LUDOC-276 protocol: Document RPCs for setattr

LUDOC-276 protocol: Document RPCs for setattr

[2015-06-09]
After Jinshan's second pass:

Section 7.1, page 36-37
  Added description of lov_mds_md

Section 13.12, page 51
Command 101: LDLM_ENQUEUE - Enqueue a loack request
  Lock Value Block discussion

Section 13.13, page 51
Command 1034: LDLM_CANCEL - Cancel a lock request
  Added the new discussion of the LDLM_CANCEL.

Section 14.4, page 64-68
  Updated the discussion of the 'setattr' for a 'truncate' with the
  details about the LDLM_CANCEL. Updated figures.

[2015-06-04]
Updates addressing Doug's comments. In particular, clarify how the
MDS_REINT structs are organized, and the constraints placed on the
interpretation of their fields in order to accommodate swabbing
correctly. Also, break the 'mdt_body' struct out into its own section,
in 'mdt_structs.txt', so that it does not seem to be another variant
of the 'mds_rec_reint'. Fix a minor markup issue in
'ost_setattr_structs.txt'.

[2015-05-31]
First round update in response to review:
Especially addressing defects in 'setattr.txt'.

Figures and text discuss RPCs that implement 'setattr'. There is a new
top-level file called 'extract_setattr.txt' that include just the new
content. It can be compiled with

  asciidoc extract_setattr.txt

for the HTML, and

  a2x -f pdf --fop extract_setattr.txt

for the PDF. The extract_setattr.pdf that results is also organized in
a more top-down fashion than the 'protocol.pdf'. We are still
considering which oreder of presentation (versus bottom-up) is
preferable. The figures each involves one of two kinds of thing:
either a UML-style sequence diagram (files ending in '_rpcs.png'), or
an RPC packet structure diagram.

The previously existing files data_types.txt,
file_system_operations.txt, ldlm.txt, lustre_messages.txt,
lustre_operations.txt, and protocol.txt all had very minor edits that
simply bring in the new content in the other files. The one excetion
is that previous content on LDLM has been improved and extended.

The setattr.txt file has the new content discussing 'setattr' in terms
of the RPCs that are exchanged. The remaining new files each
introduces one small piece of the new content relating to one specfic
detail, each.

Signed-off-by: Andrew C. Uselton <andrew.c.uselton@intel.com>
Change-Id: Iace0fc22d77372cb81d2ed9e2baca38327a8dee6
Reviewed-on: http://review.whamcloud.com/14852
Tested-by: Jenkins
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>