On Mon, Oct 31, 2022 at 11:26:36AM +0900, Damien Le Moal wrote: > + /* > + * REQ_FUA does not apply to read requests because: > + * - There is no way to reliably force media access for read operations > + * with a block device that does not support FUA. > + * - Not all block devices support FUA for read operations (e.g. ATA > + * devices with NCQ support turned off). > + */ > + if (!op_is_write(rq->cmd_flags) && (rq->cmd_flags & REQ_FUA)) { > + blk_mq_end_request(rq, BLK_STS_NOTSUPP); How could this even happen? If we want a debug check, I think it should be in submit_bio and a WARN_ON_ONCE.