After much delay and anticipation, welcome RAIDFrame into the FreeBSD

world.  This should be considered highly experimental.

Approved-by:	re

1 files changed, 1074 insertions, 0 deletions

diff --git a/sys/dev/raidframe/rf_paritylogging.c b/sys/dev/raidframe/rf_paritylogging.c
new file mode 100644
index 0000000..f318655
--- /dev/null
+++ b/sys/dev/raidframe/rf_paritylogging.c
@@ -0,0 +1,1074 @@
+/*	$FreeBSD$ */
+/*	$NetBSD: rf_paritylogging.c,v 1.10 2000/02/12 16:06:27 oster Exp $	*/
+/*
+ * Copyright (c) 1995 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Author: William V. Courtright II
+ *
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+
+/*
+  parity logging configuration, dag selection, and mapping is implemented here
+ */
+
+#include <dev/raidframe/rf_archs.h>
+
+#if RF_INCLUDE_PARITYLOGGING > 0
+
+#include <dev/raidframe/rf_types.h>
+#include <dev/raidframe/rf_raid.h>
+#include <dev/raidframe/rf_dag.h>
+#include <dev/raidframe/rf_dagutils.h>
+#include <dev/raidframe/rf_dagfuncs.h>
+#include <dev/raidframe/rf_dagffrd.h>
+#include <dev/raidframe/rf_dagffwr.h>
+#include <dev/raidframe/rf_dagdegrd.h>
+#include <dev/raidframe/rf_dagdegwr.h>
+#include <dev/raidframe/rf_paritylog.h>
+#include <dev/raidframe/rf_paritylogDiskMgr.h>
+#include <dev/raidframe/rf_paritylogging.h>
+#include <dev/raidframe/rf_parityloggingdags.h>
+#include <dev/raidframe/rf_general.h>
+#include <dev/raidframe/rf_map.h>
+#include <dev/raidframe/rf_utils.h>
+#include <dev/raidframe/rf_shutdown.h>
+#include <dev/raidframe/rf_kintf.h>
+
+typedef struct RF_ParityLoggingConfigInfo_s {
+	RF_RowCol_t **stripeIdentifier;	/* filled in at config time & used by
+					 * IdentifyStripe */
+}       RF_ParityLoggingConfigInfo_t;
+
+static void FreeRegionInfo(RF_Raid_t * raidPtr, RF_RegionId_t regionID);
+static void rf_ShutdownParityLogging(RF_ThreadArg_t arg);
+static void rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg);
+static void rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg);
+static void rf_ShutdownParityLoggingRegionBufferPool(RF_ThreadArg_t arg);
+static void rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg);
+static void rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg);
+
+int 
+rf_ConfigureParityLogging(
+    RF_ShutdownList_t ** listp,
+    RF_Raid_t * raidPtr,
+    RF_Config_t * cfgPtr)
+{
+	int     i, j, startdisk, rc;
+	RF_SectorCount_t totalLogCapacity, fragmentation, lastRegionCapacity;
+	RF_SectorCount_t parityBufferCapacity, maxRegionParityRange;
+	RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
+	RF_ParityLoggingConfigInfo_t *info;
+	RF_ParityLog_t *l = NULL, *next;
+	caddr_t lHeapPtr;
+
+	if (rf_numParityRegions <= 0)
+		return(EINVAL);
+
+	/*
+         * We create multiple entries on the shutdown list here, since
+         * this configuration routine is fairly complicated in and of
+         * itself, and this makes backing out of a failed configuration
+         * much simpler.
+         */
+
+	raidPtr->numSectorsPerLog = RF_DEFAULT_NUM_SECTORS_PER_LOG;
+
+	/* create a parity logging configuration structure */
+	RF_MallocAndAdd(info, sizeof(RF_ParityLoggingConfigInfo_t), 
+			(RF_ParityLoggingConfigInfo_t *), 
+			raidPtr->cleanupList);
+	if (info == NULL)
+		return (ENOMEM);
+	layoutPtr->layoutSpecificInfo = (void *) info;
+
+	RF_ASSERT(raidPtr->numRow == 1);
+
+	/* the stripe identifier must identify the disks in each stripe, IN
+	 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
+	info->stripeIdentifier = rf_make_2d_array((raidPtr->numCol), 
+						  (raidPtr->numCol), 
+						  raidPtr->cleanupList);
+	if (info->stripeIdentifier == NULL)
+		return (ENOMEM);
+
+	startdisk = 0;
+	for (i = 0; i < (raidPtr->numCol); i++) {
+		for (j = 0; j < (raidPtr->numCol); j++) {
+			info->stripeIdentifier[i][j] = (startdisk + j) % 
+				(raidPtr->numCol - 1);
+		}
+		if ((--startdisk) < 0)
+			startdisk = raidPtr->numCol - 1 - 1;
+	}
+
+	/* fill in the remaining layout parameters */
+	layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
+	layoutPtr->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit << 
+		raidPtr->logBytesPerSector;
+	layoutPtr->numParityCol = 1;
+	layoutPtr->numParityLogCol = 1;
+	layoutPtr->numDataCol = raidPtr->numCol - layoutPtr->numParityCol - 
+		layoutPtr->numParityLogCol;
+	layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * 
+		layoutPtr->sectorsPerStripeUnit;
+	layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;
+	raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk * 
+		layoutPtr->sectorsPerStripeUnit;
+
+	raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * 
+		layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
+
+	/* configure parity log parameters
+	 * 
+	 * parameter               comment/constraints 
+	 * ------------------------------------------- 
+	 * numParityRegions*       all regions (except possibly last) 
+	 *                         of equal size 
+	 * totalInCoreLogCapacity* amount of memory in bytes available 
+	 *                         for in-core logs (default 1 MB) 
+	 * numSectorsPerLog#       capacity of an in-core log in sectors 
+	 *                         (1 * disk track)
+	 * numParityLogs           total number of in-core logs,
+	 *                         should be at least numParityRegions 
+	 * regionLogCapacity       size of a region log (except possibly 
+	 *                         last one) in sectors 
+	 * totalLogCapacity        total amount of log space in sectors
+	 * 
+	 * where '*' denotes a user settable parameter. 
+	 * Note that logs are fixed to be the size of a disk track, 
+	 * value #defined in rf_paritylog.h
+	 * 
+	 */
+
+	totalLogCapacity = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit * layoutPtr->numParityLogCol;
+	raidPtr->regionLogCapacity = totalLogCapacity / rf_numParityRegions;
+	if (rf_parityLogDebug)
+		printf("bytes per sector %d\n", raidPtr->bytesPerSector);
+
+	/* reduce fragmentation within a disk region by adjusting the number
+	 * of regions in an attempt to allow an integral number of logs to fit
+	 * into a disk region */
+	fragmentation = raidPtr->regionLogCapacity % raidPtr->numSectorsPerLog;
+	if (fragmentation > 0)
+		for (i = 1; i < (raidPtr->numSectorsPerLog / 2); i++) {
+			if (((totalLogCapacity / (rf_numParityRegions + i)) % 
+			     raidPtr->numSectorsPerLog) < fragmentation) {
+				rf_numParityRegions++;
+				raidPtr->regionLogCapacity = totalLogCapacity /
+					rf_numParityRegions;
+				fragmentation = raidPtr->regionLogCapacity % 
+					raidPtr->numSectorsPerLog;
+			}
+			if (((totalLogCapacity / (rf_numParityRegions - i)) % 
+			     raidPtr->numSectorsPerLog) < fragmentation) {
+				rf_numParityRegions--;
+				raidPtr->regionLogCapacity = totalLogCapacity /
+					rf_numParityRegions;
+				fragmentation = raidPtr->regionLogCapacity % 
+					raidPtr->numSectorsPerLog;
+			}
+		}
+	/* ensure integral number of regions per log */
+	raidPtr->regionLogCapacity = (raidPtr->regionLogCapacity / 
+				      raidPtr->numSectorsPerLog) * 
+		raidPtr->numSectorsPerLog;
+
+	raidPtr->numParityLogs = rf_totalInCoreLogCapacity / 
+		(raidPtr->bytesPerSector * raidPtr->numSectorsPerLog);
+	/* to avoid deadlock, must ensure that enough logs exist for each
+	 * region to have one simultaneously */
+	if (raidPtr->numParityLogs < rf_numParityRegions)
+		raidPtr->numParityLogs = rf_numParityRegions;
+
+	/* create region information structs */
+	printf("Allocating %d bytes for in-core parity region info\n",
+	       (int) (rf_numParityRegions * sizeof(RF_RegionInfo_t)));
+	RF_Malloc(raidPtr->regionInfo, 
+		  (rf_numParityRegions * sizeof(RF_RegionInfo_t)), 
+		  (RF_RegionInfo_t *));
+	if (raidPtr->regionInfo == NULL)
+		return (ENOMEM);
+
+	/* last region may not be full capacity */
+	lastRegionCapacity = raidPtr->regionLogCapacity;
+	while ((rf_numParityRegions - 1) * raidPtr->regionLogCapacity + 
+	       lastRegionCapacity > totalLogCapacity)
+		lastRegionCapacity = lastRegionCapacity - 
+			raidPtr->numSectorsPerLog;
+
+	raidPtr->regionParityRange = raidPtr->sectorsPerDisk / 
+		rf_numParityRegions;
+	maxRegionParityRange = raidPtr->regionParityRange;
+
+/* i can't remember why this line is in the code -wvcii 6/30/95 */
+/*  if (raidPtr->sectorsPerDisk % rf_numParityRegions > 0)
+    regionParityRange++; */
+
+	/* build pool of unused parity logs */
+	printf("Allocating %d bytes for %d parity logs\n",
+	       raidPtr->numParityLogs * raidPtr->numSectorsPerLog * 
+	       raidPtr->bytesPerSector,
+	       raidPtr->numParityLogs);
+	RF_Malloc(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs * 
+		  raidPtr->numSectorsPerLog * raidPtr->bytesPerSector, 
+		  (caddr_t));
+	if (raidPtr->parityLogBufferHeap == NULL)
+		return (ENOMEM);
+	lHeapPtr = raidPtr->parityLogBufferHeap;
+	rc = rf_mutex_init(&raidPtr->parityLogPool.mutex, "RF_PARITYLOGGING1");
+	if (rc) {
+		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", 
+			     __FILE__, __LINE__, rc);
+		RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs * 
+			raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
+		return (ENOMEM);
+	}
+	for (i = 0; i < raidPtr->numParityLogs; i++) {
+		if (i == 0) {
+			RF_Calloc(raidPtr->parityLogPool.parityLogs, 1, 
+				  sizeof(RF_ParityLog_t), (RF_ParityLog_t *));
+			if (raidPtr->parityLogPool.parityLogs == NULL) {
+				RF_Free(raidPtr->parityLogBufferHeap, 
+					raidPtr->numParityLogs * 
+					raidPtr->numSectorsPerLog * 
+					raidPtr->bytesPerSector);
+				return (ENOMEM);
+			}
+			l = raidPtr->parityLogPool.parityLogs;
+		} else {
+			RF_Calloc(l->next, 1, sizeof(RF_ParityLog_t), 
+				  (RF_ParityLog_t *));
+			if (l->next == NULL) {
+				RF_Free(raidPtr->parityLogBufferHeap, 
+					raidPtr->numParityLogs * 
+					raidPtr->numSectorsPerLog * 
+					raidPtr->bytesPerSector);
+				for (l = raidPtr->parityLogPool.parityLogs; 
+				     l;
+				     l = next) {
+					next = l->next;
+					if (l->records)
+						RF_Free(l->records, (raidPtr->numSectorsPerLog * sizeof(RF_ParityLogRecord_t)));
+					RF_Free(l, sizeof(RF_ParityLog_t));
+				}
+				return (ENOMEM);
+			}
+			l = l->next;
+		}
+		l->bufPtr = lHeapPtr;
+		lHeapPtr += raidPtr->numSectorsPerLog * 
+			raidPtr->bytesPerSector;
+		RF_Malloc(l->records, (raidPtr->numSectorsPerLog * 
+				       sizeof(RF_ParityLogRecord_t)), 
+			  (RF_ParityLogRecord_t *));
+		if (l->records == NULL) {
+			RF_Free(raidPtr->parityLogBufferHeap, 
+				raidPtr->numParityLogs * 
+				raidPtr->numSectorsPerLog * 
+				raidPtr->bytesPerSector);
+			for (l = raidPtr->parityLogPool.parityLogs; 
+			     l; 
+			     l = next) {
+				next = l->next;
+				if (l->records)
+					RF_Free(l->records, 
+						(raidPtr->numSectorsPerLog * 
+						 sizeof(RF_ParityLogRecord_t)));
+				RF_Free(l, sizeof(RF_ParityLog_t));
+			}
+			return (ENOMEM);
+		}
+	}
+	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLoggingPool, raidPtr);
+	if (rc) {
+		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
+		    __LINE__, rc);
+		rf_ShutdownParityLoggingPool(raidPtr);
+		return (rc);
+	}
+	/* build pool of region buffers */
+	rc = rf_mutex_init(&raidPtr->regionBufferPool.mutex, "RF_PARITYLOGGING3");
+	if (rc) {
+		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", 
+			     __FILE__, __LINE__, rc);
+		return (ENOMEM);
+	}
+	rc = rf_cond_init(&raidPtr->regionBufferPool.cond);
+	if (rc) {
+		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n", 
+			     __FILE__, __LINE__, rc);
+		rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
+		return (ENOMEM);
+	}
+	raidPtr->regionBufferPool.bufferSize = raidPtr->regionLogCapacity * 
+		raidPtr->bytesPerSector;
+	printf("regionBufferPool.bufferSize %d\n", 
+	       raidPtr->regionBufferPool.bufferSize);
+
+	/* for now, only one region at a time may be reintegrated */
+	raidPtr->regionBufferPool.totalBuffers = 1;	
+
+	raidPtr->regionBufferPool.availableBuffers = 
+		raidPtr->regionBufferPool.totalBuffers;
+	raidPtr->regionBufferPool.availBuffersIndex = 0;
+	raidPtr->regionBufferPool.emptyBuffersIndex = 0;
+	printf("Allocating %d bytes for regionBufferPool\n",
+	       (int) (raidPtr->regionBufferPool.totalBuffers * 
+		      sizeof(caddr_t)));
+	RF_Malloc(raidPtr->regionBufferPool.buffers, 
+		  raidPtr->regionBufferPool.totalBuffers * sizeof(caddr_t), 
+		  (caddr_t *));
+	if (raidPtr->regionBufferPool.buffers == NULL) {
+		rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
+		rf_cond_destroy(&raidPtr->regionBufferPool.cond);
+		return (ENOMEM);
+	}
+	for (i = 0; i < raidPtr->regionBufferPool.totalBuffers; i++) {
+		printf("Allocating %d bytes for regionBufferPool#%d\n",
+		       (int) (raidPtr->regionBufferPool.bufferSize * 
+			      sizeof(char)), i);
+		RF_Malloc(raidPtr->regionBufferPool.buffers[i], 
+			  raidPtr->regionBufferPool.bufferSize * sizeof(char),
+			  (caddr_t));
+		if (raidPtr->regionBufferPool.buffers[i] == NULL) {
+			rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
+			rf_cond_destroy(&raidPtr->regionBufferPool.cond);
+			for (j = 0; j < i; j++) {
+				RF_Free(raidPtr->regionBufferPool.buffers[i], 
+					raidPtr->regionBufferPool.bufferSize *
+					sizeof(char));
+			}
+			RF_Free(raidPtr->regionBufferPool.buffers, 
+				raidPtr->regionBufferPool.totalBuffers * 
+				sizeof(caddr_t));
+			return (ENOMEM);
+		}
+		printf("raidPtr->regionBufferPool.buffers[%d] = %lx\n", i,
+		    (long) raidPtr->regionBufferPool.buffers[i]);
+	}
+	rc = rf_ShutdownCreate(listp, 
+			       rf_ShutdownParityLoggingRegionBufferPool,
+			       raidPtr);
+	if (rc) {
+		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
+		    __LINE__, rc);
+		rf_ShutdownParityLoggingRegionBufferPool(raidPtr);
+		return (rc);
+	}
+	/* build pool of parity buffers */
+	parityBufferCapacity = maxRegionParityRange;
+	rc = rf_mutex_init(&raidPtr->parityBufferPool.mutex, "RF_PARITYLOGGING3");
+	if (rc) {
+		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", 
+			     __FILE__, __LINE__, rc);
+		return (rc);
+	}
+	rc = rf_cond_init(&raidPtr->parityBufferPool.cond);
+	if (rc) {
+		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n", 
+			     __FILE__, __LINE__, rc);
+		rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
+		return (ENOMEM);
+	}
+	raidPtr->parityBufferPool.bufferSize = parityBufferCapacity * 
+		raidPtr->bytesPerSector;
+	printf("parityBufferPool.bufferSize %d\n", 
+	       raidPtr->parityBufferPool.bufferSize);
+
+	/* for now, only one region at a time may be reintegrated */
+	raidPtr->parityBufferPool.totalBuffers = 1;	
+
+	raidPtr->parityBufferPool.availableBuffers = 
+		raidPtr->parityBufferPool.totalBuffers;
+	raidPtr->parityBufferPool.availBuffersIndex = 0;
+	raidPtr->parityBufferPool.emptyBuffersIndex = 0;
+	printf("Allocating %d bytes for parityBufferPool of %d units\n",
+	       (int) (raidPtr->parityBufferPool.totalBuffers * 
+		      sizeof(caddr_t)),
+	       raidPtr->parityBufferPool.totalBuffers );
+	RF_Malloc(raidPtr->parityBufferPool.buffers, 
+		  raidPtr->parityBufferPool.totalBuffers * sizeof(caddr_t), 
+		  (caddr_t *));
+	if (raidPtr->parityBufferPool.buffers == NULL) {
+		rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
+		rf_cond_destroy(&raidPtr->parityBufferPool.cond);
+		return (ENOMEM);
+	}
+	for (i = 0; i < raidPtr->parityBufferPool.totalBuffers; i++) {
+		printf("Allocating %d bytes for parityBufferPool#%d\n",
+		       (int) (raidPtr->parityBufferPool.bufferSize * 
+			      sizeof(char)),i);
+		RF_Malloc(raidPtr->parityBufferPool.buffers[i], 
+			  raidPtr->parityBufferPool.bufferSize * sizeof(char),
+			  (caddr_t));
+		if (raidPtr->parityBufferPool.buffers == NULL) {
+			rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
+			rf_cond_destroy(&raidPtr->parityBufferPool.cond);
+			for (j = 0; j < i; j++) {
+				RF_Free(raidPtr->parityBufferPool.buffers[i], 
+					raidPtr->regionBufferPool.bufferSize * 
+					sizeof(char));
+			}
+			RF_Free(raidPtr->parityBufferPool.buffers, 
+				raidPtr->regionBufferPool.totalBuffers * 
+				sizeof(caddr_t));
+			return (ENOMEM);
+		}
+		printf("parityBufferPool.buffers[%d] = %lx\n", i,
+		    (long) raidPtr->parityBufferPool.buffers[i]);
+	}
+	rc = rf_ShutdownCreate(listp, 
+			       rf_ShutdownParityLoggingParityBufferPool, 
+			       raidPtr);
+	if (rc) {
+		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
+		    __LINE__, rc);
+		rf_ShutdownParityLoggingParityBufferPool(raidPtr);
+		return (rc);
+	}
+	/* initialize parityLogDiskQueue */
+	rc = rf_create_managed_mutex(listp, 
+				     &raidPtr->parityLogDiskQueue.mutex);
+	if (rc) {
+		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", 
+			     __FILE__, __LINE__, rc);
+		return (rc);
+	}
+	rc = rf_create_managed_cond(listp, &raidPtr->parityLogDiskQueue.cond);
+	if (rc) {
+		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n", 
+			     __FILE__, __LINE__, rc);
+		return (rc);
+	}
+	raidPtr->parityLogDiskQueue.flushQueue = NULL;
+	raidPtr->parityLogDiskQueue.reintQueue = NULL;
+	raidPtr->parityLogDiskQueue.bufHead = NULL;
+	raidPtr->parityLogDiskQueue.bufTail = NULL;
+	raidPtr->parityLogDiskQueue.reintHead = NULL;
+	raidPtr->parityLogDiskQueue.reintTail = NULL;
+	raidPtr->parityLogDiskQueue.logBlockHead = NULL;
+	raidPtr->parityLogDiskQueue.logBlockTail = NULL;
+	raidPtr->parityLogDiskQueue.reintBlockHead = NULL;
+	raidPtr->parityLogDiskQueue.reintBlockTail = NULL;
+	raidPtr->parityLogDiskQueue.freeDataList = NULL;
+	raidPtr->parityLogDiskQueue.freeCommonList = NULL;
+
+	rc = rf_ShutdownCreate(listp, 
+			       rf_ShutdownParityLoggingDiskQueue, 
+			       raidPtr);
+	if (rc) {
+		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
+		    __LINE__, rc);
+		return (rc);
+	}
+	for (i = 0; i < rf_numParityRegions; i++) {
+		rc = rf_mutex_init(&raidPtr->regionInfo[i].mutex, "RF_PARITYLOGGING3");
+		if (rc) {
+			RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", __FILE__,
+			    __LINE__, rc);
+			for (j = 0; j < i; j++)
+				FreeRegionInfo(raidPtr, j);
+			RF_Free(raidPtr->regionInfo, 
+				(rf_numParityRegions * 
+				 sizeof(RF_RegionInfo_t)));
+			return (ENOMEM);
+		}
+		rc = rf_mutex_init(&raidPtr->regionInfo[i].reintMutex, "RF_PARITYLOGGING4");
+		if (rc) {
+			RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", __FILE__,
+			    __LINE__, rc);
+			rf_mutex_destroy(&raidPtr->regionInfo[i].mutex);
+			for (j = 0; j < i; j++)
+				FreeRegionInfo(raidPtr, j);
+			RF_Free(raidPtr->regionInfo, 
+				(rf_numParityRegions * 
+				 sizeof(RF_RegionInfo_t)));
+			return (ENOMEM);
+		}
+		raidPtr->regionInfo[i].reintInProgress = RF_FALSE;
+		raidPtr->regionInfo[i].regionStartAddr = 
+			raidPtr->regionLogCapacity * i;
+		raidPtr->regionInfo[i].parityStartAddr = 
+			raidPtr->regionParityRange * i;
+		if (i < rf_numParityRegions - 1) {
+			raidPtr->regionInfo[i].capacity = 
+				raidPtr->regionLogCapacity;
+			raidPtr->regionInfo[i].numSectorsParity = 
+				raidPtr->regionParityRange;
+		} else {
+			raidPtr->regionInfo[i].capacity = 
+				lastRegionCapacity;
+			raidPtr->regionInfo[i].numSectorsParity = 
+				raidPtr->sectorsPerDisk - 
+				raidPtr->regionParityRange * i;
+			if (raidPtr->regionInfo[i].numSectorsParity > 
+			    maxRegionParityRange)
+				maxRegionParityRange = 
+					raidPtr->regionInfo[i].numSectorsParity;
+		}
+		raidPtr->regionInfo[i].diskCount = 0;
+		RF_ASSERT(raidPtr->regionInfo[i].capacity + 
+			  raidPtr->regionInfo[i].regionStartAddr <= 
+			  totalLogCapacity);
+		RF_ASSERT(raidPtr->regionInfo[i].parityStartAddr + 
+			  raidPtr->regionInfo[i].numSectorsParity <= 
+			  raidPtr->sectorsPerDisk);
+		printf("Allocating %d bytes for region %d\n",
+		       (int) (raidPtr->regionInfo[i].capacity *
+			   sizeof(RF_DiskMap_t)), i);
+		RF_Malloc(raidPtr->regionInfo[i].diskMap, 
+			  (raidPtr->regionInfo[i].capacity *
+			   sizeof(RF_DiskMap_t)), 
+			  (RF_DiskMap_t *));
+		if (raidPtr->regionInfo[i].diskMap == NULL) {
+			rf_mutex_destroy(&raidPtr->regionInfo[i].mutex);
+			rf_mutex_destroy(&raidPtr->regionInfo[i].reintMutex);
+			for (j = 0; j < i; j++)
+				FreeRegionInfo(raidPtr, j);
+			RF_Free(raidPtr->regionInfo, 
+				(rf_numParityRegions * 
+				 sizeof(RF_RegionInfo_t)));
+			return (ENOMEM);
+		}
+		raidPtr->regionInfo[i].loggingEnabled = RF_FALSE;
+		raidPtr->regionInfo[i].coreLog = NULL;
+	}
+	rc = rf_ShutdownCreate(listp,
+			       rf_ShutdownParityLoggingRegionInfo, 
+			       raidPtr);
+	if (rc) {
+		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
+		    __LINE__, rc);
+		rf_ShutdownParityLoggingRegionInfo(raidPtr);
+		return (rc);
+	}
+	RF_ASSERT(raidPtr->parityLogDiskQueue.threadState == 0);
+	raidPtr->parityLogDiskQueue.threadState = RF_PLOG_CREATED;
+	rc = RF_CREATE_THREAD(raidPtr->pLogDiskThreadHandle, 
+			      rf_ParityLoggingDiskManager, raidPtr,"rf_log");
+	if (rc) {
+		raidPtr->parityLogDiskQueue.threadState = 0;
+		RF_ERRORMSG3("Unable to create parity logging disk thread file %s line %d rc=%d\n",
+		    __FILE__, __LINE__, rc);
+		return (ENOMEM);
+	}
+	/* wait for thread to start */
+	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
+	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_RUNNING)) {
+		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond, 
+			     raidPtr->parityLogDiskQueue.mutex);
+	}
+	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
+
+	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLogging, raidPtr);
+	if (rc) {
+		RF_ERRORMSG1("Got rc=%d adding parity logging shutdown event\n", rc);
+		rf_ShutdownParityLogging(raidPtr);
+		return (rc);
+	}
+	if (rf_parityLogDebug) {
+		printf("                            size of disk log in sectors: %d\n",
+		    (int) totalLogCapacity);
+		printf("                            total number of parity regions is %d\n", (int) rf_numParityRegions);
+		printf("                            nominal sectors of log per parity region is %d\n", (int) raidPtr->regionLogCapacity);
+		printf("                            nominal region fragmentation is %d sectors\n", (int) fragmentation);
+		printf("                            total number of parity logs is %d\n", raidPtr->numParityLogs);
+		printf("                            parity log size is %d sectors\n", raidPtr->numSectorsPerLog);
+		printf("                            total in-core log space is %d bytes\n", (int) rf_totalInCoreLogCapacity);
+	}
+	rf_EnableParityLogging(raidPtr);
+
+	return (0);
+}
+
+static void 
+FreeRegionInfo(
+    RF_Raid_t * raidPtr,
+    RF_RegionId_t regionID)
+{
+	RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
+	RF_Free(raidPtr->regionInfo[regionID].diskMap, 
+		(raidPtr->regionInfo[regionID].capacity * 
+		 sizeof(RF_DiskMap_t)));
+	if (!rf_forceParityLogReint && raidPtr->regionInfo[regionID].coreLog) {
+		rf_ReleaseParityLogs(raidPtr, 
+				     raidPtr->regionInfo[regionID].coreLog);
+		raidPtr->regionInfo[regionID].coreLog = NULL;
+	} else {
+		RF_ASSERT(raidPtr->regionInfo[regionID].coreLog == NULL);
+		RF_ASSERT(raidPtr->regionInfo[regionID].diskCount == 0);
+	}
+	RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
+	rf_mutex_destroy(&raidPtr->regionInfo[regionID].mutex);
+	rf_mutex_destroy(&raidPtr->regionInfo[regionID].reintMutex);
+}
+
+
+static void 
+FreeParityLogQueue(
+    RF_Raid_t * raidPtr,
+    RF_ParityLogQueue_t * queue)
+{
+	RF_ParityLog_t *l1, *l2;
+
+	RF_LOCK_MUTEX(queue->mutex);
+	l1 = queue->parityLogs;
+	while (l1) {
+		l2 = l1;
+		l1 = l2->next;
+		RF_Free(l2->records, (raidPtr->numSectorsPerLog * 
+				      sizeof(RF_ParityLogRecord_t)));
+		RF_Free(l2, sizeof(RF_ParityLog_t));
+	}
+	RF_UNLOCK_MUTEX(queue->mutex);
+	rf_mutex_destroy(&queue->mutex);
+}
+
+
+static void 
+FreeRegionBufferQueue(RF_RegionBufferQueue_t * queue)
+{
+	int     i;
+
+	RF_LOCK_MUTEX(queue->mutex);
+	if (queue->availableBuffers != queue->totalBuffers) {
+		printf("Attempt to free region queue which is still in use!\n");
+		RF_ASSERT(0);
+	}
+	for (i = 0; i < queue->totalBuffers; i++)
+		RF_Free(queue->buffers[i], queue->bufferSize);
+	RF_Free(queue->buffers, queue->totalBuffers * sizeof(caddr_t));
+	RF_UNLOCK_MUTEX(queue->mutex);
+	rf_mutex_destroy(&queue->mutex);
+}
+
+static void 
+rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg)
+{
+	RF_Raid_t *raidPtr;
+	RF_RegionId_t i;
+
+	raidPtr = (RF_Raid_t *) arg;
+	if (rf_parityLogDebug) {
+		printf("raid%d: ShutdownParityLoggingRegionInfo\n", 
+		       raidPtr->raidid);
+	}
+	/* free region information structs */
+	for (i = 0; i < rf_numParityRegions; i++)
+		FreeRegionInfo(raidPtr, i);
+	RF_Free(raidPtr->regionInfo, (rf_numParityRegions * 
+				      sizeof(raidPtr->regionInfo)));
+	raidPtr->regionInfo = NULL;
+}
+
+static void 
+rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg)
+{
+	RF_Raid_t *raidPtr;
+
+	raidPtr = (RF_Raid_t *) arg;
+	if (rf_parityLogDebug) {
+		printf("raid%d: ShutdownParityLoggingPool\n", raidPtr->raidid);
+	}
+	/* free contents of parityLogPool */
+	FreeParityLogQueue(raidPtr, &raidPtr->parityLogPool);
+	RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs * 
+		raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
+}
+
+static void 
+rf_ShutdownParityLoggingRegionBufferPool(RF_ThreadArg_t arg)
+{
+	RF_Raid_t *raidPtr;
+
+	raidPtr = (RF_Raid_t *) arg;
+	if (rf_parityLogDebug) {
+		printf("raid%d: ShutdownParityLoggingRegionBufferPool\n", 
+		       raidPtr->raidid);
+	}
+	FreeRegionBufferQueue(&raidPtr->regionBufferPool);
+}
+
+static void 
+rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg)
+{
+	RF_Raid_t *raidPtr;
+
+	raidPtr = (RF_Raid_t *) arg;
+	if (rf_parityLogDebug) {
+		printf("raid%d: ShutdownParityLoggingParityBufferPool\n",
+		       raidPtr->raidid);
+	}
+	FreeRegionBufferQueue(&raidPtr->parityBufferPool);
+}
+
+static void 
+rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg)
+{
+	RF_ParityLogData_t *d;
+	RF_CommonLogData_t *c;
+	RF_Raid_t *raidPtr;
+
+	raidPtr = (RF_Raid_t *) arg;
+	if (rf_parityLogDebug) {
+		printf("raid%d: ShutdownParityLoggingDiskQueue\n",
+		       raidPtr->raidid);
+	}
+	/* free disk manager stuff */
+	RF_ASSERT(raidPtr->parityLogDiskQueue.bufHead == NULL);
+	RF_ASSERT(raidPtr->parityLogDiskQueue.bufTail == NULL);
+	RF_ASSERT(raidPtr->parityLogDiskQueue.reintHead == NULL);
+	RF_ASSERT(raidPtr->parityLogDiskQueue.reintTail == NULL);
+	while (raidPtr->parityLogDiskQueue.freeDataList) {
+		d = raidPtr->parityLogDiskQueue.freeDataList;
+		raidPtr->parityLogDiskQueue.freeDataList = 
+			raidPtr->parityLogDiskQueue.freeDataList->next;
+		RF_Free(d, sizeof(RF_ParityLogData_t));
+	}
+	while (raidPtr->parityLogDiskQueue.freeCommonList) {
+		c = raidPtr->parityLogDiskQueue.freeCommonList;
+		rf_mutex_destroy(&c->mutex);
+		raidPtr->parityLogDiskQueue.freeCommonList = 
+			raidPtr->parityLogDiskQueue.freeCommonList->next;
+		RF_Free(c, sizeof(RF_CommonLogData_t));
+	}
+}
+
+static void 
+rf_ShutdownParityLogging(RF_ThreadArg_t arg)
+{
+	RF_Raid_t *raidPtr;
+
+	raidPtr = (RF_Raid_t *) arg;
+	if (rf_parityLogDebug) {
+		printf("raid%d: ShutdownParityLogging\n", raidPtr->raidid);
+	}
+	/* shutdown disk thread */
+	/* This has the desirable side-effect of forcing all regions to be
+	 * reintegrated.  This is necessary since all parity log maps are
+	 * currently held in volatile memory. */
+
+	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
+	raidPtr->parityLogDiskQueue.threadState |= RF_PLOG_TERMINATE;
+	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
+	RF_SIGNAL_COND(raidPtr->parityLogDiskQueue.cond);
+	/*
+         * pLogDiskThread will now terminate when queues are cleared
+         * now wait for it to be done
+         */
+	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
+	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_SHUTDOWN)) {
+		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond, 
+			     raidPtr->parityLogDiskQueue.mutex);
+	}
+	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
+	if (rf_parityLogDebug) {
+		printf("raid%d: ShutdownParityLogging done (thread completed)\n", raidPtr->raidid);
+	}
+}
+
+int 
+rf_GetDefaultNumFloatingReconBuffersParityLogging(RF_Raid_t * raidPtr)
+{
+	return (20);
+}
+
+RF_HeadSepLimit_t 
+rf_GetDefaultHeadSepLimitParityLogging(RF_Raid_t * raidPtr)
+{
+	return (10);
+}
+/* return the region ID for a given RAID address */
+RF_RegionId_t 
+rf_MapRegionIDParityLogging(
+    RF_Raid_t * raidPtr,
+    RF_SectorNum_t address)
+{
+	RF_RegionId_t regionID;
+
+/*  regionID = address / (raidPtr->regionParityRange * raidPtr->Layout.numDataCol); */
+	regionID = address / raidPtr->regionParityRange;
+	if (regionID == rf_numParityRegions) {
+		/* last region may be larger than other regions */
+		regionID--;
+	}
+	RF_ASSERT(address >= raidPtr->regionInfo[regionID].parityStartAddr);
+	RF_ASSERT(address < raidPtr->regionInfo[regionID].parityStartAddr + 
+		  raidPtr->regionInfo[regionID].numSectorsParity);
+	RF_ASSERT(regionID < rf_numParityRegions);
+	return (regionID);
+}
+
+
+/* given a logical RAID sector, determine physical disk address of data */
+void 
+rf_MapSectorParityLogging(
+    RF_Raid_t * raidPtr,
+    RF_RaidAddr_t raidSector,
+    RF_RowCol_t * row,
+    RF_RowCol_t * col,
+    RF_SectorNum_t * diskSector,
+    int remap)
+{
+	RF_StripeNum_t SUID = raidSector / 
+		raidPtr->Layout.sectorsPerStripeUnit;
+	*row = 0;
+	/* *col = (SUID % (raidPtr->numCol -
+	 * raidPtr->Layout.numParityLogCol)); */
+	*col = SUID % raidPtr->Layout.numDataCol;
+	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * 
+		raidPtr->Layout.sectorsPerStripeUnit +
+		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
+}
+
+
+/* given a logical RAID sector, determine physical disk address of parity  */
+void 
+rf_MapParityParityLogging(
+    RF_Raid_t * raidPtr,
+    RF_RaidAddr_t raidSector,
+    RF_RowCol_t * row,
+    RF_RowCol_t * col,
+    RF_SectorNum_t * diskSector,
+    int remap)
+{
+	RF_StripeNum_t SUID = raidSector / 
+		raidPtr->Layout.sectorsPerStripeUnit;
+
+	*row = 0;
+	/* *col =
+	 * raidPtr->Layout.numDataCol-(SUID/raidPtr->Layout.numDataCol)%(raidPt
+	 * r->numCol - raidPtr->Layout.numParityLogCol); */
+	*col = raidPtr->Layout.numDataCol;
+	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * 
+		raidPtr->Layout.sectorsPerStripeUnit +
+		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
+}
+
+
+/* given a regionID and sector offset, determine the physical disk address of the parity log */
+void 
+rf_MapLogParityLogging(
+    RF_Raid_t * raidPtr,
+    RF_RegionId_t regionID,
+    RF_SectorNum_t regionOffset,
+    RF_RowCol_t * row,
+    RF_RowCol_t * col,
+    RF_SectorNum_t * startSector)
+{
+	*row = 0;
+	*col = raidPtr->numCol - 1;
+	*startSector = raidPtr->regionInfo[regionID].regionStartAddr + regionOffset;
+}
+
+
+/* given a regionID, determine the physical disk address of the logged
+   parity for that region */
+void 
+rf_MapRegionParity(
+    RF_Raid_t * raidPtr,
+    RF_RegionId_t regionID,
+    RF_RowCol_t * row,
+    RF_RowCol_t * col,
+    RF_SectorNum_t * startSector,
+    RF_SectorCount_t * numSector)
+{
+	*row = 0;
+	*col = raidPtr->numCol - 2;
+	*startSector = raidPtr->regionInfo[regionID].parityStartAddr;
+	*numSector = raidPtr->regionInfo[regionID].numSectorsParity;
+}
+
+
+/* given a logical RAID address, determine the participating disks in
+   the stripe */
+void 
+rf_IdentifyStripeParityLogging(
+    RF_Raid_t * raidPtr,
+    RF_RaidAddr_t addr,
+    RF_RowCol_t ** diskids,
+    RF_RowCol_t * outRow)
+{
+	RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, 
+							   addr);
+	RF_ParityLoggingConfigInfo_t *info = (RF_ParityLoggingConfigInfo_t *) 
+		raidPtr->Layout.layoutSpecificInfo;
+	*outRow = 0;
+	*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
+}
+
+
+void 
+rf_MapSIDToPSIDParityLogging(
+    RF_RaidLayout_t * layoutPtr,
+    RF_StripeNum_t stripeID,
+    RF_StripeNum_t * psID,
+    RF_ReconUnitNum_t * which_ru)
+{
+	*which_ru = 0;
+	*psID = stripeID;
+}
+
+
+/* select an algorithm for performing an access.  Returns two pointers,
+ * one to a function that will return information about the DAG, and
+ * another to a function that will create the dag.
+ */
+void 
+rf_ParityLoggingDagSelect(
+    RF_Raid_t * raidPtr,
+    RF_IoType_t type,
+    RF_AccessStripeMap_t * asmp,
+    RF_VoidFuncPtr * createFunc)
+{
+	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
+	RF_PhysDiskAddr_t *failedPDA = NULL;
+	RF_RowCol_t frow, fcol;
+	RF_RowStatus_t rstat;
+	int     prior_recon;
+
+	RF_ASSERT(RF_IO_IS_R_OR_W(type));
+
+	if (asmp->numDataFailed + asmp->numParityFailed > 1) {
+		RF_ERRORMSG("Multiple disks failed in a single group!  Aborting I/O operation.\n");
+		 /* *infoFunc = */ *createFunc = NULL;
+		return;
+	} else
+		if (asmp->numDataFailed + asmp->numParityFailed == 1) {
+
+			/* if under recon & already reconstructed, redirect
+			 * the access to the spare drive and eliminate the
+			 * failure indication */
+			failedPDA = asmp->failedPDAs[0];
+			frow = failedPDA->row;
+			fcol = failedPDA->col;
+			rstat = raidPtr->status[failedPDA->row];
+			prior_recon = (rstat == rf_rs_reconfigured) || (
+			    (rstat == rf_rs_reconstructing) ?
+			    rf_CheckRUReconstructed(raidPtr->reconControl[frow]->reconMap, failedPDA->startSector) : 0
+			    );
+			if (prior_recon) {
+				RF_RowCol_t or = failedPDA->row, oc = failedPDA->col;
+				RF_SectorNum_t oo = failedPDA->startSector;
+				if (layoutPtr->map->flags & 
+				    RF_DISTRIBUTE_SPARE) {	
+					/* redirect to dist spare space */
+
+					if (failedPDA == asmp->parityInfo) {
+
+						/* parity has failed */
+						(layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
+						    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
+
+						if (asmp->parityInfo->next) {	/* redir 2nd component,
+										 * if any */
+							RF_PhysDiskAddr_t *p = asmp->parityInfo->next;
+							RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit;
+							p->row = failedPDA->row;
+							p->col = failedPDA->col;
+							p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) +
+							    SUoffs;	/* cheating:
+									 * startSector is not
+									 * really a RAID address */
+						}
+					} else
+						if (asmp->parityInfo->next && failedPDA == asmp->parityInfo->next) {
+							RF_ASSERT(0);	/* should not ever
+									 * happen */
+						} else {
+
+							/* data has failed */
+							(layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
+							    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
+
+						}
+
+				} else {	
+					/* redirect to dedicated spare space */
+
+					failedPDA->row = raidPtr->Disks[frow][fcol].spareRow;
+					failedPDA->col = raidPtr->Disks[frow][fcol].spareCol;
+
+					/* the parity may have two distinct
+					 * components, both of which may need
+					 * to be redirected */
+					if (asmp->parityInfo->next) {
+						if (failedPDA == asmp->parityInfo) {
+							failedPDA->next->row = failedPDA->row;
+							failedPDA->next->col = failedPDA->col;
+						} else
+							if (failedPDA == asmp->parityInfo->next) {	/* paranoid:  should never occur */
+								asmp->parityInfo->row = failedPDA->row;
+								asmp->parityInfo->col = failedPDA->col;
+							}
+					}
+				}
+
+				RF_ASSERT(failedPDA->col != -1);
+
+				if (rf_dagDebug || rf_mapDebug) {
+					printf("raid%d: Redirected type '%c' r %d c %d o %ld -> r %d c %d o %ld\n",
+					    raidPtr->raidid, type, or, oc, (long) oo, failedPDA->row, failedPDA->col, (long) failedPDA->startSector);
+				}
+				asmp->numDataFailed = asmp->numParityFailed = 0;
+			}
+		}
+	if (type == RF_IO_TYPE_READ) {
+
+		if (asmp->numDataFailed == 0)
+			*createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG;
+		else
+			*createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG;
+
+	} else {
+
+
+		/* if mirroring, always use large writes.  If the access
+		 * requires two distinct parity updates, always do a small
+		 * write.  If the stripe contains a failure but the access
+		 * does not, do a small write. The first conditional
+		 * (numStripeUnitsAccessed <= numDataCol/2) uses a
+		 * less-than-or-equal rather than just a less-than because
+		 * when G is 3 or 4, numDataCol/2 is 1, and I want
+		 * single-stripe-unit updates to use just one disk. */
+		if ((asmp->numDataFailed + asmp->numParityFailed) == 0) {
+			if (((asmp->numStripeUnitsAccessed <= 
+			      (layoutPtr->numDataCol / 2)) && 
+			     (layoutPtr->numDataCol != 1)) ||
+			    (asmp->parityInfo->next != NULL) || 
+			    rf_CheckStripeForFailures(raidPtr, asmp)) {
+				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingSmallWriteDAG;
+			} else
+				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingLargeWriteDAG;
+		} else
+			if (asmp->numParityFailed == 1)
+				*createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG;
+			else
+				if (asmp->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit)
+					*createFunc = NULL;
+				else
+					*createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG;
+	}
+}
+#endif				/* RF_INCLUDE_PARITYLOGGING > 0 */