vbd_sz
if (unlikely(end > vbd_sz(vbd)))
unsigned long long new_size = vbd_sz(vbd);
(unsigned long long)vbd_sz(vbd));
if (unlikely(vbd->size != vbd_sz(vbd)))
vbd->size = vbd_sz(vbd);
(unsigned long long)vbd_sz(&be->blkif->vbd));