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NetBSD/sys/dev/raidframe/rf_dagffrd.c

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/* $NetBSD: rf_dagffrd.c,v 1.5 2001/10/04 15:58:52 oster Exp $ */
/*
* Copyright (c) 1995 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Mark Holland, Daniel Stodolsky, William V. Courtright II
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* rf_dagffrd.c
*
* code for creating fault-free read DAGs
*
*/
#include <dev/raidframe/raidframevar.h>
#include "rf_raid.h"
#include "rf_dag.h"
#include "rf_dagutils.h"
#include "rf_dagfuncs.h"
#include "rf_debugMem.h"
#include "rf_memchunk.h"
#include "rf_general.h"
#include "rf_dagffrd.h"
/******************************************************************************
*
* General comments on DAG creation:
*
* All DAGs in this file use roll-away error recovery. Each DAG has a single
* commit node, usually called "Cmt." If an error occurs before the Cmt node
* is reached, the execution engine will halt forward execution and work
* backward through the graph, executing the undo functions. Assuming that
* each node in the graph prior to the Cmt node are undoable and atomic - or -
* does not make changes to permanent state, the graph will fail atomically.
* If an error occurs after the Cmt node executes, the engine will roll-forward
* through the graph, blindly executing nodes until it reaches the end.
* If a graph reaches the end, it is assumed to have completed successfully.
*
* A graph has only 1 Cmt node.
*
*/
/******************************************************************************
*
* The following wrappers map the standard DAG creation interface to the
* DAG creation routines. Additionally, these wrappers enable experimentation
* with new DAG structures by providing an extra level of indirection, allowing
* the DAG creation routines to be replaced at this single point.
*/
void
rf_CreateFaultFreeReadDAG(
RF_Raid_t * raidPtr,
RF_AccessStripeMap_t * asmap,
RF_DagHeader_t * dag_h,
void *bp,
RF_RaidAccessFlags_t flags,
RF_AllocListElem_t * allocList)
{
rf_CreateNonredundantDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
RF_IO_TYPE_READ);
}
/******************************************************************************
*
* DAG creation code begins here
*/
/******************************************************************************
*
* creates a DAG to perform a nonredundant read or write of data within one
* stripe.
* For reads, this DAG is as follows:
*
* /---- read ----\
* Header -- Block ---- read ---- Commit -- Terminate
* \---- read ----/
*
* For writes, this DAG is as follows:
*
* /---- write ----\
* Header -- Commit ---- write ---- Block -- Terminate
* \---- write ----/
*
* There is one disk node per stripe unit accessed, and all disk nodes are in
* parallel.
*
* Tricky point here: The first disk node (read or write) is created
* normally. Subsequent disk nodes are created by copying the first one,
* and modifying a few params. The "succedents" and "antecedents" fields are
* _not_ re-created in each node, but rather left pointing to the same array
* that was malloc'd when the first node was created. Thus, it's essential
* that when this DAG is freed, the succedents and antecedents fields be freed
* in ONLY ONE of the read nodes. This does not apply to the "params" field
* because it is recreated for each READ node.
*
* Note that normal-priority accesses do not need to be tagged with their
* parity stripe ID, because they will never be promoted. Hence, I've
* commented-out the code to do this, and marked it with UNNEEDED.
*
*****************************************************************************/
void
rf_CreateNonredundantDAG(
RF_Raid_t * raidPtr,
RF_AccessStripeMap_t * asmap,
RF_DagHeader_t * dag_h,
void *bp,
RF_RaidAccessFlags_t flags,
RF_AllocListElem_t * allocList,
RF_IoType_t type)
{
RF_DagNode_t *nodes, *diskNodes, *blockNode, *commitNode, *termNode;
RF_PhysDiskAddr_t *pda = asmap->physInfo;
int (*doFunc) (RF_DagNode_t *), (*undoFunc) (RF_DagNode_t *);
int i, n, totalNumNodes;
char *name;
n = asmap->numStripeUnitsAccessed;
dag_h->creator = "NonredundantDAG";
RF_ASSERT(RF_IO_IS_R_OR_W(type));
switch (type) {
case RF_IO_TYPE_READ:
doFunc = rf_DiskReadFunc;
undoFunc = rf_DiskReadUndoFunc;
name = "R ";
if (rf_dagDebug)
printf("[Creating non-redundant read DAG]\n");
break;
case RF_IO_TYPE_WRITE:
doFunc = rf_DiskWriteFunc;
undoFunc = rf_DiskWriteUndoFunc;
name = "W ";
if (rf_dagDebug)
printf("[Creating non-redundant write DAG]\n");
break;
default:
RF_PANIC();
}
/*
* For reads, the dag can not commit until the block node is reached.
* for writes, the dag commits immediately.
*/
dag_h->numCommitNodes = 1;
dag_h->numCommits = 0;
dag_h->numSuccedents = 1;
/*
* Node count:
* 1 block node
* n data reads (or writes)
* 1 commit node
* 1 terminator node
*/
RF_ASSERT(n > 0);
totalNumNodes = n + 3;
RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t),
(RF_DagNode_t *), allocList);
i = 0;
diskNodes = &nodes[i];
i += n;
blockNode = &nodes[i];
i += 1;
commitNode = &nodes[i];
i += 1;
termNode = &nodes[i];
i += 1;
RF_ASSERT(i == totalNumNodes);
/* initialize nodes */
switch (type) {
case RF_IO_TYPE_READ:
rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
NULL, n, 0, 0, 0, dag_h, "Nil", allocList);
rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
NULL, 1, n, 0, 0, dag_h, "Cmt", allocList);
rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc,
NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
break;
case RF_IO_TYPE_WRITE:
rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
NULL, 1, 0, 0, 0, dag_h, "Nil", allocList);
rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc, rf_NullNodeUndoFunc,
NULL, n, 1, 0, 0, dag_h, "Cmt", allocList);
rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc,
NULL, 0, n, 0, 0, dag_h, "Trm", allocList);
break;
default:
RF_PANIC();
}
for (i = 0; i < n; i++) {
RF_ASSERT(pda != NULL);
rf_InitNode(&diskNodes[i], rf_wait, RF_FALSE, doFunc, undoFunc, rf_GenericWakeupFunc,
1, 1, 4, 0, dag_h, name, allocList);
diskNodes[i].params[0].p = pda;
diskNodes[i].params[1].p = pda->bufPtr;
/* parity stripe id is not necessary */
diskNodes[i].params[2].v = 0;
diskNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);
pda = pda->next;
}
/*
* Connect nodes.
*/
/* connect hdr to block node */
RF_ASSERT(blockNode->numAntecedents == 0);
dag_h->succedents[0] = blockNode;
if (type == RF_IO_TYPE_READ) {
/* connecting a nonredundant read DAG */
RF_ASSERT(blockNode->numSuccedents == n);
RF_ASSERT(commitNode->numAntecedents == n);
for (i = 0; i < n; i++) {
/* connect block node to each read node */
RF_ASSERT(diskNodes[i].numAntecedents == 1);
blockNode->succedents[i] = &diskNodes[i];
diskNodes[i].antecedents[0] = blockNode;
diskNodes[i].antType[0] = rf_control;
/* connect each read node to the commit node */
RF_ASSERT(diskNodes[i].numSuccedents == 1);
diskNodes[i].succedents[0] = commitNode;
commitNode->antecedents[i] = &diskNodes[i];
commitNode->antType[i] = rf_control;
}
/* connect the commit node to the term node */
RF_ASSERT(commitNode->numSuccedents == 1);
RF_ASSERT(termNode->numAntecedents == 1);
RF_ASSERT(termNode->numSuccedents == 0);
commitNode->succedents[0] = termNode;
termNode->antecedents[0] = commitNode;
termNode->antType[0] = rf_control;
} else {
/* connecting a nonredundant write DAG */
/* connect the block node to the commit node */
RF_ASSERT(blockNode->numSuccedents == 1);
RF_ASSERT(commitNode->numAntecedents == 1);
blockNode->succedents[0] = commitNode;
commitNode->antecedents[0] = blockNode;
commitNode->antType[0] = rf_control;
RF_ASSERT(commitNode->numSuccedents == n);
RF_ASSERT(termNode->numAntecedents == n);
RF_ASSERT(termNode->numSuccedents == 0);
for (i = 0; i < n; i++) {
/* connect the commit node to each write node */
RF_ASSERT(diskNodes[i].numAntecedents == 1);
commitNode->succedents[i] = &diskNodes[i];
diskNodes[i].antecedents[0] = commitNode;
diskNodes[i].antType[0] = rf_control;
/* connect each write node to the term node */
RF_ASSERT(diskNodes[i].numSuccedents == 1);
diskNodes[i].succedents[0] = termNode;
termNode->antecedents[i] = &diskNodes[i];
termNode->antType[i] = rf_control;
}
}
}
/******************************************************************************
* Create a fault-free read DAG for RAID level 1
*
* Hdr -> Nil -> Rmir -> Cmt -> Trm
*
* The "Rmir" node schedules a read from the disk in the mirror pair with the
* shortest disk queue. the proper queue is selected at Rmir execution. this
* deferred mapping is unlike other archs in RAIDframe which generally fix
* mapping at DAG creation time.
*
* Parameters: raidPtr - description of the physical array
* asmap - logical & physical addresses for this access
* bp - buffer ptr (for holding read data)
* flags - general flags (e.g. disk locking)
* allocList - list of memory allocated in DAG creation
*****************************************************************************/
static void
CreateMirrorReadDAG(
RF_Raid_t * raidPtr,
RF_AccessStripeMap_t * asmap,
RF_DagHeader_t * dag_h,
void *bp,
RF_RaidAccessFlags_t flags,
RF_AllocListElem_t * allocList,
int (*readfunc) (RF_DagNode_t * node))
{
RF_DagNode_t *readNodes, *nodes, *blockNode, *commitNode, *termNode;
RF_PhysDiskAddr_t *data_pda = asmap->physInfo;
RF_PhysDiskAddr_t *parity_pda = asmap->parityInfo;
int i, n, totalNumNodes;
n = asmap->numStripeUnitsAccessed;
dag_h->creator = "RaidOneReadDAG";
if (rf_dagDebug) {
printf("[Creating RAID level 1 read DAG]\n");
}
/*
* This dag can not commit until the commit node is reached
* errors prior to the commit point imply the dag has failed.
*/
dag_h->numCommitNodes = 1;
dag_h->numCommits = 0;
dag_h->numSuccedents = 1;
/*
* Node count:
* n data reads
* 1 block node
* 1 commit node
* 1 terminator node
*/
RF_ASSERT(n > 0);
totalNumNodes = n + 3;
RF_CallocAndAdd(nodes, totalNumNodes, sizeof(RF_DagNode_t),
(RF_DagNode_t *), allocList);
i = 0;
readNodes = &nodes[i];
i += n;
blockNode = &nodes[i];
i += 1;
commitNode = &nodes[i];
i += 1;
termNode = &nodes[i];
i += 1;
RF_ASSERT(i == totalNumNodes);
/* initialize nodes */
rf_InitNode(blockNode, rf_wait, RF_FALSE, rf_NullNodeFunc,
rf_NullNodeUndoFunc, NULL, n, 0, 0, 0, dag_h, "Nil", allocList);
rf_InitNode(commitNode, rf_wait, RF_TRUE, rf_NullNodeFunc,
rf_NullNodeUndoFunc, NULL, 1, n, 0, 0, dag_h, "Cmt", allocList);
rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc,
rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", allocList);
for (i = 0; i < n; i++) {
RF_ASSERT(data_pda != NULL);
RF_ASSERT(parity_pda != NULL);
rf_InitNode(&readNodes[i], rf_wait, RF_FALSE, readfunc,
rf_DiskReadMirrorUndoFunc, rf_GenericWakeupFunc, 1, 1, 5, 0, dag_h,
"Rmir", allocList);
readNodes[i].params[0].p = data_pda;
readNodes[i].params[1].p = data_pda->bufPtr;
/* parity stripe id is not necessary */
readNodes[i].params[2].p = 0;
readNodes[i].params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);
readNodes[i].params[4].p = parity_pda;
data_pda = data_pda->next;
parity_pda = parity_pda->next;
}
/*
* Connect nodes
*/
/* connect hdr to block node */
RF_ASSERT(blockNode->numAntecedents == 0);
dag_h->succedents[0] = blockNode;
/* connect block node to read nodes */
RF_ASSERT(blockNode->numSuccedents == n);
for (i = 0; i < n; i++) {
RF_ASSERT(readNodes[i].numAntecedents == 1);
blockNode->succedents[i] = &readNodes[i];
readNodes[i].antecedents[0] = blockNode;
readNodes[i].antType[0] = rf_control;
}
/* connect read nodes to commit node */
RF_ASSERT(commitNode->numAntecedents == n);
for (i = 0; i < n; i++) {
RF_ASSERT(readNodes[i].numSuccedents == 1);
readNodes[i].succedents[0] = commitNode;
commitNode->antecedents[i] = &readNodes[i];
commitNode->antType[i] = rf_control;
}
/* connect commit node to term node */
RF_ASSERT(commitNode->numSuccedents == 1);
RF_ASSERT(termNode->numAntecedents == 1);
RF_ASSERT(termNode->numSuccedents == 0);
commitNode->succedents[0] = termNode;
termNode->antecedents[0] = commitNode;
termNode->antType[0] = rf_control;
}
void
rf_CreateMirrorIdleReadDAG(
RF_Raid_t * raidPtr,
RF_AccessStripeMap_t * asmap,
RF_DagHeader_t * dag_h,
void *bp,
RF_RaidAccessFlags_t flags,
RF_AllocListElem_t * allocList)
{
CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
rf_DiskReadMirrorIdleFunc);
}
void
rf_CreateMirrorPartitionReadDAG(
RF_Raid_t * raidPtr,
RF_AccessStripeMap_t * asmap,
RF_DagHeader_t * dag_h,
void *bp,
RF_RaidAccessFlags_t flags,
RF_AllocListElem_t * allocList)
{
CreateMirrorReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
rf_DiskReadMirrorPartitionFunc);
}
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