Write Same can return an error asynchronously if it turns out the underlying SCSI device does not support Write Same, which makes a proper fallback to other methods in __blkdev_issue_zeroout impossible. Thus only issue a Write Same from blkdev_issue_zeroout an don't try it at all from __blkdev_issue_zeroout as a non-invasive workaround. Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Junichi Nomura <j-nomura@ce.jp.nec.com> Fixes: e73c23ff ("block: add async variant of blkdev_issue_zeroout") Tested-by: Junichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Jens Axboe <axboe@fb.com>