/*	$OpenBSD: rf_interdecluster.c,v 1.4 2002/12/16 07:01:04 tdeval Exp $	*/
/*	$NetBSD: rf_interdecluster.c,v 1.4 2000/01/07 03:41:00 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@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_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 {
	/* Filled in at config time and used by IdentifyStripe. */
	RF_RowCol_t	**stripeIdentifier;
	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;
	RF_StripeNum_t 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;
}
