Merge "Retry write operation when getting ENOBUFS." into oc-dev (5dd7bc78) · Commits · e / os / android_system_core

libappfuse/FuseBuffer.cc

+30 −21

Original line number	Original line	Diff line number	Diff line
	@@ -34,6 +34,8 @@ namespace android {
	namespace fuse {		namespace fuse {
	namespace {		namespace {

			constexpr useconds_t kRetrySleepForWriting = 1000; // 1 ms

	template <typename T>		template <typename T>
	bool CheckHeaderLength(const FuseMessage<T>* self, const char* name, size_t max_size) {		bool CheckHeaderLength(const FuseMessage<T>* self, const char* name, size_t max_size) {
	const auto& header = static_cast<const T*>(self)->header;		const auto& header = static_cast<const T*>(self)->header;
	@@ -91,6 +93,7 @@ ResultOrAgain WriteInternal(const FuseMessage<T>* self, int fd, int sockflag, co
	const char* const buf = reinterpret_cast<const char*>(self);		const char* const buf = reinterpret_cast<const char*>(self);
	const auto& header = static_cast<const T*>(self)->header;		const auto& header = static_cast<const T*>(self)->header;

			while (true) {
	int result;		int result;
	if (sockflag) {		if (sockflag) {
	CHECK(data == nullptr);		CHECK(data == nullptr);
	@@ -102,19 +105,25 @@ ResultOrAgain WriteInternal(const FuseMessage<T>* self, int fd, int sockflag, co
	} else {		} else {
	result = TEMP_FAILURE_RETRY(write(fd, buf, header.len));		result = TEMP_FAILURE_RETRY(write(fd, buf, header.len));
	}		}

	if (result == -1) {		if (result == -1) {
	if (errno == EAGAIN) {		switch (errno) {
			case ENOBUFS:
			// When returning ENOBUFS, epoll still reports the FD is writable. Just usleep
			// and retry again.
			usleep(kRetrySleepForWriting);
			continue;
			case EAGAIN:
	return ResultOrAgain::kAgain;		return ResultOrAgain::kAgain;
	}		default:
	PLOG(ERROR) << "Failed to write a FUSE message";		PLOG(ERROR) << "Failed to write a FUSE message";
	return ResultOrAgain::kFailure;		return ResultOrAgain::kFailure;
	}		}
			}
	CHECK(static_cast<uint32_t>(result) == header.len);		CHECK(static_cast<uint32_t>(result) == header.len);
	return ResultOrAgain::kSuccess;		return ResultOrAgain::kSuccess;
	}		}
	}		}
			}

	static_assert(std::is_standard_layout<FuseBuffer>::value,		static_assert(std::is_standard_layout<FuseBuffer>::value,
	"FuseBuffer must be standard layout union.");		"FuseBuffer must be standard layout union.");
	@@ -161,7 +170,7 @@ bool FuseMessage<T>::Write(int fd) const {
	template <typename T>		template <typename T>
	bool FuseMessage<T>::WriteWithBody(int fd, size_t max_size, const void* data) const {		bool FuseMessage<T>::WriteWithBody(int fd, size_t max_size, const void* data) const {
	CHECK(data != nullptr);		CHECK(data != nullptr);
	return WriteInternal<T>(this, fd, 0, data, max_size) == ResultOrAgain::kSuccess;		return WriteInternal(this, fd, 0, data, max_size) == ResultOrAgain::kSuccess;
	}		}

	template <typename T>		template <typename T>