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core: Check transaction against execution cycles

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When we are validating a transaction, we take into account declared
ordering between job units. However, since JOB_STOP goes always first
regardless of the ordering constraint between respective units, we may
detect some false cycles in the transaction which would not prevent the
execution though.

Use the same logic in transaction checking as we use for job execution.
This commit is contained in:
Michal Koutný
2019-06-06 23:27:20 +02:00
committed by Michal Koutný
parent e602f15282
commit dfd79eca55
1 changed files with 29 additions and 16 deletions
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45
src/core/transaction.c
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@@ -353,6 +353,11 @@ static int transaction_verify_order_one(Transaction *tr, Job *j, Job *from, unsi
Unit *u;
void *v;
int r;
static const UnitDependency directions[] = {
UNIT_BEFORE,
UNIT_AFTER,
};
size_t d;
assert(tr);
assert(j);
@@ -441,25 +446,33 @@ static int transaction_verify_order_one(Transaction *tr, Job *j, Job *from, unsi
j->marker = from ? from : j;
j->generation = generation;
/* We assume that the dependencies are bidirectional, and
* hence can ignore UNIT_AFTER */
HASHMAP_FOREACH_KEY(v, u, j->unit->dependencies[UNIT_BEFORE], i) {
Job *o;
/* Actual ordering of jobs depends on the unit ordering dependency and job types. We need to traverse
* the graph over 'before' edges in the actual job execution order. We traverse over both unit
* ordering dependencies and we test with job_compare() whether it is the 'before' edge in the job
* execution ordering. */
for (d = 0; d < ELEMENTSOF(directions); d++) {
HASHMAP_FOREACH_KEY(v, u, j->unit->dependencies[directions[d]], i) {
Job *o;
/* Is there a job for this unit? */
o = hashmap_get(tr->jobs, u);
if (!o) {
/* Ok, there is no job for this in the
* transaction, but maybe there is already one
* running? */
o = u->job;
if (!o)
/* Is there a job for this unit? */
o = hashmap_get(tr->jobs, u);
if (!o) {
/* Ok, there is no job for this in the
* transaction, but maybe there is already one
* running? */
o = u->job;
if (!o)
continue;
}
/* Cut traversing if the job j is not really *before* o. */
if (job_compare(j, o, directions[d]) >= 0)
continue;
}
r = transaction_verify_order_one(tr, o, j, generation, e);
if (r < 0)
return r;
r = transaction_verify_order_one(tr, o, j, generation, e);
if (r < 0)
return r;
}
}
/* Ok, let's backtrack, and remember that this entry is not on