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rf_paritylogging.c revision 1.21
      1 /*	$NetBSD: rf_paritylogging.c,v 1.21 2003/12/29 05:48:13 oster Exp $	*/
      2 /*
      3  * Copyright (c) 1995 Carnegie-Mellon University.
      4  * All rights reserved.
      5  *
      6  * Author: William V. Courtright II
      7  *
      8  * Permission to use, copy, modify and distribute this software and
      9  * its documentation is hereby granted, provided that both the copyright
     10  * notice and this permission notice appear in all copies of the
     11  * software, derivative works or modified versions, and any portions
     12  * thereof, and that both notices appear in supporting documentation.
     13  *
     14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     16  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     17  *
     18  * Carnegie Mellon requests users of this software to return to
     19  *
     20  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     21  *  School of Computer Science
     22  *  Carnegie Mellon University
     23  *  Pittsburgh PA 15213-3890
     24  *
     25  * any improvements or extensions that they make and grant Carnegie the
     26  * rights to redistribute these changes.
     27  */
     28 
     29 
     30 /*
     31   parity logging configuration, dag selection, and mapping is implemented here
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 __KERNEL_RCSID(0, "$NetBSD: rf_paritylogging.c,v 1.21 2003/12/29 05:48:13 oster Exp $");
     36 
     37 #include "rf_archs.h"
     38 
     39 #if RF_INCLUDE_PARITYLOGGING > 0
     40 
     41 #include <dev/raidframe/raidframevar.h>
     42 
     43 #include "rf_raid.h"
     44 #include "rf_dag.h"
     45 #include "rf_dagutils.h"
     46 #include "rf_dagfuncs.h"
     47 #include "rf_dagffrd.h"
     48 #include "rf_dagffwr.h"
     49 #include "rf_dagdegrd.h"
     50 #include "rf_dagdegwr.h"
     51 #include "rf_paritylog.h"
     52 #include "rf_paritylogDiskMgr.h"
     53 #include "rf_paritylogging.h"
     54 #include "rf_parityloggingdags.h"
     55 #include "rf_general.h"
     56 #include "rf_map.h"
     57 #include "rf_utils.h"
     58 #include "rf_shutdown.h"
     59 
     60 typedef struct RF_ParityLoggingConfigInfo_s {
     61 	RF_RowCol_t **stripeIdentifier;	/* filled in at config time & used by
     62 					 * IdentifyStripe */
     63 }       RF_ParityLoggingConfigInfo_t;
     64 
     65 static void FreeRegionInfo(RF_Raid_t * raidPtr, RF_RegionId_t regionID);
     66 static void rf_ShutdownParityLogging(RF_ThreadArg_t arg);
     67 static void rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg);
     68 static void rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg);
     69 static void rf_ShutdownParityLoggingRegionBufferPool(RF_ThreadArg_t arg);
     70 static void rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg);
     71 static void rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg);
     72 
     73 int
     74 rf_ConfigureParityLogging(
     75     RF_ShutdownList_t ** listp,
     76     RF_Raid_t * raidPtr,
     77     RF_Config_t * cfgPtr)
     78 {
     79 	int     i, j, startdisk, rc;
     80 	RF_SectorCount_t totalLogCapacity, fragmentation, lastRegionCapacity;
     81 	RF_SectorCount_t parityBufferCapacity, maxRegionParityRange;
     82 	RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
     83 	RF_ParityLoggingConfigInfo_t *info;
     84 	RF_ParityLog_t *l = NULL, *next;
     85 	caddr_t lHeapPtr;
     86 
     87 	if (rf_numParityRegions <= 0)
     88 		return(EINVAL);
     89 
     90 	/*
     91          * We create multiple entries on the shutdown list here, since
     92          * this configuration routine is fairly complicated in and of
     93          * itself, and this makes backing out of a failed configuration
     94          * much simpler.
     95          */
     96 
     97 	raidPtr->numSectorsPerLog = RF_DEFAULT_NUM_SECTORS_PER_LOG;
     98 
     99 	/* create a parity logging configuration structure */
    100 	RF_MallocAndAdd(info, sizeof(RF_ParityLoggingConfigInfo_t),
    101 			(RF_ParityLoggingConfigInfo_t *),
    102 			raidPtr->cleanupList);
    103 	if (info == NULL)
    104 		return (ENOMEM);
    105 	layoutPtr->layoutSpecificInfo = (void *) info;
    106 
    107 	/* the stripe identifier must identify the disks in each stripe, IN
    108 	 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
    109 	info->stripeIdentifier = rf_make_2d_array((raidPtr->numCol),
    110 						  (raidPtr->numCol),
    111 						  raidPtr->cleanupList);
    112 	if (info->stripeIdentifier == NULL)
    113 		return (ENOMEM);
    114 
    115 	startdisk = 0;
    116 	for (i = 0; i < (raidPtr->numCol); i++) {
    117 		for (j = 0; j < (raidPtr->numCol); j++) {
    118 			info->stripeIdentifier[i][j] = (startdisk + j) %
    119 				(raidPtr->numCol - 1);
    120 		}
    121 		if ((--startdisk) < 0)
    122 			startdisk = raidPtr->numCol - 1 - 1;
    123 	}
    124 
    125 	/* fill in the remaining layout parameters */
    126 	layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
    127 	layoutPtr->numParityCol = 1;
    128 	layoutPtr->numParityLogCol = 1;
    129 	layoutPtr->numDataCol = raidPtr->numCol - layoutPtr->numParityCol -
    130 		layoutPtr->numParityLogCol;
    131 	layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol *
    132 		layoutPtr->sectorsPerStripeUnit;
    133 	layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;
    134 	raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk *
    135 		layoutPtr->sectorsPerStripeUnit;
    136 
    137 	raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk *
    138 		layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
    139 
    140 	/* configure parity log parameters
    141 	 *
    142 	 * parameter               comment/constraints
    143 	 * -------------------------------------------
    144 	 * numParityRegions*       all regions (except possibly last)
    145 	 *                         of equal size
    146 	 * totalInCoreLogCapacity* amount of memory in bytes available
    147 	 *                         for in-core logs (default 1 MB)
    148 	 * numSectorsPerLog#       capacity of an in-core log in sectors
    149 	 *                         (1 * disk track)
    150 	 * numParityLogs           total number of in-core logs,
    151 	 *                         should be at least numParityRegions
    152 	 * regionLogCapacity       size of a region log (except possibly
    153 	 *                         last one) in sectors
    154 	 * totalLogCapacity        total amount of log space in sectors
    155 	 *
    156 	 * where '*' denotes a user settable parameter.
    157 	 * Note that logs are fixed to be the size of a disk track,
    158 	 * value #defined in rf_paritylog.h
    159 	 *
    160 	 */
    161 
    162 	totalLogCapacity = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit * layoutPtr->numParityLogCol;
    163 	raidPtr->regionLogCapacity = totalLogCapacity / rf_numParityRegions;
    164 	if (rf_parityLogDebug)
    165 		printf("bytes per sector %d\n", raidPtr->bytesPerSector);
    166 
    167 	/* reduce fragmentation within a disk region by adjusting the number
    168 	 * of regions in an attempt to allow an integral number of logs to fit
    169 	 * into a disk region */
    170 	fragmentation = raidPtr->regionLogCapacity % raidPtr->numSectorsPerLog;
    171 	if (fragmentation > 0)
    172 		for (i = 1; i < (raidPtr->numSectorsPerLog / 2); i++) {
    173 			if (((totalLogCapacity / (rf_numParityRegions + i)) %
    174 			     raidPtr->numSectorsPerLog) < fragmentation) {
    175 				rf_numParityRegions++;
    176 				raidPtr->regionLogCapacity = totalLogCapacity /
    177 					rf_numParityRegions;
    178 				fragmentation = raidPtr->regionLogCapacity %
    179 					raidPtr->numSectorsPerLog;
    180 			}
    181 			if (((totalLogCapacity / (rf_numParityRegions - i)) %
    182 			     raidPtr->numSectorsPerLog) < fragmentation) {
    183 				rf_numParityRegions--;
    184 				raidPtr->regionLogCapacity = totalLogCapacity /
    185 					rf_numParityRegions;
    186 				fragmentation = raidPtr->regionLogCapacity %
    187 					raidPtr->numSectorsPerLog;
    188 			}
    189 		}
    190 	/* ensure integral number of regions per log */
    191 	raidPtr->regionLogCapacity = (raidPtr->regionLogCapacity /
    192 				      raidPtr->numSectorsPerLog) *
    193 		raidPtr->numSectorsPerLog;
    194 
    195 	raidPtr->numParityLogs = rf_totalInCoreLogCapacity /
    196 		(raidPtr->bytesPerSector * raidPtr->numSectorsPerLog);
    197 	/* to avoid deadlock, must ensure that enough logs exist for each
    198 	 * region to have one simultaneously */
    199 	if (raidPtr->numParityLogs < rf_numParityRegions)
    200 		raidPtr->numParityLogs = rf_numParityRegions;
    201 
    202 	/* create region information structs */
    203 	printf("Allocating %d bytes for in-core parity region info\n",
    204 	       (int) (rf_numParityRegions * sizeof(RF_RegionInfo_t)));
    205 	RF_Malloc(raidPtr->regionInfo,
    206 		  (rf_numParityRegions * sizeof(RF_RegionInfo_t)),
    207 		  (RF_RegionInfo_t *));
    208 	if (raidPtr->regionInfo == NULL)
    209 		return (ENOMEM);
    210 
    211 	/* last region may not be full capacity */
    212 	lastRegionCapacity = raidPtr->regionLogCapacity;
    213 	while ((rf_numParityRegions - 1) * raidPtr->regionLogCapacity +
    214 	       lastRegionCapacity > totalLogCapacity)
    215 		lastRegionCapacity = lastRegionCapacity -
    216 			raidPtr->numSectorsPerLog;
    217 
    218 	raidPtr->regionParityRange = raidPtr->sectorsPerDisk /
    219 		rf_numParityRegions;
    220 	maxRegionParityRange = raidPtr->regionParityRange;
    221 
    222 /* i can't remember why this line is in the code -wvcii 6/30/95 */
    223 /*  if (raidPtr->sectorsPerDisk % rf_numParityRegions > 0)
    224     regionParityRange++; */
    225 
    226 	/* build pool of unused parity logs */
    227 	printf("Allocating %d bytes for %d parity logs\n",
    228 	       raidPtr->numParityLogs * raidPtr->numSectorsPerLog *
    229 	       raidPtr->bytesPerSector,
    230 	       raidPtr->numParityLogs);
    231 	RF_Malloc(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    232 		  raidPtr->numSectorsPerLog * raidPtr->bytesPerSector,
    233 		  (caddr_t));
    234 	if (raidPtr->parityLogBufferHeap == NULL)
    235 		return (ENOMEM);
    236 	lHeapPtr = raidPtr->parityLogBufferHeap;
    237 	rc = rf_mutex_init(&raidPtr->parityLogPool.mutex);
    238 	if (rc) {
    239 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    240 		RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    241 			raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
    242 		return (ENOMEM);
    243 	}
    244 	for (i = 0; i < raidPtr->numParityLogs; i++) {
    245 		if (i == 0) {
    246 			RF_Malloc(raidPtr->parityLogPool.parityLogs,
    247 				  sizeof(RF_ParityLog_t), (RF_ParityLog_t *));
    248 			if (raidPtr->parityLogPool.parityLogs == NULL) {
    249 				RF_Free(raidPtr->parityLogBufferHeap,
    250 					raidPtr->numParityLogs *
    251 					raidPtr->numSectorsPerLog *
    252 					raidPtr->bytesPerSector);
    253 				return (ENOMEM);
    254 			}
    255 			l = raidPtr->parityLogPool.parityLogs;
    256 		} else {
    257 			RF_Malloc(l->next, sizeof(RF_ParityLog_t),
    258 				  (RF_ParityLog_t *));
    259 			if (l->next == NULL) {
    260 				RF_Free(raidPtr->parityLogBufferHeap,
    261 					raidPtr->numParityLogs *
    262 					raidPtr->numSectorsPerLog *
    263 					raidPtr->bytesPerSector);
    264 				for (l = raidPtr->parityLogPool.parityLogs;
    265 				     l;
    266 				     l = next) {
    267 					next = l->next;
    268 					if (l->records)
    269 						RF_Free(l->records, (raidPtr->numSectorsPerLog * sizeof(RF_ParityLogRecord_t)));
    270 					RF_Free(l, sizeof(RF_ParityLog_t));
    271 				}
    272 				return (ENOMEM);
    273 			}
    274 			l = l->next;
    275 		}
    276 		l->bufPtr = lHeapPtr;
    277 		lHeapPtr += raidPtr->numSectorsPerLog *
    278 			raidPtr->bytesPerSector;
    279 		RF_Malloc(l->records, (raidPtr->numSectorsPerLog *
    280 				       sizeof(RF_ParityLogRecord_t)),
    281 			  (RF_ParityLogRecord_t *));
    282 		if (l->records == NULL) {
    283 			RF_Free(raidPtr->parityLogBufferHeap,
    284 				raidPtr->numParityLogs *
    285 				raidPtr->numSectorsPerLog *
    286 				raidPtr->bytesPerSector);
    287 			for (l = raidPtr->parityLogPool.parityLogs;
    288 			     l;
    289 			     l = next) {
    290 				next = l->next;
    291 				if (l->records)
    292 					RF_Free(l->records,
    293 						(raidPtr->numSectorsPerLog *
    294 						 sizeof(RF_ParityLogRecord_t)));
    295 				RF_Free(l, sizeof(RF_ParityLog_t));
    296 			}
    297 			return (ENOMEM);
    298 		}
    299 	}
    300 	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLoggingPool, raidPtr);
    301 	if (rc) {
    302 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    303 		    __LINE__, rc);
    304 		rf_ShutdownParityLoggingPool(raidPtr);
    305 		return (rc);
    306 	}
    307 	/* build pool of region buffers */
    308 	rc = rf_mutex_init(&raidPtr->regionBufferPool.mutex);
    309 	if (rc) {
    310 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    311 		return (ENOMEM);
    312 	}
    313 	raidPtr->regionBufferPool.cond = 0;
    314 	raidPtr->regionBufferPool.bufferSize = raidPtr->regionLogCapacity *
    315 		raidPtr->bytesPerSector;
    316 	printf("regionBufferPool.bufferSize %d\n",
    317 	       raidPtr->regionBufferPool.bufferSize);
    318 
    319 	/* for now, only one region at a time may be reintegrated */
    320 	raidPtr->regionBufferPool.totalBuffers = 1;
    321 
    322 	raidPtr->regionBufferPool.availableBuffers =
    323 		raidPtr->regionBufferPool.totalBuffers;
    324 	raidPtr->regionBufferPool.availBuffersIndex = 0;
    325 	raidPtr->regionBufferPool.emptyBuffersIndex = 0;
    326 	printf("Allocating %d bytes for regionBufferPool\n",
    327 	       (int) (raidPtr->regionBufferPool.totalBuffers *
    328 		      sizeof(caddr_t)));
    329 	RF_Malloc(raidPtr->regionBufferPool.buffers,
    330 		  raidPtr->regionBufferPool.totalBuffers * sizeof(caddr_t),
    331 		  (caddr_t *));
    332 	if (raidPtr->regionBufferPool.buffers == NULL) {
    333 		return (ENOMEM);
    334 	}
    335 	for (i = 0; i < raidPtr->regionBufferPool.totalBuffers; i++) {
    336 		printf("Allocating %d bytes for regionBufferPool#%d\n",
    337 		       (int) (raidPtr->regionBufferPool.bufferSize *
    338 			      sizeof(char)), i);
    339 		RF_Malloc(raidPtr->regionBufferPool.buffers[i],
    340 			  raidPtr->regionBufferPool.bufferSize * sizeof(char),
    341 			  (caddr_t));
    342 		if (raidPtr->regionBufferPool.buffers[i] == NULL) {
    343 			for (j = 0; j < i; j++) {
    344 				RF_Free(raidPtr->regionBufferPool.buffers[i],
    345 					raidPtr->regionBufferPool.bufferSize *
    346 					sizeof(char));
    347 			}
    348 			RF_Free(raidPtr->regionBufferPool.buffers,
    349 				raidPtr->regionBufferPool.totalBuffers *
    350 				sizeof(caddr_t));
    351 			return (ENOMEM);
    352 		}
    353 		printf("raidPtr->regionBufferPool.buffers[%d] = %lx\n", i,
    354 		    (long) raidPtr->regionBufferPool.buffers[i]);
    355 	}
    356 	rc = rf_ShutdownCreate(listp,
    357 			       rf_ShutdownParityLoggingRegionBufferPool,
    358 			       raidPtr);
    359 	if (rc) {
    360 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    361 		    __LINE__, rc);
    362 		rf_ShutdownParityLoggingRegionBufferPool(raidPtr);
    363 		return (rc);
    364 	}
    365 	/* build pool of parity buffers */
    366 	parityBufferCapacity = maxRegionParityRange;
    367 	rc = rf_mutex_init(&raidPtr->parityBufferPool.mutex);
    368 	if (rc) {
    369 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    370 		return (rc);
    371 	}
    372 	raidPtr->parityBufferPool.cond = 0;
    373 	raidPtr->parityBufferPool.bufferSize = parityBufferCapacity *
    374 		raidPtr->bytesPerSector;
    375 	printf("parityBufferPool.bufferSize %d\n",
    376 	       raidPtr->parityBufferPool.bufferSize);
    377 
    378 	/* for now, only one region at a time may be reintegrated */
    379 	raidPtr->parityBufferPool.totalBuffers = 1;
    380 
    381 	raidPtr->parityBufferPool.availableBuffers =
    382 		raidPtr->parityBufferPool.totalBuffers;
    383 	raidPtr->parityBufferPool.availBuffersIndex = 0;
    384 	raidPtr->parityBufferPool.emptyBuffersIndex = 0;
    385 	printf("Allocating %d bytes for parityBufferPool of %d units\n",
    386 	       (int) (raidPtr->parityBufferPool.totalBuffers *
    387 		      sizeof(caddr_t)),
    388 	       raidPtr->parityBufferPool.totalBuffers );
    389 	RF_Malloc(raidPtr->parityBufferPool.buffers,
    390 		  raidPtr->parityBufferPool.totalBuffers * sizeof(caddr_t),
    391 		  (caddr_t *));
    392 	if (raidPtr->parityBufferPool.buffers == NULL) {
    393 		return (ENOMEM);
    394 	}
    395 	for (i = 0; i < raidPtr->parityBufferPool.totalBuffers; i++) {
    396 		printf("Allocating %d bytes for parityBufferPool#%d\n",
    397 		       (int) (raidPtr->parityBufferPool.bufferSize *
    398 			      sizeof(char)),i);
    399 		RF_Malloc(raidPtr->parityBufferPool.buffers[i],
    400 			  raidPtr->parityBufferPool.bufferSize * sizeof(char),
    401 			  (caddr_t));
    402 		if (raidPtr->parityBufferPool.buffers == NULL) {
    403 			for (j = 0; j < i; j++) {
    404 				RF_Free(raidPtr->parityBufferPool.buffers[i],
    405 					raidPtr->regionBufferPool.bufferSize *
    406 					sizeof(char));
    407 			}
    408 			RF_Free(raidPtr->parityBufferPool.buffers,
    409 				raidPtr->regionBufferPool.totalBuffers *
    410 				sizeof(caddr_t));
    411 			return (ENOMEM);
    412 		}
    413 		printf("parityBufferPool.buffers[%d] = %lx\n", i,
    414 		    (long) raidPtr->parityBufferPool.buffers[i]);
    415 	}
    416 	rc = rf_ShutdownCreate(listp,
    417 			       rf_ShutdownParityLoggingParityBufferPool,
    418 			       raidPtr);
    419 	if (rc) {
    420 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    421 		    __LINE__, rc);
    422 		rf_ShutdownParityLoggingParityBufferPool(raidPtr);
    423 		return (rc);
    424 	}
    425 	/* initialize parityLogDiskQueue */
    426 	rf_mutex_init(&raidPtr->parityLogDiskQueue.mutex);
    427 	raidPtr->parityLogDiskQueue.cond = 0;
    428 	raidPtr->parityLogDiskQueue.flushQueue = NULL;
    429 	raidPtr->parityLogDiskQueue.reintQueue = NULL;
    430 	raidPtr->parityLogDiskQueue.bufHead = NULL;
    431 	raidPtr->parityLogDiskQueue.bufTail = NULL;
    432 	raidPtr->parityLogDiskQueue.reintHead = NULL;
    433 	raidPtr->parityLogDiskQueue.reintTail = NULL;
    434 	raidPtr->parityLogDiskQueue.logBlockHead = NULL;
    435 	raidPtr->parityLogDiskQueue.logBlockTail = NULL;
    436 	raidPtr->parityLogDiskQueue.reintBlockHead = NULL;
    437 	raidPtr->parityLogDiskQueue.reintBlockTail = NULL;
    438 	raidPtr->parityLogDiskQueue.freeDataList = NULL;
    439 	raidPtr->parityLogDiskQueue.freeCommonList = NULL;
    440 
    441 	rc = rf_ShutdownCreate(listp,
    442 			       rf_ShutdownParityLoggingDiskQueue,
    443 			       raidPtr);
    444 	if (rc) {
    445 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    446 		    __LINE__, rc);
    447 		return (rc);
    448 	}
    449 	for (i = 0; i < rf_numParityRegions; i++) {
    450 		rc = rf_mutex_init(&raidPtr->regionInfo[i].mutex);
    451 		if (rc) {
    452 			rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    453 			for (j = 0; j < i; j++)
    454 				FreeRegionInfo(raidPtr, j);
    455 			RF_Free(raidPtr->regionInfo,
    456 				(rf_numParityRegions *
    457 				 sizeof(RF_RegionInfo_t)));
    458 			return (ENOMEM);
    459 		}
    460 		rc = rf_mutex_init(&raidPtr->regionInfo[i].reintMutex);
    461 		if (rc) {
    462 			rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    463 			for (j = 0; j < i; j++)
    464 				FreeRegionInfo(raidPtr, j);
    465 			RF_Free(raidPtr->regionInfo,
    466 				(rf_numParityRegions *
    467 				 sizeof(RF_RegionInfo_t)));
    468 			return (ENOMEM);
    469 		}
    470 		raidPtr->regionInfo[i].reintInProgress = RF_FALSE;
    471 		raidPtr->regionInfo[i].regionStartAddr =
    472 			raidPtr->regionLogCapacity * i;
    473 		raidPtr->regionInfo[i].parityStartAddr =
    474 			raidPtr->regionParityRange * i;
    475 		if (i < rf_numParityRegions - 1) {
    476 			raidPtr->regionInfo[i].capacity =
    477 				raidPtr->regionLogCapacity;
    478 			raidPtr->regionInfo[i].numSectorsParity =
    479 				raidPtr->regionParityRange;
    480 		} else {
    481 			raidPtr->regionInfo[i].capacity =
    482 				lastRegionCapacity;
    483 			raidPtr->regionInfo[i].numSectorsParity =
    484 				raidPtr->sectorsPerDisk -
    485 				raidPtr->regionParityRange * i;
    486 			if (raidPtr->regionInfo[i].numSectorsParity >
    487 			    maxRegionParityRange)
    488 				maxRegionParityRange =
    489 					raidPtr->regionInfo[i].numSectorsParity;
    490 		}
    491 		raidPtr->regionInfo[i].diskCount = 0;
    492 		RF_ASSERT(raidPtr->regionInfo[i].capacity +
    493 			  raidPtr->regionInfo[i].regionStartAddr <=
    494 			  totalLogCapacity);
    495 		RF_ASSERT(raidPtr->regionInfo[i].parityStartAddr +
    496 			  raidPtr->regionInfo[i].numSectorsParity <=
    497 			  raidPtr->sectorsPerDisk);
    498 		printf("Allocating %d bytes for region %d\n",
    499 		       (int) (raidPtr->regionInfo[i].capacity *
    500 			   sizeof(RF_DiskMap_t)), i);
    501 		RF_Malloc(raidPtr->regionInfo[i].diskMap,
    502 			  (raidPtr->regionInfo[i].capacity *
    503 			   sizeof(RF_DiskMap_t)),
    504 			  (RF_DiskMap_t *));
    505 		if (raidPtr->regionInfo[i].diskMap == NULL) {
    506 			for (j = 0; j < i; j++)
    507 				FreeRegionInfo(raidPtr, j);
    508 			RF_Free(raidPtr->regionInfo,
    509 				(rf_numParityRegions *
    510 				 sizeof(RF_RegionInfo_t)));
    511 			return (ENOMEM);
    512 		}
    513 		raidPtr->regionInfo[i].loggingEnabled = RF_FALSE;
    514 		raidPtr->regionInfo[i].coreLog = NULL;
    515 	}
    516 	rc = rf_ShutdownCreate(listp,
    517 			       rf_ShutdownParityLoggingRegionInfo,
    518 			       raidPtr);
    519 	if (rc) {
    520 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    521 		    __LINE__, rc);
    522 		rf_ShutdownParityLoggingRegionInfo(raidPtr);
    523 		return (rc);
    524 	}
    525 	RF_ASSERT(raidPtr->parityLogDiskQueue.threadState == 0);
    526 	raidPtr->parityLogDiskQueue.threadState = RF_PLOG_CREATED;
    527 	rc = RF_CREATE_THREAD(raidPtr->pLogDiskThreadHandle,
    528 			      rf_ParityLoggingDiskManager, raidPtr,"rf_log");
    529 	if (rc) {
    530 		raidPtr->parityLogDiskQueue.threadState = 0;
    531 		RF_ERRORMSG3("Unable to create parity logging disk thread file %s line %d rc=%d\n",
    532 		    __FILE__, __LINE__, rc);
    533 		return (ENOMEM);
    534 	}
    535 	/* wait for thread to start */
    536 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    537 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_RUNNING)) {
    538 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    539 			     raidPtr->parityLogDiskQueue.mutex);
    540 	}
    541 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    542 
    543 	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLogging, raidPtr);
    544 	if (rc) {
    545 		RF_ERRORMSG1("Got rc=%d adding parity logging shutdown event\n", rc);
    546 		rf_ShutdownParityLogging(raidPtr);
    547 		return (rc);
    548 	}
    549 	if (rf_parityLogDebug) {
    550 		printf("                            size of disk log in sectors: %d\n",
    551 		    (int) totalLogCapacity);
    552 		printf("                            total number of parity regions is %d\n", (int) rf_numParityRegions);
    553 		printf("                            nominal sectors of log per parity region is %d\n", (int) raidPtr->regionLogCapacity);
    554 		printf("                            nominal region fragmentation is %d sectors\n", (int) fragmentation);
    555 		printf("                            total number of parity logs is %d\n", raidPtr->numParityLogs);
    556 		printf("                            parity log size is %d sectors\n", raidPtr->numSectorsPerLog);
    557 		printf("                            total in-core log space is %d bytes\n", (int) rf_totalInCoreLogCapacity);
    558 	}
    559 	rf_EnableParityLogging(raidPtr);
    560 
    561 	return (0);
    562 }
    563 
    564 static void
    565 FreeRegionInfo(
    566     RF_Raid_t * raidPtr,
    567     RF_RegionId_t regionID)
    568 {
    569 	RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    570 	RF_Free(raidPtr->regionInfo[regionID].diskMap,
    571 		(raidPtr->regionInfo[regionID].capacity *
    572 		 sizeof(RF_DiskMap_t)));
    573 	if (!rf_forceParityLogReint && raidPtr->regionInfo[regionID].coreLog) {
    574 		rf_ReleaseParityLogs(raidPtr,
    575 				     raidPtr->regionInfo[regionID].coreLog);
    576 		raidPtr->regionInfo[regionID].coreLog = NULL;
    577 	} else {
    578 		RF_ASSERT(raidPtr->regionInfo[regionID].coreLog == NULL);
    579 		RF_ASSERT(raidPtr->regionInfo[regionID].diskCount == 0);
    580 	}
    581 	RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    582 }
    583 
    584 
    585 static void
    586 FreeParityLogQueue(
    587     RF_Raid_t * raidPtr,
    588     RF_ParityLogQueue_t * queue)
    589 {
    590 	RF_ParityLog_t *l1, *l2;
    591 
    592 	RF_LOCK_MUTEX(queue->mutex);
    593 	l1 = queue->parityLogs;
    594 	while (l1) {
    595 		l2 = l1;
    596 		l1 = l2->next;
    597 		RF_Free(l2->records, (raidPtr->numSectorsPerLog *
    598 				      sizeof(RF_ParityLogRecord_t)));
    599 		RF_Free(l2, sizeof(RF_ParityLog_t));
    600 	}
    601 	RF_UNLOCK_MUTEX(queue->mutex);
    602 }
    603 
    604 
    605 static void
    606 FreeRegionBufferQueue(RF_RegionBufferQueue_t * queue)
    607 {
    608 	int     i;
    609 
    610 	RF_LOCK_MUTEX(queue->mutex);
    611 	if (queue->availableBuffers != queue->totalBuffers) {
    612 		printf("Attempt to free region queue which is still in use!\n");
    613 		RF_ASSERT(0);
    614 	}
    615 	for (i = 0; i < queue->totalBuffers; i++)
    616 		RF_Free(queue->buffers[i], queue->bufferSize);
    617 	RF_Free(queue->buffers, queue->totalBuffers * sizeof(caddr_t));
    618 	RF_UNLOCK_MUTEX(queue->mutex);
    619 }
    620 
    621 static void
    622 rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg)
    623 {
    624 	RF_Raid_t *raidPtr;
    625 	RF_RegionId_t i;
    626 
    627 	raidPtr = (RF_Raid_t *) arg;
    628 	if (rf_parityLogDebug) {
    629 		printf("raid%d: ShutdownParityLoggingRegionInfo\n",
    630 		       raidPtr->raidid);
    631 	}
    632 	/* free region information structs */
    633 	for (i = 0; i < rf_numParityRegions; i++)
    634 		FreeRegionInfo(raidPtr, i);
    635 	RF_Free(raidPtr->regionInfo, (rf_numParityRegions *
    636 				      sizeof(raidPtr->regionInfo)));
    637 	raidPtr->regionInfo = NULL;
    638 }
    639 
    640 static void
    641 rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg)
    642 {
    643 	RF_Raid_t *raidPtr;
    644 
    645 	raidPtr = (RF_Raid_t *) arg;
    646 	if (rf_parityLogDebug) {
    647 		printf("raid%d: ShutdownParityLoggingPool\n", raidPtr->raidid);
    648 	}
    649 	/* free contents of parityLogPool */
    650 	FreeParityLogQueue(raidPtr, &raidPtr->parityLogPool);
    651 	RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    652 		raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
    653 }
    654 
    655 static void
    656 rf_ShutdownParityLoggingRegionBufferPool(RF_ThreadArg_t arg)
    657 {
    658 	RF_Raid_t *raidPtr;
    659 
    660 	raidPtr = (RF_Raid_t *) arg;
    661 	if (rf_parityLogDebug) {
    662 		printf("raid%d: ShutdownParityLoggingRegionBufferPool\n",
    663 		       raidPtr->raidid);
    664 	}
    665 	FreeRegionBufferQueue(&raidPtr->regionBufferPool);
    666 }
    667 
    668 static void
    669 rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg)
    670 {
    671 	RF_Raid_t *raidPtr;
    672 
    673 	raidPtr = (RF_Raid_t *) arg;
    674 	if (rf_parityLogDebug) {
    675 		printf("raid%d: ShutdownParityLoggingParityBufferPool\n",
    676 		       raidPtr->raidid);
    677 	}
    678 	FreeRegionBufferQueue(&raidPtr->parityBufferPool);
    679 }
    680 
    681 static void
    682 rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg)
    683 {
    684 	RF_ParityLogData_t *d;
    685 	RF_CommonLogData_t *c;
    686 	RF_Raid_t *raidPtr;
    687 
    688 	raidPtr = (RF_Raid_t *) arg;
    689 	if (rf_parityLogDebug) {
    690 		printf("raid%d: ShutdownParityLoggingDiskQueue\n",
    691 		       raidPtr->raidid);
    692 	}
    693 	/* free disk manager stuff */
    694 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufHead == NULL);
    695 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufTail == NULL);
    696 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintHead == NULL);
    697 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintTail == NULL);
    698 	while (raidPtr->parityLogDiskQueue.freeDataList) {
    699 		d = raidPtr->parityLogDiskQueue.freeDataList;
    700 		raidPtr->parityLogDiskQueue.freeDataList =
    701 			raidPtr->parityLogDiskQueue.freeDataList->next;
    702 		RF_Free(d, sizeof(RF_ParityLogData_t));
    703 	}
    704 	while (raidPtr->parityLogDiskQueue.freeCommonList) {
    705 		c = raidPtr->parityLogDiskQueue.freeCommonList;
    706 		raidPtr->parityLogDiskQueue.freeCommonList =
    707 			raidPtr->parityLogDiskQueue.freeCommonList->next;
    708 		RF_Free(c, sizeof(RF_CommonLogData_t));
    709 	}
    710 }
    711 
    712 static void
    713 rf_ShutdownParityLogging(RF_ThreadArg_t arg)
    714 {
    715 	RF_Raid_t *raidPtr;
    716 
    717 	raidPtr = (RF_Raid_t *) arg;
    718 	if (rf_parityLogDebug) {
    719 		printf("raid%d: ShutdownParityLogging\n", raidPtr->raidid);
    720 	}
    721 	/* shutdown disk thread */
    722 	/* This has the desirable side-effect of forcing all regions to be
    723 	 * reintegrated.  This is necessary since all parity log maps are
    724 	 * currently held in volatile memory. */
    725 
    726 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    727 	raidPtr->parityLogDiskQueue.threadState |= RF_PLOG_TERMINATE;
    728 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    729 	RF_SIGNAL_COND(raidPtr->parityLogDiskQueue.cond);
    730 	/*
    731          * pLogDiskThread will now terminate when queues are cleared
    732          * now wait for it to be done
    733          */
    734 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    735 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_SHUTDOWN)) {
    736 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    737 			     raidPtr->parityLogDiskQueue.mutex);
    738 	}
    739 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    740 	if (rf_parityLogDebug) {
    741 		printf("raid%d: ShutdownParityLogging done (thread completed)\n", raidPtr->raidid);
    742 	}
    743 }
    744 
    745 int
    746 rf_GetDefaultNumFloatingReconBuffersParityLogging(RF_Raid_t * raidPtr)
    747 {
    748 	return (20);
    749 }
    750 
    751 RF_HeadSepLimit_t
    752 rf_GetDefaultHeadSepLimitParityLogging(RF_Raid_t * raidPtr)
    753 {
    754 	return (10);
    755 }
    756 /* return the region ID for a given RAID address */
    757 RF_RegionId_t
    758 rf_MapRegionIDParityLogging(
    759     RF_Raid_t * raidPtr,
    760     RF_SectorNum_t address)
    761 {
    762 	RF_RegionId_t regionID;
    763 
    764 /*  regionID = address / (raidPtr->regionParityRange * raidPtr->Layout.numDataCol); */
    765 	regionID = address / raidPtr->regionParityRange;
    766 	if (regionID == rf_numParityRegions) {
    767 		/* last region may be larger than other regions */
    768 		regionID--;
    769 	}
    770 	RF_ASSERT(address >= raidPtr->regionInfo[regionID].parityStartAddr);
    771 	RF_ASSERT(address < raidPtr->regionInfo[regionID].parityStartAddr +
    772 		  raidPtr->regionInfo[regionID].numSectorsParity);
    773 	RF_ASSERT(regionID < rf_numParityRegions);
    774 	return (regionID);
    775 }
    776 
    777 
    778 /* given a logical RAID sector, determine physical disk address of data */
    779 void
    780 rf_MapSectorParityLogging(
    781     RF_Raid_t * raidPtr,
    782     RF_RaidAddr_t raidSector,
    783     RF_RowCol_t * col,
    784     RF_SectorNum_t * diskSector,
    785     int remap)
    786 {
    787 	RF_StripeNum_t SUID = raidSector /
    788 		raidPtr->Layout.sectorsPerStripeUnit;
    789 	/* *col = (SUID % (raidPtr->numCol -
    790 	 * raidPtr->Layout.numParityLogCol)); */
    791 	*col = SUID % raidPtr->Layout.numDataCol;
    792 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    793 		raidPtr->Layout.sectorsPerStripeUnit +
    794 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    795 }
    796 
    797 
    798 /* given a logical RAID sector, determine physical disk address of parity  */
    799 void
    800 rf_MapParityParityLogging(
    801     RF_Raid_t * raidPtr,
    802     RF_RaidAddr_t raidSector,
    803     RF_RowCol_t * col,
    804     RF_SectorNum_t * diskSector,
    805     int remap)
    806 {
    807 	RF_StripeNum_t SUID = raidSector /
    808 		raidPtr->Layout.sectorsPerStripeUnit;
    809 
    810 	/* *col =
    811 	 * raidPtr->Layout.numDataCol-(SUID/raidPtr->Layout.numDataCol)%(raidPt
    812 	 * r->numCol - raidPtr->Layout.numParityLogCol); */
    813 	*col = raidPtr->Layout.numDataCol;
    814 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    815 		raidPtr->Layout.sectorsPerStripeUnit +
    816 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    817 }
    818 
    819 
    820 /* given a regionID and sector offset, determine the physical disk address of the parity log */
    821 void
    822 rf_MapLogParityLogging(
    823     RF_Raid_t * raidPtr,
    824     RF_RegionId_t regionID,
    825     RF_SectorNum_t regionOffset,
    826     RF_RowCol_t * col,
    827     RF_SectorNum_t * startSector)
    828 {
    829 	*col = raidPtr->numCol - 1;
    830 	*startSector = raidPtr->regionInfo[regionID].regionStartAddr + regionOffset;
    831 }
    832 
    833 
    834 /* given a regionID, determine the physical disk address of the logged
    835    parity for that region */
    836 void
    837 rf_MapRegionParity(
    838     RF_Raid_t * raidPtr,
    839     RF_RegionId_t regionID,
    840     RF_RowCol_t * col,
    841     RF_SectorNum_t * startSector,
    842     RF_SectorCount_t * numSector)
    843 {
    844 	*col = raidPtr->numCol - 2;
    845 	*startSector = raidPtr->regionInfo[regionID].parityStartAddr;
    846 	*numSector = raidPtr->regionInfo[regionID].numSectorsParity;
    847 }
    848 
    849 
    850 /* given a logical RAID address, determine the participating disks in
    851    the stripe */
    852 void
    853 rf_IdentifyStripeParityLogging(
    854     RF_Raid_t * raidPtr,
    855     RF_RaidAddr_t addr,
    856     RF_RowCol_t ** diskids)
    857 {
    858 	RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout,
    859 							   addr);
    860 	RF_ParityLoggingConfigInfo_t *info = (RF_ParityLoggingConfigInfo_t *)
    861 		raidPtr->Layout.layoutSpecificInfo;
    862 	*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
    863 }
    864 
    865 
    866 void
    867 rf_MapSIDToPSIDParityLogging(
    868     RF_RaidLayout_t * layoutPtr,
    869     RF_StripeNum_t stripeID,
    870     RF_StripeNum_t * psID,
    871     RF_ReconUnitNum_t * which_ru)
    872 {
    873 	*which_ru = 0;
    874 	*psID = stripeID;
    875 }
    876 
    877 
    878 /* select an algorithm for performing an access.  Returns two pointers,
    879  * one to a function that will return information about the DAG, and
    880  * another to a function that will create the dag.
    881  */
    882 void
    883 rf_ParityLoggingDagSelect(
    884     RF_Raid_t * raidPtr,
    885     RF_IoType_t type,
    886     RF_AccessStripeMap_t * asmp,
    887     RF_VoidFuncPtr * createFunc)
    888 {
    889 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
    890 	RF_PhysDiskAddr_t *failedPDA = NULL;
    891 	RF_RowCol_t fcol;
    892 	RF_RowStatus_t rstat;
    893 	int     prior_recon;
    894 
    895 	RF_ASSERT(RF_IO_IS_R_OR_W(type));
    896 
    897 	if (asmp->numDataFailed + asmp->numParityFailed > 1) {
    898 		RF_ERRORMSG("Multiple disks failed in a single group!  Aborting I/O operation.\n");
    899 		*createFunc = NULL;
    900 		return;
    901 	} else
    902 		if (asmp->numDataFailed + asmp->numParityFailed == 1) {
    903 
    904 			/* if under recon & already reconstructed, redirect
    905 			 * the access to the spare drive and eliminate the
    906 			 * failure indication */
    907 			failedPDA = asmp->failedPDAs[0];
    908 			fcol = failedPDA->col;
    909 			rstat = raidPtr->status;
    910 			prior_recon = (rstat == rf_rs_reconfigured) || (
    911 			    (rstat == rf_rs_reconstructing) ?
    912 			    rf_CheckRUReconstructed(raidPtr->reconControl->reconMap, failedPDA->startSector) : 0
    913 			    );
    914 			if (prior_recon) {
    915 				RF_RowCol_t oc = failedPDA->col;
    916 				RF_SectorNum_t oo = failedPDA->startSector;
    917 				if (layoutPtr->map->flags &
    918 				    RF_DISTRIBUTE_SPARE) {
    919 					/* redirect to dist spare space */
    920 
    921 					if (failedPDA == asmp->parityInfo) {
    922 
    923 						/* parity has failed */
    924 						(layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress,
    925 						    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
    926 
    927 						if (asmp->parityInfo->next) {	/* redir 2nd component,
    928 										 * if any */
    929 							RF_PhysDiskAddr_t *p = asmp->parityInfo->next;
    930 							RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit;
    931 							p->col = failedPDA->col;
    932 							p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) +
    933 							    SUoffs;	/* cheating:
    934 									 * startSector is not
    935 									 * really a RAID address */
    936 						}
    937 					} else
    938 						if (asmp->parityInfo->next && failedPDA == asmp->parityInfo->next) {
    939 							RF_ASSERT(0);	/* should not ever
    940 									 * happen */
    941 						} else {
    942 
    943 							/* data has failed */
    944 							(layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress,
    945 							    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
    946 
    947 						}
    948 
    949 				} else {
    950 					/* redirect to dedicated spare space */
    951 
    952 					failedPDA->col = raidPtr->Disks[fcol].spareCol;
    953 
    954 					/* the parity may have two distinct
    955 					 * components, both of which may need
    956 					 * to be redirected */
    957 					if (asmp->parityInfo->next) {
    958 						if (failedPDA == asmp->parityInfo) {
    959 							failedPDA->next->col = failedPDA->col;
    960 						} else
    961 							if (failedPDA == asmp->parityInfo->next) {	/* paranoid:  should never occur */
    962 								asmp->parityInfo->col = failedPDA->col;
    963 							}
    964 					}
    965 				}
    966 
    967 				RF_ASSERT(failedPDA->col != -1);
    968 
    969 				if (rf_dagDebug || rf_mapDebug) {
    970 					printf("raid%d: Redirected type '%c' c %d o %ld -> c %d o %ld\n",
    971 					    raidPtr->raidid, type, oc, (long) oo, failedPDA->col, (long) failedPDA->startSector);
    972 				}
    973 				asmp->numDataFailed = asmp->numParityFailed = 0;
    974 			}
    975 		}
    976 	if (type == RF_IO_TYPE_READ) {
    977 
    978 		if (asmp->numDataFailed == 0)
    979 			*createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG;
    980 		else
    981 			*createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG;
    982 
    983 	} else {
    984 
    985 
    986 		/* if mirroring, always use large writes.  If the access
    987 		 * requires two distinct parity updates, always do a small
    988 		 * write.  If the stripe contains a failure but the access
    989 		 * does not, do a small write. The first conditional
    990 		 * (numStripeUnitsAccessed <= numDataCol/2) uses a
    991 		 * less-than-or-equal rather than just a less-than because
    992 		 * when G is 3 or 4, numDataCol/2 is 1, and I want
    993 		 * single-stripe-unit updates to use just one disk. */
    994 		if ((asmp->numDataFailed + asmp->numParityFailed) == 0) {
    995 			if (((asmp->numStripeUnitsAccessed <=
    996 			      (layoutPtr->numDataCol / 2)) &&
    997 			     (layoutPtr->numDataCol != 1)) ||
    998 			    (asmp->parityInfo->next != NULL) ||
    999 			    rf_CheckStripeForFailures(raidPtr, asmp)) {
   1000 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingSmallWriteDAG;
   1001 			} else
   1002 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingLargeWriteDAG;
   1003 		} else
   1004 			if (asmp->numParityFailed == 1)
   1005 				*createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG;
   1006 			else
   1007 				if (asmp->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit)
   1008 					*createFunc = NULL;
   1009 				else
   1010 					*createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG;
   1011 	}
   1012 }
   1013 #endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
   1014