If the possibility of war with Iran were cause to fill up the SPR then one would think the West would be doing it also, but there are no public reports of this. I'm playing devils advocate and am not convinced war with Iran is the reason. I don't think war with Iran is that likely.
The reason western countries are not yet filling their SPR reserve is because they know when the attack will really occur while China doesn't have a clue, beside "soon".
It is almost certain that something huge will happen in the coming months for a simple reason. If people attention is not distracted from the global economic collapse, a spring revolution wiping capitalism off the planet could happen. They don't want to loose their power. They will invent anything to justify a war or mass murdering.
Will it be a war with Iran, a H5N5 virus, Hollywood like terrorist attack or whatever, be sure they won't let capitalism peacefully rust for the coming decades.