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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 ABCD3C35DEE for ; Thu, 27 Feb 2020 13:53:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8472024656 for ; Thu, 27 Feb 2020 13:53:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811638; bh=eD/DJ1LstZ9eNOd8Ti1BbuQe6wDVPeHT7k72/pE1F6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OoZKhcZfBU7erVOWzansd6KTP9DC+O17EFYHiIISdjser9EzPZolU/oNhOKd/dq1q uPsGAIe4tAHjTlhiu2vhxqQXdIP0QjoJaRdrMmDbCDb+eGfEDKOAOd80ujp5ne57I7 Og//1cLwrL1e/DA0LTJ6cBrKdfsEpPEWnJPGseD0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731796AbgB0Nx5 (ORCPT ); Thu, 27 Feb 2020 08:53:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:53878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731767AbgB0Nxy (ORCPT ); Thu, 27 Feb 2020 08:53:54 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F28D82084E; Thu, 27 Feb 2020 13:53:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811634; bh=eD/DJ1LstZ9eNOd8Ti1BbuQe6wDVPeHT7k72/pE1F6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RoMR+pppLGgukS9T5VovNYWcCETIQKk374fi1vW5gC6WCc0m8h8t+k7+vcUpP8sji +1+Ua4uQNAgp/yGaYS0mXQXsw66QXtr80avzw6/P6Rs/JTxUpGGofyQNcuD82MAs9F cvXnD7peG9eY4I21bAJ944lWqIyr2ixaEriqqQqo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Matthew Bobrowski , Joseph Qi , Ritesh Harjani , Theodore Tso , Sasha Levin Subject: [PATCH 4.14 043/237] ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT Date: Thu, 27 Feb 2020 14:34:17 +0100 Message-Id: <20200227132259.878232093@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132255.285644406@linuxfoundation.org> References: <20200227132255.285644406@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ritesh Harjani [ Upstream commit f629afe3369e9885fd6e9cc7a4f514b6a65cf9e9 ] Apparently our current rwsem code doesn't like doing the trylock, then lock for real scheme. So change our dax read/write methods to just do the trylock for the RWF_NOWAIT case. This seems to fix AIM7 regression in some scalable filesystems upto ~25% in some cases. Claimed in commit 942491c9e6d6 ("xfs: fix AIM7 regression") Reviewed-by: Jan Kara Reviewed-by: Matthew Bobrowski Tested-by: Joseph Qi Signed-off-by: Ritesh Harjani Link: https://lore.kernel.org/r/20191212055557.11151-2-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/file.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 4ede0af9d6fe3..acec134da57df 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -38,9 +38,10 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; - if (!inode_trylock_shared(inode)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock_shared(inode)) return -EAGAIN; + } else { inode_lock_shared(inode); } /* @@ -188,9 +189,10 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; - if (!inode_trylock(inode)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) return -EAGAIN; + } else { inode_lock(inode); } ret = ext4_write_checks(iocb, from); -- 2.20.1