block: introduce BLKDEV_DISCARD_ZERO to fix zeroout
Currently blkdev_issue_zeroout cascades down from discards (if the driver guarantees that discards zero data), to WRITE SAME and then to a loop writing zeroes. Unfortunately we ignore run-time EOPNOTSUPP errors in the block layer blkdev_issue_discard helper to work around DM volumes that may have mixed discard support underneath. This patch intoroduces a new BLKDEV_DISCARD_ZERO flag to blkdev_issue_discard that indicates we are called for zeroing operation. This allows both to ignore the EOPNOTSUPP hack and actually consolidating the discard_zeroes_data check into the function. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <axboe@fb.com>
Showing
想要评论请 注册 或 登录