From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86FCFC4338F for ; Mon, 2 Aug 2021 19:54:20 +0000 (UTC) Received: from pdx1-mailman02.dreamhost.com (pdx1-mailman02.dreamhost.com [64.90.62.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4B88260F36 for ; Mon, 2 Aug 2021 19:54:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4B88260F36 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.lustre.org Received: from pdx1-mailman02.dreamhost.com (localhost [IPv6:::1]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id B3DBD34FCF1; Mon, 2 Aug 2021 12:54:18 -0700 (PDT) Received: from smtp4.ccs.ornl.gov (smtp4.ccs.ornl.gov [160.91.203.40]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id 4A36635286A for ; Mon, 2 Aug 2021 12:50:55 -0700 (PDT) Received: from star.ccs.ornl.gov (star.ccs.ornl.gov [160.91.202.134]) by smtp4.ccs.ornl.gov (Postfix) with ESMTP id 516861007A8E; Mon, 2 Aug 2021 15:50:53 -0400 (EDT) Received: by star.ccs.ornl.gov (Postfix, from userid 2004) id 48919C2F50; Mon, 2 Aug 2021 15:50:53 -0400 (EDT) From: James Simmons To: Andreas Dilger , Oleg Drokin , NeilBrown Date: Mon, 2 Aug 2021 15:50:22 -0400 Message-Id: <1627933851-7603-3-git-send-email-jsimmons@infradead.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1627933851-7603-1-git-send-email-jsimmons@infradead.org> References: <1627933851-7603-1-git-send-email-jsimmons@infradead.org> Subject: [lustre-devel] [PATCH 02/25] lustre: llite: No locked parallel DIO X-BeenThere: lustre-devel@lists.lustre.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "For discussing Lustre software development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lustre Development List MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: lustre-devel-bounces@lists.lustre.org Sender: "lustre-devel" From: Patrick Farrell If we are doing locked DIO, the OSC & LDLM locks are released at the end of cl_io_loop, ie, before we wait for parallel DIO at the llite layer. This is problematic because the locks are released before i/o done using them is complete; this can lead to data inconsistencies. (And at least one LBUG, see LU-14805.) The easiest solution for now is only do parallel DIO when working lockless (which is the default; DIO only switches to locked to manage conflicts with buffered i/o). This problem & fix apply to AIO as well as parallel DIO. WC-bug-id: https://jira.whamcloud.com/browse/LU-14805 Lustre-commit: 0f8db7e06abbc341 ("LU-14805 llite: No locked parallel DIO") Signed-off-by: Patrick Farrell Reviewed-on: https://review.whamcloud.com/44131 Reviewed-by: Wang Shilong Reviewed-by: Andreas Dilger Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- fs/lustre/llite/rw26.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/lustre/llite/rw26.c b/fs/lustre/llite/rw26.c index ba9c070..0d72c3e 100644 --- a/fs/lustre/llite/rw26.c +++ b/fs/lustre/llite/rw26.c @@ -410,10 +410,19 @@ static ssize_t ll_direct_IO(struct kiocb *iocb, struct iov_iter *iter) else vio->u.readwrite.vui_read += tot_bytes; - /* If async dio submission is not allowed, we must wait here. */ - if (is_sync_kiocb(iocb) && !io->ci_parallel_dio) { + /* We cannot do async submission - for AIO or regular DIO - unless + * lockless because it causes us to release the lock early. + * + * There are also several circumstances in which we must disable + * parallel DIO, so we check if it is enabled. + * + * The check for "is_sync_kiocb" excludes AIO, which does not need to + * be disabled in these situations. + */ + if (io->ci_dio_lock || (is_sync_kiocb(iocb) && !io->ci_parallel_dio)) { ssize_t rc2; + /* Wait here rather than doing async submission */ rc2 = cl_sync_io_wait_recycle(env, &aio->cda_sync, 0, 0); if (result == 0 && rc2) result = rc2; -- 1.8.3.1 _______________________________________________ lustre-devel mailing list lustre-devel@lists.lustre.org http://lists.lustre.org/listinfo.cgi/lustre-devel-lustre.org