Since v6: - This fixes a rather serious race condition in the previous versions, which only manifested itself when using 'snapshot=on'.
- Store the attributes (like filesize) in the state. - Macros for LOCK/UNLOCK to make debugging simpler. - Added an ssh driver to libguestfs and tested with that: https://www.redhat.com/archives/libguestfs/2013-April/msg00022.html Rich.
