294cc35f3d
This adds the wr_highest_sector blockstat which implements what is generally known as the high watermark. It is the highest offset of a sector written to the respective BlockDriverState since it has been opened. The query-blockstat QMP command is extended to add this value to the result, and also to add the statistics of the underlying protocol in a new "parent" field. Note that to get the "high watermark" of a qcow2 image, you need to look into the wr_highest_sector field of the parent (which can be a file, a host_device, ...). The wr_highest_sector of the qcow2 BlockDriverState itself is the highest offset on the _virtual_ disk that the guest has written to. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Read the documentation in qemu-doc.html. Fabrice Bellard.