question: private void rollBackVpoolOnVplexBackendVolume ( Volume volume , List < Volume > volumesToUpdate , DbClient dbClient , URI oldVpoolURI ) { Volume backendSrc = VPlexUtil . getVPLEXBackendVolume ( volume , true , dbClient , false ) ; if ( backendSrc != null ) { _log . info ( "Rolling back virtual pool on VPLEX backend Source volume {}({})" , backendSrc . getId ( ) , backendSrc . getLabel ( ) ) ; backendSrc . setVirtualPool ( oldVpoolURI ) ; _log . info ( "Set volume's virtual pool back to {}" , oldVpoolURI ) ; volumesToUpdate . add ( backendSrc ) ; Volume backendHa = VPlexUtil . getVPLEXBackendVolume ( volume , false , dbClient , false ) ; if ( backendHa != null ) { _log . info ( "Rolling back virtual pool on VPLEX backend Distributed volume {}({})" , backendHa . getId ( ) , backendHa . getLabel ( ) ) ; VirtualPool oldVpoolObj = dbClient . queryObject ( VirtualPool . class , oldVpoolURI ) ; VirtualPool oldHAVpool = VirtualPool . getHAVPool ( oldVpoolObj , dbClient ) ; if ( oldHAVpool == null ) { oldHAVpool = oldVpoolObj ; } backendHa . setVirtualPool ( oldHAVpool . getId ( ) ) ; _log . info ( "Set volume's virtual pool back to {}" , oldHAVpool . getId ( ) ) ; volumesToUpdate . add ( backendHa ) ; } } }
target:  Roll back vPool on vplex backend volumes.