freebsd-skq/sys/dev/raidframe/rf_declusterPQ.c
obrien c63dab466c Use __FBSDID().
Also some minor style cleanups.
2003-08-24 17:55:58 +00:00

494 lines
20 KiB
C

/* $NetBSD: rf_declusterPQ.c,v 1.5 2001/01/26 14:06:17 oster Exp $ */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Copyright (c) 1995 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Daniel Stodolsky, Mark Holland, Jim Zelenka
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*--------------------------------------------------
* rf_declusterPQ.c
*
* mapping code for declustered P & Q or declustered EvenOdd
* much code borrowed from rf_decluster.c
*
*--------------------------------------------------*/
#include <dev/raidframe/rf_archs.h>
#include <dev/raidframe/rf_types.h>
#include <dev/raidframe/rf_raid.h>
#include <dev/raidframe/rf_configure.h>
#include <dev/raidframe/rf_decluster.h>
#include <dev/raidframe/rf_declusterPQ.h>
#include <dev/raidframe/rf_debugMem.h>
#include <dev/raidframe/rf_utils.h>
#include <dev/raidframe/rf_alloclist.h>
#include <dev/raidframe/rf_general.h>
#if (RF_INCLUDE_PARITY_DECLUSTERING_PQ > 0) || (RF_INCLUDE_EVENODD > 0)
/* configuration code */
int
rf_ConfigureDeclusteredPQ(
RF_ShutdownList_t ** listp,
RF_Raid_t * raidPtr,
RF_Config_t * cfgPtr)
{
RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
int b, v, k, r, lambda; /* block design params */
int i, j, l;
int *first_avail_slot;
int complete_FT_count, SUID;
RF_DeclusteredConfigInfo_t *info;
int numCompleteFullTablesPerDisk;
int PUsPerDisk, spareRegionDepthInPUs, numCompleteSpareRegionsPerDisk = 0,
extraPUsPerDisk;
int totSparePUsPerDisk;
int diskOffsetOfLastFullTableInSUs, SpareSpaceInSUs;
char *cfgBuf = (char *) (cfgPtr->layoutSpecific);
cfgBuf += RF_SPAREMAP_NAME_LEN;
b = *((int *) cfgBuf);
cfgBuf += sizeof(int);
v = *((int *) cfgBuf);
cfgBuf += sizeof(int);
k = *((int *) cfgBuf);
cfgBuf += sizeof(int);
r = *((int *) cfgBuf);
cfgBuf += sizeof(int);
lambda = *((int *) cfgBuf);
cfgBuf += sizeof(int);
raidPtr->noRotate = *((int *) cfgBuf);
cfgBuf += sizeof(int);
if (k <= 2) {
printf("RAIDFRAME: k=%d, minimum value 2\n", k);
return (EINVAL);
}
/* 1. create layout specific structure */
RF_MallocAndAdd(info, sizeof(RF_DeclusteredConfigInfo_t), (RF_DeclusteredConfigInfo_t *), raidPtr->cleanupList);
if (info == NULL)
return (ENOMEM);
layoutPtr->layoutSpecificInfo = (void *) info;
/* the sparemaps are generated assuming that parity is rotated, so we
* issue a warning if both distributed sparing and no-rotate are on at
* the same time */
if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE) && raidPtr->noRotate) {
RF_ERRORMSG("Warning: distributed sparing specified without parity rotation.\n");
}
if (raidPtr->numCol != v) {
RF_ERRORMSG2("RAID: config error: table element count (%d) not equal to no. of cols (%d)\n", v, raidPtr->numCol);
return (EINVAL);
}
/* 3. set up the values used in devRaidMap */
info->BlocksPerTable = b;
info->NumParityReps = info->groupSize = k;
info->PUsPerBlock = k - 2; /* PQ */
info->SUsPerTable = b * info->PUsPerBlock * layoutPtr->SUsPerPU; /* b blks, k-1 SUs each */
info->SUsPerFullTable = k * info->SUsPerTable; /* rot k times */
info->SUsPerBlock = info->PUsPerBlock * layoutPtr->SUsPerPU;
info->TableDepthInPUs = (b * k) / v;
info->FullTableDepthInPUs = info->TableDepthInPUs * k; /* k repetitions */
/* used only in distributed sparing case */
info->FullTablesPerSpareRegion = (v - 1) / rf_gcd(r, v - 1); /* (v-1)/gcd fulltables */
info->TablesPerSpareRegion = k * info->FullTablesPerSpareRegion;
info->SpareSpaceDepthPerRegionInSUs = (r * info->TablesPerSpareRegion / (v - 1)) * layoutPtr->SUsPerPU;
/* check to make sure the block design is sufficiently small */
if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
if (info->FullTableDepthInPUs * layoutPtr->SUsPerPU + info->SpareSpaceDepthPerRegionInSUs > layoutPtr->stripeUnitsPerDisk) {
RF_ERRORMSG3("RAID: config error: Full Table depth (%d) + Spare Space (%d) larger than disk size (%d) (BD too big)\n",
(int) info->FullTableDepthInPUs,
(int) info->SpareSpaceDepthPerRegionInSUs,
(int) layoutPtr->stripeUnitsPerDisk);
return (EINVAL);
}
} else {
if (info->TableDepthInPUs * layoutPtr->SUsPerPU > layoutPtr->stripeUnitsPerDisk) {
RF_ERRORMSG2("RAID: config error: Table depth (%d) larger than disk size (%d) (BD too big)\n",
(int) (info->TableDepthInPUs * layoutPtr->SUsPerPU),
(int) layoutPtr->stripeUnitsPerDisk);
return (EINVAL);
}
}
/* compute the size of each disk, and the number of tables in the last
* fulltable (which need not be complete) */
if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
PUsPerDisk = layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU;
spareRegionDepthInPUs = (info->TablesPerSpareRegion * info->TableDepthInPUs +
(info->TablesPerSpareRegion * info->TableDepthInPUs) / (v - 1));
info->SpareRegionDepthInSUs = spareRegionDepthInPUs * layoutPtr->SUsPerPU;
numCompleteSpareRegionsPerDisk = PUsPerDisk / spareRegionDepthInPUs;
info->NumCompleteSRs = numCompleteSpareRegionsPerDisk;
extraPUsPerDisk = PUsPerDisk % spareRegionDepthInPUs;
/* assume conservatively that we need the full amount of spare
* space in one region in order to provide spares for the
* partial spare region at the end of the array. We set "i"
* to the number of tables in the partial spare region. This
* may actually include some fulltables. */
extraPUsPerDisk -= (info->SpareSpaceDepthPerRegionInSUs / layoutPtr->SUsPerPU);
if (extraPUsPerDisk <= 0)
i = 0;
else
i = extraPUsPerDisk / info->TableDepthInPUs;
complete_FT_count = raidPtr->numRow * (numCompleteSpareRegionsPerDisk * (info->TablesPerSpareRegion / k) + i / k);
info->FullTableLimitSUID = complete_FT_count * info->SUsPerFullTable;
info->ExtraTablesPerDisk = i % k;
/* note that in the last spare region, the spare space is
* complete even though data/parity space is not */
totSparePUsPerDisk = (numCompleteSpareRegionsPerDisk + 1) * (info->SpareSpaceDepthPerRegionInSUs / layoutPtr->SUsPerPU);
info->TotSparePUsPerDisk = totSparePUsPerDisk;
layoutPtr->stripeUnitsPerDisk =
((complete_FT_count / raidPtr->numRow) * info->FullTableDepthInPUs + /* data & parity space */
info->ExtraTablesPerDisk * info->TableDepthInPUs +
totSparePUsPerDisk /* spare space */
) * layoutPtr->SUsPerPU;
layoutPtr->dataStripeUnitsPerDisk =
(complete_FT_count * info->FullTableDepthInPUs + info->ExtraTablesPerDisk * info->TableDepthInPUs)
* layoutPtr->SUsPerPU * (k - 1) / k;
} else {
/* non-dist spare case: force each disk to contain an
* integral number of tables */
layoutPtr->stripeUnitsPerDisk /= (info->TableDepthInPUs * layoutPtr->SUsPerPU);
layoutPtr->stripeUnitsPerDisk *= (info->TableDepthInPUs * layoutPtr->SUsPerPU);
/* compute the number of tables in the last fulltable, which
* need not be complete */
complete_FT_count =
((layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU) / info->FullTableDepthInPUs) * raidPtr->numRow;
info->FullTableLimitSUID = complete_FT_count * info->SUsPerFullTable;
info->ExtraTablesPerDisk =
((layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerPU) / info->TableDepthInPUs) % k;
}
raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit;
/* find the disk offset of the stripe unit where the last fulltable
* starts */
numCompleteFullTablesPerDisk = complete_FT_count / raidPtr->numRow;
diskOffsetOfLastFullTableInSUs = numCompleteFullTablesPerDisk * info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
SpareSpaceInSUs = numCompleteSpareRegionsPerDisk * info->SpareSpaceDepthPerRegionInSUs;
diskOffsetOfLastFullTableInSUs += SpareSpaceInSUs;
info->DiskOffsetOfLastSpareSpaceChunkInSUs =
diskOffsetOfLastFullTableInSUs + info->ExtraTablesPerDisk * info->TableDepthInPUs * layoutPtr->SUsPerPU;
}
info->DiskOffsetOfLastFullTableInSUs = diskOffsetOfLastFullTableInSUs;
info->numCompleteFullTablesPerDisk = numCompleteFullTablesPerDisk;
/* 4. create and initialize the lookup tables */
info->LayoutTable = rf_make_2d_array(b, k, raidPtr->cleanupList);
if (info->LayoutTable == NULL)
return (ENOMEM);
info->OffsetTable = rf_make_2d_array(b, k, raidPtr->cleanupList);
if (info->OffsetTable == NULL)
return (ENOMEM);
info->BlockTable = rf_make_2d_array(info->TableDepthInPUs * layoutPtr->SUsPerPU, raidPtr->numCol, raidPtr->cleanupList);
if (info->BlockTable == NULL)
return (ENOMEM);
first_avail_slot = (int *) rf_make_1d_array(v, NULL);
if (first_avail_slot == NULL)
return (ENOMEM);
for (i = 0; i < b; i++)
for (j = 0; j < k; j++)
info->LayoutTable[i][j] = *cfgBuf++;
/* initialize offset table */
for (i = 0; i < b; i++)
for (j = 0; j < k; j++) {
info->OffsetTable[i][j] = first_avail_slot[info->LayoutTable[i][j]];
first_avail_slot[info->LayoutTable[i][j]]++;
}
/* initialize block table */
for (SUID = l = 0; l < layoutPtr->SUsPerPU; l++) {
for (i = 0; i < b; i++) {
for (j = 0; j < k; j++) {
info->BlockTable[(info->OffsetTable[i][j] * layoutPtr->SUsPerPU) + l]
[info->LayoutTable[i][j]] = SUID;
}
SUID++;
}
}
rf_free_1d_array(first_avail_slot, v);
/* 5. set up the remaining redundant-but-useful parameters */
raidPtr->totalSectors = (k * complete_FT_count + raidPtr->numRow * info->ExtraTablesPerDisk) *
info->SUsPerTable * layoutPtr->sectorsPerStripeUnit;
layoutPtr->numStripe = (raidPtr->totalSectors / layoutPtr->sectorsPerStripeUnit) / (k - 2);
/* strange evaluation order below to try and minimize overflow
* problems */
layoutPtr->dataSectorsPerStripe = (k - 2) * layoutPtr->sectorsPerStripeUnit;
layoutPtr->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit << raidPtr->logBytesPerSector;
layoutPtr->numDataCol = k - 2;
layoutPtr->numParityCol = 2;
return (0);
}
int
rf_GetDefaultNumFloatingReconBuffersPQ(RF_Raid_t * raidPtr)
{
int def_decl;
def_decl = rf_GetDefaultNumFloatingReconBuffersDeclustered(raidPtr);
return (RF_MAX(3 * raidPtr->numCol, def_decl));
}
void
rf_MapSectorDeclusteredPQ(
RF_Raid_t * raidPtr,
RF_RaidAddr_t raidSector,
RF_RowCol_t * row,
RF_RowCol_t * col,
RF_SectorNum_t * diskSector,
int remap)
{
RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
RF_StripeNum_t BlockID, BlockOffset, RepIndex;
RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
RF_StripeNum_t base_suid = 0, outSU, SpareRegion = 0, SpareSpace = 0;
rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
FullTableID = SUID / sus_per_fulltable; /* fulltable ID within array
* (across rows) */
*row = FullTableID % raidPtr->numRow;
FullTableID /= raidPtr->numRow; /* convert to fulltable ID on this
* disk */
if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
}
FullTableOffset = SUID % sus_per_fulltable;
TableID = FullTableOffset / info->SUsPerTable;
TableOffset = FullTableOffset - TableID * info->SUsPerTable;
BlockID = TableOffset / info->PUsPerBlock;
BlockOffset = TableOffset - BlockID * info->PUsPerBlock;
BlockID %= info->BlocksPerTable;
RF_ASSERT(BlockOffset < info->groupSize - 2);
/*
TableIDs go from 0 .. GroupSize-1 inclusive.
PUsPerBlock is k-2.
We want the tableIDs to rotate from the
right, so use GroupSize
*/
RepIndex = info->groupSize - 1 - TableID;
RF_ASSERT(RepIndex >= 0);
if (!raidPtr->noRotate) {
if (TableID == 0)
BlockOffset++; /* P on last drive, Q on first */
else
BlockOffset += ((BlockOffset >= RepIndex) ? 2 : 0); /* skip over PQ */
RF_ASSERT(BlockOffset < info->groupSize);
*col = info->LayoutTable[BlockID][BlockOffset];
}
/* remap to distributed spare space if indicated */
if (remap) {
rf_remap_to_spare_space(layoutPtr, info, *row, FullTableID, TableID, BlockID, (base_suid) ? 1 : 0, SpareRegion, col, &outSU);
} else {
outSU = base_suid;
outSU += FullTableID * fulltable_depth; /* offs to strt of FT */
outSU += SpareSpace; /* skip rsvd spare space */
outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU; /* offs to strt of tble */
outSU += info->OffsetTable[BlockID][BlockOffset] * layoutPtr->SUsPerPU; /* offs to the PU */
}
outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock); /* offs to the SU within
* a PU */
/* convert SUs to sectors, and, if not aligned to SU boundary, add in
* offset to sector */
*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
}
void
rf_MapParityDeclusteredPQ(
RF_Raid_t * raidPtr,
RF_RaidAddr_t raidSector,
RF_RowCol_t * row,
RF_RowCol_t * col,
RF_SectorNum_t * diskSector,
int remap)
{
RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
RF_StripeNum_t BlockID, BlockOffset, RepIndex;
RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
RF_StripeNum_t base_suid = 0, outSU, SpareRegion, SpareSpace = 0;
rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
/* compute row & (possibly) spare space exactly as before */
FullTableID = SUID / sus_per_fulltable;
*row = FullTableID % raidPtr->numRow;
FullTableID /= raidPtr->numRow; /* convert to fulltable ID on this
* disk */
if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
}
/* compute BlockID and RepIndex exactly as before */
FullTableOffset = SUID % sus_per_fulltable;
TableID = FullTableOffset / info->SUsPerTable;
TableOffset = FullTableOffset - TableID * info->SUsPerTable;
BlockID = TableOffset / info->PUsPerBlock;
BlockOffset = TableOffset - BlockID * info->PUsPerBlock;
BlockID %= info->BlocksPerTable;
/* the parity block is in the position indicated by RepIndex */
RepIndex = (raidPtr->noRotate) ? info->PUsPerBlock : info->groupSize - 1 - TableID;
*col = info->LayoutTable[BlockID][RepIndex];
if (remap)
RF_PANIC();
/* compute sector as before, except use RepIndex instead of
* BlockOffset */
outSU = base_suid;
outSU += FullTableID * fulltable_depth;
outSU += SpareSpace; /* skip rsvd spare space */
outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;
outSU += info->OffsetTable[BlockID][RepIndex] * layoutPtr->SUsPerPU;
outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);
*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
}
void
rf_MapQDeclusteredPQ(
RF_Raid_t * raidPtr,
RF_RaidAddr_t raidSector,
RF_RowCol_t * row,
RF_RowCol_t * col,
RF_SectorNum_t * diskSector,
int remap)
{
RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
RF_StripeNum_t SUID = raidSector / layoutPtr->sectorsPerStripeUnit;
RF_StripeNum_t FullTableID, FullTableOffset, TableID, TableOffset;
RF_StripeNum_t BlockID, BlockOffset, RepIndex, RepIndexQ;
RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
RF_StripeNum_t base_suid = 0, outSU, SpareRegion, SpareSpace = 0;
rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
/* compute row & (possibly) spare space exactly as before */
FullTableID = SUID / sus_per_fulltable;
*row = FullTableID % raidPtr->numRow;
FullTableID /= raidPtr->numRow; /* convert to fulltable ID on this
* disk */
if ((raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE)) {
SpareRegion = FullTableID / info->FullTablesPerSpareRegion;
SpareSpace = SpareRegion * info->SpareSpaceDepthPerRegionInSUs;
}
/* compute BlockID and RepIndex exactly as before */
FullTableOffset = SUID % sus_per_fulltable;
TableID = FullTableOffset / info->SUsPerTable;
TableOffset = FullTableOffset - TableID * info->SUsPerTable;
BlockID = TableOffset / info->PUsPerBlock;
BlockOffset = TableOffset - BlockID * info->PUsPerBlock;
BlockID %= info->BlocksPerTable;
/* the q block is in the position indicated by RepIndex */
RepIndex = (raidPtr->noRotate) ? info->PUsPerBlock : info->groupSize - 1 - TableID;
RepIndexQ = ((RepIndex == (info->groupSize - 1)) ? 0 : RepIndex + 1);
*col = info->LayoutTable[BlockID][RepIndexQ];
if (remap)
RF_PANIC();
/* compute sector as before, except use RepIndex instead of
* BlockOffset */
outSU = base_suid;
outSU += FullTableID * fulltable_depth;
outSU += SpareSpace; /* skip rsvd spare space */
outSU += TableID * info->TableDepthInPUs * layoutPtr->SUsPerPU;
outSU += TableOffset / (info->BlocksPerTable * info->PUsPerBlock);
outSU += info->OffsetTable[BlockID][RepIndexQ] * layoutPtr->SUsPerPU;
*diskSector = outSU * layoutPtr->sectorsPerStripeUnit + (raidSector % layoutPtr->sectorsPerStripeUnit);
}
/* returns an array of ints identifying the disks that comprise the stripe containing the indicated address.
* the caller must _never_ attempt to modify this array.
*/
void
rf_IdentifyStripeDeclusteredPQ(
RF_Raid_t * raidPtr,
RF_RaidAddr_t addr,
RF_RowCol_t ** diskids,
RF_RowCol_t * outRow)
{
RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
RF_DeclusteredConfigInfo_t *info = (RF_DeclusteredConfigInfo_t *) layoutPtr->layoutSpecificInfo;
RF_StripeCount_t sus_per_fulltable = info->SUsPerFullTable;
RF_StripeCount_t fulltable_depth = info->FullTableDepthInPUs * layoutPtr->SUsPerPU;
RF_StripeNum_t base_suid = 0;
RF_StripeNum_t SUID = rf_RaidAddressToStripeUnitID(layoutPtr, addr);
RF_StripeNum_t stripeID, FullTableID;
int tableOffset;
rf_decluster_adjust_params(layoutPtr, &SUID, &sus_per_fulltable, &fulltable_depth, &base_suid);
FullTableID = SUID / sus_per_fulltable; /* fulltable ID within array
* (across rows) */
*outRow = FullTableID % raidPtr->numRow;
stripeID = rf_StripeUnitIDToStripeID(layoutPtr, SUID); /* find stripe offset
* into array */
tableOffset = (stripeID % info->BlocksPerTable); /* find offset into
* block design table */
*diskids = info->LayoutTable[tableOffset];
}
#endif /* (RF_INCLUDE_PARITY_DECLUSTERING_PQ > 0) || (RF_INCLUDE_EVENODD > 0) */