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 <jiangyiwen@huawei.com>
Suggested-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinicke <hare@suse.de>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Martin K. Petersen
2016-02-04 00:52:12 -05:00
parent 82c4331050
commit 0fb5b1fb30
3 changed files with 12 additions and 7 deletions

View File

@@ -2447,14 +2447,16 @@ struct request *blk_peek_request(struct request_queue *q)
rq = NULL;
break;
} else if (ret == BLKPREP_KILL) {
} else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) {
int err = (ret == BLKPREP_INVALID) ? -EREMOTEIO : -EIO;
rq->cmd_flags |= REQ_QUIET;
/*
* Mark this request as started so we don't trigger
* any debug logic in the end I/O path.
*/
blk_start_request(rq);
__blk_end_request_all(rq, -EIO);
__blk_end_request_all(rq, err);
} else {
printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
break;