On Thu, Jul 16, 2009 at 08:24:09PM +0530, Harshavardhana wrote:
> Hi Daniel,
>
> On Thu, Jul 16, 2009 at 7:46 PM, Daniel P. Berrange <
berrange@redhat.com>wrote:
>
> > On Thu, Jul 16, 2009 at 06:06:25AM -0700, Harshavardhana wrote:
> > > New option index added to support -o options for various netfs.
> > > Currently added an option for glusterfs.
> >
> > What effect does it have ? Or why do we want/need it
> >
>
> Options could be required for filesystem to have few enhaced handling at the
> site where they will be under use. Correct approach for a configurable will
> be a new "XML" option in this case.
>
> Regarding current patch:
> This is required for the glusterfs to work properly with VM's. Right now
> there is a
> problem/difficulty in using direct-io based mechanism in the fuse kernel
> module
> when used with "XEN" in its "tap:aio" framework, we have seen xen vms hang
> over glusterfs or any fuse based filesystem due to fact that fuse module
> doesn't yet support "aio" with O_DIRECT internally as a kernel module. To
> have a work around fix we have to hardcode this value due to its usage in
> case of VM's.
>
> We are currently fixing this problem by fixing directly O_DIRECT problem in
> fuse. Which will be available in later releases for kernel.