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 <[email protected]> --- 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 -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
