[PATCH v6 1/2] loop: Report EOPNOTSUPP properly

From: Evan Green
Date: Mon Nov 11 2019 - 14:01:50 EST


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>
Reviewed-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
---

Changes in v6:
- Updated tags

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 f6f77eaa7217..d749156a3d88 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;
}
@@ -1940,7 +1942,10 @@ 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);
}
}
--
2.21.0