Draining is not necessary, I/O can happen as soon as the commit coroutine yields. Draining can be necessary before reopening the file for read/write, or while modifying the backing file chain, but that is done separately in bdrv_reopen_multiple or bdrv_close; this particular bdrv_drain_all does nothing for that.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> --- blockdev.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/blockdev.c b/blockdev.c index d506a70..aee0395 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2355,9 +2355,6 @@ void qmp_block_commit(const char *device, aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - /* drain all i/o before commits */ - bdrv_drain_all(); - if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, errp)) { goto out; } -- 2.4.1