Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751677AbdGMLGN (ORCPT ); Thu, 13 Jul 2017 07:06:13 -0400 Received: from mx2.suse.de ([195.135.220.15]:43148 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751106AbdGMLGM (ORCPT ); Thu, 13 Jul 2017 07:06:12 -0400 From: Johannes Thumshirn To: Christoph Hellwig , Sagi Grimberg , Keith Busch Cc: mwilck@suse.de, Linux Kernel Mailinglist , Linux NVMe Mailinglist , Johannes Thumshirn Subject: [PATCH] nvmet: preserve controller serial number between reboots Date: Thu, 13 Jul 2017 12:48:06 +0200 Message-Id: <20170713104806.12353-1-jthumshirn@suse.de> X-Mailer: git-send-email 2.12.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2675 Lines: 83 The NVMe target has no way to preserve controller serial IDs across reboots which breaks udev scripts doing SYMLINK+="dev/disk/by-id/nvme-$env{ID_SERIAL}-part%n. Export the randomly generated serial number via configfs and allow setting of a serial via configfs to mitigate this breakage. Signed-off-by: Johannes Thumshirn --- drivers/nvme/target/configfs.c | 22 ++++++++++++++++++++++ drivers/nvme/target/core.c | 8 ++++++-- drivers/nvme/target/nvmet.h | 1 + 3 files changed, 29 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c index a358ecd93e11..9f19f0bde8f2 100644 --- a/drivers/nvme/target/configfs.c +++ b/drivers/nvme/target/configfs.c @@ -686,9 +686,31 @@ static ssize_t nvmet_subsys_version_store(struct config_item *item, } CONFIGFS_ATTR(nvmet_subsys_, version); +static ssize_t nvmet_subsys_attr_serial_show(struct config_item *item, + char *page) +{ + struct nvmet_subsys *subsys = to_subsys(item); + + return snprintf(page, PAGE_SIZE, "%llx\n", subsys->serial); +} + +static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item, + const char *page, size_t count) +{ + struct nvmet_subsys *subsys = to_subsys(item); + + down_write(&nvmet_config_sem); + sscanf(page, "%llx\n", &subsys->serial); + up_write(&nvmet_config_sem); + + return count; +} +CONFIGFS_ATTR(nvmet_subsys_, attr_serial); + static struct configfs_attribute *nvmet_subsys_attrs[] = { &nvmet_subsys_attr_attr_allow_any_host, &nvmet_subsys_attr_version, + &nvmet_subsys_attr_attr_serial, NULL, }; diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c index b5b4ac103748..6967580ffecf 100644 --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -767,8 +767,12 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn, memcpy(ctrl->subsysnqn, subsysnqn, NVMF_NQN_SIZE); memcpy(ctrl->hostnqn, hostnqn, NVMF_NQN_SIZE); - /* generate a random serial number as our controllers are ephemeral: */ - get_random_bytes(&ctrl->serial, sizeof(ctrl->serial)); + down_read(&nvmet_config_sem); + if (!subsys->serial) + get_random_bytes(&subsys->serial, sizeof(subsys->serial)); + up_read(&nvmet_config_sem); + + ctrl->serial = subsys->serial; kref_init(&ctrl->ref); ctrl->subsys = subsys; diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h index 747bbdb4f9c6..68c97d73e387 100644 --- a/drivers/nvme/target/nvmet.h +++ b/drivers/nvme/target/nvmet.h @@ -152,6 +152,7 @@ struct nvmet_subsys { u16 max_qid; u64 ver; + u64 serial; char *subsysnqn; struct config_group group; -- 2.12.3