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rf_paritylogging.c revision 1.10
      1 /*	$NetBSD: rf_paritylogging.c,v 1.10 2000/02/12 16:06:27 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 "rf_archs.h"
     35 
     36 #if RF_INCLUDE_PARITYLOGGING > 0
     37 
     38 #include "rf_types.h"
     39 #include "rf_raid.h"
     40 #include "rf_dag.h"
     41 #include "rf_dagutils.h"
     42 #include "rf_dagfuncs.h"
     43 #include "rf_dagffrd.h"
     44 #include "rf_dagffwr.h"
     45 #include "rf_dagdegrd.h"
     46 #include "rf_dagdegwr.h"
     47 #include "rf_paritylog.h"
     48 #include "rf_paritylogDiskMgr.h"
     49 #include "rf_paritylogging.h"
     50 #include "rf_parityloggingdags.h"
     51 #include "rf_general.h"
     52 #include "rf_map.h"
     53 #include "rf_utils.h"
     54 #include "rf_shutdown.h"
     55 
     56 typedef struct RF_ParityLoggingConfigInfo_s {
     57 	RF_RowCol_t **stripeIdentifier;	/* filled in at config time & used by
     58 					 * IdentifyStripe */
     59 }       RF_ParityLoggingConfigInfo_t;
     60 
     61 static void FreeRegionInfo(RF_Raid_t * raidPtr, RF_RegionId_t regionID);
     62 static void rf_ShutdownParityLogging(RF_ThreadArg_t arg);
     63 static void rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg);
     64 static void rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg);
     65 static void rf_ShutdownParityLoggingRegionBufferPool(RF_ThreadArg_t arg);
     66 static void rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg);
     67 static void rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg);
     68 
     69 int
     70 rf_ConfigureParityLogging(
     71     RF_ShutdownList_t ** listp,
     72     RF_Raid_t * raidPtr,
     73     RF_Config_t * cfgPtr)
     74 {
     75 	int     i, j, startdisk, rc;
     76 	RF_SectorCount_t totalLogCapacity, fragmentation, lastRegionCapacity;
     77 	RF_SectorCount_t parityBufferCapacity, maxRegionParityRange;
     78 	RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
     79 	RF_ParityLoggingConfigInfo_t *info;
     80 	RF_ParityLog_t *l = NULL, *next;
     81 	caddr_t lHeapPtr;
     82 
     83 	if (rf_numParityRegions <= 0)
     84 		return(EINVAL);
     85 
     86 	/*
     87          * We create multiple entries on the shutdown list here, since
     88          * this configuration routine is fairly complicated in and of
     89          * itself, and this makes backing out of a failed configuration
     90          * much simpler.
     91          */
     92 
     93 	raidPtr->numSectorsPerLog = RF_DEFAULT_NUM_SECTORS_PER_LOG;
     94 
     95 	/* create a parity logging configuration structure */
     96 	RF_MallocAndAdd(info, sizeof(RF_ParityLoggingConfigInfo_t),
     97 			(RF_ParityLoggingConfigInfo_t *),
     98 			raidPtr->cleanupList);
     99 	if (info == NULL)
    100 		return (ENOMEM);
    101 	layoutPtr->layoutSpecificInfo = (void *) info;
    102 
    103 	RF_ASSERT(raidPtr->numRow == 1);
    104 
    105 	/* the stripe identifier must identify the disks in each stripe, IN
    106 	 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
    107 	info->stripeIdentifier = rf_make_2d_array((raidPtr->numCol),
    108 						  (raidPtr->numCol),
    109 						  raidPtr->cleanupList);
    110 	if (info->stripeIdentifier == NULL)
    111 		return (ENOMEM);
    112 
    113 	startdisk = 0;
    114 	for (i = 0; i < (raidPtr->numCol); i++) {
    115 		for (j = 0; j < (raidPtr->numCol); j++) {
    116 			info->stripeIdentifier[i][j] = (startdisk + j) %
    117 				(raidPtr->numCol - 1);
    118 		}
    119 		if ((--startdisk) < 0)
    120 			startdisk = raidPtr->numCol - 1 - 1;
    121 	}
    122 
    123 	/* fill in the remaining layout parameters */
    124 	layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
    125 	layoutPtr->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit <<
    126 		raidPtr->logBytesPerSector;
    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_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n",
    240 			     __FILE__, __LINE__, rc);
    241 		RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    242 			raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
    243 		return (ENOMEM);
    244 	}
    245 	for (i = 0; i < raidPtr->numParityLogs; i++) {
    246 		if (i == 0) {
    247 			RF_Calloc(raidPtr->parityLogPool.parityLogs, 1,
    248 				  sizeof(RF_ParityLog_t), (RF_ParityLog_t *));
    249 			if (raidPtr->parityLogPool.parityLogs == NULL) {
    250 				RF_Free(raidPtr->parityLogBufferHeap,
    251 					raidPtr->numParityLogs *
    252 					raidPtr->numSectorsPerLog *
    253 					raidPtr->bytesPerSector);
    254 				return (ENOMEM);
    255 			}
    256 			l = raidPtr->parityLogPool.parityLogs;
    257 		} else {
    258 			RF_Calloc(l->next, 1, sizeof(RF_ParityLog_t),
    259 				  (RF_ParityLog_t *));
    260 			if (l->next == NULL) {
    261 				RF_Free(raidPtr->parityLogBufferHeap,
    262 					raidPtr->numParityLogs *
    263 					raidPtr->numSectorsPerLog *
    264 					raidPtr->bytesPerSector);
    265 				for (l = raidPtr->parityLogPool.parityLogs;
    266 				     l;
    267 				     l = next) {
    268 					next = l->next;
    269 					if (l->records)
    270 						RF_Free(l->records, (raidPtr->numSectorsPerLog * sizeof(RF_ParityLogRecord_t)));
    271 					RF_Free(l, sizeof(RF_ParityLog_t));
    272 				}
    273 				return (ENOMEM);
    274 			}
    275 			l = l->next;
    276 		}
    277 		l->bufPtr = lHeapPtr;
    278 		lHeapPtr += raidPtr->numSectorsPerLog *
    279 			raidPtr->bytesPerSector;
    280 		RF_Malloc(l->records, (raidPtr->numSectorsPerLog *
    281 				       sizeof(RF_ParityLogRecord_t)),
    282 			  (RF_ParityLogRecord_t *));
    283 		if (l->records == NULL) {
    284 			RF_Free(raidPtr->parityLogBufferHeap,
    285 				raidPtr->numParityLogs *
    286 				raidPtr->numSectorsPerLog *
    287 				raidPtr->bytesPerSector);
    288 			for (l = raidPtr->parityLogPool.parityLogs;
    289 			     l;
    290 			     l = next) {
    291 				next = l->next;
    292 				if (l->records)
    293 					RF_Free(l->records,
    294 						(raidPtr->numSectorsPerLog *
    295 						 sizeof(RF_ParityLogRecord_t)));
    296 				RF_Free(l, sizeof(RF_ParityLog_t));
    297 			}
    298 			return (ENOMEM);
    299 		}
    300 	}
    301 	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLoggingPool, raidPtr);
    302 	if (rc) {
    303 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    304 		    __LINE__, rc);
    305 		rf_ShutdownParityLoggingPool(raidPtr);
    306 		return (rc);
    307 	}
    308 	/* build pool of region buffers */
    309 	rc = rf_mutex_init(&raidPtr->regionBufferPool.mutex);
    310 	if (rc) {
    311 		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n",
    312 			     __FILE__, __LINE__, rc);
    313 		return (ENOMEM);
    314 	}
    315 	rc = rf_cond_init(&raidPtr->regionBufferPool.cond);
    316 	if (rc) {
    317 		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n",
    318 			     __FILE__, __LINE__, rc);
    319 		rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
    320 		return (ENOMEM);
    321 	}
    322 	raidPtr->regionBufferPool.bufferSize = raidPtr->regionLogCapacity *
    323 		raidPtr->bytesPerSector;
    324 	printf("regionBufferPool.bufferSize %d\n",
    325 	       raidPtr->regionBufferPool.bufferSize);
    326 
    327 	/* for now, only one region at a time may be reintegrated */
    328 	raidPtr->regionBufferPool.totalBuffers = 1;
    329 
    330 	raidPtr->regionBufferPool.availableBuffers =
    331 		raidPtr->regionBufferPool.totalBuffers;
    332 	raidPtr->regionBufferPool.availBuffersIndex = 0;
    333 	raidPtr->regionBufferPool.emptyBuffersIndex = 0;
    334 	printf("Allocating %d bytes for regionBufferPool\n",
    335 	       (int) (raidPtr->regionBufferPool.totalBuffers *
    336 		      sizeof(caddr_t)));
    337 	RF_Malloc(raidPtr->regionBufferPool.buffers,
    338 		  raidPtr->regionBufferPool.totalBuffers * sizeof(caddr_t),
    339 		  (caddr_t *));
    340 	if (raidPtr->regionBufferPool.buffers == NULL) {
    341 		rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
    342 		rf_cond_destroy(&raidPtr->regionBufferPool.cond);
    343 		return (ENOMEM);
    344 	}
    345 	for (i = 0; i < raidPtr->regionBufferPool.totalBuffers; i++) {
    346 		printf("Allocating %d bytes for regionBufferPool#%d\n",
    347 		       (int) (raidPtr->regionBufferPool.bufferSize *
    348 			      sizeof(char)), i);
    349 		RF_Malloc(raidPtr->regionBufferPool.buffers[i],
    350 			  raidPtr->regionBufferPool.bufferSize * sizeof(char),
    351 			  (caddr_t));
    352 		if (raidPtr->regionBufferPool.buffers[i] == NULL) {
    353 			rf_mutex_destroy(&raidPtr->regionBufferPool.mutex);
    354 			rf_cond_destroy(&raidPtr->regionBufferPool.cond);
    355 			for (j = 0; j < i; j++) {
    356 				RF_Free(raidPtr->regionBufferPool.buffers[i],
    357 					raidPtr->regionBufferPool.bufferSize *
    358 					sizeof(char));
    359 			}
    360 			RF_Free(raidPtr->regionBufferPool.buffers,
    361 				raidPtr->regionBufferPool.totalBuffers *
    362 				sizeof(caddr_t));
    363 			return (ENOMEM);
    364 		}
    365 		printf("raidPtr->regionBufferPool.buffers[%d] = %lx\n", i,
    366 		    (long) raidPtr->regionBufferPool.buffers[i]);
    367 	}
    368 	rc = rf_ShutdownCreate(listp,
    369 			       rf_ShutdownParityLoggingRegionBufferPool,
    370 			       raidPtr);
    371 	if (rc) {
    372 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    373 		    __LINE__, rc);
    374 		rf_ShutdownParityLoggingRegionBufferPool(raidPtr);
    375 		return (rc);
    376 	}
    377 	/* build pool of parity buffers */
    378 	parityBufferCapacity = maxRegionParityRange;
    379 	rc = rf_mutex_init(&raidPtr->parityBufferPool.mutex);
    380 	if (rc) {
    381 		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n",
    382 			     __FILE__, __LINE__, rc);
    383 		return (rc);
    384 	}
    385 	rc = rf_cond_init(&raidPtr->parityBufferPool.cond);
    386 	if (rc) {
    387 		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n",
    388 			     __FILE__, __LINE__, rc);
    389 		rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
    390 		return (ENOMEM);
    391 	}
    392 	raidPtr->parityBufferPool.bufferSize = parityBufferCapacity *
    393 		raidPtr->bytesPerSector;
    394 	printf("parityBufferPool.bufferSize %d\n",
    395 	       raidPtr->parityBufferPool.bufferSize);
    396 
    397 	/* for now, only one region at a time may be reintegrated */
    398 	raidPtr->parityBufferPool.totalBuffers = 1;
    399 
    400 	raidPtr->parityBufferPool.availableBuffers =
    401 		raidPtr->parityBufferPool.totalBuffers;
    402 	raidPtr->parityBufferPool.availBuffersIndex = 0;
    403 	raidPtr->parityBufferPool.emptyBuffersIndex = 0;
    404 	printf("Allocating %d bytes for parityBufferPool of %d units\n",
    405 	       (int) (raidPtr->parityBufferPool.totalBuffers *
    406 		      sizeof(caddr_t)),
    407 	       raidPtr->parityBufferPool.totalBuffers );
    408 	RF_Malloc(raidPtr->parityBufferPool.buffers,
    409 		  raidPtr->parityBufferPool.totalBuffers * sizeof(caddr_t),
    410 		  (caddr_t *));
    411 	if (raidPtr->parityBufferPool.buffers == NULL) {
    412 		rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
    413 		rf_cond_destroy(&raidPtr->parityBufferPool.cond);
    414 		return (ENOMEM);
    415 	}
    416 	for (i = 0; i < raidPtr->parityBufferPool.totalBuffers; i++) {
    417 		printf("Allocating %d bytes for parityBufferPool#%d\n",
    418 		       (int) (raidPtr->parityBufferPool.bufferSize *
    419 			      sizeof(char)),i);
    420 		RF_Malloc(raidPtr->parityBufferPool.buffers[i],
    421 			  raidPtr->parityBufferPool.bufferSize * sizeof(char),
    422 			  (caddr_t));
    423 		if (raidPtr->parityBufferPool.buffers == NULL) {
    424 			rf_mutex_destroy(&raidPtr->parityBufferPool.mutex);
    425 			rf_cond_destroy(&raidPtr->parityBufferPool.cond);
    426 			for (j = 0; j < i; j++) {
    427 				RF_Free(raidPtr->parityBufferPool.buffers[i],
    428 					raidPtr->regionBufferPool.bufferSize *
    429 					sizeof(char));
    430 			}
    431 			RF_Free(raidPtr->parityBufferPool.buffers,
    432 				raidPtr->regionBufferPool.totalBuffers *
    433 				sizeof(caddr_t));
    434 			return (ENOMEM);
    435 		}
    436 		printf("parityBufferPool.buffers[%d] = %lx\n", i,
    437 		    (long) raidPtr->parityBufferPool.buffers[i]);
    438 	}
    439 	rc = rf_ShutdownCreate(listp,
    440 			       rf_ShutdownParityLoggingParityBufferPool,
    441 			       raidPtr);
    442 	if (rc) {
    443 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    444 		    __LINE__, rc);
    445 		rf_ShutdownParityLoggingParityBufferPool(raidPtr);
    446 		return (rc);
    447 	}
    448 	/* initialize parityLogDiskQueue */
    449 	rc = rf_create_managed_mutex(listp,
    450 				     &raidPtr->parityLogDiskQueue.mutex);
    451 	if (rc) {
    452 		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n",
    453 			     __FILE__, __LINE__, rc);
    454 		return (rc);
    455 	}
    456 	rc = rf_create_managed_cond(listp, &raidPtr->parityLogDiskQueue.cond);
    457 	if (rc) {
    458 		RF_ERRORMSG3("Unable to init cond file %s line %d rc=%d\n",
    459 			     __FILE__, __LINE__, rc);
    460 		return (rc);
    461 	}
    462 	raidPtr->parityLogDiskQueue.flushQueue = NULL;
    463 	raidPtr->parityLogDiskQueue.reintQueue = NULL;
    464 	raidPtr->parityLogDiskQueue.bufHead = NULL;
    465 	raidPtr->parityLogDiskQueue.bufTail = NULL;
    466 	raidPtr->parityLogDiskQueue.reintHead = NULL;
    467 	raidPtr->parityLogDiskQueue.reintTail = NULL;
    468 	raidPtr->parityLogDiskQueue.logBlockHead = NULL;
    469 	raidPtr->parityLogDiskQueue.logBlockTail = NULL;
    470 	raidPtr->parityLogDiskQueue.reintBlockHead = NULL;
    471 	raidPtr->parityLogDiskQueue.reintBlockTail = NULL;
    472 	raidPtr->parityLogDiskQueue.freeDataList = NULL;
    473 	raidPtr->parityLogDiskQueue.freeCommonList = NULL;
    474 
    475 	rc = rf_ShutdownCreate(listp,
    476 			       rf_ShutdownParityLoggingDiskQueue,
    477 			       raidPtr);
    478 	if (rc) {
    479 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    480 		    __LINE__, rc);
    481 		return (rc);
    482 	}
    483 	for (i = 0; i < rf_numParityRegions; i++) {
    484 		rc = rf_mutex_init(&raidPtr->regionInfo[i].mutex);
    485 		if (rc) {
    486 			RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", __FILE__,
    487 			    __LINE__, rc);
    488 			for (j = 0; j < i; j++)
    489 				FreeRegionInfo(raidPtr, j);
    490 			RF_Free(raidPtr->regionInfo,
    491 				(rf_numParityRegions *
    492 				 sizeof(RF_RegionInfo_t)));
    493 			return (ENOMEM);
    494 		}
    495 		rc = rf_mutex_init(&raidPtr->regionInfo[i].reintMutex);
    496 		if (rc) {
    497 			RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d\n", __FILE__,
    498 			    __LINE__, rc);
    499 			rf_mutex_destroy(&raidPtr->regionInfo[i].mutex);
    500 			for (j = 0; j < i; j++)
    501 				FreeRegionInfo(raidPtr, j);
    502 			RF_Free(raidPtr->regionInfo,
    503 				(rf_numParityRegions *
    504 				 sizeof(RF_RegionInfo_t)));
    505 			return (ENOMEM);
    506 		}
    507 		raidPtr->regionInfo[i].reintInProgress = RF_FALSE;
    508 		raidPtr->regionInfo[i].regionStartAddr =
    509 			raidPtr->regionLogCapacity * i;
    510 		raidPtr->regionInfo[i].parityStartAddr =
    511 			raidPtr->regionParityRange * i;
    512 		if (i < rf_numParityRegions - 1) {
    513 			raidPtr->regionInfo[i].capacity =
    514 				raidPtr->regionLogCapacity;
    515 			raidPtr->regionInfo[i].numSectorsParity =
    516 				raidPtr->regionParityRange;
    517 		} else {
    518 			raidPtr->regionInfo[i].capacity =
    519 				lastRegionCapacity;
    520 			raidPtr->regionInfo[i].numSectorsParity =
    521 				raidPtr->sectorsPerDisk -
    522 				raidPtr->regionParityRange * i;
    523 			if (raidPtr->regionInfo[i].numSectorsParity >
    524 			    maxRegionParityRange)
    525 				maxRegionParityRange =
    526 					raidPtr->regionInfo[i].numSectorsParity;
    527 		}
    528 		raidPtr->regionInfo[i].diskCount = 0;
    529 		RF_ASSERT(raidPtr->regionInfo[i].capacity +
    530 			  raidPtr->regionInfo[i].regionStartAddr <=
    531 			  totalLogCapacity);
    532 		RF_ASSERT(raidPtr->regionInfo[i].parityStartAddr +
    533 			  raidPtr->regionInfo[i].numSectorsParity <=
    534 			  raidPtr->sectorsPerDisk);
    535 		printf("Allocating %d bytes for region %d\n",
    536 		       (int) (raidPtr->regionInfo[i].capacity *
    537 			   sizeof(RF_DiskMap_t)), i);
    538 		RF_Malloc(raidPtr->regionInfo[i].diskMap,
    539 			  (raidPtr->regionInfo[i].capacity *
    540 			   sizeof(RF_DiskMap_t)),
    541 			  (RF_DiskMap_t *));
    542 		if (raidPtr->regionInfo[i].diskMap == NULL) {
    543 			rf_mutex_destroy(&raidPtr->regionInfo[i].mutex);
    544 			rf_mutex_destroy(&raidPtr->regionInfo[i].reintMutex);
    545 			for (j = 0; j < i; j++)
    546 				FreeRegionInfo(raidPtr, j);
    547 			RF_Free(raidPtr->regionInfo,
    548 				(rf_numParityRegions *
    549 				 sizeof(RF_RegionInfo_t)));
    550 			return (ENOMEM);
    551 		}
    552 		raidPtr->regionInfo[i].loggingEnabled = RF_FALSE;
    553 		raidPtr->regionInfo[i].coreLog = NULL;
    554 	}
    555 	rc = rf_ShutdownCreate(listp,
    556 			       rf_ShutdownParityLoggingRegionInfo,
    557 			       raidPtr);
    558 	if (rc) {
    559 		RF_ERRORMSG3("Unable to create shutdown entry file %s line %d rc=%d\n", __FILE__,
    560 		    __LINE__, rc);
    561 		rf_ShutdownParityLoggingRegionInfo(raidPtr);
    562 		return (rc);
    563 	}
    564 	RF_ASSERT(raidPtr->parityLogDiskQueue.threadState == 0);
    565 	raidPtr->parityLogDiskQueue.threadState = RF_PLOG_CREATED;
    566 	rc = RF_CREATE_THREAD(raidPtr->pLogDiskThreadHandle,
    567 			      rf_ParityLoggingDiskManager, raidPtr,"rf_log");
    568 	if (rc) {
    569 		raidPtr->parityLogDiskQueue.threadState = 0;
    570 		RF_ERRORMSG3("Unable to create parity logging disk thread file %s line %d rc=%d\n",
    571 		    __FILE__, __LINE__, rc);
    572 		return (ENOMEM);
    573 	}
    574 	/* wait for thread to start */
    575 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    576 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_RUNNING)) {
    577 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    578 			     raidPtr->parityLogDiskQueue.mutex);
    579 	}
    580 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    581 
    582 	rc = rf_ShutdownCreate(listp, rf_ShutdownParityLogging, raidPtr);
    583 	if (rc) {
    584 		RF_ERRORMSG1("Got rc=%d adding parity logging shutdown event\n", rc);
    585 		rf_ShutdownParityLogging(raidPtr);
    586 		return (rc);
    587 	}
    588 	if (rf_parityLogDebug) {
    589 		printf("                            size of disk log in sectors: %d\n",
    590 		    (int) totalLogCapacity);
    591 		printf("                            total number of parity regions is %d\n", (int) rf_numParityRegions);
    592 		printf("                            nominal sectors of log per parity region is %d\n", (int) raidPtr->regionLogCapacity);
    593 		printf("                            nominal region fragmentation is %d sectors\n", (int) fragmentation);
    594 		printf("                            total number of parity logs is %d\n", raidPtr->numParityLogs);
    595 		printf("                            parity log size is %d sectors\n", raidPtr->numSectorsPerLog);
    596 		printf("                            total in-core log space is %d bytes\n", (int) rf_totalInCoreLogCapacity);
    597 	}
    598 	rf_EnableParityLogging(raidPtr);
    599 
    600 	return (0);
    601 }
    602 
    603 static void
    604 FreeRegionInfo(
    605     RF_Raid_t * raidPtr,
    606     RF_RegionId_t regionID)
    607 {
    608 	RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    609 	RF_Free(raidPtr->regionInfo[regionID].diskMap,
    610 		(raidPtr->regionInfo[regionID].capacity *
    611 		 sizeof(RF_DiskMap_t)));
    612 	if (!rf_forceParityLogReint && raidPtr->regionInfo[regionID].coreLog) {
    613 		rf_ReleaseParityLogs(raidPtr,
    614 				     raidPtr->regionInfo[regionID].coreLog);
    615 		raidPtr->regionInfo[regionID].coreLog = NULL;
    616 	} else {
    617 		RF_ASSERT(raidPtr->regionInfo[regionID].coreLog == NULL);
    618 		RF_ASSERT(raidPtr->regionInfo[regionID].diskCount == 0);
    619 	}
    620 	RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
    621 	rf_mutex_destroy(&raidPtr->regionInfo[regionID].mutex);
    622 	rf_mutex_destroy(&raidPtr->regionInfo[regionID].reintMutex);
    623 }
    624 
    625 
    626 static void
    627 FreeParityLogQueue(
    628     RF_Raid_t * raidPtr,
    629     RF_ParityLogQueue_t * queue)
    630 {
    631 	RF_ParityLog_t *l1, *l2;
    632 
    633 	RF_LOCK_MUTEX(queue->mutex);
    634 	l1 = queue->parityLogs;
    635 	while (l1) {
    636 		l2 = l1;
    637 		l1 = l2->next;
    638 		RF_Free(l2->records, (raidPtr->numSectorsPerLog *
    639 				      sizeof(RF_ParityLogRecord_t)));
    640 		RF_Free(l2, sizeof(RF_ParityLog_t));
    641 	}
    642 	RF_UNLOCK_MUTEX(queue->mutex);
    643 	rf_mutex_destroy(&queue->mutex);
    644 }
    645 
    646 
    647 static void
    648 FreeRegionBufferQueue(RF_RegionBufferQueue_t * queue)
    649 {
    650 	int     i;
    651 
    652 	RF_LOCK_MUTEX(queue->mutex);
    653 	if (queue->availableBuffers != queue->totalBuffers) {
    654 		printf("Attempt to free region queue which is still in use!\n");
    655 		RF_ASSERT(0);
    656 	}
    657 	for (i = 0; i < queue->totalBuffers; i++)
    658 		RF_Free(queue->buffers[i], queue->bufferSize);
    659 	RF_Free(queue->buffers, queue->totalBuffers * sizeof(caddr_t));
    660 	RF_UNLOCK_MUTEX(queue->mutex);
    661 	rf_mutex_destroy(&queue->mutex);
    662 }
    663 
    664 static void
    665 rf_ShutdownParityLoggingRegionInfo(RF_ThreadArg_t arg)
    666 {
    667 	RF_Raid_t *raidPtr;
    668 	RF_RegionId_t i;
    669 
    670 	raidPtr = (RF_Raid_t *) arg;
    671 	if (rf_parityLogDebug) {
    672 		printf("raid%d: ShutdownParityLoggingRegionInfo\n",
    673 		       raidPtr->raidid);
    674 	}
    675 	/* free region information structs */
    676 	for (i = 0; i < rf_numParityRegions; i++)
    677 		FreeRegionInfo(raidPtr, i);
    678 	RF_Free(raidPtr->regionInfo, (rf_numParityRegions *
    679 				      sizeof(raidPtr->regionInfo)));
    680 	raidPtr->regionInfo = NULL;
    681 }
    682 
    683 static void
    684 rf_ShutdownParityLoggingPool(RF_ThreadArg_t arg)
    685 {
    686 	RF_Raid_t *raidPtr;
    687 
    688 	raidPtr = (RF_Raid_t *) arg;
    689 	if (rf_parityLogDebug) {
    690 		printf("raid%d: ShutdownParityLoggingPool\n", raidPtr->raidid);
    691 	}
    692 	/* free contents of parityLogPool */
    693 	FreeParityLogQueue(raidPtr, &raidPtr->parityLogPool);
    694 	RF_Free(raidPtr->parityLogBufferHeap, raidPtr->numParityLogs *
    695 		raidPtr->numSectorsPerLog * raidPtr->bytesPerSector);
    696 }
    697 
    698 static void
    699 rf_ShutdownParityLoggingRegionBufferPool(RF_ThreadArg_t arg)
    700 {
    701 	RF_Raid_t *raidPtr;
    702 
    703 	raidPtr = (RF_Raid_t *) arg;
    704 	if (rf_parityLogDebug) {
    705 		printf("raid%d: ShutdownParityLoggingRegionBufferPool\n",
    706 		       raidPtr->raidid);
    707 	}
    708 	FreeRegionBufferQueue(&raidPtr->regionBufferPool);
    709 }
    710 
    711 static void
    712 rf_ShutdownParityLoggingParityBufferPool(RF_ThreadArg_t arg)
    713 {
    714 	RF_Raid_t *raidPtr;
    715 
    716 	raidPtr = (RF_Raid_t *) arg;
    717 	if (rf_parityLogDebug) {
    718 		printf("raid%d: ShutdownParityLoggingParityBufferPool\n",
    719 		       raidPtr->raidid);
    720 	}
    721 	FreeRegionBufferQueue(&raidPtr->parityBufferPool);
    722 }
    723 
    724 static void
    725 rf_ShutdownParityLoggingDiskQueue(RF_ThreadArg_t arg)
    726 {
    727 	RF_ParityLogData_t *d;
    728 	RF_CommonLogData_t *c;
    729 	RF_Raid_t *raidPtr;
    730 
    731 	raidPtr = (RF_Raid_t *) arg;
    732 	if (rf_parityLogDebug) {
    733 		printf("raid%d: ShutdownParityLoggingDiskQueue\n",
    734 		       raidPtr->raidid);
    735 	}
    736 	/* free disk manager stuff */
    737 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufHead == NULL);
    738 	RF_ASSERT(raidPtr->parityLogDiskQueue.bufTail == NULL);
    739 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintHead == NULL);
    740 	RF_ASSERT(raidPtr->parityLogDiskQueue.reintTail == NULL);
    741 	while (raidPtr->parityLogDiskQueue.freeDataList) {
    742 		d = raidPtr->parityLogDiskQueue.freeDataList;
    743 		raidPtr->parityLogDiskQueue.freeDataList =
    744 			raidPtr->parityLogDiskQueue.freeDataList->next;
    745 		RF_Free(d, sizeof(RF_ParityLogData_t));
    746 	}
    747 	while (raidPtr->parityLogDiskQueue.freeCommonList) {
    748 		c = raidPtr->parityLogDiskQueue.freeCommonList;
    749 		rf_mutex_destroy(&c->mutex);
    750 		raidPtr->parityLogDiskQueue.freeCommonList =
    751 			raidPtr->parityLogDiskQueue.freeCommonList->next;
    752 		RF_Free(c, sizeof(RF_CommonLogData_t));
    753 	}
    754 }
    755 
    756 static void
    757 rf_ShutdownParityLogging(RF_ThreadArg_t arg)
    758 {
    759 	RF_Raid_t *raidPtr;
    760 
    761 	raidPtr = (RF_Raid_t *) arg;
    762 	if (rf_parityLogDebug) {
    763 		printf("raid%d: ShutdownParityLogging\n", raidPtr->raidid);
    764 	}
    765 	/* shutdown disk thread */
    766 	/* This has the desirable side-effect of forcing all regions to be
    767 	 * reintegrated.  This is necessary since all parity log maps are
    768 	 * currently held in volatile memory. */
    769 
    770 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    771 	raidPtr->parityLogDiskQueue.threadState |= RF_PLOG_TERMINATE;
    772 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    773 	RF_SIGNAL_COND(raidPtr->parityLogDiskQueue.cond);
    774 	/*
    775          * pLogDiskThread will now terminate when queues are cleared
    776          * now wait for it to be done
    777          */
    778 	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    779 	while (!(raidPtr->parityLogDiskQueue.threadState & RF_PLOG_SHUTDOWN)) {
    780 		RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
    781 			     raidPtr->parityLogDiskQueue.mutex);
    782 	}
    783 	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
    784 	if (rf_parityLogDebug) {
    785 		printf("raid%d: ShutdownParityLogging done (thread completed)\n", raidPtr->raidid);
    786 	}
    787 }
    788 
    789 int
    790 rf_GetDefaultNumFloatingReconBuffersParityLogging(RF_Raid_t * raidPtr)
    791 {
    792 	return (20);
    793 }
    794 
    795 RF_HeadSepLimit_t
    796 rf_GetDefaultHeadSepLimitParityLogging(RF_Raid_t * raidPtr)
    797 {
    798 	return (10);
    799 }
    800 /* return the region ID for a given RAID address */
    801 RF_RegionId_t
    802 rf_MapRegionIDParityLogging(
    803     RF_Raid_t * raidPtr,
    804     RF_SectorNum_t address)
    805 {
    806 	RF_RegionId_t regionID;
    807 
    808 /*  regionID = address / (raidPtr->regionParityRange * raidPtr->Layout.numDataCol); */
    809 	regionID = address / raidPtr->regionParityRange;
    810 	if (regionID == rf_numParityRegions) {
    811 		/* last region may be larger than other regions */
    812 		regionID--;
    813 	}
    814 	RF_ASSERT(address >= raidPtr->regionInfo[regionID].parityStartAddr);
    815 	RF_ASSERT(address < raidPtr->regionInfo[regionID].parityStartAddr +
    816 		  raidPtr->regionInfo[regionID].numSectorsParity);
    817 	RF_ASSERT(regionID < rf_numParityRegions);
    818 	return (regionID);
    819 }
    820 
    821 
    822 /* given a logical RAID sector, determine physical disk address of data */
    823 void
    824 rf_MapSectorParityLogging(
    825     RF_Raid_t * raidPtr,
    826     RF_RaidAddr_t raidSector,
    827     RF_RowCol_t * row,
    828     RF_RowCol_t * col,
    829     RF_SectorNum_t * diskSector,
    830     int remap)
    831 {
    832 	RF_StripeNum_t SUID = raidSector /
    833 		raidPtr->Layout.sectorsPerStripeUnit;
    834 	*row = 0;
    835 	/* *col = (SUID % (raidPtr->numCol -
    836 	 * raidPtr->Layout.numParityLogCol)); */
    837 	*col = SUID % raidPtr->Layout.numDataCol;
    838 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    839 		raidPtr->Layout.sectorsPerStripeUnit +
    840 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    841 }
    842 
    843 
    844 /* given a logical RAID sector, determine physical disk address of parity  */
    845 void
    846 rf_MapParityParityLogging(
    847     RF_Raid_t * raidPtr,
    848     RF_RaidAddr_t raidSector,
    849     RF_RowCol_t * row,
    850     RF_RowCol_t * col,
    851     RF_SectorNum_t * diskSector,
    852     int remap)
    853 {
    854 	RF_StripeNum_t SUID = raidSector /
    855 		raidPtr->Layout.sectorsPerStripeUnit;
    856 
    857 	*row = 0;
    858 	/* *col =
    859 	 * raidPtr->Layout.numDataCol-(SUID/raidPtr->Layout.numDataCol)%(raidPt
    860 	 * r->numCol - raidPtr->Layout.numParityLogCol); */
    861 	*col = raidPtr->Layout.numDataCol;
    862 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) *
    863 		raidPtr->Layout.sectorsPerStripeUnit +
    864 		(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    865 }
    866 
    867 
    868 /* given a regionID and sector offset, determine the physical disk address of the parity log */
    869 void
    870 rf_MapLogParityLogging(
    871     RF_Raid_t * raidPtr,
    872     RF_RegionId_t regionID,
    873     RF_SectorNum_t regionOffset,
    874     RF_RowCol_t * row,
    875     RF_RowCol_t * col,
    876     RF_SectorNum_t * startSector)
    877 {
    878 	*row = 0;
    879 	*col = raidPtr->numCol - 1;
    880 	*startSector = raidPtr->regionInfo[regionID].regionStartAddr + regionOffset;
    881 }
    882 
    883 
    884 /* given a regionID, determine the physical disk address of the logged
    885    parity for that region */
    886 void
    887 rf_MapRegionParity(
    888     RF_Raid_t * raidPtr,
    889     RF_RegionId_t regionID,
    890     RF_RowCol_t * row,
    891     RF_RowCol_t * col,
    892     RF_SectorNum_t * startSector,
    893     RF_SectorCount_t * numSector)
    894 {
    895 	*row = 0;
    896 	*col = raidPtr->numCol - 2;
    897 	*startSector = raidPtr->regionInfo[regionID].parityStartAddr;
    898 	*numSector = raidPtr->regionInfo[regionID].numSectorsParity;
    899 }
    900 
    901 
    902 /* given a logical RAID address, determine the participating disks in
    903    the stripe */
    904 void
    905 rf_IdentifyStripeParityLogging(
    906     RF_Raid_t * raidPtr,
    907     RF_RaidAddr_t addr,
    908     RF_RowCol_t ** diskids,
    909     RF_RowCol_t * outRow)
    910 {
    911 	RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout,
    912 							   addr);
    913 	RF_ParityLoggingConfigInfo_t *info = (RF_ParityLoggingConfigInfo_t *)
    914 		raidPtr->Layout.layoutSpecificInfo;
    915 	*outRow = 0;
    916 	*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
    917 }
    918 
    919 
    920 void
    921 rf_MapSIDToPSIDParityLogging(
    922     RF_RaidLayout_t * layoutPtr,
    923     RF_StripeNum_t stripeID,
    924     RF_StripeNum_t * psID,
    925     RF_ReconUnitNum_t * which_ru)
    926 {
    927 	*which_ru = 0;
    928 	*psID = stripeID;
    929 }
    930 
    931 
    932 /* select an algorithm for performing an access.  Returns two pointers,
    933  * one to a function that will return information about the DAG, and
    934  * another to a function that will create the dag.
    935  */
    936 void
    937 rf_ParityLoggingDagSelect(
    938     RF_Raid_t * raidPtr,
    939     RF_IoType_t type,
    940     RF_AccessStripeMap_t * asmp,
    941     RF_VoidFuncPtr * createFunc)
    942 {
    943 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
    944 	RF_PhysDiskAddr_t *failedPDA = NULL;
    945 	RF_RowCol_t frow, fcol;
    946 	RF_RowStatus_t rstat;
    947 	int     prior_recon;
    948 
    949 	RF_ASSERT(RF_IO_IS_R_OR_W(type));
    950 
    951 	if (asmp->numDataFailed + asmp->numParityFailed > 1) {
    952 		RF_ERRORMSG("Multiple disks failed in a single group!  Aborting I/O operation.\n");
    953 		 /* *infoFunc = */ *createFunc = NULL;
    954 		return;
    955 	} else
    956 		if (asmp->numDataFailed + asmp->numParityFailed == 1) {
    957 
    958 			/* if under recon & already reconstructed, redirect
    959 			 * the access to the spare drive and eliminate the
    960 			 * failure indication */
    961 			failedPDA = asmp->failedPDAs[0];
    962 			frow = failedPDA->row;
    963 			fcol = failedPDA->col;
    964 			rstat = raidPtr->status[failedPDA->row];
    965 			prior_recon = (rstat == rf_rs_reconfigured) || (
    966 			    (rstat == rf_rs_reconstructing) ?
    967 			    rf_CheckRUReconstructed(raidPtr->reconControl[frow]->reconMap, failedPDA->startSector) : 0
    968 			    );
    969 			if (prior_recon) {
    970 				RF_RowCol_t or = failedPDA->row, oc = failedPDA->col;
    971 				RF_SectorNum_t oo = failedPDA->startSector;
    972 				if (layoutPtr->map->flags &
    973 				    RF_DISTRIBUTE_SPARE) {
    974 					/* redirect to dist spare space */
    975 
    976 					if (failedPDA == asmp->parityInfo) {
    977 
    978 						/* parity has failed */
    979 						(layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
    980 						    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
    981 
    982 						if (asmp->parityInfo->next) {	/* redir 2nd component,
    983 										 * if any */
    984 							RF_PhysDiskAddr_t *p = asmp->parityInfo->next;
    985 							RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit;
    986 							p->row = failedPDA->row;
    987 							p->col = failedPDA->col;
    988 							p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) +
    989 							    SUoffs;	/* cheating:
    990 									 * startSector is not
    991 									 * really a RAID address */
    992 						}
    993 					} else
    994 						if (asmp->parityInfo->next && failedPDA == asmp->parityInfo->next) {
    995 							RF_ASSERT(0);	/* should not ever
    996 									 * happen */
    997 						} else {
    998 
    999 							/* data has failed */
   1000 							(layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
   1001 							    &failedPDA->col, &failedPDA->startSector, RF_REMAP);
   1002 
   1003 						}
   1004 
   1005 				} else {
   1006 					/* redirect to dedicated spare space */
   1007 
   1008 					failedPDA->row = raidPtr->Disks[frow][fcol].spareRow;
   1009 					failedPDA->col = raidPtr->Disks[frow][fcol].spareCol;
   1010 
   1011 					/* the parity may have two distinct
   1012 					 * components, both of which may need
   1013 					 * to be redirected */
   1014 					if (asmp->parityInfo->next) {
   1015 						if (failedPDA == asmp->parityInfo) {
   1016 							failedPDA->next->row = failedPDA->row;
   1017 							failedPDA->next->col = failedPDA->col;
   1018 						} else
   1019 							if (failedPDA == asmp->parityInfo->next) {	/* paranoid:  should never occur */
   1020 								asmp->parityInfo->row = failedPDA->row;
   1021 								asmp->parityInfo->col = failedPDA->col;
   1022 							}
   1023 					}
   1024 				}
   1025 
   1026 				RF_ASSERT(failedPDA->col != -1);
   1027 
   1028 				if (rf_dagDebug || rf_mapDebug) {
   1029 					printf("raid%d: Redirected type '%c' r %d c %d o %ld -> r %d c %d o %ld\n",
   1030 					    raidPtr->raidid, type, or, oc, (long) oo, failedPDA->row, failedPDA->col, (long) failedPDA->startSector);
   1031 				}
   1032 				asmp->numDataFailed = asmp->numParityFailed = 0;
   1033 			}
   1034 		}
   1035 	if (type == RF_IO_TYPE_READ) {
   1036 
   1037 		if (asmp->numDataFailed == 0)
   1038 			*createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG;
   1039 		else
   1040 			*createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG;
   1041 
   1042 	} else {
   1043 
   1044 
   1045 		/* if mirroring, always use large writes.  If the access
   1046 		 * requires two distinct parity updates, always do a small
   1047 		 * write.  If the stripe contains a failure but the access
   1048 		 * does not, do a small write. The first conditional
   1049 		 * (numStripeUnitsAccessed <= numDataCol/2) uses a
   1050 		 * less-than-or-equal rather than just a less-than because
   1051 		 * when G is 3 or 4, numDataCol/2 is 1, and I want
   1052 		 * single-stripe-unit updates to use just one disk. */
   1053 		if ((asmp->numDataFailed + asmp->numParityFailed) == 0) {
   1054 			if (((asmp->numStripeUnitsAccessed <=
   1055 			      (layoutPtr->numDataCol / 2)) &&
   1056 			     (layoutPtr->numDataCol != 1)) ||
   1057 			    (asmp->parityInfo->next != NULL) ||
   1058 			    rf_CheckStripeForFailures(raidPtr, asmp)) {
   1059 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingSmallWriteDAG;
   1060 			} else
   1061 				*createFunc = (RF_VoidFuncPtr) rf_CreateParityLoggingLargeWriteDAG;
   1062 		} else
   1063 			if (asmp->numParityFailed == 1)
   1064 				*createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG;
   1065 			else
   1066 				if (asmp->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit)
   1067 					*createFunc = NULL;
   1068 				else
   1069 					*createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG;
   1070 	}
   1071 }
   1072 #endif				/* RF_INCLUDE_PARITYLOGGING > 0 */
   1073