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[Qemu-devel] Re: [PATCH 10/22] migration: Refactor and simplify error ch
From: |
Juan Quintela |
Subject: |
[Qemu-devel] Re: [PATCH 10/22] migration: Refactor and simplify error checking in migrate_fd_put_ready |
Date: |
Wed, 23 Feb 2011 11:08:54 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) |
Yoshiaki Tamura <address@hidden> wrote:
> 2011/2/23 Juan Quintela <address@hidden>:
>>
>> Signed-off-by: Juan Quintela <address@hidden>
>> ---
>> migration.c | 20 +++++++++-----------
>> 1 files changed, 9 insertions(+), 11 deletions(-)
>>
>> diff --git a/migration.c b/migration.c
>> index f015e02..641df9f 100644
>> --- a/migration.c
>> +++ b/migration.c
>> @@ -361,28 +361,26 @@ static void migrate_fd_put_ready(void *opaque)
>>
>> DPRINTF("iterate\n");
>> if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
>> - int state;
>> int old_vm_running = vm_running;
>>
>> DPRINTF("done iterating\n");
>> vm_stop(VMSTOP_MIGRATE);
>>
>> - if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
>> - if (old_vm_running) {
>> - vm_start();
>> - }
>> - state = MIG_STATE_ERROR;
>> + if (qemu_savevm_state_complete(s->mon, s->file) < 0) {
>> + migrate_fd_error(s);
>> } else {
>> - state = MIG_STATE_COMPLETED;
>> + if (migrate_fd_cleanup(s) < 0) {
>> + migrate_fd_error(s);
>> + } else {
>> + s->state = MIG_STATE_COMPLETED;
>> + notifier_list_notify(&migration_state_notifiers);
>> + }
>> }
>> - if (migrate_fd_cleanup(s) < 0) {
>> + if (s->get_status(s) != MIG_STATE_COMPLETED) {
>> if (old_vm_running) {
>> vm_start();
>> }
>
> This part, although it's not fair to ask you, but calling
> vm_start when != MIG_STATE_COMPLETED terrifies me because just
> failing migrate_fd_cleanup (mostly calling qemu_fclose) may cause
> split brain between src/dst. Although I haven't encountered this
> situation, just having stopped VMs on both sides is safer.
I see your pain. I am not happy at all, but this was integrated by
Anthony to fix this bug:
commit 41ef56e61153d7bd27d34a634633bb51b1c5988d
Author: Anthony Liguori <address@hidden>
Date: Wed Jun 2 14:55:25 2010 -0500
migration: respect exit status with exec:
This fixes https://bugs.launchpad.net/qemu/+bug/391879
I think that it fixes that bug, but it makes me un-easy to restart vm if
there is a failure in migrate_fd_cleanup(). As I didn't wanted to
change behaviour with this series, I left it as it was.
Next on ToDo list is to do something sensible with errors, just now we
are not very good at handling them.
Later, Juan.
- [Qemu-devel] [PATCH 06/22] migration: Make all posible migration functions static, (continued)
- [Qemu-devel] [PATCH 06/22] migration: Make all posible migration functions static, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 08/22] migration: Check that migration is active before cancel it, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 09/22] migration: Introduce MIG_STATE_NONE, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 07/22] migration: move migrate_create_state to do_migrate, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 10/22] migration: Refactor and simplify error checking in migrate_fd_put_ready, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 11/22] migration: Introduce migrate_fd_completed() for consistenncy, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 12/22] migration: Use migrate_fd_error() in last place that set status to ERROR, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 13/22] migration: Our release callback was just free, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 15/22] migration: Remove migration cancel() callback, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 14/22] migration: Remove get_status() accessor, Juan Quintela, 2011/02/22
- [Qemu-devel] [PATCH 16/22] migration: Move exported functions to the end of the file, Juan Quintela, 2011/02/22