sys/dev/raidframe/rf_parityloggingdags.c

   1 /*      $NetBSD: rf_parityloggingdags.c,v 1.18 2006/11/16 01:33:23 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 1.18 2006/11/16 01:33:23 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         int     (*qfunc) (RF_DagNode_t * node);
 343         const char   *name, *qname;
 344         RF_StripeNum_t parityStripeID = rf_RaidAddressToParityStripeID(&(raidPtr->Layout), asmap->raidAddress, &which_ru);
 345 #ifdef RAID_DIAGNOSTIC
 346         long    nfaults = qfuncs ? 2 : 1;
 347 #endif /* RAID_DIAGNOSTIC */
 348
 349         if (rf_dagDebug)
 350                 printf("[Creating parity-logging small-write DAG]\n");
 351         RF_ASSERT(numDataNodes > 0);
 352         RF_ASSERT(nfaults == 1);
 353         dag_h->creator = "ParityLoggingSmallWriteDAG";
 354
 355         /* DAG creation occurs in three steps: 1. count the number of nodes in
 356          * the DAG 2. create the nodes 3. initialize the nodes 4. connect the
 357          * nodes */
 358
 359         /* Step 1. compute number of nodes in the graph */
 360
 361         /* number of nodes: a read and write for each data unit a redundancy
 362          * computation node for each parity node a read and Lpu for each
 363          * parity unit a block and unblock node (2) a terminator node if
 364          * atomic RMW an unlock node for each data unit, redundancy unit */
 365         totalNumNodes = (2 * numDataNodes) + numParityNodes + (2 * numParityNodes) + 3;
 366
 367         nNodes = numDataNodes + numParityNodes;
 368
 369         dag_h->numCommitNodes = numDataNodes + numParityNodes;
 370         dag_h->numCommits = 0;
 371         dag_h->numSuccedents = 1;
 372
 373         /* Step 2. create the nodes */
 374         RF_MallocAndAdd(nodes, totalNumNodes * sizeof(RF_DagNode_t),
 375                         (RF_DagNode_t *), allocList);
 376         i = 0;
 377         blockNode = &nodes[i];
 378         i += 1;
 379         unblockNode = &nodes[i];
 380         i += 1;
 381         readDataNodes = &nodes[i];
 382         i += numDataNodes;
 383         readParityNodes = &nodes[i];
 384         i += numParityNodes;
 385         writeDataNodes = &nodes[i];
 386         i += numDataNodes;
 387         lpuNodes = &nodes[i];
 388         i += numParityNodes;
 389         xorNodes = &nodes[i];
 390         i += numParityNodes;
 391         termNode = &nodes[i];
 392         i += 1;
 393
 394         RF_ASSERT(i == totalNumNodes);
 395
 396         /* Step 3. initialize the nodes */
 397         /* initialize block node (Nil) */
 398         rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nNodes, 0, 0, 0, dag_h, "Nil", allocList);
 399
 400         /* initialize unblock node (Nil) */
 401         rf_InitNode(unblockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nNodes, 0, 0, dag_h, "Nil", allocList);
 402
 403         /* initialize terminatory node (Trm) */
 404         rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
 405
 406         /* initialize nodes which read old data (Rod) */
 407         for (i = 0; i < numDataNodes; i++) {
 408                 rf_InitNode(&readDataNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rod", allocList);
 409                 RF_ASSERT(pda != NULL);
 410                 readDataNodes[i].params[0].p = pda;     /* physical disk addr
 411                                                          * desc */
 412                 readDataNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda->numSector << raidPtr->logBytesPerSector);    /* buffer to hold old data */
 413                 readDataNodes[i].params[2].v = parityStripeID;
 414                 readDataNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, which_ru);
 415                 pda = pda->next;
 416                 readDataNodes[i].propList[0] = NULL;
 417                 readDataNodes[i].propList[1] = NULL;
 418         }
 419
 420         /* initialize nodes which read old parity (Rop) */
 421         pda = asmap->parityInfo;
 422         i = 0;
 423         for (i = 0; i < numParityNodes; i++) {
 424                 RF_ASSERT(pda != NULL);
 425                 rf_InitNode(&readParityNodes[i], rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, nNodes, 1, 4, 0, dag_h, "Rop", allocList);
 426                 readParityNodes[i].params[0].p = pda;
 427                 readParityNodes[i].params[1].p = rf_AllocBuffer(raidPtr, dag_h, pda->numSector << raidPtr->logBytesPerSector);  /* buffer to hold old parity */
 428                 readParityNodes[i].params[2].v = parityStripeID;
 429                 readParityNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, which_ru);
 430                 readParityNodes[i].propList[0] = NULL;
 431                 pda = pda->next;
 432         }
 433
 434         /* initialize nodes which write new data (Wnd) */
 435         pda = asmap->physInfo;
 436         for (i = 0; i < numDataNodes; i++) {
 437                 RF_ASSERT(pda != NULL);
 438                 rf_InitNode(&writeDataNodes[i], rf_wait, RF_TRUE, rf_DiskWriteFunc, rf_DiskWriteUndoFunc, rf_GenericWakeupFunc, 1, nNodes, 4, 0, dag_h, "Wnd", allocList);
 439                 writeDataNodes[i].params[0].p = pda;    /* physical disk addr
 440                                                          * desc */
 441                 writeDataNodes[i].params[1].p = pda->bufPtr;    /* buffer holding new
 442                                                                  * data to be written */
 443                 writeDataNodes[i].params[2].v = parityStripeID;
 444                 writeDataNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, which_ru);
 445
 446                 pda = pda->next;
 447         }
 448
 449
 450         /* initialize nodes which compute new parity */
 451         /* we use the simple XOR func in the double-XOR case, and when we're
 452          * accessing only a portion of one stripe unit. the distinction
 453          * between the two is that the regular XOR func assumes that the
 454          * targbuf is a full SU in size, and examines the pda associated with
 455          * the buffer to decide where within the buffer to XOR the data,
 456          * whereas the simple XOR func just XORs the data into the start of
 457          * the buffer. */
 458         if ((numParityNodes == 2) || ((numDataNodes == 1) && (asmap->totalSectorsAccessed < raidPtr->Layout.sectorsPerStripeUnit))) {
 459                 func = pfuncs->simple;
 460                 undoFunc = rf_NullNodeUndoFunc;
 461                 name = pfuncs->SimpleName;
 462                 if (qfuncs) {
 463                         qfunc = qfuncs->simple;
 464                         qname = qfuncs->SimpleName;
 465                 }
 466         } else {
 467                 func = pfuncs->regular;
 468                 undoFunc = rf_NullNodeUndoFunc;
 469                 name = pfuncs->RegularName;
 470                 if (qfuncs) {
 471                         qfunc = qfuncs->regular;
 472                         qname = qfuncs->RegularName;
 473                 }
 474         }
 475         /* initialize the xor nodes: params are {pda,buf} from {Rod,Wnd,Rop}
 476          * nodes, and raidPtr  */
 477         if (numParityNodes == 2) {      /* double-xor case */
 478                 for (i = 0; i < numParityNodes; i++) {
 479                         rf_InitNode(&xorNodes[i], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, 7, 1, dag_h, name, allocList);     /* no wakeup func for
 480                                                                                                                                          * xor */
 481                         xorNodes[i].flags |= RF_DAGNODE_FLAG_YIELD;
 482                         xorNodes[i].params[0] = readDataNodes[i].params[0];
 483                         xorNodes[i].params[1] = readDataNodes[i].params[1];
 484                         xorNodes[i].params[2] = readParityNodes[i].params[0];
 485                         xorNodes[i].params[3] = readParityNodes[i].params[1];
 486                         xorNodes[i].params[4] = writeDataNodes[i].params[0];
 487                         xorNodes[i].params[5] = writeDataNodes[i].params[1];
 488                         xorNodes[i].params[6].p = raidPtr;
 489                         xorNodes[i].results[0] = readParityNodes[i].params[1].p;        /* use old parity buf as
 490                                                                                          * target buf */
 491                 }
 492         } else {
 493                 /* there is only one xor node in this case */
 494                 rf_InitNode(&xorNodes[0], rf_wait, RF_TRUE, func, undoFunc, NULL, 1, nNodes, (2 * (numDataNodes + numDataNodes + 1) + 1), 1, dag_h, name, allocList);
 495                 xorNodes[0].flags |= RF_DAGNODE_FLAG_YIELD;
 496                 for (i = 0; i < numDataNodes + 1; i++) {
 497                         /* set up params related to Rod and Rop nodes */
 498                         xorNodes[0].params[2 * i + 0] = readDataNodes[i].params[0];     /* pda */
 499                         xorNodes[0].params[2 * i + 1] = readDataNodes[i].params[1];     /* buffer pointer */
 500                 }
 501                 for (i = 0; i < numDataNodes; i++) {
 502                         /* set up params related to Wnd and Wnp nodes */
 503                         xorNodes[0].params[2 * (numDataNodes + 1 + i) + 0] = writeDataNodes[i].params[0];       /* pda */
 504                         xorNodes[0].params[2 * (numDataNodes + 1 + i) + 1] = writeDataNodes[i].params[1];       /* buffer pointer */
 505                 }
 506                 xorNodes[0].params[2 * (numDataNodes + numDataNodes + 1)].p = raidPtr;  /* xor node needs to get
 507                                                                                          * at RAID information */
 508                 xorNodes[0].results[0] = readParityNodes[0].params[1].p;
 509         }
 510
 511         /* initialize the log node(s) */
 512         pda = asmap->parityInfo;
 513         for (i = 0; i < numParityNodes; i++) {
 514                 RF_ASSERT(pda);
 515                 rf_InitNode(&lpuNodes[i], rf_wait, RF_FALSE, rf_ParityLogUpdateFunc, rf_ParityLogUpdateUndoFunc, rf_GenericWakeupFunc, 1, 1, 2, 0, dag_h, "Lpu", allocList);
 516                 lpuNodes[i].params[0].p = pda;  /* PhysDiskAddr of parity */
 517                 lpuNodes[i].params[1].p = xorNodes[i].results[0];       /* buffer pointer to
 518                                                                          * parity */
 519                 pda = pda->next;
 520         }
 521
 522
 523         /* Step 4. connect the nodes */
 524
 525         /* connect header to block node */
 526         RF_ASSERT(dag_h->numSuccedents == 1);
 527         RF_ASSERT(blockNode->numAntecedents == 0);
 528         dag_h->succedents[0] = blockNode;
 529
 530         /* connect block node to read old data nodes */
 531         RF_ASSERT(blockNode->numSuccedents == (numDataNodes + numParityNodes));
 532         for (i = 0; i < numDataNodes; i++) {
 533                 blockNode->succedents[i] = &readDataNodes[i];
 534                 RF_ASSERT(readDataNodes[i].numAntecedents == 1);
 535                 readDataNodes[i].antecedents[0] = blockNode;
 536                 readDataNodes[i].antType[0] = rf_control;
 537         }
 538
 539         /* connect block node to read old parity nodes */
 540         for (i = 0; i < numParityNodes; i++) {
 541                 blockNode->succedents[numDataNodes + i] = &readParityNodes[i];
 542                 RF_ASSERT(readParityNodes[i].numAntecedents == 1);
 543                 readParityNodes[i].antecedents[0] = blockNode;
 544                 readParityNodes[i].antType[0] = rf_control;
 545         }
 546
 547         /* connect read old data nodes to write new data nodes */
 548         for (i = 0; i < numDataNodes; i++) {
 549                 RF_ASSERT(readDataNodes[i].numSuccedents == numDataNodes + numParityNodes);
 550                 for (j = 0; j < numDataNodes; j++) {
 551                         RF_ASSERT(writeDataNodes[j].numAntecedents == numDataNodes + numParityNodes);
 552                         readDataNodes[i].succedents[j] = &writeDataNodes[j];
 553                         writeDataNodes[j].antecedents[i] = &readDataNodes[i];
 554                         if (i == j)
 555                                 writeDataNodes[j].antType[i] = rf_antiData;
 556                         else
 557                                 writeDataNodes[j].antType[i] = rf_control;
 558                 }
 559         }
 560
 561         /* connect read old data nodes to xor nodes */
 562         for (i = 0; i < numDataNodes; i++)
 563                 for (j = 0; j < numParityNodes; j++) {
 564                         RF_ASSERT(xorNodes[j].numAntecedents == numDataNodes + numParityNodes);
 565                         readDataNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
 566                         xorNodes[j].antecedents[i] = &readDataNodes[i];
 567                         xorNodes[j].antType[i] = rf_trueData;
 568                 }
 569
 570         /* connect read old parity nodes to write new data nodes */
 571         for (i = 0; i < numParityNodes; i++) {
 572                 RF_ASSERT(readParityNodes[i].numSuccedents == numDataNodes + numParityNodes);
 573                 for (j = 0; j < numDataNodes; j++) {
 574                         readParityNodes[i].succedents[j] = &writeDataNodes[j];
 575                         writeDataNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
 576                         writeDataNodes[j].antType[numDataNodes + i] = rf_control;
 577                 }
 578         }
 579
 580         /* connect read old parity nodes to xor nodes */
 581         for (i = 0; i < numParityNodes; i++)
 582                 for (j = 0; j < numParityNodes; j++) {
 583                         readParityNodes[i].succedents[numDataNodes + j] = &xorNodes[j];
 584                         xorNodes[j].antecedents[numDataNodes + i] = &readParityNodes[i];
 585                         xorNodes[j].antType[numDataNodes + i] = rf_trueData;
 586                 }
 587
 588         /* connect xor nodes to write new parity nodes */
 589         for (i = 0; i < numParityNodes; i++) {
 590                 RF_ASSERT(xorNodes[i].numSuccedents == 1);
 591                 RF_ASSERT(lpuNodes[i].numAntecedents == 1);
 592                 xorNodes[i].succedents[0] = &lpuNodes[i];
 593                 lpuNodes[i].antecedents[0] = &xorNodes[i];
 594                 lpuNodes[i].antType[0] = rf_trueData;
 595         }
 596
 597         for (i = 0; i < numDataNodes; i++) {
 598                 /* connect write new data nodes to unblock node */
 599                 RF_ASSERT(writeDataNodes[i].numSuccedents == 1);
 600                 RF_ASSERT(unblockNode->numAntecedents == (numDataNodes + (nfaults * numParityNodes)));
 601                 writeDataNodes[i].succedents[0] = unblockNode;
 602                 unblockNode->antecedents[i] = &writeDataNodes[i];
 603                 unblockNode->antType[i] = rf_control;
 604         }
 605
 606         /* connect write new parity nodes to unblock node */
 607         for (i = 0; i < numParityNodes; i++) {
 608                 RF_ASSERT(lpuNodes[i].numSuccedents == 1);
 609                 lpuNodes[i].succedents[0] = unblockNode;
 610                 unblockNode->antecedents[numDataNodes + i] = &lpuNodes[i];
 611                 unblockNode->antType[numDataNodes + i] = rf_control;
 612         }
 613
 614         /* connect unblock node to terminator */
 615         RF_ASSERT(unblockNode->numSuccedents == 1);
 616         RF_ASSERT(termNode->numAntecedents == 1);
 617         RF_ASSERT(termNode->numSuccedents == 0);
 618         unblockNode->succedents[0] = termNode;
 619         termNode->antecedents[0] = unblockNode;
 620         termNode->antType[0] = rf_control;
 621 }
 622
 623
 624 void
 625 rf_CreateParityLoggingSmallWriteDAG(
 626     RF_Raid_t * raidPtr,
 627     RF_AccessStripeMap_t * asmap,
 628     RF_DagHeader_t * dag_h,
 629     void *bp,
 630     RF_RaidAccessFlags_t flags,
 631     RF_AllocListElem_t * allocList,
 632     const RF_RedFuncs_t * pfuncs,
 633     const RF_RedFuncs_t * qfuncs)
 634 {
 635         dag_h->creator = "ParityLoggingSmallWriteDAG";
 636         rf_CommonCreateParityLoggingSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_xorFuncs, NULL);
 637 }
 638
 639
 640 void
 641 rf_CreateParityLoggingLargeWriteDAG(
 642     RF_Raid_t * raidPtr,
 643     RF_AccessStripeMap_t * asmap,
 644     RF_DagHeader_t * dag_h,
 645     void *bp,
 646     RF_RaidAccessFlags_t flags,
 647     RF_AllocListElem_t * allocList,
 648     int nfaults,
 649     int (*redFunc) (RF_DagNode_t *))
 650 {
 651         dag_h->creator = "ParityLoggingSmallWriteDAG";
 652         rf_CommonCreateParityLoggingLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularXorFunc);
 653 }
 654 #endif                          /* RF_INCLUDE_PARITYLOGGING > 0 */