This patch fixes an issue where snmpdf was not returning the 

correct total disk size and available disk size when the size 

of the filesystem is larger than 1TB.This bug is already fixed 

in the community and the fix is available from the net-snmp 

version 5.6 onwards.The fix here slightly differs from the community 

since the patch in the community is applied on net-snmp version 5.6 .

This patch is taken from the below link.

https://bugs.launchpad.net/ubuntu/+source/net-snmp/+bug/865268

--- net-snmp-5.4.1/agent/mibgroup/host/hr_storage.c	Thu May 21 23:47:45 2015

+++ net-snmp-5.4.1/agent/mibgroup/host/hr_storage.c	Thu May 21 23:55:59 2015

@@ -505,6 +505,7 @@

             int exact, size_t * var_len, WriteMethod ** write_method)

 {

     int             store_idx = 0;

+    int             factor = 0;

     static char     string[1024];

     struct HRFS_statfs stat_buf;

     void                *ptr;

@@ -558,6 +558,12 @@

 	    mem = (netsnmp_memory_info*)ptr;

         }

+/* Scaling factor for large filesystems */

+    if (store_idx > NETSNMP_MEM_TYPE_MAX) {

+        unsigned long long tmp = stat_buf.f_blocks;

+        while (tmp > 0x7fffffff)

+            tmp >>= 1, factor++;

+    }

     switch (vp->magic) {

@@ -593,9 +599,9 @@

     case HRSTORE_UNITS:

         if (store_idx > NETSNMP_MEM_TYPE_MAX)

 #if HRFS_HAS_FRSIZE

-            long_return = stat_buf.f_frsize;

+            long_return = stat_buf.f_frsize << factor;

 #else

-            long_return = stat_buf.f_bsize;

+            long_return = stat_buf.f_bsize << factor;

 #endif

         else {

             if ( !mem || mem->units == -1 )

@@ -605,7 +611,7 @@

         return (u_char *) & long_return;

     case HRSTORE_SIZE:

         if (store_idx > NETSNMP_MEM_TYPE_MAX)

-            long_return = stat_buf.f_blocks;

+            long_return = stat_buf.f_blocks >> factor;

         else {

             if ( !mem || mem->size == -1 )

                 goto try_next;

@@ -614,7 +620,7 @@

         return (u_char *) & long_return;

     case HRSTORE_USED:

         if (store_idx > NETSNMP_MEM_TYPE_MAX)

-            long_return = (stat_buf.f_blocks - stat_buf.f_bfree);

+            long_return = (stat_buf.f_blocks - stat_buf.f_bfree) >> factor;

         else {

             if ( !mem || mem->size == -1 || mem->free == -1 )

                 goto try_next;