY)),
dest_handle_(engine_.open_file(dest, io_engine::READ_WRITE)),
genkey_count_(0)
{
}
copier::~copier()
{
engine_.close_file(src_handle_);
engine_.close_file(dest_handle_);
}
void
copier::issue(copy_op const &op)
{
auto data = pool_.alloc();
if (!data) {
wait_();
data = pool_.alloc();
if (!data)
// Shouldn't get here
throw runtime_error("couldn't allocate buffer");
}
copy_job job(op, data);
job.op.read_complete = job.op.write_complete = false;
unsigned key = genkey(); // used as context for the io_engine
auto r = engine_.issue_io(src_handle_,
io_engine::READ,
to_sector(op.src_b),
to_sector(op.src_e),
data,
key);
if (r)
jobs_.insert(make_pair(key, job));
else
complete(job);
}
unsigned
copier::nr_pending() const
{
return jobs_.size() + complete_.size();
}
boost::optional<copy_op>
copier::wait()
{
while (!jobs_.empty() && complete_.empty())
wait_();
if (complete_.empty())
return optional<copy_op>();
else {
auto op = complete_.front();
complete_.pop_front();
return optional<copy_op>(op);
}
}
void
copier::wait_()
{
auto p = engine_.wait();
auto it = jobs_.find(p.second);
if (it == jobs_.end())
throw runtime_error("Internal error. Lost track of copy job.");
copy_job &j = it->second;
if (!p.first) {
// IO was unsuccessful
complete(j);
jobs_.erase(it);
return;
}
// IO was successful
if (!j.op.read_complete) {
j.op.read_complete = true;
if (!engine_.issue_io(dest_handle_,
io_engine::WRITE,
to_sector(j.op.dest_b),
to_sector(j.op.dest_b + (j.op.src_e - j.op.src_b)),
j.data,
it->first)) {
complete(j);
jobs_.erase(it);
}
} else {
j.op.write_complete = true;
complete(j);
jobs_.erase(it);
}
}
void
copier::complete(copy_job const &j)
{
pool_.free(j.data);
complete_.push_back(j.op);
}
sector_t
copier::to_sector(block_address b) const
{
return b * block_size_;
}
unsigned
copier::genkey()
{
return genkey_count_++;
}
//----------------------------------------------------------------