From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42590) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uu0yB-0003Hp-6A for qemu-devel@nongnu.org; Tue, 02 Jul 2013 09:50:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uu0y7-0002fO-KY for qemu-devel@nongnu.org; Tue, 02 Jul 2013 09:50:11 -0400 From: Stefan Hajnoczi Date: Tue, 2 Jul 2013 15:36:25 +0200 Message-Id: <1372772185-10958-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH v2] 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 , qemu-stable@nongnu.org, 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. Call bdrv_drain_all() again for safety as the final step after bdrv_flush(). This should not be necessary but we can be paranoid here in case bdrv_flush() left I/O pending. Cc: qemu-stable@nongnu.org Signed-off-by: Stefan Hajnoczi --- v2: * Drain after block_job_cancel_sync() [kwolf] block.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index 6c493ad..183fec8 100644 --- a/block.c +++ b/block.c @@ -1358,11 +1358,12 @@ void bdrv_reopen_abort(BDRVReopenState *reopen_state) void bdrv_close(BlockDriverState *bs) { - bdrv_flush(bs); if (bs->job) { block_job_cancel_sync(bs->job); } - bdrv_drain_all(); + bdrv_drain_all(); /* complete I/O */ + bdrv_flush(bs); + bdrv_drain_all(); /* in case flush left pending I/O */ notifier_list_notify(&bs->close_notifiers, bs); if (bs->drv) { -- 1.8.1.4