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rf_paritylogging.c revision 1.15
      1 /*	$NetBSD: rf_paritylogging.c,v 1.15 2003/11/16 20:32:05 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 1.15 2003/11/16 20:32:05 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 	RF_ASSERT(raidPtr->numRow == 1);
    108 
    109 	/* the stripe identifier must identify the disks in each stripe, IN
    110 	 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
    111 	info->stripeIdentifier = rf_make_2d_array((raidPtr->numCol),
    112 						  (raidPtr->numCol),
    113 						  raidPtr->cleanupList);
    114 	if (info->stripeIdentifier == NULL)
    115 		return (ENOMEM);
    116 
    117 	startdisk = 0;
    118 	for (i = 0; i < (raidPtr->numCol); i++) {
    119 		for (j = 0; j < (raidPtr->numCol); j++) {
    120 			info->stripeIdentifier[i][j] = (startdisk + j) %
    121 				(raidPtr->numCol - 1);
    122 		}
    123 		if ((--startdisk) < 0)
    124 			startdisk = raidPtr->numCol - 1 - 1;
    125 	}
    126 
    127 	/* fill in the remaining layout parameters */
    128 	layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
    129 	layoutPtr->numParityCol = 1;
    130 	layoutPtr->numParityLogCol = 1;
    131 	layoutPtr->numDataCol = raidPtr->numCol - layoutPtr->numParityCol -
    132 		layoutPtr->numParityLogCol;
    133 	layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol *
    134 		layoutPtr->sectorsPerStripeUnit;
    135 	layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;
    136 	raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk *
    137 		layoutPtr->sectorsPerStripeUnit;
    138 
    139 	raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk *
    140 		layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
    141 
    142 	/* configure parity log parameters
    143 	 *
    144 	 * parameter               comment/constraints
    145 	 * -------------------------------------------
    146 	 * numParityRegions*       all regions (except possibly last)
    147 	 *                         of equal size
    148 	 * totalInCoreLogCapacity* amount of memory in bytes available
    149 	 *                         for in-core logs (default 1 MB)
    150 	 * numSectorsPerLog#       capacity of an in-core log in sectors
    151 	 *                         (1 * disk track)
    152 	 * numParityLogs           total number of in-core logs,
    153 	 *                         should be at least numParityRegions
    154 	 * regionLogCapacity       size of a region log (except possibly
    155 	 *                         last one) in sectors
    156 	 * totalLogCapacity        total amount of log space in sectors
    157 	 *
    158 	 * where '*' denotes a user settable parameter.
    159 	 * Note that logs are fixed to be the size of a disk track,
    160 	 * value #defined in rf_paritylog.h
    161 	 *
    162 	 */
    163 
    164 	totalLogCapacity = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit * layoutPtr->numParityLogCol;
    165 	raidPtr->regionLogCapacity = totalLogCapacity / rf_numParityRegions;
    166 	if (rf_parityLogDebug)
    167 		printf("bytes per sector %d\n", raidPtr->bytesPerSector);
    168 
    169 	/* reduce fragmentation within a disk region by adjusting the number
    170 	 * of regions in an attempt to allow an integral number of logs to fit
    171 	 * into a disk region */
    172 	fragmentation = raidPtr->regionLogCapacity % raidPtr->numSectorsPerLog;
    173 	if (fragmentation > 0)
    174 		for (i = 1; i < (raidPtr->numSectorsPerLog / 2); i++) {
    175 			if (((totalLogCapacity / (rf_numParityRegions + i)) %
    176 			     raidPtr->numSectorsPerLog) < fragmentation) {
    177 				rf_numParityRegions++;
    178 				raidPtr->regionLogCapacity = totalLogCapacity /
    179 					rf_numParityRegions;
    180 				fragmentation = raidPtr->regionLogCapacity %
    181 					raidPtr->numSectorsPerLog;
    182 			}
    183 			if (((totalLogCapacity / (rf_numParityRegions - i)) %
    184 			     raidPtr->numSectorsPerLog) < fragmentation) {
    185 				rf_numParityRegions--;
    186 				raidPtr->regionLogCapacity = totalLogCapacity /
    187 					rf_numParityRegions;
    188 				fragmentation = raidPtr->regionLogCapacity %
    189 					raidPtr->numSectorsPerLog;
    190 			}
    191 		}
    192 	/* ensure integral number of regions per log */
    193 	raidPtr->regionLogCapacity = (raidPtr->regionLogCapacity /
    194 				      raidPtr->numSectorsPerLog) *
    195 		raidPtr->numSectorsPerLog;
    196 
    197 	raidPtr->numParityLogs = rf_totalInCoreLogCapacity /
    198 		(raidPtr->bytesPerSector * raidPtr->numSectorsPerLog);
    199 	/* to avoid deadlock, must ensure that enough logs exist for each
    200 	 * region to have one simultaneously */
    201 	if (raidPtr->numParityLogs < rf_numParityRegions)
    202 		raidPtr->numParityLogs = rf_numParityRegions;
    203 
    204 	/* create region information structs */
    205 	printf("Allocating %d bytes for in-core parity region info\n",
    206 	       (int) (rf_numParityRegions * sizeof(RF_RegionInfo_t)));
    207 	RF_Malloc(raidPtr->regionInfo,
    208 		  (rf_numParityRegions * sizeof(RF_RegionInfo_t)),
    209 		  (RF_RegionInfo_t *));
    210 	if (raidPtr->regionInfo == NULL)
    211 		return (ENOMEM);
    212 
    213 	/* last region may not be full capacity */
    214 	lastRegionCapacity = raidPtr->regionLogCapacity;
    215 	while ((rf_numParityRegions - 1) * raidPtr->regionLogCapacity +
    216 	       lastRegionCapacity > totalLogCapacity)
    217 		lastRegionCapacity = lastRegionCapacity -
    218 			raidPtr->numSectorsPerLog;
    219 
    220 	raidPtr->regionParityRange = raidPtr->sectorsPerDisk /
    221 		rf_numParityRegions;
    222 	maxRegionParityRange = raidPtr->regionParityRange;
    223 
    224 /* i can't remember why this line is in the code -wvcii 6/30/95 */
    225 /*  if (raidPtr->sectorsPerDisk % rf_numParityRegions > 0)
    226     regionParityRange++; */
    227 
    228 	/* build pool of unused parity logs */
    229 	printf("Allocating %d bytes for %d parity logs\n",
    230 	       raidPtr->numParityLogs * raidPtr->numSectorsPerLog *
    231 	       raidPtr->bytesPerSector,
    232 	       raidPtr->numParityLogs);
    233 	RF_Malloc(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    234 		  raidPtr->numSectorsPerLog * raidPtr->bytesPerSector,
    235 		  (caddr_t));
    236 	if (raidPtr->parityLogBufferHeap == NULL)
    237 		return (ENOMEM);
    238 	lHeapPtr = raidPtr->parityLogBufferHeap;
    239 	rc = rf_mutex_init(&raidPtr->parityLogPool.mutex);
    240 	if (rc) {
    241 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    242 		RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    243 			raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
    244 		return (ENOMEM);
    245 	}
    246 	for (i = 0; i < raidPtr->numParityLogs; i++) {
    247 		if (i == 0) {
    248 			RF_Calloc(raidPtr->parityLogPool.parityLogs, 1,
    249 				  sizeof(RF_ParityLog_t), (RF_ParityLog_t *));
    250 			if (raidPtr->parityLogPool.parityLogs == NULL) {
    251 				RF_Free(raidPtr->parityLogBufferHeap,
    252 					raidPtr->numParityLogs *
    253 					raidPtr->numSectorsPerLog *
    254 					raidPtr->bytesPerSector);
    255 				return (ENOMEM);
    256 			}
    257 			l = raidPtr->parityLogPool.parityLogs;
    258 		} else {
    259 			RF_Calloc(l->next, 1, sizeof(RF_ParityLog_t),
    260 				  (RF_ParityLog_t *));
    261 			if (l->next == NULL) {
    262 				RF_Free(raidPtr->parityLogBufferHeap,
    263 					raidPtr->numParityLogs *
    264 					raidPtr->numSectorsPerLog *
    265 					raidPtr->bytesPerSector);
    266 				for (l = raidPtr->parityLogPool.parityLogs;
    267 				     l;
    268 				     l = next) {
    269 					next = l->next;
    270 					if (l->records)
    271 						RF_Free(l->records, (raidPtr->numSectorsPerLog * sizeof(RF_ParityLogRecord_t)));
    272 					RF_Free(l, sizeof(RF_ParityLog_t));
    273 				}
    274 				return (ENOMEM);
    275 			}
    276 			l = l->next;
    277 		}
    278 		l->bufPtr = lHeapPtr;
    279 		lHeapPtr += raidPtr->numSectorsPerLog *
    280 			raidPtr->bytesPerSector;
    281 		RF_Malloc(l->records, (raidPtr->numSectorsPerLog *
    282 				       sizeof(RF_ParityLogRecord_t)),
    283 			  (RF_ParityLogRecord_t *));
    284 		if (l->records == NULL) {
    285 			RF_Free(raidPtr->parityLogBufferHeap,
    286 				raidPtr->numParityLogs *
    287 				raidPtr->numSectorsPerLog *
    288 				raidPtr->bytesPerSector);
    289 			for (l = raidPtr->parityLogPool.parityLogs;
    290 			     l;
    291 			     l = next) {
    292 				next = l->next;
    293 				if (l->records)
    294 					RF_Free(l->records,
    295 						(raidPtr->numSectorsPerLog *
    296 						 sizeof(RF_ParityLogRecord_t)));
    297 				RF_Free(l, sizeof(RF_ParityLog_t));
    298 			}
    299 			return (ENOMEM);
    300 		}
    301 	}
    302 	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLoggingPool, raidPtr);
    303 	if (rc) {
    304 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    305 		    __LINE__, rc);
    306 		rf_ShutdownParityLoggingPool(raidPtr);
    307 		return (rc);
    308 	}
    309 	/* build pool of region buffers */
    310 	rc = rf_mutex_init(&raidPtr->regionBufferPool.mutex);
    311 	if (rc) {
    312 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    313 		return (ENOMEM);
    314 	}
    315 	rc = rf_cond_init(&raidPtr->regionBufferPool.cond);
    316 	if (rc) {
    317 		rf_print_unable_to_init_cond(__FILE__, __LINE__, rc);
    318 		rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
    319 		return (ENOMEM);
    320 	}
    321 	raidPtr->regionBufferPool.bufferSize = raidPtr->regionLogCapacity *
    322 		raidPtr->bytesPerSector;
    323 	printf("regionBufferPool.bufferSize %d\n",
    324 	       raidPtr->regionBufferPool.bufferSize);
    325 
    326 	/* for now, only one region at a time may be reintegrated */
    327 	raidPtr->regionBufferPool.totalBuffers = 1;
    328 
    329 	raidPtr->regionBufferPool.availableBuffers =
    330 		raidPtr->regionBufferPool.totalBuffers;
    331 	raidPtr->regionBufferPool.availBuffersIndex = 0;
    332 	raidPtr->regionBufferPool.emptyBuffersIndex = 0;
    333 	printf("Allocating %d bytes for regionBufferPool\n",
    334 	       (int) (raidPtr->regionBufferPool.totalBuffers *
    335 		      sizeof(caddr_t)));
    336 	RF_Malloc(raidPtr->regionBufferPool.buffers,
    337 		  raidPtr->regionBufferPool.totalBuffers * sizeof(caddr_t),
    338 		  (caddr_t *));
    339 	if (raidPtr->regionBufferPool.buffers == NULL) {
    340 		rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
    341 		rf_cond_destroy(&raidPtr->regionBufferPool.cond);
    342 		return (ENOMEM);
    343 	}
    344 	for (i = 0; i < raidPtr->regionBufferPool.totalBuffers; i++) {
    345 		printf("Allocating %d bytes for regionBufferPool#%d\n",
    346 		       (int) (raidPtr->regionBufferPool.bufferSize *
    347 			      sizeof(char)), i);
    348 		RF_Malloc(raidPtr->regionBufferPool.buffers[i],
    349 			  raidPtr->regionBufferPool.bufferSize * sizeof(char),
    350 			  (caddr_t));
    351 		if (raidPtr->regionBufferPool.buffers[i] == NULL) {
    352 			rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
    353 			rf_cond_destroy(&raidPtr->regionBufferPool.cond);
    354 			for (j = 0; j < i; j++) {
    355 				RF_Free(raidPtr->regionBufferPool.buffers[i],
    356 					raidPtr->regionBufferPool.bufferSize *
    357 					sizeof(char));
    358 			}
    359 			RF_Free(raidPtr->regionBufferPool.buffers,
    360 				raidPtr->regionBufferPool.totalBuffers *
    361 				sizeof(caddr_t));
    362 			return (ENOMEM);
    363 		}
    364 		printf("raidPtr->regionBufferPool.buffers[%d] = %lx\n", i,
    365 		    (long) raidPtr->regionBufferPool.buffers[i]);
    366 	}
    367 	rc = rf_ShutdownCreate(listp,
    368 			       rf_ShutdownParityLoggingRegionBufferPool,
    369 			       raidPtr);
    370 	if (rc) {
    371 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    372 		    __LINE__, rc);
    373 		rf_ShutdownParityLoggingRegionBufferPool(raidPtr);
    374 		return (rc);
    375 	}
    376 	/* build pool of parity buffers */
    377 	parityBufferCapacity = maxRegionParityRange;
    378 	rc = rf_mutex_init(&raidPtr->parityBufferPool.mutex);
    379 	if (rc) {
    380 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    381 		return (rc);
    382 	}
    383 	rc = rf_cond_init(&raidPtr->parityBufferPool.cond);
    384 	if (rc) {
    385 		rf_print_unable_to_init_cond(__FILE__, __LINE__, rc);
    386 		rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
    387 		return (ENOMEM);
    388 	}
    389 	raidPtr->parityBufferPool.bufferSize = parityBufferCapacity *
    390 		raidPtr->bytesPerSector;
    391 	printf("parityBufferPool.bufferSize %d\n",
    392 	       raidPtr->parityBufferPool.bufferSize);
    393 
    394 	/* for now, only one region at a time may be reintegrated */
    395 	raidPtr->parityBufferPool.totalBuffers = 1;
    396 
    397 	raidPtr->parityBufferPool.availableBuffers =
    398 		raidPtr->parityBufferPool.totalBuffers;
    399 	raidPtr->parityBufferPool.availBuffersIndex = 0;
    400 	raidPtr->parityBufferPool.emptyBuffersIndex = 0;
    401 	printf("Allocating %d bytes for parityBufferPool of %d units\n",
    402 	       (int) (raidPtr->parityBufferPool.totalBuffers *
    403 		      sizeof(caddr_t)),
    404 	       raidPtr->parityBufferPool.totalBuffers );
    405 	RF_Malloc(raidPtr->parityBufferPool.buffers,
    406 		  raidPtr->parityBufferPool.totalBuffers * sizeof(caddr_t),
    407 		  (caddr_t *));
    408 	if (raidPtr->parityBufferPool.buffers == NULL) {
    409 		rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
    410 		rf_cond_destroy(&raidPtr->parityBufferPool.cond);
    411 		return (ENOMEM);
    412 	}
    413 	for (i = 0; i < raidPtr->parityBufferPool.totalBuffers; i++) {
    414 		printf("Allocating %d bytes for parityBufferPool#%d\n",
    415 		       (int) (raidPtr->parityBufferPool.bufferSize *
    416 			      sizeof(char)),i);
    417 		RF_Malloc(raidPtr->parityBufferPool.buffers[i],
    418 			  raidPtr->parityBufferPool.bufferSize * sizeof(char),
    419 			  (caddr_t));
    420 		if (raidPtr->parityBufferPool.buffers == NULL) {
    421 			rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
    422 			rf_cond_destroy(&raidPtr->parityBufferPool.cond);
    423 			for (j = 0; j < i; j++) {
    424 				RF_Free(raidPtr->parityBufferPool.buffers[i],
    425 					raidPtr->regionBufferPool.bufferSize *
    426 					sizeof(char));
    427 			}
    428 			RF_Free(raidPtr->parityBufferPool.buffers,
    429 				raidPtr->regionBufferPool.totalBuffers *
    430 				sizeof(caddr_t));
    431 			return (ENOMEM);
    432 		}
    433 		printf("parityBufferPool.buffers[%d] = %lx\n", i,
    434 		    (long) raidPtr->parityBufferPool.buffers[i]);
    435 	}
    436 	rc = rf_ShutdownCreate(listp,
    437 			       rf_ShutdownParityLoggingParityBufferPool,
    438 			       raidPtr);
    439 	if (rc) {
    440 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    441 		    __LINE__, rc);
    442 		rf_ShutdownParityLoggingParityBufferPool(raidPtr);
    443 		return (rc);
    444 	}
    445 	/* initialize parityLogDiskQueue */
    446 	rc = rf_create_managed_mutex(listp,
    447 				     &raidPtr->parityLogDiskQueue.mutex);
    448 	if (rc) {
    449 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    450 		return (rc);
    451 	}
    452 	rc = rf_create_managed_cond(listp, &raidPtr->parityLogDiskQueue.cond);
    453 	if (rc) {
    454 		rf_print_unable_to_init_cond(__FILE__, __LINE__, rc);
    455 		return (rc);
    456 	}
    457 	raidPtr->parityLogDiskQueue.flushQueue = NULL;
    458 	raidPtr->parityLogDiskQueue.reintQueue = NULL;
    459 	raidPtr->parityLogDiskQueue.bufHead = NULL;
    460 	raidPtr->parityLogDiskQueue.bufTail = NULL;
    461 	raidPtr->parityLogDiskQueue.reintHead = NULL;
    462 	raidPtr->parityLogDiskQueue.reintTail = NULL;
    463 	raidPtr->parityLogDiskQueue.logBlockHead = NULL;
    464 	raidPtr->parityLogDiskQueue.logBlockTail = NULL;
    465 	raidPtr->parityLogDiskQueue.reintBlockHead = NULL;
    466 	raidPtr->parityLogDiskQueue.reintBlockTail = NULL;
    467 	raidPtr->parityLogDiskQueue.freeDataList = NULL;
    468 	raidPtr->parityLogDiskQueue.freeCommonList = NULL;
    469 
    470 	rc = rf_ShutdownCreate(listp,
    471 			       rf_ShutdownParityLoggingDiskQueue,
    472 			       raidPtr);
    473 	if (rc) {
    474 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    475 		    __LINE__, rc);
    476 		return (rc);
    477 	}
    478 	for (i = 0; i < rf_numParityRegions; i++) {
    479 		rc = rf_mutex_init(&raidPtr->regionInfo[i].mutex);
    480 		if (rc) {
    481 			rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    482 			for (j = 0; j < i; j++)
    483 				FreeRegionInfo(raidPtr, j);
    484 			RF_Free(raidPtr->regionInfo,
    485 				(rf_numParityRegions *
    486 				 sizeof(RF_RegionInfo_t)));
    487 			return (ENOMEM);
    488 		}
    489 		rc = rf_mutex_init(&raidPtr->regionInfo[i].reintMutex);
    490 		if (rc) {
    491 			rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    492 			rf_mutex_destroy(&raidPtr->regionInfo[i].mutex);
    493 			for (j = 0; j < i; j++)
    494 				FreeRegionInfo(raidPtr, j);
    495 			RF_Free(raidPtr->regionInfo,
    496 				(rf_numParityRegions *
    497 				 sizeof(RF_RegionInfo_t)));
    498 			return (ENOMEM);
    499 		}
    500 		raidPtr->regionInfo[i].reintInProgress = RF_FALSE;
    501 		raidPtr->regionInfo[i].regionStartAddr =
    502 			raidPtr->regionLogCapacity * i;
    503 		raidPtr->regionInfo[i].parityStartAddr =
    504 			raidPtr->regionParityRange * i;
    505 		if (i < rf_numParityRegions - 1) {
    506 			raidPtr->regionInfo[i].capacity =
    507 				raidPtr->regionLogCapacity;
    508 			raidPtr->regionInfo[i].numSectorsParity =
    509 				raidPtr->regionParityRange;
    510 		} else {
    511 			raidPtr->regionInfo[i].capacity =
    512 				lastRegionCapacity;
    513 			raidPtr->regionInfo[i].numSectorsParity =
    514 				raidPtr->sectorsPerDisk -
    515 				raidPtr->regionParityRange * i;
    516 			if (raidPtr->regionInfo[i].numSectorsParity >
    517 			    maxRegionParityRange)
    518 				maxRegionParityRange =
    519 					raidPtr->regionInfo[i].numSectorsParity;
    520 		}
    521 		raidPtr->regionInfo[i].diskCount = 0;
    522 		RF_ASSERT(raidPtr->regionInfo[i].capacity +
    523 			  raidPtr->regionInfo[i].regionStartAddr <=
    524 			  totalLogCapacity);
    525 		RF_ASSERT(raidPtr->regionInfo[i].parityStartAddr +
    526 			  raidPtr->regionInfo[i].numSectorsParity <=
    527 			  raidPtr->sectorsPerDisk);
    528 		printf("Allocating %d bytes for region %d\n",
    529 		       (int) (raidPtr->regionInfo[i].capacity *
    530 			   sizeof(RF_DiskMap_t)), i);
    531 		RF_Malloc(raidPtr->regionInfo[i].diskMap,
    532 			  (raidPtr->regionInfo[i].capacity *
    533 			   sizeof(RF_DiskMap_t)),
    534 			  (RF_DiskMap_t *));
    535 		if (raidPtr->regionInfo[i].diskMap == NULL) {
    536 			rf_mutex_destroy(&raidPtr->regionInfo[i].mutex);
    537 			rf_mutex_destroy(&raidPtr->regionInfo[i].reintMutex);
    538 			for (j = 0; j < i; j++)
    539 				FreeRegionInfo(raidPtr, j);
    540 			RF_Free(raidPtr->regionInfo,
    541 				(rf_numParityRegions *
    542 				 sizeof(RF_RegionInfo_t)));
    543 			return (ENOMEM);
    544 		}
    545 		raidPtr->regionInfo[i].loggingEnabled = RF_FALSE;
    546 		raidPtr->regionInfo[i].coreLog = NULL;
    547 	}
    548 	rc = rf_ShutdownCreate(listp,
    549 			       rf_ShutdownParityLoggingRegionInfo,
    550 			       raidPtr);
    551 	if (rc) {
    552 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    553 		    __LINE__, rc);
    554 		rf_ShutdownParityLoggingRegionInfo(raidPtr);
    555 		return (rc);
    556 	}
    557 	RF_ASSERT(raidPtr->parityLogDiskQueue.threadState == 0);
    558 	raidPtr->parityLogDiskQueue.threadState = RF_PLOG_CREATED;
    559 	rc = RF_CREATE_THREAD(raidPtr->pLogDiskThreadHandle,
    560 			      rf_ParityLoggingDiskManager, raidPtr,"rf_log");
    561 	if (rc) {
    562 		raidPtr->parityLogDiskQueue.threadState = 0;
    563 		RF_ERRORMSG3("Unable to create parity logging disk thread file %s line %d rc=%d\n",
    564 		    __FILE__, __LINE__, rc);
    565 		return (ENOMEM);
    566 	}
    567 	/* wait for thread to start */
    568 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    569 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_RUNNING)) {
    570 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    571 			     raidPtr->parityLogDiskQueue.mutex);
    572 	}
    573 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    574 
    575 	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLogging, raidPtr);
    576 	if (rc) {
    577 		RF_ERRORMSG1("Got rc=%d adding parity logging shutdown event\n", rc);
    578 		rf_ShutdownParityLogging(raidPtr);
    579 		return (rc);
    580 	}
    581 	if (rf_parityLogDebug) {
    582 		printf("                            size of disk log in sectors: %d\n",
    583 		    (int) totalLogCapacity);
    584 		printf("                            total number of parity regions is %d\n", (int) rf_numParityRegions);
    585 		printf("                            nominal sectors of log per parity region is %d\n", (int) raidPtr->regionLogCapacity);
    586 		printf("                            nominal region fragmentation is %d sectors\n", (int) fragmentation);
    587 		printf("                            total number of parity logs is %d\n", raidPtr->numParityLogs);
    588 		printf("                            parity log size is %d sectors\n", raidPtr->numSectorsPerLog);
    589 		printf("                            total in-core log space is %d bytes\n", (int) rf_totalInCoreLogCapacity);
    590 	}
    591 	rf_EnableParityLogging(raidPtr);
    592 
    593 	return (0);
    594 }
    595 
    596 static void
    597 FreeRegionInfo(
    598     RF_Raid_t * raidPtr,
    599     RF_RegionId_t regionID)
    600 {
    601 	RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    602 	RF_Free(raidPtr->regionInfo[regionID].diskMap,
    603 		(raidPtr->regionInfo[regionID].capacity *
    604 		 sizeof(RF_DiskMap_t)));
    605 	if (!rf_forceParityLogReint && raidPtr->regionInfo[regionID].coreLog) {
    606 		rf_ReleaseParityLogs(raidPtr,
    607 				     raidPtr->regionInfo[regionID].coreLog);
    608 		raidPtr->regionInfo[regionID].coreLog = NULL;
    609 	} else {
    610 		RF_ASSERT(raidPtr->regionInfo[regionID].coreLog == NULL);
    611 		RF_ASSERT(raidPtr->regionInfo[regionID].diskCount == 0);
    612 	}
    613 	RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    614 	rf_mutex_destroy(&raidPtr->regionInfo[regionID].mutex);
    615 	rf_mutex_destroy(&raidPtr->regionInfo[regionID].reintMutex);
    616 }
    617 
    618 
    619 static void
    620 FreeParityLogQueue(
    621     RF_Raid_t * raidPtr,
    622     RF_ParityLogQueue_t * queue)
    623 {
    624 	RF_ParityLog_t *l1, *l2;
    625 
    626 	RF_LOCK_MUTEX(queue->mutex);
    627 	l1 = queue->parityLogs;
    628 	while (l1) {
    629 		l2 = l1;
    630 		l1 = l2->next;
    631 		RF_Free(l2->records, (raidPtr->numSectorsPerLog *
    632 				      sizeof(RF_ParityLogRecord_t)));
    633 		RF_Free(l2, sizeof(RF_ParityLog_t));
    634 	}
    635 	RF_UNLOCK_MUTEX(queue->mutex);
    636 	rf_mutex_destroy(&queue->mutex);
    637 }
    638 
    639 
    640 static void
    641 FreeRegionBufferQueue(RF_RegionBufferQueue_t * queue)
    642 {
    643 	int     i;
    644 
    645 	RF_LOCK_MUTEX(queue->mutex);
    646 	if (queue->availableBuffers != queue->totalBuffers) {
    647 		printf("Attempt to free region queue which is still in use!\n");
    648 		RF_ASSERT(0);
    649 	}
    650 	for (i = 0; i < queue->totalBuffers; i++)
    651 		RF_Free(queue->buffers[i], queue->bufferSize);
    652 	RF_Free(queue->buffers, queue->totalBuffers * sizeof(caddr_t));
    653 	RF_UNLOCK_MUTEX(queue->mutex);
    654 	rf_mutex_destroy(&queue->mutex);
    655 }
    656 
    657 static void
    658 rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg)
    659 {
    660 	RF_Raid_t *raidPtr;
    661 	RF_RegionId_t i;
    662 
    663 	raidPtr = (RF_Raid_t *) arg;
    664 	if (rf_parityLogDebug) {
    665 		printf("raid%d: ShutdownParityLoggingRegionInfo\n",
    666 		       raidPtr->raidid);
    667 	}
    668 	/* free region information structs */
    669 	for (i = 0; i < rf_numParityRegions; i++)
    670 		FreeRegionInfo(raidPtr, i);
    671 	RF_Free(raidPtr->regionInfo, (rf_numParityRegions *
    672 				      sizeof(raidPtr->regionInfo)));
    673 	raidPtr->regionInfo = NULL;
    674 }
    675 
    676 static void
    677 rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg)
    678 {
    679 	RF_Raid_t *raidPtr;
    680 
    681 	raidPtr = (RF_Raid_t *) arg;
    682 	if (rf_parityLogDebug) {
    683 		printf("raid%d: ShutdownParityLoggingPool\n", raidPtr->raidid);
    684 	}
    685 	/* free contents of parityLogPool */
    686 	FreeParityLogQueue(raidPtr, &raidPtr->parityLogPool);
    687 	RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    688 		raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
    689 }
    690 
    691 static void
    692 rf_ShutdownParityLoggingRegionBufferPool(RF_ThreadArg_t arg)
    693 {
    694 	RF_Raid_t *raidPtr;
    695 
    696 	raidPtr = (RF_Raid_t *) arg;
    697 	if (rf_parityLogDebug) {
    698 		printf("raid%d: ShutdownParityLoggingRegionBufferPool\n",
    699 		       raidPtr->raidid);
    700 	}
    701 	FreeRegionBufferQueue(&raidPtr->regionBufferPool);
    702 }
    703 
    704 static void
    705 rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg)
    706 {
    707 	RF_Raid_t *raidPtr;
    708 
    709 	raidPtr = (RF_Raid_t *) arg;
    710 	if (rf_parityLogDebug) {
    711 		printf("raid%d: ShutdownParityLoggingParityBufferPool\n",
    712 		       raidPtr->raidid);
    713 	}
    714 	FreeRegionBufferQueue(&raidPtr->parityBufferPool);
    715 }
    716 
    717 static void
    718 rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg)
    719 {
    720 	RF_ParityLogData_t *d;
    721 	RF_CommonLogData_t *c;
    722 	RF_Raid_t *raidPtr;
    723 
    724 	raidPtr = (RF_Raid_t *) arg;
    725 	if (rf_parityLogDebug) {
    726 		printf("raid%d: ShutdownParityLoggingDiskQueue\n",
    727 		       raidPtr->raidid);
    728 	}
    729 	/* free disk manager stuff */
    730 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufHead == NULL);
    731 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufTail == NULL);
    732 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintHead == NULL);
    733 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintTail == NULL);
    734 	while (raidPtr->parityLogDiskQueue.freeDataList) {
    735 		d = raidPtr->parityLogDiskQueue.freeDataList;
    736 		raidPtr->parityLogDiskQueue.freeDataList =
    737 			raidPtr->parityLogDiskQueue.freeDataList->next;
    738 		RF_Free(d, sizeof(RF_ParityLogData_t));
    739 	}
    740 	while (raidPtr->parityLogDiskQueue.freeCommonList) {
    741 		c = raidPtr->parityLogDiskQueue.freeCommonList;
    742 		rf_mutex_destroy(&c->mutex);
    743 		raidPtr->parityLogDiskQueue.freeCommonList =
    744 			raidPtr->parityLogDiskQueue.freeCommonList->next;
    745 		RF_Free(c, sizeof(RF_CommonLogData_t));
    746 	}
    747 }
    748 
    749 static void
    750 rf_ShutdownParityLogging(RF_ThreadArg_t arg)
    751 {
    752 	RF_Raid_t *raidPtr;
    753 
    754 	raidPtr = (RF_Raid_t *) arg;
    755 	if (rf_parityLogDebug) {
    756 		printf("raid%d: ShutdownParityLogging\n", raidPtr->raidid);
    757 	}
    758 	/* shutdown disk thread */
    759 	/* This has the desirable side-effect of forcing all regions to be
    760 	 * reintegrated.  This is necessary since all parity log maps are
    761 	 * currently held in volatile memory. */
    762 
    763 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    764 	raidPtr->parityLogDiskQueue.threadState |= RF_PLOG_TERMINATE;
    765 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    766 	RF_SIGNAL_COND(raidPtr->parityLogDiskQueue.cond);
    767 	/*
    768          * pLogDiskThread will now terminate when queues are cleared
    769          * now wait for it to be done
    770          */
    771 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    772 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_SHUTDOWN)) {
    773 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    774 			     raidPtr->parityLogDiskQueue.mutex);
    775 	}
    776 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    777 	if (rf_parityLogDebug) {
    778 		printf("raid%d: ShutdownParityLogging done (thread completed)\n", raidPtr->raidid);
    779 	}
    780 }
    781 
    782 int
    783 rf_GetDefaultNumFloatingReconBuffersParityLogging(RF_Raid_t * raidPtr)
    784 {
    785 	return (20);
    786 }
    787 
    788 RF_HeadSepLimit_t
    789 rf_GetDefaultHeadSepLimitParityLogging(RF_Raid_t * raidPtr)
    790 {
    791 	return (10);
    792 }
    793 /* return the region ID for a given RAID address */
    794 RF_RegionId_t
    795 rf_MapRegionIDParityLogging(
    796     RF_Raid_t * raidPtr,
    797     RF_SectorNum_t address)
    798 {
    799 	RF_RegionId_t regionID;
    800 
    801 /*  regionID = address / (raidPtr->regionParityRange * raidPtr->Layout.numDataCol); */
    802 	regionID = address / raidPtr->regionParityRange;
    803 	if (regionID == rf_numParityRegions) {
    804 		/* last region may be larger than other regions */
    805 		regionID--;
    806 	}
    807 	RF_ASSERT(address >= raidPtr->regionInfo[regionID].parityStartAddr);
    808 	RF_ASSERT(address < raidPtr->regionInfo[regionID].parityStartAddr +
    809 		  raidPtr->regionInfo[regionID].numSectorsParity);
    810 	RF_ASSERT(regionID < rf_numParityRegions);
    811 	return (regionID);
    812 }
    813 
    814 
    815 /* given a logical RAID sector, determine physical disk address of data */
    816 void
    817 rf_MapSectorParityLogging(
    818     RF_Raid_t * raidPtr,
    819     RF_RaidAddr_t raidSector,
    820     RF_RowCol_t * row,
    821     RF_RowCol_t * col,
    822     RF_SectorNum_t * diskSector,
    823     int remap)
    824 {
    825 	RF_StripeNum_t SUID = raidSector /
    826 		raidPtr->Layout.sectorsPerStripeUnit;
    827 	*row = 0;
    828 	/* *col = (SUID % (raidPtr->numCol -
    829 	 * raidPtr->Layout.numParityLogCol)); */
    830 	*col = SUID % raidPtr->Layout.numDataCol;
    831 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    832 		raidPtr->Layout.sectorsPerStripeUnit +
    833 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    834 }
    835 
    836 
    837 /* given a logical RAID sector, determine physical disk address of parity  */
    838 void
    839 rf_MapParityParityLogging(
    840     RF_Raid_t * raidPtr,
    841     RF_RaidAddr_t raidSector,
    842     RF_RowCol_t * row,
    843     RF_RowCol_t * col,
    844     RF_SectorNum_t * diskSector,
    845     int remap)
    846 {
    847 	RF_StripeNum_t SUID = raidSector /
    848 		raidPtr->Layout.sectorsPerStripeUnit;
    849 
    850 	*row = 0;
    851 	/* *col =
    852 	 * raidPtr->Layout.numDataCol-(SUID/raidPtr->Layout.numDataCol)%(raidPt
    853 	 * r->numCol - raidPtr->Layout.numParityLogCol); */
    854 	*col = raidPtr->Layout.numDataCol;
    855 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    856 		raidPtr->Layout.sectorsPerStripeUnit +
    857 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    858 }
    859 
    860 
    861 /* given a regionID and sector offset, determine the physical disk address of the parity log */
    862 void
    863 rf_MapLogParityLogging(
    864     RF_Raid_t * raidPtr,
    865     RF_RegionId_t regionID,
    866     RF_SectorNum_t regionOffset,
    867     RF_RowCol_t * row,
    868     RF_RowCol_t * col,
    869     RF_SectorNum_t * startSector)
    870 {
    871 	*row = 0;
    872 	*col = raidPtr->numCol - 1;
    873 	*startSector = raidPtr->regionInfo[regionID].regionStartAddr + regionOffset;
    874 }
    875 
    876 
    877 /* given a regionID, determine the physical disk address of the logged
    878    parity for that region */
    879 void
    880 rf_MapRegionParity(
    881     RF_Raid_t * raidPtr,
    882     RF_RegionId_t regionID,
    883     RF_RowCol_t * row,
    884     RF_RowCol_t * col,
    885     RF_SectorNum_t * startSector,
    886     RF_SectorCount_t * numSector)
    887 {
    888 	*row = 0;
    889 	*col = raidPtr->numCol - 2;
    890 	*startSector = raidPtr->regionInfo[regionID].parityStartAddr;
    891 	*numSector = raidPtr->regionInfo[regionID].numSectorsParity;
    892 }
    893 
    894 
    895 /* given a logical RAID address, determine the participating disks in
    896    the stripe */
    897 void
    898 rf_IdentifyStripeParityLogging(
    899     RF_Raid_t * raidPtr,
    900     RF_RaidAddr_t addr,
    901     RF_RowCol_t ** diskids,
    902     RF_RowCol_t * outRow)
    903 {
    904 	RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout,
    905 							   addr);
    906 	RF_ParityLoggingConfigInfo_t *info = (RF_ParityLoggingConfigInfo_t *)
    907 		raidPtr->Layout.layoutSpecificInfo;
    908 	*outRow = 0;
    909 	*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
    910 }
    911 
    912 
    913 void
    914 rf_MapSIDToPSIDParityLogging(
    915     RF_RaidLayout_t * layoutPtr,
    916     RF_StripeNum_t stripeID,
    917     RF_StripeNum_t * psID,
    918     RF_ReconUnitNum_t * which_ru)
    919 {
    920 	*which_ru = 0;
    921 	*psID = stripeID;
    922 }
    923 
    924 
    925 /* select an algorithm for performing an access.  Returns two pointers,
    926  * one to a function that will return information about the DAG, and
    927  * another to a function that will create the dag.
    928  */
    929 void
    930 rf_ParityLoggingDagSelect(
    931     RF_Raid_t * raidPtr,
    932     RF_IoType_t type,
    933     RF_AccessStripeMap_t * asmp,
    934     RF_VoidFuncPtr * createFunc)
    935 {
    936 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
    937 	RF_PhysDiskAddr_t *failedPDA = NULL;
    938 	RF_RowCol_t frow, fcol;
    939 	RF_RowStatus_t rstat;
    940 	int     prior_recon;
    941 
    942 	RF_ASSERT(RF_IO_IS_R_OR_W(type));
    943 
    944 	if (asmp->numDataFailed + asmp->numParityFailed > 1) {
    945 		RF_ERRORMSG("Multiple disks failed in a single group!  Aborting I/O operation.\n");
    946 		*createFunc = NULL;
    947 		return;
    948 	} else
    949 		if (asmp->numDataFailed + asmp->numParityFailed == 1) {
    950 
    951 			/* if under recon & already reconstructed, redirect
    952 			 * the access to the spare drive and eliminate the
    953 			 * failure indication */
    954 			failedPDA = asmp->failedPDAs[0];
    955 			frow = failedPDA->row;
    956 			fcol = failedPDA->col;
    957 			rstat = raidPtr->status[failedPDA->row];
    958 			prior_recon = (rstat == rf_rs_reconfigured) || (
    959 			    (rstat == rf_rs_reconstructing) ?
    960 			    rf_CheckRUReconstructed(raidPtr->reconControl[frow]->reconMap, failedPDA->startSector) : 0
    961 			    );
    962 			if (prior_recon) {
    963 				RF_RowCol_t or = failedPDA->row, oc = failedPDA->col;
    964 				RF_SectorNum_t oo = failedPDA->startSector;
    965 				if (layoutPtr->map->flags &
    966 				    RF_DISTRIBUTE_SPARE) {
    967 					/* redirect to dist spare space */
    968 
    969 					if (failedPDA == asmp->parityInfo) {
    970 
    971 						/* parity has failed */
    972 						(layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
    973 						    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
    974 
    975 						if (asmp->parityInfo->next) {	/* redir 2nd component,
    976 										 * if any */
    977 							RF_PhysDiskAddr_t *p = asmp->parityInfo->next;
    978 							RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit;
    979 							p->row = failedPDA->row;
    980 							p->col = failedPDA->col;
    981 							p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) +
    982 							    SUoffs;	/* cheating:
    983 									 * startSector is not
    984 									 * really a RAID address */
    985 						}
    986 					} else
    987 						if (asmp->parityInfo->next && failedPDA == asmp->parityInfo->next) {
    988 							RF_ASSERT(0);	/* should not ever
    989 									 * happen */
    990 						} else {
    991 
    992 							/* data has failed */
    993 							(layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
    994 							    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
    995 
    996 						}
    997 
    998 				} else {
    999 					/* redirect to dedicated spare space */
   1000 
   1001 					failedPDA->row = raidPtr->Disks[frow][fcol].spareRow;
   1002 					failedPDA->col = raidPtr->Disks[frow][fcol].spareCol;
   1003 
   1004 					/* the parity may have two distinct
   1005 					 * components, both of which may need
   1006 					 * to be redirected */
   1007 					if (asmp->parityInfo->next) {
   1008 						if (failedPDA == asmp->parityInfo) {
   1009 							failedPDA->next->row = failedPDA->row;
   1010 							failedPDA->next->col = failedPDA->col;
   1011 						} else
   1012 							if (failedPDA == asmp->parityInfo->next) {	/* paranoid:  should never occur */
   1013 								asmp->parityInfo->row = failedPDA->row;
   1014 								asmp->parityInfo->col = failedPDA->col;
   1015 							}
   1016 					}
   1017 				}
   1018 
   1019 				RF_ASSERT(failedPDA->col != -1);
   1020 
   1021 				if (rf_dagDebug || rf_mapDebug) {
   1022 					printf("raid%d: Redirected type '%c' r %d c %d o %ld -> r %d c %d o %ld\n",
   1023 					    raidPtr->raidid, type, or, oc, (long) oo, failedPDA->row, failedPDA->col, (long) failedPDA->startSector);
   1024 				}
   1025 				asmp->numDataFailed = asmp->numParityFailed = 0;
   1026 			}
   1027 		}
   1028 	if (type == RF_IO_TYPE_READ) {
   1029 
   1030 		if (asmp->numDataFailed == 0)
   1031 			*createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG;
   1032 		else
   1033 			*createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG;
   1034 
   1035 	} else {
   1036 
   1037 
   1038 		/* if mirroring, always use large writes.  If the access
   1039 		 * requires two distinct parity updates, always do a small
   1040 		 * write.  If the stripe contains a failure but the access
   1041 		 * does not, do a small write. The first conditional
   1042 		 * (numStripeUnitsAccessed <= numDataCol/2) uses a
   1043 		 * less-than-or-equal rather than just a less-than because
   1044 		 * when G is 3 or 4, numDataCol/2 is 1, and I want
   1045 		 * single-stripe-unit updates to use just one disk. */
   1046 		if ((asmp->numDataFailed + asmp->numParityFailed) == 0) {
   1047 			if (((asmp->numStripeUnitsAccessed <=
   1048 			      (layoutPtr->numDataCol / 2)) &&
   1049 			     (layoutPtr->numDataCol != 1)) ||
   1050 			    (asmp->parityInfo->next != NULL) ||
   1051 			    rf_CheckStripeForFailures(raidPtr, asmp)) {
   1052 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingSmallWriteDAG;
   1053 			} else
   1054 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingLargeWriteDAG;
   1055 		} else
   1056 			if (asmp->numParityFailed == 1)
   1057 				*createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG;
   1058 			else
   1059 				if (asmp->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit)
   1060 					*createFunc = NULL;
   1061 				else
   1062 					*createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG;
   1063 	}
   1064 }
   1065 #endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
   1066