From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6A84C47087 for ; Thu, 7 Apr 2022 01:31:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242246AbiDGBc1 (ORCPT ); Wed, 6 Apr 2022 21:32:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239726AbiDGBT3 (ORCPT ); Wed, 6 Apr 2022 21:19:29 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8129E1AE21F; Wed, 6 Apr 2022 18:14:56 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C433BB8268D; Thu, 7 Apr 2022 01:14:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60D7CC385A6; Thu, 7 Apr 2022 01:14:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649294093; bh=V54235r8/iwJZHzZJh9Bx2Fl/u1D+DRFrFgDgmbY7eY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jmcqz7OcV9j9YXYSu8Jr9avVVfy5MoKJZGNzNu1QUZbpZp1AjN+6gCMyx5EyDXkXI U5Igp84plp/4sX8cu6N262cvAcVdlekqwEfy2/aniWf6rkJbZCWfG4/S6tIqpkqcvH q7qxIyFVvjWg+USjkx0jAf6u5IFMg1K+QpOnKDyFL9vJJPlleiLdqCptO+K9JXZ01A diXO4O1hIeNmgx8snivgNnvtJGyXhlCsz08fdWEerisNV6UdvjWjYVp5gZw8U8xoOd xN1SQqhZrBBk0MGCKhMpxDeUsSkI3Thdno0nVxKFnlJoz15yDTivDoVsoC1dtUbHnV J9vBDTnc7J78A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Anton Eidelman , Anton Eidelman , Sagi Grimberg , Christoph Hellwig , Sasha Levin , kbusch@kernel.org, axboe@fb.com, linux-nvme@lists.infradead.org Subject: [PATCH AUTOSEL 5.10 17/25] nvme-multipath: fix hang when disk goes live over reconnect Date: Wed, 6 Apr 2022 21:14:05 -0400 Message-Id: <20220407011413.114662-17-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220407011413.114662-1-sashal@kernel.org> References: <20220407011413.114662-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anton Eidelman [ Upstream commit a4a6f3c8f61c3cfbda4998ad94596059ad7e4332 ] nvme_mpath_init_identify() invoked from nvme_init_identify() fetches a fresh ANA log from the ctrl. This is essential to have an up to date path states for both existing namespaces and for those scan_work may discover once the ctrl is up. This happens in the following cases: 1) A new ctrl is being connected. 2) An existing ctrl is successfully reconnected. 3) An existing ctrl is being reset. While in (1) ctrl->namespaces is empty, (2 & 3) may have namespaces, and nvme_read_ana_log() may call nvme_update_ns_ana_state(). This result in a hang when the ANA state of an existing namespace changes and makes the disk live: nvme_mpath_set_live() issues IO to the namespace through the ctrl, which does NOT have IO queues yet. See sample hang below. Solution: - nvme_update_ns_ana_state() to call set_live only if ctrl is live - nvme_read_ana_log() call from nvme_mpath_init_identify() therefore only fetches and parses the ANA log; any erros in this process will fail the ctrl setup as appropriate; - a separate function nvme_mpath_update() is called in nvme_start_ctrl(); this parses the ANA log without fetching it. At this point the ctrl is live, therefore, disks can be set live normally. Sample failure: nvme nvme0: starting error recovery nvme nvme0: Reconnecting in 10 seconds... block nvme0n6: no usable path - requeuing I/O INFO: task kworker/u8:3:312 blocked for more than 122 seconds. Tainted: G E 5.14.5-1.el7.elrepo.x86_64 #1 Workqueue: nvme-wq nvme_tcp_reconnect_ctrl_work [nvme_tcp] Call Trace: __schedule+0x2a2/0x7e0 schedule+0x4e/0xb0 io_schedule+0x16/0x40 wait_on_page_bit_common+0x15c/0x3e0 do_read_cache_page+0x1e0/0x410 read_cache_page+0x12/0x20 read_part_sector+0x46/0x100 read_lba+0x121/0x240 efi_partition+0x1d2/0x6a0 bdev_disk_changed.part.0+0x1df/0x430 bdev_disk_changed+0x18/0x20 blkdev_get_whole+0x77/0xe0 blkdev_get_by_dev+0xd2/0x3a0 __device_add_disk+0x1ed/0x310 device_add_disk+0x13/0x20 nvme_mpath_set_live+0x138/0x1b0 [nvme_core] nvme_update_ns_ana_state+0x2b/0x30 [nvme_core] nvme_update_ana_state+0xca/0xe0 [nvme_core] nvme_parse_ana_log+0xac/0x170 [nvme_core] nvme_read_ana_log+0x7d/0xe0 [nvme_core] nvme_mpath_init_identify+0x105/0x150 [nvme_core] nvme_init_identify+0x2df/0x4d0 [nvme_core] nvme_init_ctrl_finish+0x8d/0x3b0 [nvme_core] nvme_tcp_setup_ctrl+0x337/0x390 [nvme_tcp] nvme_tcp_reconnect_ctrl_work+0x24/0x40 [nvme_tcp] process_one_work+0x1bd/0x360 worker_thread+0x50/0x3d0 Signed-off-by: Anton Eidelman Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- drivers/nvme/host/core.c | 1 + drivers/nvme/host/multipath.c | 25 +++++++++++++++++++++++-- drivers/nvme/host/nvme.h | 4 ++++ 3 files changed, 28 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 71c85c99e86c..3a3c28c639df 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -4409,6 +4409,7 @@ void nvme_start_ctrl(struct nvme_ctrl *ctrl) if (ctrl->queue_count > 1) { nvme_queue_scan(ctrl); nvme_start_queues(ctrl); + nvme_mpath_update(ctrl); } } EXPORT_SYMBOL_GPL(nvme_start_ctrl); diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 18a756444d5a..a9e15c8f907b 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -484,8 +484,17 @@ static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc, ns->ana_grpid = le32_to_cpu(desc->grpid); ns->ana_state = desc->state; clear_bit(NVME_NS_ANA_PENDING, &ns->flags); - - if (nvme_state_is_live(ns->ana_state)) + /* + * nvme_mpath_set_live() will trigger I/O to the multipath path device + * and in turn to this path device. However we cannot accept this I/O + * if the controller is not live. This may deadlock if called from + * nvme_mpath_init_identify() and the ctrl will never complete + * initialization, preventing I/O from completing. For this case we + * will reprocess the ANA log page in nvme_mpath_update() once the + * controller is ready. + */ + if (nvme_state_is_live(ns->ana_state) && + ns->ctrl->state == NVME_CTRL_LIVE) nvme_mpath_set_live(ns); } @@ -572,6 +581,18 @@ static void nvme_ana_work(struct work_struct *work) nvme_read_ana_log(ctrl); } +void nvme_mpath_update(struct nvme_ctrl *ctrl) +{ + u32 nr_change_groups = 0; + + if (!ctrl->ana_log_buf) + return; + + mutex_lock(&ctrl->ana_lock); + nvme_parse_ana_log(ctrl, &nr_change_groups, nvme_update_ana_state); + mutex_unlock(&ctrl->ana_lock); +} + static void nvme_anatt_timeout(struct timer_list *t) { struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer); diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 5dd1dd8021ba..58e3bb672ce3 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -707,6 +707,7 @@ void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id); void nvme_mpath_remove_disk(struct nvme_ns_head *head); int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id); void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl); +void nvme_mpath_update(struct nvme_ctrl *ctrl); void nvme_mpath_uninit(struct nvme_ctrl *ctrl); void nvme_mpath_stop(struct nvme_ctrl *ctrl); bool nvme_mpath_clear_current_path(struct nvme_ns *ns); @@ -793,6 +794,9 @@ static inline int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, "Please enable CONFIG_NVME_MULTIPATH for full support of multi-port devices.\n"); return 0; } +static inline void nvme_mpath_update(struct nvme_ctrl *ctrl) +{ +} static inline void nvme_mpath_uninit(struct nvme_ctrl *ctrl) { } -- 2.35.1