On Fri, Sep 08, 2023 at 12:20:14PM +0200, Jan Kara wrote: > Well, currently you click some "Eject / safely remove / whatever" button > and then you get a "wait" dialog until everything is done after which > you're told the stick is safe to remove. What I imagine is that the "wait" > dialog needs to be there while there are any (or exclusive at minimum) openers > of the device. Not until umount(2) syscall has returned. And yes, the > kernel doesn't quite make that easy - the best you can currently probably > do is to try opening the device with O_EXCL and if that fails, you know > there's some other exclusive open. ... and the simple answer to the problem is to have an event notification for when the super_block has finally been destroyed. That way the application gets this notification directly instead of having to make a process synchronous that fundamentally isn't as explained in this thread.
