cifs: cifs_inval_name_dfs_link_error: correct the check for fullpath

Replace the always-true check tcon->origin_fullpath with
check of server->leaf_fullpath

See https://bugzilla.kernel.org/show_bug.cgi?id=219083

The check of the new @tcon will always be true during mounting,
since @tcon->origin_fullpath will only be set after the tree is
connected to the latest common resource, as well as checking if
the prefix paths from it are fully accessible.

Fixes: 3ae872de ("smb: client: fix shared DFS root mounts with different prefixes")
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Gleb Korobeynikov <gkorobeynikov@astralinux.ru>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/misc.c

@@ -1234,6 +1234,7 @@ int cifs_inval_name_dfs_link_error(const unsigned int xid,
 				   const char *full_path,
 				   bool *islink)
 {
+	struct TCP_Server_Info *server = tcon->ses->server;
 	struct cifs_ses *ses = tcon->ses;
 	size_t len;
 	char *path;
@@ -1250,12 +1251,12 @@ int cifs_inval_name_dfs_link_error(const unsigned int xid,
 	    !is_tcon_dfs(tcon))
 		return 0;
 
-	spin_lock(&tcon->tc_lock);
-	if (!tcon->origin_fullpath) {
-		spin_unlock(&tcon->tc_lock);
+	spin_lock(&server->srv_lock);
+	if (!server->leaf_fullpath) {
+		spin_unlock(&server->srv_lock);
 		return 0;
 	}
-	spin_unlock(&tcon->tc_lock);
+	spin_unlock(&server->srv_lock);
 
 	/*
 	 * Slow path - tcon is DFS and @full_path has prefix path, so attempt