From patchwork Mon Dec 3 08:34:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Chinner X-Patchwork-Id: 1006696 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=fromorbit.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 437dZt107xz9s55 for ; Mon, 3 Dec 2018 19:34:30 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725918AbeLCIe3 (ORCPT ); Mon, 3 Dec 2018 03:34:29 -0500 Received: from ipmailnode02.adl6.internode.on.net ([150.101.137.148]:36689 "EHLO ipmailnode02.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725891AbeLCIe2 (ORCPT ); Mon, 3 Dec 2018 03:34:28 -0500 Received: from ppp59-167-129-252.static.internode.on.net (HELO dastard) ([59.167.129.252]) by ipmail02.adl6.internode.on.net with ESMTP; 03 Dec 2018 19:04:19 +1030 Received: from discord.disaster.area ([192.168.1.111]) by dastard with esmtp (Exim 4.80) (envelope-from ) id 1gTjgI-0003PS-VI; Mon, 03 Dec 2018 19:34:19 +1100 Received: from dave by discord.disaster.area with local (Exim 4.91) (envelope-from ) id 1gTjgI-00005x-UG; Mon, 03 Dec 2018 19:34:18 +1100 From: Dave Chinner To: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org Cc: olga.kornievskaia@gmail.com, linux-nfs@vger.kernel.org, linux-unionfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org Subject: [PATCH 02/11] vfs: introduce generic_copy_file_range() Date: Mon, 3 Dec 2018 19:34:07 +1100 Message-Id: <20181203083416.28978-3-david@fromorbit.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181203083416.28978-1-david@fromorbit.com> References: <20181203083416.28978-1-david@fromorbit.com> MIME-Version: 1.0 Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org From: Dave Chinner Right now if vfs_copy_file_range() does not use any offload mechanism, it falls back to calling do_splice_direct(). This fails to do basic sanity checks on the files being copied. Before we start adding this necessarily functionality to the fallback path, separate it out into generic_copy_file_range(). generic_copy_file_range() has the same prototype as ->copy_file_range() so that filesystems can use it in their custom ->copy_file_range() method if they so choose. Signed-off-by: Dave Chinner Reviewed-by: Amir Goldstein Reviewed-by: Christoph Hellwig --- fs/read_write.c | 35 ++++++++++++++++++++++++++++++++--- include/linux/fs.h | 3 +++ 2 files changed, 35 insertions(+), 3 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 09d1816cf3cf..50114694c98b 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1540,6 +1540,36 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, } #endif +/** + * generic_copy_file_range - copy data between two files + * @file_in: file structure to read from + * @pos_in: file offset to read from + * @file_out: file structure to write data to + * @pos_out: file offset to write data to + * @len: amount of data to copy + * @flags: copy flags + * + * This is a generic filesystem helper to copy data from one file to another. + * It has no constraints on the source or destination file owners - the files + * can belong to different superblocks and different filesystem types. Short + * copies are allowed. + * + * This should be called from the @file_out filesystem, as per the + * ->copy_file_range() method. + * + * Returns the number of bytes copied or a negative error indicating the + * failure. + */ + +ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t len, unsigned int flags) +{ + return do_splice_direct(file_in, &pos_in, file_out, &pos_out, + len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); +} +EXPORT_SYMBOL(generic_copy_file_range); + /* * copy_file_range() differs from regular file read and write in that it * specifically allows return partial success. When it does so is up to @@ -1611,9 +1641,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, goto done; } - ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, - len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); - + ret = generic_copy_file_range(file_in, &pos_in, file_out, &pos_out, + len, flags); done: if (ret > 0) { fsnotify_access(file_in); diff --git a/include/linux/fs.h b/include/linux/fs.h index c95c0807471f..a4478764cf63 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1874,6 +1874,9 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, unsigned long, loff_t *, rwf_t); extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, loff_t, size_t, unsigned int); +extern ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t len, unsigned int flags); extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t *count,