/*      $NetBSD: rf_raid5.c,v 1.20 2019/02/09 03:34:00 christos Exp $   */
/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Mark Holland
 *
 * 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_raid5.c -- implements RAID Level 5
 *
 *****************************************************************************/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rf_raid5.c,v 1.20 2019/02/09 03:34:00 christos Exp $");

#include <dev/raidframe/raidframevar.h>

#include "rf_raid.h"
#include "rf_raid5.h"
#include "rf_dag.h"
#include "rf_dagffrd.h"
#include "rf_dagffwr.h"
#include "rf_dagdegrd.h"
#include "rf_dagdegwr.h"
#include "rf_dagutils.h"
#include "rf_general.h"
#include "rf_map.h"
#include "rf_utils.h"

typedef struct RF_Raid5ConfigInfo_s {
        RF_RowCol_t **stripeIdentifier; /* filled in at config time and used
                                         * by IdentifyStripe */
}       RF_Raid5ConfigInfo_t;

int
rf_ConfigureRAID5(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr,
                  RF_Config_t *cfgPtr)
{
        RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
        RF_Raid5ConfigInfo_t *info;
        RF_RowCol_t i, j, startdisk;

        /* create a RAID level 5 configuration structure */
        info = RF_MallocAndAdd(sizeof(*info), raidPtr->cleanupList);
        if (info == NULL)
                return (ENOMEM);
        layoutPtr->layoutSpecificInfo = (void *) info;

        /* the stripe identifier must identify the disks in each stripe, IN
         * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
        info->stripeIdentifier = rf_make_2d_array(raidPtr->numCol, raidPtr->numCol, raidPtr->cleanupList);
        if (info->stripeIdentifier == NULL)
                return (ENOMEM);
        startdisk = 0;
        for (i = 0; i < raidPtr->numCol; i++) {
                for (j = 0; j < raidPtr->numCol; j++) {
                        info->stripeIdentifier[i][j] = (startdisk + j) % raidPtr->numCol;
                }
                if ((--startdisk) < 0)
                        startdisk = raidPtr->numCol - 1;
        }

        /* fill in the remaining layout parameters */
        layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
        layoutPtr->numDataCol = raidPtr->numCol - 1;
        layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
        layoutPtr->numParityCol = 1;
        layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;

        raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;

        return (0);
}

int
rf_GetDefaultNumFloatingReconBuffersRAID5(RF_Raid_t *raidPtr)
{
        return (20);
}

RF_HeadSepLimit_t
rf_GetDefaultHeadSepLimitRAID5(RF_Raid_t *raidPtr)
{
        return (10);
}
#if !defined(__NetBSD__) && !defined(_KERNEL)
/* not currently used */
int
rf_ShutdownRAID5(RF_Raid_t *raidPtr)
{
        return (0);
}
#endif

void
rf_MapSectorRAID5(RF_Raid_t *raidPtr, RF_RaidAddr_t raidSector,
                  RF_RowCol_t *col, RF_SectorNum_t *diskSector,
                  int remap)
{
        RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
        *col = (SUID % raidPtr->numCol);
        *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
            (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
}

void
rf_MapParityRAID5(RF_Raid_t *raidPtr, RF_RaidAddr_t raidSector,
                  RF_RowCol_t *col, RF_SectorNum_t *diskSector,
                  int remap)
{
        RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;

        *col = raidPtr->Layout.numDataCol - (SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
        *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
            (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
}

void
rf_IdentifyStripeRAID5(RF_Raid_t *raidPtr, RF_RaidAddr_t addr,
                       RF_RowCol_t **diskids)
{
        RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr);
        RF_Raid5ConfigInfo_t *info = (RF_Raid5ConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;

        *diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
}

void
rf_MapSIDToPSIDRAID5(RF_RaidLayout_t *layoutPtr,
                     RF_StripeNum_t stripeID,
                     RF_StripeNum_t *psID, RF_ReconUnitNum_t *which_ru)
{
        *which_ru = 0;
        *psID = stripeID;
}
/* select an algorithm for performing an access.  Returns two pointers,
 * one to a function that will return information about the DAG, and
 * another to a function that will create the dag.
 */
void
rf_RaidFiveDagSelect(RF_Raid_t *raidPtr, RF_IoType_t type,
                     RF_AccessStripeMap_t *asmap,
                     RF_VoidFuncPtr *createFunc)
{
        RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
        RF_PhysDiskAddr_t *failedPDA = NULL;
        RF_RowCol_t fcol;
        RF_RowStatus_t rstat;
        int     prior_recon;

        RF_ASSERT(RF_IO_IS_R_OR_W(type));

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

        if (asmap->numDataFailed + asmap->numParityFailed == 1) {

                /* if under recon & already reconstructed, redirect
                 * the access to the spare drive and eliminate the
                 * failure indication */
                failedPDA = asmap->failedPDAs[0];
                fcol = failedPDA->col;
                rstat = raidPtr->status;
                prior_recon = (rstat == rf_rs_reconfigured) || (
                            (rstat == rf_rs_reconstructing) ?
                            rf_CheckRUReconstructed(raidPtr->reconControl->reconMap, failedPDA->startSector) : 0
                            );
                if (prior_recon) {
#if RF_DEBUG_DAG > 0 || RF_DEBUG_MAP > 0
                        RF_RowCol_t oc = failedPDA->col;
                        RF_SectorNum_t oo = failedPDA->startSector;
#endif
#if RF_INCLUDE_PARITY_DECLUSTERING_DS > 0
                        if (layoutPtr->map->flags & RF_DISTRIBUTE_SPARE) {      /* redirect to dist
                                                                                 * spare space */

                                if (failedPDA == asmap->parityInfo) {

                                        /* parity has failed */
                                        (layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress,
                                                                     &failedPDA->col, &failedPDA->startSector, RF_REMAP);

                                        if (asmap->parityInfo->next) {  /* redir 2nd component,
                                                                         * if any */
                                                RF_PhysDiskAddr_t *p = asmap->parityInfo->next;
                                                RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit;
                                                p->col = failedPDA->col;
                                                p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) +
                                                        SUoffs; /* cheating:
                                                                 * startSector is not
                                                                 * really a RAID address */
                                        }
                                } else
                                        if (asmap->parityInfo->next && failedPDA == asmap->parityInfo->next) {
                                                RF_ASSERT(0);   /* should not ever
                                                                 * happen */
                                        } else {

                                                /* data has failed */
                                                (layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress,
                                                                             &failedPDA->col, &failedPDA->startSector, RF_REMAP);

                                        }

                        } else {
#endif
                                /* redirect to dedicated spare space */

                                failedPDA->col = raidPtr->Disks[fcol].spareCol;

                                /* the parity may have two distinct
                                 * components, both of which may need
                                 * to be redirected */
                                if (asmap->parityInfo->next) {
                                        if (failedPDA == asmap->parityInfo) {
                                                failedPDA->next->col = failedPDA->col;
                                        } else
                                                if (failedPDA == asmap->parityInfo->next) {     /* paranoid:  should
                                                                                                 * never occur */
                                                        asmap->parityInfo->col = failedPDA->col;
                                                }
                                }
#if RF_INCLUDE_PARITY_DECLUSTERING_DS > 0
                        }
#endif
                        RF_ASSERT(failedPDA->col != -1);

#if RF_DEBUG_DAG > 0 || RF_DEBUG_MAP > 0
                        if (rf_dagDebug || rf_mapDebug) {
                                printf("raid%d: Redirected type '%c' c %d o %ld -> c %d o %ld\n",
                                       raidPtr->raidid, type, oc,
                                       (long) oo, failedPDA->col,
                                       (long) failedPDA->startSector);
                        }
#endif
                        asmap->numDataFailed = asmap->numParityFailed = 0;
                }
        }
        /* all dags begin/end with block/unblock node therefore, hdrSucc &
         * termAnt counts should always be 1 also, these counts should not be
         * visible outside dag creation routines - manipulating the counts
         * here should be removed */
        if (type == RF_IO_TYPE_READ) {
                if (asmap->numDataFailed == 0)
                        *createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG;
                else
                        *createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG;
        } else {


                /* if mirroring, always use large writes.  If the access
                 * requires two distinct parity updates, always do a small
                 * write.  If the stripe contains a failure but the access
                 * does not, do a small write. The first conditional
                 * (numStripeUnitsAccessed <= numDataCol/2) uses a
                 * less-than-or-equal rather than just a less-than because
                 * when G is 3 or 4, numDataCol/2 is 1, and I want
                 * single-stripe-unit updates to use just one disk. */
                if ((asmap->numDataFailed + asmap->numParityFailed) == 0) {
                        if (rf_suppressLocksAndLargeWrites ||
                            (((asmap->numStripeUnitsAccessed <= (layoutPtr->numDataCol / 2)) && (layoutPtr->numDataCol != 1)) ||
                                (asmap->parityInfo->next != NULL) || rf_CheckStripeForFailures(raidPtr, asmap))) {
                                *createFunc = (RF_VoidFuncPtr) rf_CreateSmallWriteDAG;
                        } else
                                *createFunc = (RF_VoidFuncPtr) rf_CreateLargeWriteDAG;
                } else {
                        if (asmap->numParityFailed == 1)
                                *createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG;
                        else
                                if (asmap->numStripeUnitsAccessed != 1 && (failedPDA == NULL || failedPDA->numSector != layoutPtr->sectorsPerStripeUnit))
                                        *createFunc = NULL;
                                else
                                        *createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG;
                }
        }
}