Btrfs: btrfs_iget() returns ERR_PTR

btrfs_iget() returns an ERR_PTR() on failure and not null.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs/btrfs/super.c

@@ -392,8 +392,8 @@ static struct dentry *get_default_root(struct super_block *sb,
 	location.offset = 0;
 
 	inode = btrfs_iget(sb, &location, new_root, &new);
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
 
 	/*
 	 * If we're just mounting the root most subvol put the inode and return