ea268a7016
live filesystem. To obtain a consistent dump image, dump takes a snapshot of the filesystem and then does a dump of the snapshot. The snapshot is removed when the dump is complete. Also add an operator warning that the `L' option should be used if dump is run on a live filesystem without the `L' option being specified. The alternative would be to silently use a snapshot any time that a live filesystem is dumped, but this change in dump semantics seemed too drastic at this time. Sponsored by: DARPA & NAI Labs. Approved by: re