MDEV-38562: mariabackup exits with success (0) despite "No space left on device" errors

extra/mariabackup/ds_local.cc

@@ -264,7 +264,9 @@ local_close(ds_file_t *file)
 		ret = set_eof(fd);
 	}
 
-	my_close(fd, MYF(MY_WME));
+	if (my_close(fd, MYF(MY_WME)) != 0)
+	  ret= 1;
+
 	my_free(file);
 	return ret;
 }

mysql-test/suite/mariabackup/error_during_copyback.result

@@ -8,3 +8,12 @@ SELECT * FROM t;
 i
 1
 DROP TABLE t;
+#
+# MDEV-38562: mariabackup exits with success (0) despite "No space left on device" errors
+#
+# Simulate close() failure (Disk Full / ENOSPC)
+# Verify that "completed OK!" is NOT in the log
+NOT FOUND /completed OK!/ in backup.log
+# Verify that "FATAL ERROR" is in the log
+FOUND 1 /FATAL ERROR/ in backup.log
+# End of 10.6 tests

mysql-test/suite/mariabackup/error_during_copyback.test

@@ -23,3 +23,27 @@ SELECT * FROM t;
 DROP TABLE t;
 rmdir $targetdir;
 
+--echo #
+--echo # MDEV-38562: mariabackup exits with success (0) despite "No space left on device" errors
+--echo #
+
+--let $targetdir=$MYSQLTEST_VARDIR/tmp/backup
+
+--echo # Simulate close() failure (Disk Full / ENOSPC)
+--error 1
+--exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir --dbug=+d,my_close_fail >$MYSQLTEST_VARDIR/tmp/backup.log 2>&1
+
+--echo # Verify that "completed OK!" is NOT in the log
+--let SEARCH_FILE=$MYSQLTEST_VARDIR/tmp/backup.log
+--let SEARCH_PATTERN=completed OK!
+--source include/search_pattern_in_file.inc
+
+--echo # Verify that "FATAL ERROR" is in the log
+--let SEARCH_FILE=$MYSQLTEST_VARDIR/tmp/backup.log
+--let SEARCH_PATTERN=FATAL ERROR
+--source include/search_pattern_in_file.inc
+
+--remove_file $MYSQLTEST_VARDIR/tmp/backup.log
+rmdir $targetdir;
+
+--echo # End of 10.6 tests

mysys/my_open.c

@@ -94,6 +94,9 @@ int my_close(File fd, myf MyFlags)
 #else
   err= my_win_close(fd);
 #endif
+
+  DBUG_EXECUTE_IF("my_close_fail", { errno=28; err=-1; });
+
   if (err)
   {
     DBUG_PRINT("error",("Got error %d on close",err));