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migration: Add Error** argument to qemu_savevm_state_setup()

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This prepares ground for the changes coming next which add an Error**
argument to the .save_setup() handler. Callers of qemu_savevm_state_setup()
now handle the error and fail earlier setting the migration state from
MIGRATION_STATUS_SETUP to MIGRATION_STATUS_FAILED.

In qemu_savevm_state(), move the cleanup to preserve the error
reported by .save_setup() handlers.

Since the previous behavior was to ignore errors at this step of
migration, this change should be examined closely to check that
cleanups are still correctly done.

Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240320064911.545001-7-clg@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
This commit is contained in:
Cédric Le Goater 2024-03-20 07:49:02 +01:00 committed by Peter Xu
parent 6138d43ab2
commit 057a20099b
3 changed files with 47 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
migration/migration.c
View File

@ -3431,6 +3431,8 @@ static void *migration_thread(void *opaque)
int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
MigThrError thr_error;
bool urgent = false;
Error *local_err = NULL;
int ret;
thread = migration_threads_add("live_migration", qemu_get_thread_id());
@ -3474,12 +3476,24 @@ static void *migration_thread(void *opaque)
}
bql_lock();
qemu_savevm_state_setup(s->to_dst_file);
ret = qemu_savevm_state_setup(s->to_dst_file, &local_err);
bql_unlock();
qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_ACTIVE);
/*
* Handle SETUP failures after waiting for virtio-net-failover
* devices to unplug. This to preserve migration state transitions.
*/
if (ret) {
migrate_set_error(s, local_err);
error_free(local_err);
migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_FAILED);
goto out;
}
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
trace_migration_thread_setup_complete();
@ -3553,6 +3567,8 @@ static void *bg_migration_thread(void *opaque)
MigThrError thr_error;
QEMUFile *fb;
bool early_fail = true;
Error *local_err = NULL;
int ret;
rcu_register_thread();
object_ref(OBJECT(s));
@ -3586,12 +3602,24 @@ static void *bg_migration_thread(void *opaque)
bql_lock();
qemu_savevm_state_header(s->to_dst_file);
qemu_savevm_state_setup(s->to_dst_file);
ret = qemu_savevm_state_setup(s->to_dst_file, &local_err);
bql_unlock();
qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
MIGRATION_STATUS_ACTIVE);
/*
* Handle SETUP failures after waiting for virtio-net-failover
* devices to unplug. This to preserve migration state transitions.
*/
if (ret) {
migrate_set_error(s, local_err);
error_free(local_err);
migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_FAILED);
goto fail_setup;
}
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
trace_migration_thread_setup_complete();
@ -3660,6 +3688,7 @@ fail:
bql_unlock();
}
fail_setup:
bg_migration_iteration_finish(s);
qemu_fclose(fb);

26
migration/savevm.c
View File

@ -1310,11 +1310,11 @@ int qemu_savevm_state_prepare(Error **errp)
return 0;
}
void qemu_savevm_state_setup(QEMUFile *f)
int qemu_savevm_state_setup(QEMUFile *f, Error **errp)
{
ERRP_GUARD();
MigrationState *ms = migrate_get_current();
SaveStateEntry *se;
Error *local_err = NULL;
int ret = 0;
json_writer_int64(ms->vmdesc, "page_size", qemu_target_page_size());
@ -1323,10 +1323,9 @@ void qemu_savevm_state_setup(QEMUFile *f)
trace_savevm_state_setup();
QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
if (se->vmsd && se->vmsd->early_setup) {
ret = vmstate_save(f, se, ms->vmdesc, &local_err);
ret = vmstate_save(f, se, ms->vmdesc, errp);
if (ret) {
migrate_set_error(ms, local_err);
error_report_err(local_err);
migrate_set_error(ms, *errp);
qemu_file_set_error(f, ret);
break;
}
@ -1346,18 +1345,19 @@ void qemu_savevm_state_setup(QEMUFile *f)
ret = se->ops->save_setup(f, se->opaque);
save_section_footer(f, se);
if (ret < 0) {
error_setg(errp, "failed to setup SaveStateEntry with id(name): "
"%d(%s): %d", se->section_id, se->idstr, ret);
qemu_file_set_error(f, ret);
break;
}
}
if (ret) {
return;
return ret;
}
if (precopy_notify(PRECOPY_NOTIFY_SETUP, &local_err)) {
error_report_err(local_err);
}
/* TODO: Should we check that errp is set in case of failure ? */
return precopy_notify(PRECOPY_NOTIFY_SETUP, errp);
}
int qemu_savevm_state_resume_prepare(MigrationState *s)
@ -1725,7 +1725,10 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
ms->to_dst_file = f;
qemu_savevm_state_header(f);
qemu_savevm_state_setup(f);
ret = qemu_savevm_state_setup(f, errp);
if (ret) {
goto cleanup;
}
while (qemu_file_get_error(f) == 0) {
if (qemu_savevm_state_iterate(f, false) > 0) {
@ -1738,10 +1741,11 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
qemu_savevm_state_complete_precopy(f, false, false);
ret = qemu_file_get_error(f);
}
qemu_savevm_state_cleanup();
if (ret != 0) {
error_setg_errno(errp, -ret, "Error while writing VM state");
}
cleanup:
qemu_savevm_state_cleanup();
if (ret != 0) {
status = MIGRATION_STATUS_FAILED;

2
migration/savevm.h
View File

@ -32,7 +32,7 @@
bool qemu_savevm_state_blocked(Error **errp);
void qemu_savevm_non_migratable_list(strList **reasons);
int qemu_savevm_state_prepare(Error **errp);
void qemu_savevm_state_setup(QEMUFile *f);
int qemu_savevm_state_setup(QEMUFile *f, Error **errp);
bool qemu_savevm_state_guest_unplug_pending(void);
int qemu_savevm_state_resume_prepare(MigrationState *s);
void qemu_savevm_state_header(QEMUFile *f);