440 lines
14 KiB
C
440 lines
14 KiB
C
/* $FreeBSD$ */
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/* $NetBSD: rf_dagffrd.c,v 1.4 2000/01/07 03:40:58 oster Exp $ */
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/*
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* Copyright (c) 1995 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Author: Mark Holland, Daniel Stodolsky, William V. Courtright II
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/*
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* rf_dagffrd.c
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*
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* code for creating fault-free read DAGs
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*
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*/
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#include <dev/raidframe/rf_types.h>
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#include <dev/raidframe/rf_raid.h>
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#include <dev/raidframe/rf_dag.h>
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#include <dev/raidframe/rf_dagutils.h>
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#include <dev/raidframe/rf_dagfuncs.h>
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#include <dev/raidframe/rf_debugMem.h>
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#include <dev/raidframe/rf_memchunk.h>
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#include <dev/raidframe/rf_general.h>
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#include <dev/raidframe/rf_dagffrd.h>
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/******************************************************************************
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*
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* General comments on DAG creation:
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*
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* All DAGs in this file use roll-away error recovery. Each DAG has a single
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* commit node, usually called "Cmt." If an error occurs before the Cmt node
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* is reached, the execution engine will halt forward execution and work
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* backward through the graph, executing the undo functions. Assuming that
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* each node in the graph prior to the Cmt node are undoable and atomic - or -
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* does not make changes to permanent state, the graph will fail atomically.
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* If an error occurs after the Cmt node executes, the engine will roll-forward
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* through the graph, blindly executing nodes until it reaches the end.
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* If a graph reaches the end, it is assumed to have completed successfully.
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*
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* A graph has only 1 Cmt node.
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*
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*/
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/******************************************************************************
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*
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* The following wrappers map the standard DAG creation interface to the
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* DAG creation routines. Additionally, these wrappers enable experimentation
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* with new DAG structures by providing an extra level of indirection, allowing
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* the DAG creation routines to be replaced at this single point.
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*/
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void
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rf_CreateFaultFreeReadDAG(
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RF_Raid_t * raidPtr,
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RF_AccessStripeMap_t * asmap,
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RF_DagHeader_t * dag_h,
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void *bp,
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RF_RaidAccessFlags_t flags,
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RF_AllocListElem_t * allocList)
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{
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rf_CreateNonredundantDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
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RF_IO_TYPE_READ);
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}
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/******************************************************************************
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*
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* DAG creation code begins here
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*/
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/******************************************************************************
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*
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* creates a DAG to perform a nonredundant read or write of data within one
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* stripe.
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* For reads, this DAG is as follows:
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*
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* /---- read ----\
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* Header -- Block ---- read ---- Commit -- Terminate
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* \---- read ----/
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*
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* For writes, this DAG is as follows:
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*
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* /---- write ----\
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* Header -- Commit ---- write ---- Block -- Terminate
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* \---- write ----/
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*
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* There is one disk node per stripe unit accessed, and all disk nodes are in
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* parallel.
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*
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* Tricky point here: The first disk node (read or write) is created
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* normally. Subsequent disk nodes are created by copying the first one,
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* and modifying a few params. The "succedents" and "antecedents" fields are
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* _not_ re-created in each node, but rather left pointing to the same array
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* that was malloc'd when the first node was created. Thus, it's essential
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* that when this DAG is freed, the succedents and antecedents fields be freed
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* in ONLY ONE of the read nodes. This does not apply to the "params" field
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* because it is recreated for each READ node.
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*
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* Note that normal-priority accesses do not need to be tagged with their
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* parity stripe ID, because they will never be promoted. Hence, I've
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* commented-out the code to do this, and marked it with UNNEEDED.
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*
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*****************************************************************************/
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void
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rf_CreateNonredundantDAG(
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RF_Raid_t * raidPtr,
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RF_AccessStripeMap_t * asmap,
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RF_DagHeader_t * dag_h,
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void *bp,
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RF_RaidAccessFlags_t flags,
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RF_AllocListElem_t * allocList,
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RF_IoType_t type)
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{
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RF_DagNode_t *nodes, *diskNodes, *blockNode, *commitNode, *termNode;
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RF_PhysDiskAddr_t *pda = asmap->physInfo;
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int (*doFunc) (RF_DagNode_t *), (*undoFunc) (RF_DagNode_t *);
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int i, n, totalNumNodes;
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char *name;
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n = asmap->numStripeUnitsAccessed;
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dag_h->creator = "NonredundantDAG";
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RF_ASSERT(RF_IO_IS_R_OR_W(type));
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switch (type) {
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case RF_IO_TYPE_READ:
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doFunc = rf_DiskReadFunc;
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undoFunc = rf_DiskReadUndoFunc;
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name = "R ";
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if (rf_dagDebug)
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printf("[Creating non-redundant read DAG]\n");
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break;
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case RF_IO_TYPE_WRITE:
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doFunc = rf_DiskWriteFunc;
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undoFunc = rf_DiskWriteUndoFunc;
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name = "W ";
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if (rf_dagDebug)
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printf("[Creating non-redundant write DAG]\n");
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break;
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default:
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RF_PANIC();
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}
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/*
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* For reads, the dag can not commit until the block node is reached.
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* for writes, the dag commits immediately.
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*/
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dag_h->numCommitNodes = 1;
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dag_h->numCommits = 0;
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dag_h->numSuccedents = 1;
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/*
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* Node count:
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* 1 block node
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* n data reads (or writes)
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* 1 commit node
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* 1 terminator node
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*/
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RF_ASSERT(n > 0);
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totalNumNodes = n + 3;
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RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t),
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(RF_DagNode_t *), allocList);
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i = 0;
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diskNodes = &nodes[i];
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i += n;
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blockNode = &nodes[i];
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i += 1;
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commitNode = &nodes[i];
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i += 1;
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termNode = &nodes[i];
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i += 1;
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RF_ASSERT(i == totalNumNodes);
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/* initialize nodes */
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switch (type) {
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case RF_IO_TYPE_READ:
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rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
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NULL, n, 0, 0, 0, dag_h, "Nil", allocList);
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rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
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NULL, 1, n, 0, 0, dag_h, "Cmt", allocList);
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rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc,
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NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
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break;
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case RF_IO_TYPE_WRITE:
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rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
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NULL, 1, 0, 0, 0, dag_h, "Nil", allocList);
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rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
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NULL, n, 1, 0, 0, dag_h, "Cmt", allocList);
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rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc,
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NULL, 0, n, 0, 0, dag_h, "Trm", allocList);
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break;
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default:
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RF_PANIC();
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}
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for (i = 0; i < n; i++) {
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RF_ASSERT(pda != NULL);
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rf_InitNode(&diskNodes[i], rf_wait, RF_FALSE, doFunc, undoFunc, rf_GenericWakeupFunc,
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1, 1, 4, 0, dag_h, name, allocList);
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diskNodes[i].params[0].p = pda;
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diskNodes[i].params[1].p = pda->bufPtr;
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/* parity stripe id is not necessary */
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diskNodes[i].params[2].v = 0;
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diskNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);
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pda = pda->next;
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}
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/*
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* Connect nodes.
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*/
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/* connect hdr to block node */
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RF_ASSERT(blockNode->numAntecedents == 0);
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dag_h->succedents[0] = blockNode;
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if (type == RF_IO_TYPE_READ) {
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/* connecting a nonredundant read DAG */
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RF_ASSERT(blockNode->numSuccedents == n);
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RF_ASSERT(commitNode->numAntecedents == n);
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for (i = 0; i < n; i++) {
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/* connect block node to each read node */
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RF_ASSERT(diskNodes[i].numAntecedents == 1);
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blockNode->succedents[i] = &diskNodes[i];
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diskNodes[i].antecedents[0] = blockNode;
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diskNodes[i].antType[0] = rf_control;
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/* connect each read node to the commit node */
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RF_ASSERT(diskNodes[i].numSuccedents == 1);
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diskNodes[i].succedents[0] = commitNode;
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commitNode->antecedents[i] = &diskNodes[i];
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commitNode->antType[i] = rf_control;
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}
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/* connect the commit node to the term node */
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RF_ASSERT(commitNode->numSuccedents == 1);
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RF_ASSERT(termNode->numAntecedents == 1);
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RF_ASSERT(termNode->numSuccedents == 0);
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commitNode->succedents[0] = termNode;
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termNode->antecedents[0] = commitNode;
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termNode->antType[0] = rf_control;
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} else {
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/* connecting a nonredundant write DAG */
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/* connect the block node to the commit node */
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RF_ASSERT(blockNode->numSuccedents == 1);
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RF_ASSERT(commitNode->numAntecedents == 1);
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blockNode->succedents[0] = commitNode;
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commitNode->antecedents[0] = blockNode;
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commitNode->antType[0] = rf_control;
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RF_ASSERT(commitNode->numSuccedents == n);
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RF_ASSERT(termNode->numAntecedents == n);
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RF_ASSERT(termNode->numSuccedents == 0);
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for (i = 0; i < n; i++) {
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/* connect the commit node to each write node */
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RF_ASSERT(diskNodes[i].numAntecedents == 1);
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commitNode->succedents[i] = &diskNodes[i];
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diskNodes[i].antecedents[0] = commitNode;
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diskNodes[i].antType[0] = rf_control;
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/* connect each write node to the term node */
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RF_ASSERT(diskNodes[i].numSuccedents == 1);
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diskNodes[i].succedents[0] = termNode;
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termNode->antecedents[i] = &diskNodes[i];
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termNode->antType[i] = rf_control;
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}
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}
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}
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/******************************************************************************
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* Create a fault-free read DAG for RAID level 1
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*
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* Hdr -> Nil -> Rmir -> Cmt -> Trm
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*
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* The "Rmir" node schedules a read from the disk in the mirror pair with the
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* shortest disk queue. the proper queue is selected at Rmir execution. this
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* deferred mapping is unlike other archs in RAIDframe which generally fix
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* mapping at DAG creation time.
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*
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* Parameters: raidPtr - description of the physical array
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* asmap - logical & physical addresses for this access
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* bp - buffer ptr (for holding read data)
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* flags - general flags (e.g. disk locking)
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* allocList - list of memory allocated in DAG creation
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*****************************************************************************/
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static void
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CreateMirrorReadDAG(
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RF_Raid_t * raidPtr,
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RF_AccessStripeMap_t * asmap,
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RF_DagHeader_t * dag_h,
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void *bp,
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RF_RaidAccessFlags_t flags,
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RF_AllocListElem_t * allocList,
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int (*readfunc) (RF_DagNode_t * node))
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{
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RF_DagNode_t *readNodes, *nodes, *blockNode, *commitNode, *termNode;
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RF_PhysDiskAddr_t *data_pda = asmap->physInfo;
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RF_PhysDiskAddr_t *parity_pda = asmap->parityInfo;
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int i, n, totalNumNodes;
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n = asmap->numStripeUnitsAccessed;
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dag_h->creator = "RaidOneReadDAG";
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if (rf_dagDebug) {
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printf("[Creating RAID level 1 read DAG]\n");
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}
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/*
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* This dag can not commit until the commit node is reached
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* errors prior to the commit point imply the dag has failed.
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*/
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dag_h->numCommitNodes = 1;
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dag_h->numCommits = 0;
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dag_h->numSuccedents = 1;
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/*
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* Node count:
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* n data reads
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* 1 block node
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* 1 commit node
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* 1 terminator node
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*/
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RF_ASSERT(n > 0);
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totalNumNodes = n + 3;
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RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t),
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(RF_DagNode_t *), allocList);
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i = 0;
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readNodes = &nodes[i];
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i += n;
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blockNode = &nodes[i];
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i += 1;
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commitNode = &nodes[i];
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i += 1;
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termNode = &nodes[i];
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i += 1;
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RF_ASSERT(i == totalNumNodes);
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/* initialize nodes */
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rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc,
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rf_NullNodeUndoFunc, NULL, n, 0, 0, 0, dag_h, "Nil", allocList);
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rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc,
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rf_NullNodeUndoFunc, NULL, 1, n, 0, 0, dag_h, "Cmt", allocList);
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rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc,
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rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
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for (i = 0; i < n; i++) {
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RF_ASSERT(data_pda != NULL);
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RF_ASSERT(parity_pda != NULL);
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rf_InitNode(&readNodes[i], rf_wait, RF_FALSE, readfunc,
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rf_DiskReadMirrorUndoFunc, rf_GenericWakeupFunc, 1, 1, 5, 0, dag_h,
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"Rmir", allocList);
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readNodes[i].params[0].p = data_pda;
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readNodes[i].params[1].p = data_pda->bufPtr;
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/* parity stripe id is not necessary */
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readNodes[i].params[2].p = 0;
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readNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);
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readNodes[i].params[4].p = parity_pda;
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data_pda = data_pda->next;
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parity_pda = parity_pda->next;
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}
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/*
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* Connect nodes
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*/
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/* connect hdr to block node */
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RF_ASSERT(blockNode->numAntecedents == 0);
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dag_h->succedents[0] = blockNode;
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/* connect block node to read nodes */
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RF_ASSERT(blockNode->numSuccedents == n);
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for (i = 0; i < n; i++) {
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RF_ASSERT(readNodes[i].numAntecedents == 1);
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blockNode->succedents[i] = &readNodes[i];
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readNodes[i].antecedents[0] = blockNode;
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readNodes[i].antType[0] = rf_control;
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}
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/* connect read nodes to commit node */
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RF_ASSERT(commitNode->numAntecedents == n);
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for (i = 0; i < n; i++) {
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RF_ASSERT(readNodes[i].numSuccedents == 1);
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readNodes[i].succedents[0] = commitNode;
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commitNode->antecedents[i] = &readNodes[i];
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commitNode->antType[i] = rf_control;
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}
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/* connect commit node to term node */
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RF_ASSERT(commitNode->numSuccedents == 1);
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RF_ASSERT(termNode->numAntecedents == 1);
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RF_ASSERT(termNode->numSuccedents == 0);
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commitNode->succedents[0] = termNode;
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termNode->antecedents[0] = commitNode;
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termNode->antType[0] = rf_control;
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}
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void
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rf_CreateMirrorIdleReadDAG(
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RF_Raid_t * raidPtr,
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RF_AccessStripeMap_t * asmap,
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RF_DagHeader_t * dag_h,
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void *bp,
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RF_RaidAccessFlags_t flags,
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RF_AllocListElem_t * allocList)
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{
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CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
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rf_DiskReadMirrorIdleFunc);
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}
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void
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rf_CreateMirrorPartitionReadDAG(
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RF_Raid_t * raidPtr,
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RF_AccessStripeMap_t * asmap,
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RF_DagHeader_t * dag_h,
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void *bp,
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RF_RaidAccessFlags_t flags,
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RF_AllocListElem_t * allocList)
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{
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CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
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rf_DiskReadMirrorPartitionFunc);
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}
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