Comment 60 for bug 159031

I disconnected from Wifi while an sshfs was active, and the /mnt directory was inaccessible afterwords. "ls /mnt" hung. "sudo umount /mnt/mysshfs" hung. "sudo umount -f /mnt/mysshfs" said "target was busy". "sudo umount -l /mnt/mysshfs" worked. Though that's not a nice solution because the file is still busy somewhere, but it worked for me.