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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 5336EC33CAF for ; Thu, 16 Jan 2020 23:46:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D80D2072B for ; Thu, 16 Jan 2020 23:46:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579218398; bh=JSuBphsjuh0+PpEiMvHb+bCx5t9x0cjW3CLELLPZeHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mXvRdLpLEHIVO3wH9Zg8umWa0gEP8E31668eosFLeCxqNaqgvC+QyOIWjrxuWbvkR aB0fxguzetLUgdrPAFwEiJ5M8qu5Ol8u/Y5DemgDp5PrL6IdMVhOAyY+bvuW+3fnX6 f/DcwdkdHYEU9Eq0JX3BssAUkrxGgNFjPgh+n80E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390856AbgAPXVr (ORCPT ); Thu, 16 Jan 2020 18:21:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:49294 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388978AbgAPXVq (ORCPT ); Thu, 16 Jan 2020 18:21:46 -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 6143420748; Thu, 16 Jan 2020 23:21:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579216905; bh=JSuBphsjuh0+PpEiMvHb+bCx5t9x0cjW3CLELLPZeHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b4kQJbPuUkGdH9MflN/Y+AaeNB6Yhw8GqhrgOhC/RsYmdabTzk+Nx6I5O/c0AxVR5 OGeiE5po1Ib/UF1E5/Xlr1bmGqpVtxjjndn3V6GWtC3g4zXllfFHHRrEhZWLO0KBf5 P+NrBl1RtT7AVWiTvj2Tngn+e8RVI1b6iRSzrc4Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Goldwyn Rodrigues , David Sterba Subject: [PATCH 5.4 052/203] btrfs: simplify inode locking for RWF_NOWAIT Date: Fri, 17 Jan 2020 00:16:09 +0100 Message-Id: <20200116231748.526335217@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200116231745.218684830@linuxfoundation.org> References: <20200116231745.218684830@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Goldwyn Rodrigues commit 9cf35f673583ccc9f3e2507498b3079d56614ad3 upstream. This is similar to 942491c9e6d6 ("xfs: fix AIM7 regression"). Apparently our current rwsem code doesn't like doing the trylock, then lock for real scheme. This causes extra contention on the lock and can be measured eg. by AIM7 benchmark. So change our read/write methods to just do the trylock for the RWF_NOWAIT case. Fixes: edf064e7c6fe ("btrfs: nowait aio support") Signed-off-by: Goldwyn Rodrigues Reviewed-by: David Sterba [ update changelog ] Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/file.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1903,9 +1903,10 @@ static ssize_t btrfs_file_write_iter(str (iocb->ki_flags & IOCB_NOWAIT)) return -EOPNOTSUPP; - 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); }