[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Rebooting domu fails in nfs share exported from another domu on the same dom0
On Thu, Jul 17, 2014 at 12:56:12PM -0400, annie li wrote: > > On 2014/7/17 11:49, Roger Pau Monné wrote: > >On 16/07/14 22:36, annie li wrote: > >>Hi > >> > >>I hit a problem in such scenario: vm1 is running and export nfs service, > >>dom0 mount this nfs, and vm2 is booted in this nfs location. vm1 and vm2 > >>are running on the same dom0. > >> > >>When this bug happens, the data flow is: vm2 blkfront-> vm2 blkback-> I am a bit confused here. 'vm2 blkfront -> vm2 blkback'? Did you mean 'dom0 blkback'? > >>loop -> nfs file -> nfs client -> bridge priv1 -> vm1 vif -> vm1 netback > >>-> vm1 netfront. So both netback and netfront run in the same guest? I think you want these two swapped around (netfront -> netback). > >> > >>In above data flow, nfs implements direct io, blkfront and blkback uses > >>grantmap. This makes page mapping works well through vm2 blkfront to vm1 > >>netback. However, when netback does grant copy, the error happens in > >>this routine: > >If it's the same error I was seeing (which I think it is), the problem > >is due to trying to do a grant_copy with the PFN of a grant mapped page > >in Dom0, which Xen refuses to perform. > > > >I've never followed it up, but I think the problem should be fixed in > >Linux, so that netback realises it is trying to perform a grant_copy to > >a granted page, and use the grant ref instead of the PFN. > > > > I guess the routine is similar if using grant ref. See __gnttab_copy > function, > The routine goes into __acquire_grant_for_copy for grant ref, and then > __get_paged_frame->get_page_from_gfn->get_page. get_page is where the > checking page owner fails. > > Thanks > Annie > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxx > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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