static int namespace_update_uuid()

in namespace_devs.c [1182:1250]

• 48 lines of code
• 10 McCabe index (conditional complexity)

static int namespace_update_uuid(struct nd_region *nd_region,
				 struct device *dev, uuid_t *new_uuid,
				 uuid_t **old_uuid)
{
	u32 flags = is_namespace_blk(dev) ? NSLABEL_FLAG_LOCAL : 0;
	struct nd_label_id old_label_id;
	struct nd_label_id new_label_id;
	int i;

	if (!nd_is_uuid_unique(dev, new_uuid))
		return -EINVAL;

	if (*old_uuid == NULL)
		goto out;

	/*
	 * If we've already written a label with this uuid, then it's
	 * too late to rename because we can't reliably update the uuid
	 * without losing the old namespace.  Userspace must delete this
	 * namespace to abandon the old uuid.
	 */
	for (i = 0; i < nd_region->ndr_mappings; i++) {
		struct nd_mapping *nd_mapping = &nd_region->mapping[i];

		/*
		 * This check by itself is sufficient because old_uuid
		 * would be NULL above if this uuid did not exist in the
		 * currently written set.
		 *
		 * FIXME: can we delete uuid with zero dpa allocated?
		 */
		if (list_empty(&nd_mapping->labels))
			return -EBUSY;
	}

	nd_label_gen_id(&old_label_id, *old_uuid, flags);
	nd_label_gen_id(&new_label_id, new_uuid, flags);
	for (i = 0; i < nd_region->ndr_mappings; i++) {
		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
		struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
		struct nd_label_ent *label_ent;
		struct resource *res;

		for_each_dpa_resource(ndd, res)
			if (strcmp(res->name, old_label_id.id) == 0)
				sprintf((void *) res->name, "%s",
						new_label_id.id);

		mutex_lock(&nd_mapping->lock);
		list_for_each_entry(label_ent, &nd_mapping->labels, list) {
			struct nd_namespace_label *nd_label = label_ent->label;
			struct nd_label_id label_id;
			uuid_t uuid;

			if (!nd_label)
				continue;
			nsl_get_uuid(ndd, nd_label, &uuid);
			nd_label_gen_id(&label_id, &uuid,
					nsl_get_flags(ndd, nd_label));
			if (strcmp(old_label_id.id, label_id.id) == 0)
				set_bit(ND_LABEL_REAP, &label_ent->flags);
		}
		mutex_unlock(&nd_mapping->lock);
	}
	kfree(*old_uuid);
 out:
	*old_uuid = new_uuid;
	return 0;
}