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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 35916C4CECB for ; Thu, 12 Sep 2019 11:03:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 081A720693 for ; Thu, 12 Sep 2019 11:03:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=mbobrowski-org.20150623.gappssmtp.com header.i=@mbobrowski-org.20150623.gappssmtp.com header.b="e1ZsZIQK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731343AbfILLDj (ORCPT ); Thu, 12 Sep 2019 07:03:39 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:36456 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731146AbfILLDi (ORCPT ); Thu, 12 Sep 2019 07:03:38 -0400 Received: by mail-pg1-f194.google.com with SMTP id j191so2761091pgd.3 for ; Thu, 12 Sep 2019 04:03:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mbobrowski-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=6TdpHGRMo/9QGFFi43irhTk/FFMkZ5MctGN+Nor7bUo=; b=e1ZsZIQKwY04TZyCyLF3+eKdqL7zUB44U/DjsjtqLdpGeQZpMXkNYhq4tEu53pbWja kcnWDtijf9xsDUsHu2fEyJUp4RtOPkJKcsIBZm+3F+drHu2zZdAYO4AGPgq+5LxcT6/Z Humd2JXqYUlmyA8DTIX9vQLaQR0ZuxIxsDsglIrAO4M/GvgrVlJM+BI3+njZKeOul5ey ZqRMAIvN3JlL4XIYDwYxNdkpR2AiIs5mgbx8EE55odTiXuaUUZT9iUpPdpGuOswppxkM QIgO57DSW59CR4jTS1hYBQzGSKj6VT8tNSk1cgI+NGLIi7+2uLFXLODIwuvGxYGjTAkq VRRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=6TdpHGRMo/9QGFFi43irhTk/FFMkZ5MctGN+Nor7bUo=; b=pyHwJlSbWoFHSQ024/y+N8hbLftng3qzMcYI3WyUa/MV0VtqPO27I19pAiKXEE/NHV ehlda394cMrLGS+WG+KkluTCeoJZ6hJ6nmib4ZGPzQhPMESgmyZWsIdYo2ffnMVfYjHN Ztyeg4N6viv27TynZMenH7c72+Pat6Sy5//HBg9Hy5eha4jjES4vsPI0GEPum57zAwqV v4ysNqRZYPVG0ofXYDTbaMnCn6nT4+MCiEJkOYQTCE8ExndrAtH0EXtHzv+nGQLll3bw eJRQ1RFlYoYc/+vvHDju8HVHfxyWL067hF6u3k7FAn51VB4oGgZdrr0hDYhIq32ImwQ2 KGWQ== X-Gm-Message-State: APjAAAVOBqQKI8OpS3kGTJtNQA12J5hjJElTdlE7WaKIfAHNXieJ1CV8 6GM7ca8pQiGMRt5bLdAW2laM X-Google-Smtp-Source: APXvYqxMi/6AwAWIBbV3Fk+7VAehvArZGxks4tfVfWiG90d8S7WeSaYnEa0sztMwIwxAYvqzUV7e+A== X-Received: by 2002:a63:c246:: with SMTP id l6mr37856485pgg.210.1568286215350; Thu, 12 Sep 2019 04:03:35 -0700 (PDT) Received: from poseidon.bobrowski.net ([114.78.226.167]) by smtp.gmail.com with ESMTPSA id u65sm27618703pfu.104.2019.09.12.04.03.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Sep 2019 04:03:34 -0700 (PDT) Date: Thu, 12 Sep 2019 21:03:28 +1000 From: Matthew Bobrowski To: tytso@mit.edu, jack@suse.cz, adilger.kernel@dilger.ca Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, david@fromorbit.com, hch@infradead.org, darrick.wong@oracle.com Subject: [PATCH v3 0/6] ext4: port direct IO to iomap infrastructure Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org This patch series ports the ext4 direct IO paths to make use of the iomap infrastructure. The legacy buffer_head based direct IO paths have subsequently been removed as they're now no longer in use. The result of this change is that the direct IO implementation is much cleaner and keeps the code isolated from the buffer_head internals. In addition to this, a slight performance boost could be expected while using O_SYNC | O_DIRECT IO. The changes have been tested using xfstests in both DAX and non-DAX modes using various filesystem configurations i.e. 4k, dioread_nolock. Changes since v2: - Simplified ext4_write_checks() by using file_modified() as oppose to calling file_remove_privs() and file_update_time() explicitly. - Other minor cleanups that have been suggested by Ritesh Harjani in the previous round of feedback. In the original patch series, there was a relatively lengthy discussion around the merging of unwritten extents. The buffer_head direct IO implementation made use of inode and end_io flags to track whether an unwritten extent is eligible to be merged, or not. We don't make use of these flags in the new direct IO iomap implementation, effectively making the extent merging checks that make use these flags redundant. However, it appears that even if additional merges and splits are performed, it isn't deemed problematic as such and that's due to the way that the filesystem now accommdates for unexpected extent splits. The only real concern is the potential wasted performance due to the unnecessary merge and split performed under specific workloads. The full discussion that goes through these details starts from here: https://www.spinics.net/lists/linux-ext4/msg67173.html. Thank you to all that took the time to review and provide constructive feedback for previous patch series, highly appreciated. Matthew Bobrowski (6): ext4: introduce direct IO read path using iomap infrastructure ext4: move inode extension/truncate code out from ext4_iomap_end() iomap: split size and error for iomap_dio_rw ->end_io ext4: reorder map.m_flags checks in ext4_iomap_begin() ext4: introduce direct IO write path using iomap infrastructure ext4: cleanup legacy buffer_head direct IO code fs/ext4/ext4.h | 3 - fs/ext4/extents.c | 11 +- fs/ext4/file.c | 364 +++++++++++++++++++++++------ fs/ext4/inode.c | 516 +++++------------------------------------- fs/iomap/direct-io.c | 9 +- fs/xfs/xfs_file.c | 8 +- include/linux/iomap.h | 4 +- 7 files changed, 363 insertions(+), 552 deletions(-) -- 2.20.1