rf_parityscan.c

RAIDFrame是个非常好的磁盘阵列RAID仿真工具

     */
    return(RF_PARITY_OKAY);
  }
  rc = RF_PARITY_OKAY;
  if (lp->VerifyParity) {
    for(doasm=aasm;doasm;doasm=doasm->next) {
      for(parityPDA=doasm->parityInfo;parityPDA;parityPDA=parityPDA->next) {
        lrc = lp->VerifyParity(raidPtr, doasm->raidAddress, parityPDA,
          correct_it, flags);
        if (lrc > rc) {
          /* see rf_parityscan.h for why this works */
          rc = lrc;
        }
      }
    }
  }
  else {
    rc = RF_PARITY_COULD_NOT_VERIFY;
  }
  return(rc);
}

int rf_VerifyParityBasic(raidPtr, raidAddr, parityPDA, correct_it, flags)
  RF_Raid_t             *raidPtr;
  RF_RaidAddr_t          raidAddr;
  RF_PhysDiskAddr_t     *parityPDA;
  int                    correct_it;
  RF_RaidAccessFlags_t   flags;
{
  RF_RaidLayout_t *layoutPtr = &(raidPtr->Layout);
  RF_RaidAddr_t startAddr = rf_RaidAddressOfPrevStripeBoundary(layoutPtr, raidAddr);
  RF_SectorCount_t numsector = parityPDA->numSector;
  int numbytes  = rf_RaidAddressToByte(raidPtr, numsector);
  int bytesPerStripe = numbytes * layoutPtr->numDataCol;
  RF_DagHeader_t *rd_dag_h, *wr_dag_h;          /* read, write dag */
  RF_DagNode_t *blockNode, *unblockNode, *wrBlock, *wrUnblock;
  RF_AccessStripeMapHeader_t *asm_h;
  RF_AccessStripeMap_t *asmap;
  RF_AllocListElem_t *alloclist;
  RF_PhysDiskAddr_t *pda;
  char *pbuf, *buf, *end_p, *p;
  int i, retcode;
  RF_ReconUnitNum_t which_ru;
  RF_StripeNum_t psID = rf_RaidAddressToParityStripeID(layoutPtr, raidAddr, &which_ru);
  int stripeWidth = layoutPtr->numDataCol + layoutPtr->numParityCol;
  RF_AccTraceEntry_t tracerec;
  RF_MCPair_t *mcpair;

  retcode = RF_PARITY_OKAY;

  mcpair = rf_AllocMCPair();
  rf_MakeAllocList(alloclist);
  RF_MallocAndAdd(buf, numbytes * (layoutPtr->numDataCol + layoutPtr->numParityCol), (char *), alloclist);
  RF_CallocAndAdd(pbuf, 1, numbytes, (char *), alloclist);     /* use calloc to make sure buffer is zeroed */
  end_p = buf + bytesPerStripe;

  rd_dag_h = rf_MakeSimpleDAG(raidPtr, stripeWidth, numbytes, buf, rf_DiskReadFunc, rf_DiskReadUndoFunc,
			   "Rod", alloclist, flags, RF_IO_NORMAL_PRIORITY);
  blockNode = rd_dag_h->succedents[0];
  unblockNode = blockNode->succedents[0]->succedents[0];

  /* map the stripe and fill in the PDAs in the dag */
  asm_h = rf_MapAccess(raidPtr, startAddr, layoutPtr->dataSectorsPerStripe, buf, RF_DONT_REMAP);
  asmap = asm_h->stripeMap;
  
  for (pda=asmap->physInfo,i=0; i<layoutPtr->numDataCol; i++,pda=pda->next) {
    RF_ASSERT(pda);
    rf_RangeRestrictPDA(raidPtr, parityPDA, pda, 0, 1);
    RF_ASSERT(pda->numSector != 0);
    if (rf_TryToRedirectPDA(raidPtr, pda, 0)) goto out;   /* no way to verify parity if disk is dead.  return w/ good status */
    blockNode->succedents[i]->params[0].p = pda;
    blockNode->succedents[i]->params[2].v = psID;
    blockNode->succedents[i]->params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
  }

  RF_ASSERT(!asmap->parityInfo->next);
  rf_RangeRestrictPDA(raidPtr, parityPDA, asmap->parityInfo, 0, 1);
  RF_ASSERT(asmap->parityInfo->numSector != 0);
  if (rf_TryToRedirectPDA(raidPtr, asmap->parityInfo, 1))
    goto out;
  blockNode->succedents[layoutPtr->numDataCol]->params[0].p = asmap->parityInfo;

  /* fire off the DAG */
  bzero((char *)&tracerec,sizeof(tracerec));
  rd_dag_h->tracerec = &tracerec;

  if (rf_verifyParityDebug) {
    printf("Parity verify read dag:\n");
    rf_PrintDAGList(rd_dag_h);
  }

  RF_LOCK_MUTEX(mcpair->mutex);
  mcpair->flag = 0;
  rf_DispatchDAG(rd_dag_h, rf_MCPairWakeupFunc, (void *) mcpair);
  while (!mcpair->flag) RF_WAIT_COND(mcpair->cond, mcpair->mutex);
  RF_UNLOCK_MUTEX(mcpair->mutex);
  if (rd_dag_h->status != rf_enable) {
    RF_ERRORMSG("Unable to verify parity:  can't read the stripe\n");
    retcode = RF_PARITY_COULD_NOT_VERIFY;
    goto out;
  }

  for (p=buf; p<end_p; p+=numbytes) {
    rf_bxor(p, pbuf, numbytes, NULL);
  }
  for (i=0; i<numbytes; i++) if (pbuf[i] != buf[bytesPerStripe+i]) {
    if (!correct_it) RF_ERRORMSG3("Parity verify error: byte %d of parity is 0x%x should be 0x%x\n",
			       i,(u_char) buf[bytesPerStripe+i],(u_char) pbuf[i]);
    retcode = RF_PARITY_BAD;
    break;
  }

  if (retcode && correct_it) {
    wr_dag_h = rf_MakeSimpleDAG(raidPtr, 1, numbytes, pbuf, rf_DiskWriteFunc, rf_DiskWriteUndoFunc,
			     "Wnp", alloclist, flags, RF_IO_NORMAL_PRIORITY);
    wrBlock = wr_dag_h->succedents[0]; wrUnblock = wrBlock->succedents[0]->succedents[0];
    wrBlock->succedents[0]->params[0].p = asmap->parityInfo;
    wrBlock->succedents[0]->params[2].v = psID;
    wrBlock->succedents[0]->params[3].v = RF_CREATE_PARAM3(RF_IO_NORMAL_PRIORITY, 0, 0, which_ru);
    bzero((char *)&tracerec,sizeof(tracerec));
    wr_dag_h->tracerec = &tracerec;
    if (rf_verifyParityDebug) {
      printf("Parity verify write dag:\n");
      rf_PrintDAGList(wr_dag_h);
    }
    RF_LOCK_MUTEX(mcpair->mutex);
    mcpair->flag = 0;
    rf_DispatchDAG(wr_dag_h, rf_MCPairWakeupFunc, (void *) mcpair);
    while (!mcpair->flag)
      RF_WAIT_COND(mcpair->cond, mcpair->mutex);
    RF_UNLOCK_MUTEX(mcpair->mutex);
    if (wr_dag_h->status != rf_enable) {
      RF_ERRORMSG("Unable to correct parity in VerifyParity:  can't write the stripe\n");
      retcode = RF_PARITY_COULD_NOT_CORRECT;
    }
    rf_FreeDAG(wr_dag_h);
    if (retcode == RF_PARITY_BAD)
      retcode = RF_PARITY_CORRECTED;
  }

out:
  rf_FreeAccessStripeMap(asm_h);
  rf_FreeAllocList(alloclist);
  rf_FreeDAG(rd_dag_h);
  rf_FreeMCPair(mcpair);
  return(retcode);
}

int rf_TryToRedirectPDA(raidPtr, pda, parity)
  RF_Raid_t          *raidPtr;
  RF_PhysDiskAddr_t  *pda;
  int                 parity;
{
  if (raidPtr->Disks[pda->row][pda->col].status == rf_ds_reconstructing) {
    if (rf_CheckRUReconstructed(raidPtr->reconControl[pda->row]->reconMap, pda->startSector)) {
      if (raidPtr->Layout.map->flags & RF_DISTRIBUTE_SPARE) {
	RF_RowCol_t or = pda->row, oc = pda->col;
	RF_SectorNum_t os = pda->startSector;
	if (parity) {
	  (raidPtr->Layout.map->MapParity)(raidPtr, pda->raidAddress, &pda->row, &pda->col, &pda->startSector, RF_REMAP);
	  if (rf_verifyParityDebug) printf("VerifyParity: Redir P r %d c %d sect %ld -> r %d c %d sect %ld\n",
					or,oc,os,pda->row,pda->col,pda->startSector);
	} else {
	  (raidPtr->Layout.map->MapSector)(raidPtr, pda->raidAddress, &pda->row, &pda->col, &pda->startSector, RF_REMAP);
	  if (rf_verifyParityDebug) printf("VerifyParity: Redir D r %d c %d sect %ld -> r %d c %d sect %ld\n",
					or,oc,os,pda->row,pda->col,pda->startSector);
	}
      } else {
	RF_RowCol_t spRow = raidPtr->Disks[pda->row][pda->col].spareRow;
	RF_RowCol_t spCol = raidPtr->Disks[pda->row][pda->col].spareCol;
	pda->row = spRow;
	pda->col = spCol;
      }
    }
  }
  if (RF_DEAD_DISK(raidPtr->Disks[pda->row][pda->col].status)) return(1);
  return(0);
}

/*****************************************************************************************
 *
 * currently a stub.
 *
 * takes as input an ASM describing a write operation and containing one failure, and
 * verifies that the parity was correctly updated to reflect the write.
 *
 * if it's a data unit that's failed, we read the other data units in the stripe and
 * the parity unit, XOR them together, and verify that we get the data intended for
 * the failed disk.  Since it's easy, we also validate that the right data got written
 * to the surviving data disks.
 *
 * If it's the parity that failed, there's really no validation we can do except the
 * above verification that the right data got written to all disks.  This is because
 * the new data intended for the failed disk is supplied in the ASM, but this is of
 * course not the case for the new parity.
 *
 ****************************************************************************************/
int rf_VerifyDegrModeWrite(raidPtr, asmh)
  RF_Raid_t                   *raidPtr;
  RF_AccessStripeMapHeader_t  *asmh;
{
  return(0);
}

/* creates a simple DAG with a header, a block-recon node at level 1,
 * nNodes nodes at level 2, an unblock-recon node at level 3, and
 * a terminator node at level 4.  The stripe address field in
 * the block and unblock nodes are not touched, nor are the pda
 * fields in the second-level nodes, so they must be filled in later.
 *
 * commit point is established at unblock node - this means that any
 * failure during dag execution causes the dag to fail
 */
RF_DagHeader_t *rf_MakeSimpleDAG(raidPtr, nNodes, bytesPerSU, databuf, doFunc, undoFunc, name, alloclist, flags, priority)
  RF_Raid_t              *raidPtr;
  int                     nNodes;
  int                     bytesPerSU;
  char                   *databuf;
  int                   (*doFunc)();
  int                   (*undoFunc)();
  char                   *name;        /* node names at the second level */
  RF_AllocListElem_t     *alloclist;
  RF_RaidAccessFlags_t    flags;
  int                     priority;
{
  RF_DagHeader_t *dag_h;
  RF_DagNode_t *nodes, *termNode, *blockNode, *unblockNode;
  int i;
  
  /* create the nodes, the block & unblock nodes, and the terminator node */
  RF_CallocAndAdd(nodes, nNodes+3, sizeof(RF_DagNode_t), (RF_DagNode_t *), alloclist);
  blockNode   = &nodes[nNodes];
  unblockNode = blockNode+1;
  termNode   = unblockNode+1;

  dag_h = rf_AllocDAGHeader();
  dag_h->raidPtr = (void *) raidPtr;
  dag_h->allocList = NULL;                               /* we won't use this alloc list */
  dag_h->status = rf_enable;
  dag_h->numSuccedents = 1;
  dag_h->creator = "SimpleDAG";

  /* this dag can not commit until the unblock node is reached
   * errors prior to the commit point imply the dag has failed
   */
  dag_h->numCommitNodes = 1;
  dag_h->numCommits = 0;

  dag_h->succedents[0] = blockNode;
  rf_InitNode(blockNode,   rf_wait, RF_FALSE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, nNodes, 0, 0, 0, dag_h, "Nil", alloclist);
  rf_InitNode(unblockNode, rf_wait, RF_TRUE, rf_NullNodeFunc, rf_NullNodeUndoFunc, NULL, 1, nNodes, 0, 0, dag_h, "Nil", alloclist);
  unblockNode->succedents[0] = termNode;
  for (i=0; i<nNodes; i++) {
    blockNode->succedents[i] = unblockNode->antecedents[i] = &nodes[i];
    unblockNode->antType[i] = rf_control;
    rf_InitNode(&nodes[i], rf_wait, RF_FALSE, doFunc, undoFunc, rf_GenericWakeupFunc, 1, 1, 4, 0, dag_h, name, alloclist);
    nodes[i].succedents[0] =  unblockNode;
    nodes[i].antecedents[0] = blockNode;
    nodes[i].antType[0] = rf_control;
    nodes[i].params[1].p = (databuf + (i*bytesPerSU));
  }
  rf_InitNode(termNode, rf_wait, RF_FALSE, rf_TerminateFunc, rf_TerminateUndoFunc, NULL, 0, 1, 0, 0, dag_h, "Trm", alloclist);
  termNode->antecedents[0] = unblockNode;
  termNode->antType[0] = rf_control;
  return(dag_h);
}