LUDOC-276 protocol: Document RPCs for setattr

[doc/protocol.git] / mds_reint.txt

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+Command 36: MDS_REINT
+~~~~~~~~~~~~~~~~~~~~~
+[[mds-reint-rpm]]
+
+An RPC that implements an operation that will change the information
+on an MDT.
+
+REINT_SETATTR
+^^^^^^^^^^^^^
+[[mds-reint-setattr-rpc]]
+
+An RPC that implements the 'setattr' sub-command of the MDS_REINT.
+
+.MDS_REINT:REINT_SETATTR Generic Packet Structure
+image::mds-reint-setattr-generic.png["MDS_REINT:REINT_SETATTR Generic Packet Structure",height=100]
+
+//////////////////////////////////////////////////////////////////////
+The mds-reint-setattr-generic.png diagram resembles this text art:
+
+        MDS_REINT:
+      --REINT_SETATTR-request-------------------------------------
+      | ptlrpc_body | mdt_rec_setattr | lustre_capa | mdt_ioepoc |
+        eadata | llog_cookie | ldlm_request |
+      ------------------------------------------------------------
+
+      --REINT_SETATTR-reply----------------------------------
+      | ptlrpc_body | mdt_body | mdt_md | acl | lustre_capa |
+        lustre_capa |
+      -------------------------------------------------------
+//////////////////////////////////////////////////////////////////////
+
+'ptlrpc_body'::
+RPC descriptor.
+
+'mdt_rec_setattr'::
+Information pertinent to setting attributes on the MDT.
+
+'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.
+
+'mdt_ioepoch'::
+Identifying "epoch" information. This buffer is optional and will
+appear as zero length in some packets.
+
+'eadata'::
+Information about extended attributes. This buffer is optional and will
+appear as zero length in some packets.
+
+'llog_cookie'::
+A log handle.  This buffer is optional and will appear as zero length
+in some packets.
+
+'ldlm_request'::
+A structure specifying a lock that can be the subject of early lock
+cancellation. See <<early-lock-cancellation>>.
+
+'mdt_body'::
+Metadata about the resource.
+
+'mdt_md'::
+Layout data for the resource. This buffer is optional and will appear
+as zero length in some packets.
+
+'acl'::
+Access control list data. This buffer is optional and will appear as
+zero length in some packets.
+