ksmbd: call putname after using the last component

commit 6fe55c2 upstream.

last component point filename struct. Currently putname is called after
vfs_path_parent_lookup(). And then last component is used for
lookup_one_qstr_excl(). name in last component is freed by previous
calling putname(). And It cause file lookup failure when testing
generic/464 test of xfstest.

Fixes: 74d7970 ("ksmbd: fix racy issue from using ->d_parent and ->d_name")
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ksmbd/vfs.c

@@ -86,12 +86,14 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf,
 	err = vfs_path_parent_lookup(filename, flags,
 				     &parent_path, &last, &type,
 				     root_share_path);
-	putname(filename);
-	if (err)
+	if (err) {
+		putname(filename);
 		return err;
+	}
 
 	if (unlikely(type != LAST_NORM)) {
 		path_put(&parent_path);
+		putname(filename);
 		return -ENOENT;
 	}
 
@@ -108,12 +110,14 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf,
 	path->dentry = d;
 	path->mnt = share_conf->vfs_path.mnt;
 	path_put(&parent_path);
+	putname(filename);
 
 	return 0;
 
 err_out:
 	inode_unlock(parent_path.dentry->d_inode);
 	path_put(&parent_path);
+	putname(filename);
 	return -ENOENT;
 }