From patchwork Sun May 26 06:11:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amir Goldstein X-Patchwork-Id: 1105520 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=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="MT5GSLyj"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45BV9l1h69z9sBV for ; Sun, 26 May 2019 16:11:39 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727734AbfEZGLf (ORCPT ); Sun, 26 May 2019 02:11:35 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:43010 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727717AbfEZGLb (ORCPT ); Sun, 26 May 2019 02:11:31 -0400 Received: by mail-wr1-f65.google.com with SMTP id l17so5254510wrm.10; Sat, 25 May 2019 23:11:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=cducFLuU0ir0Q0WPZZBgZj30yxOPz/TPO76rzq4FrUw=; b=MT5GSLyjdkxiLs7sS42XeP4bahm+UMeBohQ/LGy+5ffS9X60wfhc46H/42daPIXCd3 /9GiWSmv9/P0phUzkn3g1ALZ2sdH7qOjNTJgwUc14idInm/sCJlYwFHQkkwqss6RlARo gz4MuAZgVM1D9myZp+Z76KyM2bVsDZYhBs+IjdUUTMO1tw0W5nfbozqNis+qCKVIphHr S6QGsjLyYoEBZ6+joOdwc3UE6pR0dOx1EByE46Dypn4Ab8fqqG7A6X0Qd0Mgm9Zk0Pxk pPLDorIAICPENkLChejLIhUuqER650ZIj0y4/Cn65WGe36cwh6BTwXALKxnnwROpyFCX xoow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=cducFLuU0ir0Q0WPZZBgZj30yxOPz/TPO76rzq4FrUw=; b=ZLf5R0pNkyVfnMiev5xZ+dXEeY8gV/8hYY8n7LKgvd0374fKm+Yl4rm9oTGnfM/egl UNP7Reoc1MKn55oPCgyADIUJgyPw8Epb+VDbpPqK3pDS/b8tdYgqPnMr5XVYd1EZIoxP hlUfq1Gjo4UOA9NjpzgOcGZh1bleAoV8bPGunXNDO/XuJ8YeWv19a3tH7PSU+5Gubb4D ufN63o7q6/9uTFH3+WVAzsM3qVXewsNK9gF2vW7fgrG+EWijtYArZIYx9qiLy6LOBBkO /arWRwlGFLmncZhZoTiHvvV+0CXyrDz+uCAH4IpGXes9YdjW1B0yHpdLq/gTeO+vVBHV fgeg== X-Gm-Message-State: APjAAAUCpprArdTrkLjc0uPA8kvBPBgE9zp3qPRFEk1spR3zh8CuLLfY rAnAUR9rs1Jzi2slT6k0OTI= X-Google-Smtp-Source: APXvYqxAbdy5mvAvbBTCtmh2uFWBEJilLDh3vNpbDyE1F1QGGJU8IaJcsa1VOG5wnc99eBGqOcbWiw== X-Received: by 2002:a5d:534b:: with SMTP id t11mr24310161wrv.297.1558851088914; Sat, 25 May 2019 23:11:28 -0700 (PDT) Received: from localhost.localdomain ([5.102.238.208]) by smtp.gmail.com with ESMTPSA id a124sm5302943wmh.3.2019.05.25.23.11.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 25 May 2019 23:11:28 -0700 (PDT) From: Amir Goldstein To: "Darrick J . Wong" Cc: Dave Chinner , Christoph Hellwig , Olga Kornievskaia , Luis Henriques , Al Viro , linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-api@vger.kernel.org, Dave Chinner Subject: [PATCH v2 9/8] man-pages: copy_file_range updates Date: Sun, 26 May 2019 09:11:00 +0300 Message-Id: <20190526061100.21761-10-amir73il@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190526061100.21761-1-amir73il@gmail.com> References: <20190526061100.21761-1-amir73il@gmail.com> Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Update with all the missing errors the syscall can return, the behaviour the syscall should have w.r.t. to copies within single files, etc. [Amir] Copying beyond EOF returns zero. Signed-off-by: Dave Chinner Signed-off-by: Amir Goldstein --- man2/copy_file_range.2 | 93 ++++++++++++++++++++++++++++++++++-------- 1 file changed, 77 insertions(+), 16 deletions(-) diff --git a/man2/copy_file_range.2 b/man2/copy_file_range.2 index 2438b63c8..fab11f977 100644 --- a/man2/copy_file_range.2 +++ b/man2/copy_file_range.2 @@ -42,9 +42,9 @@ without the additional cost of transferring data from the kernel to user space and then back into the kernel. It copies up to .I len -bytes of data from file descriptor +bytes of data from the source file descriptor .I fd_in -to file descriptor +to target file descriptor .IR fd_out , overwriting any data that exists within the requested range of the target file. .PP @@ -74,6 +74,11 @@ is not changed, but .I off_in is adjusted appropriately. .PP +.I fd_in +and +.I fd_out +can refer to the same file. If they refer to the same file, then the source and +target ranges are not allowed to overlap. .PP The .I flags @@ -84,6 +89,11 @@ Upon successful completion, .BR copy_file_range () will return the number of bytes copied between files. This could be less than the length originally requested. +If the file offset of +.I fd_in +is at or past the end of file, no bytes are copied, and +.BR copy_file_range () +returns zero. .PP On error, .BR copy_file_range () @@ -93,12 +103,16 @@ is set to indicate the error. .SH ERRORS .TP .B EBADF -One or more file descriptors are not valid; or +One or more file descriptors are not valid. +.TP +.B EBADF .I fd_in is not open for reading; or .I fd_out -is not open for writing; or -the +is not open for writing. +.TP +.B EBADF +The .B O_APPEND flag is set for the open file description (see .BR open (2)) @@ -106,17 +120,36 @@ referred to by the file descriptor .IR fd_out . .TP .B EFBIG -An attempt was made to write a file that exceeds the implementation-defined -maximum file size or the process's file size limit, -or to write at a position past the maximum allowed offset. +An attempt was made to write at a position past the maximum file offset the +kernel supports. +.TP +.B EFBIG +An attempt was made to write a range that exceeds the allowed maximum file size. +The maximum file size differs between filesystem implemenations and can be +different to the maximum allowed file offset. +.TP +.B EFBIG +An attempt was made to write beyond the process's file size resource +limit. This may also result in the process receiving a +.I SIGXFSZ +signal. .TP .B EINVAL -Requested range extends beyond the end of the source file; or the +The .I flags argument is not 0. .TP -.B EIO -A low-level I/O error occurred while copying. +.B EINVAL +.I fd_in +and +.I fd_out +refer to the same file and the source and target ranges overlap. +.TP +.B EINVAL +.I fd_in +or +.I fd_out +is not a regular file. .TP .B EISDIR .I fd_in @@ -124,22 +157,50 @@ or .I fd_out refers to a directory. .TP +.B EOVERFLOW +The requested source or destination range is too large to represent in the +specified data types. +.TP +.B EIO +A low-level I/O error occurred while copying. +.TP .B ENOMEM Out of memory. .TP -.B ENOSPC -There is not enough space on the target filesystem to complete the copy. -.TP .B EXDEV The files referred to by .IR file_in " and " file_out -are not on the same mounted filesystem. +are not on the same mounted filesystem (pre Linux 5.3). +.TP +.B ENOSPC +There is not enough space on the target filesystem to complete the copy. +.TP +.B TXTBSY +.I fd_in +or +.I fd_out +refers to an active swap file. +.TP +.B EPERM +.I fd_out +refers to an immutable file. +.TP +.B EACCES +The user does not have write permissions for the destination file. .SH VERSIONS The .BR copy_file_range () system call first appeared in Linux 4.5, but glibc 2.27 provides a user-space emulation when it is not available. .\" https://sourceware.org/git/?p=glibc.git;a=commit;f=posix/unistd.h;h=bad7a0c81f501fbbcc79af9eaa4b8254441c4a1f +.PP +A major rework of the kernel implementation occurred in 5.3. Areas of the API +that weren't clearly defined were clarified and the API bounds are much more +strictly checked than on earlier kernels. Applications should target the +behaviour and requirements of 5.3 kernels. +.PP +First support for cross-filesystem copies was introduced in Linux 5.3. Older +kernels will return -EXDEV when cross-filesystem copies are attempted. .SH CONFORMING TO The .BR copy_file_range () @@ -224,7 +285,7 @@ main(int argc, char **argv) } len \-= ret; - } while (len > 0); + } while (len > 0 && ret > 0); close(fd_in); close(fd_out);