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Initial revision

/*	$OpenBSD: rf_reconmap.c,v 1.4 2002/12/16 07:01:05 tdeval Exp $	*/
/*	$NetBSD: rf_reconmap.c,v 1.6 1999/08/14 21:44:24 oster Exp $	*/

/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Mark Holland
 *
 * 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_reconmap.c
 *
 * Code to maintain a map of what sectors have/have not been reconstructed.
 *
 *****************************************************************************/

#include "rf_raid.h"
#include <sys/time.h>
#include "rf_general.h"
#include "rf_utils.h"

/*
 * Special pointer values indicating that a reconstruction unit
 * has been either totally reconstructed or not at all. Both
 * are illegal pointer values, so you have to be careful not to
 * dereference through them. RU_NOTHING must be zero, since
 * MakeReconMap uses bzero to initialize the structure. These are used
 * only at the head of the list.
 */
#define	RU_ALL		((RF_ReconMapListElem_t *) -1)
#define	RU_NOTHING	((RF_ReconMapListElem_t *) 0)

/* Used to mark the end of the list. */
#define	RU_NIL		((RF_ReconMapListElem_t *) 0)


void rf_compact_stat_entry(RF_Raid_t *, RF_ReconMap_t *, int);
void rf_crunch_list(RF_ReconMap_t *, RF_ReconMapListElem_t *);
RF_ReconMapListElem_t * rf_MakeReconMapListElem(RF_SectorNum_t, RF_SectorNum_t,
	RF_ReconMapListElem_t *);
void rf_FreeReconMapListElem(RF_ReconMap_t *, RF_ReconMapListElem_t *);
void rf_update_size(RF_ReconMap_t *, int);
void rf_PrintList(RF_ReconMapListElem_t *);


/*****************************************************************************
 *
 * Creates and initializes new Reconstruction map.
 *
 *****************************************************************************/

RF_ReconMap_t *
rf_MakeReconMap(
    RF_Raid_t		*raidPtr,
    RF_SectorCount_t	 ru_sectors,		/*
						 * Size of reconstruction unit
						 * in sectors.
						 */
    RF_SectorCount_t	 disk_sectors,		/* Size of disk in sectors. */
    RF_ReconUnitCount_t	 spareUnitsPerDisk	/*
						 * Zero unless distributed
						 * sparing.
						 */
)
{
	RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
	RF_ReconUnitCount_t num_rus = layoutPtr->stripeUnitsPerDisk /
	    layoutPtr->SUsPerRU;
	RF_ReconMap_t *p;
	int rc;

	RF_Malloc(p, sizeof(RF_ReconMap_t), (RF_ReconMap_t *));
	p->sectorsPerReconUnit = ru_sectors;
	p->sectorsInDisk = disk_sectors;

	p->totalRUs = num_rus;
	p->spareRUs = spareUnitsPerDisk;
	p->unitsLeft = num_rus - spareUnitsPerDisk;

	RF_Malloc(p->status, num_rus * sizeof(RF_ReconMapListElem_t *),
	    (RF_ReconMapListElem_t **));
	RF_ASSERT(p->status != (RF_ReconMapListElem_t **) NULL);

	(void) bzero((char *) p->status, num_rus *
	    sizeof(RF_ReconMapListElem_t *));

	p->size = sizeof(RF_ReconMap_t) + num_rus *
	    sizeof(RF_ReconMapListElem_t *);
	p->maxSize = p->size;

	rc = rf_mutex_init(&p->mutex);
	if (rc) {
		RF_ERRORMSG3("Unable to init mutex file %s line %d rc=%d.\n",
		    __FILE__, __LINE__, rc);
		RF_Free(p->status, num_rus * sizeof(RF_ReconMapListElem_t *));
		RF_Free(p, sizeof(RF_ReconMap_t));
		return (NULL);
	}
	return (p);
}


/*****************************************************************************
 *
 * Marks a new set of sectors as reconstructed. All the possible mergings get
 * complicated. To simplify matters, the approach I take is to just dump
 * something into the list, and then clean it up (i.e. merge elements and
 * eliminate redundant ones) in a second pass over the list
 * (rf_compact_stat_entry()).
 * Not 100% efficient, since a structure can be allocated and then immediately
 * freed, but it keeps this code from becoming (more of) a nightmare of
 * special cases. The only thing that rf_compact_stat_entry() assumes is that
 * the list is sorted by startSector, and so this is the only condition I
 * maintain here. (MCH)
 *
 *****************************************************************************/

void
rf_ReconMapUpdate(RF_Raid_t *raidPtr, RF_ReconMap_t *mapPtr,
    RF_SectorNum_t startSector, RF_SectorNum_t stopSector)
{
	RF_SectorCount_t sectorsPerReconUnit = mapPtr->sectorsPerReconUnit;
	RF_SectorNum_t i, first_in_RU, last_in_RU;
	RF_ReconMapListElem_t *p, *pt;

	RF_LOCK_MUTEX(mapPtr->mutex);
	RF_ASSERT(startSector >= 0 && stopSector < mapPtr->sectorsInDisk &&
	    stopSector >= startSector);

	while (startSector <= stopSector) {
		i = startSector / mapPtr->sectorsPerReconUnit;
		first_in_RU = i * sectorsPerReconUnit;
		last_in_RU = first_in_RU + sectorsPerReconUnit - 1;
		p = mapPtr->status[i];
		if (p != RU_ALL) {
			if (p == RU_NOTHING || p->startSector > startSector) {
				/* Insert at front of list. */

				mapPtr->status[i] =
				    rf_MakeReconMapListElem(startSector,
				     RF_MIN(stopSector, last_in_RU),
				     (p == RU_NOTHING) ? NULL : p);
				rf_update_size(mapPtr,
				    sizeof(RF_ReconMapListElem_t));

			} else {/* General case. */
				do {	/* Search for place to insert. */
					pt = p;
					p = p->next;
				} while (p && (p->startSector < startSector));
				pt->next = rf_MakeReconMapListElem(startSector,
				    RF_MIN(stopSector, last_in_RU), p);
				rf_update_size(mapPtr,
				    sizeof(RF_ReconMapListElem_t));
			}
			rf_compact_stat_entry(raidPtr, mapPtr, i);
		}
		startSector = RF_MIN(stopSector, last_in_RU) + 1;
	}
	RF_UNLOCK_MUTEX(mapPtr->mutex);
}


/*****************************************************************************
 *
 * Performs whatever list compactions can be done, and frees any space
 * that is no longer necessary. Assumes only that the list is sorted
 * by startSector. rf_crunch_list() compacts a single list as much as possible,
 * and the second block of code deletes the entire list if possible.
 * rf_crunch_list() is also called from MakeReconMapAccessList().
 *
 * When a recon unit is detected to be fully reconstructed, we set the
 * corresponding bit in the parity stripe map so that the head follow
 * code will not select this parity stripe again. This is redundant (but
 * harmless) when rf_compact_stat_entry is called from the reconstruction
 * code, but necessary when called from the user-write code.
 *
 *****************************************************************************/

void
rf_compact_stat_entry(RF_Raid_t *raidPtr, RF_ReconMap_t *mapPtr, int i)
{
	RF_SectorCount_t sectorsPerReconUnit = mapPtr->sectorsPerReconUnit;
	RF_ReconMapListElem_t *p = mapPtr->status[i];

	rf_crunch_list(mapPtr, p);

	if ((p->startSector == i * sectorsPerReconUnit) &&
	    (p->stopSector == i * sectorsPerReconUnit +
	     sectorsPerReconUnit - 1)) {
		mapPtr->status[i] = RU_ALL;
		mapPtr->unitsLeft--;
		rf_FreeReconMapListElem(mapPtr, p);
	}
}

void
rf_crunch_list(RF_ReconMap_t *mapPtr, RF_ReconMapListElem_t *listPtr)
{
	RF_ReconMapListElem_t *pt, *p = listPtr;

	if (!p)
		return;
	pt = p;
	p = p->next;
	while (p) {
		if (pt->stopSector >= p->startSector - 1) {
			pt->stopSector = RF_MAX(pt->stopSector, p->stopSector);
			pt->next = p->next;
			rf_FreeReconMapListElem(mapPtr, p);
			p = pt->next;
		} else {
			pt = p;
			p = p->next;
		}
	}
}


/*****************************************************************************
 *
 * Allocate and fill a new list element.
 *
 *****************************************************************************/

RF_ReconMapListElem_t *
rf_MakeReconMapListElem(RF_SectorNum_t startSector, RF_SectorNum_t stopSector,
    RF_ReconMapListElem_t *next)
{
	RF_ReconMapListElem_t *p;

	RF_Malloc(p, sizeof(RF_ReconMapListElem_t), (RF_ReconMapListElem_t *));
	if (p == NULL)
		return (NULL);
	p->startSector = startSector;
	p->stopSector = stopSector;
	p->next = next;
	return (p);
}


/*****************************************************************************
 *
 * Free a list element.
 *
 *****************************************************************************/

void
rf_FreeReconMapListElem(RF_ReconMap_t *mapPtr, RF_ReconMapListElem_t *p)
{
	int delta;

	if (mapPtr) {
		delta = 0 - (int) sizeof(RF_ReconMapListElem_t);
		rf_update_size(mapPtr, delta);
	}
	RF_Free(p, sizeof(*p));
}


/*****************************************************************************
 *
 * Free an entire status structure. Inefficient, but can be called at any
 * time.
 *
 *****************************************************************************/

void
rf_FreeReconMap(RF_ReconMap_t *mapPtr)
{
	RF_ReconMapListElem_t *p, *q;
	RF_ReconUnitCount_t numRUs;
	RF_ReconUnitNum_t i;

	numRUs = mapPtr->sectorsInDisk / mapPtr->sectorsPerReconUnit;
	if (mapPtr->sectorsInDisk % mapPtr->sectorsPerReconUnit)
		numRUs++;

	for (i = 0; i < numRUs; i++) {
		p = mapPtr->status[i];
		while (p != RU_NOTHING && p != RU_ALL) {
			q = p;
			p = p->next;
			RF_Free(q, sizeof(*q));
		}
	}
	rf_mutex_destroy(&mapPtr->mutex);
	RF_Free(mapPtr->status, mapPtr->totalRUs *
	    sizeof(RF_ReconMapListElem_t *));
	RF_Free(mapPtr, sizeof(RF_ReconMap_t));
}


/*****************************************************************************
 *
 * Returns nonzero if the indicated RU has been reconstructed already.
 *
 *****************************************************************************/

int
rf_CheckRUReconstructed(RF_ReconMap_t *mapPtr, RF_SectorNum_t startSector)
{
	RF_ReconMapListElem_t *l;	/* Used for searching. */
	RF_ReconUnitNum_t i;

	i = startSector / mapPtr->sectorsPerReconUnit;
	l = mapPtr->status[i];
	return ((l == RU_ALL) ? 1 : 0);
}

RF_ReconUnitCount_t
rf_UnitsLeftToReconstruct(RF_ReconMap_t *mapPtr)
{
	RF_ASSERT(mapPtr != NULL);
	return (mapPtr->unitsLeft);
}

/* Updates the size fields of a status descriptor. */
void
rf_update_size(RF_ReconMap_t *mapPtr, int size)
{
	mapPtr->size += size;
	mapPtr->maxSize = RF_MAX(mapPtr->size, mapPtr->maxSize);
}

void
rf_PrintList(RF_ReconMapListElem_t *listPtr)
{
	while (listPtr) {
		printf("%d,%d -> ", (int) listPtr->startSector,
		    (int) listPtr->stopSector);
		listPtr = listPtr->next;
	}
	printf("\n");
}

void
rf_PrintReconMap(RF_Raid_t *raidPtr, RF_ReconMap_t *mapPtr, RF_RowCol_t frow,
    RF_RowCol_t fcol)
{
	RF_ReconUnitCount_t numRUs;
	RF_ReconMapListElem_t *p;
	RF_ReconUnitNum_t i;

	numRUs = mapPtr->totalRUs;
	if (mapPtr->sectorsInDisk % mapPtr->sectorsPerReconUnit)
		numRUs++;

	for (i = 0; i < numRUs; i++) {
		p = mapPtr->status[i];
		if (p == RU_ALL)
			/* printf("[%d] ALL.\n", i) */;
		else
			if (p == RU_NOTHING) {
				printf("%d: Unreconstructed.\n", i);
			} else {
				printf("%d: ", i);
				rf_PrintList(p);
			}
	}
}

void
rf_PrintReconSchedule(RF_ReconMap_t *mapPtr, struct timeval *starttime)
{
	static int old_pctg = -1;
	struct timeval tv, diff;
	int new_pctg;

	new_pctg = 100 - (rf_UnitsLeftToReconstruct(mapPtr) * 100 /
	    mapPtr->totalRUs);
	if (new_pctg != old_pctg) {
		RF_GETTIME(tv);
		RF_TIMEVAL_DIFF(starttime, &tv, &diff);
		printf("%d %d.%06d\n", (int) new_pctg, (int) diff.tv_sec,
		    (int) diff.tv_usec);
		old_pctg = new_pctg;
	}
}