From patchwork Fri Mar 24 15:00:57 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 9643035 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 49B196020B for ; Fri, 24 Mar 2017 15:09:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3C91F25F31 for ; Fri, 24 Mar 2017 15:09:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 315C922376; Fri, 24 Mar 2017 15:09:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C54D722376 for ; Fri, 24 Mar 2017 15:09:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756692AbdCXPJf (ORCPT ); Fri, 24 Mar 2017 11:09:35 -0400 Received: from mx2.mailbox.org ([80.241.60.215]:50980 "EHLO mx2.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751701AbdCXPJd (ORCPT ); Fri, 24 Mar 2017 11:09:33 -0400 X-Greylist: delayed 507 seconds by postgrey-1.27 at vger.kernel.org; Fri, 24 Mar 2017 11:09:33 EDT Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx2.mailbox.org (Postfix) with ESMTPS id 474AB44610; Fri, 24 Mar 2017 16:01:04 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp1.mailbox.org ([80.241.60.240]) by spamfilter01.heinlein-hosting.de (spamfilter01.heinlein-hosting.de [80.241.56.115]) (amavisd-new, port 10030) with ESMTP id 6cVUwNaP9sOw; Fri, 24 Mar 2017 16:00:59 +0100 (CET) From: Christian Brauner To: linux-btrfs@vger.kernel.org Cc: Christian Brauner Subject: [PATCH] btrfs-progs: fix btrfs send & receive with -e flag Date: Fri, 24 Mar 2017 16:00:57 +0100 Message-Id: <20170324150057.1752-1-christian.brauner@ubuntu.com> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The old check here tried to ensure that empty streams are not considered valid. The old check however, will always fail when only one run through the while(1) loop is needed and honor_end_cmd is set. So this: btrfs send /some/subvol | btrfs receive -e /some/ will consistently fail because -e causes honor_cmd_to be set and btrfs_read_and_process_send_stream() to correctly return 1. So the command will be successful but btrfs receive will error out because the send - receive concluded in one run through the while(1) loop. If we want to exclude empty streams we need a way to tell the difference between btrfs_read_and_process_send_stream() returning 1 because read_buf() did not detect any data and read_and_process_cmd() returning 1 because honor_end_cmd was set. Without introducing too many changes the best way to me seems to have btrfs_read_and_process_send_stream() return -ENODATA in the first case. The rest stays the same. We can then check for -ENODATA in do_receive() and report a proper error in this case. This should also be backwards compatible to previous versions of btrfs receive. They will fail on empty streams because a negative value is returned. The only thing that they will lack is a nice error message. Signed-off-by: Christian Brauner --- cmds-receive.c | 13 +++++-------- send-stream.c | 2 +- 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/cmds-receive.c b/cmds-receive.c index 6cf22637..b59f00e4 100644 --- a/cmds-receive.c +++ b/cmds-receive.c @@ -1091,7 +1091,6 @@ static int do_receive(struct btrfs_receive *rctx, const char *tomnt, char *dest_dir_full_path; char root_subvol_path[PATH_MAX]; int end = 0; - int count; dest_dir_full_path = realpath(tomnt, NULL); if (!dest_dir_full_path) { @@ -1186,7 +1185,6 @@ static int do_receive(struct btrfs_receive *rctx, const char *tomnt, if (ret < 0) goto out; - count = 0; while (!end) { if (rctx->cached_capabilities_len) { if (g_verbose >= 3) @@ -1200,16 +1198,15 @@ static int do_receive(struct btrfs_receive *rctx, const char *tomnt, rctx, rctx->honor_end_cmd, max_errors); - if (ret < 0) - goto out; - /* Empty stream is invalid */ - if (ret && count == 0) { + if (ret < 0 && ret == -ENODATA) { + /* Empty stream is invalid */ error("empty stream is not considered valid"); ret = -EINVAL; goto out; + } else if (ret < 0) { + goto out; } - count++; - if (ret) + if (ret > 0) end = 1; close_inode_for_write(rctx); diff --git a/send-stream.c b/send-stream.c index 5a028cd9..78f2571a 100644 --- a/send-stream.c +++ b/send-stream.c @@ -492,7 +492,7 @@ int btrfs_read_and_process_send_stream(int fd, if (ret < 0) goto out; if (ret) { - ret = 1; + ret = -ENODATA; goto out; }