[PATCH 2/2] nvme-multipath: retry partition scan on errors

[Hannes Reinecke <hare@kernel.org>]

When we hit I/O errors during partition scan we can assume that
partition scanning was incomplete. Rather than continue to work
with an incomplete device we should disable the disk completely,
and wait for a rescan to retry again.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 drivers/nvme/host/multipath.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 68eb1df98419..f70952c6d683 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -243,6 +243,21 @@ void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
 	kblockd_schedule_work(&head->requeue_work);
 }
 
+static bool nvme_scan_errors(struct nvme_ns_head *head)
+{
+	int srcu_idx, valid = 0;
+	struct nvme_ns *ns;
+
+	srcu_idx = srcu_read_lock(&head->srcu);
+	list_for_each_entry_rcu(ns, &head->list, siblings) {
+		if (!test_bit(NVME_NS_SCAN_FAILED, &ns->flags))
+			valid++;
+	}
+	srcu_read_unlock(&head->srcu, srcu_idx);
+
+	return !valid;
+}
+
 static bool nvme_path_is_disabled(struct nvme_ns *ns)
 {
 	enum nvme_ctrl_state state = nvme_ctrl_state(ns->ctrl);
@@ -670,6 +685,11 @@ static void nvme_mpath_set_live(struct nvme_ns *ns)
 			clear_bit(NVME_NSHEAD_DISK_LIVE, &head->flags);
 			return;
 		}
+		if (nvme_scan_errors(head)) {
+			del_gendisk(head->disk);
+			clear_bit(NVME_NSHEAD_DISK_LIVE, &head->flags);
+			return;
+		}
 		nvme_add_ns_head_cdev(head);
 	}
 
-- 
2.35.3