206 lines
6.3 KiB
C
206 lines
6.3 KiB
C
/* $NetBSD: rf_pqdeg.c,v 1.3 1999/02/05 00:06:15 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: Daniel Stodolsky
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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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#include "rf_archs.h"
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#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)
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#include "rf_types.h"
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#include "rf_raid.h"
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#include "rf_dag.h"
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#include "rf_dagutils.h"
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#include "rf_dagfuncs.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_threadid.h"
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#include "rf_etimer.h"
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#include "rf_pqdeg.h"
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#include "rf_general.h"
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#include "rf_pqdegdags.h"
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#include "rf_pq.h"
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/*
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Degraded mode dag functions for P+Q calculations.
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The following nomenclature is used.
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PQ_<D><P><Q>_Create{Large,Small}<Write|Read>DAG
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where <D><P><Q> are single digits representing the number of failed
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data units <D> (0,1,2), parity units <P> (0,1), and Q units <Q>, effecting
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the I/O. The reads have only PQ_<D><P><Q>_CreateReadDAG variants, while
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the single fault writes have both large and small write versions. (Single fault
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PQ is equivalent to normal mode raid 5 in many aspects.
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Some versions degenerate into the same case, and are grouped together below.
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*/
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/* Reads, single failure
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we have parity, so we can do a raid 5
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reconstruct read.
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateReadDAG)
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{
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rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
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}
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/* Reads double failure */
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/*
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Q is lost, but not parity
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so we can a raid 5 reconstruct read.
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateReadDAG)
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{
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rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
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}
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/*
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parity is lost, so we need to
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do a reconstruct read and recompute
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the data with Q.
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateReadDAG)
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{
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RF_PhysDiskAddr_t *temp;
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/* swap P and Q pointers to fake out the DegradedReadDAG code */
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temp = asmap->parityInfo;
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asmap->parityInfo = asmap->qInfo;
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asmap->qInfo = temp;
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rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_qRecoveryFuncs);
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}
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/*
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Two data units are dead in this stripe, so we will need read
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both P and Q to reconstruct the data. Note that only
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one data unit we are reading may actually be missing.
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG)
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{
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rf_PQ_DoubleDegRead(raidPtr, asmap, dag_h, bp, flags, allocList);
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}
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG)
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{
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rf_CreateDoubleDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList);
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}
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/* Writes, single failure */
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG)
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{
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if (asmap->numStripeUnitsAccessed != 1 &&
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asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit)
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RF_PANIC();
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rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
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allocList, 2, (int (*) ()) rf_Degraded_100_PQFunc, RF_FALSE);
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}
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/* Dead P - act like a RAID 5 small write with parity = Q */
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateSmallWriteDAG)
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{
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RF_PhysDiskAddr_t *temp;
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/* swap P and Q pointers to fake out the DegradedReadDAG code */
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temp = asmap->parityInfo;
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asmap->parityInfo = asmap->qInfo;
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asmap->qInfo = temp;
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rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_qFuncs, NULL);
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}
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/* Dead Q - act like a RAID 5 small write */
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateSmallWriteDAG)
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{
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rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pFuncs, NULL);
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}
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/* Dead P - act like a RAID 5 large write but for Q */
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateLargeWriteDAG)
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{
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RF_PhysDiskAddr_t *temp;
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/* swap P and Q pointers to fake out the code */
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temp = asmap->parityInfo;
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asmap->parityInfo = asmap->qInfo;
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asmap->qInfo = temp;
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rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularQFunc, RF_FALSE);
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}
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/* Dead Q - act like a RAID 5 large write */
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateLargeWriteDAG)
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{
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rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularPFunc, RF_FALSE);
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}
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/*
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* writes, double failure
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*/
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/*
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* Lost P & Q - do a nonredundant write
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_011_CreateWriteDAG)
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{
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rf_CreateNonRedundantWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
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RF_IO_TYPE_WRITE);
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}
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/*
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In the two cases below,
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A nasty case arises when the write a (strict) portion of a failed stripe unit
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and parts of another su. For now, we do not support this.
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*/
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/*
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Lost Data and P - do a Q write.
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateWriteDAG)
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{
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RF_PhysDiskAddr_t *temp;
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if (asmap->numStripeUnitsAccessed != 1 &&
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asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit) {
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RF_PANIC();
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}
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/* swap P and Q to fake out parity code */
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temp = asmap->parityInfo;
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asmap->parityInfo = asmap->qInfo;
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asmap->qInfo = temp;
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rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
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allocList, 1, (int (*) ()) rf_PQ_DegradedWriteQFunc, RF_FALSE);
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/* is the regular Q func the right one to call? */
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}
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/*
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Lost Data and Q - do degraded mode P write
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateWriteDAG)
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{
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if (asmap->numStripeUnitsAccessed != 1 &&
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asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit)
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RF_PANIC();
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rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
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allocList, 1, rf_RecoveryXorFunc, RF_FALSE);
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}
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#endif /* (RF_INCLUDE_DECL_PQ > 0) ||
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* (RF_INCLUDE_RAID6 > 0) */
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