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/* $OpenBSD: rf_pqdeg.c,v 1.4 2000/01/11 18:02:22 peter Exp $ */
/* $NetBSD: rf_pqdeg.c,v 1.5 2000/01/07 03:41:04 oster Exp $ */
/*
* Copyright (c) 1995 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Daniel Stodolsky
*
* 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.
*/
#include "rf_archs.h"
#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)
#include "rf_types.h"
#include "rf_raid.h"
#include "rf_dag.h"
#include "rf_dagutils.h"
#include "rf_dagfuncs.h"
#include "rf_dagffrd.h"
#include "rf_dagffwr.h"
#include "rf_dagdegrd.h"
#include "rf_dagdegwr.h"
#include "rf_etimer.h"
#include "rf_pqdeg.h"
#include "rf_general.h"
#include "rf_pqdegdags.h"
#include "rf_pq.h"
/*
Degraded mode dag functions for P+Q calculations.
The following nomenclature is used.
PQ_<D><P><Q>_Create{Large,Small}<Write|Read>DAG
where <D><P><Q> are single digits representing the number of failed
data units <D> (0,1,2), parity units <P> (0,1), and Q units <Q>, effecting
the I/O. The reads have only PQ_<D><P><Q>_CreateReadDAG variants, while
the single fault writes have both large and small write versions. (Single fault
PQ is equivalent to normal mode raid 5 in many aspects.
Some versions degenerate into the same case, and are grouped together below.
*/
/* Reads, single failure
we have parity, so we can do a raid 5
reconstruct read.
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateReadDAG)
{
rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
}
/* Reads double failure */
/*
Q is lost, but not parity
so we can a raid 5 reconstruct read.
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateReadDAG)
{
rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
}
/*
parity is lost, so we need to
do a reconstruct read and recompute
the data with Q.
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateReadDAG)
{
RF_PhysDiskAddr_t *temp;
/* swap P and Q pointers to fake out the DegradedReadDAG code */
temp = asmap->parityInfo;
asmap->parityInfo = asmap->qInfo;
asmap->qInfo = temp;
rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_qRecoveryFuncs);
}
/*
Two data units are dead in this stripe, so we will need read
both P and Q to reconstruct the data. Note that only
one data unit we are reading may actually be missing.
*/
RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG);
RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG)
{
rf_PQ_DoubleDegRead(raidPtr, asmap, dag_h, bp, flags, allocList);
}
RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG);
RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG)
{
rf_CreateDoubleDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList);
}
/* Writes, single failure */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG);
RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG)
{
if (asmap->numStripeUnitsAccessed != 1 &&
asmap->failedPDAs[0]->numSector !=
raidPtr->Layout.sectorsPerStripeUnit)
RF_PANIC();
rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp,
flags, allocList, 2,
(int (*) (RF_DagNode_t *)) rf_Degraded_100_PQFunc,
RF_FALSE);
}
/* Dead P - act like a RAID 5 small write with parity = Q */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateSmallWriteDAG)
{
RF_PhysDiskAddr_t *temp;
/* swap P and Q pointers to fake out the DegradedReadDAG code */
temp = asmap->parityInfo;
asmap->parityInfo = asmap->qInfo;
asmap->qInfo = temp;
rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags,
allocList, &rf_qFuncs, NULL);
}
/* Dead Q - act like a RAID 5 small write */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateSmallWriteDAG)
{
rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags,
allocList, &rf_pFuncs, NULL);
}
/* Dead P - act like a RAID 5 large write but for Q */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateLargeWriteDAG)
{
RF_PhysDiskAddr_t *temp;
/* swap P and Q pointers to fake out the code */
temp = asmap->parityInfo;
asmap->parityInfo = asmap->qInfo;
asmap->qInfo = temp;
rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags,
allocList, 1, rf_RegularQFunc, RF_FALSE);
}
/* Dead Q - act like a RAID 5 large write */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateLargeWriteDAG)
{
rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags,
allocList, 1, rf_RegularPFunc, RF_FALSE);
}
/*
* writes, double failure
*/
/*
* Lost P & Q - do a nonredundant write
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_011_CreateWriteDAG)
{
rf_CreateNonRedundantWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
RF_IO_TYPE_WRITE);
}
/*
In the two cases below,
A nasty case arises when the write a (strict) portion of a failed stripe unit
and parts of another su. For now, we do not support this.
*/
/*
Lost Data and P - do a Q write.
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateWriteDAG)
{
RF_PhysDiskAddr_t *temp;
if (asmap->numStripeUnitsAccessed != 1 &&
asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit) {
RF_PANIC();
}
/* swap P and Q to fake out parity code */
temp = asmap->parityInfo;
asmap->parityInfo = asmap->qInfo;
asmap->qInfo = temp;
rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
allocList, 1,
(int (*) (RF_DagNode_t *)) rf_PQ_DegradedWriteQFunc,
RF_FALSE);
/* is the regular Q func the right one to call? */
}
/*
Lost Data and Q - do degraded mode P write
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateWriteDAG)
{
if (asmap->numStripeUnitsAccessed != 1 &&
asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit)
RF_PANIC();
rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
allocList, 1, rf_RecoveryXorFunc, RF_FALSE);
}
#endif /* (RF_INCLUDE_DECL_PQ > 0) ||
* (RF_INCLUDE_RAID6 > 0) */
|
