From patchwork Sun Oct 14 18:58:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Simmons X-Patchwork-Id: 10640807 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 048151508 for ; Sun, 14 Oct 2018 18:58:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AAA8C2951D for ; Sun, 14 Oct 2018 18:58:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9ED2429527; Sun, 14 Oct 2018 18:58:34 +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=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from pdx1-mailman02.dreamhost.com (pdx1-mailman02.dreamhost.com [64.90.62.194]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 4BA322951D for ; Sun, 14 Oct 2018 18:58:34 +0000 (UTC) Received: from pdx1-mailman02.dreamhost.com (localhost [IPv6:::1]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id B42E821F85C; Sun, 14 Oct 2018 11:58:32 -0700 (PDT) X-Original-To: lustre-devel@lists.lustre.org Delivered-To: lustre-devel-lustre.org@pdx1-mailman02.dreamhost.com Received: from smtp3.ccs.ornl.gov (smtp3.ccs.ornl.gov [160.91.203.39]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id B155921F6E1 for ; Sun, 14 Oct 2018 11:58:26 -0700 (PDT) Received: from star.ccs.ornl.gov (star.ccs.ornl.gov [160.91.202.134]) by smtp3.ccs.ornl.gov (Postfix) with ESMTP id 4FA7B2256; Sun, 14 Oct 2018 14:58:21 -0400 (EDT) Received: by star.ccs.ornl.gov (Postfix, from userid 2004) id 4E4672AD; Sun, 14 Oct 2018 14:58:21 -0400 (EDT) From: James Simmons To: Andreas Dilger , Oleg Drokin , NeilBrown Date: Sun, 14 Oct 2018 14:58:06 -0400 Message-Id: <1539543498-29105-17-git-send-email-jsimmons@infradead.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1539543498-29105-1-git-send-email-jsimmons@infradead.org> References: <1539543498-29105-1-git-send-email-jsimmons@infradead.org> Subject: [lustre-devel] [PATCH 16/28] lustre: statahead: missing barrier before wake_up 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: Lai Siyao , Lustre Development List MIME-Version: 1.0 Errors-To: lustre-devel-bounces@lists.lustre.org Sender: "lustre-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Lai Siyao A barrier is missing before wake_up() in ll_statahead_interpret(), which may cause 'ls' hang. Under the right conditions a basic 'ls' can fail. The debug logs show: statahead.c:683:ll_statahead_interpret()) sa_entry software rc -13 statahead.c:1666:ll_statahead()) revalidate statahead software: -11. Obviously statahead failure didn't notify 'ls' process in time. The mi_cbdata can be stale so add a barrier before calling wake_up(). Signed-off-by: Lai Siyao Signed-off-by: Bob Glossman WC-bug-id: https://jira.whamcloud.com/browse/LU-9210 Reviewed-on: https://review.whamcloud.com/27330 Reviewed-by: Nathaniel Clark Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- drivers/staging/lustre/lustre/llite/statahead.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/staging/lustre/lustre/llite/statahead.c b/drivers/staging/lustre/lustre/llite/statahead.c index 1ad308c..0174a4c 100644 --- a/drivers/staging/lustre/lustre/llite/statahead.c +++ b/drivers/staging/lustre/lustre/llite/statahead.c @@ -680,8 +680,14 @@ static int ll_statahead_interpret(struct ptlrpc_request *req, spin_lock(&lli->lli_sa_lock); if (rc) { - if (__sa_make_ready(sai, entry, rc)) + if (__sa_make_ready(sai, entry, rc)) { + /* LU-9210 : Under the right conditions even 'ls' + * can cause the statahead to fail. Using a memory + * barrier resolves this issue. + */ + smp_mb(); wake_up(&sai->sai_waitq); + } } else { int first = 0; entry->se_minfo = minfo;