Filelock: SoftFileLock Removes A Live Holder's Marker When Another User Forges The PID In A Writable Marker

"SoftFileLock", "MarkerSoftFileLock", "SoftFileLease", their async variants and a "FileLock" that has fallen back to a soft lock on "ENOSYS" decide from the record inside the marker file whether its owner is gone. The marker is the file whose presence says a process holds the lock. They do not...