From fe904ea8242cbae2d7e69c052c754b8f5f1ba1d6 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Wed, 18 May 2016 15:44:36 +0200 Subject: migration: regain control of images when migration fails to complete We currently have an error path during migration that can cause the source QEMU to abort: migration_thread() migration_completion() runstate_is_running() ----------------> true if guest is running bdrv_inactivate_all() ----------------> inactivate images qemu_savevm_state_complete_precopy() ... qemu_fflush() socket_writev_buffer() --------> error because destination fails qemu_fflush() -------------------> set error on migration stream migration_completion() -----------------> set migrate state to FAILED migration_thread() -----------------------> break migration loop vm_start() -----------------------------> restart guest with inactive images and you get: qemu-system-ppc64: socket_writev_buffer: Got err=104 for (32768/18446744073709551615) qemu-system-ppc64: /home/greg/Work/qemu/qemu-master/block/io.c:1342:bdrv_co_do_pwritev: Assertion `!(bs->open_flags & 0x0800)' failed. Aborted (core dumped) If we try postcopy with a similar scenario, we also get the writev error message but QEMU leaves the guest paused because entered_postcopy is true. We could possibly do the same with precopy and leave the guest paused. But since the historical default for migration errors is to restart the source, this patch adds a call to bdrv_invalidate_cache_all() instead. Signed-off-by: Greg Kurz Message-Id: <146357896785.6003.11983081732454362715.stgit@bahia.huguette.org> Signed-off-by: Amit Shah --- migration/migration.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'migration') diff --git a/migration/migration.c b/migration/migration.c index 721d010fde..f5327e8c0a 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1606,19 +1606,32 @@ static void migration_completion(MigrationState *s, int current_active_state, rp_error = await_return_path_close_on_source(s); trace_migration_completion_postcopy_end_after_rp(rp_error); if (rp_error) { - goto fail; + goto fail_invalidate; } } if (qemu_file_get_error(s->to_dst_file)) { trace_migration_completion_file_err(); - goto fail; + goto fail_invalidate; } migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_COMPLETED); return; +fail_invalidate: + /* If not doing postcopy, vm_start() will be called: let's regain + * control on images. + */ + if (s->state == MIGRATION_STATUS_ACTIVE) { + Error *local_err = NULL; + + bdrv_invalidate_cache_all(&local_err); + if (local_err) { + error_report_err(local_err); + } + } + fail: migrate_set_state(&s->state, current_active_state, MIGRATION_STATUS_FAILED); -- cgit v1.2.3