Re: [PATCH V3 3/3] virtio-blk: Add bio-based IO path for virtio-blk

Il 30/07/2012 06:43, Asias He ha scritto:

quoted

Yes. Something like this:

  qemu -drive file=foo.img,cache=writeback/unsafe

is not safe against power losses also?

cache=writeback and cache=none are safe, cache=unsafe isn't.

I think we can add REQ_FLUSH & REQ_FUA support to bio path and that
deserves another patch.

You only need to add REQ_FLUSH support.  The virtio-blk protocol does
not support REQ_FUA, because there's no easy way to do it in userspace.

Paolo