If REQ_FAILFAST_TRANSPORT is set it means the driver should not retry
IO that completed with transport errors. REQ_FAILFAST_TRANSPORT is
set by multipathing software (e.g. dm-multipath) before it issues IO.
Update NVMe to allow failover of requests marked with either
REQ_NVME_MPATH or REQ_FAILFAST_TRANSPORT. This allows such requests
to be given a disposition of either FAILOVER or FAILUP respectively.
FAILUP handling ensures a retryable error is returned up from NVMe.
Introduce nvme_failup_req() for use in nvme_complete_rq() if
nvme_decide_disposition() returns FAILUP. nvme_failup_req() ensures
the request is completed with a retryable IO error when appropriate.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/nvme/host/core.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 4134cf3c7e48..605ffba6835f 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -299,6 +299,7 @@ enum nvme_disposition {
COMPLETE,
RETRY,
FAILOVER,
+ FAILUP,
};
static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
@@ -318,10 +319,11 @@ static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
nvme_req(req)->retries >= nvme_max_retries)
return COMPLETE;
- if (req->cmd_flags & REQ_NVME_MPATH) {
+ if (req->cmd_flags & (REQ_NVME_MPATH | REQ_FAILFAST_TRANSPORT)) {
if (nvme_is_path_error(nvme_req(req)->status) ||
blk_queue_dying(req->q))
- return FAILOVER;
+ return (req->cmd_flags & REQ_NVME_MPATH) ?
+ FAILOVER : FAILUP;
} else {
if (blk_queue_dying(req->q))
return COMPLETE;
@@ -343,6 +345,25 @@ static inline void nvme_end_req(struct request *req)
blk_mq_end_request(req, status);
}
+static void nvme_failup_req(struct request *req)
+{
+ blk_status_t status = nvme_error_status(nvme_req(req)->status);
+
+ /* Ensure a retryable path error is returned */
+ if (WARN_ON_ONCE(!blk_path_error(status))) {
+ /*
+ * If here, nvme_is_path_error() returned true.
+ * So nvme_error_status() translation needs updating
+ * relative to blk_path_error(), or vice versa.
+ */
+ pr_debug("Request meant for failover but blk_status_t (errno=%d) was not retryable.\n",
+ blk_status_to_errno(status));
+ nvme_req(req)->status = NVME_SC_HOST_PATH_ERROR;
+ }
+
+ nvme_end_req(req);
+}
+
void nvme_complete_rq(struct request *req)
{
trace_nvme_complete_rq(req);
@@ -361,6 +382,9 @@ void nvme_complete_rq(struct request *req)
case FAILOVER:
nvme_failover_req(req);
return;
+ case FAILUP:
+ nvme_failup_req(req);
+ return;
}
}
EXPORT_SYMBOL_GPL(nvme_complete_rq);
--
2.15.0
--
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