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=-8.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 7DB7EC4CECB for ; Thu, 12 Sep 2019 11:03:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5365D20693 for ; Thu, 12 Sep 2019 11:03:52 +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="Vsnv9GpP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731211AbfILLDv (ORCPT ); Thu, 12 Sep 2019 07:03:51 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:33028 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730268AbfILLDv (ORCPT ); Thu, 12 Sep 2019 07:03:51 -0400 Received: by mail-pf1-f195.google.com with SMTP id q10so15792285pfl.0 for ; Thu, 12 Sep 2019 04:03:51 -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:references:mime-version :content-disposition:in-reply-to:user-agent; bh=gWhEv95xTEIL42qPF3+CSeyG/Xs7G/CybwgHcd2mrXY=; b=Vsnv9GpP/UwFIuF1xKQ1ymfWv4uzJy++3sv+5fdk76QqcRzf9lyyN6naP60MS7Bsuo qANymsS6MIzGRxEsVIzIZYhj9h1hwplWnVrxDyN5m5Zwd+0ksXYwlydloFFbK2Mkm3SZ xwTtkUApbqn/nkubInIphQb1goysnPXrkeWScszARjIf4vUHVIJfMPCfbRnEhvCFP6UM QidOAQJgxDipAwRqwINCbG8y4d34iQ+8wD5hVQaz+IQxpxf6Hx/Oqwg5lWUch1vPX8Fs XuSQ1FZIalNZcE+XjZioGEH+X9ZdHIe6WY/3C3sNk49A2uraGYFOtAm2b7H6Wdlv2ieL hvSw== 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:references :mime-version:content-disposition:in-reply-to:user-agent; bh=gWhEv95xTEIL42qPF3+CSeyG/Xs7G/CybwgHcd2mrXY=; b=QhzeGBHqRXNXYgllxwPLvkgCO0GcUaAuqbJ2XkZmP8wIIR2wkfjXt1XIKytCYbVVcC Mlaug1E/0P7m2uSEPuoT5Pqof42n2zzF4byc/Nad+iy206LSUOlDqJeCGnsKJK4mTakI PC/zlU3GGVZ0JMeT0s1nB0sYZEP9XIy5WBu070LkB+bJZPnNlbh3RbdyW/FrZRMPHOaH /GfOfqmx5AMPUAAbEKwPbtDsLQFQ4dGzGPKW/aR/G5STF06OSqO4r2yy+H4+9J/LRb6r +Lb2Z59CIh6s5tXUFukYnP1V/sfOoFEKiGG1yUCGP/H6fla5/clHGvCBq3T0/ItINskp 1uOw== X-Gm-Message-State: APjAAAUSVq1kmXrhhCiNgrkLB/Oh+PWydi8GcMKlrD6TzDBqoz8cCTKN 7w9vFl0bqIZnGUnyOekVaIID X-Google-Smtp-Source: APXvYqykU0mNgWLqAuP8phxMNxNkCBH3W2aeVGPttM6WmZ4Nl3WnKNHLPADJRMDRTPoNGP8s5YETyw== X-Received: by 2002:a63:d64f:: with SMTP id d15mr38390739pgj.345.1568286230822; Thu, 12 Sep 2019 04:03:50 -0700 (PDT) Received: from poseidon.bobrowski.net ([114.78.226.167]) by smtp.gmail.com with ESMTPSA id c125sm31171591pfa.107.2019.09.12.04.03.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Sep 2019 04:03:50 -0700 (PDT) Date: Thu, 12 Sep 2019 21:03:44 +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 1/6] ext4: introduce direct IO read path using iomap infrastructure Message-ID: <532d8deae8e522a27539470457eec6b1a5683127.1568282664.git.mbobrowski@mbobrowski.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This patch introduces a new direct IO read path that makes use of the iomap infrastructure. The new function ext4_dio_read_iter() is responsible for calling into the iomap infrastructure via iomap_dio_rw(). If the inode in question does not pass preliminary checks in ext4_dio_checks(), then we simply fallback to buffered IO and take that path to fulfil the request. It's imperative that we drop the IOCB_DIRECT flag from iocb->ki_flags in order to prevent generic_file_read_iter() from trying to take the direct IO code path again. Signed-off-by: Matthew Bobrowski Reviewed-by: Ritesh Harjani --- fs/ext4/file.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 54 insertions(+), 4 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 70b0438dbc94..e52e3928dc25 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -34,6 +34,53 @@ #include "xattr.h" #include "acl.h" +static bool ext4_dio_checks(struct inode *inode) +{ +#if IS_ENABLED(CONFIG_FS_ENCRYPTION) + if (IS_ENCRYPTED(inode)) + return false; +#endif + if (ext4_should_journal_data(inode)) + return false; + if (ext4_has_inline_data(inode)) + return false; + return true; +} + +static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + ssize_t ret; + struct inode *inode = file_inode(iocb->ki_filp); + + /* + * Get exclusion from truncate and other inode operations. + */ + if (!inode_trylock_shared(inode)) { + if (iocb->ki_flags & IOCB_NOWAIT) + return -EAGAIN; + inode_lock_shared(inode); + } + + if (!ext4_dio_checks(inode)) { + inode_unlock_shared(inode); + /* + * Fallback to buffered IO if the operation being + * performed on the inode is not supported by direct + * IO. The IOCB_DIRECT flag flags needs to be cleared + * here to ensure that the direct IO code path within + * generic_file_read_iter() is not taken again. + */ + iocb->ki_flags &= ~IOCB_DIRECT; + return generic_file_read_iter(iocb, to); + } + + ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL); + inode_unlock_shared(inode); + + file_accessed(iocb->ki_filp); + return ret; +} + #ifdef CONFIG_FS_DAX static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) { @@ -64,16 +111,19 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to) { - if (unlikely(ext4_forced_shutdown(EXT4_SB(file_inode(iocb->ki_filp)->i_sb)))) + struct inode *inode = file_inode(iocb->ki_filp); + + if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) return -EIO; if (!iov_iter_count(to)) return 0; /* skip atime */ -#ifdef CONFIG_FS_DAX - if (IS_DAX(file_inode(iocb->ki_filp))) + if (IS_DAX(inode)) return ext4_dax_read_iter(iocb, to); -#endif + + if (iocb->ki_flags & IOCB_DIRECT) + return ext4_dio_read_iter(iocb, to); return generic_file_read_iter(iocb, to); } -- 2.20.1