[PATCH v4] nvme-multipath: revalidate paths during rescan

From: Daniel Wagner
Date: Tue Aug 24 2021 - 10:57:51 EST


From: Hannes Reinecke <hare@xxxxxxx>

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@xxxxxxx>
[dwagner: - introduce NVME_NS_READY flag instead of NVME_NS_INVALIDATE
- use 'revalidate' instead of 'invalidate' which
follows the zoned device code path.
- clear NVME_NS_READY before clearing current_path]
Tested-by: Daniel Wagner <dwagner@xxxxxxx>
Signed-off-by: Daniel Wagner <dwagner@xxxxxxx>
---
v3:
- https://lore.kernel.org/linux-nvme/20210811152803.30017-1-dwagner@xxxxxxx/
- 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@xxxxxxx/
- removed churn from failed rebase.
v1:
- https://lore.kernel.org/linux-nvme/20210729194630.i5mhvvgb73duojqq@xxxxxxxxxxxxx/


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 b9a46c54f714..42b69f3c6e20 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1875,6 +1875,7 @@ 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)) {
@@ -1886,6 +1887,7 @@ 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);
@@ -3803,6 +3805,7 @@ 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..ea2b70fd9ac1 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;
+
+ list_for_each_entry_rcu(ns, &head->list, siblings) {
+ if (capacity != get_capacity(ns->disk))
+ clear_bit(NVME_NS_READY, &ns->flags);
+ }
+
+ for_each_node(node)
+ rcu_assign_pointer(head->current_path[node], NULL);
+}
+
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 a2e1f298b217..8fd30ef19757 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -456,6 +456,7 @@ 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;
@@ -748,6 +749,7 @@ 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);

@@ -795,6 +797,9 @@ 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