From patchwork Fri Jul 20 13:05:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Wilck X-Patchwork-Id: 10537507 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5C02D602CA for ; Fri, 20 Jul 2018 13:41:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 55DDA296CD for ; Fri, 20 Jul 2018 13:41:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4A1E12971E; Fri, 20 Jul 2018 13:41:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F274A296CD for ; Fri, 20 Jul 2018 13:41:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731981AbeGTO3n (ORCPT ); Fri, 20 Jul 2018 10:29:43 -0400 Received: from smtp2.provo.novell.com ([137.65.250.81]:36013 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731565AbeGTO3n (ORCPT ); Fri, 20 Jul 2018 10:29:43 -0400 Received: from apollon.suse.de.de (prv-ext-foundry1int.gns.novell.com [137.65.251.240]) by smtp2.provo.novell.com with ESMTP (TLS encrypted); Fri, 20 Jul 2018 07:41:13 -0600 From: Martin Wilck To: Jens Axboe , Jan Kara , Ming Lei , Christoph Hellwig Cc: Hannes Reinecke , Johannes Thumshirn , Kent Overstreet , linux-block@vger.kernel.org, Martin Wilck Subject: [PATCH v4 4/4] blkdev: __blkdev_direct_IO_simple: make sure to fill up the bio Date: Fri, 20 Jul 2018 15:05:52 +0200 Message-Id: <20180720130552.21432-5-mwilck@suse.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180720130552.21432-1-mwilck@suse.com> References: <20180720130552.21432-1-mwilck@suse.com> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP bio_iov_iter_get_pages() returns only pages for a single non-empty segment of the input iov_iter's iovec. This may be less than the number of pages __blkdev_direct_IO_simple() is supposed to process. Call the new bio_iov_iter_get_all_pages() helper instead to avoid short reads or writes. Otherwise, __generic_file_write_iter() falls back to buffered writes, which has been observed to cause data corruption in certain workloads. Fixes: 72ecad22d9f1 ("block: support a full bio worth of IO for simplified bdev direct-io") Signed-off-by: Martin Wilck --- fs/block_dev.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index aba2541..010708a 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -219,9 +219,16 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, bio.bi_end_io = blkdev_bio_end_io_simple; bio.bi_ioprio = iocb->ki_ioprio; - ret = bio_iov_iter_get_pages(&bio, iter); + ret = bio_iov_iter_get_all_pages(&bio, iter); if (unlikely(ret)) goto out; + + /* + * Our bi_io_vec should be big enough to hold all data from the + * iov_iter, as this has been checked before calling this function. + */ + WARN_ON_ONCE(iov_iter_count(iter)); + ret = bio.bi_iter.bi_size; if (iov_iter_rw(iter) == READ) {