From patchwork Thu Dec 20 16:23:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lars Ellenberg X-Patchwork-Id: 10739139 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3792114E5 for ; Thu, 20 Dec 2018 16:35:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2522E28E35 for ; Thu, 20 Dec 2018 16:35:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1863929129; Thu, 20 Dec 2018 16:35:01 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, 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 0A82328E35 for ; Thu, 20 Dec 2018 16:34:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733218AbeLTQet (ORCPT ); Thu, 20 Dec 2018 11:34:49 -0500 Received: from mail09.linbit.com ([212.69.161.110]:50101 "EHLO mail09.linbit.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730121AbeLTQek (ORCPT ); Thu, 20 Dec 2018 11:34:40 -0500 Received: from soda.linbit (212-186-191-219.static.upcbusiness.at [212.186.191.219]) by mail09.linbit.com (LINBIT Mail Daemon) with ESMTP id 14AA2103B4D2; Thu, 20 Dec 2018 17:23:46 +0100 (CET) From: Lars Ellenberg To: Jens Axboe , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Cc: drbd-dev@lists.linbit.com Subject: [PATCH 04/17] drbd: ignore "all zero" peer volume sizes in handshake Date: Thu, 20 Dec 2018 17:23:31 +0100 Message-Id: <20181220162344.8430-5-lars.ellenberg@linbit.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181220162344.8430-1-lars.ellenberg@linbit.com> References: <20181220162344.8430-1-lars.ellenberg@linbit.com> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP During handshake, if we are diskless ourselves, we used to accept any size presented by the peer. Which could be zero if that peer was just brought up and connected to us without having a disk attached first, in which case both peers would just "flip" their volume sizes. Now, even a diskless node will ignore "zero" sizes presented by a diskless peer. Also a currently Diskless Primary will refuse to shrink during handshake: it may be frozen, and waiting for a "suitable" local disk or peer to re-appear (on-no-data-accessible suspend-io). If the peer is smaller than what we used to be, it is not suitable. The logic for a diskless node during handshake is now supposed to be: believe the peer, if - I don't have a current size myself - we agree on the size anyways - I do have a current size, am Secondary, and he has the only disk - I do have a current size, am Primary, and he has the only disk, which is larger than my current size Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_receiver.c | 33 +++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 1b9822f264d2..fbf30fe45862 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -3981,6 +3981,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info struct o_qlim *o = (connection->agreed_features & DRBD_FF_WSAME) ? p->qlim : NULL; enum determine_dev_size dd = DS_UNCHANGED; sector_t p_size, p_usize, p_csize, my_usize; + sector_t new_size, cur_size; int ldsc = 0; /* local disk size changed */ enum dds_flags ddsf; @@ -3988,6 +3989,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info if (!peer_device) return config_unknown_volume(connection, pi); device = peer_device->device; + cur_size = drbd_get_capacity(device->this_bdev); p_size = be64_to_cpu(p->d_size); p_usize = be64_to_cpu(p->u_size); @@ -3998,7 +4000,6 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info device->p_size = p_size; if (get_ldev(device)) { - sector_t new_size, cur_size; rcu_read_lock(); my_usize = rcu_dereference(device->ldev->disk_conf)->disk_size; rcu_read_unlock(); @@ -4016,7 +4017,6 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info /* Never shrink a device with usable data during connect. But allow online shrinking if we are connected. */ new_size = drbd_new_dev_size(device, device->ldev, p_usize, 0); - cur_size = drbd_get_capacity(device->this_bdev); if (new_size < cur_size && device->state.disk >= D_OUTDATED && device->state.conn < C_CONNECTED) { @@ -4081,9 +4081,36 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info * * However, if he sends a zero current size, * take his (user-capped or) backing disk size anyways. + * + * Unless of course he does not have a disk himself. + * In which case we ignore this completely. */ + sector_t new_size = p_csize ?: p_usize ?: p_size; drbd_reconsider_queue_parameters(device, NULL, o); - drbd_set_my_capacity(device, p_csize ?: p_usize ?: p_size); + if (new_size == 0) { + /* Ignore, peer does not know nothing. */ + } else if (new_size == cur_size) { + /* nothing to do */ + } else if (cur_size != 0 && p_size == 0) { + drbd_warn(device, "Ignored diskless peer device size (peer:%llu != me:%llu sectors)!\n", + (unsigned long long)new_size, (unsigned long long)cur_size); + } else if (new_size < cur_size && device->state.role == R_PRIMARY) { + drbd_err(device, "The peer's device size is too small! (%llu < %llu sectors); demote me first!\n", + (unsigned long long)new_size, (unsigned long long)cur_size); + conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD); + return -EIO; + } else { + /* I believe the peer, if + * - I don't have a current size myself + * - we agree on the size anyways + * - I do have a current size, am Secondary, + * and he has the only disk + * - I do have a current size, am Primary, + * and he has the only disk, + * which is larger than my current size + */ + drbd_set_my_capacity(device, new_size); + } } if (get_ldev(device)) {