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.
MariaDB · Jun 10, 2020 · ae3a7d5 · ae3a7d5
1 parent 59717bb
commit ae3a7d5
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Showing 2 changed files with 10 additions and 9 deletions.
diff --git a/plugin/disks/information_schema_disks.cc b/plugin/disks/information_schema_disks.cc
@@ -32,9 +32,9 @@ ST_FIELD_INFO disks_table_fields[]=
 {
     { "Disk",      PATH_MAX, MYSQL_TYPE_STRING, 0, 0 ,0, 0 },
     { "Path",      PATH_MAX, MYSQL_TYPE_STRING, 0, 0 ,0, 0 },
-    { "Total",           32, MYSQL_TYPE_LONG,   0, 0 ,0 ,0 }, // Total amount available
-    { "Used",            32, MYSQL_TYPE_LONG,   0, 0 ,0 ,0 }, // Amount of space used
-    { "Available",       32, MYSQL_TYPE_LONG,   0, 0 ,0 ,0 }, // Amount available to users other than root.
+    { "Total",           32, MYSQL_TYPE_LONGLONG,   0, 0 ,0 ,0 }, // Total amount available
+    { "Used",            32, MYSQL_TYPE_LONGLONG,   0, 0 ,0 ,0 }, // Amount of space used
+    { "Available",       32, MYSQL_TYPE_LONGLONG,   0, 0 ,0 ,0 }, // Amount available to users other than root.
     { 0, 0, MYSQL_TYPE_NULL, 0, 0, 0, 0 }
 };
 
@@ -51,9 +51,10 @@ 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);

diff --git a/plugin/disks/mysql-test/disks/disks.result b/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)