1 /* $NetBSD: rf_raid5.c,v 1.11 2004/01/02 21:41:08 oster Exp $ */ 2 /* 3 * Copyright (c) 1995 Carnegie-Mellon University. 4 * All rights reserved. 5 * 6 * Author: Mark Holland 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 /****************************************************************************** 30 * 31 * rf_raid5.c -- implements RAID Level 5 32 * 33 *****************************************************************************/ 34 35 #include <sys/cdefs.h> 36 __KERNEL_RCSID(0, "$NetBSD: rf_raid5.c,v 1.11 2004/01/02 21:41:08 oster Exp $"); 37 38 #include <dev/raidframe/raidframevar.h> 39 40 #include "rf_raid.h" 41 #include "rf_raid5.h" 42 #include "rf_dag.h" 43 #include "rf_dagffrd.h" 44 #include "rf_dagffwr.h" 45 #include "rf_dagdegrd.h" 46 #include "rf_dagdegwr.h" 47 #include "rf_dagutils.h" 48 #include "rf_general.h" 49 #include "rf_map.h" 50 #include "rf_utils.h" 51 52 typedef struct RF_Raid5ConfigInfo_s { 53 RF_RowCol_t **stripeIdentifier; /* filled in at config time and used 54 * by IdentifyStripe */ 55 } RF_Raid5ConfigInfo_t; 56 57 int 58 rf_ConfigureRAID5(RF_ShutdownList_t **listp, RF_Raid_t *raidPtr, 59 RF_Config_t *cfgPtr) 60 { 61 RF_RaidLayout_t *layoutPtr = &raidPtr->Layout; 62 RF_Raid5ConfigInfo_t *info; 63 RF_RowCol_t i, j, startdisk; 64 65 /* create a RAID level 5 configuration structure */ 66 RF_MallocAndAdd(info, sizeof(RF_Raid5ConfigInfo_t), (RF_Raid5ConfigInfo_t *), raidPtr->cleanupList); 67 if (info == NULL) 68 return (ENOMEM); 69 layoutPtr->layoutSpecificInfo = (void *) info; 70 71 /* the stripe identifier must identify the disks in each stripe, IN 72 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */ 73 info->stripeIdentifier = rf_make_2d_array(raidPtr->numCol, raidPtr->numCol, raidPtr->cleanupList); 74 if (info->stripeIdentifier == NULL) 75 return (ENOMEM); 76 startdisk = 0; 77 for (i = 0; i < raidPtr->numCol; i++) { 78 for (j = 0; j < raidPtr->numCol; j++) { 79 info->stripeIdentifier[i][j] = (startdisk + j) % raidPtr->numCol; 80 } 81 if ((--startdisk) < 0) 82 startdisk = raidPtr->numCol - 1; 83 } 84 85 /* fill in the remaining layout parameters */ 86 layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk; 87 layoutPtr->numDataCol = raidPtr->numCol - 1; 88 layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit; 89 layoutPtr->numParityCol = 1; 90 layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk; 91 92 raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit; 93 94 return (0); 95 } 96 97 int 98 rf_GetDefaultNumFloatingReconBuffersRAID5(RF_Raid_t *raidPtr) 99 { 100 return (20); 101 } 102 103 RF_HeadSepLimit_t 104 rf_GetDefaultHeadSepLimitRAID5(RF_Raid_t *raidPtr) 105 { 106 return (10); 107 } 108 #if !defined(__NetBSD__) && !defined(_KERNEL) 109 /* not currently used */ 110 int 111 rf_ShutdownRAID5(RF_Raid_t *raidPtr) 112 { 113 return (0); 114 } 115 #endif 116 117 void 118 rf_MapSectorRAID5(RF_Raid_t *raidPtr, RF_RaidAddr_t raidSector, 119 RF_RowCol_t *col, RF_SectorNum_t *diskSector, int remap) 120 { 121 RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit; 122 *col = (SUID % raidPtr->numCol); 123 *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit + 124 (raidSector % raidPtr->Layout.sectorsPerStripeUnit); 125 } 126 127 void 128 rf_MapParityRAID5(RF_Raid_t *raidPtr, RF_RaidAddr_t raidSector, 129 RF_RowCol_t *col, RF_SectorNum_t *diskSector, int remap) 130 { 131 RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit; 132 133 *col = raidPtr->Layout.numDataCol - (SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol; 134 *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit + 135 (raidSector % raidPtr->Layout.sectorsPerStripeUnit); 136 } 137 138 void 139 rf_IdentifyStripeRAID5(RF_Raid_t *raidPtr, RF_RaidAddr_t addr, 140 RF_RowCol_t **diskids) 141 { 142 RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr); 143 RF_Raid5ConfigInfo_t *info = (RF_Raid5ConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo; 144 145 *diskids = info->stripeIdentifier[stripeID % raidPtr->numCol]; 146 } 147 148 void 149 rf_MapSIDToPSIDRAID5(RF_RaidLayout_t *layoutPtr, RF_StripeNum_t stripeID, 150 RF_StripeNum_t *psID, RF_ReconUnitNum_t *which_ru) 151 { 152 *which_ru = 0; 153 *psID = stripeID; 154 } 155 /* select an algorithm for performing an access. Returns two pointers, 156 * one to a function that will return information about the DAG, and 157 * another to a function that will create the dag. 158 */ 159 void 160 rf_RaidFiveDagSelect(RF_Raid_t *raidPtr, RF_IoType_t type, 161 RF_AccessStripeMap_t *asmap, 162 RF_VoidFuncPtr *createFunc) 163 { 164 RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout); 165 RF_PhysDiskAddr_t *failedPDA = NULL; 166 RF_RowCol_t fcol; 167 RF_RowStatus_t rstat; 168 int prior_recon; 169 170 RF_ASSERT(RF_IO_IS_R_OR_W(type)); 171 172 if ((asmap->numDataFailed + asmap->numParityFailed > 1) || 173 (raidPtr->numFailures > 1)){ 174 if (rf_dagDebug) 175 RF_ERRORMSG("Multiple disks failed in a single group! Aborting I/O operation.\n"); 176 *createFunc = NULL; 177 return; 178 } else 179 if (asmap->numDataFailed + asmap->numParityFailed == 1) { 180 181 /* if under recon & already reconstructed, redirect 182 * the access to the spare drive and eliminate the 183 * failure indication */ 184 failedPDA = asmap->failedPDAs[0]; 185 fcol = failedPDA->col; 186 rstat = raidPtr->status; 187 prior_recon = (rstat == rf_rs_reconfigured) || ( 188 (rstat == rf_rs_reconstructing) ? 189 rf_CheckRUReconstructed(raidPtr->reconControl->reconMap, failedPDA->startSector) : 0 190 ); 191 if (prior_recon) { 192 RF_RowCol_t oc = failedPDA->col; 193 RF_SectorNum_t oo = failedPDA->startSector; 194 195 if (layoutPtr->map->flags & RF_DISTRIBUTE_SPARE) { /* redirect to dist 196 * spare space */ 197 198 if (failedPDA == asmap->parityInfo) { 199 200 /* parity has failed */ 201 (layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress, 202 &failedPDA->col, &failedPDA->startSector, RF_REMAP); 203 204 if (asmap->parityInfo->next) { /* redir 2nd component, 205 * if any */ 206 RF_PhysDiskAddr_t *p = asmap->parityInfo->next; 207 RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit; 208 p->col = failedPDA->col; 209 p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) + 210 SUoffs; /* cheating: 211 * startSector is not 212 * really a RAID address */ 213 } 214 } else 215 if (asmap->parityInfo->next && failedPDA == asmap->parityInfo->next) { 216 RF_ASSERT(0); /* should not ever 217 * happen */ 218 } else { 219 220 /* data has failed */ 221 (layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress, 222 &failedPDA->col, &failedPDA->startSector, RF_REMAP); 223 224 } 225 226 } else { /* redirect to dedicated spare 227 * space */ 228 229 failedPDA->col = raidPtr->Disks[fcol].spareCol; 230 231 /* the parity may have two distinct 232 * components, both of which may need 233 * to be redirected */ 234 if (asmap->parityInfo->next) { 235 if (failedPDA == asmap->parityInfo) { 236 failedPDA->next->col = failedPDA->col; 237 } else 238 if (failedPDA == asmap->parityInfo->next) { /* paranoid: should 239 * never occur */ 240 asmap->parityInfo->col = failedPDA->col; 241 } 242 } 243 } 244 245 RF_ASSERT(failedPDA->col != -1); 246 247 if (rf_dagDebug || rf_mapDebug) { 248 printf("raid%d: Redirected type '%c' c %d o %ld -> c %d o %ld\n", 249 raidPtr->raidid, type, oc, 250 (long) oo, failedPDA->col, 251 (long) failedPDA->startSector); 252 } 253 asmap->numDataFailed = asmap->numParityFailed = 0; 254 } 255 } 256 /* all dags begin/end with block/unblock node therefore, hdrSucc & 257 * termAnt counts should always be 1 also, these counts should not be 258 * visible outside dag creation routines - manipulating the counts 259 * here should be removed */ 260 if (type == RF_IO_TYPE_READ) { 261 if (asmap->numDataFailed == 0) 262 *createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG; 263 else 264 *createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG; 265 } else { 266 267 268 /* if mirroring, always use large writes. If the access 269 * requires two distinct parity updates, always do a small 270 * write. If the stripe contains a failure but the access 271 * does not, do a small write. The first conditional 272 * (numStripeUnitsAccessed <= numDataCol/2) uses a 273 * less-than-or-equal rather than just a less-than because 274 * when G is 3 or 4, numDataCol/2 is 1, and I want 275 * single-stripe-unit updates to use just one disk. */ 276 if ((asmap->numDataFailed + asmap->numParityFailed) == 0) { 277 if (rf_suppressLocksAndLargeWrites || 278 (((asmap->numStripeUnitsAccessed <= (layoutPtr->numDataCol / 2)) && (layoutPtr->numDataCol != 1)) || 279 (asmap->parityInfo->next != NULL) || rf_CheckStripeForFailures(raidPtr, asmap))) { 280 *createFunc = (RF_VoidFuncPtr) rf_CreateSmallWriteDAG; 281 } else 282 *createFunc = (RF_VoidFuncPtr) rf_CreateLargeWriteDAG; 283 } else { 284 if (asmap->numParityFailed == 1) 285 *createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG; 286 else 287 if (asmap->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit) 288 *createFunc = NULL; 289 else 290 *createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG; 291 } 292 } 293 } 294