Re: [Xen-devel] earlier remove the backend of tapdisk device in xenstore to release the resource allocated in backend driver lies in dom0'kernel

["James (song wei)" <jsong@xxxxxxxxxx>]

Jim Fehlig wrote:
> 
>>Agreed.  qemu-dm should clean up these resources on shutdown.  AFAICT,
>>it currently relies on receiving CTRMSG_CLOSE from blktapctrl (see
>>ioemu-dir/hw/xen_blktap.c), which it may never receive before exiting.
> 
> No, I don't think so. The root cause in this issue is qemu-dm exit too
> earlier.  
> Qemu-dm has been destroyed before blktapctrl send "CTRMSG_CLOSE",
> moreover, removing the backend node in xenstore trigers the callback in
> blktapctrl to send "CTRMSG_CLOSE".  
> It's xend to decide who ought to be occured earlier between sending SIGHUP
> to qemu-dm and removing the backend node in xenstore.  Obviously, xend is
> the role of manager. So I think fix this issue in xend is appropriate.
> In addition,  If we really want to fix it in qemu, we have to intercept
> the exit signal sent by kill() in xend. I don't think intercept this
> singal in qemu for this point is proper.
> 
> -Jame (Song Wei)
> 
> 
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> 
> 

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