/* $OpenBSD: rf_raid5.c,v 1.4 2002/12/16 07:01:04 tdeval Exp $ */ /* $NetBSD: rf_raid5.c,v 1.4 2000/01/08 22:57:30 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 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 "rf_types.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. */ RF_MallocAndAdd(info, sizeof(RF_Raid5ConfigInfo_t), (RF_Raid5ConfigInfo_t *), raidPtr->cleanupList); if (info == NULL) return (ENOMEM); layoutPtr->layoutSpecificInfo = (void *) info; RF_ASSERT(raidPtr->numRow == 1); /* * 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->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit << raidPtr->logBytesPerSector; 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(__OpenBSD__) && !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 *row, RF_RowCol_t *col, RF_SectorNum_t *diskSector, int remap) { RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit; *row = 0; *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 *row, RF_RowCol_t *col, RF_SectorNum_t *diskSector, int remap) { RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit; *row = 0; *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_RowCol_t *outRow) { RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr); RF_Raid5ConfigInfo_t *info = (RF_Raid5ConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo; *outRow = 0; *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 frow, fcol; RF_RowStatus_t rstat; int prior_recon; 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"); /* *infoFunc = */ *createFunc = NULL; return; } else 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]; frow = failedPDA->row; fcol = failedPDA->col; rstat = raidPtr->status[failedPDA->row]; prior_recon = (rstat == rf_rs_reconfigured) || ( (rstat == rf_rs_reconstructing) ? rf_CheckRUReconstructed(raidPtr ->reconControl[frow]->reconMap, failedPDA->startSector) : 0); if (prior_recon) { RF_RowCol_t or = failedPDA->row; RF_RowCol_t oc = failedPDA->col; RF_SectorNum_t oo = failedPDA->startSector; 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->row, &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->row = failedPDA->row; p->col = failedPDA->col; /* * Cheating: * startSector is not * really a RAID * address. */ p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary( layoutPtr, failedPDA->startSector) + SUoffs; } } else if (asmap->parityInfo->next && failedPDA == asmap->parityInfo->next) { /* * Should never happen. */ RF_ASSERT(0); } else { /* Data has failed. */ (layoutPtr->map ->MapSector) (raidPtr, failedPDA->raidAddress, &failedPDA->row, &failedPDA->col, &failedPDA->startSector, RF_REMAP); } } else { /* Redirect to dedicated spare space. */ failedPDA->row = raidPtr->Disks[frow][fcol].spareRow; failedPDA->col = raidPtr->Disks[frow][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->row = failedPDA->row; failedPDA->next->col = failedPDA->col; } else { if (failedPDA == asmap->parityInfo ->next) { /* * Paranoid: * Should never * occur. */ asmap ->parityInfo ->row = failedPDA->row; asmap ->parityInfo ->col = failedPDA->col; } } } } RF_ASSERT(failedPDA->col != -1); if (rf_dagDebug || rf_mapDebug) { printf("raid%d: Redirected type '%c'" " r %d c %d o %ld -> r %d c %d" " o %ld\n", raidPtr->raidid, type, or, oc, (long) oo, failedPDA->row, failedPDA->col, (long) failedPDA->startSector); } 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->numSector != layoutPtr->sectorsPerStripeUnit) *createFunc = NULL; else *createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG; } } }