| 1 | /* $NetBSD: rf_pqdeg.c,v 1.9 2005/12/11 12:23:37 christos 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 1.9 2005/12/11 12:23:37 christos 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) */ |
| 221 | |