audit_get_nd(): don't unlock parent too early

[ Upstream commit 69924b89687a2923e88cc42144aea27868913d0e ]

if the child has been negative and just went positive
under us, we want coherent d_is_positive() and ->d_inode.
Don't unlock the parent until we'd done that work...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NSasha Levin <sashal@kernel.org>

kernel/audit_watch.c

@@ -366,12 +366,12 @@ static int audit_get_nd(struct audit_watch *watch, struct path *parent)
 	struct dentry *d = kern_path_locked(watch->path, parent);
 	if (IS_ERR(d))
 		return PTR_ERR(d);
-	inode_unlock(d_backing_inode(parent->dentry));
 	if (d_is_positive(d)) {
 		/* update watch filter fields */
 		watch->dev = d->d_sb->s_dev;
 		watch->ino = d_backing_inode(d)->i_ino;
 	}
+	inode_unlock(d_backing_inode(parent->dentry));
 	dput(d);
 	return 0;
 }