434 lines
16 KiB
C
434 lines
16 KiB
C
/* $NetBSD: rf_pqdegdags.c,v 1.8 2001/11/13 07:11:16 lukem Exp $ */
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/*
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* Copyright (c) 1995 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Author: Daniel Stodolsky
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/*
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* rf_pqdegdags.c
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* Degraded mode dags for double fault cases.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: rf_pqdegdags.c,v 1.8 2001/11/13 07:11:16 lukem Exp $");
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#include "rf_archs.h"
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#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)
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#include <dev/raidframe/raidframevar.h>
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#include "rf_raid.h"
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#include "rf_dag.h"
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#include "rf_dagdegrd.h"
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#include "rf_dagdegwr.h"
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#include "rf_dagfuncs.h"
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#include "rf_dagutils.h"
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#include "rf_etimer.h"
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#include "rf_acctrace.h"
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#include "rf_general.h"
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#include "rf_pqdegdags.h"
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#include "rf_pq.h"
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static void
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applyPDA(RF_Raid_t * raidPtr, RF_PhysDiskAddr_t * pda, RF_PhysDiskAddr_t * ppda,
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RF_PhysDiskAddr_t * qpda, void *bp);
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/*
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Two data drives have failed, and we are doing a read that covers one of them.
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We may also be reading some of the surviving drives.
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*****************************************************************************************
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*
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* creates a DAG to perform a degraded-mode read of data within one stripe.
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* This DAG is as follows:
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*
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* Hdr
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* |
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* Block
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* / / \ \ \ \
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* Rud ... Rud Rrd ... Rrd Rp Rq
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* | \ | \ | \ | \ | \ | \
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*
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* | |
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* Unblock X
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* \ /
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* ------ T ------
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*
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* Each R node is a successor of the L node
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* One successor arc from each R node goes to U, and the other to X
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* There is one Rud for each chunk of surviving user data requested by the user,
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* and one Rrd for each chunk of surviving user data _not_ being read by the user
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* R = read, ud = user data, rd = recovery (surviving) data, p = P data, q = Qdata
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* X = pq recovery node, T = terminate
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*
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* The block & unblock nodes are leftovers from a previous version. They
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* do nothing, but I haven't deleted them because it would be a tremendous
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* effort to put them back in.
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*
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* Note: The target buffer for the XOR node is set to the actual user buffer where the
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* failed data is supposed to end up. This buffer is zero'd by the code here. Thus,
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* if you create a degraded read dag, use it, and then re-use, you have to be sure to
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* zero the target buffer prior to the re-use.
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*
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* Every buffer read is passed to the pq recovery node, whose job it is to sort out whats
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* needs and what's not.
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****************************************************************************************/
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/* init a disk node with 2 successors and one predecessor */
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#define INIT_DISK_NODE(node,name) \
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rf_InitNode(node, rf_wait, RF_FALSE, rf_DiskReadFunc, rf_DiskReadUndoFunc, rf_GenericWakeupFunc, 2,1,4,0, dag_h, name, allocList); \
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(node)->succedents[0] = unblockNode; \
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(node)->succedents[1] = recoveryNode; \
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(node)->antecedents[0] = blockNode; \
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(node)->antType[0] = rf_control
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#define DISK_NODE_PARAMS(_node_,_p_) \
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(_node_).params[0].p = _p_ ; \
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(_node_).params[1].p = (_p_)->bufPtr; \
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(_node_).params[2].v = parityStripeID; \
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(_node_).params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru)
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#define DISK_NODE_PDA(node) ((node)->params[0].p)
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_DoubleDegRead)
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{
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rf_DoubleDegRead(raidPtr, asmap, dag_h, bp, flags, allocList,
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"Rq", "PQ Recovery", rf_PQDoubleRecoveryFunc);
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}
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static void
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applyPDA(raidPtr, pda, ppda, qpda, bp)
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RF_Raid_t *raidPtr;
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RF_PhysDiskAddr_t *pda;
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RF_PhysDiskAddr_t *ppda;
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RF_PhysDiskAddr_t *qpda;
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void *bp;
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{
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RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
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RF_RaidAddr_t s0off = rf_StripeUnitOffset(layoutPtr, ppda->startSector);
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RF_SectorCount_t s0len = ppda->numSector, len;
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RF_SectorNum_t suoffset;
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unsigned coeff;
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char *pbuf = ppda->bufPtr;
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char *qbuf = qpda->bufPtr;
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char *buf;
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int delta;
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suoffset = rf_StripeUnitOffset(layoutPtr, pda->startSector);
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len = pda->numSector;
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/* see if pda intersects a recovery pda */
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if ((suoffset < s0off + s0len) && (suoffset + len > s0off)) {
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buf = pda->bufPtr;
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coeff = rf_RaidAddressToStripeUnitID(&(raidPtr->Layout), pda->raidAddress);
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coeff = (coeff % raidPtr->Layout.numDataCol);
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if (suoffset < s0off) {
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delta = s0off - suoffset;
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buf += rf_RaidAddressToStripeUnitID(&(raidPtr->Layout), delta);
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suoffset = s0off;
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len -= delta;
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}
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if (suoffset > s0off) {
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delta = suoffset - s0off;
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pbuf += rf_RaidAddressToStripeUnitID(&(raidPtr->Layout), delta);
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qbuf += rf_RaidAddressToStripeUnitID(&(raidPtr->Layout), delta);
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}
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if ((suoffset + len) > (s0len + s0off))
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len = s0len + s0off - suoffset;
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/* src, dest, len */
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rf_bxor(buf, pbuf, rf_RaidAddressToByte(raidPtr, len), bp);
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/* dest, src, len, coeff */
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rf_IncQ((unsigned long *) qbuf, (unsigned long *) buf, rf_RaidAddressToByte(raidPtr, len), coeff);
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}
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}
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/*
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Recover data in the case of a double failure. There can be two
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result buffers, one for each chunk of data trying to be recovered.
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The params are pda's that have not been range restricted or otherwise
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politely massaged - this should be done here. The last params are the
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pdas of P and Q, followed by the raidPtr. The list can look like
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pda, pda, ... , p pda, q pda, raidptr, asm
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or
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pda, pda, ... , p_1 pda, p_2 pda, q_1 pda, q_2 pda, raidptr, asm
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depending on wether two chunks of recovery data were required.
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The second condition only arises if there are two failed buffers
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whose lengths do not add up a stripe unit.
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*/
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int
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rf_PQDoubleRecoveryFunc(node)
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RF_DagNode_t *node;
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{
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int np = node->numParams;
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RF_AccessStripeMap_t *asmap = (RF_AccessStripeMap_t *) node->params[np - 1].p;
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RF_Raid_t *raidPtr = (RF_Raid_t *) node->params[np - 2].p;
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RF_RaidLayout_t *layoutPtr = (RF_RaidLayout_t *) & (raidPtr->Layout);
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int d, i;
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unsigned coeff;
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RF_RaidAddr_t sosAddr, suoffset;
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RF_SectorCount_t len, secPerSU = layoutPtr->sectorsPerStripeUnit;
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int two = 0;
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RF_PhysDiskAddr_t *ppda, *ppda2, *qpda, *qpda2, *pda, npda;
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char *buf;
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int numDataCol = layoutPtr->numDataCol;
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RF_Etimer_t timer;
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RF_AccTraceEntry_t *tracerec = node->dagHdr->tracerec;
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RF_ETIMER_START(timer);
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if (asmap->failedPDAs[1] &&
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(asmap->failedPDAs[1]->numSector + asmap->failedPDAs[0]->numSector < secPerSU)) {
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RF_ASSERT(0);
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ppda = node->params[np - 6].p;
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ppda2 = node->params[np - 5].p;
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qpda = node->params[np - 4].p;
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qpda2 = node->params[np - 3].p;
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d = (np - 6);
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two = 1;
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} else {
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ppda = node->params[np - 4].p;
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qpda = node->params[np - 3].p;
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d = (np - 4);
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}
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for (i = 0; i < d; i++) {
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pda = node->params[i].p;
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buf = pda->bufPtr;
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suoffset = rf_StripeUnitOffset(layoutPtr, pda->startSector);
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len = pda->numSector;
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coeff = rf_RaidAddressToStripeUnitID(layoutPtr, pda->raidAddress);
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/* compute the data unit offset within the column */
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coeff = (coeff % raidPtr->Layout.numDataCol);
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/* see if pda intersects a recovery pda */
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applyPDA(raidPtr, pda, ppda, qpda, node->dagHdr->bp);
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if (two)
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applyPDA(raidPtr, pda, ppda, qpda, node->dagHdr->bp);
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}
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/* ok, we got the parity back to the point where we can recover. We
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* now need to determine the coeff of the columns that need to be
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* recovered. We can also only need to recover a single stripe unit. */
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if (asmap->failedPDAs[1] == NULL) { /* only a single stripe unit
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* to recover. */
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pda = asmap->failedPDAs[0];
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sosAddr = rf_RaidAddressOfPrevStripeBoundary(layoutPtr, asmap->raidAddress);
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/* need to determine the column of the other failed disk */
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coeff = rf_RaidAddressToStripeUnitID(layoutPtr, pda->raidAddress);
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/* compute the data unit offset within the column */
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coeff = (coeff % raidPtr->Layout.numDataCol);
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for (i = 0; i < numDataCol; i++) {
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npda.raidAddress = sosAddr + (i * secPerSU);
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(raidPtr->Layout.map->MapSector) (raidPtr, npda.raidAddress, &(npda.row), &(npda.col), &(npda.startSector), 0);
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/* skip over dead disks */
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if (RF_DEAD_DISK(raidPtr->Disks[npda.row][npda.col].status))
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if (i != coeff)
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break;
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}
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RF_ASSERT(i < numDataCol);
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RF_ASSERT(two == 0);
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/* recover the data. Since we need only want to recover one
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* column, we overwrite the parity with the other one. */
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if (coeff < i) /* recovering 'a' */
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rf_PQ_recover((unsigned long *) ppda->bufPtr, (unsigned long *) qpda->bufPtr, (unsigned long *) pda->bufPtr, (unsigned long *) ppda->bufPtr, rf_RaidAddressToByte(raidPtr, pda->numSector), coeff, i);
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else /* recovering 'b' */
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rf_PQ_recover((unsigned long *) ppda->bufPtr, (unsigned long *) qpda->bufPtr, (unsigned long *) ppda->bufPtr, (unsigned long *) pda->bufPtr, rf_RaidAddressToByte(raidPtr, pda->numSector), i, coeff);
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} else
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RF_PANIC();
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RF_ETIMER_STOP(timer);
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RF_ETIMER_EVAL(timer);
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if (tracerec)
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tracerec->q_us += RF_ETIMER_VAL_US(timer);
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rf_GenericWakeupFunc(node, 0);
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return (0);
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}
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int
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rf_PQWriteDoubleRecoveryFunc(node)
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RF_DagNode_t *node;
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{
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/* The situation:
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*
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* We are doing a write that hits only one failed data unit. The other
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* failed data unit is not being overwritten, so we need to generate
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* it.
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*
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* For the moment, we assume all the nonfailed data being written is in
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* the shadow of the failed data unit. (i.e,, either a single data
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* unit write or the entire failed stripe unit is being overwritten. )
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*
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* Recovery strategy: apply the recovery data to the parity and q. Use P
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* & Q to recover the second failed data unit in P. Zero fill Q, then
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* apply the recovered data to p. Then apply the data being written to
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* the failed drive. Then walk through the surviving drives, applying
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* new data when it exists, othewise the recovery data. Quite a mess.
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*
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*
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* The params
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*
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* read pda0, read pda1, ... read pda (numDataCol-3), write pda0, ... ,
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* write pda (numStripeUnitAccess - numDataFailed), failed pda,
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* raidPtr, asmap */
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int np = node->numParams;
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RF_AccessStripeMap_t *asmap = (RF_AccessStripeMap_t *) node->params[np - 1].p;
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RF_Raid_t *raidPtr = (RF_Raid_t *) node->params[np - 2].p;
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RF_RaidLayout_t *layoutPtr = (RF_RaidLayout_t *) & (raidPtr->Layout);
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int i;
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RF_RaidAddr_t sosAddr;
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unsigned coeff;
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RF_StripeCount_t secPerSU = layoutPtr->sectorsPerStripeUnit;
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RF_PhysDiskAddr_t *ppda, *qpda, *pda, npda;
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int numDataCol = layoutPtr->numDataCol;
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RF_Etimer_t timer;
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RF_AccTraceEntry_t *tracerec = node->dagHdr->tracerec;
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RF_ASSERT(node->numResults == 2);
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RF_ASSERT(asmap->failedPDAs[1] == NULL);
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RF_ETIMER_START(timer);
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ppda = node->results[0];
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qpda = node->results[1];
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/* apply the recovery data */
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for (i = 0; i < numDataCol - 2; i++)
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applyPDA(raidPtr, node->params[i].p, ppda, qpda, node->dagHdr->bp);
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/* determine the other failed data unit */
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pda = asmap->failedPDAs[0];
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sosAddr = rf_RaidAddressOfPrevStripeBoundary(layoutPtr, asmap->raidAddress);
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/* need to determine the column of the other failed disk */
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coeff = rf_RaidAddressToStripeUnitID(layoutPtr, pda->raidAddress);
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/* compute the data unit offset within the column */
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coeff = (coeff % raidPtr->Layout.numDataCol);
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for (i = 0; i < numDataCol; i++) {
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npda.raidAddress = sosAddr + (i * secPerSU);
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(raidPtr->Layout.map->MapSector) (raidPtr, npda.raidAddress, &(npda.row), &(npda.col), &(npda.startSector), 0);
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/* skip over dead disks */
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if (RF_DEAD_DISK(raidPtr->Disks[npda.row][npda.col].status))
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if (i != coeff)
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break;
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}
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RF_ASSERT(i < numDataCol);
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/* recover the data. The column we want to recover we write over the
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* parity. The column we don't care about we dump in q. */
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if (coeff < i) /* recovering 'a' */
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rf_PQ_recover((unsigned long *) ppda->bufPtr, (unsigned long *) qpda->bufPtr, (unsigned long *) ppda->bufPtr, (unsigned long *) qpda->bufPtr, rf_RaidAddressToByte(raidPtr, pda->numSector), coeff, i);
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else /* recovering 'b' */
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rf_PQ_recover((unsigned long *) ppda->bufPtr, (unsigned long *) qpda->bufPtr, (unsigned long *) qpda->bufPtr, (unsigned long *) ppda->bufPtr, rf_RaidAddressToByte(raidPtr, pda->numSector), i, coeff);
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/* OK. The valid data is in P. Zero fill Q, then inc it into it. */
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memset(qpda->bufPtr, 0, rf_RaidAddressToByte(raidPtr, qpda->numSector));
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rf_IncQ((unsigned long *) qpda->bufPtr, (unsigned long *) ppda->bufPtr, rf_RaidAddressToByte(raidPtr, qpda->numSector), i);
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/* now apply all the write data to the buffer */
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/* single stripe unit write case: the failed data is only thing we are
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* writing. */
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RF_ASSERT(asmap->numStripeUnitsAccessed == 1);
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/* dest, src, len, coeff */
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rf_IncQ((unsigned long *) qpda->bufPtr, (unsigned long *) asmap->failedPDAs[0]->bufPtr, rf_RaidAddressToByte(raidPtr, qpda->numSector), coeff);
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rf_bxor(asmap->failedPDAs[0]->bufPtr, ppda->bufPtr, rf_RaidAddressToByte(raidPtr, ppda->numSector), node->dagHdr->bp);
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/* now apply all the recovery data */
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for (i = 0; i < numDataCol - 2; i++)
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applyPDA(raidPtr, node->params[i].p, ppda, qpda, node->dagHdr->bp);
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RF_ETIMER_STOP(timer);
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RF_ETIMER_EVAL(timer);
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if (tracerec)
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tracerec->q_us += RF_ETIMER_VAL_US(timer);
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rf_GenericWakeupFunc(node, 0);
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return (0);
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}
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_DDLargeWrite)
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{
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RF_PANIC();
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}
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/*
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Two lost data unit write case.
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There are really two cases here:
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(1) The write completely covers the two lost data units.
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In that case, a reconstruct write that doesn't write the
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failed data units will do the correct thing. So in this case,
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the dag looks like
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full stripe read of surviving data units (not being overwriten)
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write new data (ignoring failed units) compute P&Q
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write P&Q
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(2) The write does not completely cover both failed data units
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(but touches at least one of them). Then we need to do the
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equivalent of a reconstruct read to recover the missing data
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unit from the other stripe.
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For any data we are writing that is not in the "shadow"
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of the failed units, we need to do a four cycle update.
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PANIC on this case. for now
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*/
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RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateWriteDAG)
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{
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RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
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RF_SectorCount_t sectorsPerSU = layoutPtr->sectorsPerStripeUnit;
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int sum;
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int nf = asmap->numDataFailed;
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sum = asmap->failedPDAs[0]->numSector;
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if (nf == 2)
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sum += asmap->failedPDAs[1]->numSector;
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if ((nf == 2) && (sum == (2 * sectorsPerSU))) {
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/* large write case */
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rf_PQ_DDLargeWrite(raidPtr, asmap, dag_h, bp, flags, allocList);
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return;
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}
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if ((nf == asmap->numStripeUnitsAccessed) || (sum >= sectorsPerSU)) {
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/* small write case, no user data not in shadow */
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|
rf_PQ_DDSimpleSmallWrite(raidPtr, asmap, dag_h, bp, flags, allocList);
|
|
return;
|
|
}
|
|
RF_PANIC();
|
|
}
|
|
RF_CREATE_DAG_FUNC_DECL(rf_PQ_DDSimpleSmallWrite)
|
|
{
|
|
rf_DoubleDegSmallWrite(raidPtr, asmap, dag_h, bp, flags, allocList, "Rq", "Wq", "PQ Recovery", rf_PQWriteDoubleRecoveryFunc);
|
|
}
|
|
#endif /* (RF_INCLUDE_DECL_PQ > 0) ||
|
|
* (RF_INCLUDE_RAID6 > 0) */
|