From patchwork Thu Sep 16 15:57:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 513763 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 7C2A6C4332F for ; Thu, 16 Sep 2021 17:15:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61EAE60F25 for ; Thu, 16 Sep 2021 17:15:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344123AbhIPRQs (ORCPT ); Thu, 16 Sep 2021 13:16:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:39804 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350351AbhIPRN4 (ORCPT ); Thu, 16 Sep 2021 13:13:56 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A6F0F61B5D; Thu, 16 Sep 2021 16:38:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631810336; bh=nO4fqyB/6RvF5UPCubhhgOtrIynrJ98N1KVOwT5/MZo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=genCACjUSFgm0CSW/9YcevPwexCqybQKfDWYiYsaQAsTWRvIlwtzq1e9fYBHvgLWg KQpVDjle89InXlA16d7+8Xg4Sm7XQtKbcogXzGEPmZkbdBadyKg0VyuDNG942rStxe QfaVR1rcm6VXSBLhvJ5vhJEOCe35bRCJ8dveX03Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Anna Schumaker , Sasha Levin Subject: [PATCH 5.14 104/432] NFSv4/pNFS: Fix a layoutget livelock loop Date: Thu, 16 Sep 2021 17:57:33 +0200 Message-Id: <20210916155814.299415181@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210916155810.813340753@linuxfoundation.org> References: <20210916155810.813340753@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Trond Myklebust [ Upstream commit e20772cbdf463c12088837e5a08bde1b876bfd25 ] If NFS_LAYOUT_RETURN_REQUESTED is set, but there is no value set for the layout plh_return_seq, we can end up in a livelock loop in which every layout segment retrieved by a new call to layoutget is immediately invalidated by pnfs_layout_need_return(). To get around this, we should just set plh_return_seq to the current value of the layout stateid's seqid. Fixes: d474f96104bd ("NFS: Don't return layout segments that are in use") Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- fs/nfs/pnfs.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index ef14ea0b6ab8..da5cacad6979 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -347,11 +347,15 @@ pnfs_set_plh_return_info(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode, iomode = IOMODE_ANY; lo->plh_return_iomode = iomode; set_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags); - if (seq != 0) { - WARN_ON_ONCE(lo->plh_return_seq != 0 && lo->plh_return_seq != seq); + /* + * We must set lo->plh_return_seq to avoid livelocks with + * pnfs_layout_need_return() + */ + if (seq == 0) + seq = be32_to_cpu(lo->plh_stateid.seqid); + if (!lo->plh_return_seq || pnfs_seqid_is_newer(seq, lo->plh_return_seq)) lo->plh_return_seq = seq; - pnfs_barrier_update(lo, seq); - } + pnfs_barrier_update(lo, seq); } static void