Re: ignoring xenbus state transitions during shutdown

[Keir Fraser <keir@xensource.com>]

Unless you care about domU kexec, you can pretty safely remove that
system_state() check, so long as you remove the .shutdown callback hooks (in
the same file) too.

 -- Keir

On 25/6/07 19:41, "David Lively" <dlively@virtualiron.com> wrote:

> Hi Folks -
>   In otherend_changed() in xenbus_probe.c, the driver is trying to
> ignore xenbus state transitions while the guest OS is shutting down.  It
> currently does this by looking for system_state > SYSTEM_RUNNING.  But
> system_state is not exported by some kernels that use it (e.g., SLES9
> running in a HVM guest), so the xenbus driver can't be loaded.
>   The comments indicate we're trying to avoid a failure that occurs when
> there is no rootfs.  I haven't yet seen this failure (after removing the
> code my shutdowns with PV drivers seemed to work fine, though I haven't
> pushed hard yet), but I suspect I shouldn't be ignoring it.  I was
> thinking it might be better to test for the screw condition (no rootfs)
> directly, perhaps something like try vfs_stat("/", &stat) and see
> whether it fails (??).  (These state transitions are relatively rare, so
> it doesn't need to be a particularly cheap test.)
>   Any other suggestions?  I've heard of the old global 'system_running',
> but that's not used SLES9, at least.
> 
> Thanks in Advance,
> Dave
> 
> 
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