xref: /netbsd-src/sys/dev/raidframe/rf_declusterPQ.c (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1 /*	$NetBSD: rf_declusterPQ.c,v 1.3 1999/02/05 00:06:09 oster Exp $	*/
2 /*
3  * Copyright (c) 1995 Carnegie-Mellon University.
4  * All rights reserved.
5  *
6  * Authors: Daniel Stodolsky, Mark Holland, Jim Zelenka
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@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  * rf_declusterPQ.c
31  *
32  * mapping code for declustered P & Q or declustered EvenOdd
33  * much code borrowed from rf_decluster.c
34  *
35  *--------------------------------------------------*/
36 
37 
38 #include "rf_types.h"
39 #include "rf_raid.h"
40 #include "rf_configure.h"
41 #include "rf_decluster.h"
42 #include "rf_declusterPQ.h"
43 #include "rf_debugMem.h"
44 #include "rf_utils.h"
45 #include "rf_alloclist.h"
46 #include "rf_general.h"
47 
48 /* configuration code */
49 
50 int
51 rf_ConfigureDeclusteredPQ(
52     RF_ShutdownList_t ** listp,
53     RF_Raid_t * raidPtr,
54     RF_Config_t * cfgPtr)
55 {
56 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
57 	int     b, v, k, r, lambda;	/* block design params */
58 	int     i, j, l;
59 	int    *first_avail_slot;
60 	int     complete_FT_count, SUID;
61 	RF_DeclusteredConfigInfo_t *info;
62 	int     numCompleteFullTablesPerDisk;
63 	int     PUsPerDisk, spareRegionDepthInPUs, numCompleteSpareRegionsPerDisk = 0,
64 	        extraPUsPerDisk;
65 	int     totSparePUsPerDisk;
66 	int     diskOffsetOfLastFullTableInSUs, SpareSpaceInSUs;
67 	char   *cfgBuf = (char *) (cfgPtr->layoutSpecific);
68 
69 	cfgBuf += RF_SPAREMAP_NAME_LEN;
70 
71 	b = *((int *) cfgBuf);
72 	cfgBuf += sizeof(int);
73 	v = *((int *) cfgBuf);
74 	cfgBuf += sizeof(int);
75 	k = *((int *) cfgBuf);
76 	cfgBuf += sizeof(int);
77 	r = *((int *) cfgBuf);
78 	cfgBuf += sizeof(int);
79 	lambda = *((int *) cfgBuf);
80 	cfgBuf += sizeof(int);
81 	raidPtr->noRotate = *((int *) cfgBuf);
82 	cfgBuf += sizeof(int);
83 
84 	if (k <= 2) {
85 		printf("RAIDFRAME: k=%d, minimum value 2\n", k);
86 		return (EINVAL);
87 	}
88 	/* 1. create layout specific structure */
89 	RF_MallocAndAdd(info, sizeof(RF_DeclusteredConfigInfo_t), (RF_DeclusteredConfigInfo_t *), raidPtr->cleanupList);
90 	if (info == NULL)
91 		return (ENOMEM);
92 	layoutPtr->layoutSpecificInfo = (void *) info;
93 
94 	/* the sparemaps are generated assuming that parity is rotated, so we
95 	 * issue a warning if both distributed sparing and no-rotate are on at
96 	 * the same time */
97 	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE) && raidPtr->noRotate) {
98 		RF_ERRORMSG("Warning:  distributed sparing specified without parity rotation.\n");
99 	}
100 	if (raidPtr->numCol != v) {
101 		RF_ERRORMSG2("RAID: config error: table element count (%d) not equal to no. of cols (%d)\n", v, raidPtr->numCol);
102 		return (EINVAL);
103 	}
104 	/* 3.  set up the values used in devRaidMap */
105 	info->BlocksPerTable = b;
106 	info->NumParityReps = info->groupSize = k;
107 	info->PUsPerBlock = k - 2;	/* PQ */
108 	info->SUsPerTable = b * info->PUsPerBlock * layoutPtr->SUsPerPU;	/* b blks, k-1 SUs each */
109 	info->SUsPerFullTable = k * info->SUsPerTable;	/* rot k times */
110 	info->SUsPerBlock = info->PUsPerBlock * layoutPtr->SUsPerPU;
111 	info->TableDepthInPUs = (b * k) / v;
112 	info->FullTableDepthInPUs = info->TableDepthInPUs * k;	/* k repetitions */
113 
114 	/* used only in distributed sparing case */
115 	info->FullTablesPerSpareRegion = (v - 1) / rf_gcd(r, v - 1);	/* (v-1)/gcd fulltables */
116 	info->TablesPerSpareRegion = k * info->FullTablesPerSpareRegion;
117 	info->SpareSpaceDepthPerRegionInSUs = (r * info->TablesPerSpareRegion / (v - 1)) * layoutPtr->SUsPerPU;
118 
119 	/* check to make sure the block design is sufficiently small */
120 	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
121 		if (info->FullTableDepthInPUs * layoutPtr->SUsPerPU + info->SpareSpaceDepthPerRegionInSUs > layoutPtr->stripeUnitsPerDisk) {
122 			RF_ERRORMSG3("RAID: config error: Full Table depth (%d) + Spare Space (%d) larger than disk size (%d) (BD too big)\n",
123 			    (int) info->FullTableDepthInPUs,
124 			    (int) info->SpareSpaceDepthPerRegionInSUs,
125 			    (int) layoutPtr->stripeUnitsPerDisk);
126 			return (EINVAL);
127 		}
128 	} else {
129 		if (info->TableDepthInPUs * layoutPtr->SUsPerPU > layoutPtr->stripeUnitsPerDisk) {
130 			RF_ERRORMSG2("RAID: config error: Table depth (%d) larger than disk size (%d) (BD too big)\n",
131 			    (int) (info->TableDepthInPUs * layoutPtr->SUsPerPU),
132 			    (int) layoutPtr->stripeUnitsPerDisk);
133 			return (EINVAL);
134 		}
135 	}
136 
137 
138 	/* compute the size of each disk, and the number of tables in the last
139 	 * fulltable (which need not be complete) */
140 	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
141 
142 		PUsPerDisk = layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU;
143 		spareRegionDepthInPUs = (info->TablesPerSpareRegion * info->TableDepthInPUs +
144 		    (info->TablesPerSpareRegion * info->TableDepthInPUs) / (v - 1));
145 		info->SpareRegionDepthInSUs = spareRegionDepthInPUs * layoutPtr->SUsPerPU;
146 
147 		numCompleteSpareRegionsPerDisk = PUsPerDisk / spareRegionDepthInPUs;
148 		info->NumCompleteSRs = numCompleteSpareRegionsPerDisk;
149 		extraPUsPerDisk = PUsPerDisk % spareRegionDepthInPUs;
150 
151 		/* assume conservatively that we need the full amount of spare
152 		 * space in one region in order to provide spares for the
153 		 * partial spare region at the end of the array.  We set "i"
154 		 * to the number of tables in the partial spare region.  This
155 		 * may actually include some fulltables. */
156 		extraPUsPerDisk -= (info->SpareSpaceDepthPerRegionInSUs / layoutPtr->SUsPerPU);
157 		if (extraPUsPerDisk <= 0)
158 			i = 0;
159 		else
160 			i = extraPUsPerDisk / info->TableDepthInPUs;
161 
162 		complete_FT_count = raidPtr->numRow * (numCompleteSpareRegionsPerDisk * (info->TablesPerSpareRegion / k) + i / k);
163 		info->FullTableLimitSUID = complete_FT_count * info->SUsPerFullTable;
164 		info->ExtraTablesPerDisk = i % k;
165 
166 		/* note that in the last spare region, the spare space is
167 		 * complete even though data/parity space is not */
168 		totSparePUsPerDisk = (numCompleteSpareRegionsPerDisk + 1) * (info->SpareSpaceDepthPerRegionInSUs / layoutPtr->SUsPerPU);
169 		info->TotSparePUsPerDisk = totSparePUsPerDisk;
170 
171 		layoutPtr->stripeUnitsPerDisk =
172 		    ((complete_FT_count / raidPtr->numRow) * info->FullTableDepthInPUs +	/* data & parity space */
173 		    info->ExtraTablesPerDisk * info->TableDepthInPUs +
174 		    totSparePUsPerDisk	/* spare space */
175 		    ) * layoutPtr->SUsPerPU;
176 		layoutPtr->dataStripeUnitsPerDisk =
177 		    (complete_FT_count * info->FullTableDepthInPUs + info->ExtraTablesPerDisk * info->TableDepthInPUs)
178 		    * layoutPtr->SUsPerPU * (k - 1) / k;
179 
180 	} else {
181 		/* non-dist spare case:  force each disk to contain an
182 		 * integral number of tables */
183 		layoutPtr->stripeUnitsPerDisk /= (info->TableDepthInPUs * layoutPtr->SUsPerPU);
184 		layoutPtr->stripeUnitsPerDisk *= (info->TableDepthInPUs * layoutPtr->SUsPerPU);
185 
186 		/* compute the number of tables in the last fulltable, which
187 		 * need not be complete */
188 		complete_FT_count =
189 		    ((layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU) / info->FullTableDepthInPUs) * raidPtr->numRow;
190 
191 		info->FullTableLimitSUID = complete_FT_count * info->SUsPerFullTable;
192 		info->ExtraTablesPerDisk =
193 		    ((layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU) / info->TableDepthInPUs) % k;
194 	}
195 
196 	raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit;
197 
198 	/* find the disk offset of the stripe unit where the last fulltable
199 	 * starts */
200 	numCompleteFullTablesPerDisk = complete_FT_count / raidPtr->numRow;
201 	diskOffsetOfLastFullTableInSUs = numCompleteFullTablesPerDisk * info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
202 	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
203 		SpareSpaceInSUs = numCompleteSpareRegionsPerDisk * info->SpareSpaceDepthPerRegionInSUs;
204 		diskOffsetOfLastFullTableInSUs += SpareSpaceInSUs;
205 		info->DiskOffsetOfLastSpareSpaceChunkInSUs =
206 		    diskOffsetOfLastFullTableInSUs + info->ExtraTablesPerDisk * info->TableDepthInPUs * layoutPtr->SUsPerPU;
207 	}
208 	info->DiskOffsetOfLastFullTableInSUs = diskOffsetOfLastFullTableInSUs;
209 	info->numCompleteFullTablesPerDisk = numCompleteFullTablesPerDisk;
210 
211 	/* 4.  create and initialize the lookup tables */
212 	info->LayoutTable = rf_make_2d_array(b, k, raidPtr->cleanupList);
213 	if (info->LayoutTable == NULL)
214 		return (ENOMEM);
215 	info->OffsetTable = rf_make_2d_array(b, k, raidPtr->cleanupList);
216 	if (info->OffsetTable == NULL)
217 		return (ENOMEM);
218 	info->BlockTable = rf_make_2d_array(info->TableDepthInPUs * layoutPtr->SUsPerPU, raidPtr->numCol, raidPtr->cleanupList);
219 	if (info->BlockTable == NULL)
220 		return (ENOMEM);
221 
222 	first_avail_slot = (int *) rf_make_1d_array(v, NULL);
223 	if (first_avail_slot == NULL)
224 		return (ENOMEM);
225 
226 	for (i = 0; i < b; i++)
227 		for (j = 0; j < k; j++)
228 			info->LayoutTable[i][j] = *cfgBuf++;
229 
230 	/* initialize offset table */
231 	for (i = 0; i < b; i++)
232 		for (j = 0; j < k; j++) {
233 			info->OffsetTable[i][j] = first_avail_slot[info->LayoutTable[i][j]];
234 			first_avail_slot[info->LayoutTable[i][j]]++;
235 		}
236 
237 	/* initialize block table */
238 	for (SUID = l = 0; l < layoutPtr->SUsPerPU; l++) {
239 		for (i = 0; i < b; i++) {
240 			for (j = 0; j < k; j++) {
241 				info->BlockTable[(info->OffsetTable[i][j] * layoutPtr->SUsPerPU) + l]
242 				    [info->LayoutTable[i][j]] = SUID;
243 			}
244 			SUID++;
245 		}
246 	}
247 
248 	rf_free_1d_array(first_avail_slot, v);
249 
250 	/* 5.  set up the remaining redundant-but-useful parameters */
251 
252 	raidPtr->totalSectors = (k * complete_FT_count + raidPtr->numRow * info->ExtraTablesPerDisk) *
253 	    info->SUsPerTable * layoutPtr->sectorsPerStripeUnit;
254 	layoutPtr->numStripe = (raidPtr->totalSectors / layoutPtr->sectorsPerStripeUnit) / (k - 2);
255 
256 	/* strange evaluation order below to try and minimize overflow
257 	 * problems */
258 
259 	layoutPtr->dataSectorsPerStripe = (k - 2) * layoutPtr->sectorsPerStripeUnit;
260 	layoutPtr->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit << raidPtr->logBytesPerSector;
261 	layoutPtr->numDataCol = k - 2;
262 	layoutPtr->numParityCol = 2;
263 
264 	return (0);
265 }
266 
267 int
268 rf_GetDefaultNumFloatingReconBuffersPQ(RF_Raid_t * raidPtr)
269 {
270 	int     def_decl;
271 
272 	def_decl = rf_GetDefaultNumFloatingReconBuffersDeclustered(raidPtr);
273 	return (RF_MAX(3 * raidPtr->numCol, def_decl));
274 }
275 
276 void
277 rf_MapSectorDeclusteredPQ(
278     RF_Raid_t * raidPtr,
279     RF_RaidAddr_t raidSector,
280     RF_RowCol_t * row,
281     RF_RowCol_t * col,
282     RF_SectorNum_t * diskSector,
283     int remap)
284 {
285 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
286 	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
287 	RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
288 	RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
289 	RF_StripeNum_t BlockID, BlockOffset, RepIndex;
290 	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
291 	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
292 	RF_StripeNum_t base_suid = 0, outSU, SpareRegion = 0, SpareSpace = 0;
293 
294 	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
295 
296 	FullTableID = SUID / sus_per_fulltable;	/* fulltable ID within array
297 						 * (across rows) */
298 	*row = FullTableID % raidPtr->numRow;
299 	FullTableID /= raidPtr->numRow;	/* convert to fulltable ID on this
300 					 * disk */
301 	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
302 		SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
303 		SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
304 	}
305 	FullTableOffset = SUID % sus_per_fulltable;
306 	TableID = FullTableOffset / info->SUsPerTable;
307 	TableOffset = FullTableOffset - TableID * info->SUsPerTable;
308 	BlockID = TableOffset / info->PUsPerBlock;
309 	BlockOffset = TableOffset - BlockID * info->PUsPerBlock;
310 	BlockID %= info->BlocksPerTable;
311 	RF_ASSERT(BlockOffset < info->groupSize - 2);
312 	/*
313            TableIDs go from 0 .. GroupSize-1 inclusive.
314            PUsPerBlock is k-2.
315            We want the tableIDs to rotate from the
316            right, so use GroupSize
317            */
318 	RepIndex = info->groupSize - 1 - TableID;
319 	RF_ASSERT(RepIndex >= 0);
320 	if (!raidPtr->noRotate) {
321 		if (TableID == 0)
322 			BlockOffset++;	/* P on last drive, Q on first */
323 		else
324 			BlockOffset += ((BlockOffset >= RepIndex) ? 2 : 0);	/* skip over PQ */
325 		RF_ASSERT(BlockOffset < info->groupSize);
326 		*col = info->LayoutTable[BlockID][BlockOffset];
327 	}
328 	/* remap to distributed spare space if indicated */
329 	if (remap) {
330 		rf_remap_to_spare_space(layoutPtr, info, *row, FullTableID, TableID, BlockID, (base_suid) ? 1 : 0, SpareRegion, col, &outSU);
331 	} else {
332 
333 		outSU = base_suid;
334 		outSU += FullTableID * fulltable_depth;	/* offs to strt of FT */
335 		outSU += SpareSpace;	/* skip rsvd spare space */
336 		outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;	/* offs to strt of tble */
337 		outSU += info->OffsetTable[BlockID][BlockOffset] * layoutPtr->SUsPerPU;	/* offs to the PU */
338 	}
339 	outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);	/* offs to the SU within
340 										 * a PU */
341 
342 	/* convert SUs to sectors, and, if not aligned to SU boundary, add in
343 	 * offset to sector */
344 	*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
345 }
346 
347 
348 void
349 rf_MapParityDeclusteredPQ(
350     RF_Raid_t * raidPtr,
351     RF_RaidAddr_t raidSector,
352     RF_RowCol_t * row,
353     RF_RowCol_t * col,
354     RF_SectorNum_t * diskSector,
355     int remap)
356 {
357 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
358 	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
359 	RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
360 	RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
361 	RF_StripeNum_t BlockID, BlockOffset, RepIndex;
362 	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
363 	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
364 	RF_StripeNum_t base_suid = 0, outSU, SpareRegion, SpareSpace = 0;
365 
366 	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
367 
368 	/* compute row & (possibly) spare space exactly as before */
369 	FullTableID = SUID / sus_per_fulltable;
370 	*row = FullTableID % raidPtr->numRow;
371 	FullTableID /= raidPtr->numRow;	/* convert to fulltable ID on this
372 					 * disk */
373 	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
374 		SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
375 		SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
376 	}
377 	/* compute BlockID and RepIndex exactly as before */
378 	FullTableOffset = SUID % sus_per_fulltable;
379 	TableID = FullTableOffset / info->SUsPerTable;
380 	TableOffset = FullTableOffset - TableID * info->SUsPerTable;
381 	BlockID = TableOffset / info->PUsPerBlock;
382 	BlockOffset = TableOffset - BlockID * info->PUsPerBlock;
383 	BlockID %= info->BlocksPerTable;
384 
385 	/* the parity block is in the position indicated by RepIndex */
386 	RepIndex = (raidPtr->noRotate) ? info->PUsPerBlock : info->groupSize - 1 - TableID;
387 	*col = info->LayoutTable[BlockID][RepIndex];
388 
389 	if (remap)
390 		RF_PANIC();
391 
392 	/* compute sector as before, except use RepIndex instead of
393 	 * BlockOffset */
394 	outSU = base_suid;
395 	outSU += FullTableID * fulltable_depth;
396 	outSU += SpareSpace;	/* skip rsvd spare space */
397 	outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;
398 	outSU += info->OffsetTable[BlockID][RepIndex] * layoutPtr->SUsPerPU;
399 	outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);
400 
401 	*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
402 }
403 
404 void
405 rf_MapQDeclusteredPQ(
406     RF_Raid_t * raidPtr,
407     RF_RaidAddr_t raidSector,
408     RF_RowCol_t * row,
409     RF_RowCol_t * col,
410     RF_SectorNum_t * diskSector,
411     int remap)
412 {
413 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
414 	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
415 	RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
416 	RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
417 	RF_StripeNum_t BlockID, BlockOffset, RepIndex, RepIndexQ;
418 	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
419 	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
420 	RF_StripeNum_t base_suid = 0, outSU, SpareRegion, SpareSpace = 0;
421 
422 	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
423 
424 	/* compute row & (possibly) spare space exactly as before */
425 	FullTableID = SUID / sus_per_fulltable;
426 	*row = FullTableID % raidPtr->numRow;
427 	FullTableID /= raidPtr->numRow;	/* convert to fulltable ID on this
428 					 * disk */
429 	if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
430 		SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
431 		SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
432 	}
433 	/* compute BlockID and RepIndex exactly as before */
434 	FullTableOffset = SUID % sus_per_fulltable;
435 	TableID = FullTableOffset / info->SUsPerTable;
436 	TableOffset = FullTableOffset - TableID * info->SUsPerTable;
437 	BlockID = TableOffset / info->PUsPerBlock;
438 	BlockOffset = TableOffset - BlockID * info->PUsPerBlock;
439 	BlockID %= info->BlocksPerTable;
440 
441 	/* the q block is in the position indicated by RepIndex */
442 	RepIndex = (raidPtr->noRotate) ? info->PUsPerBlock : info->groupSize - 1 - TableID;
443 	RepIndexQ = ((RepIndex == (info->groupSize - 1)) ? 0 : RepIndex + 1);
444 	*col = info->LayoutTable[BlockID][RepIndexQ];
445 
446 	if (remap)
447 		RF_PANIC();
448 
449 	/* compute sector as before, except use RepIndex instead of
450 	 * BlockOffset */
451 	outSU = base_suid;
452 	outSU += FullTableID * fulltable_depth;
453 	outSU += SpareSpace;	/* skip rsvd spare space */
454 	outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;
455 	outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);
456 
457 	outSU += info->OffsetTable[BlockID][RepIndexQ] * layoutPtr->SUsPerPU;
458 	*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
459 }
460 /* returns an array of ints identifying the disks that comprise the stripe containing the indicated address.
461  * the caller must _never_ attempt to modify this array.
462  */
463 void
464 rf_IdentifyStripeDeclusteredPQ(
465     RF_Raid_t * raidPtr,
466     RF_RaidAddr_t addr,
467     RF_RowCol_t ** diskids,
468     RF_RowCol_t * outRow)
469 {
470 	RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
471 	RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
472 	RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
473 	RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
474 	RF_StripeNum_t base_suid = 0;
475 	RF_StripeNum_t SUID = rf_RaidAddressToStripeUnitID(layoutPtr, addr);
476 	RF_StripeNum_t stripeID, FullTableID;
477 	int     tableOffset;
478 
479 	rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
480 	FullTableID = SUID / sus_per_fulltable;	/* fulltable ID within array
481 						 * (across rows) */
482 	*outRow = FullTableID % raidPtr->numRow;
483 	stripeID = rf_StripeUnitIDToStripeID(layoutPtr, SUID);	/* find stripe offset
484 								 * into array */
485 	tableOffset = (stripeID % info->BlocksPerTable);	/* find offset into
486 								 * block design table */
487 	*diskids = info->LayoutTable[tableOffset];
488 }
489