From: Christoph Hellwig <hch@lst.de>
Date: Thu, 17 Aug 2017 14:10:00 +0200
Subject: nvme: don't blindly overwrite identifiers on disk revalidate
Patch-mainline: v4.14-rc1
Git-commit: 1d5df6af8c7469f9ae3e66e7bed0782cfe4f95db
References: FATE#323952, FATE#322506

Instead validate that these identifiers do not change, as that is
prohibited by the specification.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/nvme/host/core.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1243,6 +1243,8 @@ static int nvme_revalidate_disk(struct g
 	struct nvme_ns *ns = disk->private_data;
 	struct nvme_ctrl *ctrl = ns->ctrl;
 	struct nvme_id_ns *id;
+	u8 eui64[8] = { 0 }, nguid[16] = { 0 };
+	uuid_t uuid = uuid_null;
 	int ret = 0;
 
 	if (test_bit(NVME_NS_DEAD, &ns->flags)) {
@@ -1259,7 +1261,15 @@ static int nvme_revalidate_disk(struct g
 		goto out;
 	}
 
-	nvme_report_ns_ids(ctrl, ns->ns_id, id, ns->eui, ns->nguid, &ns->uuid);
+	nvme_report_ns_ids(ctrl, ns->ns_id, id, eui64, nguid, &uuid);
+	if (!uuid_equal(&ns->uuid, &uuid) ||
+	    memcmp(&ns->nguid, &nguid, sizeof(ns->nguid)) ||
+	    memcmp(&ns->eui, &eui64, sizeof(ns->eui))) {
+		dev_err(ctrl->device,
+			"identifiers changed for nsid %d\n", ns->ns_id);
+		ret = -ENODEV;
+	}
+
 out:
 	kfree(id);
 	return ret;