btrfs: dev add should add its sysfs entry

we would need the device links to be created,
when device is added.

Signed-off-by: Anand Jain <Anand.Jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index be2c8e2..19b67e9 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2147,6 +2147,10 @@
 	total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
 	btrfs_set_super_num_devices(root->fs_info->super_copy,
 				    total_bytes + 1);
+
+	/* add sysfs device entry */
+	btrfs_kobj_add_device(root->fs_info, device);
+
 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
 	if (seeding_dev) {
@@ -2209,6 +2213,7 @@
 	unlock_chunks(root);
 	btrfs_end_transaction(trans, root);
 	rcu_string_free(device->name);
+	btrfs_kobj_rm_device(root->fs_info, device);
 	kfree(device);
 error:
 	blkdev_put(bdev, FMODE_EXCL);