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rf_paritylogging.c revision 1.18
      1 /*	$NetBSD: rf_paritylogging.c,v 1.18 2003/12/29 05:01:14 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 1.18 2003/12/29 05:01:14 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 	rc = rf_cond_init(&raidPtr->regionBufferPool.cond);
    314 	if (rc) {
    315 		rf_print_unable_to_init_cond(__FILE__, __LINE__, rc);
    316 		return (ENOMEM);
    317 	}
    318 	raidPtr->regionBufferPool.bufferSize = raidPtr->regionLogCapacity *
    319 		raidPtr->bytesPerSector;
    320 	printf("regionBufferPool.bufferSize %d\n",
    321 	       raidPtr->regionBufferPool.bufferSize);
    322 
    323 	/* for now, only one region at a time may be reintegrated */
    324 	raidPtr->regionBufferPool.totalBuffers = 1;
    325 
    326 	raidPtr->regionBufferPool.availableBuffers =
    327 		raidPtr->regionBufferPool.totalBuffers;
    328 	raidPtr->regionBufferPool.availBuffersIndex = 0;
    329 	raidPtr->regionBufferPool.emptyBuffersIndex = 0;
    330 	printf("Allocating %d bytes for regionBufferPool\n",
    331 	       (int) (raidPtr->regionBufferPool.totalBuffers *
    332 		      sizeof(caddr_t)));
    333 	RF_Malloc(raidPtr->regionBufferPool.buffers,
    334 		  raidPtr->regionBufferPool.totalBuffers * sizeof(caddr_t),
    335 		  (caddr_t *));
    336 	if (raidPtr->regionBufferPool.buffers == NULL) {
    337 		rf_cond_destroy(&raidPtr->regionBufferPool.cond);
    338 		return (ENOMEM);
    339 	}
    340 	for (i = 0; i < raidPtr->regionBufferPool.totalBuffers; i++) {
    341 		printf("Allocating %d bytes for regionBufferPool#%d\n",
    342 		       (int) (raidPtr->regionBufferPool.bufferSize *
    343 			      sizeof(char)), i);
    344 		RF_Malloc(raidPtr->regionBufferPool.buffers[i],
    345 			  raidPtr->regionBufferPool.bufferSize * sizeof(char),
    346 			  (caddr_t));
    347 		if (raidPtr->regionBufferPool.buffers[i] == NULL) {
    348 			rf_cond_destroy(&raidPtr->regionBufferPool.cond);
    349 			for (j = 0; j < i; j++) {
    350 				RF_Free(raidPtr->regionBufferPool.buffers[i],
    351 					raidPtr->regionBufferPool.bufferSize *
    352 					sizeof(char));
    353 			}
    354 			RF_Free(raidPtr->regionBufferPool.buffers,
    355 				raidPtr->regionBufferPool.totalBuffers *
    356 				sizeof(caddr_t));
    357 			return (ENOMEM);
    358 		}
    359 		printf("raidPtr->regionBufferPool.buffers[%d] = %lx\n", i,
    360 		    (long) raidPtr->regionBufferPool.buffers[i]);
    361 	}
    362 	rc = rf_ShutdownCreate(listp,
    363 			       rf_ShutdownParityLoggingRegionBufferPool,
    364 			       raidPtr);
    365 	if (rc) {
    366 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    367 		    __LINE__, rc);
    368 		rf_ShutdownParityLoggingRegionBufferPool(raidPtr);
    369 		return (rc);
    370 	}
    371 	/* build pool of parity buffers */
    372 	parityBufferCapacity = maxRegionParityRange;
    373 	rc = rf_mutex_init(&raidPtr->parityBufferPool.mutex);
    374 	if (rc) {
    375 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    376 		return (rc);
    377 	}
    378 	rc = rf_cond_init(&raidPtr->parityBufferPool.cond);
    379 	if (rc) {
    380 		rf_print_unable_to_init_cond(__FILE__, __LINE__, rc);
    381 		return (ENOMEM);
    382 	}
    383 	raidPtr->parityBufferPool.bufferSize = parityBufferCapacity *
    384 		raidPtr->bytesPerSector;
    385 	printf("parityBufferPool.bufferSize %d\n",
    386 	       raidPtr->parityBufferPool.bufferSize);
    387 
    388 	/* for now, only one region at a time may be reintegrated */
    389 	raidPtr->parityBufferPool.totalBuffers = 1;
    390 
    391 	raidPtr->parityBufferPool.availableBuffers =
    392 		raidPtr->parityBufferPool.totalBuffers;
    393 	raidPtr->parityBufferPool.availBuffersIndex = 0;
    394 	raidPtr->parityBufferPool.emptyBuffersIndex = 0;
    395 	printf("Allocating %d bytes for parityBufferPool of %d units\n",
    396 	       (int) (raidPtr->parityBufferPool.totalBuffers *
    397 		      sizeof(caddr_t)),
    398 	       raidPtr->parityBufferPool.totalBuffers );
    399 	RF_Malloc(raidPtr->parityBufferPool.buffers,
    400 		  raidPtr->parityBufferPool.totalBuffers * sizeof(caddr_t),
    401 		  (caddr_t *));
    402 	if (raidPtr->parityBufferPool.buffers == NULL) {
    403 		rf_cond_destroy(&raidPtr->parityBufferPool.cond);
    404 		return (ENOMEM);
    405 	}
    406 	for (i = 0; i < raidPtr->parityBufferPool.totalBuffers; i++) {
    407 		printf("Allocating %d bytes for parityBufferPool#%d\n",
    408 		       (int) (raidPtr->parityBufferPool.bufferSize *
    409 			      sizeof(char)),i);
    410 		RF_Malloc(raidPtr->parityBufferPool.buffers[i],
    411 			  raidPtr->parityBufferPool.bufferSize * sizeof(char),
    412 			  (caddr_t));
    413 		if (raidPtr->parityBufferPool.buffers == NULL) {
    414 			rf_cond_destroy(&raidPtr->parityBufferPool.cond);
    415 			for (j = 0; j < i; j++) {
    416 				RF_Free(raidPtr->parityBufferPool.buffers[i],
    417 					raidPtr->regionBufferPool.bufferSize *
    418 					sizeof(char));
    419 			}
    420 			RF_Free(raidPtr->parityBufferPool.buffers,
    421 				raidPtr->regionBufferPool.totalBuffers *
    422 				sizeof(caddr_t));
    423 			return (ENOMEM);
    424 		}
    425 		printf("parityBufferPool.buffers[%d] = %lx\n", i,
    426 		    (long) raidPtr->parityBufferPool.buffers[i]);
    427 	}
    428 	rc = rf_ShutdownCreate(listp,
    429 			       rf_ShutdownParityLoggingParityBufferPool,
    430 			       raidPtr);
    431 	if (rc) {
    432 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    433 		    __LINE__, rc);
    434 		rf_ShutdownParityLoggingParityBufferPool(raidPtr);
    435 		return (rc);
    436 	}
    437 	/* initialize parityLogDiskQueue */
    438 	rc = rf_create_managed_mutex(listp,
    439 				     &raidPtr->parityLogDiskQueue.mutex);
    440 	if (rc) {
    441 		rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    442 		return (rc);
    443 	}
    444 	rc = rf_create_managed_cond(listp, &raidPtr->parityLogDiskQueue.cond);
    445 	if (rc) {
    446 		rf_print_unable_to_init_cond(__FILE__, __LINE__, rc);
    447 		return (rc);
    448 	}
    449 	raidPtr->parityLogDiskQueue.flushQueue = NULL;
    450 	raidPtr->parityLogDiskQueue.reintQueue = NULL;
    451 	raidPtr->parityLogDiskQueue.bufHead = NULL;
    452 	raidPtr->parityLogDiskQueue.bufTail = NULL;
    453 	raidPtr->parityLogDiskQueue.reintHead = NULL;
    454 	raidPtr->parityLogDiskQueue.reintTail = NULL;
    455 	raidPtr->parityLogDiskQueue.logBlockHead = NULL;
    456 	raidPtr->parityLogDiskQueue.logBlockTail = NULL;
    457 	raidPtr->parityLogDiskQueue.reintBlockHead = NULL;
    458 	raidPtr->parityLogDiskQueue.reintBlockTail = NULL;
    459 	raidPtr->parityLogDiskQueue.freeDataList = NULL;
    460 	raidPtr->parityLogDiskQueue.freeCommonList = NULL;
    461 
    462 	rc = rf_ShutdownCreate(listp,
    463 			       rf_ShutdownParityLoggingDiskQueue,
    464 			       raidPtr);
    465 	if (rc) {
    466 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    467 		    __LINE__, rc);
    468 		return (rc);
    469 	}
    470 	for (i = 0; i < rf_numParityRegions; i++) {
    471 		rc = rf_mutex_init(&raidPtr->regionInfo[i].mutex);
    472 		if (rc) {
    473 			rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    474 			for (j = 0; j < i; j++)
    475 				FreeRegionInfo(raidPtr, j);
    476 			RF_Free(raidPtr->regionInfo,
    477 				(rf_numParityRegions *
    478 				 sizeof(RF_RegionInfo_t)));
    479 			return (ENOMEM);
    480 		}
    481 		rc = rf_mutex_init(&raidPtr->regionInfo[i].reintMutex);
    482 		if (rc) {
    483 			rf_print_unable_to_init_mutex(__FILE__, __LINE__, rc);
    484 			for (j = 0; j < i; j++)
    485 				FreeRegionInfo(raidPtr, j);
    486 			RF_Free(raidPtr->regionInfo,
    487 				(rf_numParityRegions *
    488 				 sizeof(RF_RegionInfo_t)));
    489 			return (ENOMEM);
    490 		}
    491 		raidPtr->regionInfo[i].reintInProgress = RF_FALSE;
    492 		raidPtr->regionInfo[i].regionStartAddr =
    493 			raidPtr->regionLogCapacity * i;
    494 		raidPtr->regionInfo[i].parityStartAddr =
    495 			raidPtr->regionParityRange * i;
    496 		if (i < rf_numParityRegions - 1) {
    497 			raidPtr->regionInfo[i].capacity =
    498 				raidPtr->regionLogCapacity;
    499 			raidPtr->regionInfo[i].numSectorsParity =
    500 				raidPtr->regionParityRange;
    501 		} else {
    502 			raidPtr->regionInfo[i].capacity =
    503 				lastRegionCapacity;
    504 			raidPtr->regionInfo[i].numSectorsParity =
    505 				raidPtr->sectorsPerDisk -
    506 				raidPtr->regionParityRange * i;
    507 			if (raidPtr->regionInfo[i].numSectorsParity >
    508 			    maxRegionParityRange)
    509 				maxRegionParityRange =
    510 					raidPtr->regionInfo[i].numSectorsParity;
    511 		}
    512 		raidPtr->regionInfo[i].diskCount = 0;
    513 		RF_ASSERT(raidPtr->regionInfo[i].capacity +
    514 			  raidPtr->regionInfo[i].regionStartAddr <=
    515 			  totalLogCapacity);
    516 		RF_ASSERT(raidPtr->regionInfo[i].parityStartAddr +
    517 			  raidPtr->regionInfo[i].numSectorsParity <=
    518 			  raidPtr->sectorsPerDisk);
    519 		printf("Allocating %d bytes for region %d\n",
    520 		       (int) (raidPtr->regionInfo[i].capacity *
    521 			   sizeof(RF_DiskMap_t)), i);
    522 		RF_Malloc(raidPtr->regionInfo[i].diskMap,
    523 			  (raidPtr->regionInfo[i].capacity *
    524 			   sizeof(RF_DiskMap_t)),
    525 			  (RF_DiskMap_t *));
    526 		if (raidPtr->regionInfo[i].diskMap == NULL) {
    527 			for (j = 0; j < i; j++)
    528 				FreeRegionInfo(raidPtr, j);
    529 			RF_Free(raidPtr->regionInfo,
    530 				(rf_numParityRegions *
    531 				 sizeof(RF_RegionInfo_t)));
    532 			return (ENOMEM);
    533 		}
    534 		raidPtr->regionInfo[i].loggingEnabled = RF_FALSE;
    535 		raidPtr->regionInfo[i].coreLog = NULL;
    536 	}
    537 	rc = rf_ShutdownCreate(listp,
    538 			       rf_ShutdownParityLoggingRegionInfo,
    539 			       raidPtr);
    540 	if (rc) {
    541 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    542 		    __LINE__, rc);
    543 		rf_ShutdownParityLoggingRegionInfo(raidPtr);
    544 		return (rc);
    545 	}
    546 	RF_ASSERT(raidPtr->parityLogDiskQueue.threadState == 0);
    547 	raidPtr->parityLogDiskQueue.threadState = RF_PLOG_CREATED;
    548 	rc = RF_CREATE_THREAD(raidPtr->pLogDiskThreadHandle,
    549 			      rf_ParityLoggingDiskManager, raidPtr,"rf_log");
    550 	if (rc) {
    551 		raidPtr->parityLogDiskQueue.threadState = 0;
    552 		RF_ERRORMSG3("Unable to create parity logging disk thread file %s line %d rc=%d\n",
    553 		    __FILE__, __LINE__, rc);
    554 		return (ENOMEM);
    555 	}
    556 	/* wait for thread to start */
    557 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    558 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_RUNNING)) {
    559 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    560 			     raidPtr->parityLogDiskQueue.mutex);
    561 	}
    562 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    563 
    564 	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLogging, raidPtr);
    565 	if (rc) {
    566 		RF_ERRORMSG1("Got rc=%d adding parity logging shutdown event\n", rc);
    567 		rf_ShutdownParityLogging(raidPtr);
    568 		return (rc);
    569 	}
    570 	if (rf_parityLogDebug) {
    571 		printf("                            size of disk log in sectors: %d\n",
    572 		    (int) totalLogCapacity);
    573 		printf("                            total number of parity regions is %d\n", (int) rf_numParityRegions);
    574 		printf("                            nominal sectors of log per parity region is %d\n", (int) raidPtr->regionLogCapacity);
    575 		printf("                            nominal region fragmentation is %d sectors\n", (int) fragmentation);
    576 		printf("                            total number of parity logs is %d\n", raidPtr->numParityLogs);
    577 		printf("                            parity log size is %d sectors\n", raidPtr->numSectorsPerLog);
    578 		printf("                            total in-core log space is %d bytes\n", (int) rf_totalInCoreLogCapacity);
    579 	}
    580 	rf_EnableParityLogging(raidPtr);
    581 
    582 	return (0);
    583 }
    584 
    585 static void
    586 FreeRegionInfo(
    587     RF_Raid_t * raidPtr,
    588     RF_RegionId_t regionID)
    589 {
    590 	RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    591 	RF_Free(raidPtr->regionInfo[regionID].diskMap,
    592 		(raidPtr->regionInfo[regionID].capacity *
    593 		 sizeof(RF_DiskMap_t)));
    594 	if (!rf_forceParityLogReint && raidPtr->regionInfo[regionID].coreLog) {
    595 		rf_ReleaseParityLogs(raidPtr,
    596 				     raidPtr->regionInfo[regionID].coreLog);
    597 		raidPtr->regionInfo[regionID].coreLog = NULL;
    598 	} else {
    599 		RF_ASSERT(raidPtr->regionInfo[regionID].coreLog == NULL);
    600 		RF_ASSERT(raidPtr->regionInfo[regionID].diskCount == 0);
    601 	}
    602 	RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    603 }
    604 
    605 
    606 static void
    607 FreeParityLogQueue(
    608     RF_Raid_t * raidPtr,
    609     RF_ParityLogQueue_t * queue)
    610 {
    611 	RF_ParityLog_t *l1, *l2;
    612 
    613 	RF_LOCK_MUTEX(queue->mutex);
    614 	l1 = queue->parityLogs;
    615 	while (l1) {
    616 		l2 = l1;
    617 		l1 = l2->next;
    618 		RF_Free(l2->records, (raidPtr->numSectorsPerLog *
    619 				      sizeof(RF_ParityLogRecord_t)));
    620 		RF_Free(l2, sizeof(RF_ParityLog_t));
    621 	}
    622 	RF_UNLOCK_MUTEX(queue->mutex);
    623 }
    624 
    625 
    626 static void
    627 FreeRegionBufferQueue(RF_RegionBufferQueue_t * queue)
    628 {
    629 	int     i;
    630 
    631 	RF_LOCK_MUTEX(queue->mutex);
    632 	if (queue->availableBuffers != queue->totalBuffers) {
    633 		printf("Attempt to free region queue which is still in use!\n");
    634 		RF_ASSERT(0);
    635 	}
    636 	for (i = 0; i < queue->totalBuffers; i++)
    637 		RF_Free(queue->buffers[i], queue->bufferSize);
    638 	RF_Free(queue->buffers, queue->totalBuffers * sizeof(caddr_t));
    639 	RF_UNLOCK_MUTEX(queue->mutex);
    640 }
    641 
    642 static void
    643 rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg)
    644 {
    645 	RF_Raid_t *raidPtr;
    646 	RF_RegionId_t i;
    647 
    648 	raidPtr = (RF_Raid_t *) arg;
    649 	if (rf_parityLogDebug) {
    650 		printf("raid%d: ShutdownParityLoggingRegionInfo\n",
    651 		       raidPtr->raidid);
    652 	}
    653 	/* free region information structs */
    654 	for (i = 0; i < rf_numParityRegions; i++)
    655 		FreeRegionInfo(raidPtr, i);
    656 	RF_Free(raidPtr->regionInfo, (rf_numParityRegions *
    657 				      sizeof(raidPtr->regionInfo)));
    658 	raidPtr->regionInfo = NULL;
    659 }
    660 
    661 static void
    662 rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg)
    663 {
    664 	RF_Raid_t *raidPtr;
    665 
    666 	raidPtr = (RF_Raid_t *) arg;
    667 	if (rf_parityLogDebug) {
    668 		printf("raid%d: ShutdownParityLoggingPool\n", raidPtr->raidid);
    669 	}
    670 	/* free contents of parityLogPool */
    671 	FreeParityLogQueue(raidPtr, &raidPtr->parityLogPool);
    672 	RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    673 		raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
    674 }
    675 
    676 static void
    677 rf_ShutdownParityLoggingRegionBufferPool(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: ShutdownParityLoggingRegionBufferPool\n",
    684 		       raidPtr->raidid);
    685 	}
    686 	FreeRegionBufferQueue(&raidPtr->regionBufferPool);
    687 }
    688 
    689 static void
    690 rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg)
    691 {
    692 	RF_Raid_t *raidPtr;
    693 
    694 	raidPtr = (RF_Raid_t *) arg;
    695 	if (rf_parityLogDebug) {
    696 		printf("raid%d: ShutdownParityLoggingParityBufferPool\n",
    697 		       raidPtr->raidid);
    698 	}
    699 	FreeRegionBufferQueue(&raidPtr->parityBufferPool);
    700 }
    701 
    702 static void
    703 rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg)
    704 {
    705 	RF_ParityLogData_t *d;
    706 	RF_CommonLogData_t *c;
    707 	RF_Raid_t *raidPtr;
    708 
    709 	raidPtr = (RF_Raid_t *) arg;
    710 	if (rf_parityLogDebug) {
    711 		printf("raid%d: ShutdownParityLoggingDiskQueue\n",
    712 		       raidPtr->raidid);
    713 	}
    714 	/* free disk manager stuff */
    715 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufHead == NULL);
    716 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufTail == NULL);
    717 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintHead == NULL);
    718 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintTail == NULL);
    719 	while (raidPtr->parityLogDiskQueue.freeDataList) {
    720 		d = raidPtr->parityLogDiskQueue.freeDataList;
    721 		raidPtr->parityLogDiskQueue.freeDataList =
    722 			raidPtr->parityLogDiskQueue.freeDataList->next;
    723 		RF_Free(d, sizeof(RF_ParityLogData_t));
    724 	}
    725 	while (raidPtr->parityLogDiskQueue.freeCommonList) {
    726 		c = raidPtr->parityLogDiskQueue.freeCommonList;
    727 		raidPtr->parityLogDiskQueue.freeCommonList =
    728 			raidPtr->parityLogDiskQueue.freeCommonList->next;
    729 		RF_Free(c, sizeof(RF_CommonLogData_t));
    730 	}
    731 }
    732 
    733 static void
    734 rf_ShutdownParityLogging(RF_ThreadArg_t arg)
    735 {
    736 	RF_Raid_t *raidPtr;
    737 
    738 	raidPtr = (RF_Raid_t *) arg;
    739 	if (rf_parityLogDebug) {
    740 		printf("raid%d: ShutdownParityLogging\n", raidPtr->raidid);
    741 	}
    742 	/* shutdown disk thread */
    743 	/* This has the desirable side-effect of forcing all regions to be
    744 	 * reintegrated.  This is necessary since all parity log maps are
    745 	 * currently held in volatile memory. */
    746 
    747 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    748 	raidPtr->parityLogDiskQueue.threadState |= RF_PLOG_TERMINATE;
    749 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    750 	RF_SIGNAL_COND(raidPtr->parityLogDiskQueue.cond);
    751 	/*
    752          * pLogDiskThread will now terminate when queues are cleared
    753          * now wait for it to be done
    754          */
    755 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    756 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_SHUTDOWN)) {
    757 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    758 			     raidPtr->parityLogDiskQueue.mutex);
    759 	}
    760 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    761 	if (rf_parityLogDebug) {
    762 		printf("raid%d: ShutdownParityLogging done (thread completed)\n", raidPtr->raidid);
    763 	}
    764 }
    765 
    766 int
    767 rf_GetDefaultNumFloatingReconBuffersParityLogging(RF_Raid_t * raidPtr)
    768 {
    769 	return (20);
    770 }
    771 
    772 RF_HeadSepLimit_t
    773 rf_GetDefaultHeadSepLimitParityLogging(RF_Raid_t * raidPtr)
    774 {
    775 	return (10);
    776 }
    777 /* return the region ID for a given RAID address */
    778 RF_RegionId_t
    779 rf_MapRegionIDParityLogging(
    780     RF_Raid_t * raidPtr,
    781     RF_SectorNum_t address)
    782 {
    783 	RF_RegionId_t regionID;
    784 
    785 /*  regionID = address / (raidPtr->regionParityRange * raidPtr->Layout.numDataCol); */
    786 	regionID = address / raidPtr->regionParityRange;
    787 	if (regionID == rf_numParityRegions) {
    788 		/* last region may be larger than other regions */
    789 		regionID--;
    790 	}
    791 	RF_ASSERT(address >= raidPtr->regionInfo[regionID].parityStartAddr);
    792 	RF_ASSERT(address < raidPtr->regionInfo[regionID].parityStartAddr +
    793 		  raidPtr->regionInfo[regionID].numSectorsParity);
    794 	RF_ASSERT(regionID < rf_numParityRegions);
    795 	return (regionID);
    796 }
    797 
    798 
    799 /* given a logical RAID sector, determine physical disk address of data */
    800 void
    801 rf_MapSectorParityLogging(
    802     RF_Raid_t * raidPtr,
    803     RF_RaidAddr_t raidSector,
    804     RF_RowCol_t * col,
    805     RF_SectorNum_t * diskSector,
    806     int remap)
    807 {
    808 	RF_StripeNum_t SUID = raidSector /
    809 		raidPtr->Layout.sectorsPerStripeUnit;
    810 	/* *col = (SUID % (raidPtr->numCol -
    811 	 * raidPtr->Layout.numParityLogCol)); */
    812 	*col = SUID % raidPtr->Layout.numDataCol;
    813 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    814 		raidPtr->Layout.sectorsPerStripeUnit +
    815 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    816 }
    817 
    818 
    819 /* given a logical RAID sector, determine physical disk address of parity  */
    820 void
    821 rf_MapParityParityLogging(
    822     RF_Raid_t * raidPtr,
    823     RF_RaidAddr_t raidSector,
    824     RF_RowCol_t * col,
    825     RF_SectorNum_t * diskSector,
    826     int remap)
    827 {
    828 	RF_StripeNum_t SUID = raidSector /
    829 		raidPtr->Layout.sectorsPerStripeUnit;
    830 
    831 	/* *col =
    832 	 * raidPtr->Layout.numDataCol-(SUID/raidPtr->Layout.numDataCol)%(raidPt
    833 	 * r->numCol - raidPtr->Layout.numParityLogCol); */
    834 	*col = raidPtr->Layout.numDataCol;
    835 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    836 		raidPtr->Layout.sectorsPerStripeUnit +
    837 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    838 }
    839 
    840 
    841 /* given a regionID and sector offset, determine the physical disk address of the parity log */
    842 void
    843 rf_MapLogParityLogging(
    844     RF_Raid_t * raidPtr,
    845     RF_RegionId_t regionID,
    846     RF_SectorNum_t regionOffset,
    847     RF_RowCol_t * col,
    848     RF_SectorNum_t * startSector)
    849 {
    850 	*col = raidPtr->numCol - 1;
    851 	*startSector = raidPtr->regionInfo[regionID].regionStartAddr + regionOffset;
    852 }
    853 
    854 
    855 /* given a regionID, determine the physical disk address of the logged
    856    parity for that region */
    857 void
    858 rf_MapRegionParity(
    859     RF_Raid_t * raidPtr,
    860     RF_RegionId_t regionID,
    861     RF_RowCol_t * col,
    862     RF_SectorNum_t * startSector,
    863     RF_SectorCount_t * numSector)
    864 {
    865 	*col = raidPtr->numCol - 2;
    866 	*startSector = raidPtr->regionInfo[regionID].parityStartAddr;
    867 	*numSector = raidPtr->regionInfo[regionID].numSectorsParity;
    868 }
    869 
    870 
    871 /* given a logical RAID address, determine the participating disks in
    872    the stripe */
    873 void
    874 rf_IdentifyStripeParityLogging(
    875     RF_Raid_t * raidPtr,
    876     RF_RaidAddr_t addr,
    877     RF_RowCol_t ** diskids)
    878 {
    879 	RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout,
    880 							   addr);
    881 	RF_ParityLoggingConfigInfo_t *info = (RF_ParityLoggingConfigInfo_t *)
    882 		raidPtr->Layout.layoutSpecificInfo;
    883 	*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
    884 }
    885 
    886 
    887 void
    888 rf_MapSIDToPSIDParityLogging(
    889     RF_RaidLayout_t * layoutPtr,
    890     RF_StripeNum_t stripeID,
    891     RF_StripeNum_t * psID,
    892     RF_ReconUnitNum_t * which_ru)
    893 {
    894 	*which_ru = 0;
    895 	*psID = stripeID;
    896 }
    897 
    898 
    899 /* select an algorithm for performing an access.  Returns two pointers,
    900  * one to a function that will return information about the DAG, and
    901  * another to a function that will create the dag.
    902  */
    903 void
    904 rf_ParityLoggingDagSelect(
    905     RF_Raid_t * raidPtr,
    906     RF_IoType_t type,
    907     RF_AccessStripeMap_t * asmp,
    908     RF_VoidFuncPtr * createFunc)
    909 {
    910 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
    911 	RF_PhysDiskAddr_t *failedPDA = NULL;
    912 	RF_RowCol_t fcol;
    913 	RF_RowStatus_t rstat;
    914 	int     prior_recon;
    915 
    916 	RF_ASSERT(RF_IO_IS_R_OR_W(type));
    917 
    918 	if (asmp->numDataFailed + asmp->numParityFailed > 1) {
    919 		RF_ERRORMSG("Multiple disks failed in a single group!  Aborting I/O operation.\n");
    920 		*createFunc = NULL;
    921 		return;
    922 	} else
    923 		if (asmp->numDataFailed + asmp->numParityFailed == 1) {
    924 
    925 			/* if under recon & already reconstructed, redirect
    926 			 * the access to the spare drive and eliminate the
    927 			 * failure indication */
    928 			failedPDA = asmp->failedPDAs[0];
    929 			fcol = failedPDA->col;
    930 			rstat = raidPtr->status;
    931 			prior_recon = (rstat == rf_rs_reconfigured) || (
    932 			    (rstat == rf_rs_reconstructing) ?
    933 			    rf_CheckRUReconstructed(raidPtr->reconControl->reconMap, failedPDA->startSector) : 0
    934 			    );
    935 			if (prior_recon) {
    936 				RF_RowCol_t oc = failedPDA->col;
    937 				RF_SectorNum_t oo = failedPDA->startSector;
    938 				if (layoutPtr->map->flags &
    939 				    RF_DISTRIBUTE_SPARE) {
    940 					/* redirect to dist spare space */
    941 
    942 					if (failedPDA == asmp->parityInfo) {
    943 
    944 						/* parity has failed */
    945 						(layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress,
    946 						    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
    947 
    948 						if (asmp->parityInfo->next) {	/* redir 2nd component,
    949 										 * if any */
    950 							RF_PhysDiskAddr_t *p = asmp->parityInfo->next;
    951 							RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit;
    952 							p->col = failedPDA->col;
    953 							p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) +
    954 							    SUoffs;	/* cheating:
    955 									 * startSector is not
    956 									 * really a RAID address */
    957 						}
    958 					} else
    959 						if (asmp->parityInfo->next && failedPDA == asmp->parityInfo->next) {
    960 							RF_ASSERT(0);	/* should not ever
    961 									 * happen */
    962 						} else {
    963 
    964 							/* data has failed */
    965 							(layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress,
    966 							    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
    967 
    968 						}
    969 
    970 				} else {
    971 					/* redirect to dedicated spare space */
    972 
    973 					failedPDA->col = raidPtr->Disks[fcol].spareCol;
    974 
    975 					/* the parity may have two distinct
    976 					 * components, both of which may need
    977 					 * to be redirected */
    978 					if (asmp->parityInfo->next) {
    979 						if (failedPDA == asmp->parityInfo) {
    980 							failedPDA->next->col = failedPDA->col;
    981 						} else
    982 							if (failedPDA == asmp->parityInfo->next) {	/* paranoid:  should never occur */
    983 								asmp->parityInfo->col = failedPDA->col;
    984 							}
    985 					}
    986 				}
    987 
    988 				RF_ASSERT(failedPDA->col != -1);
    989 
    990 				if (rf_dagDebug || rf_mapDebug) {
    991 					printf("raid%d: Redirected type '%c' c %d o %ld -> c %d o %ld\n",
    992 					    raidPtr->raidid, type, oc, (long) oo, failedPDA->col, (long) failedPDA->startSector);
    993 				}
    994 				asmp->numDataFailed = asmp->numParityFailed = 0;
    995 			}
    996 		}
    997 	if (type == RF_IO_TYPE_READ) {
    998 
    999 		if (asmp->numDataFailed == 0)
   1000 			*createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG;
   1001 		else
   1002 			*createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG;
   1003 
   1004 	} else {
   1005 
   1006 
   1007 		/* if mirroring, always use large writes.  If the access
   1008 		 * requires two distinct parity updates, always do a small
   1009 		 * write.  If the stripe contains a failure but the access
   1010 		 * does not, do a small write. The first conditional
   1011 		 * (numStripeUnitsAccessed <= numDataCol/2) uses a
   1012 		 * less-than-or-equal rather than just a less-than because
   1013 		 * when G is 3 or 4, numDataCol/2 is 1, and I want
   1014 		 * single-stripe-unit updates to use just one disk. */
   1015 		if ((asmp->numDataFailed + asmp->numParityFailed) == 0) {
   1016 			if (((asmp->numStripeUnitsAccessed <=
   1017 			      (layoutPtr->numDataCol / 2)) &&
   1018 			     (layoutPtr->numDataCol != 1)) ||
   1019 			    (asmp->parityInfo->next != NULL) ||
   1020 			    rf_CheckStripeForFailures(raidPtr, asmp)) {
   1021 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingSmallWriteDAG;
   1022 			} else
   1023 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingLargeWriteDAG;
   1024 		} else
   1025 			if (asmp->numParityFailed == 1)
   1026 				*createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG;
   1027 			else
   1028 				if (asmp->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit)
   1029 					*createFunc = NULL;
   1030 				else
   1031 					*createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG;
   1032 	}
   1033 }
   1034 #endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
   1035