I have just tried to umount /usr on my test box in order to get all outstanding writes to be sync’ed to disk (as Kirk McKusick said, the umount system call will do true sync of a file system).

Unfortunatelly, I got some nasty prompts about lock and the system apparantly want to reboot as it occours. It’s late here and I tend to have some research on this issue tomorrow, and if this persists with a fresh built kernel, I tend to fix it and submit a patch.

The nectar commit yesterday is a fix related to vfs’s mount functionality. I’m not sure if the two are related.