I am running Linux and want to safely unmount my external HDD.
I want to use
Lazy unmount. Detach the filesystem from the file hierarchy now, and clean up all references to this filesystem as soon as it is not busy anymore. (Requires kernel 2.4.11 or later.)
After the last reference to the filesystem is closed, I'm assuming that a
sync will be performed.
How do I know when that
sync is complete?