MD_NO_FUA
if ((op == REQ_OP_WRITE) && !test_bit(MD_NO_FUA, &device->flags))
clear_bit(MD_NO_FUA, &device->flags);
set_bit(MD_NO_FUA, &device->flags);
clear_bit(MD_NO_FUA, &device->flags);
set_bit(MD_NO_FUA, &device->flags);