From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753206AbaCHM7v (ORCPT ); Sat, 8 Mar 2014 07:59:51 -0500 Received: from mail-pa0-f53.google.com ([209.85.220.53]:37396 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752046AbaCHM7Z (ORCPT ); Sat, 8 Mar 2014 07:59:25 -0500 From: Roman Pen Cc: Roman Peniaev , David Woodhouse , Brian Norris , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [v2 PATCH 1/1] mtd: mtd_blkdevs: handle REQ_FLUSH request and do explicit flush of writeback buffer Date: Sat, 8 Mar 2014 21:59:14 +0900 Message-Id: <1394283554-27423-1-git-send-email-r.peniaev@gmail.com> X-Mailer: git-send-email 1.8.5.2 To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Roman Peniaev mtd_blkdevs is device with volatile cache (writeback buffer), so it should support REQ_FLUSH to do explicit flush. Without this patch 'sync' does not guarantee that writeback buffer will be flushed on disk in case of power off, e.g.: $ cp some_file /mnt $ sync ### POWER OFF In case of this sequence writeback buffer will not be flushed on disk. This patch fixes this behaviour and explicitly reports to block layer that flush requests are being supported. Signed-off-by: Roman Peniaev CC: David Woodhouse CC: Brian Norris CC: linux-mtd@lists.infradead.org CC: linux-kernel@vger.kernel.org --- drivers/mtd/mtd_blkdevs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 5073cbc..b2970a0 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -89,6 +89,9 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr, if (req->cmd_type != REQ_TYPE_FS) return -EIO; + if (req->cmd_flags & REQ_FLUSH) + return tr->flush(dev); + if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > get_capacity(req->rq_disk)) return -EIO; @@ -409,6 +412,9 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) if (!new->rq) goto error3; + if (tr->flush) + blk_queue_flush(new->rq, REQ_FLUSH); + new->rq->queuedata = new; blk_queue_logical_block_size(new->rq, tr->blksize); -- 1.8.5.2