Re: [PATCH v5 1/2] loop: Report EOPNOTSUPP properly

[Chaitanya Kulkarni]

Looks good to me.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
On 05/06/2019 11:30 AM, Evan Green wrote:
> Properly plumb out EOPNOTSUPP from loop driver operations, which may
> get returned when for instance a discard operation is attempted but not
> supported by the underlying block device. Before this change, everything
> was reported in the log as an I/O error, which is scary and not
> helpful in debugging.
>
> Signed-off-by: Evan Green <evgreen@xxxxxxxxxxxx>
> Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
> Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
> Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
> ---
>
> Changes in v5: None
> Changes in v4: None
> Changes in v3:
> - Updated tags
>
> Changes in v2:
> - Unnested error if statement (Bart)
>
>   drivers/block/loop.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index bf1c61cab8eb..bbf21ebeccd3 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -458,7 +458,9 @@ static void lo_complete_rq(struct request *rq)
>
>   	if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) ||
>   	    req_op(rq) != REQ_OP_READ) {
> -		if (cmd->ret < 0)
> +		if (cmd->ret == -EOPNOTSUPP)
> +			ret = BLK_STS_NOTSUPP;
> +		else if (cmd->ret < 0)
>   			ret = BLK_STS_IOERR;
>   		goto end_io;
>   	}
> @@ -1892,7 +1894,10 @@ static void loop_handle_cmd(struct loop_cmd *cmd)
>    failed:
>   	/* complete non-aio request */
>   	if (!cmd->use_aio || ret) {
> -		cmd->ret = ret ? -EIO : 0;
> +		if (ret == -EOPNOTSUPP)
> +			cmd->ret = ret;
> +		else
> +			cmd->ret = ret ? -EIO : 0;
>   		blk_mq_complete_request(rq);
>   	}
>   }
>