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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29C64C77B7E for ; Thu, 1 Jun 2023 22:29:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233214AbjFAW3f (ORCPT ); Thu, 1 Jun 2023 18:29:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233222AbjFAW3d (ORCPT ); Thu, 1 Jun 2023 18:29:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BF61197 for ; Thu, 1 Jun 2023 15:29:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DDEDB64A91 for ; Thu, 1 Jun 2023 22:29:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40CA9C433D2; Thu, 1 Jun 2023 22:29:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1685658566; bh=rh63Rt9573th05HahU+uUBmyuOLFvKzxRI1dvdkqZ5A=; h=Date:To:From:Subject:From; b=VNBc4HfzP8+j5+560HvZuliWGBRlH6Rr5e2cccAtBnEa+kwNrQyJUepe0hN1hW2Ep A90UVXPXNlBBb6dCWhuIx8bkwIlzbVMk3RC8WhokddOaRmDcRQLlCh/nPu5RqWnCCH mVY527LhbXX/kpf4SjzY/fkTV/3lujYCouPj3PQY= Date: Thu, 01 Jun 2023 15:29:25 -0700 To: mm-commits@vger.kernel.org, xiubli@redhat.com, willy@infradead.org, viro@zeniv.linux.org.uk, tytso@mit.edu, trond.myklebust@hammerspace.com, mszeredi@redhat.com, miklos@szeredi.hu, johannes.thumshirn@wdc.com, jaegeuk@kernel.org, idryomov@gmail.com, hare@suse.de, dlemoal@kernel.org, djwong@kernel.org, chao@kernel.org, brauner@kernel.org, axboe@kernel.dk, anna@kernel.org, agruenba@redhat.com, hch@lst.de, akpm@linux-foundation.org From: Andrew Morton Subject: + fs-factor-out-a-direct_write_fallback-helper.patch added to mm-unstable branch Message-Id: <20230601222926.40CA9C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: fs: factor out a direct_write_fallback helper has been added to the -mm mm-unstable branch. Its filename is fs-factor-out-a-direct_write_fallback-helper.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fs-factor-out-a-direct_write_fallback-helper.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Christoph Hellwig Subject: fs: factor out a direct_write_fallback helper Date: Thu, 1 Jun 2023 16:59:01 +0200 Add a helper dealing with handling the syncing of a buffered write fallback for direct I/O. Link: https://lkml.kernel.org/r/20230601145904.1385409-10-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Reviewed-by: Miklos Szeredi Cc: Al Viro Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Chao Yu Cc: Christian Brauner Cc: "Darrick J. Wong" Cc: Hannes Reinecke Cc: Ilya Dryomov Cc: Jaegeuk Kim Cc: Jens Axboe Cc: Johannes Thumshirn Cc: Matthew Wilcox Cc: Miklos Szeredi Cc: Theodore Ts'o Cc: Trond Myklebust Cc: Xiubo Li Signed-off-by: Andrew Morton --- fs/libfs.c | 41 +++++++++++++++++++++++++ include/linux/fs.h | 2 + mm/filemap.c | 68 ++++++++++--------------------------------- 3 files changed, 59 insertions(+), 52 deletions(-) --- a/fs/libfs.c~fs-factor-out-a-direct_write_fallback-helper +++ a/fs/libfs.c @@ -1613,3 +1613,44 @@ u64 inode_query_iversion(struct inode *i 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); --- a/include/linux/fs.h~fs-factor-out-a-direct_write_fallback-helper +++ a/include/linux/fs.h @@ -2744,6 +2744,8 @@ extern ssize_t __generic_file_write_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); --- a/mm/filemap.c~fs-factor-out-a-direct_write_fallback-helper +++ a/mm/filemap.c @@ -3979,23 +3979,19 @@ ssize_t __generic_file_write_iter(struct { 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; - - err = file_update_time(file); - if (err) - goto out; + ret = file_remove_privs(file); + if (ret) + return ret; + + 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 @@ -4003,45 +3999,13 @@ ssize_t __generic_file_write_iter(struct * 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); _ Patches currently in -mm which might be from hch@lst.de are backing_dev-remove-current-backing_dev_info.patch iomap-update-ki_pos-a-little-later-in-iomap_dio_complete.patch filemap-update-ki_pos-in-generic_perform_write.patch filemap-add-a-kiocb_write_and_wait-helper.patch filemap-add-a-kiocb_invalidate_pages-helper.patch filemap-add-a-kiocb_invalidate_post_direct_write-helper.patch iomap-update-ki_pos-in-iomap_file_buffered_write.patch iomap-use-kiocb_write_and_wait-and-kiocb_invalidate_pages.patch fs-factor-out-a-direct_write_fallback-helper.patch fuse-update-ki_pos-in-fuse_perform_write.patch fuse-drop-redundant-arguments-to-fuse_perform_write.patch fuse-use-direct_write_fallback.patch squashfs-dont-include-buffer_headh.patch