Command 10: OST_PUNCH
~~~~~~~~~~~~~~~~~~~~~
[[ost-punch-rpc]]

An RPC that modifies the size attribute of a resource on an OST.

.OST_PUNCH Generic Packet Structure
image::ost-punch-generic.png["OST_PUNCH Generic Packet Structure",height=100]

//////////////////////////////////////////////////////////////////////
The ost-punch-generic.png diagram resembles this text art:

       OST_PUNCH:
      --request-------------------------------
      | ptlrpc_body | ost_body | lustre_capa |
      ----------------------------------------
      --reply-------------------
      | ptlrpc_body | ost_body |
      --------------------------
//////////////////////////////////////////////////////////////////////

'ptlrpc_body'::
RPC descriptor.

'ost_body'::
Metadata about the resource, as it appears on the OST.

'lustre_capa'::
So called "capabilities" structure. This is deprecated in recent
versions of Lustre, and commonly appears in the packet header as a zero
length buffer.