From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id 447766B026F for ; Wed, 17 Oct 2018 18:44:41 -0400 (EDT) Received: by mail-pf1-f200.google.com with SMTP id h76-v6so28297987pfd.10 for ; Wed, 17 Oct 2018 15:44:41 -0700 (PDT) Received: from userp2120.oracle.com (userp2120.oracle.com. [156.151.31.85]) by mx.google.com with ESMTPS id c1-v6si19125447pld.107.2018.10.17.15.44.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 17 Oct 2018 15:44:40 -0700 (PDT) Subject: [PATCH 03/29] vfs: exit early from zero length remap operations From: "Darrick J. Wong" Date: Wed, 17 Oct 2018 15:44:36 -0700 Message-ID: <153981627600.5568.16857314567554014035.stgit@magnolia> In-Reply-To: <153981625504.5568.2708520119290577378.stgit@magnolia> References: <153981625504.5568.2708520119290577378.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: david@fromorbit.com, darrick.wong@oracle.com Cc: sandeen@redhat.com, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , ocfs2-devel@oss.oracle.com From: Darrick J. Wong If a remap caller asks us to remap to the source file's EOF and the source file length leaves us with a zero byte request, exit early. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/read_write.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/read_write.c b/fs/read_write.c index d6e8e242a15f..2456da3f8a41 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1748,6 +1748,8 @@ int vfs_clone_file_prep(struct file *file_in, loff_t pos_in, if (pos_in > isize) return -EINVAL; *len = isize - pos_in; + if (*len == 0) + return 0; } /* Check that we don't violate system file offset limits. */