This was interesting …
Logged into WordPress and found that I had a few plugins that could be upgraded. I clicked to “upgrade all” and clicked away like I normally do – it usually just finishes upgrading with no big deal. Unfortunately, this time, it got stuck. It said “Briefly unavailable for scheduled maintenance. Check back in a minute.” Well, after about 10 minutes, I got a little impatient and hit google.
Turned out that when upgrading, WordPress creates a file called .maintenance at the root level of your install (in the directory containing wp-admin).
If you take a look at what’s in the file, it looks like this:
cat .maintenance <?php $upgrading = 1377922367; ?>
It’s probably safe to just delete the file, but I thought I would rename it just in case I might need it. I renamed it and the blog came back and it appeared that the updates completed too. After doing that however, I renamed it back and it didn’t do anything. Kind of strange, but looks like I don’t have a problem, so I’m happy with it.