def _reloadlvs(self, vgName, lvNames=None):
    lvNames = _normalizeargs(lvNames)
    cmd = list(LVS_CMD)
    if lvNames:
        cmd.extend(["%s/%s" % (vgName, lvName) for lvName in lvNames])
    else:
        cmd.append(vgName)

    rc, out, err = self.cmd(cmd, self._getVGDevs((vgName,)))

    with self._lock:
        if rc != 0:
            log.warning("lvm lvs failed: %s %s %s", str(rc), str(out),
                        str(err))
            lvNames = lvNames if lvNames else self._lvs.keys()
            for l in lvNames:
                if isinstance(self._lvs.get(l), Stub):
                    self._lvs[l] = Unreadable(self._lvs[l].name, True)
            return dict(self._lvs)

        updatedLVs = {}
        for line in out:
            fields = [field.strip() for field in line.split(SEPARATOR)]
            lv = makeLV(*fields)
            # For LV we are only interested in its first extent
        if lv.seg_start_pe == "0":
                self._lvs[(lv.vg_name, lv.name)] = lv
                updatedLVs[(lv.vg_name, lv.name)] = lv

        # Determine if there are stale LVs
        if lvNames:
            staleLVs = (lvName for lvName in lvNames
                        if (vgName, lvName) not in updatedLVs.iterkeys())
        else:
            # All the LVs in the VG
            staleLVs = (lvName for v, lvName in self._lvs.keys()
                        if (v == vgName) and
                        ((vgName, lvName) not in updatedLVs.iterkeys()))

        for lvName in staleLVs:
            log.warning("Removing stale lv: %s/%s", vgName, lvName)
            self._lvs.pop((vgName, lvName), None)

        log.debug("lvs reloaded")

    return updatedLVs