cifs: don't call cifs_dfs_query_info_nonascii_quirk() if nodfs was set

Also return EOPNOTSUPP if path is remote but nodfs was set.

Fixes: a2809d0e ("cifs: quirk for STATUS_OBJECT_NAME_INVALID returned for non-ASCII dfs refs")
Cc: stable@vger.kernel.org
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/connect.c

@@ -3432,6 +3432,7 @@ static int is_path_remote(struct mount_ctx *mnt_ctx)
 	struct cifs_tcon *tcon = mnt_ctx->tcon;
 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
 	char *full_path;
+	bool nodfs = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS;
 
 	if (!server->ops->is_path_accessible)
 		return -EOPNOTSUPP;
@@ -3449,14 +3450,20 @@ static int is_path_remote(struct mount_ctx *mnt_ctx)
 	rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
 					     full_path);
 #ifdef CONFIG_CIFS_DFS_UPCALL
+	if (nodfs) {
+		if (rc == -EREMOTE)
+			rc = -EOPNOTSUPP;
+		goto out;
+	}
+
+	/* path *might* exist with non-ASCII characters in DFS root
+	 * try again with full path (only if nodfs is not set) */
 	if (rc == -ENOENT && is_tcon_dfs(tcon))
 		rc = cifs_dfs_query_info_nonascii_quirk(xid, tcon, cifs_sb,
 							full_path);
 #endif
-	if (rc != 0 && rc != -EREMOTE) {
-		kfree(full_path);
-		return rc;
-	}
+	if (rc != 0 && rc != -EREMOTE)
+		goto out;
 
 	if (rc != -EREMOTE) {
 		rc = cifs_are_all_path_components_accessible(server, xid, tcon,
@@ -3468,6 +3475,7 @@ static int is_path_remote(struct mount_ctx *mnt_ctx)
 		}
 	}
 
+out:
 	kfree(full_path);
 	return rc;
 }