xref: /netbsd-src/sys/dev/raidframe/rf_parityloggingdags.c (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 /*	$NetBSD: rf_parityloggingdags.c,v 1.21 2014/03/23 09:30:59 christos 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@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 /*
30   DAGs specific to parity logging are created here
31  */
32 
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: rf_parityloggingdags.c,v 1.21 2014/03/23 09:30:59 christos Exp $");
35 
36 #ifdef _KERNEL_OPT
37 #include "opt_raid_diagnostic.h"
38 #endif
39 
40 #include "rf_archs.h"
41 
42 #if RF_INCLUDE_PARITYLOGGING > 0
43 
44 #include <dev/raidframe/raidframevar.h>
45 
46 #include "rf_raid.h"
47 #include "rf_dag.h"
48 #include "rf_dagutils.h"
49 #include "rf_dagfuncs.h"
50 #include "rf_debugMem.h"
51 #include "rf_paritylog.h"
52 #include "rf_general.h"
53 
54 #include "rf_parityloggingdags.h"
55 
56 /******************************************************************************
57  *
58  * creates a DAG to perform a large-write operation:
59  *
60  *         / Rod \     / Wnd \
61  * H -- NIL- Rod - NIL - Wnd ------ NIL - T
62  *         \ Rod /     \ Xor - Lpo /
63  *
64  * The writes are not done until the reads complete because if they were done in
65  * parallel, a failure on one of the reads could leave the parity in an inconsistent
66  * state, so that the retry with a new DAG would produce erroneous parity.
67  *
68  * Note:  this DAG has the nasty property that none of the buffers allocated for reading
69  *        old data can be freed until the XOR node fires.  Need to fix this.
70  *
71  * The last two arguments are the number of faults tolerated, and function for the
72  * redundancy calculation. The undo for the redundancy calc is assumed to be null
73  *
74  *****************************************************************************/
75 
76 void
77 rf_CommonCreateParityLoggingLargeWriteDAG(
78     RF_Raid_t * raidPtr,
79     RF_AccessStripeMap_t * asmap,
80     RF_DagHeader_t * dag_h,
81     void *bp,
82     RF_RaidAccessFlags_t flags,
83     RF_AllocListElem_t * allocList,
84     int nfaults,
85     int (*redFunc) (RF_DagNode_t *))
86 {
87 	RF_DagNode_t *nodes, *wndNodes, *rodNodes = NULL, *syncNode, *xorNode,
88 	       *lpoNode, *blockNode, *unblockNode, *termNode;
89 	int     nWndNodes, nRodNodes, i;
90 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
91 	RF_AccessStripeMapHeader_t *new_asm_h[2];
92 	int     nodeNum, asmNum;
93 	RF_ReconUnitNum_t which_ru;
94 	char   *sosBuffer, *eosBuffer;
95 	RF_PhysDiskAddr_t *pda;
96 	RF_StripeNum_t parityStripeID = rf_RaidAddressToParityStripeID(&(raidPtr->Layout), asmap->raidAddress, &which_ru);
97 
98 	if (rf_dagDebug)
99 		printf("[Creating parity-logging large-write DAG]\n");
100 	RF_ASSERT(nfaults == 1);/* this arch only single fault tolerant */
101 	dag_h->creator = "ParityLoggingLargeWriteDAG";
102 
103 	/* alloc the Wnd nodes, the xor node, and the Lpo node */
104 	nWndNodes = asmap->numStripeUnitsAccessed;
105 	RF_MallocAndAdd(nodes, (nWndNodes + 6) * sizeof(RF_DagNode_t),
106 			(RF_DagNode_t *), allocList);
107 	i = 0;
108 	wndNodes = &nodes[i];
109 	i += nWndNodes;
110 	xorNode = &nodes[i];
111 	i += 1;
112 	lpoNode = &nodes[i];
113 	i += 1;
114 	blockNode = &nodes[i];
115 	i += 1;
116 	syncNode = &nodes[i];
117 	i += 1;
118 	unblockNode = &nodes[i];
119 	i += 1;
120 	termNode = &nodes[i];
121 	i += 1;
122 
123 	dag_h->numCommitNodes = nWndNodes + 1;
124 	dag_h->numCommits = 0;
125 	dag_h->numSuccedents = 1;
126 
127 	rf_MapUnaccessedPortionOfStripe(raidPtr, layoutPtr, asmap, dag_h, new_asm_h, &nRodNodes, &sosBuffer, &eosBuffer, allocList);
128 	if (nRodNodes > 0)
129 		RF_MallocAndAdd(rodNodes, nRodNodes * sizeof(RF_DagNode_t),
130 				(RF_DagNode_t *), allocList);
131 
132 	/* begin node initialization */
133 	rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nRodNodes + 1, 0, 0, 0, dag_h, "Nil", allocList);
134 	rf_InitNode(unblockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nWndNodes + 1, 0, 0, dag_h, "Nil", allocList);
135 	rf_InitNode(syncNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nWndNodes + 1, nRodNodes + 1, 0, 0, dag_h, "Nil", allocList);
136 	rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
137 
138 	/* initialize the Rod nodes */
139 	for (nodeNum = asmNum = 0; asmNum < 2; asmNum++) {
140 		if (new_asm_h[asmNum]) {
141 			pda = new_asm_h[asmNum]->stripeMap->physInfo;
142 			while (pda) {
143 				rf_InitNode(&rodNodes[nodeNum], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, 1, 1, 4, 0, dag_h, "Rod", allocList);
144 				rodNodes[nodeNum].params[0].p = pda;
145 				rodNodes[nodeNum].params[1].p = pda->bufPtr;
146 				rodNodes[nodeNum].params[2].v = parityStripeID;
147 				rodNodes[nodeNum].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, which_ru);
148 				nodeNum++;
149 				pda = pda->next;
150 			}
151 		}
152 	}
153 	RF_ASSERT(nodeNum == nRodNodes);
154 
155 	/* initialize the wnd nodes */
156 	pda = asmap->physInfo;
157 	for (i = 0; i < nWndNodes; i++) {
158 		rf_InitNode(&wndNodes[i], rf_wait, RF_TRUE, rf_DiskWriteFunc, rf_DiskWriteUndoFunc, rf_GenericWakeupFunc, 1, 1, 4, 0, dag_h, "Wnd", allocList);
159 		RF_ASSERT(pda != NULL);
160 		wndNodes[i].params[0].p = pda;
161 		wndNodes[i].params[1].p = pda->bufPtr;
162 		wndNodes[i].params[2].v = parityStripeID;
163 		wndNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, which_ru);
164 		pda = pda->next;
165 	}
166 
167 	/* initialize the redundancy node */
168 	rf_InitNode(xorNode, rf_wait, RF_TRUE, redFunc, rf_NullNodeUndoFunc, NULL, 1, 1, 2 * (nWndNodes + nRodNodes) + 1, 1, dag_h, "Xr ", allocList);
169 	xorNode->flags |= RF_DAGNODE_FLAG_YIELD;
170 	for (i = 0; i < nWndNodes; i++) {
171 		xorNode->params[2 * i + 0] = wndNodes[i].params[0];	/* pda */
172 		xorNode->params[2 * i + 1] = wndNodes[i].params[1];	/* buf ptr */
173 	}
174 	for (i = 0; i < nRodNodes; i++) {
175 		xorNode->params[2 * (nWndNodes + i) + 0] = rodNodes[i].params[0];	/* pda */
176 		xorNode->params[2 * (nWndNodes + i) + 1] = rodNodes[i].params[1];	/* buf ptr */
177 	}
178 	xorNode->params[2 * (nWndNodes + nRodNodes)].p = raidPtr;	/* xor node needs to get
179 									 * at RAID information */
180 
181 	/* look for an Rod node that reads a complete SU.  If none, alloc a
182 	 * buffer to receive the parity info. Note that we can't use a new
183 	 * data buffer because it will not have gotten written when the xor
184 	 * occurs. */
185 	for (i = 0; i < nRodNodes; i++)
186 		if (((RF_PhysDiskAddr_t *) rodNodes[i].params[0].p)->numSector == raidPtr->Layout.sectorsPerStripeUnit)
187 			break;
188 	if (i == nRodNodes) {
189 		RF_MallocAndAdd(xorNode->results[0],
190 				rf_RaidAddressToByte(raidPtr, raidPtr->Layout.sectorsPerStripeUnit), (void *), allocList);
191 	} else {
192 		xorNode->results[0] = rodNodes[i].params[1].p;
193 	}
194 
195 	/* initialize the Lpo node */
196 	rf_InitNode(lpoNode, rf_wait, RF_FALSE, rf_ParityLogOverwriteFunc, rf_ParityLogOverwriteUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Lpo", allocList);
197 
198 	lpoNode->params[0].p = asmap->parityInfo;
199 	lpoNode->params[1].p = xorNode->results[0];
200 	RF_ASSERT(asmap->parityInfo->next == NULL);	/* parityInfo must
201 							 * describe entire
202 							 * parity unit */
203 
204 	/* connect nodes to form graph */
205 
206 	/* connect dag header to block node */
207 	RF_ASSERT(dag_h->numSuccedents == 1);
208 	RF_ASSERT(blockNode->numAntecedents == 0);
209 	dag_h->succedents[0] = blockNode;
210 
211 	/* connect the block node to the Rod nodes */
212 	RF_ASSERT(blockNode->numSuccedents == nRodNodes + 1);
213 	for (i = 0; i < nRodNodes; i++) {
214 		RF_ASSERT(rodNodes[i].numAntecedents == 1);
215 		blockNode->succedents[i] = &rodNodes[i];
216 		rodNodes[i].antecedents[0] = blockNode;
217 		rodNodes[i].antType[0] = rf_control;
218 	}
219 
220 	/* connect the block node to the sync node */
221 	/* necessary if nRodNodes == 0 */
222 	RF_ASSERT(syncNode->numAntecedents == nRodNodes + 1);
223 	blockNode->succedents[nRodNodes] = syncNode;
224 	syncNode->antecedents[0] = blockNode;
225 	syncNode->antType[0] = rf_control;
226 
227 	/* connect the Rod nodes to the syncNode */
228 	for (i = 0; i < nRodNodes; i++) {
229 		rodNodes[i].succedents[0] = syncNode;
230 		syncNode->antecedents[1 + i] = &rodNodes[i];
231 		syncNode->antType[1 + i] = rf_control;
232 	}
233 
234 	/* connect the sync node to the xor node */
235 	RF_ASSERT(syncNode->numSuccedents == nWndNodes + 1);
236 	RF_ASSERT(xorNode->numAntecedents == 1);
237 	syncNode->succedents[0] = xorNode;
238 	xorNode->antecedents[0] = syncNode;
239 	xorNode->antType[0] = rf_trueData;	/* carry forward from sync */
240 
241 	/* connect the sync node to the Wnd nodes */
242 	for (i = 0; i < nWndNodes; i++) {
243 		RF_ASSERT(wndNodes->numAntecedents == 1);
244 		syncNode->succedents[1 + i] = &wndNodes[i];
245 		wndNodes[i].antecedents[0] = syncNode;
246 		wndNodes[i].antType[0] = rf_control;
247 	}
248 
249 	/* connect the xor node to the Lpo node */
250 	RF_ASSERT(xorNode->numSuccedents == 1);
251 	RF_ASSERT(lpoNode->numAntecedents == 1);
252 	xorNode->succedents[0] = lpoNode;
253 	lpoNode->antecedents[0] = xorNode;
254 	lpoNode->antType[0] = rf_trueData;
255 
256 	/* connect the Wnd nodes to the unblock node */
257 	RF_ASSERT(unblockNode->numAntecedents == nWndNodes + 1);
258 	for (i = 0; i < nWndNodes; i++) {
259 		RF_ASSERT(wndNodes->numSuccedents == 1);
260 		wndNodes[i].succedents[0] = unblockNode;
261 		unblockNode->antecedents[i] = &wndNodes[i];
262 		unblockNode->antType[i] = rf_control;
263 	}
264 
265 	/* connect the Lpo node to the unblock node */
266 	RF_ASSERT(lpoNode->numSuccedents == 1);
267 	lpoNode->succedents[0] = unblockNode;
268 	unblockNode->antecedents[nWndNodes] = lpoNode;
269 	unblockNode->antType[nWndNodes] = rf_control;
270 
271 	/* connect unblock node to terminator */
272 	RF_ASSERT(unblockNode->numSuccedents == 1);
273 	RF_ASSERT(termNode->numAntecedents == 1);
274 	RF_ASSERT(termNode->numSuccedents == 0);
275 	unblockNode->succedents[0] = termNode;
276 	termNode->antecedents[0] = unblockNode;
277 	termNode->antType[0] = rf_control;
278 }
279 
280 
281 
282 
283 /******************************************************************************
284  *
285  * creates a DAG to perform a small-write operation (either raid 5 or pq), which is as follows:
286  *
287  *                                     Header
288  *                                       |
289  *                                     Block
290  *                                 / |  ... \   \
291  *                                /  |       \   \
292  *                             Rod  Rod      Rod  Rop
293  *                             | \ /| \    / |  \/ |
294  *                             |    |        |  /\ |
295  *                             Wnd  Wnd      Wnd   X
296  *                              |    \       /     |
297  *                              |     \     /      |
298  *                               \     \   /      Lpo
299  *                                \     \ /       /
300  *                                 +-> Unblock <-+
301  *                                       |
302  *                                       T
303  *
304  *
305  * R = Read, W = Write, X = Xor, o = old, n = new, d = data, p = parity.
306  * When the access spans a stripe unit boundary and is less than one SU in size, there will
307  * be two Rop -- X -- Wnp branches.  I call this the "double-XOR" case.
308  * The second output from each Rod node goes to the X node.  In the double-XOR
309  * case, there are exactly 2 Rod nodes, and each sends one output to one X node.
310  * There is one Rod -- Wnd -- T branch for each stripe unit being updated.
311  *
312  * The block and unblock nodes are unused.  See comment above CreateFaultFreeReadDAG.
313  *
314  * Note:  this DAG ignores all the optimizations related to making the RMWs atomic.
315  *        it also has the nasty property that none of the buffers allocated for reading
316  *        old data & parity can be freed until the XOR node fires.  Need to fix this.
317  *
318  * A null qfuncs indicates single fault tolerant
319  *****************************************************************************/
320 
321 void
322 rf_CommonCreateParityLoggingSmallWriteDAG(
323     RF_Raid_t * raidPtr,
324     RF_AccessStripeMap_t * asmap,
325     RF_DagHeader_t * dag_h,
326     void *bp,
327     RF_RaidAccessFlags_t flags,
328     RF_AllocListElem_t * allocList,
329     const RF_RedFuncs_t * pfuncs,
330     const RF_RedFuncs_t * qfuncs)
331 {
332 	RF_DagNode_t *xorNodes, *blockNode, *unblockNode, *nodes;
333 	RF_DagNode_t *readDataNodes, *readParityNodes;
334 	RF_DagNode_t *writeDataNodes, *lpuNodes;
335 	RF_DagNode_t *termNode;
336 	RF_PhysDiskAddr_t *pda = asmap->physInfo;
337 	int     numDataNodes = asmap->numStripeUnitsAccessed;
338 	int     numParityNodes = (asmap->parityInfo->next) ? 2 : 1;
339 	int     i, j, nNodes, totalNumNodes;
340 	RF_ReconUnitNum_t which_ru;
341 	int     (*func) (RF_DagNode_t * node), (*undoFunc) (RF_DagNode_t * node);
342 	const char   *name;
343 	RF_StripeNum_t parityStripeID = rf_RaidAddressToParityStripeID(&(raidPtr->Layout), asmap->raidAddress, &which_ru);
344 	long    nfaults __unused = qfuncs ? 2 : 1;
345 
346 	if (rf_dagDebug)
347 		printf("[Creating parity-logging small-write DAG]\n");
348 	RF_ASSERT(numDataNodes > 0);
349 	RF_ASSERT(nfaults == 1);
350 	dag_h->creator = "ParityLoggingSmallWriteDAG";
351 
352 	/* DAG creation occurs in three steps: 1. count the number of nodes in
353 	 * the DAG 2. create the nodes 3. initialize the nodes 4. connect the
354 	 * nodes */
355 
356 	/* Step 1. compute number of nodes in the graph */
357 
358 	/* number of nodes: a read and write for each data unit a redundancy
359 	 * computation node for each parity node a read and Lpu for each
360 	 * parity unit a block and unblock node (2) a terminator node if
361 	 * atomic RMW an unlock node for each data unit, redundancy unit */
362 	totalNumNodes = (2 * numDataNodes) + numParityNodes + (2 * numParityNodes) + 3;
363 
364 	nNodes = numDataNodes + numParityNodes;
365 
366 	dag_h->numCommitNodes = numDataNodes + numParityNodes;
367 	dag_h->numCommits = 0;
368 	dag_h->numSuccedents = 1;
369 
370 	/* Step 2. create the nodes */
371 	RF_MallocAndAdd(nodes, totalNumNodes * sizeof(RF_DagNode_t),
372 			(RF_DagNode_t *), allocList);
373 	i = 0;
374 	blockNode = &nodes[i];
375 	i += 1;
376 	unblockNode = &nodes[i];
377 	i += 1;
378 	readDataNodes = &nodes[i];
379 	i += numDataNodes;
380 	readParityNodes = &nodes[i];
381 	i += numParityNodes;
382 	writeDataNodes = &nodes[i];
383 	i += numDataNodes;
384 	lpuNodes = &nodes[i];
385 	i += numParityNodes;
386 	xorNodes = &nodes[i];
387 	i += numParityNodes;
388 	termNode = &nodes[i];
389 	i += 1;
390 
391 	RF_ASSERT(i == totalNumNodes);
392 
393 	/* Step 3. initialize the nodes */
394 	/* initialize block node (Nil) */
395 	rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nNodes, 0, 0, 0, dag_h, "Nil", allocList);
396 
397 	/* initialize unblock node (Nil) */
398 	rf_InitNode(unblockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nNodes, 0, 0, dag_h, "Nil", allocList);
399 
400 	/* initialize terminatory node (Trm) */
401 	rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
402 
403 	/* initialize nodes which read old data (Rod) */
404 	for (i = 0; i < numDataNodes; i++) {
405 		rf_InitNode(&readDataNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rod", allocList);
406 		RF_ASSERT(pda != NULL);
407 		readDataNodes[i].params[0].p = pda;	/* physical disk addr
408 							 * desc */
409 		readDataNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda->numSector << raidPtr->logBytesPerSector);	/* buffer to hold old data */
410 		readDataNodes[i].params[2].v = parityStripeID;
411 		readDataNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, which_ru);
412 		pda = pda->next;
413 		readDataNodes[i].propList[0] = NULL;
414 		readDataNodes[i].propList[1] = NULL;
415 	}
416 
417 	/* initialize nodes which read old parity (Rop) */
418 	pda = asmap->parityInfo;
419 	i = 0;
420 	for (i = 0; i < numParityNodes; i++) {
421 		RF_ASSERT(pda != NULL);
422 		rf_InitNode(&readParityNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rop", allocList);
423 		readParityNodes[i].params[0].p = pda;
424 		readParityNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda->numSector << raidPtr->logBytesPerSector);	/* buffer to hold old parity */
425 		readParityNodes[i].params[2].v = parityStripeID;
426 		readParityNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 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, which_ru);
442 
443 		pda = pda->next;
444 	}
445 
446 
447 	/* initialize nodes which compute new parity */
448 	/* we use the simple XOR func in the double-XOR case, and when we're
449 	 * accessing only a portion of one stripe unit. the distinction
450 	 * between the two is that the regular XOR func assumes that the
451 	 * targbuf is a full SU in size, and examines the pda associated with
452 	 * the buffer to decide where within the buffer to XOR the data,
453 	 * whereas the simple XOR func just XORs the data into the start of
454 	 * the buffer. */
455 	if ((numParityNodes == 2) || ((numDataNodes == 1) && (asmap->totalSectorsAccessed < raidPtr->Layout.sectorsPerStripeUnit))) {
456 		func = pfuncs->simple;
457 		undoFunc = rf_NullNodeUndoFunc;
458 		name = pfuncs->SimpleName;
459 	} else {
460 		func = pfuncs->regular;
461 		undoFunc = rf_NullNodeUndoFunc;
462 		name = pfuncs->RegularName;
463 	}
464 	/* initialize the xor nodes: params are {pda,buf} from {Rod,Wnd,Rop}
465 	 * nodes, and raidPtr  */
466 	if (numParityNodes == 2) {	/* double-xor case */
467 		for (i = 0; i < numParityNodes; i++) {
468 			rf_InitNode(&xorNodes[i], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, 7, 1, dag_h, name, allocList);	/* no wakeup func for
469 																	 * xor */
470 			xorNodes[i].flags |= RF_DAGNODE_FLAG_YIELD;
471 			xorNodes[i].params[0] = readDataNodes[i].params[0];
472 			xorNodes[i].params[1] = readDataNodes[i].params[1];
473 			xorNodes[i].params[2] = readParityNodes[i].params[0];
474 			xorNodes[i].params[3] = readParityNodes[i].params[1];
475 			xorNodes[i].params[4] = writeDataNodes[i].params[0];
476 			xorNodes[i].params[5] = writeDataNodes[i].params[1];
477 			xorNodes[i].params[6].p = raidPtr;
478 			xorNodes[i].results[0] = readParityNodes[i].params[1].p;	/* use old parity buf as
479 											 * target buf */
480 		}
481 	} else {
482 		/* there is only one xor node in this case */
483 		rf_InitNode(&xorNodes[0], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, (2 * (numDataNodes + numDataNodes + 1) + 1), 1, dag_h, name, allocList);
484 		xorNodes[0].flags |= RF_DAGNODE_FLAG_YIELD;
485 		for (i = 0; i < numDataNodes + 1; i++) {
486 			/* set up params related to Rod and Rop nodes */
487 			xorNodes[0].params[2 * i + 0] = readDataNodes[i].params[0];	/* pda */
488 			xorNodes[0].params[2 * i + 1] = readDataNodes[i].params[1];	/* buffer pointer */
489 		}
490 		for (i = 0; i < numDataNodes; i++) {
491 			/* set up params related to Wnd and Wnp nodes */
492 			xorNodes[0].params[2 * (numDataNodes + 1 + i) + 0] = writeDataNodes[i].params[0];	/* pda */
493 			xorNodes[0].params[2 * (numDataNodes + 1 + i) + 1] = writeDataNodes[i].params[1];	/* buffer pointer */
494 		}
495 		xorNodes[0].params[2 * (numDataNodes + numDataNodes + 1)].p = raidPtr;	/* xor node needs to get
496 											 * at RAID information */
497 		xorNodes[0].results[0] = readParityNodes[0].params[1].p;
498 	}
499 
500 	/* initialize the log node(s) */
501 	pda = asmap->parityInfo;
502 	for (i = 0; i < numParityNodes; i++) {
503 		RF_ASSERT(pda);
504 		rf_InitNode(&lpuNodes[i], rf_wait, RF_FALSE, rf_ParityLogUpdateFunc, rf_ParityLogUpdateUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Lpu", allocList);
505 		lpuNodes[i].params[0].p = pda;	/* PhysDiskAddr of parity */
506 		lpuNodes[i].params[1].p = xorNodes[i].results[0];	/* buffer pointer to
507 									 * parity */
508 		pda = pda->next;
509 	}
510 
511 
512 	/* Step 4. connect the nodes */
513 
514 	/* connect header to block node */
515 	RF_ASSERT(dag_h->numSuccedents == 1);
516 	RF_ASSERT(blockNode->numAntecedents == 0);
517 	dag_h->succedents[0] = blockNode;
518 
519 	/* connect block node to read old data nodes */
520 	RF_ASSERT(blockNode->numSuccedents == (numDataNodes + numParityNodes));
521 	for (i = 0; i < numDataNodes; i++) {
522 		blockNode->succedents[i] = &readDataNodes[i];
523 		RF_ASSERT(readDataNodes[i].numAntecedents == 1);
524 		readDataNodes[i].antecedents[0] = blockNode;
525 		readDataNodes[i].antType[0] = rf_control;
526 	}
527 
528 	/* connect block node to read old parity nodes */
529 	for (i = 0; i < numParityNodes; i++) {
530 		blockNode->succedents[numDataNodes + i] = &readParityNodes[i];
531 		RF_ASSERT(readParityNodes[i].numAntecedents == 1);
532 		readParityNodes[i].antecedents[0] = blockNode;
533 		readParityNodes[i].antType[0] = rf_control;
534 	}
535 
536 	/* connect read old data nodes to write new data nodes */
537 	for (i = 0; i < numDataNodes; i++) {
538 		RF_ASSERT(readDataNodes[i].numSuccedents == numDataNodes + numParityNodes);
539 		for (j = 0; j < numDataNodes; j++) {
540 			RF_ASSERT(writeDataNodes[j].numAntecedents == numDataNodes + numParityNodes);
541 			readDataNodes[i].succedents[j] = &writeDataNodes[j];
542 			writeDataNodes[j].antecedents[i] = &readDataNodes[i];
543 			if (i == j)
544 				writeDataNodes[j].antType[i] = rf_antiData;
545 			else
546 				writeDataNodes[j].antType[i] = rf_control;
547 		}
548 	}
549 
550 	/* connect read old data nodes to xor nodes */
551 	for (i = 0; i < numDataNodes; i++)
552 		for (j = 0; j < numParityNodes; j++) {
553 			RF_ASSERT(xorNodes[j].numAntecedents == numDataNodes + numParityNodes);
554 			readDataNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
555 			xorNodes[j].antecedents[i] = &readDataNodes[i];
556 			xorNodes[j].antType[i] = rf_trueData;
557 		}
558 
559 	/* connect read old parity nodes to write new data nodes */
560 	for (i = 0; i < numParityNodes; i++) {
561 		RF_ASSERT(readParityNodes[i].numSuccedents == numDataNodes + numParityNodes);
562 		for (j = 0; j < numDataNodes; j++) {
563 			readParityNodes[i].succedents[j] = &writeDataNodes[j];
564 			writeDataNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
565 			writeDataNodes[j].antType[numDataNodes + i] = rf_control;
566 		}
567 	}
568 
569 	/* connect read old parity nodes to xor nodes */
570 	for (i = 0; i < numParityNodes; i++)
571 		for (j = 0; j < numParityNodes; j++) {
572 			readParityNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
573 			xorNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
574 			xorNodes[j].antType[numDataNodes + i] = rf_trueData;
575 		}
576 
577 	/* connect xor nodes to write new parity nodes */
578 	for (i = 0; i < numParityNodes; i++) {
579 		RF_ASSERT(xorNodes[i].numSuccedents == 1);
580 		RF_ASSERT(lpuNodes[i].numAntecedents == 1);
581 		xorNodes[i].succedents[0] = &lpuNodes[i];
582 		lpuNodes[i].antecedents[0] = &xorNodes[i];
583 		lpuNodes[i].antType[0] = rf_trueData;
584 	}
585 
586 	for (i = 0; i < numDataNodes; i++) {
587 		/* connect write new data nodes to unblock node */
588 		RF_ASSERT(writeDataNodes[i].numSuccedents == 1);
589 		RF_ASSERT(unblockNode->numAntecedents == (numDataNodes + (nfaults * numParityNodes)));
590 		writeDataNodes[i].succedents[0] = unblockNode;
591 		unblockNode->antecedents[i] = &writeDataNodes[i];
592 		unblockNode->antType[i] = rf_control;
593 	}
594 
595 	/* connect write new parity nodes to unblock node */
596 	for (i = 0; i < numParityNodes; i++) {
597 		RF_ASSERT(lpuNodes[i].numSuccedents == 1);
598 		lpuNodes[i].succedents[0] = unblockNode;
599 		unblockNode->antecedents[numDataNodes + i] = &lpuNodes[i];
600 		unblockNode->antType[numDataNodes + i] = rf_control;
601 	}
602 
603 	/* connect unblock node to terminator */
604 	RF_ASSERT(unblockNode->numSuccedents == 1);
605 	RF_ASSERT(termNode->numAntecedents == 1);
606 	RF_ASSERT(termNode->numSuccedents == 0);
607 	unblockNode->succedents[0] = termNode;
608 	termNode->antecedents[0] = unblockNode;
609 	termNode->antType[0] = rf_control;
610 }
611 
612 
613 void
614 rf_CreateParityLoggingSmallWriteDAG(
615     RF_Raid_t * raidPtr,
616     RF_AccessStripeMap_t * asmap,
617     RF_DagHeader_t * dag_h,
618     void *bp,
619     RF_RaidAccessFlags_t flags,
620     RF_AllocListElem_t * allocList,
621     const RF_RedFuncs_t * pfuncs,
622     const RF_RedFuncs_t * qfuncs)
623 {
624 	dag_h->creator = "ParityLoggingSmallWriteDAG";
625 	rf_CommonCreateParityLoggingSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_xorFuncs, NULL);
626 }
627 
628 
629 void
630 rf_CreateParityLoggingLargeWriteDAG(
631     RF_Raid_t * raidPtr,
632     RF_AccessStripeMap_t * asmap,
633     RF_DagHeader_t * dag_h,
634     void *bp,
635     RF_RaidAccessFlags_t flags,
636     RF_AllocListElem_t * allocList,
637     int nfaults,
638     int (*redFunc) (RF_DagNode_t *))
639 {
640 	dag_h->creator = "ParityLoggingSmallWriteDAG";
641 	rf_CommonCreateParityLoggingLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularXorFunc);
642 }
643 #endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
644