From 0fb5b1fb30fba3671dd5b1489d78e93e08d62e4e Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Thu, 4 Feb 2016 00:52:12 -0500 Subject: block/sd: Return -EREMOTEIO when WRITE SAME and DISCARD are disabled When a storage device rejects a WRITE SAME command we will disable write same functionality for the device and return -EREMOTEIO to the block layer. -EREMOTEIO will in turn prevent DM from retrying the I/O and/or failing the path. Yiwen Jiang discovered a small race where WRITE SAME requests issued simultaneously would cause -EIO to be returned. This happened because any requests being prepared after WRITE SAME had been disabled for the device caused us to return BLKPREP_KILL. The latter caused the block layer to return -EIO upon completion. To overcome this we introduce BLKPREP_INVALID which indicates that this is an invalid request for the device. blk_peek_request() is modified to return -EREMOTEIO in that case. Reported-by: Yiwen Jiang Suggested-by: Mike Snitzer Reviewed-by: Hannes Reinicke Reviewed-by: Ewan Milne Reviewed-by: Yiwen Jiang Signed-off-by: Martin K. Petersen --- drivers/scsi/sd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/scsi/sd.c') diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index ec163d08f6c3..6e841c6da632 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -761,7 +761,7 @@ static int sd_setup_discard_cmnd(struct scsi_cmnd *cmd) break; default: - ret = BLKPREP_KILL; + ret = BLKPREP_INVALID; goto out; } @@ -839,7 +839,7 @@ static int sd_setup_write_same_cmnd(struct scsi_cmnd *cmd) int ret; if (sdkp->device->no_write_same) - return BLKPREP_KILL; + return BLKPREP_INVALID; BUG_ON(bio_offset(bio) || bio_iovec(bio).bv_len != sdp->sector_size); -- cgit v1.2.3