We should not start source vm automatically, if the error occured after target accessed disks, or if we failed to invalidate nodes.
Also, fix, that we need invalidate even if bdrv_inactivate_all() failed, as in this case it still may successfully inactivate some of the nodes. Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]> --- Hi all! It's an investigation on top of old thread https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg02355.html Either I'm missing something, or we need this patch. It's a draft, may be need to split it into 2-3 small patches. Still I'd like to get general approval at first, may be I'm doing something wrong. Also, there may be other migration failure cases like this. qapi/migration.json | 7 +++++-- migration/migration.c | 36 ++++++++++++++++++++++++------------ 2 files changed, 29 insertions(+), 14 deletions(-) diff --git a/qapi/migration.json b/qapi/migration.json index b7348d0c8b..90fa625cbb 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -125,6 +125,9 @@ # # @failed: some error occurred during migration process. # +# @failed-unrecoverable: postcopy failed after no return point, when disks may +# already be accessed by target Qemu process. (since 5.0) +# # @colo: VM is in the process of fault tolerance, VM can not get into this # state unless colo capability is enabled for migration. (since 2.8) # @@ -142,8 +145,8 @@ { 'enum': 'MigrationStatus', 'data': [ 'none', 'setup', 'cancelling', 'cancelled', 'active', 'postcopy-active', 'postcopy-paused', - 'postcopy-recover', 'completed', 'failed', 'colo', - 'pre-switchover', 'device', 'wait-unplug' ] } + 'postcopy-recover', 'completed', 'failed', 'failed-unrecoverable', + 'colo', 'pre-switchover', 'device', 'wait-unplug' ] } ## # @MigrationInfo: diff --git a/migration/migration.c b/migration/migration.c index 354ad072fa..00684fdef8 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -2576,7 +2576,14 @@ static int postcopy_start(MigrationState *ms) QEMUFile *fb; int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); int64_t bandwidth = migrate_max_postcopy_bandwidth(); - bool restart_block = false; + + /* + * recoverable_failure + * A failure happened early enough that we know the destination hasn't + * accessed block devices, so we're safe to recover. + */ + bool recoverable_failure = true; + bool inactivated = false; int cur_state = MIGRATION_STATUS_ACTIVE; if (!migrate_pause_before_switchover()) { migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE, @@ -2600,11 +2607,11 @@ static int postcopy_start(MigrationState *ms) goto fail; } + inactivated = true; ret = bdrv_inactivate_all(); if (ret < 0) { goto fail; } - restart_block = true; /* * Cause any non-postcopiable, but iterative devices to @@ -2682,7 +2689,7 @@ static int postcopy_start(MigrationState *ms) goto fail_closefb; } - restart_block = false; + recoverable_failure = false; /* Now send that blob */ if (qemu_savevm_send_packaged(ms->to_dst_file, bioc->data, bioc->usage)) { @@ -2716,26 +2723,28 @@ static int postcopy_start(MigrationState *ms) ret = qemu_file_get_error(ms->to_dst_file); if (ret) { error_report("postcopy_start: Migration stream errored"); - migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, - MIGRATION_STATUS_FAILED); + goto fail; } - return ret; + return 0; fail_closefb: qemu_fclose(fb); fail: migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE, - MIGRATION_STATUS_FAILED); - if (restart_block) { - /* A failure happened early enough that we know the destination hasn't - * accessed block devices, so we're safe to recover. - */ + recoverable_failure ? MIGRATION_STATUS_FAILED : + MIGRATION_STATUS_FAILED_UNRECOVERABLE); + if (recoverable_failure && inactivated) { Error *local_err = NULL; bdrv_invalidate_cache_all(&local_err); if (local_err) { error_report_err(local_err); + /* + * We failed to invalidate, so we must not start vm automatically. + * User may retry invalidation and start by cont qmp command. + */ + ms->vm_was_running = false; } } qemu_mutex_unlock_iothread(); @@ -3194,9 +3203,12 @@ static void migration_iteration_finish(MigrationState *s) s->vm_was_running = true; /* Fallthrough */ case MIGRATION_STATUS_FAILED: + case MIGRATION_STATUS_FAILED_UNRECOVERABLE: case MIGRATION_STATUS_CANCELLED: case MIGRATION_STATUS_CANCELLING: - if (s->vm_was_running) { + if (s->vm_was_running && + s->state != MIGRATION_STATUS_FAILED_UNRECOVERABLE) + { vm_start(); } else { if (runstate_check(RUN_STATE_FINISH_MIGRATE)) { -- 2.21.0
