rf_pqdeg.c

RAIDFrame是个非常好的磁盘阵列RAID仿真工具

/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Daniel Stodolsky
 *
 * 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  [e-mail]
 *  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.
 */

/*
 * $Log: rf_pqdeg.c,v $
 * Revision 1.18  1996/07/31  16:30:01  jimz
 * asm/asmap fix
 *
 * Revision 1.17  1996/07/31  15:35:09  jimz
 * evenodd changes; bugfixes for double-degraded archs, generalize
 * some formerly PQ-only functions
 *
 * Revision 1.16  1996/07/27  23:36:08  jimz
 * Solaris port of simulator
 *
 * Revision 1.15  1996/07/22  19:52:16  jimz
 * switched node params to RF_DagParam_t, a union of
 * a 64-bit int and a void *, for better portability
 * attempted hpux port, but failed partway through for
 * lack of a single C compiler capable of compiling all
 * source files
 *
 * Revision 1.14  1996/06/02  17:31:48  jimz
 * Moved a lot of global stuff into array structure, where it belongs.
 * Fixed up paritylogging, pss modules in this manner. Some general
 * code cleanup. Removed lots of dead code, some dead files.
 *
 * Revision 1.13  1996/05/31  22:26:54  jimz
 * fix a lot of mapping problems, memory allocation problems
 * found some weird lock issues, fixed 'em
 * more code cleanup
 *
 * Revision 1.12  1996/05/27  18:56:37  jimz
 * more code cleanup
 * better typing
 * compiles in all 3 environments
 *
 * Revision 1.11  1996/05/24  22:17:04  jimz
 * continue code + namespace cleanup
 * typed a bunch of flags
 *
 * Revision 1.10  1996/05/24  04:28:55  jimz
 * release cleanup ckpt
 *
 * Revision 1.9  1996/05/18  19:51:34  jimz
 * major code cleanup- fix syntax, make some types consistent,
 * add prototypes, clean out dead code, et cetera
 *
 * Revision 1.8  1996/05/03  19:41:07  wvcii
 * added includes for dag library
 *
 * Revision 1.7  1995/11/30  16:19:36  wvcii
 * added copyright info
 *
 * Revision 1.6  1995/11/07  16:15:08  wvcii
 * updated/added prototyping for dag creation
 *
 * Revision 1.5  1995/03/01  20:25:48  holland
 * kernelization changes
 *
 * Revision 1.4  1995/02/03  22:31:36  holland
 * many changes related to kernelization
 *
 * Revision 1.3  1995/02/01  15:13:05  holland
 * moved #include of general.h out of raid.h and into each file
 *
 * Revision 1.2  1994/12/05  04:50:26  danner
 * additional pq support
 *
 * Revision 1.1  1994/11/29  20:36:02  danner
 * Initial revision
 *
 */

#include "rf_archs.h"

#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)

#include "rf_types.h"
#include "rf_raid.h"
#include "rf_dag.h"
#include "rf_dagutils.h"
#include "rf_dagfuncs.h"
#include "rf_dagffrd.h"
#include "rf_dagffwr.h"
#include "rf_dagdegrd.h"
#include "rf_dagdegwr.h"
#include "rf_threadid.h"
#include "rf_etimer.h"
#include "rf_pqdeg.h"
#include "rf_general.h"
#include "rf_pqdegdags.h"
#include "rf_pq.h"

/*
   Degraded mode dag functions for P+Q calculations.

   The following nomenclature is used. 

   PQ_<D><P><Q>_Create{Large,Small}<Write|Read>DAG

   where <D><P><Q> are single digits representing the number of failed
   data units <D> (0,1,2), parity units <P> (0,1), and Q units <Q>, effecting
   the I/O. The reads have only  PQ_<D><P><Q>_CreateReadDAG variants, while
   the single fault writes have both large and small write versions. (Single fault
   PQ is equivalent to normal mode raid 5 in many aspects. 

   Some versions degenerate into the same case, and are grouped together below.
*/

/* Reads, single failure 

   we have parity, so we can do a raid 5
   reconstruct read.
*/

RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateReadDAG)
{
  rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
}

/* Reads double failure  */

/*
   Q is lost, but not parity
   so we can a raid 5 reconstruct read.
*/

RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateReadDAG)
{
  rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
}

/*
  parity is lost, so we need to
  do a reconstruct read and recompute
  the data with Q.
*/

RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateReadDAG)
{
  RF_PhysDiskAddr_t *temp;
  /* swap P and Q pointers to fake out the DegradedReadDAG code */
  temp = asmap->parityInfo; asmap->parityInfo = asmap->qInfo; asmap->qInfo = temp;
  rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_qRecoveryFuncs);
}

/*
  Two data units are dead in this stripe, so we will need read
  both P and Q to reconstruct the data. Note that only 
  one data unit we are reading may actually be missing. 
*/
RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG)
{
  rf_PQ_DoubleDegRead(raidPtr, asmap, dag_h, bp, flags, allocList);
}

RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG)
{
  rf_CreateDoubleDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList);
}

/* Writes, single failure */

RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG)
{
  if (asmap->numStripeUnitsAccessed != 1 && 
      asmap->failedPDA->numSector != raidPtr->Layout.sectorsPerStripeUnit) 
    RF_PANIC();
  rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
    allocList, 2, (int (*)())rf_Degraded_100_PQFunc, RF_FALSE);
}

/* Dead  P - act like a RAID 5 small write with parity = Q */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateSmallWriteDAG)
{
  RF_PhysDiskAddr_t *temp;
  /* swap P and Q pointers to fake out the DegradedReadDAG code */
  temp = asmap->parityInfo; asmap->parityInfo = asmap->qInfo; asmap->qInfo = temp;
  rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_qFuncs, NULL);
}

/* Dead Q - act like a RAID 5 small write */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateSmallWriteDAG)
{
  rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pFuncs, NULL);
}

/* Dead P - act like a RAID 5 large write but for Q */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateLargeWriteDAG)
{
  RF_PhysDiskAddr_t *temp;
  /* swap P and Q pointers to fake out the code */
  temp = asmap->parityInfo; asmap->parityInfo = asmap->qInfo; asmap->qInfo = temp;
  rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularQFunc, RF_FALSE);
}

/* Dead Q - act like a RAID 5 large write */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateLargeWriteDAG)
{
  rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList, 1, rf_RegularPFunc, RF_FALSE);
}


/*
 * writes, double failure
 */

/*
 * Lost P & Q - do a nonredundant write 
 */
RF_CREATE_DAG_FUNC_DECL(rf_PQ_011_CreateWriteDAG)
{
  rf_CreateNonRedundantWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
    RF_IO_TYPE_WRITE);
}

/*
   In the two cases below,
   A nasty case arises when the write a (strict) portion of a failed stripe unit
   and parts of another su. For now, we do not support this.
*/

/*
  Lost Data and  P - do a Q write.
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateWriteDAG)
{
  RF_PhysDiskAddr_t *temp;

  if (asmap->numStripeUnitsAccessed != 1 && 
      asmap->failedPDA->numSector != raidPtr->Layout.sectorsPerStripeUnit)
  {
    RF_PANIC();
  }
  /* swap P and Q to fake out parity code */
  temp = asmap->parityInfo;
  asmap->parityInfo = asmap->qInfo;
  asmap->qInfo = temp;
  rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
    allocList,1, (int (*)())rf_PQ_DegradedWriteQFunc, RF_FALSE); 
  /* is the regular Q func the right one to call? */
}

/*
   Lost Data and Q - do degraded mode P write
*/
RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateWriteDAG)
{
  if (asmap->numStripeUnitsAccessed != 1 && 
      asmap->failedPDA->numSector != raidPtr->Layout.sectorsPerStripeUnit)
    RF_PANIC();
  rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
    allocList,1, rf_RecoveryXorFunc, RF_FALSE);
}

#endif /* (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0) */