/* $NetBSD: rf_reconmap.c,v 1.29.4.1 2007/03/24 14:55:46 yamt 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 __KERNEL_RCSID(0, "$NetBSD: rf_reconmap.c,v 1.29.4.1 2007/03/24 14:55:46 yamt Exp $"); #include "rf_raid.h" #include #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 memset 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) /* For most reconstructs we need at most 3 RF_ReconMapListElem_t's. * Bounding the number we need is quite difficult, as it depends on how * badly the sectors to be reconstructed get divided up. In the current * code, the reconstructed sectors appeared aligned on stripe boundaries, * and are always presented in stripe width units, so we're probably * allocating quite a bit more than we'll ever need. */ #define RF_NUM_RECON_POOL_ELEM 100 static void compact_stat_entry(RF_Raid_t * raidPtr, RF_ReconMap_t * mapPtr, int i); static void crunch_list(RF_ReconMap_t *mapPtr, RF_ReconMapListElem_t * listPtr); static RF_ReconMapListElem_t * MakeReconMapListElem(RF_ReconMap_t *mapPtr, RF_SectorNum_t startSector, RF_SectorNum_t stopSector, RF_ReconMapListElem_t * next); static void FreeReconMapListElem(RF_ReconMap_t *mapPtr, RF_ReconMapListElem_t * p); #if 0 static void PrintList(RF_ReconMapListElem_t * listPtr); #endif /*--------------------------------------------------------------------------- * * Creates and initializes new Reconstruction map * * ru_sectors - size of reconstruction unit in sectors * disk_sectors - size of disk in sectors * spareUnitsPerDisk - zero unless distributed sparing *-------------------------------------------------------------------------*/ RF_ReconMap_t * rf_MakeReconMap(RF_Raid_t *raidPtr, RF_SectorCount_t ru_sectors, RF_SectorCount_t disk_sectors, RF_ReconUnitCount_t spareUnitsPerDisk) { RF_RaidLayout_t *layoutPtr = &raidPtr->Layout; RF_ReconUnitCount_t num_rus = layoutPtr->stripeUnitsPerDisk / layoutPtr->SUsPerRU; RF_ReconMap_t *p; 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) memset((char *) p->status, 0, num_rus * sizeof(RF_ReconMapListElem_t *)); pool_init(&p->elem_pool, sizeof(RF_ReconMapListElem_t), 0, 0, 0, "raidreconpl", NULL, IPL_BIO); pool_prime(&p->elem_pool, RF_NUM_RECON_POOL_ELEM); rf_mutex_init(&p->mutex); 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 (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 compact_stat_entry() assumes is that the list * is sorted by startSector, and so this is the only condition I * maintain here. (MCH) * * This code now uses a pool instead of the previous malloc/free * stuff. *-------------------------------------------------------------------------*/ 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); while(mapPtr->lock) { ltsleep(&mapPtr->lock, PRIBIO, "reconupdate", 0, &mapPtr->mutex); } mapPtr->lock = 1; RF_UNLOCK_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] = MakeReconMapListElem(mapPtr,startSector, RF_MIN(stopSector, last_in_RU), (p == RU_NOTHING) ? NULL : p); } else {/* general case */ do { /* search for place to insert */ pt = p; p = p->next; } while (p && (p->startSector < startSector)); pt->next = MakeReconMapListElem(mapPtr,startSector, RF_MIN(stopSector, last_in_RU), p); } compact_stat_entry(raidPtr, mapPtr, i); } startSector = RF_MIN(stopSector, last_in_RU) + 1; } RF_LOCK_MUTEX(mapPtr->mutex); mapPtr->lock = 0; wakeup(&mapPtr->lock); 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. crunch_list() compacts a single list as much as * possible, and the second block of code deletes the entire list if * possible. 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 compact_stat_entry is called from the * reconstruction code, but necessary when called from the user-write * code. * *-------------------------------------------------------------------------*/ static void 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]; crunch_list(mapPtr, p); if ((p->startSector == i * sectorsPerReconUnit) && (p->stopSector == i * sectorsPerReconUnit + sectorsPerReconUnit - 1)) { mapPtr->status[i] = RU_ALL; mapPtr->unitsLeft--; FreeReconMapListElem(mapPtr, p); } } static void 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; FreeReconMapListElem(mapPtr, p); p = pt->next; } else { pt = p; p = p->next; } } } /*--------------------------------------------------------------------------- * * Allocate and fill a new list element * *-------------------------------------------------------------------------*/ static RF_ReconMapListElem_t * MakeReconMapListElem(RF_ReconMap_t *mapPtr, RF_SectorNum_t startSector, RF_SectorNum_t stopSector, RF_ReconMapListElem_t *next) { RF_ReconMapListElem_t *p; p = pool_get(&mapPtr->elem_pool, PR_WAITOK); p->startSector = startSector; p->stopSector = stopSector; p->next = next; return (p); } /*--------------------------------------------------------------------------- * * Free a list element * *-------------------------------------------------------------------------*/ static void FreeReconMapListElem(RF_ReconMap_t *mapPtr, RF_ReconMapListElem_t *p) { pool_put(&mapPtr->elem_pool, 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)); } } pool_destroy(&mapPtr->elem_pool); 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); } #if 0 static void 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 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); PrintList(p); } } } #endif #if RF_DEBUG_RECON 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; } } #endif