ext4: fix possible double unlock when moving a directory

Fixes: 0813299 ("ext4: Fix possible corruption when moving a directory")
Link: https://lore.kernel.org/r/5efbe1b9-ad8b-4a4f-b422-24824d2b775c@kili.mountain
Reported-by: Dan Carpenter <error27@gmail.com>
Reported-by: syzbot+0c73d1d8b952c5f3d714@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/namei.c

@@ -3884,10 +3884,8 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 				goto end_rename;
 		}
 		retval = ext4_rename_dir_prepare(handle, &old);
-		if (retval) {
-			inode_unlock(old.inode);
+		if (retval)
 			goto end_rename;
-		}
 	}
 	/*
 	 * If we're renaming a file within an inline_data dir and adding or