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rf_raid5_rotatedspare.c revision 1.4 
      1 /*	$NetBSD: rf_raid5_rotatedspare.c,v 1.4 2000/01/07 03:41:03 oster Exp $	*/
      2 /*
      3  * Copyright (c) 1995 Carnegie-Mellon University.
      4  * All rights reserved.
      5  *
      6  * Author: Khalil Amiri
      7  *
      8  * Permission to use, copy, modify and distribute this software and
      9  * its documentation is hereby granted, provided that both the copyright
     10  * notice and this permission notice appear in all copies of the
     11  * software, derivative works or modified versions, and any portions
     12  * thereof, and that both notices appear in supporting documentation.
     13  *
     14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     16  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     17  *
     18  * Carnegie Mellon requests users of this software to return to
     19  *
     20  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     21  *  School of Computer Science
     22  *  Carnegie Mellon University
     23  *  Pittsburgh PA 15213-3890
     24  *
     25  * any improvements or extensions that they make and grant Carnegie the
     26  * rights to redistribute these changes.
     27  */
     28 
     29 /**************************************************************************
     30  *
     31  * rf_raid5_rotated_spare.c -- implements RAID Level 5 with rotated sparing
     32  *
     33  **************************************************************************/
     34 
     35 #include "rf_raid.h"
     36 #include "rf_raid5.h"
     37 #include "rf_dag.h"
     38 #include "rf_dagutils.h"
     39 #include "rf_dagfuncs.h"
     40 #include "rf_general.h"
     41 #include "rf_utils.h"
     42 #include "rf_raid5_rotatedspare.h"
     43 
     44 typedef struct RF_Raid5RSConfigInfo_s {
     45 	RF_RowCol_t **stripeIdentifier;	/* filled in at config time & used by
     46 					 * IdentifyStripe */
     47 }       RF_Raid5RSConfigInfo_t;
     48 
     49 int
     50 rf_ConfigureRAID5_RS(
     51     RF_ShutdownList_t ** listp,
     52     RF_Raid_t * raidPtr,
     53     RF_Config_t * cfgPtr)
     54 {
     55 	RF_RaidLayout_t *layoutPtr = &raidPtr->Layout;
     56 	RF_Raid5RSConfigInfo_t *info;
     57 	RF_RowCol_t i, j, startdisk;
     58 
     59 	/* create a RAID level 5 configuration structure */
     60 	RF_MallocAndAdd(info, sizeof(RF_Raid5RSConfigInfo_t), (RF_Raid5RSConfigInfo_t *), raidPtr->cleanupList);
     61 	if (info == NULL)
     62 		return (ENOMEM);
     63 	layoutPtr->layoutSpecificInfo = (void *) info;
     64 
     65 	RF_ASSERT(raidPtr->numRow == 1);
     66 	RF_ASSERT(raidPtr->numCol >= 3);
     67 
     68 	/* the stripe identifier must identify the disks in each stripe, IN
     69 	 * THE ORDER THAT THEY APPEAR IN THE STRIPE. */
     70 	info->stripeIdentifier = rf_make_2d_array(raidPtr->numCol, raidPtr->numCol, raidPtr->cleanupList);
     71 	if (info->stripeIdentifier == NULL)
     72 		return (ENOMEM);
     73 	startdisk = 0;
     74 	for (i = 0; i < raidPtr->numCol; i++) {
     75 		for (j = 0; j < raidPtr->numCol; j++) {
     76 			info->stripeIdentifier[i][j] = (startdisk + j) % raidPtr->numCol;
     77 		}
     78 		if ((--startdisk) < 0)
     79 			startdisk = raidPtr->numCol - 1;
     80 	}
     81 
     82 	/* fill in the remaining layout parameters */
     83 	layoutPtr->numStripe = layoutPtr->stripeUnitsPerDisk;
     84 	layoutPtr->bytesPerStripeUnit = layoutPtr->sectorsPerStripeUnit << raidPtr->logBytesPerSector;
     85 	layoutPtr->numDataCol = raidPtr->numCol - 2;
     86 	layoutPtr->dataSectorsPerStripe = layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
     87 	layoutPtr->numParityCol = 1;
     88 	layoutPtr->dataStripeUnitsPerDisk = layoutPtr->stripeUnitsPerDisk;
     89 	raidPtr->sectorsPerDisk = layoutPtr->stripeUnitsPerDisk * layoutPtr->sectorsPerStripeUnit;
     90 
     91 	raidPtr->totalSectors = layoutPtr->stripeUnitsPerDisk * layoutPtr->numDataCol * layoutPtr->sectorsPerStripeUnit;
     92 
     93 	return (0);
     94 }
     95 
     96 RF_ReconUnitCount_t
     97 rf_GetNumSpareRUsRAID5_RS(raidPtr)
     98 	RF_Raid_t *raidPtr;
     99 {
    100 	return (raidPtr->Layout.stripeUnitsPerDisk / raidPtr->numCol);
    101 }
    102 
    103 void
    104 rf_MapSectorRAID5_RS(
    105     RF_Raid_t * raidPtr,
    106     RF_RaidAddr_t raidSector,
    107     RF_RowCol_t * row,
    108     RF_RowCol_t * col,
    109     RF_SectorNum_t * diskSector,
    110     int remap)
    111 {
    112 	RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
    113 
    114 	*row = 0;
    115 	if (remap) {
    116 		*col = raidPtr->numCol - 1 - (1 + SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
    117 		*col = (*col + 1) % raidPtr->numCol;	/* spare unit is rotated
    118 							 * with parity; line
    119 							 * above maps to parity */
    120 	} else {
    121 		*col = (SUID + (SUID / raidPtr->Layout.numDataCol)) % raidPtr->numCol;
    122 	}
    123 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
    124 	    (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    125 }
    126 
    127 void
    128 rf_MapParityRAID5_RS(
    129     RF_Raid_t * raidPtr,
    130     RF_RaidAddr_t raidSector,
    131     RF_RowCol_t * row,
    132     RF_RowCol_t * col,
    133     RF_SectorNum_t * diskSector,
    134     int remap)
    135 {
    136 	RF_StripeNum_t SUID = raidSector / raidPtr->Layout.sectorsPerStripeUnit;
    137 
    138 	*row = 0;
    139 	*col = raidPtr->numCol - 1 - (1 + SUID / raidPtr->Layout.numDataCol) % raidPtr->numCol;
    140 	*diskSector = (SUID / (raidPtr->Layout.numDataCol)) * raidPtr->Layout.sectorsPerStripeUnit +
    141 	    (raidSector % raidPtr->Layout.sectorsPerStripeUnit);
    142 	if (remap)
    143 		*col = (*col + 1) % raidPtr->numCol;
    144 }
    145 
    146 void
    147 rf_IdentifyStripeRAID5_RS(
    148     RF_Raid_t * raidPtr,
    149     RF_RaidAddr_t addr,
    150     RF_RowCol_t ** diskids,
    151     RF_RowCol_t * outRow)
    152 {
    153 	RF_StripeNum_t stripeID = rf_RaidAddressToStripeID(&raidPtr->Layout, addr);
    154 	RF_Raid5RSConfigInfo_t *info = (RF_Raid5RSConfigInfo_t *) raidPtr->Layout.layoutSpecificInfo;
    155 	*outRow = 0;
    156 	*diskids = info->stripeIdentifier[stripeID % raidPtr->numCol];
    157 
    158 }
    159 
    160 void
    161 rf_MapSIDToPSIDRAID5_RS(
    162     RF_RaidLayout_t * layoutPtr,
    163     RF_StripeNum_t stripeID,
    164     RF_StripeNum_t * psID,
    165     RF_ReconUnitNum_t * which_ru)
    166 {
    167 	*which_ru = 0;
    168 	*psID = stripeID;
    169 }
    170