On Tue, 05/19 10:04, Paolo Bonzini wrote: > On 19/05/2015 13:49, Fam Zheng wrote: > > When block job mirror is finished, the source and target is synced. But > > we call bdrv_swap() later in main loop bh. If the guest write before > > that, target will not get the new data. > > This is too late. As a rule, the blocker must be established before > calling bdrv_drain, and removed on the next yield (in this case, before > the assignment to last_pause_ns).
I don't understand. If the blocker is removed before mirror_run returns, wouldn't more device IO already hit source image by the time mirror_exit runs? Fam > > Paolo > > > Reported-by: Wen Congyang <we...@cn.fujitsu.com> > > Signed-off-by: Fam Zheng <f...@redhat.com> > > --- > > block/mirror.c | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/block/mirror.c b/block/mirror.c > > index 58f391a..d96403b 100644 > > --- a/block/mirror.c > > +++ b/block/mirror.c > > @@ -320,6 +320,8 @@ static void mirror_drain(MirrorBlockJob *s) > > > > typedef struct { > > int ret; > > + /* Use to pause device IO during mirror exit */ > > + Error *blocker; > > } MirrorExitData; > > > > static void mirror_exit(BlockJob *job, void *opaque) > > @@ -328,6 +330,8 @@ static void mirror_exit(BlockJob *job, void *opaque) > > MirrorExitData *data = opaque; > > AioContext *replace_aio_context = NULL; > > > > + bdrv_op_unblock(s->common.bs, BLOCK_OP_TYPE_DEVICE_IO, data->blocker); > > + error_free(data->blocker); > > if (s->to_replace) { > > replace_aio_context = bdrv_get_aio_context(s->to_replace); > > aio_context_acquire(replace_aio_context); > > @@ -563,8 +567,10 @@ immediate_exit: > > bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); > > bdrv_iostatus_disable(s->target); > > > > - data = g_malloc(sizeof(*data)); > > + data = g_malloc0(sizeof(*data)); > > data->ret = ret; > > + error_setg(&data->blocker, "mirror job exiting"); > > + bdrv_op_block(bs, BLOCK_OP_TYPE_DEVICE_IO, data->blocker); > > block_job_defer_to_main_loop(&s->common, mirror_exit, data); > > } > > > >