Merge "Retry write operation when getting ENOBUFS." into oc-dev (e6b7328b) · Commits · e / os / android_system_core

libappfuse/FuseBuffer.cc

+30 −21

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

		constexpr useconds_t kRetrySleepForWriting = 1000; // 1 ms

		template <typename T>
		bool CheckHeaderLength(const FuseMessage<T>* self, const char* name, size_t max_size) {
		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 auto& header = static_cast<const T*>(self)->header;

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

		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;
		}
		default:
		PLOG(ERROR) << "Failed to write a FUSE message";
		return ResultOrAgain::kFailure;
		}

		}
		CHECK(static_cast<uint32_t>(result) == header.len);
		return ResultOrAgain::kSuccess;
		}
		}
		}

		static_assert(std::is_standard_layout<FuseBuffer>::value,
		"FuseBuffer must be standard layout union.");
		@@ -161,7 +170,7 @@ bool FuseMessage<T>::Write(int fd) const {
		template <typename T>
		bool FuseMessage<T>::WriteWithBody(int fd, size_t max_size, const void* data) const {
		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>