From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52317) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zp9Rt-0002C3-C2 for qemu-devel@nongnu.org; Thu, 22 Oct 2015 02:34:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zp9Rq-0008Ky-4P for qemu-devel@nongnu.org; Thu, 22 Oct 2015 02:34:05 -0400 From: Fam Zheng Date: Thu, 22 Oct 2015 14:32:59 +0800 Message-Id: <1445495580-32129-12-git-send-email-famz@redhat.com> In-Reply-To: <1445495580-32129-1-git-send-email-famz@redhat.com> References: <1445495580-32129-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v6 11/12] qed: Implement .bdrv_drain List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, pbonzini@redhat.com, jcody@redhat.com, stefanha@redhat.com, qemu-block@nongnu.org The "need_check_timer" is used to clear the "NEED_CHECK" flag in the image header after a grace period once metadata update has finished. In compliance to the bdrv_drain semantics we should make sure it remains deleted once .bdrv_drain is called. We cannot reuse qed_need_check_timer_cb because it calls bdrv_aio_flush with a completion callback that starts more I/O, bdrv_drain cannot cope with this. Also the assertions in qed_need_check_timer_cb and qed_unplug_allocating_write_reqs are not guaranteed in the case of bdrv_qed_drain. Signed-off-by: Fam Zheng --- block/qed.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/block/qed.c b/block/qed.c index 5ea05d4..d63a7de 100644 --- a/block/qed.c +++ b/block/qed.c @@ -375,6 +375,20 @@ static void bdrv_qed_attach_aio_context(BlockDriverState *bs, } } +static void bdrv_qed_drain(BlockDriverState *bs) +{ + BDRVQEDState *s = bs->opaque; + int ret; + + /* Cancel timer and start doing I/O that were meant to happen when it + * fires, that way we get bdrv_drain() taking care of the requests + * correctly. */ + qed_cancel_need_check_timer(s); + qed_plug_allocating_write_reqs(s); + ret = bdrv_flush(s->bs); + qed_clear_need_check(s, ret); +} + static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { @@ -1676,6 +1690,7 @@ static BlockDriver bdrv_qed = { .bdrv_check = bdrv_qed_check, .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, + .bdrv_drain = bdrv_qed_drain, }; static void bdrv_qed_init(void) -- 2.4.3