Messages in this thread | | | Subject | Re: [PATCH] virtio-blk: allow toggling host cache between writeback and writethrough | From | Badari Pulavarty <> | Date | Thu, 05 Jul 2012 11:39:10 -0700 |
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On Tue, 2012-07-03 at 15:19 +0200, Paolo Bonzini wrote: > This patch adds support for the new VIRTIO_BLK_F_CONFIG_WCE feature, > which exposes the cache mode in the configuration space and lets the > driver modify it. The cache mode is exposed via sysfs. > > Even if the host does not support the new feature, the cache mode is > visible (thanks to the existing VIRTIO_BLK_F_WCE), but not modifiable. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > ---
Hi Paolo,
Curious - What is the host side change to support this ? QEMU would close and re-open the device/file with the corresponding flags (O_SYNC) ?
And also, is there a way to expose cache=none (O_DIRECT) to the guest ? Our cluster filesystem folks need a way to verify/guarantee that virtio-blk device has cache=none selected at host. Otherwise, they can not support a cluster filesystem running inside a VM (on virtio-blk).
Thoughts ?
Thanks, Badari
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