From patchwork Tue Nov 5 12:01:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Bobrowski X-Patchwork-Id: 11227597 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 14FBB1515 for ; Tue, 5 Nov 2019 12:01:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE8D620650 for ; Tue, 5 Nov 2019 12:01:45 +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="CQTh26qn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730876AbfKEMBp (ORCPT ); Tue, 5 Nov 2019 07:01:45 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:46195 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730848AbfKEMBo (ORCPT ); Tue, 5 Nov 2019 07:01:44 -0500 Received: by mail-pg1-f196.google.com with SMTP id f19so13965133pgn.13 for ; Tue, 05 Nov 2019 04:01:44 -0800 (PST) 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=6LibSywqRXYWNf37STd+dCRG3O5Iq29JKhK3bKCXC1M=; b=CQTh26qnHLvJp4R7YJ7HUoMMH8QKakW5Bs+bEAqxTf+TrjmjvjW9wGx8vSaSMKPuRE eytfZ4TXZd6u6sCpAXNJobbqFbfb2TtQWdc6ZoeJhs8VgOAwC5IRbHaQtTy41UipWKEy z864eG35bZh2hyRIyas1BtKz9LPOuGmZS2nCPCDCa0yG9aEJE8hExpLU9OKmIniZMOdc yW9Xk9Ymvh2H1+40Kk+6hg44MIX3Z57ZNV8rUR0PJhW78s0F/5SGTpTjg5wswrzZDCtN JMwlwBd00RUztptucvamfBcpZmflHE4IO5l3vFmUmJip3rd5TO1DbmhNsMo3Od9FtchE f3Ew== 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=6LibSywqRXYWNf37STd+dCRG3O5Iq29JKhK3bKCXC1M=; b=q55b6aDxCzEaxIVRniqku9jd7PhdjqGp+X/fUFKzj26q+rP5kXA//XkrW3zUSBt6Zh UjmtDxlLg8dCmh4F0BWDY4sKlLToRI6/YSrzSd3wzW6bGBVZUw7JopidNhigb3omwIRW xo9QL7c841oqXdFnt1i7naxiVNFEcqe3U9LM+VY4ZfDL+m6XQYHjurX189MuH3evPoPg IfTiQnr2HFPgv0lm2D7e9KR5fthvYocA3egJeFYsYzBWSgviw+kJJnddMc+SNAxX2sG2 yukmu4ZkbN3xGUpLhL/DrnyXsPJ+W8XTH7RQsDxNJKaSOt7/4I6Uk0jRgHeOnjI0S27C Z+KA== X-Gm-Message-State: APjAAAXdgskAtiiAvCn2yhL1vxwTfHitL0tEsbSzs5Yz0iFsYWeDZL8k wDsIJ+PMgMuxxbVw4oFm+f3b X-Google-Smtp-Source: APXvYqxGgRwW6wQeS06JUD8OJFOjC9nZ0rdGXWb/h+t0ik9/XB+YjEWTAK65t+EWoZGOPI8KAINd1Q== X-Received: by 2002:a17:90a:9741:: with SMTP id i1mr6282771pjw.2.1572955303619; Tue, 05 Nov 2019 04:01:43 -0800 (PST) Received: from poseidon.bobrowski.net ([114.78.226.167]) by smtp.gmail.com with ESMTPSA id f189sm28845329pgc.94.2019.11.05.04.01.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Nov 2019 04:01:42 -0800 (PST) Date: Tue, 5 Nov 2019 23:01:37 +1100 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, riteshh@linux.ibm.com Subject: [PATCH v7 07/11] ext4: introduce direct I/O read using iomap infrastructure Message-ID: References: MIME-Version: 1.0 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 I/O read path which makes use of the iomap infrastructure. The new function ext4_do_read_iter() is responsible for calling into the iomap infrastructure via iomap_dio_rw(). If the read operation performed on the inode is not supported, which is checked via ext4_dio_supported(), then we simply fallback and complete the I/O using buffered I/O. Existing direct I/O read code path has been removed, as it is now redundant. Signed-off-by: Matthew Bobrowski Reviewed-by: Jan Kara Reviewed-by: Ritesh Harjani --- fs/ext4/file.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++-- fs/ext4/inode.c | 38 +--------------------------------- 2 files changed, 54 insertions(+), 39 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index ab75aee3e687..440f4c6ba4ee 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -34,6 +34,52 @@ #include "xattr.h" #include "acl.h" +static bool ext4_dio_supported(struct inode *inode) +{ + if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode)) + return false; + if (fsverity_active(inode)) + return false; + 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); + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock_shared(inode)) + return -EAGAIN; + } else { + inode_lock_shared(inode); + } + + if (!ext4_dio_supported(inode)) { + inode_unlock_shared(inode); + /* + * Fallback to buffered I/O if the operation being performed on + * the inode is not supported by direct I/O. The IOCB_DIRECT + * flag needs to be cleared here in order to ensure that the + * direct I/O path within generic_file_read_iter() is not + * taken. + */ + iocb->ki_flags &= ~IOCB_DIRECT; + return generic_file_read_iter(iocb, to); + } + + ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, + is_sync_kiocb(iocb)); + 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 +110,21 @@ 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); } diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index b5ba6767b276..9bd80df6b856 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -863,9 +863,6 @@ int ext4_dio_get_block(struct inode *inode, sector_t iblock, { /* We don't expect handle for direct IO */ WARN_ON_ONCE(ext4_journal_current_handle()); - - if (!create) - return _ext4_get_block(inode, iblock, bh, 0); return ext4_get_block_trans(inode, iblock, bh, EXT4_GET_BLOCKS_CREATE); } @@ -3916,36 +3913,6 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) return ret; } -static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter) -{ - struct address_space *mapping = iocb->ki_filp->f_mapping; - struct inode *inode = mapping->host; - size_t count = iov_iter_count(iter); - ssize_t ret; - - /* - * Shared inode_lock is enough for us - it protects against concurrent - * writes & truncates and since we take care of writing back page cache, - * we are protected against page writeback as well. - */ - if (iocb->ki_flags & IOCB_NOWAIT) { - if (!inode_trylock_shared(inode)) - return -EAGAIN; - } else { - inode_lock_shared(inode); - } - - ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, - iocb->ki_pos + count - 1); - if (ret) - goto out_unlock; - ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, - iter, ext4_dio_get_block, NULL, NULL, 0); -out_unlock: - inode_unlock_shared(inode); - return ret; -} - static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter) { struct file *file = iocb->ki_filp; @@ -3972,10 +3939,7 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter) return 0; trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter)); - if (iov_iter_rw(iter) == READ) - ret = ext4_direct_IO_read(iocb, iter); - else - ret = ext4_direct_IO_write(iocb, iter); + ret = ext4_direct_IO_write(iocb, iter); trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret); return ret; }