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make sure impact of transactions is minimized

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This commit is contained in:
Lennart Poettering 2010-01-21 02:59:12 +01:00
parent 1ffba6fe82
commit e094e853a0
6 changed files with 173 additions and 17 deletions
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9
job.c
View File

@ -264,3 +264,12 @@ bool job_type_is_superset(JobType a, JobType b) {
}
}
bool job_type_is_conflicting(JobType a, JobType b) {
/* Checks whether two types are "conflicting" */
return
(a == JOB_STOP && b != JOB_STOP) ||
(b == JOB_STOP && a != JOB_STOP);
}

1
job.h
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@ -94,5 +94,6 @@ const char* job_type_to_string(JobType t);
int job_type_merge(JobType *a, JobType b);
bool job_type_mergeable(JobType a, JobType b);
bool job_type_is_superset(JobType a, JobType b);
bool job_type_is_conflicting(JobType a, JobType b);
#endif

75
manager.c
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@ -244,9 +244,14 @@ static int transaction_merge_jobs(Manager *m) {
JobType t = j->type;
Job *k;
/* Merge all transactions */
for (k = j->transaction_next; k; k = k->transaction_next)
assert_se(job_type_merge(&t, k->type) == 0);
/* If an active job is mergable, merge it too */
if (j->name->meta.job)
job_type_merge(&t, j->name->meta.job->type); /* Might fail. Which is OK */
while ((k = j->transaction_next)) {
if (j->linked) {
transaction_merge_and_delete_job(m, k, j, t);
@ -399,15 +404,61 @@ static int transaction_is_destructive(Manager *m, JobMode mode) {
/* Checks whether applying this transaction means that
* existing jobs would be replaced */
HASHMAP_FOREACH(j, m->transaction_jobs, state)
HASHMAP_FOREACH(j, m->transaction_jobs, state) {
/* Assume merged */
assert(!j->transaction_prev);
assert(!j->transaction_next);
if (j->name->meta.job &&
j->name->meta.job != j &&
!job_type_is_superset(j->type, j->name->meta.job->type))
return -EEXIST;
}
return 0;
}
static void transaction_minimize_impact(Manager *m) {
bool again;
assert(m);
/* Drops all unnecessary jobs that reverse already active jobs
* or that stop a running service. */
do {
Job *j;
void *state;
again = false;
HASHMAP_FOREACH(j, m->transaction_jobs, state) {
for (; j; j = j->transaction_next) {
/* If it matters, we shouldn't drop it */
if (j->matters_to_anchor)
continue;
/* Would this stop a running service?
* Would this change an existing job?
* If so, let's drop this entry */
if ((j->type != JOB_STOP || name_is_dead(j->name)) &&
(!j->name->meta.job || job_type_is_conflicting(j->type, j->name->meta.job->state)))
continue;
/* Ok, let's get rid of this */
transaction_delete_job(m, j);
again = true;
break;
}
if (again)
break;
}
} while (again);
}
static int transaction_apply(Manager *m, JobMode mode) {
void *state;
Job *j;
@ -416,6 +467,10 @@ static int transaction_apply(Manager *m, JobMode mode) {
/* Moves the transaction jobs to the set of active jobs */
HASHMAP_FOREACH(j, m->transaction_jobs, state) {
/* Assume merged */
assert(!j->transaction_prev);
assert(!j->transaction_next);
if (j->linked)
continue;
@ -461,7 +516,6 @@ rollback:
return r;
}
static int transaction_activate(Manager *m, JobMode mode) {
int r;
unsigned generation = 1;
@ -474,12 +528,17 @@ static int transaction_activate(Manager *m, JobMode mode) {
/* First step: figure out which jobs matter */
transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
/* Second step: Try not to stop any running services if
* we don't have to. Don't try to reverse running
* jobs if we don't have to. */
transaction_minimize_impact(m);
for (;;) {
/* Second step: Let's remove unneeded jobs that might
/* Third step: Let's remove unneeded jobs that might
* be lurking. */
transaction_collect_garbage(m);
/* Third step: verify order makes sense and correct
/* Fourth step: verify order makes sense and correct
* cycles if necessary and possible */
if ((r = transaction_verify_order(m, &generation)) >= 0)
break;
@ -492,7 +551,7 @@ static int transaction_activate(Manager *m, JobMode mode) {
}
for (;;) {
/* Fourth step: let's drop unmergable entries if
/* Fifth step: let's drop unmergable entries if
* necessary and possible, merge entries we can
* merge */
if ((r = transaction_merge_jobs(m)) >= 0)
@ -501,7 +560,7 @@ static int transaction_activate(Manager *m, JobMode mode) {
if (r != -EAGAIN)
goto rollback;
/* Fifth step: an entry got dropped, let's garbage
/* Sixth step: an entry got dropped, let's garbage
* collect its dependencies. */
transaction_collect_garbage(m);
@ -509,12 +568,12 @@ static int transaction_activate(Manager *m, JobMode mode) {
* unmergable entries ... */
}
/* Sith step: check whether we can actually apply this */
/* Seventh step: check whether we can actually apply this */
if (mode == JOB_FAIL)
if ((r = transaction_is_destructive(m, mode)) < 0)
goto rollback;
/* Seventh step: apply changes */
/* Eights step: apply changes */
if ((r = transaction_apply(m, mode)) < 0)
goto rollback;

64
name.c
View File

@ -226,7 +226,6 @@ void name_free(Name *name) {
}
bool name_is_ready(Name *name) {
assert(name);
if (name->meta.state != NAME_LOADED)
@ -291,6 +290,69 @@ bool name_is_ready(Name *name) {
return false;
}
bool name_is_dead(Name *name) {
assert(name);
if (name->meta.state != NAME_LOADED)
return true;
assert(name->meta.type < _NAME_TYPE_MAX);
switch (name->meta.type) {
case NAME_SERVICE: {
Service *s = SERVICE(name);
return
s->state == SERVICE_DEAD ||
s->state == SERVICE_MAINTAINANCE;
}
case NAME_TIMER:
return TIMER(name)->state == TIMER_DEAD;
case NAME_SOCKET: {
Socket *s = SOCKET(name);
return
s->state == SOCKET_DEAD ||
s->state == SOCKET_MAINTAINANCE;
}
case NAME_MILESTONE:
return MILESTONE(name)->state == MILESTONE_DEAD;
case NAME_DEVICE:
return DEVICE(name)->state == DEVICE_DEAD;
case NAME_MOUNT: {
Mount *a = MOUNT(name);
return
a->state == AUTOMOUNT_DEAD ||
a->state == AUTOMOUNT_MAINTAINANCE;
}
case NAME_AUTOMOUNT: {
Automount *a = AUTOMOUNT(name);
return
a->state == AUTOMOUNT_DEAD ||
a->state == AUTOMOUNT_MAINTAINANCE;
}
case NAME_SNAPSHOT:
return SNAPSHOT(name)->state == SNAPSHOT_DEAD;
case _NAME_TYPE_MAX:
case _NAME_TYPE_INVALID:
;
}
assert_not_reached("Unknown name type.");
return false;
}
static int ensure_in_set(Set **s, void *data) {
int r;

14
name.h
View File

@ -124,8 +124,7 @@ typedef enum TimerState {
TIMER_RUNNING,
TIMER_STOP_PRE,
TIMER_STOP,
TIMER_STOP_POST,
TIMER_MAINTAINANCE
TIMER_STOP_POST
} TimerState;
struct Timer {
@ -193,7 +192,12 @@ struct Device {
typedef enum MountState {
MOUNT_DEAD,
MOUNT_BEFORE,
MOUNT_MOUNTED
MOUNT_MOUNTING,
MOUNT_MOUNTED,
MOUNT_UNMOUNTING,
MOUNT_SIGTERM, /* if the mount command hangs */
MOUNT_SIGKILL,
MOUNT_MAINTAINANCE
} MountState;
struct Mount {
@ -272,7 +276,9 @@ DEFINE_CAST(SNAPSHOT, Snapshot, snapshot);
/* For casting the various name types into a name */
#define NAME(o) ((Name*) (o))
bool name_is_ready(Name *name);
bool name_is_running(Name *name);
bool name_is_dead(Name *name);
NameType name_type_from_string(const char *n);
bool name_is_valid(const char *n);

27
test-engine.c
View File

@ -9,14 +9,14 @@
int main(int argc, char *argv[]) {
Manager *m = NULL;
Name *a = NULL, *b = NULL, *c = NULL, *d = NULL, *e = NULL, *g = NULL;
Name *a = NULL, *b = NULL, *c = NULL, *d = NULL, *e = NULL, *g = NULL, *h = NULL;
Job *j;
assert_se(chdir("test2") == 0);
assert_se(m = manager_new());
printf("Loaded1:\n");
printf("Load1:\n");
assert_se(manager_load_name(m, "a.service", &a) == 0);
assert_se(manager_load_name(m, "b.service", &b) == 0);
assert_se(manager_load_name(m, "c.service", &c) == 0);
@ -26,7 +26,7 @@ int main(int argc, char *argv[]) {
assert_se(manager_add_job(m, JOB_START, c, JOB_REPLACE, false, &j) == 0);
manager_dump_jobs(m, stdout, "\t");
printf("Loaded2:\n");
printf("Load2:\n");
manager_clear_jobs(m);
assert_se(manager_load_name(m, "d.service", &d) == 0);
assert_se(manager_load_name(m, "e.service", &e) == 0);
@ -44,7 +44,7 @@ int main(int argc, char *argv[]) {
assert_se(manager_add_job(m, JOB_START, e, JOB_FAIL, false, &j) == 0);
manager_dump_jobs(m, stdout, "\t");
printf("Loaded3:\n");
printf("Load3:\n");
assert_se(manager_load_name(m, "g.service", &g) == 0);
manager_dump_names(m, stdout, "\t");
@ -55,6 +55,25 @@ int main(int argc, char *argv[]) {
assert_se(manager_add_job(m, JOB_START, g, JOB_REPLACE, false, &j) == 0);
manager_dump_jobs(m, stdout, "\t");
printf("Test7: (Unmeargable job type, fail)\n");
assert_se(manager_add_job(m, JOB_STOP, g, JOB_FAIL, false, &j) == -EEXIST);
printf("Test8: (Mergeable job type, fail)\n");
assert_se(manager_add_job(m, JOB_RESTART, g, JOB_FAIL, false, &j) == 0);
manager_dump_jobs(m, stdout, "\t");
printf("Test9: (Unmeargable job type, replace)\n");
assert_se(manager_add_job(m, JOB_STOP, g, JOB_REPLACE, false, &j) == 0);
manager_dump_jobs(m, stdout, "\t");
printf("Load4:\n");
assert_se(manager_load_name(m, "h.service", &h) == 0);
manager_dump_names(m, stdout, "\t");
printf("Test10: (Unmeargable job type of auxiliary job, fail)\n");
assert_se(manager_add_job(m, JOB_START, h, JOB_FAIL, false, &j) == 0);
manager_dump_jobs(m, stdout, "\t");
manager_free(m);
return 0;