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rf_parityloggingdags.c revision 1.5
      1 /*	$NetBSD: rf_parityloggingdags.c,v 1.5 2001/09/01 23:50:44 thorpej Exp $	*/
      2 /*
      3  * Copyright (c) 1995 Carnegie-Mellon University.
      4  * All rights reserved.
      5  *
      6  * Author: William V. Courtright II
      7  *
      8  * Permission to use, copy, modify and distribute this software and
      9  * its documentation is hereby granted, provided that both the copyright
     10  * notice and this permission notice appear in all copies of the
     11  * software, derivative works or modified versions, and any portions
     12  * thereof, and that both notices appear in supporting documentation.
     13  *
     14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     16  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     17  *
     18  * Carnegie Mellon requests users of this software to return to
     19  *
     20  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     21  *  School of Computer Science
     22  *  Carnegie Mellon University
     23  *  Pittsburgh PA 15213-3890
     24  *
     25  * any improvements or extensions that they make and grant Carnegie the
     26  * rights to redistribute these changes.
     27  */
     28 
     29 #include "rf_archs.h"
     30 
     31 #if RF_INCLUDE_PARITYLOGGING > 0
     32 
     33 /*
     34   DAGs specific to parity logging are created here
     35  */
     36 
     37 #include "rf_types.h"
     38 #include "rf_raid.h"
     39 #include "rf_dag.h"
     40 #include "rf_dagutils.h"
     41 #include "rf_dagfuncs.h"
     42 #include "rf_debugMem.h"
     43 #include "rf_paritylog.h"
     44 #include "rf_memchunk.h"
     45 #include "rf_general.h"
     46 
     47 #include "rf_parityloggingdags.h"
     48 
     49 /******************************************************************************
     50  *
     51  * creates a DAG to perform a large-write operation:
     52  *
     53  *         / Rod \     / Wnd \
     54  * H -- NIL- Rod - NIL - Wnd ------ NIL - T
     55  *         \ Rod /     \ Xor - Lpo /
     56  *
     57  * The writes are not done until the reads complete because if they were done in
     58  * parallel, a failure on one of the reads could leave the parity in an inconsistent
     59  * state, so that the retry with a new DAG would produce erroneous parity.
     60  *
     61  * Note:  this DAG has the nasty property that none of the buffers allocated for reading
     62  *        old data can be freed until the XOR node fires.  Need to fix this.
     63  *
     64  * The last two arguments are the number of faults tolerated, and function for the
     65  * redundancy calculation. The undo for the redundancy calc is assumed to be null
     66  *
     67  *****************************************************************************/
     68 
     69 void
     70 rf_CommonCreateParityLoggingLargeWriteDAG(
     71     RF_Raid_t * raidPtr,
     72     RF_AccessStripeMap_t * asmap,
     73     RF_DagHeader_t * dag_h,
     74     void *bp,
     75     RF_RaidAccessFlags_t flags,
     76     RF_AllocListElem_t * allocList,
     77     int nfaults,
     78     int (*redFunc) (RF_DagNode_t *))
     79 {
     80 	RF_DagNode_t *nodes, *wndNodes, *rodNodes = NULL, *syncNode, *xorNode,
     81 	       *lpoNode, *blockNode, *unblockNode, *termNode;
     82 	int     nWndNodes, nRodNodes, i;
     83 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
     84 	RF_AccessStripeMapHeader_t *new_asm_h[2];
     85 	int     nodeNum, asmNum;
     86 	RF_ReconUnitNum_t which_ru;
     87 	char   *sosBuffer, *eosBuffer;
     88 	RF_PhysDiskAddr_t *pda;
     89 	RF_StripeNum_t parityStripeID = rf_RaidAddressToParityStripeID(&(raidPtr->Layout), asmap->raidAddress, &which_ru);
     90 
     91 	if (rf_dagDebug)
     92 		printf("[Creating parity-logging large-write DAG]\n");
     93 	RF_ASSERT(nfaults == 1);/* this arch only single fault tolerant */
     94 	dag_h->creator = "ParityLoggingLargeWriteDAG";
     95 
     96 	/* alloc the Wnd nodes, the xor node, and the Lpo node */
     97 	nWndNodes = asmap->numStripeUnitsAccessed;
     98 	RF_CallocAndAdd(nodes, nWndNodes + 6, sizeof(RF_DagNode_t), (RF_DagNode_t *), allocList);
     99 	i = 0;
    100 	wndNodes = &nodes[i];
    101 	i += nWndNodes;
    102 	xorNode = &nodes[i];
    103 	i += 1;
    104 	lpoNode = &nodes[i];
    105 	i += 1;
    106 	blockNode = &nodes[i];
    107 	i += 1;
    108 	syncNode = &nodes[i];
    109 	i += 1;
    110 	unblockNode = &nodes[i];
    111 	i += 1;
    112 	termNode = &nodes[i];
    113 	i += 1;
    114 
    115 	dag_h->numCommitNodes = nWndNodes + 1;
    116 	dag_h->numCommits = 0;
    117 	dag_h->numSuccedents = 1;
    118 
    119 	rf_MapUnaccessedPortionOfStripe(raidPtr, layoutPtr, asmap, dag_h, new_asm_h, &nRodNodes, &sosBuffer, &eosBuffer, allocList);
    120 	if (nRodNodes > 0)
    121 		RF_CallocAndAdd(rodNodes, nRodNodes, sizeof(RF_DagNode_t), (RF_DagNode_t *), allocList);
    122 
    123 	/* begin node initialization */
    124 	rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nRodNodes + 1, 0, 0, 0, dag_h, "Nil", allocList);
    125 	rf_InitNode(unblockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nWndNodes + 1, 0, 0, dag_h, "Nil", allocList);
    126 	rf_InitNode(syncNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nWndNodes + 1, nRodNodes + 1, 0, 0, dag_h, "Nil", allocList);
    127 	rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
    128 
    129 	/* initialize the Rod nodes */
    130 	for (nodeNum = asmNum = 0; asmNum < 2; asmNum++) {
    131 		if (new_asm_h[asmNum]) {
    132 			pda = new_asm_h[asmNum]->stripeMap->physInfo;
    133 			while (pda) {
    134 				rf_InitNode(&rodNodes[nodeNum], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, 1, 1, 4, 0, dag_h, "Rod", allocList);
    135 				rodNodes[nodeNum].params[0].p = pda;
    136 				rodNodes[nodeNum].params[1].p = pda->bufPtr;
    137 				rodNodes[nodeNum].params[2].v = parityStripeID;
    138 				rodNodes[nodeNum].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
    139 				nodeNum++;
    140 				pda = pda->next;
    141 			}
    142 		}
    143 	}
    144 	RF_ASSERT(nodeNum == nRodNodes);
    145 
    146 	/* initialize the wnd nodes */
    147 	pda = asmap->physInfo;
    148 	for (i = 0; i < nWndNodes; i++) {
    149 		rf_InitNode(&wndNodes[i], rf_wait, RF_TRUE, rf_DiskWriteFunc, rf_DiskWriteUndoFunc, rf_GenericWakeupFunc, 1, 1, 4, 0, dag_h, "Wnd", allocList);
    150 		RF_ASSERT(pda != NULL);
    151 		wndNodes[i].params[0].p = pda;
    152 		wndNodes[i].params[1].p = pda->bufPtr;
    153 		wndNodes[i].params[2].v = parityStripeID;
    154 		wndNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
    155 		pda = pda->next;
    156 	}
    157 
    158 	/* initialize the redundancy node */
    159 	rf_InitNode(xorNode, rf_wait, RF_TRUE, redFunc, rf_NullNodeUndoFunc, NULL, 1, 1, 2 * (nWndNodes + nRodNodes) + 1, 1, dag_h, "Xr ", allocList);
    160 	xorNode->flags |= RF_DAGNODE_FLAG_YIELD;
    161 	for (i = 0; i < nWndNodes; i++) {
    162 		xorNode->params[2 * i + 0] = wndNodes[i].params[0];	/* pda */
    163 		xorNode->params[2 * i + 1] = wndNodes[i].params[1];	/* buf ptr */
    164 	}
    165 	for (i = 0; i < nRodNodes; i++) {
    166 		xorNode->params[2 * (nWndNodes + i) + 0] = rodNodes[i].params[0];	/* pda */
    167 		xorNode->params[2 * (nWndNodes + i) + 1] = rodNodes[i].params[1];	/* buf ptr */
    168 	}
    169 	xorNode->params[2 * (nWndNodes + nRodNodes)].p = raidPtr;	/* xor node needs to get
    170 									 * at RAID information */
    171 
    172 	/* look for an Rod node that reads a complete SU.  If none, alloc a
    173 	 * buffer to receive the parity info. Note that we can't use a new
    174 	 * data buffer because it will not have gotten written when the xor
    175 	 * occurs. */
    176 	for (i = 0; i < nRodNodes; i++)
    177 		if (((RF_PhysDiskAddr_t *) rodNodes[i].params[0].p)->numSector == raidPtr->Layout.sectorsPerStripeUnit)
    178 			break;
    179 	if (i == nRodNodes) {
    180 		RF_CallocAndAdd(xorNode->results[0], 1, rf_RaidAddressToByte(raidPtr, raidPtr->Layout.sectorsPerStripeUnit), (void *), allocList);
    181 	} else {
    182 		xorNode->results[0] = rodNodes[i].params[1].p;
    183 	}
    184 
    185 	/* initialize the Lpo node */
    186 	rf_InitNode(lpoNode, rf_wait, RF_FALSE, rf_ParityLogOverwriteFunc, rf_ParityLogOverwriteUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Lpo", allocList);
    187 
    188 	lpoNode->params[0].p = asmap->parityInfo;
    189 	lpoNode->params[1].p = xorNode->results[0];
    190 	RF_ASSERT(asmap->parityInfo->next == NULL);	/* parityInfo must
    191 							 * describe entire
    192 							 * parity unit */
    193 
    194 	/* connect nodes to form graph */
    195 
    196 	/* connect dag header to block node */
    197 	RF_ASSERT(dag_h->numSuccedents == 1);
    198 	RF_ASSERT(blockNode->numAntecedents == 0);
    199 	dag_h->succedents[0] = blockNode;
    200 
    201 	/* connect the block node to the Rod nodes */
    202 	RF_ASSERT(blockNode->numSuccedents == nRodNodes + 1);
    203 	for (i = 0; i < nRodNodes; i++) {
    204 		RF_ASSERT(rodNodes[i].numAntecedents == 1);
    205 		blockNode->succedents[i] = &rodNodes[i];
    206 		rodNodes[i].antecedents[0] = blockNode;
    207 		rodNodes[i].antType[0] = rf_control;
    208 	}
    209 
    210 	/* connect the block node to the sync node */
    211 	/* necessary if nRodNodes == 0 */
    212 	RF_ASSERT(syncNode->numAntecedents == nRodNodes + 1);
    213 	blockNode->succedents[nRodNodes] = syncNode;
    214 	syncNode->antecedents[0] = blockNode;
    215 	syncNode->antType[0] = rf_control;
    216 
    217 	/* connect the Rod nodes to the syncNode */
    218 	for (i = 0; i < nRodNodes; i++) {
    219 		rodNodes[i].succedents[0] = syncNode;
    220 		syncNode->antecedents[1 + i] = &rodNodes[i];
    221 		syncNode->antType[1 + i] = rf_control;
    222 	}
    223 
    224 	/* connect the sync node to the xor node */
    225 	RF_ASSERT(syncNode->numSuccedents == nWndNodes + 1);
    226 	RF_ASSERT(xorNode->numAntecedents == 1);
    227 	syncNode->succedents[0] = xorNode;
    228 	xorNode->antecedents[0] = syncNode;
    229 	xorNode->antType[0] = rf_trueData;	/* carry forward from sync */
    230 
    231 	/* connect the sync node to the Wnd nodes */
    232 	for (i = 0; i < nWndNodes; i++) {
    233 		RF_ASSERT(wndNodes->numAntecedents == 1);
    234 		syncNode->succedents[1 + i] = &wndNodes[i];
    235 		wndNodes[i].antecedents[0] = syncNode;
    236 		wndNodes[i].antType[0] = rf_control;
    237 	}
    238 
    239 	/* connect the xor node to the Lpo node */
    240 	RF_ASSERT(xorNode->numSuccedents == 1);
    241 	RF_ASSERT(lpoNode->numAntecedents == 1);
    242 	xorNode->succedents[0] = lpoNode;
    243 	lpoNode->antecedents[0] = xorNode;
    244 	lpoNode->antType[0] = rf_trueData;
    245 
    246 	/* connect the Wnd nodes to the unblock node */
    247 	RF_ASSERT(unblockNode->numAntecedents == nWndNodes + 1);
    248 	for (i = 0; i < nWndNodes; i++) {
    249 		RF_ASSERT(wndNodes->numSuccedents == 1);
    250 		wndNodes[i].succedents[0] = unblockNode;
    251 		unblockNode->antecedents[i] = &wndNodes[i];
    252 		unblockNode->antType[i] = rf_control;
    253 	}
    254 
    255 	/* connect the Lpo node to the unblock node */
    256 	RF_ASSERT(lpoNode->numSuccedents == 1);
    257 	lpoNode->succedents[0] = unblockNode;
    258 	unblockNode->antecedents[nWndNodes] = lpoNode;
    259 	unblockNode->antType[nWndNodes] = rf_control;
    260 
    261 	/* connect unblock node to terminator */
    262 	RF_ASSERT(unblockNode->numSuccedents == 1);
    263 	RF_ASSERT(termNode->numAntecedents == 1);
    264 	RF_ASSERT(termNode->numSuccedents == 0);
    265 	unblockNode->succedents[0] = termNode;
    266 	termNode->antecedents[0] = unblockNode;
    267 	termNode->antType[0] = rf_control;
    268 }
    269 
    270 
    271 
    272 
    273 /******************************************************************************
    274  *
    275  * creates a DAG to perform a small-write operation (either raid 5 or pq), which is as follows:
    276  *
    277  *                                     Header
    278  *                                       |
    279  *                                     Block
    280  *                                 / |  ... \   \
    281  *                                /  |       \   \
    282  *                             Rod  Rod      Rod  Rop
    283  *                             | \ /| \    / |  \/ |
    284  *                             |    |        |  /\ |
    285  *                             Wnd  Wnd      Wnd   X
    286  *                              |    \       /     |
    287  *                              |     \     /      |
    288  *                               \     \   /      Lpo
    289  *                                \     \ /       /
    290  *                                 +-> Unblock <-+
    291  *                                       |
    292  *                                       T
    293  *
    294  *
    295  * R = Read, W = Write, X = Xor, o = old, n = new, d = data, p = parity.
    296  * When the access spans a stripe unit boundary and is less than one SU in size, there will
    297  * be two Rop -- X -- Wnp branches.  I call this the "double-XOR" case.
    298  * The second output from each Rod node goes to the X node.  In the double-XOR
    299  * case, there are exactly 2 Rod nodes, and each sends one output to one X node.
    300  * There is one Rod -- Wnd -- T branch for each stripe unit being updated.
    301  *
    302  * The block and unblock nodes are unused.  See comment above CreateFaultFreeReadDAG.
    303  *
    304  * Note:  this DAG ignores all the optimizations related to making the RMWs atomic.
    305  *        it also has the nasty property that none of the buffers allocated for reading
    306  *        old data & parity can be freed until the XOR node fires.  Need to fix this.
    307  *
    308  * A null qfuncs indicates single fault tolerant
    309  *****************************************************************************/
    310 
    311 void
    312 rf_CommonCreateParityLoggingSmallWriteDAG(
    313     RF_Raid_t * raidPtr,
    314     RF_AccessStripeMap_t * asmap,
    315     RF_DagHeader_t * dag_h,
    316     void *bp,
    317     RF_RaidAccessFlags_t flags,
    318     RF_AllocListElem_t * allocList,
    319     RF_RedFuncs_t * pfuncs,
    320     RF_RedFuncs_t * qfuncs)
    321 {
    322 	RF_DagNode_t *xorNodes, *blockNode, *unblockNode, *nodes;
    323 	RF_DagNode_t *readDataNodes, *readParityNodes;
    324 	RF_DagNode_t *writeDataNodes, *lpuNodes;
    325 	RF_DagNode_t *unlockDataNodes = NULL, *termNode;
    326 	RF_PhysDiskAddr_t *pda = asmap->physInfo;
    327 	int     numDataNodes = asmap->numStripeUnitsAccessed;
    328 	int     numParityNodes = (asmap->parityInfo->next) ? 2 : 1;
    329 	int     i, j, nNodes, totalNumNodes;
    330 	RF_ReconUnitNum_t which_ru;
    331 	int     (*func) (RF_DagNode_t * node), (*undoFunc) (RF_DagNode_t * node);
    332 	int     (*qfunc) (RF_DagNode_t * node);
    333 	char   *name, *qname;
    334 	RF_StripeNum_t parityStripeID = rf_RaidAddressToParityStripeID(&(raidPtr->Layout), asmap->raidAddress, &which_ru);
    335 #ifdef RAID_DIAGNOSTIC
    336 	long    nfaults = qfuncs ? 2 : 1;
    337 #endif /* RAID_DIAGNOSTIC */
    338 	int     lu_flag = (rf_enableAtomicRMW) ? 1 : 0;	/* lock/unlock flag */
    339 
    340 	if (rf_dagDebug)
    341 		printf("[Creating parity-logging small-write DAG]\n");
    342 	RF_ASSERT(numDataNodes > 0);
    343 	RF_ASSERT(nfaults == 1);
    344 	dag_h->creator = "ParityLoggingSmallWriteDAG";
    345 
    346 	/* DAG creation occurs in three steps: 1. count the number of nodes in
    347 	 * the DAG 2. create the nodes 3. initialize the nodes 4. connect the
    348 	 * nodes */
    349 
    350 	/* Step 1. compute number of nodes in the graph */
    351 
    352 	/* number of nodes: a read and write for each data unit a redundancy
    353 	 * computation node for each parity node a read and Lpu for each
    354 	 * parity unit a block and unblock node (2) a terminator node if
    355 	 * atomic RMW an unlock node for each data unit, redundancy unit */
    356 	totalNumNodes = (2 * numDataNodes) + numParityNodes + (2 * numParityNodes) + 3;
    357 	if (lu_flag)
    358 		totalNumNodes += numDataNodes;
    359 
    360 	nNodes = numDataNodes + numParityNodes;
    361 
    362 	dag_h->numCommitNodes = numDataNodes + numParityNodes;
    363 	dag_h->numCommits = 0;
    364 	dag_h->numSuccedents = 1;
    365 
    366 	/* Step 2. create the nodes */
    367 	RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t), (RF_DagNode_t *), allocList);
    368 	i = 0;
    369 	blockNode = &nodes[i];
    370 	i += 1;
    371 	unblockNode = &nodes[i];
    372 	i += 1;
    373 	readDataNodes = &nodes[i];
    374 	i += numDataNodes;
    375 	readParityNodes = &nodes[i];
    376 	i += numParityNodes;
    377 	writeDataNodes = &nodes[i];
    378 	i += numDataNodes;
    379 	lpuNodes = &nodes[i];
    380 	i += numParityNodes;
    381 	xorNodes = &nodes[i];
    382 	i += numParityNodes;
    383 	termNode = &nodes[i];
    384 	i += 1;
    385 	if (lu_flag) {
    386 		unlockDataNodes = &nodes[i];
    387 		i += numDataNodes;
    388 	}
    389 	RF_ASSERT(i == totalNumNodes);
    390 
    391 	/* Step 3. initialize the nodes */
    392 	/* initialize block node (Nil) */
    393 	rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nNodes, 0, 0, 0, dag_h, "Nil", allocList);
    394 
    395 	/* initialize unblock node (Nil) */
    396 	rf_InitNode(unblockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nNodes, 0, 0, dag_h, "Nil", allocList);
    397 
    398 	/* initialize terminatory node (Trm) */
    399 	rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
    400 
    401 	/* initialize nodes which read old data (Rod) */
    402 	for (i = 0; i < numDataNodes; i++) {
    403 		rf_InitNode(&readDataNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rod", allocList);
    404 		RF_ASSERT(pda != NULL);
    405 		readDataNodes[i].params[0].p = pda;	/* physical disk addr
    406 							 * desc */
    407 		readDataNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda, allocList);	/* buffer to hold old
    408 												 * data */
    409 		readDataNodes[i].params[2].v = parityStripeID;
    410 		readDataNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, lu_flag, 0, which_ru);
    411 		pda = pda->next;
    412 		readDataNodes[i].propList[0] = NULL;
    413 		readDataNodes[i].propList[1] = NULL;
    414 	}
    415 
    416 	/* initialize nodes which read old parity (Rop) */
    417 	pda = asmap->parityInfo;
    418 	i = 0;
    419 	for (i = 0; i < numParityNodes; i++) {
    420 		RF_ASSERT(pda != NULL);
    421 		rf_InitNode(&readParityNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rop", allocList);
    422 		readParityNodes[i].params[0].p = pda;
    423 		readParityNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda, allocList);	/* buffer to hold old
    424 													 * parity */
    425 		readParityNodes[i].params[2].v = parityStripeID;
    426 		readParityNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
    427 		readParityNodes[i].propList[0] = NULL;
    428 		pda = pda->next;
    429 	}
    430 
    431 	/* initialize nodes which write new data (Wnd) */
    432 	pda = asmap->physInfo;
    433 	for (i = 0; i < numDataNodes; i++) {
    434 		RF_ASSERT(pda != NULL);
    435 		rf_InitNode(&writeDataNodes[i], rf_wait, RF_TRUE, rf_DiskWriteFunc, rf_DiskWriteUndoFunc, rf_GenericWakeupFunc, 1, nNodes, 4, 0, dag_h, "Wnd", allocList);
    436 		writeDataNodes[i].params[0].p = pda;	/* physical disk addr
    437 							 * desc */
    438 		writeDataNodes[i].params[1].p = pda->bufPtr;	/* buffer holding new
    439 								 * data to be written */
    440 		writeDataNodes[i].params[2].v = parityStripeID;
    441 		writeDataNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
    442 
    443 		if (lu_flag) {
    444 			/* initialize node to unlock the disk queue */
    445 			rf_InitNode(&unlockDataNodes[i], rf_wait, RF_FALSE, rf_DiskUnlockFunc, rf_DiskUnlockUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Und", allocList);
    446 			unlockDataNodes[i].params[0].p = pda;	/* physical disk addr
    447 								 * desc */
    448 			unlockDataNodes[i].params[1].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, lu_flag, which_ru);
    449 		}
    450 		pda = pda->next;
    451 	}
    452 
    453 
    454 	/* initialize nodes which compute new parity */
    455 	/* we use the simple XOR func in the double-XOR case, and when we're
    456 	 * accessing only a portion of one stripe unit. the distinction
    457 	 * between the two is that the regular XOR func assumes that the
    458 	 * targbuf is a full SU in size, and examines the pda associated with
    459 	 * the buffer to decide where within the buffer to XOR the data,
    460 	 * whereas the simple XOR func just XORs the data into the start of
    461 	 * the buffer. */
    462 	if ((numParityNodes == 2) || ((numDataNodes == 1) && (asmap->totalSectorsAccessed < raidPtr->Layout.sectorsPerStripeUnit))) {
    463 		func = pfuncs->simple;
    464 		undoFunc = rf_NullNodeUndoFunc;
    465 		name = pfuncs->SimpleName;
    466 		if (qfuncs) {
    467 			qfunc = qfuncs->simple;
    468 			qname = qfuncs->SimpleName;
    469 		}
    470 	} else {
    471 		func = pfuncs->regular;
    472 		undoFunc = rf_NullNodeUndoFunc;
    473 		name = pfuncs->RegularName;
    474 		if (qfuncs) {
    475 			qfunc = qfuncs->regular;
    476 			qname = qfuncs->RegularName;
    477 		}
    478 	}
    479 	/* initialize the xor nodes: params are {pda,buf} from {Rod,Wnd,Rop}
    480 	 * nodes, and raidPtr  */
    481 	if (numParityNodes == 2) {	/* double-xor case */
    482 		for (i = 0; i < numParityNodes; i++) {
    483 			rf_InitNode(&xorNodes[i], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, 7, 1, dag_h, name, allocList);	/* no wakeup func for
    484 																	 * xor */
    485 			xorNodes[i].flags |= RF_DAGNODE_FLAG_YIELD;
    486 			xorNodes[i].params[0] = readDataNodes[i].params[0];
    487 			xorNodes[i].params[1] = readDataNodes[i].params[1];
    488 			xorNodes[i].params[2] = readParityNodes[i].params[0];
    489 			xorNodes[i].params[3] = readParityNodes[i].params[1];
    490 			xorNodes[i].params[4] = writeDataNodes[i].params[0];
    491 			xorNodes[i].params[5] = writeDataNodes[i].params[1];
    492 			xorNodes[i].params[6].p = raidPtr;
    493 			xorNodes[i].results[0] = readParityNodes[i].params[1].p;	/* use old parity buf as
    494 											 * target buf */
    495 		}
    496 	} else {
    497 		/* there is only one xor node in this case */
    498 		rf_InitNode(&xorNodes[0], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, (2 * (numDataNodes + numDataNodes + 1) + 1), 1, dag_h, name, allocList);
    499 		xorNodes[0].flags |= RF_DAGNODE_FLAG_YIELD;
    500 		for (i = 0; i < numDataNodes + 1; i++) {
    501 			/* set up params related to Rod and Rop nodes */
    502 			xorNodes[0].params[2 * i + 0] = readDataNodes[i].params[0];	/* pda */
    503 			xorNodes[0].params[2 * i + 1] = readDataNodes[i].params[1];	/* buffer pointer */
    504 		}
    505 		for (i = 0; i < numDataNodes; i++) {
    506 			/* set up params related to Wnd and Wnp nodes */
    507 			xorNodes[0].params[2 * (numDataNodes + 1 + i) + 0] = writeDataNodes[i].params[0];	/* pda */
    508 			xorNodes[0].params[2 * (numDataNodes + 1 + i) + 1] = writeDataNodes[i].params[1];	/* buffer pointer */
    509 		}
    510 		xorNodes[0].params[2 * (numDataNodes + numDataNodes + 1)].p = raidPtr;	/* xor node needs to get
    511 											 * at RAID information */
    512 		xorNodes[0].results[0] = readParityNodes[0].params[1].p;
    513 	}
    514 
    515 	/* initialize the log node(s) */
    516 	pda = asmap->parityInfo;
    517 	for (i = 0; i < numParityNodes; i++) {
    518 		RF_ASSERT(pda);
    519 		rf_InitNode(&lpuNodes[i], rf_wait, RF_FALSE, rf_ParityLogUpdateFunc, rf_ParityLogUpdateUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Lpu", allocList);
    520 		lpuNodes[i].params[0].p = pda;	/* PhysDiskAddr of parity */
    521 		lpuNodes[i].params[1].p = xorNodes[i].results[0];	/* buffer pointer to
    522 									 * parity */
    523 		pda = pda->next;
    524 	}
    525 
    526 
    527 	/* Step 4. connect the nodes */
    528 
    529 	/* connect header to block node */
    530 	RF_ASSERT(dag_h->numSuccedents == 1);
    531 	RF_ASSERT(blockNode->numAntecedents == 0);
    532 	dag_h->succedents[0] = blockNode;
    533 
    534 	/* connect block node to read old data nodes */
    535 	RF_ASSERT(blockNode->numSuccedents == (numDataNodes + numParityNodes));
    536 	for (i = 0; i < numDataNodes; i++) {
    537 		blockNode->succedents[i] = &readDataNodes[i];
    538 		RF_ASSERT(readDataNodes[i].numAntecedents == 1);
    539 		readDataNodes[i].antecedents[0] = blockNode;
    540 		readDataNodes[i].antType[0] = rf_control;
    541 	}
    542 
    543 	/* connect block node to read old parity nodes */
    544 	for (i = 0; i < numParityNodes; i++) {
    545 		blockNode->succedents[numDataNodes + i] = &readParityNodes[i];
    546 		RF_ASSERT(readParityNodes[i].numAntecedents == 1);
    547 		readParityNodes[i].antecedents[0] = blockNode;
    548 		readParityNodes[i].antType[0] = rf_control;
    549 	}
    550 
    551 	/* connect read old data nodes to write new data nodes */
    552 	for (i = 0; i < numDataNodes; i++) {
    553 		RF_ASSERT(readDataNodes[i].numSuccedents == numDataNodes + numParityNodes);
    554 		for (j = 0; j < numDataNodes; j++) {
    555 			RF_ASSERT(writeDataNodes[j].numAntecedents == numDataNodes + numParityNodes);
    556 			readDataNodes[i].succedents[j] = &writeDataNodes[j];
    557 			writeDataNodes[j].antecedents[i] = &readDataNodes[i];
    558 			if (i == j)
    559 				writeDataNodes[j].antType[i] = rf_antiData;
    560 			else
    561 				writeDataNodes[j].antType[i] = rf_control;
    562 		}
    563 	}
    564 
    565 	/* connect read old data nodes to xor nodes */
    566 	for (i = 0; i < numDataNodes; i++)
    567 		for (j = 0; j < numParityNodes; j++) {
    568 			RF_ASSERT(xorNodes[j].numAntecedents == numDataNodes + numParityNodes);
    569 			readDataNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
    570 			xorNodes[j].antecedents[i] = &readDataNodes[i];
    571 			xorNodes[j].antType[i] = rf_trueData;
    572 		}
    573 
    574 	/* connect read old parity nodes to write new data nodes */
    575 	for (i = 0; i < numParityNodes; i++) {
    576 		RF_ASSERT(readParityNodes[i].numSuccedents == numDataNodes + numParityNodes);
    577 		for (j = 0; j < numDataNodes; j++) {
    578 			readParityNodes[i].succedents[j] = &writeDataNodes[j];
    579 			writeDataNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
    580 			writeDataNodes[j].antType[numDataNodes + i] = rf_control;
    581 		}
    582 	}
    583 
    584 	/* connect read old parity nodes to xor nodes */
    585 	for (i = 0; i < numParityNodes; i++)
    586 		for (j = 0; j < numParityNodes; j++) {
    587 			readParityNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
    588 			xorNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
    589 			xorNodes[j].antType[numDataNodes + i] = rf_trueData;
    590 		}
    591 
    592 	/* connect xor nodes to write new parity nodes */
    593 	for (i = 0; i < numParityNodes; i++) {
    594 		RF_ASSERT(xorNodes[i].numSuccedents == 1);
    595 		RF_ASSERT(lpuNodes[i].numAntecedents == 1);
    596 		xorNodes[i].succedents[0] = &lpuNodes[i];
    597 		lpuNodes[i].antecedents[0] = &xorNodes[i];
    598 		lpuNodes[i].antType[0] = rf_trueData;
    599 	}
    600 
    601 	for (i = 0; i < numDataNodes; i++) {
    602 		if (lu_flag) {
    603 			/* connect write new data nodes to unlock nodes */
    604 			RF_ASSERT(writeDataNodes[i].numSuccedents == 1);
    605 			RF_ASSERT(unlockDataNodes[i].numAntecedents == 1);
    606 			writeDataNodes[i].succedents[0] = &unlockDataNodes[i];
    607 			unlockDataNodes[i].antecedents[0] = &writeDataNodes[i];
    608 			unlockDataNodes[i].antType[0] = rf_control;
    609 
    610 			/* connect unlock nodes to unblock node */
    611 			RF_ASSERT(unlockDataNodes[i].numSuccedents == 1);
    612 			RF_ASSERT(unblockNode->numAntecedents == (numDataNodes + (nfaults * numParityNodes)));
    613 			unlockDataNodes[i].succedents[0] = unblockNode;
    614 			unblockNode->antecedents[i] = &unlockDataNodes[i];
    615 			unblockNode->antType[i] = rf_control;
    616 		} else {
    617 			/* connect write new data nodes to unblock node */
    618 			RF_ASSERT(writeDataNodes[i].numSuccedents == 1);
    619 			RF_ASSERT(unblockNode->numAntecedents == (numDataNodes + (nfaults * numParityNodes)));
    620 			writeDataNodes[i].succedents[0] = unblockNode;
    621 			unblockNode->antecedents[i] = &writeDataNodes[i];
    622 			unblockNode->antType[i] = rf_control;
    623 		}
    624 	}
    625 
    626 	/* connect write new parity nodes to unblock node */
    627 	for (i = 0; i < numParityNodes; i++) {
    628 		RF_ASSERT(lpuNodes[i].numSuccedents == 1);
    629 		lpuNodes[i].succedents[0] = unblockNode;
    630 		unblockNode->antecedents[numDataNodes + i] = &lpuNodes[i];
    631 		unblockNode->antType[numDataNodes + i] = rf_control;
    632 	}
    633 
    634 	/* connect unblock node to terminator */
    635 	RF_ASSERT(unblockNode->numSuccedents == 1);
    636 	RF_ASSERT(termNode->numAntecedents == 1);
    637 	RF_ASSERT(termNode->numSuccedents == 0);
    638 	unblockNode->succedents[0] = termNode;
    639 	termNode->antecedents[0] = unblockNode;
    640 	termNode->antType[0] = rf_control;
    641 }
    642 
    643 
    644 void
    645 rf_CreateParityLoggingSmallWriteDAG(
    646     RF_Raid_t * raidPtr,
    647     RF_AccessStripeMap_t * asmap,
    648     RF_DagHeader_t * dag_h,
    649     void *bp,
    650     RF_RaidAccessFlags_t flags,
    651     RF_AllocListElem_t * allocList,
    652     RF_RedFuncs_t * pfuncs,
    653     RF_RedFuncs_t * qfuncs)
    654 {
    655 	dag_h->creator = "ParityLoggingSmallWriteDAG";
    656 	rf_CommonCreateParityLoggingSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_xorFuncs, NULL);
    657 }
    658 
    659 
    660 void
    661 rf_CreateParityLoggingLargeWriteDAG(
    662     RF_Raid_t * raidPtr,
    663     RF_AccessStripeMap_t * asmap,
    664     RF_DagHeader_t * dag_h,
    665     void *bp,
    666     RF_RaidAccessFlags_t flags,
    667     RF_AllocListElem_t * allocList,
    668     int nfaults,
    669     int (*redFunc) (RF_DagNode_t *))
    670 {
    671 	dag_h->creator = "ParityLoggingSmallWriteDAG";
    672 	rf_CommonCreateParityLoggingLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularXorFunc);
    673 }
    674 #endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
    675