FreeBSD Security Advisory FreeBSD-SA-04:01.mksnap_ffs - The mksnap_ffs command creates a snapshot of a filesystem. A snapshot is a static representation of the state of the filesystem at a particular point in time. The kernel interface for creating a snapshot of a filesystem is the same as that for changing the flags on that filesystem. Due to an oversight, the mksnap_ffs command called that interface with only the snapshot flag set, causing all other flags to be reset to the default value.