From patchwork Wed May 31 07:50:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13261622 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47EEEC7EE24 for ; Wed, 31 May 2023 07:52:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234942AbjEaHwD (ORCPT ); Wed, 31 May 2023 03:52:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234884AbjEaHvY (ORCPT ); Wed, 31 May 2023 03:51:24 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5FF7E46; Wed, 31 May 2023 00:50:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=11fdSgTG4jIa+lyPH9HFZjOssjJQOFkzGuhPffE88Ak=; b=N1IkSc/F+8A4KQZ69jwKm+YdVJ ttzm96cZrwRIglbmBQ7IM5r/NkpF04kG82W7HAoa2XeT3JqbLH9NHTWBanjy9ttbehUxPmZv1ziAa ZPjwzx263cmBsH2k08HRlZqhWrrJEQTRDLSj81pBtTdaeRZiQwJuIF1V7Pjb70zz1bLEwjIef8fS0 ejj0atwMoeXbA3dxf6snc8QgefUF7DakmT61oqvfsJn+DYJ3h5KFnE4H7KYgfmLDNYjp6DkzRQY0J 4VgxKppjSfcbo3TDcefjJe52TouvoD56hyuShTmjKbP30TJToxprGqjLVwDlsUJmVLEsYAiJvNStV 1fwL7WUA==; Received: from [2001:4bb8:182:6d06:f5c3:53d7:b5aa:b6a7] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1q4Gbc-00GVv5-2z; Wed, 31 May 2023 07:50:53 +0000 From: Christoph Hellwig To: Matthew Wilcox Cc: Jens Axboe , Xiubo Li , Ilya Dryomov , Alexander Viro , Christian Brauner , "Theodore Ts'o" , Jaegeuk Kim , Chao Yu , Miklos Szeredi , Andreas Gruenbacher , "Darrick J. Wong" , Trond Myklebust , Anna Schumaker , Damien Le Moal , Andrew Morton , linux-block@vger.kernel.org, ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 09/12] fs: factor out a direct_write_fallback helper Date: Wed, 31 May 2023 09:50:23 +0200 Message-Id: <20230531075026.480237-10-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230531075026.480237-1-hch@lst.de> References: <20230531075026.480237-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Add a helper dealing with handling the syncing of a buffered write fallback for direct I/O. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Reviewed-by: Miklos Szeredi --- fs/libfs.c | 41 ++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ mm/filemap.c | 66 +++++++++++----------------------------------- 3 files changed, 58 insertions(+), 51 deletions(-) diff --git a/fs/libfs.c b/fs/libfs.c index 89cf614a327158..5b851315eeed03 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1613,3 +1613,44 @@ u64 inode_query_iversion(struct inode *inode) return cur >> I_VERSION_QUERIED_SHIFT; } EXPORT_SYMBOL(inode_query_iversion); + +ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, + ssize_t direct_written, ssize_t buffered_written) +{ + struct address_space *mapping = iocb->ki_filp->f_mapping; + loff_t pos = iocb->ki_pos - buffered_written; + loff_t end = iocb->ki_pos - 1; + int err; + + /* + * If the buffered write fallback returned an error, we want to return + * the number of bytes which were written by direct I/O, or the error + * code if that was zero. + * + * Note that this differs from normal direct-io semantics, which will + * return -EFOO even if some bytes were written. + */ + if (unlikely(buffered_written < 0)) { + if (direct_written) + return direct_written; + return buffered_written; + } + + /* + * We need to ensure that the page cache pages are written to disk and + * invalidated to preserve the expected O_DIRECT semantics. + */ + err = filemap_write_and_wait_range(mapping, pos, end); + if (err < 0) { + /* + * We don't know how much we wrote, so just return the number of + * bytes which were direct-written + */ + if (direct_written) + return direct_written; + return err; + } + invalidate_mapping_pages(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT); + return direct_written + buffered_written; +} +EXPORT_SYMBOL_GPL(direct_write_fallback); diff --git a/include/linux/fs.h b/include/linux/fs.h index 91021b4e1f6f48..6af25137543824 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2738,6 +2738,8 @@ extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *); extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *); extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *); ssize_t generic_perform_write(struct kiocb *, struct iov_iter *); +ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, + ssize_t direct_written, ssize_t buffered_written); ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos, rwf_t flags); diff --git a/mm/filemap.c b/mm/filemap.c index ddb6f8aa86d6ca..137508da5525b6 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -4006,23 +4006,19 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; - struct inode *inode = mapping->host; - ssize_t written = 0; - ssize_t err; - ssize_t status; + struct inode *inode = mapping->host; + ssize_t ret; - err = file_remove_privs(file); - if (err) - goto out; + ret = file_remove_privs(file); + if (ret) + return ret; - err = file_update_time(file); - if (err) - goto out; + ret = file_update_time(file); + if (ret) + return ret; if (iocb->ki_flags & IOCB_DIRECT) { - loff_t pos, endbyte; - - written = generic_file_direct_write(iocb, from); + ret = generic_file_direct_write(iocb, from); /* * If the write stopped short of completing, fall back to * buffered writes. Some filesystems do this for writes to @@ -4030,45 +4026,13 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) * not succeed (even if it did, DAX does not handle dirty * page-cache pages correctly). */ - if (written < 0 || !iov_iter_count(from) || IS_DAX(inode)) - goto out; - - pos = iocb->ki_pos; - status = generic_perform_write(iocb, from); - /* - * If generic_perform_write() returned a synchronous error - * then we want to return the number of bytes which were - * direct-written, or the error code if that was zero. Note - * that this differs from normal direct-io semantics, which - * will return -EFOO even if some bytes were written. - */ - if (unlikely(status < 0)) { - err = status; - goto out; - } - /* - * We need to ensure that the page cache pages are written to - * disk and invalidated to preserve the expected O_DIRECT - * semantics. - */ - endbyte = pos + status - 1; - err = filemap_write_and_wait_range(mapping, pos, endbyte); - if (err == 0) { - written += status; - invalidate_mapping_pages(mapping, - pos >> PAGE_SHIFT, - endbyte >> PAGE_SHIFT); - } else { - /* - * We don't know how much we wrote, so just return - * the number of bytes which were direct-written - */ - } - } else { - written = generic_perform_write(iocb, from); + if (ret < 0 || !iov_iter_count(from) || IS_DAX(inode)) + return ret; + return direct_write_fallback(iocb, from, ret, + generic_perform_write(iocb, from)); } -out: - return written ? written : err; + + return generic_perform_write(iocb, from); } EXPORT_SYMBOL(__generic_file_write_iter);