From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41140) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UnQch-0001Sz-RA for qemu-devel@nongnu.org; Fri, 14 Jun 2013 05:48:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UnQcf-0000b3-1c for qemu-devel@nongnu.org; Fri, 14 Jun 2013 05:48:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52664) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UnQce-0000av-Qf for qemu-devel@nongnu.org; Fri, 14 Jun 2013 05:48:44 -0400 From: Stefan Hajnoczi Date: Fri, 14 Jun 2013 11:48:21 +0200 Message-Id: <1371203313-26490-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1371203313-26490-1-git-send-email-stefanha@redhat.com> References: <1371203313-26490-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [RFC 01/13] block: fix bdrv_flush() ordering in bdrv_close() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Paolo Bonzini , Anthony Liguori , Ping Fan Liu , Stefan Hajnoczi Since 80ccf93b we flush the block device during close. The bdrv_drain_all() call should come before bdrv_flush() to ensure guest write requests have completed. Otherwise we may miss pending writes when flushing. However, there is still a slight change that cancelling a blockjob or doing bdrv_flush() might leave an I/O request running, so call bdrv_drain_all() again for safety as the final step. Signed-off-by: Stefan Hajnoczi --- block.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index 79ad33d..1c9df27 100644 --- a/block.c +++ b/block.c @@ -1357,11 +1357,12 @@ void bdrv_reopen_abort(BDRVReopenState *reopen_state) void bdrv_close(BlockDriverState *bs) { - bdrv_flush(bs); + bdrv_drain_all(); /* complete guest I/O */ if (bs->job) { block_job_cancel_sync(bs->job); } - bdrv_drain_all(); + bdrv_flush(bs); + bdrv_drain_all(); /* in case blockjob or flush started I/O */ notifier_list_notify(&bs->close_notifiers, bs); if (bs->drv) { -- 1.8.1.4