Why are you even trying this again? As explained very clearly last time you can't change from a writeback-style to a write-through style I/O from the monitor without creating massive data integrity problems. See my patchset that allows changing this from the guest for how it should be done - I just need to get back and revisit the virtio protocol support for it.
- [Qemu-devel] [RFC Patch 0/3]Qemu: Enable dynamic cache c... Supriya Kannery
- [Qemu-devel] [RFC Patch 1/3]Qemu: Enhance "inf... Supriya Kannery
- Re: [Qemu-devel] [RFC Patch 1/3]Qemu: Enhance &... Kevin Wolf
- Re: [Qemu-devel] [RFC Patch 1/3]Qemu: Enhan... supriya kannery
- [Qemu-devel] [RFC Patch 2/3]Qemu: New error classes... Supriya Kannery
- [Qemu-devel] [RFC Patch 3/3]Qemu: Add command "... Supriya Kannery
- Re: [Qemu-devel] [RFC Patch 0/3]Qemu: Enable dynami... Christoph Hellwig
- Re: [Qemu-devel] [RFC Patch 0/3]Qemu: Enable dy... Anthony Liguori
- Re: [Qemu-devel] [RFC Patch 0/3]Qemu: Enabl... supriya kannery
- Re: [Qemu-devel] [RFC Patch 0/3]Qemu: Enabl... Christoph Hellwig
- Re: [Qemu-devel] [RFC Patch 0/3]Qemu: E... Supriya Kannery
- Re: [Qemu-devel] [RFC Patch 0/3]Qemu: Enable dy... supriya kannery