Revision 0d4a2b733070a1bd52f981313f9e17f126701407 authored by Yi Wu on 04 August 2017, 20:09:56 UTC, committed by Facebook Github Bot on 04 August 2017, 20:12:07 UTC
Summary: The FsyncFiles background job call Fsync() periodically for blob files. However it can access WritableFileWriter concurrently with a Put() or Write(). And WritableFileWriter does not support concurrent access. It will lead to WritableFileWriter buffer being flush with same content twice, and blob file end up corrupted. Fixing by simply let FsyncFiles hold write_mutex_. Closes https://github.com/facebook/rocksdb/pull/2685 Differential Revision: D5561908 Pulled By: yiwu-arbug fbshipit-source-id: f0bb5bcab0e05694e053b8c49eab43640721e872
1 parent 627c9f1
channel.h
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include <condition_variable>
#include <mutex>
#include <queue>
#include <utility>
#pragma once
namespace rocksdb {
template <class T>
class channel {
public:
explicit channel() : eof_(false) {}
channel(const channel&) = delete;
void operator=(const channel&) = delete;
void sendEof() {
std::lock_guard<std::mutex> lk(lock_);
eof_ = true;
cv_.notify_all();
}
bool eof() {
std::lock_guard<std::mutex> lk(lock_);
return buffer_.empty() && eof_;
}
size_t size() const {
std::lock_guard<std::mutex> lk(lock_);
return buffer_.size();
}
// writes elem to the queue
void write(T&& elem) {
std::unique_lock<std::mutex> lk(lock_);
buffer_.emplace(std::forward<T>(elem));
cv_.notify_one();
}
/// Moves a dequeued element onto elem, blocking until an element
/// is available.
// returns false if EOF
bool read(T& elem) {
std::unique_lock<std::mutex> lk(lock_);
cv_.wait(lk, [&] { return eof_ || !buffer_.empty(); });
if (eof_ && buffer_.empty()) {
return false;
}
elem = std::move(buffer_.front());
buffer_.pop();
cv_.notify_one();
return true;
}
private:
std::condition_variable cv_;
std::mutex lock_;
std::queue<T> buffer_;
bool eof_;
};
} // namespace rocksdb
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