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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECD1BC433F5 for ; Wed, 24 Nov 2021 12:41:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242995AbhKXMom (ORCPT ); Wed, 24 Nov 2021 07:44:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:41628 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345181AbhKXMlD (ORCPT ); Wed, 24 Nov 2021 07:41:03 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2EC2C6101D; Wed, 24 Nov 2021 12:24:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637756674; bh=P5QL9tMAmbayDCavPSBlnLBqfYjcRV+zx7a+AZNd+2A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rOL+rEI0ZEgCyHNX/zS024NbRzqqxSx7Qwa+DcgFSt/VaHEVn0pKgFVQbe8V2We9i qtpl7fBEEaZsCvdqu54ernNKop/PZ1v+zw/2tf88UuL6IYTbajiIFA2DiFQLLj4nrh GeAB6YgGEbnzBBH0KFPosZaqz2Epw8igDfrLw0TM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Sasha Levin Subject: [PATCH 4.14 165/251] NFS: Fix deadlocks in nfs_scan_commit_list() Date: Wed, 24 Nov 2021 12:56:47 +0100 Message-Id: <20211124115716.004509526@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115710.214900256@linuxfoundation.org> References: <20211124115710.214900256@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Trond Myklebust [ Upstream commit 64a93dbf25d3a1368bb58ddf0f61d0a92d7479e3 ] Partially revert commit 2ce209c42c01 ("NFS: Wait for requests that are locked on the commit list"), since it can lead to deadlocks between commit requests and nfs_join_page_group(). For now we should assume that any locked requests on the commit list are either about to be removed and committed by another task, or the writes they describe are about to be retransmitted. In either case, we should not need to worry. Fixes: 2ce209c42c01 ("NFS: Wait for requests that are locked on the commit list") Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/write.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 767e46c09074b..010733c8bdcd3 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1037,25 +1037,11 @@ nfs_scan_commit_list(struct list_head *src, struct list_head *dst, struct nfs_page *req, *tmp; int ret = 0; -restart: list_for_each_entry_safe(req, tmp, src, wb_list) { kref_get(&req->wb_kref); if (!nfs_lock_request(req)) { - int status; - - /* Prevent deadlock with nfs_lock_and_join_requests */ - if (!list_empty(dst)) { - nfs_release_request(req); - continue; - } - /* Ensure we make progress to prevent livelock */ - mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex); - status = nfs_wait_on_request(req); nfs_release_request(req); - mutex_lock(&NFS_I(cinfo->inode)->commit_mutex); - if (status < 0) - break; - goto restart; + continue; } nfs_request_remove_commit_list(req, cinfo); clear_bit(PG_COMMIT_TO_DS, &req->wb_flags); @@ -1904,6 +1890,7 @@ static int __nfs_commit_inode(struct inode *inode, int how, int may_wait = how & FLUSH_SYNC; int ret, nscan; + how &= ~FLUSH_SYNC; nfs_init_cinfo_from_inode(&cinfo, inode); nfs_commit_begin(cinfo.mds); for (;;) { -- 2.33.0