From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cantor2.suse.de ([195.135.220.15]:43682 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754284AbaBFO3W (ORCPT ); Thu, 6 Feb 2014 09:29:22 -0500 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 04304ABB3 for ; Thu, 6 Feb 2014 14:29:22 +0000 (UTC) From: David Disseldorp To: linux-btrfs@vger.kernel.org Cc: David Disseldorp Subject: [PATCH] ioctl: add note regarding CLONE_RANGE(len=0) behaviour Date: Thu, 6 Feb 2014 15:29:18 +0100 Message-Id: <1391696958-4522-1-git-send-email-ddiss@suse.de> Sender: linux-btrfs-owner@vger.kernel.org List-ID: A BTRFS_IOC_CLONE_RANGE request with a src_length value of zero has the effect of cloning all data from src_offset through to end-of-file. Document this behaviour in the header file for those who (like me) incorrectly assume that no data is cloned in such a case. Signed-off-by: David Disseldorp --- ioctl.h | 1 + 1 file changed, 1 insertion(+) diff --git a/ioctl.h b/ioctl.h index a589cd7..f7d435d 100644 --- a/ioctl.h +++ b/ioctl.h @@ -506,6 +506,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code) #define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \ struct btrfs_ioctl_vol_args) +/* With a @src_length of zero, the range from @src_offset->EOF is cloned! */ struct btrfs_ioctl_clone_range_args { __s64 src_fd; __u64 src_offset, src_length; -- 1.8.4.5