block: Use bdrv_do_drain_begin/end in bdrv_drain_all()

bdrv_do_drain_begin/end() implement already everything that
bdrv_drain_all_begin/end() need and currently still do manually: Disable
external events, call parent drain callbacks, call block driver
callbacks.

It also does two more things:

The first is incrementing bs->quiesce_counter. bdrv_drain_all() already
stood out in the test case by behaving different from the other drain
variants. Adding this is not only safe, but in fact a bug fix.

The second is calling bdrv_drain_recurse(). We already do that later in
the same function in a loop, so basically doing an early first iteration
doesn't hurt.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 2 insertions, 8 deletions

diff --git a/block/io.c b/block/io.c
index 5f286bc..b355009 100644
--- a/block/io.c
+++ b/block/io.c
@@ -413,11 +413,8 @@ void bdrv_drain_all_begin(void)
     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
         AioContext *aio_context = bdrv_get_aio_context(bs);
 
-        /* Stop things in parent-to-child order */
         aio_context_acquire(aio_context);
-        aio_disable_external(aio_context);
-        bdrv_parent_drained_begin(bs, NULL);
-        bdrv_drain_invoke(bs, true, true);
+        bdrv_do_drained_begin(bs, true, NULL);
         aio_context_release(aio_context);
 
         if (!g_slist_find(aio_ctxs, aio_context)) {
@@ -458,11 +455,8 @@ void bdrv_drain_all_end(void)
     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
         AioContext *aio_context = bdrv_get_aio_context(bs);
 
-        /* Re-enable things in child-to-parent order */
         aio_context_acquire(aio_context);
-        bdrv_drain_invoke(bs, false, true);
-        bdrv_parent_drained_end(bs, NULL);
-        aio_enable_external(aio_context);
+        bdrv_do_drained_end(bs, true, NULL);
         aio_context_release(aio_context);
     }
 }