| Message ID | 1432102576-6637-14-git-send-email-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 20/05/2015 08:16, Fam Zheng wrote: > > 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); Why here and not after the "if (s->should_complete && data->ret == 0) { ... }"? The commit message says "unblock it after bdrv_swap()." This is the only remaining issue. Paolo
On Wed, 05/20 08:32, Paolo Bonzini wrote: > > > On 20/05/2015 08:16, Fam Zheng wrote: > > > > 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); > > Why here and not after the "if (s->should_complete && data->ret == 0) { > ... }"? The commit message says "unblock it after bdrv_swap()." > > This is the only remaining issue. Ouch, I thought I did that... It absolutely has to go after bdrv_swap(). Fam
diff --git a/block/mirror.c b/block/mirror.c index 58f391a..f400456 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); @@ -376,6 +380,8 @@ static void coroutine_fn mirror_run(void *opaque) checking for a NULL string */ int ret = 0; int n; + data = g_malloc0(sizeof(*data)); + error_setg(&data->blocker, "mirror job exiting"); if (block_job_is_cancelled(&s->common)) { goto immediate_exit; @@ -521,6 +527,7 @@ static void coroutine_fn mirror_run(void *opaque) * mirror_populate runs. */ trace_mirror_before_drain(s, cnt); + bdrv_op_block(bs, BLOCK_OP_TYPE_DEVICE_IO, data->blocker); bdrv_drain(bs); cnt = bdrv_get_dirty_count(s->dirty_bitmap); } @@ -543,6 +550,7 @@ static void coroutine_fn mirror_run(void *opaque) s->common.cancelled = false; break; } + bdrv_op_unblock(bs, BLOCK_OP_TYPE_DEVICE_IO, data->blocker); last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); } @@ -563,7 +571,6 @@ immediate_exit: bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); bdrv_iostatus_disable(s->target); - data = g_malloc(sizeof(*data)); data->ret = ret; block_job_defer_to_main_loop(&s->common, mirror_exit, data); }
When mirror should complete, the source and target are in sync. But we call bdrv_swap() only a while later in the main loop bh. If the guest writes something before that, target will not get the new data. Block "device IO" before bdrv_drain and unblock it after bdrw_swap(). Reported-by: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: Fam Zheng <famz@redhat.com> --- block/mirror.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)