MDEV-17601: MariaDB Galera does not expect 'mbstream' as streamfmt

Setting "streamfmt=mbstream" in the "[sst]" section causes SST to fail
because the format automatically switches to 'tar' by default (insead
of mbstream).

To fix this, we need to add mbstream to the list of valid values for
the format, making it synonymous with xbstream. This must be done both
in the SST script and when parsing the options of the corresponding
utilities.

extra/mariabackup/CMakeLists.txt

@@ -94,7 +94,7 @@ ENDIF()
 
 
 ########################################################################
-# xbstream binary
+# mbstream binary
 ########################################################################
 MYSQL_ADD_EXECUTABLE(mbstream
   ds_buffer.c

extra/mariabackup/innobackupex.cc

@@ -600,8 +600,8 @@ static struct my_option ibx_long_options[] =
 	{"stream", OPT_STREAM, "This option specifies the format in which to "
 	 "do the streamed backup.  The option accepts a string argument. The "
 	 "backup will be done to STDOUT in the specified format. Currently, "
-	 "the only supported formats are tar and xbstream. This option is "
-	 "passed directly to xtrabackup's --stream option.",
+	 "the only supported formats are tar and mbstream/xbstream. This "
+	 "option is passed directly to xtrabackup's --stream option.",
 	 (uchar*) &ibx_xtrabackup_stream_str,
 	 (uchar*) &ibx_xtrabackup_stream_str, 0, GET_STR,
 	 REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
@@ -669,7 +669,7 @@ innobackupex [--compress] [--compress-threads=NUMBER-OF-THREADS] [--compress-chu
              [--include=REGEXP] [--user=NAME]\n\
              [--password=WORD] [--port=PORT] [--socket=SOCKET]\n\
              [--no-timestamp] [--ibbackup=IBBACKUP-BINARY]\n\
-             [--slave-info] [--galera-info] [--stream=tar|xbstream]\n\
+             [--slave-info] [--galera-info] [--stream=tar|mbstream|xbstream]\n\
              [--defaults-file=MY.CNF] [--defaults-group=GROUP-NAME]\n\
              [--databases=LIST] [--no-lock] \n\
              [--tmpdir=DIRECTORY] [--tables-file=FILE]\n\
@@ -765,7 +765,8 @@ ibx_get_one_option(int optid,
 		}
 		break;
 	case OPT_STREAM:
-    if (!strcasecmp(argument, "xbstream"))
+		if (!strcasecmp(argument, "mbstream") ||
+		    !strcasecmp(argument, "xbstream"))
 			xtrabackup_stream_fmt = XB_STREAM_FMT_XBSTREAM;
 		else {
 			ibx_msg("Invalid --stream argument: %s\n", argument);

extra/mariabackup/xtrabackup.cc

@@ -675,7 +675,7 @@ struct my_option xb_client_options[] =
 
   {"stream", OPT_XTRA_STREAM, "Stream all backup files to the standard output "
    "in the specified format." 
-   "Supported format is 'xbstream'."
+   "Supported format is 'mbstream' or 'xbstream'."
    ,
    (G_PTR*) &xtrabackup_stream_str, (G_PTR*) &xtrabackup_stream_str, 0, GET_STR,
    REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
@@ -1398,7 +1398,8 @@ xb_get_one_option(int optid,
     xtrabackup_target_dir= xtrabackup_real_target_dir;
     break;
   case OPT_XTRA_STREAM:
-    if (!strcasecmp(argument, "xbstream"))
+    if (!strcasecmp(argument, "mbstream") ||
+        !strcasecmp(argument, "xbstream"))
       xtrabackup_stream_fmt = XB_STREAM_FMT_XBSTREAM;
     else
     {

scripts/wsrep_sst_mariabackup.sh

@@ -386,8 +386,8 @@ read_cnf()
 
 get_stream()
 {
-    if [[ $sfmt == 'xbstream' ]];then 
-        wsrep_log_info "Streaming with xbstream"
+    if [[ $sfmt == 'mbstream' || $sfmt == 'xbstream' ]];then
+        wsrep_log_info "Streaming with ${sfmt}"
         if [[ "$WSREP_SST_OPT_ROLE"  == "joiner" ]];then
             strmcmd="${XBSTREAM_BIN} -x"
         else