Command 36: MDS_REINT
~~~~~~~~~~~~~~~~~~~~~
[[mds-reint-rpm]]

An RPC that implements an operation that will change the information
on an MDT. There are a variety of operations all gathered under the
MDS_REINT 'opcode'.

----
typedef enum {
	REINT_SETATTR  = 1,
	REINT_CREATE   = 2,
	REINT_LINK     = 3,
	REINT_UNLINK   = 4,
	REINT_RENAME   = 5,
	REINT_OPEN     = 6,
	REINT_SETXATTR = 7,
	REINT_RMENTRY  = 8,
	REINT_MIGRATE  = 9,
        REINT_MAX
} mds_reint_t, mdt_reint_t;
----

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 |
      -------------------------------------------------------
//////////////////////////////////////////////////////////////////////

The second buffer ('mdt_rec_setattr' in the above) is one of the
variants specific to the particular REINT as given by the
'mdt_reint_t' opcode. Each such variant has the same number and size
of fields, but how the fields are interpreted varies slightly between
variiants. For all the variant structures refer to
<<mds-reint-structs>>.

REINT_SETXATTR
^^^^^^^^^^^^^^
[[mds-reint-setxattr-rpc]]

An RPC that implements the 'setxattr' sub-command of the MDS_REINT.

.MDS_REINT:REINT_SETXATTR Generic Packet Structure
image::mds-reint-setxattr-generic.png["MDS_REINT:REINT_SETXATTR Generic Packet Structure",height=100]

//////////////////////////////////////////////////////////////////////
The mds-reint-setxattr-generic.png diagram resembles this text art:

        MDS_REINT:
      --REINT_SETXATTR-request-------------------------------------
      | ptlrpc_body | mdt_rec_setxattr | lustre_capa | mdt_ioepoc |
        eadata | llog_cookie | ldlm_request |
      -------------------------------------------------------------

      --REINT_SETXATTR-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.

'mdt_rec_setxattr'::
Information pertinent to setting extended 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.