321 lines
10 KiB
C
321 lines
10 KiB
C
/* $NetBSD: rf_raid5.c,v 1.3 1999/02/05 00:06:16 oster Exp $ */
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/*
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* Copyright (c) 1995 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Author: Mark Holland
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/******************************************************************************
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*
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* rf_raid5.c -- implements RAID Level 5
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*
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*****************************************************************************/
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#include "rf_types.h"
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#include "rf_raid.h"
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#include "rf_raid5.h"
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#include "rf_dag.h"
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#include "rf_dagffrd.h"
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#include "rf_dagffwr.h"
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#include "rf_dagdegrd.h"
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#include "rf_dagdegwr.h"
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#include "rf_dagutils.h"
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#include "rf_threadid.h"
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#include "rf_general.h"
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#include "rf_map.h"
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#include "rf_utils.h"
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typedef struct RF_Raid5ConfigInfo_s {
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RF_RowCol_t **stripeIdentifier; /* filled in at config time and used
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* by IdentifyStripe */
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} RF_Raid5ConfigInfo_t;
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int
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rf_ConfigureRAID5(
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RF_ShutdownList_t ** listp,
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RF_Raid_t * raidPtr,
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RF_Config_t * cfgPtr)
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{
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RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
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RF_Raid5ConfigInfo_t *info;
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RF_RowCol_t i, j, startdisk;
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/* create a RAID level 5 configuration structure */
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RF_MallocAndAdd(info, sizeof(RF_Raid5ConfigInfo_t), (RF_Raid5ConfigInfo_t *), raidPtr->cleanupList);
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if (info == NULL)
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return (ENOMEM);
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layoutPtr->layoutSpecificInfo = (void *) info;
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RF_ASSERT(raidPtr->numRow == 1);
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/* the stripe identifier must identify the disks in each stripe, IN
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* THE ORDER THAT THEY APPEAR IN THE STRIPE. */
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info->stripeIdentifier = rf_make_2d_array(raidPtr->numCol, raidPtr->numCol, raidPtr->cleanupList);
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if (info->stripeIdentifier == NULL)
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return (ENOMEM);
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startdisk = 0;
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for (i = 0; i < raidPtr->numCol; i++) {
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for (j = 0; j < raidPtr->numCol; j++) {
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info->stripeIdentifier[i][j] = (startdisk + j) % raidPtr->numCol;
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}
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if ((--startdisk) < 0)
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startdisk = raidPtr->numCol - 1;
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}
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/* fill in the remaining layout parameters */
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layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
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layoutPtr->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit << raidPtr->logBytesPerSector;
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layoutPtr->numDataCol = raidPtr->numCol - 1;
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layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
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layoutPtr->numParityCol = 1;
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layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;
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raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
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return (0);
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}
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int
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rf_GetDefaultNumFloatingReconBuffersRAID5(RF_Raid_t * raidPtr)
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{
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return (20);
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}
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RF_HeadSepLimit_t
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rf_GetDefaultHeadSepLimitRAID5(RF_Raid_t * raidPtr)
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{
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return (10);
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}
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#if !defined(__NetBSD__) && !defined(_KERNEL)
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/* not currently used */
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int
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rf_ShutdownRAID5(RF_Raid_t * raidPtr)
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{
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return (0);
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}
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#endif
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void
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rf_MapSectorRAID5(
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RF_Raid_t * raidPtr,
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RF_RaidAddr_t raidSector,
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RF_RowCol_t * row,
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RF_RowCol_t * col,
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RF_SectorNum_t * diskSector,
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int remap)
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{
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RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
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*row = 0;
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*col = (SUID % raidPtr->numCol);
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*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
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(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
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}
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void
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rf_MapParityRAID5(
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RF_Raid_t * raidPtr,
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RF_RaidAddr_t raidSector,
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RF_RowCol_t * row,
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RF_RowCol_t * col,
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RF_SectorNum_t * diskSector,
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int remap)
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{
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RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
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*row = 0;
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*col = raidPtr->Layout.numDataCol - (SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
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*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
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(raidSector % raidPtr->Layout.sectorsPerStripeUnit);
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}
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void
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rf_IdentifyStripeRAID5(
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RF_Raid_t * raidPtr,
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RF_RaidAddr_t addr,
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RF_RowCol_t ** diskids,
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RF_RowCol_t * outRow)
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{
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RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr);
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RF_Raid5ConfigInfo_t *info = (RF_Raid5ConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;
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*outRow = 0;
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*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
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}
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void
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rf_MapSIDToPSIDRAID5(
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RF_RaidLayout_t * layoutPtr,
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RF_StripeNum_t stripeID,
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RF_StripeNum_t * psID,
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RF_ReconUnitNum_t * which_ru)
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{
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*which_ru = 0;
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*psID = stripeID;
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}
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/* select an algorithm for performing an access. Returns two pointers,
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* one to a function that will return information about the DAG, and
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* another to a function that will create the dag.
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*/
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void
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rf_RaidFiveDagSelect(
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RF_Raid_t * raidPtr,
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RF_IoType_t type,
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RF_AccessStripeMap_t * asmap,
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RF_VoidFuncPtr * createFunc)
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{
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RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
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RF_PhysDiskAddr_t *failedPDA = NULL;
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RF_RowCol_t frow, fcol;
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RF_RowStatus_t rstat;
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int prior_recon;
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int tid;
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RF_ASSERT(RF_IO_IS_R_OR_W(type));
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if (asmap->numDataFailed + asmap->numParityFailed > 1) {
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RF_ERRORMSG("Multiple disks failed in a single group! Aborting I/O operation.\n");
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/* *infoFunc = */ *createFunc = NULL;
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return;
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} else
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if (asmap->numDataFailed + asmap->numParityFailed == 1) {
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/* if under recon & already reconstructed, redirect
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* the access to the spare drive and eliminate the
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* failure indication */
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failedPDA = asmap->failedPDAs[0];
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frow = failedPDA->row;
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fcol = failedPDA->col;
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rstat = raidPtr->status[failedPDA->row];
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prior_recon = (rstat == rf_rs_reconfigured) || (
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(rstat == rf_rs_reconstructing) ?
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rf_CheckRUReconstructed(raidPtr->reconControl[frow]->reconMap, failedPDA->startSector) : 0
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);
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if (prior_recon) {
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RF_RowCol_t or = failedPDA->row, oc = failedPDA->col;
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RF_SectorNum_t oo = failedPDA->startSector;
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if (layoutPtr->map->flags & RF_DISTRIBUTE_SPARE) { /* redirect to dist
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* spare space */
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if (failedPDA == asmap->parityInfo) {
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/* parity has failed */
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(layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
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&failedPDA->col, &failedPDA->startSector, RF_REMAP);
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if (asmap->parityInfo->next) { /* redir 2nd component,
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* if any */
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RF_PhysDiskAddr_t *p = asmap->parityInfo->next;
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RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit;
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p->row = failedPDA->row;
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p->col = failedPDA->col;
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p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) +
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SUoffs; /* cheating:
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* startSector is not
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* really a RAID address */
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}
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} else
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if (asmap->parityInfo->next && failedPDA == asmap->parityInfo->next) {
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RF_ASSERT(0); /* should not ever
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* happen */
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} else {
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/* data has failed */
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(layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress, &failedPDA->row,
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&failedPDA->col, &failedPDA->startSector, RF_REMAP);
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}
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} else { /* redirect to dedicated spare
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* space */
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failedPDA->row = raidPtr->Disks[frow][fcol].spareRow;
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failedPDA->col = raidPtr->Disks[frow][fcol].spareCol;
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/* the parity may have two distinct
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* components, both of which may need
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* to be redirected */
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if (asmap->parityInfo->next) {
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if (failedPDA == asmap->parityInfo) {
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failedPDA->next->row = failedPDA->row;
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failedPDA->next->col = failedPDA->col;
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} else
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if (failedPDA == asmap->parityInfo->next) { /* paranoid: should
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* never occur */
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asmap->parityInfo->row = failedPDA->row;
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asmap->parityInfo->col = failedPDA->col;
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}
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}
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}
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RF_ASSERT(failedPDA->col != -1);
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if (rf_dagDebug || rf_mapDebug) {
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rf_get_threadid(tid);
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printf("[%d] Redirected type '%c' r %d c %d o %ld -> r %d c %d o %ld\n",
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tid, type, or, oc, (long) oo, failedPDA->row, failedPDA->col,
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(long) failedPDA->startSector);
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}
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asmap->numDataFailed = asmap->numParityFailed = 0;
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}
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}
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/* all dags begin/end with block/unblock node therefore, hdrSucc &
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* termAnt counts should always be 1 also, these counts should not be
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* visible outside dag creation routines - manipulating the counts
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* here should be removed */
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if (type == RF_IO_TYPE_READ) {
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if (asmap->numDataFailed == 0)
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*createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG;
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else
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*createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG;
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} else {
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/* if mirroring, always use large writes. If the access
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* requires two distinct parity updates, always do a small
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* write. If the stripe contains a failure but the access
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* does not, do a small write. The first conditional
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* (numStripeUnitsAccessed <= numDataCol/2) uses a
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* less-than-or-equal rather than just a less-than because
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* when G is 3 or 4, numDataCol/2 is 1, and I want
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* single-stripe-unit updates to use just one disk. */
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if ((asmap->numDataFailed + asmap->numParityFailed) == 0) {
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if (rf_suppressLocksAndLargeWrites ||
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(((asmap->numStripeUnitsAccessed <= (layoutPtr->numDataCol / 2)) && (layoutPtr->numDataCol != 1)) ||
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(asmap->parityInfo->next != NULL) || rf_CheckStripeForFailures(raidPtr, asmap))) {
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*createFunc = (RF_VoidFuncPtr) rf_CreateSmallWriteDAG;
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} else
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*createFunc = (RF_VoidFuncPtr) rf_CreateLargeWriteDAG;
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} else {
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if (asmap->numParityFailed == 1)
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*createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG;
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else
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if (asmap->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit)
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*createFunc = NULL;
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else
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*createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG;
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}
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}
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}
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