[libvirt] [PATCH] qemu: support nospace reason in io error event

[Eric Blake]

On 10/03/2014 10:26 AM, Michal Privoznik wrote:
> On 03.10.2014 17:03, Eric Blake wrote:
>> Aeons ago (commit 34dcbbb4, v0.8.2), we added a new libvirt event
>> (VIR_DOMAIN_EVENT_ID_IO_ERROR_REASON) in order to tell the user WHY
>> the guest halted.  This is because at least VDSM wants to react
>> differently to ENOSPC events (resize the lvm partition to be larger,
>> and resume the guest as if nothing had happened) from all other events
>> (I/O is hosed, throw up our hands and flag things as broken).  At the
>> time this was done, downstream RHEL qemu added a vendor extension
>> '__com.redhat_reason', which would be exactly one of these strings:
>> "enospc", "eperm", "eio", and "eother".  In our stupidity, we exposed
>> those exact strings to clients, rather than an enum, and we also
>> return "" if we did not have access to a reason (which was the case
>> for upstream qemu).
>>
>> Fast forward to now: upstream qemu commit c7c2ff0c (will be qemu 2.2)
>> FINALLY adds a 'nospace' boolean, after discussion with multiple
>> projects determined that VDSM really doesn't care about distinction
>> between any other error types.  So this patch converts 'nospace' into
>> the string "enospc" for compatibility with RHEL clients that were
>> already used to the downstream extension, while leaving the reason
>> blank for all other cases (no change from the status quo).
>>
>> See also https://bugzilla.redhat.com/show_bug.cgi?id=1119784
>>

>>
> 
> ACK

Thanks; pushed.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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