CIFS: Add SMB2 support for build_path_to_root

Signed-off-by: NPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

fs/cifs/smb2ops.c

@@ -190,6 +190,23 @@ smb2_get_srv_inum(const unsigned int xid, struct cifs_tcon *tcon,
 	return 0;
 }
 
+static char *
+smb2_build_path_to_root(struct smb_vol *vol, struct cifs_sb_info *cifs_sb,
+			struct cifs_tcon *tcon)
+{
+	int pplen = vol->prepath ? strlen(vol->prepath) : 0;
+	char *full_path = NULL;
+
+	/* if no prefix path, simply set path to the root of share to "" */
+	if (pplen == 0) {
+		full_path = kzalloc(2, GFP_KERNEL);
+		return full_path;
+	}
+
+	cERROR(1, "prefixpath is not supported for SMB2 now");
+	return NULL;
+}
+
 struct smb_version_operations smb21_operations = {
 	.setup_request = smb2_setup_request,
 	.check_receive = smb2_check_receive,
@@ -210,6 +227,7 @@ struct smb_version_operations smb21_operations = {
 	.is_path_accessible = smb2_is_path_accessible,
 	.query_path_info = smb2_query_path_info,
 	.get_srv_inum = smb2_get_srv_inum,
+	.build_path_to_root = smb2_build_path_to_root,
 };
 
 struct smb_version_values smb21_values = {