From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S940460AbdAJOBR (ORCPT ); Tue, 10 Jan 2017 09:01:17 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:34768 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750946AbdAJNwR (ORCPT ); Tue, 10 Jan 2017 08:52:17 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , "Darrick J. Wong" , Dave Chinner , Dave Chinner , Christoph Hellwig Subject: [PATCH 4.9 182/206] xfs: always succeed when deduping zero bytes Date: Tue, 10 Jan 2017 14:37:45 +0100 Message-Id: <20170110131511.314044450@linuxfoundation.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170110131502.767555407@linuxfoundation.org> References: <20170110131502.767555407@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Darrick J. Wong" commit fba3e594ef0ad911fa8f559732d588172f212d71 upstream. It turns out that btrfs and xfs had differing interpretations of what to do when the dedupe length is zero. Change xfs to follow btrfs' semantics so that the userland interface is consistent. Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner Cc: Christoph Hellwig Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_reflink.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1345,8 +1345,14 @@ xfs_reflink_remap_range( goto out_unlock; } - if (len == 0) + /* Zero length dedupe exits immediately; reflink goes to EOF. */ + if (len == 0) { + if (is_dedupe) { + ret = 0; + goto out_unlock; + } len = isize - pos_in; + } /* Ensure offsets don't wrap and the input is inside i_size */ if (pos_in + len < pos_in || pos_out + len < pos_out ||