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Initial revision

/*	$OpenBSD: rf_paritylogDiskMgr.c,v 1.6 2002/12/16 07:01:04 tdeval Exp $	*/
/*	$NetBSD: rf_paritylogDiskMgr.c,v 1.10 2000/01/15 01:57:57 oster Exp $	*/

/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: 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.
 */
/*
 * Code for flushing and reintegrating operations related to parity logging.
 */

#include "rf_archs.h"

#if	RF_INCLUDE_PARITYLOGGING > 0

#include "rf_types.h"
#include "rf_threadstuff.h"
#include "rf_mcpair.h"
#include "rf_raid.h"
#include "rf_dag.h"
#include "rf_dagfuncs.h"
#include "rf_desc.h"
#include "rf_layout.h"
#include "rf_diskqueue.h"
#include "rf_paritylog.h"
#include "rf_general.h"
#include "rf_etimer.h"
#include "rf_paritylogging.h"
#include "rf_engine.h"
#include "rf_dagutils.h"
#include "rf_map.h"
#include "rf_parityscan.h"

#include "rf_paritylogDiskMgr.h"

caddr_t rf_AcquireReintBuffer(RF_RegionBufferQueue_t *);
void rf_ReleaseReintBuffer(RF_RegionBufferQueue_t *, caddr_t);
void rf_ReadRegionLog(RF_RegionId_t, RF_MCPair_t *, caddr_t, RF_Raid_t *,
	RF_DagHeader_t **, RF_AllocListElem_t **, RF_PhysDiskAddr_t **);
void rf_WriteCoreLog(RF_ParityLog_t *, RF_MCPair_t *, RF_Raid_t *,
	RF_DagHeader_t **, RF_AllocListElem_t **, RF_PhysDiskAddr_t **);
void rf_ReadRegionParity(RF_RegionId_t, RF_MCPair_t *, caddr_t, RF_Raid_t *,
	RF_DagHeader_t **, RF_AllocListElem_t **, RF_PhysDiskAddr_t **);
void rf_WriteRegionParity(RF_RegionId_t, RF_MCPair_t *, caddr_t, RF_Raid_t *,
	RF_DagHeader_t **, RF_AllocListElem_t **, RF_PhysDiskAddr_t **);
void rf_FlushLogsToDisk(RF_Raid_t *, RF_ParityLog_t *);
void rf_ReintegrateRegion(RF_Raid_t *, RF_RegionId_t, RF_ParityLog_t *);
void rf_ReintegrateLogs(RF_Raid_t *, RF_ParityLog_t *);


caddr_t
rf_AcquireReintBuffer(RF_RegionBufferQueue_t *pool)
{
	caddr_t bufPtr = NULL;

	/*
	 * Return a region buffer from the free list (pool). If the free list
	 * is empty, WAIT. BLOCKING
	 */

	RF_LOCK_MUTEX(pool->mutex);
	if (pool->availableBuffers > 0) {
		bufPtr = pool->buffers[pool->availBuffersIndex];
		pool->availableBuffers--;
		pool->availBuffersIndex++;
		if (pool->availBuffersIndex == pool->totalBuffers)
			pool->availBuffersIndex = 0;
		RF_UNLOCK_MUTEX(pool->mutex);
	} else {
		RF_PANIC();	/*
				 * Should never happen in correct config,
				 * single reint.
				 */
		RF_WAIT_COND(pool->cond, pool->mutex);
	}
	return (bufPtr);
}


void
rf_ReleaseReintBuffer(RF_RegionBufferQueue_t *pool, caddr_t bufPtr)
{
	/*
	 * Insert a region buffer (bufPtr) into the free list (pool).
	 * NON-BLOCKING
	 */

	RF_LOCK_MUTEX(pool->mutex);
	pool->availableBuffers++;
	pool->buffers[pool->emptyBuffersIndex] = bufPtr;
	pool->emptyBuffersIndex++;
	if (pool->emptyBuffersIndex == pool->totalBuffers)
		pool->emptyBuffersIndex = 0;
	RF_ASSERT(pool->availableBuffers <= pool->totalBuffers);
	RF_UNLOCK_MUTEX(pool->mutex);
	RF_SIGNAL_COND(pool->cond);
}


void
rf_ReadRegionLog(RF_RegionId_t regionID, RF_MCPair_t *rrd_mcpair,
    caddr_t regionBuffer, RF_Raid_t *raidPtr, RF_DagHeader_t **rrd_dag_h,
    RF_AllocListElem_t **rrd_alloclist, RF_PhysDiskAddr_t **rrd_pda)
{
	/*
	 * Initiate the read a region log from disk. Once initiated, return
	 * to the calling routine.
	 *
	 * NON-BLOCKING
	 */

	RF_AccTraceEntry_t *tracerec;
	RF_DagNode_t *rrd_rdNode;

	/* Create DAG to read region log from disk. */
	rf_MakeAllocList(*rrd_alloclist);
	*rrd_dag_h = rf_MakeSimpleDAG(raidPtr, 1, 0, regionBuffer,
	    rf_DiskReadFunc, rf_DiskReadUndoFunc, "Rrl", *rrd_alloclist,
	    RF_DAG_FLAGS_NONE, RF_IO_NORMAL_PRIORITY);

	/* Create and initialize PDA for the core log. */
	/* RF_Malloc(*rrd_pda, sizeof(RF_PhysDiskAddr_t),
	 * (RF_PhysDiskAddr_t *)); */
	*rrd_pda = rf_AllocPDAList(1);
	rf_MapLogParityLogging(raidPtr, regionID, 0, &((*rrd_pda)->row),
	    &((*rrd_pda)->col), &((*rrd_pda)->startSector));
	(*rrd_pda)->numSector = raidPtr->regionInfo[regionID].capacity;

	if ((*rrd_pda)->next) {
		(*rrd_pda)->next = NULL;
		printf("set rrd_pda->next to NULL\n");
	}
	/* Initialize DAG parameters. */
	RF_Malloc(tracerec, sizeof(RF_AccTraceEntry_t), (RF_AccTraceEntry_t *));
	bzero((char *) tracerec, sizeof(RF_AccTraceEntry_t));
	(*rrd_dag_h)->tracerec = tracerec;
	rrd_rdNode = (*rrd_dag_h)->succedents[0]->succedents[0];
	rrd_rdNode->params[0].p = *rrd_pda;
	/* rrd_rdNode->params[1] = regionBuffer; */
	rrd_rdNode->params[2].v = 0;
	rrd_rdNode->params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY,
						   0, 0, 0);

	/* Launch region log read dag. */
	rf_DispatchDAG(*rrd_dag_h, (void (*) (void *)) rf_MCPairWakeupFunc,
	    (void *) rrd_mcpair);
}


void
rf_WriteCoreLog(RF_ParityLog_t *log, RF_MCPair_t *fwr_mcpair,
    RF_Raid_t *raidPtr, RF_DagHeader_t **fwr_dag_h,
    RF_AllocListElem_t **fwr_alloclist, RF_PhysDiskAddr_t **fwr_pda)
{
	RF_RegionId_t regionID = log->regionID;
	RF_AccTraceEntry_t *tracerec;
	RF_SectorNum_t regionOffset;
	RF_DagNode_t *fwr_wrNode;

	/*
	 * Initiate the write of a core log to a region log disk. Once
	 * initiated, return to the calling routine.
	 *
	 * NON-BLOCKING
	 */

	/* Create DAG to write a core log to a region log disk. */
	rf_MakeAllocList(*fwr_alloclist);
	*fwr_dag_h = rf_MakeSimpleDAG(raidPtr, 1, 0, log->bufPtr,
	    rf_DiskWriteFunc, rf_DiskWriteUndoFunc, "Wcl", *fwr_alloclist,
	    RF_DAG_FLAGS_NONE, RF_IO_NORMAL_PRIORITY);

	/* Create and initialize PDA for the region log. */
	/* RF_Malloc(*fwr_pda, sizeof(RF_PhysDiskAddr_t),
	 * (RF_PhysDiskAddr_t *)); */
	*fwr_pda = rf_AllocPDAList(1);
	regionOffset = log->diskOffset;
	rf_MapLogParityLogging(raidPtr, regionID, regionOffset,
	    &((*fwr_pda)->row), &((*fwr_pda)->col), &((*fwr_pda)->startSector));
	(*fwr_pda)->numSector = raidPtr->numSectorsPerLog;

	/* Initialize DAG parameters. */
	RF_Malloc(tracerec, sizeof(RF_AccTraceEntry_t), (RF_AccTraceEntry_t *));
	bzero((char *) tracerec, sizeof(RF_AccTraceEntry_t));
	(*fwr_dag_h)->tracerec = tracerec;
	fwr_wrNode = (*fwr_dag_h)->succedents[0]->succedents[0];
	fwr_wrNode->params[0].p = *fwr_pda;
	/* fwr_wrNode->params[1] = log->bufPtr; */
	fwr_wrNode->params[2].v = 0;
	fwr_wrNode->params[3].v =
	    RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);

	/* Launch the dag to write the core log to disk. */
	rf_DispatchDAG(*fwr_dag_h, (void (*) (void *)) rf_MCPairWakeupFunc,
	    (void *) fwr_mcpair);
}


void
rf_ReadRegionParity(RF_RegionId_t regionID, RF_MCPair_t *prd_mcpair,
    caddr_t parityBuffer, RF_Raid_t *raidPtr, RF_DagHeader_t **prd_dag_h,
    RF_AllocListElem_t **prd_alloclist, RF_PhysDiskAddr_t **prd_pda)
{
	/*
	 * Initiate the read region parity from disk. Once initiated, return
	 * to the calling routine.
	 *
	 * NON-BLOCKING
	 */

	RF_AccTraceEntry_t *tracerec;
	RF_DagNode_t *prd_rdNode;

	/* Create DAG to read region parity from disk. */
	rf_MakeAllocList(*prd_alloclist);
	*prd_dag_h = rf_MakeSimpleDAG(raidPtr, 1, 0, NULL, rf_DiskReadFunc,
	    rf_DiskReadUndoFunc, "Rrp", *prd_alloclist, RF_DAG_FLAGS_NONE,
	    RF_IO_NORMAL_PRIORITY);

	/* Create and initialize PDA for region parity. */
	/* RF_Malloc(*prd_pda, sizeof(RF_PhysDiskAddr_t),
	 * (RF_PhysDiskAddr_t *)); */
	*prd_pda = rf_AllocPDAList(1);
	rf_MapRegionParity(raidPtr, regionID, &((*prd_pda)->row),
	    &((*prd_pda)->col), &((*prd_pda)->startSector),
	    &((*prd_pda)->numSector));
	if (rf_parityLogDebug)
		printf("[reading %d sectors of parity from region %d]\n",
		    (int) (*prd_pda)->numSector, regionID);
	if ((*prd_pda)->next) {
		(*prd_pda)->next = NULL;
		printf("set prd_pda->next to NULL\n");
	}
	/* Initialize DAG parameters. */
	RF_Malloc(tracerec, sizeof(RF_AccTraceEntry_t), (RF_AccTraceEntry_t *));
	bzero((char *) tracerec, sizeof(RF_AccTraceEntry_t));
	(*prd_dag_h)->tracerec = tracerec;
	prd_rdNode = (*prd_dag_h)->succedents[0]->succedents[0];
	prd_rdNode->params[0].p = *prd_pda;
	prd_rdNode->params[1].p = parityBuffer;
	prd_rdNode->params[2].v = 0;
	prd_rdNode->params[3].v =
	    RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);
	if (rf_validateDAGDebug)
		rf_ValidateDAG(*prd_dag_h);
	/* Launch region parity read dag. */
	rf_DispatchDAG(*prd_dag_h, (void (*) (void *)) rf_MCPairWakeupFunc,
	    (void *) prd_mcpair);
}

void
rf_WriteRegionParity(RF_RegionId_t regionID, RF_MCPair_t *pwr_mcpair,
    caddr_t parityBuffer, RF_Raid_t *raidPtr, RF_DagHeader_t **pwr_dag_h,
    RF_AllocListElem_t **pwr_alloclist, RF_PhysDiskAddr_t **pwr_pda)
{
	/*
	 * Initiate the write of region parity to disk. Once initiated, return
	 * to the calling routine.
	 *
	 * NON-BLOCKING
	 */

	RF_AccTraceEntry_t *tracerec;
	RF_DagNode_t *pwr_wrNode;

	/* Create DAG to write region log from disk. */
	rf_MakeAllocList(*pwr_alloclist);
	*pwr_dag_h = rf_MakeSimpleDAG(raidPtr, 1, 0, parityBuffer,
	    rf_DiskWriteFunc, rf_DiskWriteUndoFunc, "Wrp", *pwr_alloclist,
	    RF_DAG_FLAGS_NONE, RF_IO_NORMAL_PRIORITY);

	/* Create and initialize PDA for region parity. */
	/* RF_Malloc(*pwr_pda, sizeof(RF_PhysDiskAddr_t),
	 * (RF_PhysDiskAddr_t *)); */
	*pwr_pda = rf_AllocPDAList(1);
	rf_MapRegionParity(raidPtr, regionID, &((*pwr_pda)->row),
	    &((*pwr_pda)->col), &((*pwr_pda)->startSector),
	    &((*pwr_pda)->numSector));

	/* Initialize DAG parameters. */
	RF_Malloc(tracerec, sizeof(RF_AccTraceEntry_t), (RF_AccTraceEntry_t *));
	bzero((char *) tracerec, sizeof(RF_AccTraceEntry_t));
	(*pwr_dag_h)->tracerec = tracerec;
	pwr_wrNode = (*pwr_dag_h)->succedents[0]->succedents[0];
	pwr_wrNode->params[0].p = *pwr_pda;
	/* pwr_wrNode->params[1] = parityBuffer; */
	pwr_wrNode->params[2].v = 0;
	pwr_wrNode->params[3].v =
	    RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, 0);

	/* Launch the dag to write region parity to disk. */
	rf_DispatchDAG(*pwr_dag_h, (void (*) (void *)) rf_MCPairWakeupFunc,
	    (void *) pwr_mcpair);
}

void
rf_FlushLogsToDisk(RF_Raid_t *raidPtr, RF_ParityLog_t *logList)
{
	/*
	 * Flush a linked list of core logs to the log disk. Logs contain the
	 * disk location where they should be written. Logs were written in
	 * FIFO order and that order must be preserved.
	 *
	 * Recommended optimizations:
	 * 1) Allow multiple flushes to occur simultaneously.
	 * 2) Coalesce contiguous flush operations.
	 *
	 * BLOCKING
	 */

	RF_ParityLog_t *log;
	RF_RegionId_t regionID;
	RF_MCPair_t *fwr_mcpair;
	RF_DagHeader_t *fwr_dag_h;
	RF_AllocListElem_t *fwr_alloclist;
	RF_PhysDiskAddr_t *fwr_pda;

	fwr_mcpair = rf_AllocMCPair();
	RF_LOCK_MUTEX(fwr_mcpair->mutex);

	RF_ASSERT(logList);
	log = logList;
	while (log) {
		regionID = log->regionID;

		/* Create and launch a DAG to write the core log. */
		if (rf_parityLogDebug)
			printf("[initiating write of core log for region"
			    " %d]\n", regionID);
		fwr_mcpair->flag = RF_FALSE;
		rf_WriteCoreLog(log, fwr_mcpair, raidPtr, &fwr_dag_h,
		    &fwr_alloclist, &fwr_pda);

		/* Wait for the DAG to complete. */
		while (!fwr_mcpair->flag)
			RF_WAIT_COND(fwr_mcpair->cond, fwr_mcpair->mutex);
		if (fwr_dag_h->status != rf_enable) {
			RF_ERRORMSG1("Unable to write core log to disk"
			    " (region %d)\n", regionID);
			RF_ASSERT(0);
		}
		/* RF_Free(fwr_pda, sizeof(RF_PhysDiskAddr_t)); */
		rf_FreePhysDiskAddr(fwr_pda);
		rf_FreeDAG(fwr_dag_h);
		rf_FreeAllocList(fwr_alloclist);

		log = log->next;
	}
	RF_UNLOCK_MUTEX(fwr_mcpair->mutex);
	rf_FreeMCPair(fwr_mcpair);
	rf_ReleaseParityLogs(raidPtr, logList);
}

void
rf_ReintegrateRegion(RF_Raid_t *raidPtr, RF_RegionId_t regionID,
    RF_ParityLog_t *coreLog)
{
	RF_MCPair_t *rrd_mcpair = NULL, *prd_mcpair, *pwr_mcpair;
	RF_DagHeader_t *rrd_dag_h, *prd_dag_h, *pwr_dag_h;
	RF_AllocListElem_t *rrd_alloclist, *prd_alloclist, *pwr_alloclist;
	RF_PhysDiskAddr_t *rrd_pda, *prd_pda, *pwr_pda;
	caddr_t parityBuffer, regionBuffer = NULL;

	/*
	 * Reintegrate a region (regionID).
	 *
	 * 1. Acquire region and parity buffers.
	 * 2. Read log from disk.
	 * 3. Read parity from disk.
	 * 4. Apply log to parity.
	 * 5. Apply core log to parity.
	 * 6. Write new parity to disk.
	 *
	 * BLOCKING
	 */

	if (rf_parityLogDebug)
		printf("[reintegrating region %d]\n", regionID);

	/* Initiate read of region parity. */
	if (rf_parityLogDebug)
		printf("[initiating read of parity for region %d]\n", regionID);
	parityBuffer = rf_AcquireReintBuffer(&raidPtr->parityBufferPool);
	prd_mcpair = rf_AllocMCPair();
	RF_LOCK_MUTEX(prd_mcpair->mutex);
	prd_mcpair->flag = RF_FALSE;
	rf_ReadRegionParity(regionID, prd_mcpair, parityBuffer, raidPtr,
			 &prd_dag_h, &prd_alloclist, &prd_pda);

	/* If region log nonempty, initiate read. */
	if (raidPtr->regionInfo[regionID].diskCount > 0) {
		if (rf_parityLogDebug)
			printf("[initiating read of disk log for region %d]\n",
			    regionID);
		regionBuffer =
		    rf_AcquireReintBuffer(&raidPtr->regionBufferPool);
		rrd_mcpair = rf_AllocMCPair();
		RF_LOCK_MUTEX(rrd_mcpair->mutex);
		rrd_mcpair->flag = RF_FALSE;
		rf_ReadRegionLog(regionID, rrd_mcpair, regionBuffer, raidPtr,
		    &rrd_dag_h, &rrd_alloclist, &rrd_pda);
	}
	/* Wait on read of region parity to complete. */
	while (!prd_mcpair->flag) {
		RF_WAIT_COND(prd_mcpair->cond, prd_mcpair->mutex);
	}
	RF_UNLOCK_MUTEX(prd_mcpair->mutex);
	if (prd_dag_h->status != rf_enable) {
		RF_ERRORMSG("Unable to read parity from disk\n");
		/* Add code to fail the parity disk. */
		RF_ASSERT(0);
	}
	/* Apply core log to parity. */
	/* if (coreLog) ApplyLogsToParity(coreLog, parityBuffer); */

	if (raidPtr->regionInfo[regionID].diskCount > 0) {
		/* Wait on read of region log to complete. */
		while (!rrd_mcpair->flag)
			RF_WAIT_COND(rrd_mcpair->cond, rrd_mcpair->mutex);
		RF_UNLOCK_MUTEX(rrd_mcpair->mutex);
		if (rrd_dag_h->status != rf_enable) {
			RF_ERRORMSG("Unable to read region log from disk\n");
			/* Add code to fail the log disk. */
			RF_ASSERT(0);
		}
		/* Apply region log to parity. */
		/* ApplyRegionToParity(regionID, regionBuffer, parityBuffer); */
		/* Release resources associated with region log. */
		/* RF_Free(rrd_pda, sizeof(RF_PhysDiskAddr_t)); */
		rf_FreePhysDiskAddr(rrd_pda);
		rf_FreeDAG(rrd_dag_h);
		rf_FreeAllocList(rrd_alloclist);
		rf_FreeMCPair(rrd_mcpair);
		rf_ReleaseReintBuffer(&raidPtr->regionBufferPool, regionBuffer);
	}
	/* Write reintegrated parity to disk. */
	if (rf_parityLogDebug)
		printf("[initiating write of parity for region %d]\n",
		    regionID);
	pwr_mcpair = rf_AllocMCPair();
	RF_LOCK_MUTEX(pwr_mcpair->mutex);
	pwr_mcpair->flag = RF_FALSE;
	rf_WriteRegionParity(regionID, pwr_mcpair, parityBuffer, raidPtr,
	    &pwr_dag_h, &pwr_alloclist, &pwr_pda);
	while (!pwr_mcpair->flag)
		RF_WAIT_COND(pwr_mcpair->cond, pwr_mcpair->mutex);
	RF_UNLOCK_MUTEX(pwr_mcpair->mutex);
	if (pwr_dag_h->status != rf_enable) {
		RF_ERRORMSG("Unable to write parity to disk\n");
		/* Add code to fail the parity disk. */
		RF_ASSERT(0);
	}
	/* Release resources associated with read of old parity. */
	/* RF_Free(prd_pda, sizeof(RF_PhysDiskAddr_t)); */
	rf_FreePhysDiskAddr(prd_pda);
	rf_FreeDAG(prd_dag_h);
	rf_FreeAllocList(prd_alloclist);
	rf_FreeMCPair(prd_mcpair);

	/* Release resources associated with write of new parity. */
	rf_ReleaseReintBuffer(&raidPtr->parityBufferPool, parityBuffer);
	/* RF_Free(pwr_pda, sizeof(RF_PhysDiskAddr_t)); */
	rf_FreePhysDiskAddr(pwr_pda);
	rf_FreeDAG(pwr_dag_h);
	rf_FreeAllocList(pwr_alloclist);
	rf_FreeMCPair(pwr_mcpair);

	if (rf_parityLogDebug)
		printf("[finished reintegrating region %d]\n", regionID);
}


void
rf_ReintegrateLogs(RF_Raid_t *raidPtr, RF_ParityLog_t *logList)
{
	RF_ParityLog_t *log, *freeLogList = NULL;
	RF_ParityLogData_t *logData, *logDataList;
	RF_RegionId_t regionID;

	RF_ASSERT(logList);
	while (logList) {
		log = logList;
		logList = logList->next;
		log->next = NULL;
		regionID = log->regionID;
		rf_ReintegrateRegion(raidPtr, regionID, log);
		log->numRecords = 0;

		/*
		 * Remove all items which are blocked on reintegration of this
		 * region.
		 */
		RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
		logData = rf_SearchAndDequeueParityLogData(raidPtr, regionID,
		    &raidPtr->parityLogDiskQueue.reintBlockHead,
		    &raidPtr->parityLogDiskQueue.reintBlockTail, RF_TRUE);
		logDataList = logData;
		while (logData) {
			logData->next =
			    rf_SearchAndDequeueParityLogData(raidPtr, regionID,
			     &raidPtr->parityLogDiskQueue.reintBlockHead,
			     &raidPtr->parityLogDiskQueue.reintBlockTail,
			     RF_TRUE);
			logData = logData->next;
		}
		RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);

		/*
		 * Process blocked log data and clear reintInProgress flag for
		 * this region.
		 */
		if (logDataList)
			rf_ParityLogAppend(logDataList, RF_TRUE, &log, RF_TRUE);
		else {
			/*
			 * Enable flushing for this region. Holding both
			 * locks provides a synchronization barrier with
			 * DumpParityLogToDisk.
			 */
			RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
			RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].reintMutex);
			RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
			raidPtr->regionInfo[regionID].diskCount = 0;
			raidPtr->regionInfo[regionID].reintInProgress =
			    RF_FALSE;
			RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
			RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID]
			    .reintMutex);	/* Flushing is now enabled. */
			RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
		}
		/*
		 * If log wasn't used, attach it to the list of logs to be
		 * returned.
		 */
		if (log) {
			log->next = freeLogList;
			freeLogList = log;
		}
	}
	if (freeLogList)
		rf_ReleaseParityLogs(raidPtr, freeLogList);
}

int
rf_ShutdownLogging(RF_Raid_t *raidPtr)
{
	/*
	 * Shutdown parity logging:
	 * 1) Disable parity logging in all regions.
	 * 2) Reintegrate all regions.
	 */

	RF_SectorCount_t diskCount;
	RF_RegionId_t regionID;
	RF_ParityLog_t *log;

	if (rf_parityLogDebug)
		printf("[shutting down parity logging]\n");
	/*
	 * Since parity log maps are volatile, we must reintegrate all
	 * regions.
	 */
	if (rf_forceParityLogReint) {
		for (regionID = 0; regionID < rf_numParityRegions; regionID++) {
			RF_LOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
			raidPtr->regionInfo[regionID].loggingEnabled = RF_FALSE;
			log = raidPtr->regionInfo[regionID].coreLog;
			raidPtr->regionInfo[regionID].coreLog = NULL;
			diskCount = raidPtr->regionInfo[regionID].diskCount;
			RF_UNLOCK_MUTEX(raidPtr->regionInfo[regionID].mutex);
			if (diskCount > 0 || log != NULL)
				rf_ReintegrateRegion(raidPtr, regionID, log);
			if (log != NULL)
				rf_ReleaseParityLogs(raidPtr, log);
		}
	}
	if (rf_parityLogDebug) {
		printf("[parity logging disabled]\n");
		printf("[should be done !]\n");
	}
	return (0);
}

int
rf_ParityLoggingDiskManager(RF_Raid_t *raidPtr)
{
	RF_ParityLog_t *reintQueue, *flushQueue;
	int workNeeded, done = RF_FALSE;
	int s;

	/*
	 * Main program for parity logging disk thread. This routine waits
	 * for work to appear in either the flush or reintegration queues and
	 * is responsible for flushing core logs to the log disk as well as
	 * reintegrating parity regions.
	 *
	 * BLOCKING
	 */

	s = splbio();

	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);

	/*
	 * Inform our creator that we're running. Don't bother doing the
	 * mutex lock/unlock dance: we locked above, and we'll unlock
	 * below with nothing to do, yet.
	 */
	raidPtr->parityLogDiskQueue.threadState |= RF_PLOG_RUNNING;
	RF_SIGNAL_COND(raidPtr->parityLogDiskQueue.cond);

	/* Empty the work queues. */
	flushQueue = raidPtr->parityLogDiskQueue.flushQueue;
	raidPtr->parityLogDiskQueue.flushQueue = NULL;
	reintQueue = raidPtr->parityLogDiskQueue.reintQueue;
	raidPtr->parityLogDiskQueue.reintQueue = NULL;
	workNeeded = (flushQueue || reintQueue);

	while (!done) {
		while (workNeeded) {
			/*
			 * First, flush all logs in the flush queue, freeing
			 * buffers. Second, reintegrate all regions that are
			 * reported as full. Third, append queued log data
			 * until blocked.
			 *
			 * Note: Incoming appends (ParityLogAppend) can block
			 * on either 1. empty buffer pool 2. region under
			 * reintegration. To preserve a global FIFO ordering of
			 * appends, buffers are not released to the world
			 * until those appends blocked on buffers are removed
			 * from the append queue. Similarly, regions that are
			 * reintegrated are not opened for general use until
			 * the append queue has been emptied.
			 */

			RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);

			/*
			 * Empty flushQueue, using free'd log buffers to
			 * process bufTail.
			 */
			if (flushQueue)
				rf_FlushLogsToDisk(raidPtr, flushQueue);

			/*
			 * Empty reintQueue, flushing from reintTail as we go.
			 */
			if (reintQueue)
				rf_ReintegrateLogs(raidPtr, reintQueue);

			RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
			flushQueue = raidPtr->parityLogDiskQueue.flushQueue;
			raidPtr->parityLogDiskQueue.flushQueue = NULL;
			reintQueue = raidPtr->parityLogDiskQueue.reintQueue;
			raidPtr->parityLogDiskQueue.reintQueue = NULL;
			workNeeded = (flushQueue || reintQueue);
		}
		/* No work is needed at this point. */
		if (raidPtr->parityLogDiskQueue.threadState & RF_PLOG_TERMINATE) {
			/*
			 * Shutdown parity logging:
			 * 1. Disable parity logging in all regions.
			 * 2. Reintegrate all regions.
			 */
			done = RF_TRUE;	/* Thread disabled, no work needed. */
			RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
			rf_ShutdownLogging(raidPtr);
		}
		if (!done) {
			/* Thread enabled, no work needed, so sleep. */
			if (rf_parityLogDebug)
				printf("[parity logging disk manager"
				    " sleeping]\n");
			RF_WAIT_COND(raidPtr->parityLogDiskQueue.cond,
			    raidPtr->parityLogDiskQueue.mutex);
			if (rf_parityLogDebug)
				printf("[parity logging disk manager just"
				    " woke up]\n");
			flushQueue = raidPtr->parityLogDiskQueue.flushQueue;
			raidPtr->parityLogDiskQueue.flushQueue = NULL;
			reintQueue = raidPtr->parityLogDiskQueue.reintQueue;
			raidPtr->parityLogDiskQueue.reintQueue = NULL;
			workNeeded = (flushQueue || reintQueue);
		}
	}
	/*
	 * Announce that we're done.
	 */
	RF_LOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
	raidPtr->parityLogDiskQueue.threadState |= RF_PLOG_SHUTDOWN;
	RF_UNLOCK_MUTEX(raidPtr->parityLogDiskQueue.mutex);
	RF_SIGNAL_COND(raidPtr->parityLogDiskQueue.cond);

	splx(s);

	/*
	 * In the Net- & OpenBSD kernel, the thread must exit; returning would
	 * cause the proc trampoline to attempt to return to userspace.
	 */
	kthread_exit(0);	/* does not return */
}
#endif	/* RF_INCLUDE_PARITYLOGGING > 0 */