fs: use block_device name vsprintf helper

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 24154e4..a0434c17 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1514,9 +1514,7 @@
 		if ((flags ^ s->s_flags) & MS_RDONLY)
 			error = -EBUSY;
 	} else {
-		char b[BDEVNAME_SIZE];
-
-		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
+		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
 		btrfs_sb(s)->bdev_holder = fs_type;
 		error = btrfs_fill_super(s, fs_devices, data,
 					 flags & MS_SILENT ? 1 : 0);