LUDOC-297 protocol: Update protocol document

[doc/protocol.git] / statfs.txt

diff --git a/statfs.txt b/statfs.txt
index a11f231..336a168 100644 (file)
--- a/statfs.txt
+++ b/statfs.txt
@@ -2,15 +2,14 @@ Statfs
 ~~~~~~
 
 The 'statfs' VFS method queries file-system-wide space and inode
-usage. For details about the MDS_STATFS RPC, including possible faults
-and error return codes, see <<mds-statfs-rpc>>, and for OST_STATFS see
-<<ost-statfs-rpc>>.
+usage. For details about the MDS_STATFS RPC see <<mds-statfs-rpc>>,
+and for OST_STATFS see <<ost-statfs-rpc>>.
 
 A client gets 'statfs' information for the file system as a whole by
-first querying the individual storage targets for the 'statfs'
-information on each back-end file system. The RPCs that flow are as
-shown in <<statfs-rpcs>>. The values returned in the VFS call are
-built from the results of the *_STATFS RPCs as follows:
+first querying the individual storage targets (OSDs) for their
+'statfs' information. The RPCs that flow are as shown in
+<<statfs-rpcs>>. The values returned in the VFS call are built from
+the results of the *_STATFS RPCs as follows:
 
 .Statfs values
 [options="header"]
@@ -77,22 +76,21 @@ Step Client         MDT          OST
 
 The MDS_STATFS request is a so-called 'empty' RPC in that it consists
 only of the 'ptlrpc_body' (Lustre RPC descriptor) with the opcode set to
-MDS_STATFS (41). Refer to the discussion of <<mds-statfs-rpc>> for
-more general information about the MDS_STATFS RPC's request and reply
-messages.
+MDS_STATFS (41).
 
 .MDS_STATFS Request Packet Structure
+image::mds-statfs-request.png["MDS_STATFS Request Packet Structure",height=50]
 
-:frame: none
-:grid: none
-[width="50%", cols="2a"]
-|====
-| request
-[cols="1"]
-!===================
-! <<struct-ptlrpc-body,ptlrpc_body>> !
-!===================
-|====
+//////////////////////////////////////////////////////////////////////
+The mds-statfs-request.png diagram resembles this text art:
+
+       MDS_STATFS:
+      --request------
+      | ptlrpc_body |
+      ---------------
+//////////////////////////////////////////////////////////////////////
+
+See <<mds-statfs-rpc>>.
 
 *2 - The MDS_STATFS reply returns 'statfs' info*
 
@@ -102,17 +100,16 @@ detailed discussion of the fields in the 'obd_statfs' refer to
 <<struct-obd-statfs>>.
 
 .MDS_STATFS Reply Packet Structure
+image::mds-statfs-reply.png["MDS_STATFS Reply Packet Structure",height=50]
 
-:frame: none
-:grid: none
-[width="50%", cols="2a"]
-|====
-| reply
-[cols="2"]
-!===================
-! <<struct-ptlrpc-body,ptlrpc_body>> ! <<struct-obd-statfs,obd_statfs>> !
-!===================
-|====
+//////////////////////////////////////////////////////////////////////
+The mds-statfs-reply.png diagram resembles this text art:
+
+       MDS_STATFS:
+      --reply---------------------
+      | ptlrpc_body | obd_statfs |
+      ----------------------------
+//////////////////////////////////////////////////////////////////////
 
 *3 - The client issues an OST_STATFS request to each OST.*
 
@@ -121,18 +118,18 @@ is 13 instead of 41 and the target of the RPC is an OST instead of an
 MDT.
 
 .OST_STATFS Request Packet Structure
+image::ost-statfs-request.png["OST_STATFS Request Packet Structure",height=50]
 
-:frame: none
-:grid: none
-[width="50%", cols="2a"]
-|====
-| request
-[cols="1"]
-!===================
-! <<struct-ptlrpc-body,ptlrpc_body>> !
-!===================
-|====
+//////////////////////////////////////////////////////////////////////
+The ost-statfs-request.png diagram resembles this text art:
+
+       OST_STATFS:
+      --request------
+      | ptlrpc_body |
+      ---------------
+//////////////////////////////////////////////////////////////////////
 
+See <<mds-statfs-rpc>>.
 
 *4 - The OST_STATFS reply returns 'statfs' info*
 
@@ -142,14 +139,13 @@ discussion of the fields in the 'obd_statfs' refer to
 <<struct-obd-statfs>>.
 
 .OST_STATFS Reply Packet Structure
+image::ost-statfs-reply.png["OST_STATFS Reply Packet Structure",height=50]
 
-:frame: none
-:grid: none
-[width="50%", cols="2a"]
-|====
-| reply
-[cols="2"]
-!===================
-! <<struct-ptlrpc-body,ptlrpc_body>> ! <<struct-obd-statfs,obd_statfs>> !
-!===================
-|====
+//////////////////////////////////////////////////////////////////////
+The ost-statfs-reply.png diagram resembles this text art:
+
+       OST_STATFS:
+      --reply---------------------
+      | ptlrpc_body | obd_statfs |
+      ----------------------------
+//////////////////////////////////////////////////////////////////////