xref: /src/sys/dev/raidframe/rf_parityloggingdags.c

/*	$NetBSD: rf_parityloggingdags.c,v 1.2 1999/01/26 02:34:00 oster Exp $	*/
/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: William V. Courtright II
 *
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#include "rf_archs.h"

#if RF_INCLUDE_PARITYLOGGING > 0

/*
  DAGs specific to parity logging are created here
 */

#include "rf_types.h"
#include "rf_raid.h"
#include "rf_dag.h"
#include "rf_dagutils.h"
#include "rf_dagfuncs.h"
#include "rf_threadid.h"
#include "rf_debugMem.h"
#include "rf_paritylog.h"
#include "rf_memchunk.h"
#include "rf_general.h"

#include "rf_parityloggingdags.h"

/******************************************************************************
 *
 * creates a DAG to perform a large-write operation:
 *
 *         / Rod \     / Wnd \
 * H -- NIL- Rod - NIL - Wnd ------ NIL - T
 *         \ Rod /     \ Xor - Lpo /
 *
 * The writes are not done until the reads complete because if they were done in
 * parallel, a failure on one of the reads could leave the parity in an inconsistent
 * state, so that the retry with a new DAG would produce erroneous parity.
 *
 * Note:  this DAG has the nasty property that none of the buffers allocated for reading
 *        old data can be freed until the XOR node fires.  Need to fix this.
 *
 * The last two arguments are the number of faults tolerated, and function for the
 * redundancy calculation. The undo for the redundancy calc is assumed to be null
 *
 *****************************************************************************/

void rf_CommonCreateParityLoggingLargeWriteDAG(
  RF_Raid_t              *raidPtr,
  RF_AccessStripeMap_t   *asmap,
  RF_DagHeader_t         *dag_h,
  void                   *bp,
  RF_RaidAccessFlags_t    flags,
  RF_AllocListElem_t     *allocList,
  int                     nfaults,
  int                   (*redFunc)(RF_DagNode_t *))
{
  RF_DagNode_t *nodes, *wndNodes, *rodNodes=NULL, *syncNode, *xorNode, *lpoNode, *blockNode, *unblockNode, *termNode;
  int nWndNodes, nRodNodes, i;
  RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
  RF_AccessStripeMapHeader_t *new_asm_h[2];
  int nodeNum, asmNum;
  RF_ReconUnitNum_t which_ru;
  char *sosBuffer, *eosBuffer;
  RF_PhysDiskAddr_t *pda;
  RF_StripeNum_t parityStripeID = rf_RaidAddressToParityStripeID(&(raidPtr->Layout), asmap->raidAddress, &which_ru);

  if (rf_dagDebug)
    printf("[Creating parity-logging large-write DAG]\n");
  RF_ASSERT(nfaults == 1); /* this arch only single fault tolerant */
  dag_h->creator = "ParityLoggingLargeWriteDAG";

  /* alloc the Wnd nodes, the xor node, and the Lpo node */
  nWndNodes = asmap->numStripeUnitsAccessed;
  RF_CallocAndAdd(nodes, nWndNodes + 6, sizeof(RF_DagNode_t), (RF_DagNode_t *), allocList);
  i = 0;
  wndNodes    = &nodes[i]; i += nWndNodes;
  xorNode     = &nodes[i]; i += 1;
  lpoNode     = &nodes[i]; i += 1;
  blockNode   = &nodes[i]; i += 1;
  syncNode    = &nodes[i]; i += 1;
  unblockNode = &nodes[i]; i += 1;
  termNode    = &nodes[i]; i += 1;

  dag_h->numCommitNodes = nWndNodes + 1;
  dag_h->numCommits = 0;
  dag_h->numSuccedents = 1;

  rf_MapUnaccessedPortionOfStripe(raidPtr, layoutPtr, asmap, dag_h, new_asm_h, &nRodNodes, &sosBuffer, &eosBuffer, allocList);
  if (nRodNodes > 0)
    RF_CallocAndAdd(rodNodes, nRodNodes, sizeof(RF_DagNode_t), (RF_DagNode_t *), allocList);

  /* begin node initialization */
  rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nRodNodes + 1, 0, 0, 0, dag_h, "Nil", allocList);
  rf_InitNode(unblockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nWndNodes + 1, 0, 0, dag_h, "Nil", allocList);
  rf_InitNode(syncNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nWndNodes + 1, nRodNodes + 1, 0, 0, dag_h, "Nil", allocList);
  rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);

  /* initialize the Rod nodes */
  for (nodeNum = asmNum = 0; asmNum < 2; asmNum++) {
    if (new_asm_h[asmNum]) {
      pda = new_asm_h[asmNum]->stripeMap->physInfo;
      while (pda) {
	rf_InitNode(&rodNodes[nodeNum], rf_wait, RF_FALSE, rf_DiskReadFunc,rf_DiskReadUndoFunc,rf_GenericWakeupFunc,1,1,4,0, dag_h, "Rod", allocList);
	rodNodes[nodeNum].params[0].p = pda;
	rodNodes[nodeNum].params[1].p = pda->bufPtr;
	rodNodes[nodeNum].params[2].v = parityStripeID;
	rodNodes[nodeNum].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
	nodeNum++;
	pda=pda->next;
      }
    }
  }
  RF_ASSERT(nodeNum == nRodNodes);

  /* initialize the wnd nodes */
  pda = asmap->physInfo;
  for (i=0; i < nWndNodes; i++) {
    rf_InitNode(&wndNodes[i], rf_wait, RF_TRUE, rf_DiskWriteFunc, rf_DiskWriteUndoFunc, rf_GenericWakeupFunc, 1, 1, 4, 0, dag_h, "Wnd", allocList);
    RF_ASSERT(pda != NULL);
    wndNodes[i].params[0].p = pda;
    wndNodes[i].params[1].p = pda->bufPtr;
    wndNodes[i].params[2].v = parityStripeID;
    wndNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
    pda = pda->next;
  }

  /* initialize the redundancy node */
  rf_InitNode(xorNode, rf_wait, RF_TRUE, redFunc, rf_NullNodeUndoFunc, NULL, 1, 1, 2*(nWndNodes+nRodNodes)+1, 1, dag_h, "Xr ", allocList);
  xorNode->flags |= RF_DAGNODE_FLAG_YIELD;
  for (i=0; i < nWndNodes; i++) {
    xorNode->params[2*i+0] = wndNodes[i].params[0];         /* pda */
    xorNode->params[2*i+1] = wndNodes[i].params[1];         /* buf ptr */
  }
  for (i=0; i < nRodNodes; i++) {
    xorNode->params[2*(nWndNodes+i)+0] = rodNodes[i].params[0];         /* pda */
    xorNode->params[2*(nWndNodes+i)+1] = rodNodes[i].params[1];         /* buf ptr */
  }
  xorNode->params[2*(nWndNodes+nRodNodes)].p = raidPtr;  /* xor node needs to get at RAID information */

  /* look for an Rod node that reads a complete SU.  If none, alloc a buffer to receive the parity info.
   * Note that we can't use a new data buffer because it will not have gotten written when the xor occurs.
   */
  for (i = 0; i < nRodNodes; i++)
    if (((RF_PhysDiskAddr_t *) rodNodes[i].params[0].p)->numSector == raidPtr->Layout.sectorsPerStripeUnit)
      break;
  if (i == nRodNodes) {
    RF_CallocAndAdd(xorNode->results[0], 1, rf_RaidAddressToByte(raidPtr, raidPtr->Layout.sectorsPerStripeUnit), (void *), allocList);
  }
  else {
    xorNode->results[0] = rodNodes[i].params[1].p;
  }

  /* initialize the Lpo node */
  rf_InitNode(lpoNode, rf_wait, RF_FALSE, rf_ParityLogOverwriteFunc, rf_ParityLogOverwriteUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Lpo", allocList);

  lpoNode->params[0].p = asmap->parityInfo;
  lpoNode->params[1].p = xorNode->results[0];
  RF_ASSERT(asmap->parityInfo->next == NULL);        /* parityInfo must describe entire parity unit */

  /* connect nodes to form graph */

  /* connect dag header to block node */
  RF_ASSERT(dag_h->numSuccedents == 1);
  RF_ASSERT(blockNode->numAntecedents == 0);
  dag_h->succedents[0] = blockNode;

  /* connect the block node to the Rod nodes */
  RF_ASSERT(blockNode->numSuccedents == nRodNodes + 1);
  for (i = 0; i < nRodNodes; i++) {
    RF_ASSERT(rodNodes[i].numAntecedents == 1);
    blockNode->succedents[i] = &rodNodes[i];
    rodNodes[i].antecedents[0] = blockNode;
    rodNodes[i].antType[0] = rf_control;
  }

  /* connect the block node to the sync node */
  /* necessary if nRodNodes == 0 */
  RF_ASSERT(syncNode->numAntecedents == nRodNodes + 1);
  blockNode->succedents[nRodNodes] = syncNode;
  syncNode->antecedents[0] = blockNode;
  syncNode->antType[0] = rf_control;

  /* connect the Rod nodes to the syncNode */
  for (i = 0; i < nRodNodes; i++) {
    rodNodes[i].succedents[0] = syncNode;
    syncNode->antecedents[1 + i] = &rodNodes[i];
    syncNode->antType[1 + i] = rf_control;
  }

  /* connect the sync node to the xor node */
  RF_ASSERT(syncNode->numSuccedents == nWndNodes + 1);
  RF_ASSERT(xorNode->numAntecedents == 1);
  syncNode->succedents[0] = xorNode;
  xorNode->antecedents[0] = syncNode;
  xorNode->antType[0] = rf_trueData; /* carry forward from sync */

  /* connect the sync node to the Wnd nodes */
  for (i = 0; i < nWndNodes; i++) {
    RF_ASSERT(wndNodes->numAntecedents == 1);
    syncNode->succedents[1 + i] = &wndNodes[i];
    wndNodes[i].antecedents[0] = syncNode;
    wndNodes[i].antType[0] = rf_control;
  }

  /* connect the xor node to the Lpo node */
  RF_ASSERT(xorNode->numSuccedents == 1);
  RF_ASSERT(lpoNode->numAntecedents == 1);
  xorNode->succedents[0] = lpoNode;
  lpoNode->antecedents[0]= xorNode;
  lpoNode->antType[0] = rf_trueData;

  /* connect the Wnd nodes to the unblock node */
  RF_ASSERT(unblockNode->numAntecedents == nWndNodes + 1);
  for (i = 0; i < nWndNodes; i++) {
    RF_ASSERT(wndNodes->numSuccedents == 1);
    wndNodes[i].succedents[0] = unblockNode;
    unblockNode->antecedents[i] = &wndNodes[i];
    unblockNode->antType[i] = rf_control;
  }

  /* connect the Lpo node to the unblock node */
  RF_ASSERT(lpoNode->numSuccedents == 1);
  lpoNode->succedents[0] = unblockNode;
  unblockNode->antecedents[nWndNodes] = lpoNode;
  unblockNode->antType[nWndNodes] = rf_control;

  /* connect unblock node to terminator */
  RF_ASSERT(unblockNode->numSuccedents == 1);
  RF_ASSERT(termNode->numAntecedents == 1);
  RF_ASSERT(termNode->numSuccedents == 0);
  unblockNode->succedents[0] = termNode;
  termNode->antecedents[0] = unblockNode;
  termNode->antType[0] = rf_control;
}




/******************************************************************************
 *
 * creates a DAG to perform a small-write operation (either raid 5 or pq), which is as follows:
 *
 *                                     Header
 *                                       |
 *                                     Block
 *                                 / |  ... \   \
 *                                /  |       \   \
 *                             Rod  Rod      Rod  Rop
 *                             | \ /| \    / |  \/ |
 *                             |    |        |  /\ |
 *                             Wnd  Wnd      Wnd   X
 *                              |    \       /     |
 *                              |     \     /      |
 *                               \     \   /      Lpo
 *                                \     \ /       /
 *                                 +-> Unblock <-+
 *                                       |
 *                                       T
 *
 *
 * R = Read, W = Write, X = Xor, o = old, n = new, d = data, p = parity.
 * When the access spans a stripe unit boundary and is less than one SU in size, there will
 * be two Rop -- X -- Wnp branches.  I call this the "double-XOR" case.
 * The second output from each Rod node goes to the X node.  In the double-XOR
 * case, there are exactly 2 Rod nodes, and each sends one output to one X node.
 * There is one Rod -- Wnd -- T branch for each stripe unit being updated.
 *
 * The block and unblock nodes are unused.  See comment above CreateFaultFreeReadDAG.
 *
 * Note:  this DAG ignores all the optimizations related to making the RMWs atomic.
 *        it also has the nasty property that none of the buffers allocated for reading
 *        old data & parity can be freed until the XOR node fires.  Need to fix this.
 *
 * A null qfuncs indicates single fault tolerant
 *****************************************************************************/

void rf_CommonCreateParityLoggingSmallWriteDAG(
  RF_Raid_t             *raidPtr,
  RF_AccessStripeMap_t  *asmap,
  RF_DagHeader_t        *dag_h,
  void                  *bp,
  RF_RaidAccessFlags_t   flags,
  RF_AllocListElem_t    *allocList,
  RF_RedFuncs_t         *pfuncs,
  RF_RedFuncs_t         *qfuncs)
{
  RF_DagNode_t *xorNodes, *blockNode, *unblockNode, *nodes;
  RF_DagNode_t *readDataNodes, *readParityNodes;
  RF_DagNode_t *writeDataNodes, *lpuNodes;
  RF_DagNode_t *unlockDataNodes=NULL, *termNode;
  RF_PhysDiskAddr_t *pda = asmap->physInfo;
  int numDataNodes = asmap->numStripeUnitsAccessed;
  int numParityNodes = (asmap->parityInfo->next) ? 2 : 1;
  int i, j, nNodes, totalNumNodes;
  RF_ReconUnitNum_t which_ru;
  int (*func)(RF_DagNode_t *node), (*undoFunc)(RF_DagNode_t *node);
  int (*qfunc)(RF_DagNode_t *node);
  char *name, *qname;
  RF_StripeNum_t parityStripeID = rf_RaidAddressToParityStripeID(&(raidPtr->Layout), asmap->raidAddress, &which_ru);
  long nfaults = qfuncs ? 2 : 1;
  int lu_flag = (rf_enableAtomicRMW) ? 1 : 0;          /* lock/unlock flag */

  if (rf_dagDebug) printf("[Creating parity-logging small-write DAG]\n");
  RF_ASSERT(numDataNodes > 0);
  RF_ASSERT(nfaults == 1);
  dag_h->creator = "ParityLoggingSmallWriteDAG";

  /* DAG creation occurs in three steps:
     1. count the number of nodes in the DAG
     2. create the nodes
     3. initialize the nodes
     4. connect the nodes
   */

  /* Step 1. compute number of nodes in the graph */

  /* number of nodes:
      a read and write for each data unit
      a redundancy computation node for each parity node
      a read and Lpu for each parity unit
      a block and unblock node (2)
      a terminator node
      if atomic RMW
        an unlock node for each data unit, redundancy unit
  */
  totalNumNodes = (2 * numDataNodes) + numParityNodes + (2 * numParityNodes) + 3;
  if (lu_flag)
    totalNumNodes += numDataNodes;

  nNodes     = numDataNodes + numParityNodes;

  dag_h->numCommitNodes = numDataNodes + numParityNodes;
  dag_h->numCommits = 0;
  dag_h->numSuccedents = 1;

  /* Step 2. create the nodes */
  RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t), (RF_DagNode_t *), allocList);
  i = 0;
  blockNode         = &nodes[i]; i += 1;
  unblockNode       = &nodes[i]; i += 1;
  readDataNodes     = &nodes[i]; i += numDataNodes;
  readParityNodes   = &nodes[i]; i += numParityNodes;
  writeDataNodes    = &nodes[i]; i += numDataNodes;
  lpuNodes          = &nodes[i]; i += numParityNodes;
  xorNodes          = &nodes[i]; i += numParityNodes;
  termNode          = &nodes[i]; i += 1;
  if (lu_flag) {
    unlockDataNodes = &nodes[i]; i += numDataNodes;
  }
  RF_ASSERT(i == totalNumNodes);

  /* Step 3. initialize the nodes */
  /* initialize block node (Nil) */
  rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nNodes, 0, 0, 0, dag_h, "Nil", allocList);

  /* initialize unblock node (Nil) */
  rf_InitNode(unblockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nNodes, 0, 0, dag_h, "Nil", allocList);

  /* initialize terminatory node (Trm) */
  rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);

  /* initialize nodes which read old data (Rod) */
  for (i = 0; i < numDataNodes; i++) {
    rf_InitNode(&readDataNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rod", allocList);
    RF_ASSERT(pda != NULL);
    readDataNodes[i].params[0].p = pda; /* physical disk addr desc */
    readDataNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda, allocList);  /* buffer to hold old data */
    readDataNodes[i].params[2].v = parityStripeID;
    readDataNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, lu_flag, 0, which_ru);
    pda=pda->next;
    readDataNodes[i].propList[0] = NULL;
    readDataNodes[i].propList[1] = NULL;
  }

  /* initialize nodes which read old parity (Rop) */
  pda = asmap->parityInfo; i = 0;
  for (i = 0; i < numParityNodes; i++) {
    RF_ASSERT(pda != NULL);
    rf_InitNode(&readParityNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rop", allocList);
    readParityNodes[i].params[0].p = pda;
    readParityNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda, allocList);    /* buffer to hold old parity */
    readParityNodes[i].params[2].v = parityStripeID;
    readParityNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
    readParityNodes[i].propList[0] = NULL;
    pda=pda->next;
  }

  /* initialize nodes which write new data (Wnd) */
  pda = asmap->physInfo;
  for (i=0; i < numDataNodes; i++) {
    RF_ASSERT(pda != NULL);
    rf_InitNode(&writeDataNodes[i], rf_wait, RF_TRUE, rf_DiskWriteFunc, rf_DiskWriteUndoFunc, rf_GenericWakeupFunc, 1, nNodes, 4, 0, dag_h, "Wnd", allocList);
    writeDataNodes[i].params[0].p = pda;                    /* physical disk addr desc */
    writeDataNodes[i].params[1].p = pda->bufPtr;   /* buffer holding new data to be written */
    writeDataNodes[i].params[2].v = parityStripeID;
    writeDataNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);

    if (lu_flag) {
      /* initialize node to unlock the disk queue */
      rf_InitNode(&unlockDataNodes[i], rf_wait, RF_FALSE, rf_DiskUnlockFunc, rf_DiskUnlockUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Und", allocList);
      unlockDataNodes[i].params[0].p = pda; /* physical disk addr desc */
      unlockDataNodes[i].params[1].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, lu_flag, which_ru);
    }
    pda = pda->next;
  }


  /* initialize nodes which compute new parity */
  /* we use the simple XOR func in the double-XOR case, and when we're accessing only a portion of one stripe unit.
   * the distinction between the two is that the regular XOR func assumes that the targbuf is a full SU in size,
   * and examines the pda associated with the buffer to decide where within the buffer to XOR the data, whereas
   * the simple XOR func just XORs the data into the start of the buffer.
   */
  if ((numParityNodes==2) || ((numDataNodes == 1) && (asmap->totalSectorsAccessed < raidPtr->Layout.sectorsPerStripeUnit))) {
    func = pfuncs->simple; undoFunc = rf_NullNodeUndoFunc; name = pfuncs->SimpleName;
    if (qfuncs)
      { qfunc = qfuncs->simple; qname = qfuncs->SimpleName;}
  } else {
    func = pfuncs->regular; undoFunc = rf_NullNodeUndoFunc; name = pfuncs->RegularName;
    if (qfuncs) { qfunc = qfuncs->regular; qname = qfuncs->RegularName;}
  }
  /* initialize the xor nodes: params are {pda,buf} from {Rod,Wnd,Rop} nodes, and raidPtr  */
  if (numParityNodes==2) {        /* double-xor case */
    for (i=0; i < numParityNodes; i++) {
      rf_InitNode(&xorNodes[i], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, 7, 1, dag_h, name, allocList);  /* no wakeup func for xor */
      xorNodes[i].flags |= RF_DAGNODE_FLAG_YIELD;
      xorNodes[i].params[0] = readDataNodes[i].params[0];
      xorNodes[i].params[1] = readDataNodes[i].params[1];
      xorNodes[i].params[2] = readParityNodes[i].params[0];
      xorNodes[i].params[3] = readParityNodes[i].params[1];
      xorNodes[i].params[4] = writeDataNodes[i].params[0];
      xorNodes[i].params[5] = writeDataNodes[i].params[1];
      xorNodes[i].params[6].p = raidPtr;
      xorNodes[i].results[0] = readParityNodes[i].params[1].p;   /* use old parity buf as target buf */
    }
  }
  else {
    /* there is only one xor node in this case */
    rf_InitNode(&xorNodes[0], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, (2 * (numDataNodes + numDataNodes + 1) + 1), 1, dag_h, name, allocList);
    xorNodes[0].flags |= RF_DAGNODE_FLAG_YIELD;
    for (i=0; i < numDataNodes + 1; i++) {
      /* set up params related to Rod and Rop nodes */
      xorNodes[0].params[2*i+0] = readDataNodes[i].params[0];    /* pda */
      xorNodes[0].params[2*i+1] = readDataNodes[i].params[1];    /* buffer pointer */
    }
    for (i=0; i < numDataNodes; i++) {
      /* set up params related to Wnd and Wnp nodes */
      xorNodes[0].params[2*(numDataNodes+1+i)+0] = writeDataNodes[i].params[0]; /* pda */
      xorNodes[0].params[2*(numDataNodes+1+i)+1] = writeDataNodes[i].params[1]; /* buffer pointer */
    }
    xorNodes[0].params[2*(numDataNodes+numDataNodes+1)].p = raidPtr;  /* xor node needs to get at RAID information */
    xorNodes[0].results[0] = readParityNodes[0].params[1].p;
  }

  /* initialize the log node(s) */
  pda = asmap->parityInfo;
  for (i = 0;  i < numParityNodes; i++) {
    RF_ASSERT(pda);
    rf_InitNode(&lpuNodes[i], rf_wait, RF_FALSE, rf_ParityLogUpdateFunc, rf_ParityLogUpdateUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Lpu", allocList);
    lpuNodes[i].params[0].p = pda;                    /* PhysDiskAddr of parity */
    lpuNodes[i].params[1].p = xorNodes[i].results[0]; /* buffer pointer to parity */
    pda = pda->next;
  }


  /* Step 4. connect the nodes */

  /* connect header to block node */
  RF_ASSERT(dag_h->numSuccedents == 1);
  RF_ASSERT(blockNode->numAntecedents == 0);
  dag_h->succedents[0] = blockNode;

  /* connect block node to read old data nodes */
  RF_ASSERT(blockNode->numSuccedents == (numDataNodes + numParityNodes));
  for (i = 0; i < numDataNodes; i++) {
    blockNode->succedents[i] = &readDataNodes[i];
    RF_ASSERT(readDataNodes[i].numAntecedents == 1);
    readDataNodes[i].antecedents[0]= blockNode;
    readDataNodes[i].antType[0] = rf_control;
  }

  /* connect block node to read old parity nodes */
  for (i = 0; i < numParityNodes; i++) {
    blockNode->succedents[numDataNodes + i] = &readParityNodes[i];
    RF_ASSERT(readParityNodes[i].numAntecedents == 1);
    readParityNodes[i].antecedents[0] = blockNode;
    readParityNodes[i].antType[0] = rf_control;
  }

  /* connect read old data nodes to write new data nodes */
  for (i = 0; i < numDataNodes; i++) {
    RF_ASSERT(readDataNodes[i].numSuccedents == numDataNodes + numParityNodes);
    for (j = 0; j < numDataNodes; j++) {
      RF_ASSERT(writeDataNodes[j].numAntecedents == numDataNodes + numParityNodes);
      readDataNodes[i].succedents[j] = &writeDataNodes[j];
      writeDataNodes[j].antecedents[i] = &readDataNodes[i];
      if (i == j)
	writeDataNodes[j].antType[i] = rf_antiData;
      else
	writeDataNodes[j].antType[i] = rf_control;
    }
  }

  /* connect read old data nodes to xor nodes */
  for (i = 0; i < numDataNodes; i++)
    for (j = 0; j < numParityNodes; j++){
      RF_ASSERT(xorNodes[j].numAntecedents == numDataNodes + numParityNodes);
      readDataNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
      xorNodes[j].antecedents[i] = &readDataNodes[i];
      xorNodes[j].antType[i] = rf_trueData;
    }

  /* connect read old parity nodes to write new data nodes */
  for (i = 0; i < numParityNodes; i++) {
    RF_ASSERT(readParityNodes[i].numSuccedents == numDataNodes + numParityNodes);
    for (j = 0; j < numDataNodes; j++) {
      readParityNodes[i].succedents[j] = &writeDataNodes[j];
      writeDataNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
      writeDataNodes[j].antType[numDataNodes + i] = rf_control;
    }
  }

  /* connect read old parity nodes to xor nodes */
  for (i = 0; i < numParityNodes; i++)
    for (j = 0; j < numParityNodes; j++) {
      readParityNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
      xorNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
      xorNodes[j].antType[numDataNodes + i] = rf_trueData;
    }

  /* connect xor nodes to write new parity nodes */
  for (i = 0; i < numParityNodes; i++) {
    RF_ASSERT(xorNodes[i].numSuccedents == 1);
    RF_ASSERT(lpuNodes[i].numAntecedents == 1);
    xorNodes[i].succedents[0] = &lpuNodes[i];
    lpuNodes[i].antecedents[0] = &xorNodes[i];
    lpuNodes[i].antType[0] = rf_trueData;
  }

  for (i = 0; i < numDataNodes; i++) {
    if (lu_flag) {
      /* connect write new data nodes to unlock nodes */
      RF_ASSERT(writeDataNodes[i].numSuccedents == 1);
      RF_ASSERT(unlockDataNodes[i].numAntecedents == 1);
      writeDataNodes[i].succedents[0] = &unlockDataNodes[i];
      unlockDataNodes[i].antecedents[0] = &writeDataNodes[i];
      unlockDataNodes[i].antType[0] = rf_control;

      /* connect unlock nodes to unblock node */
      RF_ASSERT(unlockDataNodes[i].numSuccedents == 1);
      RF_ASSERT(unblockNode->numAntecedents == (numDataNodes + (nfaults * numParityNodes)));
      unlockDataNodes[i].succedents[0] = unblockNode;
      unblockNode->antecedents[i] = &unlockDataNodes[i];
      unblockNode->antType[i] = rf_control;
    }
    else {
      /* connect write new data nodes to unblock node */
      RF_ASSERT(writeDataNodes[i].numSuccedents == 1);
      RF_ASSERT(unblockNode->numAntecedents == (numDataNodes + (nfaults * numParityNodes)));
      writeDataNodes[i].succedents[0] = unblockNode;
      unblockNode->antecedents[i] = &writeDataNodes[i];
      unblockNode->antType[i] = rf_control;
    }
  }

  /* connect write new parity nodes to unblock node */
  for (i = 0; i < numParityNodes; i++) {
    RF_ASSERT(lpuNodes[i].numSuccedents == 1);
    lpuNodes[i].succedents[0] = unblockNode;
    unblockNode->antecedents[numDataNodes + i] = &lpuNodes[i];
    unblockNode->antType[numDataNodes + i] = rf_control;
  }

  /* connect unblock node to terminator */
  RF_ASSERT(unblockNode->numSuccedents == 1);
  RF_ASSERT(termNode->numAntecedents == 1);
  RF_ASSERT(termNode->numSuccedents == 0);
  unblockNode->succedents[0] = termNode;
  termNode->antecedents[0] = unblockNode;
  termNode->antType[0] = rf_control;
}


void rf_CreateParityLoggingSmallWriteDAG(
  RF_Raid_t             *raidPtr,
  RF_AccessStripeMap_t  *asmap,
  RF_DagHeader_t        *dag_h,
  void                  *bp,
  RF_RaidAccessFlags_t   flags,
  RF_AllocListElem_t    *allocList,
  RF_RedFuncs_t         *pfuncs,
  RF_RedFuncs_t         *qfuncs)
{
  dag_h->creator = "ParityLoggingSmallWriteDAG";
  rf_CommonCreateParityLoggingSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_xorFuncs, NULL);
}


void rf_CreateParityLoggingLargeWriteDAG(
  RF_Raid_t              *raidPtr,
  RF_AccessStripeMap_t   *asmap,
  RF_DagHeader_t         *dag_h,
  void                   *bp,
  RF_RaidAccessFlags_t    flags,
  RF_AllocListElem_t     *allocList,
  int                     nfaults,
  int                   (*redFunc)(RF_DagNode_t *))
{
  dag_h->creator = "ParityLoggingSmallWriteDAG";
  rf_CommonCreateParityLoggingLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularXorFunc);
}

#endif /* RF_INCLUDE_PARITYLOGGING > 0 */