[PATCH 1/2] nvmet: make 'readonly' setting configurable

[Hannes Reinecke <hare@kernel.org>]

The namespace already has a 'readonly' setting, which is controlled
by the 'write protect' feature. This patch introduces a namespace
configfs attribute 'readonly' to make it settable by the admin.

Suggested-by: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 drivers/nvme/target/configfs.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 00fd6ab046dd..cb03b448ae6d 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -820,6 +820,32 @@ static ssize_t nvmet_ns_resv_enable_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_ns_, resv_enable);
 
+static ssize_t nvmet_ns_readonly_show(struct config_item *item, char *page)
+{
+	return sysfs_emit(page, "%d\n", to_nvmet_ns(item)->readonly);
+}
+
+static ssize_t nvmet_ns_readonly_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct nvmet_ns *ns = to_nvmet_ns(item);
+	bool val;
+
+	if (kstrtobool(page, &val))
+		return -EINVAL;
+
+	mutex_lock(&ns->subsys->lock);
+	if (ns->enabled) {
+		pr_err("the ns:%d is already enabled.\n", ns->nsid);
+		mutex_unlock(&ns->subsys->lock);
+		return -EINVAL;
+	}
+	ns->readonly = val;
+	mutex_unlock(&ns->subsys->lock);
+	return count;
+}
+CONFIGFS_ATTR(nvmet_ns_, readonly);
+
 static struct configfs_attribute *nvmet_ns_attrs[] = {
 	&nvmet_ns_attr_device_path,
 	&nvmet_ns_attr_device_nguid,
@@ -830,6 +856,7 @@ static struct configfs_attribute *nvmet_ns_attrs[] = {
 	&nvmet_ns_attr_buffered_io,
 	&nvmet_ns_attr_revalidate_size,
 	&nvmet_ns_attr_resv_enable,
+	&nvmet_ns_attr_readonly,
 #ifdef CONFIG_PCI_P2PDMA
 	&nvmet_ns_attr_p2pmem,
 #endif
-- 
2.35.3