Hi Shaohua, You wrote: > BTW: blkdev_issue_zeroout retries if we immediately find the device doesn't > support zeroout, but it doesn't retry if submit_bio_wait returns -EOPNOTSUPP. > Is this correct behavior? I sent a patch for that yesterday, see "[PATCH] block: cope with WRITE SAME failing in blkdev_issue_zeroout()" on linux-block. It checks for -EREMOTEIO, because that's what I hit, but I wonder if it should check for -EOPNOTSUPP from submit_bio_wait() as well. Can you think of a case where, given bdev_write_zeroes_sectors() != 0, submit_bio_wait() would fail with -EOPNOTSUPP and we would want to do explicit zeroing? Please excuse broken threading. Thanks, Ilya