* Greg Kurz (gk...@linux.vnet.ibm.com) wrote:
> We currently have an error path during migration that can cause
> the source QEMU to abort:
Hmm, wasn't there something similar recently, sorry I can't remember the
details, but
cc'ing some block people who might remember.
Dave
>
> 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 <gk...@linux.vnet.ibm.com>
> ---
> migration/migration.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 991313a8629a..5726959ddfd9 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1568,8 +1568,17 @@ static void migration_completion(MigrationState *s,
> int current_active_state,
> ret = bdrv_inactivate_all();
> }
> if (ret >= 0) {
> + Error *local_err = NULL;
> +
> qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
> qemu_savevm_state_complete_precopy(s->to_dst_file, false);
> +
> + if (qemu_file_get_error(s->to_dst_file)) {
> + bdrv_invalidate_cache_all(&local_err);
> + if (local_err) {
> + error_report_err(local_err);
> + }
> + }
> }
> }
> qemu_mutex_unlock_iothread();
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
