On Wed, Nov 14 2018 at 2:49am -0500, Hannes Reinecke <h...@suse.de> wrote:
> On 11/14/18 6:38 AM, Mike Snitzer wrote: > >On Tue, Nov 13 2018 at 1:00pm -0500, > >Mike Snitzer <snit...@redhat.com> wrote: > > > >>[1]: > >>http://lists.infradead.org/pipermail/linux-nvme/2018-November/020765.html > >>[2]: https://www.redhat.com/archives/dm-devel/2018-November/msg00072.html > >... > > > >I knew there had to be a pretty tight coupling between the NVMe driver's > >native multipathing and ANA support... and that the simplicity of > >Hannes' patch [1] was too good to be true. > > > >The real justification for not making Hannes' change is it'd effectively > >be useless without first splitting out the ANA handling done during NVMe > >request completion (NVME_SC_ANA_* cases in nvme_failover_req) that > >triggers re-reading the ANA log page accordingly. > > > >So without the ability to drive the ANA workqueue to trigger > >nvme_read_ana_log() from the nvme driver's completion path -- even if > >nvme_core.multipath=N -- it really doesn't buy multipath-tools anything > >to have the NVMe driver export the ana state via sysfs, because that ANA > >state will never get updated. > > > Hmm. Indeed, I was more focussed on having the sysfs attributes > displayed, so yes, indeed it needs some more work. ... > >Not holding my breath BUT: > >if decoupling the reading of ANA state from native NVMe multipathing > >specific work during nvme request completion were an acceptable > >advancement I'd gladly do the work. > > > I'd be happy to work on that, given that we'll have to have 'real' > ANA support for device-mapper anyway for SLE12 SP4 etc. I had a close enough look yesterday that I figured I'd just implement what I reasoned through as one way forward, compile tested only (patch relative to Jens' for-4.21/block): drivers/nvme/host/core.c | 14 +++++++--- drivers/nvme/host/multipath.c | 65 ++++++++++++++++++++++++++----------------- drivers/nvme/host/nvme.h | 4 +++ 3 files changed, 54 insertions(+), 29 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index f172d63db2b5..05313ab5d91e 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -252,10 +252,16 @@ void nvme_complete_rq(struct request *req) trace_nvme_complete_rq(req); if (unlikely(status != BLK_STS_OK && nvme_req_needs_retry(req))) { - if ((req->cmd_flags & REQ_NVME_MPATH) && - blk_path_error(status)) { - nvme_failover_req(req); - return; + if (blk_path_error(status)) { + struct nvme_ns *ns = req->q->queuedata; + u16 nvme_status = nvme_req(req)->status; + + if (req->cmd_flags & REQ_NVME_MPATH) { + nvme_failover_req(req); + nvme_update_ana(ns, nvme_status); + return; + } + nvme_update_ana(ns, nvme_status); } if (!blk_queue_dying(req->q)) { diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 5e3cc8c59a39..f7fbc161dc8c 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -22,7 +22,7 @@ MODULE_PARM_DESC(multipath, inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl) { - return multipath && ctrl->subsys && (ctrl->subsys->cmic & (1 << 3)); + return ctrl->subsys && (ctrl->subsys->cmic & (1 << 3)); } /* @@ -47,6 +47,17 @@ void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns, } } +static bool nvme_ana_error(u16 status) +{ + switch (status & 0x7ff) { + case NVME_SC_ANA_TRANSITION: + case NVME_SC_ANA_INACCESSIBLE: + case NVME_SC_ANA_PERSISTENT_LOSS: + return true; + } + return false; +} + void nvme_failover_req(struct request *req) { struct nvme_ns *ns = req->q->queuedata; @@ -58,10 +69,7 @@ void nvme_failover_req(struct request *req) spin_unlock_irqrestore(&ns->head->requeue_lock, flags); blk_mq_end_request(req, 0); - switch (status & 0x7ff) { - case NVME_SC_ANA_TRANSITION: - case NVME_SC_ANA_INACCESSIBLE: - case NVME_SC_ANA_PERSISTENT_LOSS: + if (nvme_ana_error(status)) { /* * If we got back an ANA error we know the controller is alive, * but not ready to serve this namespaces. The spec suggests @@ -69,31 +77,38 @@ void nvme_failover_req(struct request *req) * that the admin and I/O queues are not serialized that is * fundamentally racy. So instead just clear the current path, * mark the the path as pending and kick of a re-read of the ANA - * log page ASAP. + * log page ASAP (see nvme_update_ana() below). */ nvme_mpath_clear_current_path(ns); - if (ns->ctrl->ana_log_buf) { - set_bit(NVME_NS_ANA_PENDING, &ns->flags); - queue_work(nvme_wq, &ns->ctrl->ana_work); + } else { + switch (status & 0x7ff) { + case NVME_SC_HOST_PATH_ERROR: + /* + * Temporary transport disruption in talking to the + * controller. Try to send on a new path. + */ + nvme_mpath_clear_current_path(ns); + break; + default: + /* + * Reset the controller for any non-ANA error as we + * don't know what caused the error. + */ + nvme_reset_ctrl(ns->ctrl); + break; } - break; - case NVME_SC_HOST_PATH_ERROR: - /* - * Temporary transport disruption in talking to the controller. - * Try to send on a new path. - */ - nvme_mpath_clear_current_path(ns); - break; - default: - /* - * Reset the controller for any non-ANA error as we don't know - * what caused the error. - */ - nvme_reset_ctrl(ns->ctrl); - break; } +} - kblockd_schedule_work(&ns->head->requeue_work); +void nvme_update_ana(struct nvme_ns *ns, u16 status) +{ + if (nvme_ana_error(status) && ns->ctrl->ana_log_buf) { + set_bit(NVME_NS_ANA_PENDING, &ns->flags); + queue_work(nvme_wq, &ns->ctrl->ana_work); + } + + if (multipath) + kblockd_schedule_work(&ns->head->requeue_work); } void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl) diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 32a1f1cfdfb4..8b4bc2054b7a 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -468,6 +468,7 @@ bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl); void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns, struct nvme_ctrl *ctrl, int *flags); void nvme_failover_req(struct request *req); +void nvme_update_ana(struct nvme_ns *ns, u16 status); void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl); int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl,struct nvme_ns_head *head); void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id); @@ -507,6 +508,9 @@ static inline void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns, static inline void nvme_failover_req(struct request *req) { } +static inline void nvme_update_ana(struct nvme_ns *ns, u16 status) +{ +} static inline void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl) { } -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
