/*      $NetBSD: rf_map.c,v 1.51 2021/07/23 00:54:45 oster 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  [email protected]
*  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.
*/

/**************************************************************************
*
* map.c -- main code for mapping RAID addresses to physical disk addresses
*
**************************************************************************/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rf_map.c,v 1.51 2021/07/23 00:54:45 oster Exp $");

#include <dev/raidframe/raidframevar.h>

#include "rf_threadstuff.h"
#include "rf_raid.h"
#include "rf_general.h"
#include "rf_map.h"
#include "rf_shutdown.h"

static void rf_FreePDAList(RF_Raid_t *raidPtr, RF_PhysDiskAddr_t *pda_list);
static void rf_FreeASMList(RF_Raid_t *raidPtr, RF_AccessStripeMap_t *asm_list);

/***************************************************************************
*
* MapAccess -- main 1st order mapping routine.  Maps an access in the
* RAID address space to the corresponding set of physical disk
* addresses.  The result is returned as a list of AccessStripeMap
* structures, one per stripe accessed.  Each ASM structure contains a
* pointer to a list of PhysDiskAddr structures, which describe the
* physical locations touched by the user access.  Note that this
* routine returns only static mapping information, i.e. the list of
* physical addresses returned does not necessarily identify the set
* of physical locations that will actually be read or written.  The
* routine also maps the parity.  The physical disk location returned
* always indicates the entire parity unit, even when only a subset of
* it is being accessed.  This is because an access that is not stripe
* unit aligned but that spans a stripe unit boundary may require
* access two distinct portions of the parity unit, and we can't yet
* tell which portion(s) we'll actually need.  We leave it up to the
* algorithm selection code to decide what subset of the parity unit
* to access.  Note that addresses in the RAID address space must
* always be maintained as longs, instead of ints.
*
* This routine returns NULL if numBlocks is 0
*
* raidAddress - starting address in RAID address space
* numBlocks   - number of blocks in RAID address space to access
* buffer      - buffer to supply/receive data
* remap       - 1 => remap address to spare space
***************************************************************************/

RF_AccessStripeMapHeader_t *
rf_MapAccess(RF_Raid_t *raidPtr, RF_RaidAddr_t raidAddress,
            RF_SectorCount_t numBlocks, void *buffer, int remap)
{
       RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
       RF_AccessStripeMapHeader_t *asm_hdr = NULL;
       RF_AccessStripeMap_t *asm_list = NULL, *asm_p = NULL;
       int     faultsTolerated = layoutPtr->map->faultsTolerated;
       /* we'll change raidAddress along the way */
       RF_RaidAddr_t startAddress = raidAddress;
       RF_RaidAddr_t endAddress = raidAddress + numBlocks;
       RF_RaidDisk_t *disks = raidPtr->Disks;
       RF_PhysDiskAddr_t *pda_p;
#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)
       RF_PhysDiskAddr_t *pda_q;
#endif
       RF_StripeCount_t numStripes = 0;
       RF_RaidAddr_t stripeRealEndAddress, stripeEndAddress,
               nextStripeUnitAddress;
       RF_RaidAddr_t startAddrWithinStripe, lastRaidAddr;
       RF_StripeCount_t totStripes;
       RF_StripeNum_t stripeID, lastSID, SUID, lastSUID;
       RF_AccessStripeMap_t *asmList, *t_asm;
       RF_PhysDiskAddr_t *pdaList, *t_pda;

       /* allocate all the ASMs and PDAs up front */
       lastRaidAddr = raidAddress + numBlocks - 1;
       stripeID = rf_RaidAddressToStripeID(layoutPtr, raidAddress);
       lastSID = rf_RaidAddressToStripeID(layoutPtr, lastRaidAddr);
       totStripes = lastSID - stripeID + 1;
       SUID = rf_RaidAddressToStripeUnitID(layoutPtr, raidAddress);
       lastSUID = rf_RaidAddressToStripeUnitID(layoutPtr, lastRaidAddr);

       asmList = rf_AllocASMList(raidPtr, totStripes);

       /* may also need pda(s) per stripe for parity */
       pdaList = rf_AllocPDAList(raidPtr, lastSUID - SUID + 1 +
                                 faultsTolerated * totStripes);


       if (raidAddress + numBlocks > raidPtr->totalSectors) {
               RF_ERRORMSG1("Unable to map access because offset (%d) was invalid\n",
                   (int) raidAddress);
               return (NULL);
       }
#if RF_DEBUG_MAP
       if (rf_mapDebug)
               rf_PrintRaidAddressInfo(raidPtr, raidAddress, numBlocks);
#endif
       for (; raidAddress < endAddress;) {
               /* make the next stripe structure */
               RF_ASSERT(asmList);
               t_asm = asmList;
               asmList = asmList->next;
               memset(t_asm, 0, sizeof(*t_asm));
               if (!asm_p)
                       asm_list = asm_p = t_asm;
               else {
                       asm_p->next = t_asm;
                       asm_p = asm_p->next;
               }
               numStripes++;

               /* map SUs from current location to the end of the stripe */
               asm_p->stripeID =       /* rf_RaidAddressToStripeID(layoutPtr,
                       raidAddress) */ stripeID++;
               stripeRealEndAddress = rf_RaidAddressOfNextStripeBoundary(layoutPtr, raidAddress);
               stripeEndAddress = RF_MIN(endAddress, stripeRealEndAddress);
               asm_p->raidAddress = raidAddress;
               asm_p->endRaidAddress = stripeEndAddress;

               /* map each stripe unit in the stripe */
               pda_p = NULL;

               /* Raid addr of start of portion of access that is
                  within this stripe */
               startAddrWithinStripe = raidAddress;

               for (; raidAddress < stripeEndAddress;) {
                       RF_ASSERT(pdaList);
                       t_pda = pdaList;
                       pdaList = pdaList->next;
                       memset(t_pda, 0, sizeof(*t_pda));
                       if (!pda_p)
                               asm_p->physInfo = pda_p = t_pda;
                       else {
                               pda_p->next = t_pda;
                               pda_p = pda_p->next;
                       }

                       pda_p->type = RF_PDA_TYPE_DATA;
                       (layoutPtr->map->MapSector) (raidPtr, raidAddress,
                                                    &(pda_p->col),
                                                    &(pda_p->startSector),
                                                    remap);

                       /* mark any failures we find.  failedPDA is
                        * don't-care if there is more than one
                        * failure */

                       /* the RAID address corresponding to this
                          physical diskaddress */
                       pda_p->raidAddress = raidAddress;
                       nextStripeUnitAddress = rf_RaidAddressOfNextStripeUnitBoundary(layoutPtr, raidAddress);
                       pda_p->numSector = RF_MIN(endAddress, nextStripeUnitAddress) - raidAddress;
                       RF_ASSERT(pda_p->numSector != 0);
                       rf_ASMCheckStatus(raidPtr, pda_p, asm_p, disks, 0);
                       pda_p->bufPtr = (char *)buffer + rf_RaidAddressToByte(raidPtr, (raidAddress - startAddress));
                       asm_p->totalSectorsAccessed += pda_p->numSector;
                       asm_p->numStripeUnitsAccessed++;

                       raidAddress = RF_MIN(endAddress, nextStripeUnitAddress);
               }

               /* Map the parity. At this stage, the startSector and
                * numSector fields for the parity unit are always set
                * to indicate the entire parity unit. We may modify
                * this after mapping the data portion. */
               switch (faultsTolerated) {
               case 0:
                       break;
               case 1: /* single fault tolerant */
                       RF_ASSERT(pdaList);
                       t_pda = pdaList;
                       pdaList = pdaList->next;
                       memset(t_pda, 0, sizeof(*t_pda));
                       pda_p = asm_p->parityInfo = t_pda;
                       pda_p->type = RF_PDA_TYPE_PARITY;
                       (layoutPtr->map->MapParity) (raidPtr, rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, startAddrWithinStripe),
                           &(pda_p->col), &(pda_p->startSector), remap);
                       pda_p->numSector = layoutPtr->sectorsPerStripeUnit;
                       /* raidAddr may be needed to find unit to redirect to */
                       pda_p->raidAddress = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, startAddrWithinStripe);
                       rf_ASMCheckStatus(raidPtr, pda_p, asm_p, disks, 1);
                       rf_ASMParityAdjust(raidPtr, asm_p->parityInfo, startAddrWithinStripe, endAddress, layoutPtr, asm_p);

                       break;
#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)
               case 2: /* two fault tolerant */
                       RF_ASSERT(pdaList && pdaList->next);
                       t_pda = pdaList;
                       pdaList = pdaList->next;
                       memset(t_pda, 0, sizeof(*t_pda));
                       pda_p = asm_p->parityInfo = t_pda;
                       pda_p->type = RF_PDA_TYPE_PARITY;
                       t_pda = pdaList;
                       pdaList = pdaList->next;
                       memset(t_pda, 0, sizeof(*t_pda));
                       pda_q = asm_p->qInfo = t_pda;
                       pda_q->type = RF_PDA_TYPE_Q;
                       (layoutPtr->map->MapParity) (raidPtr, rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, startAddrWithinStripe),
                           &(pda_p->col), &(pda_p->startSector), remap);
                       (layoutPtr->map->MapQ) (raidPtr, rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, startAddrWithinStripe),
                           &(pda_q->col), &(pda_q->startSector), remap);
                       pda_q->numSector = pda_p->numSector = layoutPtr->sectorsPerStripeUnit;
                       /* raidAddr may be needed to find unit to redirect to */
                       pda_p->raidAddress = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, startAddrWithinStripe);
                       pda_q->raidAddress = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, startAddrWithinStripe);
                       /* failure mode stuff */
                       rf_ASMCheckStatus(raidPtr, pda_p, asm_p, disks, 1);
                       rf_ASMCheckStatus(raidPtr, pda_q, asm_p, disks, 1);
                       rf_ASMParityAdjust(raidPtr, asm_p->parityInfo, startAddrWithinStripe, endAddress, layoutPtr, asm_p);
                       rf_ASMParityAdjust(raidPtr, asm_p->qInfo, startAddrWithinStripe, endAddress, layoutPtr, asm_p);
                       break;
#endif
               }
       }
       RF_ASSERT(asmList == NULL && pdaList == NULL);
       /* make the header structure */
       asm_hdr = rf_AllocAccessStripeMapHeader(raidPtr);
       RF_ASSERT(numStripes == totStripes);
       asm_hdr->numStripes = numStripes;
       asm_hdr->stripeMap = asm_list;

#if RF_DEBUG_MAP
       if (rf_mapDebug)
               rf_PrintAccessStripeMap(asm_hdr);
#endif
       return (asm_hdr);
}

/***************************************************************************
* This routine walks through an ASM list and marks the PDAs that have
* failed.  It's called only when a disk failure causes an in-flight
* DAG to fail.  The parity may consist of two components, but we want
* to use only one failedPDA pointer.  Thus we set failedPDA to point
* to the first parity component, and rely on the rest of the code to
* do the right thing with this.
***************************************************************************/

void
rf_MarkFailuresInASMList(RF_Raid_t *raidPtr,
                        RF_AccessStripeMapHeader_t *asm_h)
{
       RF_RaidDisk_t *disks = raidPtr->Disks;
       RF_AccessStripeMap_t *asmap;
       RF_PhysDiskAddr_t *pda;

       for (asmap = asm_h->stripeMap; asmap; asmap = asmap->next) {
               asmap->numDataFailed = 0;
               asmap->numParityFailed = 0;
               asmap->numQFailed = 0;
               asmap->numFailedPDAs = 0;
               memset(asmap->failedPDAs, 0,
                   RF_MAX_FAILED_PDA * sizeof(*asmap->failedPDAs));
               for (pda = asmap->physInfo; pda; pda = pda->next) {
                       if (RF_DEAD_DISK(disks[pda->col].status)) {
                               asmap->numDataFailed++;
                               asmap->failedPDAs[asmap->numFailedPDAs] = pda;
                               asmap->numFailedPDAs++;
                       }
               }
               pda = asmap->parityInfo;
               if (pda && RF_DEAD_DISK(disks[pda->col].status)) {
                       asmap->numParityFailed++;
                       asmap->failedPDAs[asmap->numFailedPDAs] = pda;
                       asmap->numFailedPDAs++;
               }
               pda = asmap->qInfo;
               if (pda && RF_DEAD_DISK(disks[pda->col].status)) {
                       asmap->numQFailed++;
                       asmap->failedPDAs[asmap->numFailedPDAs] = pda;
                       asmap->numFailedPDAs++;
               }
       }
}

/***************************************************************************
*
* routines to allocate and free list elements.  All allocation
* routines zero the structure before returning it.
*
* FreePhysDiskAddr is static.  It should never be called directly,
* because FreeAccessStripeMap takes care of freeing the PhysDiskAddr
* list.
*
***************************************************************************/

#define RF_MAX_FREE_ASMHDR 128
#define RF_MIN_FREE_ASMHDR  32

#define RF_MAX_FREE_ASM 192
#define RF_MIN_FREE_ASM  64

#define RF_MAX_FREE_PDA 192
#define RF_MIN_FREE_PDA  64

#define RF_MAX_FREE_ASMHLE 64
#define RF_MIN_FREE_ASMHLE 16

#define RF_MAX_FREE_FSS 128
#define RF_MIN_FREE_FSS  32

#define RF_MAX_FREE_VFPLE 128
#define RF_MIN_FREE_VFPLE  32

#define RF_MAX_FREE_VPLE 128
#define RF_MIN_FREE_VPLE  32


/* called at shutdown time.  So far, all that is necessary is to
  release all the free lists */
static void rf_ShutdownMapModule(void *);
static void
rf_ShutdownMapModule(void *arg)
{
       RF_Raid_t *raidPtr;

       raidPtr = (RF_Raid_t *) arg;

       pool_destroy(&raidPtr->pools.asm_hdr);
       pool_destroy(&raidPtr->pools.asmap);
       pool_destroy(&raidPtr->pools.asmhle);
       pool_destroy(&raidPtr->pools.pda);
       pool_destroy(&raidPtr->pools.fss);
       pool_destroy(&raidPtr->pools.vfple);
       pool_destroy(&raidPtr->pools.vple);
}

int
rf_ConfigureMapModule(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr,
                     RF_Config_t *cfgPtr)
{

       rf_pool_init(raidPtr, raidPtr->poolNames.asm_hdr, &raidPtr->pools.asm_hdr, sizeof(RF_AccessStripeMapHeader_t),
                    "asmhdr", RF_MIN_FREE_ASMHDR, RF_MAX_FREE_ASMHDR);
       rf_pool_init(raidPtr, raidPtr->poolNames.asmap, &raidPtr->pools.asmap, sizeof(RF_AccessStripeMap_t),
                    "asmap", RF_MIN_FREE_ASM, RF_MAX_FREE_ASM);
       rf_pool_init(raidPtr, raidPtr->poolNames.asmhle, &raidPtr->pools.asmhle, sizeof(RF_ASMHeaderListElem_t),
                    "asmhle", RF_MIN_FREE_ASMHLE, RF_MAX_FREE_ASMHLE);
       rf_pool_init(raidPtr, raidPtr->poolNames.pda, &raidPtr->pools.pda, sizeof(RF_PhysDiskAddr_t),
                    "pda", RF_MIN_FREE_PDA, RF_MAX_FREE_PDA);
       rf_pool_init(raidPtr, raidPtr->poolNames.fss, &raidPtr->pools.fss, sizeof(RF_FailedStripe_t),
                    "fss", RF_MIN_FREE_FSS, RF_MAX_FREE_FSS);
       rf_pool_init(raidPtr, raidPtr->poolNames.vfple, &raidPtr->pools.vfple, sizeof(RF_VoidFunctionPointerListElem_t),
                    "vfple", RF_MIN_FREE_VFPLE, RF_MAX_FREE_VFPLE);
       rf_pool_init(raidPtr, raidPtr->poolNames.vple, &raidPtr->pools.vple, sizeof(RF_VoidPointerListElem_t),
                    "vple", RF_MIN_FREE_VPLE, RF_MAX_FREE_VPLE);
       rf_ShutdownCreate(listp, rf_ShutdownMapModule, raidPtr);

       return (0);
}

RF_AccessStripeMapHeader_t *
rf_AllocAccessStripeMapHeader(RF_Raid_t *raidPtr)
{
       return pool_get(&raidPtr->pools.asm_hdr, PR_WAITOK | PR_ZERO);
}

void
rf_FreeAccessStripeMapHeader(RF_Raid_t *raidPtr, RF_AccessStripeMapHeader_t *p)
{
       pool_put(&raidPtr->pools.asm_hdr, p);
}


RF_VoidFunctionPointerListElem_t *
rf_AllocVFPListElem(RF_Raid_t *raidPtr)
{
       return pool_get(&raidPtr->pools.vfple, PR_WAITOK | PR_ZERO);
}

void
rf_FreeVFPListElem(RF_Raid_t *raidPtr, RF_VoidFunctionPointerListElem_t *p)
{

       pool_put(&raidPtr->pools.vfple, p);
}


RF_VoidPointerListElem_t *
rf_AllocVPListElem(RF_Raid_t *raidPtr)
{
       return pool_get(&raidPtr->pools.vple, PR_WAITOK | PR_ZERO);
}

void
rf_FreeVPListElem(RF_Raid_t *raidPtr, RF_VoidPointerListElem_t *p)
{

       pool_put(&raidPtr->pools.vple, p);
}

RF_ASMHeaderListElem_t *
rf_AllocASMHeaderListElem(RF_Raid_t *raidPtr)
{
       return pool_get(&raidPtr->pools.asmhle, PR_WAITOK | PR_ZERO);
}

void
rf_FreeASMHeaderListElem(RF_Raid_t *raidPtr, RF_ASMHeaderListElem_t *p)
{

       pool_put(&raidPtr->pools.asmhle, p);
}

RF_FailedStripe_t *
rf_AllocFailedStripeStruct(RF_Raid_t *raidPtr)
{
       return pool_get(&raidPtr->pools.fss, PR_WAITOK | PR_ZERO);
}

void
rf_FreeFailedStripeStruct(RF_Raid_t *raidPtr, RF_FailedStripe_t *p)
{
       pool_put(&raidPtr->pools.fss, p);
}





RF_PhysDiskAddr_t *
rf_AllocPhysDiskAddr(RF_Raid_t *raidPtr)
{
       return pool_get(&raidPtr->pools.pda, PR_WAITOK | PR_ZERO);
}
/* allocates a list of PDAs, locking the free list only once when we
* have to call calloc, we do it one component at a time to simplify
* the process of freeing the list at program shutdown.  This should
* not be much of a performance hit, because it should be very
* infrequently executed.  */
RF_PhysDiskAddr_t *
rf_AllocPDAList(RF_Raid_t *raidPtr, int count)
{
       RF_PhysDiskAddr_t *p, *prev;
       int i;

       p = NULL;
       prev = NULL;
       for (i = 0; i < count; i++) {
               p = pool_get(&raidPtr->pools.pda, PR_WAITOK);
               p->next = prev;
               prev = p;
       }

       return (p);
}

void
rf_FreePhysDiskAddr(RF_Raid_t *raidPtr, RF_PhysDiskAddr_t *p)
{
       pool_put(&raidPtr->pools.pda, p);
}

static void
rf_FreePDAList(RF_Raid_t *raidPtr, RF_PhysDiskAddr_t *pda_list)
{
       RF_PhysDiskAddr_t *p, *tmp;

       p=pda_list;
       while (p) {
               tmp = p->next;
               pool_put(&raidPtr->pools.pda, p);
               p = tmp;
       }
}

/* this is essentially identical to AllocPDAList.  I should combine
* the two.  when we have to call calloc, we do it one component at a
* time to simplify the process of freeing the list at program
* shutdown.  This should not be much of a performance hit, because it
* should be very infrequently executed.  */
RF_AccessStripeMap_t *
rf_AllocASMList(RF_Raid_t *raidPtr, int count)
{
       RF_AccessStripeMap_t *p, *prev;
       int i;

       p = NULL;
       prev = NULL;
       for (i = 0; i < count; i++) {
               p = pool_get(&raidPtr->pools.asmap, PR_WAITOK);
               p->next = prev;
               prev = p;
       }
       return (p);
}

static void
rf_FreeASMList(RF_Raid_t *raidPtr, RF_AccessStripeMap_t *asm_list)
{
       RF_AccessStripeMap_t *p, *tmp;

       p=asm_list;
       while (p) {
               tmp = p->next;
               pool_put(&raidPtr->pools.asmap, p);
               p = tmp;
       }
}

void
rf_FreeAccessStripeMap(RF_Raid_t *raidPtr, RF_AccessStripeMapHeader_t *hdr)
{
       RF_AccessStripeMap_t *p;
       RF_PhysDiskAddr_t *pdp, *trailer, *pdaList = NULL, *pdaEnd = NULL;
       int     count = 0, t;

       for (p = hdr->stripeMap; p; p = p->next) {

               /* link the 3 pda lists into the accumulating pda list */

               if (!pdaList)
                       pdaList = p->qInfo;
               else
                       pdaEnd->next = p->qInfo;
               for (trailer = NULL, pdp = p->qInfo; pdp;) {
                       trailer = pdp;
                       pdp = pdp->next;
                       count++;
               }
               if (trailer)
                       pdaEnd = trailer;

               if (!pdaList)
                       pdaList = p->parityInfo;
               else
                       pdaEnd->next = p->parityInfo;
               for (trailer = NULL, pdp = p->parityInfo; pdp;) {
                       trailer = pdp;
                       pdp = pdp->next;
                       count++;
               }
               if (trailer)
                       pdaEnd = trailer;

               if (!pdaList)
                       pdaList = p->physInfo;
               else
                       pdaEnd->next = p->physInfo;
               for (trailer = NULL, pdp = p->physInfo; pdp;) {
                       trailer = pdp;
                       pdp = pdp->next;
                       count++;
               }
               if (trailer)
                       pdaEnd = trailer;
       }

       /* debug only */
       for (t = 0, pdp = pdaList; pdp; pdp = pdp->next)
               t++;
       RF_ASSERT(t == count);

       if (pdaList)
               rf_FreePDAList(raidPtr, pdaList);
       rf_FreeASMList(raidPtr, hdr->stripeMap);
       rf_FreeAccessStripeMapHeader(raidPtr, hdr);
}
/* We can't use the large write optimization if there are any failures
* in the stripe.  In the declustered layout, there is no way to
* immediately determine what disks constitute a stripe, so we
* actually have to hunt through the stripe looking for failures.  The
* reason we map the parity instead of just using asm->parityInfo->col
* is because the latter may have been already redirected to a spare
* drive, which would mess up the computation of the stripe offset.
*
* ASSUMES AT MOST ONE FAILURE IN THE STRIPE.  */
int
rf_CheckStripeForFailures(RF_Raid_t *raidPtr, RF_AccessStripeMap_t *asmap)
{
       RF_RowCol_t tcol, pcol, *diskids, i;
       RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
       RF_StripeCount_t stripeOffset;
       int     numFailures;
       RF_RaidAddr_t sosAddr;
       RF_SectorNum_t diskOffset, poffset;

       /* quick out in the fault-free case.  */
       rf_lock_mutex2(raidPtr->mutex);
       numFailures = raidPtr->numFailures;
       rf_unlock_mutex2(raidPtr->mutex);
       if (numFailures == 0)
               return (0);

       sosAddr = rf_RaidAddressOfPrevStripeBoundary(layoutPtr,
                                                    asmap->raidAddress);
       (layoutPtr->map->IdentifyStripe) (raidPtr, asmap->raidAddress,
                                         &diskids);
       (layoutPtr->map->MapParity) (raidPtr, asmap->raidAddress,
                                    &pcol, &poffset, 0);       /* get pcol */

       /* this need not be true if we've redirected the access to a
        * spare in another row RF_ASSERT(row == testrow); */
       stripeOffset = 0;
       for (i = 0; i < layoutPtr->numDataCol + layoutPtr->numParityCol; i++) {
               if (diskids[i] != pcol) {
                       if (RF_DEAD_DISK(raidPtr->Disks[diskids[i]].status)) {
                               if (raidPtr->status != rf_rs_reconstructing)
                                       return (1);
                               RF_ASSERT(raidPtr->reconControl->fcol == diskids[i]);
                               layoutPtr->map->MapSector(raidPtr,
                                   sosAddr + stripeOffset * layoutPtr->sectorsPerStripeUnit,
                                   &tcol, &diskOffset, 0);
                               RF_ASSERT(tcol == diskids[i]);
                               if (!rf_CheckRUReconstructed(raidPtr->reconControl->reconMap, diskOffset))
                                       return (1);
                               asmap->flags |= RF_ASM_REDIR_LARGE_WRITE;
                               return (0);
                       }
                       stripeOffset++;
               }
       }
       return (0);
}
#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0) || (RF_INCLUDE_EVENODD >0)
/*
  return the number of failed data units in the stripe.
*/

int
rf_NumFailedDataUnitsInStripe(RF_Raid_t *raidPtr, RF_AccessStripeMap_t *asmap)
{
       RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
       RF_RowCol_t tcol, i;
       RF_SectorNum_t diskOffset;
       RF_RaidAddr_t sosAddr;
       int     numFailures;

       /* quick out in the fault-free case.  */
       rf_lock_mutex2(raidPtr->mutex);
       numFailures = raidPtr->numFailures;
       rf_unlock_mutex2(raidPtr->mutex);
       if (numFailures == 0)
               return (0);
       numFailures = 0;

       sosAddr = rf_RaidAddressOfPrevStripeBoundary(layoutPtr,
                                                    asmap->raidAddress);
       for (i = 0; i < layoutPtr->numDataCol; i++) {
               (layoutPtr->map->MapSector) (raidPtr, sosAddr + i * layoutPtr->sectorsPerStripeUnit,
                   &tcol, &diskOffset, 0);
               if (RF_DEAD_DISK(raidPtr->Disks[tcol].status))
                       numFailures++;
       }

       return numFailures;
}
#endif

/****************************************************************************
*
* debug routines
*
***************************************************************************/
#if RF_DEBUG_MAP
void
rf_PrintAccessStripeMap(RF_AccessStripeMapHeader_t *asm_h)
{
       rf_PrintFullAccessStripeMap(asm_h, 0);
}
#endif

/* prbuf - flag to print buffer pointers */
void
rf_PrintFullAccessStripeMap(RF_AccessStripeMapHeader_t *asm_h, int prbuf)
{
       int     i;
       RF_AccessStripeMap_t *asmap = asm_h->stripeMap;
       RF_PhysDiskAddr_t *p;
       printf("%d stripes total\n", (int) asm_h->numStripes);
       for (; asmap; asmap = asmap->next) {
               /* printf("Num failures: %d\n",asmap->numDataFailed); */
               /* printf("Num sectors:
                * %d\n",(int)asmap->totalSectorsAccessed); */
               printf("Stripe %d (%d sectors), failures: %d data, %d parity: ",
                   (int) asmap->stripeID,
                   (int) asmap->totalSectorsAccessed,
                   (int) asmap->numDataFailed,
                   (int) asmap->numParityFailed);
               if (asmap->parityInfo) {
                       printf("Parity [c%d s%d-%d", asmap->parityInfo->col,
                           (int) asmap->parityInfo->startSector,
                           (int) (asmap->parityInfo->startSector +
                               asmap->parityInfo->numSector - 1));
                       if (prbuf)
                               printf(" b0x%lx", (unsigned long) asmap->parityInfo->bufPtr);
                       if (asmap->parityInfo->next) {
                               printf(", c%d s%d-%d", asmap->parityInfo->next->col,
                                   (int) asmap->parityInfo->next->startSector,
                                   (int) (asmap->parityInfo->next->startSector +
                                       asmap->parityInfo->next->numSector - 1));
                               if (prbuf)
                                       printf(" b0x%lx", (unsigned long) asmap->parityInfo->next->bufPtr);
                               RF_ASSERT(asmap->parityInfo->next->next == NULL);
                       }
                       printf("]\n\t");
               }
               for (i = 0, p = asmap->physInfo; p; p = p->next, i++) {
                       printf("SU c%d s%d-%d ", p->col, (int) p->startSector,
                           (int) (p->startSector + p->numSector - 1));
                       if (prbuf)
                               printf("b0x%lx ", (unsigned long) p->bufPtr);
                       if (i && !(i & 1))
                               printf("\n\t");
               }
               printf("\n");
               p = asm_h->stripeMap->failedPDAs[0];
               if (asm_h->stripeMap->numDataFailed + asm_h->stripeMap->numParityFailed > 1)
                       printf("[multiple failures]\n");
               else
                       if (asm_h->stripeMap->numDataFailed + asm_h->stripeMap->numParityFailed > 0)
                               printf("\t[Failed PDA: c%d s%d-%d]\n", p->col,
                                   (int) p->startSector, (int) (p->startSector + p->numSector - 1));
       }
}

#if RF_MAP_DEBUG
void
rf_PrintRaidAddressInfo(RF_Raid_t *raidPtr, RF_RaidAddr_t raidAddr,
                       RF_SectorCount_t numBlocks)
{
       RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
       RF_RaidAddr_t ra, sosAddr = rf_RaidAddressOfPrevStripeBoundary(layoutPtr, raidAddr);

       printf("Raid addrs of SU boundaries from start of stripe to end of access:\n\t");
       for (ra = sosAddr; ra <= raidAddr + numBlocks; ra += layoutPtr->sectorsPerStripeUnit) {
               printf("%d (0x%x), ", (int) ra, (int) ra);
       }
       printf("\n");
       printf("Offset into stripe unit: %d (0x%x)\n",
           (int) (raidAddr % layoutPtr->sectorsPerStripeUnit),
           (int) (raidAddr % layoutPtr->sectorsPerStripeUnit));
}
#endif
/* given a parity descriptor and the starting address within a stripe,
* range restrict the parity descriptor to touch only the correct
* stuff.  */
void
rf_ASMParityAdjust(RF_Raid_t *raidPtr,
                  RF_PhysDiskAddr_t *toAdjust,
                  RF_StripeNum_t startAddrWithinStripe,
                  RF_SectorNum_t endAddress,
                  RF_RaidLayout_t *layoutPtr,
                  RF_AccessStripeMap_t *asm_p)
{
       RF_PhysDiskAddr_t *new_pda;

       /* when we're accessing only a portion of one stripe unit, we
        * want the parity descriptor to identify only the chunk of
        * parity associated with the data.  When the access spans
        * exactly one stripe unit boundary and is less than a stripe
        * unit in size, it uses two disjoint regions of the parity
        * unit.  When an access spans more than one stripe unit
        * boundary, it uses all of the parity unit.
        *
        * To better handle the case where stripe units are small, we
        * may eventually want to change the 2nd case so that if the
        * SU size is below some threshold, we just read/write the
        * whole thing instead of breaking it up into two accesses. */
       if (asm_p->numStripeUnitsAccessed == 1) {
               int     x = (startAddrWithinStripe % layoutPtr->sectorsPerStripeUnit);
               toAdjust->startSector += x;
               toAdjust->raidAddress += x;
               toAdjust->numSector = asm_p->physInfo->numSector;
               RF_ASSERT(toAdjust->numSector != 0);
       } else
               if (asm_p->numStripeUnitsAccessed == 2 && asm_p->totalSectorsAccessed < layoutPtr->sectorsPerStripeUnit) {
                       int     x = (startAddrWithinStripe % layoutPtr->sectorsPerStripeUnit);

                       /* create a second pda and copy the parity map info
                        * into it */
                       RF_ASSERT(toAdjust->next == NULL);
                       /* the following will get freed in rf_FreeAccessStripeMap() via
                          rf_FreePDAList() */
                       new_pda = toAdjust->next = rf_AllocPhysDiskAddr(raidPtr);
                       *new_pda = *toAdjust;   /* structure assignment */
                       new_pda->next = NULL;

                       /* adjust the start sector & number of blocks for the
                        * first parity pda */
                       toAdjust->startSector += x;
                       toAdjust->raidAddress += x;
                       toAdjust->numSector = rf_RaidAddressOfNextStripeUnitBoundary(layoutPtr, startAddrWithinStripe) - startAddrWithinStripe;
                       RF_ASSERT(toAdjust->numSector != 0);

                       /* adjust the second pda */
                       new_pda->numSector = endAddress - rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, endAddress);
                       /* new_pda->raidAddress =
                        * rf_RaidAddressOfNextStripeUnitBoundary(layoutPtr,
                        * toAdjust->raidAddress); */
                       RF_ASSERT(new_pda->numSector != 0);
               }
}

/* Check if a disk has been spared or failed. If spared, redirect the
* I/O.  If it has been failed, record it in the asm pointer.  Fifth
* arg is whether data or parity.  */
void
rf_ASMCheckStatus(RF_Raid_t *raidPtr, RF_PhysDiskAddr_t *pda_p,
                 RF_AccessStripeMap_t *asm_p, RF_RaidDisk_t *disks,
                 int parity)
{
       RF_DiskStatus_t dstatus;
       RF_RowCol_t fcol;

       dstatus = disks[pda_p->col].status;

       if (dstatus == rf_ds_spared) {
               /* if the disk has been spared, redirect access to the spare */
               fcol = pda_p->col;
               pda_p->col = disks[fcol].spareCol;
       } else
               if (dstatus == rf_ds_dist_spared) {
                       /* ditto if disk has been spared to dist spare space */
#if RF_DEBUG_MAP
                       RF_RowCol_t oc = pda_p->col;
                       RF_SectorNum_t oo = pda_p->startSector;
#endif
                       if (pda_p->type == RF_PDA_TYPE_DATA)
                               raidPtr->Layout.map->MapSector(raidPtr, pda_p->raidAddress, &pda_p->col, &pda_p->startSector, RF_REMAP);
                       else
                               raidPtr->Layout.map->MapParity(raidPtr, pda_p->raidAddress, &pda_p->col, &pda_p->startSector, RF_REMAP);

#if RF_DEBUG_MAP
                       if (rf_mapDebug) {
                               printf("Redirected c %d o %d -> c %d o %d\n", oc, (int) oo,
                                   pda_p->col, (int) pda_p->startSector);
                       }
#endif
               } else
                       if (RF_DEAD_DISK(dstatus)) {
                               /* if the disk is inaccessible, mark the
                                * failure */
                               if (parity)
                                       asm_p->numParityFailed++;
                               else {
                                       asm_p->numDataFailed++;
                               }
                               asm_p->failedPDAs[asm_p->numFailedPDAs] = pda_p;
                               asm_p->numFailedPDAs++;
#if 0
                               switch (asm_p->numParityFailed + asm_p->numDataFailed) {
                               case 1:
                                       asm_p->failedPDAs[0] = pda_p;
                                       break;
                               case 2:
                                       asm_p->failedPDAs[1] = pda_p;
                               default:
                                       break;
                               }
#endif
                       }
       /* the redirected access should never span a stripe unit boundary */
       RF_ASSERT(rf_RaidAddressToStripeUnitID(&raidPtr->Layout, pda_p->raidAddress) ==
           rf_RaidAddressToStripeUnitID(&raidPtr->Layout, pda_p->raidAddress + pda_p->numSector - 1));
       RF_ASSERT(pda_p->col != -1);
}