Method truncate

fdbrpc/include/fdbrpc/AsyncFileKAIO.actor.h:289–344

		return success ? Void() : IAsyncFile::zeroRange(offset, length);
	}
	Future<Void> truncate(int64_t size) override {
		++countFileLogicalWrites;
		++countLogicalWrites;

		if (failed) {
			return io_timeout();
		}

#if KAIO_LOGGING
		uint32_t id = OpLogEntry::nextID();
#endif
		int result = -1;
		KAIOLogEvent(logFile, id, OpLogEntry::TRUNCATE, OpLogEntry::START, size / 4096);
		bool completed = false;
		double begin = timer_monotonic();

		if (ctx.fallocateSupported && size >= lastFileSize) {
			result = fallocate(fd, 0, 0, size);
			if (result != 0) {
				int fallocateErrCode = errno;
				TraceEvent("AsyncFileKAIOAllocateError")
				    .detail("Fd", fd)
				    .detail("Filename", filename)
				    .detail("Size", size)
				    .GetLastError();
				if (fallocateErrCode == EOPNOTSUPP) {
					// Mark fallocate as unsupported. Try again with truncate.
					ctx.fallocateSupported = false;
				} else {
					KAIOLogEvent(logFile, id, OpLogEntry::TRUNCATE, OpLogEntry::COMPLETE, size / 4096, result);
					return io_error();
				}
			} else {
				completed = true;
			}
		}
		if (!completed)
			result = ftruncate(fd, size);

		double end = timer_monotonic();
		if (nondeterministicRandom()->random01() < end - begin) {
			TraceEvent("SlowKAIOTruncate")
			    .detail("TruncateTime", end - begin)
			    .detail("TruncateBytes", size - lastFileSize);
		}
		KAIOLogEvent(logFile, id, OpLogEntry::TRUNCATE, OpLogEntry::COMPLETE, size / 4096, result);

		if (result != 0) {
			TraceEvent("AsyncFileKAIOTruncateError").detail("Fd", fd).detail("Filename", filename).GetLastError();
			return io_error();
		}

		lastFileSize = nextFileSize = size;

		return Void();
	}

	ACTOR static Future<Void> throwErrorIfFailed(Reference<AsyncFileKAIO> self, Future<Void> sync) {