From 057a20099b62c5ac3c925f3fe12bdedac96e647b Mon Sep 17 00:00:00 2001 From: =?utf8?q?C=C3=A9dric=20Le=20Goater?= Date: Wed, 20 Mar 2024 07:49:02 +0100 Subject: [PATCH] migration: Add Error** argument to qemu_savevm_state_setup() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Peter Xu Link: https://lore.kernel.org/r/20240320064911.545001-7-clg@redhat.com Signed-off-by: Peter Xu --- migration/migration.c | 33 +++++++++++++++++++++++++++++++-- migration/savevm.c | 26 +++++++++++++++----------- migration/savevm.h | 2 +- 3 files changed, 47 insertions(+), 14 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index 86bf76e925..696762bc64 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -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); diff --git a/migration/savevm.c b/migration/savevm.c index 6252fc37b7..327e9b346e 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -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; diff --git a/migration/savevm.h b/migration/savevm.h index 74669733dd..9ec96a995c 100644 --- a/migration/savevm.h +++ b/migration/savevm.h @@ -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); -- 2.11.4.GIT