On 10/03/2016 18:37, Stefan Hajnoczi wrote: > I suggest giving the new NBD command a "type" argument: > 0 - SCSI mapped/anchored values according to SCSI Get LBA Status > 1 - Dirty/clean, useful for incremental backup and other blocking tracking > cases > > This way we don't impinge on SCSI semantics and the command can be > used for both traditional logical block provisioning and dirty bitmap > info. > > When the NBD export is started in QEMU you can optionally associate it > with a bitmap. This bitmap is used to provide type=1 (dirty/clean) > status information.
Good idea. The precedent in NBD is to use bits 16..31 of the command for flags, so it could go there. Paolo
