Function allocFileSpace

src/common/isc_sync.cpp:1197–1236

}

bool allocFileSpace(int fd, off_t offset, FB_SIZE_T length, CheckStatusWrapper* statusVector)
{
#if defined(HAVE_LINUX_FALLOC_H) && defined(HAVE_FALLOCATE)
	if (fallocate(fd, 0, offset, length) == 0)
		return true;

	if (errno != EOPNOTSUPP && errno != ENOSYS)
	{
		reportError("fallocate", statusVector);
		return false;
	}
	// fallocate is not supported by this kernel or file system
	// take the long way around
#endif
	static const FB_SIZE_T buf128KSize = 131072;
	HalfStaticArray<UCHAR, BUFFER_LARGE> buf;
	const FB_SIZE_T bufSize = length < buf128KSize ? length : buf128KSize;

	memset(buf.getBuffer(bufSize), 0, bufSize);
	os_utils::lseek(fd, LSEEK_OFFSET_CAST offset, SEEK_SET);

	while (length)
	{
		const FB_SIZE_T cnt = length < bufSize ? length : bufSize;
		if (write(fd, buf.begin(), cnt) != (ssize_t) cnt)
		{
			reportError("write", statusVector);
			return false;
		}
		length -= cnt;
	}

	if (fsync(fd))
	{
		reportError("fsync", statusVector);
		return false;
	}

	return true;
}


void SharedMemoryBase::internalUnmap()