Annotation of sys/dev/raidframe/rf_dagffrd.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: rf_dagffrd.c,v 1.4 2002/12/16 07:01:03 tdeval Exp $ */
2: /* $NetBSD: rf_dagffrd.c,v 1.4 2000/01/07 03:40:58 oster Exp $ */
3:
4: /*
5: * Copyright (c) 1995 Carnegie-Mellon University.
6: * All rights reserved.
7: *
8: * Author: Mark Holland, Daniel Stodolsky, William V. Courtright II
9: *
10: * Permission to use, copy, modify and distribute this software and
11: * its documentation is hereby granted, provided that both the copyright
12: * notice and this permission notice appear in all copies of the
13: * software, derivative works or modified versions, and any portions
14: * thereof, and that both notices appear in supporting documentation.
15: *
16: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
17: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
18: * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
19: *
20: * Carnegie Mellon requests users of this software to return to
21: *
22: * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
23: * School of Computer Science
24: * Carnegie Mellon University
25: * Pittsburgh PA 15213-3890
26: *
27: * any improvements or extensions that they make and grant Carnegie the
28: * rights to redistribute these changes.
29: */
30:
31: /*
32: * rf_dagffrd.c
33: *
34: * Code for creating fault-free read DAGs.
35: *
36: */
37:
38: #include "rf_types.h"
39: #include "rf_raid.h"
40: #include "rf_dag.h"
41: #include "rf_dagutils.h"
42: #include "rf_dagfuncs.h"
43: #include "rf_debugMem.h"
44: #include "rf_memchunk.h"
45: #include "rf_general.h"
46: #include "rf_dagffrd.h"
47:
48: void rf_CreateMirrorReadDAG( RF_Raid_t *, RF_AccessStripeMap_t *,
49: RF_DagHeader_t *, void *, RF_RaidAccessFlags_t, RF_AllocListElem_t *,
50: int (*) (RF_DagNode_t *));
51:
52: /*****************************************************************************
53: *
54: * General comments on DAG creation:
55: *
56: * All DAGs in this file use roll-away error recovery. Each DAG has a single
57: * commit node, usually called "Cmt." If an error occurs before the Cmt node
58: * is reached, the execution engine will halt forward execution and work
59: * backward through the graph, executing the undo functions. Assuming that
60: * each node in the graph prior to the Cmt node are undoable and atomic - or -
61: * does not make changes to permanent state, the graph will fail atomically.
62: * If an error occurs after the Cmt node executes, the engine will roll-forward
63: * through the graph, blindly executing nodes until it reaches the end.
64: * If a graph reaches the end, it is assumed to have completed successfully.
65: *
66: * A graph has only 1 Cmt node.
67: *
68: *****************************************************************************/
69:
70:
71: /*****************************************************************************
72: *
73: * The following wrappers map the standard DAG creation interface to the
74: * DAG creation routines. Additionally, these wrappers enable experimentation
75: * with new DAG structures by providing an extra level of indirection, allowing
76: * the DAG creation routines to be replaced at this single point.
77: *
78: *****************************************************************************/
79:
80: void
81: rf_CreateFaultFreeReadDAG(
82: RF_Raid_t *raidPtr,
83: RF_AccessStripeMap_t *asmap,
84: RF_DagHeader_t *dag_h,
85: void *bp,
86: RF_RaidAccessFlags_t flags,
87: RF_AllocListElem_t *allocList
88: )
89: {
90: rf_CreateNonredundantDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
91: RF_IO_TYPE_READ);
92: }
93:
94:
95: /*****************************************************************************
96: *
97: * DAG creation code begins here.
98: *
99: *****************************************************************************/
100:
101: /*****************************************************************************
102: *
103: * Creates a DAG to perform a nonredundant read or write of data within one
104: * stripe.
105: * For reads, this DAG is as follows:
106: *
107: * /---- read ----\
108: * Header -- Block ---- read ---- Commit -- Terminate
109: * \---- read ----/
110: *
111: * For writes, this DAG is as follows:
112: *
113: * /---- write ----\
114: * Header -- Commit ---- write ---- Block -- Terminate
115: * \---- write ----/
116: *
117: * There is one disk node per stripe unit accessed, and all disk nodes are in
118: * parallel.
119: *
120: * Tricky point here: The first disk node (read or write) is created
121: * normally. Subsequent disk nodes are created by copying the first one,
122: * and modifying a few params. The "succedents" and "antecedents" fields are
123: * _not_ re-created in each node, but rather left pointing to the same array
124: * that was malloc'd when the first node was created. Thus, it's essential
125: * that when this DAG is freed, the succedents and antecedents fields be freed
126: * in ONLY ONE of the read nodes. This does not apply to the "params" field
127: * because it is recreated for each READ node.
128: *
129: * Note that normal-priority accesses do not need to be tagged with their
130: * parity stripe ID, because they will never be promoted. Hence, I've
131: * commented-out the code to do this, and marked it with UNNEEDED.
132: *
133: *****************************************************************************/
134:
135: void
136: rf_CreateNonredundantDAG(
137: RF_Raid_t *raidPtr,
138: RF_AccessStripeMap_t *asmap,
139: RF_DagHeader_t *dag_h,
140: void *bp,
141: RF_RaidAccessFlags_t flags,
142: RF_AllocListElem_t *allocList,
143: RF_IoType_t type
144: )
145: {
146: RF_DagNode_t *nodes, *diskNodes, *blockNode, *commitNode, *termNode;
147: RF_PhysDiskAddr_t *pda = asmap->physInfo;
148: int (*doFunc) (RF_DagNode_t *), (*undoFunc) (RF_DagNode_t *);
149: int i, n, totalNumNodes;
150: char *name;
151:
152: n = asmap->numStripeUnitsAccessed;
153: dag_h->creator = "NonredundantDAG";
154:
155: RF_ASSERT(RF_IO_IS_R_OR_W(type));
156: switch (type) {
157: case RF_IO_TYPE_READ:
158: doFunc = rf_DiskReadFunc;
159: undoFunc = rf_DiskReadUndoFunc;
160: name = "R ";
161: if (rf_dagDebug)
162: printf("[Creating non-redundant read DAG]\n");
163: break;
164: case RF_IO_TYPE_WRITE:
165: doFunc = rf_DiskWriteFunc;
166: undoFunc = rf_DiskWriteUndoFunc;
167: name = "W ";
168: if (rf_dagDebug)
169: printf("[Creating non-redundant write DAG]\n");
170: break;
171: default:
172: RF_PANIC();
173: }
174:
175: /*
176: * For reads, the dag can not commit until the block node is reached.
177: * For writes, the dag commits immediately.
178: */
179: dag_h->numCommitNodes = 1;
180: dag_h->numCommits = 0;
181: dag_h->numSuccedents = 1;
182:
183: /*
184: * Node count:
185: * 1 block node
186: * n data reads (or writes)
187: * 1 commit node
188: * 1 terminator node
189: */
190: RF_ASSERT(n > 0);
191: totalNumNodes = n + 3;
192: RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t),
193: (RF_DagNode_t *), allocList);
194: i = 0;
195: diskNodes = &nodes[i];
196: i += n;
197: blockNode = &nodes[i];
198: i += 1;
199: commitNode = &nodes[i];
200: i += 1;
201: termNode = &nodes[i];
202: i += 1;
203: RF_ASSERT(i == totalNumNodes);
204:
205: /* Initialize nodes. */
206: switch (type) {
207: case RF_IO_TYPE_READ:
208: rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc,
209: rf_NullNodeUndoFunc, NULL, n, 0, 0, 0, dag_h, "Nil",
210: allocList);
211: rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc,
212: rf_NullNodeUndoFunc, NULL, 1, n, 0, 0, dag_h, "Cmt",
213: allocList);
214: rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc,
215: rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm",
216: allocList);
217: break;
218: case RF_IO_TYPE_WRITE:
219: rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc,
220: rf_NullNodeUndoFunc, NULL, 1, 0, 0, 0, dag_h, "Nil",
221: allocList);
222: rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc,
223: rf_NullNodeUndoFunc, NULL, n, 1, 0, 0, dag_h, "Cmt",
224: allocList);
225: rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc,
226: rf_TerminateUndoFunc, NULL, 0, n, 0, 0, dag_h, "Trm",
227: allocList);
228: break;
229: default:
230: RF_PANIC();
231: }
232:
233: for (i = 0; i < n; i++) {
234: RF_ASSERT(pda != NULL);
235: rf_InitNode(&diskNodes[i], rf_wait, RF_FALSE, doFunc, undoFunc,
236: rf_GenericWakeupFunc, 1, 1, 4, 0, dag_h, name, allocList);
237: diskNodes[i].params[0].p = pda;
238: diskNodes[i].params[1].p = pda->bufPtr;
239: /* Parity stripe id is not necessary. */
240: diskNodes[i].params[2].v = 0;
241: diskNodes[i].params[3].v =
242: RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);
243: pda = pda->next;
244: }
245:
246: /*
247: * Connect nodes.
248: */
249:
250: /* Connect hdr to block node. */
251: RF_ASSERT(blockNode->numAntecedents == 0);
252: dag_h->succedents[0] = blockNode;
253:
254: if (type == RF_IO_TYPE_READ) {
255: /* Connecting a nonredundant read DAG. */
256: RF_ASSERT(blockNode->numSuccedents == n);
257: RF_ASSERT(commitNode->numAntecedents == n);
258: for (i = 0; i < n; i++) {
259: /* Connect block node to each read node. */
260: RF_ASSERT(diskNodes[i].numAntecedents == 1);
261: blockNode->succedents[i] = &diskNodes[i];
262: diskNodes[i].antecedents[0] = blockNode;
263: diskNodes[i].antType[0] = rf_control;
264:
265: /* Connect each read node to the commit node. */
266: RF_ASSERT(diskNodes[i].numSuccedents == 1);
267: diskNodes[i].succedents[0] = commitNode;
268: commitNode->antecedents[i] = &diskNodes[i];
269: commitNode->antType[i] = rf_control;
270: }
271: /* Connect the commit node to the term node. */
272: RF_ASSERT(commitNode->numSuccedents == 1);
273: RF_ASSERT(termNode->numAntecedents == 1);
274: RF_ASSERT(termNode->numSuccedents == 0);
275: commitNode->succedents[0] = termNode;
276: termNode->antecedents[0] = commitNode;
277: termNode->antType[0] = rf_control;
278: } else {
279: /* Connecting a nonredundant write DAG. */
280: /* Connect the block node to the commit node. */
281: RF_ASSERT(blockNode->numSuccedents == 1);
282: RF_ASSERT(commitNode->numAntecedents == 1);
283: blockNode->succedents[0] = commitNode;
284: commitNode->antecedents[0] = blockNode;
285: commitNode->antType[0] = rf_control;
286:
287: RF_ASSERT(commitNode->numSuccedents == n);
288: RF_ASSERT(termNode->numAntecedents == n);
289: RF_ASSERT(termNode->numSuccedents == 0);
290: for (i = 0; i < n; i++) {
291: /* Connect the commit node to each write node. */
292: RF_ASSERT(diskNodes[i].numAntecedents == 1);
293: commitNode->succedents[i] = &diskNodes[i];
294: diskNodes[i].antecedents[0] = commitNode;
295: diskNodes[i].antType[0] = rf_control;
296:
297: /* Connect each write node to the term node. */
298: RF_ASSERT(diskNodes[i].numSuccedents == 1);
299: diskNodes[i].succedents[0] = termNode;
300: termNode->antecedents[i] = &diskNodes[i];
301: termNode->antType[i] = rf_control;
302: }
303: }
304: }
305: /*****************************************************************************
306: * Create a fault-free read DAG for RAID level 1.
307: *
308: * Hdr -> Nil -> Rmir -> Cmt -> Trm
309: *
310: * The "Rmir" node schedules a read from the disk in the mirror pair with the
311: * shortest disk queue. The proper queue is selected at Rmir execution. This
312: * deferred mapping is unlike other archs in RAIDframe which generally fix
313: * mapping at DAG creation time.
314: *
315: * Parameters: raidPtr - description of the physical array
316: * asmap - logical & physical addresses for this access
317: * bp - buffer ptr (for holding read data)
318: * flags - general flags (e.g. disk locking)
319: * allocList - list of memory allocated in DAG creation
320: *****************************************************************************/
321:
322: void
323: rf_CreateMirrorReadDAG(
324: RF_Raid_t *raidPtr,
325: RF_AccessStripeMap_t *asmap,
326: RF_DagHeader_t *dag_h,
327: void *bp,
328: RF_RaidAccessFlags_t flags,
329: RF_AllocListElem_t *allocList,
330: int (*readfunc) (RF_DagNode_t *)
331: )
332: {
333: RF_DagNode_t *readNodes, *nodes, *blockNode, *commitNode, *termNode;
334: RF_PhysDiskAddr_t *data_pda = asmap->physInfo;
335: RF_PhysDiskAddr_t *parity_pda = asmap->parityInfo;
336: int i, n, totalNumNodes;
337:
338: n = asmap->numStripeUnitsAccessed;
339: dag_h->creator = "RaidOneReadDAG";
340: if (rf_dagDebug) {
341: printf("[Creating RAID level 1 read DAG]\n");
342: }
343: /*
344: * This dag can not commit until the commit node is reached.
345: * Errors prior to the commit point imply the dag has failed.
346: */
347: dag_h->numCommitNodes = 1;
348: dag_h->numCommits = 0;
349: dag_h->numSuccedents = 1;
350:
351: /*
352: * Node count:
353: * n data reads
354: * 1 block node
355: * 1 commit node
356: * 1 terminator node
357: */
358: RF_ASSERT(n > 0);
359: totalNumNodes = n + 3;
360: RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t),
361: (RF_DagNode_t *), allocList);
362: i = 0;
363: readNodes = &nodes[i];
364: i += n;
365: blockNode = &nodes[i];
366: i += 1;
367: commitNode = &nodes[i];
368: i += 1;
369: termNode = &nodes[i];
370: i += 1;
371: RF_ASSERT(i == totalNumNodes);
372:
373: /* Initialize nodes. */
374: rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc,
375: rf_NullNodeUndoFunc, NULL, n, 0, 0, 0, dag_h, "Nil", allocList);
376: rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc,
377: rf_NullNodeUndoFunc, NULL, 1, n, 0, 0, dag_h, "Cmt", allocList);
378: rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc,
379: rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
380:
381: for (i = 0; i < n; i++) {
382: RF_ASSERT(data_pda != NULL);
383: RF_ASSERT(parity_pda != NULL);
384: rf_InitNode(&readNodes[i], rf_wait, RF_FALSE, readfunc,
385: rf_DiskReadMirrorUndoFunc, rf_GenericWakeupFunc, 1, 1, 5,
386: 0, dag_h, "Rmir", allocList);
387: readNodes[i].params[0].p = data_pda;
388: readNodes[i].params[1].p = data_pda->bufPtr;
389: /* Parity stripe id is not necessary. */
390: readNodes[i].params[2].p = 0;
391: readNodes[i].params[3].v =
392: RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);
393: readNodes[i].params[4].p = parity_pda;
394: data_pda = data_pda->next;
395: parity_pda = parity_pda->next;
396: }
397:
398: /*
399: * Connect nodes.
400: */
401:
402: /* Connect hdr to block node. */
403: RF_ASSERT(blockNode->numAntecedents == 0);
404: dag_h->succedents[0] = blockNode;
405:
406: /* Connect block node to read nodes. */
407: RF_ASSERT(blockNode->numSuccedents == n);
408: for (i = 0; i < n; i++) {
409: RF_ASSERT(readNodes[i].numAntecedents == 1);
410: blockNode->succedents[i] = &readNodes[i];
411: readNodes[i].antecedents[0] = blockNode;
412: readNodes[i].antType[0] = rf_control;
413: }
414:
415: /* Connect read nodes to commit node. */
416: RF_ASSERT(commitNode->numAntecedents == n);
417: for (i = 0; i < n; i++) {
418: RF_ASSERT(readNodes[i].numSuccedents == 1);
419: readNodes[i].succedents[0] = commitNode;
420: commitNode->antecedents[i] = &readNodes[i];
421: commitNode->antType[i] = rf_control;
422: }
423:
424: /* Connect commit node to term node. */
425: RF_ASSERT(commitNode->numSuccedents == 1);
426: RF_ASSERT(termNode->numAntecedents == 1);
427: RF_ASSERT(termNode->numSuccedents == 0);
428: commitNode->succedents[0] = termNode;
429: termNode->antecedents[0] = commitNode;
430: termNode->antType[0] = rf_control;
431: }
432:
433: void
434: rf_CreateMirrorIdleReadDAG(
435: RF_Raid_t *raidPtr,
436: RF_AccessStripeMap_t *asmap,
437: RF_DagHeader_t *dag_h,
438: void *bp,
439: RF_RaidAccessFlags_t flags,
440: RF_AllocListElem_t *allocList
441: )
442: {
443: rf_CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
444: rf_DiskReadMirrorIdleFunc);
445: }
446:
447: void
448: rf_CreateMirrorPartitionReadDAG(
449: RF_Raid_t *raidPtr,
450: RF_AccessStripeMap_t *asmap,
451: RF_DagHeader_t *dag_h,
452: void *bp,
453: RF_RaidAccessFlags_t flags,
454: RF_AllocListElem_t *allocList
455: )
456: {
457: rf_CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
458: rf_DiskReadMirrorPartitionFunc);
459: }
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