dev/raidframe/rf_interdecluster.c

/*	$NetBSD: rf_interdecluster.c,v 1.2 1999/01/26 02:33:58 oster Exp $	*/
/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Khalil Amiri
 *
 * 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 (at) 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_interdecluster.c -- implements interleaved declustering
 *
 ************************************************************/


#include "rf_types.h"
#include "rf_raid.h"
#include "rf_interdecluster.h"
#include "rf_dag.h"
#include "rf_dagutils.h"
#include "rf_dagfuncs.h"
#include "rf_threadid.h"
#include "rf_general.h"
#include "rf_utils.h"
#include "rf_dagffrd.h"
#include "rf_dagdegrd.h"
#include "rf_dagffwr.h"
#include "rf_dagdegwr.h"

typedef struct RF_InterdeclusterConfigInfo_s {
  RF_RowCol_t       **stripeIdentifier;   /* filled in at config time
                                           * and used by IdentifyStripe */
  RF_StripeCount_t    numSparingRegions;
  RF_StripeCount_t    stripeUnitsPerSparingRegion;
  RF_SectorNum_t      mirrorStripeOffset;
} RF_InterdeclusterConfigInfo_t;

int rf_ConfigureInterDecluster(
  RF_ShutdownList_t  **listp,
  RF_Raid_t           *raidPtr,
  RF_Config_t         *cfgPtr)
{
  RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
  RF_StripeCount_t num_used_stripeUnitsPerDisk;
  RF_InterdeclusterConfigInfo_t *info;
  RF_RowCol_t i, tmp, SUs_per_region;

  /* create an Interleaved Declustering configuration structure */
  RF_MallocAndAdd(info, sizeof(RF_InterdeclusterConfigInfo_t), (RF_InterdeclusterConfigInfo_t *),
			raidPtr->cleanupList);
  if (info == NULL)
    return(ENOMEM);
  layoutPtr->layoutSpecificInfo = (void *) info;

  /*  fill in the config structure.  */
  SUs_per_region = raidPtr->numCol * (raidPtr->numCol - 1);
  info->stripeIdentifier = rf_make_2d_array(SUs_per_region, 2 , raidPtr->cleanupList);
  if (info->stripeIdentifier == NULL)
    return(ENOMEM);
  for (i=0; i< SUs_per_region; i++) {
      info->stripeIdentifier[i][0] = i / (raidPtr->numCol-1);
      tmp = i / raidPtr->numCol;
      info->stripeIdentifier[i][1] = (i+1+tmp) % raidPtr->numCol;
    }

  /* no spare tables */
  RF_ASSERT(raidPtr->numRow == 1);

  /* fill in the remaining layout parameters */

  /* total number of stripes should a multiple of 2*numCol: Each sparing region consists of
   2*numCol stripes: n-1 primary copy, n-1 secondary copy and 2 for spare .. */
    num_used_stripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk - (layoutPtr->stripeUnitsPerDisk %
	(2*raidPtr->numCol) );
  info->numSparingRegions = num_used_stripeUnitsPerDisk / (2*raidPtr->numCol);
  /* this is in fact the number of stripe units (that are primary data copies) in the sparing region */
  info->stripeUnitsPerSparingRegion = raidPtr->numCol * (raidPtr->numCol - 1);
  info->mirrorStripeOffset = info->numSparingRegions * (raidPtr->numCol+1);
  layoutPtr->numStripe = info->numSparingRegions * info->stripeUnitsPerSparingRegion;
  layoutPtr->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit << raidPtr->logBytesPerSector;
  layoutPtr->numDataCol = 1;
  layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
  layoutPtr->numParityCol = 1;

  layoutPtr->dataStripeUnitsPerDisk = num_used_stripeUnitsPerDisk;

  raidPtr->sectorsPerDisk =
    num_used_stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit;

  raidPtr->totalSectors =
    (layoutPtr->numStripe) * layoutPtr->sectorsPerStripeUnit;

  layoutPtr->stripeUnitsPerDisk = raidPtr->sectorsPerDisk / layoutPtr->sectorsPerStripeUnit;

  return(0);
}

int rf_GetDefaultNumFloatingReconBuffersInterDecluster(RF_Raid_t *raidPtr)
{
  return(30);
}

RF_HeadSepLimit_t rf_GetDefaultHeadSepLimitInterDecluster(RF_Raid_t *raidPtr)
{
  return(raidPtr->sectorsPerDisk);
}

RF_ReconUnitCount_t rf_GetNumSpareRUsInterDecluster(
  RF_Raid_t  *raidPtr)
{
  RF_InterdeclusterConfigInfo_t *info = (RF_InterdeclusterConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;

  return ( 2 * ((RF_ReconUnitCount_t) info->numSparingRegions) );
	/* the layout uses two stripe units per disk as spare within each sparing region */
}

/* Maps to the primary copy of the data, i.e. the first mirror pair */
void rf_MapSectorInterDecluster(
  RF_Raid_t         *raidPtr,
  RF_RaidAddr_t      raidSector,
  RF_RowCol_t       *row,
  RF_RowCol_t       *col,
  RF_SectorNum_t    *diskSector,
  int                remap)
{
 RF_InterdeclusterConfigInfo_t *info = (RF_InterdeclusterConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;
 RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
 RF_StripeNum_t su_offset_into_disk, mirror_su_offset_into_disk;
 RF_StripeNum_t sparing_region_id, index_within_region;
 int col_before_remap;

 *row = 0;
 sparing_region_id = SUID / info->stripeUnitsPerSparingRegion;
 index_within_region = SUID % info->stripeUnitsPerSparingRegion;
 su_offset_into_disk = index_within_region % (raidPtr->numCol-1);
 mirror_su_offset_into_disk = index_within_region / raidPtr->numCol;
 col_before_remap = index_within_region / (raidPtr->numCol-1);

 if (!remap) {
        *col = col_before_remap;;
        *diskSector = ( su_offset_into_disk + ( (raidPtr->numCol-1) * sparing_region_id) ) *
                        raidPtr->Layout.sectorsPerStripeUnit;
        *diskSector += (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
      }
 else {
      /* remap sector to spare space...*/
      *diskSector = sparing_region_id * (raidPtr->numCol+1) * raidPtr->Layout.sectorsPerStripeUnit;
      *diskSector += (raidPtr->numCol-1) * raidPtr->Layout.sectorsPerStripeUnit;
      *diskSector += (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
      *col = (index_within_region + 1 + mirror_su_offset_into_disk) % raidPtr->numCol;
      *col = (*col + 1) % raidPtr->numCol;
      if (*col == col_before_remap) *col = (*col + 1) % raidPtr->numCol;
   }
}

/* Maps to the second copy of the mirror pair. */
void rf_MapParityInterDecluster(
  RF_Raid_t       *raidPtr,
  RF_RaidAddr_t    raidSector,
  RF_RowCol_t     *row,
  RF_RowCol_t     *col,
  RF_SectorNum_t  *diskSector,
  int              remap)
{
  RF_InterdeclusterConfigInfo_t *info = (RF_InterdeclusterConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;
  RF_StripeNum_t sparing_region_id, index_within_region, mirror_su_offset_into_disk;
  RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
  int col_before_remap;

  sparing_region_id = SUID / info->stripeUnitsPerSparingRegion;
  index_within_region = SUID % info->stripeUnitsPerSparingRegion;
  mirror_su_offset_into_disk = index_within_region / raidPtr->numCol;
  col_before_remap = (index_within_region + 1 + mirror_su_offset_into_disk) % raidPtr->numCol;

  *row = 0;
  if (!remap) {
        *col = col_before_remap;
        *diskSector =  info->mirrorStripeOffset * raidPtr->Layout.sectorsPerStripeUnit;
        *diskSector += sparing_region_id * (raidPtr->numCol-1)  * raidPtr->Layout.sectorsPerStripeUnit;
        *diskSector += mirror_su_offset_into_disk * raidPtr->Layout.sectorsPerStripeUnit;
        *diskSector += (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
       }
  else {
        /* remap parity to spare space ... */
        *diskSector =  sparing_region_id * (raidPtr->numCol+1) * raidPtr->Layout.sectorsPerStripeUnit;
        *diskSector += (raidPtr->numCol) * raidPtr->Layout.sectorsPerStripeUnit;
        *diskSector += (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
        *col = index_within_region / (raidPtr->numCol-1);
        *col = (*col + 1) % raidPtr->numCol;
        if (*col == col_before_remap) *col = (*col + 1) % raidPtr->numCol;
  }
}

void rf_IdentifyStripeInterDecluster(
  RF_Raid_t        *raidPtr,
  RF_RaidAddr_t     addr,
  RF_RowCol_t     **diskids,
  RF_RowCol_t      *outRow)
{
  RF_InterdeclusterConfigInfo_t *info = (RF_InterdeclusterConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;
  RF_StripeNum_t SUID;

  SUID = addr / raidPtr->Layout.sectorsPerStripeUnit;
  SUID = SUID % info->stripeUnitsPerSparingRegion;

  *outRow = 0;
  *diskids = info->stripeIdentifier[ SUID ];
}

void rf_MapSIDToPSIDInterDecluster(
  RF_RaidLayout_t    *layoutPtr,
  RF_StripeNum_t      stripeID,
  RF_StripeNum_t     *psID,
  RF_ReconUnitNum_t  *which_ru)
{
  *which_ru = 0;
  *psID = stripeID;
}

/******************************************************************************
 * select a graph to perform a single-stripe access
 *
 * Parameters:  raidPtr    - description of the physical array
 *              type       - type of operation (read or write) requested
 *              asmap      - logical & physical addresses for this access
 *              createFunc - name of function to use to create the graph
 *****************************************************************************/

void rf_RAIDIDagSelect(
  RF_Raid_t             *raidPtr,
  RF_IoType_t            type,
  RF_AccessStripeMap_t  *asmap,
  RF_VoidFuncPtr *createFunc)
{
  RF_ASSERT(RF_IO_IS_R_OR_W(type));

  if (asmap->numDataFailed + asmap->numParityFailed > 1) {
    RF_ERRORMSG("Multiple disks failed in a single group!  Aborting I/O operation.\n");
    *createFunc = NULL;
    return;
  }

  *createFunc = (type == RF_IO_TYPE_READ) ? (RF_VoidFuncPtr)rf_CreateFaultFreeReadDAG : (RF_VoidFuncPtr)rf_CreateRaidOneWriteDAG;
  if (type == RF_IO_TYPE_READ) {
    if (asmap->numDataFailed == 0)
      *createFunc = (RF_VoidFuncPtr)rf_CreateMirrorPartitionReadDAG;
    else
      *createFunc = (RF_VoidFuncPtr)rf_CreateRaidOneDegradedReadDAG;
  }
  else
    *createFunc = (RF_VoidFuncPtr)rf_CreateRaidOneWriteDAG;
}