1 /* $NetBSD: rf_raid5.c,v 1.7 2002/09/23 02:40:09 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 1.7 2002/09/23 02:40:09 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( 59 RF_ShutdownList_t ** listp, 60 RF_Raid_t * raidPtr, 61 RF_Config_t * cfgPtr) 62 { 63 RF_RaidLayout_t *layoutPtr = &raidPtr->Layout; 64 RF_Raid5ConfigInfo_t *info; 65 RF_RowCol_t i, j, startdisk; 66 67 /* create a RAID level 5 configuration structure */ 68 RF_MallocAndAdd(info, sizeof(RF_Raid5ConfigInfo_t), (RF_Raid5ConfigInfo_t *), raidPtr->cleanupList); 69 if (info == NULL) 70 return (ENOMEM); 71 layoutPtr->layoutSpecificInfo = (void *) info; 72 73 RF_ASSERT(raidPtr->numRow == 1); 74 75 /* the stripe identifier must identify the disks in each stripe, IN 76 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */ 77 info->stripeIdentifier = rf_make_2d_array(raidPtr->numCol, raidPtr->numCol, raidPtr->cleanupList); 78 if (info->stripeIdentifier == NULL) 79 return (ENOMEM); 80 startdisk = 0; 81 for (i = 0; i < raidPtr->numCol; i++) { 82 for (j = 0; j < raidPtr->numCol; j++) { 83 info->stripeIdentifier[i][j] = (startdisk + j) % raidPtr->numCol; 84 } 85 if ((--startdisk) < 0) 86 startdisk = raidPtr->numCol - 1; 87 } 88 89 /* fill in the remaining layout parameters */ 90 layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk; 91 layoutPtr->numDataCol = raidPtr->numCol - 1; 92 layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit; 93 layoutPtr->numParityCol = 1; 94 layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk; 95 96 raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit; 97 98 return (0); 99 } 100 101 int 102 rf_GetDefaultNumFloatingReconBuffersRAID5(RF_Raid_t * raidPtr) 103 { 104 return (20); 105 } 106 107 RF_HeadSepLimit_t 108 rf_GetDefaultHeadSepLimitRAID5(RF_Raid_t * raidPtr) 109 { 110 return (10); 111 } 112 #if !defined(__NetBSD__) && !defined(_KERNEL) 113 /* not currently used */ 114 int 115 rf_ShutdownRAID5(RF_Raid_t * raidPtr) 116 { 117 return (0); 118 } 119 #endif 120 121 void 122 rf_MapSectorRAID5( 123 RF_Raid_t * raidPtr, 124 RF_RaidAddr_t raidSector, 125 RF_RowCol_t * row, 126 RF_RowCol_t * col, 127 RF_SectorNum_t * diskSector, 128 int remap) 129 { 130 RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit; 131 *row = 0; 132 *col = (SUID % raidPtr->numCol); 133 *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit + 134 (raidSector % raidPtr->Layout.sectorsPerStripeUnit); 135 } 136 137 void 138 rf_MapParityRAID5( 139 RF_Raid_t * raidPtr, 140 RF_RaidAddr_t raidSector, 141 RF_RowCol_t * row, 142 RF_RowCol_t * col, 143 RF_SectorNum_t * diskSector, 144 int remap) 145 { 146 RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit; 147 148 *row = 0; 149 *col = raidPtr->Layout.numDataCol - (SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol; 150 *diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit + 151 (raidSector % raidPtr->Layout.sectorsPerStripeUnit); 152 } 153 154 void 155 rf_IdentifyStripeRAID5( 156 RF_Raid_t * raidPtr, 157 RF_RaidAddr_t addr, 158 RF_RowCol_t ** diskids, 159 RF_RowCol_t * outRow) 160 { 161 RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr); 162 RF_Raid5ConfigInfo_t *info = (RF_Raid5ConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo; 163 164 *outRow = 0; 165 *diskids = info->stripeIdentifier[stripeID % raidPtr->numCol]; 166 } 167 168 void 169 rf_MapSIDToPSIDRAID5( 170 RF_RaidLayout_t * layoutPtr, 171 RF_StripeNum_t stripeID, 172 RF_StripeNum_t * psID, 173 RF_ReconUnitNum_t * which_ru) 174 { 175 *which_ru = 0; 176 *psID = stripeID; 177 } 178 /* select an algorithm for performing an access. Returns two pointers, 179 * one to a function that will return information about the DAG, and 180 * another to a function that will create the dag. 181 */ 182 void 183 rf_RaidFiveDagSelect( 184 RF_Raid_t * raidPtr, 185 RF_IoType_t type, 186 RF_AccessStripeMap_t * asmap, 187 RF_VoidFuncPtr * createFunc) 188 { 189 RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout); 190 RF_PhysDiskAddr_t *failedPDA = NULL; 191 RF_RowCol_t frow, fcol; 192 RF_RowStatus_t rstat; 193 int prior_recon; 194 195 RF_ASSERT(RF_IO_IS_R_OR_W(type)); 196 197 if (asmap->numDataFailed + asmap->numParityFailed > 1) { 198 RF_ERRORMSG("Multiple disks failed in a single group! Aborting I/O operation.\n"); 199 /* *infoFunc = */ *createFunc = NULL; 200 return; 201 } else 202 if (asmap->numDataFailed + asmap->numParityFailed == 1) { 203 204 /* if under recon & already reconstructed, redirect 205 * the access to the spare drive and eliminate the 206 * failure indication */ 207 failedPDA = asmap->failedPDAs[0]; 208 frow = failedPDA->row; 209 fcol = failedPDA->col; 210 rstat = raidPtr->status[failedPDA->row]; 211 prior_recon = (rstat == rf_rs_reconfigured) || ( 212 (rstat == rf_rs_reconstructing) ? 213 rf_CheckRUReconstructed(raidPtr->reconControl[frow]->reconMap, failedPDA->startSector) : 0 214 ); 215 if (prior_recon) { 216 RF_RowCol_t or = failedPDA->row, oc = failedPDA->col; 217 RF_SectorNum_t oo = failedPDA->startSector; 218 219 if (layoutPtr->map->flags & RF_DISTRIBUTE_SPARE) { /* redirect to dist 220 * spare space */ 221 222 if (failedPDA == asmap->parityInfo) { 223 224 /* parity has failed */ 225 (layoutPtr->map->MapParity) (raidPtr, failedPDA->raidAddress, &failedPDA->row, 226 &failedPDA->col, &failedPDA->startSector, RF_REMAP); 227 228 if (asmap->parityInfo->next) { /* redir 2nd component, 229 * if any */ 230 RF_PhysDiskAddr_t *p = asmap->parityInfo->next; 231 RF_SectorNum_t SUoffs = p->startSector % layoutPtr->sectorsPerStripeUnit; 232 p->row = failedPDA->row; 233 p->col = failedPDA->col; 234 p->startSector = rf_RaidAddressOfPrevStripeUnitBoundary(layoutPtr, failedPDA->startSector) + 235 SUoffs; /* cheating: 236 * startSector is not 237 * really a RAID address */ 238 } 239 } else 240 if (asmap->parityInfo->next && failedPDA == asmap->parityInfo->next) { 241 RF_ASSERT(0); /* should not ever 242 * happen */ 243 } else { 244 245 /* data has failed */ 246 (layoutPtr->map->MapSector) (raidPtr, failedPDA->raidAddress, &failedPDA->row, 247 &failedPDA->col, &failedPDA->startSector, RF_REMAP); 248 249 } 250 251 } else { /* redirect to dedicated spare 252 * space */ 253 254 failedPDA->row = raidPtr->Disks[frow][fcol].spareRow; 255 failedPDA->col = raidPtr->Disks[frow][fcol].spareCol; 256 257 /* the parity may have two distinct 258 * components, both of which may need 259 * to be redirected */ 260 if (asmap->parityInfo->next) { 261 if (failedPDA == asmap->parityInfo) { 262 failedPDA->next->row = failedPDA->row; 263 failedPDA->next->col = failedPDA->col; 264 } else 265 if (failedPDA == asmap->parityInfo->next) { /* paranoid: should 266 * never occur */ 267 asmap->parityInfo->row = failedPDA->row; 268 asmap->parityInfo->col = failedPDA->col; 269 } 270 } 271 } 272 273 RF_ASSERT(failedPDA->col != -1); 274 275 if (rf_dagDebug || rf_mapDebug) { 276 printf("raid%d: Redirected type '%c' r %d c %d o %ld -> r %d c %d o %ld\n", 277 raidPtr->raidid, type, or, oc, 278 (long) oo, failedPDA->row, 279 failedPDA->col, 280 (long) failedPDA->startSector); 281 } 282 asmap->numDataFailed = asmap->numParityFailed = 0; 283 } 284 } 285 /* all dags begin/end with block/unblock node therefore, hdrSucc & 286 * termAnt counts should always be 1 also, these counts should not be 287 * visible outside dag creation routines - manipulating the counts 288 * here should be removed */ 289 if (type == RF_IO_TYPE_READ) { 290 if (asmap->numDataFailed == 0) 291 *createFunc = (RF_VoidFuncPtr) rf_CreateFaultFreeReadDAG; 292 else 293 *createFunc = (RF_VoidFuncPtr) rf_CreateRaidFiveDegradedReadDAG; 294 } else { 295 296 297 /* if mirroring, always use large writes. If the access 298 * requires two distinct parity updates, always do a small 299 * write. If the stripe contains a failure but the access 300 * does not, do a small write. The first conditional 301 * (numStripeUnitsAccessed <= numDataCol/2) uses a 302 * less-than-or-equal rather than just a less-than because 303 * when G is 3 or 4, numDataCol/2 is 1, and I want 304 * single-stripe-unit updates to use just one disk. */ 305 if ((asmap->numDataFailed + asmap->numParityFailed) == 0) { 306 if (rf_suppressLocksAndLargeWrites || 307 (((asmap->numStripeUnitsAccessed <= (layoutPtr->numDataCol / 2)) && (layoutPtr->numDataCol != 1)) || 308 (asmap->parityInfo->next != NULL) || rf_CheckStripeForFailures(raidPtr, asmap))) { 309 *createFunc = (RF_VoidFuncPtr) rf_CreateSmallWriteDAG; 310 } else 311 *createFunc = (RF_VoidFuncPtr) rf_CreateLargeWriteDAG; 312 } else { 313 if (asmap->numParityFailed == 1) 314 *createFunc = (RF_VoidFuncPtr) rf_CreateNonRedundantWriteDAG; 315 else 316 if (asmap->numStripeUnitsAccessed != 1 && failedPDA->numSector != layoutPtr->sectorsPerStripeUnit) 317 *createFunc = NULL; 318 else 319 *createFunc = (RF_VoidFuncPtr) rf_CreateDegradedWriteDAG; 320 } 321 } 322 } 323