On 08/30/2010 10:20 PM, Jan Kara wrote:

  My setup is that I have a dedicated partition / drive for a filesystem
which is written to from a guest kernel running under KVM. I have set it up
using virtio driver with cache=writeback so that the host caches the writes
in a similar way disk caches them. At some point I just kill the qemu-kvm
process and at that point I'd like to also throw away data cached by the
host...

$ echo 1 > /sys/block/sdX/device/delete
$ echo - - - > /sys/class/scsi_host/hostX/scan

should do the trick.

Thanks.

-- 
tejun