From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755394Ab2ASIw2 (ORCPT ); Thu, 19 Jan 2012 03:52:28 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45374 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752621Ab2ASIw1 (ORCPT ); Thu, 19 Jan 2012 03:52:27 -0500 Message-ID: <4F17D95E.7070403@redhat.com> Date: Thu, 19 Jan 2012 08:50:38 +0000 From: Niels de Vos User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 MIME-Version: 1.0 To: Jens Axboe CC: linux-kernel@vger.kernel.org, Niels de Vos , "Bryn M. Reeves" Subject: [PATCH] block: Invalidate the cache for a parent block-device if blkdev_issue_flush() was called for a partition X-Enigmail-Version: 1.3.3 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Executing a BLKFLSBUF-ioctl on a partition flushes the caches for that partition but reading data through the parent device will still return the old cached data. The cache for the block-device is not synced if the block-device is kept open (due to a mounted partition, for example). Only when all users for the disk have exited, the cache for the disk is made consistent again. Calling invalidate_bdev() on the parent block-device in case blkdev_issue_flush() was called for a partition fixes this. The problem can be worked around by forcing the caches to be flushed with either # blockdev --flushbufs ${dev_disk} or # echo 3 > /proc/sys/vm/drop_caches CC: Bryn M. Reeves Signed-off-by: Niels de Vos --- block/blk-flush.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/block/blk-flush.c b/block/blk-flush.c index 720ad60..e876f8e 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -448,6 +448,9 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask, if (!bio_flagged(bio, BIO_UPTODATE)) ret = -EIO; + else if (bdev != bdev->bd_contains) + /* invalidate parent block_device */ + invalidate_bdev(bdev->bd_contains); bio_put(bio); return ret; -- 1.7.6.5