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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#ifndef _LARGEFILE64_SOURCE
#define _LARGEFILE64_SOURCE
#endif // _LARGEFILE64_SOURCE
#include "librbd/migration/FileStream.h"
#include "common/dout.h"
#include "common/errno.h"
#include "librbd/AsioEngine.h"
#include "librbd/ImageCtx.h"
#include "librbd/asio/Utils.h"
#include <boost/asio/buffer.hpp>
#include <boost/asio/post.hpp>
#include <boost/asio/read.hpp>
#include <fcntl.h>
#include <unistd.h>
namespace librbd {
namespace migration {
namespace {
const std::string FILE_PATH {"file_path"};
} // anonymous namespace
#ifdef BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR
#define dout_subsys ceph_subsys_rbd
#undef dout_prefix
#define dout_prefix *_dout << "librbd::migration::FileStream::ReadRequest " \
<< this << " " << __func__ << ": "
template <typename I>
struct FileStream<I>::ReadRequest {
FileStream* file_stream;
io::Extents byte_extents;
bufferlist* data;
Context* on_finish;
size_t index = 0;
ReadRequest(FileStream* file_stream, io::Extents&& byte_extents,
bufferlist* data, Context* on_finish)
: file_stream(file_stream), byte_extents(std::move(byte_extents)),
data(data), on_finish(on_finish) {
auto cct = file_stream->m_cct;
ldout(cct, 20) << dendl;
}
void send() {
data->clear();
read();
}
void read() {
auto cct = file_stream->m_cct;
if (index >= byte_extents.size()) {
finish(0);
return;
}
auto& byte_extent = byte_extents[index++];
ldout(cct, 20) << "byte_extent=" << byte_extent << dendl;
auto ptr = buffer::ptr_node::create(buffer::create_small_page_aligned(
byte_extent.second));
auto buffer = boost::asio::mutable_buffer(
ptr->c_str(), byte_extent.second);
data->push_back(std::move(ptr));
int r;
auto offset = lseek64(file_stream->m_file_no, byte_extent.first, SEEK_SET);
if (offset == -1) {
r = -errno;
lderr(cct) << "failed to seek file stream: " << cpp_strerror(r) << dendl;
finish(r);
return;
}
boost::system::error_code ec;
size_t bytes_read = boost::asio::read(
*file_stream->m_stream_descriptor, std::move(buffer), ec);
r = -ec.value();
if (r < 0 && r != -ENOENT) {
lderr(cct) << "failed to read from file stream: " << cpp_strerror(r)
<< dendl;
finish(r);
return;
} else if (bytes_read < byte_extent.second) {
lderr(cct) << "failed to read " << byte_extent.second << " bytes from "
<< "file stream" << dendl;
finish(-ERANGE);
return;
}
// re-queue the remainder of the read requests
boost::asio::post(file_stream->m_strand, [this]() { read(); });
}
void finish(int r) {
auto cct = file_stream->m_cct;
ldout(cct, 20) << "r=" << r << dendl;
if (r < 0) {
data->clear();
}
on_finish->complete(r);
delete this;
}
};
#endif // BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR
#undef dout_prefix
#define dout_prefix *_dout << "librbd::migration::FileStream: " << this \
<< " " << __func__ << ": "
template <typename I>
FileStream<I>::FileStream(I* image_ctx, const json_spirit::mObject& json_object)
: m_cct(image_ctx->cct), m_asio_engine(image_ctx->asio_engine),
m_json_object(json_object),
m_strand(boost::asio::make_strand(*m_asio_engine)) {
}
template <typename I>
FileStream<I>::~FileStream() {
if (m_file_no != -1) {
::close(m_file_no);
}
}
#ifdef BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR
template <typename I>
void FileStream<I>::open(Context* on_finish) {
auto& file_path_value = m_json_object[FILE_PATH];
if (file_path_value.type() != json_spirit::str_type) {
lderr(m_cct) << "failed to locate '" << FILE_PATH << "' key" << dendl;
on_finish->complete(-EINVAL);
return;
}
auto& file_path = file_path_value.get_str();
ldout(m_cct, 10) << "file_path=" << file_path << dendl;
m_file_no = ::open(file_path.c_str(), O_RDONLY);
if (m_file_no < 0) {
int r = -errno;
lderr(m_cct) << "failed to open file stream '" << file_path << "': "
<< cpp_strerror(r) << dendl;
on_finish->complete(r);
return;
}
m_stream_descriptor = std::make_optional<
boost::asio::posix::stream_descriptor>(m_strand, m_file_no);
on_finish->complete(0);
}
template <typename I>
void FileStream<I>::close(Context* on_finish) {
ldout(m_cct, 10) << dendl;
m_stream_descriptor.reset();
on_finish->complete(0);
}
template <typename I>
void FileStream<I>::get_size(uint64_t* size, Context* on_finish) {
ldout(m_cct, 10) << dendl;
// execute IO operations in a single strand to prevent seek races
boost::asio::post(
m_strand, [this, size, on_finish]() {
auto offset = lseek64(m_file_no, 0, SEEK_END);
if (offset == -1) {
int r = -errno;
lderr(m_cct) << "failed to seek to file end: " << cpp_strerror(r)
<< dendl;
on_finish->complete(r);
return;
}
ldout(m_cct, 10) << "size=" << offset << dendl;
*size = offset;
on_finish->complete(0);
});
}
template <typename I>
void FileStream<I>::read(io::Extents&& byte_extents, bufferlist* data,
Context* on_finish) {
ldout(m_cct, 20) << byte_extents << dendl;
auto ctx = new ReadRequest(this, std::move(byte_extents), data, on_finish);
// execute IO operations in a single strand to prevent seek races
boost::asio::post(m_strand, [ctx]() { ctx->send(); });
}
#else // BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR
template <typename I>
void FileStream<I>::open(Context* on_finish) {
on_finish->complete(-EIO);
}
template <typename I>
void FileStream<I>::close(Context* on_finish) {
on_finish->complete(-EIO);
}
template <typename I>
void FileStream<I>::get_size(uint64_t* size, Context* on_finish) {
on_finish->complete(-EIO);
}
template <typename I>
void FileStream<I>::read(io::Extents&& byte_extents, bufferlist* data,
Context* on_finish) {
on_finish->complete(-EIO);
}
#endif // BOOST_ASIO_HAS_POSIX_STREAM_DESCRIPTOR
} // namespace migration
} // namespace librbd
template class librbd::migration::FileStream<librbd::ImageCtx>;
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