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=-11.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 A7609C4363D for ; Tue, 22 Sep 2020 14:52:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68E812395C for ; Tue, 22 Sep 2020 14:52:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=toxicpanda-com.20150623.gappssmtp.com header.i=@toxicpanda-com.20150623.gappssmtp.com header.b="R/YjV4Uw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726645AbgIVOwR (ORCPT ); Tue, 22 Sep 2020 10:52:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726625AbgIVOwR (ORCPT ); Tue, 22 Sep 2020 10:52:17 -0400 Received: from mail-qk1-x742.google.com (mail-qk1-x742.google.com [IPv6:2607:f8b0:4864:20::742]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EA40C061755 for ; Tue, 22 Sep 2020 07:52:17 -0700 (PDT) Received: by mail-qk1-x742.google.com with SMTP id d20so19295856qka.5 for ; Tue, 22 Sep 2020 07:52:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toxicpanda-com.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=dF1fa23J+l+HEWIXsoK1ROlWlXhWeKk0bxWwAqVjy6A=; b=R/YjV4UwaRJaRG9MQlKAYtN1BOWc8h82b6sGyauvHvepfQsfJzCmVK9FhxF3nnsJ2F cEBRu7HaKjfHjjWrxaXpf0ud6Zzm/krjFOmgV65w+fTPAtPLXuFbYTJWoYtO5uXFTcxP 1QPSjVoI3Aosl0SzyEAWjTJh1fC+CMsOVJho9mFPoFpNYp2UDJGLxdjbjgOxv4n5PNuz H7fAMMBoF2x0h/wfJWeHTRBl4d9KfVU2YKGVgdMU5ze2Esklk9DHAQkqadozEp+g9HXo 1SZ5Dv+MRAVYL/ge1w7bR31LLCumyh9OlxKJ5P/bVJ1k9h6lzEVq+7QW4PvjRz7zYTk8 c1ng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=dF1fa23J+l+HEWIXsoK1ROlWlXhWeKk0bxWwAqVjy6A=; b=BUEg7FCFRUccMjovc+f0aUzspiEVBrx6JlRVJ74QsnrVipkkXk5KFvwdrpu+Zs8YyN Rr15GWFvy5bRjchLFRmnHj/MnaXycWUnj8uACpC5H0JC2VaTfEd4/9JBX/mdL41BwLxp gh24L/dGFN1HSTjvYZupdwBS2WzGiBjB53RcXUjy8CHowsTv0lkfa5o01RsMcTL+GMfb 3eq8JVyrUMgub3izjIjdYxYRF4BKxd3Iu3xFkhB+046pvlG+3nnVA1uhVuGvW5oOiEKx qyzXKtEfr6HJI3tEi+m4zivGhndHdHu0NbW4Ywi0XBxK67N2HPIybwq0tDKFS/izSNUP M8iw== X-Gm-Message-State: AOAM533TvOagnn3W4UWqRX/TN4oZccjtJZQ8SM10sEsk7qd+0ECH9VNf e/E4KbtZnuHqzGqrvU6+1hcsPQ== X-Google-Smtp-Source: ABdhPJxasZxfhJZ5H4uf8BgLFKo+hiKwBWwEWJEVZFgSQMLbqae8mXbxm2At9NC2QyAm2exLoabS9g== X-Received: by 2002:a37:62c4:: with SMTP id w187mr5124409qkb.102.1600786336392; Tue, 22 Sep 2020 07:52:16 -0700 (PDT) Received: from [192.168.1.45] (cpe-174-109-172-136.nc.res.rr.com. [174.109.172.136]) by smtp.gmail.com with ESMTPSA id 205sm11386504qki.118.2020.09.22.07.52.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Sep 2020 07:52:15 -0700 (PDT) Subject: Re: [PATCH 11/15] btrfs: Use inode_lock_shared() for direct writes within EOF To: Goldwyn Rodrigues , linux-fsdevel@vger.kernel.org Cc: linux-btrfs@vger.kernel.org, david@fromorbit.com, hch@lst.de, johannes.thumshirn@wdc.com, dsterba@suse.com, darrick.wong@oracle.com, Goldwyn Rodrigues References: <20200921144353.31319-1-rgoldwyn@suse.de> <20200921144353.31319-12-rgoldwyn@suse.de> From: Josef Bacik Message-ID: Date: Tue, 22 Sep 2020 10:52:14 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.2.2 MIME-Version: 1.0 In-Reply-To: <20200921144353.31319-12-rgoldwyn@suse.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 9/21/20 10:43 AM, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues > > Direct writes within EOF are safe to be performed with inode shared lock > to improve parallelization with other direct writes or reads because EOF > is not changed and there is no race with truncate(). > > Direct reads are already performed under shared inode lock. > > This patch is precursor to removing btrfs_inode->dio_sem. > > Signed-off-by: Goldwyn Rodrigues > --- > fs/btrfs/file.c | 33 +++++++++++++++++++++------------ > 1 file changed, 21 insertions(+), 12 deletions(-) > > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index d9c3be19d7b3..50092d24eee2 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -1977,7 +1977,6 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from) > struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > loff_t pos; > ssize_t written = 0; > - bool relock = false; > ssize_t written_buffered; > loff_t endbyte; > int err; > @@ -1986,6 +1985,15 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from) > if (iocb->ki_flags & IOCB_NOWAIT) > ilock_flags |= BTRFS_ILOCK_TRY; > > + /* > + * If the write DIO within EOF, use a shared lock > + */ > + if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode)) > + ilock_flags |= BTRFS_ILOCK_SHARED; > + else if (iocb->ki_flags & IOCB_NOWAIT) > + return -EAGAIN; > + > +relock: Huh? Why are you making it so EOF extending NOWAIT writes now fail? We are still using ILOCK_TRY here, so we may still not block, am I missing something? Thanks, Josef