How not to enable ACLs

Yesterday, I wanted to test something involving ACLs on my laptop, so I had to enable them on my laptop's filesystem.

Since I don't believe in multiple filesystems for a laptop, that meant changing mount options on the root filesystem. Changing fstab is easy enough, but for changing the options on the live filesystem, you need to remount it.

No problem, I thought, there's '-o remount', right?

mount -o remount,acl /

Turns out that's not such a good idea. This morning, I boot up my laptop, and I'm greeted with the following message:

/dev/hda4 superblock features are different from backup, check forced

... which took quite a while, as usual. Sigh.