NetBSD/sys/dev/raidframe/rf_states.c

/*	$NetBSD: rf_states.c,v 1.5 1999/01/26 04:40:03 oster Exp $	*/
/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Mark Holland, William V. Courtright II, Robby Findler
 *
 * 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.
 */

#include <sys/errno.h>

#include "rf_archs.h"
#include "rf_threadstuff.h"
#include "rf_raid.h"
#include "rf_dag.h"
#include "rf_desc.h"
#include "rf_aselect.h"
#include "rf_threadid.h"
#include "rf_general.h"
#include "rf_states.h"
#include "rf_dagutils.h"
#include "rf_driver.h"
#include "rf_engine.h"
#include "rf_map.h"
#include "rf_etimer.h"

#if defined(KERNEL) && (DKUSAGE > 0)
#include <sys/dkusage.h>
#include <io/common/iotypes.h>
#include <io/cam/dec_cam.h>
#include <io/cam/cam.h>
#include <io/cam/pdrv.h>
#endif /* KERNEL && DKUSAGE > 0 */

/* prototypes for some of the available states.

   States must:

     - not block.

     - either schedule rf_ContinueRaidAccess as a callback and return
       RF_TRUE, or complete all of their work and return RF_FALSE.

     - increment desc->state when they have finished their work.
*/

static char *StateName(RF_AccessState_t state)
{
  switch (state) {
    case rf_QuiesceState:            return "QuiesceState";
    case rf_MapState:                return "MapState";
    case rf_LockState:               return "LockState";
    case rf_CreateDAGState:          return "CreateDAGState";
    case rf_ExecuteDAGState:         return "ExecuteDAGState";
    case rf_ProcessDAGState:         return "ProcessDAGState";
    case rf_CleanupState:            return "CleanupState";
    case rf_LastState:               return "LastState";
    case rf_IncrAccessesCountState:  return "IncrAccessesCountState";
    case rf_DecrAccessesCountState:  return "DecrAccessesCountState";
    default:                         return "!!! UnnamedState !!!";
  }
}

void rf_ContinueRaidAccess(RF_RaidAccessDesc_t *desc)
{
  int suspended = RF_FALSE;
  int current_state_index = desc->state;
  RF_AccessState_t current_state = desc->states[current_state_index];
  
  do {

    current_state_index = desc->state;
    current_state = desc->states [current_state_index];

    switch (current_state) {

    case rf_QuiesceState: 		 suspended = rf_State_Quiesce(desc); 
				 break;
    case rf_IncrAccessesCountState: suspended = rf_State_IncrAccessCount(desc); 
				 break;
    case rf_MapState:		 suspended = rf_State_Map(desc); 
				 break;
    case rf_LockState:		 suspended = rf_State_Lock(desc);
				 break;
    case rf_CreateDAGState:	 suspended = rf_State_CreateDAG(desc); 
				 break;
    case rf_ExecuteDAGState:	 suspended = rf_State_ExecuteDAG(desc); 
				 break;
    case rf_ProcessDAGState:	 suspended = rf_State_ProcessDAG(desc);
				 break;
    case rf_CleanupState: 	 suspended = rf_State_Cleanup(desc);
				 break;
    case rf_DecrAccessesCountState: suspended = rf_State_DecrAccessCount(desc);
				 break;
    case rf_LastState:		 suspended = rf_State_LastState(desc);
				 break;
    }

    /* after this point, we cannot dereference desc since desc may
       have been freed. desc is only freed in LastState, so if we
       renter this function or loop back up, desc should be valid. */

    if (rf_printStatesDebug) {
      int tid;
      rf_get_threadid (tid);

      printf ("[%d] State: %-24s StateIndex: %3i desc: 0x%ld %s\n",
	      tid, StateName(current_state), current_state_index, (long)desc, 
	      suspended ? "callback scheduled" : "looping");
    }
  } while (!suspended && current_state != rf_LastState);

  return;
}


void rf_ContinueDagAccess (RF_DagList_t *dagList)
{
  RF_AccTraceEntry_t *tracerec = &(dagList->desc->tracerec);
  RF_RaidAccessDesc_t *desc;
  RF_DagHeader_t *dag_h;
  RF_Etimer_t timer;
  int i;

  desc = dagList->desc;

  timer = tracerec->timer;
  RF_ETIMER_STOP(timer);
  RF_ETIMER_EVAL(timer);
  tracerec->specific.user.exec_us = RF_ETIMER_VAL_US(timer);
  RF_ETIMER_START(tracerec->timer);

  /* skip to dag which just finished */
  dag_h = dagList->dags;
  for (i = 0; i < dagList->numDagsDone; i++) {
    dag_h = dag_h->next;
  }

  /* check to see if retry is required */
  if (dag_h->status == rf_rollBackward) {
    /* when a dag fails, mark desc status as bad and allow all other dags
     * in the desc to execute to completion.  then, free all dags and start over */
    desc->status = 1;  /* bad status */
    {
      printf("[%d] DAG failure: %c addr 0x%lx (%ld) nblk 0x%x (%d) buf 0x%lx\n",
	     desc->tid, desc->type, (long)desc->raidAddress, 
	     (long)desc->raidAddress,(int)desc->numBlocks,
	     (int)desc->numBlocks, (unsigned long) (desc->bufPtr));
    }
  }

  dagList->numDagsDone++;
  rf_ContinueRaidAccess(desc);
}


int rf_State_LastState(RF_RaidAccessDesc_t *desc)
{
  void (*callbackFunc)(RF_CBParam_t) = desc->callbackFunc;
  RF_CBParam_t callbackArg;

  callbackArg.p = desc->callbackArg;

  if (!(desc->flags & RF_DAG_TEST_ACCESS)) {/* don't biodone if this */
#if DKUSAGE > 0
    RF_DKU_END_IO(((RF_Raid_t *)desc->raidPtr)->raidid,(struct buf *)desc->bp);
#else
    RF_DKU_END_IO(((RF_Raid_t *)desc->raidPtr)->raidid);
#endif /* DKUSAGE > 0 */

    /*
     * If this is not an async request, wake up the caller
     */
    if (desc->async_flag == 0)
    	wakeup(desc->bp);

    /*     printf("Calling biodone on 0x%x\n",desc->bp); */
    biodone(desc->bp); 			/* access came through ioctl */
  }

  if (callbackFunc) callbackFunc(callbackArg);
  rf_FreeRaidAccDesc(desc);

  return RF_FALSE;
}

int rf_State_IncrAccessCount(RF_RaidAccessDesc_t *desc)
{
  RF_Raid_t *raidPtr;

  raidPtr = desc->raidPtr;
  /* Bummer. We have to do this to be 100% safe w.r.t. the increment below */
  RF_LOCK_MUTEX(raidPtr->access_suspend_mutex);
  raidPtr->accs_in_flight++; /* used to detect quiescence */
  RF_UNLOCK_MUTEX(raidPtr->access_suspend_mutex);

  desc->state++;
  return RF_FALSE;
}

int rf_State_DecrAccessCount(RF_RaidAccessDesc_t *desc)
{
  RF_Raid_t *raidPtr;

  raidPtr = desc->raidPtr;

  RF_LOCK_MUTEX(raidPtr->access_suspend_mutex);
  raidPtr->accs_in_flight--;
  if (raidPtr->accesses_suspended && raidPtr->accs_in_flight == 0)  {
    rf_SignalQuiescenceLock(raidPtr, raidPtr->reconDesc);
  }
  rf_UpdateUserStats(raidPtr, RF_ETIMER_VAL_US(desc->timer), desc->numBlocks);
  RF_UNLOCK_MUTEX(raidPtr->access_suspend_mutex);

  desc->state++;
  return RF_FALSE;
}

int rf_State_Quiesce(RF_RaidAccessDesc_t *desc)
{
  RF_AccTraceEntry_t *tracerec     = &desc->tracerec;
  RF_Etimer_t timer;
  int suspended = RF_FALSE;
  RF_Raid_t *raidPtr;

  raidPtr = desc->raidPtr;

  RF_ETIMER_START(timer);
  RF_ETIMER_START(desc->timer);

  RF_LOCK_MUTEX(raidPtr->access_suspend_mutex);
  if (raidPtr->accesses_suspended) {
    RF_CallbackDesc_t *cb;
    cb = rf_AllocCallbackDesc();
    /* XXX the following cast is quite bogus...  rf_ContinueRaidAccess
       takes a (RF_RaidAccessDesc_t *) as an argument..  GO */
    cb->callbackFunc = (void (*)(RF_CBParam_t))rf_ContinueRaidAccess;
    cb->callbackArg.p  = (void *) desc;
    cb->next = raidPtr->quiesce_wait_list;
    raidPtr->quiesce_wait_list = cb;
    suspended = RF_TRUE;
  } 

  RF_UNLOCK_MUTEX(raidPtr->access_suspend_mutex);
  
  RF_ETIMER_STOP(timer); 
  RF_ETIMER_EVAL(timer);
  tracerec->specific.user.suspend_ovhd_us += RF_ETIMER_VAL_US(timer);
  
  if (suspended && rf_quiesceDebug) 
    printf("Stalling access due to quiescence lock\n");

  desc->state++;
  return suspended;
}

int rf_State_Map(RF_RaidAccessDesc_t *desc)
{
  RF_Raid_t *raidPtr               = desc->raidPtr;
  RF_AccTraceEntry_t *tracerec     = &desc->tracerec;
  RF_Etimer_t timer;

  RF_ETIMER_START(timer);

  if (!(desc->asmap = rf_MapAccess(raidPtr, desc->raidAddress, desc->numBlocks, 
			      desc->bufPtr, RF_DONT_REMAP)))
    RF_PANIC();
  
  RF_ETIMER_STOP(timer); 
  RF_ETIMER_EVAL(timer); 
  tracerec->specific.user.map_us = RF_ETIMER_VAL_US(timer);

  desc->state ++;
  return RF_FALSE;
}

int rf_State_Lock(RF_RaidAccessDesc_t *desc)
{
  RF_AccTraceEntry_t *tracerec     = &desc->tracerec;
  RF_Raid_t *raidPtr               = desc->raidPtr;
  RF_AccessStripeMapHeader_t *asmh = desc->asmap;
  RF_AccessStripeMap_t *asm_p;
  RF_Etimer_t timer;
  int suspended = RF_FALSE;

  RF_ETIMER_START(timer);
  if (!(raidPtr->Layout.map->flags & RF_NO_STRIPE_LOCKS)) {
    RF_StripeNum_t lastStripeID = -1;

    /* acquire each lock that we don't already hold */
    for (asm_p = asmh->stripeMap; asm_p; asm_p = asm_p->next) {
      RF_ASSERT(RF_IO_IS_R_OR_W(desc->type));
      if (!rf_suppressLocksAndLargeWrites && 
          asm_p->parityInfo && 
          !(desc->flags& RF_DAG_SUPPRESS_LOCKS) && 
          !(asm_p->flags & RF_ASM_FLAGS_LOCK_TRIED))
      {
        asm_p->flags |= RF_ASM_FLAGS_LOCK_TRIED;
        RF_ASSERT(asm_p->stripeID > lastStripeID); /* locks must be acquired
						   hierarchically */
        lastStripeID = asm_p->stripeID;
	/* XXX the cast to (void (*)(RF_CBParam_t)) below is bogus!  GO */
        RF_INIT_LOCK_REQ_DESC(asm_p->lockReqDesc, desc->type, 
            (void (*)(struct buf *))rf_ContinueRaidAccess, desc, asm_p, 
            raidPtr->Layout.dataSectorsPerStripe);
        if (rf_AcquireStripeLock(raidPtr->lockTable, asm_p->stripeID,
            &asm_p->lockReqDesc))
        {
          suspended = RF_TRUE;
          break;
        }
      }

      if (desc->type == RF_IO_TYPE_WRITE && 
          raidPtr->status[asm_p->physInfo->row] == rf_rs_reconstructing)
      {
        if (! (asm_p->flags & RF_ASM_FLAGS_FORCE_TRIED) ) {
          int val;

          asm_p->flags |= RF_ASM_FLAGS_FORCE_TRIED;
	  /* XXX the cast below is quite bogus!!! XXX  GO */
          val = rf_ForceOrBlockRecon(raidPtr, asm_p, 
		 (void (*)(RF_Raid_t *,void *))rf_ContinueRaidAccess, desc);
          if (val == 0) {
            asm_p->flags |= RF_ASM_FLAGS_RECON_BLOCKED;
          }
          else {
            suspended = RF_TRUE;
            break;
          }
        }
        else {
          if (rf_pssDebug) {
            printf("[%d] skipping force/block because already done, psid %ld\n",
                desc->tid,(long)asm_p->stripeID);
          }
        }
      }
      else {
        if (rf_pssDebug) {
          printf("[%d] skipping force/block because not write or not under recon, psid %ld\n",
              desc->tid,(long)asm_p->stripeID);
        }
      }
    }

    RF_ETIMER_STOP(timer); 
    RF_ETIMER_EVAL(timer); 
    tracerec->specific.user.lock_us += RF_ETIMER_VAL_US(timer);

    if (suspended)
      return(RF_TRUE);
  }

  desc->state++;
  return(RF_FALSE);
}

/*
 * the following three states create, execute, and post-process dags
 * the error recovery unit is a single dag.
 * by default, SelectAlgorithm creates an array of dags, one per parity stripe
 * in some tricky cases, multiple dags per stripe are created
 *   - dags within a parity stripe are executed sequentially (arbitrary order)
 *   - dags for distinct parity stripes are executed concurrently
 *
 * repeat until all dags complete successfully -or- dag selection fails
 *
 * while !done
 *   create dag(s) (SelectAlgorithm)
 *   if dag
 *     execute dag (DispatchDAG)
 *     if dag successful
 *       done (SUCCESS)
 *     else
 *       !done (RETRY - start over with new dags)
 *   else
 *     done (FAIL)
 */
int rf_State_CreateDAG (RF_RaidAccessDesc_t *desc)
{
  RF_AccTraceEntry_t *tracerec     = &desc->tracerec;
  RF_Etimer_t timer;
  RF_DagHeader_t *dag_h;
  int i, selectStatus;

  /* generate a dag for the access, and fire it off.  When the dag
     completes, we'll get re-invoked in the next state. */
  RF_ETIMER_START(timer);
  /* SelectAlgorithm returns one or more dags */
  selectStatus = rf_SelectAlgorithm(desc, desc->flags|RF_DAG_SUPPRESS_LOCKS);
  if (rf_printDAGsDebug)
    for (i = 0; i < desc->numStripes; i++)
      rf_PrintDAGList(desc->dagArray[i].dags);
  RF_ETIMER_STOP(timer); 
  RF_ETIMER_EVAL(timer); 
  /* update time to create all dags */
  tracerec->specific.user.dag_create_us = RF_ETIMER_VAL_US(timer);

  desc->status = 0; /* good status */

  if (selectStatus) {
    /* failed to create a dag */
    /* this happens when there are too many faults or incomplete dag libraries */
    printf("[Failed to create a DAG\n]");
    RF_PANIC();
  }
  else {
    /* bind dags to desc */
    for (i = 0; i < desc->numStripes; i++) {
      dag_h = desc->dagArray[i].dags;
      while (dag_h) {
	dag_h->bp = (struct buf *) desc->bp;
	dag_h->tracerec = tracerec;
	dag_h = dag_h->next;
      }
    }
    desc->flags |= RF_DAG_DISPATCH_RETURNED;
    desc->state++;  /* next state should be rf_State_ExecuteDAG */
  }
  return RF_FALSE;
}



/* the access has an array of dagLists, one dagList per parity stripe.
 * fire the first dag in each parity stripe (dagList).
 * dags within a stripe (dagList) must be executed sequentially
 *  - this preserves atomic parity update
 * dags for independents parity groups (stripes) are fired concurrently */

int rf_State_ExecuteDAG(RF_RaidAccessDesc_t *desc)
{
  int i;
  RF_DagHeader_t *dag_h;
  RF_DagList_t *dagArray = desc->dagArray;

  /* next state is always rf_State_ProcessDAG
   * important to do this before firing the first dag
   * (it may finish before we leave this routine) */
  desc->state++;

  /* sweep dag array, a stripe at a time, firing the first dag in each stripe */
  for (i = 0; i < desc->numStripes; i++) {
    RF_ASSERT(dagArray[i].numDags > 0);
    RF_ASSERT(dagArray[i].numDagsDone == 0);
    RF_ASSERT(dagArray[i].numDagsFired == 0);
    RF_ETIMER_START(dagArray[i].tracerec.timer);
    /* fire first dag in this stripe */
    dag_h = dagArray[i].dags;
    RF_ASSERT(dag_h);
    dagArray[i].numDagsFired++;
    /* XXX Yet another case where we pass in a conflicting function pointer
       :-(  XXX  GO */
    rf_DispatchDAG(dag_h, (void (*)(void *))rf_ContinueDagAccess, &dagArray[i]);
  }

  /* the DAG will always call the callback, even if there was no
   * blocking, so we are always suspended in this state */
  return RF_TRUE;
}



/* rf_State_ProcessDAG is entered when a dag completes.
 * first, check to all dags in the access have completed
 * if not, fire as many dags as possible */

int rf_State_ProcessDAG(RF_RaidAccessDesc_t *desc)
{
  RF_AccessStripeMapHeader_t *asmh = desc->asmap;
  RF_Raid_t *raidPtr               = desc->raidPtr;
  RF_DagHeader_t *dag_h;
  int i, j, done = RF_TRUE;
  RF_DagList_t *dagArray = desc->dagArray;
  RF_Etimer_t timer;

  /* check to see if this is the last dag */
  for (i = 0; i < desc->numStripes; i++)
    if (dagArray[i].numDags != dagArray[i].numDagsDone)
      done = RF_FALSE;

  if (done) {
    if (desc->status) {
      /* a dag failed, retry */
      RF_ETIMER_START(timer);
      /* free all dags */
      for (i = 0; i < desc->numStripes; i++) {
	rf_FreeDAG(desc->dagArray[i].dags);
      }
      rf_MarkFailuresInASMList(raidPtr, asmh);
      /* back up to rf_State_CreateDAG */
      desc->state = desc->state - 2;
      return RF_FALSE;
    }
    else {
      /* move on to rf_State_Cleanup */
      desc->state++;
    }
    return RF_FALSE;
  }
  else {
    /* more dags to execute */
    /* see if any are ready to be fired.  if so, fire them */
    /* don't fire the initial dag in a list, it's fired in rf_State_ExecuteDAG */
    for (i = 0; i < desc->numStripes; i++) {
      if ((dagArray[i].numDagsDone < dagArray[i].numDags)
	  && (dagArray[i].numDagsDone == dagArray[i].numDagsFired)
	  && (dagArray[i].numDagsFired > 0)) {
	RF_ETIMER_START(dagArray[i].tracerec.timer);
	/* fire next dag in this stripe */
	/* first, skip to next dag awaiting execution */
	dag_h = dagArray[i].dags;
	for (j = 0; j < dagArray[i].numDagsDone; j++)
	  dag_h = dag_h->next;
	dagArray[i].numDagsFired++;
	/* XXX and again we pass a different function pointer.. GO */
	rf_DispatchDAG(dag_h, (void (*)(void *))rf_ContinueDagAccess, 
		       &dagArray[i]);
      }
    }
    return RF_TRUE;
  }
}

/* only make it this far if all dags complete successfully */
int rf_State_Cleanup(RF_RaidAccessDesc_t *desc)
{
  RF_AccTraceEntry_t *tracerec     = &desc->tracerec;
  RF_AccessStripeMapHeader_t *asmh = desc->asmap;  
  RF_Raid_t *raidPtr               = desc->raidPtr;
  RF_AccessStripeMap_t *asm_p;
  RF_DagHeader_t *dag_h;
  RF_Etimer_t timer;
  int tid, i;

  desc->state ++;

  rf_get_threadid(tid);

  timer = tracerec->timer;
  RF_ETIMER_STOP(timer);
  RF_ETIMER_EVAL(timer); 
  tracerec->specific.user.dag_retry_us = RF_ETIMER_VAL_US(timer);
    
  /* the RAID I/O is complete.  Clean up. */
  tracerec->specific.user.dag_retry_us = 0;
  
  RF_ETIMER_START(timer);
  if (desc->flags & RF_DAG_RETURN_DAG) {
    /* copy dags into paramDAG */
    *(desc->paramDAG) = desc->dagArray[0].dags;
    dag_h = *(desc->paramDAG);
    for (i = 1; i < desc->numStripes; i++) {
      /* concatenate dags from remaining stripes */
      RF_ASSERT(dag_h);
      while (dag_h->next)
	dag_h = dag_h->next;
      dag_h->next = desc->dagArray[i].dags;
    }
  }
  else {
    /* free all dags */
    for (i = 0; i < desc->numStripes; i++) {
      rf_FreeDAG(desc->dagArray[i].dags);
    }
  }
  
  RF_ETIMER_STOP(timer); 
  RF_ETIMER_EVAL(timer); 
  tracerec->specific.user.cleanup_us = RF_ETIMER_VAL_US(timer);

  RF_ETIMER_START(timer);
  if (!(raidPtr->Layout.map->flags & RF_NO_STRIPE_LOCKS)) {
    for (asm_p = asmh->stripeMap; asm_p; asm_p = asm_p->next) {
      if (!rf_suppressLocksAndLargeWrites &&
          asm_p->parityInfo && 
          !(desc->flags&RF_DAG_SUPPRESS_LOCKS))
      {
        RF_ASSERT_VALID_LOCKREQ(&asm_p->lockReqDesc);
        rf_ReleaseStripeLock(raidPtr->lockTable, asm_p->stripeID, 
            &asm_p->lockReqDesc);
      }
      if (asm_p->flags & RF_ASM_FLAGS_RECON_BLOCKED) {
        rf_UnblockRecon(raidPtr, asm_p);
      }
    }
  }
  
  RF_ETIMER_STOP(timer); 
  RF_ETIMER_EVAL(timer); 
  tracerec->specific.user.lock_us += RF_ETIMER_VAL_US(timer);
  
  RF_ETIMER_START(timer);
  if (desc->flags & RF_DAG_RETURN_ASM) 
    *(desc->paramASM) = asmh;     
  else
    rf_FreeAccessStripeMap(asmh);
  RF_ETIMER_STOP(timer); 
  RF_ETIMER_EVAL(timer); 
  tracerec->specific.user.cleanup_us += RF_ETIMER_VAL_US(timer);
  
  RF_ETIMER_STOP(desc->timer); 
  RF_ETIMER_EVAL(desc->timer);

  timer = desc->tracerec.tot_timer;
  RF_ETIMER_STOP(timer);
  RF_ETIMER_EVAL(timer);
  desc->tracerec.total_us = RF_ETIMER_VAL_US(timer);

  rf_LogTraceRec(raidPtr, tracerec);

  desc->flags |= RF_DAG_ACCESS_COMPLETE;

  return RF_FALSE;
}