diff --git a/fs/block_dev.c b/fs/block_dev.c
index 19f5f15..846f32d 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -920,7 +920,7 @@
 	}
 	owner = disk->fops->owner;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock_nested(&bdev->bd_mutex, for_part);
 	if (!bdev->bd_openers) {
 		bdev->bd_disk = disk;
 		bdev->bd_contains = bdev;
@@ -1062,7 +1062,7 @@
 	struct gendisk *disk = bdev->bd_disk;
 	struct block_device *victim = NULL;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock_nested(&bdev->bd_mutex, for_part);
 	lock_kernel();
 	if (for_part)
 		bdev->bd_part_count--;