Patchwork [PULL,7/8] migration: Fail migration on bdrv_flush_all() error

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Submitter Kevin Wolf
Date July 15, 2013, 11:16 a.m.
Message ID <1373887000-4488-8-git-send-email-kwolf@redhat.com>
Download mbox | patch
Permalink /patch/259010/
State New
Headers show

Comments

Kevin Wolf - July 15, 2013, 11:16 a.m.
If bdrv_flush_all() returns an error, there is an inconsistency in the
view of an image file between the source and the destination host.
Completing the migration would lead to corruption. Better abort
migration in this case.

To reproduce this case, try the following (ensures that there is
something to flush, and then fails that flush):

$ qemu-img create -f qcow2 test.qcow2 1G
$ cat blkdebug.cfg
[inject-error]
event = "flush_to_os"
errno = "5"
$ qemu-system-x86_64 -hda blkdebug:blkdebug.cfg:test.qcow2 -monitor stdio
(qemu) qemu-io ide0-hd0 "write 0 4k"
(qemu) migrate ...

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 migration.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

Patch

diff --git a/migration.c b/migration.c
index 635a7e7..0681d8e 100644
--- a/migration.c
+++ b/migration.c
@@ -527,15 +527,26 @@  static void *migration_thread(void *opaque)
             if (pending_size && pending_size >= max_size) {
                 qemu_savevm_state_iterate(s->file);
             } else {
+                int ret;
+
                 DPRINTF("done iterating\n");
                 qemu_mutex_lock_iothread();
                 start_time = qemu_get_clock_ms(rt_clock);
                 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
                 old_vm_running = runstate_is_running();
-                vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
-                qemu_file_set_rate_limit(s->file, INT_MAX);
-                qemu_savevm_state_complete(s->file);
+
+                ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
+                if (ret >= 0) {
+                    qemu_file_set_rate_limit(s->file, INT_MAX);
+                    qemu_savevm_state_complete(s->file);
+                }
                 qemu_mutex_unlock_iothread();
+
+                if (ret < 0) {
+                    migrate_finish_set_state(s, MIG_STATE_ERROR);
+                    break;
+                }
+
                 if (!qemu_file_get_error(s->file)) {
                     migrate_finish_set_state(s, MIG_STATE_COMPLETED);
                     break;