/*
* 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 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)
{
#if RF_ACC_TRACE > 0
RF_AccTraceEntry_t *tracerec = &desc->tracerec;
RF_Etimer_t timer;
#endif
RF_DagHeader_t *dag_h;
RF_DagList_t *dagList;
struct buf *bp;
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. */
#if RF_ACC_TRACE > 0
RF_ETIMER_START(timer);
#endif
/* SelectAlgorithm returns one or more dags */
selectStatus = rf_SelectAlgorithm(desc, desc->flags | RF_DAG_SUPPRESS_LOCKS);
#if RF_DEBUG_VALIDATE_DAG
if (rf_printDAGsDebug) {
dagList = desc->dagList;
for (i = 0; i < desc->numStripes; i++) {
rf_PrintDAGList(dagList->dags);
dagList = dagList->next;
}
}
#endif /* RF_DEBUG_VALIDATE_DAG */
#if RF_ACC_TRACE > 0
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);
#endif
desc->status = 0; /* good status */
if (selectStatus || (desc->numRetries > RF_RETRY_THRESHOLD)) {
/* failed to create a dag */
/* this happens when there are too many faults or incomplete
* dag libraries */
if (selectStatus) {
printf("raid%d: failed to create a dag. "
"Too many component failures.\n",
desc->raidPtr->raidid);
} else {
printf("raid%d: IO failed after %d retries.\n",
desc->raidPtr->raidid, RF_RETRY_THRESHOLD);
}
desc->status = 1; /* bad status */
/* skip straight to rf_State_Cleanup() */
desc->state = rf_CleanupState;
bp = (struct buf *)desc->bp;
bp->b_error = EIO;
bp->b_resid = bp->b_bcount;
} else {
/* bind dags to desc */
dagList = desc->dagList;
for (i = 0; i < desc->numStripes; i++) {
dag_h = dagList->dags;
while (dag_h) {
dag_h->bp = (struct buf *) desc->bp;
#if RF_ACC_TRACE > 0
dag_h->tracerec = tracerec;
#endif
dag_h = dag_h->next;
}
dagList = dagList->next;
}
desc->flags |= RF_DAG_DISPATCH_RETURNED;
desc->state++; /* next state should be rf_State_ExecuteDAG */
}
return RF_FALSE;
}
