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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 66D3CC2BA83 for ; Fri, 14 Feb 2020 17:46:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 444AB206D7 for ; Fri, 14 Feb 2020 17:46:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581702385; bh=MkrSzaUpyiXGWZsDILQOUpHYbqHimewf164Sb99xzcI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=e9E9sx2VfX2yM/cS893kmhh39Y2QA2+bO19Vmooc6cho0TMXVo26ziW2pKms8/WRa nvm5pq+9JqV6bKeX8qO3bjFxtmiELo8+9LPx12FVBbI11U2iJ2meGsi7SHRNFWluWV nk5wFsgm/+FjRKQzFwWZ3fdiLopqawMs7qfI29oE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389577AbgBNRqY (ORCPT ); Fri, 14 Feb 2020 12:46:24 -0500 Received: from mail.kernel.org ([198.145.29.99]:48742 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389347AbgBNQC0 (ORCPT ); Fri, 14 Feb 2020 11:02:26 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 17BE1206CC; Fri, 14 Feb 2020 16:02:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696146; bh=MkrSzaUpyiXGWZsDILQOUpHYbqHimewf164Sb99xzcI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ab8ZJ8WrZ5zWSksCifvpH7fuJ2WhEcRvv16/soVuXlnKKlWgc1tpHoyBFFs231e41 gt+OzOlKvAw+HvjIqb1qfrM7cHKX2re+xosQjDiqjZoqxUB82+ii96V6nPC1BUDlns inEQfBlHUj6ghDlsq1O4IddpbConUognLMxocZeI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ritesh Harjani , Jan Kara , Matthew Bobrowski , Joseph Qi , Theodore Ts'o , Sasha Levin , linux-ext4@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 026/459] ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT Date: Fri, 14 Feb 2020 10:54:36 -0500 Message-Id: <20200214160149.11681-26-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214160149.11681-1-sashal@kernel.org> References: <20200214160149.11681-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 8d2bbcc2d8133..fd7ce3573a00a 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -40,9 +40,10 @@ 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); } /* @@ -190,9 +191,10 @@ 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