From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:35278 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761867AbcINMn6 (ORCPT ); Wed, 14 Sep 2016 08:43:58 -0400 From: Amir Goldstein To: Miklos Szeredi , Dave Chinner , linux-unionfs@vger.kernel.org Cc: Christoph Hellwig , linux-xfs@vger.kernel.org, "Darrick J . Wong" , linux-fsdevel@vger.kernel.org Subject: [PATCH v3 3/4] vfs: allow vfs_copy_file_range() across file systems Date: Wed, 14 Sep 2016 15:43:13 +0300 Message-Id: <1473856994-27463-4-git-send-email-amir73il@gmail.com> In-Reply-To: <1473856994-27463-1-git-send-email-amir73il@gmail.com> References: <1473856994-27463-1-git-send-email-amir73il@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: copy_file_range syscall returns -EXDEV if src and dest file are not on the same file system. The vfs_copy_file_range() helper, however, knows how to copy across file systems with do_splice_direct(). Move the enforcement of same file system from the vfs helper to the syscall code. A following patch is going to use the vfs_copy_file_range() helper in overlayfs to copy up between lower and upper not on the same file system. Signed-off-by: Amir Goldstein --- fs/read_write.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 9dc6e52..6975fe8 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1502,10 +1502,6 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, (file_out->f_flags & O_APPEND)) return -EBADF; - /* this could be relaxed once a method supports cross-fs copies */ - if (inode_in->i_sb != inode_out->i_sb) - return -EXDEV; - if (len == 0) return 0; @@ -1514,7 +1510,9 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, return ret; ret = -EOPNOTSUPP; - if (file_out->f_op->copy_file_range) + /* copy_file_range() method does not support cross-fs copies */ + if (inode_in->i_sb == inode_out->i_sb && + file_out->f_op->copy_file_range) ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, len, flags); if (ret == -EOPNOTSUPP) @@ -1569,6 +1567,14 @@ SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in, pos_out = f_out.file->f_pos; } + /* + * vfs_copy_file_range() can do cross-fs copy, but we want to + * fulfill the guaranty to userland that copy_file_range syscall + * does not allow cross-fs copy + */ + if (file_inode(f_in.file)->i_sb != file_inode(f_out.file)->i_sb) + return -EXDEV; + ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len, flags); if (ret > 0) { -- 2.7.4