1 /* $NetBSD: rf_dagffrd.c,v 1.18 2006/11/16 01:33:23 christos Exp $ */ 2 /* 3 * Copyright (c) 1995 Carnegie-Mellon University. 4 * All rights reserved. 5 * 6 * Author: Mark Holland, Daniel Stodolsky, William V. Courtright II 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 * rf_dagffrd.c 31 * 32 * code for creating fault-free read DAGs 33 * 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: rf_dagffrd.c,v 1.18 2006/11/16 01:33:23 christos Exp $"); 38 39 #include <dev/raidframe/raidframevar.h> 40 41 #include "rf_raid.h" 42 #include "rf_dag.h" 43 #include "rf_dagutils.h" 44 #include "rf_dagfuncs.h" 45 #include "rf_debugMem.h" 46 #include "rf_general.h" 47 #include "rf_dagffrd.h" 48 49 /****************************************************************************** 50 * 51 * General comments on DAG creation: 52 * 53 * All DAGs in this file use roll-away error recovery. Each DAG has a single 54 * commit node, usually called "Cmt." If an error occurs before the Cmt node 55 * is reached, the execution engine will halt forward execution and work 56 * backward through the graph, executing the undo functions. Assuming that 57 * each node in the graph prior to the Cmt node are undoable and atomic - or - 58 * does not make changes to permanent state, the graph will fail atomically. 59 * If an error occurs after the Cmt node executes, the engine will roll-forward 60 * through the graph, blindly executing nodes until it reaches the end. 61 * If a graph reaches the end, it is assumed to have completed successfully. 62 * 63 * A graph has only 1 Cmt node. 64 * 65 */ 66 67 68 /****************************************************************************** 69 * 70 * The following wrappers map the standard DAG creation interface to the 71 * DAG creation routines. Additionally, these wrappers enable experimentation 72 * with new DAG structures by providing an extra level of indirection, allowing 73 * the DAG creation routines to be replaced at this single point. 74 */ 75 76 void 77 rf_CreateFaultFreeReadDAG(RF_Raid_t *raidPtr, RF_AccessStripeMap_t *asmap, 78 RF_DagHeader_t *dag_h, void *bp, 79 RF_RaidAccessFlags_t flags, 80 RF_AllocListElem_t *allocList) 81 { 82 rf_CreateNonredundantDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 83 RF_IO_TYPE_READ); 84 } 85 86 87 /****************************************************************************** 88 * 89 * DAG creation code begins here 90 */ 91 92 /****************************************************************************** 93 * 94 * creates a DAG to perform a nonredundant read or write of data within one 95 * stripe. 96 * For reads, this DAG is as follows: 97 * 98 * /---- read ----\ 99 * Header -- Block ---- read ---- Commit -- Terminate 100 * \---- read ----/ 101 * 102 * For writes, this DAG is as follows: 103 * 104 * /---- write ----\ 105 * Header -- Commit ---- write ---- Block -- Terminate 106 * \---- write ----/ 107 * 108 * There is one disk node per stripe unit accessed, and all disk nodes are in 109 * parallel. 110 * 111 * Tricky point here: The first disk node (read or write) is created 112 * normally. Subsequent disk nodes are created by copying the first one, 113 * and modifying a few params. The "succedents" and "antecedents" fields are 114 * _not_ re-created in each node, but rather left pointing to the same array 115 * that was malloc'd when the first node was created. Thus, it's essential 116 * that when this DAG is freed, the succedents and antecedents fields be freed 117 * in ONLY ONE of the read nodes. This does not apply to the "params" field 118 * because it is recreated for each READ node. 119 * 120 * Note that normal-priority accesses do not need to be tagged with their 121 * parity stripe ID, because they will never be promoted. Hence, I've 122 * commented-out the code to do this, and marked it with UNNEEDED. 123 * 124 *****************************************************************************/ 125 126 void 127 rf_CreateNonredundantDAG(RF_Raid_t *raidPtr, 128 RF_AccessStripeMap_t *asmap, RF_DagHeader_t *dag_h, void *bp, 129 RF_RaidAccessFlags_t flags, RF_AllocListElem_t *allocList, 130 RF_IoType_t type) 131 { 132 RF_DagNode_t *diskNodes, *blockNode, *commitNode, *termNode; 133 RF_DagNode_t *tmpNode, *tmpdiskNode; 134 RF_PhysDiskAddr_t *pda = asmap->physInfo; 135 int (*doFunc) (RF_DagNode_t *), (*undoFunc) (RF_DagNode_t *); 136 int i, n, totalNumNodes; 137 const char *name; 138 139 n = asmap->numStripeUnitsAccessed; 140 dag_h->creator = "NonredundantDAG"; 141 142 RF_ASSERT(RF_IO_IS_R_OR_W(type)); 143 switch (type) { 144 case RF_IO_TYPE_READ: 145 doFunc = rf_DiskReadFunc; 146 undoFunc = rf_DiskReadUndoFunc; 147 name = "R "; 148 #if RF_DEBUG_DAG 149 if (rf_dagDebug) 150 printf("[Creating non-redundant read DAG]\n"); 151 #endif 152 break; 153 case RF_IO_TYPE_WRITE: 154 doFunc = rf_DiskWriteFunc; 155 undoFunc = rf_DiskWriteUndoFunc; 156 name = "W "; 157 #if RF_DEBUG_DAG 158 if (rf_dagDebug) 159 printf("[Creating non-redundant write DAG]\n"); 160 #endif 161 break; 162 default: 163 RF_PANIC(); 164 } 165 166 /* 167 * For reads, the dag can not commit until the block node is reached. 168 * for writes, the dag commits immediately. 169 */ 170 dag_h->numCommitNodes = 1; 171 dag_h->numCommits = 0; 172 dag_h->numSuccedents = 1; 173 174 /* 175 * Node count: 176 * 1 block node 177 * n data reads (or writes) 178 * 1 commit node 179 * 1 terminator node 180 */ 181 RF_ASSERT(n > 0); 182 totalNumNodes = n + 3; 183 184 for (i = 0; i < n; i++) { 185 tmpNode = rf_AllocDAGNode(); 186 tmpNode->list_next = dag_h->nodes; 187 dag_h->nodes = tmpNode; 188 } 189 diskNodes = dag_h->nodes; 190 191 blockNode = rf_AllocDAGNode(); 192 blockNode->list_next = dag_h->nodes; 193 dag_h->nodes = blockNode; 194 195 commitNode = rf_AllocDAGNode(); 196 commitNode->list_next = dag_h->nodes; 197 dag_h->nodes = commitNode; 198 199 termNode = rf_AllocDAGNode(); 200 termNode->list_next = dag_h->nodes; 201 dag_h->nodes = termNode; 202 203 /* initialize nodes */ 204 switch (type) { 205 case RF_IO_TYPE_READ: 206 rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, 207 NULL, n, 0, 0, 0, dag_h, "Nil", allocList); 208 rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc, rf_NullNodeUndoFunc, 209 NULL, 1, n, 0, 0, dag_h, "Cmt", allocList); 210 rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, 211 NULL, 0, 1, 0, 0, dag_h, "Trm", allocList); 212 break; 213 case RF_IO_TYPE_WRITE: 214 rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, 215 NULL, 1, 0, 0, 0, dag_h, "Nil", allocList); 216 rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc, rf_NullNodeUndoFunc, 217 NULL, n, 1, 0, 0, dag_h, "Cmt", allocList); 218 rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, 219 NULL, 0, n, 0, 0, dag_h, "Trm", allocList); 220 break; 221 default: 222 RF_PANIC(); 223 } 224 225 tmpdiskNode = diskNodes; 226 for (i = 0; i < n; i++) { 227 RF_ASSERT(pda != NULL); 228 rf_InitNode(tmpdiskNode, rf_wait, RF_FALSE, doFunc, undoFunc, rf_GenericWakeupFunc, 229 1, 1, 4, 0, dag_h, name, allocList); 230 tmpdiskNode->params[0].p = pda; 231 tmpdiskNode->params[1].p = pda->bufPtr; 232 /* parity stripe id is not necessary */ 233 tmpdiskNode->params[2].v = 0; 234 tmpdiskNode->params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0); 235 pda = pda->next; 236 tmpdiskNode = tmpdiskNode->list_next; 237 } 238 239 /* 240 * Connect nodes. 241 */ 242 243 /* connect hdr to block node */ 244 RF_ASSERT(blockNode->numAntecedents == 0); 245 dag_h->succedents[0] = blockNode; 246 247 if (type == RF_IO_TYPE_READ) { 248 /* connecting a nonredundant read DAG */ 249 RF_ASSERT(blockNode->numSuccedents == n); 250 RF_ASSERT(commitNode->numAntecedents == n); 251 tmpdiskNode = diskNodes; 252 for (i = 0; i < n; i++) { 253 /* connect block node to each read node */ 254 RF_ASSERT(tmpdiskNode->numAntecedents == 1); 255 blockNode->succedents[i] = tmpdiskNode; 256 tmpdiskNode->antecedents[0] = blockNode; 257 tmpdiskNode->antType[0] = rf_control; 258 259 /* connect each read node to the commit node */ 260 RF_ASSERT(tmpdiskNode->numSuccedents == 1); 261 tmpdiskNode->succedents[0] = commitNode; 262 commitNode->antecedents[i] = tmpdiskNode; 263 commitNode->antType[i] = rf_control; 264 tmpdiskNode = tmpdiskNode->list_next; 265 } 266 /* connect the commit node to the term node */ 267 RF_ASSERT(commitNode->numSuccedents == 1); 268 RF_ASSERT(termNode->numAntecedents == 1); 269 RF_ASSERT(termNode->numSuccedents == 0); 270 commitNode->succedents[0] = termNode; 271 termNode->antecedents[0] = commitNode; 272 termNode->antType[0] = rf_control; 273 } else { 274 /* connecting a nonredundant write DAG */ 275 /* connect the block node to the commit node */ 276 RF_ASSERT(blockNode->numSuccedents == 1); 277 RF_ASSERT(commitNode->numAntecedents == 1); 278 blockNode->succedents[0] = commitNode; 279 commitNode->antecedents[0] = blockNode; 280 commitNode->antType[0] = rf_control; 281 282 RF_ASSERT(commitNode->numSuccedents == n); 283 RF_ASSERT(termNode->numAntecedents == n); 284 RF_ASSERT(termNode->numSuccedents == 0); 285 tmpdiskNode = diskNodes; 286 for (i = 0; i < n; i++) { 287 /* connect the commit node to each write node */ 288 RF_ASSERT(tmpdiskNode->numAntecedents == 1); 289 commitNode->succedents[i] = tmpdiskNode; 290 tmpdiskNode->antecedents[0] = commitNode; 291 tmpdiskNode->antType[0] = rf_control; 292 293 /* connect each write node to the term node */ 294 RF_ASSERT(tmpdiskNode->numSuccedents == 1); 295 tmpdiskNode->succedents[0] = termNode; 296 termNode->antecedents[i] = tmpdiskNode; 297 termNode->antType[i] = rf_control; 298 tmpdiskNode = tmpdiskNode->list_next; 299 } 300 } 301 } 302 /****************************************************************************** 303 * Create a fault-free read DAG for RAID level 1 304 * 305 * Hdr -> Nil -> Rmir -> Cmt -> Trm 306 * 307 * The "Rmir" node schedules a read from the disk in the mirror pair with the 308 * shortest disk queue. the proper queue is selected at Rmir execution. this 309 * deferred mapping is unlike other archs in RAIDframe which generally fix 310 * mapping at DAG creation time. 311 * 312 * Parameters: raidPtr - description of the physical array 313 * asmap - logical & physical addresses for this access 314 * bp - buffer ptr (for holding read data) 315 * flags - general flags (e.g. disk locking) 316 * allocList - list of memory allocated in DAG creation 317 *****************************************************************************/ 318 319 static void 320 CreateMirrorReadDAG(RF_Raid_t *raidPtr, RF_AccessStripeMap_t *asmap, 321 RF_DagHeader_t *dag_h, void *bp, 322 RF_RaidAccessFlags_t flags, RF_AllocListElem_t *allocList, 323 int (*readfunc) (RF_DagNode_t * node)) 324 { 325 RF_DagNode_t *readNodes, *blockNode, *commitNode, *termNode; 326 RF_DagNode_t *tmpNode, *tmpreadNode; 327 RF_PhysDiskAddr_t *data_pda = asmap->physInfo; 328 RF_PhysDiskAddr_t *parity_pda = asmap->parityInfo; 329 int i, n, totalNumNodes; 330 331 n = asmap->numStripeUnitsAccessed; 332 dag_h->creator = "RaidOneReadDAG"; 333 #if RF_DEBUG_DAG 334 if (rf_dagDebug) { 335 printf("[Creating RAID level 1 read DAG]\n"); 336 } 337 #endif 338 /* 339 * This dag can not commit until the commit node is reached 340 * errors prior to the commit point imply the dag has failed. 341 */ 342 dag_h->numCommitNodes = 1; 343 dag_h->numCommits = 0; 344 dag_h->numSuccedents = 1; 345 346 /* 347 * Node count: 348 * n data reads 349 * 1 block node 350 * 1 commit node 351 * 1 terminator node 352 */ 353 RF_ASSERT(n > 0); 354 totalNumNodes = n + 3; 355 356 for (i = 0; i < n; i++) { 357 tmpNode = rf_AllocDAGNode(); 358 tmpNode->list_next = dag_h->nodes; 359 dag_h->nodes = tmpNode; 360 } 361 readNodes = dag_h->nodes; 362 363 blockNode = rf_AllocDAGNode(); 364 blockNode->list_next = dag_h->nodes; 365 dag_h->nodes = blockNode; 366 367 commitNode = rf_AllocDAGNode(); 368 commitNode->list_next = dag_h->nodes; 369 dag_h->nodes = commitNode; 370 371 termNode = rf_AllocDAGNode(); 372 termNode->list_next = dag_h->nodes; 373 dag_h->nodes = termNode; 374 375 /* initialize nodes */ 376 rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, 377 rf_NullNodeUndoFunc, NULL, n, 0, 0, 0, dag_h, "Nil", allocList); 378 rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc, 379 rf_NullNodeUndoFunc, NULL, 1, n, 0, 0, dag_h, "Cmt", allocList); 380 rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, 381 rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList); 382 383 tmpreadNode = readNodes; 384 for (i = 0; i < n; i++) { 385 RF_ASSERT(data_pda != NULL); 386 RF_ASSERT(parity_pda != NULL); 387 rf_InitNode(tmpreadNode, rf_wait, RF_FALSE, readfunc, 388 rf_DiskReadMirrorUndoFunc, rf_GenericWakeupFunc, 1, 1, 5, 0, dag_h, 389 "Rmir", allocList); 390 tmpreadNode->params[0].p = data_pda; 391 tmpreadNode->params[1].p = data_pda->bufPtr; 392 /* parity stripe id is not necessary */ 393 tmpreadNode->params[2].p = 0; 394 tmpreadNode->params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0); 395 tmpreadNode->params[4].p = parity_pda; 396 data_pda = data_pda->next; 397 parity_pda = parity_pda->next; 398 tmpreadNode = tmpreadNode->list_next; 399 } 400 401 /* 402 * Connect nodes 403 */ 404 405 /* connect hdr to block node */ 406 RF_ASSERT(blockNode->numAntecedents == 0); 407 dag_h->succedents[0] = blockNode; 408 409 /* connect block node to read nodes */ 410 RF_ASSERT(blockNode->numSuccedents == n); 411 tmpreadNode = readNodes; 412 for (i = 0; i < n; i++) { 413 RF_ASSERT(tmpreadNode->numAntecedents == 1); 414 blockNode->succedents[i] = tmpreadNode; 415 tmpreadNode->antecedents[0] = blockNode; 416 tmpreadNode->antType[0] = rf_control; 417 tmpreadNode = tmpreadNode->list_next; 418 } 419 420 /* connect read nodes to commit node */ 421 RF_ASSERT(commitNode->numAntecedents == n); 422 tmpreadNode = readNodes; 423 for (i = 0; i < n; i++) { 424 RF_ASSERT(tmpreadNode->numSuccedents == 1); 425 tmpreadNode->succedents[0] = commitNode; 426 commitNode->antecedents[i] = tmpreadNode; 427 commitNode->antType[i] = rf_control; 428 tmpreadNode = tmpreadNode->list_next; 429 } 430 431 /* connect commit node to term node */ 432 RF_ASSERT(commitNode->numSuccedents == 1); 433 RF_ASSERT(termNode->numAntecedents == 1); 434 RF_ASSERT(termNode->numSuccedents == 0); 435 commitNode->succedents[0] = termNode; 436 termNode->antecedents[0] = commitNode; 437 termNode->antType[0] = rf_control; 438 } 439 440 void 441 rf_CreateMirrorIdleReadDAG( 442 RF_Raid_t * raidPtr, 443 RF_AccessStripeMap_t * asmap, 444 RF_DagHeader_t * dag_h, 445 void *bp, 446 RF_RaidAccessFlags_t flags, 447 RF_AllocListElem_t * allocList) 448 { 449 CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 450 rf_DiskReadMirrorIdleFunc); 451 } 452 453 #if (RF_INCLUDE_CHAINDECLUSTER > 0) || (RF_INCLUDE_INTERDECLUSTER > 0) 454 455 void 456 rf_CreateMirrorPartitionReadDAG(RF_Raid_t *raidPtr, 457 RF_AccessStripeMap_t *asmap, 458 RF_DagHeader_t *dag_h, void *bp, 459 RF_RaidAccessFlags_t flags, 460 RF_AllocListElem_t *allocList) 461 { 462 CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 463 rf_DiskReadMirrorPartitionFunc); 464 } 465 #endif 466