release/src-rt-6.x.4708/linux/linux-2.6.36/Documentation/blockdev/drbd/drbd-connection-state-overview.dot

   1 // vim: set sw=2 sts=2 :
   2 digraph {
   3   rankdir=BT
   4   bgcolor=white
   5
   6   node [shape=plaintext]
   7   node [fontcolor=black]
   8
   9   StandAlone     [ style=filled,fillcolor=gray,label=StandAlone ]
  10
  11   node [fontcolor=lightgray]
  12
  13   Unconnected    [ label=Unconnected ]
  14
  15   CommTrouble [ shape=record,
  16     label="{communication loss|{Timeout|BrokenPipe|NetworkFailure}}" ]
  17
  18   node [fontcolor=gray]
  19
  20   subgraph cluster_try_connect {
  21     label="try to connect, handshake"
  22     rank=max
  23     WFConnection   [ label=WFConnection ]
  24     WFReportParams [ label=WFReportParams ]
  25   }
  26
  27   TearDown       [ label=TearDown ]
  28
  29   Connected      [ label=Connected,style=filled,fillcolor=green,fontcolor=black ]
  30
  31   node [fontcolor=lightblue]
  32
  33   StartingSyncS  [ label=StartingSyncS ]
  34   StartingSyncT  [ label=StartingSyncT ]
  35
  36   subgraph cluster_bitmap_exchange {
  37     node [fontcolor=red]
  38     fontcolor=red
  39     label="new application (WRITE?) requests blocked\lwhile bitmap is exchanged"
  40
  41     WFBitMapT      [ label=WFBitMapT ]
  42     WFSyncUUID     [ label=WFSyncUUID ]
  43     WFBitMapS      [ label=WFBitMapS ]
  44   }
  45
  46   node [fontcolor=blue]
  47
  48   cluster_resync [ shape=record,label="{<any>resynchronisation process running\l'concurrent' application requests allowed|{{<T>PausedSyncT\nSyncTarget}|{<S>PausedSyncS\nSyncSource}}}" ]
  49
  50   node [shape=box,fontcolor=black]
  51
  52   // drbdadm [label="drbdadm connect"]
  53   // handshake [label="drbd_connect()\ndrbd_do_handshake\ndrbd_sync_handshake() etc."]
  54   // comm_error [label="communication trouble"]
  55
  56   //
  57   // edges
  58   // --------------------------------------
  59
  60   StandAlone -> Unconnected [ label="drbdadm connect" ]
  61   Unconnected -> StandAlone  [ label="drbdadm disconnect\lor serious communication trouble" ]
  62   Unconnected -> WFConnection [ label="receiver thread is started" ]
  63   WFConnection -> WFReportParams [ headlabel="accept()\land/or                        \lconnect()\l" ]
  64
  65   WFReportParams -> StandAlone [ label="during handshake\lpeers do not agree\labout something essential" ]
  66   WFReportParams -> Connected [ label="data identical\lno sync needed",color=green,fontcolor=green ]
  67
  68     WFReportParams -> WFBitMapS
  69     WFReportParams -> WFBitMapT
  70     WFBitMapT -> WFSyncUUID [minlen=0.1,constraint=false]
  71
  72       WFBitMapS -> cluster_resync:S
  73       WFSyncUUID -> cluster_resync:T
  74
  75   edge [color=green]
  76   cluster_resync:any -> Connected [ label="resnyc done",fontcolor=green ]
  77
  78   edge [color=red]
  79   WFReportParams -> CommTrouble
  80   Connected -> CommTrouble
  81   cluster_resync:any -> CommTrouble
  82   edge [color=black]
  83   CommTrouble -> Unconnected [label="receiver thread is stopped" ]
  84
  85 }