Return-Path: Received: from nov-007-i608.relay.mailchannels.net ([46.232.183.162]:56484 "EHLO nov-007-i608.relay.mailchannels.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750907AbdI2MHx (ORCPT ); Fri, 29 Sep 2017 08:07:53 -0400 From: =?UTF-8?q?J=C3=BCrg=20Billeter?= To: Al Viro Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?J=C3=BCrg=20Billeter?= Subject: [RESEND PATCH] fs: add RWF_APPEND Date: Fri, 29 Sep 2017 14:07:17 +0200 Message-Id: <20170929120717.47515-1-j@bitron.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-fsdevel-owner@vger.kernel.org List-ID: This is the per-I/O equivalent of O_APPEND to support atomic append operations on any open file. If a file is opened with O_APPEND, pwrite() ignores the offset and always appends data to the end of the file. RWF_APPEND enables atomic append and pwrite() with offset on a single file descriptor. Signed-off-by: Jürg Billeter --- include/linux/fs.h | 2 ++ include/uapi/linux/fs.h | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 339e73742e73..fee24eae7523 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3204,6 +3204,8 @@ static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags) ki->ki_flags |= IOCB_DSYNC; if (flags & RWF_SYNC) ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC); + if (flags & RWF_APPEND) + ki->ki_flags |= IOCB_APPEND; return 0; } diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 56235dddea7d..ac145430bcd8 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -376,7 +376,11 @@ typedef int __bitwise __kernel_rwf_t; /* per-IO, return -EAGAIN if operation would block */ #define RWF_NOWAIT ((__force __kernel_rwf_t)0x00000008) +/* per-IO O_APPEND */ +#define RWF_APPEND ((__force __kernel_rwf_t)0x00000010) + /* mask of flags supported by the kernel */ -#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT) +#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ + RWF_APPEND) #endif /* _UAPI_LINUX_FS_H */ -- 2.14.1