MDEV-22834: Disks plugin - change datatype to bigint

On large hard disks (> 2TB), the plugin won't function correctly, always
showing 2 TB of available space due to integer overflow. Upgrade table
fields to bigint to resolve this problem.

plugin/disks/information_schema_disks.cc

@@ -34,9 +34,9 @@ ST_FIELD_INFO disks_table_fields[]=
 {
   Column("Disk",      Varchar(PATH_MAX), NOT_NULL),
   Column("Path",      Varchar(PATH_MAX), NOT_NULL),
-  Column("Total",     SLong(32),         NOT_NULL), // Total amount available
-  Column("Used",      SLong(32),         NOT_NULL), // Amount of space used
-  Column("Available", SLong(32),         NOT_NULL), // Amount available to users other than root.
+  Column("Total",     SLonglong(32),     NOT_NULL), // Total amount available
+  Column("Used",      SLonglong(32),     NOT_NULL), // Amount of space used
+  Column("Available", SLonglong(32),     NOT_NULL), // Amount available to users other than root.
   CEnd()
 };
 
@@ -55,9 +55,10 @@ int disks_table_add_row(THD* pThd,
     // f_bfree    Total number of free blocks.
     // f_bavail   Number of free blocks available to non-privileged process.
 
-    size_t total = (info.f_frsize * info.f_blocks) / 1024;
-    size_t used  = (info.f_frsize * (info.f_blocks - info.f_bfree)) / 1024;
-    size_t avail = (info.f_frsize * info.f_bavail) / 1024;
+    ulonglong total = ((ulonglong)info.f_frsize * info.f_blocks) / 1024;
+    ulonglong used  = ((ulonglong)info.f_frsize *
+                            (info.f_blocks - info.f_bfree)) / 1024;
+    ulonglong avail = ((ulonglong)info.f_frsize * info.f_bavail) / 1024;
 
     pTable->field[0]->store(zDisk, strlen(zDisk), system_charset_info);
     pTable->field[1]->store(zPath, strlen(zPath), system_charset_info);

plugin/disks/mysql-test/disks/disks.result

@@ -3,9 +3,9 @@ Table	Create Table
 DISKS	CREATE TEMPORARY TABLE `DISKS` (
   `Disk` varchar(4096) NOT NULL DEFAULT '',
   `Path` varchar(4096) NOT NULL DEFAULT '',
-  `Total` int(32) NOT NULL DEFAULT 0,
-  `Used` int(32) NOT NULL DEFAULT 0,
-  `Available` int(32) NOT NULL DEFAULT 0
+  `Total` bigint(32) NOT NULL DEFAULT 0,
+  `Used` bigint(32) NOT NULL DEFAULT 0,
+  `Available` bigint(32) NOT NULL DEFAULT 0
 ) ENGINE=MEMORY DEFAULT CHARSET=utf8
 select sum(Total) > sum(Available), sum(Total)>sum(Used) from information_schema.disks;
 sum(Total) > sum(Available)	sum(Total)>sum(Used)