List, Please find a patch that updates the iscsi block device to provide support for 1, LUNs bigger than 2TB by switching to READCAPACITY16 2, Thin-provisioning by implementing bdrv_aio_discard using SCSI UNMAP commands.
The unmapping/discard of blocks was done by booting a guest and using sg_write_same --16 --unmap from within the guest. This was trapped in hw/scsi-disc.c and then appeared on the wire to the iscsi target as a proper SCSI UNMAP command. regards ronnie sahlberg