[PATCH V2 3/4] nvmet: allow readonly bdev-ns to be configured

[Chaitanya Kulkarni]

Right now we open bdev-ns in read-write mode. This doesn't allow us to
export the bdev which is marked read-only using blockdev --setro.

Allow user to export the readonly bdev by considering the
ns->write_protect configfs attribute when opening the bdev. Use
FMODE_WRITE when ns->write_protect is not set.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
---
 drivers/nvme/target/io-cmd-bdev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index 125dde3f410e..0e6b5312ad1e 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -65,10 +65,10 @@ static void nvmet_bdev_ns_enable_integrity(struct nvmet_ns *ns)
 
 int nvmet_bdev_ns_enable(struct nvmet_ns *ns)
 {
+	fmode_t mode = (ns->write_protect ? 0 : FMODE_WRITE) | FMODE_READ;
 	int ret;
 
-	ns->bdev = blkdev_get_by_path(ns->device_path,
-			FMODE_READ | FMODE_WRITE, NULL);
+	ns->bdev = blkdev_get_by_path(ns->device_path, mode, NULL);
 	if (IS_ERR(ns->bdev)) {
 		ret = PTR_ERR(ns->bdev);
 		if (ret != -ENOTBLK) {
-- 
2.22.1