[PATCH v3] nvme: revalidate paths during rescan

[PATCH v3] nvme: revalidate paths during rescan

[Daniel Wagner]

From: Hannes Reinecke <hare@suse.de>

When triggering a rescan due to a namespace resize we will be
receiving AENs on every controller, triggering a rescan of all
attached namespaces. If multipath is active only the current path and
the ns_head disk will be updated, the other paths will still refer to
the old size until AENs for the remaining controllers are received.

If I/O comes in before that it might be routed to one of the old
paths, triggering an I/O failure with 'access beyond end of device'.
With this patch the old paths are skipped from multipath path
selection until the controller serving these paths has been rescanned.

Signed-off-by: Hannes Reinecke <hare@suse.de>
[dwagner: - introduce NVME_NS_READY flag instead of NVME_NS_INVALIDATE
          - use 'revalidate' instead of 'invalidate' which
	    follows the zoned device code path.]
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
v3:
  - Renamed nvme_mpath_invalidated_paths to nvme_mpath_revalidate_paths()
  - Replaced NVME_NS_INVALIDATE with NVME_NS_READY
v2:
  - https://lore.kernel.org/linux-nvme/20210730071059.124347-1-dwagner@suse.de/
  - removed churn from failed rebase.
v1:
  - https://lore.kernel.org/linux-nvme/20210729194630.i5mhvvgb73duojqq@beryllium.lan/

drivers/nvme/host/core.c      |  3 +++
 drivers/nvme/host/multipath.c | 17 ++++++++++++++++-
 drivers/nvme/host/nvme.h      |  5 +++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2f0cbaba12ac..54aafde4f556 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1878,6 +1878,7 @@ static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_id_ns *id)
 			goto out_unfreeze;
 	}
 
+	set_bit(NVME_NS_READY, &ns->flags);
 	blk_mq_unfreeze_queue(ns->disk->queue);
 
 	if (blk_queue_is_zoned(ns->queue)) {
@@ -1889,6 +1890,7 @@ static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_id_ns *id)
 	if (nvme_ns_head_multipath(ns->head)) {
 		blk_mq_freeze_queue(ns->head->disk->queue);
 		nvme_update_disk_info(ns->head->disk, ns, id);
+		nvme_mpath_revalidate_paths(ns);
 		blk_stack_limits(&ns->head->disk->queue->limits,
 				 &ns->queue->limits, 0);
 		blk_queue_update_readahead(ns->head->disk->queue);
@@ -3816,6 +3818,7 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 	if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
 		return;
 
+	clear_bit(NVME_NS_READY, &ns->flags);
 	set_capacity(ns->disk, 0);
 	nvme_fault_inject_fini(&ns->fault_inject);
 
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 3f32c5e86bfc..d390f14b8bb6 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -147,6 +147,21 @@ void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
 	mutex_unlock(&ctrl->scan_lock);
 }
 
+void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
+{
+	struct nvme_ns_head *head = ns->head;
+	sector_t capacity = get_capacity(head->disk);
+	int node;
+
+	for_each_node(node)
+		rcu_assign_pointer(head->current_path[node], NULL);
+
+	list_for_each_entry_rcu(ns, &head->list, siblings) {
+		if (capacity != get_capacity(ns->disk))
+			clear_bit(NVME_NS_READY, &ns->flags);
+	}
+}
+
 static bool nvme_path_is_disabled(struct nvme_ns *ns)
 {
 	/*
@@ -158,7 +173,7 @@ static bool nvme_path_is_disabled(struct nvme_ns *ns)
 	    ns->ctrl->state != NVME_CTRL_DELETING)
 		return true;
 	if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
-	    test_bit(NVME_NS_REMOVING, &ns->flags))
+	    !test_bit(NVME_NS_READY, &ns->flags))
 		return true;
 	return false;
 }
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 26511794629b..6c67dac79168 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -468,6 +468,7 @@ struct nvme_ns {
 #define NVME_NS_DEAD     	1
 #define NVME_NS_ANA_PENDING	2
 #define NVME_NS_FORCE_RO	3
+#define NVME_NS_READY		4
 
 	struct cdev		cdev;
 	struct device		cdev_device;
@@ -760,6 +761,7 @@ void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl);
 void nvme_mpath_uninit(struct nvme_ctrl *ctrl);
 void nvme_mpath_stop(struct nvme_ctrl *ctrl);
 bool nvme_mpath_clear_current_path(struct nvme_ns *ns);
+void nvme_mpath_revalidate_paths(struct nvme_ns *ns);
 void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl);
 void nvme_mpath_shutdown_disk(struct nvme_ns_head *head);
 
@@ -807,6 +809,9 @@ static inline bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
 {
 	return false;
 }
+static inline void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
+{
+}
 static inline void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
 {
 }
-- 
2.29.2

Re: [PATCH v3] nvme: revalidate paths during rescan

[Daniel Wagner]

On Wed, Aug 11, 2021 at 05:28:03PM +0200, Daniel Wagner wrote:
> From: Hannes Reinecke <hare@suse.de>
> 
> When triggering a rescan due to a namespace resize we will be
> receiving AENs on every controller, triggering a rescan of all
> attached namespaces. If multipath is active only the current path and
> the ns_head disk will be updated, the other paths will still refer to
> the old size until AENs for the remaining controllers are received.
> 
> If I/O comes in before that it might be routed to one of the old
> paths, triggering an I/O failure with 'access beyond end of device'.
> With this patch the old paths are skipped from multipath path
> selection until the controller serving these paths has been rescanned.

ping

Re: [PATCH v3] nvme: revalidate paths during rescan

[Christoph Hellwig]

Thanks,

applied to nvme-5.15.

Re: [PATCH v3] nvme: revalidate paths during rescan

[Sagi Grimberg]

On 8/11/21 8:28 AM, Daniel Wagner wrote:
> From: Hannes Reinecke <hare@suse.de>
> 
> When triggering a rescan due to a namespace resize we will be
> receiving AENs on every controller, triggering a rescan of all
> attached namespaces. If multipath is active only the current path and
> the ns_head disk will be updated, the other paths will still refer to
> the old size until AENs for the remaining controllers are received.
> 
> If I/O comes in before that it might be routed to one of the old
> paths, triggering an I/O failure with 'access beyond end of device'.
> With this patch the old paths are skipped from multipath path
> selection until the controller serving these paths has been rescanned.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> [dwagner: - introduce NVME_NS_READY flag instead of NVME_NS_INVALIDATE
>            - use 'revalidate' instead of 'invalidate' which
> 	    follows the zoned device code path.]
> Tested-by: Daniel Wagner <dwagner@suse.de>
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---
> v3:
>    - Renamed nvme_mpath_invalidated_paths to nvme_mpath_revalidate_paths()
>    - Replaced NVME_NS_INVALIDATE with NVME_NS_READY
> v2:
>    - https://lore.kernel.org/linux-nvme/20210730071059.124347-1-dwagner@suse.de/
>    - removed churn from failed rebase.
> v1:
>    - https://lore.kernel.org/linux-nvme/20210729194630.i5mhvvgb73duojqq@beryllium.lan/
> 
> drivers/nvme/host/core.c      |  3 +++
>   drivers/nvme/host/multipath.c | 17 ++++++++++++++++-
>   drivers/nvme/host/nvme.h      |  5 +++++
>   3 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 2f0cbaba12ac..54aafde4f556 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -1878,6 +1878,7 @@ static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_id_ns *id)
>   			goto out_unfreeze;
>   	}
>   
> +	set_bit(NVME_NS_READY, &ns->flags);
>   	blk_mq_unfreeze_queue(ns->disk->queue);
>   
>   	if (blk_queue_is_zoned(ns->queue)) {
> @@ -1889,6 +1890,7 @@ static int nvme_update_ns_info(struct nvme_ns *ns, struct nvme_id_ns *id)
>   	if (nvme_ns_head_multipath(ns->head)) {
>   		blk_mq_freeze_queue(ns->head->disk->queue);
>   		nvme_update_disk_info(ns->head->disk, ns, id);
> +		nvme_mpath_revalidate_paths(ns);
>   		blk_stack_limits(&ns->head->disk->queue->limits,
>   				 &ns->queue->limits, 0);
>   		blk_queue_update_readahead(ns->head->disk->queue);
> @@ -3816,6 +3818,7 @@ static void nvme_ns_remove(struct nvme_ns *ns)
>   	if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
>   		return;
>   
> +	clear_bit(NVME_NS_READY, &ns->flags);
>   	set_capacity(ns->disk, 0);
>   	nvme_fault_inject_fini(&ns->fault_inject);
>   
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 3f32c5e86bfc..d390f14b8bb6 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -147,6 +147,21 @@ void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
>   	mutex_unlock(&ctrl->scan_lock);
>   }
>   
> +void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
> +{
> +	struct nvme_ns_head *head = ns->head;
> +	sector_t capacity = get_capacity(head->disk);
> +	int node;
> +
> +	for_each_node(node)
> +		rcu_assign_pointer(head->current_path[node], NULL);
> +
> +	list_for_each_entry_rcu(ns, &head->list, siblings) {
> +		if (capacity != get_capacity(ns->disk))
> +			clear_bit(NVME_NS_READY, &ns->flags);
> +	}

Shouldn't the null setting to current_path come after
we clear NVME_NS_READY on the ns? Otherwise we may still
submit and current_path will be populated with the ns
again...

Re: [PATCH v3] nvme: revalidate paths during rescan

[Daniel Wagner]

On Mon, Aug 23, 2021 at 10:16:23AM -0700, Sagi Grimberg wrote:
> > +void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
> > +{
> > +	struct nvme_ns_head *head = ns->head;
> > +	sector_t capacity = get_capacity(head->disk);
> > +	int node;
> > +
> > +	for_each_node(node)
> > +		rcu_assign_pointer(head->current_path[node], NULL);
> > +
> > +	list_for_each_entry_rcu(ns, &head->list, siblings) {
> > +		if (capacity != get_capacity(ns->disk))
> > +			clear_bit(NVME_NS_READY, &ns->flags);
> > +	}
> 
> Shouldn't the null setting to current_path come after
> we clear NVME_NS_READY on the ns? Otherwise we may still
> submit and current_path will be populated with the ns
> again...

Ahh, I got it this time! Yes, you are right. I think Christoph has
dropped this patch from the nvme-5.15 queue anyway. I'll resend a new
version with the order changed.

Daniel

Re: [PATCH v3] nvme: revalidate paths during rescan

[Daniel Wagner]

On Tue, Aug 24, 2021 at 03:44:58PM +0200, Daniel Wagner wrote:
> On Mon, Aug 23, 2021 at 10:16:23AM -0700, Sagi Grimberg wrote:
> > > +void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
> > > +{
> > > +	struct nvme_ns_head *head = ns->head;
> > > +	sector_t capacity = get_capacity(head->disk);
> > > +	int node;
> > > +
> > > +	for_each_node(node)
> > > +		rcu_assign_pointer(head->current_path[node], NULL);
> > > +
> > > +	list_for_each_entry_rcu(ns, &head->list, siblings) {
> > > +		if (capacity != get_capacity(ns->disk))
> > > +			clear_bit(NVME_NS_READY, &ns->flags);
> > > +	}
> > 
> > Shouldn't the null setting to current_path come after
> > we clear NVME_NS_READY on the ns? Otherwise we may still
> > submit and current_path will be populated with the ns
> > again...
> 
> Ahh, I got it this time! Yes, you are right. I think Christoph has
> dropped this patch from the nvme-5.15 queue anyway. I'll resend a new
> version with the order changed.

I am blind. The patch is queued up in nvme-5.15.

@Christoph, do you want me to send fix on top of this patch or do you
want an updated version of this patch?

Re: [PATCH v3] nvme: revalidate paths during rescan

[Christoph Hellwig]

On Tue, Aug 24, 2021 at 03:48:30PM +0200, Daniel Wagner wrote:
> I am blind. The patch is queued up in nvme-5.15.
> 
> @Christoph, do you want me to send fix on top of this patch or do you
> want an updated version of this patch?

Either way is fine.