sys/dev/raidframe/rf_pqdeg.c

   1 /*      $NetBSD: rf_pqdeg.c,v 1.7.16.1 2005/03/04 16:50:07 skrll Exp $  */
   2 /*
   3  * Copyright (c) 1995 Carnegie-Mellon University.
   4  * All rights reserved.
   5  *
   6  * Author: Daniel Stodolsky
   7  *
   8  * Permission to use, copy, modify and distribute this software and
   9  * its documentation is hereby granted, provided that both the copyright
  10  * notice and this permission notice appear in all copies of the
  11  * software, derivative works or modified versions, and any portions
  12  * thereof, and that both notices appear in supporting documentation.
  13  *
  14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
  16  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  17  *
  18  * Carnegie Mellon requests users of this software to return to
  19  *
  20  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  21  *  School of Computer Science
  22  *  Carnegie Mellon University
  23  *  Pittsburgh PA 15213-3890
  24  *
  25  * any improvements or extensions that they make and grant Carnegie the
  26  * rights to redistribute these changes.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __KERNEL_RCSID(0, "$NetBSD: rf_pqdeg.c,v 1.7.16.1 2005/03/04 16:50:07 skrll Exp $");
  31
  32 #include "rf_archs.h"
  33
  34 #if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)
  35
  36 #include <dev/raidframe/raidframevar.h>
  37
  38 #include "rf_raid.h"
  39 #include "rf_dag.h"
  40 #include "rf_dagutils.h"
  41 #include "rf_dagfuncs.h"
  42 #include "rf_dagffrd.h"
  43 #include "rf_dagffwr.h"
  44 #include "rf_dagdegrd.h"
  45 #include "rf_dagdegwr.h"
  46 #include "rf_etimer.h"
  47 #include "rf_pqdeg.h"
  48 #include "rf_general.h"
  49 #include "rf_pqdegdags.h"
  50 #include "rf_pq.h"
  51
  52 /*
  53    Degraded mode dag functions for P+Q calculations.
  54
  55    The following nomenclature is used.
  56
  57    PQ_<D><P><Q>_Create{Large,Small}<Write|Read>DAG
  58
  59    where <D><P><Q> are single digits representing the number of failed
  60    data units <D> (0,1,2), parity units <P> (0,1), and Q units <Q>, effecting
  61    the I/O. The reads have only  PQ_<D><P><Q>_CreateReadDAG variants, while
  62    the single fault writes have both large and small write versions. (Single fault
  63    PQ is equivalent to normal mode raid 5 in many aspects.
  64
  65    Some versions degenerate into the same case, and are grouped together below.
  66 */
  67
  68 /* Reads, single failure
  69
  70    we have parity, so we can do a raid 5
  71    reconstruct read.
  72 */
  73
  74 RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateReadDAG)
  75 {
  76         rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
  77 }
  78 /* Reads double failure  */
  79
  80 /*
  81    Q is lost, but not parity
  82    so we can a raid 5 reconstruct read.
  83 */
  84
  85 RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateReadDAG)
  86 {
  87         rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
  88 }
  89 /*
  90   parity is lost, so we need to
  91   do a reconstruct read and recompute
  92   the data with Q.
  93 */
  94
  95 RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateReadDAG)
  96 {
  97         RF_PhysDiskAddr_t *temp;
  98         /* swap P and Q pointers to fake out the DegradedReadDAG code */
  99         temp = asmap->parityInfo;
 100         asmap->parityInfo = asmap->qInfo;
 101         asmap->qInfo = temp;
 102         rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_qRecoveryFuncs);
 103 }
 104 /*
 105   Two data units are dead in this stripe, so we will need read
 106   both P and Q to reconstruct the data. Note that only
 107   one data unit we are reading may actually be missing.
 108 */
 109 RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG);
 110 RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG)
 111 {
 112         rf_PQ_DoubleDegRead(raidPtr, asmap, dag_h, bp, flags, allocList);
 113 }
 114 RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG);
 115 RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG)
 116 {
 117         rf_CreateDoubleDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList);
 118 }
 119 /* Writes, single failure */
 120
 121 RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG);
 122 RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG)
 123 {
 124         if (asmap->numStripeUnitsAccessed != 1 &&
 125             asmap->failedPDAs[0]->numSector !=
 126             raidPtr->Layout.sectorsPerStripeUnit)
 127                 RF_PANIC();
 128         rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp,
 129                       flags, allocList, 2,
 130                       (int (*) (RF_DagNode_t *)) rf_Degraded_100_PQFunc,
 131                       RF_FALSE);
 132 }
 133 /* Dead  P - act like a RAID 5 small write with parity = Q */
 134 RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateSmallWriteDAG)
 135 {
 136         RF_PhysDiskAddr_t *temp;
 137         /* swap P and Q pointers to fake out the DegradedReadDAG code */
 138         temp = asmap->parityInfo;
 139         asmap->parityInfo = asmap->qInfo;
 140         asmap->qInfo = temp;
 141         rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags,
 142                                      allocList, &rf_qFuncs, NULL);
 143 }
 144 /* Dead Q - act like a RAID 5 small write */
 145 RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateSmallWriteDAG)
 146 {
 147         rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags,
 148                                      allocList, &rf_pFuncs, NULL);
 149 }
 150 /* Dead P - act like a RAID 5 large write but for Q */
 151 RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateLargeWriteDAG)
 152 {
 153         RF_PhysDiskAddr_t *temp;
 154         /* swap P and Q pointers to fake out the code */
 155         temp = asmap->parityInfo;
 156         asmap->parityInfo = asmap->qInfo;
 157         asmap->qInfo = temp;
 158         rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags,
 159                                      allocList, 1, rf_RegularQFunc, RF_FALSE);
 160 }
 161 /* Dead Q - act like a RAID 5 large write */
 162 RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateLargeWriteDAG)
 163 {
 164         rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags,
 165                                      allocList, 1, rf_RegularPFunc, RF_FALSE);
 166 }
 167
 168
 169 /*
 170  * writes, double failure
 171  */
 172
 173 /*
 174  * Lost P & Q - do a nonredundant write
 175  */
 176 RF_CREATE_DAG_FUNC_DECL(rf_PQ_011_CreateWriteDAG)
 177 {
 178         rf_CreateNonRedundantWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
 179             RF_IO_TYPE_WRITE);
 180 }
 181 /*
 182    In the two cases below,
 183    A nasty case arises when the write a (strict) portion of a failed stripe unit
 184    and parts of another su. For now, we do not support this.
 185 */
 186
 187 /*
 188   Lost Data and  P - do a Q write.
 189 */
 190 RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateWriteDAG)
 191 {
 192         RF_PhysDiskAddr_t *temp;
 193
 194         if (asmap->numStripeUnitsAccessed != 1 &&
 195             asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit) {
 196                 RF_PANIC();
 197         }
 198         /* swap P and Q to fake out parity code */
 199         temp = asmap->parityInfo;
 200         asmap->parityInfo = asmap->qInfo;
 201         asmap->qInfo = temp;
 202         rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
 203                       allocList, 1,
 204                       (int (*) (RF_DagNode_t *)) rf_PQ_DegradedWriteQFunc,
 205                       RF_FALSE);
 206         /* is the regular Q func the right one to call? */
 207 }
 208 /*
 209    Lost Data and Q - do degraded mode P write
 210 */
 211 RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateWriteDAG)
 212 {
 213         if (asmap->numStripeUnitsAccessed != 1 &&
 214             asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit)
 215                 RF_PANIC();
 216         rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
 217             allocList, 1, rf_RecoveryXorFunc, RF_FALSE);
 218 }
 219 #endif                          /* (RF_INCLUDE_DECL_PQ > 0) ||
 220                                  * (RF_INCLUDE_RAID6 > 0) */